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Sample records for mm borax ph

  1. Influence of adding borax and modifying pH on effectiveness of food attractants for melon fly (Diptera: Tephritidae).

    PubMed

    Duyck, P F; Rousse, P; Ryckewaert, P; Fabre, F; Quilici, S

    2004-06-01

    The melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), is the most damaging pest of cucurbits in Reunion Island. The influence of adding borax and modifying pH on the effectiveness of different food attractants for both sexes of the melon fly is analyzed by a release-recapture method in field cages. Adding borax to protein hydrolysates Nulure and Buminal strongly reduced their attractiveness for B. cucurbitae. Acidification of 5% Buminal solution (from pH 6 to pH 3) doubled its attractiveness for melon fly. Conversely, Torula yeast at pH 10.5 was significantly more attractive than the standard Torula yeast at pH 9 (28% of captured flies compared with 17%). However, a further pH increase of the yeast solution does not improve its attractiveness. The results are discussed in relation to other studies on pH modification of various baits for Tephritidae.

  2. Borax methylene blue: a spectroscopic and staining study.

    PubMed

    Donaldson, P T; Russo, A; Reynolds, C; Lillie, R D

    1978-07-01

    Borax methylene blue is quite stable at room temperatures of 22-25 C. At 30 C polychroming is slow; during 50 days in a water bath at this temperature the absorption peak moves from 665 to 656 nm. At 35 C, the absorption peak reaches 660 nm in 7 days, 654 nm in 14. At 60 C polychroming is rapid, the absorption peak reaching 640-620 nm in 3 days. When the pH of the borax methylene blue solutions, normally about 9.0, is adjusted to pH 6.5, the absorption peak remains at 665 nm even when incubated at 60 C for extended periods. When used as a blood stain 0.4 ml borax methylene blue (1% methylene blue in 1% borax), 4 ml acetone, 2 ml borax-acid phosphate buffer to bring the solution to pH 6.5, and distilled water to make 40 ml, with 0.2 ml 1% eosin added just before using, an excellent Nocht-Giemsa type stain is achieved after 30 minutes staining. The material plasmodia P. falciparum, P. vivax, and P. berghei stain moderate blue with dark red chromatin and green to black pigment granules. The study confirms Malachowski's 1891 results and explains Gautier's 1896-98 failure to duplicate it.

  3. Peak distortion in the column liquid chromatographic determination of omeprazole dissolved in borax buffer.

    PubMed

    Arvidsson, T; Collijn, E; Tivert, A M; Rosén, L

    1991-11-22

    Injection of a sample containing omeprazole dissolved in borax buffer (pH 9.2) into a reversed-phase liquid chromatographic system consisting of a mixture of acetonitrile and phosphate buffer (pH 7.6) as the mobile phase and a C18 surface-modified silica as the solid phase resulted under special conditions in split peaks of omeprazole. The degree of peak split and the retention time of omeprazole varied with the concentration of borax in the sample solution and the ionic strength of the mobile phase buffer as well as with the column used. Borax is eluted from the column in a broad zone starting from the void volume of the column. The retention is probably due to the presence of polyborate ions. The size of the zone varies with the concentration of borax in the sample injected. In the borax zone the pH is increased compared with the pH of the mobile phase, and when omeprazole (a weak acid) is co-eluting in the borax zone its retention is affected. In the front part and in the back part of the borax zone, pH gradients are formed, and these gradients can induce the peak splitting. When the dissolving medium is changed to a phosphate buffer or an ammonium buffer at pH 9 no peak distortion of omeprazole is observed.

  4. 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.

  5. Respiratory effects of borax dust.

    PubMed

    Garabrant, D H; Bernstein, L; Peters, J M; Smith, T J; Wright, W E

    1985-12-01

    The relation of respiratory symptoms, pulmonary function, and abnormalities of chest radiographs to estimated exposures of borax dust has been investigated in a cross sectional study of 629 actively employed borax workers. Ninety three per cent of the eligible workers participated in the study and exposures ranged from 1.1 mg/m3 to 14.6 mg/m3. Symptoms of acute respiratory irritation such as dryness of the mouth, nose, or throat, dry cough, nose bleeds, sore throat, productive cough, shortness of breath, and chest tightness were related to exposures of 4.0 mg/m3 or more, and were infrequent at exposures of 1.1 mg/m3. Symptoms of persistent respiratory irritation meeting the definition of chronic simple bronchitis were related to exposure among non-smokers. Decrements in the FEV1 as a percentage of predicted were seen among smokers who had heavy cumulative borax exposures (greater than or equal to 80 mg/m3 years) but were not seen among less exposed smokers or among non-smokers. Radiographic abnormalities were uncommon and were not related to dust exposure. Borax dust appears to act as a simple respiratory irritant and perhaps causes small changes in the FEV1 among smokers who are heavily exposed.

  6. Cytotoxicity and negligible genotoxicity of borax and borax ores to cultured mammalian cells.

    PubMed

    Landolph, J R

    1985-01-01

    The cytotoxicity and genotoxicity of refined borax and borax ores were studied in cultured mammalian cells. In V79 Chinese hamster cells, C3H/10T1/2 mouse embryo fibroblasts, and diploid human foreskin fibroblasts, crude borax ore, kernite ore, and refined borax were all cytotoxic. The lowest concentrations at which cytotoxicity was observed were 0.02 mg/ml and 0.1 mg/ml for borax ore in C3H/10T1/2 and human fibroblasts, respectively, 0.2 mg/ml for kernite ore in both cell types, and 0.1 mg/ml for refined borax in both C3H/10T1/2 and human fibroblasts. The cytotoxicity was dose dependent above these concentrations. The concentrations of borax ore, kernite ore, and refined borax that reduced the relative plating efficiency to 50% were approximately 3.2, 1.6, and 0.8 mg/ml, respectively, in human fibroblasts and were 0.8 mg/ml for all three substances in C3H/10T1/2 cells. All three borax samples were not significantly mutagenic in assays for mutation to ouabain resistance in human fibroblasts an C3H/10T1/2 cells and were at most only weakly mutagenic in an assay for mutation to 8-azaguanine resistance in V79 Chinese hamster cells. Refined borax did not induce neoplastic transformation in C3H/10T1/2 cells. Crude borax ore and kernite ore induced weak transformation that was not dose-dependent and was not reproducible in another experiment. Therefore, borax and its ores are cytotoxic to mammalian cells at high (mg/ml) concentrations and are at most weakly mutagenic but not significantly oncogenic as measured in a cell transformation assay.

  7. [Infrared spectral analysis for calcined borax].

    PubMed

    Zhao, Cui; Ren, Li-Li; Wang, Dong; Zhou, Ping; Zhang, Qian; Wang, Bo-Tao

    2011-08-01

    To valuate the quality of calcined borax which is sold in the market, 18 samples of calcined borax were studied using the Fourier transform infrared, and samples with different water content were selected and analyzed. Then, the results of analysis were used to evaluate the quality of calcined borax. Results show that the infrared spectra of calcined borax include OH vibration, BO3(-3) vibration and BO4(5-) vibration absorption bands. The position and width of OH vibration absorption band depend on the level of water content, and the more the water content, the wider the absorption band. The number of BO3(3-) vibration and BO4(5-) vibration bands also depend on the level of water content, and the more the water content, and the stronger the hydrogen bond and the lower the symmetry of B atoms, the more the number of infrared absorption peaks. It was concluded that because the quality of calcined borax has direct correlation with water content, the infrared spectroscopy is an express and objective approach to quality analysis and evaluation of calcined borax.

  8. 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.

  9. Genotoxic effects of borax on cultured lymphocytes.

    PubMed

    Pongsavee, Malinee

    2009-03-01

    The effect of borax on human chromosomes was analyzed in this study. Venous blood from 30 male students at Thammasat University, Thailand (age 18-25 years) was collected for lymphocyte cell cultures. This experiment was divided into two groups: the first group was the control group and the second group was the experimental group. The lymphocyte cells in the control group were cultured without borax. The experimental group was divided into four subgroups. The lymphocyte cells in each experimental subgroup were cultured with different concentrations of borax (0.1 mg/ml, 0.15 mg/ml, 0.2 mg/ml and 0.3 mg/ml). Human chromosomes were studied for abnormalities through Giemsa-staining and G-banding. The results show that the numbers of metaphase plates (the metaphase plate which contained 46 chromosomes; 46, XY) and metaphase chromosomes were reduced when lymphocyte cells were cultured with 0.15 mg/ml (57.2%), 0.2 mg/ml (50.8%) and 0.3 mg/ml (42.3%) concentrations of borax. There was a statistically significant difference between the control and experimental subgroups (p < 0.05). Sister chromatid separation was found in the 0.3 mg/ml borax concentration experimental subgroup. This shows that borax (at 0.15, 0.2 and 0.3 mg/ml concentrations) affects the cell and human chromosomes (both numerical and structural abnormalities). Borax may cause human chromosome abnormalities and lead to genetic defects.

  10. 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.

  11. 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.

  12. 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...

  13. 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...

  14. 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....

  15. 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...

  16. [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.

  17. Seizure disorders and anemia associated with chronic borax intoxication.

    PubMed

    Gordon, A S; Prichard, J S; Freedman, M H

    1973-03-17

    During the course of investigation of two infants with seizure disorders it was discovered that both had been given large amounts of a preparation of borax and honey which resulted in chronic borate intoxication. In one child a profound anemia developed as well. The symptoms of chronic borate intoxication are different from those of the acute poisoning with which we are more familiar. The borax and honey preparations are highly dangerous and should no longer be manufactured or distributed for sale.

  18. 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.

  19. 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)

  20. 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....

  1. 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...

  2. 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....

  3. 40 CFR 436.130 - Applicability; description of the borax subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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...

  4. 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....

  5. 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....

  6. Seizure disorders and anemia associated with chronic borax intoxication

    PubMed Central

    Gordon, A. S.; Prichard, J. S.; Freedman, M. H.

    1973-01-01

    During the course of investigation of two infants with seizure disorders it was discovered that both had been given large amounts of a preparation of borax and honey which resulted in chronic borate intoxication. In one child a profound anemia developed as well. The symptoms of chronic borate intoxication are different from those of the acute poisoning with which we are more familiar. The borax and honey preparations are highly dangerous and should no longer be manufactured or distributed for sale. ImagesFIG. 1FIG. 2 PMID:4691106

  7. The rise and fall of borax as an antiepileptic drug.

    PubMed

    Jensen, John P A

    2006-04-01

    Five hundred eighty-six patients with epilepsy were treated with borax (hydrated sodium tetraborate) between 1912 and 1948 at the Kolonien Filadelfia Epilepsy Hospital, Dianalund, Denmark. A rough estimation shows that less than 5% experienced a more than 50% reduction in the total number of seizures. Charts were reviewed to find a connection between the concept of Bacillus epilepticus (1916) and the so-called renaissance of borax treatment described in 1923, and to find an explanation for the popularity of this seemingly ineffective antiepileptic drug.

  8. 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

  9. 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.

  10. Effects of boric acid and borax on titanium dioxide genotoxicity.

    PubMed

    Turkez, Hasan

    2008-07-01

    Titanium dioxide (TiO(2)) is a potential carcinogenic/mutagenic agent although it is used in many areas including medical industries and cosmetics. Boron (as boric acid and borax) has also well-described biological effects and therapeutic benefits. In a previous study, sister-chromatid exchanges (SCEs) and micronuclei (MN) rates were assessed in control and TiO(2)-treated (1, 2, 3, 5, 7.5 and 10 microm) human whole blood cultures. The results showed that the rates of SCE (at 2, 3, 5, 7.5 and 10 microm) and MN (at 5, 7.5 and 10 microm) formation in peripheral lymphocytes were increased significantly by TiO(2) compared with the controls. The present study also investigated the genetic effects of boric acid and borax (2.5, 5 and 10 microm) on cultures with and without TiO(2) addition. No significant increase in SCE and MN frequencies were observed at all concentrations of boron compounds. However, TiO(2)-induced SCE and MN could be reduced significantly by the presence of boric acid and borax. In conclusion, this study indicated for the first time that boric acid and borax led to an increased resistance of DNA to damage induced by TiO(2).

  11. Beneficiation of borax by reverse flotation in boron saturated brine.

    PubMed

    Cafer Cilek, Emin; Uresin, Hasan

    2005-10-15

    Flotation is one of the plausible methods for recovering borax fines discharged as fine waste to the tailings dam in the Kirka borax processing plant. A literature review dealing with the flotation behavior of boron minerals reveals that clay minerals in the boron ores coat boron minerals and thus deteriorate the quality of boron concentrates produced by direct flotation. The main objective of this study is therefore to recover borax fines from the tailings of the concentrator by reverse flotation. A three-level-factor experimental design was used to determine the main and interaction effects of variables selected on the metallurgical performance of reverse flotation. An analysis of variance for experimental results indicates that interaction effects of the variables for concentrate quality and recovery of B2O3 is nonsignificant and the most important variable for grade of concentrate and recovery is the collector dosage. It is shown that a concentrate assaying 11.25% B2O3 with 89.90% B2O3 recovery could be produced by means of single-stage (rougher) reverse flotation. Additionally, in order to produce a sufficient-quality concentrate, a multistage reverse flotation scheme involving rougher, scavenger, and two cleaners was devised. A final concentrate containing 23.47% B2O3 with 81.78% B2O3 recovery was obtained from these tests. The reverse flotation method can be thus considered as an important option for the beneficiation of borax fines.

  12. Dynamics of pH modification of an acidic protein bait used for tropical fruit flies (Diptera: Tephritidae).

    PubMed

    Heath, Robert R; Vazquez, Aime; Schnell, Elena Q; Villareal, Janett; Kendra, Paul E; Epsky, Nancy D

    2009-12-01

    Several species of Anastrepha and Bactrocera fruit flies (Diptera: Tephritidae) are captured in traps baited with the protein bait NuLure combined with borax (sodium tetraborate decahydrate) in an aqueous solution, typically 9% NuLure (vol:vol) with 3% borax (wt:vol). NuLure is an acid hydrolysate of corn and has an acidic pH. Addition of borax makes the solution more alkaline, and increase in alkalinity results in increase of ammonia release from the bait solution. This is a very dynamic system, with resultant pH affected by factors such as the amount of borax added, the pH of the water used for preparation, the age of the bait solution, and the development of microbial growth. Problems with borax include amount needed to increase alkalinity of NuLure solutions, which creates difficulties in disposing of spent bait in fruit fly trapping programs. Therefore, research was conducted to evaluate NaOH as an alternative method to increase alkalinity of NuLure solutions. Laboratory experiments compared effect of NaOH versus borax for pH modification on changes in pH and ammonia content of NuLure solutions over time. Although NuLure/NaOH solutions could be adjusted to a more alkaline pH than NuLure/borax solutions, borax plays a critical role in pH stability over time. However, the pH of NuLure/NaOH is stabilized when propylene glycol (10% vol:vol) was used to prepare the bait solution. The use of NaOH can provide an alternative to the use of borax to increase bait solution alkalinity. PMID:20069869

  13. Dynamics of pH modification of an acidic protein bait used for tropical fruit flies (Diptera: Tephritidae).

    PubMed

    Heath, Robert R; Vazquez, Aime; Schnell, Elena Q; Villareal, Janett; Kendra, Paul E; Epsky, Nancy D

    2009-12-01

    Several species of Anastrepha and Bactrocera fruit flies (Diptera: Tephritidae) are captured in traps baited with the protein bait NuLure combined with borax (sodium tetraborate decahydrate) in an aqueous solution, typically 9% NuLure (vol:vol) with 3% borax (wt:vol). NuLure is an acid hydrolysate of corn and has an acidic pH. Addition of borax makes the solution more alkaline, and increase in alkalinity results in increase of ammonia release from the bait solution. This is a very dynamic system, with resultant pH affected by factors such as the amount of borax added, the pH of the water used for preparation, the age of the bait solution, and the development of microbial growth. Problems with borax include amount needed to increase alkalinity of NuLure solutions, which creates difficulties in disposing of spent bait in fruit fly trapping programs. Therefore, research was conducted to evaluate NaOH as an alternative method to increase alkalinity of NuLure solutions. Laboratory experiments compared effect of NaOH versus borax for pH modification on changes in pH and ammonia content of NuLure solutions over time. Although NuLure/NaOH solutions could be adjusted to a more alkaline pH than NuLure/borax solutions, borax plays a critical role in pH stability over time. However, the pH of NuLure/NaOH is stabilized when propylene glycol (10% vol:vol) was used to prepare the bait solution. The use of NaOH can provide an alternative to the use of borax to increase bait solution alkalinity.

  14. 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

  15. Photonic crystal borax competitive binding carbohydrate sensing motif.

    PubMed

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

    2009-05-01

    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.

  16. 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.

  17. 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

  18. 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.

  19. Effect of borax on immune cell proliferation and sister chromatid exchange in human chromosomes

    PubMed Central

    Pongsavee, Malinee

    2009-01-01

    Background Borax is used as a food additive. It becomes toxic when accumulated in the body. It causes vomiting, fatigue and renal failure. Methods The heparinized blood samples from 40 healthy men were studied for the impact of borax toxicity on immune cell proliferation (lymphocyte proliferation) and sister chromatid exchange in human chromosomes. The MTT assay and Sister Chromatid Exchange (SCE) technic were used in this experiment with the borax concentrations of 0.1, 0.15, 0.2, 0.3 and 0.6 mg/ml. Results It showed that the immune cell proliferation (lymphocyte proliferation) was decreased when the concentrations of borax increased. The borax concentration of 0.6 mg/ml had the most effectiveness to the lymphocyte proliferation and had the highest cytotoxicity index (CI). The borax concentrations of 0.15, 0.2, 0.3 and 0.6 mg/ml significantly induced sister chromatid exchange in human chromosomes (P < 0.05). Conclusion Borax had effects on immune cell proliferation (lymphocyte proliferation) and induced sister chromatid exchange in human chromosomes. Toxicity of borax may lead to cellular toxicity and genetic defect in human. PMID:19878537

  20. Effect of borax on testis of Indian desert gerbil, Meriones hurriane Jerdon.

    PubMed

    Sharma, M P; Mathur, R S; Mehta, K

    1978-10-15

    Borax was injected at a dose level of 250 mg/kg b. wt for 16 days (total dose 4 g/kg b. wt) s.c. to active adult male gerbils. Borax caused several degenerative changes in the testes, of which giant cell formation, pyknosis and exfoliation are prominent. The increased activity of phosphatases was also noticed.

  1. Guar gum and scleroglucan interactions with borax: experimental and theoretical studies of an unexpected similarity.

    PubMed

    Bocchinfuso, Gianfranco; Mazzuca, Claudia; Sandolo, Chiara; Margheritelli, Silvia; Alhaique, Franco; Coviello, Tommasina; Palleschi, Antonio

    2010-10-21

    Guar gum is a galactomannan that assumes a very flexible conformation in solution, while Scleroglucan is a very rigid polysaccharide that dissolves in water as triple helices. Both polymers can form gels in the presence of borax. Despite their structural differences, the freeze-dried gel systems of both polymers, when compressed to form tablets, show a peculiar anisotropic swelling in water that reflects an amazing similarity in terms of their molecular properies. In this paper the behavior of the Guar/borax gel is compared with that of Scleroglucan/borax. The macroscopic properties of the two systems were characterized in terms of rheological measurements. Atomic force microscopy images and molecular dynamics simulation allowed to evaluate, at molecular level, the effect of borax addition to the Guar polymer. Both experiments show that an increasing of the polymer rigidity is produced by borax. The role played by galactose in the side chain was also discussed.

  2. 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.

  3. Drug delivery matrices based on scleroglucan/alginate/borax gels.

    PubMed

    Matricardi, Pietro; Onorati, Ilenia; Coviello, Tommasina; Alhaique, Franco

    2006-06-19

    The aim of this work is to obtain a new drug delivery matrix, especially designed for protein delivery, based on biodegradable and biocompatible polymers, and to describe its main physico-chemical properties. A polysaccharide based semi-interpenetrating polymer network (semi-IPN) was built up, composed by sodium alginate chains interspersed into a scleroglucan/borax hydrogel network. Tablets were obtained by compression of the resulting freeze-dried hydrogel. The different release and physico-chemical properties possessed by the two starting polymers in various aqueous media were combined in the new matrix. In this work, description is given of the in vitro ability of the matrix to deliver in a controlled manner a protein, Myoglobin, in distilled water, simulated gastric fluid and simulated intestinal fluid; the release, simulating a gastric passage, followed by an enteric delivery, was also carried out. Water uptake data, colorimetric experiments and scanning electron microscopy images are given for the characterization of this new solid dosage form; the importance of the borax presence is also discussed.

  4. Effect of sodium tetraborate (borax) on the thermal properties of frozen aqueous sugar and polyol solutions.

    PubMed

    Izutsu, Ken-ichi; Rimando, Annie; Aoyagi, Nobuo; Kojima, Shigeo

    2003-06-01

    The effect of sodium tetraborate (Na(2)B(4)O(7), borax) on the thermal property of frozen aqueous sugar and polyol solutions was studied through thermal analysis. Addition of borax raised the thermal transition temperature (glass transition temperature of maximally freeze-concentrated solutes; T(g)') of frozen sucrose solutions depending on the borax/sucrose concentration ratios. Changes in the T(g)' of frozen mono- and disaccharide solutions suggested various forms of complexes, including those of a borate ion and two saccharide molecules. Borax exerted the maximum effect to raise the oligosaccharide and dextran T(g)'s at borax/saccharide molar ratios of approximately 1-2 (maltose and maltooligosaccharides), 2 (dextran 1060), 5 (dextran 4900), and 10 (dextran 10200). Further addition of borax lowered T(g)'s of the saccharide solutions. Borax also raised T(g) and T(g)' temperatures of frozen aqueous glycerol solutions. The decreased solute mobility in frozen solutions by the borate-polyol complexes suggested higher collapse temperature in the freeze-drying process and improved stability of biological systems in frozen solutions.

  5. 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.

  6. Dual roles of borax in kinetics of calcium sulfate dihydrate formation.

    PubMed

    Jiang, Wenge; Pan, Haihua; Tao, Jinhui; Xu, Xurong; Tang, Ruikang

    2007-04-24

    An additive is not exclusively retardant or promoter for a crystallization system. The kinetic studies of calcium sulfate dihydrate (CSD) crystal growth demonstrated that borax played dual roles in the reaction, which accelerated CSD formations at the low concentration levels but inhibited the crystal growth at the high ones. In situ atomic force microscopy studies revealed that borax modulated the CSD crystallization via two different pathways: promoted the secondary nucleation to increase the step density on the growing crystal faces but simultaneously retarded the spread of these growth steps by the Langmuir adsorption. These two contradictory factors were incorporated in the crystallization, and their balance was regulated by the borax concentration. Both the macroscopic and microscopic experimental data nicely displayed the crystallization model of birth and spread that was able to account for the behaviors of borax in CSD formations.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. Iodometric microdetermination of boric acid and borax separately or in a mixture.

    PubMed

    Saxena, R; Verma, R M

    1983-05-01

    Boric acid is determined by first treating it with mannitol and then with solid potassium iodate and potassium iodide. The iodine liberated is titrated with thiosulphate. Borax is determined by reacting it with a known and excessive volume of hydrochloric acid and determining the surplus acid by iodometry. From the amount of acid consumed, the quantity of borax is calculated. Mixtures of borax and boric acid are analysed by combination of the two methods. Borax is determined first, then the mannitol procedure is applied to a second sample and the total boric acid (original plus that produced in the borax-HCl reaction) is determined iodometrically. The boric acid content of the sample is obtained by difference. The procedures can be used for determining 0.01-0.1 mmole of these substances with an average deviation of 0.1-0.4%. The end-points obtained are sharper than those for potentiometric acid-base titrations. Furthermore, the procedures are applicable at much lower concentrations.

  13. 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.

  14. 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.

  15. 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%.

  16. 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.

  17. A borax fusion technique for quantitative X-ray fluorescence analysis.

    PubMed

    Van Willigen, J H; Kruidhof, H; Dahmen, E A

    1971-04-01

    A borax fusion technique to cast glass discs for quantitative X-ray analysis is described in detail. The method is based on the "nonwetting" properties of a Pt/Au alloy towards molten borax, on the favourable composition of the flux and finally on the favourable form of the casting mould. The critical points of the technique are stressed, resulting in a method which could be carried out successfully by inexperienced workers. In general the method compares favourably in speed and accuracy with wet-chemical methods.

  18. The relationship of blood- and urine-boron to boron exposure in borax-workers and usefulness of urine-boron as an exposure marker.

    PubMed Central

    Culver, B D; Shen, P T; Taylor, T H; Lee-Feldstein, A; Anton-Culver, H; Strong, P L

    1994-01-01

    Daily dietary-boron intake and on-the-job inspired boron were compared with blood- and urine-boron concentrations in workers engaged in packaging and shipping borax. Fourteen workers handling borax at jobs of low, medium, and high dust exposures were sampled throughout full shifts for 5 consecutive days each. Airborne borax concentrations ranged from means of 3.3 mg/m3 to 18 mg/m3, measured gravimetrically. End-of-shift mean blood-boron concentrations ranged from 0.11 to 0.26 microgram/g; end-of-shift mean urine concentrations ranged from 3.16 to 10.72 micrograms/mg creatinine. Creatinine measures were used to adjust for differences in urine-specific gravity such that 1 ml of urine contains approximately 1 mg creatinine. There was no progressive increase in end-of-shift blood- or urine-boron concentrations across the days of the week. Urine testing done at the end of the work shift gave a somewhat better estimate of borate exposure than did blood testing, was sampled more easily, and was analytically less difficult to perform. Personal air samplers of two types were used: one, the 37-mm closed-face, two-piece cassette to estimate total dust and the other, the Institute of Occupational Medicine (IOM) sampler to estimate inspirable particulate mass. Under the conditions of this study, the IOM air sampler more nearly estimated human exposure as measured by blood- and urine-boron levels than did the sampler that measured total dust.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7889874

  19. The relationship of blood- and urine-boron to boron exposure in borax-workers and usefulness of urine-boron as an exposure marker.

    PubMed

    Culver, B D; Shen, P T; Taylor, T H; Lee-Feldstein, A; Anton-Culver, H; Strong, P L

    1994-11-01

    Daily dietary-boron intake and on-the-job inspired boron were compared with blood- and urine-boron concentrations in workers engaged in packaging and shipping borax. Fourteen workers handling borax at jobs of low, medium, and high dust exposures were sampled throughout full shifts for 5 consecutive days each. Airborne borax concentrations ranged from means of 3.3 mg/m3 to 18 mg/m3, measured gravimetrically. End-of-shift mean blood-boron concentrations ranged from 0.11 to 0.26 microgram/g; end-of-shift mean urine concentrations ranged from 3.16 to 10.72 micrograms/mg creatinine. Creatinine measures were used to adjust for differences in urine-specific gravity such that 1 ml of urine contains approximately 1 mg creatinine. There was no progressive increase in end-of-shift blood- or urine-boron concentrations across the days of the week. Urine testing done at the end of the work shift gave a somewhat better estimate of borate exposure than did blood testing, was sampled more easily, and was analytically less difficult to perform. Personal air samplers of two types were used: one, the 37-mm closed-face, two-piece cassette to estimate total dust and the other, the Institute of Occupational Medicine (IOM) sampler to estimate inspirable particulate mass. Under the conditions of this study, the IOM air sampler more nearly estimated human exposure as measured by blood- and urine-boron levels than did the sampler that measured total dust.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. 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.

  1. 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.

  2. Scleroglucan-borax hydrogel: a flexible tool for redox protein immobilization.

    PubMed

    Frasconi, Marco; Rea, Sara; Matricardi, Pietro; Favero, Gabriele; Mazzei, Franco

    2009-09-15

    A highly stable biological film was prepared by casting an aqueous dispersion of protein and composite hydrogel obtained from the polysaccharide Scleroglucan (Sclg) and borax as a cross-linking agent. Heme proteins, such as hemoglobin (Hb), myoglobin (Mb), and horseradish peroxidase (HRP), were chosen as model proteins to investigate the immobilized system. A pair of well-defined quasi-reversible redox peaks, characteristics of the protein heme FeII/FeIII redox couples, were obtained at the Sclg-borax/proteins films on pyrolytic graphite (PG) electrodes, as a consequence of the direct electron transfer between the protein and the PG electrode. A full characterization of the electron transfer kinetic was performed by opportunely modeling data obtained from cyclic voltammetry and square wave voltammetry experiments. The efficiency of our cross-linking approach was investigated by studying the influence of different borax groups percentage in the Sclg matrix, revealing the versatility of this hydrogel in the immobilization of redox proteins. The native conformation of the three heme proteins entrapped in the hydrogel films were proved to be unchanged, reflected by the unaltered Soret adsorption band and by the catalytic activity toward hydrogen peroxide (H2O2). The main kinetic parameters, such as the apparent Michaelis-Menten constant, for the electrocatalytic reaction were also evaluated. The peculiar characteristics of Sclg-borax matrix make it possible to find wide opportunities as proteins immobilizing agent for studies of direct electrochemistry and biosensors development.

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

    PubMed

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

    2011-03-01

    Ellagic acid (C(14)H(6)O(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.

  4. 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.

  5. 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

  6. 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

    2016-06-21

    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.

  7. 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.

  8. 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.

  9. 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.

  10. Borax mediated layer-by-layer self-assembly of neutral poly(vinyl alcohol) and chitosan.

    PubMed

    Manna, Uttam; Patil, Satish

    2009-07-01

    We report a multilayer film of poly(vinyl alcohol) (PVA)-borate complex and chitosan by using a layer-by-layer approach. PVA is an uncharged polymer, but hydroxyl functional groups of PVA can be cross-linked by using borax as a cross-linking agent. As a result electrostatic charges and intra- and interchain cross-links are introduced in the PVA chain and provide physically cross-linked networks. The PVA-borate was then deposited on a flat substrate as well as on colloidal particles with chitosan as an oppositely charged polyelectrolyte. Quartz crystal microbalance, scanning electron microscopy, and atomic force microscopy were used to follow the growth of thin film on flat substrate. Analogous experiments were performed on melamine formaldehyde colloidal particles (3-3.5 microm) to quantify the process for the preparation of hollow microcapsules. Removal of the core in 0.1 N HCl results in hollow microcapsules. Characterization of microcapsules by transmission electron microscopy revealed formation of stable microcapsules. Further, self-assembly of PVA-borate/chitosan was loaded with the anticancer drug doxorubicin, and release rates were determined at different pH values to highlight the drug delivery potential of this system.

  11. Glycerin Borax Treatment of Exfoliative Cheilitis Induced by Sodium Lauryl Sulfate: a Case Report

    PubMed Central

    2016-01-01

    This paper reports on the results of a case study of a 19-year-old female who presented to the Oral Medicine clinic with a chief complaint of scaly and peeling lips. The lesions had persisted on her lips for more than 7 years and were refractory to previous treatment. Her physician’s diagnosis was contact dermatitis. We diagnosed this patient as having exfoliative cheilitis (EC). A patch test using the toothpaste containing sodium lauryl sulfate (SLS) was positive and the patient discontinued using it. Instead, she started using a toothpaste not containing SLS. One year after treating her lesions with hydrogen peroxide mouthwash 1% and glycerin borax, a gradual improvement was observed until returning to normal. Glycerin borax was safe, low cost and simple to use in treatment of refractory exfoliative cheilitis. SLS may have been a precipitating factor in EC in this case. PMID:27789914

  12. 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.

  13. Application of Bathurin and borax in the biological control of Monomorium pharaonis in housing estates.

    PubMed

    Vobrázková, E; Vanková, J; Samsinák, K

    1976-05-01

    Of two apartment houses infested with ants of the species Monomorium pharaonis, one was treated with a biological, the other with a chemical substance. In the first case we used Bathurin in combination with borax at a concentration of 1.3% for both substances. In the first week, borax was added to the bait (minced beef), within the next three weeks, the bait was mixed with Bathurin. The procedure was repeated 5 times. After this period, we achieved complete control of the ants on the infested premises.--Our results obtained with the chemical substance (the insecticide Anthrix) were less successful. This indicates that the first method, although time-consuming and requiring a perfect collaboration with all inhabitants, is safer, because it leads to the complete eradication of ants in the infested premises.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. Association of reversible alopecia with occupational topical exposure to common borax-containing solutions.

    PubMed

    Beckett, W S; Oskvig, R; Gaynor, M E; Goldgeier, M H

    2001-04-01

    Boron is widely used in industrial materials, most frequently as the salt borax. Systemic exposure (eg, ingestion) to boron in boric acid been associated with reversible toxic alopecia among other manifestations. There is scant clinical literature on alopecia caused by topical exposure to boron. We observed a series of 3 patients in 2 workplaces who suffered reversible alopecia from cutaneous boron exposure. The scalp alopecia was global in 1 patient and patchy in 2 patients. Alopecia was completely reversed by elimination or reduction of exposure to boron-containing materials in all 3 patients. We conclude that occupational topical exposure to boron in solutions may cause reversible alopecia.

  2. 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.

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

    SciTech Connect

    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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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.

  14. 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

  15. 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.

  16. Redetermination of the borax structure from laboratory X-ray data at 145 K.

    PubMed

    Gainsford, Graeme J; Kemmitt, Tim; Higham, Caleb

    2008-04-23

    THE TITLE COMPOUND, SODIUM TETRABORATE DECAHYDRATE (MINERAL NAME: borax), Na(2)[B(4)O(5)(OH)(4)]·8H(2)O, has been studied previously using X-ray [Morimoto (1956). Miner. J.2, 1-18] and neutron [Levy & Lisensky (1978). Acta Cryst. B34, 3502-3510] diffraction data. The structure contains tetra-borate anions [B(4)O(5)(OH)(4)](2-) with twofold rotation symmetry, which form hydrogen-bonded chains, and [Na(H(2)O)(6)] octa-hedra that form zigzag chains [Na(H(2)O)(4/2)(H(2)O)(2/1)]. The O-H bond distances obtained from the present redetermination at 145 K are shorter than those in the neutron study by an average of 0.127 (19) Å.

  17. 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.

  18. 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.

  19. Structural and rheological characterization of Scleroglucan/borax hydrogel for drug delivery.

    PubMed

    Coviello, Tommasina; Coluzzi, Gina; Palleschi, Antonio; Grassi, Mario; Santucci, Eleonora; Alhaique, Franco

    2003-09-01

    The polysaccharide Scleroglucan, one of the most rigid polymers found in nature, can form a chemical/physical gel, in the presence of borax. The obtained hydrogel was loaded with three different model molecules (Theophylline, Vitamin B12 and Myoglobin) and then, after freeze-drying, was used as a matrix for tablets. The release profiles of the substances from the dosage forms were evaluated; the matrix appeared capable to modulate the diffusion of the chosen molecules, and different diffusion rates were observed, according to the different radii of the tested molecules. Interestingly, in the dissolution medium the matrix undergoes an anisotropic swelling taking place only in the axial direction, while a negligible radial variation occurs. The water uptake of the matrix occurs according to a Fickian process. Samples at two different polymer concentrations (0.7 and 2.3%, w/v) were characterized in terms of rheological and mechanical parameters and the properties were interpreted in terms of the molecular structure obtained by conformational analysis. The flow curves acquired in the viscoelasticity interval, show the effect of the borate ion in improving the resistance of the gel in comparison to the polymer alone. The evaluation of the moduli indicates that the system is viscoelastic, with an appreciable liquid component that increases as the polymer concentration decreases. Also the cohesion of the gel is higher in comparison to the Scleroglucan and is strongly dependent on temperature. The combination of experimental and theoretical conformational analysis approaches, allowed us to propose a model for the structure of the macromolecular network and to give an explanation to the anomalous swelling that was observed. It came out that the polymer can built up a channel structure, mediated via borax ion interaction, that can accommodate guest molecules of different size.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Scleroglucan/borax: characterization of a novel hydrogel system suitable for drug delivery.

    PubMed

    Coviello, T; Grassi, M; Lapasin, R; Marino, A; Alhaique, F

    2003-07-01

    A new hydrogel, with scleroglucan using borax as a crosslinker, has been prepared. The physical gel has been loaded with a model molecule (theophylline) and the release of the drug from the gel was evaluated. The same system was used to prepare tablets and the delivery of theophylline in different environmental conditions (HCl and SIF) was determined. A recent theoretical approach has been applied to the dissolution profiles obtained from the tablets and a satisfactory agreement has been found with the experimental data. Furthermore, the diffusion coefficient of the model molecule was evaluated according to a suitable strategy that was tested on two set of data obtained with different set-ups (permeation and diffusion experiments). A simplified mathematical approach allows to reduce the two-dimensional problem of the Fick's second law in a one-dimensional system leading to a much easier handling of the data without loosing the accuracy of the original problem in two dimensions. The characterization of the gel has been also carried out following the kinetics of swelling in terms of water uptake.

  8. 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

  9. A human health risk assessment of boron (boric acid and borax) in drinking water.

    PubMed

    Murray, F J

    1995-12-01

    A human health risk assessment was conducted to derive an appropriate safe exposure level in drinking water of inorganic boron-containing compounds (boric acid and borax). Several regulatory agencies have set or plan to set drinking water guidelines or standards for boron (B). Recent publication of reproductive and developmental toxicity studies by the National Toxicology Program prompted this risk assessment, along with the understanding that boron may be nutritionally essential. A rat developmental toxicity study with a NOAEL of 9.6 mg B/kg/day was selected as the pivotal study on which to base this risk assessment, since it represents the most sensitive endpoint of toxicity. A detailed evaluation of these and other studies allowed modifications of the default values for uncertainty factors to account for the pharmacokinetic similarities among species, the lack of metabolism of inorganic boron-containing compounds, the similarity of the toxicity profile across species, the quality of the toxicological database, and other factors according to the approach described by Renwick previously. Benchmark dose calculations were performed, and the results were in close agreement with the NOAEL selected for this risk assessment. The Reference Dose was calculated to be 0.3 mg B/kg/day, resulting in an acceptable daily intake of 18 mg B/day. Considering that the U.S. average dietary intake of boron is 1.5 mg B/day, 16.5 mg B/day could be available for drinking water or other exposures, if any. A preliminary review of boron data in the National Inorganic Radionuclide Survey by the EPA indicates the median boron level in U.S. drinking water supplies to be 0.031 mg B/liter, and most exposures are less than 2.44 mg B/liter (99th percentile). It is concluded that boron in U.S. drinking water would not be expected to pose any health risk to the public.

  10. 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.

  11. In vivo percutaneous absorption of boron as boric acid, borax, and disodium octaborate tetrahydrate in humans: a summary.

    PubMed

    Wester, R C; Hui, X; Maibach, H I; Bell, K; Schell, M J; Northington, D J; Strong, P; Culver, B D

    1998-01-01

    Literature from the first half of this century reports concern for toxicity from topical use of boric acid, but assessment of percutaneous absorption has been impaired by lack of analytical sensitivity. Analytical methods in this study included inductively coupled plasma-mass spectrometry, which now allows quantitation of percutaneous absorption of 10B in 10B-enriched boric acid, borax, and disodium octaborate tetrahydrate (DOT) in biological matrices. This made it possible, in the presence of comparatively large natural dietary boron intakes for the in vivo segment of this study, to quantify the boron passing through skin. Human volunteers were dosed with 10B-enriched boric acid, 5.0%, borax, 5.0%, or disodium octaborate tetrahydrate, 10% in aqueous solutions. Urinalysis, for boron and changes in boron isotope ratios, was used to measure absorption. Boric acid in vivo percutaneous absorption was 0.226 (SD = 0.125) mean percent dose, with flux and permeability constant (Kp) calculated at 0.009 microg/cm2/h and 1.9 x 10(-7) cm/h, respectively. Borax absorption was 0.210 (SD = 0.194) mean percent dose, with flux and Kp calculated at 0.009 microg/cm2/h and 1.8 x 10(-7) cm/h, respectively. DOT absorption was 0.122 (SD = 0.108) mean percent, with flux and Kp calculated at 0.01 microg/cm2/h and 1.0 x 10(-7) cm/h, respectively. Pretreatment with the potential skin irritant 2% sodium lauryl sulfate had no effect on boron skin absorption. These in vivo results show that percutaneous absorption of boron, as boric acid, borax, and disodium octaborate tetrahydrate, through intact human skin is low and is significantly less than the average daily dietary intake. This very low boron skin absorption makes it apparent that, for the borates tested, the use of gloves to prevent systemic uptake is unnecessary. These findings do not apply to abraded or otherwise damaged skin.

  12. 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.

  13. 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.

  14. 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.

  15. The effects of dietary boric acid and borax supplementation on lipid peroxidation, antioxidant activity, and DNA damage in rats.

    PubMed

    Ince, Sinan; Kucukkurt, Ismail; Cigerci, Ibrahim Hakki; Fatih Fidan, A; Eryavuz, Abdullah

    2010-07-01

    The aims of this study were to clarify the effects of high dietary supplementation with boric acid and borax, called boron (B) compounds, on lipid peroxidation (LPO), antioxidant activity, some vitamin levels, and DNA damage in rats. Thirty Sprague Dawley male rats were divided into three equal groups: the animals in the first group (control) were fed with a standard rodent diet containing 6.4 mg B/kg, and the animals in the experimental group were fed with a standard rodent diet added with a supra-nutritional amount of boric acid and borax (100 mg B/kg) throughout the experimental period of 28 days. The B compounds decreased malondialdehyde (MDA), DNA damage, the protein carbonyl content (PCO) level in blood, and glutathione (GSH) concentration in the liver, Cu-Zn superoxide dismutase (SOD), and catalase (CAT) activity in the kidney. The B compounds increased GSH concentration in blood and the vitamin C level in plasma. Consequently, our results demonstrate that B supplementation (100 mg/kg) in diet decreases LPO, and enhances the antioxidant defense mechanism and vitamin status. There are no differences in oxidant/antioxidant balance and biochemical parameters except for serum vitamin A and liver GSH concentration, between the boron compounds used in this study.

  16. 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.

  17. 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°).

  18. 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.

  19. 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.

  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. In vitro percutaneous absorption of boron as boric acid, borax, and disodium octaborate tetrahydrate in human skin: a summary.

    PubMed

    Wester, R C; Hartway, T; Maibach, H I; Schell, M J; Northington, D J; Culver, B D; Strong, P L

    1998-01-01

    Literature from the first half of this century reports concern for toxicity from topical use of boric acid, but assessment of percutaneous absorption has been impaired by lack of analytical sensitivity. Analytical methods in this study included inductively coupled plasma-mass spectrometry which now allows quantitation of percutaneous absorption of 10B in 10B-enriched boric acid, borax and disodium octaborate tetrahydrate (DOT) in biological matrices. In vitro human skin percent doses of boric acid absorbed were 1.2 for a 0.05% solution, 0.28 for a 0.5% solution, and 0.70 for a 5.0% solution. These absorption amounts translated into flux values of, respectively, 0.25, 0.58, and 14.58 microg/cm2/h, and permeability constants (Kp) of 5.0 x 10(-4), 1.2 x 10(-4), and 2.9 x 10(-4) cm/h for the 0.05%, 0.5%, and 5.0% solutions. The above in vitro doses were at infinite, 1000 microL/cm2 volume. At 2 microL/cm2 (the in vivo dosing volume), flux decreased some 200-fold to 0.07 microg/cm2/h and Kp of 1.4 x 10(-6) cm/h, while percent dose absorbed was 1.75%. Borax dosed at 5.0%/1000 microL/cm2 had 0.41 percent dose absorbed, flux at 8.5 microg/cm2/h, and Kp was 1.7 x 10(-4) cm/h. Disodium octaborate tetrahydrate (DOT) dosed at 10%/1000 microL/cm2 was 0.19 percent dose absorbed, flux at 7.9 microg/cm2/h, and Kp was 0.8 x 10(-4) cm/h. These in vitro results from infinite doses (1000 microL/cm2) were a 1000-fold greater than those obtained in the companion in vivo study. The results from the finite (2 microL/cm2) dosing were closer (10-fold difference) to the in vivo results. General application of infinite dose percutaneous absorption values for risk assessment is questioned by these results.

  2. 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

  3. 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

  4. 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.

  5. Comparison of the performance of the borax buffer-based HRP-enhanced reagent and the 'Lumi-Phos 530' chemiluminescence systems in the detection of biotinylated DNA.

    PubMed

    Cercek, B; Roby, K; Siaw, M

    1995-01-01

    A comparison of two chemiluminescence methods, the borax buffer-based HRP-enhanced reagent and Lumi-Phos 530, applied to the detection of a biotinylated 30-mer DNA slot blotted onto a nylon membrane, is presented. A streptavidin-HRP and streptavidin-ALP mediated detection system was used. The HRP-enhanced system is up to 15-fold greater with respect to the signal/background ratios than the Lumi-Phos 530 system at 0.5 microgram biotinylated DNA with at least a two-fold improvement in detection sensitivity for 0.5 ng biotinylated DNA.

  6. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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, Table 1 Table 1 to Subpart MM of Part 63—General Provisions Applicability to Subpart MM General...

  7. 40 CFR Table 1 to Subpart Mm of... - General Provisions Applicability to Subpart MM

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 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, Table 1 Table 1 to Subpart MM of Part 63—General Provisions Applicability to Subpart MM General...

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. A Toddler's Treatment of "Mm" and "Mm Hm" in Talk with a Parent

    ERIC Educational Resources Information Center

    Filipi, Anna

    2007-01-01

    The study to be reported in this paper examined the work accomplished by "mm" and "mm hm" in the interactions of a parent and his daughter aged 0;10-2;0. Using the findings of Gardner (2001) for adults, the analysis shows that "mm" accomplished a range of functions based on its sequential placement and prosodic features, whereas "mm hm" was much…

  13. Introduction to QM/MM simulations.

    PubMed

    Groenhof, Gerrit

    2013-01-01

    Hybrid quantum mechanics/molecular mechanics (QM/MM) simulations have become a popular tool for investigating chemical reactions in condensed phases. In QM/MM methods, the region of the system in which the chemical process takes place is treated at an appropriate level of quantum chemistry theory, while the remainder is described by a molecular mechanics force field. Within this approach, chemical reactivity can be studied in large systems, such as enzymes. In the first part of this contribution, the basic methodology is briefly reviewed. The two most common approaches for partitioning the two subsystems are presented, followed by a discussion on the different ways of treating interactions between the subsystems. Special attention is given on how to deal with situations in which the boundary between the QM and MM subsystems runs through one or more chemical bonds. The second part of this contribution discusses what properties of larger system can be obtained within the QM/MM framework and how. Finally, as an example of a QM/MM application in practice, the third part presents an overview of recent QM/MM molecular dynamics simulations on photobiological systems. In addition to providing quantities that are experimentally accessible, such as structural intermediates, fluorescence lifetimes, quantum yields and spectra, the QM/MM simulations also provide information that is much more difficult to measure experimentally, such as reaction mechanisms and the influence of individual amino acid residues.

  14. Resting pulmonary artery pressure of 21-24 mmHg predicts abnormal exercise haemodynamics.

    PubMed

    Lau, Edmund M T; Godinas, Laurent; Sitbon, Olivier; Montani, David; Savale, Laurent; Jaïs, Xavier; Lador, Frederic; Gunther, Sven; Celermajer, David S; Simonneau, Gérald; Humbert, Marc; Chemla, Denis; Herve, Philippe

    2016-05-01

    A resting mean pulmonary artery pressure (mPAP) of 21-24 mmHg is above the upper limit of normal but does not reach criteria for the diagnosis of pulmonary hypertension (PH). We sought to determine whether an mPAP of 21-24 mmHg is associated with an increased risk of developing an abnormal pulmonary vascular response during exercise.Consecutive patients (n=290) with resting mPAP <25 mmHg who underwent invasive exercise haemodynamics were analysed. Risk factors for pulmonary vascular disease or left heart disease were present in 63.4% and 43.8% of subjects. An abnormal pulmonary vascular response (or exercise PH) was defined by mPAP >30 mmHg and total pulmonary vascular resistance >3 WU at maximal exercise.Exercise PH occurred in 74 (86.0%) out of 86 versus 96 (47.1%) out of 204 in the mPAP of 21-24 mmHg and mPAP <21 mmHg groups, respectively (OR 6.9, 95% CI: 3.6-13.6; p<0.0001). Patients with mPAP of 21-24 mmHg had lower 6-min walk distance (p=0.002) and higher New York Heart Association functional class status (p=0.03). Decreasing levels of mPAP were associated with a lower prevalence of exercise PH, which occurred in 60.3%, 38.7% and 7.7% of patients with mPAP of 17-20, 13-16 and <13 mmHg, respectively.In an at-risk population, a resting mPAP between 21-24 mmHg is closely associated with exercise PH together with worse functional capacity. PMID:26965292

  15. 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.

  16. 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

  17. 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)

  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. 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.

  20. 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.

  1. Film Programmer's Guide to 16mm Rentals.

    ERIC Educational Resources Information Center

    Artel, Linda J., Ed.; Weaver, Kathleen, Ed.

    The guide is geared to reflect the expanding interest in the history of cinema, in underground and experimental films, in social and political documentaries as well as more conventional Hollywood and foreign classics. It lists over 8,000 16mm films selected from 50 United States distributors. A title directory contains information concerning the…

  2. CCM3 to MM5 Data Conversion

    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. In vivo percutaneous absorption of boric acid, borax, and disodium octaborate tetrahydrate in humans compared to in vitro absorption in human skin from infinite and finite doses.

    PubMed

    Wester, R C; Hui, X; Hartway, T; Maibach, H I; Bell, K; Schell, M J; Northington, D J; Strong, P; Culver, B D

    1998-09-01

    Literature from the first half of this century report concern for toxicity from topical use of boric acid, but assessment of percutaneous absorption has been impaired by lack of analytical sensitivity. Analytical methods in this study included inductively coupled plasma-mass spectrometry which now allows quantitation of percutaneous absorption of 10B in 10B-enriched boric acid, borax, and disodium octaborate tetrahydrate (DOT) in biological matrices. This made it possible, in the presence of comparatively large natural dietary boron intakes for the in vivo segment of this study, to quantify the boron passing through skin. Human volunteers were dosed with 10B-enriched boric acid, 5.0%, borax, 5.0%, or disodium octaborate tetrahydrate, 10%, in aqueous solutions. Urinalysis, for boron and changes in boron isotope ratios, was used to measure absorption. Boric acid in vivo percutaneous absorption was 0.226 (SD = 0.125) mean percentage dose, with flux and permeability constant (Kp) calculated at 0.009 microgram/cm2/h and 1.9 x 10(-7) cm/h, respectively. Borax absorption was 0.210 (SD = 0.194) mean percentage of dose, with flux and Kp calculated at 0.009 microgram/cm2/h and 1.8 x 10(-7) cm/h, respectively. DOT absorption was 0.122 (SD = 0.108) mean percentage, with flux and Kp calculated at 0.01 microgram/cm2/h and 1.0 x 10(-7) cm/h, respectively. Pretreatment with the potential skin irritant 2% sodium lauryl sulfate had no effect on boron skin absorption. In vitro human skin percentage of doses of boric acid absorbed were 1.2 for a 0.05% solution, 0.28 for a 0.5% solution, and 0.70 for a 5.0% solution. These absorption amounts translated into flux values of, respectively, 0.25, 0.58, and 14.58 micrograms/cm2/h and permeability constants (Kp) of 5.0 x 10(-4), 1.2 x 10(-4), and 2.9 x 10(-4) cm/h for the 0.05, 0.5, and 5.0% solutions. The above in vitro doses were at infinite, 1000 microliters/cm2 volume. At 2 microliters/cm2 (the in vivo dosing volume), flux decreased some

  5. Terahertz/mm wave imaging simulation software

    NASA Astrophysics Data System (ADS)

    Fetterman, M. R.; Dougherty, J.; Kiser, W. L., Jr.

    2006-10-01

    We have developed a mm wave/terahertz imaging simulation package from COTS graphic software and custom MATLAB code. In this scheme, a commercial ray-tracing package was used to simulate the emission and reflections of radiation from scenes incorporating highly realistic imagery. Accurate material properties were assigned to objects in the scenes, with values obtained from the literature, and from our own terahertz spectroscopy measurements. The images were then post-processed with custom Matlab code to include the blur introduced by the imaging system and noise levels arising from system electronics and detector noise. The Matlab code was also used to simulate the effect of fog, an important aspect for mm wave imaging systems. Several types of image scenes were evaluated, including bar targets, contrast detail targets, a person in a portal screening situation, and a sailboat on the open ocean. The images produced by this simulation are currently being used as guidance for a 94 GHz passive mm wave imaging system, but have broad applicability for frequencies extending into the terahertz region.

  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.

  7. 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

  8. 1 mm ultrafast superconducting stripline molecule detector

    NASA Astrophysics Data System (ADS)

    Zen, N.; Casaburi, A.; Shiki, S.; Suzuki, K.; Ejrnaes, M.; Cristiano, R.; Ohkubo, M.

    2009-10-01

    Superconducting stripline detectors (SSLDs) are promising for detecting keV molecules at nanosecond response times and with mass-independent detection efficiency. However, a fast response time is incompatible with practical centimeter detector size. A parallel configuration of striplines provides a means to address this problem. Experimental results and simulation for promisingly large 1-mm-square parallel niobium SSLDs show that nanosecond pulses are produced by superconducting-normal transition within only one of the parallel striplines instead of cascade switching of all the parallel striplines. Successful detection of a series of multimers of immunoglobulin G up to 584 kDa supports the mass-independent efficiency for mass spectrometry.

  9. 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.

  10. 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

  11. Coordinated mm/sub-mm observations of Sagittarius A* in May 2007

    NASA Astrophysics Data System (ADS)

    Kunneriath, D.; Eckart, A.; Vogel, S.; Sjouwerman, L.; Wiesemeyer, H.; Schödel, R.; Baganoff, F. K.; Morris, M.; Bertram, T.; Dovciak, M.; Dowries, D.; Duschl, W. J.; Karas, V.; Konig, S.; Krichbaum, T.; Krips, M.; Lu, R.-S.; Markoff, S.; Mauerhan, J.; Meyer, L.; Moultaka, J.; Muzic, K.; Najarro, F.; Schuster, K.; Straubmeier, C.; Thum, C.; Witzel, G.; Zamaninasab, M.; Zensus, A.

    2008-10-01

    At the center of the Milky Way, with a distance of thicksim8 kpc, the compact source Sagittarius A* (SgrA*) can be associated with a super massive black hole of thicksim4x 106Modot. SgrA* shows strong variability from the radio to the X-ray wavelength domains. Here we report on simultaneous NIR/sub-millimeter/X-ray observations from May 2007 that involved the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope, the Australian Telescope Compact Array (ATCA), the US mm-array CARMA, the IRAM 30m mm-telescope, and other telescopes. We concentrate on the time series of mm/sub-mm data from CARMA, ATCA, and the MAMBO bolometer at the IRAM 30m telescope.

  12. 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... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  13. 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... 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... Combustion Sources at Kraft, Soda, Sulfite, and Stand-Alone Semichemical Pulp Mills Pt. 63, Subpt. MM,...

  15. 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

  16. 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

  17. From the nm to the Mm

    NASA Astrophysics Data System (ADS)

    Villa, I. M.

    2003-12-01

    Tectonic models for the evolution of an orogen start at the Mm scale, and use field work on smaller subunits at the km scale and rocks collected at the m scale. At the mm scale, minerals are identified, analyzed by mass spectrometry, their "cooling ages" assigned to a specific closure temperature, a cooling rate attributed to a particular tectonic regime, and a large body of self-referential literature is the product of an oiled machinery. Problems become apparent if one attempts to harmonize mm-scale science with the nasty little details at even smaller scales. Atoms are invisible to the naked eye (unlike the minerals mentioned above) and their actual behavior is, or was, only accessible to indirect argumentations and simplified calculations. Increased computing power now allows calculating the transport of atoms in a crystal from the Schr”dinger equation: results do not fit 19th century continuum physics for infinitely dilute solutions (Fick's and Arrhenius' "laws"). Moreover, improved nanochemical analyses allow characterizing the supposedly homogeneous mineral matrix. TEM images show how layers or chains in pristine minerals are substituted in a non-periodic way by alteration products. EMP analyses show the almost ubiquitous presence of razor-sharp boundaries rather than Erf profiles. Disequilibrium recrystallization textures thus prevail over diffusive reequilibration; diffusion sensu stricto is shown to be a much slower process than heterochemical replacement. Alterability sequences are well known to surface scientists: e.g. halite, olivine, biotite, muscovite, zircon. Such sequences are reflected in the isotopic retentivity. The link only becomes clear at the nm scale: isotopic exchange occurs during the replacement reactions that affect all rocks on their retrograde P-T evolution. This is sufficient to explain why zircons record higher isotopic ages than muscovites, which in turn undergo less isotope exchange than biotites etc. While there is a vague

  18. The MM/PBSA and MM/GBSA methods to estimate ligand-binding affinities

    PubMed Central

    Genheden, Samuel; Ryde, Ulf

    2015-01-01

    Introduction: The molecular mechanics energies combined with the Poisson–Boltzmann or generalized Born and surface area continuum solvation (MM/PBSA and MM/GBSA) methods are popular approaches to estimate the free energy of the binding of small ligands to biological macromolecules. They are typically based on molecular dynamics simulations of the receptor–ligand complex and are therefore intermediate in both accuracy and computational effort between empirical scoring and strict alchemical perturbation methods. They have been applied to a large number of systems with varying success. Areas covered: The authors review the use of MM/PBSA and MM/GBSA methods to calculate ligand-binding affinities, with an emphasis on calibration, testing and validation, as well as attempts to improve the methods, rather than on specific applications. Expert opinion: MM/PBSA and MM/GBSA are attractive approaches owing to their modular nature and that they do not require calculations on a training set. They have been used successfully to reproduce and rationalize experimental findings and to improve the results of virtual screening and docking. However, they contain several crude and questionable approximations, for example, the lack of conformational entropy and information about the number and free energy of water molecules in the binding site. Moreover, there are many variants of the method and their performance varies strongly with the tested system. Likewise, most attempts to ameliorate the methods with more accurate approaches, for example, quantum-mechanical calculations, polarizable force fields or improved solvation have deteriorated the results. PMID:25835573

  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. 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.

  1. 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…

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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)

  9. 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.

  10. 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...

  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, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 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. 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).

  15. Production and characterization of an extracellular polysaccharide from Streptomyces violaceus MM72.

    PubMed

    Manivasagan, Panchanathan; Sivasankar, Palaniappan; Venkatesan, Jayachandran; Senthilkumar, Kalimuthu; Sivakumar, Kannan; Kim, Se-Kwon

    2013-08-01

    The isolation, optimization, purification and characterization of an extracellular polysaccharide (EPS) from a marine actinobacterium, Streptomyces violaceus MM72 were investigated. Medium composition and culture conditions for the EPS production by S. violaceus MM72 were optimized using two statistical methods: Plackett-Burman design applied to find the key ingredients and conditions for the best yield of EPS production and central composite design used to optimize the concentration of the three significant variables: glucose, tryptone and NaCl. The preferable culture conditions for EPS production were pH 7.0, temperature 35°C and NaCl concentration 2.0% for 120h with fructose and yeast extract as best carbon and nitrogen sources, respectively. The results showed that S. violaceus MM72 produced a kind of EPS having molecular weight of 8.96×10(5)Da. In addition, the EPS showed strong DPPH radical-scavenging activity, superoxide scavenging and metal chelating activities while moderate inhibition of lipid peroxidation and reducing activities determined in this study. These results showed the great potential of EPS produced by S. violaceus MM72 could be used in industry in place of synthetic compounds. The EPS from S. violaceus MM72 may be a new source of natural antioxidants with potential value for health, food and therapeutics. PMID:23597709

  16. 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

  17. 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…

  18. 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…

  19. 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)

  20. 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

  1. mm-wave radar - The new ECM-ECCM frontier

    NASA Astrophysics Data System (ADS)

    Johnston, S. L.

    1984-05-01

    The present investigation is concerned with the relationship of mm-wave radar to electronic countermeasures (ECM)/electronic counter-countermeasures (ECCM). Electronic warfare support measures (ESM) are also considered, since employment of ECM against mm-wave radar places strong demands on ESM. The mm-waves are defined as wavelengths in the range from 1 to 10 mm corresponding to frequencies in the range from 300 to 30 GHz. Advantages of mm-waves over microwaves for radar applications are partly related to requirements for smaller antenna diameters, increased angular resolution/antenna diameter, increased bandwidth availability, increased range resolution, reduced vulnerability to unwanted detection by hostile forces, and smaller and lighter RF components.

  2. Simple fibre optic spectrophotometric cell for pH determination.

    PubMed

    Besar, S S; Kelly, S W; Greenhalgh, P A

    1989-03-01

    A simple, inexpensive fibre optic spectrophotometric cell has been developed for clinical use. The system may employ one of two indicator reagents for the measurement: phenol red and BDH universal indicator. The spectrophotometer uses two ultrabright LED sources and a PIN diode photodetector. The fibre is of the plastic type with a core diameter of 1.0 mm. Two alternative analytical methods are available: electronic or computer processing. In the case of phenol red the measuring range using computer processing is between 6.0 and 8.0 pH units, with an accuracy of 0.015 pH units. The range for electronic circuit processing is from 6.8 to 8.0 pH units with an accuracy of 0.02 pH units. Using a BDH universal indicator, the range for computer processing is between 5.5 and 8.5 pH units with an accuracy of 0.05 pH units, while with electronic processing the range is between 6.0 and 8.0 pH units with an accuracy of 0.03 pH units. A description of the optoelectronics, an analysis of the indicator reagents and the calibration procedure are presented here, together with some example results. PMID:2704218

  3. 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).

  4. 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…

  5. 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)

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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

  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 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

  14. 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

  15. Electromagnetic launch of mm-size pellets to great velocities

    SciTech Connect

    Drobyshevski, E.M.; Zhukov, B.G.; Kurakin, R.O.; Sakharov, V.A.; Studenkov, A.M.

    1994-11-01

    Small body launching that uses gas or plasma faces the fundamental problem caused by excess energy loss that is due to the great wall surface/volume ratio of the barrel. For example, the efficiency of the plasma armature (PA) rail-gun acceleration is maximum for 8-10 mm-size bodies and drops as their size decreases. That is why in the case of nuclear fusion applications, where 1-2 mm-size pellets at 5-10 km/s velocity are desirable, electromagnetic launchers have not yet demonstrated an advantage over light-gas guns and one is now forced to search for a compromise between the pellet size (increasing it up to 3-4 mm) and its velocity (decreasing it down to {approx}3 km/s). As a whole, the probability of attaining 5-10 km/s velocity for 1-2 mm pellets seems to be rather remote at the present.

  16. ALMA 1.3 mm observations of the Fomalhaut System

    NASA Astrophysics Data System (ADS)

    White, Jacob; Boley, Aaron C.; Ford, Eric B.; Payne, Matthew John; Dent, William; Corder, Stuartt

    2016-10-01

    We present ALMA Band 6 (1.3 mm) observations of Fomalhaut and its debris disk. Since the system is relatively close at 7.7 pc, it has been the target of numerous studies at multiple wavelengths, and can serve as a testbed for debris disk evolution models and planet-disk interactions. Outstanding issues that need to be resolved to properly characterize the debris include tightening constraints on the spectral index in the submm/mm regime and determining whether there is indeed excess over the stellar emission, indicating the presence of an inner debris disk or ring.These ALMA 1.3 mm observations provide the highest resolution observations to date of the mm grains the outer ring. Tight constraints are placed on the geometry of the disk and on the mm-wavelength spectral index. We explore fitting the debris disk model in the image plane in addition to the standard method of fitting the visibilities. The results are compared and potential advantages/disadvantages of each approach are discussed.The central emission detected is indistinguishable from a point source, with 0.89 mJy being the best fit flux of the host star for Fomalhaut itself. This implies that any inner debris component must contribute little to the total central emission. Moreover, the stellar flux is less than 70% of that predicted by extrapolating a blackbody from the constrained photosphere temperature and just over 70% of the flux if extrapolating from the far infrared. This behavior is similar to that seen in the Sun for submm/mm wavelengths, but even more pronounced. Currently, insufficient data exists to properly constrain the degree to which stellar atmospheres affect the observed flux in the submm/mm regime. This result is part of an ongoing larger project focused on measuring the emission from stellar atmospheres at submm/mm wavelengths, which directly impacts inferred excesses for debris disk studies.

  17. [Degradation of oil derivatives by Acinetobacter calcoaceticus MM5].

    PubMed

    Marín, M M; Ortiz, M L; Laborda, F

    1994-01-01

    This paper describes the isolation of microorganisms from polluted heating oil. The growth of one of them has been studied (Acinetobacter calcoaceticus MM5) in several linear and branched hydrocarbons as well as the effect of its growth on commercial diesel oil. Acinetobacter calcoaceticus MM5 is not capable of using glucose as its only source of carbon, and it needs the presence of nitrogen and phosphorus sources to degrade any petroleum by-product.

  18. Extracellular pH modulates GABAergic neurotransmission in rat hypothalamus.

    PubMed

    Chen, Z L; Huang, R Q

    2014-06-20

    Changes in extracellular pH have a modulatory effect on GABAA receptor function. It has been reported that pH sensitivity of the GABA receptor is dependent on subunit composition and GABA concentration. Most of previous investigations focused on GABA-evoked currents, which only reflect the postsynaptic receptors. The physiological relevance of pH modulation of GABAergic neurotransmission is not fully elucidated. In the present studies, we examined the influence of extracellular pH on the GABAA receptor-mediated inhibitory neurotransmission in rat hypothalamic neurons. The inhibitory postsynaptic currents (IPSCs), tonic currents, and the GABA-evoked currents were recorded with whole-cell patch techniques on the hypothalamic slices from Sprague-Dawley rats at 15-26 postnatal days. The amplitude and frequency of spontaneous GABA IPSCs were significantly increased while the external pH was changed from 7.3 to 8.4. In the acidic pH (6.4), the spontaneous GABA IPSCs were reduced in amplitude and frequency. The pH induced changes in miniature GABA IPSCs (mIPSCs) similar to that in spontaneous IPSCs. The pH effect on the postsynaptic GABA receptors was assessed with exogenously applied varying concentrations of GABA. The tonic currents and the currents evoked by sub-saturating concentration of GABA ([GABA]) (10 μM) were inhibited by acidic pH and potentiated by alkaline pH. In contrast, the currents evoked by saturating [GABA] (1mM) were not affected by pH changes. We also investigated the influence of pH buffers and buffering capacity on pH sensitivity of GABAA receptors on human recombinant α1β2γ2 GABAA receptors stably expressed in HEK 293 cells. The pH influence on GABAA receptors was similar in HEPES- and MES-buffered media, and not dependent on protonated buffers, suggesting that the observed pH effect on GABA response is a specific consequence of changes in extracellular protons. Our data suggest that the hydrogen ions suppress the GABAergic neurotransmission

  19. Effects of pH on contraction of rabbit fast and slow skeletal muscle fibers.

    PubMed Central

    Chase, P B; Kushmerick, M J

    1988-01-01

    We have investigated (a) effects of varying proton concentration on force and shortening velocity of glycerinated muscle fibers, (b) differences between these effects on fibers from psoas (fast) and soleus (slow) muscles, possibly due to differences in the actomyosin ATPase kinetic cycles, and (c) whether changes in intracellular pH explain altered contractility typically associated with prolonged excitation of fast, glycolytic muscle. The pH range was chosen to cover the physiological pH range (6.0-7.5) as well as pH 8.0, which has often been used for in vitro measurements of myosin ATPase activity. Steady-state isometric force increased monotonically (by about threefold) as pH was increased from pH 6.0; force in soleus (slow) fibers was less affected by pH than in psoas (fast) fibers. For both fiber types, the velocity of unloaded shortening was maximum near resting intracellular pH in vivo and was decreased at acid pH (by about one-half). At pH 6.0, force increased when the pH buffer concentration was decreased from 100 mM, as predicted by inadequate pH buffering and pH heterogeneity in the fiber. This heterogeneity was modeled by net proton consumption within the fiber, due to production by the actomyosin ATPase coupled to consumption by the creatine kinase reaction, with replenishment by diffusion of protons in equilibrium with a mobile buffer. Lactate anion had little mechanical effect. Inorganic phosphate (15 mM total) had an additive effect of depressing force that was similar at pH 7.1 and 6.0. By directly affecting the actomyosin interaction, decreased pH is at least partly responsible for the observed decreases in force and velocity in stimulated muscle with sufficient glycolytic capacity to decrease pH. Images FIGURE 1 PMID:2969265

  20. 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

    ... case of products blended with some portion of biomass-based fuel, the carbon share in Table MM-1 of... biomass should not be reported, but products that were derived from both biomass and a petroleum...

  1. Effects of pH and Sugar on Acetoin Production from Citrate by Leuconostoc lactis.

    PubMed

    Cogan, T M; O'dowd, M; Mellerick, D

    1981-01-01

    The relationship between acetoin production and citrate utilization in Leuconostoc lactis NCW1 was studied. In a complex medium the organism utilized citrate at neutral pH (initial pH, 6.3) and at acid pH (initial pH, 4.5) but produced nine times more acetoin at the latter pH. In resting cells the utilization of citrate was optimum at pH 5.3. Production of acetoin as a function of citrate utilization increased as the pH decreased, and at pH 4.3 all of the citrate utilized was recovered as acetoin. Glucose (10 mM) and lactose (10 mM) markedly stimulated citrate utilization but totally inhibited acetoin production in glucose- and lactose-grown cells. Addition of glucose to cells actively metabolizing citrate caused an immediate increase in citrate uptake and a reduction in the level of acetoin. The apparent K(m) values of lactic dehydrogenase for pyruvate were 1.05, 0.25, and 0.15 mM at pH 7.5, 6.5, and 5.0, respectively. Several heterofermentation intermediates inhibited alpha-acetolactate synthetase and decarboxylase activities. The implications of these results in regulating acetoin formatin are discussed.

  2. 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).

  3. 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.

  4. 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.

  5. 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

  6. New Methods for Exploring QM:MM Potential Energy Landscapes

    NASA Astrophysics Data System (ADS)

    Hratchian, Hrant P.

    2010-06-01

    In recent years, the applicability of quantum chemical methods for large system studies has been greatly enhanced by the development of hybrid QM:MM techniques. Despite these advancements, exploring the associated potential energy surfaces continues to present two key challenges. First, the QM energy and derivative evaluations may be too costly for simulations; and second, the system size for many QM:MM cases are too large to effectively store or use second-order information, an approach often used in QM studies to allow for larger integration steps and fewer QM evaluations of the potential energy surface. Our most recent work is focused on overcoming both computational bottlenecks. Using surface fitting models together with direct Hessian-vector and diagonalization algorithms, we are developing models that can accurately and efficiently explore QM:MM potential energy landscapes for very large systems. Our current development status and results from initial applications will be described.

  7. 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)

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. Bell & Howell Introduces an 8mm Cartridge Concept

    ERIC Educational Resources Information Center

    Educ Screen Audiovisual Guide, 1970

    1970-01-01

    "Bell & Howell has developed a highly versatile cartidge projector system for cine and super 8mm formats. Because Bell & Howell believes that standardization is an important factor in the development of a cartridge system, it has built in a flexibility which will allow this standardization. (Author)

  14. 8mm Film in Education: Status and Prospects--1968.

    ERIC Educational Resources Information Center

    Forsdale, Louis

    An overwhelming deterrent to the use of film in the classroom has been the inaccessibility of the films and the complicated projectors required to show them. Eight-millimeter film has the potential to lower the cost of films, making them more accessible, and to make showing them vastly simpler. This paper traces the development of 8mm film use in…

  15. Public Library Subject Headings for 16MM Motion Pictures, 1971.

    ERIC Educational Resources Information Center

    California Library Association, Sacramento.

    A subject heading list for 16 millimeter motion pictures is proposed here that is designed to provide audiovisual librarians with a tool which will aid them in making subject indexes for their printed film catalogs and to establish an authority for professional catalogers who may be called upon to catalog 16 mm. motion pictures. In preparing the…

  16. 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 ...

  17. 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…

  18. 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…

  19. 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.

  20. 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…

  1. Use of MM-Paths in constructive software development

    SciTech Connect

    Jorgensen, P.C.

    1985-01-01

    Systems such as nuclear reactors, weapons systems, and real-time switching systems present a variety of problems for conventional software development. In addition to the sheer magnitude of these systems, high reliability requirements and deep complexities best characterized by Petri nets demand improvements in specification, design, and testing. Specification of such systems is considered: traditional functional decomposition is shown to be inadequate, as is the approach based on Finite State Machines. A rigorous form of process descriptions is developed here; these are demonstrated to have the same expressive power as Petri nets. Use of these process descriptions as a specification technique leads naturally to a truly intermediate level concept, the MM-path, which is the basis of the development methodology proposed here. This methodology is highly constructive in the sense that information needed in later phases is used to populate a database structured by the process description and MM-Path concepts. Sample queries are given to illustrate the use of the database in the software testing phases. Test coverage metrics are developed for the unit, integration, and system levels of software testing. Existing unit test coverage metrics are shown to be upper bounds to the unit test coverage metrics defined here. A lattice of four integration test coverage metrics is defined in terms of MM-Paths, and MM-Paths are used to extend the concepts of path analysis to system level testing.

  2. 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

  3. Conjugate heat transfer analysis of 300-mm bake station

    NASA Astrophysics Data System (ADS)

    Ramanan, Natarajan; Liang, Frank F.; Sims, James B.

    1999-06-01

    An exhaustive heat-transfer analysis of 200-mm and 300-mm bake equipment has been conducted to infer the temperature uniformity on the wafer from the time it is set on the plate until the end of the bake process. The objective of the analysis was to gain insight into the heat transport to the wafer and improve the thermal uniformity of the wafer. During the soft, hard and post-exposure bake processes, the temperatures to which the wafer is heated can range from 50 degrees to 250 degrees C. The influence of the variables that contribute to the temperature nonuniformity, namely the height of the proximity pins, wafer warp and bow, heater thickness, insulation of the bake plate, and lid material, have been analyzed. The analysis has been carried out using computational fluid dynamics packages, FLUENT/UNS and FIDAP. The accuracy of the numerical simulations has been verified through analytical solution is presented which provides a closed-form expression for the temperature of the wafer in terms of Biot number, a dimensionless parameter. The temperature rise of the wafer based on this simple expression compares very favorably with the detailed axisymmetric numerical solution that was carried out using variable material properties and the complex boundary conditions for the geometry of a 200-mm bake plate. The radial temperature variation on the wafer after 100 seconds on the bake plate also matches very well with the measurements. Based on the success of the modeling results with the 200-mm bake plates, a 300-mm bake plate analysis was conducted to determine if the temperature uniformity would be within specifications. The analysis revealed some key factors that caused temperature nonuniformity and the design was then altered to improve the temperature uniformity. Subsequent measurements confirmed the improvement of the temperature uniformity.

  4. 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

  5. 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

    ... some portion of biomass-based fuel, the carbon share in Table MM-1 of this subpart represents only the petroleum-based components. 2 Products that are derived entirely from biomass should not be reported, but products that were derived from both biomass and a petroleum product (i.e., co-processed) should...

  6. 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.

  7. 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

  8. Six-mm, plane-wave shock driver

    NASA Astrophysics Data System (ADS)

    Frank, Alan M.; Chau, Henry H.

    1994-07-01

    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 250 ns, with time-to-burst jitter under 10 ns. Both the slapper impact and the detonation breakout of the pellet have been measured to be flat to within 10 ns 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.

  9. 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.

  10. Six-mm, plane-wave shock driver

    SciTech Connect

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

    1994-07-10

    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 250 ns, with time-to-burst jitter under 10 ns. Both the slapper impact and the detonation breakout of the pellet have been measured to be flat to within 10 ns 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. [copyright]American Institute of Physics

  11. 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.

  12. [Enforcement of type M 20 cal. 4 mm cartridges].

    PubMed

    Dobosz, Tadeusz; Jaworski, Ryszard; Kawecki, Jerzy; Semiczek, Wiesław; Trnka, Jakub

    2002-01-01

    The aim of the paper was to investigate and compare the speed and energy of a bullet from 4 mm cal. cartridges of central ignition type M20, both original and transformed by addition of different kinds of propellants. Original cartridges are characterized by an average speed of the bullet of 144 m/s and average energy of 4.8 J. After transformation by the addition of on an average 31.3 mg of smokeless powder from a cartridge type LR'22, a maximum bullet speed of 299 m/s (average) and maximum energy of 21.2 joule (average) were reached. Our test showed that shots using transformed ammunition type M 20 cal. 4 mm can be dangerous for both health and life. Multiple M20 shot wounds may be very similar to single shot wounds caused by a shotshell cartridge fired from a shotgun weapon.

  13. 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

  14. 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.

  15. Cherenkov maser operation at lower-mm wavelengths

    SciTech Connect

    Garate, E.; Cook, R.; Heim, P.; Layman, R.; Walsh, J.

    1985-07-15

    The basic operating principles of Cerenkov maser oscillations are briefly reviewed and the experimental performance of a 3-mm device is discussed. A power level of approximately 100kW was achieved at 88 GHz and voltage tuning from 84 to 128 GHz on the fundamental TM01 mode was observed. Operation on higher-order modes at frequencies up to 300-320 GHz was demonstrated, and a two-stage buncher-amplifier configuration was investigated.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. The LLNL 150-mm equation-of-state gun system

    SciTech Connect

    Rienecker, F.; Honodel, C.; Waldron, R.; Moor, E.; Perfect, S.; Bast, R.

    1987-09-22

    Lawrence Livermore National Laboratory is currently designing a large gun system for expanded studies of a wide range of materials, including samples of high explosives weighing up to 10 kg. In its initial configuration, the system will have a 150-mm bore, 20-m-long, single-stage gun that can fire a 10-kg projectile at velocities of 2.2 km/s. Future plans include conversion either to a two-stage gun, or to a single-stage 100-mm gun, and conversion to a ballistic range. The high-explosive samples will be contained in a stainless steel tank that is 3.8 m in diameter, 12.5-m long, and 89-mm thick. This paper emphasizes improvements in the gun design, including tube couplings that use large coupling nuts and elastic interference fits to achieve precise alignment, a rail support system that allows rapid changes of configuration without need for re-alignment, and a barrel venting experiment designed to reduce projectile tilt in free flight. In addition, the authors discuss a computer modeling experiment in which they examined the effects of stress and strain on one part of the gun, the breech. Results showed that peak stresses would cause the breech to deform, producing autofrettaged conditions.

  2. 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)

  3. Lambmeat colour values (HunterLab CIE and reflectance) are influenced by aperture size (5 mm v. 25 mm).

    PubMed

    Holman, Benjamin W B; Ponnampalam, Eric N; van de Ven, Remy J; Kerr, Matthew G; Hopkins, David L

    2015-02-01

    The effect of aperture size on the assessment of lamb meat colour values (L*, a*, b* and R630/580)was investigated. Two experiments using 2 HunterLab MiniScan colorimeters (large [25 mm] and small [5 mm] apertures) were conducted: 1) coloured tiles were measured and 2) unaged lamb (n = 65) m. longissimus lumborum (LL) and m. semimembranosus (SM) muscles were measured over 2.5 d under simulated retail display. For Experiment three, 2 different colorimeters were used on lamb (n = 36) LL aged for 6 weeks before measurement over 4 don simulated retail display. Coloured tile a* and b* values were unaffected by aperture size, but L* values and the R630/580 ratio were influenced by aperture size. The effect of aperture size on lamb meat colour measurements varied with display time and muscle type. The large aperture size generally provided the highest colorimetric values, and is recommended for measuring lamb meat colour.

  4. Insights into structure and redox potential of lignin peroxidase from QM/MM calculations.

    PubMed

    Castro, Ludovic; Crawford, Luke; Mutengwa, Archford; Götze, Jan P; Bühl, Michael

    2016-02-28

    Redox potentials are computed for the active form (compound I) of lignin peroxidase (LiP) using a suitable QM/MM methodology (B3LYP/SDD/6-311G**//BP86/SVP:CHARMM). Allowing for dynamic conformational averaging, a potential of 0.67(33) V relative to ferrocenium/ferrocene is obtained for the active form with its oxoiron(iv) core. The computed redox potential is very sensitive to the charge distribution around the active site: protonation of titratable residues close to the metal center increases the redox potential, thereby rationalising the known pH dependence of LiP activity. A simple MM-charge deletion scheme is used to identify residues that are critical for the redox potential. Two mutant proteins are studied through homology modelling, E40Q and D183N, which are predicted to have an increased redox potential by 140 mV and 190 mV, respectively, relative to the wild type. These mutant proteins are thus promising targets for synthesis and further exploration toward a rational design of biocatalytic systems for oxidative degradation of lignin.

  5. FT-Raman and QM/MM study of the interaction between histamine and DNA

    NASA Astrophysics Data System (ADS)

    Ruiz-Chica, A. J.; Soriano, A.; Tuñón, I.; Sánchez-Jiménez, F. M.; Silla, E.; Ramírez, F. J.

    2006-05-01

    The interaction between histamine and highly polymerized calf-thymus DNA has been investigated using FT-Raman spectroscopy and the hybrid QM/MM (quantum mechanics/molecular mechanics) methodology. Raman spectra of solutions containing histamine and calf-thymus DNA, at different molar ratios, were recorded. Solutions were prepared at physiological settings of pH and ionic strength, using both natural and heavy water as the solvent. The analysis of the spectral changes on the DNA Raman spectra when adding different concentrations of histamine allowed us to identify the reactive sites of DNA and histamine, which were used to built two minor groove and one intercalated binding models. They were further used as starting points of the QM/MM theoretical study. However, minimal energy points were only reached for the two minor groove models. For each optimized structure, we calculated analytical force constants of histamine molecule in order to perform the vibrational dynamics. Normal mode descriptions allowed us to compare calculated wavenumbers for DNA-interacting histamine to those measured in the Raman spectra of DNA-histamine solutions.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. The Intracellular pH of Clostridium paradoxum, an Anaerobic, Alkaliphilic, and Thermophilic Bacterium

    PubMed Central

    Cook, G. M.; Russell, J. B.; Reichert, A.; Wiegel, J.

    1996-01-01

    When the extracellular pH was increased from 7.6 to 9.8, Clostridium paradoxum, a novel alkalithermophile, increased its pH gradient across the cell membrane ((Delta)pH, pH(infin) - pH(infout)) by as much as 1.3 U. At higher pH values (>10.0), the (Delta)pH and membrane potential ((Delta)(psi)) eventually declined, and the intracellular pH increased significantly. Growth ceased when the extracellular pH was greater than 10.2 and the intracellular pH increased to above 9.8. The membrane potential increased to 110 (plusmn) 8.6 mV at pH 9.1, but the total proton motive force ((Delta)p) declined from about 65 mV at pH 7.6 to 25 mV at pH 9.8. Between the extracellular pH of 8.0 and 10.3, the intracellular ATP concentration was around 1 mM and decreased at lower and higher pH values concomitantly with a decrease in growth rate. PMID:16535469

  12. pH gradients induced by urea metabolism in 'artificial mouth' microcosm plaques.

    PubMed

    Sissons, C H; Wong, L; Hancock, E M; Cutress, T W

    1994-06-01

    Evidence was sought for urea-induced pH gradients in dental plaque microcosm biofilms cultured from the mixed salivary bacteria in a multi plaque 'artificial mouth'. Application of 500 mmol/l urea for short periods (6 min) to 5-8 mm maximum-thickness plaques induced intraplaque pH gradients of up to 0.7 pH units with the surface alkaline relative to the inner plaque. These pH gradients persisted for more than 5 h in the absence of a flow of fluid. With 30-min urea applications and a flow of a basal medium containing mucin (BMM, pH 7.0), the pH of the inner (deeper) plaque regions also increased. Although the pH gradient initially formed was alkaline at the plaque surface, the BMM flow lowered the surface pH to neutrality whilst the inner layers were still alkaline, thereby reversing the pH gradient. In thick microcosm dental plaques, urea-induced pH gradients can therefore form and last many hours. They probably result from the significant time taken for urea to penetrate to the inner layers of plaque, its rapid metabolism by the outer plaque layers, and a rate-limiting clearance of ammonia. Even a slow BMM flow over the plaque greatly increased the rate of return to the resting pH, causing the gradients to change polarity.

  13. Influence of external pH and Fermentation products on Clostridium acetobutylicum intracellular pH and cellular distribution of fermentation products

    SciTech Connect

    Huang, L.; Forsberg, C.W.; Gibbins, L.N.

    1986-06-01

    Clostridium acetobutylicum ATCC 824 cells harvested from a phosphate-limited chemostat culture maintained pH 4.5 had intracellular concentrations of acetate, butyrate, and butanol which were 13-, 7-, and 1.3-fold higher, respectively, than the corresponding extracellular concentrations. Cells from a culture grown at pH 6.45 had intracellular concentrations of acetate and butyrate which were only 2.2-fold higher than the respective external concentrations. The highest intracellular concentrations to these acids were attained at ca. pH 5.5. When cells were suspended in anaerobic citrate-phosphate suffer at pH 4.5, exogenous acetate and butyrate caused a concentration-dependent decrease in the intracellular pH, while butanol had relatively little effect until the external concentration reached 150 mM. Acetone had no effect at concentrations up to 200 mM. These data demonstrate that acetate and butyrate are concentrated within the cell under acidic conditions and thus tend to lower the intracellular pH. The high intracellular butyrate concentration presumably leads to induction of solvent production, thereby circumventing a decrease in the intracellular pH great enough to be deleterious to the cell.

  14. 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.

  15. 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

  16. Robotic QM/MM-driven maturation of antibody combining sites

    PubMed Central

    Smirnov, Ivan V.; Golovin, Andrey V.; Chatziefthimiou, Spyros D.; Stepanova, Anastasiya V.; Peng, Yingjie; Zolotareva, Olga I.; Belogurov, Alexey A.; Kurkova, Inna N.; Ponomarenko, Natalie A.; Wilmanns, Matthias; Blackburn, G. Michael; Gabibov, Alexander G.; Lerner, Richard A.

    2016-01-01

    In vitro selection of antibodies from large repertoires of immunoglobulin (Ig) combining sites using combinatorial libraries is a powerful tool, with great potential for generating in vivo scavengers for toxins. However, addition of a maturation function is necessary to enable these selected antibodies to more closely mimic the full mammalian immune response. We approached this goal using quantum mechanics/molecular mechanics (QM/MM) calculations to achieve maturation in silico. We preselected A17, an Ig template, from a naïve library for its ability to disarm a toxic pesticide related to organophosphorus nerve agents. Virtual screening of 167,538 robotically generated mutants identified an optimum single point mutation, which experimentally boosted wild-type Ig scavenger performance by 170-fold. We validated the QM/MM predictions via kinetic analysis and crystal structures of mutant apo-A17 and covalently modified Ig, thereby identifying the displacement of one water molecule by an arginine as delivering this catalysis. PMID:27774510

  17. 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.

  18. Polyamine stress at high pH in Escherichia coli K-12

    PubMed Central

    Yohannes, Elizabeth; Thurber, Amy E; Wilks, Jessica C; Tate, Daniel P; Slonczewski, Joan L

    2005-01-01

    Background Polyamines such as spermine and spermidine are required for growth of Escherichia coli; they interact with nucleic acids, and they bind to ribosomes. Polyamines block porins and decrease membrane permeability, activities that may protect cells in acid. At high concentrations, however, polyamines impair growth. They impair growth more severely at high pH, probably due to their increased uptake as membrane-permeant weak bases. The role of pH is critical in understanding polyamine stress. Results The effect of polyamines was tested on survival of Escherichia coli K-12 W3110 in extreme acid or base (pH conditions outside the growth range). At pH 2, 10 mM spermine increased survival by 2-fold, and putrescine increased survival by 30%. At pH 9.8, however, E. coli survival was decreased 100-fold by 10 mM spermine, putrescine, cadaverine, or spermidine. At pH 8.5, spermine decreased the growth rate substantially, whereas little effect was seen at pH 5.5. Spermidine required ten-fold higher concentrations to impair growth. On proteomic 2-D gels, spermine and spermidine caused differential expression of 31 different proteins. During log-phase growth at pH 7.0, 1 mM spermine induced eight proteins, including PykF, GlpK, SerS, DeaD, OmpC and OmpF. Proteins repressed included acetate-inducible enzymes (YfiD, Pta, Lpd) as well as RapA (HepA), and FabB. At pH 8.5, spermine induced additional proteins: TnaA, OmpA, YrdA and NanA (YhcJ) and also repressed 17 proteins. Four of the proteins that spermine induced (GlpK, OmpA, OmpF, TnaA) and five that were repressed (Lpd, Pta, SucB, TpiA, YfiD) show similar induction or repression, respectively, in base compared to acid. Most of these base stress proteins were also regulated by spermidine, but only at ten-fold higher concentration (10 mM) at high pH (pH 8.5). Conclusion Polyamines increase survival in extreme acid, but decrease E. coli survival in extreme base. Growth inhibition by spermine and spermidine requires neutral or

  19. New thermostable amylase from Bacillus cohnii US147 with a broad pH applicability.

    PubMed

    Ghorbel, Raoudha Ellouz; Maktouf, Sameh; Massoud, Ezedine Ben; Bejar, Samir; Chaabouni, Semia Ellouz

    2009-04-01

    A new thermophilic bacterial strain identified as Bacillus cohnii US147 was isolated from the southern Tunisian soil. The identification was based on physiological tests and molecular techniques related to the 16S ribosomal ribonucleic acid. The isolated strain produced amylase, which was purified. This amylase had an apparent molecular mass of 30 kDa as estimated by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. Amylase US147 showed K (m) and V (max) values of 0.7 mg/ml and 2.2 U/ml, respectively, with starch as the substrate. The enzyme was active in acid and basic pH and had a maximal activity on starch at pH 9 and 70 degrees C. The enzyme was stable at pH 9 for 72 h and retained half of its activity after incubation at 70 degrees C for 150 min. A partially inhibition (15%, 25%, 23%, 20%, and 22%) was obtained with 1 mM SDS, 1 mM NaBO(3), 1 mM H(2)O(2,) 1 mM Zn(+2), and 5 mM ethylenediamine tetraacetic acid (EDTA), respectively. The amylase recovered its original activity by the addition of 10 mM Ca (2+) to the 5 mM EDTA. These properties indicated a possible use of this amylase in starch saccharification, in detergent, and in other industrial applications.

  20. Group 2 PH: Medical Therapy.

    PubMed

    Guazzi, Marco; Labate, Valentina

    2016-01-01

    Pulmonary hypertension (PH) secondary to left heart disease, classified as Group 2, is a widely underestimated target of therapy. Prevention and treatment of initial subclinical stages are not valued as a priority in the management of this chronic disease population, whereas attention is high for PH consequences in patients with advanced heart failure (HF) requiring a left ventricular mechanical assist device or heart transplant candidates. Even so, there is a growing interest toward the evidence of a clinical and prognostic role of PH in the elderly populations and in HF with preserved ejection fraction (HFpEF). Certainly, along with a prevalence definition not yet defined, the search for effective pharmacological approaches that might favorably affect the aging process and the natural history of HFpEF from earlier stages is not an easy task. Pharmacological studies that have tested some traditional pulmonary arterial hypertension approved drugs (i.e., prostanoids and endothelin-1 receptor blockers) primarily in PH and HF with reduced ejection fraction have not been positive, especially because of concomitant side effects, i.e., systemic hypotension, fluid retention and hepatic toxicity. In recent years, interest has moved toward drugs overexpressing the nitric oxide (NO)-cyclic guanosine monophosphate pathway with recent availability of well-tolerated selective pulmonary vasodilators, such as phosphodiesterase type 5 inhibitors and guanylate cyclase stimulators. Single center studies performed with these drugs have shown good tolerability and safety profile providing alternating hemodynamic results mainly because of recruitment of patients at different stages of the pulmonary vascular disease. Nonetheless, the overexpression of NO pathway appears to remain the most solid background for targeting lung microvessel dysfunction and treating RV dysfunction since the earliest stages of the disease. PMID:27389809

  1. 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

  2. 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.

  3. Experimental investigation of a mm-wave planar antenna

    NASA Astrophysics Data System (ADS)

    Lambrakakis, Georgios D.

    1990-06-01

    This thesis investigates a new mm-wave Bilateral Slot Line (BSL) antenna and its relation to the Linearly Tapered Slot Antenna (LTSA). The BSL antenna consists of a tapered double-sided slotline and can be viewed as two identical LTSAs sandwiched back to back. Dielectric substrates with permittivities of 2.33 and 6.0 were used to construct these antennas. The theoretical background, the design, and the performance in the frequency range 5 to 9 GHz of the new microwave integrated circuit antenna is presented. The effects of several parameters such as dielectric constant, stripline and slotline characteristic impedance, antenna structure, and transition scheme on the radiation patterns and return loss were experimentally investigated. Some relationships between the width of stripline and slotline, their characteristic impedance and the dielectric constant are reported. Guidelines are laid to design the LTSA and BSL antennas.

  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. 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.

  7. 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).

  8. 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

  9. 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.

  10. Radio and mm-observations of active nuclei

    NASA Astrophysics Data System (ADS)

    Biermann, P.

    Radio, mm-wave, and X ray observations of active galactic nuclei are reviewed, together with theoretical models for the phenomena. Formulas are defined for the power law energy distribution of relativistic electrons observed near the sources, the characteristic radio emission, the local emission coefficient, and electron energy loss. Consideration is also given to nonsynchrotron self-absorption and to international cooperation to coordinate radio telescopy on different continents to perform VLBI research. Most sources detected at low frequencies exhibit a steep spectrum halo, while flat spectrum sources at 5 GHz show little extended emission. The low frequency cut-offs encountered due to thermal absorption by H II regions are quantified. Injection and equilibrium spectra are examined, along with the synchrotron loss time scale, the inverse Compton limit, and evidence for repeated explosions in the nuclei. Finally, recent work at the Bonn radioastronomy facility is described.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 7 mm continuum observations of ultra compact HII regions

    NASA Astrophysics Data System (ADS)

    Leto, P.; Umana, G.; Trigilio, C.; Buemi, C. S.; Dolei, S.; Manzitto, P.; Cerrigone, L.; Siringo, C.

    2009-12-01

    Aims: Ultra compact HII (UCHII) regions are indicators of high-mass star formation sites and are distributed mainly in the Galactic plane. They exhibit a broad band spectrum with significant emission between near-IR and radio wavelengths. We intend to investigate the possible contribution of the forthcoming ESA Planck mission to the science of UCHII regions by evaluating the possibility of detecting UCHIIs that are bright in the radio regime. Methods: We performed new 7 mm observations of a sample of UCHII regions. The observations were designed to acquire high-frequency radio spectra. For each source in our sample, the free-free radio spectrum has been modeled. Along with far-IR measurements, our spectra allow us to estimate the flux densities of the sources in the millimeter and sub-millimeter bands. We extrapolated and summed the ionized-gas (free-free radio emission) and dust (thermal emission) contributions in the afore mentioned wavelength ranges. The possibility of Planck detecting the selected sources can be assessed by comparing the estimated flux densities to the expected sensitivity in each Planck channel. To obtain a realistic estimation of the noise produced by the Galactic emission, the Planck sky model software package was used. Results: For each target source, from our new 7 mm data and other radio measurements from the literature, important physical parameters such as electron density and their spatial distribution, source geometry and emission measure were derived. We conclude that, in the case of the present sample, located close to the Galactic center, Planck will have a very low detection rate. In contrast, assuming that our sample is representative of the whole UCHII-region population, we derive a very high probability of detecting this kind of source with Planck if located instead close to the anticenter. From the analysis of the ionized-gas properties, we suggest that the selected sample could also be contaminated by other kinds of Galactic

  16. Photodynamic therapy for Barrett's esophagus using a 20-mm diameter light-delivery balloon

    NASA Astrophysics Data System (ADS)

    Panjehpour, Masoud; Overholt, Bergein F.; Phan, Mary N.; Haydek, John M.; Robinson, Amy R.

    2002-06-01

    Background and Objective: Patients with high grade dysplasia (HGD) in Barrett's esophagus are at a high risk for developing esophageal adenocarcinoma. Esophagectomy is the standard treatment for such patients. The objective of this study was to evaluate the safety and efficacy of photodynamic therapy (PDT) using an improved light delivery balloon for ablation of Barrett's esophagus with high grade dysplasia and/or early cancer. Materials and Methods: 20 patients with HGD or early cancer (19 with HGD, 1 with T1 cancer) received 2 mg/kg of porfimer sodium, intravenously. Two to three days after the injection, laser light was delivered using a cylindrical diffuser inserted inside a 20-mm diameter reflective esophageal PDT balloon. Initially, the balloon was inflated to a pressure of 80 mm Hg. The balloon pressure was gradually reduced to 30 mm Hg. A KTP/dye laser at 630 nm was used as the light source. Light dose of 115 J/cm was delivered at an intensity of 270 mw/cm. Nodules were pre- treated with an extra 50 J/cm using a short diffuser inserted through the scope. Patients were maintained on PPI therapy to keep the gastric pH higher than 4. Eighteen patients required one treatment, while two patients were treated twice. Follow-up consisted of endoscopy with four quadrant biopsies at every 2 cm of the treated area. Thermal ablation was used to treat small residual islands on the follow-ups. The follow-up endoscopies ranged from 6 to 17 months. Results: On follow-up endoscopy, 12 patients had complete replacement of their Barrett's mucosa with neosquamous mucosa. Five patients had residual non-dysplastic Barrett's mucosa, one had indefinite dysplasia, two had low grad dysplasia. There were no residual HGD or cancers. The average length of Barrett's was reduced from 5.4 cm to 1.2 cm. High balloon pressure resulted in wide variation in PDT response among patients. Lower balloon pressures resulted in more consistent destruction of Barrett's mucosa among patients. Five

  17. Production of solvents by Clostridium acetobutylicum cultures maintained at neutral pH

    SciTech Connect

    Holt, R.A.; Stephens, G.M.; Morris, J.G.

    1984-12-01

    The formation of acetone and n-butanol by Clostridium acetobutylicum NCIB 8052 (ATCC 824) was monitored in batch culture at 35 degrees C in n of acetone and n-butanol by Clostridium acetobutylicum NCIB 8052 (ATCC 824) was monitored in batch culture at 35 degrees C in a glucose (2% (wt/vol)) minimal medium maintained throughout at either pH 5.0 or 7.0. At pH 5, good solvent production was obtained in the unsupplemented medium, although addition of acetate plus butyrate (10 mM each) caused solvent production to be initiated at a lower biomass concentration. At pH 7, although a purely acidogenic fermentation was maintained in the unsupplemented medium, low concentrations of acetone and n-butanol were produced when the glucose content of the medium was increased (to 4% (wt/vol)). Substantial solvent concentrations were, however, obtained at pH 7 in the 2% glucose medium supplemented with high concentrations of acetate plus butyrate (100 mM each, supplied as their potassium salts). Thus, Clostridium acetobutylicum NCIB 8052, like Clostridium beijerinckii VPI 13436, is able to produce solvents at neutral pH, although good yields are obtained only when adequately high concentrations of acetate and butyrate are supplied. Supplementation of the glucose minimal medium, with propionate (20 mM) at pH 5 led to the production of some n-propanol as well as acetone and n-butanol; the final culture medium was virtually acid free. At pH 7, supplementation with propionate (150 mM) again led to the formation of n-propanol but also provoked production of some acetone and n-butanol, although in considerably smaller amounts than were obtained when the same basal medium had been fortified with acetate and butyrate at pH 7.

  18. Disruption of the transmembrane pH gradient--a possible mechanism for the antibacterial action of azelaic acid in Propionibacterium acnes and Staphylococcus epidermidis.

    PubMed

    Bojar, R A; Cunliffe, W J; Holland, K T

    1994-09-01

    The effect of the topical acne treatment azelaic acid on the transmembrane proton gradient (delta pH) of Propionibacterium acnes and Staphylococcus epidermidis was studied in vitro at external pH values found on human skin (pH 4.0-6.0). Bacteria were grown in defined media using continuous culture and delta pH was estimated by measuring the accumulation of [14C] benzoic by the cells using flow dialysis. In both P. acnes and S. epidermidis the addition of 30 mM azelaic acid and the membrane active inhibitors nigericin (150 microM) and CCCP (150 microM) resulted in a rapid release of [14C] label into the dialysate indicating the dissipation of delta pH between external pH values of 4.0-6.0. The addition of 60 mM NaCl as an iso-osmotic control and 150 microM valinomycin did not induce the release of [14C] label. The addition of 30 mM azelaic acid reduced the delta pH of P. acnes by 44% at external pH 4.0 and 28% at external pH 6.0. In S. epidermidis 30 mM azelaic acid reduced delta pH by 88% at external pH 5.0 and 20% at external pH 6.0. Rapid loss of viability occurred in suspensions of P. acnes and S. epidermidis containing 30 mM azelaic acid at pH 4.0 with no viable cells recovered after 60 min incubation. At pH 6.0 little change in viable numbers of P. acnes and S. epidermidis were observed over a 2 h incubation period. The results indicate that the antibacterial activity of azelaic acid is associated with the perturbation of intracellular pH.

  19. Disruption of the transmembrane pH gradient--a possible mechanism for the antibacterial action of azelaic acid in Propionibacterium acnes and Staphylococcus epidermidis.

    PubMed

    Bojar, R A; Cunliffe, W J; Holland, K T

    1994-09-01

    The effect of the topical acne treatment azelaic acid on the transmembrane proton gradient (delta pH) of Propionibacterium acnes and Staphylococcus epidermidis was studied in vitro at external pH values found on human skin (pH 4.0-6.0). Bacteria were grown in defined media using continuous culture and delta pH was estimated by measuring the accumulation of [14C] benzoic by the cells using flow dialysis. In both P. acnes and S. epidermidis the addition of 30 mM azelaic acid and the membrane active inhibitors nigericin (150 microM) and CCCP (150 microM) resulted in a rapid release of [14C] label into the dialysate indicating the dissipation of delta pH between external pH values of 4.0-6.0. The addition of 60 mM NaCl as an iso-osmotic control and 150 microM valinomycin did not induce the release of [14C] label. The addition of 30 mM azelaic acid reduced the delta pH of P. acnes by 44% at external pH 4.0 and 28% at external pH 6.0. In S. epidermidis 30 mM azelaic acid reduced delta pH by 88% at external pH 5.0 and 20% at external pH 6.0. Rapid loss of viability occurred in suspensions of P. acnes and S. epidermidis containing 30 mM azelaic acid at pH 4.0 with no viable cells recovered after 60 min incubation. At pH 6.0 little change in viable numbers of P. acnes and S. epidermidis were observed over a 2 h incubation period. The results indicate that the antibacterial activity of azelaic acid is associated with the perturbation of intracellular pH. PMID:7829407

  20. Effect of pH and ionic strength on the physicochemical properties of coconut milk emulsions.

    PubMed

    Tangsuphoom, N; Coupland, J N

    2008-08-01

    Coconut milk (16% to 17% fat, 1.8% to 2% protein) was extracted from coconut (Cocos nucifera L.) endosperm and diluted in buffer to produce natural oil-in-water emulsions (10 wt% oil). The effect of pH (3 to 7) and NaCl (0 to 200 mM) on the properties and stability, namely, mean particle size, zeta-potential, viscosity, microstructure, and creaming stability, of the natural coconut milk emulsions was investigated. At pH values close to the isoelectric point (IEP) of the coconut proteins (pH 3.5 to 4) and in the absence of NaCl, coconut milk flocculated, but did not coalesce. Flocculation corresponded to low surface charges and was accompanied by an increase in emulsion viscosity. Adding up to 200 mM NaCl to those flocculated emulsions did not change the apparent degree of flocculation. Coconut milk emulsion at pH 6 was negatively charged and not flocculated. Upon addition of salt, the zeta-potential decreased from -16 to -6 mV (at 200 mM NaCl) but this was not sufficient to induce flocculation in coconut milk emulsions. At low pH (< IEP), the positively charged droplets of coconut milk emulsions only flocculated when the NaCI concentration exceeded 50 mM, as the zeta-potential approached zero.

  1. Effect of pH and ionic strength on the physicochemical properties of coconut milk emulsions.

    PubMed

    Tangsuphoom, N; Coupland, J N

    2008-08-01

    Coconut milk (16% to 17% fat, 1.8% to 2% protein) was extracted from coconut (Cocos nucifera L.) endosperm and diluted in buffer to produce natural oil-in-water emulsions (10 wt% oil). The effect of pH (3 to 7) and NaCl (0 to 200 mM) on the properties and stability, namely, mean particle size, zeta-potential, viscosity, microstructure, and creaming stability, of the natural coconut milk emulsions was investigated. At pH values close to the isoelectric point (IEP) of the coconut proteins (pH 3.5 to 4) and in the absence of NaCl, coconut milk flocculated, but did not coalesce. Flocculation corresponded to low surface charges and was accompanied by an increase in emulsion viscosity. Adding up to 200 mM NaCl to those flocculated emulsions did not change the apparent degree of flocculation. Coconut milk emulsion at pH 6 was negatively charged and not flocculated. Upon addition of salt, the zeta-potential decreased from -16 to -6 mV (at 200 mM NaCl) but this was not sufficient to induce flocculation in coconut milk emulsions. At low pH (< IEP), the positively charged droplets of coconut milk emulsions only flocculated when the NaCI concentration exceeded 50 mM, as the zeta-potential approached zero. PMID:19241548

  2. Alkaline pH sensor molecules.

    PubMed

    Murayama, Takashi; Maruyama, Ichiro N

    2015-11-01

    Animals can survive only within a narrow pH range. This requires continual monitoring of environmental and body-fluid pH. Although a variety of acidic pH sensor molecules have been reported, alkaline pH sensor function is not well understood. This Review describes neuronal alkaline pH sensors, grouped according to whether they monitor extracellular or intracellular alkaline pH. Extracellular sensors include the receptor-type guanylyl cyclase, the insulin receptor-related receptor, ligand-gated Cl- channels, connexin hemichannels, two-pore-domain K+ channels, and transient receptor potential (TRP) channels. Intracellular sensors include TRP channels and gap junction channels. Identification of molecular mechanisms underlying alkaline pH sensing is crucial for understanding how animals respond to environmental alkaline pH and how body-fluid pH is maintained within a narrow range.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. Cleanroom compatible anodization cell for 150 mm Si wafers

    NASA Astrophysics Data System (ADS)

    Bardwell, Jennifer A.; LeBrun, Les; Evans, R. James; Curry, Donald G.; Abbott, Roger

    1996-06-01

    A cleanroom compatible anodization cell for use with 150 mm Si wafers has been constructed and tested. The material of construction is polyvinylidene fluoride, Kynar■, with Chemraz■ (elastomeric polytetrafluoroethylene) O-rings used for sealing. The back contact is made through a dilute HF solution, thus eliminating the possibility for metallic contamination which exists for other forms of back contact. Pt electrodes immersed in the back contact and front contact solutions are the primary electrical connection sites. Ellipsometry, Fourier transform infrared spectroscopy (FTIR), and dilute HF etch rate experiments were used to characterize the as-grown and annealed anodic oxides produced in this cell. Ellipsometric thickness mapping showed excellent lateral oxide uniformity over the entire anodized area; the standard deviations were <2 Å (for oxides ≤100 Å in thickness), <6 Å (for oxides ≤400 Å in thickness), and <10 Å (for oxides <500 Å in thickness). The properties of the oxides, as evaluated by FTIR spectroscopy are essentially identical to those grown on small-area samples using conventional anodization with a metallic back contact.

  8. 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.

  9. rf breakdown tests of mm-wave metallic accelerating structures

    NASA Astrophysics Data System (ADS)

    Dal Forno, Massimo; Dolgashev, Valery; Bowden, Gordon; Clarke, Christine; Hogan, Mark; McCormick, Doug; Novokhatski, Alexander; Spataro, Bruno; Weathersby, Stephen; Tantawi, Sami G.

    2016-01-01

    We are exploring the physics and frequency-scaling of vacuum rf breakdowns at sub-THz frequencies. We present the experimental results of rf tests performed in metallic mm-wave accelerating structures. These experiments were carried out at the facility for advanced accelerator experimental tests (FACET) at the SLAC National Accelerator Laboratory. The rf fields were excited by the FACET ultrarelativistic electron beam. We compared the performances of metal structures made with copper and stainless steel. The rf frequency of the fundamental accelerating mode, propagating in the structures at the speed of light, varies from 115 to 140 GHz. The traveling wave structures are 0.1 m long and composed of 125 coupled cavities each. We determined the peak electric field and pulse length where the structures were not damaged by rf breakdowns. We calculated the electric and magnetic field correlated with the rf breakdowns using the FACET bunch parameters. The wakefields were calculated by a frequency domain method using periodic eigensolutions. Such a method takes into account wall losses and is applicable to a large variety of geometries. The maximum achieved accelerating gradient is 0.3 GV /m with a peak surface electric field of 1.5 GV /m and a pulse length of about 2.4 ns.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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).

  16. 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.

  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. 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

  19. 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

  20. 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 ...

  1. The effect of pH and buffer concentration on anode biofilms of Thermincola ferriacetica.

    PubMed

    Lusk, Bradley G; Parameswaran, Prathap; Popat, Sudeep C; Rittmann, Bruce E; Torres, Cesar I

    2016-12-01

    We assessed the effects of pH and buffer concentration on current production and growth of biofilms of Thermincola ferriacetica - a thermophilic, Gram-positive, anode-respiring bacterium (ARB) - grown on anodes poised at a potential of -0.06V vs. SHE in microbial electrolysis cells (MECs) at 60°C. T. ferriacetica generated current in the pH range of 5.2 to 8.3 with acetate as the electron donor and 50mM bicarbonate buffer. Maximum current density was reduced by ~80% at pH5.2 and ~14% at 7.0 compared to pH8.3. Increasing bicarbonate buffer concentrations from 10mM to 100mM resulted in an increase in the current density by 40±6%, from 6.8±1.1 to 11.2±2.7Am(-2), supporting that more buffer alleviated pH depression within T. ferriacetica biofilms. Confocal laser scanning microscopy (CLSM) images indicated that higher bicarbonate buffer concentrations resulted in larger live biofilm thicknesses: from 68±20μm at 10mM bicarbonate to >150μm at 100mM, supporting that buffer availability was a strong influence on biofilm thickness. In comparison to mesophilic Geobacter sulfurreducens biofilms, the faster transport rates at higher temperature and the ability to grow at relatively lower pH allowed T. ferriacetica to produce higher current densities with lower buffer concentrations.

  2. The effect of pH and buffer concentration on anode biofilms of Thermincola ferriacetica.

    PubMed

    Lusk, Bradley G; Parameswaran, Prathap; Popat, Sudeep C; Rittmann, Bruce E; Torres, Cesar I

    2016-12-01

    We assessed the effects of pH and buffer concentration on current production and growth of biofilms of Thermincola ferriacetica - a thermophilic, Gram-positive, anode-respiring bacterium (ARB) - grown on anodes poised at a potential of -0.06V vs. SHE in microbial electrolysis cells (MECs) at 60°C. T. ferriacetica generated current in the pH range of 5.2 to 8.3 with acetate as the electron donor and 50mM bicarbonate buffer. Maximum current density was reduced by ~80% at pH5.2 and ~14% at 7.0 compared to pH8.3. Increasing bicarbonate buffer concentrations from 10mM to 100mM resulted in an increase in the current density by 40±6%, from 6.8±1.1 to 11.2±2.7Am(-2), supporting that more buffer alleviated pH depression within T. ferriacetica biofilms. Confocal laser scanning microscopy (CLSM) images indicated that higher bicarbonate buffer concentrations resulted in larger live biofilm thicknesses: from 68±20μm at 10mM bicarbonate to >150μm at 100mM, supporting that buffer availability was a strong influence on biofilm thickness. In comparison to mesophilic Geobacter sulfurreducens biofilms, the faster transport rates at higher temperature and the ability to grow at relatively lower pH allowed T. ferriacetica to produce higher current densities with lower buffer concentrations. PMID:27450427

  3. 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

  4. Macroreticulate buffers: a novel approach to pH control in living systems.

    PubMed

    Righetti, P G; Chiari, M; Crippa, L

    1991-02-01

    It is possible to control the pH of growing living systems in vitro by adding, to the growth media, macroreticulate buffers, i.e. amphoteric resins made with buffering and titrant groups simultaneously affixed to the matrix. Such beads possess a very precise isoelectric point (pI) and are able to maintain the solutions' pH close to their pI values for extended growth periods. These pearls are made of a neutral polyacrylamide backbone containing up to 200 mM grafted weak acrylamido acids and bases. It is possible to produce such buffers with any desired pH value in the pH 2.5-11 scale. An example is given of conditioning the pH of endive plants grown hydroponically. PMID:1366985

  5. Heterogeneous Distribution of Microbial Activity in Methanogenic Aggregates: pH and Glucose Microprofiles

    PubMed Central

    Lens, Piet N. L.; De Beer, Dirk; Cronenberg, Carel C. H.; Houwen, Frans P.; Ottengraf, Simon P. P.; Verstraete, Willy H.

    1993-01-01

    Methanogenic aggregates, harvested from an upflow anaerobic sludge blanket reactor treating potato starch wastewater, were acclimatized to either glucose or a mixture of sugars and organic nitrogen compounds (i.e., diluted molasses). Both types of granules exhibited internal pH and substrate concentration gradients in mineral medium (pH 7.0, 30°C) as was measured with microelectrodes. Glucose-acclimatized granules suspended in a mineral medium lacking glucose exhibited a distinct internal pH decrease of about 1 U within the granule, suggesting strong metabolism by the acidogenic bacteria. Molasses-acclimatized and aged granules suspended in mineral medium did not exhibit such a pH decrease, suggesting the importance of the metabolic state of these acidogens. The pH gradient did not occur in deactivated granules and was not observable in strongly buffered media (mineral medium containing 33 mM phosphate or reactor liquid). When glucose (0.5 to 5.0 mM) was added to the mineral medium, granules exhibited a convex pH profile. Glucose consumption was located exclusively in the outer 200 to 300 μm of the aggregates (mean diameter = 1.5 mm). The addition of 20 mM 2-bromoethanesulfonic acid to the mineral medium indicated that the higher pH levels in the centre of the granule appeared to be related to the activity of methanogens. It is suggested that acidogenic activity occurs predominantly in the outer 200 to 300 μm of the aggregate and methanogenic activity occurs predominantly in the center of the investigated granules. Images PMID:16349091

  6. 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

  7. Mechanisms of microenvironmental pH regulation in the cuticle of Ascaris suum.

    PubMed

    Sims, S M; Magas, L T; Barsuhn, C L; Ho, N F; Geary, T G; Thompson, D P

    1992-07-01

    The excretion kinetics of various organic acids by Ascaris suum were quantified to determine if the excretion of these metabolic end-products could generate and maintain a microclimate pH within the aqueous compartment of the cuticle. Ligated and nonligated A. suum were incubated in media buffered with 0.25 or 2.5 mM Hepes (initial pH 7.5) or 0.5 or 5 mM glycine (initial pH 3.25). The concentration of organic acids and the pH of the media were followed for 24 h. Several volatile fatty acids, including acetic, 2-methylbutyric, 2-methylvaleric, n-valeric, and n-butyric, were excreted at relatively high rates. Propionic, n-caproic, 2-methylcaproic, tiglic acid, and the non-volatile organic acids, lactic and succinic, were excreted more slowly. The organic acids were excreted at a constant rate and in apparently fixed molar concentration ratios. The accumulation of organic acids was associated with changes in pH of the medium until a limiting constant pH, in the vicinity of the pKa of the volatile fatty acids, was reached. The rate of organic acid excretion was not affected by initial medium pH, buffer capacity, or parasite ligation. The rate of pH change induced by the excretion of organic acids was also insensitive to whether ligated or nonligated A. suum were used, but was dependent on the initial buffer capacity of the medium. These results suggest that A. suum excrete the end-products of carbohydrate metabolism across the cuticle. The presence of organic acids in the aqueous pores of the cuticle creates and maintains a microclimate pH of about 5.0 +/- 0.3. This pH will influence the transport properties of weak acids and bases and should be considered in the design of delivery systems for anthelmintics. PMID:1501633

  8. 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.

  9. 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

  10. Variability of repeated coronary artery calcium measurements by 1.25-mm- and 2.5-mm-thickness images on prospective electrocardiograph-triggered 64-slice CT.

    PubMed

    Horiguchi, Jun; Matsuura, Noriaki; Yamamoto, Hideya; Hirai, Nobuhiko; Kiguchi, Masao; Fujioka, Chikako; Kitagawa, Toshiro; Kohno, Nobuoki; Ito, Katsuhide

    2008-02-01

    High reproducibility on coronary artery calcium scoring is a key requirement in monitoring the progression of coronary atherosclerosis. The purpose of this prospective study is to assess the reproducibility of 1.25-mm- and 2.5-mm-thickness images on prospective electrocardiograph-triggered 64-slice CT with respect to 2.5-mm-thickness images on spiral overlapping reconstruction. One hundred patients suspected of coronary artery disease were scanned twice repeatedly, both on prospective electrocardiograph-triggered step-and-shoot and retrospective electrocardiograph-gated spiral scans. Using 1.25-mm-thickness collimation, 1.25-mm- and 2.5-mm-thickness image sets on prospective scans and 2.5-mm-thickness image sets with 1.25-mm increment (overlapping) on retrospective scans were obtained. Coronary artery calcium scores, interscan variability and interobserver variability were evaluated. The mean interscan variability in coronary artery calcium measurement on 1.25-mm prospective/2.5-mm prospective/2.5-mm overlapping retrospective scans were Agatston: 10%/18%/12%, volume: 10%/12%/10% and mass: 8%/13%/11% for observer 1 and Agatston: 8%/14%/10%, volume: 7%/9%/10% and mass: 7%/10%/9% for observer 2, respectively. The mean interobserver variability was 5% to 14%. In conclusion, prospective electrocardiograph-triggered 64-slice CT using the 1.25-mm prospective scan shows the lowest variability. The 2.5-mm prospective scan on volume or mass scoring shows variability of around 10%, comparable to 2.5-mm-thickness spiral overlapping reconstruction images.

  11. pH titrations of molluscan paramyosin at two different ionic strengths.

    PubMed

    Cooley, L B; Krause, S

    1980-11-01

    Paramyosin extracted from the adductor muscle of Mercenaria mercenaria, the chowder clam, was titrated both in 0.3 M KCl and in 1 mM KCl. Both the presumed native form of the molecule, acid-R-paramyosin, and a slightly degraded form, beta-paramyosin, were studied. Titrations of both types of paramyosin were similar in 1 mM k+, except that the native paramyosin is more highly charged at pH 3.2 than beta-paramyosin, as postulated previously (DeLaney and Krause, 1976, Macromolecules, 9:455), and that more groups titrate on the native molecule than on beta-paramyosin, both between pH 3.2 and 3.3 and between pH 3.2 and 10. Titrations in 0.30 M KCl, unlike those in 1 mM K, depended on starting pH; long term exposure to alkali solutions during dialysis, previously shown to cause partial dephosphorylation of paramyosin (Cooley et al., 1979, J. Biol. Chem., 254:2195), apparently also leads to a change in intermolecular interactions sufficient to cause changes in the titration curves in 0.30 M KCl but not in 1 mM K+.

  12. pH titrations of molluscan paramyosin at two different ionic strengths.

    PubMed Central

    Cooley, L B; Krause, S

    1980-01-01

    Paramyosin extracted from the adductor muscle of Mercenaria mercenaria, the chowder clam, was titrated both in 0.3 M KCl and in 1 mM KCl. Both the presumed native form of the molecule, acid-R-paramyosin, and a slightly degraded form, beta-paramyosin, were studied. Titrations of both types of paramyosin were similar in 1 mM k+, except that the native paramyosin is more highly charged at pH 3.2 than beta-paramyosin, as postulated previously (DeLaney and Krause, 1976, Macromolecules, 9:455), and that more groups titrate on the native molecule than on beta-paramyosin, both between pH 3.2 and 3.3 and between pH 3.2 and 10. Titrations in 0.30 M KCl, unlike those in 1 mM K, depended on starting pH; long term exposure to alkali solutions during dialysis, previously shown to cause partial dephosphorylation of paramyosin (Cooley et al., 1979, J. Biol. Chem., 254:2195), apparently also leads to a change in intermolecular interactions sufficient to cause changes in the titration curves in 0.30 M KCl but not in 1 mM K+. PMID:7260299

  13. Preparation of acidic and alkaline macrocapsules for pH control.

    PubMed

    Flora, Joseph R V; Baker, Benjamin; Wybenga, Daniel; Zhu, Huiying; Aelion, C Marjorie

    2008-01-01

    A series of experiments was performed to prepare acidic macroencapsulated buffers composed of 20% Ca(H2PO4)(2) and 80% Eudragit S 100 polymer and alkaline macrocapsules composed of 65% K2HPO4 and 35% Eudragit E PO polymer (the powdered form of Eudragit E 100). Eudragit S 100 was shown to be soluble at a pH greater than 7.0, while Eudragit E 100 was soluble at a pH less than 7.0. Both polymers did not impart significant biochemical oxygen demand. The Eudragit E PO polymer solution showed low toxicity (EC50=91%) based on the Microtox Acute Toxicity Test compared to the 0.1mM background phosphate buffer solution (EC50=100%) while the Eudragit S 100 polymer solution showed higher toxicity (EC50=53%). Batch tests showed that the acidic macrocapsules reduced the pH of a 0.1mM phosphate solution from 11 to neutral, while the alkaline macrocapsules increased the pH of a 0.1mM phosphate solution from 3 to neutral. The macrocapsules could potentially be used as an in situ proportional pH controller for groundwater remediation.

  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. Erroneous gender differences in axillary skin surface/sweat pH.

    PubMed

    Burry, J S; Coulson, H F; Esser, I; Marti, V; Melling, S J; Rawlings, A V; Roberts, G; Mills, A K

    2001-04-01

    Assessing accurately the pH of axillary eccrine sweat is of vital importance in the antiperspirant industry. Eccrine sweat pH is a critical parameter in determining the effectiveness of antiperspirants; antiperspirant salts dissolve in sweat and diffuse into the sweat glands, where the resultant acidic solution hydrolyses in more alkaline sweat forming an amorphous metal hydroxide gel, thereby restricting the flow of eccrine sweat. Comparison of the skin surface and sweat pH of males and females reported in the literature shows that, although consistent male/female differences have been observed on the forearm, determination of significant gender-based pH differences across other sites are less conclusive. Studies on the back and infra-mammary regions exhibited significant gender differences in skin surface pH, whereas those on the forehead, cheek, neck and inguinal area showed no such difference. With regard to the axilla specifically, four studies have been reported, three showing no significant difference in axillary skin surface pH and one indicating that females have an eccrine sweat pH of 7 and males have a sweat pH of 5.6. This paper describes a series of carefully controlled studies aimed at assessing potential gender differences in eccrine sweat and skin surface pH following exposure to a variety of temperature, humidity and time conditions. The results highlight the importance of controlling precisely the time of investigation, site of measurement and, most importantly, the necessity to pre-equilibrate samples in 40 mmHg carbon dioxide (equivalent to arterial CO(2) tension (pCO2)) before determining sweat pH. When these parameters are controlled no gender differences in axillary sweat or skin surface pH are observed. Large differences in eccrine sweat and skin surface pH are found, however, between the vault (hairy region) and fossa (non-hairy region) of the axilla. PMID:18498454

  16. Assessing the performance of MM/PBSA and MM/GBSA methods. 3. The impact of force fields and ligand charge models.

    PubMed

    Xu, Lei; Sun, Huiyong; Li, Youyong; Wang, Junmei; Hou, Tingjun

    2013-07-18

    Here, we systematically investigated how the force fields and the partial charge models for ligands affect the ranking performance of the binding free energies predicted by the Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA) and Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) approaches. A total of 46 small molecules targeted to five different protein receptors were employed to test the following issues: (1) the impact of five AMBER force fields (ff99, ff99SB, ff99SB-ILDN, ff03, and ff12SB) on the performance of MM/GBSA, (2) the influence of the time scale of molecular dynamics (MD) simulations on the performance of MM/GBSA with different force fields, (3) the impact of five AMBER force fields on the performance of MM/PBSA, and (4) the impact of four different charge models (RESP, ESP, AM1-BCC, and Gasteiger) for small molecules on the performance of MM/PBSA or MM/GBSA. Based on our simulation results, the following important conclusions can be obtained: (1) for short time-scale MD simulations (1 ns or less), the ff03 force field gives the best predictions by both MM/GBSA and MM/PBSA; (2) for middle time-scale MD simulations (2-4 ns), MM/GBSA based on the ff99 force field yields the best predictions, while MM/PBSA based on the ff99SB force field does the best; however, longer MD simulations, for example, 5 ns or more, may not be quite necessary; (3) for most cases, MM/PBSA with the Tan's parameters shows better ranking capability than MM/GBSA (GB(OBC1)); (4) the RESP charges show the best performance for both MM/PBSA and MM/GBSA, and the AM1-BCC and ESP charges can also give fairly satisfactory predictions. Our results provide useful guidance for the practical applications of the MM/GBSA and MM/PBSA approaches.

  17. 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.

  18. 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

  19. 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.

  20. Ion-selective electrode for transmembrane pH difference measurements.

    PubMed

    Katsu, T; Nakagawa, H; Kanamori, T; Kamo, N; Tsuchiya, T

    2001-04-15

    A triethylammonium-sensitive electrode was constructed using sodium tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate as an ion-exchanger and benzyl 2-nitrophenyl ether as a solvent mediator in a poly(vinylchloride) membrane matrix and was used to determine the pH difference across a cell membrane. The method is based on monitoring of the pH gradient-induced uptake of triethylammonium in situ. The triethylammonium electrode exhibited a near-Nernstian response to triethylammonium in the concentration range of 5 x 10(-6)-1 x 10(-2) M with a slope of 58.5 mV per concentration decade in a buffer solution composed of 150 mM NaCl and 10 mM NaH2PO4/Na2HPO4 (pH 7.5). The limit of detection was 1 microM. In experiments using liposomes, the uptake of triethylammonium into liposomes was quantitatively induced according to the pH difference across the liposomal membrane. The transmembrane pH differences in Escherichia coli cells and the light-induced pH differences across the envelope vesicles of Halobacterium halobium were successfully determined by the present method.

  1. 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

  2. Online preconcentration of arsenic compounds by dynamic pH junction-capillary electrophoresis.

    PubMed

    Jaafar, Jafariah; Irwan, Zildawarni; Ahamad, Rahmalan; Terabe, Shigeru; Ikegami, Tohru; Tanaka, Nobuo

    2007-02-01

    An online preconcentration technique by dynamic pH junction was studied to improve the detection limit for anionic arsenic compounds by CE. The main target compound is roxarsone, or 3-nitro-4-hydroxyphenylarsonic acid, which is being used as an animal feed additive. The other inorganic and organoarsenic compounds studied are the possible biotransformation products of roxarsone. The arsenic species were separated by a dynamic pH junction in a fused-silica capillary using 15 mM phosphate buffer (pH 10.6) as the BGE and 15 mM acetic acid as the sample matrix. CE with UV detection was monitored at a wavelength of 192 nm. The influence of buffer pH and concentration on dynamic pH junction were investigated. The arsenic species focusing resulted in LOD improvement by a factor of 100-800. The combined use of C18 and anion exchange SPE and dynamic pH junction to CE analysis of chicken litter and soils helps to increase the detection sensitivity. Recoveries of spiked samples ranged between 70 and 72%.

  3. Control of protozoa contamination and lipid accumulation in Neochloris oleoabundans culture: Effects of pH and dissolved inorganic carbon.

    PubMed

    Peng, Licheng; Lan, Christopher Q; Zhang, Zisheng; Sarch, Cody; Laporte, Matt

    2015-12-01

    Combined effects of pH (i.e., 7.5, 8.5, and 9.5) and bicarbonate (i.e., 0, 80 and 160mM NaHCO3) on lipid accumulation and on biological contaminant viability in a protozoa-contaminated culture of the freshwater microalga Neochloris oleoabundans were studied. Cultures grown in the media containing 160mM NaHCO3 at pH 9.5 obtained the highest biomass concentration (DCWmax=1.32g/L), lipid content (LC=327mg/g), which corresponded to a lipid productivity of 56mg/(L·d), and the culture was protozoa free one day after inoculation. Other cultures, 160mM NaHCO3 at pH 8.5 (DCWmax=1.32g/L, LC=223mg/g), and 80mM NaHCO3 at pH 9.5 (DCWmax=1.25g/L, LC=264mg/g) could delay protozoan growth, but not inhibit it completely. These results suggest 160mM NaHCO3 or slightly above at pH levels of 8.5-9.5 may be used in outdoor cultivation processes of freshwater N. oleoabundans to control protozoa contamination while maintain a high lipid content.

  4. 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

  5. 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

  6. Disruption of bovine oocytes and preimplantation embryos by urea and acidic pH.

    PubMed

    Ocon, O M; Hansen, P J

    2003-04-01

    Feeding cattle diets high in degradable crude protein (CP) or in excess of requirements can reduce fertility and lower uterine pH. Objectives were to determine direct effects of urea and acidic pH during oocyte maturation and embryonic development. For experiment 1, oocytes were matured in medium containing 0, 5, 7.5, or 10 mM urea (0, 14, 21, or 28 mg/dl urea nitrogen, respectively). Cleavage rate was not reduced by any concentration of urea. However, the proportion of oocytes developing to the blastocyst stage at d 8 after insemination was reduced by 7.5 mM urea. In addition, the proportion of cleaved oocytes becoming blastocysts was decreased by 5 and 7.5 mM urea. For experiment 2, putative zygotes were collected -9 h after insemination and cultured in modified Potassium Simplex Optimized Medium (KSOM). Urea did not reduce the proportion of oocytes developing to the blastocyst stage, although 10 mM urea reduced cleavage rate slightly. For experiment 3, dimethadione (DMD), a weak nonmetabolizable acid, was used to decrease culture medium pH. Putative zygotes were cultured in modified KSOM containing 0, 10, 15, or 20 mM DMD for 8 d. DMD reduced cleavage rate at 15 and 20 mM and development to the blastocyst stage at all concentrations. Results support the idea that feeding diets rich in highly degradable CP compromises fertility through direct actions of urea on the oocyte and through diet-induced alterations in uterine pH.

  7. Stimulus-secretion coupling in beta-cells: modulation by pH.

    PubMed

    Pace, C S; Tarvin, J T; Smith, J S

    1983-01-01

    We have examined the influence of changes in pH on the oscillatory pattern of electrical activity (EA) in the beta-cell by altering medium pH (pHo) and using permeable weak buffers to alter intracellular pH (pHi). A decrease in pH in the presence of glucose elicited depolarization to the active phase and constant spike activity, whereas an increase in pH elicited a decrease in spike activity or silent hyperpolarization. On inhibition of HCO3:Cl antiport by addition of DIDS (4,4'-diisothiocyano-2,2'-stilbene disulfonic acid), probenecid, or withdrawal of medium HCO-3, there was an increase in the duration of the active phase. A similar result was obtained on the inhibition of Na:H antiport by the addition of amiloride or the reduction of medium [Na+]. The influence of H+ and glucose has been proposed to decrease K+ permeability (PK). However, the influence of pH on 86Rb+ efflux was most effective at subthreshold or 4.2 mM glucose; only a moderate decrease in PK occurred at 8.3 mM glucose, and no effect was obtained at 16.7 mM glucose. Alteration of pHi, and not pHo, induces similar effects on glucose-induced electrical and secretory events. There is a clear dissociation between the influence of inhibitors of the Na:H and HCO3:Cl antiporters on the electrical and secretory events. DIDS and amiloride increased glucose-induced EA, but markedly inhibited the secretory response to glucose. It is evident that pH modulates the electrical events and cationic fluxes and ultimately influences the transduction of information to the mechanisms controlling the secretory process in the beta-cell. PMID:6295181

  8. 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.

  9. 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.

  10. Enzyme biosensor for urea based on a novel pH bulk optode membrane.

    PubMed

    Koncki, R; Mohr, G J; Wolfbeis, O S

    1995-01-01

    A new, absorbance-based enzymatic biosensor membrane for determination of urea is described. A lipophilic, fully LED- and diode laser-compatible pH sensitive dye was incorporated into a plasticized, carboxylated poly(vinyl chloride) membrane and served as the optical transducer of the sensor. Urease was covalently linked to the surface of the pH bulk optode membrane to form a very thin cover. The resulting biosensor membrane allows rapid determination of urea over the 0.3 to 100 mM range. The reproducibility, stability, and effects of pH and buffer concentration on the response of sensor are reported. The preparation of the pH transducer and the immobilization of the enzyme are simple and may easily be adopted to other biosensor types.

  11. pH wave-front propagation in the urea-urease reaction.

    PubMed

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

    2012-08-01

    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.

  12. 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 ...

  13. 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…

  14. 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…

  15. 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…

  16. Response to the "Responsive PhD"

    ERIC Educational Resources Information Center

    Huyssen, David

    2007-01-01

    In June 2005, 50 graduate school deans gathered at Princeton to address the fact that the number of new PhDs conferred each year far exceeds the number of tenure-track academic jobs on offer. Under the auspices of the Woodrow Wilson National Fellowship Foundation's Responsive PhD Project, these deans spoke passionately about how American…

  17. 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…

  18. 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

  19. Colorimetric determination of pH

    SciTech Connect

    Baumann, E.W.; Buchanan, B.R.

    1991-12-31

    There is a need for a simple, rapid, reliable means for determining pH values of concentrated, high salt solutions without reliance on human eye and ambient light. The method comprises the steps of preparing a set of reference solutions, measuring the light absorption by each reference solution, adding indicator dye to each reference solution, measuring the light absorption by each such reference mixture, comparing the two solutions to determine the dye color at each pH, normalizing the spectra of mixture to the isosbestic point, and matching the color of the pH of the solution to one of the colors of the pHs in the reference solution set. In this way, the pH can be determined to within 0.1 pH unit, a far more precise method than using the human eye.

  20. Intracellular pH modulates quinary structure

    PubMed Central

    Cohen, Rachel D; Guseman, Alex J; Pielak, Gary J

    2015-01-01

    NMR spectroscopy can provide information about proteins in living cells. pH is an important characteristic of the intracellular environment because it modulates key protein properties such as net charge and stability. Here, we show that pH modulates quinary interactions, the weak, ubiquitous interactions between proteins and other cellular macromolecules. We use the K10H variant of the B domain of protein G (GB1, 6.2 kDa) as a pH reporter in Escherichia coli cells. By controlling the intracellular pH, we show that quinary interactions influence the quality of in-cell 15N–1H HSQC NMR spectra. At low pH, the quality is degraded because the increase in attractive interactions between E. coli proteins and GB1 slows GB1 tumbling and broadens its crosspeaks. The results demonstrate the importance of quinary interactions for furthering our understanding of protein chemistry in living cells. PMID:26257390

  1. 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.

  2. 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.

  3. 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

  4. Influence of pH on persulfate oxidation of TCE at ambient temperatures.

    PubMed

    Liang, Chenju; Wang, Zih-Sin; Bruell, Clifford J

    2007-01-01

    In situ chemical oxidation (ISCO) is a technology used for groundwater remediation. This laboratory study investigated the use of the oxidant sodium persulfate for the chemical oxidation of trichloroethylene (TCE) at near ambient temperatures (10, 20 and 30 degrees C) to determine the influence of pH (pH=4, 7 and 9) on the reaction rate (i.e., pseudo-first-order rate constants) over the range of temperatures utilized. TCE solutions (60 mg l(-1); 0.46 mM) were prepared in phosphate buffered RO water and a fixed persulfate/TCE molar ratio of 50/1 was employed in all tests. Half-lives of TCE degradation at 10, 20 and 30 degrees C (pH 7) were 115.5, 35.0 and 5.5h, respectively. Maximum TCE degradation occurred at pH 7. Lowering system pH resulted in a greater decrease in TCE degradation rates than increasing system pH. Radical scavenging tests used to identify predominant radical species suggested that the sulfate radical (SO(4)(.-)) predominates under acidic conditions and the hydroxyl radical (.OH) predominates under basic conditions. In a side by side comparison of TCE degradation in a groundwater vs. unbuffered RO water it was demonstrated that when the system pH is buffered to near neutral pH conditions due to the presence of natural occurring groundwater constituents that the TCE degradation rate is higher than in unbuffered RO water where the system pH dropped from 5.9 to 2.8. The results of this study suggest that in a field application of ISCO, pH should be monitored and adjusted to near neutral if necessary.

  5. 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%.

  6. Effects of pH on the ability of flavonoids to act as Pickering emulsion stabilizers.

    PubMed

    Luo, Zijun; Murray, Brent S; Ross, Anne-Lise; Povey, Malcolm J W; Morgan, Michael R A; Day, Andrea J

    2012-04-01

    The flavonoids tiliroside, rutin and naringin have been investigated as stabilizers of Pickering oil-in-water (O/W) emulsions. The mean droplet size of tetradecane emulsions was considerably smaller at higher pH, especially for rutin. The solubility of flavonoids in the aqueous phase was 4-6 times higher at pH 8 compared to pH 2 for tiliroside and rutin, although all absolute solubilities remained low (<1 mM). This agreed with a slight increase in surface activity of tiliroside and rutin at the O-W interface at pH 8 compared to pH 2. However, improved emulsion stabilization at higher pH is better explained by the significant increase in ζ-potential of the flavonoid particles to more negative values at pH 8, which will improve particle dispersion and increase the charge on the droplets stabilized by them. A buckwheat tea extract, rich in rutin, was also shown to be an effective stabilizer of sunflower O/W emulsions.

  7. Changes of the solution pH due to exposure by high-voltage electric pulses.

    PubMed

    Saulis, Gintautas; Lape, Remigijus; Praneviciūte, Rita; Mickevicius, Donatas

    2005-09-01

    The change of the pH of a NaCl solution (139-149 mM NaCl) buffered with 5-15 mM sodium phosphates (pH 7.4) during electromanipulation was studied. It has been determined that an increase in the pH value of electroporation solution of a whole chamber volume, caused by the application of electric field pulses, commonly used in cell electromanipulation procedures, can exceed 1-2 pH units. Several materials for the cathode were tested. In all cases a stainless steel anode was utilized. The aluminum cathode gave a two-fold greater DeltapH in comparison with platinum, copper or stainless steel cathodes. In addition, a substantial release of aluminum (up to 1 mg/l) from the cathode was observed. It has also been found that the shift in pH depended on the medium conductivity: DeltapH of the solution, in which sucrose was substituted for NaCl, was about 5 times less. On the basis of the results obtained here, to avoid the plausible undesirable consequences of the cathodic electrolysis processes, in particular under the conditions of strong electric treatment, it could be recommended that chambers with aluminum electrodes not be utilized and one should use strongly buffered solutions of low conductivity and alternating current (sine or square wave) bipolar electric pulses. PMID:15967404

  8. Submillimeter Array Observations Toward the Massive Star-forming Core MM1 of W75N

    NASA Astrophysics Data System (ADS)

    Minh, Y. C.; Su, Y.-N.; Chen, H.-R.; Liu, S.-Y.; Yan, C.-H.; Kim, S.-J.

    2010-11-01

    The massive star-forming core MM1 of W75N was observed using the Submillimeter Array with ~1'' and 2'' spatial resolutions at 217 and 347 GHz, respectively. From the 217 GHz continuum we found that the MM1 core consists of two sources, separated by about 1'': MM1a (~0.6 M sun) and MM1b (~1.4 M sun), located near the radio continuum sources VLA 2/VLA 3 and VLA 1, respectively. Within MM1b, two gas clumps were found to be expanding away from VLA 1 at about ±3 km s-1, as a result of the most recent star formation activity in the region. Observed molecular lines show emission peaks at two positions, MM1a and MM1b: sulfur-bearing species have emission peaks toward MM1a, but methanol and saturated species at MM1b. We identified high-temperature (~200 K) gas toward MM1a and the hot core in MM1b. This segregation may result from the evolution of the massive star-forming core. In the very early phase of star formation, the hot core is seen through the evaporation of dust ice-mantle species. As the mantle species are consumed via evaporation the high-temperature gas species (such as the sulfur-bearing molecules) become bright. The SiO molecule is unique in having an emission peak exactly at the VLA 2 position, probably tracing a shock powered by VLA 2. The observed sulfur-bearing species show similar abundances both in MM1a and MM1b, whereas the methanol and saturated species show significant abundance enhancement toward MM1b, by about an order of magnitude, compared to MM1a.

  9. [Diagnostic value of lochial pH, pCO2,and pO2 in puerperal endometritis].

    PubMed

    Nikonov, A P; Burlev, V A; Ankirskaia, A S; Sergeev, M V; Lutfullaeva, N A

    1991-06-01

    A new method has been developed for rapid diagnosis of puerperial endometritis, based on measurements of lochial pH, pCO2, and pO2. Endometritis development is associated with acidosis in the uterine cavity (pH 6.8-7.2), elevation of pCO2 to make 40-70 mm Hg, and reduction of pO2 to make 40-80 mm Hg. The degree of these shifts is in direct relationship with the inflammatory process severity. The method is simple, almost noninvasive, and quite reliable. PMID:1951953

  10. Effects of Atmospheric Air Plasma Irradiation on pH of Water

    NASA Astrophysics Data System (ADS)

    Sarinont, Thapanut; Koga, Kazunori; Kitazaki, Satoshi; Uchida, Giichirou; Hayashi, Nobuya; Shiratani, Masaharu

    We have studied the effects of atmospheric air plasma irradiation to water using a scalable dielectric barrier discharge device. Measurements of the pH of water treated by the plasmas have shown the pH decreases due to peroxide molecules generated by plasma irradiation and depends on material of water container. We also found this plasma treated water has little effect on the growth enhancement on Radish sprouts compare with plasma irradiation on dry seeds and the plasma irradiation can affect them through the water buffer of 0.2 mm in thickness.

  11. Simultaneous water desalination and electricity generation in a microbial desalination cell with electrolyte recirculation for pH control.

    PubMed

    Qu, Youpeng; Feng, Yujie; Wang, Xin; Liu, Jia; Lv, Jiangwei; He, Weihua; Logan, Bruce E

    2012-02-01

    A recirculation microbial desalination cell (rMDC) was designed and operated to allow recirculation of solutions between the anode and cathode chambers. This recirculation avoided pH imbalances that could inhibit bacterial metabolism. The maximum power density was 931±29mW/m(2) with a 50mM phosphate buffer solution (PBS) and 776±30mW/m(2) with 25mM PBS. These power densities were higher than those obtained without recirculation of 698±10mW/m(2) (50mM PBS) and 508±11mW/m(2) (25mM PBS). The salt solution (20g/L NaCl) was reduced in salinity by 34±1% (50mM) and 37±2% (25mM) with recirculation (rMDC), and by 39±1% (50mM) and 25±3% (25mM) without recirculation (MDC). These results show that electrolyte recirculation using an rMDC is an effective method to increase power and achieve efficient desalination by eliminating pH imbalances.

  12. Fluorescence ratio imaging of interstitial pH in solid tumours: effect of glucose on spatial and temporal gradients.

    PubMed Central

    Dellian, M.; Helmlinger, G.; Yuan, F.; Jain, R. K.

    1996-01-01

    Tumour pH plays a significant role in cancer treatment. However, because of the limitations of the current measurement techniques, spatially and temporally resolved pH data, obtained non-invasively in solid tumours, are not available. Fluorescence ratio imaging microscopy (FRIM) has been used previously for noninvasive, dynamic evaluation of pH in neoplastic tissue in vivo (Martin GR, Jain RK 1994, Cancer Res., 54, 5670-5674). However, owing to problems associated with quantitative fluorescence in thick biological tissues, these studies were limited to thin (50 microns) tumours. We, therefore, adapted the FRIM technique for pH determination in thick (approximately 2 mm) solid tumours in vivo using a pinhole illumination-optical sectioning (PIOS) method. Results show that (1) steep interstitial pH gradients (5 microns resolution), with different spatial patterns, exist between tumour blood vessels; (2) pH decreased by an average of 0.10 pH units over a distance of 40 microns away from the blood vessel wall, and by 0.33 pH units over a 70 microns distance; (3) the maximum pH drop, defined as the pH difference between the intervessel midpoint and the vessel wall, was positively correlated with the intervessel distance; (4) 45 min following a systemic glucose injection (6 g kg-1 i.v), interstitial pH gradients were shifted to lower pH values by an average of 0.15 pH units, while the spatial gradient (slope) was maintained, when compared with preglucose values. This pH decrease was not accompanied by significant changes in local blood flow. pH gradients returned to near-baseline values 90 min after glucose injection; (5) interstitial tumour pH before hyperglycaemia and the glucose-induced pH drop strongly depended on the local vessel density; and (6) sodium bicarbonate treatment, either acute (1 M, 0.119 ml h-1 for 3 h i.v.) or chronic (1% in drinking water for 8 days), did not significantly change interstitial tumour pH. Modified FRIM may be combined with other optical

  13. 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.

  14. Development and application of specially-focused ultrasonic transducers to location and sizing of defects in 75 mm- to 127 mm-thick austenitic stainless steel weld metals

    SciTech Connect

    Dalder, E.N.C.; Benson, S.; McKinley, B.J.; Carodiskey, T.

    1992-08-01

    Special UT transducer parts, capable of focusing incident signals within a 25 mm {times} 25 mm {times} 25 mm volume in an austenitic stainless weld metal at depths that varied from 25 mm to 127 mm, were developed and demonstrated to be capable of detecting a defect with cross section equivalent to that of a 4.76 mm-dia flat-bottom hole. Defect length sizing could be accomplished to {plus_minus}50% for 100% of the time and to {plus_minus}25% on selected defect types as follows: porosity groups, 100%; cracks, 67%; combined slag and porosity, 60%; and linear slag indications, 59%. Extensive linear elastic-fracture-mechanics analyses were performed to establish allowable defect sizes at functions of stress, based on a cyclic-life criterion of 10{sup 3} full power cycles of the MFTF-B magnet system. These defect sizes were used to determine which UT indicating were to be removed and repaired and which were to be retained and their recorded sizes and locations.

  15. 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

  16. pH- and concentration-programmable electrodialytic buffer generator.

    PubMed

    Chen, Yongjing; Edwards, Brian L; Dasgupta, Purnendu K; Srinivasan, Kannan

    2012-01-01

    We have presented in a companion paper a suppressor-based electrodialytic buffer generator (EBG) that can produce programmable pH gradients. Here we demonstrate a three-electrode EBG. In this three-compartment flow-through device, the central compartment is separated from the outer compartments with a cation-exchange membrane (CEM) and an anion-exchange membrane (AEM), respectively. One platinum electrode is disposed in each compartment. The flows through each compartment are independent. With appropriate solutions in each compartment, independent potentials are applied to the CEM and AEM electrodes with respect to the grounded central electrode. The CEM current and the AEM current can be independently manipulated to generate buffers with variable concentration and pH in the central compartment. Both the CEM and AEM currents can be positive or negative. For the CEM, a positive current (i(cat)(in)) indicates that cations are coming in from the CEM channel to the center. A negative current (i(cat)(out)) takes cations out of the center to the CEM channel. Similarly for the AEM, currents governing anion transport into the center channel from the AEM channel (AEM electrode negative) or the reverse (AEM electrode positive) are respectively denoted by i(an)(in) or i(an)(out). Most examples herein involve inward ion transport, referred to as the additive mode. Depending on whether i(cat)(in) i(an)(in), H(+)/O(2) and OH(-)/H(2) are respectively produced at the central electrode to maintain electroneutrality. Any gas formed is subsequently removed by a gas removal device. The pH of the central channel effluent is related to the ratio of the currents through the two membranes, while the generated concentration is controlled by the absolute value of the currents. The buffer concentration and pH can be varied in a controlled predictable manner. A pH span of 3-12 was attained and a phosphate buffer concentration up to 140 mM was generated. We

  17. Effects of pH and phosphate on CeO2 nanoparticle dissolution.

    PubMed

    Dahle, Jessica T; Livi, Ken; Arai, Yuji

    2015-01-01

    As the result of rapidly grown nanotechnology industries, release of engineered nanoparticles (ENPs) to environment has increased, posing in a serious risk to environmental and human health. To better understand the chemical fate of ENPs in aquatic environments, solubility of CeO2 NPs was investigated using batch dissolution experiments as a function of pH (1.65-12.5), [phosphate] and particle size (33 and 78 nm). It was found that CeO2 dissolution was only significant at pH<5 and inversely proportional to surface area. After 120 h, the release of Ce was ∼3 times greater in large NPs than that in small NPs that is likely contributed by the difference in exchangeable Ce(III) impurity (small: 0.3 mM kg(-1), large: 1.56 mM kg(-1)). When 100 μM of phosphate was added, the dissolution rate of CeO2 NPs was decreased in small NPs by 15% at pH 1.65 and 75% at pH 4.5 and in large NPs by 56% at pH 1.65 and 63% at pH 4.5. The inner-sphere surface complexation of P that is revealed by the zeta potential measurements is effectively suppressing the CeO2 NP dissolution. Predicting the fate and transport of CeO2 NPs in aquatic environment, pH and P ligands might play important roles in controlling the solubility of CeO2 NPs.

  18. 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.

  19. Rainwater ph in the vicinity of hadera power plant, Israel during the winter season of 1981/82

    NASA Astrophysics Data System (ADS)

    Kolton-Shapira, Rivka; Lakritz, Yerucham; Luria, Menachem

    A new method for the continuous pH measurement of rainwater is discussed. Tkis method, applied at a site near a new coal-fired power plant (before its operation), showed a pH variation of 4.3 to 9.2 as compared to 6.5 ± 1.0 observed using conventional methods which measure pH at the end of each rain episode. The alkalinity of top soil in the vicinity, and hence natural aerosols act as a buffer, reducing the acidity of the rain. This buffering effect disappears after 30-40 mm of rainfall.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Effects of pH and elevated glucose levels on the electrochemical behavior of dental implants.

    PubMed

    Tamam, Evsen; Turkyilmaz, Ilser

    2014-04-01

    Implant failure is more likely to occur in persons with medically compromising systemic conditions, such as diabetes related to high blood glucose levels and inflammatory diseases related to pH levels lower than those in healthy people. The aim of this study was to investigate the effects of lower pH level and simulated- hyperglycemia on implant corrosion as these effects are critical to biocompatibility and osseointegration. The electrochemical corrosion properties of titanium implants were studied in four different solutions: Ringer's physiological solution at pH = 7.0 and pH = 5.5 and Ringer's physiological solution containing 15 mM dextrose at pH = 7 and pH = 5.5. Corrosion behaviors of dental implants were determined by cyclic polarization test and electrochemical impedance spectroscopy. Surface alterations were studied using a scanning electron microscope. All test electrolytes led to apparent differences in corrosion behavior of the implants. The implants under conditions of test exhibited statistically significant increases in I(corr) from 0.2372 to 1.007 μAcm(-2), corrosion rates from 1.904 to 8.085 mpy, and a decrease in polarization resistances from 304 to 74 Ω. Implants in dextrose-containing solutions were more prone to corrosion than those in Ringer's solutions alone. Increasing the acidity also yielded greater corrosion rates for the dextrose-containing solutions and the solutions without dextrose.

  8. 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.

  9. Alkalinizing the intralysosomal pH inhibits degranulation of human neutrophils.

    PubMed Central

    Klempner, M S; Styrt, B

    1983-01-01

    Degranulation of lysosomes is one of the consequences of neutrophil activation. Regulatory mechanisms of lysosomal secretion are thought to be localized largely in the plasma membrane and cytosol, with the lysosome playing a passive role in secretion. Recent evidence indicates that the intralysosomal pH is highly acidic (pH congruent to 5.5) and is maintained by active transport of H+. We investigated whether changes in the intralysosomal pH altered the availability of lysosomes for exocytosis. Intralysosomal pH in intact neutrophils was monitored with the weakly basic fluorescent probe, 9-aminoacridine (9AA). The weak bases, methylamine, chloroquine, clindamycin, propanolol, and ammonium chloride (0.1-50 mM), caused an alkalinization of the intralysosomal pH as determined by reversal of quenching of 9AA fluorescence. Similarly, each of the weak bases, including ammonium chloride, methylamine, chloroquine, ethylamine, propylamine, propanolol, clindamycin, and dansylcadaverine, inhibited neutrophil degranulation in response to the calcium ionophore A23187, phorbol myristate acetate, or the chemotactic peptide, formyl-methionine-leucine-phenylalanine plus cytochalasin B. These studies indicate that an acid intralysosomal pH is important to the neutrophil secretory response and suggest that the lysosome may play an active part in control of degranulation. PMID:6415117

  10. Effects of pH and elevated glucose levels on the electrochemical behavior of dental implants.

    PubMed

    Tamam, Evsen; Turkyilmaz, Ilser

    2014-04-01

    Implant failure is more likely to occur in persons with medically compromising systemic conditions, such as diabetes related to high blood glucose levels and inflammatory diseases related to pH levels lower than those in healthy people. The aim of this study was to investigate the effects of lower pH level and simulated- hyperglycemia on implant corrosion as these effects are critical to biocompatibility and osseointegration. The electrochemical corrosion properties of titanium implants were studied in four different solutions: Ringer's physiological solution at pH = 7.0 and pH = 5.5 and Ringer's physiological solution containing 15 mM dextrose at pH = 7 and pH = 5.5. Corrosion behaviors of dental implants were determined by cyclic polarization test and electrochemical impedance spectroscopy. Surface alterations were studied using a scanning electron microscope. All test electrolytes led to apparent differences in corrosion behavior of the implants. The implants under conditions of test exhibited statistically significant increases in I(corr) from 0.2372 to 1.007 μAcm(-2), corrosion rates from 1.904 to 8.085 mpy, and a decrease in polarization resistances from 304 to 74 Ω. Implants in dextrose-containing solutions were more prone to corrosion than those in Ringer's solutions alone. Increasing the acidity also yielded greater corrosion rates for the dextrose-containing solutions and the solutions without dextrose. PMID:24779948

  11. Eukaryotic diversity at pH extremes.

    PubMed

    Amaral-Zettler, Linda A

    2012-01-01

    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.

  12. 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

  13. 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.

  14. 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

  15. Seed coordinates of a new COMS-like 24 mm plaque verified using the FARO Edge.

    PubMed

    McCauley Cutsinger, Sarah E; Furutani, Keith M; Forsman, Renae M; Corner, Stephen M

    2015-11-08

    A 24 mm COMS-like eye plaque was developed to meet the treatment needs of our eye plaque brachytherapy practice. As part of commissioning, it was necessary to determine the new plaque's seed coordinates. The FARO Edge, a commercially available measurement arm, was chosen for this purpose. In order to validate the FARO Edge method, it was first used to measure the seed marker coordinates in the silastic molds for the standard 10, 18, and 20 mm COMS plaques, and the results were compared with the standard published Task Group 129 coordinates by a nonlinear least squares match in MATLAB version R2013a. All measured coordinates were within 0.60 mm, and root mean square deviation was 0.12, 0.23, and 0.35 mm for the 10, 18, and 20 mm molds, respectively. The FARO Edge was then used to measure the seed marker locations in the new 24 mm silastic mold. Those values were compared to the manufacturing specification coordinates and were found to demonstrate good agreement, with a maximum deviation of 0.56mm and a root mean square deviation of 0.37 mm. The FARO Edge is deemed to be a reliable method for determining seed coordinates for COMS silastics, and the seed coordinates for the new 24 mm plaque are presented.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. pH in human tumour xenografts: effect of intravenous administration of glucose.

    PubMed Central

    Volk, T.; Jähde, E.; Fortmeyer, H. P.; Glüsenkamp, K. H.; Rajewsky, M. F.

    1993-01-01

    pH frequency distributions of tumours grown s.c. from 30 human tumour xenograft lines in rnu/rnu rats were analysed with the use of H+ ion-sensitive semi-microelectrodes prior to and following stimulation of tumour cell glycolysis by i.v. infusion of glucose. At normoglycemia, the average pH of the tumours investigated was 6.83 (range, 6.72-7.01; n = 268). Without exception, all xenografts responded to the temporary increase in plasma glucose concentration (PGC) from 6 +/- 1 to 30 +/- 3 mM by an accumulation of acidic metabolites, as indicated by a pH reduction to an average value of 6.43 (range, 6.12-6.78; n = 292). This pH value corresponds to a ten-fold increase in H+ ion activity in tumour tissue as compared to arterial blood. Tumour pH approached minimum values at 2-4 h after the onset of glucose administration and could be maintained at acidic levels for 24 h by controlled glucose infusion. Irrespective of pH variations between tumours grown from individual xenograft lines, there was no major difference in pH response to glucose between the four main histopathological tumour entities investigated, i.e. breast, lung and gastrointestinal carcinomas, and sarcomas. In tumours from several xenograft lines, an increase in blood glucose to only 2.5-times the normal value (14 mM) was sufficient to reduce the mean pH to 6.4. Glucose-induced acidosis was tumour-specific. The pH frequency distributions in liver, kidney and skeletal muscle of tumour-bearing rnu/rnu rats were only marginally sensitive to hyperglycemia (average pH, 6.97 vs normal value of 7.14). Tumour-selective activation of pH-sensitive anti-cancer agents, e.g. alkylating drugs, acid-labile prodrugs or pH-sensitive immunoconjugates may thus be feasible in a wide variety of human cancers. PMID:8353039

  1. Laboratory sand column study of encapsulated buffer release for potential in situ pH control.

    PubMed

    Rust, Christine M; Aelion, C Marjorie; Flora, Joseph R V

    2002-01-01

    Encapsulation technology is being investigated as a method for controlling pH in situ at contaminated groundwater sites where pH may limit remediation of organic contaminants. This study examined the effectiveness of using KH2PO4 buffer encapsulated in a pH-sensitive coating to neutralize pH in laboratory sand columns (1.5-1) under a simulated groundwater flow rate and characterized the pattern of capsule release in the flow-through system. Denitrification was used in the columns to increase the pH of the pore water. Each of three columns was equipped with three miniature mesh wells to allow contact of the buffer with column pore water, but capsules (15 g) were inserted into only one column (amended). The two other columns served as amendment (no buffer) and abiotic (no denitrification) controls. Oxidation-reduction potential, dissolved organic and inorganic carbon, NH4+, NO3- +NO2-, PO(4)3-, and pH were measured in the influent, two side ports, and effluent of the columns over time. Near complete conversion of 80 mg N/1 of nitrate and 152 mg/l of ethanol per day resulted in a mean pH increase from 6.2 to 8.2 in the amendment control column. The amended column maintained the target pH of 7.0 +/- 0.2 for 4 weeks until the capsules began to be depleted, after which time the pH slowly started to increase. The capsules exhibited pulses of buffer release, and were effectively dissolved after 7.5 weeks of operation. Base-neutralizing capacity contributed by the encapsulated buffer over the entire study period, calculated as cation equivalents, was 120 mM compared to 8 mM without buffer. This study demonstrates the potential for this technology to mediate pH changes and provides the framework for future studies in the laboratory and in the field, in which pH is controlled in order to enhance organic contaminant remediation by pH-sensitive systems.

  2. Effect of temperature, pH, and ions on sweet taste.

    PubMed

    Schiffman, S S; Sattely-Miller, E A; Graham, B G; Bennett, J L; Booth, B J; Desai, N; Bishay, I

    2000-02-01

    The purpose of this experiment was to determine the effects of temperature (50 degrees C and 6 degrees C), pH (pH 3.0, 4.0, 5.0, 6. 0, and 7.0) and the addition of monovalent and divalent cations (5 mM Na(+), 5 mM K(+), and 5 mM Ca(2)+ ) on the sweetness intensity ratings of sweeteners ranging widely in chemical structure. A trained panel provided intensity evaluations for prototypical tastes (sweet, bitter, sour, and salty) as well as aromatic and mouth-feel attributes. The following sweeteners were included in this experiment: three sugars (fructose, glucose, sucrose), three terpenoid glycosides (monoammonium glycyrrhizinate, rebaudioside-A, stevioside), two polyhydric alcohols (mannitol, sorbitol), two dipeptide derivatives (alitame, aspartame), two N-sulfonylamides (acesulfame-K, sodium saccharin), one sulfamate (sodium cyclamate), one protein (thaumatin), one dihydrochalcone (neohesperidin dihydrochalcone), and one chlorodeoxysugar (sucralose). Two to five levels of each sweetener reflecting a range of sweetness intensities were tested, using formulae developed by DuBois et al. The main finding from this three-part study was that temperature, pH, and ions had little effect on perceived sweetness intensity. Even when significant differences were found in the temperature study, the effects were very small.

  3. 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.

  4. 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

  5. Immobilized pH gradients (IPG) simulator--an additional step in pH gradient engineering: II. Nonlinear pH gradients.

    PubMed

    Righetti, P G; Tonani, C

    1991-12-01

    While in the companion paper (Tonani, C. & Righetti, P. G., Electrophoresis 1991, 12, 1011-1021) we gave the general outline of our new computer program, immobilized pH gradients (IPG) simulator, able to simulate and optimize linear pH gradients for isoelectric focusing in immobilized pH gradients, in the present report we extend the application of such a program to: (i) convex exponential gradients, (ii) logarithmic and (iii) polynomial gradients. Such gradients are meant to give equal space to protein spots in complex protein mixtures (e.g., cell lysates, biological fluids) and follow the statistical distribution of protein pI values along the pH axis. They will prove of fundamental importance in two-dimensional maps, both because they optimize the spreading of spots in the two-dimensional plane and because of the excellent reproducibility of immobilized pH gradients. The following concave exponential recipes are given: pH 3-8, pH 3-9, pH 3-10, pH 3-11, pH 4-7, pH 4-8, pH 4-9, pH 4-10, pH 4-11, pH 5-8, pH 5-9, and pH 5-10, as well as the most extended pH 2.5-11 interval. Two interesting logarithmic gradients are described: pH 3-6 and pH 3-7 and one sigmoidal (derived with a polynomial of 5th degree): pH 3-11.

  6. pH fluorescent probes: chlorinated fluoresceins.

    PubMed

    Ge, Feng-Yan; Chen, Li-Gong

    2008-01-01

    A series of regiospecific chlorinated fluoresceins have been synthesized by the reaction of the regiospecific chlorinated resorcinols with chlorinated phthalic anhydride. The regioisomers were successfully separated by chromatography. The photophysical properties of the obtained chlorinated fluoresceins were examined and found their absorption and emission maxima at long wavelength with high fluorescence quantum yield. Especially, pH-dependent properties of chlorinated fluoresceins have been studied in detail. These compounds show strongly pH-sensitive range of 3.5-7.0, and have lower pK (a) values than fluorescein. Furthermore, their fluorescent intensity could reach the maximum in the physiological environment of pH range 6.8-7.4. Due to higher fluorescence quantum yield and lower pK (a) values, chlorinated fluoresceins will be expected to be used as excellent pH fluorescent probes for pH measurement of the acidic cell.

  7. Pattern recognition of ocean pH

    NASA Astrophysics Data System (ADS)

    Parker, Albert

    2016-09-01

    The manuscript shows how the few, scattered, latest measurements of ocean pH lacking a proper spatial and time coverage do not permit a meaningful computation of global trends, as the ocean pH is strongly variable in latitude, longitude and depth and very likely is subject to the multi-decadal oscillations that have been identified in the atmospheric and ocean systems. The proposed mathematical model is based on the assumption that the monthly averaged ocean pH may be described by the superposition of a linear trend and inter-annual, decadal and multi-decadal oscillations, with linear and sinusoidal regression coefficients requiring data that are presently unavailable.

  8. 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.

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

    PubMed

    Fernández-Niño, Miguel; Marquina, Maribel; Swinnen, Steve; Rodríguez-Porrata, Boris; Nevoigt, Elke; Ariño, Joaquín

    2015-11-01

    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.

  10. Sensitization of Listeria monocytogenes to Low pH, Organic Acids, and Osmotic Stress by Ethanol

    PubMed Central

    Barker, Clive; Park, Simon F.

    2001-01-01

    The killing of Listeria monocytogenes following exposure to low pH, organic acids, and osmotic stress was enhanced by the addition of 5% (vol/vol) ethanol. At pH 3, for example, the presence of this agent stimulated killing by more than 3 log units in 40 min of exposure. The rate of cell death at pH 3.0 was dependent on the concentration of ethanol. Thus, while the presence 10% (vol/vol) ethanol at pH 3.0 stimulated killing by more than 3 log units in just 5 min, addition of 1.25% (vol/vol) ethanol resulted in less than 1 log unit of killing in 10 min. The ability of 5% (vol/vol) ethanol to stimulate killing at low pH and at elevated osmolarity was also dependent on the amplitude of the imposed stress, and an increase in the pH from 3.0 to 4.0 or a decrease in the sodium chloride concentration from 25 to 2.5% led to a marked reduction in the effectiveness of 5% (vol/vol) ethanol as an augmentative agent. Combinations of organic acids, low pH, and ethanol proved to be particularly effective bactericidal treatments; the most potent combination was pH 3.0, 50 mM formate, and 5 % (vol/vol) ethanol, which resulted in 5 log units of killing in just 4 min. Ethanol-enhanced killing correlated with damage to the bacterial cytoplasmic membrane. PMID:11282610

  11. 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)

  12. The M/M Center: Meeting the Demand for Multicultural, Multilingual Teacher Preparation

    ERIC Educational Resources Information Center

    Wong, Pia Lindquist; Murai, Harold; Berta-Avila, Margarita; William-White, Lisa; Baker, Susan; Arellano, Adele; Echandia, Adriana

    2007-01-01

    The Multilingual/Multicultural Teacher Preparation Center (M/M Center), a teacher preparation program offered by the Bilingual/Multicultural Education Department (BMED) at California State University, Sacramento, is entering its third decade of operation. The M/M Center was established by a group of progressive teacher educators, most with a…

  13. 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…

  14. 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...

  15. 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...

  16. 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…

  17. Ratiometric imaging of pH probes.

    PubMed

    Grillo-Hill, Bree K; Webb, Bradley A; Barber, Diane L

    2014-01-01

    Measurement of intracellular pH can be readily accomplished using tools and methods described in this chapter. We present a discussion of technical considerations of various ratiometric pH-sensitive probes including dyes and genetically encoded sensors. These probes can be used to measure pH across physical scales from macroscopic whole-mount tissues down to organelles and subcellular domains. We describe protocols for loading pH-sensitive probes into single cells or tissues and discuss ratiometric image acquisition and analysis.

  18. 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.

  19. pH regulation in anoxic rice coleoptiles at pH 3.5: biochemical pHstats and net H+ influx in the absence and presence of NO3−

    PubMed Central

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

    2012-01-01

    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 NO3−, which distinguished two processes involved in pH regulation. Net H+ influx (μmol g−1 fresh weight h−1) for coleoptiles with NO3− was ∼1.55 over the first 24 h, being about twice that in the absence of NO3−, but then decreased to 0.5–0.9 as net NO3− uptake declined from ∼1.3 to 0.5, indicating reduced uptake via H+–NO3− symports. NO3− 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 NO3− 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

  20. dMM-PBSA: A New HADDOCK Scoring Function for Protein-Peptide Docking.

    PubMed

    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

  1. 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.

  2. 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

  3. 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

  4. 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

  5. Influence of NaCl, urea, potassium and pH on HSP72 expression in MDCK cells.

    PubMed

    Neuhofer, W; Müller, E; Grünbein, R; Thurau, K; Beck, F X

    1999-12-01

    The renal inner medulla is characterised by elevated extracellular concentrations of NaCl, urea, potassium and hydrogen ions, an environment that may affect cell viability negatively. High amounts of HSP72, a stress protein allowing cells to resist harmful situations, are also observed in this region. The present study examined HSP72 induction by various medullary stress factors, individually or in combination, in MDCK cells, a renal epithelial cell line expressing characteristics of the medullary collecting duct. MDCK cells were incubated for 3 days in media containing elevated concentrations of NaCl, urea, potassium and hydrogen ions individually or in combination. HSP72 mRNA and protein expression were determined by Northern and Western blot analyses, respectively. HSP72 expression was enhanced moderately by addition of 50 mM NaCl to normal medium at pH 7.4 but enhanced strongly when added at pH 6.5. The latter degree of HSP72 induction was comparable to that observed when 150 mM NaCl was added at pH 7.4. In normal medium (pH 7.4) containing 300 mM urea, MDCK HSP72 expression was not different from controls. In contrast, urea-induced HSP72 expression was clearly evident when medium pH was lowered to 6.5. Potassium at 20 or 40 mM induced HSP72 only slightly. These results indicate that expression of HSP72 in renal epithelial cells is regulated synergistically by NaCl, urea and pH. Since HSP72 is only slightly induced by increased potassium, this probably reflects the changes in medium osmolality rather than a specific effect of potassium. The high medullary HSP72 content observed even in diuresis may be due to co-operative effects of medullary solutes on HSP72 expression.

  6. 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

  7. Oxidative dissolution of chromium(III) hydroxide at pH 9, 3, and 2 with product inhibition at pH 2.

    PubMed

    Lee, Giehyeon; Hering, Janet G

    2005-07-01

    Hexavalent chromium, Cr(VI), can be immobilized under neutral to alkaline conditions by reduction to Cr(III); similarly, the mobility of naturally occurring Cr in soils and sediments can be limited by its occurrence in the +III oxidation state. Conversely, the oxidation of Cr(IIi) to Cr(VI) increases both its toxicity and often its mobility. Dissolution of Cr-(OH)3(s) in 0.01 M NaNO3 suspensions was examined in batch experiments in the presence and absence of the strong oxidant sodium hypochlorite (NaOCI). Dissolution of Cr(OH)3(s) (1.0 g/L) was accelerated in the presence of excess strong oxidant (20 mM) at pH 9 by a factor of ca. 200 and to a lesser extent at pH 2 and 3. Linear kinetics of oxidative dissolution was observed at pH 9 and 3. In contrast, the rate of Cr release at pH 2 decreased rapidly with time, and within 2.5 h, the dissolution reaction was completely inhibited. Under oxidizing conditions, Cr released into solution is expected to be present as Cr(VI), which sorbs strongly to Cr(OH)3(s) at low pH. Cr(VI) sorption followed a Langmuir isotherm and reached maximum sorption densities of 308 +/- 8 and 271 +/- 10 micromol/g at pH 3 and 2, respectively. However, sorption of Cr(VI) (putatively formed during oxidative dissolution) cannot explain the observed inhibition of the reaction because (1) sorption occurs at both pH 2 and 3 but inhibition only at pH 2 and (2) preequilibration of Cr(OH)3(s) with Cr(VI) did not affectthe rate of dissolution observed upon the addition of the oxidant. Thus, we hypothesize that the inhibition of (net) oxidative dissolution at pH 2 may be the result of secondary precipitation of a chromic hydroxy chromate phase.

  8. Monitoring fetal pH by telemetry

    NASA Technical Reports Server (NTRS)

    Blum, A.; Donahoe, T.; Jhabvala, M. D.; Ryan, W.

    1980-01-01

    Telemetry unit has been developed for possible use in measuring scalp-tissue pH and heart rate of unborn infant. Unit radius data to receiver as much as 50 ft. away. Application exists during hours just prior to childbirth to give warning of problems that might require cesarean delivery.

  9. 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.

  10. 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…

  11. Development of sulfonamide AKT PH domain inhibitors

    PubMed Central

    Ahad, Ali Md.; Zuohe, Song; Du-Cuny, Lei; Moses, Sylvestor A.; Zhou, Li Li; Zhang, Shuxing; Powis, Garth; Meuillet, Emmanuelle J.; Mash, Eugene A.

    2011-01-01

    Disruption of the phosphatidylinositol 3-kinase/AKT signaling pathway can lead to apoptosis in cancer cells. Previously we identified a lead sulfonamide that selectively bound to the pleckstrin homology (PH) domain of AKT and induced apoptosis when present at low micromolar concentrations. To examine the effects of structural modification, a set of sulfonamides related to the lead compound was designed, synthesized, and tested for binding to the expressed PH domain of AKT using a surface plasmon resonance-based competitive binding assay. Cellular activity was determined by means of an assay for pAKT production and a cell killing assay using BxPC3 cells. The most active compounds in the set are lipophilic and possess an aliphatic chain of the proper length. Results were interpreted with the aid of computational modeling. This paper represents the first structure-activity relationship (SAR) study of a large family of AKT PH domain inhibitors. Information obtained will be used in the design of the next generation of inhibitors of AKT PH domain function. PMID:21353784

  12. 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…

  13. 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…

  14. What My Ph.D. Taught Me

    ERIC Educational Resources Information Center

    Levenstein, Jessica

    2013-01-01

    The author started in the Ph.D. program in comparative literature at Princeton in 1992, a year after she graduated from college. She fell in love with mythology and the classical traditions and find herself teaching literature. In the remainder of her time at Princeton, she precepted for four or five more classes, got the chance to join the…

  15. 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…

  16. 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…

  17. Treatment of Pigmented Basal Cell Carcinoma with 3 mm Surgical Margin in Asians

    PubMed Central

    Cheng, Yu-Wen; Ho, Ji-Chen

    2016-01-01

    Background. In Asians, most basal cell carcinomas (BCCs) are pigmented with clear borders. The consensus of 4 mm surgical margin for BCC largely depends on studies in nonpigmented BCCs in Caucasians. However, little is known about recurrences of pigmented BCCs with a narrower surgical margin. We aimed to investigate 5-year recurrence of BCCs, either pigmented or nonpigmented, in Taiwanese with 3 mm surgical margin. Materials and Methods. 143 patients with BCC (M/F = 66/77, average 64 years) were confirmed pathologically from 2002 to 2013. Based on the pathological margin (>1 mm, ≤1 mm, and involved), patients were categorized into the complete excision group (n = 77), histology with close proximity group (n = 43), and unclear surgical margin group (n = 23). Results. Among 143 cases, 105 were pigmented. With standard 3 mm excision, there were 7 recurrences, with 6 of them from nonpigmented BCC group. Logistic regression showed that pigmentation was associated with lower recurrence. Interestingly, 5-year recurrence of completely excised and histology with close proximity BCC (0/77 versus 1/43) was not different statistically. Conclusions. A 3 mm surgical margin is adequate for pigmented BCC. A “wait and see” approach rather than further wide excision is appropriate for BCC with <1 mm free margin. PMID:27652267

  18. Treatment of Pigmented Basal Cell Carcinoma with 3 mm Surgical Margin in Asians.

    PubMed

    Lin, Shang-Hung; Cheng, Yu-Wen; Yang, Yi-Chien; Ho, Ji-Chen; Lee, Chih-Hung

    2016-01-01

    Background. In Asians, most basal cell carcinomas (BCCs) are pigmented with clear borders. The consensus of 4 mm surgical margin for BCC largely depends on studies in nonpigmented BCCs in Caucasians. However, little is known about recurrences of pigmented BCCs with a narrower surgical margin. We aimed to investigate 5-year recurrence of BCCs, either pigmented or nonpigmented, in Taiwanese with 3 mm surgical margin. Materials and Methods. 143 patients with BCC (M/F = 66/77, average 64 years) were confirmed pathologically from 2002 to 2013. Based on the pathological margin (>1 mm, ≤1 mm, and involved), patients were categorized into the complete excision group (n = 77), histology with close proximity group (n = 43), and unclear surgical margin group (n = 23). Results. Among 143 cases, 105 were pigmented. With standard 3 mm excision, there were 7 recurrences, with 6 of them from nonpigmented BCC group. Logistic regression showed that pigmentation was associated with lower recurrence. Interestingly, 5-year recurrence of completely excised and histology with close proximity BCC (0/77 versus 1/43) was not different statistically. Conclusions. A 3 mm surgical margin is adequate for pigmented BCC. A "wait and see" approach rather than further wide excision is appropriate for BCC with <1 mm free margin. PMID:27652267

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

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

    DOE PAGES

    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

  7. 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).

  8. 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

  9. 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

  10. Algal and bacterial activities in acidic (pH 3) strip mine lakes

    SciTech Connect

    Gyure, R.A.; Konopka, A.; Brooks, A.; Doemel, W.

    1987-09-01

    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 H/sub 2/S 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 H/sub 2/S 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 (/sup 14/C)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.

  11. 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

  12. 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

  13. 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.

  14. MM1+2C sporadic Creutzfeldt-Jakob disease presenting as rapidly progressive nonfluent aphasia.

    PubMed

    Allegri, Ricardo F; Bartoloni, Leonardo; Iturry, Mónica; Romero, Carlos; Begué, Christián; Sevlever, Gustavo; Taratuto, Ana Lía

    2014-01-01

    We report a 77-year-old man, presenting with progressive aphasia as an initial symptom, who developed severe dementia over the course of 20 months. Frontal cortex PrPSc western blot was type 2 and codon 129 was MM; brain neuropathology showed cortical vacuoles with perivacuolar PrP immunostaining characteristic of MM2C. Cerebellum showed focal coarse, patchy staining in different sections of the molecular layer, diffuse fine punctuate and coarse PrP immunopositive deposits in the granule cell layer, and focal synaptic immunostaining in the molecular layer, suggestive of MM1+2C by histotyping. This clinical presentation has not yet been described in an MM1+2C subtype by histotyping.

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. High-Efficiency Microiterative Optimization in QM/MM Simulations of Large Flexible Systems.

    PubMed

    Zhang, Yan; Xie, Peng; He, Xiaohu; Han, Keli

    2016-09-13

    We present here a double-optimizations-of-buffer-region (DOBR) microiterative scheme for high-efficiency energy minimizations of large, flexible systems in combined quantum-mechanical/molecular-mechanical (QM/MM) calculations. In the DOBR scheme, an entire system is divided into three regions: the core, buffer, and outer regions. The core region includes QM atoms and the MM atoms within a cutoff distance R1 to the QM atoms (denoted by MM1 atoms), and the buffer region consists of MM atoms within another cutoff distance R2 to MM1 atoms. Each DOBR microcycle involves two steps: First, QM atoms are assigned electrostatic-potential (ESP) charges, and the buffer and outer regions are optimized at the MM level with the core region kept frozen. Second, the core and buffer regions are optimized at the QM/MM level using the electrostatic embedding with the outer region kept frozen. The two steps are repeated until two optimizations converge at one structure. The DOBR scheme was tested in the optimizations of nucleobases solvated in water spheres of 30 Å radius, where the initial geometries were extracted from the trajectories of classical molecular dynamics simulations, and the cutoff distances R1 and R2 were set to 5.0 and 4.0 Å, respectively. For comparisons, the optimizations were also carried out by a "standard" scheme without microiteration and by the two-region microiterative (TRM) method. We found that the averaged number of QM calculations for the DOBR scheme is only ∼1% of that of the standard scheme and ∼6% of the TRM approach. The promising results indicate that the DOBR scheme could significantly increase the efficiency of geometry optimizations for large, flexible systems in QM/MM calculations. PMID:27505170

  6. 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

  7. 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.

  8. [Results of treating forearm bone shaft fractures with a 3.5 mm self compressive plate].

    PubMed

    Małecki, P; Kaleta, M; Tokarowski, A; Kusz, D; Wójcik, B

    1997-01-01

    Results of 29 forearm bones shaft fracture treatment with 3.5mm self compressive plate in 26 patients aged 18-64 (mean 33) are presented. Open reduction with 3.5mm self compressive plate fixation has been performed in all cases. Anderson et al criteria were used to assess functional and radiological outcome. Excellent and good functional results were achieved in 25 cases, one was rated fair, no poor results were observed. PMID:9490253

  9. fireball/amber: An Efficient Local-Orbital DFT QM/MM Method for Biomolecular Systems.

    PubMed

    Mendieta-Moreno, Jesús I; Walker, Ross C; Lewis, James P; Gómez-Puertas, Paulino; Mendieta, Jesús; Ortega, José

    2014-05-13

    In recent years, quantum mechanics/molecular mechanics (QM/MM) methods have become an important computational tool for the study of chemical reactions and other processes in biomolecular systems. In the QM/MM technique, the active region is described by means of QM calculations, while the remainder of the system is described using a MM approach. Because of the complexity of biomolecules and the desire to achieve converged sampling, it is important that the QM method presents a good balance between accuracy and computational efficiency. Here, we report on the implementation of a QM/MM technique that combines a DFT approach specially designed for the study of complex systems using first-principles molecular dynamics simulations (fireball) with the amber force fields and simulation programs. We also present examples of the application of this QM/MM approach to three representative biomolecular systems: the analysis of the effect of electrostatic embedding in the behavior of a salt bridge between an aspartic acid and a lysine residue, a study of the intermediate states for the triosephosphate isomerase catalyzed conversion of dihydroxyacetone phosphate into glyceraldehyde 3-phosphate, and the detailed description, using DFT QM/MM molecular dynamics, of the cleavage of a phosphodiester bond in RNA catalyzed by the enzyme RNase A.

  10. Inhibitor of Apoptosis Proteins (IAPs) as therapeutic targets in Multiple Myeloma (MM)

    PubMed Central

    Ramakrishnan, Vijay; Painuly, Utkarsh; Kimlinger, Teresa; Haug, Jessica; Rajkumar, S. Vincent; Kumar, Shaji

    2014-01-01

    The inhibitor of apoptosis (IAP) proteins plays a critical role in the control of apoptotic machinery, and has been explored as a therapeutic target. Here, we have examined the functional importance of IAPs in multiple myeloma (MM) by using a Smac-mimetic LCL161. We observed that LCL161 was able to potently induce apoptosis in some MM cell lines but not in others. Examining the levels of XIAP, cIAP1 and cIAP2 post LCL161 treatment indicated clear down regulation of both XIAP activity and cIAP1 levels in both the sensitive and less sensitive (resistant) cell lines. cIAP2, however, was not down regulated in the cell line resistant to the drug. siRNA mediated silencing of cIAP2 significantly enhanced the effect of LCL161 indicating the importance of down regulating all IAPs simultaneously for induction of apopotsis in MM cells. LCL161 induced marked up regulation of the Jak2/Stat3 pathway in the resistant MM cell lines. Combining LCL161 with a Jak2 specific inhibitor resulted in synergistic cell death in MM cell lines and patient cells. In addition, combining LCL161 with death inducing ligands clearly showed that LCL161 sensitized MM cells to both FAS-L and TRAIL. PMID:24402161

  11. A Polarizable QM/MM Explicit Solvent Model for Computational Electrochemistry in Water.

    PubMed

    Wang, Lee-Ping; Van Voorhis, Troy

    2012-02-14

    We present a quantum mechanical/molecular mechanical (QM/MM) explicit solvent model for the computation of standard reduction potentials E0. The QM/MM model uses density functional theory (DFT) to model the solute and a polarizable molecular mechanics (MM) force field to describe the solvent. The linear response approximation is applied to estimate E0 from the thermally averaged electron attachment/detachment energies computed in the oxidized and reduced states. Using the QM/MM model, we calculated one-electron E0 values for several aqueous transition-metal complexes and found substantially improved agreement with experiment compared to values obtained from implicit solvent models. A detailed breakdown of the physical effects in the QM/MM model indicates that hydrogen-bonding effects are mainly responsible for the differences in computed values of E0 between the QM/MM and implicit models. Our results highlight the importance of including solute-solvent hydrogen-bonding effects in the theoretical modeling of redox processes.

  12. Assimilation of GMS-5 satellite winds using nudging method with MM5

    NASA Astrophysics Data System (ADS)

    Gao, Shanhong; Wu, Zengmao; Yang, Bo

    2006-09-01

    With the aid of Meteorological Information Composite and Processing System (MICAPS), satellite wind vectors derived from the Geostationary Meteorological Statellite-5 (GMS-5) and retrieved by National Satellite Meteorology Center of China (NSMC) can be obtained. Based on the nudging method built in the fifth-generation Mesoscale Model (MM5) of Pennsylvania State University and National Center for Atmospheric Research, a data preprocessor is developed to convert these satellite wind vectors to those with specified format required in MM5. To examine the data preprocessor and evaluate the impact of satellite winds from GMS-5 on MM5 simulations, a series of numerical experimental forecasts consisting of four typhoon cases in 2002 are designed and implemented. The results show that the preprocessor can process satellite winds smoothly and MM5 model runs successfully with a little extra computational load during ingesting these winds, and that assimilation of satellite winds by MM5 nudging method can obviously improve typhoon track forecast but contributes a little to typhoon intensity forecast. The impact of the satellite winds depends heavily upon whether the typhoon bogussing scheme in MM5 was turned on or not. The data preprocessor developed in this paper not only can treat GMS-5 satellite winds but also has capability with little modification to process derived winds from other geostationary satellites.

  13. 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 ...

  14. PH DEPENDENT TOXICITY OF FIVE METALS TO THREE MARINE ORGANISMS

    EPA Science Inventory

    The pH of natural marine systems is relatively stable; this may explain why metal toxicity changes with pH have not been well documented. However, changes in metal toxicity with pH in marine waters are of concern in toxicity testing. During porewater toxicity testing pH can chang...

  15. 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...

  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. 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...

  18. 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...

  19. 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

  20. Not Your Father's Ph.D.

    ERIC Educational Resources Information Center

    Withrow, Brandon G.

    2008-01-01

    This article describes how the author, a devoted blogger, confronts his fear that his virtual life is damaging his career prospects in academe. As a new Ph.D. in religious studies, the author has every reason to believe he will find a tenure-track job. He has read the numbers and know that, on average, job candidates spend two to five years in…

  1. Acidification due to microbial dechlorination near a trichloroethene DNAPL is overcome with pH buffer or formate as electron donor: experimental demonstration in diffusion-cells.

    PubMed

    Philips, Jo; Maes, Nele; Springael, Dirk; Smolders, Erik

    2013-04-01

    Acidification due to microbial dechlorination of trichloroethene (TCE) can limit the bio-enhanced dissolution of TCE dense non-aqueous phase liquid (DNAPL). This study related the dissolution enhancement of a TCE DNAPL to the pH buffer capacity of the medium and the type of electron donor used. In batch systems, dechlorination was optimal at pH7.1-7.5, but was completely inhibited below pH6.2. In addition, dechlorination in batch systems led to a smaller pH decrease at an increasing pH buffer capacity or with the use of formate instead of lactate as electron donor. Subsequently, bio-enhanced TCE DNAPL dissolution was quantified in diffusion-cells with a 5.5 cm central sand layer, separating a TCE DNAPL layer from an aqueous top layer. Three different pH buffer capacities (2.9 mM-17.9 mM MOPS) and lactate or formate as electron donor were applied. In the lactate fed diffusion-cells, the DNAPL dissolution enhancement factor increased from 1.5 to 2.2 with an increase of the pH buffer capacity. In contrast, in the formate fed diffusion-cells, the DNAPL dissolution enhancement factor (2.4±0.3) was unaffected by the pH buffer capacity. Measurement of the pore water pH confirmed that the pH decreased less with an increased pH buffer capacity or with formate instead of lactate as electron donor. These results suggest that the significant impact of acidification on bio-enhanced DNAPL dissolution can be overcome by the amendment of a pH buffer or by applying a non acidifying electron donor like formate.

  2. Coordinated NIR/mm observations of flare emission from Sagittarius A*

    NASA Astrophysics Data System (ADS)

    Kunneriath, D.; Witzel, G.; Eckart, A.; Zamaninasab, M.; Gießübel, R.; Schödel, R.; Baganoff, F. K.; Morris, M. R.; Dovčiak, M.; Duschl, W. J.; García-Marín, M.; Karas, V.; König, S.; Krichbaum, T. P.; Krips, M.; Lu, R.-S.; Mauerhan, J.; Moultaka, J.; Mužić, K.; Sabha, N.; Najarro, F.; Pott, J.-U.; Schuster, K. F.; Sjouwerman, L. O.; Straubmeier, C.; Thum, C.; Vogel, S. N.; Teuben, P.; Weiss, A.; Wiesemeyer, H.; Zensus, J. A.

    2010-07-01

    Context. We report on a successful, simultaneous observation and modelling of the millimeter (mm) to near-infrared (NIR) flare emission of the Sgr A* counterpart associated with the supermassive (4 × 106 M⊙) black hole at the Galactic centre (GC). We present a mm/sub-mm light curve of Sgr A* with one of the highest quality continuous time coverages. Aims: We study and model the physical processes giving rise to the variable emission of Sgr A*. Methods: Our non-relativistic modelling is based on simultaneous observations carried out in May 2007 and 2008, using the NACO adaptive optics (AO) instrument at the ESO's VLT and the mm telescope arrays CARMA in California, ATCA in Australia, and the 30 m IRAM telescope in Spain. We emphasize the importance of multi-wavelength simultaneous fitting as a tool for imposing adequate constraints on the flare modelling. We present a new method for obtaining concatenated light curves of the compact mm-source Sgr A* from single dish telescopes and interferometers in the presence of significant flux density contributions from an extended and only partially resolved source. Results: The observations detect flaring activity in both the mm domain and the NIR. Inspection and modelling of the light curves show that in the case of the flare event on 17 May 2007, the mm emission follows the NIR flare emission with a delay of 1.5±0.5 h. On 15 May 2007, the NIR flare emission is also followed by elevated mm-emission. We explain the flare emission delay by an adiabatic expansion of source components. For two other NIR flares, we can only provide an upper limit to any accompanying mm-emission of about 0.2 Jy. The derived physical quantities that describe the flare emission give a source component expansion speed of vexp ~ 0.005c-0.017c, source sizes of about one Schwarzschild radius, flux densities of a few Janskys, and spectral indices of α = 0.6 to 1.3. These source components peak in the THz regime. Conclusions: These parameters suggest

  3. Use of a Genetically Enhanced, Pediocin-Producing Starter Culture, Lactococcus lactis subsp. lactis MM217, To Control Listeria monocytogenes in Cheddar Cheese

    PubMed Central

    Buyong, Nurliza; Kok, Jan; Luchansky, John B.

    1998-01-01

    Cheddar cheese was prepared with Lactococcus lactis subsp. lactis MM217, a starter culture which contains pMC117 coding for pediocin PA-1. About 75 liters of pasteurized milk (containing ca. 3.6% fat) was inoculated with strain MM217 (ca. 106 CFU per ml) and a mixture of three Listeria monocytogenes strains (ca. 103 CFU per ml). The viability of the pathogen and the activity of pediocin in the cheese were monitored at appropriate intervals throughout the manufacturing process and during ripening at 8°C for 6 months. In control cheese made with the isogenic, non-pediocin-producing starter culture L. lactis subsp. lactis MM210, the counts of the pathogen increased to about 107 CFU per g after 2 weeks of ripening and then gradually decreased to about 103 CFU per g after 6 months. In the experimental cheese made with strain MM217, the counts of L. monocytogenes decreased to 102 CFU per g within 1 week of ripening and then decreased to about 10 CFU per g within 3 months. The average titer of pediocin in the experimental cheese decreased from approximately 64,000 arbitrary units (AU) per g after 1 day to 2,000 AU per g after 6 months. No pediocin activity (<200 AU per g) was detected in the control cheese. Also, the presence of pMC117 in strain MM217 did not alter the cheese-making quality of the starter culture, as the rates of acid production, the pH values, and the levels of moisture, NaCl, and fat of the control cheese and the experimental cheese were similar. Our data revealed that pediocin-producing starter cultures have significant potential for protecting natural cheese against L. monocytogenes. PMID:9835572

  4. 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…

  5. Pyrite oxidation at circumneutral pH

    NASA Astrophysics Data System (ADS)

    Moses, Carl O.; Herman, Janet S.

    1991-02-01

    Previous studies of pyrite oxidation kinetics have concentrated primarily on the reaction at low pH, where Fe(III) has been assumed to be the dominant oxidant. Studies at circumneutral pH, necessitated by effective pH buffering in some pyrite oxidation systems, have often implicitly assumed that the dominant oxidant must be dissolved oxygen (DO), owing to the diminished solubility of Fe(III). In fact, Fe(III)(aq) is an effective pyrite oxidant at circumneutral pH, but the reaction cannot be sustained in the absence of DO. The purpose of this experimental study was to ascertain the relative roles of Fe(III) and DO in pyrite oxidation at circumneutral pH. The rate of pyrite oxidation was first-order with respect to the ratio of surface area to solution volume. Direct determinations of both Fe(II) (aq)> and Fe(III) (aq) demonstrated a dramatic loss of Fe(II) from the solution phase in excess of the loss for which oxidation alone could account. Based on rate data, we have concluded that Fe(II) is adsorbed onto the pyrite surface. Furthermore, Fe(II) is preferred as an adsorbate to Fe(III), which we attribute to both electrostatic and acid-base selectivity. We also found that the rate of pyrite oxidation by either Fe(III) (aq) or DO is reduced in the presence of aqueous Fe(II), which leads us to conclude that, under most natural conditions, neither Fe(III) (aq) nor DO directly attacks the pyrite surface. The present evidence suggests a mechanism for pyrite oxidation that involves adsorbed Fe( II ) giving up electrons to DO and the resulting Fe(III) rapidly accepting electrons from the pyrite. The adsorbed Fe is, thus, cyclically oxidized and reduced, while it acts as a conduit for electrons traveling from pyrite to DO. Oxygen is transferred from the hydration sphere of the adsorbed Fe to pyrite S. The cycle of adsorbed Fe oxidation and reduction and the successive addition of oxygen to pyrite S continues until a stable sulfoxy species dissociates from the surface. Prior

  6. 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…

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. Compact, mission configurable mm-wave spectrometer based on a channel drop filter

    NASA Astrophysics Data System (ADS)

    Smirnova, Evgenya I.; Bailey, Aimee G.; Earley, Lawrence M.; Kurennoy, Sergey S.

    2007-04-01

    We have developed a novel mm-wave spectrometer based on a Photonic Band Gap (PBG) channel-drop filter (CDF). There is a need for a compact wide-band versatile and configurable mm-wave spectrometer for applications in mm-wave communications and remote sensing. CDFs present us with a unique means for filtering frequencies at mm-waves. CDF is a novel concept allowing filtering the frequency spectra and channeling selected frequencies into separate waveguides through a PBG structure. We have designed a spectrometer with a CDF working in the frequency range of 90-130 GHz. The CDF can be connected to any type of antenna and detector. A large ground based outdoor antenna can be used for remote sensing with radars. A compact antenna can be used for indoor or space applications. The signal in the waveguide channels can be measured with any type of sensor such as a cooled bolometer or a room temperature mm-wave diode. The size of the spectrometer is under 5 inches by 5 inches and just a quarter of an inch in thick. Multiple filters can be stacked together to construct a mission specific package. We propose to construct the filter with silicon rods on a 100mm silicon wafer using MEMS technology. We will then evaluate the filter at our mm-wave laboratory to demonstrate the channeling of frequencies in a proof-of-principle experiment at 100GHz. This technology will work well for frequencies from 60GHz to 1000GHz.

  12. Transitions from alkaline spots to regular bands during pH pattern formation at the plasmalemma of Chara cells.

    PubMed

    Bulychev, A A; Zykov, S V; Rubin, A B; Müller, S C

    2003-05-01

    A scanning pH-microprobe was used to study pH patterns near the surface of Chara corallina cells at various light intensities and during light-induced transitions from homogeneous pH distribution to alternating pH bands. In the irradiance (PAR) range 4-400 micromol quanta m(-2) s(-1), the sustained pH profiles consisted of alternating acid and alkaline bands with a characteristic length of 7-10 mm and pH shifts as large as 2-3 units. At lower irradiance, the number of alkaline bands decreased while the amplitude of remaining peaks stayed high. On cyclic changes in light intensity, a hysteresis of pH banding was observed: the pH bands tolerated low irradiance in weakening light, but higher irradiance was required for their emergence after dark adaptation of the cell. The pH profiles measured for different paths of electrode scanning suggest that the pH pattern at low light level represents patches coexisting with bands. The exposure of the cell to high-intensity light led to formation of radially symmetrical bands. Transformations of the pH pattern induced by lowering the light intensity were similar to those induced by transcellular electric current (1.5-3 microA). The data suggest that band formation at the plasmalemma of Chara cells proceeds through the initial appearance of multiple patches with a localized H(+)-transporting activity and subsequent spot rearrangements (fusion, deletions, widening), leading to establishment of alternating bands.

  13. Iridium oxide pH sensor for biomedical applications. Case urea-urease in real urine samples.

    PubMed

    Prats-Alfonso, Elisabet; Abad, Llibertat; Casañ-Pastor, Nieves; Gonzalo-Ruiz, Javier; Baldrich, Eva

    2013-01-15

    This work demonstrates the implementation of iridium oxide films (IROF) grown on silicon-based thin-film platinum microelectrodes, their utilization as a pH sensor, and their successful formatting into a urea pH sensor. In this context, Pt electrodes were fabricated on Silicon by using standard photolithography and lift-off procedures and IROF thin films were growth by a dynamic oxidation electrodeposition method (AEIROF). The AEIROF pH sensor reported showed a super-Nerstian (72.9±0.9mV/pH) response between pH 3 and 11, with residual standard deviation of both repeatability and reproducibility below 5%, and resolution of 0.03 pH units. For their application as urea pH sensors, AEIROF electrodes were reversibly modified with urease-coated magnetic microparticles (MP) using a magnet. The urea pH sensor provided fast detection of urea between 78μM and 20mM in saline solution, in sample volumes of just 50μL. The applicability to urea determination in real urine samples is discussed.

  14. QM/MM Minimum Free Energy Path: Methodology and Application to Triosephosphate Isomerase.

    PubMed

    Hu, Hao; Lu, Zhenyu; Yang, Weitao

    2007-03-01

    Structural and energetic changes are two important characteristic properties of a chemical reaction process. In the condensed phase, studying these two properties is very challenging because of the great computational cost associated with the quantum mechanical calculations and phase space sampling. Although the combined quantum mechanics/molecular mechanics (QM/MM) approach significantly reduces the amount of the quantum mechanical calculations and facilitates the simulation of solution phase and enzyme catalyzed reactions, the required quantum mechanical calculations remain quite expensive and extensive sampling can be achieved routinely only with semiempirical quantum mechanical methods. QM/MM simulations with ab initio QM methods, therefore, are often restricted to narrow regions of the potential energy surface such as the reactant, product and transition state, or the minimum energy path. Such ab initio QM/MM calculations have previously been performed with the QM/MM-Free Energy (QM/MM-FE) method of Zhang et al.1 to generate the free energy profile along the reaction coordinate using free energy perturbation calculations at fixed structures of the QM subsystems. Results obtained with the QM/MM-FE method depend on the determination of the minimum energy reaction path, which is based on local conformations of the protein/solvent environment and can be difficult to obtain in practice. To overcome the difficulties associated with the QM/MM-FE method and to further enhance the sampling of the MM environment conformations, we develop here a new method to determine the QM/MM minimum free energy path (QM/MM-MFEP) for chemical reaction processes in solution and in enzymes. Within the QM/MM framework, we express the free energy of the system as a function of the QM conformation, thus leading to a simplified potential of mean force (PMF) description for the thermodynamics of the system. The free energy difference between two QM conformations is evaluated by the QM/MM

  15. 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

  16. 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.

  17. 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

  18. Relations structurales entre U 3O 8 et quelques fluorures mixtes de formules M2M' 3F 11, MM' 2F 7 et MM' 3F 10

    NASA Astrophysics Data System (ADS)

    Aléonard, S.; Le Fur, Y.; Champarnaud-Mesjard, J. C.; Frit, B.; Roux, M. Th.

    1983-01-01

    U 3O 8 oxide, as well as M2M' 3F 11, MM' 2F 7 and MM' 3F 10 fluorides, with M = Rb, Tl, Cs, NH 4 and M' = In, Lu, Yb, Tm, is described as the regular repetition according to the … A-A-A … sequence of identical and parallel sheets of edge-and corner-sharing M'F 7 or UO 7 pentagonal bipyramids and M'F 6 octahedra. M' and U atoms are systematically located at the lattice points of a pseudohexagonal network, but in the fluorides some of these lattice points are vacant, producing hexagonal tunnels in which M atoms are located. It is shown that in the two kinds of compounds the same linear chains and M' 3X17 groups of pentagonal bipyramids are present, and that the transformation of the U 3O 8 structure into the fluorides can be achieved by an ordered substitution of some linear … UOUO … chains by … M- M- M … chains. All these structures can be described with the same structural model based on the chemical twinning principle.

  19. POLYVIEW-MM: web-based platform for animation and analysis of molecular simulations.

    PubMed

    Porollo, Aleksey; Meller, Jaroslaw

    2010-07-01

    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.

  20. Ultrasonic micro-motor using miniature piezoelectric tube with diameter of 1.0 mm.

    PubMed

    Zhang, Hui; Dong, Shu-xiang; Zhang, Shu-yi; Wang, Tian-hua; Zhang, Zhong-ning; Fan, Li

    2006-12-22

    At the present moment, the smallest piezoelectric ultrasonic micro-motors utilizing miniature PZT piezoelectric ceramic tubes were developed. The motor consists of a PZT-metal composite tube stator, two steel rotors and a thin shaft that keeps the two rotors pressing on both ends of the stator elastically. The dimensions of the PZT tube are 1.0 mm in outer diameter, 0.6 mm in inner diameter and 5.0 mm in length. The diameter and total length of the assembled micro-motor is 1.0 mm and 8 mm (including an adjusting spring), respectively. The tube-type micro-motor is driven by two pairs of alternative voltages with phase shift 90 degrees between the adjacent electrodes and operated in the first circular-bending vibration mode of the stator with the resonance frequency about 58 kHz. The experimental results show that the tube-type micro-motors have perfect performances: (i) high rotation frequency over 3000 rpm and (ii) large starting torque over 7.8 microN m under the conditions of the input voltage of 110 V(p-p) and the resonance frequency. The micro-motor is well suitable for operating in micro-spaces, such as in intravascular, micro-robots and micro-craft applications.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  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. 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.

  8. Effect of propionate toxicity on methanogen-enriched sludge, Methanobrevibacter smithii, and Methanospirillum hungatii at different pH values.

    PubMed Central

    Barredo, M S; Evison, L M

    1991-01-01

    The effect of propionate toxicity at different pH values (6.5, 7.0, and 8.0) on methanogen-enriched sludge. Methanobrevibacter smithii, and Methanospirillum hungatii was studied. Organisms were grown in Balch medium 3 in Hungate tubes, and toxicity was characterized by a decrease in production of methane and in bacterial numbers. Propionate inhibited bacterial growth and cumulative methane production at concentrations as low as 20 mM. In the absence of propionate, the methanogen-enriched sludge and M. smithii showed better cumulative methane production at pH 6.5 and 7.0 than at pH 8.0. However, in the presence of propionate, these organisms showed better cumulative methane production at pH 8.0. M. hungatii differed in its behavior; the best values of cumulative methane production for this organism occurred at pH 7.0. Bacterial numbers reflected the microbial response to the presence of propionate. The highest counts of methanogenic bacteria were observed at pH 6.5 and 8.0. The numbers of methanogens were affected by the presence of propionate even at concentrations as low as 20 or 30 mM; at propionate concentrations above 80 mM, the methanogen count was affected by at least 2 orders of magnitude. Upon comparison of the responses of the pure cultures and the methanogen-enriched sludge to increasing propionate concentrations, it was found that the sensitivity of the pure cultures was similar to that of the methanogens in the sludge. PMID:1872605

  9. 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

  10. Glucose metabolism and glutamate analog acutely alkalinize pH of insulin secretory vesicles of pancreatic beta-cells.

    PubMed

    Eto, Kazuhiro; Yamashita, Tokuyuki; Hirose, Kenzo; Tsubamoto, Yoshiharu; Ainscow, Edward K; Rutter, Guy A; Kimura, Satoshi; Noda, Mitsuhiko; Iino, Masamitsu; Kadowaki, Takashi

    2003-08-01

    We studied acute changes of secretory vesicle pH in pancreatic beta-cells with a fluorescent pH indicator, lysosensor green DND-189. Fluorescence was decreased by 0.66 +/- 0.10% at 149 +/- 16 s with 22.2 mM glucose stimulation, indicating that vesicular pH was alkalinized by approximately 0.016 unit. Glucose-responsive pH increase was observed when cytosolic Ca2+ influx was blocked but disappeared when an inhibitor of glycolysis or mitochondrial ATP synthase was present. Glutamate dimethyl ester (GME), a plasma membrane-permeable analog of glutamate, potentiated glucose-stimulated insulin secretion at 5 mM without changing cellular ATP content or cytosolic Ca2+ concentration ([Ca2+]). Application of GME at basal glucose concentration decreased DND-189 fluorescence by 0.83 +/- 0.19% at 38 +/- 2 s. These results indicated that the acutely alkalinizing effect of glucose on beta-cell secretory vesicle pH was dependent on glucose metabolism but independent of modulations of cytosolic [Ca2+]. Moreover, glutamate derived from glucose may be one of the mediators of this alkalinizing effect of glucose, which may have potential relevance to the alteration of secretory function by glutamate.

  11. Bioelectricity production from food waste leachate using microbial fuel cells: effect of NaCl and pH.

    PubMed

    Li, Xiao Min; Cheng, Ka Yu; Wong, Jonathan W C

    2013-12-01

    Microbial fuel cells are a promising technology for simultaneous treatment and energy recovery from food waste leachate. This study evaluates the effects of NaCl (0-150 mM) and pH on the treatment of food waste leachate using microbial fuel cells. The food waste leachate amended with 100mM NaCl enabled the highest maximum power density (1000 mW/m(3)) and lowest internal resistance (371Ω). Increasing the anodic pH gradually from acidic to alkaline conditions (pH 4-9) resulted in a gradual increase in maximum power density to 9956 mW/m(3) and decrease in internal cell resistance to 35.3Ω. The coulombic efficiency obtained under acidic conditions was only 17.8%, but increased significantly to 60.0% and 63.4% in the neutral and alkaline pH's MFCs, respectively. Maintaining a narrow pH window (6.3-7.6) was essential for efficient bioelectricity production and COD removal using microbial fuel cells for the treatment of food waste leachate.

  12. 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.

  13. 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

  14. 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.

  15. The panacea toolbox of a PhD biomedical student

    PubMed Central

    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

  16. Efficient approach to obtain free energy gradient using QM/MM MD simulation

    SciTech Connect

    Asada, Toshio; Koseki, Shiro; Ando, Kanta

    2015-12-31

    The efficient computational approach denoted as charge and atom dipole response kernel (CDRK) model to consider polarization effects of the quantum mechanical (QM) region is described using the charge response and the atom dipole response kernels for free energy gradient (FEG) calculations in the quantum mechanical/molecular mechanical (QM/MM) method. CDRK model can reasonably reproduce energies and also energy gradients of QM and MM atoms obtained by expensive QM/MM calculations in a drastically reduced computational time. This model is applied on the acylation reaction in hydrated trypsin-BPTI complex to optimize the reaction path on the free energy surface by means of FEG and the nudged elastic band (NEB) method.

  17. 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

  18. Three-degree-of-freedom ultrasonic motor using a 5-mm-diameter piezoelectric ceramic tube.

    PubMed

    Mingsen Guo; Junhui Hu; Hua Zhu; Chunsheng Zhao; Shuxiang Dong

    2013-07-01

    A small three-degree-of-freedom ultrasonic motor has been developed using a simple piezoelectric lead zirconate titanate (PZT)-tube stator (OD 5 mm, ID 3 mm, length 15 mm). The stator drives a ball-rotor into rotational motion around one of three orthogonal (x-, y-, and z-) axes by combing the first longitudinal and second bending vibration modes. A motor prototype was fabricated and characterized; its performance was superior to those of previous motors made with a PZT ceramic/metal composite stator of comparable size. The method for further improving the performance was discussed. The motor can be further miniaturized and it has potential to be applied to medical microrobots, endoscopes or micro laparoscopic devices, and cell manipulation devices.

  19. Recording and wear characteristics of 4 and 8 mm helical scan tapes

    NASA Technical Reports Server (NTRS)

    Peter, Klaus J.; Speliotis, Dennis E.

    1993-01-01

    Performance data of media on helical scan tape systems (4 and 8 mm) is presented and various types of media are compared. All measurements were performed on a standard MediaLogic model ML4500 Tape Evaluator System with a Flash Converter option for time based measurements. The 8 mm tapes are tested on an Exabyte 8200 drive and 4 mm tapes on an Archive Python drive; in both cases, the head transformer is directly connected to a Media Logic Read/Write circuit and test electronics. The drive functions only as a tape transport and its data recover circuits are not used. Signal to Noise, PW 50, Peak Shift and Wear Test data is used to compare the performance of MP (metal particle), BaFe, and metal evaporate (ME). ME tape is the clear winner in magnetic performance but its susceptibility to wear and corrosion, make it less than ideal for data storage.

  20. Ultrastructural response of rat lung to 90 days' exposure to oxygen at 450 mm Hg

    NASA Technical Reports Server (NTRS)

    Harrison, G. A.

    1974-01-01

    Young Sprague-Dawley rats were exposed to 100% oxygen at 450 mm Hg in constant environment capsules for 90 days. Lung tissue examined by electron microscopy revealed a number of changes, many similar to those observed after exposure to oxygen at 760 mm Hg for shorter periods of time. Alterations in vesicle size and number and in mitochondrial matrix and cristae appear in both the endothelial and epithelial cells. Blebbing and rarefication of cytoplasm occur in both cell layers of the alveolo-capillary wall. Also seen are fluid in the basement membrane, platelets in the capillaries, and alveolar fluid and debris. All of these alterations occur at 1 atm exposure. However, after exposure to 450 mm Hg the changes are not as widespread nor as destructive as they are at the higher pressure.