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Sample records for mm borax ph

  1. Desulphurization of coal using borax

    SciTech Connect

    Yaman, S.; Kuecuekbayrak, S.

    1996-12-31

    In this study, a high sulphur Turkish lignite was mixed with various amounts of solid borax [Na{sub 2}B{sub 4}O{sub 7}10H{sub 2}O] and then these mixtures were subjected to various oxydesulphurization processes. Effects of amount of borax, temperature and partial pressure of oxygen on sulphur removal and coal recovery were investigated in the ranges of 0.625--15.000 g for 5 g lignite, 423--498 K, 0.0--1.5 MPa, respectively.

  2. Dry borax applicator operator's manual.

    SciTech Connect

    Karsky, Richard, J.

    1999-01-01

    Annosum root rot affects conifers throughout the Northern Hemisphere, infecting their roots and eventually killing the trees. The fungus Heterobasidion annosum causes annosum root rot. The fungus colonizes readily on freshly cut stumps. Partially cut stands have a high risk of infestation because the fungus can colonize on each of the stumps and potentially infect the neighboring trees. Wind and rain carry the annosum spores. Spores that land on freshly cut stumps grow down the stump's root system where they can infect living trees through root grafts or root contacts. Once annosum becomes established, it can remain active for many years in the Southern United States and for several decades in the north. About 7% of the trees that become infected die. When thinning, stumps can be treated successfully using a competing fungus, Phlebia gigantea, and with ''Tim-Bor'' in liquid formulations. These liquid products are no longer approved in the United States. Only the dry powder form is registered and approved by the EPA. Stumps can be treated with a dry formula of borax, (Sporax), significantly reducing one of the primary routes by which Heterobasidion annosum infects a stand of trees. Sporax is used by the USDA Forest Service to control annosum root rot. Sporax is now applied by hand, but once the felled trees are skidded it becomes very hard to locate the stumps. A stump applicator will reduce error, labor costs, and hazards to workers.

  3. Assessment of boric acid and borax using the IEHR evaluative process for assessing human developmental and reproductive toxicity of agents

    SciTech Connect

    Moore, J.A.

    1995-03-01

    This document presents an evaluation of the reproductive and developmental effects of boric acid, H3BO3 (CAS Registry No. 10043-35-3) and disodium tetraborate decahydrate or borax, Na2B4O2O(CAS Registry No. 1303-96-4). The element, boron, does not exist naturally. In dilute aqueous solution and at physiological pH (7.4), the predominant species in undissociated boric acid (greater than 98%), irrespective of whether the initial material was boric acid of borax. Therefore, it is both useful and correct to compare exposures and dosages to boric acid and borax in terms of `boron equivalents`, since both materials form equivalent species in dilute aqueous solution with similar systemic effects. In order to be clear in this document, the term `boron` will refer to `boron equivalents` or percent boron in boric acid and borax.

  4. Crystallization kinetics of the borax decahydrate

    NASA Astrophysics Data System (ADS)

    Ceyhan, A. A.; Sahin, Ö.; Bulutcu, A. N.

    2007-03-01

    The growth and dissolution rates of borax decahydrate have been measured as a function of supersaturation for various particle sizes at different temperature ranges of 13 and 50 °C in a laboratory-scale fluidized bed crystallizer. The values of mass transfer coefficient, K, reaction rate constant, kr and reaction rate order, r were determined. The relative importances of diffusion and integration resistance were described by new terms named integration and diffusion concentration fraction. It was found that the overall growth rate of borax decahydrate is mainly controlled by integration (reaction) steps. It was also estimated that the dissolution region of borax decahydrate, apart from other materials, is controlled by diffusion and surface reaction. Increasing the temperature and particle size cause an increase in the values of kinetic parameters ( Kg, kr and K). The activation energies of overall, reaction and mass transfer steps were determined as 18.07, 18.79 and 8.26 kJmol -1, respectively.

  5. 40 CFR 415.270 - Applicability; description of the borax production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... borax production subcategory. 415.270 Section 415.270 Protection of Environment ENVIRONMENTAL PROTECTION... CATEGORY Borax Production Subcategory § 415.270 Applicability; description of the borax production... borax by the ore-mining process and by the Trona process....

  6. 40 CFR 436.130 - Applicability; description of the borax subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... borax subcategory. 436.130 Section 436.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Borax Subcategory § 436.130 Applicability; description of the borax subcategory. The provisions of this subpart are applicable to the processing of borate minerals. Borax obtained from brine lakes is...

  7. 40 CFR 436.130 - Applicability; description of the borax subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... borax subcategory. 436.130 Section 436.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Borax Subcategory § 436.130 Applicability; description of the borax subcategory. The provisions of this subpart are applicable to the processing of borate minerals. Borax obtained from brine lakes is...

  8. 40 CFR 436.130 - Applicability; description of the borax subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... borax subcategory. 436.130 Section 436.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Borax Subcategory § 436.130 Applicability; description of the borax subcategory. The provisions of this subpart are applicable to the processing of borate minerals. Borax obtained from brine lakes is...

  9. [Control of the Pharaoh's ant with borax bait formulations].

    PubMed

    Klunker, R; Scheurer, S; Neumann, T

    1990-12-01

    Results are given for the experimental control of Pharaoh ants, Monomorium pharaonis L., with persistent borax baits in the laboratory and the field. DYBH-bait formulations with about 17 per cent borax are very attractive and have a good effectivity. In 5 different objects infested with this ant eradication was proved to be possible with this experimental formulations. The progress of eradication depends essentially on the good organisational preparation of control measures. PMID:2095049

  10. Intracrystalline site preference of hydrogen isotopes in borax

    SciTech Connect

    Pradhananga, T.M.; Matsuo, S.

    1985-01-03

    The total hydrogen involved in borax synthesized at 25/sup 0/C in aqueous solution is enriched in deuterium by 5.3% compared with the mother liquor. There is no change in the value of the D/H fractionation factor between the hydrogen in borax and those in the mother liquor with changes in the degree of supersaturation. The fractionation factor changes slightly with a change in the crystallization temperature of borax in the range from 5 to 25/sup 0/C. The D/H ratio in the different sites of borax was estimated by a fractional dehydration technique. The results show that hydrogen atoms of the polyanionic group (B/sub 4/O/sub 5/(OH)/sub 4/) are much more enriched in deuterium than those of the cationic group (Na/sub 2/ x 8H/sub 2/O). The delta D values, referred to the mother liquor from which the borax was crystallized, for the cationic group (site A) and the polyanionic group (site B) are -35 +/- 3 and 167 +/- 13%, respectively based on the fractional dehydration results obtained at -21/sup 0/C. At -21/sup 0/C, isotopic exchange between different sites during dehydration is assumed not to occur. The mechanism for dehydration of borax is discussed. 48 references, 8 figures, 3 tables.

  11. Borax spends $30M for cogeneration system. [US Borax and Chemical Corp

    SciTech Connect

    Barber, J.

    1982-09-20

    A $30 million natural-gas-fired turbine power plant will provide all the electricity and steam needed at the US Borax and Chemical Corp. plant in Los Angeles. The cogeneration facility will come on line in 1984, and will pay for itself in about five years. The plant will use only half the 46 megawatts produced, the 22 megawatt surplus being sold to Southern California Edison Co. on a 20-year contract at a price pegged to the utility's avoided costs. Natural gas consumption at the plant will remain about the same. (DCK)

  12. 40 CFR 436.130 - Applicability; description of the borax subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... borax subcategory. 436.130 Section 436.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS MINERAL MINING AND PROCESSING POINT SOURCE CATEGORY Borax Subcategory § 436.130 Applicability; description of the borax subcategory. The provisions of this subpart...

  13. 40 CFR 415.270 - Applicability; description of the borax production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the borax... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Borax Production Subcategory § 415.270 Applicability; description of the borax production subcategory....

  14. 40 CFR 415.270 - Applicability; description of the borax production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the borax... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Borax Production Subcategory § 415.270 Applicability; description of the borax production subcategory....

  15. 40 CFR 415.270 - Applicability; description of the borax production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the borax... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Borax Production Subcategory § 415.270 Applicability; description of the borax production subcategory....

  16. 40 CFR 415.270 - Applicability; description of the borax production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Applicability; description of the borax... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Borax Production Subcategory § 415.270 Applicability; description of the borax production subcategory....

  17. Borax-Loaded PLLA for Promotion of Myogenic Differentiation.

    PubMed

    Rico, Patricia; Rodrigo-Navarro, Aleixandre; Salmerón-Sánchez, Manuel

    2015-11-01

    Boron is an essential metalloid, which plays a key role in plant and animal metabolisms. It has been reported that boron is involved in bone mineralization, has some uses in synthetic chemistry, and its potential has been only recently exploited in medicinal chemistry. However, in the area of tissue engineering, the use of boron is limited to works involving certain bioactive glasses. In this study, we engineer poly(l-lactic acid) (PLLA) substrates with sustained release of boron. Then, we analyze for the first time the uniqueness effects of boron in cell differentiation using murine C2C12 myoblasts and discuss a potential mechanism of action in cooperation with Ca(2+). Our results demonstrate that borax-loaded materials strongly enhance myotube formation at initial steps of myogenesis. Furthermore, we demonstrate that Ca(2+) plays an essential role in combination with borax as chelating or blocking Ca(2+) entry into the cell leads to a detrimental effect on myoblast differentiation observed on borax-loaded materials. This research identifies borax-loaded materials to trigger differentiation mechanisms and it establishes a new tool to engineer microenvironments with applications in regenerative medicine for muscular diseases. PMID:26239605

  18. Photonic crystal borax competitive binding carbohydrate sensing motif†

    PubMed Central

    Cui, Qingzhou; Muscatello, Michelle M. Ward; Asher, Sanford A.

    2009-01-01

    We developed a photonic crystal sensing method for diol containing species such as carbohydrates based on a poly(vinyl alcohol) (PVA) hydrogel containing an embedded crystalline colloidal array (CCA). The polymerized CCA (PCCA) diffracts visible light. We show that in the presence of borax the diffraction wavelength shifts as the concentration of glucose changes. The diffraction shifts result from the competitive binding of glucose to borate, which reduces the concentration of borate bound to the PVA diols. PMID:19381378

  19. Effect of borax on the crystallization kinetics of boric acid

    NASA Astrophysics Data System (ADS)

    Şahin, Ömer

    2002-03-01

    The effect of different borax concentrations on the growth and dissolution rates of boric acid crystals were measured in a fluidized bed crystallizer under well-established conditions of supersaturation and undersaturation and fluidization. It was found that the presence of borax in boric-acid solution decreases the mass-transfer coefficient, kd, the surface-reaction constant, kr and reaction order r pertaining to growth and dissolution rates of boric acid crystals. The effectiveness factors were estimated from the growth rate data to evaluate the relative magnitudes of the two resistances in series, diffusion and integration. The controlling mechanism is mainly by integration for the crystal growth of boric acid in the pure state and in the presence of borax in solution. The kinetic parameters ( kr, kd, r) were determined by a new method which is called trial and error under no assumption. This method gives a high accuracy of determination of the mass-transfer coefficient, kd, the surface-reaction constant, kr and surface-reaction order, r. The relative standard deviation between the equation Rg= kr(( ρα- ρeq)- Rg(1- wα)/ kd) r and those experimentally obtained and represented by the equation Rg= kg( ρα- ρeq) g do not exceed 0.013 for both the growth and dissolution regions.

  20. Toxicity detection of sodium nitrite, borax and aluminum potassium sulfate using electrochemical method.

    PubMed

    Yu, Dengbin; Yong, Daming; Dong, Shaojun

    2013-04-01

    Based on the inhibition effect on the respiratory chain activity of microorganisms by toxicants, an electrochemical method has been developed to measure the current variation of a mediator in the presence of microorganisms contacted with a toxicant. Microelectrode arrays were adopted in this study, which can accelerate the mass transfer rate of an analyte to the electrode and also increase the total current signal, resulting in an improvement in detection sensitivity. We selected Escherichia coli as the testee and the standard glucose-glutamic acid as an exogenous material. Under oxygen restriction, the experiments in the presence of toxicant were performed at optimum conditions (solution pH 7.0, 37 degrees C and reaction for 3 hr). The resulting solution was then separated from the suspended microorganisms and was measured by an electrochemical method, using ferricyanide as a mediator. The current signal obtained represents the reoxidation of ferrocyanide, which was transformed to inhibiting efficiency, IC50, as a quantitative measure of toxicity. The IC50 values measured were 410, 570 and 830 mg/L for sodium nitrite, borax and aluminum potassium sulfate, respectively. The results show that the toxicity sequence for these three food additives is consistent with the value reported by other methods. Furthermore, the order of damage degree to the microorganism was also observed to be: sodium nitrite > borax > aluminum potassium sulfate > blank, according to the atomic force microscopy images of E. coli after being incubated for 3 hr with the toxic compound in buffer solutions. The electrochemical method is expected to be a sensitive and simple alternative to toxicity screening for chemical food additives. PMID:23923788

  1. In vivo measurements of sulcal plaque pH in rats after topical applications of xylitol, sorbitol, glucose, sucrose, and sucrose plus 53 mM sodium fluoride.

    PubMed

    Firestone, A R; Navia, J M

    1986-01-01

    In two series of experiments, Sprague-Dawley-derived rats were infected orally with cariogenic micro-organisms and fed caries-promoting diets. By means of an antimony electrode, resting pH values were measured in the mesial sulcus of the maxillary left first molar. 100 or 200 microL of the test solutions were applied, and the change in pH (delta pH) was recorded for three min. Test solutions were: (a) 10% sucrose, 10% glucose, 10% sorbitol, or 10% xylitol; (b) 0%, 10%, 20%, or 40% sucrose; (c) 0%, 3%, 7%, or 10% sucrose; and (d) 10% sucrose, 10% sucrose + 53 mmol/L NaF (1000 ppmF-), or 10% sucrose + 53 mmol/L NaCl. Experimental design was a 4 X 4 Latin square (a, b, c) or a cross-over design (d). Solutions of sucrose and glucose gave significantly greater decreases in pH than did sorbitol or xylitol. pH fall was maximal for 10% sucrose and significantly less for 40% sucrose during the three-minute experimental period. For sucrose solutions ranging in concentration from 3 to 10%, pH fall was highest after application of 10% sucrose when plaque was previously rinsed with water, but this pH fall did not differ significantly from that obtained using a 7% sucrose solution. Adding 1000 ppmF- to a 10% sucrose solution caused an increase in pH. Rinsing the teeth to remove saliva resulted in significantly lower resting pH values. The results of these experiments are in agreement with the results of human plaque pH measurements. PMID:3455697

  2. Decontamination and decommissioning of the BORAX-V leach pond. Final report

    SciTech Connect

    Smith, D.L.

    1985-01-01

    This report describes the decontamination and decommissioning (D and D) of the BORAX-V leach pond located at the Idaho National Engineering Laboratory (INEL). The leach pond became radioactively contaminated from the periodic discharge of low-level liquid waste during operation of the Boiling Water Reactor Experiments (BORAX) from 1954 to 1964. This report describes work performed to accomplish the D and D objectives of stabilizing the leach pond and preventing the spread of contamination. D and D of the BORAX-V leach pond consisted to backfilling the pond with clean soil, grading and seeding the area, and erecting a permanent marker to identify very low-level subsurface contamination.

  3. Hydrologic data and description of a hydrologic monitoring plan for the Borax Lake area, Oregon

    USGS Publications Warehouse

    Schneider, Tiffany Rae; McFarland, William D.

    1995-01-01

    Information from field visits was used to develop a monitoring plan. The plan would include monitoring Borax Lake by measuring discharge, stage, evaporation, temperature, and specific conductance; water-quality sampling and analysis; and monitoring shallow ground-water levels near Borax Lake using shallow piezometers. Minimally, one hot spring in North Borax Lake Spring Group 1 would be monitored for temperature and specific conductance and sampled for water-quality analysis. In addition, two flowing wells would be monitored for water levels, temperature, specific conductance, and discharge and sampled for water-quality analysis. The construction characteristics of these wells must be verified before long-term data collection begins. In the future, it may be helpful to monitor shallow and (or) deep observation wells drilled into the thermal aquifer to understand the possible effects of geothermal development on Borax Lake and nearby springs.

  4. Effect of Cetyltrimethylammonium Bromide (CTAB) on the Growth Rate and Morphology of Borax Crystals

    NASA Astrophysics Data System (ADS)

    Suharso; Parkinson, Gordon; Ogden, Mark

    An investigation of the effect of cetyltrimethylammonium bromide (CTAB) on both growth rate and morphology of borax crystal has been carried out. This experiment was carried out at temperature of 25°C and relative supersaturation of 0.21 and 0.74 under in situ cell optical microscopy method. The result shows that CTAB inhibits the growth rate and changes the morphology of borax crystal.

  5. Geophysical Characterization of the Borax Lake Hydrothermal System in the Alvord Desert, Southeastern Oregon.

    NASA Astrophysics Data System (ADS)

    Hess, S.; Paul, C.; Bradford, J.; Lyle, M.; Clement, W.; Liberty, L.; Myers, R.; Donaldson, P.

    2003-12-01

    We are conducting a detailed geophysical characterization of an active hydrothermal system as part of an interdisciplinary project aiming to study the link between the physical characteristics of hydrothermal systems and biota that occupy those systems. The Borax Lake Hydrothermal System (BLHS), consisting of Borax Lake and the surrounding hot springs, is located near the center of the Alvord Basin in southeastern Oregon. As a result of Basin and Range extension, the Alvord Basin is a north-south trending graben bounded by the Steens Mountains to the west and the Trout Creek Mountains to the east. We are using several geophysical techniques to generate both basin-wide and high-resolution local characterizations of the Alvord Basin and the BLHS. To date we have completed two scales of seismic reflection surveys: an east-west trending basin scale survey and a shallow (~10 - 300 m depth) 3D survey of the BLHS. The basin scale seismic survey consists of 11 km of 2D, 60 fold CMP data acquired with a 200 lb accelerated weight drop. We acquired the 3D survey of the BLHS using a 7.62x39 mm SKS rifle and 240 channel recording system. The 3D patch covers ~ 90,000 sq. m with a maximum inline offset aperture of 225 m, crossline aperture of 75 m, and 360 degree azimuthal coverage. Additionally, we have completed a regional total-field magnetic survey for a large portion of the Alvord Basin and a 3D transient electromagnetic (TEM) survey of the BLHS. The 3D TEM survey covers the central portion of the 3D seismic survey. Initial results from the regional magnetic and seismic surveys indicate a mid-basin basement high. The basement high appears to correlate with the northeast trending BLHS. Additionally, the cross-basin seismic profile clearly shows that recent deformation has primarily been along an eastward dipping normal fault that bounds the basement high to the east. This suggests that both spatial and temporal characteristics of deformation control hydrothermal activity

  6. Measurement and analysis of polar stratospheric ClO and N2O by ground-based mm-wave spectroscopy. Ph.D. Thesis

    SciTech Connect

    Emmons, L.K.

    1994-01-01

    Analysis and interpretation of measured spectra of spring-time stratospheric ClO and N2O in Antarctica and Greenland during three field campaigns are presented in this dissertation. Measurements were made at McMurdo Station, Antarctica during September and October in 1992, and at Thule Air Base, Greenland during February and March in 1992 and 1993, using a ground-based mm-wave receiver. Measurements of ClO, a direct product of ozone destruction, were made through the evolution of the Antarctic `ozone hole.` The emission spectrum of ClO at 278.632 GHz was observed and vertical profiles have been determined from measurements both inside and outside the polar vortex and a sharp difference is seen between them. Comparisons are made to coincident balloon and satellite measurements of ozone, and ground-based measurements of NO2. The Arctic polar vortex generally has warmer stratospheric temperatures and is more variable in its position over the pole, consequently no ozone hole has been observed there. However, these measurements, as well as others, show the presence of ClO indicating some ozone depletion has occurred by the same mechanisms at work in the Antarctic. Low altitude mixing ratios of ClO in 1992 were never above 0.2 ppbv, but in 1993 up to 0.5 ppbv was observed in late February. The diurnal variation of the low altitude layer of ClO present in the Antarctic ozone `hole` has also been measured. The mixing ratio increases after sunrise, from less than 0.1 ppbv just before sunrise to approximately 1.5 ppbv at midday, and decreases with increasing solar zenith angle after midday. This diurnal record is unique and is valuable for the validation of photochemical models of the polar stratosphere. N2O is a good tracer of stratospheric dynamics, having only ground sources and having a long chemical lifetime in the atmosphere. N2O spectra at 276.328 GHz were observed at Thule from late February to late March, 1992.

  7. Borax counteracts genotoxicity of aluminum in rat liver.

    PubMed

    Turkez, Hasan; Geyikoğlu, Fatime; Tatar, Abdulgani

    2013-10-01

    This study was carried out to evaluate the protective role of borax (BX) on genotoxicity induced by aluminum (Al) in rat liver, using liver micronucleus assay as an indicator of genotoxicity. Sprague-Dawley rats were randomly separated into six groups and each group had four animals. Aluminum chloride (AlCl₃; 5 mg/kg b.w.) and BX (3.25 and 13 mg/kg b.w.) were injected intraperitoneally to rats. Besides, animals were also treated with Al for 4 consecutive days followed by BX for 10 days. Rats were anesthetized after Al and BX injections and the hepatocytes were isolated for counting the number of micronucleated hepatocytes (MNHEPs). AlCl₃ was found to significantly (p < 0.05) increase the number of MNHEPs. Rats treated with BX, however, showed no increase in MNHEPs. Moreover, simultaneous treatments with BX significantly modulated the genotoxic effects of AlCl₃ in rats. It can be concluded that BX has beneficial influences and has the ability to antagonize Al toxicity. PMID:22491726

  8. Experimental determination of the metastable zone width of borax decahydrate by ultrasonic velocity measurement

    NASA Astrophysics Data System (ADS)

    Gürbüz, H.; Özdemir, B.

    2003-05-01

    The metastable zone width of borax decahydrate (disodium tetraborate decahydrate), represented by the maximum undercooling Δ Tmax, both in pure and impure aqueous solutions were determined according to polythermal method by using the ultrasonic technique. It is found that the metastable zone width of borax decahydrate in pure solutions determined by ultrasonic method fulfills well the linear relation between logΔ Tmax and log(-d T/d t). However, the sensitivity of the method using the ultrasonic technique increases with increasing saturation temperature, probably due to the increase of temperature dependence of solubility with increasing saturation temperature. A comparison of the nucleation temperatures from ultrasonic measurements and from visual determination shows that both detection techniques give almost the same results for borax decahydrate. The results obtained from ultrasonic measurements show, that the presence of Ca 2+ as impurity has only a small effect on the metastable zone width of borax decahydrate as long as the impurity concentrations is in the range of 25-200 ppm. Similar to the effect of Ca 2+, Mg 2+ also has a small effect on the metastable zone width of borax up to the impurity concentration of 100 ppm. However, the presence of 200 ppm Mg 2+ results in a reasonable increase of the metastable zone width.

  9. Response to Thermal Exposure of Ball-Milled Aluminum-Borax Powder Blends

    NASA Astrophysics Data System (ADS)

    Birol, Yucel

    2013-04-01

    Aluminum-borax powder mixtures were ball milled and heated above 873 K (600 °C) to produce Al-B master alloys. Ball-milled powder blends reveal interpenetrating layers of deformed aluminum and borax grains that are increasingly refined with increasing milling time. Thermal exposure of the ball-milled powder blends facilitates a series of thermite reactions between these layers. Borax, dehydrated during heating, is reduced by Al, and B thus generated reacts with excess Al to produce AlB2 particles dispersed across the aluminum grains starting at 873 K (600 °C). AlB2 particles start to form along the interface of the aluminum and borax layers. Once nucleated, these particles grow readily to become hexagonal-shaped crystals that traverse the aluminum grains with increasing temperatures as evidenced by the increase in the size as well as in the number of the AlB2 particles. Ball milling for 1 hour suffices to achieve a thermite reaction between borax and aluminum. Ball milling further does not impact the response of the powder blend to thermal exposure. The nucleation-reaction sites are multiplied, however, with increasing milling time and thus insure a higher number of smaller AlB2 particles. The size of the AlB2 platelets may be adjusted with the ball milling time.

  10. Prediction of Layer Thickness in Molten Borax Bath with Genetic Evolutionary Programming

    NASA Astrophysics Data System (ADS)

    Taylan, Fatih

    2011-04-01

    In this study, the vanadium carbide coating in molten borax bath process is modeled by evolutionary genetic programming (GEP) with bath composition (borax percentage, ferro vanadium (Fe-V) percentage, boric acid percentage), bath temperature, immersion time, and layer thickness data. Five inputs and one output data exist in the model. The percentage of borax, Fe-V, and boric acid, temperature, and immersion time parameters are used as input data and the layer thickness value is used as output data. For selected bath components, immersion time, and temperature variables, the layer thicknesses are derived from the mathematical expression. The results of the mathematical expressions are compared to that of experimental data; it is determined that the derived mathematical expression has an accuracy of 89%.

  11. Effect of borax concentration on the structure of Poly(Vinyl Alcohol) gels

    NASA Astrophysics Data System (ADS)

    Lawrence, Mathias B.; Desa, J. A. E.; Aswal, V. K.

    2012-06-01

    Poly(Vinyl Alcohol) hydrogels cross-linked with varying concentrations of borax have been studied using Small-Angle Neutron Scattering and X-Ray Diffraction. The intensity of scattering increases with borax concentration from 1 mg/ml up to 2 mg/ml and falls thereafter for 4 mg/ml, increasing again for a concentration of 10 mg/ml. The mesoscopic structural changes that cause these trends in the SANS data are in keeping with the variations in the X-ray diffraction patterns pertaining to structures within the PVA chains.

  12. Enhancing fluorescence intensity of Ellagic acid in Borax-HCl-CTAB micelles

    NASA Astrophysics Data System (ADS)

    Wang, Feng; Huang, Wei; Zhang, Shuai; Liu, Guokui; Li, Kexiang; Tang, Bo

    2011-03-01

    Ellagic acid (C 14H 6O 8), a naturally occurring phytochemical, found mainly in berries and some nuts, has anticarcinogenic and antioxidant properties. It is found that fluorescence of Ellagic acid (EA) is greatly enhanced by micelle of cetyltrimethylammonium bromide (CTAB) surfactant. Based on this effect, a sensitive proposed fluorimetric method was applied for the determination of Ellagic acid in aqueous solution. In the Borax-HCl buffer, the fluorescence intensity of Ellagic acid in the presence of CTAB is proportional to the concentration of Ellagic acid in range from 8.0 × 10 -10 to 4.0 × 10 -5 mol L -1; and the detection limits are 3.2 × 10 -10 mol L -1 and 5.9 × 10 -10 mol L -1 excited at 266 nm and 388 nm, respectively. The actual samples of pomegranate rinds are simply manipulated and satisfactorily determined. The interaction mechanism studies argue that the negative EA-Borax complex is formed and solubilized in the cationic surfactant CTAB micelle in this system. The fluorescence intensity of EA enhances because the CTAB micelle provides a hydrophobic microenvironment for EA-Borax complex, which can prevent collision with water molecules and decrease the energy loss of EA-Borax complex.

  13. Dispersion of borax in plastic is excellent fire-retardant heat insulator

    NASA Technical Reports Server (NTRS)

    Evans, H.; Hughes, J.; Schmitz, F.

    1967-01-01

    A mix of borax powder and a chlorinated anhydrous polyester resin yields a plastic composition that is fire-retardant, yields a minimum of toxic gases when heated, and exhibits high thermal insulating properties. This composition can be used as a coating or can be converted into laminated or cast shapes.

  14. 40 CFR 436.130 - Applicability; description of the borax subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the borax subcategory. 436.130 Section 436.130 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS MINERAL MINING AND PROCESSING POINT SOURCE CATEGORY...

  15. Borax as flux on sintering of iron Ancor Steel 1000® under glow discharge

    NASA Astrophysics Data System (ADS)

    Ariza Suarez, H. G.; Sarmiento Santos, A.; Ortiz Otálora, C. A.

    2016-02-01

    This work studies the flux effect of borax (di sodium tetraborate decahydrate) on sintering of iron Ancor Steel 1000® in abnormal glow discharge. The incidence of the percentage by weight of borax and the sintering temperature in the process were observed. Samples of powder metallurgical iron were prepared with proportions of 0.50%, 2.0%, 4.0% and 6.0% by weight of borax using the procedures of powder metallurgy. The samples were sintered at 800 and 1100°C for 30min, by glow discharge at low pressure in a reducing atmosphere composed of 20% H2+80% Ar. The samples in compact green-state were analyzed by TGA-DSC to determine the fusion process and mass loss during sintering. The analysis of microhardness and density, shows that at a sintering temperature of 800°C the sample density decreases and the sample microhardness increases with respect to sintered samples without borax. Sintered samples were analysed by DRX showing the absence of precipitates.

  16. Borax-induced apoptosis in HepG2 cells involves p53, Bcl-2, and Bax.

    PubMed

    Wei, Y; Yuan, F J; Zhou, W B; Wu, L; Chen, L; Wang, J J; Zhang, Y S

    2016-01-01

    Borax, a boron compound and a salt of boric acid, is known to inhibit the growth of tumor cells. HepG2 cells have been shown to be clearly susceptible to the anti-proliferative effects of borax. However, the specific mechanisms regulating this effect are poorly understood. This study aimed to investigate the pathways underlying the growth inhibition induced by borax in HepG2 cells. The effects of borax on HepG2 cell viability were characterized using MTT. Apoptosis was also verified by annexin V/propidium iodide staining. JC-1 dye and western blotting techniques were used to measure mitochondrial membrane potential and p53, Bax, and Bcl-2 protein expression, respectively. Relevant mRNA levels were measured by qRT-PCR. Borax inhibited the proliferation of HepG2 cells in a time- and dose-dependent manner in vitro. The apoptotic process triggered by borax involved the upregulation of p53 and Bax and the downregulation of Bcl-2, which was confirmed by a change in the mitochondrial membrane potential. These results elucidate a borax-induced apoptotic pathway in HepG2 cells that involves the upregulation of p53 and Bax and the downregulation of Bcl-2. PMID:27420953

  17. Characterization of uranium surfaces machined with aqueous propylene glycol-borax or perchloroethylene-mineral oil coolants

    SciTech Connect

    Cristy, S.S.; Bennett, R.K. Jr.; Dillon, J.J.; Richards, H.L.; Seals, R.D.; Byrd, V.R.

    1986-12-31

    The use of perchloroethylene (perc) as an ingredient in coolants for machining enriched uranium at the Oak Ridge Y-12 Plant has been discontinued because of environmental concerns. A new coolant was substituted in December 1985, which consists of an aqueous solution of propylene glycol with borax (sodium tetraborate) added as a nuclear poison and with a nitrite added as a corrosion inhibitor. Uranium surfaces machined using the two coolants were compared with respects to residual contamination, corrosion or corrosion potential, and with the aqueous propylene glycol-borax coolant was found to be better than that of enriched uranium machined with the perc-mineral oil coolant. The boron residues on the final-finished parts machined with the borax-containing coolant were not sufficient to cause problems in further processing. All evidence indicated that the enriched uranium surfaces machined with the borax-containing coolant will be as satisfactory as those machined with the perc coolant.

  18. Determination of kinetic parameters of crystal growth rate of borax in aqueous solution by using the rotating disc technique

    NASA Astrophysics Data System (ADS)

    Sahin, Omer; Aslan, Fevzi; Ozdemir, Mustafa; Durgun, Mustafa

    2004-10-01

    Growth rate of polycrystalline disc of borax compressed at different pressure and rotated at various speed has been measured in a rotating disc crystallizer under well-defined conditions of supersaturation. It was found that the mass transfer coefficient, K, increased while overall growth rate constant, Kg, and surface reaction constant, kr, decreased with increasing smoothness of the disc. It was also determined that kinetic parameters (kr , r , K , g) of crystal growth rate of borax decreased with increasing rotating speed of the polycrystalline disc. The effectiveness factor was calculated from the growth rate data to evaluate the relative magnitude of the steps in series bulk diffusion through the mass transfer boundary layer and the surface integration. At low rotating speed of disc, the crystal growth rate of borax is mainly controlled by integration. However, both diffusion and integration steps affect the growth rate of borax at higher rotating speed of polycrystalline disc.

  19. Corrosion resistance of inconel 690 to borax, boric acid, and boron nitride at 1100{degrees}C

    SciTech Connect

    Imrich, K.J.

    1996-12-12

    Significant general and localized corrosion was observed on Inconel 690 coupons following exposure to borax, boric acid and boron nitride at 1100{degrees}C. Severe localized attack at and below the melt line was observed on coupons exposed to borax. An intergranular attack at and below the melt line was observed on coupons exposed to borax. An intergranular attack (IGA) of the Inconel 690 was also observed. Severe internal void formation and IGA (30 mils penetration after 3 days) was observed in the coupon exposed to boric acid. Both borax and boric acid remove the protective chromium oxide; however, this layer can be reestablished by heating the Inconel 690 to 975 {degrees}C in air for several hours. Inconel 690 in direct contact with boron nitride resulted in the formation of a thick chromium borate layer, a general corrosion rate of 50 to 90 mils per year, and internal void formation of 1 mil per day.

  20. Final report of the decontamination and decommissioning of the BORAX-V facility turbine building

    SciTech Connect

    Arave, A.E.; Rodman, G.R.

    1992-12-01

    The Boiling Water Reactor Experiment (BORAX)-V Facility Turbine Building Decontamination and Decommissioning (D&D) Project is described in this report. The BORAX series of five National Reactor Testing Station (NRTS) reactors pioneered intensive work on boiling water reactor (BWR) experiments conducted between 1953 and 1964. Facility characterization, decision analyses, and D&D plans for the turbine building were prepared from 1979 through 1990. D&D activities of the turbine building systems were initiated in November of 1988 and completed with the demolition and backfill of the concrete foundation in March 1992. Due to the low levels of radioactivity and the absence of loose contamination, the D&D activities were completed with no radiation exposure to the workers. The D&D activities were performed in a manner that no radiological health or safety hazard to the public or to personnel at the Idaho National Engineering Laboratory (INEL) remain.

  1. Validation of MCNP: SPERT-D and BORAX-V fuel

    SciTech Connect

    Crawford, C.; Palmer, B.

    1992-11-01

    This report discusses critical experiments involving SPERT-D[sup 1,2] fuel elements and BORAX-V[sup 3-8] fuel which have been modeled and calculations performed with MCNP. MCNP is a Monte Carlo based transport code. For this study continuous-energy nuclear data from the ENDF/B-V cross section library was used. The SPERT-D experiments consisted of various arrays of fuel elements moderated and reflected with either water or a uranyl nitrate solution. Some SPERT-D experiments used cadmium as a fixed neutron poison, while others were poisoned with various concentrations of boron in the moderating/reflecting solution. ne BORAX-V experiments were arrays of either boiling fuel rod assemblies or superheater assemblies, both types of arrays were moderated and reflected with water. In one boiling fuel experiment, two fuel rods were replaced with borated stainless steel poison rods.

  2. Final report of the decontamination and decommissioning of the BORAX-V facility turbine building

    SciTech Connect

    Arave, A.E.; Rodman, G.R.

    1992-12-01

    The Boiling Water Reactor Experiment (BORAX)-V Facility Turbine Building Decontamination and Decommissioning (D D) Project is described in this report. The BORAX series of five National Reactor Testing Station (NRTS) reactors pioneered intensive work on boiling water reactor (BWR) experiments conducted between 1953 and 1964. Facility characterization, decision analyses, and D D plans for the turbine building were prepared from 1979 through 1990. D D activities of the turbine building systems were initiated in November of 1988 and completed with the demolition and backfill of the concrete foundation in March 1992. Due to the low levels of radioactivity and the absence of loose contamination, the D D activities were completed with no radiation exposure to the workers. The D D activities were performed in a manner that no radiological health or safety hazard to the public or to personnel at the Idaho National Engineering Laboratory (INEL) remain.

  3. Validation of MCNP: SPERT-D and BORAX-V fuel

    SciTech Connect

    Crawford, C.; Palmer, B.

    1992-11-01

    This report discusses critical experiments involving SPERT-D{sup 1,2} fuel elements and BORAX-V{sup 3-8} fuel which have been modeled and calculations performed with MCNP. MCNP is a Monte Carlo based transport code. For this study continuous-energy nuclear data from the ENDF/B-V cross section library was used. The SPERT-D experiments consisted of various arrays of fuel elements moderated and reflected with either water or a uranyl nitrate solution. Some SPERT-D experiments used cadmium as a fixed neutron poison, while others were poisoned with various concentrations of boron in the moderating/reflecting solution. ne BORAX-V experiments were arrays of either boiling fuel rod assemblies or superheater assemblies, both types of arrays were moderated and reflected with water. In one boiling fuel experiment, two fuel rods were replaced with borated stainless steel poison rods.

  4. Genotoxic effects of boric acid and borax in zebrafish, Danio rerio using alkaline comet assay.

    PubMed

    Gülsoy, Nagihan; Yavas, Cüneyd; Mutlu, Özal

    2015-01-01

    The present study is conducted to determine the potential mechanisms of Boron compounds, boric acid (BA) and borax (BX), on genotoxicity of zebrafish Danio rerio for 24, 48, 72 and 96-hours acute exposure (level:1, 4, 16, 64 mg/l BA and BX) in semi-static bioassay experiment. For that purpose, peripheral erythrocytes were drawn from caudal vein and Comet assay was applied to assess genotoxicity. Acute (96 hours) exposure and high concentrations of boric acid and borax increases % tail DNA and Olive tail moment. Genotoxicity was found for BA as concentration-dependent and BX as concentration and time dependent manner. In general, significant effects (P < 0,05) on both concentrations and exposure times were observed in experimental groups. DNA damage was highest at 96 h and 24 h for all BX and BA concentrations, respectively in peripheral blood of D. rerio. For the first time, our study demonstrates the effect of waterborne BA and BX exposure on genotoxicity at the molecular level, which may contribute to understanding the mechanism of boric acid and borax-induced genotoxicity in fish. PMID:26862320

  5. Genotoxic effects of boric acid and borax in zebrafish, Danio rerio using alkaline comet assay

    PubMed Central

    Gülsoy, Nagihan; Yavas, Cüneyd; Mutlu, Özal

    2015-01-01

    The present study is conducted to determine the potential mechanisms of Boron compounds, boric acid (BA) and borax (BX), on genotoxicity of zebrafish Danio rerio for 24, 48, 72 and 96-hours acute exposure (level:1, 4, 16, 64 mg/l BA and BX) in semi-static bioassay experiment. For that purpose, peripheral erythrocytes were drawn from caudal vein and Comet assay was applied to assess genotoxicity. Acute (96 hours) exposure and high concentrations of boric acid and borax increases % tail DNA and Olive tail moment. Genotoxicity was found for BA as concentration-dependent and BX as concentration and time dependent manner. In general, significant effects (P < 0,05) on both concentrations and exposure times were observed in experimental groups. DNA damage was highest at 96 h and 24 h for all BX and BA concentrations, respectively in peripheral blood of D. rerio. For the first time, our study demonstrates the effect of waterborne BA and BX exposure on genotoxicity at the molecular level, which may contribute to understanding the mechanism of boric acid and borax-induced genotoxicity in fish. PMID:26862320

  6. 8mm/16mm Movie-Making.

    ERIC Educational Resources Information Center

    Provisor, Henry

    The materials, techniques, and attitudes needed to make professional-quality movies using 8mm., super 8mm., and 16mm. amateur equipment are covered in this guide to movie-making. The pros and cons are discussed of the various makes and models of cameras and lenses. Other topics discussed are: exposure and lighting, choosing film, camera speed and…

  7. a Theoretical Analysis of Physical Properties of Aqueous Trehalose with Borax

    NASA Astrophysics Data System (ADS)

    Sahara; Aniya, Masaru

    2013-07-01

    The temperature and composition dependence of the viscosity of aqueous trehalose and aqueous trehalose-borax mixtures has been investigated by means of the Bond Strength-Coordination Number Fluctuation (BSCNF) model. The result indicates that the variation in the fragility of the system is very small in the composition range analyzed. The values of the materials parameters determined are consistent with those of the trehalose-water-lithium iodide system which were analyzed in a previous study. Based on the analysis of the obtained parameters of the BSCNF model, the physical interpretation of the WLF parameters reported in a previous study is reconfirmed.

  8. Development of a cleaning process for uranium chips machined with a glycol-water-borax coolant

    SciTech Connect

    Taylor, P.A.

    1984-12-01

    A chip-cleaning process has been developed to remove the new glycol-water-borax coolant from oralloy chips. The process involves storing the freshly cut chips in Freon-TDF until they are cleaned, washing with water, and displacing the water with Freon-TDF. The wash water can be reused many times and still yield clean chips and then be added to the coolant to make up for evaporative losses. The Freon-TDF will be cycled by evaporation. The cleaning facility is currently being designed and should be operational by April 1985.

  9. Epoxy-borax-coal tar composition for a radiation protective, burn resistant drum liner and centrifugal casting method

    SciTech Connect

    Boyer, N.W.; Taylor, R.S.

    1980-10-28

    A boron containing burn resistant, low level radiation protection material useful, for example, as a liner for radioactive waste disposal and storage, a component for neutron absorber, and a shield for a neutron source. The material is basically composed of borax in the range of 25-50%, coal tar in the range of 25-37.5%, with the remainder being an epoxy resin mix. A preferred composition is 50% borax, 25% coal tar and 25% epoxy resin. The material is not susceptible to burning and is about 1/5 the cost of existing radiation protection material utilized in similar applications.

  10. Epoxy-borax-coal tar composition for a radiation protective, burn resistant drum liner and centrifugal casting method

    DOEpatents

    Taylor, Robert S.; Boyer, Norman W.

    1980-01-01

    A boron containing burn resistant, low level radiation protection material useful, for example, as a liner for radioactive waste disposal and storage, a component for neutron absorber, and a shield for a neutron source. The material is basically composed of Borax in the range of 25-50%, coal tar in the range of 25-37.5%, with the remainder being an epoxy resin mix. A preferred composition is 50% Borax, 25% coal tar and 25% epoxy resin. The material is not susceptible to burning and is about 1/5 the cost of existing radiation protection material utilized in similar applications.

  11. Precipitation method for barium metaborate (BaB2O4) synthesis from borax solution

    NASA Astrophysics Data System (ADS)

    Akşener, Eymen; Figen, Aysel Kantürk; Pişkin, Sabriye

    2013-12-01

    In this study, barium metaborate (BaB2O4, BMB) synthesis from the borax solution was carried out. BMB currently is used in production of ceramic glazes, luminophors, oxide cathodes as well as additives to pigments for aqueous emulsion paints and also β-BaB2O4 single crystals are the best candidate for fabrication of solid-state UV lasers operating at a wavelength of 200 nm due to excellent nonlinear optical properties. In the present study, synthesis was carried out from the borax solution (Na2B4O7ṡ10H2O, BDH) and barium chloride (BaCI2ṡ2H2O, Ba) in the glass-batch reactor with stirring. The effect of, times (5-15 min), molar ratio [stoich.ration (1.0:2.0), 1.25:2.0, 1.5:2.0, 2.5:2:0, 3.0:2.0, 3.5:2.0,4.0:2.0, 5.0:2.0] and also crystallization time (2-6 hour) on the BMB yield (%) was investigated at 80 °C reaction temperature. It is found that, BMB precipitation synthesis with 90 % yield can be performed from 0.50 molar ration (BDH:Ba), under 80 °C, 15 minute, and 6 hours crystallization time. The structural properties of BMB powders were characterized by using XRD, FT-IR and DTA-TG instrumental analysis technique.

  12. Investigation on a new scleroglucan/borax hydrogel: structure and drug release.

    PubMed

    Palleschi, Antonio; Coviello, Tommasina; Bocchinfuso, Gianfranco; Alhaique, Franco

    2006-09-28

    The aim of this work is to elucidate the structure of the new hydrogel prepared with scleroglucan (Sclg) and borax, suitable for drug delivery, applying theoretical approaches, and to explain its very peculiar swelling. The possible linkages with borate ions have been investigated and original parameters for the 4,6-gluco-borate moiety have been introduced. The structures relative to the Sclg chains in the presence of borax and the possible mutual arrangements among the triple helices are given. According to molecular dynamics simulations, the most probable assembly of the chains in the network is proposed, without and in the presence of three tested model drugs with different molecular dimensions: theophylline (TPH), Vitamin B12 (Vit. B12) and myoglobin (MGB). The hydrogel supramolecular structure, formed via chemical and physical linkages among the polysaccharidic chains, is built up taking into account the steric hindrance of the entrapped molecules. It is shown that molecular dynamics analysis can be a useful tool capable to shed some light on the anomalous swelling of the hydrogel, suitable for drug release, giving a new insight on the network structure and the release rate of the guest molecules. PMID:16806759

  13. ASSESSMENT OF BORIC ACID AND BORAX USING THE IEHR EVALUATIVE PROCESS FOR ASSESSING HUMAN DEVELOPMENT AND REPRODUCTIVE TOXICITY OF AGENTS

    EPA Science Inventory

    This document presents an evaluation of the reproductive and developmental effects of boric acid, H3803 (CAS Registry No. 10043-35-3) and disodium tetraborate decehydrate or borax, Na2B4O2O(CAS Registry No. 1303-96-4). he element, boron, does not exist naturally. oron always exis...

  14. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its... the requirement of a tolerance is established for residues of the pesticidal chemical boric acid...

  15. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its... the requirement of a tolerance is established for residues of the pesticidal chemical boric acid...

  16. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its... the requirement of a tolerance is established for residues of the pesticidal chemical boric acid...

  17. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its... the requirement of a tolerance is established for residues of the pesticidal chemical boric acid...

  18. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Boric acid and its salts, borax... EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES IN FOOD Exemptions From Tolerances § 180.1121 Boric acid and its... the requirement of a tolerance is established for residues of the pesticidal chemical boric acid...

  19. Preparation and characterization of antimicrobial wound dressings based on silver, gellan, PVA and borax.

    PubMed

    Cencetti, C; Bellini, D; Pavesio, A; Senigaglia, D; Passariello, C; Virga, A; Matricardi, P

    2012-10-15

    Silver-loaded dressings are designed to provide the same antimicrobial activity of topical silver, with the advantages of a sustained silver release and a reduced number of dressing changes. Moreover, such type of dressing must provide a moist environment, avoiding fiber shedding, dehydration and adherence to the wound site. Here we describe the preparation of a novel silver-loaded dressing based on a Gellan/Hyaff(®) (Ge-H) non woven, treated with a polyvinyl alcohol (PVA)/borax system capable to enhance the entrapment of silver in the dressing and to modulate its release. The new hydrophilic non woven dressings show enhanced water uptake capability and slow dehydration rates. A sustained silver release is also achieved. The antibacterial activity was confirmed on Staphylococcus aureus and Pseudomonas aeruginosa. PMID:22939352

  20. Total cost of 46-Mw Borax cogen system put at $30M

    SciTech Connect

    de Biasi, V.

    1983-03-01

    The cogeneration system, designed around a W-251B gas turbine power plant exhausting into a Deltak waste heat boiler to produce ''free'' process steam from the gas turbine exhaust, is discussed. The design includes water injection for NO/sub x/ control, self-cleaning inlet air filters, evaporative coolers, supercharger, and supplementary firing of the waste heat boiler. Once the system is operational Borax will be able to generate all of the electricity needed for on-site operations and a large share of process steam needs--plus still have 22-23 Mw surplus electric power to sell, so that the installation should pay for itself in less than 5 years of service.

  1. Experimenting with cameraless photography using turmeric and borax: an introduction to photophysics

    NASA Astrophysics Data System (ADS)

    Appleyard, S. J.

    2012-07-01

    An alcoholic extract of the spice turmeric can be used to create a light-sensitive dye that can be used to stain paper. On exposure to sunlight, the dyed paper can be used to capture photographic images of flat objects or reproduce existing images through the preferential degradation of the dye in light-exposed areas over a time period of a few hours. The images can be developed and preserved by spraying the exposed paper with a dilute solution of borax, which forms coloured organo-boron complexes that limit further degradation of the dye and enhance the colour of the image. Similar photochemical reactions that lead to the degradation of the turmeric dye can also be used for reducing the organic pollution load in wastewater produced by many industrial processes and in dye-sensitized solar cells for producing electricity.

  2. Borax in the supraglacial moraine of the Lewis Cliff, Buckley Island quadrangle--first Antarctic occurrence

    USGS Publications Warehouse

    Fitzpatrick, J.J.; Muhs, D.R.

    1989-01-01

    During the 1987-1988 austral summer field season, membersof the south party of the antarctic search for meteorites south-ern team* working in the Lewis Cliff/Colbert Hills region dis-covered several areas of unusual mineralization within theLewis Cliff ice tongue and its associated moraine field (figure1). The Lewis Cliff ice tongue (84°15'S 161°25'E) is a meteorite-stranding surface of ablating blue ice, about 2.3 by 7.0 kilo-meters, bounded on the west by the Lewis Cliff, on the northand northeast by a large supraglacial moraine, and on the eastby the Colbert Hills. To the south it opens to the Walcott Névé.Because it is a meteorite-stranding surface, the major component of ice motion in the area is believed to be vertical(Whillans and Cassidy 1983). The presence of Thule-Baffinmoraines at the northern terminus of the blue ice tends tosupport the hypothesis that the area underlying the moraineis essentially stagnant and that ice arriving from the south ispiling up against it. Areas containing mineral deposits werefound within the moraine field to the north and east of theblue ice margin and also along the east margins of the blue iceitself. Subsequent X-ray diffraction analyses of these depositshave shown that they are composed predominantly of nah-colite (NaHCO3), trona [Na3(CO3)(HCO3) · 2H20], borax[Na2B405(OH)4 · 8H20], and a new hexagonal hydrous sulfatespecies. This paper reports the details of the borax occurrence,because it is the first known on the continent.

  3. Compared production behavior of borax and unborax premixed SiC reinforcement Al7Si-Mg-TiB alloys composites with semi-solid stir casting method

    NASA Astrophysics Data System (ADS)

    Haryono, M. B.; Sulardjaka, Nugroho, Sri

    2016-04-01

    The present study was aimed to investigate the effect of borax additive on physical and mechanical properties of Al7Si-Mg-TiB with the reinforcement of silicon carbide. In this case, the different weight percentage from the reinforcement of SiC (10, 15, and 20% wt), and the borax additive (ratio 1:4) were homogenously added into the matrix by employing the semi-solid stir casting method at the temperature of 590°C. Al7Si-Mg-TiB melted in an electric resistance furnace at 800°C for 25 minutes and the holding time of 5 minutes; SiC was stirred with borax inside the chamber and heated at the temperature of 250°C for 25 minutes. Then, it melted by lowing the temperature into 590°C. The SiC-borax mixture was added into the electric resistance furnace, and automatically stirred by the stirrer at a constant speed (500 rpm for 3 minutes) in the composite A17Si-Mg-TiB. It melted when heated at 750°C for 17minutes,then, casting was performed on the prepared mould. The characterizations of Al7Si-Mg-TiB-SiC/borax were porosity, hardness, and microstructure on the Al7Si-Mg-TiB-SiC/ borax. The porosity of AMC tended to increase along with the increaseof the wt% SiC (1.4%-3.6%); however, borax additive underwent a decrease in porosity (0.14%-1.3%). Further, hardness tended to improve along with the increase of wt% SiC. The unboraxmixture had 79,6 HRB up to 94 HRB. Whereas, the borax additive mixture had 105,8 HRB up to 121 HRB.

  4. In vitro studies on chemoprotective effect of borax against aflatoxin B1-induced genetic damage in human lymphocytes.

    PubMed

    Turkez, Hasan; Geyikoğlu, Fatime; Dirican, Ebubekir; Tatar, Abdulgani

    2012-12-01

    A common dietary contaminant, aflatoxin B1 (AFB1), has been shown to be a potent mutagen and carcinogen in humans and many animal species. Since the eradication of AFB1 contamination in agricultural products has been rare, the use of natural or synthetic free radical scavengers could be a potential chemopreventive strategy. Boron compounds like borax (BX) and boric acid are the major components of industry and their antioxidant role has recently been reported. In the present report, we evaluated the capability of BX to inhibit the rate of micronucleus (MN) and sister chromatid exchange (SCE) formations induced by AFB1. There were significant increases (P < 0.05) in both SCE and MN frequencies of cultures treated with AFB1 (3.12 ppm) as compared to controls. However, co-application of BX (1, 2 and 5 ppm) and AFB1 resulted in decreases of SCE and MN rates as compared to the group treated with AFB1 alone. Borax gave 30-50 % protection against AFB1 induced SCEs and MNs. In conclusion, the support of borax was especially useful in aflatoxin-toxicated blood tissue. Thus, the risk on target tissues of AFB1 could be reduced and ensured early recovery from its toxicity. PMID:22526492

  5. Impact of the propylene glycol-water-borax coolant on material recovery operations

    SciTech Connect

    Duerksen, W.K.; Taylor, P.A.

    1983-05-01

    The reaction of the propylene glycol-water-borax coolant with nitric acid has now been studied in some detail. This document is intended to provide a summary of the results. Findings are summarized under nine headings. Tests have also been conducted to determine if the new coolant would have any adverse effects on the uranium recycle systems. Experiments were scientifically designed after observation of the production operations so that accurate response to the immediate production concerns could be provided. Conclusions from these studies are: formation of glycol nitrates is very improbable; the reaction of concentrated (70%) nitric acid with pure propylene glycol is very violent and hazardous; dilution of the nitric acid-glycol mixture causes a drastic decrease in the rate and intensity of the reaction; the mechanism of the nitric acid propylene glycol reaction is autocatalytic in nitrous acid; no reaction is observed between coolant and 30% nitric acid unless the solution is heated; the coolant reacts fairly vigorously with 55% nitric acid after a concentration-dependent induction time; experiments showed that the dissolution of uranium chips that had been soaked in coolant proceeded at about the same rate as if the chips had not previously contacted glycol; thermodynamic calculations show that the enthalpy change (heat liberated) by the reaction of nitric acid (30%) with propylene glycol is smaller than if the same amount of nitric acid reacted with uranium. Each of these conclusions is briefly discussed. The effect of new coolant on uranium recycle operations is then briefly discussed.

  6. Pulsed laser ablation of borax target in vacuum and hydrogen DC glow discharges

    NASA Astrophysics Data System (ADS)

    Kale, A. N.; Miotello, A.; Mosaner, P.

    2006-09-01

    The aim of our experiment was to produce a material with B sbnd H bonds for applications in hydrogen storage and generation. By using KrF excimer laser ( λ = 248 nm) ablation of borax (Na 2B 4O 7) target, thin films were deposited on KBr and silicon substrates. Ablation was performed both in vacuum and in hydrogen atmosphere. DC glow discharge technique was utilized to enhance hydrogen gas ionization. Experiments were performed using laser fluence from 5 to 20 J/cm 2. Films were deposited under gas pressure of 1 × 10 -5 to 5 × 10 -2 mbar and substrate temperatures of 130-450 °C. Scanning electron microscopy analysis of films showed presence of circular particulates. Film thickness, roughness and particulates number increased with increase in laser fluence. Energy dispersive X-ray spectroscopy analysis shows that sodium content in the particulates is higher than in the target. This effect is discussed in terms of atomic arrangements (both at surface and bulk) in systems where ionic and covalent bonds are present and by looking at the increased surface/bulk ratio of the particulates with respect to the deposited films. The Fourier transform infrared spectroscopy measurements showed presence of B sbnd O stretching and B sbnd O sbnd B bending bonds. Possible reasons for absence of B sbnd H bonds are attributed to binding enthalpy of the competing molecules.

  7. A new scleroglucan/borax hydrogel: swelling and drug release studies.

    PubMed

    Coviello, Tommasina; Grassi, Mario; Palleschi, Antonio; Bocchinfuso, Gianfranco; Coluzzi, Gina; Banishoeib, Fateme; Alhaique, Franco

    2005-01-31

    The aim of the work was the characterization of a new polysaccharidic physical hydrogel, obtained from Scleroglucan (Sclg) and borax, following water uptake and dimension variations during the swelling process. Furthermore, the release of molecules of different size (Theophylline (TPH), Vitamin B12 (Vit. B12) and Myoglobin (MGB)) from the gel and from the dried system used as a matrix for tablets was studied. The increase of weight of the tablets with and without the loaded drugs was followed together with the relative variation of the dimensions. The dry matrix, in the form of tablets was capable, during the swelling process, to incorporate a relevant amount of solvent (ca. 20 g water/g dried matrix), without dissolving in the medium, leading to a surprisingly noticeable anisotropic swelling that can be correlated with a peculiar supramolecular structure of the system induced by compression. Obtained results indicate that the new hydrogel can be suitable for sustained drug release formulations. The delivery from the matrix is deeply dependent on the size of the tested model drugs. The experimental release data obtained from the gel were satisfactorily fitted by an appropriate theoretical approach and the relative drug diffusion coefficients in the hydrogel were estimated. The release profiles of TPH, Vit. B12 and MGB from the tablets have been analyzed in terms of a new mathematical approach that allows calculating of permeability values of the loaded drugs. PMID:15652203

  8. mm-wave antenna

    NASA Astrophysics Data System (ADS)

    Muhs, H. P.

    1985-07-01

    The present low profile seeker front end's slotted waveguide antenna was primarily developed to investigate the feasibility of the application of standard manufacturing techniques to mm-wave hardware. A dual plane monopulse comparator was constructed to mate with the antenna via integrated packaging techniques. The comparator was fabricated by CAD/CAM milling operations.

  9. Characterization of two glycoside hydrolase family 36 α-galactosidases: novel transglycosylation activity, lead-zinc tolerance, alkaline and multiple pH optima, and low-temperature activity.

    PubMed

    Zhou, Junpei; Lu, Qian; Zhang, Rui; Wang, Yiyan; Wu, Qian; Li, Junjun; Tang, Xianghua; Xu, Bo; Ding, Junmei; Huang, Zunxi

    2016-03-01

    Two α-galactosidases, AgaAJB07 from Mesorhizobium and AgaAHJG4 from Streptomyces, were expressed in Escherichia coli. Recombinant AgaAJB07 showed a 2.9-fold and 22.6-fold increase in kcat with a concomitant increase of 2.3-fold and 16.3-fold in Km in the presence of 0.5mM ZnSO4 and 30.0mM Pb(CH3COO)2, respectively. Recombinant AgaAHJG4 showed apparent optimal activity at pH 8.0 in McIlvaine or Tris-HCl buffer and 9.5 in glycine-NaOH or HCl-borax-NaOH buffer, retention of 23.6% and 43.2% activity when assayed at 10 and 20°C, respectively, and a half-life of approximately 2min at 50°C. The activation energies for p-nitrophenyl-α-d-galactopyranoside hydrolysis by AgaAJB07 and AgaAHJG4 were 71.9±0.8 and 48.2±2.0kJmol(-1), respectively. Both AgaAJB07 and AgaAHJG4 exhibited transglycosylation activity, but they required different acceptors and produced different compounds. Furthermore, potential factors for alkaline and multiple pH optima and low-temperature adaptations of AgaAHJG4 were presumed. PMID:26471539

  10. Mg- and K-bearing borates and associated evaporites at Eagle Borax spring, Death Valley, California: A spectroscopic exploration

    USGS Publications Warehouse

    Crowley, J.K.

    1996-01-01

    Efflorescent crusts at the Eagle Borax spring in Death Valley, California, contain an array of rare Mg and K borate minerals, several of which are only known from one or two other localities. The Mg- and/or K-bearing borates include aristarainite, hydroboracite, kaliborite, mcallisterite, pinnoite, rivadavite, and santite. Ulexite and probertite also occur in the area, although their distribution is different from that of the Mg and K borates. Other evaporite minerals in the spring vicinity include halite, thenardite, eugsterite, gypsum-anhydrite, hexahydrite, and bloedite. Whereas the first five of these minerals are found throughout Death Valley, the last two Mg sulfates are more restricted in occurrence and are indicative of Mg-enriched ground water. Mineral associations observed at the Eagle Borax spring, and at many other borate deposits worldwide, can be explained by the chemical fractionation of borate-precipitating waters during the course of evaporative concentration. The Mg sulfate and Mg borate minerals in the Eagle Borax efflorescent crusts point to the fractionation of Ca by the operation of a chemical divide involving Ca carbonate and Na-Ca borate precipitation in the subsurface sediments. At many other borate mining localities, the occurrence of ulexite in both Na borate (borax-kernite) and Ca borate (ulexite-colemanite) deposits similarly reflects ulexite's coprecipitation with Ca carbonate at an early concentration stage. Such ulexite may perhaps be converted to colemanite by later reaction with the coexisting Ca carbonate - the latter providing the additional Ca2+ ions needed for the conversion. Mg and Ca-Mg borates are the expected late-stage concentration products of waters forming ulexite-colemanite deposits and are therefore most likely to occur in the marginal zones or nearby mud facies of ulexite-colemanite orebodies. Under some circumstances, Mg and Ca-Mg borates might provide a useful prospecting guide for ulexite-colemanite deposits

  11. High-compactness coating grown by plasma electrolytic oxidation on AZ31 magnesium alloy in the solution of silicate-borax

    NASA Astrophysics Data System (ADS)

    Shen, M. J.; Wang, X. J.; Zhang, M. F.

    2012-10-01

    A ceramic coating was formed on the surface of AZ31 magnesium alloy by plasma electrolytic oxidation (PEO) in the silicate solution with and without borax doped. The composition, morphology, elements and roughness as well as mechanical property of the coating were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and reciprocal-sliding tribometer. The results show that the PEO coating is mainly composed of magnesia. When using borax dope, boron element is permeating into the coating and the boron containing phase exist in the form of amorphous. In addition, the microhardness and compactness of the PEO coating are improved significantly due to doped borax.

  12. Preparing high- and low-aspect ratio AlB2 flakes from borax or boron oxide

    NASA Astrophysics Data System (ADS)

    Hall, A. C.; Economy, J.

    2000-02-01

    The commercial preparation of aluminum-diboride flakes in aluminum relies on relatively expensive starting materials. A new synthesis has been developed that allows AlB2 to be prepared directly from the reaction of borax (Na2B4O7·10H2O) or boron oxide (B2O3) with aluminum. Aluminum metal at temperatures higher than 900°C has been shown to reduce these boron-containing compounds, producing an Al2O3-containing slag and AlB2. A natural separation occurs, leaving AlB2 in the molten aluminum and Al2O3 as part of a slag that forms at the melt surface. Samples containing up to 10 vol.% AlB2 in an aluminum matrix have been directly prepared using this method.

  13. Precipitation method for barium metaborate (BaB{sub 2}O{sub 4}) synthesis from borax solution

    SciTech Connect

    Akşener, Eymen; Figen, Aysel Kantürk; Pişkin, Sabriye

    2013-12-16

    In this study, barium metaborate (BaB{sub 2}O{sub 4}, BMB) synthesis from the borax solution was carried out. BMB currently is used in production of ceramic glazes, luminophors, oxide cathodes as well as additives to pigments for aqueous emulsion paints and also β−BaB{sub 2}O{sub 4} single crystals are the best candidate for fabrication of solid-state UV lasers operating at a wavelength of 200 nm due to excellent nonlinear optical properties. In the present study, synthesis was carried out from the borax solution (Na{sub 2}B{sub 4}O{sub 7⋅}10H{sub 2}O, BDH) and barium chloride (BaCI{sub 2⋅}2H{sub 2}O, Ba) in the glass-batch reactor with stirring. The effect of, times (5-15 min), molar ratio [stoich.ration (1.0:2.0), 1.25:2.0, 1.5:2.0, 2.5:2:0, 3.0:2.0, 3.5:2.0,4.0:2.0, 5.0:2.0] and also crystallization time (2-6 hour) on the BMB yield (%) was investigated at 80 °C reaction temperature. It is found that, BMB precipitation synthesis with 90 % yield can be performed from 0.50 molar ration (BDH:Ba), under 80 °C, 15 minute, and 6 hours crystallization time. The structural properties of BMB powders were characterized by using XRD, FT-IR and DTA-TG instrumental analysis technique.

  14. Primeval galaxies in the sub-mm and mm

    NASA Technical Reports Server (NTRS)

    Bond, J. Richard; Myers, Steven T.

    1993-01-01

    Although the results of COBE's FIRAS experiment 1 constrain the deviation in energy from the CMB blackbody in the 500-5000 micron range to be delta E/E, sub cmb less than 0.005, primeval galaxies can still lead to a brilliant sub-mm sky of non-Gaussian sources that are detectable at 10 inch resolution from planned arrays such as SCUBA on the James Clerk Maxwell Telescope and, quite plausibly, at sub-arcsecond resolution in planned mm and sub-mm interferometers. Here, we apply our hierarchical peaks method to a CDM model to construct sub-mm and mm maps of bursting PG's appropriate for these instruments with minimum contours chosen to correspond to realistic observational parameters for them and which pass the FIRAS limits.

  15. OpenMM accelerated MMTK

    NASA Astrophysics Data System (ADS)

    Bishop, Kevin P.; Constable, Steve; Faruk, Nabil F.; Roy, Pierre-Nicholas

    2015-06-01

    In this work, we provide an interface developed to link the Molecular Modelling toolkit (MMTK) with OpenMM in order to take advantage of the fast evaluation techniques of OpenMM. This interface allows MMTK scripts using the Langevin dynamics integrator, for both classical and path integral simulations, to be executed on a variety of hardware including graphical processing units via OpenMM. The interface has been developed using Python and Cython to take advantage of the high level abstraction thanks to the MMTK and OpenMM software packages. We have tested the interface on a number of systems to observe which systems benefit most from the acceleration libraries of OpenMM.

  16. SSC 40 mm cable results and 50 mm design discussions

    SciTech Connect

    Christopherson, D.; Capone, D.; Hannaford, R.; Remsbottom, R.; Jayakumar, R.; Snitchler, G. ); Scanlan, R.; Royet, J. )

    1990-09-01

    A summary of the cable produced for the 1990 40 mm Dipole Program is presented. The cable design parameters for the 50 mm Dipole Program are discussed, as well as portions of the SSC specification draft. Considerations leading to the final cable configuration and the results of preliminary trials are included. The first iteration of a strand mapping program to automate cable strand maps is introduced. 7 refs., 2 figs., 1 tab.

  17. 3D Seismic and Magnetic characterization of the Borax Lake Hydrothermal System in the Alvord Desert, southeastern Oregon.

    NASA Astrophysics Data System (ADS)

    Hess, S.; Bradford, J.; Lyle, M.; Routh, P.; Liberty, L.; Donaldson, P.

    2004-05-01

    As part of an interdisciplinary project aiming to study the link between the physical characteristics of hydrothermal systems and biota that occupy those systems, we are conducting a detailed geophysical characterization of an active hydrothermal system. The Borax Lake Hydrothermal System (BLHS), consisting of Borax Lake and the surrounding hot springs. BLHS is located near the center of the Alvord Basin in southeastern Oregon. The Alvord Basin is a north-south trending graben in the Northern Great Basin bounded by the Steens Mountains to the west and the Trout Creek Mountains to the east. We conducted a 2D seismic survey to characterize the geologic structure of the basin, a high-resolution 3D seismic survey to characterize the geologic structure of the BLHS, and a high-resolution 3D magnetic survey to characterize any lineaments in the bedrock that might control fluid flow in the BLHS. Previous results from the 2D seismic survey show a mid-basin basement high aligned approximately with the hot springs. In this study we present the results from the high-resolution 3D seismic and magnetic survey of the BLHS. We acquired the 3D seismic data using an SKS rifle and 240 channel recording system. The seismic survey covers approximately 90,000 sq. m with a maximum inline offset aperture of 225 m, crossline aperture of 75 m, and 360 degree azimuthal coverage. The coincidental magnetic survey was collected using a Geometrics 858G cesium vapor magnetometer. We designed both surveys to span nearly 100 active hydrothermal springs, including an approximately 50 m stepover in the trend of the surface expression of the hot springs. After preliminary processing, the 3D seismic data show continuous reflections up to 300 ms (~ 480 m). The initial interpretation of features seen in the 3D data cube include: normal faults dipping to the east and west, near-surface disturbances that are consistent with the trend of the hot springs, and significant near surface velocity anomalies

  18. Microfibrillated cellulose and borax as mechanical, O₂-barrier, and surface-modulating agents of pullulan biocomposite coatings on BOPP.

    PubMed

    Cozzolino, Carlo A; Campanella, Gaetano; Türe, Hasan; Olsson, Richard T; Farris, Stefano

    2016-06-01

    Multifunctional composite coatings on bi-oriented polypropylene (BOPP) films were obtained using borax and microfibrillated cellulose (MFC) added to the main pullulan coating polymer. Spectroscopy analyses suggested that a first type of interaction occurred via hydrogen bonding between the C6OH group of pullulan and the hydroxyl groups of boric acid, while monodiol and didiol complexation represented a second mechanism. The deposition of the coatings yielded an increase in the elastic modulus of the entire plastic substrate (from ∼2GPa of the neat BOPP to ∼3.1GPa of the P/B+/MFC-coated BOPP). The addition of MFC yielded a decrease of both static and kinetic coefficients of friction of approximately 22% and 25%, respectively, as compared to the neat BOPP. All composite coatings dramatically increased the oxygen barrier performance of BOPP, especially under dry conditions. The deposition of the high hydrophilic coatings allowed to obtain highly wettable surfaces (water contact angle of ∼18°). PMID:27083358

  19. The GBT 4mm Receiver

    NASA Astrophysics Data System (ADS)

    Frayer, David T.; White, S.; Watts, G.; Stennes, M.; Maddalena, R. J.; Simon, R.; Pospieszalski, M.; Bryerton, E.

    2013-01-01

    The new 4mm receiver (67--93 GHz) for the Robert C. Byrd Green Bank Telescope (GBT) was built to take advantage of the improved surface accuracy of the dish. The low frequency end of the 3mm atmospheric window is not available with ALMA (<84 GHz), and the sensitivity of the GBT is better than any other facility within this band. We discuss the design and performance of this new receiver for the GBT, and highlight the science opportunities available with the instrument. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  20. Apollo 12 photography 70 mm, 16 mm, and 35 mm frame index

    NASA Technical Reports Server (NTRS)

    1970-01-01

    For each 70-mm frame, the index presents information on: (1) the focal length of the camera, (2) the photo scale at the principal point of the frame, (3) the selenographic coordinates at the principal point of the frame, (4) the percentage of forward overlap of the frame, (5) the sun angle (medium, low, high), (6) the quality of the photography, (7) the approximate tilt (minimum and maximum) of the camera, and (8) the direction of tilt. A brief description of each frame is also included. The index to the 16-mm sequence photography includes information concerning the approximate surface coverage of the photographic sequence and a brief description of the principal features shown. A column of remarks is included to indicate: (1) if the sequence is plotted on the photographic index map and (2) the quality of the photography. The pictures taken using the lunar surface closeup stereoscopic camera (35 mm) are also described in this same index format.

  1. Confirmatory radiological survey of the BORAX-V turbine building Idaho National Engineering Laboratory, Idaho Falls, Idaho

    SciTech Connect

    Stevens, G.H.; Coleman, R.L.; Jensen, M.K.; Pierce, G.A.; Egidi, P.V.; Mather, S.K.

    1993-07-01

    An independent assessment of the remediation of the BORAX-V (Boiling Water Reactor Experiment) turbine building at the Idaho National Engineering Laboratory (INEL), Idaho Falls, Idaho, was accomplished by the Oak Ridge National Laboratory Pollutant Assessments Group (ORNL/PAG). The purpose of the assessment was to confirm the site`s compliance with applicable Department of Energy guidelines. The assessment included reviews of both the decontamination and decommissioning Plan and data provided from the pre- and post-remedial action surveys and an independent verification survey of the facility. The independent verification survey included determination of background exposure rates and soil concentrations, beta-gamma and gamma radiation scans, smears for detection of removable contamination, and direct measurements for alpha and beta-gamma radiation activity on the basement and mezzanine floors and the building`s interior and exterior walls. Soil samples were taken, and beta-gamma and gamma radiation exposure rates were measured on areas adjacent to the building. Results of measurements on building surfaces at this facility were within established contamination guidelines except for elevated beta-gamma radiation levels located on three isolated areas of the basement floor. Following remediation of these areas, ORNL/PAG reviewed the remedial action contractor`s report and agreed that remediation was effective in removing the source of the elevated direct radiation. Results of all independent soil analyses for {sup 60}Co were below the detection limit. The highest {sup 137}Cs analysis result was 4.6 pCi/g; this value is below the INEL site-specific guideline of 10 pCi/g.

  2. Variable Selection using MM Algorithms

    PubMed Central

    Hunter, David R.; Li, Runze

    2009-01-01

    Variable selection is fundamental to high-dimensional statistical modeling. Many variable selection techniques may be implemented by maximum penalized likelihood using various penalty functions. Optimizing the penalized likelihood function is often challenging because it may be nondifferentiable and/or nonconcave. This article proposes a new class of algorithms for finding a maximizer of the penalized likelihood for a broad class of penalty functions. These algorithms operate by perturbing the penalty function slightly to render it differentiable, then optimizing this differentiable function using a minorize-maximize (MM) algorithm. MM algorithms are useful extensions of the well-known class of EM algorithms, a fact that allows us to analyze the local and global convergence of the proposed algorithm using some of the techniques employed for EM algorithms. In particular, we prove that when our MM algorithms converge, they must converge to a desirable point; we also discuss conditions under which this convergence may be guaranteed. We exploit the Newton-Raphson-like aspect of these algorithms to propose a sandwich estimator for the standard errors of the estimators. Our method performs well in numerical tests. PMID:19458786

  3. High-water-content mouldable polyvinyl alcohol-borax hydrogels reinforced by well-dispersed cellulose nanoparticles: dynamic rheological properties and hydrogel formation mechanism.

    PubMed

    Han, Jingquan; Lei, Tingzhou; Wu, Qinglin

    2014-02-15

    Cellulose nanoparticle (CNP) reinforced polyvinyl alcohol-borax (PB) hydrogels were produced via a facile approach in an aqueous system. The effects of particle size, aspect ratio, crystal structure, and surface charge of CNPs on the rheological properties of the composite hydrogels were investigated. The rheological measurements confirmed the incorporation of well-dispersed CNPs to PB system significantly enhanced the viscoelasticity and stiffness of hydrogels. The obtained free-standing, high elasticity and mouldable hydrogels exhibited self-recovery under continuous step strain and thermo-reversibility under temperature sweep. With the addition of cellulose I nanofibers, a 19-fold increase in the high-frequency plateau of storage modulus was obtained compared with that of the pure PB. CNPs acted as multifunctional crosslinking agents and nanofillers to physically and chemically bridge the 3D network hydrogel. The plausible mechanism for the multi-complexation between CNPs, polyvinyl alcohol and borax was proposed to understand the relationship between the 3D network and hydrogel properties. PMID:24507286

  4. Apollo 12 70 mm photographic catalog

    NASA Technical Reports Server (NTRS)

    1970-01-01

    Proof prints of the 70-mm photography are presented, sorted by magazine and frame number. The 28 lunar surface panorama mosaics and a listing of the mosaics are included. The catalog is designed to be used in conjunction with the "Apollo 12 Photography: 70-mm, 16-mm, and 35-mm Frame Index', which makes it possible to locate the area covered by each frame.

  5. Functional photoacoustic microscopy of pH

    NASA Astrophysics Data System (ADS)

    Chatni, M. Rameez; Yao, Junjie; Danielli, Amos; Favazza, Christopher P.; Maslov, Konstantin I.; Wang, Lihong V.

    2012-02-01

    pH is a tightly regulated indicator of metabolic activity. In mammalian systems, imbalance of pH regulation may result from or result in serious illness. Even though the regulation system of pH is very robust, tissue pH can be altered in many diseases such as cancer, osteoporosis and diabetes mellitus. Traditional high-resolution optical imaging techniques, such as confocal microscopy, routinely image pH in cells and tissues using pH sensitive fluorescent dyes, which change their fluorescence properties with the surrounding pH. Since strong optical scattering in biological tissue blurs images at greater depths, high-resolution pH imaging is limited to penetration depths of 1mm. Here, we report photoacoustic microscopy (PAM) of commercially available pH-sensitive fluorescent dye in tissue phantoms. Using both opticalresolution photoacoustic microscopy (OR-PAM), and acoustic resolution photoacoustic microscopy (AR-PAM), we explored the possibility of recovering the pH values in tissue phantoms. In this paper, we demonstrate that PAM was capable of recovering pH values up to a depth of 2 mm, greater than possible with other forms of optical microscopy.

  6. Mercury Pollution from Small-Scale Gold Mining Can Be Stopped by Implementing the Gravity-Borax Method--A Two-Year Follow-Up Study from Two Mining Communities in the Philippines.

    PubMed

    Køster-Rasmussen, Rasmus; Westergaard, Maria L; Brasholt, Marie; Gutierrez, Richard; Jørs, Erik; Thomsen, Jane F

    2016-02-01

    Mercury is used globally to extract gold in artisanal and small-scale gold mining. The mercury-free gravity-borax method for gold extraction was introduced in two mining communities using mercury in the provinces Kalinga and Camarines Norte. This article describes project activities and quantitative changes in mercury consumption and analyzes the implementation with diffusion of innovations theory. Activities included miner-to-miner training; seminars for health-care workers, school teachers, and children; and involvement of community leaders. Baseline (2011) and follow-up (2013) data were gathered on mining practices and knowledge about mercury toxicology. Most miners in Kalinga converted to the gravity-borax method, whereas only a few did so in Camarines Norte. Differences in the nature of the social systems impacted the success of the implementation, and involvement of the tribal organization facilitated the shift in Kalinga. In conclusion, the gravity-borax method is a doable alternative to mercury use in artisanal and small-scale gold mining, but support from the civil society is needed. PMID:26463257

  7. Application of MM wave therapy in radiology

    SciTech Connect

    Avakian, R.S.; Gasparyan, L.V.

    1995-12-31

    The authors studied the effects of MM wave electromagnetic radiation influence on patients, affected by X-ray radiation during the reparation works after Chernobyl nuclear power plant exposure. They compared results of treatment of two groups of patients: (1) control group patients received only basis therapy; (2) testing group, 10 patients received basis therapy and MM wave influence. The authors used the wide band noise generator `Artsakh - 2` for local irradiation on the acupuncture points. Their data proved that low intensity MM waves have immunocorrective, antioxidant effects, and MM wave therapy is a perspective method for treatment of patients with radiological pathology.

  8. Multimedia contents production system (MM-CPS)

    NASA Astrophysics Data System (ADS)

    Roser, Miguel; Villegas, Paulo; Simon, Maria; Hernandez-Gil, J. F.; Aguado, Isidro

    1996-01-01

    A present characterized by deep worldwide changes, and a future where social relations and behaviors are going to undergo a substantial change need new telecommunications services in order to allow people to get closer, facilitate their daily tasks and place at their disposal multimedia information to be accessed anywhere and at any time. These new services are very dependent on the contents to be included in the applications. The purpose of this paper is to describe an universal MM contents production system (MM-CPS), which allows the generation of coded data files suitable to be included in MM-servers.

  9. MM Algorithms for Geometric and Signomial Programming.

    PubMed

    Lange, Kenneth; Zhou, Hua

    2014-02-01

    This paper derives new algorithms for signomial programming, a generalization of geometric programming. The algorithms are based on a generic principle for optimization called the MM algorithm. In this setting, one can apply the geometric-arithmetic mean inequality and a supporting hyperplane inequality to create a surrogate function with parameters separated. Thus, unconstrained signomial programming reduces to a sequence of one-dimensional minimization problems. Simple examples demonstrate that the MM algorithm derived can converge to a boundary point or to one point of a continuum of minimum points. Conditions under which the minimum point is unique or occurs in the interior of parameter space are proved for geometric programming. Convergence to an interior point occurs at a linear rate. Finally, the MM framework easily accommodates equality and inequality constraints of signomial type. For the most important special case, constrained quadratic programming, the MM algorithm involves very simple updates. PMID:24634545

  10. MM Algorithms for Geometric and Signomial Programming

    PubMed Central

    Lange, Kenneth; Zhou, Hua

    2013-01-01

    This paper derives new algorithms for signomial programming, a generalization of geometric programming. The algorithms are based on a generic principle for optimization called the MM algorithm. In this setting, one can apply the geometric-arithmetic mean inequality and a supporting hyperplane inequality to create a surrogate function with parameters separated. Thus, unconstrained signomial programming reduces to a sequence of one-dimensional minimization problems. Simple examples demonstrate that the MM algorithm derived can converge to a boundary point or to one point of a continuum of minimum points. Conditions under which the minimum point is unique or occurs in the interior of parameter space are proved for geometric programming. Convergence to an interior point occurs at a linear rate. Finally, the MM framework easily accommodates equality and inequality constraints of signomial type. For the most important special case, constrained quadratic programming, the MM algorithm involves very simple updates. PMID:24634545

  11. QM/MM Calculations on Proteins.

    PubMed

    Ryde, U

    2016-01-01

    In this chapter, I discuss combined quantum mechanics (QM) and molecular mechanics (MM; QM/MM) calculations for proteins. In QM/MM, a small but interesting part of the protein is treated by accurate QM methods, whereas the remainder is treated by faster MM methods. The prime problems with QM/MM calculations are bonds between the QM and MM systems, the selection of the QM system, and the local-minima problem. The two first problems can be solved by the big-QM approach, including in the QM calculation all groups within 4.5-6Å of the active site and all buried charges in the protein. The third problem can be solved by calculating free energies. It is important to study QM/MM energy components to ensure that the results are stable and reliable. They can also be used to understand the reaction and the effect of the surroundings, eg, by dividing the catalytic effect into bonded, van der Waals, electrostatic, and geometric components and to deduce which parts of the protein contribute most to the catalysis. It should be ensured that the QM calculations are reliable and converged by extending the basis set to quadruple-zeta quality, including a proper treatment of dispersion, as well as years experience and method development calculations with both pure and hybrid density functional theory methods. If the latter give differing results, calibration with high-level QM methods is needed. Reactions that change the net charge should be avoided. QM/MM calculations can be combined with experimental methods. PMID:27498637

  12. Dark filaments observed at 8.3mm and 3.1mm wavelength

    NASA Technical Reports Server (NTRS)

    Hiel, E.; Ishiguro, M.; Kosugi, T.; Shibasaki, K.

    1986-01-01

    Mapping of the sun was made at 3.1mm (98 GHz) and 8.3mm (36 GHz) wavelengths with a 45m dish radio telescope at the Nobeyama Cosmic Radio Observatory. The depressions associated with large H alpha filaments are derived to be -0.2 at 8.3mm and -0.05 at 3.1mm, which are darker than the values inferred by Raoult et al. (1979)

  13. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are... Subpart MM 1 Table 1 to Subpart MM of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  14. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are... Subpart MM 1 Table 1 to Subpart MM of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  15. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are... Subpart MM 1 Table 1 to Subpart MM of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  16. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are... Subpart MM 1 Table 1 to Subpart MM of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  17. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ....860. 63.1(b)(2) Title V operating permit—see 40 CFR part 70 Yes All major affected sources are... Subpart MM 1 Table 1 to Subpart MM of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  18. Laparoscopic cholecystectomy using 2-mm instruments.

    PubMed

    Uranüs, S; Peng, Z; Kronberger, L; Pfeifer, J; Salehi, B

    1998-10-01

    Today, laparoscopic cholecystectomy is the method of choice for treatment of symptomatic gallbladder disorders. It minimizes effects of the operation that are independent of the gallbladder, such as trauma to the abdominal wall and other soft tissue. The surgical wounds were even smaller when 2-mm trocars were used. Laparoscopic cholecystectomy using 2-mm instruments was performed in a consecutive series of 14 patients with symptomatic gallstones. The procedure was completed in 12 cases, with conversion to open surgery in two cases. Intraoperative cholangiography was always performed. The postoperative course was always uneventful. The cosmetic effect was highly satisfactory. The procedure using 2-mm instruments could be indicated in selected patients with uncomplicated gallstone disease. PMID:9820716

  19. Microeconomics of 300-mm process module control

    NASA Astrophysics Data System (ADS)

    Monahan, Kevin M.; Chatterjee, Arun K.; Falessi, Georges; Levy, Ady; Stoller, Meryl D.

    2001-08-01

    Simple microeconomic models that directly link metrology, yield, and profitability are rare or non-existent. In this work, we validate and apply such a model. Using a small number of input parameters, we explain current yield management practices in 200 mm factories. The model is then used to extrapolate requirements for 300 mm factories, including the impact of simultaneous technology transitions to 130nm lithography and integrated metrology. To support our conclusions, we use examples relevant to factory-wide photo module control.

  20. Optimizing digital 8mm drive performance

    NASA Technical Reports Server (NTRS)

    Schadegg, Gerry

    1993-01-01

    The experience of attaching over 350,000 digital 8mm drives to 85-plus system platforms has uncovered many factors which can reduce cartridge capacity or drive throughput, reduce reliability, affect cartridge archivability and actually shorten drive life. Some are unique to an installation. Others result from how the system is set up to talk to the drive. Many stem from how applications use the drive, the work load that's present, the kind of media used and, very important, the kind of cleaning program in place. Digital 8mm drives record data at densities that rival those of disk technology. Even with technology this advanced, they are extremely robust and, given proper usage, care and media, should reward the user with a long productive life. The 8mm drive will give its best performance using high-quality 'data grade' media. Even though it costs more, good 'data grade' media can sustain the reliability and rigorous needs of a data storage environment and, with proper care, give users an archival life of 30 years or more. Various factors, taken individually, may not necessarily produce performance or reliability problems. Taken in combination, their effects can compound, resulting in rapid reductions in a drive's serviceable life, cartridge capacity, or drive performance. The key to managing media is determining the importance one places upon their recorded data and, subsequently, setting media usage guidelines that can deliver data reliability. Various options one can implement to optimize digital 8mm drive performance are explored.

  1. MM-122: High speed civil transport

    NASA Technical Reports Server (NTRS)

    Demarest, Bill; Anders, Kurt; Manchec, John; Yang, Eric; Overgaard, Dan; Kalkwarf, Mike

    1992-01-01

    The rapidly expanding Pacific Rim market along with other growing markets indicates that the future market potential for a high speed civil transport is great indeed. The MM-122 is the answer to the international market desire for a state of the art, long range, high speed civil transport. It will carry 250 passengers a distance of 5200 nm at over twice the speed of sound. The MM-122 is designed to incorporate the latest technologies in the areas of control systems, propulsions, aerodynamics, and materials. The MM-122 will accomplish these goals using the following design parameters. First, a double delta wing planform with highly swept canards and an appropriately area ruled fuselage will be incorporated to accomplish desired aerodynamic characteristics. Propulsion will be provided by four low bypass variable cycle turbofan engines. A quad-redundant fly-by-wire flight control system will be incorporated to provide appropriate static stability and level 1 handling qualities. Finally, the latest in conventional metallic and modern composite materials will be used to provide desired weight and performance characteristics. The MM-122 incorporates the latest in technology and cost minimization techniques to provide a viable solution to this future market potential.

  2. CCM3 to MM5 Data Conversion

    Energy Science and Technology Software Center (ESTSC)

    2007-03-02

    The accompanying script (which uses the NCAR Command Language) ready output from the Community Climate Model Code, version 3 (CCM3) and converts it to input format for the Mesoscale Model, version 5 (MM5) code. The script utilizes a Fortran binary write routine.

  3. Mm-wave power meter mount

    NASA Technical Reports Server (NTRS)

    Mullen, D. L.; Oltmans, D. A.; Stelzried, C. T.

    1968-01-01

    E-band thermistor mount and a technique for adjusting a temperature compensating thermistor to provide an electrically balanced bridge are used for measuring RF power in the mm-wavelength. The mount is relatively insensitive to temperature effects that cause measurement errors in single ended circuits.

  4. A New Laboratory for MM-/Sub-MM-Wave Characterization of Cosmic Dust Analogs

    NASA Astrophysics Data System (ADS)

    Birsa, Samuel; Do, Huy; Williams, Frederick; Liu, Lunjun; Schonert, Ryan; Perera, Thushara

    2015-01-01

    Most studies conducted with observatories such as ALMA, SOFIA, PLANCK, and Herschel will benefit from knowledge of (1) the predominant cosmic dust species in various environments, in terms of composition and structure and (2) mm/sub-mm optical properties of cosmic dusts, including the temperature dependent-emissivity and spectral index. A new laboratory has been established for producing and characterizing (in the mm/sub-mm) various silicate/carbonaceous dust candidates. In particular, the optical measurement setup was custom designed, specifically for laboratory studies of dusts, using techniques borrowed from observational cosmology. It features novel designs for a compact Fourier Transform Spectrometer (FTS) and a cold sample holder/exchanger. Construction of this apparatus is now complete; we are currently testing the system. Here, we present the mm/sub-mm measurement scheme and highlight its innovative and aspects.

  5. Comparison between 28 mm and 32 mm ceramic-on-ceramic bearings in total hip replacement.

    PubMed

    Lee, Y K; Ha, Y C; Koo, K H

    2014-11-01

    Large femoral heads have become popular in total hip replacement (THR) as a method of reducing the risk of dislocation. However, if large heads are used in ceramic-on-ceramic THR, the liner must be thinner, which may increase the risk of fracture. To compare the rates of ceramic fracture and dislocation between 28 mm and 32 mm ceramic heads, 120 hips in 109 patients (51 men and 58 women, mean age 49.2 years) were randomised to THR with either a 28 mm or a 32 mm ceramic articulation. A total of 57/60 hips assigned to the 28 mm group and 55/60 hips assigned to the 32 mm group were followed for at least five years. No ceramic component fractures occured in any patient in either group. There was one dislocation in the 32 mm group and none in the 28 mm group (p = 0.464). No hip had detectable wear, focal osteolysis or prosthetic loosening. In our small study the 32 mm ceramic articulation appeared to be safe in terms of ceramic liner fracture. PMID:25371457

  6. Development of mini-tablets with 1mm and 2mm diameter.

    PubMed

    Tissen, Corinna; Woertz, Katharina; Breitkreutz, Joerg; Kleinebudde, Peter

    2011-09-15

    The feasibility of formulating mini-tablets with 1mm diameter on a rotary-die press in comparison to mini-tablets of 2mm was investigated. To gain insight into the production of 1mm mini-tablets, three model drugs of different compression characteristics were chosen, namely quinine hydrochloride, ibuprofen and spray-dried gentian extract. A high drug load in combination with robust and reproducible mechanical properties was requested. Depending on the individual drug substance, mini-tablets were produced by direct compression or after roll-compaction/dry granulation. The tensile strength, mass, and their variation coefficients were determined to assess the mechanical properties of the tablets. The content uniformity and the dissolution behavior of selected batches were analyzed. For the first time 1mm mini-tablets could be successfully produced by direct compression (90% quinine hydrochloride; 90% dried gentian extract) and after roll compaction (70% ibuprofen). Depending on the applied compression pressure, 1mm mini-tablets with quinine hydrochloride exhibited robust mechanical properties (e.g. median tensile strength of 2.02N/mm(2)) with equal or lower variance of distribution compared to the 2mm compacts. With respect to content uniformity of dosage forms, 1mm mini-tablets containing 80% quinine hydrochloride met the requirements of the European Pharmacopeia (AV=6.8). PMID:21726616

  7. Effect of the borax mass and pre-spray medium temperature on droplet size and velocity vector distributions of intermittently sprayed starchy solutions.

    PubMed

    Naz, Muhammad Yasin; Sulaiman, Shaharin Anwar; Ariwahjoedi, Bambang

    2015-02-01

    Spray coating technology has demonstrated great potential in the slow release fertilizers industry. The better understanding of the key spray parameters benefits both the environment and low cost coating processes. The use of starch based materials to coat the slow release fertilizers is a new development. However, the hydraulic spray jet breakup of the non-Newtonian starchy solutions is a complex phenomenon and very little known. The aim of this research was to study the axial and radial distributions of the Sauter Mean Diameter (SMD) and velocity vectors in pulsing spray patterns of native and modified tapioca starch solutions. To meet the objective, high speed imaging and Phase Doppler Anemometry (PDA) techniques were employed to characterize the four compositions of the starch-urea-borax complex namely S0, S1, S2 and S3. The unheated solutions exhibited very high viscosities ranging from 2035 to 3030 cP. No jet breakup was seen at any stage of the nozzle operation at an injection pressure of 1-5 bar. However, at 80 °C temperature and 5 bar pressure, the viscosity was reduced to 455 to 638 cP and dense spray patterns emerged from the nozzle obscuring the PDA signals. The axial size distribution revealed a significant decrease in SMD along the spray centreline. The smallest axial SMD (51 to 79 μm) was noticed in S0 spray followed by S1, S2 and S3. Unlikely, the radial SMD in S0 spray did not vary significantly at any stage of the spray injection. This trend was attributed to the continuous growth of the surface wave instabilities on the native starch sheet. However, SMD obtained with S1, S2 and S3 varied appreciably along the radial direction. The mean velocity vector profiles followed the non-Gaussian distribution. The constant vector distributions were seen in the near nozzle regions, where the spray was in the phase of development. In far regions, the velocity vectors were poly-dispersed and a series of ups and downs were seen in the respective radial

  8. Investigation of MM-PBSA rescoring of docking poses.

    PubMed

    Thompson, David C; Humblet, Christine; Joseph-McCarthy, Diane

    2008-05-01

    Target-based virtual screening is increasingly used to generate leads for targets for which high quality three-dimensional (3D) structures are available. To allow large molecular databases to be screened rapidly, a tiered scoring scheme is often employed whereby a simple scoring function is used as a fast filter of the entire database and a more rigorous and time-consuming scoring function is used to rescore the top hits to produce the final list of ranked compounds. Molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) approaches are currently thought to be quite effective at incorporating implicit solvation into the estimation of ligand binding free energies. In this paper, the ability of a high-throughput MM-PBSA rescoring function to discriminate between correct and incorrect docking poses is investigated in detail. Various initial scoring functions are used to generate docked poses for a subset of the CCDC/Astex test set and to dock one set of actives/inactives from the DUD data set. The effectiveness of each of these initial scoring functions is discussed. Overall, the ability of the MM-PBSA rescoring function to (i) regenerate the set of X-ray complexes when docking the bound conformation of the ligand, (ii) regenerate the X-ray complexes when docking conformationally expanded databases for each ligand which include "conformation decoys" of the ligand, and (iii) enrich known actives in a virtual screen for the mineralocorticoid receptor in the presence of "ligand decoys" is assessed. While a pharmacophore-based molecular docking approach, PhDock, is used to carry out the docking, the results are expected to be general to use with any docking method. PMID:18465849

  9. Rotman lens for mm-wavelengths

    NASA Astrophysics Data System (ADS)

    Hall, Leonard T.; Hansen, Hedley J.; Abbott, Derek

    2002-11-01

    The 77 GHz band has been reserved for intelligent cruise control in luxury cars and some public transport services in America and the United Kingdom. The Rotman lens offers a cheap and compact means to extend the single beam systems generally used, to fully functional beam staring arrangements. Rotman lenses have been built for microwave frequencies with limited success. The flexibility of microstrip transmission lines and the advent of fast accurate simulation packages allow practical Rotman lenses to be designed at mm-wavelengths. This paper discusses the limitations of the conventional design approach and predicts the performance of a new Rotman lens designed at 77 GHz.

  10. Plant Habitat (PH)

    NASA Technical Reports Server (NTRS)

    Onate, Bryan

    2016-01-01

    The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

  11. Prediction of Stereochemistry using Q2MM.

    PubMed

    Hansen, Eric; Rosales, Anthony R; Tutkowski, Brandon; Norrby, Per-Ola; Wiest, Olaf

    2016-05-17

    The standard method of screening ligands for selectivity in asymmetric, transition metal-catalyzed reactions requires experimental testing of hundreds of ligands from ligand libraries. This "trial and error" process is costly in terms of time as well as resources and, in general, is scientifically and intellectually unsatisfying as it reveals little about the underlying mechanism behind the selectivity. The accurate computational prediction of stereoselectivity in enantioselective catalysis requires adequate conformational sampling of the selectivity-determining transition state but has to be fast enough to compete with experimental screening techniques to be useful for the synthetic chemist. Although electronic structure calculations are accurate and general, they are too slow to allow for sampling or fast screening of ligand libraries. The combined requirements can be fulfilled by using appropriately fitted transition state force fields (TSFFs) that represent the transition state as a minimum and allow fast conformational sampling using Monte Carlo. Quantum-guided molecular mechanics (Q2MM) is an automated force field parametrization method that generates accurate, reaction-specific TSFFs by fitting the functional form of an arbitrary force field using only electronic structure calculations by minimization of an objective function. A key feature that distinguishes the Q2MM method from many other automated parametrization procedures is the use of the Hessian matrix in addition to geometric parameters and relative energies. This alleviates the known problems of overfitting of TSFFs. After validation of the TSFF by comparison to electronic structure results for a test set and available experimental data, the stereoselectivity of a reaction can be calculated by summation over the Boltzman-averaged relative energies of the conformations leading to the different stereoisomers. The Q2MM method has been applied successfully to perform virtual ligand screens on a range of

  12. The new 800mm reflecting telescope

    NASA Astrophysics Data System (ADS)

    Teske, Hans-Joachim

    The design and capabilities of the 800-mm Ritchey-Chretien system are described. The optical system of the telescope has an aperture ratio of 1:8; is suitable for photography in a 1.5 deg field with photoplates of 16 x 16 cm; and consists of primary and secondary hyperbolically deformed mirrors. The attachment of the mirrors, position rotator, and offset guider to the tube, which is a truss structure, is examined. The mount for the telescope is an equatorial fork type. The electronic control system is a 16-bit microcomputer system; the functions of the control system are discussed. The 8-m polyester dome of the telescope consists of a supporting steel structure carrying shell elements of glass fiber-reinforced polyester resins. Consideration is given to the auxiliary devices of the telescope.

  13. Prediction of Stereochemistry using Q2MM

    PubMed Central

    2016-01-01

    Conspectus The standard method of screening ligands for selectivity in asymmetric, transition metal-catalyzed reactions requires experimental testing of hundreds of ligands from ligand libraries. This “trial and error” process is costly in terms of time as well as resources and, in general, is scientifically and intellectually unsatisfying as it reveals little about the underlying mechanism behind the selectivity. The accurate computational prediction of stereoselectivity in enantioselective catalysis requires adequate conformational sampling of the selectivity-determining transition state but has to be fast enough to compete with experimental screening techniques to be useful for the synthetic chemist. Although electronic structure calculations are accurate and general, they are too slow to allow for sampling or fast screening of ligand libraries. The combined requirements can be fulfilled by using appropriately fitted transition state force fields (TSFFs) that represent the transition state as a minimum and allow fast conformational sampling using Monte Carlo. Quantum-guided molecular mechanics (Q2MM) is an automated force field parametrization method that generates accurate, reaction-specific TSFFs by fitting the functional form of an arbitrary force field using only electronic structure calculations by minimization of an objective function. A key feature that distinguishes the Q2MM method from many other automated parametrization procedures is the use of the Hessian matrix in addition to geometric parameters and relative energies. This alleviates the known problems of overfitting of TSFFs. After validation of the TSFF by comparison to electronic structure results for a test set and available experimental data, the stereoselectivity of a reaction can be calculated by summation over the Boltzman-averaged relative energies of the conformations leading to the different stereoisomers. The Q2MM method has been applied successfully to perform virtual ligand

  14. mm-wave solid state amplifiers

    NASA Astrophysics Data System (ADS)

    Wolfert, P. H.; Crowley, J. D.; Fank, F. B.

    The development of mm-wave amplifiers using InP Gunn diodes is reviewed including a low-noise eight-stage amplifier for replacement of a Ka-band TWTA and a three-stage amplifier for the 42.5 to 44.5 range with an output power of 100 mW and 20 dB associated gain. A detailed description of a three-stage amplifier for the 54 to 58 GHz range is given with 100 mW output power and 15 dB associated gain, a small signal gain of 30 dB and an N.F. of 15.5 to 16.5 dB. The design of a broad band, low-loss V-band circulator, which was used in the amplifier, is described.

  15. pH optrode

    DOEpatents

    Northrup, M. Allen; Langry, Kevin C.

    1993-01-01

    A process is provided for forming a long-lasting, stable, pH-sensitive dye-acrylamide copolymer useful as a pH-sensitive material for use in an optrode or other device sensitive to pH. An optrode may be made by mechanically attaching the copolymer to a sensing device such as an optical fiber.

  16. pH Basics

    ERIC Educational Resources Information Center

    Lunelli, Bruno; Scagnolari, Francesco

    2009-01-01

    The exposition of the pervasive concept of pH, of its foundations and implementation as a meaningful quantitative measurement, in nonspecialist university texts is often not easy to follow because too many of its theoretical and operative underpinnings are neglected. To help the inquiring student we provide a concise introduction to the depth just…

  17. Ph.D. shortage

    NASA Astrophysics Data System (ADS)

    The late 1990s will see a shortage of Ph.D. graduates, according to the Association of American Universities, Washington, D.C. AAU's new comprehensive study, “The Ph.D. Shortage: The Federal Role,” reports that competition for new Ph.D.s is already intense and can only intensify because demand is greater than supply in both academic and nonacademic markets.Doctoral education plays an increasingly important role in U.S. research and development programs. Students have a pivotal part in doing research and enriching it with new ideas. The AAU report says that graduate students are “major determinants of the creativity and productivity of U.S. academic research, the source of more than 50% of the nation's basic research.’ The market for doctoral education extends beyond the university. In 1985, about 43% of all Ph.D.s employed in this country were working outside higher education; the demand for doctorate recipients in nonacademic sectors continues to grow.

  18. Low-Friction Minilaparoscopy Outperforms Regular 5-mm and 3-mm Instruments for Precise Tasks

    PubMed Central

    Firme, Wood A.; Lima, Diego L.; de Paula Lopes, Vladmir Goldstein; Montandon, Isabelle D.; Filho, Flavio Santos; Shadduck, Phillip P.

    2015-01-01

    Background and Objectives: Therapeutic laparoscopy was incorporated into surgical practice more than 25 y ago. Several modifications have since been developed to further minimize surgical trauma and improve results. Minilaparoscopy, performed with 2- to 3-mm instruments was introduced in the mid 1990s but failed to attain mainstream use, mostly because of the limitations of the early devices. Buoyed by a renewed interest, new generations of mini instruments are being developed with improved functionality and durability. This study is an objective evaluation of a new set of mini instruments with a novel low-friction design. Method: Twenty-two medical students and 22 surgical residents served as study participants. Three designs of laparoscopic instruments were evaluated: conventional 5 mm, traditional 3 mm, and low-friction 3 mm. The instruments were evaluated with a standard surgical simulator, emulating 4 exercises of various complexities, testing grasping, precise 2-handed movements, and suturing. The metric measured was time to task completion, with 5 replicates for every combination of instrument–exercise–participant. Results: For all 4 tasks, the instrument design that performed the best was the same in both the medical student and surgical resident groups. For the gross-grasping task, the 5-mm conventional instruments performed best, followed by the low-friction mini instruments. For the 3 more complex and precise tasks, the low-friction mini instruments outperformed both of the other instrument designs. Conclusion: In standard surgical simulator exercises, low-friction minilaparoscopic instruments outperformed both conventional 3- and 5-mm laparoscopic instruments for precise tasks. PMID:26390530

  19. A comparison of 9-inch, 70mm, and 35mm cameras

    NASA Technical Reports Server (NTRS)

    Clegg, R. H.; Scherz, J. P.

    1975-01-01

    Successful aerial photography depends on aerial cameras that provide acceptable photographs within the cost restrictions of the job. For topographic mapping where ultimate accuracy is required, only large-format mapping cameras will suffice. For mapping environmental patterns of vegetation, soils, or water pollution, 9-inch cameras often exceed accuracy and cost requirements, and small formats may be an overall better choice. In choosing the best camera for environmental mapping, relative capabilities and costs must be understood. This study compares resolution, photo interpretation potential, metric accuracy, and cost of 9-inch, 70 mm, and 35 mm cameras for obtaining simultaneous color and color-infrared photography for environmental mapping purposes.

  20. 17-4 PH and 15-5 PH

    NASA Technical Reports Server (NTRS)

    Johnson, Howard T.

    1995-01-01

    17-4 PH and 15-5 PH are extremely useful and versatile precipitation-hardening stainless steels. Armco 17-4 PH is well suited for the magnetic particle inspection requirements of Aerospace Material Specification. Armco 15-5 PH and 17-4 PH are produced in billet, plate, bar, and wire. Also, 15-5 PH is able to meet the stringent mechanical properties required in the aerospace and nuclear industries. Both products are easy to heat treat and machine, making them very useful in many applications.

  1. Planetary brightness temperature measurements at 8.6 mm and 3.1 mm wavelengths.

    NASA Technical Reports Server (NTRS)

    Ulich, B. L.; Cogdell, J. R.; Davis, J. H.

    1973-01-01

    New measurements of the sun, moon, Mercury, Venus, Mars, Jupiter, and Saturn at 3.1- and 8.6-mm wavelengths are given. The temperatures reported for the planets at 3.1-mm wavelength are higher than previous measurements in this wavelength range and change the interpretation of some planetary spectra. For Mercury, it is found that the mean brightness temperature is independent of wavelength and that a temperature-dependent thermal conductivity is not required to match the observations. In the case of Mars, the spectrum is shown to rise in the millimeter region, as simple models predict. For Jupiter, the need to recalculate the spectrum with recent models is demonstrated. The flux density scale proposed by Dent (1972) has been revised according to a more accurate determination of the millimeter brightness temperature of Jupiter.

  2. System performance advances of 18-mm and 16-mm subminiature image intensifier sensors

    NASA Astrophysics Data System (ADS)

    Thomas, Nils I.

    2000-11-01

    Night vision system design has been centered aroudn the An/AVS-6 and AN/PVS-7 night vision goggle systems for the past 20 years. Goggle performance has improved during this time through increased performance of the image intensifier sensor, primarily the Omni IV sensor from ITT Industries Night Vision. Most of this improvement has been at the optimal light level (1E-3 fc scene illumination). Recent advances in image sensor performance from the filmless Generation (Gen) IV sensors has increased the low light level performance of night vision devices from 0.3 cy/mr to 0.7 cy/mr. In addition, sensor packaging design requirements have forced night vision sensor manufactures to design light weight, small volume sensors. ITT recently has designed such a sensor in a 16-mm format. This sensor if 50% lighter, up to 50% shorter, and has design features that simplify the objective lens design. New night vision goggles have been, and are being, designed which reduce the perceived head-supported weight. This paper presents signal-to-noise ratio, halo, and other film-less sensor data and similar 16-mm subminiature sensor data. The resulting system performance data will be described. Finally, the system design improvements and relationships with the subminiature 16-mm subminiature sensor will be given.

  3. Urine pH test

    MedlinePlus

    A urine pH test measures the level of acid in urine. ... pH - urine ... meat products, or cheese can decrease your urine pH. ... to check for changes in your urine acid levels. It may be done to ... more effective when urine is acidic or non-acidic (alkaline).

  4. The LLAMA 12 m mm/sub-mm radiotelescope in the Andes

    NASA Astrophysics Data System (ADS)

    Lepine, Jacques; Edemundo Arnal, Marcelo; de Graauw, Thijs; Abraham, Zulema; Gimenez de Castro, Guillermo; de Gouveia Dal Pino, Elisabete; Morras, Ricardo; Larrarte, Juan; Viramontes, José; Finger, Ricardo; Kooi, Jacob; Reeves, Rodrigo; Beaklini, Pedro

    2015-08-01

    LLAMA (Large Latin American Millimetric Array) is a joint Argentinean-Brazilian project of a 12m mm/sub-mm radio telescope similar to the APEX antenna, to be installed at a site at 4800 m altitude near San Antonio de Los Cobres in the Salta Province in Argentine, at 150 km from ALMA. The scientific cases for single dish and VLBI observations include black holes and accretion disks, the molecular evolution of interstellar clouds, the structure of the Galaxy, the formation of galaxies, and much more. The antenna was ordered to the company Vertex Antennentechnik in June 2014, and the construction is progressing quickly; it will be installed at the site in 2016. The radio telescope will be equipped with up to six receivers covering bands similar to those of ALMA. Cryostats with room for 3 cartridges, constructed by NAOJ (Tokyo,Japan), will be installed in each of the two Nasmyth cabins. Among the first receivers we will have an ALMA band 9 provided by NOVA (Groningen, Holland) and a band 5 from the Chalmers University (Sweden). Other receivers are still being discussed at the time of submission of this abstract,At high frequencies, VLBI observations at high frequencies could be made with ALMA, APEX and ASTE, and Northern radiotelescopes. In this way, LLAMA will be a seed for a Latin-American VLBI network.

  5. Teaching Evolutionary Mechanisms: Genetic Drift and M&M's.

    ERIC Educational Resources Information Center

    Staub, Nancy L.

    2002-01-01

    Describes a classroom activity that teaches the mechanism of genetic drift to undergraduates. Illustrates a number of concepts that are critical in developing evolution literacy by sampling M&M milk chocolate candies. (MM)

  6. Sporadic Creutzfeldt-Jakob Disease MM1+2C and MM1 are Identical in Transmission Properties.

    PubMed

    Kobayashi, Atsushi; Matsuura, Yuichi; Iwaki, Toru; Iwasaki, Yasushi; Yoshida, Mari; Takahashi, Hitoshi; Murayama, Shigeo; Takao, Masaki; Kato, Shinsuke; Yamada, Masahito; Mohri, Shirou; Kitamoto, Tetsuyuki

    2016-01-01

    The genotype (methionine, M or valine, V) at polymorphic codon 129 of the PRNP gene and the type (1 or 2) of abnormal prion protein in the brain are the major determinants of the clinicopathological features of sporadic Creutzfeldt-Jakob disease (CJD), thus providing molecular basis for classification of sporadic CJD, that is, MM1, MM2, MV1, MV2, VV1 or VV2. In addition to these "pure" cases, "mixed" cases presenting mixed neuropathological and biochemical features have also been recognized. The most frequently observed mixed form is the co-occurrence of MM1 and MM2, namely MM1+2. However, it has remained elusive whether MM1+2 could be a causative origin of dura mater graft-associated CJD (dCJD), one of the largest subgroups of iatrogenic CJD. To test this possibility, we performed transmission experiments of MM1+2 prions and a systematic neuropathological examination of dCJD patients in the present study. The transmission properties of the MM1+2 prions were identical to those of MM1 prions because MM2 prions lacked transmissibility. In addition, the neuropathological characteristics of MM2 were totally absent in dCJD patients examined. These results suggest that MM1+2 can be a causative origin of dCJD and causes neuropathological phenotype similar to that of MM1. PMID:25851836

  7. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and Natural Gas Liquids 1 2 MM Table MM-1 to Subpart MM of Part 98 Protection of Environment... Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric tons/bbl... Natural Gas Liquids Aviation Gasoline 0.1120 85.00 0.3490 Special Naphthas 0.1222 84.76 0.3798...

  8. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and Natural Gas Liquids 1 2 MM Table MM-1 to Subpart MM of Part 98 Protection of Environment... Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric tons/bbl... Natural Gas Liquids Aviation Gasoline 0.1120 85.00 0.3490 Special Naphthas 0.1222 84.76 0.3798...

  9. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and Natural Gas Liquids 1 2 MM Table MM-1 to Subpart MM of Part 98 Protection of Environment... Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric tons/bbl... Natural Gas Liquids Aviation Gasoline 0.1120 85.00 0.3490 Special Naphthas 0.1222 84.76 0.3798...

  10. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and Natural Gas Liquids 1 2 MM Table MM-1 to Subpart MM of Part 98 Protection of Environment... Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric tons/bbl... Natural Gas Liquids Aviation Gasoline 0.1120 85.00 0.3490 Special Naphthas 0.1222 84.76 0.3798...

  11. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  12. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  13. 40 CFR Table Mm-2 to Subpart Mm of... - Default Factors for Biomass-Based Fuels and Biomass

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Factors for Biomass-Based Fuels and Biomass MM Table MM-2 to Subpart MM of Part 98 Protection of Environment ENVIRONMENTAL... Biomass-Based Fuels and Biomass Biomass-based fuel and biomass Column A:Density (metric tons/bbl) Column...

  14. A λ = 1.3 mm and 2 mm molecular line survey towards M 82

    NASA Astrophysics Data System (ADS)

    Aladro, R.; Martín, S.; Martín-Pintado, J.; Mauersberger, R.; Henkel, C.; Ocaña Flaquer, B.; Amo-Baladrón, M. A.

    2011-11-01

    Aims: We study the chemical complexity towards the central parts of the starburst galaxy M 82, and investigate the role of certain molecules as tracers of the physical processes in the galaxy circumnuclear region. Methods: We carried out a spectral line survey with the IRAM-30 m telescope towards the northeastern molecular lobe of M 82. It covers the frequency range between 129.8 GHz and 175.0 GHz in the 2 mm atmospheric window, and between 241.0 GHz and 260.0 GHz in the 1.3 mm atmospheric window. Results: Sixty-nine spectral features corresponding to 18 different molecular species are identified. In addition, three hydrogen recombination lines are detected. The species NO, H2S, H2CS, NH2CN, and CH3CN are detected for the first time in this galaxy. Assuming local thermodynamic equilibrium, we determine the column densities of all the detected molecules. We also calculate upper limits to the column densities of fourteen other important, but undetected, molecules, such as SiO, HNCO, or OCS. We compare the chemical composition of the two starburst galaxies M 82 and NGC 253. This comparison enables us to establish the chemical differences between the products of the strong photon-dominated regions driving the heating in M 82, and the large-scale shocks that influence the properties of the molecular clouds in the nucleus of NGC 253. Conclusions: Overall, both sources have different chemical compositions. Some key molecules highlight the different physical processes dominating both central regions. Examples include CH3CCH, c-C3H2, or CO+, the abundances of which are clearly higher in M 82 than in NGC 253, pointing at photodissociating regions. On the other hand, species such as CH2NH, NS, SiO, and HOCO+ have abundances of up to one order of magnitude higher in NGC 253 than in M 82. Appendix is available in electronic form at http://www.aanda.org

  15. A λ 3 mm and 1 mm line survey toward the yellow hypergiant IRC +10420⋆

    PubMed Central

    Quintana-Lacaci, G.; Agúndez, M.; Cernicharo, J.; Bujarrabal, V.; Sánchez Contreras, C.; Castro-Carrizo, A.; Alcolea, J.

    2016-01-01

    Aims Our knowledge of the chemical properties of the circumstellar ejecta of the most massive evolved stars is particularly poor. We aim to study the chemical characteristics of the prototypical yellow hypergiant star, IRC +10420. For this purpose, we obtained full line surveys at 1 and 3 mm atmospheric windows. Methods We have identified 106 molecular emission lines from 22 molecular species. Approximately half of the molecules detected are N-bearing species, in particular HCN, HNC, CN, NO, NS, PN, and N2H+. We used rotational diagrams to derive the density and rotational temperature of the different molecular species detected. We introduced an iterative method that allows us to take moderate line opacities into account. Results We have found that IRC +10420 presents high abundances of the N-bearing molecules compared with O-rich evolved stars. This result supports the presence of a N-rich chemistry, expected for massive stars. Our analysis also suggests a decrease of the 12C/13C ratio from ≳ 7 to ~ 3.7 in the last 3800 years, which can be directly related to the nitrogen enrichment observed. In addition, we found that SiO emission presents a significant intensity decrease for high-J lines when compared with older observations. Radiative transfer modeling shows that this variation can be explained by a decrease in the infrared (IR) flux of the dust. The origin of this decrease might be an expansion of the dust shell or a lower stellar temperature due to the pulsation of the star. PMID:27458319

  16. The pH Game.

    ERIC Educational Resources Information Center

    Chemecology, 1996

    1996-01-01

    Describes a game that can be used to teach students about the acidity of liquids and substances around their school and enable them to understand what pH levels tell us about the environment. Students collect samples and measure the pH of water, soil, plants, and other natural material. (DDR)

  17. Is smaller better? Comparison of 3-mm and 5-mm leaf size for stereotactic radiosurgery: A dosimetric study

    SciTech Connect

    Chern, Shyh-shi . E-mail: Richard.Chern@hci.utah.edu; Leavitt, Dennis D.; Jensen, Randy L.; Shrieve, Dennis C.

    2006-11-15

    Purpose: To perform a dosimetric comparison of a minimal 3-mm leaf width multileaf collimator (MLC) and a minimal 5-mm MLC in dynamic conformal arc stereotactic radiosurgery for treatment of intracranial lesions. Methods and Materials: The treatment plans of 23 patients previously treated for intracranial lesions in our institution were redone using the BrainSCAN, version 5.3, stereotactic radiosurgery treatment planning system (BrainLAB). For each case, two dynamic conformal arc plans were generated: one using a minimal 3-mm micro-MLC (BrainLAB, Novalis) and one using a minimal 5-mm MLC (Varian Millennium). All arc parameters were the same in each of the two plans, except for the collimator angle settings. The collimator angle settings were optimized for each arc in each plan. A peritumoral rind structure (1 cm) was created to evaluate normal tissue sparing immediately adjacent to the target volume. Conformity indexes (CIs) were calculated for each plan. The dependence of normal tissue sparing and target conformity on target volume (TV) was determined. Results: The TV was 0.14-36.32 cm{sup 3} (median, 5.90). The CI was 1.22-2.60 (median, 1.51) for the 3-mm micro-MLC and 1.23-2.69 (median, 1.60) for the 5-mm MLC. Despite this small difference, it was a statistically significant increase (p < 0.0001) for the 5-mm MLC compared with the 3-mm micro-MLC. Improved normal tissue sparing was demonstrated using the 3-mm micro-MLC compared with the 5-mm MLC by examining the peritumoral rind volumes (PRVs) receiving 50% (PRV{sub 5}), 80% (PRV{sub 8}), and 90% (PRV{sub 9}) of the prescription dose. The reduction in the PRV{sub 5}, PRV{sub 8}, and PRV{sub 9} for the 3-mm micro-MLC compared with the 5-mm MLC was 13.5%, 12.9%, and 11.5%, respectively. The CI decreased with a larger TV, as did the difference in the CIs between the 3-mm micro-MLC and 5-mm MLC. A reduction in the PRV increased with larger TVs. Conclusion: The 3-mm micro-MLC provided better target conformity and

  18. Index to 8mm Motion Cartridges. Third Edition.

    ERIC Educational Resources Information Center

    University of Southern California, Los Angeles. National Information Center for Educational Media.

    Research at the National Information Center for Educational Media has shown that the 8mm motion cartridge with optical and magnetic sound seems to meet the basic tenets of a prime educational criterion for an educational medium--that it be available to the learner at his convenience. This is a bibliographical source for 8mm motion cartridges, and…

  19. Index to 8mm Motion Cartridges. Fourth Edition.

    ERIC Educational Resources Information Center

    University of Southern California, Los Angeles. National Information Center for Educational Media.

    Research at the National Information Center for Educational Media (NICEM) has shown that the 8mm motion cartridge with optical and magnetic sound seems to meet the basic tenets of a prime educational criterion for an educational medium--that it be available to the learner at his convenience. This is a bibliographical source for 8mm motion…

  20. Do Noncontingent Interviewer Mm-hmms Facilitate Interviewee Productivity?

    ERIC Educational Resources Information Center

    Siegman, Aron Wolfe

    1976-01-01

    Two studies investigated the hypothesis that noncontingent interviewer "mm-hmms" facilitate interviewee verbal productivity. Within- and between-subjects comparisons failed to support the hypothesis, although interviewees' ratings indicate that the mm-hmms were perceived as the social reinforcers they were intended to be. (Author)

  1. Thales Angenieux: 42 years of cine 35 mm zoom leadership

    NASA Astrophysics Data System (ADS)

    Debize, Jacques

    2004-02-01

    Since the early years of zoom optics, Angenieux has been involved in cine 8 mm, 16 mm and 35 mm. Among more than twenty different zoom lenses, four of them have been milestones in this field, technical progresses being sanctified by two Oscars in 1964 and 1990. From 1960 to 2002 Angenieux has created first the 4 x 35 LA2, the first four times mechanically compensated zoom lens for cine 35 mm in the world, secondary the 10 x 25 T2, the first ten times mechanically compensated zoom lens for cine 35 mm in the world, then the 10 x 25 HR, the top level of quality for its category and finally the 12 x 24 Optimo with all characteristics and performances greatly increased. This leadership has been reached thanks to computers and in-house softwares but also thanks to new manufacturing processes.

  2. Esophageal pH monitoring

    MedlinePlus

    pH monitoring - esophageal; Esophageal acidity test ... esophagitis You may need to have the following tests if your doctor suspects esophagitis : Barium swallow Esophagogastroduodenoscopy (also called upper GI endoscopy)

  3. PhEDEx Data Service

    NASA Astrophysics Data System (ADS)

    Egeland, Ricky; Wildish, Tony; Huang, Chih-Hao

    2010-04-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the "SiteDB" service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

  4. Voltammetric pH Nanosensor.

    PubMed

    Michalak, Magdalena; Kurel, Malgorzata; Jedraszko, Justyna; Toczydlowska, Diana; Wittstock, Gunther; Opallo, Marcin; Nogala, Wojciech

    2015-12-01

    Nanoscale pH evaluation is a prerequisite for understanding the processes and phenomena occurring at solid-liquid, liquid-liquid, and liquid-gas interfaces, e.g., heterogeneous catalysis, extraction, partitioning, and corrosion. Research on the homogeneous processes within small volumes such as intracellular fluids, microdroplets, and microfluidic chips also requires nanometer scale pH assessment. Due to the opacity of numerous systems, optical methods are useless and, if applicable, require addition of a pH-sensitive dye. Potentiometric probes suffer from many drawbacks such as potential drift and lack of selectivity. Here, we present a voltammetric nanosensor for reliable pH assessment between pH 2 and 12 with high spatial resolution. It consists of a pyrolytic carbon nanoelectrode obtained by chemical vapor deposition (CVD) inside a quartz nanopipette. The carbon is modified by adsorption of syringaldazine from its ethanolic solution. It exhibits a stable quasi-reversible cyclic voltammogram with nearly Nernstian dependency of midpeak potentials (-54 mV/pH). This sensor was applied as a probe for scanning electrochemical microscopy (SECM) in order to map pH over a platinum ultramicroelectrode (UME), generating hydroxide ions (OH(-)) by the oxygen reduction reaction (ORR) at a diffusion-controlled rate in aerated phosphate buffered saline (PBS). The results reveal the alkalization of the electrolyte close to the oxygen reducing electrode, showing the insufficient buffer capacity of PBS to maintain a stable pH at the given conditions. PMID:26516786

  5. Amplitude modulation drive to rectangular-plate linear ultrasonic motors with vibrators dimensions 8 mm x 2.16 mm X 1 mm.

    PubMed

    Ming, Yang; Hanson, Ben; Levesley, Martin C; Walker, Peter G; Watterson, Kevin G

    2006-12-01

    In this paper, to exploit the contribution from not only the stators but also from other parts of miniature ultrasonic motors, an amplitude modulation drive is proposed to drive a miniature linear ultrasonic motor consisting of two rectangular piezoelectric ceramic plates. Using finite-element software, the first longitudinal and second lateral-bending frequencies of the vibrator are shown to be very close when its dimensions are 8 mm x 2.16 mm x 1 mm. So one single frequency power should be able to drive the motor. However, in practice the motor is found to be hard to move with a single frequency power because of its small vibration amplitudes and big frequency difference between its longitudinal and bending resonance, which is induced by the boundary condition variation. To drive the motor effectively, an amplitude modulation drive is used by superimposing two signals with nearly the same frequencies, around the resonant frequency of the vibrators of the linear motor. When the amplitude modulation frequency is close to the resonant frequency of the vibrator's surroundings, experimental results show that the linear motor can move back and forward with a maximum thrust force (over 0.016 N) and a maximum velocity (over 50 mm/s). PMID:17186925

  6. Japanese Science Films; a Descriptive and Evaluative Catalog of: 16mm Motion Pictures, 8mm Cartridges, and Video Tapes.

    ERIC Educational Resources Information Center

    Newren, Edward F., Ed.

    One hundred and eighty Japanese 16mm motion pictures, 8mm cartridges, and video tapes produced and judged appropriate for a variety of audience levels are listed in alphabetical order by title with descriptive and evaluative information. A subject heading list and a subject index to the film titles are included, as well as a sample of the…

  7. Replacing 16 mm film cameras with high definition digital cameras

    SciTech Connect

    Balch, K.S.

    1995-12-31

    For many years 16 mm film cameras have been used in severe environments. These film cameras are used on Hy-G automotive sleds, airborne gun cameras, range tracking and other hazardous environments. The companies and government agencies using these cameras are in need of replacing them with a more cost effective solution. Film-based cameras still produce the best resolving capability, however, film development time, chemical disposal, recurring media cost, and faster digital analysis are factors influencing the desire for a 16 mm film camera replacement. This paper will describe a new camera from Kodak that has been designed to replace 16 mm high speed film cameras.

  8. The 19 mm data recorders similarities and differences

    NASA Technical Reports Server (NTRS)

    Atkinson, Steve

    1992-01-01

    Confusion over the use of non-video 19 mm data recorders is becoming more pronounced as we enter the world of high performance computing. This paper addresses the following: the differences between ID-1, ID-2, MIL-STD-2179 and DD-2; what the proper machine is for various applications; how the machine can be integrated into an environment; and any misconceptions there might be about 19 mm tape recorders. DD-2 and 19 mm instrumentation recorders have missions for which each is well designed. While the differences may appear subtle, understanding the difference between the two is the key to picking the right recorder for a particular application.

  9. Corneal biomechanical properties changes after coaxial 2.2-mm microincision and standard 3.0-mm phacoemulsification

    PubMed Central

    Zhang, Zhe; Yu, Hua; Dong, Hui; Wang, Li; Jia, Ya-Ding; Zhang, Su-Hua

    2016-01-01

    AIM To compare the changes in corneal biomechanics measured by ocular response analyzer (ORA) after 2.2-mm microincision cataract surgery and 3.0-mm standard coaxial phacoemulsification. METHODS The prospective nonrandomized study comprised eyes with cataract that had 2.2-mm coaxial microincision or 3.0-mm standard incision phacoemulsification. The corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc) and Goldmann-correlated intraocular pressure (IOPg) were measured by ORA preoperatively and at 1d, 1-, 2-, 3- and 4-week postoperatively. Results were analyzed and compared between groups. RESULTS In both groups, CH decreased in the immediate postoperative period (P<0.05), returned to the preoperative level at one week (P=0.249) in the 2.2-mm group, and at two weeks in the 3.0-mm group (P=0.264); there was no significant change in CRF values. In 2.2-mm group, mean IOPcc and IOPg increased at 1d postoperatively (both P<0.05), and returned to preoperative level at one week (P=0.491 and P=0.923, respectively). In 3.0-mm group, mean IOPcc and IOPg increased at 1d and 1wk postoperatively (P=0.005 and P=0.029, respectively), and returned to preoperative level at 2wk (P=0.347 and P=0.887, respectively). CONCLUSION Significant differences between preoperative and postoperative corneal biomechanical values were found for CH, IOPcc and IOPg. But the recovery time courses were different between the two groups. The 2.2-mm coaxial microincision cataract surgery group seemed recovery faster compared to the 3.0-mm standard coaxial phacoemulsification group. PMID:26949640

  10. Building 904, oblique view to northeast, 210mm lens Travis ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 904, oblique view to northeast, 210mm lens - Travis Air Force Base, Base Spares Warehouse No. 1, Dixon Avenue & W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  11. Building 909, oblique view to southeast, 135 mm lens. Building ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 909, oblique view to southeast, 135 mm lens. Building 908 at extreme right for context. - Travis Air Force Base, Handling Crew Building, North of W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  12. Building 904, oblique view to southeast, 135 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 904, oblique view to southeast, 135 mm lens. - Travis Air Force Base, Base Spares Warehouse No. 1, Dixon Avenue & W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  13. Building 904, oblique view to northwest, 135 mm lens ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 904, oblique view to northwest, 135 mm lens - Travis Air Force Base, Base Spares Warehouse No. 1, Dixon Avenue & W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  14. Building 1204, oblique view to east, 90 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 1204, oblique view to east, 90 mm lens. - Travis Air Force Base, Squadron Operations & Readiness Crew Facility, W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  15. Building 931, oblique view to southeast, 135 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 931, oblique view to southeast, 135 mm lens. - Travis Air Force Base, Central Battery Charging Building, North of W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  16. Building 1204, oblique view to west, 135 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 1204, oblique view to west, 135 mm lens. - Travis Air Force Base, Squadron Operations & Readiness Crew Facility, W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  17. Building 931, oblique view to northwest, 210 mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 931, oblique view to northwest, 210 mm lens. - Travis Air Force Base, Central Battery Charging Building, North of W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  18. Building 932, oblique view to northwest, 90 mm lens. Building ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Building 932, oblique view to northwest, 90 mm lens. Building 933-935 at extreme left. - Travis Air Force Base, Nuclear Weapons Assembly Plant 5, W Street, Armed Forces Special Weapons Project Q Area, Fairfield, Solano County, CA

  19. OpenMM: A Hardware Independent Framework for Molecular Simulations

    PubMed Central

    Eastman, Peter; Pande, Vijay S.

    2015-01-01

    The wide diversity of computer architectures today requires a new approach to software development. OpenMM is a framework for molecular mechanics simulations, allowing a single program to run efficiently on a variety of hardware platforms. PMID:26146490

  20. 35 mm PHOTOGRAPH TAKEN PRIOR TO DEMOLITION OF STRUCTURE. SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35 mm PHOTOGRAPH TAKEN PRIOR TO DEMOLITION OF STRUCTURE. SOUTH (SIDE) AND EAST (FRONT) ELEVATIONS OF BUILDING. VIEW TO NORTHWEST - Plattsburgh Air Force Base, Gas Station, New York Road, Plattsburgh, Clinton County, NY

  1. The 19 mm date recorders: Similarities and differences

    NASA Technical Reports Server (NTRS)

    Atkinson, Steve

    1991-01-01

    Confusion over the use of non-video 19 mm data recorders is becoming more pronounced in the world of high performance computing. The following issues are addressed: (1) the difference between ID-1, ID-2, MIL-STD-2179, and DD-2; (2) the proper machine for the necessary application; and (3) integrating the machine into an existing environment. Also, an attempt is made to clear up any misconceptions there might be about 19 mm tape recorders.

  2. Monolithic mm-wave ICs for smart weapons

    NASA Astrophysics Data System (ADS)

    Duffield, T. L.

    1988-04-01

    An approach to developing a low-cost mm-wave transceiver with application to a broad range of smart weapons systems is described. The proposed transceiver technology consists of monolithic mm-wave integrated circuits on GaAs substrates. The relevant transceiver configurations, FET material, and electron beam lithography are discussed. The types of devices to which the approach is applicable are addressed, emphasizing the use of three-terminal devices for all active elements.

  3. QM/MM investigations of organic chemistry oriented questions.

    PubMed

    Schmidt, Thomas C; Paasche, Alexander; Grebner, Christoph; Ansorg, Kay; Becker, Johannes; Lee, Wook; Engels, Bernd

    2014-01-01

    About 35 years after its first suggestion, QM/MM became the standard theoretical approach to investigate enzymatic structures and processes. The success is due to the ability of QM/MM to provide an accurate atomistic picture of enzymes and related processes. This picture can even be turned into a movie if nuclei-dynamics is taken into account to describe enzymatic processes. In the field of organic chemistry, QM/MM methods are used to a much lesser extent although almost all relevant processes happen in condensed matter or are influenced by complicated interactions between substrate and catalyst. There is less importance for theoretical organic chemistry since the influence of nonpolar solvents is rather weak and the effect of polar solvents can often be accurately described by continuum approaches. Catalytic processes (homogeneous and heterogeneous) can often be reduced to truncated model systems, which are so small that pure quantum-mechanical approaches can be employed. However, since QM/MM becomes more and more efficient due to the success in software and hardware developments, it is more and more used in theoretical organic chemistry to study effects which result from the molecular nature of the environment. It is shown by many examples discussed in this review that the influence can be tremendous, even for nonpolar reactions. The importance of environmental effects in theoretical spectroscopy was already known. Due to its benefits, QM/MM can be expected to experience ongoing growth for the next decade.In the present chapter we give an overview of QM/MM developments and their importance in theoretical organic chemistry, and review applications which give impressions of the possibilities and the importance of the relevant effects. Since there is already a bunch of excellent reviews dealing with QM/MM, we will discuss fundamental ingredients and developments of QM/MM very briefly with a focus on very recent progress. For the applications we follow a similar

  4. Brain tissue oxygen, carbon dioxide, and pH in neurosurgical patients at risk for ischemia.

    PubMed

    Hoffman, W E; Charbel, F T; Edelman, G

    1996-03-01

    A sensor that measures oxygen pressure (PO2), carbon dioxide pressure (PCO2), and pH was evaluated in brain tissue of patients at risk for ischemia. The sensor is 0.5 mm in diameter and was inserted into cortex tissue in 14 patients undergoing craniotomy for cerebrovascular surgery. A compromised cerebral circulation was identified in 8 of 14 patients by single photon emission computed tomography (SPECT) scan, cerebral angiography, and transient ischemic episodes before surgery. Under baseline conditions with isoflurane anesthesia and normal blood gases, tissue P02 was lower in the eight compromised compared to six noncompromised patients (noncompromised 37 +/- 12 mm Hg, compromised 10 +/- 5 mm Hg; P < 0.05), PCO2 was increased (noncompromised 49 +/- 5 mm Hg, compromised 72 +/- 23 mm Hg; P < 0.05), and pH was decreased (noncompromised 7.16 +/- 0.08, compromised 6.82 +/- 0.21; P < 0.05). Critical tissue values for the identification of ischemia were a P02 of 20 mm Hg, PCO2 of 60 mm Hg, and a pH of 7.0. These results suggest that brain tissue measures of P02, PCO2, and pH provide information on the adequacy of cerebral perfusion in neurosurgical patients. PMID:8623965

  5. Spectral Line Survey toward the Young Massive Protostar NGC 2264 CMM3 in the 4 mm, 3 mm, and 0.8 mm Bands

    NASA Astrophysics Data System (ADS)

    Watanabe, Yoshimasa; Sakai, Nami; López-Sepulcre, Ana; Furuya, Ryuta; Sakai, Takeshi; Hirota, Tomoya; Liu, Sheng-Yuan; Su, Yu-Nung; Yamamoto, Satoshi

    2015-08-01

    Spectral line survey observations are conducted toward the high-mass protostar candidate NGC 2264 CMM3 in the 4, 3, and 0.8 mm bands with the Nobeyama 45 m telescope and the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope. In total, 265 emission lines are detected in the 4 and 3 mm bands, and 74 emission lines in the 0.8 mm band. As a result, 36 molecular species and 30 isotopologues are identified. In addition to the fundamental molecular species, many emission lines of carbon-chain molecules such as HC5N, C4H, CCS, and C3S are detected in the 4 and 3 mm bands. Deuterated molecular species are also detected with relatively strong intensities. On the other hand, emission lines of complex organic molecules such as HCOOCH3 and CH3OCH3 are found to be weak. For the molecules for which multiple transitions are detected, rotation temperatures are derived to be 7-33 K except for CH3OH. Emission lines with high upper-state energies (Eu > 150 K) are detected for CH3OH, indicating the existence of a hot core. In comparison with the chemical composition of the Orion KL, carbon-chain molecules and deuterated molecules are found to be abundant in NGC 2264 CMM3, while sulfur-bearing species and complex organic molecules are deficient. These characteristics indicate the chemical youth of NGC 2264 CMM3 in spite of its location at the center of the cluster forming core, NGC 2264 C.

  6. pH Optrode Instrumentation

    NASA Technical Reports Server (NTRS)

    Tabacco, Mary Beth; Zhou, Quan

    1995-01-01

    pH-sensitive chromophoric reagents immobilized in porous optical fibers. Optoelectronic instrumentation system measures acidity or alkalinity of aqueous nutrient solution. Includes one or more optrodes, which are optical-fiber chemical sensors, in sense, analogous to electrodes but not subject to some of spurious effects distorting readings taken by pH electrodes. Concept of optrodes also described in "Ethylene-Vapor Optrodes" (KSC-11579). pH optrode sensor head, with lead-in and lead-out optical fibers, convenient for monitoring solutions located away from supporting electronic equipment.

  7. Resistance of Streptococcus bovis to acetic acid at low pH: Relationship between intracellular pH and anion accumulation

    SciTech Connect

    Russell, J.B. )

    1991-01-01

    Streptococcus bovis JB1, an acid-tolerant ruminal bacterium, was able to grown at pHs from 6.7 to 4.5, and 100 mM acetate had little effect on growth rate or proton motive force across the cell membrane. When S. bovis was grown in glucose-limited chemostats at pH 5.2, the addition of sodium acetate (as much as 100 mM) had little effect on the production of bacterial protein. At higher concentrations of sodium acetate (100 to 360 mM), production of bacterial protein declined, but this decrease could largely be explained by a shift in fermentation products (acetate, formate, and ethanol production to lactate production) and a decline in ATP production (3 ATP per glucose versus 2 ATP per glucose). Y{sub ATP} (grams of cells per mole at ATP) was not decreased significantly even by high concentrations of acetate. Cultures supplemented with 100 mM sodium acetate took up ({sup 14}C)acetate and ({sup 14}C)benzoate in accordance with the Henderson-Hasselbalch equation and gave similar estimates of intracellular pH. As the extracellular pH declined, S. bovis allowed its intracellular pH to decrease and maintained a relatively constant pH gradient across the cell membrane (0.9 unit). The decrease in intracellular pH prevented S. bovis from accumulating large amounts of acetate anion. On the basis of these results it did not appear that acetate was acting as an uncoupler. The sensitivity of other bacteria to volatile fatty acids at low pH is explained most easily by a high transmembrane pH gradient and anion accumulation.

  8. Resistance of Streptococcus bovis to acetic acid at low pH: relationship between intracellular pH and anion accumulation.

    PubMed Central

    Russell, J B

    1991-01-01

    Streptococcus bovis JB1, an acid-tolerant ruminal bacterium, was able to grow at pHs from 6.7 to 4.5, and 100 mM acetate had little effect on growth rate or proton motive force across the cell membrane. When S. bovis was grown in glucose-limited chemostats at pH 5.2, the addition of sodium acetate (as much as 100 mM) had little effect on the production of bacterial protein. At higher concentrations of sodium acetate (100 to 360 mM), production of bacterial protein declined, but this decrease could largely be explained by a shift in fermentation products (acetate, formate, and ethanol production to lactate production) and a decline in ATP production (3 ATP per glucose versus 2 ATP per glucose). YATP (grams of cells per mole of ATP) was not decreased significantly even by high concentrations of acetate. Cultures supplemented with 100 mM sodium acetate took up [14C]acetate and [14C]benzoate in accordance with the Henderson-Hasselbalch equation and gave similar estimates of intracellular pH. As the extracellular pH declined, S. bovis allowed its intracellular pH to decrease and maintained a relatively constant pH gradient across the cell membrane (0.9 unit). The decrease in intracellular pH prevented S. bovis from accumulating large amounts of acetate anion. On the basis of these results it did not appear that acetate was acting as an uncoupler. The sensitivity of other bacteria to volatile fatty acids at low pH is explained most easily by a high transmembrane pH gradient and anion accumulation. PMID:2036013

  9. QM/MM calculations with deMon2k.

    PubMed

    Salahub, Dennis R; Noskov, Sergei Yu; Lev, Bogdan; Zhang, Rui; Ngo, Van; Goursot, Annick; Calaminici, Patrizia; Köster, Andreas M; Alvarez-Ibarra, Aurelio; Mejía-Rodríguez, Daniel; Řezáč, Jan; Cailliez, Fabien; de la Lande, Aurélien

    2015-01-01

    The density functional code deMon2k employs a fitted density throughout (Auxiliary Density Functional Theory), which offers a great speed advantage without sacrificing necessary accuracy. Powerful Quantum Mechanical/Molecular Mechanical (QM/MM) approaches are reviewed. Following an overview of the basic features of deMon2k that make it efficient while retaining accuracy, three QM/MM implementations are compared and contrasted. In the first, deMon2k is interfaced with the CHARMM MM code (CHARMM-deMon2k); in the second MM is coded directly within the deMon2k software; and in the third the Chemistry in Ruby (Cuby) wrapper is used to drive the calculations. Cuby is also used in the context of constrained-DFT/MM calculations. Each of these implementations is described briefly; pros and cons are discussed and a few recent applications are described briefly. Applications include solvated ions and biomolecules, polyglutamine peptides important in polyQ neurodegenerative diseases, copper monooxygenases and ultra-rapid electron transfer in cryptochromes. PMID:25786164

  10. The same-source parallel MM{sub 5}.

    SciTech Connect

    Michalakes, J.

    1999-08-23

    The set of architectures available to users of the Penn State/NCAR MM5 has been expanded to included distributed-memory parallel computers, providing cost-effective scalable performance and memory capacity for large problem sizes. The same-source approach uses high-level parallel library and source-translation technology for adapting MM5, simplifying maintenance and allowing new physics modules to be incorporated without modification. The approach facilitates maintenance of the DM-parallel option to MM5 as an option within the official version, rather than as a separate stand-alone version. As a result, the DM-parallel option to MM5 (now at Version 3.1) has been a part of six subsequent model releases since MM5 Version 2.8 in March 1998. The same-source approach is applicable to other, similarly constructed codes when there is a need or desire to develop the code for distributed memory parallel machines without impacting the pre-existing source code. The approach is also compatible with pre-existing loop-level multithreading directives so that the code will run in distributed-memory/shared-memory mode on SMP clusters.

  11. CMOS mm-wave transceivers for Gbps wireless communication

    NASA Astrophysics Data System (ADS)

    Baoyong, Chi; Zheng, Song; Lixue, Kuang; Haikun, Jia; Xiangyu, Meng; Zhihua, Wang

    2016-07-01

    The challenges in the design of CMOS millimeter-wave (mm-wave) transceiver for Gbps wireless communication are discussed. To support the Gbps data rate, the link bandwidth of the receiver/transmitter must be wide enough, which puts a lot of pressure on the mm-wave front-end as well as on the baseband circuit. This paper discusses the effects of the limited link bandwidth on the transceiver system performance and overviews the bandwidth expansion techniques for mm-wave amplifiers and IF programmable gain amplifier. Furthermore, dual-mode power amplifier (PA) and self-healing technique are introduced to improve the PA's average efficiency and to deal with the process, voltage, and temperature variation issue, respectively. Several fully-integrated CMOS mm-wave transceivers are also presented to give a short overview on the state-of-the-art mm-wave transceivers. Project supported in part by the National Natural Science Foundation of China (No. 61331003).

  12. The brightness temperature of Mercury at mm-wavelengths

    NASA Astrophysics Data System (ADS)

    Greve, A.; Thum, C.; Moreno, R.; Yan, N.

    2009-02-01

    We present observations of Mercury made with the IRAM 30-m telescope at 3, 2 and 1.3 mm wavelength (90, 150 and 230 GHz) during the years 1985-2005; we derive from these data the disk-averaged brightness temperatures. The observations at 3 mm combined with those by Epstein & Andrew allow a separation of the data into 40° wide longitude intervals and by this an investigation of the disk-averaged brightness temperature with Mercury's longitude. From the new mm-wavelength data, and data taken from the literature, we derive the disk-averaged brightness temperature as a function of wavelength. On Mercury's night side a significant decrease in brightness temperature occurs towards shorter wavelengths. We use the three surface models (A,B,C) discussed by Mitchell & de Pater and calculate for the cool and hot surface region the corrresponding diurnal variation of the disk-averaged brightness temperature at 90 GHz. For the same models we calculate the variation of the disk-averaged brightness temperature with wavelength between 1.3 mm and 37 mm, on Mercury's midnight side and noon side. Although the scatter in the observations is large, there seems to be a marginally better agreement with model B and A.

  13. Urine pH test

    MedlinePlus

    ... J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team. Related MedlinePlus Health Topics Kidney Stones Urinalysis Browse the Encyclopedia A. ...

  14. Making pH Tangible.

    ERIC Educational Resources Information Center

    McIntosh, Elizabeth; Moss, Robert

    1995-01-01

    Presents a laboratory exercise in which students test the pH of different substances, study the effect of a buffer on acidic solutions by comparing the behavior of buffered and unbuffered solutions upon the addition of acid, and compare common over-the-counter antacid remedies. (MKR)

  15. Engineering Strong Interactions Between mm-wave and Optical Photons

    NASA Astrophysics Data System (ADS)

    Stone, Mark; Suleymanzade, Aziza; Estes, Jeremy; Eustice, Scott; Schuster, David; Simon, Jonathan

    2016-05-01

    We propose an atomic interface of Rydberg atoms as a means of engineering effective strong interactions between single mm-wave and optical photons. The atomic sample resides at the intersection of a high-finesse optical cavity and a superconducting mm-wave cavity, where it can coherently interact with photons of both regimes. The use of mm-wave (100 GHz) frequencies allows strong coupling at higher temperatures and with less sensitivity to stray electric fields. A hybrid cryogenic vacuum chamber at 4 Kelvin enables access to superconductivity as well as a UHV environment with optical access necessary for cold atom experiments. Strong interactions between these separate quantum degrees of freedom has important applications in quantum computing as well as simulation of many-body interacting systems.

  16. QM/MM X-ray Refinement of Zinc Metalloenzymes

    PubMed Central

    Li, Xue; Hayik, Seth A.; Merz, Kenneth M.

    2010-01-01

    Zinc metalloenzymes play an important role in biology. However, due to the limitation of molecular force field energy restraints used in X-ray refinement at medium or low resolutions, the precise geometry of the zinc coordination environment can be difficult to distinguish from ambiguous electron density maps. Due to the difficulties involved in defining accurate force fields for metal ions, the QM/MM (Quantum-Mechanical /Molecular-Mechanical) method provides an attractive and more general alternative for the study and refinement of metalloprotein active sites. Herein we present three examples that indicate that QM/MM based refinement yields a superior description of the crystal structure based on R and Rfree values and on the inspection of the zinc coordination environment. It is concluded that QM/MM refinement is a useful general tool for the improvement of the metal coordination sphere in metalloenzyme active sites. PMID:20116858

  17. Laparoscopic 5-mm Trocar Site Herniation and Literature Review

    PubMed Central

    Minikel, Laura; Zaritsky, Eve

    2011-01-01

    Objective: To evaluate the evidence for fascial closure of 5-mm laparoscopic trocar sites. Methods: We conducted electronic database searches of PubMed and the Cochrane Library for articles published between November 2008 and December 2010. We used the keywords trocar hernia, trocar-site hernia, laparoscopic hernia, trocar port-site hernia, laparoscopic port-site hernia. Prospective and retrospective case series, randomized trials, literature reviews, and randomized animal studies of trocar hernias on abdominal wall defects from gynecologic, urologic, and general surgery literature were reviewed. The Cochrane Database was reviewed for pertinent studies. Metaanalysis was not possible due to the significant heterogeneity between studies and lack of randomized trials large enough to assess the incidence of this rare complication. Results: Trocar-site hernias are a rare but known complication of laparoscopic surgery. Trocar size ≥10mm is associated with an increased rate of hernia development. Currently, the accepted gynecologic surgical practice is closure of fascial incisions ≥10mm, while incisions <10mm do not require closure. However, large prospective and retrospective case series reports from general surgery and urology literature support nonclosure of blunt or radially dilating trocars in paramedian sites. Expert opinion and small case reports suggest that in cases of prolonged manipulation of 5-mm trocar sites the surgeon should consider fascial closure, because extension of the initial incision may have occurred. Conclusion: There is no evidence to recommend routine closure of 5-mm trocar incisions; the choice should continue to be left to the discretion of the individual surgeon. PMID:21902958

  18. 450mm wafer patterning with jet and flash imprint lithography

    NASA Astrophysics Data System (ADS)

    Thompson, Ecron; Hellebrekers, Paul; Hofemann, Paul; LaBrake, Dwayne L.; Resnick, Douglas J.; Sreenivasan, S. V.

    2013-09-01

    The next step in the evolution of wafer size is 450mm. Any transition in sizing is an enormous task that must account for fabrication space, environmental health and safety concerns, wafer standards, metrology capability, individual process module development and device integration. For 450mm, an aggressive goal of 2018 has been set, with pilot line operation as early as 2016. To address these goals, consortiums have been formed to establish the infrastructure necessary to the transition, with a focus on the development of both process and metrology tools. Central to any process module development, which includes deposition, etch and chemical mechanical polishing is the lithography tool. In order to address the need for early learning and advance process module development, Molecular Imprints Inc. has provided the industry with the first advanced lithography platform, the Imprio® 450, capable of patterning a full 450mm wafer. The Imprio 450 was accepted by Intel at the end of 2012 and is now being used to support the 450mm wafer process development demands as part of a multi-year wafer services contract to facilitate the semiconductor industry's transition to lower cost 450mm wafer production. The Imprio 450 uses a Jet and Flash Imprint Lithography (J-FILTM) process that employs drop dispensing of UV curable resists to assist high resolution patterning for subsequent dry etch pattern transfer. The technology is actively being used to develop solutions for markets including NAND Flash memory, patterned media for hard disk drives and displays. This paper reviews the recent performance of the J-FIL technology (including overlay, throughput and defectivity), mask development improvements provided by Dai Nippon Printing, and the application of the technology to a 450mm lithography platform.

  19. Absolute brightness temperature measurements at 2.1-mm wavelength

    NASA Technical Reports Server (NTRS)

    Ulich, B. L.

    1974-01-01

    Absolute measurements of the brightness temperatures of the Sun, new Moon, Venus, Mars, Jupiter, Saturn, and Uranus, and of the flux density of DR21 at 2.1-mm wavelength are reported. Relative measurements at 3.5-mm wavelength are also preented which resolve the absolute calibration discrepancy between The University of Texas 16-ft radio telescope and the Aerospace Corporation 15-ft antenna. The use of the bright planets and DR21 as absolute calibration sources at millimeter wavelengths is discussed in the light of recent observations.

  20. Full-mesh optical backplane with standard MM fiber ribbons

    NASA Astrophysics Data System (ADS)

    Ferrario, M.; Coviello, D.; Boffi, P.; Martinelli, M.; Basile, V.; Fassi, I.; Falcucci, M.; Renghini, C.; Scalmati, Paolo

    2016-03-01

    A new optical backplane solution is proposed for high-capacity ICT apparatus. A modular, scalable and full-mesh bandwidth-upgradable optical interconnection between optoelectronic boards is guaranteed thanks to an optimized layout of standard MM 12-fiber ribbons which divides the overall backplane into several independent optical sub-circuits. The novel automated assembly procedure of fiber ribbons inside sub-circuits with a robotic work-cell is described. System validation of the optical backplane performed with commercially available MM 12-fiber transceivers @10Gb/s proved the feasibility of the proposed solution for future optical interconnections with terabit overall capacity.

  1. Novel Processing of 81-mm Cu Shaped Charge Liners

    SciTech Connect

    Schwartz, A; Korzekwa, D

    2002-01-16

    A seven-step procedure was developed for producing shaped charge liner blanks by back extrusion at liquid nitrogen temperatures. Starting with a 38.1-mm diameter, 101.6-mm long cylinder at 77K, three forging steps with a flat-top die are required to produce the solid cone while maintaining low temperature. The solid cone is forged in four individual back extrusions at 77K to produce the rough liner blank. This procedure is capable of being run in batch processes to improve the time efficiency.

  2. Performance evaluation of 4.75-mm NMAS superpave mixture

    NASA Astrophysics Data System (ADS)

    Rahman, Farhana

    A Superpave asphalt mixture with 4.75-mm nominal maximum aggregate size (NMAS) is a promising, low-cost pavement preservation treatment for agencies such as the Kansas Department of Transportation (KDOT). The objective of this research study is to develop an optimized 4.75-mm NMAS Superpave mixture in Kansas. In addition, the study evaluated the residual tack coat application rate for the 4.75-mm NMAS mix overlay. Two, hot-in-place recycling (HIPR) projects in Kansas, on US-160 and K-25, were overlaid with a 15- to 19-mm thick layer of 4.75-mm NMAS Superpave mixture in 2007. The field tack coat application rate was measured during construction. Cores were collected from each test section for Hamburg wheel tracking device (HWTD) and laboratory bond tests performed after construction and after one year in service. Test results showed no significant effect of the tack coat application rate on the rutting performance of rehabilitated pavements. The number of wheel passes to rutting failure observed during the HWTD test was dependent on the aggregate source as well as on in-place density of the cores. Laboratory pull-off tests showed that most cores were fully bonded at the interface of the 4.75-mm NMAS overlay and the HIPR layer, regardless of the tack application rate. The failure mode during pull-off tests at the HMA interface was highly dependent on the aggregate source and mix design of the existing layer material. This study also confirmed that overlay construction with a high tack coat application rate may result in bond failure at the HMA interface. Twelve different 4.75-mm NMAS mix designs were developed using materials from the aforementioned but two binder grades and three different percentages of natural (river) sand. Laboratory performance tests were conducted to assess mixture performance. Results show that rutting and moisture damage potential in the laboratory depend on aggregate type irrespective of binder grade. Anti-stripping agent affects moisture

  3. Simultaneous in vivo pH and temperature mapping using a PARACEST-MRI contrast agent.

    PubMed

    McVicar, Nevin; Li, Alex X; Suchý, Mojmír; Hudson, Robert H E; Menon, Ravi S; Bartha, Robert

    2013-10-01

    Altered tissue temperature and/or pH is a common feature in pathological conditions, where metabolic demand exceeds oxygen supply such as in tumors and following stroke. Therefore, in vivo tissue temperature and pH may become valuable biomarkers for disease detection and the monitoring of disease progression or treatment response in conditions with altered metabolic demand. In this study, pH is measured using the amide protons of a thulium (Tm(3+)) complex with a DOTAM-Glycine-Lysine (ligand: Tm(3+)-DOTAM-Gly-Lys). The pH was uniquely determined from the linewidth of the asymmetry curve of the chemical exchange saturation transfer spectrum, independent of contrast agent concentration, or temperature for a given saturation pulse. pH maps with an inter-pixel standard deviation of less than 0.1 pH units were obtained in 10 mM Tm(3+)-DOTAM-Gly-Lys solutions with pH ranging from 6.0 to 8.0 pH units at 37°C. Temperature maps were simultaneously obtained using the chemical shift of the chemical exchange saturation transfer peak. Temperature and pH maps are demonstrated in the mouse leg (N = 3), where the mean and standard deviation for pH was 7.2 ± 0.2 pH unit and temperature was 37.4 ± 0.5°C. PMID:23165779

  4. IMPLEMENTATION OF AN URBAN CANOPY PARAMETERIZATION IN MM5

    EPA Science Inventory

    The Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5) (Grell et al. 1994) has been modified to include an urban canopy parameterization (UCP) for fine-scale urban simulations (~1-km horizontal grid spacing). The UCP accounts for drag ...

  5. Security architecture of the M&M mobile agent framework

    NASA Astrophysics Data System (ADS)

    Marques, Paulo J.; Santos, Nuno F.; Silva, Luis; Silva, Joao G.

    2001-07-01

    In the Mobile Agent programming model, small threads of execution migrate from machine to machine, performing their operations locally. For being able to deploy such a model into real world applications, security is a vital concern. In the M&M project we have developed a system that departures from the traditional platform-based execution model for mobile agents. In M&M there are no agent platforms. Instead there is a component framework that allows the applications to become able of sending and receiving agents by themselves in a straightforward manner. In this paper we examine the security mechanisms available in M&M, and how integration with existing applications is done. One difficult aspect of this work is that all the features must work with the security mechanisms that already exist on the applications. This is so because the components are integrated from within into the applications, which already have security mechanisms in place. Currently, M&M provides features like fine-grain security permissions, encryption of agents and data, certificate distribution using LDAP and cryptographic primitives for agents. For validating the approach and solutions found, we have integrated the framework into several off-the-shelf web servers, having the security mechanisms running, with no problems.

  6. Guide to Free-Loan Sports Films (16mm).

    ERIC Educational Resources Information Center

    1974

    This catalog provides information on free 16 mm films dealing with a wide variety of individual and team sports, such as football, golf, water sports, snow sports, racing, and baseball, as well as on general sports competition and safety. Unless otherwise noted, the films are in color and with sound. Titles are listed alphabetically under their…

  7. Guide to Films (16 mm) About Negroes. First Edition.

    ERIC Educational Resources Information Center

    1970

    Over 740 films (16 mm.) concerning the lives, culture, history, and problems of Black people in the United States and in Africa are listed alphabetically by title in this guide. Each entry includes the running time, a synopsis of the film's content, and a source code and tells whether the film is in black-and-white or in color. The guide includes…

  8. Herschel FIR Spectroscopic Observations of L1448-MM

    NASA Astrophysics Data System (ADS)

    Lee, Jinhee; Lee, J.; DIGIT Team

    2012-01-01

    We present the FIR (continuum and line) maps and spectra of L1448-MM at 55 to 210 micron observed with the range scan mode of PACS on the Herschel Space Observatory, as part of the DIGIT key program. L1448-MM was previously known as an embedded Class 0 and prominent outflow source, and a secondary YSO was claimed by the Spitzer images and confirmed by submm interferometric observations. The PACS detected various CO, OH, H2O, and OI lines. The PACS line and continuum maps show that the emission at shorter wavelengths peaks at the central spatial pixel (the primary YSO position) although the line emission of low energy levels distributes along the outflow direction. According to our excitation analysis, the CO gas has two temperature components (warm and hot) that are tentatively attributed to PDR and shock, respectively. However, the H2O gas with the rotational temperature of 200 K seems to trace the shock. Interestingly, the relative strength of OH transitions suggests the IR pumping process dominates in L1448-MM. The gas along the outflow cavities in L1448-MM seems to be heated mainly by shock and UV photons, and relative line luminosities indicate that H2O and CO are the main coolants of this gas, although cooling by OI and OH cannot be ignored.

  9. RF and mm-Wave Photonics at Sandia National Laboratories

    SciTech Connect

    Vawter, G.A.; Sullivan, C.

    1999-07-08

    RF and mm-wave photonic devices and circuits have been developed at Sandia National Laboratories for applications ranging from RF optical data links to optical generation of mm-wave frequencies. This talk will explore recent high-speed photonics technology developments at Sandia including: (1) A monolithic optical integrated circuit for all-optical generation of mm-waves. Using integrated mode-locked diode lasers, amplifiers, and detectors, frequencies between 30 GHz and 90 GHz are generated by a single monolithic (Al,Ga)As optical circuit less than 2mm in its largest dimension. (2) Development of polarization-maintaining, low-insertion-loss, low v-pi, Mach-Zehnder interferometer (MZI) modulators with DC-to-potentially-K-band modulation bandwidth. New low-loss polarization-maintaining waveguide designs using binary alloys have been shown to reduce polarization crosstalk in undoped (Al,Ga)As waveguides, yielding high extinction ratio (>40dB) and low on-chip loss (<6dB) in Mach-Zehnder interferometers. RF drive voltage is reduced through use of 45rnrn-active length devices with modulator sensitivity, v-pi, less than 3V.

  10. Guide to Films (16 mm) About Ecology, Adaptation and Pollution.

    ERIC Educational Resources Information Center

    1971

    Synopses of 350 films (16 mm.) on ecology, adaptation of plants and animals to their environment, and environmental pollution are listed alphabetically by title in this guide. It specifies whether the film is black-and-white or color, its running time, and its source. An abbreviated subject index and a directory of sources are also provided. The…

  11. Index to 8mm Motion Cartridges. Second Edition.

    ERIC Educational Resources Information Center

    University of Southern California, Los Angeles. National Information Center for Educational Media.

    This index to 8mm motion cartridges contains almost 10,000 entries, arranged alphabetically both by individual title and by series title in the main section of the book. Individual title entries include title with subtitle, size and physical description, length of film, stock or color code, description of contents, series title reference when…

  12. Advisory List of Instructional Media--16MM Films.

    ERIC Educational Resources Information Center

    North Carolina State Dept. of Public Instruction, Raleigh. Div. of Educational Media.

    These two advisory lists include information on 16mm films appropriate for the K-12 instructional program. In both bibliographies films are listed in the following categories: communication skills; guidance; health, physical education, safety, and sports; science; and social studies. The list for the 1982-1983 school year also includes categories…

  13. Operation and Maintenance of the 16mm Sound Film Projector.

    ERIC Educational Resources Information Center

    Rampino, Tony; Schexnaydre, Linda

    This manual presents information in seven sections: (1) parts of a 16mm film projector--film transport, threading, control, film projection, and sound system, and film projection correction devices, (2) threading procedures, (3) projection screens, (4) typical operating problems, (5) minor maintenance and repair techniques, (6) hints for the film…

  14. Mineralogic Model (MM3.0) Analysis Model Report

    SciTech Connect

    C. Lum

    2002-02-12

    The purpose of this report is to document the Mineralogic Model (MM), Version 3.0 (MM3.0) with regard to data input, modeling methods, assumptions, uncertainties, limitations and validation of the model results, qualification status of the model, and the differences between Version 3.0 and previous versions. A three-dimensional (3-D) Mineralogic Model was developed for Yucca Mountain to support the analyses of hydrologic properties, radionuclide transport, mineral health hazards, repository performance, and repository design. Version 3.0 of the MM was developed from mineralogic data obtained from borehole samples. It consists of matrix mineral abundances as a function of x (easting), y (northing), and z (elevation), referenced to the stratigraphic framework defined in Version 3.1 of the Geologic Framework Model (GFM). The MM was developed specifically for incorporation into the 3-D Integrated Site Model (ISM). The MM enables project personnel to obtain calculated mineral abundances at any position, within any region, or within any stratigraphic unit in the model area. The significance of the MM for key aspects of site characterization and performance assessment is explained in the following subsections. This work was conducted in accordance with the Development Plan for the MM (CRWMS M&O 2000). The planning document for this Rev. 00, ICN 02 of this AMR is Technical Work Plan, TWP-NBS-GS-000003, Technical Work Plan for the Integrated Site Model, Process Model Report, Revision 01 (CRWMS M&O 2000). The purpose of this ICN is to record changes in the classification of input status by the resolution of the use of TBV software and data in this report. Constraints and limitations of the MM are discussed in the appropriate sections that follow. The MM is one component of the ISM, which has been developed to provide a consistent volumetric portrayal of the rock layers, rock properties, and mineralogy of the Yucca Mountain site. The ISM consists of three components: (1

  15. MM 55266 and MM 55268, glycopeptide antibiotics produced by a new strain of Amycolatopsis. Isolation, purification and structure determination.

    PubMed

    Box, S J; Coates, N J; Davis, C J; Gilpin, M L; Houge-Frydrych, C S; Milner, P H

    1991-08-01

    Two novel glycopeptide antibiotics MM 55266 and MM 55268 containing fatty acid acyl functions, and of molecular formula C86H89N8O35Cl5 and C87H91N8O35Cl5, respectively, have been isolated and identified from a complex produced by Amycolatopsis sp. NCIB 40089. Fermentation conditions for their production, and methods for their isolation are described. Structures have been deduced by use of COSY and NOE NMR techniques and supported by chemical degradation studies. Both glycopeptides possessed good antibacterial activity against Gram-positive organisms. PMID:1917694

  16. Charpy impact test results on five materials and NIST verification specimens using instrumented 2-mm and 8-mm strikers

    SciTech Connect

    Nanstad, R.K.; Sokolov, M.A.

    1995-04-01

    The Heavy-Section Steel Irradiation Program at Oak Ridge National Laboratory is involved in two cooperative projects, with international participants, both of which involve Charpy V-notch impact tests with instrumented strikers of 2mm and 8mm radii. Two heats of A 533 grade B class I pressure vessel steel and a low upper-shelf (LUS) submerged-arc (SA) weld were tested on the same Charpy machine, while one heat of a Russian Cr-Mo-V forging steel and a high upper-shelf (HUS) SA weld were tested on two different machines. The number of replicate tests at any one temperature ranged from 2 to 46 specimens. Prior to testing with each striker, verification specimens at the low, high, and super high energy levels from the National Institute of Standards and Technology (NIST) were tested. In the two series of verification tests, the tests with the 2mm striker met the requirements at the low and high energy levels but not at the super high energy. For one plate, the 2mm striker showed somewhat higher average absorbed energies than those for the 8-mm striker at all three test temperatures. For the second plate and the LUS weld, however, the 2mm striker showed somewhat lower energies at both test temperatures. For the Russian forging steel and the HUS weld, tests were conducted over a range of temperatures with tests at one laboratory using the 8mm striker and tests at a second laboratory using the 2mm striker. Lateral expansion was measured for all specimens and the results are compared with the absorbed energy results. The overall results showed generally good agreement (within one standard deviation) in energy measurements by the two strikers. Load-time traces from the instrumented strikers were also compared and used to estimate shear fracture percentage. Four different formulas from the European Structural Integrity Society draft standard for instrumented Charpy test are compared and a new formula is proposed for estimation of percent shear from the force-time trace.

  17. Rodent models of pulmonary hypertension: harmonisation with the world health organisation's categorisation of human PH.

    PubMed

    Ryan, J; Bloch, K; Archer, S L

    2011-08-01

    The WHO classification of pulmonary hypertension (PH) recognises five distinct groups, all sharing a mean, resting, pulmonary artery pressure (PAP) > 25 mmHg. The aetiology of PH varies by group (1-pulmonary vascular disease, 2-high left heart filling pressures, 3-hypoxia, 4-unresolved pulmonary embolism and 5-miscellaneous). Inclusion in a group reflects shared histological, haemodynamic and pathophysiological features and has therapeutic implications. Advantages of using rodent models to understand the pathophysiology of human PH and to test experimental therapies include the economy, safety and mechanistic certainty they provide. As rodent models are meant to reflect human PH, they should be categorised by a parallel PH classification and limitations in achieving this ideal recognised. Challenges with rodent models include: accurate phenotypic characterisation (haemodynamics, histology and imaging), species and strain variations in the natural history of PH, and poor fidelity to the relevant human PH group. Rat models of group 1 PH include: monocrotaline (± pneumonectomy), chronic hypoxia + SU-5416 (a VEGF receptor inhibitor) and the fawn-hooded rat (FHR). Mouse models of group 1 PH include: transgenic mice overexpressing the serotonin transporter or dominant-negative mutants of bone morphogenetic protein receptor-2. Group 1 PH is also created by infecting S100A4/Mts1 mice with γ-herpesvirus. The histological features of group 1 PH, but not PH itself, are induced by exposure to Schistosoma mansoni or Stachybotrys chartarum. Group 3 PH is modelled by exposure of rats or mice to chronic hypoxia. Rodent models of groups 2, 4 and 5 PH are needed. Comprehensive haemodynamic, histological and molecular phenotyping, coupled with categorisation into WHO PH groups, enhances the utility of rodent models. PMID:21736677

  18. The Methods Behind PH WINS

    PubMed Central

    Leider, Jonathon P.; Bharthapudi, Kiran; Pineau, Vicki; Liu, Lin; Harper, Elizabeth

    2015-01-01

    The Public Health Workforce Interests and Needs Survey (PH WINS) has yielded the first-ever nationally representative sample of state health agency central office employees. The survey represents a step forward in rigorous, systematic data collection to inform the public health workforce development agenda in the United States. PH WINS is a Web-based survey and was developed with guidance from a panel of public health workforce experts including practitioners and researchers. It draws heavily from existing and validated items and focuses on 4 main areas: workforce perceptions about training needs, workplace environment and job satisfaction, perceptions about national trends, and demographics. This article outlines the conceptualization, development, and implementation of PH WINS, as well as considerations and limitations. It also describes the creation of 2 new data sets that will be available in public use for public health officials and researchers—a nationally representative data set for permanently employed state health agency central office employees comprising over 10 000 responses, and a pilot data set with approximately 12 000 local and regional health department staff responses. PMID:26422490

  19. The Methods Behind PH WINS.

    PubMed

    Leider, Jonathon P; Bharthapudi, Kiran; Pineau, Vicki; Liu, Lin; Harper, Elizabeth

    2015-01-01

    The Public Health Workforce Interests and Needs Survey (PH WINS) has yielded the first-ever nationally representative sample of state health agency central office employees. The survey represents a step forward in rigorous, systematic data collection to inform the public health workforce development agenda in the United States. PH WINS is a Web-based survey and was developed with guidance from a panel of public health workforce experts including practitioners and researchers. It draws heavily from existing and validated items and focuses on 4 main areas: workforce perceptions about training needs, workplace environment and job satisfaction, perceptions about national trends, and demographics. This article outlines the conceptualization, development, and implementation of PH WINS, as well as considerations and limitations. It also describes the creation of 2 new data sets that will be available in public use for public health officials and researchers--a nationally representative data set for permanently employed state health agency central office employees comprising over 10,000 responses, and a pilot data set with approximately 12,000 local and regional health department staff responses. PMID:26422490

  20. Novice performance of ultrasound-guided needle advancement: standard 38-mm transducer vs 25-mm hockey stick transducer.

    PubMed

    Davies, T; Townsley, P; Jlala, H; Dowling, M; Bedforth, N; Hardman, J G; McCahon, R A

    2012-08-01

    The optimal method to develop expertise in ultrasound-guided regional anaesthesia is unknown. Studies of laryngoscopic expertise in novices demonstrate that the choice of laryngoscope affects performance. In this study, we aimed to compare the effect of two different linear array transducers (38-mm standard vs 25-mm hockey stick) on novice performance of ultrasound-guided needle advancement. Following randomisation, participants watched a video model of expert performance of ultrasound-guided needle advancement. Recruits performed the modelled task on a turkey breast model. The median (IQR [range]) composite error score was statistically significantly larger for participants in the hockey stick transducer group compared with the standard transducer group; 10.0 (7.3-14.3 [2.5-29.0]) vs 7.5 (4.5-10.0 [2.0-28.0]) respectively, (p = 0.01). This study has demonstrated that performance of ultrasound-guided needle advancement by novice operators after simple video instruction is better (as assessed using a composite error score) with a standard 38-mm transducer than with a 25-mm hockey stick transducer. PMID:22506607

  1. MmTX1 and MmTX2 from coral snake venom potently modulate GABAA receptor activity.

    PubMed

    Rosso, Jean-Pierre; Schwarz, Jürgen R; Diaz-Bustamante, Marcelo; Céard, Brigitte; Gutiérrez, José M; Kneussel, Matthias; Pongs, Olaf; Bosmans, Frank; Bougis, Pierre E

    2015-02-24

    GABAA receptors shape synaptic transmission by modulating Cl(-) conductance across the cell membrane. Remarkably, animal toxins that specifically target GABAA receptors have not been identified. Here, we report the discovery of micrurotoxin1 (MmTX1) and MmTX2, two toxins present in Costa Rican coral snake venom that tightly bind to GABAA receptors at subnanomolar concentrations. Studies with recombinant and synthetic toxin variants on hippocampal neurons and cells expressing common receptor compositions suggest that MmTX1 and MmTX2 allosterically increase GABAA receptor susceptibility to agonist, thereby potentiating receptor opening as well as desensitization, possibly by interacting with the α(+)/β(-) interface. Moreover, hippocampal neuron excitability measurements reveal toxin-induced transitory network inhibition, followed by an increase in spontaneous activity. In concert, toxin injections into mouse brain result in reduced basal activity between intense seizures. Altogether, we characterized two animal toxins that enhance GABAA receptor sensitivity to agonist, thereby establishing a previously unidentified class of tools to study this receptor family. PMID:25675485

  2. MmTX1 and MmTX2 from coral snake venom potently modulate GABAA receptor activity

    PubMed Central

    Rosso, Jean-Pierre; Schwarz, Jürgen R.; Diaz-Bustamante, Marcelo; Céard, Brigitte; Gutiérrez, José M.; Kneussel, Matthias; Pongs, Olaf; Bosmans, Frank; Bougis, Pierre E.

    2015-01-01

    GABAA receptors shape synaptic transmission by modulating Cl− conductance across the cell membrane. Remarkably, animal toxins that specifically target GABAA receptors have not been identified. Here, we report the discovery of micrurotoxin1 (MmTX1) and MmTX2, two toxins present in Costa Rican coral snake venom that tightly bind to GABAA receptors at subnanomolar concentrations. Studies with recombinant and synthetic toxin variants on hippocampal neurons and cells expressing common receptor compositions suggest that MmTX1 and MmTX2 allosterically increase GABAA receptor susceptibility to agonist, thereby potentiating receptor opening as well as desensitization, possibly by interacting with the α+/β− interface. Moreover, hippocampal neuron excitability measurements reveal toxin-induced transitory network inhibition, followed by an increase in spontaneous activity. In concert, toxin injections into mouse brain result in reduced basal activity between intense seizures. Altogether, we characterized two animal toxins that enhance GABAA receptor sensitivity to agonist, thereby establishing a previously unidentified class of tools to study this receptor family. PMID:25675485

  3. pH gradients are not associated with tip growth in pollen tubes of Lilium longiflorum.

    PubMed

    Fricker, M D; White, N S; Obermeyer, G

    1997-08-01

    The cytoplasmic pH of growing pollen tubes of Lilium longiflorum Thunb. was measured using the pH-sensitive fluorescent dye 2',7'-bis-(carboxyethyl)-5(6')-carboxyfl uorescein and confocal fluorescence ratio imaging. The average cytoplasmic pH in the clear zone of the pollen tube tip was pH 7.11, and no consistent pH gradients were detected in the clear zone, averaging around -1.00 milli pH unit microm(-1), or along the first 50 microm of the tube (3.62 milli pH units microm[-1]). In addition, no correlation was observed between the absolute tip cytoplasmic pH or the pH gradient and the pollen tube growth rates. Shifts of external pH to more acidic pH values (pH 4.5) caused a relatively small acidification by 0.18 pH units, whereas a more alkaline external pH >7.0 caused a dramatic increase in cytoplasmic pH and growth stopped immediately. Stimulation of the plasma membrane H+-ATPase by fusicoccin, resulted in an increase of tube growth but no change in cytoplasmic pH. On the other hand, vanadate (250-500 microM), a putative inhibitor of the pump, stopped tube growth and a slight cytoplasmic alkalinisation of 0.1 pH units was observed. Vanadate also arrested fusicoccin-stimulated growth and stimulated an increased alkalinisation of around 0.2 pH units. External application of CaCl2 (10 mM) caused a small acidification of less than 0.1 pH units in the clear zone, whilst LaCl3 (250 microM) caused slight and rather variable perturbations in cytoplasmic pH of no more than 0.1 pH units. Both treatments stopped growth. It was inferred from these data that tip-acid cytoplasmic pH gradients do not play a central role in the organisation or maintenance of pollen tube tip growth. PMID:9264460

  4. Six-mm, plane-wave shock driver

    SciTech Connect

    Frank, A.M.; Chau, H.H.

    1993-06-14

    A 6-mm-diameter, plane-wave shock generation system has been developed and characterized as a laboratory bench driver for small scale experiments. The driver is based on an exploding-foil-driven slapper used either directly or to initiate an HE pellet. The slapper is driven by a low-inductance fireset with burst currents on the order of 30 kA and burst times of about 250ns, with a time-to-burst jitter under 10ns. Both the slapper impact and the detonation breakout of the pellet have been measured to be flat to within 10ns over a 6-mm diameter. Fabry-Perot velocimetry of impacts with LiF crystals were used to characterize shock pressures and durations. Attenuator plates and flyers driven by the HE were also measured, which provided a variety of available pulse shapes and data for modeling efforts.

  5. A 300-nm compact mm-wave linac FEL design

    SciTech Connect

    Nassiri, A.; Kustom, R.L.; Kang, Y.W.

    1995-12-31

    Microfabrication technology offers an alternative method for fabricating precision, miniature-size components suitable for use in accelerator physics and commercial applications. The original R&D work at Argonne, in collaboration with the University of Illinois at Chicago, has produced encouraging results in the area of rf accelerating structure design, optical and x-ray masks production, deep x-ray lithography (LIGA exposures), and precision structural alignments. In this paper we will present a design study for a compact single pass mm-linac FEL to produce short wavelength radiation. This system will consists of a photocathode rf gun operated at 30 GHz, a 50-MeV superconducting constant gradient structure operated at 60 GHz, and a microundulator with 1-mm period. Initial experimental results on a scale model rf gun and microundulator will be presented.

  6. A 10-mm MR-Conditional Unidirectional Pneumatic Stepper Motor.

    PubMed

    Chen, Yue; Mershon, Christopher D; Tse, Zion Tsz Ho

    2015-04-01

    Magnetic resonance (MR) conditional robotic devices facilitate accurate interventional procedures under MR imaging (MRI) guidance. For this purpose, a compact (10-mm diameter) MR-conditional stepper motor is presented. The device features seven key components, which contribute to a dense and easy to fabricate design. Alternating bursts of pressurized air and vacuum can drive the motor in 60° per step to achieve a maximum torque of 2.4 mNm. The relationship between torque and angular speed was investigated to demonstrate motor performance under different loading conditions. The stepper motor was tested in a GE 3T MRI scanner to verify its MR-compatibility. A maximum artifact width of 3 mm was measured in MRI images and a maximum signal-to-noise ratio reduction of 2.49% was recorded. PMID:25419104

  7. A 10-mm MR-Conditional Unidirectional Pneumatic Stepper Motor

    PubMed Central

    Chen, Yue; Mershon, Christopher D.; Tse, Zion Tsz Ho

    2014-01-01

    Magnetic resonance (MR) conditional robotic devices facilitate accurate interventional procedures under MR imaging (MRI) guidance. For this purpose, a compact (10-mm diameter) MR-conditional stepper motor is presented. The device features seven key components, which contribute to a dense and easy to fabricate design. Alternating bursts of pressurized air and vacuum can drive the motor in 60° per step to achieve a maximum torque of 2.4 mNm. The relationship between torque and angular speed was investigated to demonstrate motor performance under different loading conditions. The stepper motor was tested in a GE 3T MRI scanner to verify its MR-compatibility. A maximum artifact width of 3 mm was measured in MRI images and a maximum signal-to-noise ratio reduction of 2.49% was recorded. PMID:25419104

  8. Augmented approach to desirability function based on MM estimator

    NASA Astrophysics Data System (ADS)

    Midi, Habshah; Mustafa, Mohd Shafie; Fitrianto, Anuar

    2013-04-01

    The desirability function approach is commonly used in industry to tackle multiple response optimization problems. The shortcoming of this approach is that the variability in each predicted response is ignored. It is now evident that the actual response may fall outside the acceptable region even though the predicted response at the optimal solution has a high overall desirability score. An augmented approach to the desirability function (AADF) is put forward to rectify this problem. Nevertheless the AADF is easily affected by outliers since the AADF is constructed based on the Ordinary Least Squares (OLS) estimate which is not resistant to outliers. As an alternative, we propose a robust MM-estimator to estimate the parameters of the Response Surface Model (RSM) and incorporated the estimated parameters in the augmented approach framework. A numerical example is presented to assess the performance of the AADF-MM based method. The numerical results signify that the AADF-MM based is more efficient than the AADF-OLS based method.

  9. Projected Hybrid Orbitals: A General QM/MM Method

    PubMed Central

    2015-01-01

    A projected hybrid orbital (PHO) method was described to model the covalent boundary in a hybrid quantum mechanical and molecular mechanical (QM/MM) system. The PHO approach can be used in ab initio wave function theory and in density functional theory with any basis set without introducing system-dependent parameters. In this method, a secondary basis set on the boundary atom is introduced to formulate a set of hybrid atomic orbtials. The primary basis set on the boundary atom used for the QM subsystem is projected onto the secondary basis to yield a representation that provides a good approximation to the electron-withdrawing power of the primary basis set to balance electronic interactions between QM and MM subsystems. The PHO method has been tested on a range of molecules and properties. Comparison with results obtained from QM calculations on the entire system shows that the present PHO method is a robust and balanced QM/MM scheme that preserves the structural and electronic properties of the QM region. PMID:25317748

  10. Enhancing Paradynamics for QM/MM Sampling of Enzymatic Reactions.

    PubMed

    Lameira, Jerônimo; Kupchencko, Ilya; Warshel, Arieh

    2016-03-10

    Despite the enormous increase in computer power, it is still extremely challenging to obtain computationally converging sampling of ab initio QM/MM (QM(ai)/MM) free energy surfaces in condensed phases. The sampling problem can be significantly reduced by the use of the reference potential paradynamics (PD) approach, but even this approach still requires major computer time in studies of enzymatic reactions. To further reduce the sampling problem we developed here a new PD version where we use an empirical valence bond reference potential that has a minimum rather than a maximum at the transition state region of the target potential (this is accomplished conveniently by shifting the EVB of the product state). Hence, we can map the TS region in a more efficient way. Here, we introduce and validate the inverted EVB PD approach. The validation involves the study of the S(N)2 step of the reaction catalyzed by haloakene dehalogenase (DhlA) and the GTP hydrolysis in the RasGAP system. In addition, we have also studied the corresponding reaction in water for each of the systems described here and the reaction involving trimethylsulfonium and dimethylamine in solution. The results are encouraging and the new strategy appears to provide a powerful way of evaluating QM(ai)/MM activation free energies. PMID:26866994

  11. Feasibility studies of a compact mm-wave linac FEL

    SciTech Connect

    Nassiri, A.; Kustom, R.L.; Kang, Y.W.; Song, J.

    1995-12-31

    Short wavelength FELs impose stringent requirements on the quality of the electron beams. The key factor in obtaining a single-pass UV or x-ray FEL is the generation of small emittance electron beams with ultra-high brightness. The pioneering work at Los Alamos National Laboratory in the last decade has resulted in a dramatic improvement in the production of high electron beam brightness and small beam emittance using rf photocathode gun. The lower bound on the emittance of a 1-nC bunch without any emittance compensation is on the order of 3 {pi} mm-mrad. This is well within the emittance requirement being considered here. Although the original R&D work at Argonne, in collaboration with the University of Illinois at Chicago and University of Wisconsin-Madison, has produced encouraging results in the area of rf structure design, x-ray mask fabrication, and LIGA processing (Lithography, Electroforming, and Molding), the goal to prove feasibility has not yet been achieved. In this paper, we will present feasibility studies for a compact single-pass mm-linac FEL based on LIGA technology. This system will consist of a photocathode rf gun operated at 30 GHz, a 50-MeV superconducting constant gradient structure operated at 60 GHz, and a microundulator with 1-mm period.

  12. High Rate Proton Irradiation of 15mm Muon Drifttubes

    NASA Astrophysics Data System (ADS)

    Zibell, A.; Biebel, O.; Hertenberger, R.; Ruschke, A.; Schmitt, Ch.; Kroha, H.; Bittner, B.; Schwegler, P.; Dubbert, J.; Ott, S.

    2012-08-01

    Future LHC luminosity upgrades will significantly increase the amount of background hits from photons, neutrons 11.11d protons in the detectors of the ATLAS muon spectrometer. At the proposed LHC peak luminosity of 5\\cdot 1034(1)/(cm2s), background hit rates of more than 10(kHz)/(cm2) are expected in the innermost forward region, leading to a loss of performance of the current tracking chambers. Based on the ATLAS Monitored Drift Tube chambers, a new high rate capable drift tube detecor using tubes with a reduced diameter of 15mm was developed. To test the response to highly ionizing particles, a prototype chamber of 46 15mm drift tubes was irradiated with a 20 MeV proton beam at the tandem accelerator at the Maier-Leibnitz Laboratory, Munich. Three tubes in a planar layer were irradiated while all other tubes were used for reconstruction of cosmic muon tracks through irradiated and nonirradiated parts of the chamber. To determine the rate capability of the 15mm drifttubes we investigated the effect of the proton hit rate on pulse height, efficiency and spatial resolution of the cosmic muon signals.

  13. Light adaptation of invertebrate photoreceptors: influence of intracellular pH buffering capacity.

    PubMed Central

    Bolsover, S R; Brown, J E

    1982-01-01

    1. The possible role of pH changes in mediating light adaptation in Limulus ventral photoreceptor cells was studied by intracellular injection of zwitterionic pH buffers. The intracellular concentration of buffer was estimated by inclusion of a radioactive marker in the injection solution. 2. The light-induced increase of intracellular Ca2+ concentration was monitored by intracellular aequorin. The light-induced increase of Ca2+ concentration was not markedly altered by injection of pH buffer to an intracellular concentration of about 200 mM. 3. The progressive decrease in responsiveness during intracellular ionophoretic injection of Ca2+ was not markedly altered by injection of pH buffer to an intracellular concentration of about 200 mM. 4. Photoreceptors of both Limulus and Balanus were impaled with two micropipettes and voltage clamped. Membrane current induced by a prolonged steady illumination declined from an early transient to a plateau. This delayed decline of current indicates a light-induced reduction of sensitivity (i.e. light adaptation). The wave forms were similar before and after injection of pH buffer to an intracellular concentration of about 200 mM. 5. We conclude that it is unlikely that a light-induced change of cytosolic pH mediates light adaptation in Limulus (and Balanus) photoreceptors. PMID:7175745

  14. Miniature Chemical Optical Fiber Sensors For Ph Measurements

    NASA Astrophysics Data System (ADS)

    Boisde, G.; Perez, J. J.

    1987-10-01

    A miniature optode (diameter about 1 mm) was built with 200/280 all-silica fibers usable over long distances. The immobilized indicator is fixed on a cross-linked styrene/divinyl-benzene copolymer (XADZI). The sensors are constructed so that measurements can be taken either by absorption at many different points in the single optical fiber, or by reflection from the end of the fiber. A wide range of pH values are encountered with radioactive wastes, and experiments are performed either with bromophenol blue (3.0 to 6.0) or a double-indicator (thymol blue) between 0.8 and 3.2, and 9 and 13 pH, as well as other indicators. Lifetimes, reversibility and kinetics are considered. A new low-cost device is proposed for chemical process control and medical applications.

  15. Formation of asteroids from mm-cm sized grains

    NASA Astrophysics Data System (ADS)

    Carrera, D.; Johansen, A.; Davies, M. B.

    2014-03-01

    Context. Asteroids and comets are intricately connected to life in the universe. Asteroids are the building blocks of terrestrial planets; water-rich asteroids and comets are likely to be the primary source of water for Earth's oceans and other volatiles (Morbidelli et al. 2000; Hartogh et al. 2011); and they may play role in mass extinctions. Yet, the formation of these objects is poorly understood. There is mounting evidence that the traditional picture of the formation of asteroids must be revised. The size distribution of asteroids is hard to reconcile with a traditional bottomup formation scenario. Instead, asteroids may form top-down, with large 100 - 1000 km sized objects forming first by the gravitational collapse of dense clumps of small particles. Experiments and simulations suggest that dust grains cannot grow to sizes larger than mm-cm in protoplanetary disks (Zsom et al. 2010). Also, primitive meteorites from the asteroid belt contain a large mass fraction in chondrules of sizes from 0.1 mm to a few mm. Hence, it is desirable to find a model for asteroid formation from mm-sized particles. Aims. In this work, we model the dynamics of mm-cm sized grains in dust-enriched inner regions of protoplanetary disks. We model the dust-gas interaction to determine whether dust grains of this size can form dense, self-gravitating clouds that can collapse to form asteroids. Methods. We perform shearing box simulations of the inner disk using the Pencil Code (Brandenburg & Dobler 2002). The simulations start with a Solar-type solids-to-gas ratio of 0.01 and we gradually increase the particle concentration. In a real protoplanetary disk, solid particles are expected to migrate from the outer regions and concentrate in the inner disk. Results. Our simulations show that mm-sized particles can form very dense clumps, driven by a run-away convergence in the radial-drift flow of these particles - this dynamic is known as the streaming instability (Youdin & Goodman 2005

  16. The pH of antiseptic cleansers

    PubMed Central

    Kulthanan, Kanokvalai; Varothai, Supenya; Nuchkull, Piyavadee

    2014-01-01

    Background Daily bathing with antiseptic cleansers are proposed by some physicians as an adjunctive management of atopic dermatitis (AD). As atopic skin is sensitive, selection of cleansing products becomes a topic of concern. Objective Our purpose is to evaluate the pH of various antiseptic body cleansers to give an overview for recommendation to patients with AD. Methods Commonly bar and liquid cleansers consisted of antiseptic agents were measured for pH using pH meter and pH-indicator strips. For comparison, mild cleansers and general body cleansers were also measured. Results All cleansing bars had pH 9.8-11.3 except syndet bar that had neutral pH. For liquid cleansers, three cleansing agents had pH close to pH of normal skin, one of antiseptic cleansers, one of mild cleansers and another one of general cleansers. The rest of antiseptic cleansers had pH 8.9-9.6 while mild cleansers had pH 6.9-7.5. Syndet liquid had pH 7 and general liquid cleansers had pH 9.6. Conclusion The pH of cleanser depends on composition of that cleanser. Adding antiseptic agents are not the only factor determining variation of pH. Moreover, benefit of antiseptic properties should be considered especially in cases of infected skin lesions in the selection of proper cleansers for patients with AD. PMID:24527408

  17. Effects of acetic acid and arginine on pH elevation and growth of Bacillus licheniformis in an acidified cucumber juice medium.

    PubMed

    Yang, Zhenquan; Meng, Xia; Breidt, Frederick; Dean, Lisa L; Arritt, Fletcher M

    2015-04-01

    Bacillus licheniformis has been shown to cause pH elevation in tomato products having an initial pH below 4.6 and metabiotic effects that can lead to the growth of pathogenic bacteria. Because of this, the organism poses a potential risk to acidified vegetable products; however, little is known about the growth and metabolism of this organism in these products. To clarify the mechanisms of pH change and growth of B. licheniformis in vegetable broth under acidic conditions, a cucumber juice medium representative of a noninhibitory vegetable broth was used to monitor changes in pH, cell growth, and catabolism of sugars and amino acids. For initial pH values between pH 4.1 to 6.0, pH changes resulted from both fermentation of sugar (lowering pH) and ammonia production (raising pH). An initial pH elevation occurred, with starting pH values of pH 4.1 to 4.9 under both aerobic and anaerobic conditions, and was apparently mediated by the arginine deiminase reaction of B. licheniformis. This initial pH elevation was prevented if 5 mM or greater acetic acid was present in the brine at the same pH. In laboratory media, under favorable conditions for growth, data indicated that growth of the organism was inhibited at pH 4.6 with protonated acetic acid concentrations of 10 to 20 mM, corresponding to 25 to 50 mM total acetic acid; however, growth inhibition required greater than 300 mM citric acid (10-fold excess of the amount in processed tomato products) products under similar conditions. The data indicate that growth and pH increase by B. licheniformis may be inhibited by the acetic acid present in most commercial acidified vegetable products but not by the citric acid in many tomato products. PMID:25836398

  18. End design of the SSC 58 mm High Gradient Quadrupole

    SciTech Connect

    Caspi, S.

    1992-06-10

    The end'' design of the High Gradient Quad. was done with consideration to the integrated field harmonics, the iron contribution, and the maximum field at the conductor. Magnetic analysis was done on the return end only, however the physical dimension of the lead end were determined as well. Using the cross-section of the windings and Cook's program BEND, we generated the physical end windings around the return end. Placing a single wire at the center of each turn the integrated gradient was computed and iterating on the end block spacers the integrated harmonics minimized. The final geometry was then used for more, extensive calculations, such as the field at the conductor and the 3D field harmonics. For this detailed calculation we have placed a single line current at the center of each strand and included the iron contribution ({mu} = {infinity}), see Appendix C. With the termination of the iron serving as a reference, the maximum length of the inner and outer layers are 182 mm and 215 mm respectively. The magnetic length of the end was computed from the gradient function A{sub 2} and was found to be 142 mm. In reality we expect the physical length of the end to be somewhat larger, however this should have little or no effect on the magnetic length. The gradient in the straight section is 212.44 T/m at 7000 A and the integrated value of the gradient is -3.01665 E5 (G) in the end region marked by the magnetic length of the end. The respective integrated harmonics for the end 12 pole and 20 pole are -10.6658 (G/CM{sup 4}) and 0.7279 (G/cm{sup 8}) corresponding to b{sub 6} = 0.351 , b{sub 10} = -0.024 units. The above was computed from the values of A{sub 2}, A{sub 6}, and A{sub 10}.

  19. End design of the SSC 58 mm High Gradient Quadrupole

    SciTech Connect

    Caspi, S.

    1992-06-10

    The ``end`` design of the High Gradient Quad. was done with consideration to the integrated field harmonics, the iron contribution, and the maximum field at the conductor. Magnetic analysis was done on the return end only, however the physical dimension of the lead end were determined as well. Using the cross-section of the windings and Cook`s program BEND, we generated the physical end windings around the return end. Placing a single wire at the center of each turn the integrated gradient was computed and iterating on the end block spacers the integrated harmonics minimized. The final geometry was then used for more, extensive calculations, such as the field at the conductor and the 3D field harmonics. For this detailed calculation we have placed a single line current at the center of each strand and included the iron contribution ({mu} = {infinity}), see Appendix C. With the termination of the iron serving as a reference, the maximum length of the inner and outer layers are 182 mm and 215 mm respectively. The magnetic length of the end was computed from the gradient function A{sub 2} and was found to be 142 mm. In reality we expect the physical length of the end to be somewhat larger, however this should have little or no effect on the magnetic length. The gradient in the straight section is 212.44 T/m at 7000 A and the integrated value of the gradient is -3.01665 E5 (G) in the end region marked by the magnetic length of the end. The respective integrated harmonics for the end 12 pole and 20 pole are -10.6658 (G/CM{sup 4}) and 0.7279 (G/cm{sup 8}) corresponding to b{sub 6} = 0.351 , b{sub 10} = -0.024 units. The above was computed from the values of A{sub 2}, A{sub 6}, and A{sub 10}.

  20. Planetary observations at a wavelength of 1. 32 mm

    SciTech Connect

    Ulich, B.L.; Dickel, J.R.; De Pater, I.

    1984-12-01

    Observations at a wavelength of 1.32 mm have been made of the Jovian planets, Ceres, the satellites Callisto and Ganymede, and the HII region DR 21. The observed brightness temperatures are presented. Those of the Jovian planets agree with the values expected from model atmosphere calculations, except that of Jupiter, which is lower than expected. Ceres and the satellites do not have atmospheres so their emission arised in their subsurface layers. The observed brightness temperatures are intermediate between those measured at infrared and centimeter wavelengths. 30 references.

  1. Living with Omniback and the 8mm drive

    SciTech Connect

    Jones, M.C.

    1990-01-01

    Apollo's OmniBack backup system provides a convenient and effective way of storing network backup information on 8mm tape. In addition it has a journaling facility to write extensive log files, recording the backup process in almost any degree of detail desired. The directory structure and file names used are logical and well-defined. Summary files announce the degree of success of the backup as specified in the work file. The system will run unattended under the UNIX cron command, allowing the backup to be performed during the night when user demands on the network are small and most user files are free.

  2. Slow Slip Events on a 760 mm Long Granite Sample

    NASA Astrophysics Data System (ADS)

    Mclaskey, G.; Yamashita, F.

    2015-12-01

    We describe slow slip events and dynamic rupture events generated on a newly constructed large-scale biaxial friction apparatus at Cornell University that provide insights into the mechanisms of aseismic and seismic slip. We find that, under nominally similar experimental conditions, the 760 mm long granite sample sometimes slips in dynamic stick-slip events and sometimes relieves accumulated shear stress through slow slip events. To provide insights into this curious behavior and the underlying mechanisms, fault slip and shear stress are each measured at 8 locations along the 760 mm long fault. This allows us to map slow slip fronts and the nucleation and propagation of dynamic fault rupture. The granite sample is also instrumented with an array of piezoelectric sensors that are the laboratory equivalent of a seismic network. When the sample is loaded relatively slowly, at 0.03 MPa/s, slow slip occurs on large sections of the fault and the slow slipping region soon expands to the sample boundary. In this case, stress is released in a slow slip event with peak slip velocities < 2 mm/s. Alternatively, when one end of the sample is loaded rapidly (4 MPa/s), or the sample is allowed to heal in stationary contact for a few minutes, slow slip initiates near the load point and accelerates to slip velocities exceeding 200 mm/s before the slow slipping region expands all the way to the sample boundary. This produces a dynamic slip event (stick-slip). The dynamic slip events radiate seismic waves equivalent to a M = -2.5 earthquake. In contrast, the laboratory-generated slow slip events are predominantly aseismic and produce only bursts of tiny and discrete seismic events (M = -6) reminiscent of swarms of microseismicity. The experiments illustrate how a single fault can slide slowly and aseismically or rapidly and dynamically depending on stress state and loading conditions. We compare the behavior observed on this Cornell apparatus to the behavior of other large

  3. Herschel and Planck: surprises in the sub-mm band

    NASA Astrophysics Data System (ADS)

    González-Nuevo González, J.

    2015-05-01

    This paper focused on three of the most spectacular and almost unexpected results obtained from the observations in the sub-mm band coming from the ESA's Herschel and Planck missions: the detection of hundred of strongly lensed galaxies, the identification of high-z proto-clusters, and the study of the weak lensing signal through the cross-correlation analysis. Although, there were theoretical works that anticipate them, none of these interesting results appeared in the original scientific programs of both mission. For this reason we have called them ``surprises''.

  4. Gas Analysis by Fourier Transform Mm-Wave Spectroscopy

    NASA Astrophysics Data System (ADS)

    Harris, Brent J.; Steber, Amanda L.; Lehmann, Kevin K.; Pate, Brooks H.

    2013-06-01

    Molecular rotational spectroscopy of low pressure, room temperature gases offers high chemical selectivity and sensitivity with the potential for a wide range of applications in gas analysis. A strength of the technique is the potential to identify molecules that have not been previously studied by rotational spectroscopy by comparing experimental results to predictions of the spectroscopic parameters from quantum chemistry -6 so called library-free detection. The development of Fourier transform mm-wave spectrometers using high peak power (30 mW) active multiplier chain mm-wave sources brings new measurement capabilities to the analysis of complex gas mixtures. Strategies for gas analysis based on high-throughput mm-wave spectroscopy and arbitrary waveform generator driven mm-wave sources are described. Several new measurement capabilities come from the intrinsic time-domain measurement technique. High-sensitivity double-resonance measurements can be performed to speed the analysis of a complex gas sample containing several species. This technique uses a "pi-pulse" to selectively invert the population of two selected rotational energy levels and the effect of this excitation pulse on all other transitions in the spectrometer operating range is monitored using segmented chirped-pulse Fourier transform spectroscopy. This method can lead to automated determination of the molecular rotational constants. Rapid pulse duration scan experiments can be used to estimate the magnitude and direction of the dipole moment of the molecule from an unknown spectrum. Coherent pulse echo experiments, using the traditional Hahn sequence or two-color population recovery methods, can be used to determine the collisional relaxation rate of the unknown molecule. This rate determination improves the ability to estimate the mass of the unknown molecule from the determination of the Doppler dephasing rate. By performing a suite of automated, high-throughput measurements, there is the

  5. Synergies with ALMA and mm/submm facilities

    NASA Astrophysics Data System (ADS)

    Russell, H.; McNamara, B.; Fabian, A.

    2016-06-01

    New sub-mm facilities, such as ALMA, have opened up exciting new areas of astrophysics. I will review some of ALMA's exciting discoveries from the first five years of science including observations of massive molecular gas flows at the centres of nearby galaxies. Feedback from a central active galactic nucleus is thought to regulate the growth of massive galaxies by suppressing gas cooling and star formation. I will also focus on the potential contribution that XMM-Newton observations could make to these fields over the next decade.

  6. Dynamic impact analysis of the M1 105mm projectile

    SciTech Connect

    Walls, J.C.; Webb, D.S.

    1993-06-01

    Evaluation of the effects of {open_quotes}rough-handling{close_quotes}-induced stresses in the nose region of a 105mm artillery projectile was performed to determine if these stresses could have contributed to the premature explosion of a projectile during a Desert Shield training mission of the 101st Army Airborne in Saudi Arabia. The rough-handling evaluations were simulated by dynamic impact analysis. It was concluded that the combined residual stress and dynamic impact-induced stress would not be of sufficient magnitude to cause cracking of the projectile in the nose region.

  7. Dynamic impact analysis of the M1 105mm projectile

    SciTech Connect

    Walls, J.C.; Webb, D.S.

    1993-06-01

    Evaluation of the effects of [open quotes]rough-handling[close quotes]-induced stresses in the nose region of a 105mm artillery projectile was performed to determine if these stresses could have contributed to the premature explosion of a projectile during a Desert Shield training mission of the 101st Army Airborne in Saudi Arabia. The rough-handling evaluations were simulated by dynamic impact analysis. It was concluded that the combined residual stress and dynamic impact-induced stress would not be of sufficient magnitude to cause cracking of the projectile in the nose region.

  8. Influence of calcium, iron and pH on phosphate availability for microbial mineralization of organic chemicals

    SciTech Connect

    Robertson, B.K.; Alexander, M. )

    1992-01-01

    A study was conducted to determine some of the factors affecting the P requirement for the biodegradation of p-nitrophenol, phenol, and glucose by Pseudomonas and Corynebacterium strains. Mineralization of glucose was rapid and the Pseudomonas sp. grew extensively in solutions with 5 and 10 mM phosphate, but the rate and extent of degradation were low and the bacterial population never became abundant in media with 0.2 mM phosphate. Similar results were obtained with the Corynebacterium sp. growing in media containing p-nitrophenol or phenol and in solutions with a purified phosphate salt. The extent of growth of the Corynebacterium sp. was reduced with 2 or 10 mM phosphate in media containing high Fe concentrations. Ca at 5 mM but not 0.5 mM inhibited p-nitrophenol mineralization by the Corynebacterium sp. with phosphate concentrations from 0.2 to 5.0 mM. Phenol mineralization by the Pseudomonas sp. in medium with 0.2 mM phosphate was rapid at pH 5.2, but the bacteria had little or no activity at pH 8.0. In contrast, the activity was greater at pH 8.0 than at pH 5.2 when the culture contained 10 mM phosphate. These effects of pH were similar in media with 5 mM Ca or no added Ca. The authors conclude that the effect of P on bacterial degradation can be influenced by the pH and the concentrations of Fe and Ca.

  9. pH modulates arsenic toxicity in Bacillus licheniformis DAS-2.

    PubMed

    Tripti, K; Shardendu

    2016-08-01

    The toxic characteristics of arsenic species, As(V) and As(III) result in ecological risks. Arsenic tolerant bacterium was isolated and identified as the Bacillus licheniformis DAS-2 through 16SrDNA sequencing. B. licheniformis DAS-2 was efficient to tolerate and remove both the As(V)[MIC 8mM] and As(III)[MIC 6mM] from the growth medium. The potential for the removal/uptake of arsenic from the 3, 5 and 7mM As(V) enriched growth media was 100%, 60% and 35% respectively and from the 1, 3 and 5mM As(III) enrichment it was 100%, 99% and 58% respectively at neutral pH. 80% of uptake As(V) was reduced to As(III) in 3mM As(V) enrichment which was gradually decreased to only 17% at 7mM As(V) enrichment at neutral pH. The arsenic toxicity in B. licheniformis DAS-2 was found modulated by pH and was examined through alteration in growth, uptake/removal, reduction and measurement of chemical toxicity. PMID:27135959

  10. Acid loading test (pH)

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003615.htm Acid loading test (pH) To use the sharing features on this page, please enable JavaScript. The acid loading test (pH) measures the ability of the ...

  11. QM/MM Molecular Dynamics Studies of Metal Binding Proteins

    PubMed Central

    Vidossich, Pietro; Magistrato, Alessandra

    2014-01-01

    Mixed quantum-classical (quantum mechanical/molecular mechanical (QM/MM)) simulations have strongly contributed to providing insights into the understanding of several structural and mechanistic aspects of biological molecules. They played a particularly important role in metal binding proteins, where the electronic effects of transition metals have to be explicitly taken into account for the correct representation of the underlying biochemical process. In this review, after a brief description of the basic concepts of the QM/MM method, we provide an overview of its capabilities using selected examples taken from our work. Specifically, we will focus on heme peroxidases, metallo-β-lactamases, α-synuclein and ligase ribozymes to show how this approach is capable of describing the catalytic and/or structural role played by transition (Fe, Zn or Cu) and main group (Mg) metals. Applications will reveal how metal ions influence the formation and reduction of high redox intermediates in catalytic cycles and enhance drug metabolism, amyloidogenic aggregate formation and nucleic acid synthesis. In turn, it will become manifest that the protein frame directs and modulates the properties and reactivity of the metal ions. PMID:25006697

  12. Stress relaxation in SSC 50mm dipole coils

    SciTech Connect

    Rogers, D.; Markley, F.

    1992-04-01

    We are measuring the stress relaxation of SSC 50mm outer coils with the goal of predicting how much of the coil prestress will be lost while the coils are warehoused between manufacture and cooldown. We manufacture 3 inch (76.2mm) long segments of coil with the same materials and techniques that have been used for prototype coils. We are running four simultaneous tests in an attempt to separate the contributions of the different coil materials. Test one is a completely insulated coil section where the insulation is the all polyamide system being tested at Brookhaven; test two is a wire stack insulated only with the normal Kapton overwrap; test three is a stack of bare cable; and test four is a completely insulated normal coil section. All, except for the bare cable, include the ground insulation. The insulated coil sections are carefully dried before loading and testing in order to eliminate stress changes due to varying moisture content. The temperature dependence of the stress relaxation is being studied separately. Three companion papers presented at this conference will be: (1) Temperature dependence of the viscoelastic properties of SSC coil insulation'' (2) Measurement of the elastic modulus of Kapton perpendicular to the plane of the film at room and cryogenic temperatures'' (3) Theoretical methods for creep and stress relaxation studies of SSC coil.''

  13. Using 70-mm aerial photography to identify rangeland sites

    NASA Technical Reports Server (NTRS)

    Everitt, J. H.; Gerbermann, A. H.; Alaniz, M. A.; Bowen, R. L.

    1980-01-01

    A south Texas rangeland area was used as a study site to test the use of microdensitometry on 70-mm color-infrared and black-and-white photographs (scale 1:19,000) for distinguishing among 11 range sites (two brushland, seven grassland, two barren land) during the winter (February), spring (May), and summer (August) of 1976. Color-infrared photographs were also taken at a scale of 1:42,000 for the summer date. Film optical density readings were made on one color-infrared film with white light only. The best separations among density readings for all range sites were obtained using white light exposed on color-infrared film in the summer when vegetation was at peak foliage development. Results from this study indicate that 70-mm aerial color-infrared photography at a scale of 1:19,000 or 1:42,000 has good potential for identifying range sites in large and inaccessible areas, and could be a useful tool for range management.

  14. Resonant biaxial 7-mm MEMS mirror for omnidirectional scanning

    NASA Astrophysics Data System (ADS)

    Hofmann, U.; Aikio, M.; Janes, J.; Senger, F.; Stenchly, V.; Weiss, M.; Quenzer, H.-J.; Wagner, B.; Benecke, W.

    2013-03-01

    Low-cost automotive laser scanners for environment perception are needed to enable the integration of advanced driver assistant systems (ADAS) into all automotive vehicle segments, a key to reducing the number of traffic accidents on roads. An omnidirectional 360 degree laser scanning concept has been developed based on combination of an omnidirectional lens and a biaxial large aperture MEMS mirror. This omnidirectional scanning concept is the core of a small sized low-cost time-of-flight based range sensor development. This paper describes concept, design, fabrication and first measurement results of a resonant biaxial 7mm gimbal-less MEMS mirror that is electrostatically actuated by stacked vertical comb drives. Identical frequencies of the two resonant axes are necessary to enable the required circle scanning capability. A tripod suspension was chosen since it allows minimizing the frequency splitting of the two resonant axes. Low mirror curvature is achieved by a thickness of the mirror of more than 500 μm. Hermetic wafer level vacuum packaging of such large mirrors based on multiple wafer bonding has been developed to enable to achieve a large mechanical tilt angle of +/- 6.5 degrees in each axis. The 7mm-MEMS mirror demonstrates large angle circular scanning at 1.5kHz.

  15. Experimental demonstration of a 120-mm ram accelerator

    NASA Astrophysics Data System (ADS)

    Kruczynski, David L.

    1992-10-01

    Ram acceleration is an emerging propulsion technology in which a projectile similar in shape to the centerbody of a ramjet aircraft engine is injected at high speed into a tube filled with a combustible gaseous mixture. As the projectile moves into the tube, under supersonic conditions, shocks occur on and around the projectile. If the gases are then ignited either by the energy in the shock system or an external mechanism, the combustion around or behind the projectile can be self-sustaining. The net effect is to generate a localized high pressure region around and/or behind the projectile which produces acceleration. Work at the University of Washington, Seattle, has demonstrated velocities in excess of 2.6 km/s in 38-mm caliber, while theory predicts velocities above 7 km/s may be obtainable. A program was initiated at the Weapons Technology Directorate of the US Army Research Laboratory (formerly Ballistic Research Laboratory) to examine the scaling potential of ram acceleration for use as a high velocity, high mass, (i.e., high kinetic energy) launcher. Data from initial gas mixing tests and first firings through a 120-mm bore diameter ram accelerator with both inert and live fuel gases are presented. Initial comparisons with ram accelerators of smaller scale are made. Discussions of scaling parameters as currently understood will be presented.

  16. The pH dependency of relative ion permeabilities in the crayfish giant axon.

    PubMed

    Strickholm, A; Wallin, B G; Shrager, P

    1969-07-01

    The dependence of the membrane potential on potassium, chloride, and sodium ions, was determined at the pH's of 6.0, 7.5, and 9.0 for the resting and depolarized crayfish ventral nerve cord giant axon. In normal saline (external potassium = 5.4 mM), the dependence of the membrane potential on the external potassium ions decreased with lowered pH while that for chloride increased. In contrast, in the potassium depolarized axon (external potassium = 25 mM), the dependence of the membrane potential on external potassium was minimum around pH 7.5 and increased in either more acidic or basic pH. In addition, the dependence of the membrane potential on external chloride in the depolarized axon was maximum at pH 7.5 and decreased in either more acidic or basic pH. The sodium dependency of the membrane potential was small and relatively unaffected by pH or depolarization. The data are interpreted as indicating a reversible surface membrane protein-phospholipid conformation change which occurs in the transition from the resting to the depolarized axon. PMID:5791546

  17. Helical magneto-cumulative generator 280 mm in diameter

    NASA Astrophysics Data System (ADS)

    Demidov, V. A.; Kazakov, S. A.; Boriskin, A. S.; Vlasov, Yu. V.; Yanenko, V. A.; Nikolaev, N. I.; Volodchenkov, S. I.

    2015-01-01

    Several possibilities of preamplifier energy and power increasing are considered: using a more powerful (HMX-based) conical HE-charge in the central tube of the magneto-cumulative generator, using a magnetic flux finish pressing out device with axial initiation of the HE charge, and increasing the inner diameter of the helix. A magneto-cumulative generator (MCG) with a helix 280 mm in diameter (MCG-280) is developed. The new preamplifier has a power of ≈400 GW and is able to power a ten-element DMCG480 with an initial inductance of ≈0.2 µH by a current of ≈10 MA with a characteristic current rise time (by a factor of e at the final stage of its operation) τ e = 32 µs.

  18. Coil and iron design for SSC 50 mm magnet

    SciTech Connect

    Gupta, R.C.; Kahn, S.A.; Morgan, G.H.

    1990-01-01

    In this paper we present the design of the two dimensional coil and iron cross section, referred to as DSX201/W6733, for the 50 mm aperture dipole magnet being built at the Brookhaven National Laboratory for the Superconducting Super Collider (SSC). The computed values of the allowed field harmonics as a function of current, the quench performance predictions, the stored energy calculations, the effect of random errors on the coil placement and the Lorentz forces on the coil will be presented. The yoke has been optimized to reduce iron saturation effects on the field harmonics. We shall present the summary of this design which will include the expected overall performance of this cross section. 4 refs., 8 figs., 12 tabs.

  19. Coupling MM5 with ISOLSM: Development, testing, and applications

    SciTech Connect

    Riley, W.J.; Cooley, H.S.; He, Y.; Torn, M.S.

    2003-06-10

    Surface water and energy fluxes are tightly coupled with CO2 exchanges between the ecosystem and atmosphere. Other surface-to-atmosphere trace-gas exchanges of interest in climate change research (e.g., N2O, CH4, C18OO, and H218O) are also strongly impacted by surface energy exchanges. Further, land-use change has large effects on the surface energy balance and therefore the exchanges of these trace gases. To investigate these issues at the regional scale we have coupled MM5 (Grell et al. 1995) with ISOLSM (Riley et al. 2002, Riley et al. 2003), a land-surface model based on LSM1 (Bonan 1995).

  20. The Apollo 15 coarse fines (4-10 mm)

    NASA Technical Reports Server (NTRS)

    Ryder, Graham; Sherman, Sarah Bean

    1989-01-01

    A new catalog of the Apollo 15 coarse fines particles is presented. Powell's macroscopic descriptions, resulting from his 1972 particle by particle binocular examination of all of the Apollo 15 4 to 10 mm fines samples, are retained. His groupings are also retained, but petrographic, chemical, and other data from later analyses are incorporated into this catalog to better characterize individual particles and describe the groups. A large number of particles have no characterization beyond that done by Powell. Complete descriptions of the particles and all known references are provided. The catalog is intended for anyone interested in the rock types collected by Dave Scott and Jim Irwin in the Hadley-Appenine region, and particularly for researchers requiring sample allocations.

  1. 120-mm supercondcting quadrupole for interaction regions of hadron colliders

    SciTech Connect

    Zlobin, A.V.; Kashikhin, V.V.; Mokhov, N.V.; Novitski, I.; /Fermilab

    2010-05-01

    Magnetic and mechanical designs of a Nb{sub 3}Sn quadrupole magnet with 120-mm aperture suitable for interaction regions of hadron colliders are presented. The magnet is based on a two-layer shell-type coil and a cold iron yoke. Special spacers made of a low-Z material are implemented in the coil mid-planes to reduce the level of radiation heat deposition and radiation dose in the coil. The quadrupole mechanical structure is based on aluminum collars supported by an iron yoke and a stainless steel skin. Magnet parameters including maximum field gradient and field harmonics, Nb3Sn coil pre-stress and protection at the operating temperatures of 4.5 and 1.9 K are reported. The level and distribution of radiation heat deposition in the coil and other magnet components are discussed.

  2. Quantum Phase Slips in 6 mm Long Niobium Nanowire.

    PubMed

    Zhao, Weiwei; Liu, Xin; Chan, M H W

    2016-02-10

    Transport measurements were made to study the superconducting transition of four 6 mm long niobium nanowires with different cross-sectional dimensions. A low-temperature residual resistance tail measured with an excitation current of 5 nA is found in the thinnest wire down to 50 mK or 7.7% of Tc of Nb. The functional form of the residual resistance is consistent with quantum phase slip (QPS) processes. Resistance measured at high bias excitation current switches among many discrete values that are well below the normal state resistance. These discrete resistance values as a function of temperature fall into several parallel curves all showing QPS-like decay in the low temperature limit similar to that found at low current. The coexistence of QPS-like resistance tails and resistance jumps found in the same wire unifies results from previous experiments where these two distinct sets of evidence for QPS are exclusive of each other. PMID:26788964

  3. A densitometric analysis of commercial 35mm films

    NASA Technical Reports Server (NTRS)

    Hammond, Ernest C., Jr.; Ruffin, Christopher, III

    1989-01-01

    IIaO films have been subjected to various sensitometric tests. The have included thermal and aging effects and reciprocity failure studies. In order to compare the special IIaO film with popular brands of 35 mm films and their possible use in astrophotography, Agfa, Fuji and Kodak print and slide formats, as well as black and white and color formats, were subjected to sensitometric, as well as densitometric analysis. A scanning electron microscope was used to analyze grain structure size, and shape as a function of both speed and brand. Preliminary analysis of the grain structure using an ISI-SS40 scanning electron microscope indicates that the grain sizes for darker densities are much larger than the grain size for lighter densities. Researchers analyze the scanning electron microscope findings of the various grains versus densities as well as enhancement of the grains, using the IP-8500 Digital Image Processor.

  4. A densitometric analysis of commercial 35mm films

    NASA Astrophysics Data System (ADS)

    Hammond, Ernest C., Jr.; Ruffin, Christopher, III

    IIaO films have been subjected to various sensitometric tests. The have included thermal and aging effects and reciprocity failure studies. In order to compare the special IIaO film with popular brands of 35 mm films and their possible use in astrophotography, Agfa, Fuji and Kodak print and slide formats, as well as black and white and color formats, were subjected to sensitometric, as well as densitometric analysis. A scanning electron microscope was used to analyze grain structure size, and shape as a function of both speed and brand. Preliminary analysis of the grain structure using an ISI-SS40 scanning electron microscope indicates that the grain sizes for darker densities are much larger than the grain size for lighter densities. Researchers analyze the scanning electron microscope findings of the various grains versus densities as well as enhancement of the grains, using the IP-8500 Digital Image Processor.

  5. Calibration of a HTS Based LOX 400 mm Level Sensor

    NASA Astrophysics Data System (ADS)

    Karunanithi, R.; Jacob, S.; Nadig, D. S.; Prasad, M. V. N.; Gour, Abhay S.; Pankaj, S.; Gowthaman, M.; Sudharshan, H.

    The measurement of the cryogen level in a cryostage of space crafts is crucial. At the same time the weight of the sensor should be small as it affects the payload fraction of the space craft. An attempt to develop a HTS based level sensor of 400 mm for Liquid Oxygen (LOX) measurement was made. In the initial phase of testing, loss of superconductivity of HTS wire in LOX inside a cryostat was noticed. Thus, a new four wall cryostat was designed to have a stable LOX level to provide thermal stability to the HTS based LOX sensor. The calibration of the developed sensor was carried out against capacitance level sensor which was pre calibrated using diode array to verify its linearity and performance for different current excitation levels. The calibrations were carried out without heater wires. The automatic data logging was accomplished using a program developed in LabVIEW 11.0.

  6. Generation of mm- and Sub mm-wave Bessel Beams Using DOE's Designed by BOR-FDTD Method and MGA

    NASA Astrophysics Data System (ADS)

    Yu, Y. Z.; Dou, W. B.

    2009-02-01

    A new way for generating Bessel beams at mm and sub mm-wavelengths is presented in this paper, in which diffractive optical elements (DOE’s) are designed for converting incident Gaussian beams into Bessel beams. In order to reduce the computational burden and therefore improve the design efficiency, two measures are adopted in our design. One is a body-of-revolution finite-difference time-domain (BOR-FDTD) method that uses a two-dimensional (2-D) solution space instead of a full 3-D space and thereby saves tremendous computational resources, and that is utilized to calculate the fields diffracted by the DOE’s. The other is a microgenetic algorithm (MGA) that has been proved to be more effective than the conventional GA, and that is employed for accelerative optimization. The utility of the present design tool, which combines a MGA with a BOR-FDTD method, is demonstrated by three examples. Numerical simulation results indicate that the designed DOE’s can not only flexibly generate zero- or higher- order Bessel beams when compared with axicons, but also have higher diffraction efficiencies when compared with amplitude holograms.

  7. Comparison of less lethal 40 mm sponge projectile and the 37 mm projectile for injury assessment on human thorax

    NASA Astrophysics Data System (ADS)

    Nsiampa, N.; Robbe, C.; Oukara, A.; Papy, A.

    2012-08-01

    Since there is an increasing interest in avoiding human body injury in diverse situations like crowd control or peacekeeping missions, less lethal ammunition are more and more used. In this study we focus only on kinetic energy non-lethal (KENLW) projectiles. Their desired effects on human body are the temporary incapacitation through blunt trauma. There are different types of KENLW projectiles ranging from rigid to deformable projectiles. Unfortunately, the effects of such projectiles are not really well known as it is difficult to measure the force transmitted to the human body or the related deformation. Because the potential of injury excludes human living tests, tests are performed on cadavers, animals or human tissue surrogates. Besides these tests, numerical simulations are more and more used to gain more understanding, to assess or to predict the effects of this kind of projectile on human body. In this paper a comparison based on the viscous criterion between the 37 mm rigid projectile and the 40 mm sponge projectile was made.

  8. Modelling and performance of Nb SIS mixers in the 1.3 mm and 0.8 mm bands

    NASA Technical Reports Server (NTRS)

    Karpov, A.; Carter, M.; Lazareff, B.; Billon-Pierron, D.; Gundlach, K. H.

    1992-01-01

    We describe the modeling and subsequent improvements of SIS waveguide mixers for the 200-270 and 330-370 GHz bands (Blundell, Carter, and Gundlach 1988, Carter et al 1991). These mixers are constructed for use in receivers on IRAM radiotelescopes on Pico Veleta (Spain, Sierra Nevada) and Plateau de Bure (French Alps), and must meet specific requirements. The standard reduced height waveguide structure with suspended stripline is first analyzed and a model is validated through comparison with scale model and working scale measurements. In the first step, the intrinsic limitations of the standard mixer structure are identified, and the parameters are optimized bearing in mind the radioastronomical applications. In the second step, inductive tuning of the junctions is introduced and optimized for minimum noise and maximum bandwidth. In the 1.3 mm band, a DSB receiver temperature of less than 110 K (minimum 80 K) is measured from 180 through 260 GHz. In the 0.8 mm band, a DSB receiver temperature of less than 250 K (minimum 175 K) is obtained between 325 and 355 GHz. All these results are obtained with room-temperature optics and a 4 GHz IF chain having a 500 MHz bandwidth and a noise temperature of 14 K.

  9. Error Growth Rate in the MM5 Model

    NASA Astrophysics Data System (ADS)

    Ivanov, S.; Palamarchuk, J.

    2006-12-01

    The goal of this work is to estimate model error growth rates in simulations of the atmospheric circulation by the MM5 model all the way from the short range to the medium range and beyond. The major topics are addressed to: (i) search the optimal set of parameterization schemes; (ii) evaluate the spatial structure and scales of the model error for various atmospheric fields; (iii) determine geographical regions where model errors are largest; (iv) define particular atmospheric patterns contributing to the fast and significant model error growth. Results are presented for geopotential, temperature, relative humidity and horizontal wind components fields on standard surfaces over the Atlantic-European region during winter 2002. Various combinations of parameterization schemes for cumulus, PBL, moisture and radiation are used to identify which one provides a lesser difference between the model state and analysis. The comparison of the model fields is carried out versus ERA-40 reanalysis of the ECMWF. Results show that the rate, at which the model error grows as well as its magnitude, varies depending on the forecast range, atmospheric variable and level. The typical spatial scale and structure of the model error also depends on the particular atmospheric variable. The distribution of the model error over the domain can be separated in two parts: the steady and transient. The first part is associated with a few high mountain regions including Greenland, where model error is larger. The transient model error mainly moves along with areas of high gradients in the atmospheric flow. Acknowledgement: This study has been supported by NATO Science for Peace grant #981044. The MM5 modelling system used in this study has been provided by UCAR. ERA-40 re-analysis data have been obtained from the ECMWF data server.

  10. 300mm pilot line DSA contact hole process stability

    NASA Astrophysics Data System (ADS)

    Argoud, M.; Servin, I.; Gharbi, A.; Pimenta Barros, P.; Jullian, K.; Sanche, M.; Chamiot-Maitral, G.; Barnola, S.; Tiron, R.; Navarro, C.; Chevalier, X.; Nicolet, C.; Fleury, G.; Hadziioannou, G.; Asai, M.; Pieczulewski, C.

    2014-03-01

    Directed Self-Assembly (DSA) is today a credible alternative lithographic technology for semiconductor industry [1]. In the coming years, DSA integration could be a standard complementary step with other lithographic techniques (193nm immersion, e-beam, extreme ultraviolet). Its main advantages are a high pattern resolution (down to 10nm), a capability to decrease an initial pattern edge roughness [2], an absorption of pattern guide size variation, no requirement of a high-resolution mask and can use standard fab-equipment (tracks and etch tools). The potential of DSA must next be confirmed viable for high volume manufacturing. Developments are necessary to transfer this technology on 300mm wafers in order to demonstrate semiconductor fab-compatibility [3-7]. The challenges concern especially the stability, both uniformity and defectivity, of the entire process, including tools and Blok Co-Polymer (BCP) materials. To investigate the DSA process stability, a 300mm pilot line with DSA dedicated track (SOKUDO DUO) is used at CEALeti. BCP morphologies with PMMA cylinders in a PS matrix are investigated (about 35nm natural period). BCP selfassembly in unpatterned surface and patterned surface (graphoepitaxy) configurations are considered in this study. Unpatterned configuration will initially be used for process optimization and fix a process of record. Secondly, this process of record will be monitored with a follow-up in order to validate its stability. Steps optimization will be applied to patterned surface configurations (graphoepitaxy) for contact hole patterning application. A process window of contact hole shrink process will be defined. Process stability (CD uniformity and defectivity related to BCP lithography) will be investigated.

  11. MALT-45: The Galactic plane in 7mm

    NASA Astrophysics Data System (ADS)

    Jordan, Christopher; Walsh, Andrew; Voronkov, Maxim; Ellingsen, Simon

    2013-07-01

    MALT-45: The Galactic plane in 7mm MALT-45 is an untargeted Galactic plane survey searching for tracers of high mass star formation (HMSF) at 7mm. With the recent upgrades to the Australia Telescope Compact Array, we have been able to push the limits on observational efficiency to obtain a very sensitive blind survey in a short amount of time. Specifically, MALT-45 uses a fast on-the-fly mapping with 6 seconds per pointing, which results in a quarter-square-degree region being mapped in approximately 14 hours. Each region is Nyquist sampled and collects data in 12 spectral lines. The primary spectral lines of MALT-45 include: CS (1-0) - a high density gas tracer, which contrasts well with NH3 (1,1) from the similar HOPS survey; 44 GHz Class I methanol masers - the brightest of the Class I lines, it is poorly understood, and MALT-45 is one of the first surveys to thoroughly search for these masers; SiO (1-0) v=1,2,3 - typically associated with evolved stars, there have been rare associations with HMSF, and MALT-45 offers the potential to detect more. Other lines include thermal SiO (1-0) v=0, thermal methanol, C34S, OCS, and radio recombination lines H51a and H53a. Perhaps the most significant and innovative aspect of MALT-45 is the usage of ATCA autocorrelations. Each antenna of the ATCA is similar to Mopra, and by using all 6 antennae simultaneously, have a 6 fold increase in sensitivity per unit observation time. The autocorrelation data was only recently made available by the ATCA upgrade with the Compact Array Broadband Backend, and tools have been developed to allow this data processing. We present the first 5 square-degrees (l = 330 - 335, b = -0.5 - +0.5) of the Galactic plane mapped by MALT-45.

  12. Development of in situ CO2 and pH sensor for AUVs and ROVs

    NASA Astrophysics Data System (ADS)

    Nakano, Yoshiyuki; Kimoto, Hideshi; Miwa, Tetsuya; Yoshida, Hiroshi

    2013-04-01

    Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has been developing two-type autonomous underwater vehicles (AUVs): a cruising AUV and a working AUV, since October 2010. These vehicles will perform carbon dioxide (CO2) and pH observations to explore hydrothermal plume on seabed mineral resources and to monitor a leak of CO2 in carbon capture and storage (CCS) up to depth of 3,000 meters. We here have been developing the compact in situ CO2 and pH sensor (Hybrid CO2-pH sensor: HCS) for the AUVs to obtain vertical and horizontal distributions of CO2 and pH. The HCS consists of an aluminum pressure housing (diameter 84 mm, length 570 mm, weight 4 kg) and an acrylic silicon-oil filled, pressure-compensated vessel (diameter 90 mm, length 355 mm, weight 2 kg) containing valves and pump unit. The HCS is also useful for the observation by remotely operated vehicles (ROVs). The measured data were transmitted to the AUVs or ROVs by serial communications. We can monitor the data of in situ pCO2, pH and so on in real time on board. The measurement principle for the CO2 sensor is based on spectrophotometry. The pCO2 is calculated from the optical absorbance of the pH indicator solution equilibrated with CO2 in seawater through a gas permeable membrane. On the other hand, we adopt potentiometric analysis using original glass and reference electrodes as a pH sensor because of the most commonly used technique for sea water pH measurements and high-speed response (within 20 seconds). From simultaneously measured data of in situ pCO2 and pH, we can also calculate dissolved inorganic carbon (DIC) and total alkalinity (TA) as other carbonate species in the ocean. The resolutions of HCS are 1 μatm for pCO2 and 0.001 pH. In the laboratory experiment, the HCS obtained precisions within 3 μatm and within 0.01 pH, respectively. Our first in situ observational test of the HSC with cruising AUV was made in the coast of the Japan Sea last August. And also first in situ test

  13. Mu d-directed lacZ fusions regulated by low pH in Escherichia coli.

    PubMed Central

    Slonczewski, J L; Gonzalez, T N; Bartholomew, F M; Holt, N J

    1987-01-01

    Methods were devised to isolate strains of Escherichia coli containing Mu d (lacZ Kmr) operon fusions regulated by external pH and by internal pH. External acid-inducible fusions (exa) were detected by plating a Mu d fusion pool on Luria broth with 5-bromo-4-chloro-3-indolyl-beta-D-galactoside, buffered at pH 7.4, and then replica plating on the same medium buffered at pH 5.5. Two exa strains showed induction by external acidification, up to 800-fold and 90-fold. Induction of both fusions was maximal at pH 5.6 and minimal over pH 7.0 to 8.3. There was no induction by membrane-permeable weak acids which depress internal pH at constant external pH. Anaerobiosis increased the steady-state level of transcription of exa-1 5-fold and of exa-2 2.5-fold at low external pH. Internal acid-inducible fusions (ina) were detected by plating a Mu d fusion pool on MacConkey medium, pH 6.8, and then replica plating with 15 mM benzoate. Two ina strains showed 10-fold induction by 20 mM benzoate at external pH 7.0. Similar results were obtained with other weak acids; their relative potency (salicylate greater than benzoate greater than dimethoxazoledinedione) was consistent with their relative ability to depress internal pH. In the absence of a weak acid, external pH had almost no effect over the pH range 5.5 to 8.0. Anaerobiosis did not affect ina induction. To our knowledge, this is the first report of E. coli genes induced specifically by internal but not external acidification and the first report of gene fusions induced by external acidification but not by weak acids. PMID:2954947

  14. Low pH affects survival, growth, size distribution, and carapace quality of the postlarvae and early juveniles of the freshwater prawn Macrobrachium rosenbergii de Man

    NASA Astrophysics Data System (ADS)

    Kawamura, Gunzo; Bagarinao, Teodora; Yong, Annita Seok Kian; Chen, Chiau Yu; Noor, Siti Norasidah Mat; Lim, Leong Seng

    2015-06-01

    Acidification of rain water caused by air pollutants is now recognized as a serious threat to aquatic ecosystems. We examined the effects of low pH (control pH 7.5, pH 6, pH 5, pH 4) on the survival, growth, and shell quality of Macrobrachium rosenbergii postlarvae and early juveniles in the laboratory. Hatcheryproduced postlarvae (PL 5) were stocked at 250 PL per aquarium, acclimated over 7 d to experimental pH adjusted with hydrochloric acid, and reared for 30 d. Dead specimens were removed and counted twice a day. After 27 d rearing, all specimens were measured for total length and body weight. Carapace quality was assessed by spectrophotometry. Survival of juveniles was highest at pH 6 (binomial 95% confidence interval 79 - 89%) followed by control pH 7.5 (56 - 68%) and pH 5 (50 - 60%) and was lowest for unmetamorphosed postlarvae and juveniles at pH 4 (43 - 49%). The final median total length and body weight of juveniles were similar at control pH 7.5 (18.2 TL, 50.2 mg BW) and pH 6 (17.7 mm TL, 45.0 mg BW) but significantly less at pH 5 (16.7 mm TL, 38.2 mg BW); at pH 4, the postlarvae did not metamorphose and measured only 9.8 mm TL, 29.3 mg BW. Length frequency distribution showed homogeneous growth at pH 6, positive skew at control pH 7.5 and pH 5, and extreme heterogeneity at pH 4. The carapace showed different transmittance spectra and lower total transmittance (i.e. thicker carapace) in juveniles at pH 7.5, pH 6, and pH 5 than in unmetamorphosed postlarvae and juveniles with thinner carapace at pH 4. Thus, survival, growth, size distribution, and carapace quality of M. rosenbergii postlarvae and early juveniles were negatively affected by pH 5 and especially pH 4. The thinner carapace of the survivors at pH 4 was mostly due to their small size and failure to metamorphose. Natural waters affected by acid rain could decimate M. rosenbergii populations in the wild.

  15. Evaluation of the 11CO2 positron emission tomographic method for measuring brain pH. I. pH changes measured in states of altered PCO2.

    PubMed

    Buxton, R B; Alpert, N M; Babikian, V; Weise, S; Correia, J A; Ackerman, R H

    1987-12-01

    The 11CO2 method for measuring local brain pH with positron emission tomography (PET) has been experimentally evaluated, testing the adequacy of the kinetic model and the ability of the method to measure changes in brain pH. Plasma and tissue time/activity curves measured during and following continuous inhalation of 11CO2 were fit with a kinetic model that includes effects of tissue pH, blood flow, and fixation of CO2 into compounds other than dissolved gas and bicarbonate ions. For each of ten dogs, brain pH was measured with PET at two values of PaCO2 (range 21-67 mm Hg). The kinetic model fit the data well during both inhalation and washout of the label, with residual root mean square (RMS) deviations of the model from the measurements consistent with the statistical quality of the PET data. Brain pH calculated from the PET data shows a linear variation with log(PaCO2). These results were in good agreement with previously reported measurements of brain pH, both in absolute value and in variation with PCO2. The interpretation of these pH values in normal and pathological states is discussed. PMID:3121647

  16. [Relation of Lac promotor and the expression of cholera toxin subunit B gene in recombinant Escherichia coli MM2].

    PubMed

    Fang, H; Zhao, S; Yu, G; Ma, Q

    1997-08-01

    Effects of different carbon sources including glucose, lactate and acetate and IPTG induction on the expression of ctb gene, which is on the downstream of lac promotor, in recombinant Escherichia coli MM2 were studied. In medium YC were added 0.048mol/L glucose, 0.102mol/L lactate or 0.167mol/L acetate which separately produce the same energy in the condition of complete oxidization. Addition of glucose largely decreased the expression level of ctb gene because of decrease of pH during culture process. Addition of lactate increased the expression level of ctb gene by 1.15 fold and did not inhibit the growth of MM2 strain. Addition of acetate increasd the expression level of ctb gene by 0.97 fold and inhibited the growth of MM2 strain. Induction by IPTG at different time and different concentration did not increase the expression level of ctb gene, so the lac promotor had no or a little influence upon the expression of ctb gene in recombinant MM2 strain. PMID:9863203

  17. Phosphocreatine kinetics at the onset of contractions in skeletal muscle of MM creatine kinase knockout mice

    NASA Technical Reports Server (NTRS)

    Roman, Brian B.; Meyer, Ronald A.; Wiseman, Robert W.

    2002-01-01

    Phosphocreatine (PCr) depletion during isometric twitch stimulation at 5 Hz was measured by (31)P-NMR spectroscopy in gastrocnemius muscles of pentobarbital-anesthetized MM creatine kinase knockout (MMKO) vs. wild-type C57B (WT) mice. PCr depletion after 2 s of stimulation, estimated from the difference between spectra gated to times 200 ms and 140 s after 2-s bursts of contractions, was 2.2 +/- 0.6% of initial PCr in MMKO muscle vs. 9.7 +/- 1.6% in WT muscles (mean +/- SE, n = 7, P < 0.001). Initial PCr/ATP ratio and intracellular pH were not significantly different between groups, and there was no detectable change in intracellular pH or ATP in either group after 2 s. The initial difference in net PCr depletion was maintained during the first minute of continuous 5-Hz stimulation. However, there was no significant difference in the quasi-steady-state PCr level approached after 80 s (MMKO 36.1 +/- 3.5 vs. WT 35.5 +/- 4.4% of initial PCr; n = 5-6). A kinetic model of ATPase, creatine kinase, and adenylate kinase fluxes during stimulation was consistent with the observed PCr depletion in MMKO muscle after 2 s only if ADP-stimulated oxidative phosphorylation was included in the model. Taken together, the results suggest that cytoplasmic ADP more rapidly increases and oxidative phosphorylation is more rapidly activated at the onset of contractions in MMKO compared with WT muscles.

  18. GDx-MM: An imaging Mueller matrix retinal polarimeter

    NASA Astrophysics Data System (ADS)

    Twietmeyer, Karen Marie

    2007-12-01

    Retinal diseases are a major cause of blindness worldwide. Although widely studied, disease mechanisms are not completely understood, and diagnostic tests may not detect disease early enough for timely intervention. The goal of this research is to contribute to research for more sensitive diagnostic tests that might use the interaction of polarized light with retinal tissue to detect subtle changes in the microstructure. This dissertation describes the GDx-MM, a scanning laser polarimeter which measures a complete 16-element Mueller matrix image of the retina. This full polarization signature may provide new comparative information on the structure of healthy and diseased retinal tissue by highlighting depolarizing structures as well as structures with varying magnitudes and orientations of retardance and diattenuation. The three major components of this dissertation are: (1) Development of methods for polarimeter optimization and error analysis; (2) Design, optimization, assembly, calibration, and validation of the GDx-MM polarimeter; and (3) Analysis of data for several human subjects. Development involved modifications to a Laser Diagnostics GDx, a commercially available scanning laser ophthalmoscope with incomplete polarization capability. Modifications included installation of polarization components, development of a data acquisition system, and implementation of algorithms to convert raw data into polarization parameter images. Optimization involved visualization of polarimeter state trajectories on the Poincare sphere and a condition number analysis of the instrument matrix. Retinal images are collected non-invasively at 20 mum resolution over a 15° visual field in four seconds. Validation of the polarimeter demonstrates a polarimetric measurement accuracy of approximately +/- 5%. Retinal polarization data was collected on normal human subjects at the University of Arizona and at Indiana University School of Optometry. Calculated polarization parameter

  19. Improved mm-wave photometry for kinetic inductance detectors

    NASA Astrophysics Data System (ADS)

    Calvo, M.; Roesch, M.; Désert, F.-X.; Monfardini, A.; Benoit, A.; Mauskopf, P.; Ade, P.; Boudou, N.; Bourrion, O.; Camus, P.; Cruciani, A.; Doyle, S.; Hoffmann, C.; Leclercq, S.; Macias-Perez, J. F.; Ponthieu, N.; Schuster, K. F.; Tucker, C.; Vescovi, C.

    2013-03-01

    Context. We have developed a dual-band (140 and 220 GHz) mm-wave imaging camera based on superconducting kinetic inductance detector (KID) arrays. Each array contains 132 superconducting resonators whose resonant frequencies are shifted by mm-wave photons absorption. The read out is achieved with a single electronics chain per band, taking advantage of the intrinsic KID frequency-domain multiplexability. The arrays are easily scalable and well adapted for future large format focal plane instruments. NIKA (formerly Néel IRAM KID Array, now New IRAM KID Array) has been specifically designed for the IRAM 30 m telescope at Pico Veleta, and is one of the first instruments using KIDs to have made measurements of astronomical sources. Aims: In this Letter we describe the solutions adopted to improve the calibration accuracy and the sensitivity of the instrument, and we report on the outcome of the 3rd NIKA observing run of October, 2011. Methods: We use a fast electronic modulation of the readout tone for each KID pixel in order to linearize the instrument calibration, which we track with measurements of planets. We also adopt a new design of the KIDs, sensitive to both polarizations, to increase the amount of radiation absorbed and thus the optical efficiency of the system. Results: We measured an average sensitivity on the sky of 21 mJys0.5 per beam at 140 GHz and 140 mJys0.5 at 220 GHz in the best observing conditions (τ220 ≃ 0.2) after atmospheric noise decorrelation. The sensitivity at 220 GHz was limited by the atmospheric attenuation and loading as well as a reduction in the spectral bandwidth due to a misplaced filter. We found the repeatability in the photometry over the entire observing run to be better than 10% in both bands, thus demonstrating a significant improvement over the previous runs. We also find good agreement between NIKA measurements of faint astronomical sources and previous measurements of the same sources.

  20. 100 mm dynamic stencils pattern sub-micrometre structures.

    PubMed

    Savu, Veronica; Xie, Shenqi; Brugger, Juergen

    2011-07-01

    Dynamic stencil lithography uses a moving shadow-mask to draw patterns by having directionally evaporated material deposited through the stencil apertures onto the substrate. Sub-micrometre, two-dimensional patterning is demonstrated at full 100 mm wafer scale, with two examples emphasizing this technique's unique features. Structures having a width-modulated height below a certain aperture size are fabricated by moving the stencil according to a two-dimensional trajectory. Variable-period gratings are obtained by translating a row of apertures at different orientations with respect to the row's axis. Despite the long deposition sequences one could envision for a stencil in dynamic mode, the apertures' active life-time in the sub-micrometre domain remains limited by the material's accretion on the membrane, resulting in the eventual clogging of the openings. A novel solution to this problem containing a micro-heater embedded in the membrane is described and its effectiveness in preventing material from clogging the apertures is demonstrated. PMID:21674118

  1. Mapping wetlands on beaver flowages with 35-mm photography

    USGS Publications Warehouse

    Kirby, R.E.

    1976-01-01

    Beaver flowages and associated wetlands on the Chippewa National Forest, north-central Minnesota, were photographed from the ground and from the open side window of a small high-wing monoplane. The 35-mm High Speed Ektachrome transparencies obtained were used to map the cover-type associations visible on the aerial photographs. Nearly vertical aerial photos were rectified by projecting the slides onto a base map consisting ofcontrol points located by plane-table survey. Maps were prepared by tracing the recognizable stands of vegetation in the rectified projection at the desired map scale. Final map scales ranging from 1:260 to 1:571 permitted identification and mapping of 26 cover-type associations on 10 study flowages in 1971. This cover-mapping technique was economical and substituted for detailed ground surveys. Comparative data from 10 flowages were collected serially throughout the entire open-water season. Although developed for analysis of waterfowl habitat, the technique has application to other areas of wildlife management and ecological investigation.

  2. S-I-S mm-wave mixers and detectors

    NASA Astrophysics Data System (ADS)

    Jillie, D. W.; Kroger, H.; Smith, L. N.; Shaw, D. M.

    1983-10-01

    This program is an effort to achieve the ultimate goal of fabricating refractory superconducting S-I-S mixer devices for operation in mm-wave receivers in the quantum mode and in the 8-10 K temperature range. The following progress has been made toward the above goal: (1) development of in-house capability of depositing niobium carbonitride films (Nb (x) N(y) of device quality with transition temperatures to approx. 16 K; (2) development of NbC(x)N(y):aSi:Nb and NbC(x)N(y):Ge:Nb devices of very high quality; (3) fabrication and successful operation of niobium based S-I-S mixer chips; and (4) fabrication and evaluation of aSi and Ge barrier all-NbC(x)N(y) devices. NbC(x)N(y):Ge:Nb devices have been fabricated with chemical vapor deposited (CVD) polycrystalline arsenic-doped germanium barriers. All-Nb-S-I-S mixer chips were fabricated and sent to Goddard Institute for Space Studies to be evaluated. The noise temperature was approx. 60 K and the conversion loss of 5 dB. These results are comparable to Pb alloy junction results. A second-generation mixer was designed by GISS.

  3. The LMT Galaxies' 3 mm Spectroscopic Survey: First Results

    NASA Astrophysics Data System (ADS)

    Rosa González, D.; Schloerb, P.; Vega, O.; Hunt, L.; Narayanan, G.; Calzetti, D.; Yun, M.; Terlevich, E.; Terlevich, R.; Mayya, Y. D.; Chávez, M.; Montaña, A.; Pérez García, A. M.

    2014-09-01

    The molecular phase of the interstellar medium (ISM) in galaxies offers fundamental insight for understanding star-formation processes and how stellar feedback affects the nuclear activity of certain galaxies. We present here Large Millimeter Telescope spectra obtained with the Redshift Search Receiver, a spectrograph that covers simultaneously the 3 mm band from 74 to 111 GHz with a spectral resolution of around 100 km/s. Our selected galaxies, have been detected previously in HCN, and have different degrees of nuclear activity — one normal galaxy (NGC 6946), the starburst prototype (M82) and two %ultraluminous infrared galaxies (ULIRGs, IRAS 17208-0014 and Mrk 231). We plotted our data in the HCO+/HCN vs. HCN/13CO diagnostic diagram finding that NGC 6946 and M82 are located close to other normal galaxies; and that both IRAS 17208-0014 and Mrk 231 are close to the position of the well known ULIRG Arp 220 reported by Snell et al. (2011). We found that in Mrk 231 - a galaxy with a well known active galactic nucleus - the HCO+/HCN ratio is similar to the ratio observed in normal galaxies.

  4. Latest developments with the 400 MM bore Pielstick engine

    SciTech Connect

    Chellini, R.

    1995-06-01

    For over forty years, S.E.M.T. Pielstick has been manufacturing the 400 mm bore, four-stroke, medium-speed PC diesel engine. The evolution has continued up to the present and the latest issue is the PC2-6B design, featuring an output of 615 kW per cylinder. This result was made possible by a multifold, ongoing development program. Experience, gained on the nearly 4000 PC engines built so far for marine and stationary applications, was combined with technological progress in engine design, materials and components. These elements all contribute to make the present engines, not only over three times as powerful, but also more reliable and more economical to run, featuring a lower specific fuel consumption and requiring less maintenance. The 1000 hours endurance test on the three-cylinder experimental engine has allowed tuning of the PC2-6B to the nominal power of 615 kW/cylinder at 500 r/min and verification of safety margins with the engine running at 600 r/min. The same program highlighted the low emission values of the new engine, summarized as: NO{sub x}, < 6 g/kWh; CO, $LS 0.6 g/kWh; HC, < 0.5 g/kWh; and smoke, < 0.15{degree} Bosch.

  5. COSMOG: Cosmology Oriented Sub-mm Modeling of Galactic Foregrounds

    NASA Technical Reports Server (NTRS)

    Kashlinsky, A.; Leisawitz, D.

    2004-01-01

    With upcoming missions in mid- and far-Infrared there is a need for software packages to reliably simulate the planned observations. This would help in both planning the observation and scanning strategy and in developing the concepts of the far-off missions. As this workshop demonstrated, many of the new missions are to be in the far-IR range of the electromagnetic spectrum and at the same time will map the sky with a sub-arcsec angular resolution. We present here a computer package for simulating foreground maps for the planned sub-mm and far-IR missions. such as SPECS. The package allows to study confusion limits and simulate cosmological observations for specified sky location interactively and in real time. Most of the emission at wavelengths long-ward of approximately 50 microns is dominated by Galactic cirrus and Zodiacal dust emission. Stellar emission at these wavelengths is weak and is for now neglected. Cosmological sources (distant and not-so-distant) galaxies for specified cosmologies will be added. Briefly, the steps that the algorithm goes through is described.

  6. Digital Frequency Domain Multiplexer for mm-Wavelength Telescopes

    SciTech Connect

    Spieler, Helmuth G; Dobbs, Matt; Bissonnette, Eric; Spieler, Helmuth G.

    2007-07-23

    An FPGA based digital signal processing (DSP) system for biasing and reading out multiplexed bolometric detectors for mm-wavelength telescopes is presented. This readout system is being deployed for balloon-borne and ground based cosmology experiments with the primary goal of measuring the signature of inflation with the Cosmic Microwave Background Radiation. The system consists of analog superconducting electronics running at 250 mK and 4 K, coupled to digital room temperature backend electronics described here. The digital electronics perform the real time functionality with DSP algorithms implemented in firmware. A soft embedded processor provides all of the slow housekeeping control and communications. Each board in the system synthesizes multi-frequency combs of 8 to 32 carriers in the MHz band to bias the detectors. After the carriers have been modulated with the sky-signal by the detectors, the same boards digitize the comb directly. The carriers are mixed down to base-band and low pass filtered. The signal bandwidth of 0.050Hz-100 Hz places extreme requirements on stability and requires powerful filtering techniques to recover the sky-signal from the MHz carriers.

  7. Parallel implementation, validation, and performance of MM5

    SciTech Connect

    Michalakes, J.; Canfield, T.; Nanjundiah, R.; Hammond, S.; Grell, G.

    1994-12-31

    We describe a parallel implementation of the nonhydrostatic version of the Penn State/NCAR Mesoscale Model, MM5, that includes nesting capabilities. This version of the model can run on many different massively Parallel computers (including a cluster of workstations). The model has been implemented and run on the IBM SP and Intel multiprocessors using a columnwise decomposition that supports irregularly shaped allocations of the problem to processors. This stategy will facilitate dynamic load balancing for improved parallel efficiency and promotes a modular design that simplifies the nesting problem AU data communication for finite differencing, inter-domain exchange of data, and I/O is encapsulated within a parallel library, RSL. Hence, there are no sends or receives in the parallel model itself. The library is Generalizable to other, similar finite difference approximation codes. The code is validated by comparing the rate of growth in error between the sequential and parallel models with the error growth rate when the sequential model input is perturbed to simulate floating point rounding error. Series of runs on increasing numbers of parallel processors demonstrate that the parallel implementation is efficient and scalable to large numbers of processors.

  8. Manufacturing and performance test of an 800-mm space optic

    NASA Astrophysics Data System (ADS)

    Krödel, Matthias R.; Ozaki, Tsuyoshi; Kume, Masami; Furuya, Akira; Yui, Yukari Y.; Imai, Hiroko; Katayama, Haruyoshi; Tange, Yoshio; Nakagawa, Takao; Kaneda, Hidehiro

    2008-07-01

    Next generation space telescopes, which are currently being developed in the US and Europe, require large-scale light-weight reflectors with high specific strength, high specific stiffness, low CTE, and high thermal conductivity. To meet budget constraints, they also require materials that produce surfaces suitable for polishing without expensive over-coatings. HB-Cesic - a European and Japanese trademark of ECM - is a Hybrid Carbon-Fiber Reinforced SiC composite developed jointly by ECM and MELCO to meet these challenges. The material's mechanical performance, such as stiffness, bending strength, and fracture toughness are significantly improved compared to the classic ECM Cesic material (type MF). Thermal expansion and thermal conductivity of HB-Cesic at cryogenic temperatures are now partly established; and excellent performance for large future space mirrors and structures are expected. This paper presents the design and manufacturing of an 800-mm mirror for space application, starting with the C/C raw material preparation to the finishing of the components, including the polishing of the mirror. The letters "HB" in HB-Cesic stand for "hybrid" to indicate that the C/C raw material is composed of a mixture of different types of chopped, short carbon-fibers.

  9. Kinetic Inductance Detectors development for mm-wave Astronomy

    NASA Astrophysics Data System (ADS)

    Monfardini, A.; Swenson, L. J.; Benoit, A.; Bideau, A.; Bres, G.; Camus, P.; Garde, G.; Hoffmann, C.; Minet, J.; Rodenas, H.; Nika Collaboration

    Throughout the last decades, development of low-temperat- ure detectors focused mainly on the design of high-sensitivity, single-pixel devices. This includes such devices as semiconductor-based photodetectors and bolometers, Magnetic Metallic Calorimeters (MMC), Superconducting Tunnel Junctions (STJ), and Transition Edge Sensors (TES). However, these devices have had limited success in achieving the simultaneous large-scale array sizes and large-bandwidth operation necessary for high-speed, high-resolution detection. To overcome this performance limitation, it is advisable to focus on low-temperature detectors which are intrinsically adapted to giant-array multiplexing and ultra-fast readout. To adopt large scale frequency-domain multiplexing for low-temperature detectors, it is necessary to find detectors which"broadcast" at microwave frequencies. Superconducting microwave resonators naturally lend themselves to this task. One recent demonstration is an implementation known as Kinetic Inductance Detectors (KIDs). This detection mechanism can be adopted for low-energy EM radiation (radio, mm, THz) in continuous mode, or in pulsed mode for higher energy radiation and particles. We present an ongoing development for a KIDs instrument dedicated to millimetric ground-based observations at the 30m IRAM telescope at Pico Veleta. The Neel IRAM KIDs Array (NIKA) project is coordinated in Grenoble and involves groups in Holland (SRON), UK (Cardiff) and Italy (Roma).

  10. The influence of calcium and pH on growth in primary roots of Zea mays

    NASA Technical Reports Server (NTRS)

    Hasenstein, K. H.; Evans, M. L.

    1988-01-01

    We investigated the interaction of Ca2+ and pH on root elongation in Zea mays L. cv. B73 x Missouri 17 and cv. Merit. Seedlings were raised to contain high levels of Ca2+ (HC, imbibed and raised in 10 mM CaCl2) or low levels of Ca2+ (LC, imbibed and raised in distilled water). In HC roots, lowering the pH (5 mM MES/Tris) from 6.5 to 4.5 resulted in strong, long-lasting growth promotion. Surprisingly, increasing the pH from 6.5 to 8.5 also resulted in strong growth promotion. In LC roots acidification of the medium (pH 6.5 to 4.5) resulted in transient growth stimulation followed by a gradual decline in the growth rate toward zero. Exposure of LC roots to high pH (pH shift from 6.5 to 8.5) also promoted growth. Addition of EGTA resulted in strong growth promotion in both LC and HC roots. The ability of EGTA to stimulate growth appeared not to be related to H+ release from EGTA upon Ca2+ chelation since, 1) LC roots showed a strong and prolonged response to EGTA, but only a transient response to acid pH, and 2) promotion of growth by EGTA was observed in strongly buffered solutions. We also examined the pH dependence of the release of 45Ca2+ from roots of 3-day-old seedlings grown from grains imbibed in 45Ca2+. Release of 45Ca2+ from the root into agar blocks placed on the root surface was greater the more acidic the pH of the blocks. The results indicate that Ca2+ may be necessary for the acid growth response in roots.

  11. Experimentally and theoretically observed native pH shifts in a nanochannel array

    PubMed Central

    Bottenus, Danny; Oh, Youn-Jin; Han, Sang M.; Ivory, Cornelius F.

    2010-01-01

    Lab-on-a-chip (LOC) technology provides a powerful platform for simultaneous separation, purification, and identification of low concentration multicomponent mixtures. As the characteristic dimension of LOC devices decreases down to the nanoscale, the possibility of containing an entire lab on a single chip is becoming a reality. This research examines one of the unique physical characteristics of nanochannels, in which native pH shifts occur. As a result of the electrical double layer taking up a significant portion of a 100 nm wide nanochannel, electroneutrality no longer exists in the channel causing a radial pH gradient. This work describes experimentally observed pH shifts as a function of ionic strength using the fluorescent pH indicator 5-(and-6)-carboxy SNARF®-1 and compares it to a model developed using Comsol Multiphysics. At low ionic strengths (~ 3 mM) the mean pH shift is approximately 1 pH unit whereas at high ionic strengths (~ 150 mM) the mean pH shift is reduced to 0.1 pH units. An independent analysis using fluorescein pH indicator is also presented supporting these findings. Two independent non-linear simulations coupling the Nernst-Planck equation describing transport in ionic solutions subjected to an electric field and Poisson's equation to describe the electric field as it relates to the charge distribution are solved using a finite element solver. In addition, the effects of chemical activities are considered in the simulations. The first numerical simulation is based on a surface ζ-potential which significantly underestimates the experimental results for most ionic strengths. A modified model assuming that SNARF and fluorescein molecules are able to diffuse into the hydrolyzed SiO2 phase, and in the case of the SNARF molecule, able to bind to neutral regions of the SiO2 phase agrees quantitatively with experimental results. PMID:19107277

  12. DNA synthesis and microtubule assembly-related events in fertilized Paracentrotus lividus eggs: reversible inhibition by 10 mM procaine.

    PubMed

    Raymond, M N; Foucault, G; Coffe, G; Pudles, J

    1986-04-01

    This report describes the effects of 10 mM procaine on microtubule assembly and on DNA synthesis, as followed by [3H]colchicine binding assays and [3H]thymidine incorporation respectively, in fertilized Paracentrotus lividus eggs. In the absence of microtubule assembly inhibitors, about 25% of the total egg tubulin is submitted to two cycles of polymerization prior to the first cell division, this polymerization process precedes DNA synthesis. If the zygotes are treated with 10 mM procaine in the course of the cell cycle, tubulin polymerization is inhibited or microtubules are disassembled. DNA synthesis is inhibited when procaine treatment is performed 10 min, before the initiation of the S-period. However, when the drug is applied in the course of this synthetic period, the process is normally accomplished, but the next S-period becomes inhibited. Moreover, procaine treatment increases the cytoplasmic pH of the fertilized eggs by about 0.6 to 0.8 pH units. This pH increase precedes microtubule disassembly and inhibition of DNA synthesis. Washing out the drug induces a decrease of the intracellular pH which returns to about the same value as that of the fertilized egg controls. This pH change is then followed by the reinitiation of microtubule assembly, DNA synthesis and cell division. Our results show that the inhibition of both tubulin polymerization and DNA synthesis in fertilized eggs treated with 10 mM procaine, appears to be related to the drug-induced increase in cytoplasmic pH. PMID:3709552

  13. Influence of five neutralizing products on intra-oral pH after rinsing with simulated gastric acid.

    PubMed

    Lindquist, Birgitta; Lingström, Peter; Fändriks, Lars; Birkhed, Dowen

    2011-08-01

    The aetiology of dental erosion may be of both extrinsic and intrinsic origin. The aim of the present study was to test the ability of various neutralizing products to raise the low intra-oral pH after an erosive exposure, in this case to gastric acid, which was simulated using hydrochloric acid (HCl). Eleven adults participated. They rinsed with 10 ml of 10 mM HCl (pH 2) or 10 ml of 100 mM HCl (pH 1) for 1 min, after which the pH was measured intra-orally for up to 30 min at four sites (two approximal, one buccal, and the dorsum of the tongue). After rinsing with the two acid solutions (pH 1 and pH 2), the following products were used: (i) antacid tablet; (ii) gum arabic lozenge; (iii) mineral water; (iv) milk; and (v) tap water (positive control). The negative control was no product use. The five test products were used for 2 min after the erosive challenge. All the products produced an initially higher pH compared with the negative control. The antacid tablet resulted in the greatest and most rapid increase in pH, followed by the lozenge. In dental practice, the use of any of the neutralizing products tested, especially the antacid tablet, could be recommended in order to increase the intra-oral pH after an erosive challenge. PMID:21726291

  14. Stabilization of pH in solid-matrix hydroponic systems

    NASA Technical Reports Server (NTRS)

    Frick, J.; Mitchell, C. A.

    1993-01-01

    2-[N-morpholino]ethanesulfonic acid (MES) buffer or Amberlite DP-1 (cation-exchange resin beads) were used to stabilize substrate pH of passive-wicking, solid-matrix hydroponic systems in which small canopies of Brassica napus L. (CrGC 5-2, genome : ACaacc) were grown to maturity. Two concentrations of MES (5 or 10 mM) were included in Hoagland 1 nutrient solution. Alternatively, resin beads were incorporated into the 2 vermiculite : 1 perlite (v/v) growth medium at 6% or 12% of total substrate volume. Both strategies stabilized pH without toxic side effects on plants. Average seed yield rates for all four pH stabilization treatments (13.3 to 16.9 g m-2 day-1) were about double that of the control (8.2 g m-2 day-1), for which there was no attempt to buffer substrate pH. Both the highest canopy seed yield rate (16.9 g m-2 day-1) and the highest shoot harvest index (19.5%) occurred with the 6% resin bead treatment, even though the 10 mM MES and 12% bead treatments maintained pH within the narrowest limits. The pH stabilization methods tested did not significantly affect seed oil and protein contents.

  15. Stabilization of pH in solid-matrix hydroponic systems.

    PubMed

    Frick, J; Mitchell, C A

    1993-10-01

    2-[N-morpholino]ethanesulfonic acid (MES) buffer or Amberlite DP-1 (cation-exchange resin beads) were used to stabilize substrate pH of passive-wicking, solid-matrix hydroponic systems in which small canopies of Brassica napus L. (CrGC 5-2, genome : ACaacc) were grown to maturity. Two concentrations of MES (5 or 10 mM) were included in Hoagland 1 nutrient solution. Alternatively, resin beads were incorporated into the 2 vermiculite : 1 perlite (v/v) growth medium at 6% or 12% of total substrate volume. Both strategies stabilized pH without toxic side effects on plants. Average seed yield rates for all four pH stabilization treatments (13.3 to 16.9 g m-2 day-1) were about double that of the control (8.2 g m-2 day-1), for which there was no attempt to buffer substrate pH. Both the highest canopy seed yield rate (16.9 g m-2 day-1) and the highest shoot harvest index (19.5%) occurred with the 6% resin bead treatment, even though the 10 mM MES and 12% bead treatments maintained pH within the narrowest limits. The pH stabilization methods tested did not significantly affect seed oil and protein contents. PMID:11537992

  16. Management of anterior caliceal stones >15 mm.

    PubMed

    El-Shazly, M; Aziz, M; Omar, M; Al-Hunaidi, O; El-Nahas, A R

    2016-08-01

    Anterior caliceal stones represent a challenge to endourologist to select the best modality of management with the least morbidity. To study different treatment modalities of management of anterior caliceal stones >15 mm. It is an observational prospective study of patients with anterior caliceal stones more than 15 mm. Inclusion criteria were patients with isolated anterior caliceal stones, or branched anterior caliceal stones with posterior caliceal extension. Patients were evaluated using non-contrast CT preoperatively. They were divided into three groups: group 1 underwent PCNL through posterior caliceal puncture in cases with wide anterior calyx infundibulum or obtuse infundibulopelvic pelvic, group 2 underwent PCNL through anterior caliceal access in cases with narrow infundibulum or acute infundibulopelvic angel and group 3 underwent flexible ureteroscopy and laser lithotripsy. Intraoperative and postoperative findings were recorded and compared. Eighty eight patients were included in this study, Group 1 (44 patients) group 2 (28 patients), and group 3 (16 patients). Operative time was not significantly different across the three groups (68 ± 11.5, 72 ± 9 and 74 ± 11 min in group 1, 2 and 3, respectively, P = 0.053). Fluoroscopy time was significantly shorter for group 3 (2 ± 0.5 m, P = 0.0001) compared to group 1 and 2 (5.6 ± 4.6 and 4.5 ± 1.4 min), respectively. There were no significant differences in stone-free rates after initial treatment between the three groups; 84, 82, and 69 %, in groups 1, 2 and 3, respectively (P = 0.4). Postoperative hemoglobin drop was noted to be highest for group 2 and lowest for group 3 which was significantly different (1.7 ± 0.8, 2.2 ± 1.1, and 0.3 ± 0.3 g/dl, for patients in groups 1, 2 and 3 respectively, P = 0.0001). Group 2 showed the highest post-operative complication rate (21 %) in comparison to group 1 (11 %) and group 3 (6 %), however, differences were not statistically

  17. pH Meter probe assembly

    DOEpatents

    Hale, Charles J.

    1983-01-01

    An assembly for mounting a pH probe in a flowing solution, such as a sanitary sewer line, which prevents the sensitive glass portion of the probe from becoming coated with grease, oil, and other contaminants, whereby the probe gives reliable pH indication over an extended period of time. The pH probe assembly utilizes a special filter media and a timed back-rinse feature for flushing clear surface contaminants of the filter. The flushing liquid is of a known pH and is utilized to check performance of the probe.

  18. pH Meter probe assembly

    DOEpatents

    Hale, C.J.

    1983-11-15

    An assembly for mounting a pH probe in a flowing solution, such as a sanitary sewer line, which prevents the sensitive glass portion of the probe from becoming coated with grease, oil, and other contaminants, whereby the probe gives reliable pH indication over an extended period of time. The pH probe assembly utilizes a special filter media and a timed back-rinse feature for flushing clear surface contaminants of the filter. The flushing liquid is of a known pH and is utilized to check performance of the probe. 1 fig.

  19. Dosimetric study of the 15 mm ROPES eye plaque.

    PubMed

    Granero, D; Pérez-Calatayud, J; Ballester, F; Casal, E; de Frutos, J M

    2004-12-01

    The main aim of this paper is to make a study of dose-rate distributions obtained around the 15 mm, radiation oncology physics and engineering services, Australia (ROPES) eye plaque loaded with 125I model 6711 radioactive seeds. In this study, we have carried out a comparison of the dose-rate distributions obtained by the algorithm used by the Plaque Simulator (PS) (BEBIG GmbH, Berlin, Germany) treatment planning system with those obtained by means of the Monte Carlo method for the ROPES eye plaque. A simple method to obtain the dose-rate distributions in a treatment planning system via the superposition of the dose-rate distributions of a seed placed in the eye plaque has been developed. The method uses eye plaque located in a simplified geometry of the head anatomy and distributions obtained by means of the Monte Carlo code GEANT4. The favorable results obtained in the development of this method suggest that it could be implemented on a treatment planning system to improve dose-rate calculations. We have also found that the dose-rate falls sharply along the eye and that outside the eye the dose-rate is very low. Furthermore, the lack of backscatter photons from the air located outside the eye-head phantom produces a dose reduction negligible for distances from the eye-plaque r<1 cm but reaches up to 20% near the air-eye interface. Results showed that the treatment planning system lacks accuracy around the border of the eye (in the sclera and the surrounding area) due to the simplicity of the algorithm used. The BEBIG treatment planning system uses a global attenuation factor that takes into account the effect of the eye plaque seed carrier and the lack of backscatter photons caused by the metallic cover, which in the case of a ROPES eye plaque has a default value of T= 1 (no correction). In the present study, a global attenuation factor T=0.96 and an air-interface correction factor which improve on treatment planning system calculations were obtained. PMID

  20. Dosimetric study of the 15 mm ROPES eye plaque

    SciTech Connect

    Granero, D.; Perez-Calatayud, J.; Ballester, F.; Casal, E.; Frutos, J.M. de

    2004-12-01

    The main aim of this paper is to make a study of dose-rate distributions obtained around the 15 mm, radiation oncology physics and engineering services, Australia (ROPES) eye plaque loaded with {sup 125}I model 6711 radioactive seeds. In this study, we have carried out a comparison of the dose-rate distributions obtained by the algorithm used by the Plaque Simulator (PS) (BEBIG GmbH, Berlin, Germany) treatment planning system with those obtained by means of the Monte Carlo method for the ROPES eye plaque. A simple method to obtain the dose-rate distributions in a treatment planning system via the superposition of the dose-rate distributions of a seed placed in the eye plaque has been developed. The method uses eye plaque located in a simplified geometry of the head anatomy and distributions obtained by means of the Monte Carlo code GEANT4. The favorable results obtained in the development of this method suggest that it could be implemented on a treatment planning system to improve dose-rate calculations. We have also found that the dose-rate falls sharply along the eye and that outside the eye the dose-rate is very low. Furthermore, the lack of backscatter photons from the air located outside the eye-head phantom produces a dose reduction negligible for distances from the eye-plaque r<1 cm but reaches up to 20% near the air-eye interface. Results showed that the treatment planning system lacks accuracy around the border of the eye (in the sclera and the surrounding area) due to the simplicity of the algorithm used. The BEBIG treatment planning system uses a global attenuation factor that takes into account the effect of the eye plaque seed carrier and the lack of backscatter photons caused by the metallic cover, which in the case of a ROPES eye plaque has a default value of T=1 (no correction). In the present study, a global attenuation factor T=0.96 and an air-interface correction factor which improve on treatment planning system calculations were obtained.

  1. A comparable study of clinical and optical outcomes after 1.8, 2.0 mm microcoaxial and 3.0 mm coaxial cataract surgery

    PubMed Central

    Yu, Yi-Bo; Zhu, Ya-Nan; Wang, Wei; Zhang, Yi-Dong; Yu, Yin-Hui; Yao, Ke

    2016-01-01

    AIM To evaluate the clinical and optical outcomes after clear corneal incision cataract surgery (CICS) with three different incision sizes (1.8, 2.0 and 3.0 mm). METHODS Eyes of 150 patients with age-related cataract scheduled for coaxial cataract surgery were randomized to three groups: 1.8, 2.0, or 3.0 mm CICS. Intraoperative data and postoperative outcomes including surgically induced astigmatism (SIA), the corneal incision thickness, wavefront aberrations and modulation transfer function (MTF) of cornea were obtained. RESULTS There were no significant differences among the three groups in demographic characteristics and intraoperative outcome. The 1.8 and 2.0 mm microincisions showed more satisfactory clinical outcomes than the 3.0 mm incision. The 1.8 mm incision showed significantly less SIA than the 2.0 mm incision until postoperative 1mo (P<0.05), but the difference was only 0.14-0.18 D. Combined with less increased incision thickness only at postoperative 1d (P=0.013), the 1.8 mm incision presented better uncorrected distance visual acuity (UCDVA) than the 2.0 mm incision only at 1d postoperatively (P=0.008). For higher-order aberrations and other Zernike coefficients, there were no significant differences between the 1.8 mm group and 2.0 mm group (P>0.05). CONCLUSION Converting from 3.0 mm CICS to 1.8 or 2.0 mm CICS result in better clinical and optical outcomes. However, when incision is 1.8 mm, the benefits from further reduction in size compared with 2.0 mm are limited. The necessity to reduce the incision size is to be deliberated. PMID:27158610

  2. Hepatic urea synthesis and pH regulation. Role of CO2, HCO3-, pH and the activity of carbonic anhydrase.

    PubMed

    Häussinger, D; Gerok, W

    1985-10-15

    In isolated perfused rat liver, urea synthesis from ammonium ions was dependent on extracellular HCO3- and CO2 concentrations when the HCO3-/CO2 ratio in the influent perfusate was constant (pH 7.4). Urea synthesis was half-maximal at HCO3- = 4 mM, CO2 = 0.19 mM and was maximal at HCO3- and CO2 concentrations above 20 mM and 0.96 mM, respectively. At physiological HCO3- (25 mM) and CO2 (1.2 mM) concentrations in the influent perfusate, acetazolamide, the inhibitor of carbonic anhydrase, inhibited urea synthesis from ammonium ions (1 mM) by 50-60% and led to a 70% decrease in citrulline tissue levels. Acetazolamide concentrations required for maximal inhibition of urea synthesis were 0.01-0.1 mM. At subphysiological HCO3- and CO2 concentrations, inhibition of urea synthesis by acetazolamide was increased up to 90%. Inhibition of urea synthesis by acetazolamide was fully overcome in the presence of unphysiologically high HCO3- and CO2 concentrations, indicating that the inhibitory effect of acetazolamide is due to an inhibition of carbonic-anhydrase-catalyzed HCO3- supply for carbamoyl-phosphate synthetase, which can be bypassed when the uncatalyzed intramitochondrial HCO3- formation from portal CO2 is stimulated in the presence of high portal CO2 concentrations. With respect to HCO3- supply of mitochondrial carbamoyl-phosphate synthetase, urea synthesis can be separated into a carbonic-anhydrase-dependent (sensitive to acetazolamide at 0.5 mM) and a carbonic-anhydrase-independent (insensitive to acetazolamide) portion. Carbonic-anhydrase-independent urea synthesis linearly increased with the portal 'total CO2 addition' (which was experimentally determined to be CO2 addition plus 0.036 HCO3- addition) and was independent of the perfusate pH. At a constant 'total CO2 addition', carbonic-anhydrase-dependent urea synthesis was strongly affected by perfusate pH and increased about threefold when the perfusate pH was raised from 6.9 to 7.8. It is concluded that the pH

  3. Inexpensive and Disposable pH Electrodes

    ERIC Educational Resources Information Center

    Goldcamp, Michael J.; Conklin, Alfred; Nelson, Kimberly; Marchetti, Jessica; Brashear, Ryan; Epure, Emily

    2010-01-01

    Inexpensive electrodes for the measurement of pH have been constructed using the ionophore tribenzylamine for sensing H[superscript +] concentrations. Both traditional liquid-membrane electrodes and coated-wire electrodes have been constructed and studied, and both exhibit linear, nearly Nernstian responses to changes in pH. Measurements of pH…

  4. CALCULATING THE PH OF CALCIUM CARBONATE SATURATION

    EPA Science Inventory

    Two new expressions for the pH of saturation (pH subs) were derived. One is a simplified equation developed from an aqueous carbonate equilibrium system in which correction for ionic strength was considered. The other is a more accurate quadratic formula that involves computerize...

  5. pH [Measure of Acidity].

    ERIC Educational Resources Information Center

    Henderson, Paula

    This autoinstructional program deals with the study of the pH of given substances by using litmus and hydrion papers. It is a learning activity directed toward low achievers involved in the study of biology at the secondary school level. The time suggested for the unit is 25-30 minutes (plus additional time for further pH testing). The equipment…

  6. pH. Agricultural Lesson Plans.

    ERIC Educational Resources Information Center

    Southern Illinois Univ., Carbondale. Dept. of Agricultural Education and Mechanization.

    This lesson plan is intended for use in conducting classes on the effect of pH on plant growth. Presented first are an attention step/problem statement and a series of questions and answers designed to convey general information about soil pH and its effect on plants. The following topics are among those discussed: acidity and alkalinity; the…

  7. Acid loading test (pH)

    MedlinePlus

    The acid loading test (pH) measures the ability of the kidneys to send acid to the urine when there is too much acid in the ... Urine with a pH less than 5.3 is normal. Normal value ranges may vary slightly among different laboratories. Some labs use different ...

  8. Fetal scalp pH testing

    MedlinePlus

    ... Normal pH: 7.25 to 7.35 Borderline pH: 7.20 to 7.25 The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some ...

  9. Middle School and pH?

    ERIC Educational Resources Information Center

    Herricks, Susan

    2007-01-01

    A local middle school requested that the Water Center of Advanced Materials for Purification of Water With Systems (WaterCAMPWS), a National Science Foundation Science and Technology Center, provide an introduction to pH for their seventh-grade water-based service learning class. After sorting through a multitude of information about pH, a…

  10. Determination Of Ph Including Hemoglobin Correction

    DOEpatents

    Maynard, John D.; Hendee, Shonn P.; Rohrscheib, Mark R.; Nunez, David; Alam, M. Kathleen; Franke, James E.; Kemeny, Gabor J.

    2005-09-13

    Methods and apparatuses of determining the pH of a sample. A method can comprise determining an infrared spectrum of the sample, and determining the hemoglobin concentration of the sample. The hemoglobin concentration and the infrared spectrum can then be used to determine the pH of the sample. In some embodiments, the hemoglobin concentration can be used to select an model relating infrared spectra to pH that is applicable at the determined hemoglobin concentration. In other embodiments, a model relating hemoglobin concentration and infrared spectra to pH can be used. An apparatus according to the present invention can comprise an illumination system, adapted to supply radiation to a sample; a collection system, adapted to collect radiation expressed from the sample responsive to the incident radiation; and an analysis system, adapted to relate information about the incident radiation, the expressed radiation, and the hemoglobin concentration of the sample to pH.

  11. Parameters affecting downhole pH

    SciTech Connect

    Garber, J.D.; Jangama, V.R.; Willmon, J.

    1997-09-01

    The presence of acetic and formic acids in the produced water of gas condensate wells has been known for some time by the industry. In traditional water analysis, it has been titrated and reported as alkalinity. The calculation of accurate downhole pH values requires that these ions be analyzed separately in the water and that an organic acid material balance be performed on all three phases in the separator. In this manner, it is then possible to use phase distribution coefficients involving ionic equilibrium to determine how these acids distribute themselves between phases as the pH calculation proceeds downhole. In this paper, the above method of calculation of pH and {Delta}pH is used to examine the effect that various concentrations of these acids have on the downhole pH. Various concentrations of acids are examined, and two cases are calculated in which the effect of condensate on the pH is examined.

  12. Regulation of lung surfactant secretion by intracellular pH.

    PubMed

    Chander, A

    1989-12-01

    We investigated secretion of lung surfactant phosphatidylcholine (PC) using isolated perfused rat lung preparation after labeling the lung lipids in vitro with [methyl-3H]choline. The perfusion medium was Krebs-Ringer bicarbonate buffer (pH 7.4) containing 10 mM glucose and 3% fatty acid-poor bovine serum albumin. After ventilation of lungs with air containing 5% CO2 (control) for 1 h, 0.91% +/- 0.04 (mean +/- SE, n = 6) of total lung lipid radioactivity (greater than 95% in PC) was recovered in the cell-free lavage fluid. The secretion of PC was increased with terbutaline (50 microM), 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP, 100 microM), phorbol L2-myristate 13-acetate (30 ng/ml), and ATP (1 mM), in each case by approximately 150%. Secretion of PC was also increased by 160% if the lungs were ventilated with air containing 0% CO2. The low CO2-mediated PC secretion was time and concentration dependent. The dose-response curve for 0-10% CO2 was S-shaped. The low CO2-induced increase in PC secretion could be largely reversed with diffusible weak acids (25 mM, acetate or butyrate) in the perfusion medium. An increase (70%) in secretion was also induced with 10 mM NH4Cl, suggesting a role for intracellular alkalosis. These observations suggest that intracellular alkalosis stimulates lung surfactant secretion. Alkalosis-stimulated secretion of PC was additive with that with terbutaline (5 X 10(-7) to 5 X 10(-4) M) or 10(-4) M 8-BrcAMP, suggesting that alkalosis effect was not mediated through the beta-adrenergic pathway of surfactant secretion.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2514603

  13. Control of ammonia distribution ratio across the liver cell membrane and of ureogenesis by extracellular pH.

    PubMed

    Rémésy, C; Demigné, C; Fafournoux, P

    1986-07-15

    The mechanisms involved in ammonia uptake by rat liver cells and the effects of changes in extracellular pH have been investigated in vivo and in vitro. When NH4Cl solutions were infused in the hepatic portal vein, ammonia uptake by the liver was practically quantitative up to about 1 mM in afferent blood. Ammonia transfer into hepatocytes was extremely rapid: for 2 mM ammonia in external medium, the intracellular concentration reached 5 mM within 10 s. Comparatively, [14C]methylamine influx was slower and the cell concentrations did not reach a steady-state level, probably in relation with diffusion into the acidic lysosomal compartment. Intracellular accumulation of ammonia was dependent on the delta pH across the plasma membrane: the distribution ratio (internal/external) was about 1 for an external pH of 6.8 and about 5 at pH 8. Urea synthesis was maximal at physiological pH and markedly declined at pH 7.05. This inhibition was not affected by manipulation of bicarbonate concentrations in the medium, down to 10 mM. Additional inhibition of ureogenesis by 100 microM acetazolamide was also observed, particularly at low concentrations of bicarbonate in the medium. Inhibition of ureogenesis when extracellular pH is decreased could be ascribed to a lower availability of the NH3 form. Assuming that NH3 readily equilibrates between the various compartments, the availability of free ammonia for carbamoyl-phosphate synthesis could be tightly dependent on extracellular pH. PMID:3089783

  14. Superiority of 10-mm-wide Balloon over 8-mm-wide Balloon in Papillary Dilation for Bile Duct Stones: A Matched Cohort Study

    PubMed Central

    Akiyama, Dai; Hamada, Tsuyoshi; Isayama, Hiroyuki; Nakai, Yousuke; Tsujino, Takeshi; Umefune, Gyotane; Takahara, Naminatsu; Mohri, Dai; Kogure, Hirofumi; Matsubara, Saburo; Ito, Yukiko; Yamamoto, Natsuyo; Sasahira, Naoki; Tada, Minoru; Koike, Kazuhiko

    2015-01-01

    Background/Aims: Endoscopic papillary balloon dilation (EPBD) is a possible alternative to endoscopic sphincterotomy (EST) for common bile duct (CBD) stones. To date, 10- and 8-mm EPBD have not been fully compared. Patients and Methods: Patients who underwent EPBD for CBD stones at two Japanese tertiary care centers between May 1994 and January 2014 were identified. Matched pairs with 10- and 8-mm EPBD were generated. Short- and long-term outcomes were compared between the two groups. Results: A total of 869 patients were identified (61 and 808 patients for 10- and 8-mm EPBD, respectively), and 61 well-balanced pairs were generated. The rate of complete stone removal within a single session was higher in the 10-mm EPBD group than in the 8-mm EPBD group (69% vs. 44%, P < 0.001), and use of lithotripsy was less frequent in the 10-mm EPBD group (23% vs. 56%, P < 0.001). The rates of post-ERCP pancreatitis were similar between the 10- and 8-mm EPBD groups (11% vs. 8%). Cumulative biliary complication-free rates were not statistically different between the two groups: 88% [95% confidence interval (CI): 79–97%] and 94% (95% CI: 88–100%) at 1 year and 69% (95% CI: 56–85%) and 80% (95% CI: 69–93%) at 2 years in the 10- and 8-mm EPBD groups, respectively. In the 10-mm EPBD group, ascending cholangitis was not observed, and pneumobilia was found in 5% of cases during the follow-up period. Conclusions: EPBD using a 10-mm balloon for CBD stones is safe and more effective than 8-mm EPBD. The sphincter function is highly preserved after 10-mm EPBD. PMID:26228364

  15. Stress Analysis on Single Cobalt/Chrome Prosthesis With a 15-mm Cantilever Placed Over 10/13/15-mm-length Implants: A Simulated Photoelastic Model Study.

    PubMed

    Gastaldo, José Fábio Guastelli; Pimentel, Angélica Castro; Gomes, Maria Helena; Sendyk, Wilson Roberto; Laganá, Dalva Cruz

    2015-12-01

    The aim of study was to assess the stress around 10/13/15-mm implants in the mandibular area with a 15-mm cantilevered acrylic-resin-coated prostheses following the application force, using the photoelasticity method. Three photoelastic mandibular models were created containing 10-, 13-, and 15-mm implants in length and 3.75 mm in diameter. The implants had bore internal hex connections and were placed parallel to the intermental region. Abutments with 1-mm high cuffs were placed over the implants, and a single cobalt/chrome metallic prosthesis with a 15-mm cantilever, coated with thermoplastic acrylic resin, was placed on top. Loads of 1.0 and 3.0 bars were applied, and the images were photographed and assessed by photoelasticity method. The greatest stress levels were observed for the 10-mm implants. The stress pattern was the same regardless of implant length; only the magnitude of the stress along the implant body revealed changes. Increased implant length played a role in reducing stress on the investigated area of the model, and the 15-mm implants exhibited the best performance in regard to stress distribution. The highest stress levels were found in the implants closest to the cantilever and the central implant. The longest implants were more favorable in regard to the stress distribution on the peri-implant support structures in the 15-mm cantilevered prosthesis under loads. PMID:24914673

  16. BCL-B (BCL2L10) is overexpressed in patients suffering from multiple myeloma (MM) and drives an MM-like disease in transgenic mice.

    PubMed

    Hamouda, Mohamed-Amine; Jacquel, Arnaud; Robert, Guillaume; Puissant, Alexandre; Richez, Valentine; Cassel, Romeo; Fenouille, Nina; Roulland, Sandrine; Gilleron, Jerome; Griessinger, Emmanuel; Dubois, Alix; Bailly-Maitre, Beatrice; Goncalves, Diogo; Mallavialle, Aude; Colosetti, Pascal; Marchetti, Sandrine; Amiot, Martine; Gomez-Bougie, Patricia; Rochet, Nathalie; Deckert, Marcel; Avet-Loiseau, Herve; Hofman, Paul; Karsenti, Jean-Michel; Jeandel, Pierre-Yves; Blin-Wakkach, Claudine; Nadel, Bertrand; Cluzeau, Thomas; Anderson, Kenneth C; Fuzibet, Jean-Gabriel; Auberger, Patrick; Luciano, Frederic

    2016-08-22

    Multiple myeloma (MM) evolves from a premalignant condition known as monoclonal gammopathy of undetermined significance (MGUS). However, the factors underlying the malignant transformation of plasmocytes in MM are not fully characterized. We report here that Eµ-directed expression of the antiapoptotic Bcl-B protein in mice drives an MM phenotype that reproduces accurately the human disease. Indeed, with age, Eµ-bcl-b transgenic mice develop the characteristic features of human MM, including bone malignant plasma cell infiltration, a monoclonal immunoglobulin peak, immunoglobulin deposit in renal tubules, and highly characteristic bone lytic lesions. In addition, the tumors are serially transplantable in irradiated wild-type mice, underlying the tumoral origin of the disease. Eµ-bcl-b plasmocytes show increased expression of a panel of genes known to be dysregulated in human MM pathogenesis. Treatment of Eµ-bcl-b mice with drugs currently used to treat patients such as melphalan and VELCADE efficiently kills malignant plasmocytes in vivo. Finally, we find that Bcl-B is overexpressed in plasmocytes from MM patients but neither in MGUS patients nor in healthy individuals, suggesting that Bcl-B may drive MM. These findings suggest that Bcl-B could be an important factor in MM disease and pinpoint Eµ-bcl-b mice as a pertinent model to validate new therapies in MM. PMID:27455953

  17. Formation of Hg(II) Tetrathiolate Complexes with Cysteine at Neutral pH

    PubMed Central

    Warner, Thomas; Jalilehvand, Farideh

    2015-01-01

    Mercury(II) ions precipitate from aqueous cysteine (H2Cys) solutions containing H2Cys/Hg(II) mole ratio ≥ 2.0 as Hg(S-HCys)2. In absence of additional cysteine, the precipitate dissolves at pH ~12 with the [Hg(S,N-Cys)2]2− complex dominating. With excess cysteine (H2Cys/Hg(II) mole ratio ≥ 4.0), higher complexes form and the precipitate dissolves at lower pH values. Previously, we found that tetrathiolate [Hg(S-Cys)4]6− complexes form at pH = 11.0; in this work we extend the investigation to pH values of physiological interest. We examined two series of Hg(II)-cysteine solutions in which CHg(II) varied between 8 – 9 mM and 80 – 100 mM, respectively, with H2Cys/Hg(II) mole ratios from 4 to ~20. The solutions were prepared in the pH range 7.1 – 8.8, at the pH at which the initial Hg(S-HCys)2 precipitate dissolved. The variations in the Hg(II) speciation were followed by 199Hg NMR, X-ray absorption and Raman spectroscopic techniques. Our results show that in the dilute solutions (CHg(II) = 8 – 9 mM), mixtures of di-, tri- (major) and tetrathiolate complexes exist at moderate cysteine excess (CH2Cys ~ 0.16 M) at pH 7.1. In the more concentrated solutions (CHg(II) = 80 – 100 mM) with high cysteine excess (CH2Cys > 0.9 M), tetrathiolate [Hg(S-cysteinate)4]m-6 (m = 0 – 4) complexes dominate in the pH range 7.3 – 7.8, with lower charge than for the [Hg(S-Cys)4]6− complex due to protonation of some (m) of the amino groups of the coordinated cysteine ligands. The results of this investigation could provide a key to the mechanism of biosorption and accumulation of Hg(II) ions in biological / environmental systems. PMID:27064521

  18. Effect of pH, salt, and biopolymer ratio on the formation of pea protein isolate-gum arabic complexes.

    PubMed

    Liu, Shuanghui; Low, Nicholas H; Nickerson, Michael T

    2009-02-25

    Turbidity measurements were used to study the formation of soluble and insoluble complexes between pea protein isolate (PPI) and gum arabic (GA) mixtures as a function of pH (6.0-1.5), salt concentration (NaCl, 0-50 mM), and protein-polysaccharide weight mixing ratio (1:4 to 10:1 w/w). For mixtures in the absence of salt and at a 1:1 mixing ratio, two structure-forming transitions were observed as a function of pH. The first event occurred at a pH of 4.2, with the second at pH 3.7, indicating the formation of soluble and insoluble complexes, respectively. Sodium chloride (mM) was found to have no effect on biopolymer interactions, but interfered with interactions at higher levels (>7.5 mM) due to substantial PPI aggregation. The pH at which maximum PPI-GA interactions occurred was 3.5 and was independent of NaCl levels. As PPI-GA ratios increased, structure-forming transitions shifted to higher pH. PMID:19170635

  19. Comparison of Surgically-induced Astigmatism after Combined Phacoemulsification and 23-Gauge Vitrectomy: 2.2-mm vs. 2.75-mm Cataract Surgery

    PubMed Central

    Kim, Yong-Kyu; Kim, Yong Woo; Park, Kyu Hyung

    2014-01-01

    Purpose The 2.2-mm microincision cataract surgery and small-gauge vitrectomy system is known to result in less surgically-induced astigmatism (SIA) in comparison to conventional surgical methods. We compared the amounts of SIA after combined phacoemulsification and 23-gauge transconjunctival sutureless vitrectomy (23G-TSV) using the 2.2-mm microincision and 2.75-mm standard incision methods. Methods We studied 59 patients (61 eyes) who underwent combined phacoemulsification and 23G-TSV from November 2008 to September 2012. Twenty-eight patients (28 eyes) underwent 2.2-mm microincision coaxial phacoemulsification, and 31 patients (33 eyes) underwent 2.75-mm standard incision phacoemulsification. SIA was evaluated using Naeser's polar method with the simulated keratometric values obtained from corneal topography. Preoperative and 1-week and 1-month postoperative KP (Naeser's polar value along the specific axis) and ΔKP values were compared between the 2.2-mm microincision and 2.75-mm standard incision groups. Results One week after surgery, both groups exhibited similar amounts of SIA (-ΔKP[120], 0.40 ± 0.41 vs. 0.51 ± 0.56 diopters [D]; p = 0.390). One month after surgery, however, the amount of SIA was significantly smaller in the 2.2-mm microincision group as compared to the 2.75-mm standard incision group (-ΔKP[120], 0.31 ± 0.54 vs. 0.56 ± 0.42 D; p = 0.045). Conclusions In combined phacoemulsification with 23G-TSV, 2.2-mm microincision coaxial phacoemulsification induces less SIA than does 2.75-mm standard coaxial phacoemulsification. PMID:24688255

  20. Colorimetric Determination of pH.

    ERIC Educational Resources Information Center

    Tucker, Sheryl; And Others

    1989-01-01

    Presented is an activity in which the pH of a solution can be quantitatively measured using a spectrophotometer. The theory, experimental details, sample preparation and selection, instrumentation, and results are discussed. (CW)

  1. Brenda K. Edwards, PhD

    Cancer.gov

    Brenda K. Edwards, PhD, has been with the Surveillance Research Program (SRP) and its predecessor organizations at the National Cancer Institute (NCI) since 1989, serving as SRP’s Associate Director from 1990-2011.

  2. Catalytic Mechanism of RNA Backbone Cleavage by Ribonuclease H from QM/MM Simulations

    PubMed Central

    Rosta, Edina; Nowotny, Marcin; Yang, Wei; Hummer, Gerhard

    2011-01-01

    We use quantum mechanics/molecular mechanics (QM/MM) simulations to study the cleavage of the ribonucleic acid (RNA) backbone catalyzed by ribonuclease H. This protein is a prototypical member of a large family of enzymes that use two-metal catalysis to process nucleic acids. By combining Hamiltonian replica exchange with a finite-temperature string method, we calculate the free energy surface underlying the RNA cleavage reaction and characterize its mechanism. We find that the reaction proceeds in two steps. In a first step, catalyzed primarily by magnesium ion A and its ligands, a water molecule attacks the scissile phosphate. Consistent with thiol-substitution experiments, a water proton is transferred to the downstream phosphate group. The transient phosphorane formed as a result of this nucleophilic attack decays by breaking the bond between the phosphate and the ribose oxygen. In the resulting intermediate, the dissociated but unprotonated leaving group forms an alkoxide coordinated to magnesium ion B. In a second step, the reaction is completed by protonation of the leaving group, with a neutral Asp132 as a likely proton donor. The overall reaction barrier of ~15 kcal mol−1, encountered in the first step, together with the cost of protonating Asp132, is consistent with the slow measured rate of ~1–100/min. The two-step mechanism is also consistent with the bell-shaped pH dependence of the reaction rate. The non-monotonic relative motion of the magnesium ions along the reaction pathway agrees with X-ray crystal structures. Proton transfer reactions and changes in the metal ion coordination emerge as central factors in the RNA cleavage reaction. PMID:21539371

  3. Feasibility of converting hi-speed processor for processing Kodak film types 7381/7271 (16mm) and 5381/5271 (35mm) using Kodak ECP chemistry

    NASA Technical Reports Server (NTRS)

    Weinstein, M. S.

    1974-01-01

    Testing conducted to determine the feasibility of converting the 16/35/70 hi-speed processor to process Kodak film types 7381/7271 (16mm) and 5381/5271 (35mm) color negative films using Kodak ECP chemistry is described.

  4. Feature Films on 8mm and 16 mm. A Directory of Feature Films Available for Rental, Sale, and Lease in the United States.

    ERIC Educational Resources Information Center

    Limbacher, James L., Comp.

    Compiled from distributors' catalogs and supplementary lists, this third edition of the directory lists more than 10,000 feature films on 8mm and 16mm which are available for rental, sale, or lease. For this directory, a feature film is defined as one which runs more than 45 minutes or is longer than one reel. The films are listed in alphabetical…

  5. Microchamber arrays with an integrated long luminescence lifetime pH sensor.

    PubMed

    Poehler, Elisabeth; Pfeiffer, Simon A; Herm, Marc; Gaebler, Michael; Busse, Benedikt; Nagl, Stefan

    2016-04-01

    A pH probe with a microsecond luminescence lifetime was obtained via covalent coupling of 6-carboxynaphthofluorescein (CNF) moieties to ruthenium-tris-(1,10-phenanthroline)(2+). The probe was covalently attached to amino-modified poly-(2-hydroxyethyl)methacrylate (pHEMA) and showed a pH-dependent FRET with luminescence lifetimes of 681 to 1260 ns and a working range from ca. pH 6.5 to 9.0 with a pKa of 7.79 ± 0.14. The pH sensor matrix was integrated via spin coating as ca. 1- to 2-μm-thick layer into "CytoCapture" cell culture dishes of 6 mm in diameter. These contained a microcavity array of square-shaped regions of 40 μm length and width and 15 μm depth that was homogeneously coated with the pH sensor matrix. The sensor layer showed fast response times in both directions. A microscopic setup was developed that enabled imaging of the pH inside the microchamber arrays over many hours. As a proof of principle, we monitored the pH of Escherichia coli cell cultures grown in the microchamber arrays. The integrated sensor matrix allowed pH monitoring spatially resolved in every microchamber, and the differences in cell growth between individual chambers could be resolved and quantified. Graphical abstract A pH probe with a microsecond luminescence lifetime is described and its covalent attachment to a hydrogel matrix, integration into microchamber arrays, and use for pH monitoring in a model E. coli miniaturized cell culture. PMID:26590561

  6. In Vivo Model to Test Implanted Biosensors for Blood pH

    NASA Technical Reports Server (NTRS)

    Arnaud, Sara B.; Somps, Chris J.; Madou, Marc; Hines, John; Wade, Charles E. (Technical Monitor)

    1997-01-01

    Biosensors for monitoring physiologic data continuously through telemetry are available for heart rate, respiration, and temperature but not for blood pH or ions affected by hydrogen ion concentration. A telemetric biosensor for monitoring blood pH on-line could be used to identify and manage problems in fluid and electrolyte metabolism, cardiac and respiratory function during space flight and the acid-base status of patients without the need for venipuncture in patients on Earth. Critical to the development of biosensors is a method for evaluating their performance after implantation. Mature rats, prepared with jugular, cannulas for repeated blood samples, were exposed to a gas mixture containing high levels of carbon dioxide (7%) in a closed environment to induce mild respiratory acidosis. Serial blood gas and pH measurements in venous blood were compared with electrical responses from sensors implanted in the subcutaneous tissue. Animals became slightly tachypneic after exposure to excess CO2, but remained alert and active. After 5 minutes, basal blood pH decreased from 7.404 +/- 0.013 to 7.289 +/- 0.010 (p less than 0.001)and PC02 increased from 45 +/- 6 to 65 +/- 4 mm. Hg (p les than 0.001). Thereafter pH and blood gas parameters remained stable. Implanted sensors showed a decrease in millivolts (mV) which paralleled the change in pH and averaged 5-6 mV per 0.1 unit pH. Implanted sensors remained sensitive to modest changes in tissue pH for one week. A system for inducing acidosis in rats was developed to test the in vivo performance of pH biosensors. The system provides a method which is sensitive, rapid and reproducible in the same and different animals with full recovery, for testing the performance of sensors implanted in subcutaneous tissues.

  7. Oxygen and pH regulation of protein synthesis in mitochondria from Artemia franciscana embryos.

    PubMed Central

    Kwast, K E; Hand, S C

    1996-01-01

    To identify factors responsible for the down-regulation of mitochondrial biosynthetic processes during anoxia in encysted Artemia franciscana embryos, the effects of oxygen limitation and pH on protein synthesis were investigated in isolated mitochondria. At the optimal pH of 7.5, exposure of mitochondria to anoxia decreases the protein synthesis rate by 79%. Rates were suppressed by a further 10% at pH 6.8, the intracellular pH (pHi) measured under anoxia in vivo. Matrix pH, measured under identical conditions, was 8.43 +/- 0.01 at an extra-mitochondrial pH of 7.9 (mean +/- S.E.M., n = 3), 8.05 +/- 0.01 at pH 7.5, and 7.10 +/- 0.01 at pH 6.8. The matrix pH did not vary (P > or = 0.20) as a function of oxygen availability during the 1 h assays. Intramitochondrial purine nucleotides varied little as a function of pH. In contrast, after 1 h of protein synthesis under anoxia, ATP levels decreased by up to 40%, whereas AMP, ADP and GDP concentrations increased, and GTP and GMP concentrations remained relatively constant. The addition of 1 mM ATP at the onset of anoxia maintained the ATP/ADP ratio at the aerobic value, but did not stabilized the GTP/GDP ratio or rescue rates of protein synthesis. Thus, at present, we cannot eliminate the possibility that the decrease in the GTP/GDP ratio during anoxia may contribute to the suppression of protein synthesis. The effect of anoxia was reversible; the rate of protein synthesis upon reoxygenation after a 30 min bout of anoxia was comparable (P = 0.14) with the pre-anoxic rate (193 +/- 17 and 174 +/- 6 pmol of leucine per mg of protein respectively, mean +/- S.E.M., n = 3). The array of mitochondrial translation products did not differ qualitatively as a function of either oxygen availability or pH. Finally, similar pH profiles for protein synthesis were obtained with either [3H]leucine or [3H]histidine (known to use different transporters). Consequently, it is improbable that the pH-sensitivity of protein synthesis can be

  8. Ventilatory regulation of arterial H(+) (pH) during exercise.

    PubMed

    Wasserman, Karlman; Cox, Timothy A; Sietsema, Kathy E

    2014-01-01

    We hypothesized that exercise ventilation and arterial H(+) ([H(+)]a) are mutually interactive, [H(+)]a stimulating V(E) and V(E) regulating [H(+)]a increase. Fifty-five patients were studied, 10 normal and 45 with cardio-respiratory disorders. Each patient underwent cardiopulmonary exercise testing with simultaneous serial arterial blood gas and pH measurements. Subsequently, they were classified into one of 7 clinical groups: (1) normal, (2) exercise-induced hypoxemia (PaO2<50mmHg), (3) exercise-induced myocardial ischemia, (4) heart failure, (5) COPD, (6) interstitial lung disease, and (7) pulmonary vasculopathy. The average resting pHa was 7.42 or 7.43 for each group. At anaerobic (lactic acidosis) threshold (AT), [H(+)]a increased due to PaCO2 increase (+2mmHg), primarily. At peak exercise, [H(+)]a increased further due to arterial HCO3(-) decrease. In summary, [H(+)]a appears to be closely regulated at rest to AT and further to peak exercise by CO2 elimination from the venous return. No evidence was observed for over-ventilation of CO2, causing the arterial blood to become more alkaline during exercise in the patient groups studied. PMID:24369924

  9. Washout/rainout contribution in wet deposition estimated by 0.5 mm precipitation sampling/analysis

    NASA Astrophysics Data System (ADS)

    Aikawa, Masahide; Hiraki, Takatoshi

    A precipitation dataset collected on a 0.5 mm precipitation basis was studied. The parameters analyzed in this study were the pH (i.e., H + concentration), electric conductivity (EC), and SO42- and NO3- concentrations. The NO3- concentration clearly decayed with an increase of the precipitation amount, while a larger variation was observed in the SO42- concentration even when the precipitation amount increased. Assuming that the decaying NO3- concentration (0.70 μg ml -1) was the result of the rainout process, the estimates were: annual total deposition, 3252 mg m -2 yr -1; rainout process, 1092 mg m -2 yr -1; and rainout/total, 34%. The estimates for SO42- were: annual total deposition, 4687 mg m -2 yr -1; rainout process, 2096 mg m -2 yr -1; and rainout/total, 45%.

  10. Tomato responses to ammonium and nitrate nutrition under controlled root-zone pH

    NASA Technical Reports Server (NTRS)

    Peet, M. M.; Raper, C. D. Jr; Tolley, L. C.; Robarge, W. P.; Raper CD, J. r. (Principal Investigator)

    1985-01-01

    Tomato (Lycopersicon esculentum L. Mill. 'Vendor') plants were grown for 21 days in flowing solution culture with N supplied as either 1.0 mM NO3- or 1.0 mM NH4+. Acidity in the solutions was automatically maintained at pH 6.0. Accumulation and distribution of dry matter and total N and net photosynthetic rate were not affected by source of N. Thus, when rhizosphere acidity was controlled at pH 6.0 during uptake, either NO3- or NH4+ can be used efficiently by tomato. Uptake of K+ and Ca2+ were not altered by N source, but uptake of Mg2+ was reduced in NH4(+)-fed plants. This indicates that uptake of Mg2+ was regulated at least partially by ionic balance within the plant.

  11. Tomato responses to ammonium and nitrate nutrition under controlled root-zone pH.

    PubMed

    Peet, M M; Raper, C D; Tolley, L C; Robarge, W P

    1985-01-01

    Tomato (Lycopersicon esculentum L. Mill. 'Vendor') plants were grown for 21 days in flowing solution culture with N supplied as either 1.0 mM NO3- or 1.0 mM NH4+. Acidity in the solutions was automatically maintained at pH 6.0. Accumulation and distribution of dry matter and total N and net photosynthetic rate were not affected by source of N. Thus, when rhizosphere acidity was controlled at pH 6.0 during uptake, either NO3- or NH4+ can be used efficiently by tomato. Uptake of K+ and Ca2+ were not altered by N source, but uptake of Mg2+ was reduced in NH4(+)-fed plants. This indicates that uptake of Mg2+ was regulated at least partially by ionic balance within the plant. PMID:11539725

  12. A simple model for assessing ammonia emission from ammoniacal fertilisers as affected by pH and injection into soil

    NASA Astrophysics Data System (ADS)

    Nyord, T.; Schelde, K. M.; Søgaard, H. T.; Jensen, L. S.; Sommer, S. G.

    Ammonia (NH 3) volatilisation following the application of ammoniacal fertilisers and liquid manure to agricultural land is a significant source of atmospheric NH 3, which not only poses a risk to the environment, but may also result in a loss of plant available nitrogen (N). This study examined the potential for reducing NH 3 emission through acidifying an ammoniacal solution and by injecting the solution. The combination of the two technologies was studied and a model for predicting the most optimal treatment was developed. In the laboratory, ammonium (NH 4+) hydroxide (aqueous NH 3) was dissolved in water (pH 11) and injected into a loamy sand soil. The NH 3 emission was measured with a dynamic chamber technology. Injecting the solution to 10 mm below the soil surface reduced NH 3 emission by 10% compared to surface application, and injection to 30 mm reduced emission by 20% compared to surface application. Acidifying the ammoniacal solution by adding sulphuric acid and reducing pH to 10 reduced the emission by 60% at a 10 mm injection depth and 90% at 30 mm compared with non-acidified and surface-spread ammoniacal solution. The results show that there is an important interaction of pH and injection depth and that there is a need for models predicting a combined effect. This type of model could contribute to reduce cost and energy (traction force) by providing the optimal combination of acidifying and injection depth that gives a specific reduction in NH 3 emission, which in this study was reducing pH to 10 and inject the fertiliser to 30 mm below surface. This study showed that relatively simple models can predict the NH 3 emission from injected ammoniacal fertilisers, but that there is still a need for developing algorithms that predict the effect of pH, including the pH buffering capacity of the fertiliser and the soil.

  13. Kinetic evidence for the interactive inhibition of laccase from Trametes versicolor by pH and chloride.

    PubMed

    Raseda, Nasrin; Hong, Soonho; Kwon, O Yul; Ryu, Keungarp

    2014-12-28

    The interactive inhibitory effects of pH and chloride on the catalysis of laccase from Trametes versicolor were investigated by studying the alteration of inhibition characteristics of sodium chloride at different pHs for the oxidation of 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid). At pH 3.0, the addition of sodium chloride (50 mM) brought about a 40-fold increase in Km(app) and a 4-fold decrease in Vmax(app). As the pH increased to 7.0, the inhibitory effects of sodium chloride became significantly weakened. The mixed-inhibition mechanism was successfully used to quantitatively estimate the competitive and uncompetitive inhibition strengths by chloride at two different pHs (pH 3.0 and 6.0). At pH 3.0, the competitive inhibition constant, Ki, was 0.35 mM, whereas the uncompetitive inhibition constant, Ki', was 18.1 mM, indicating that the major cause of the laccase inhibition by chloride is due to the competitive inhibition step. At a higher pH of 6.0, where the inhibition of the laccase by hydroxide ions takes effect, the inhibition of the laccase by chloride diminished to a great extent, showing increased values of both the competitive inhibition constant (Ki= 23.7 mM) and uncompetitive inhibition constant (Ki' = 324 mM). These kinetic results evidenced that the hydroxide anion and chloride share a common mechanism to inhibit the laccase activity. PMID:25152059

  14. Development of luminescent pH sensor films for monitoring bacterial growth through tissue

    PubMed Central

    Wang, Fenglin; Raval, Yash; Chen, Hongyu; Tzeng, Tzuen-Rong J.; DesJardins, John D.

    2014-01-01

    Although implanted medical devices (IMDs) offer many benefits, they are susceptible to bacterial colonization and infections. Such infections are difficult to treat because bacteria could form biofilms on the implant surface, which reduce antibiotics penetration and generate local dormant regions with low pH and low oxygen. In addition, these infections are hard to detect early because biofilms are often localized on the surface. Herein, an optical sensor film is developed to detect local acidosis on an implanted surface. The film contains both upconverting particles (UCPs) that serve as a light source and a pH indicator that alters the luminescence spectrum. When irradiated with 980 nm light, the UCPs produce deeply penetrating red light emission, while generating negligible autofluorescence in the tissue. The basic form of the pH indicator absorbs more of upconversion luminescence at 661 nm than at 671 nm and consequently the spectral ratio indicates pH. Implanting this pH sensor film beneath 6-7 mm of porcine tissue does not substantially affect the calibration curve because the peaks are closely spaced. Furthermore, growth of Staphylococcus epidermidis on the sensor surface causes a local pH decrease that can be detected non-invasively through the tissue. PMID:23832869

  15. β-Galactoside-binding activity of human galectin-1 at basic pH

    NASA Astrophysics Data System (ADS)

    Hiramatsu, Hirotsugu; Takeuchi, Katsuyuki; Fukuda, Koki; Nishino, Tomohide

    2013-06-01

    β-Galactoside-binding activity of human galectin-1 (hGal-1) was evaluated at pH 7-9.5 by fluorescence spectroscopy from the fraction bound to lactose gel (Y) and the lactose binding constant (Kb). Y decreases at pH > 8.2 ± 0.1 in the absence of NaCl, while it is constant in the presence of 150 mM NaCl. On the other hand, Kb is independent of pH and the NaCl concentration at basic pH. Analysis of Raman spectrum has shown that the pKa of Cys residues of hGal-1 is 8.5 ± 0.1 on average, indicating that about 40% of the six Cys residues of hGal-1 would be deprotonated at pH 8.2. The pH dependence of Y is explained by an increase of Coulombic repulsion among negatively charged hGal-1 on the lactose gel surface. This result suggests that Y is not always a good indicator of the β-galactoside-binding activity of galectins, which contain many Cys residues.

  16. Cyclic variations in nitrogen uptake rate of soybean plants: effects of pH and mixed nitrogen sources

    NASA Technical Reports Server (NTRS)

    Raper, C. D. Jr; Vessey, J. K.; Henry, L. T.; Chaillou, S.

    1991-01-01

    To determine if the daily pattern of NO3- and NH4+ uptake is affected by acidity or NO3- : NH4+ ratio of the nutrient solution, non-nodulated soybean plants (Glycine max) were exposed for 21 days to replenished, complete nutrient solutions at pH 6.0, 5.5, 5.0, and 4.5 which contained either 1.0 mM NH4+, 1.0 mM NO3- [correction of NO3+], 0.67 mM NH4+ plus 0.33 mM NO3- (2:1 NH4+ : NO3-) [correction of (2:1 NH3+ : NO4-)], or 0.33 mM NH4+ plus 0.67 mM NO3- (1:2 NH4+ : NO3-). Net uptake rates of NH4+ and NO3- were measured daily by ion chromatography as depletion from the replenished solutions. When NH4+ and NO3- were supplied together, cumulative uptake of total nitrogen was not affected by pH or solution NH4+ : NO3- ratio. The cumulative proportion of nitrogen absorbed as NH4+ decreased with increasing acidity; however, the proportional uptake of NH4+ and NO3- was not constant, but varied day-to-day. This day-to-day variation in relative proportions of NH4+ and NO3- absorbed when NH4+ : NO3- ratio and pH of solution were constant indicates that the regulatory mechanism is not directly competitive. Regardless of the effect of pH on cumulative uptake of NH4+, the specific nitrogen uptake rates from mixed and from individual NH4+ and NO3- sources oscillated between maxima and minima at each pH with average periodicities similar to the expected interval of leaf emergence.

  17. Sub-mm Jet Properties of the X-Ray Binary Swift J1745-26

    NASA Astrophysics Data System (ADS)

    Tetarenko, A. J.; Sivakoff, G. R.; Miller-Jones, J. C. A.; Curran, P. A.; Russell, T. D.; Coulson, I. M.; Heinz, S.; Maitra, D.; Markoff, S. B.; Migliari, S.; Petitpas, G. R.; Rupen, M. P.; Rushton, A. P.; Russell, D. M.; Sarazin, C. L.

    2015-05-01

    We present the results of our observations of the early stages of the 2012-2013 outburst of the transient black hole X-ray binary (BHXRB), Swift J1745-26, with the Very Large Array, Submillimeter Array, and James Clerk Maxwell telescope (SCUBA-2). Our data mark the first multiple-band mm and sub-mm observations of a BHXRB. During our observations the system was in the hard accretion state producing a steady, compact jet. The unique combination of radio and mm/sub-mm data allows us to directly measure the spectral indices in and between the radio and mm/sub-mm regimes, including the first mm/sub-mm spectral index measured for a BHXRB. Spectral fitting revealed that both the mm (230 GHz) and sub-mm (350 GHz) measurements are consistent with extrapolations of an inverted power law from contemporaneous radio data (1-30 GHz). This indicates that, as standard jet models predict, a power law extending up to mm/sub-mm frequencies can adequately describe the spectrum, and suggests that the mechanism driving spectral inversion could be responsible for the high mm/sub-mm fluxes (compared to radio fluxes) observed in outbursting BHXRBs. While this power law is also consistent with contemporaneous optical data, the optical data could arise from either jet emission with a jet spectral break frequency of {{ν }break}≳ 1× {{10}14} Hz or the combination of jet emission with a lower jet spectral break frequency of {{ν }break}≳ 2× {{10}11} Hz and accretion disk emission. Our analysis solidifies the importance of the mm/sub-mm regime in bridging the crucial gap between radio and IR frequencies in the jet spectrum, and justifies the need to explore this regime further.

  18. MRF with adjustable pH

    NASA Astrophysics Data System (ADS)

    Jacobs, Stephen D.

    2011-10-01

    Deterministic final polishing of high precision optics using sub-aperture processing with magnetorheological finishing (MRF) is an accepted practice throughout the world. A wide variety of materials can be successfully worked with aqueous (pH 10), magnetorheological (MR) fluids, using magnetic carbonyl iron (CI) and either ceria or nanodiamond nonmagnetic abrasives. Polycrystalline materials like zinc sulfide (ZnS) and zinc selenide (ZnSe) are difficult to polish at pH 10 with MRF, due to their grain size and the relatively low stiffness of the MR fluid lap. If microns of material are removed, the grain structure of the material begins to appear. In 2005, Kozhinova et al. (Appl. Opt. 44 4671-4677) demonstrated that lowering pH could improve MRF of ZnS. However, magnetic CI particle corrosion rendered their low pH approach unstable and unsuitable for commercial implementation. In 2009, Shafrir et al. described a sol-gel coating process for manufacturing a zirconia-coated CI particle that protects the magnetic core from aqueous corrosion (Appl. Opt .48 6797-6810). The coating process produces free nanozirconia polishing abrasives during the coating procedure, thereby creating an MR polishing powder that is "self-charged" with the polishing abrasive. By simply adding water, it was possible to polish optical glasses and ceramics with good stability at pH 8 for three weeks. The development of a corrosion resistant, MR polishing powder, opens up the possibility for polishing additional materials, wherein the pH may be adjusted to optimize effectiveness. In this paper we describe the CI coating process, the characterization of the coated powder, and procedures for making stable MR fluids with adjustable pH, giving polishing results for a variety of optical glasses and crystalline ceramics.

  19. Eukaryotic diversity at pH extremes

    PubMed Central

    Amaral-Zettler, Linda A.

    2013-01-01

    Extremely acidic (pH < 3) and extremely alkaline (pH > 9) environments support a diversity of single-cell and to a lesser extent, multicellular eukaryotic life. This study compared alpha and beta diversity in eukaryotic communities from seven diverse aquatic environments with pH values ranging from 2 to 11 using massively-parallel pyrotag sequencing targeting the V9 hypervariable region of the 18S ribosomal RNA (rRNA) gene. A total of 946 operational taxonomic units (OTUs) were recovered at a 6% cut-off level (94% similarity) across the sampled environments. Hierarchical clustering of the samples segregated the communities into acidic and alkaline groups. Similarity percentage (SIMPER) analysis followed by indicator OTU analysis (IOA) and non-metric multidimensional scaling (NMDS) were used to determine which characteristic groups of eukaryotic taxa typify acidic or alkaline extremes and the extent to which pH explains eukaryotic community structure in these environments. Spain's Rio Tinto yielded the fewest observed OTUs while Nebraska Sandhills alkaline lakes yielded the most. Distinct OTUs, including metazoan OTUs, numerically dominated pH extreme sites. Indicator OTUs included the diatom Pinnularia and unidentified opisthokonts (Fungi and Filasterea) in the extremely acidic environments, and the ciliate Frontonia across the extremely alkaline sites. Inferred from NMDS, pH explained only a modest fraction of the variation across the datasets, indicating that other factors influence the underlying community structure in these environments. The findings from this study suggest that the ability for eukaryotes to adapt to pH extremes over a broad range of values may be rare, but further study of taxa that can broadly adapt across diverse acidic and alkaline environments, respectively present good models for understanding adaptation and should be targeted for future investigations. PMID:23335919

  20. The Effects of Alkaline pH on Microleakage of Mineral Trioxide Aggregate and Calcium Enriched Mixture Apical Plugs

    PubMed Central

    Mirhadi, Hossein; Moazzami, Fariborz; Rangani Jahromi, Saeed; Safarzade, Sareh

    2016-01-01

    Statement of the Problem Alkaline pH can affect the physical and chemical properties and sealing ability of apical plug material. Calcium hydroxide is used as an intracanal medication to complete disinfection of root canals. It raises the pH of environment to alkaline value. Purpose The aim of this in vitro study was to evaluate and compare the effect of alkaline pH on the sealing ability of calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA) apical plugs. Materials and Method Seventy single-rooted human maxillary anterior teeth were randomly divided to two experimental groups for Angelus MTA and CEM cement (n=30) and two control groups (n=5). Each group was divided into two subgroups of 15 for neutral and alkaline pH, and 1 negative and 1 positive control groups of 5. The root canals were cleaned and shaped by using ProTaper rotary system (Dentsply Maillefer; Ballaigues, Switzerland) and the terminal 3mm of the roots were resected. Then, MTA and CEM cement were condensed in apical region with 3mm thickness. The samples were exposed to two environments with different pH values of 13 and 7.4. The leakage was assessed by using the fluid filtration technique at 1, 7, 14, 30 days intervals. Data were analyzed by the repeated measures MANOVA. Results There was no statistically significant difference in the rate of microleakage between neutral and alkaline pH of CEM cement and MTA (p> 0.05). The sealing ability of MTA in an alkaline pH of 13 was significantly less than CEM cement in this pH (p< 0.05). Conclusion An environment with alkaline pH had no adverse effect on the sealing ability of MTA and CEM cement used as apical plugs. CEM cement had better sealing ability in alkaline pH. PMID:26966703

  1. Molecular dynamics simulations of ion solvation by flexible-boundary QM/MM: on-the-fly partial charge transfer between QM and MM subsystems.

    PubMed

    Pezeshki, Soroosh; Lin, Hai

    2014-09-15

    The flexible-boundary (FB) quantum mechanical/molecular mechanical (QM/MM) scheme accounts for partial charge transfer between the QM and MM subsystems. Previous calculations have demonstrated excellent performance of FB-QM/MM in geometry optimizations. This article reports an implementation to extend FB-QM/MM to molecular dynamics simulations. To prevent atoms from getting unreasonably close, which can lead to polarization catastrophe, empirical correcting functions are introduced to provide additive penalty energies for the involved atom pairs and to improve the descriptions of the repulsive exchange forces in FB-QM/MM calculations. Test calculations are carried out for chloride, lithium, sodium, and ammonium ions solvated in water. Comparisons with conventional QM/MM calculations suggest that the FB treatment provides reasonably good results for the charge distributions of the atoms in the QM subsystems and for the solvation shell structural properties, albeit smaller QM subsystems have been used in the FB-QM/MM dynamics simulations. PMID:25056247

  2. Brain metabolism is significantly impaired at blood glucose below 6 mM and brain glucose below 1 mM in patients with severe traumatic brain injury

    PubMed Central

    2010-01-01

    Introduction The optimal blood glucose target following severe traumatic brain injury (TBI) must be defined. Cerebral microdialysis was used to investigate the influence of arterial blood and brain glucose on cerebral glucose, lactate, pyruvate, glutamate, and calculated indices of downstream metabolism. Methods In twenty TBI patients, microdialysis catheters inserted in the edematous frontal lobe were dialyzed at 1 μl/min, collecting samples at 60 minute intervals. Occult metabolic alterations were determined by calculating the lactate- pyruvate (L/P), lactate- glucose (L/Glc), and lactate- glutamate (L/Glu) ratios. Results Brain glucose was influenced by arterial blood glucose. Elevated L/P and L/Glc were significantly reduced at brain glucose above 1 mM, reaching lowest values at blood and brain glucose levels between 6-9 mM (P < 0.001). Lowest cerebral glutamate was measured at brain glucose 3-5 mM with a significant increase at brain glucose below 3 mM and above 6 mM. While L/Glu was significantly increased at low brain glucose levels, it was significantly decreased at brain glucose above 5 mM (P < 0.001). Insulin administration increased brain glutamate at low brain glucose, but prevented increase in L/Glu. Conclusions Arterial blood glucose levels appear to be optimal at 6-9 mM. While low brain glucose levels below 1 mM are detrimental, elevated brain glucose are to be targeted despite increased brain glutamate at brain glucose >5 mM. Pathogenity of elevated glutamate appears to be relativized by L/Glu and suggests to exclude insulin- induced brain injury. PMID:20141631

  3. pH. Training Module 5.305.2.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with pH, measurement of pH with a pH meter and maintenance of pH meter electrodes. Included are objectives, instructor guides, student handouts and transparency masters. This module considers the definition of pH, types of electrodes and…

  4. Low pH myoglobin photoproducts.

    PubMed Central

    Sage, J T; Morikis, D; Li, P; Champion, P M

    1992-01-01

    Recently, there has been interest in determining the conditions under which the iron-histidine bond ruptures in myoglobin at low pH, so that the effect of proximal heme ligation can be studied. A 220-cm-1 Raman mode, assigned to iron-histidine stretching, is clearly visible after photolysis of aqueous MbCO samples below pH4 at room temperature (Sage et al. Biochemistry. 30:1237-1247). In contrast, Iben et al. (Biophys. J. 59:908-919) do not observe this mode upon photolysis of a pH3 MbCO sample in a glycerol/water glass at low temperature. In order to account for both the low temperature and the room temperature experiments, Iben et al. suggest a scheme involving an unusual protonation state of the proximal histidine. Here, we discuss some inconsistencies in their explanation of the room temperature results and offer instead a simple modification of an earlier model. In addition, circular dichroism data are presented that indicate partial unfolding of MbCO in aqueous solution below pH4, and raise questions about the claim of Iben et al. that MbCO remains folded in 75% glycerol at pH3. PMID:1581497

  5. Detection of the 267 GHz J = 1-0 rotational transition of PH3 in Saturn with a new Fourier transform spectrometer

    NASA Technical Reports Server (NTRS)

    Weisstein, Eric W.; Serabyn, E.

    1994-01-01

    In recent observations at the Caltech Submillimeter Observatory, the highly pressure-broadened (FWHM = 11.2 GHz) J = 1-0 rotational transition of PH3 (phosphine) was detected on Saturn. By modeling the Saturnian atmosphere with a radiative transfer code, the observed line profile was consistent with a constant PH3 mole fraction of 3.0 plus or minus 1.0 ppm in the upper troposphere. A best-fit to the depth of the line implies a cutoff at high altitudes, with no PH3 present at pressures approximately less than 100 mbar. The observed line depth, combined with the lack of a detectable emission core, implies that a cutoff in the PH3 abundance occurs at a pressure between 13 and 140 mbar. PH3 in Jupiter was not detected, nor any other molecular lines between 195 and 295 GHz (1.54 mm and 1.02 mm, respectively) in either Jupiter or Saturn.

  6. pH Wave-Front Propagation in the Urea-Urease Reaction

    PubMed Central

    Wrobel, Magdalena M.; Bánsági, Tamás; Scott, Stephen K.; Taylor, Annette F.; Bounds, Chris O.; Carranza, Arturo; Pojman, John A.

    2012-01-01

    The urease-catalyzed hydrolysis of urea displays feedback that results in a switch from acid (pH ∼3) to base (pH ∼9) after a controllable period of time (from 10 to >5000 s). Here we show that the spatially distributed reaction can support pH wave fronts propagating with a speed of the order of 0.1−1 mm min−1. The experimental results were reproduced qualitatively in reaction-diffusion simulations including a Michaelis-Menten expression for the urease reaction with a bell-shaped rate-pH dependence. However, this model fails to predict that at lower enzyme concentrations, the unstirred reaction does not always support fronts when the well-stirred reaction still rapidly switches to high pH. PMID:22947878

  7. Enhanced morphological transformation of early passage Syrian hamster embryo cells cultured in medium with a reduced bicarbonate concentration and pH.

    PubMed

    LeBoeuf, R A; Kerchaert, G A

    1987-05-01

    Recent studies from our laboratory have demonstrated that clonal cell proliferation of early passage Syrian hamster embryo (SHE) cells is optimal at a bicarbonate concentration in the culture medium of 8.9 mM (pH 6.65-6.75) under the experimental conditions reported. The purpose of the studies reported here was to examine whether morphological transformation induced by benzo[a]pyrene (BP) was enhanced under optimal culture conditions for SHE cell proliferation. Culture media of pH 6.70, 7.11 and 7.34 under incubator conditions of 10% CO2 in air were obtained by the addition of 0.75 (8.9 mM), 2.25 (26.8 mM) and 3.75 g/l (44.6 mM) of NaHCO3 respectively to a modified formulation of Dulbecco's modified Eagles medium. The frequency of morphological transformation of SHE cells was increased at 8.9 mM bicarbonate (pH 6.70) relative to media containing 26.8 or 44.6 mM bicarbonate (pH 7.11 and 7.34 respectively). Additionally, the isolate of embryo cells and lot of fetal bovine serum used supported transformation induced by BP at 8.9 mM bicarbonate (pH 6.70), but did not with media of higher bicarbonate concentration and pH. The duration of cell culture and the no. of colonies per plate influenced the amount of increase of morphological transformation observed at 8.9 mM bicarbonate relative to media of higher bicarbonate concentration. Initial studies have shown that a fraction of morphologically transformed colonies generated at reduced bicarbonate concentration were tumorigenic in newborn hamsters. These results are discussed in terms of the potential utility of low bicarbonate concentration cultured SHE cells for transformation studies. PMID:3581427

  8. The Cytosolic pH of Individual Saccharomyces cerevisiae Cells Is a Key Factor in Acetic Acid Tolerance

    PubMed Central

    Fernández-Niño, Miguel; Marquina, Maribel; Swinnen, Steve; Rodríguez-Porrata, Boris

    2015-01-01

    It was shown recently that individual cells of an isogenic Saccharomyces cerevisiae population show variability in acetic acid tolerance, and this variability affects the quantitative manifestation of the trait at the population level. In the current study, we investigated whether cell-to-cell variability in acetic acid tolerance could be explained by the observed differences in the cytosolic pHs of individual cells immediately before exposure to the acid. Results obtained with cells of the strain CEN.PK113-7D in synthetic medium containing 96 mM acetic acid (pH 4.5) showed a direct correlation between the initial cytosolic pH and the cytosolic pH drop after exposure to the acid. Moreover, only cells with a low initial cytosolic pH, which experienced a less severe drop in cytosolic pH, were able to proliferate. A similar correlation between initial cytosolic pH and cytosolic pH drop was also observed in the more acid-tolerant strain MUCL 11987-9. Interestingly, a fraction of cells in the MUCL 11987-9 population showed initial cytosolic pH values below the minimal cytosolic pH detected in cells of the strain CEN.PK113-7D; consequently, these cells experienced less severe drops in cytosolic pH. Although this might explain in part the difference between the two strains with regard to the number of cells that resumed proliferation, it was observed that all cells from strain MUCL 11987-9 were able to proliferate, independently of their initial cytosolic pH. Therefore, other factors must also be involved in the greater ability of MUCL 11987-9 cells to endure strong drops in cytosolic pH. PMID:26341199

  9. Fiber-Optic pH Sensor

    NASA Astrophysics Data System (ADS)

    Ganesh, A. Balaji; Radhakrishnan, T. K.

    The new enhancement in the determination of pH using optical fiber system is described here. This work uses the membrane made of cellulose acetate membrane for reagent immobilization and congo red (pKa 3.7) and neutral red (pKa 7.2) as pH indicators. An effective covalent chemical binding procedure is used to immobilize the indicatorsE The response time, reversibility, linear range, reproducibility, and long-term stability of fiber optic sensor with congo red as well as neutral red have been determined. The linear range measured for the sensor based on the congo red and neutral red is 4.2-6.3 and 4.1-9.0, respectively. The response time of sensor membrane is measured by varying the substance pH values between 11.0 and 2.0.

  10. Comparison of the holding power of 3.5-mm cortical versus 4.0-mm cancellous orthopedic screws in the pelvis of immature dogs (cadavers).

    PubMed

    Sardinas, J C; Kraus, K H; Sisson, R D

    1995-02-01

    A 3.5-mm cortical orthopedic screw was compared with a 4.0-mm cancellous screw for maximal load to failure in the pelvis of immature dogs. The pelvis from young cadavers (7 to 13 months old) was divided into hemipelves and used for testing of the 2 screw types. Two sites in each hemipelvis were used, mid-shaft of the ilium and mid-sacrum, including the wing of the ilium. The screws were extracted, and maximal load to failure and mode of failure were recorded. Maximal load to failure per millimeter of engaged thread was calculated. In either pelvic site, the 4.0-mm cancellous screw required a significantly (P < 0.05) higher pullout force per millimeter of engaged screw threads than did the 3.5-mm cortical bone screw. PMID:7717594

  11. The effect of pH on charge inversion and condensation of DNA.

    PubMed

    Guo, Zilong; Wang, Yanwei; Yang, Anthony; Yang, Guangcan

    2016-08-21

    Charge inversion and condensation of DNA in solutions of trivalent and quadrivalent counterions are significantly influenced by the pH value of the solution. We systematically investigated the condensation and charge compensation of DNA by spermidine, hexammine cobalt(iii) (cohex, [Co(NH3)6](3+)) and spermine in solutions of a wide range of pH values from 3 to 9.3 by dynamic light scattering, magnetic tweezers, and atomic force microscopy. In trivalent counterion solution, we found that there is a critical concentration (0.75 mM for cohex and 0.5 mM for spermidine), under which the electrophoresis mobility of DNA initially increases, reaches a maximum, and finally decreases when the pH value is decreased. In contrast, above the critical concentration, the electrophoretic mobility of DNA increases monotonously with decreasing pH value of the solution. The corresponding condensing force has the same dependence on the pH value. However, for the case of quadrivalent counterions, the electrophoretic mobility of DNA is monotonously promoted by lowering the pH value of the solution at any concentration of counterions in which charge inversion of DNA may occur. In atomic force microscopy images and force spectroscopy of magnetic tweezers, we found that maximal charge neutralization and condensation force correspond to the most compact DNA condensation. We propose a mechanism of promoting DNA charge neutralization: small and highly mobile hydrogen ions tend to attach to the DNA-counterion complex to further neutralize its remaining charge, which is related to the surface area of the complex. Therefore, this further neutralization is prominent when the complex is toroidal which corresponds to the case of mild ion concentration while it is less prominent for more compact globules or rod complexes at high counterion concentration. PMID:27427090

  12. Assessing the performance of the MM/PBSA and MM/GBSA methods: I. The accuracy of binding free energy calculations based on molecular dynamics simulations

    PubMed Central

    Hou, Tingjun; Wang, Junmei; Li, Youyong; Wang, Wei

    2011-01-01

    The Molecular Mechanics/Poisson Boltzmann Surface Area (MM/PBSA) and the Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) methods calculate binding free energies for macromolecules by combining molecular mechanics calculations and continuum solvation models. To systematically evaluate the performance of these methods, we report here an extensive study of 59 ligands interacting with six different proteins. First, we explored the effects of the length of the molecular dynamics (MD) simulation, ranging from 400 to 4800 ps, and the solute dielectric constant (1, 2 or 4) to the binding free energies predicted by MM/PBSA. The following three important conclusions could be observed: (1). MD simulation lengths have obvious impact on the predictions, and longer MD simulations are not always necessary to achieve better predictions; (2). The predictions are quite sensitive to solute dielectric constant, and this parameter should be carefully determined according to the characteristics of the protein/ligand binding interface; (3). Conformational entropy showed large fluctuations in MD trajectories and a large number of snapshots are necessary to achieve stable predictions. Next, we evaluated the accuracy of the binding free energies calculated by three Generalized Born (GB) models. We found that the GB model developed by Onufriev and Case was the most successful model in ranking the binding affinities of the studied inhibitors. Finally, we evaluated the performance of MM/GBSA and MM/PBSA in predicting binding free energies. Our results showed that MM/PBSA performed better in calculating absolute, but not necessarily relative, binding free energies than MM/GBSA. Considering its computational efficiency, MM/GBSA can serve as a powerful tool in drug design, where correct ranking of inhibitors is often emphasized. PMID:21117705

  13. The control of intracellular pH in cultured avian chondrocytes.

    PubMed Central

    Dascalu, A; Nevo, Z; Korenstein, R

    1993-01-01

    1. Mechanical loading of cartilaginous tissue generates an increase in the concentration of cations in the extracellular matrix. This includes a decrease of the extracellular pH (pHo), which is known to affect the intracellular pH (pHi), thereby modifying the intracellular metabolism. Thus, the regulation of pHi is essential for the physiological function of cartilage. The fluorescent pH-sensitive dye 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein acetoxymethyl ester (BCECF AM) was employed in order to assess the mechanisms responsible for control of the pHi in an embryonic avian chondrocyte cell suspension. 2. Steady-state pHi in the absence of physiological HCO3- was 7.15 +/- 0.01 pH units as compared to a pHi of 6.94 +/- 0.02 pH units in its presence (P < 0.01). The intrinsic buffering power of chondrocytes (beta i) was 38.9 mM/pH unit and the total buffering capacity (beta T) was 65.8 mM/pH unit. 3. Cells maintained in a Hepes-buffered solution were exposed to an intracellular acid load by the NH4+ prepulse technique (20 mM NH4Cl). The initial rate of pHi recovery was 0.106 pH units/min (n = 18). Amiloride (0.33 mM), an inhibitor of the Na(+)-H+ exchanger, or replacement of external sodium [Na+]o with choline induced a 60% inhibition of the recovery rate, indicating a predominant involvement of this antiporter in the response to intracellular acidification. 4. H(+)-ATPase inhibitors (oligomycin 20 micrograms/ml; N,N;-dicyclohexylcarbodiimide (DCC), 0.5 mM; N-ethylmaleimide (NEM), 0.25 mM) and iodomycin (2 mM), a metabolic cell suppressor, reduced acid extrusion by 25% as measured by the NH4Cl prepulse in Hepes-bathed cells. 5. Chondrocytes transferred from a Hepes-buffered solution to a 5% CO2-25 mM HCO3- medium (HCO3- solution) underwent a pHi decrease of approximately 0.20 pH units, followed by a regulatory alkalinizing response of 0.118 pH units/min. The Na(+)-H+ exchanger was responsible for only 15% of this alkalinization (amiloride, 0.33 mM), in contrast

  14. Comparison of Methods To Reweight from Classical Molecular Simulations to QM/MM Potentials.

    PubMed

    Dybeck, Eric C; König, Gerhard; Brooks, Bernard R; Shirts, Michael R

    2016-04-12

    We examine methods to reweight classical molecular mechanics solvation calculations to more expensive QM/MM energy functions. We first consider the solvation free energy difference between ethane and methanol in a QM/MM Hamiltonian from configurations generated in a cheaper MM potential. The solute molecules in the QM/MM Hamiltonian are treated with B3LYP/6-31G*, and the solvent water molecules are treated classically. The free energy difference in the QM/MM Hamiltonian is estimated using Boltzmann reweighting with both the non-Boltzmann Bennett method (NBB) and the multistate Bennett acceptance ratio (MBAR), and the variance of each method is directly compared for an identical data set. For this system, MBAR-derived methods are found to produce smaller overall uncertainties than NBB-based methods. Additionally, we show that to reduce the variance in the overall free energy difference estimate in this system for a fixed amount of QM/MM calculations, the energy re-evaluations in the Boltzmann reweighting step should be concentrated on the physical MM states with the highest overlap to the QM/MM states, rather than allocated equally over all sampled MM states. We also show that reallocating the QM/MM re-evaluations can be used to diagnose poor overlap between the sampled and target state. The solvation free energies for molecules in the SAMPL4 solvation data set are also calculated in the QM/MM Hamiltonian with NBB and MBAR, and the variances are marginally smaller for MBAR. Overall, NBB and MBAR produce similar variances for systems with poor sampling efficiency, and MBAR provides smaller variances than NBB in systems with high sampling efficiency. Both NBB and MBAR converge to identical solvation free energy estimates in the QM/MM Hamiltonian, and the RMSD to experimental values for molecules in the SAMPL4 solvation data set decreases by approximately 28% when switching from the MM Hamiltonian to the QM/MM Hamiltonian. PMID:26928941

  15. Recovery of macroinvertebrates by screening in the field: a comparison between coarse (1.18 mm) and fine (0.60 mm) mesh sieves

    USGS Publications Warehouse

    Dukerschein, J.T.; Gent, R.; Sauer, J.

    1996-01-01

    We evaluated the potential loss of target benthic macroinvertebrates from coarse-mesh field wash down of samples through a 1.18-mm mesh sieve nested on a 0.60-mm mesh sieve. Visible target organisms (midges, mayflies, and fingernail clams) in the 1.18-mm mesh sieve were removed from the sample and enumerated in the field. The entire contents of both sieves were preserved for subsequent laboratory enumeration under 4X magnification. Percent recoveries from each treatment were based on total intact organisms found in all sieves. Percent recovery for fingernail clams found in the field (31%) was lower than for mayflies (79%) and midges (88%). Laboratory enumeration of organisms retained by the 1.18-mm sieve yielded additional fingernail clams (to total 74% recovered in the field and lab), mayflies (to total 89%), and midges (to total 91%). If the 1.18-mm sieve is used alone in the field, it is adequate to monitor mayflies, midges >1 cm, and adult fingernail clams greater than or equal to 5.0 mm shell length.

  16. Comparison of radii sets, entropy, QM methods, and sampling on MM-PBSA, MM-GBSA, and QM/MM-GBSA ligand binding energies of F. tularensis enoyl-ACP reductase (FabI).

    PubMed

    Su, Pin-Chih; Tsai, Cheng-Chieh; Mehboob, Shahila; Hevener, Kirk E; Johnson, Michael E

    2015-09-30

    To validate a method for predicting the binding affinities of FabI inhibitors, three implicit solvent methods, MM-PBSA, MM-GBSA, and QM/MM-GBSA were carefully compared using 16 benzimidazole inhibitors in complex with Francisella tularensis FabI. The data suggests that the prediction results are sensitive to radii sets, GB methods, QM Hamiltonians, sampling protocols, and simulation length, if only one simulation trajectory is used for each ligand. In this case, QM/MM-GBSA using 6 ns MD simulation trajectories together with GB(neck2) , PM3, and the mbondi2 radii set, generate the closest agreement with experimental values (r(2)  = 0.88). However, if the three implicit solvent methods are averaged from six 1 ns MD simulations for each ligand (called "multiple independent sampling"), the prediction results are relatively insensitive to all the tested parameters. Moreover, MM/GBSA together with GB(HCT) and mbondi, using 600 frames extracted evenly from six 0.25 ns MD simulations, can also provide accurate prediction to experimental values (r(2)  = 0.84). Therefore, the multiple independent sampling method can be more efficient than a single, long simulation method. Since future scaffold expansions may significantly change the benzimidazole's physiochemical properties (charges, etc.) and possibly binding modes, which may affect the sensitivities of various parameters, the relatively insensitive "multiple independent sampling method" may avoid the need of an entirely new validation study. Moreover, due to large fluctuating entropy values, (QM/)MM-P(G)BSA were limited to inhibitors' relative affinity prediction, but not the absolute affinity. The developed protocol will support an ongoing benzimidazole lead optimization program. PMID:26216222

  17. pH regulation in anoxic rice coleoptiles at pH 3.5: biochemical pHstats and net H+ influx in the absence and presence of NOFormula.

    PubMed

    Greenway, Hank; Kulichikhin, Konstantin Y; Cawthray, Gregory R; Colmer, Timothy D

    2012-03-01

    During anoxia, cytoplasmic pH regulation is crucial. Mechanisms of pH regulation were studied in the coleoptile of rice exposed to anoxia and pH 3.5, resulting in H(+) influx. Germinating rice seedlings survived a combination of anoxia and exposure to pH 3.5 for at least 4 d, although development was retarded and net K(+) efflux was continuous. Further experiments used excised coleoptile tips (7-10 mm) in anoxia at pH 6.5 or 3.5, either without or with 0.2 mM NO(3)(-), which distinguished two processes involved in pH regulation. Net H(+) influx (μmol g(-1) fresh weight h(-1)) for coleoptiles with NO(3)(-) was ∼1.55 over the first 24 h, being about twice that in the absence of NO(3)(-), but then decreased to 0.5-0.9 as net NO(3)(-) uptake declined from ∼1.3 to 0.5, indicating reduced uptake via H(+)-NO(3)(-) symports. NO(3)(-) reduction presumably functioned as a biochemical pHstat. A second biochemical pHstat consisted of malate and succinate, and their concentrations decreased substantially with time after exposure to pH 3.5. In anoxic coleoptiles, K(+) balancing the organic anions was effluxed to the medium as organic anions declined, and this efflux rate was independent of NO(3)(-) supply. Thus, biochemical pHstats and reduced net H(+) influx across the plasma membrane are important features contributing to pH regulation in anoxia-tolerant rice coleoptiles at pH 3.5. PMID:22174442

  18. Effects of pH, Chloride, and Bicarbonate on Cu(I) Oxidation Kinetics at Circumneutral pH

    NASA Astrophysics Data System (ADS)

    Yuan, X.; Pham, A.; Waite, T.; Xing, G.; Rose, A.

    2012-12-01

    The redox chemistry of copper species in the upper water column plays a significant role in its speciation, transport and bioavailability. Most previous studies have focused primarily on Cu(II), principally because Cu(I) is easily oxidized to Cu(II) by oxygen or other oxidants. However, a growing body of evidence indicates that a number of potentially important reactions may lead to Cu(I) formation and result in a significant steady-state concentration of Cu(I) in natural waters. Redox reactions of Cu(I) could result in the production of reactive oxygen species (ROS), such as superoxide and hydroxyl radical, that may subsequently induce a cascade of radical-promoted reactions with other constituents in natural waters. As such, a better understanding of copper-catalysed processes that produce and consume O2- is important in furthering our insight into factors contributing to global biogeochemical cycles. In this study, the oxidation kinetics of nanomolar concentrations of Cu(I) in NaCl solutions have been investigated over the pH range 6.5-8.0.The overall apparent oxidation rate constant was strongly affected by chloride, moderately by bicarbonate and, and to a lesser extent, by pH. In the absence of bicarbonate, an equilibrium-based speciation model indicated that Cu+ and CuClOH- were the most kinetically reactive species, while the contribution of other Cu(I) species to the overall oxidation rate was minor. A kinetic model based on recognized key redox reactions for these two species further indicated that oxidation of Cu(I) by oxygen and superoxide were important reactions at all pH values and [Cl-] considered, but back reduction of Cu(II) by superoxide only became important at relatively low chloride concentrations. Bicarbonate concentrations from 2-5 mM substantially accelerated Cu(I) oxidation. Kinetic analysis over a range of bicarbonate concentrations revealed that this was due to the formation of CuCO3-, which reacts relatively rapidly with oxygen, and not

  19. In vitro stability of pancreatic zymogen granules: roles of pH and calcium.

    PubMed

    Lebel, D; Grondin, G; Paquette, J

    1988-01-01

    Purified preparations of pancreatic zymogen granules have the peculiar property of lysing instantaneously at neutral pH, a property clearly irreconcilable with the cytoplasmic pH of the acinar cell. Two important factors known for regulating the stability of secretory granules are calcium and pH. Fluorescence microscopy of acinar cells in the presence of weak bases showed that zymogen granules have an acidic pH. In vivo, abolition of the delta pH by NH4Cl did not induce any lysis of the granules. In vitro, with purified granules, an acidic intragranular pH was measured. This delta pH was produced by a Donnan potential. The importance for granule stability of keeping the intragranular pH acidic has been confirmed in vitro by addition of K+ and nigericin to the suspension medium. These conditions produced alkalinization of the granule matrix and caused instantaneous solubilization of the granules. Concentrations of 15 mM total, and 10 mM free calcium were measured in purified granules. The importance of intragranular Ca2+ was evaluated by means of the ionophore A23187 which induced calcium efflux and granule lysis. The lysis induced by the calcium ionophore was in direct relation with the calcium efflux, since addition of Ca2+ to the medium, at concentrations corresponding to that measured in the granule, relieved the effect. The role of calcium-binding sites on the cytoplasmic surface of the granules was investigated with Ca2+, EGTA, and La3+. Calcium did not have any damaging effects; EGTA induced a slight lysis, while lanthanum yielded a strong and spontaneous lysis at micromolar concentrations. In addition to calcium-binding sites, La3+ would bind to specific sites on the granule that would be directly coupled to maintenance of its stability. These findings suggest that the intragranular acidic pH and calcium are both important for the in vitro stability of the zymogen granule and that purified granules have lost, in the course of purification, some cytoplasmic

  20. Periodic Boundary Conditions in QM/MM Calculations: Implementation and Tests.

    PubMed

    Vasilevskaya, Tatiana; Thiel, Walter

    2016-08-01

    Quantum mechanics/molecular mechanics (QM/MM) simulations of reactions in solutions and in solvated enzymes can be performed using the QM/MM-Ewald approach with periodic boundary conditions (PBC) or a nonperiodic treatment with a finite solvent shell (droplet model). To avoid the changes in QM codes that are required in standard QM/MM-Ewald implementations, we present a general method (Gen-Ew) for periodic QM/MM calculations that can be used with any QM method in the QM/MM framework. The Gen-Ew approach approximates the QM/MM-Ewald method by representing the PBC potential by virtual charges on a sphere and the QM density by electrostatic potential (ESP) charges. Test calculations show that the deviations between Gen-Ew and QM/MM-Ewald results are generally small enough to justify the application of the Gen-Ew method in the absence of a suitable QM/MM-Ewald implementation. We compare the results from periodic QM/MM calculations (QM/MM-Ewald, Gen-Ew) to their nonperiodic counterparts (droplet model) for five test reactions in water and for the Claisen rearrangement in chorismate mutase. The periodic and nonperiodic QM/MM treatments give similar free energy profiles for the reactions in solution (umbrella sampling, free energy deviations of the order of 1 kcal/mol) and essentially the same energy profile (constrained geometry optimizations) for the Claisen rearrangement in chorismate mutase. In all cases considered, long-range electrostatic interactions are thus well captured by nonperiodic QM/MM calculations in a water droplet of reasonable size (radius of 15-20 Å). This provides further justification for the widespread use of the computationally efficient droplet model in QM/MM studies of reactions in solution and in enzymes. PMID:27420296

  1. Evaluation of fluorimetric pH sensors for bioprocess monitoring at low pH.

    PubMed

    Janzen, Nils H; Schmidt, Michael; Krause, Christian; Weuster-Botz, Dirk

    2015-09-01

    Optical chemical sensors are the standard for pH monitoring in small-scale bioreactors such as microtiter plates, shaking flasks or other single-use bioreactors. The dynamic pH range of the so far commercially available fluorescent pH sensors applied in small-scale bioreactors is restricted to pH monitoring around neutral pH, although many fermentation processes are performed at pH < 6 on industrial scale. Thus, two new prototype acidic fluorescence pH sensors immobilized in single-use stirred-tank bioreactors, one with excitation at 470 nm and emission at 550 nm (sensor 470/550) and the other with excitation at 505 nm and emission at 600 nm (sensor 505/600), were characterized with respect to dynamic ranges and operational stability in representative fermentation media. Best resolution and dynamic range was observed with pH sensor 505/600 in mineral medium (dynamic range of 3.9 < pH < 7.2). Applying the same pH sensors to complex medium results in a drastic reduction of resolution and dynamic ranges. Yeast extract in complex medium was found to cause background fluorescence at the sensors' operating wavelength combinations. Optical isolation of the sensor by adding a black colored polymer layer above the sensor spot and fixing an aperture made of adhesive photoresistant foil between the fluorescence reader and the transparent bottom of the polystyrene reactors enabled full re-establishment of the sensor's characteristics. Reliability and operational stability of sensor 505/600 was shown by online pH monitoring (4.5 < pH < 5.8) of parallel anaerobic batch fermentations of Clostridium acetobutylicum for the production of acetone, butanol and ethanol (ABE) with offline pH measurements with a standard glass electrode as reference. PMID:25969385

  2. Production of microbial rhamnolipid by Pseudomonas aeruginosa MM1011 for ex situ enhanced oil recovery.

    PubMed

    Amani, Hossein; Müller, Markus Michael; Syldatk, Christoph; Hausmann, Rudolf

    2013-07-01

    Recently, several investigations have been carried out on the in situ bacteria flooding, but the ex situ biosurfactant production and addition to the sand pack as agents for microbial enhanced oil recovery (MEOR) has little been studied. In order to develop suitable technology for ex situ MEOR processes, it is essential to carry out tests about it. Therefore, this work tries to fill the gap. The intention of this study was to investigate whether the rhamnolipid mix could be produced in high enough quantities for enhanced oil recovery in the laboratory scale and prove its potential use as an effective material for field application. In this work, the ability of Pseudomonas aeruginosa MM1011 to grow and produce rhamnolipid on sunflower as sole carbon source under nitrogen limitation was shown. The production of Rha-C10-C10 and Rha2-C10-C10 was confirmed by thin-layer chromatography and high-performance liquid chromatography analysis. The rhamnolipid mixture obtained was able to reduce the surface and interfacial tension of water to 26 and 2 mN/m, respectively. The critical micelle concentration was 120 mg/L. Maximum rhamnolipid production reached to about 0.7 g/L in a shake flask. The yield of rhamnolipid per biomass (Y RL/x ), rhamnolipid per sunflower oil (Y RL/s ), and the biomass per sunflower oil (Y x/s ) for shake flask were obtained about 0.01, 0.0035, and 0.035 g g(-1), respectively. The stability of the rhamnolipid at different salinities, pH and temperature, and also, its emulsifying activity has been investigated. It is an effective surfactant at very low concentrations over a wide range of temperatures, pHs, and salt concentrations, and it also has the ability to emulsify oil, which is essential for enhanced oil recovery. With 120 mg/L rhamnolipid, 27 % of original oil in place was recovered after water flooding from a sand pack. This result not only suggests rhamnolipids as appropriate model biosurfactants for MEOR, but it even shows the potential as a

  3. Ph.D.'s and the Marketplace.

    ERIC Educational Resources Information Center

    Harvey, James

    Throughout the last decade, Ph.D. recipients were accustomed to a job market in which demand for their services far exceeded supply. During the same period, manpower experts predicted this situation would continue in the foreseeable future. However, when the 60's ended, the employment illusion had been rudely dispelled by frantic reports of a…

  4. First-Principles pH Theory

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Hyun; Zhang, S. B.

    2006-03-01

    Despite being one of the most important macroscopic measures and a long history even before the quantum mechanics, the concept of pH has rarely been mentioned in microscopic theories, nor being incorporated computationally into first-principles theory of aqueous solutions. Here, we formulate a theory for the pH dependence of solution formation energy by introducing the proton chemical potential as the microscopic counterpart of pH in atomistic solution models. Within the theory, the general acid-base chemistry can be cast in a simple pictorial representation. We adopt density-functional molecular dynamics to demonstrate the usefulness of the method by studying a number of solution systems including water, small solute molecules such as NH3 and HCOOH, and more complex amino acids with several functional groups. For pure water, we calculated the auto- ionization constant to be 13.2 with a 95 % accuracy. For other solutes, the calculated dissociation constants, i.e., the so- called pKa, are also in reasonable agreement with experiments. Our first-principles pH theory can be readily applied to broad solution chemistry problems such as redox reactions.

  5. The Ph.D. Value Proposition

    ERIC Educational Resources Information Center

    Cooper, Kenneth J.

    2012-01-01

    Atlanta University launched its doctor of arts in humanities (DAH) programs almost 40 years ago, and, since the 1988 merger with Clark College, Clark Atlanta University has continued to award the degrees. This fall, for the first time, its students will be able to earn Ph.D.s in humanities instead. In DAH programs around the country, there's been…

  6. Optoelectronic pH Meter: Further Details

    NASA Technical Reports Server (NTRS)

    Jeevarajan, Antony S.; Anderson, Mejody M.; Macatangay, Ariel V.

    2009-01-01

    A collection of documents provides further detailed information about an optoelectronic instrument that measures the pH of an aqueous cell-culture medium to within 0.1 unit in the range from 6.5 to 7.5. The instrument at an earlier stage of development was reported in Optoelectronic Instrument Monitors pH in a Culture Medium (MSC-23107), NASA Tech Briefs, Vol. 28, No. 9 (September 2004), page 4a. To recapitulate: The instrument includes a quartz cuvette through which the medium flows as it is circulated through a bioreactor. The medium contains some phenol red, which is an organic pH-indicator dye. The cuvette sits between a light source and a photodetector. [The light source in the earlier version comprised red (625 nm) and green (558 nm) light-emitting diodes (LEDs); the light source in the present version comprises a single green- (560 nm)-or-red (623 nm) LED.] The red and green are repeatedly flashed in alternation. The responses of the photodiode to the green and red are processed electronically to obtain the ratio between the amounts of green and red light transmitted through the medium. The optical absorbance of the phenol red in the green light varies as a known function of pH. Hence, the pH of the medium can be calculated from the aforesaid ratio.

  7. Teaching Physics Using PhET Simulations

    ERIC Educational Resources Information Center

    Wieman, C. E.; Adams, W. K.; Loeblein, P.; Perkins, K. K.

    2010-01-01

    PhET Interactive Simulations (sims) are now being widely used in teaching physics and chemistry. Sims can be used in many different educational settings, including lecture, individual or small group inquiry activities, homework, and lab. Here we will highlight a few ways to use them in teaching, based on our research and experiences using them in…

  8. The Economic Contribution of PhDs

    ERIC Educational Resources Information Center

    Casey, Bernard H.

    2009-01-01

    This paper looks at what the value of a doctorate is, both to employers in particular and to society and the economy at large. Given the emphasis many universities and funding agencies/governments are putting upon the development of PhD programmes, this is an issue deserving attention. The paper tries to show how two separate but interrelated…

  9. pH & Rate of Enzymatic Reactions.

    ERIC Educational Resources Information Center

    Clariana, Roy B.

    1991-01-01

    A quantitative and inexpensive way to measure the rate of enzymatic reaction is provided. The effects of different pH levels on the reaction rate of an enzyme from yeast are investigated and the results graphed. Background information, a list of needed materials, directions for preparing solutions, procedure, and results and discussion are…

  10. Mid-term results of 17-mm St. Jude Medical Regent prosthetic valves in elder patients with small aortic annuli: comparison with 19-mm bioprosthetic valves.

    PubMed

    Teshima, Hideki; Ikebuchi, Masahiko; Sano, Toshikazu; Tai, Ryuta; Horio, Naohiro; Irie, Hiroyuki

    2014-09-01

    This study was designed to compare the mid-term outcomes after aortic valve replacement (AVR) between 17-mm mechanical heart valves (MV) and 19-mm bioprosthetic valves (BV) in elderly patients with small aortic annuli. Between 2000 and 2011, 127 consecutive patients (mean age 79 years; 87 % female) underwent AVR for aortic valve stenosis with a small aortic annulus. 19-mm BV (n = 67) was implanted. When the 19-mm BV did not fit the annulus, 17-mm St. Jude Medical Regent prosthetic mechanical valve (n = 60) was used instead of an aortic root-enlargement procedure. The follow-up rate was 94.0 % in the BV group, and 98.5 % in the MV group. No significant differences in survival rate and valve-related complications were found between the 2 groups. In-hospital mortality rates were 1.5 % (n = 1) in the BV group and 5.0 % (n = 3) in the MV group. Late mortality rates were 3.9 % per patient-years (p-y; n = 8) in the BV group, and 6.0 % per p-y (n = 10) in the MV group. Five-year Kaplan-Meier survival rates were 62 % in the BV group, and 72 % in the MV group (log-rank P = 0.280). Freedom from major adverse valve-related stroke and cerebral bleeding events was 92.5 and 98.5 % in the BV group, and 94.7 and 100 % in the MV group. AVR using 17-mm MV in elder patients with small aortic annuli provided equivalent mid-term clinical results to that with 19-mm BV. PMID:24878870

  11. Effect of chloride ion on the sedimentation volume and zeta potential of zinc insulin suspensions in neutral pH range.

    PubMed

    Kim, Y; Cuff, G W; Morris, R M

    1995-06-01

    When zinc insulin suspensions of different pH values were prepared in the presence of sodium chloride, an unusually high sedimentation volume was found at about pH 6.9. An experimental investigation was conducted in an effort to understand this phenomenon. The experiments involved measurements of electrophoretic mobilities to calculate zeta potentials and sedimentation volumes of zinc insulin suspensions prepared at different NaCl concentrations (0, 17, and 120 mM) and at various pH values from 5 to 8. The general trend observed was that the magnitude of the zeta potential increased with pH when it was higher than the isoelectric point of 5.3. When the sodium chloride concentration was 120 mM, a very rapid change in zeta potential was observed in the pH range of 6.6 to 7.2, with a maximum magnitude of zeta potential at about pH 6.9, the same pH that was observed to yield the largest sedimentation volume. Our experimental results indicate that the greatest adsorption of chloride ion on the zinc insulin suspension particles occurred in the same pH range, which appeared to be responsible for the rapid change of zeta potential in that pH range. The experimental data were interpreted by DLVO (Derjaguin, Landau, Vervey, and Overbeek) theory, which involves a comparison of the forces of electrostatic repulsion and of the van der Waals attraction. PMID:7562418

  12. Macroalgae contribute to nested mosaics of pH variability in a sub-Arctic fjord

    NASA Astrophysics Data System (ADS)

    Krause-Jensen, D.; Duarte, C. M.; Hendriks, I. E.; Meire, L.; Blicher, M. E.; Marbà, N.; Sejr, M. K.

    2015-03-01

    The Arctic Ocean is considered the most vulnerable ecosystem to ocean acidification (OA) and large-scale assessments of pH and the saturation state for aragonite (Ωarag) indicate that it is already close to corrosive states (Ωarag < 1). In high-latitude coastal waters the regulation of pH and Ωarag is far more complex than offshore because increased biological activity and input of glacial meltwater affect pH. As most calcifiers occupy coastal habitats, the assessment of risks from OA to these vulnerable organisms cannot be derived from extrapolation of current and forecasted offshore conditions, but requires an understanding of the regimes of pH and Ωarag in their coastal habitats. To increase knowledge of the natural variability of pH in the Arctic coastal zone and specifically to test the influence of benthic vegetated habitats, we quantified pH-variability in a Greenland fjord in a nested scale approach. A sensor array logging pH, O2, PAR, temperature and salinity was applied on spatial scales ranging from km-scale across the horizontal extension of the fjord, over 100 m scale vertically in the fjord, 10-100 m scale between subtidal habitats with and without kelp forests and between vegetated tidal pools and adjacent vegetated shores, to cm-m scale within kelp forests and mm-scale across boundary layers of macrophyte tissue. In addition, we assessed the temporal variability in pH on diurnal and seasonal scales. Based on pH-measurements combined with relationships between salinity, total alkalinity and dissolved inorganic carbon we also estimated variability of Ωarag. Results show variability in pH and Ωarag of up to 0.2-0.3 units at several scales, i.e. along the horizontal and vertical extension of the fjord, between seasons and on a diel basis in benthic habitats and within 1 m3 of kelp forest. Vegetated intertidal pools exhibited extreme diel pH variability of > 1.5 units and macrophyte boundary layers a pH-range of up to 0.8 units. Overall, Ωarag was

  13. Algal and Bacterial Activities in Acidic (pH 3) Strip Mine Lakes

    PubMed Central

    Gyure, Ruth A.; Konopka, Allan; Brooks, Austin; Doemel, William

    1987-01-01

    Reservoir 29 and Lake B are extremely acid lakes (epilimnion pHs of 2.7 and 3.2, respectively), because they receive acidic discharges from coal refuse piles. They differ in that the pH of profundal sediments in Reservoir 29 increased from 2.7 to 3.8 during the period of thermal stratification, whereas permanently anoxic sediments in Lake B had a pH of 6.2. The pH rise in Reservoir 29 sediments was correlated with a temporal increase in H2S concentration in the anaerobic hypolimnion from 0 to >1 mM. The chlorophyll a levels in the epilimnion of Reservoir 29 were low, and the rate of primary production was typical of an oligotrophic system. However, there was a dense 10-cm layer of algal biomass at the bottom of the metalimnion. Production by this layer was low owing to light limitation and possibly H2S toxicity. The specific photosynthetic rates of epilimnetic algae were low, which suggests that nutrient availability is more important than pH in limiting production. The highest photosynthetic rates were obtained in water samples incubated at pH 2.7 to 4. Heterotrophic bacterial activity (measured by [14C]glucose metabolism) was greatest at the sediment/water interface. Bacterial production (assayed by thymidine incorporation) was as high in Reservoir 29 as in a nonacid mesotrophic Indiana lake. PMID:16347430

  14. Influence of Acidic pH on Hydrogen and Acetate Production by an Electrosynthetic Microbiome

    PubMed Central

    LaBelle, Edward V.; Marshall, Christopher W.; Gilbert, Jack A.; May, Harold D.

    2014-01-01

    Production of hydrogen and organic compounds by an electrosynthetic microbiome using electrodes and carbon dioxide as sole electron donor and carbon source, respectively, was examined after exposure to acidic pH (∼5). Hydrogen production by biocathodes poised at −600 mV vs. SHE increased>100-fold and acetate production ceased at acidic pH, but ∼5–15 mM (catholyte volume)/day acetate and>1,000 mM/day hydrogen were attained at pH ∼6.5 following repeated exposure to acidic pH. Cyclic voltammetry revealed a 250 mV decrease in hydrogen overpotential and a maximum current density of 12.2 mA/cm2 at −765 mV (0.065 mA/cm2 sterile control at −800 mV) by the Acetobacterium-dominated community. Supplying −800 mV to the microbiome after repeated exposure to acidic pH resulted in up to 2.6 kg/m3/day hydrogen (≈2.6 gallons gasoline equivalent), 0.7 kg/m3/day formate, and 3.1 kg/m3/day acetate ( = 4.7 kg CO2 captured). PMID:25333313

  15. A miniature fiber optic pH sensor for physiological use.

    PubMed

    Goldstein, S R; Peterson, J I; Fitzgerald, R V

    1980-05-01

    A flexible 0.4-mm-dia pH probe potentially suitable for physiological use has been developed. It is based on the concept of utilizing two single plastic fiber optic strands to illuminate and remotely sense the color change of a dye indicator contained within an acutely implanted sealed cellulosic hollow fiber permeable to hydrogen ions. A supporting electronic module provides tungsten filament illumination, light sensing with a photodiode/operational amplifier, analog and digital circuitry to provide appropriate signal averaging and processing, and a mechanical assembly to enable the optical density measurements to be made both at 560 nm and, for normalization purposes, in the red. Over the physiological pH range from 7.0 to 7.4, the fiber optic probe agrees with a standard glass pH electrode to within 0.01 pH units in buffer solutions, to within 0.017 pH units in heparinized dog blood in vitro, and it has performed successfully while implanted in the jugular vein of a sheep. PMID:7412236

  16. Long period grating-based ocean pH sensor in an SMS fiber

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Klimov, Denis; Kolber, Zbigniew

    2008-03-01

    A long period grating-based pH sensor has been designed in order to measure the pH in the ocean. The pH-sensitive hydrogel, which is made through the thermal crosslink of poly vinyl alcohol and poly acrylic acid, can swell or contract in response to the pH change in the surrounding environment. The sensor is designed in a single mode-multimode-single mode (SMS) fiber structure. The long period grating is written into the multimode fiber of the SMS structure using a focused CO II laser at the critical period (1 mm) of this particular multimode fiber. The hydrogel is glued underneath the SMS structure and will physically stretch or compress the long period grating hence change the phase matching condition in the SMS structure. Because of the different core sizes of the single mode fiber and the multimode fiber, only energy coupled in and out of the fundamental mode in the multimode fiber will be detected directly. The SMS structure has a higher sensitivity than using just the multimode sensing fiber. This sensor has been utilized in the seawater pH sensing in the range of 6 ~ 8. Experiments show that the sensor has a pH resolution of 0.0042.

  17. Anion Conductance of Frog Muscle Membranes: One Channel, Two Kinds of pH Dependence

    PubMed Central

    Woodbury, J. W.; Miles, P. R.

    1973-01-01

    Anion conductance and permeability sequences were obtained for frog skeletal muscle membranes from the changes in characteristic resistance and transmembrane potential after the replacement of one anion by another in the bathing solution. Permeability and conductance sequences are the same. The conductance sequence at pH = 7.4 is Cl- Br- > NO3- > I- > trichloroacetate ≥ benzoate > valerate > butyrate > proprionate > formate > acetate ≥ lactate > benzenesulfonate ≥ isethionate > methylsulfonate > glutamate ≥ cysteate. The anions are divided into two classes: (a) Chloride-like anions (Cl- through trichloroacetate) have membrane conductances that decrease as pH decreases. The last six members of the complete sequence are also chloride like. (b) Benzoate-like anions (benzoate through acetate) have conductances that increase as pH decreases. At pH = 6.7 zinc ions block Cl- and benzoate conductances with inhibitory dissociation constants of 0.12 and 0.16 mM, respectively. Chloride-like and benzoate-like anions probably use the same channels. The minimum size of the channel aperture is estimated as 5.5 x 6.5 Å from the dimensions of the largest permeating anions. A simple model of the channel qualitatively explains chloride-like and benzoate-like conductance sequences and their dependence on pH. PMID:4542368

  18. Influence of acidic pH on hydrogen and acetate production by an electrosynthetic microbiome

    SciTech Connect

    LaBelle, Edward V.; Marshall, Christopher W.; Gilbert, Jack A.; May, Harold D.; Battista, John R.

    2014-10-15

    Production of hydrogen and organic compounds by an electrosynthetic microbiome using electrodes and carbon dioxide as sole electron donor and carbon source, respectively, was examined after exposure to acidic pH (~5). Hydrogen production by biocathodes poised at -600 mV vs. SHE increased>100-fold and acetate production ceased at acidic pH, but ~5–15 mM (catholyte volume)/day acetate and>1,000 mM/day hydrogen were attained at pH ~6.5 following repeated exposure to acidic pH. Cyclic voltammetry revealed a 250 mV decrease in hydrogen overpotential and a maximum current density of 12.2 mA/cm2 at -765 mV (0.065 mA/cm2 sterile control at -800 mV) by the Acetobacterium-dominated community. Supplying -800 mV to the microbiome after repeated exposure to acidic pH resulted in up to 2.6 kg/m3/day hydrogen (≈2.6 gallons gasoline equivalent), 0.7 kg/m3/day formate, and 3.1 kg/m3/day acetate ( = 4.7 kg CO2 captured).

  19. Influence of acidic pH on hydrogen and acetate production by an electrosynthetic microbiome

    DOE PAGESBeta

    LaBelle, Edward V.; Marshall, Christopher W.; Gilbert, Jack A.; May, Harold D.; Battista, John R.

    2014-10-15

    Production of hydrogen and organic compounds by an electrosynthetic microbiome using electrodes and carbon dioxide as sole electron donor and carbon source, respectively, was examined after exposure to acidic pH (~5). Hydrogen production by biocathodes poised at -600 mV vs. SHE increased>100-fold and acetate production ceased at acidic pH, but ~5–15 mM (catholyte volume)/day acetate and>1,000 mM/day hydrogen were attained at pH ~6.5 following repeated exposure to acidic pH. Cyclic voltammetry revealed a 250 mV decrease in hydrogen overpotential and a maximum current density of 12.2 mA/cm2 at -765 mV (0.065 mA/cm2 sterile control at -800 mV) by the Acetobacterium-dominatedmore » community. Supplying -800 mV to the microbiome after repeated exposure to acidic pH resulted in up to 2.6 kg/m3/day hydrogen (≈2.6 gallons gasoline equivalent), 0.7 kg/m3/day formate, and 3.1 kg/m3/day acetate ( = 4.7 kg CO2 captured).« less

  20. Effect of electrolyte pH on CIEF with narrow pH range ampholytes.

    PubMed

    Páger, Csilla; Vargová, Andrea; Takácsi-Nagy, Anna; Dörnyei, Ágnes; Kilár, Ferenc

    2012-11-01

    CIEF of components following sequential injection of ampholytes and the sample zone offers unique advantages for analysis. The most important one of these is the efficient separation of amphoteric compounds having pIs outside the pH range of the ampholytes applied, but the resolution of the components can be increased by an adequate setup in the injection protocol. In this study, the effect of the pH of the anolyte and catholyte on the selectivity and speed of the isoelectric focusing was investigated. Changes in the pH values significantly influenced the resolution and the length of the pH gradient, while changes in the charge state of components were also observed. Three ampholyte solutions (from different suppliers) covering only two pH units were used for the analyses of substituted nitrophenol dyes in uncoated capillary. With appropriate setup, the components, with pIs not covered by the ampholyte pH range, migrated in charged state outside the pH gradient. This phenomenon is preferable for coupling isoelectric focusing to MS detection, by evading the undesirable ion suppression effect of ampholytes. PMID:23086725

  1. A positron tomograph with 600 BGO crystals and 2. 6 mm resolution

    SciTech Connect

    Derenzo, S.E.; Huesman, R.H.; Cahoon, J.L.; Geyer, A.B.; Moses, W.W.; Uber, D.C.; Vuletich, T.; Budinger, T.F.

    1988-02-01

    The authors describe the imaging performance of the Donner 600-Crystal Positron Tomograph, a single 60 cm diam ring of 3 mm wide bismuth germanate (BGO) crystals coupled individually to 14 mm phototubes. With a pulse height threshold of 200 keV and a slice thickness of 5 mm, the sensitivity is 7024 events/sec per ..mu..Ci/ml in a 20 cm cylinder of water. The measured rates for 18 ..mu..Ci/ml are 95,000 trues/sec plus 20,000 random/sec. A 0.3 mm diam /sup 22/Na line source near the center of the tomograph has a circular point spread function (PSF) with a full-width at half-maximum (fwhm) of 2.6 mm. At 5 cm from the center the PSF is elliptical with a fwhm of 2.7 mm tangential x 3.2 mm radial. At 10 cm the PSF has a fwhm of 2.8 mm tangential x 4.8 mm radial. Attenuation data are accumulated with a 20 mCi /sup 68/Ge orbiting transmission source and 100 million coincident events are collected in 200 sec.

  2. A positron tomograph with 600 BGO (bismuth germanate) crystals and 2. 6 mm resolution

    SciTech Connect

    Derenzo, S.E.; Huesman, R.H.; Cahoon, J.L.; Geyer, A.B.; Moses, W.W.; Uber, D.C.; Vuletich, T.; Budinger, T.F.

    1987-10-01

    We describe the imaging performance of the Donner 600-Crystal Positron Tomograph, a single 600 cm diam ring of 3 mm wide bismuth germanate (BGO) crystals coupled individually to 14 mm phototubes. With a pulse height threshold of 200 keV and a slice thickness of 5 mm, the sensitivity is 7024 eventssec per ..mu..Ciml in a 20 cm cyliner of water. The measured rates for 18 ..mu..Ciml are 95,000 truessec plus 20,000 randomsec. A 0.3 mm diam /sup 22/Na line source near the center of the tomograph has a circular point spread function (PSF) with a full-width at half-maximum (fwhm) of 2.6 mm. At 5 cm from the center the PSF is elliptical with a fwhm of 2.7 mm tangential )times) 3.2 mm radial. At 10 cm the PSF has a fwhm of 2.8 mm tangential )times) 4.8 mm radial. Attenuation data are accumulated with a 20 mCi /sup 68/Ge orbiting transmission source and 100 million coincident events are collected in 200 sec. 20 refs., 9 figs., 5 tabs

  3. Conventional metrizamide myelography (MM) and computed tomographic metrizamide myelography (CTMM) in scoliosis: a comparative study

    SciTech Connect

    Pettersson, H.; Harwood-Nash, D.C.; Fitz, C.R.; Chuang, H.S.; Armstrong, E.

    1982-01-01

    A retrospective examination was performed to assess the accuracy of metrizamide myelography (MM) and computed tomographic metrizamide myelography (CTMM) in scoliosis. Of 81 consecutive scoliotic children studied by myelography, 30 had only MM while the remaining 51 had CTMM immediately afterward. CTMM added esential diagnostic information in 13 cases of dysraphism and 4 cases, both methods gave the same imformation. The outhors conclude that in patients with severe scoliosis, dysraphism, and scoliosis with localized neurological disturbances, CTMM should always be added to MM or be the only examination; while in idiopathic scoliosis with vague neurological disturbances a survey of the entire spine is essential, preferably with MM.

  4. ADIFOR working note No. 11: ADIFOR strategies related to POINTER usage in MM5

    SciTech Connect

    Bischof, C.; Khademi, P.; Knauff, T.

    1994-03-01

    POINTERs are nonstandard Fortran statements which cannot be processed by ADIFOR. We are interested in generating derivative code for MM5, a mesoscale model code which uses POINTERs extensively and in a particular structured manner. We briefly report on POINTERs and their role in MM5 and, for their particular usage in MM5, describe the three-step code transformation scheme consisting of pre-ADIFOR, ADIFOR, and post-ADIFOR transformations that result in the generation of correct derivative code for MM5.

  5. A practical large scale/high speed data distribution system using 8 mm libraries

    NASA Technical Reports Server (NTRS)

    Howard, Kevin

    1993-01-01

    Eight mm tape libraries are known primarily for their small size, large storage capacity, and low cost. However, many applications require an additional attribute which, heretofore, has been lacking -- high transfer rate. Transfer rate is particularly important in a large scale data distribution environment -- an environment in which 8 mm tape should play a very important role. Data distribution is a natural application for 8 mm for several reasons: most large laboratories have access to 8 mm tape drives, 8 mm tapes are upwardly compatible, 8 mm media are very inexpensive, 8 mm media are light weight (important for shipping purposes), and 8 mm media densely pack data (5 gigabytes now and 15 gigabytes on the horizon). If the transfer rate issue were resolved, 8 mm could offer a good solution to the data distribution problem. To that end Exabyte has analyzed four ways to increase its transfer rate: native drive transfer rate increases, data compression at the drive level, tape striping, and homogeneous drive utilization. Exabyte is actively pursuing native drive transfer rate increases and drive level data compression. However, for non-transmitted bulk data applications (which include data distribution) the other two methods (tape striping and homogeneous drive utilization) hold promise.

  6. Electronic Absorption Spectra from MM and ab initio QM/MM Molecular Dynamics: Environmental Effects on the Absorption Spectrum of Photoactive Yellow Protein

    PubMed Central

    Isborn, Christine M.; Götz, Andreas W.; Clark, Matthew A.; Walker, Ross C.; Martínez, Todd J.

    2012-01-01

    We describe a new interface of the GPU parallelized TeraChem electronic structure package and the Amber molecular dynamics package for quantum mechanical (QM) and mixed QM and molecular mechanical (MM) molecular dynamics simulations. This QM/MM interface is used for computation of the absorption spectra of the photoactive yellow protein (PYP) chromophore in vacuum, aqueous solution, and protein environments. The computed excitation energies of PYP require a very large QM region (hundreds of atoms) covalently bonded to the chromophore in order to achieve agreement with calculations that treat the entire protein quantum mechanically. We also show that 40 or more surrounding water molecules must be included in the QM region in order to obtain converged excitation energies of the solvated PYP chromophore. These results indicate that large QM regions (with hundreds of atoms) are a necessity in QM/MM calculations. PMID:23476156

  7. Relation between pH in the Trunk and Face: Truncal pH Can Be Easily Predicted from Facial pH

    PubMed Central

    Kim, Sung Ae; Kim, Bo Ri; Chun, Mi Young

    2016-01-01

    Background The clinical symptoms of facial and truncal acne differ. Skin surface acidity (pH), which is affected by sebum secretions, reflects the different clinical characteristics of the face and trunk. However, no studies have been conducted on truncal sebum production and skin pH. Objective We evaluated the differences and relationship between pH values of the face and trunk. We also evaluated the relationship between pH and the quantity of sebum produced in the trunk. Methods A total of 35 female patients clinically diagnosed with truncal acne were included. We measured pH on the face and truncal area using the Skin-pH-Meter PH 905®. We measured truncal sebum secretions using the Sebumeter SM 815®. Statistical analysis was performed to evaluate the correlations and differences between pH and sebum. Results Facial pH was significantly higher than chest and back pH values. The correlation between pH on the trunk and the face was significant. We used linear regression equations to estimate truncal pH using only measured pH from the chin. There was no significant relationship between truncal sebum secretion and pH. Conclusion This was the first study that evaluated the differences and correlations between facial and truncal pH. We found that facial pH can predict truncal pH. In addition, we conclude that differences in pH and sebum secretion between the face and trunk are one of the reasons for differences in acne symptom at those sites. PMID:27081270

  8. The pH of Enceladus' ocean

    NASA Astrophysics Data System (ADS)

    Glein, Christopher R.; Baross, John A.; Waite, J. Hunter

    2015-08-01

    Saturn's moon, Enceladus, is a geologically active waterworld. The prevailing paradigm is that there is a subsurface ocean that erupts to the surface, which leads to the formation of a plume of vapor and ice above the south polar region. The chemistry of the ocean is just beginning to be understood, but is of profound geochemical and astrobiological interest. Here, we determine the pH of the ocean using a thermodynamic model of carbonate speciation. Observational data from the Cassini spacecraft are used to make a chemical model of ocean water on Enceladus. The model suggests that Enceladus' ocean is a Na-Cl-CO3 solution with an alkaline pH of ∼11-12. The dominance of aqueous NaCl is a feature that Enceladus' ocean shares with terrestrial seawater, but the ubiquity of dissolved Na2CO3 suggests that soda lakes are more analogous to the Enceladus ocean. The high pH implies that the hydroxide ion should be relatively abundant, while divalent metals should be present at low concentrations owing to buffering by carbonates and phyllosilicates on the ocean floor. Carboxyl groups in dissolved organic species would be negatively charged, while amino groups would exist predominately in the neutral form. Knowledge of the pH improves our understanding of geochemical processes in Enceladus' ocean. The high pH is interpreted to be a key consequence of serpentinization of chondritic rock, as predicted by prior geochemical reaction path models; although degassing of CO2 from the ocean may also play a role depending on the efficiency of mixing processes in the ocean. Serpentinization leads to the generation of H2, a geochemical fuel that can support both abiotic and biological synthesis of organic molecules such as those that have been detected in Enceladus' plume. Serpentinization and H2 generation should have occurred on Enceladus, like on the parent bodies of aqueously altered meteorites; but it is unknown whether these critical processes are still taking place, or if

  9. Regulation of intracellular pH in cnidarians: response to acidosis in Anemonia viridis.

    PubMed

    Laurent, Julien; Venn, Alexander; Tambutté, Éric; Ganot, Philippe; Allemand, Denis; Tambutté, Sylvie

    2014-02-01

    The regulation of intracellular pH (pHi) is a fundamental aspect of cell physiology that has received little attention in studies of the phylum Cnidaria, which includes ecologically important sea anemones and reef-building corals. Like all organisms, cnidarians must maintain pH homeostasis to counterbalance reductions in pHi, which can arise because of changes in either intrinsic or extrinsic parameters. Corals and sea anemones face natural daily changes in internal fluids, where the extracellular pH can range from 8.9 during the day to 7.4 at night. Furthermore, cnidarians are likely to experience future CO₂-driven declines in seawater pH, a process known as ocean acidification. Here, we carried out the first mechanistic investigation to determine how cnidarian pHi regulation responds to decreases in extracellular and intracellular pH. Using the anemone Anemonia viridis, we employed confocal live cell imaging and a pH-sensitive dye to track the dynamics of pHi after intracellular acidosis induced by acute exposure to decreases in seawater pH and NH₄Cl prepulses. The investigation was conducted on cells that contained intracellular symbiotic algae (Symbiodinium sp.) and on symbiont-free endoderm cells. Experiments using inhibitors and Na⁺-free seawater indicate a potential role of Na⁺/H⁺ plasma membrane exchangers (NHEs) in mediating pHi recovery following intracellular acidosis in both cell types. We also measured the buffering capacity of cells, and obtained values between 20.8 and 43.8 mM per pH unit, which are comparable to those in other invertebrates. Our findings provide the first steps towards a better understanding of acid-base regulation in these basal metazoans, for which information on cell physiology is extremely limited. PMID:24256552

  10. Shear bond strength of one-step self-etch adhesives: pH influence

    PubMed Central

    Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

    2015-01-01

    Background: The aim of this study was to compare the shear bond strength of four one-step self-etch adhesives with different pH values to enamel and dentin. Materials and Methods: In this in vitro study, 200 bovine permanent mandibular incisors were used. Four one-step self-etch adhesives with different pH values were tested both on enamel and on dentin: Adper™ Easy Bond Self-Etch Adhesive (pH = 0.8-1), Futurabond NR (pH=2), G-aenial Bond (pH = 1.5), Clearfil S3 Bond (pH = 2.7). After adhesive systems application, a nanohybrid composite resin was inserted into the bonded surface. The specimens were placed in a universal testing machine. The shear bond strength was performed at a cross-head speed of 1 mm/min until the sample rupture. The shear bond strength values (MPa) of the different groups were compared with analysis of variance after that Kolmogorov and Smirnov tests were applied to assess normality of distributions. P < 0.05 was considered as significant. Results: In enamel shear bond strength, the highest shear bond strength values were reported with Futurabond NR (P < 0.01); however, no significant differences were found with Clearfil S3 Bond. The others adhesive systems showed lower shear bond strength values with significant differences between them (P < 0.05). When comparing the dentin shear bond strength, the lowest shear bond strength values were reported with Clearfil S3 Bond (P < 0.05), while there were no significant differences among the other three products (P > 0.05). Conclusion: The pH values of adhesive systems did not influence significantly their shear bond strength to enamel or dentin. PMID:26005459

  11. What Is a pH Probe Study?

    MedlinePlus

    What is a pH Probe Study ? What is pH a probe study? M easuring the pH in the esophagus helps determine whether or not acid is coming up from the stomach. A pH probe study is usually done in patients where ...

  12. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  13. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  14. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  15. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  16. 21 CFR 876.1400 - Stomach pH electrode.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  17. Sensing pH with TMCs.

    PubMed

    Spalthoff, Christian; Göpfert, Martin C

    2016-07-01

    Transmembrane channel-like (TMC) proteins have been implicated in hair cell mechanotransduction, Drosophila proprioception, and sodium sensing in the nematode C. elegans. In this issue of Neuron, Wang et al. (2016) report that C. elegans TMC-1 mediates nociceptor responses to high pH, not sodium, allowing the nematode to avoid strongly alkaline environments in which most animals cannot survive. PMID:27387645

  18. Complexation Key to a pH Locked Redox Reaction

    ERIC Educational Resources Information Center

    Rizvi, Masood Ahmad; Dangat, Yuvraj; Shams, Tahir; Khan, Khaliquz Zaman

    2016-01-01

    An unfavorable pH can block a feasible electron transfer for a pH dependent redox reaction. In this experiment, a series of potentiometric titrations demonstrate the sequential loss in feasibility of iron(II) dichromate redox reaction over a pH range of 0-4. The pH at which this reaction failed to occur was termed as a pH locked reaction. The…

  19. Toward QM/MM Simulation of Enzymatic Reactions with the Drude Oscillator Polarizable Force Field.

    PubMed

    Boulanger, Eliot; Thiel, Walter

    2014-04-01

    The polarization of the environment can influence the results from hybrid quantum mechanical/molecular mechanical (QM/MM) simulations of enzymatic reactions. In this article, we address several technical aspects in the development of polarizable QM/MM embedding using the Drude Oscillator (DO) force field. We propose a stable and converging update of the DO polarization state for geometry optimizations and a suitable treatment of the QM/MM-DO boundary when the QM and MM regions are separated by cutting through a covalent bond. We assess the performance of our approach by computing binding energies and geometries of three selected complexes relevant to biomolecular modeling, namely the water trimer, the N-methylacetamide dimer, and the cationic bis(benzene)sodium sandwich complex. Using a recently published MM-DO force field for proteins, we evaluate the effect of MM polarization on the QM/MM energy profiles of the enzymatic reactions catalyzed by chorismate mutase and by p-hydroxybenzoate hydroxylase. We find that inclusion of MM polarization affects the computed barriers by about 10%. PMID:26580386

  20. The Development and Demise of 8 MM Film Loops in America.

    ERIC Educational Resources Information Center

    Butler, Rebecca P.

    Educators in the late 1960s and early 1970s found that 8 mm film loop cartridges encouraged learning techniques such as self-tutorials, individualized instruction, and small-group participation. The single concept approach used in the production of most 8 mm cartridges contributed to alternative learning strategies in these settings. The…

  1. Young’s modulus calculations for cellulose Iß by MM3 and quantum mechanics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantum mechanics (QM) and molecular mechanics (MM) calculations were performed to elucidate Young’s moduli for a series of cellulose Iß models. Computations using the second generation empirical force field MM3 with a disaccharide cellulose model, 1,4'-O-dimethyl-ß-cellobioside (DMCB), and an analo...

  2. Estimation of the Young’s modulus of cellulose Iß by MM3 and quantum mechanics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Young’s modulus provides a measure of the resistance to deformation of an elastic material. In this study, modulus estimations for models of cellulose Iß relied on calculations performed with molecular mechanics (MM) and quantum mechanics (QM) programs. MM computations used the second generation emp...

  3. A Directory of 3,300 16mm Film Libraries. Bulletin, 1956, No. 12

    ERIC Educational Resources Information Center

    Office of Education, US Department of Health, Education, and Welfare, 1956

    1956-01-01

    This directory of 16mm film libraries has been compiled for the use of teachers, school administrators, librarians, community leaders, and others who use or wish to use motion pictures in their programs. It is a revision and an expansion of the Office of Education publication, "A Directory of 2,660 16mm Film Libraries," which was prepared and…

  4. A Directory of 2660 16mm Film Libraries. Bulletin, 1953, No. 7

    ERIC Educational Resources Information Center

    Reid, Seerley; Carpenter, Anita

    1953-01-01

    This directory of 16mm film libraries has been compiled for the use of teachers, school administrators, librarians, community leaders, and others who use or wish to use motion pictures in their educational and informational programs. It is a revision and an expansion of the Office of Education publication, "A Directory of 2,002 16mm Film…

  5. Condensation heat transfer characteristics of R410A-oil mixture in 5 mm and 4 mm outside diameter horizontal microfin tubes

    SciTech Connect

    Huang, Xiangchao; Ding, Guoliang; Hu, Haitao; Zhu, Yu.; Gao, Yifeng; Deng, Bin

    2010-10-15

    Condensation heat transfer characteristics of R410A-oil mixture in 5 mm and 4 mm outside diameter horizontal microfin tubes were investigated experimentally. The experimental condensing temperature is 40 C, and nominal oil concentration range is from 0% to 5%. The test results indicate that the presence of oil deteriorates the heat transfer. The deterioration effect is negligible at nominal oil concentration of 1%, and becomes obvious with the increase of nominal oil concentration. At 5% nominal oil concentration, the heat transfer coefficient of R410A-oil mixture is found to have a maximum reduction of 25.1% and 23.8% for 5 mm and 4 mm tubes, respectively. The predictabilities of the existing condensation heat transfer correlations were verified with the experimental data, and Yu and Koyama correlation shows the best predictability. By replacing the pure refrigerant properties with the mixture's properties, Yu and Koyama correlation has a deviation of -15% to + 20% in predicting the local condensation heat transfer coefficient of R410A-oil mixture. (author)

  6. Reactivity of the isolable disilene R*PhSi=SiPhR* (R* = SitBu3).

    PubMed

    Wiberg, Nils; Niedermayer, Wolfgang; Polborn, Kurt; Mayer, Peter

    2002-06-17

    The disilene R*PhSi=SiPhR* (R* = supersilyl = SitBu3), which can be quantitatively prepared by dehalogenation of the disilane R*PhClSi-SiBrPhR* with NaR* (yellow, water- and air-sensitive crystals; decomp at ca. 70 degrees C; Si=Si distance 2.182 A), is comparatively reactive. It transforms 1) with Cl2, Br2, HCl, HBr, and HOH under 1,2-addition into disilanes R*PhXSi-SiX'PhR* (X/X' = Hal/Hal, H/Hal, H/OH), 2) with O2, S8, and Sen under insertion into 1,3-disiletanes R*PhSi(-Y-)2SiPhR* (Y = O, S, Se), 3) with Me2C=CH2 under ene reaction into the disilane R*PhRSi-SiHPhR* (R = CH2-CMe=CH2), 4) with N2O, Ten, tBuN identical to C, and Me3SiN=N=N under [2 + 1] cycloaddition into disiliranes -R*PhSi-Y-SiPhR*- (Y = O, Te, C=NtBu, NSiMe3; P4 adds 2 molecules of disilene), 5) with CO2, COS, PhCHO, and Ph2CS under [2 + 2] cycloaddition into disiletanes -R*PhSi-SiPhR*-Y-CO- (Y = O, S) as well as -R*PhSi-SiPhR*-Y-CRPh- (Y/R = O/H, S/Ph), 6) with CS2 and CSe2 under [2 + 3] cycloaddition into ethenes R*2Ph2Si2Y2C = CY2Si2Ph2R*2 (Y = S, Se), and 7) with CH2 = CMe-CMe=CH2 and Ph2CO under [2 + 4] cycloaddition into "Diels-Alder adducts". X-ray structure analyses of seven of these compounds are presented. PMID:12391651

  7. Evaluation of the /sup 11/CO/sub 2/ positron emission tomographic method for measuring brain pH. I. pH changes measured in states of altered PCO/sub 2/

    SciTech Connect

    Buxton, R.B.; Alpert, N.M.; Babikian, V.; Weise, S.; Correia, J.A.; Ackerman, R.H.

    1987-12-01

    The /sup 11/CO/sub 2/ method for measuring local brain pH with positron emission tomography (PET) has been experimentally evaluated, testing the adequacy of the kinetic model and the ability of the method to measure changes in brain pH. Plasma and tissue time/activity curves measured during and following continuous inhalation of /sup 11/CO/sub 2/ were fit with a kinetic model that includes effects of tissue pH, blood flow, and fixation of CO/sub 2/ into compounds other than dissolved gas and bicarbonate ions. For each of ten dogs, brain pH was measured with PET at two values of PaCO/sub 2/ (range 21-67 mm Hg). The kinetic model fit the data well during both inhalation and washout of the label, with residual root mean square (RMS) deviations of the model from the measurements consistent with the statistical quality of the PET data. Brain pH calculated from the PET data shows a linear variation with log(PaCO/sub 2/). These results were in good agreement with previously reported measurements of brain pH, both in absolute value and in variation with PCO/sub 2/. The interpretation of these pH values in normal and pathological states is discussed.

  8. The Added Value of a PhD in Medicine--PhD Students' Perceptions of Acquired Competences

    ERIC Educational Resources Information Center

    Anttila, Henrika; Lindblom-Ylänne, Sari; Lonka, Kristi; Pyhältö, Kirsi

    2015-01-01

    PhD in the field of medicine is more common than in any other domain. Many medical doctors are driven towards PhD, but also students with other backgrounds (usually MSc) are conducting a PhD in medical schools. Higher education has invested a lot in developing generic and research competences. Still little is known about how PhD students…

  9. Design of the multilayer insulation system for the Superconducting Super Collider 50mm dipole cryostat

    SciTech Connect

    Boroski, W.N.; Nicol, T.H.; Schoo, C.J.

    1991-03-01

    The development of the multilayer insulation (MLI) system for the Superconducting Super Collider (SSC) 50 mm collider dipole cryostat is an ongoing extension of work conducted during the 40 mm cryostat program. While the basic design of the MLI system for the 50 mm cryostat resembles that of the 40 mm cryostat, results from measurements of MLI thermal performance below 80K have prompted a re-design of the MLI system for the 20K thermal radiation shield. Presented is the design of the MLI system for the 50 mm collider dipole cryostat, with discussion focusing on system performance, blanket geometry, cost-effective fabrication techniques, and built-in quality control measures that assure consistent thermal performance throughout the SSC accelerator. 16 refs., 8 figs., 2 tabs.

  10. Is There a Benefit to Head Size Greater Than 36 mm in Total Hip Arthroplasty?

    PubMed

    Haughom, Bryan D; Plummer, Darren R; Moric, Mario; Della Valle, Craig J

    2016-01-01

    This study compares the rate of dislocation and revision for instability between 36-mm and anatomic femoral heads (large diameter metal-on-metal THA, dual-mobility bearings, and hip resurfacing arthroplasty) in patients at high risk for dislocation. A total of 501 high-risk patients, over a 10-year period, were identified (282 36-mm THA, 24 dual-mobility bearings, 83 metal-on-metal arthroplasty, and 112 hip resurfacing arthroplasty). There were 13 dislocations in the 36-mm group compared to 1 in the anatomic group (4.6% vs 0.5%; P = .005). Four patients dislocated more than once in the 36-mm group (1.4% vs 0%; P = .04), and 2 patients in the 36-mm group required a revision for instability (0.7% vs 0%; P = .11). These results suggest that anatomic head sizes significantly lower the risk of dislocation in high-risk patients. PMID:26360768

  11. Corneal Optical Quality Following Sub 1.8 mm Micro-Incision Cataract Surgery vs. 2.2 mm Mini-Incision Coaxial Phacoemulsification

    PubMed Central

    Alió, Jorge L.; Elkady, Bassam; Ortiz, Dolores

    2010-01-01

    Purpose: To study and compare the effects of the micro-incision cataract surgery (MICS-sub 1.8 mm) and miniincision coaxial phacoemulsification (2.2 mm) on the optical quality of the cornea characterized in terms of corneal aberrations. Materials and Methods: Fifty eyes underwent MICS and 50 mini-incision phacoemulsification, by the same surgeon. Both types of cataract surgery were performed using low ultrasound power and through a clear corneal incision, placed on the steepest corneal meridian ranging from 1.6 to 1.8 in MICS (Group I) and from 2.12 to 2.3 mm in mini-incision coaxial phacoemulsification (Group II). Seidel and Zernike aberration coefficients and RMS values were obtained for a 6-mm pupil preoperatively and one month after surgery. Results: The corneal astigmatism did not show statistically significant changes in either of the two groups: (MICS: –0.73 ± 0.63, –0.65 ± 0.53 D, P = 0.25), (mini-incision phacoemulsification; –1.21 ± 1.52, –1.00 ± 1.19 D, P = 0.12). The total RMS remained unchanged after MICS (1.77 ± 1.7, 1.65 ± 1.3 μm, P = 0.18) and mini-incision phacoemulsification (2.00 ± 1.87, 2.09 ± 1.8 μm, P = 0.41). Statistically significant changes were found for coma (P = 0.004) and higher-order aberrations (P < 0.001), showing MICS significantly less changes in cornea. Conclusions: Both MICS and mini-incision phacoemulsification do not degrade the optical quality of the cornea. Both surgeries do not induce a modification of the corneal astigmatism, even in the axis. It seems that 2 mm is the limit around which no optical changes are induced by cataract surgery in the human cornea. PMID:20543945

  12. Effects of pH adjustment with phosphates on attributes and functionalities of normal and high pH beef.

    PubMed

    Young, O A; Zhang, S X; Farouk, M M; Podmore, C

    2005-05-01

    Longissimus dorsi muscles from six normal- and six high-ultimate pH bulls were selected for fine mincing and subsequent pH adjustment with acid and alkaline pyrophosphate. Four pH treatments were prepared: initially high remains high (mean of pH 6.37), high becomes normal (5.62); initially normal remains normal (5.65), and normal becomes high (6.21). The addition level of phosphate as P(2)O(5) was the same in all replicates. Before pH adjustment, colour and water holding capacity (WHC) values were strongly affected by higher (initial) pH in expected ways: darker, lower chroma, higher capacity. After pH adjustment, these values were affected only by the final pH, not the initial pH (the pH history). Total protein solubility was likewise affected by final pH but not initial pH. In contrast, the combination high initial pH-high final pH improved sarcoplasmic protein solubility by 20% over the combination normal initial pH-high final pH. Sarcoplasmic protein solubility is an indicator of strain required to fracture cooked batters made from the minced meats; in the event, the rank order of the four treatments for strain-to-fracture matched that of sarcoplasmic protein solubility. Statistically, sarcoplasmic protein solubility and strain-to-fracture were both affected by initial pH (P<0.01) and final pH (P<0.001). However, stress required to fracture cooked batters was entirely controlled by initial pH (P<0.01). In other words, the stress-to-fracture advantage of initially high pH meat was not matched by upward pH adjustment of initially normal pH meat. Emulsion stability, which is better with higher pH meat, was affected by initial and final pH (both P<0.01). Cook yield, like WHC of pH-adjusted raw meat, was more due to final pH than initial pH, similarly cooked batter colour, whereas final pH had a significant effect on quality attributes (generally better when higher). An initially high pH history conferred an enduring advantage on three important batter attributes

  13. dMM-PBSA: A New HADDOCK Scoring Function for Protein-Peptide Docking

    PubMed Central

    Spiliotopoulos, Dimitrios; Kastritis, Panagiotis L.; Melquiond, Adrien S. J.; Bonvin, Alexandre M. J. J.; Musco, Giovanna; Rocchia, Walter; Spitaleri, Andrea

    2016-01-01

    Molecular-docking programs coupled with suitable scoring functions are now established and very useful tools enabling computational chemists to rapidly screen large chemical databases and thereby to identify promising candidate compounds for further experimental processing. In a broader scenario, predicting binding affinity is one of the most critical and challenging components of computer-aided structure-based drug design. The development of a molecular docking scoring function which in principle could combine both features, namely ranking putative poses and predicting complex affinity, would be of paramount importance. Here, we systematically investigated the performance of the MM-PBSA approach, using two different Poisson–Boltzmann solvers (APBS and DelPhi), in the currently rising field of protein-peptide interactions (PPIs), identifying the correct binding conformations of 19 different protein-peptide complexes and predicting their binding free energies. First, we scored the decoy structures from HADDOCK calculation via the MM-PBSA approach in order to assess the capability of retrieving near-native poses in the best-scoring clusters and of evaluating the corresponding free energies of binding. MM-PBSA behaves well in finding the poses corresponding to the lowest binding free energy, however the built-in HADDOCK score shows a better performance. In order to improve the MM-PBSA-based scoring function, we dampened the MM-PBSA solvation and coulombic terms by 0.2, as proposed in the HADDOCK score and LIE approaches. The new dampened MM-PBSA (dMM-PBSA) outperforms the original MM-PBSA and ranks the decoys structures as the HADDOCK score does. Second, we found a good correlation between the dMM-PBSA and HADDOCK scores for the near-native clusters of each system and the experimental binding energies, respectively. Therefore, we propose a new scoring function, dMM-PBSA, to be used together with the built-in HADDOCK score in the context of protein-peptide docking

  14. An efficient method of measuring the 4 mm helmet output factor for the Gamma Knife

    NASA Astrophysics Data System (ADS)

    Ma, Lijun; Li, X. Allen; Yu, Cedric X.

    2000-03-01

    It is essential to have accurate measurements of the 4 mm helmet output factor in the treatment of trigeminal neuralgia patients using the Gamma Knife. Because of the small collimator size and the sharp dose gradient at the beam focus, this measurement is generally tedious and difficult. We have developed an efficient method of measuring the 4 mm helmet output factor using regular radiographic films. The helmet output factor was measured by exposing a single Kodak XV film in the standard Leksell spherical phantom using the 18 mm helmet with 30-40 of its plug collimators replaced by the 4 mm plug collimators. The 4 mm helmet output factor was measured to be 0.876 ± 0.009. This is in excellent agreement with our EGS4 Monte Carlo simulated value of 0.876 ± 0.005. This helmet output factor value also agrees with more tedious TLD, diode and radiochromic film measurements that were each obtained using two separate measurements with the 18 mm helmet and the 4 mm helmet respectively. The 4 mm helmet output factor measured by the diode was 0.884 ± 0.016, and the TLD measurement was 0.890 ± 0.020. The radiochromic film measured value was 0.870 ± 0.018. Because a single-exposure measurement was performed instead of a double-exposure measurement, most of the systematic errors that appeared in the double-exposure measurements due to experimental setup variations were cancelled out. Consequently, the 4 mm helmet output factor is more precisely determined by the single-exposure approach. Therefore, routine measurement and quality assurance of the 4 mm helmet output factor of the Gamma Knife could be efficiently carried out using the proposed single-exposure technique.

  15. Cs diffusion in local Taiwan laterite with different solution concentration, pH and packing density.

    PubMed

    Wang, Tsing-Hai; Li, Ming-Hsu; Teng, Shi-Ping

    2008-09-01

    In this work we used an "in-diffusion" method to study the effects of pH, solution concentration and packing density on Cs diffusion by packing local Taiwan laterite (LTL) into modified capillary columns with 5mm diameter. These packed columns were first pre-equilibrated with synthetic groundwater (GW) for 3 weeks. The diffusion experiments were then carried out at ambient condition for 2 weeks. Our experimental results showed that the Cs diffusion profile fits Fick's second law very well in given experimental conditions, indicating the validity of modified capillary column method. Generally speaking, Cs diffusion in LTL decreases as the pH increases and as Cs concentration decreases. The apparent diffusion coefficient (D(a)) increases from 5.52 x 10(-12) (10(-7)M) to 2.18 x 10(-11) (10(-3)M)m(2)/s, while the effective diffusion coefficient (D(e)) shows slight variation as the Cs concentration changes. Both the derived D(a) and D(e) values decrease as the pH increases, implying that the diffusion mechanisms of Cs nuclide in alkaline and acid environment are different. In addition, our results show that Cs diffusion is unaffected by the given packing density, indicating the interlaminary space is not the major determinant of Cs adsorption and diffusion in LTL. PMID:18321721

  16. Depth Penetration and Detection of pH Gradients in Biofilms by Two-Photon Excitation Microscopy

    PubMed Central

    Vroom, Jurrien M.; De Grauw, Kees J.; Gerritsen, Hans C.; Bradshaw, David J.; Marsh, Philip D.; Watson, G. Keith; Birmingham, John J.; Allison, Clive

    1999-01-01

    Deep microbial biofilms are a major problem in many industrial, environmental, and medical settings. Novel approaches are needed to understand the structure and metabolism of these biofilms. Two-photon excitation microscopy (TPE) and conventional confocal laser scanning microscopy (CLSM) were compared quantitatively for the ability to visualize bacteria within deep in vitro biofilms. pH gradients within these biofilms were determined by fluorescence lifetime imaging, together with TPE. A constant-depth film fermentor (CDFF) was inoculated for 8 h at 50 ml · h−1 with a defined mixed culture of 10 species of bacteria grown in continuous culture. Biofilms of fixed depths were developed in the CDFF for 10 or 11 days. The microbial compositions of the biofilms were determined by using viable counts on selective and nonselective agar media; diverse mixed-culture biofilms developed, including aerobic, facultative, and anaerobic species. TPE was able to record images four times deeper than CLSM. Importantly, in contrast to CLSM images, TPE images recorded deep within the biofilm showed no loss of contrast. The pH within the biofilms was measured directly by means of fluorescence lifetime imaging; the fluorescence decay of carboxyfluorescein was correlated with biofilm pH and was used to construct a calibration curve. pH gradients were detectable, in both the lateral and axial directions, in steady-state biofilms. When biofilms were overlaid with 14 mM sucrose for 1 h, distinct pH gradients developed. Microcolonies with pH values of below pH 3.0 were visible, in some cases adjacent to areas with a much higher pH (>5.0). TPE allowed resolution of images at significantly greater depths (as deep as 140 μm) than were possible with CLSM. Fluorescence lifetime imaging allowed the in situ, real-time imaging of pH and the detection of sharp gradients of pH within microbial biofilms. PMID:10427041

  17. NhaP1 is a K+(Na+)/H+ antiporter required for growth and internal pH homeostasis of Vibrio cholerae at low extracellular pH

    PubMed Central

    Quinn, Matthew J.; Resch, Craig T.; Sun, Jonathan; Lind, Erin J.

    2012-01-01

    Vibrio cholerae has adapted to a wide range of salinity, pH and osmotic conditions, enabling it to survive passage through the host and persist in the environment. Among the many proteins responsible for bacterial survival under these diverse conditions, we have identified Vc-NhaP1 as a K+(Na+)/H+ antiporter essential for V. cholerae growth at low environmental pH. Deletion of the V. cholerae nhaP1 gene caused growth inhibition when external potassium was either limited (100 mM and below) or in excess (400 mM and above). This growth defect was most apparent at mid-exponential phase, after 4–6 h of culture. Using a pH-sensitive GFP, cytosolic pH was shown to be dependent on K+ in acidic external conditions in a Vc-NhaP1-dependent manner. When functionally expressed in an antiporterless Escherichia coli strain and assayed in everted membrane vesicles, Vc-NhaP1 operated as an electroneutral alkali cation/proton antiporter, exchanging K+ or Na+ ions for H+ within a broad pH range (7.25–9.0). These data establish the putative V. cholerae NhaP1 protein as a functional K+(Na+)/H+ antiporter of the CPA1 family that is required for bacterial pH homeostasis and growth in an acidic environment. PMID:22241048

  18. Fiber-optic pH sensor based on sol-gel film immobilized with neutral red

    NASA Astrophysics Data System (ADS)

    Jeon, Dayeong; Yoo, Wook Jae; Seo, Jeong Ki; Shin, Sang Hun; Han, Ki-Tek; Kim, Seon Geun; Park, Jang-Yeon; Lee, Bongsoo

    2013-03-01

    In this study, we developed a fiber-optic pH sensor based on a sol-gel film immobilized with neutral red (NR). A solgel film was prepared by mixing tetramethylorthosilicate (TMOS), trimethoxymethylsilane (MTMS), ethanol (EtOH), distilled water (H2O), and NR powder. Accordingly, the thin pH sol-gel film was fabricated through a sol-gel process with a dip-coating method. The thickness and diameter of the fabricated pH sol-gel film are 0.11 and 0.6 mm, respectively. We measured the optical absorbance and the light intensity with the spectra of reflected light, which change with the color variation of the pH sol-gel film in the fiber-optic sensing probe. From the experimental results, we demonstrated that the proposed fiber-optic pH sensor has good reversibility, reproducibility, and a fast response time, in which the optical properties of the NR-based pH sol-gel film change with the pH value.

  19. CALCULATION OF pKa IN PROTEINS WITH THE MICROENVIRONMENT MODULATED-SCREENED COULOMB POTENTIAL (MM-SCP)

    PubMed Central

    Shan, Jufang; Mehler, Ernest L.

    2011-01-01

    The MM-SCP has been applied to predict pKa values of titratable residues in wild type and mutants of staphylococcal nuclease (SNase). The calculations were based on crystal structures made available by the Garcia-Moreno Laboratory. In the mutants, mostly deeply buried hydrophobic residues were replaced with ionizable residues, and thus their pKa values could be measured and calculated using various methods. The data set used here consisted of a set of WT SNase for which His pKa at several ionic strengths had been measured, a set of mutants for which measured pKa were available and a set of 11 mutants for which the measured pKa were not known at the time of calculation. For this latter set, blind predictions were submitted to the protein pKa cooperative, 2009 workshop at Telluride, where the results of the blind predictions were discussed (the RMSD of the submitted set was 1.10 pH units). The calculations on the structures with known pKa indicated that in addition to weaknesses of the method, structural issues were observed that led to larger errors (>1) in pKa predictions. For example, different crystallography conditions or steric clashes can lead to differences in the local environment around the titratable residue, which can produce large differences in the calculated pKa. To gain further insight into the reliability of the MM-SCP, pKa of an extended set of 54 proteins belonging to several structural classes were carried out. Here some initial results from this study are reported to help place the SNase results in the appropriate context. PMID:21748803

  20. pH- and temperature-sensitive polymeric microspheres for drug delivery: the dissolution of copolymers modulates drug release.

    PubMed

    Fundueanu, Gheorghe; Constantin, Marieta; Stanciu, Cristina; Theodoridis, Georgios; Ascenzi, Paolo

    2009-12-01

    Most pH-/temperature-responsive polymers for controlled release of drugs are used as cross-linked hydrogels. However, the solubility properties of the linear polymers below and above the lower critical solution temperature (LCST) are not exploited. Here, the preparation and characterization of poly (N-isopropylacrylamide-co-methacrylic acid-co-methyl methacrylate) (poly (NIPAAm-co-MA-co-MM)) and poly (N-isopropylacrylamide-co-acrylamide) (poly (NIPAAm-co-AAm)), known as "smart" polymers (SP), is reported. Both poly (NIPAAm-co-MA-co-MM) and poly (NIPAAm-co-AAm) display pH- and temperature-responsive properties. Poly (NIPAAm-co-MA-co-MM) was designed to be insoluble in the gastric fluid (pH = 1.2), but soluble in the intestinal fluid (pH = 6.8 and 7.4), at the body temperature (37 degrees C). Poly (NIPAAm-co-AAm) was designed to have a lower critical solution temperature (LCST) corresponding to 37 degrees C at pH = 7.4, therefore it is not soluble above the LCST. The solubility characteristics of these copolymers were exploited to modulate the rate of release of drugs by changing pH and/or temperature. These copolymers were solubilized with hydrophobic cellulose acetate butyrate (CAB) and vitamin B(12) (taken as a water soluble drug model system) in an acetone/methanol mixture and dispersed in mineral oil. By a progressive evaporation of the solvent, the liquid droplets were transformed into loaded CAB/SP microspheres. Differential scanning calorimetric studies and scanning electron microscopy analysis demonstrated that the polymeric components of the microspheres precipitated separately during solvent evaporation forming small microdomains. Moreover, vitamin B(12) was found to be molecularly dispersed in both microdomains with no specific affinity for any polymeric component of microspheres. The release of vitamin B(12) was investigated as a function of temperature, pH, and the CAB/SP ratio. PMID:19562468

  1. The panacea toolbox of a PhD biomedical student.

    PubMed

    Skaik, Younis

    2014-01-01

    Doing a PhD (doctor of philosophy) for the sake of contribution to knowledge should give the student an immense enthusiasm through the PhD period. It is the time in one's life that one spends to "hit the nail on the head" in a specific area and topic of interest. A PhD consists mostly of hard work and tenacity; however, luck and genius might also play a little role. You can pass all PhD phases without having both luck and genius. The PhD student should have pre-PhD and PhD toolboxes, which are "sine quibus non" for getting successfully a PhD degree. In this manuscript, the toolboxes of the PhD student are discussed. PMID:25674150

  2. Suspected melanoma only when the lesion is greater than 6mm may harm patients

    PubMed Central

    de Oliveira, Renato Santos; de Oliveira, Daniel Arcuschin; Souza, Murilo Costa; da Silva, Mariane; Brandão, Mireille Darc Cavalcanti

    2015-01-01

    ABSTRACT Objective To analyze the distribution of larger diameter in the pathological report of cutaneous melanoma patients. Methods Data were obtained from patients seen from 1994 to 2015. Date, sex, age, maximum diameter, histological subtype, primary site, microscopic thickness, mitoses, ulceration, vertical growth phase, and regression were the variables studied. This study was approved by the National Ethics Committee - Brazil Platform. Patients were grouped into smaller diameter (≤6mm) and larger diameter (>6mm). The statistical analysis used the χ2 test (p<0.05). Results Of the 292 patients analyzed, 123 were seen between 1994 and 2004, and 169 between 2005 and 2015; in that, 151 women and 141 men, mean age of 52 years. The diameters ranged from 2 to 76mm (mean of 14mm), 81 patients with smaller diameter (≤6mm) and 211 with larger diameter (>6mm). Out of 81 patients with smaller diameter, 29 had invasive melanoma, while 179 of the 211 with larger diameter were invasive. A difference was observed in frequency of vertical growth phase. Conclusion Pigmented skin lesions with diameter smaller than 6mm should not be an excluding factor for biopsies, especially when patients present risk of developing skin cancer. PMID:26761547

  3. Toward Hamiltonian Adaptive QM/MM: Accurate Solvent Structures Using Many-Body Potentials.

    PubMed

    Boereboom, Jelle M; Potestio, Raffaello; Donadio, Davide; Bulo, Rosa E

    2016-08-01

    Adaptive quantum mechanical (QM)/molecular mechanical (MM) methods enable efficient molecular simulations of chemistry in solution. Reactive subregions are modeled with an accurate QM potential energy expression while the rest of the system is described in a more approximate manner (MM). As solvent molecules diffuse in and out of the reactive region, they are gradually included into (and excluded from) the QM expression. It would be desirable to model such a system with a single adaptive Hamiltonian, but thus far this has resulted in distorted structures at the boundary between the two regions. Solving this long outstanding problem will allow microcanonical adaptive QM/MM simulations that can be used to obtain vibrational spectra and dynamical properties. The difficulty lies in the complex QM potential energy expression, with a many-body expansion that contains higher order terms. Here, we outline a Hamiltonian adaptive multiscale scheme within the framework of many-body potentials. The adaptive expressions are entirely general, and complementary to all standard (nonadaptive) QM/MM embedding schemes available. We demonstrate the merit of our approach on a molecular system defined by two different MM potentials (MM/MM'). For the long-range interactions a numerical scheme is used (particle mesh Ewald), which yields energy expressions that are many-body in nature. Our Hamiltonian approach is the first to provide both energy conservation and the correct solvent structure everywhere in this system. PMID:27332140

  4. The Herschel Multi-Tiered Extragalactic Survey: SPIRE-mm Photometric Redshifts

    NASA Technical Reports Server (NTRS)

    Roseboom, I. G.; Ivison, R. J.; Greve, T. R.; Amblard, A.; Arumugam, V.; Auld, R.; Aussel, H.; Bethermin, M.; Blain, A.; Block, J.; Boselli, A.; Brisbin, D.; Buat, V.; Burgarella, D.; Castro-Rodriquez, N.; Cava, A.; Chanial, P.; Chapin, E.; Chapman, S.; Clements, D. L.; Conley, A.; Conversi, L.; Dowell, C. D.; Dunlop, J. S.; Dwek, E.

    2012-01-01

    We investigate the potential of submm-mm and submm-mm-radio photometric redshifts using a sample of mm-selected sources as seen at 250, 350 and 500 micron by the SPIRE instrument on Herschel. From a sample of 63 previously identified mm sources with reliable radio identifications in the Great Observatories Origins Deep Survey North and Lockman Hole North fields, 46 (73 per cent) are found to have detections in at least one SPIRE band. We explore the observed submm/mm color evolution with redshift, finding that the colors of mm sources are adequately described by a modified blackbody with constant optical depth Tau = (Nu/nu(sub 0))(exp Beta), where Beta = +1.8 and nu(sub 0) = c/100 micron. We find a tight correlation between dust temperature and IR luminosity. Using a single model of the dust temperature and IR luminosity relation, we derive photometric redshift estimates for the 46 SPIRE-detected mm sources. Testing against the 22 sources with known spectroscopic or good quality optical/near-IR photometric redshifts, we find submm/mm photometric redshifts offer a redshift accuracy of (absolute value of Delta sub (z))/(1 + z) = 0.16 (absolute value of Delta sub (z)) = 0.51). Including constraints from the radio-far-IR correlation, the accuracy is improved to (absolute value of Delta sub (z))/(1 + z) = 0.14 (((absolute value of Delta sub (z))) = 0.45). We estimate the redshift distribution of mm-selected sources finding a significant excess at Z > 3 when compared to approx 8S0 micron selected samples.

  5. The Herschel Multi-Tiered Extragalactic Survey: SPIRE-mm Photometric Redshifts

    NASA Technical Reports Server (NTRS)

    Roseboom, I. G.; Ivison, R. J.; Greve, T. R.; Amblard, A.; Arumugam, V.; Auld, R.; Aussel, H.; Bethermin, M.; Blain, A.; Bock, J.; Boselli, A.; Brisbin, D.; Buat, V.; Burgarella, D.; Castro-Rodriguez, N.; Cava, A.; Chanial, P.; Chapin, E.; Chapman, S.; Clements, D. L.; Conley, A.; Conversi, L.; Cooray, A.; Dowell, C. D.; Dwek, E.

    2011-01-01

    We investigate the potential of submm-mm and submm-mm-radio photometric red-shifts using a sample of mm-selected sources as seen at 250, 350 and 500 micrometers by the SPIRE instrument on Herschel. From a sample of 63 previously identified mm-sources with reliable radio identifications in the GOODS-N and Lockman Hole North fields 46 (73 per cent) are found to have detections in at least one SPIRE band. We explore the observed submm/mm colour evolution with redshift, finding that the colours of mm-sources are adequately described by a modified blackbody with constant optical depth Tau = (nu/nu(0))beta where beta = +1.8 and nu(0) = c/100 micrometers. We find a tight correlation between dust temperature and IR luminosity. Using a single model of the dust temperature and IR luminosity relation we derive photometric redshift estimates for the 46 SPIRE detected mm-sources. Testing against the 22 sources with known spectroscopic, or good quality optical/near-IR photometric, redshifts we find submm/mm photometric redshifts offer a redshift accuracy of |delta z|/(1+z) = 0.16 (less than |delta z| greater than = 0.51). Including constraints from the radio-far IR correlation the accuracy is improved to |delta z|/(1 + z) = 0.15 (less than |delta z| greater than = 0.45). We estimate the redshift distribution of mm-selected sources finding a significant excess at z greater than 3 when compared to 850 micrometer selected samples.

  6. [Sequence-specific interaction of pyrimidine oligonucleotides with double-stranded DNA at acidic pH complexes of different types].

    PubMed

    Brossalina, E B; Demchenko, E N; Demchenko, Iu N; Vlassov, V V

    2009-01-01

    The interaction of pyrimidine oligonucleotides (OLN(15) and OLN(6)) and their alkylating derivatives bearing 4-(3-amino)-N-methyl and N-2-chloroethyl (RCl) aniline residues at the 5'-phosphate with a fragment of the human gamma-interferon gene was studied. In the presence of 150 mM NaCl at pH 5.4, the yield of dsDNA alkylation was 60% for RCl-OLN(15) and 10% for RCl-OLN(6); at pH 4.0 in the presence of 150 mM NaCl and 10 mM MgCl2, the yield of the dsDNA modification product was 100% for RCl-OLN(6) and 50% for RCl-OLN(15). It was shown by native electrophoresis that OLN(15) could form with the target dsDNA complexes of two types in the presence of magnesium ions at pH 4.0. One of the complexes was stable at pH 5.4 in the presence of magnesium ions, whereas the other was not. We found that only the complex stable in 10 mM Mg(OAc)2, pH 5.4, was effectively alkylated. PMID:19915644

  7. Forces of interactions between bare and polymer-coated iron and silica: effect of pH, ionic strength, and humic acids.

    PubMed

    Pensini, Erica; Sleep, Brent E; Yip, Christopher M; O'Carroll, Denis

    2012-12-18

    The interactions between a silica substrate and iron particles were investigated using atomic force microscopy-based force spectroscopy (AFM). The micrometer- and nanosized iron particles employed were either bare or coated with carboxymethyl cellulose (CMC), a polymer utilized to stabilize iron particle suspensions. The effect of water chemistry on the forces of interaction was probed by varying ionic strength (with 100 mM NaCl and 100 mM CaCl₂) or pH (4, 5.5, and 8) or by introducing 10 mg/L of humic acids (HA). When particles were uncoated, the forces upon approach between silica and iron were attractive at pH 4 and 5.5 and in 100 mM CaCl₂ at pH 8, but they were negligible in 100 mM NaCl buffered to pH 8 and repulsive in water buffered to pH 8 and in HA solutions. HA produced electrosteric repulsion between iron particles and silica, likely due to its sorption to iron particles. HA sorption to silica was excluded on the basis of experiments conducted with a quartz-crystal microbalance with dissipation monitoring. Repulsion with CMC-coated iron was attributed to electrosteric forces, which were damped at high ionic strength. An extended DLVO model and a modified version of Ohshima's theory were successfully utilized to model AFM data. PMID:23163600

  8. Barium recovery by crystallization in a fluidized-bed reactor: effects of pH, Ba/P molar ratio and seed.

    PubMed

    Su, Chia-Chi; Reano, Resmond L; Dalida, Maria Lourdes P; Lu, Ming-Chun

    2014-06-01

    The effects of process conditions, including upward velocity inside the column, the amount of added seed and seed size, the pH value of the precipitant or the phosphate stream and the Ba/P molar ratio in a fluidized-bed reactor (FBR) were studied with a view to producing BaHPO₄ crystals of significant size and maximize the removal of barium. XRD were used to identify the products that were collected from the FBR. Experimental results show that an upward velocity of 48 cmmin(-1) produced the largest BaHPO₄ crystals with a size of around 0.84-1.0mm. The addition of seed crystals has no effect on barium removal. The use of a seed of a size in the ranges unseeded<0.149-0.29 mm<0.149 mm<0.29-0.42 mm produced increasing amounts of increasingly large crystals. The largest BaHPO₄ crystals were obtained at pH 8.4-8.8 with a Ba/P molar ratio of 1.0. In the homogeneous and heterogeneous processes, around 98% of barium was removed at pH 8.4-8.6 and [Ba]/[P]=1.0. The XRD results show that a significant amount of barium phosphate (Ba₃(PO₄)₂) was obtained at pH 11. The compounds BaHPO₄ and BaO were present at a pH of below 10. PMID:24462085

  9. Matching phosphate and maleate buffer systems for dissolution of weak acids: Equivalence in terms of buffer capacity of bulk solution or surface pH?

    PubMed

    Cristofoletti, Rodrigo; Dressman, Jennifer B

    2016-06-01

    The development of in vitro dissolution tests able to anticipate the in vivo fate of drug products has challenged pharmaceutical scientists over time, especially in the case of ionizable compounds. In the seminal model proposed by Mooney et al. thirty-five years ago, the pH at the solid-liquid interface (pH0) was identified as a key parameter in predicting dissolution rate. In the current work it is demonstrated that the in vitro dissolution of the weak acid ibuprofen in maleate and phosphate buffer systems is a function of the pH0, which in turn is affected by properties of the drug and the medium. The reported pH0 for ibuprofen dissolution in bicarbonate buffer, the predominant buffer species in the human small intestine under fasting conditions, can be achieved by reducing the phosphate buffer concentration to 5.0mM or the maleate buffer concentration to 2.2mM. Using this approach to identify the appropriate buffer/buffer capacity combination for in vitro experiments in FaSSIF-type media, it would be possible to increase the physiological relevance of this important biopharmaceutics tool. However, the necessity of monitoring and adjusting the bulk pH during the experiments carried out in 5.0mM phosphate or 2.2mM maleate buffers must also be taken into consideration. PMID:27032508

  10. Replacing 16-mm film cameras with high-definition digital cameras

    NASA Astrophysics Data System (ADS)

    Balch, Kris S.

    1995-09-01

    For many years 16 mm film cameras have been used in severe environments. These film cameras are used on Hy-G automotive sleds, airborne gun cameras, range tracking and other hazardous environments. The companies and government agencies using these cameras are in need of replacing them with a more cost effective solution. Film-based cameras still produce the best resolving capability, however, film development time, chemical disposal, recurring media cost, and faster digital analysis are factors influencing the desire for a 16 mm film camera replacement. This paper will describe a new camera from Kodak that has been designed to replace 16 mm high speed film cameras.

  11. Comparison of DFT and ab initio QM/MM methods for modelling reaction in chorismate synthase

    NASA Astrophysics Data System (ADS)

    Lawan, Narin; Ranaghan, Kara E.; Manby, Frederick R.; Mulholland, Adrian J.

    2014-07-01

    Quantum mechanics/molecular mechanics (QM/MM) methods are a popular tool in the investigation of enzyme reactions. Here, we compare B3LYP density functional theory (DFT) and ab initio QM/MM methods for modelling the conversion of 5-enolpyruvylshikimate-3-phosphate to chorismate in chorismate synthase. Good agreement with experimental data is only obtained at the SCS-MP2/CHARMM27 level for a reaction mechanism in which phosphate elimination precedes proton transfer. B3LYP predicts reaction energetics that are qualitatively wrong, stressing the need for ab initio QM/MM methods, and caution in interpretation of DFT results for this enzyme.

  12. G11.92–0.61-MM2: A BONAFIDE MASSIVE PRESTELLAR CORE?

    SciTech Connect

    Cyganowski, C. J.; Brogan, C. L.; Hunter, T. R.; Schnee, S.; Graninger, D.; Öberg, K. I.; Zhang, Q.; Vasyunin, A.; Friesen, R.

    2014-11-20

    Core accretion models of massive star formation require the existence of stable massive starless cores, but robust observational examples of such objects have proven elusive. We report subarcsecond-resolution Submillimeter Array (SMA) 1.3 mm, 1.1 mm, and 0.88 mm and Very Large Array 1.3 cm observations of an excellent massive starless core candidate, G11.92–0.61-MM2, initially identified in the course of studies of GLIMPSE Extended Green Objects (EGOs). Separated by ∼7.''2 from the nearby MM1 protostellar hot core, MM2 is a strong, compact dust continuum source (submillimeter spectral index α = 2.6 ± 0.1), but is devoid of star formation indicators. In contrast to MM1, MM2 has no masers, no centimeter continuum, and no (sub)millimeter wavelength line emission in ∼24 GHz of bandwidth observed with the SMA, including N{sub 2}H{sup +}(3-2), HCO{sup +}(3-2), and HCN(3-2). Additionally, there is no evidence for an outflow driven by MM2. The (sub)millimeter spectral energy distribution of MM2 is best fit with a dust temperature of ∼17-19 K and luminosity of ∼5-7 L {sub ☉}. The combined physical properties of MM2, as inferred from its dust continuum emission, are extreme: M ≳ 30 M {sub ☉} within a radius <1000 AU, N{sub H{sub 2}}>10{sup 25} cm{sup –2} and n{sub H{sub 2}} >10{sup 9} cm{sup –3}. Comparison of the molecular abundance limits derived from our SMA observations with gas-grain chemical models indicates that extremely dense (n(H) >> 10{sup 8} cm{sup –3}), cold (<20 K) conditions are required to explain the lack of observed (sub)millimeter line emission, consistent with the dust continuum results. Our data suggest that G11.92–0.61-MM2 is the best candidate for a bonafide massive prestellar core found to date, and a promising target for future higher-sensitivity observations.

  13. Recent Ph.D.s; Honors

    NASA Astrophysics Data System (ADS)

    2005-04-01

    Recent Ph.D.s. Atmospheric Sciences. A study of atmospheric ammonia in coastal ecosystems utilizing relaxed eddy accumulation techniques and ion mobility spectrometry, LaToya Myles, Florida A&M University, December 2004, Advisor: Larry Robinson. Honors. Rana A. Fine has been awarded the 2005 Provost Award for Scholarly Activity, presented by the University of Miami. The award ``recognizes faculty for extraordinary research and scholarly pursuits.'' Charles David Keeling and Lonnie G. Thompson will receive the 2005 Tyler Prize for Environmental Achievement. The prize is given to individuals whose accomplishments in environmental science, policy, energy, and medicine confer great benefit upon mankind.

  14. Toxicity evaluation of pH dependent stable Achyranthes aspera herbal gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Tripathi, Alok; Kumari, Sarika; Kumar, Arvind

    2016-01-01

    Nanoparticles have gained substantial attention for the control of various diseases. However, any adverse effect of herbal gold nanoparticles (HGNPs) on animals including human being has not been investigated in details. The objectives of current study are to assess the cytotoxicity of HGNPs synthesized by using leaf extract of Achyranthes aspera, and long epoch stability. The protocol deals with stability of HGNPs in pH dependent manner. Visually, HGNPs formation is characterized by colour change of extract from dark brown to dark purple after adding gold chloride solution (1 mM). The 100 μg/ml HGNPs concentration has been found nontoxic to the cultured spleenocyte cells. Spectrophotometric analysis of nanoparticles solution gave a peak at 540 nm which corresponds to surface plasmon resonance absorption band. As per scanning electron microscopy and Transmission electron microscopy (TEM), size of HGNPs are in the range of 50-80 nm (average size 70 nm) with spherical morphology. TEM-selected area electron diffraction observation showed hexagonal texture. HGNPs showed substantial stability at higher temperature (85 °C), pH 10 and salt concentration (5 M). The zeta potential value of HGNPs is -35.9 mV at temperature 25 °C, pH 10 showing its good quality with better stability in comparison to pH 6 and pH 7. The findings advocate that the protocol for the synthesis of HGNPs is easy and quick with good quality and long epoch stability at pH 10. Moreover, non-toxic dose could be widely applicable for human health as a potential nano-medicine in the future to cure diseases.

  15. Exchangeable hydrogen explains the pH of spodosol Oa horizons

    USGS Publications Warehouse

    Ross, D.S.; David, M.B.; Lawrence, G.B.; Bartlett, R.J.

    1996-01-01

    The chemistry of extremely acid Oa horizons does not conform to traditional pH, Al, and base saturation relationships. Results from two separate studies of northeastern U.S. forested soils were used to investigate relationships between pH in water or dilute salt solutions and other soil characteristics. In Oa horizons with pH below 4, soil pH in dilute CaCl2 solution was correlated with exchangeable H+ measured either by titration (r = -0.88, P = 0.0001, n = 142) or by electrode (r = -0.89, P = 0.0001, n = 45). Exchangeable H+ expressed as a percentage of the cation-exchange capacity (CEC) was linear with pH and showed similar slopes for data from both studies. For all samples, pHw = 4.21 - 1.80 x H+/CEC (R2 = 0.69, n = 194). The reciprocal of the H+/CEC ratio is base saturation with Al added to the bases. Because of the low pH, exchangeable Al does not appear to behave as an acid. Exchangeable H+ remains an operationally defined quantity because of the difficulty in separating exchange and hydrolysis reactions. In a variety of neutral-salt extractants, concentration of H+ were correlated with 0.1 M BaCl2-exchangeable H+ (r > 0.91, P = 0.0001, n = 26) regardless of the strength of the extract. Nine successive extractions with 0.33 mM CaCl2 removed more H+ than was removed by single batch extractions with either 1 M KCl or 0.1 M BaCl2 (average H+ of 70, 43, and 49 mmol kg-1, respectively for 26 samples). The data showed little difference in the chemical behavior of Oa horizons from a variety of geographical sites and vegetation types.

  16. Somatic embryogenesis of carrot in hormone-free medium: external pH control over morphogenesis

    NASA Technical Reports Server (NTRS)

    Smith, D. L.; Krikorian, A. D.

    1990-01-01

    Cultures of preglobular stage proembryos (PGSPs) were initiated from mechanically wounded mature zygotic embryos of carrot, Daucus carota, on a hormone-free, semisolid medium. These PGSPs have been maintained and multiplied for extended periods without their progression into later embryo stages on the same hormone-free medium containing 1 mM NH4+ as the sole nitrogen source. Sustained maintenance of cultures comprised exclusively of PGSPs was dependent on medium pH throughout the culture period. Best growth and multiplication of PGSP cultures occurred when the pH of unbuffered, hormone-free medium fell from 4.5 to 4 over a 2-week period or when buffered medium was titrated to pH 4. If the hormone-free medium was buffered to sustain a pH at or above 4.5, PGSPs developed into later embryo stages. Maintenance with continuous multiplication of PGSPs occurred equally well on medium containing NH4+ or NH4+ and NO3-, but growth was poor with NO3- alone. Additional observations on the effects of medium components such as various nitrogen sources and levels, sucrose concentration, semisolid supports, type of buffer, borate concentration, activated charcoal, and initial pH that permit optimum maintenance of the PGSPs or foster their continued developmental progression into mature embryos and plantlets are reported. The influence of the pH of the hormone-free medium as a determinant in maintaining cultures as PGSPs or allowing their continued embryonic development are unequivocally demonstrated by gross morphology, scanning electron microscopy, and histological preparations.

  17. Seeding-dependent maturation of beta2-microglobulin amyloid fibrils at neutral pH.

    PubMed

    Kihara, Miho; Chatani, Eri; Sakai, Miyo; Hasegawa, Kazuhiro; Naiki, Hironobu; Goto, Yuji

    2005-03-25

    Beta2-microglobulin (beta2-m) is a major component of amyloid fibrils deposited in patients with dialysis-related amyloidosis. Recent studies have focused on the mechanism by which amyloid fibrils are formed under physiological conditions, which had been difficult to reproduce quantitatively. Yamamoto et al. (Yamamoto, S., Hasegawa, K., Yamaguchi, I., Tsutsumi, S., Kardos, J., Goto, Y., Gejyo, F. & Naiki, H. (2004) Biochemistry 43, 11075-11082) showed that a combination of seed fibrils prepared under acidic conditions and a low concentration of sodium dodecyl sulfate below its critical micelle concentration enabled extensive fibril formation at pH 7.0. Here, we found that repeated self-seeding at pH 7.0 with fibrils formed at the same pH causes a marked acceleration of growth, indicating the maturation of fibrils. The observed maturation can be simulated by assuming the existence of two types of fibrils with different growth rates. Importantly, some mutations of beta2-m or the addition of a low concentration of urea, both destabilizing the native conformation, were not enough to extend the fibrils at pH 7.0, and a low concentration of sodium dodecyl sulfate (i.e. 0.5 mM) was essential. Thus, even though the first stage fibrils in patients are unstable and require stabilizing factors to remain at neutral pH, they can adapt to a neutral pH with repeated self-seeding, implying a mechanism of development of amyloid deposition after a long latent period in patients. PMID:15659393

  18. Hybrid Laser-arc Welding of 17-4 PH Martensitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Ma, Junjie; Atabaki, Mehdi Mazar; Pillai, Raju; Kumar, Biju; Vasudevan, Unnikrishnan; Sreshta, Harold; Kovacevic, Radovan

    2015-06-01

    17-4 PH stainless steel has wide applications in severe working conditions due to its combination of good corrosion resistance and high strength. The weldability of 17-4 PH stainless steel is challenging. In this work, hybrid laser-arc welding was developed to weld 17-4 PH stainless steel. This method was chosen based on its advantages, such as deep weld penetration, less filler materials, and high welding speed. The 17-4 PH stainless steel plates with a thickness of 19 mm were successfully welded in a single pass. During the hybrid welding, the 17-4 PH stainless steel was immensely susceptible to porosity and solidification cracking. The porosity was avoided by using nitrogen as the shielding gas. The nitrogen stabilized the keyhole and inhibited the formation of bubbles during welding. Solidification cracking easily occurred along the weld centerline at the root of the hybrid laser-arc welds. The microstructural evolution and the cracking susceptibility of 17-4 PH stainless steel were investigated to remove these centerline cracks. The results showed that the solidification mode of the material changed due to high cooling rate at the root of the weld. The rapid cooling rate caused the transformation from ferrite to austenite during the solidification stage. The solidification cracking was likely formed as a result of this cracking-susceptible microstructure and a high depth/width ratio that led to a high tensile stress concentration. Furthermore, the solidification cracking was prevented by preheating the base metal. It was found that the preheating slowed the cooling rate at the root of the weld, and the ferrite-to-austenite transformation during the solidification stage was suppressed. Delta ferrite formation was observed in the weld bead as well no solidification cracking occurred by optimizing the preheating temperature.

  19. Noninvasive NIR measurement of tissue pH to assess hemorrhagic shock in swine

    NASA Astrophysics Data System (ADS)

    Soller, Babs R.; Zhang, Songbiao; Micheels, Ronald H.; Puyana, Juan C.

    1999-07-01

    Body-worn noninvasive physilogical sensors are needed to continuously monitor soldiers for hemorrhage and to provide real-time information for minimally skilled medics to treat the injured. In the hospital intramucosal pHi of the gut is used to monitor shock and its treatment. We hypothesize that abdominal wall muscle (AWM) pH can be measured noninvasively using near infrared (NIR) spectroscopy and partial least squares analysis (PLS) and will correlate with pHi. METHODS: AWM pH was measured with microelectrodes and gastric pHi was measured with a tonometric catheter simultaneously while NIR spectra were collected using prototype LED spectrometers placed on the pig's flanks. Animals were subject to hemorrhagic shock at 45 mm Hg for 45 minutes, then resuscitated with blood and lactated ringers. Relationships between electrode pH, pHi and NIR spectra were developed using PLS with cross validation. RESULTS: NIR spectral changes noninvasively acquired through the skin were shown to be from the muscle, not from changes in skin blood flow. Trending ability (R2) model accuracy (RMSD), and relative error were calculated for individual pigs. Using electrode pH as the reference, average R2 was 0.88 with a predicted accuracy of 0.17 pH units, a 9.3% relative error. Slightly degraded results were observed when pHi was used as a reference. CONCLUSIONS: NIR measurement of tissue pH can be used to noninvasively monitor for shock and guide its treatment in a swine model. These measurements correlate with gastric pHi, a clinically accepted measure of shock, providing an approach to develop similar methodology for humans.

  20. Novel spin-coating technology for 248-nm/193-nm DUV lithography and low-k spin on dielectrics of 200-mm/300-mm wafers

    NASA Astrophysics Data System (ADS)

    Gurer, Emir; Zhong, Tom X.; Lewellen, John W.; Lee, Ed C.

    2000-06-01

    An alternative coating technology was developed for 248 nm/193 nm DUV lithography and low-k spin on dielectric (SOD) materials used in the interconnect area. This is a 300 mm enabling technology which overcomes turbulent flow limitations above 2000 rpm and it prevents 40 - 60% reduction on the process latitudes of evaporation-related variables, common to 300 mm conventional coaters. Our new coating technology is fully enclosed and it is capable of controlling the solvent concentration above the resist film dynamically in the gas phase. This feature allows a direct control of the evaporation mass transfer which determines the quality of the final resist profiles. Following process advantages are reported in this paper: (1) Demonstrated that final resist film thickness can be routinely varied by 4000 angstrom at a fixed drying spin speed, thus minimizing the impact of turbulence wall for 300 mm wafers. (2) Evaporation control allows wider range of useful thickness from a fixed viscosity material. (3) Latitudes of evaporation-related process variables is about 40% larger than that of a conventional coater. (4) Highly uniform films of 0.05% were obtained for 8800 angstrom target thickness with tighter wafer-wafer profile control because of the enclosed nature of the technology. (5) Dynamic evaporation control facilitates resist consumption minimization. Preliminary results indicate feasibility of a 0.4 cc process of record (POR) for a 200 mm substrate. (6) Lower COO due to demonstrated relative insensitivity to environmental variables, robust resist consumption minimization and superior process capabilities. (7) Improved planarization and gap fill properties for the new generation photoresist/low-k SOD materials deposited using this enclosed coating technology.

  1. Assessment of Salivary Flow Rate and pH Among Areca Nut Chewers and Oral Submucous Fibrosis Subjects: A Comparative Study

    PubMed Central

    Abdul Khader, Nishat Fatima; Dyasanoor, Sujatha

    2015-01-01

    Background: To assess and compare the salivary flow rate (SFR) and salivary pH among areca nut chewers, oral submucous fibrosis (OSMF) patients and apparently healthy individuals. Methods: A comparative study was conducted to assess and compare the SFR and pH among 135 outpatients (45 areca nut chewers + 45 OSMF + 45 control) at The Oxford Dental College and Research Hospital, Bangalore, India. Subjects were interviewed using structural proforma and Modified Schirmer strips and pH paper were implemented for assessing SFR and pH respectively. Statistical analysis was done using IBM SPSS ver. 21.0 software. Results: A statistically significant increase in SFR (35.7 mm at 3rd minutes) among areca nut group and a decrease in SFR among OSMF group (23.4 mm at 3rd minutes) when compared to apparently healthy subjects (30.7 mm at 3rd minutes). The mean pH among areca nut, OSMF and control groups was 6.76, 6.82, and 6.74 respectively with no statistical significance. Conclusions: The observation and findings of the study clearly showed hypersalivation among areca nut group and hyposalivation among OSMF group, with no significant change in salivary pH when compared to healthy subjects. PMID:26473160

  2. Docking modes of BB-3497 into the PDF active site--a comparison of the pure MM and QM/MM based docking strategies.

    PubMed

    Kumari, Tripti; Issar, Upasana; Kakkar, Rita

    2014-01-01

    Peptide deformylase (PDF) has emerged as an important antibacterial drug target. Considerable effort is being directed toward developing peptidic and non-peptidic inhibitors for this metalloprotein. In this work, the known peptidic inhibitor BB-3497 and its various ionization and tautomeric states are evaluated for their inhibition efficiency against PDF using a molecular mechanics (MM) approach as well as a mixed quantum mechanics/molecular mechanics (QM/MM) approach, with an aim to understand the interactions in the binding site. The evaluated Gibbs energies of binding with the mixed QM/MM approach are shown to have the best predictive power. The experimental pose is found to have the most negative Gibbs energy of binding, and also the smallest strain energy. A quantum mechanical evaluation of the active site reveals the requirement of strong chelation by the ligand with the metal ion. The investigated ligand chelates the metal ion through the two oxygens of its reverse hydroxamate moiety, particularly the N-O(-) oxygen, forming strong covalent bonds with the metal ion, which is penta-coordinated. In the uninhibited state, the metal ion is tetrahedrally coordinated, and hence chelation with the inhibitor is associated with an increase of the metal ion coordination. Thus, the strong binding of the ligand at the binding site is accounted for. PMID:25994638

  3. Effect of pH on the accumulation kinetics of pentachlorophenol in goldfish

    USGS Publications Warehouse

    Stehly, G.R.; Hayton, W.L.

    1990-01-01

    The kinetics of accumulation of pentachlorophenol (PCP) at various pH values were investigated to explore how pH-dependent accumulation might influence PCP toxicity. Goldfish (Carassius auratus ) were exposed to 5 mu g PCP/L in a static system buffered with 7.5 mM bicine or N,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid (BES) at pH 7.0, 8.0, or 9.0. The amount of PCP in the fish, concentration of PCP in water, and the total amount of metabolites in the system were measured after exposure of fish from 1 to 96 hr. The distribution of PCP within the fish was altered by changes in the external pH. The pH-associated changes in distribution may have altered access of PCP to sites of metabolism, thereby altering the metabolic clearance. The pH-related changes in the pharmacokinetics of PCP resulted in a decrease in its bioconcentration factor with an increase in pH and account both for the decreased capacity of the fish to accumulated PCP and for its reduced LC50.

  4. Hydrogen-bond network and pH sensitivity in human transthyretin

    PubMed Central

    Yokoyama, Takeshi; Mizuguchi, Mineyuki; Nabeshima, Yuko; Kusaka, Katsuhiro; Yamada, Taro; Hosoya, Takaaki; Ohhara, Takashi; Kurihara, Kazuo; Tanaka, Ichiro; Niimura, Nobuo

    2013-01-01

    Transthyretin (TTR) is a tetrameric protein. TTR misfolding and aggregation are associated with human amyloid diseases. Dissociation of the TTR tetramer is believed to be the rate-limiting step in the amyloid fibril formation cascade. Low pH is known to promote dissociation into monomer and the formation of amyloid fibrils. In order to reveal the molecular mechanisms underlying pH sensitivity and structural stabilities of TTR, neutron diffraction studies were conducted using the IBARAKI Biological Crystal Diffractometer with the time-of-flight method. Crystals for the neutron diffraction experiments were grown up to 2.5 mm3 for four months. The neutron crystal structure solved at 2.0 Å revealed the protonation states of His88 and the detailed hydrogen-bond network depending on the protonation states of His88. This hydrogen-bond network is involved in monomer–monomer and dimer–dimer interactions, suggesting that the double protonation of His88 by acidification breaks the hydrogen-bond network and causes the destabilization of the TTR tetramer. Structural comparison with the X-ray crystal structure at acidic pH identified the three amino acid residues responsible for the pH sensitivity of TTR. Our neutron model provides insights into the molecular stability related to amyloidosis. PMID:24121323

  5. Simple Evaluation Method of Atmospheric Plasma Irradiation Dose using pH of Water

    NASA Astrophysics Data System (ADS)

    Koga, Kazunori; Sarinont, Thapanut; Amano, Takaaki; Seo, Hyunwoong; Itagaki, Naho; Nakatsu, Yoshimichi; Tanaka, Akiyo; Shiratani, Masaharu

    2015-09-01

    Atmospheric discharge plasmas are promising for agricultural productivity improvements and novel medical therapies, because plasma provides high flux of short-lifetime reactive species at low temperature, leading to low damage to living body. For the plasma-bio applications, various kinds of plasma systems are employed, thus common evaluation methods are needed to compare plasma irradiation dose quantitatively among the systems. Here we offer simple evaluation method of plasma irradiation dose using pH of water. Experiments were carried out with a scalable DBD device. 300 μl of deionized water was prepared into the quartz 96 microwell plate at 3 mm below electrode. The pH value has been measured just after 10 minutes irradiation. The pH value was evaluated as a function of plasma irradiation dose. Atmospheric air plasma irradiation decreases pH of water with increasing the dose. We also measured concentrations of chemical species such as nitrites, nitrates and H2O2. The results indicate our method is promising to evaluate plasma irradiation dose quantitatively.

  6. Synchronous Bioimaging of Intracellular pH and Chloride Based on LSS Fluorescent Protein.

    PubMed

    Paredes, Jose M; Idilli, Aurora I; Mariotti, Letizia; Losi, Gabriele; Arslanbaeva, Lyaysan R; Sato, Sebastian Sulis; Artoni, Pietro; Szczurkowska, Joanna; Cancedda, Laura; Ratto, Gian Michele; Carmignoto, Giorgio; Arosio, Daniele

    2016-06-17

    Ion homeostasis regulates critical physiological processes in the living cell. Intracellular chloride concentration not only contributes in setting the membrane potential of quiescent cells but it also plays a role in modulating the dynamic voltage changes during network activity. Dynamic chloride imaging demands new tools, allowing faster acquisition rates and correct accounting of concomitant pH changes. Joining a long-Stokes-shift red-fluorescent protein to a GFP variant with high sensitivity to pH and chloride, we obtained LSSmClopHensor, a genetically encoded fluorescent biosensor optimized for the simultaneous chloride and pH imaging and requiring only two excitation wavelengths (458 and 488 nm). LSSmClopHensor allowed us to monitor the dynamic changes of intracellular pH and chloride concentration during seizure like discharges in neocortical brain slices. Only cells with tightly controlled resting potential revealed a narrow distribution of chloride concentration peaking at about 5 and 8 mM, in neocortical neurons and SK-N-SH cells, respectively. We thus showed that LSSmClopHensor represents a new versatile tool for studying the dynamics of chloride and proton concentration in living systems. PMID:27031242

  7. Acceleration of pH variation in cloudy apple juice using electrodialysis with bipolar membranes.

    PubMed

    Lam Quoc, A; Lamarche, F; Makhlouf, J

    2000-06-01

    The purpose of this study was to accelerate pH variation in cloudy apple juice using electrodialysis (ED). The testing was conducted using two ED configurations. The bipolar and cationic membrane configuration showed that reducing the spacing from 8 to 0.75 mm had little effect on treatment time, whereas stacking eight bipolar membranes reduced acidification time by 30%, although the treatment still took too long (21 min). Furthermore, it was not possible to acidify apple juice to a pH of 2.0 to completely inhibit enzymatic browning. The bipolar and anionic membrane configuration helped to accelerate the acidification step by a factor of 3, increasing the yield from 3.3 to 10 L of juice/m(2) membrane/min. Moreover, treatment time was inversely proportional to the size of the membrane stack. The speed at which the pH of acidified juice returned to its initial value was, however, 4 times slower than the speed of acidification, giving a yield of 2.5 L of juice/m(2) membrane/min. By accelerating the acidification step, ED treatment with bipolar and anionic membranes results in more effective polyphenol oxidase activity and more rapid control of juice browning at pH 2.0. Also, the treatment has very little effect on the chemical composition and organoleptic quality of apple juice. PMID:10888515

  8. Thymol blue immobilized on tapered fibers as optical transducer for pH sensing

    NASA Astrophysics Data System (ADS)

    Baldini, Francesco; Ciaccheri, Leonardo; Falai, Alida; Mignani, Anna G.; Rayss, Jan; Sudolski, Grzegorz

    1999-02-01

    The present work is concerned with the optical characterization of an evanescent wave sensor for pH detection. First, the interaction between the solution containing the acid-base indicator and the fiber core was investigated. Then, the acid-base indicator, thymol blue, was covalently immobilized on the core of a 200/380 micrometers fiber by means of a silylation process of the glass surface. The fiber core surface was modified along a section of 8 mm. A comparison was made using both bare and tapered fibers, with a tapering ratio (fiber diameter/waist diameter) of 2.3. An enhancement in sensitivity of a factor 6 was observed with tapered fibers in the 1/2.5 range, and a sensitivity of 0.05 pH units was attained.

  9. Interstitial PCO2 and pH, and their role as chemostimulants in the isolated respiratory network of neonatal rats.

    PubMed Central

    Voipio, J; Ballanyi, K

    1997-01-01

    1. CO2-H(+)-sensitive microelectrodes were used for simultaneous measurements of the partial pressure of CO2 (PCO2) and extracellular pH (pHo) in the ventral respiratory group (VRG) of the isolated brainstem-spinal cord of neonatal rats. Some of the data were analysed using diffusion equations. 2. With increasing recording depth within the boundaries of the VRG (300-600 microns below the tissue surface), PCO2 increased from 77 to 95 mmHg and pHo fell from 7.0 to 6.8 at steady state in standard saline equilibrated with 5% CO2 and 95% O2. 3. Elevating bath CO2 from 5 to 10-12.5% produced a mean increase in PCO2 of 18 mmHg, a fall in pHo of 0.13 pH units, and a 50-250% increase in the frequency of respiration-related spinal (C2) nerve bursts. Similar effects on C2 activity and pHo were observed upon lowering bath [HCO3-] from 25 to 10 mM, leading to a mean decrease in PCO2 of 4.4 mmHg in the VRG. 4. Raising bath [HCO3-] to 50 mM produced a substantial frequency decrease, a rise in pHo of 0.24 pH units and an elevation in PCO2 of 9.3 mmHg. C2 activity was not profoundly affected upon doubling the CO2-HCO3- content, leading to a mean increase in pHo of 0.13 pH units and elevation of PCO2 by 30 mmHg. 5. In a CO2-HCO3(-)-free, Hepes-buffered solution, PCO2 decreased to 18 mmHg in the VRG and pHo fell by 0.15 pH units with no major effect on rhythmic activity. Subsequent anoxic exposure for more than 15 min produced a further fall in PCO2 to below 1 mmHg, a decrease in pHo of 0.55 pH units, and blockade of respiration-related activity. In three out of the six preparations tested, C2 activity could be restored by reapplication of CO2-HCO3- in the absence of O2. 6. C2 activity persisted at a reduced frequency, even up to 30 min, during anoxia in the CO2-HCO(-)-buffered saline,leading to an elevation in PCO2 of 15 mmHg and a fall in pHo of 0.18 pH units. 7. The diffusion coefficient of CO2 in the tissue was found to be equal to that in saline. Two mean estimates for anoxic

  10. Adaptive Partitioning QM/MM Dynamics Simulations for Substrate Uptake, Product Release, and Solvent Exchange.

    PubMed

    Duster, A; Garza, C; Lin, H

    2016-01-01

    Combined quantum mechanics/molecular mechanics (QM/MM) plays an important role in multiscale simulations of biological systems including enzymes. The adaptive-partitioning (AP) schemes surpass the conventional QM/MM methods in that they allow the on-the-fly, smooth exchange of particles between QM and MM subsystems in molecular dynamics simulations, leading to a seamless and dynamic integration of the QM and MM realms. Originally developed for simulating ion solvation in bulk solutions, the AP schemes have recently been extended to the treatment of proteins, fostering applications in the simulations of enzymes. The present contribution provides a detailed account of the AP schemes. We delineate the background of the algorithms and their parallel implementation, as well as offer practical advice and examples for their applications in the simulations of biological systems. PMID:27498644

  11. Light-controlled photonics-based mm-wave beam switch.

    PubMed

    Yurchenko, Vladimir; Ciydem, Mehmet; Gradziel, Marcin; Murphy, Anthony; Altintas, Ayhan

    2016-07-25

    We present experimental investigation of light-controlled photonics-enhanced quasi-optical mm-wave beam switch operating at a resonant frequency in the mm-wave band of 75 to 110 GHz. The switch is implemented as a Bragg structure with a resonant layer of high-resistivity silicon that creates a narrow transmission peak within the mm-wave propagation gap. The peak amplitude is sensitive to the intensity of light pulses illuminating the structure. When using a silicon wafer of 30 KOhm · cm resistivity and light pulses created by a 400W LED-array light source, we achieved mm-wave transmission peak modulation exceeding 15 dB. PMID:27464100

  12. CD Reference Materials Fabricated on Monolithic 200 mm Wafers for Automated Metrology Tool Applications

    NASA Astrophysics Data System (ADS)

    Allen, Richard A.; Dixson, Ronald G.; Cresswell, Michael W.; Guthrie, William F.; Shulver, Byron J. R.; Bunting, A. S.; Stevenson, J. T. M.; Walton, Anthony J.

    2007-09-01

    Recently, prototype isolated-line, single-crystal critical dimension (CD) reference materials (SCCDRMs) with linewidths as narrow as 40 nm±1.5 nm have been reported. These reference materials, designated NIST Prototype Reference Material (RM) 8111, were configured as 10 mm by 11 mm silicon test chips mounted in 200 mm carrier wafers. The RM 8111 chips were fabricated using microelectromechanical (MEMS) process techniques, which assure the alignment of the sidewalls of the features to silicon (111) lattice planes, and were calibrated in a sequence involving atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM) metrology. This paper reports initial results on SCCDRMs fabricated on 200 mm bulk wafers; this monolithic approach would eliminate the need for carrier wafers.

  13. 19. Southeast end room; view to southeast, 65mm lens plus ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. Southeast end room; view to southeast, 65mm lens plus electronic flash illumination. Note extent of failure; figure for scale. - Benicia Arsenal, Powder Magazine No. 5, Junction of Interstate Highways 680 & 780, Benicia, Solano County, CA

  14. 5. East portal of Tunnel 26, view to southwest, 135mm ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. East portal of Tunnel 26, view to southwest, 135mm lens. Tunnel 25 (HAER CA-201) is visible in the distance. - Central Pacific Transcontinental Railroad, Tunnel No. 26, Milepost 133.29, Applegate, Placer County, CA

  15. 480mm telephoto perpective, looking south toward midspan and south anchor ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    480-mm telephoto perpective, looking south toward mid-span and south anchor arm. - Pittsburgh & Lake Erie Railroad, Ohio River Bridge, Spanning Ohio River, West of Beaver River, Beaver, Beaver County, PA

  16. 480mm telephoto perspective, looking south toward midspan and south anchor ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    480-mm telephoto perspective, looking south toward mid-span and south anchor arm. - Pittsburgh & Lake Erie Railroad, Ohio River Bridge, Spanning Ohio River, West of Beaver River, Beaver, Beaver County, PA

  17. Same-source parallel implementation of the PSU/NCAR MM5

    SciTech Connect

    Michalakes, J.

    1997-12-31

    The Pennsylvania State/National Center for Atmospheric Research Mesoscale Model is a limited-area model of atmospheric systems, now in its fifth generation, MM5. Designed and maintained for vector and shared-memory parallel architectures, the official version of MM5 does not run on message-passing distributed memory (DM) parallel computers. The authors describe a same-source parallel implementation of the PSU/NCAR MM5 using FLIC, the Fortran Loop and Index Converter. The resulting source is nearly line-for-line identical with the original source code. The result is an efficient distributed memory parallel option to MM5 that can be seamlessly integrated into the official version.

  18. VIEW OF KENNEDY AVIONICS TEST SET LABORATORY, ROOM NO. MM6, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF KENNEDY AVIONICS TEST SET LABORATORY, ROOM NO. MM6, FACING NORTH - Cape Canaveral Air Force Station, Launch Complex 39, Vehicle Assembly Building, VAB Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

  19. Parameters of tensile strength, elongation, and tenacity of 70mm IIaO spectroscopic film

    NASA Technical Reports Server (NTRS)

    Hammond, Ernest C., Jr.; Peters, Kevin A.

    1989-01-01

    The 70mm IIaO spectroscopic film was tested to determine its tensile strength, elongation, and breaking strength, using an Instron (strength and compression) 4201 Test Instrument. These data provide information leading to the upper and lower limits of the above parameters for 70mm IIaO spectroscopic film. This film will be developed by a commercial developing machine after the Ultraviolet Telescope Space Shuttle Mission returns to the Earth in the early 1990's; thus, it is necessary to understand these force parameters. Several test strips of approximately 200mm in length were used. The results indicate that when a stress load of 100 kg was applied, the film elongated approximately 1.06mm and the break strength was 19.45 kilograms.

  20. 7. Detail, east portal of Tunnel 34/Snowshed 33, 135mm lens. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Detail, east portal of Tunnel 34/Snowshed 33, 135mm lens. Tall signal mast necessary in order to be seen above winter snows. - Central Pacific Transcontinental Railroad, Tunnel No. 41, Milepost 193.3, Donner, Placer County, CA

  1. 18. Southeast end room; view to northeast, 65mm lens plus ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. Southeast end room; view to northeast, 65mm lens plus electronic flash illumination. Failed south wall at right. - Benicia Arsenal, Powder Magazine No. 5, Junction of Interstate Highways 680 & 780, Benicia, Solano County, CA

  2. 17. Oblique view, typical room; view to south, 65mm lens ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Oblique view, typical room; view to south, 65mm lens plus electronic flash illumination. - Benicia Arsenal, Powder Magazine No. 5, Junction of Interstate Highways 680 & 780, Benicia, Solano County, CA

  3. 16. Oblique view, typical room; view to north, 65mm lens ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Oblique view, typical room; view to north, 65mm lens plus electronic flash illumination. - Benicia Arsenal, Powder Magazine No. 5, Junction of Interstate Highways 680 & 780, Benicia, Solano County, CA

  4. The pH of Mars

    NASA Technical Reports Server (NTRS)

    Plumb, R. C.; Bishop, J. L.; Edwards, J. O.

    1993-01-01

    The Viking labeled release (LR) experiments provided data that can be used to determine the acid-base characteristics of the regolith. Constraints on the acid-base properties and redox potentials of the Martian surface material would provide additional information for determining what reactions are possible and defining formation conditions for the regolith. Calculations devised to determine the pH of Mars must include the amount of soluble acid species or base species present in the LR regolith sample and the solubility product of the carbonate with the limiting solubility. This analysis shows that CaCO3, either as calcite or aragonite, has the correct K(sub sp) to have produced the Viking LR successive injection reabsorption effects. Thus CaCO3 or another MeCO3 with very similar solubility characteristics must have been present on Mars. A small amount of soluble acid, but no more than 4 micro-mol per sample, could also have been present. It is concluded that the pH of the regolith is 7.2 +/- 0.1.

  5. Histone Acetylation Regulates Intracellular pH

    PubMed Central

    McBrian, Matthew A.; Behbahan, Iman Saramipoor; Ferrari, Roberto; Su, Trent; Huang, Ta-Wei; Li, Kunwu; Hong, Candice S.; Christofk, Heather R.; Vogelauer, Maria; Seligson, David B.; Kurdistani, Siavash K.

    2014-01-01

    SUMMARY Differences in global levels of histone acetylation occur in normal and cancer cells, although the reason why cells regulate these levels has been unclear. Here we demonstrate a role for histone acetylation in regulating intracellular pH (pHi). As pHi decreases, histones are globally deacetylated by histone deacetylases (HDACs), and the released acetate anions are coexported with protons out of the cell by monocarboxylate transporters (MCTs), preventing further reductions in pHi. Conversely, global histone acetylation increases as pHi rises, such as when resting cells are induced to proliferate. Inhibition of HDACs or MCTs decreases acetate export and lowers pHi, particularly compromising pHi maintenance in acidic environments. Global deacetylation at low pH is reflected at a genomic level by decreased abundance and extensive redistribution of acetylation throughout the genome. Thus, acetylation of chromatin functions as a rheostat to regulate pHi with important implications for mechanism of action and therapeutic use of HDAC inhibitors. PMID:23201122

  6. Effect of pH and organic acids on nitrogen transformations and metal dissolution in soils

    SciTech Connect

    Fu, Minhong.

    1989-01-01

    The effect of pH (4, 6, and 8) on nitrogen mineralization was evaluated in three Iowa surface soils treated with crop residues (corn (Zea mays L.), soybean (Glycine max (L.) Merr.), and sorghum (Sorghum vulgare Pers.), or alfalfa (Medicago sativa L.)) and incubated in leaching columns under aerobic conditions at 30C for 20 weeks. In general, N mineralization was significantly depressed at soil pH 4, compared with pH 6 or 8. The types of crop residues added influenced the pattern and amount of N mineralization. A study on the effect of 19 trace elements on the nitrate red activity of four Iowa surface soils showed that most trace elements inhibited this enzyme in acid and neutral soils. The trace elements Ag(I), Cd(II), Se(IV), As(V), and W(VI) were the most effective inhibitors, with >75% inhibition. Mn(II) was the least effective inhibitor, with <10% inhibition. Other trace elements included Cu(I), Co(II), Cu(II), Fe(II), Ni(II), Pb(II), Zn(II), Al(III), As(III), Cr(III), Fe(III), V(IV), Mo(VI), and Se(VI). The application of high-performance liquid chromatography (HPLC) showed that, when coupled to a refractive index detector, it is a rapid, sensitive, and accurate method for determining organic acids in soils. Three organic acids, acetic (2-20 mM), propionic (0-3 mM), and n-butyric (0-1.4 mM), were identified with HPLC and confirmed by gas chromatography in crop-residue-treated soils incubated under waterlogged conditions at 25C for 72 h. No organic acids were detected under aerobic conditions. Four mineral acids and 29 organic acids were studied for their effect on N mineralization and metal dissolution in soils incubated under waterlogged conditions at 30C for 10 days.

  7. Intracellular pH regulation in isolated rat bile duct epithelial cells.

    PubMed Central

    Strazzabosco, M; Mennone, A; Boyer, J L

    1991-01-01

    To evaluate ion transport mechanisms in bile duct epithelium (BDE), BDE cells were isolated from bile duct-ligated rats. After short-term culture pHi was measured with a single cell microfluorimetric set-up using the fluorescent pHi indicator BCECF, and calibrated with nigericin in high K+ concentration buffer. Major contaminants were identified using vital markers. In HCO3(-)-free media, baseline pHi (7.03 +/- 0.12) decreased by 0.45 +/- 0.18 pH units after Na+ removal and by 0.12 +/- .04 after amiloride administration (1 mM). After acid loading (20 mM NH4Cl) pHi recovery was inhibited by both Na+ removal and amiloride (JH+ = 0.74 +/- 1.1, and JH+ = 2.28 +/- 0.8, respectively, vs. 5.47 +/- 1.97 and 5.97 +/- 1.76 mM/min, in controls, respectively). In HCO3- containing media baseline pHi was higher (7.16 +/- 0.1, n = 36, P less than 0.05) and was decreased by Na+ substitution but not by amiloride. Na+ removal inhibited pHi recovery after an intracellular acid load (0.27 +/- 0.26, vs. 7.7 +/- 4.1 mM/min, in controls), whereas amiloride reduced JH+ only by 27%. pH recovery was inhibited by DIDS (0.5-1 mM), but not by Cl- depletion. Finally, acute Cl- removal increased pHi by 0.18 pH units in the absence but not presence of DIDS. These data indicate that BDE cells possess mechanisms for Na+/H+ exchange, Na+:HCO3- symport and Cl-/HCO3 exchange. Therefore BDE may be capable of transepithelial H+/HCO3- transport. Images PMID:2022723

  8. Optical design and evaluation of a 4 mm cost-effective ultra-high-definition arthroscope

    PubMed Central

    Cheng, Dewen; Wang, Yongtian; Yu, Lu; Liu, Xiaohua

    2014-01-01

    High definition and magnification rigid endoscope plays an important role in modern minimally invasive medical surgery and diagnosis. In this paper, we present the design and evaluation methods of a high definition rigid endoscope, specifically an arthroscope, with a large depth of field (DOF). The incident heights and exit angles of the sampled rays on the relay lens are controlled during the optimization process to ensure an effective field view (70°) and a normal ray path within the limited lens diameter of 2.7 mm. The lens is set up as a multi-configuration system with two extreme and one middle object distances to cover a large DOF. As a result, an entrance pupil of 0.3 mm is achieved for the first time, to bring the theoretical resolution to 23.1 lps/mm in the object space at a working distance of 20 mm, with the wavelength of 0.532 um. The modulation transfer function (MTF) curves approach diffraction limit, and the values are all higher than 0.3 at 160 line pairs/mm (lps/mm) in the image space. Meanwhile, stray light caused by total internal reflection on the inner wall of the rod lenses and the objective lens is eliminated. The measured resolution in the object space at a 20 mm working distance is 22.3 lps/mm, and test results show that other performance characteristics also fulfill design requirements. The relay lenses are designed with only one type of the spacer and two types of lenses to greatly reduce the fabrication and assembly cost. The design method has important research and application values for lens systems used in modern minimally invasive medical surgery and industrial non-destructive testing area. PMID:25136495

  9. The MM2-cortical form of sporadic Creutzfeldt-Jakob disease presenting with visual disturbance.

    PubMed

    Nozaki, I; Hamaguchi, T; Noguchi-Shinohara, M; Ono, K; Shirasaki, H; Komai, K; Kitamoto, T; Yamada, M

    2006-08-01

    A subclass of sporadic Creutzfeldt-Jakob disease (sCJD) characterized by onset with visual symptoms (Heidenhain variant) has been reported to belong to the MM1 or MV1 type according to Parchi's classification. The authors report a 65-year-old woman with MM2-cortical sCJD with slowly progressive visual disturbance as the initial symptom. Diffusion-weighted MRIs revealed hyperintensity in both occipital cortices at an early stage. PMID:16894125

  10. Morphological evaluation of eccentric sets guide-plates of dcp-l 4.5 mm

    PubMed Central

    Borges, José Humberto de Souza; da Silva Filho, Antonio Lisboa; Pereira Neto, Francisco; Daher, Walter Rodrigo; de Mesquita, Alessandro Queiroz; Freitas, Anderson

    2012-01-01

    Objective To carry out isolated and comparative evaluations of the measurements of the set eccentric guide plates used in 4.5mm surgical implants, and to determine the effect of these measurements on compression strength. Methods Four eccentric guides, four large dynamic compression plates (L-DCP) from four local manufacturers, and a Vonder® 200 mm caliper brand were used. Five standard parameter measurements were created for the set eccentric guide-plate, which were identified as A to E. Four sets were made, using materials of the same factory, and identified as groups I to IV. The analyses were performed by measuring all the parameters from a ventral view of the plate, with the eccentric guide placed in the plate hole. Results Groups I and II showed the same values for all the parameters. All the groups showed the same measurements for E = 8.15 e B = 3.60. Group III: A = 8.10mm, C = 3.25mm, D = 1.25mm. Group IV: A = 7.00mm, C = 3.10mm, D = 0.30mm. Maximum compression force was (F Max.): Group I 80.58 N, Group. II: F Max. 81.63 N, Group. III: F Max. 36.32N, Group. IV: F Max. 37.52N Conclusion The measurements evaluated show a lack of standardization in the manufacture of orthopedic instruments and its effects on the values for compression strength. Level of Evidence: Level III, analytical study. PMID:24453573

  11. Performance of 300-mm lithography tools in a pilot production line

    NASA Astrophysics Data System (ADS)

    Maltabes, John G.; Charles, Alain B.; Hornig, Steffen R.; Schedel, Thorsten; Ganz, Dietmar; Schmidt, Sebastian

    1999-07-01

    Semiconductor 300 is the first pilot manufacturing facility for 300mm wafers in the world. This company is a joint venture between Siemens and Motorola, formed for the purpose of developing a 300mm manufacturing tool set. The pilot line contains a full compliment of tools for DRAM manufacturing. This paper discusses the performance of the initial 300mm lithography tool set installed in our pilot line in Dresden, Germany. The product used for evaluating and debugging the tool set is a 0.25-micron ground rule 64 Meg DRAM. This was chosen for the ability to easily benchmark against 200mm DRAM manufacturing data. We have produced several lots of wafers with measurable yield. These lots have produced data on overlay, CD and run to run performance of the lithography tools on actual product. We have data on resist coating, and develop uniformity. With several lithography tools installed we have generated a large amount of mix and match data. In addition several challenges for successful lithography have surfaced related entirely to the increase in wafer size. Film, etch, polish and thermal non-uniformity have impacted the throughput and performance of the lithography tools. The installation of the first integrated 300mm pilot line has also produced data on the impact larger wafer size has on tool logistics, for example fab layout, installation schedules and wafer and lot transport. While technical data is always important, the main reason for converting to 300mm is economic. We now have preliminary data on the comparison of 200 tools to 300mm tools in terms of footprint, throughput, and productivity gains for equivalent square centimeters of silicon. With this data we can start to make preliminary recommendations for 300mm manufacturing tools.

  12. A new smoothing function to introduce long-range electrostatic effects in QM/MM calculations

    NASA Astrophysics Data System (ADS)

    Fang, Dong; Duke, Robert E.; Cisneros, G. Andrés

    2015-07-01

    A new method to account for long range electrostatic contributions is proposed and implemented for quantum mechanics/molecular mechanics long range electrostatic correction (QM/MM-LREC) calculations. This method involves the use of the minimum image convention under periodic boundary conditions and a new smoothing function for energies and forces at the cutoff boundary for the Coulomb interactions. Compared to conventional QM/MM calculations without long-range electrostatic corrections, the new method effectively includes effects on the MM environment in the primary image from its replicas in the neighborhood. QM/MM-LREC offers three useful features including the avoidance of calculations in reciprocal space (k-space), with the concomitant avoidance of having to reproduce (analytically or approximately) the QM charge density in k-space, and the straightforward availability of analytical Hessians. The new method is tested and compared with results from smooth particle mesh Ewald (PME) for three systems including a box of neat water, a double proton transfer reaction, and the geometry optimization of the critical point structures for the rate limiting step of the DNA dealkylase AlkB. As with other smoothing or shifting functions, relatively large cutoffs are necessary to achieve comparable accuracy with PME. For the double-proton transfer reaction, the use of a 22 Å cutoff shows a close reaction energy profile and geometries of stationary structures with QM/MM-LREC compared to conventional QM/MM with no truncation. Geometry optimization of stationary structures for the hydrogen abstraction step by AlkB shows some differences between QM/MM-LREC and the conventional QM/MM. These differences underscore the necessity of the inclusion of the long-range electrostatic contribution.

  13. A new smoothing function to introduce long-range electrostatic effects in QM/MM calculations

    PubMed Central

    Fang, Dong; Duke, Robert E.; Cisneros, G. Andrés

    2015-01-01

    A new method to account for long range electrostatic contributions is proposed and implemented for quantum mechanics/molecular mechanics long range electrostatic correction (QM/MM-LREC) calculations. This method involves the use of the minimum image convention under periodic boundary conditions and a new smoothing function for energies and forces at the cutoff boundary for the Coulomb interactions. Compared to conventional QM/MM calculations without long-range electrostatic corrections, the new method effectively includes effects on the MM environment in the primary image from its replicas in the neighborhood. QM/MM-LREC offers three useful features including the avoidance of calculations in reciprocal space (k-space), with the concomitant avoidance of having to reproduce (analytically or approximately) the QM charge density in k-space, and the straightforward availability of analytical Hessians. The new method is tested and compared with results from smooth particle mesh Ewald (PME) for three systems including a box of neat water, a double proton transfer reaction, and the geometry optimization of the critical point structures for the rate limiting step of the DNA dealkylase AlkB. As with other smoothing or shifting functions, relatively large cutoffs are necessary to achieve comparable accuracy with PME. For the double-proton transfer reaction, the use of a 22 Å cutoff shows a close reaction energy profile and geometries of stationary structures with QM/MM-LREC compared to conventional QM/MM with no truncation. Geometry optimization of stationary structures for the hydrogen abstraction step by AlkB shows some differences between QM/MM-LREC and the conventional QM/MM. These differences underscore the necessity of the inclusion of the long-range electrostatic contribution. PMID:26233103

  14. A new smoothing function to introduce long-range electrostatic effects in QM/MM calculations

    SciTech Connect

    Fang, Dong; Duke, Robert E.; Andrés Cisneros, G.

    2015-07-28

    A new method to account for long range electrostatic contributions is proposed and implemented for quantum mechanics/molecular mechanics long range electrostatic correction (QM/MM-LREC) calculations. This method involves the use of the minimum image convention under periodic boundary conditions and a new smoothing function for energies and forces at the cutoff boundary for the Coulomb interactions. Compared to conventional QM/MM calculations without long-range electrostatic corrections, the new method effectively includes effects on the MM environment in the primary image from its replicas in the neighborhood. QM/MM-LREC offers three useful features including the avoidance of calculations in reciprocal space (k-space), with the concomitant avoidance of having to reproduce (analytically or approximately) the QM charge density in k-space, and the straightforward availability of analytical Hessians. The new method is tested and compared with results from smooth particle mesh Ewald (PME) for three systems including a box of neat water, a double proton transfer reaction, and the geometry optimization of the critical point structures for the rate limiting step of the DNA dealkylase AlkB. As with other smoothing or shifting functions, relatively large cutoffs are necessary to achieve comparable accuracy with PME. For the double-proton transfer reaction, the use of a 22 Å cutoff shows a close reaction energy profile and geometries of stationary structures with QM/MM-LREC compared to conventional QM/MM with no truncation. Geometry optimization of stationary structures for the hydrogen abstraction step by AlkB shows some differences between QM/MM-LREC and the conventional QM/MM. These differences underscore the necessity of the inclusion of the long-range electrostatic contribution.

  15. A single-size band, 50 mm long, for tricuspid annuloplasty.

    PubMed

    Calafiore, Antonio Maria; Iacò, Angela Lorena; Contini, Marco; Di Mauro, Michele

    2008-09-01

    A technique for tricuspid annuloplasty is presented, using a flexible 50mm long band, where the annular circumference is reduced to a fixed value of 78.5mm (circumference of #25 mm sizer). From June to February 2007, 15 consecutive patients with tricuspid regurgitation (TR) underwent tricuspid repair using this technique. The first suture is passed at the level of the anteroseptal commissure, the last one in the zone of the septal annulus, 28.5mm from the first one. The remaining sutures are passed as usual. All the sutures are then adapted to a 50mm long band. After a mean of 5.4 months from surgery, all patients are alive and asymptomatic. One patient showed residual 2/4 TR, due to enlarged RV with high pulmonary pressure despite a well functioning mitral prosthesis. Mean gradient across the tricuspid valve was 2.5+/-0.4 mmHg. This technique for tricuspid repair is simple and reliable, providing effective and reproducible results. PMID:18656374

  16. Sub-Nanometer Resolution Ultrasonic Motor for 300 mm Wafer Lithography Precision Stage

    NASA Astrophysics Data System (ADS)

    Egashira, Yoshiya; Kosaka, Kouji; Iwabuchi, Tetsuya; Kosaka, Tetsuya; Baba, Tetsuro; Endo, Taishi; Hashiguchi, Hiroyuki; Harada, Takashi; Nagamoto, Keiichi; Watanabe, Masayuki; Yamakawa, Takahiro; Miyata, Noboru; Moriyama, Shiro; Morizono, Yasuhiro; Nakada, Akira; Kubota, Hiroshi; Ohmi, Tadahiro

    2002-09-01

    This paper describes the development of the nonresonant ultrasonic motor (NRUSM) applied to a 300-mm-stroke ultra-precision stage for future LSI manufacturing, in particular electron beam based technologies. Advantages of the NRUSM are high resolution, no magnetic noise generation, high servo rigidity and high retention. It is confirmed that the NRUSM is suitable for ultra-precision positioning, and slow- and high-velocity feeding at closed-loop controls. The performance of the NRUSM-driven stage includes; (1) 85 mm/s feed velocity with average acceleration 375 mm/s2 over the 300 mm stroke at open-loop control; (2) ± 0.69 nm positioning accuracy at step and repeat response, 17 ms average positioning time for ± 30 nm positioning accuracy, positional error during constant velocity feeding below ± 1.5 nm for 100 nm/s and ± 40 nm for 20 mm/s, and velocity ripple at 36 mm/s is below 0.04% at closed-loop control.

  17. Quantum mechanical/molecular mechanical (QM/MM) docking: an evaluation for known test systems

    NASA Astrophysics Data System (ADS)

    Beierlein, Frank; Lanig, Harald; Schürer, Gudrun; Horn, Anselm H. C.; Clark, Timothy

    A combined quantum mechanical/molecular mechanical (QM/MM) docking approach for the investigation of protein-inhibitor complexes is presented. Starting points for QM/MM optimizations are generated with AutoDock. The subsequent semiempirical AM1 QM/MM optimization of the complex obtained by the docking procedure gives a more detailed description of the binding mode and the electronic properties of the ligand. As we use a flexible protein environment in the QM/MM optimizations, we are able to simulate limited structural changes of the enzyme upon binding a ligand, even within a simple geometry optimization. The method was validated using a set of structurally known protein-inhibitor complexes, whose crystallographic data were taken from the Protein Data Bank. In addition to protein structures taken directly from complexes with the inhibitors, structures of uncomplexed HIV-1-protease and thrombin were also used successfully for QM/MM docking experiments. By comparing the resulting structures with those obtained using protein structures from protein-inhibitor complexes, we find that the method is able to simulate the effect of the induced fit when a simple optimization is adequate to reproduce the protein movement. Describing the ligand quantum mechanically gives a detailed view of its electronic properties, for example its polarization within the active site of the enzyme. This study suggests strongly that a QM/MM molecular dynamics approach will be able to simulate the induced fit in general cases.

  18. Fabrication of vertex drift chamber with 1.75mm drift length

    NASA Astrophysics Data System (ADS)

    Sakuma, F.; En'yo, H.; Tabaru, T.; Yokkaichi, S.; Ishino, M.; Mihara, S.; Ozawa, K.; Hamagaki, H.; Funahashi, H.; Kitaguchi, M.; Miyashita, T.; Murakami, T.; Muto, R.; Naruki, M.; Sato, H. D.; Yamada, S.; Yoshimura, Y.; Kanda, H.; Chiba, J.; Ieiri, M.; Sasaki, O.; Sekimoto, M.; Tanaka, K. H.; Nomachi, M.

    2001-10-01

    The fabrication and the performance of the vertex drift chamber for the KEK-PS E325 are presented. The chamber consists of 3 layers of hexagonal drift cells with sides 3.02mm or 2.02mm long, depending on the region of polar angle coverage. The smallest drift length is only 1.75mm long. Such a geometry is realized with normal feed-through technics on the alminum frame by grounding cathodes and applying high voltages on anodes. The drift cells surround the targets at radii of 100 mm and 200 mm covering the polar angle region of 6 degrees to 141 degrees. The chamber is operated under 10^9/sec primary beam intensity, and the minimum distance between the beam and the sense wires is only 21mm. The chamber uses Amplifier-Shaper-Discriminator ICs (SONY CXA3183Q) for read-out, which are developed for Thin Gap Chamber for the ATLAS mun detector. In the presentation, we will report details of the chamber design and the measured performance.

  19. Day-to-night variations of cytoplasmic pH in a crassulacean acid metabolism plant.

    PubMed

    Hafke, J B; Neff, R; Hütt, M T; Lüttge, U; Thiel, G

    2001-01-01

    In crassulacean acid metabolism (CAM) large amounts of malic acid are redistributed between vacuole and cytoplasm in the course of night-to-day transitions. The corresponding changes of the cytoplasmic pH (pHcyt) were monitored in mesophyll protoplasts from the CAM plant Kalanchoe daigremontiana Hamet et Perrier by ratiometric fluorimetry with the fluorescent dye 2',7'-bis-(2-carboxyethyl)-5-(and-6-)carboxyfluorescein as a pHcyt indicator. At the beginning of the light phase, pHcyt was slightly alkaline (about 7.5). It dropped during midday by about 0.3 pH units before recovering again in the late-day-to-early-dark phase. In the physiological context the variation in pHcyt may be a component of CAM regulation. Due to its pH sensitivity, phosphoenolpyruvate carboxylase appears as a likely target enzyme. From monitoring delta pHcyt in response to loading the cytoplasm with the weak acid salt K-acetate a cytoplasmic H(+)-buffer capacity in the order of 65 mM H+ per pH unit was estimated at a pHcyt of about 7.5. With this value, an acid load of the cytoplasm by about 10 mM malic acid can be estimated as the cause of the observed drop in pHcyt. A diurnal oscillation in pHcyt and a quantitatively similar cytoplasmic malic acid is predicted from an established mathematical model which allows simulation of the CAM dynamics. The similarity of model predictions and experimental data supports the view put forward in this model that a phase transition of the tonoplast is an essential functional element in CAM dynamics. PMID:11732184

  20. Inactivation of adenovirus, reovirus and bacteriophages in fecal sludge by pH and ammonia.

    PubMed

    Magri, Maria Elisa; Fidjeland, Jørgen; Jönsson, Håkan; Albihn, Ann; Vinnerås, Björn

    2015-07-01

    The aim of this study was to evaluate the inactivation of adenovirus, reovirus and bacteriophages (MS2, ΦX174, 28B) in a fecal sludge. We conducted two experiments. In the first, we tested different compositions of the fecal sludge by mixing different amounts of water, feces and urine, totaling nine combinations which were kept at temperatures between 10 and 28°C. In the second study, urea was added to the mixtures, which were kept at temperatures from 5 to 33°C. The inactivation was based on a combination of temperature, pH and uncharged ammonia concentration. The increase in pH and ammonia was provided mainly by urine content (Experiment 1) and by urine and added urea (Experiment 2). The inactivation of bacteriophages was slower than the AdV and ReV. At 23°C and 28°, reasonable treatment times were obtained when pH was higher than 8.9 and NH3 concentrations were higher than 35 and 55 mM respectively. With those conditions, the maximum time for a 3 log reduction in viruses, according to this study, would be 35 days (23°C) and 21 days (28°C). However, in most applications where helminth eggs are present, the treatment time and NH3 for sanitization will be the scaling criteria, as they are more persistent. Concerning the sanitization of effluents from latrines, vacuum toilets or dry toilets in developing countries with tropical and sub-tropical climates, the use of intrinsic ammonia combined with high pH can be effective in producing a safe and highly valuable liquid that can be used as a fertilizer. In the case of the fecal sludge with very intrinsic ammonia concentration (<20 mM), sanitization could still be achieved by the addition of urea. PMID:25817758

  1. The Job Market for Ph.D.s: Two Views.

    ERIC Educational Resources Information Center

    Barkume, Megan

    1997-01-01

    Offers both optimistic and pessimistic views of the labor market for those with Doctor of Philosophy (Ph.D.) degrees. Discusses postdoctoral appointments and jobs for Ph.D.s outside the university. (JOW)

  2. Catalytic Decomposition of PH3 on Heated Tungsten Wire Surfaces

    NASA Astrophysics Data System (ADS)

    Umemoto, Hironobu; Nishihara, Yushin; Ishikawa, Takuma; Yamamoto, Shingo

    2012-08-01

    The catalytic decomposition processes of PH3 on heated tungsten surfaces were studied to clarify the mechanisms governing phosphorus doping into silicon substrates. Mass spectrometric measurements show that PH3 can be decomposed by more than 50% over 2000 K. H, P, PH, and PH2 radicals were identified by laser spectroscopic techniques. Absolute density measurements of these radical species, as well as their PH3 flow rate dependence, show that the major products on the catalyst surfaces are P and H atoms, while PH and PH2 are produced in secondary processes in the gas phase. In other words, catalytic decomposition, unlike plasma decomposition processes, can be a clean source of P atoms, which can be the only major dopant precursors. In the presence of an excess amount of H2, the apparent decomposition efficiency is small. This can be explained by rapid cyclic reactions including decomposition, deposition, and etching to reproduce PH3.

  3. Microscopic measurement of pH with iridium oxide microelectrodes

    PubMed

    Wipf; Ge; Spaine; Baur

    2000-10-15

    Microscopic pH electrodes were produced by deposition of hydrous iridium oxide onto carbon fiber microelectrodes. The electrodes exhibit two linear regions of potentiometric response between pH 2-6 and pH 6-12. The electrodes respond to pH changes within 50 ms, and an equilibrium value is reached within 30 s. By using these electrodes as probes in the scanning electrochemical microscope, dynamic pH changes occurring at or near a surface can be measured and pH maps of the surface can be generated. Vertical pH profiles and images of pH were obtained at substrates where electrochemical (oxidation and reduction of H2O2, hydrogen evolution) or enzymatic (glucose oxidase) reactions involving proton transfers occur. PMID:11055710

  4. Development of a porous polymer pH optrode.

    PubMed

    Liu, J N; Shahriari, M R; Sigel, G H

    1992-12-15

    A novel fiber-optic pH sensor has been developed with long-term stability and high sensitivity. The sensor is based on a porous cellulose triacetate fiber immobilized with Congo Red (pH indicator). This intrinsic fiberoptic pH sensor has shown excellent sensitivity, reversibility, and stability. It has also been demonstrated that the pH optrode is immune to metal-ion interferences. PMID:19798326

  5. INFLUENCE OF PH AND REDOX CONDITIONS ON COPPER LEACHING

    EPA Science Inventory

    Leaching behavior of metals from a mineral processing waste at varying pH and redox conditions was studies. Effect of combinations of pH and Eh on leaching of copper is described. Leaching of copper was found to be dependent on both pH and Eh. Higher concentrations of Cu were ...

  6. Acid Rain, pH & Acidity: A Common Misinterpretation.

    ERIC Educational Resources Information Center

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  7. pH of organ-culture-stored corneas.

    PubMed

    Lass, J H; Greiner, J V; Meneses, P; Morgan, D C; Medcalf, S K; Collie, D M; Skelnik, D L; Glonek, T

    1988-10-01

    Changes in intracorneal and storage-medium pH values of organ-culture-stored cat corneas were monitored over a 4-week period. The intracorneal pH was determined using the phosphorus-31 magnetic resonance spectroscopy (31P MRS) chemical shift of inorganic orthophosphate in conjunction with a standard pH titration curve. We incubated 32 adult cat corneas using two similar standard organ-culture methods, one with chondroitin sulfate (method 1) and the other without (method 2). Time-course data at 0, 1, 3 and 4 weeks of storage were used to calculate the rate of pH change. The intracorneal pH was not changed significantly for either organ-culture method; however, the storage-medium pH rate of change declined significantly for both methods (method 1, 0.15 pH units/week; method 2, 0.12 pH units/week). The difference between intracorneal and storage-medium pH values over time increased at a rate of 0.12 and 0.11 pH units/week for method 1 and method 2, respectively. The declining storage-medium pH in conjunction with the maintenance of intracorneal pH contributes to an increased metabolic demand on the cornea. PMID:3218477

  8. Ian Douglass Coulter, PhD

    PubMed Central

    Brown, Douglas M

    2004-01-01

    This paper focuses on Dr. Ian Coulter’s accomplishments from the time he became Executive Vice-President of CMCC in 1981, until he ended his presidency with a year’s administrative leave in 1990. Annual planning initiatives, pedagogy, scholarship, conflicts, and the quest for university affiliation are discussed as well as his legacy to the College and the chiropractic profession. The term “adventurous” was first attributed to Coulter by Oswald Hall, PhD, Professor Emeritus, University of Toronto who had worked closely with Coulter in a major investigation of the chiropractic profession from 1976 to 1979. Throughout this article the author tries to capture the spirit of daring, innovation and intellect that permeated Coulter’s presidency, enthralling his advocates and confounding his detractors. PMID:17549218

  9. Intracellular pH in Sperm Physiology

    PubMed Central

    Nishigaki, Takuya; José, Omar; González-Cota, Ana Laura; Romero, Francisco; Treviño, Claudia L.; Darszon, Alberto

    2014-01-01

    Intracellular pH (pHi) regulation is essential for cell function. Notably, several unique sperm ion transporters and enzymes whose elimination causes infertility are either pHi dependent or somehow related to pHi regulation. Amongst them are: CatSper, a Ca2+ channel; Slo3, a K+ channel; the sperm-specific Na+/H+ exchanger and the soluble adenylyl cyclase. It is thus clear that pHi regulation is of the utmost importance for sperm physiology. This review briefly summarizes the key components involved in pHi regulation, their characteristics and participation in fundamental sperm functions such as motility, maturation and the acrosome reaction. PMID:24887564

  10. Endoscopic mucosal resection of colorectal adenomas > 20 mm: Risk factors for recurrence

    PubMed Central

    Briedigkeit, Alexander; Sultanie, Omar; Sido, Bernd; Dumoulin, Franz Ludwig

    2016-01-01

    AIM: To evaluate risk factors for local recurrence after endoscopic mucosal resection of colorectal adenomas > 20 mm. METHODS: Retrospective data analysis of 216 endoscopic mucosal resections for colorectal adenomas > 20 mm in 179 patients (40.3% female; median age 68 years; range 35-91 years). All patients had at least 1 follow-up endoscopy with a minimum control interval of 2 mo (mean follow-up 6 mo/2.0-43.4 mo). Possible factors associated with local recurrence were analyzed by univariate and multivariate analysis. RESULTS: Median size of the lesions was 30 mm (20-70 mm), 69.0% were localized in the right-sided (cecum, ascending and transverse) colon. Most of the lesions (85.6%) showed a non-pedunculated morphology and the majority of resections was in piecemeal technique (78.7%). Histology showed carcinoma or high-grade intraepithelial neoplasia in 51/216 (23.6%) lesions including 4 low risk carcinomas (pT1a, L0, V0, R0 - G1/G2). Histologically proven recurrence was observed in 33/216 patients (15.3%). Patient age > 65 years, polyp size > 30 mm, non-pedunculated morphology, localization in the right-sided colon, piecemeal resection and tubular-villous histology were found as associated factors in univariate analysis. On multivariate analysis, only localization in the right-sided colon (HR = 6.842/95%CI: 1.540-30.394; P = 0.011), tubular-villous histology (HR = 3.713/95%CI: 1.617-8.528; P = 0.002) and polyp size > 30 mm (HR = 2.563/95%CI: 1.179-5.570; P = 0.017) were significantly associated risk factors for adenoma recurrence. CONCLUSION: Meticulous endoscopic follow-up is warranted after endoscopic mucosal resection of adenomas localized in the right-sided colon larger than > 30 mm, with tubular-villous histology. PMID:26981180

  11. Magnetomotive optical coherence elastography (MM-OCE) for thermal therapy dosimetry (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Huang, Pin-Chieh; Marjanovic, Marina; Spillman, Darold R.; Odintsov, Boris M.; Boppart, Stephen A.

    2016-03-01

    Biomechanical properties of tissues have been utilized for disease detection, diagnosis, and progression, however they have not been extensively utilized for therapy dosimetry. Magnetic hyperthermia aims to kill cells and ablate tumors using magnetic nanoparticles (MNPs) either injected in or targeted to tumors. Upon application of an appropriate AC magnetic field, MNPs can heat target tissue while sparing non-targeted healthy tissue. However, a sensitive monitoring technique for the dose of magnetic hyperthermia is needed to prevent over-treatment and collateral injury. During hyperthermia treatments, the viscoelastic properties of tissues are altered due to protein denaturation, coagulation, and tissue dehydration, making these properties candidates for dosimetry. Magnetomotive optical coherence elastography (MM-OCE) utilizes MNPs as internal force transducers to probe the biomechanical properties of tissues. Therefore, we aim to evaluate the hyperthermia dose based on the elastic changes revealed by MM-OCE. In this study, MNPs embedded in tissues were utilized for both hyperthermia and MM-OCE measurements. Tissue temperature and elastic modulus were obtained, where the elastic modulus was extracted from the resonance frequency detected by MM-OCE. Results showed a correlation between stiffness and temperature change following treatment. To investigate the thermal-dose-dependent changes, intervals of hyperthermia treatment were repeatedly performed on the same tissue sequentially, interspersed with MM-OCE. With increasing times of treatment, tissue stiffness increased, while temperature rise remained relatively constant. These results suggest that MM-OCE may potentially identify reversible and irreversible tissue changes during thermal therapy, supporting the use of MM-OCE for dosimetric control of hyperthermia in future applications.

  12. Metabolism and disposition of MM-433593, a selective FAAH-1 inhibitor, in monkeys

    PubMed Central

    Banijamali, Ali R; Wakefield, James D; Mermerian, Ara H; Busby, Robert W

    2014-01-01

    MM-433593 is a highly potent and selective inhibitor of fatty acid amide hydrolase-1 (FAAH-1) with potential utility as an orally administered treatment of pain, inflammation, and other disorders. In this study, we investigated the metabolism and pharmacokinetics of MM-433593 in monkeys, and compared plasma and urine metabolites of this compound to the in vitro metabolites produced by monkey hepatocytes. Intravenous administration of MM-433593 to cynomolgus monkeys produced a rapid distribution phase and slower elimination phase with a mean systemic clearance rate of 8–11 mL/min/kg. Absolute oral bioavailability was determined to be 14–21% with maximum plasma concentrations reached ∼3 h (Tmax) following a 10 mg/kg oral dose. The average terminal half-life of MM-433593 was 17–20 h, and there were no qualitative sex differences in the metabolite profile of MM-433593. The major site of metabolism was oxidation of the methyl group at the five position of the indole ring, which was confirmed by chromatography and mass spectrometry comparison to a synthesized authentic standard. This metabolite was further oxidized to the corresponding carboxylic acid and/or conjugated with sulfate, glucuronide, or glutathione. In all, 18 metabolites were found in plasma and urine. In vitro incubations of MM-433593 with monkey hepatocytes yielded 13 metabolites, all of which were found in vivo, indicating a good correlation between the in vitro and in vivo metabolism data. A comprehensive pathway for the metabolism of MM-433593 is proposed, including a plausible, five-step biotransformation for the formation of N-acetylcysteine conjugate metabolite (M18) from the hydroxylated parent (M5). PMID:25505606

  13. QM/MM simulation of liquid water with an adaptive quantum region.

    PubMed

    Bernstein, Noam; Várnai, Csilla; Solt, Iván; Winfield, Steven A; Payne, Mike C; Simon, István; Fuxreiter, Mónika; Csányi, Gábor

    2012-01-14

    The simulation of complex chemical systems often requires a multi-level description, in which a region of special interest is treated using a computationally expensive quantum mechanical (QM) model while its environment is described by a faster, simpler molecular mechanical (MM) model. Furthermore, studying dynamic effects in solvated systems or bio-molecules requires a variable definition of the two regions, so that atoms or molecules can be dynamically re-assigned between the QM and MM descriptions during the course of the simulation. Such reassignments pose a problem for traditional QM/MM schemes by exacerbating the errors that stem from switching the model at the boundary. Here we show that stable, long adaptive simulations can be carried out using density functional theory with the BLYP exchange-correlation functional for the QM model and a flexible TIP3P force field for the MM model without requiring adjustments of either. Using a primary benchmark system of pure water, we investigate the convergence of the liquid structure with the size of the QM region, and demonstrate that by using a sufficiently large QM region (with radius 6 Å) it is possible to obtain radial and angular distributions that, in the QM region, match the results of fully quantum mechanical calculations with periodic boundary conditions, and, after a smooth transition, also agree with fully MM calculations in the MM region. The key ingredient is the accurate evaluation of forces in the QM subsystem which we achieve by including an extended buffer region in the QM calculations. We also show that our buffered-force QM/MM scheme is transferable by simulating the solvated Cl(-) ion. PMID:22089416

  14. Effects of starvation on the transport of Escherichia coli K12 in saturated porous media are dependent on pH and ionic strength

    NASA Astrophysics Data System (ADS)

    Xu, S.; Walczak, J. J.; Wang, L.; Bardy, S. L.; Li, J.

    2010-12-01

    In this research, we investigate the effects of starvation on the transport of E. coli K12 in saturated porous media. Particularly, we examine the relationship between such effects and the pH and ionic strength of the electrolyte solutions that were used to suspend bacterial cells. E. coli K12 (ATCC 10798) cells were cultured using either Luria-Bertani Miller (LB-Miller) broth (10 g trypton, 5 g yeast extract and 10 g NaCl in 1 L of deionized water) or LB-Luria broth (10 g tryptone, 5 g yeast extract and 0.5 g NaCl in 1 L of deionized water). Both broths had similar pH (~7.1) but differed in ionic strength (LB-Miller: ~170 mM, LB-Luria: ~ 8 mM). The bacterial cells were then harvested and suspended using one of the following electrolyte solutions: phosphate buffered saline (PBS) (pH ~7.2; ionic strength ~170 mM), 168 mM NaCl (pH ~5.7), 5% of PBS (pH ~ 7.2; ionic strength ~ 8 mM) and 8 mM NaCl (pH ~ 5.7). Column transport experiments were performed at 0, 21 and 48 hours following cell harvesting to evaluate the change in cell mobility over time under “starvation” conditions. Our results showed that 1) starvation increased the mobility of E. coli K12 cells; 2) the most significant change in mobility occurred when bacterial cells were suspended in an electrolyte solution that had different pH and ionic strength (i.e., LB-Miller culture suspended in 8 mM NaCl and LB-Luria culture suspended in 168 mM Nacl); and 3) the change in cell mobility primarily occurred within the first 21 hours. The size of the bacterial cells was measured and the surface properties (e.g., zeta potential, hydrophobicity, cell-bound protein, LPS sugar content, outer membrane protein profiles) of the bacterial cells were characterized. We found that the measured cell surface properties could not fully explain the observed changes in cell mobility caused by starvation.

  15. Understanding Non-Traditional PhD Students Habitus--Implications for PhD Programmes

    ERIC Educational Resources Information Center

    Naidoo, Devika

    2015-01-01

    Against the background of vast changes in doctoral education and the emergence of non-traditional doctoral programmes, this paper investigates the habitus of non-traditional PhD students at a South African university. Bourdieu's conceptual tool of habitus informed the study. In-depth and open-ended interviews were conducted with 10 non-traditional…

  16. Comparison of Rumen Fluid pH by Continuous Telemetry System and Bench pH Meter in Sheep with Different Ranges of Ruminal pH

    PubMed Central

    Reis, Leonardo F.; Minervino, Antonio H. H.; Araújo, Carolina A. S. C.; Sousa, Rejane S.; Oliveira, Francisco L. C.; Rodrigues, Frederico A. M. L.; Meira-Júnior, Enoch B. S.; Barrêto-Júnior, Raimundo A.; Mori, Clara S.; Ortolani, Enrico L.

    2014-01-01

    We aimed to compare the measurements of sheep ruminal pH using a continuous telemetry system or a bench pH meter using sheep with different degrees of ruminal pH. Ruminal lactic acidosis was induced in nine adult crossbred Santa Ines sheep by the administration of 15 g of sucrose per kg/BW. Samples of rumen fluid were collected at the baseline, before the induction of acidosis (T0) and at six, 12, 18, 24, 48, and 72 hours after the induction for pH measurement using a bench pH meter. During this 72-hour period, all animals had electrodes for the continuous measurement of pH. The results were compared using the Bland-Altman analysis of agreement, Pearson coefficients of correlation and determination, and paired analysis of variance with Student's t-test. The measurement methods presented a strong correlation (r = 0.94, P < 0.05) but the rumen pH that was measured continuously using a telemetry system resulted in lower values than the bench pH meter (overall mean of 5.38 and 5.48, resp., P = 0.0001). The telemetry system was able to detect smaller changes in rumen fluid pH and was more accurate in diagnosing both subacute ruminal lactic acidosis and acute ruminal lactic acidosis in sheep. PMID:24967422

  17. PhD Students' Work Conditions and Study Environment in University- and Industry-Based PhD Programmes

    ERIC Educational Resources Information Center

    Kolmos, A.; Kofoed, L. B.; Du, X. Y.

    2008-01-01

    During the last 10 years, new models of funding and training PhD students have been established in Denmark in order to integrate industry into the entire PhD education. Several programmes have been conducted where it is possible to co-finance PhD scholarships or to become an employee as an industrial PhD in a company. An important question is what…

  18. Proton Transport and pH Control in Fungi.

    PubMed

    Kane, Patricia M

    2016-01-01

    Despite diverse and changing extracellular environments, fungi maintain a relatively constant cytosolic pH and numerous organelles of distinct lumenal pH. Key players in fungal pH control are V-ATPases and the P-type proton pump Pma1. These two proton pumps act in concert with a large array of other transporters and are highly regulated. The activities of Pma1 and the V-ATPase are coordinated under some conditions, suggesting that pH in the cytosol and organelles is not controlled independently. Genomic studies, particularly in the highly tractable S. cerevisiae, are beginning to provide a systems-level view of pH control, including transcriptional responses to acid or alkaline ambient pH and definition of the full set of regulators required to maintain pH homeostasis. Genetically encoded pH sensors have provided new insights into localized mechanisms of pH control, as well as highlighting the dynamic nature of pH responses to the extracellular environment. Recent studies indicate that cellular pH plays a genuine signaling role that connects nutrient availability and growth rate through a number of mechanisms. Many of the pH control mechanisms found in S. cerevisiae are shared with other fungi, with adaptations for their individual physiological contexts. Fungi deploy certain proton transport and pH control mechanisms not shared with other eukaryotes; these regulators of cellular pH are potential antifungal targets. This review describes current and emerging knowledge proton transport and pH control mechanisms in S. cerevisiae and briefly discusses how these mechanisms vary among fungi. PMID:26721270

  19. Analysis of stable tearing in a 7.6 mm thick aluminum plate alloy

    SciTech Connect

    Dawicke, D.S.; Piascik, R.S.; Newman, J.C. Jr.

    1997-12-31

    The behavior of a 7.6 mm thick 2000 series aluminum plate alloy was investigated. Fracture tests were conducted on 304.8 mm and 101.6 mm wide M(T) specimens and 152.4 mm and 101.6 C(T) specimens. Two-dimensional and three-dimensional, elastic-plastic finite element simulations used the critical CTOA criterion to simulate the fracture behavior. A plane strain core was used in the two-dimensional analyses to approximate the three-dimensional constraint. The results from this study indicate: (A) The three-dimensional finite element analyses required a critical CTOA of 5.75{degree} to simulate the fracture behavior of the 101.6 mm and 304.8 mm wide M(T) specimen with side grooves. This angle was about the upper limit of the surface CTOA measurements. (B) The three-dimensional finite element analyses required a critical CTOA of 3.6{degree} to simulate the fracture behavior of the 101.6 mm C(T) specimen with side grooves. This angle was about the upper limit of the microtopography through-thickness CTOA measurements. (C) A plane strain core height of PSC = 4 mm was required for the two-dimensional analyses to match the fracture behavior obtained from the three-dimensional analyses. This height agreed with the distance that a three-dimensional analysis indicated was the start of plane strain like behavior. (D) For large M(T) specimens (W > 1,000 mm) the two-dimensional plane strain core analysis predicted a failure stress between the plane stress and plane strain conditions and provided a good approximation of the three-dimensional analyses. (E) The experimental measurements and analytical results show good agreement when the specimens sizes meet the uncracked ligament to thickness ratio (b/B > 4) determined by Newman et al. This indicates that there is a minimum size laboratory specimen that can be used to determine the material behavior needed to predict fracture in large specimens and structures.

  20. Development and application of QM/MM methods to study the solvation effects and surfaces

    SciTech Connect

    Dibya, Pooja Arora

    2010-01-01

    Quantum mechanical (QM) calculations have the advantage of attaining high-level accuracy, however QM calculations become computationally inefficient as the size of the system grows. Solving complex molecular problems on large systems and ensembles by using quantum mechanics still poses a challenge in terms of the computational cost. Methods that are based on classical mechanics are an inexpensive alternative, but they lack accuracy. A good trade off between accuracy and efficiency is achieved by combining QM methods with molecular mechanics (MM) methods to use the robustness of the QM methods in terms of accuracy and the MM methods to minimize the computational cost. Two types of QM combined with MM (QM/MM) methods are the main focus of the present dissertation: the application and development of QM/MM methods for solvation studies and reactions on the Si(100) surface. The solvation studies were performed using a discreet solvation model that is largely based on first principles called the effective fragment potential method (EFP). The main idea of combining the EFP method with quantum mechanics is to accurately treat the solute-solvent and solvent-solvent interactions, such as electrostatic, polarization, dispersion and charge transfer, that are important in correctly calculating solvent effects on systems of interest. A second QM/MM method called SIMOMM (surface integrated molecular orbital molecular mechanics) is a hybrid QM/MM embedded cluster model that mimics the real surface.3 This method was employed to calculate the potential energy surfaces for reactions of atomic O on the Si(100) surface. The hybrid QM/MM method is a computationally inexpensive approach for studying reactions on larger surfaces in a reasonably accurate and efficient manner. This thesis is comprised of four chapters: Chapter 1 describes the general overview and motivation of the dissertation and gives a broad background of the computational methods that have been employed in this work

  1. Use of 5-mm-diameter implants: Periotest values related to a clinical and radiographic evaluation.

    PubMed

    Aparicio, C; Orozco, P

    1998-12-01

    A modified design of the original Brånemark implant consisting of a cp. Titanium 5.0-mm-diameter self-tapping implant threaded up to the marginal platform has been proposed for specific indications. From February 1992 to November 1995, a total of 185 machined screw implants (Nobel Biocare, Gothenburg, Sweden) were installed in 45 patients to withstand 58 prostheses. Of these, 91 were 3.75-mm diameter and 94 were 5.0-mm wide. Most of the implants were placed in type B and C bone quantity and type 2 and 3 bone quality. A retrospective evaluation with regard to indications, marginal bone remodelling, Periotest values (PTv) and survival rate is presented. PTv and radiographic measurements were made at abutment connection and repeated 3, 6 and 12 months later and thereafter every year. The follow-up ranged from 16 to 55 months (mean 32.9 months) post-loading. Three patients with 8 5.0-mm implants dropped-out of the study at different stages. Out of the wide implants, 1 was expelled during the healing period; 3 were found mobile at the abutment connection; 1 lost its osseointegration suddenly after 2 years of function; 4 belonging to 1 patient did not meet the success criteria due to continuous marginal bone loss. The cumulative success rate of 5.0-mm implants (CSR) after 1 year of function was 97.2% for upper jaws and 88.4% in mandibles, whereas the CSR in maxilla after 48 months was 97.2% and 83.4% in mandibles. The obtained PTv from 5.0-mm-wide fixtures in maxilla and mandibles were respectively 1.1 and 0.6 units lower than those obtained PTv for 3.75-mm-diameter implants in the same patients. The hypothesis that there are differences in the damping capacity of the bone surrounding a 5.0-mm-wide implant compared to the 3.75-mm-diameter implant is supported by the PTv results. PMID:11429941

  2. POLYVIEW-MM: web-based platform for animation and analysis of molecular simulations

    PubMed Central

    Porollo, Aleksey; Meller, Jaroslaw

    2010-01-01

    Molecular simulations offer important mechanistic and functional clues in studies of proteins and other macromolecules. However, interpreting the results of such simulations increasingly requires tools that can combine information from multiple structural databases and other web resources, and provide highly integrated and versatile analysis tools. Here, we present a new web server that integrates high-quality animation of molecular motion (MM) with structural and functional analysis of macromolecules. The new tool, dubbed POLYVIEW-MM, enables animation of trajectories generated by molecular dynamics and related simulation techniques, as well as visualization of alternative conformers, e.g. obtained as a result of protein structure prediction methods or small molecule docking. To facilitate structural analysis, POLYVIEW-MM combines interactive view and analysis of conformational changes using Jmol and its tailored extensions, publication quality animation using PyMol, and customizable 2D summary plots that provide an overview of MM, e.g. in terms of changes in secondary structure states and relative solvent accessibility of individual residues in proteins. Furthermore, POLYVIEW-MM integrates visualization with various structural annotations, including automated mapping of known inter-action sites from structural homologs, mapping of cavities and ligand binding sites, transmembrane regions and protein domains. URL: http://polyview.cchmc.org/conform.html. PMID:20504857

  3. Fourier transform infrared absorption spectroscopy characterization of gaseous atmospheric pressure plasmas with 2 mm spatial resolution

    SciTech Connect

    Laroche, G.; Vallade, J.; Bazinette, R.; Hernandez, E.; Hernandez, G.; Massines, F.; Nijnatten, P. van

    2012-10-15

    This paper describes an optical setup built to record Fourier transform infrared (FTIR) absorption spectra in an atmospheric pressure plasma with a spatial resolution of 2 mm. The overall system consisted of three basic parts: (1) optical components located within the FTIR sample compartment, making it possible to define the size of the infrared beam (2 mm Multiplication-Sign 2 mm over a path length of 50 mm) imaged at the site of the plasma by (2) an optical interface positioned between the spectrometer and the plasma reactor. Once through the plasma region, (3) a retro-reflector module, located behind the plasma reactor, redirected the infrared beam coincident to the incident path up to a 45 Degree-Sign beamsplitter to reflect the beam toward a narrow-band mercury-cadmium-telluride detector. The antireflective plasma-coating experiments performed with ammonia and silane demonstrated that it was possible to quantify 42 and 2 ppm of these species in argon, respectively. In the case of ammonia, this was approximately three times less than this gas concentration typically used in plasma coating experiments while the silane limit of quantification was 35 times lower. Moreover, 70% of the incoming infrared radiation was focused within a 2 mm width at the site of the plasma, in reasonable agreement with the expected spatial resolution. The possibility of reaching this spatial resolution thus enabled us to measure the gaseous precursor consumption as a function of their residence time in the plasma.

  4. Ultra-Compact Multitip Scanning Probe Microscope with an Outer Diameter of 50 mm

    NASA Astrophysics Data System (ADS)

    Cherepanov, Vasily; Zubkov, Evgeny; Junker, Hubertus; Korte, Stefan; Blab, Marcus; Coenen, Peter; Voigtländer, Bert

    We present a multitip scanning tunneling microscope (STM) where four independent STM units are integrated on a diameter of 50 mm. The coarse positioning of the tips is done under the control of an optical microscope or an SEM in vacuum. The heart of this STM is a new type of piezoelectric coarse approach called Koala Drive which can have a diameter greater than 2.5 mm and a length smaller than 10 mm. Alternating movements of springs move a central tube which holds the STM tip or AFM sensor. This new operating principle provides a smooth travel sequence and avoids shaking which is intrinsically present for nanopositioners based on inertial motion with saw tooth driving signals. Inserting the Koala Drive in a piezo tube for xyz-scanning integrates a complete STM inside a 4 mm outer diameter piezo tube of <10 mm length. The use of the Koala Drive makes the scanning probe microscopy design ultra-compact and accordingly leads to a high mechanical stability. The drive is UHV, low temperature, and magnetic field compatible. The compactness of the Koala Drive allows building a four-tip STM as small as a single-tip STM with a drift of <0.2 nm/min and lowest resonance frequencies of 2.5 (xy) and 5.5 kHz (z). We present examples of the performance of the multitip STM designed using the Koala Drive.

  5. Quantifying and monitoring convection intensity from mm-wave sounder observations

    NASA Astrophysics Data System (ADS)

    Haddad, Ziad S.; Sawaya, Randy S.; Kacimi, Sahra; Sy, Ousmane O.; Steward, Jeffrey L.

    2016-05-01

    Few systematic attempts to interpret the measurements of mm-wave radiometers over clouds and precipitation have been made to date because the scattering signatures of hydrometeors at these frequencies are very difficult to model. The few algorithms that have been developed try to retrieve surface precipitation, to which the observations are partially correlated but not directly sensitive. In fact, over deep clouds, mm-wave radiometers are most sensitive to the scattering from solid hydrometeors within the upper levels of the cloud. In addition, mm-wave radiometers have a definite advantage over the lower-frequency window-channel radiometers in that they have finer resolution and can therefore explicitly resolve deep convection. Preliminary analyses (in particular of NOAA's MHS brightness temperatures, as well as Megha-Tropiques's SAPHIR observations) indicate that the measurements are indeed very sensitive to the depth and intensity of convection. The challenge is to derive a robust approach to make quantitative estimates of the convection, for example the height and depth of the condensed water, directly from the mm-wave observations, as a function of horizontal location. To avoid having to rely on a specific set of microphysical assumptions, this analysis exploits the substantial amount of nearly- simultaneous coincident observations by mm-wave radiometers and orbiting atmospheric profiling radars in order to enforce unbiased consistency between the calculated brightness temperatures and the radar and radiometer observations.

  6. Simulation of Adsorption Processes at Metallic Interfaces: An Image Charge Augmented QM/MM Approach.

    PubMed

    Golze, Dorothea; Iannuzzi, Marcella; Nguyen, Manh-Thuong; Passerone, Daniele; Hutter, Jürg

    2013-11-12

    A novel method for including polarization effects within hybrid quantum mechanics/molecular mechanics (QM/MM) simulations of adsorbate-metal systems is presented. The interactions between adsorbate (QM) and metallic substrate (MM) are described at the MM level of theory. Induction effects are additionally accounted for by applying the image charge formulation. The charge distribution induced within the metallic substrate is modeled by a set of Gaussian charges (image charges) centered at the metal atoms. The image charges and the electrostatic response of the QM potential are determined self-consistently by imposing the constant-potential condition within the metal. The implementation is embedded in a highly efficient Gaussian and plane wave framework and is naturally suited for periodic systems. Even though the electronic properties of the metallic substrate are not taken into account explicitly, the augmented QM/MM scheme can reproduce characteristic polarization effects of the adsorbate. The method is assessed through the investigation of structural and electronic properties of benzene, nitrobenzene, thymine, and guanine on Au(111). The study of small water clusters adsorbed on Pt(111) is also reported in order to demonstrate that the approach provides a sizable correction of the MM-based interactions between adsorbate and substrate. Large-scale molecular dynamics (MD) simulations of a water film in contact with a Pt(111) surface show that the method is suitable for simulations of liquid/metal interfaces at reduced computational cost. PMID:26583423

  7. Survival and growth of age-0 steelhead after surgical implantation of 23-mm passive integrated transponders

    USGS Publications Warehouse

    Bateman, D.S.; Gresswell, R.E.

    2006-01-01

    Little information is available on the effects of implanting 23-mm passive integrated transponder (PIT) tags in salmonids less than 90 mm fork length (FL). Using juvenile steelhead Oncorhynchus mykiss (range, 73–97 mm FL), we compared instantaneous growth rates and survival among three experimental groups: control, surgery with no tag, and surgery with tag. Survival rate was lower for tagged fish (86%) than for control and surgery−no tag fish (virtually 100% in each group). Approximately 90% of the mortalities occurred during days 1–3. Growth rate for the tagged group was lower for the first two 10-d measurement intervals; however, during the third 10-d interval, growth rates for tagged fish equaled or exceeded values for the other groups. These results suggest that tagged fish recovered by day 20. Growth rates for the control and surgery−no tag groups did not differ from one another during any measurement interval. Tag retention rate was 97% over the 30-d period of the study. It appears that the combination of fish length and tag size in this study resulted in short-term negative effects on growth rate and survival; however, 23-mm PIT tags may still be useful for studies of salmonids 80–90 mm FL when survival is not the parameter of interest.

  8. Intracellular pH of acid-tolerant ruminal bacteria.

    PubMed Central

    Russell, J B

    1991-01-01

    Acid-tolerant ruminal bacteria (Bacteroides ruminicola B1(4), Selenomonas ruminantium HD4, Streptococcus bovis JB1, Megasphaera elsdenii B159, and strain F) allowed their intracellular pH to decline as a function of extracellular pH and did not generate a large pH gradient across the cell membrane until the extracellular pH was low (less than 5.2). This decline in intracellular pH prevented an accumulation of volatile fatty acid anions inside the cells. PMID:1781695

  9. The Role of pH Regulation in Cancer Progression.

    PubMed

    McIntyre, Alan; Harris, Adrian L

    2016-01-01

    Frequently observed phenotypes of tumours include high metabolic activity, hypoxia and poor perfusion; these act to produce an acidic microenvironment. Cellular function depends on pH homoeostasis, and thus, tumours become dependent on pH regulatory mechanisms. Many of the proteins involved in pH regulation are highly expressed in tumours, and their expression is often of prognostic significance. The more acidic tumour microenvironment also has important implications with regard to chemotherapeutic and radiotherapeutic interventions. In addition, we review pH-sensing mechanisms, the role of pH regulation in tumour phenotype and the use of pH regulatory mechanisms as therapeutic targets. PMID:27557536

  10. Time course of pH change in plant epidermis using microscopic pH imaging system

    NASA Astrophysics Data System (ADS)

    Dan, Risako; Shimizu, Megumi; Kazama, Haruko; Sakaue, Hirotaka

    2010-11-01

    We established a microscopic pH imaging system to track the time course of pH change in plant epidermis in vivo. In the previous research, we have found out that anthocyanin containing cells have higher pH. However, it was not clear whether the anthocyanin increased the pH or anthocyanin was synthesized result from the higher pH. Therefore, we further investigated the relationship between anthocyanin and pH change. To track the time course of pH change in plant epidermis, we established a system using luminescent imaging technique. We used HPTS (8-Hydroxypyrene-1,3,6-Trisulfonate) as pH indicator and applied excitation ratio imaging method. Luminescent image was converted to a pH distribution by obtained in vitro calibration using known pH solution. Cellular level observation was enabled by merging microscopic color picture of the same region to the pH change image. The established system was applied to epidermal cells of red-tip leaf lettuce, Lactuca Sativa L. and the time course was tracked in the growth process. We would discuss about the relationship between anthocyanin and pH change in plant epidermis.

  11. The Effect of Crystallizing and Non-crystallizing Cosolutes on Succinate Buffer Crystallization and the Consequent pH Shift in Frozen Solutions

    SciTech Connect

    Sundaramurthi, Prakash; Suryanarayanan, Raj

    2011-09-06

    To effectively inhibit succinate buffer crystallization and the consequent pH changes in frozen solutions. Using differential scanning calorimetry (DSC) and X-ray diffractometry (XRD), the crystallization behavior of succinate buffer in the presence of either (i) a crystallizing (glycine, mannitol, trehalose) or (ii) a non-crystallizing cosolute (sucrose) was evaluated. Aqueous succinate buffer solutions, 50 or 200 mM, at pH values 4.0 or 6.0 were cooled from room temperature to -25 C at 0.5 C/min. The pH of the solution was measured as a function of temperature using a probe designed to function at low temperatures. The final lyophiles prepared from these solutions were characterized using synchrotron radiation. When the succinic acid solution buffered to pH 4.0, in the absence of a cosolute, was cooled, there was a pronounced shift in the freeze-concentrate pH. Glycine and mannitol, which have a tendency to crystallize in frozen solutions, remained amorphous when the initial pH was 6.0. Under this condition, they also inhibited buffer crystallization and prevented pH change. At pH 4.0 (50 mM initial concentration), glycine and mannitol crystallized and did not prevent pH change in frozen solutions. While sucrose, a non-crystallizing cosolute, did not completely prevent buffer crystallization, the extent of crystallization was reduced. Sucrose decomposition, based on XRD peaks attributable to {beta}-D-glucose, was observed in frozen buffer solutions with an initial pH of 4.0. Trehalose completely inhibited crystallization of the buffer components when the initial pH was 6.0 but not at pH 4.0. At the lower pH, the crystallization of both trehalose dihydrate and buffer components was evident. When retained amorphous, sucrose and trehalose effectively inhibited succinate buffer component crystallization and the consequent pH shift. However, when trehalose crystallized or sucrose degraded to yield a crystalline decomposition product, crystallization of buffer was

  12. VizieR Online Data Catalog: Mono-13C acetaldehydes mm/submm wave spectra (Margules+,

    NASA Astrophysics Data System (ADS)

    Margules, L.; Motiyenko, R. A.; Ilyushin, V. V.; Guillemin, J.-C.

    2015-06-01

    This paper is a continuation of a series of studies conducted in PhLAM Lille (France) that are devoted to the investigations of the spectra of different isotopic species of astrophysical molecules. We present a new study of the 13CH3CHO and CH313CHO spectra with measurements and analysis extended up to 945GHz. (6 data files).

  13. Instrument development and field application of the in situ pH Calibrator at the Ocean Observatory

    NASA Astrophysics Data System (ADS)

    Tan, C.; Ding, K.; Seyfried, W. E.

    2012-12-01

    A novel, self-calibrating instrument for in-situ measurement of pH in deep sea environments up to 4000 m has recently been developed. The device utilizes a compact fluid delivery system to perform measurement and two-point calibration of the solid state pH sensor array (Ir|IrOx| Ag|AgCl), which is sealed in a flow cell to enhance response time. The fluid delivery system is composed of a metering pump and valves, which periodically deliver seawater samples into the flow cell to perform measurements. Similarly, pH buffer solutions can be delivered into the flow cell to calibrate the electrodes under operational conditions. Sensor signals are acquired and processed by a high resolution (0.25 mV) datalogger circuit with a size of 114 mm×31 mm×25 mm. Eight input channels are available: two high impedance sensor input channels, two low impedance sensor input channel, two thermocouple input channels and two thermistor input channels. These eight channels provide adequate measurement flexibility to enhance applications in deep sea environments. The two high impedance channels of the datalogger are especially designed with the input impedance of 1016 Ω for YSZ (yittria-stabilized zirconia) ceramic electrodes characterized by the extremely low input bias current and high resistance. Field tests have been performed in 2008 by ROV at the depth up to 3200 m. Using the continuous power supply and TCP/IP network capability of the Monterey Accelerated Research System (MARS) ocean observatory, the so-called "pH Calibrator" has the capability of long term operation up to six months. In the observatory mode, the electronics are configured with DC-DC power converter modules and Ethernet to serial module to gain access to the science port of seafloor junction box. The pH Calibrator will be deployed at the ocean observatory in October and the in situ data will be on line on the internet. The pH Calibrator presents real time pH data at high pressures and variable temperatures, while

  14. Seawater pH sensor based on the long period grating in a single-mode-multimode-single-mode structure

    NASA Astrophysics Data System (ADS)

    Wang, Ke; Klimov, Denis; Kolber, Zbigniew

    2009-03-01

    A pH sensor is developed based on the long-period grating (LPG) inscribed into a single-mode-multimode-single-mode (SMS) structure in order to measure the pH in seawater. The LPG is formed by using a focused CO2 laser at LPG's critical period (1 mm). The transmission characteristics are similar to that of a multimode fiber. However, the SMS structure has a higher sensitivity because mode coupling only happens between the fundamental mode and higher-order modes in the SMS structure. The pH-sensitive hydrogel is made by the thermal cross-link of poly vinyl alcohol and poly acrylic acid. This sensor has been utilized in seawater pH sensing in the range of 6-8. Experiments have confirmed that the sensor is sensitive and repeatable.

  15. A possible effector role for the pleckstrin homology (PH) domain of dynamin

    PubMed Central

    Bethoney, Kelley A.; King, Megan C.; Hinshaw, Jenny E.; Ostap, E. Michael; Lemmon, Mark A.

    2009-01-01

    The large GTPase dynamin plays a key role in clathrin-mediated endocytosis in animal cells, although its mechanism of action remains unclear. Dynamins 1, 2, and 3 contain a pleckstrin homology (PH) domain that binds phosphoinositides with a very low affinity (KD > 1 mM), and this interaction appears to be crucial for function. These observations prompted the suggestion that an array of PH domains drives multivalent binding of dynamin oligomers to phosphoinositide-containing membranes. Although in vitro experiments reported here are consistent with this hypothesis, we find that PH domain mutations that abolish dynamin function do not alter localization of the protein in transfected cells, indicating that the PH domain does not play a simple targeting role. An alternative possibility is suggested by the geometry of dynamin helices resolved by electron microscopy. Even with one phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2] molecule bound per PH domain, these dynamin assemblies will elevate the concentration of PtdIns(4,5)P2 at coated pit necks, and effectively cluster (or sequester) this phosphoinositide. In vitro fluorescence quenching studies using labeled phosphoinositides are consistent with dynamin-induced PtdIns(4,5)P2 clustering. We therefore propose that the ability of dynamin to alter the local distribution of PtdIns(4,5)P2 could be crucial for the role of this GTPase in promoting membrane scission during clathrin-mediated endocytosis. PtdIns(4,5)P2 clustering could promote vesicle scission through direct effects on membrane properties, or might play a role in dynamin's ability to regulate actin polymerization. PMID:19666604

  16. Effects of pH and bicarbonate on mitochondrial functions of marine bivalves.

    PubMed

    Haider, Fouzia; Falfushynska, Halina; Ivanina, Anna V; Sokolova, Inna M

    2016-08-01

    Estuarine organisms including mollusks are exposed to periodic oxygen deficiency (hypoxia) that leads to a decrease in intracellular pH and accumulation of bicarbonate (HCO3(-)). These changes can affect cellular bioenergetics; however, their effects on mitochondria of estuarine mollusks are not well understood. We determined the interactive effects of bicarbonate (0-10mM) and pH (7.2 and 6.5) on mitochondrial oxygen consumption (ṀO2), membrane potential (Δψ) and production of reactive oxygen species (ROS) in two common estuarine bivalves - hard clams Mercenaria mercenaria, and bay scallops Argopecten irradians. In both species, elevated HCO3(-) levels suppressed ADP-stimulated (state 3) ṀO2 but had little effect on the resting (state 4) respiration. These effects were not mediated by the soluble adenylyl cyclase or cyclic AMP. Effects of the low pH (6.5) on mitochondrial traits were species-specific and depended on the substrate oxidized by the mitochondria. Mild acidosis (pH6.5) had minimal effects on ṀO2 and Δψ of the bivalve mitochondria oxidizing pyruvate but led to increased rates of ROS production in clams (ROS production could not be measured in scallops). In succinate-respiring mitochondria of clams, mild acidosis suppressed ṀO2 and increased mitochondrial coupling, while in scallop mitochondria the effects of low pH were opposite. Suppression of mitochondrial oxidative phosphorylation by bicarbonate and/or acidosis may contribute to the metabolic rate depression during shell closure or environmental hypoxia/hypercapnia. These findings have implications for understanding the physiological mechanisms involved in regulation of mitochondrial bioenergetics during hypoxia exposure in estuarine bivalves. PMID:27044911

  17. Dehydration of Methanediol in Aqueous Solution: An ONIOM(QM/MM) Study.

    PubMed

    Inaba, Satoshi; Sameera, W M C

    2016-08-25

    We used ONIOM(QM/MM) method to examine the dehydration of a methanediol in aqueous solution. A methanediol and a small number of water molecules in the proximity of the methanediol are calculated with quantum mechanics (QM), while a number of water molecules far from the methanediol are calculated with molecular mechanics (MM). A molecular dynamical simulation shows that 12 water molecules are located within the hydration shell of a methanediol. The energy barrier for the dehydration of a methanediol decreases when we increase the number of water molecules in the QM region and converges toward a finite value when 12 water molecules are included in the QM region. This indicates a significant effect of water molecules within the hydration shell on the dehydration process of a methanediol in aqueous solution. The dehydration rate calculated with the ONIOM(QM/MM) method agrees well with that obtained from a laboratory experiment. PMID:27490867

  18. 450mm etch process development and process chamber evaluation using 193i DSA guided pattern

    NASA Astrophysics Data System (ADS)

    Collison, Wenli; Lin, Yii-Cheng; Dunn, Shannon; Takikawa, Hiroaki; Paris, James; Chen, Lucy; Detrick, Troy; Belen, Jun; Stojakovic, George; Goss, Michael; Fish, Norman; Park, Minjoon; Sun, Chih-Ming; Kelling, Mark; Lin, Pinyen

    2016-03-01

    In the Global 450mm Equipment Development Consortium (G450C), a 193i guided directed self-assembly (DSA) pattern has been used to create structures at the 14nm node and below. The first guided DSA patterned wafer was ready for etch process development within a month of the G450C's first 193i patterned wafer availability with one litho pass. Etch processes were scaled up from 300mm to 450mm for a 28nm pitch STI stack and a 40nm pitch M1 BEOL stack. The effects of various process parameters were investigated to fine tune each process. Overall process window has been checked and compared. Excellent process stability results were shown for current etch chambers.

  19. Smart-Cut ® technology: from 300 mm ultrathin SOI production to advanced engineered substrates

    NASA Astrophysics Data System (ADS)

    Maleville, Christophe; Mazuré, Carlos

    2004-06-01

    The Smart-Cut ® process, based on hydrogen implantation and wafer bonding, is a generic thin layer process transfer. Unibond ® SOI wafers are today in volume production, showing that splitting and bonding steps can be controlled, with high yields. Taking advantage of standard equipments flexibility, the process has been successfully scaled up to 300 mm. Most advanced 200 mm processes were successfully transferred to 300 mm, with wafers showing uniformity and defectivity results compatible with industry requirements for fully depleted device applications. The number of wafer solutions offered by the Smart-Cut ® technology is already much greater than just SOI. Strained silicon on insulator, silicon on quartz (SOQ), single crystal silicon layer on plastic supports, silicon carbide on insulator, germanium on insulator, multilayer SOI structures are just few examples of the potential of Smart Cut ® to engineer and design new substrates to answer the demands of the industry. A review of the progress achieved is given.

  20. LICHEM: A QM/MM program for simulations with multipolar and polarizable force fields.

    PubMed

    Kratz, Eric G; Walker, Alice R; Lagardère, Louis; Lipparini, Filippo; Piquemal, Jean-Philip; Andrés Cisneros, G

    2016-04-30

    We introduce an initial implementation of the LICHEM software package. LICHEM can interface with Gaussian, PSI4, NWChem, TINKER, and TINKER-HP to enable QM/MM calculations using multipolar/polarizable force fields. LICHEM extracts forces and energies from unmodified QM and MM software packages to perform geometry optimizations, single-point energy calculations, or Monte Carlo simulations. When the QM and MM regions are connected by covalent bonds, the pseudo-bond approach is employed to smoothly transition between the QM region and the polarizable force field. A series of water clusters and small peptides have been employed to test our initial implementation. The results obtained from these test systems show the capabilities of the new software and highlight the importance of including explicit polarization. © 2016 Wiley Periodicals, Inc. PMID:26781073