WorldWideScience

Sample records for crystallization condition screening

  1. Structure of curved crystals in the thermodynamic limit and the perfect screening condition

    Science.gov (United States)

    Travesset, Alex

    2016-12-01

    The dislocation and disclination density defining the structure of a crystal constrained on a general curved background is computed analytically in the thermodynamic limit, when the number of particles is arbitrarily large. It is shown that the minimum of the elastic energy, where strains are optimally close to zero, can be formulated in terms of a connection (a rule on how to parallel transport vectors), which allows to provide an explicit solution in the thermodynamic limit that consists of disclinations surrounded by scars (grain boundaries with variable spacing). The approach allows to compute the interaction potential. For a sphere, a full characterization of the scars is provided, and it is shown that the potential of interaction among disclinations "dressed" by scars is inversely proportional to the sinus of the geodesic distance and that the ground state consists of 12 dressed disclinations that display icosahedral symmetry. The case of a torus is also considered. More generally, the thermodynamic solution implements a "perfect screening" condition, where defects completely screen the Gaussian curvature. Implications for the problem of melting are discussed.

  2. High-throughput crystallization screening.

    Science.gov (United States)

    Skarina, Tatiana; Xu, Xiaohui; Evdokimova, Elena; Savchenko, Alexei

    2014-01-01

    Protein structure determination by X-ray crystallography is dependent on obtaining a single protein crystal suitable for diffraction data collection. Due to this requirement, protein crystallization represents a key step in protein structure determination. The conditions for protein crystallization have to be determined empirically for each protein, making this step also a bottleneck in the structure determination process. Typical protein crystallization practice involves parallel setup and monitoring of a considerable number of individual protein crystallization experiments (also called crystallization trials). In these trials the aliquots of purified protein are mixed with a range of solutions composed of a precipitating agent, buffer, and sometimes an additive that have been previously successful in prompting protein crystallization. The individual chemical conditions in which a particular protein shows signs of crystallization are used as a starting point for further crystallization experiments. The goal is optimizing the formation of individual protein crystals of sufficient size and quality to make them suitable for diffraction data collection. Thus the composition of the primary crystallization screen is critical for successful crystallization.Systematic analysis of crystallization experiments carried out on several hundred proteins as part of large-scale structural genomics efforts allowed the optimization of the protein crystallization protocol and identification of a minimal set of 96 crystallization solutions (the "TRAP" screen) that, in our experience, led to crystallization of the maximum number of proteins.

  3. Defined PEG smears as an alternative approach to enhance the search for crystallization conditions and crystal-quality improvement in reduced screens

    Energy Technology Data Exchange (ETDEWEB)

    Chaikuad, Apirat, E-mail: apirat.chaikuad@sgc.ox.ac.uk [University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ (United Kingdom); Knapp, Stefan [University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ (United Kingdom); Johann Wolfgang Goethe-University, Building N240 Room 3.03, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main (Germany); Delft, Frank von, E-mail: apirat.chaikuad@sgc.ox.ac.uk [University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ (United Kingdom)

    2015-07-28

    An alternative strategy for PEG sampling is suggested through the use of four newly defined PEG smears to enhance chemical space in reduced screens with a benefit towards protein crystallization. The quest for an optimal limited set of effective crystallization conditions remains a challenge in macromolecular crystallography, an issue that is complicated by the large number of chemicals which have been deemed to be suitable for promoting crystal growth. The lack of rational approaches towards the selection of successful chemical space and representative combinations has led to significant overlapping conditions, which are currently present in a multitude of commercially available crystallization screens. Here, an alternative approach to the sampling of widely used PEG precipitants is suggested through the use of PEG smears, which are mixtures of different PEGs with a requirement of either neutral or cooperatively positive effects of each component on crystal growth. Four newly defined smears were classified by molecular-weight groups and enabled the preservation of specific properties related to different polymer sizes. These smears not only allowed a wide coverage of properties of these polymers, but also reduced PEG variables, enabling greater sampling of other parameters such as buffers and additives. The efficiency of the smear-based screens was evaluated on more than 220 diverse recombinant human proteins, which overall revealed a good initial crystallization success rate of nearly 50%. In addition, in several cases successful crystallizations were only obtained using PEG smears, while various commercial screens failed to yield crystals. The defined smears therefore offer an alternative approach towards PEG sampling, which will benefit the design of crystallization screens sampling a wide chemical space of this key precipitant.

  4. The MORPHEUS II protein crystallization screen.

    Science.gov (United States)

    Gorrec, Fabrice

    2015-07-01

    High-quality macromolecular crystals are a prerequisite for the process of protein structure determination by X-ray diffraction. Unfortunately, the relative yield of diffraction-quality crystals from crystallization experiments is often very low. In this context, innovative crystallization screen formulations are continuously being developed. In the past, MORPHEUS, a screen in which each condition integrates a mix of additives selected from the Protein Data Bank, a cryoprotectant and a buffer system, was developed. Here, MORPHEUS II, a follow-up to the original 96-condition initial screen, is described. Reagents were selected to yield crystals when none might be observed in traditional initial screens. Besides, the screen includes heavy atoms for experimental phasing and small polyols to ensure the cryoprotection of crystals. The suitability of the resulting novel conditions is shown by the crystallization of a broad variety of protein samples and their efficiency is compared with commercially available conditions.

  5. Mimer: an automated spreadsheet-based crystallization screening system.

    Science.gov (United States)

    Brodersen, Ditlev Egeskov; Andersen, Gregers Rom; Andersen, Christian Brix Folsted

    2013-07-01

    In this paper, a simple low-cost alternative to large commercial systems for preparing macromolecular crystallization conditions is described. Using an intuitive spreadsheet-based approach, the system allows the rapid calculation of relevant pipetting volumes given known stock-solution concentrations and incorporates the automatic design of custom crystallization screens via the incomplete-factorial and grid-screen approaches. Automated dispensing of the resulting crystallization screens is achieved using a generic and relatively inexpensive liquid handler.

  6. Detergent-Specific Membrane Protein Crystallization Screens

    Science.gov (United States)

    Wiener, Michael

    2007-01-01

    A suite of reagents has been developed for three-dimensional crystallization of integral membranes present in solution as protein-detergent complexes (PDCs). The compositions of these reagents have been determined in part by proximity to the phase boundaries (lower consolute boundaries) of the detergents present in the PDCs. The acquisition of some of the requisite phase-boundary data and the preliminary design of several of the detergent- specific screens was supported by a NASA contract. At the time of expiration of the contract, a partial set of preliminary screens had been developed. This work has since been extended under non-NASA sponsorship, leading to near completion of a set of 20 to 30 different and unique detergent- specific 96-condition screens.

  7. An automated pipeline to screen membrane protein 2D crystallization.

    Science.gov (United States)

    Kim, Changki; Vink, Martin; Hu, Minghui; Love, James; Stokes, David L; Ubarretxena-Belandia, Iban

    2010-06-01

    Electron crystallography relies on electron cryomicroscopy of two-dimensional (2D) crystals and is particularly well suited for studying the structure of membrane proteins in their native lipid bilayer environment. To obtain 2D crystals from purified membrane proteins, the detergent in a protein-lipid-detergent ternary mixture must be removed, generally by dialysis, under conditions favoring reconstitution into proteoliposomes and formation of well-ordered lattices. To identify these conditions a wide range of parameters such as pH, lipid composition, lipid-to-protein ratio, ionic strength and ligands must be screened in a procedure involving four steps: crystallization, specimen preparation for electron microscopy, image acquisition, and evaluation. Traditionally, these steps have been carried out manually and, as a result, the scope of 2D crystallization trials has been limited. We have therefore developed an automated pipeline to screen the formation of 2D crystals. We employed a 96-well dialysis block for reconstitution of the target protein over a wide range of conditions designed to promote crystallization. A 96-position magnetic platform and a liquid handling robot were used to prepare negatively stained specimens in parallel. Robotic grid insertion into the electron microscope and computerized image acquisition ensures rapid evaluation of the crystallization screen. To date, 38 2D crystallization screens have been conducted for 15 different membrane proteins, totaling over 3000 individual crystallization experiments. Three of these proteins have yielded diffracting 2D crystals. Our automated pipeline outperforms traditional 2D crystallization methods in terms of throughput and reproducibility.

  8. Nanoliter-scale protein crystallization and screening with a microfluidic droplet robot.

    Science.gov (United States)

    Zhu, Ying; Zhu, Li-Na; Guo, Rui; Cui, Heng-Jun; Ye, Sheng; Fang, Qun

    2014-05-23

    Large-scale screening of hundreds or even thousands of crystallization conditions while with low sample consumption is in urgent need, in current structural biology research. Here we describe a fully-automated droplet robot for nanoliter-scale crystallization screening that combines the advantages of both automated robotics technique for protein crystallization screening and the droplet-based microfluidic technique. A semi-contact dispensing method was developed to achieve flexible, programmable and reliable liquid-handling operations for nanoliter-scale protein crystallization experiments. We applied the droplet robot in large-scale screening of crystallization conditions of five soluble proteins and one membrane protein with 35-96 different crystallization conditions, study of volume effects on protein crystallization, and determination of phase diagrams of two proteins. The volume for each droplet reactor is only ca. 4-8 nL. The protein consumption significantly reduces 50-500 fold compared with current crystallization stations.

  9. Nanoliter-Scale Protein Crystallization and Screening with a Microfluidic Droplet Robot

    OpenAIRE

    Ying Zhu; Li-Na Zhu; Rui Guo; Heng-Jun Cui; Sheng Ye; Qun Fang

    2014-01-01

    Large-scale screening of hundreds or even thousands of crystallization conditions while with low sample consumption is in urgent need, in current structural biology research. Here we describe a fully-automated droplet robot for nanoliter-scale crystallization screening that combines the advantages of both automated robotics technique for protein crystallization screening and the droplet-based microfluidic technique. A semi-contact dispensing method was developed to achieve flexible, programma...

  10. Crystallization screening: the influence of history on current practice.

    Science.gov (United States)

    Luft, Joseph R; Newman, Janet; Snell, Edward H

    2014-07-01

    While crystallization historically predates crystallography, it is a critical step for the crystallographic process. The rich history of crystallization and how that history influences current practices is described. The tremendous impact of crystallization screens on the field is discussed.

  11. Steady-State Screening-Photovoltaic Spatial Solitons in the Biased Photorefractive-Photovoltaic Crystals

    Institute of Scientific and Technical Information of China (English)

    LU Ke-Qing; ZHANG Yan-Peng; TANG Tian-Tong; LU Zhi-Xian; LIU Lin

    2001-01-01

    The theory of the screening-photovoltaic solitons is improved in biased photorefractive-photovoltaic crystals. When the photovoltaic effect is negligible, the screening-photovoltaic solitons are the screening ones, and their space-charge field is the space-charge field of the screening solitons. If the external field is absent, the screening photovoltaic solitons are the photovoltaic ones on the open- and closed-circuit conditions, and their space-charge field is of the photovoltaic solitons. We also show theoretically that the screening and the photovoltaic solitons on the open- and closed-circuit conditions may be studies together as the screening-photovoltaic solitons.

  12. INCOHERENTLY COUPLED SCREENING-PHOTOVOLTAIC SOLITON FAMILIES IN BIASED PHOTOVOLTAIC PHOTOREFRACTIVE CRYSTALS

    Institute of Scientific and Technical Information of China (English)

    HOU CHUN-FENG; LI BIN; SUN XIU-DONG; JIANG YONG-YUAN; XU KE-BIN

    2001-01-01

    It is shown that the existence of incoherently coupled screening-photovoltaic soliton families is possible in biased photovoltaic photorefractive crystals under steady-state conditions. These screening-photovoltaic soliton families can be established provided the multiple incident beams have the same polarization and wavelength, and are mutually incoherent. Such soliton families reduce to screening-photovoltaic soliton pairs when they contain only two components. Relevant examples are presented where the photovoltaic photorefractive crystal is of the lithium niobate type.

  13. Automated High Throughput Protein Crystallization Screening at Nanoliter Scale and Protein Structural Study on Lactate Dehydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fenglei [Iowa State Univ., Ames, IA (United States)

    2006-08-09

    The purposes of our research were: (1) To develop an economical, easy to use, automated, high throughput system for large scale protein crystallization screening. (2) To develop a new protein crystallization method with high screening efficiency, low protein consumption and complete compatibility with high throughput screening system. (3) To determine the structure of lactate dehydrogenase complexed with NADH by x-ray protein crystallography to study its inherent structural properties. Firstly, we demonstrated large scale protein crystallization screening can be performed in a high throughput manner with low cost, easy operation. The overall system integrates liquid dispensing, crystallization and detection and serves as a whole solution to protein crystallization screening. The system can dispense protein and multiple different precipitants in nanoliter scale and in parallel. A new detection scheme, native fluorescence, has been developed in this system to form a two-detector system with a visible light detector for detecting protein crystallization screening results. This detection scheme has capability of eliminating common false positives by distinguishing protein crystals from inorganic crystals in a high throughput and non-destructive manner. The entire system from liquid dispensing, crystallization to crystal detection is essentially parallel, high throughput and compatible with automation. The system was successfully demonstrated by lysozyme crystallization screening. Secondly, we developed a new crystallization method with high screening efficiency, low protein consumption and compatibility with automation and high throughput. In this crystallization method, a gas permeable membrane is employed to achieve the gentle evaporation required by protein crystallization. Protein consumption is significantly reduced to nanoliter scale for each condition and thus permits exploring more conditions in a phase diagram for given amount of protein. In addition

  14. Morphology Changing at Incipient Crystallization Condition

    Science.gov (United States)

    Toshima, Takeshi; Hamai, Ryo; Fujita, Saya; Takemura, Yuka; Takamatsu, Saori; Tafu, Masamoto

    2015-04-01

    Brushite (Dicalcium phosphate dihydrate, (DCPD), CaHPO4·2H2O) is one of key components in calcium phosphate system due to wide attractive material not only as bioceramics but also environmental materials. Morphology of DCPD crystals is important factor when one uses its functionality with chemical reaction; because its surface crystal face, shape and size rule the chemical reactivity, responsiveness. Moreover, physical properties are also changed the morphology; such as cohesion, dispersiveness, permeability and so on. If one uses DCPD crystals as environmental renovation materials to catch the fluoride ions, their shape require 020 crystal surfaces; which usually restricts their shape as plate-like structure. After the chemical reaction, the shape of sludge is not good for handling due to their agglutinate property. Therefore searching an effective parameter and developing the method to control the morphology of DCPD crystals is required. In past, we reported that initial concentration and pH value of starting solution, prepared by dissolving calcium nitrate, Ca(NO3)2 and ammonium dihydrogen phosphate, NH4H2PO4, changes the morphology of DCPD crystals and phase diagram of morphology of DCPD crystal depend on those parameter. The DCPD crystallization shows unique behaviour; products obtained higher initial concentration form single crystal-like structure and under lower condition, they form agglomerate crystal-like structure. These results contradict usual crystallization. Here we report that the effect of mixing process of two solutions. The morphology of DCPD crystals is changed from plate structure to petal structure by the arrangement. Our result suggests that morphology of DCPD crystals strongly depends at incipient crystallization condition and growth form is controllable by setting initial crystallization condition.

  15. Sparse and incomplete factorial matrices to screen membrane protein 2D crystallization.

    Science.gov (United States)

    Lasala, R; Coudray, N; Abdine, A; Zhang, Z; Lopez-Redondo, M; Kirshenbaum, R; Alexopoulos, J; Zolnai, Z; Stokes, D L; Ubarretxena-Belandia, I

    2015-02-01

    Electron crystallography is well suited for studying the structure of membrane proteins in their native lipid bilayer environment. This technique relies on electron cryomicroscopy of two-dimensional (2D) crystals, grown generally by reconstitution of purified membrane proteins into proteoliposomes under conditions favoring the formation of well-ordered lattices. Growing these crystals presents one of the major hurdles in the application of this technique. To identify conditions favoring crystallization a wide range of factors that can lead to a vast matrix of possible reagent combinations must be screened. However, in 2D crystallization these factors have traditionally been surveyed in a relatively limited fashion. To address this problem we carried out a detailed analysis of published 2D crystallization conditions for 12 β-barrel and 138 α-helical membrane proteins. From this analysis we identified the most successful conditions and applied them in the design of new sparse and incomplete factorial matrices to screen membrane protein 2D crystallization. Using these matrices we have run 19 crystallization screens for 16 different membrane proteins totaling over 1300 individual crystallization conditions. Six membrane proteins have yielded diffracting 2D crystals suitable for structure determination, indicating that these new matrices show promise to accelerate the success rate of membrane protein 2D crystallization.

  16. High-throughput method for optimum solubility screening for homogeneity and crystallization of proteins

    Science.gov (United States)

    Kim, Sung-Hou [Moraga, CA; Kim, Rosalind [Moraga, CA; Jancarik, Jamila [Walnut Creek, CA

    2012-01-31

    An optimum solubility screen in which a panel of buffers and many additives are provided in order to obtain the most homogeneous and monodisperse protein condition for protein crystallization. The present methods are useful for proteins that aggregate and cannot be concentrated prior to setting up crystallization screens. A high-throughput method using the hanging-drop method and vapor diffusion equilibrium and a panel of twenty-four buffers is further provided. Using the present methods, 14 poorly behaving proteins have been screened, resulting in 11 of the proteins having highly improved dynamic light scattering results allowing concentration of the proteins, and 9 were crystallized.

  17. Crystallization screening: the influence of history on current practice

    Science.gov (United States)

    Luft, Joseph R.; Newman, Janet; Snell, Edward H.

    2014-01-01

    While crystallization historically predates crystallography, it is a critical step for the crystallographic process. The rich history of crystallization and how that history influences current practices is described. The tremendous impact of crystallization screens on the field is discussed. PMID:25005076

  18. Nanoliter-scale protein crystallization and screening with a microfluidic droplet robot

    National Research Council Canada - National Science Library

    Zhu, Ying; Zhu, Li-Na; Guo, Rui; Cui, Heng-Jun; Ye, Sheng; Fang, Qun

    2014-01-01

    .... Here we describe a fully-automated droplet robot for nanoliter-scale crystallization screening that combines the advantages of both automated robotics technique for protein crystallization screening...

  19. Crystallization of nepenthesin I using a low-pH crystallization screen.

    Science.gov (United States)

    Fejfarová, Karla; Kádek, Alan; Mrázek, Hynek; Hausner, Jiří; Tretyachenko, Vyacheslav; Koval', Tomáš; Man, Petr; Hašek, Jindřich; Dohnálek, Jan

    2016-01-01

    Nepenthesins are aspartic proteases secreted by carnivorous pitcher plants of the genus Nepenthes. They significantly differ in sequence from other plant aspartic proteases. This difference, which provides more cysteine residues in the structure of nepenthesins, may contribute to their unique stability profile. Recombinantly produced nepenthesin 1 (rNep1) from N. gracilis in complex with pepstatin A was crystallized under two different crystallization conditions using a newly formulated low-pH crystallization screen. The diffraction data were processed to 2.9 and 2.8 Å resolution, respectively. The crystals belonged to space group P212121, with unit-cell parameters a = 86.63, b = 95.90, c = 105.40 Å, α = β = γ = 90° and a = 86.28, b = 97.22, c = 103.78 Å, α = β = γ = 90°, respectively. Matthews coefficient and solvent-content calculations suggest the presence of two molecules of rNep1 in the asymmetric unit. Here, the details of the crystallization experiment and analysis of the X-ray data are reported.

  20. Acoustic transfer of protein crystals from agarose pedestals to micromeshes for high-throughput screening

    Energy Technology Data Exchange (ETDEWEB)

    Cuttitta, Christina M. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); The City University of New York, 2800 Victory Boulevard, Staten Island, NY 10314 (United States); Ericson, Daniel L. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); University at Buffalo, SUNY, 12 Capen Hall, Buffalo, NY 14260 (United States); Scalia, Alexander [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Binghamton University, 4400 Vestal Parkway East, Binghamton, NY 11973-5000 (United States); Roessler, Christian G. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Teplitsky, Ella [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Stony Brook University, Stony Brook, NY 11794-5215 (United States); Joshi, Karan [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); PEC University of Technology, Chandigarh (India); Campos, Olven [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33414 (United States); Agarwal, Rakhi; Allaire, Marc [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Orville, Allen M. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Sweet, Robert M.; Soares, Alexei S., E-mail: soares@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

    2015-01-01

    An acoustic high-throughput screening method is described for harvesting protein crystals and combining the protein crystals with chemicals such as a fragment library. Acoustic droplet ejection (ADE) is an emerging technology with broad applications in serial crystallography such as growing, improving and manipulating protein crystals. One application of this technology is to gently transfer crystals onto MiTeGen micromeshes with minimal solvent. Once mounted on a micromesh, each crystal can be combined with different chemicals such as crystal-improving additives or a fragment library. Acoustic crystal mounting is fast (2.33 transfers s{sup −1}) and all transfers occur in a sealed environment that is in vapor equilibrium with the mother liquor. Here, a system is presented to retain crystals near the ejection point and away from the inaccessible dead volume at the bottom of the well by placing the crystals on a concave agarose pedestal (CAP) with the same chemical composition as the crystal mother liquor. The bowl-shaped CAP is impenetrable to crystals. Consequently, gravity will gently move the crystals into the optimal location for acoustic ejection. It is demonstrated that an agarose pedestal of this type is compatible with most commercially available crystallization conditions and that protein crystals are readily transferred from the agarose pedestal onto micromeshes with no loss in diffraction quality. It is also shown that crystals can be grown directly on CAPs, which avoids the need to transfer the crystals from the hanging drop to a CAP. This technology has been used to combine thermolysin and lysozyme crystals with an assortment of anomalously scattering heavy atoms. The results point towards a fast nanolitre method for crystal mounting and high-throughput screening.

  1. Improved success of sparse matrix protein crystallization screening with heterogeneous nucleating agents.

    Directory of Open Access Journals (Sweden)

    Anil S Thakur

    Full Text Available BACKGROUND: Crystallization is a major bottleneck in the process of macromolecular structure determination by X-ray crystallography. Successful crystallization requires the formation of nuclei and their subsequent growth to crystals of suitable size. Crystal growth generally occurs spontaneously in a supersaturated solution as a result of homogenous nucleation. However, in a typical sparse matrix screening experiment, precipitant and protein concentration are not sampled extensively, and supersaturation conditions suitable for nucleation are often missed. METHODOLOGY/PRINCIPAL FINDINGS: We tested the effect of nine potential heterogenous nucleating agents on crystallization of ten test proteins in a sparse matrix screen. Several nucleating agents induced crystal formation under conditions where no crystallization occurred in the absence of the nucleating agent. Four nucleating agents: dried seaweed; horse hair; cellulose and hydroxyapatite, had a considerable overall positive effect on crystallization success. This effect was further enhanced when these nucleating agents were used in combination with each other. CONCLUSIONS/SIGNIFICANCE: Our results suggest that the addition of heterogeneous nucleating agents increases the chances of crystal formation when using sparse matrix screens.

  2. Screening length in dusty plasma crystals

    Science.gov (United States)

    Nikolaev, V. S.; Timofeev, A. V.

    2016-11-01

    Particles interaction and value of the screening length in dusty plasma systems are of great interest in dusty plasma area. Three inter-particle potentials (Debye potential, Gurevich potential and interaction potential in the weakly collisional regime) are used to solve equilibrium equations for two dusty particles suspended in a parabolic trap. The inter-particle distance dependence on screening length, trap parameter and particle charge is obtained. The functional form of inter-particle distance dependence on ion temperature is investigated and compared with experimental data at 200-300 K in order to test used potentials applicability to dusty plasma systems at room temperatures. The preference is given to the Yukawa-type potential including effective values of particle charge and screening length. The estimated effective value of the screening length is 5-15 times larger than the Debye length.

  3. Screening for templates that promote crystallization

    NARCIS (Netherlands)

    Urbanus, J.; Roelands, C.P.M.; Horst, J.H. ter; Verdoes, D.; Jansens, P.J.

    2008-01-01

    In Situ Product Recovery (ISPR) applied in fermentation processes leads to improved yield and productivity of these processes. In principle, ISPR can be achieved using Template Induced Crystallization (TIC), which is one possible ISPR technique. With TIC, templates are added to the solution as a spe

  4. Acoustic transfer of protein crystals from agarose pedestals to micromeshes for high-throughput screening.

    Science.gov (United States)

    Cuttitta, Christina M; Ericson, Daniel L; Scalia, Alexander; Roessler, Christian G; Teplitsky, Ella; Joshi, Karan; Campos, Olven; Agarwal, Rakhi; Allaire, Marc; Orville, Allen M; Sweet, Robert M; Soares, Alexei S

    2015-01-01

    Acoustic droplet ejection (ADE) is an emerging technology with broad applications in serial crystallography such as growing, improving and manipulating protein crystals. One application of this technology is to gently transfer crystals onto MiTeGen micromeshes with minimal solvent. Once mounted on a micromesh, each crystal can be combined with different chemicals such as crystal-improving additives or a fragment library. Acoustic crystal mounting is fast (2.33 transfers s(-1)) and all transfers occur in a sealed environment that is in vapor equilibrium with the mother liquor. Here, a system is presented to retain crystals near the ejection point and away from the inaccessible dead volume at the bottom of the well by placing the crystals on a concave agarose pedestal (CAP) with the same chemical composition as the crystal mother liquor. The bowl-shaped CAP is impenetrable to crystals. Consequently, gravity will gently move the crystals into the optimal location for acoustic ejection. It is demonstrated that an agarose pedestal of this type is compatible with most commercially available crystallization conditions and that protein crystals are readily transferred from the agarose pedestal onto micromeshes with no loss in diffraction quality. It is also shown that crystals can be grown directly on CAPs, which avoids the need to transfer the crystals from the hanging drop to a CAP. This technology has been used to combine thermolysin and lysozyme crystals with an assortment of anomalously scattering heavy atoms. The results point towards a fast nanolitre method for crystal mounting and high-throughput screening.

  5. Carbamazepine-Fumaric Acid Co-Crystal Screening Using Solution Based Method

    Directory of Open Access Journals (Sweden)

    Abd Rahim Syarifah

    2016-01-01

    Full Text Available Co-crystals is a multi-component system which connected by non-covalent interactions, present physically as a solid form under ambient conditions. Nowadays, co-crystal has becoming as an alternative approach to improve the bioavailability of poor water soluble drugs especially for a weakly ionisable groups or neutral compounds. In this study the co-crystal screening was carried out for carbamazepine (CBZ and fumaric acid (FUM co-crystal former (CCF using non-stoichiometric method (addition of CBZ to CCF saturated solution and stoichiometric method (evaporation of 1:1 molar ratio of CBZ to CCF in acetonitrile, ethyl acetate, propanol, ethanol and formic acid solvent systems. The crystals produced from the screening were characterized using Powder X-ray Diffraction (PXRD, Differential Scanning Calorimetry (DSC and Fourier Transform Infrared (FT-IR. The PXRD analysis had confirmed that the co-crystal was successfully formed in both methods for all of the solvent system studied with an exception to formic acid in the stoichiometric method where no crystal was found precipitate. The findings from this study revealed that Form A and Form B of CBZ-FUM co-crystal had been successfully formed from different solvent systems.

  6. TCR/pMHC Optimized Protein crystallization Screen

    Science.gov (United States)

    Bulek, Anna M.; Madura, Florian; Fuller, Anna; Holland, Christopher J.; Schauenburg, Andrea J.A.; Sewell, Andrew K.; Rizkallah, Pierre J.; Cole, David K.

    2012-01-01

    The interaction between the clonotypic αβ T cell receptor (TCR), expressed on the T cell surface, and peptide-major histocompatibility complex (pMHC) molecules, expressed on the target cell surface, governs T cell mediated autoimmunity and immunity against pathogens and cancer. Structural investigations of this interaction have been limited because of the challenges inherent in the production of good quality TCR/pMHC protein crystals. Here, we report the development of an ‘intelligently designed’ crystallization screen that reproducibly generates high quality TCR/pMHC complex crystals suitable for X-ray crystallographic studies, thereby reducing protein consumption. Over the last 2 years, we have implemented this screen to produce 32 T cell related protein structures at high resolution, substantially contributing to the current immune protein database. Protein crystallography, used to study this interaction, has already extended our understanding of the molecular rules that govern T cell immunity. Subsequently, these data may help to guide the intelligent design of T cell based therapies that target human diseases, underlining the importance of developing optimized approaches for crystallizing novel TCR/pMHC complexes. PMID:22705983

  7. A high-throughput strategy to screen 2D crystallization trials of membrane proteins.

    Science.gov (United States)

    Vink, Martin; Derr, Kd; Love, James; Stokes, David L; Ubarretxena-Belandia, Iban

    2007-12-01

    Electron microscopy of two-dimensional (2D) crystals has demonstrated potential for structure determination of membrane proteins. Technical limitations in large-scale crystallization screens have, however, prevented a major breakthrough in the routine application of this technology. Dialysis is generally used for detergent removal and reconstitution of the protein into a lipid bilayer, and devices for testing numerous conditions in parallel are not readily available. Furthermore, the small size of resulting 2D crystals requires electron microscopy to evaluate the results and automation of the necessary steps is essential to achieve a reasonable throughput. We have designed a crystallization block, using standard microplate dimensions, by which 96 unique samples can be dialyzed simultaneously against 96 different buffers and have demonstrated that the rate of detergent dialysis is comparable to those obtained with conventional dialysis devices. A liquid-handling robot was employed to set up 2D crystallization trials with the membrane proteins CopA from Archaeoglobus fulgidus and light-harvesting complex II (LH2) from Rhodobacter sphaeroides. For CopA, 1 week of dialysis yielded tubular crystals and, for LH2, large and well-ordered vesicular 2D crystals were obtained after 24 h, illustrating the feasibility of this approach. Combined with a high-throughput procedure for preparation of EM-grids and automation of the subsequent negative staining step, the crystallization block offers a novel pipeline that promises to speed up large-scale screening of 2D crystallization and to increase the likelihood of producing well-ordered crystals for analysis by electron crystallography.

  8. Combined crystal structure prediction and high-pressure crystallization in rational pharmaceutical polymorph screening

    DEFF Research Database (Denmark)

    Neumann, M A; van de Streek, J; Fabbiani, F P A

    2015-01-01

    Organic molecules, such as pharmaceuticals, agro-chemicals and pigments, frequently form several crystal polymorphs with different physicochemical properties. Finding polymorphs has long been a purely experimental game of trial-and-error. Here we utilize in silico polymorph screening in combination...

  9. Self-interaction chromatography as a tool for optimizing conditions for membrane protein crystallization.

    Science.gov (United States)

    Gabrielsen, Mads; Nagy, Lisa A; DeLucas, Lawrence J; Cogdell, Richard J

    2010-01-01

    The second virial coefficient, or B value, is a measurement of how well a protein interacts with itself in solution. These interactions can lead to protein crystallization or precipitation, depending on their strength, with a narrow range of B values (the 'crystallization slot') being known to promote crystallization. A convenient method of determining the B value is by self-interaction chromatography. This paper describes how the light-harvesting complex 1-reaction centre core complex from Allochromatium vinosum yielded single straight-edged crystals after iterative cycles of self-interaction chromatography and crystallization. This process allowed the rapid screening of small molecules and detergents as crystallization additives. Here, a description is given of how self-interaction chromatography has been utilized to improve the crystallization conditions of a membrane protein.

  10. [Screening for asbestos-related conditions

    DEFF Research Database (Denmark)

    Brauer, C.; Baandrup, U.; Jacobsen, P.

    2009-01-01

    Screening programs for early detection of asbestos-related cancer have been considered. Conventional X-ray, computed tomography of the thorax, and the biomarkers osteopontin and mesothelin have been critically reviewed in the literature, together with survival data from screening programs...... in asbestos-exposed populations. Data do not currently support implementation of screening programs for asbestos-exposed persons in Denmark. Since mesothelioma is most often an occupational disease, these patients should be admitted to an occupational clinic for aetiological evaluation Udgivelsesdato: 2009/2/2...

  11. Four-Dimensional Screening Anti-Counterfeiting Pattern by Inkjet Printed Photonic Crystals.

    Science.gov (United States)

    Hou, Jue; Zhang, Huacheng; Su, Bin; Li, Mingzhu; Yang, Qiang; Jiang, Lei; Song, Yanlin

    2016-10-06

    A four-dimensional screening anti-counterfeiting QR code composed of differently shaped photonic crystal (PC) dots has been fabricated that could display four images depending on different lighting conditions. By controlling the rheology of poly(dimethylsiloxane) (PDMS), three kinds of PC dots could be sequentially integrated into one pattern using the layer-by-layer printing strategy. The information can be encoded and stored in shapes and read out by the difference in optical properties.

  12. Protein crystallization with microseed matrix screening: application to human germline antibody Fabs

    Energy Technology Data Exchange (ETDEWEB)

    Obmolova, Galina, E-mail: gobmolov@its.jnj.com; Malia, Thomas J.; Teplyakov, Alexey; Sweet, Raymond W.; Gilliland, Gary L., E-mail: gobmolov@its.jnj.com [Janssen Research and Development LLC, 1400 McKean Road, Spring House, PA 19477 (United States)

    2014-07-23

    The power of microseed matrix screening is demonstrated in the crystallization of a panel of antibody Fab fragments. The crystallization of 16 human antibody Fab fragments constructed from all pairs of four different heavy chains and four different light chains was enabled by employing microseed matrix screening (MMS). In initial screening, diffraction-quality crystals were obtained for only three Fabs, while many Fabs produced hits that required optimization. Application of MMS, using the initial screens and/or refinement screens, resulted in diffraction-quality crystals of these Fabs. Five Fabs that failed to give hits in the initial screen were crystallized by cross-seeding MMS followed by MMS optimization. The crystallization protocols and strategies that resulted in structure determination of all 16 Fabs are presented. These results illustrate the power of MMS and provide a basis for developing future strategies for macromolecular crystallization.

  13. Screening and Crystallization Plates for Manual and High-throughput Protein Crystal Growth

    Science.gov (United States)

    Thorne, Robert E. (Inventor); Berejnov, Viatcheslav (Inventor); Kalinin, Yevgeniy (Inventor)

    2010-01-01

    In one embodiment, a crystallization and screening plate comprises a plurality of cells open at a top and a bottom, a frame that defines the cells in the plate, and at least two films. The first film seals a top of the plate and the second film seals a bottom of the plate. At least one of the films is patterned to strongly pin the contact lines of drops dispensed onto it, fixing their position and shape. The present invention also includes methods and other devices for manual and high-throughput protein crystal growth.

  14. Stability of melt crystal growth under microgravity conditions

    Science.gov (United States)

    Tatarchenko, V. A.

    The conception of dynamic stability of melt crystal growth has been developed. The method based on the Lyapunov stability theory has been used to the study stability of crystallization by capillary shaping techniques including Czokhralsky, Stepanov, Kiropoulos, Verneuil and floating zone methods. Preliminary results of the stability analysis of crystallization by floating zone technique under microgravity conditions are presented here.

  15. Newborn Screening for Lysosomal Storage Disorders and Other Neuronopathic Conditions

    Science.gov (United States)

    Matern, Dietrich; Oglesbee, Devin; Tortorelli, Silvia

    2013-01-01

    Newborn screening (NBS) is a public health program aimed at identifying treatable conditions in presymptomatic newborns to avoid premature mortality, morbidity, and disabilities. Currently, every newborn in the Unites States is screened for at least 29 conditions where evidence suggests that early detection is possible and beneficial. With new or…

  16. Image Annotation and Database Mining to Create a Novel Screen for the Chemotype-Dependent Crystallization of HCV NS3 Protease

    Energy Technology Data Exchange (ETDEWEB)

    H Klei; K Kish; M Russo; S Michalczyk; M Cahn; J Tredup; C Chang; J Khan; E Baldwin

    2011-12-31

    An effective process for screening, imaging, and optimizing crystallization trials using a combination of external and internal hardware and software has been deployed. The combination of this infrastructure with a vast annotated crystallization database enables the creation of custom crystallization screening strategies. Because of the strong chemotype-dependent crystallization observed with HCV NS3 protease (HCVPr), this strategy was applied to a chemotype resistant to all prior crystallization efforts. The crystallization database was mined for ingredients used to generate earlier HCVPr/inhibitor co-crystals. A random screen was created from the most prolific ingredients. A previously untested combination of proven ingredients was identified that led to a successful crystallization condition for the resistant chemotype.

  17. Sound propagation over screened ground under upwind conditions

    DEFF Research Database (Denmark)

    Rasmussen, Karsten Bo

    1996-01-01

    in the frequency domain. The meteorological data representing the wind conditions have been determined by means of hot-wire anemometry in positions on both sides of the screen as well as directly over the screen. The theoretical model used for comparison is a hybrid approach. The sound field without a barrier......A screen on an absorbing ground is investigated experimentally and theoretically under upwind conditions. The experimental data are the result of scale model experiments in a 1:25 scale model. The sound propagation is measured using a triggered spark source with signal spectrum averaging...

  18. Biomolecular screening with encoded porous-silicon photonic crystals

    Science.gov (United States)

    Cunin, Frédérique; Schmedake, Thomas A.; Link, Jamie R.; Li, Yang Yang; Koh, Jennifer; Bhatia, Sangeeta N.; Sailor, Michael J.

    2002-09-01

    Strategies to encode or label small particles or beads for use in high-throughput screening and bioassay applications focus on either spatially differentiated, on-chip arrays or random distributions of encoded beads. Attempts to encode large numbers of polymeric, metallic or glass beads in random arrays or in fluid suspension have used a variety of entities to provide coded elements (bits)-fluorescent molecules, molecules with specific vibrational signatures, quantum dots, or discrete metallic layers. Here we report a method for optically encoding micrometre-sized nanostructured particles of porous silicon. We generate multilayered porous films in crystalline silicon using a periodic electrochemical etch. This results in photonic crystals with well-resolved and narrow optical reflectivity features, whose wavelengths are determined by the etching parameters. Millions of possible codes can be prepared this way. Micrometre-sized particles are then produced by ultrasonic fracture, mechanical grinding or by lithographic means. A simple antibody-based bioassay using fluorescently tagged proteins demonstrates the encoding strategy in biologically relevant media.

  19. Analysis of Boundary Conditions for Crystal Defect Atomistic Simulations

    Science.gov (United States)

    Ehrlacher, V.; Ortner, C.; Shapeev, A. V.

    2016-12-01

    Numerical simulations of crystal defects are necessarily restricted to finite computational domains, supplying artificial boundary conditions that emulate the effect of embedding the defect in an effectively infinite crystalline environment. This work develops a rigorous framework within which the accuracy of different types of boundary conditions can be precisely assessed. We formulate the equilibration of crystal defects as variational problems in a discrete energy space and establish qualitatively sharp regularity estimates for minimisers. Using this foundation we then present rigorous error estimates for (i) a truncation method (Dirichlet boundary conditions), (ii) periodic boundary conditions, (iii) boundary conditions from linear elasticity, and (iv) boundary conditions from nonlinear elasticity. Numerical results confirm the sharpness of the analysis.

  20. Low-amplitude Screening-photovoltaic Spatial Solitons in Biased Photovoltaic Photorefractive Crystals

    Institute of Scientific and Technical Information of China (English)

    HOU Chunfeng; LI Yan; YUAN Baohong; SUN Xiudong

    2000-01-01

    The low-amplitude spatial solitons in biased photovoltaic photorefractive crystals are investigated theoretically. The analytical solutions for both the bright and the dark low-amplitude screening-photovoltaic spatial solitons in photorefractive crystals are obtained. The expressions for the width of these solitons are given. The explicit expressions for the spatial deflection and angular deviation of the bright low-amplitude screening-photovoltaic spatial soliton are also presented by taking into account the effect of diffusion.

  1. Soap, science, and flat-screen TVs a history of liquid crystals

    CERN Document Server

    Dunmur, David

    2011-01-01

    The terms 'liquid crystal' or 'liquid crystal display' (LCD) are well-known in the context of flat-screen televisions, but the properties and history of liquid crystals are little understood. This book tells the story of liquid crystals, from their controversial discovery at the end of the nineteenth century, to their eventual acceptance as another state of matter to rank alongside gases, liquids and solids. As their story unfolds, the scientists involved and their works are put into illuminating broader socio-political contexts. In recent years, liquid crystals have had a major impact on the display industry, culminating in the now widely available flat-screen televisions; this development is described in detail over three chapters, and the basic science behind it is explained in simple terms accessible to a general reader. New applications of liquid crystals in materials, bio-systems, medicine and technology are also explained.

  2. Solvent screening and crystal habit of metformin hydrochloride

    Science.gov (United States)

    Benmessaoud, Ibtissem; Koutchoukali, Ouahiba; Bouhelassa, Mohamed; Nouar, Abderrahim; Veesler, Stéphane

    2016-10-01

    A multi-well setup with video-microscopy was used to study the influence of solvent on solubility, nucleation, and crystallization of an Active Pharmaceutical Ingredient (API): metformin hydrochloride (MET.HCl). Starting with 13 solvents covering a wide variety of polarity and proticity, we found 63 crystallization medium for MET.HCl solid generation: good solvents, good co-solvents and anti-solvent systems. For toxicological reasons, we limited the number of crystallization medium to 18: 3 good solvents (class 3), 3 good co-solvent systems and 12 anti-solvent systems. In order to study the influence of crystallization medium on nucleation temperature, crystal habit and polymorphism of MET.HCl, crystallization was studied by a cooling temperature method. Different crystal habits were observed by optical and scanning electron microscopies, and solid phase were characterized by X-ray powder diffraction, indicating that all the crystals correspond to the thermodynamic stable polymorphic form A of MET.HCl. Finally, the enthalpy of fusion and the melting temperature of MET.HCl were determined by DSC and confirmed the X-ray powder diffraction results.

  3. Setting up a liquid crystal phase screen to simulate atmospheric turbulence

    Science.gov (United States)

    Giles, Michael K.; Seward, Anthony J.; Vorontsov, Mikhail A.; Rha, Jungtae; Jimenez, Ray

    2000-11-01

    Phase screens are often used to simulate atmospheric turbulence in systems designed to test adaptive optics techniques. This paper presents the design and implementation of a dynamic phase screen using a simple and inexpensive twisted nematic liquid crystal display taken from a video projector and placed in a pupil plane. The details of the optical system layout, the system alignment procedure, and the operating parameters of the liquid crystal display are discussed. Examples of turbulence (having strength and statistics similar to measured values of atmospheric turbulence in a variety of scenarios) are written to the phase screen, and the effects of the turbulence on image quality are measured and presented.

  4. The case for indicator condition-guided HIV screening

    DEFF Research Database (Denmark)

    Lazarus, J V; Hoekstra, M; Raben, D

    2013-01-01

    One-half of the estimated 2.5 million people who now live with HIV in the World Health Organization (WHO) European Region are still diagnosed late. A central question is which clinical scenarios should trigger an HIV test recommendation in order to avoid late presentation. Drawing on the work...... of the HIV Indicator Diseases across Europe Study (HIDES), new guidance brings together in one place a list of the conditions that should result in an HIV screening recommendation....

  5. Lessons from high-throughput protein crystallization screening: 10 years of practical experience

    Science.gov (United States)

    JR, Luft; EH, Snell; GT, DeTitta

    2011-01-01

    Introduction X-ray crystallography provides the majority of our structural biological knowledge at a molecular level and in terms of pharmaceutical design is a valuable tool to accelerate discovery. It is the premier technique in the field, but its usefulness is significantly limited by the need to grow well-diffracting crystals. It is for this reason that high-throughput crystallization has become a key technology that has matured over the past 10 years through the field of structural genomics. Areas covered The authors describe their experiences in high-throughput crystallization screening in the context of structural genomics and the general biomedical community. They focus on the lessons learnt from the operation of a high-throughput crystallization screening laboratory, which to date has screened over 12,500 biological macromolecules. They also describe the approaches taken to maximize the success while minimizing the effort. Through this, the authors hope that the reader will gain an insight into the efficient design of a laboratory and protocols to accomplish high-throughput crystallization on a single-, multiuser-laboratory or industrial scale. Expert Opinion High-throughput crystallization screening is readily available but, despite the power of the crystallographic technique, getting crystals is still not a solved problem. High-throughput approaches can help when used skillfully; however, they still require human input in the detailed analysis and interpretation of results to be more successful. PMID:22646073

  6. 3D-Printed High-Density Droplet Array Chip for Miniaturized Protein Crystallization Screening under Vapor Diffusion Mode.

    Science.gov (United States)

    Liang, Yi-Ran; Zhu, Li-Na; Gao, Jie; Zhao, Hong-Xia; Zhu, Ying; Ye, Sheng; Fang, Qun

    2017-04-05

    Here we describe the combination of three-dimensional (3D) printed chip and automated microfluidic droplet-based screening techniques for achieving massively parallel, nanoliter-scale protein crystallization screening under vapor diffusion mode. We fabricated high-density microwell array chips for sitting-drop vapor diffusion crystallization utilizing the advantage of the 3D-printing technique in producing high-aspect-ratio chips. To overcome the obstacle of 3D-printed microchips in performing long-term reactions caused by their porousness and gas permeability properties in chip body, we developed a two-step postprocessing method, including paraffin filling and parylene coating, to achieve high sealability and stability. We also developed a simple method especially suitable for controlling the vapor diffusion speed of nanoliter-scale droplets by changing the layer thickness of covering oil. With the above methods, 84 tests of nanoliter-scale protein crystallization under vapor diffusion mode were successfully achieved in the 7 × 12 droplet array chip with a protein consumption of 10 nL for each test, which is 20-100 times lower than that in the conventional large-volume screening system. Such a nanoliter-scale vapor diffusion system was applied to two model proteins with commercial precipitants and displayed advantages over that under microbatch mode. It identified more crystallization conditions, especially for the protein samples with lower concentrations.

  7. Cardiotocography (CTG as the screening method of fetal condition assessment

    Directory of Open Access Journals (Sweden)

    V. Zulčić-Nakić

    2007-02-01

    Full Text Available A basic function of fetal monitoring is an analysis of fetal cardiac action. Cardiotocography (CTG cannot provide all necessary information for assessment of the fetal condition as it is not sufficiently reliable and gives a large number of false positive results that increase the number of cesarean sections. An objective of this work was to establish CTG reliability as a method for assessment of intrapartal fetal condition. Based on CTG parameters (baseline fetal heart rate, fetal heart rate variability, oscillations and decelerations 100 pathological CTG records, collected at Obstetrics and Gynecology Department of the Tuzla University Clinic Hospital from 01.12.2004 to 05.08.2005 were identified. Using binomial distribution they were classified as non-pathological (indicating absence of asphyxia and pathological (indicating possible presence of asphyxia. After the delivery the condition of newborns was assessed according to the Apgar score. Based on comparison between certain pathological parametres of CTG records and newborns’ conditions at birth the results indicated high positive predictive values whereas sensitivity and accuracy were low. Apgar score 1. from 7 upwards was given to 96 (96% newborns whereas Apgar score 2 from 7 upwards was given to all the newborns with previous pathological CTG records. Results have confirmed that CTG can be used only as a screening method for assessment of intrapartal fetal condition.

  8. Overview of electron crystallography of membrane proteins: crystallization and screening strategies using negative stain electron microscopy.

    Science.gov (United States)

    Nannenga, Brent L; Iadanza, Matthew G; Vollmar, Breanna S; Gonen, Tamir

    2013-01-01

    Electron cryomicroscopy, or cryoEM, is an emerging technique for studying the three-dimensional structures of proteins and large macromolecular machines. Electron crystallography is a branch of cryoEM in which structures of proteins can be studied at resolutions that rival those achieved by X-ray crystallography. Electron crystallography employs two-dimensional crystals of a membrane protein embedded within a lipid bilayer. The key to a successful electron crystallographic experiment is the crystallization, or reconstitution, of the protein of interest. This unit describes ways in which protein can be expressed, purified, and reconstituted into well-ordered two-dimensional crystals. A protocol is also provided for negative stain electron microscopy as a tool for screening crystallization trials. When large and well-ordered crystals are obtained, the structures of both protein and its surrounding membrane can be determined to atomic resolution.

  9. Monoclinic deformation of calcite crystals at ambient conditions

    Science.gov (United States)

    Przeniosło, R.; Fabrykiewicz, P.; Sosnowska, I.

    2016-09-01

    High resolution synchrotron radiation powder diffraction shows that the average crystal structure of calcite at ambient conditions is described with the trigonal space group R 3 bar c but there is a systematic hkl-dependent Bragg peak broadening. A modelling of this anisotropic peak broadening with the microstrain model from Stephens (1999) [15] is presented. The observed lattice parameters' correlations can be described by assuming a monoclinic-type deformation of calcite crystallites. A quantitative model of this monoclinic deformation observed at ambient conditions is described with the space group C 2 / c . The monoclinic unit cell suggested at ambient conditions is related with the monoclinic unit cell reported in calcite at high pressure (Merrill and Bassett (1975) [10]).

  10. An experimental screen for quinoline/fumaric acid salts and co-crystals

    DEFF Research Database (Denmark)

    Beko, S. L.; Schmidt, M. U.; Bond, A. D.

    2012-01-01

    An experimental screen has been carried out for salts and co-crystals of quinoline (C9H7N) and fumaric acid (C4H4O4), including solution-based co-crystallisation from a variety of solvents, solvent-assisted and solvent-free co-grinding, and direct co-crystallisation of the starting materials...

  11. 42 CFR 410.37 - Colorectal cancer screening tests: Conditions for and limitations on coverage.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Colorectal cancer screening tests: Conditions for...) BENEFITS Medical and Other Health Services § 410.37 Colorectal cancer screening tests: Conditions for and...) Colorectal cancer screening tests means any of the following procedures furnished to an individual for the...

  12. Operation condition for continuous anti-solvent crystallization of CBZ-SAC cocrystal considering deposition risk of undesired crystals

    Science.gov (United States)

    Nishimaru, Momoko; Nakasa, Miku; Kudo, Shoji; Takiyama, Hiroshi

    2017-07-01

    Crystallization operation of cocrystal production has deposition risk of undesired crystals. Simultaneously, continuous manufacturing processes are focused on. In this study, conditions for continuous cocrystallization considering risk reduction of undesired crystals deposition were investigated on the view point of thermodynamics and kinetics. The anti-solvent cocrystallization was carried out in four-component system of carbamazepine, saccharin, methanol and water. From the preliminary batch experiment, the relationships among undesired crystal deposition, solution composition decided by mixing ratio of solutions, and residence time for the crystals were considered, and then the conditions of continuous experiment were decided. Under these conditions, the continuous experiment was carried out. The XRD patterns of obtained crystals in the continuous experiment showed that desired cocrystals were obtained without undesired crystals. This experimental result was evaluated by using multi-component phase diagrams from the view point of the operation point's movement. From the evaluation, it was found that there is a certain operation condition which the operation point is fixed with time in the specific domain without the deposition risk of undesired single component crystals. It means the possibility of continuous production of cocrystals without deposition risk of undesired crystals was confirmed by using multi-component phase diagrams.

  13. Bright-Dark Vector Screening-Photovoltaic Spatial Solitons in Biased Photorefractive-Photovoltaic Crystals

    Institute of Scientific and Technical Information of China (English)

    卢克清; 钱士雄; 窦春升; 吴振森

    2002-01-01

    We show that the vector beam evolution equations in properly oriented biased photorefractive-photovoltaic crystals can exhibit bright-dark vector solitons, which result from both the bulk photovoltaic effect and the spatially non-uniform screening of the external bias field. By adjusting the polarization of the incident beam to obtain the appropriate ratio of two orthogonal components, these vector solitons can be established. When the bulk photovoltaic effect is negligible, these vector solitons are bright-dark vector screening solitons. When the external field is absent, these vector solitons predict bright-dark vector photovoltaic solitons.

  14. Expanding pH screening space using multiple droplets with secondary buffers for protein crystallization

    Science.gov (United States)

    Zhang, Chen-Yan; Dong, Chen; Lu, Xiao-Li; Wang, Bei; He, Tian-Yuan; Yang, Rui-Zeng; Lin, Hua-Long; Yang, Xue-Zhou; Yin, Da-Chuan

    2017-04-01

    We have proposed a rational strategy for selecting a suitable pH of protein solution based on protein biochemical properties. However, it is difficult to use this strategy for biochemical properties unknown proteins. In this paper, a simpler and faster pH buffer strategy was proposed. An additional pH-controlling buffer was added to crystallization droplet mixed with protein solution and commercial crystallization reagents to adjust its pH. The results revealed that protein crystallization success rates were enhanced by this strategy due to expansion of the pH screening space, which was closely related with protein solubility. Thus, the possibility of reaching supersaturation was increased by using this strategy.

  15. Developmental Screening Using the Ages and Stages Questionnaire: Standardized versus Real-World Conditions

    Science.gov (United States)

    San Antonio, Marianne C.; Fenick, Ada M.; Shabanova, Veronika; Leventhal, John M.; Weitzman, Carol C.

    2014-01-01

    Developmental screens are often used in nonstandardized conditions, such as pediatric waiting rooms, despite validation under standardized conditions. We examined the reproducibility of the Ages and Stages Questionnaire (ASQ), a developmental screening instrument commonly used in pediatric practices, under standardized versus nonstandardized…

  16. 42 CFR 410.23 - Screening for glaucoma: Conditions for and limitations on coverage.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Screening for glaucoma: Conditions for and... Medical and Other Health Services § 410.23 Screening for glaucoma: Conditions for and limitations on... mellitus. (ii) Individual with a family history of glaucoma. (iii) African-Americans age 50 and over....

  17. Efficacy of crystallization test for screening of oral squamous cell carcinoma with clinico-pathological correlation

    Directory of Open Access Journals (Sweden)

    Sachin C Sarode

    2013-01-01

    Full Text Available Aim: To determine the efficacy of crystallization test for screening oral squamous cell carcinoma (OSCC with clinico-pathologic correlation. Materials and Methods: Fifty patients of OSCC and 30 healthy individuals were selected. One drop of blood was collected into 1 cc of doubled distilled water at room temperature to give a final dilution of 6% hemolyzed blood. 0.1 to 0.2 cc of blood sample was then subjected to crystallization test using 10% cupric chloride solution. Results: In healthy control group, the typical pattern was an eccentrically placed center of gravity with needles arranged in radiating fashion, while in OSCC group, there was ′transverse form′ (TF formation. The sensitivity and specificity of this test was found to be 96% and 96.66%, respectively. The positive and negative predictive values were found to be 97.96% and 98.55%, respectively. The mean TF frequency was found to be increasing from grade I (3.20 ± 1.5% to grade II (653 ± 2.23% and difference was statistically significant (P = 0.0001. However, there was no correlation between mean TF frequency and TNM stages of OSCC. Conclusion: Crystallization test is a simple, reliable, economical, less time-consuming, and less invasive screening procedure, which can be used for early detection of OSCC.

  18. Screening of multicomponent crystals of L-tryptophan with three isomers of pyridinedicarboxylic acids

    Science.gov (United States)

    Das, Babulal

    2016-08-01

    Multicomponent crystallization of L-tryptophan with three different isomers of pyridinedicarboxylic acids, namely, 2,3-pyridinedicarboxylic acid (2,3-PDA), 2,5-pyridinedicarboxylic acid (2,5-PDA) and 2,6-pyridinedicarboxylic acid (2,6-PDA), were screened using conventional solution cocrystallization technique. Whereas the new phases derived from the amino acid with 2,3-PDA or 2,5-PDA were analyzed using powder X-ray diffraction and thermal analysis techniques, the crystalline phase synthesized from 2,6-substituted isomer was further characterized by single crystal X-ray diffraction. Structural analysis revealed that the amino acid exists in the zwitterionic form interacting with the neutral 2,6-PDA by strong intermolecular hydrogen bonding. The components in the co-crystal self-assemble leading to a three dimensional hydrogen bonded closed packed network structure. Isothermal calorimetric titration showed that among the three isomers, 2,6-PDA showed relatively strong binding interaction towards the amino acid in water at 298 K. All the crystals exhibit marginal quenching of fluorescence properties of L-tryptophan in the solid state.

  19. Modifying culture conditions in chemical library screening identifies alternative inhibitors of mycobacteria.

    Science.gov (United States)

    Miller, Christopher H; Nisa, Shahista; Dempsey, Sandi; Jack, Cameron; O'Toole, Ronan

    2009-12-01

    In this study, application of a dual absorbance/fluorescence assay to a chemical library screen identified several previously unknown inhibitors of mycobacteria. In addition, growth conditions had a significant effect on the activity profile of the library. Some inhibitors such as Se-methylselenocysteine were detected only when screening was performed under nutrient-limited culture conditions as opposed to nutrient-rich culture conditions. We propose that multiple culture condition library screening is required for complete inhibitory profiling and for maximal antimycobacterial compound detection.

  20. Experimental setup for rapid crystallization using favoured chemical potential and hydrodynamic conditions

    Indian Academy of Sciences (India)

    V K Dixit; B V Rodrigues; H L Bhat

    2001-10-01

    The rapid crystallization of KH2PO4 (KDP) from solution is demonstrated at a rate up to ≈7.5 mm/day along [100] and 22 mm/day along [001] in a crystallizer of 5 l capacity, using accelerated crucible rotation technique (ACRT) and simulated platform geometry for controlling the hydrodynamic conditions. On an experimental basis we have grown the crystals up to 40 × 43 × 66 mm3 size in about 3 days. Comparative analysis of the main structural and optical properties of crystals grown by conventional and rapid crystallization technique, is discussed.

  1. Systematic screening for unsafe driving due to medical conditions: Still debatable

    Directory of Open Access Journals (Sweden)

    Lagarde Emmanuel

    2008-01-01

    Full Text Available Abstract Background Assessing people's ability to drive has become a public health concern in most industrialized countries. Although age itself is not a predictive factor of an increased risk for dangerous driving, the prevalence of medical conditions that may impair driving increases with age. Because the implementation of a screening for unsafe driving due to medical conditions is a public health issue, its usefulness should be judged using standardised criteria already proposed for screening for chronic disease. The aim of this paper is to propose standardised criteria suitable to assess the scientific validity of screening for unsafe driving due to medical conditions, and identify potential issues to be clarified before screening can be implemented and effective. Discussion Using criteria developed for screening for chronic diseases and published studies on driving with medical conditions, we specify six criteria to judge the opportunity of screening for unsafe driving due to medical conditions. This adaptation was needed because of the complexity of the natural history of medical conditions and their potential consequences on driving and road safety. We then illustrate that published studies pleading for or against screening for unsafe driving due to medical conditions fail to provide the needed documentation. Individual criteria were mentioned in 3 to 72% of 36 papers pleading for or against screening. Quantitative estimates of relevant indicators were provided in at most 42% of papers, and some data, such as the definition of an appropriate unsafe driving period were never provided. Summary The standardised framework described in this paper provides a template for assessing the effectiveness (or lack of effectiveness of proposed measures for screening for unsafe driving due to medical conditions. Even if most criteria were mentioned in the published literature pleading for or against such a screening, the failure to find quantitative and

  2. Crystal Habits of Itraconazole Microcrystals: Unusual Isomorphic Intergrowths Induced via Tuning Recrystallization Conditions.

    Science.gov (United States)

    Mugheirbi, Naila A; Tajber, Lidia

    2015-09-01

    The external appearance of a crystal of active pharmaceutical ingredient (API), usually referred to as a crystal habit, has a substantial impact on the API's physicochemical and physiochemical properties and, subsequently, its pharmaceutical performance. In this work, we investigate the role of different parameters of antisolvent crystallization impacting on the itraconazole (ITR) crystal habit and how this crystal habit manipulation, including crystal intergrowth, can affect crystal interactions with water molecules. Three distinct isomorphic crystal habits of ITR, a twinned blade-shaped (CHtw), a plate-shaped (CHpl), and a flat sheet-shaped with dendritic ends (CHsh), were obtained by controlling crystallization conditions. A liquid-liquid crystalline phase separation was observed as an intermediate stage preceding crystal growth. The March-Dollase parameter was used as a quantitative description of the preferred orientation, where CHsh exhibited the highest preferred orientation. The three crystal habits were evaluated for their wettability and water vapor distribution, at 37 °C, using the Young-Nelson fitting model. CHtw crystals sorbed a statistically significantly higher amount of water than CHpl and CHsh, which was attributed to the presence of crystal defects due to the twinning boundary. On the other hand, the amount of water adsorbed on the surface of CHpl and CHsh crystals was comparable and it was about twice that adsorbed on CHtw crystals. This was related to the abundance of hydrophilic chemical functionalities on the (010) facet of CHpl and CHsh as supported by the full interaction map carried out using Mercury software. This study expands investigations of the impact of crystal habit manipulation on API's functional properties beyond the well-known solubility improvement approaches.

  3. High-throughput platform for design and screening of peptides as inhibitors of calcium oxalate monohydrate crystallization

    Science.gov (United States)

    Farmanesh, Sahar; Chung, Jihae; Chandra, Divya; Sosa, Ricardo D.; Karande, Pankaj; Rimer, Jeffrey D.

    2013-06-01

    Crystal growth modifiers present a versatile tool for controlling crystal shape and size. Our work described here focuses on the design and screening of short peptides as inhibitors of calcium oxalate monohydrate (COM) crystals using high-throughput approaches. We designed a small library of 13 peptides containing Ala and Asp amino acids arranged in varying sequences that mimic ubiquitous motifs in natural calcium-binding proteins. Peptides were screened using a quick assay to measure their efficacy for inhibiting COM crystallization. Our results show that subtle variations in the placement of Ala and Asp residues in the peptide sequence can have a profound effect on their inhibition potential. We were able to discover peptide sequences that inhibit COM crystallization more effectively than some of the well-known COM inhibitors, such as citrate. Our results also demonstrate that peptides can be engineered to bind to specific faces of COM crystals. Peptide sequences identified in this work are promising candidates for further development as therapies for biomineral-related diseases, such as kidney stone disease. Collectively, our work establishes new paradigms for the design, synthesis, and screening of peptides for controlling crystal habit with the potential to impact a variety of fields, including drug discovery, advanced materials, catalysis and separations.

  4. Analysis of switching conditions of chalcogenide alloys during crystallization

    Institute of Scientific and Technical Information of China (English)

    Wanhua Yu; C.D. Wright

    2006-01-01

    To understand the principle and limitation of chalcogenide alloy Ge2Sb2Te5 (GST) in solid-state memory devices during crystallization, it was necessary to develop a physically realistic model that could reflect the electrical and thermal properties of these media. A novel comprehensive numerical model has been developed for simulating these memory devices, which describes the electrical and thermal behavior using the solution of the nonlinear, time-dependent electrical and heat conduction equation. The finite-difference-time-domain technique was adopted to compute the electrical field and heat distribution in the device. Several contributing factors that affect the crystallization switching process such as the geometry of the GST layer, temperature and electric field dependency of the electrical conductivity have been discussed. The results of the simulations were then used to provide critical guidelines for fabrication and optimization of the device performance.

  5. Measurement and analysis of the mannitol partition coefficient in sucrose crystallization under simulated industrial conditions

    Science.gov (United States)

    Mannitol is a major deterioration product of Leuconstoc mesenteroides bacterial deterioration of both sugarcane and sugar beet. The effect of crystallization conditions on the mannitol partition coefficient (Keff) between impure sucrose syrup and crystal has been investigated in a batch laboratory c...

  6. Optimization of Screening Method for Feed Nutrition and Processing Conditions

    Institute of Scientific and Technical Information of China (English)

    YangYun-qing; WangYi-tong; 等

    1999-01-01

    On the basis of regressional relationship between nutritional indexes and technological conditions,when confronted with feed quality that contains multiple nutritional indexes,a comprehensive equation of evaluating feed quality was developed by using fuzzy mathematical method at first in this study,and then the optimum technological conditions were established by introduction of statistical frequency analysis method pursuant to the comprehensive evaluating equation mentioned above compared with conventional multi-aim nonlinear programming,this method can lead to easy solutions,and also can make adjustment of the importance of nutritional indexes to feed quality according to practical considerations.An example was given of soybean extruding to show how the method worked.

  7. Optimization of Screening Method for Feed Nutrition and Processing Conditions

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    On the basis of regressional relationship between nutritional indexes and technological conditions, when confronted with feed quality that contains multiple nutritional indexes ,a comprehensive equation of evaluating feed quality was developed by using fuzzy mathematical method at first in this study,and then the optimum technological conditions were established by introduction of statistical frequency analysis method pursuant to the comprehensive evaluating equation mentioned above compared with conventional multi-aim nonlinear programming,this method can lead to easy solutions ,and also can make adjustment of the importance of nu- tritional indexes to feed quality according to practical considerations. An example was given of soybean ex- truding to show how the method worked.

  8. Decision-making and cancer screening: a qualitative study of older adults with multiple chronic conditions.

    Science.gov (United States)

    Gross, Cary P; Fried, Terri R; Tinetti, Mary E; Ross, Joseph S; Genao, Inginia; Hossain, Sabina; Wolf, Elizabeth; Lewis, Carmen L

    2015-03-01

    To understand how older persons with multiple chronic conditions (MCC) approach decisions about cancer screening. We conducted interviews with adults >65 years old with at least two chronic conditions who were taking ≥five medications daily. Patients were first asked how age and multimorbidity influence their cancer screening decisions. After showing them an educational prompt that explained the relationship between life expectancy and the benefits of cancer screening, respondents were then asked about screening in the context of specific health scenarios. Using grounded theory, three independent readers coded responses for salient themes. Sample size was determined by thematic saturation. Most respondents (26 of 28) initially indicated that their overall health or medical conditions do not influence their cancer screening decisions. After viewing the educational prompt, respondents described two broad approaches to cancer screening in the setting of increasing age or multi-morbidity. The first was a "benefits versus harms" approach in which participants weighed direct health benefits (e.g. reducing cancer incidence or mortality) and harms (e.g. complications or inconvenience). The second was a heuristic approach. Some heuristics favored screening, such as a persistent belief in unspecified benefits from screening, value of knowledge about cancer status, and not wanting to "give up", whereas other heuristics discouraged screening, such as fatalism or a reluctance to learn about their cancer status. When considering cancer screening, some older persons with MCC employ heuristics which circumvent the traditional quantitative comparison of risks and benefits, providing an important challenge to informed decision making. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. High-throughput identification of purification conditions leads to preliminary crystallization conditions for three inner membrane proteins.

    Science.gov (United States)

    Gabrielsen, Mads; Kroner, Frank; Black, Isobel; Isaacs, Neil W; Roe, Andrew J; McLuskey, Karen

    2011-01-01

    An important factor in the crystallization, and subsequent structural determination, of integral membrane proteins is the ability to produce a stable and monodisperse solution of the protein. Obtaining the correct purification detergent to achieve this can be laborious and is often serendipitous. In this study, high-throughput methods are used to analyze the suitability of eight different detergents on the stability of 12 inner transmembrane proteins from Escherichia coli. The best results obtained from the small-scale experiments were scaled up, the aggregation state of the proteins assessed, and all monodisperse protein solutions entered into crystallization trials. This resulted in preliminary crystallization hits for three inner membrane proteins: XylH, PgpB and YjdL and this study reports the methods, purification procedures and crystallization conditions used to achieve this.

  10. Effect of UV Laser Conditioning on the Structure of KDP Crystal

    Directory of Open Access Journals (Sweden)

    Decheng Guo

    2014-01-01

    Full Text Available Multiparametric raster scanning experiments for KDP crystals are carried out to study the laser conditioning efficiency as a function of laser fluence, fluence step, and pulse sequence by using ultraviolet (UV laser irradiation with pulse duration of approximately 7 ns. It indicates that damage resistance of KDP can be enhanced after conditioning process. And laser conditioning efficiency depends on the maximal fluence which is below the damage threshold. Raman spectra and photothermal absorption have also been studied on KDP crystals before and after multiparametric laser conditioning. Photothermal absorption data reveal that absorbance of conditioned KDP crystal decreases with the increase of laser fluence and the damage threshold of low absorption area is higher. Raman analysis reveals that the effectiveness of laser conditioning relies mainly on the individual mode of PO4 molecule.

  11. Salicylamide cocrystals: screening, crystal structure, sublimation thermodynamics, dissolution, and solid-state DFT calculations.

    Science.gov (United States)

    Manin, Alex N; Voronin, Alexander P; Manin, Nikolay G; Vener, Mikhail V; Shishkina, Anastasia V; Lermontov, Anatoly S; Perlovich, German L

    2014-06-19

    A new cocrystal of 2-hydroxybenzamide (A) with 4-acetamidobenzoic acid (B) has been obtained by the DSC screening method. Thermophysical analysis of the aggregate [A:B] has been conducted and a fusion diagram has been plotted. Cocrystal formation from melts was studied by using thermomicroscopy. A cocrystal single-crystal was grown and its crystal structure was determined. The pattern of noncovalent interactions has been quantified using the solid-state DFT computations coupled with the Bader analysis of the periodic electron density. The sublimation processes of A-B cocrystal have been studied and its thermodynamic functions have been calculated. The classical method of substance transfer by inert gas-carrier was chosen to investigate sublimation processes experimentally. The lattice energy is found to be 143 ± 4 kJ/mol. It is lower than the sum of the corresponding values of the cocrystal pure components. The theoretical value of the lattice energy, 156 kJ/mol, is in reasonable agreement with the experimental one. A ternary phase diagram of solubility (A-B-ethanol) has been plotted and the areas with solutions for growing thermodynamically stable cocrystals have been determined.

  12. Public support for neonatal screening for Pompe disease, a broad-phenotype condition

    Directory of Open Access Journals (Sweden)

    Weinreich Stephanie

    2012-03-01

    Full Text Available Abstract Background Neonatal screening for Pompe disease has been introduced in Taiwan and a few U.S. states, while other jurisdictions including some European countries are piloting or considering this screening. First-tier screening flags both classic infantile and late-onset Pompe disease, which challenges current screening criteria. Previously, advocacy groups have sometimes supported expanded neonatal screening more than professional experts, while neutral citizens' views were unknown. This study aimed to measure support for neonatal screening for Pompe disease in the general public and to compare it to support among (parents of patients with this condition. The study was done in the Netherlands, where newborns are not currently screened for Pompe disease. Newborn screening is not mandatory in the Netherlands but current uptake is almost universal. Methods A consumer panel (neutral group and (parents of patients with Pompe disease (Pompe group were sent information and a questionnaire. Responses were analyzed of 555 neutral and 58 Pompe-experienced informants who had demonstrated sufficient understanding. Results 87% of the neutral group and 88% of the Pompe group supported the introduction of screening (95% CI of difference -10 to 7%. The groups were similar in their moral reasoning about screening and acceptance of false positives, but the Pompe-experienced group expected greater benefit from neonatal detection of late-onset disease. Multivariate regression analysis controlling for demographics confirmed that approval of the introduction of screening was independent of having (a child with Pompe disease. Furthermore, respondents with university education, regardless of whether they have (a child with Pompe disease, were more likely to be reluctant about the introduction of screening than those with less education, OR for approval 0.29 (95% CI 0.18 to 0.49, p Conclusions This survey suggests a rather high level of support for newborn

  13. Debye screening under non-equilibrium plasma conditions

    Science.gov (United States)

    Fahr, Hans J.; Heyl, M.

    2016-05-01

    As has been revealed in a number of more recent astrophysical papers, in most of the tenuous space plasmas Maxwellian distribution functions cannot be expected for ions or electrons because of the lack of efficient relaxation processes. Many of the classical characteristics of plasmas, such as plasma frequency or Debye length, are calculated on the basis of the assumption, however, that Maxwellians prevail, which under most of the relevant astrophysical plasma conditions is not the case. We here therefore consider this specific problem of Debye shieldings of single charges in a plasma for the case of prevailing non-equilibrium distribution functions for ions and electrons. As typical non-equilibrium functions, so-called Kappa functions were considered with clear preference, and we therefore study here the Debye shielding in a plasma with Kappa-distributed electrons and ions. We show that the so-called Debye shielding increases with increasing extent of the high-velocity tail of the electron distribution function, or in other words, with lower Kappa index of the underlying Kappa function. In our calculations we demonstrate that the Debye lengths become enlarged by about a factor of 10 with respect to its classically expexted value if highly suprathermal electron distributions prevail with Kappa indices close to 1.5.

  14. Utilization of oriented crystal growth for screening of aromatic carboxylic acids cocrystallization with urea

    Science.gov (United States)

    Przybyłek, Maciej; Ziółkowska, Dorota; Kobierski, Mirosław; Mroczyńska, Karina; Cysewski, Piotr

    2016-01-01

    The possibility of molecular complex formation in the solid state of urea with benzoic acid analogues was measured directly on the crystallite films deposited on the glass surface using powder X-ray diffractometry (PXRD). Obtained solid mixtures were also analyzed using Fourier transform infrared spectroscopy (FTIR). The simple droplet evaporation method was found to be efficient, robust, fast and cost-preserving approach for first stage cocrystal screening. Additionally, the application of orientation effect to cocrystal screening simplifies the analysis due to damping of majority of diffraction signals coming from coformers. During validation phase the proposed approach successfully reproduced both positive cases of cocrystallization (urea:salicylic acid and urea:4-hydroxy benzoic acid) as well as pairs of co-formers immiscible in the solid state (urea:benzoic acid and urea:acetylsalicylic acids). Based on validated approach new cocrystals of urea were identified in complexes with 3-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid and 3,5-dihydroxybenzoic acid. In all cases formation of multicomponent crystal phase was confirmed by the appearance of new reflexes on the diffraction patterns and FTIR absorption band shifts of O-H and N-H groups.

  15. Modeling of Macroscopic/Microscopic Transport and Growth Phenomena in Zeolite Crystal Solutions Under Microgravity Conditions

    Science.gov (United States)

    Gatsonis, Nikos A.; Alexandrou, Andreas; Shi, Hui; Ongewe, Bernard; Sacco, Albert, Jr.

    1999-01-01

    Crystals grown from liquid solutions have important industrial applications. Zeolites, for instance, a class of crystalline aluminosilicate materials, form the backbone of the chemical process industry worldwide, as they are used as adsorbents and catalysts. Many of the phenomena associated with crystal growth processes are not well understood due to complex microscopic and macroscopic interactions. Microgravity could help elucidate these phenomena and allow the control of defect locations, concentration, as well as size of crystals. Microgravity in an orbiting spacecraft could help isolate the possible effects of natural convection (which affects defect formation) and minimize sedimentation. In addition, crystals will stay essentially suspended in the nutrient pool under a diffusion-limited growth condition. This is expected to promote larger crystals by allowing a longer residence time in a high-concentration nutrient field. Among other factors, the crystal size distribution depends on the nucleation rate and crystallization. These two are also related to the "gel" polymerization/depolymerization rate. Macroscopic bulk mass and flow transport and especially gravity, force the crystals down to the bottom of the reactor, thus forming a sedimentation layer. In this layer, the growth rate of the crystals slows down as crystals compete for a limited amount of nutrients. The macroscopic transport phenomena under certain conditions can, however, enhance the nutrient supply and therefore, accelerate crystal growth. Several zeolite experiments have been performed in space with mixed results. The results from our laboratory have indicated an enhancement in size of 30 to 70 percent compared to the best ground based controls, and a reduction of lattice defects in many of the space grown crystals. Such experiments are difficult to interpret, and cannot be easily used to derive empirical or other laws since many physical parameters are simultaneously involved in the process

  16. Solution based synthesis of simple fcc Si nano-crystals under ambient conditions.

    Science.gov (United States)

    Balcı, Mustafa H; Sæterli, Ragnhild; Maria, Jerome; Lindgren, Mikael; Holmestad, Randi; Grande, Tor; Einarsrud, Mari-Ann

    2013-02-28

    We demonstrate for the first time that simple face-centered cubic (fcc) silicon nano-crystals can be produced by a solution based bottom-up synthesis route under ambient conditions. Simple fcc Si nano-crystals (2-7 nm) were prepared at room temperature by using sodium cyclopentadienide as a reducing agent for silicon tetrachloride. Photoluminescence emission at 550 nm was observed for the fcc silicon nano-crystals upon excitation at 340 nm, indicating that fcc Si nano-crystals were exhibiting direct bandgap like semiconductor properties with very fast radiative recombination rates. The new synthesis route makes possible the production and study of simple fcc polymorphs of Si nano-crystals with an easy alteration of surface termination groups.

  17. Crystal habit and growth conditions of brushite, CaHPO 4 ṡ 2H 2O

    Science.gov (United States)

    Abbona, F.; Christensson, F.; Angela, M. Franchini; Madsen, H. E. Lundager

    1993-08-01

    Brushite, a polar compound, has been grown from aqueous solutions at 25 and 40°C in a large interval of concentrations, pH and supersaturations. The great variety of morphologies (aggregates, twins, regular and irregular crystals) are described and related to the growth conditions. The polar habit of brushite appears only under definite conditions. Four types of twins have been found, one of them occuring only at 40°C. The experimental crystal habit is compared to the theoretical crystal habit derived from the structure by the periodic bond chain (PBC) method. The form {111}, which has a high frequency, shows morphological instability due to its S character. The role played by the wrong incorporation of HPO 2-4 in the kinks in forming the [010] twins and the irregular crystals is pointed out. The growth mechanisms of the most important faces are also discussed.

  18. Measurement and analysis of the mannitol partition coefficient in sucrose crystallization under simulated industrial conditions.

    Science.gov (United States)

    Eggleston, Gillian; Yen, Jenny Wu Tiu; Alexander, Clay; Gober, Jessica

    2012-07-01

    Mannitol is a major deterioration product of Leuconstoc mesenteroides bacterial metabolism of sucrose and fructose from both sugarcane and sugar beet. The effect of crystallization conditions on the mannitol partition coefficient (K(eff)) between impure sucrose syrup and crystal has been investigated in a batch laboratory crystallizer and a batch pilot plant-scale vacuum pan. Laboratory crystallization was operated at 65.5°C (150°F), 60.0°C (140°F), and 51.7°C (125°F) with a 78.0 Brix (% refractometric dissolved solids) pure sucrose syrup containing 0%, 0.1%, 0.2%, 1.0%, 2.0%, 3.0%, and 10% (at 65.5°C only) mannitol on a Brix basis. Produced mother liquor and crystals were separated by centrifugation and their mannitol contents measured by ion chromatography with integrated pulsed amperometric detection (IC-IPAD). The extent of mannitol partitioning into the crystals depended strongly on the mannitol concentration in the feed syrup and, to a lesser extent, the crystallization temperature. At 65.5 and 60.0°C, the K(eff) varied from ~0.4% to 3.0% with 0.2% to 3.0% mannitol in the feed syrup, respectively. The mannitol K(eff) was lower than that reported for dextran (~9-10% K(eff)), another product of Leuconstoc deterioration, under similar sucrose crystal growth conditions. At 10% mannitol concentration in the syrup at 65.5°C, co-crystallization of mannitol with sucrose occurred and the crystal growth rate was greatly impeded. In both laboratory and pilot plant crystallizations (95.7% purity; 78.0 Brix; 65.5°C), mannitol tended to cause conglomerates to form, which became progressively worse with increased mannitol syrup concentration. At the 3% mannitol concentration, crystallization at both the laboratory and pilot plant scales was more difficult. Mannitol incorporation into the sucrose crystal results mostly from liquid syrup inclusions but adsorption onto the crystal surface may play a minor role at lower mannitol concentrations.

  19. Screening of Strains Producing Alkaline Protease from Soil and Study on the Conditions for Enzyme Production

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The aim was to screen strains producing alkaline protease from soil and study the conditions for enzyme production.[Method] Eight strains producing alkaline protease were isolated from soil through plate isolation,and the ability of enzyme production was measured by filter paper and Folin-phenol method.The strain with the strongest ability of enzyme production was screened as a candidate strain,then the factors influencing the ability of enzyme production was studied,finally the conditions for e...

  20. Evaluation of the Crystallization Tendency of Commercially Available Amorphous Tacrolimus Formulations Exposed to Different Stress Conditions.

    Science.gov (United States)

    Trasi, Niraj S; Purohit, Hitesh S; Taylor, Lynne S

    2017-07-07

    Tacrolimus, an immunosuppressant, is a poorly water soluble compound whereby the commercially available capsule formulations contain the drug in amorphous form. The goal of this study was to evaluate the robustness of the innovator product and five generic formulations to crystallization following storage at stress conditions. Products were purchased from a pharmacy and stored at 40°C/75% relative humidity (RH), open dish conditions. Crystallinity was determined using X-ray diffraction. The quantity of the ingredients in the formulations were determined using different approaches and the various factors that might cause instability in the formulations were studied. After 4 weeks of open dish storage at 40°C/75% RH, one of the generic formulations showed evidence of tacrolimus crystallization. Further investigations revealed batch-to-batch variations in crystallization tendency with the extent of crystallinity varying between 50 and 100% for different batches. Crystallization was also observed at lower storage temperatures (30°C) when the RH was maintained at 75%. It was found that crystallization could be induced in a model formulation by wet granulating an ethanolic solution of the drug with lactose and drying at 60-70°C followed by exposure to stress conditions. It seems probable that the generic that was susceptible to crystallization contains amorphous drug physically mixed with polymeric excipients, rather than as an amorphous solid dispersion. This study highlights the importance of considering the manufacturing process on the stability of the resultant amorphous product.

  1. Multiple conformational states in retrospective virtual screening - homology models vs. crystal structures: beta-2 adrenergic receptor case study.

    Science.gov (United States)

    Mordalski, Stefan; Witek, Jagna; Smusz, Sabina; Rataj, Krzysztof; Bojarski, Andrzej J

    2015-01-01

    Distinguishing active from inactive compounds is one of the crucial problems of molecular docking, especially in the context of virtual screening experiments. The randomization of poses and the natural flexibility of the protein make this discrimination even harder. Some of the recent approaches to post-docking analysis use an ensemble of receptor models to mimic this naturally occurring conformational diversity. However, the optimal number of receptor conformations is yet to be determined. In this study, we compare the results of a retrospective screening of beta-2 adrenergic receptor ligands performed on both the ensemble of receptor conformations extracted from ten available crystal structures and an equal number of homology models. Additional analysis was also performed for homology models with up to 20 receptor conformations considered. The docking results were encoded into the Structural Interaction Fingerprints and were automatically analyzed by support vector machine. The use of homology models in such virtual screening application was proved to be superior in comparison to crystal structures. Additionally, increasing the number of receptor conformational states led to enhanced effectiveness of active vs. inactive compounds discrimination. For virtual screening purposes, the use of homology models was found to be most beneficial, even in the presence of crystallographic data regarding the conformational space of the receptor. The results also showed that increasing the number of receptors considered improves the effectiveness of identifying active compounds by machine learning methods. Graphical abstractComparison of machine learning results obtained for various number of beta-2 AR homology models and crystal structures.

  2. A linear relationship between crystal size and fragment binding time observed crystallographically: implications for fragment library screening using acoustic droplet ejection.

    Directory of Open Access Journals (Sweden)

    Krystal Cole

    Full Text Available High throughput screening technologies such as acoustic droplet ejection (ADE greatly increase the rate at which X-ray diffraction data can be acquired from crystals. One promising high throughput screening application of ADE is to rapidly combine protein crystals with fragment libraries. In this approach, each fragment soaks into a protein crystal either directly on data collection media or on a moving conveyor belt which then delivers the crystals to the X-ray beam. By simultaneously handling multiple crystals combined with fragment specimens, these techniques relax the automounter duty-cycle bottleneck that currently prevents optimal exploitation of third generation synchrotrons. Two factors limit the speed and scope of projects that are suitable for fragment screening using techniques such as ADE. Firstly, in applications where the high throughput screening apparatus is located inside the X-ray station (such as the conveyor belt system described above, the speed of data acquisition is limited by the time required for each fragment to soak into its protein crystal. Secondly, in applications where crystals are combined with fragments directly on data acquisition media (including both of the ADE methods described above, the maximum time that fragments have to soak into crystals is limited by evaporative dehydration of the protein crystals during the fragment soak. Here we demonstrate that both of these problems can be minimized by using small crystals, because the soak time required for a fragment hit to attain high occupancy depends approximately linearly on crystal size.

  3. A linear relationship between crystal size and fragment binding time observed crystallographically: implications for fragment library screening using acoustic droplet ejection.

    Science.gov (United States)

    Cole, Krystal; Roessler, Christian G; Mulé, Elizabeth A; Benson-Xu, Emma J; Mullen, Jeffrey D; Le, Benjamin A; Tieman, Alanna M; Birone, Claire; Brown, Maria; Hernandez, Jesus; Neff, Sherry; Williams, Daniel; Allaire, Marc; Orville, Allen M; Sweet, Robert M; Soares, Alexei S

    2014-01-01

    High throughput screening technologies such as acoustic droplet ejection (ADE) greatly increase the rate at which X-ray diffraction data can be acquired from crystals. One promising high throughput screening application of ADE is to rapidly combine protein crystals with fragment libraries. In this approach, each fragment soaks into a protein crystal either directly on data collection media or on a moving conveyor belt which then delivers the crystals to the X-ray beam. By simultaneously handling multiple crystals combined with fragment specimens, these techniques relax the automounter duty-cycle bottleneck that currently prevents optimal exploitation of third generation synchrotrons. Two factors limit the speed and scope of projects that are suitable for fragment screening using techniques such as ADE. Firstly, in applications where the high throughput screening apparatus is located inside the X-ray station (such as the conveyor belt system described above), the speed of data acquisition is limited by the time required for each fragment to soak into its protein crystal. Secondly, in applications where crystals are combined with fragments directly on data acquisition media (including both of the ADE methods described above), the maximum time that fragments have to soak into crystals is limited by evaporative dehydration of the protein crystals during the fragment soak. Here we demonstrate that both of these problems can be minimized by using small crystals, because the soak time required for a fragment hit to attain high occupancy depends approximately linearly on crystal size.

  4. Merging drops in a Teflon tube, and transferring fluid between them, illustrated by protein crystallization and drug screening.

    Science.gov (United States)

    Feuerborn, A; Prastowo, A; Cook, P R; Walsh, E

    2015-01-01

    The ability to manipulate drops with small volumes has many practical applications. Current microfluidic devices generally exploit channel geometry and/or active external equipment to control drops. Here we use a Teflon tube attached to a syringe pump and exploit the properties of interfaces between three immiscible liquids to create particular fluidic architectures. We then go on to merge any number of drops (with volumes of micro- to nano-liters) at predefined points in time and space in the tube; for example, 51 drops were merged in a defined order to yield one large drop. Using a different architecture, specified amounts of fluid were transferred between 2 nl drops at specified rates; for example, 2.5 pl aliquots were transferred (at rates of ~500 fl s(-1)) between two drops through inter-connecting nano-channels (width ~40 nm). One proof-of-principle experiment involved screening conditions required to crystallize a protein (using a concentration gradient created using such nano-channels). Another demonstrated biocompatibility; drugs were mixed with human cells grown in suspension or on surfaces, and the treated cells responded like those grown conventionally. Although most experiments were performed manually, moderate high-throughput potential was demonstrated by mixing ~1000 different pairs of 50 nl drops in ~15 min using a robot. We suggest this reusable, low-cost, and versatile methodology could facilitate the introduction of microfluidics into workflows of many experimental laboratories.

  5. Screening of lettuce germplasm for agronomic traits under low water conditions

    Science.gov (United States)

    After a preliminary screening of over 3,500 varieties, we selected 200 cultivars of butterhead, cos, crisphead, leaf, and stem lettuce (Lactuca sativa L.) and wild prickly lettuce (Lactuca serriola L.) to test under high water (150% ET) and low water (50% ET) conditions in the field, and tracked com...

  6. Are All Latinas the Same?: Perceived Breast Cancer Screening Barriers and Facilitative Conditions

    Science.gov (United States)

    Buki, Lydia P.; Borrayo, Evelinn A.; Feigal, Benjamin M.; Carrillo, Iris Y.

    2004-01-01

    In this article, we examine perceived breast cancer screening barriers and facilitative conditions for immigrant women from Mexico, Puerto Rico, Cuba, El Salvador, and South America (N=58). Focus groups conducted separately with women of each ancestry were analyzed using grounded theory methods. Identified barriers comprise secrecy, lack of…

  7. Are All Latinas the Same?: Perceived Breast Cancer Screening Barriers and Facilitative Conditions

    Science.gov (United States)

    Buki, Lydia P.; Borrayo, Evelinn A.; Feigal, Benjamin M.; Carrillo, Iris Y.

    2004-01-01

    In this article, we examine perceived breast cancer screening barriers and facilitative conditions for immigrant women from Mexico, Puerto Rico, Cuba, El Salvador, and South America (N=58). Focus groups conducted separately with women of each ancestry were analyzed using grounded theory methods. Identified barriers comprise secrecy, lack of…

  8. Optical anisotropy of cubic photonic crystals under conditions of multiple-mode light propagation

    Science.gov (United States)

    Ukleev, T. A.; Yurasova, D. I.; Shevchenko, N. N.; Sel'kin, A. V.

    2016-11-01

    Bragg reflection spectra of light are studied for opal-like photonic crystals made of polystyrene spheres. A resonant enhancement of reflectivity is observed in cross-polarization configuration of the analyzer and polarizer when varying the azimuthal orientation of a sample in respect to the incidence plane. The cross-polarization effect takes place at oblique incidence of light on the lateral (111) crystal plane with the plane of incidence being non-perpendicular to the inclined (11-1) crystal plane. The effect is shown to be due to the multiple Bragg diffraction of light when the resonant Bragg conditions are fulfilled at a certain angle of incidence and azimuth for the lateral and inclined crystal planes simultaneously.

  9. Committee report: Method for evaluating conditions nominated for population-based screening of newborns and children.

    Science.gov (United States)

    Calonge, Ned; Green, Nancy S; Rinaldo, Piero; Lloyd-Puryear, Michele; Dougherty, Denise; Boyle, Coleen; Watson, Michael; Trotter, Tracy; Terry, Sharon F; Howell, R Rodney

    2010-03-01

    The Secretary's Advisory Committee on Heritable Disorders in Newborns and Children is charged with evaluating conditions nominated for addition to the uniform screening panel and consequently making recommendations to the secretary of the US Department of Health and Human Services. This report describes the framework by which the committee approaches its task. Key decision nodes include initial review of every nomination to determine whether conditions are amenable for systematic evidence review, review of systematic evidence reviews conducted by the committee's external review group, and deliberation and formal recommendation for addition or exclusion to the uniform panel. Data analyzed include the accuracy and specificity of screening and diagnostic tests for nominated disorders, the extent of predicted health benefits, harms impact on disease course, and cost from early diagnosis and treatment. The committee process is guided by approaches used by similar entities, but more flexible criteria are sometimes needed to accommodate data limitations stemming from the rarity of many of these conditions. Possible outcomes of committee review range from recommendation to add a nominated condition to the uniform panel; provide feedback on specific gaps in evidence that must be addressed before making a decision; or rejection of a nomination (e.g., because of identified harms). The committee's structured evidence-based assessment of nominated conditions supports a consistently rigorous, iterative and transparent approach to its making recommendations regarding broad population-based screening programs for rare conditions in infants and children.

  10. Cervical and breast cancer screening participation for women with chronic conditions in France: results from a national health survey.

    Science.gov (United States)

    Constantinou, Panayotis; Dray-Spira, Rosemary; Menvielle, Gwenn

    2016-03-31

    Comorbidity at the time of diagnosis is an independent prognostic factor for survival among women suffering from cervical or breast cancer. Although cancer screening practices have proven their efficacy for mortality reduction, little is known about adherence to screening recommendations for women suffering from chronic conditions. We investigated the association between eleven chronic conditions and adherence to cervical and breast cancer screening recommendations in France. Using data from a cross-sectional national health survey conducted in 2008, we analyzed screening participation taking into account self-reported: inflammatory systemic disease, cancer, cardiovascular disease, chronic respiratory disease, depression, diabetes, dyslipidemia, hypertension, obesity, osteoarthritis and thyroid disorders. We first computed age-standardized screening rates among women who reported each condition. We then estimated the effect of having reported each condition on adherence to screening recommendations in logistic regression models, with adjustment for sociodemographic characteristics, socioeconomic position, health behaviours, healthcare access and healthcare use. Finally, we investigated the association between chronic conditions and opportunistic versus organized breast cancer screening using multinomial logistic regression. The analyses were conducted among 4226 women for cervical cancer screening and 2056 women for breast cancer screening. Most conditions studied were not associated with screening participation. Adherence to cervical cancer screening recommendations was higher for cancer survivors (OR = 1.73 [0.98-3.05]) and lower for obese women (OR = 0.73 [0.57-0.93]), when accounting for our complete range of screening determinants. Women reporting chronic respiratory disease or diabetes participated less in cervical cancer screening, except when adjusting for socioeconomic characteristics. Adherence to breast cancer screening recommendations was lower for

  11. A quality comparison of protein crystals grown under containerless conditions generated by diamagnetic levitation, silicone oil and agarose gel.

    Science.gov (United States)

    Cao, Hui-Ling; Sun, Li-Hua; Li, Jian; Tang, Lin; Lu, Hui-Meng; Guo, Yun-Zhu; He, Jin; Liu, Yong-Ming; Xie, Xu-Zhuo; Shen, He-Fang; Zhang, Chen-Yan; Guo, Wei-Hong; Huang, Lin-Jun; Shang, Peng; He, Jian-Hua; Yin, Da-Chuan

    2013-10-01

    High-quality crystals are key to obtaining accurate three-dimensional structures of proteins using X-ray diffraction techniques. However, obtaining such protein crystals is often a challenge. Several containerless crystallization techniques have been reported to have the ability to improve crystal quality, but it is unknown which is the most favourable way to grow high-quality protein crystals. In this paper, a quality comparison of protein crystals which were grown under three containerless conditions provided by diamagnetic levitation, silicone oil and agarose gel was conducted. A control experiment on a vessel wall was also simultaneously carried out. Seven different proteins were crystallized under the four conditions, and the crystal quality was assessed in terms of the resolution limit, the mosaicity and the Rmerge. It was found that the crystals grown under the three containerless conditions demonstrated better morphology than those of the control. X-ray diffraction data indicated that the quality of the crystals grown under the three containerless conditions was better than that of the control. Of the three containerless crystallization techniques, the diamagnetic levitation technique exhibited the best performance in enhancing crystal quality. This paper is to our knowledge the first report of improvement of crystal quality using a diamagnetic levitation technique. Crystals obtained from agarose gel demonstrated the second best improvement in crystal quality. The study indicated that the diamagnetic levitation technique is indeed a favourable method for growing high-quality protein crystals, and its utilization is thus potentially useful in practical efforts to obtain well diffracting protein crystals.

  12. Investigation of the operating conditions to morphology evolution of β-L-glutamic acid during seeded cooling crystallization

    Science.gov (United States)

    Zhang, Fangkun; Liu, Tao; Huo, Yan; Guan, Runduo; Wang, Xue Z.

    2017-07-01

    In this paper the effects of operating conditions including cooling rate, initial supersaturation, and seeding temperature were investigated on the morphology evolution of β-L-glutamic acid (β-LGA) during seeded cooling crystallization. Based on the results of in-situ image acquisition of the crystal morphology evolution during the crystallization process, it was found that the crystal products tend to be plate-like or short rod-like under a slow cooling rate, low initial supersaturation, and low seeding temperature. In the opposite, the operating conditions of a faster cooling rate, higher initial supersaturation, and higher seeding temperature tend to produce long rod-like or needle-like crystals, and meanwhile, the length and width of crystal products will be increased together with a wider crystal size distribution (CSD). The aspect ratio of crystals, defined by the crystal length over width measured from in-situ or sample images, was taken as a shape index to analyze the crystal morphologies. Based on comparative analysis of the experimental results, guidelines on these operating conditions were given for obtaining the desired crystal shapes, along with the strategies for obtaining a narrower CSD for better product quality. Experimental verifications were performed to illustrate the proposed guidelines on the operating conditions for seeded cooling crystallization of LGA solution.

  13. Nucleation and growth of crystals under cirrus and polar stratospheric cloud conditions

    Science.gov (United States)

    Hallett, John; Queen, Brian; Teets, Edward; Fahey, James

    1995-03-01

    Laboratory studies examine phase changes of hygroscopic substances which occur as aerosol in stratosphere and troposphere (sodium chloride, ammonium sulfate, ammonium bisulfate, nitric acid, sulfuric acid), under controlled conditions, in samples volume 1 to 10(exp -4) ml. Crystallization of salts from supersaturated solutions is examined by slowly evaporating a solution drop on a substrate, under controlled relative humidity, until self nucleation occurs; controlled nucleation of ice in a mm capillary U-tube gives a measured ice crystallization velocity at known supercooling. Two states of crystallization occur for regions where hydrates exist. It is inferred that all of the materials readily exist as supersaturated/supercooled solutions; the degree of metastability appears to be slightly enhanced by inclusion of aircraft produced soot. The crystallization velocity is taken as a measure of viscosity. Results suggest an approach to a glass transition at high molality, supersaturation and/or supercooling within the range of atmospheric interest. It is hypothesized that surface reactions occur more readily on solidified particles - either crystalline or glass, whereas volume reactions are more important on droplets with sufficiently low viscosity and volume diffusivity. Implications are examined for optical properties of such particles in the atmosphere. In a separate experiment, crystal growth was examined in a modified thermal vapor diffusion chamber over the range of cirrus temperature (-30 to -70 C) and under controlled supersaturation and air pressure. The crystals grew at a velocity of 1-2 microns/s, thickness 60-70 micron, in the form of thin column crystals. Design criteria are given for a system to investigate particle growth down to -100 C, (PSC temperatures) where nitric acid particles can be grown under similar control and in the form of hydrate crystals.

  14. Cervical and breast cancer screening participation for women with chronic conditions in France: results from a national health survey

    OpenAIRE

    Constantinou, Panayotis; Dray-Spira, Rosemary; Menvielle, Gwenn

    2016-01-01

    Background Comorbidity at the time of diagnosis is an independent prognostic factor for survival among women suffering from cervical or breast cancer. Although cancer screening practices have proven their efficacy for mortality reduction, little is known about adherence to screening recommendations for women suffering from chronic conditions. We investigated the association between eleven chronic conditions and adherence to cervical and breast cancer screening recommendations in France. Metho...

  15. Crystallization of the Membrane-Associated Annexin B1: Roles of Additive Screen, Dynamic Light Scattering, and Bioactivity Assay

    Energy Technology Data Exchange (ETDEWEB)

    Ding, F.; Xu, Y; Azzi, A; Zhu, D; Rehse, D; Chen, C; Sun, S; Lin, S

    2010-01-01

    Annexin B1 (AnxB1) is a calcium-dependent phospholipid binding protein from Taenia solium cysticercus and has been reported to possess anticoagulant activity, to inhibit phospholipase A{sub 2}, and to regulate membrane transport. Native AnxB1 and its selenomethionyl derivative have been overproduced in Escherichia coli and purified. The results of dynamic light scattering analysis showed that Hepes buffer combined with low concentration salts (NaCl or CaCl{sub 2}) was beneficial for preventing aggregation and for AnxB1 stabilization in the storage. After the additive screen, crystals have been yielded in the presence of guanidine hydrochloride (Gn-HCl). We determined that a low concentration of Gn-HCl significantly delayed clotting time and increased anticoagulant activity. Analysis of the crystal showed that in the presence of Gn-HCl, AnxB1 crystallizes in orthorhombic space group, which is modified from the cubic space group for crystals grown in the absence of Gn-HCl. A high quality data set (at 1.9 {angstrom}) has been collected successfully for crystals of L-selenomethionine labeled protein in the presence of Gn-HCl, to solve the structure with the single anomalous dispersion method (SAD). The unit cell parameters are a = 102.35 {angstrom}, b = 103.59 {angstrom}, c = 114.60 {angstrom}, {alpha} = {beta} = {gamma} = 90.00{sup o}.

  16. Reevaluation of the plant "gemstones": Calcium oxalate crystals sustain photosynthesis under drought conditions.

    Science.gov (United States)

    Tooulakou, Georgia; Giannopoulos, Andreas; Nikolopoulos, Dimosthenis; Bresta, Panagiota; Dotsika, Elissavet; Orkoula, Malvina G; Kontoyannis, Christos G; Fasseas, Costas; Liakopoulos, Georgios; Klapa, Maria I; Karabourniotis, George

    2016-09-01

    Land plants face the perpetual dilemma of using atmospheric carbon dioxide for photosynthesis and losing water vapors, or saving water and reducing photosynthesis and thus growth. The reason behind this dilemma is that this simultaneous exchange of gases is accomplished through the same minute pores on leaf surfaces, called stomata. In a recent study we provided evidence that pigweed, an aggressive weed, attenuates this problem exploiting large crystals of calcium oxalate as dynamic carbon pools. This plant is able to photosynthesize even under drought conditions, when stomata are closed and water losses are limited, using carbon dioxide from crystal decomposition instead from the atmosphere. Abscisic acid, an alarm signal that causes stomatal closure seems to be implicated in this function and for this reason we named this path "alarm photosynthesis." The so-far "enigmatic," but highly conserved and widespread among plant species calcium oxalate crystals seem to play a crucial role in the survival of plants.

  17. In vivo screening of extracellular matrix components produced under multiple experimental conditions implanted in one animal.

    Science.gov (United States)

    Higuera, Gustavo A; Hendriks, Jeanine A A; van Dalum, Joost; Wu, Ling; Schotel, Roka; Moreira-Teixeira, Liliana; van den Doel, Mirella; Leijten, Jeroen C H; Riesle, Jens; Karperien, Marcel; van Blitterswijk, Clemens A; Moroni, Lorenzo

    2013-06-01

    Animal experiments help to progress and ensure safety of an increasing number of novel therapies, drug development and chemicals. Unfortunately, these also lead to major ethical concerns, costs and limited experimental capacity. We foresee a coercion of all these issues by implantation of well systems directly into vertebrate animals. Here, we used rapid prototyping to create wells with biomaterials to create a three-dimensional (3D) well-system that can be used in vitro and in vivo. First, the well sizes and numbers were adjusted for 3D cell culture and in vitro screening of molecules. Then, the functionality of the wells was evaluated in vivo under 36 conditions for tissue regeneration involving human mesenchymal stem cells (hMSCs) and bovine primary chondrocytes (bPCs) screened in one animal. Each biocompatible well was controlled to contain μl-size volumes of tissue, which led to tissue penetration from the host and tissue formation under implanted conditions. We quantified both physically and biologically the amounts of extracellular matrix (ECM) components found in each well. Using this new concept the co-culture of hMSCs and bPCs was identified as a positive hit for cartilage tissue repair, which was a comparable result using conventional methods. The in vivo screening of candidate conditions opens an entirely new range of experimental possibilities, which significantly abates experimental animal use and increases the pace of discovery of medical treatments.

  18. Elevated serum CA 19-9 at screening tests: underlying conditions and role of abdominopelvic CT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Yang [University of Louisville, Department of Radiology and Molecular Imaging Research Center, Louisville, KY (United States); Seoul National University Hospital, Department of Radiology, Healthcare System Gangnam Center, Seoul (Korea, Republic of); Kim, Se Hyung [Seoul National University Hospital, Department of Radiology and the Institute of Radiation Medicine, Seoul (Korea, Republic of); Kim, Soo Young [Seoul National University Hospital, Department of Radiology, Healthcare System Gangnam Center, Seoul (Korea, Republic of); Bundang CHA Hospital, Department of Radiology, Bundang (Korea, Republic of)

    2014-10-15

    To investigate underlying conditions of patients with elevated CA 19-9 at screening tests and to evaluate diagnostic performance of abdominopelvic CT. One hundred and thirteen patients with elevated CA 19-9 (>37 U/ml) who underwent abdominopelvic CT in a screening program were selected. Underlying conditions were determined by reviewing all available data and follow-up records. Patients were categorized into malignancy, benign, and normal/non-related disease groups. Their mean CA 19-9 and percent of patients with CA 19-9 ≥ 100 U/ml were compared. Diagnostic sensitivity of CT for detecting underlying conditions of elevated CA 19-9 was analysed. Seventeen patients (17/113, 15 %) had 17 elevated CA 19-9-related malignancies, and 55 patients (55/113, 48.7 %) had 70 benign diseases. Mean CA 19-9 and percent of patients with CA 19-9 ≥ 100 U/ml in the malignancy group were significantly higher than in the two other groups. CT detected all except one malignant lesion with a detection sensitivity of 94.1 % (16/17). Of 70 CA 19-9-related benign diseases, CT detected 34 benign diseases (48.6 %) providing an alternative diagnosis for elevated CA 19-9. Abdominopelvic CT is not only useful in detecting malignancies, but can also diagnose alternative benign causes of elevated CA 19-9 in asymptomatic screening tests. (orig.)

  19. Polyoxometalate/Polyethylene Glycol Interactions in Water: From Nanoassemblies in Water to Crystal Formation by Electrostatic Screening.

    Science.gov (United States)

    Buchecker, Thomas; Le Goff, Xavier; Naskar, Bappaditya; Pfitzner, Arno; Diat, Olivier; Bauduin, Pierre

    2017-06-22

    In the last decade organic-inorganic hybrid materials have become essential in materials science as they combine properties of both building blocks. Nowadays the main routes for their synthesis involve electrostatic coupling, covalent grafting, and/or solvent effects. In this field, polyoxometalates (POMs) have emerged as interesting inorganic functional building blocks due to their outstanding properties. In the present work the well-known α-Keggin polyoxometalate, α-PW12 O40(3-) (PW), is shown to form hybrid crystalline materials with industrial (neutral) polyethylene glycol oligomers (PEG) under mild conditions, that is, in aqueous medium and at room temperature. The formation of these materials originates from the spontaneous self-assembly of PW with EOx , (EO=ethylene oxide) with at least four EO units (x>4). The PW-PEG nanoassemblies, made of a POM surrounded by about two PEG oligomers, are stabilized by electrostatic repulsions between the negatively charged PW anions. Addition of NaCl, aimed at screening the inter-nanoassembly repulsions, induces aggregation and formation of hybrid crystalline materials. Single-crystal analysis showed a high selectivity of PW towards EO5 -EO6 oligomers from PEG200, which is made of a mixture of EO3-8 . Therefore, a general "soft" route to produce POM-organic composites is proposed here through the control of electrostatic repulsions between spontaneously formed nanoassemblies in water. However, this rational design of new POM hybrid (crystalline) materials with hydrophilic blocks, using such a simple mixing procedure of the components, requires a deep understanding of the molecular interactions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Effect of Processing Conditions on the Crystallization behavior and Destabilization Kinetics of Oil-in-Water Emulsions

    OpenAIRE

    Martini, Silvana; Tippetts, Megan

    2008-01-01

    The objective of this research was to systematically study the effect of processing conditions on the crystallization behavior and destabilization mechanisms of oil-in-water emulsions. The effect of crystallization temperature (T c) and homogenization conditions on both thermal behavior and destabilization mechanisms were analyzed. Results show that the crystallization of lipids present in the emulsions was inhibited when compared with bulk lipids as evidenced by a lower onset and peak temper...

  1. Effects of microscopic boundary conditions on plastic deformations of small-sized single crystals

    DEFF Research Database (Denmark)

    Kuroda, Mitsutoshi; Tvergaard, Viggo

    2009-01-01

    The finite deformation version of the higher-order gradient crystal plasticity model proposed by the authors is applied to solve plane strain boundary value problems, in order to obtain an understanding of the effect of the higher-order boundary conditions. Numerical solutions are carried out...... effect of higher-order boundary conditions on the overall deformation mode of the block is observed. The bent foil has free surfaces through which dislocations can go out of the material, and we observe a strong size-dependent mechanical response resulting from the surface condition assumed....

  2. A Versatile System for High-Throughput In Situ X-ray Screening and Data Collection of Soluble and Membrane-Protein Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Broecker, Jana; Klingel, Viviane; Ou, Wei-Lin; Balo, Aidin R.; Kissick, David J.; Ogata, Craig M.; Kuo, Anling; Ernst, Oliver P.

    2016-10-12

    In recent years, in situ data collection has been a major focus of progress in protein crystallography. Here, we introduce the Mylar in situ method using Mylar-based sandwich plates that are inexpensive, easy to make and handle, and show significantly less background scattering than other setups. A variety of cognate holders for patches of Mylar in situ sandwich films corresponding to one or more wells makes the method robust and versatile, allows for storage and shipping of entire wells, and enables automated crystal imaging, screening, and goniometerbased X-ray diffraction data-collection at room temperature and under cryogenic conditions for soluble and membrane-protein crystals grown in or transferred to these plates. We validated the Mylar in situ method using crystals of the water-soluble proteins hen egg-white lysozyme and sperm whale myoglobin as well as the 7-transmembrane protein bacteriorhodopsin from Haloquadratum walsbyi. In conjunction with current developments at synchrotrons, this approach promises high-resolution structural studies of membrane proteins to become faster and more routine.

  3. Automated nutrient screening system enables high-throughput optimisation of microalgae production conditions.

    Science.gov (United States)

    Radzun, Khairul Adzfa; Wolf, Juliane; Jakob, Gisela; Zhang, Eugene; Stephens, Evan; Ross, Ian; Hankamer, Ben

    2015-01-01

    Microalgae provide an excellent platform for the production of high-value-products and are increasingly being recognised as a promising production system for biomass, animal feeds and renewable fuels. Here, we describe an automated screen, to enable high-throughput optimisation of 12 nutrients for microalgae production. Its miniaturised 1,728 multiwell format allows multiple microalgae strains to be simultaneously screened using a two-step process. Step 1 optimises the primary elements nitrogen and phosphorous. Step 2 uses Box-Behnken analysis to define the highest growth rates within the large multidimensional space tested (Ca, Mg, Fe, Mn, Zn, Cu, B, Se, V, Si) at three levels (-1, 0, 1). The highest specific growth rates and maximum OD750 values provide a measure for continuous and batch culture. The screen identified the main nutrient effects on growth, pairwise nutrient interactions (for example, Ca-Mg) and the best production conditions of the sampled statistical space providing the basis for a targeted full factorial screen to assist with optimisation of algae production.

  4. Effect of ultrasonic irradiation on the number of acetylsalicylic acid crystals produced under the supersaturated condition and the ability of controlling the final crystal size via primary nucleation

    Science.gov (United States)

    Miyasaka, Etsuko; Kato, Yumi; Hagisawa, Minoru; Hirasawa, Izumi

    2006-03-01

    The purposes of this study were to investigate the effects of ultrasound irradiation on the number of crystals formed in an acetylsalicyclic acid crystallization process and to assess the controllability of the final product size via the number of primary nuclei. The number of crystals present after primary nucleation was counted and the relationship between the final product size and the number of crystals was examined. Additionally, the growing ASA crystals were observed, since ultrasound energy not only may control primary nucleation but may also the perfection of the crystal shape. At a high level of ultrasonic energy, ultrasound irradiation increased the average number of crystals, an effect that has been reported often; however, at a low level of ultrasonic energy it decreased the average number of crystals, and moreover, these opposing ultrasonic effects on the number of crystals interchanged at a specific energy threshold. These results reveal two novel phenomena—that there is an energy region where ultrasonic irradiation inhibits primary nucleation, and that a specific amount of ultrasonic energy is needed to activate primary nucleation. On the other hand, the final product size almost depended upon the number of primary nuclei, indicating that the final product size could be controlled via the number of crystals influenced by ultrasound irradiation. According to the photographs of crystals, they were not destroyed by the process. Therefore, it was proposed that ultrasound energy does not destroy the perfection of the crystal shape but only controls primary nucleation under the condition: both short irradiation time and low supersaturated condition.

  5. The influence of crystallization conditions on the morphology of lactose intended for use as a carrier for dry powder aerosols.

    Science.gov (United States)

    Zeng, X M; Martin, G P; Marriott, C; Pritchard, J

    2000-06-01

    Lactose has been widely used as a carrier for inhalation aerosols. The carrier morphology is believed to affect the delivery of the drug. The aim of this study was to investigate the effects of crystallization conditions on the morphology of alpha-lactose monohydrate intended for use as the carrier for dry powder aerosols. The crystallization of lactose was carried out from aqueous solutions at different supersaturations, temperatures, different stages of crystallization and in the presence of different water-miscible organic solvents. The majority of lactose crystals were found to be either tomahawk-shaped or pyramidal after crystallization at an initial lactose concentration between 33-43% w/w, but these became prismatic if the lactose concentration was increased to 50% w/w. A further increase in the lactose concentration to 60% w/w led to the preparation of elongated cuboidal crystals. Higher initial lactose concentrations tended to result in the crystallization of more elongated particles. Crystallization at 40 degrees C was shown to prepare lactose crystals with a more regular shape and a smoother surface than those crystallized at 0 degrees C. Lactose particles generated during the later stage of crystallization were found to be more regular in shape with a smoother surface than those prepared in the earlier stage. The addition of 10% (v/v) methanol or ethanol or acetone to the mother liquor increased the growth rate of lactose particles whereas addition of propanol or glycerine inhibited the rate of crystal growth. Lactose crystals prepared in the presence of glycerine were more regularly shaped with a smoother surface than those prepared in the presence of ethanol or acetone. All the resultant crystals were shown to comprise alpha-lactose monohydrate. Lactose crystals could be prepared with a precisely defined morphology by means of carefully controlling the crystallization conditions.

  6. Resonant tunneling effect in one-dimensional twinned lattice photonic crystal under total reflection conditions

    Science.gov (United States)

    Feng, Xi; Li, Hu; Yuxia, Tang

    2016-07-01

    Under total reflection conditions, it typically seems as though light waves will be reflected completely on the interface; in actuality, the waves can penetrate the medium as evanescent waves. In this paper, we present a twinned lattice photonic crystal with a unit cell composed of AB layers and their mirror. We assume that the refractive index n 0 of the input and output end is equal to n B and larger than n A . We first demonstrate the dependence of band structure on the incidence angle and normalized wavelength, in which the resonant tunneling bands are exposed. We then draw a comparison of bands between ABBA and AB. To conclude, we discuss the resonant tunneling effect in the twinned lattice photonic crystal under the total reflection conditions. As incidence angle increases, the resonant tunneling band ultimately vanishes completely.

  7. Saturable Nonlinearity in Photovoltaic-Photorefractive Crystals Under Open-circuit Condition

    Institute of Scientific and Technical Information of China (English)

    GUO Ru; LING Zhen-Fang; CHEN Xiao-Hu; ZHANG Guo-Quan; ZHANG Xin-Zheng; WEN Hai-Dong; JIANG Ying; LIU Si-Min

    2000-01-01

    We show that the refractive index change induced by a focused incident beam with an additional incoherent uniform illumination in photovoltaic-photorefractive crystals under open-circuit condition has a saturable nonlinearity form. The incoherent uniform background illumination can be used to increase the effective dark irradiance. The formation time of the photovoltaic soliton can be decreased by keeping the intensity of the soliton at a higher value without over-saturation by use of the background illumination.

  8. The Experimental Investigation Of The Screen Operation In The Parametric Resonance Conditions

    Directory of Open Access Journals (Sweden)

    Bąk Łukasz

    2015-12-01

    Full Text Available In this paper the experimental studies of the screen working in the parametric resonance condition are discussed. The investigations are conducted for laboratory parametric resonance screen. The measuring test is performed for four cases of tension force values. The full sheet metal instead of the sieve is used. For each considered case the natural frequency of the plate and the parameter modulation frequency are determined. The achieved results are presented and discussed. It is shown that the highest sieve plate amplitude is obtained when the parameter modulation frequency is two times larger than natural frequency of the sieve plate. This parametric resonance vibration was observed only for tension force equal to 4000 N because of the rotational speed limits of electrical vibratos.

  9. Indian patients' attitudes towards chairside screening in a dental setting for medical conditions.

    Science.gov (United States)

    Sansare, Kaustubh; Raghav, Mamta; Kasbe, Abhiram; Karjodkar, Freny; Sharma, Neeraj; Gupta, Ambika; Singh, Harneet; Iyengar, Asha; Patil, Seema; Selvamuthukumar, Sanarpalayam C; Krithika, Chandrasekaran; Glick, Michael; Greenberg, Barbara L

    2015-10-01

    India has a high prevalence of cardiovascular disease (CVD), diabetes mellitus (DM), tuberculosis (TB), human immunodeficiency virus/acquired immune-deficiency syndrome (HIV/AIDS) and hepatitis B. United States-based studies indicate provider and patient support for medical screening in the dental setting. We assessed patient attitudes towards, and willingness to participate in, medical screening in the dental setting in India. A 5-point Likert scale survey (with scores ranging from 1=very important/willing to 5=very unimportant/unwilling) was given to a convenience sample of adult patients visiting five university-based dental clinics (clinic group) and one private-practice setting (private group). The Mann-Whitney U-test was used to compare mean response scores between patient groups. Logistic regression was used to assess factors associated with a favourable outcome. Both patient groups felt it important for dentists to identify increased risk for medical conditions (89.3% vs. 94.9%, respectively; P=0.02). The majority of patients were willing to have a dentist screen for the specified conditions: CVD (80.6% clinic and 84.5% private); DM (84.5% clinic and 77.5% private); TB (76.7% clinic and 73.2% private); hepatitis (73.3% clinic and 67.5% private); and HIV/AIDS (71.0% clinic and 70.5% private). The majority of patients were willing to participate in chairside screening that yielded immediate results (84.6% clinic and 86.1% private), discuss results immediately (85.8% clinic and 87.2% private) and pay 150 Indian rupees (55.9% clinic and 91.7% private). Younger patients (dental settings [adjusted odds ratio (OR)=0.63; 95% confidence interval (95% CI): 0.26-0.84] and be available for screening that yielded immediate results (adjusted OR=0.63; 95% CI: 0.40-0.99). Indian dental patients were in favour of chairside medical screening. © 2015 FDI World Dental Federation.

  10. Crystal Growth of Hen Egg-White Lysozyme (HEWL) under Various Gravity Conditions

    Science.gov (United States)

    Pan, Weichun; Xu, Jin; Tsukamoto, Katsuo; Koizumi, Masako; Yamazaki, Tomoya; Zhou, Ru; Li, Ang; Fu, Yuying

    2013-08-01

    Motivated by the enhancement of protein quality under microgravity condition, the behaviors of crystal growth under various gravity conditions have been monitored via Foton Satellite and parabolic flight. We found that the normal growth rate and the step velocity would be enhanced only at high protein concentration. Although the difference of diffusion between monomer lysozyme molecule and main impurity species in HWEL dimer may be able to explain this enhancement in long period at high protein concentration, it is not valid at low lysozyme concentration and it can't explain the results obtained by parabolic flight, in which microgravity condition maintained only about 20 s. In order to compromise this contradiction, cluster, universal existing in protein solution, has been picked up. The dynamic light scattering technique figured out dimer is served as the seed for cluster formation. Due to its large size, cluster keeps still under microgravity. Via this mechanism, the purification of lysozyme above crystal surface has been achieved. We also found the two supergravity (˜1.5 g) periods immediately before and after microgravity period have different effects on the step velocity. The pre-MG period depresses the step velocity while the post-MG enhances it. This odd phenomenon ascribes to two factors: (1) the flow rate modification and (2) the purity of protein solution immediate above crystal surface.

  11. Liquid crystal displays for aircraft engineering

    Directory of Open Access Journals (Sweden)

    Kovalenko L. F.

    2009-06-01

    Full Text Available Operating conditions for liquid-crystal displays of aircraft instruments have been examined. Requirements to engineering of a liquid-crystal display for operation in severe environment have been formulated. The implementation options for liquid-crystal matrix illumination have been analyzed in order to ensure the sufficient brightness depending on external illumination of a display screen.

  12. Ibuprofen-Amino Acids Co-Crystal Screening Via Co-Grinding Methods

    Directory of Open Access Journals (Sweden)

    Othman Muhamad Fitri

    2016-01-01

    Full Text Available The importance of pharmaceutical co-crystals now has been recognized in order to improve the research and development in pharmaceutical industries. Low solubility of active pharmaceutical ingredient (API has led to the growth of new pharmaceutical co-crystals formation as it enhances the physicochemical properties of the API. In this works, preparation of new co-crystal formation between ibuprofen (IBP with selected amino acid compounds were performed by using dry grinding and liquid assisted grinding (LAG techniques. Ibuprofen (IBP was selected as the API meanwhile glycine (GLY, L-alanine (ALA and L-proline (PRO were selected as co-crystal former (CCF agents. The products of IBP-co-former from grinding experiments for the formation of co-crystals were characterized and verified using X-Ray Powder Diffraction (XRPD, Differential Scanning Calorimetry (DSC and Fourier Transform Infra-Red Spectroscopy (FTIR. The finding reveals that the IBP-PRO co-crystals have successfully formed. For IBP-PRO system, new crystalline peaks from XRPD were recorded at 2θ values of 4.374°, 5.436° and 10.944° from dry grinding technique and 4.41°, 5.436° and 10.962° for liquid assisted grinding (LAG technique. A new melting point of 257.49 °C was discovered for IBP-ALA indicates the possibility of co-crystals formation. On the other hand, the analysis for IBP-GLY shows that no co-crystals formed in the system.

  13. High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals

    OpenAIRE

    Tony Varghese; Courtney Hollar; Joseph Richardson; Nicholas Kempf; Chao Han; Pasindu Gamarachchi; David Estrada; Mehta, Rutvik J.; Yanliang Zhang

    2016-01-01

    Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride base...

  14. Serious games for screening pre-dementia conditions: from virtuality to reality? A pilot project.

    Science.gov (United States)

    Zucchella, Chiara; Sinforiani, Elena; Tassorelli, Cristina; Cavallini, Elena; Tost-Pardell, Daniela; Grau, Sergi; Pazzi, Stefania; Puricelli, Stefano; Bernini, Sara; Bottiroli, Sara; Vecchi, Tomaso; Sandrini, Giorgio; Nappi, Giuseppe

    2014-01-01

    Conventional cognitive assessment is based on a pencil-and-paper neuropsychological evaluation, which is time consuming, expensive and requires the involvement of several professionals. Information and communication technology could be exploited to allow the development of tools that are easy to use, reduce the amount of data processing, and provide controllable test conditions. Serious games (SGs) have the potential to be new and effective tools in the management and treatment of cognitive impairments Serious games for screening pre-dementia conditions: from virtuality to reality? A pilot project in the elderly. Moreover, by adopting SGs in 3D virtual reality settings, cognitive functions might be evaluated using tasks that simulate daily activities, increasing the "ecological validity" of the assessment. In this commentary we report our experience in the creation of the Smart Aging platform, a 3D SGand virtual environment-based platform for the early identification and characterization of mild cognitive impairment.

  15. Metabolite profiling of microfluidic cell culture conditions for droplet based screening

    DEFF Research Database (Denmark)

    2015-01-01

    We investigate the impact of droplet culture conditions on cell metabolic state by determining key metabolite concentrations in S. cerevisiae cultures in different microfluidic droplet culture formats. Control of culture conditions is critical for single cell/clone screening in droplets....... Metabolite profiling provides a more nuanced estimate of cell state compared to proliferation studies alone. We show that the choice of droplet incubation format impacts cell proliferation and metabolite production. The standard syringe incubation of droplets exhibited metabolite profiles similar to oxygen...... limited cultures, whereas the metabolite profiles of cells cultured in the alternative wide tube droplet incubation format resemble those from aerobic culture. Furthermore, we demonstrate retained droplet stability and size in the new better oxygenated droplet incubation format....

  16. Screening a strain of Aspergillus niger and optimization of fermentation conditions for degradation of aflatoxin B₁.

    Science.gov (United States)

    Zhang, Wei; Xue, Beibei; Li, Mengmeng; Mu, Yang; Chen, Zhihui; Li, Jianping; Shan, Anshan

    2014-11-13

    Aflatoxin B₁, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B₁ after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B₁ after 48 h of fermentation in nutrient broth (NB). Optimization of fermentation conditions for aflatoxin B₁ degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B₁ was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B₁ degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B₁ degradation by the supernatant were examined. Results indicated that aflatoxin B₁ degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment.

  17. Stress and mixed boundary conditions for two-dimensional dodecagonal quasi-crystal plates

    Indian Academy of Sciences (India)

    Yan Gao; Si-Peng Xu; Bao-Sheng Zhao

    2007-05-01

    For plate bending and stretching problems in two-dimensional (2D) dodecagonal quasi-crystal (QC) media, the reciprocal theorem and the general solution for QCs are applied in a novel way to obtain the appropriate stress and mixed boundary conditions accurate to all order. The method developed by Gregory and Wan is used to generate necessary conditions which the prescribed data on the edge of the plate must satisfy in order that it should generate a decaying state within the plate; these decaying state conditions are obtained explicitly for axisymmetric bending and stretching of a circular plate when stress or mixed conditions are imposed on the plate edge. They are then used for the correct formulation of boundary conditions for the interior solution. For the stress data, our boundary conditions coincide with those obtained in conventional forms of plate theories. More importantly, appropriate boundary conditions with a set of mixed edge-data are obtained for the first time. Furthermore, the corresponding necessary conditions for transversely isotropic elastic plate are obtained directly, and their isotropic elastic counterparts are also obtained.

  18. Patients' ratings of genetic conditions validate a taxonomy to simplify decisions about preconception carrier screening via genome sequencing.

    Science.gov (United States)

    Leo, Michael C; McMullen, Carmit; Wilfond, Benjamin S; Lynch, Frances L; Reiss, Jacob A; Gilmore, Marian J; Himes, Patricia; Kauffman, Tia L; Davis, James V; Jarvik, Gail P; Berg, Jonathan S; Harding, Cary; Kennedy, Kathleen A; Simpson, Dana Kostiner; Quigley, Denise I; Richards, C Sue; Rope, Alan F; Goddard, Katrina A B

    2016-03-01

    Advances in genome sequencing and gene discovery have created opportunities to efficiently assess more genetic conditions than ever before. Given the large number of conditions that can be screened, the implementation of expanded carrier screening using genome sequencing will require practical methods of simplifying decisions about the conditions for which patients want to be screened. One method to simplify decision making is to generate a taxonomy based on expert judgment. However, expert perceptions of condition attributes used to classify these conditions may differ from those used by patients. To understand whether expert and patient perceptions differ, we asked women who had received preconception genetic carrier screening in the last 3 years to fill out a survey to rate the attributes (predictability, controllability, visibility, and severity) of several autosomal recessive or X-linked genetic conditions. These conditions were classified into one of five taxonomy categories developed by subject experts (significantly shortened lifespan, serious medical problems, mild medical problems, unpredictable medical outcomes, and adult-onset conditions). A total of 193 women provided 739 usable ratings across 20 conditions. The mean ratings and correlations demonstrated that participants made distinctions across both attributes and categories. Aggregated mean attribute ratings across categories demonstrated logical consistency between the key features of each attribute and category, although participants perceived little difference between the mild and serious categories. This study provides empirical evidence for the validity of our proposed taxonomy, which will simplify patient decisions for results they would like to receive from preconception carrier screening via genome sequencing.

  19. Screening of tetrachlorodibenzo- p-dioxin-degrading fungi capable of producing extracellular peroxidases under various conditions.

    Science.gov (United States)

    Manji, S; Ishihara, A

    2004-01-01

    Forty-six pulp-bleaching fungi were screened for production of key enzymes for conversion of polychlorinated dibenzo-p-dioxins--lignin peroxidase (LiP), manganese peroxidase (MnP), and manganese-independent peroxidase (MiP)--under various conditions that would allow their utilization in the environment. Of 38 MnP-producing strains with MiP activity, 22 produced LiP. Three of the new isolates, Bjerkandera sp. strains MS191, MS325, and MS1167, were the best producers of the three different peroxidases, and had reasonable growth rates. The most promising Bjerkandera sp. strain, MS325, exhibited significant levels of LiP and MnP activities under various conditions, e.g., nutrient nitrogen-sufficient or -limited conditions, conditions with or without Mn(II), and changes in temperature (15-37 degrees C). Furthermore, the ability of this strain to degrade 1,3,6,8-tetrachlorodibenzo- p-dioxin was confirmed. The results presented here indicate that utilization of Bjerkandera sp. strain MS325 on a practical scale in the environment has several advantages over many white rot fungi, which produce extracellular peroxidases only under specific conditions such as nutrient limitation.

  20. Generalized nematohydrodynamic boundary conditions with application to bistable twisted nematic liquid-crystal displays

    KAUST Repository

    Fang, Angbo

    2008-12-08

    Parallel to the highly successful Ericksen-Leslie hydrodynamic theory for the bulk behavior of nematic liquid crystals (NLCs), we derive a set of coupled hydrodynamic boundary conditions to describe the NLC dynamics near NLC-solid interfaces. In our boundary conditions, translational flux (flow slippage) and rotational flux (surface director relaxation) are coupled according to the Onsager variational principle of least energy dissipation. The application of our boundary conditions to the truly bistable π -twist NLC cell reveals a complete picture of the dynamic switching processes. It is found that the thus far overlooked translation-rotation dissipative coupling at solid surfaces can accelerate surface director relaxation and enhance the flow rate. This can be utilized to improve the performance of electro-optical nematic devices by lowering the required switching voltages and reducing the switching times. © 2008 The American Physical Society.

  1. DARPin-Based Crystallization Chaperones Exploit Molecular Geometry as a Screening Dimension in Protein Crystallography.

    Science.gov (United States)

    Batyuk, Alexander; Wu, Yufan; Honegger, Annemarie; Heberling, Matthew M; Plückthun, Andreas

    2016-04-24

    DARPin libraries, based on a Designed Ankyrin Repeat Protein consensus framework, are a rich source of binding partners for a wide variety of proteins. Their modular structure, stability, ease of in vitro selection and high production yields make DARPins an ideal starting point for further engineering. The X-ray structures of around 30 different DARPin complexes demonstrate their ability to facilitate crystallization of their target proteins by restricting flexibility and preventing undesired interactions of the target molecule. However, their small size (18 kDa), very hydrophilic surface and repetitive structure can limit the DARPins' ability to provide essential crystal contacts and their usefulness as a search model for addressing the crystallographic phase problem in molecular replacement. To optimize DARPins for their application as crystallization chaperones, rigid domain-domain fusions of the DARPins to larger proteins, proven to yield high-resolution crystal structures, were generated. These fusions were designed in such a way that they affect only one of the terminal capping repeats of the DARPin and do not interfere with residues involved in target binding, allowing to exchange at will the binding specificities of the DARPin in the fusion construct. As a proof of principle, we designed rigid fusions of a stabilized version of Escherichia coli TEM-1 β-lactamase to the C-terminal capping repeat of various DARPins in six different relative domain orientations. Five crystal structures representing four different fusion constructs, alone or in complex with the cognate target, show the predicted relative domain orientations and prove the validity of the concept.

  2. Screening of bacterial strains producing maltotetraose-forming amylase and the conditions for enzyme production.

    Science.gov (United States)

    Yan, Z; She, X; Li, M; Zhang, S

    1992-01-01

    The authors isolated 1380 bacterial strains from 290 soil samples collected in China and 490 strains were received from other research teams in this institute. By screening 707 strains showed starch-hydrolyzing activity. By further screening and paper chromatographic test, three strains with maltotetraose as the major product were obtained. The maltotetraose was further confirmed by treatment with beta-amylase splitting to maltose and with glucoamylase to glucose. The most promising strain was 537.1, which produced maltotetraose about 90% (w/w) in the starch hydrolysate. While the other two strains produced maltose and maltotriose besides maltotetraose. Strain 537.1 was tentatively identified as Alcaligenes sp. The optimum conditions for enzyme production were as follows: medium composition: 1.5% maltose; 0.5% peptone with initial pH of 7.0-7.5; cultured at 27-28 degrees C for 48 hours on rotary shaker. The culture supernatant of the strain 537.1 can hydrolyze starch and different kinds of cereal flour with a high yield of maltotetraose in the hydrolysate.

  3. Evaluation of the effects of 3D diffusion, crystal geometry, and initial conditions on retrieved time-scales from Fe-Mg zoning in natural oriented orthopyroxene crystals

    Science.gov (United States)

    Krimer, Daniel; Costa, Fidel

    2017-01-01

    Volcano petrologists and geochemists increasingly use time-scale determinations of magmatic processes from modeling the chemical zoning patterns in crystals. Most determinations are done using one-dimensional traverses across a two-dimensional crystal section. However, crystals are three-dimensional objects with complex shapes, and diffusion and re-equilibration occurs in multiple dimensions. Given that we can mainly study the crystals in two-dimensional petrographic thin sections, the determined time-scales could be in error if multiple dimensional and geometrical effects are not identified and accounted for. Here we report the results of a numerical study where we investigate the role of multiple dimensions, geometry, and initial conditions of Fe-Mg diffusion in an orthopyroxene crystal with the view towards proper determinations of time scales from modeling natural crystals. We found that merging diffusion fronts (i.e. diffusion from multiple directions) causes 'additional' diffusion that has the greatest influence close to the crystal's corners (i.e. where two crystal faces meet), and with longer times the affected area widens. We also found that the one-dimensional traverses that can lead to the most accurate calculated time-scales from natural crystals are along the b- crystallographic axis on the ab-plane when model inputs (concentration and zoning geometry) are taken as measured (rather than inferred from other observations). More specifically, accurate time-scales are obtained if the compositional traverses are highly symmetrical and contain a concentration plateau measured through the crystal center. On the other hand, for two-dimensional models the ab- and ac-planes are better suited if the initial (pre-diffusion) concentration and zoning geometry inputs are known or can be estimated, although these are a priory unknown, and thus, may be difficult to use in practical terms. We also found that under certain conditions, a combined one-dimensional and two

  4. High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals

    Science.gov (United States)

    Varghese, Tony; Hollar, Courtney; Richardson, Joseph; Kempf, Nicholas; Han, Chao; Gamarachchi, Pasindu; Estrada, David; Mehta, Rutvik J.; Zhang, Yanliang

    2016-09-01

    Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm2 with 60 °C temperature difference between the hot side and cold side. The highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications.

  5. High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals

    Science.gov (United States)

    Varghese, Tony; Hollar, Courtney; Richardson, Joseph; Kempf, Nicholas; Han, Chao; Gamarachchi, Pasindu; Estrada, David; Mehta, Rutvik J.; Zhang, Yanliang

    2016-01-01

    Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm2 with 60 °C temperature difference between the hot side and cold side. The highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications. PMID:27615036

  6. High-performance and flexible thermoelectric films by screen printing solution-processed nanoplate crystals.

    Science.gov (United States)

    Varghese, Tony; Hollar, Courtney; Richardson, Joseph; Kempf, Nicholas; Han, Chao; Gamarachchi, Pasindu; Estrada, David; Mehta, Rutvik J; Zhang, Yanliang

    2016-09-12

    Screen printing allows for direct conversion of thermoelectric nanocrystals into flexible energy harvesters and coolers. However, obtaining flexible thermoelectric materials with high figure of merit ZT through printing is an exacting challenge due to the difficulties to synthesize high-performance thermoelectric inks and the poor density and electrical conductivity of the printed films. Here, we demonstrate high-performance flexible films and devices by screen printing bismuth telluride based nanocrystal inks synthesized using a microwave-stimulated wet-chemical method. Thermoelectric films of several tens of microns thickness were screen printed onto a flexible polyimide substrate followed by cold compaction and sintering. The n-type films demonstrate a peak ZT of 0.43 along with superior flexibility, which is among the highest reported ZT values in flexible thermoelectric materials. A flexible thermoelectric device fabricated using the printed films produces a high power density of 4.1 mW/cm(2) with 60 °C temperature difference between the hot side and cold side. The highly scalable and low cost process to fabricate flexible thermoelectric materials and devices demonstrated here opens up many opportunities to transform thermoelectric energy harvesting and cooling applications.

  7. Public support for neonatal screening for Pompe disease, a broad-phenotype condition

    NARCIS (Netherlands)

    S.S. Weinreich (Stephanie ); T. Rigter (Tessel); C.G. El (Carla); W.J. Dondorp (Wybo Jan); P.J. Kostense (Piet); A.T. van der Ploeg (Ans); A.J.J. Reuser (Arnold); M.C. Cornel (Martina); M.L.C. Hagemans (Marloes)

    2012-01-01

    textabstractBackground: Neonatal screening for Pompe disease has been introduced in Taiwan and a few U.S. states, while other jurisdictions including some European countries are piloting or considering this screening. First-tier screening flags both classic infantile and late-onset Pompe disease,

  8. Holographic Screening Soliton in Biased Two-photon Photorefractive Crystal%双光子光折变晶体中全息屏蔽空间孤子

    Institute of Scientific and Technical Information of China (English)

    姚纪欢; 吉选芒; 姜其畅; 刘劲松

    2012-01-01

    为了得到双光子光折变晶体中全息屏蔽空间孤子的结果,基于双光束耦合耗散系统和双光子光折变效应,证明了外加偏压的双光子光折变晶体中存在一种新的全息屏蔽空间孤子.此类孤子需要满足两种平衡,一是损耗与增益之间的平衡,增益由抽运光通过两波耦合为信号光提供;二是衍射与非线性之间的平衡,非线性包括外加电场的非均匀屏蔽和两波耦合对折射率的周期性调制.在信号光远小于抽运光的条件下得出了全息亮和暗孤子的解析表达式.研究了全息屏蔽孤子的演化特性.%A new two-photon holographic screening soliton in biased photorefractive materials is demonstrated based on the two-wave coupling dissipative systems and two-photon photorefractive effect to study the holographic screening soliton in a biased two-photon photorefractive crystals. Two types of balances need to be reached. Loss is balanced by gain provided by the pump beam via two-wave mixing, and diffraction is balanced by nonlinearity that is due to the spatially nonuniform screening of the applied field and the periodic modulation of the refractive in-Sex via two-wave mixing. The bright and dark analytical solutions are obtained under the condition that the signal beam is much weaker than the pump beam. Dynamical evolutions of holographic two-photon screening soliton are numerically simulated under stable condition.

  9. [Effect of the crystallization conditions of tetracycline base on the properties of the powders and drug forms obtained. The dependence of the degree of dispersion of tetracycline base on the crystallization conditions].

    Science.gov (United States)

    Lin'kov, G I; Zhukovskaia, S A; Dzhabarov, D N; Nabokov, V S

    1977-09-01

    Characteristics of the powder dispersity of tetracycline base samples prepared by directed crystallization with variation of the process conditions were determined by the sedimentation method. It was found that the speed of the solution agitation had the maximum effect on the level and nature of the dispersity. The rate of the solution temperature and pH changing during the crystallization process had also a significant effect at low agitation speed.

  10. Crystal structure of importin-{alpha} complexed with a classic nuclear localization sequence obtained by oriented peptide library screening

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, A.A.S.; Fontes, M.R.M. [UNESP, Universidade Estadual Paulista, Botucatu, SP (Brazil); Yang, S.N.Y. [University of Melbourne, Melbourne (Australia); Harris, J.M. [Queensland University of Technology, Brisbane (Australia); Jans, D.A. [Monash University, Clayton (Australia); Kobe, B. [University of Queensland, Brisbane, QU (Australia)

    2012-07-01

    Full text: Importin-{alpha} (Imp{alpha}) plays a role in the classical nuclear import pathway, binding to cargo proteins with activities in the nucleus. Different Imp{alpha} paralogs responsible for specific cargos can be found in a single organism. The cargos contain nuclear localization sequences (NLSs), which are characterized by one or two clusters of basic amino acids (monopartite and bipartite NLSs, respectively). In this work we present the crystal structure of Imp{alpha} from M. musculus (residues 70-529, lacking the auto inhibitory domain) bound to a NLS peptide (pepTM). The peptide corresponds to the optimal sequence obtained by an oriented peptide library experiment designed to probe the specificity of the major NLS binding site. The peptide library used five degenerate positions and identified the sequence KKKRR as the optimal sequence for binding to this site for mouse Imp{alpha} (70-529). The protein was obtained using an E. coli expression system and purified by affinity chromatography followed by an ion exchange chromatography. A single crystal of Imp{alpha} -pepTM complex was grown by the hanging drop method. The data were collected using the Synchrotron Radiation Source LNLS, Brazil and processed to 2.3. Molecular replacement techniques were used to determine the crystal structure. Electron density corresponding to the peptide was present in both major and minor binding sites The peptide is bound to Imp{alpha} similar as the simian virus 40 (SV40) large tumour (T)-antigen NLS. Binding assays confirmed that the peptide bound to Imp{alpha} with low nM affinities. This is the first time that structural information has been linked to an oriented peptide library screening approach for importin-{alpha}; the results will contribute to understanding of the sequence determinants of classical NLSs, and may help identify as yet unidentified classical NLSs in novel proteins. (author)

  11. Algorithm-driven high-throughput screening of colloidal nanoparticles under simulated physiological and therapeutic conditions.

    Science.gov (United States)

    Bhirde, Ashwinkumar A; Sindiri, Sivasish; Calco, Gina N; Aronova, Maria A; Beaucage, Serge L

    2017-02-09

    Colloidal nanoparticles have shown tremendous potential as cancer drug carriers and as phototherapeutics. However, the stability of nanoparticles under physiological and phototherapeutic conditions is a daunting issue, which needs to be addressed in order to ensure a successful clinical translation. The design, development and implementation of unique algorithms are described herein for high-throughput hydrodynamic size measurements of colloidal nanoparticles. The data obtained from such measurements provide clinically-relevant particle size distribution assessments that are directly related to the stability and aggregation profiles of the nanoparticles under putative physiological and phototherapeutic conditions; those profiles are not only dependent on the size and surface coating of the nanoparticles, but also on their composition. Uncoated nanoparticles showed varying degrees of association with bovine serum albumin, whereas PEGylated nanoparticles did not exhibit significant association with the protein. The algorithm-driven, high-throughput size screening method described in this report provides highly meaningful size measurement patterns stemming from the association of colloidal particles with bovine serum albumin used as a protein model. Noteworthy is that this algorithm-based high-throughput method can accomplish sophisticated hydrodynamic size measurement protocols within days instead of years it would take conventional hydrodynamic size measurement techniques to achieve a similar task.

  12. Under Pressure: New Geobarometer Developed to Determine Crystallization Conditions and Storage Depths of Intermediate Magmas

    Science.gov (United States)

    Harmon, L.; Gualda, G. A. R.; Ghiorso, M. S.; Cowlyn, J.

    2015-12-01

    A new phase equilibria geobarometer successfully determines pressures of magma storage in plagioclase+orthopyroxene+clinopyroxene (POC) bearing intermediate magmas. The geobarometer utilizes rhyolite-MELTS to determine crystallization conditions utilizing the glass compositions coexisting with the POC assemblage in natural samples. POC stability is strongly affected by water content and oxygen fugacity (fO2). We tested fO2 values ranging from +1 to +4 delta-QFM, which spans the fO2 range of intermediate magmas. Water content was tested from water-saturated to 4 wt% below saturation. The geobarometer was applied to two intermediate POC-bearing systems - Mount Ruapehu in the southern Taupo Volcanic Zone, New Zealand, and the Palmas unit of the Serra Geral Formation in the Paraná Volcanics, Brazil. Both systems were tested from 25 MPa to 400 MPa and from 700 ºC to 1200 ºC. Ruapehu is an active, structurally well-understood volcano in the Taupo Volcanic Zone; it serves as a methodological testing ground for the geobarometer. POC-bearing pumice clasts show a bimodal distribution of crystallization pressures for different eruptions, with modes of ~90 MPa and 130 MPa, consistent with field interpretations of different eruptive styles based on juvenile clast textures and previous knowledge of the magma plumbing system. The bimodal distribution indicates that the magma batches were tapped at different pressures (and depths). Ruapehu magmas are water saturated and have fO2 of delta-QFM equal to ~+1. The model substantiates these conditions, as rhyolite-MELTS calculations with lower water contents and different fO2 values do not produce the observed POC mineral assemblage. Preliminary results from the Paraná Volcanics suggest juvenile, fiamme-like blob structures equilibrated at ~50 MPa, were water saturated, and had an fO2 between delta-QFM +1 and +1.5. The geobarometer has potential to unravel crystallization conditions of shallow, glass-bearing andesites to dacites.

  13. Optimizing calculation of phase screen distribution with minimum condition along an inhomogeneous turbulent path

    Science.gov (United States)

    Shao, Wen-Yi; Xian, Hao

    2016-11-01

    When building an experimental platform for light propagation along an inhomogeneous turbulent path, it is very essential to set up the reasonable distribution of phase screen. Based on multi-layered model of phase screen, an iterative optimization algorithm of phase screen position is given in this paper. Thereafter, the optimal position of phase screens is calculated under the Hufnagel-Valley5/7 and Hefei-day turbulence profile. The results show that the positions of phase screen calculated by the iterative algorithm can fit well with the turbulence profile rather than mechanically placed phase screens at equal distance. Compared with the uniform distribution of phase screens position, the residual phase error of the iterative algorithm decreases very significantly. The similarity degree between them is minimal when number of layers is equal to two. Project supported by the National Natural Science Foundation of China (Grant No. 61308082).

  14. Screening for pre-malignant conditions in the oral cavity of chronic tobacco chewers

    Directory of Open Access Journals (Sweden)

    Priyanka Mahawar, Shweta Anand, Umesh Sinha, Madhav Bansal, Sanjay Dixit

    2011-01-01

    Full Text Available Oral cancer is a major health problem in tobacco users all over the world. It is one of the ten most common cancers in the world. Oral cancer is almost always preceded by some type of precancerous lesion. The precancerous lesions can be detected upto 15years, prior to their change to an invasive carcinoma. It usually affects between the ages of 15 and 40 years. It may be triggered by factors like frequency and duration of tobacco consumption, alcohol, poor oral hygiene etc. This study was conducted primarily to screen chronic tobacco chewers for the presence of oral pre-malignant conditions and secondly to educate them about the hazards of tobacco and motivate them to quit the habit. This was a cross sectional study conducted at Badi gawaltoli area of Indore. Tobacco chewers using tobacco for more than 5yrs were included in the study. Chronic tobacco chewers were screened for oral pre-malignant lesions followed by an educational intervention about the harmful effects of tobacco. Two follow ups were made to motivate them to quit the habit and to get treatment for their lesions. An open ended semi-structured questionnaire was administered to chronic tobacco chewers to assess their habit of tobacco chewing, smoking, their knowledge regarding lesions in their mouth, hazards of tobacco and any cessation efforts. Among the 80 identified chronic tobacco chewers, 60 were males and 20 were females. Lesions such as leukoplakia, erythroplakia and oral sub-mucosal fibrosis were found in 10 females (50% and 24 males (40%.

  15. Minor Elements in Nakhlite Pyroxenes: Does Cr Record Changes in REDOX Conditions during Crystallization?

    Science.gov (United States)

    McKay, G.; Schwandt, C.; Le, L.; Mikouchi, T.

    2007-01-01

    Nakhlites are olivine-bearing clinopyroxene cumulates. Based on petrographic characteristics, they may be divided into groups that cooled at different rates and may have been formed at different depths in a single flow. The order of cooling rate from slowest to fastest is NWA998crystallization history of the nakhlite magma. Moreover, because the composition of the nakhlite parent melt cannot be directly determined, inversion of the major and minor element composition of the cumulate pyroxene cores can be used to estimate the composition of that melt. Moreover, minor and trace element zoning of pyroxenes can provide information about the oxidation conditions under which these samples crystallized. Thus it is important to understand the major and minor element zoning in the cumulus pyroxenes. While major elements are nearly homogeneous, minor elements exhibit distinctive zoning patterns that vary from one nakhlite to another. This abstract reports unusual Cr zoning patterns in pyroxenes from MIL03346 (MIL) and contrast these with pyroxenes from Y593 and Nakhla.

  16. Experimental study on crystallization kinetics of alkali feldspar under high T-P conditions

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the granite-NaF-H2O system, there exists a nucleation lag in the course of alkali feldspar crystallization indicated by experiments on crystallization kinetics. The nucleation lag time is about 18 h at 700℃ and about 6 h at 650℃. Meanwhile, both nucleation rate and crystal-growth rate of alkali feldspar are not constant during the crystallization process, but vary with crystal- lization time. Here we suggest that the lag time should be taken into account in the calculation formula of nucleation rate and crystal-growth rate to obtain more reliable parameters.

  17. Influence of colloidal particle transfer on the quality of self-assembling colloidal photonic crystal under confined condition

    Institute of Scientific and Technical Information of China (English)

    赵永强; 李娟; 刘秋艳; 董文钧; 陈本永; 李超荣

    2015-01-01

    The relationship between colloidal particle transfer and quality of colloidal photonic crystal (CPC) is investigated by comparing colloidal particle self-assembling under the vertical channel (VC) and horizontal channel (HC) conditions. Both the theoretical analyses and the experimental measurements indicate that crystal quality depends on the stability of mass transfer. For the VC, colloidal particle transfer takes place in a stable laminar flow, which is conducive to forming high-quality crystal. In contrast, it happens in an unstable turbulent flow for the HC. Crystals with cracks and uneven surface formed under the HC condition can be seen from the images of field emission scanning electron microscope (SEM) and three-dimensional (3D) laser scanning microscope (LSM), respectively.

  18. A drunken search in crystallization space.

    Science.gov (United States)

    Fazio, Vincent J; Peat, Thomas S; Newman, Janet

    2014-10-01

    The REMARK280 field of the Protein Data Bank is the richest open source of successful crystallization information. The REMARK280 field is optional and currently uncurated, so significant effort needs to be applied to extract reliable data. There are well over 15 000 crystallization conditions available commercially from 12 different vendors. After putting the PDB crystallization information and the commercial cocktail data into a consistent format, these data are used to extract information about the overlap between the two sets of crystallization conditions. An estimation is made as to which commercially available conditions are most appropriate for producing well diffracting crystals by looking at which commercial conditions are found unchanged (or almost unchanged) in the PDB. Further analyses include which commercial kits are the most appropriate for shotgun or more traditional approaches to crystallization screening. This analysis suggests that almost 40% of the crystallization conditions found currently in the PDB are identical or very similar to a commercial condition.

  19. Conditions of crystallization of the Ural platinum-bearing ultrabasic massifs: evidence from melt inclusions

    Science.gov (United States)

    Simonov, Vladimir; Puchkov, Victor; Prikhod'ko, Vladimir; Stupakov, Sergey; Kotlyarov, Alexey

    2013-04-01

    Conditions of the Ural platinum-bearing ultramafic massifs formation attract attention of numerous researchers. A most important peculiarity of such plutons is their dunite cores, to which commercial Pt deposits are related. There are a different opinions about genesis of these massifs and usual methods not always can solve this question. As a result of melt inclusions study in the Cr-spinel the new data on physical and chemical parameters of dunite crystallization of the Nizhnii Tagil platinum-bearing ulrabasic massif (Ural) was obtained. The comparative analysis of Cr-spinels, containing melt inclusions, has shown essential differences of these minerals from chromites of the ultrabasic ophiolite complexes and of modern oceanic crust. Contents of major chemical components in the heated and quenched melt inclusions are close to those in the picrite and this testifies dunite crystallization from ultrabasic (to 24 wt.% MgO) magma. On the variation diagrams for inclusions in Cr-spinel the following changes of chemical compositions are established: during SiO2 growth there is falling of FeO, MgO, and increase of CaO, Na2O contents. Values of TiO2, Al2O3, K2O and P2O5 remain as a whole constant. Comparing to the data on the melt inclusions in Cr-spinel from the Konder massif, we see that values of the most part of chemical components (SiO2, TiO2, K2O, P2O5) are actually overlapped. At the same time, for the Nizhnii Tagil platinum-bearing massif the big maintenances of FeO and CaO in inclusions are marked. Distinct dependence of the majority of components from the MgO content in inclusions is observed: values TiO2, Al2O3 FeO, CaO and Na2O fall at transition to more magnesia melts. On the peculiarities of distribution of petrochemical characteristics melt inclusions in considered Cr-spinels are co-ordinated with the data on evolution of compositions of melts and rocks of model stratified ultramafic plutons during their crystallization in the magmatic chambers. On the

  20. Solvability condition for needle crystals at large undercooling in a nonlocal model of solidification

    Science.gov (United States)

    Caroli, B.; Caroli, C.; Roulet, B.; Langer, J. S.

    1986-01-01

    It is explicitly shown that, in a realistic model of diffusion-controlled dendritic solidification, Ivantsov's continuous family of steady-state needle crystals is destroyed by the addition of surface tension. The starting point is in the exact integro-differential equation for the one-sided model, in two dimensions, in a moving frame of reference. In the limit of large undercooling, where the range of the diffusion field is much smaller than the radius of curvature of the tip of the needle, this problem is reduced to a linear, inhomogeneous differential equation of infinite order. A solvability condition for this equation is derived and it is shown that solutions cease to exist for arbitrarily small but finite isotropic surface tension.

  1. Screening of phenylpyruvic acid producers and optimization of culture conditions in bench scale bioreactors.

    Science.gov (United States)

    Coban, Hasan B; Demirci, Ali; Patterson, Paul H; Elias, Ryan J

    2014-11-01

    Alpha keto acids are deaminated forms of amino acids that have received significant attention as feed and food additives in the agriculture and medical industries. To date, their production has been commonly performed at shake-flask scale with low product concentrations. In this study, production of phenylpyruvic acid (PPA), which is the alpha keto acid of phenylalanine was investigated. First, various microorganisms were screened to select the most efficient producer. Thereafter, growth parameters (temperature, pH, and aeration) were optimized in bench scale bioreactors to maximize both PPA and biomass concentration in bench scale bioreactors, using response surface methodology. Among the four different microorganisms evaluated, Proteus vulgaris was the most productive strain for PPA production. Optimum temperature, pH, and aeration conditions were determined as 34.5 °C, 5.12, and 0.5 vvm for PPA production, whereas 36.9 °C, pH 6.87, and 0.96 vvm for the biomass production. Under these optimum conditions, PPA concentration was enhanced to 1,054 mg/L, which was almost three times higher than shake-flask fermentation concentrations. Moreover, P. vulgaris biomass was produced at 3.25 g/L under optimum conditions. Overall, this study demonstrated that optimization of growth parameters improved PPA production in 1-L working volume bench-scale bioreactors compared to previous studies in the literature and was a first step to scale up the production to industrial production.

  2. Protein crystallization under microgravity conditions. Analysis of the results of Russian experiments performed on the International Space Station in 2005-2015

    Science.gov (United States)

    Boyko, K. M.; Timofeev, V. I.; Samygina, V. R.; Kuranova, I. P.; Popov, V. O.; Koval'chuk, M. V.

    2016-09-01

    Conditions of mass transport to growing crystals have a considerable effect on the crystal size and quality. The reduction of convective transport can help improve the quality of crystals for X-ray crystallography. One approach to minimizing convective transport is crystallization in a microgravity environment, in particular, in space. The data obtained by our research team in protein crystallization experiments on the International Space Station are surveyed and analyzed.

  3. Effect of Solidification Condition on Microstructure and Mechanical Properties of Single Crystal Superalloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    CMSX-2 single crystals with different primary dendrite arm spacing were obtained on directional solidification apparatus with high temperature gradient (250 K/cm). The microstructure and elevated temperature stress rupture properties of these single crystals were examined and analyzed.

  4. Nucleotide occupancy of F1-ATPase catalytic sites under crystallization conditions.

    Science.gov (United States)

    Löbau, S; Weber, J; Senior, A E

    1997-03-03

    Using site-directed tryptophan fluorescence we studied nucleotide occupancy of the catalytic sites of Escherichia coli F1-ATPase, under conditions used previously for crystallization and X-ray structure analysis of the bovine mitochondrial enzyme [Abrahams et al. (1994) Nature 370, 621-628]. We found that only two of the three catalytic sites were filled in the E. coli enzyme under these conditions (250 microM MgAMPPNP plus 5 microM MgADP), consistent with what was reported in the bovine F1 X-ray structure. However, subsequent addition of a physiological concentration of MgATP readily filled the third catalytic site. Therefore the enzyme form seen in the X-ray structure results from the fact that it is obtained under sub-saturating nucleotide conditions. The data show that the X-ray structure is compatible with a catalytic mechanism in which all three F1-ATPase catalytic sites must fill with MgATP to initiate steady-state hydrolysis [e.g. Weber and Senior (1996) Biochim. Biophys. Acta 1275, 101-104]. The data further demonstrate that the site-directed tryptophan fluorescence technique can provide valuable support for F1 crystallography studies.

  5. Hitting the target: fragment screening with acoustic in situ co-crystallization of proteins plus fragment libraries on pin-mounted data-collection micromeshes

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xingyu [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Stony Brook University, NY 11794-5215 (United States); Nanjing University, Nanjing, Jiangsu (China); Scalia, Alexander [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Binghamton University, 4400 Vestal Parkway East, NY 13902 (United States); Leroy, Ludmila [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Ministry of Education of Brazil, 70040-020 Brasilia-DF (Brazil); Universidade Federal de Minas Gerais, 6627 Av. Antonio Carlos, 31270-901 Belo Horizonte-MG (Brazil); Cuttitta, Christina M. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); The City University of New York, 2800 Victory Boulevard, Staten Island, NY 10314 (United States); Polizzo, Gina M. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); St Joseph’s College, 155 West Roe Boulevard, East Patchogue, NY 11772 (United States); Ericson, Daniel L. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); University at Buffalo, SUNY, 12 Capen Hall, Buffalo, NY 14260 (United States); Roessler, Christian G. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Campos, Olven [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33414 (United States); Ma, Millie Y. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Comsewogue High School, 565 Bicycle Path, Port Jefferson Station, NY 11776 (United States); Agarwal, Rakhi; Jackimowicz, Rick; Allaire, Marc [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Orville, Allen M. [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); Sweet, Robert M.; Soares, Alexei S., E-mail: soares@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

    2014-05-01

    A method is presented for screening fragment libraries using acoustic droplet ejection to co-crystallize proteins and chemicals directly on micromeshes with as little as 2.5 nl of each component. This method was used to identify previously unreported fragments that bind to lysozyme, thermolysin, and trypsin. Acoustic droplet ejection (ADE) is a powerful technology that supports crystallographic applications such as growing, improving and manipulating protein crystals. A fragment-screening strategy is described that uses ADE to co-crystallize proteins with fragment libraries directly on MiTeGen MicroMeshes. Co-crystallization trials can be prepared rapidly and economically. The high speed of specimen preparation and the low consumption of fragment and protein allow the use of individual rather than pooled fragments. The Echo 550 liquid-handling instrument (Labcyte Inc., Sunnyvale, California, USA) generates droplets with accurate trajectories, which allows multiple co-crystallization experiments to be discretely positioned on a single data-collection micromesh. This accuracy also allows all components to be transferred through small apertures. Consequently, the crystallization tray is in equilibrium with the reservoir before, during and after the transfer of protein, precipitant and fragment to the micromesh on which crystallization will occur. This strict control of the specimen environment means that the crystallography experiments remain identical as the working volumes are decreased from the few microlitres level to the few nanolitres level. Using this system, lysozyme, thermolysin, trypsin and stachydrine demethylase crystals were co-crystallized with a small 33-compound mini-library to search for fragment hits. This technology pushes towards a much faster, more automated and more flexible strategy for structure-based drug discovery using as little as 2.5 nl of each major component.

  6. Analyzing screen heat insulation and its effect on energy consumption while heating building envelopes in conditions of intermittent heating

    Directory of Open Access Journals (Sweden)

    Vytchikov Yuri

    2016-01-01

    Full Text Available The paper is devoted to screen heat insulation and its effect on energy consumption while heating building envelopes in conditions of intermittent heating. It also describes the non-stationary process of heat transfer through heat insulated outer walls. The authors introduce calculation results of specific energy consumption for heating insulated and non-insulted outer walls. The paper proves that energy consumption for heating insulated outer walls depends on the thickness of non-aerated air-space insulation The research shows positive effects of using thermal protection systems with screen thermal insulation in outer building envelopes in conditions of intermitten heating.

  7. Hitting the target: fragment screening with acoustic in situ co-crystallization of proteins plus fragment libraries on pin-mounted data-collection micromeshes.

    Science.gov (United States)

    Yin, Xingyu; Scalia, Alexander; Leroy, Ludmila; Cuttitta, Christina M; Polizzo, Gina M; Ericson, Daniel L; Roessler, Christian G; Campos, Olven; Ma, Millie Y; Agarwal, Rakhi; Jackimowicz, Rick; Allaire, Marc; Orville, Allen M; Sweet, Robert M; Soares, Alexei S

    2014-05-01

    Acoustic droplet ejection (ADE) is a powerful technology that supports crystallographic applications such as growing, improving and manipulating protein crystals. A fragment-screening strategy is described that uses ADE to co-crystallize proteins with fragment libraries directly on MiTeGen MicroMeshes. Co-crystallization trials can be prepared rapidly and economically. The high speed of specimen preparation and the low consumption of fragment and protein allow the use of individual rather than pooled fragments. The Echo 550 liquid-handling instrument (Labcyte Inc., Sunnyvale, California, USA) generates droplets with accurate trajectories, which allows multiple co-crystallization experiments to be discretely positioned on a single data-collection micromesh. This accuracy also allows all components to be transferred through small apertures. Consequently, the crystallization tray is in equilibrium with the reservoir before, during and after the transfer of protein, precipitant and fragment to the micromesh on which crystallization will occur. This strict control of the specimen environment means that the crystallography experiments remain identical as the working volumes are decreased from the few microlitres level to the few nanolitres level. Using this system, lysozyme, thermolysin, trypsin and stachydrine demethylase crystals were co-crystallized with a small 33-compound mini-library to search for fragment hits. This technology pushes towards a much faster, more automated and more flexible strategy for structure-based drug discovery using as little as 2.5 nl of each major component.

  8. Screening and brief intervention for unhealthy substance use in patients with chronic medical conditions: a systematic review.

    Science.gov (United States)

    Timko, Christine; Kong, Calvin; Vittorio, Lisa; Cucciare, Michael A

    2016-11-01

    This systematic review describes studies evaluating screening tools and brief interventions for addressing unhealthy substance use in primary care patients with hypertension, diabetes or depression. Primary care is the main entry point to the health care system for most patients with comorbid unhealthy substance use and chronic medical conditions. Although of great public health importance, systematic reviews of screening tools and brief interventions for unhealthy substance use in this population that are also feasible for use in primary care have not been conducted. Systematic review. We systematically review the research literature on evidence-based tools for screening for unhealthy substance use in primary care patients with depression, diabetes and hypertension, and utilising brief interventions with this population. Despite recommendations to screen for and intervene with unhealthy substance use in primary care patients with chronic medical conditions, the review found little indication of routine use of these practices. Limited evidence suggested the Alcohol Use Disorders Identification Test and Alcohol Use Disorders Identification Test-C screeners had adequate psychometric characteristics in patients with the selected chronic medical conditions. Screening scores indicating more severe alcohol use were associated with health-risk behaviours and poorer health outcomes, adding to the potential usefulness of screening for unhealthy alcohol use in this population. Studies support brief interventions' effectiveness with patients treated for hypertension or depression who hazardously use alcohol or cannabis, for both substance use and chronic medical condition outcomes. Although small, the international evidence base suggests that screening with the Alcohol Use Disorders Identification Test or Alcohol Use Disorders Identification Test-C and brief interventions for primary care patients with chronic medical conditions, delivered by nurses or other providers, are

  9. Mechanical behaviour of vacuum chambers and beam screens under quench conditions in dipole and quadrupole fields

    CERN Document Server

    Rathjen, C

    2002-01-01

    A method based on analytical formulas is described to calculate bending moments, stresses, and deformations of vacuum chambers and beam screens in dipole and in quadrupole fields during a magnet quench. Solutions are given for circular and racetrack shaped structures. Without the need of time consuming calculations the solutions enable a quick design and verification of vacuum chambers and beam screens.

  10. A methodology to determine boundary conditions from forced convection experiments using liquid crystal thermography

    Science.gov (United States)

    Jakkareddy, Pradeep S.; Balaji, C.

    2017-02-01

    This paper reports the results of an experimental study to estimate the heat flux and convective heat transfer coefficient using liquid crystal thermography and Bayesian inference in a heat generating sphere, enclosed in a cubical Teflon block. The geometry considered for the experiments comprises a heater inserted in a hollow hemispherical aluminium ball, resulting in a volumetric heat generation source that is placed at the center of the Teflon block. Calibrated thermochromic liquid crystal sheets are used to capture the temperature distribution at the front face of the Teflon block. The forward model is the three dimensional conduction equation which is solved within the Teflon block to obtain steady state temperatures, using COMSOL. Match up experiments are carried out for various velocities by minimizing the residual between TLC and simulated temperatures for every assumed loss coefficient, to obtain a correlation of average Nusselt number against Reynolds number. This is used for prescribing the boundary condition for the solution to the forward model. A surrogate model obtained by artificial neural network built upon the data from COMSOL simulations is used to drive a Markov Chain Monte Carlo based Metropolis Hastings algorithm to generate the samples. Bayesian inference is adopted to solve the inverse problem for determination of heat flux and heat transfer coefficient from the measured temperature field. Point estimates of the posterior like the mean, maximum a posteriori and standard deviation of the retrieved heat flux and convective heat transfer coefficient are reported. Additionally the effect of number of samples on the performance of the estimation process has been investigated.

  11. A methodology to determine boundary conditions from forced convection experiments using liquid crystal thermography

    Science.gov (United States)

    Jakkareddy, Pradeep S.; Balaji, C.

    2016-05-01

    This paper reports the results of an experimental study to estimate the heat flux and convective heat transfer coefficient using liquid crystal thermography and Bayesian inference in a heat generating sphere, enclosed in a cubical Teflon block. The geometry considered for the experiments comprises a heater inserted in a hollow hemispherical aluminium ball, resulting in a volumetric heat generation source that is placed at the center of the Teflon block. Calibrated thermochromic liquid crystal sheets are used to capture the temperature distribution at the front face of the Teflon block. The forward model is the three dimensional conduction equation which is solved within the Teflon block to obtain steady state temperatures, using COMSOL. Match up experiments are carried out for various velocities by minimizing the residual between TLC and simulated temperatures for every assumed loss coefficient, to obtain a correlation of average Nusselt number against Reynolds number. This is used for prescribing the boundary condition for the solution to the forward model. A surrogate model obtained by artificial neural network built upon the data from COMSOL simulations is used to drive a Markov Chain Monte Carlo based Metropolis Hastings algorithm to generate the samples. Bayesian inference is adopted to solve the inverse problem for determination of heat flux and heat transfer coefficient from the measured temperature field. Point estimates of the posterior like the mean, maximum a posteriori and standard deviation of the retrieved heat flux and convective heat transfer coefficient are reported. Additionally the effect of number of samples on the performance of the estimation process has been investigated.

  12. Crystal growth behavior of LiFePO4 in microwave-assisted hydrothermal condition: from nanoparticle to nanosheet.

    Science.gov (United States)

    Yang, Gang; Ji, Hongmei; Miao, Xiaowei; Hong, Anqing; Yan, Yuan

    2011-06-01

    By using microwave-assisted hydrothermal crystallization approach, LiFePO4 nanoparticles have been synthesized in several minutes without the use of any organic reducing agent and argon protection. The crystal structure and lattice parameters have been analyzed by using the X-ray diffraction patterns (XRD) and Rietveld refined analysis, and the full width at half-maximum (FWHM) of the characteristic peaks. A preferential orientation of crystal growth occurs upon microwave hydrothermal field. The SEM and TEM images show that the LiFePO4 crystals present a change from nanoparticle to nanosheet with the increasing reaction time from 5 to 20 min. All the samples present a couple of redox peaks in their CV profiles. The peak pair corresponds to the charge/discharge reaction of the Fe3+/Fe2+ redox couple, and evidencing the absence of electroactive iron impurities. Because of the LiFePO4 samples prepared without any carbon, the initial charge/discharge capacities and cycleability of absolutely are affected by the crystal structure which is controlled by the microwave irradiation condition. The relation among the microwave reaction condition, crystal morphology, and the electrochemical properties are presented and discussed in the electrochemical test.

  13. Analyses of crystal field and exchange interaction of Dy3Ga5O12 under extreme conditions

    Institute of Scientific and Technical Information of China (English)

    Wang Wei; Qi Xin; Yue Yuan

    2011-01-01

    This paper theoretically investigates the effects of crystal field and exchange interaction field on magnetic properties in dysprosium gallium garnet under extreme conditions (low temperatures and high magnetic fields) based on quantum theory. Here, five sets of crystal field parameters are discussed and compared. It demonstrates that, only considering the crystal field effect, the experiments can not be successfully explained. Thus, referring to the molecular field theory,an effective exchange field associated with the Dy-Dy exchange interaction is further taken into account. Under special consideration of crystal field and the exchange interaction field, it obtains an excellent agreement between the theoretical results and experiments, and further confirms that the exchange interaction field between rare-earth ions has great importance to magnetic properties in paramagnetic rare-earth gallium garnets.

  14. Screening and characterization of Isochrysis strains and optimization of culture conditions for docosahexaenoic acid production.

    Science.gov (United States)

    Liu, Jin; Sommerfeld, Milton; Hu, Qiang

    2013-06-01

    Isochrysis is a genus of marine unicellular microalgae that produces docosahexaenoic acid (DHA, C22:6), a very long chain polyunsaturated fatty acid (PUFA) of significant health and nutritional value. Mass cultivation of Isochrysis for DHA production for human consumption has not been established due to disappointing low DHA productivity obtained from commonly used Isochrysis strains. In this study, 19 natural Isochrysis strains were screened for DHA yields and the results showed that the cellular DHA content ranged from 6.8 to 17.0 % of total fatty acids with the highest DHA content occurring in the exponential growth phase. Isochrysis galbana #153180 exhibited the greatest DHA production potential and was selected for further investigation. The effects of different light intensities, forms, and concentrations of nitrogen, phosphorus, and salinity on growth and DHA production of I. galbana #153180 were studied in a bubble column photobioreactor (PBR). Under favorable culture conditions, I. galbana #153180 contained DHA up to 17.5 % of total fatty acids or 1.7 % of cell dry weight. I. galbana #153180 was further tested in outdoor flat-plate PBRs varying in light path length, starting cell density (SCD), and culture mode (batch versus semicontinuous). When optimized, record high biomass and DHA productivity of I. galbana #153180 of 0.72 g L(-1) day(-1) and 13.6 mg L(-1) day(-1), or 26.4 g m(-2) day(-1) and 547.7 mg m(-2) day(-1), respectively, were obtained, suggesting that I. galbana #153180 may be a desirable strain for commercial production of DHA.

  15. Surface (glyco-)proteins: primary structure and crystallization under microgravity conditions

    Science.gov (United States)

    Claus, H.; Akca, E.; Schultz, N.; Karbach, G.; Schlott, B.; Debaerdemaeker, T.; De Clercq, J.-P.; König, H.

    2001-08-01

    The Archaea comprise microorganisms that live under environmental extremes, like high temperature, low pH value or high salt concentration. Their cells are often covered by a single layer of (glyco)protein subunits (S-layer) in hexagonal arrangement. In order to get further hints about the molecular mechanisms of protein stabilization we compared the primary and secondary structures of archaeal S-layer (glyco)proteins. We found an increase of charged amino acids in the S-layer proteins of the extreme thermophilic species compared to their mesophilic counterparts. Our data and those of other authors suggest that ionic interactions, e.g., salt bridges seem to be played a major role in protein stabilization at high temperatures. Despite the differences in the growth optima and the predominance of some amino acids the primary structures of S-layers revealed also a significant degree of identity between phylogenetically related archaea. These obervations indicate that protein sequences of S-layers have been conserved during the evolution from extremely thermophilic to mesophilic life. To support these findings the three-dimensional structure of the S-layer proteins has to be elucidated. Recently, we described the first successful crystallization of an extreme thermophilic surface(glyco)protein under microgravity conditions.

  16. Flight Experiments of Physical Vapor Transport of ZnSe: Growth of Crystals in Various Convective Conditions

    Science.gov (United States)

    Su, Ching-Hua

    2015-01-01

    A low gravity material experiment will be performed in the Material Science Research Rack (MSRR) on International Space Station (ISS). The flight experiment will conduct crystal growths of ZnSe and related ternary compounds, such as ZnSeS and ZnSeTe, by physical vapor transport (PVT). The main objective of the project is to determine the relative contributions of gravity-driven fluid flows to the compositional distribution, incorporation of impurities and defects, and deviation from stoichiometry observed in the grown crystals as results of buoyancy-driven convection and growth interface fluctuations caused by irregular fluid-flows on Earth. The investigation consists of extensive ground-based experimental and theoretical research efforts and concurrent flight experimentation. The objectives of the ground-based studies are (1) obtain the experimental data and conduct the analyses required to define the optimum growth parameters for the flight experiments, (2) perfect various characterization techniques to establish the standard procedure for material characterization, (3) quantitatively establish the characteristics of the crystals grown on Earth as a basis for subsequent comparative evaluations of the crystals grown in a low-gravity environment and (4) develop theoretical and analytical methods required for such evaluations. ZnSe and related ternary compounds have been grown by vapor transport technique with real time in-situ non-invasive monitoring techniques. The grown crystals have been characterized extensively by various techniques to correlate the grown crystal properties with the growth conditions. This talk will focus on the ground-based studies on the PVT crystal growth of ZnSe and related ternary compounds, especially the effects of different growth orientations related to gravity direction on the grown crystals.

  17. Experimental Conditions to Obtain Photopolymerization Induced Phase Separation Process in Liquid Crystal-Photopolymer Composite Materials under Laser Exposure

    Directory of Open Access Journals (Sweden)

    Manuel Ortuño

    2014-01-01

    Full Text Available We analyze the experimental conditions necessary to obtain a photopolymerization induced phase separation process inside liquid crystal-photopolymer composite materials. Composites stored for 24 hours perform poorly in hologram recording but a good result is obtained if they are used recently prepared. We use a procedure combining heat and sonication to disarrange the liquid crystal structures formed during storage of the composite. We also propose incoherent light treatment after recording the hologram in order to evaluate if the phase separation evolved correctly during hologram recording.

  18. Synergetic crystallization in a Nd2Fe14B/α-Fe nanocomposite under electron beam exposure conditions.

    Science.gov (United States)

    Tian, Haidong; Zhang, Yinfeng; Han, Jingzhi; Xu, Zhuang; Zhang, Xiaodong; Liu, Shunquan; Wang, Changsheng; Yang, Yingchang; Han, Li; Yang, Jinbo

    2016-10-27

    Nd2Fe14B/α-Fe nanocomposite magnets are prepared through electron beam exposure with a greatly reduced annealing time of 0.1 s. This is by far the most effective approach due to the effect of an extremely high heating rate featuring a rapid thermal process. The impact that the rapid thermal process has on crystallization is expounded by the introduction of the Landau model and Langevin dynamical simulations. The change of crystallization sequence from the α-Fe phase preceding the Nd2Fe14B phase under conventional annealing conditions, to synergetic crystallization under electron beam conditions is investigated. Synergetic crystallization results in more intense interaction between the α-Fe phase and the Nd2Fe14B phase in order to refine the microstructure as the fraction of Fe increases within our addition range. Improved uniformity, and shifts in the microstructure and distribution of the α-Fe phase contribute to the improvement of the magnetic properties. Compared with conventional furnace annealing ones, the magnetic properties of samples under electron beam exposure conditions are improved. For the Nd10Fe83.3B6.2Nb0.2Ga0.3 alloy, coercivity is enhanced from 4.56 kOe to 6.73 kOe, remanence ratio increases from 0.75 to 0.79, and a superior squareness of the hysteresis loop is achieved.

  19. Influence of intermediate layers on the surface condition of laser crystallized silicon thin films and solar cell performance

    Science.gov (United States)

    Höger, Ingmar; Himmerlich, Marcel; Gawlik, Annett; Brückner, Uwe; Krischok, Stefan; Andrä, Gudrun

    2016-01-01

    The intermediate layer (IL) between glass substrate and silicon plays a significant role in the optimization of multicrystalline liquid phase crystallized silicon thin film solar cells on glass. This study deals with the influence of the IL on the surface condition and the required chemical surface treatment of the crystallized silicon (mc-Si), which is of particular interest for a-Si:H heterojunction thin film solar cells. Two types of IL were investigated: sputtered silicon nitride (SiN) and a layer stack consisting of silicon nitride and silicon oxide (SiN/SiO). X-ray photoelectron spectroscopy measurements revealed the formation of silicon oxynitride (SiOxNy) or silicon oxide (SiO2) layers at the surface of the mc-Si after liquid phase crystallization on SiN or SiN/SiO, respectively. We propose that SiOxNy formation is governed by dissolving nitrogen from the SiN layer in the silicon melt, which segregates at the crystallization front during crystallization. This process is successfully hindered, when additional SiO layers are introduced into the IL. In order to achieve solar cell open circuit voltages above 500 mV, a removal of the formed SiOxNy top layer is required using sophisticated cleaning of the crystallized silicon prior to a-Si:H deposition. However, solar cells crystallized on SiN/SiO yield high open circuit voltage even when a simple wet chemical surface treatment is applied. The implementation of SiN/SiO intermediate layers facilitates the production of mesa type solar cells with open circuit voltages above 600 mV and a power conversion efficiency of 10%.

  20. Influence of intermediate layers on the surface condition of laser crystallized silicon thin films and solar cell performance

    Energy Technology Data Exchange (ETDEWEB)

    Höger, Ingmar, E-mail: ingmar.hoeger@ipht-jena.de; Gawlik, Annett; Brückner, Uwe; Andrä, Gudrun [Leibniz-Institut für Photonische Technologien, PF 100239, 07702 Jena (Germany); Himmerlich, Marcel; Krischok, Stefan [Institut für Mikro-und Nanotechnologien, Technische Universität Ilmenau, PF 100565, 98684 Ilmenau (Germany)

    2016-01-28

    The intermediate layer (IL) between glass substrate and silicon plays a significant role in the optimization of multicrystalline liquid phase crystallized silicon thin film solar cells on glass. This study deals with the influence of the IL on the surface condition and the required chemical surface treatment of the crystallized silicon (mc-Si), which is of particular interest for a-Si:H heterojunction thin film solar cells. Two types of IL were investigated: sputtered silicon nitride (SiN) and a layer stack consisting of silicon nitride and silicon oxide (SiN/SiO). X-ray photoelectron spectroscopy measurements revealed the formation of silicon oxynitride (SiO{sub x}N{sub y}) or silicon oxide (SiO{sub 2}) layers at the surface of the mc-Si after liquid phase crystallization on SiN or SiN/SiO, respectively. We propose that SiO{sub x}N{sub y} formation is governed by dissolving nitrogen from the SiN layer in the silicon melt, which segregates at the crystallization front during crystallization. This process is successfully hindered, when additional SiO layers are introduced into the IL. In order to achieve solar cell open circuit voltages above 500 mV, a removal of the formed SiO{sub x}N{sub y} top layer is required using sophisticated cleaning of the crystallized silicon prior to a-Si:H deposition. However, solar cells crystallized on SiN/SiO yield high open circuit voltage even when a simple wet chemical surface treatment is applied. The implementation of SiN/SiO intermediate layers facilitates the production of mesa type solar cells with open circuit voltages above 600 mV and a power conversion efficiency of 10%.

  1. Neurological Condition of Infants Born After In Vitro Fertilization With Preimplantation Genetic Screening

    NARCIS (Netherlands)

    Middelburg, Karin J.; Heineman, Maas J.; Haadsma, Maaike L.; Bos, Arend F.; Kok, Joke H.; Hadders-Algra, Mijna

    2010-01-01

    Aim of this study was to evaluate the effect of preimplantation genetic screening (PGS) on neurodevelopmental outcome in children. We conducted a prospective follow-up Study of children born to women randomly assigned to in vitro fertilization with or without PGS. Primary outcome was adverse neurolo

  2. Modeling nanoscale gas sensors under realistic conditions: Computational screening of metal-doped carbon nanotubes

    DEFF Research Database (Denmark)

    García Lastra, Juan Maria; Mowbray, Duncan; Thygesen, Kristian Sommer

    2010-01-01

    We use computational screening to systematically investigate the use of transition-metal-doped carbon nanotubes for chemical-gas sensing. For a set of relevant target molecules (CO, NH3, and H2S) and the main components of air (N2, O2, and H2O), we calculate the binding energy and change...

  3. Carboxylic acids in crystallization of macromolecules: learning from successful crystallization experiments.

    Science.gov (United States)

    Offermann, Lesa R; He, John Z; Mank, Nicholas J; Booth, William T; Chruszcz, Maksymilian

    2014-03-01

    The production of macromolecular crystals suitable for structural analysis is one of the most important and limiting steps in the structure determination process. Often, preliminary crystallization trials are performed using hundreds of empirically selected conditions. Carboxylic acids and/or their salts are one of the most popular components of these empirically derived crystallization conditions. Our findings indicate that almost 40 % of entries deposited to the Protein Data Bank (PDB) reporting crystallization conditions contain at least one carboxylic acid. In order to analyze the role of carboxylic acids in macromolecular crystallization, a large-scale analysis of the successful crystallization experiments reported to the PDB was performed. The PDB is currently the largest source of crystallization data, however it is not easily searchable. These complications are due to a combination of a free text format, which is used to capture information on the crystallization experiments, and the inconsistent naming of chemicals used in crystallization experiments. Despite these difficulties, our approach allows for the extraction of over 47,000 crystallization conditions from the PDB. Initially, the selected conditions were investigated to determine which carboxylic acids or their salts are most often present in crystallization solutions. From this group, selected sets of crystallization conditions were analyzed in detail, assessing parameters such as concentration, pH, and precipitant used. Our findings will lead to the design of new crystallization screens focused around carboxylic acids.

  4. Two Beam Energy Exchange in Hybrid Liquid Crystal Cells with Photorefractive Field Controlled Boundary Conditions (Postprint)

    Science.gov (United States)

    2016-09-12

    AFRL-RX-WP-JA-2017-0209 TWO BEAM ENERGY EXCHANGE IN HYBRID LIQUID CRYSTAL CELLS WITH PHOTOREFRACTIVE FIELD CONTROLLED BOUNDARY...DATES COVERED (From - To) 29 August 2016 Interim 26 October 2015 – 29 July 2016 4. TITLE AND SUBTITLE TWO BEAM ENERGY EXCHANGE IN HYBRID LIQUID... energy gain when two light beams intersect in a hybrid nematic liquid crystal (LC) cell with photorefractive crystalline substrates. A periodic space

  5. Inhibition of calcium carbonate crystal growth by organic additives using the constant composition method in conditions of recirculating cooling circuits

    Science.gov (United States)

    Chhim, Norinda; Kharbachi, Chams; Neveux, Thibaut; Bouteleux, Céline; Teychené, Sébastien; Biscans, Béatrice

    2017-08-01

    The cooling circuits used in power plants are subject to mineral crystallization which can cause scaling on the surfaces of equipment and construction materials reducing their heat exchange efficiency. Precipitated calcium carbonate is the predominant mineral scale commonly observed in cooling systems. Supersaturation is the key parameter controlling the nucleation and growth of calcite in these systems. The present work focuses on the precipitation of calcite using the constant composition method at constant supersaturation, through controlled addition of reactants to a semi-batch crystallizer, in order to maintain constant solution pH. The determination of the thermodynamic driving force (supersaturation) was based on the relevant chemical equilibria, total alkalinity and calculation of the activity coefficients. Calcite crystallization rates were derived from the experiments performed at supersaturation levels similar to those found in industrial station cooling circuits. Several types of seeds particles were added into the aqueous solution to mimic natural river water conditions in terms of suspended particulate matters content, typically: calcite, silica or illite particles. The effect of citric and copolycarboxylic additive inhibitors added to the aqueous solution was studied. The calcium carbonate growth rate was reduced by 38.6% in the presence of the citric additive and a reduction of 92.7% was observed when the copolycarboxylic additive was used under identical experimental conditions. These results are explained by the location of the adsorbed inhibitor at the crystal surface and by the degree of chemical bonding to the surface.

  6. Novel Gyroscopic Mounting for Crystal Oscillators to Increase Short and Medium Term Stability under Highly Dynamic Conditions

    Directory of Open Access Journals (Sweden)

    Maryam Abedi

    2015-06-01

    Full Text Available In this paper, a gyroscopic mounting method for crystal oscillators to reduce the impact of dynamic loads on their output stability has been proposed. In order to prove the efficiency of this mounting approach, each dynamic load-induced instability has been analyzed in detail. A statistical study has been performed on the elevation angle of the g-sensitivity vector of Stress Compensated-cut (SC-cut crystals. The analysis results show that the proposed gyroscopic mounting method gives good performance for host vehicle attitude changes. A phase noise improvement of 27 dB maximum and 5.7 dB on average can be achieved in the case of steady state loads, while under sinusoidal vibration conditions, the maximum and average phase noise improvement are as high as 24 dB and 7.5 dB respectively. With this gyroscopic mounting method, random vibration-induced phase noise instability is reduced 30 dB maximum and 8.7 dB on average. Good effects are apparent for crystal g-sensitivity vectors with low elevation angle φ and azimuthal angle β. under highly dynamic conditions, indicating the probability that crystal oscillator instability will be significantly reduced by using the proposed mounting approach.

  7. Chemical conversion of cisplatin and carboplatin with histidine in a model protein crystallized under sodium iodide conditions

    Energy Technology Data Exchange (ETDEWEB)

    Tanley, Simon W. M.; Helliwell, John R., E-mail: john.helliwell@manchester.ac.uk [University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom)

    2014-08-29

    Crystals of HEWL with cisplatin and HEWL with carboplatin grown in sodium iodide conditions both show a partial chemical transformation of cisplatin or carboplatin to a transiodoplatin (PtI{sub 2}X{sub 2}) form. The binding is only at the N{sup δ} atom of His15. A further Pt species (PtI{sub 3}X) is also seen, in both cases bound in a crevice between symmetry-related protein molecules. Cisplatin and carboplatin are platinum anticancer agents that are used to treat a variety of cancers. Previous X-ray crystallographic studies of carboplatin binding to histidine in hen egg-white lysozyme (HEWL) showed a partial chemical conversion of carboplatin to cisplatin owing to the high sodium chloride concentration used in the crystallization conditions. Also, the co-crystallization of HEWL with carboplatin in sodium bromide conditions resulted in the partial conversion of carboplatin to the transbromoplatin form, with a portion of the cyclobutanedicarboxylate (CBDC) moiety still present. The results of the co-crystallization of HEWL with cisplatin or carboplatin in sodium iodide conditions are now reported in order to determine whether the cisplatin and carboplatin converted to the iodo form, and whether this took place in a similar way to the partial conversion of carboplatin to cisplatin in NaCl conditions or to transbromoplatin in NaBr conditions as seen previously. It is reported here that a partial chemical transformation has taken place to a transplatin form for both ligands. The NaI-grown crystals belonged to the monoclinic space group P2{sub 1} with two molecules in the asymmetric unit. The chemically transformed cisplatin and carboplatin bind to both His15 residues, i.e. in each asymmetric unit. The binding is only at the N{sup δ} atom of His15. A third platinum species is also seen in both conditions bound in a crevice between symmetry-related molecules. Here, the platinum is bound to three I atoms identified based on their anomalous difference electron densities

  8. Use of Chromophoric Ligands to Visually Screen Co-crystals of Putative Protein-Nucleic Acid Complexes

    Science.gov (United States)

    Jiang, Xiaohua; Egli, Martin

    2011-01-01

    Distinguishing between crystals of protein-nucleic acid complexes and those containing protein alone is a common problem in structural studies of protein-nucleic acid interactions. Currently there are several methods available for detecting nucleic acid in crystals, including gel electrophoresis, SYBR Gold fluorescence dye staining and methyl violet staining. However, they require either that the crystals be sacrificed or access to a fluorescence microscope. In this protocol, we describe an approach that allows direct visualization of either the presence or absence of oligonucleotides in crystals grown from solutions containing both protein and nucleic acid – labeling with the Cy5 dye. In addition to offering the advantage of being able to distinguish between crystals of complex and protein alone with the naked eye or a light microscope, crystals of covalently Cy5-labeled DNA can be directly used for X-ray diffraction data collection. PMID:21901673

  9. A novel way to grow hemozoin-like crystals in vitro and its use to screen for hemozoin inhibiting antimalarial compounds.

    Directory of Open Access Journals (Sweden)

    Vincent Thomas

    Full Text Available BACKGROUND: Hemozoin crystals are normally formed in vivo by Plasmodium parasites to detoxify free heme released after hemoglobin digestion during its intraerythrocytic stage. Inhibition of hemozoin formation by various drugs results in free heme concentration toxic for the parasites. As a consequence, in vitro assays have been developed to screen and select candidate antimalarial drugs based on their capacity to inhibit hemozoin formation. In this report we describe new ways to form hemozoin-like crystals that were incidentally discovered during research in the field of prion inactivation. METHODS: We investigated the use of a new assay based on naturally occurring "self-replicating" particles and previously described as presenting resistance to decontamination comparable to prions. The nature of these particles was determined using electron microscopy, Maldi-Tof analysis and X-ray diffraction. They were compared to synthetic hemozoin and to hemozoin obtained from Plasmodium falciparum. We then used the assay to evaluate the capacity of various antimalarial and anti-prion compounds to inhibit "self-replication" (crystallisation of these particles. RESULTS: We identified these particles as being similar to ferriprotoporphyrin IX crystal and confirmed the ability of these particles to serve as nuclei for growth of new hemozoin-like crystals (HLC. HLC are morphologically similar to natural and synthetic hemozoin. Growth of HLC in a simple assay format confirmed inhibition by quinolines antimalarials at potencies described in the literature. Interestingly, artemisinins and tetracyclines also seemed to inhibit HLC growth. CONCLUSIONS: The described HLC assay is simple and easy to perform and may have the potential to be used as an additional tool to screen antimalarial drugs for their hemozoin inhibiting activity. As already described by others, drugs that inhibit hemozoin crystal formation have also the potential to inhibit misfolded proteins

  10. Crystallization and cooling conditions for diogenite formation in the turbulent magma ocean of asteroid 4 Vesta

    Science.gov (United States)

    Kawabata, Yusuke; Nagahara, Hiroko

    2017-01-01

    Despite its small size, the asteroid 4 Vesta has been completely differentiated to core and mantle. Its composition is similar to howardite-eucrite-diogenite (HED) meteorites of which the detailed petrology is known. Therefore, 4 Vesta is a good target for understanding the differentiation of terrestrial planets. A new differentiation model for crust formation has been developed by taking magma ocean fluid dynamics, chemical equilibrium, the presence of 26Al, and cooling into consideration with a special focus on crystal separation. The role of crystal size, thickness of the conductive lid, and fO2 are evaluated as parameters. The results show that large crystals of at least 1 cm settled and formed a kilometer-thick cumulate layer of orthopyroxene with Mg # of 0.70-0.90 in ∼20 thousand years, which almost agrees with the Mg # of diogenites. Smaller grain sizes formed thinner layers.

  11. Re-investigation of the crystal structure of enstatite under high-pressure conditions

    DEFF Research Database (Denmark)

    Periotto, Benedetta; Balic Zunic, Tonci; Nestola, Fabrizio

    2012-01-01

    A synthetic single crystal of pure orthoenstatite (MgSiO3, space group Pbca) has been investigated at high pressure for structural determinations by in situ single-crystal X‑ray diffraction using a diamond-anvil cell. Ten complete intensity data collections were performed up to 9.36 GPa. This study...... is mostly governed by significant volume decrease of the Mg1 and Mg2 octahedra, affecting in turn the kink of the tetrahedral chains, especially the TB chain of larger SiO4 tetrahedra. The Mg2 polyhedron undergoes the largest volume variation, 8.7%, due especially to the strong contraction of the longest...

  12. Existing conditions of full bandgaps and absolute negative refraction in metallic-dielectric photonic crystal

    Institute of Scientific and Technical Information of China (English)

    Dong Jian-Wen; Hu Xin-Hua; Wang He-Zhou

    2007-01-01

    This paper has theoretically studied the characteristic frequencies of band structures in two-dimensional metallicdielectric photonic crystals. It is demonstrated that a large filling fraction benefits the existence of absolute photonic band gap, while a smaller filling fraction benefits an absolute negative refraction band. In addition, it also finds that the relation between the cut-off frequency of E-polarized wave and the filling fraction exceeding 10% is content with a linear increasing function, whose coefficients are exponential to the normalized lattice constant. These investigations have significant implications for tuning the operational frequencies to desired applications and manufacturing photonic crystals.

  13. Crystallization and Thermoelectric Transport in Semiconductor Micro- and Nanostructures Under Extreme Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gokirmak, Ali [Univ. of Connecticut, Storrs, CT (United States); Silva, Helena [Univ. of Connecticut, Storrs, CT (United States)

    2017-08-30

    This project focused on thermoelectric transport in semiconductor micro and nanostructures where moderate and typical operating voltages and currents lead to extreme thermal gradients and current densities. Models that describe behavior of semiconducting materials typically assume an equilibrium condition or slight deviations from it. In these cases the generation-recombination processes are assumed to have reached a local equilibrium for a given temperature. Hence, free carrier concentrations and their mobilities, band-gap, thermal conductivity, thermoelectric properties, mobility of atoms and mechanical properties of the material, can be described as a function of temperature. In the case of PN junctions under electrical bias, carrier concentrations can change up to ~ 1020 cm-3 and a drift-diffusion approximation is typically used to obtain the carrier concentrations while assuming that the material properties do not change. In non-equilibrium conditions, the assumption that the material properties remain the same may not be valid. While the increased conduction-band electron concentration may not have a drastic effect on the material, large hole concentration is expected to soften the material as ‘a hole’ comes into existence as a broken bond in the lattice. As the hole density approaches 1022 cm-3, the number of bonds holding the lattice together is significantly reduced, making it easier to break additional bonds, reduce band-gap and inhibit phonon transport. As these holes move away from where they were generated, local properties are expected to deviate significantly from the equilibrium case. Hence, temperature alone is not sufficient to describe the behavior of the material. The behavior of the solid material close to a molten region (liquid-solid interfaces) is also expected to deviate from the equilibrium case as a function of hole injection rate, which can be drastically increased or decreased in the presence of an electric field. In the past years

  14. Depression Screening

    Science.gov (United States)

    ... Centers Diseases + Condition Centers Mental Health Medical Library Depression Screening (PHQ-9) - Instructions The following questions are ... this tool, there is also text-only version . Depression Screening - Manual Instructions The following questions are a ...

  15. Increase on the initial soluble heme levels in acidic conditions is an important mechanism for spontaneous heme crystallization in vitro.

    Directory of Open Access Journals (Sweden)

    Renata Stiebler

    Full Text Available BACKGROUND: Hemozoin (Hz is a heme crystal that represents a vital pathway for heme disposal in several blood-feeding organisms. Recent evidence demonstrated that β-hematin (βH (the synthetic counterpart of Hz formation occurs under physiological conditions near synthetic or biological hydrophilic-hydrophobic interfaces. This seems to require a heme dimer acting as a precursor of Hz crystals that would be formed spontaneously in the absence of the competing water molecules bound to the heme iron. Here, we aimed to investigate the role of medium polarity on spontaneous βH formation in vitro. METHODOLOGY/PRINCIPAL FINDINGS: We assessed the effect of water content on spontaneous βH formation by using the aprotic solvent dimethylsulfoxide (DMSO and a series of polyethyleneglycols (PEGs. We observed that both DMSO and PEGs (3.350, 6.000, 8.000, and 22.000 increased the levels of soluble heme under acidic conditions. These compounds were able to stimulate the production of βH crystals in the absence of any biological sample. Interestingly, the effects of DMSO and PEGs on βH formation were positively correlated with their capacity to promote previous heme solubilization in acidic conditions. Curiously, a short chain polyethyleneglycol (PEG 300 caused a significant reduction in both soluble heme levels and βH formation. Finally, both heme solubilization and βH formation strongly correlated with reduced medium water activity provided by increased DMSO concentrations. CONCLUSIONS: The data presented here support the notion that reduction of the water activity is an important mechanism to support spontaneous heme crystallization, which depends on the previous increase of soluble heme levels.

  16. Influence of rotating magnetic fields on THM growth of CdZnTe crystals under microgravity and ground conditions

    Science.gov (United States)

    Stelian, Carmen; Duffar, Thierry

    2015-11-01

    The influence of rotating magnetic fields (RMF) on species transport and interface stability during the growth of Cd0.96Zn0.04Te:In crystals by using the traveling heater method (THM), under microgravity and terrestrial conditions, is numerically investigated. The numerical results are compared to ground and space experiments. The modeling of THM under ground conditions shows very deleterious effects of the natural convection on the morphological stability of the growth interface. The vertical flow transports the liquid of low Te concentration from the dissolution interface to the growth interface, which is consequently destabilized. The suppression of this flow, in low-gravity conditions, results in higher morphological stability of the growth interface. Application of RMF induces a two flow cell pattern, which has a destabilizing effect on the growth interface. Simulations performed by varying the magnetic field induction in the range of 1 - 3 mT show optimal conditions for the growth with a stable interface at low strength of the magnetic field (B = 1 mT). Computations of indium distribution show a better homogeneity of crystals grown under purely diffusive conditions. Rotating magnetic fields of B = 1 mT induce low intensity convection, which generates concentration gradients near the growth interface. These numerical results are in agreement with experiments performed during the FOTON M4 space mission, showing good structural quality of Cd0.96Zn0.04Te crystals grown at very low gravity level. Applying low intensity rotating magnetic fields in ground experiments has no significant influence on the flow pattern and solute distribution. At high intensity of RMF (B = 50 mT), the buoyancy convection is damped near the growth front, resulting in a more stable advancing interface. However, convection is strengthening in the upper part of the liquid zone, where the flow becomes unsteady. The multi-cellular unsteady flow generates temperature oscillations, having

  17. Dip-pen nanolithography-assisted protein crystallization.

    Science.gov (United States)

    Ielasi, Francesco S; Hirtz, Michael; Sekula-Neuner, Sylwia; Laue, Thomas; Fuchs, Harald; Willaert, Ronnie G

    2015-01-14

    We demonstrate the use of dip-pen nanolithography (DPN) to crystallize proteins on surface-localized functionalized lipid layer arrays. DOPC lipid layers, containing small amounts of biotin-DOPE lipid molecules, were printed on glass substrates and evaluated in vapor diffusion and batch crystallization screening setups, where streptavidin was used as a model protein for crystallization. Independently of the crystallization system used and the geometry of the lipid layers, nucleation of streptavidin crystals occurred specifically on the DPN-printed biotinylated structures. Protein crystallization on lipid array patches is also demonstrated in a microfluidic chip, which opens the way toward high-throughput screening to find suitable nucleation and crystal growth conditions. The results demonstrate the use of DPN in directing and inducing protein crystallization on specific surface locations.

  18. Study on Screening and Cultivation Conditions of Xylanase-Producing Alkalophilic Bacterial

    Institute of Scientific and Technical Information of China (English)

    Han Xiao-fang; Zheng Lian-shuang; Xie Yi-min

    2004-01-01

    An xylanase producting alkalophilic Bacillus NT-9 was obtaind by the screening method of transparent zone on the selective medium, and the effects of carbon source and nitrogen source on xylanase production were studied. The medium composed of xylose 1.5%, (NH4)2SO4 0.25%, K2HPO4 0.1%, MgSO4·7H2O 0.02%, with the initial pH of 10, was suggested to be optimal for the enzyme production in this study. When cultivatied at 37 ℃ for 72 h, the enzyme activity elaborated by the strain may reach as high as 10.5 U/mL. The xylanase produced by Bacillus NT-9 was a constituent enzyme.

  19. Screening on DHA-producing Antarctic bacteria N- 6 and its cultural conditions

    Institute of Scientific and Technical Information of China (English)

    Zhang Botao; Miao Jin-lai; Hui Hanxing; Wang Qing

    2006-01-01

    In Antarctic, the geography and climate differs from those in other places,and the bacteria there have adapted well to the environment there. Two hundred strains of bacteria were isolated from the sea ice in Antarctica. The bacteria were screened for DHA by means of GC, with fish oil as the standard. Seven strains containing DHA or EPA were obtained, among which the strain of No. N-6 was outstanding. And the component of DHA was identified by GC-MS. The relative content of DHA in N-6 was 8.72%, and total lipids in dry bacteria was 22.54%. The effects of some factors, including temperature, salinity and pH value, on the growth and DHAcontent of strain N-6 were studied. The results show that the DHA-content is relatively high when in low temperature and high pH, and the bacterium is psychrophilic, alkalophilic.

  20. A conditional piggyBac transposition system for genetic screening in mice identifies oncogenic networks in pancreatic cancer.

    Science.gov (United States)

    Rad, Roland; Rad, Lena; Wang, Wei; Strong, Alexander; Ponstingl, Hannes; Bronner, Iraad F; Mayho, Matthew; Steiger, Katja; Weber, Julia; Hieber, Maren; Veltkamp, Christian; Eser, Stefan; Geumann, Ulf; Öllinger, Rupert; Zukowska, Magdalena; Barenboim, Maxim; Maresch, Roman; Cadiñanos, Juan; Friedrich, Mathias; Varela, Ignacio; Constantino-Casas, Fernando; Sarver, Aaron; Ten Hoeve, Jelle; Prosser, Haydn; Seidler, Barbara; Bauer, Judith; Heikenwälder, Mathias; Metzakopian, Emmanouil; Krug, Anne; Ehmer, Ursula; Schneider, Günter; Knösel, Thomas; Rümmele, Petra; Aust, Daniela; Grützmann, Robert; Pilarsky, Christian; Ning, Zemin; Wessels, Lodewyk; Schmid, Roland M; Quail, Michael A; Vassiliou, George; Esposito, Irene; Liu, Pentao; Saur, Dieter; Bradley, Allan

    2015-01-01

    Here we describe a conditional piggyBac transposition system in mice and report the discovery of large sets of new cancer genes through a pancreatic insertional mutagenesis screen. We identify Foxp1 as an oncogenic transcription factor that drives pancreatic cancer invasion and spread in a mouse model and correlates with lymph node metastasis in human patients with pancreatic cancer. The propensity of piggyBac for open chromatin also enabled genome-wide screening for cancer-relevant noncoding DNA, which pinpointed a Cdkn2a cis-regulatory region. Histologically, we observed different tumor subentities and discovered associated genetic events, including Fign insertions in hepatoid pancreatic cancer. Our studies demonstrate the power of genetic screening to discover cancer drivers that are difficult to identify by other approaches to cancer genome analysis, such as downstream targets of commonly mutated human cancer genes. These piggyBac resources are universally applicable in any tissue context and provide unique experimental access to the genetic complexity of cancer.

  1. Systematic Review of Screening Instruments for Psychosocial Problems in Children and Adolescents With Long-Term Physical Conditions

    Science.gov (United States)

    Thabrew, Hiran; McDowell, Heather; Given, Katherine; Murrell, Kathryn

    2017-01-01

    Children and adolescents with long-term physical conditions (LTPCs) are at greater risk of developing psychosocial problems. Screening for such problems may be undertaken using validated psychometric instruments to facilitate early intervention. A systematic review was undertaken to identify clinically utilized and psychometrically validated instruments for identifying depression, anxiety, behavior problems, substance use problems, family problems, and multiple problems in children and adolescents with LTPCs. Comprehensive searches of articles published in English between 1994 and 2014 were completed via Medline, Embase, PsycINFO, CINAHL, and Cochrane CENTRAL databases, and by examining reference lists of identified articles and previous related reviews. Forty-four potential screening instruments were identified, described, and evaluated against predetermined clinical and psychometric criteria. Despite limitations in the evidence regarding their clinical and psychometric validity in this population, a handful of instruments, available at varying cost, in multiple languages and formats, were identified to support targeted, but not universal, screening for psychosocial problems in children and adolescents with LTPCs.

  2. Geochemistry of the Topuk Pluton associated with the Kozbudaklar W-skarn deposit (Western Anatolia, Turkey): Implication for crystallization conditions

    Science.gov (United States)

    Orhan, Ayşe; Demirbilek, Mehmet; Mutlu, Halim

    2017-06-01

    The Kozbudaklar scheelite-bearing skarn deposit in the Tavşanlı Zone, western Turkey, occurs at the contact between Eocene Topuk pluton and Triassic İnönü marble of calcic character. The Topuk pluton is medium-coarse grained, granodiorite in composition and has a hypidiomorphic equigranular texture. The host rock contains mafic microgranular enclaves (MME) of monzodiorite-monzogabbro composition and is interrupted by porphyritic granodiorite and granite-aplite vein rocks. The pluton is calk-alkaline, metaluminous and composed of I-type melt character. δ18O and δD compositions of silicate minerals from granodioritic host rock are 5.9-10.6‰ and -77.0 to -71.4‰ and conformable with the range of unaltered I-type granites. Trace element contents indicate that pluton is crystallized from mantle-derived magma interacted with continental crust in a volcanic arc or subduction related setting. Major and trace element concentrations of Topuk pluton are quite consistent with geochemical patterns of Cu-skarn granitoids. Results of mineral chemistry analysis of the pluton yield that plagioclases are of oligoclase-andesine, amphiboles are of magnesio-hornblende and biotites are of ferro-magnesian composition. Amphiboles and biotites of granodioritic host rock are represented by calc-alkaline, I-type melt composition evolved in a subduction environment. Based on the results of plagioclase-Al in hornblende and amphibole chemistry data from the pluton, two different stages are proposed for the magma crystallization. The first stage was developed in a relatively deeper environment (>15 km) under high pressure (>4 kbar) and low log ƒO2 (>-17.6) conditions which reflect fractional crystallization and magma-mixing depth of basaltic magma and these conditions are not correlated with scheelite mineralization. The second crystallization stage of magma which proceeded at shallow depths (-12.9 to -11.0) values are accompanied by high H2O contents (5.39-6.88 wt.%). High water

  3. Screening a Strain of Aspergillus niger and Optimization of Fermentation Conditions for Degradation of Aflatoxin B1

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2014-11-01

    Full Text Available Aflatoxin B1, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1 was able to degrade aflatoxin B1 after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis on the basis of 18S rDNA, could remove 26.3% of aflatoxin B1 after 48 h of fermentation in nutrient broth (NB. Optimization of fermentation conditions for aflatoxin B1 degradation by selected Aspergillus niger was also performed. These results showed that 58.2% of aflatoxin B1 was degraded after 24 h of culture under the optimal fermentation conditions. The aflatoxin B1 degradation activity of Aspergillus niger supernatant was significantly stronger than cells and cell extracts. Furthermore, effects of temperature, heat treatment, pH, and metal ions on aflatoxin B1 degradation by the supernatant were examined. Results indicated that aflatoxin B1 degradation of Aspergillus niger is enzymatic and this process occurs in the extracellular environment.

  4. Late magmatic stage of the zoned Caleu pluton (Central Chile): insights from zircon crystallization conditions

    Science.gov (United States)

    Molina, P. G.; Parada, M.; Gutierrez, F. J.; Chang-Qiang, M.; Jianwei, L.; Yuanyuan, L.

    2012-12-01

    The Caleu pluton consists of three N-S elongated lithological zones: Gabbro-Diorite Zone (GDZ), Tonalite Zone (TZ) and Granodiorite Zone (GZ); western, middle and eastern portions of the pluton, respectively. The zones are thought to be previously differentiated in a common, isotopically depleted (Sr-Nd), subjacent magma reservoir at a 4 kbar equivalent depth. The emplacement should have occurred at the climax of the Cretaceous rifting. We present preliminary results of U238/Pb206 zircon geochronology; zircon saturation, Tsat(Zrn), and crystallization temperatures (Ti-in-Zrn); as well as relative oxidation states at time of crystallization, based on: (i) the sluggish REE and HFSE subsolidus diffusivities in zircon; (ii) the behavior of Ti4+↔Si4+ and Ce4+↔Zr4+ isovalent replacement, in addition to a constrained TiO2 activity in almost all typical crustal rocks; and (iii) relative oxidation states at time of crystallization, respectively. The latter are obtained by interpolation of the partition coefficients of trivalent (REE) and tetravalent (HFSE) curves in Onuma diagrams for each zircon, and then estimating relative Ce(IV)/Ce(III) ratios. Results obtained from 4 samples (a total of 77 zircon grains) collected from the three mentioned lithological zones indicate U/Pb ages of approximately 99.5 ±1.5 Ma, 96.8 ±0.6 Ma, and 94.4 +2.2 -0.8 Ma; and Ti-in Zrn ranges of ca. 720-870°C, ca. 680-820°C and ca. 750-840°C, for the GDZ, TZ and GZ samples, respectively. On the other hand Tsat(Zrn) of ca. 750-780°C in the TZ, and ca. 830-890°C in the GZ, were obtained. As expected saturation temperatures are similar or higher than Ti-in-Zrn obtained in zircon grains of TZ and GZ, respectively. Cathodoluminiscence images in zircon suggest a magmatic origin, due to absence of complex zoning patterns and fairly well conserved morphologies. Exceptionally the GDZ sample zircons show evidence of inheritance, indicating a xenocrystic and/or antecrystic origin. A relative Ce

  5. Screen of Different Cotton Varieties under Dry Land Conditions in Namibia

    Institute of Scientific and Technical Information of China (English)

    ALWEENDO T E; SHIPEPE B T

    2008-01-01

    @@ Cotton has been identified as a crop with promising potential in Namibia.As such,cotton variety evaluation trials have been conducted for yield,fiber qualities,resistance to diseases and pests,as well as adaptability to the climatic conditions.

  6. Crystallization of calcium sulfate dihydrate under simulated conditions of phosphoric acid production in the presence of aluminum and magnesium ions

    Science.gov (United States)

    Rashad, M. M.; Mahmoud, M. H. H.; Ibrahim, I. A.; Abdel-Aal, E. A.

    2004-06-01

    The effect of Al 3+ and Mg 2+ ions, as additives, on the crystallization of gypsum was studied under simulated conditions of the phosphoric acid production. Calcium hydrogen phosphate and sulfuric acid were mixed with dilute phosphoric acid at 80°C, and the turbidity of the reaction mixture was measured at different time periods to calculate the induction time of gypsum crystals formation. Addition of Al 3+ ions up to 2% decreased the induction time and increased the growth efficiency while addition of Mg 2+ increased the induction time and decreased the growth efficiency compared with in absence of additives. Interestingly, the crystals mean and median diameters were found to increase in the presence of Al 3+ and decrease in the presence of Mg 2+. The surface energy increased with Al 3+ and decreased with Mg 2+ compared to the baseline (without additives). Gypsum morphology changed from needle-like type in absence of additives to thick-rhombic in the presence of Al 3+ ions.

  7. Unraveling the microscopic pathway of homogeneous water crystallization at supercooled conditions from direct simulations

    Science.gov (United States)

    Martelli, Fausto; Palmer, Jeremy; Singh, Rakesh; Debenedetti, Pablo; Car, Roberto

    By means of unbiased classical molecular dynamics simulations, we identify the microscopic pathways of spontaneous homogeneous crystallization in supercooled ST2 water. By introducing a new order parameter, we are able to monitor formation/disruption of locally ordered regions characterized by small ice clusters with intermediate range order. When two of these regions are close each other, they percolate and form a larger ordered region. The process is slow enough to allow for polymorphic selection in favor of cubic ice (Ic). The formation of an ice nucleus requires percolation of many small clusters so that the transformations at the interface of the nucleus do not involve its core, thus guaranteeing the stability of the nucleus. The growth of the crystalline nucleus is fast and involves direct transformation of interfacial liquid molecules as well as percolation of small Ic/Ih clusters. The growth is too fast to allow conversion of Ih into Ic sites, originating the formation of a stacking fault in the final crystal. We recognize Euclidean structures in the oxygen configuration of the second shell in Ic and Ih clusters. This new point of view allows us to explain the source of the ordered stacking fault geometry.

  8. Attitudes of young adults to prenatal screening and genetic correction for human attributes and psychiatric conditions.

    Science.gov (United States)

    Milner, K K; Collins, E E; Connors, G R; Petty, E M

    1998-03-05

    With recent advances in DNA technology, questions have arisen as to how this technology should be appropriately used. In this article, results obtained from a survey designed to elicit attitudes of college students to prenatal testing and gene therapy for human attributes and psychiatric conditions are reported. The eleven hypothetical disease phenotypes included schizophrenia, alcoholism, tendency toward violent behavior, attention deficit/hyperactivity disorder, depression requiring medical treatment, obesity, involvement in "dangerous" sports activities, homosexuality, borderline normal IQ (80-100), proportional short stature, and inability to detect perfect pitch. Most students supported prenatal genetic testing for psychiatric disorders and behavior that might result in harm to others (i.e., tendency towards violent behavior) and found prenatal genetic testing for human attributes less desirable. However, the lack of unilateral agreement or disagreement toward any one condition or attribute suggests the potential difficulties ahead in the quest for guidelines for the application of new technologies available to manipulate the human genome.

  9. Screening for Osmotic Stress Responses in Rice Varieties under Drought Condition

    Directory of Open Access Journals (Sweden)

    Simon Swapna

    2017-09-01

    Full Text Available Drought is the major abiotic stress factor that limits rice production worldwide. To evaluate the osmotic stress responses in rice varieties under drought condition, a total of 42 high-yielding rice varieties were collected from various research stations of Kerala Agricultural University in India. The experimental setup comprises of initial hydroponic treatments at different osmotic potentials, artificially induced by desired strengths of polyethylene glycol (PEG6000, and followed by the pot planted experiments in the rain-out-zone. The activities of antioxidant enzymes, relative water content, cell membrane stability, photosynthetic pigments, proline content, along with plant growth parameters of the varieties under drought condition were evaluated. Moreover, the standard scores of these rice varieties were assessed under stress and recovery conditions based on the scoring scale of the Standard Evaluation System for rice. Among the 42 rice varieties, we identified 2 rice varieties, Swarnaprabha and Kattamodan, with less leaf rolling, better drought recovery ability as well as relative water content, increased membrane stability index, osmolyte accumulation, and antioxidant enzyme activities pointed towards their degree of tolerance to drought stress. The positive adaptive responses of these rice varieties towards drought stress can be used in the genetic improvement of rice drought resistance breeding program.

  10. Mineral chemical compositions of late Cretaceous volcanic rocks in the Giresun area, NE Turkey: Implications for the crystallization conditions

    Science.gov (United States)

    Oǧuz, Simge; Aydin, Faruk; Uysal, İbrahim; Şen, Cüneyt

    2016-04-01

    This contribution contains phenocryst assemblages and mineral chemical data of late Cretaceous volcanic (LCV) rocks from the south of Görele and Tirebolu areas (Giresun, NE Turkey) in order to investigate their crystallization conditions. The LCV rocks in the study area occur in two different periods (Coniasiyen-Early Santonian and Early-Middle Campanian), which generally consist of alternation of mafic-intermediate (basaltic to andesitic) and felsic rock series (dacitic and rhyolitic) within each period. The basaltic and andesitic rocks in both periods generally exhibit porphyritic to hyalo-microlitic porphyritic texture, and contain phenocrysts of plagioclase and pyroxene, whereas the dacitic and rhyolitic rocks of the volcanic sequence usually show a vitrophyric texture with predominant plagioclase, K-feldspar, quartz and lesser amphibole-biotite phenocrysts. Zoned plagioclase crystals of the mafic and felsic rocks in different volcanic periods are basically different in composition. The compositions of plagioclase in the first-stage mafic rocks range from An52 to An78 whereas those of plagioclase from the first-stage felsic rocks have lower An content varying from An38 to An50. Rim to core profile for the zoned plagioclase of the first-stage mafic rocks show quite abrupt and notable compositional variations whereas that of the first-stage felsic rocks show slight compositional variation, although some of the grains may display reverse zoning. On the other hand, although no zoned plagioclase phenocryst observed in the second-stage mafic rocks, the compositions of microlitic plagioclase show wide range of compositional variation (An45-80). The compositions of zoned plagioclase in the second-stage felsic rocks are more calcic (An65-81) than those of the first-stage felsic rocks, and their rim to core profile display considerable oscillatory zoning. The compositions of pyroxenes in the first- and second-stage mafic-intermediate rocks vary over a wide range from

  11. Screening of Wild Strawberry Genotypes against Iron Deficiency under Greenhouse Conditions

    Directory of Open Access Journals (Sweden)

    Ayfer Alkan TORUN

    2013-12-01

    Full Text Available The cultivated strawberry Fragaria × ananassa Duch. is the natural hybrid of F. chiloensis (L. Mill. and F. virginiana Mill. The progenitor species have high genetic diversity compared with the cultivated genotypes; therefore, the use of wild relative in F. chiloensis breeding could provide a good for broadening the available genetic variations of cultivated species. In present study, 13 genotypes selected from strawberry super core collection were tested under Fe (- and Fe (+ conditions for their response against Fe deficiency conditions in a growth medium (GM (soil + sand + perlite, potentially able to simulate the actual GM in nature. SPAD-meter readings indicating chlorophyll levels of the leaf, shoot dry matter yield, Fe-efficiency rate, shoot total and active Fe concentrations were determined to evaluate the resistance levels of strawberry genotypes against Fe deficiency. Results of this study indicated that different response for strawberry subspecies and genotypes of the same subspecies grown in GM against Fe deficiency. Symptom for Fe deficiency of genotypes varied between 1-5, SPAD-meter readings 3, shoot dry matter yields and shoot Fe concentrations varied between 6.5-38, 1.02-6.06 g plant-1 and 41.8-233.1 mg kg-1 respectively. Iron-efficiencies of genotypes were found between 58–98%. Strawberry subspecies, F. virginiana spp. glauca, F. chiloensis ssp. chiloensis and F. chiloensis ssp. pacifica showed Fe-efficiency values of 93.8, 79.5 and 79.1% respectively. We concluded that shoot growth performance, Fe intake from GM, transfer of Fe from roots to shoots, shoot Fe-use efficiency, Fe deficiency symptom levels and SPAD-meter readings indicating chlorophyll levels were significant parameters to evaluate the resistance of strawberry genotypes against Fe deficiency. The most Fe-efficient genotypes belonging to F. virginiana spp. glauca could be used in breeding programs aiming at developing new strawberry genotypes suitable for

  12. Purified human pancreatic duct cell culture conditions defined by serum-free high-content growth factor screening.

    Directory of Open Access Journals (Sweden)

    Corinne A Hoesli

    Full Text Available The proliferation of pancreatic duct-like CK19+ cells has implications for multiple disease states including pancreatic cancer and diabetes mellitus. The in vitro study of this important cell type has been hampered by their limited expansion compared to fibroblast-like vimentin+ cells that overgrow primary cultures. We aimed to develop a screening platform for duct cell mitogens after depletion of the vimentin+ population. The CD90 cell surface marker was used to remove the vimentin+ cells from islet-depleted human pancreas cell cultures by magnetic-activated cell sorting. Cell sorting decreased CD90+ cell contamination of the cultures from 34±20% to 1.3±0.6%, yielding purified CK19+ cultures with epithelial morphology. A full-factorial experimental design was then applied to test the mitogenic effects of bFGF, EGF, HGF, KGF and VEGF. After 6 days in test conditions, the cells were labelled with BrdU, stained and analyzed by high-throughput imaging. This screening assay confirmed the expected mitogenic effects of bFGF, EGF, HGF and KGF on CK19+ cells and additionally revealed interactions between these factors and VEGF. A serum-free medium containing bFGF, EGF, HGF and KGF led to CK19+ cell expansion comparable to the addition of 10% serum. The methods developed in this work should advance pancreatic cancer and diabetes research by providing effective cell culture and high-throughput screening platforms to study purified primary pancreatic CK19+ cells.

  13. Sufficient condition for the existence of interface states in some two-dimensional photonic crystals

    Science.gov (United States)

    Huang, Xueqin; Xiao, Meng; Zhang, Zhao-Qing; Chan, C. T.

    2014-08-01

    There is no assurance that interface states can be found at the boundary separating two materials. While a strong perturbation typically favors wave localization, we show on the contrary that in some two-dimensional photonic crystals (PCs) possessing a Dirac-like cone at k = 0 derived from monopole and dipoles excitation, a small perturbation is sufficient to create interface states. The conical dispersion together with the flat band at the zone center generates the existence of gaps in the projected band structure and the existence of single mode interface states inside the projected band gaps stems from the geometric phases of the bulk bands. The underlying physics for the existence of an interface state is related to the sign change of the surface impedance in the gaps above and below the flat band. The established results are applicable for long wavelength regimes where there is only one propagating diffraction order for an interlayer scattering.

  14. Study of polycrystalline silicon obtained by aluminum-induced crystallization depending on process conditions

    Science.gov (United States)

    Pereyaslavtsev, Alexander; Sokolov, Igor; Sinev, Leonid

    2016-11-01

    In this paper, we have decided to consider an alternative method of producing polycrystalline silicon and study change of its electrophysical characteristics depending on process parameters. As an alternative low-pressure chemical vapor deposition method appears aluminum-induced crystallization (AIC), which allows to obtain a polycrystalline silicon film is significantly larger grain size, thereby reducing contribution of grain boundaries. A comprehensive study of polycrystalline silicon was carried out using a variety of microscopic (OM, SEM) and spectroscopic (RAMAN, XPS) and diffraction (EBSD, XRD) analytic methods. We also considered possibility of self-doping in AIC, result of which was obtained polycrystalline silicon with different resistance. Additionally considered changes in temperature coefficient of resistance depending on technological parameters of AIC process.

  15. A new on-line luminometer and beam conditions monitor using single crystal diamond sensors

    CERN Document Server

    CMS Collaboration

    2015-01-01

    Instrumentation near the beam-pipe requires extremely radiation hard sensors. Inside CMS two rings instrumented with 12 single crystal diamond sensors each are installed on both sides of the interaction point. The sensors are subdivided in two pads, and each pad is read out by a dedicated fast radiation hard ASIC in 130 nm CMOS technology. Due to the excellent time resolution collision products will be separated from machine induced background. In the backend a dead-time less histogramming unit is used, and a fast microTCA system with GHz sampling rate is under development. The detector will measure both the on-line luminosity and the background bunch-by-bunch. The performance of a prototype detector in a test-beam will be reported, and results from the operation during data taking will be presented.

  16. A new on-line luminometer and beam conditions monitor using single crystal diamond sensors

    CERN Document Server

    Karacheban, Olena

    2015-01-01

    Instrumentation near the beam-pipe requires extremely radiation hardsensors. Inside CMS two rings instrumented with 12 single crystal diamondsensors each are installed on both sides of the interaction point. Thesensors are subdivided in two pads, and each pad is read out by adedicated fast radiation hard ASIC in 130 nm CMOS technology.Due to the excellent time resolution collision products will be separatedfrom machine induced background. In the backend a dead-time lesshistogramming unit is udsed, and a fast microTCA system with GHz samplingrate is under development.The detector will measure both the on-line luminosity and the backgroundbunch-by-bunch.The performance of a prototype detector in a test-beam will be reported,and results from the operation during data taking will be presented.

  17. Systematic microcarrier screening and agitated culture conditions improves human mesenchymal stem cell yield in bioreactors.

    Science.gov (United States)

    Rafiq, Qasim A; Coopman, Karen; Nienow, Alvin W; Hewitt, Christopher J

    2016-03-01

    Production of human mesenchymal stem cells for allogeneic cell therapies requires scalable, cost-effective manufacturing processes. Microcarriers enable the culture of anchorage-dependent cells in stirred-tank bioreactors. However, no robust, transferable methodology for microcarrier selection exists, with studies providing little or no reason explaining why a microcarrier was employed. We systematically evaluated 13 microcarriers for human bone marrow-derived MSC (hBM-MSCs) expansion from three donors to establish a reproducible and transferable methodology for microcarrier selection. Monolayer studies demonstrated input cell line variability with respect to growth kinetics and metabolite flux. HBM-MSC1 underwent more cumulative population doublings over three passages in comparison to hBM-MSC2 and hBM-MSC3. In 100 mL spinner flasks, agitated conditions were significantly better than static conditions, irrespective of donor, and relative microcarrier performance was identical where the same microcarriers outperformed others with respect to growth kinetics and metabolite flux. Relative growth kinetics between donor cells on the microcarriers were the same as the monolayer study. Plastic microcarriers were selected as the optimal microcarrier for hBM-MSC expansion. HBM-MSCs were successfully harvested and characterised, demonstrating hBM-MSC immunophenotype and differentiation capacity. This approach provides a systematic method for microcarrier selection, and the findings identify potentially significant bioprocessing implications for microcarrier-based allogeneic cell therapy manufacture.

  18. Two-stage crystallization of charged colloids under low supersaturation conditions.

    Science.gov (United States)

    Kratzer, Kai; Arnold, Axel

    2015-03-21

    We report simulations on the homogeneous liquid-fcc nucleation of charged colloids for both low and high contact energy values. As a precursor for crystal formation, we observe increased local order at the position where the crystal will form, but no correlations with the local density. Thus, the nucleation is driven by order fluctuations rather than density fluctuations. Our results also show that the transition involves two stages in both cases, first a transition of liquid → bcc, followed by a bcc → hcp/fcc transition. Both transitions have to overcome free energy barriers, so that a spherical bcc-like cluster is formed first, in which the final fcc structure is nucleated mainly at the surface of the crystallite. This means that the second stage bcc-fcc phase transition is a heterogeneous nucleation in the partially grown solid phase, even though we start from a homogeneous bulk liquid. The height of the bcc → hcp/fcc free energy barrier strongly depends on the contact energies of the colloids. For low contact energy this barrier is low, so that the bcc → hcp/fcc transition occurs spontaneously. For the higher contact energy, the second barrier is too high to be crossed spontaneously by the colloidal system. However, it was possible to ratchet the system over the second barrier and to transform the bcc nuclei into the stable hcp/fcc phase. The transitions are dominated by the first liquid-bcc transition and can be described by classical nucleation theory using an effective surface tension.

  19. Health surveillance under adverse ergonomics conditions--validity of a screening method adapted for the occupational health service.

    Science.gov (United States)

    Jonker, Dirk; Gustafsson, Ewa; Rolander, Bo; Arvidsson, Inger; Nordander, Catarina

    2015-01-01

    A new health surveillance protocol for work-related upper-extremity musculoskeletal disorders has been validated by comparing the results with a reference protocol. The studied protocol, Health Surveillance in Adverse Ergonomics Conditions (HECO), is a new version of the reference protocol modified for application in the Occupational Health Service (OHS). The HECO protocol contains both a screening part and a diagnosing part. Sixty-three employees were examined. The screening in HECO did not miss any diagnosis found when using the reference protocol, but in comparison to the reference protocol considerable time savings could be achieved. Fair to good agreement between the protocols was obtained for one or more diagnoses in neck/shoulders (86%, k = 0.62) and elbow/hands (84%, k = 0.49). Therefore, the results obtained using the HECO protocol can be compared with a reference material collected with the reference protocol, and thus provide information of the magnitude of disorders in an examined work group. Practitioner Summary: The HECO protocol is a relatively simple physical examination protocol for identification of musculoskeletal disorders in the neck and upper extremities. The protocol is a reliable and cost-effective tool for the OHS to use for occupational health surveillance in order to detect workplaces at high risk for developing musculoskeletal disorders.

  20. Screening for drought tolerance: comparison of maize hybrids under water deficit condition

    Directory of Open Access Journals (Sweden)

    Qurban Ali

    2016-02-01

    Full Text Available Background: Maize is an important cereal crop, grown throughout the globe for human food and livestock feed, but biotic and abiotic factors had shown adverse effects on biomass and grain yield. Changing climatic conditions have imposed drought (water scarcity as a major problem to combat with yield losses and biomass in maize and other cereals. Methods: The prescribed study was conducted to evaluate F1 hybrids at seedling subject to 45% moisture level. The data was recorded and subjected to multivariate analysis to find the significant variation attributed by various traits under stress conditions for efficient root/shoot development. Results: Significant differences were found in F1 hybrids for all studied traits. Higher heritability was found for root length, shoot length and fresh shoot weight, while fresh shoot weight, dry shoot weight and dry root weight showed higher genetic advance. Significant correlation was found for dry root weight to fresh shoot length and fresh root length, fresh root weight to fresh root/shoot weight ratio and fresh shoot weight. The hybrids Sh-139×B-316, Raka-poshi×B-316, B-327×B-316, Sh-139×EV-340, EV-1097Q×EV-347, EV-1097Q×EV-340, EV-1097Q×Pop/209 and B-327×EV-340 showed higher and positive heterosis and heterobeltiosis for most of the studied traits. To assess the overall variation on dependent structure, we used multivariate analysis, an important tool in breeding program, for efficient selection. Conclusions: EV-1097Q×Pop/209 and Sh-139×EV-340 showed significant results for root and shoot development under various water stress regimes at seedling stage, thus further studies should be carried out to find out the known and un-known loci regarding root and shoot development traits in high yielding maize cultivars under arid/semi-arid regions.

  1. Optimization of buffer solutions for protein crystallization.

    Science.gov (United States)

    Gosavi, Rajendrakumar A; Mueser, Timothy C; Schall, Constance A

    2008-05-01

    Increasing the solubility of protein stock solutions to above that in a standard chromatography buffer (50 mM Tris-HCl pH 7.5, 100 mM NaCl) led to an increase in the number of crystallization conditions for ten globular proteins subjected to two crystal screens: the Index and Precipitant/Precipitant-Additive (P/PA) Screens. Solubility enhancement of protein stock solutions was achieved through screening and selection of buffer components to formulate an optimal buffer. Relative improvements in solubility were estimated through protection against the precipitation of protein by polyethylene glycol 8000. Proteins with limited solubility improvement in optimal buffer showed an enhancement in solubility on addition of glycerol. Maximum solubility was then determined by the concentration of optimized solutions until precipitate formed. The supernatant concentration then provided an estimate of the upper limit of protein solubility. This 'solubility' estimate is used to specify the initial concentration of the protein used in the screening experiments and is an important step in successful crystallization. Buffer optimization and establishment of initial protein concentration for crystal screening based on solubility estimates provides a methodology for improved crystal screening results.

  2. High throughput nanostructure-initiator mass spectrometry screening of microbial growth conditions for maximal β-glucosidase production

    Directory of Open Access Journals (Sweden)

    Xiaoliang eCheng

    2013-12-01

    Full Text Available Production of biofuels via enzymatic hydrolysis of complex plant polysaccharides is a subject of intense global interest. Microbial communities are known to express a wide range of enzymes necessary for the saccharification of lignocellulosic feedstocks and serve as a powerful reservoir for enzyme discovery. However, the growth temperature and conditions that yield high cellulase activity vary widely, and the throughput to identify optimal conditions has been limited by the slow handling and conventional analysis. A rapid method that uses small volumes of isolate culture to resolve specific enzyme activity is needed. In this work, a high throughput nanostructure-initiator mass spectrometry (NIMS based approach was developed for screening a thermophilic cellulolytic actinomycete, Thermobispora bispora, for β-glucosidase production under various growth conditions. Media that produced high β-glucosidase activity were found to be I/S + glucose or microcrystalline cellulose (MCC, Medium 84 + rolled oats, and M9TE + MCC at 45 °C. Supernatants of cell cultures grown in M9TE + 1% MCC cleaved 2.5 times more substrate at 45 °C than at all other temperatures. While T. bispora is reported to grow optimally at 60 °C in Medium 84 + rolled oats and M9TE + 1% MCC, approximately 40% more conversion was observed at 45 °C. This high throughput NIMS approach may provide an important tool in discovery and characterization of enzymes from environmental microbes for industrial and biofuel applications.

  3. Computational crystallization.

    Science.gov (United States)

    Altan, Irem; Charbonneau, Patrick; Snell, Edward H

    2016-07-15

    Crystallization is a key step in macromolecular structure determination by crystallography. While a robust theoretical treatment of the process is available, due to the complexity of the system, the experimental process is still largely one of trial and error. In this article, efforts in the field are discussed together with a theoretical underpinning using a solubility phase diagram. Prior knowledge has been used to develop tools that computationally predict the crystallization outcome and define mutational approaches that enhance the likelihood of crystallization. For the most part these tools are based on binary outcomes (crystal or no crystal), and the full information contained in an assembly of crystallization screening experiments is lost. The potential of this additional information is illustrated by examples where new biological knowledge can be obtained and where a target can be sub-categorized to predict which class of reagents provides the crystallization driving force. Computational analysis of crystallization requires complete and correctly formatted data. While massive crystallization screening efforts are under way, the data available from many of these studies are sparse. The potential for this data and the steps needed to realize this potential are discussed.

  4. Influence of crystallization conditions on the tensile properties of radiation crosslinked, vitamin E stabilized UHMWPE.

    Science.gov (United States)

    George, A; Ngo, H D; Bellare, A

    2014-12-01

    Radiation crosslinking for ultra-high molecular weight polyethylene results in improved wear resistance but a reduction in mechanical properties. Incorporation of vitamin E has been known to decrease the rate of oxidative degradation occurring through radiation crosslinking and prevents the need for post-irradiation melting with subsequent loss of crystallinity. In this study, we aimed to determine the effect of thermal treatments prior to crosslinking on the morphology and tensile properties of vitamin-E-containing polyethylene. Vitamin-E-blended polyethylene was melted and subsequently quenched in ice water in order to induce high rate crystallization. A second group was additionally annealed at 126°C following quenching and all samples were irradiated using electron beam radiation to a dose of 100kGy. The morphology of control, quenched and quench-annealed polyethylene was characterized using small angle x-ray scattering and differential scanning calorimetry. Tensile properties of these polyethylenes were measured before and after radiation crosslinking with equilibrium swelling experiments performed to assess the crosslink density of irradiated samples. This study shows how the tensile properties of polyethylene can be enhanced by varying thermal treatments prior to crosslinking; and thus how it may be possible to offset the reduction in tensile properties afforded by the crosslinking process.

  5. The effect of environmental conditions on designing of a photonic crystal force sensor

    Science.gov (United States)

    Li, Longqiu; Li, Tianlong; Song, Wenping; Zhang, Guangyu; Li, Yao

    2014-03-01

    Microcantilever sensors have been widely used in designing force, strain and biochemical sensors. The fast-growing applications in nanoelectromechanical systems (NEMS) lead to strong demands to downsize the sensing elements to nanometer scale. In this paper, the detected environment on the performance of this photonic crystal sensor is investigated. The nanocavity, which can be used to localize the electromagnetic field in a low refractive index region, is a new sensing method to measure nano-scaled deformation. Through numerical simulation, we demonstrate that the range of the force sensor in each component force in X and Y directions are 0-1μN. In X direction, the minimum detectable applied forces are about 0.057μN and 0.070μN for the microcantilever operated in the water and air, respectively. And these in Y direction are 0.043μN and 0.053μN, respectively. Hence, it shows that a better resolution of applied force can be achieved in water than in air.

  6. Elasticity of single-crystal superhydrous phase B at simultaneous high pressure-temperature conditions

    Science.gov (United States)

    Li, Xinyang; Mao, Zhu; Sun, Ningyu; Liao, Yifan; Zhai, Shuangmeng; Wang, Yi; Ni, Huaiwei; Wang, Jingyun; Tkachev, Sergey N.; Lin, Jung-Fu

    2016-08-01

    We investigated the combined effect of pressure and temperature on the elasticity of single-crystal superhydrous phase B (Shy-B) using Brillouin scattering and X-ray diffraction up to 12 GPa and 700 K. Using the obtained elasticity, we modeled the anisotropy of Shy-B along slab geotherms, showing that Shy-B has a low anisotropy and cannot be the major cause of the observed anisotropy in the region. Modeled velocities of Shy-B show that Shy-B will be shown as positive velocity anomalies at the bottom transition zone. Once Shy-B is transported to the topmost lower mantle, it will exhibit a seismic signature of lower velocities than topmost lower mantle. We speculate that an accumulation of hydrous phases, such as Shy-B, at the topmost lower mantle with a weight percentage of ~17-26% in the peridotite layer as subduction progresses could help explain the observed 2-3% low shear velocity anomalies in the region.

  7. The contribution of polystyrene nanospheres towards the crystallization of proteins.

    Directory of Open Access Journals (Sweden)

    Johanna M Kallio

    Full Text Available BACKGROUND: Protein crystallization is a slow process of trial and error and limits the amount of solved protein structures. Search of a universal heterogeneous nucleant is an effort to facilitate crystallizability of proteins. METHODOLOGY: The effect of polystyrene nanospheres on protein crystallization were tested with three commercial proteins: lysozyme, xylanase, xylose isomerase, and with five research target proteins: hydrophobins HFBI and HFBII, laccase, sarcosine dimethylglycine N-methyltransferase (SDMT, and anti-testosterone Fab fragment 5F2. The use of nanospheres both in screening and as an additive for known crystallization conditions was studied. In screening, the addition of an aqueous solution of nanosphere to the crystallization drop had a significant positive effect on crystallization success in comparison to the control screen. As an additive in hydrophobin crystallization, the nanospheres altered the crystal packing, most likely due to the amphiphilic nature of hydrophobins. In the case of laccase, nanospheres could be used as an alternative for streak-seeding, which insofar had remained the only technique to produce high-diffracting crystals. With methyltransferase SDMT the nanospheres, used also as an additive, produced fewer, larger crystals in less time. Nanospheres, combined with the streak-seeding method, produced single 5F2 Fab crystals in shorter equilibration times. CONCLUSIONS: All in all, the use of nanospheres in protein crystallization proved to be beneficial, both when screening new crystallization conditions to promote nucleation and when used as an additive to produce better quality crystals, faster. The polystyrene nanospheres are easy to use, commercially available and close to being inert, as even with amphiphilic proteins only the crystal packing is altered and the nanospheres do not interfere with the structure and function of the protein.

  8. Automatic classification and pattern discovery in high-throughput protein crystallization trials.

    Science.gov (United States)

    Cumbaa, Christian; Jurisica, Igor

    2005-01-01

    Conceptually, protein crystallization can be divided into two phases search and optimization. Robotic protein crystallization screening can speed up the search phase, and has a potential to increase process quality. Automated image classification helps to increase throughput and consistently generate objective results. Although the classification accuracy can always be improved, our image analysis system can classify images from 1,536-well plates with high classification accuracy (85%) and ROC score (0.87), as evaluated on 127 human-classified protein screens containing 5,600 crystal images and 189,472 non-crystal images. Data mining can integrate results from high-throughput screens with information about crystallizing conditions, intrinsic protein properties, and results from crystallization optimization. We apply association mining, a data mining approach that identifies frequently occurring patterns among variables and their values. This approach segregates proteins into groups based on how they react in a broad range of conditions, and clusters cocktails to reflect their potential to achieve crystallization. These results may lead to crystallization screen optimization, and reveal associations between protein properties and crystallization conditions. We also postulate that past experience may lead us to the identification of initial conditions favorable to crystallization for novel proteins.

  9. Effect of heating conditions on flow patterns during the seeding stage of Kyropoulos sapphire crystal growth

    Science.gov (United States)

    Timofeev, Vladimir V.; Kalaev, Vladimir V.; Ivanov, Vadim G.

    2016-07-01

    We apply numerical simulation to understand the effect of heating conditions on melt convection in an industrial Ky furnace. The direct numerical simulation (DNS) approach was used to investigate the features of melt flow during the seeding stage. Two different cases of Kyropoulos furnace hot zone design were studied numerically, and results were compared with experimental data to understand the effect of modifications on melt convection.

  10. Hückel and möbius boundary conditions for solids and orbital symmmetry correlation in the rotational phase transition of molecular crystals

    Science.gov (United States)

    Chiu, Ying-Nan

    1983-05-01

    A new cyclic boundary condition which corresponds to a Möbius strip representation of a one-dimensional crystal is introduced. It is compared with the usual Bloch and Born—von Karman boundary condition which is shown to be a Hückel condition in the sense of LCAO MO treatment of a ring structure. The potential relevance of this Möbius condition to one-dimensional molecular and liquid crystals in which the relative molecular orientation changes during phase transition is alluded to. A comparison of the energies for the twisted and non-twisted form of the linear crystal is derived in the LCAO approximation. The orbital symmetry correlation in the concerted twist of the atomic or molecular orbitals atom! the linear backbone during a rotational polymorphic structural transition is also derived.

  11. SEMICONDUCTOR MATERIALS: Chemical etching of a GaSb crystal incorporated with Mn grown by the Bridgman method under microgravity conditions

    Science.gov (United States)

    Xiaofeng, Chen; Nuofu, Chen; Jinliang, Wu; Xiulan, Zhang; Chunlin, Chai; Yude, Yu

    2009-08-01

    A GaSb crystal incorporated with Mn has been grown by the Bridgman method on the Polizon facility onboard the FOTON-M3 spacecraft. Structural defects and growth striations have been successfully revealed by the chemical etching method. By calculating various parameters of the convection, the striation patterns can be explained, and the critical value of the Taylor number, which characterizes the convective condition of the rotating magnetic field induced azimuthal flow, was shown. The stresses generated during crystal growth can be reflected by the observations of etch pit distribution and other structural defects. Suggestions for improving the space experiment to improve the quality of the crystal are given.

  12. Effects of milling and crystallization conditions on microstructure of Nd2Fe14B/α-Fe powder

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; WANG Er-de

    2007-01-01

    Effects of milling and crystallization conditions on microstructure, such as amorphous phase and nanocrystalline phase, were investigated by X-ray diffractometry(XRD), differential scanning calorimetry(DSC), and transmission electron microscopy (TEM), respectively. The results show that nanocomposite Nd2Fe14B/α-Fe powder can be prepared by mechanical milling in argon atmosphere and a subsequent vacuum annealing treatment. The grain sizes of both Nd2Fe14B and α-Fe phase decrease drastically with increasing milling time. After milling for 5 h, the as-milled material consists of α-Fe nanocomposite phases with the grain size of 10 nm, and some amorphous phases, which can be turned into Nd2Fe14B/α-Fe nanocomposite phases by the subsequent annealing treatment. Milling energy of mechanical milling after 5 h by theoretical calculation is 6 154.25 kJ/g.

  13. Chemical etching of a GaSb crystal incorporated with Mn grown by the Bridgman method under microgravity conditions

    Institute of Scientific and Technical Information of China (English)

    Chen Xiaofeng; Chen Nuofu; Wu Jinliang; Zhang Xiulan; Chai Chunlin; Yu Yude

    2009-01-01

    uring crystal growth can be reflected by the observations of etch pit distribution and other structural defects. Suggestions for improving the space experiment to improve the quality of the crystal are given.

  14. Influence of Growth Conditions on Magnetite Nanoparticles Electro-Crystallized in the Presence of Organic Molecules

    Directory of Open Access Journals (Sweden)

    Saba Mosivand

    2013-05-01

    Full Text Available Magnetite nanoparticles were synthesized by electrocrystallization in the presence of thiourea or sodium butanoate as an organic stabilizer. The synthesis was performed in a thermostatic electrochemical cell containing two iron electrodes with an aqueous solution of sodium sulfate as electrolyte. The effects of organic concentration, applied potential and growth temperature on particle size, morphology, structure and magnetic properties were investigated. The magnetite nanoparticles were characterized by X-ray diffraction, electron microscopy, magnetometry and Mössbauer spectrometry. When the synthesis is performed in the presence of sodium butanoate at 60 °C, a paramagnetic ferric salt is obtained as a second phase; it is possible to avoid formation of this phase, increase the specific magnetization and improve the structure of the oxide particles by tuning the growth conditions. Room-temperature magnetization values range from 45 to 90 Am2kg−1, depending on the particle size, type of surfactant and synthesis conditions. Mössbauer spectra, which were recorded at 290 K for all the samples, are typical of nonstoichiometric Fe3−δO4, with a small excess of Fe3+, 0.05 ≤ δ ≤ 0.15.

  15. Influence of growth conditions on magnetite nanoparticles electro-crystallized in the presence of organic molecules.

    Science.gov (United States)

    Mosivand, Saba; Monzon, Lorena M A; Kazeminezhad, Iraj; Coey, J Michael D

    2013-05-17

    Magnetite nanoparticles were synthesized by electrocrystallization in the presence of thiourea or sodium butanoate as an organic stabilizer. The synthesis was performed in a thermostatic electrochemical cell containing two iron electrodes with an aqueous solution of sodium sulfate as electrolyte. The effects of organic concentration, applied potential and growth temperature on particle size, morphology, structure and magnetic properties were investigated. The magnetite nanoparticles were characterized by X-ray diffraction, electron microscopy, magnetometry and Mössbauer spectrometry. When the synthesis is performed in the presence of sodium butanoate at 60 °C, a paramagnetic ferric salt is obtained as a second phase; it is possible to avoid formation of this phase, increase the specific magnetization and improve the structure of the oxide particles by tuning the growth conditions. Room-temperature magnetization values range from 45 to 90 Am2kg-1, depending on the particle size, type of surfactant and synthesis conditions. Mössbauer spectra, which were recorded at 290 K for all the samples, are typical of nonstoichiometric Fe3-δO4, with a small excess of Fe3+, 0.05 ≤ δ ≤ 0.15.

  16. Scintillating screens for micro-imaging based on the Ce-Tb doped LuAP single crystal films

    OpenAIRE

    Douissard, Paul-Antoine; MARTIN, Thierry; Riva, Federica; Mathieu, Eric; Zorenko, Yuriy; Savchyn, Volodymyr; Zorenko, Tetyana; Fedorov, Alexander

    2014-01-01

    Single Crystal Film (SCF) scintillators are key-components of today's high-resolution 2D X-ray detectors used at synchrotrons for applications such as X-ray Radiography, Computed Tomography (CT), laminography, full-field XANES, and topography. Due to its high density and effective atomic number, LuAlO3 (LuAP) perovskite has a great potential to replace or complement the currently used Eu-doped Gd3Ga5O12 (GGG:Eu) and Tb-doped Lu2SiO5 (LSO:Tb) SCFs. In this article we present the growth of LuAP...

  17. Luminescence decay of PbWO sub 4 crystals under different excitation conditions

    CERN Document Server

    Itoh, M; Fujita, M

    2003-01-01

    This paper reports the decay kinetics of the intrinsic blue luminescence from self-trapped excitons in lead tungstate excited by a Nd:YAG laser. The kinetics exhibits some complicated features, depending strongly on the experimental conditions, such as laser power, sample temperature, and one- or two-photon excitation. The result indicates that the self-trapped excitons interact with each other under high-density excitation, thereby shortening the decay time of the blue luminescence. Furthermore, a noticeable rise component is observed under two-photon excitation in the temperature range of 50-150 K. The contribution of radiation-induced defect centres in the process of energy transfer from Pb sites to WO sub 4 sites is discussed.

  18. Lipid phase behavior studied with a quartz crystal microbalance: A technique for biophysical studies with applications in screening

    Science.gov (United States)

    Peschel, Astrid; Langhoff, Arne; Uhl, Eva; Dathathreyan, Aruna; Haindl, Susanne; Johannsmann, Diethelm; Reviakine, Ilya

    2016-11-01

    Quartz crystal microbalance (QCM) is emerging as a versatile tool for studying lipid phase behavior. The technique is attractive for fundamental biophysical studies as well applications because of its simplicity, flexibility, and ability to work with very small amounts of material crucial for biomedical studies. Further progress hinges on the understanding of the mechanism, by which a surface-acoustic technique such as QCM, senses lipid phase changes. Here, we use a custom-built instrument with improved sensitivity to investigate phase behavior in solid-supported lipid systems of different geometries (adsorbed liposomes and bilayers). We show that we can detect a model anesthetic (ethanol) through its effect on the lipid phase behavior. Further, through the analysis of the overtone dependence of the phase transition parameters, we show that hydrodynamic effects are important in the case of adsorbed liposomes, and viscoelasticity is significant in supported bilayers, while layer thickness changes make up the strongest contribution in both systems.

  19. Nanosuspension for improving the bioavailability of a poorly soluble drug and screening of stabilizing agents to inhibit crystal growth.

    Science.gov (United States)

    Ghosh, Indrajit; Bose, Sonali; Vippagunta, Radha; Harmon, Ferris

    2011-05-16

    The purpose of this study was to develop a nanosuspension of a poorly soluble drug by nanomilling process using wet media milling to achieve superior in vitro dissolution and high in vivo exposure in pharmacokinetic studies. A promising nanosuspension was developed with Vitamin E TPGS based formulation with particle size in the nano range. Although the formulation showed significant improvement during in vitro dissolution and in vivo plasma level, probably due to the strong hydrophobic interaction between Vitamin TPGS and the drug molecule, crystal growth was observed during stability studies. A systematic study was done with different combinations of solubilizer/stabilizer system in order to obtain a more stable nanosuspension. Hydroxypropyl methylcellulose (HPMC 3 cps) was found to stabilize the nanosuspension by better surface coverage due to stronger interaction with the drug as compared to other stabilizers used in this study.

  20. Mineral Chemistry and Crystallization Conditions of the Late Cretaceous Mamba Pluton from the Eastern Gangdese, Southern Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    Xiaowei Li; Xuanxue Mo; Mark Scheltens; Qi Guan

    2016-01-01

    The Late Cretaceous Mamba granodiorite belongs to a part of the Mesozoic Gangdese con-tinental magmatic belt. No quantitative mineralogical study has been made hitherto, and hence the depth at which it formed is poorly constrained. Here we present mineralogical data for the Mamba pluton, in-cluding host rocks and their mafic microgranular enclaves (MMEs), to provide insights into their overall crystallization conditions and information about magma mixing. All amphiboles in the Mamba pluton are calcic, withB(Ca+Na)>1.5, and Si=6.81–7.42 apfu for the host rocks and Si=6.77–7.35 apfu for the MMEs. The paramount cation substitutions in amphibole include edenite type and tschermakite type. Biotites both in the host rocks and the MMEs collectively have high MgO (13.19 wt.%–13.03 wt.%) contents, but define a narrow range of Al apfu (atoms per formula unit) variations (2.44–2.57). The oxygen fugacity es-timates are based on the biotite compositions cluster around the NNO buffer. The calculated pressure ranges from 1.2 to 2.1 kbar according to the aluminum-in-hornblende barometer. The computed pressure varies from 0.9 to 1.3 kbar based on the aluminum-in-biotite barometer which corresponds to an average depth of ca. 3.9 km. Besides, the estimates of crystallization pressures vary from 0.8 to 1.4 kbar based on the amphibole barometer proposed by Ridolfi et al. (2010), which can be equivalent to the depths ranging from 3.1 to 5.2 km. The MMEs have plagioclase oscillatory zonings and quartz aggregates, probably indi-cating the presence of magma mixing. Besides, core-to-rim element variations (Rb, Sr, Ba, and P) for the K-feldspar megacrysts serve as robust evidence to support magma mixing and crystal fractionation. This indicates the significance of the magma mixing that contributes to the formation of K-feldspar megacryst zonings in the Mamba pluton.

  1. Crystal Structure of Calcium Silicate Perovskite Synthesized under Water Saturated Conditions at Mantle Related Pressure-Temperature

    Science.gov (United States)

    Chen, H.; Shim, S. H. D.; Leinenweber, K. D.; Meng, Y.; Prakapenka, V.

    2014-12-01

    Perovskite-structured CaSiO3 (Ca-Pv) is the third most abundant mineral in the lower mantle. However, its crystal structure is still under debate and the solubility of H2O in Ca-Pv is not well constrained. We have conducted in situ X-ray diffraction measurements on Ca-Pv under H2O saturated conditions in the laser-heated diamond-anvil cell at the GSECARS and HPCAT sectors of the Advanced Photon Source. Glass starting materials were mixed with platinum powder (10 wt%) for laser coupling and internal pressure scale. Cold compressed foils of the mixtures were loaded in the diamond-anvil cell together with Ne or water. The X-ray diffraction patterns of the Ca-Pv sample synthesized in a Ne medium are consistent with a cubic perovskite structure at both 300 K and high temperatures up to 2,400 K at 50 GPa. No clear peak splittings were observed within the resolution of the angle-dispersive powder diffraction technique. However, in the experiments with water, clear splitting of the 200 diffraction line appears during heating to temperatures over 2000 K and remain after temperature quench at 32 GPa. The peak splittings were clearly observed at high temperatures to 2400 K, which is close to the melting point of water at the pressure. The different structural behaviors of Ca-Pv depending on media (Ne and water) may suggest that OH might enter into the crystal structure of nominally anhydrous Ca-Pv phase at high pressure and high temperature.

  2. 42 CFR 410.19 - Ultrasound screening for abdominal aortic aneurysms: Condition for and limitation on coverage.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Ultrasound screening for abdominal aortic aneurysms... screening for an abdominal aortic aneurysm as a result of an initial preventive physical examination (as... for an abdominal aortic aneurysm under Medicare program; and (3) Is included in at least one of...

  3. Screening and in situ synthesis using crystals of a NAD kinase lead to a potent antistaphylococcal compound.

    Science.gov (United States)

    Gelin, Muriel; Poncet-Montange, Guillaume; Assairi, Liliane; Morellato, Laurence; Huteau, Valérie; Dugué, Laurence; Dussurget, Olivier; Pochet, Sylvie; Labesse, Gilles

    2012-06-06

    Making new ligands for a given protein by in situ ligation of building blocks (or fragments) is an attractive method. However, it suffers from inherent limitations, such as the limited number of available chemical reactions and the low information content of usual chemical library deconvolution. Here, we describe a focused screening of adenosine derivatives using X-ray crystallography. We discovered an unexpected and biocompatible chemical reactivity and have simultaneously identified the mode of binding of the resulting products. We observed that the NAD kinase from Listeria monocytogenes (LmNADK1) can promote amide formation between 5'-amino-5'-deoxyadenosine and carboxylic acid groups. This unexpected reactivity allowed us to bridge in situ two adenosine derivatives to fully occupy the active NAD site. This guided the design of a close analog showing micromolar inhibition of two human pathogenic NAD kinases and potent bactericidal activity against Staphylococcus aureus in vitro.

  4. Statistical analysis of crystallization database links protein physico-chemical features with crystallization mechanisms.

    Directory of Open Access Journals (Sweden)

    Diana Fusco

    Full Text Available X-ray crystallography is the predominant method for obtaining atomic-scale information about biological macromolecules. Despite the success of the technique, obtaining well diffracting crystals still critically limits going from protein to structure. In practice, the crystallization process proceeds through knowledge-informed empiricism. Better physico-chemical understanding remains elusive because of the large number of variables involved, hence little guidance is available to systematically identify solution conditions that promote crystallization. To help determine relationships between macromolecular properties and their crystallization propensity, we have trained statistical models on samples for 182 proteins supplied by the Northeast Structural Genomics consortium. Gaussian processes, which capture trends beyond the reach of linear statistical models, distinguish between two main physico-chemical mechanisms driving crystallization. One is characterized by low levels of side chain entropy and has been extensively reported in the literature. The other identifies specific electrostatic interactions not previously described in the crystallization context. Because evidence for two distinct mechanisms can be gleaned both from crystal contacts and from solution conditions leading to successful crystallization, the model offers future avenues for optimizing crystallization screens based on partial structural information. The availability of crystallization data coupled with structural outcomes analyzed through state-of-the-art statistical models may thus guide macromolecular crystallization toward a more rational basis.

  5. Introduction to protein crystallization.

    Science.gov (United States)

    McPherson, Alexander; Gavira, Jose A

    2014-01-01

    Protein crystallization was discovered by chance about 150 years ago and was developed in the late 19th century as a powerful purification tool and as a demonstration of chemical purity. The crystallization of proteins, nucleic acids and large biological complexes, such as viruses, depends on the creation of a solution that is supersaturated in the macromolecule but exhibits conditions that do not significantly perturb its natural state. Supersaturation is produced through the addition of mild precipitating agents such as neutral salts or polymers, and by the manipulation of various parameters that include temperature, ionic strength and pH. Also important in the crystallization process are factors that can affect the structural state of the macromolecule, such as metal ions, inhibitors, cofactors or other conventional small molecules. A variety of approaches have been developed that combine the spectrum of factors that effect and promote crystallization, and among the most widely used are vapor diffusion, dialysis, batch and liquid-liquid diffusion. Successes in macromolecular crystallization have multiplied rapidly in recent years owing to the advent of practical, easy-to-use screening kits and the application of laboratory robotics. A brief review will be given here of the most popular methods, some guiding principles and an overview of current technologies.

  6. Isophthalate-Hydrazone 2D Zinc-Organic Framework: Crystal Structure, Selective Adsorption, and Tuning of Mechanochemical Synthetic Conditions.

    Science.gov (United States)

    Roztocki, Kornel; Jędrzejowski, Damian; Hodorowicz, Maciej; Senkovska, Irena; Kaskel, Stefan; Matoga, Dariusz

    2016-10-03

    A new layered mixed-linker metal-organic framework [Zn2(iso)2(pcih)2]n (MOF) built from isophthalate ions (iso(2-)) and 4-pyridinecarbaldehyde isonicotinoyl hydrazone (pcih) was prepared using both solution and mechanochemical methods. By use of the latter, the 2D MOF is obtained either in a one-mortar three-component grinding or on the way of a two-step mechanosynthesis. Tuning of mechanochemical synthetic conditions allowed us to identify both necessary and favorable factors for the solid-state formation of the MOF. Single-crystal X-ray diffraction reveals the presence of interdigitated layers in the ABAB arrangement and interlayer 0D cavities filled with guest molecules. Upon thermal activation, the dynamic framework exhibits stepwise and selective adsorption of CO2 over N2 as well as high-pressure H2 adsorption reaching maximum excess of 1.15 wt% at 77 K. The mechanochemical synthetic protocol is expanded to a few other interdigitated structures.

  7. Screening a Strain of Aspergillus niger and Optimization of Fermentation Conditions for Degradation of Aflatoxin B1

    OpenAIRE

    Wei Zhang; Beibei Xue; Mengmeng Li; Yang Mu; Zhihui Chen; Jianping Li; Anshan Shan

    2014-01-01

    Aflatoxin B1, a type of highly toxic mycotoxin produced by some species belonging to the Aspergillus genus, such as Aspergillus flavus and Aspergillus parasiticus, is widely distributed in feed matrices. Here, coumarin was used as the sole carbon source to screen microorganism strains that were isolated from types of feed ingredients. Only one isolate (ND-1) was able to degrade aflatoxin B1 after screening. ND-1 isolate, identified as a strain of Aspergillus niger using phylogenetic analysis ...

  8. Biological Macromolecule Crystallization Database

    Science.gov (United States)

    SRD 21 Biological Macromolecule Crystallization Database (Web, free access)   The Biological Macromolecule Crystallization Database and NASA Archive for Protein Crystal Growth Data (BMCD) contains the conditions reported for the crystallization of proteins and nucleic acids used in X-ray structure determinations and archives the results of microgravity macromolecule crystallization studies.

  9. Investigation into the influence of primary crystallization conditions on the mechanical properties and secondary processing behaviour of fluticasone propionate for carrier based dry powder inhaler formulations.

    Science.gov (United States)

    Kubavat, Harshal A; Shur, Jagdeep; Ruecroft, Graham; Hipkiss, David; Price, Robert

    2012-04-01

    To investigate the influence of primary crystallization conditions on the mechanical properties and secondary processing behaviour of fluticasone propionate (FP) for carrier based dry powder inhaler (DPI) formulations. Young's modulus of FP crystals produced using different anti-solvents was determined using nanoindentation. Physicochemical and surface interfacial properties via the cohesive-adhesive balance (CAB) approach to colloid probe atomic force microscopy (AFM) of air-jet micronised FP crystals were investigated. These data were correlated to in vitro aerosolization performance of binary and combination DPI formulations containing salmeterol xinafoate (SX). Young's modulus of FP crystals produced using different anti-solvents ranged from 0.6-12.4 GPa. Crystals with low Young's modulus required multiple passes in the microniser to reduce the particle size to less than 5 μm, whilst those with the highest Young's modulus required a single pass. CAB of micronized FP samples was similar with respect to lactose, however, their adhesive affinity to SX varied. Samples of FP with greatest adhesion to SX produced greater fine particle delivery of SX in combination DPI formulations. Crystallisation conditions may affect the mechanical properties of FP, and therefore secondary processing of the material and their interfacial properties and product performance in carrier based DPI formulations.

  10. Automating the application of smart materials for protein crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Khurshid, Sahir; Govada, Lata [Imperial College London, London SW7 2AZ (United Kingdom); EL-Sharif, Hazim F.; Reddy, Subrayal M. [University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Chayen, Naomi E., E-mail: n.chayen@imperial.ac.uk [Imperial College London, London SW7 2AZ (United Kingdom)

    2015-03-01

    The first semi-liquid, non-protein nucleating agent for automated protein crystallization trials is described. This ‘smart material’ is demonstrated to induce crystal growth and will provide a simple, cost-effective tool for scientists in academia and industry. The fabrication and validation of the first semi-liquid nonprotein nucleating agent to be administered automatically to crystallization trials is reported. This research builds upon prior demonstration of the suitability of molecularly imprinted polymers (MIPs; known as ‘smart materials’) for inducing protein crystal growth. Modified MIPs of altered texture suitable for high-throughput trials are demonstrated to improve crystal quality and to increase the probability of success when screening for suitable crystallization conditions. The application of these materials is simple, time-efficient and will provide a potent tool for structural biologists embarking on crystallization trials.

  11. A partnership model to improve population health screening for noncommunicable conditions and their common risk factors, Qazvin, Islamic Republic of Iran.

    Science.gov (United States)

    Alikhani, S; Damari, B

    2017-02-01

    Early findings and management of health conditions are among the key functions of health care systems. We developed a partnership framework to establish an extended primary health care-based selective screening service for the entire population of a small town as a key project of Qazvin Health Plan, Qazvin, Islamic Republic of Iran. Eight scientific associations and a diverse technical taskforce extensively reviewed evidence to adapt the grade A and B preventive recommendations of the American Preventive Service Taskforce. A list of 15 priority health conditions was identified and screening protocols were developed accordingly. Then strategies for working with private sector providers for better health care were applied to form our partnership model through which we ensured provision of screening services in 3 areas: service provision, quality and costs. Six private medical offices and a laboratory cooperated with the public health centre of the town to screen eligible residents. Preliminary analysis of the results suggests that the framework has successfully engaged private care providers.

  12. Novel Gyroscopic Mounting for Crystal Oscillators to Increase Short and Medium Term Stability under Highly Dynamic Conditions

    OpenAIRE

    2015-01-01

    In this paper, a gyroscopic mounting method for crystal oscillators to reduce the impact of dynamic loads on their output stability has been proposed. In order to prove the efficiency of this mounting approach, each dynamic load-induced instability has been analyzed in detail. A statistical study has been performed on the elevation angle of the g-sensitivity vector of Stress Compensated-cut (SC-cut) crystals. The analysis results show that the proposed gyroscopic mounting method gives good p...

  13. Crystallization and Mechanical Properties of Polypropylene under Processing-Relevant Cooling Conditions with respect to Isothermal Holding Time

    OpenAIRE

    Christopher Fischer; Dietmar Drummer

    2016-01-01

    For semicrystalline thermoplastics, aside from pressure and shear, the temperature-time behavior while cooling the melt significantly affects the geometry and degree of ordered structures (e.g., spherulite size, degree of crystallization, and crystal modification) and, as a consequence, the resulting global component properties. Previous research has shown that a higher isothermal holding temperature (e.g., mold temperature and chill-roll temperature) leads to the formation of more distinct o...

  14. An In Vitro Procedure for Phenotypic Screening of Growth Parameters and Symbiotic Performances in Lotus corniculatus Cultivars Maintained in Different Nutritional Conditions

    Directory of Open Access Journals (Sweden)

    Vladimir Totev Valkov

    2016-10-01

    Full Text Available The establishment of legumes crops with phenotypic traits that favour their persistence and competitiveness in mixed swards is a pressing task in sustainable agriculture. However, to fully exploit the potential benefits of introducing pasture-based grass-legume systems, an increased scientific knowledge of legume agronomy for screening of favourable traits is needed. We exploited a short-cut phenotypic screening as a preliminary step to characterize the growth capacity of three different Lotus corniculatus cvs cultivated in different nutritional conditions as well as the evaluation of their nodulation capacities. This experimental scheme, developed for legume species amenable to grow on agar plates conditions, may represent a very preliminary step to achieve phenotypic discrimination on different cultivars.

  15. An In Vitro Procedure for Phenotypic Screening of Growth Parameters and Symbiotic Performances in Lotus corniculatus Cultivars Maintained in Different Nutritional Conditions.

    Science.gov (United States)

    Valkov, Vladimir Totev; Chiurazzi, Maurizio

    2016-10-13

    The establishment of legumes crops with phenotypic traits that favour their persistence and competitiveness in mixed swards is a pressing task in sustainable agriculture. However, to fully exploit the potential benefits of introducing pasture-based grass-legume systems, an increased scientific knowledge of legume agronomy for screening of favourable traits is needed. We exploited a short-cut phenotypic screening as a preliminary step to characterize the growth capacity of three different Lotus corniculatus cvs cultivated in different nutritional conditions as well as the evaluation of their nodulation capacities. This experimental scheme, developed for legume species amenable to grow on agar plates conditions, may represent a very preliminary step to achieve phenotypic discrimination on different cultivars.

  16. Isolation and screening of rhizobia for auxin biosynthesis and growth promotion of mung bean (Vigna radiata L. seedlings under axenic conditions

    Directory of Open Access Journals (Sweden)

    Muhammad Ashfaq Anjum, Zahir Ahmad Zahir, Muhammad Arshad and Muhammad Ashraf

    2011-04-01

    Full Text Available A series of screening experiments to evaluate the effectiveness of rhizobia for producing auxins and improvegrowth and nodulation of mungbean (Vigna radiata L. were carried out under axenic conditions. Forty fouriolatess of rhizobia were isolated using standard procedures. Auxin biosynthesis by these rhizobial isolates wasdetermined in the absence and presence of L-Trp, a physiological precursor of auxins. Rhizobial isolates variedwidely in auxins biosynthesis capabilities. On the basis of auxins biosynthesis, a pouch experiment was conductedfor screening thirty four efficient isolates of rhizobia for the growth promotion of mung bean. Results of pouch studyshowed that inoculation with selected rhizobial isolates increased the root /shoot length, fresh, and dry shoot weightof mung bean up to 33, 59, 71, 148, 107 and 188%, respectively, over untreated control. Further studies are neededunder glasshouse and field conditions for confirmation of these results.

  17. An In Vitro Procedure for Phenotypic Screening of Growth Parameters and Symbiotic Performances in Lotus corniculatus Cultivars Maintained in Different Nutritional Conditions

    Science.gov (United States)

    Valkov, Vladimir Totev; Chiurazzi, Maurizio

    2016-01-01

    The establishment of legumes crops with phenotypic traits that favour their persistence and competitiveness in mixed swards is a pressing task in sustainable agriculture. However, to fully exploit the potential benefits of introducing pasture-based grass-legume systems, an increased scientific knowledge of legume agronomy for screening of favourable traits is needed. We exploited a short-cut phenotypic screening as a preliminary step to characterize the growth capacity of three different Lotus corniculatus cvs cultivated in different nutritional conditions as well as the evaluation of their nodulation capacities. This experimental scheme, developed for legume species amenable to grow on agar plates conditions, may represent a very preliminary step to achieve phenotypic discrimination on different cultivars. PMID:27754365

  18. Solubility Report of 1-Methyl-3,5-Dinitro-1H-1,2,4-Triazole (MDNT) and 2-Methyl-4,5-Dinitro-2H-1,2,3-Triazole 1-Oxide (MDNTO) for Co-Crystallization Screen

    Science.gov (United States)

    2015-11-01

    any method that will prevent disclosure of its contents or reconstruction of the document. Do not return to the originator. UNCLASSIFIED REPORT...crystallization screening of these energetic melt-cast materials . Solubility curves were constructed by evaluating the turbidity of solutions through a range of...Procedures 2 Materials 2 Solubility 2 Nuclear Magnetic Resonance 8 Results and Discussion 9 Conclusions 12 References 13 Distribution List 15

  19. A simple and effective plating method to screen polycyclic aromatic hydrocarbon-degrading bacteria under various redox conditions.

    Science.gov (United States)

    Um, Youngsoon; Chang, Matthew Wook; Holoman, Tracey Pulliam

    2010-09-01

    Agar plates with a polycyclic aromatic hydrocarbon (PAH) layer have been used to screen for microorganisms that degrade PAHs, leaving clear zones around colonies; however, there are several problems with previous methods such as undesired contamination in the fume hood and difficulty in controlling the amount of PAH on the plates. In this study, we developed a modified screening method to address the drawbacks encountered with previous screening methods. A uniform white layer of PAHs was generated by spreading PAHs dissolved in volatile solvents over a surface of solidified agar medium, followed by the evaporation of the solvents. An inoculation was then performed by spreading a molten agar medium containing microbial samples over the solidified agar medium with a PAH layer. Subsequently, the white PAH layer migrated to the surface of the molten agar medium. This essential modification enabled us not only to solve problems of the previous screening methods but also to prepare an agar plate with a PAH layer without a complicated experimental scheme in the anaerobic chamber. After solidification of the molten agar medium and incubation of the plates, clear zones were successfully detected around colonies with aerobic and anaerobic PAH-degrading microbial cultures.

  20. Establishment of intein-mediated protein ligation under denaturing conditions: C-terminal labeling of a single-chain antibody for biochip screening.

    Science.gov (United States)

    Sydor, Jens R; Mariano, Maria; Sideris, Steve; Nock, Steffen

    2002-01-01

    Intein-mediated protein ligation is a recently developed method that enables the C-terminal labeling of proteins. This technique requires a correctly folded intein mutant that is fused to the C-terminus of a target protein to create a thioester, which allows the ligation of a peptide with an N-terminal cysteine (1, 2). Here we describe the establishment of this method for the labeling, under denaturing conditions, of target proteins that are expressed insolubly as intein fusion proteins. A GFPuv fusion protein with the Mycobacterium xenopi gyrA intein was expressed in inclusion bodies in Escherichia coli and initially used as a model protein to verify intein cleavage activity under different refolding conditions. The intein showed activity after refolding in nondenaturing and slightly denaturing conditions. A construct of the same intein with an anti-neutravidin single-chain antibody was also expressed in an insoluble form. The intein-mediated ligation was established for this single chain antibody-intein fusion protein under denaturing conditions in 4 M urea to prevent significant precipitation of the fusion protein during the first refolding step. Under optimized conditions, the single-chain antibody was labeled with a fluorescent peptide and used for antigen screening on a biochip after final refolding. This screening procedure allowed the determination of binding characteristics of the scFv for avidin proteins in a miniaturized format.

  1. Flue gas conditioning for improved particle collection in electrostatic precipitators. First topical report, Results of laboratory screening of additives

    Energy Technology Data Exchange (ETDEWEB)

    Durham, M.D.

    1993-04-16

    Several tasks have been completed in a program to evaluate additives to improve fine particle collection in electrostatic precipitators. Screening tests and laboratory evaluations of additives are summarized in this report. Over 20 additives were evaluated; four were found to improve flyash precipitation rates. The Insitec particle analyzer was also evaluated; test results show that the analyzer will provide accurate sizing and counting information for particles in the size range of {le} 10 {mu}m dia.

  2. A high-throughput screening assay for assessing the viability of Cryptococcus neoformans under nutrient starvation conditions.

    Science.gov (United States)

    Dehdashti, Seameen J; Abbott, Jennifer; Nguyen, Dac-Trung; McKew, John C; Williamson, Peter R; Zheng, Wei

    2013-08-01

    Cryptococcus neoformans causes an estimated 600,000 AIDS-related deaths annually that occur primarily in resource-limited countries. Fluconazole and amphotericin B are currently available for the treatment of cryptococcal-related infections. However, fluconazole has limited clinical efficacy and amphotericin B requires intravenous infusion and is associated with high renal toxicity. Therefore, there is an unmet need for a new orally administrable anti-cryptococcal drug. We have developed a high-throughput screening assay for the measurement of C. neoformans viability in 1,536-well plate format. The signal-to-basal ratio of the ATP content assay was 21.9 fold with a coefficient of variation and Z' factor of 7.1% and 0.76, respectively. A pilot screen of 1,280 known compounds against the wild-type C. neoformans (strain H99) led to the identification of four active compounds including niclosamide, malonoben, 6-bromoindirubin-3'-oxime, and 5-[(4-ethylphenyl)methylene]-2-thioxo-4-thiazolidinone. These compounds were further tested against nine clinical isolates of C. neoformans, and their fungicidal activities were confirmed. The results demonstrate that this miniaturized C. neoformans assay is advantageous for the high-throughput screening of large compound collections to identify lead compounds for new anti-cryptococcal drug development.

  3. An efficient screening method for the isolation of heterotrophic bacteria influencing growth of diatoms under photoautotrophic conditions.

    Science.gov (United States)

    Zecher, Karsten; Jagmann, Nina; Seemann, Philipp; Philipp, Bodo

    2015-12-01

    Interactions between photoautotrophic diatoms and heterotrophic bacteria are important for the biogeochemical C-cycle in the oceans. Additionally, biofilms formed by diatoms and bacteria are the initiating step of biofouling processes, which causes high costs in shipping. Despite this ecological and economical importance, the knowledge about biochemical and molecular mechanisms underlying these interkingdom interactions is relatively small. For analyzing these mechanisms, laboratory model systems are required. In this study, an efficient screening method for isolating bacteria influencing photoautotrophic diatom growth was established. First, diatom cultures of Phaeodactylum tricornutum and Thalassiosira pseudonana were made axenic by applying β-lactam antibiotics. Second, a non-invasive method for measuring growth of multiple parallel diatom cultures by chlorophyll fluorescence was established. This method allowed semi-quantitative chlorophyll determination of cultures with up to 3 μg (chlorophyll) ml(-1). Axenic diatom cultures were then used for enriching bacteria and led to the isolation of 24 strains influencing growth of both diatom strains in various ways. For example, Rheinheimera sp. strain Tn16 inhibited growth of T. pseudonana, while it stimulated growth and cell aggregation of P. tricornutum. Thus, this screening method is appropriate for isolating heterotrophic bacteria showing different interactions with different diatom species ranging from synergistic to antagonistic. In consecutive applications, this method will be useful to screen for bacterial mutants with altered phenotypes regarding the influence on diatom growth.

  4. Crystallization and cooling conditions for the diogenite formation in the turbulent magma ocean of the asteroid 4 Vesta

    CERN Document Server

    Kawabata, Yusuke

    2016-01-01

    The asteroid 4 Vesta has been completely differentiated to core and mantle despite its small size, of which surface materials are howardite-eucrite-diogenite (HED) meteorites that we know the detailed petrology, and therefore, is a good target for understanding differentiation of terrestrial planets. A new differentiation model for crust formation was developed by taking magma ocean fluid dynamics, chemical equilibrium, presence of $^{26}$Al, and cooling into consideration with special care to crystal separation. The role of crystal size, thickness of the conductive lid, and fO2 are evaluated as parameters. The results show that large crystals (1cm) settle and form a km-thick cumulate layer of orthopyroxene with Mg# of 0.70-0.90 in ~20 thousand years, which almost agrees with the Mg# of diogenites, whereas thinner layers are formed if the grain size is smaller.

  5. conditions

    Directory of Open Access Journals (Sweden)

    M. Venkatesulu

    1996-01-01

    Full Text Available Solutions of initial value problems associated with a pair of ordinary differential systems (L1,L2 defined on two adjacent intervals I1 and I2 and satisfying certain interface-spatial conditions at the common end (interface point are studied.

  6. Enhancing ubiquitin crystallization through surface-entropy reduction.

    Science.gov (United States)

    Loll, Patrick J; Xu, Peining; Schmidt, John T; Melideo, Scott L

    2014-10-01

    Ubiquitin has many attributes suitable for a crystallization chaperone, including high stability and ease of expression. However, ubiquitin contains a high surface density of lysine residues and the doctrine of surface-entropy reduction suggests that these lysines will resist participating in packing interactions and thereby impede crystallization. To assess the contributions of these residues to crystallization behavior, each of the seven lysines of ubiquitin was mutated to serine and the corresponding single-site mutant proteins were expressed and purified. The behavior of these seven mutants was then compared with that of the wild-type protein in a 384-condition crystallization screen. The likelihood of obtaining crystals varied by two orders of magnitude within this set of eight proteins. Some mutants crystallized much more readily than the wild type, while others crystallized less readily. X-ray crystal structures were determined for three readily crystallized variants: K11S, K33S and the K11S/K63S double mutant. These structures revealed that the mutant serine residues can directly promote crystallization by participating in favorable packing interactions; the mutations can also exert permissive effects, wherein crystallization appears to be driven by removal of the lysine rather than by addition of a serine. Presumably, such permissive effects reflect the elimination of steric and electrostatic barriers to crystallization.

  7. Crystallization and Mechanical Properties of Polypropylene under Processing-Relevant Cooling Conditions with respect to Isothermal Holding Time

    Directory of Open Access Journals (Sweden)

    Christopher Fischer

    2016-01-01

    Full Text Available For semicrystalline thermoplastics, aside from pressure and shear, the temperature-time behavior while cooling the melt significantly affects the geometry and degree of ordered structures (e.g., spherulite size, degree of crystallization, and crystal modification and, as a consequence, the resulting global component properties. Previous research has shown that a higher isothermal holding temperature (e.g., mold temperature and chill-roll temperature leads to the formation of more distinct ordered structures and, therefore, can lead to greater stiffness and strength. Nevertheless, isothermal holding time during manufacturing is typically not taken into account. In this paper, fast scanning calorimetry (FSC measurements were taken using polypropylene to analyze the crystallization during idealized temperature-time profiles based on the dynamic temperature process and to investigate the crystallization behavior at different temperatures and isothermal holding times analytically. Furthermore, iPP foils were extruded and tested mechanically to investigate the knowledge gained experimentally. Analytical and mechanical results show that foils produced at the same isothermal holding temperature can obtain significantly different ordered structures and mechanical properties depending primarily on the isothermal holding time.

  8. Measurements of Pair Production Under Channelling Conditions by 70-180 GeV Photons Incident on Single Crystals

    CERN Multimedia

    2002-01-01

    This experiment will use the WA69 set-up to deliver a tagged photon beam in the energy range from 15~GeV to 150~GeV with a total angular spread of about @M~0.5~mrad. The incident photon direction is known to about 35~@mrad through the direction of the emitting electron. The photon beam is incident on an about 1~mm thick Ge single crystal in order to investigate pair production in single crystals. Above a certain energy threshold photons incident along crystal axis will show strongly increased pair production yi - the so-called .us Channelling Pair Production (ChPP). The produced pairs are analyzed in the @W-spectrometer. The large spread in incident photon angles offers an excellent opportunity to investigate in one single experiment the pair production in an angular region around a crystal axes and thereby compare ChPP with coherent (CPP) and incoherent (ICPP) processes. The very abrupt onset of ChPP (around threshold) will be measured and give a crucial test of the theoretical calculations. The differential...

  9. Effects of Magnesium and Ferric Ions on Crystallization of Calcium Sulfate Dihydrate Under the Simulated Conditions of Wet Flue-gas Desulfurization

    Institute of Scientific and Technical Information of China (English)

    GAO Xiang; HUO Wang; ZHONG Yi; LUO Zhong-yang; CEN Ke-fa; NI Ming-jiang; CHEN Le-ming

    2008-01-01

    The influences of magnesium and ferric ions in their different ratios on the rate of gypsum crystallization were studied under the conditions similar to those of wet flue-gas desulfurization(WFGD).The results show thataddition of both Mg2+ and Fe3+ increased induction time and decreased the growth efficiency up to 50% compared with the baseline(without impurities) depending on the concentration and the type of impurity.The effects of Mg2+ and Fe3+ on the surface energy and the rate of nucleation were estimated by employing the classical nucleation theory.The surface energy decreased by 8% and 14% with the addition of 0.02 mol/L magnesium or ferric ions,respectively,compared to the baseline.Mg2+ and Fe3+ made the growth rate of the (020),(021) and (040) faces of gypsum crystal a much greater reduction,which leads to the formation of needle crystals compared to the baseline which favors the formation of plate or flakes.Furthermore,an edge detection program was developed to quantify the effects of impurities on the filtration rate of gypsum product.The results show that the inhibition efficiency of the presence of 0.02 mol/L Mg2+ and Fe3+ on the filtration rate of gypsum crystal ranges from 22% to 39%.

  10. Large single crystal diamond grown in FeNiMnCo-S-C system under high pressure and high temperature conditions

    Science.gov (United States)

    Zhang, He; Li, Shangsheng; Su, Taichao; Hu, Meihua; Li, Guanghui; Ma, Hongan; Jia, Xiaopeng

    2016-11-01

    Large diamonds have successfully been synthesized from FeNiMnCo-S-C system at temperatures of 1255-1393 °C and pressures of 5.3-5.5 GPa. Because of the presence of sulfur additive, the morphology and color of the large diamond crystals change obviously. The content and shape of inclusions change with increasing sulfur additive. It is found that the pressure and temperature conditions required for the synthesis decrease to some extent with the increase of S additive, which results in left down of the V-shape region. The Raman spectra show that the introduction of additive sulfur reduces the quality of the large diamond crystals. The x-ray photoelectron spectroscopy (XPS) spectra show the presence of S in the diamonds. Furthermore, the electrical properties of the large diamond crystals are tested by a four-point probe and the Hall effect method. When sulfur in the cell of diamond is up to 4.0 wt.%, the resistance of the diamond is 9.628×105 Ω·cm. It is shown that the large single crystal samples are n type semiconductors. This work is helpful for the further research and application of sulfur-doped semiconductor large diamond. Project supported by the National Natural Science Foundation of China (Grant No. 51172089), the Education Department of Henan Province, China (Grant No. 12A430010), and the Fundamental Research Funds for the Universities of Henan Province, China (Grant No. NSFRF140110).

  11. Improved electronic interfaces for AT-cut quartz crystal microbalance sensors under variable damping and parallel capacitance conditions.

    Science.gov (United States)

    Arnau, A; García, J V; Jimenez, Y; Ferrari, V; Ferrari, M

    2008-07-01

    A new configuration of automatic capacitance compensation (ACC) technique based on an oscillatorlike working interface, which permits the tracking of the series resonant frequency and the monitoring of the motional resistance and the parallel capacitance of a thickness-shear mode quartz crystal microbalance sensor, is introduced. The new configuration permits an easier calibration of the system which, in principle, improves the accuracy. Experimental results are reported with 9 and 10 MHz crystals in liquids with different parallel capacitances which demonstrate the effectiveness of the capacitance compensation. Some frequency deviations from the exact series resonant frequency, measured by an impedance analyzer, are explained by the specific nonideal behavior of the circuit components. A tentative approach is proposed to solve this problem that is also common to previous ACC systems.

  12. Crystallization of biological macromolecules in a reduced gravity environment

    Science.gov (United States)

    Meehan, E. J., Jr.

    1979-01-01

    A battery of micro techniques were developed which allow the screening of a large number of conditions using only a small amount of the macromolecule. The need to develop methodologies for growing large crystals required for neutron diffraction studies is discussed.

  13. Crystallization and preliminary X-ray analysis of a phosphopentomutase from Bacillus cereus

    Energy Technology Data Exchange (ETDEWEB)

    Panosian, Timothy D.; Nannemann, David P.; Bachmann, Brian O.; Iverson, T.M. (Vanderbilt)

    2013-09-18

    Phosphopentomutases (PPMs) interconvert D-ribose 5-phosphate and {alpha}-D-ribose 1-phosphate to link glucose and nucleotide metabolism. PPM from Bacillus cereus was overexpressed in Escherichia coli, purified to homogeneity and crystallized. Bacterial PPMs are predicted to contain a di-metal reaction center, but the catalytically relevant metal has not previously been identified. Sparse-matrix crystallization screening was performed in the presence or absence of 50 mM MnCl{sub 2}. This strategy resulted in the formation of two crystal forms from two chemically distinct conditions. The crystals that formed with 50 mM MnCl{sub 2} were more easily manipulated and diffracted to higher resolution. These results suggest that even if the catalytically relevant metal is not known, the crystallization of putative metalloproteins may still benefit from supplementation of the crystallization screens with potential catalytic metals.

  14. Thermochemical micro imprinting of single-crystal diamond surface using a nickel mold under high-pressure conditions

    Science.gov (United States)

    Imoto, Yuji; Yan, Jiwang

    2017-05-01

    Single-crystal diamond is an important material for cutting tools, micro electro mechanical systems, optical devices, and semiconductor substrates. However, the techniques for producing microstructures on diamond surface with high efficiency and accuracy have not been established. This paper proposes a thermochemical imprinting method for transferring microstructures from a nickel (Ni) mold onto single-crystal diamond surface. The Ni mold was micro-structured by a nanoindenter and then pressed against the diamond surface under high temperature and pressure in argon atmosphere. Results show that microstructures on the Ni mold were successfully transferred onto the diamond surface, and their depth increased with both pressure and temperature. Laser micro-Raman spectroscopy, transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) analyses indicate that a graphite layer was formed over the contact area between diamond and Ni during pressing, and after washing by a mixed acid, the graphite layer could be completely removed. This study demonstrated the feasibility of a cost-efficient fabrication method for large-area microstructures on single-crystal diamond.

  15. Structural and phase transformations in iron-based alloy obtained in conditions of high cooling rate crystallization

    Science.gov (United States)

    Kovalevskaya, Zh. G.; Khimich, M. A.

    2016-11-01

    The production of parts by selective electron beam melting (SEBM) is accompanied by the formation of nonequilibrium structures. This is caused by the crystallization of alloys with high cooling rates. To evaluate the influence of cooling rate on the process of structural and phase transformations in the Fe-8Si-5Al-2C alloy, the electron beam melting of plasma coating was carried out. The dendritic structure was formed in the molten pool. The distance between dendritic branches of the second order was 2-5 µm. This corresponds to the cooling rate of about 103 K/s. The electron microscopy has shown that dendrites were formed by α-phase, while γ-phase was localized between α-phase crystals in form of intercalations. The secondary phases (intermetallic, aluminum and iron carbosilicides, aluminates and iron carboaluminates) are of sub-micron size and located in the α- and γ-phase boundary intersections or within the grains of the main phase. The microhardness of the alloy increases twofold. This suggests that complex hardening by solid-solution and dispersed hardening by the secondary phase particles occurs during crystallization with the above-mentioned cooling rate.

  16. SCREENING AND OPTIMIZATION OF CULTURE CONDITIONS FOR CELLULASE PRODUCTION BY ASPERGILLUS NIGER NSPR012 IN SUBMERGED FERMENTATION

    Directory of Open Access Journals (Sweden)

    Juliet Bamidele Akinyele

    2014-12-01

    Full Text Available This study aimed at screening of selected fungal strains and optimization of process parameters for cellulases production in submerged fermentation. Aspergillus niger NSPR012 was selected for further studies as the most potent in producing cellulase of high activity. Utilization of various agro-wastes as substitute tocarboxy methyl cellulose (CMC for cellulase production was also investigated. Among tested carbon sources, banana peels at a concentration of 5% was found to be the most effective carbon source. The cellulase production by Aspergillus niger NSPR012 in mineral salt medium attained maximum after 96 h of incubation. Maximum cellulase activity (0.466µmol/min/mL was obtained with locust beans as the best organic nitrogen source. The optimum incubation temperature and initial pH were 37°C and 5.5, respectively. With this information, banana peels could have good biotechnological potential for bio-products formation in which cellulase is one.

  17. Protein crystallization with paper

    Science.gov (United States)

    Matsuoka, Miki; Kakinouchi, Keisuke; Adachi, Hiroaki; Maruyama, Mihoko; Sugiyama, Shigeru; Sano, Satoshi; Yoshikawa, Hiroshi Y.; Takahashi, Yoshinori; Yoshimura, Masashi; Matsumura, Hiroyoshi; Murakami, Satoshi; Inoue, Tsuyoshi; Mori, Yusuke; Takano, Kazufumi

    2016-05-01

    We developed a new protein crystallization method that incorporates paper. A small piece of paper, such as facial tissue or KimWipes, was added to a drop of protein solution in the traditional sitting drop vapor diffusion technique, and protein crystals grew by incorporating paper. By this method, we achieved the growth of protein crystals with reducing osmotic shock. Because the technique is very simple and the materials are easy to obtain, this method will come into wide use for protein crystallization. In the future, it could be applied to nanoliter-scale crystallization screening on a paper sheet such as in inkjet printing.

  18. Prenatal screening and genetics

    DEFF Research Database (Denmark)

    Alderson, P; Aro, A R; Dragonas, T

    2001-01-01

    Although the term 'genetic screening' has been used for decades, this paper discusses how, in its most precise meaning, genetic screening has not yet been widely introduced. 'Prenatal screening' is often confused with 'genetic screening'. As we show, these terms have different meanings, and we...... examine definitions of the relevant concepts in order to illustrate this point. The concepts are i) prenatal, ii) genetic screening, iii) screening, scanning and testing, iv) maternal and foetal tests, v) test techniques and vi) genetic conditions. So far, prenatal screening has little connection...... with precisely defined genetics. There are benefits but also disadvantages in overstating current links between them in the term genetic screening. Policy making and professional and public understandings about screening could be clarified if the distinct meanings of prenatal screening and genetic screening were...

  19. Optimization of solvent-out crystallization conditions of orlistat at lower temperature%奥利司他低温溶析结晶条件的优化

    Institute of Scientific and Technical Information of China (English)

    闫同顺; 杨金艳

    2015-01-01

    The crystallization of orlistat was studied by the single factor test and the orthogonal experiment design�Factors influencing the orlistat crystallization,such as solvent types,seed,the amount of water,the concentration of the solution,stirring speed and cooling speed were investigated�By static crystallization experiments, the crystallization of methanol/water as the best system and its proportion were established�Also adding crystal seed can obviously improve the crystallization temperature of orlistat, as well as improving product purity and content�Based on single factor test,the orthogonal experiment design L9( 34 ) was carried out with all dynamic factors in 50 L crystallization reactor, as well as further optimization of water addition�Results show that the highest orlistat crystal content and recovery were obtained�Under the optimal conditions, the rate of the cooling temperature was 2 ℃/h, the initial concentration of orlistat was 30 g/L,adding the amount of the solvent water was 25%(V/V),twice to add,the 0�1% seed by weight of orlistat was added before crystallization,the condition of stirring speed was 250 r/min�By HPLC analysis,orlistat content was 98�6%,and yield was 85�3%.%为了寻找一种高效的奥利司他结晶工艺,对溶剂种类、晶种、反溶剂加入量、待结晶溶液浓度、搅拌转速和降温速度等因素进行了研究。通过静态结晶实验,确立了甲醇/水为最佳的结晶体系及其比例,加入晶种能明显提高奥利司他的析晶温度,提高产品含量和纯度。在此基础上,经正交试验设计L9(34),通过50 L结晶罐动态考察了各因素对奥利司他结晶产品含量和收率的影响,并进一步优化了加水方式。结果表明:按照2℃/h速率降温,初始奥利司他质量浓度为30 g/L,反溶剂水的加量为25%(体积分数),分2次加入,析晶前加入产品质量0�1%的晶种,搅拌转速250 r/min条件

  20. Alcohol Use Screening

    Science.gov (United States)

    ... Centers Diseases + Condition Centers Mental Health Medical Library Alcohol Use Screening (AUDIT-C) - Instructions The following questions ... this tool, there is also text-only version . Alcohol Use Screening (AUDIT-C) - Manual Instructions The following ...

  1. Predicting laser-induced bulk damage and conditioning for deuterated potassium di-hydrogen phosphate crystals using ADM (absorption distribution model)

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Z M; Spaeth, M L; Manes, K; Adams, J J; Carr, C W

    2010-02-26

    We present an empirical model that describes the experimentally observed laser-induced bulk damage and conditioning behavior in deuterated Potassium dihydrogen Phosphate (DKDP) crystals in a self-consistent way. The model expands on an existing nanoabsorber precursor model and the multi-step absorption mechanism to include two populations of absorbing defects, one with linear absorption and another with nonlinear absorption. We show that this model connects previously uncorrelated small-beam damage initiation probability data to large-beam damage density measurements over a range of ns pulse widths relevant to ICF lasers such as the National Ignition Facility (NIF). In addition, this work predicts the damage behavior of laser-conditioned DKDP and explains the upper limit to the laser conditioning effect. The ADM model has been successfully used during the commissioning and early operation of the NIF.

  2. Crystal Engineering of an nbo Topology Metal-Organic Framework for Chemical Fixation of CO₂ under Ambient Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wen-Yang; Chen, Yao; Niu, Youhong; Williams, Kia; Cash, Lindsay; Perez, Pastor J.; Wojtas, Lukasz; Cai, Jianfeng; Chen, Yu-Sheng; Ma, Shengqian [UC; (USF)

    2015-02-20

    Crystal engineering of the nbo metal–organic framework (MOF) platform MOF-505 with a custom-designed azamacrocycle ligand (1,4,7,10-tetrazazcyclododecane-N,N',N'',N'''-tetra-p-methylbenzoic acid) leads to a high density of well-oriented Lewis active sites within the cuboctahedral cage in MMCF-2, [Cu₂(Cu-tactmb)(H₂O)₃(NO₃)₂]. This MOF demonstrates high catalytic activity for the chemical fixation of CO₂ into cyclic carbonates at room temperature under 1 atm pressure.

  3. Crystal engineering of an nbo topology metal-organic framework for chemical fixation of CO2 under ambient conditions.

    Science.gov (United States)

    Gao, Wen-Yang; Chen, Yao; Niu, Youhong; Williams, Kia; Cash, Lindsay; Perez, Pastor J; Wojtas, Lukasz; Cai, Jianfeng; Chen, Yu-Sheng; Ma, Shengqian

    2014-03-03

    Crystal engineering of the nbo metal-organic framework (MOF) platform MOF-505 with a custom-designed azamacrocycle ligand (1,4,7,10-tetrazazcyclododecane-N,N',N'',N'''-tetra-p-methylbenzoic acid) leads to a high density of well-oriented Lewis active sites within the cuboctahedral cage in MMCF-2, [Cu2(Cu-tactmb)(H2O)3(NO3)2]. This MOF demonstrates high catalytic activity for the chemical fixation of CO2 into cyclic carbonates at room temperature under 1 atm pressure.

  4. Screening, identification, optimization of fermentation conditions, and extraction of secondary metabolites for the biocontrol of Rhizoctonia Solani AG-3

    Directory of Open Access Journals (Sweden)

    Taswar Ahsan

    2017-01-01

    Full Text Available In this study a strain of Streptomyces sp. was isolated from soil and identified by 16S rRNA gene sequencing technology. The strain was screened for antibiotics production effective against biocontrol of Rhizoctonia solani AG-3 to cure the target spot disease in tobacco. For enhance production of secondary metabolites, central composite design of response surface methodology (RSM was applied in submerged fermentation. The maximum metabolite production was using medium volume of 55 mL in 250 mL flask, agitation speed of 165 rpm, incubation temperature 30 °C, initial medium pH of 6.8 and inoculum size of 7%. Solvent extraction method was used to extract the secondary metabolites and active compounds were purified by silica gel column chromatography. The purified fractions were further investigated by gas chromatography-mass spectrophotometer (GC-MS. GC-MS analysis showed 48 compounds, among them 12 were active against pathogen. These findings indicated that the strain Streptomyces TA 1123 was a potential antagonist against R. solani AG-3.

  5. The emulsion crystallization of hydrogenated castor oil into long thin fibers

    Science.gov (United States)

    De Meirleir, Niels; Pellens, Linda; Broeckx, Walter; De Malsche, Wim

    2013-11-01

    The present study discusses the optimal crystal growth conditions required for the emulsion crystallization of hydrogenated castor oil (HCO) into several crystal morphologies. The best possible crystal shape is furthermore identified in case high rheology modifying performance is required. HCO was crystallized in a meso- and micro-continuous process which allowed for a controlled and fast screening of several crystal morphologies at different crystallization conditions. Applying high isothermal temperatures (above 55 °C) resulted in a combination of rosettes, thick fibers and thin fibers. At lower isothermal temperatures (below 55 °C) the shape gradually evolved to a combination of short needles, spherically shaped and/or irregularly shaped crystals. Crystals with the highest aspect ratio were obtained when crystals were grown between 30 °C and 45 °C and were subsequently reheated above 63 °C, forming high amounts of large thin fibrous crystals. When diluted to 0.25 wt% these fibrous crystals increased the low shear viscosity far better compared to the other crystal shapes.

  6. Physical activity, nutrition, screen time and sleep associated with body weight and physical condition in young children

    NARCIS (Netherlands)

    L'Hoir, Monique; Tetteroo, Susanne; Boere-Boonekamp, Magdalena M.; Kloeze, Elly; Bakker, Ingrid; Galindo Garre, Francisca; Naul, Roland

    2013-01-01

    The aim of this cross-sectional study was to explore the possible relationship between (un)healthy behaviour and (over)weight and physical condition in families with young children (4–7 years), in a village (30,000 inhabitants) in the eastern part of the Netherlands, close to Germany. It is one of

  7. Physical activity, nutrition, screen time and sleep associated with body weight and physical condition in young children

    NARCIS (Netherlands)

    L'Hoir, Monique; Tetteroo, Susanne; Boere-Boonekamp, Magda; Kloeze, Elly; Bakker, Ingrid; Galindo Garre, Francisca; Naul, Roland

    2013-01-01

    The aim of this cross-sectional study was to explore the possible relationship between (un)healthy behaviour and (over)weight and physical condition in families with young children (4–7 years), in a village (30,000 inhabitants) in the eastern part of the Netherlands, close to Germany. It is one of t

  8. Observation of trapped light induced by Dwarf Dirac-cone in out-of-plane condition for photonic crystals

    Science.gov (United States)

    Majumder, Subir; Biswas, Tushar; Bhadra, Shaymal K.

    2016-10-01

    Existence of out-of-plane conical dispersion for a triangular photonic crystal lattice is reported. It is observed that conical dispersion is maintained for a number of out-of-plane wave vectors (k z ). We study a case where Dirac like linear dispersion exists but the photonic density of states is not vanishing, called Dwarf Dirac cone (DDC) which does not support localized modes. We demonstrate the trapping of such modes by introducing defects in the crystal. Interestingly, we find by k-point sampling as well as by tuning trapped frequency that such a conical dispersion has an inherent light confining property and it is governed by neither of the known wave confining mechanisms like total internal reflection, band gap guidance. Our study reveals that such a conical dispersion in a non-vanishing photonic density of states induces unexpected intense trapping of light compared with those at other points in the continuum. Such studies provoke fabrication of new devices with exciting properties and new functionalities. Project supported by Director, CSIR-CGCRI, the DST, Government of India, and the CSIR 12th Plan Project (GLASSFIB), India.

  9. MyCrystals - a simple visual data management program for laboratory-scale crystallization experiments

    DEFF Research Database (Denmark)

    Løvgreen, Monika Nøhr; Løvgreen, Mikkel; Christensen, Hans Erik Mølager

    2009-01-01

    MyCrystals is designed as a user-friendly program to display crystal images and list crystallization conditions. The crystallization conditions entry fields can be customized to suit the experiments. MyCrystals is also able to sort the images by the entered crystallization conditions, which...

  10. Crystallization conditions and petrogenesis of the lava dome from the ˜900 years BP eruption of Cerro Machín Volcano, Colombia

    Science.gov (United States)

    Laeger, Kathrin; Halama, Ralf; Hansteen, Thor; Savov, Ivan P.; Murcia, Hugo F.; Cortés, Gloria P.; Garbe-Schönberg, Dieter

    2013-12-01

    The last known eruption at Cerro Machín Volcano (CMV) in the Central Cordillera of Colombia occurred ˜900 years BP and ended with the formation of a dacitic lava dome. The dome rocks contain both normally and reversely zoned plagioclase (An24-54), unzoned and reversely zoned amphiboles of dominantly tschermakite and pargasite/magnesio-hastingsite composition and olivine xenocrysts (Fo = 85-88) with amphibole/clinopyroxene overgrowth, all suggesting interaction with mafic magma at depth. Plagioclase additionally exhibits complex oscillatory zoning patterns reflecting repeated replenishment, fractionation and changes in intrinsic conditions in the magma reservoir. Unzoned amphiboles and cores of the reversely zoned amphiboles give identical crystallization conditions of 910 ± 30 °C and 360 ± 70 MPa, corresponding to a depth of about 13 ± 2 km, at moderately oxidized conditions (f = +0.5 ± 0.2 ΔNNO). The water content in the melt, calculated based on amphibole chemistry, is 7.1 ± 0.4 wt.%. Rims of the reversely zoned amphiboles are relatively enriched in MgO and yield higher crystallization temperatures (T = 970 ± 25 °C), slightly lower melt H2O contents (6.1 ± 0.7 wt.%) and overlapping pressures (410 ± 100 MPa). We suggest that these rims crystallized following an influx of mafic melt into a resident magma reservoir at mid-crustal depths, further supported by the occurrence of xenocrystic olivine. Crystallization of biotite, albite-rich plagioclase and quartz occurred at comparatively low temperatures (probably rock chemistry of the CMV lava dome dacites is homogenous. They have elevated (La/Nb)N ratios of 3.8-4.5, typical for convergent margin magmas, and display several geochemical characteristics of adakites. Both Sr and Nd isotope compositions (87Sr/86Sr ˜0.70497, 143Nd/144Nd ˜0.51267) are among the most radiogenic observed for the Northern Volcanic Zone of the Andes. They are distinct from oceanic crust that has been subducted in the region

  11. Microfluidic Device for Automated High-Throughput Protein Crystallization Screening by Osmotic Dewatering%基于渗透脱水的自动化蛋白质结晶高通量筛选芯片

    Institute of Scientific and Technical Information of China (English)

    罗娅慧; 李刚; 陈强; 赵建龙

    2012-01-01

    构建了一种基于渗透脱水模式的自动进样微流控结晶芯片.该芯片通过真空预脱气将包含蛋白质和结晶剂的液滴自动分配至结晶微腔阵列中,然后利用集成的一排包含不同浓度盐溶液的透析管道,通过渗透脱水方式经一层聚二甲基硅氧烷(PDMS)膜实现液滴的逐渐浓缩,使之趋于过饱和状态,进而形成结晶.此芯片可一次筛选较宽范围的过饱和状态,实现蛋白质结晶的快速优化.利用模式蛋白溶菌酶的结晶实验验证了该芯片的性能.%A self-dispensing and osmosis-based microfluidic crystallization device was reported. This device automatically dispenses droplets containing protein and precipitant into an array of crystallization chambers by pre-degassing, and then gradually concentrates these droplets at different rates by osmotic dewatering through a polydimethylsiboxane(PDMS) membrane using a row of integrated dialysis channels filled with different concentration of salt solution. This concentration process drives the protein/precipitant mixture into supersaturated , thus tending toward the crystallization state. This device allows for screening a wide range of supersatura-tion in one trial for rapid optimization of protein crystallization. The feasibility of this crystallization device is demonstrated using the model proteins of lysozyme.

  12. A novel microseeding method for the crystallization of membrane proteins in lipidic cubic phase.

    Science.gov (United States)

    Kolek, Stefan Andrew; Bräuning, Bastian; Stewart, Patrick Douglas Shaw

    2016-04-01

    Random microseed matrix screening (rMMS), in which seed crystals are added to random crystallization screens, is an important breakthrough in soluble protein crystallization that increases the number of crystallization hits that are available for optimization. This greatly increases the number of soluble protein structures generated every year by typical structural biology laboratories. Inspired by this success, rMMS has been adapted to the crystallization of membrane proteins, making LCP seed stock by scaling up LCP crystallization conditions without changing the physical and chemical parameters that are critical for crystallization. Seed crystals are grown directly in LCP and, as with conventional rMMS, a seeding experiment is combined with an additive experiment. The new method was used with the bacterial integral membrane protein OmpF, and it was found that it increased the number of crystallization hits by almost an order of magnitude: without microseeding one new hit was found, whereas with LCP-rMMS eight new hits were found. It is anticipated that this new method will lead to better diffracting crystals of membrane proteins. A method of generating seed gradients, which allows the LCP seed stock to be diluted and the number of crystals in each LCP bolus to be reduced, if required for optimization, is also demonstrated.

  13. Molecular studies of model surfaces of metals from single crystals to nanoparticles under catalytic reaction conditions. Evolution from prenatal and postmortem studies of catalysts.

    Science.gov (United States)

    Somorjai, Gabor A; Aliaga, Cesar

    2010-11-02

    Molecular level studies of metal crystal and nanoparticle surfaces under catalytic reaction conditions at ambient pressures during turnover were made possible by the use of instruments developed at the University of California at Berkeley. Sum frequency generation vibrational spectroscopy (SFGVS), owing to its surface specificity and sensitivity, is able to identify the vibrational features of adsorbed monolayers of molecules. We identified reaction intermediates, different from reactants and products, under reaction conditions and for multipath reactions on metal single crystals and nanoparticles of varying size and shape. The high-pressure scanning tunneling microscope (HP-STM) revealed the dynamics of a catalytically active metallic surface by detecting the mobility of the adsorbed species during catalytic turnover. It also demonstrated the reversible and adsorbate-driven surface restructuring of platinum when exposed to molecules such as CO and ethylene. Ambient pressure X-ray photoelectron spectroscopy (AP-XPS) detected the reversible changes of surface composition in rhodium-palladium, platinum-palladium, and other bimetallic nanoparticles as the reactant atmosphere changed from oxidizing to reducing. It was found that metal nanoparticles of less than 2 nm in size are present in higher oxidation states, which alters and enhances their catalytic activity. The catalytic nanodiode (CND) confirmed that a catalytic reaction-induced current flow exists at oxide-metal interfaces, which correlates well with the reaction turnover.

  14. Study on Direct Synthesis of Diphenyl Carbonate with Heterogeneous Catalytic Reaction (V) Screening Catalysts and Optimizing Synthesis Conditions

    Institute of Scientific and Technical Information of China (English)

    张光旭; 吴元欣; 马沛生; 田崎峰; 吴广文; 李定或; 王存文

    2003-01-01

    Pd/LaxPbyMnOz, Pd/C, Pd/molecular sieve and Pd-heteropoly acid catalysts for direct synthesis of diphenyl carbonate (DPC) by heterogeneous catalytic reaction were compared and the results of DPC synthesis indicated that the catalyst Pd/LaxPbyMnOz had higher activity. The Pd/LaxPbyMnOz catalyst and the support was characterized by XRD, SEM and TEM, the main phase was La0.62Pb0.38MnO3 and the average diameter could be about 25.4 nm. The optimum conditions for synthesis of DPC with Pd/LaxPbyMnOz were determined by orthogonal experiments and the experimental results showed that reaction temperature was the first factor of effect on the selectivity and yield of DPC, and the concentration of O2 in gas phase also had significant effect on selectivity of DPC. The optimum reaction conditions were catMyst/phenol mass ratio 1 to 50, pressure 4.5 MPa,volume concentration of O2 25%, reaction temperature 60° and reaction time 4 h. The maximum yield and average selectivity could reach 13% and 97% respectively in the batch operation.

  15. Impact parameter dependent electron capture by decelerated U{sup 91+} ions at 20 MeV/u using crystal channeling conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dauvergne, D. E-mail: d.dauvergne@ipnl.in2p3.fr; Braeuning-Demian, A.; Bosch, F.; Braeuning, H.; Chevallier, M.; Cohen, C.; Gumberidze, A.; L' Hoir, A.; Kirsch, R.; Kozhuharov, C.; Liesen, D.; Mokler, P.H.; Poizat, J.C.; Ray, C.; Stoehlker, Th.; Tarisien, M.; Testa, E.; Toleikis, S.; Toulemonde, M

    2003-05-01

    We present results of an experiment using decelerated U{sup 91+} ions, extracted from the GSI-ESR storage ring, and transmitted through a thin silicon crystal in channeling conditions. Charge state at emergence, secondary electron multiplicity and X-rays are measured simultaneously. These conditions allow to study the competition between mechanical electron capture (MEC) and radiative electron capture (REC) as a function of impact parameter. We observe that REC is the dominant charge exchange process for the best channeled ions, i.e. those travelling always far from the silicon target core electrons. For ions with high transverse energy, MEC into highly excited states is counterbalanced by enhanced ionization arising from a succession of close collisions along atomic rows.

  16. Protein crystallization using microfluidic technologies based on valves, droplets, and SlipChip.

    Science.gov (United States)

    Li, Liang; Ismagilov, Rustem F

    2010-01-01

    To obtain protein crystals, researchers must search for conditions in multidimensional chemical space. Empirically, thousands of crystallization experiments are carried out to screen various precipitants at multiple concentrations. Microfluidics can manipulate fluids on a nanoliter scale, and it affects crystallization twofold. First, it miniaturizes the experiments that can currently be done on a larger scale and enables crystallization of proteins that are available only in small amounts. Second, it offers unique experimental approaches that are difficult or impossible to implement on a larger scale. Ongoing development of microfluidic techniques and their integration with protein production, characterization, and in situ diffraction promises to accelerate the progress of structural biology.

  17. Evaluating the effects of buffer conditions and extremolytes on thermostability of granulocyte colony-stimulating factor using high-throughput screening combined with design of experiments.

    Science.gov (United States)

    Ablinger, Elisabeth; Hellweger, Monika; Leitgeb, Stefan; Zimmer, Andreas

    2012-10-15

    In this study, we combined a high-throughput screening method, differential scanning fluorimetry (DSF), with design of experiments (DoE) methodology to evaluate the effects of several formulation components on the thermostability of granulocyte colony stimulating factor (G-CSF). First we performed a primary buffer screening where we tested thermal stability of G-CSF in different buffers, pH values and buffer concentrations. The significance of each factor and the two-way interactions between them were studied by multivariable regression analysis. pH was identified as most critical factor regarding thermal stability. The most stabilizing buffer, sodium glutamate, and sodium acetate were determined for further investigations. Second we tested the effect of 6 naturally occurring extremolytes (trehalose, sucrose, ectoine, hydroxyectoine, sorbitol, mannitol) on the thermal stability of G-CSF, using a central composite circumscribed design. At low pH (3.8) and low buffer concentration (5 mM) all extremolytes led to a significant increase in thermal stability except the addition of ectoine which resulted in a strong destabilization of G-CSF. Increasing pH and buffer concentration led to an increase in thermal stability with all investigated extremolytes. The described systematic approach allowed to create a ranking of stabilizing extremolytes at different buffer conditions. Copyright © 2012. Published by Elsevier B.V.

  18. Tailoring of crystal phase and Néel temperature of cobalt monoxides nanocrystals with synthetic approach conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ravindra, A. V.; Behera, B. C.; Padhan, P. [Department of Physics, Indian Institute of Technology Madras, Chennai 600036 (India); Lebedev, O. I.; Prellier, W. [Laboratoire CRISMAT, CNRS UMR 6508, ENSICAEN, 6 Bd du Marechal Juin, F-14050 Caen Cedex (France)

    2014-07-21

    Cobalt monoxide (CoO) nanocrystals were synthesized by thermal decomposition of cobalt oleate precursor in a high boiling point organic solvent 1-octadecene. The X-ray diffraction pattern and transmission electron microscopy studies suggest that pure face-centered-cubic (fcc) phase of CoO can be synthesized in the temperature range of 569–575 K. Thermolysis product at higher synthesis temperature 585 K is a mixture of fcc and hexagonal-closed-packed (hcp) phases. These nanocrystals are single crystals of CoO and exhibit mixture of two types of morphologies; one is nearly spherical with 5–25 nm diameter, and other one is 5–10 nm thick flake. The pure fcc-CoO nanocrystals show enhanced, and mixture of fcc- and hcp-CoO nanocrystals show reduced antiferromagnetic ordering temperature. Such results provide new opportunities for optimizing and enhancing the properties and performance of cobalt oxide nanomaterials.

  19. Recent Progress of Microfluidic Techniques for Protein Crystallization and Screening%基于微流控技术的蛋白质结晶及其筛选方法的研究进展

    Institute of Scientific and Technical Information of China (English)

    朱丽娜; 祝莹; 方群

    2014-01-01

    微流控技术以其高通量、低消耗和集成化等优点成为蛋白质结晶微型化研究的重要手段。本文综述了基于微流控技术的蛋白质结晶技术和方法,主要包括微泵微阀、液滴( Droplet)、滑动芯片( SlipChip)以及液滴实验室( DropLab)等技术。此外,还针对当前膜蛋白在结构生物学研究中的重要地位,综述了应用于膜蛋白结晶的微流控技术的研究进展。%With the advantages of high throughput, low consumption and large-scale integration, microfluidics has proven to be a promising technique for protein crystallization and screening. This article reviews the recent progress of various microfluidic techniques successfully applied in protein crystallization, including PDMS-based valve and pump, droplet, SlipChip and DropLab. In addition, due to the high importance and great challenges of membrane proteins in structural biology, we further introduce the microfluidic techniques for crystallization of membrane proteins.

  20. 拟南芥抗氧化突变体筛选条件的建立%Establishment of the Screening Conditions of Arabidopsis thaliana Antioxidant Mutants

    Institute of Scientific and Technical Information of China (English)

    蒋春云

    2011-01-01

    [目的]建立筛选拟南芥抗氧化突变体的条件.[方法] 将灭菌的野生型拟南芥种子播种于MS培养基上,4 ℃层化2 d,并于23 ℃培养室中垂直放置培养4 d后,将幼苗转移至含有不同浓度的甲基紫精(MV)胁迫培养基中,倒置培养,比较不同MV浓度下根的弯曲生长情况,以根停止弯曲生长的MV浓度作为抗氧化胁迫突变体的筛选条件.[结果]野生型拟南芥幼苗的根在MV浓度为0.7 μmol/L时受到明显抑制,停止生长;在MV浓度低于0.7 μmol/L时能正常生长或被轻微抑制.[结论]确定筛选抗氧化突变体的MV浓度为0.7 μmol/L.%[ Objective ] The research aimed to establish the condition for screening the Arabidopsis thaliana antioxidant mutants. [ Method ]The sterilized seeds of wild-type Arabidopsis thaliana were sown on MS medium plates. Two days after stratification at 4 ℃, the plates were vertically placed in growth room of 23 ℃. Four days after seed germination, the four-day-old seedlings were transferred to the MS agar medium supplemented with different concentrations of methyl viologen (MV) and the plates were inverted with the roots pointing upward. It identified that the concentration of MV was the condition of screening the mutants, which can inhibited the root growth. [ Result]The growth of the roots of Arabidopsis thaliana seedlings were significantly inhibited and stopped when the concentration of MV was 0.7 μmol/L, while the concentration was lower than 0.7 μmol/L, the plants can grown normally or slightly inhibited. [ Conclusion]0.7 μmol/L of MV was the concentration for screening antioxidant mutants.

  1. Screening of Conditionally Reprogrammed Patient-Derived Carcinoma Cells Identifies ERCC3-MYC Interactions as a Target in Pancreatic Cancer.

    Science.gov (United States)

    Beglyarova, Natalya; Banina, Eugenia; Zhou, Yan; Mukhamadeeva, Ramilia; Andrianov, Grigorii; Bobrov, Egor; Lysenko, Elena; Skobeleva, Natalya; Gabitova, Linara; Restifo, Diana; Pressman, Max; Serebriiskii, Ilya G; Hoffman, John P; Paz, Keren; Behrens, Diana; Khazak, Vladimir; Jablonski, Sandra A; Golemis, Erica A; Weiner, Louis M; Astsaturov, Igor

    2016-12-15

    Even when diagnosed prior to metastasis, pancreatic ductal adenocarcinoma (PDAC) is a devastating malignancy with almost 90% lethality, emphasizing the need for new therapies optimally targeting the tumors of individual patients. We first developed a panel of new physiologic models for study of PDAC, expanding surgical PDAC tumor samples in culture using short-term culture and conditional reprogramming with the Rho kinase inhibitor Y-27632, and creating matched patient-derived xenografts (PDX). These were evaluated for sensitivity to a large panel of clinical agents, and promising leads further evaluated mechanistically. Only a small minority of tested agents was cytotoxic in minimally passaged PDAC cultures in vitro Drugs interfering with protein turnover and transcription were among most cytotoxic. Among transcriptional repressors, triptolide, a covalent inhibitor of ERCC3, was most consistently effective in vitro and in vivo causing prolonged complete regression in multiple PDX models resistant to standard PDAC therapies. Importantly, triptolide showed superior activity in MYC-amplified PDX models and elicited rapid and profound depletion of the oncoprotein MYC, a transcriptional regulator. Expression of ERCC3 and MYC was interdependent in PDACs, and acquired resistance to triptolide depended on elevated ERCC3 and MYC expression. The Cancer Genome Atlas analysis indicates ERCC3 expression predicts poor prognosis, particularly in CDKN2A-null, highly proliferative tumors. This provides initial preclinical evidence for an essential role of MYC-ERCC3 interactions in PDAC, and suggests a new mechanistic approach for disruption of critical survival signaling in MYC-dependent cancers. Clin Cancer Res; 22(24); 6153-63. ©2016 AACR. ©2016 American Association for Cancer Research.

  2. Crystal structure refinement of chromites from two achondrites, their T-f(O2) conditions, and implications

    Science.gov (United States)

    Lenaz, Davide; Schmitz, Birger

    2017-09-01

    Six Cr-spinel grains from NWA 6077 brachinite-like and NWA 725 winonaite achondrites have been studied by single-crystal X-ray diffraction and structural refinement. From a chemical point of view, spinels from NWA 6077 show Cr/(Cr + Al) (i.e., Cr#) and Mg/(Mg + Fe2+) (i.e., Mg#) values similar to other brachinites, while the Cr# of NWA 725 is lower than that of literature winonaites. Spinels from NWA 6077 and NWA 725 meteorites show similar cell edges, while the oxygen positional parameter is rather different being about 0.2629 for NWA 6077 and 0.2622 for NWA 725. Considering both parameters, NWA 725 shows structural features that are close to some terrestrial spinel occurrences as in komatiites, kimberlites, or included in diamonds; those from NWA 6077 show values that have no terrestrial analogs. Olivine-chromite closure temperature ranges from 737 to 765° C for NWA 725, being similar to that of literature winonaites and 846 to 884° C for NWA 6077. The logfO2 ranges from -19.8 to -20.5 and -17.0 to -17.9 for the two meteorites, respectively. The u values for terrestrial samples can give information about the cooling history of the samples. For the extraterrestrial samples, it seems that it can give information about the cooling only for spinels where it is lower than 0.2625. For higher values, it appears related only to the chemistry of the spinels.

  3. Crystallization conditions of porphyritic high-K calc-alkaline granitoids in the extreme northeastern Borborema Province, NE Brazil, and geodynamic implications

    Science.gov (United States)

    Campos, Benedita Cleide Souza; Vilalva, Frederico Castro Jobim; Nascimento, Marcos Antônio Leite do; Galindo, Antônio Carlos

    2016-10-01

    An integrated textural and chemical study on amphibole, biotite, plagioclase, titanite, epidote, and magnetite was conducted in order to estimate crystallization conditions, along with possible geodynamic implications, for six Ediacaran porphyritic high-K calc-alkaline granite plutons (Monte das Gameleiras, Barcelona, Acari, Caraúbas, Tourão, and Catolé do Rocha) intrusive into Archean to Paleoproterozoic rocks of the São José do Campestre (SJCD) and Rio Piranhas-Seridó (RPSD) domains, northern Borborema Province. The studied rocks include mainly porphyritic leucocratic monzogranites, as well as quartz-monzonites and granodiorites. Textures are marked by K-feldspar megacrysts (5-15 cm long) in a fine-to medium-grained matrix composed of quartz, plagioclase, amphibole, biotite, as well as titanite, epidote, Fesbnd Ti oxides, allanite, apatite, and zircon as accessory minerals. Amphibole, biotite and titanite share similar compositional variations defined by increasing Al and Fe, and decreasing Mg contents from the plutons emplaced into the SJCP (Monte das Gameleiras and Barcelona) towards those in the RPSD (Acari, Caraúbas, Tourão, and Catolé do Rocha). Estimated intensive crystallization parameters reveal a weak westward range of increasing depth of emplacement, pressure and temperature in the study area. The SJCD plutons (to the east) crystallized at shallower crustal depths (14-21 km), under slightly lower pressure (3.8-5.5 kbar) and temperature (701-718 °C) intervals, and high to moderate oxygen fugacity conditions (+0.8 plutons (to the west) were emplaced at slightly deeper depths (18-23 km), under higher, yet variable pressures (4.8-6.2 kbar), temperatures (723-776 °C), and moderate to low oxygen fugacity conditions (-1.0 < ΔFQM < +1.8). These results reinforce the contrasts between the tectono-strutuctural domains of São José do Campestre and Rio Piranhas-Seridó in the northern Borborema Province.

  4. Electrophoresis Gel Quantification with a Flatbed Scanner and Versatile Lighting from a Screen Scavenged from a Liquid Crystal Display (LCD) Monitor

    Science.gov (United States)

    Yeung, Brendan; Ng, Tuck Wah; Tan, Han Yen; Liew, Oi Wah

    2012-01-01

    The use of different types of stains in the quantification of proteins separated on gels using electrophoresis offers the capability of deriving good outcomes in terms of linear dynamic range, sensitivity, and compatibility with specific proteins. An inexpensive, simple, and versatile lighting system based on liquid crystal display backlighting is…

  5. Electrophoresis Gel Quantification with a Flatbed Scanner and Versatile Lighting from a Screen Scavenged from a Liquid Crystal Display (LCD) Monitor

    Science.gov (United States)

    Yeung, Brendan; Ng, Tuck Wah; Tan, Han Yen; Liew, Oi Wah

    2012-01-01

    The use of different types of stains in the quantification of proteins separated on gels using electrophoresis offers the capability of deriving good outcomes in terms of linear dynamic range, sensitivity, and compatibility with specific proteins. An inexpensive, simple, and versatile lighting system based on liquid crystal display backlighting is…

  6. The purification, crystallization and preliminary diffraction of a glycerophosphodiesterase from Enterobacter aerogenes

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Colin J.; Carr, Paul D.; Kim, Hye-Kyung; Liu, Jian-Wei; Ollis, David L., E-mail: ollis@rsc.anu.edu.au [The Research School of Chemistry, Australian National University, ACT 0200 (Australia)

    2006-07-01

    The metallo-glycerophosphodiesterase from E. aerogenes (GpdQ) has been cloned, expressed in E. coli and purified. Initial screening of crystallization conditions for this enzyme resulted in the identification of needles from one condition in a sodium malonate grid screen. Removal of the metals from the enzyme and subsequent optimization of these conditions led to crystals. The metallo-glycerophosphodiesterase from Enterobacter aerogenes (GpdQ) has been cloned, expressed in Escherichia coli and purified. Initial screening of crystallization conditions for this enzyme resulted in the identification of needles from one condition in a sodium malonate grid screen. Removal of the metals from the enzyme and subsequent optimization of these conditions led to crystals that diffracted to 2.9 Å and belonged to space group P2{sub 1}3, with unit-cell parameter a = 164.1 Å. Self-rotation function analysis and V{sub M} calculations indicated that the asymmetric unit contains two copies of the monomeric enzyme, corresponding to a solvent content of 79%. It is intended to determine the structure of this protein utilizing SAD phasing from transition metals or molecular replacement.

  7. A possibility of parallel and anti-parallel diffraction measurements on neutron diffractometer employing bent perfect crystal monochromator at the monochromatic focusing condition

    Indian Academy of Sciences (India)

    Yong Nam Choi; Shin Ae Kim; Sung Kyu Kim; Sung Baek Kim; Chang-Hee Lee; Pivel Mikula

    2004-07-01

    In a conventional diffractometer having single monochromator, only one position, parallel position, is used for the diffraction experiment (i.e. detection) because the resolution property of the other one, anti-parallel position, is very poor. However, a bent perfect crystal (BPC) monochromator at monochromatic focusing condition can provide a quite flat and equal resolution property at both parallel and anti-parallel positions and thus one can have a chance to use both sides for the diffraction experiment. From the data of the FWHM and the / measured on three diffraction geometries (symmetric, asymmetric compression and asymmetric expansion), we can conclude that the simultaneous diffraction measurement in both parallel and anti-parallel positions can be achieved.

  8. Comparison of Biomass and Lipid Production under Ambient Carbon Dioxide Vigorous Aeration and 3% Carbon Dioxide Condition Among the Lead Candidate Chlorella Strains Screened by Various Photobioreactor Scales

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Naoko [Univ. of Nebraska, Lincoln, NE (United States); Barnes, Austin [Univ. of Nebraska, Lincoln, NE (United States); Jensen, Travis [Univ. of Nebraska, Lincoln, NE (United States); Noel, Eric [Univ. of Nebraska, Lincoln, NE (United States); Andlay, Gunjan [Synaptic Research, Baltimore, MD (United States); Rosenberg, Julian N. [Johns Hopkins Univ., Baltimore, MD (United States); Betenbaugh, Michael J. [Johns Hopkins Univ., Baltimore, MD (United States); Guarnieri, Michael T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Oyler, George A. [Univ. of Nebraska, Lincoln, NE (United States); Johns Hopkins Univ., Baltimore, MD (United States); Synaptic Research, Baltimore, MD (United States)

    2015-09-01

    Chlorella species from the UTEX collection, classified by rDNA-based phylogenetic analysis, were screened based on biomass and lipid production in different scales and modes of culture. Lead candidate strains of C. sorokiniana UTEX 1230 and C. vulgaris UTEX 395 and 259 were compared between conditions of vigorous aeration with filtered atmospheric air and 3% CO2 shake-flask cultivation. We found that the biomass of UTEX 1230 produced 2 times higher at 652 mg L-1 dry weight under both ambient CO2 vigorous aeration and 3% CO2 conditions, while UTEX 395 and 259 under 3% CO2 increased to 3 times higher at 863 mg L-1 dry weight than ambient CO2 vigorous aeration. The triacylglycerol contents of UTEX 395 and 259 increased more than 30 times to 30% dry weight with 3% CO2, indicating that additional CO2 is essential for both biomass and lipid accumulation in UTEX 395 and 259.

  9. 牛乳清结晶条件的探索及其结晶体形貌%Exploration of Bovine Whey Crystallization Conditions and Morphology of Proteins Crystals

    Institute of Scientific and Technical Information of China (English)

    俞越钱

    2016-01-01

    以脱脂及去酪蛋白的牛乳清为原料,利用紫外分光光度法及SDS-PAGE电泳技术,在pH 4.7~8.0,NaCl浓度0.5~2.0 mol/L 条件下,对其结晶情况进行了研究。结果表明:牛乳清蛋白中的免疫球蛋白G(IgG)是一种理想的目标蛋白,而pH 7.0则是得到IgG的理想pH。最后还利用了工业相机及荧光倒置显微镜对牛乳清结晶体进行了拍摄,发现其中主要有长方晶、四角晶、菱方晶三种结晶体形貌。%With UV spectrophotometry and electrophoresis, degreased bovine whey after removal of ca-sein was studied in conditions of pH 4.7~8.0 and 0.5~2.0 mol/L NaCl. The results showed that immunoglob-ulin (IgG) was a kind of ideal target protein in bovine whey. Meanwhile, pH 7.0 was the ideal pH to obtain IgG. Finally, the crystallization behavior of whey was surveyed by an inverted fluorescence microscope and a high resolution digital camera. Furthermore, three kinds of morphology including orthorhombic, tetragonal and rhombus crystals were observed.

  10. Liquid Crystals

    Science.gov (United States)

    1990-01-01

    Thermochromic liquid crystals, or TLCs, are a type of liquid crystals that react to changes in temperature by changing color. The Hallcrest/NASA collaboration involved development of a new way to visualize boundary layer transition in flight and in wind tunnel testing of aircraft wing and body surfaces. TLCs offered a new and potentially better method of visualizing the boundary layer transition in flight. Hallcrest provided a liquid crystal formulation technique that afforded great control over the sensitivity of the liquid crystals to varying conditions. Method is of great use to industry, government and universities for aerodynamic and hydrodynamic testing. Company's principal line is temperature indicating devices for industrial use, such as non-destructive testing and flaw detection in electric/electronic systems, medical application, such as diagnostic systems, for retail sale, such as room, refrigerator, baby bath and aquarium thermometers, and for advertising and promotion specials. Additionally, Hallcrest manufactures TLC mixtures for cosmetic applications, and liquid crystal battery tester for Duracell batteries.

  11. 消化法检验旋毛虫病最适条件的筛选%The Screening of Optimum Conditions of Digestion Method for Detecting Trichinellosis

    Institute of Scientific and Technical Information of China (English)

    吴秀萍; 王迪; 李庶东; 孙召金; 刘明远

    2015-01-01

    Objective] To screen the optimum conditions including sedimentation temperature and sedimentation coefficient in collecting larvae after digestion,providing important reference data to improve the current“digestion method”for detecting trichinellosis in slaughtering animals.[Methods] 12 international reference Trichinella strains in-cluding 8 species and 4 genotypes were used experimentally to infect Balb/c mice,which were killed 40 dpi. The ratio of recovered muscle larvae and total muscle larvae in the digesting fluid were calculated respectively at 4℃and 25℃and at different time points,and then the sedimentation coefficient of different Trichinella species and genotypes were compared and analyzed. [Results] It was found through comparison that the muscle larvae recovery rates differed sig-nificantly in different Trichinella species and genotypes at different sedimentation temperature and time. The optimum conditions of digestion method for the known Trichinella species and genotypes were screened:the digested larvae should be settled at 4℃for at least 45min. [Conclusion] This study demonstrated the current international gold method for detection of Trichinellosis by means of digestion had certain bias resulting in misdetection. The screening optimum conditions of digestion method for detecting different Trichinella species and genotypes in the study provided the reli-able experimental data and reference value to improve international gold digestion method for detecting Trichinella.%[目的]筛选出“消化法”检测旋毛虫病的最适检测条件,即消化后收集虫体所需要的沉降温度和沉降时间,为改善现有屠宰动物旋毛虫病“消化法”检验技术提供重要的参考数据。[方法]将12个旋毛虫国际标准虫株(8个种和4个基因型)感染Balb/c小鼠,感染40天后剖杀,分别在4℃和25℃条件下计算不同时间点的回收肌幼虫百分比,计算不同温度不同时间点收

  12. Crystal Growth in Al72.9Ge27.1 Alloy Melt under Acoustic Levitation Conditions

    Institute of Scientific and Technical Information of China (English)

    YAN Na; DAI Fu-Ping; WANG Wei-Li; WEI Bing-Bo

    2011-01-01

    The nonequilibrium solidification of liquid Al72.9Ge27.1 hypoeutectic alloy is accomplished by using single-axis acoustic levitation.A maximum undercooling of 112K (0.16TL) is obtained for the alloy melt at a coofing rate of 50 K/s. The primary (Al) phase displays a morphological transition from coarse dendrite under a normal conditions to equiaxed grain under acoustic levitation.In the (Al)+(Ge) eutectic,the (Ge) phase exhibits a conspicuous branched growth morphology.Both the primary (Al) dendrites and (Al)+(Ge) eutectics are well refined and the solute content of the primary (Al) phase is extended under acoustic levitation.The calculated and experimental results indicate that the solute trapping effect becomes more intensive with the enhancement of bulk undercooling.

  13. Interaction between plate make and protein in protein crystallisation screening.

    Directory of Open Access Journals (Sweden)

    Gordon J King

    Full Text Available BACKGROUND: Protein crystallisation screening involves the parallel testing of large numbers of candidate conditions with the aim of identifying conditions suitable as a starting point for the production of diffraction quality crystals. Generally, condition screening is performed in 96-well plates. While previous studies have examined the effects of protein construct, protein purity, or crystallisation condition ingredients on protein crystallisation, few have examined the effect of the crystallisation plate. METHODOLOGY/PRINCIPAL FINDINGS: We performed a statistically rigorous examination of protein crystallisation, and evaluated interactions between crystallisation success and plate row/column, different plates of same make, different plate makes and different proteins. From our analysis of protein crystallisation, we found a significant interaction between plate make and the specific protein being crystallised. CONCLUSIONS/SIGNIFICANCE: Protein crystal structure determination is the principal method for determining protein structure but is limited by the need to produce crystals of the protein under study. Many important proteins are difficult to crystallize, so that identification of factors that assist crystallisation could open up the structure determination of these more challenging targets. Our findings suggest that protein crystallisation success may be improved by matching a protein with its optimal plate make.

  14. Identification of radionuclides for the spectroscopic radiation portal monitor for pedestrian screening under a low signal-to-noise ratio condition

    Energy Technology Data Exchange (ETDEWEB)

    Min, Eungi [Department of IT Convergence, Korea University, Seoul (Korea, Republic of); School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of); Ko, Mincheol [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of); Department of Bio-convergence Engineering, Korea University, Seoul (Korea, Republic of); Lee, Hakjae [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of); Research Institute of Health Science, Korea University, Seoul (Korea, Republic of); Kim, Yongkwon [NuCare Medical Systems, Incheon (Korea, Republic of); Research Institute of Health Science, Korea University, Seoul (Korea, Republic of); Joung, Jinhun [NuCare Medical Systems, Incheon (Korea, Republic of); Joo, Sung-Kwan [School of Electrical Engineering, Korea University, Seoul (Korea, Republic of); Lee, Kisung, E-mail: kisung@korea.ac.kr [School of Biomedical Engineering, Korea University, Seoul (Korea, Republic of); Department of Bio-convergence Engineering, Korea University, Seoul (Korea, Republic of); Department of Medical Devices, Korea University Guro Hospital, Seoul (Korea, Republic of)

    2014-09-11

    The spectroscopic radiation portal monitor (SPM) is widely used for homeland security. Many research groups are studying the radionuclide identification method which is one of the most important factors in the performance of the SPM using the large size of a thallium activated sodium iodide (NaI(Tl)) detector. In this study, we developed the radionuclide identification method for the SPM for pedestrian screening using a single NaI(Tl) detector that is small in size (2 in.), which is much smaller than those in the existing studies under the low signal-to-noise-ratio (SNR) condition. From the anomalous radionuclide spectrum, the noise component was effectively reduced by the wavelet decomposition and the proposed background subtraction method, and the signal component was enhanced by the principal component analysis. Finally, peak locations which have been determined by the peak search algorithm with a valley check method were compared with a pre-calibrated and constructed radionuclide database. To verify the radiation identification performance of the proposed method, experiments with various kinds of sources ({sup 137}Cs, {sup 133}Ba, {sup 22}Na, and {sup 57}Co) and different SNR values (from distances of 10–150 cm and for scan times of 1–5 s) were performed. Although the high-SNR condition was explored as well, most experiments were conducted under the low-SNR condition to verify the robustness and reproducibility of the proposed algorithm. The results showed that over 98.3% of the single radionuclide detection rate was achieved regardless of which radionuclides were used, up to 50 cm under the worst SNR condition (1 s of scan time) and up to 90 cm under the best SNR condition (5 s of scan time). Furthermore we achieved accurate identification of multiple radionuclides at 40 cm with only 1 s of scan time. The results show that the proposed algorithm is competitive with the commercial method and our radionuclide identification method can be successfully applied

  15. Influence of synthesis conditions on the crystal structure of the powder formed in the ZrO2 - Ce2O3/CeO2 system.

    Science.gov (United States)

    Popov, V. V.; Menushenkov, A. P.; Khubbutdinov, R. M.; Svetogorov, R. D.; Zubavichus, Ya V.; Sharapov, A. S.; Kurilkin, V. V.

    2016-09-01

    Influence of synthesis conditions (type of atmosphere, reduction and oxidation, annealing temperature) on the chemical composition and structure of the compounds formed in the “ZrO2 - Ce2O3 / CeO2” system has been investigated by X-ray absorption fine structure (XAFS) spectroscopy combined with X-ray diffraction (XRD) and thermogravimetric analysis (TGA). It is revealed that isothermal annealing of precursor at temperatures less than 1000 °C in air leads to formation of Ce0.5Zr0.5O2 powders with cubic fluorite-type structure (Fm-3m). Further increase of annealing temperatures above 1000 °C causes decomposition of formed crystal structure into two phases: cubic and tetragonal. Annealing in reduction hydrogen atmosphere causes formation of Ce4 + 2xCe3 + 2-2xZr2O7 + x compounds with intermediate valency of cerium, where value of x depends on the reducing conditions and treatment parameters of precursor. Annealing in vacuum at 1400 °C strongly reduces the content of Ce4+ in a powder samples and leads to formation of pyrochlore structure (space group Fd-3m) with practically Ce3+ valence state.

  16. Crystal structure of the Bacillus anthracis nucleoside diphosphate kinase and its characterization reveals an enzyme adapted to perform under stress conditions.

    Science.gov (United States)

    Misra, Gauri; Aggarwal, Anita; Dube, Divya; Zaman, Mohd Saif; Singh, Yogendra; Ramachandran, Ravishankar

    2009-08-01

    Nucleoside diphosphate kinases (Ndks) play an important role in a plethora of regulatory and metabolic functions. Inhibition of the B. anthracis Ndk mRNA results in the formation of nonviable aberrant spores. We report the characterization and crystal structure of the enzyme from B. anthracis nucleoside diphosphate kinase (BaNdk), the first from sporulating bacteria. The enzyme, although from a mesophilic source, is active at extremes of pH (3.5-10.5), temperature (10-95 degrees C) and ionic strength (0.25-4.0M NaCl). It exists as a hexamer that is composed of two SDS-stable trimers interacting in a back-to-back association; mutational analysis confirms that the enzyme is a histidine kinase. The high-resolution crystal structure reported here reveals an unanticipated change in the conformation of residues between 43 and 63 that also regulates substrate entry in other Ndks. A comparative structural analysis involving Ndks from seven mesophiles and three thermophiles has resulted in the delineation of the structure into relatively rigid and flexible regions. The analysis suggests that the larger number of intramolecular hydrogen bonds and to a lesser extent ionic interactions in BaNdk contributes to its high thermostability. Mutational analysis and Molecular Dynamics simulations were used to probe the role of a highly conserved Gly19 (present at the oligomeric interface in most of the Ndks). The results suggest that the mutation leads to a rigidification of those residues that facilitate substrate entry and consequently leads to a large reduction in the kinase activity. Overall, the enzyme characterization helps to understand its apparent adaptation to perform under stress conditions.

  17. Formation of solid thorium monoxide at near-ambient conditions as observed by neutron reflectometry and interpreted by screened hybrid functional calculations

    Science.gov (United States)

    He, Heming; Majewski, Jaroslaw; Allred, David D.; Wang, Peng; Wen, Xiaodong; Rector, Kirk D.

    2017-04-01

    Oxidation of a ∼1000 Å sputter-deposited thorium thin film at 150 °C in 100 ppm of flowing oxygen in argon produces the long-sought solid form of thorium monoxide. Changes in the scattering length density (SLD) distribution in the film over the 700-min experiment measured by in-situ, dynamic neutron reflectometry (NR) shows the densities, compositions and thickness of the various thorium oxides layers formed. Screened, hybrid density-functional theory calculations of potential thorium oxides aid interpretation, providing atomic-level picture and energetics for understanding oxygen migration. NR provided evidence of the formation of substoichiometric thorium oxide, ThOy (y thorium metal and its dioxide overcoat which grows inward, consuming the thorium at a rate of 2.1 Å/min while y increases until reaching 1:1 oxygen-to-thorium. Its presence indicates that kinetically-favored solid-phase ThO can be preferentially generated as a majority phase under the thermodynamically-favored ThO2 top layer at conditions close to ambient.

  18. [Early diagnosis of HIV in Primary Care in Spain. Results of a pilot study based on targeted screening based on indicator conditions, behavioral criteria and region of origin].

    Science.gov (United States)

    Agustí, Cristina; Martín-Rabadán, María; Zarco, José; Aguado, Cristina; Carrillo, Ricard; Codinachs, Roger; Carmona, Jose Manuel; Casabona, Jordi

    2017-06-16

    To estimate the prevalence of HIV infection in patients diagnosed with an indicator condition (IC) for HIV and/or risk behavior for their acquisition and/or coming from high prevalence countries. To determine the acceptability and feasibility of offering HIV testing based on IC and behavioral and origin criteria in Primary Care (PC). Cross-sectional study in a convenience sample. Six PC centers in Spain. The inclusion criteria were: patients between 16 and 65years old who presented at least one of the proposed ICs and/or at least one of the proposed behavioral and/or origin criteria. A total of 388 patients participated. HIV serology was offered to all patients who met the inclusion criteria. Description of IC frequency, behavioral and origin criteria. Prevalence of HIV infection. Level of acceptability and feasibility of the HIV screening based on IC and behavioral and origin criteria. A total of 174 patients had an IC (44.84%). The most common behavioral criterion was: having unprotected sex at some time in life with people who did not know their HIV status (298; 76.8%). Four HIV+ patients (1.03%) were diagnosed. All had an IC and were men who had sex with men. The level of acceptability in PC was high. Offering HIV testing to patients with IC and behavioral criteria is feasible and effective in PC. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.

  19. Screening efficiency and screen length of a linear vibrating screen using DEM 3D simulation

    Institute of Scientific and Technical Information of China (English)

    Wang Guifeng; Tong Xin

    2011-01-01

    The effect of screen length on the screening efficiency of particles is studied under various single parameter conditions including frequency,amplitude,vibration angle,and screen inclination.The Discrete Element Method (DEM) has been used to simulate the screening process.A functional relationship between screening efficiency and screen length is established.It is shown that screening efficiency and screen length have a complicated exponential relationship.Relationships between them are profoundly discussed and conclusions are easily drawn:low values of the parameters do not benefit screening; screening efficiency generally increases with screen length; screening efficiency reaches a plateau when these parameters are in range frequently encountered in practical applications.

  20. Synthesis, crystal and solution structures and antimicrobial screening of palladium(II) complexes with 2-(phenylselanylmethyl)oxolane and 2-(phenylselanylmethyl)oxane as ligands.

    Science.gov (United States)

    Bugarčić, Zorica M; Divac, Vera M; Kostić, Marina D; Janković, Nenad Ž; Heinemann, Frank W; Radulović, Niko S; Stojanović-Radić, Zorica Z

    2015-02-01

    Two novel Pd(II) complexes with 2-(phenylselanylmethyl)oxolane and 2-(phenylselanylmethyl)oxane as ligands were synthesized. The crystal and molecular structure of the complexes has been determined by single crystal X-ray diffraction. It turned out for both complexes that the two ligands are coordinated to Pd via Se atoms in a trans-fashion and the other two trans-positions are occupied by Cl ions. Detailed 1D- and 2D-NMR analyses revealed the existence of equilibrating trans-diastereomeric species differing in the configuration at four chiral centers (selenium and carbon) in the solution of the complexes. A computational study was also undertaken to assess the relative stabilities of the mentioned stereoisomeric species. The antimicrobial properties of the complexes were investigated against a series of human pathogenic bacterial and fungal strains. The complexes were shown to possess promising broad spectrum moderate antimicrobial activity that is more pronounced against fungal organisms. The noted activity could be completely attributed to the Pd(II) center, whereas the ligands probably mediate the transportation of a Pd(II) species across cell membranes.

  1. Automation in biological crystallization

    Science.gov (United States)

    Shaw Stewart, Patrick; Mueller-Dieckmann, Jochen

    2014-01-01

    Crystallization remains the bottleneck in the crystallographic process leading from a gene to a three-dimensional model of the encoded protein or RNA. Automation of the individual steps of a crystallization experiment, from the preparation of crystallization cocktails for initial or optimization screens to the imaging of the experiments, has been the response to address this issue. Today, large high-throughput crystallization facilities, many of them open to the general user community, are capable of setting up thousands of crystallization trials per day. It is thus possible to test multiple constructs of each target for their ability to form crystals on a production-line basis. This has improved success rates and made crystallization much more convenient. High-throughput crystallization, however, cannot relieve users of the task of producing samples of high quality. Moreover, the time gained from eliminating manual preparations must now be invested in the careful evaluation of the increased number of experiments. The latter requires a sophisticated data and laboratory information-management system. A review of the current state of automation at the individual steps of crystallization with specific attention to the automation of optimization is given. PMID:24915074

  2. Automation in biological crystallization.

    Science.gov (United States)

    Stewart, Patrick Shaw; Mueller-Dieckmann, Jochen

    2014-06-01

    Crystallization remains the bottleneck in the crystallographic process leading from a gene to a three-dimensional model of the encoded protein or RNA. Automation of the individual steps of a crystallization experiment, from the preparation of crystallization cocktails for initial or optimization screens to the imaging of the experiments, has been the response to address this issue. Today, large high-throughput crystallization facilities, many of them open to the general user community, are capable of setting up thousands of crystallization trials per day. It is thus possible to test multiple constructs of each target for their ability to form crystals on a production-line basis. This has improved success rates and made crystallization much more convenient. High-throughput crystallization, however, cannot relieve users of the task of producing samples of high quality. Moreover, the time gained from eliminating manual preparations must now be invested in the careful evaluation of the increased number of experiments. The latter requires a sophisticated data and laboratory information-management system. A review of the current state of automation at the individual steps of crystallization with specific attention to the automation of optimization is given.

  3. Vision Screening

    Science.gov (United States)

    ... of Prematurity Strabismus Stye (defined) Vision Screening Vision Screening Recommendations Loading... Most Common Searches Adult Strabismus Amblyopia Cataract Conjunctivitis Corneal Abrasions Dilating Eye ...

  4. Transmission electron microscopy for the evaluation and optimization of crystal growth

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, Hilary P.; Lin, Guowu; Barnes, Christopher O.; Sutkeviciute, Ieva; Krzysiak, Troy; Weiss, Simon C.; Reynolds, Shelley; Wu, Ying; Nagarajan, Veeranagu; Makhov, Alexander M.; Lawrence, Robert; Lamm, Emily; Clark, Lisa; Gardella, Timothy J.; Hogue, Brenda G.; Ogata, Craig M.; Ahn, Jinwoo; Gronenborn, Angela M.; Conway, James F.; Vilardaga, Jean-Pierre; Cohen, Aina E.; Calero, Guillermo

    2016-04-26

    The crystallization of protein samples remains the most significant challenge in structure determination by X-ray crystallography. Here, the effectiveness of transmission electron microscopy (TEM) analysis to aid in the crystallization of biological macromolecules is demonstrated. It was found that the presence of well ordered lattices with higher order Bragg spots, revealed by Fourier analysis of TEM images, is a good predictor of diffraction-quality crystals. Moreover, the use of TEM allowed (i) comparison of lattice quality among crystals from different conditions in crystallization screens; (ii) the detection of crystal pathologies that could contribute to poor X-ray diffraction, including crystal lattice defects, anisotropic diffraction and crystal contamination by heavy protein aggregates and nanocrystal nuclei; (iii) the qualitative estimation of crystal solvent content to explore the effect of lattice dehydration on diffraction and (iv) the selection of high-quality crystal fragments for microseeding experiments to generate reproducibly larger sized crystals. Applications to X-ray free-electron laser (XFEL) and micro-electron diffraction (microED) experiments are also discussed.

  5. Condition optimization and primer screening for ISSR-PCR of Demodex%蠕形螨ISSR-PCR的反应体系优化及引物筛选

    Institute of Scientific and Technical Information of China (English)

    刘艳荣; 刘付红; 肖克源; 郭淑玲; 冯玉新; 袁方曙

    2012-01-01

    目的 以蠕形螨的DNA为模板,对蠕形螨简单重复序列锚定PCR (ISSR-PCR)反应体系优化并对ISSR引物进行筛选,为ISSR分析奠定基础.方法 用自然沉降法收集山羊蠕形螨,用基因组DNA提取试剂盒提取山羊蠕形螨DNA,并以此为模板,以(CA)8RG(R为1分子的嘧啶)为引物,利用正交实验法,从Mg2+浓度、引物用量、dNTPs、DNA模板用量和TaqDNA聚合酶以及退火温度对蠕形螨ISSR-PCR反应体系进行优化,并以优化的反应体系筛选ISSR-PCR的引物.结果 ISSR-PCR 25 μL最佳反应体系包括:0.4 mmol/L Mg2+、30 pmol引物、30~60 ng模板DNA、2u Taq酶,最佳退火温度为49℃、循环35次.筛选出10条条带清晰、多态性好、重复性高的引物.结论 筛选出蠕形螨ISSR-PCR最佳反应体系和理想的引物,为蠕形螨的分子生物学研究奠定了基础.%Objective To optimize conditions and screening for primers for inter-simple sequence repeat-anchored (IS-SR-PCR) of Demodex, using genome DNA as the template, preparing for the genetic diversity research of Demodex with ISSR mark. Methods After mites were rinsed and precipitated in double distilled water (DDW), the genome DNA of Demodex was extracted with a kit. Then experiments were carried out using DNA of Demodex as the template, and (CA) 8 RG as the primer. The orthogonal array was conducted, and the involved factors were as follows: concentrations of Mg2+ , dNTPs, primers, template DNA and Taq DNA polymerase and return temperature. An optimal reaction system of ISSR-PCR of Demodex was established, through which an optimal primer was obtained. Results An optimal 25 (xL of ISSR-PCR amplification system contained 2.0 mmol/L of Mg2+ , 0. 4 mmol/L of dNTPs, 30-60 ng of template DNA, 30 pmol of primers, and 2U of Taq DNA polymerase. The optional return temperature for the primer was 49 t, and the cycle index was 35. 10 primers were selected, with clear bands, good polymorphism and high repetition. Conclusion

  6. Kumdykolite, kokchetavite, and cristobalite crystallized in nanogranites from felsic granulites, Orlica-Snieznik Dome (Bohemian Massif): not an evidence for ultrahigh-pressure conditions

    Science.gov (United States)

    Ferrero, Silvio; Ziemann, Martin A.; Angel, Ross J.; O'Brien, Patrick J.; Wunder, Bernd

    2016-01-01

    A unique assemblage including kumdykolite and kokchetavite, polymorphs of albite and K-feldspar, respectively, together with cristobalite, micas, and calcite has been identified in high-pressure granulites of the Orlica-Snieznik dome (Bohemian Massif) as the product of partial melt crystallization in preserved nanogranites. Previous reports of both kumdykolite and kokchetavite in natural rocks are mainly from samples that passed through the diamond stability field. However, because the maximum pressure recorded in these host rocks is <3 GPa, our observations indicate that high pressure is not required for the formation of kumdykolite and kokchetavite, and their presence is not therefore an indicator of ultrahigh-pressure conditions. Detailed microstructural and microchemical investigation of these inclusions indicates that such phases should instead be regarded as (1) a direct mineralogical criteria to identify former melt inclusions with preserved original compositions, including H2O and CO2 contents and (2) indicators of rapid cooling of the host rocks. Thus, the present study provides novel criteria for the interpretation of melt inclusions in natural rocks and allows a more rigorous characterization of partial melts during deep subduction to mantle depth as well as their behavior on exhumation.

  7. Effects of annealing conditions on crystallization of the CZTS absorber and photovoltaic properties of Cu(Zn,Sn)(S,Se){sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Duy-Cuong, E-mail: cuong.nguyenduy@hust.edu.vn [Nano Optoelectronics Laboratory, Advanced Institute for Science and Technology, Hanoi University of Science and Technology, No.1 Dai Co Viet, Hai Ba Trung, Hanoi (Viet Nam); Ito, Seigo [Department of Electrical Engineering and Computer Sciences, Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2280 (Japan); Dung, Dang Viet Anh [School of Chemical Engineering, Hanoi University of Science and Technology, No.1 Dai Co Viet, Hai Ba Trung, Hanoi (Viet Nam)

    2015-05-25

    Highlights: • CZTS films annealed under H{sub 2}S and Se ambient showed a different characterization. • The crystallizing temperature of CZTS films annealed under H{sub 2}S is higher than Se ambient. • Cell parameters of CZTS solar cells annealed Se ambient is better than H{sub 2}S ambient. • 4.94% efficiency of CZTSSe solar cells annealed under Se ambient was obtained. - Abstract: Cu(Zn,Sn)S{sub 2} (CZTS) nanoparticles were synthesized by hot-injection method. Cu(Zn,Sn)(S,Se){sub 2} (CZTSSe) solar cells were fabricated by printing method using CZTS nanocrystallites on molybdenum/glass substrate. The effects of annealing conditions such as temperature and ambient gas on microstructure and photovoltaic properties were investigated. CZTS films annealed in H{sub 2}S ambient shows low crystallinity, being peeled off easily, and poor photovoltaic characteristics, namely, the parameters of the best cell are short-circuit current density (J{sub SC}) of 4.8 mA/cm{sup 2}, open-circuit voltage (V{sub OC}) of 0.59 V, fill factor (FF) of 0.39, and conversion efficiency (η) of 1.12%. Meanwhile, CZTS films annealed under Se vapor shows high crystallinity and high cell performance: the parameters of the best cell are J{sub SC} = 26.2 mA/cm{sup 2}, V{sub OC} = 0.39, FF = 0.48, and η = 4.94%.

  8. Screening of an Actinomyces Producing Cranine and Fermentational Conditions%一株产蓝色素放线菌的筛选及发酵研究

    Institute of Scientific and Technical Information of China (English)

    全桂静; 邢继双

    2012-01-01

    One strain of actinomyces which can produce cyanine is screened,and named Cya-5.The conditions of cyanine fermentation have been studied,and the results show that the suitable formula of medium is that glycerin 20 g/L,KNO3 1 g/L,K2HPO4 0.5 g/L,MgSO4 · 7 H2O 0.5 g/L,FeSO4 · 7 H2O 0.01 g/L,NaCl 0.5 g/L,pH=8.5,100 mL/250 mL triangle bottle,temperature 30 ℃ fermentation 96 h,and A590 of fermented liquid is 1.202.The crude extracting pigment is obtained by alkali sink method,and its colourity is 45.8.%从土壤中筛选到1株蓝色素产量较高的放线菌,命名为Cya-5.对蓝色素发酵条件进行研究,结果显示发酵培养基的配方为甘油20 g/L、KNO31 g/L,K2HPO40.5 g/L,MgSO4.7H2O 0.5 g/L,FeSO4.7H2O 0.01 g/L,NaCl 0.5 g/L,pH=8.5,装液量为100 mL/250 mL三角瓶、30℃发酵96 h,发酵液的A590总值达到12.02.利用碱沉法提取发酵液中的色素物质,粗提物色价可达到45.8.

  9. Photonic crystal-encoded suspension array and its application in screening malignant tumors%光子晶体编码液相芯片技术与肿瘤筛查

    Institute of Scientific and Technical Information of China (English)

    杨子学; 陈宝安; 顾忠泽

    2014-01-01

    肿瘤筛查中通常采用多种肿瘤标志物的联合检测以提高诊断率。因此,为了提高筛查效率,亟需一种多元分析技术应用于肿瘤筛查。液相芯片技术是由基因微阵列生物芯片技术演变而来的多元分析技术。它由编码微球、探针分子、目标分子和报告分子四部分组成,可用于目标物的定量分析。微球编码技术是液相芯片技术的研究热点,本文中涉及的光子晶体编码是光学编码策略的一种,具有良好的稳定性和解码性能。长期研究表明,光子晶体编码液相芯片在肿瘤筛查、诊断中应用前景广阔。本文综述了光子晶体编码液相芯片技术的基本原理、技术特点及在肿瘤筛查中的应用现状。%Multiple tumor makers are needed to improve the diagnostic rate of the simultaneously detection of malignant tumors through screening. Therefore, multiplex detection technology is urgently required to improve the screening efficiency. Suspension arrays are multiplex detection method based on gene microarrays. It consists of encoded microbeads, probes, targets, and report molecules are applied to analyze targets quantitatively. The microbead encoding strategy is a hotspot in suspension array research. The photonic crystal encoding mentioned in this review is a type of optical encoding that is very stable and easily decoded. Photonic suspension arrays have broad prospects in the screening and diagnosis of malignant tumors through long-term studies. This review summarizes the basic principle, classification, and characteristics of photonic suspension arrays and their application in the screening of malignant tumors.

  10. The influence of boron on the crystal structure and properties of mullite. Investigations at ambient, high-pressure, and high-temperature conditions

    Energy Technology Data Exchange (ETDEWEB)

    Luehrs, Hanna

    2013-11-21

    Mullite is one of the most important synthetic compounds for advanced structural and functional ceramic materials. The crystal structure of mullite with the composition Al{sub 2}[Al{sub 2+2x}Si{sub 2-2x}]O{sub 10-x} can incorporate a large variety of foreign cations, including (amongst others) significant amounts of boron. However, no chemical or crystal structure analyses of boron-mullites (B-mullites) were available prior to this work, thus representing the key aspects of this thesis. Furthermore, the influence of boron on selected properties of mullite under ambient, high-temperature, and high-pressure conditions are addressed. Starting from a 3:2 mullite composition (Al{sub 4.5}Si{sub 1.5}O{sub 9.75}), the initial hypothesis for this study was a 1:1 isomorphous replacement of silicon by boron according to the coupled substitution mechanism: 2 Si{sup 4+} + O{sup 2-} → 2 B{sup 3+} + □. Based on a series of compounds synthesized from sol-gel derived precursors at ambient pressure and 1200 C, the formation conditions and physical properties of B-mullites were investigated. The formation temperature for B-mullites decreases with increasing boron-content, as revealed by thermal analyses. An anisotropic development of lattice parameters is observed: Whereas lattice parameters a and b only exhibit minor changes, a linear relationship between lattice parameter c and the amount of boron in the crystal structure was established, on the basis of prompt gamma activation analyses (PGAA) and Rietveld refinements. According to this relationship about 15% of the silicon in mullite can be replaced by boron yielding single-phase B-mullite. B-mullites with significantly higher (∝ factor 3) boron-contents in the mullite structure were also observed but the respective samples contain alumina impurities. Fundamental new details regarding the response of B-mullite to high-temperature and highpressure are presented in this thesis. On the one hand, long-term thermal stability at

  11. Effect of non-hydrostatic conditions on the elastic behaviour of magnetite: an in situ single-crystal X-ray diffraction study

    Science.gov (United States)

    Gatta, G. Diego; Kantor, I.; Boffa Ballaran, T.; Dubrovinsky, L.; McCammon, C.

    2007-11-01

    The high-pressure elastic behaviour and the pressure-induced structural evolution of synthetic magnetite were investigated up to 11.11(5) GPa by means of in situ single-crystal X-ray diffraction with a diamond anvil cell, using the mix methanol:ethanol:water = 16:3:1 as pressure-transmitting medium and the ruby-fluorescence method for pressure-calibration. The evolution of the ruby R1-fluorescence line with P, with a drastic increase of the full-width-at-half-maximum (FWHM) of the Lorentzian profile at P > 9 GPa, shows that the P-medium is not hydrostatic above 9 GPa. Such a condition is well reflected by the drastic increase (by 20-22%) of the FWHM of the diffraction peak profiles of magnetite, by the behaviour of the Eulerian finite strain versus normalized pressures plot ( f e - F e plot) and by the slight EoS-misfit. However, the diffraction data collected during decompression showed a reversible/complete restoration of the diffraction profiles and of the elastic behaviour in the f e - F e plot. The reflection conditions dictated by the Fdbar 3m space group confirm that symmetry of magnetite is maintained within the P-range investigated. The structural refinements performed at 0.0001, 4.99(3) and 9.21(8) GPa show that the evolution of the oxygen u-parameter is almost constant within the P-range investigated. A weighted linear regression through the data points gives only a slight negative slope and no discontinuity is observed within the P-range investigated. A similar continuous behaviour is also observed in the evolution of the T- and M-polyhedral volumes, bond distances and angles with P. On the basis of data reported in this study, it appears that the elastic behaviour and the structural evolution of magnetite is drastically influenced by the experimental conditions (i.e., hydrostatic or non-hydrostatic), and diffraction data of magnetite collected under non-hydrostatic conditions are unusable for a reliable description of the elastic behaviour and for the

  12. Crystals in crystals

    DEFF Research Database (Denmark)

    Christensen, Claus H.; Schmidt, I.; Carlsson, A.;

    2005-01-01

    A major factor governing the performance of catalytically active particles supported on a zeolite carrier is the degree of dispersion. It is shown that the introduction of noncrystallographic mesopores into zeolite single crystals (silicalite-1, ZSM-5) may increase the degree of particle dispersion...... of the zeolite particles, particularly after thermal treatment. When using mesoporous zeolites, the particles were evenly distributed throughout the mesopore system of the zeolitic support, even after calcination, leading to nanocrystals within mesoporous zeolite single crystals....

  13. A Few Good Crystals Please

    Science.gov (United States)

    Judge, Russell A.; Snell, Edward H.

    1999-01-01

    Part of the challenge of macromolecular crystal growth for structure determination is obtaining an appropriate number of crystals with a crystal volume suitable for X-ray analysis. In this respect an understanding of the effect of solution conditions on macromolecule nucleation rates is advantageous. This study investigated the effects of solution conditions on the nucleation rate and final crystal size of two crystal systems; tetragonal lysozyme and glucose isomerase. Batch crystallization plates were prepared at given solution concentration and incubated at set temperatures over one week. The number of crystals per well with their size and axial ratios were recorded and correlated with solution conditions. Duplicate experiments indicate the reproducibility of the technique. Results for each system showing the effect of supersaturation, incubation temperature and solution pH on nucleation rates will be presented and discussed. In the case of lysozyme, having optimized solution conditions to produce an appropriate number of crystals of a suitable size, a batch of crystals were prepared under exactly the same conditions. Fifty of these crystals were analyzed by x-ray techniques. The results indicate that even under the same crystallization conditions, a marked variation in crystal properties exists.

  14. Strain screen and condition optimization of synthesis arbutin by fermentation%发酵合成熊果苷菌种筛选及优化

    Institute of Scientific and Technical Information of China (English)

    朱松洁; 蔡圣宝; 籍保平; 吴薇

    2012-01-01

    Arbutin is the main component in cosmetic industry. The producing methods include chemical synthesis, plants exactraction and biosynthesis. Biosynthesis has many advantages of low levels of pollution, low cost and high efficiency. In this paper, 22 strains of fungus, bacterium and yeast were used for arbutin production screening. The fermentation liquor was used for arbutin detection and quantification with HPLC. The results indicated that the highest arbutin producing strain was Rhizopus oryzae. The optimal fermentation conditions for arbutin producing using R. oryzae were hydroquinone 50mmol/L; maltose as synthesis precursor and ratios of hydroquinone to maltose 1:3.%熊果苷是现代美白化妆品的主要原料,其生产方法包括化学合成法、植物提取法和生物合成法.生物合成法生产熊果苷具有污染小、成本低、效率高等一系列特点,在熊果苷生产中独具优势.本研究对22种包括丝状真菌、酵母菌以及细菌等不同微生物发酵生产熊果苷的能力进行筛选,并用高效液相色谱法对发酵生产的熊果苷进行定量比较.结果表明:米根霉、白地霉、酵母910,酵母904以及枯草芽孢杆菌可以利用对苯二酚发酵生产熊果苷,其中以米根霉的产量最高,产量达到441.30mg/L.对米根霉发酵生产熊果苷进行单因素条件优化,最终得到在对苯二酚浓度为50mmol/L、糖基供体为麦芽糖以及对苯二酚和麦芽糖比例为1:3的条件下,发酵效果较好.

  15. Purification of a Multidrug Resistance Transporter for Crystallization Studies

    Directory of Open Access Journals (Sweden)

    Kamela O. Alegre

    2015-03-01

    Full Text Available Crystallization of integral membrane proteins is a challenging field and much effort has been invested in optimizing the overexpression and purification steps needed to obtain milligram amounts of pure, stable, monodisperse protein sample for crystallography studies. Our current work involves the structural and functional characterization of the Escherichia coli multidrug resistance transporter MdtM, a member of the major facilitator superfamily (MFS. Here we present a protocol for isolation of MdtM to increase yields of recombinant protein to the milligram quantities necessary for pursuit of structural studies using X-ray crystallography. Purification of MdtM was enhanced by introduction of an elongated His-tag, followed by identification and subsequent removal of chaperonin contamination. For crystallization trials of MdtM, detergent screening using size exclusion chromatography determined that decylmaltoside (DM was the shortest-chain detergent that maintained the protein in a stable, monodispersed state. Crystallization trials of MdtM performed using the hanging-drop diffusion method with commercially available crystallization screens yielded 3D protein crystals under several different conditions. We contend that the purification protocol described here may be employed for production of high-quality protein of other multidrug efflux members of the MFS, a ubiquitous, physiologically and clinically important class of membrane transporters.

  16. Crystal science fundamentals

    OpenAIRE

    Ramachandran, V.; Halfpenny, PJ; Roberts, KJ

    2017-01-01

    The fundamentals of crystal science notably crystallography, crystal chemistry, crystal defects, crystal morphology and the surface chemistry of crystals are introduced with particular emphasis on organic crystals.

  17. Heroin crystal nephropathy.

    Science.gov (United States)

    Bautista, Josef Edrik Keith; Merhi, Basma; Gregory, Oliver; Hu, Susie; Henriksen, Kammi; Gohh, Reginald

    2015-06-01

    In this paper we present an interesting case of acute kidney injury and severe metabolic alkalosis in a patient with a history of heavy heroin abuse. Urine microscopy showed numerous broomstick-like crystals. These crystals are also identified in light and electron microscopy. We hypothesize that heroin crystalizes in an alkaline pH, resulting in tubular obstruction and acute kidney injury. Management is mainly supportive as there is no known specific therapy for this condition. This paper highlights the utility of urine microscopy in diagnosing the etiology of acute kidney injury and proposes a novel disease called heroin crystal nephropathy.

  18. Screening in liver disease

    Institute of Scientific and Technical Information of China (English)

    Paolo Del Poggio; Marzio Mazzoleni

    2006-01-01

    A disease is suitable for screening if it is common, if the target population can be identified and reached and if both a good screening test and an effective therapy are available. Of the most common liver diseases only viral hepatitis and genetic hemochromatosis partially satisfy these conditions. Hepatitis C is common, the screening test is good and the therapy eliminates the virus in half of the cases, but problems arise in the definition of the target population. In fact generalized population screening is not endorsed by international guidelines,although some recommend screening immigrants from high prevalence countries. Opportunistic screening (case finding) of individuals with classic risk factors,such as transfusion before 1992 and drug addiction,is the most frequently used strategy, but there is disagreement whether prison inmates, individuals with a history of promiscuous or traumatic sex and health care workers should be screened. In a real practice setting the performance of opportunistic screening by general practitioners is low but can be ameliorated by training programs. Screening targeted to segments of the population or mass campaigns are expensive and therefore interventions should be aimed to improve opportunistic screening and the detection skills of general practitioners. Regarding genetic hemochromatosis there is insufficient evidence for population screening, but individual physicians can decide to screen racial groups with a high prevalence of the disease, such as people in early middle age and of northern European origin. In the other cases opportunistic screening of high risk individuals should be performed, with a high level of suspicion in case of unexplained liver disease, diabetes, juvenile artropathy, sexual dysfunction and skin pigmentation.

  19. Tuning solubility and stability of hydrochlorothiazide co-crystals.

    Science.gov (United States)

    Sanphui, Palash; Rajput, Lalit

    2014-02-01

    Hydrochlorothiazide (HCT), C7H8ClN3O4S2, is a diuretic BCS (Biopharmaceutics Classification System) class IV drug which has primary and secondary sulfonamide groups. To modify the aqueous solubility of the drug, co-crystals with biologically safe co-formers were screened. Multi-component molecular crystals of HCT were prepared with nicotinic acid, nicotinamide, succinamide, p-aminobenzoic acid, resorcinol and pyrogallol using liquid-assisted grinding. The co-crystals were characterized by FT-IR spectroscopy, powder X-ray diffraction (PXRD) and differential scanning calorimetry. Single crystal structures were obtained for four of them. The N-H...O sulfonamide catemer synthons found in the stable polymorph of pure HCT are replaced in the co-crystals by drug-co-former heterosynthons. Isostructural co-crystals with nicotinic acid and nicotinamide are devoid of the common sulfonamide dimer/catemer synthons. Solubility and stability experiments were carried out for the co-crystals in water (neutral pH) under ambient conditions. Among the six binary systems, the co-crystal with p-aminobenzoic acid showed a sixfold increase in solubility compared with pure HCT, and stability up to 24 h in an aqueous medium. The co-crystals with nicotinamide, resorcinol and pyrogallol showed only a 1.5-2-fold increase in solubility and transformed to HCT within 1 h of the dissolution experiment. An inverse correlation is observed between the melting points of the co-crystals and their solubilities.

  20. A hetero-micro-seeding strategy for readily crystallizing closely related protein variants.

    Science.gov (United States)

    Islam, Mohammad M; Kuroda, Yutaka

    2017-09-01

    Protein crystallization remains difficult to rationalize and screening for optimal crystallization conditions is a tedious and time consuming procedure. Here, we report a hetero-micro-seeding strategy for producing high resolution crystals of closely related protein variants, where micro crystals from a readily crystallized variant are used as seeds to develop crystals of other variants less amenable to crystallization. We applied this strategy to Bovine Pancreatic Trypsin Inhibitor (BPTI) variants, which would not crystallize using standard crystallization practice. Out of six variants in our analysis, only one called BPTI-[5,55]A14G formed well behaving crystals; and the remaining five (A14GA38G, A14GA38V, A14GA38L, A14GA38I, and A14GA38K) could be crystallized only using micro-seeds from the BPTI-[5,55]A14G crystal. All hetero-seeded crystals diffracted at high resolution with minimum mosaicity, retaining the same space group and cell dimension. Moreover, hetero-micro-seeding did not introduce any biases into the mutant's structure toward the seed structure, as demonstrated by A14GA38I structures solved using micro-seeds from A14GA38G, A14GA38L and A14GA38I. Though hetero-micro-seeding is a simple and almost naïve strategy, this is the first direct demonstration of its workability. We believe that hetero-micro-seeding, which is contrasting with the popular idea that crystallization requires highly purified proteins, could contribute a new tool for rapidly solving protein structures in mutational analysis studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Cancer Screening

    Directory of Open Access Journals (Sweden)

    Krishna Prasad

    2004-10-01

    Full Text Available Cancer screening is a means to detect cancer early with the goal of decreasing morbidity and mortality. At present, there is a reasonable consensus regarding screening for breast, cervical and colorectal cances and the role of screening is under trial in case of cancers of the lung,  ovaries and prostate. On the other hand, good screening tests are not available for some of the commonest cancers in India like the oral, pharyngeal, esophageal and stomach cancers.

  2. Cancer Screening

    OpenAIRE

    Krishna Prasad

    2004-01-01

    Cancer screening is a means to detect cancer early with the goal of decreasing morbidity and mortality. At present, there is a reasonable consensus regarding screening for breast, cervical and colorectal cances and the role of screening is under trial in case of cancers of the lung,  ovaries and prostate. On the other hand, good screening tests are not available for some of the commonest cancers in India like the oral, pharyngeal, esophageal and stomach cancers.

  3. Using Microfluidics to Decouple Nucleation and Growth of Protein Crystals.

    Science.gov (United States)

    Shim, Jung-Uk; Cristobal, Galder; Link, Darren R; Thorsen, Todd; Fraden, Seth

    2007-01-01

    A high throughput, low volume microfluidic device has been designed to decouple the physical processes of protein crystal nucleation and growth. This device, called the Phase Chip, is constructed out of poly(dimethylsiloxane) (PDMS) elastomer. One of the Phase Chip's innovations is to exploit surface tension forces to guide each drop to a storage chamber. We demonstrate that nanoliter water-in-oil drops of protein solutions can be rapidly stored in individual wells thereby allowing the screening of 1000 conditions while consuming a total of only 10 mug protein on a 20 cm(2) chip. Another significant advance over current microfluidic devices is that each well is in contact with a reservoir via a dialysis membrane through which only water and other low molecular weight organic solvents can pass, but not salt, polymer, or protein. This enables the concentration of all solutes in a solution to be reversibly, rapidly, and precisely varied in contrast to current methods, such as the free interface diffusion or sitting drop methods, which are irreversible. The Phase Chip operates by first optimizing conditions for nucleation by using dialysis to supersaturate the protein solution, which leads to nucleation of many small crystals. Next, conditions are optimized for crystal growth by using dialysis to reduce the protein and precipitant concentrations, which leads small crystals to dissolve while simultaneously causing only the largest ones to grow, ultimately resulting in the transformation of many small, unusable crystals into a few large ones.

  4. [Studies on expression, purification, crystal growth and optimization of putative transcription factor LytR from Streptococcus pneumoniae].

    Science.gov (United States)

    Min, Xun; Zhong, Wen; Zhao, Shasha; Dong, Jie; Dong, Shanshan; Zhou, Aie; Yan, Wenjuan; Wang, Deqiang

    2013-08-01

    The aim of the present study was to obtain the crystal of transcription factor LytR of streptococcus pneumoniae for X-ray crystal structure and function analysis. The LytR gene of D39 strains from Streptococcus pneumoniae (S. pn) was cloned into the prokaryotic expression vector pET32a(+), then overexpression was obtained in the E. coli BL21 (DE3) through transformation of the recombinant plasmid that had been verified by colony PCR and sequencing. Soluble fusion protein with His-tag highly expressed by the induction of 0.5 mmol/L IPTG and was purified by a three step procedure, the purity of the purified LytR recombinant protein was over 90%. Preliminary screening of crystallization conditions was performed using the hanging-drop vapour-diffusing method with Hampton Crystal screen and PEG screen kits. The protein crystals X-ray diffraction data were collected from a single crystal and more stick crystals whose X-ray diffraction reached 4.0 A were obtained. These works laid the foundation for further research on the 3D structure of putative transcription factor LytR and its biological aspects.

  5. A robust and scalable microfluidic metering method that allows protein crystal growth by free interface diffusion

    Science.gov (United States)

    Hansen, Carl L.; Skordalakes, Emmanuel; Berger, James M.; Quake, Stephen R.

    2002-12-01

    Producing robust and scalable fluid metering in a microfluidic device is a challenging problem. We developed a scheme for metering fluids on the picoliter scale that is scalable to highly integrated parallel architectures and is independent of the properties of the working fluid. We demonstrated the power of this method by fabricating and testing a microfluidic chip for rapid screening of protein crystallization conditions, a major hurdle in structural biology efforts. The chip has 480 active valves and performs 144 parallel reactions, each of which uses only 10 nl of protein sample. The properties of microfluidic mixing allow an efficient kinetic trajectory for crystallization, and the microfluidic device outperforms conventional techniques by detecting more crystallization conditions while using 2 orders of magnitude less protein sample. We demonstrate that diffraction-quality crystals may be grown and harvested from such nanoliter-volume reactions.

  6. A robust and scalable microfluidic metering method that allows protein crystal growth by free interface diffusion

    Science.gov (United States)

    Hansen, Carl L.; Skordalakes, Emmanuel; Berger, James M.; Quake, Stephen R.

    2002-01-01

    Producing robust and scalable fluid metering in a microfluidic device is a challenging problem. We developed a scheme for metering fluids on the picoliter scale that is scalable to highly integrated parallel architectures and is independent of the properties of the working fluid. We demonstrated the power of this method by fabricating and testing a microfluidic chip for rapid screening of protein crystallization conditions, a major hurdle in structural biology efforts. The chip has 480 active valves and performs 144 parallel reactions, each of which uses only 10 nl of protein sample. The properties of microfluidic mixing allow an efficient kinetic trajectory for crystallization, and the microfluidic device outperforms conventional techniques by detecting more crystallization conditions while using 2 orders of magnitude less protein sample. We demonstrate that diffraction-quality crystals may be grown and harvested from such nanoliter-volume reactions. PMID:12486223

  7. Classical and quantum Coulomb crystals

    CERN Document Server

    Bonitz, M; Baumgartner, H; Henning, C; Filinov, A; Block, D; Arp, O; Piel, A; Kading, S; Ivanov, Y; Melzer, A; Fehske, H; Filinov, V

    2008-01-01

    Strong correlation effects in classical and quantum plasmas are discussed. In particular, Coulomb (Wigner) crystallization phenomena are reviewed focusing on one-component non-neutral plasmas in traps and on macroscopic two-component neutral plasmas. The conditions for crystal formation in terms of critical values of the coupling parameters and the distance fluctuations and the phase diagram of Coulomb crystals are discussed.

  8. Coulomb crystallization in classical and quantum systems

    Science.gov (United States)

    Bonitz, Michael

    2007-11-01

    Coulomb crystallization occurs in one-component plasmas when the average interaction energy exceeds the kinetic energy by about two orders of magnitude. A simple road to reach such strong coupling consists in using external confinement potentials the strength of which controls the density. This has been succsessfully realized with ions in traps and storage rings and also in dusty plasma. Recently a three-dimensional spherical confinement could be created [1] which allows to produce spherical dust crystals containing concentric shells. I will give an overview on our recent results for these ``Yukawa balls'' and compare them to experiments. The shell structure of these systems can be very well explained by using an isotropic statically screened pair interaction. Further, the thermodynamic properties of these systems, such as the radial density distribution are discussed based on an analytical theory [3]. I then will discuss Coulomb crystallization in trapped quantum systems, such as mesoscopic electron and electron hole plasmas in coupled layers [4,5]. These systems show a very rich correlation behavior, including liquid and solid like states and bound states (excitons, biexcitons) and their crystals. On the other hand, also collective quantum and spin effects are observed, including Bose-Einstein condensation and superfluidity of bound electron-hole pairs [4]. Finally, I consider Coulomb crystallization in two-component neutral plasmas in three dimensions. I discuss the necessary conditions for crystals of heavy charges to exist in the presence of a light component which typically is in the Fermi gas or liquid state. It can be shown that their exists a critical ratio of the masses of the species of the order of 80 [5] which is confirmed by Quantum Monte Carlo simulations [6]. Familiar examples are crystals of nuclei in the core of White dwarf stars, but the results also suggest the existence of other crystals, including proton or α-particle crystals in dense matter

  9. The construction of the CMS electromagnetic calorimeter: crystal assembly

    CERN Multimedia

    2005-01-01

    This photogallery describes the whole sequence of crystal assembly up to the so-called supermodules of 1700 PWO crystals each. Figures 1-6: submodule (10 crystals + their APDs) assembly with alveola structures. Figs. 7-11: module assembly. Each module is composed by 400 or 500 crystals. Figs. 13-17: supermodule assembly, thermal screen and monitoring, transport.

  10. The effect of different crystal conditions of filler metal on vacuum brazing of TiAl alloy and 42CrMo

    Institute of Scientific and Technical Information of China (English)

    Zhu Ying; Zhang Mo; Wang Guojian; Li Wenyi; Kang Hui; Qu Ping

    2007-01-01

    Ti-based filler metals made by transient solidification and normal crystallization were selected for the vacuum brazing of the TiAl alloy and 42CrMo under different processing parameters. The results show that the tensile strength of the joint of transient solidified filler metal is higher than that of normal crystallized filler metal under the same processing parameters. By the analysis of scanning electron microscope(SEM) and X-ray diffracting (XRD) , it is found that the higher strength maybe caused by the generating of TiAl , TiNi and TiCu at the interface of joint made by transient solidified filler metal.

  11. Coherent pair production in deformed crystals with a complex base

    CERN Document Server

    Mkrtchyan, A R; Saharian, A A

    2006-01-01

    We investigate the coherent electron-positron pair creation by high-energy photons in a periodically deformed single crystal with a complex base. The formula for the corresponding differential cross-section is derived for an arbitrary deformation field. The conditions are specified under which the influence of the deformation is considerable. The case is considered in detail when the photon enters into the crystal at small angles with respect to a crystallographic axis. The results of the numerical calculations are presented for $\\mathrm{SiO}_{2}$ single crystal and Moliere parametrization of the screened atomic potentials in the case of the deformation field generated by the acoustic wave of $S$ type. In dependence of the parameters, the presence of deformation can either enhance or reduce the pair creation cross-section. This can be used to control the parameters of the positron sources for storage rings and colliders.

  12. Double screening

    Energy Technology Data Exchange (ETDEWEB)

    Gratia, Pierre [Department of Physics, University of Chicago,South Ellis Avenue, Chicago, IL 60637 (United States); Hu, Wayne [Department of Astronomy and Astrophysics, University of Chicago,South Ellis Avenue, Chicago, IL 60637 (United States); Enrico Fermi Institute and Kavli Institute for Cosmological Physics, University of Chicago,South Ellis Avenue, Chicago, IL 60637 (United States); Joyce, Austin [Enrico Fermi Institute and Kavli Institute for Cosmological Physics, University of Chicago,South Ellis Avenue, Chicago, IL 60637 (United States); Ribeiro, Raquel H. [School of Physics and Astronomy, Queen Mary University of London,Mile End Road, London, E1 4NS (United Kingdom)

    2016-06-15

    Attempts to modify gravity in the infrared typically require a screening mechanism to ensure consistency with local tests of gravity. These screening mechanisms fit into three broad classes; we investigate theories which are capable of exhibiting more than one type of screening. Specifically, we focus on a simple model which exhibits both Vainshtein and kinetic screening. We point out that due to the two characteristic length scales in the problem, the type of screening that dominates depends on the mass of the sourcing object, allowing for different phenomenology at different scales. We consider embedding this double screening phenomenology in a broader cosmological scenario and show that the simplest examples that exhibit double screening are radiatively stable.

  13. The impact of crystallization conditions on structure-based drug design: A case study on the methylene blue/acetylcholinesterase complex.

    Science.gov (United States)

    Dym, Orly; Song, Wanling; Felder, Clifford; Roth, Esther; Shnyrov, Valery; Ashani, Yacov; Xu, Yechun; Joosten, Robbie P; Weiner, Lev; Sussman, Joel L; Silman, Israel

    2016-06-01

    Structure-based drug design utilizes apoprotein or complex structures retrieved from the PDB. >57% of crystallographic PDB entries were obtained with polyethylene glycols (PEGs) as precipitant and/or as cryoprotectant, but methylene blue and decamethonium in acetylcholinesterase complexes obtained using isomorphous crystals precipitated with PEG200 or ammonium sulfate. The ligands' positions within the active-site gorge in complexes obtained using PEG200 are influenced by presence of ethyleneglycol oligomers in both cases bound to W84 at the gorge's bottom, preventing interaction of the ligand's proximal quaternary group with its indole. Consequently, both ligands are ∼3.0Å further up the gorge than in complexes obtained using crystals precipitated with ammonium sulfate, in which the quaternary groups make direct π-cation interactions with the indole. These findings have implications for structure-based drug design, since data for ligand-protein complexes with polyethylene glycol as precipitant may not reflect the ligand's position in its absence, and could result in selecting incorrect drug discovery leads. Docking methylene blue into the structure obtained with PEG200, but omitting the ethyleneglycols, yields results agreeing poorly with the crystal structure; excellent agreement is obtained if they are included. Many proteins display features in which precipitants might lodge. It will be important to investigate presence of precipitants in published crystal structures, and whether it has resulted in misinterpreting electron density maps, adversely affecting drug design. © 2016 The Protein Society.

  14. Influence of alloying and testing conditions on mechanical properties and deformation behavior of 〈100〉 tungsten-based single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Skotnicova, Katerina, E-mail: Katerina.Skotnicova@vsb.cz [VSB – Technical University of Ostrava, Faculty of Metallurgy and Materials Engineering, Department of Regional Materials Science and Technology Centre, Avenue 17 Listopadu 15, 70833 Ostrava-Poruba (Czech Republic); Kirillova, Valentina M.; Ermishkin, Vjacheslav A. [Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Leninski Prospect 49, 119991 Moscow (Russian Federation); Cegan, Tomas; Jurica, Jan; Kraus, Martin [VSB – Technical University of Ostrava, Faculty of Metallurgy and Materials Engineering, Department of Regional Materials Science and Technology Centre, Avenue 17 Listopadu 15, 70833 Ostrava-Poruba (Czech Republic); Burkhanov, Gennadij S. [Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Leninski Prospect 49, 119991 Moscow (Russian Federation)

    2015-06-11

    The results of the pressure testing of mechanical properties of single crystals of pure tungsten and low-alloyed alloys W–2Re and W–1Re–1Mo (wt%) with a crystallographic orientation 〈100〉 which were prepared by plasma-arc melting are summarized. The effect of alloying and the deformation rate on these properties have also been investigated and the fracture surfaces of the individual single crystals have been evaluated with the aid of the photometric method. The differences in the deformation behavior of pure tungsten and W–Re and W–1Mo–Re alloys were observed, which relate to the particularities of rhenium and molybdenum action in the tungsten solid solution. It can be seen from the observed results that tungsten alloying with low rhenium and molybdenum contents decreased all mechanical properties when applying the deformation rate of 0.2 mm/min. The biggest decrease was observed for the offset yield strength value. When testing with the deformation rate of 2 mm/min, the strength limit of the W–2Re alloy increased to 2013 MPa, while R{sub pt0.2} decreased by 33% in comparison with the pure tungsten single crystal. However, the ε{sub r} value remained at the same level ∼30%. In the W–1Re–1Mo single crystal, the R{sub pt0.2} and R{sub mt} values decreased, while ε{sub r} increased slightly.

  15. Kinetics of Fe3+ mineral crystallization from ferrihydrite in the presence of Si at alkaline conditions and implications for nuclear waste disposal

    DEFF Research Database (Denmark)

    Franciscco, Paul Clarence M.; Sato, Tsutomu; Otake, Tsubasa

    2016-01-01

    of the effects of Si on the surface properties of the ferrihydrite precursor. The rate constants and apparent activation energies reported in this study may be useful in estimating the crystallization behavior and timescales of Fe minerals in both natural and engineered environments. This information may...

  16. Growth of mixed K2(Ni,Co)(SO4)2·6H2O crystals under stationary conditions of supercooling and forced convection of the aqueous solution

    Science.gov (United States)

    Masalov, Vladimir M.; Vasilyeva, Natalia A.; Manomenova, Vera L.; Zhokhov, Andrei A.; Rudneva, Elena B.; Voloshin, Alexey E.; Emelchenko, Gennadi A.

    2017-10-01

    The technique and the scheme of the system for growing single crystals, including complex mixed composition, under stationary conditions of supercooling and forced convection of aqueous solution were described. Solubility in water of various compositions of K2CoxNi1-x(SO4)2·6H2O (KCNSH) and the dependence of Co content in the KCNSH crystal of Co concentration in the saline part of aqueous solutions of KCNSH have been measured in the temperature range of 30-70 °C. It was found that the growth sectors {0 0 1} and {1 1 0} differ in Ni and Co contents. The Ni/Co ratio is dependent on the value of solution supersaturation. The optical transmission spectra of crystals grown showed high transmittance in the UV region of the spectrum and the almost complete absorption of light in the visible spectrum. It is concluded that the crystals grown can be used as efficient UV filters.

  17. Preparation of Needle-like Hydroxyapatite Single Crystal by Homogeneous Precipitation Method under Hydrothermal Condition%水热条件下针状羟基磷灰石单晶体的均相合成

    Institute of Scientific and Technical Information of China (English)

    王友法; 闫玉华; 梁飞; 张宏泉

    2001-01-01

    用水热法制备出结晶度高、纯净均一的针状羟基磷灰石单晶体。从X-射线衍射谱、红外吸收光谱、透射电镜分析等方面确认了所得晶体为羟基磷灰石单晶体。根据透射电子衍射谱测量计算出的晶面间距d值与羟基磷灰石卡片的d值非常接近,由标定的晶面指数计算出的晶面夹角与实际测量值有很好的吻合,从而确定所得晶体为单晶。%The needle-like hydroxyapatite single crystals with high crystallinity were prepared by homogeneous precipitation method under hydrothermal condition.The obtained specimens were identified by XRD,SEM,IR and TEM.The inter planar distance i.e.,d value calculated from the pattem of TEM,is greatly approached to that of HA’s JCPDS card,and the angle included between the faces of crystals calculated from the marked crystal plane index is coincided with the actual measuring value,thereby it is confirmed that the specimen is single crystal.

  18. Colon cancer screening

    Science.gov (United States)

    Screening for colon cancer; Colonoscopy - screening; Sigmoidoscopy - screening; Virtual colonoscopy - screening; Fecal immunochemical test; Stool DNA test; sDNA test; Colorectal cancer - screening; Rectal ...

  19. Crystallization of lactose from carbopol gels.

    Science.gov (United States)

    Zeng, X M; Martin, G P; Marriott, C; Pritchard, J

    2000-07-01

    To crystallize lactose under static conditions with a view to preparing crystals of well-defined morphology. et-Lactose monohydrate was crystallized from neutralized Carbopol 934 gels. When the majority of crystals had grown to maturity, the gels were acidified using diluted hydrochloric acid and the crystals were harvested by filtration or centrifugation and washed with ethanol-water mixtures. Crystals prepared from the gel had a consistently narrower size distribution than control crystals, prepared from solution under constant stirring. If crystallization was effected in the gel without sedimentation of the crystals, then the resultant crystals had smooth surfaces without visually detectable surface roughness or asperities viewed by optical microscopy. The crystals from Carbopol gels also exhibited the uniform shape of an elongated tomahawk regardless of the crystallization conditions, in contrast to crystallization under constant stirring, where the crystal shape of lactose changed with crystallization conditions especially as a function of the initial concentration of lactose. All batches of lactose crystals prepared from Carbopol gels existed as alpha-lactose monohydrate, which showed better flowability than the controls of a similar particle size. Crystallization from Carbopol gel produces lactose crystals of uniform size, regular shape, smooth surface, and improved flowability.

  20. Promoting protein crystallization using a plate with simple geometry.

    Science.gov (United States)

    Chen, Rui-Qing; Yin, Da-Chuan; Liu, Yong-Ming; Lu, Qin-Qin; He, Jin; Liu, Yue

    2014-03-01

    Increasing the probability of obtaining protein crystals in crystallization screening is always an important goal for protein crystallography. In this paper, a new method called the cross-diffusion microbatch (CDM) method is presented, which aims to efficiently promote protein crystallization and increase the chance of obtaining protein crystals. In this method, a very simple crystallization plate was designed in which all crystallization droplets are in one sealed space, so that a variety of volatile components from one droplet can diffuse into any other droplet via vapour diffusion. Crystallization screening and reproducibility tests indicate that this method could be a potentially powerful technique in practical protein crystallization screening. It can help to obtain crystals with higher probability and at a lower cost, while using a simple and easy procedure.

  1. Coating Condition Evaluation and Maintenance Management of Drum Screen in A Nuclear Power Plant%国内某电站CFI系统鼓形滤网涂层状态评估及维修管理

    Institute of Scientific and Technical Information of China (English)

    李欣

    2016-01-01

    Bubbling, cracking and peeling were appeared on the coating surface of CFI system drum screen in a nuclear power plant. Analysis and evaluation of coating condition are carried out. Taking one outage of a nuclear power plant as an example,describe the process and method of defect treatment for coating repair of CFI system drum screen, which could provide reference for future on-site defect treatment.%国内某电站CFI系统鼓形滤网涂层出现严重鼓泡破损脱落现象,对涂层缺陷进行分析及评估.以电站某次大修为例,介绍该电站CFI系统鼓形滤网涂层整体修复的流程和方法,为类似设备涂层缺陷处理提供参考.

  2. A historical perspective on protein crystallization from 1840 to the present day.

    Science.gov (United States)

    Giegé, Richard

    2013-12-01

    Protein crystallization has been known since 1840 and can prove to be straightforward but, in most cases, it constitutes a real bottleneck. This stimulated the birth of the biocrystallogenesis field with both 'practical' and 'basic' science aims. In the early years of biochemistry, crystallization was a tool for the preparation of biological substances. Today, biocrystallogenesis aims to provide efficient methods for crystal fabrication and a means to optimize crystal quality for X-ray crystallography. The historical development of crystallization methods for structural biology occurred first in conjunction with that of biochemical and genetic methods for macromolecule production, then with the development of structure determination methodologies and, recently, with routine access to synchrotron X-ray sources. Previously, the identification of conditions that sustain crystal growth occurred mostly empirically but, in recent decades, this has moved progressively towards more rationality as a result of a deeper understanding of the physical chemistry of protein crystal growth and the use of idea-driven screening and high-throughput procedures. Protein and nucleic acid engineering procedures to facilitate crystallization, as well as crystallization methods in gelled-media or by counter-diffusion, represent recent important achievements, although the underlying concepts are old. The new nanotechnologies have brought a significant improvement in the practice of protein crystallization. Today, the increasing number of crystal structures deposited in the Protein Data Bank could mean that crystallization is no longer a bottleneck. This is not the case, however, because structural biology projects always become more challenging and thereby require adapted methods to enable the growth of the appropriate crystals, notably macromolecular assemblages.

  3. Couette-Taylor crystallizer: Effective control of crystal size distribution and recovery of L-lysine in cooling crystallization

    Science.gov (United States)

    Nguyen, Anh-Tuan; Yu, Taekyung; Kim, Woo-Sik

    2017-07-01

    A Couette-Taylor crystallizer is developed to enhance the L-Lysine crystal size distribution and recovery in the case of continuous cooling crystallization. When using the proposed Couette-Taylor (CT) crystallizer, the size distribution and crystal product recovery were much narrower and higher, respectively, than those from a conventional stirred tank (ST) crystallizer. Here, the coefficient of the size distribution for the crystal product from the CT crystallizer was only 0.45, while it was 0.78 in the case of the conventional ST crystallizer at an agitation speed of 700 rpm, mean residence time of 20 min, and feed concentration of 900 (g/L). Furthermore, when using the CT crystallizer, the crystal product recovery was remarkably enhanced up to 100%wt with a mean residence time of only 20 min, while it required a mean residence time of at least 60 min when using the conventional ST crystallizer. This result indicates that the CT crystallizer was much more effective than the conventional ST crystallizer in terms of controlling a narrower size distribution and achieving a 100%wt L-lysine crystal product recovery from continuous cooling crystallization. The advantage of the CT crystallizer over the conventional ST crystallizer was explained based on the higher energy dissipation of the Taylor vortex flow and larger surface area for heat transfer of the CT crystallizer. Here, the energy dissipation of the Taylor vortex flow in the CT crystallizer was 13.6 times higher than that of the random fluid motion in the conventional ST crystallizer, while the surface area per unit volume for heat transfer of the CT crystallizer was 8.0 times higher than that of the conventional ST crystallizer. As a result, the mixing condition and heat transfer of the CT crystallizer were much more effective than those of the conventional ST crystallizer for the cooling crystallization of L-lysine, thereby enhancing the L-lysine crystal size distribution and product recovery.

  4. Self-Deflection of Dark Screening Spatial Solitons Based on Higher-Order Space Charge Field

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guang-Yong; LIU Jin-Song; LIU Shi-Xiong; WANG Cheng; ZHANG Hui-Lan

    2007-01-01

    The effects of higher-order space charge field on the self-deflection of dark screening spatial solitons in biased photorefractive crystals are numerically investigated under steady-state conditions. The expression for an induced space-charge electric field including higher-order space-charge field terms is obtained. Numerical results indicate that dark solitons possess a self-deflection process during propagation, and the solitons always bend in the direction of the c axis of the crystal The self-deflection of dark solitons can experience considerable increase especially in the regime of high bias field strengths.

  5. The conditional nature of genetic interactions: the consequences of wild-type backgrounds on mutational interactions in a genome-wide modifier screen.

    Directory of Open Access Journals (Sweden)

    Sudarshan Chari

    Full Text Available The phenotypic outcome of a mutation cannot be simply mapped onto the underlying DNA variant. Instead, the phenotype is a function of the allele, the genetic background in which it occurs and the environment where the mutational effects are expressed. While the influence of genetic background on the expressivity of individual mutations is recognized, its consequences on the interactions between genes, or the genetic network they form, is largely unknown. The description of genetic networks is essential for much of biology; yet if, and how, the topologies of such networks are influenced by background is unknown. Furthermore, a comprehensive examination of the background dependent nature of genetic interactions may lead to identification of novel modifiers of biological processes. Previous work in Drosophila melanogaster demonstrated that wild-type genetic background influences the effects of an allele of scalloped (sd, with respect to both its principal consequence on wing development and its interactions with a mutation in optomotor blind. In this study we address whether the background dependence of mutational interactions is a general property of genetic systems by performing a genome wide dominant modifier screen of the sd(E3 allele in two wild-type genetic backgrounds using molecularly defined deletions. We demonstrate that ~74% of all modifiers of the sd(E3 phenotype are background-dependent due in part to differential sensitivity to genetic perturbation. These background dependent interactions include some with qualitative differences in the phenotypic outcome, as well as instances of sign epistasis. This suggests that genetic interactions are often contingent on genetic background, with flexibility in genetic networks due to segregating variation in populations. Such background dependent effects can substantially alter conclusions about how genes influence biological processes, the potential for genetic screens in alternative wild

  6. Screening CO

    NARCIS (Netherlands)

    Ramírez, A.; Hagedoorn, S.; Kramers, L.; Wildenborg, T.; Hendriks, C.

    2010-01-01

    This paper describes the development and application of a methodology to screen and rank Dutch reservoirs suitable for long-term large scale CO2 storage. The screening focuses on off- and on-shore individual aquifers, gas and oil fields. In total 176 storage reservoirs have been taken int

  7. Crystal growth and crystallography

    Science.gov (United States)

    Chernov, A. A.

    1998-01-01

    Selected topics that may be of interest for both crystal-structure and crystal-growth communities are overviewed. The growth of protein crystals, along with that of some other compounds, is one of the topics, and recent insights into related phenomena are considered as examples of applications of general principles. The relationship between crystal growth shape and structure is reviewed and an attempt to introduce semiquantitative characterization of binding for proteins is made. The concept of kinks for complex structures is briefly discussed. Even at sufficiently low supersaturations, the fluctuation of steps may not be sufficient to implement the Gibbs-Thomson law if the kink density is low enough. Subsurface ordering of liquids and growth of rough interfaces from melts is discussed. Crystals growing in microgravity from solution should be more perfect if they preferentially trap stress-inducing impurities, thus creating an impurity-depleted zone around themselves. Evidently, such a zone is developed only around the crystals growing in the absence of convection. Under terrestrial conditions, the self-purified depleted zone is destroyed by convection, the crystal traps more impurity and grows stressed. The stress relief causes mosaicity. In systems containing stress-inducing but poorly trapped impurities, the crystals grown in the absence of convection should be worse than those of their terrestrial counterparts.

  8. Assessing two-dimensional crystallization trials of small membrane proteins for structural biology studies by electron crystallography.

    Science.gov (United States)

    Johnson, Matthew C; Rudolph, Frederik; Dreaden, Tina M; Zhao, Gengxiang; Barry, Bridgette A; Schmidt-Krey, Ingeborg

    2010-10-29

    Electron crystallography has evolved as a method that can be used either alternatively or in combination with three-dimensional crystallization and X-ray crystallography to study structure-function questions of membrane proteins, as well as soluble proteins. Screening for two-dimensional (2D) crystals by transmission electron microscopy (EM) is the critical step in finding, optimizing, and selecting samples for high-resolution data collection by cryo-EM. Here we describe the fundamental steps in identifying both large and ordered, as well as small 2D arrays, that can potentially supply critical information for optimization of crystallization conditions. By working with different magnifications at the EM, data on a range of critical parameters is obtained. Lower magnification supplies valuable data on the morphology and membrane size. At higher magnifications, possible order and 2D crystal dimensions are determined. In this context, it is described how CCD cameras and online-Fourier Transforms are used at higher magnifications to assess proteoliposomes for order and size. While 2D crystals of membrane proteins are most commonly grown by reconstitution by dialysis, the screening technique is equally applicable for crystals produced with the help of monolayers, native 2D crystals, and ordered arrays of soluble proteins. In addition, the methods described here are applicable to the screening for 2D crystals of even smaller as well as larger membrane proteins, where smaller proteins require the same amount of care in identification as our examples and the lattice of larger proteins might be more easily identifiable at earlier stages of the screening.

  9. Axion Crystals

    CERN Document Server

    Ozaki, Sho

    2016-01-01

    The low-energy effective theories for gapped insulators are classified by three parameters: permittivity $\\epsilon$, permeability $\\mu$, and theta angle $\\theta$. Crystals with periodic $\\epsilon$ are known as photonic crystals. We here study the band structure of photons in a new type of crystals with periodic $\\theta$ (modulo $2\\pi$) in space, which we call the axion crystals. We find that the axion crystals have a number of new properties that the usual photonic crystals do not possess, such as the helicity-dependent photonic band gaps and the nonrelativistic gapless dispersion relation at small momentum. We briefly discuss possible realizations of axion crystals in condensed matter systems as well as high-energy physics.

  10. 晶体球中非相位匹配二次谐波产生及最佳聚焦条件%Non-Phase-Matched Second-Harmonic Generation and Optimum Focusing Condition in Crystal Sphere

    Institute of Scientific and Technical Information of China (English)

    阎江; 杨学林; 李浩文; 谢绳武; 丁良恩

    2000-01-01

    The sphere method is a newly-developed technique for mesurement of nonlinear optical coefficients in crystals. Based on the theory of aperture function of the focused Gaussian beam SHG, the non-phase-matched (NPM) SHG process in a crystal sphere is analyzed, and the optimum focus condition of type Ⅰ NPM SHG is discussed. The experiment of NPM SHG in a LiNbOa crystal sphere pumped with a pico-second laser pulse is reported. The experimental results agree well with the theoretical prediction.%晶体球法是近年来在国际上发展起来的一种测量非线性系数的新方法。根据聚焦高斯光束二次谐波产生的孔径方程理论,分析了晶体球中的第1类非相位匹配二次谐波产生过程,讨论了晶体球中第1类非相位匹配二次谐波最佳聚焦参数的选择。报道了LiNbo3晶体球中皮秒激光脉冲抽运的非相位匹配二次谐波实验。所得结果与理论预计相符。

  11. 第三类热边界条件对激光晶体热效应的影响%Influence of the Third Thermal Boundary Condition on the Thermal Effect of Laser Crystal

    Institute of Scientific and Technical Information of China (English)

    史彭; 常锐; 陈文; 李隆; 甘安生; 李金平

    2009-01-01

    Based on the analytical theory of aeolotropy,thermal distortion and temperature field distributions of Nd : YVO_4 crystal with rectangular section were investigated when the third thermal boundary condition was considerated. By analyzing the working characteristics of the Nd:YVO_4 laser crystal,a thermal model that accords with the working state of the laser crystal was established. Using a kind of new solution to sovle the heat conduction equation of the anisotropic medium, general solution expressions of the temperature field and the thermal distortion field of Nd :YVO_4 crystal with rectangular section were obtained. The results show that a maximum temperature rise of 499. 5K and a maximum thermal distortion of 0. 99 μm can be obtained in the center of the pump face when the Nd : YVO_4 laser crystal is pumped by a Diode Laser with a output power of 15 Watt from the center of end face (the weight percent of neodymium ion doped in the crystal equals 0. 5% ). This method is more accurate compared with those in which the third thermal boundary condition is approximatively regarded as the second thermal boundary condition. And this method can also be applied to the research on the other thermal problems of laser crystal and offer theoretical basis for effectively solving the thermal problems in laser system.%以各向异性半解析热分析理论为基础,研究矩形横截面Nd:YVO_4激光晶体在有第三类热边界条件工作时,激光晶体温度场分布和晶体抽运面热形变分布.通过激光晶体工作特点分析,建立符合激光晶体工作状态的热模型.利用各向异性介质热传导方程的半解析求解方法,得出了矩形截面Nd:YVO_4晶体的温度场、端面热形变场的通解表达式.研究结果表明:当使用输出功率为15 W半导体激光器端面中心入射Nd:YVO_4晶体(晶体掺钕离子质量分数为0.5%)时,在抽运端面中心获得499.5 K最高温度和0.99 μm最大热形变量.和将第三类热边界

  12. A robust and scalable microfluidic metering method that allows protein crystal growth by free interface diffusion

    OpenAIRE

    Hansen, Carl L.; Skordalakes, Emmanuel; Berger, James M.; Quake, Stephen R.

    2002-01-01

    Producing robust and scalable fluid metering in a microfluidic device is a challenging problem. We developed a scheme for metering fluids on the picoliter scale that is scalable to highly integrated parallel architectures and is independent of the properties of the working fluid. We demonstrated the power of this method by fabricating and testing a microfluidic chip for rapid screening of protein crystallization conditions, a major hurdle in structural biology efforts. The chip has 480 active...

  13. Quadruple screen test

    Science.gov (United States)

    Quad screen; Multiple marker screening; AFP plus; Triple screen test; AFP maternal; MSAFP; 4-marker screen; Down syndrome - quadruple; Trisomy 21 - quadruple; Turner syndrome - quadruple; Spina bifida - ...

  14. Toxicology screen

    Science.gov (United States)

    Toxicology screening is most often done using a blood or urine sample. However, it may be done soon after the person swallowed the medication, using stomach contents taken through gastric lavage (stomach pumping) or after vomiting.

  15. Hypertension screening

    Science.gov (United States)

    Foulke, J. M.

    1975-01-01

    An attempt was made to measure the response to an announcement of hypertension screening at the Goddard Space Center, to compare the results to those of previous statistics. Education and patient awareness of the problem were stressed.

  16. Hypertension screening

    Science.gov (United States)

    Foulke, J. M.

    1975-01-01

    An attempt was made to measure the response to an announcement of hypertension screening at the Goddard Space Center, to compare the results to those of previous statistics. Education and patient awareness of the problem were stressed.

  17. Phoenito experiments: combining the strengths of commercial crystallization automation.

    Science.gov (United States)

    Newman, Janet; Pham, Tam M; Peat, Thomas S

    2008-11-01

    The use of crystallization robots for initial screening in macromolecular crystallization is well established. This paper describes how four general optimization techniques, growth-rate modulation, fine screening, seeding and additive screening, have been adapted for automation in a medium-throughput crystallization service facility. The use of automation for more challenging optimization experiments is discussed, as is a novel way of using both the Mosquito and the Phoenix nano-dispensing robots during the setup of a single crystallization plate. This dual-dispenser technique plays to the strengths of both machines.

  18. 磨盘柿脱涩优化条件筛选%Screen the de-astringent optimal condition of Mopan persimmon

    Institute of Scientific and Technical Information of China (English)

    张鹏; 李江阔; 陈绍慧; 张平; 周志江

    2012-01-01

    In order to explore the optimal de-astringent condition of Mopan persimmon, the optimal condition of CO2 complete de-astringency, CO2 two segment de-astringency and vacuum packaging de- astringency were studied by orthogonal test. The result showed that C02 complete de-astringent condition was ambient temperature of 25 ℃, CO2 concentration of 90% and de-astringent time of 24 h, CO2 de- astringent of two stage method was ambient temperature from 18 ℃ to 20 %, packaging of plastic net andplacement 24 h after 90% CO2 de-astringent 24 h, and vacuum packaging de-astringent condition was ambient temperature from 18 % to 20 %, vacuum degree of 0.08 MPa and de-astringent time of 10 d.%为了探讨磨盘柿最佳的脱涩条件,通过正交试验对CO2全脱涩、CO2二段法脱涩和真空包装脱涩条件进行优化。结果表明,CO2全脱涩条件:环境温度为25℃、CO2浓度为90%、脱涩时间24h;CO2二段法脱涩条件:环境温度为18-20℃、网套包装、90%CO2脱涩24h后再放置24h;真空包装脱涩条件:环境温度为18~20℃、真空度0.08MPa、脱涩时间10d。

  19. Quartz crystal growth

    Science.gov (United States)

    Baughman, Richard J.

    1992-01-01

    A process for growing single crystals from an amorphous substance that can undergo phase transformation to the crystalline state in an appropriate solvent. The process is carried out in an autoclave having a lower dissolution zone and an upper crystallization zone between which a temperature differential (.DELTA.T) is maintained at all times. The apparatus loaded with the substance, solvent, and seed crystals is heated slowly maintaining a very low .DELTA.T between the warmer lower zone and cooler upper zone until the amorphous substance is transformed to the crystalline state in the lower zone. The heating rate is then increased to maintain a large .DELTA.T sufficient to increase material transport between the zones and rapid crystallization. .alpha.-Quartz single crystal can thus be made from fused quartz in caustic solvent by heating to 350.degree. C. stepwise with a .DELTA.T of 0.25.degree.-3.degree. C., increasing the .DELTA.T to about 50.degree. C. after the fused quartz has crystallized, and maintaining these conditions until crystal growth in the upper zone is completed.

  20. RNA Crystallization

    Science.gov (United States)

    Golden, Barbara L.; Kundrot, Craig E.

    2003-01-01

    RNA molecules may be crystallized using variations of the methods developed for protein crystallography. As the technology has become available to syntheisize and purify RNA molecules in the quantities and with the quality that is required for crystallography, the field of RNA structure has exploded. The first consideration when crystallizing an RNA is the sequence, which may be varied in a rational way to enhance crystallizability or prevent formation of alternate structures. Once a sequence has been designed, the RNA may be synthesized chemically by solid-state synthesis, or it may be produced enzymatically using RNA polymerase and an appropriate DNA template. Purification of milligram quantities of RNA can be accomplished by HPLC or gel electrophoresis. As with proteins, crystallization of RNA is usually accomplished by vapor diffusion techniques. There are several considerations that are either unique to RNA crystallization or more important for RNA crystallization. Techniques for design, synthesis, purification, and crystallization of RNAs will be reviewed here.

  1. Crystallization Behavior and Growing Process of Rutile Crystals in Ti-Bearing Blast Furnace Slag

    Science.gov (United States)

    Zhang, Wu; Zhang, Li; Li, Yuhai; Li, Xin

    2016-09-01

    The aim of the present work is to elucidate crystallization and growing process of rutile crystals in Ti-bearing blast furnace slag. The samples were taken from the liquid slag and quenched at once at elevated temperatures in order to analyze phase transaction of titanium and grain size of rutile crystals. Crystallization and growing kinetics of rutile crystals under elevated temperature conditions were calculated, and the crystallization process of rutile crystals under isothermal conditions was expressed by Avrami equation. The effects of experimental parameters, such as experimental temperatures, SiO2 addition, cooling rate, crystal seed addition and oxygen flow, were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), the optimal conditions for rutile crystals to grow up were obtained. Distribution and movement state of rutile crystals in the slag were analyzed.

  2. Protein Crystallization

    Science.gov (United States)

    Chernov, Alexander A.

    2005-01-01

    Nucleation, growth and perfection of protein crystals will be overviewed along with crystal mechanical properties. The knowledge is based on experiments using optical and force crystals behave similar to inorganic crystals, though with a difference in orders of magnitude in growing parameters. For example, the low incorporation rate of large biomolecules requires up to 100 times larger supersaturation to grow protein, rather than inorganic crystals. Nucleation is often poorly reproducible, partly because of turbulence accompanying the mixing of precipitant with protein solution. Light scattering reveals fluctuations of molecular cluster size, its growth, surface energies and increased clustering as protein ages. Growth most often occurs layer-by-layer resulting in faceted crystals. New molecular layer on crystal face is terminated by a step where molecular incorporation occurs. Quantitative data on the incorporation rate will be discussed. Rounded crystals with molecularly disordered interfaces will be explained. Defects in crystals compromise the x-ray diffraction resolution crucially needed to find the 3D atomic structure of biomolecules. The defects are immobile so that birth defects stay forever. All lattice defects known for inorganics are revealed in protein crystals. Contribution of molecular conformations to lattice disorder is important, but not studied. This contribution may be enhanced by stress field from other defects. Homologous impurities (e.g., dimers, acetylated molecules) are trapped more willingly by a growing crystal than foreign protein impurities. The trapped impurities induce internal stress eliminated in crystals exceeding a critical size (part of mni for ferritin, lysozyme). Lesser impurities are trapped from stagnant, as compared to the flowing, solution. Freezing may induce much more defects unless quickly amorphysizing intracrystalline water.

  3. Crystallization and crystal manipulation of the Pterocarpus angolensis seed lectin.

    Science.gov (United States)

    Loris, Remy; Garcia-Pino, Abel; Buts, Lieven; Bouckaert, Julie; Beeckmans, Sonia; De Greve, Henri; Wyns, Lode

    2005-06-01

    The Man/Glc-specific legume lectin from the seeds of the African bloodwood tree (Pterocarpus angolensis) was crystallized in the presence of the disaccharide ligand Man(alpha1-3)ManMe. Small crystals initially appeared from a preliminary screen, but proved difficult to reproduce. The initial crystals were used to prepare microseeds, leading to a reproducible crystallization protocol. All attempts to obtain crystals directly of the ligand-free protein or of other carbohydrate complexes failed. However, the Man(alpha1-3)ManMe co-crystals withstand soaking with ten other carbohydrates known to bind to the lectin. Soaking for 15 min in 100 mM carbohydrate typically resulted in complete replacement of Man(alpha1-3)ManMe by the desired carbohydrate despite the involvement of lattice contacts at the binding site. Transferring the crystals for two weeks in carbohydrate-free artificial mother liquor resulted in the complete removal of the sugar from one of the two monomers in the asymmetric unit. Additional treatment of these crystals with 100 mM EDTA for two weeks resulted in removal of the structural calcium and manganese ions, which is accompanied by significant structural rearrangements of the loops that constitute the carbohydrate-binding site.

  4. Real condition high throughput screening of Cu/ZnO/Al{sub 2}O{sub 3}. Catalysts for methanol synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Baltes, C.; Vukojevic, S.; Schueth, F. [Max-Planck-Institut fuer Kohlenforschung, Muehlheim an der Ruhr (Germany)

    2006-07-01

    Ternary Cu/ZnO/Al{sub 2}O{sub 3} catalysts were systematically prepared via the co-precipitation route under strict control of parameters such as pH, precipitation temperature and calcination temperature. All catalysts were tested with respect to their methanol activity in a 49-fold multitubular high-throughput experimentation setup under conditions similar to the commercial methanol production route, using a syngas mixture of CO, CO{sub 2} and H{sub 2}. Statistically representative catalysts were chosen for more detailed structure and morphology analysis in order to study correlations between the catalyst ''preparation history'' and the methanol productivity. The highest catalyst performance was observed for catalysts obtained in the pH range from 6 to 8 at 70 C. XRD measurements allowed the ''grouping'' of catalysts based on their composition. It was found that a group of best-performance catalysts exhibited the characteristic XRD pattern of non-calcined Cu/Zn hydroxycarbonate residues, leading to the assumption that carbonate species in the final catalyst structure may enhance its productivity. Further investigations of these hydroxycarbonate containing catalysts gave more detailed insights into the dynamic aging process and its influence on the catalytic performance. Highest methanol activity was observed for catalysts aged between 20 and 60 minutes after an initial phase formation time. The optimum calcination temperature was found to be in the range from 250 to 300 C. Under these conditions the resulting Cu/Zn/Al hydroxycarbonates remained stable. Additionally, the syngas feed composition was varied under reaction conditions and correlated to catalytic activities. Highest methanol productivity over Cu/ZnO/Al{sub 2}O{sub 3} catalysts was observed for the following gas concentrations; H{sub 2}: 50-60 %, CO: 30-40 % and CO{sub 2}: 5-10 % at 4.5 MPa and 245 C. (orig.)

  5. Shaped Crystal Growth

    Science.gov (United States)

    Tatartchenko, Vitali A.

    Crystals of specified shape and size (shaped crystals) with controlled crystal growth (SCG) defect and impurity structure have to be grown for the successful development of modern engineering. Since the 1950s many hundreds of papers and patents concerned with shaped growth have been published. In this chapter, we do not try to enumerate the successful applications of shaped growth to different materials but rather to carry out a fundamental physical and mathematical analysis of shaping as well as the peculiarities of shaped crystal structures. Four main techniques, based on which the lateral surface can be shaped without contact with the container walls, are analyzed: the Czochralski technique (CZT), the Verneuil technique (VT), the floating zone technique (FZT), and technique of pulling from shaper (TPS). Modifications of these techniques are analyzed as well. In all these techniques the shape of the melt meniscus is controlled by surface tension forces, i.e., capillary forces, and here they are classified as capillary shaping techniques (CST). We look for conditions under which the crystal growth process in each CST is dynamically stable. Only in this case are all perturbations attenuated and a crystal of constant cross section shaping technique (CST) grown without any special regulation. The dynamic stability theory of the crystal growth process for all CST is developed on the basis of Lyapunov's dynamic stability theory. Lyapunov's equations for the crystal growth processes follow from fundamental laws. The results of the theory allow the choice of stable regimes for crystal growth by all CST as well as special designs of shapers in TPS. SCG experiments by CZT, VT, and FZT are discussed but the main consideration is given to TPS. Shapers not only allow crystal of very complicated cross section to be grown but provide a special distribution of impurities. A history of TPS is provided later in the chapter, because it can only be described after explanation of the

  6. HCC screening; HCC-Screening

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, T. [Charite-Unversitaetsmedizin,Freie Universitaet und Humboldt-Universitaet zu Berlin, Klinik und Hochschulambulanz fuer Radiologie und Nuklearmedizin,Campus Benjamin Franklin, Berlin (Germany)

    2008-01-15

    Hepatocellular carcinoma (HCC) is one of the most frequently diagnosed tumour diseases throughout the world. In the vast majority of cases those affected are high-risk patients with chronic viral hepatitis and/or liver cirrhosis, which means there is a clearly identifiable target group for HCC screening. With resection, transplantation, and interventional procedures for local ablation, following early diagnosis curative treatment options are available with which 5-year survival rates of over 60% can be reached. Such early diagnosis is a reality only in a minority of patients, however, and in the majority of cases the disease is already in an advanced stage at diagnosis. One of the objects of HCC screening is diagnosis in an early stage when curative treatment is still possible. Precisely this is achieved by screening, so that the proportion of patients treated with curative intent is decisively higher. There is not yet any clear evidence as to whether this leads to a lowering of the mortality of HCC. As lower mortality is the decisive indicator of success for a screening programme the benefit of HCC screening has so far been neither documented nor refuted. Nonetheless, in large regions of the world it is the practice for high-risk patients to undergo HCC screening in the form of twice-yearly ultrasound examination and determination of AFP. (orig.) [German] Das hepatozellulaere Karzinom (HCC) ist eine der weltweit haeufigsten Tumorerkrankungen. Es tritt in der grossen Mehrzahl der Faelle bei Hochrisikopatienten mit chronischer Virushepatitis bzw. Leberzirrhose auf, woraus sich eine klar identifizierbare Zielgruppe fuer das HCC-Screening ergibt. Mit der Resektion, der Transplantation und interventionellen lokal ablativen Verfahren stehen bei rechtzeitiger Diagnosestellung kurative Therapieoptionen zur Verfuegung, die 5-Jahres-Ueberlebensraten von >60% erreichen. Diese rechtzeitige Diagnosestellung erfolgt jedoch nur bei einer Minderzahl der Patienten, waehrend die

  7. Pancreatic Cancer Screening.

    Science.gov (United States)

    Das, Koushik K; Early, Dayna

    2017-09-06

    This review describes the rationale for pancreatic cancer screening, outlines groups that are at elevated risk for pancreatic cancer, and summarizes the relative risk in each setting. We also review the methods available for performing pancreatic cancer screening and the recommended screening intervals. Several genetic mutations have been identified that increase the risk for pancreatic cancer. Most are rare, however, and at-risk individuals are most often those with a strong family history of pancreatic cancer (with multiple family members affected) but no identifiable genetic mutation. Known genetic syndromes that increase the risk for pancreatic cancer include hereditary pancreatitis, familial atypical mole and multiple melanoma, Peutz-Jeghers syndrome, Lynch syndrome, BRCA mutations, and Li-Fraumeni syndrome. Genetic testing should be performed in conjunction with genetic counseling, and testing of an affected family member is preferred if possible.The goal of pancreatic cancer screening is to identify pancreatic cancer at an early, curable stage or, ideally, to identify precancerous lesions that can be resected to prevent the development of cancer. Imaging can be performed with either endoscopic ultrasound (EUS) or magnetic resonance cholangiopancreatography (MRCP). These techniques are generally considered to be complementary, although an advantage of EUS is that cysts or solid lesions can be sampled at the time of the procedure. Published results of small cohorts of high-risk patients in pancreatic cancer screening programs have demonstrated a high prevalence of small cystic lesions identified on EUS or MRCP, which often represent side-branch intraductal papillary mucinous neoplasms (IPMN). Knowledge of conditions and syndromes that increase pancreatic cancer risk allows one to identify those patients that may benefit from pancreatic cancer screening. As we gather evidence from large, international, multicenter cohorts of patients at high-risk for pancreatic

  8. Quick Screening of Pareto-Optimal Operating Conditions for Expanding Solvent–Steam Assisted Gravity Drainage Using Hybrid Multi-Objective Optimization Approach

    Directory of Open Access Journals (Sweden)

    Baehyun Min

    2017-07-01

    Full Text Available Solvent–steam mixture is a key factor in controlling the economic efficiency of the solvent-aided thermal injection process for producing bitumen in a highly viscous oil sands reservoir. This paper depicts a strategy to quickly provide trade-off operating conditions of the Expanding Solvent–Steam Assisted Gravity Drainage (ES-SAGD process based on Pareto-optimality. Response surface models are employed to evaluate multiple ES-SAGD scenarios at low computational costs. The surrogate models play a role of objective-estimators in the multi-objective optimization that provides qualified ES-SAGD scenarios regarding bitumen recovery, steam–energy efficiency, and solvent-energy efficiency. The developed hybrid approach detects positive or negative correlations among the performance indicators of the ES-SAGD process. The derived Pareto-optimal operating conditions give flexibility in field development planning and thereby help decision makers determine the operating parameters of the ES-SAGD process based on their preferences.

  9. Quantitative and qualitative optimization of allergen extraction from peanut and selected tree nuts. Part 1. Screening of optimal extraction conditions using a D-optimal experimental design.

    Science.gov (United States)

    L'Hocine, Lamia; Pitre, Mélanie

    2016-03-01

    A D-optimal design was constructed to optimize allergen extraction efficiency simultaneously from roasted, non-roasted, defatted, and non-defatted almond, hazelnut, peanut, and pistachio flours using three non-denaturing aqueous (phosphate, borate, and carbonate) buffers at various conditions of ionic strength, buffer-to-protein ratio, extraction temperature, and extraction duration. Statistical analysis showed that roasting and non-defatting significantly lowered protein recovery for all nuts. Increasing the temperature and the buffer-to-protein ratio during extraction significantly increased protein recovery, whereas increasing the extraction time had no significant impact. The impact of the three buffers on protein recovery varied significantly among the nuts. Depending on the extraction conditions, protein recovery varied from 19% to 95% for peanut, 31% to 73% for almond, 17% to 64% for pistachio, and 27% to 88% for hazelnut. A modulation by the buffer type and ionic strength of protein and immunoglobuline E binding profiles of extracts was evidenced, where high protein recovery levels did not always correlate with high immunoreactivity.

  10. Recovery of indium from LCD screens of discarded cell phones.

    Science.gov (United States)

    Silveira, A V M; Fuchs, M S; Pinheiro, D K; Tanabe, E H; Bertuol, D A

    2015-11-01

    Advances in technological development have resulted in high consumption of electrical and electronic equipment (EEE), amongst which are cell phones, which have LCD (liquid crystal display) screens as one of their main components. These multilayer screens are composed of different materials, some with high added value, as in the case of the indium present in the form of indium tin oxide (ITO, or tin-doped indium oxide). Indium is a precious metal with relatively limited natural reserves (Dodbida et al., 2012), so it can be profitable to recover it from discarded LCD screens. The objective of this study was to develop a complete process for recovering indium from LCD screens. Firstly, the screens were manually removed from cell phones. In the next step, a pretreatment was developed for removal of the polarizing film from the glass of the LCD panels, because the adherence of this film to the glass complicated the comminution process. The choice of mill was based on tests using different equipment (knife mill, hammer mill, and ball mill) to disintegrate the LCD screens, either before or after removal of the polarizing film. In the leaching process, it was possible to extract 96.4 wt.% of the indium under the following conditions: 1.0M H2SO4, 1:50 solid/liquid ratio, 90°C, 1h, and stirring at 500 rpm. The results showed that the best experimental conditions enabled extraction of 613 mg of indium/kg of LCD powder. Finally, precipitation of the indium with NH4OH was tested at different pH values, and 99.8 wt.% precipitation was achieved at pH 7.4.

  11. Laboratory screening of potential predators of the poultry red mite (Dermanyssus gallinae) and assessment of Hypoaspis miles performance under varying biotic and abiotic conditions.

    Science.gov (United States)

    Ali, W; George, D R; Shiel, R S; Sparagano, O A E; Guy, J H

    2012-06-08

    The poultry red mite, Dermanyssus gallinae (De Geer), is the most important ectoparasitic pest of layer hens worldwide and difficult to control through 'conventional' synthetic acaricides. The present study aimed to identify a suitable predator of D. gallinae that could potentially form the basis of biological control in commercial poultry systems. From four selected predatory mite species (Hypoaspis miles (Berlese), Hypoaspis aculeifer (Canestrini), Amblyseius degenerans (Berlese) and Phytoseiulus persimilis (Athias-Henriot)), Hypoaspis mites demonstrated the greatest potential as predators of D. gallinae. Experiments were also conducted to assess the effect of environmental (temperature and dust), physical (presence of harbourages) and biological (presence of alternative prey) factors on the predatory efficacy of H. miles. Predation of D. gallinae per se was observed under all conditions tested, though was found to be temperature-dependent and reduced by the presence of alternative prey.

  12. Crystal Data

    Science.gov (United States)

    SRD 3 NIST Crystal Data (PC database for purchase)   NIST Crystal Data contains chemical, physical, and crystallographic information useful to characterize more than 237,671 inorganic and organic crystalline materials. The data include the standard cell parameters, cell volume, space group number and symbol, calculated density, chemical formula, chemical name, and classification by chemical type.

  13. Development and use of a new burner rig facility to mimic service loading conditions of Ni-based single crystal superalloys

    Directory of Open Access Journals (Sweden)

    Mauget Florent

    2014-01-01

    Full Text Available Performing representative experiments of in-service operating conditions of Ni-based superalloys used as high pressure turbine blades in aeroengines is a challenging issue due to the complex environmental, mechanical and thermal solicitations encountered by those components. A new burner rig test facility called MAATRE (French acronym for Mechanics and Aerothermics of Cooled Turbine Blades has been developed at ENSMA – Pprime Institute to mimic as close as possible those operating conditions. This new test bench has been used to perform complex non-isothermal creep tests representative of thermomechanical solicitations seen by some sections of HP turbine blades during engine certification procedure.

  14. Esophageal Cancer Screening

    Science.gov (United States)

    ... Esophageal Cancer Prevention Esophageal Cancer Screening Research Esophageal Cancer Screening (PDQ®)–Patient Version What is screening? Go to ... the esophagus and the stomach). Being overweight . Esophageal Cancer Screening Key Points Tests are used to screen for ...

  15. Czochralski crystal growth: Modeling study

    Science.gov (United States)

    Dudukovic, M. P.; Ramachandran, P. A.; Srivastava, R. K.; Dorsey, D.

    1986-01-01

    The modeling study of Czochralski (Cz) crystal growth is reported. The approach was to relate in a quantitative manner, using models based on first priniciples, crystal quality to operating conditions and geometric variables. The finite element method is used for all calculations.

  16. A "core-top" screen for trace element proxies of environmental conditions and growth rates in the calcite skeletons of bamboo corals (Isididae)

    Science.gov (United States)

    Thresher, Ronald E.; Fallon, Stewart J.; Townsend, Ashley T.

    2016-11-01

    We test for trace element proxies in the high-magnesium calcite fraction of bamboo coral internodes by comparing environmental conditions and growth rates to the specimen-mean compositions of 73 corals that were live-caught at depths ranging from 3 to 3950 m and collected from habitats ranging from tropical coral reefs to the Antarctic slope. Comparisons were done at a large geographic scale (LGS) and for a well sampled area south of Australia, across depths at a single site, in order to help separate the effects of environmental variables that co-vary at one spatial scale, but not the other. Thirty-seven trace elements were measured using solution-based Sector Field ICP-MS, of which seventeen were significantly detected in more than a third of the specimens. Only eight element/calcium ratios correlated significantly with any environmental variable at the large geographic scale, and only four did so at the local level. At the LGS, the highest correlation was between ambient temperature and Mg/Ca, which accounted for 89% of the variance across specimens, spanned all four Isidid sub-families and was independently significant in the two best sampled sub-families.

  17. Batch crystallization of rhodopsin for structural dynamics using an X-ray free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wenting; Nogly, Przemyslaw; Rheinberger, Jan; Kick, Leonhard M.; Gati, Cornelius; Nelson, Garrett; Deupi, Xavier; Standfuss, Jörg; Schertler, Gebhard; Panneels, Valérie, E-mail: valerie.panneels@psi.ch [Paul Scherrer Institute, OFLC/103, 5232 Villigen-PSI (Switzerland)

    2015-06-27

    A new batch preparation method is presented for high-density micrometre-sized crystals of the G protein-coupled receptor rhodopsin for use in time-resolved serial femtosecond crystallography at an X-ray free-electron laser using a liquid jet. Rhodopsin is a membrane protein from the G protein-coupled receptor family. Together with its ligand retinal, it forms the visual pigment responsible for night vision. In order to perform ultrafast dynamics studies, a time-resolved serial femtosecond crystallography method is required owing to the nonreversible activation of rhodopsin. In such an approach, microcrystals in suspension are delivered into the X-ray pulses of an X-ray free-electron laser (XFEL) after a precise photoactivation delay. Here, a millilitre batch production of high-density microcrystals was developed by four methodical conversion steps starting from known vapour-diffusion crystallization protocols: (i) screening the low-salt crystallization conditions preferred for serial crystallography by vapour diffusion, (ii) optimization of batch crystallization, (iii) testing the crystal size and quality using second-harmonic generation (SHG) imaging and X-ray powder diffraction and (iv) production of millilitres of rhodopsin crystal suspension in batches for serial crystallography tests; these crystals diffracted at an XFEL at the Linac Coherent Light Source using a liquid-jet setup.

  18. Investigating electro-optical properties of a nematic liquid crystal cell with planar anchoring boundary condition for various thicknesses: A Monte Carlo study

    Science.gov (United States)

    Emül, Yakup; Polat, Ömer; San, Sait Eren; Kayacan, Özhan; Özbek, Haluk

    2014-06-01

    Monte Carlo (MC) simulations and the Mueller matrix formalism were applied to investigate electro optical properties of a LC cell with planar boundary conditions for various thicknesses. Field dependent global order parameter and the optical transmissions were analyzed in common. Three characteristic regions of the periodicity of optical transmissions as a function of polarizer angle and the external field were identified.

  19. 三亚地区农村妇女宫颈癌认知度和筛查状况分析%Analysis of cervical cancer awareness and screening situationcervical cancer awareness and screening condition of of rural married women in the rural areas of Sanya

    Institute of Scientific and Technical Information of China (English)

    王瑛; 李丽霞; 张亲凤; 李凤玉; 林燕玲; 曾祥丽

    2013-01-01

    目的 了解三亚地区农村妇女宫颈癌的认知度和筛查状况,并分析二者之间的关系.方法 用随机整群抽样的方法选择三亚辖区内两个乡镇的农村已婚妇女为调查对象,研究宫颈癌的认知和筛查水平,Pearson 直线相关分析确定二者之间的相关性.结果 共发放问卷2 650 份,回收2 355 份有效问卷,回收率为88.87%;31.93%和19.75%的调查对象能正确的认识人类乳头状瘤病毒(HPV)和宫颈癌筛查,23.86%、19.62%和4.33%的调查对象在1 年内、1~3年和3 年以前接受过宫颈癌筛查,52.2%的调查对象从未接受过宫颈癌筛查,宫颈癌认知和筛查水平之间存在相关性(r=0.681,P<0.05).结论 三亚地区农村妇女宫颈癌认知和筛查水平均较低,应加大宫颈癌筛查的宣传力度,提高妇女对宫颈癌的认知和筛查水平.%Objective To study the cervical cancer awareness and screening situation of married women in the rural areas of Sanya, and to investigate the relationship between them. Methods Questionnaires were distributed in married women in rural areas of Sanya. The general information, awareness of cervical cancer and screening situation were recorded and analyzed. Results A total of 2 650 questionnaires were distributed, and 2 355 (88.87%) were retrieved. 31.93% and 19.75% of the subjects got correct awareness of human papillomavirus and cervical cancer screening, respectively. 23.86%, 19.62% and 4.33% of the subjects received cervical cancer screening within the previous 1 year, the previous 1~3 years, and 3 years ago, respectively, while 52.2% never received cervical cancer screening. There was significant correlation between the awareness of cervical cancer and screening rates of cervical cancer. Conclusion The awareness and screening rates of cervical cancer are low in the rural areas of Sanya, publicity and education must be taken to improve the current condition.

  20. Macromolecular crystallization and crystal perfection

    CERN Document Server

    Chayen, Naomi E; Snell, Edward H

    2010-01-01

    Structural biology is key to our understanding of the mechanisms of biological processes. This text describes current methods and future frontiers in crystal growth and use of X-ray and neutron crystallography, in the context of automation of crystallization and generation of synchrotron X-ray and neutron beams.

  1. Additive manufacturing of micrometric crystallization vessels and single crystals

    Science.gov (United States)

    Halevi, Oded; Jiang, Hui; Kloc, Christian; Magdassi, Shlomo

    2016-11-01

    We present an all-additive manufacturing method that is performed at mild conditions, for the formation of organic single crystals at specific locations, without any photolithography prefabrication process. The method is composed of two steps; inkjet printing of a confinement frame, composed of a water soluble electrolyte. Then, an organic semiconductor solution is printed within the confinement to form a nucleus at a specific location, followed by additional printing, which led to the growth of a single crystal. The specific geometry of the confinement enables control of the specific locations of the single crystals, while separating the nucleation and crystal growth processes. By this method, we printed single crystals of perylene, which are suitable for the formation of OFETs. Moreover, since this method is based on a simple and controllable wet deposition process, it enables formation of arrays of single crystals at specific locations, which is a prerequisite for mass production of active organic elements on flexible substrates.

  2. Crystallization and Polymorphism of Felodipine

    DEFF Research Database (Denmark)

    Surov, A. O.; Solanko, K. A.; Bond, A. D.

    2012-01-01

    . The crystal structures of the new forms III and IV were determined using single-crystal X-ray diffraction. Forms I, II, and III were obtained in bulk form and characterized by a variety of analytical methods, including thermal analysis, solution calorimetry, intrinsic dissolution rate measurement......, and solubility measurement. Form IV could be obtained only as a few isolated single crystals, and its crystallization could not be reproduced. On the basis of the measured thermochemical data and solubility studies, form I appears to be the thermodynamically most stable phase at ambient conditions, although...

  3. SCREEN CUISINE

    National Research Council Canada - National Science Library

    Heather Baysa

    2010-01-01

    ... from the legendary restaurant; the World's First FoodTruck Drive-In Movie on Saturday, where the city's finest food-truck vendors park for the screenings; and the Brooklyn Burger W Beer Garden on Sunday, serving up hearty burgers and brews while you watch Anat Baron's Beer Wars. Tonight at 7, Water Taxi Beach, South Street Seaport.fest...

  4. Airport Screening

    Science.gov (United States)

    ... must be limited to a safe level. An American National Standards Institute/Health Physics Society industry standard states that the maxi- mum ... that does not directly damage DNA. 2 References American National ... Physics Society. Radiation safety for personnel security screening systems ...

  5. Liquid crystal tunable photonic crystal dye laser

    DEFF Research Database (Denmark)

    Buss, Thomas; Christiansen, Mads Brøkner; Smith, Cameron

    2010-01-01

    We present a dye-doped liquid crystal laser using a photonic crystal cavity. An applied electric field to the liquid crystal provides wavelength tunability. The photonic crystal enhances resonant interaction with the gain medium....

  6. Optical Resolution of DL-Tartaric Acid Mediated by Diastereomeric Salts Crystallization: A Useful Method for Exploring and Optimizing Experimental Conditions

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A response surface modeling approach for simultaneous optimization of optical purity and yield wasapplied to the resolution of tartaric acid to study the effects of both the amount of the solvent and the amountof the resolving agent α-methylbenzyl amine on the resolution results. The direction of changing the experimen-tal conditions was determined from the initial response study, and expected high yield of the pure L(+)-tartaricacid-L(-)-α-methylbenzyl amine salt was obtained.

  7. Analytical solutions for anisotropic time-dependent heat equations with Robin boundary condition for cubic-shaped solid-state laser crystals.

    Science.gov (United States)

    Sabaeian, Mohammad

    2012-10-20

    The problem of finding analytical solutions for time-dependent or time-independent heat equations, especially for solid-state laser media, has required a lot of work in the field of thermal effects. However, to calculate the temperature distributions analytically, researchers often have to make some approximations or employ complex methods. In this work, we present full analytical solutions for anisotropic time-dependent heat equations in the Cartesian coordinates with various source terms corresponding to various pumping schemes. Moreover, the most general boundary condition of Robin (or impedance boundary condition), corresponding to the convection cooling mechanism, was applied. This general condition can be easily switched to constant temperature and thermal insulation as special cases. To this end, we first proposed a general approach to solving time-dependent heat equations with an arbitrary heat source. We then applied our approach to explore the temperature distribution for three cases: steady-state pumping or long transient, single-shot pumping or short transient, and repetitively pulsed pumping. Our results show the possibility of an easier and more accurate approach to analytical calculations of the thermal dispersion, thermal stresses (strains), thermal bending, thermal phase shift, and other thermal effects.

  8. Crystal Dislocations

    Directory of Open Access Journals (Sweden)

    Ronald W. Armstrong

    2016-01-01

    Full Text Available Crystal dislocations were invisible until the mid-20th century although their presence had been inferred; the atomic and molecular scale dimensions had prevented earlier discovery. Now they are normally known to be just about everywhere, for example, in the softest molecularly-bonded crystals as well as within the hardest covalently-bonded diamonds. The advent of advanced techniques of atomic-scale probing has facilitated modern observations of dislocations in every crystal structure-type, particularly by X-ray diffraction topography and transmission electron microscopy. The present Special Issue provides a flavor of their ubiquitous presences, their characterizations and, especially, their influence on mechanical and electrical properties.

  9. Crystal growth in salt efflorescence

    Science.gov (United States)

    Zehnder, Konrad; Arnold, Andreas

    1989-09-01

    Salt efflorescences strongly affect wall paintings and other monuments. The external factors governing the crystal habits and aggregate forms are studied phenomenologically in laboratory experiments. As salt contaminated materials dry, slats crystallize forming distinct sequences of crystal habits and aggregate forms on and underneath the surfaces. Four phases may be distinguished: (1) Large individual crystals with equilibrium forms grow immersed in a thick solution film; (2) granular crusts of small isometric crystals grow covered by a thin solution film; (3) fibrous crusts of columnar crystals grow from a coherent but thin solution film so that the crystals are in contact with solution only at their base; (4) whiskers grow from isolated spots of very thin solution films into the air. The main factor governing these morphologies is the humidity of the substrate. A porous material cracks while granular crystals (approaching their equilibrium forms) grow within the large pores. As the fissures widen, the habits pass into columnar crystals and then into whiskers. Because this succession corresponds to the crystallization sequence on the substrate surface it can be traced back to the same growth conditions.

  10. Waveguides induced by grey screening solitons

    Institute of Scientific and Technical Information of China (English)

    Lu Ke-Qing; Zhao Wei; Yang Yan-Long; Zhang Mei-Zhi; Li Jin-Ping; Liu Hong-Jun; Zhang Yan-Peng

    2006-01-01

    We investigate the properties of waveguides induced by one-dimensional grey screening solitons in biased photore-fractive crystals. The results show that waveguides induced by grey screening solitons are always of single mode for all intensity ratios, i.e. the ratios between the peak intensity of the soliton and the dark irradiance. Our analysis indicates that the energy confined near the centre of the grey soliton and the propagation constant of the guided mode of the waveguide induced by the grey screening soliton increase monotonically with intensity ratio increasing. On the other hand, when the soliton greyness increases, the energy confined near the centre of the grey soliton and the propagation constant of the guided mode of the waveguide induced by the grey screening soliton decrease monotonically. Relevant examples are provided where photorefractive crystal is of the strontium barium niobate type.

  11. Exploration of the Applicable Conditions of x2 Test Combined with False Discovery Rate for Screening Pathogenic SNPs%探讨x2检验结合FDR筛选致病SNPs位点的适用条件

    Institute of Scientific and Technical Information of China (English)

    郑娟娟; 孙远洁; 李昂; 温琪; 佟海龙; 刘艳; 赵晓雯

    2012-01-01

    Objective To explore the applicable conditions of ^2 test combined with false discovery rate (FDR) for screening single nucleotide polymorphisms (SNPs) locus by investigating the different simulation conditions in the SNPs data. Methods According to the data of the first 5,000 SNPs in chromosome 22 of Utah residents with Northern and Western European ancestry from the CEPH collection released in HapMap III in February 2009, case ?control data were simulated by HAP-GEN2, and Tag SNPs were screened by Haploview4.2. The correct rates of different simulation conditions in screening pathogenic SNPs were compared. Results The methods of obtaining the relative risk (RR) were not significantly different. Three genetic models all showed that the correct rate increased with the rising RR. For the same RR, the additive model had the highest correct rate, the dominant model had the second, and the recessive model had the lowest. For the additive model with RR > 2.2, the dominant model with RR >4 and the recessive model with RR >5, the correct rate was over 60% . Conclusions Combination of x2 test with FDR has the best application in the additive model. In the actual scientific research, the feasibility of x2 test combined with FDR should be considered on the basis of the concrete conditions of the target disease.%目的 在单核苷酸多态性(SNPs)数据中探讨不同模拟条件x2检验结合错误发现率(FDR)筛选SNPs位点的适用条件.方法 依据2009年2月发布HapMapⅢ期美国犹他州北欧和西欧后裔人群22号染色体前5000个SNPs数据,采用HAPGEN2模拟病例对照数据,运用Haploview4.2筛选标签SNPs(TagSNPs),比较不同模拟条件筛选致病SNPs的正确率.结果 相对危险度(RR)获取方式无显著差异;3种遗传模型均表现正确率随RR值增大而增高,RR相同时,加性模型正确率最高,显性模型次之,隐性模型最低;加性模型RR>2.2、显性模型RR>4和隐性模型RR>5时,正确率超过60

  12. Photonic crystals as metamaterials

    Science.gov (United States)

    Foteinopoulou, S.

    2012-10-01

    The visionary work of Veselago had inspired intensive research efforts over the last decade, towards the realization of man-made structures with unprecedented electromagnetic (EM) properties. These structures, known as metamaterials, are typically periodic metallic-based resonant structures demonstrating effective constitutive parameters beyond the possibilities of natural material. For example they can exhibit optical magnetism or simultaneously negative effective permeability and permittivity which implies the existence of a negative refractive index. However, also periodic dielectric and polar material, known as photonic crystals, can exhibit EM capabilities beyond natural materials. This paper reviews the conditions and manifestations of metamaterial capabilities of photonic crystal systems.

  13. Crystallization and preliminary crystallographic data for a ternary complex between tissue factor, factor VIIa and a BPTI-derived inhibitor

    Science.gov (United States)

    Stura, Enrico A.; Ruf, Wolfram; Wilson, Ian A.

    1996-10-01

    The binding of tissue factor (TF) with the serine protease coagulation factor VIIa (VIIa) is the initial trigger for activation of the coagulation protease cascades. In complex with TF, VIIa has profoundly enhanced function in the limited proteolytic activation of the natural substrate factors X and IX. Here we report the screening and identification of crystallization conditions to produce diffraction quality crystals of the complex between TF · VIIa and a potent inhibitor (5L 15) derived from mutagenesis of the bovine pancreatic trypsin inhibitor (BPTI) sequence. The complex crystals were obtained from the soluble extracellular domain of tissue factor, expressed in Escherichia coli as a fusion protein, VIIa expressed in mammalian cells and recombinant 5L15. Because only 1.5 mg of complex were available for this work, a reverse screening based strategy was used in the search and optimization of the crystallization conditions. Two different crystal forms were obtained from polyethylene glycol 4000 and monomethyl polyethylene glycol 2000 with cacodylate buffer at pH 6.5 in the presence of sodium and calcium ions. The addition of magnesium and zinc have profound effects on the crystallization. Both crystal forms are trigonal with cell parameters a = b = 129.3 Å, c = 110.8 Å and a = b = 67.2 Å, c = 314.8 Å diffracting to 7 and 3.2 Å resolution, respectively, each with one molecule in the asymmetric unit. Complete data sets have been collected from each of these forms to the resolution to which the crystals diffract. A structural understanding of the interaction of VIIa with its cofactor TF to form a binary enzyme, and its inhibition by 5L15 will provide a basis for the development of antithrombotic strategies.

  14. Utility of the NECPAL CCOMS-ICO(©) tool and the Surprise Question as screening tools for early palliative care and to predict mortality in patients with advanced chronic conditions: A cohort study.

    Science.gov (United States)

    Gómez-Batiste, Xavier; Martínez-Muñoz, Marisa; Blay, Carles; Amblàs, Jordi; Vila, Laura; Costa, Xavier; Espaulella, Joan; Villanueva, Alicia; Oller, Ramon; Martori, Joan Carles; Constante, Carles

    2017-09-01

    The Surprise Question (SQ) identifies patients with palliative care needs. The NECPAL CCOMS-ICO(©) (NECPAL) tool combines the Surprise Question with additional clinical parameters for a more comprehensive assessment. The capacity of these screening tools to predict mortality is still unknown. To explore the predictive validity of the NECPAL and SQ to determine 12- to 24-month mortality. Longitudinal, prospective and observational cohort study. Three primary care centres, one general hospital, one intermediate care centre, and four nursing homes. Population cohort with advanced chronic conditions and limited life prognosis. Patients were classified according to SQ and NECPAL criteria and followed for 24 months. Data available to assess 1059 of 1064 recruited patients (99.6%) at 12 and 24 months: 837 patients were SQ+ and 780 were NECPAL+. Mortality rates at 24 months were as follows: 44.6% (SQ+) versus 15.8% (SQ-) and 45.8% (NECPAL+) versus 18.3% (NECPAL-) ( p = 0.000). SQ+ and NECPAL+ identification was significantly correlated with 24-month mortality risk (hazard ratios: 2.719 and 2.398, respectively). Both tools were highly sensitive (91.4, CI: 88.7-94.1 and 87.5, CI: 84.3-90.7) with high negative predictive values (84.2, CI: 79.4-89.0 and 81.7, CI: 77.2-86.2), with low specificity and positive predictive value. The prognostic accuracy of SQ and NECPAL was 52.9% and 55.2%, respectively. The predictive validity was slightly better for NECPAL. SQ and NECPAL are valuable screening instruments to identify patients with limited life prognosis who may require palliative care. More research is needed to increase its prognostic utility in combination with other parameters.

  15. Can Solution Supersaturation Affect Protein Crystal Quality?

    Science.gov (United States)

    Gorti, Sridhar

    2013-01-01

    The formation of large protein crystals of "high quality" is considered a characteristic manifestation of microgravity. The physical processes that predict the formation of large, high quality protein crystals in the microgravity environment of space are considered rooted in the existence of a "depletion zone" in the vicinity of crystal. Namely, it is considered reasonable that crystal quality suffers in earth-grown crystals as a result of the incorporation of large aggregates, micro-crystals and/or large molecular weight "impurities", processes which are aided by density driven convective flow or mixing at the crystal-liquid interface. Sedimentation and density driven convection produce unfavorable solution conditions in the vicinity of the crystal surface, which promotes rapid crystal growth to the detriment of crystal size and quality. In this effort, we shall further present the hypothesis that the solution supersaturatoin at the crystal surface determines the growth mechanism, or mode, by which protein crystals grow. It is further hypothesized that protein crystal quality is affected by the mechanism or mode of crystal growth. Hence the formation of a depletion zone in microgravity environment is beneficial due to inhibition of impurity incorporatoin as well as preventing a kinetic roughening transition. It should be noted that for many proteins the magnitude of neither protein crystal growth rates nor solution supersaturation are predictors of a kinetic roughening transition. That is, the kinetic roughening transition supersaturation must be dtermined for each individual protein.

  16. Impact of cooling condition on the crystal structure and surface quality of preferred c-axis-oriented AIN films for SAW devices

    Institute of Scientific and Technical Information of China (English)

    ZHANG Geng-yu; YANG Bao-he; ZHAO Jian; LI Cui-ping; LI Ming-ji

    2011-01-01

    AIN films with preferred c-axis orientation are deposited on Si substrates using the radio frequency (RF) magnetron sputtering method. The post-processing is carried out under the cooling conditions including high vacuum, low vacuum under deposition gas ambient and low vacuum under dynamic N2 ambient. Structures and morphologies of the films are analyzed by X-ray diffraction (XRD) and atomic force microscopy (AFM). The hardness and Young's modulus are investigated by the nanoindenter. The experimental results indicate that the (100) and (110) peak intensities decrease in the XRD spectra and the root-mean-square of roughness (Rrms) of the film decreases gradually with the increase of the cooling rate. The maximum values of the hardness and Young's modulus are obtained by cooling in low vacuum under deposition gas ambient. The reason for orientation variation of the films is explained from the perspective of the Al-N bond formation.

  17. Capillary and van der Waals interactions on CaF2 crystals from amplitude modulation AFM force reconstruction profiles under ambient conditions

    Directory of Open Access Journals (Sweden)

    Annalisa Calò

    2015-03-01

    Full Text Available There has been much interest in the past two decades to produce experimental force profiles characteristic of the interaction between nanoscale objects or a nanoscale object and a plane. Arguably, the advent of the atomic force microscope AFM was instrumental in driving such efforts because, in principle, force profiles could be recovered directly. Nevertheless, it has taken years before techniques have developed enough as to recover the attractive part of the force with relatively low noise and without missing information on critical ranges, particularly under ambient conditions where capillary interactions are believed to dominate. Thus a systematic study of the different profiles that may arise in such situations is still lacking. Here we employ the surfaces of CaF2, on which nanoscale water films form, to report on the range and force profiles that might originate by dynamic capillary interactions occurring between an AFM tip and nanoscale water patches. Three types of force profiles were observed under ambient conditions. One in which the force decay resembles the well-known inverse-square law typical of van der Waals interactions during the first 0.5–1 nm of decay, a second one in which the force decays almost linearly, in relatively good agreement with capillary force predicted by the constant chemical potential approximation, and a third one in which the attractive force is almost constant, i.e., forms a plateau, up to 3–4 nm above the surface when the formation of a capillary neck dominates the tip–sample interaction.

  18. The crystal acceleration effect for cold neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Braginetz, Yu. P., E-mail: aiver@pnpi.spb.ru [Petersburg Nuclear Physics Institute NRC KI (Russian Federation); Berdnikov, Ya. A. [Peter the Great St. Petersburg Polytechnic University (Russian Federation); Fedorov, V. V., E-mail: vfedorov@pnpi.spb.ru; Kuznetsov, I. A.; Lasitsa, M. V.; Semenikhin, S. Yu., E-mail: ssy@pnpi.spb.ru; Vezhlev, E. O.; Voronin, V. V., E-mail: vvv@pnpi.spb.ru [Petersburg Nuclear Physics Institute NRC KI (Russian Federation)

    2017-01-15

    A new mechanism of neutron acceleration is discussed and studied experimentally in detail for cold neutrons passing through the accelerated perfect crystal with the energies close to the Bragg one. The effect arises due to the following reason. The crystal refraction index (neutron-crystal interaction potential) for neutron in the vicinity of the Bragg resonance sharply depends on the parameter of deviation from the exact Bragg condition, i.e. on the crystal-neutron relative velocity. Therefore the neutrons enter into accelerated crystal with one neutron-crystal interaction potential and exit with the other. Neutron kinetic energy cannot vary inside the crystal due to its homogeneity. So after passage through such a crystal neutrons will be accelerated or decelerated because of the different energy change at the entrance and exit crystal boundaries.

  19. Crystal growth and structural analysis of zirconium sulphoselenide single crystals

    Indian Academy of Sciences (India)

    K R Patel; R D Vaidya; M S Dave; S G Patel

    2008-08-01

    A series of zirconium sulphoselenide (ZrSSe3–, where = 0, 0.5, 1, 1.5, 2, 2.5, 3) single crystals have been grown by chemical vapour transport technique using iodine as a transporting agent. The optimum condition for the growth of these crystals is given. The stoichiometry of the grown crystals were confirmed on the basis of energy dispersive analysis by X-ray (EDAX) and the structural characterization was accomplished by X-ray diffraction (XRD) studies. The crystals are found to possess monoclinic structure. The lattice parameters, volume, particle size and X-ray density have been carried out for these crystals. The effect of sulphur proportion on the lattice parameter, unit cell volume and X-ray density in the series of ZrSSe3– single crystals have been studied and found to decrease in all these parameters with rise in sulphur proportion. The grown crystals were examined under optical zoom microscope for their surface topography study. Hall effect measurements were carried out on grown crystals at room temperature. The negative value of Hall coefficient implies that these crystals are -type in nature. The conductivity is found to decrease with increase of sulphur content in the ZrSSe3– series. The electrical resistivity parallel to c-axis as well as perpendicular to -axis have been carried out in the temperature range 303–423 K. The results obtained are discussed in detail.

  20. Purification, crystallization and preliminary X-ray diffraction analysis of the carbohydrate-binding region of the Streptococcus gordonii adhesin GspB

    Energy Technology Data Exchange (ETDEWEB)

    Pyburn, Tasia M.; Yankovskaya, Victoria; Bensing, Barbara A.; Cecchini, Gary; Sullam, Paul M.; Iverson, T.M. (VA); (Vanderbilt); (UCSF)

    2012-07-11

    The carbohydrate-binding region of the bacterial adhesin GspB from Streptococcus gordonii strain M99 (GspB{sub BR}) was expressed in Escherichia coli and purified using affinity and size-exclusion chromatography. Separate sparse-matrix screening of GspB{sub BR} buffered in either 20 mM Tris pH 7.4 or 20 mM HEPES pH 7.5 resulted in different crystallographic behavior such that different precipitants, salts and additives supported crystallization of GspB{sub BR} in each buffer. While both sets of conditions supported crystal growth in space group P2{sub 1}2{sub 1}2{sub 1}, the crystals had distinct unit-cell parameters of a = 33.3, b = 86.7, c = 117.9 {angstrom} for crystal form 1 and a = 34.6, b = 98.3, c = 99.0 {angstrom} for crystal form 2. Additive screening improved the crystals grown in both conditions such that diffraction extended to beyond 2 {angstrom} resolution. A complete data set has been collected to 1.3 {angstrom} resolution with an overall R{sub merge} value of 0.04 and an R{sub merge} value of 0.33 in the highest resolution shell.

  1. 纤维素降解菌株的筛选及其产酶条件优化%Studies on Screening of Methane Fermentation Cellulose degrading Bacteria and its Optimization of Culture Conditions

    Institute of Scientific and Technical Information of China (English)

    高星爱; 黄枭; 张永锋; 赵新颖; 程孟秋; 刘鹏; 刘思言

    2012-01-01

    为了寻求快速有效降解沼气发酵有机质中的高分子化合物,本实验从腐殖质土壤中筛选到一株高效降解纤维素菌株,在以羧甲基纤维素钠为唯一碳源的液体培养基中培养,所产生的纤维素酶对玉米芯和滤纸均表现出较强降解能力.其次做了对菌株培养条件优化的实验,结果表明,菌株的最佳降解纤维素条件为反应温度30℃、发酵液接种量为1%、0.75%羧甲基纤维素钠为碳源、1.5%胰蛋白胨为氮源,优化菌株培养条件后,纤维素酶活力增加了2.8倍.%In order to be effective, rapid degradation of organic polymer compound biogas fermentation, from soil degradation to a plant screening high efficiency degradation cellulose strain. In sodium carboxyl methyl cellulose as the only carbon source of liquid medium training strains, the cellulose enzyme produced for several and filter paper are show have better degradation ability. Next to the optimization of the strains of the culture condition experiment results show that the best cellulolytic strains of the conditions for the reaction temperature 30°C, fermented liquid 1% inoculated quantity, carbon source sodium carboxyl methyl cellulose 0.75%, had 1.5% nitrogen pancreatic specially designed, and so on. Optimization strains after the culture condition, cellulose enzyme activity has increased 2.8times.

  2. Crystal Shape Evolution in Detached Bridgman Growth

    Science.gov (United States)

    Volz, M. P.; Mazuruk, K.

    2013-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. Existence of the gap provides several advantages, including no sticking of the crystal to the crucible wall, reduced thermal and mechanical stresses, reduced dislocations, and no heterogeneous nucleation by the crucible. Numerical calculations are used to determine the conditions in which a gap can exist. According to crystal shape stability theory, only some of these gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. Depending on the initial conditions and growth parameters, the crystal shape will evolve towards the crucible wall, towards a stable gap width, or towards the center of the crucible, collapsing the meniscus. The effect of a tapered crucible on dynamic stability is also described.

  3. 赤霉酸降解菌的筛选及其适宜降解条件的确定%Screening of Gibberellic Acid-degrading Strains and the Optimization of Its Degradation Conditions

    Institute of Scientific and Technical Information of China (English)

    李清平; 马丽莉; 唐洁; 黄灏; 姚开

    2012-01-01

    [ Objective] To screen a gibberellic acid-degrading strain and investigate the optimization of its degradation conditions. [ Method] An efficient gibberellic acid-degrading strain G-6 was screened from some domesticated strains tolerant to gibberellic acid ( GA3) by using basal salt medium with gibberellic acid as its only carbon source. In this paper, the effects of various factors on GA3 degradation by G-6 were investigated by single factor test and its condition for GA3 degradation was determined. [ Kesuit] The rate of GA3 degradation was up to 60.62% when the strain was incubated in 250 ml conical flask containing 40 ml mineral medium with 200 mg/L of gibberellic acid, 5. 0% of bacterial suspension and pH 7,0 on a rotary shaker (140 r/min) at 30 X for 120 h. [ Conclusion] The research supplied references for the biodegrada-tion pathway of GA3.%[目的]筛选一株赤霉酸( GA3)降解菌并探讨其适宜的降解备件.[方法]利用仅含赤霉酸为唯一碳源的基础盐培养基,对前期驯化得到的对GA3具有较强耐受性的微生物进行筛选,获得了具有较强降解GA3能力的菌株G-6;采用单因素试验系统考察了不同因素对菌株G-6降解GA3效果的影响,确定了其适宜的降解条件.[结果]在培养时间为120h、培养温度为30℃、初始pH为7.0、接种量(菌悬液OD600=1.000)为5.0% (V/V)、培养基中赤霉酸浓度为200 mg/L、摇床转速为140 r/min、250 ml锥形瓶培养基装量为40 ml的条件下,GA3降解率达到60.62%.[结论]为深入探讨GA3的生物降解途径提供了参考.

  4. Breast cancer screening

    Science.gov (United States)

    Mammogram - breast cancer screening; Breast exam - breast cancer screening; MRI - breast cancer screening ... performed to screen women to detect early breast cancer when it is more likely to be cured. ...

  5. DIFFERENT APPROACHES TO CRYSTALLIZATION OF MEMBRANE PROTEINS

    Directory of Open Access Journals (Sweden)

    Prakash G. Doiphode

    2012-01-01

    Full Text Available Crystallography is more like an art than science. Crystallizing membrane proteins are a big challenge; membrane proteins are present in the cell membrane and serve as cell support. The most important feature of membrane protein is that it contains both hydrophobic and hydrophilic regions on its surface. They are generally much more difficult to study than soluble proteins. The problem becomes more difficult when trying to obtain crystals to determine the high resolution structures of membrane proteins. We want to utilize this opportunity to briefly examine various approaches for crystallization of membrane proteins. The important factors for determining the success of crystallization experiments for membrane proteins lies in the purification, preparation of membrane samples, the environment in which the crystals are grown and the technique used to grow the crystals. All the X-ray structures of membrane protein are grown from preparations of detergents by different methods developed to crystallize. In this review different techniques for the crystallization of membrane proteins are being described. The cubic phase method also known as in meso method is discussed along with other methods to understand about the crystallization of membrane proteins, its general applicability, salt, detergent and screening effects on crystallization. Low volumes as nano-liter of samples can be used for crystallization. The effects of different detergents on the crystallization of membrane protein, as well as the use of surfactants like polyoxyethylene. Approach based on the detergent complexation to prove the ability of cyclodextrins to remove detergent from ternary mixtures in order to get 2D crystals. Crystallization of membrane proteins using non-ionic surfactants as well as Lipidic sponge phase and with swollen lipidic mesophases is discussed to better understand the crystallization of membrane proteins.

  6. Batch crystallization of rhodopsin for structural dynamics using an X-ray free-electron laser.

    Science.gov (United States)

    Wu, Wenting; Nogly, Przemyslaw; Rheinberger, Jan; Kick, Leonhard M; Gati, Cornelius; Nelson, Garrett; Deupi, Xavier; Standfuss, Jörg; Schertler, Gebhard; Panneels, Valérie

    2015-07-01

    Rhodopsin is a membrane protein from the G protein-coupled receptor family. Together with its ligand retinal, it forms the visual pigment responsible for night vision. In order to perform ultrafast dynamics studies, a time-resolved serial femtosecond crystallography method is required owing to the nonreversible activation of rhodopsin. In such an approach, microcrystals in suspension are delivered into the X-ray pulses of an X-ray free-electron laser (XFEL) after a precise photoactivation delay. Here, a millilitre batch production of high-density microcrystals was developed by four methodical conversion steps starting from known vapour-diffusion crystallization protocols: (i) screening the low-salt crystallization conditions preferred for serial crystallography by vapour diffusion, (ii) optimization of batch crystallization, (iii) testing the crystal size and quality using second-harmonic generation (SHG) imaging and X-ray powder diffraction and (iv) production of millilitres of rhodopsin crystal suspension in batches for serial crystallography tests; these crystals diffracted at an XFEL at the Linac Coherent Light Source using a liquid-jet setup.

  7. Screening of a Strain of Xylan-degrading Fungi and Optimization of Its Fermentation Conditions%一株降解木聚糖真菌的筛选及其发酵条件优化

    Institute of Scientific and Technical Information of China (English)

    张健; 汪桐; 徐争辉; 郭莹莹; 李峰

    2012-01-01

    [目的]从自然界中筛选出具有木聚糖酶活力的菌株,为今后降解农作物秸秆提供材料.[方法]以木聚糖为唯一碳源,从土壤中筛选能够降解木聚糖的菌株,并对其进行鉴定和发酵条件优化.[结果]从土壤中筛选出一株能够降解木聚糖的菌株,综合菌落、菌体形态特征和18S rRNA序列分析,初步鉴定该菌株为土曲霉(Asperergillus terreus thom.)GY-1.单因素试验研究表明,菌株GY-1最佳碳源为蔗糖,Mg2+能提高其木聚糖酶活力,最佳氮源为硝酸铵,最适温度为30℃,最适pH为6.0,该菌在培养52 h时木聚糖酶活力最高,为880.11 U/ml.L16(45)正交试验结果表明,GY-1的接种量以及培养基中蔗糖、Mg2+和硝酸铵的添加量对其木聚糖酶活力均有显著影响,GY-1菌株的最优发酵条件为:50 ml基础发酵培养基中,接种量2%,蔗糖1g,硝酸铵0.03 g,Mg2+0.004 mol.[结论]该研究首次报道了土曲霉具有木聚糖酶活力,为研究土曲霉降解木聚糖提供了一定的试验依据.%[Objective] To screen some xylan-degrading strains from nature and also provide material for degrading straw. [ Method ] The xylan was used as sole carbon source to screen some strain capable of degrading xylan cellulolytic from the soil, the strain was then identified, and its fermentation conditions were optimized. [ Result ] A xylan-degrading strain was screened out from the soil. According its colony, morphological characteristics and the 18S rRNA sequence analysis,the strain was identified to be Aspergillus terreus,GY-1. The single factor experiments showed that the best carbon source was sucrose, Mg2 + could improve xylanase activity,the best nitrogen source was ammonium nitrate,the most suitable temperature was 30℃ ,the most suitable pH was 6.0,xylanase activity of GY-1 was the highest for 880.11 U/ml in 52 h. And L16(4S) orthogonal test showed that the quantity of GY-1' s inoculation, sucrose, Mg2 + and ammonium nitrate dosage had a

  8. Condições microclimáticas em um parreiral irrigado coberto com tela plástica Microclimate conditions inside an irrigated vineyard covered with a plastic screen

    Directory of Open Access Journals (Sweden)

    Marco Antônio Fonseca Conceição

    2009-06-01

    microclimatic conditions inside the vineyard. The present work aimed to compare the meteorological conditions outside and inside a vineyard in the Jales region. The evaluations were carried out in the Tropical Viticulture Experimental Station of the Brazilian Agricultural Research Corporation (Embrapa, in Jales, SP. The grapevines were conducted in a pergola training system, covered with an 18% shadow plastic screen and irrigated using micro sprinklers. The meteorological data were registered outside and inside the vineyard using two automatic systems. It was observed that the plastic screen reduced the incident solar radiation (Sr above the canopy in 20%, in average. The Sr values bellow the canopy were lower than 20% of those registered outside, during the highest leaf expansion period. The air temperature and relative humidity did not differ from those registered outside the vineyard. During the irrigation the air temperature was reduced in 3% and the relative humidity was increased in 4%, in average.

  9. Photonic crystals

    CERN Document Server

    Busch, Kurt; Wehrspohn, Ralf B; Föll, Helmut

    2006-01-01

    The majority of the contributions in this topically edited book stems from the priority program SPP 1113 ""Photonische Kristalle"" run by the Deutsche Forschungsgemeinschaft (DFG), resulting in a survey of the current state of photonic crystal research in Germany. The first part of the book describes methods for the theoretical analysis of their optical properties as well as the results. The main part is dedicated to the fabrication, characterization and modeling of two- and three-dimensional photonic crystals, while the final section presents a wide spectrum of applications: gas sensors, micr

  10. 剑麻总皂苷高产菌的筛选及发酵条件的优化%Screening High-Yielding Strain for Extracting Agave sisalana perr.ex Engelm Total Saponins and Its Fermentation Condition

    Institute of Scientific and Technical Information of China (English)

    周菲菲; 郝再彬; 易克贤; 郑金龙; 王秀丽

    2014-01-01

    以绿色环保发酵生产提取剑麻(Agave sisalana perr.ex Engelm)总皂苷为目标,采集土壤样品,对菌株进行初筛和复筛得到1株菌株,编号JMZ-N06。通过料液比、发酵温度、发酵时间、发酵液初始pH四因素三水平的正交试验,确定了该菌的最适发酵条件为料液比1:20(g:mL),发酵时间60 h,发酵温度32℃,发酵液初始pH 6.0。%To environmentally ectract total saponins from Agave sisalana perr.ex Engelm , one strain of No. JMZ-N06 was obtained after twice screen from hundreds of soil samples. The optimal fermentation conditions were determined by orthogonal test of three levels and four factors including ratio of material to liquid, fermentation temperature, fermentation time, initial pH in fermentation broth. The results showed that the yield of total saponins from Agave sisalana perr.ex Engelm was 142.5 mg∕g when fermented 60 h under 32℃ with the material to liquid ratio of 1:20(g:mL) and initial pH of 6.0.

  11. Vision Screening by Color Photography

    Science.gov (United States)

    Jayroe, R.; Richardson, J. R.; Kerr, J.; Hay, S.; Mcbride, R.

    1985-01-01

    Screening test developed for detecting a range of vision defects in eye, including common precursors to amblyopia. Test noninvasive, safe, and administered easily in field by operator with no medical training. Only minimal momentary cooperation of subject required: Thus, test shows promise for use with very young children. Test produces color-slide images of retinas of eyes under specially-controlled lighting conditions. Trained observer screens five children per minute.

  12. Screening of a Microbial Strain for Banana Fiber Retting and Its Cultivation Condition for the Enzyme Production%香蕉纤维脱胶茵的筛选及其产酶条件的初步研究

    Institute of Scientific and Technical Information of China (English)

    黄小龙; 陶祥艳; 曹树威; 黄东益

    2011-01-01

    Banana fiber is a new raw material for textile industry. Shortage of retting ways and process limits the exploitation and application of banana fiber. This paper deals with the retting of banana fibers with microbial methods. Screened with a method of transparent zones, an actinomyces strain 51181 decomposing banana hemicellulose was isolated from the rhizosphere soil. The strain could degrade about 38% of the gum of banana fiber by retting experiment in the lab, The optimal conditions for hemicellulase production by the strain 51181 were determined. The activity of hemicellulase reached to 48.63 U/mL under the optimum conditions. It showed that the strain 51181 had good applying prospects in microbial retting and enzymatic retting of banana fiber.%香蕉纤维是纺织行业的一种新型纤维原料,其脱胶方法和工艺研究的缺乏制约着相关的开发与利用.本文就香蕉纤维的微生物脱胶进行了初步研究,采用透明圈法从土壤中筛选到一株具有降解香蕉半纤维素能力的放线菌菌株51181,利用它脱胶可去除香蕉纤维38%的胶质;对菌株51181产半纤维素酶的条件优化后,该菌株所产的半纤维素酶活达48.63 U/mL,表明该菌株在香蕉纤维微生物脱胶及酶法脱胶方面具有一定的应用前景.

  13. Enzymatic Preparation of Small Molecule Soybean Peptide Protease Screening and Conditions Optimization of Enzymatic Hydrolysis%酶法制备小分子大豆肽的蛋白酶筛选以及酶解条件优化

    Institute of Scientific and Technical Information of China (English)

    周川农; 刘飞; 刘丹怡; 张欢; 于殿宇; 程宝晶

    2014-01-01

    本研究对制备小分子大豆肽的蛋白酶进行筛选,并对酶解条件进行优化。综合考虑酶量对产物的水解度、平均分子量及游离氨基酸的影响,确定酶解的最佳条件为:温度55℃, pH值8.5,底物浓度为10%,分别加入1.5%的木瓜蛋白酶、菠萝蛋白酶、无花果蛋白酶和3942中性蛋白酶,调pH值至4.5,再分别加入2.5%的Fromase真菌蛋白酶和537酸性蛋白酶。结果显示,多酶复合水解可提高蛋白质降解率,并尽可能降低多肽的相对分子质量。%In this study, proteinases were screened to prepare for small molecule soybean peptide, and conditions of enzyme hydrolysis were optimized. Influence of enzyme amount on products′ degree of hydrolysis ( DH) , average molecular weight and free amino acid was token into account. Results showed that optimum conditions were:temperature 55℃, pH 8.5, substrate concentration 10%, and then the liquid mixed with amount of 1.5%of papain, bromelain, ficin and 3942 neutral protease. Next, to adjust the pH to 4.5, then liguid mixed with amount of 2.5% of Fromase Fungus protease and 537 acid protease. As a result, composite enzyme hydrolyzed protein degradation rate could be improved and as far as possible to reduce the molecular mass of peptides.

  14. Photonic crystals in epitaxial semiconductors

    CERN Document Server

    La Rue, R M de

    1998-01-01

    The title of the paper uses the expression "photonic crystals". By photonic crystals, we mean regular periodic structures with a substantial refractive index variation in one-, two- or three- dimensional space. Such crystals can $9 exist naturally, for example natural opal, but are more typically fabricated by people. Under sufficiently strong conditions, i.e., sufficiently large refractive index modulation, correct size of structural components, and $9 appropriate rotational and translational symmetry, these crystals exhibit the characteristics of a photonic bandgap (PBG) structure. In a full photonic bandgap structure there is a spectral stop band for electromagnetic waves $9 propagating in any direction through the structure and with an arbitrary state of polarization. This behavior is of interest both from a fundamental viewpoint and from the point of view of novel applications in photonic devices. The $9 paper gives an outline review of work on photonic crystals carried out by the Optoelectronics Researc...

  15. Growth habit of polar crystals

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Using coordination polyhedron rule, growth habit of polar crystals such as ZnO, ZnS and SiO2 is investigated. It shows that the growth rates in the positive and negative polar axis directions are different. The theoretical growth habit of ZnO crystal is hexagonal prism and the growth rates of its various faces are:V{0001}>V{0111}-->V{0110}->V{0111}->V{0001}-. The growth habit of ZnS crystal is tetrahedron and its growth rates of different crystal faces are: V{111}>V{001}>V{001} =V{100} =. The growth rate relationship between positive and negative polar axis directions of SiO2 crystal V[1120]-->V[1120]-.is These results are in agreement with the growth habits observed under hydrothermal conditions. The different growth rates between positive and negative polar axis directions cannot be explained by PBC theory.

  16. OPTIMASI KONDISI PEMURNIAN ASAM LEMAK OMEGA-3 DARI MINYAK HASIL SAMPING PENEPUNGAN TUNA (Thunnus sp DENGAN KRISTALISASI UREA [Optimizing Conditions for the Purification of Omega-3 Fatty Acids from By-product of Tuna (Thunnus sp Meal Processing by Urea Crystallization

    Directory of Open Access Journals (Sweden)

    Teti Estiasih1*

    2009-12-01

    Full Text Available Omega-3 fatty acids (-3 are proven to have health beneficial effects. Some effort had been done to obtained oil high in -3 fatty acids. Among the methods developed, urea crystallization was preferred because it is simple, economic, and result in high purity of fatty acids. A source that had not been widely explored for -3 fatty acids production is the by-product of tuna meal processing. This research studied the optimization condition for separation and purification of -3 fatty acids from the by-product of tuna meal processing by urea crystallization. Crystallization reaction conditions of urea inclusion were optimized using the response surface methodology, and the model was developed.Optimization result showed a quadratic polynomial regression equation of Y= 140,52677X1 + 8,38203X2 – 19,85850X12 – 0,12173X22 – 0,74000X1X2 – 240,33546 with X1=urea to fatty acid ratio and X2=crystallization time. Maximum response was obtained at urea to fatty acid ratio of 3,07:1,crystallization time of 25,10 hours, and predicted response was 80,60%. Analysis of variance showed that urea to fatty acid ratio and crystallization time affected response. Under optimal conditions, the product was 3.89 times concentrated and the purity of -3 fatty acids was 81,98%. Verification result revealed that the predicted value from this model was reasonably close to the experimentally observed value. Urea crystallization process changed quality parameters that were oxidation level (peroxide value, anisidin value, and totox value, Fe and Cu content, P content, and water content. The changes were caused by adsorption of primary and secondary oxidation products, part of metals, and phosphoric compound onto unsaponifiable matters or soluble into water.

  17. Ribbon Crystals

    DEFF Research Database (Denmark)

    Bohr, Jakob; Markvorsen, Steen

    2013-01-01

    A repetitive crystal-like pattern is spontaneously formed upon the twisting of straight ribbons. The pattern is akin to a tessellation with isosceles triangles, and it can easily be demonstrated with ribbons cut from an overhead transparency. We give a general description of developable ribbons...

  18. Therapeutic Crystals

    Science.gov (United States)

    Bond, Charles S.

    2014-01-01

    Some readers might not fully know what the difference is between crystallography, and the "new age" practice of dangling crystals around the body to capitalise on their healing energy. The latter is often considered to be superstition, while ironically, the former has actually resulted in real rationally-based healing of human diseases…

  19. Screening and fermentation conditions of β-glucanase producing strain from basidiomycetes by multiple mutagensis%β-葡聚糖酶担子菌种复合诱变选育及发酵条件研究

    Institute of Scientific and Technical Information of China (English)

    李蕤; 张洁; 蔡敬民; 吴克; 阚劲松

    2011-01-01

    用平板透明圈法对高温平菇(Pleurotus ostreatus)、金针菇(Flammulina velutipes)、香菇(Lentinus edodes)等担子菌菌种进行筛选.选取高温平菇作为诱变出发菌株进行复合诱变处理并进行初筛.选取透明圈半径与菌落半径比值较大的菌株接种至发酵培养基进行复筛.最终筛选出一株产β-葡聚糖酶能力较强的高温平菇突变菌株P32,并进行产酶条件的优化.结果表明:最佳碳源比为麸皮∶β-葡聚糖∶麦秸粉=9∶1∶1,氮源为4 g/L (NH4)2CO3,起始pH值5.0,培养温度32℃.该菌株在优化条件下产β-葡聚糖酶的能力最强,酶活力达到60.08 IU/mL.%Pleurotus ostreatus, Flam mulina velutipes and Lentinus edodes and so on , were screened by transparent zonesm ethod . Pleurotus ostreatus as initial strain was treated by multiple mutagensis and then the mutants with the bigger ratio of transparent zones radius to colony radius were chosen for further screening . At last, the Pleurotus ostreatus P32 producing high β-glucanase activity was obtained . The results showed that the optinum carbon sources were bran , β-gjucan and barley straw powder in the ratio of 9:1:1 ; the optinum nitrogen source was 4g/L (N H4 )2 CO3; the optinum initial pH and temperature were pH 5 .0 and 32℃ , respectively . Under the optimized conditions, the β-glucanase ability of Pleurotus ostreatus P32 reached as high as 60 .08 IU /m L .

  20. Screening and optimization of fermentation conditions of Schizochytrium strain with high-productive DHA%一株高产DHA菌株的筛选及其发酵条件优化

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    采用松花粉垂钓法分离得到一株DHA高产菌Schizochytrium sp.ZR-01,通过研究培养基和培养条件对菌株发酵生产DHA的影响,确定了菌株的最适发酵条件为:葡萄糖50 g/L,大豆蛋白胨10 g/L,酵母粉4 g/L,海水晶15 g/L,发酵温度28℃,初始pH 6.0,500 mL三角瓶装液量150 mL.在最适发酵条件下培养3 d,菌体干重和DHA含量分别达到23.5 g/L和6.9 g/L.此外考察了10 L发酵罐补料分批发酵过程,通过流加50%的葡萄糖和后期的低温胁迫,最终菌体干重和DHA含量分别高达72.1 g/L和21.7 g/L.%The Schizochytrium sp. ZR -01 strain with high -productive DHA was separated using pine pollen as bait. The effects of medium and cultural conditions on fermentation and production of DHA of the strain were studied, and the optimal cultural conditions of the strain were obtained as follows:glucose 50 g/L, soybean peptone 10 g/L, yeast extract 4 g/L, seawater crystal 15 g/L, fermentation temperature 28℃, initial pH 6. 0, liquid volume 150 mL in 500 mL triangular flask. After culturing for 3 d under these conditions, the dry weight and DHA content of the strain reached 23. 5 g/L and 6. 9 g/L, respec-tively. In addition, the fed-batch fermentation in 10 L fermenter was studied. The dry weight and DHA content of the strain reached 72 . 1 g/L and 21 . 7 g/L respectively by feeding 50% glucose and low temperature stress in the late stage.

  1. Debye screening

    Science.gov (United States)

    Brydges, David C.; Federbush, Paul

    1980-10-01

    The existence and exponential clustering of correlation functions for a classical coulomb system at low density or high temperature are proven using methods from constructive quantum field theory, the sine gordon transformation and the Glimm, Jaffe, Spencer expansion about mean field theory. This is a vindication of a belief of long standing among physicists, known as Debye screening. That is, because of special properties of the coulomb potential, the configurations of significant probability are those in which the long range parts of r -1 are mostly cancelled, leaving an effective exponentially decaying potential acting between charge clouds. This paper generalizes a previous paper of one of the authors in which these results were obtained for a special lattice system. The present treatment covers the continuous mechanics situation, with essentially arbitrary short range forces and charge species. Charge symmetry is not assumed.

  2. Photonic crystals principles and applications

    CERN Document Server

    Gong, Qihuang

    2013-01-01

    IntroductionPrimary Properties of Photonic CrystalsFabrication of Photonic CrystalsPhotonic Crystal All-Optical SwitchingTunable Photonic Crystal FilterPhotonic Crystal LaserPhotonic Crystal Logic DevicesPhotonic Crystal Sensors

  3. Size effects in crystal plasticity

    DEFF Research Database (Denmark)

    Borg, Ulrik

    2007-01-01

    Numerical analyses of plasticity size effects have been carried out for different problems using a developed strain gradient crystal plasticiy theory. The theory employs higher order stresses as work conjugates to slip gradients and uses higher order boundary conditions. Problems on localization...... of plastic flow in a single crystal, grain boundary effects in a bicrystal, and grain size effects in a polycrystal are studied. Single crystals containing micro-scale voids have also been analyzed at different loading conditions with focus on the stress and deformation fields around the voids, on void...... growth and interaction between neighboring voids, and on a comparison between the developed strain gradient crystal plasticity theory and a discrete dislocation plasticity theory. Furthermore, voids and rigid inclusions in isotropic materials have been studied using a strain gradient plasticity theory...

  4. Photoelastic sphenoscopic analysis of crystals

    Energy Technology Data Exchange (ETDEWEB)

    Montalto, L. [DIISM, Dip. Di Ingegneria Industriale e Scienze Matematiche—Università Politecnica delle Marche, Ancona (Italy); SIMAU, Dip. Di Scienze e Ingegneria della Materia, dell’ambiente ed Urbanistica—Università Politecnica delle Marche, Ancona (Italy); Rinaldi, D. [SIMAU, Dip. Di Scienze e Ingegneria della Materia, dell’ambiente ed Urbanistica—Università Politecnica delle Marche, Ancona (Italy); Scalise, L.; Paone, N. [DIISM, Dip. Di Ingegneria Industriale e Scienze Matematiche—Università Politecnica delle Marche, Ancona (Italy); Davì, F. [DICEA, Dip. Di Ingegneria Civile, Edile e Architettura—Università Politecnica delle Marche, Ancona (Italy)

    2016-01-15

    Birefringent crystals are at the basis of various devices used in many fields, from high energy physics to biomedical imaging for cancer detection. Since crystals are the main elements of those devices, a great attention is paid on their quality and properties. Here, we present a methodology for the photoelastic analysis of birefringent crystals, based on a modified polariscope. Polariscopes using conoscopic observation are used to evaluate crystals residual stresses in a precise but time consuming way; in our methodology, the light beam shape, which impinges on the crystal surface, has been changed from a solid cone (conoscopy) to a wedge (sphenoscopy). Since the polarized and coherent light is focused on a line rather than on a spot, this allows a faster analysis which leads to the observation, at a glance, of a spatial distribution of stress along a line. Three samples of lead tungstate crystals have been observed using this technique, and the obtained results are compared with the conoscopic observation. The samples have been tested both in unloaded condition and in a loaded configuration induced by means of a four points bending device, which allows to induce a known stress distribution in the crystal. The obtained results confirm, in a reliable manner, the sensitivity of the methodology to the crystal structure and stress.

  5. Thermally induced atmospheric pressure gas discharges using pyroelectric crystals

    Science.gov (United States)

    Johnson, Michael J.; Linczer, John; Go, David B.

    2014-12-01

    Using a heated pyroelectric crystal, an atmospheric pressure gas discharge was generated through the input of heat. When put through a change in temperature, the polarization of a pyroelectric can change significantly, creating a substantial electric potential at its surface. When configured with a grounded sharp counter electrode, a large inhomogeneous electric field forms in the interstitial gas to initiate a corona-like discharge. Under constant heating conditions, gaseous ions drifting to the pyroelectric accumulate and screen the electric field, extinguishing the discharge. By thermally cycling the pyroelectric, negative and positive discharges are generated during heating and cooling, respectively, with peak currents on the order of 80 nA. Time-integrated visualization confirmed the generation of both a corona-like discharge and a surface discharge on the pyroelectric. Parametric studies identified that thermal cycling conditions significantly influence discharge formation for this new atmospheric pressure discharge approach.

  6. Seeding for sirtuins: microseed matrix seeding to obtain crystals of human Sirt3 and Sirt2 suitable for soaking

    Energy Technology Data Exchange (ETDEWEB)

    Rumpf, Tobias [Albert-Ludwigs-University Freiburg, Albertstrasse 25, 79104 Freiburg, Baden-Württemberg (Germany); Gerhardt, Stefan; Einsle, Oliver, E-mail: einsle@biochemie.uni-freiburg.de [Albert-Ludwigs-University Freiburg, Albertstrasse 21, 79104 Freiburg, Baden-Württemberg (Germany); Jung, Manfred, E-mail: einsle@biochemie.uni-freiburg.de [Albert-Ludwigs-University Freiburg, Albertstrasse 25, 79104 Freiburg, Baden-Württemberg (Germany)

    2015-11-18

    In the present study, microseed matrix seeding was successfully applied to obtain a large number of crystals of the human sirtuin isotypes Sirt2 and Sirt3. These crystals appeared predictably in diverse crystallization conditions, diffracted to a higher resolution than reported in the literature and were subsequently used to study the protein–ligand interactions of two indole inhibitors. Sirtuins constitute a family of NAD{sup +}-dependent enzymes that catalyse the cleavage of various acyl groups from the ∊-amino group of lysines. They regulate a series of cellular processes and their misregulation has been implicated in various diseases, making sirtuins attractive drug targets. To date, only a few sirtuin modulators have been reported that are suitable for cellular research and their development has been hampered by a lack of structural information. In this work, microseed matrix seeding (MMS) was used to obtain crystals of human Sirt3 in its apo form and of human Sirt2 in complex with ADP ribose (ADPR). Crystal formation using MMS was predictable, less error-prone and yielded a higher number of crystals per drop than using conventional crystallization screening methods. The crystals were used to solve the crystal structures of apo Sirt3 and of Sirt2 in complex with ADPR at an improved resolution, as well as the crystal structures of Sirt2 in complex with ADPR and the indoles EX527 and CHIC35. These Sirt2–ADPR–indole complexes unexpectedly contain two indole molecules and provide novel insights into selective Sirt2 inhibition. The MMS approach for Sirt2 and Sirt3 may be used as the basis for structure-based optimization of Sirt2/3 inhibitors in the future.

  7. Screening, identification and optimization of fermentation conditions of an antagonistic actinomycetes strain to Setosphaeria turcica%玉米大斑病生防放线菌的筛选鉴定及发酵条件优化

    Institute of Scientific and Technical Information of China (English)

    赵淑莉; 任飞娥; 刘金亮; 秦建春; 潘洪玉

    2012-01-01

    [Objective ] To isolate and screen antagonistic actinomyces strains with inhibitory activity on Setosphaeria turcica from soil. [ Method] Actinomycetes were isolated by Pour Plate method. Antagonistic actinomycetes were screened by confrontation culture, cylinder plate, suppression of mycelial growth and spore germination method in vitro. Strain BZ45 were identified by morphological, cultural, physiological and biochemical characteristics and 16S rDNA sequence analysis. The fermentation condition was optimized by single factor and orthogonal experiment. [Result] Strain BZ45 showed antagonistic to 8 plant pathogens. Its filtrate inhibited the mycelial growth and spore germination of Setosphaeria turcica CC9. Strain BZ45 belonged to Streptomyces spectabilis. The optimum culture conditions of strain BZ45 were with a medium of 1. 5% fructose, 3.0% peptone, 0.1% KH2PO4, 0.04% NaCl, 0.1% CaCO3 at initial pH of 7. 2, liquid volume 50 mL in 250 mL flask, 200 rpm at 28^ , inoculation size of 10% for 4 d. [Conclusion] Strain BZ45 was identified as Streptomyces spectabilis and antagonistic against Setosphaeria turcica CC9.%[目的]从土壤中筛选对玉米大斑病菌具有较强拮抗作用的放线菌菌株.[方法]采用稀释涂布法分离;采用平板对峙法、牛津杯法、抑制菌丝生长速率法、抑制孢子萌发法进行拮抗菌的筛选;根据菌株BZ45的形态与培养特征、生理生化特性、16SrDNA序列分析对其进行鉴定.通过单因素试验和正交设计试验优化培养基组分及发酵条件.[结果]通过分离筛选得到一株具有强抑制作用的放线菌菌株BZ45,它对常见的8种病原真菌均有拮抗作用,菌株BZ45的发酵滤液对玉米大斑病菌(Setosphaeria turcica)CC9的菌丝生长和孢子萌发均有较强的抑制作用.菌株BZ45与链霉菌中的壮观链霉菌(Streptomyces spectabilis)的亲缘关系较近,且形态与培养特征、生理生化特性与壮观链霉菌的基本相符.研究表

  8. The Mineralogy, Geochemistry, and Redox State of Multivalent Cations During the Crystallization of Primitive Shergottitic Liquids at Various (f)O2. Insights into the (f)O2 Fugacity of the Martian Mantle and Crustal Influences on Redox Conditions of Martian Magmas.

    Science.gov (United States)

    Shearer, C. K.; Bell, A. S.; Burger, P. V.; Papike, J. J.; Jones, J.; Le, L.; Muttik, N.

    2016-01-01

    The (f)O2 [oxygen fugacity] of crystallization for martian basalts has been estimated in various studies to range from IW-1 to QFM+4 [1-3]. A striking geochemical feature of the shergottites is the large range in initial Sr isotopic ratios and initial epsilon(sup Nd) values. Studies by observed that within the shergottite group the (f)O2 [oxygen fugacity] of crystallization is highly correlated with these chemical and isotopic characteristics with depleted shergottites generally crystallizing at reduced conditions and enriched shergottites crystallizing under more oxidizing conditions. More recent work has shown that (f)O2 [oxygen fugacity] changed during the crystallization of these magmas from one order of magnitude in Y980459 (Y98) to several orders of magnitude in Larkman Nunatak 06319. These real or apparent variations within single shergottitic magmas have been attributed to mixing of a xenocrystic olivine component, volatile loss-water disassociation, auto-oxidation during crystallization of mafic phases, and assimilation of an oxidizing crustal component (e.g. sulfate). In contrast to the shergottites, augite basalts such as NWA 8159 are highly depleted yet appear to be highly oxidized (e.g. QFM+4). As a first step in attempting to unravel petrologic complexities that influence (f)O2 [oxygen fugacity] in martian magmas, this study explores the effect of (f)O2 [oxygen fugacity] on the liquid line of descent (LLD) for a primitive shergottite liquid composition (Y98). The results of this study will provide a fundamental basis for reconstructing the record of (f)O2 [oxygen fugacity] in shergottites and other martian basalts, its effect on both mineral chemistries and valence state partitioning, and a means for examining the role of crystallization (and other more complex processes) on the petrologic linkages between olivine-phyric and pyroxene-plagioclase shergottites.

  9. Screening of alginate degrading bacteria and optimization of fermentation conditions%一株高效褐藻胶降解菌的筛选及其发酵条件的优化

    Institute of Scientific and Technical Information of China (English)

    王霁宁; 严孝强; 杜宗军

    2012-01-01

    针对8株已知有褐藻胶降解酶活性的菌株,以褐藻酸钠为唯一碳源,驯化培养后筛选得到一株高效降解菌中华黄海杆菌QM42.经过发酵培养实验,确定其最佳产酶条件(w/v):以蛋白胨为氮源,以褐藻酸钠为碳源,褐藻酸钠浓度0.4%~0.7%,培养盐度5%~7%,培养初始pH值为7,培养温度31℃,150r/min摇床发酵72h,粗酶液酶活力达到9.74U/mL.%A screening work was carried out to get marine bacterium with high alginate lyase activity by using alginate as sole source of carbon. Strain QM42 was selected for further studies among the 8 alginate-degrading bacteria strains. Results showed that the optimal carbon and nitrogen sources for marine bacterium QM42 to produce extracellular alginate lyase were alginate and peptone, respectively. The optimal concentration of carbon source was 0.4%~0.7%(w/v). The culture temperature was 311. The initial pH value of the liquid. medium was about 7, and the salinity was 5%~7%. The optimal harvest time for extracellular alginate lyase was about 72h with 150r/min rotation. Under such conditions the marine bacterium QM42 could produce 9.74U/ml alginate lyase in crude fermentation medium.

  10. Predicting crystal structures of organic compounds.

    Science.gov (United States)

    Price, Sarah L

    2014-04-07

    Currently, organic crystal structure prediction (CSP) methods are based on searching for the most thermodynamically stable crystal structure, making various approximations in evaluating the crystal energy. The most stable (global minimum) structure provides a prediction of an experimental crystal structure. However, depending on the specific molecule, there may be other structures which are very close in energy. In this case, the other structures on the crystal energy landscape may be polymorphs, components of static or dynamic disorder in observed structures, or there may be no route to nucleating and growing these structures. A major reason for performing CSP studies is as a complement to solid form screening to see which alternative packings to the known polymorphs are thermodynamically feasible.

  11. A new view on crystal harvesting

    Science.gov (United States)

    Luft, Joseph R.; Grant, Thomas D.; Wolfley, Jennifer R.; Snell, Edward H.

    2014-01-01

    X-ray crystallography typically requires the mounting of crystals, which can make the sample difficult to manipulate when it is small and the microscope objective is close to the crystallization plate. By simply moving the objective to the bottom of a clear crystallization plate (inverting the normal view), crystals were able to be manipulated and harvested from wells having a 0.9 mm diameter and 5.0 mm depth. The mounting system enabled the structural solution of the 187 amino acid N-terminal domain of Saccharomyces cerevisiae glutaminyl-tRNA synthetase from crystals that appeared during high-throughput screening but proved recalcitrant to scale-up and optimization. While not a general mounting solution, the simple expedient of removing the objective lens from the area where manipulation and harvesting occur greatly facilitates the manual, or even automated, process. PMID:24904250

  12. Screening Effect in Charge Qubit

    Institute of Scientific and Technical Information of China (English)

    HUA Ming; XIAO Xiao; GAO Yi-Bo

    2011-01-01

    We study the influence of screening effect on quantum decoherence for charge qubit and the process of quantum information storage. When the flux produced by the circulating current in SQUID loop is considered, screening effect is formally characterized by a LC resonator. Using large-detuning condition and Fr(o)hlich transformation in the qubit-cavity-resonator system, we calculate the decoherence factor for charge qubit and the effective qubit-cavity Hamiltonian. The decoherence factor owns a factorized structure, it shows that screening effect is a resource of decoherence for charge qubit. The effective Hamiltonian shows that the screening effect results in a frequency shift for charge qubit and a modified qubit-cavity coupling constant induced by a LC resonator.

  13. Screening the flocculent bacteria and optimizing the fermentation conditions in treating slaughter-releasing sewage%絮凝菌的筛选、培养条件优化及对屠宰场废水的处理

    Institute of Scientific and Technical Information of China (English)

    宋永庆; 张龙; 李南华; 柴化建; 赵海泉

    2016-01-01

    采用分离纯化技术从淤泥样品中筛选出一株高效絮凝剂产生菌,编号为M-3.通过形态学观察、生理生化鉴定及16S rDNA序列同源性比对,鉴定M-3菌为蜡样芽胞杆菌.对M-3菌株进行产絮培养条件优化,并测定了最佳培养条件下制备的活性絮凝物质对屠宰场废水的絮凝效率.结果表明:该菌最佳培养条件为pH =7.0,培养温度30℃,装液量200 mL/500 mL;活性絮凝物对高岭土悬浮液的絮凝率达88.4%;在屠宰场废水pH值超过8时有较好的絮凝效果,pH值为12时效果最佳,絮凝率和COD去除率分别为78.0%、34.6%,絮凝剂最佳投加比例为1~2 mL/100 inL,助絮剂1% CaCl2最佳投加比例为3~4 mL/100 mL.%This paper is intended to present its study on the flocculation effect for the sewage treatment in the slaughter house.For the research purpose,we have cultured and screened the active microbial flocculates through separating and purifying the effective flocculants from the sih samples.So far we have screened out three lines of effective flocculants to produce the bacteria we need,and then identified them as M-3,which can be achieved through the flocculation rate of 80% and formed larger alumen ustum as a kind of bacillus cereus through the morphological observation,physiological and biochemical identification and 16S rDNA sequence homology comparison.In addition,we have also managed to improve the condition of flocculate cultivation for M 3 bacterial strain,and obtained the optimal condition of cultivation,including the initial pH,the culture temperature and the fluid volume desirable.When we tested the flocculating efficiency of active flocculating substance prepared under the optimum condition for the sewage treatment in the slaughter-house,we have studied its effect on the flocculaton efficiency by adjusting pH value of the sewage and obtained the suitable ratio of flocculent to flocculent aids on this basis.Thus,it can be concluded that the

  14. Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth

    Science.gov (United States)

    Foster, Jonathan A.; Piepenbrock, Marc-Oliver M.; Lloyd, Gareth O.; Clarke, Nigel; Howard, Judith A. K.; Steed, Jonathan W.

    2010-12-01

    We describe the use of low-molecular-weight supramolecular gels as media for the growth of molecular crystals. Growth of a range of crystals of organic compounds, including pharmaceuticals, was achieved in bis(urea) gels. Low-molecular-weight supramolecular gelators allow access to an unlimited range of solvent systems, in contrast to conventional aqueous gels such as gelatin and agarose. A detailed study of carbamazepine crystal growth in four different bis(urea) gelators, including a metallogelator, is reported. The crystallization of a range of other drug substances, namely sparfloxacin, piroxicam, theophylline, caffeine, ibuprofen, acetaminophen (paracetamol), sulindac and indomethacin, was also achieved in supramolecular gel media without co-crystal formation. In many cases, crystals can be conveniently recovered from the gels by using supramolecular anion-triggered gel dissolution; however, crystals of substances that themselves bind to anions are dissolved by them. Overall, supramolecular gel-phase crystallization offers an extremely versatile new tool in pharmaceutical polymorph screening.

  15. Effects of impurities on crystal growth in fructose crystallization

    Science.gov (United States)

    Chu, Y. D.; Shiau, L. D.; Berglund, K. A.

    1989-10-01

    The influence of impurities on the crystallization of anhydrous fructose from aqueous solution was studied. The growth kinetics of fructose crystals in the fructose-water-glucose and fructose-water-difructose dianhydrides systems were investigated using photomicroscopic contact nucleation techniques. Glucose is the major impurity likely to be present in fructose syrup formed during corn wet milling, while several difructose dianhydrides are formed in situ under crystallization conditions and have been proposed as a cause in the decrease of overall yields. Both sets of impurities were found to cause inhibition of crystal growth, but the mechanisms responsible in each case are different. It was found that the presence of glucose increases the solubility of fructose in water and thus lowers the supersaturation of the solution. This is probably the main effect responsible for the decrease of crystal growth. Since the molecular structures of difructose dianhydrides are similar to that of fructose, they are probably "tailor-made" impurities. The decrease of crystal growth is probably caused by the incorporation of these impurities into or adsorption to the crystal surface which would accept fructose molecules in the orientation that existed in the difructose dianhydride.

  16. Mental Health Screening Center

    Science.gov (United States)

    ... Releases & Announcements Public Service Announcements Partnering with DBSA Mental Health Screening Center These online screening tools are not ... you have any concerns, see your doctor or mental health professional. Depression This screening form was developed from ...

  17. Lung Cancer Screening

    Science.gov (United States)

    ... Treatment Lung Cancer Prevention Lung Cancer Screening Research Lung Cancer Screening (PDQ®)–Patient Version What is screening? Go ... These are called diagnostic tests . General Information About Lung Cancer Key Points Lung cancer is a disease in ...

  18. Skin Cancer Screening

    Science.gov (United States)

    ... Genetics of Skin Cancer Skin Cancer Screening Research Skin Cancer Screening (PDQ®)–Patient Version What is screening? ... These are called diagnostic tests . General Information About Skin Cancer Key Points Skin cancer is a disease ...

  19. Testicular Cancer Screening

    Science.gov (United States)

    ... Health Professional Testicular Cancer Treatment Testicular Cancer Screening Testicular Cancer Screening (PDQ®)–Patient Version What is screening? Go ... These are called diagnostic tests . General Information About Testicular Cancer Key Points Testicular cancer is a disease in ...

  20. Recent Advances in Biosensing With Photonic Crystal Surfaces: A Review.

    Science.gov (United States)

    Cunningham, B T; Zhang, M; Zhuo, Y; Kwon, L; Race, C

    2016-05-15

    Photonic crystal surfaces that are designed to function as wavelength-selective optical resonators have become a widely adopted platform for label-free biosensing, and for enhancement of the output of photon-emitting tags used throughout life science research and in vitro diagnostics. While some applications, such as analysis of drug-protein interactions, require extremely high resolution and the ability to accurately correct for measurement artifacts, others require sensitivity that is high enough for detection of disease biomarkers in serum with concentrations less than 1 pg/ml. As the analysis of cells becomes increasingly important for studying the behavior of stem cells, cancer cells, and biofilms under a variety of conditions, approaches that enable high resolution imaging of live cells without cytotoxic stains or photobleachable fluorescent dyes are providing new tools to biologists who seek to observe individual cells over extended time periods. This paper will review several recent advances in photonic crystal biosensor detection instrumentation and device structures that are being applied towards direct detection of small molecules in the context of high throughput drug screening, photonic crystal fluorescence enhancement as utilized for high sensitivity multiplexed cancer biomarker detection, and label-free high resolution imaging of cells and individual nanoparticles as a new tool for life science research and single-molecule diagnostics.

  1. 产酱香细菌GX-16的筛选及培养条件研究%Screening of the Bacteria Strain-GX-16 for Soysauce-like Aroma-producing and Research on Its Culture Condition

    Institute of Scientific and Technical Information of China (English)

    武思齐

    2011-01-01

    [目的]筛选贵州当地的产酱香细菌,并对其培养条件进行研究.[方法]从豆豉样品中分离菌株,制作种子液接种于黄豆培养基,发酵完成后,通过感官判定选取产酱香效果较好的菌株保存.选取发酵时间、培养基起始pH、培养温度作为培养条件,利用正交试验对这3个因素对菌株活力的影响进行研究.[结果]分离到产酱香菌株GX-16,培养时间对其生长活力影响最大,培养温度其次,培养基起始pH影响最小;GX-16菌株最佳培养条件为:以LB液体培养基作为种子液培养基,培养基起始pH为7.5,培养温度为35℃,在150r/min摇床中振荡培养24h.[结论]从贵州大方、黔西采取的豆豉样品中分离到产酱香菌株GX-16,为贵州产酱香细菌种质资源和产品开发及改良研究提供了参考.%[Objective] The bacteria strain form local area in Cuizhou and with the ability in the production of soysauce-like aroma was screened and its culture condition was studied. [ Method ] The bacteria strain was isolated from the fermented soybean product-Douchi, then fermented after it was inoculated in the soybean medium and finally the best one with the good effect on the production of soysauce-like aroma was preserved based on the sensory evaluation of strain sauce. The fermentation time, initial pH of medium, incubation temperature and other culture conditions was optimized through the orthogonal experiment. [ Result] The bacteria strain-GX-16 with best effect on the production of soysauce-like aroma was isolated. The order of the factor affecting the growth activity of the GX-16 was culture time > temperature > initial pH. The optimal culture condition of GX-16 strain culturing was: LB liquid medium was used as basic medium with the initial pH of 7.5, the temperature of 35 ℃ and shaking culture at 150 r/min for 24 hours. [ Conclusion] The reference for the development and improvement of soysauce-like aroma strain germ-plasm was provide

  2. THE INFLUENCE OF HEATINGTREATMENT CONDITION ON CRYSTALLIZATION SPECIES AND MORPHOLOGY OF LFP-GLASS%热处理气氛对LFP-玻璃析晶种类与形貌的影响

    Institute of Scientific and Technical Information of China (English)

    李晓生; 魏礼杰; 林蔚

    2012-01-01

    Making use of diagram to design ingredient; lithium obtained by melting method, The glass powers were mixed with nitric iron phosphate glass powers had been acid and heatingtreated under nitrogen condition to prepare LiFePO4/C composite, meanwhile, the changes of sample' s composition and morphology were also observed when glass powers were heatingtreated under nitrogen and air conditions. The sample Ts thermal property, composition, microstructure, element were analyzed by means of thermogravimetric analysis/ differential scanning calorimetry instrument, xray diffraction, scanning electron microscope, energy dispersive x-ray spectroscopy. The result illustrate that: Li3Fe2(PO4)3 and Fe203 were prepared when heating-treat glass under air condition; Li3Fe2(PO4)3 and LiFePQ are prepared when heatingteat glass under nitrogen conditiom LiFePO4/C composite is prepared when heatingtreat glass mixed nitric acid under nitrogen condition; Heating treatment condition has direct influence on the crystallization species and morohologv.%利用相图设计配方,采用熔融法制备LFP-玻璃(锂铁磷酸盐玻璃)粉末。将玻璃粉与柠檬酸混合,在氮气气氛中热处理制备LiFePO4/C复合材料,并考察玻璃在氮气气氛、空气气氛热处理时样品的组成与形貌变化。选用热重/差示扫描量热仪(TG/DSC)、X-射线衍射(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)对样品进行热性能分析、物相分析、微观形貌分析和元素成分分析。结果显示:玻璃粉在空气气氛中热处理获得Li3Fe2(PO4)3和Fe2O3。;玻璃粉在氮气条件下热处理获得Li3Fe2(PO4)5,与LiFePO4;玻璃粉与柠檬酸混合在氮气气氛中热处理获得LiFePO4/C复合材料;热处理气氛对LFP-玻璃析晶种类与形貌有直接影响。

  3. THE INFLUENCE OF SCREEN PARAMETERS ON PERFORMANCE CHARACTERISTICS

    Institute of Scientific and Technical Information of China (English)

    王汝林; A.C.Apling

    1996-01-01

    A series of laboratory screening tests have been performed with the objective of evaluating the effect of feed rate, screen length and screen motion on the quality of separation. The separation performance has been evaluated by the use of proposed ISO Standard measures which are based on the partition curve. The laboratory rig, the test programme and results derived from it are discussed. The effect of screen length, feed rate and screen motion on the levels of screen performance as indicated by these measures and a normalised separation size parameter are discussed in relation to the assumed screening conditions for the tests reported and conclusions are summarised.

  4. Timing and conditions of metamorphism and melt crystallization in Greater Himalayan rocks, eastern and central Bhutan: insight from U-Pb zircon and monazite geochronology and trace-element analyses

    Science.gov (United States)

    Zeiger, K.; Gordon, S. M.; Long, S. P.; Kylander-Clark, A. R. C.; Agustsson, K.; Penfold, M.

    2015-05-01

    Within the eastern Himalaya in central and eastern Bhutan, Greater Himalayan (GH) rocks are interpreted to have been thickened by the Kakhtang thrust (KT). In order to understand the metamorphic and exhumation history of the GH and to evaluate the structural significance of the KT, zircon and monazite from twenty samples were analyzed by laser-ablation split-stream ICPMS. In eastern Bhutan, zircon and monazite from samples collected in the KT hanging wall revealed ca. 36-28 Ma metamorphism. Subsequently, the initiation of melt crystallization shows a trend with structural distance above the KT, with early melt crystallization (ca. 27 Ma) in the structurally highest samples and younger melt crystallization (ca. 16 Ma) for leucosomes within the KT zone. Melt crystallization was protracted and continued until ca. 14-13 Ma in both the KT hanging wall and the footwall. In comparison, in central Bhutan, two leucosomes revealed extended melt crystallization from ca. 31 to 19 Ma. The youngest zircon dates from samples exposed structurally above and below the KT are similar, indicating that the KT was not as significant of a structure as other fault systems to which it has been correlated. However, the younging trend in the initiation of melt crystallization with decreasing structural distance above the KT argues that progressive underplating of ductile material assisted in the initial emplacement of the GH unit in central and eastern Bhutan. The KT likely represents a minor shear zone that aided in this underplating process.

  5. Responsible implementation of expanded carrier screening.

    Science.gov (United States)

    Henneman, Lidewij; Borry, Pascal; Chokoshvili, Davit; Cornel, Martina C; van El, Carla G; Forzano, Francesca; Hall, Alison; Howard, Heidi C; Janssens, Sandra; Kayserili, Hülya; Lakeman, Phillis; Lucassen, Anneke; Metcalfe, Sylvia A; Vidmar, Lovro; de Wert, Guido; Dondorp, Wybo J; Peterlin, Borut

    2016-06-01

    This document of the European Society of Human Genetics contains recommendations regarding responsible implementation of expanded carrier screening. Carrier screening is defined here as the detection of carrier status of recessive diseases in couples or persons who do not have an a priori increased risk of being a carrier based on their or their partners' personal or family history. Expanded carrier screening offers carrier screening for multiple autosomal and X-linked recessive disorders, facilitated by new genetic testing technologies, and allows testing of individuals regardless of ancestry or geographic origin. Carrier screening aims to identify couples who have an increased risk of having an affected child in order to facilitate informed reproductive decision making. In previous decades, carrier screening was typically performed for one or few relatively common recessive disorders associated with significant morbidity, reduced life-expectancy and often because of a considerable higher carrier frequency in a specific population for certain diseases. New genetic testing technologies enable the expansion of screening to multiple conditions, genes or sequence variants. Expanded carrier screening panels that have been introduced to date have been advertised and offered to health care professionals and the public on a commercial basis. This document discusses the challenges that expanded carrier screening might pose in the context of the lessons learnt from decades of population-based carrier screening and in the context of existing screening criteria. It aims to contribute to the public and professional discussion and to arrive at better clinical and laboratory practice guidelines.

  6. Responsible implementation of expanded carrier screening

    Science.gov (United States)

    Henneman, Lidewij; Borry, Pascal; Chokoshvili, Davit; Cornel, Martina C; van El, Carla G; Forzano, Francesca; Hall, Alison; Howard, Heidi C; Janssens, Sandra; Kayserili, Hülya; Lakeman, Phillis; Lucassen, Anneke; Metcalfe, Sylvia A; Vidmar, Lovro; de Wert, Guido; Dondorp, Wybo J; Peterlin, Borut

    2016-01-01

    This document of the European Society of Human Genetics contains recommendations regarding responsible implementation of expanded carrier screening. Carrier screening is defined here as the detection of carrier status of recessive diseases in couples or persons who do not have an a priori increased risk of being a carrier based on their or their partners' personal or family history. Expanded carrier screening offers carrier screening for multiple autosomal and X-linked recessive disorders, facilitated by new genetic testing technologies, and allows testing of individuals regardless of ancestry or geographic origin. Carrier screening aims to identify couples who have an increased risk of having an affected child in order to facilitate informed reproductive decision making. In previous decades, carrier screening was typically performed for one or few relatively common recessive disorders associated with significant morbidity, reduced life-expectancy and often because of a considerable higher carrier frequency in a specific population for certain diseases. New genetic testing technologies enable the expansion of screening to multiple conditions, genes or sequence variants. Expanded carrier screening panels that have been introduced to date have been advertised and offered to health care professionals and the public on a commercial basis. This document discusses the challenges that expanded carrier screening might pose in the context of the lessons learnt from decades of population-based carrier screening and in the context of existing screening criteria. It aims to contribute to the public and professional discussion and to arrive at better clinical and laboratory practice guidelines. PMID:26980105

  7. Crystal growth and properties of novel organic nonlinear optical crystals of 4-Nitrophenol urea

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, M. Krishna, E-mail: krishnamohan.m@ktr.srmuniv.ac.in; Ponnusamy, S.; Muthamizhchelvan, C.

    2017-07-01

    Single crystals of 4-Nitrophenol urea have been grown from water using slow evaporation technique at constant temperature, with the vision to improve the properties of the crystals. The unit cell parameters of the grown crystals were determined by single crystal and powder X-Ray diffraction. FTIR studies reveals the presence of different vibrational bands. The Optical studies confirmed that the crystal is transparent up to 360 nm .TGA and DSC studies were carried out to understand the thermal behavior of crystals. The SHG studies show the suitability of the crystals for NLO applications. The etching studies were carried out to study the behavior of the crystals under different conditions.These studies reveal that the crystals of 4-Nitrophenol urea are suitable for device applications. - Highlights: • 4-Nitrophenol urea crystals of dimensions 14 mm × 1 mm were grown. • UV–Visible studies indicate the crystal is transparent in the region of 370–800 nm. • Thermal studies show the crystal starts decomposing at 170 °C. • SHG studies indicate that the crystals have NLO efficiency 3.5 times that of KDP.

  8. Breast cancer screening: An outpatient clinic study

    Directory of Open Access Journals (Sweden)

    Mustafa Girgin

    2017-03-01

    Conclusion: A multidisciplinary cancer screening program should be maintained. With such a process, the aim is to reduce the morbidity and mortality of the disease without adversely affecting the health conditions of asymptomatic individuals based on the screening. Success is brought about by the combination of individual features. [Arch Clin Exp Surg 2017; 6(1.000: 23-27

  9. Screening of Lipase-Producing Bacteria and Conditions Optimization of Lipase Production by Citrobacter sp.%产脂肪酶菌株筛选及柠檬酸杆菌产酶条件优化

    Institute of Scientific and Technical Information of China (English)

    张晶晶; 刘金峰; 牟伯中; 杨世忠

    2015-01-01

    Lipase can catalyze hydrolysis of triglyceride into fatty acids and glycerol,and has been widely applied in industries,and to obtain lipase-producing microorganisms is the basis of the study. A novel lipase-producing microbe was isolated from lipid-contaminated soil samples using plate-screening method. It was purified and identified as Citrobacter sp. through 16S rRNA sequence analysis. The enzyme production condition was optimized by single factor experiment. The optimum culture condition in a liter medium was 2. 0(g/ L,the same below)of soluble starch,1. 0 KH2 PO4 ,2. 2 K2 HPO4 ·3H2 O,1. 0(NH4 )2 SO4 ,0. 1 MgSO4 ·7H2 O,2. 0 beef extract,olive oil 10. 0 mL,pH 7. 5 and 15 mL of inoculum,culture for 43 h at 37 °C in shaker. The obtained enzymatic activity was 384 U/ mL at the highest,and it was 13-fold of that before the optimization. This strain could be used to produce lipase.%脂肪酶可以催化甘油三酯水解成脂肪酸和甘油,已广泛应用在工业领域,而获得产酶微生物是研究的基础。采用油脂平板法筛选出1株脂肪酶产生菌。经16S rRNA 序列分析可知,该菌株属于柠檬酸杆菌(Citrobacter werkman and Gillen)。单因素试验对其进行产酶条件优化,优化后产酶条件(g/ L):淀粉2.0,KH2 PO41.0,K2 HPO4·3H2 O 2.2,(NH4)2 SO41.0,MgSO4·7H2 O 0.1,牛肉膏2.0,橄榄油10.0 mL,pH 7.5,每升接种量为15 mL,37℃培养43 h。获得最大酶活为384 U/ mL,是优化前的13倍。可以利用该菌制备脂肪酶。

  10. Screening of Dihydroxyacetone-producing Marine Bacteria and Optimization of the Fermentation Conditions%产二羟基丙酮的海洋菌筛选与发酵条件的优化

    Institute of Scientific and Technical Information of China (English)

    陈喆; 王兆守; 方柏山; 王世珍; 彭雅娟

    2011-01-01

    20 strains capable of producing dihydroxyacetone from glycerol were isolated from the soil of the mangrove in Xiamen harbor and one of which named ch20-l had relatively higher converting capability of 96.3%. The strain was identified by 16SrDNA sequence and systematic biochemical characteristics analysis. The results showed that the strain belongs to Flavobacterium. Plackett-Burman (PB) design and Central Composite Design (CCD) were applied to screen and optimize the fermentation conditions to produce DHA. The amount of CaCO3, and the concentrations of sorbitol and yeast extract, as three key factors, were found to significantly influence the yield of DHA PB design and the following statistic analysis. By CCD design and response surface analysis, the quadratic model for three significant factors was established with the yield of DHA as the target response. Under the optimal conditions, I.e., 30 hours of fermentation, the initial glycerol concentrations of 54g/L, 16.4g/L CaCO3, 12.7g/L yeast extract and 13.1g/L sorbitol ,the yield of DHA were 52.0 g/ L with 1.73 g/L.h-1 of production intensity.%对厦门海域红树林土壤进行菌种筛选,得到20株可将甘油转化为二羟基丙酮的菌株,其中ch20-1转化率较高,达到96.3%.对该菌株进行生理生化鉴定实验和16SrDNA基因分析表明,菌株为黄杆菌属(Flavobacterium).采用Plackett-Burman (PB)法和中心复合设计(Central Composite Design,CCD)法对该菌株进行发酵条件优化.PB实验设计与统计学分析表明:碳酸钙、山梨醇和酵母膏的浓度是影响DHA产量的三个关键因素.以DHA产量为响应目标,对三因素进行中心复合设计,并经响应面法优化分析得到了影响DHA产量的非线性模型,确定了发酵的最优培养基组成为:初始甘油浓度54.0g/L,碳酸钙浓度16.4g/L,酵母膏浓度为12.7g/L,山梨醇浓度13.1g/L.在最优条件下发酵30h,DHA产量达到52.0g/L,生产强度为1.73g/L.h-1.

  11. Screening and Culture Condition Optimizing of Microbe with High Flocculating Capability%高效絮凝剂产生菌的筛选及培养条件优化研究

    Institute of Scientific and Technical Information of China (English)

    易允燕; 叶劲松; 俞志敏; 卫新来; 吴克

    2016-01-01

    From soil and urban sewage treatment plant in the second pond sludge filter out high efficient flocculant,culture conditions,the table on the flocculation effect was studied for the application of high ef-ficient flocculant produced bacteria provide a theoretical basis.A strain was screened from soil and sludge,and named MBFS -17,which was identified as Bacillus and has the highest flocculating activity. Through the single factor and orthogonal experiment,it optimized the culture conditions and the results showed that sucrose is the best carbon source,fish peptone is the best nitrogen source.When the concen-tration of sucrose and fish peptone is 14 g/L, 0.5 g/L,temperature is 30 ℃,pH was 8,the bioflocculant was produced by MBFS -17 achieved the high flocculating activity which reached to 94.7%.The floccu-lant produced by the flocculant has a higher flocculation effect,and has great application prospect in the treatment of wastewater flocculation.%从土壤和城市生活污水处理厂二沉池污泥中筛选出高效絮凝剂产生菌,并研究培养条件对其产絮活性的影响,为高效絮凝剂产生菌的应用提供了理论依据。通过单因素和正交实验对絮凝剂产生菌菌株培养条件进行优化。结果共筛选出24株细菌,其中有明显絮凝活性的菌株共8株,经过复筛获得1株高效稳定絮凝剂产生菌,命名为 MBFS -17,经分子生物学鉴定此菌为芽孢杆菌。实验结果表明:MBFS -17菌株的最适碳源是蔗糖,最适氮源是鱼蛋白胨,在碳源浓度为14 g/L,氮源浓度为0.5 g/L,温度为30℃,pH 为8的条件下,MBFS -17菌株所产絮凝剂对高岭土悬浊液的絮凝率高达94.7%。筛选得到的絮凝剂产生菌经过培养基优化具有较高的絮凝效果,在废水絮凝处理中有较大的应用前景。

  12. Searching for the Best Protein Crystals: Synchrotron Based Measurements of Protein Crystal Quality

    Science.gov (United States)

    Borgstahl, Gloria; Snell, Edward H.; Bellamy, Henry; Pangborn, Walter; Nelson, Chris; Arvai, Andy; Ohren, Jeff; Pokross, Matt

    1999-01-01

    We are developing X-ray diffraction methods to quantitatively evaluate the quality of protein crystals. The ultimate use for these crystal quality will be to optimize crystal growth and freezing conditions to obtain the best diffraction data. We have combined super fine-phi slicing with highly monochromatic, low divergence synchrotron radiation and the ADSC Quantum 4 CCD detector at the Stanford Synchrotron Radiation laboratory beamline 1.5 to accurately measure crystal mosaicity. Comparisons of microgravity versus earth-grown insulin crystals using these methods will be presented.

  13. Stomach (Gastric) Cancer Screening

    Science.gov (United States)

    ... Gastric Cancer Treatment Stomach Cancer Prevention Stomach Cancer Screening Research Stomach (Gastric) Cancer Screening (PDQ®)–Patient Version What is ... from the . There is no standard or routine screening test for stomach cancer. Several types of screening tests have been ...

  14. Prenatal screening and genetics

    NARCIS (Netherlands)

    Alderson, P.; Aro, A.R.; Dragonas, T.; Ettorre, E.; Hemminki, E.; Jalinoja, P.; Santalahti, P.; Tijmstra, T.

    Although the term 'genetic screening' has been used for decades, this paper discusses how, in its most precise meaning, genetic screening has not yet been widely introduced. 'Prenatal screening' is often confused with 'genetic screening'. As we show, these terms have different meanings, and we

  15. Prenatal screening and genetics

    NARCIS (Netherlands)

    Alderson, P.; Aro, A.R.; Dragonas, T.; Ettorre, E.; Hemminki, E.; Jalinoja, P.; Santalahti, P.; Tijmstra, T.

    2001-01-01

    Although the term 'genetic screening' has been used for decades, this paper discusses how, in its most precise meaning, genetic screening has not yet been widely introduced. 'Prenatal screening' is often confused with 'genetic screening'. As we show, these terms have different meanings, and we exami

  16. Prenatal screening and genetics

    DEFF Research Database (Denmark)

    Alderson, P; Aro, A R; Dragonas, T

    2001-01-01

    Although the term 'genetic screening' has been used for decades, this paper discusses how, in its most precise meaning, genetic screening has not yet been widely introduced. 'Prenatal screening' is often confused with 'genetic screening'. As we show, these terms have different meanings, and we ex...

  17. Antibacterial, antibiofilm and antioxidant screening of copper(II)-complexes with some S-alkyl derivatives of thiosalicylic acid. Crystal structure of the binuclear copper(II)-complex with S-propyl derivative of thiosalicylic acid

    Science.gov (United States)

    Bukonjić, Andriana M.; Tomović, Dušan Lj.; Nikolić, Miloš V.; Mijajlović, Marina Ž.; Jevtić, Verica V.; Ratković, Zoran R.; Novaković, Slađana B.; Bogdanović, Goran A.; Radojević, Ivana D.; Maksimović, Jovana Z.; Vasić, Sava M.; Čomić, Ljiljana R.; Trifunović, Srećko R.; Radić, Gordana P.

    2017-01-01

    The spectroscopically predicted structure of the obtained copper(II)-complex with S-propyl derivative of thiosalicylic acid was confirmed by X-ray structural study. The binuclear copper(II)-complex with S-propyl derivative of thiosalicylic acid crystallized in two polymorphic forms with main structural difference in the orientation of phenyl rings relative to corresponding carboxylate groups. The antibacterial activity was tested determining the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) by using microdilution method. The influence on bacterial biofilm formation was determined by tissue culture plate method. In general, the copper(II)-complexes manifested a selective and moderate activity. The most sensitive bacteria to the effects of Cu(II)-complexes was a clinical isolate of Pseudomonas aeruginosa. For this bacteria MIC and biofilm inhibitory concentration (BIC) values for all tested complexes were in the range or better than the positive control, doxycycline. Also, for the established biofilm of clinical isolate Staphylococcus aureus, BIC values for the copper(II)-complex with S-ethyl derivative of thiosalicylic acid,[Cu2(S-et-thiosal)4(H2O)2] (C3) and copper(II)-complex with S-butyl derivative of thiosalicylic acid, [Cu2(S-bu-thiosal)4(H2O)2] (C5) were in range or better than the positive control. All the complexes acted better against Gram-positive bacteria (Staphylococcus aureus and Staphylococcus aureus ATCC 25923) than Gram-negative bacteria (Proteus mirabilis ATCC 12453, Pseudomonas aeruginosa, and P. aeruginosa ATCC 27855). The complexes showed weak antioxidative properties tested by two methods (1,1-diphenyl-2-picrylhydrazyl (DPPH) and reducing power assay).

  18. High-efficiency screening of monoclonal antibodies for membrane protein crystallography.

    Directory of Open Access Journals (Sweden)

    Hyun-Ho Lim

    Full Text Available Determination of crystal structures of membrane proteins is often limited by difficulties obtaining crystals diffracting to high resolution. Co-crystallization with Fab fragments of monoclonal antibodies has been reported to improve diffraction of membrane proteins crystals. However, it is not simple to generate useful monoclonal antibodies for membrane protein crystallography. In this report, we present an optimized process for efficient screening from immunization to final validation of monoclonal antibody for membrane protein crystallography.

  19. Ribbon crystals.

    Directory of Open Access Journals (Sweden)

    Jakob Bohr

    Full Text Available A repetitive crystal-like pattern is spontaneously formed upon the twisting of straight ribbons. The pattern is akin to a tessellation with isosceles triangles, and it can easily be demonstrated with ribbons cut from an overhead transparency. We give a general description of developable ribbons using a ruled procedure where ribbons are uniquely described by two generating functions. This construction defines a differentiable frame, the ribbon frame, which does not have singular points, whereby we avoid the shortcomings of the Frenet-Serret frame. The observed spontaneous pattern is modeled using planar triangles and cylindrical arcs, and the ribbon structure is shown to arise from a maximization of the end-to-end length of the ribbon, i.e. from an optimal use of ribbon length. The phenomenon is discussed in the perspectives of incompatible intrinsic geometries and of the emergence of long-range order.

  20. Crystallization process

    Science.gov (United States)

    Adler, Robert J.; Brown, William R.; Auyang, Lun; Liu, Yin-Chang; Cook, W. Jeffrey

    1986-01-01

    An improved crystallization process is disclosed for separating a crystallizable material and an excluded material which is at least partially excluded from the solid phase of the crystallizable material obtained upon freezing a liquid phase of the materials. The solid phase is more dense than the liquid phase, and it is separated therefrom by relative movement with the formation of a packed bed of solid phase. The packed bed is continuously formed adjacent its lower end and passed from the liquid phase into a countercurrent flow of backwash liquid. The packed bed extends through the level of the backwash liquid to provide a drained bed of solid phase adjacent its upper end which is melted by a condensing vapor.

  1. [Screening saliva].

    Science.gov (United States)

    Deutsch, O; Palmon, A; Aframian, D J

    2013-04-01

    Oral Fluids (OF) are a complex mixture including components deriving from, salivary glands, blood, nasal and bronchial secretions, mucosal lining cells and microbiota. Therefore, OF as a mirror of the body, were suggested as an important diagnostic fluid for the detection of both, oral and systemic diseases. OF as diagnostic fluids have several advantages; their collection is easy, inexpensive and noninvasive, they are suitable for home use and for epidemiology researches, they are easy to store and ship, do not clot and enable fast detection. OF based diagnostics research accomplished a great advance during the last decade. This is mainly due to biotechnology improvements such as 2-D Fluorescence Difference Gel Electrophoresis, quantitative Mass Spectrometry and bioinformatics systems. These technologies enabled the detection of more than 3000 proteins in oral fluids, as well as the establishment of a panel of biomarkers to different human pathological conditions (i.e. periodontitis, Sjögren's Syndrome, oral cancer, pancreatic cancer etc). However, this diagnostic field has several drawbacks, mainly due to oral fluids variance composition, blood contamination as a result of gingivitis or mucosal injuries, the lack of a single established collection protocol and the presence of high abundant components in OF. This article summarizes the current research, and provides an outlook toward the foundation of this unique body fluid as a major player in the diagnostic field.

  2. Screening for abdominalt aortaaneurisme

    DEFF Research Database (Denmark)

    Lindholt, J S; Juul, Svend; Henneberg, E W;

    1997-01-01

    rupture. Ultrasonographic screening for AAA takes 10 minutes per scan, and the sensitivity and specificity are high. Ultrasonographic screening for AAA is a reliable, safe and inexpensive method for screening, and screening for AAA is discussed worldwide. One point four percent of deaths among men from 65...... on uncertain assumptions concerning prevalence, incidence and risk of rupture. Therefore a randomized trial screening of 65-73 year old males is taking place in the County of Viborg in Denmark. Udgivelsesdato: 1997-Mar-24...

  3. Screening for abdominalt aortaaneurisme

    DEFF Research Database (Denmark)

    Lindholt, Jes Sanddal; Juul, Søren; Henneberg, E W;

    1997-01-01

    rupture. Ultrasonographic screening for AAA takes 10 minutes per scan, and the sensitivity and specificity are high. Ultrasonographic screening for AAA is a reliable, safe and inexpensive method for screening, and screening for AAA is discussed worldwide. One point four percent of deaths among men from 65...... on uncertain assumptions concerning prevalence, incidence and risk of rupture. Therefore a randomized trial screening of 65-73 year old males is taking place in the County of Viborg in Denmark....

  4. Discrete breathers in crystals

    Science.gov (United States)

    Dmitriev, S. V.; Korznikova, E. A.; Baimova, Yu A.; Velarde, M. G.

    2016-05-01

    It is well known that periodic discrete defect-containing systems, in addition to traveling waves, support vibrational defect-localized modes. It turned out that if a periodic discrete system is nonlinear, it can support spatially localized vibrational modes as exact solutions even in the absence of defects. Since the nodes of the system are all on equal footing, it is only through the special choice of initial conditions that a group of nodes can be found on which such a mode, called a discrete breather (DB), will be excited. The DB frequency must be outside the frequency range of the small-amplitude traveling waves. Not resonating with and expending no energy on the excitation of traveling waves, a DB can theoretically conserve its vibrational energy forever provided no thermal vibrations or other perturbations are present. Crystals are nonlinear discrete systems, and the discovery in them of DBs was only a matter of time. It is well known that periodic discrete defect-containing systems support both traveling waves and vibrational defect-localized modes. It turns out that if a periodic discrete system is nonlinear, it can support spatially localized vibrational modes as exact solutions even in the absence of defects. Because the nodes of the system are all on equal footing, only a special choice of the initial conditions allows selecting a group of nodes on which such a mode, called a discrete breather (DB), can be excited. The DB frequency must be outside the frequency range of small-amplitude traveling waves. Not resonating with and expending no energy on the excitation of traveling waves, a DB can theoretically preserve its vibrational energy forever if no thermal vibrations or other perturbations are present. Crystals are nonlinear discrete systems, and the discovery of DBs in them was only a matter of time. Experimental studies of DBs encounter major technical difficulties, leaving atomistic computer simulations as the primary investigation tool. Despite

  5. Crystal structure of 4-benzylcarbamoyl-1-methylpyridin-1-ium iodide: an efficient multimodal antiviral drug

    Directory of Open Access Journals (Sweden)

    T. N. Drebushchak

    2017-07-01

    Full Text Available In the title compound, [MeC5H4NCONHCH2C6H5]I or C14H15N2O+·I−, a cation and an anion form an ionic pair linked by a strong N—H...I hydrogen bond. In the crystal, ionic pairs linked by weak C—H...I hydrogen bonds form infinite ribbons along the crystallographic a axis. Polymorphism screening varying crystallization solvents (water, acetone 90%–water, ethanol 90%–water, 2-propanol 90%–water, DMF, DMSO, methanol, acetonitrile and conditions (solution temperature, heating and cooling protocols did not reveal any other polymorphs than the one reported in this work.

  6. Macromolecular Crystallization with Microfluidic Free-Interface Diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Segelke, B

    2005-02-24

    Fluidigm released the Topaz 1.96 and 4.96 crystallization chips in the fall of 2004. Topaz 1.96 and 4.96 are the latest evolution of Fluidigm's microfluidics crystallization technologies that enable ultra low volume rapid screening for macromolecular crystallization. Topaz 1.96 and 4.96 are similar to each other but represent a major redesign of the Topaz system and have of substantially improved ease of automation and ease of use, improved efficiency and even further reduced amount of material needed. With the release of the new Topaz system, Fluidigm continues to set the standard in low volume crystallization screening which is having an increasing impact in the field of structural genomics, and structural biology more generally. In to the future we are likely to see further optimization and increased utility of the Topaz crystallization system, but we are also likely to see further innovation and the emergence of competing technologies.

  7. Risks of Esophageal Cancer Screening

    Science.gov (United States)

    ... Esophageal Cancer Prevention Esophageal Cancer Screening Research Esophageal Cancer Screening (PDQ®)–Patient Version What is screening? Go to ... the esophagus and the stomach). Being overweight . Esophageal Cancer Screening Key Points Tests are used to screen for ...

  8. Coulomb screening in linear coasting nucleosynthesis

    CERN Document Server

    Singh, Parminder

    2015-01-01

    We investigate the impact of coulomb screening on primordial nucleosynthesis in a universe having scale factor that evolves linearly with time. Coulomb screening affects primordial nucleosynthesis via enhancement of thermonuclear reaction rates. This enhancement is determined by the solving Poisson equation within the context of mean field theory (under appropriate conditions during the primordial nucleosynthesis). Using these results, we claim that the mean field estimates of coulomb screening hardly affect the predicted element abundances and nucleosynthesis parameters$, \\{\\eta_9,\\xi_e\\}$. The deviations from mean field estimates are also studied in detail by boosting genuine screening results with the screening parameter ($\\omega_s$). These deviations show negligible effect on the element abundances and on nucleosynthesis parameters. This work thus rules out the coulomb screening effects on primordial nucleosynthesis in slow evolving models and confirms that constraints in ref.[7] on nucleosynthesis parame...

  9. Screening and Fermentation Conditions of the Cold-active Protease Marine Strain%产低温蛋白酶海洋细菌的筛选及发酵条件

    Institute of Scientific and Technical Information of China (English)

    郭艾英; 凌云; 张志雯

    2011-01-01

    Through preliminary petri-dish and following shaking flask fermentation screening,Strain HYM-16 producing higher protease was isolated from samples in Qinhuangdao of Bohai Sea located at 39°93′ N and 119°60′ E,and was primarily identified as Xanthobacter sp.Its fermentation condition was studied through the single-factor and orthogonal experiment.The results demonstrated that after 48 hours at 25 ℃ it had the maximum protease activity with 1% inoculation size and the stirring speed at 180 r/min,when 50 mL liquid culture in 250 mL flask.The optimal carbon and nitrogen source was saccharose and soybean flour respectively.Magnesium was beneficial to enzyme activity obviously.By using orthogonal experiment L9(34),the top-seeded formula for the media(g/L) was obtained: saccharose 1,soybean flour 20,Mg2+ 0.4,dipotassium hydrogen phosphate 0.5,and potassium dihydrogen phosphate 0.5.Finally,the optimized fermentation medium was validated,and the total activity of protesae was 605.8 U·mL-1,which was 46.9% higher than basic medium.%采用平板初筛和摇瓶复筛等方法,从渤海秦皇岛海域的海水样品中筛选到产低温蛋白酶活力较高的菌株HYM-16,初步鉴定为黄色杆菌属,设计单因素和正交试验,确定该菌的最佳发酵条件。结果表明,在装液量50 mL液体培养基的250 mL三角瓶中,以体积分数0.01的接种量、摇床转速180 r/min条件下,25℃培养48 h酶活最高;最适碳源、氮源分别为蔗糖、豆饼粉,Mg2+显著提高产酶量;采用L9(34)正交试验得最适发酵培养基配方:蔗糖1 g/L,豆饼粉20 g/L,MgCl2 0.4 g/L,K2HPO4 0.5 g/L,KH2PO4 0.5 g/L。经验证,优化后的发酵培养基菌株酶活达605.8×103 U.L-1,较基础培养基提高了46.9%。

  10. Screening conditions of adventitious bud induction and plantlet regeneration for Cunninghamia lanceolata%杉木茎段不定芽诱导及植株再生条件筛选

    Institute of Scientific and Technical Information of China (English)

    莫雅芳; 戴勤; 谭玲; 苏治南; 卢亮; 杨梅

    2013-01-01

    [目的]探索广西杉木快繁技术,为杉木组织培养和种苗供应提供参考依据.[方法]以杉木优良树种基部枝条为试验材料,进行茎段外植体消毒、不定芽诱导及植株再生研究.[结果]以75%酒精处理30 s+0.1%升汞消毒6min的效果较理想,污染率为30%;初代培养基为1/2MS+NAA 0.2 mg/L+6-BA 0.6 mg/L,第8d即有芽萌动,诱导率可达47%;继代培养基1/2MS +IBA 0.3 mg/L+6-BA 0.4 mg/L中加入蔗糖30 g/L,25 d腋芽增殖倍数可达3.4倍;1/4MS+IBA 0.15mg/L+NAA 0.075 mg/L对杉木生根诱导效果较好,生根率为52%.[结论],杉木外植体用75%酒精和0.1%升汞消毒6min效果较理想,适当减少培养基中矿质元素有利于杉木外殖体芽的诱导和试管苗的增殖生长,NAA可促进试管苗生根.%[Objective]Conditions of the adventitious bud induction and plant regeneration for Cunninghamia lanceolata were screened and rapid propagation techniques for Chinese fir in Guangxi was explored to provide references for supply and tissue culture of Chinese fir seedlings.[Method]Using base branches of superior Chinese fir species as testing materials,stem explant disinfection,adventitious bud induction and plant regeneration were the focal points in the current research.[Result] (1)The best disinfection method was treating stem explants with 75% ethanol for 30 s and 0.1% mercuric chloride for 6 min,which showed 30% contamination rate; (2)In the initial medium (1/2MS + NAA 0.2 mg/L + 6-BA 0.6 mg/L),the buds germinated on the 8th day with the induction rate of 47%; (3)In the optimum subculture medium (1/2MS + IBA 0.3 mg/L + 6-BA 0.6 mg/L + white sugar 30 g/L),axillary buds were multiplied by 3.4 times on the 25th day; (4)The induction effect was the best with the rooting rate of 52% in the rooting medium (1/4MS + IBA 0.15 mg/L + NAA 0.075 mg/L).[Conclusion]It was beneficial to the adventitious bud induction for Chinese fir with the initial medium (1/2MS + NAA 0.2 mg

  11. Effect of temperature on the evolution of bright and dark screening-photovoltaic spatial solitons

    Institute of Scientific and Technical Information of China (English)

    刘劲松; 郝中华

    2002-01-01

    We investigate theoretically the temperature effects on the evolution of both bright and dark screening-photovoltaicoptical spatial solitons in biased photovoltaic-photorefractive crystals in the case of neglecting the diffusion process. Fora stable bright or dark screening-photovoltaic soliton originally formed in a crystal at a given temperature, when thecrystal temperature changes, it will evolve into another stable screening-photovoltaic soliton if the change is quite small,whereas it will become unstable or break down if the temperature change is large enough. The spatial shape of a stablescreening-photovoltaic soliton can be reshaped by appropriately adjusting the crystal temperature.

  12. Unique interactive projection display screen

    Energy Technology Data Exchange (ETDEWEB)

    Veligdan, J.T.

    1997-11-01

    Projection systems continue to be the best method to produce large (1 meter and larger) displays. However, in order to produce a large display, considerable volume is typically required. The Polyplanar Optic Display (POD) is a novel type of projection display screen, which for the first time, makes it possible to produce a large projection system that is self-contained and only inches thick. In addition, this display screen is matte black in appearance allowing it to be used in high ambient light conditions. This screen is also interactive and can be remotely controlled via an infrared optical pointer resulting in mouse-like control of the display. Furthermore, this display need not be flat since it can be made curved to wrap around a viewer as well as being flexible.

  13. Protein crystallization: from HTS to kilogram-scale.

    Science.gov (United States)

    Klyushnichenko, Vadim

    2003-11-01

    The first experiments on protein crystallization started randomly during the 19th century. This technique has been widely used for the determination of the tertiary structure of proteins since the 1950s, when an understanding of the physics of protein crystallization began to emerge. In the 1980s and 1990s, research focused on the study of protein crystal growth processes in microgravity environments, which were created in space shuttle experiments. High-throughput screening (HTS) systems were developed that later found broader laboratory applications. The combination of HTS with an engineering approach opens new opportunities for the protein crystallization process to become a robust, scalable, reproducible and economically viable industrial unit operation.

  14. Routine screening for postpartum depression.

    Science.gov (United States)

    Georgiopoulos, A M; Bryan, T L; Wollan, P; Yawn, B P

    2001-02-01

    Postpartum depression (PPD) is a common and often overlooked condition. Validated screening tools for PPD exist but are not commonly used. We present the 1-year outcome of a project to implement universal PPD screening at the 6-week postpartum visit. Universal screening with the Edinburgh Postnatal Depression Scale (EPDS) was implemented in all community postnatal care sites. One-year outcome assessments (diagnosis and treatment of PPD) were completed for a sample of the women screened using medical record review of all care they received during the first year postpartum. Sixty-eight (20%) of the 342 women whose medical records were reviewed had been given a documented diagnosis of postpartum depression, resulting in an estimated population rate of 10.7%. Depression was diagnosed in 35% of the women with elevated EPDS scores (> or =10) compared with 5% of the women with low EPDS scores (<10) in the first year postpartum. Treatment was provided for all women diagnosed with depression, including drug therapy for 49% and counseling for 78%. Four women were hospitalized for depression. Some degree of suicidal ideation was noted on the EPDS by 48 women but acknowledged in the chart of only 10 women, including 1 with an immediate hospitalization. The rate of diagnosis of postpartum depression in this community increased from 3.7% before the routine use of EPDS screening to 10.7% following screening. A high EPDS score was predictive of a diagnosis of postpartum depression, and the implementation of routine EPDS screening at 6 weeks postpartum was associated with an increase in the rate of diagnosed postpartum depression in this community.

  15. Stirred batch crystallization of a therapeutic antibody fragment.

    Science.gov (United States)

    Hebel, Dirk; Huber, Sabine; Stanislawski, Bernd; Hekmat, Dariusch

    2013-07-20

    Technical-scale crystallization of therapeutic proteins may not only allow for a significant cost-reduction in downstream processing, but also enable new applications, e.g., the use of crystal suspensions for subcutaneous drug delivery. In this work, the crystallization of the antigen-binding fragment FabC225 was studied. First, vapor diffusion crystallization conditions from the literature were transferred to 10μL-scale microbatch experiments. A phase diagram was developed in order to identify the crystallization window. The conditions obtained from the microbatch experiments were subsequently transferred to parallelized 5mL-scale stirred-tank crystallizers. This scalable and reproducible agitated crystallization system allowed for an optimization of the crystallization process based on quantitative measurements. The optimized crystallization process resulted in an excellent yield of 99% in less than 2h by increasing the concentration of the crystallization agent ammonium sulfate during the process. The successful scalability of the Fab fragment crystallization process to 100mL-scale crystallizers based on geometric similarity was demonstrated. A favorable crystal size distribution was obtained. Furthermore, a wash step was introduced in order to remove unfavorable low-molecular substances from the crystals.

  16. Purification, crystallization, and properties of F1-ATPase complexes from the thermoalkaliphilic Bacillus sp. strain TA2.A1.

    Science.gov (United States)

    Stocker, Achim; Keis, Stefanie; Cook, Gregory M; Dimroth, Peter

    2005-11-01

    Recently, we reported the cloning of the atp operon encoding for the F(1)F(0)-ATP synthase from the extremely thermoalkaliphilic bacterium Bacillus sp. strain TA2.A1. In this study, the genes encoding the F(1) moiety of the enzyme complex were cloned from the atp operon into the vector pTrc99A and expressed in Escherichia coli in two variant complexes, F(1)-wt consisting of subunits alpha(3)beta(3)gammadeltaepsilon and F(1)Deltadelta lacking the entire delta-subunit as a prerequisite for overproduction and crystallization trials. Both F(1)-wt and F(1)Deltadelta were successfully overproduced in E. coli and purified in high yield and purity. F(1)Deltadelta was crystallized by micro-batch screening yielding three-dimensional crystals that diffracted to a resolution of 3.1A using a synchrotron radiation source. After establishing cryo and dehydrating conditions, a complete set of diffraction data was collected from a single crystal. No crystals were obtained with F(1)-wt. Data processing of diffraction patterns showed that F(1)Deltadelta crystals belong to the orthorhombic space group P2(1)2(1)2(1) with unit cell parameters of a=121.70, b=174.80, and c=223.50A, alpha, beta, gamma=90.000. The asymmetric unit contained one molecule of bacterial F(1)Deltadelta with a corresponding volume per protein weight (V(M)) of 3.25A(3) Da(-1) and a solvent content of 62.1%. Silver staining of single crystals of F(1)Deltadelta analyzed by SDS-PAGE revealed four bands alpha, beta, gamma, and epsilon with identical M(r)-values as those found in the native F(1)F(0)-ATP synthase isolated from strain TA2.A1 membranes. ATPase assays of F(1)Deltadelta crystals exhibited latent ATP hydrolytic activity that was highly stimulated by lauryldimethylamine oxide, a hallmark of the native enzyme.

  17. An ice crystal model for jupiter's moon Europa

    DEFF Research Database (Denmark)

    Dahl-Jensen, Dorthe; schmidt, Karen Guldbae

    2003-01-01

    A simple model for crystal growth in the ice shell of Europa has been made in order to estimate the size of ice crystals at Europa's surface. If mass is lost from the surface of Europa due to sputtering processes, and the ice thickness is constant in time, ice crystals will be transported upwards...... in the ice shell. The crystals will therefore grow under varying conditions through the shell.The model predicts that ice crystals are 4 cm-80 m across at the surface. For the preferred parameter values, a crystal size of the order of 7 m is calculated. Udgivelsesdato: 1 june...

  18. Binary colloidal crystals

    NARCIS (Netherlands)

    Christova-Zdravkova, C.G.

    2005-01-01

    Binary crystals are crystals composed of two types of particles having different properties like size, mass density, charge etc. In this thesis several new approaches to make binary crystals of colloidal particles that differ in size, material and charge are reported We found a variety of crystal st

  19. Population screening in hereditary hemochromatosis.

    Science.gov (United States)

    Motulsky, A G; Beutler, E

    2000-01-01

    Hemochromatosis is a common autosomal recessive condition found in the homozygous state in 1/200-1/400 people of northern-, central-, and western-European origin. It causes increased iron storage, which may lead to liver cirrhosis, liver cancer, heart disease, arthritis, and diabetes in many but not all affected adults, with a higher frequency in males. The condition is easily treated by repeated venesections without side effects but is frequently overlooked. Population screening of adults using iron indices alone or combined with DNA testing has therefore been recommended, but a consensus conference in 1997 recommended that such screening be deferred, owing to uncertainty regarding the extent of clinical disease that may develop in individuals detected by such programs. There was also concern that DNA screening results might be used for discrimination in insurance and occupational settings. Screening family members of patients with evidence of definite iron loading, however, is accepted by all observers. Because serious complications may be overlooked, a more aggressive stance toward case detection in the adult population has been advocated by some observers, realizing that unnecessary treatment might occur. Because additional information regarding the spectrum of clinical disease in homozygotes in now accumulating, a consensus conference in the near future is suggested to consider appropriate policies.

  20. Mixed crystal organic scintillators

    Science.gov (United States)

    Zaitseva, Natalia P; Carman, M Leslie; Glenn, Andrew M; Hamel, Sebastien; Hatarik, Robert; Payne, Stephen A; Stoeffl, Wolfgang

    2014-09-16

    A mixed organic crystal according to one embodiment includes a single mixed crystal having two compounds with different bandgap energies, the organic crystal having a physical property of exhibiting a signal response signature for neutrons from a radioactive source, wherein the signal response signature does not include a significantly-delayed luminescence characteristic of neutrons interacting with the organic crystal relative to a luminescence characteristic of gamma rays interacting with the organic crystal. According to one embodiment, an organic crystal includes bibenzyl and stilbene or a stilbene derivative, the organic crystal having a physical property of exhibiting a signal response signature for neutrons from a radioactive source.

  1. Hearing Loss: Screening Newborns

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Hearing Loss Screening Newborns Past Issues / Spring 2015 Table of ... of newborns in the U.S. are screened for hearing loss before they leave the hospital. Research improves the ...

  2. Cervical Cancer Screening

    Science.gov (United States)

    ... Cancer found early may be easier to treat. Cervical cancer screening is usually part of a woman's health ... may do more tests, such as a biopsy. Cervical cancer screening has risks. The results can sometimes be ...

  3. Screening for Cervical Cancer

    Science.gov (United States)

    Understanding Task Force Recommendations Screening for Cervical Cancer The U.S. Preventive Services Task Force (Task Force) has issued final recommendations on Screening for Cervical Cancer . These recommendations are for women ...

  4. Screening for Ovarian Cancer

    Science.gov (United States)

    Understanding Task Force Recommendations Screening for Ovarian Cancer The U.S. Preventive Services Task Force (Task Force) has issued a final recommendation on Screening for Ovarian Cancer . This recommendation is for ...

  5. Video Screen Capture Basics

    Science.gov (United States)

    Dunbar, Laura

    2014-01-01

    This article is an introduction to video screen capture. Basic information of two software programs, QuickTime for Mac and BlueBerry Flashback Express for PC, are also discussed. Practical applications for video screen capture are given.

  6. Prostate Cancer Screening

    Science.gov (United States)

    ... a man's bladder that produces fluid for semen. Cancer screening is looking for cancer before you have any ... as an ultrasound, MRI, or a biopsy. Prostate cancer screening has risks: Finding prostate cancer may not improve ...

  7. Endometrial Cancer Screening

    Science.gov (United States)

    ... Transvaginal ultrasound Endometrial sampling Tests are used to screen for different types of cancer. Some screening tests ... endometrium by inserting a brush, curette , or thin, flexible tube through the cervix and into the uterus. ...

  8. Screening for Glaucoma

    Science.gov (United States)

    Understanding Task Force Recommendations Screening for Glaucoma The U.S. Preventive Services Task Force (Task Force) has issued a final recommendation statement on Screening for Glaucoma . This final recommendation statement ...

  9. Nanoscale size effects in crystallization of metallic glass nanorods.

    Science.gov (United States)

    Sohn, Sungwoo; Jung, Yeonwoong; Xie, Yujun; Osuji, Chinedum; Schroers, Jan; Cha, Judy J

    2015-09-01

    Atomistic understanding of crystallization in solids is incomplete due to the lack of appropriate materials and direct experimental tools. Metallic glasses possess simple metallic bonds and slow crystallization kinetics, making them suitable to study crystallization. Here, we investigate crystallization of metallic glass-forming liquids by in-situ heating metallic glass nanorods inside a transmission electron microscope. We unveil that the crystallization kinetics is affected by the nanorod diameter. With decreasing diameters, crystallization temperature decreases initially, exhibiting a minimum at a certain diameter, and then rapidly increases below that. This unusual crystallization kinetics is a consequence of multiple competing factors: increase in apparent viscosity, reduced nucleation probability and enhanced heterogeneous nucleation. The first two are verified by slowed grain growth and scatter in crystallization temperature with decreasing diameters. Our findings provide insight into relevant length scales in crystallization of supercooled metallic glasses, thus offering accurate processing conditions for predictable metallic glass nanomolding.

  10. Crystallization of a pentapeptide-repeat protein by reductive cyclic pentylation of free amines with glutaraldehyde

    Energy Technology Data Exchange (ETDEWEB)

    Vetting, Matthew W., E-mail: vetting@aecom.yu.edu; Hegde, Subray S.; Blanchard, John S. [Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 (United States)

    2009-05-01

    A method to modify proteins with glutaraldehyde under reducing conditions is presented. Treatment with glutaraldehyde and dimethylaminoborane was found to result in cyclic pentylation of free amines and facilitated the structural determination of a protein previously recalcitrant to the formation of diffraction quality crystals. The pentapeptide-repeat protein EfsQnr from Enterococcus faecalis protects DNA gyrase from inhibition by fluoroquinolones. EfsQnr was cloned and purified to homogeneity, but failed to produce diffraction-quality crystals in initial crystallization screens. Treatment of EfsQnr with glutaraldehyde and the strong reducing agent borane–dimethylamine resulted in a derivatized protein which produced crystals that diffracted to 1.6 Å resolution; their structure was subsequently determined by single-wavelength anomalous dispersion. Analysis of the derivatized protein using Fourier transform ion cyclotron resonance mass spectrometry indicated a mass increase of 68 Da per free amino group. Electron-density maps about a limited number of structurally ordered lysines indicated that the modification was a cyclic pentylation of free amines, producing piperidine groups.

  11. Pressure cryocooling protein crystals

    Science.gov (United States)

    Kim, Chae Un; Gruner, Sol M.

    2011-10-04

    Preparation of cryocooled protein crystal is provided by use of helium pressurizing and cryocooling to obtain cryocooled protein crystal allowing collection of high resolution data and by heavier noble gas (krypton or xenon) binding followed by helium pressurizing and cryocooling to obtain cryocooled protein crystal for collection of high resolution data and SAD phasing simultaneously. The helium pressurizing is carried out on crystal coated to prevent dehydration or on crystal grown in aqueous solution in a capillary.

  12. Colorectal cancer screening.

    Science.gov (United States)

    Burt, Randall W; Cannon, Jamie A; David, Donald S; Early, Dayna S; Ford, James M; Giardiello, Francis M; Halverson, Amy L; Hamilton, Stanley R; Hampel, Heather; Ismail, Mohammad K; Jasperson, Kory; Klapman, Jason B; Lazenby, Audrey J; Lynch, Patrick M; Mayer, Robert J; Ness, Reid M; Provenzale, Dawn; Rao, M Sambasiva; Shike, Moshe; Steinbach, Gideon; Terdiman, Jonathan P; Weinberg, David; Dwyer, Mary; Freedman-Cass, Deborah

    2013-12-01

    Mortality from colorectal cancer can be reduced by early diagnosis and by cancer prevention through polypectomy. These NCCN Guidelines for Colorectal Cancer Screening describe various colorectal screening modalities and recommended screening schedules for patients at average or increased risk of developing colorectal cancer. In addition, the guidelines provide recommendations for the management of patients with high-risk colorectal cancer syndromes, including Lynch syndrome. Screening approaches for Lynch syndrome are also described.

  13. Screening for Lung Cancer

    Science.gov (United States)

    Mazzone, Peter J.; Naidich, David P.; Bach, Peter B.

    2013-01-01

    Background: Lung cancer is by far the major cause of cancer deaths largely because in the majority of patients it is at an advanced stage at the time it is discovered, when curative treatment is no longer feasible. This article examines the data regarding the ability of screening to decrease the number of lung cancer deaths. Methods: A systematic review was conducted of controlled studies that address the effectiveness of methods of screening for lung cancer. Results: Several large randomized controlled trials (RCTs), including a recent one, have demonstrated that screening for lung cancer using a chest radiograph does not reduce the number of deaths from lung cancer. One large RCT involving low-dose CT (LDCT) screening demonstrated a significant reduction in lung cancer deaths, with few harms to individuals at elevated risk when done in the context of a structured program of selection, screening, evaluation, and management of the relatively high number of benign abnormalities. Whether other RCTs involving LDCT screening are consistent is unclear because data are limited or not yet mature. Conclusions: Screening is a complex interplay of selection (a population with sufficient risk and few serious comorbidities), the value of the screening test, the interval between screening tests, the availability of effective treatment, the risk of complications or harms as a result of screening, and the degree with which the screened individuals comply with screening and treatment recommendations. Screening with LDCT of appropriate individuals in the context of a structured process is associated with a significant reduction in the number of lung cancer deaths in the screened population. Given the complex interplay of factors inherent in screening, many questions remain on how to effectively implement screening on a broader scale. PMID:23649455

  14. Computational Strain Gradient Crystal Plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2011-01-01

    A model for strain gradient crystal visco-plasticity is formulated along the lines proposed by Fleck andWillis (2009) for isotropic plasticity. Size-effects are included in the model due to the addition of gradient terms in both the free energy as well as through a dissipation potential. A finite...... element solution method is presented, which delivers the slip-rate field and the velocity-field based on two minimum principles. Some plane deformation problems relevant for certain specific orientations of a face centered cubic crystal under plane loading conditions are studied, and effective in......-plane parameters are developed based on the crystallographic properties of the material. The problem of cyclic shear of a single crystal between rigid platens is studied as well as void growth of a cylindrical void....

  15. Crystal formation in furunculosis agar

    Science.gov (United States)

    Bullock, G.L.; Ross, A.J.

    1964-01-01

    SINCE ITS INTRODUCTION SOME MONTHS AGO, FURUNCULOSIS AGAR has been employed in the diagnosis of suspect furunculosis and also as a general purpose medium. During our work with this medium we have noticed discrete "colonies," of crystalline material, which very closely resemble microbial colonies. These crystal colonies are compact and appear on both the surface and subsurface; they occur in inoculated slants and plates incubated for long periods (2 to 3 weeks), as well as in uninoculated stored medium. As the crystal colonies could be confusing to workers using this medium, we decided to attempt to identify them and also to determine whether storage conditions and different lots of medium affect crystal formation.

  16. Between Stage and Screen

    NARCIS (Netherlands)

    Tornqvist, Egil

    1996-01-01

    Ingmar Bergman is worldwide known as a film and stage director. Yet no-one has attempted to compare his stage and screen activities. In Between stage and screen Egil Tornqvist examines formal and thematical correspondences and differences between a number of Bergman's stage, screen, and radio produc

  17. Screen time and children

    Science.gov (United States)

    ... obesity ) Screen time increases your child's risk of obesity because: Sitting and watching a screen is time that is not spent being physically active. TV commercials and other screen ads can lead to unhealthy food choices . Most of the time, the foods in ads ...

  18. Screen Practice in Curating

    DEFF Research Database (Denmark)

    Toft, Tanya Søndergaard

    2014-01-01

    During the past one and a half decade, a curatorial orientation towards "screen practice" has expanded the moving image and digital art into the public domain, exploring alternative artistic uses of the screen. The emergence of urban LED screens in the late 1990s provided a new venue that allowed...

  19. Principles of Cancer Screening.

    Science.gov (United States)

    Pinsky, Paul F

    2015-10-01

    Cancer screening has long been an important component of the struggle to reduce the burden of morbidity and mortality from cancer. Notwithstanding this history, many aspects of cancer screening remain poorly understood. This article presents a summary of basic principles of cancer screening that are relevant for researchers, clinicians, and public health officials alike. Published by Elsevier Inc.

  20. Breast awareness and screening.

    Science.gov (United States)

    Harmer, Victoria

    Breast cancer is the most commonly diagnosed cancer in the UK. Breast awareness and screening, along with better treatment, can significantly improve outcomes, and more women than ever are now surviving the disease. This article discusses breast awareness and screening, symptoms and risk factors for breast cancer, and how nurses can raise breast awareness and screening uptake.