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Sample records for volume-weighted ph values

  1. Cosmological Measures without Volume Weighting

    CERN Document Server

    Page, Don N

    2008-01-01

    Many cosmologists (myself included) have advocated volume weighting for the cosmological measure problem, weighting spatial hypersurfaces by their volume. However, this often leads to the Boltzmann brain problem, that almost all observations would be by momentary Boltzmann brains that arise very briefly as quantum fluctuations in the late universe when it has expanded to a huge size, so that our observations (too ordered for Boltzmann brains) would be highly atypical and unlikely. Here it is suggested that volume weighting may be a mistake. Volume averaging is advocated as an alternative. One consequence would be a loss of the argument for eternal inflation.

  2. Replication Regulates Volume Weighting in Quantum Cosmology

    CERN Document Server

    Hartle, James

    2009-01-01

    Probabilities for observations in cosmology are conditioned both on the universe's quantum state and on local data specifying the observational situation. We show the quantum state defines a measure for prediction through such conditional probabilities that is well behaved for spatially large or infinite universes when the probabilities that our data is replicated are taken into account. In histories where our data are rare volume weighting connects top-down probabilities conditioned on both the data and the quantum state to the bottom-up probabilities conditioned on the quantum state alone. We apply these principles to a calculation of the number of inflationary e-folds in a homogeneous, isotropic minisuperspace model with a single scalar field moving in a quadratic potential. We find that volume weighting is justified and the top-down probabilities favor a large number of e-folds.

  3. Influence of pH value on chromate-free conversion coating for magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    WENG Wen-ping; CHEN Qi; ZHANG Hui; ZHONG Hao; YAN Yun-qi

    2006-01-01

    Many factors were found to have effects on the conversion coatings for AZ31 alloy, alloy the most important one in producing high quality conversion coatings is found to be the control of the pH value. The influence of pH value on the conversion coating including color, thickness, adhesion and surface morphology was studied. The performance of conversion coating was examined by cross cut test, SEM method and salt immersion. The results show that the variation of pH value causes surface treatment process unstably. The conversion coating can obtain as pH value ranging from 3.0 to 5.0, while it presents dark, thick and bad adhesion under lower pH value. The conversion coatings have good combination of thickness and adhesion when pH value ranging from 4.0 to 4.5, and it exhibits a good corrosion resistance.

  4. PREPARATION OF ULTRA-LOW VOLUME WEIGHT AUTOCLAVED AERATED CONCRETE

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    Ondrej Koutny

    2016-12-01

    Full Text Available Autoclaved aerated concrete is a modern construction material that gains its popularity especially due to its thermal insulation performance resulting from low volume weight and porous structure with sufficient mechanical strength. Nowadays, there are attempts to use this material for thermal insulation purposes and to replace current systems, which have many disadvantages, mainly concerning durability. The key for improvement of thermal insulation properties is therefore obtaining a material based on autoclaved aerated concrete with extremely low volume weight (below 200 kg/m ³ ensuring good thermal isolation properties, but with sufficient mechanical properties to allow easy manipulation. This material can be prepared by foaming very fine powder materials such as silica fume or very finely ground sand. This paper deals with the possibilities of preparation and summarizes the basic requirements for successful preparation of such a material.

  5. PH Value" Design Show Unveils the Shanghai Dream%"PH Value" Design Show Unveils the Shanghai Dream

    Institute of Scientific and Technical Information of China (English)

    Wanzy Wang

    2012-01-01

    "PH Value" Design Show, organized by China National Textile and Apparel Council (CNTAC), undertaken by the Sub- Council of Textile Industry, CCPIT (CCPIT-TEX), China Knitting industry Association, and China National Garment Association (CNGA), will be held from October 22rid to 23rd in Shanghai, unveiling the charming mysteries of "Shanghai Dream".

  6. Low medium pH value enhances anthocyanin accumulation in Malus crabapple leaves.

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    Yanchen Zhang

    Full Text Available Anthocyanin is a critical factor involved in coloration of plant tissues, but the mechanism how medium pH values affect anthocyanin accumulation in woody plants is unknown. We analyzed anthocyanin composition and the expression of elements encoding anthocyanin and flavonols biosynthesis underlying different medium pH values by using three different leave color type cultivars. HPLC analysis demonstrated that high medium pH values treatment induced a dramatic decrease in the concentration of cyaniding in crabapple leaves. Conversely, the high medium pH values induced up-regulation of the content of flavones and flavonols, suggesting that low pH treatment-induced anthocyanin accumulation. Quantitative real time PCR experiment showed the expression level of anthocyanidin synthase (McANS and uridine diphosphate glucose flavonoid 3-O-glucosyltransferase (McUFGT was up-regulated by low pH values treatment, and high medium pH value treatment up-regulate the transcription level of flavonol synthase (McFLS. Meanwhile, several MYB TFs have been suggested in the regulation of pH responses. These results strongly indicate that the low pH treatment-induced anthocyanin accumulation is mediated by the variation of mRNA transcription of the anthocyanin biosynthetic genes.

  7. Photoionization of aromatic amino acid at different pH values

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The photoioization of aromatic amino acid in solutions of different pH values were investigated by 248 nm laser flash photolysis. The results showed that the photoionizations of tyrosine and tryptophan were affected by pH value of solution, but phenylalanine was not. The ionization was in favor of monophotonic process at high pH value and of biphotonic process at low pH value. The mechanisms of pH effect on photoionization of tyrosine and tryptophan were the deprotonation of phenolic hydroxyl group and the deprotonation of>NH on the indole ring respectively. Our results explain the discrepancy of values for the yield of hydrated electron obtained by other investigators.

  8. Measurement of individual intracellular pH and membrane potential values in living cells

    Science.gov (United States)

    Slavik, Jan; Lanz, Edvard; Cimprich, Petr

    1999-07-01

    It was assumed that each cell is a homogeneous suspension may have a slightly different pH and membrane potential. A wide range of pH-sensitive fluorescent dyes BCECF, SNARF, FITC, carboxyfluorescein, fluorescein and pyranine have been carefully tested for the accuracy and reliability of their pH-response inside living cells. The intracellular milieu was simulated by a series of mineral buffers with addition of proteins. The pH values have been determined from the excitation ratios 490/435 nm for BCECF, FITC, carboxyfluorescein and fluorescein, and 450/400 nm for pyranine, emission ratios 518/529 nm for BCECF and 635/590 nm for SNARF. The spectrally determined values were then compared with the pH values of buffers measured by a glass electrode. Using the data from the calibration procedure, we evaluated individual intracellular pH values of a large number of cells within one cell population. The confocal ratio fluorescence microscopy revealed pH maps from which both cytoplasmic and vacuolar pH values could be determine, flow cytometry gave enormous amount of average intracellular pH values of individual cells of a whole cell population. Each cell population exhibited significant differences in both cytoplasmic pH values among individual cells. The pH distribution of a typical cell population appeared to fit a Gaussian curve. In yeast it was a Gaussian curve with half- width values around 0.4 pH unit. The men pH values depended on the growth phase, H-ATPase activity and external pH values. The preliminary result with the new membrane potential dye tetramethylrhodamine methyl ester indicated that similarly to pH values, there is a heterogeneity in membrane potential values among cell sin one cell population. The data presented above suggest that each ell behaves as an individual with an individual set up of its metabolism. This 'fine tuning' of the metabolism result in slightly higher or lower pH or membrane potential values that can be detected by fluorescence

  9. Yogurt made from milk heated at different pH values.

    Science.gov (United States)

    Ozcan, Tulay; Horne, David S; Lucey, John A

    2015-10-01

    Milk for yogurt manufacture is subjected to high heat treatment to denature whey proteins. Low milk pH values (≤ 6.5) at heating result in most denatured whey proteins becoming associated with casein micelles, whereas high milk pH values (≥ 7.0) at heating result in the formation of mostly soluble (nonmicellar) denatured whey protein complexes. There are conflicting reports on the relative importance of soluble and casein-bound whey protein aggregates on the properties of acid gels. Prior studies investigating the effect of pH of milk at heating used model gels in which milk was acidified by glucono-δ-lactone; in this study, we prepared yogurt gels using commercial starter cultures. Model acid gels can have very different texture and physical properties from those made by fermentation with starter cultures. In this study, we investigated the effects of different pH values of milk at heating on the rheological, light backscatter, and microstructural properties of yogurt gels. Reconstituted skim milk was adjusted to pH values 6.2, 6.7, and 7.2 and heated at 85°C for 30 min. A portion of the heated milk samples was readjusted back to pH 6.7 after heating. Milks were inoculated with 3% (wt/wt) yogurt starter culture and incubated at 40°C until pH 4.6. Gel formation was monitored using dynamic oscillatory rheology, and parameters measured included the storage modulus (G') and loss tangent (LT) values. Light-backscattering properties, such as the backscatter ratio (R) and the first derivative of light backscatter ratio (R'), were also monitored during fermentation. Fluorescence microscopy was used to observe gel microstructure. The G' values at pH 4.6 were highest in gels made from milk heated at pH 6.7 and lowest in milk heated at pH 6.2, with or without pH adjustment after heating. The G' values at pH 4.6 were lower in samples after adjustment back to pH 6.7 after heating. No maximum in the LT parameter was observed during gelation for yogurts made from milk

  10. The pH Value of Fungicide, Insecticide and Mineral Fertilizer Mixtures Depending on Water Quality

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    Dušanka Inđić

    2008-01-01

    Full Text Available The paper deals with the effect of water quality on the pH value of fungicides, insecticides, mineral fertilizers and their mixtures. The fungicides propineb (Antracol WP-70 and mancozeb (Dithane M-70, insecticides pirimiphos-methyl (Actellic-50 and imidacloprid(Confidor 200-SL, several fertilizers (Ferticare I, Ferticare II, Ferticare III and Wuxal Super and their mixtures were analyzed for pH value under laboratory conditions using a potentiometric pH meter. Measurements were made directly after preparation or mixing with tap and well water and 24 hours later. Tap water exhibited a neutral reaction. A slightly alkaline reaction of well water was mostlikely due to high ammonium content. The suspensions of Antracol WP-70 exhibited slightly alkaline reactions with both water types during 24 hours. The spray liquids of Dithane M-70 mixed with tap or well water had neutral reaction after preparation and slightly alkaline reaction after 24 hours. The emulsions of Actellic-50 showed neutral reaction with both water types, followed by a pH increase in tap water after 24 hours. The solutions of Confidor200-SL had a slightly alkaline reaction after mixing and the pH value increased with both water types after 24 hours. It is therefore recommended to apply these insecticides directly after preparation. Mineral fertilizers considerably reduced pH values of the fungicide and insecticide components in double and triple mixtures, especially Ferticare nutrients which had a moderately acid reaction. Wuxal Super had a neutral reaction with both water types.The mixtures with well water increased pH values, which indicates that water pH does affect the pH value of the mixture. Both individual fertilizers and all mixtures (double and triple with Ferticare had pH values between 2.4 and 6, which allows their active liquids to be stored for 12 to 24 hours. The suspensions (Antracol WP-70, double and triple mixtures, emulsions (Actellic-50 and Actellic-50+Wuxal Super

  11. Dependence of Nanofluid Viscosity on Particle Size and pH Value

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jia-Fei; LUO Zhong-Yang; NI Ming-Jiang; CEN Ke-Fa

    2009-01-01

    We investigate the viscosity of silicon dioxide nanofluid at different particle sizes and pH values considering nanoparticle aggregation.The experimental and simulation results indicate that nanoparticle size is of crucial importance to the viscosity of the nanofluid due to aggregation.As the nanoparticle size decreases,the viscosity becomes much more dependent on the volume fraction.Moreover,when the nanoparticle diameter is smaller than 20 rim,the viscosity is closely related to the pH of the nanofluid,and fluctuates with pH values from 5 and 7.

  12. THE IMPACT OF CONJUGATED LINOLEIC ACID ADDITION ON PH VALUE OF LONGISSIMUS DORSI MUSCLE

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    Przemysław WASILEWSKI

    2009-08-01

    Full Text Available The subject of research was 60 crossbred gilts, divided into 6 groups, fed the fodder with addition of conjugated linoleic acid (CLA or sunflower oil (SFO in amount: 0.5; 1.0; and 2.0 %, respectively. Animals were slaughtered with the body weight ca. 95 kg. The aim of research was to determine pH value of loin meat tissue (Longissimus dorsi of right half-carcass in 45 minutes, 2, 3, 4, 5, 6 hours and 24 hours after slaughter. Results were statistically elaborated using one-way variance analysis. Longissimus dorsi muscle pH values measured 45 minutes after slaughter in case of all groups of pigs were in range from 6.34 up to 6.47, what shows good meat quality. The lowest pH1 (measured 45 minutes after slaughter had meat of fatteners where addition of 2 % sunflower oil was given into fodder and the highest value of this trait was in group of individuals where also was given sunflower oil in 1 % amount. Statistical significant differences in pH value measured in different time after slaughter i.e. after 45 minutes, 2, 3, 4, 6 and 24 hours between tested groups of pigs were not stated. The exception is the result of pH measurement 5 hours after slaughter. Statistical significant differences were between group of pigs getting 0.5 % addition of conjugated linoleic acid characterized by the highest pH value of meat and group of animals fed the fodder with 1 % addition of conjugated linoleic acid (P≤0.01. On the basis of the results obtained in presented paper may be stated that feeding pigs with addition of conjugated linoleic acid in amounts 0.5; 1.0 and 2.0 % did not impact negatively on meat quality defined by pH value.

  13. Miscibility of Quillaja Saponins with other Co-surfactants under Different pH Values.

    Science.gov (United States)

    Reichert, Corina L; Salminen, Hanna; Leuenberger, Bruno H; Hinrichs, Jörg; Weiss, Jochen

    2015-11-01

    The miscibility behavior of mixed surfactant systems and the influence of extrinsic parameters are crucial for their application as emulsifiers. Therefore, the objective of this study was to evaluate the miscibility behavior of mixed systems composed of commercial Quillaja saponin and a co-surfactant, namely sodium caseinate, pea protein, rapeseed lecithin, or egg lecithin. These mixtures were evaluated macro- and microscopically at different concentration ratios (maximum concentration 5% w/v) at pH 3, 5, and 7 at 25 °C. The individual ingredients were also assessed for their charge properties and surface hydrophobicity. The results showed that Quillaja saponin-caseinate mixtures were miscible only at pH 7, and showed aggregation and precipitation at lower pH due to increasing electrostatic attraction forces. Rheological measurements showed that Quillaja saponin-pea protein mixtures formed gelled structures at all tested pH values mainly via association of hydrophobic patches. Quillaja saponins mixed with rapeseed lecithin were miscible at all tested pH values due to electrostatic repulsion. Quillaja saponin-egg lecithin mixtures aggregated independent of pH and concentration ratio. The microscopic analysis revealed that the lower the pH and the higher the Quillaja saponin ratio, the denser were the formed Quillaja saponin-egg lecithin aggregates. The results are summarized in ternary phase diagrams that provide a useful tool in selecting a surfactant system for food applications. © 2015 Institute of Food Technologists®

  14. Direct interaction between terbium ion and peroxidase in horseradish at different pH values.

    Science.gov (United States)

    Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2014-02-01

    Rare earth elements (REEs) entering plant cells can directly interact with peroxidase in plants, which is the structural basis for the decrease in the activity of peroxidase. Different cellular compartments have different pH values. However, little information is available regarding the direct interaction between REEs and peroxidase in plants at different pH values. Here, we investigated the charge distribution on the surface of horseradish peroxidase (HRP) molecule as well as the interaction of terbium ion (Tb(3+), one type of REEs) and HRP at different pH values. Using the molecular dynamics simulation, we found that when the pH value was from 4.0 to 8.0, a large amount of negative charges were intensively distributed on the surface of HRP molecule, and thus, we speculated that Tb(3+) with positive charges might directly interact with HRP at pH 4.0-8.0. Subsequently, using ultraviolet-visible spectroscopy, we demonstrated that Tb(3+) could directly interact with HRP in the simulated physiological solution at pH 7.0 and did not interact with HRP in other solutions at pH 5.0, pH 6.0 and pH 8.0. In conclusion, we showed that the direct interaction between Tb(3+) and HRP molecule depended on the pH value of cellular compartments.

  15. Composition of calcium phosphates precipitated from aqueous solutions at different pH values

    Energy Technology Data Exchange (ETDEWEB)

    Salahi, E.; Moztarzadeh, F. [Ceramics Div., Teheran (Iran). Materials and Energy Research Center

    2001-03-01

    During the preparation of calcium phosphate compounds by precipitation from aqueous solutions, several phases, namely dicalcium hydrogen phosphate (DCP, CaHPO{sub 4}), dicalcium hydrogen phosphate dihydrate DCPD, CaHPO{sub 4} (2 H{sub 2}O), hydrated calcium phosphate Ca{sub 3}(PO){sub 4} 2(H{sub 2}O) and hydroxyapatite (HAp, Ca10(PO{sub 4})6(OH){sub 2}), can be formed at different pH values. In the research work presented here, Ca(NO{sub 3})2(4H{sub 2}O) and (NH{sub 4})2HPO{sub 4} were used as starting materials The two solutions with an initial molar ratio of Ca/P=1,67 were mixed at 20 C at 0<pH<13. The resulting precipitates were studied by means of X-ray diffraction, infrared spectroscopy and inductively coupled plasma techniques, before and after heating at 1100 C for 1 h. When the pH of the products are plotted against the pH of the reacting solutions, four pH regions can be distinguished: at pH<4, there is no precipitate, while between 4 and 8, DCP, DCPD and hydrated calcium phosphate are formed. A structural transition was observed at 8<pH<10, and finally hydroxyapatite is formed at higher pH values. In the heated precipitates, {beta}-Ca{sub 2}P{sub 2}O{sub 7} developed at pH 6..7, this phase became well crystallized; at pH 7..8, {beta}-tricalcium phosphate ({beta}-TCP,Ca{sub 3}(PO{sub 4}){sub 2}) developed. Between pH 8 and 9, this phase could be observed clearly. At pH 9..10, there is a transitional state, and at pH >10,5, the hydroxyapatite was developed completely. (orig.)

  16. [Advances in the effects of pH value of micro-environment on wound healing].

    Science.gov (United States)

    Tian, Ruirui; Li, Na; Wei, Li

    2016-04-01

    Wound healing is a complex regeneration process, which is affected by lots of endogenous and exogenous factors. Researches have confirmed that acid environment could prevent wound infection and accelerate wound healing by inhibiting bacteria proliferation, promoting oxygen release, affecting keratinocyte proliferation and migration, etc. In this article, we review the literature to identify the potential relationship between the pH value of wound micro-environment and the progress of wound healing, and summarize the clinical application of variation of pH value of micro-environment in wound healing, thereby to provide new treatment strategy for wound healing.

  17. Influence of pH value on Cu (II biosorption by lignocellulose peach shell waste material

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    Lopičić Zorica R.

    2013-01-01

    Full Text Available In the last decade, the pollution made by anthropogenic sources has reached large amounts with special attention on heavy metals because of their high toxicity, persistence and bioaccumulation tendency. Since the conventional methods for their removing are either too expensive or create large quantities of toxic sludge, the great attention has been paid to the new technologies such as biosorption, technology that use cheap, abundant, organic waste for sequestering pollutants from contaminated mediums. Among the other factors that affect biosorption process, pH value is one the most important because it directs both the metal solution chemistry as well as the activity of the biomass functional groups. In this paper the influence of pH value on biosorption of Cu (II by unmodified low-cost lignocellulose biosorbent - peach shell (PS particles, have been studied. The chemical composition of PS, point of zero charge (pHPZC as well as its surface morphology is also presented. Results have showed that this biosorbent contains mainly cellulose and lignin, the components that carry the functional groups responsible for metal binding. Its multilayer surface contains many pores and channels that help diffusion in deeper layers and force biosorption process. Point of zero charge determination was performed with three different KNO3 ionic strengths: 0,1M, 0,01M and 0,001M. The obtained value for pHPZC was 4,75±0,1 and showed that this biosorbent is non-sensitive to ionic strength of electrolyte applied. Biosorption experiments were done with peach shell particles whose diameter was -0,5+0,1mm at 25oC . The initial copper (II concentration was 50 mg/dm3 while the biosorbent concentration was 10g/dm3. Experiments were done with and without keeping pH constant. The influence of pH on biosorption process was examined in 2-6 pH range. The percentage of Cu (II removed by PS, reaches its maximum at pH 6, with the 90,43% removing but this percentage can also be

  18. Determination of the Ph &Turbidity Value in Betul Block Five Year

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    Ravi Kumar

    2016-07-01

    Full Text Available Acidic and basic are two extremes that describe chemicals, just like hot and cold are two extremes that describe temperature. Mixing acids and bases can cancel out their extreme effects; much like mixing hot and cold water can even out the water temperature. A substance that is neither acidic nor basic is neutral. The ph of the water in betul block is increasing year by year and day by day. It was observed that there are 0.5% increase in the ph of water in betul block. The optimum pH will vary in different supplies according to the composition of the water and the nature of the construction materials used in the distribution system, but is often in the range 6.5–9.5. Extreme pH values can result from accidental spills, treatment breakdowns, and insufficiently cured cement mortar pipe linings. No health-based guideline value is proposed for pH.

  19. [Investigation of apomyoglobin stability depending on urea and temperature at two different pH values].

    Science.gov (United States)

    Baryshnikova, E N; Sharanov, M G; Kashparov, I A; Il'ina, N B; Bychkova, V E

    2005-01-01

    Equilibrium unfolding of apomyoglobin by urea was investigated in the temperature range from 5 to 25 degrees C at two pH values. The thermodynamic parameters of the apomyoglobin native-unfolded state transition were determined. Conformational changes in the protein structure were monitored by tryptophan fluorescence and far UV circular dichroism. Apomyoglobin preserves its native conformation at pH 5.7 and 6.2 in the temperature range used. It was shown that the apomyoglobin stability and its unfolding cooperativity are substantially lower at 5 degrees C than at other temperatures. This fact should be taken in account at the investigation of apomyoglobin.

  20. Improvement of physicomechanical properties of carbamazepine by recrystallization at different pH values.

    Science.gov (United States)

    Javadzadeh, Yousef; Mohammadi, Ameneh; Khoei, Nazaninossadat Seyed; Nokhodchi, Ali

    2009-06-01

    The morphology of crystals has an appreciable impact role on the physicochemical properties of drugs. Drug properties such as flowability, dissolution, hardness and bioavailability may be affected by crystallinity behaviours of drugs. The objective of this study was to achieve an improved physicomechanical property of carbamazepine powder through recrystallization from aqueous solutions at different pH values. For this purpose, carbamazapine was recrystallized from aqueous solutions at different pH values (1, 7, 11). The morphology of crystals was investigated using scanning electron microscopy; X-ray powder diffraction (XRPD) was used to identify polymorphism; thermodynamic properties were analyzed using differential scanning calorimetery (DSC). Dissolution rate was determined using USP dissolution apparatus. Mechanical behavior of recrystallized carbamazepine powders was investigated by making tablets under different compaction pressure and measuring their hardness. SEM studies showed that the carbamazepine crystallization in different media affected the morphology and size of carbamazepine crystals. The shape of carbamazepine crystals changed from flaky or thin plate-like to needle shape. XRPD and DSC results ruled out any crystallinity changes occurring due to the temperature during recrystallization procedure or pH of crystallization media. The crushing strength of tablets indicated that all of the recrystallized carbamazepine samples had better compactiblity than the original carbamazepine powder. In vitro dissolution studies of carbamazepine samples showed a higher dissolution rate for carbamazepine crystals obtained from media with pH 11 and 1. Carbamazepine particles recrystallized from aqueous solutions of different pH values (all media) appeared to have superior mechanical properties to those of the original carbamazepine sample.

  1. Comparison among Different pH Values of Rhodamine B Solution Impregnated into Mesoporous Silica

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    Juliana Jorge

    2013-05-01

    Full Text Available We studied the behavior of different pH values of Rhodamine B solution impregnated into pores of mesoporous silica, through structural characterization techniques, such as scanning electron microscopy and porosity measurements, and spectroscopic characterization techniques, such as infrared and luminescence spectroscopy; in order to applications in luminescence. Because, Rhodamine B is an interesting xanthene dye whose optical properties depend of many factors, dye concentration and pH values. MSU-4 type mesoporous silica has been synthesized with Tween 60 surfactant as directing-structure agent and tetraethyl orthosilicate (Si(OEt4, TEOS as silica source. The mesoporous structures doped with dyes are promissory materials for several applications, for example, optical sensors and biomarkers.

  2. Chloride content and pH value in the pore solution of concrete under carbonation

    Institute of Scientific and Technical Information of China (English)

    Xiao-mei WAN; Folker H.WITTMANN; Tie-jun ZHAO; Hong FAN

    2013-01-01

    Chloride content and the pH value of the pore solution in the neighborhood of steel reinforcement are decisive parameters for initiation and rate of corrosion.The pore solution of cement mortar and hardened cement paste has been expressed from the pore space by high pressure in the investigation.The influence of the water-cement ratio,age,and addition of chloride to the fresh mix on chloride content in the pore solution has been determined by ion chromatography.At the same time the pH value of the pore solution has been determined.The dissolved chloride content decreases with increase in the water-cement ratio.The amount of bound chloride increases with time,but it decreases with decreasing content of dissolved chloride in the pore solution.A significant influence of carbonation on the dissolved chloride content of the pore solution has been observed.With complete carbonation,the dissolved chloride content in cement mortar and hardened cement paste increases by a factor between 2 and 12.The bound chloride decreases by 27%-54%.As expected,the pH value decreases from around 13.2 to as low as 8.0 due to carbonation.It can be concluded that carbonation not only lowers the pH value but liberates bound chloride.This is one obvious reason why the combined action of chloride penetration and carbonation accelerates steel corrosion and shortens the service life of reinforced concrete structures.

  3. Effects of pH value and coagulant dosage on contact filtration of humic substances

    Institute of Scientific and Technical Information of China (English)

    蒋绍阶; 刘宗源; 梁建军

    2009-01-01

    Humic substances (especially fulvic acid (FA)) are the major components of natural organic matter (NOM) that widely exist in drinking water source. Due to their potential effects on public health,the removal of FA was one of the main concerns during the water treatment. Therefore,the contact filtration of FA by using aluminum sulfate as coagulant on the basis of jar tests was carried out. The effects of pH and coagulant dosage on the FA removal and the development of head loss were investigated. The results show that the range of pH value during the FA contact filtration can be effectively influenced by the dosage of aluminum sulfate,and the high aluminum sulfate dosage is an important factor that can result in early filter breakthrough. The FA filtration by deep-bed filtration or by membrane filtration is sometimes disparate under the same coagulation conditions. The choice of aluminum sulfate dosage by the method of membrane filtration,i.e. the "true color measurement",may result in inappropriate filter run,whereas it can be determined with simple jar tests by observing the formation of micro flocs. Considering the effects of pH on aluminum sulfate dosage and FA removal,the optimal pH range of 5.5?6.0 is suggested.

  4. COLOUR AND pH VALUE OF ISTRIAN SHEEP LAMBS MEAT

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    Valentino Držaić

    2016-06-01

    Full Text Available The aim of the present study was to evaluate the effect of sex and slaughter weight of Istrian sheep lambs on pH value and meat colour. The study included 118 lambs of both sexes (64 male and 54 female which were, prior slaughter, divided into two groups: light (17.76 kg; 28 male and 32 female and heavy (20.17 kg; 3 male and 22 female. Carcass weight was determined immediately after carcass processing and after 24 hours, while the pH value and meat colour were determined 45 minutes and 24 hours after slaughter. Average hot and cold carcass weights in light lambs were 9.76 and 9.47 kg, and in heavy lambs 11.80 and 11.49 kg, with chilling loss of 2.96 and 2.60% respectively. Istrian sheep lambs carcasses are quite uniform in relation to sex in terms of all the investigated traits, except value of L* and a* colour parameters. For the production of larger lamb meat quantities it might be recommended to increase lambs slaughter weight since the higher slaughter weight has the positive effect on carcass weight and chilling loss while retaining the desirable values of meat quality parameters.

  5. Predictive value of gastric intramucosal pH for critical patients

    Institute of Scientific and Technical Information of China (English)

    Hong Tao; Bing Wen Jing; Shu Zhen Li; Xiang Yu Zhang

    2000-01-01

    AIM To observe the predictive value of gastric intramucosal pH (pHi) for critical patients.METHODS The gastric intramucosal pH (pHi) of 32 ICU patients was measured with a self-madegastrointestinal tonometer, and the APACHE l score was determined simultaneously.RESULTS pHi of the nonsurvivors was significantly lower than that of the survivors (P<0.05). The pHiwas remarkably higher in the nonsepsis group than in the sepsis group (P<0.01). Only in multiple organfailure groups, pHi was found statistically lower (P<0.05).CONCLUSION pHi may be the most simple, reliable, sensitive and accurate parameter to indicate theadequacy of tissue oxygenation, and it may be widely used in ICU monitoring in near future.

  6. 食品的 pH 值与微生物控制%PH value and microbial control of food

    Institute of Scientific and Technical Information of China (English)

    赵君哲

    2015-01-01

    介绍了食品中 pH 值对微生物的影响;酸性食品与低酸性食品的不同,以及对微生物控制的操作差异。%The effect of the pH value of food on microbial was introduced. The difference of acid food and low acidity food and the different operation of microbial control were studied.

  7. Micro Electrochemical pH Sensor Applicable for Real-Time Ratiometric Monitoring of pH Values in Rat Brains.

    Science.gov (United States)

    Zhou, Jie; Zhang, Limin; Tian, Yang

    2016-02-16

    To develop in vivo monitoring meter for pH measurements is still the bottleneck for understanding the role of pH plays in the brain diseases. In this work, a selective and sensitive electrochemical pH meter was developed for real-time ratiometric monitoring of pH in different regions of rat brains upon ischemia. First, 1,2-naphthoquinone (1,2-NQ) was employed and optimized as a selective pH recognition element to establish a 2H(+)/2e(-) approach over a wide range of pH from 5.8 to 8.0. The pH meter demonstrated remarkable selectivity toward pH detection against metal ions, amino acids, reactive oxygen species, and other biological species in the brain. Meanwhile, an inner reference, 6-(ferrocenyl)hexanethiol (FcHT), was selected as a built-in correction to avoid the environmental effect through coimmobilization with 1,2-NQ. In addition, three-dimensional gold nanoleaves were electrodeposited onto the electrode surface to amplify the signal by ∼4.0-fold and the measurement was achieved down to 0.07 pH. Finally, combined with the microelectrode technique, the microelectrochemical pH meter was directly implanted into brain regions including the striatum, hippocampus, and cortex and successfully applied in real-time monitoring of pH values in these regions of brain followed by global cerebral ischemia. The results demonstrated that pH values were estimated to 7.21 ± 0.05, 7.13 ± 0.09, and 7.27 ± 0.06 in the striatum, hippocampus, and cortex in the rat brains, respectively, in normal conditions. However, pH decreased to 6.75 ± 0.07 and 6.52 ± 0.03 in the striatum and hippocampus, upon global cerebral ischemia, while a negligible pH change was obtained in the cortex.

  8. A note on stereological estimation of the volume-weighted second moment of particle volume

    DEFF Research Database (Denmark)

    Jensen, E B; Sørensen, Flemming Brandt

    1991-01-01

    It is shown that for a variety of biological particle shapes, the volume-weighted second moment of particle volume can be estimated stereologically using only the areas of particle transects, which can be estimated manually by point-counting.......It is shown that for a variety of biological particle shapes, the volume-weighted second moment of particle volume can be estimated stereologically using only the areas of particle transects, which can be estimated manually by point-counting....

  9. Effect of pH value on electromagnetic loss properties of Co–Zn ferrite prepared via coprecipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaogu, E-mail: nthxg@126.com [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044 (China); School of Material Science and Engineering, Georgia Institute of Technology, Atlanta 30332 (United States); Zhang, Jing [Nanjing Center, China Geological Survey, Nanjing 210016 (China); Wang, Wei [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Sang, Tianyi [Department of Electrical and Computer Engineering, University of California Davis, Davis 95616 (United States); Song, Bo [School of Material Science and Engineering, Georgia Institute of Technology, Atlanta 30332 (United States); Zhu, Hongli [Institute 53 of China North Industries Group Corporation, Jinan 250031 (China); Rao, Weifeng [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science & Technology, Nanjing 210044 (China); Wong, Chingping [School of Material Science and Engineering, Georgia Institute of Technology, Atlanta 30332 (United States)

    2016-05-01

    In this paper, the cobalt zinc ferrite was prepared by coprecipitation method at different pH conditions. The influence of pH values on the coprecipitation reaction was theoretically analyzed at first. The calculated results showed that the pH values should be controlled in the range of 9–11 to form the stable precipitation. The XRD investigation was used to further confirm the formation of the composite on specific pH values. In addition, the morphological study revealed that the average particle size of the composite decreased from 40 nm to 30 nm when the pH value increased from 9–11. The variation of microstructure plays a critical role in controlling the electromagnetic properties. From the electromagnetic analysis, the dielectric loss factor was 0.02–0.07 and magnetic loss factor was 0.2–0.5 for the composite synthesized at pH of 9, which presents dramatically improved dielectric loss and magnetic loss properties than the samples prepared at pH of 10 and 11. The as-prepared cobalt zinc ferrite are highly promising to be used as microwave absorption materials. - Highlights: • Co–Zn ferrite was prepared by coprecipitation method with different pH values. • To obtain pure Co–Zn ferrite, the theoretical pH values were 9–11. • Microstructure and electromagnetic properties can be tuned by varying pH values. • Co–Zn ferrite prepared with pH=9 performed well electromagnetic loss properties.

  10. Effect of pH values on the extracellular polysaccharide secreted by Acidithiobacillus ferrooxidans during chalcopyrite bioleaching

    Institute of Scientific and Technical Information of China (English)

    Run-lan Yu; Jing Liu; Jian-xi Tan; Wei-min Zeng; Li-juan Shi; Guo-hua Gu; Wen-qing Qin; Guan-zhou Qiu

    2014-01-01

    The pH value plays an important role in the bioleaching of sulphide minerals. The effect of pH values on the extracellular poly-saccharide secreted by Acidithiobacillus ferrooxidans was investigated in different phases of bacterial growth during chalcopyrite bioleach-ing. It is found that extracellular polysaccharide secretion from the cells attached to chalcopyrite is more efficiently than that of the free cells in the bioleaching solution. Three factors, pH values, the concentration of soluble metal ions, and the bacterial growth and metabolism, affect extracellular polysaccharide secretion in the free cells, and are related to the bacterial growth phase. Extracellular polysaccharide secretion from the attached cells is mainly dependent on the pH value of the bacterial culture.

  11. Effect of pH value on electromagnetic loss properties of Co-Zn ferrite prepared via coprecipitation method

    Science.gov (United States)

    Huang, Xiaogu; Zhang, Jing; Wang, Wei; Sang, Tianyi; Song, Bo; Zhu, Hongli; Rao, Weifeng; Wong, Chingping

    2016-05-01

    In this paper, the cobalt zinc ferrite was prepared by coprecipitation method at different pH conditions. The influence of pH values on the coprecipitation reaction was theoretically analyzed at first. The calculated results showed that the pH values should be controlled in the range of 9-11 to form the stable precipitation. The XRD investigation was used to further confirm the formation of the composite on specific pH values. In addition, the morphological study revealed that the average particle size of the composite decreased from 40 nm to 30 nm when the pH value increased from 9-11. The variation of microstructure plays a critical role in controlling the electromagnetic properties. From the electromagnetic analysis, the dielectric loss factor was 0.02-0.07 and magnetic loss factor was 0.2-0.5 for the composite synthesized at pH of 9, which presents dramatically improved dielectric loss and magnetic loss properties than the samples prepared at pH of 10 and 11. The as-prepared cobalt zinc ferrite are highly promising to be used as microwave absorption materials.

  12. Study on Impacts of pH Value on Paulownia Wood Color

    Institute of Scientific and Technical Information of China (English)

    CHANG Delong; SONG Zhanqian; HU Weihua; HUANG Wenhao; LI Fuhai; ZHANG Yunling

    2006-01-01

    Impacts of acid and alkali on paulownia wood are studied, and the effects of weak alkali solution on stain prevention of paulownia wood are tested and analyzed. It shows that pH value affects paulownia wood color, and that white value of paulownia wood is prone to decrease and chromatism rises under acidity condition. Under alkalescence condition, whiteness of paulownia wood rises and chromatism decreases, color and luster obviously tend to be bright. The alkali solution with concentration of 0.25% can promote the penetrability of paulownia wood, dissolve some extractives containing stain precursor chemicals, strengthen stain prevention of paulownia wood, but can not contaminate board surface. Anti-stain reagent has effect on prevention stain of paulownia wood, but only using it for controlling paulownia wood stain will induce stain-returning phenomenon. Using both weak alkali solution and anti-stain reagent has better effect than just using reagent, the treatment by concentration of 0.25% weak alkali solution with anti-stain reagent can make controlling effect even both inside and outside.

  13. Electrochemical performance of nano-scale β-Ni(OH)2 prepared at different transformations of pH value

    Institute of Scientific and Technical Information of China (English)

    ZHAO Li; ZHANG Li-jun; HAN Xi-jiang; ZHANG Cui-fen

    2008-01-01

    The influence of transforming pH values on the electrochemical performance of nano-scale Ni(OH)2was analyzed. The measurement results of XRD indicate that the nano-scale Ni (OH)2 prepared at different transformations of pH value is β( Ⅱ )-phase with different crystal lattice parameters. Cyclic voltammograms (CV) and electrochemical impedance spectroscopy(EIS) measurement results show that transformations of pH value affect the proton diffusion coefficient (D) and charge-transfer resistance (Rct) of the material. The simu-lation of cell experiment shows that the sample prepared at a pH of 10. 1 exhibits the maximum specific capacity(327. 8 mAh/g) and higher discharge platform, the discharge performance of electrodes depends on both D and Rct, so the kinetics characteristics that electrodes reaction is controlled by both mass-transfer step and charge-transfer step are put forward.

  14. Tolerance of Physocypria kraepelini (Crustacean, Ostracoda) to water-borne ammonia, phosphate and pH value

    Institute of Scientific and Technical Information of China (English)

    YU Na; CHEN Shimei; LI Erchao; CHEN Jiayan; CHEN Liqiao

    2009-01-01

    This study evaluated the median lethal concentration (LC_(50)) and safe concentration of water-borne ammonia,phosphate and pH value on Physocypria kraepelini,a freshwater Ostracoda with a static renewal test system.The results indicated that the LC_(50) values of ammonia for P.kraepelini were 1026.71,859.98,771.79 and 583.82 mg/L at 24,48,72 and 96 h exposure,respectively,and the safe concentration range of ammonia for the long-term survival of P.kraepelini was less than 58.38 mg/L.Finally,the safe range of pH value for the survival of P.kraepelini was from 6.59 to 7.61.P.kraepelini has a high tolerance to ammonia,phosphate and pH value which are the main environmental factors in the serious eutrophication water.

  15. Hydrogel/fiber optic sensor for distributed measurement of humidity and pH value

    Science.gov (United States)

    MacLean, Alistair; Michie, W. Craig; Pierce, S. Gareth; Thursby, Graham; Culshaw, Brian; Moran, Chris; Graham, Neil B.

    1998-07-01

    The combination of chemically sensitive, swellable polymer materials with novel optical fiber cable designs to transduce the swelling activity into microbend loss enables a simple yet powerful sensor to be produced. Interrogating such cables with standard optical time domain reflectoctrometry (OTDR) instruments allows particular chemicals of interest to be detected and located along a cable which may extend to several kilometers. We report here on a sensor cable which uses a water swellable material, a hydrogel, to detect positions of water ingress, relative humidity level or pH value. In direct water ingress tests, wet sensor lengths as small as 5 cm in several hundreds of meters have been detected using conventional OTDRs. Following a review of the sensor design, we present the results of an investigation of the mechanical interaction between the hydrogel polymer and the optical fiber within the sensor. The behavior of the sensor is then characterized within environments of different relative humidity levels from 70 percent to 100 percent at temperatures ranging from 0 to 60 degrees C. The sensor was initially designed for applications within civil engineering but can be applied to a much broader range of measurement requirements, for example soil moisture measurement. We will report details on experimental observations on concrete cure within reinforcing tendon ducts and soil humidity measurements within different soil types.

  16. Path Integral for Stochastic Inflation: Non-Perturbative Volume Weighting, Complex Histories, Initial Conditions and the End of Inflation

    CERN Document Server

    Gratton, Steven

    2010-01-01

    In this paper we present a path integral formulation of stochastic inflation, in which volume weighting can easily be implemented. With an in-depth study of inflation in a quartic potential, we investigate how the inflaton evolves and how inflation typically ends both with and without volume weighting. Perhaps unexpectedly, complex histories sometimes emerge with volume weighting. The reward for this excursion into the complex plane is an insight into how volume-weighted inflation both loses memory of initial conditions and ends via slow-roll. The slow-roll end of inflation mitigates certain "Youngness Paradox"-type criticisms of the volume-weighted paradigm. Thus it is perhaps time to rehabilitate proper time volume weighting as a viable measure for answering at least some interesting cosmological questions.

  17. Effect of pH Value on Stress Corrosion Cracking of X70 Pipeline Steel in Acidic Soil Environment

    Institute of Scientific and Technical Information of China (English)

    Zhiyong LIU; Cuiwei DU; Xin ZHANG; Fuming WANG; Xiaogang LI

    2013-01-01

    The effect of pH value on the stress corrosion cracking (SCC) of API X70 pipeline steel in simulated acidic soil solutions was investigated by using slow strain rate test,electrochemical polarization curves,electrochemical impedance spectroscopy,and scanning electron microscopy.pH plays an important role in the susceptibility and electrochemical mechanism of SCC.The pH higher than 5 has no significant effect on electrochemical processes.By contrast,the pH lower than 5 intensifies cathodic hydrogen evolution reactions,thus increasing the cathodic current and corrosion potential.Under different pH values,the SCC mechanism of X70 pipeline steel varies among anodic dissolution (AD),hydrogen embrittlement (HE),and the combination of AD and HE (AD + HE) with variations of applied potential.At-850 mVSCE,the SCC mechanism is HE if pH is less than 4 or AD + HE if pH value is more positive.

  18. Haptic Illusions: Biases in the perception of volume, weight and roughness

    NARCIS (Netherlands)

    Kahrimanovic, M.

    2011-01-01

    The present thesis investigated the perception of volume, weight and roughness when exploring 3-dimensional objects by touch and/of vision, and examined whether these percepts were influenced by specific object properties (e.g shape, material). In perception research, the term bias has been used to

  19. Investigations into aggregate formation with oppositely charged oil-in-water emulsions at different pH values.

    Science.gov (United States)

    Maier, Christiane; Zeeb, Benjamin; Weiss, Jochen

    2014-05-01

    The pH-dependent formation and stability of food-grade heteroaggregates from oppositely charged oil-in-water (O/W) emulsions was investigated. After screening suitable emulsifiers, 10% (w/w) oil in-water emulsions (d32≈1 μm) were prepared at pH 3-7 using a positively charged emulsifier (Na-lauroyl-l-arginine ethyl ester; LAE) and four negatively charged ones (citric esters of mono- and diglycerides, soy lecithin, sugar beet pectin, and Quillaja saponin). The oppositely charged emulsions were then combined at constant pH values at a volume flow rate ratio of 1:1. Emulsions and heteroaggregates were characterized by their surface charge, particle size distribution and microstructure using dynamic and static light scattering as well as confocal laser scanning microscopy. The emulsifier type was found to greatly influence the type of heteroaggregates formed, as well as the pH value, specifically in combined LAE/Quillaja saponin emulsions. Larger aggregates particularly were formed with increasing pH values (2.71±1.21 to 46.53±4.30 μm from pH 3 to 7, respectively), while LAE/pectin aggregates appeared not to be affected by pH over the full pH range investigated (3.80±2.89 to 3.94±2.78 μm from pH 3 to 7, respectively). Our study thus provides valuable first insights into the mechanism of the formation of food-grade heteroaggregates for later use in food systems. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. THE RESULTS OF EXPERIMENTAL RESEARCH OF INFLUENCE OF ACOUSTIC AND MAGNETIC FIELD ON ELECTROCONDUCTIVITY AND PH VALUE OF HYDROPONIC SOLUTION

    Directory of Open Access Journals (Sweden)

    Korzhakov A. V.

    2015-06-01

    Full Text Available The article deals with the results of research of acoustic and magnetic field influence on conductivity and pH value of hydroponic solution. For carrying out researches in this area the hypothesis of possibility of nutrient solution influence on ions by means of an acoustic and magnetic field is set up. A laboratory scale plant was constructed for a pilot study of the hypothesis. The solution was moved in the tube passing through a ferrite ring with winding. Thus, the solution was exposed to the influence of acoustic and magnetic field. The object of research was hydroponic solution of (NH42SO4; (NH42HPO4; K2SO4; Ca(NO32; MgSO4 in water having adjusted concentration and acidity. The solution was taken from the tank of laboratory scale plant by means of the pump, passed through the working area of the acoustic and magnetic device, filter, and then was poured into the tank, from which the sample for pH level changing was taken. The pH value was measured at the temperature of 22С by using electronic pH-meter KL-009(1A. For control of instrument readings acidity was tested by universal test-paper. The initial pH value of solution made 5. As a result of acoustic and magnetic treatment of solution pH value of hydroponic solution increased from 6 to 6.9. The results show the possibility of pH value correction by small energy input

  1. Effects of pH values on the properties of buffalo and cow butter-based low-fat spreads

    Directory of Open Access Journals (Sweden)

    Abdeldaiem, A. M.

    2014-09-01

    Full Text Available The objective of this study was to characterize the effects of pH values (5, 5.5, 6, 6.5 and 7 on the properties of buffalo and cow butter-based low-fat spreads. Sensory evaluation of the samples decreased with an increase in pH values and during the storage periods. In addition, phase separation occurred with pH 6, 6.5 and 7. The differences in peroxide values and oil stability index among the samples compared to the control samples were slight, while peroxide values and oil stability index decreased during the storage periods. Changes in fatty acid composition among the pH treatments and during the storage periods were detected. Differences in solid fat contents among pH treatments separately and during the storage periods were negligible. A decline in the hardness and viscosity of the samples were accompanied by an increase in pH values, and the treatments had increased effects during the storage periods. Generally, an increase of pH values did not affect the melting profiles of the spreads. Additionally, changes between the melting profiles of buffalo and cow butter-based low-fat spreads were detected.El objetivo fue determinar los efectos del pH (5, 5.5, 6, 6.5 y 7 en las propiedades de mantequillas para untar bajas en grasa de búfalos y vacas. La puntuación sensorial de las muestras disminuyó con el aumento del pH y durante los períodos de almacenamiento, además, la separación de fases se produjo con pH de 6, 6,5 y 7. Se observaron diferencias en los valores de peróxido e índice de estabilidad de la grasa de las muestras en comparación con las muestras control, mientras que los valores de peróxido incrementaron, el índice de estabilidad de la grasa disminuyó durante los períodos de almacenamiento. Se observan cambios en la composición de ácidos grasos entre los tratamientos de pH y durante los períodos de almacenamiento. Las diferencias en el contenido de grasa sólida entre los tratamientos de pH por separado y durante los

  2. [Reduction of nitrobenzene by iron oxides bound Fe(II) system at different pH values].

    Science.gov (United States)

    Luan, Fu-Bo; Xie, Li; Li, Jun; Zhou, Qi

    2009-07-15

    Batch tests were conducted to investigate the reductive transformation of nitrobenzene by goethite, hematite, magnetite and steel converter slag bound Fe(II) system. And the reduction mechanism was explored at different pH values. Experimental results showed that hematite, magnetite and steel converter slag could adsorb Fe(II) on surfaces and form iron oxides bound Fe(II) system at pH from 6.5 to 7.0. The systems had strong reductive capacity and could reduce nitrobenzene to aniline. The reduction efficiency of nitrobenzene in surface bound Fe(II) system followed the sequence of magnetite, hematite and steel converter slag from high to low. The reduction efficiency of hematite and magnetite system increased with pH increasing. While it was almost pH independent in steel converter slag system. Although goethite adsorbed most of Fe(II) in solution, the adsorbed Fe(II) had no reductive activity for nitrobenzene. At pH 6.0, small amount of Fe(II) was adsorbed on magnetite and hematite and the systems did not show reductive activity for nitrobenzene. However, steel converter slag could adsorb Fe(II) at pH 6.0 and reduction efficiency almost equaled to the value at pH 7.0. When pH was above 7.5, dissolved Fe(II) could be converted to Fe(OH)2 and the newly formed Fe(OH)2 became the main redactor in the system. Under alkali condition, the presence of iron oxides inhibited the reduction capacity of system.

  3. Estimation of water activity from pH and °Brix values of some food products.

    Science.gov (United States)

    Gabriel, Alonzo A

    2008-06-01

    In this study, a predictive model for the estimation of water activity (aw(25°C)) as a function of pH (1.00-8.00) and °Brix (0-82.00) values of simulated food solutions (SFS) was developed, through response surface methodology. Response fit analyses resulted in a highly significant (pHBrix values within the defined variable ranges. The linear, quadratic and interactive influences of pH and °Brix on aw(25°C) were all significant (pH<0.0001). Model validations in SFS and in a number of actual food systems showed that the model had acceptable predictive performance, as indicated by the calculated accuracy and bias indices.

  4. Study on the pH Value Control Method%pH值控制方法的研究

    Institute of Scientific and Technical Information of China (English)

    郭红霞; 刘磊

    2012-01-01

    由于pH过程的非线性和滞后性,pH值的检测和控制在化工生产过程中并非易事,本文主要分析了pH值曲线的非线性特点,应用分段式变增益PID的处理方法,提出了pH过程的分段式变增益PID控制设计方法,设计了一种分段式变增益PID控制算法,利用MATLAB仿真技术对pH值控制系统进行了仿真研究并与常规的PID控制算法进行了仿真对比,有效的实现了对pH值的控制.%Due to nonlinear and hysteresis quality of pH process, detection and control of pH value is not easy in chemical production process. This paper mainly analyzed the nonlinear features of pH value curve, applied the processing method of segment type variable gain PID, made the segment type variable gain PID control design method of pH process, designed a segment type variable gain PID control algorithm, used MATLAB simulation technology to make simulation research on pH value control system and made simulation comparison to the general PID control algorithm. At last the control of the pH value is effectively implemented.

  5. Uranium fate in wetland mesocosms: Effects of plants at two iron loadings with different pH values

    Science.gov (United States)

    Small-scale continuous flow wetland mesocosms (~0.8 L) were used to evaluate how plant roots under different iron loadings affect uranium (U) mobility. When significant concentrations of ferrous iron (Fe) were present at circumneutral pH values, U concentrations in root exposed ...

  6. Technical description of parameters influencing the pH value of suspension absorbent used in flue gas desulfurization systems.

    Science.gov (United States)

    Głomba, Michał

    2010-08-01

    As a result of the large limestone deposits available in Poland, the low cost of reagent acquisition for the largescale technological use and relatively well-documented processes of flue gas desulfurization (FGD) technologies based on limestone sorbent slurry, wet scrubbing desulfurization is a method of choice in Poland for flue gas treatment in energy production facilities, including power plants and industrial systems. The efficiency of FGD using the above method depends on several technological and kinetic parameters, particularly on the pH value of the sorbent (i.e., ground limestone suspended in water). Consequently, many studies in Poland and abroad address the impact of various parameters on the pH value of the sorbent suspension, such as the average diameter of sorbent particles (related to the limestone pulverization degree), sorbent quality (in terms of pure calcium carbonate [CaCO3] content of the sorbent material), stoichiometric surfeit of CaCO3 in relation to sulfur dioxide (SO2) absorbed from flue gas circulating in the absorption node, time of absorption slurry retention in the absorber tank, chlorine ion concentration in sorbent slurry, and concentration of dissolved metal salts (Na, K, Mg, Fe, Al, and others). This study discusses the results of laboratory-scale tests conducted to establish the effect of the above parameters on the pH value of limestone slurry circulating in the SO2 absorption node. On the basis of the test results, a correlation equation was postulated to help maintain the desirable pH value at the design phase of the wet FGD process. The postulated equation displays good coincidence between calculated pH values and those obtained using laboratory measurements.

  7. Inhibition Effect of Glycerol on the Corrosion of Copper in NaCl Solutions at Different pH Values

    Directory of Open Access Journals (Sweden)

    Santos Lorenzo Chi-Ucán

    2014-01-01

    Full Text Available The inhibitory effect of glycerol on copper corrosion in aerated NaCl (0.5 M solutions at three pH values (4, 7, and 10 was evaluated. Inhibition efficiency was assessed with conventional electrochemical techniques: open circuit potential, potentiodynamic polarization, and electrochemical impedance analysis. Glycerol reduced the corrosion rate of copper in NaCl solutions. The best inhibition effect (η≈83% was produced in alkaline (pH 10 chloride media. This effect can be ascribed to increased viscosity and the presence of copper-glycerol complexes.

  8. Actin proteolysis during ripening of dry fermented sausages at different pH values.

    Science.gov (United States)

    Berardo, A; Devreese, B; De Maere, H; Stavropoulou, D A; Van Royen, G; Leroy, F; De Smet, S

    2017-04-15

    In dry fermented sausages, myofibrillar proteins undergo intense proteolysis generating small peptides and free amino acids that play a role in flavour generation. This study aimed to identify small peptides arising from actin proteolysis, as influenced by the type of processing. Two acidification profiles were imposed, in order to mimic the pH normally obtained in southern-type and northern-type dry fermented sausages. The identification of peptides was done by liquid chromatography coupled to mass spectrometry in a data-independent positive mode of acquisition (LC-MS(E)). During manufacturing of the dry fermented sausages, actin was highly proteolysed, especially in nine regions of the sequence. After fermentation, 52 and 42 actin-derived peptides were identified at high and low pH, respectively, which further increased to 66 and 144 peptides, respectively, at the end of ripening. Most peptides were released at the cleavage sites of cathepsins B and D, which thus play an important role.

  9. Influence of the pH value of anthocyanins on the electrical properties of dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Irén Juhász Junger

    2017-03-01

    Full Text Available In recent years the harvesting of renewable energies became of great importance. This led to a rapid development of dye-sensitized solar cells which can be produced from low-purity materials. The best electrical properties are provided by cells prepared using synthetical, ruthenium based dyes. Unfortunately, most of them are toxic and expensive. The anthocyanins extracted for example from hibiscus flowers yield a more cost-effective and eco-friendly alternative to toxic dyes, however, with a loss of solar cell efficiency. In this article the possibility of improvement of the conversion efficiency by modification of the pH value of the dye is investigated. By decrease of the pH value, an increase of efficiency by a factor of two was achieved.

  10. Influence of lactic acid bacteria, probiotic cultures and pH value in fermented yoghurt drink to sensory quality

    Directory of Open Access Journals (Sweden)

    Hana Šulcerová

    2009-01-01

    Full Text Available Nowadays, we can see on market mainly fermented milk products with addition of probiotic microorganisms, especially strains of Lactobacillus and Bifidobacterium. We can meet also other types of pro­bio­tic products. It is recommended to consume at least 100 grams of fermented milk products with mi­ni­mal concentration of 106 of probiotics in one gram or mililitr of product daily for reaching positive effect on men’s health. During fermentation of the carbohydrates, proteins and lipids are disunite and many of aromatic compounds ane compose. They give a typical sensory characteristic to fermented milk products. For quality and quantity level of probiotics, changes of pH value and sensory qua­li­ty of five kinds of fermented milk product Yoghurt Drink with different flavour were analyzed during the whole expiration period (28 days. Obtained results were statistically evaluated via the analysis of variance and the method of multiple comparison according to Tukey test (P < 0,010 and (P < 0,001. During the minimal endurance time lactic acid bacteria and Bifidobacterium sp. were evaluated and changes of descriptors and pH value were detected. Number of LAB was up to 107 CFU/ml in all samples during 28 days of analysis. Only at sample 2 the number of LAB was 106 CFU/ml. Bifidobacterium sp. grew about degree. The number of LAB and Bifidobacterium sp. of yoghurt drink correspond with public notice number 77/2003 Sb, LAB 107 nad Bifidobacterium sp. 106 KTJ / ml. During 28 days of storage the pH value decreased. The biggest pH drop was recorded between 21. and 28. days of sto­ra­ge in all samples. The beginning pH value was 4.03–4.07 and the final value was between 3.80–3.95.The results of sensory evaluation processed by analysis of dispersion according to type were statistically conlusive in descriptors thickness, texture, intensity of smell, pleasantness of taste and general impression. The results of sensory evaluation processed by

  11. Effect of pH values of two bleaching gels on enamel microhardness.

    Science.gov (United States)

    Araujo, Natalia Costa; da Costa Soares, Manuella Uilmann Silva; Nery, Marcela Maria; Sales, Wagno Silva; Gerbi, Marleny Elizabeth Martinez

    2013-07-01

    This study evaluated the influence of bleaching gel pH and the effect of remineralizing gels after bleaching in different time intervals. Sixty bovine incisors were divided into 2 groups (n = 30). Group 1 was bleached with a 35% hydrogen peroxide (HP) acid gel and Group 2 was bleached with a 35% HP neutral gel. Each group was then divided into 3 subgroups (n = 10) according to the post-bleaching treatment used: storage in artificial saliva, application of a fluoride gel, or application of a gel consisting of fluoride, potassium nitrate, and nanostructured calcium phosphate. Specimens were stored in artificial saliva, and enamel microhardness was evaluated at 24 hours and 15 days postbleaching. Vickers microhardness data were analyzed by means of 2-way ANOVA, with repeated measurements and Bonferroni's post-hoc test. Twenty-four hours after bleaching, no significant differences were found between the bleaching gels. At 15 days postbleaching, Group 2 samples demonstrated a significant reduction in microhardness. No significant differences were found between the remineralizing gels, though all of the postbleaching treatments after the use of 35% neutral gel were able to re-establish baseline microhardness. It was concluded that neutral bleaching gel significantly reduced enamel microhardness 15 days after bleaching and that the use of remineralizing gels did not significantly enhance the microhardness of bleached enamel. However, in clinical situations, the acquired enamel pellicle protects tooth surfaces, and postbleaching, decalcified enamel would undergo recalcification. This study indicates that it is important to consider the bleaching agent's pH and composition when treating patients with reduced salivary secretion.

  12. Environmental Scanning Electron Microscopy characterization of the adhesion of conidia from Penicillium expansum to cedar wood substrata at different pH values.

    Science.gov (United States)

    El Abed, Soumya; Ibnsouda, Saad Koraichi; Latrache, Hassan; Meftah, Hasna; Tahri, Nezha Joutey; Hamadi, Fatima

    2012-04-01

    Initial microbial adhesion to surfaces is a complicated process that is affected by a number of factors. An important property of a solution that may influence adhesion is pH. The surface properties of the cedar wood were characterized by the sessile drop technique. Moreover, the interfacial free energy of surface adhesion to the cedar wood was determined under pH values (2, 3, 5, 7, 9 and 11). The results showed that cedar wood examined at different pH levels could be considered hydrophobic ranged from Giwi = -13.1 mJ/m(2) to Giwi = -75 mJ/m(2). We noted that the electron-donor character of cedar wood was important at both basic and limit acidic conditions (pH 11 and pH 3) and it decreased at intermediate pH (pH 5). The cedar wood substratum presents a weak electron acceptor under various pH's. In addition, the adhesion of conidia from Penicilllium expansum to the cedar wood surfaces at different pH values (2, 3, 5, 7, 9 and 11) was investigated using Environmental Scanning Electron Microscopy and image analysis was assessed with the Mathlab(®) program. The data analysis showed that the conidia from P. expansum were strongly influenced by the pH. The maximum adhesion occurs in the pH 11 and pH 3 and decreased to 24% at pH 5.

  13. Evaluation of Thiol Raman Activities and pKa Values Using Internally Referenced Raman-Based pH Titration.

    Science.gov (United States)

    Suwandaratne, Nuwanthi; Hu, Juan; Siriwardana, Kumudu; Gadogbe, Manuel; Zhang, Dongmao

    2016-04-05

    Thiols, including organothiol and thiol-containing biomolecules, are among the most important classes of chemicals that are used broadly in organic synthesis, biological chemistry, and nanosciences. Thiol pKa values are key indicators of thiol reactivity and functionality. Reported herein is an internally referenced Raman-based pH titration method that enables reliable quantification of thiol pKa values for both mono- and dithiols in water. The degree of thiol ionization is monitored directly using the peak intensity of the S-H stretching feature in the 2600 cm(-1) region relative to an internal reference peak as a function of the titration solution's pH. The thiol pKa values and Raman activity relative to its internal reference were then determined by curve fitting the experimental data with equations derived on the basis of the Henderson-Hasselbalch equation. Using this Raman titration method, we determined for the first time the first and second thiol pKa values for 1,2-benzenedithiol in water. This Raman-based method is convenient to implement, and its underlying theory is easy to follow. It should therefore have broad application for thiol pKa determinations and verification.

  14. Microencapsulation of butyl stearate with melamine-formaldehyde resin: Effect of decreasing the pH value on the composition and thermal stability of microcapsules

    Directory of Open Access Journals (Sweden)

    M. Krajnc

    2012-10-01

    Full Text Available The object of this study was to investigate how different decreasing of pH regimes during microencapsulation process with melamine-formaldehyde (MF resin affects the composition, morphology and thermal stability of microcapsules containing a phase-change material (PCM. Technical butyl stearate was used as PCM. Microencapsulation was carried out at 70°C. For all experiments the starting pH value was 6.0. After one hour of microencapsulation at the starting pH value, the pH value was lowered to final pH value (5.5; 5.0; 4.5 in a stepwise or linear way. The properties of microcapsules were monitored during and after the microencapsulation process. The results showed that pH value decreasing regime was critical for the morphology and stability of microcapsules. During microencapsulations with a stepwise decrease of pH value we observed faster increase of the amount of MF resin in the microencapsulation product compared to the microencapsulations with a linear pH value decrease. However, faster deposition in the case of microencapsulations with stepwise decrease of pH value did not result in thicker MF shells. The shell thickness increased much faster when the pH value was decreased in a linear way or in several smaller steps. It was shown that for the best thermal stability of microcapsules, the pH value during microencapsulation had to be lowered in a linear way or in smaller steps to 5.0 or lower.

  15. Capacitance Characterization of the Effect of pH Value on the Self-assembled Monolayers of Octadecanethiol

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, the membrane capacitance (Cm), which was obtained from the electro- chemical impedance spectroscopy (EIS) method, was used to characterize the effect of pH value on the self-assembled monolayers (SAMs) of octadecanethiol(18SH) for the first time. The results not only strongly proved that inorganic ions could penetrate the SAMs of 18SH, but also ascertained that SAMs of 18SH were not an absolute of free of ion-penetration. Verifying the existence of pin-holes in the octadecanethiol SAMs was the main contribution of this paper, which coincided with the former conjecture very well.

  16. A smart DNA tetrahedron that isothermally assembles or dissociates in response to the solution pH value changes.

    Science.gov (United States)

    Liu, Zhiyu; Li, Yingmei; Tian, Cheng; Mao, Chengde

    2013-06-10

    This communication reports a DNA tetrahedron whose self-assembly is triggered by an acidic environment. The key element is the formation/dissociation of a short, cytosine (C)-containing, DNA triplex. As the solution pH value oscillates between 5.0 and 8.0, the DNA triplex will form and dissociate that, in turn, leads to assembly or disassembly of the DNA tetrahedron, which has been demonstrated by native polyacrylamide gel electrophoresis (PAGE). We believe that such environment-responsive behavior will be important for potential applications of DNA nanocages such as on-demand drug release.

  17. Femtosecond transient absorption spectroscopy study of the early events of norfloxacin in aqueous solutions with varying pH values.

    Science.gov (United States)

    Su, Tao; Li, Ming-De; Ma, Jiani; Wong, Naikei; Phillips, David Lee

    2014-11-26

    The photophysics and photochemistry of norfloxacin (NF) have been investigated in aqueous solutions of different pH using femtosecond transient absorption spectroscopy (fs-TA). Resonance Raman spectroscopic experiments on NF have also been conducted in aqueous solutions of different pH to characterize the vibrational and structural information on the initial forms of NF. The experimental results in combination with density functional theory calculations of the key intermediates help us to elucidate the early events for NF after photoexcitation in aqueous solutions with varying pH values. The fs-TA results indicate that NF mainly underwent photophysical processes on the early delay time scale (before 3 ns), and no photochemical reactions occurred on this time scale. Specifically, after the irradiation of NF, the molecule reaches a higher excited singlet Sn and then decays to the lowest-lying excited singlet state S1 followed by intersystem crossing to transform into the lowest-lying triplet state T1 with a high efficiency, with an exception that there is a lower efficiency observed in basic aqueous solution due to the generation of an intramolecular electron transfer as an additional pathway to waste energy.

  18. Toxicity and bioaccumulation of copper in Limnodrilus hoffmeisteri under different pH values: Impacts of perfluorooctane sulfonate.

    Science.gov (United States)

    Meng, Lingjun; Yang, Shaogui; Feng, Mingbao; Qu, Ruijuan; Li, Yong; Liu, Jiaoqin; Wang, Zunyao; Sun, Cheng

    2016-03-15

    Aquatic oligochaete Limnodrilus hoffmeisteri (L. hoffmeisteri) has been commonly used as a lethal and/or sub-lethal toxicological model organism in ecological risk assessments in contaminated water environments. In this study, experiments were conducted to investigate the potential toxic effects of copper (Cu(II)) with or without perfluorooctane sulfonate (PFOS) under different pH values (6.0, 7.0 and 8.0) on LC50, bioaccumulation, and oxidative stress biomarkers in L. hoffmeisteri after 3 and 7 days. The LC50 values of Cu(II) decreased with the increasing pH and the addition of PFOS. After each exposure, increasing bioaccumulation of Cu(II) in L. hoffmeisteri was observed in the combined exposure treatments, whereas the bioaccumulation of PFOS decreased. Moreover, the activity of superoxide dismutase, the level of glutathione, and the content of malondialdehyde were significantly altered after these exposures, possibly indicating that the bioaccumulation of Cu(II) and PFOS caused adverse effects on antioxidant defenses of L. hoffmeisteri. The integrated biomarker response index, indicates that the combined effect was proposed as synergism, which is coincided with the results of toxic unit. Moreover, this work showed that aquatic environment may become more livable when water conditions changed from acidic to near-neutral or alkaline.

  19. Fiber optic sensors for an in-situ monitoring of moisture and pH value in reinforced concrete

    Science.gov (United States)

    Grahn, Walter; Makedonski, Pavel; Wichern, Juergen; Kowalsky, Wolfgang; Wiese, Stefan

    2002-01-01

    Concrete structures such as social buildings and bridges are important economic goods. Thus, maintenance and preservation of these structures are of major interest. Buildings of reinforced concrete are exposed to a variety of damaging influences. In particular, moisture has an important influence on the lifetime of concrete structures. This is caused by the involvement of free water in corrosion of the steel, and the fact that water acts as transport medium for damaging ions such as chloride, sulfate, carbonate and ammonium. Thus, we designed and developed an integrated fiberoptical sensor system, which allows in-situ non- destructive long-term monitoring of concrete structures. As moisture indicator we use a pyridinium-N-phenolat betainital dye, which shows a strong solvatochromic behavior in the ultraviolet-visible spectral range (UV-VIS). The dye is embedded in a polymer matrix, whose moderate polarity is enhanced by free water diffusing into the sensor. This leads to a continuous hypsochromic shift of the absorption spectrum according to the water concetration. Another appropriate dye is 4-amino-N-methylphthalimid, which shows a similar behavior in its fluorescent spectra, and presently we are developing its derivatives and suitable polymer matrices. The determination of the pH-value of concrete is of major importance for the assessment of acidic attacks which may lead to serious damage in reinforced concrete, as the embedded steel structures exhibit long-term stability (i.e. resistance to corrosion) only at pH-values of 9 or higher. Therefore we have developed a fiberoptical sensor system for the measurement of pH-values in concrete consisting of pH- indicator dyes immobilized in a highly immobilized in a highly hydrophilic polymer matrix. Any change in pH-value of the wet concrete material is indicated by a color change of the dye/polymer system. The sensor system displays long term stability even in aggressive media of pH12 - 13.

  20. A Volume-Weighting Cloud-in-Cell Model for Particle Simulation of Axially Symmetric Plasmas

    Institute of Scientific and Technical Information of China (English)

    李永东; 何锋; 刘纯亮

    2005-01-01

    A volume-weighting cloud-in-cell (VW-CIC) model is developed to implement the particle-in-cell (PIC) simulation in axially symmetric systems. This model gives a first-order accuracy in the cylindrical system, and it is incorporated into a PIC code. A planar diode with a finite-radius circular emitter is simulated with the code. The simulation results show that the VW-CIC model has a better accuracy and a lower noise than the conventional area-weighting cloud-in-cell (AW-CIC) model, especially on those points near the axis. The two-dimensional (2-D) space-charge-limited current density obtained from VW-CIC model is in better agreement with Lau's analytical result. This model is more suitable for 2.5-D PIC simulation of axially symmetric plasmas.

  1. Influences of Temperature and pH Value on the Corrosion Behaviors of X80 Pipeline Steel in Carbonate/Bicarbonate Buffer Solution

    Institute of Scientific and Technical Information of China (English)

    LI,Jin-Bo; ZUO,Jian-E

    2008-01-01

    The joint effect of temperature and pH value on the corrosion behavior of X80 steel in carbonate/bicarbonate buffer solution was detected by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Mott-Schottky analysis. The results show that an unstable corrosion film will be formed on the X80 steel surface in low pH value solutions, and a better protective corrosion film can be formed on the X80 steel surface in high pH value solutions. On the whole, the corrosion film resistance and transfer resistance increase with the increment of pH value, and decrease with increase of solution temperature, which indicates that the protective effect of the corrosion film on X80 steel is enhanced with increasing pH value and decreasing the solution temperature. The corrosion film formed on X80 steel surface in carbonate/bicarbonate buffer solution has an n-type semi-conductive character, and the donor density decreases with increasing the pH value, and increases with increasing the solution temperature. The flat-band potential and pH value have a linear relationship with a positive slope.

  2. Continuous measurement of reticuloruminal pH values in dairy cows during the transition period from barn to pasture feeding using an indwelling wireless data transmitting unit.

    Science.gov (United States)

    Gasteiner, J; Horn, M; Steinwidder, A

    2015-04-01

    This study was performed to investigate the effect of the transition from barn feeding to pasture on the pattern of reticuloruminal pH values in 8 multiparous dairy cows. A indwelling wireless data transmitting system for pH measurement was given to 8 multiparous cows orally. Reticuloruminal pH values were measured every 600 s over a period of 42 days. After 7 days of barn feeding (period 1), all of the animals were pastured with increasing grazing times from 2 to 7 h/day over 7 days (period 2). From day 15 to day 21 (period 3), the cows spent 7 h/day on pasture. Beginning on day 22, the animals had 20 h/day access to pasture (day and night grazing). To study reticuloruminal adaptation to pasture feeding, the phase of day and night grazing was subdivided into another 3 weekly periods (periods 4-6). Despite a mild transition period from barn feeding to pasture, significant effects on reticuloruminal pH values were observed. During barn feeding, the mean reticuloruminal pH value for all of the cows was 6.44 ± 0.14, and the pH values decreased significantly (p pH values increased again (pH 6.25 ± 0.22; pH 6.31 ± 0.17; pH 6.37 ± 0.16). Our results showed that the animals had significantly lowered reticuloruminal pH during the periods of feed transition from barn to pasture feeding. Despite these significant changes, the decrease was not harmful, as indicated by data of feed intake and milk production.

  3. [Osmotic modification of thermal damage in Escherichia coli bacteria at various pH values of the media].

    Science.gov (United States)

    Morozov, I I; Petin, V G

    2000-01-01

    A study was made of the influence of media with different osmotic pressure on cell survival and on optic density of supernatants from Escherichia coli B/r and E. coli Bs-1 cell suspensions heated under different pH values of media. Hyperthermia induced cell death accompanied with the loss of optically active (lambda = 260 nm) material. Both cell damage effects were increased in acid and alkaline conditions, compared to neutral condition of heating. Hypertonic media results in a decrease in thermic cell death and loss of cell substances. Under this condition, the protection influence of high osmotic pressure was seen to increase significantly in acid and alkaline conditions of heating, compared to neutral condition. It has been proposed that a higher thermal damage of microorganisms in acid and alkaline beating conditions and protection influence of hypertonic media, especially expressed in acid and alkaline medium, is caused to a great extent by the status of osmotic cell homeostasis.

  4. Utilization of slaked lime for the regulation of pH value in the process of copper

    Directory of Open Access Journals (Sweden)

    Petković Aleksandar V.

    2009-01-01

    Full Text Available The investigations of used lime at plant from company Messer-Tehnogas, Belgrade, were in the aim to improvement technologically results from flotation concentration of copper minerals in flotation plant Veliki Krivelj. This paper shows usage of slaked lime, which is waste in the process of technical gas production, for regulation of pH value in the process of copper minerals flotation concentration. It is important to point out that slaked lime is a waste material that is not dangerous. Preparation and dosage includes preparation procedures, which enable introduction into flotation process with the aim of achieving better results. Lime from Limekiln Zagrađe is brought into four storage places in flotation. Volume of each storage place is 80 m3. Lime in pieces from storage place is added by airbladders on transportation line and by system of transportation lines lime gets to the ball mill. At the mill entrance water is added and then follows lime grinding. Milk glass of lime thus prepared goes to the pump basket from where is transported by pipeline to conditioner, and then by manual and (or automatic valves it is dosed to the flotation concentration of copper minerals process. Prospect of advancement and rationalization of the used lime in flotation plant Bor, Veliki Krivelj and Majdanpek as well as a way to link different branches of industry was demonstrated. Total cost of lime supplying, transporting, preparation and distribution related slaked lime is lower for 2.955 din/kg. Particularly, using lime from Messer in content of 2.1 g/l value of pH 11.82 is possible to obtain.

  5. Glycolytic potential and ultimate muscle pH values in red deer (Cervus elaphus and fallow deer (Dama dama

    Directory of Open Access Journals (Sweden)

    Eva Wiklund

    2004-04-01

    Full Text Available The ultimate pH value of meat (measured at approx. 24 hours post slaughter gives information about the technological quality, i.e. shelf life, colour, water-holding properties and tenderness and is a direct consequence of muscle glycogen (energy levels at slaughter. It may therefore also indicate whether or not the animal has been exposed to stressful energy depleting events prior to slaughter. In the present study, 141 animals (130 red deer (Cervus elaphus and 11 fallow deer (Dama dama were included to investigate the relationship between ultimate pH and residual glycogen concentration in red deer and fallow deer M. longissimus. In addition, the muscle glycogen content and ultimate pH values in three red deer muscles (Mm. triceps brachii, longissimus and biceps femoris were studied. M. triceps brachii had higher ultimate pH and lower glycogen content compared with the other two studied muscles. The frequency of intermediate DFD (5.8≤ pH<6.2 was 5.4% in red deer M. longissimus, compared with 9.1% in fallow deer, while the frequency of DFD (pH≥ 6.2 was much lower in red deer (3.8% than in fallow deer (54.5%. A curvilinear relationship between ultimate pH and total glucose concentration (glycogen and glucose 30 min post slaughter in red deer and fallow deer M. longissimus was found. The relationship between muscle pH and lactic acid concentration however, was indicated to be linear. A significant variation in total glucose concentration at ultimate pH below 5.80 was observed, including values in the range from 18 to 123 mmol/kg wet tissue. It was concluded that further studies are needed to further explore the relationship between muscle glycogen content and technological and sensory quality attributes of meat from different deer species.Abstract in Swedish / Sammanfattning:Köttets pH-värde (mätt ca 24 timmar efter slakt har stor betydelse för den teknologiska kvaliteten som t. ex. hållbarhet, färg, vattenhållande förmåga och m

  6. Effect of glycerol content and pH value of film-forming solution on the functional properties of protein-based edible films

    Directory of Open Access Journals (Sweden)

    Nemet Nevena T.

    2010-01-01

    Full Text Available The work is concerned with the effects of glycerol content and pH value of film forming solution on the functional properties of protein-based films. The films were produced of chicken breast proteins, dissolved under either acidic (pH 3 or alkaline (pH 11 conditions, with different concentrations of glycerol (35%, 50% and 65% w/w of protein content. Glycerol content affected significantly mechanical properties, water vapor permeability, color at pH 3 and film solubility (p<0.05. The pH value had significant influence on light transmission, color, transparency and film solubility (p<0.05. Considering the results of mechanical properties and film solubility, the obtained films are in the acceptable range for the use as a packaging material. It was estimated that water vapor permeability, color, light transmission and transparency need to be improved for the application.

  7. The effect of prolonged immersion of giomer bulk-fill composite resin on the pH value of artificial saliva and resin surface roughness

    Science.gov (United States)

    Ratna, A. A.; Triaminingsih, S.; Eriwati, Y. K.

    2017-08-01

    This study aimed to determine the effect of immersion time on the surface roughness of Giomer Bulk-Fill composite resin and on the pH value of artificial saliva. Sixty-three specimens were divided into nine groups and immersed in artificial saliva with pH values of 7, 5.5, and 4.5 for 1 hour, 24 hours, and 72 hours at 37 °C. The changes in artificial saliva pH were measured using a pH meter and the surface roughness was measured using a surface roughness tester. Longer immersion time increases the pH of artificial saliva and the surface roughness of Giomer Bulk-Fill composite resin.

  8. Effect of pH value on particle morphology and electrochemical properties of LiFePO{sub 4} by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Song, Qingzhu, E-mail: qingzhu0812@163.com [Key Laboratory for New Type of Functional Materials in Hebei Province (China); Institute of Power Sources and Eco-Materials Science, Box 1055, Hebei University of Technology, Tianjin 300130 (China); Ou, Xiuqin, E-mail: ouxiuqin@hebut.edu.cn [Key Laboratory for New Type of Functional Materials in Hebei Province (China); Institute of Power Sources and Eco-Materials Science, Box 1055, Hebei University of Technology, Tianjin 300130 (China); Wang, Li, E-mail: tigerwl29@yahoo.com.cn [Key Laboratory for New Type of Functional Materials in Hebei Province (China); Institute of Power Sources and Eco-Materials Science, Box 1055, Hebei University of Technology, Tianjin 300130 (China); Liang, Guangchuan, E-mail: liangguangchuan@hebut.edu.cn [Key Laboratory for New Type of Functional Materials in Hebei Province (China); Institute of Power Sources and Eco-Materials Science, Box 1055, Hebei University of Technology, Tianjin 300130 (China); Wang, Zuorui, E-mail: Bluetianlan001@163.com [Key Laboratory for New Type of Functional Materials in Hebei Province (China); Institute of Power Sources and Eco-Materials Science, Box 1055, Hebei University of Technology, Tianjin 300130 (China)

    2011-09-15

    Graphical abstract: The pH value of system is adjusted in the range of 2.5-8.8 by using dilute sulfuric acid and ammonia water. The results indicated that the particle exhibits acute angle diamond flake-like morphology at pH = 2.5. With increase of pH value, the particle gradually becomes to round flake-like and irregular flake-like morphology. The optimal sample synthesized at pH = 6.4 exhibits discharge capacities of 151.8 mAh g{sup -1} at 0.2 C rate and 129.3 mAh g{sup -1} at 3 C rate. Highlights: {yields} The pH value of solution affects greatly on particle morphology. {yields} The solubility product determined the transition of interphases. {yields} The disorder of atoms in crystal is affected by pH value. {yields} LiFePO{sub 4} with high capacity could be synthesized at slight acid or neutral conditions. -- Abstract: Lithium iron phosphate was prepared by hydrothermal synthesis using LiOH.H{sub 2}O, FeSO{sub 4}.7H{sub 2}O and H{sub 3}PO{sub 4} as raw materials. The effects of pH value of reaction solution on particle morphology and electrochemical property were investigated. The pH value of the reaction solution was adjusted in the range of 2.5-8.8 by dilute sulfuric acid and ammonia water. The samples were characterized by field-emission scanning electronic microscope (FE-SEM), X-ray powder diffraction (XRD), constant-current charge/discharge cycling tests and chemical analysis. The results indicated that the particles exhibited acute angle diamond flake-like morphology at pH = 2.5, and as the pH value increased, the particle became hexagon flake-like, round flake-like and irregular flake-like morphology gradually. The optimal sample synthesized at pH = 6.4 exhibited discharge capacities of 151.8 mAh g{sup -1} at 0.2 C rate and 129.3 mAh g{sup -1} at 3 C rate. It was found that pH value affected the morphologies and properties of the product by means of different crystal growth rates.

  9. Volume weighting the measure of the universe from classical slow-roll expansion

    Science.gov (United States)

    Sloan, David; Silk, Joseph

    2016-05-01

    One of the most frustrating issues in early universe cosmology centers on how to reconcile the vast choice of universes in string theory and in its most plausible high energy sibling, eternal inflation, which jointly generate the string landscape with the fine-tuned and hence relatively small number of universes that have undergone a large expansion and can accommodate observers and, in particular, galaxies. We show that such observations are highly favored for any system whereby physical parameters are distributed at a high energy scale, due to the conservation of the Liouville measure and the gauge nature of volume, asymptotically approaching a period of large isotropic expansion characterized by w =-1 . Our interpretation predicts that all observational probes for deviations from w =-1 in the foreseeable future are doomed to failure. The purpose of this paper is not to introduce a new measure for the multiverse, but rather to show how what is perhaps the most natural and well-known measure, volume weighting, arises as a consequence of the conservation of the Liouville measure on phase space during the classical slow-roll expansion.

  10. Investigation on the Key Factors and the Solution for pH Value Decrease in Carbon Filter in O3-BAC Process

    Institute of Scientific and Technical Information of China (English)

    陆少鸣; 陈江玲; 李芳

    2013-01-01

    An investigation was carried out to eliminate the decrease of effluent pH value in carbon filter in O3-biological activated carbon process. The influence factors were examined in a pilot test, and pH was adjusted in the pilot and waterworks. Results show that the carbon filter is an acid-base buffer system and the activated carbon is the key factor. Chemical functional groups on activated carbon surface present acid-base properties to buffer the water but decrease with time, so that effluent pH value decreases. The effects of ozone dosage, CO2 in the carbon filter, and the filter influent quality are negligible. A new method to adjust pH is developed:the activated carbon is first modified by soaking in sodium hydroxide solution to make its pH reach the desired value, and then the pH value of inflow is controlled to certain value by dosing lime in sand filter influent. The method is economical and effective.

  11. Influence of bath PH value on microstructure and corrosion resistance of phosphate chemical conversion coating on sintered Nd-Fe-B permanent magnets

    Science.gov (United States)

    Ding, Xia; Xue, Long-fei; Wang, Xiu-chun; Ding, Kai-hong; Cui, Sheng-li; Sun, Yong-cong; Li, Mu-sen

    2016-10-01

    The effect of bath PH value on formation, microstructure and corrosion resistance of the phosphate chemical conversion (PCC) coatings as well as the effect on the magnetic property of the magnets is investigated in this paper. The results show that the coating mass and thickness increase with the decrease of the bath PH value. Scanning electron microscopy observation demonstrates that the PCC coatings are in a blocky structure with different grain size. Transmission electron microscope and X-ray diffractometer tests reveal the coatings are polycomponent and are mainly composed of neodymium phosphate hydrate and praseodymium phosphate hydrate. The electrochemical analysis and static immersion corrosion test show the corrosion resistance of the PCC coatings prepared at bath PH value of 0.52 is worst. Afterwards the corrosion resistance increases first and then decreases with the increasing of the bath PH values. The magnetic properties of all the samples with PCC treatment are decreased. The biggest loss is occurred when the bath PH value is 0.52. Taken together, the optimum PH range of 1.00-1.50 for the phosphate solution has been determined.

  12. Optimizing isothiocyanate formation during enzymatic glucosinolate breakdown by adjusting pH value, temperature and dilution in Brassica vegetables and Arabidopsis thaliana

    Science.gov (United States)

    Hanschen, Franziska S.; Klopsch, Rebecca; Oliviero, Teresa; Schreiner, Monika; Verkerk, Ruud; Dekker, Matthijs

    2017-01-01

    Consumption of glucosinolate-rich Brassicales vegetables is associated with a decreased risk of cancer with enzymatic hydrolysis of glucosinolates playing a key role. However, formation of health-promoting isothiocyanates is inhibited by the epithiospecifier protein in favour of nitriles and epithionitriles. Domestic processing conditions, such as changes in pH value, temperature or dilution, might also affect isothiocyanate formation. Therefore, the influences of these three factors were evaluated in accessions of Brassica rapa, Brassica oleracea, and Arabidopsis thaliana. Mathematical modelling was performed to determine optimal isothiocyanate formation conditions and to obtain knowledge on the kinetics of the reactions. At 22 °C and endogenous plant pH, nearly all investigated plants formed nitriles and epithionitriles instead of health-promoting isothiocyanates. Response surface models, however, clearly demonstrated that upon change in pH to domestic acidic (pH 4) or basic pH values (pH 8), isothiocyanate formation considerably increases. While temperature also affects this process, the pH value has the greatest impact. Further, a kinetic model showed that isothiocyanate formation strongly increases due to dilution. Finally, the results show that isothiocyanate intake can be strongly increased by optimizing the conditions of preparation of Brassicales vegetables.

  13. Stability of the calcium hydroxyzincate protective layer developed on galvanized reinforcements after a further increase of the pH value

    OpenAIRE

    Andrade, C.; Macías, A

    1986-01-01

    In previous works on galvanized reinforcements in contact with Ca- containing highly alkaline media, the authors have reported the existence of a threshold pH of 13,3 ± 0,1, below which the Zn in contact with such a medium is passivated by formation of a continuous layer of calcium hydroxyzincate, but at pH values above this it corrodes continuously until it totally disappears. The investigation on the stability of the calcium hydroxyzincate layer after an increase of the pH to very high...

  14. Investigation of the adsorption of anionic surfactants at different pH values by means of active carbon and the kinetics of adsorption

    OpenAIRE

    2004-01-01

    In this study, the effect of pH on the removal of anionic surfactants, such as linear alkyl benzene sulfonate (LABS) and dodecyl benzene sulfonate (DBS) by means of adsorption by activated carbon was investigated. For this purpose activated carbon was used as adsorbent. Anionic surfactant solutions with initial pH values of 3, 6, 8 and 12 were used. The adsorption isotherms for the adsorption of anionic surfactants by active carbon at different pH were determined. These adsorption isotherms w...

  15. Effect of dipping solution pH values on electrostatic layer-by-layer self-assembly of side-chain azo polyelectrolyte

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effect of pH value on the electrostatic layer-by-layer self-assembly and the photo-responsive behavior of Poly{2-[4-(4-ethoxyphenylazo)phenoxy]ethyl acrylate-co-acrylic acid} (PEAPE) was studied.Results show that in the studied pH value range,the lower the pH value is,the higher is the UV-vis absorbance and the larger is the thickness of the multilayer films.FTIR studies indicate that the azo polyelectrolyte exhibits a different ionization degree in solutions with different pH values.The higher absorbance and the larger thickness of the layer-by-layer films can be attributed to the low ionization degree and the shrinkage conformation of PEAPE in the solution with low pH values.FTIR analysis also confirms that the driving force for layer-by-layer self-assembly of PEAPE and PDAC is the electrostatic interaction.

  16. Ex situ and in situ AFM investigations on the growth of the (100) face of KDP with different pH values

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Through investigations on the growth of the (100) face of potassium dihydrogen phosphate (KDP) crystal by ex situ atomic force microscopy (AFM) with different pH values at different supersaturations at 40°C,it was found that the growth of crystal was controlled by step flow at lower supersaturations,and the morphologies of steps were different under different growth conditions.In addition,at the higher supersaturations,2D nucleation mechanism controlled the growth.When the supersaturations were lower,the dislocation mechanism controlled the growth of crystal,and when σ≥0.05,2D nucleation mechanism played a dominant role in the growth of the (100) face for pH=4.2 and pH=2.5.However,for pH=5.0,the dislocation mechanism also dominated the growth of crystal when the supersaturations were lower,but when σ≥0.03,the crystal growth was controlled by 2D nucleation mechanism.Through investigations on the step flow of the (100) face of KDP crystal by in situ AFM with different pH values at lower supersaturations at 25°C,the velocities of normal growth of the (100) face were estimated at different growth conditions by in situ AFM.It was found that when the pH value was 5.0,the normal growth rate was the fastest at the same supersaturation compared to the other pH values and screw dislocation mechanism controlled the crystal growth.In addition,we found that with the reduction of the supersaturation of the solution,the density of steps also decreased,the width of steps became larger.Finally,a phenomenon which was the obvious anisotropic growth of steps in the step flow was observed by in situ AFM at σ=0.025 at pH=5.0.

  17. Kinetics of an acid-base catalyzed reaction (aspartame degradation) as affected by polyol-induced changes in buffer pH and pK values.

    Science.gov (United States)

    Chuy, S; Bell, L N

    2009-01-01

    The kinetics of an acid-base catalyzed reaction, aspartame degradation, were examined as affected by the changes in pH and pK(a) values caused by adding polyols (sucrose, glycerol) to phosphate buffer. Sucrose-containing phosphate buffer solutions had a lower pH than that of phosphate buffer alone, which contributed, in part, to reduced aspartame reactivity. A kinetic model was introduced for aspartame degradation that encompassed pH and buffer salt concentrations, both of which change with a shift in the apparent pK(a) value. Aspartame degradation rate constants in sucrose-containing solutions were successfully predicted using this model when corrections (that is, lower pH, lower apparent pK(a) value, buffer dilution from the polyol) were applied. The change in buffer properties (pH, pK(a)) from adding sucrose to phosphate buffer does impact food chemical stability. These effects can be successfully incorporated into predictive kinetic models. Therefore, pH and pK(a) changes from adding polyols to buffer should be considered during food product development.

  18. Influences of pH value in deposition-precipitation synthesis process on Pt-doped TiO2 catalysts for photocatalytic oxidation of NO

    Institute of Scientific and Technical Information of China (English)

    Shuzhen Song; Zhongyi Sheng; Yue Liu; Haiqiang Wang; Zhongbiao Wu

    2012-01-01

    This work has been undertaken to study the influences of pH value on the characteristics and activity of photocatalyst by deposition-precipitation method during its preparation process.A series of Pt-modified TiO2 were prepared by deposition-precipitation method at different pH values as well as wet impregnation method,and characterized by XRD,XPS,TEM,UV-Vis and photoluminescence(PL).It was found that the catalysts had the highest photocatalytic activity for NO conversion when pH value was kept at around 7.And the sample prepared by deposition-precipitation method showed higher activity than that by impregnation method.This was mainly due to their high value in highly-dispersed platinum oxides(PtOx)content on the surface of the catalysts.The results from UV-Vis absorption showed that highest absorbance was obtained for Pt/TiO2 prepared at pH values of around 7.And PL spectra results indicated that the recombination rate of photogenerated electrons and holes of the samples prepared by deposition-precipitation method was lower than that prepared by impregnation method.And in the zeta potential study,the pH values for the isoelectric point of the preparing slurry of 0.05 wt.%Pt/TiO2 and 0.5 wt.%Pt/TiO2 were determined to be 6.5-8.5,which further confirmed the enrichment of PtOx dopants for the catalysts repapered when pH value was around 7.

  19. [Short-term changes of pH value and Al activity in acid soils after urea fertilization].

    Science.gov (United States)

    Zeng, Qingru; Liao, Bohan; Jiang, Zhaohui; Zhou, Xihong; Tang, Can; Zhong, Ning

    2005-02-01

    Acidic soils are widely distributed in South China, and their acidity is the major environmental stress factor limiting the growth of most crops. It is well known that soil Al solubilized at low pH is a main toxic factor for plant growth. Our study with three acidic soils showed that soil pH increased quickly, while soil exchangeable Al decreased sharply with the increasing concentrations of applied urea. The time-course experiment revealed that the increase of soil pH was short-lived, with a subsequently slow drop after reached its maximum. Urea fertilization caused a drastic change of soil pH during 2-4 weeks of the experimental period. There was a negative relationship between soil pH and soil exchangeable Al. Biological toxicity test demonstrated that applying urea to acidic soils could obviously decrease the aluminum toxicity of maize in a short-term period.

  20. 废水处理中pH值的PLC自动控制系统%PLC automatic control system of pH value in wastewater treatment.

    Institute of Scientific and Technical Information of China (English)

    李安峰; 张志群; 丁庭华; 王绍堂

    2001-01-01

    The pH value automatic control is a key link in the treatment of industrial wastewater. Based on much literature review, a new PLC automatic control system, suitable for pH value control in the wastewater treatment, is developed with simple structure and good control effect, which offers a practical approach for pH value automatic control in the treatment of industrial wastewater.%pH值自动控制是工业废水处理过程中的关键环节.在查阅大量文献的基础上,研究出一套新的适于污水处理pH值控制的结构简单且控制效果良好的PLC自动控制系统,为工业废水处理的pH值自动控制提供了一条切实可行的途径.

  1. Effect of pH value of poly(ethylenimine)-H 2SO 4 electrolyte on electrochromic response of polyaniline thin films

    Science.gov (United States)

    Hu, Hailin; Ortíz-Aguilar, Blanca E.; Hechavarría, Liliana

    2007-02-01

    Electrochromic devices (ECDs) are electrochemical cells with one or two electrochemically active coatings that change color during the reduction-oxidation process. In this work an electrochromic polyaniline (PANI) thin film and a viscous electrolyte, formed by mixing a basic aqueous solution of polyethylenimine (PEI) and concentrated sulfuric acid (H 2SO 4), have been used as the main components of an ECD. The pH value of the electrolyte is a function of the relative proportion between PEI and H 2SO 4. Fourier transform infrared spectroscopy (FT-IR) results show that for those PEI-H 2SO 4 complexes of pH value varied from 2 to 9 sulfate ions of the inorganic acid are associated to the imine groups of PEI. If the pH value of the same system is lower than or equal to 1, HSO4- anions appear in the electrolyte together with a notable reduction of the free water content. Electrochemical impedance spectroscopy study of these electrolytes show that the protonic conductivity of the PEI-H 2SO 4 complex with pH 1 is almost three orders of magnitude lower than that of the same electrolytes but with a pH value between 2 and 6. Optical switch speed of a PANI/PEI-H 2SO 4 based ECD at 550 nm under a square potential application of +1.2 V and -1.2 V is proportional to the ionic conductivity of the electrolyte of the device.

  2. Crescimento de Bradyrhizobium elkanii estirpe Br 29 em meios de cultivo com diferentes valores de pH inicial Growth of Bradyrhizobium elkanii strain Br 29 in culture media with different pH values

    Directory of Open Access Journals (Sweden)

    Alexandre Barberi

    2004-04-01

    obtained or if tolerance to acidity could be induced. Some papers demonstrated induced tolerance to acidity when the bacterium is previously exposed to a slightly acid pH. The aim of this study was to verify the growth of Bradyrhizobium elkanii strain Br 29 in culture media with different pH values (6.8; 6.0; 5.5. Two experiments were carried out with two different culture media varying mainly regarding initial pH. Strain growth, by optical density and colony forming units (CFU number, and pH medium modification were evaluated. Growth curves varied either in accordance with pH or culture media composition. Growth based on maximum number of CFU.mL-1 was better at pH 5.5 in Lopreto medium and at pH 6.0 at Lorda and Balatti medium. Better growth on lowest pH (5.5 was related to greater exopolyssacaride production.

  3. Stabilization of Organic Matter by Biochar Application in Compost-amended Soils with Contrasting pH Values and Textures

    Directory of Open Access Journals (Sweden)

    Shih-Hao Jien

    2015-09-01

    Full Text Available Food demand and soil sustainability have become urgent concerns because of the impacts of global climate change. In subtropical and tropical regions, practical management that stabilizes and prevents organic fertilizers from rapid decomposition in soils is necessary. This study conducted a short-term (70 days incubation experiment to assess the effects of biochar application on the decomposition of added bagasse compost in three rural soils with different pH values and textures. Two rice hull biochars, produced through slow pyrolization at 400 °C (RHB-400 and 700 °C (RHB-700, with application rates of 1%, 2%, and 4% (w/w, were separately incorporated into soils with and without compost (1% (w/w application rate. Experimental results indicated that C mineralization rapidly increased at the beginning in all treatments, particularly in those involving 2% and 4% biochar. The biochar addition increased C mineralization by 7.9%–48% in the compost-amended soils after 70 days incubation while the fractions of mineralized C to applied C significantly decreased. Moreover, the estimated maximum of C mineralization amount in soils treated with both compost and biochar were obviously lower than expectation calculated by a double exponential model (two pool model. Based on the micromorphological observation, added compost was wrapped in the soil aggregates formed after biochar application and then may be protected from decomposing by microbes. Co-application of compost with biochar may be more efficient to stabilize and sequester C than individual application into the studied soils, especially for the biochar produced at high pyrolization temperature.

  4. [Effects of pH value on the adsorption and degradation of 2, 4-DCP by nanoscale zero-valent iron].

    Science.gov (United States)

    Feng, Li; Ge, Xiao-Peng; Wang, Dong-Sheng; Tang, Hong-Xiao

    2012-01-01

    To evaluate the effect of pH on the degradation of 2,4-DCP by zero-valent iron nanoparticles (with the particle size of 30-40 nm in diameter) samples were taken for TEM, SEM-EDX, and ICP-OES analysis and investigated on the particle morphology changes and 2,4-DCP removal under different pH conditions. It is shown that iron nanoparticles agglomerate from individual particles and tiny clusters into massive aggregate assemblies with their surfaces oxidized and coated by the needle-like rotten iron oxide products (FeOOH) in the degradation process, which will block up a further reaction of 2,4-DCP dechlorination, while the low pH value condition in acidic system can effectively suppress particles aggregation and the surface oxidation, although iron loss in the solid phase is somehow inevitable. Large quantity of Fe2+ ions soaked out from iron nanoparticles significantly promote 2,4-DCP removal by reduction, and the solution pH tends to go up in the reaction process. Acidic conditions facilitate 2,4-DCP dechlorination, and the removal efficiency became higher with the pH reduced, in which 90% of 2,4-DCP removal is reached in 24 h under the pH value of 3.

  5. Proposal of a New SI Base Unit for Value. An Hedonic Estimation of the Physical Purchasing Power (PhPP) of Money.

    Science.gov (United States)

    Defilla, Steivan

    2006-03-01

    Hitherto, the purchasing power of money, i.e. its transaction value, has been measured in terms of inflation index numbers and consumer baskets. Consumer baskets are variable phenomena and their use as measurement units for value confuses the measuring with the measurand. We propose an invariant numeraire, or value unit, based on the market value of a Planck energy (1956 MJ). Planck units form a natural system of units independent of any civilization. The hedonic estimation of the PhPP of a currency differentiates energy by product as well as by thermodynamic quality (exergy). Following SI rules, we propose to name the value unit walras (Wal) in honour of the economist Leon Walras (1834 - 1910). One Wal can also be interpreted as the minimum cost of physiological life of a reference person during one year. The study uses official disaggregated Swiss Producer and Consumer Price Index data and estimates the PhPP of the Swiss franc in 2003.

  6. Variation in structural and dielectric properties of co-precipitated nanoparticles strontium ferrites due to value of pH

    Energy Technology Data Exchange (ETDEWEB)

    Anis-ur-Rehman, M., E-mail: marehman@comsats.edu.pk [Applied Thermal Physics Laboratory, Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan); Asghar, G. [Applied Thermal Physics Laboratory, Department of Physics, COMSATS Institute of Information Technology, Islamabad 44000 (Pakistan)

    2011-01-12

    Nanoparticles of strontium ferrites with nominal composition SrFe{sub 12}O{sub 19} were prepared by co-precipitation method, by decreasing pH from 13 to 8 with a regular step of 1. The secondary phase of {alpha}-Fe{sub 2}O{sub 3} was increased with the decrease in pH. The crystallite size estimated from X-rays diffraction data was in the range 52-70 nm, which is much smaller than that already reported. Most of the particles formed had hexagonal structure, as observed by the scanning electron microscopy. Particle size and dielectric loss were increased where as dc electrical resistivity and dielectric constant were decreased with decrease in pH. The results show that the material synthesized with higher pH is phase pure and is potentially more suitable for high frequency applications.

  7. Heat-denaturation and aggregation of quinoa (Chenopodium quinoa) globulins as affected by the pH value.

    Science.gov (United States)

    Mäkinen, Outi E; Zannini, Emanuele; Koehler, Peter; Arendt, Elke K

    2016-04-01

    The influence of heating (100 °C; 0-15 min) on the relative molecular mass, protein unfolding and secondary structure of quinoa globulins was studied at pH 6.5 (low solubility), 8.5 and 10.5 (high solubility). The patterns of denaturation and aggregation varied with pH. Heating triggered the disruption of the disulfide bonds connecting the acidic and basic chains of the chenopodin subunits at pH 8.5 and 10.5, but not at pH 6.5. Large aggregates unable to enter a 4% SDS-PAGE gel were formed at pH 6.5 and 8.5, which became soluble under reducing conditions. Heating at pH 10.5 lead to a rapid dissociation of the native chenopodin and to the disruption of the subunits, but no SDS-insoluble aggregates were formed. No major changes in secondary structure occurred during a 15 min heating, but an increase in hydrophobicity indicated unfolding of the tertiary structure in all samples.

  8. Determination of Trace Elements,Tannin,Flavonoids and pH Value in Marigold%万寿菊中微量元素、单宁、黄酮含量及 pH 值的测定

    Institute of Scientific and Technical Information of China (English)

    刘云华; 韩辉; 王吉秀; 张仙; 黄渝翔; 殷彩霞

    2014-01-01

    The contents of trace elements,tannin,flavonoids and pH value of petals,seeds,aerial part remo-ving the petals and seeds,and the underground part of marigold were determined and the correlation were ana-lyzed.The results showed:the content of Zn in different parts was the highest;the content of each trace element in seeds was the highest;the contents of tannin and flavonoids in petals were the highest,but its pH value were the lowest;the content correlations of As with Pb,flavonoids with As or Pb were significant.%分别对万寿菊花瓣、种子、地上(除去花瓣和种子)及地下部分的微量元素、单宁、黄酮含量及 pH 值进行了测定,并分析了其相关性。结果显示:种子中各微量元素的含量均较高;不同部位中微量元素 Zn 的含量最高;花瓣中的单宁含量和黄酮含量最高,但 pH 值最小;As 与 Pb 显著相关,As、Pb 与黄酮含量显著相关。

  9. X-ray absorption near-edge structure study on the configuration of Cu 2+ /histidine complexes at different pH values

    Science.gov (United States)

    Mei-Juan, Yu; Yu, Wang; Wei, Xu

    2016-04-01

    The local configurations around metal ions in metalloproteins are of great significance for understanding their biological functions. Cu2+/histidine (His) is a typical complex existing in many metalloproteins and plays an important role in lots of physiological functions. The three-dimensional (3D) structural configurations of Cu2+/His complexes at different pH values (2.5, 6.5, and 8.5) are quantitatively determined by x-ray absorption near-edge structure (XANES). Generally Cu2+/His complex keeps an octahedral configuration consisting of oxygen atoms from water molecules and oxygen or nitrogen atoms from histidine molecules coordinated around Cu2+. It is proved in this work that the oxygen atoms from water molecules, when increasing the pH value from acid to basic value, are gradually substituted by the Ocarboxyl, Nam, and Nim from hisitidine molecules. Furthermore, the symmetries of Cu2+/His complexes at pH 6.5 and pH 8.5 are found to be lower than at pH 2.5. Project supported by the National Natural Science Foundation of China (Grant No. 11205186).

  10. Stability of the calcium hydroxyzincate protective layer developed on galvanized reinforcements after a further increase of the pH value

    Directory of Open Access Journals (Sweden)

    Andrade, C.

    1986-12-01

    Full Text Available In previous works on galvanized reinforcements in contact with Ca- containing highly alkaline media, the authors have reported the existence of a threshold pH of 13,3 ± 0,1, below which the Zn in contact with such a medium is passivated by formation of a continuous layer of calcium hydroxyzincate, but at pH values above this it corrodes continuously until it totally disappears. The investigation on the stability of the calcium hydroxyzincate layer after an increase of the pH to very high alkaline values, is the aim of the present paper. It has been establised that if the calcium hydroxyzincate is perfectly developed, a later increase of the pH does not affect the stability.

    En trabajos anteriores que estudian el comportamiento de armaduras galvanizadas en contacto con medios muy alcalinos que contienen calcio, los autores han señalado la existencia de un umbral de pH = 13,3 ±0,1 por debajo del cual el Zn en contacto con tales medios se pasiva por formación de una capa continua de hidroxizincato calcico, mientras que para valores de pH superiores se corroe continuamente hasta su total desaparición. Establecer la estabilidad del recubrimiento protector de hidroxizincato calcico a un aumento de pH a valores muy alcalinos posterior a su formación, es el objetivo del presente artículo. Como resultado de las investigaciones realizadas ha podido concluirse que si el recubrimiento de hidroxizincato cálcico se ha desarrollado perfectamente, un posterior incremento del pH del medio no afecta su estabilidad.

  11. Determination and Visualization of pH Values in Anaerobic Digestion of Water Hyacinth and Rice Straw Mixtures Using Hyperspectral Imaging with Wavelet Transform Denoising and Variable Selection

    Directory of Open Access Journals (Sweden)

    Chu Zhang

    2016-02-01

    Full Text Available Biomass energy represents a huge supplement for meeting current energy demands. A hyperspectral imaging system covering the spectral range of 874–1734 nm was used to determine the pH value of anaerobic digestion liquid produced by water hyacinth and rice straw mixtures used for methane production. Wavelet transform (WT was used to reduce noises of the spectral data. Successive projections algorithm (SPA, random frog (RF and variable importance in projection (VIP were used to select 8, 15 and 20 optimal wavelengths for the pH value prediction, respectively. Partial least squares (PLS and a back propagation neural network (BPNN were used to build the calibration models on the full spectra and the optimal wavelengths. As a result, BPNN models performed better than the corresponding PLS models, and SPA-BPNN model gave the best performance with a correlation coefficient of prediction (rp of 0.911 and root mean square error of prediction (RMSEP of 0.0516. The results indicated the feasibility of using hyperspectral imaging to determine pH values during anaerobic digestion. Furthermore, a distribution map of the pH values was achieved by applying the SPA-BPNN model. The results in this study would help to develop an on-line monitoring system for biomass energy producing process by hyperspectral imaging.

  12. Study on Effects of Bait pH Values on Termite Feeding%诱饵pH值对白蚁取食影响的研究

    Institute of Scientific and Technical Information of China (English)

    孙立祥; 胡敏; 胡胜元; 潘长春

    2014-01-01

    Phagostimulants for killing termites are baits prepared with auxiliary agents including toxicants and preservatives. The pH values of the additives are different and affect the bait pH value. In the study Macrotermes barneyi were fed with baits prepared with water solutions having different pH values,and the ratio of water solution to base material was 3:10 with the control bait prepared with water solution having pH value 7. The results showed that bait pH values affected Macrotermes barneyi feeding on baits. Consumption by Macrotermes barneyi of baits prepared with water solutions having pH value ≤4 and ≥10 was significantly lower than that of the control bait. The water solution pH value range for preparation of baits suitable to be fed on by Macrotermes barneyi was 5~9.%灭杀白蚁诱剂是由饵料中添加毒剂和防腐剂等辅剂配制而成,这些添加成份酸碱度各不相同,并且影响饵料pH值。本研究用不同pH值水溶液配制饵料饲喂黄翅大白蚁,水溶液与基料比为3颐10,用pH值为7水溶液配制饵料作对照。试验结果表明,饵料基pH值影响黄翅大白蚁对饵料取食,溶液pH值臆4和逸10时所配制的饵料,黄翅大白蚁取食饵料量显著少于对照,适宜黄翅大白蚁取食的饵料配制溶液pH区间为5耀9。

  13. Influence of pH value on microstructure and thermal stability of Ni-P electroless coating prepared in acidic condition

    Institute of Scientific and Technical Information of China (English)

    Xiao Wei Zhou; Hui Ming Jin; Lin Nan Zhang

    2009-01-01

    Three kinds of Ni-P electroless coatings were prepared in nickel sulphate solution at different pH values of 4.5, 5.5 and 6.5 with the purpose of ascertaining the influence of pH value on microstructure, internal stress statue and thermal stability of the coatings. Laser curvature (LC) method was used to measure the residual stress level in the coatings. Scanning electronic microscopy (SEM) and transmission electronic microscopy with energy dispersive spectrum (TEM/EDS) were used to examine the surface morphology and internal phase structure of the coatings, respectively. Differential scanning calorimeter (DSC) was used to analyze the phase transformation and thermal stability of the coatings at high temperature. Results showed the Ni-P coating prepared at pH 5.5 with nanocrystal mixed in amorphous structure had the worst thermal stability. The relatively higher stability of Ni-P coatings prepared at pH 4.5 and 6.5 was ascribed to the lower tensile stress level and much finer grain size, respectively. Besides, inverse Hall-Petch effect of annealing strengthening might also contribute to the integrity of Ni-P coating prepared at pH 6.5.

  14. Changes in composition and enamel demineralization inhibition activities of gallic acid at different pH values

    NARCIS (Netherlands)

    Zhang, J.; Huang, X.; Huang, S.; Deng, M.; Xie, X.; Liu, M.; Liu, H.; Zhou, X.; Li, J.; ten Cate, J.M.

    2015-01-01

    Background. Gallic acid (GA) has been shown to inhibit demineralization and enhance remineralization of enamel; however, GA solution is highly acidic. This study was to investigate the stability of GA solutions at various pH and to examine the resultant effects on enamel demineralization. Methods. T

  15. Early effects of oral administration of lafutidine with mosapride compared with lafutidine alone on intragastric pH values

    Directory of Open Access Journals (Sweden)

    Koide Tomoko

    2009-07-01

    Full Text Available Abstract Background The ideal medication for treatment of acid related diseases should have a rapid onset of action to promote hemostasis and resolution of symptoms. The aim of our study was to investigate the inhibitory effects on gastric acid secretion after a single oral administrations of lafutidine, is a newly synthesized H2-receptor antagonist, with mosapride 5 mg or lafutidine alone. Methods Ten Helicobacter pylori negative male subjects participated in this randomized, two-way crossover study. Intragastric pH was monitored continuously for 4 hours after a single oral administration of lafutidine 10 mg or lafutidine 10 mg with mosapride 5 mg (the lafutidine being administrated one hour after the mosapride. Each administration was separated by a 7-day washout period. Results The average pH during the 4-hour period after administration of lafutidine 10 mg with mosapride 5 mg was higher than after lafutidine 10 mg alone (median: 5.25 versus 4.58, respectively; p = 0.0318. During the 3–4 hour study period, lafutidine 10 mg with mosapride 5 mg provided a higher pH, compared to lafutidine 10 mg alone (median: 7.28 versus 6.42; p = 0.0208. Conclusion In H. pylori negative healthy male subjects, an oral dose of lafutidine 10 mg with mosapride 5 mg more rapidly increased intragastric pH than lafutidine 10 mg alone.

  16. The influence of pH value and composition on the microstructure, magnetic properties of Co-Fe-Al Heusler nanoparticles

    Science.gov (United States)

    Yang, F. J.; Min, J. J.; Kang, Z. W.; Tu, S. Y.; Chen, H. B.; Liu, D. G.; Li, W. J.; Chen, X. Q.; Yang, C. P.

    2017-02-01

    Co-Fe-Al nanoparticles were synthesized by using a simple solution reduction method. The effects of pH value and atomic composition on the morphology, microstructure and magnetic properties of the prepared Co-Fe-Al nanoparticles were investigated. It was found that pure Co-Fe-Al phase with small particle size can be obtained at pH = 7.0 which have high saturation magnetization and low coercivity. Furthermore, the defects will increase with the increasing of Co composition in Co-Fe-Al nanoparticles which induce the deterioration of the B2 ordering, the abrupt decrease of magnetic moment and the abrupt increase of coercivity.

  17. Investigation of the adsorption of anionic surfactants at different pH values by means of active carbon and the kinetics of adsorption

    Directory of Open Access Journals (Sweden)

    SIBEL ZOR

    2004-01-01

    Full Text Available In this study, the effect of pH on the removal of anionic surfactants, such as linear alkyl benzene sulfonate (LABS and dodecyl benzene sulfonate (DBS by means of adsorption by activated carbon was investigated. For this purpose activated carbon was used as adsorbent. Anionic surfactant solutions with initial pH values of 3, 6, 8 and 12 were used. The adsorption isotherms for the adsorption of anionic surfactants by active carbon at different pH were determined. These adsorption isotherms were seen to be consistent with Freundlich’s adsorption isotherm. k and n constants were determined from Freundlich’s linear equation. Adsorption rate constants were determined from the obtained kinetic curves which were suitable for the first order of rate kinetics.

  18. Bicelle-based liquid crystals for NMR-measurement of dipolar couplings at acidic and basic pH values

    Energy Technology Data Exchange (ETDEWEB)

    Ottiger, Marcel; Bax, Ad [National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Laboratory of Chemical Physics (United States)

    1999-02-15

    It is demonstrated that mixtures of ditetradecyl- phosphatidylcholine or didodecyl-phoshatidylcholine and dihexyl- phosphatidylcholine in water form lyotropic liquid crystalline phases under similar conditions as previously reported for bicelles consisting of dimyristoyl-phosphatidylcholine (DMPC) and dihexanoyl- phosphatidylcholine (DHPC). The carboxy-ester bonds present in DMPC and DHPC are replaced by ether linkages in their alkyl analogs, which prevents acid- or base-catalyzed hydrolysis of these compounds. 15N-1H dipolar couplings measured for ubiquitin over the 2.3-10.4pH range indicate that this protein retains a backbone conformation which is very similar to its structure at pH 6.5 over this entire range.

  19. Effect of various pH values, ionic strength, and temperature on papain hydrolysis of salivary film.

    Science.gov (United States)

    Yao, Jiang-Wu; Xiao, Yin; Lin, Feng

    2012-04-01

    Stimulated human whole saliva (WS) was used to study the dynamics of papain hydrolysis at defined pH, ionic strength, and temperature with the view of reducing an acquired pellicle. A quartz crystal microbalance with dissipation (QCM-D) was used to monitor the changes in frequency caused by enzyme hydrolysis of WS films, and the hydrolytic parameters were calculated using an empirical model. The morphological and conformational changes of the salivary films before and after enzymatic hydrolysis were characterized by atomic force microscopy (AFM) imaging and grazing-angle Fourier transform infrared (GA-FTIR ) spectra, respectively. The characteristics of papain hydrolysis of WS films were pH-, ionic strength-, and temperature-dependent. The WS films were partially removed by the action of papain, resulting in thinner and smoother surfaces. The infrared data suggested that hydrolysis-induced deformation did not occur on the remnants of salivary films. The processes of papain hydrolysis of WS films can be controlled by properly regulating pH, ionic strength, and temperature.

  20. 酸碱度值对土体液、塑限的影响%EFFECTS OF PH VALUE ON LIQUID LIMIT AND PLASTIC LIMIT OF SOIL

    Institute of Scientific and Technical Information of China (English)

    师林; 朱大勇; 陈龙飞

    2011-01-01

    By using the method of soaking in laboratory,the change laws between the liquid limit,plastic limit and plasticity index of the polluted soil and the pH value were studied.The values of the liquid limit and plastic limit of the soil samples were measured before and after soaking in the hydrochloric acid and sodium hydroxide solution with respective pH value.Then,the change laws indicate that,with the pH value increasing,the liquid limit and the plasticity index increase while the plastic limit presents that both ends are big and the middle is small;when fixing the pH value,the liquid limit is increasing proportional to the time of soaking,while the plastic limit is diminishing.Finally,the reasons causing these change laws were analyzed.%采用室内浸泡方法,研究污染土的液、塑限以及塑性指数随酸碱度值的变化规律。用不同酸碱度值的盐酸和氢氧化钠溶液浸泡土样,测定浸泡前、后土样的液、塑限值,总结其变化规律。试验表明:随着酸碱度值的增大,液限和塑性指数逐渐增大而塑限呈现两端大中间小;在酸碱度值一定的情况下,随着浸泡时间的增长,土样有液限值逐渐减小、塑限值逐渐增大的趋势。最后,对上述变化的原因进行分析。

  1. Review for Calculation and Application of pH Value%关于pH值的计算及应用专题复习

    Institute of Scientific and Technical Information of China (English)

    郭进利

    2011-01-01

    pH value of liquor is widely applied into chemistry experiments. The calculation ot pH value is of more types and difficulties and students should pay more attention to the correct understanding of concepts and the systematical grasp of knowledge in learn%溶液的pH值在化学实验中有广泛的应用。有关pH值的计算类型多,难度大,在学习过程中要注意对概念的准确理解和知识的系统性掌握。本文对pH值的计算进行了较全面的总结。

  2. A model to explain high values of pH in an alkali sodic soil Modelo para explicar valores elevados de pH em um solo sódico alcalino

    Directory of Open Access Journals (Sweden)

    José Guerrero-Alves

    2002-12-01

    Full Text Available For alkali sodic soils (pH>8.5, the "hydrolysis of exchangeable sodium" has been used as a possible explanation for the alkalinity production and rise in pH of these soils. As an alternative to this hypothesis, a model was developed to simulate and to explain that the alkalinity production and rise in pH is possible in a soil that accumulates alkaline sodium salts and CaCO3. Several simulations were performed by using different combinations of CO2 partial pressures (P, presence or absence of MgCO3, along with experimental values of exchangeable sodium percentage (ESP and ion concentrations in saturation extracts from an alkali sodic soil (named Pantanal. A hypothetical system with similar conditions to the Pantanal soil but with a Gapon selectivity coefficient (KG of 0.01475 (mmol L-1-1/2 was also considered. Good agreement was obtained between experimental and predicted values for pH and ion concentrations in the soil solution when the model (without MgCO3 was applied to the Pantanal soil. However, KG values calculated for the Pantanal soil were generally higher than 0.01475 (mmol L-1-1/2. Moreover, high pH values and elevated ionic strength were obtained when a KG of 0.01475 (mmol L-1-1/2 was used at high ESP (similar to those found in the Pantanal soil. KG values obtained for the Pantanal soil and the results obtained in the simulation of the hypothetical system are suggesting that a value higher than 0.01475 (mmol L-1-1/2 should be used to adequately simulate the behavior of the Pantanal soil at low ionic strength and high ESP values.Em solos alcalino sódicos (pH>8,5, a "hidrólise de sódio trocável" tem sido usada como uma possível explicação para a produção de álcali e elevação do pH nestes solos. Como uma alternativa a essa hipótese, um modelo foi desenvolvido para simular e explicar que a produção de álcali e elevação do pH é possível num solo que acumula sais alcalinos de sódio e CaCO3. Várias simulações foram

  3. pH 值对原代大鼠肝细胞冻存效果的影响%Effect of pH Value for the Cryopreservation of Primary Rat Hepatocytes

    Institute of Scientific and Technical Information of China (English)

    付建柱; 张立军; 于则利

    2012-01-01

    To evaluate the effect of PH value for the cryopreservation of primary hepatocytes in different solutions. Methods Primary rat hepatocytes were cryopreserved with UW solution and RPMI 1640 solution containing 20% FBS with 12% DMSO. PH value of each solution was adjusted to7.1t 7.4, 7.7 respectively. After thawing the cryopreserved hepatocytes after 7, 14, 28 days, cell viability, MTT and Levels of released LDH were analyzed for each group. Results After 7, 14 and 28 days, hepatocytes cryopreserved in pH 7.4 and pH 7.7 were significantly better in all three terms than pH 7.1. Conclusion Alkalescent Medium environment might be more suitable environment for cryopreservation of rat hepatocytes.%目的 研究不同pH值的条件下原代大鼠肝细胞冻存的效果.方法 将大鼠肝细胞保存在含有20% FSB和12%DMSO的UW液和RPMI 1640液中,并把两种保存液的pH值调节成7.1、7.4、7.7.于冻存7、14、28天后进行复苏,使用存活率、MTT、LDH漏出浓度3项指标进行对比分析.结果 7天时,pH值7.4组的各项指标明显优于其他两组,14天和28天时,pH值7.7组与pH值7.4组均明显优于pH值7.1组.结论 pH值7.4和pH值7.7的保存效果优于pH值7.1,且随着时间的延长,差距有扩大的趋势,说明中性或略偏碱性环境更利于肝细胞的长期保存.

  4. Effects of gaseous ammonia on intracellular pH values in leaves of C 3- and C 4-plants

    Science.gov (United States)

    Yin, Zu-Hua; Kaiser, Werner; Heber, Ulrich; Raven, John A.

    Responses of cytosolic and vacuolar pH to different concentrations (1.3-5.4 μmol NH 3 mol -1 gas or 0.940-3.825 mg NH 3 m -3 gas) of gaseous NH 3 were studied in experiments of 3 h duration by recording changes in fluorescence of pyranine and esculin in leaves of C 3 and C 4 plants. After a lag phase of 0.5-4 min, the uptake of NH 3 at 50-200 nmol m -2 leaf area s -1 increased pyranine fluorescence, indicating cytosolic alkalinization in leaves of Pelargonium zonale L. (C 3) and Amaranthus caudatus L. (C 4). A smaller increase in esculin fluorescence induced by NH 3 indicated some vacuolar alkalization in a Spinacia oleracea L. leaf. Photosynthesis and transpiration remained unchanged during exposure of illuminated leaves to NH 3 for up to 30 min (the maximum tested). CO 2 concentrations influenced the extent of cytosolic alkalinization. 500 μmol CO 2 mol -1 gas suppressed the NH 3-induced cytosolic alkalinization relative to that found in 16 μmol CO 2 mol -1 gas. The suppressing effect of CO 2 on NH 3-induced alkalization was larger in illuminated leaves of the C 4Amaranthus than the C 3Pelargonium. These results indicate that the alkaline pH shift caused by solution and protonation of NH 3 in aqueous leaf compartments is affected by assimilation of NH 3.

  5. Effects of initial pH value of the medium on the alcoholic fermentation performance of Saccharomyces cerevisiae cells immobilized on nipa leaf sheath pieces

    Directory of Open Access Journals (Sweden)

    Hoang Duc Toan Le

    2014-12-01

    Full Text Available Immobilized yeast on nipa leaf sheath pieces was applied to ethanol fermentation using the medium with different initial pH values (5.1, 4.5, 4.0, and 3.5. Control samples with the free yeast were also carried out under the same conditions. Low pH value of 4.0 or 3.5 significantly reduced yeast growth and increased the residual sugar level in the fermentation broths for both the immobilized and free cells. In all cases, the ethanol content produced and ethanol formation rate of the immobilized yeast were 13-33% and 35-69%, respectively, higher than those of the free yeast. In addition, the residual sugar content in the immobilized yeast cultures was 2.1-20.5 times lower than that in the free yeast cultures. The yeast immobilized on nipa leaf stem pieces exhibited higher alcoholic fermentation performance than the free yeast in medium with low pH value. This support was potential for further research for application in ethanol industry.

  6. Differentiating calcium oxalate and hydroxyapatite stones in vivo using dual-energy CT and urine supersaturation and pH values.

    Science.gov (United States)

    Liu, Yu; Qu, Mingliang; Carter, Rickey E; Leng, Shuai; Ramirez-Giraldo, Juan Carlos; Jaramillo, Giselle; Krambeck, Amy E; Lieske, John C; Vrtiska, Terri J; McCollough, Cynthia H

    2013-12-01

    Knowledge of urinary stone composition can guide therapeutic intervention for patients with calcium oxalate (CaOx) or hydroxyapatite (HA) stones. In this study, we determined the accuracy of noninvasive differentiation of these two stone types using dual-energy CT (DECT) and urine supersaturation (SS) and pH values. Patients who underwent clinically indicated DECT scanning for stone disease and subsequent surgical intervention were enrolled. Stone composition was determined using infrared spectroscopy. DECT images were processed using custom-developed software that evaluated the ratio of CT numbers between low- and high-energy images. Clinical information, including patient age, gender, and urine pH and supersaturation profile, was obtained from electronic medical records. Simple and multiple logistic regressions were used to determine if the ratio of CT numbers could discriminate CaOx from HA stones alone or in conjunction with urine supersaturation and pH. Urinary stones (CaOx n = 43, HA n = 18) from 61 patients were included in this study. In a univariate model, DECT data, urine SS-HA, and urine pH had an area under the receiver operating characteristic curve of 0.78 (95% confidence interval [CI] 0.66-0.91, P = .016), 0.76 (95% CI 0.61-0.91, P = .003), and 0.60 (95% CI 0.44-0.75, P = .20), respectively, for predicting stone composition. The combination of CT data and the urinary SS-HA had an area under the receiver operating characteristic curve of 0.79 (95% CI 0.66-0.92, P = .007) for correctly differentiating these two stone types. DECT differentiated between CaOx and HA stones similarly to SS-HA, whereas pH was a poor discriminator. The combination of DECT and urine SS or pH data did not improve this performance. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  7. The influence of elevated CO2 on rain water PH value%CO2含量升高对雨水PH值的影响

    Institute of Scientific and Technical Information of China (English)

    孔慧敏; 龙慧艳

    2014-01-01

    正常雨水的PH值约为5.7左右。酸雨是指PH<5.6的降雨。本文利用化学平衡常数根据公式对雨水中的PH值进行了估算,并推导出CO2分压与ph值的关系,从理论上推导出CO2浓度升高会引起水中氢离子浓度的增大,从而最终导致雨水中ph值下降。指出当二氧化碳的浓度达到一定的浓度,人们将面对除温室效应以外的更深远的影响。%Normal rain PH of about 5.7 or so. Acid rain refers to PH < 5.6 of rain. This paper, by using the chemical equilibrium constant according to the formula to estimate, the PH of rain water and CO2 partial pressure and PH value is deduced, the relationship between elevated CO2 concentration is deduced theoretically will cause the increase of hydrogen ion concentration in water, which eventually led to the decrease of the PH in the rain. Pointed out that when the concentration of carbon dioxide reaches a certain concentration, people will face a more profound influence on other than the greenhouse effect.

  8. Observing Effects of Calcium/Magnesium Ions and pH Value on the Self-Assembly of Extracted Swine Tendon Collagen by Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Xuan Song

    2017-01-01

    Full Text Available Self-assembly of extracted collagen from swine trotter tendon under different conditions was firstly observed using atomic force microscopy; then the effects of collagen concentration, pH value, and metal ions to the topography of the collagen assembly were analyzed with the height images and section analysis data. Collagen assembly under 0.1 M, 0.2 M, 0.3 M CaCl2, and MgCl2 solutions in different pH values showed significant differences (P < 0.05 in the topographical properties including height, width, and roughness. With the concentration being increased, the width of collagen decreased significantly (P < 0.05. The width of collagen fibers was first increased significantly (P < 0.05 and then decreased with the increasing of pH. The collagen was assembled with network structure on the mica in solution with Ca2+ ions. However, it had shown uniformed fibrous structure with Mg2+ ions on the new cleaved mica sheet. In addition, the width of collagen fibrous was 31~58 nm in solution with Mg2+ but 21~50 nm in Ca2+ solution. The self-assembly collagen displayed various potential abilities to construct fibers or membrane on mica surfaces with Ca2+ ions and Mg2+ irons. Besides, the result of collagen self-assembly had shown more relations among solution pH value, metal ions, and collagen molecular concentration, which will provide useful information on the control of collagen self-assembly in tissue engineering and food packaging engineering.

  9. Analyzing Ph value, energy and phospholipid metabolism of various cerebral tumors and normal brain tissue with 31P magnetic resonance spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Wei Tan; Guangyao Wu; Junmo Sun

    2006-01-01

    BACKGROUND: 31P magnetic resonance spectroscopy (31P MRS) can be used to non-injuredly and dynamicly detect various metabolites including phosphorus in organis and reflect changes of phospholipid metabolism and energy metabolism in tissue and pH value in cells.OBJECTIVE: To observe changes of pH value, phospholipid metabolism and energy metabolism of various cerebral tumors and normal brain tissue with 31P MRS.DESIGN: Semi-quantitative contrast observation.PARTICIPANTS: A total of 44 patients with cerebral tumor diagnosed with surgery operation were selected from the Department of Magnetic Resonance, Central South Hospital, Wuhan University from September 2004 to June 2006. All the subjects had complete 31P MRS data before steroid and operation. Among them,16 patients had glioma of grade Ⅱ-Ⅲ, 12 spongioblastoma and 16 meningioma. The mean age was (45±6)years. Another 36 subjects without focus on cerebral MRI were regarded as normal group, including 19 males and 18 females, and the mean age was (41±4) years. Included subjects were consent.METHODS: Eclipse1.5T MRS (Philips Company) was used to collect wave spectrum; jMRUI(1.3) was used to analyze experimental data and calculate pH value in voxel and ratios of phosphocreatine (PCr)/inorganic phosphate (Pi), PCr/phosphodiesterase (PDE) and phosphomonoesterase (PME)/β-adenosine triphosphate (β-ATP) of various metabolites. 31P MRS results were compared with t test between tumor patients and normal subjects.MAIN OUTCOME MEASURES: Changes of phospholipid metabolism (PME/PDE), energy metabolism (PCr/ATP) and pH value of various cerebral tumors and normal brain tissues.RESULTS: A total of 44 cases with cerebral tumor and 36 normal subjects were involved in the final analysis. pH value and semi-quantitative measurements of normal brain tissues and various cerebral tumors: ① pH value at top occipital region and temple occipital region of normal brain tissue was 7.04±0.02;PCt/β-ATP was 1.51 ±0.03; PCt/Pi was 2.85

  10. 堆叠pH值对Mozzarella干酪熔化特性的影响%Effect of Milling pH Value on Mozzarella Cheese Meltability

    Institute of Scientific and Technical Information of China (English)

    郭媛; 郭慧媛; 王芳; 万长江; 姜鹭; 任发政

    2011-01-01

    研究了堆叠pH值对Mozzarella干酪熔化性的影响.通过考察不同堆叠pH值Mozzarella干酪贮藏1~7周的熔化性、可冻结水含量、pH值4.6可溶性氮含量、Urea-PAGE电泳,利用共聚焦激光扫描电镜、差示热量扫描仪、流变仪,探讨了堆叠pH值与Mozzarella干酪熔化特性的联系.结果表明,低堆叠pH值的Mozzarella干酪样品可冻结水含量低,结合水含量高,随贮藏期延长(21 d以上)蛋白水解片段增多,形成的纤维状结构更加有序,相应的熔化性更好.%The effect of different milling pH value on cheese meltability was studied. Combined with confocal laser scanning spectroscopy, DSC and rheometer techniques, meltability, freezable water content, pH 4. 6-soluble protein and Urea-PAGE were analyzed during 1 ~ 7 weeks storages. Results showed that Mozzarella cheese with a low milling pH value had less freezable water and more binding water. When the storage prolonged (more than 21 d) , protein degradation increased, and better meltability was achieved.

  11. Investigation on Soil pH Value in Tobacco Field in Zhuxi County%竹溪县烟田土壤酸碱度调查

    Institute of Scientific and Technical Information of China (English)

    杨继龙; 刘阳; 王远林; 王官明; 张良培; 张晓亮; 张凯

    2016-01-01

    Objective] To study the status of soil pH value of tobacco field in Zhuxi city, and to put forward the improving measures.[ Meth-od] The soil pH values of 817 fields belonging to 587 tobacco families of 38 villages in 5 towns were measured.[ Result] The county average soil pH value was 6.30, the maximum value was 8.5, the minimum value was 5.0.The pH values of 579 samples were all lower than 6.5, which accounted for 70.9% and indicated that the most of the tested soil samples were the weak acid.Soil pH values of 736 samples were be-tween 5.0 to 7.0, which was suitable for the tobacco growth, and accounted for more than 90.09%.[Conclusion] The soil pH value of to-bacco fields is mainly weak acidity in Zhuxi County.There is acidification phenomenon in soil at present, but it is not serious.Zhuxi County is still the suitable production area for high-quality flue-cured tobacco by carrying out the sustained increase of organic fertilizer, planting green manure, crop rotation, replacing potassium sulfate by potassium nitrate.%[目的]调查竹溪县烟叶种植田间土壤酸碱度的现状,提出相应的改良措施。[方法]对全县5个乡镇38个行政村583户烟农的817个田块进行检测。[结果]全县土壤pH平均值为6.30,最大值为8.5,最小值为5.0,pH在6.5以下的样本数579个,占比70.9%,整体呈弱酸性。适宜烤烟生长的土壤样本(pH 5.5~7.0)有736个,占比90.09%。[结论]竹溪县烟田土壤以弱酸性(pH 5.5~6.5)为主。当前土壤酸化现象并不严重,通过持续开展增施有机肥、种植绿肥、轮作、硝酸钾替代硫酸钾等改良措施,竹溪县仍为适宜生产优质烤烟的区域。

  12. Effect of weak acid preservatives on growth of bakery product spoilage fungi at different water activities and pH values.

    Science.gov (United States)

    Suhr, K I; Nielsen, P V

    2004-08-15

    Inhibition of spoilage organisms from bakery products by weak acid preservatives in concentrations of 0%, 0.003%, 0.03% and 0.3% (w/v) was investigated experimentally on a substrate media with water activity (a(w)) and pH ranging from sourdough-fermented acidic rye bread to alkaline intermediate moisture sponge cake types (a(w) 0.80-0.95, pH 4.7-7.4). Initially, rye bread conditions (a(w) 0.94-0.97 and pH 4.4-4.8) in combination with calcium propionate were investigated. Results showed that the highest concentration of propionate (0.3%) at all conditions apart from high a(w) (0.97) and high pH (4.8) totally inhibited fungal growth for a 2-week period, with the exception of Penicillium roqueforti, Penicillium commune and Eurotium rubrum. Characteristically for the major spoiler of rye bread, P. roqueforti, all three isolates tested were stimulated by propionate and the stimulation was significantly enhanced at high water activity levels. The effect of propionate on production of secondary metabolites (mycophenolic acid, rugulovasine, echinulin, flavoglaucin) was also studied, and variable or isolate dependent results were found. Subsequently, a screening experiment representing a wider range of bakery products was conducted using calcium propionate, potassium sorbate and sodium benzoate. The obtained data was modelled using survival analysis to determine 'spoilage-free time' for the fungi. At the low a(w) level (0.80) only Eurotium species grew within the test period of 30 days. Higher water activity levels as well as higher pH values decreased spoilage-free times of the fungi. The preservative calcium propionate was less effective than potassium sorbate and sodium benzoate.

  13. Effect of solution pH value changes on fluorescence intensity of magnetic-luminescent Fe3O4@Gd2O3:Eu3+ nanoparticles

    Institute of Scientific and Technical Information of China (English)

    吴拓; 潘桦滟; 陈如标; 罗东; 张宏; 沈晔; 李旸晖; 王乐

    2016-01-01

    In this paper, bifunctional Fe3O4@Gd2O3:Eu3+ core-shell nanoparticles with both magnetic and fluorescent properties were synthesized through a urea homogeneous precipitation (UHP) method. Particular emphasis was placed on investigating the influence of the solution pH value on the photoluminescence of the core-shell nanocomposites. It showed that the samples treated at the solution of pH=3.0 had the highest luminescence due to the enhanced crystallinity and size uniformity of nanoparticles. The Fe3O4@Gd2O3:Eu3+ nanocomposites exhibited an almost spherical shape with a mean diameter of 60 nm, and had strong red emis-sions of Eu3+ at 612 nm as well as good magnetization with the saturation magnetization of 1.29 emu/g. It thus indicated that the core-shell nanocomposites investigated has great potential in biomedical applications.

  14. The effects of work-related values on communication between R and D groups, part 1. Ph.D. Thesis

    Science.gov (United States)

    Douds, C. F.

    1970-01-01

    The research concerned with the liaison, interface, coupling, and technology transfer processes that occur in research and development is reported. Overviews of the functions of communication and coupling in the R and D processes, and the theoretical considerations of coupling, communication, and values are presented along with descriptions of the field research program and the instrumentation.

  15. VARIABILITY OF CONTINUOUSLY MEASURED ARTERIAL PH AND BLOOD-GAS VALUES IN THE NEAR-TERM FETAL LAMB

    NARCIS (Netherlands)

    WOUDSTRA, BR; DEWOLF, BTHM; SMITS, TM; NATHANIELSZ, PW; ZIJLSTRA, WG; AARNOUDSE, JG

    1995-01-01

    In fetal sheep, arterial blood gas values show considerable spontaneous fluctuations. The aim of the present study was to obtain quantitative data on fetal blood gas variability. Accurate assessment of the intraindividual variations can hardly be obtained from intermittent blood samples, but require

  16. 尿液pH值与代谢综合征的相关性研究%Correlation between urinary pH value and metabolic syndrome

    Institute of Scientific and Technical Information of China (English)

    陈颖; 宁光; 杨枝; 黄飞; 王天歌; 李勉; 徐敏; 徐瑜; 毕宇芳; 陆洁莉

    2012-01-01

    Objective To investigate the correlation between urinary pH value and metabolic syndrome in middle-aged and elderly Chinese people. Methods Two thousand three hundred and twenty-two subjects aged 40 years or older from Jiading community, Shanghai, were enrolled in this study. Questionnaire interview, physical examination, and blood biochemical tests including blood glucose, lipids, insulin, liver function tests, renal function tests and urinary pH value were performed or measured. Multivariate linear regression analyses was performed to investigate the correlation between urinary pH value and metabolic syndrome. Logistic multiple regression analysis was performed to explore the risk of metabolic syndrome for decreased urinary pH value. The metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel HI (NCEP ATP HI) criteria with modification appropriate for Asian population. Results Subjects with metabolic syndrome had higher waist circumference, body mass index, systolic blood pressure, serum fasting glucose, low-density lipoprotein-cholesterol,triglycerides and lower high-density lipoprotein-cholesterol, urinary pH value than subjects without metabolic syndrome. Pearson's correlation analysis indicated that urinary pH value was negatively correlated with waist circumference, triglycerides, insulin resistance index and positively correlated with high-density lipoprotein-cholesterol. With the increase in components of metabolic syndrome, urinary pH value decreased both in men and women (P for trend<0.001). logistic regression analysis indicated that central obesity, hypertriglycerides, hypertension and hyperglycemia were the influencing factors of low urinary pH value. Subjects with metabolic syndrome had higher risk of having decreased urinary pH value [odds ratio (OR) = 1.42;95% confidence interval (CI): 1.19-1.70]. Conclusions Metabolic syndrome is associated with decreased urinary pH value in middle-aged and

  17. Cadmium availability in rice paddy fields from a mining area: The effects of soil properties highlighting iron fractions and pH value.

    Science.gov (United States)

    Yu, Huan-Yun; Liu, Chuanping; Zhu, Jishu; Li, Fangbai; Deng, Dong-Mei; Wang, Qi; Liu, Chengshuai

    2016-02-01

    Cadmium (Cd) availability can be significantly affected by soil properties. The effect of pH value on Cd availability has been confirmed. Paddy soils in South China generally contain high contents of iron (Fe). Thus, it is hypothesized that Fe fractions, in addition to pH value, may play an important role in the Cd bioavailability in paddy soil and this requires further investigation. In this study, 73 paired soil and rice plant samples were collected from paddy fields those were contaminated by acid mine drainage containing Cd. The contents of Fe in the amorphous and DCB-extractable Fe oxides were significantly and negatively correlated with the Cd content in rice grain or straw (excluding DCB-extractable Fe vs Cd in straw). In addition, the concentration of HCl-extractable Fe(II) derived from Fe(III) reduction was positively correlated with the Cd content in rice grain or straw. These results suggest that soil Fe redox could affect the availability of Cd in rice plant. Contribution assessment of soil properties to Cd accumulation in rice grain based on random forest (RF) and stochastic gradient boosting (SGB) showed that pH value should be the most important factor and the content of Fe in the amorphous Fe oxides should be the second most important factor in affecting Cd content in rice grain. Overall, compared with the studies from temperate regions, such as Europe and northern China, Fe oxide exhibited its unique role in the bioavailability of Cd in the reddish paddy soil from our study area. The exploration of practical remediation strategies for Cd from the perspective of Fe oxide may be promising. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. What do I want to be with my PhD? The roles of personal values and structural dynamics in shaping the career interests of recent biomedical science PhD graduates.

    Science.gov (United States)

    Gibbs, Kenneth D; Griffin, Kimberly A

    2013-01-01

    Interest in faculty careers decreases as graduate training progresses; however, the process underlying career-interest formation remains poorly defined. To better understand this process and whether/how it differs across social identity (i.e., race/ethnicity, gender), we conducted focus groups with 38 biomedical scientists who received PhDs between 2006 and 2011, including 23 women and 18 individuals from underrepresented minority (URM) backgrounds. Objective performance and quality of advisor relationships were not significantly different between scientists with high versus low interest in faculty careers. Career interests were fluid and formed in environments that generally lacked structured career development. Vicarious learning shaped similar outcome expectations about academic careers for all scientists; however, women and URMs recounted additional, distinct experiences and expectations. Scientists pursuing faculty careers described personal values, which differed by social identity, as their primary driver. For scientists with low interest in faculty careers, a combination of values, shared across social identity, and structural dynamics of the biomedical workforce (e.g., job market, grant funding, postdoc pay, etc.) played determinative roles. These findings illuminate the complexity of career choice and suggest attracting the best, most diverse academic workforce requires institutional leaders and policy makers go beyond developing individual skill, attending to individuals' values and promoting institutional and systemic reforms.

  19. Effect of weak acid preservatives on growth of bakery product spoilage fungi at different water activities and pH values

    DEFF Research Database (Denmark)

    Suhr, Karin Isabel; Nielsen, Per Væggemose

    2004-01-01

    of bakery products was conducted using calcium propionate, potassium sorbate and sodium benzoate. The obtained data was modelled using survival analysis to determine 'spoilage-free time' for the fungi. At the low a(w) level (0.80) only Eurotium species grew within the test period of 30 days. Higher water...... activity levels as well as higher pH values decreased spoilage-free times of the fungi. The preservative calcium propionate was less effective than potassium sorbate and sodium benzoate....

  20. Specific detection of cysteine and homocysteine in biological fluids by tuning the pH values of fluorosurfactant-stabilized gold colloidal solution.

    Science.gov (United States)

    Xiao, Qunyan; Shang, Fei; Xu, Xuechen; Li, Qianqian; Lu, Chao; Lin, Jin-Ming

    2011-12-15

    This study describes the use of 14 nm nonionic fluorosurfactant-capped gold nanoparticles (FSN-capped AuNPs) for the simultaneous detection of cysteine (Cys) and homocysteine (Hcy) using colorimetric method, requiring no use of separation techniques. It was found that the kinetics of Cys/Hcy-induced aggregation of the 14 nm FSN-capped AuNPs strongly depends on the pH value of gold colloidal solution. At a pH of 6.5, the Cys-induced aggregation kinetics of the FSN-capped AuNPs was almost identical to that induced by Hcy, facilitating simultaneous detection of total Cys and Hcy up to a concentration as low as 0.15 μM; while at pH 12.0, the kinetics of Cys-induced aggregation was much faster than that inducted by Hcy, leading to selective detection of Cys at concentration as low as 1.0 μM in the presence of Hcy. The applicability of the method was validated by spiking known amount of Cys and Hcy in human urine and plasma samples, obtaining a recovery of 95.4-105.5%. The present approach is simple, high selective and provides high reproducibility, and has a great potentiality in disease diagnosis.

  1. Metal accumulation and oxidative stress biomarkers in liver of freshwater fish Carassius auratus following in vivo exposure to waterborne zinc under different pH values.

    Science.gov (United States)

    Qu, Ruijuan; Feng, Mingbao; Wang, Xinghao; Qin, Li; Wang, Chao; Wang, Zunyao; Wang, Liansheng

    2014-05-01

    In this study, laboratory experiments were conducted to investigate the combined effect of zinc and pH on metal accumulation and oxidative stress biomarkers in Carassius auratus. Fish were exposed to 0.1 and 1.0mg Zn/L at three pH values (5.0, 7.25, 9.0) for 3, 12, and 30 d. After each exposure, the contents of three trace elements (Zn, Fe and Cu) were determined in liver. Generally, longer exposure to zinc (12d and 30 d) increased hepatic Zn and Cu deposition, but decreased Fe content. Increasing accumulation of Zn in the tissue was also observed with increasing zinc concentration in the exposure medium. Moreover, hepatic antioxidant enzyme activities including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), together with the level of glutathione (GSH) were measured to evaluate the oxidative stress status. The decreases in the four measured biochemical parameters after 3d exposure might reflect the failure of the antioxidant defense system in neutralizing the ROS generated during the metabolic process, while the recovery of the antioxidants at days 12 and 30 suggested a possible shift toward a detoxification mechanism. With regard to the influence of pH on zinc toxicity, the general observation was that the living environment became more stressful when the water conditions changed from an acidic state toward a near-neutral or alkaline state.

  2. Enzyme-regulated the changes of pH values for assembling a colorimetric and multistage interconnection logic network with multiple readouts

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yanyan; Ran, Xiang; Lin, Youhui [Laboratory of Chemical Biology, Division of Biological Inorganic Chemistry, State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022 (China); Graduate School of University of Chinese Academy of Sciences, Beijing 100039 (China); Ren, Jinsong, E-mail: jren@ciac.ac.cn [Laboratory of Chemical Biology, Division of Biological Inorganic Chemistry, State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022 (China); Qu, Xiaogang [Laboratory of Chemical Biology, Division of Biological Inorganic Chemistry, State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022 (China)

    2015-04-22

    Highlights: • A colorimetric and multistage biological network has been developed. • This system was on the basis of the enzyme-regulated changes of pH values. • This enzyme-based system could assemble large biological circuit. • Two signal transducers (DNA/AuNPs and acid–base indicators) were used. • The compositions of samples could be detected through visual output signals. - Abstract: Based on enzymatic reactions-triggered changes of pH values and biocomputing, a novel and multistage interconnection biological network with multiple easy-detectable signal outputs has been developed. Compared with traditional chemical computing, the enzyme-based biological system could overcome the interference between reactions or the incompatibility of individual computing gates and offer a unique opportunity to assemble multicomponent/multifunctional logic circuitries. Our system included four enzyme inputs: β-galactosidase (β-gal), glucose oxidase (GOx), esterase (Est) and urease (Ur). With the assistance of two signal transducers (gold nanoparticles and acid–base indicators) or pH meter, the outputs of the biological network could be conveniently read by the naked eyes. In contrast to current methods, the approach present here could realize cost-effective, label-free and colorimetric logic operations without complicated instrument. By designing a series of Boolean logic operations, we could logically make judgment of the compositions of the samples on the basis of visual output signals. Our work offered a promising paradigm for future biological computing technology and might be highly useful in future intelligent diagnostics, prodrug activation, smart drug delivery, process control, and electronic applications.

  3. Hybrid hard- and soft-modeling of spectrophotometric data for monitoring of ciprofloxacin and its main photodegradation products at different pH values

    Science.gov (United States)

    Razuc, Mariela; Garrido, Mariano; Caro, Yamile S.; Teglia, Carla M.; Goicoechea, Héctor C.; Fernández Band, Beatriz S.

    2013-04-01

    A simple and fast on line spectrophotometric method combined with a hybrid hard-soft modeling multivariate curve resolution (HS-MCR) was proposed for the monitoring of photodegradation reaction of ciprofloxacin under UV radiation. The studied conditions attempt to emulate the effect of sunlight on these antibiotics that could be eventually present in the environment. The continuous flow system made it possible to study the ciprofloxacin degradation at different pH values almost at real time, avoiding errors that could arise from typical batch monitoring of the reaction. On the base of a concentration profiles obtained by previous pure soft-modeling approach, reaction pathways have been proposed for the parent compound and its photoproducts at different pH values. These kinetic models were used as a constraint in the HS-MCR analysis. The kinetic profiles and the corresponding pure response profile (UV-Vis spectra) of ciprofloxacin and its main degradation products were recovered after the application of HS-MCR analysis to the spectra recorded throughout the reaction. The observed behavior showed a good agreement with the photodegradation studies reported in the bibliography. Accordingly, the photodegradation reaction was studied by high performance liquid chromatography coupled with UV-Vis diode array detector (HPLC-DAD). The spectra recorded during the chromatographic analysis present a good correlation with the ones recovered by UV-Vis/HS-MCR method.

  4. pH value manipulated phase transition, microstructure evolution and tunable upconversion luminescence in Yb(3+)-Er(3+) codoped LiYF4/YF3 nanoparticles.

    Science.gov (United States)

    Ye, Song; Hu, Rongxuan; Jiang, Nan; Wang, Huiyun; Wang, Deping

    2015-09-21

    The pH value plays an important role in controlling the crystallization process and microstructure of the final products in the synthesis of nanocrystals with a solvothermal method. This work reported the effect of the mother solution pH value on the precipitation of LiYF4 and YF3 nanoparticles, as well as the microstructure evaluation of YF3 from a bowknot-like to spindle-like shape. Spectroscopy study suggests that there is strong correlation between the upconversion emission properties of the Yb(3+)-Er(3+) couple and the phase and the microstructure of the host. The strongest emissions and lowest red-to-green ratio are observed in the bowknot-like YF3 nanocrystals with the largest open ends. Further spectral investigation indicates that the phase and microstructure dependent upconversion properties are associated with the upconversion efficiency. The present study is of great importance in the design and synthesis of rare earth ion doped nanocrystals with tunable upconversion properties.

  5. Ultimate pH values and bacteriological condition of meat and stress metabolites in blood of transported reindeer bulls

    Directory of Open Access Journals (Sweden)

    E. Wiklund

    2001-03-01

    Full Text Available Twenty-three reindeer bulls, aged 2-3 years, fed during two winter months at the Vuolda reindeer research station in Arjeplog, Sweden, were used in the study. The first group of eight reindeer was moved from their feeding corral to a selection corral, captured by lasso and stunned with a captive bolt outside the selection corral. The second group of seven reindeer was moved to the selection corral, captured by lasso and restrained, after which they were loaded onto a lorry- and transported for 1 hour and then slaughtered. The third group of eight reindeer was moved to the selection corral and herded directly onto the lorry, without any manual handling. They were transported for 5 h and then slaughtered. In both transport groups, four reindeer were fitted with pre-programmed automatic blood sampling equipment (ABSE. ABSE sampled blood at predetermined times via a jugular vein catheter. Ultimate pH-values in three muscles (Mm. longissimus, triceps brachii and biceps femoris were significantly lower in the group carefully handled and transported for 5 h compared with the other two groups. The physiological mechanisms behind these results are discussed. Samples from M. semimembranosus were collected at slaughter and after 2, 6 and 10 days of refrigerated storage (+4 °C. The samples were analysed for total counts of aerobic bacteria (pour-plated in Tryptone Glucose Extract Agar, Difco, incubated at 20 °C and 30 °C, respectively for 72 h, coliform bacteria 37 °C (pour-plated in Violet Red Bile Agar, Oxoid, incubated at 37 °C for 24 h, Enterococci (surface-plated onto Slantez and Bartley Agar, Oxoid, incubated at 44 °C for 48 h and Bacillus cereus (surface-plated onto Blood Agar Plates (Blood Agar Base, Difco, supplemented with 5% defibrinated horse blood 30 °C for 24 h. All samples fell in the range 'fit for consumption'. At slaughter, there was no difference in ASAT activity, urea and Cortisol concentrations between the two transported groups

  6. Enzyme-regulated the changes of pH values for assembling a colorimetric and multistage interconnection logic network with multiple readouts.

    Science.gov (United States)

    Huang, Yanyan; Ran, Xiang; Lin, Youhui; Ren, Jinsong; Qu, Xiaogang

    2015-04-22

    Based on enzymatic reactions-triggered changes of pH values and biocomputing, a novel and multistage interconnection biological network with multiple easy-detectable signal outputs has been developed. Compared with traditional chemical computing, the enzyme-based biological system could overcome the interference between reactions or the incompatibility of individual computing gates and offer a unique opportunity to assemble multicomponent/multifunctional logic circuitries. Our system included four enzyme inputs: β-galactosidase (β-gal), glucose oxidase (GOx), esterase (Est) and urease (Ur). With the assistance of two signal transducers (gold nanoparticles and acid-base indicators) or pH meter, the outputs of the biological network could be conveniently read by the naked eyes. In contrast to current methods, the approach present here could realize cost-effective, label-free and colorimetric logic operations without complicated instrument. By designing a series of Boolean logic operations, we could logically make judgment of the compositions of the samples on the basis of visual output signals. Our work offered a promising paradigm for future biological computing technology and might be highly useful in future intelligent diagnostics, prodrug activation, smart drug delivery, process control, and electronic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Sensory meat quality, ultimate pH values, blood metabolites and carcass parametersin reindeer (Rangifer tarandus tarandus L. fed various diets

    Directory of Open Access Journals (Sweden)

    Eva Wiklund

    2000-03-01

    Full Text Available This investigation was made to study and compare the effects of different diets on sensory meat quality and ultimate pH values in reindeer muscles and to relate stress-induced blood metabolites and carcass parameters to the meat quality traits measured. Altogether 23 female reindeer calves were included in the study. During an adaptation period, all reindeer were allowed free access to a mimicked natural diet containing 80% lichens (lichen diet. On January 28, 8 reindeer (group Cjan were slaughtered. Five reindeer (group C.Mar were allowed continuous free access to the lichen diet throughout the experiment. During 8 days, the other reindeer (groups PL and PS were given the lichen diet, half of the amount offered to the control group, and were then starved for one day. Thereafter, these reindeer were fed 80% commercial reindeer feed (pellets and either 20% lichens (group PL, or 20% silage (group PS for 5 weeks. After this, all animals were slaughtered. The average carcass weight and dressing percentage in the group fed commercial reindeer feed and lichens (PL were higher than in group CMar- Fat registrations were generally higher in groups PL and PS than in the groups Cj2n and CMar- Ultimate pH values in M. triceps brachii and M. longissimus were significantly lower in the group CMST than in PL. The levels of all blood metabolites (urea, ASAT and Cortisol were generally higher in groups PL and PS than in groups Cja„ and CMEF- NO significant differences were found in any of sensory attributes of the meat (monitored according to ISO standards. The present study shows that muscle and fat depots in reindeer can be improved by feeding a diet based on reindeer pellets but suggests that a feeding period of 35 days might be too short to affect the sensory properties of reindeer meat.

  8. [Influences of the mobile phase constitution, salt concentration and pH value on retention characters of proteins on the metal chelate column].

    Science.gov (United States)

    Li, R; Di, Z M; Chen, G L

    2001-09-01

    The effects of the nature and concentration of salts, pH value and competitive eluent in the mobile phase on the protein retention have been systematically investigated. A mathematical expression describing the protein retention in metal chelate chromatography has been derived. It is proposed that the eluting power of the salt solution can be expressed by the eluent strength exponent epsilon. According to the retention characters of protein under different chromatographic conditions, the interaction between the various metal chelate ligands and proteins is discussed. The protein retention on the metal chelate column is a cooperative interactions of coordination, electrostatic and hydrophobic interaction. For the strong combined metal column with proteins such as IDA-Cu, the coordination is the most important, and the electrostatic interaction is secondary in chromatographic process. However, for the weak combined metal columns with proteins such as IDA-Ni, IDA-Co and IDA-Zn, the electrostatic interaction between the metal chelate ligands and proteins is the chief one, while the coordination is the next in importance. When the mobile phase contains high concentration of salt which can't form complex with the immobilized metal, the hydrophobic interaction between the protein and stationary phase will be increased. As the interaction between the metal chelate ligand and proteins relates to chromatographic operating conditions closely, different elution processes may be selected for different metal chelate columns. The gradient elution is generally performed by the low concentration of salt or different pH for weakly combined columns with proteins, however the competitive elution procedure is commonly utilized for strongly combined column. The experiment showed that NH3 is an excellent competitive eluent. It isn't only give the efficient separation of proteins, but also has the advantages of cheapness, less bleeding of the immobilized metals and ease of controlling NH3

  9. Effects of different pH values on seedling morphology and physiological characteristics of Vetiveria zizanioides under hydroponic culture%水培条件下不同 pH 值对香根草幼苗形态和生理特性的影响

    Institute of Scientific and Technical Information of China (English)

    王青青; 周强; 於丙军

    2014-01-01

    part of leaf apexes with a little chlorosis and root morphology without obvious change except color under conditions of weak alkalinity ( pH 9. 0 and pH 8. 0) and weak acidity (pH 5. 0 and pH 4. 0). With pH value of solution increasing ( alkalinity increasing) or decreasing (acidity increasing), both leaf water content and chlorophyll content decrease gradually and are lower than those of the control (pH 6. 5), while both relative electrolytic leakage and MDA content increase gradually and are higher than those of the control. In general, there are significant (P0. 05) difference in all indexes under conditions of weak alkalinity (pH 9. 0 and pH 8. 0) and weak acidity (pH 5. 0 and pH 4. 0) with the control. With pH value of solution increasing ( alkalinity increasing ) or decreasing ( acidity increasing), both the maximum root length and root activity decrease gradually. Under conditions of weak alkalinity (pH 8. 0) and weak acidity (pH 5. 0), the maximum root length is slightly lower than that of the control and root activity is slightly higher than that of the control without significant difference. Under pH 9. 0-pH 11. 0 and pH 4. 0-pH 2. 0, both the maximum root length and root activity are significantly lower than those of the control, in which root length is the shortest and root activity is the smallest under pH 11. 0, with 60. 50% and 9. 52% of the control,respectively. It is suggested that V. zizanioides has a wide adaptation range to acidity-alkalinity of soil, and can adapt soil habitat with pH 4. 0-pH 9. 0.

  10. Observation of pH Value in Electrokinetic Remediation using various electrolyte (MgSO4, KH2PO4 and Na(NO3)) for Barren Acidic Soil at Ayer Hitam, Johor, Malaysia

    Science.gov (United States)

    Norashira, J.; Zaidi, E.; Aziman, M.; Saiful Azhar, A. T.

    2016-07-01

    Barren acidic soil collected at Ayer Hitam, Johor Malaysia was recorded at pH value of 2.36 with relative humidity of 86%. This pH value is not suitable for the growth of any plants especially for the soil stabilization purposes. Gradation weathering within the range of 4 to 6 indicates an incomplete/partial weathering process. The soil grade in this range is known as a black shale mudstone. Beside, this also influences to a factor of the high surface water runoff at this particular soil species. As the acidic pH become a major problem for soil fertilizing hence an appropriate technique was implemented known as using ‘Electrokinetic Remediation’, EKR. This technique has a great potential in changing the soil pH value from acidic to less acidic and also kept maintain the pH at the saturated rate of electrochemical process. This research study presents the monitoring data of pH value due to the effect of various electrolyte consist of 0.5M of MgSO4, KH2PO4, and Na(NO3). Here, the distilled water (DW) was used as reference solution. The electric field was provided by dipping two pieces of identical rectangular aluminum foil as anode and cathode. The EKR was conducted under a constant voltage gradient of 50 V/m across the sample bulk at 0.14 m length measured between both electrodes. The data collection was conducted during the total period of 7 days surveillance. The variation of pH values at the remediation area between anode and cathode for various type of electrolyte indicates that there are a significant saturated value as it reaches 7 days of treatment. During the analysis, it is found that the highest pH value at the remediation area after 7 days treatment using Na(NO3), KH2PO4 and MgSO4 was 3.93, 3.33 and 3.39 respectively. Hence from the last stage of pH value observation, it can be conclude that the best electrolyte for barren soil treatment is Na(NO3) whereby it contribute to highest pH value and turn the soil to be less acidic.

  11. Glucose intolerance in dairy goats with pregnancy toxemia: Lack of correlation between blood pH and beta hydroxybutyric acid values.

    Science.gov (United States)

    Lima, Miguel S; Cota, João B; Vaz, Yolanda M; Ajuda, Inês G; Pascoal, Rita A; Carolino, Nuno; Hjerpe, Charles A

    2016-06-01

    This study assessed the response to a glucose tolerance test in dairy goats with pregnancy toxemia (PT), in healthy, pregnant, non-lactating dairy goats in the last month of gestation (HP), and in healthy, lactating, non-pregnant, dairy goats in mid-lactation (HL). A 500 mL volume of a 5% glucose solution was administered by the IV route. Blood glucose concentrations returned to pre-infusion levels by 90 min in all 8 HL goats, and by 180 min in all 8 HP goats. In contrast, concentrations of blood glucose were still significantly above pre-infusion levels at 180 min post-infusion in all 8 PT goats. Thus, marked glucose intolerance was demonstrated in the PT goats, and mild intolerance was noted in the HP goats. In 25 goats diagnosed with PT and having blood beta hydroxybutyric acid (BHBA) values ≥ 2.9 mmol/L, the correlation coefficient for BHBA with blood pH was non-significant.

  12. Influence of nitrogen source and pH value on undesired poly(γ-glutamic acid) formation of a protease producing Bacillus licheniformis strain.

    Science.gov (United States)

    Meissner, Lena; Kauffmann, Kira; Wengeler, Timo; Mitsunaga, Hitoshi; Fukusaki, Eiichiro; Büchs, Jochen

    2015-09-01

    Bacillus spp. are used for the production of industrial enzymes but are also known to be capable of producing biopolymers such as poly(γ-glutamic acid). Biopolymers increase the viscosity of the fermentation broth, thereby impairing mixing, gas/liquid mass and heat transfer in any bioreactor system. Undesired biopolymer formation has a significant impact on the fermentation and downstream processing performance. This study shows how undesirable poly(γ-glutamic acid) formation of an industrial protease producing Bacillus licheniformis strain was prevented by switching the nitrogen source from ammonium to nitrate. The viscosity was reduced from 32 to 2.5 mPa s. A constant or changing pH value did not influence the poly(γ-glutamic acid) production. Protease production was not affected: protease activities of 38 and 46 U mL(-1) were obtained for ammonium and nitrate, respectively. With the presented results, protease production with industrial Bacillus strains is now possible without the negative impact on fermentation and downstream processing by undesired poly(γ-glutamic acid) formation.

  13. 盐酸多西环素注射液最稳定pH值研究%A Study of the Stable pH Value of Doxycycline Hydrochloride Injection

    Institute of Scientific and Technical Information of China (English)

    胡海燕; 王亦琳; 黄耀凌; 徐倩; 徐士新; 朱馨乐; 朱明文

    2014-01-01

    The stable pH value of the veterinary doxycycline hydrochloride injection was predicted. The chemical stability of doxycycline hydrochloride injection was studied in the extensive pH range by classical isothermal kinetic method and single point kinetic method. The relationship between stability and pH value of the injection was investigated. The results showed that, the most stable pH value and stable pH range that predicted by the two methods were basically identical. The most stable pH value of doxycycline hydrochloride injection was 4.0. Single point kinetic method was simple and its workload was small compared with the classical kinetic method.%预测了兽用盐酸多西环素注射液稳定pH值。在广泛pH范围内,采用经典恒温法和单测点法对所研制的盐酸多西环素注射液进行化学稳定性研究,探讨pH值与稳定性之间的关系。结果表明,这两种方法预测的稳定 pH 值及稳定 pH 值范围基本一致,盐酸多西环素注射液最稳定pH值[( pH) m]为4.0,与经典法比较,单侧点法工作量小,简单易行。

  14. Illumina sequencing-based analyses of bacterial communities during short-chain fatty-acid production from food waste and sewage sludge fermentation at different pH values.

    Science.gov (United States)

    Cheng, Weixiao; Chen, Hong; Yan, ShuHai; Su, Jianqiang

    2014-09-01

    Short-chain fatty acids (SCFAs) can be produced by primary and waste activated sludge anaerobic fermentation. The yield and product spectrum distribution of SCFAs can be significantly affected by different initial pH values. However, most studies have focused on the physical and chemical aspects of SCFA production by waste activated sludge fermentation at different pH values. Information on the bacterial community structures during acidogenic fermentation is limited. In this study, comparisons of the bacterial communities during the co-substrate fermentation of food wastes and sewage sludge at different pH values were performed using the barcoded Illumina paired-end sequencing method. The results showed that different pH environments harbored a characteristic bacterial community, including sequences related to Lactobacillus, Prevotella, Mitsuokella, Treponema, Clostridium, and Ureibacillus. The most abundant bacterial operational taxonomic units in the different pH environments were those related to carbohydrate-degrading bacteria, which are associated with constituents of co-substrate fermentation. Further analyses showed that during organic matter fermentation, a core microbiota composed of Firmicutes, Proteobacteria, and Bacteroidetes existed. Comparison analyses revealed that the bacterial community during fermentation was significantly affected by the pH, and that the diverse product distribution was related to the shift in bacterial communities.

  15. What Do I Want to Be with My PhD? The Roles of Personal Values and Structural Dynamics in Shaping the Career Interests of Recent Biomedical Science PhD Graduates

    Science.gov (United States)

    Gibbs, Kenneth D., Jr.; Griffin, Kimberly A.

    2013-01-01

    Interest in faculty careers decreases as graduate training progresses; however, the process underlying career-interest formation remains poorly defined. To better understand this process and whether/how it differs across social identity (i.e., race/ethnicity, gender), we conducted focus groups with 38 biomedical scientists who received PhDs…

  16. What Do I Want to Be with My PhD? The Roles of Personal Values and Structural Dynamics in Shaping the Career Interests of Recent Biomedical Science PhD Graduates

    Science.gov (United States)

    Gibbs, Kenneth D., Jr.; Griffin, Kimberly A.

    2013-01-01

    Interest in faculty careers decreases as graduate training progresses; however, the process underlying career-interest formation remains poorly defined. To better understand this process and whether/how it differs across social identity (i.e., race/ethnicity, gender), we conducted focus groups with 38 biomedical scientists who received PhDs…

  17. Advances in the effects of pH value of micro-environment on wound healing%微环境pH值对创面愈合的作用研究进展

    Institute of Scientific and Technical Information of China (English)

    田瑞瑞; 李娜; 魏力

    2016-01-01

    Wound healing is a complex regeneration process,which is affected by lots of endogenous and exogenous factors.Researches have confirmed that acid environment could prevent wound infection and accelerate wound healing by inhibiting bacteria proliferation,promoting oxygen release,affecting keratinocyte proliferation and migration,etc.In this article,we review the literature to identify the potential relationship between the pH value of wound micro-environment and the progress of wound healing,and summarize the clinical application of variation of pH value of micro-environment in wound healing,thereby to provide new treatment strategy for wound healing.

  18. Prediction of Optimum pH of G/11 Xylanases and the Relationship between the Location of Amino Acid and Optimum pH Value%G/11木聚糖酶最适 pH 值的预测及其与氨基酸位置的关系

    Institute of Scientific and Technical Information of China (English)

    林源清; 张光亚

    2014-01-01

    把木聚糖酶全序列均分为 N 端,中间端(I 端)及 C 端3个部分,并分别以全序列及分段氨基酸的组成作为模型输入值.通过主成分分析(PCA)方法探讨全序列及分段氨基酸组成和最适 pH 值的相关性,运用均匀设计法分别优化支持向量机和 BP 神经网络运行参数.研究结果表明:支持向量机获得的预测模型优于神经网络,其中 RBF 支持向量机是最佳的模型.主成分分析结果显示:I 端主成分跟最适 pH 值相关性最高;相关系数 R 绝对值为0.68,得到的结果与支持向量机结果一致.%We divided the xylanase sequences into three equally segments named N-terminus,I-terminus and C-terminus. And then,we calculated the amino acid compositions of the whole sequences and the segmented sequences,respectively. The amino acid compositions were used as the input values of these models.The principal component analysis (PCA) method was utilized to analyze the relationship between the amino acid composition and the optimum pH.The uniform de-sign was used to optimize the running parameters of support vector machines (SVM)and neural network (BPNN),re-spectively.Our results showed the predicted model obtained by SVM was better than that of BPNN,and the SVM model based on RBF kernel was best.The results of PCA showed the correlation between principle component and optimum pH was best in the I-terminus with the R=-0.68,which coincided with the result of the SVM.

  19. Effect of Cu and Ni on Growth,Mineral Uptake,Photosynthesis and Enzyme Activities of Chlorella vulgaris at different pH Values

    Institute of Scientific and Technical Information of China (English)

    P.K.RAI; NirupamaMALLICK; 等

    1994-01-01

    A pH dependent reduction in growth,pigment,ATP content,O2 evolution,carbon fixation,photosynthetic electron transport system,nutrient uptake(No3- and NH4+) nitrate reductase,and ATPase activities and increase in K+-efflux of Chlorella vulgaris was noticed following supplementation of Cu and Ni to the culture medium.PSⅡ was found to be more sensitive to both pH and metals than PS I.Though.nitrate reductase(NR)was more sensitive to both pH and metals,the ATP ase was however,more sensitive to metals but less sensitive to acidic pH.Acid pH was found to inhibit the nutrinent(NO3-and NH4+) uptake and nitrate reductase in a non-competitive manner.The inhibition produced by the test metals alone was of non-competitive type for NO3- uptake,nitrate reductase and ATPase and competitive for NH4+ uptake.Acidity not only inhibited the metabolic variables directly but also through facilitated uptake of metals and increased membrane permeability.A very low sensitivity of ATPase to acidic pH seems to be responsible for the survival of algae in acid environment.

  20. Research on Step-wise Control pH Value in the First-step Fermentation Process of Vitamin C%维生素C一步发酵过程阶梯式控制pH值的研究

    Institute of Scientific and Technical Information of China (English)

    付海晨; 齐代鹏

    2011-01-01

    Currently change of the pH value was mainly adjusted by calcium carbonate during the first-step fermentation process of Vitamin C(referred to as VC).Through adding sodium carbonate,to step-wise control the pH value of the VC fermentation process.The results showed that pre-fermentation was controled the pH value at 6.0,post-fermentation pH value at 5.0 by adding the sodium carbonate,the fermentation period could be shortened further 33%.%目前维生素C(简称VC)第一步发酵过程中pH值的变化主要由CaCO3来调解。研究了Na2CO3代替CaCO3,并采用阶梯式控制发酵过程的pH值。结果表明:通过Na2CO3来控制发酵过程中pH值[前期控制pH值为6.0(8 h前),后期控制pH值为5.0],可以缩短一步发酵周期33%。

  1. Influence of pH Value of Emulsified Asphalt on CA Mortar Work Performance%乳化沥青pH值对CA砂浆工作性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘宝举; 宁少英; 杨元霞; 陈欢

    2012-01-01

    基于乳化沥青pH值对ξ电位的影响,研究了乳化沥青pH值对CA砂浆流动度、可工作时间、分离度、含气量、表观密度及浆体体系pH值的影响.结果表明:乳化沥青pH值在2.5~9.5时,CA砂浆流动度处于稳定状态;pH<2.5,pH>9.5时,CA砂浆流动度均增加,且后者增加显著;pH=11.5时,其流动度达到最高;pH=9.5时,60 min后CA砂浆流动度经时损失最大,达到26.09%.pH=2.5时,CA砂浆表观密度随时间的延长逐渐减小;pH=9.5时,CA砂浆表观密度随时间的延长而增大.pH=1.5,9.5时,CA砂浆的分离度最小.乳化沥青pH值对CA砂浆浆体体系pH值的影响不大.为提高CA砂浆的综合性能,乳化沥青的合适pH值为1.5或9.5.%Influence of pH value of emulsified asphalt on work performance of CA mortar was studied by measuring the effect of pH on zeta potential. Results show that the pH of emulsified asphalt has great influence on the fluidity, working time, separating degree, air content and apparent density and pH of CA mortar, which results in the influence of pH of emulsified asphalt on zeta potential. When pH = 2. 5 -9. 5, the fluidity of CA mortar keeps in a stable level, while pH<2. 5, the fluidity increases, and it increases significantly when pH>9. 5, the fluidity reaches a maximum value when pH = ll. 5. The loss of fluidity with time reaches to 26. 09% when pH = 9. 5. The apparent density decreases with time when pH =2. 5, and it increases when pH = 9. 5. Separating degree has no effect on the symbols of the ζ potential, but it has influence on its absolute value. The bigger the absolute value, the smaller the separating degree and vice versa. When pH = l. 5 and 9. 5, the separating degree was small. pH of asphalt has a little influence on the pH of CA mortar. The appropriate pH of asphalt for CA mortar is 1. 5 or 9. 5.

  2. Effect of pH Value on the Desulfurization Process in Flue Gas Desulfurization%烟气脱硫中pH值对脱硫过程的影响

    Institute of Scientific and Technical Information of China (English)

    王振华

    2014-01-01

    Wet Limestone - gypsum flue gas desulfurization system (FGD system) is currently dominant in the domestic coal-fired power plant FGD system. FGD is designed to chemically remove sulfur dioxide in the flue gas leaving the flue gas will be purified. pH value as a measure of gypsum slurry pH, is an important technical parameters of the desulfurization process, at the same time as an environmental indicators relate with chemical reaction. Utilization of limestone, desulfurization efficiency and quality of gypsum slurry are closely related with the control of pH value. We usually control the pH value by controlling the mixing amount of limestone (CaCO3). Increasing the pH value can increase the amount of limestone, and vice versa reduction. On operation, the stability of pH value must be maintained. Increasing the pH value will increase the alkalinity of system and desulfurization efficiency, but the utilization of limestone will be reduced, and accelerate the formation of scale, ultimately affect the quality of gypsum. Reducing the pH value will increase the acidity of the system, improve the utilization of limestone, accelerate precipitation of gypsum crystals, but it will also accelerate the corrosion of the system, make the system is unstable, and the desulfurization efficiency will be greatly reduced. Therefore, the control of slurry pH value should seek the best value to meet the requirements under the premise of the desulfurization rate and generally the pH is controlled in the best range of 5.0-5.8.%湿法石灰石-石膏烟气脱硫系统(即FGD系统)目前在国内外燃煤电站FGD系统中占绝对优势。FGD的目的是用化学方法除去烟气中的二氧化硫而使烟气得以净化。pH值作为石膏浆液酸碱度的度量,是脱硫工序中一项重要的技术参数,同时可作为一项与化学反应相关的环境指标。石灰石利用率、脱硫效率和石膏浆液品质等与pH值的控制密切相关。通常我们

  3. Experimental simulation on migration and conversion of organophosphor by pH value in aquitard%pH值对有机磷在弱透水层中迁移转化的试验模拟

    Institute of Scientific and Technical Information of China (English)

    宋顶峰; 李红艳; 李建萍; 李绪谦; 罗艳春

    2011-01-01

    In order to study the effect of pH value on migration and conversion to organophosphor in permeable clay, permeation and pressure equipment were adopted to simulate the migration and conversion process of organophosphor permeating the aquitard in the polluted aquifer. It indicates that the migratory capacity of organophosphor in aquitard is weak, while the mineralization rate of organophosphor is between 93.5% and 99. 95% with different pH conditions. During pH value as 5.5 to 8. 5, the activity of acid phosphatase going up with pH value increases, while the ability of degradation and conversion becomes stronger, and the retardation for organophosphor in clay enhances along with pH value. When pH value is 5.5, the migration rate is 6. 5%. As the pH value reaches to 8. 5, the mineralization rate increases obviously with the migration rate less than 0. 05%, which hard for organophosphor permeate into the deep phreatic water and bring pollution.%为研究渗透水PH值对有机磷通过弱透水黏土层迁移转化的影响规律,采用黏性土层充压渗透装置模拟污染潜水中有机磷渗透通过弱透水层的迁移转化过程.研究发现,有机磷组分通过弱透水层的迁移能力总体较弱,不同PH值条件下有机磷的矿化率为93.5%~99.95%;在进水PH值为5.5~8.5时,进水PH值越高,土层中磷酸酶的活性也越高,降解转化有机磷的能力也越强;黏土对有机磷的阻滞能力也增强.进水PH值为5.5时,迁移率为6.5%;当PH达到8.5时,矿化率明显增加,迁移率<0.05%,使其不易渗入深层地下水引起污染.

  4. Clinical Psychology Ph.D. Program Admissions: Differential Values as a Function of Program Characteristics and the Implications of the Mentor-Model Approach

    Science.gov (United States)

    Metzger, Jesse A.

    2010-01-01

    The aims of this research were to 1) examine the qualities for which applicants are selected for entrance into clinical psychology Ph.D. programs, and 2) investigate the prevalence and impact of the mentor-model approach to admissions on multiple domains of programs and the field at large. Fifty Directors of Clinical Training (DCTs) provided data…

  5. Clinical Psychology Ph.D. Program Admissions: Differential Values as a Function of Program Characteristics and the Implications of the Mentor-Model Approach

    Science.gov (United States)

    Metzger, Jesse A.

    2010-01-01

    The aims of this research were to 1) examine the qualities for which applicants are selected for entrance into clinical psychology Ph.D. programs, and 2) investigate the prevalence and impact of the mentor-model approach to admissions on multiple domains of programs and the field at large. Fifty Directors of Clinical Training (DCTs) provided data…

  6. Birth asphyxia measured by the pH value of the umbilical cord blood may predict an increased risk of attention deficit hyperactivity disorder

    DEFF Research Database (Denmark)

    Mikkelsen, Susanne Hvolgaard; Olsen, Jørn; Bech, Bodil Hammer

    2017-01-01

    AIM: Although birth asphyxia is a major risk factor for neonatal and childhood morbidity and mortality, it has not been investigated much in relation to attention deficit hyperactivity disorder (ADHD). We examined whether birth asphyxia measured by the pH of the blood in the umbilical artery cord...

  7. pH值对羟丙基胍胶压裂液性能的影响%Effect of pH Value on Performance of Hydroxypropyl Guar Gum Fracturing Fluid

    Institute of Scientific and Technical Information of China (English)

    唐洪彪; 王世彬; 郭建春

    2016-01-01

    为了弄清压裂液的pH值在水力压裂施工不同阶段所起的作用,开展了pH值对羟丙基胍胶溶胀、交联、携砂、破胶性能的影响研究。结果表明,pH=7数10时,羟丙基胍胶在20 min内完全溶胀;pH=11数14时,羟丙基胍胶至少需要50 min才能完成溶胀。Ostwald-Dewaele方程能描述冻胶黏度随剪切速率变化关系,pH=7数12时的稠度系数较大,大于16744 mPa·sn;pH=13数14时的稠度系数明显减小,小于3130 mPa·sn。静态沉降实验表明,pH=9数12时的静态沉降速度较小,为1.31数5.94 mm/h;pH=7、8、13时的静态沉降速度较大,大于10.64 mm/h;pH=14时,支撑剂20 s内完成沉降。破胶实验研究发现,冻胶在pH=7数10时的破胶速度大于pH=1数14时的破胶速度;pH=7数12时,残渣含量较小,为400 mg/L左右。满足各施工阶段的pH值范围为9数10。图5表2参12 lnha=lnK+(n-1)lng%pH was an important factor affecting the performance of hydraulic fracturing. The effect of pH on the swelling performance of hydroxypropyl guar gum,crosslinking properties,proppant settlement,guar gum degradation was studied. The results showed that,at the pH value of 7—10,the swelling time of hydroxypropyl guar gum was less than 20 min,while at the pH value of 11—14 ,the swelling time was larger than 50 min ,the swelling rate at the pH value of 7—10 was relatively higher than that at the pH value of 11 —14. The relationship between gel viscosity and shear rate could be described by the Ostwald-Dewaele equation ,and at the pH value of 7—12 ,the consistency coefficient of hydroxypropyl guar gum solution was larger than 16744 mPa·sn,while the consistency coefficient at the pH value of pH 13—14 was less than 3130 mPa·sn. The proppant settlement experiments showed that,at the pH value of 9—12,the settling rate of proppant was relatively low,being of 1.31—5.94 mm/h;at the pH value of 7,8,13,the settling rate increased and the value

  8. Relationship of Gastric pH Value and Feeding Intolerance in Very Low Birth Weight Infants (VLB-WI)%极低出生体重儿胃液 pH 值与喂养不耐受的相关性研究

    Institute of Scientific and Technical Information of China (English)

    郝群英

    2016-01-01

    Objective]To explore the relationship of gastric pH value and feeding intolerance in very low birth weight infant (VLBWI).[Method]80 cases of very low birth weight children in our hospital from January 2010 to December 2014 also in the neonatal intensive care unit were chosen for our study.Using the feeding intolerance di-agnostic criteria,the children were selected and divided into two groups.Group 1 had no feeding intolerance (36 cases)and Group 2 had feeding in tolerance (44 cases).The two groups of children were observed in respect to gastric pH value,feeding conditions (feeding time,the amount of intake and gastric residue),and feeding toler-ance (bloating times,frequency of vomiting,abnormal stool frequency).[Results]Group 1 had a feeding intoler-ance rate of 100%,significantly higher than the 8.33% rate in Group 2 (P <0.05),while the average gastric pH value was also higher in Group 1 than Group 2 (P <0.05).The occurrence of VLBWI feeding intolerance and gas-tric pH value were positively correlated r =0.77,P =0.00.[Conclusion]Gastric pH value in very low weight new-borns with feeding intolerance showed significant correlation with the gastric pH levels in the infants.It is worthy of effective monitoring to help clinicians and nurses to understand neonatal gastrointestinal function and promote neonatal rehabilitation reference.%【目的】探讨极低出生体重儿(VLBWI)胃液 pH 值与喂养不耐受的关系。【方法】选取2010年1月至2014年12月本院新生儿重症监护室(NICU)收治的 VLBWI 80例。参照喂养不耐受诊断标准,将入选患儿分为喂养耐受组36例,喂养不耐受组44例。比较两组患儿的胃液 pH 值、喂养耐受情况(胃残留量、腹胀、呕吐、大便异常)。【结果】喂养不耐受组喂养不耐受发生率为100%,高于喂养耐受组的8.33%(P <0.05),同时其平均胃液 pH 值高于喂养不耐受组(P <0.05);VLBWI 胃液 pH 值与胃残留量呈正相关,r =0.77,P =0.00

  9. 右旋糖酐40葡萄糖注射液 pH 值与5-羟甲基糠醛、糠醛含量的相关性分析%Correlation Analysis of Furfural, 5-hydroxymethylfurfural Content and pH Value of Dextran 40 and Glucose Injection

    Institute of Scientific and Technical Information of China (English)

    郭欢迎; 耿庆光; 王嫦鹤

    2015-01-01

    Objective To analyze the correlation of furfural, 5-hydroxymethylfurfural (5-HMF) content and pH value of dextran 40 and glucose injection, and to provide reasonable suggestions for the production, transportation and use. Methods High performance liquid chromatography method was used to determine the content of 5- HMF and furfural of 90 batches of dextran 40 and glucose Injection. The pH value of the solution was determined by acidometer. Correlation of furfural, 5-HMF content and pH value was analyzed by SPASS 17.0. The destructive tests were carried out to verify the conclusion. Results There is a negative correlation between the value of pH and content of 5- HMF, and the content of furfural was positively correlated with 5- HMF. Destructive test results show that, the decrease of pH value will lead to the generation of 5- HMF and furfural. Conclusion Through the strict control of pH value, the stability of dextran 40 and glucose injection can be increased. And the increase 5- HMF and furfural content of the preparation could be suppressed too.%目的:对右旋糖酐40葡萄糖注射液的 pH 值与5-羟甲基糠醛、糠醛含量进行相关性分析,为其生产、运输和使用提供合理化建议。方法采用高效液相色谱法对所有90批右旋糖酐40葡萄糖注射液中的5-羟甲基糠醛、糠醛进行测定,同时采用酸度计测定溶液的 pH 值,并用 SPASS 17.0对测定结果的 pH 值与5-羟甲基糠醛、糠醛进行相关性分析,并采用破坏性试验对结论进行验证。结果右旋糖酐40葡萄糖注射液的 pH 值与5-羟甲基糠醛的含量负相关,5-羟甲基糠醛的含量与糠醛的含量呈正相关。破坏性试验结果证明,pH 值的降低会导致5-羟甲基糠醛和糠醛的生成。结论通过严格控制该制剂的 pH 值,可以增加右旋糖酐40葡萄糖注射液的稳定性,抑制制剂中5-羟甲基糠醛和糠醛含量的增加。

  10. Effect of pH value on adiabatic decomposition characteristics of hydrogen peroxide%pH值对双氧水绝热分解特性的影响

    Institute of Scientific and Technical Information of China (English)

    孙峰; 谢传欣; 张帆; 金满平; 王振刚

    2012-01-01

    In order to study the influence of pH value on the thermal hazard of hydrogen peroxide, VSP2 (Vent Size Package 2) was used to analyze the thermal behavior of hydrogen peroxide (mass fraction 27. 5%) with different pH values of 1.8, 4, 5,6,7,8 under adiabatic condition. The adiabatic decomposition characteristics of the hydrogen peroxide with different pH values were recorded. The thermal decomposition kinetics of the decomposition reaction concerned was obtained. The time to the maximum reaction rate at 30 ℃ under adiabatic condition was also worked out from the kinetics data. The results show that as the pH value of hydrogen peroxide increasing, the onset exothermic temperature decreases, and the time to the maximum reaction rate under adiabatic conditions gets shorter, so the risk probability of thermal runaway significantly increases. When hydrogen peroxide is stored in the industrial conditions, there is a certain risk when pH value is 6, and thermal runaway is almost inevitable when pH value is more than 7.%为了考察pH值对双氧水热危害的影响,利用VSP2绝热量热仪对pH值分别为1.8,4,5,6,7及8的质量分数为27.5%的双氧水进行了绝热条件下测试,得到了不同pH值双氧水的绝热分解特征,求得了双氧水的分解动力学,并计算得到双氧水在起始温度为30℃时绝热条件下到达最大反应速率所需时间.结果表明:当双氧水pH值增加时,起始放热温度降低,到达最大反应速率所需时间缩短,热失控危险性明显增加,双氧水在工业条件下存储时,当pH值增加至6时就有一定危险性,当pH值增加至7以上时热失控几乎不可避免.

  11. 近30年川中丘陵县域表层土壤 pH 值时空变化分析--以四川仁寿县为例%Temporal and Spatial Variation of Topsoil pH Value in Hilly Area of Middle Sichuan Basin during 1981-2012:A Case Study in Renshou County,Sichuan

    Institute of Scientific and Technical Information of China (English)

    李珊; 肖怡; 李启权; 张维; 罗由林; 蒋欣烨; 张浩

    2015-01-01

    【目的】研究1981~2012年仁寿县表层土壤 pH 值时空变化特征。【方法】以1980年第二次土壤普查资料和2010年实地采样数据为基础,应用 GIS 技术和地统计学等研究方法分析研究区表层土壤 pH 值的时空变化及其在不同土壤类型、成土母质和土地利用方式下的变化特征。【结果】1981~2012年间研究区表层土壤 pH 值的空间分布格局基本一致,以东北和西南高,西北和东南低。土壤 pH 值由7.10下降到6.80,整体表现出酸化趋势,酸化程度由中部向西北和东南增强。其中以灌口组泥砂岩、自流井组泥灰岩、第四系老冲积冰水沉积物及须家河组砂岩发育形成的土壤 pH 值下降幅度最大,在9.69%~12.65%之间;各土壤类型 pH 的下降幅度与其初始值呈负相关,表现为黄壤(12.30%)>水稻土(4.46%)>紫色土(2.95%);不同土地利用方式土壤 pH 的下降幅度以园地和水旱轮作最大,分别下降了0.50和0.66个单位。半方差分析表明,土壤 pH 值的变程由65.9 km 缩短至52.7 km,块金值与基台值的比值由29.1%增加到30.1%,随机性因素使结构性因素的作用减弱,空间自相关程度和范围降低。影响因素的显著性分析表明,成土母质和土壤类型对1981年和2012年土壤 pH 值均有极显著影响(P <0.01),土地利用方式的作用由显著(P <0.05)变为极显著(P <0.01)。【结论】近30年来研究区土壤呈酸化趋势,表层土壤 pH值时空变异受成土母质和土壤类型等结构性因素及土地利用方式等随机性因素的影响,且随机性因素对研究区表层土壤 pH 值时空变异的影响在增强。%Objective]The aim of this paper was to reveal the temporal and spatial variation of topsoil pH value in Renshou county of Sichuan during 1981 -2012.[Method]Based on the data of the second national

  12. Characterization of Cu ( Ⅱ ) Binding with Rabbit Liver Metallothionein under Various pH Values Conditions%不同pH值条件下兔肝金属硫蛋白与铜(Ⅱ)结合的研究

    Institute of Scientific and Technical Information of China (English)

    粱淑轩; 艾丹丹; 孙汉文

    2011-01-01

    目的 研究不同pH值条件下兔肝金属硫蛋白(MT)与铜(Ⅱ)结合情况.方法 向2ml(pH值为3,4,5,6,7)的兔肝锌-金属硫蛋白溶液加入9.2×10-4 mol/L硫酸铜溶液0.2 ml.在200~300 nm波长下测定相应pH值Zn-MT溶液及其加入硫酸铜后与铜(Ⅱ)结合的紫外吸收情况.采用半透膜透析的方法除去过量金属离子,并采用电感耦合等离子体质谱( ICP-MS)法测定金属硫蛋白与铜(Ⅱ)的结合量.结果在相同的实验条件下,与金属硫蛋白结合的铜(H)含量随着pH值的升高而增加.透析24 h后,与金属硫蛋白结合的铜(Ⅱ)含量随着pH值升高呈现先下降后升高的趋势;且当pH=5时,与金属硫蛋白结合的铜(Ⅱ)含量最低.结论 在pH=5时,金属硫蛋白释放质子,不利于铜与金属硫蛋白的结合,铜与金属硫蛋白的结合能力较弱.由于组成金属硫蛋白的α-、β-结构域的差异,不同pH值时锌和铜与金属硫蛋白的结合位点不同,使得其与金属的结合能力存在差异.在pH值为3,4时,锌从金属硫蛋白中脱落,铜的结合量增加.%Objective To study the impact of pH value on the binding of Cu (Ⅱ) with rabbit liver metallothionein(MT). Methods 0.2 ml 9.2×10-4 mol/L CuSO4 solution was added to 2 ml of rabbit liver zinc-metallothionein solution at pH values of 3,4,5,6 and 7 respectively. UV absorption spectrogram of Zn-MT solution and Cu( Ⅱ) binding Zn-MT solution were scaned at 200-300 nm. Copper ( Ⅱ) binding with metallothionein was determined by inductively coupled plasma mass spectrometry (ICP-MS) method after removing the excess Cu2+ by semi-permeable membrane. Results The levels of copper( Ⅱ) binding with metallothionein increased with pH value increasing. Metallothionein binding copper (Ⅱ) content with the pH value declined at first, then increased, and copper (Ⅱ) content reached the lowest value at pH value of 5. Conclusion It is not conducive to copper binding metallothionein and the ability of

  13. Incidence of spontaneous bacterial peritonitis in patients with ascites. Diagnostic value of white blood cell count and pH measurement in ascitic fluid

    DEFF Research Database (Denmark)

    Storgaard, J S; Svendsen, Jesper Hastrup; Hegnhøj, J

    1991-01-01

    During a 21-month period, 65 consecutive patients admitted with ascites were included in a prospective study of the incidence of spontaneous bacterial peritonitis, and paracentesis was performed on admission. The ascitic fluid was cultured, ascitic leucocytes were counted and pH was measured....... Bacterial growth was found in five patients with chronic liver disease, who were diagnosed as having spontaneous bacterial peritonitis (SBP), since no intra-abdominal focus could be demonstrated. Thus, the incidence of SBP in this material was 7.7% (95% confidence limits: 2.5-17%). SBP was caused...

  14. Effects of pH value of reaction solution on structure and electrochemical performance of calcium-containing active material of secondary zinc electrodes

    Institute of Scientific and Technical Information of China (English)

    陈华; 王建明; 郑奕; 张鉴清; 曹楚南

    2004-01-01

    The calcium-containing active material of secondary alkaline zinc electrodes was prepared by a chemical coprecipitation method and characterized by scanning electron microscopy(SEM) and X-ray diffractometry(XRD).Their electrochemical performance was tested by the Galvanstatic charge-discharge method. The experimental results show that the sample synthesized at pH = 11.15 has a typical calcium zincate crystal. The zinc electrode using this sample as active material shows higher discharge capacity, more negative discharge plateau potential and longer cycle lifetime.

  15. Effects of applying different pH values on mung bean seed germination and seedlings growth%pH值对绿豆种子萌发和幼苗生长的影响

    Institute of Scientific and Technical Information of China (English)

    于秋良; 杨志贤; 李忠芳; 卢伟琳; 何子龙; 岑美婷; 覃娟清; 梁丽清; 李稳

    2012-01-01

    This research investigated the effects of applying different pH values and determining the pH soaking time on mung bean seed germination and seedlings growth in order to provide basis for reducing soil acidity stress by scientifically raising seedlings in Southern China bean planting aren. [Method ]The experiment was designed with 5 different degrees of pH values and 2 soaking times. The seed germination and seedling growth of mung bean were observed. [ResultjThe results showed that the germination speed was the fastest out of all treatments when the pH level was 7.5; under this pH level, the most numerous seedling germination was also observed. Two days after the seeds were soaked in pH 7.5 solutions for 6 and 12 hrs, the germination rate was 87.5% and 92.5%, respectively. On the other hand, four days after seeding, the tallest seedling plant height were measured after the seeds were soaked for 6 and 12 hrs under the pH solution of 7.5 and 7.0, respectively. For all seeds soaked for 6 and 12 hrs under pH level 6.5 and pH level 7.0, respectively, their seedlings showed the highest fresh weight, while those soaked in pH level 8.0 showed the heaviest dry seedling weight. [Conclusion]The optimal pH value for soaking mung bean seeds should be between 7.0-7.5 to achieve the best mung bean germination and seedling growth in Hezhou districts of Cuangxi.%[目的]研究不同pH值溶液及其不同浸泡时间对绿豆种子萌发和幼苗生长的影响,为在南方地区通过科学育苗减少土壤酸胁迫提供科学依据.[方法]用pH值6.0~8.0溶液分别浸泡绿豆种子6、12 h,观察绿豆种子萌芽及幼苗生长状况.[结果]当溶液pH值为7.5时,绿豆种子萌发速度最快、数量最多,2d后浸种6、12h的发芽率分别为87.5%和92.5%;浸种6、12h,播种4d后分别以pH值7.5和7.0处理的幼苗株高最高.浸种6、12h时,分别以pH值6.5、7.0处理的绿豆幼苗鲜重最高,而均以pH 8.0处理的幼苗干重最高.[结论]在广

  16. Influence of different acids for adjusting the dyebath ph value on the dyeability of polyester knitwear dyed with disperse yellow 23

    Directory of Open Access Journals (Sweden)

    Miljković Milena N.

    2011-01-01

    Full Text Available In this paper the influence of the formic and oxalic acids, as substances for dyebath pH adjusting, on the dyeability of polyester fabric dyed with disperse dye Disperse Yellow 23 was examined. The polyester undyed knitwear samples were dyed in baths containing the acids under the same dyeing conditions. Color differences of the samples were assessed using the reflectiometry technique and expressed in terms of CIELcoordinates. The influence of the tested acids on the surface structure of dyed polyester fibers was examined using the scanning electron microscopy (SEM. It was found that the differences in obtained dyeabilities, in the presence of both formic and oxalic acid, are acceptable according to both M&S 83A and CMC (2:1 standards which was not the case with acetic acid. Therefore, acetic acid can be replaced with either formic or oxalic acid as substances for dyebath pH adjusting in the dyeing process described in this paper. SEM micrographs showed small differences in the surface structure of dyed fibers, as well as differences in the shape of undyed samples’ reflectance curves in presence of the acids. Since all of the color differences were quite small, it can be concluded that the influence of formic and oxalic acids on the polyester knitwear dyeability is not significantly different than that of acetic acid.

  17. 天山东部冰芯pH值和电导率的大气环境空间差异%The pH value and electrical conductivity of atmospheric environment from ice cores in the Tianshan Mountains

    Institute of Scientific and Technical Information of China (English)

    董志文; 张明军; 李忠勤; 王飞腾; 王文彬

    2009-01-01

    Electrical Conductivity Measurement (ECM) from ice core is a representative index for atmospheric environmental change. The pH value and ECM from three shallow ice cores (each 3.85 m, 231 ice samples total) on Glacier No.1 at the headwater of Urumqi River, Gla-cier No.48 in Kuitun area, and Miaoergou Glacier in Hami area in the eastern Tianshan Mountains, western China, were measured and analyzed for atmospheric environment re-cords research. Ice core record shows that the changing trend of pH and ECM in three sites in recent years is different: ECM in Kuitun increases with the ice depth change, but ECM in Hami and Urumqi Glacier No.1 ice cores show a decreasing trend. Average ECM value in Hami is much larger than other two sites, just as the dust concentration and ions concentra-tion are also very high in this site. ECM records in all three sites are mainly affected by aerosol mineral dust of Central Asia, and correlative coefficients of ECM and mineral ions such as Ca2+, Mg2+, Na+ are all significantly high. The pH value and ECM are also significantly high correlative coefficients in the eastern Tianshan Mountains. Comparison between the eastern Tianshan Mountains and other sites in western China, and Polar Regions, shows that the difference of ECM can very well reflect the spatial difference of worldwide atmospheric environment.

  18. 糖厂澄清工段pH值测量电路设计与实现%Design and implementation of pH value measurement circuit in clarification workshop section in sugar industry

    Institute of Scientific and Technical Information of China (English)

    宋春宁; 宋云鹏; 林小峰; 宋绍剑; 李荣军

    2012-01-01

    Aiming at the impedance matching and electromagnetic interference problems in pH value measuring in the complex conditions in sugar factory,for the first time,HCNR201 optocoupler isolation is applied to INA116 preamplification circuit, the pH value measuring circuit is worked out. The experimental result shows that this circuit can not only solve the impedance matching and electromagnetic interference problems,but also collect the pH value quickly and precisely.%针对糖厂复杂工作环境中pH玻璃电极测量存在的阻抗匹配和工业现场电磁信号干扰问题,率先把线性光耦HCNR201运用到INA116前置放大电路中,设计出pH值测量电路.实验结果表明:该电路可以解决阻抗匹配和电磁干扰2个问题,并能快速准确采集蔗汁pH值.

  19. Influence of pH Value on the Determination of Hexavalent Chromium by Diphenylcarbazide Spectrophotometry%pH值对二苯碳酰二肼分光光度法测定六价铬的影响

    Institute of Scientific and Technical Information of China (English)

    王海云; 李敏锐; 廖涛; 谭飞帆; 邓杰

    2012-01-01

    Based on the 1,5 -diphenylcarbazide spectrophotometry, we researched on the influence of pH value on the determination of hexavalent chromium. By adding different amounts of acid into two water samples with different volumes and concentrations, we measured the absorbances of the solutions so as to determine the hexavalent chromium. Through analysis by EXCEL on the measured data, we found that the absorbance reduced with the decrease of pH value. In the presence of high acidity, which means small pH value, the measured hexavalent chromium was smaller than the original value before adding acid. Therefore, the variation of pH value had an impact on the measurement of hexavalent chromium. Moreover, we employed the gray system model GM( 1,1) to process the experimental data, and derived a linear equation for the absorbance under different acidities. Through t test and F test, no significant difference was found between calculated absorbance and measured absorbance. This research is helpful to quantitatively looking into the influence of pH value on hexavalent chromium determination.%为获得不同pH值对测定六价铬(Cr(Ⅵ))的影响,以标准分析方法二苯碳酰二肼(C13H14N4O)分光光度法为基础,选用2种体积浓度的水样,分别加入不同的酸量,测定吸光度.经EXCEL软件对实测数据分析,得出加酸量与吸光度具有紧密的相关性,发现吸光度随着溶液pH值的减小而减小,酸度偏大,测定的实际结果比真实值小,pH值的不同对Cr(Ⅵ)测定结果具有影响.采用灰色系统模型GM(1,1)对实验数据进行处理,推导出不同酸度下的吸光度直线方程式.经t检验和F检验证明,计算出的吸光度值与测定值不存在显著性差异,可帮助定量掌握不同酸度条件下对测定Cr(Ⅵ)产生影响具有一定的作用.

  20. Effect of pH value on VFA concentration and composition during anaerobic fermentation of kitchen waste%pH值对餐厨垃圾厌氧发酵产挥发性脂肪酸的影响

    Institute of Scientific and Technical Information of China (English)

    张玉静; 蒋建国; 王佳明

    2013-01-01

    Under mesophilic conditions(35 °C), batch experiments were carried out to determine the effect of pH value on volatile fatty acid(VFA) concentration and composition during anaerobic acidogenesis of kitchen wastes. The pH value was uncontrolled in one reactor and controlled at 5.0,6.0,7.0 in other reactors. The results showed that the greatest degree of hydrolysis and acidogenesis was obtained and more organic acid was produced when the pH value was controlled at 6.0. When the pH value was controlled at 6.0, the maximum VFA concentration and yields of 40.89g/L and 0.328gVFA/gVS was obtained in the 68th hour, and was 8 times of that when the pH value was not controlled. The product composition in the acid reactor strongly depended on the pH value. The pH value of the uncontrolled reactor dropped from 6.6 to 3.8 quickly within 24 hours. Ethanol was the main product, accounted for 59.8% of total end products. So the typical ethanol-type fermentation occurred when the pH value was not controlled. It was butyric acid-type fermentation when the pH value was controlled at 5.0, 6.0 and 7.0. Acetic acid was main product at pH 5.0, butyric acid was dominant at pH 6.0, proportion of acetic acid and butyric acid was similar to each other at pH 7.0. The optimum pH value of hydrolysis and acidogenesis of kitchen wastes was 6.0.%通过间歇实验研究了中温条件下pH值对餐厨垃圾厌氧发酵产挥发性脂肪酸(VFA)的影响.考察了pH值为5.0、6.0、7.0及不控制pH值下的有机酸浓度及组成情况.结果表明,当控制反应器中pH值为6.0时,餐厨垃圾水解酸化效果最好,比其他pH值条件下产生更多的有机酸.pH值为6.0时,VFA浓度与单位VS产酸量在第68h达到最大值分别为40.89g/L和0.328gVFA/gVS,是不控制pH值时的8倍.pH值对发酵产物组成影响显著.不控制pH值时,反应器内的pH值在241h内由6.6迅速下降到3.8,乙醇为主要的发酵产物,占59.8%,表现为典型的乙醇型

  1. Biosorption of U(VI) by the green algae Chlorella vulgaris in dependence of pH value and cell activity

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, M., E-mail: M.Vogel@fzd.de; Guenther, A.; Rossberg, A.; Li, B.; Bernhard, G.; Raff, J.

    2010-12-15

    Biosorption of uranium(VI) by the green alga Chlorella vulgaris was studied at varying uranium concentrations from 5 {mu}M to 1 mM, and in the environmentally relevant pH range of 4.4 to 7.0. Living cells bind in a 0.1 mM uranium solution at pH 4.4 within 5 min 14.3 {+-} 5.5 mg U/g dry biomass and dead cells 28.3 {+-} 0.6 mg U/g dry biomass which corresponds to 45% and 90% of total uranium in solution, respectively. During 96 h of incubation with uranium initially living cells died off and with 26.6 {+-} 2.1 mg U/g dry biomass bound similar amounts of uranium compared to dead cells, binding 27.0 {+-} 0.7 mg U/g dry biomass. In both cases, these amounts correspond to around 85% of the initially applied uranium. Interestingly, at a lower and more environmentally relevant uranium concentration of 5 {mu}M, living cells firstly bind with 1.3 {+-} 0.2 mg U/g dry biomass to 1.4 {+-} 0.1 mg U/g dry biomass almost all uranium within the first 5 min of incubation. But then algal cells again mobilize up to 80% of the bound uranium during ongoing incubation in the time from 48 h to 96 h. The release of metabolism related substances is suggested to cause this mobilization of uranium. As potential leachates for algal-bound uranium oxalate, citrate and ATP were tested and found to be able to mobilize more than 50% of the algal-bound uranium within 24 h. Differences in complexation of uranium by active and inactive algae cells were investigated with a combination of time-resolved laser-induced fluorescence spectroscopy (TRLFS), extended X-ray absorption fine structure (EXAFS) spectroscopy and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Obtained results demonstrated an involvement of carboxylic and organic/inorganic phosphate groups in the uranium complexation with varying contributions dependent on cell status, uranium concentration and pH.

  2. Effects of plant growth regulators, carbon sources and pH values on callus induction in Aquilaria malaccensis leaf explants and characteris-tics of the resultant calli

    Institute of Scientific and Technical Information of China (English)

    Shashita JAYARAMAN; Nurul Hazwani DAUD; Rasmina HALIS; Rozi MOHAMED

    2014-01-01

    The endangered tropical tree, Aquilaria malaccensis, produces agarwood for use in fragrance and medicines. Efforts are currently un-derway to produce valuable agarwood compoundsn tissue culture. The purpose of this study was to develop an optimal growth medium, specif-ically, the best hormone combination for callus suspension culture. Using nursery-grown A. malaccensis, sterilized leaf explants were first incu-bated on basic Murashige and Skoog (MS) gel medium containing 15g/L sucrose and at pH 5.7. Different auxin types including 1-naphthaleneacetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), and indole-3-butyric acid (IBA), were tested at various concentrations (0.55, 1.1 and 1.65 µM) using the basic medium. Leaf explants were incubated for 30 days in the dark. Callus induced by 1.1 µM NAA had the highest biomass dry weight (DW) of 17.3 mg;however the callus was of a compact type. This auxin concentration was then combined with either 6-benzylaminopurine (BAP) or kinetin at 0.55, 1.1, 2.2 or 3.3 µM to induce growth of friable callus. The 1.1µM NAA+2.2µM BAP com-bination produced friable callus with the highest biomass (93.3mg DW). When testing the different carbon sources and pHs, sucrose at 15g/L and pH at 5.7 yielded highest biomasses at 87.7mg and 83mg DW, respec-tively. Microscopic observations revealed the arrangement of the friable cells as loosely packed with relatively large cells, while for the compact callus, the cells were small and densely packed. We concluded that MS medium containing 15 g/L sucrose, 1.1 µM NAA + 2.2 µM BAP hor-mone combination, and a pH of 5.7 was highly effective for inducing friable callus from leaf explants of A. malaccensis for the purpose of establishing cell suspension culture.

  3. Versatility of heme coordination demonstrated in a fungal peroxidase. Absorption and resonance Raman studies of Coprinus cinereus peroxidase and the Asp245-->Asn mutant at various pH values.

    Science.gov (United States)

    Smulevich, G; Neri, F; Marzocchi, M P; Welinder, K G

    1996-08-13

    The pH dependence of the electronic absorption and resonance Raman (RR) spectra of FeIII and FeII forms of Coprinus cinereus peroxidase (CIP) and its Asp245-->Asn (D245N) mutant has been examined in detail. The spectral data were obtained in the pH range 3.8-12.0. These spectra were used to assess the spin and ligation states of the heme via the porphyrin marker band frequencies and the wavelengths of the absorption maxima, especially that of the band (CT1) due to the charge transfer from the porphyrin to the heme iron via the a' 2u(pi)-->eg (d pi) electronic transition. The RR spectra were obtained by using different excitation wavelengths and polarized light. The data obtained for ferric CIP show that two pH-induced structural transitions exist. At acid pH the Soret and the CT1 absorption maxima occur at 394 and 652 nm, respectively, compared with the values of 403 and 649 nm observed at neutral pH. The electronic data indicate that at acid pH the proximal Fe-Im bond might be weakened or ruptured, and the RR spectra show a new species (5-c HS) different from the normal neutral 5-coordinate high-spin (5-c HS) heme. At pH 12.0, the protein converts to a 6-coordinate low-spin (6-c LS) heme with a hydroxyl ligand coordinated in the sixth position of the heme iron and strongly hydrogen-bonded with the positively charged guanidinium group of the distal Arg51 residue. Replacement of the aspartate carboxylate group of Asp245, which acts as hydrogen-bond acceptor to the proximal His183 ligand of the heme Fe, with a carboxamide group of an asparagine residue has a profound influence on the heme coordination. The RR spectra of the Fe(II) form of this mutant at both neutral and alkaline pH values show a band at 204 cm-1 assigned to the Fe-His stretch associated with a fairly weak or non-hydrogen-bonded imidazole. The ferric form of the mutant shows a great variability in coordination and spin states upon pH titration. Between pH 8.8 and 3.8 the spectra are mainly

  4. Effect of pH values on surface modification and solubility of phosphate bioglass-ceramics in the CaO-P 2O 5-Na 2O-SrO-ZnO system

    Science.gov (United States)

    Li, Xudong; Cai, Shu; Zhang, Wenjuang; Xu, Guohua; Zhou, Wei

    2009-08-01

    The bioactive glass-ceramics in the CaO-P 2O 5-Na 2O-SrO-ZnO system were synthesized by the sol-gel technique, and then chemically treated at different pH values to study the solubility and surface modification. Samples sintered at 650 °C for 4 h consisted of the crystalline phase β-Ca 2P 2O 7 and the glass matrix. After soaking in the solution at pH 1.0, the residual glass matrix on the surface appeared entirely dissolved and no new phase could be detected. Whereas at pH 3.0, web-like layer exhibiting peaks corresponding to CaP 2O 6 was formed and covered the entire surface of the sample. When conducted at pH 10.0, only part of the glass matrix was dissolved and a new phase Ca 4P 6O 19 was precipitated, forming the petaline layer. The chemical treatment can easily change the surface morphologies and phase composition of this bioactive glass-ceramics. The higher level of surface roughness resulting from the new-formed layer would improve the interface bonding and benefit for cell adhesion.

  5. 生物质酶催化过程中pH值的非线性控制%Nonlinear control of pH value in biomass catalytic process

    Institute of Scientific and Technical Information of China (English)

    何献忠

    2013-01-01

    The pH neutralization process has the highly nonlinear characteristic, when you add neutralizer or interference, pH value near the neutralization point changes a lot, while the pH value in the else points are opposite. It is very difficult to control. According to the characteristics of the pH controls in enzyme catalysis, using a parameter adaptive state controller and Hammerstein model control strategies, employing recursive least squares parameter estimation, static nonlinear characteristics of the controller upside down process non-linear part of the compensation and Hammerstein model is used to design the nonlinear model predictive control algorithm. Compared with other controller state for a difficult to control process this has a very good effect. The system engages in uncertainties real-time compensation, so as to improve the enzyme catalytic process in the stability of the enzyme activity. When the temperature random variation occurred, we carried out various controls in the field experimental study, in the enzyme-catalyzed process in the pilot test. Due to the mutual coupling of the temperature and pH in the catalytic process. The enzyme catalysis in the process of test, and the reaction time of 30 minutes and the simple PID control of the pH value of the large fluctuation, resulting in a big decrease in enzyme activity. The model reference adaptive controller under the control of the pH value of the wave is small, thus leading to a small decline in the range of enzyme activity, so as to enhance the catalytic process of the stability of the enzyme activity. In this way, converted into an approximate linear control for the pH of the enzyme catalysis process control not only enables the pH value highly nonlinear control, and automatically changes the controller tuning parameters, and solves the high degree of pH neutralization process linear control difficulties, but also improves the accuracy of the pH control in the enzyme catalysis process. pH

  6. pH值对右旋布洛芬体外透皮性能的影响研究%Effect of pH Value on in Vitro Percutaneous Permeability for Dextral Ibuprofen

    Institute of Scientific and Technical Information of China (English)

    刘丽清; 于秋菊; 谢茵; 任国莲; 石恩娴; 田青平

    2011-01-01

    目的:研究pH值对右旋布洛芬(DI)体外透皮性能的影响,为其透皮给药制剂的开发提供实验依据.方法:建立DI的高效液相色谱分析方法,测定其在水和不同pH的磷酸盐缓冲液(PBS)中的平衡溶解度;用摇瓶法测定DI的正辛醇溶液在正辛醇饱和蒸馏水与不同pH的PBS中的表现油水分配系数;以稳态渗透速率(Js)和渗透系数(Ps)为评价指标,检测不同pH的PBS对DI体外透皮性能的影响.结果:32℃时,DI在水中难溶;在pH7.4的PBS中平衡溶解度、Js、Ps均最大,表观油水分配系数极小,分别为5 421.6 μg·mL-1、339.97 μg·cm-2·h-1、0.063 cm·h-1、0.17.结论:pH值对DI体外透皮性能有很大影响,pH7.4时DI有较高的溶解度、脂溶性及较理想的皮肤通透性.%OBJECTIVE: To study the effect of pH value on in-vitro percutaneous permeability of dextral ibuprofen (DI) and to provide experimental basis for the development of percutaneous agent. METHODS: HPLC method was established to determine the equilibrium solubility of DI in water and phosphate buffer solution (PBS) with different pH values. Shaking-flask method was used to measure the apparent oil-water distribution coefficient of DI in the n-octyl alcohol saturated water or PBS with different pH values. The effect of PBS with different pH values on in-vitro percutaneous permeability of DI was evaluated using the steady-state permeation rate (J.) and permeation coefficient (P.) as index. RESULTS: At 32 ℃, DI was hardly soluble in water; the equilibrium solubility, J., P. of DI in PBS with pH 7.4 were the highest while apparent oil-water distribution coefficient was close to minimum value. They were 5 421.6 μg·mL-1, 339.97 μg·cm-2·h-1, 0.063 cm·h-1, 0.17, respectively. CONCLUSION: The in-vitro percutaneous permeability of DI is greatly influenced by the pH of media. Adjusting pH to 7.4, higher solubility and liposolubility of drug are maintained as well as percutaneous permeability.

  7. Study on the Influence of the pH Value on the Interactions between Fluoroquinolones and Bovine Serum Albumin%pH对氟喹诺酮药物与BSA之间相互作用影响的研究

    Institute of Scientific and Technical Information of China (English)

    刘世旺; 徐艳霞; 夏小环

    2009-01-01

    The interactions between four fluoroquinolones (pefloxacin, levoxfloxacin, oxfloxacin, and ciprofloxacin) and bovine serum albumin(BSA) were studied by capillary zone electrophoresis. The migration behaviors of the fluoroquinolones were investigated in a series of running buffers containing different concentrations of BSA. The binding constants of the fluoroquinolones and BSA were calculated at pH values of the running buffer of 6.8, 7.4 and 8.0, respectively. Results showed that pH value has a great influence upon the interactions between fluoroquinolones and BSA, and the binding constants of four fluoroquinolones and BSA reach the maximum at pH 6.8. The binding constants decrease gradually with the increasing of the pH value. The binding type and site between fluoroquinolones and BSA were investigated in detail. Study on the influence of pH value on the binding constants would be very helpful for the drugs' pharmacokinetic profiles evaluation and further drug discovery.%采用毛细管区带电泳法,通过测定在不同pH值、不同牛血清白蛋白(BSA)浓度缓冲溶液的条件下药物迁移时间的变化,并分别计算出了pH为6.8、7.4和8.0时培氟沙星、左氧氟沙星、氧氟沙星、环丙沙星等四种氟喹诺酮类药物与BSA相互作用的结合常数.结果表明:pH对结合常数有较大影响,四种药物分子结合常数的最大值均出现在pH=6.8时,并随着pH的增大,结合常数值明显下降.根据实验结果,还对四种氟喹诺酮类药物与BSA之间相互作用的类型、作用位置进行了分析探讨.研究结果对于进一步阐明药用机理并迅速开发出更高效的广谱抗菌药物具有较强的理论意义.

  8. 不同pH值L-精氨酸诱导小鼠急性胰腺炎模型效果观察%Effect of Acute Pancreatitis Model Induced by Different pH Values of L-arginine

    Institute of Scientific and Technical Information of China (English)

    石占利; 陈芝芸; 高凯

    2013-01-01

    Objective: To investigate the effect of acute pancreatitis model induced by different pH values of L-arginine. Methods: Seventy BABL/C mice were randomly divided into 3 groups. Two groups were treated with L-arginine solution of pH 11 and pH 8,respectively. L-arginine solutions were intraperitoneally injected 250mg/100g body weight twice at an interval of 1 hour. Another group served as control and was treated with same vol⁃ume of saline. Serum amylase was determined and pancreas pathological score and mortality rate were calculated in all groups at the time of 24 and 48 hours after injection. Results: Compared with the control group, the se⁃rum amylase levels were significantly increased in the pH11 group and pH8 group at the time of 24 and 48 hours(P<0.01). Compared with the pH11 group, the serum amylase levels in the pH8 group were significantly de⁃creased at the time of 24h and 48h(P<0.01), meanwhile, the pancreas pathological score and mortality rate in the pH8 group were also decreased significantly at both time points(P<0.05). Conclusion: The pH value of L-ar⁃ginine solution has a significant impact on the degree of pancreatic injury and animal mortality. The strong alka⁃line of L-arginine which does damage to abdominal organs is an important reason for instability of acute pancre⁃as model.%  目的:观察不同pH值L-精氨酸腹腔注射诱导急性胰腺炎模型的效果.方法:70只BABL/C小鼠,随机分为pH11组、pH8组和对照组,分别采用pH值为11的20%L-精氨酸溶液、pH值为8的20%L-精氨酸溶液、等体积生理盐水,间隔1h 2次小鼠腹腔内注射(250mg/100g体质量)的方法.在24h和48h分别观测三组小鼠的血清淀粉酶、胰腺病理学评分,并统计死亡率.结果:pH11组、pH8组小鼠在24h和48h的血清淀粉酶水平均较对照组显著升高(P<0.05,P<0.01);PH11组较pH8组24h和48h血清淀粉酶水平均升高更明显(P<0.01);pH8组24h和48h胰腺病理评分均较pH11

  9. 浙江省标准农田土壤酸碱度现状及改良措施%Status of Soil pH Values of Standardized Farmlands in Zhejiang Province and Its Improvement Measures

    Institute of Scientific and Technical Information of China (English)

    边武英

    2009-01-01

    [Objective] The aim was to investigate the status of soil pH values of standardized farmlands in Zhejiang province and put forward the corresponding improvement measures. [Method] With the standardized farmlands of 83 counties in Zhejiang province as sampling points, the soil samples were conducted for collection, processing and storage according to referenced to NY/T 1121.1 and soil pH values were measured by using distilled water extraction and glass electrode. The pH values of standardized farmland of different types in different regions were compared. [Result] The percentage which soil pH values of standardized farmlands and paddy at all levels accounted presented a trend of reducing at the middle and rising at two ends, and the rising amplitude of the proportion of acid soils was more than that of alkaline soils. Compared with the structure of 2nd general soil survey,the ratio of farmlands with soil pH values of or lower than 5.5 was increased by 20.71%, and that with soil pH of or lower than 4.5 of farmlands was increased by 1.71%. There were obvious differences of the pH value of standardized farmland in different geomorphologic types and the order was as follows: coastal plain > water net plain > valley plain > hilly area. [Conclusion] Measures such as liming, increasing organic fertilizer and extending soil testing and fertilizer recommendation should be taken to prevent the phenomenon of soil acidification of farmland in Zhejiang Province fundamentally.%[目的] 调查浙江省标准农田土壤酸碱度的现状,提出相应的改良措施.[方法] 以浙江省83个县市区的标准农田为取样点,参照NY/T 1121.1对土壤样品进行采集、处理和贮存,采用蒸馏水浸提玻璃电极法测定土壤pH值,对全省不同类型、不同区域的标准农田pH值进行比较.[结果] 标准农田土壤和水稻土pH值各级所占百分比呈现中间降低两头上升的趋势,且酸性土壤所占比例上升幅度大

  10. Iron chelating active packaging: Influence of competing ions and pH value on effectiveness of soluble and immobilized hydroxamate chelators.

    Science.gov (United States)

    Ogiwara, Yoshiko; Roman, Maxine J; Decker, Eric A; Goddard, Julie M

    2016-04-01

    Many packaged foods utilize synthetic chelators (e.g. ethylenediaminetetraacetic acid, EDTA) to inhibit iron-promoted oxidation or microbial growth which would result in quality loss. To address consumer demands for all natural products, we have previously developed a non-migratory iron chelating active packaging material by covalent immobilization of polyhydroxamate and demonstrated its efficacy in delaying lipid oxidation. Herein, we demonstrate the ability of this hydroxamate-functionalized iron chelating active packaging to retain iron chelating capacity; even in the presence of competing ions common in food. Both immobilized and soluble hydroxamate chelators retained iron chelating capacity in the presence of calcium, magnesium, and sodium competing ions, although at pH 5.0 the presence of calcium reduced immobilized hydroxamate iron chelation. A strong correlation was found between colorimetric and mass spectral analysis of iron chelation by the chelating packaging material. Such chelating active packaging may support reducing additive use in product formulations, while retaining quality and shelf life.

  11. Effects of pH Value on Resin Deposition with the Presence of Calcium Ion%pH值对钙离子存在下树脂沉积的影响

    Institute of Scientific and Technical Information of China (English)

    王旭; 詹怀宇; 陈港; 罗巨生

    2004-01-01

    The effects of pH value on resin deposition with the presence of CaTM were studied by usingthe device of "Rotating-mixer" and the method of GC-MS analysis. It is found that the decrease of pHvalue results in resin deposition and pH7.0 is the turning point. The deposits were analyzed by GC-MSafter being separated into combined resins and free resins. Experimental results show that calciumsoaps and free resins contribute together to deposits formation. The combined resins would change intofree resins at low pH and high temperature. Acidic components play an important role in soapsformation and the soaps of fatty acids are more stable at low pH value.%采用旋转搅拌装置和GC-MS法研究了pH值对钙离子存在下树脂沉积的影响.发现pH值的降低会导致树脂的沉积,pH7.0是转折点.将这些树脂分离成结合树脂和游离树脂后进行GC-MS分析,结果表明,钙皂和游离树脂对沉积物的形成有共同的贡献,结合树脂在低pH值和高温下转变为游离树脂.酸性组分对钙皂的形成起重要作用,而脂肪酸皂在低pH值下更稳定.

  12. Groundwater quality and the relation between pH values and occurrence of trace elements and radionuclides in water samples collected from private wells in part of the Kickapoo Tribe of Oklahoma Jurisdictional Area, central Oklahoma, 2011

    Science.gov (United States)

    Becker, Carol J.

    2013-01-01

    From 1999 to 2007, the Indian Health Service reported that gross alpha-particle activities and concentrations of uranium exceeded the Maximum Contaminant Levels for public drinking-water supplies in water samples from six private wells and two test wells in a rural residential neighborhood in the Kickapoo Tribe of Oklahoma Jurisdictional Area, in central Oklahoma. Residents in this rural area use groundwater from Quaternary-aged terrace deposits and the Permian-aged Garber-Wellington aquifer for domestic purposes. Uranium and other trace elements, specifically arsenic, chromium, and selenium, occur naturally in rocks composing the Garber-Wellington aquifer and in low concentrations in groundwater throughout its extent. Previous studies have shown that pH values above 8.0 from cation-exchange processes in the aquifer cause selected metals such as arsenic, chromium, selenium, and uranium to desorb (if present) from mineral surfaces and become mobile in water. On the basis of this information, the U.S. Geological Survey, in cooperation with the Kickapoo Tribe of Oklahoma, conducted a study in 2011 to describe the occurrence of selected trace elements and radionuclides in groundwater and to determine if pH could be used as a surrogate for laboratory analysis to quickly and inexpensively identify wells that might contain high concentrations of uranium and other trace elements. The pH and specific conductance of groundwater from 59 private wells were measured in the field in an area of about 18 square miles in Lincoln and Pottawatomie Counties. Twenty of the 59 wells also were sampled for dissolved concentrations of major ions, trace elements, gross alpha-particle and gross beta-particle activities, uranium, radium-226, radium-228, and radon-222 gas. Arsenic concentrations exceeded the Maximum Contaminant Level of 10 micrograms per liter in one sample having a concentration of 24.7 micrograms per liter. Selenium concentrations exceeded the Maximum Contaminant Level of 50

  13. pH值对Reppe法生产1,4-丁二醇加氢工艺的影响%Influence of pH Value on Hydrogenation Process for Producing 1, 4 - Butanediol with Reppe Method

    Institute of Scientific and Technical Information of China (English)

    李建立; 刘新波; 罗明周

    2012-01-01

    河南开祥精细化工有限公司4.5万t/a1,4-丁二醇装置采用Reppe法工艺技术。简述了该装置的加氢工艺流程和催化剂特性;建立了低压加氢反应器内物料的pH值与主产物BDO浓度以及产物中乙缩醛含量、羰基数、丁醇含量之间的关联曲线;确立了混合槽物料pH值(pH1)与低压加氢进料槽物料pH值(pH2)以及低压加氢反应器内物料pH值(pH3)三者之间的递减关系。研究结果表明:①将低压加氢反应器内物料pH值控制在7.0-7.5时,催化剂使用条件最佳,主产物BD0的含量最高,且各副产物浓度较低;②通过调整进料槽物料的pH值,可控制加氢反应器内物料的pH值。%The process technology with Reppe method has been adopted in the 1, 4 - Butanediol plant with a capacity of 45,000 t/a in Kaixiang Fine Chemistry Engineering Company Ltd. Author has briefly described the hydrogenation process flow and the characteristic of catalyst in this plant ; has established the relation curves among the medium pH value in low pressure hydrogenation reactor, BOD concentration of product, content of by-product acetal, carbonyl number and butanol content; has determined the progressively decreasing relation among the three parts of medium pH value (pHI) in mixing tank, medium pH value (pH2) in low pressure hydrogenation feed tank and medium value (pH3) in low pressure hydrogenation reactor. Researc- hing result indicates: (1) The operating condition is optimum, with a maximum content of the main products, and a lower concentration of every by-product, in case of tak- ing the medium pH value in low pressure hydrogenation reactor being controlled in 7.0-7.5. (2) The pH value of medium in Hydrogenation reactor can be controlled by means of controlling the pH value of medium in the feed tank.

  14. Correlation between Semen PH Value and Semen Parameters or Biochemical Analyses Results of Seminal Plasma%精液pH值与精液参数及精浆生化的相关性研究

    Institute of Scientific and Technical Information of China (English)

    陈帅垒; 王祖龙

    2012-01-01

    目的 探讨精液pH值与精液参数及精浆生化之间的相关性,明确精液pH值在精液质量检测中所具有的价值.方法 收集河南省中医院中西医结合生殖中心2009年1月-2011年3月资料完整的男性不育症患者精液分析及精浆生化记录616份,建立Excel数据库,采用SPSS 16.0统计软件,对精液pH值与精液参数及精浆生化进行相关性分析.结果 精液pH值和受试者精浆弹性蛋白酶、精液A级精子百分率、前向运动精子百分率及存活精子百分率呈正相关性(P<0.05);与精浆酸性磷酸酶、精浆锌呈负相关性(P<0.05);与年龄、精浆果糖、精浆α-糖苷酶、精液白细胞、精液量、液化时间、精子浓度、正常形态精子数量无明显相关性(P>0.05).结论 精液pH值和精液参数及精浆生化的多项数值均具有相关性,进一步研究精液pH值的影响,对于男性不育症患者的诊疗具有重要意义.%Objective To study the correlation between semen pH value and semen parameters and biochemical analyses results of seminal plasma, and evaluate the value of semen pH in the semen quality test. Methods The semen and biochemical analyses results of 616 male infertility patients in our hospital from January 2009 to March 2011 were collected and analyzed by u-sing SPSS statistical software to evaluate the correlation between semen pH value and semen parameters and biochemical analyses results of seminal plasma. Results The semen PH value was positively correlated to the seminal plasma elastase, rate of grade A sperm,rate of rapid progression motility sperm and sperm viability (P 0. 05) . Conclusion The semen PH value is closely correlated to the semen parameters and biochemical analyses results of seminal plasma. The further study on the influence of semen PH value should improve the diagnosis and treatment of male infertility patients.

  15. Effect of pH Value on Structure and Properties of Anodic Electrodeposited Mn-MoOxide%pH值对阳极电沉积Mn-Mo氧化物结构与性能的影响

    Institute of Scientific and Technical Information of China (English)

    史艳华; 赵杉林; 梁平; 王玲; 关学雷

    2016-01-01

    By correction to the thermodynamic calculation based on E0‐pH diagram of MnSO4‐SO2 -4 ‐H2 O plating system ,effective pH value range for anodic electrodeposition of M nO 2 phase structure materials got clear ,at 363K ,with Mn2+ concentration 0 .2mol · dm -3 .The influence law of the pH values was also obtained based on the characterization of the oxide structure and test of its electro‐chemical performance .The results show that pH value in the 0 .33‐3 .4 range ,with its increase and accordingly the conducive to the effective deposition of MnO2 type Mn‐Mo oxide .However ,although with pH value increasing ,deposition efficiency improves ,the coating quality gets degraded ,especially making the electrocatalytic performance of the oxide obviously deteriorated .It also shows that with pH value of plating solution 0 .5 ,obtained Mn‐Mo oxide has excellent coating quality and high electro‐catalytic activity .The reason is closely related to competition in oxygen evolution reaction during the preparation of the oxide .When pH value is small ,oxygen evolution reaction competition causes the solid‐liquid interface stirring ,the dendritic grow th of oxide gets inhabited and the diffusion layer gets thinning ,w hich promotes the nucleation of oxide on the electrode micro‐surface and makes grain re‐fined ,so as to improves the electrocatalytic performance of oxide .%通过热力学计算修正的 M nSO4‐SO2-4‐H2 O镀液体系平衡电势 E0‐pH图,明确了363K和 M n2+浓度0.2mol · dm -3时M nO2物相结构材料阳极电沉积有效pH值范围,通过对氧化物结构表征及电化学性能测试获得了pH值的影响规律。结果表明:pH值在0.33~3.4时,随着pH值增大,有利于MnO2物相结构Mn‐Mo氧化物的有效析出,但pH值增大虽可提高阳极电沉积效率,却造成镀层质量变差,电催化性能明显劣化,镀液pH=0.5时获得的Mn‐Mo氧化物具有优异的镀层质量和高

  16. 健康妊娠妇女阴道乳酸杆菌及pH变化的研究%The change of vaginal Lactobacilli and pH value in vaginal secretion of healthy women before and after pregnancy

    Institute of Scientific and Technical Information of China (English)

    孙文平; 罗红; 陈晨; 綦霞; 杨光; 赵春艳

    2011-01-01

    目的 研究健康妊娠妇女阴道乳酸菌数量及pH的变化与妊娠时间的关系.方法 选择20例健康非妊娠妇女,60例健康妊娠妇女(其中早期妊娠、中期妊娠及晚期妊娠各20例)阴道分泌物进行乳酸杆菌数量检测及pH测定,并对乳酸杆菌产生过氧化氢的情况进行检测.结果 随着妊娠时间的增加,乳酸杆菌的数量明显增高,伴随阴道分泌物的pH逐渐降低.结论 乳酸杆菌与健康妊娠妇女阴道的生物屏障和酸性环境的维持有重要关系.%Objective To study the relationship between pregnancy time and the changes of the number of vaginal lactic acid bacteria and pH value in vaginal secretions. Method 20 healthy non-pregnant women, 60 healthy pregnant women ( including early pregnancy, mid-pregnancy and late pregnancy, each 20 cases) were selected. The number of vaginal lactobacilli and pH value in vaginal secretions were detected, and the production of hydrogen peroxide by Lactobacillus were detected. Result With the time of pregnancy increasing, the number of lactobacilli increased significantly, while the pH value of vaginal secretion decreased. Conclusion Lactobacilli in vaginal secretions of healthy pregnant women are the biological barriers which maintein the acidic vaginal environment.

  17. pH值对纯菌种Ethanologenbacterium sp.nov R3产氢的影响%Effects of pH value on fermentative biohydrogen production with Ethanologenbacterium sp. nov R3 in continous stirred tank reactor

    Institute of Scientific and Technical Information of China (English)

    史沫男; 林永波; 邓洁璇; 陈红; 李永峰

    2011-01-01

    In this paper, Ethanologenbacterium sp. nov R3 was used as research microbe which was inoculated from continuous stirred tank reactor (CSTR). The temperature and HRT of CSTR were controlled at ( 35 ± 1 ) ℃ and 8 h respectively. The effects of influent pH value on fermentative biohydrogen production with R3 were showed in this paper. When influent pH value was 5.5, the capacity of R3 to produce hydrogen was best. In this influent pH value, biogas yield and hydrogen content respectively achieved 6.85 ~ 8.86 L/d and 59.44% ~65. 13%. COD removal and effluent pH value were mainly stable at 26% and 4.38.The average concentration of ethanol and acetic acid in VFAs were respectively 706 mg/L and 446 mg/L. R3 maintained ethanol - type fermentation characteristics all along.%以Ethanologenbacterium sp.nov R3(以下称为R3)为研究对象,将其接种入连续搅拌槽式反应器(continuous stirred tank reactor,CSTR)中进行发酵产氢实验,以葡萄饮料废水为底物,温度控制在(35±1)℃,水力停留时间为8 h,探讨了不同的进水pH值对纯菌种R3连续流厌氧发酵生物制氢的影响.实验证明,当进水pH值为5.5时R3的厌氧发酵产氢能力最强.此时,产气量和氢气体积分数分别达到了6.85~8.86L/d和59.44%~65.13%,COD去除率稳定在26%左右,出水pH值稳定在4.38左右.在总挥发酸中,乙醇和乙酸的平均质量浓度分别是706mg/L和446 mg/L.整个过程中,R3始终保持乙醇型发酵特性.

  18. Effects of temperature and pH value on Castanea henryi starch retrogradation%贮藏温度与pH对锥栗淀粉糊回生的影响

    Institute of Scientific and Technical Information of China (English)

    童金华

    2011-01-01

    Taking starch of Castanea henryi as the raw material,the effects of different storage temperatures and pH values on retrogradation of C.henryi starch were observed by the enzymatic experiment.The results showed that the starch paste was easy for retrogradation at the temperature of 4 ℃,and the retrogradation percentage reached 9.76% after 24 hours.Meanwhile C.henryi starch paste was easy for retrogradation when pH was 5 and 7,while the retrogradation percentage decreased when pH was 3 and 9.%以锥栗淀粉为原料,采用酶法研究不同贮藏温度和pH对锥栗淀粉糊回生的影响。结果表明:锥栗淀粉糊在贮藏温度4℃时易回生,1 d后的淀粉糊回生率已达9.76%;pH为5和7时,锥栗淀粉糊易回生,pH为3和9时锥栗淀粉糊回生延缓。

  19. 24-hour esophageal pH-monitoring in children suspected of gastroesophageal reflux disease: Analysis of intraesophageal pH monitoring values recorded in distal and proximal channel at diagnosis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To assess values of 24-h esophageal pH-monitoring parameters with dual-channel probe (distal and proximal channel) in children suspected of gastroesophageal reflux disease (GERD).METHODS: 264 children suspected of gastroesophageal reflux (GER) were enrolled in a study (mean age χ = 20.78 ± 17.23 mo). The outcomes of this study,immunoallerrgological tests and positive result of oral food challenge test with a potentially noxious nutrient,enabled to qualify children into particular study groups.RESULTS: 32 (12.1%) infants (group 1) had physiological GER diagnosed. Pathological acid GER was confirmed in 138 (52.3%) children. Primary GER was diagnosed in 76 (28.8%) children (group 2) and GER secondary to allergy to cow milk protein and/or other food (CMA/FA) in 62 (23.5%) children (group 3). 32(12.1%) of them had CMA/FA (group 4-reference group),and in remaining 62 (23.5%) children neither GER nor CMA/FA was confirmed (group 5). Mean values of pH monitoring parameters measured in distal and proximal channel were analyzed in individual groups. This analysis showed statistically significant differentiation of mean values in the case of: number of episodes of acid GER,episodes of acid GER lasting > 5 min, duration of the longest episode of acid GER in both channels, acid GER index total and supine in proximal channel. Statistically significant differences of mean values among examined groups, especially between group 2 and 3 in the case of total acid GER index (only distal channel) were confirmed.CONCLUSION: 24-h esophageal pH monitoring confirmed pathological acid GER in 52.3% of children with typical and atypical symptoms of GERD. The similar pH-monitoring values obtained in group 2 and 3 confirm the necessity of implementation of differential diagnosis for primary vs secondary cause of GER.

  20. 土壤类型与酸碱度对紫杉生长发育的影响%Effect of Soil Types and pH Value on Growth of Taxus cuspidata

    Institute of Scientific and Technical Information of China (English)

    唐晓杰; 白玉文; 张涛; 程广有

    2015-01-01

    为了探讨土壤类型与酸碱度对紫杉生长发育的影响,选择沙壤土、旱田土、腐殖土、河沙和苔藓等5种土壤类型(沙壤土pH分别为4.5,5.0,5.5,6.0,6.5,7.0,7.5,8.5)进行盆栽试验.结果表明:不同类型土壤对紫杉生长影响不同,在腐殖质中高生长最好,新梢长度达16.9 cm;其次是沙壤土,新梢长度达14.5 cm;在腐殖土和沙壤土中栽培的紫杉总根长度较大,河沙与苔藓基质中侧根和白根数量多.盆土酸碱度影响紫杉生长,土壤pH在5.5~7.0时,树高生长量差异不大,新梢长度为12.6~13.3 cm;当土壤pH小于4.5或大于7.5时,高生长受到抑制;土壤pH在5.5~7.0时,总根长度和侧根数量最多.%In order to evaluate effect of soil types and pH value on growth of of Taxus cuspidata, sandy soil, upland soil,humus soil,river sand and moss were selected to cultivate,pH value was adjusted to 4. 5,5. 0,5. 5, 6. 0,6. 5,7. 0,7. 5 and 8. 5 respectively. These results indicated that there were significant variations of yew growth in different soils. The height of yew seedlings which planted in humus soil and sandy soil were superior to that of other soils,whose growth yields were 16. 9 cm and 14. 5 cm respectively. The root length of seedlings which planted in humus soil and sandy soil were superior to that of other soils. The amount of lateral root and albino root of seedlings which planted in river sand and moss were greater than those of other soils. There were significant variations of yew growth in different pH values. The height yield was no significant variation when the soil pH value was from 5. 5 to 7. 0,whose growth yield was from 12. 6 to 13. 3 cm. Nevertheless,the height yield was restrained when the soil pH value was less than 4 . 5 or greater than 7 . 5 . The root length and lateral root number was maximum when the soil pH value was from 5 . 5 to 7 . 0 .

  1. 凝乳粒的pH值对融化干酪品质的影响%Effect of curd particle's pH value on the quality of processed cheese

    Institute of Scientific and Technical Information of China (English)

    霍建新; 王燕; 原慧艳; 王演; 白彩艳; 李明

    2015-01-01

    研究了凝乳粒的pH值对融化干酪的品质的影响.通过对融化干酪主要成分、感官评价、质构分析和微观结构的测定,比较了凝乳粒pH值为6.0、5.8、5.6、5.4、5.2对融化干酪品质的影响.结果表明:随着pH值的降低,融化干酪的脂肪含量和蛋白质含量逐渐减少,含水率增加;凝乳粒pH值为5.6时,切面光滑平整、组织状态均一、口感细腻;具有最高的恢复性,硬度适中,较低的咀嚼度、胶着性、黏聚性和弹性;融化干酪的网络结构更加密实,质地均匀,融化干酪整个体系有最佳的乳化效果.%The effect of the curd particle' s pH value on the quality of processed cheese was studied.Combined with main compositions,sensory evaluation,texture profile analysis and electron scanning spectroscopy,we investigated the effects of pH value 6.0,5.8,5.6,5.4,5.2 on the quality of processed cheese,respectively.Results showed that with pH values decreasing,processed cheese exhibited higher moisture,lower fat content.At pH 5.6,processed cheese had a smooth texture,uniform tissue and delighted taste,higher resilience,moderate hardness,low chewiness,low gumminess,cohesiveness,and springiness.The network between proteins was more closed and the structure was more uniform in the processed cheese.The emulsification was also very good.

  2. 肝硬化患者血总胆汁酸水平、粪便 pH 值的临床意义%Clinical value of serum total bile acid and fecal pH in patients wi th hepatic ci rrhosis

    Institute of Scientific and Technical Information of China (English)

    吴旭; 代敏涛; 李卓

    2014-01-01

    Objective]To investigate the clinical value of serum total bile acid (TBA )and fecal pH in Child-pugh classification in patients with hepatic cirrhosis.[Methods]Seventy patients with hepatic cirrho-sis were enrolled and divided into three groups according to Child-pugh classification :A group(A grade ,13 cases) ,B group(B grade ,34 cases) ,C group(C grade ,23 cases) ,respectively.And 40 patients with chronic gastritis were enrolled as control.Automatic biochemistry analysator was used to measure serum TBA.Fecal pH value was detected by short range pH paper.[Results]The levels of fecal pH and serum TBA were signifycantly higher in patients with hepatic cirrhosis than those in control group (P0.05).No significant correlation was found between serum TBA ,fecal pH and different causes of hepatic cirrhosis(P> 0.05).[Conclusion]Serum TBA ,fecal pH is one of the sensi-tive indexes refectiong cell damage of hepatic cirrhosis.Fecal pH is affected by many factors ,w hich has less value than serum TBA on predicting the prognosis and degree of liver function in patients with he-patic cirrhosis.%[目的]探讨血清胆汁酸(TBA)水平和粪便pH值在肝硬化中的临床价值。[方法]对70例肝硬化患者(肝硬化组)、40例慢性胃炎患者(对照组)采用全自动生化分析仪检测其 TBA、精密pH试纸检测其粪便pH值。[结果]肝硬化组患者外周血 TBA水平、粪便 pH值分别为(52.88±47.88)μmol/L、6.88±0.71,对照组分别为(8.695±4.70)μmol/L、5.860±0.27;2组比较,血清TBA水平及粪便pH值均差异有统计学意义(P<0.01)。肝硬化组患者随着Child-pugh分级升高而TBA水平升高,各级间比较差异有统计学意义(P<0.05);但不同Child-pugh分级患者粪便pH值无改变。外周血TBA水平、粪便pH值与肝硬化病因无明显相关性。[结论]TBA、粪便pH值是反映肝硬化患者肝细胞损害的敏感指标之一,由于影响粪便pH值的因素较多,

  3. 一种基于混合神经网络的浮选pH值预测模型%Prediction Model for pH Value in Flotation Process Based on Hybrid Neural Network

    Institute of Scientific and Technical Information of China (English)

    唐朝晖; 杜金芳; 陈青

    2012-01-01

    矿物浮选过程中,矿浆pH值作为影响浮选效果的一个重要因素,是实现浮选过程监视及优化控制的一个重要参量.目前的pH值测定仪存在交叉污染、测量滞后等问题,难以获得实时准确的pH值.为使浮选运行在最优状态,在泡沫图像特征提取的基础上,提出一种基于自适应遗传混合神经网络的预测模型,该模型首先利用主元分析(PCA)方法对提取的多个图像特征进行降维,然后采用自适应遗传混合神经网络(AGA-HNN)建立PH值预测模型.最后将该模型应用于浮选现场,预测结果能够实时跟踪实际值,根据预测值实时调整工况条件,改善了浮选效果,提高了浮选效率.%In mineral flotation process, pH value is one of the flotation elements which affect the flotation performance significantly. It is very important for flotation process monitoring and optimized controtl. At present, pH determinator has the problem of cross contamination , measurement lag, and so on. So it is difficult to obtain real lime and accurate pH value. To make flotation limning in an optimal slate, a novel prediction model is proposed in this paper based on adaptive genetic hybrid neural network after extracting several image features. Firstly, feature dimension reduction is done by principal component analysia( PCA). Then prediction model is built through a-daptive genetic hybrid neural network( AGA-HNN). Finally, the model is applied to flotation field. Predicted value can well trace the actual value. At the same time, working condition is adjusted according to the predicted value. As a result, the flotation performance and efficiency are improved obviously.

  4. Using Dissolved Oxygen,Oxidation Reduction Potential and pH Value for Control Nitrogen Removal in SBR Process%以DO、ORP、pH控制SBR法的脱氮过程

    Institute of Scientific and Technical Information of China (English)

    高景峰; 彭永臻; 王淑莹; 曾薇; 隋铭皓

    2001-01-01

    In order to achieve on-line fuzzy control of nitrogen removal inSBR,a brewery wastewater was treated in a SBR.Variation patterns of ORP,DO and pH value during the removal of organic matters,nitrification and denitrification were studied in detail with different influent concentrations of ammonia nitrogen.The results show that the characteristic points and platforms of DO,ORP and pH value are repeated very well,and can be used as process control parameters for the removal of organic matters,nitrification and denitrification in a SBR process.%为实现SBR法脱氮在线模糊控制,以啤酒废水为研究对象,通过不同进水混合液氨氮浓度的试验,详细地研究了SBR法在去除有机物和硝化、反硝化过程中DO、ORP、pH的变化规律。试验表明,DO、ORP、pH的特征点和平台的重现性很好,可以作为SBR法去除有机物,硝化,反硝化的过程控制参数。

  5. Effects of chloride ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength martensitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    Hui-yan Li; Chao-fang Dong; Kui Xiao; Xiao-gang Li; Ping Zhong

    2016-01-01

    The effects of Cl− ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength marten-sitic stainless steel (UHSMSS) were investigated by a series of electrochemical tests combined with observations by stereology microscopy and scanning electron microscopy. A critical Cl− ion concentration was found to exist (approximately 0.1wt%), above which pitting occurred. The pitting potential decreased with increasing Cl− ion concentration. A UHSMSS specimen tempered at 600°C exhibited a better pitting cor-rosion resistance than the one tempered at 400°C. The corrosion current density and passive current density of the UHSMSS tempered at 600°C decreased with increasing pH values of the corrosion solution. The pits developed a shallower dish geometry with increasing polariza-tion potential. A lacy cover on the pits of the UHSMSS tempered at 400°C accelerated pitting, whereas corrosion products deposited in the pits of the UHSMSS tempered at 600°C hindered pitting.

  6. Effects of chloride ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength martensitic stainless steel

    Science.gov (United States)

    Li, Hui-yan; Dong, Chao-fang; Xiao, Kui; Li, Xiao-gang; Zhong, Ping

    2016-11-01

    The effects of Cl- ion concentration and pH values on the corrosion behavior of Cr12Ni3Co12Mo4W ultra-high-strength martensitic stainless steel (UHSMSS) were investigated by a series of electrochemical tests combined with observations by stereology microscopy and scanning electron microscopy. A critical Cl- ion concentration was found to exist (approximately 0.1wt%), above which pitting occurred. The pitting potential decreased with increasing Cl- ion concentration. A UHSMSS specimen tempered at 600°C exhibited a better pitting corrosion resistance than the one tempered at 400°C. The corrosion current density and passive current density of the UHSMSS tempered at 600°C decreased with increasing pH values of the corrosion solution. The pits developed a shallower dish geometry with increasing polarization potential. A lacy cover on the pits of the UHSMSS tempered at 400°C accelerated pitting, whereas corrosion products deposited in the pits of the UHSMSS tempered at 600°C hindered pitting.

  7. INFLUÊNCIA DE DIFERENTES pH DO MEIO DE AQUECIMENTO NA RESISTÊNCIA TÉRMICA DE Neosartorya fischeri ISOLADO DO PROCESSO PRODUTIVO DE NÉCTAR DE MAÇÃ INFLUENCE OF DISTINCT PH VALUES IN THE THERMAL RESISTANCE OF NEOSARTORYA FISCHERI ISOLATED FROM APPLE NECTAR PROCESSING

    Directory of Open Access Journals (Sweden)

    B. C. M. SALOMÃ?O

    2008-08-01

    Full Text Available

    A resistência térmica de ascósporos de N. fischeri, isolados do concentrado de maçã, foi verificada utilizando-se tubos TDT (Thermal Death Time selados, e suco de maçã, a diferentes pHs, como meio de aquecimento. As curvas obtidas a 80, 85 e 90°C mostraram um “ombro” inicial evidenciando comportamento de morte não logarítmica. Assim, o cálculo dos parâmetros cinéticos foi realizado através da linearização das mesmas. Os valores de “1/k” obtidos em pH 2,5 foram 81,3; 16,0 e 0,9 minutos para 80, 85 e 90°C, respectivamente; em pH 3,5 foram de 153,8; 22,0 e 1,0 minutos e em pH 4,5 foram de 312,5; 38,6 e 2,2 minutos, para as mesmas respectivas temperaturas. O valor de Z* (equivalente a Z foi 5,0°C a pH 2,5 e o mesmo valor (4,6°C foi encontrado em pH 3,5 e 4,5. Os valores de esterilização F(95°C nos pHs 2,5; 3,5 e 4,5 foram respectivamente 44,6; 36,8, e 77,0 segundos, considerando-se a redução da população inicial em 6 ciclos logarítmicos. Como o tratamento térmico comercial normalmente aplicado ao suco de maçã é de 95°C/30s, pode-se concluir que este não será suficientemente seguro para atingir a probabilidade de sobrevivência de 1 ascósporo a cada 105 embalagens, o que seria esperado.

    The heat resistance of N. fischeri ascospores isolated from apple concentrate was verified using closed TDT (Thermal Death Time tubes, and apple juice as heating medium (at different pHs. The curves at 80, 85 and 90°C showed an initial “shoulder” due to non logarithmic death behavior. Then, the kinetic parameters calculation was performed by linearization .The 1/k values obtained at pH 2.5 were 81.3, 16 and 0.9 minutes at 80, 85 and 90°C, respectively; at pH 3.5 were

  8. Nitrate Content and pH- value Changes in Process of Salting Cucumber%黄瓜腌制过程中亚硝酸盐含量及pH值变化

    Institute of Scientific and Technical Information of China (English)

    周强; 刘蒙佳; 黄月妹

    2012-01-01

    以黄瓜为原料,测定在不同条件下保藏的泡菜中亚硝酸盐含量度pH值.研究结果表明,腌制初期泡菜中亚硝酸盐含量呈上升趋势,第3、4天泡菜中亚硝酸盐含量达到最大值,之后又逐渐下降.7d后泡菜中亚硝酸盐含量符合国标要求,盐度低(4%),“亚硝峰”出现得早,峰值小;盐度高(12%),“亚硝峰”出现得晚且峰值大.%Taking cucumber as the raw material, this study determined the nitrate content and pH - value of the pickle which was preserved under different conditions. The results indicated that: in the earlier salting period, the content of nitrite in the pickle showed an increasing trend, it reached the highest value on the 3rd or the 4th day after salting, and then it decreased gradually. The content of nitrate in the pickle met the requirement of national standard after seven days' salting. It was found that lower salinity (4% ) led to the earlier emergence and smaller value of "nitrate content peak", and higher salinity (12% ) caused the later emergence and bigger value of "nitrate content peak".

  9. 不同培养条件下对阿萨希毛孢子菌生物被膜影响的研究%Research on biofilm formation of asahii trichosporon on different temperature and pH value

    Institute of Scientific and Technical Information of China (English)

    樊昕; 任晓萍; 李海涛; 杨蓉娅

    2011-01-01

    Ob jsctive To study the abilily of the form ation of T . asahii biofilm ( T . asahii BF ) in vitro on different ten perature and pH value .M ethods W ith T .asahii polystyrene surface form ation biofiln 48 h for evaluation siandard ,itwas observed different biofilm formation differences at 20℃ ,25℃ ,30℃ ,35 ℃ and40℃ .W ith T .asahii biofilm at30℃ for evaluation standard ,itw as observed different biofilm form ation differences at different pH valie .The activity of biofilm was measured and quantitative analyzed by XTT and absorbance .R esults It was observed that biofilm forming speed was more quick follow ing tem perature elevated during 30 -35℃ .But biofilm stabality was gradually reduce at more than 35-40℃ .Biofilm was not form ed at pH =5 .0 and pH=9 .0 .BF form-ing showed slowly non —lineargrowth .T . asahii biofilm began to m ature during 24-48 h,showed relative growth stagnation during 48 -56 h and decreased gradually after then . C onclusion D ifferent ten perature and pH value could affect signiScantly T . asahii biofilm fbm ation .The ability and extent to form biofilm of T . asahii was significantly enhanced at culture conditions that was 30-35℃ and pH =7.0.%目的 观察不同培养温度和pH培养基对阿萨希毛孢子菌(asahii trichosporon,T.asahii)生物被膜(biofilm,BF)形成的影响.方法 以T.asahii聚苯乙烯表面形成生物被膜48 h为评价标准,观察其在20℃, 25℃,30℃,35 ℃和40℃培养温度下观察T.asahii生物被膜的差异性;在30℃培养温度下应用不同pH培养基和采用XTT法测定生物膜活性并定量分析.结果 30℃-35℃下生物被膜形成能力最强,其随着温度不断升高,其生物被膜形成速度加快,但是40℃时稳定性逐渐降低;pH=5.0时和pH=9.0不能形成生物被膜;pH=7.0时生物被膜形成表现为缓慢的非线性生长,24-48 h生物被膜开始成熟,48 h-56 h间出现一相对的生长停滞期,此后逐渐下降.结论 不同培养温度和p

  10. 电磁场对结垢过程中电导率及pH值的影响%Influence of electromagnetic field on conductivity and pH value in fouling process

    Institute of Scientific and Technical Information of China (English)

    王建国; 何芳; 邸昊; 徐志明

    2013-01-01

    通过双路对比实验模拟现场换热设备结垢过程,基于水处理技术阻垢及缓蚀性能在线评价实验台的实验数据,利用多项式回归模型对变频电磁场作用下水质参数电导率、pH值的变化规律进行分析,结合Matlab和Origin处理软件基础性地研究磁场作用时间与多种水质参数的关系及影响程度,结果表明:水质参数电导率较pH值对电磁场参数的解释程度更高,电导率相比pH值对于建立电磁场参数与多水质参数之间的数学模型是更为重要的水质参数,得出了电磁场参数与电导率、pH值之间的数学模型,为建立多水质参数与电磁抑垢效果之间的数学模型提供了基础理论,并为探索电磁抑垢机理及应用提供了实验依据.%The fouling process of heat exchange equipment was simulated by the twin channel contrast experiment. Based on the experimental data of the water treatment technology and the fouling prevention and antii-corrosion effect of online evaluation experiment, the variation of conductivity and pH value under the influence of frequency conversion electromagnetic field was analyzed by using the polynomial regression model. The influence degree and relation between water quality parameters and magnetic acting time were fully analysed by using Matlab and Origin software. The results show that compared with pH value, the conductivity can better explain the electromagnetic field parameters and is more important for constructing the mathematical models of electromagnetic field parameters and multii-water quality parameters. The mathematical models of electromagnetic field parameters and conductivity, pH value were obtained, which provide the theoretical basis for the mathematical model of multi-water quality parameters and mitigation of fouling effect, and the experimental basis for the electromagnetic field anti-fouling mechanism and application.

  11. Physiological Response of Four Azalea Species to Water with Different pH Values%4个杜鹃品种对不同pH值灌溉水的生理响应

    Institute of Scientific and Technical Information of China (English)

    鲜小林; 陈睿; 秦帆; 万斌; 潘远智

    2013-01-01

    With four species of azalea as materials, we studied the growth and physiological indexes under pH 4. 5,5. 5,6. 5,7. 5,8. 5 irrigation water,in order to analysis the growth conditions with different acidity and alkalinity irrigation water. The results showed that; (1) With the pH increasing, the chlorophyll contents, superoxide dismutase activities, catalase activities and new shoot growth rates of four species increased firstly and then decreased, while the relative conductivities were contrary; (2) Under pH 5. 5, the chlorophyll contents of ' Mevrouw. A', ' Fugeer No. 1' and 'Green Glow', the CAT activities of 'Mevrouw. A'.'Spring Dance' and 'Green Glow' were maximum. The same to SOD activities and new shoot growth rates of the four species,while the chlorophyll content of 'Spring Dance' with pH 4. 5 treatment were maximum. The same to CAT activity of 'Fugeer No. 1'. Under pH 8. 5,all relative conductivities were maximum, while the other indexes were contrary; (3) With pH 4. 5~5. 5,the cultivation matrix which initial pH value was about 5. 0 could be maintained in the optimum pH range,about 5. 0. Therefore,azalea can grow well with the irrigation water of pH 4. 5 - 5. 5 in the Southwest, and 'Green Glow' even can grow with the untreated water of pH 7. 5. It is good for extension and breeding,also is a excellent resource for alkali tolerance rootstocks of azalea.%以4种杜鹃品种为材料,研究了pH 4.5、5.5、6.5、7.5(CK)、8.5的灌溉水对其生长发育和生理指标的影响,以分析杜鹃品种在不同酸碱性灌溉水浇灌下的生长情况,为杜鹃花品种的广泛推广提供核心种质资源和栽培管理奠定理论基础.结果表明:(1)4个杜鹃品种的叶绿素含量、SOD、CAT活性和新梢生长率总体上随灌溉水pH值的增加表现为先升高后降低的趋势,相对电导率变化则相反.(2)在pH5.5处理下,‘德国粉鹃’、‘富哥尔一号’和‘绿色光辉,的叶绿素含量最高,‘德国粉鹃’、

  12. 呼出气冷凝液pH值与迟发型VAP的相关分析%Relevance between pH value of exhaled breath condensate and late ventilator associated pneumonia

    Institute of Scientific and Technical Information of China (English)

    齐天杰; 阎锡新; 李帅; 李海涛

    2012-01-01

    OBJECTIVE To find out and master the relevance between pH value of exhaled breath condensate (EBC) and late ventilator associated pneumonia (VAP). METHODS A prospective study was conducted on 57 patients with late VAP hospitalized in ICU of Respiratory Department in the Second Hospital of Hebei Medical University from May 2009 to Apr. 2011. Meanwhile, 60 healthy cases were enrolled for control. The clinical data were collected to further calculate the pulmonary infection score (CPIS). In the same time, EBC of all patients were collected to measure pH value. Then the statistical analysis was carried out. RESULTS One hundred and seventy-three pathogenic bacteria were isolated from the secretion of EBC of the 57 patients, which mainly were Pseudo-monas aeruginosa and Acinetobacter baumannii, acounting for 24. 86% and 23. 70% , respectively. The pH value of EBC on diagnosis day of VAP declined obviously compaired with that on three days after tracheal intubation(t = 5. 802,P<0. 05)and that in healthy control group (t= 12. 146,P<0. 05). CONCLUSION The detection of pH value of EBC is helpful for the diagnosis of late VAP.%目的 探讨呼出气冷凝液pH值水平与迟发型呼吸机相关性肺炎发生及严重程度的相关性.方法 选取2009年5月-2011年4月在河北医科大学第二医院呼吸科ICU住院的迟发型呼吸机相关性肺炎患者57例及健康体检者60名;收集患者临床资料,计算临床肺部感染评分;并同步收集患者的呼出气冷凝液,测量pH值;之后行统计学分析.结果 57例迟发型VAP患者,有创机械通气期间下呼吸道分泌物共分离出病原菌173株,主要为铜绿假单胞菌及鲍氏不动杆菌,分别占24.86%及23.70%;迟发型VAP诊断当天呼出气冷凝液pH值较插管后第3天及健康对照组均有明显下降(t=5.802,P<0.05;t=12.146,P<0.05).结论 呼出气冷凝液pH值检测有助于迟发型VAP的诊治.

  13. NHE-1 miRNA转染所致细胞内pH值变化对BACE1的影响%Influence of reduced intracellular pH value by NHE-1 gene silence on BACE1

    Institute of Scientific and Technical Information of China (English)

    于国华; 方伯言

    2012-01-01

    Objective To transfect the adenovirus mediated NHE-1 miRNA into human neuroblastoma(SH-SY5Y), and investigate the expression of BACE1 with the condition of the change of intracellular pH value. Methods The human neuroblastoma (SH-SY5Y) cell were cultured, enrolled and randomly divided into 3 groups, named as normal control group, NHE-1 gene knock down group and negative control group, and structured the NHE-1 gene knock down model. The intracellular pH value was detected in each group by fluorescence spectrophotometer, cells were examined for mRNA and protein expression of BACE1 by Real-time PCR and Western blotting. Results Compared with control group, the intracel-lular pH value was significantly lower in NHE-1 gene knock down group by fluorescent probe method (P <0.01) , while it had no change in negative control group; furthermore, the BACE1 mRNA expression and protein level were significantly higher in NHE-1 gene knock down group than those in paired normal control group (P <0.01), the BACE1 mRNA expres-sion and protein level had no change in negative control group. Conclusions The lower intracellular pH value condition is responsible for the higher BACE1 expression.%目的 探讨腺病毒介导的人Na+-H+交换体-1(NHE-1) miRNA转染人源性神经母细胞瘤细胞株(SHSY5Y)后,细胞内pH值变化及其对β位淀粉样前体蛋白裂解酶1(BACE1)的影响.方法 培养SH-SY5Y,随机分为正常对照组、NHE-1基因敲低组和阴性对照组,并构建NHE-1基因敲低细胞模型.采用荧光分光光度计测定各组细胞内pH值,通过Real-time PCR及Western blotting检测BACE1 mRNA及蛋白表达.结果 与正常对照组相比,NHE-1基因敲低组细胞内pH值明显降低(P<0.01),阴性对照组细胞内pH值无明显变化;NHE-1基因敲低组细胞内BACE1 mRNA表达及蛋白含量明显增高(P<0.01),阴性对照组细胞内BACE1 mRNA表达及蛋白含量无明显变化.结论 细胞内pH值降低能够增强BACE1的表达.

  14. 酸奶在储藏过程中酸度、pH值、细菌的变化%CHANGES OF ACIDITY,PH VALUE AND BACTERIA COUNT OF YOGURT DURING STORAGE

    Institute of Scientific and Technical Information of China (English)

    杜磊; 张光杰

    2011-01-01

    In the paper, we measured the acidity, the pH value and the viable count of Lactobacillus of yogurt stored at different temperatures to determine optimal storage conditions and the peak drinking period of yogurt.Firstly, we respectively stored the yogurt samples of the same batch at the normal temperature, 4 ℃ and - 18 ℃ ; then, we observed the sensory changes and measured the pH value and the acidity at different time points; finally, we calculated the viable count by plate count method. The study showed that the amount of lactic acid bacteria in the yogurt stored at normal temperature for 5 days was up to 4.6 × 108 cfu/mL, the acidity 85.7 °T, and pH 4.08, and the yogurt had a small amount of milk serum separated out and had a good taste; the amount of lactic acid bacteria in the yogurt stored at 4 ℃ for 13 days was up to 4.6 × l08 cfu/mL,the acidity 85.5 °T, and pH 4.05, and the yogurt had a good taste ; and the amount of lactic acid bacteria in the yogurt stored at -18 ℃ for 19 days was up to4.5 ×108 cfu/mL, the acidity 85.5 °T, and pH 4.06, but the tissue structure changed. So, the yogurt stored at 4 ℃ for 13 days was in the peak drinking period.%将酸奶储藏在不同温度条件下,通过测得其酸度、pH值和乳酸茵活茵数,得出使酸奶的品质变化最小、货架期较长的最佳储藏条件和酸奶的最佳饮用期.先将同批酸奶分别置于常温、4℃和-18℃下,在储藏期不同时间点进行观察,测定其pH值、酸度,观察其感官变化.采用平板茵落计数法计算活茵数.研究表明,常温储藏5 d的酸奶茵含量最高达到4.6×10.cfh/mL,酸度为85.7°T,pH=4.08,有少量乳清析出,口感适宜;4℃储藏13 d的酸奶茵含量最高达到4.6×103 cfu/mL,酸度为85.5°T,pH=4.05,口感适宜;-18℃储藏19 d的酸奶菌含量最高达到4.5×108 cfu/mL,酸度为85.5°T,pH=4.06,但组织结构已发生改变.故4 ℃储藏的酸奶13 d内饮用最好.

  15. Analysis of the Changes in the Value of Oral pH in Patients with Oral Complications and the Corresponding Nursing%口腔并发症病人口腔pH值变化与护理分析

    Institute of Scientific and Technical Information of China (English)

    李静; 张楠

    2015-01-01

    目的:分析和研究护理干预对口腔并发症患者口腔pH值的影响。方法整群选取2012年6月-2014年8月内科住院口腔pH值异常患者84例,将其按投币随机法分为观察组与对照组,每组各有患者42例。对照组患者给予常规口腔护理干预;观察组患者在常规口腔护理基础上加用pH纠正液含漱,将两组患者护理干预2周后的口腔pH值变化情况及口腔并发症发生情况进行对比。结果两组患者护理干预前、后口腔pH值相比较院两组患者护理干预前口腔pH值差异无统计学意义,P>0.05;观察组患者护理干预后口腔pH值明显高于对照组,P0.05. After nursing intervention, the oral pH value was much higher in the observation group than that in the control group, P<0.05. The incidence of oral complications in the observation group was obviously lower than that in the control group, P<0.05. Conclusion The incidence of oral complications in critical patients in Department of Internal Medicine is closely related to the abnormal oral pH value. Conventional oral nursing combined with gargling pH correction fluid plays a key role in preventing the incidence of oral complications and reducing the suffering of the patients.

  16. 可见/近红外光谱结合遗传算法无损检测牛肉 pH 值%Nondestructive determination of pH value in beef using visible/near-infrared spectroscopy and genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    马世榜; 汤修映; 徐杨; 彭彦昆; 田潇瑜; 付姓

    2012-01-01

    In order to realize nondestructive and rapid determination of beef pH stored at 4℃ during its whole shelf-life, a laboratory visible/near-infrared spectroscopy system using visible/near-infrared spectroscopy and genetic algorithm was built to collect 120 beef samples' reflectance spectra in the 400-1700nm. These samples were stored at 4℃ for l-18days. The reflectance spectra of samples were performed with different pretreatments, such as multiplicative scatter correction (MSC), Savitzky-Golay(SG) smoothing method. The prediction model of multiple linear regression (MLR), partial least squares regression(PLSR) and least square-support vector machine(LS-SVM) were constructed for prediction of pH value in beef with full-spectrum and effective wavelengths selected by genetic algorithm(GA), respectively. The results showed that the MSC combined with SG smoothing was the best pretreatment, and the performance of models established with effective wavelengths selected by GA were better than the full-spectrum models, and the best performance was achieved by LS-SVM model, its correlation coefficient and standard deviation were 0.935 and 0.111, respectively. The prediction accuracy was improved. This study demonstrated that the LS-SVM model built by using visible/near- infrared spectroscopy with GA could nondestructively and rapidly determine pH value in beef during its whole shelf-life. This research provides a basis of further developing device for nondestructive and rapid determine pH value in beef.%为了实现牛肉在整个货架期内(4℃环境)pH值的无损快速检测,该文采用可见/近红外光谱技术并结合遗传算法(GA,genetic algorithm),搭建了可见/近红外光谱检测系统,采集储藏在4℃下1~18d的120个牛肉样品400~1 700 nm范围的光谱,用不同预处理方法处理,并分别建立全波段光谱和经过遗传算法提取有效光谱的预测牛肉pH值的多元线性回归( MLR,multiple linear regression)模型

  17. 透析液pH值和电导率测量仪的设计与试验%Design and experiment on the dialysate pH value and electrical conductivity measuring instrument

    Institute of Scientific and Technical Information of China (English)

    刘致滨; 宋文晓; 杨晶娟; 朱懿恒; 卢广文

    2012-01-01

    背景:在血液透析过程中,透析液的浓度直接决定了透析的效果.目的:旨在设计一种应用于测量透析液浓度的pH值和电导率的装置,并通过试验对测量仪的性能进行测试和分析.方法:开发用于测量透析液的pH值和电导率测量仪,提出一种频率可调的双极性间歇脉冲激励方法应用于电导率测量,极大地减少极化效应和电容效应对测量的影响,同时对电导率测量值进行温度校正.采用两点校正法对pH值进行标定,提高测量的精确度.结果与结论:测量仪样机在实际的透析液中进行相关试验.测量仪的pH值测量值和标准值的相对误差小于1%,电导率的测量值与标准值的相对误差小于0.5%.通过对比试验说明,可调频率的间歇双极性脉冲法比双极性脉冲法的误差小,能及时地跟踪透析液浓度的变化.结果表明,测量仪能够实现对透析液浓度的精确测量,满足血液透析机对透析液的实时检测要求,可以广泛应用于血液透析机中透析液的浓度检测中.%BACKGROUND: The dialysate concentration directly determines the efficacy of dialysis during the process of hemodialysis. OBJECTIVE: To design a measuring instrument of dialysate pH value and electrical conductivity and to test the performance of the measuring instrument through experiments.METHODS: The variable frequency of bipolar interim pulse method was put forward to reduce polarization and capacitance effect on the conductivity measurement tremendously while simultaneously temperature compensation was selected for electrical conductivity. Two-point correction method was used for calibration test to improve the accuracy measurement of pH value. RESULTS AND CONCLUSION: The trial manufactured carried experiment on the actual dialysate. The relative error between the calibration result and the accurate value for dialysate pH value was less than 1 % and that of electrical conductivity was less than 0.5%. Besides

  18. Effect of benflumetol on DNA content and pH value of the lysosome of Plasmodium berghei%本芴醇对疟原虫DNA含量及溶酶体pH值的影响

    Institute of Scientific and Technical Information of China (English)

    苏瑞斌; 时云林; 李国福; 赵京花

    2001-01-01

    Objective:To study the antimalarial mechanism of benflumetol (B). Methods: Flow cytometry (FCM) was used to analyze the effects of B and chloroquine (CQ) on DNA content of Plasmodium berghei and pH value of the lysosome of malarial parasites. Results: DNA content of the plasmodia not treated with any drugs was not changed in 24 hours,while benflumetol could decrease the DNA content: the DNA content began to decrease 2 h after the drug administration and reached the minimum by 16 h, but somewhat increased at 24 h after administration. The pH in the lysosome increased 1 h and restored premedication level 4 h after benflumetol administration. Chloroquine had the same effects on DNA and lysosome pH of malarial parasites.Conclusions: The antimalarial mechanism of benflumetol is directly related to its effect to inhibit the synthesis of DNA.%目的:探讨本芴醇的抗疟作用机制。方法:采用流式细胞术(FCM)分析了本芴醇和氯喹对鼠伯氏疟原虫K173株DNA含量及溶酶体pH值的影响。结果:对照组疟原虫DNA含量在各时间点没有显著变化。本芴醇单次给药后,随时间推移疟原虫DNA含量逐渐减少,药后2 h两给药组疟原虫红内期 DNA含量开始降低,到16 h降到最低,但药后24 h DNA含量又有所回升。本芴醇单次给药后1 h起疟原虫溶酶体pH值开始升高,药后3 h升至最高,药后4 h原虫溶酶体pH值恢复至药前水平。对照药氯喹对疟原虫DNA含量和溶酶体pH值也有相同影响。结论:本芴醇的抗疟作用与其抑制DNA合成相关,但与其升高溶酶体pH值的关系不明确。

  19. Study on the Optimun pH Value in the Addition of Alkali in Laojiao Dough%老酵面团对碱工艺最佳p H值的研究

    Institute of Scientific and Technical Information of China (English)

    毛羽扬; 朱在勤; 纪有华; 张文涛; 徐传骏

    2001-01-01

    Food made with dugh fermented with Laojiao naturally fermented dough tastes good and enjoyes perfect flavour. Organic acid was produced during fermentation and this acid should be neutralized by adding alkali.How much alkali should be added to achiveve the optimum flavour and taste has always been one of the difficult points in refreshment production technology. This study proved that the refreshments made of naturally fermented dough laojjao right after the addition of alkali and with the pH vlue between 6.15 ~6.20 could achieve good flavour. And the refreshments made of th laoj iao after the addition of alkali to be kept about 25 minutes in which the pH value could reach 6. 1 2 ~6.15,could gain even better flavour.%用老酵来发酵的面团其制品口感好,风味好。由于发酵过程产生有机酸需对碱中和,如何控制对碱量,达到最佳风味效果,历来为面点工艺上的一个难点。研究证明,发酵面团对碱后立即制作,其面团的pH值在6.15~6.20区域内,制成品的效果很好。发酵面团对碱再醒发25min后,其面团的pH值在6.12~6.15区域内,这时制成品的效果更好。

  20. pH值调控对秸秆两阶段厌氧发酵产沼气的影响%Effect of pH Values Control on Biogas Production of Agricultural Straw with Two-phase Anaerobic Fermentation

    Institute of Scientific and Technical Information of China (English)

    陈广银; 曹杰; 叶小梅; 杜静; 常志州

    2015-01-01

    , and methanogenesis. Large literature search showed that hydrolysis and acidification is the limiting step of biogas production of biosolid wastes. How to improve the hydrolysis and acidification rate of biosolid wastes? Much work has been done, including pretreatment, co-digestion, high efficient microbial inoculants, fermentation process control, et al. PH value is an important factor to hydrolysis and acidification of biosolid wastes. Much work has been done on characteristics of hydrolysis and acidification of biosolid wastes in acidic environment, but there was little information on characteristics of hydrolysis and acidification of biosolid wastes in alkaline environment. In order to evaluate the effect of alkaline environment control on hydrolysis and acidification and subsequent biogas production of agricultural straw, changes of daily biogas yield, methane content, pH value, COD content of hydrolysis and acidogenic phase and characteristics of biogas production of methanogenic phase were studied. The results showed that two-phase anaerobic fermentation of agricultural straw could be operated normally and TS biogas yield and average methane content were 281.28mL/g TSadded and 47.36%, respectively. Cumulative biogas yield of hydrolysis and acidogenic phase, average methane content and cumulative methane yield of treatment of adjusting pH value of hydrolysate to 8.0 daily was improved by 24.51%. 2.5 percent and 29.39%. Adjusting pH value of hydrolysate to 9.5 and 11.0 daily could inhibit biogas production of hydrolysis and acidogenic phase and increase COD content of hydrolysate, but it was bad for biogas production of hydrolysate and cumulative biogas yield of methanogenic phase were only 89.97% and 17.48% to that of CK. Maintaining hydrolysis and acidogenic phase in alkaline environment was beneficial for dissolving out of hemicellulose and lignin but bad to cellulose.

  1. Lixiviação do ametryn em Argissolo Vermelho-Amarelo e Latossolo Vermelho-Amarelo, com diferentes valores de pH Ametryn leaching on Red-Yellow Latosol and Red-Yellow Ultisol with different pH values

    Directory of Open Access Journals (Sweden)

    S.R.B. Andrade

    2010-01-01

    Full Text Available Objetivou-se com este trabalho avaliar o potencial de lixiviação do ametryn num Argissolo Vermelho-Amarelo e num Latossolo Vermelho-Amarelo utilizados com pastagens no Brasil, com diferentes valores de pH. Para isso, foram avaliados 120 tratamentos (quatro solos associados a três intensidades de chuva e 10 profundidades, em parcela subdividida no delineamento inteiramente casualizado, com três repetições. Colunas de PVC de 50 cm de comprimento por 10 cm de diâmetro foram preenchidas com os solos e umedecidas; em seguida, aplicou-se o herbicida e simularam-se chuvas no topo delas, nas intensidades especificadas de acordo com o tratamento. Após 72 horas, todas as colunas foram dispostas na posição horizontal e abertas longitudinalmente, coletando-se amostras dos solos a cada intervalo de 5 cm de profundidade, para posterior extração e quantificação do herbicida e análise por cromatografia líquida de alta eficiência - CLAE. Posteriormente, no restante das amostras de solo, semeou-se ao longo de cada coluna a espécie indicadora Cucumis sativus. Concluiu-se que solos com baixo teor de matéria orgânica e/ou pH mais elevado apresentaram maiores índices de lixiviação do ametryn. Além disso, o método do bioensaio foi mais eficiente na confirmação da lixiviação do ametryn em comparação à CLAE.The objective of this work was to evaluate ametryn leaching potential in soil used for pasture in Brazil (Red-Yellow Latosol (LVA and Red-Yellow Ultisol (PVA with different pH values. Thus, 120 treatments were evaluated (four soils related to three rainfall intensities and 10 soil column depths. The experiments were arranged in a completely randomized design in split-plots and three replications. PVC columns of 10 cm diameter by 50 cm length were filled with the soil samples, moistened and placed upright for 48 hours to drain the excess water. The herbicide was applied and rainfall was simulated on top of the columns at intensities

  2. Ph3CCOOSnPh3.Ph3PO AND Ph3CCOOSnPh3.Ph3AsO: SYNTHESIS AND INFRARED STUDY

    Directory of Open Access Journals (Sweden)

    ABDOU MBAYE

    2014-08-01

    Full Text Available The mixture of ethanolic solutions of Ph3CCOOSnPh3 and Ph3PO or Ph3AsO gives Ph3CCOOSnPh3.Ph3PO and Ph3CCOOSnPh3.Ph3AsO adducts which have been characterized by infrared spectroscopy. A discrete structure is suggested for both, the environment around the tin centre being trigonal bipyramidal, the triphenylacetate anion behaving as a mondentate ligand.

  3. Effect of biochar on mineral nitrogen content in soils with different pH values%生物质炭对不同pH值土壤矿质氮含量的影响

    Institute of Scientific and Technical Information of China (English)

    罗煜; 赵小蓉; 李贵桐; 赵立欣; 孟海波; 林启美

    2014-01-01

    concentration. The causes for high fertility of these soils are multiple, but the source of the large amounts of organic matter and their high nutrient retention has been attributed to the extraordinarily high proportions of black carbon. Besides, the high available nitrogen (N) is from both direct nutrient addition by the biochar and greater nutrient retention. It is also reported biochar can influence soil N concentrations via affecting soil process, such as N transformation. However, it remains largely unknown how biochar affect N transformations.In this study, biochars were produced at 350°C (BC350) and 700°C (BC700) by using Miscanthus giganteus, and applied with and without ryegrass into soils with low (pH=3.8) and high pH values (pH=7.6) incubated for 180 days. Our results showed that the addition of biochar to soils had an average increase of total N content of 22% and 17%, respectively in acid and alkaline soils. Biochars had obvious effect on NH4+-N in acid soil. After 87 days of incubation, NH4+-N was declined to very low concentration. BC350 had a slight increase of NO3--N in acid soil. Compared with BC350, soils with BC700 significantly (p0.05) was observed in treatments with and without ryegrass, neither between day 87 and 180, suggesting mineralization was largely occurred at the early incubation time in the soil with biochar added. The effects of biochar on the form and content of soil mineral nitrogen were closely related to the biochar’s abilities including ammonium adsorption, enhancing soil pH value, enhancing ammonia volatilization, and microbial biomass nitrogen formation. In the practical application, using biochar as coating materials in producing the slow-release fertilizer to improve nitrogen use efficiency seems to be very promised, and more research is needed in this area in the near future.

  4. Processes and equipments for energy saving and emission reduction in dyeing plants (XV)——Control of pH value%印染厂节能减排实用工艺装备技术(十五)——染色pH值的控制

    Institute of Scientific and Technical Information of China (English)

    陈立秋

    2012-01-01

    以染浴pH值对牛仔服水洗、两相法印花后快速蒸化和活性染料浸染效果的影响等方面为实例,阐述染整加工中pH值测控的重要性;分析了pH值在线检测及控制系统的组成和系统控制器与外围设施的关系.%Taking the influence of pH value on denim washing, rapid ageing after two-phase printing and reactive dip dyeing for examples, the importance of pH value control in textiles wet processing is expounded. The composition of on-line detection and controlling system of pH value, as well as the relationship between control system and peripheral equipments are analyzed.

  5. Influence of pH value on the evolution and the crystal structure of manganese sulfate skeleton%pH控制硫酸锰骨架的演化及其晶体结构

    Institute of Scientific and Technical Information of China (English)

    王璐; 孙丽; 宋江锋; 周瑞莎

    2015-01-01

    在DMF/H2 O/CH3 OH的混合体系中,反应温度为170℃,MnSO4·4H2 O盐溶液在pH=5和7的条件下,加热72小时,最终得到了结构不同的硫酸锰骨架[Mn2(SO4)3]·(H3O)2(1)和[Mn3(SO4)2(OH)2(H2O)2](2)。化合物结构通过单晶X-射线和红外光谱所表征,相应的晶胞参数:化合物1,立方晶系,空间群:P213,a=10.2009(12)Å,V=1061.49(37)Å3,GooF=1.158,Flack parameter 0.02(2),R1=0.0186(I>2sigma);化合物2,四方晶系,空间群:Pbcm,a=7.3214(15)Å,b=9.984(2)Å,c=13.291(3)Å,V=971.5(4)Å3,GooF=1.063, R1=0.0227(I>2sigma);单晶X射线分析显示化合物1是一个三维单手性硫酸锰骨架,化合物2是一个非手性羟基硫酸锰骨架。实验结果说明,pH值对硫酸锰骨架的改变起重要作用。%Under the mixed DMF/H2 O/CH3 OH,the MnSO4·4H2 O solution was heated for 72 hours at 170℃ at pH values 5 and 7, respectively,two manganese sulfate skeleton,[Mn2(SO4)3]·(H3O)2(1) and[Mn3(SO4)2(OH)2(H2O)2] (2) were ob-tained. Compounds 1 and 2 are characterized through single crystal X-ray diffraction and infrared spectrum. The corresponding cell parameters for compound 1,cubic crystal system,space group P213,a=10. 2009(12)Å,V=1061. 49(37)Å3,GooF=1. 158,Flack parameter 0. 02(2),R1=0. 0186(I>2sigma);for compound 2,tetragonal crystal system,space group Pbcm,a=7. 3214(15)Å,b=9. 984(2)Å,c=13. 291(3)Å,V=971. 5(4)Å3,GooF=1. 063,R1=0. 0227(I>2sigma). Single crystal X ray analysis showed that compound 1 is a 3D single chiral manganese sulfate skeleton however, compound 2 is a hydroxy manganese sulfate skele-ton. Experimental results show that pH value plays an important role in the evolution of manganese sulfate skeleton.

  6. The Regulation of pH Value of Liquid Feed on Blood Gas Parameters in Holstein Bull Calves%液体饲料pH值对荷斯坦公犊血气指标的调控

    Institute of Scientific and Technical Information of China (English)

    屠焰; 邱国梁; 周怿; 云强; 齐东; 王家杰; 刁其玉

    2014-01-01

    0.8126、0.8298。血液pH值和pCO2随日龄变化有显著改变(P<0.05);除HCO3-、ABE、SBE外,其他血气指标符合正态分布规律(P>0.05)。代乳品中植物蛋白占总蛋白的比例由50%提高到80%时,犊牛平均日增重和干物质采食量降低,但血气指标并未受到影响(P>0.05)。【结论】随代乳品乳液pH值的降低,21-63 d犊牛血液HCO3-、ABE、TCO2、SBC、SBE显著降低,可作为评价日粮酸度效果的敏感指标。%Objective] Due to the immature gastrointestinal function and low ability digest dietary, diarrhea or other nutritional diseases were easy to arise in suckling calves that bring about low survival rate. Compared with adult cattle, liquid milk replacer is the main feed for the early weaned calves. Thus, acidity of milk replacer emulsions has more important effect on calf health. But the change regulation, the normal value scope of blood gas parameters in calves are not in any systematic manner, so that it is unable to determine whether the appropriate dietary acidity is. To study the change regulations of blood gas parameter in calves, an experiment was carried out to investigate the variations of blood gas parameters in calves which fed liquid feed with different pH.[Method]The pH values of a milk replacer (6.2, 5.5, 5.0 or 4.5) and the ratio of vegetable protein to total protein in the milk replacer (50% or 80%) were used to form an 2 × 4 factorial design in this experiment. Forty-eight neonatal healthy Chinese Holstein male calves were allotted into eight groups and each group was fed with one of the 8 milk replacer emulsions. The experiment lasted 63 d with 21 d for adaptation and 42 d for test. Growth performance was determined fortnightly, the intake of milk replacers and pellet diet were recorded every day. Blood samples were collected on 21 d and 49 d. The pH value, partial pressure of carbon dioxide (pCO2), partial pressure of oxygen (pO2), oxygen saturation (SO2

  7. Effects of Different Raw Material Proportions and Moistening Levels on pH Value and Enzyme Activity during Koj i-making Process%制曲过程中不同原料配比、润水量对成曲pH 值、酶活的影响研究

    Institute of Scientific and Technical Information of China (English)

    陈振伟

    2014-01-01

    Analyze the effects of different raw material proportions and moistening levels on pH value and enzyme activity during koji-making process,set six groups of different raw material proportions and moistening levels using the same kind of koj i under the same conditions.The result reflects that the effect of infeed-koji water content on finished koji pH value is greater than that of raw material proportion on pH value;while water has greater effect on finished koji enzyme activity than raw material proportion.%通过使用同一种曲,设定六组不同原料配比、润水量,在同一条件下进行制曲,研究了制曲过程中不同原料配比、润水量对成曲 pH 值、酶活的影响。结果表明:入曲水分对成曲 pH 的影响比原料配比对pH 的影响要大;成曲酶活受水分的影响比受原料配比的影响大。

  8. Design and Application of Online Determination and Control System of pH Value for Spherical Ni(OH)2 PreParation%球形Ni(OH)2制备中pH在线检测及控制系统的设计和应用

    Institute of Scientific and Technical Information of China (English)

    李涛; 陈飞彪; 郭荣贵; 傅钟臻; 于丽敏; 夏雯; 蒋文全

    2011-01-01

    During the preparation of the spherical Ni(OH)2, pH meter may be influenced by some environmental factors, such as high salinity, high alkalinity, high temperature and strong convection. The stability and lifetime of pH meter would be shortened, and the determination and control of pH parameter are difficult. So a set of the online determination and control system of pH value are designed. The method determining the relative pH value outside of the reactor is introduced and the online determination device of pH value is designed. It implements the narrow-range fluctuation from 0. 02 to 0. OS Of pH valve. Meanwhile the control system based on configuration software and programmable logic controller ( PLC) is designed and there is a good result in real-time.%在球形Ni(OH)2制备过程中高盐度、高碱度、高温和强对流的环境因素导致pH电极稳定性降低,寿命缩短,pH参数检测和控制困难,为此采用反应釜外检测相对pH值的方法,设计pH在线检测装置和基于组态软件和可编程控制器的pH值在线控制系统,实现了pH值在0.02~0.05的微小波动范围测量,现场控制效果良好.

  9. Urinary pH and renal lithiasis.

    Science.gov (United States)

    Grases, F; Costa-Bauzá, A; Gomila, I; Ramis, M; García-Raja, A; Prieto, R M

    2012-02-01

    Formation of calcium oxalate crystals, either as monohydrate or dihydrate, is apparently unrelated to urinary pH because the solubilities of these salts are practically unaltered at physiologic urinary pH values. However, a urinary pH 6.0 may induce uric acid or calcium phosphate crystals formation, respectively, which under appropriate conditions may induce the development of the calcium oxalate calculi. We assessed the relationship between the urinary pH and the formation of different types of calculi. A retrospective study in 1,478 patients was done. We determined the composition, macrostructure, and microstructure of the calculi and the urinary pH, 50.9% of calcium oxalate monohydrate unattached calculi were present in patients with urinary pH 6.0, respectively. Infectious calculi were found primarily in patients with urinary pH >6.0 (50.7%). Only calcium oxalate monohydrate papillary calculi were associated with urinary pH between 5.5 and 6.0 (43.1%). Urine of pH 6.0 has an increased capacity to develop calcium phosphate crystals, which can act as a heterogeneous nuclei of calcium oxalate crystals. Oxalate monohydrate papillary calculi were associated to pH between 5.5 and 6.0 because the injured papilla acts as a heterogeneous nucleant. Consequently, measurement of urinary pH may be used to evaluate the lithogen risk of given urine.

  10. pH值及盐度对副溶血弧菌与霍乱弧菌生长影响的研究%Effects of pH value and salinity on growth of Vibrio parahaemol yticus and Vibrio cholerae

    Institute of Scientific and Technical Information of China (English)

    胡兴娟; 沈飚; 张文斌

    2011-01-01

    OBJECTIVE To study the effect of different pH value and salinity of broth on the growth of Vibrio parahaemolyticus and Vibrio cholerae, and to find out the best pH value and salinity. METHODS The bacterial .counts of Vibrio cholerae and Vibrio paraheamolyticus were detected referring to international and domestic request under differrent pH ralue and salinity concerntration. RESULTS The enrichment broth pH 7. 2 and salinity 3. 2% were the most suitable condition for the growth of V. Parahaemolyticus, pH 7. 1 and salinity 1. 2% were the most suitable condition to the growth of V. Cholera. CONCLUSION pH value and salinity of enrichment broth can influence the growth of V. Parahaemolyticus and V. Cholerae.%目的 研究增菌液pH值及盐度对副溶血弧菌和霍乱弧菌生长的影响,找出副溶血弧菌与霍乱弧菌的最佳生长pH和盐度.方法 应用阳性菌株副溶血弧菌和霍乱弧菌,参照国际和国内增菌液的要求,控制增菌液pH值和盐度条件,采用弧菌显色培养基检测副溶血弧菌和霍乱弧菌生长数.结果 增菌液pH值7.2、盐度3.2%时最适副溶血弧菌生长,增菌液pH值7.1、盐度1.2%时最适霍乱弧菌生长.结论 增菌液pH值和盐度对副溶血弧菌和霍乱弧菌生长有一定影响.

  11. Effect of initial pH value in aqueous solution on direct reaction kinetics of 2,4-D with ozone%溶液初始pH值对2,4-D臭氧直接反应动力学的影响

    Institute of Scientific and Technical Information of China (English)

    陈岚; 权宇珩

    2011-01-01

    @@ 引言 目前,农药被大量研制及施用,由此带来的农药污染越来越受到人们的重视.含氯苯氧梭酸类除草剂2,4-D(2,4-二氯苯氧乙酸)是一种使用较广、应用较早的除草剂.2,4-D自然降解较慢,由于具有非挥发性和可溶性,易导致地下水或地表水污染,水体中已经可以检测到2,4-D的存在.%In order to understand the kinetics of direct oxidation between ozone molecule and 2, 4dichlorophenoxyacetic acid (2,4-D), the ozone oxidation of 2,4-D using sufficient tert-butyl alcohol as free radical inhibiting agent was studied in a bubbling reactor. The effect of initial pH on 2,4-D direct oxidation process was discussed. The results show that direct oxidation of 2,4-D and transfer of O3 are affected hy initial pH. When the value of initial pH is lower than 3.3, the solution pH value maintains approximately constant during the process. When it is larger than 3. 3, the solution pH value drops abruptly and reaches a steady value in a short period, while concentration of ozone increases rapidly and does a steady concentration. With the increasing of initial pH the steady ozone concentration and pseudo-first-order rate constant increase, and the time required to reach this steady value decreases. Hatta numbers are lower than 0.03 for different pH values. The 2, 4-D degradation process by ozone molecule follows the slow rate kinetics. It shows that the direct reaction of 2,4-D and ozone molecule is a control step of whole kinetics process.

  12. Transcriptional control of the F0F1-ATP synthase operon of Corynebacterium glutamicum: SigmaH factor binds to its promoter and regulates its expression at different pH values.

    Science.gov (United States)

    Barriuso-Iglesias, Mónica; Barreiro, Carlos; Sola-Landa, Alberto; Martín, Juan F

    2013-03-01

    Corynebacterium glutamicum used in the amino acid fermentation industries is an alkaliphilic microorganism. Its F(0)F(1)-ATPase operon (atpBEFHAGDC) is expressed optimally at pH 9.0 forming a polycistronic (7.5 kb) and a monocistronic (1.2 kb) transcripts both starting upstream of the atpB gene. Expression of this operon is controlled by the SigmaH factor. The sigmaH gene (sigH) was cloned and shown to be co-transcribed with a small gene, cg0877, encoding a putative anti-sigma factor. A mutant deleted in the sigH gene expressed the atpBEFHAGDC operon optimally at pH 7.0 at difference of the wild-type strain (optimal expression at pH 9.0). These results suggested that the SigmaH factor is involved in pH control of expression of the F(0) F(1) ATPase operon. The SigmaH protein was expressed in Escherichia coli fused to the GST (glutathione-S-transferase) and purified to homogeneity by affinity chromatography on a GSTrap HP column. The fused protein was identified by immunodetection with anti-GST antibodies. DNA-binding studies by electrophoretic mobility shift assays showed that the SigH protein binds to a region of the atpB promoter containing the sigmaH recognition sequence (-35)TTGGAT…18nt…GTTA(-10). SigmaH plays an important role in the cascade of control of pH stress in Corynebacterium.

  13. Research on pH value and salinity of multipathogen enrichment broth for simultaneous growth of V.parahaemolyticus and V.cholera%副溶血弧菌和霍乱弧菌合检增菌液pH值和盐度的研究

    Institute of Scientific and Technical Information of China (English)

    沈飚; 胡兴娟; 汪云泉; 张文斌

    2011-01-01

    目的:研究共同增菌液pH值和盐度对副溶血弧菌和霍乱弧菌生长的影响,找出副溶血弧菌和霍乱弧菌共增菌液的最佳pH值和盐度.方法:利用副溶血性弧菌、霍乱弧菌以及杂菌对共同增菌液的pH值和盐度进行实验,通过弧菌显色平板计数验证增菌效果,从而确定两种弧菌的共同增菌液pH和盐度.结果:副溶血性弧菌和霍乱弧菌合检增菌液的最佳条件为pH8.4,盐度2.1%.结论:增菌液pH值和盐度的改变对副溶血性弧菌和霍乱弧菌生长具有一定影响.%Objective:To study the effect of different pH values and salinities of multipathogen enrichment broth on the growth of V. Parahaemolyticus and V. Cholera, and to find out the best pH value and salinity. Methods: V. Parahaemolyticus, V. Cholera and other bacteria were applied to determine the pH value and salinity, and the enrichment effect was evaluated by Vibrio chromogenic medium. Results: The enrichment broth with pH 8.4 and salinity 2.1% are the most suitable condition to V.parahaemolyticus and V. Cholera. Conclusion: pH value and salinity of enrichment broth can influence the growth of V. Parahaemolyticus and V. Cholera.

  14. 慢性阻塞性肺病患者呼出气冷凝液pH值的变化%Changes of pH Value of Exhaled Breath Condensate in Patients with Chronic Obstructive Pulmonary Disease

    Institute of Scientific and Technical Information of China (English)

    李晓尘; 何静雅; 胡克

    2011-01-01

    目的:探索慢性阻塞性肺病(COPD)患者呼出气冷凝液(EBC)pH的变化和EBC中CO2对pH的影响.方法:分别对20例C()PD患者和健康志愿者用自制EBC收集器收集EBC,将收集的EBC两等份,一份立即测pH值,另一份通氩气后再测pH.结果:①通氩气前后,COPD组pH均低于健康组,通氩气前两组pH分别为(6.72±0.31)、(7.62±0.23),通氩气后为(7.66±0.17)、(8.54±0.19).②通氩气后,COPD组和对照组pH均显著升高,变异率均较通氩气前小.两组pH变化值与通氩气前pH值均呈负相关(r分别为-0.946,-0.807).结论:COPD患者EBC pH明显降低.EBC中CO2可以降低EBC pH,为排除CO2对pH的影响,检测EBC pH前需预先除去EBC中的CO2.%Objective: To explore the change of exhaled breath condensate (EBC) pH of patient with chronic obstructive pulmonary disease (COPD) and the impact of CO2 on EBC pH.Methods: Twenty healthy subjects and 20 COPD patients were enrolled in this study.EBC was collected with self-made EBC collection device.Each EBC sample was divided into two aliquots.The pH of one aliquot was measured immediately, and the other was measured after bubbled with argon.Results: Before and after argon treatment respectively, the pH of COPD was lower than that of the healthy (6.72±0.31 vs 7.62±0.23, and 7.66±0.17 vs 8.54±0.19, respectively).There was a significant increase of pH in deaerated aliquot and a correlation between pre-argon and subsequent changeof pH in both COPD and healthy group (r= -0.946 and -0.807 respectively).Conclusion: There is a significant reduction of EBC pH in COPD.CO2 could decrease the pH of EBC.In order to exclude the impact of CO2 on EBC pH, deaeration is needed before the measurement of pH.

  15. Isolation and survival of Yersinia enterocolitica in ice cream at different pH values, stored at -18°c Isolamento e sobrevivência de Yersinia enterocolitica em sorvetes de distintos pH, armazenados a -18°C

    Directory of Open Access Journals (Sweden)

    Norma B. Barbini de Pederiva

    2000-09-01

    Full Text Available The presence of Yersinia enterocolitica was investigated in 203 samples of industrial (123 and non-industrial ice cream (80. Two Y. enterocolitica strains were isolated from non-industrial ice cream, which suggests the possibility of post-manufacturing contamination. One strain was typed as B:1A, O: 3,50,51; lis Xz, while the other one was biotyped as: B:1A but not serologically typed. Survival of Y. enterocolitica was investigated by inoculating nine samples of industrially manufactured ice cream to contain 20 CFU/ml of Y. enterocolitica and stored at -18°C for 480 days. The inoculated samples were classified into three different groups according to their pH (Group 1: pH 4-5; Group 2: pH 5-6 and Group 3: pH 6-7. Viability was determined by a combination of direct plating and enrichment. In Group 1, Y. enterocolitica was not detected after 150 days of storage, while in Groups 2 and 3, this microorganism was isolated until day 480 of storage. These findings suggest that the survival time of Y. enterocolitica in ice cream stored at -18°C is significantly (p Neste estudo pesquisou-se a presença de Yersinia enterocolitica em 203 amostras de sorvetes, sendo 123 de fabricação industrial e 80 de fabricação artesanal. Isolaram-se 2 cepas a partir de sorvetes artesanais, uma das quais foi caracterizada como B:1A, O:3,50, 51; lis Xz e a outra se tipificou como Y. enterocolitica B:1A mas não se tipificou sorologicamente, o que sugere uma contaminação pós processo. Em 9 dos sorvetes de fabricação industrial de distintos pH, estudou-se a sobrevivência desse microrganismo, inoculando-os com 20 UFC/ml de Y. enterocolitica, quando armazenados durante 480 dias a -18°C. Esses sorvetes, segundo seu pH, agruparam-se em: Grupo 1: pH: 4-5, Grupo 2: pH 5-6 e Grupo 3: pH: 6-7. Determinou-se a viabilidade pelas curvas de morte usando semeadura direta e enriquecimento. Nos sorvetes do grupo 1, Y. enterocolitica só foi detectada até o 150° dia de

  16. Effect of Clay with Different pH Values on Organophosphorus Pervasion%不同pH值黏土层对有机磷渗透的影响分析

    Institute of Scientific and Technical Information of China (English)

    宋顶峰; 李红艳; 李绪谦; 周记玲

    2011-01-01

    采用施压条件下有机磷溶液渗透通过粘性土层的实验,模拟有机磷越流通过弱透水层的过程,研究粘土层pH值不同时对有机磷渗透迁移的影响规律.分析认为,有机磷渗透通过粘性土层的能力随着土层pH值的升高而降低;pH为7.5时矿化率为98.75%,迁移率为1.25%,土层pH值≥8.5时有机磷未穿透粘土层,阻滞效果明显.矿化形成的PO4离子占总磷的百分比随着土层pH值的升高而增加,与Ca+离子结合形成沉淀物的能力增强,粘土pH值的升高对有机磷的降解转化具有明显的促进作用.%Organophosphor was put on pressure to permeate the cohesive soil in this experiment, for simulating the process of organophosphor leakage permeating the aquitard, in order to explore the influence of clayey pH on pervasion and migration of organophosphorus. The findings show that pervasive ability of organophosphorus fall with the rise of clayey pH, mineralization rate is 98.75% and migrating rate is 1.25% when pH is 7.5. Organophosphorus can not permeate the clay when pH ≥8.5 and retardation of clay on organophosphor is obvious. The proportion of PO43- contributing to TP will raise with pH of clay, and the ability of forming precipitate with Ca2+ enhance also. The rise of clayey pH has the obvious advance on the degradation and conversion of organophosphorus.

  17. Influence of pH value and slow granule on HA/TiO2 coatings deposited by hydrothermal-electrochemical method%pH 值和缓冲剂对水热电化学沉积 HA/TiO 2涂层的影响

    Institute of Scientific and Technical Information of China (English)

    马凤仓; 徐敏; 刘平; 李伟; 刘新宽; 何代华; 陆晓琴

    2014-01-01

    Using titanium alloy after micro-arc oxidation as substrate,HA/TiO 2 coatings were prepared by hy-drothermal-electrochemical method.The morphologies and phase compositions of coatings were characterized by means of SEM and XRD,and the variation of pH value of electrode/electrolyte was measured by means of pH microprobe;in this way,the influences of pH value and slow granule on HA/TiO 2 coatings deposited by hydro-thermal-electrochemical method were investigated.The results show that micro-arc oxidation coatings contrib-ute to HA deposited by hydrothermal-electrochemical method and HA crystals are well-distributed and densified in the coatings.When the pH value was within the range of 2 to 8,the increasing of the pH value contributes to HA crystals with high crystallinity and the growth of HA along the crystallographic plane (002).During the process of depositing HA by hydrothermal-electrochemical method ,pH value on the surface of electrode increa-ses at first and then decreases with the deposition time,while pH value of electrolyte decreases with the deposi-tion time.pH value and slow granule have obvious influences on the morphologies of HA crystals.HA crystals prepared in the electrolyte containing slow granule are rods in shape,the edge face of rod was a defined flat hex-agon and the surface of the crystal was smooth,and HA crystals are well-crystallized.%以微弧氧化后的钛合金为基体,采用水热电化学法制备了 HA/TiO 2涂层.利用 SEM、XRD 对涂层的表面形貌、物相组成进行了表征分析,通过 pH 微探针原位探测电极/电解液界面 pH 值的变化,研究了pH 值和缓冲剂对水热电化学沉积 HA/TiO 2涂层的影响.研究结果表明,微弧氧化膜有利于水热电化学沉积 HA,得到的 HA 晶体分布均匀、致密.当电解液pH 值在2~8时,pH 值升高有利于提高水热电化学沉积 HA 的结晶度,并促使 HA 沿(002)晶面生长.在水热电化学沉积 HA 过程中,电极表面的 pH 值随沉

  18. Effects on results of occult blood test in gastric juice at different pH values by two gold immunochromatographic assay strips%pH值对两种胶体金试剂条检测胃液潜血的影响

    Institute of Scientific and Technical Information of China (English)

    祁冬冬; 陈英利; 李翀; 张涛

    2012-01-01

    Objective:To study the influence of different PH values on the results of occult blood test in gastric juice. Methods:In the neutral environment, the minimum detection limit of two kinds of occult blood test strip was measured by gradually increasing the hemoglobin concentration; To adjust the PH value of fresh gastric juice in 5 mol/L NaOH solution and determine the critical PH value, hemoglobin can be detected at this critical PH value; at the critical PH value, hemoglobin concentration and measurement time were changed to detect their influence on the test results. Results; The minimum detection limit of two kinds of occult blood test strip respectively were 0.2 jig/ml and 0.4 μg/ml; As PH value of gastric juice was 3. 7, hemoglobin can not be detected, while PH < 3.7, increase of hemoglobin concentration can tentatively extend the time for positive occult blood test results. Conclusion:In PH <3.7 acid environment, the occult blood test will give the false negative results. Testing personnel can draw the right conclusions by adjusting the PH value of gastric juice and using microscope to observe the form of red blood cells.%目的:研究在胃液潜血实验中不同pH值对结果的影响.方法:在中性环境下逐渐增加血红蛋白浓度,测定两种潜血试纸条的最低检测限;用5 mol/L NaOH调节新鲜胃液的PH值,确定能检测出血红蛋白的临界pH值;在临界pH的环境里,改变血红蛋白浓度和测定时间,检测时间与浓度对检出率的影响.结果: 两种试纸条的最低检测限为0.2 μg/ml和0.4 μg/ml;pH值3.7时不能检测出血红蛋白;在pH <3.7的酸性环境里,血红蛋白浓度升高会暂时延长潜血实验结果阳性的时间.结论:胃液潜血实验在pH <3.7酸环境中检测,使结果出现假阴性,可以通过调节pH值和镜下观察得出正确结论.

  19. Impact of pH value on the chromatography behavior of four kinds of Benzodiazepines by HPLC%流动相pH值对地西泮、艾司唑仑、氯氮卓、三唑仑HPLC色谱行为的影响

    Institute of Scientific and Technical Information of China (English)

    王蔚昕; 张春水; 黄星

    2011-01-01

    在其它HPLC分析条件不变的前提下,本实验考察了地西泮、艾司唑仑、氯氮卓、三唑仑4种苯二氮卓类药物保留时间、拖尾因子、峰面积3个指标随流动相水相PH值改变而变化的趋势,初步总结了流动相pH值对4种药物HPLC色谱行为的影响.%Fixing other parameters, the change of the diazepam,Estazolam,Chlordiazepoxide and triazolam in retention time,tailing factor and peak area with PH value were studied in reversed phase high performance liquid chromatography. And the impact of PH value on the chromatography behavior of the four drugs was summarized preliminarily.

  20. Effects of Soil pH Value on Growth and Physiological Characters of Lupinus polyphylla Lindl%土壤pH对多叶羽扇豆生长及生理特性的影响

    Institute of Scientific and Technical Information of China (English)

    王庆; 刘安成; 庞长民; 张瑞博

    2012-01-01

    通过调节土壤酸碱度,研究不同土壤pH值对多叶羽扇豆的生长发育及生理特性的影响。结果表明:多叶羽扇豆植株随着土壤pH值的降低,叶片黄花率降低,叶绿素含量升高;POD活性升高,叶片内SOD活性的影响呈升高降低的趋势,2年生植株较1年生植株影响更为明显。土壤pH对多叶羽扇豆叶绿素a/b比值及CAT活性的差异性不显著。%Infection of different pH of soil on growth and physiological characters of Lupinus polyphylla was studied.Results indicated that with the decline of pH,the rate of yellow plant decreased while chlorophyll rose in content,the activities of peroxidase(POD) increased and SOD activities increased also.The chlorophyll content a/b and activity of catalase were no significant difference with soil pH change.

  1. PH og modernismen

    DEFF Research Database (Denmark)

    Ahnfeldt-Mollerup, Merete

    2012-01-01

    Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus.......Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus....

  2. 联合检测脐血与外周动脉血pH值对评估新生儿缺氧缺血性脑损伤的临床价值%Clinical value of combined detection of umbilical cord blood and peripheral arterial blood pH for evaluating neonatal hy-poxic ischemia encephalopathy

    Institute of Scientific and Technical Information of China (English)

    邵勤; 刁玉巧

    2015-01-01

    目的:测定新生儿缺氧缺血性脑病(HIE)患儿脐血及外周动脉血pH值,探讨其对新生儿 HIE的临床诊断价值。方法选择2011年6月至2013年6月产科自然分娩的足月新生儿917例,于出生后第1声啼哭前采集脐带血,检测脐动脉血pH值;对其中生后1 min Apgar评分小于或等于7分的138例新生儿于出生1 h抽取外周动脉血进行血气分析。分析其与新生儿HIE的关系。结果917例脐动脉血pH范围为7.22~7.51,平均pH值为7.31±0.14,pH<7.10作为预测新生儿 HIE的指标时其阳性预测值为55.38%,灵敏度60.00%,特异度96.61%,脐带血联合出生后1 h动脉血pH值预测HIE的阳性预测值95.74%、灵敏度88.26%,特异度97.10%。联合检测同单独检测比较,具有较高的灵敏度及阳性预测值。结论对于脐血p H<7.10的新生儿应当于生后复查外周动脉血pH值,脐血联合生后1 h动脉血pH值测定能客观评价新生儿出生时的状况,对新生儿 HIE的预测具有较高的临床价值。%Objective To detect the pH value of umbilical cord blood and peripheral arterial blood in the pa‐tients with neonatal hypoxic‐ischemic encephalopathy(HIC) and to investigate its clinical diagnostic value for HIE . Methods 917 healthy full‐term neonates by natural delivery in our hospital from June 2011 to June 2013 were select‐ed .The cord blood before first crying was collected and detected the umbilical arterial blood pH value .Among them , the peripheral arterial blood was collected for conducting the blood gas analysis in 138 cases of Apgar score ≤ 7 at 1 min after birth .Its correlation with neonatal HIE was analyzed .Results The umbilical arterial blood pH in 917 cases ranged 7 .22-7 .51 with the average pH value of 7 .31 ± 0 .14 .With pH<7 .10 as the prediction indicator of neonatal HIE ,the positive predictive value was 55 .38% ,the sensitivity and specificity were 60

  3. Investigation of Delivery Mode and Measuring Time on Neonatal Umbilical Arterial Blood pH Value%分娩方式及测量时间对新生儿脐动脉血pH值影响的探讨

    Institute of Scientific and Technical Information of China (English)

    卢德梅; 柳青叶; 尤小燕; 邹锁芳; 肖乐梅

    2012-01-01

      目的:探讨不同分娩方式不同分析时间对脐血pH值的影响,并研究两者之间的交互作用.方法:严格按照纳入标准选择研究对象,留取3份脐血,每份1 ml,分别于10 min、30 min、50 min时采用ABL77血气分析仪分析剖宫产和顺产产妇的脐血pH值,重复测量设计方差分析判定结果有无差异.结果:剖宫产产妇的脐血pH值高于顺产产妇,差异具有统计学意义(P<0.05).血气分析时间对脐血pH值影响较小.分娩方式和分析时间对脐血pH值影响不存在交互作用.结论:区别对待两种分娩方式的pH值是正确判定新生儿有无宫内窒息的重要前提.%  Objective:To assess whether delivery mode and analysis time can affect cord blood pH values which measured by umbilical cord blood gas analysis and further analyzed if there is interaction between these two factors on pH values.Method:Selected the participants according to the inclusion criteria strictly.Then collected 3 umbilical cord blood for analysis.Analysis of variance by repeated measurement design was used for analyze the differences between different groups.Result:The cord blood pH value for cesarean section pregnant women was higher than spontaneous labor pregnant women(significant at 0.05 level). The analysis time affect cord blood pH value weekly. There was no interaction between delivery mode and analysis time on pH value.Conclusion:It is necessary to distinguish their delivery mode before apply cord blood gas analysis result to diagnose neonatal asphyxia.

  4. A Nanocrystal-based Ratiometric pH Sensor for Natural pH Ranges.

    Science.gov (United States)

    Somers, Rebecca C; Lanning, Ryan M; Snee, Preston T; Greytak, Andrew B; Jain, Rakesh K; Bawendi, Moungi G; Nocera, Daniel G

    A ratiometric fluorescent pH sensor based on CdSe/CdZnS nanocrystal quantum dots (NCs) has been designed for biological pH ranges. The construct is formed from the conjugation of a pH dye (SNARF) to NCs coated with a poly(amido amine) (PAMAM) dendrimer. The sensor exhibits a well-resolved ratio response at pH values between 6 and 8 under linear or two-photon excitation, and in the presence of a 4% bovine serum albumin (BSA) solution.

  5. Lixiviação do picloram em argissolo vermelho-amarelo e latossolo vermelho-amarelo com diferentes valores de pH Picloram leaching on red-yellow latosol and red-yellow ultisol with different pH values

    Directory of Open Access Journals (Sweden)

    L. D'Antonino

    2009-01-01

    Full Text Available O objetivo deste trabalho foi avaliar o potencial de lixiviação do picloram em solos utilizados em pastagens no Brasil (Argissolo Vermelho-Amarelo e Latossolo Vermelho-Amarelo, com dois valores de pH. Para isso, amostras desses solos coletadas à profundidade de 0-20 cm (incubadas ou não com calcário por um período de 70 dias foram utilizadas como substrato para preenchimento de colunas de PVC de 10 cm de diâmetro por 50 cm de comprimento. Realizou-se um experimento em esquema de parcela subsubdividida, em delineamento inteiramente casualizado, com quatro repetições. Os tratamentos compreenderam a combinação de uma dose do herbicida picloram (160 g ha-1, três intensidades de chuva (40, 80 e 120 mm, três tipos de solo e 10 profundidades de amostragem nas colunas. As avaliações realizadas foram relativas ao desenvolvimento das plantas indicadoras nos substratos das colunas nas profundidades de 0-5, 5-10, 10-15, 15-20, 20-25, 25-30, 30-35, 35-40, 40-45 e 45-50 cm. Após o preparo das colunas, estas foram umedecidas e colocadas na posição vertical para drenagem do excesso de água. Após esse período, aplicou-se no topo delas o herbicida e, 12 horas depois, foram feitas as simulações das chuvas, especificadas de acordo com o tratamento. Elas permaneceram na posição vertical por mais 72 horas, para drenagem e lixiviação do herbicida. Após esse período, as colunas foram abertas longitudinalmente e colocadas na posição horizontal, semeando-se ao longo delas a espécie indicadora (Cucumis sativus. Conclui-se que o picloram apresentou alta taxa de lixiviação em todos os solos estudados e que sua movimentação no perfil dos solos foi influenciada pelo volume de chuva simulado, pelo pH do solo e, também, por outras características do solo, possivelmente pelo teor de matéria orgânica. O solo com baixo teor de matéria orgânica e pH mais elevado apresentou maior índice de lixiviação do picloram aplicado à camada

  6. Effect of Reaction Temperature and pH Value on Performances of Polyaniline/Epoxy Resin Composite Anti-corrosion Coatings%反应温度及pH值对聚苯胺/环氧树脂涂料防腐性能的影响

    Institute of Scientific and Technical Information of China (English)

    郝少娜; 甘孟瑜; 冯利军; 杨桔; 李志春; 贾春悦; 刘兴敏

    2011-01-01

    采用原位乳液聚合法,合成了聚苯胺/环氧树脂(PAn/EP)复合涂料,研究了聚合反应温度及体系pH值对其防腐性能的影响,并探讨了其防腐机理.结果表明,当反应温度为25℃、体系中PH=1时合成的PAn/EP复合涂料的防腐效果较好,并明显优于商品PAn/EP混合涂料.%The effects of reaction temperature and pH value on the corrosion resistance of polyaniline/epoxy resin (PAn/EP) composite coatings, which were prepared by chemical in-situ polymerization, were investigated by Tafel measurement. And the anti-corrosion mechanism of polyaniline/epoxy resin composite coatings was also discussed. The experimental results show that when the reaction temperature is 25 ℃ and the pH value is 1, the corrosion resistance of the composite coating is satisfactory, and it is better than PAn/EP mixed coatings.

  7. 不同pH值与电位耦合对牛血清白蛋白包被酒石酸长春瑞滨纳米粒制备工艺的影响%Effects of pH Value and Potential Coupling on the Preparation of Vinorelbine Tartrate Loaded Bovine Serum Albumin Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    李永; 赵修华; 祖元刚; 葛云龙; 王卫国

    2012-01-01

    pH value plays an important role in preparing nanoparticles using antisolvent procedure. In this research , vinorelbine tartrate loaded bovine serum albumin nanoparticles were prepared at different pH values. The preparation process of nanoparticles was analyzed in the view of potential coupling. The results indicated that vinorelhine tartrate and bovine serum albumin took the opposite charges at pH value from 4.5 -7.5. However, they took the same charge at pH 2. 5, 3. 5, 8. 5 and 9. 5. Especially, vinorelbine tartrate and bovine serum albumin took +4.48 and - 8.52 mV respectively. The particle size of vinorelbine tartrate loaded bovine serum albumin nanoparticles reached 193. 3 run and zeta potential reached -30. 86 mV in this condition. Moreover, the preparation process of nanoparticles were optimized at this pH value and the drug loading and encapsulation efficiency of this drug were approximately up to 45.6% and 90.6% , respectively.%在反溶剂法制备纳米粒过程中,pH值在一定程度上会对其产生影响.本文通过在不同酸碱环境下运用反溶剂法制备牛血清白蛋白包被酒石酸长春瑞滨纳米粒,进而借助于电位耦合作用来研究纳米粒制备工艺.研究结果表明:当pH=4.5至7.5时,酒石酸长春瑞滨和牛血清白蛋白带有异种电荷,而当pH =2.5,3.5,8.5,9.5时它们均带有同种电荷.当pH=7.5时,牛血清白蛋白带有负电荷即-8.52 mV,酒石酸长春瑞滨带有正电荷即+4.48mV.此时得到牛血清白蛋白包被酒石酸长春瑞滨纳米粒粒径为193.3 nm,Zeta电位为-30.86 mV,而且在该pH下对纳米粒制备工艺进行了优化,最终它的载药量和包封率达到了45.6%和90.6%.

  8. Prediction of pH value in industrialized aquaculture based on ensemble empirical mode decomposition and improved artificial bee colony algorithm%基于集合经验模态分解和人工蜂群算法的工厂化养殖pH值预测

    Institute of Scientific and Technical Information of China (English)

    徐龙琴; 李乾川; 刘双印; 李道亮

    2016-01-01

    The pH value in industrialized cultivation ponds is crucial to the survival ofLitopenaeus Vannamei. Grasping the trend of the pH value timely and accurately is the key for the high-density healthy Litopenaeus Vannamei culture. Therefore, in order to solve the low prediction accuracy of the single model in pH value prediction, this paper proposes a pH value combination forecasting model inLitopenaeus Vannamei industrialized cultivation based on ensemble empirical mode decomposition (EEMD) and improved artificial bee colony (IABC) algorithm. In the modeling process, the non-linear time sequences of the original pH value are de-noised and decomposed into a series of stable and uncoupling sequences by the EEMD. Based on the changed characteristics of each sequence, the appropriate forecasting method is selected and a new independent prediction model is established. The independent prediction values are reconstructed to obtain the ultimate prediction results. But whether the weight of the combined forecasting model is appropriate restricts the prediction accuracy and performance seriously. Therefore, we choose the IABC optimized method to seek the optimal weight of the combined forecasting model, which overcomes the blindness and the impact of human factors in parameter selection of the combined forecasting model in order to accelerate its convergence rate and forecast accuracy. The combinations of the best weights are obtained automatically after the optimization, and in the process the nonlinear combination prediction model of pH value in industrialized cultivation is constructed. With this model, the pH value change has been predicted for industrialized cultivation pond from September 8 to September 15 in 2014 in Zhanjiang City, Guangdong Province. The experimental results show that the proposed combination prediction model of EEMD-IABC has better prediction effect than the optimized back propagation neural network based on simulated annealing algorithm (SA-BPNN) and

  9. Continuous determination of the boiler water and industrial circulating cooling water pH value,alkalinity and chloride%锅炉水及工业循环冷却水的pH值、碱度和氯化物的连续测定

    Institute of Scientific and Technical Information of China (English)

    张居光; 吴继权; 黄容

    2013-01-01

    At automatic potentiometric titrator attached double electrodes, Using the direct potential and potentiometric titration methods, pH value, alkalinity and chloride concentration were obtained. pH combination electrode applies to the pH and alkalinity measured, and the reference pH electrode and indicator Ag electrode apply to precipitation titrated.The methods can be used for pH, alkalinity and chloride continuous determination of boiler water and industrial circulating cooling water. For high alkalinity and high chloride samples, the measured relative standard deviation is less than 0. 5%. For low alkalinity and chloride samples, the measured relative standard deviation is about 2%.%在双电极电位滴定仪上,应用直接电位法和电位滴定法依次获得pH值、碱度和氯化物浓度.pH复合电极不仅应用于pH值和碱度测定,还在沉淀滴定中发挥参比电极作用,银电极作为沉淀滴定的指示电极.该方法用于锅炉水和工业循环冷却水的pH值、碱度和氯化物连续的测定,对于碱度、氯化物浓度较高的样品,测定结果相对标准偏差小于0.5%.对于碱度、氯化物浓度较低的补水,测定结果的相对标准偏差约2%.

  10. Effect of temperature and pH value on cation exchange performance of a natural clay for selective (Cu2þ, Co2þ) removal:Equilibrium, sorption and kinetics

    Institute of Scientific and Technical Information of China (English)

    Ramzi Chalghaf; Walid Oueslati; Marwa Ammar; Hafsia Ben Rhaiem; Abdesslem Ben Haj Amara

    2013-01-01

    This work aims at investigating the strain effect, created by varying pH solution and continuous heating cycle, on the cation exchange process in the case of Na-rich montmorillonite sample in contact with bi-ionic solution with variable concentration, saturated respectively by Co2þ and Cu2þ cations. The ionic exchange process is characterized using XRD analysis obtained through the comparison of experimental XRD patterns with calculated ones, which allowed us to determine several structural parameters related to the nature, abundance, size, position and organization of exchangeable cation and water molecule in the interlamellar space along the cn axis. Indeed, the proposed theoretical models, for the stressed samples, show that the structure presents an interstratified hydration character and proves the coexistence of more than two ‘‘crystallite’’ specie in the structure. The perturbation types have an obvious effect on the selective exchange process for all stressed samples, where the interlayer space is characterized by the coexistence of more one exchangeable cation.

  11. Plant Habitat (PH)

    Science.gov (United States)

    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.

  12. 长期低剂量慢性辐射特殊环境人员唾液pH值、葡萄糖与淀粉酶含量检测与分析%Testing and analysis on pH value, concentration of glucose and amylase of salivary in persons in special environment of long term low dose radiation

    Institute of Scientific and Technical Information of China (English)

    王军; 程硕; 安源; 李刚; 郭静; 李广文; 高宗科; 赵增强; 张燕; 王东平; 陈云; 王宇欣; 李翠霞

    2012-01-01

    Objective To analyze the pH value, content changes of glucose and amylase of salivary in long term low dose radiation on exposure personnel. Methods We used accurate pH test paper to test salivary pH and used Beckman SYNCHRON CX7 large full automatic biochemical analyzer from the United States of America for detecting saliva glucose (glucose oxidase method). and salivary amylase (Amylase) concentrations ( Winslow's method). Results pH value ranged from 5.0 to 7. 1 (6.16 ±0.52) , glucose ranged from 0.67 to 1.95 (1. 320 ±0. 334)mmol/L, amylase ranged from 396. 80 to 1 190.60 (770. 508 ±42. 021) U/L. Conclusion The effect of long term and low dose of radiation on pH value, concentration of glucose and amylase in salivary should not be ignored.%目的 探讨长期低剂量慢性辐射特殊环境人员唾液pH值、葡萄糖与淀粉酶含量变化.方法 检测唾液pH值用精密pH试纸测定;使用美国Beckman SYNCHRON CX7大型全自动生化分析仪检测唾液中的葡萄糖含量(葡萄糖氧化酶法)与唾液淀粉酶(Amylase)浓度(温斯罗法).结果 唾液pH值为5.0~7.1(6.16±0.52);唾液葡萄糖为0.67 ~ 1.95(1.320±0.334) mmol/L;唾液淀粉酶为396.80~1 190.60(770.508±42.021) U/L.结论 长期小剂量慢性电离辐射对唾液pH值、葡萄糖与淀粉酶含量的影响不容忽视.

  13. Effect of the pH value on switchgrass seedling growth and development in hydroponics%水培条件下pH值对柳枝稷幼苗生长发育的影响

    Institute of Scientific and Technical Information of China (English)

    徐开杰; 史丽丽; 王勇锋; 李毛; 孙风丽; 刘曙东; 奚亚军

    2015-01-01

    土壤的pH值是限制植物生长发育的一个关键因素。柳枝稷是一种可作为牧草,水土保持的多年生C4能源植物。试验在水培条件下,利用裂区试验设计,以柳枝稷品种(系)为主区,水培液pH值为副区,对反映柳枝稷幼苗生长发育状况的指标进行统计分析。结果显示,随水培液pH值的酸碱强度增大,柳枝稷不同品种(系)幼苗的分蘖数、株高、苗鲜重、根冠比、根系活力以及净光合速率都极显著降低( P7.0)的适应能力更强,其中以西稷2号的抗逆性表现最好。因此应用柳枝稷在边际土壤地区推广种植时,要尽量避免强酸性土壤( pH值7. 0 ); ‘Xiji 2 ’ was the most resistant of all switchgrass varieties. Therefore, commercial switchgrass varieties should not be planted in marginal soils that are strongly acidic soil ( pH<5.0) , with‘Xiji 2’ representing the optimal variety for planting switchgrass on marginal soils.

  14. pH Basics

    Science.gov (United States)

    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…

  15. Predictive value of umbilical cord blood in combination with peripheral artery blood pH for neonatal hypoxic ischemia encephalopathy%联合检测脐血与外周动脉血pH值评估新生儿缺氧缺血性脑损伤

    Institute of Scientific and Technical Information of China (English)

    邵勤; 刁玉巧

    2014-01-01

    目的:测定新生儿缺氧缺血性脑病(HIE)患儿脐血及外周动脉血pH值,探讨二者联合检测对新生儿缺氧缺血性脑损伤的临床诊断价值。方法选择2011年6月至2013年6月河北医科大学附属邢台市人民医院产科自然分娩的足月新生儿917例,于生后第1声啼哭前采集脐血,检测pH值;对其中生后1 min Apgar评分≤7分的138例新生儿于生后1 h抽取外周动脉血进行血气分析。比较单独检测脐血、外周动脉血及二者联合检测对HIE的检验效能。结果 pH<7.10作为预测新生儿HIE的指标时其阳性预测值为55.38%,灵敏度60.00%,特异度96.61%,脐带血联合生后1 h 外周动脉血 pH值预测 HIE 的阳性预测值95.74%、灵敏度88.26%,特异度97.10%。结论对于脐血pH<7.10的新生儿应当于生后1 h复查外周动脉血pH值,二者联合检测对新生儿HIE的预测具有较高的临床价值。%Objective To explore the predictive value of pH in umbilical blood and peripheral arterial blood for the oc-curring of neonatal hypoxic-ischemic encephalopathy(HIE).Methods pH value of umbilical arterial blood was meas-ured in 917 cases of full-term neonates,sampled during June 2011 to June 2013,before the first cry.Blood gas was an-alyzed with peripheral arterial blood,sampled at 1 hour after born,from 138 cases whose Apgar scores were less or e-qual to 7 .The effectiveness of HIE detection was compared among umbilical blood,peripheral arterial blood and their combination.Results When umbilical arterial blood pH<7.10 was used as an indicator for HIE diagnosis,the posi-tive prediction value was 55.38%,sensitivity was 60.00% and specificity was 96.61%.When pH value of umbilical arterial blood and arterial blood was used together as the indicator for HIE,the positive prediction value was 95 .74%, sensitivity was 88.26%and specificity was 97.10%.Conclusion pH value of peripheral arterial blood is suggested

  16. 应激对反流性食管炎模型大鼠食管下段pH值及黏膜血流的影响%The Influence of pH Values and Blood Flow of Lower Esophageal in Reflux Esophagitis Model Rat by Stress

    Institute of Scientific and Technical Information of China (English)

    王瑞; 唐艳萍; 弓艳霞; 刘思邈; 康丽丽

    2016-01-01

    Objective To observe the influence of pH values and blood flow of lower esophageal in reflux Esophagitis model rat by stress, and to explore the effect of esophageal by psychological factor. Methods Pre⁃operative rats were randomly divided into 4 groups, control group, stress group, model group and stress plus mod⁃eling group, 15 rats in each group. Reflux Esophagitis rat model was established by the method of improved part cardiac muscle incision and part outlay-pyloric ligation. 7 days later, stress group and stress plus modeling group were induced by water immersion and immobilization. And then, the pH values of distal esophagus, the esophageal mucosal blood flow were compared. Results Compare with control group, the stress group lead to the pH values(3.21 ± 0.32)and the blood flow[(38.62 ± 6.11)BPU]down(P<0.01), the model group lead to the pH values(2.23 ± 0.27)and the blood flow[(30.16 ± 6.79)BPU]down(P<0.01); compare with model group, the stress plus model group lead to the pH values(2.01 ± 0.19)and the blood flow[(14.41 ± 7.04)BPU] down(P<0.01). Conclusion The stress could aggravate ischemia of esophageal mucosa and make pH values and the blood flow down.%目的::观察应激对反流性食管炎模型大鼠食管下段pH值及黏膜血流的影响,探讨心理因素在反流性食管炎发生、发展中的作用。方法:雄性Wistar大鼠,随机分为对照组、应激组、模型组、应激-模型组,每组15只。采用改良部分贲门肌切开术联合外置幽门部分结扎术制备大鼠反流性食管炎模型。造模后7 d,应激组和模型-应激组用水浸束缚法行应激实验。实验结束后,各组大鼠麻醉、剖腹,检测各组大鼠食管下段pH值、黏膜血流。结果:与对照组比较,应激组大鼠食管下段pH值(3.21±0.32)、黏膜血流[(38.62±6.11)BPU]均下降(P<0.01),模型组大鼠食管下段pH值(2.23±0.27)、黏膜血流[(30.16±6.79) BPU

  17. The Predictive Value of Combining Umbilical Arterial and Radial Arterial pH for Neonatal Hypoxic Ischemic Encephalopathy%脐带血联合动脉血pH值对新生儿缺血缺氧性脑病的预测价值

    Institute of Scientific and Technical Information of China (English)

    郭晓辉; 李华英; 夏俊霞; 沙文琼; 陈淑芳

    2011-01-01

    目的 探讨脐带血联合动脉血pH值对新生儿缺血缺氧性脑病(HIE)的预测价值.方法 选取2009年4月至2011年1月在深圳市人民医院分娩的无严重畸形的7 456例活产婴儿作为研究对象,对其脐动脉血pH值与新生儿缺血缺氧性脑病的相关性进行分析,并随机选择481例新生儿于出生后1h行桡动脉血气分析.结果 7 456例脐动脉血pH为7.10~7.42.以脐带血pH<7.10为指标预测新生儿HIE的阳性预测值为35.57%,敏感性42.06%.脐带血联合出生后1h动脉血pH值预测HIE的敏感性为60.00%,阳性预测值71.79%.联合检测与单项检测临床符合率比较,差异有统计学意义(P<0.01).结论 脐带血pH<7.10且出生1h动脉血pH<7.3对新生儿缺血缺氧性脑病有预测意义.脐动脉血pH<7.10的新生儿应常规于出生后复查桡动脉血pH值.%Objective To study the predictive value of combining radial arterial blood and umbilical arterial blood gas analysis for hypoxic ischemic encephalopathy (HIE). Methods 7 456 neonates without severe deformity,bom in Shenzhen People's Hospital from April 2009 to January 2011, were recruited into our research. The correlation between umbilical arterial blood gas analysis and neonatal hypoxic ischemic encephalopathy were analyzed. 481 cases were randomly selected for radial arterial blood gas analysis an hour after birth. Results The pH values of umbilical arterial blood ranged from 7.10 to 7.42. There was a significant correlation between HIE and the pH value of umbilical arterial blood (P < 0.05). Taken pH<7.10 as an indicator to assess neonatal HIE,the positive predictive value and sensitivity were 35.5% and 42.06%, respectively. The positive predictive value and sensitivity of combining radial arterial with umbilical arterial blood gas analysis were 71.79% and 60.00%, respectively. The difference in clinical coincidence rates between combined test and single test was statistically significant (P < 0

  18. 聚合溶液pH值对染料敏化太阳电池中聚吡咯对电极结构和性能的影响%Influence of pH Values on the Structure and Performance of a Polypyrrole Counter Electrode for Dye-Sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    苏佳; 芦姗; 王莎莎; 张雪华; 付玉彬; 贺涛

    2014-01-01

    The pH of the solution used to produce an electro-polymerized polypyrrole (PPy) film has a significant impact on the morphology and properties of the resulting film and, by extension, on the electrocatalytic activity of the film for the I-/I3-redox reaction. Accordingly, the performance of dye-sensitized solar cells (DSSCs) based on PPy counter electrodes (CEs) is affected by solution pH. In this study, p-toluene sulfonate ion-doped PPy (PPy-TsO) CEs on fluorine-doped tin oxide (FTO) glass substrates were fabricated using an electrochemical method under a constant bias in solutions with various pH values. The effect of the pH of the synthetic solution on the morphology, structure, and electrocatalytic activity during the I-/I3-redox reaction of the obtained PPy CEs was thoroughly investigated by scanning electron microscopy (SEM), UV-Vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). A pH value of 2.0 was found to represent the optimal value, since the PPy-TsO film produced at this pH exhibited the highest degree of doping, the longest conjugation length, and the highest catalytic activity. When working as the CE of a DSSC, this film also showed the highest power conversion efficiency. Films synthesized at pH values either above or below 2.0 exhibited inferior properties and lower performance when in DSSCs.%电化学合成聚吡咯(PPy)时,聚合电解液的pH值对PPy薄膜的形貌和性质有较大的影响,进而影响PPy薄膜对I-/I3-的电催化活性以及基于PPy对电极(CE)的染料敏化太阳电池(DSSCs)的光电转换性能.本文采用电化学恒电位方法,在掺杂氟的SnO2(FTO)导电玻璃上合成出了对甲苯磺酸根离子掺杂的聚吡咯(PPy-TsO)电极,并将其作为DSSCs的对电极.通过改变吡咯聚合时聚合电解液的pH值,借助扫描电镜(SEM)、紫外-可见(UV-Vis)吸收光谱、X-射线光电子能谱(XPS)和循环伏安(CV)等表征技术,详细探

  19. Design of PH sensor signal acquisition and display system

    Science.gov (United States)

    Qian, Huifa; Zhang, Quanzhu; Deng, Yonghong

    2017-06-01

    With the continuous development of sensor manufacturing technology, how to better deal with the signal is particularly important. PH value of the sensor voltage generated by the signal as a signal, through the MCU acquisition A / D conversion, and ultimately through the digital display of its PH value. The system uses hardware and software to achieve the results obtained with the high-precision PH meter to strive to improve the accuracy and reduce error.

  20. The clinical significance of the measurement of umbilical arterial blood lactate and pH value in the diagnosis of fetal dis-tress%脐动脉血乳酸及pH值测定在胎儿窘迫诊断中的临床意义

    Institute of Scientific and Technical Information of China (English)

    余凤花; 李少芳; 张杰; 王佳; 潘颖

    2014-01-01

    Objective To explore the clinical significance of the measurement of umbilical arterial blood lactate and pH value in the diagnosis of fetal distress.Methods We collected 1024 cases of pregnant women whose pregnancy were more than 36 weeks and all these pregnant women were treated at our hospital from March 2011 to June 2014. Acording to the standard of clinical diagnosis of fetal distress and the abnormal rate of fetal heart,all these patients were divided into case group(fetal distress syndrome)totaling 588 cases and control group(non-fetal distress syn-drome)totaling 436 cases.When the fetus not yet have breathe,we immediately mearured the umbilical arterial blood lactate and pH value and analysised the results.Results The lactate value of case group were higher than the control group,the former group's pH value (<7.20)was significantly increased compared with the after group,and comparing with the control group,the difference has statistically significant(P<0.05).Conclusion The umbilical arterial blood lactate and pH value measurement used in clinical will increase the rate of clinical diagnosis of fetal distress,facilitate early intervention,prevent neonatal asphyxia and help to reduce neonatal mortality.%目的:探讨脐动脉血乳酸及 pH 值测定在胎儿窘迫中的临床价值。方法采集我院2011年3月至2014年6月收治的妊娠大于36周孕妇1024例,按照临床诊断胎儿窘迫标准及胎心监护异常分为研究组(有胎儿窘迫征)588例和观察组(无胎儿窘迫征)436例,在胎儿娩出尚未呼吸前立即行胎儿脐动脉血乳酸及 pH 值测定,并进行结果分析。结果研究组乳酸值较对照组高,pH值<7.20前组较后组显著增多,与观察组对比,差异有统计学意义(P<0.05)。结论脐血乳酸及 pH值测定应用于临床将提高临床胎儿窘迫诊治率,便于及早进行干预,预防新生儿窒息的发生,有利于降低新生儿病死率。

  1. Consideration of Factors Affecting Strip Effluent PH and Sodium Content

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. [Savannah River Site (SRS), Aiken, SC (United States)

    2015-07-29

    A number of factors were investigated to determine possible reasons for why the Strip Effluent (SE) can sometimes have higher than expected pH values and/or sodium content, both of which have prescribed limits. All of the factors likely have some impact on the pH values and Na content.

  2. Effect of two mouthwashes on salivary ph.

    Science.gov (United States)

    Belardinelli, Paola A; Morelatto, Rosana A; Benavidez, Tomás E; Baruzzi, Ana M; López de Blanc, Silvia A

    2014-01-01

    To analyze the effect of two mouthwashes on salivary pH and correlate it with age, buffer capacity and saliva flow rate in healthy volunteers, a crossover phase IV clinical study involving three age-based groups was designed. Two commercial mouthwashes (MW), Cool Mint ListerineR (MWa) and Periobacter R (MWb) were used. The unstimulated saliva of each individual was first characterized by measuring flow rate, pH, and buffer capacity. Salivary pH was evaluated before rinsing with a given MW, immediately after rinsing, 5 minutes later, and then every 10 min (at 15, 25, 35 min) until the baseline pH was recovered. Paired t-test, ANOVA with a randomized block design, and Pearson correlation tests were used. Averages were 0.63 mL/min, 7.06, and 0.87 for flow rate, pH, and buffer capacity, respectively. An immediate significant increase in salivary pH was observed after rinsing, reaching average values of 7.24 (MWb) and 7.30 (MWa), which declined to an almost stable value 15 minutes. The great increase in salivary pH, after MW use shows that saliva is a dynamic system, and that the organism is capable of responding to a stimulus with changes in its composition. It is thus evident that pH of the external agent alone is not a good indicator for its erosive potential because biological systems tend to neutralize it. The results of this study enhance the importance of in vivo measurements and reinforce the concept of the protective action of saliva.

  3. Effects of mixture of chelating agents with different pH values on phytoextraction and heavy metals removal%不同pH值混合螯合剂对土壤重金属淋洗及植物提取的影响

    Institute of Scientific and Technical Information of China (English)

    郭晓方; 卫泽斌; 许田芬; 史学峰; 吴启堂

    2011-01-01

    The mixture of chelators (MC) can remove heavy metals from contaminated soils, but the appropriate Ph value and its impacts on the following phytoextraction need to be elucidated. Pot experiments were carried out to evaluate the efficiency of heavy metals removal by MC at different Ph values (2.75, 5, 7 and 9). The ptytoextraction by Sedum alfredii in the soil after washing with MC were also assessed. Result showed that soil washing with MC at Ph 5 and 7 significantly increased the leached Cd, Pb and Cu. Heavy metals removal enhanced by addition of Ca2+ into MC instead of Na+ or K+. The biomass of S. Alfredii enhanced after soil washing with MC at Ph value 7 and 9, but the concentrations of Cd and Zn in S. Alfredii and phytoextraction rates reduced compared with the initial MC at Ph 2.75. In this combined technology, Zn and Cd removal mainly depended on phytoextraction, its removal rates were from 30% to 40% of the total soil Cd and from 6.5% to 6.9% for Zn. Pb and Cu removal relied on soil washing, the removal rates were from 2.3% to 2.6% of the total soil Pb and from 1.6% to 2.0% for Cu. Overall, the combination of soil washing with Ph value 9 MC and phytoextraction was preferred to remove simultaneously Cd, Zn, Pb and Cu from the acidic contaminated soil and to decrease its available pools in the soil.%为了得出混合螯合剂(MC)淋洗去除重金属的最佳pH值以及对后续植物提取重金属的影响,用Ca(OH)2将pH值为2.75的MC提高至pH值5、7和9,对重金属污染土壤进行了盆栽淋洗试验,而后种植东南景天(Sedum Alfredii),测定淋出液及植物重金属含量.另外,通过浸提试验研究了含有不同阳离子的MC对重金属淋洗效果的影响.结果表明,pH值为5和7的MC显著提高了Cd、Pb和Cu的淋出率.与Na+、K+离子相比,Ca2+的存在能够提高MC对重金属的淋洗去除.pH值7和9的MC淋洗土壤后提高了东南景天的生物量,但是降低东南景天中Cd和Zn的浓度,导致其植物提

  4. 不同浸提剂pH对工业污水污泥中重金属浸出的影响%Experimental Study on Influence of pH Value of Extractant on the Leachability of Heavy Metals in Sewage Sludge Consist of Industrial Wastewater

    Institute of Scientific and Technical Information of China (English)

    黄浩

    2012-01-01

    The leaching tests of heavy metals in sewage sludge consist of industrial wastewater were conducted under different pH values of extractant by employing the "solid waste extraction procedure for leaching toxicity(GBS086.2-1997)" of China in the base of the contents of Zn, Gu, Pb, Cr, Mn, Ni elements. The results showed that the sludge with higher levels of Mn and Zn, followed by Cu and Ni, while the higher toxicity of Pb and Cr is low. The fractions of different elements in the sewage sludge have very different combination forms. The pH values of extraction agents have an important impact on the leaching of heavy metals in sewage sludge, in which the Zn, Mn, Ni, Cu leaching volume of the largest in the pH of 7 and Fe has a greater fluctuation. Different pH values of the leaching amount of metals have very different, which may be related with the process of adsorption/desorption, complexation/ dissociation and the dissolution/precipitation/co-precipitation and other factors, and their leaching mechanism requires further study.%在研究工业污水污泥中6种重金属(Zn、Cu、Pb、Cr、Mn、Ni)含量的基础上,应用固体废物浸出毒性的浸出方法(GB5086.2-1997)以不同pH值的浸提剂对污泥中重金属的浸出特性进行了实验研究。结果表明:污泥中Mn和Zn含量较高,其次为Cu和Ni,而毒性较大的Pb和Cr含量较低。浸提剂的pH对污泥中重金属的浸出具有重要的影响,其中污泥中的Zn、Mn、Ni、Cu最大浸出量在pH为7左右,而Fe则有较大的波动。不同pH值中金属的浸出量有很大的差异,这可能与浸提过程中的吸附一解吸过程、络合一解离过程和溶解一沉淀/共沉淀等因素有关。

  5. Influence of circumcision on pH values of various penile portions and significance for nursing%包皮环切术对阴茎局部皮肤黏膜pH的影响及护理指导意义

    Institute of Scientific and Technical Information of China (English)

    刘晓红; 梁伟珍; 方向红; 姜海洋; 栾华

    2012-01-01

    Objective To observe the influence of circumcision on various penile portions and its significance for nursery of circumcision. Method The Ph values of urethral orifice, coronary sulcus and penile base were detected with electrical Ph meter before and after circumcision in 13 cases and analyzed statistically with paired t-test. Result The Ph values in all portions detected above increased significantly at the time just after operations and recovered at first day after operations except urethral orifice remained high Ph values until tenth day. Conclusions It is verified in present study that local anesthesia and circumcision significantly alter the acid status of penile skin and mucous membrane, especially for urethra. The present study should be contributory for improving the nursery of circumcision sutures.%目的 探讨局部麻醉下包皮环切术对阴茎不同部位皮肤黏膜pH的影响及护理指导意义.方法 应用电子酸度计测定13例包皮环切术患者术前后尿道外口、冠状沟和阴茎根部pH值.了解局部麻醉下包皮环切术对阴茎不同部位皮肤黏膜pH的影响.结果 尿道外口、冠状沟和阴茎根部术后pH值均明显升高,但冠状沟和阴茎根部皮肤术后第1d即恢复到术前水平,而尿道外口于10 d时pH值仍未恢复到术前水平.结论 局部麻醉和包皮环切术可改变阴茎皮肤黏膜,尤其是尿道外口酸性状态,应向患者做好相关知识的健康教育.

  6. 17-4 PH and 15-5 PH

    Science.gov (United States)

    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.

  7. pH条件对短短芽孢杆菌FJAT-0809-GLX次生代谢物产生的影响%Effects of Initial pH Value for the Fermentation of Brevibacillus brevis FJAT-0809-GLX on the Generation of Secondary Metabolites Substances

    Institute of Scientific and Technical Information of China (English)

    陈峥; 刘波; 朱育菁; 胡桂萍; 车建美; 唐建阳

    2012-01-01

    Components of FJAT-0809-GLX fermentation liquid inlO different initial pH values were analyzed by GC-MS. Eleven compounds with the match degree above 90 % were identified. The compounds found commonly in these 10 fermentation liquid was Hexahydro-pyrrolo [1,2-a] pyrazine-1, 4-dione. There were two sorts of functional compounds in the FJAT-0809-GLX fermentation liquids; one is volatile compounds which relate to the special aroma of this fermentation liquid, including 5-methyl-2-Furancarboxaldehyde, Maltol, Benzeneacetaldehyde, n-Hexa-decanoic acid, Oleic Acid, and 2-Hydroxy-3-methyl-2-cyclopenten-l-one. The other sort of functional compound had antiseptic and bacteriostatic effect, including Maltol, 2-Furanmethanol and Hexahydro-pyrrolo [1, 2-a] pyrazine-1,4-dione and 5-(hydroxymethyl)-2-Furancarboxaldehyde. The fermentation liquid with the initial pH value of 6 to 12 had inhibitory activity against K88. The pH value 7 had the best inhibitory activity; the diameter of inhibition zone was 20. 33mm. Different initial pH values led to different terminal pH value, and then affect the generation properties of secondary metabolites of Brevibacillus brevis FJAT-0809-GLX.%应用GC-MS对10种不同初始pH条件下发酵的FJAT-0809-GLX发酵液的丙酮萃取液进行初步成分鉴定,从这10种发酵液中得到匹配率≥90%成分11种,各发酵液中的成分存在明显差异,其中共有成分1种,为六氢吡咯并[1,2-a]吡嗪-1,4-二酮.在匹配率≥90%成分中,功能性成分按其功能可分为2类,一类为挥发性或芳香类物质,与该发酵液具有的特殊香气有关,包括5-甲基呋喃醛、2-甲基-3-羟基-4-吡喃酮、苯乙醛、棕榈酸、顺式十八碳-9-烯酸、甲基环戊烯醇酮;另一类为防腐或抑菌类成分,包括2-甲基-3-羟基-4-吡喃酮、2-呋喃甲醇、六氢-吡咯[1,2-a]吡嗪-1,4-二酮和5-羟甲基糠醛.初始pH 6~12的发酵液对大肠杆菌K88均有抑制效果,其中初始pH为7的抑菌效

  8. pH matters

    DEFF Research Database (Denmark)

    Inaba, Masanori; Quinson, Jonathan; Arenz, Matthias

    2017-01-01

    We investigated the influence of the ink properties of proton exchange membrane fuel cell (PEMFC) catalysts on the oxygen reduction reaction (ORR) activity determined in thin film rotating disk electrode (TF-RDE) measurements. It was found that the adaption of a previously reported ink recipe...... to home-made catalysts does not lead to satisfying results, although reported work could be reproduced using commercial catalyst samples. It is demonstrated that the pH of the catalyst ink, which has not been addressed in previous TF-RDE studies, is an important parameter that needs to be carefully...

  9. Effect of Solution pH Value on Chloramphenicol Extraction Detected by Gas Chromatography-Mass Spectrometry%酸碱度对气相色谱-质谱联用法检测氯霉素提取的影响

    Institute of Scientific and Technical Information of China (English)

    王峰恩; 陈子雷; 王文博; 丁蕊艳; 杜红霞; 霍鲁格

    2011-01-01

    为使检测结果更准确,研究了溶液酸碱度对氯霉素提取的影响.在9种不同pH值的水溶液中添加氯霉素标准品,乙酸乙酯提取后,用N,0-双(三甲基硅基)三氟乙酰胺(BSTFA)-三甲基氯硅烷(rMCS)进行硅烷化处理,用正己烷溶解后,使用气相色谱-质谱联用法(GC/MS)检测氯霉素衍生物.通过全扫描质谱图和NIST标准质谱图的对比,对氯霉素衍生物进行定性确定;通过测定特征离子m/z 225的值对其定量;再将提取后的水溶液残液全部调至pH=5.5左右,重新检测以确认氯霉素在一些样品中未检出的原因.结果表明,强酸强碱中的氯霉素发生不可逆的分解,在提取氯霉素时应保持中性偏酸环境以达到最佳提取效果.%To make sure the results more accurate, the effects of different solution pH values on the chloramphenicol extraction were studied. The standard chloramphenicol was added into 9 kinds of solutions' with different pH values, and then extracted with ethyl acetate after 24 hours. After silylation processing with N, O - di (trimethyl silicon - based) three fluorine acetamide (BSTFA) - trimethyl chlorine silicon hydride (TMCS) and dissolved by normal hexane, the chloramphenicol derivatives were detected by gas chromatogra-phy -mass spectrum (GC/MS). The qualitative detection was conducted through the comparison between the entire chromatograph chart and the NIST standard mass spectrum chart, while the quantitative determination was conducted through detecting the value of characteristic ion m/z 225. At last, the pH value of the residual sample after extraction was adjusted to about 5.5 and detected again to confirm the reason why some chloram phenicol was undetectable. The results showed that the chloramphenicol could be decomposed irreversibly in strong acid or alkali, and the neutral meta - acid solution was better for extraction.

  10. Eukaryotic diversity at pH extremes

    Directory of Open Access Journals (Sweden)

    Linda A. Amaral-Zettler

    2013-01-01

    Full Text Available 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 7 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 Analysis (SIMPER 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.

  11. The Value of Value

    DEFF Research Database (Denmark)

    Sørensen, Asger

    parts of business ethics given prominence to especially one term, namely `value'. The question that interests me is the following: What does the articulation of ethics and morality in terms of values mean for ethics and morality as such. Or, to put the question in a more fashionably way: What...... is the value of value for morality and ethics?To make things a bit more precise, we can make use of the common distinction between ethics and morality, i.e. that morality is the immediate, collective and unconscious employment of morals, whereas ethics is the systematic, individual and conscious reflections...

  12. 小于34周早产儿胃液pH值与呼吸暂停相关的护理研究%Gastric juice PH value in preterm infants of less than 34 weeks and nursing care for apnea

    Institute of Scientific and Technical Information of China (English)

    林明珠; 陈丽梅; 温碧霞; 谭碧连

    2013-01-01

    Objective To seek the methods of correcting gastric juice pH values and nursing care for apnea induced by gastroesophageal reflux cause.Methods 60 preterm infants of less than 34 weeks without complications were divided into a control group (30 infants) and a study group (30 infants).The control group received traditional care; and the infants in this group were fed milk on the amount of 4 mL/kg/time,every three hours for one time,had a postprandial free position,and received low-dose erythromycin or motilium on doctor' s order daily.The study group was fed milk on the amount of 0.5ml/kg/time,every two hours for one time on the first day,and then fed with an daily increase in milk of 0.5ml/kg,received a prone position with the head at a height of 60 degrees after feeding; the gastric juice pH values were detected.Incidence of apnea was observed and recorded.Whole milk with a PH value of 6 to 7 coincided with normal gastric juice pH value.The rate of gastric juice pH value of less than 4 and the incidence rate of apnea were compared between the two groups.Results The rate of gastric juice pH value of less than 4 and the incidence rate of apnea were significantly reduced in the study group.Conclusions Correction of gastric juice pH value in preterm infants of less than 34 weeks can obviously lower the incidence rates of gastroesophageal reflux and apnea and thus has significant clinical significance.%目的 寻求纠正小于34周早产儿胃液pH值预防过酸的胃液返流入食管中段刺激迷走神经反射性致非窒息性呼吸暂停护理方法.方法 本研究选取60例胎龄小于34周无合并症早产儿,其中对照组30例,观察组30例.对照组:按传统护理,每天按4 ml/次/kg计算给与每次奶量,Q3H喂养一次,餐后自由体位,每天按医嘱予小剂量红霉素或者吗叮林药物治疗.观察组:Q2H喂奶一次,第一天按0.5 ml/次/kg计算给与每次奶量[1],以后每天递增奶量按0.5 ml/次/kg计算;喂养后头高60

  13. Adding value(s)

    DEFF Research Database (Denmark)

    Carré, David

    2015-01-01

    , 1992). In response, behavioral economics (Camerer, 1999) has shown that agents have values other than optimization underpinning their decisions. Therefore, concerns arose regarding which values are guiding the agent but not about how such values became relevant for the agent. In this presentation, I......Most economic inquires revolve around agents making decisions. Getting the ‘best value’, it is assumed, drives such decisions: gaining most while risking least. This assumption has been debunked by showing that people does not always choose neither maximum benefit nor less risk (Kahneman & Tversky...... will explore the consequences of shifting to the latter perspective, i.e. looking for the generative framework of values. Here I argue that economic behavior should also be seen as a sense-making process, guided by values that are chosen/rejected along with fellow human beings, in specific socio...

  14. 不同pH值条件下蒙脱石散对配伍药物体外吸附作用的影响%Adsorption effects of montmorillonite powder on its compatible drugs at different pH values in vitro

    Institute of Scientific and Technical Information of China (English)

    陈爱瑛; 叶小弟; 程敏; 缪云萍; 方颖颖; 郑高利

    2011-01-01

    AIM To investigate the adsorption of montmorillonite powder interacting with its commonly used compatible drugs including norfloxacin, ofloxacin, Yulian tablets, ranitidine, famotidine, acyclovir and ribavirin in artificial gastric and intestinal fluid at different pH values in vitro. METHODS The artificial gastric and intestinal fluid at different pH values were used to dissolve the drugs, then montmorillonite powder was added into the drug solutions. The drug contents were determined by HPLC method, and the adsorption rates were calculated. RESULTS The adsorption rate of montmorillonite powder to palmatine and berberine in Yulian tablets were both higher than 95% , to norfloxacin and ofloxacin were about 80% , to acyclovir and ribavirin were lower than 10%. Ranitidine and famotidine decreased with the increase of PH value. CONCLUSION The adsorption effects of montmorillonite powder on these drugs are different. The dosing interval should be considered when the drugs with high adsorption rate were administered.%目的 研究在不同pH值人工胃液和人工肠液中蒙脱石散对常与其配伍药物诺氟沙星、氧氟沙星、萸连片、雷尼替丁、法莫替丁、阿昔洛韦、利巴韦林的体外吸附作用.方法 取蒙脱石散分别加入到用不同pH人工胃液和人工肠液溶解的上述药物溶液中,用高效液相色谱法测定药物含量,计算吸附率.结果 蒙脱石对萸连片中巴马汀、小檗碱的吸附率达95%以上;对诺氟沙星、氧氟沙星吸附率达80%左右;对阿昔洛韦、利巴韦林吸附率比较小,在10%以下;对法莫替丁和雷尼替丁的吸附率随着pH值的增加而降低.结论 蒙脱石散对上述药物有不同的吸附作用,吸附率大的药物配伍应用时注意服药间隔时间.

  15. Refined X-ray Structures of Haloalkane Dehalogenase at pH 6.2 and pH 8.2 and Implications for the Reaction Mechanism

    NARCIS (Netherlands)

    Verschueren, Koen H.G.; Franken, Sybille M.; Rozeboom, Henriëtte J.; Kalk, Kor H.; Dijkstra, Bauke W.

    1993-01-01

    The crystal structure of haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 has been refined at 1.9 Å resolution at two different pH values, the pH of crystallization (pH 6.2) and the pH of optimal activity (pH 8.2), to final R-factors of 16.8% and 16.4%, respectively. Both models show goo

  16. Refined X-ray Structures of Haloalkane Dehalogenase at pH 6.2 and pH 8.2 and Implications for the Reaction Mechanism

    NARCIS (Netherlands)

    Verschueren, Koen H.G.; Franken, Sybille M.; Rozeboom, Henriëtte J.; Kalk, Kor H.; Dijkstra, Bauke W.

    1993-01-01

    The crystal structure of haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 has been refined at 1.9 Å resolution at two different pH values, the pH of crystallization (pH 6.2) and the pH of optimal activity (pH 8.2), to final R-factors of 16.8% and 16.4%, respectively. Both models show goo

  17. Laryngopharyngeal pH measurement

    OpenAIRE

    Spurrier, E; Clancy, M; Deakin, C

    2004-01-01

    Methods: Cohorts of unconscious adult ED and elective surgical patients were recruited. The posterior pharyngeal wall pH was measured immediately before and after intubation. Pharyngeal pH was used to indicate risk of aspiration, and pH change to assess the efficacy of cricoid pressure.

  18. MANUFACTURE OF FIBER OPTIC SENSORS TO MEASURE THE PH WATER

    Directory of Open Access Journals (Sweden)

    Bushra R. Mahdi

    2016-07-01

    Full Text Available A fiber-optic pH sensor based on evanescent wave penetration is presented. Evanescent wave penetration is generated by removing the clad and contact the core with the solution. Testing samples were perpetrated by add a strong acid (HCL or a strong base (NaOH at distilled water to produce different value of pH (from 4 to 13. To determine the absorption or transmission of the evanescent waves, that generate after where obtained on appropriate calibration curve to determine a wide range of pH, by using pH indicators. Where using methyl red, by add fixed amounts of this dyes to the water samples were obtained on samples with colors vary with pH values. Calculate the transmission and absorption with draw a relationship between the transmissions or absorption with the pH values, to obtain on suitable curves, considered as calibration curves. Calibration curve for methyl red is best, where extends (from 4 to 12 for pH value. Can calculate the pH value for any water sample to tested, by the add the same ratios of the organic dyes it used.

  19. Empirical Essays on the Labor Market Outcomes of PhD Graduates

    DEFF Research Database (Denmark)

    Pedersen, Heidi Skovgaard

    During the past decade, policy makers have accentuated the need for more PhDs to drive innovation and use their research skills to push the technological frontier. The public sector in Denmark has financially supported a doubling of the number of enrolled PhD students based on a strong belief...... that PhDs accelerate growth. A major objective has been to direct more PhDs to the industry to use their skills to monetize knowledge. However, we have limited evidence on how PhDs are absorbed into the labor market, how the market values PhD labor, and how PhDs value the possibility to work...

  20. Differential Sensor for PH Monitoring of Environmental Objects

    Directory of Open Access Journals (Sweden)

    Romanenko Sergey

    2016-01-01

    Full Text Available Differential pH sensor is proposed. Reference electrode and measuring electrode are the same type. Reference electrode is immersed in standard buffer solution with known pH value. The differential pH sensor has longer service life as compared with the traditionally used sensors with silver chloride reference electrode. Ultrasonic cleaning system is proposed to clean the primary measuring transducer from pollution that form as result of silting during long-term operation with the sensor.

  1. Effect of Norepinephrine and Dopamine in the pH Value of Gastric Mucosa in Patiens with Septic Shock%去甲肾上腺素、多巴胺对感染性休克患者胃黏膜pH值的影响

    Institute of Scientific and Technical Information of China (English)

    郭俊; 王夜明

    2015-01-01

    目的:探讨去甲肾上腺素、多巴胺对感染性休克患者胃黏膜pH值(Phi)的影响。方法:选择64例感染性休克患者,按所使用的血管活性药物分为两组,A组为去甲肾上腺素组,B组为多巴胺组,每组各32例。观察用药前和用药后6 h血流动力学指标的改变,同时观察用药前和用药后6、12、24、48 h胃黏膜pH值的变化。结果:两组用药前血流动力学指标和胃黏膜pH值比较差异无统计学意义(P>0.05)。用药后6 h后,两组的平均动脉压(MAP)明显升高但差异无统计学意义(P>0.05);两组的中心静脉压(CVP)与中心静脉血氧饱和度(ScvO2)均升高,且A组高于B组,B组心率(HR)明显高于A组,两组比较差异均有统计学意义(P0.05)。结论:去甲肾上腺素、多巴胺均可改善感染性休克患者全身血流动力学状态,但去甲肾上腺素优于多巴胺,去甲肾上腺素较多巴胺可使胃黏膜pH值(Phi)明显升高。%Objective:To investigate the effect of Norepinephrine and Dopamine in the pH value of gastric mucosa in patients with septic shock.Method:64 patients with septic shock were selected and divided into Norepinephrine treatment group(group A) and Dopamine treatment group(group B),32 cases in each group.The change of hemodynamic index before and after medication 6 hours and the pH value of gastric mucosa before and after medication 6,12,24 and 48 hours were observed.Result:Before medication,the hemodynamic index and the pH value of gastric mucosa of two groups had no significant differences(P>0.05).After treatment,mean arterial pressure(MAP) of two groups significantly improved,but the difference was no statistically significant(P>0.05).The central venous pressure (CVP)and central venous oxygen saturation(ScvO2) of two groups were significantly improved and group A was higher than group B,heart rate of group B increased significantly than group A

  2. pH值对粗对苯二甲酸加氢精制Pd/C催化剂性能的影响%EFFECT OF pH VALUE ON THE PERFORMANCE OF Pd/C CATALYST FOR HYDROPURIFICATION OF CRUDE TEREPHTHALIC ACID

    Institute of Scientific and Technical Information of China (English)

    堵文斌; 王继元; 朱庆奋; 陈韶辉

    2011-01-01

    A series of Pd/C catalysts for hydropurification of crude terephthalic acid (CTA)were prepared by impregnating with solutions having various pH values, and the prepared catalysts were characterized by XRD and TEM techniques. Effects of impregnation pH values on the performance of catalyst during removing p-carboxy benzaldehyde (4-CBA), the main impurity in CTA, were investigated. Results showed that catalyst prepared with an impregnation solution pH value of 3.0 exhibited the best catalytic activity, under a reaction temperature of 280 ℃, H2 partial pressure of 0. 6 MPa and a reaction time of 1.0 h,the conversion of 4-CBA over said Pd/C catalyst was almost 100 %. In this catalyst the palladium particles were highly dispersed on the surface of active carbon and presented as microcrystalline structure. A comparison study was carried out between said Pd/C catalyst (prepared at pH value of 3.0 )and an import catalyst. Under severe testing conditions and after repeating testing, the deactivation tendency and palladium sintering behavior of these two catalysts were similar, which indicated that the hydropurification performance of these two catalysts was in the same level.%采用不同pH值的浸渍液制备了粗对苯二甲酸(CTA)加氧精制Pd/C催化剂,考察了浸渍液的pH值对CTA中的主要杂质对羧基苯甲醛(4-CBA)的加氢精制性能的影响,并采用XRD、TEM等手段对催化剂进行了表征.结果表明,浸渍液的pH值为3.0时,金属Pd以微晶的形式高度分散在活性炭载体上,Pd/C催化剂的活性最高,在反应温度280℃、H2分压0.6 MPa、反应时间1.0 h的条件下,Pd/C催化剂上的4-CBA的转化率接近100%.经过多次苛刻的重复反应试验,pH值为3.0条件下制备的Pd/C催化剂与某进口催化剂的活性衰减趋势以及Pd晶粒的烧结情况相当,说明自制Pd/C催化剂的加氢性能已经达到该进口催化剂的性能水平.

  3. pH值和螯合剂复合作用对正极材料Li3V2(PO4)3/C性能的影响%Influence of pH value and chelating reagent on performance of Li3V2(PO4)3/C cathode material

    Institute of Scientific and Technical Information of China (English)

    向伟; 唐艳; 王雁英; 钟本和; 方为茂; 刘恒; 郭孝东

    2013-01-01

    The Li3V2(PO4)3/C composite cathode material was synthesized via sol-gel method using three different chelating agents (citric acid,salicylic acid and polyacrylic acid) at pH value of 3 or 7.The crystal structure,morphology,specific surface area and electrochemical performance of the prepared samples were investigated by X-ray diffraction (XRD),scanning electron microscopy (SEM),cyclic voltammetry (CV),electrochemical impedance spectroscopy (EIS) and galvanostatic charge/discharge test.The results show that the effects of pH value on the performance of the prepared materials are greatly related to the chelating agents.With salicylic acid or polyacrylic acid as the chelating reagent,the structure,morphology and electrochemical performance of the samples are greatly influenced by the pH values.However,the structure of the materials with citric acid as the chelating agent does not change as pH value changes,and the materials own uniform particle size distribution and good electrochemical performance.It delivers an initial discharge capacity of 113.58 mA·h/g at 10C,remaining as high as 108.48 mA·h/g after 900 cycles,with a capacity retention of 95.51%.%使用不同的螯合剂(柠檬酸、水杨酸和聚丙烯酸)在不同的pH值条件下,采用溶胶-凝胶法合成Li3V2(PO4)3/C正极材料.通过X射线衍射(XRD)、扫描电镜(SEM)、循环伏安(CV)、电化学阻抗谱(EIS)以及恒流充放电测试等方法,研究材料的结构、形貌及电化学性能.结果表明,pH值对材料性能的影响与所采用的螯合剂有很大的关系.当采用水杨酸和聚丙烯酸为螯合剂时,升高pH值对材料的结构、形貌和电化学性能有较大的负面影响.而采用柠檬酸为螯合剂时,材料结构无变化且颗粒分布更均匀,高倍率放电性能和循环性能也得到改善,10C首次放电容量为113.58 mA·h/g,循环900次后容量保持率为95.51%.

  4. Eukaryotic diversity at pH extremes.

    Science.gov (United States)

    Amaral-Zettler, Linda A

    2012-01-01

    Extremely acidic (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.

  5. Ureolytic nitrification at low pH by Nitrosospira spec.

    NARCIS (Netherlands)

    De Boer, W.; Laanbroek, R.

    1989-01-01

    An ureolytic ammonium-oxidizing chemolithotroph belonging to the genus Nitrosospira was shown to nitrify at pH 4.5 in a pH-stat with urea as a substrate. With ammonium as the sole substrate nitrification did not occur at pH values below 5.5. Nitrosomonas europaea ATCC 19718 and Nitrosospira briensis

  6. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2003-12-01

    Full Text Available Report of PhD Dissertations. Guido Antonioli Conservator pacis et iustitie. La signoria di Taddeo Pepoli a Bologna (1337-1347, Tesi di dottorato di ricerca in Filologia romanza e cultura medievale (XIII ciclo, Università degli Studi di Bologna, 2001   Elisabetta Filippini «In vassallatico episcopi permanere debent». Rapporti vassallatici e concessioni beneficiali dei vescovi di Cremona fra X e XIII secolo, Tesi di dottorato di Ricerca in Storia Medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2003   Marco Meschini, Innocenzo III e il "negotium pacis et fidei" in Linguadoca tra il 1198 e il 1215, Tesi di dottorato di ricerca in Storia medievale, Università Cattolica del Sacro Cuore, 2003   Fabrizio Ricciardelli The Politics of Exclusion in Florence (1215-1434, thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in History, University of Warwick, Department of History, April 2003 Renata Salvarani Baptizare pueros et decimas dare. Cura delle anime, strutturazione ecclesiastica e organizzazione delle campagne in area gardesana fra VIII e XIII secolo (diocesi di Brescia, Verona, Mantova e Trento, Tesi di dottorato in Storia medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2002-2003   Vito Sibilio Le parole della prima crociata, Tesi di dottorato di ricerca in Storia dei centri delle vie e della cultura dei pellegrinaggi nel medioevo euromediterraneo, Università degli studi di Lecce, 2003

  7. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2000-06-01

    Full Text Available Report of PhD Dissertations.   Miguel Calleja Puerta El conde Suero Vermúdez, su parentela y su entorno social. La aristocracia leonesa en los siglos XI y XII, Tesis de doctorado en Historia, Universidad de Oviedo (España, 2000   Adele Cilento Potere e monachesimo nella Calabria bizantina: relazioni e interferenze (secc. IX-XI, Tesi di dottorato di ricerca in Storia medievale (X ciclo, Università degli Studi di Torino, 2000   Amedeo De Vincentiis Firenze e i signori. Sperimentazioni istituzionali e modelli di regime nelle signorie fiorentine degli Angioini (fine XIII - metà XIV secolo, Tesi di dottorato di ricerca in Storia medioevale (XI ciclo, Università degli Studi di Milano, 1999   Marco Folin Il sistema politico di un antico Stato italiano: i ducati estensi nella prima Età moderna (1452-1598, Tesi di dottorato di ricerca in Storia, Scuola Normale superiore di Pisa, 2000   Barbara Frale Guardiani del Santuario. Le radici orientali del processo contro l’ordine del Tempio (1128 - 1314, Tesi di dottorato di ricerca in Storia sociale d’Europa (XI ciclo, Università "Ca’ Foscari" di Venezia, 2000

  8. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2003-06-01

    Full Text Available Reporto of PhD Dissertations.   Mario Dalle Carbonare Società, potere e clientele nell’Irlanda altomedievale (secoli V-IX, Tesi di dottorato di ricerca in Storia sociale europea, Università "Ca' Foscari" di Venezia, 2003 Vieri Mazzoni La legislazione antighibellina e la politica oligarchica della Parte Guelfa di Firenze nel secondo Trecento (1347-1378, Tesi di dottorato di ricerca in Storia Medievale (ciclo XII, Università degli Studi di Firenze   Alma Poloni Pisa dalle origini del movimento popolare alla discesa di Ludovico il Bavaro. I gruppi dirigenti cittadini tra continuità e trasformazione, Tesi di dottorato di ricerca in Storia dell'Europa nel medioevo, Università degli studi di Pisa, 2003   Andrea Puglia Potere marchionale, amministrazione del territorio, società locali dalla morte di Ugo di Tuscia a Guelfo VI di Baviera (1001-1160, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Milano, 2003

  9. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2010-06-01

    Full Text Available Report of PhD dissertations. Andrea Brugnoli Una storia locale: l’organizzazione del territorio veronese nel medioevo: trasformazioni della realtà e schemi notarili (IX-metà XII secolo, Tesi di dottorato di ricerca in Scienze Storiche e Antropologiche (XXII ciclo, Università degli Studi di Verona, 2010   Luca Filangieri Famiglie e gruppi dirigenti a Genova (secoli XII-metà XIII, Tesi di dottorato di ricerca in Storia medievale (XXII ciclo, Università degli Studi di Firenze, 2010   Jakub Kujawi ski Wernakularna kolekcja historiograficzna z rękopisu francuskiego nr 688 z Biblioteki Narodowej w Paryżu. Studium źródłoznawcze (La raccolta dei volgarizzamenti delle opere storiografiche nel manoscritto francese 688 della Biblioteca Nazionale di Parigi, Tesi di dottorato, Università “Adam Mickiewicz”, Facoltà di Storia, Pozna, a.a. 2009/2010   Marta Longhi I signori “de Radicata”. Strategie di affermazione familiare e patrimoniale nel Piemonte dei secoli XII-XIV, Tesi di dottorato di ricerca in Istituzioni, Società, Religioni dal Tardo Antico alla fine del Medioevo (XX ciclo, Università di Torino, 2008

  10. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-06-01

    Full Text Available Report of PhD Dissertations. Francesco Barone Istituzioni, società ed economia a Catania nel tardo medioevo (XIV-XV secolo, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Laura Berti Ceroni Il territorio e le strutture di Cesarea e Classe tra tarda antichità e alto medioevo in rapporto con Ravenna, Tesi di dottorato di ricerca in Storia e Informatica, Università degli studi di Bologna, 2002-2003.   Marco Bicchierai Poppi dalla signoria dei conti Guidi al vicariato del Casentino (1360-1480, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Firenze, 2004   Emanuela Garimberti Spatiosa ad habitandum loca. Luoghi e identità nella Historia Langobardorum di Paolo Diacono, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004   Lorenzo Tanzini Sistemi normativi e pratiche istituzionali a Firenze dalla fine del XIII all’inizio del XV secolo, Tesi di dottorato di ricerca in Storia medievale (XVI ciclo, Università degli Studi di Firenze, 2004   Stefania Tarquini Pellegrinaggio e asseto urbano di Roma, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo, Università degli studi di Lecce, 2003

  11. Enkephalins: Raman spectral analysis and comparison as function of pH 1-13

    DEFF Research Database (Denmark)

    Abdali, Salim; Refstrup, Pia; Nielsen, O.F.

    2003-01-01

    Raman spectral studies are carried out on Leu- and Met-enkephalin as a function of the pH value in the range of 1-13. The molecules are dissolved in KCI solvent and the pH is controlled at each value. Spectral analyses reveal the dependence of the structural conformation on the pH, and a comparis...

  12. Hyperpolarised organic phosphates as NMR reporters of compartmental pH.

    Science.gov (United States)

    Jensen, Pernille Rose; Meier, Sebastian

    2016-02-07

    Organic phosphate metabolites contain functional groups with pKa values near the physiologic pH range, yielding pH-dependent (13)C chemical shift changes of adjacent quaternary carbon sites. When formed in defined cellular compartments from exogenous hyperpolarised (13)C substrates, metabolites can thus yield localised pH values and correlations of organelle pH and catalytic activity.

  13. The effects of pH on the adsorption of mercury on laterite from Guizhou Province, China

    Institute of Scientific and Technical Information of China (English)

    YU Xiaohong; ZHU Lijun; GUO Baiwei; LUO Yi

    2006-01-01

    In this paper, the role of pH value on the adsorption of Hg2+ on the laterite from Guizhou Province was studied. The lower pH is unfavorable to the adsorption of Hg2+ whereas the higher pH is favorable to the adsorption of Hg2+. When pH reached a certain value, the amount of Hg2+ adsorption reached the maximum. Then the amount of Hg2+ adsorption was reduced with increasing pH value.

  14. 异丙酚在不同pH值环境下对苯甲酰苯甲酸ATP诱发的巨噬细胞嘌呤2X7受体电流的影响%Effect of propofol on BzATP induced P2X7-gated currents in RAW264.7 macrophages under different extracellular pH values

    Institute of Scientific and Technical Information of China (English)

    刘红亮; 戴体俊

    2011-01-01

    To investigate the sensitivity of P2X7 receptor to its specific agonist BZATP and the effect of propofol on P2X7-gated currents in RAW264. 7 macrophages under different extracellular pH values. METHODS-RAW264. 7 cells were cultured, and whole-cell patch clamp technique was used. BZATP (10 - 10000 pimol/L) was applied for 5 seconds, the currents were recorded, and the EC50 value of BZATP was achieved under the extracellular pH value of 7. 4 or 6. 0. Propofol (1 -100 jumol/L) was applied to the cells for 1 min, then BZATP with two times EC50 value was applied, the IC50 or EC50 value of propofol was achieved under different extracellular pH values. To investigate the effect of propofol on the dose-response curve of B2ATP under different extracellular pH values, propofol with IC50 value was applied, and BZATP (10-10000 fimol/L) was applied for 5 seconds, the EC50 value of BZATP was achieved. RESULTS :BZATP could induce the inward cur-rents in a dose-dependent manner, and the EC50 value of BZATP was (112 ±26) μmol/L and (643 ±87) μmol/L at extracellular pH value of 7. 4 or 6. 0. Propofol could inhibit P2X7-gated currents at pH 7. 4, and the IC50 value was (31 ±6) μmol/L; but propofol increased P2X7-ga-ted currents at pH 6. 0, and the EC50 value was (38 ±6) fxmol/L. The IC50 value of propofol made the dose-response curve of BZATP shifted rightward at pH 7.4, or leftward at pH 6.0. CONCLUSION: The sensitivity of P2X7 receptor to BZATP decreases when extracellular pH value changes from 7. 4 to 6. 0. Propofol with clinically related concentrations could inhibit P2X7-ga-ted currents at pH 7. 4, and increase P2X7-gated currents at pH 6. 0 extracellularly.%目的:观察在不同pH值条件下巨噬细胞膜嘌呤2X7(P2X7)受体电流对其特异性激动剂苯甲酰苯甲酸ATP (BZATP)的敏感性及异丙酚对P2X7受体电流的影响.方法:应用培养的RAW264.7巨噬细胞,采用全细胞膜片钳技术,向细胞施加BZ ATP(10~10000 μmol/L)5 s,记录电流,

  15. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2005-06-01

    Full Text Available Report of PhD Dissertations. Federica Cengarle Le investiture feudali di Filippo Maria Visconti (1412-1447, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Milano, 2005 Silvia Coazzin Liberi domini totius castri. L'aristocrazia rurale "minore" nel Senese e nella Toscana meridionale. Forme di egemonia, assetto sociale e patrimoniale di lignaggi, famiglie e gruppi consortili di castello (secc. XI-XIV, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Maria Elena Cortese Signori e castelli. Famiglie aristocratiche, dominati signorili e trasformazioni insediative nel comitatus fiorentino (fine X-metà XII secolo, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Patrizia Meli Gabriele Malaspina marchese di Fosdinovo: il condottiero ed il politico, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 Federica Pessotto La Morea franca. Economia e istituzioni tra Oriente e Occidente nei secoli XIII e XIV, Tesi di dottorato di ricerca in Istituzioni, Società e Religioni dal Tardoantico alla fine del Medioevo, Università degli studi di Torino, 2003 Lorenzo Pubblici Dal Caucaso al Mar d’Azov. L’impatto dell’invasione mongola nella Caucasia fra nomadismo e civiltà sedentaria (1204-1395, Tesi di dottorato di ricerca in Storia medievale, Università degli studi di Firenze, 2005 [01/05] Riccardo Rao "Comunia". Risorse collettive e patrimoniali dei maggiori comuni subalpini (secoli XII - inizio XIV, Tesi di dottorato di ricerca in Storia medioevale, Università degli Studi di Milano, 2005 Alessandro Soddu Feudalesimo e potere signorile in Sardegna nei secoli XI-XIV.  La signoria territoriale dei Malaspina, Tesi di dottorato di ricerca in Storia, Università "Pompeu Fabra" di Barcellona, 2004

  16. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2002-06-01

    Full Text Available Report of PhD dissertation. Laura Baietto Una politica per le città. Rapporti fra papato, vescovi e comuni nell'Italia centro-settentrionale da Innocenzo III a Gregorio IX, Tesi di dottorato di ricerca in Storia Medievale, Università degli Studi di Torino, 2002   Giuseppe Banfo Compresenze e sovrapposizioni di poteri territoriali di qualità diversa tra X e XIII: il caso del basso Monferrato, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2002   Francesca Dell'Acqua La vetrata tra l'età tardo imperiale e l'altomedioevo: le fonti, l'archeologia, Tesi di Perfezionamento in Storia dell'Arte Medievale, Scuola Normale Superiore di Pisa, 2001   Primo Giovanni Embriaco I vescovi di Albenga e gli sviluppi signorili nella Liguria occidentale (secoli XI-XIII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2001   Antonella Ghignoli Documenti e proprietà altomedievali. Fondamenti e problemi dell'esegesi storica delle fonti documentarie nello specchio della tradizione delle carte pisane dei secoli VIII-XI, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002   Vito Loré Espansione monastica e mutamenti politici. La Trinità di Cava nei suoi rapporti con i sovrani longobardi e normanni e con l'aristocrazia territoriale. Secoli XI-XII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002   Rosaria Stracuzzi Messina nel '400, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Palermo, 2001   Stefania Tamburini Le "portate" ecclesiastiche nel piviere di San Giovanni in Firenze nel 1427. Spunti per una riflessione sul patrimonio ecclesiastico della diocesi fiorentina,Tesi di dottorato di ricerca in Storia e informatica, Università degli Studi di Bologna, 2001

  17. 磷酸盐缓冲液的浓度和pH对革胡子鲶肠道抗菌蛋白/肽分级盐析的影响%Effect of Concentration and pH Value of Phosphate Buffer on Gradient Ammonium Sulphate Fractionation of Antibacterial Protein/peptide from Intestine of African Catfish ( Clarias gariepinus)

    Institute of Scientific and Technical Information of China (English)

    王存; 王晓梅; 季延滨; 徐敏; 戴伟; 潘宝平

    2011-01-01

    [目的]探讨磷酸盐缓冲液的pH和浓度在分级盐析时,对革胡子鲶肠道各组分蛋白/肽的影响.[方法]以不同浓度和pH的磷酸盐缓冲液作为组织匀浆缓冲液,在硫酸铵饱和度为20% 、40%、60%、80%和100%的条件下,对革胡子鲶肠道抗菌蛋白/肽进行分级盐析,并对盐析产物进行称重、电泳检测和抑菌活性分析.[结果]磷酸盐缓冲液的pH为6.0或7.4时,其浓度对盐析产物产量、蛋白沉淀和抑菌效果无显著影响.而pH为8.0、浓度为0.05 mol/L时,硫酸铵饱和度为60%和100%的粗蛋白/肽的产量显著高于浓度为0.02 mol/L的磷酸盐缓冲液粗蛋白含量;大分子蛋白能更好地在硫酸铵饱和度为20%和40%时沉淀下来,而在饱和度为60%、80%和100%能获得分子量相对较小的抗菌蛋白/肽.磷酸盐缓冲液的pH和浓度对抑菌效果无显著影响.[结论]pH 8.0,浓度为0.05 mol/L的磷酸盐缓冲液更适于革胡子鲶肠道抗菌蛋白/肽的提取.%[Objective] The effects of the concentration and pH value of phosphate buffer on the proteins/peptides in each fraction of African catfish in testine were studied. [ Method] The antibacterial proteins/peptides from intestine of African catfish were fractionation by a graded ammonium sulfale (AS) precipitation technique and the fractions were oblained at 20%,40%,60%,80% and 100% saturation with ammo nium sulfale. Each fraction was weight and detected by SDS-PAGE and its antibacterial activity was analyzed. [Result] The concentration of phosphate buffer al pH 6.0 and 7.4 didn't show significant effect on these indexes. At the pH 8.0, concentration of phosphate buffer also didn't show significant effect on antibacterial activity of each fraction. However, the yields of the crude extracts oblained at 60% and 100 % saturated AS were higher in phosphate buffer concentration of 0.05 mol/L than that in 0.02 mol/L phosphate buffer. And the relatively high molecular

  18. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-12-01

    Full Text Available Report of PhD Dissertations. Massimo Della Misericordia Divenire comunità. Comuni rurali, poteri signorili, identità sociali in Valtellina e nella montagna lombarda nel tardo medioevo, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Torino, 2003   Mariano Dell’Omo Il monastero di S. Liberatore alla Maiella centro dell’irradiazione di Montecassino nell’Abruzzo medievale e moderno. Contributo alla storia dell’organizzazione patrimoniale e della civiltà monastica cassinese nell’Italia centrale attraverso i documenti di S. Liberatore conservati nell’Archivio di Montecassino. Introduzione storica, paleografica e archivistica. Edizione dei documenti più antichi (†798-1000 e regesti di quelli posteriori (1005-1735, Tesi di dottorato in Storia Ecclesiastica, Facoltà di Storia Ecclesiastica, Pontificia Università Gregoriana di Roma,  2004   Giulia Lorenzoni Conquistare e governare la città. Forme di potere e istituzioni nel primo anno della signoria viscontea a Bologna (ottobre 1350-novembre 1351, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Bologna, 2004   Federica Monteleone Il viaggio di Carlo Magno in Terra Santa. Un’esperienza di pellegrinaggio nella tradizione europea occidentale, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo   Francesca Pucci Donati Fra teorie mediche e pratica quotidiana: i calendari dietetici dell’Occidente latino altomedievale (secoli IX-XI, Tesi di dottorato di ricerca in Storia medievale (XV ciclo, Università degli studi di Bologna, 2004 Alberto Ricciardi L’Epistolario di Lupo di Ferrières come fonte per la storia degli intellettuali nell’età di Carlo il Calvo, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004   Francesco Paolo Terlizzi I trattati dell'Anonimo Normanno: ricerche di ecclesiologia, Tesi

  19. Continuous fetal tissue pH measurement in labor.

    Science.gov (United States)

    Young, B K; Noumoff, J; Klein, S A; Katz, M

    1978-11-01

    Fifty-one women in labor had continuous monitoring of fetal scalp tissue pH, fetal heart rate by ECG, and uterine contractions. A miniature pH electrode secured by a double spiral fetal ECG electrode was used for measurement of fetal pH every 15 seconds. The results were correlated with fetal scalp blood pH values obtained simultaneously. Fetal scalp sampling is intermittent, requires repeated scalp incisions, is subject to errors due to air mixing and coagulation of the blood sample, and is uncomfortable for the parturient. Placement of the tissue pH electrode allows continuous data recording with the minimum discomfort to the patient and the least number of fetal scalp incisions. Clinical use of the tissue pH electrode might be a practical alternative to fetal scalp samples, if the data obtained accurately reflect fetal status.

  20. 石灰-石膏法烟气脱硫系统塔内浆液pH值及密度测量改进%Improvement in pH Value and Density Measurement for Slurry in Tower of Lime-Gypsum FGD Systems

    Institute of Scientific and Technical Information of China (English)

    梁磊; 马洪玉; 丁华; 梁咏

    2012-01-01

    火电厂石灰-石膏法烟气脱硫系统所用pH计及密度计的取样探头易结垢、磨损,测量管路堵塞频繁,导致脱硫塔装液pH值和密度的测量出现偏差甚至数据失真.为此,设计了改进型pH计取样装置,并采用隔膜压力变送器代替传统密度计.结合山西大土河焦化有限责任公司热电一分厂3×75t/h循环流化床锅炉烟气脱硫工程,介绍二者的使用原理及应用情况.实践结果表明,改进型pH计取样装置可有效保护取样探头,具有较好的实用性和经济性;隔膜压力变送器具有监测脱硫塔内浆液密度和液位的双重功能,且维护工作量小,更符合工程应用的需求.%Scaling and wearing tend to happen on the sarnpling probe of pH meters and density meters used in lime-gypsum FGD system of thennal power plants,which leads to frequent clogging in the measuring pipeline and deviation, even distortion in pH value and density measurement for the desulfurization tower slurry.Therefore, an improved pM sampling device is designed, adopting the diaphragm pressure transmitter instead of the traditional densimeter. Combined with the FGD project for three 75-1/h circulating fluidized bed boilcrs in the No. 1 combined heat and power plant for Shanxi Datuhe Coking and Chemical Co Ltd., the principle and application of the design is introduced,The experimental results show that the improved pH sampling device can effectively protcct the samplig probe with better practicability and economics. The diaphragm pressure transmitter also has dual functions, I.e., mnnitoring the densily and liquid level of the slurry in the desulfurization tower, which requires less maintenance work and is more suitable for engineering upplication.

  1. 脐动脉血pH值对评价新生儿窒息的应用价值研究%The research of clinical application value in evaluating the newborn asphyxia with Umbilical arterial blood pH value

    Institute of Scientific and Technical Information of China (English)

    张良江; 赖瑶纯; 薛彦锐

    2013-01-01

    目的 探讨研究脐动脉血pH值对评价新生儿窒息的应用价值.方法 从2011年6月~2012年12月于本院阴道分娩的新生儿中随机抽取480例新生儿,将其依据新生儿Apgar评分分为正常组(Apgar评分>7分)和窒息组(Apgar评分≤7分),对新生儿的脐动脉血pH值进行监测,分析研究其与Apgar评分间的关系.结果 Apgar评分>7分462例、Apgar评分≤7分18例;脐动脉血pH值检测:pH≥7.20共461例,pH﹤7.20共19例;脐动脉血pH值与新生儿1 min内Apgar评分呈正相关,并且正常组和窒息组pH值差异显著具有统计学意义(P < 0.05).脐动脉血pH值的敏感度和特异度分别为90.0%、99.8%,Apgar评分的敏感度和特异度分别为45.0%、98.0%,差异有统计学意义(P < 0.05).pH 值异常与羊水污染度呈正相关,随着污染度加重发生率上升,差异显有统计学意义(P < 0.05).结论 对于评价新生儿窒息,脐动脉血pH值比Apgar评分有更高的敏感度和特异度,能直接揭示窒息的病理生理本质和反映缺氧、酸中毒的严重程度,对及时采取措施防止并发症的发生有重要意义,应在临床中推广应用.

  2. Mapping Soil pH Buffering Capacity of Selected Fields

    Science.gov (United States)

    Weaver, A. R.; Kissel, D. E.; Chen, F.; West, L. T.; Adkins, W.; Rickman, D.; Luvall, J. C.

    2003-01-01

    Soil pH buffering capacity, since it varies spatially within crop production fields, may be used to define sampling zones to assess lime requirement, or for modeling changes in soil pH when acid forming fertilizers or manures are added to a field. Our objective was to develop a procedure to map this soil property. One hundred thirty six soil samples (0 to 15 cm depth) from three Georgia Coastal Plain fields were titrated with calcium hydroxide to characterize differences in pH buffering capacity of the soils. Since the relationship between soil pH and added calcium hydroxide was approximately linear for all samples up to pH 6.5, the slope values of these linear relationships for all soils were regressed on the organic C and clay contents of the 136 soil samples using multiple linear regression. The equation that fit the data best was b (slope of pH vs. lime added) = 0.00029 - 0.00003 * % clay + 0.00135 * % O/C, r(exp 2) = 0.68. This equation was applied within geographic information system (GIS) software to create maps of soil pH buffering capacity for the three fields. When the mapped values of the pH buffering capacity were compared with measured values for a total of 18 locations in the three fields, there was good general agreement. A regression of directly measured pH buffering capacities on mapped pH buffering capacities at the field locations for these samples gave an r(exp 2) of 0.88 with a slope of 1.04 for a group of soils that varied approximately tenfold in their pH buffering capacities.

  3. Characteristic of Zn2+/Cd2+/NH4+transport in soils with different pH value and ionic strength%不同pH值和离子强度下土壤Zn2+/Cd2+/NH4+的运移特征

    Institute of Scientific and Technical Information of China (English)

    孙莹莹; 徐绍辉

    2013-01-01

      为探究锌、镉及铵态氮在土壤中的运移特征,该文通过室内土柱混合置换试验,分析了不同 pH 值和离子强度对锌、镉、铵态氮(Zn2+、Cd2+、NH4+)在土壤中运移的影响;获得了示踪剂Br和Zn2+/Cd2+/NH4+的穿透曲线(breakthrough curves,BTCs),并对试验结果进行了模拟。研究表明:Zn2+/Cd2+/NH4+在土壤中运移时,运移速度:NH4+>Zn2+>Cd2+,pH 值越高,Zn2+/Cd2+/NH4+的出流时间越晚,峰值越低;离子强度越大,出流时间越早,峰值越高。描述溶质运移的非平衡两点模型(two-site model,TSM)能够较好地模拟 Zn2+/Cd2+/NH4+在土壤中的运移,pH值越高,模拟得到的分配系数Kd值越大(以Zn2+为例,由3.853增大到4.386),f值越小(以Zn2+为例,由0.231减小到0.006),分形系数β值很小且无明显变化规律;离子强度越大,模拟得到的分配系数Kd值越小(以Zn2+为例,由4.023减小到到3.381),f值及分形系数β值均很小且无明显变化规律。该研究对深入了解Zn2+/Cd2+/NH4+在土壤中的运移机理、提出污染土壤修复措施提供科学依据。%  In order to make a thorough inquiry of Zn, Cd, NH4+transportation in soils, the effect of pH and ionic strength on Zn, Cd, NH4+transport in soils were studied, through a stable flow miscible displacement experiment. Breakthrough curves (BTCs) of the tracer bromide (Br) and Zn2+/Cd2+/NH4+were obtained in these soil column experiments. With the software HYDRUS-1D, the local equilibrium assumption (LEA) model was used to simulate the observed BTCs of Br. Then we estimated the porosityθand dispersion coefficient D and got the soil column migration model parameters. Through adjusting the value of Kd,β,α, f, two-site model (TSM) was used to simulate the BTCs of Zn2+/Cd2+/NH4+with software HYDRUS-1D. Based on the analysis of BTCs observation, it turned out that transport velocity of Zn2+/Cd2+/NH4+is

  4. 短期放牧强度对典型草原土壤有机碳及pH值的影响%Effects of Short-term Grazing Intensities on Soil Organic Carbon and pH Value in the Typical Steppe

    Institute of Scientific and Technical Information of China (English)

    萨仁高娃; 曹芙; 敖特根; 叁巴; 王成杰

    2014-01-01

    选择克氏针茅典型草原放牧的西门塔尔牛为研究对象,分析研究短期不同放牧强度(零放牧、轻牧、中牧、重牧)对草地土壤有机碳及pH值的影响,以探索典型草原适宜的载畜率。结果表明:①0~20 cm土层,有机碳含量随着放牧强度的增大而降低,且在重度放牧条件下呈显著差异;而20~30 cm土层,有机碳含量大小顺序为重牧>中牧>零放牧>轻牧,且重牧与轻牧呈显著差异。②土壤pH值随着放牧强度的增大而显著增加。③垂直分布上,土壤有机碳含量随着土层深度的增加而减少,而pH值大小顺序均呈现为10~20 cm>20~30 cm>0~10 cm。由此可见,制定适宜的载畜率,维持土壤养分平衡,是遏制草地退化的必要措施。%Taking Simmental cattle grazed in the typical steppe of Stipa krylovii Roshev as the research object, the effects of different short-term grazing intensities (non-grazing, light-grazing, moderate-grazing and heavy-grazing)on the soil organic carbon and pH value in the typical steppe of Inner Mongolia were analyzed and the suitable stocking rate of the typical steppe was discussed, in order to alleviate the grassland soil degradation and enhance the sustained utilization of grassland. The results showed that the content of organic carbon in 0-20 cm soil layer decreased with the increase of grazing intensities and there was significant difference under the heavy-grazing conditions. The organic carbon content in 20-30 cm soil layer was heavy-grazing>moderate-grazing>non-grazing>light-grazing and there was significant difference between the heavy-grazing and light-grazing. The soil pH value significantly increased as the grazing intensities decreased. The organic carbon content in soil decreased as the soil depth increased and the order of pH value was 10-20 cm>20-30 cm>0-10 cm in the vertical distribution. Therefore it was essential for preventing the grassland

  5. Study on Characteristic Bands Selection of Lamb pH Value Based on Hyperspectral Imaging and Partial Least Squares(PLS)%基于高光谱图像和偏最小二乘的羊肉pH值特征波段筛选研究

    Institute of Scientific and Technical Information of China (English)

    朱荣光; 段宏伟; 姚雪东; 邱园园; 马本学; 许程剑

    2016-01-01

    Characteristic bands method selection and subsequent spectral extraction has a great influence on the hyperspectral model performance.For rapid and accurate detection of mutton pH value,the effects of 2 band-selection methods on PLS models of mutton pH based on HSI technique were carried out and discussed.Initially,the preprocessing method of second derivative (2D),multiplicative scatter correction (MSC)and mean-centering together was implemented on the representative spectra of mutton muscle portion.Then,2 methods of synergy interval partial least square (siPLS)and the combination of synergy interval partial least squares with genetic algorithm (siPLS-GA)were used to extract the characteristic bands in the spectral range of 473~1 000 nm.Finally,2 PLS models of lamb pH value were established with the corresponding characteristic bands,and were al-so compared with the effect of full-band PLS model.The results indicated that the effect of siPLS-GA-PLS model was the best. As for the siPLS-GA-PLS model,5 6 characteristic wavelength points were chosen,the correlation coefficient (Rcal )and root mean square error(RMSEC)of calibration set was 0.96 and 0.043 respectively,and the correlation coefficient(Rp )and root mean square error(RMSEP)of prediction set was 0.96 and 0.048 respectively.Spectral variables were reduced and model accu-racy was improved.It can be concluded that characteristic bands selection and rapid and accurate detection of lamb pH can be achieved using hyperspectral imaging technique combined with siPLS-GA method.%波段筛选方法的选取以及随后的光谱特征波段的提取对高光谱模型效果的影响较大。为了快速准确检测羊肉的 pH 值,开展并讨论了利用两种特征波段筛选方法对羊肉 pH 值高光谱模型的影响研究。本研究采用二阶导数(2D)、多元散射校正(MSC)和中心化处理(mean-centering)相结合的方法对所提取纯肌肉部分的代表性光谱进行预处理,利用联合区间

  6. Development of an accurate pH measurement methodology for the pore fluids of low pH cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, M. C.; Garcia Calvo, J. L. [The Spanish National Research Council (CSIC), Madrid (Spain); Walker, C. [Japan Atomic Energy Agency (JAEA), Ibaraki (Japan)] [and others

    2012-08-15

    The main objective of this project has been the development of an agreed set of protocols for the pH measurement of the pore fluid of a low pH cementitious material. Three protocols have been developed (Chapter 2), a reference method, based on pore fluid expression (PFE), and two routine methods with and without filtering, based on Ex Situ Leaching (ESL) procedures. Templates have been designed on which to record details of the pH measurement for the reference (PFE) method (Appendix C) and the routine (ESL) methods without and with filtering (Appendix D). Preliminary protocols were based on a broad review of the literature (Appendix A) and refined through a series of test experiments of the more critical parameters (Appendix B). After definition of the preliminary protocols, two phases of interlaboratory tests were performed. The first phase (Chapter 3) used the same low pH cement paste and enabled the nine participating laboratories to use, become familiar with and to identify any problems/uncertainties in the preliminary protocols. The reported pH values were subjected to a statistical analysis of the (within laboratory) repeatability and (between-laboratory) reproducibility and so provided a reliability test of the preliminary protocols. The second phase (Chapter 4) of interlaboratory tests used four different candidate low pH cementitious materials in the same nine laboratories, which allowed testing, validation and comparison of the reported pH values, which were obtained using the final protocols for the reference (PFE) and routine (ESL) methods by statistical analysis. The proposed final protocols (Chapter 2) have resulted in the reported pH values having low deviation and high reproducibility and repeatability. This will allow confidence in the pH value when selecting a candidate low pH cementitious material to be used in the engineered component of a high-level nuclear waste repository.

  7. pH dependency of hydrogen fermentation from alkali-pretreated sludge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Batch tests were carried out to study the possibility of hydrogen production from alkali-pre- treated sludge without seed and the pH dependency of hydrogen fermentation from alkali-pretreated sludge. Experimental results showed that the sewage sludge with alkali-pretreatment could be successfully applied to biologically producing hydrogen without seed and extra-feed. The results also showed that the initial pH value of sewage sludge was an important factor throughout the hydrogen fermentation of alkali-pretreated sludge. The maximum hydrogen yield was obtained at initial pH value of 11.0 (14.4 mL·g VS-1). The hydrogen yield of alkali-pretreated sludge at alkaline initial pH value was much higher than that of acidic or neutral initial pH value. The optimal pH value of hydrogen production from alkali- pretreated sludge was approximately 9.5. The consumption of hydrogen could be inhibited when the pH value of sludge was above 8.5. The change of hydrogen yield at various initial pH values was similar to that of sludge SCOD. The change of sludge pH value was slow and acetate was the major component of volatile fatty acids produced in the process of hydrogen production. The yield and the constitution of volatile fatty acids were sensitive to the initial pH value.

  8. Neuronal pH regulation

    DEFF Research Database (Denmark)

    Vorstrup, S; Jensen, K E; Thomsen, C

    1989-01-01

    The intracellular pH in the brain was studied in six healthy volunteers before and immediately after the administration of 2 g of acetazolamide. Phosphorus-31 nuclear magnetic resonance spectroscopy by a 1.5 tesla whole-body scanner was used. The chemical shift between the inorganic phosphate...... and the phosphocreatine resonance frequencies was used for indirect assessment of the intracellular pH. The mean baseline intracellular pH was 7.05 +/- 0.04 (SD). The mean pH changes obtained at 15-min intervals within the first hour of acetazolamide administration were -0.03 +/- 0.04 (SD), -0.02 +/- 0.03 (SD), and 0.......00 +/- 0.04 (SD), i.e., no statistically significant pH decrease was observed during the period where extracellular pH is known to drop markedly. Although several factors contribute to the lack of change of the intraneuronal pH, we will discuss that this observation in addition might suggest a direct...

  9. Impact of pH on Microbial Biomass Carbon and Microbial Biomass Phosphorus in Red Soils

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo-Chao; HE Zhen-Li; WANG Yi-Jun

    2004-01-01

    The impact of pH changes on microbial biomass carbon (Cmic) and microbial biomass phosphorus (Pmic)were examined for 3 red soils under citrus production with different lengths of cultivation. Soil pH significantly affected Cmic and Pmic. The Cmic and Pmic changes, as a function of soil pH, appeared to follow a normal distribution with the original soil pH value at the apex and as pH increased or decreased compared to the original soil pH, Cmic and Pmic declined. Moreover, there were critical pH values at both extremes (3.0 on the acidic side and 8.0 to 8.5 on the alkaline side), beyond which most of microorganisms could never survive.The effect of pH on Cmic and Pmic was also related to the original soil pH. The higher the original soil pH was, the less Cmic or Pmic were affected by pH change. It is suggested that soil microorganisms that grow in a soil environment with a more neutral soil pH range (I.e. pH 5.5-7.5) may have a greater tolerance to pH changes than those growing in more acidic or more alkaline soil pH conditions.

  10. PhEDEx Data Service

    Science.gov (United States)

    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.

  11. Programmable pH buffers

    Energy Technology Data Exchange (ETDEWEB)

    Gough, Dara Van; Huber, Dale L.; Bunker, Bruce C.; Roberts, Mark E.

    2017-01-24

    A programmable pH buffer comprises a copolymer that changes pK.sub.a at a lower critical solution temperature (LCST) in water. The copolymer comprises a thermally programmable polymer that undergoes a hydrophobic-to-hydrophilic phase change at the LCST and an electrolytic polymer that exhibits acid-base properties that are responsive to the phase change. The programmable pH buffer can be used to sequester CO.sub.2 into water.

  12. PhEDEx Data Service

    Energy Technology Data Exchange (ETDEWEB)

    Egeland, Ricky [University of Minnesota, Twin Cities (United States); Wildish, Tony [Princeton University (United States); Huang, Chih-Hao [Fermi National Accelerator Laboratory (United States)

    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.

  13. 益生菌Lactobacillus casei Zhang在酸胁迫下的蛋白质组学研究%Proteomics Researches on Acid Response of Lactobacillus casei Zhang Grown at Different pH Values Using Two-Dimensional Gel Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    乌日娜; 岳喜庆; 张和平

    2012-01-01

    Lactobacilluscasei Zhang是1株筛选自发酵酸马奶,并具有耐酸等益生特性的益生乳杆菌。该研究利用蛋白质组双向电泳,比较了其在pH值为7.0和5.5的培养液中分别生长至对数生长期中期的蛋白质组表达差异。结果表明,有11个蛋白质点表达发生明显变化,经过基质辅助激光解吸/电离飞行时间质谱鉴定,其中有3个表达增强的蛋白质点分别鉴定为翻译因子(EF-Tu),N-乙酰氨基葡萄糖-6-磷酸脱醛酶(NagA)和小热休克蛋白(sHsp)。酸胁迫可诱导乳酸菌产生复杂的酸应激反应,涉及不同的代谢调控途径。%Lactobacillus casei Zhang, isolated from traditional home-made koumiss in Inner Mongolia of China, has been considered as a new probiotic bacterium for its characteristics, especially acid tolerance. Proteomics resear- ches were carried out to identify proteins expression of Lactobacillus casei Zhang grown at different pH values of pH 7.0 and 5.5. Cytosolic proteins of mid-exponential phase were resolved and further analyzed by two-dimensional gel electrophoresis. As results shown, eleven protein spots were found showing statistically significant differences. Three of total protein spots were identified as EF-Tu, NagA and sHsp using matrix-assisted laser desorption/ionization time- of-flight mass spectrometry (MALDI-TOF/MS) , indicating the complex response of lactic acid bacteria to acid stress.

  14. Reversion of Anode Characteristics of Galvanizing Coating in Simulated Concrete Pore Solution with Different pH Values%不同pH值模拟混凝土孔隙液中镀锌层的阳极特性逆转

    Institute of Scientific and Technical Information of China (English)

    余长春; 游革新; 王剑; 骆朋华; 刘钧泉

    2013-01-01

    在不同pH值的混凝土中镀锌层显示有阳极逆转现象,其对基体钢的保护作用出现变化.以回填海沙导致近海陆地混凝土建筑镀锌钢管的局部腐蚀为例,模拟其实际工况,将镀锌试样置于6种不同的模拟混凝土孔隙液中,将去锌层钢基置于3.5%NaCl中性溶液中浸泡24h,用盐桥连接电解池,测定2种试样间的电位-时间曲线和电偶电流值,并与无预浸泡的相应值对比.结果表明:(1)当镀锌层在含有Cl-的中性溶液及pH =10.0,11.0的Ca(OH)2溶液中时,对钢基体起到了牺牲阳极的保护作用;(2)当镀锌层在pH=12.0的Ca(OH)2溶液中时,无论是否预浸泡其电位均出现逆转现象,且电偶电流值为正值,反而会促进钢基体的腐蚀;(3)在pH =12.5的Ca(OH)2溶液中,无预浸泡时镀锌层对去锌层钢基有保护作用,预浸泡24h后初始阶段具有保护作用,1 650 s后时出现逆转,不仅已失去对钢基体的保护作用,反而会加速其腐蚀.%The backfill of the sand from the sea causes the local corrosion of galvanized steel pipes used in concrete -based buildings near the coast. Galvanized specimens were immersed into 6 kinds of simulated concrete pore solution with different values, while the steel substrate without galvanizing coating was immersed in the aqueous solution of 3. 5%NaCl for 24 h. After the electrolysis cell was linked with an electrolytic bridge, the potential-time curves between the two kinds of specimens as well as the current of the galvanic couple were measured and compared with those in the absence of pre-immersion. It was found that, in neutral solution containing Cl- and saturated Ca(OH)2 solution with pH = 10.0, 11.0, the galvanizing coating acted as a sacrificial anode to well protect the steel substrate. However, in saturated Ca( OH) 2 solution with pH = 12.0, whether the galvanizing coating was pre-immersed or not, its potential tended to reverse and relevant galvanic couple current was positive

  15. Modelling the effect of pH on the colour degradation of blanched broccoli

    NARCIS (Netherlands)

    Tijskens, L.M.M.; Barringer, S.A.; Biekman, E.S.A.

    2001-01-01

    In ready-to-eat salads, a low pH is often applied in the salad dressing. The effect of pH on the colour change of blanched-frozen-and-thawed broccoli was studied. Different acids were used to achieve the pH values in buffer solutions. A model on chlorophyll degradation in fruits and vegetables was

  16. A Self-Powered Triboelectric Nanosensor for PH Detection

    Directory of Open Access Journals (Sweden)

    Ying Wu

    2016-01-01

    Full Text Available A self-powered, sliding electrification based triboelectric sensor was developed for detecting PH value from a periodic contact/separation motion. This innovative, cost-effective, simply designed sensor is composed of a fluorinated ethylene propylene thin film and an array of electrodes underneath. The operation of the TENG (triboelectric nanogenerator sensor relies on a repetitive emerging-submerging process with traveling solution waves, in which the coupling between triboelectrification and electrostatic induction gives rise to alternating flows of electrons between electrodes. On the basis of coupling effect between triboelectrification and electrostatic induction, the sensor generates electric output signals which are associated with PH value. Experimental results show that the output voltage of the TENG sensor increases with the increasing PH value, which indicate that the PH value of different solution can be real-time monitored. This work not only demonstrates a new principle in the field of PH value measurement but also greatly expands the applicability of triboelectric nanogenerator (TENG as self-powered sensors.

  17. Effect of pH on biological phosphorus uptake.

    Science.gov (United States)

    Serralta, J; Ferrer, J; Borrás, L; Seco, A

    2006-12-05

    An anaerobic aerobic laboratory scale sequencing batch reactor (SBR) was operated to study the effect of pH on enhanced biological phosphorus removal. Seven steady states were achieved under different operating conditions. In all of them, a slight variation in the pH value was observed during anaerobic phase. However, pH rose significantly during aerobic phase. The increase observed was due to phosphorus uptake and carbon dioxide stripping. When pH was higher than 8.2-8.25 the phosphorus uptake rate clearly decreased. The capability of Activated Sludge Model No. 2d (ASM2d) and Biological Nutrient Removal Model No. 1 (BNRM1) to simulate experimental results was evaluated. Both models successfully characterized the enhanced biological phosphorus removal performance of the SBR. Furthermore, BNRM1 also reproduced the pH variations observed and the decrease in the phosphorus uptake rate. This model includes a switch function in the kinetic expressions to represent the pH inhibition in biological processes. The pH inhibition constants related to polyphosphate storage process were obtained by adjusting model predictions to measured phosphorus concentrations. On the other hand, pH inhibition should be included in ASM2d to accurately simulate experimental phosphorus evolution observed in an A/O SBR.

  18. Understanding thermostability and pH dependent properties of proteins

    DEFF Research Database (Denmark)

    Galberg, Pernille

    , which could be used for predicting mutations with expectation of increased thermostability at a certain pH value or a shifted pH activity optimum. The ability of a Bacillus circulans xylanase (BCX) mutant (N35D/A115E) to induce a decrease in pH activity optimum was evaluated by a pH dependent xylanase...... activity study and compared to wild type (WT). BCX N35D/A115E was created by site-directed mutagenesis followed by expression and purification. The kinetic characterization for BCX WT and N35D/A115E protein were determined as a function of pH using o-nitrophenyl-β-D-xylobioside as a substrate. The N35D....../A115E substitutions caused a 1.4 pH unit decrease in the pH activity optimum but the overall activity of the mutant was reduced by approximately 75 % compared to WT protein at their respective pH optima. Additionally BCX was used as a model for evaluating PROPKA. Six designed mutants were generated...

  19. The current status of intrapartum continuous fetal tissue pH measurements

    DEFF Research Database (Denmark)

    1991-01-01

    Continuous tissue pH monitoring during labor has now been possible for 15 years. Tissue pH is measured in the intercellular fluid, and the value differs in some cases from the blood pH value because of local capillary flow and local metabolism. The fetal scalp seems to be an area where tissue pH...... and capillary blood pH values are very close, but in acute acidosis there may be a time lag of 10-15 min before tissue pH is equilibrated. Normal values of scalp tissue pH are 7.38 in early labor declining by 0.016 per hour during the first stage of labor and by 0.12 per hour during the second stage of labor....... Tissue pH values below 7.15 are defined as pathological. The correlation coefficient to umbilical artery blood pH (0.71), success rate (67%) and electrode drift (below 0.04) from the largest study of tissue pH monitoring using glass pH electrodes (n = 337) are described....

  20. pH值对共沉淀-水热法合成Pr-CeO2粉体性能的影响%EFFECT OF pH VALUE ON PROPERTIES OF Pr-CeO2 POWDER SYNTHESIZED BY CO-PRECIPITATION-HYDROTHERMAL METHOD

    Institute of Scientific and Technical Information of China (English)

    朱振峰; 贺睿华; 李静平; 李军奇

    2009-01-01

    以Ce(NO3)3·6H2O、Pr6O11为原料,聚乙二醇为表面分散剂,采用共沉淀剂-水热法制备了Pr-CeO2纳米粉体.采用X射线衍射仪、比色计、Raman光谱、透射电镜研究了不同pH值对粉体晶体结构、呈色性能和形貌的影响.结果表明:碱性水热环境下,Pr部分溶解于CeO2晶格,易生成分散性较好的小晶粒.酸性水热环境下,晶粒的发育更完善,晶粒尺寸变大.Pr在CeO2晶格中的溶解度增大,氧空穴浓度也增大.%Pr-CeO2 nano-powders were prepared by a co-precipitation-hydrothermal method, using Ce(NO3)3·6H2O, Pr6O11 as raw materials and polyethylene glycol(PEG) as additive. The influences of different pH value on the crystallite structure, coloring proper-ties, morphologies and the oxygen vacancies of powders were studied by using X-ray diffraction, colorimeter, laser Raman spectra and transmission electron microscopy. The results show that, in the alkaline hydrothermal medium, praseodymium dissolves partly into the crystal lattice of CeO2, and small crystallites with good dispersion are easily formed. In the acidic hydrothermal medium, the powders show morphologies with improved crystallization, and the crystallite sizes become larger. The solubility of praseodymium into the crystal lattice of CeO2 and the concentration of oxygen vacancies both increase.

  1. Public Values

    DEFF Research Database (Denmark)

    Beck Jørgensen, Torben; Rutgers, Mark R.

    2015-01-01

    administration is approached in terms of processes guided or restricted by public values and as public value creating: public management and public policy-making are both concerned with establishing, following and realizing public values. To study public values a broad perspective is needed. The article suggest......This article provides the introduction to a symposium on contemporary public values research. It is argued that the contribution to this symposium represent a Public Values Perspective, distinct from other specific lines of research that also use public value as a core concept. Public...... a research agenda for this encompasing kind of public values research. Finally the contributions to the symposium are introduced....

  2. Comparison of pH Data Measured with a pH Sensor Array Using Different Data Fusion Methods

    Directory of Open Access Journals (Sweden)

    Yi-Hung Liao

    2012-09-01

    Full Text Available This paper introduces different data fusion methods which are used for an electrochemical measurement using a sensor array. In this study, we used ruthenium dioxide sensing membrane pH electrodes to form a sensor array. The sensor array was used for detecting the pH values of grape wine, generic cola drink and bottled base water. The measured pH data were used for data fusion methods to increase the reliability of the measured results, and we also compared the fusion results with other different data fusion methods.

  3. Immobilized pH gradients (IPG) simulator--an additional step in pH gradient engineering: I. Linear pH gradients.

    Science.gov (United States)

    Tonani, C; Righetti, P G

    1991-12-01

    A new computer program, called immobilized pH gradients (IPG) simulator, is proposed for calculating and optimizing any recipe for use in isoelectric focusing in immobilized pH gradients. Unlike our previous monoprotic electrolyte gradient simulation (MGS) and polyelectrolyte gradient simulation (PGS) programs, based on minimizing CV(beta), the present program has a target function the minimization of the quadratic moment around zero of the residuals (mu 2). With this algorithm it is possible to formulate IPG recipes which have deviations from linearity well below 1% of the given pH interval (a limit set with the previous MGS and PGS programs), in fact, as small as 0.1-0.2% (in pH units). The new simulator performs 2-3 times better than the previous ones in the pH 4-10 range, and is absolutely necessary when working outside this range, at extreme pH values, where CV(beta) cannot work against the buffering power of bulk water, thus generating pH recipes with huge deviations from linearity. In the latter cases, mu 2 performs 10 times better than CV(beta). When utilizing strong titrants for extended pH intervals, the "all or none" rule has been discovered: such titrants should always be used in tandem, since omission of one of the two at either the acidic or basic extremes produces strongly distorted pH profiles. Our new, most powerful simulator also contains equations for creating nonlinear gradients, notably: concave and convex exponentials and sigmoidal (see the companion paper: Righetti, P. G. and Tonani, C., Electrophoresis 1991, 12, 1021-1027).

  4. SON 68 nuclear glass alteration kinetics between pH 7 and pH 11.5

    Science.gov (United States)

    Gin, S.; Mestre, J. P.

    2001-05-01

    The effect of the pH was investigated on the mechanisms of SON 68 (R7T7-type) glass alteration under `saturation' conditions in order to delimit the pH range within which a stable, protective gel is formed. Static experiments were conducted at 90°C with an S/ V ratio of 50 cm-1 at various imposed pH values: 7, 8, 9.5, 10, 10.5, 11 and 11.5. An additional experiment was conducted with no restriction on the pH. The kinetic study showed that a protective gel formed in all the test media, although its stability was pH-dependent: at pH 11 or higher, the precipitation of a potassium and sodium aluminosilicate led to the degradation of the gel and the lose of its protective properties. This phenomenon resulted in renewed glass alteration, leading to complete and rapid degradation of the glass into alteration products. The aluminosilicate precipitation was found to be limited by the solubility of aluminum. Below pH 10, this type of secondary phase is unlikely to precipitate and the gel should remain stable. This study, based on thermodynamic and kinetic considerations, suggests that aqueous alteration of the French SON 68 nuclear glass results in the formation of a protective gel with long-term stability between pH 7 and pH 10.

  5. Acid skim milk gels: The gelation process as affected by preheated pH

    NARCIS (Netherlands)

    Lakemond, C.M.M.; Vliet, van T.

    2008-01-01

    The effect of preheating milk (10 min 80 [degree sign]C) at pH values from 6.20 to 6.90 on formation of acid skim milk gels was studied by dynamic oscillation measurements. Up to pH 6.65 a higher pH of heating (pHheating) resulted in a higher G'. Since below pH 4.9 the development of G'(pH)/G'(pH=4.

  6. In-situ pH Measurement at the Electrode/Solution Interface

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper a pH microprobe technique was developed to measure in-situ the pH value at the electrode/solution interface. Iridium oxide was used as a pH sensitive material with good response behavior in the measured solutions. The experimental results indicated that the interfacial pH increased with the applied potential, first jumped to a maximum, then slowly decreased at the controlled potential during the electrodeposition process of functional ceramics.

  7. Titratable acidity of beverages influences salivary pH recovery

    Directory of Open Access Journals (Sweden)

    Livia Maria Andaló TENUTA

    2015-01-01

    Full Text Available A low pH and a high titratable acidity of juices and cola-based beverages are relevant factors that contribute to dental erosion, but the relative importance of these properties to maintain salivary pH at demineralizing levels for long periods of time after drinking is unknown. In this crossover study conducted in vivo, orange juice, a cola-based soft drink, and a 10% sucrose solution (negative control were tested. These drinks differ in terms of their pH (3.5 ± 0.04, 2.5 ± 0.05, and 5.9 ± 0.1, respectively and titratable acidity (3.17 ± 0.06, 0.57 ± 0.04 and < 0.005 mmols OH- to reach pH 5.5, respectively. Eight volunteers with a normal salivary flow rate and buffering capacity kept 15 mL of each beverage in their mouth for 10 s, expectorated it, and their saliva was collected after 15, 30, 45, 60, 90, and 120 s. The salivary pH, determined using a mini pH electrode, returned to the baseline value at 30 s after expectoration of the cola-based soft drink, but only at 90 s after expectoration of the orange juice. The salivary pH increased to greater than 5.5 at 15 s after expectoration of the cola drink and at 30 s after expectoration of the orange juice. These findings suggest that the titratable acidity of a beverage influences salivary pH values after drinking acidic beverages more than the beverage pH.

  8. Titratable acidity of beverages influences salivary pH recovery.

    Science.gov (United States)

    Tenuta, Livia Maria Andaló; Fernández, Constanza Estefany; Brandão, Ana Carolina Siqueira; Cury, Jaime Aparecido

    2015-01-01

    A low pH and a high titratable acidity of juices and cola-based beverages are relevant factors that contribute to dental erosion, but the relative importance of these properties to maintain salivary pH at demineralizing levels for long periods of time after drinking is unknown. In this crossover study conducted in vivo, orange juice, a cola-based soft drink, and a 10% sucrose solution (negative control) were tested. These drinks differ in terms of their pH (3.5 ± 0.04, 2.5 ± 0.05, and 5.9 ± 0.1, respectively) and titratable acidity (3.17 ± 0.06, 0.57 ± 0.04 and pH 5.5, respectively). Eight volunteers with a normal salivary flow rate and buffering capacity kept 15 mL of each beverage in their mouth for 10 s, expectorated it, and their saliva was collected after 15, 30, 45, 60, 90, and 120 s. The salivary pH, determined using a mini pH electrode, returned to the baseline value at 30 s after expectoration of the cola-based soft drink, but only at 90 s after expectoration of the orange juice. The salivary pH increased to greater than 5.5 at 15 s after expectoration of the cola drink and at 30 s after expectoration of the orange juice. These findings suggest that the titratable acidity of a beverage influences salivary pH values after drinking acidic beverages more than the beverage pH.

  9. The pH dependent Raman spectroscopic study of caffeine

    Science.gov (United States)

    Kang, Jian; Gu, Huaimin; Zhong, Liang; Hu, Yongjun; Liu, Fang

    2011-02-01

    First of all the surface enhanced Raman spectroscopy (SERS) and normal Raman spectra of caffeine aqueous solution were obtained at different pH values. In order to obtain the detailed vibrational assignments of the Raman spectroscopy, the geometry of caffeine molecule was optimized by density functional theory (DFT) calculation. By comparing the SERS of caffeine with its normal spectra at different pH values; it is concluded that pH value can dramatically affect the SERS of caffeine, but barely affect the normal Raman spectrum of caffeine aqueous solution. It can essentially affect the reorientation of caffeine molecule to the Ag colloid surface, but cannot impact the vibration of functional groups and chemical bonds in caffeine molecule.

  10. Data on soil PH of Barddhaman district, India

    Directory of Open Access Journals (Sweden)

    Sumanta Bid

    2017-06-01

    Full Text Available PH (Puissance de Hydrogen is an essential ingredient of soil that effects on fertility and productivity of dirt. Barddhaman district is a part of Lower Gangetic Plain fully covered by alluvial soil and popularly known as ‘rice bowl of West Bengal’ owing to its lofty production. This data article provides a block level data on soil PH that is essential for further investigation of the relationship among soil ph, plant growth, plant health and productivity. This data is valuable in the field of soil geography and soil science. Soil PH data is more relevant in the ground of plant biology, agricultural geography and agricultural science. It helps to explain the acidic and alkaline nature of alluvial soil. The data consist of 195 samples (n=195 taken from the entire district. Samples have been collected from March, 2014 to March, 2015 and experimented in the laboratory. Theoretically PH value is limited within 0–14. Experiment result exemplifies the highest value 8.5 found in Khandaghosh block whereas lowest value is 4.5 and the samples which result in lowest value are gathered from 4 different blocks like Manteswar, Burdwan - II, Barabani and Salanpur.

  11. PhEDEx Data Service

    CERN Document Server

    Egeland, Ricky; Huang, Chih-Hao

    2009-01-01

    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,...

  12. pH in Action

    NARCIS (Netherlands)

    Tijskens, L.M.M.; Biekman, E.S.A.

    2001-01-01

    Based on fundamental chemical relations, well-established in chemical engineering and chemical technology over almost a century, the effects of pH in food and agricultural products will be deduced for different situations and processes. Based on simple equilibria and dissociation of water, salts, ac

  13. Plant based dietary supplement increases urinary pH

    Directory of Open Access Journals (Sweden)

    Rao A Venket

    2008-11-01

    Full Text Available Abstract Background Research has demonstrated that the net acid load of the typical Western diet has the potential to influence many aspects of human health, including osteoporosis risk/progression; obesity; cardiovascular disease risk/progression; and overall well-being. As urinary pH provides a reliable surrogate measure for dietary acid load, this study examined whether a plant-based dietary supplement, one marketed to increase alkalinity, impacts urinary pH as advertised. Methods Using pH test strips, the urinary pH of 34 healthy men and women (33.9 +/- 1.57 y, 79.3 +/- 3.1 kg was measured for seven days to establish a baseline urinary pH without supplementation. After this initial baseline period, urinary pH was measured for an additional 14 days while participants ingested the plant-based nutritional supplement. At the end of the investigation, pH values at baseline and during the treatment period were compared to determine the efficacy of the supplement. Results Mean urinary pH statistically increased (p = 0.03 with the plant-based dietary supplement. Mean urinary pH was 6.07 +/- 0.04 during the baseline period and increased to 6.21 +/- 0.03 during the first week of treatment and to 6.27 +/- 0.06 during the second week of treatment. Conclusion Supplementation with a plant-based dietary product for at least seven days increases urinary pH, potentially increasing the alkalinity of the body.

  14. 不同pH值下胞外聚合物对污泥脱水性能及束缚水含量的影响%Influence of extracellular polymeric substances on sludge dewaterability and bound water content at various pH values

    Institute of Scientific and Technical Information of China (English)

    邢奕; 王志强; 洪晨; 司艳晓; 张坤; 刘敏; 田星强; 李洋

    2015-01-01

    The changes of sludge dewaterability and bound water content at various pH values were investigated in this study. The protein and polysaccharide contents in each layer of extracellular polymeric substances ( S-EPS、LB-EPS and TB-EPS) and the organic acid and organic functional group contents in S-EPS were determined in an attempt to explain the influence of EPS on the sludge dewa-terability and bound water content. The results indicate that the sludge dewaterability under acidic conditions is obviously better than that under neutral conditions, and the water content of dewatered sludge ( WC) and the capillary suction time ( CST) can be decreased to 60. 8% and 25. 4 s at pH 3. 03, respectively. Under alkaline conditions, the bound water content in dewatered sludge, the WC and CST significantly increase, and the sludge dewaterability deteriorates. The addition of acid or alkali reduces TB-EPS, on the contrary, increases LB-EPS and S-EPS. Each layer of extracellular polymeric substances has significant correlation with the WC, CST and the bound water content, and S-EPS has most significant correlation with the sludge dewaterability and bound water content. In the process of acid-alkali conditioning, the amount and type of organic-functional groups improve obviously and hydrolysis of partly EPS generates organic acids and other small molecules.%研究了不同pH值下污泥脱水性能和束缚水含量的变化,通过测定污泥调理过程中各层胞外聚合物( S-EPS、LB-EPS和TB-EPS)中蛋白质和多糖的含量、S-EPS中有机官能团以及有机酸的含量,探讨了胞外聚合物对污泥脱水性能及束缚水含量的影响.酸性条件下,污泥的脱水性能明显好于中性条件,并且pH值为3.03时,污泥滤饼含水率( WC)和毛细吸水时间( CST)均降至最低,分别为60.8%和25.4 s;碱性条件下,污泥中束缚水的含量明显增加,WC和CST均大幅升高,污泥脱水性能恶化.酸碱的加入导致污泥中TB-EPS含量降

  15. A strategy for selecting the pH of protein solutions to enhance crystallization.

    Science.gov (United States)

    Zhang, Chen Yan; Wu, Zi Qing; Yin, Da Chuan; Zhou, Bo Ru; Guo, Yun Zhu; Lu, Hui Meng; Zhou, Ren Bin; Shang, Peng

    2013-07-01

    The pH of a solution is an important parameter in crystallization that needs to be controlled in order to ensure success. The actual pH of the crystallization droplet is determined by the combined contribution of the buffers in the screening and protein solutions, although the contribution of the latter to the pH is often ignored. In this study, the effects of the buffer and protein solution pH values on the results of screening are systematically investigated. It was found that these parameters significantly affected the results and thus the following strategy for the selection of appropriate pH values is proposed: (i) when screening with only one protein solution, the pH should be as low, as high or as divergent from the pI as possible for a basic, acidic or neutral protein, respectively, within its stable pH range; (ii) when screening with two protein solutions, the pH values should be well separated from one another; and (iii) when multiple pH values are utilized, an even distribution of pH values is the best approach to increase the success rate of crystallization.

  16. Consideration of factors affecting strip effluent pH and sodium content

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-07-29

    A number of factors were investigated to determine possible reasons for why the Strip Effluent (SE) can sometimes have higher than expected pH values and/or sodium content, both of which have prescribed limits. All of the factors likely have some impact on the pH values and Na content.

  17. Consideration of factors affecting strip effluent pH and sodium content

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-07-29

    A number of factors were investigated to determine possible reasons for why the Strip Effluent (SE) can sometimes have higher than expected pH values and/or sodium content, both of which have prescribed limits. All of the factors likely have some impact on the pH values and Na content.

  18. Values Research

    Science.gov (United States)

    2009-10-01

    horizontal vs. vertical. • According to the theory of Planned Behavior ( Ajzen , 1988, 2002) attitude, subjective norms and perceived control...determines intention which may end in behavior . 7 Defining Human Values Cross-cultural theories on values emerged in the 80s developed by three main...attitudes with social structure. 4 Defining Human Values • According to Parsons (Parsons & Shils, 1951), values instigate behavior . • In line

  19. Industrial PhD report: Sustainable Innovation

    DEFF Research Database (Denmark)

    Olesen, Gitte Gylling Hammershøj

    2011-01-01

    Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....

  20. Industrial PhD report: Sustainable Innovation

    DEFF Research Database (Denmark)

    Olesen, Gitte Gylling Hammershøj

    2011-01-01

    Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....

  1. A survey of beef muscle color and pH.

    Science.gov (United States)

    Page, J K; Wulf, D M; Schwotzer, T R

    2001-03-01

    The objectives of this study were to define a beef carcass population in terms of muscle color, ultimate pH, and electrical impedance; to determine the relationships among color, pH, and impedance and with other carcasses characteristics; and to determine the effect of packing plant, breed type, and sex class on these variables. One thousand beef carcasses were selected at three packing plants to match the breed type, sex class, marbling score, dark-cutting discount, overall maturity, carcass weight, and yield grade distributions reported for the U.S. beef carcass population by the 1995 National Beef Quality Audit. Data collected on these carcasses included USDA quality and yield grade data and measurements of muscle color (L*, a*, b*), muscle pH, and electrical impedance of the longissimus muscle. About one-half (53.1%) of the carcasses fell within a muscle pH range of 5.40 to 5.49, and 81.3% of the carcasses fell within a longissimus muscle pH range of 5.40 to 5.59. A longissimus muscle pH of 5.87 was the approximate cut-off between normal and dark-cutting carcasses. Frequency distributions indicated that L* values were normally distributed, whereas a* and b* values were abnormally distributed (skewed because of a longer tail for lower values, a tail corresponding with dark-cutting carcasses). Electrical impedance was highly variable among carcasses but was not highly related to any other variable measured. Color measurements (L*, a*, b*) were correlated (P Brahman-type (pH = 5.46, L* = 39.75, a* = 25.17, and b* = 11.05) carcasses (P < 0.05).

  2. pH Responsiveness of hydrogels formed by telechelic polyampholytes.

    Science.gov (United States)

    Dyakonova, Margarita A; Gotzamanis, George; Niebuur, Bart-Jan; Vishnevetskaya, Natalya S; Raftopoulos, Konstantinos N; Di, Zhenyu; Filippov, Sergey K; Tsitsilianis, Constantinos; Papadakis, Christine M

    2017-05-21

    We investigate the influence of pH on the rheological and structural properties of hydrogels formed by hydrophobic association of the sticky ends of the triblock terpolymer poly(methyl methacrylate)-b-poly(2-(diethylamino)ethyl methacrylate-co-methacrylic acid)-b-poly(methyl methacrylate) (PMMA-b-P(DEA-co-MAA)-b-PMMA). The middle block is a weak polyampholyte having a pH dependent charge density and sign, which enables tuning of the rheological and structural properties by pH variation. Small-angle neutron scattering (SANS) studies of solutions in D2O at 0.05 wt% and pH 3.0 reveal clusters of interconnected spherical micelles having PMMA cores, stabilized by repulsive ionic interactions in the middle polyampholyte block. With increasing pH, the degree of ionization of the DEA units decreases, whereas the one of the MAA units increases, resulting in a complete loss of the correlation between these micelles. At a concentration of 3 wt% at low pH values, the system forms a gel with charged fuzzy spheres from PMMA interacting via a screened Coulomb potential. With increasing pH, the gel disintegrates due to the decrease in the effective charge on the micelles. At both concentrations, the hydrophobic aggregation of micelles is observed near the isoelectric point. At pH 3.0-7.4, the autocorrelation functions measured by rotational dynamic light scattering at 3 wt% exhibit a decay steeper than single exponential, which confirms that the gels are frozen, presumably due to the glassy PMMA cores and hydrophobic interpolyelectrolyte complexes. At pH 11, the diffusion of single micelles is observed in addition to the frozen dynamics.

  3. Critical assessment of the pH of children's soap

    Directory of Open Access Journals (Sweden)

    Bruna Rafaela Mendes

    2016-06-01

    Full Text Available Abstract Objective: To evaluate the pH value of children's antibacterial soaps and syndets used in children's baths and verify whether there is information regarding pH on the product label. Methods: Quantitative, cross-sectional, analytical observational study that included ninety soap samples, both in bar and liquid presentations, as follows: 67 children's soap (group 1, 17 antibacterial soaps (group 2, and 6 syndets (group 3. Each sample had its pH measured after 1% dilution. In addition to descriptive statistics, the Pearson-Yates chi-squared test and Student's t-tests were applied, considering the minimal significance level of 5%. The Wilcoxon-Mann-Whitney test, Fisher's exact test, and the Kruskal-Wallis test were used for inferential statistics. Results: The pH levels varied considerably between liquid and bar presentations, with lower levels (4.4-7.9 found for the liquids (p < 0.05. Syndets showed pH levels close to the ideal (slightly acid and the antibacterial soaps showed the highest pH levels (up to 11.34 (p < 0.05. Only two of the soaps included in the study had information about their pH levels on the product packaging. Conclusions: Knowledge of the pH of children's soap by doctors and users is important, considering the great pH variability found in this study. Moreover, liquid soaps, and especially syndets, are the most recommended for the sensitive skin of neonates and infants, in order to guarantee skin barrier efficacy.

  4. pH measurement and a rational and practical pH control strategy for high throughput cell culture system.

    Science.gov (United States)

    Zhou, Haiying; Purdie, Jennifer; Wang, Tongtong; Ouyang, Anli

    2010-01-01

    The number of therapeutic proteins produced by cell culture in the pharmaceutical industry continues to increase. During the early stages of manufacturing process development, hundreds of clones and various cell culture conditions are evaluated to develop a robust process to identify and select cell lines with high productivity. It is highly desirable to establish a high throughput system to accelerate process development and reduce cost. Multiwell plates and shake flasks are widely used in the industry as the scale down model for large-scale bioreactors. However, one of the limitations of these two systems is the inability to measure and control pH in a high throughput manner. As pH is an important process parameter for cell culture, this could limit the applications of these scale down model vessels. An economical, rapid, and robust pH measurement method was developed at Eli Lilly and Company by employing SNARF-4F 5-(-and 6)-carboxylic acid. The method demonstrated the ability to measure the pH values of cell culture samples in a high throughput manner. Based upon the chemical equilibrium of CO(2), HCO(3)(-), and the buffer system, i.e., HEPES, we established a mathematical model to regulate pH in multiwell plates and shake flasks. The model calculates the required %CO(2) from the incubator and the amount of sodium bicarbonate to be added to adjust pH to a preset value. The model was validated by experimental data, and pH was accurately regulated by this method. The feasibility of studying the pH effect on cell culture in 96-well plates and shake flasks was also demonstrated in this study. This work shed light on mini-bioreactor scale down model construction and paved the way for cell culture process development to improve productivity or product quality using high throughput systems.

  5. Oxidation in fish oil enriched mayonnaise : Ascorbic acid and low pH increase oxidative deterioration

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Timm Heinrich, Maike; Meyer, Anne S.

    2001-01-01

    The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil- water interface into the aqueous phase at all pH levels......, but this effect of ascorbic acid was strongest at low pH (pH 3.8- 4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted...... due to the reduction of Fe3+ to Fe2+ that rapidly catalyzes lipid oxidation via lipid hydroperoxide decomposition at the oil-water interface in mayonnaise...

  6. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  7. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  8. Effect of pH on Paramagnetic Centers in Cladosporium cladosporioides Melanin

    Science.gov (United States)

    Pilawa, B.; Buszman, E.; Gondzik, A.; Wilczyński, S.; Zdybel, M.; Witoszyńska, T.; Wilczok, T.

    2006-07-01

    Paramagnetic centers in melanin existing in pigmented soil fungi Cladosporium cladosporioides cultured at acidic (4, 5, 6), neutral (7), and alkaline (8) pH were studied by EPR method. o-semiquinone free radicals (g: 2.0032-2.0040) concentration in melanin biopolymer increased for pH from 4 to 6, decreased at pH 7, and reached the maximum value at pH 8. It may be expected that melanin free radicals reactions with small molecules (metal ions, drugs) are the most effective at pH between 6 and 8. Slow spin-lattice relaxation processes exist in the all studied melanin samples.

  9. In situ measurements reveal extremely low pH in soil

    DEFF Research Database (Denmark)

    Nielsen, Knud Erik; Nielsen, Lars Peter; Damgaard, Christian Frølund

    2017-01-01

    We measured pH in situ in the top organic soil horizons in heathland and pine forest and found values between 2.6 and 3.2. This was 0.5e0.8 units lower than concurrent laboratory pH measurements of the same soil, which raises questions about the interpretation of pH measurements. We propose...... that the higher pH recorded by standard laboratory methods may be due to buffering ions from soil biota released from drying, grinding and rewetting of soil samples, whereas the in situ pH reflects the correct level of acidification....

  10. In vitro alkaline pH resistance of Enterococcus faecalis.

    Science.gov (United States)

    Weckwerth, Paulo Henrique; Zapata, Ronald Ordinola; Vivan, Rodrigo Ricci; Tanomaru Filho, Mário; Maliza, Amanda Garcia Alves; Duarte, Marco Antonio Hungaro

    2013-01-01

    Enterococcus faecalis is a bacterial species often found in root canals with failed endodontic treatment. Alkaline pastes are widely used in Endodontics because of their biocompatibility and antimicrobial activity, but this microorganism can resist alkalinity. The purpose of this study was to evaluate in vitro the alkaline pH resistance of E. faecalis for different periods up to 14 days. Samples were obtained from the oral cavity of 150 patients from the Endodontic clinic. The pH of the experimental tubes (n=84) was first adjusted with 6M NaOH to pH values of 9.5, 10.5, 11.5 and 12.5 (21 tubes per pH). Twenty clinical isolates and the ATCC 29212 strain were tested. The 5 positive controls and experimental tubes of each pH were inoculated with 10 µL of bacterial suspension and incubated at 36 °C for 24, 48 and 72 h, 7 and 14 days. For each period, the turbidity of the medium was visually compared with a 0.5 McFarland standard. The presence of the microorganism was confirmed by seeding on M-Enterococcus agar. Four tubes containing BHI broth adjusted to the tested pHs were incubated for 14 days to verify if pH changes occurred. The pH of inoculated BHI broth was also measured on day 14 to determine if the microorganism acidified the medium. The growth of all E. faecalis strains occurred at pH 9.5 to 11.5 in all periods. Although turbidity was not observed at pH 12.5, there was growth of 13 and 2 strains at 24 and 48 h, respectively, on M-Enterococcus agar. No tube showed growth at pH 12.5 after 72 h. It was concluded that E. faecalis can survive in highly alkaline pH, and some clinical isolates require 72 h at pH 12.5 to be killed.

  11. Effect of the Soil pH on the Alkaloid Content of Lupinus angustifolius

    OpenAIRE

    Gisela Jansen; Hans-Ulrich Jürgens; Edgar Schliephake; Frank Ordon

    2012-01-01

    Field studies were conducted in growing seasons 2004, 2005, and 2010 to investigate the effect of different soil pH values on the alkaloid content in seeds of Lupinus angustifolius. Two-year experiments with eleven cultivars were carried out in acid soils with an average of pH=5.8 (Mecklenburg-Western Pomerania) and on calcareous soils with an average pH of 7.1 (Bavaria), respectively. In addition, in 2010, eight cultivars were grown in field experiments in soils with pH values varying betwee...

  12. Effect of hydrogen peroxide with different pH values on the color, translucency and laser-induced fluorescence of human dentin%不同pH值过氧化氢对人牙本质颜色、透明度和激光诱导荧光的影响

    Institute of Scientific and Technical Information of China (English)

    梁珊珊; 蒋滔; 王贻宁

    2013-01-01

    Objective To investigate the effect of 30% hydrogen peroxide(HP) with different pH values on color,translucency and laser-induced fluorescence of human dentin.Methods Sixty dentin specimens from crown of mandibular third molars were randomly assigned into four groups (n =15) and treated with acidic 30% HP,neutral 30% HP,alkaline 30% HP and deionized water (control group),respectively.The bleaching process was 0.5 h × 4 times,and time points for measuring were baseline (0),0.5,1 and 2 h.A colorimeter was employed to measure the L *,a *,b * coordinates of dentin against white,black and yellow background.Then the parameters of translucency,masking effects,chroma and whiteness were calculated.The dentinal laser-induced Raman/fluorescence spectra was recorded by a Raman spectrometer and the fluorescence intensity (FI) and FI% were calculated.Results △FI of acidic,neutral,alkaline 30% HP at 2 h were 9960.03 ±2037.74,8502.09 ± 1413.86,8554.29 ± 1986.19.And △FI% were 84.60 ± 3.43,84.89 ± 5.19,86.72 ± 2.65,respectively.Repeated measure of ANOVA revealed that all parameters in the bleaching groups were significantly influenced by time (P < 0.001).Compared with control group,bleaching resulted significant change of △TP,△chroma,△ whiteness,△L*,△a*,△b*,△E,△FI and △FI% (P <0.001).There was no significant difference between three bleaching groups on △TP,△masking effects,△chroma,△whiteness,△L*,△b*,△E,△FI and △FI%.Correlation analysis demonstrated that FI was associated with chroma,a*,b* and whiteness,respectively,and △FI was associated with △TP,△masking effects,△whiteness,△chroma,△b* and △ E.Conclusions 30% HP with different pH values could result in the same change of the color,translucency and laser-induced fluorescence of human dentin.Laser-induced fluorescence was associated with dentinal color and translucency,which might be a novel way to investigate the bleaching mechanism of dentin

  13. Traceability of pH to the Mole

    Directory of Open Access Journals (Sweden)

    Maria Filomena Camões

    2015-08-01

    Full Text Available Free acidity of aqueous solutions was initially defined in 1909 by Søren Peter Lauritz Sørensen as pH = −lgcH+ (c/mol·dm−3 or m/mol·kg−1 of the free hydrogen ions in solution, H+ soon (1910 was changed to pH = paH+ = −lgaH+, integrating the new concepts of activity, ai and activity coefficient γi, for the ionic species i under concern, H+ in this case; it is ai = −lg(miγi. Since individual ions do not exist alone in solution, primary pH values cannot be assigned solely by experimental measurements, requiring extra thermodynamic model assumptions for the activity coefficient, γH+, which has put pH in a unique situation of not being fully traceable to the International System of Units (SI. Also the concept of activity is often not felt to be as perceptible as that of concentration which may present difficulties, namely with the interpretation of data. pH measurements on unknown samples rely on calibration of the measuring setup with adequate reference pH buffers. In this work, the assignment of pH values to buffers closely matching the samples, e.g., seawater, is revisited. An approach is presented to assess the quantity pmH+ = −lgmH+ profiting from the fact that, contrary to single ion activity coefficients, mean activity coefficients,   can be assessed based on experimentally assessed quantities alone, γExp ±, thus ensuring traceability to the mole, the SI base unit for amount of substance. Compatibility between γExp ± and mean activity coefficient calculated by means of Pitzer model equations, γPtz ±, validates the model for its intended use.

  14. The value of value congruence.

    Science.gov (United States)

    Edwards, Jeffrey R; Cable, Daniel M

    2009-05-01

    Research on value congruence has attempted to explain why value congruence leads to positive outcomes, but few of these explanations have been tested empirically. In this article, the authors develop and test a theoretical model that integrates 4 key explanations of value congruence effects, which are framed in terms of communication, predictability, interpersonal attraction, and trust. These constructs are used to explain the process by which value congruence relates to job satisfaction, organizational identification, and intent to stay in the organization, after taking psychological need fulfillment into account. Data from a heterogeneous sample of employees from 4 organizations indicate that the relationships that link individual and organizational values to outcomes are explained primarily by the trust that employees place in the organization and its members, followed by communication, and, to a lesser extent, interpersonal attraction. Polynomial regression analyses reveal that the relationships emanating from individual and organizational values often deviated from the idealized value congruence relationship that underlies previous theory and research. The authors' results also show that individual and organizational values exhibited small but significant relationships with job satisfaction and organizational identification that bypassed the mediators in their model, indicating that additional explanations of value congruence effects should be pursued in future research. (c) 2009 APA, all rights reserved.

  15. Raynaud-Phänomen

    Directory of Open Access Journals (Sweden)

    Sturm W

    2010-01-01

    Full Text Available Das Raynaud-Phänomen ist charakterisiert durch eine anfallsweise auftretende Minderdurchblutung und Verfärbung der Finger bedingt durch eine überschießende Vasokonstriktion der arteriellen Blutgefäße. Diese Veränderungen werden durch Kälte oder Stress ausgelöst und können ohne (primäre Form oder mit zugrundeliegenden Erkrankungen (sekundäre Form, häufig bei Sklerodermie, anderen Autoimmunerkrankungen oder Gefäßerkrankungen vorkommen. In der Diagnostik spielen Anamnese, physikalische Untersuchung, Laboruntersuchungen, Kapillarmikroskopie und Gefäßuntersuchungen mit Sonographie bzw. CT die wichtigste Rolle. In der Behandlung des Raynaud- Phänomens ist eine medikamentöse Therapie gerechtfertigt, wenn allgemeine Maßnahmen keine Besserung der Symptomatik bringen. Für Kalziumkanalblocker ist eine Wirksamkeit belegt, insbesondere für Nifedipin, das in seiner Retardform besonders geeignet erscheint. Bei schweren, insbesondere sekundären Formen von Raynaud mit ischämischen digitalen Ulzera, ist die Wirkung für Prostaglandine (besonders Iloprost und Endothelinantagonisten (Bosentan ausreichend belegt.

  16. MD-PhD training: looking back and looking forward.

    Science.gov (United States)

    Bonham, Ann C

    2014-01-01

    MD-PhD programs provide rigorous, integrated training for physician-scientists, enabling them to frame scientific questions in unique ways and to apply clinical insight to fundamental science. Few would question the influential contributions of MD-PhD physician-scientists in advancing medical science. In this issue of Academic Medicine, Jeffe et al affirm high levels of excellence in educational outcomes from MD-PhD training programs at U.S. MD-granting medical schools, especially programs that receive funding from the NIH Medical Scientist Training Program (MSTP). The author of this commentary observes that, in the face of current economic pressures, comprehensive, longitudinal national outcomes data from MSTP- and non-MSTP-funded MD-PhD programs will help verify the value provided by MD-PhD physician-scientists. She proposes that MD-PhD programs should better prepare the next generation of physician-scientists for future research environments, which will provide new technologies, venues, and modalities. These research environments will be more closely integrated within health care delivery systems, extend into diverse communities and regions, and employ complex technologies. MD-PhD physician-scientists also will train and gain expertise in broadening areas of research, such as health policy, health economics, clinical epidemiology, and medical informatics. Program leaders are ideally situated to foster innovative learning environments and methodologies. By sharing their innovations, they can help ensure production of a diverse MD-PhD physician-scientist workforce, prepared to engage in myriad research opportunities to meet patient and population needs in a new environment.

  17. Ratiometric imaging of extracellular pH in bacterial biofilms with C-SNARF-4.

    Science.gov (United States)

    Schlafer, Sebastian; Garcia, Javier E; Greve, Matilde; Raarup, Merete K; Nyvad, Bente; Dige, Irene

    2015-02-01

    pH in the extracellular matrix of bacterial biofilms is of central importance for microbial metabolism. Biofilms possess a complex three-dimensional architecture characterized by chemically different microenvironments in close proximity. For decades, pH measurements in biofilms have been limited to monitoring bulk pH with electrodes. Although pH microelectrodes with a better spatial resolution have been developed, they do not permit the monitoring of horizontal pH gradients in biofilms in real time. Quantitative fluorescence microscopy can overcome these problems, but none of the hitherto employed methods differentiated accurately between extracellular and intracellular microbial pH and visualized extracellular pH in all areas of the biofilms. Here, we developed a method to reliably monitor extracellular biofilm pH microscopically with the ratiometric pH-sensitive dye C-SNARF-4, choosing dental biofilms as an example. Fluorescent emissions of C-SNARF-4 can be used to calculate extracellular pH irrespective of the dye concentration. We showed that at pH values of biofilm and visualized the entire bacterial biomass in in vivo-grown dental biofilms with unknown species composition. We then employed digital image analysis to remove the bacterial biomass from the microscopic images and adequately calculate extracellular pH values. As a proof of concept, we monitored the extracellular pH drop in in vivo-grown dental biofilms fermenting glucose. The combination of pH ratiometry with C-SNARF-4 and digital image analysis allows the accurate monitoring of extracellular pH in bacterial biofilms in three dimensions in real time and represents a significant improvement to previously employed methods of biofilm pH measurement.

  18. Value Representations

    DEFF Research Database (Denmark)

    Rasmussen, Majken Kirkegaard; Petersen, Marianne Graves

    2011-01-01

    Stereotypic presumptions about gender affect the design process, both in relation to how users are understood and how products are designed. As a way to decrease the influence of stereotypic presumptions in design process, we propose not to disregard the aspect of gender in the design process......, as the perspective brings valuable insights on different approaches to technology, but instead to view gender through a value lens. Contributing to this perspective, we have developed Value Representations as a design-oriented instrument for staging a reflective dialogue with users. Value Representations...

  19. Acid loading test (pH)

    Science.gov (United States)

    ... 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 ...

  20. Fetal scalp pH testing

    Science.gov (United States)

    Fetal scalp blood; Scalp pH testing; Fetal blood testing - scalp; Fetal distress - fetal scalp testing; Labor - fetal scalp testing ... a baby. In these cases, testing the scalp pH can help the doctor decide whether the fetus ...

  1. Cadmium sorption in solution by a chitin: effect of pH; Sorption du cadmium en solution par une chitine: effet du pH

    Energy Technology Data Exchange (ETDEWEB)

    Benguella, B.; Benaissa, H. [Universtie de Tlemcen, Lab. de Materiaux Sorbants et Traitement des Eaux, Dept. de Chimie, Faculte des Sciences, Tlemcen (Algeria)

    2001-07-01

    The pH is an essential factor to take into consideration in the sorption mechanisms of metals: it acts both on the metal speciation in solution and on the chemical behaviour of the surface of the sorbing material, and thus indirectly on the sorption mechanism. The effect of the initial pH of the solution on the cadmium sorption by raw state chitin has been studied in static conditions. The approach used is the determination of the sorption kinetics and equilibria for different values of initial pH (pH < 7-7.5). An increase of the initial pH value of the solution leads to an increase of the cadmium sorption capacity by chitin at the equilibrium. The Langmuir model has revealed to be convenient for a mathematical description of the sorption isotherms obtained. (J.S.)

  2. Effect of pH and temperature on the binding of bilirubin to human erythrocyte membranes

    Indian Academy of Sciences (India)

    H Rashid; Mohammad K Ali; S Tayyab

    2000-06-01

    Effect of pH and temperature on the binding of bilirubin to human erythrocyte membranes was studied by incubating the membranes at different pH and temperatures and determining the bound bilirubin. At all pH values, the amount of membrane-bound bilirubin increased with the increase in bilirubin-to-albumin molar ratios (B/As), being highest at lower pH values in all cases. Further, linear increase in bound bilirubin with the increase in bilirubin concentration in the incubate was observed at a constant B/A and at all pH values. However, the slope value increased with the decrease in pH suggesting more bilirubin binding to membranes at lower pH values. Increase in bilirubin binding at lower pH can be explained on the basis of increased free bilirubin concentration as well as more conversion of bilirubin dianion to monoanion. Temperature dependence of bilirubin binding to membranes was observed within the temperature range of 7°–60°C, showing minimum binding at 27°C and 37°C which increased on either side. Increase in bilirubin binding at temperatures lower than 20°C and higher than 40°C can be ascribed to the change in membrane topography as well as bilirubin-albumin interaction.

  3. The voltage dependence of GABAA receptor gating depends on extracellular pH.

    Science.gov (United States)

    Pytel, Maria; Mercik, Katarzyna; Mozrzymas, Jerzy W

    2005-11-28

    Recent studies have indicated that changes in extracellular pH and in membrane voltage affect the gamma-amino-n-butyric acid type A receptor gating mainly by altering desensitization and binding. To test whether the effects of membrane potential and pH are additive, their combined actions were investigated. By analyzing the current responses to rapid gamma-amino-n-butyric acid applications, we found that the current to voltage relationship was close to linear at acid pH but the increasing pH induced an inward rectification. Desensitization was enhanced at depolarizing potentials, but this strongly depended on pH, being weak at acidic and strong at basic pH values. A similar trend was observed for the onset rate of responses to saturating gamma-amino-n-butyric acid concentration. These data provide evidence that the voltage sensitivity of GABAA receptors depends on extracellular pH.

  4. The voltage dependence of GABAA receptor gating depends on extracellular pH

    Science.gov (United States)

    Pytel, Maria; Mercik, Katarzyna; Mozrzymas, Jerzy W.

    2007-01-01

    Recent studies have indicated that changes in extracellular pH and in membrane voltage affect the γ-amino-n-butyric acid type A receptor gating mainly by altering desensitization and binding. To test whether the effects of membrane potential and pH are additive, their combined actions were investigated. By analyzing the current responses to rapid γ-amino-n-butyric acid applications, we found that the current to voltage relationship was close to linear at acid pH but the increasing pH induced an inward rectification. Desensitization was enhanced at depolarizing potentials, but this strongly depended on pH, being weak at acidic and strong at basic pH values. A similar trend was observed for the onset rate of responses to saturating γ-amino-n-butyric acid concentration. These data provide evidence that the voltage sensitivity of GABAA receptors depends on extracellular pH. PMID:16272885

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

    Science.gov (United States)

    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 (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.

  6. A measure of endosomal pH by flow cytometry in Dictyostelium

    Directory of Open Access Journals (Sweden)

    Cosson Pierre

    2009-01-01

    Full Text Available Abstract Background Dictyostelium amoebae are frequently used to study the organization and function of the endocytic pathway, and specific protocols are essential to measure the dynamics of endocytic compartments and their internal pH. Findings We have revisited these classical protocols to measure more accurately endosomal pH, making use of a fluorescent probe (Oregon green more adequate for very acidic pH values. This pH-sensitive probe was combined with a pH-insensitive marker, in order to visualize simultaneously endosome dynamics and pH changes. Finally, a flow cytometer was used to measure endosomal pH in individual cells. Conclusion Using these simple protocols the endosomal pH of endocytic compartments can be assessed accurately, revealing the extreme acidity of Dictyostelium lysosomes (pH

  7. Establishment of a gaseous pH control concept in microbioreactors

    DEFF Research Database (Denmark)

    Zainal Alam, Muhd Nazrul Hisham Bin; Schäpper, Daniel; Gernaey, Krist

    2012-01-01

    Existing methods for pH control in bench-scale bioreactor systems often cannot be directly adapted for microbioreactors. This is because microbioreactors are commonly designed to work with constant volumes, operate bubble-free and have no headspace, which technically rules out any possibility...... of adding acid/base solution for pH control in microbioreactors. This work reports on the establishment of a gaseous pH control concept in microbioreactors where pH control was achieved by dosing of ammonia (NH3, 20 000 ppm) and pure carbon dioxide (CO2) gases to respectively; increase and lower the pH...... gases coupled to a simple on/off controller results in a satisfactorily control performance (pH control accuracy = + 0.1 of the set point value and system responses of a few minutes were achieved) within the dynamic measuring range of the optical sensor spot which is between pH 6 and 8....

  8. Traceability of pH to the Mole

    OpenAIRE

    Maria Filomena Camões; Bárbara Anes

    2015-01-01

    Free acidity of aqueous solutions was initially defined in 1909 by Søren Peter Lauritz Sørensen as pH = −lgcH+ (c/mol·dm−3 or m/mol·kg−1 of the free hydrogen ions in solution, H+) soon (1910) was changed to pH = paH+ = −lgaH+, integrating the new concepts of activity, ai and activity coefficient γi, for the ionic species i under concern, H+ in this case; it is ai = −lg(miγi). Since individual ions do not exist alone in solution, primary pH values cannot be assigned solely by experimental me...

  9. The Value of Value Sets

    DEFF Research Database (Denmark)

    Sløk-Madsen, Stefan Kirkegaard; Christensen, Jesper

    The world over classrooms in business schools are being taught that corporate values can impact performance. The argument is typically that culture matter more than strategy plans and culture can be influenced and indeed changed by a shared corporate value set. While the claim seems intuitively a...... a unique contribution to the effects of investment in shared company values, and to whether agent rationality can be fundamentally changed by committed organizational efforts.......The world over classrooms in business schools are being taught that corporate values can impact performance. The argument is typically that culture matter more than strategy plans and culture can be influenced and indeed changed by a shared corporate value set. While the claim seems intuitively...... and anecdotally true surprisingly little hard evidence has been produced either for or against. This study attempts to rectify this. The study claims that for corporate values to matter they must at least align, and potentially alter, employee decision-making hence their concept of optimality and rational...

  10. Effect of pH on the Hydrothermal Synthesis of BN Nanocrystals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Boron nitride (BN) has been synthesized using hydrothermal synthesis method. The experimental results showed that the pH value of the reaction solution has an important effect on the yield and phases of BN samples. As the pH value decreased, the content of cBN increased and the yield improved. The increase in cBN content is resulted from the conversion of oBN into cBN under hydrothermal condition, and the growth of cBN nanocrystals may due to the decrease in the reaction speed, thus the crystalline perfection of BN improved when the pH value decreased.

  11. pH Tolerance in Freshwater Bacterioplankton: Trait Variation of the Community as Measured by Leucine Incorporation

    OpenAIRE

    Bååth, Erland; Kritzberg, Emma

    2015-01-01

    pH is an important factor determining bacterial community composition in soil and water. We have directly determined the community tolerance (trait variation) to pH in communities from 22 lakes and streams ranging in pH from 4 to 9 using a growth-based method not relying on distinguishing between individual populations. The pH in the water samples was altered to up to 16 pH values, covering in situ pH ± 2.5 U, and the tolerance was assessed by measuring bacterial growth (Leu incorporation) in...

  12. [Spatiotemporal variation of soil pH in Guangdong Province of China in past 30 years].

    Science.gov (United States)

    Guo, Zhi-Xing; Wang, Jing; Chai, Min; Chen, Ze-Peng; Zhan, Zhen-Shou; Zheng, Wu-Ping; Wei, Xiu-Guo

    2011-02-01

    Based on the 1980s' soil inventory data and the 2002-2007 soil pH data of Guangdong Province, the spatiotemporal variation of soil pH in the Province in past 30 years was studied. In the study period, the spatial distribution pattern of soil pH in the Province had less change (mainly acidic), except that in Pearl River Delta and parts of Qingyuan and Shaoguan (weak alkaline). The overall variation of soil pH was represented as acidification, with the average pH value changed from 5.70 to 5.44. Among the soil types in the Province, alluvial soil had an increased pH, lateritic red soil, paddy soil, and red soil had a large decrement of pH value, and lime soil was most obvious in the decrease of pH value and its area percentage. The soil acidification was mainly induced by soil characteristics, some natural factors such as acid rain, and human factors such as unreasonable fertilization and urbanization. In addition, industrialization and mining increased the soil pH in some areas.

  13. TO STUDY PH DISORDERS IN SEVERE ACUTE MALNUTRITION

    Directory of Open Access Journals (Sweden)

    Saurabh Kumar

    2014-10-01

    Full Text Available OBJECTIVE: To study pH disorders in severe acute malnutrition. DESIGN: A prospective, cohort, observational study. SETTING: Severe malnutrition treatment unit in a tertiary level care hospital in central India. PARTICIPANTS: 202 children between 6 to 60 months of age. METHODOLOGY: Radial artery sample was taken at admission which was analyzed by automated blood gas analyzer; results were studied and correlated with nutritional status at discharge/outcome. STATISTICAL ANALYSIS: The data were analyzed using SPSS 20. Univariate and bivariate analysis of data was done using the Student t test and two-tailed Fisher exact or chi-square test. RESULTS: Out of 202 children studied 51.5% were males and 48.5% were females, 16.8% children had pH 7.45. The mean values of pH, HCO3- , PCO2, PO2 and Cl- were 7.42, 17.1mmol/l, 25.22 mmHg, 93.71mmHg and 109.05mmol/l respectively. Most children (n = 173/202; 85.6% were discharged, 11(5.4 % expired and 18 patients left the treatment. In pH 7.46 group. CONCLUSION: In this study, metabolic acidosis with hyperchloremia was associated with poor outcome. There is no significant change in the duration of hospital stay and rate of weight gain in any pH group.

  14. Crystallization and evaluation of hen egg-white lysozyme crystals for protein pH titration in the crystalline state.

    Science.gov (United States)

    Iwai, Wakari; Yagi, Daichi; Ishikawa, Takuya; Ohnishi, Yuki; Tanaka, Ichiro; Niimura, Nobuo

    2008-05-01

    To observe the ionized status of the amino acid residues in proteins at different pH (protein pH titration in the crystalline state) by neutron diffraction, hen egg-white lysozyme was crystallized over a wide pH range (2.5-8.0). Crystallization phase diagrams at pH 2.5, 6.0 and 7.5 were determined. At pH diagram, and at pH > 4.5 the border shifted to the right (higher precipitant concentration). The qualities of these crystals were characterized using the Wilson plot method. The qualities of all crystals at different pH were more or less equivalent (B-factor values within 25-40). It is expected that neutron diffraction analysis of these crystals of different pH provides equivalent data in quality for discussions of protein pH titration in the crystalline state of hen egg-white lysozyme.

  15. Effect of pH and VFA on hydrolysis of organic solid waste

    NARCIS (Netherlands)

    Veeken, A.H.M.; Kalyuzhnyi, S.; Scharff, H.; Hamelers, H.V.M.

    2000-01-01

    The anaerobic hydrolysis rate of organic solid waste was studied at fixed volatile fatty acid (VFA) concentrations ranging from 3 to 30 g COD/L and fixed pH values between 5 and 7. For separate control of both VFA and pH, a special completely mixed reactor was designed. In this way, it was possible

  16. Emotional Value of Applied Textiles

    DEFF Research Database (Denmark)

    Bang, Anne Louise

    2011-01-01

    The present PhD thesis is conducted as an Industrial PhD project in collaboration with the Danish company Gabriel A/S (Gabriel), which designs and produces furniture textiles and ‘related products’ for manufacturers of furniture. A ‘related textile product’ is e.g. processing of piece goods......, upholstery, mounting etc. This PhD project addresses the challenges of the textile industry, where the global knowledge economy increasingly forces companies to include user-participation and value innovation in their product development. My project revolves around the challenges which the textile designers...... and multifaceted field of design research with a particular focus on textile design including the discourse and methodology used in the field of design. In addition the project relates to the Participatory Design approach and to the design research fields which focus on emotional aspects of design. Based on my...

  17. Combined effect of pH and heating conditions on the physical properties of Alaska pollock surimi gels.

    Science.gov (United States)

    Lee, Myeong Gi; Yoon, Won Byong; Park, Jae W

    2017-06-01

    Physical properties of Alaska pollock surimi paste were investigated as affected by pH (4.0 and 6.0-10.0) and heating conditions (slow and fast). The highest values of gel strength and deformability, as shown by breaking force and penetration distance, were obtained at pH 7.5-8.0, while the lowest values were at pH 10.0 followed by pH 6.0 and pH 6.5, respectively. Two-step slow heating process increased the breaking strength value nearly two times higher than one-step fast heating. The effect of pH was strikingly high at pH 7.5 when gels were prepared using 2-step heating, indicating the pH dependence of endogenous transglutaminase. However, the highest gel strength was obtained at pH 8.0 when gels were prepared in fast heating. Whiteness value (L - 3b*) increased significantly (p heated gels showed the lowest yellowness, resulting in whiter appearance, probably due to the effect of reduced browning reaction. The uniqueness of this study was to measure the combined effect of pH and heating conditions on the gel texture and color. There were various studies dealing with pH or heating conditions independently. As the primary character for surimi seafood is gel texture and color. The highest values of gel strength and deformability, as shown by breaking force and penetration distance, were obtained at pH 7.5-8.0, while the lowest values were at pH 10.0 followed by pH 6.0 and pH 6.5, respectively. Two-step slow heating process increased the breaking strength value nearly two times higher than one-step fast heating. Whiteness value (L - 3b*) increased significantly as pH increased from 6.0 to 6.5, but thereafter decreased significantly as pH increased. L* value (lightness) and b* value (yellowness) continuously decreased as the pH is shifted from 6.0 to 10. Fast heated gels showed the lowest yellowness, resulting in whiter appearance. © 2016 Wiley Periodicals, Inc.

  18. Effects of pH and Carbon Source on Synechococcus PCC 7002 Cultivation: Biomass and Carbohydrate Production with Different Strategies for pH Control.

    Science.gov (United States)

    De Farias Silva, Carlos Eduardo; Sforza, Eleonora; Bertucco, Alberto

    2017-02-01

    Synechococcus PCC 7002 is an interesting species in view of industrial production of carbohydrates. The cultivation performances of this species are strongly affected by the pH of the medium, which also influences the carbohydrate accumulation. In this work, different methods of pH control were analyzed, in order to obtain a higher production of both Synechococcus biomass and carbohydrates. To better understand the influence of pH on growth and carbohydrate productivity, manual and automatic pH regulation in CO2 and bicarbonate system were applied. The pH value of 8.5 resulted the best to achieve both of these goals. From an industrial point of view, an alternative way to maintain the pH practically constant during the entire period of cultivation is the exploitation of the bicarbonate-CO2 buffer system, with the double aim to maintain the pH in the viability range and also to provide the amount of carbon required by growth. In this condition, a high concentration of biomass (6 g L(-1)) and carbohydrate content (around 60 %) were obtained, which are promising in view of a potential use for bioethanol production. The chemical equilibrium of C-N-P species was also evaluated by applying the ionic balance equations, and a relation between the sodium bicarbonate added in the medium and the equilibrium value of pH was discussed.

  19. Functional genomics of pH homeostasis in Corynebacterium glutamicum revealed novel links between pH response, oxidative stress, iron homeostasis and methionine synthesis

    Directory of Open Access Journals (Sweden)

    Persicke Marcus

    2009-12-01

    Full Text Available Abstract Background The maintenance of internal pH in bacterial cells is challenged by natural stress conditions, during host infection or in biotechnological production processes. Comprehensive transcriptomic and proteomic analyses has been conducted in several bacterial model systems, yet questions remain as to the mechanisms of pH homeostasis. Results Here we present the comprehensive analysis of pH homeostasis in C. glutamicum, a bacterium of industrial importance. At pH values between 6 and 9 effective maintenance of the internal pH at 7.5 ± 0.5 pH units was found. By DNA microarray analyses differential mRNA patterns were identified. The expression profiles were validated and extended by 1D-LC-ESI-MS/MS based quantification of soluble and membrane proteins. Regulators involved were identified and thereby participation of numerous signaling modules in pH response was found. The functional analysis revealed for the first time the occurrence of oxidative stress in C. glutamicum cells at neutral and low pH conditions accompanied by activation of the iron starvation response. Intracellular metabolite pool analysis unraveled inhibition of the TCA and other pathways at low pH. Methionine and cysteine synthesis were found to be activated via the McbR regulator, cysteine accumulation was observed and addition of cysteine was shown to be toxic under acidic conditions. Conclusions Novel limitations for C. glutamicum at non-optimal pH values were identified by a comprehensive analysis on the level of the transcriptome, proteome, and metabolome indicating a functional link between pH acclimatization, oxidative stress, iron homeostasis, and metabolic alterations. The results offer new insights into bacterial stress physiology and new starting points for bacterial strain design or pathogen defense.

  20. pH值和阴离子对吡啶2,6-二羧酸在金纳米颗粒表面的增强拉曼散射的影响%Influence of pH Value and Anion on Surface Enhanced Raman Scattering of 2,6-Pyridinedicarboxylic Acid on Gold Nanoparticle Suface

    Institute of Scientific and Technical Information of China (English)

    罗伟琪; 成汉文; 宦双燕; 温国丽; 陈媛媛; 沈国励; 俞汝勤

    2011-01-01

    Surface enhanced Raman scattering (SERS) was used for the detection of 2 , 6-pyridinedicar boxylic acid (DPA) , a biomarker for bacterial spores. The gold nanoparticles of 60 nm diameters were immobilized on a polished Au electrode using PVP as an adhesive layer. We demonstrated that the fabricated SERS substrates were steady and highly sensitive. The influence of pH and anions about the adsorption mechanism of DPA on colloidal gold nanoparticles has been examined by SERS. The results showed that using a gold nanoparticle/polyvinylpyrrolidone/gold substrate (AuNPs/PVP/Au)for detection of DPA exhibited a maximum enhancement of SERS signal at low pH, however the SERS features and intensity of DPA were found to weaken when pH was greater than pKa2. The effect of different anions on the adsorption mechanism of this molecule was also investigated, the SERS effect on Au NPs-Au substrate had changed, since the anions may replace the partial sites of the citrate on the gold surface. Owing to the different adsorption mechanism of the three anions, the difference of SERS intensity was observed on the addition of different anions.%表面增强拉曼散射(SERS)被用于检测细菌芽抱中的一种重要的标志物吡啶2,6-羧酸(DPA).以聚乙烯吡啶烷酮(PVP)为粘合剂,将60 nm的金粒子组装到表面打磨光滑的金电极上,制备稳定、灵敏的SERS基底.通过不同pH值下吸附在金基底上的DPA的SERS特征,考察DPA分子吸附构型发生的变化,并分析酸根离子对其吸附的影响.结果表明:在强酸条件下,DPA在Au NPs/PVP/Au基底上的SERS信号能达到最大增强;当pH值大于DPA二级解离常数时,DPA的SERS特征逐渐减弱.在DPA中引入不同酸根盐时,后者会取代纳米金表面的柠檬酸根所占的部分位点,改变Au NPs-Au基底的SERS增强性能.3种酸根吸附性能不同,所以获得的光谱强度存在差异.

  1. Short communication: Teat skin pH.

    Science.gov (United States)

    Fox, L K; Oura, L Y; Ames, C R

    2003-12-01

    Changes in teat skin surface pH were studied over 12 wk in 99 lactating Holstein cows. Half the udder of each cow routinely received postmilking disinfection, and the other half served as control. Measures of pH were made on all teats at weekly intervals. Teat skin pH was affected by treatment but not week. Mean teat skin pH measures were: 7.18 (+/- 0.64) and 7.53 (+/- 0.46) for treatment and control teats. In study II, pH teat skin measures were made hourly on 16 cows, starting 2 h before milking, immediately before a milking, immediately after a milking, and for 2 h postmilking. Teat skin pH was significantly lower for treatment teats and was lower for all teats postmilking.

  2. Influence of pH on Nanofluids' Viscosity and Thermal Conductivity

    Institute of Scientific and Technical Information of China (English)

    WANG Xian-Ju; LI Xin-Fang

    2009-01-01

    Aiming at the dispersion stability of nanoparticles regarded as the guide of heat transfer enhancement, we investigate the viscosity and the thermal conductivity of Cu and Al2O3 nanoparticles in water under different pH values. The results show that there exists an optimal pH value for the lowest viscosity and the highest thermal conductivity, and that at the optimal pH value the nanofluids containing a small amount of nanoparticles have noticeably higher thermal conductivity than that of the base fluid without nanoparticles. For the two nanofluids the enhancements of thermal conductivity are observed up to 13% (Al2Oa-water) or 15% (Cu-water) at 0.4 wt%,respectively. Therefore, adjusting the pH values is suggested to improve the stability and the thermal conductivity for practical applications of nanofluid.

  3. Effects of pH on aquatic biodegradation processes

    Directory of Open Access Journals (Sweden)

    R. F. Krachler

    2009-01-01

    Full Text Available To date, little is known about the pH-stimulated mineralization of organic matter in aquatic environments. In this study, we investigated biodegradation processes in alkaline waters. Study site is a large shallow soda lake in Central Europe (Neusiedler See/Ferto. The decomposition rate of plant litter was measured as a function of pH by incubating air-saturated lake-water samples in contact with Phragmites litter (leaves from the littoral vegetation. All samples showed high decomposition rates (up to 32% mass loss within 35 days and a characteristic two-step degradation mechanism. During the degradation process, the solid plant litter was dissolved forming humic colloids. Subsequently, the humic colloids were mineralized to CO2 in the water column. The decomposition rate was linearly related to pH. Increasing pH values accelerated significantly the leaching of humic colloids as well as the final degradation process. The observed two-step mechanism controls the wetland/lake/air carbon fluxes, since large quantities of humic colloids are currently produced in the reed belt, exported through wind-driven circulations and incorporated into the open lake foodweb. At present, the lake is rapidly shrinking due to peat deposition in the littoral zone, whereas it has been resistant to silting-up processes for thousands of years. In order to investigate the cause of this abrupt change, the chemical composition of the lake-water was measured during 1995–2007. A thorough analysis of these data revealed that major lake-water discharges through the lake's artificial outlet channel led to a decline in salinity and alkalinity. According to our estimates, the lake's original salinity and alkalinity was 70–90% higher compared to the present conditions, with the consequence of substantially lower pH values in the present lake. The observed pH dependence of reed litter biodegradation rates points to a causal connection between low pH

  4. Uranium-induced oxidative stress in Arabidopsis thaliana: influence of pH on uranium toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Horemans, N.; Saenen, E.; Vanhoudt, N.; Vandenhove, H.; Biermans, G.; Van Hees, M. [SCK.CEN (Belgium); Vangronsveld, J.; Cuypers, A. [Hasselt University (Belgium)

    2014-07-01

    Chemical toxicity of uranium (U) is dependent on U speciation. An important factor controlling the speciation is the environmental pH level. While U uptake and translocation at different pH levels has been reported by several authors (Ebbs et al. 1998, Laurette et al. 2012), little information is available on the cellular responses after U exposure under contrasted chemical speciation conditions. Therefore, the main objective of this study includes the influence of the medium pH on U toxicity and the mechanisms that are involved herein. Hydroponically grown Arabidopsis thaliana plants were exposed to different U concentrations during 3 days at pH 4.5 or pH 7.5. Exposing Arabidopsis thaliana roots to U resulted in a significant decrease in fresh weight at both pH levels. The effective concentration that caused 50% growth reduction (EC50) at pH 4.5 (28 ± 1.5 μM U) was approximately 2.5 times lower than the EC50 value observed at pH 7.5 (70 ± 10 μM U). This may indicate that U is more toxic at low pH. In addition, the difference can be explained by the fact that for similar nominal U concentrations, U was more readily taken up by the roots at low pH, possibly leading to more adverse effects. The anti-oxidative defence mechanisms that were activated after U exposure were similar at both pH levels, although the activation occurred at lower U concentrations at pH 4.5 as compared to pH 7.5. For example, microRNA398b/c was activated under U stress. This microRNA post-transcriptionally regulates the expression of copper/zinc superoxide dismutases, enzymes important in scavenging reactive oxygen species (ROS). As such, a significant increase in the MIR398b/c transcript levels was observed at pH 4.5 after exposure to 50 μM U, while at pH 7.5 a significant induction was only observed after exposure to 100 μM U. Although the U concentration in the leaves was low, the U translocation at pH 4.5 was approximately 3 times lower than the translocation found at pH 7.5. However

  5. Central Binomial Sums, Multiple Clausen Values and Zeta Values

    CERN Document Server

    Borwein, J M; Kamnitzer, J

    2000-01-01

    We find and prove relationships between Riemann zeta values and central binomial sums. We also investigate alternating binomial sums (also called Ap\\'ery sums). The study of non-alternating sums leads to an investigation of different types of sums which we call multiple Clausen values. The study of alternating sums leads to a tower of experimental results involving polylogarithms in the golden ratio. In the non-alternating case, there is a strong connection to polylogarithms of the sixth root of unity, encountered in the 3-loop Feynman diagrams of {\\tt hep-th/9803091} and subsequently in hep-ph/9910223, hep-ph/9910224, cond-mat/9911452 and hep-th/0004010.

  6. Fair Value or Market Value?

    OpenAIRE

    Bogdan Cosmin Gomoi; Lavinia Denisia Cuc; Robert Almaşi

    2014-01-01

    When taking into consideration the issue of defining the “fair value” concept, those less experimented in the area often fall in the “price trap”, which is considered as an equivalent of the fair value of financial structures. This valuation basis appears as a consequence of the trial to provide an “accurate image” by the financial statements and, also, as an opportunity for the premises offered by the activity continuing principle. The specialized literature generates ample controversies reg...

  7. Evaluation of pH of bathing soaps and shampoos for skin and hair care

    Directory of Open Access Journals (Sweden)

    Jose Tarun

    2014-01-01

    Full Text Available Background: Normal healthy skin has potential of hydrogen (pH range of 5.4-5.9 and a normal bacterial flora. Use of soap with high pH causes an increase in skin pH, which in turn causes an increase in dehydrative effect, irritability and alteration in bacterial flora. The majority of soaps and shampoos available in the market do not disclose their pH. Aims and Objectives: The aim of this study was to assess the pH of different brands of bathing soaps and shampoos available in the market. Materials and Methods: The samples of soaps and shampoos were collected from shops in the locality. The samples of different brands are coded before the analysis of the pH. Solution of each sample was made and pH was measured using pH meter. Results: Majority of the soaps have a pH within the range of 9-10. Majority of the shampoos have a pH within the range of 6-7. Conclusions: The soaps and shampoos commonly used by the population at large have a pH outside the range of normal skin and hair pH values. Therefore, it is hoped that before recommending soap to patient especially those who have sensitive and acne prone skin, due consideration is given to the pH factor and also that manufacturers will give a thought to pH of soaps and shampoos manufactured by them, so that their products will be more skin and hair friendly.

  8. Determination of Sulfuric Acid in Anodizing and Hardcoating Solutions by Acid-Base Titration Using a pH Meter

    Science.gov (United States)

    1989-10-01

    6.99 5 6.95 6 6.95 X(avg) 6.99 Sn 0.04 *The pH values are standardized against primary standard buffer solutions in the potentiometry chapter of...Sn 0.02 *The pH values are standardized against primary standard buffer solutions in the potentiometry chapter of Reference 3 using a pH meter. 9

  9. Effect of pH on saturated hydraulic conductivity and soil dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Suarez, D.L.; Roades, J.D.; Lavado, R.; Grieve, C.M.

    The adverse effects of exchangeable sodium on soil hydraulic conductivity (K) are well known, but at present only sodicity and total electrolyte concentration are used in evaluating irrigation water suitability. In arid areas, high sodicity is often associatd with high dissolved carbonate and thus high pH, but in humid areas high sodicity may be associated with low pH. To evaluate the effect of pH (as an independent variable) on K, solutions with the same SAR and electrolyte level were prepared at pH 6, 7, 8, and 9. Saturated K values were determined at constant flux in columns packed at a bulk density of 1.5 Mg m/sup -3/. At pH 9, saturated K values were lower than at pH 6 for a montmorillonitic and kaolinitic soil. For a vermiculitic soil with lower organic carbon and higher silt content, pH changes did not cause large K differences. Decreases in K were not reversible on application of waters with higher electrolyte levels. The results from the K experiments were generally consistent with optical transmission measurements of dispersion. Although anion adsorption was at or below detection limits and cation exchange capacity (CEC) was only slightly dependent on pH, differences in pH effects on K among soils are likely due to differences in quantities of variable-charge minerals and organic matter.

  10. The Final Frontier of pH and the Undiscovered Country Beyond

    Science.gov (United States)

    Bal, Wojciech; Kurowska, Ewa; Maret, Wolfgang

    2012-01-01

    The comparison of volumes of cells and subcellular structures with the pH values reported for them leads to a conflict with the definition of the pH scale. The pH scale is based on the ionic product of water, Kw = [H+]×[OH−].We used Kw [in a reversed way] to calculate the number of undissociated H2O molecules required by this equilibrium constant to yield at least one of its daughter ions, H+ or OH− at a given pH. In this way we obtained a formula that relates pH to the minimal volume VpH required to provide a physical meaning to Kw, (where NA is Avogadro’s number). For example, at pH 7 (neutral at 25°C) VpH = 16.6 aL. Any deviation from neutral pH results in a larger VpH value. Our results indicate that many subcellular structures, including coated vesicles and lysosomes, are too small to contain free H+ ions at equilibrium, thus the definition of pH based on Kw is no longer valid. Larger subcellular structures, such as mitochondria, apparently contain only a few free H+ ions. These results indicate that pH fails to describe intracellular conditions, and that water appears to be dissociated too weakly to provide free H+ ions as a general source for biochemical reactions. Consequences of this finding are discussed. PMID:23049874

  11. Empirical Essays on the Labor Market Outcomes of PhD Graduates

    DEFF Research Database (Denmark)

    Pedersen, Heidi Skovgaard

    that PhDs accelerate growth. A major objective has been to direct more PhDs to the industry to use their skills to monetize knowledge. However, we have limited evidence on how PhDs are absorbed into the labor market, how the market values PhD labor, and how PhDs value the possibility to work...... in the private sector. The dissertation investigates determinants of labor market decisions among recent cohorts of PhDs in Denmark to assess how the increasing number of PhDs is absorbed into the economy. Based on econometric models, it examines what factors trigger individual career decisions and supply...... opportunities. The researcher career path has surely evolved as society’s visions for PhDs’ utility in the search for knowledge, and this has led to more diverse career paths. The dissertation sheds light on how career choices are formed in the current labor market structure that new PhDs encounter early...

  12. Influence of pH on fermentative hydrogen production from sweet sorghum extract

    Energy Technology Data Exchange (ETDEWEB)

    Antonopoulou, Georgia; Gavala, Hariklia N.; Skiadas, Ioannis V.; Lyberatos, Gerasimos [Department of Chemical Engineering, University of Patras, 1 Karatheodori st., GR 26500 Patras (Greece); Institute of Chemical Engineering and High Temperature Chemical Processes, GR 26504 Patras (Greece)

    2010-03-15

    The present study focused on the influence of pH on the fermentative hydrogen production from the sugars of sweet sorghum extract, in a continuous stirred tank bioreactor. The reactor was operated at a Hydraulic Retention Time of 12 h and a pH range of 3.5-6.5. The maximum hydrogen production rate and yield were obtained at pH 5.3 and were 1752 {+-} 54 mL H{sub 2}/d or 3.50 {+-} 0.07 L H{sub 2}/L reactor/d and 0.93 {+-} 0.03 mol H{sub 2}/mol glucose consumed or 10.51 L H{sub 2}/kg sweet sorghum, respectively. The main metabolic product at this pH value was butyric acid. The hydrogen productivity and yield were still at high levels for the pH range of 5.3-4.7, suggesting a pH value of 4.7 as optimum for hydrogen production from an economical point of view, since the energy demand for chemicals is lower at this pH. At this pH range, the dominant fermentation product was butyric acid but when the pH culture sharply decreased to 3.5, hydrogen evolution ceased and the dominant metabolic products were lactic acid and ethanol. (author)

  13. Influence of pH on the thixotropy of magnesium aluminum hydroxide-kaolinite suspension

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The influence of pH on the thixotropy of pure kaolinite suspension and magnesium alu minum hydroxide (Mg-Al-MMH)-kaolinite suspension was studied. The results show that the thixotropic type of pure kaolinite suspension was not affected by pH studied in the range of 3.60 12.00. The thixotropic type of Mg-Al-MMH-kaolinite suspension with mass ratio (R) value of MMH to kaolinite 0.029 transformed from complex thixotropy into positive thixotropy with increasing of pH in the range of pH 3.83- 12.00, and the type of thixotropy of Mg-AI-MMH-kaolinite suspension with R= 0.129 transformed from positive thixotropy into complex thixotropy with increasing of pH in the range of pH 3.70- 11.96.

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

    Science.gov (United States)

    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 ABE) with offline pH measurements with a standard glass electrode as reference.

  15. Valuing hope.

    Science.gov (United States)

    McMillan, John; Walker, Simon; Hope, Tony

    2014-01-01

    This article argues that hope is of value in clinical ethics and that it can be important for clinicians to be sensitive to both the risks of false hope and the importance of retaining hope. However, this sensitivity requires an understanding of the complexity of hope and how it bears on different aspects of a well-functioning doctor-patient relationship. We discuss hopefulness and distinguish it, from three different kinds of hope, or 'hopes for', and then relate these distinctions back to differing accounts of autonomy. This analysis matters because it shows how an overly narrow view of the ethical obligations of a clinician to their patient, and autonomy, might lead to scenarios where patients regret the choices they make.

  16. Modeling of salt and pH gradient elution in ion-exchange chromatography.

    Science.gov (United States)

    Schmidt, Michael; Hafner, Mathias; Frech, Christian

    2014-01-01

    The separation of proteins by internally and externally generated pH gradients in chromatofocusing on ion-exchange columns is a well-established analytical method with a large number of applications. In this work, a stoichiometric displacement model was used to describe the retention behavior of lysozyme on SP Sepharose FF and a monoclonal antibody on Fractogel SO3 (S) in linear salt and pH gradient elution. The pH dependence of the binding charge B in the linear gradient elution model is introduced using a protein net charge model, while the pH dependence of the equilibrium constant is based on a thermodynamic approach. The model parameter and pH dependences are calculated from linear salt gradient elutions at different pH values as well as from linear pH gradient elutions at different fixed salt concentrations. The application of the model for the well-characterized protein lysozyme resulted in almost identical model parameters based on either linear salt or pH gradient elution data. For the antibody, only the approach based on linear pH gradients is feasible because of the limited pH range useful for salt gradient elution. The application of the model for the separation of an acid variant of the antibody from the major monomeric form is discussed.

  17. Fair Value or Market Value?

    Directory of Open Access Journals (Sweden)

    Bogdan Cosmin Gomoi

    2014-12-01

    Full Text Available When taking into consideration the issue of defining the “fair value” concept, those less experimented in the area often fall in the “price trap”, which is considered as an equivalent of the fair value of financial structures. This valuation basis appears as a consequence of the trial to provide an “accurate image” by the financial statements and, also, as an opportunity for the premises offered by the activity continuing principle. The specialized literature generates ample controversies regarding the “fair value” concept and the “market value” concept. The paper aims to debate this issue, taking into account various opinions.

  18. Effect of initial ph on growth characteristics and fermentation properties of Saccharomyces cerevisiae.

    Science.gov (United States)

    Liu, Xingyan; Jia, Bo; Sun, Xiangyu; Ai, Jingya; Wang, Lihua; Wang, Cheng; Zhao, Fang; Zhan, Jicheng; Huang, Weidong

    2015-04-01

    As the core microorganism of wine making, Saccharomyces cerevisiae encounter low pH stress at the beginning of fermentation. Effect of initial pH (4.50, 3.00, 2.75, 2.50) on growth and fermentation performance of 3 S. cerevisiae strains Freddo, BH8, Nº.7303, different tolerance at low pH, chosen from 12 strains, was studied. The values of yeast growth (OD600 , colony forming units, cell dry weight), fermentation efficiency (accumulated mass loss, change of total sugar concentration), and fermentation products (ethanol, glycerol, acetic acid, and l-succinic acid) at different pH stress were measured. The results showed that the initial pH of must was a vital factor influencing yeast growth and alcoholic fermentation. Among the 3 strains, strain Freddo and BH8 were more tolerant than Nº.7303, so they were affected slighter than the latter. Among the 4 pH values, all the 3 strains showed adaptation even at pH 2.50; pH 2.75 and 2.50 had more vital effect on yeast growth and fermentation products in contrast with pH 4.50 and 3.00. In general, low initial pH showed the properties of prolonging yeast lag phase, affecting accumulated mass loss, changing the consumption rate of total sugar, increasing final content of acetic acid and glycerol, and decreasing final content of ethanol and l- succinic acid, except some special cases. Based on this study, the effect of low pH on wine products would be better understood and the tolerance mechanism of low pH of S. cerevisiae could be better explored in future.

  19. Oxidation in fish oil enriched mayonnaise : Ascorbic acid and low pH increase oxidative deterioration

    DEFF Research Database (Denmark)

    Jacobsen, Charlotte; Timm Heinrich, Maike; Meyer, Anne S.

    2001-01-01

    oxidation. It is proposed that iron bridges between the egg yolk proteins low-density lipoproteins, lipovitellin, and phosvitin at the oil-water interface are broken at low pH values, whereby iron ions become accessible as oxidation initiators. In the presence of ascorbic acid, oxidation is further enhanced......The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil- water interface into the aqueous phase at all pH levels......, but this effect of ascorbic acid was strongest at low pH (pH 3.8- 4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted...

  20. Hubungan antara pH Susu dengan Jumlah Sel Somatik Sebagai Parameter Mastitis Subklinik

    Directory of Open Access Journals (Sweden)

    M. Sudarwanto

    2008-08-01

    Full Text Available The aim of this research was to measure the relationship of the pH value to the somatic cell count as a parameter of sub clinical mastitis detection. Two hundreds quarter milk samples were used in this research and the test (the pH value, IPB-1 mastitis test and Breed method was done in parallel way. The results showed that 152 samples from 200 samples (76% tested with Breed method came from the herds which suffered from sub-clinical mastitis and with IPB-1 test showed that 145 (72.5% of the samples had positive reaction. Using pH meter, it showed that 44 samples (22 % had pH > 6.75, presumed suffered from sub-clinical mastitis and 2 samples (1% showed pH < 6.30 (6.25 and 6.28. At the same time, these two samples showed a negative reaction with IPB-1 test and had somatic cell count of 360,000/ml and 280,000/ml, each. It also showed that there was a close relationship between pH value and IPB-1 test. The conclusion of this research was that the measurement of pH value was not a sensitive method for detecting sub-clinical mastitis.

  1. Oxidation in fish oil enriched mayonnaise: ascorbic acid and low pH increase oxidative deterioration.

    Science.gov (United States)

    Jacobsen, C; Timm, M; Meyer, A S

    2001-08-01

    The effect of ascorbic acid (0-4000 ppm) and pH (3.8-6.2) on oxidation and levels of iron and copper in various fractions of mayonnaise enriched with 16% fish oil was investigated. Ascorbic acid induced release of iron from the assumed oil-water interface into the aqueous phase at all pH levels, but this effect of ascorbic acid was strongest at low pH (pH 3.8-4.2). Ascorbic acid generally promoted formation of volatile oxidation compounds and reduced the peroxide value in mayonnaises. Peroxide values and total volatiles generally increased with decreasing pH values, suggesting that low pH promoted oxidation. It is proposed that iron bridges between the egg yolk proteins low-density lipoproteins, lipovitellin, and phosvitin at the oil-water interface are broken at low pH values, whereby iron ions become accessible as oxidation initiators. In the presence of ascorbic acid, oxidation is further enhanced due to the reduction of Fe(3+) to Fe(2+) that rapidly catalyzes lipid oxidation via lipid hydroperoxide decomposition at the oil-water interface in mayonnaise.

  2. In situ variation of cervical mucus pH during exposure to atmospheric air

    Directory of Open Access Journals (Sweden)

    Correa C.H.M.

    2001-01-01

    Full Text Available The objective of the present study was to determine if exposure of cervical mucus to air during specular examination could modify mucus pH. Detection of changes is justified because of their possible interference with sperm-mucus interaction, since an acidic pH is unfavorable to sperm penetration and is associated with infertility due to the cervical factor. Twenty women with good quality mucus were evaluated. pH measurements of ecto- and endocervical mucus were made in situ using a glass electrode after 0-, 5- and 10-min exposure to air. There was a progressive alkalinization of mucus pH. Mean values of ectocervical mucus pH were 6.91, 7.16 and 7.27, while mean values of endocervical mucus pH were 7.09, 7.34 and 7.46 at 0, 5 and 10 min, respectively. Significant differences were found between the mean values obtained at 0 and 5 min, and at 0 and 10 min (P<0.05, whereas the differences in mean values at 5 and 10 min were not significant at either site. We conclude that 5 to 10 min of exposure to atmospheric air affects cervical mucus pH in a significant way. Since tests used to evaluate sperm-mucus interaction generally have not considered this possibility, we suggest that they should be performed immediately after mucus collection in order to avoid misinterpretation of the results.

  3. Commercial soft drinks: pH and in vitro dissolution of enamel.

    Science.gov (United States)

    Jain, Poonam; Nihill, Patricia; Sobkowski, Jason; Agustin, Ma Zenia

    2007-01-01

    Most soft drinks are acidic in nature and exposure to these drinks may result in enamel erosion. This study sought to measure the pH of 20 commercial brands of soft drinks, the dissolution of enamel resulting from immersion in these drinks, and the influence of pH on enamel loss. Comparison of the erosive potential of cola versus non-cola drinks as well as regular sugared and diet versions of the same brands was undertaken. The pH was measured immediately after opening the soft drink can. Enamel slices obtained from freshly extracted teeth were immersed in the soft drinks and weighed at baseline and after 6, 24, and 48 hours of immersion. Non-cola drinks had significantly higher pH values than cola drinks but showed higher mean percent weight loss. By contrast, sugared versions of the cola and non-cola drinks showed significantly lower pH values and higher mean percent weight loss than their diet counterparts. The pH value of the soft drink did not have a significant influence on the mean percent weight loss (r = -0.28). Prolonged exposure to soft drinks can lead to significant enamel loss. Non-cola drinks are more erosive than cola drinks. Sugared versions of cola and non-cola drinks proved to be more erosive than their diet counterparts. The erosive potential of the soft drinks was not related to their pH value.

  4. Urbanism PhD Research 2008 - 2010

    NARCIS (Netherlands)

    Van der Hoeven, F.D.; Brand, N.; Van der Burg, L.; Çalışkan, O.; Tan, E.R.; Wang, C.-Y.; Zhou, J.

    2009-01-01

    To ensure the quality of the Ph.D. research the Department introduced a special procedure for periodic evaluation: after a period of nine months the potential Ph.D. candidates are asked to present their research design, theoretical framework and methodological approach to the members of the Departme

  5. On Calibration of pH Meters

    Directory of Open Access Journals (Sweden)

    Da-Ming Zhu

    2005-04-01

    Full Text Available The calibration of pH meters including the pH glass electrode, ISE electrodes,buffers, and the general background for calibration are reviewed. Understanding of basicconcepts of pH, pOH, and electrode mechanism is emphasized. New concepts of pH, pOH,as well as critical examination of activity, and activity coefficients are given. Theemergence of new solid state pH electrodes and replacement of the salt bridge with aconducting wire have opened up a new horizon for pH measurements. A pH buffer solutionwith a conducting wire may be used as a stable reference electrode. The misleadingunlimited linear Nernstian slope should be discarded. Calibration curves with 3 nonlinearportions for the entire 0—14 pH range due to the isoelectric point change effect areexplained. The potential measurement with stirring or unstirring and effects by double layer(DL and triple layer (TL will be discussed.

  6. Coaching af ph.d.-studerende

    DEFF Research Database (Denmark)

    Godskesen, Mirjam Irene

    Rapporten danner grundlag for at etablere et koncept for ph.d.-coaching. Erfaringerne fra et 2-årigt projekt om ph.d.-coaching i SCKK regi beskrives. De centrale temaer er tilrettelæggelse af den individuelle coaching, typiske temaer i coachingen og arbejdsdeling mellem coach og vejleder. Der er...

  7. Salivary pH: A diagnostic biomarker

    Directory of Open Access Journals (Sweden)

    Sharmila Baliga

    2013-01-01

    Full Text Available Objectives: Saliva contains a variety of host defense factors. It influences calculus formation and periodontal disease. Different studies have been done to find exact correlation of salivary biomarkers with periodontal disease. With a multitude of biomarkers and complexities in their determination, the salivary pH may be tried to be used as a quick chairside test. The aim of this study was to analyze the pH of saliva and determine its relevance to the severity of periodontal disease. Study Design: The study population consisted of 300 patients. They were divided into three groups of 100 patients each: Group A had clinically healthy gingiva, Group B who had generalized chronic gingivitis and Group C who had generalized chronic periodontitis. The randomized unstimulated saliva from each patient was collected and pH was tested. Data was analyzed statistically using analysis of variance technique. Results: The salivary pH was more alkaline for patients with generalized chronic gingivitis as compared with the control group (P = 0.001 whereas patients with generalized chronic periodontitis had more acidic pH as compared with the control group (P = 0.001. Conclusion: These results indicate a significant change in the pH depending on the severity of the periodontal condition. The salivary pH shows significant changes and thus relevance to the severity of periodontal disease. Salivary pH may thus be used as a quick chairside diagnostic biomarker.

  8. Ph og børnenes rum

    DEFF Research Database (Denmark)

    de Coninck-Smith, Ning

    2008-01-01

    Arkiteten og kulturkritikeren PH tegnede to bygninger til børn, nemlig fabriksbørnehaven ved Dehns Vaskeri fra 1948 og det ombyggede børnehjem Mindet fra 1954. Bidraget diskuterer PH's særlige greb om arkitektur til børn og placerer det ind i samtidens diskussion om børn, deres udvikling og behov....

  9. Evaluation of boron isotope ratio as a pH proxy in the deep sea coral Desmophyllum dianthus: Evidence of physiological pH adjustment

    Science.gov (United States)

    Anagnostou, E.; Huang, K.-F.; You, C.-F.; Sikes, E. L.; Sherrell, R. M.

    2012-10-01

    The boron isotope ratio (δ11B) of foraminifers and tropical corals has been proposed to record seawater pH. To test the veracity and practicality of this potential paleo-pH proxy in deep sea corals, samples of skeletal material from twelve archived modern Desmophyllum dianthus (D. dianthus) corals from a depth range of 274-1470 m in the Atlantic, Pacific, and Southern Oceans, ambient pH range 7.57-8.05, were analyzed for δ11B. The δ11B values for these corals, spanning a range from 23.56 to 27.88, are found to be related to seawater borate δ11B by the linear regression: δ11Bcoral=(0.76±0.28) δ11Bborate+(14.67±4.19) (1 standard error (SE)). The D. dianthus δ11B values are greater than those measured in tropical corals, and suggest substantial physiological modification of pH in the calcifying space by a value that is an inverse function of seawater pH. This mechanism partially compensates for the range of ocean pH and aragonite saturation at which this species grows, enhancing aragonite precipitation and suggesting an adaptation mechanism to low pH environments in intermediate and deep waters. Consistent with the findings of Trotter et al. (2011) for tropical surface corals, the data suggest an inverse correlation between the magnitude of a biologically driven pH offset recorded in the coral skeleton, and the seawater pH, described by the equation: ΔpH=pH recorded by coral-seawater pH=-(0.75±0.12) pHw+(6.88±0.93) (1 SE). Error analysis based on 95% confidence interval(CI) and the standard deviation of the regression residuals suggests that the uncertainty of seawater pH reconstructed from δ11Bcoral is ±0.07 to 0.12 pH units. This study demonstrates the applicability of δ11B in D. dianthus to record ambient seawater pH and holds promise for reconstructing oceanic pH distribution and history using fossil corals.

  10. Valuing vaccination

    Science.gov (United States)

    Bärnighausen, Till; Bloom, David E.; Cafiero-Fonseca, Elizabeth T.; O’Brien, Jennifer Carroll

    2014-01-01

    Vaccination has led to remarkable health gains over the last century. However, large coverage gaps remain, which will require significant financial resources and political will to address. In recent years, a compelling line of inquiry has established the economic benefits of health, at both the individual and aggregate levels. Most existing economic evaluations of particular health interventions fail to account for this new research, leading to potentially sizable undervaluation of those interventions. In line with this new research, we set forth a framework for conceptualizing the full benefits of vaccination, including avoided medical care costs, outcome-related productivity gains, behavior-related productivity gains, community health externalities, community economic externalities, and the value of risk reduction and pure health gains. We also review literature highlighting the magnitude of these sources of benefit for different vaccinations. Finally, we outline the steps that need to be taken to implement a broad-approach economic evaluation and discuss the implications of this work for research, policy, and resource allocation for vaccine development and delivery. PMID:25136129

  11. WATER HARDNESS AS AN IMPORTANT PARAMETER OF PH

    Directory of Open Access Journals (Sweden)

    Žigmund Tóth

    2013-02-01

    Full Text Available Quality of final product is to great extent influenced by intermediate products that are formed during beer production. In addition quality of pH is one of the most important properties that forms suitable medium for activity of enzymes complexes that have crucial influence on character of produced wort. Moreover enzymes influence the yield of production process and quality of final product as well. Quality of boiling water and especially its hardness have crucial task in terms of keeping optimal qualitative parameters. Water hardness is given by amount of salts, mainly calcium and magnesium salts. It is expressed as absolute hardness which is given by sum of temporary (carbonate and permanent (noncarbonate hardness. In our work we solved the effect of total water hardness on final pH of various intermediate products. We used different water samples and we prepared variants of total hardness by stirring of unpurified water with distilled water thus we achieved various values of hardness. For comparison we prepared several brews with regard to combinations of unpurified water and distilled water. Higher pH of boiling water was caused due to higher water alkalinity that negatively affected enzyme complex present in used malt. Presence of hydrogenphosphates in used malt had high buffering ability and pH lowering ability. Such unfavorable result could be adjust by use of various additions of acidulates that would have in great extent influence on beer final price therefore boiling water adjustment seems to be the most acceptable approach.

  12. Preparation and influence of pH on the dynamic magnetic property of magnetic FeCoC films

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Hongmei; Wei, Jinwu; Zhu, Zengtai; Cao, Derang; Liu, Qingfang [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Wang, Jianbo, E-mail: wangjb@lzu.edu.cn [Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou 730000 (China); Key Laboratory for Special Function Materials and Structural Design of the Ministry of the Education, Lanzhou University, Lanzhou 730000 (China)

    2016-07-01

    FeCoC films were successfully prepared by electrochemical deposition method in different citric acid concentrations and pH values. The morphology, structure and magnetic properties were investigated. FeCoC films deposited at different citric acid concentrations have good soft magnetic performance. As the pH value increases from 2.49 to 6.02, the atomic ratio of Fe:Co range from 0.72 to 0.95. The coercivities of the films deposited at different pH values first increase and then decrease with increasing pH. The resonance frequency of the films can be tuned by controlling the pH value, and in an appropriate pH value a wide absorption peak can be obtained. - Highlights: • We have successfully prepared FeCoC soft magnetic films by electrochemical deposition method. • The resonance frequency can be controlled by changing pH value. • A widely absorption peak will be obtained when the pH value is appropriate.

  13. Effect of pH on surface energy of glass and Teflon and theoretical prediction of Staphylococcus aureus adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Hamadi, F. [Equipe de recherche: Microbiologie et biochimie appliquee a l' agroalimentaire, l' environnement et la sante. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco); Latrache, H., E-mail: latracheh@yahoo.fr [Equipe de recherche: Microbiologie et biochimie appliquee a l' agroalimentaire, l' environnement et la sante. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco); Zekraoui, M. [Equipe de recherche: Genie industriel, agroalimentaire et environnement. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco); Ellouali, M. [Equipe de recherche: Microbiologie et biochimie appliquee a l' agroalimentaire, l' environnement et la sante. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco); Bengourram, J. [Equipe de recherche: Genie industriel, agroalimentaire et environnement. Faculte de Sciences et Techniques, B. P 523, Beni, Mellal (Morocco)

    2009-05-05

    The surface energy of glass and Teflon at various pH values was examined. Contact angle was used to determine physico-chemical substratum properties. The surface energy of both substratums including, hydrophobicity, and electron donor/electron acceptor (Lewis acid-base properties) were found to depend on pH of contact solution. The maximum of hydrophobicity (higher negative value of {Delta}G{sub iwi}) was obtained at pH 11 and pH 6.5 for glass and Teflon respectively. The electron donor property was higher at pH 5 and pH 3 for glass and Teflon respectively. Moreover, prediction of Staphylococcus aureus adhesion on both substratums was estimated by calculating the total interaction free energy ({Delta}G{sup Tot}). Based on the value of {Delta}G{sup Tot}, S. aureus should adhere to glass at pH 2, pH 3 and pH 11 with the maximal adhesion obtained at pH 3 and pH 11. For Teflon, regardless of pH values, S. aureus should be able to attach on this substratum with the high adhesion level at pH 5. The relation between surface energy of substratum and the total interaction free energy was also examined. Based on this relation and the value of the components of total interaction free energy, we show that adhesion to glass could be governed by both short range forces (Lewis acid-bases forces) and by long range forces (van der Waals forces) and the adhesion to Teflon could be mediated only by the short range forces.

  14. Analysis of Student Understanding of Science Concepts Including Mathematical Representations: Ph Values and the Relative Differences of pH Values

    Science.gov (United States)

    Park, Eun-Jung; Choi, Kyunghee

    2013-01-01

    In general, mathematical representations such as formulae, numbers, and graphs are the inseparable components in science used to better describe or explain scientific phenomena or knowledge. Regardless of their necessity and benefit, science seems to be difficult for some students, as a result of the mathematical representations and problem…

  15. Exploring the physiologic role of human gastroesophageal reflux by analyzing time-series data from 24-h gastric and esophageal pH recordings.

    Science.gov (United States)

    Lu, Luo; Mu, John C; Sloan, Sheldon; Miner, Philip B; Gardner, Jerry D

    2014-07-16

    Our previous finding of a fractal pattern for gastric pH and esophageal pH plus the statistical association of sequential pH values for up to 2 h led to our hypothesis that the fractal pattern encodes information regarding gastric acidity and that depending on the value of gastric acidity, the esophagus can signal the stomach to alter gastric acidity by influencing gastric secretion of acid or bicarbonate. Under our hypothesis values of gastric pH should provide information regarding values of esophageal pH and vice versa. We used vector autoregression, a theory-free set of inter-related linear regressions used to measure relationships that can change over time, to analyze data from 24-h recordings of gastric pH and esophageal pH. We found that in pH records from normal subjects, as well as from subjects with gastroesophageal reflux disease alone and after treatment with a proton pump inhibitor, gastric pH values provided important information regarding subsequent values of esophageal pH and values of esophageal pH provided important information regarding subsequent values of gastric pH. The ability of gastric pH and esophageal pH to provide information regarding subsequent values of each other was reduced in subjects with gastroesophageal reflux disease compared to normal subjects. Our findings are consistent with the hypothesis that depending on the value of gastric acidity, the esophagus can signal the stomach to alter gastric acidity, and that this ability is impaired in subjects with gastroesophageal reflux disease.

  16. Influence of early pH decline on calpain activity in porcine muscle

    DEFF Research Database (Denmark)

    Pomponio, Luigi; Ertbjerg, Per; Karlsson, Anders H

    2010-01-01

    . The rate of pH decline early post-mortem differed between the three groups, but the ultimate pH values were similar at 24 h. Calpain activity and autolysis from 1 to 72 h post-mortem were determined using casein zymography and studied in relation to myofibrillar fragmentation. Colour and drip loss were......This study investigated the influence of post-mortem pH decline on calpain activity and myofibrillar degradation.From 80 pigs, 30 Longissimus dorsi (LD) muscles were selected on the basis of pH values at 3 h post-mortem and classified into groups of 10 as fast, intermediate and slow pH decline...... measured. A faster decrease in pH resulted in reduced level of l-calpain activity and increased autolysis of the enzyme, and hence an earlier loss of activity due to activation of l-calpain in muscles with a fast pH decline. Paralleling the l-calpain activation in muscles with a fast pH decline a higher...

  17. Coagulation behavior of polyaluminum chloride:Effects of pH and coagulant dosage☆

    Institute of Scientific and Technical Information of China (English)

    Ning Wei; Zhongguo Zhang; Dan Liu; Yue Wu; Jun Wang; Qunhui Wang

    2015-01-01

    Coagulation mechanisms of polyaluminum chloride (PACl) at various dosages were studied using a conventional jar test at different final and initial pH values during treating kaolin suspension. The optimal final pH and dosages for PACl were obtained based on residual turbidity and zeta potential of flocs. The coagulation zones at various PACl dosages and solution pH values were developed and compared with those of alum. It is found that the optimal mechanism under acidic condition is charge neutralization, while alkaline condition wil facilitate the coagulation of PACl. Both charge neutralization coagulation and sweep coagulation can achieve high coagulation efficiency under the alkaline condition ranging from final pH 7.0 to 10.0. Stabilization, charge neutralization destabilization, restabilization and sweep zones occur successively with increasing PACl dosages with the final pH values fixed at 7.0 and 8.0, but restabilization zone disappears at final pH 10.0. When the final pH is not controlled and consequently decreases with increasing PACl dosage, no typical sweep zone can be observed and the coagulant efficiency decreases at high PACl dosage. It seems that the final pH is more meaningful than the initial pH for coagulation. Charge neutralization coagulation efficiency is dominated by zeta potential of flocs and PACl precipitates. The charge neutralization and sweep coagulation zones of PACl are broader in the ranges of coagulant dosage and pH than those of alum. The results are helpful for us to treat water and wastewa-ter using PACl and to understand the coagulation process of PACl.

  18. pH influence on antibacterial efficacy of common antiseptic substances.

    Science.gov (United States)

    Wiegand, Cornelia; Abel, Martin; Ruth, Peter; Elsner, Peter; Hipler, Uta-Christina

    2015-01-01

    Wound infection plays an important role in compromised wound healing. A high bioburden impairs healing and leads to formation of a chronic wound. Distinctly higher pH values were observed in chronic wounds compared to acute wounds. However, there is only limited knowledge of pH dependency on the antibacterial efficacy of common antimicrobial substances. This study investigated the pH influence on the antimicrobial efficacy of povidone (PVP)-iodine, silver nitrate, chlorhexidine, octenidine and polihexanide against Staphylococcus aureus and Pseudomonas aeruginosa using the agar diffusion test and microplate laser nephelometry. The bactericidal activity of chlorhexidine and octenidine was mainly pH-independent in a pH range of 5.0-9.0. In contrast, polihexanide showed a significant efficacy increase at a higher pH. It was also found that the influence of the pH on antiseptics differs among species of bacteria. For instance, S. aureus exhibited an increasing sensitivity against silver nitrate with rising pH whereas the effect on P. aeruginosa was found to be distinctly decreased. The antimicrobial effect of PVP-iodine was strongly diminished with rising pH. The shift towards higher pH values in chronic wounds compared to acute wounds makes it imperative to know whether the antimicrobial efficacy of applied antimicrobial substances is altered by different pH levels. The results suggest that application of polihexanide might be advantageous for the management of wound infections, as both S. aureus and P. aeruginosa exhibited an increased susceptibility with rising pH. © 2015 S. Karger AG, Basel.

  19. Exhaled breath condensate pH assays.

    Science.gov (United States)

    Davis, Michael D; Hunt, John

    2012-08-01

    Airway pH is central to the physiologic function and cellular biology of the airway. The causes of airway acidification include (1) hypopharyngeal gastric acid reflux with or without aspiration through the vocal cords, (2) inhalation of acid fog or gas (such as chlorine), and (3) intrinsic airway acidification caused by altered airway pH homeostasis in infectious and inflammatory disease processes. The recognition that relevant airway pH deviations occur in lung diseases is opening doors to new simple and inexpensive therapies. This recognition has resulted partly from the ability to use exhaled breath condensate as a window on airway acid-base balance.

  20. ATLAS PhD Grant Scheme

    CERN Multimedia

    2016-01-01

    In this #CERNandSociety video, the 3 PhD students, awarded the ATLAS PhD Grant in 2015, talk about their research work within the ATLAS Collaboration and how this experience has shaped their future. Find out more about the ATLAS PhD Grant Scheme: cern.ch/ATLASPhDGrant This programme is just one of the many #CERNandSociety projects at CERN. Find out more and how you can be involved: http://cern.ch/go/pBt7

  1. Influence of pH on wound-healing: a new perspective for wound-therapy?

    Science.gov (United States)

    Schneider, Lars Alexander; Korber, Andreas; Grabbe, Stephan; Dissemond, Joachim

    2007-02-01

    Wound healing is a complex regeneration process, which is characterised by intercalating degradation and re-assembly of connective tissue and epidermal layer. The pH value within the wound-milieu influences indirectly and directly all biochemical reactions taking place in this process of healing. Interestingly it is so far a neglected parameter for the overall outcome. For more than three decades the common assumption amongst physicians was that a low pH value, such as it is found on normal skin, is favourable for wound healing. However, investigations have shown that in fact some healing processes such as the take-rate of skin-grafts require an alkaline milieu. The matter is thus much more complicated than it was assumed. This review article summarises the existing literature dealing with the topic of pH value within the wound-milieu, its influence on wound healing and critically discusses the currently existing data in this field. The conclusion to be drawn at present is that the wound pH indeed proves to be a potent influential factor for the healing process and that different pH ranges are required for certain distinct phases of wound healing. Further systematic data needs to be collected for a better understanding of the pH requirements under specific circumstances. This is important as it will help to develop new pH targeted therapeutic strategies.

  2. Factors affecting the pH and electrical conductivity of MgO–ethylene glycol nanofluids

    Indian Academy of Sciences (India)

    Saheed A Adio; Mohsen Sharifpur; Josua P Meyer

    2015-09-01

    The pH and electrical conductivity are important properties of nanofluids that have not been widely studied, especially with regard to temperature and ultrasonication energy. To study the factors that affect the pH and electrical conductivity of magnesium oxide–ethylene glycol (MgO–EG) nanofluid, the effects of temperature, volume fraction, particle size and ultrasonication energy were investigated. Two different sizes of MgO were dispersed in EG base fluid up to the volume fraction of 3%, and the pH and electrical conductivity were monitored between the temperatures of 20 and 70°C. Characterization by transmission electron microscopy and size analyses revealed the morphology and sizes of the nanoparticle samples. The pH values dropped consistently with the increase of temperature, while electrical conductivity value increased with the increase of temperature. The experimental result showed that the increase in the MgO volume fraction increased both the pH and electrical conductivity values of the MgO–EG nanofluid. There was no recognizable influence of ultrasonication energy density on the pH and electrical conductivity of the nanofluid; therefore, it was concluded that temperature, volume fraction and particle size are the predominant factors affecting both the pH and electrical conductivity of MgO–EG nanofluid within the present experimental conditions.

  3. Effects of pH and acetic acid on homoacetic fermentation of lactate by Clostridium formicoaceticum.

    Science.gov (United States)

    Tang, I C; Okos, M R; Yang, S T

    1989-10-20

    Clostridium formicoaceticum homofermentatively converts lactate to acetate at 37 degrees C and pH 6.6-9.6. However, this fermentation is strongly inhibited by acetic acid at acidic pH. The specific growth rate of this organism decreased from a maximum at pH 7.6 to zero at pH 6.6. This inhibition effect was found to be attributed to both H(+) and undissociated acetic acid. At pH values below 7.6, the H(+) inhibited the fermentation following non-competitive inhibition kinetics. The acetic acid inhibition was found to be stronger at a lower medium pH. At pH 6.45-6.8, cell growth was found to be primarily limited by a maximum undissociated acetic acid concentration of 0.358 g/L (6mM). This indicates that the undissociated acid, not the dissociated acid, is the major acid inhibitor. At pH 7.6 or higher, this organism could tolerate acetate concentrations of higher than 0.8M, but salt (Na(+)) became a strong inhibitor at concentrations of higher than 0.4M. Acetic acid inhibition also can be represented by noncompetitive inhibition kinetics. A mathematical model for this homoacetic fermentation was also developed. This model can be used to simulate batch fermentation at any pH between 6.9 and 7.6.

  4. Effects of pH on the crystallographic structure and magnetic properties of electrodeposited cobalt nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, N. [Department of Physics, University of Engineering and Technology, Lahore 54890 (Pakistan); Shamaila, S., E-mail: drshamaila.uet@gmail.com [Department of Physics, University of Engineering and Technology, Lahore 54890 (Pakistan); Sharif, R.; Wali, H. [Department of Physics, University of Engineering and Technology, Lahore 54890 (Pakistan); Naseem, S.; Riaz, S. [Centre for Solid state Physics, University of the Punjab, Lahore (Pakistan); Khaleeq-ur-Rahman, M. [Department of Physics, University of Engineering and Technology, Lahore 54890 (Pakistan)

    2015-03-01

    Anodic aluminum oxide templates with pore diameter of 40 nm and inter pore separation of 100 nm are prepared by two step anodization in 0.3 M oxalic acid solution. These templates are used to fabricate dc-deposited Co nanowires at different pH values of acidic bath. Continuous and densely packed nanowires having length ∼8 µm are observed. The hcp configuration appeared at moderate and high pH whereas both fcc and hcp phases are observed at low pH. However the crystallinity distorted at high pH due to formation of polycrystalline structure of cobalt nanowires. Alignment of easy-axis of nanowires can be tailored by varying pH of solution. - Highlights: • Variation in the structure of dc deposited cobalt nanowires can be obtained by varying pH of acidic bath. • The hcp structure is stable at room temperature with low voltage deposition for electrodeposited Co nanowires. Co with fcc structure, is stable at temperatures above 422 °C or at pH<3 with high potential. • The hcp (100) plane is obtained with pH∼3.5 and (101) is stable at pH∼5.5 due to variation in temperature inside the pores with respect to the pH. • Alignment of easy-axis of nanowires can be tailored by varying pH of solution.

  5. Effect of operational pH on biohydrogen production from food waste using anaerobic batch reactors.

    Science.gov (United States)

    Lee, Chaeyoung; Lee, Sewook; Han, Sun-Kee; Hwang, Sunjin

    2014-01-01

    This study was performed to investigate the influence of operational pH on dark H(2) fermentation of food waste by employing anaerobic batch reactors. The highest maximum H(2) yield was 1.63 mol H(2)/mol hexoseadded at operational pH 5.3, whereas the lowest maximum H(2) yield was 0.88 mol H(2)/mol hexoseadded at operational pH 7.0. With decreasing operational pH values, the n-butyrate concentration tended to increase and the acetate concentration tended to decrease. The highest hydrogen conversion efficiency of 11.3% was obtained at operational pH 5.3, which was higher than that (8.3%) reported by a previous study (Kim et al. (2011) 'Effect of initial pH independent of operational pH on hydrogen fermentation of food waste', Bioresource Technology 102 (18), 8646-8652). The new result indicates that the dark fermentation of food waste was stable and efficient in this study. Fluorescence in situ hybridization (FISH) analysis showed that Clostridium species Cluster I accounted for 84.7 and 13.3% of total bacteria at operational pH 5.3 and pH 7.0, respectively, after 48 h operation.

  6. Experimental and theoretical evaluation of nanodiamonds as pH triggered drug carriers

    KAUST Repository

    Yan, Jingjing

    2012-01-01

    Nanodiamond (ND) and its derivatives have been widely used for drug, protein and gene delivery. Herein, experimental and theoretical methods have been combined to investigate the effect of pH on the delivery of doxorubicin (DOX) from fluorescein labeled NDs (Fc-NDs). In the endosomal recycling process, the nanoparticle will pass from mildly acidic vesicle to pH ≈ 4.8; thus, it is important to investigate DOX release from NDs at different pH values. Fc-NDs released DOX dramatically under acidic conditions, while an increase in the DOX loading efficiency (up to 6.4 wt%) was observed under basic conditions. Further theoretical calculations suggest that H + weakens the electrostatistic interaction between ND surface carboxyl groups and DOX amino groups, and the interaction energies at pH < 7, pH 7 and pH > 7 are 10.4 kcal mol -1, 25.0 kcal mol -1 and 27.0 kcal mol -1 respectively. Cellular imaging experiments show that Fc-NDs are readily ingested by breast adenocarcinoma (BA) cells and cell viability tests prove that they can be utilized as a safe drug delivery vehicle. Furthermore, pH triggered DOX release has been tested in vitro (pH 7.4 and pH 4.83) in breast adenocarcinoma (BA) cells. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.

  7. Leachability and desorption of PCBs from soil and their dependency on pH and dissolved organic matter

    Energy Technology Data Exchange (ETDEWEB)

    Badea, Silviu-Laurentiu, E-mail: badeasilviu@gmail.com; Mustafa, Majid; Lundstedt, Staffan; Tysklind, Mats

    2014-11-15

    pH affects both soil–water partitioning coefficient (K{sub d}) of polychlorinated biphenyls (PCBs) and dissolved organic matter (DOM), thereby influencing PCBs' leachability from contaminated soils. To explore these incompletely understood interactions, the leachability of 11 selected PCBs in a naturally aged soil was investigated in pH static leaching tests spanning a wide pH range (2 to 9). The K{sub d} was calculated for each of the PCBs, based on their observed concentrations in the soil and leachates obtained from each test. The concentration and composition of DOM in each leachate were also determined, the latter using FTIR spectroscopy. Correlations between the DOM's FTIR spectra and K{sub d} values were investigated by orthogonal projections to latent structures. The log K{sub d}-values varied among the PCB congeners and were most variable at low pH, but the values for all studied congeners decreased with increasing pH, by up to 3 log units (for PCB 187). In the pH 5–7 interval, an abrupt decrease in log K{sub d} values with increases in pH was observed, although the total organic carbon content remained relatively stable. The FTIR data indicate that fulvic and humic acids in DOM partially deprotonate as the pH rises from 5 to 7. - Highlights: • The log K{sub d}-values of 11 selected PCBs were investigated in pH static leaching tests • The log K{sub d}-values of all PCBs decreased with increasing pH, by up to 3 log units • The de-protonation of humics may explain why K{sub d}-values fell as pH rose from 5 to 7.

  8. Preparation of acridine orange-doped silica nanoparticles for pH measurement

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jinshui, E-mail: jsliu@sina.com; Zang, Lingjie; Wang, Yiru; Liu, Guoning

    2014-03-15

    Acridine orange was first encapsulated into silica shell via a facile reverse microemusion method to built core–shell fluorescent nanoparticles. The nanoparticles are all in spherical shape and have a narrow size distribution, and its application as a optical pH sensor has been demonstrated. This novel sensor is based on the pH-dependent fluorescence intensities of acridine orange in different pH value. The fluorescence intensity of acridine orange-doped silica nanoparticles was decreased by increasing pH value. Under optimum conditions, the changes of fluorescence intensity were proportional to the pH value in the range of 8.00–10.90. In addition, the sensor can be easily separated by centrifugation and adds no pollution to the environment compared to the free dyes. Furthermore, the effects of ionic strength and co-existing substances were proved to have little influence on the determination of pH. The sensor has been successfully applied to determine the pH of two artificial samples. Hence, the core–shell fluorescent nanoparticles show potential for practical application. -- Highlights: • Acridine orange was encapsulated into silica shell via a facile reverse microemusion method to built core–shell fluorescent nanoparticles. • The fluorescence intensity of acridine orange-doped silica nanoparticles was decreased by increasing pH value. • Its can be used as an optical pH sensor. • The sensor can be easily separated by centrifugation and adds no pollution to the environment compared to the free dyes. • The sensor has been successfully applied to determine the pH of artificial samples.

  9. Effects of the pH value of an acid environment on early growth and physiology of Medicago sativa W525%环境酸度对紫花苜蓿早期生长和生理的影响

    Institute of Scientific and Technical Information of China (English)

    李剑峰; 师尚礼; 张淑卿

    2010-01-01

    采用沙培的方式研究酸性土壤中土壤酸度对紫花苜蓿生理和生长的影响.结果表明,pH值在5~6的弱酸性环境为苜蓿的最适生长环境,这一酸度范围内幼苗生长正常或受到促进,如单株叶片数高于对照(pH=7)处理23.6%~27.2%、单叶面积高出对照20.87%~25.50%,叶绿素含量高出对照31.2%~27.9%,差异均达显著水平(P<0.05).而出苗率、株高、根瘤数、根瘤等级、根长和地上、地下生物量亦高于对照;而pH值低于4的环境酸度为低适生长环境,可使苜蓿幼苗受到严重胁迫,出苗率、株高、单叶面积、单株叶片数、根瘤数、根长和地上、地下生物量均低于其他处理.在不同土壤酸度下,质膜透性、叶绿素含量、光化学效率(Fv/Fo)等均存着显著差异(P<0.05),pH<4的各项生理指标均明显低于pH≥5的处理,其中地上生物量和根系活力分别不足对照处理的55.6%和61.1% (P<0.05).

  10. Life at acidic pH imposes an increased energetic cost for a eukaryotic acidophile.

    Science.gov (United States)

    Messerli, Mark A; Amaral-Zettler, Linda A; Zettler, Erik; Jung, Sung-Kwon; Smith, Peter J S; Sogin, Mitchell L

    2005-07-01

    Organisms growing in acidic environments, pHpH. We begin to investigate this premise by determining the magnitude of the transmembrane electrochemical H+ gradient in an acidophilic Chlamydomonas sp. (ATCC PRA-125) isolated from the Rio Tinto, a heavy metal laden, acidic river (pH 1.7-2.5). This acidophile grows most rapidly at pH 2 but is capable of growth over a wide pH range (1.5-7.0), while Chlamydomonas reinhardtii is restricted to growth at pH>or=3 with optimal growth between pH 5.5 and 8.5. With the fluorescent H+ indicator, 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF), we show that the acidophilic Chlamydomonas maintains an average cytosolic pH of 6.6 in culture medium at both pH 2 and pH 7 while Chlamydomonas reinhardtii maintains an average cytosolic pH of 7.1 in pH 7 culture medium. The transmembrane electric potential difference of Chlamydomonas sp., measured using intracellular electrodes at both pH 2 and 7, is close to 0 mV, a rare value for plants, animals and protists. The 40,000-fold difference in [H+] could be the result of either active or passive mechanisms. Evidence for active maintenance was detected by monitoring the rate of ATP consumption. At the peak, cells consume about 7% more ATP per second in medium at pH 2 than at pH 7. This increased rate of consumption is sufficient to account for removal of H+ entering the cytosol across a membrane with relatively high permeability to H+ (7x10(-8) cm s-1). Our results indicate that the small increase in the rate of ATP consumption can account for maintenance of the transmembrane H+ gradient without the imposition of cell surface H+ barriers.

  11. Coping with PH over the Long Term

    Science.gov (United States)

    ... a career, nurturing healthy relationships and managing personal finances, become more difficult when you have PH. Meeting ... widely, a common theme that emerges is the importance of accepting not just that your life changed ...

  12. Brenda K. Edwards, PhD

    Science.gov (United States)

    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.

  13. A Simple Technique for Determining the pH of Whole Cigarette Smoke

    Directory of Open Access Journals (Sweden)

    Dong J

    2014-12-01

    Full Text Available A new technique has been developed to determine the pH of whole cigarette smoke. In this technique, whole smoke from ten cigarettes was trapped in 300 mL water containing 1% (w/v sodium chloride and the pH was determined on the resulting aqueous suspension of cigarette smoke. Two impingers with an extra coarse porosity fritted disc were used to dispense the smoke in the aqueous trapping medium. Cigarettes were smoked on a 20-port Borgwaldt RM 20/CS smoking machine using modified FTC (Federal Trade Commission conditions. The puff volume was adjusted to take a 35 mL puff as measured through the cigarette and the collection traps. This new technique accounts for the contributions to smoke pH from both the vapor phase and the particulate phase of smoke. The repeatability of this new technique was determined on eighteen replicates of a commercially available non-menthol, filter cigarette. Each measurement was done on a different day to check for a possible drift in pH with time. The mean pH value for the chosen sample was found to be 4.97 with a standard deviation of 0.07 pH units. The smoke pH values for over 150 commercially available cigarette brands with a variety of “tar” levels were determined. The smoke pH values had a range from 4.6 to 5.5, with an average of 4.79 and a maximum standard deviation of 0.10 pH units. An experimental flue cured cigarette had a smoke pH of around 5.0, while an experimental Burley cigarette had a smoke pH of 5.4. No correlation between smoke pH and “tar” or total particulate matter (TPM and between pH and nicotine levels was found. The purpose of the present study was to develop a practical, relatively simple laboratory method to measure the pH of a water solution of whole smoke, and was not intended to reflect, or have direct relevance for any biochemical or biological phenomena such as inhalability of smoke, flavor perception, nicotine ab-sorption, etc.”

  14. Phänomenologie schulischer Langeweile

    OpenAIRE

    Götz, Thomas; Frenzel, Anne C.

    2006-01-01

    Ziel der vorliegenden Studie war eine Identifizierung und Kategorisierung phänomenologischer Aspekte schulischer Langeweile. Hierzu wurden Daten von 50 Gymnasiasten der 9. Jahrgangsstufe (50% weiblich) erhoben. Die auf der Basis von Schüleraussagen generierten Kategorien zur Phänomenologie schulischer Langeweile erwiesen sich als sehr inhaltsheterogen und deuteten auf verschiedene Formen des Langeweileerlebens hin. Es wurden vier Formen schulischer Langeweile identifiziert und bezüglich der D...

  15. Effect of pH on the heavy metal-clay mineral interaction

    Energy Technology Data Exchange (ETDEWEB)

    Altyn, O.; Oezbelge, H.O.; Dogu, T.; Oezbelge, T.A. [Middle East Technical Univ., Ankara (Turkey)

    1997-12-31

    Adsorption and ion exchange of Pb and Cd on the surface of kaolinite and montmorillonite were studied with a strong emphasis on the pH values of solutions containing heavy metal ions. The pH range studied was 2.5 - 9. For kaolinite at a clay/solution ratio of 1/10 (w/w), Pb removal changes from 20 to 30% for an initial Pb concentration of 1640 ppm, and Cd removal changes from 10 to 20% for an initial Cd concentration of 1809 ppm. Due to its high exchange capacity, montmorillonite can remove more heavy metal than kaolinite. Removal rates for montmorillonite can reach up to 90% for both Pb and Cd. In the pH range of 3-6, there is a plateau for the removal rates. At pH values higher than 6, removal seems to increase artificially due to the precipitation of heavy metals. Under similar conditions for both clays, the rate of removal of Pb is always higher than that of Cd. As the pH value decreases for montmorillonite, there is a strong tendency for decreased surface area and swelling, as indicated by BET surface area measurements, adsorbed layer thickness and pore size distribution data. In the range of pH values studied, X-ray diffraction analysis showed the appearance of a characteristic (001) peak for montmorillonite, indicating that the crystalline structure of the clay was intact during the experiments.

  16. Autotrophic ammonia oxidation at low pH through urea hydrolysis.

    Science.gov (United States)

    Burton, S A; Prosser, J I

    2001-07-01

    Ammonia oxidation in laboratory liquid batch cultures of autotrophic ammonia oxidizers rarely occurs at pH values less than 7, due to ionization of ammonia and the requirement for ammonium transport rather than diffusion of ammonia. Nevertheless, there is strong evidence for autotrophic nitrification in acid soils, which may be carried out by ammonia oxidizers capable of using urea as a source of ammonia. To determine the mechanism of urea-linked ammonia oxidation, a ureolytic autotrophic ammonia oxidizer, Nitrosospira sp. strain NPAV, was grown in liquid batch culture at a range of pH values with either ammonium or urea as the sole nitrogen source. Growth and nitrite production from ammonium did not occur at pH values below 7. Growth on urea occurred at pH values in the range 4 to 7.5 but ceased when urea hydrolysis was complete, even though ammonia, released during urea hydrolysis, remained in the medium. The results support a mechanism whereby urea enters the cells by diffusion and intracellular urea hydrolysis and ammonia oxidation occur independently of extracellular pH in the range 4 to 7.5. A proportion of the ammonia produced during this process diffuses from the cell and is not subsequently available for growth if the extracellular pH is less than 7. Ureolysis therefore provides a mechanism for nitrification in acid soils, but a proportion of the ammonium produced is likely to be released from the cell and may be used by other soil organisms.

  17. What PhD students really want

    CERN Document Server

    Mao, Minnie

    2010-01-01

    The road to becoming an astronomer is exciting, but often fraught with danger and conflicting messages. A PhD student is inundated with catch-phrases such as "publish or perish" and "it's not about the quantity, but the quality of work". How do we know which advice to follow? How can we publish copious amounts of quality work in only three years so as to maximize our success in the future? How do we even know what "good quality" really is? With only a short time to prepare ourselves for the big wide world of Astronomy, what is the best way for a PhD student to maximize their research and ultimately maximize their success as a real astronomer? The PhD students of today are the astronomers of tomorrow, but their journey depends on a positive work environment in which they can thrive and improve. Here I present the results of a survey of current PhD students on how they believe they can maximize their success in science. I find that PhD students in Australia expect to write more papers during their PhD than is e...

  18. The effect of pH on phosphorus availability and speciation in an aquaponics nutrient solution.

    Science.gov (United States)

    Cerozi, Brunno da Silva; Fitzsimmons, Kevin

    2016-11-01

    The interaction between the main ions in aquaponics nutrient solutions affects chemical composition and availability of nutrients, and nutrient uptake by plant roots. This study determined the effect of pH on phosphorus (P) speciation and availability in an aquaponics nutrient solution and used Visual MINTEQ to simulate P species and P activity. In both experimental and simulated results, P availability decreased with increase in pH of aquaponics nutrient solutions. According to simulations, P binds to several cations leaving less free phosphate ions available in solution. High pH values resulted in the formation of insoluble calcium phosphate species. The study also demonstrated the importance of organic matter and alkalinity in keeping free phosphate ions in solution at high pH ranges. It is recommended though that pH in aquaponics systems is maintained at a 5.5-7.2 range for optimal availability and uptake by plants.

  19. Negative pH and extremely acidic mine waters from Iron Mountain, California

    Science.gov (United States)

    Nordstrom, D.K.; Alpers, C.N.; Ptacek, C.J.; Blowes, D.W.

    2000-01-01

    Extremely acidic mine waters with pH values as low as -3.6, total dissolved metal concentrations as high as 200 g/L, and sulfate concentrations as high as 760 g/L, have been encountered underground in the Richmond Mine at Iron Mountain, CA. These are the most acidic waters known. The pH measurements were obtained by using the Pitzer method to define pH for calibration of glass membrane electrodes. The calibration of pH below 0.5 with glass membrane electrodes becomes strongly nonlinear but is reproducible to a pH as low as -4. Numerous efflorescent minerals were found forming from these acid waters. These extreme acid waters were formed primarily by pyrite oxidation and concentration by evaporation with minor effects from aqueous ferrous iron oxidation and efflorescent mineral formation.

  20. THE EFFECT OF pH ON THE DIVISION RATE OF THE COCCOLITHOPHORID CRICOSPHAERA ELONGATA(1).

    Science.gov (United States)

    Swift, E; Taylor, W R

    1966-09-01

    The division rate of Cricosphaera elongata was measured as a function of pH in a medium buffered with the CO2 -bicarbonate-carbonate system. The optimum pH for cell division of the coccolithophorid was 7.8. A change of the partial pressure of CO2 in the medium from 0.03 to 5% did not affect the division rate. Between pH 6.4 and 7.8 changes in the bicarbonate concentration from 0.1 to 6.0 mm and carbonate concentration from 0.007 to 0.1 mm did not affect the rate of division. At loiv experimental pH, C. elongata was nonmotile and grew in clumps; at higher pH values, it was motile and solitary. Coccoliths were not found covering C. elongata if calcite was soluble in the medium.

  1. Emulsifier type, metal chelation and pH affect oxidative stability of n-3-enriched emulsions

    DEFF Research Database (Denmark)

    Haahr, Anne-Mette; Jacobsen, Charlotte

    2008-01-01

    -enriched oil-in-water emulsion. The selected food emulsifiers were Tween 80, Citrem, sodium caseinate and lecithin. Lipid oxidation was evaluated by determination of peroxide values and secondary volatile oxidation products. Moreover, the zeta potential and the droplet sizes were determined. Twen resulted...... in the least oxidatively stable emulsions, followed by Citrem. When iron was present, caseinate-stabilized emulsions oxidized slower than lecithin emulsions at pH 3, whereas the opposite was the case at pH 7. Oxidation generally progressed faster at pH 3 than at pH 7, irrespective of the addition of iron. EDTA...... generally reduced oxidation, as evaluated by volatiles formation in all emulsions, irrespective of pH and emulsifier type, except in the lecithin and cascinate emulsions where a pro-oxidative effect was observed for some volatiles. The different effects of the emulsifier types could be related...

  2. Immobilized fluorescent dyes for sensitive pH measurements on enamel surfaces with fiber optics

    Science.gov (United States)

    Rumphorst, A.; Seeger, Stefan; Duschner, H.

    1996-01-01

    Information on the pH directly on surfaces of dental enamel is an important aspect in research on tooth decay. As an alternative to pH-electrodes our approach to the problem is the optical determination of pH by pH sensitive fluorescent dyes immobilized to tooth surfaces. In this study a model for measuring pH either on aminated cellulose substrates or on enamel (in vitro) with a fluorescein type dye is presented. The experimental realization is a fiber optic sensor with a nitrogen-pumped dye laser system and photodiode for the detection of the emitted fluorescence light. The surface pH values in the range between 4 and 7 were derived from the ratios of the excitation bands at 490 nm and 460 nm.

  3. The role of electrolyte pH on phase evolution and magnetic properties of CoFeW codeposited films

    Energy Technology Data Exchange (ETDEWEB)

    Ghaferi, Z., E-mail: Ghaferi_z@yahoo.com [Department of Material Science and Engineering, Shahid Bahonar University of Kerman, 7618868366 Kerman (Iran, Islamic Republic of); Sharafi, S. [Department of Material Science and Engineering, Shahid Bahonar University of Kerman, 7618868366 Kerman (Iran, Islamic Republic of); Bahrololoom, M.E. [Department of Material Science and Engineering, Shiraz University, 7134851154 Shiraz (Iran, Islamic Republic of)

    2016-07-01

    Highlights: • Deposition tends to anomalous-induced fashion at higher pH values. • The structure of the coatings depend on electrolyte pH effectively. • Grain size of two-phase structure films is lower than single-phase solid solutions. • Coercivity of the coatings changed by tungsten content and surface defects. • The highest pH value produced coating with superior magnetic behaviour. - Abstract: In this research, nanocrystalline Co–Fe–W alloy coatings were electrodeposited from a citrate-borate bath. The influence of electrolyte pH on the morphology, microstructure and magnetic properties of these films was also studied. By increasing pH value, the amount of iron content increased from 30 to 55 wt.% which indicates anomalous fashion at higher pH electrolytes. X-ray diffraction patterns showed that the structure of these films depend on electrolyte pH effectively. However, two-phase structure coatings showed smaller average grain size compared with one- phase solid solutions. Vibrating sample magnetometer measurements indicated that the coercivity of the coatings was in the range of 21–76 Oe. However, the highest pH value produced coating with superior magnetic behaviour. Microhardness of the coatings reached its maximum value at about 260HV which is referred to the highest tungsten content.

  4. pH Responsive and Oxidation Resistant Wet Adhesive based on Reversible Catechol-Boronate Complexation.

    Science.gov (United States)

    Narkar, Ameya R; Barker, Brett; Clisch, Matthew; Jiang, Jingfeng; Lee, Bruce P

    2016-08-09

    A smart adhesive capable of binding to a wetted surface was prepared by copolymerizing dopamine methacrylamide (DMA) and 3-acrylamido phenylboronic acid (AAPBA). pH was used to control the oxidation state and the adhesive property of the catechol side chain of DMA and to trigger the catechol-boronate complexation. FTIR spectroscopy confirmed the formation of the complex at pH 9, which was not present at pH 3. The formation of the catechol-boronate complex increased the cross-linking density of the adhesive network. Most notably, the loss modulus values of the adhesive were more than an order of magnitude higher for adhesive incubated at pH 9 when compared to those measured at pH 3. This drastic increase in the viscous dissipation property is attributed to the introduction of reversible complexation into the adhesive network. Based on the Johnson Kendall Roberts (JKR) contact mechanics test, adhesive containing both DMA and AAPBA demonstrated strong interfacial binding properties (work of adhesion (Wadh) = 2000 mJ/m(2)) to borosilicate glass wetted with an acidic solution (pH 3). When the pH was increased to 9, Wadh values (180 mJ/m(2)) decreased by more than an order of magnitude. During successive contact cycles, the adhesive demonstrated the capability to transition reversibly between its adhesive and nonadhesive states with changing pH. Adhesive containing only DMA responded slowly to repeated changes in pH and became progressively oxidized without the protection of boronic acid. Although adhesive containing only AAPBA also demonstrated strong wet adhesion (Wadh ∼ 500 mJ/m(2)), its adhesive properties were not pH responsive. Both DMA and AAPBA are required to fabricate a smart adhesive with tunable and reversible adhesive properties.

  5. Fabrication and characterization of TiO2 coated cone shaped nano-fiber pH sensor

    Science.gov (United States)

    Pathak, A. K.; Bhardwaj, V.; Gangwar, R. K.; De, M.; Singh, V. K.

    2017-03-01

    In the present paper a novel cone shaped nano-fiber (CSNF) pH sensor using multi-mode fiber (MMF) has been fabricated and demonstrated. Three different pH indicators, chlorophenol red, bromothymol blue and cresol red with precursor tetraethyl orthosilicate (TEOS) have been used for fabrication of pH sensing layer. A significant enhancement in sensing properties of pH sensor with TiO2 thin film has been observed. The pH sensor with TiO2 thin film shows the quite high sensitivity (1.16 dBm/pH) as compared to sensor with simple pH coating (0.81 dBm/pH) at 1550 nm with a good linear response. Moreover, the sensor with TiO2 film exhibits fast response time of ∼ 25 s for pH values ranging from 4 to 11 with excellent stability and durability.

  6. Effects of pH and phosphate on glyphosate adsorption to Argentina soils.

    Science.gov (United States)

    De Geronimo, Eduardo; Aparicio, Virginia; Costa, José Luis

    2017-04-01

    Glyphosate is a non-selective, post-emergence herbicide that is widely used in Argentina. Due to the similar molecular structures, glyphosate and phosphate compete for the same adsorption sites in soil. Soil pH has a strong influence in glyphosate and phosphate adsorption since it modifies the net charge of the molecules and, consequently, the force of the electrostatic interaction between these molecules and soil components. Glyphosate adsorption generally decreases as the soil pH was increased, although there were exceptions. In this work, we study the effects of pH and the presence of phosphate on the adsorption of glyphosate on six different types of Argentina soils. Batch equilibrium technique was employed to study the adsorption of glyphosate onto soils at different pH values (from 3 to 9) and phosphate content (0.5 and 1 mM). Stepwise multiple linear regression analysis was applied to obtain a relationship between the sorption parameters and soil properties. The results indicated that Freundlich equations used to simulate glyphosate adsorption isotherms gave high correlation coefficients with Kf values range from 24.9 to 397.4. Clay contents and soil pH were found to be the most significant soil factors affecting the glyphosate adsorption process. The presence of phosphate significantly decreased the adsorption of glyphosate to soils. The Kf values obtained for all six soils decreased a 40% at 0.5 mM of phosphate and a 55% at 1 mM of phosphate. On the other hand, the affinity parameters of glyphosate to soils varied with changes in pH. A general trend of decrease in glyphosate adsorption with increase in pH was observed for all six studied soils. In turn, there appears to be a maximum glyphosate adsorption at pH close to 6 for most soils when the net charge of the molecule at this pH was approximately -1.7.

  7. Simultaneous measurement of intraluminal pressure and pH in the stomach and oesophagus

    Science.gov (United States)

    Lockwood, Knud; Borgeskov, Sven

    1969-01-01

    A short survey is given of the theoretical background for the simultaneous measurement of intraluminal pressure and pH in the oesophagus and stomach as well as the method used in the paper presented. In 20 of 23 patients with symptoms of regurgitation this was sustained by the pH measurement (87%). In only 20% was incompetence demonstrated radiologically. The pH measurement is of especial value in the diagnosis of oesophageal reflux. The value of simultaneous pressure measurements is to ascertain the position of the electrode distally or proximally to the oesophageal hiatus. Thus we suggest that pressure and pH measurements are mandatory in future post-operative follow-up examinations in patients operated upon for hiatal herniae. Images PMID:5348327

  8. Effect of extraction pH on heat-induced aggregation, gelation and microstructure of protein isolate from quinoa (Chenopodium quinoa Willd)

    NARCIS (Netherlands)

    Ruiz, Geraldine Avila; Xiao, Wukai; Boekel, van Tiny; Minor, Marcel; Stieger, Markus

    2016-01-01

    The aim of this study was to determine the influence of extraction pH on heat-induced aggregation, gelation and microstructure of suspensions of protein isolates extracted from quinoa (Chenopodium quinoa Willd). Quinoa seed protein was extracted by alkaline treatment at various pH values (pH 8

  9. Soil pH in fruit trees in relation to specific apple replant disorder (SARD). II. The first five years at Wageningen research plot

    NARCIS (Netherlands)

    Jonkers, H.; Hoestra, H.; Borsboom, O.; Pouwer, A.

    1980-01-01

    Field plots were established with 4 target pH values, viz. 4, 5, 6 and 7, to study the effect of pH on specific apple replant disorder (SARD). The target pH levels were not stable and frequently showed fluctuations. Although no significant differences have been found on tree performance, the develop

  10. Effect of extraction pH on heat-induced aggregation, gelation and microstructure of protein isolate from quinoa (Chenopodium quinoa Willd)

    NARCIS (Netherlands)

    Ruiz, Geraldine Avila; Xiao, Wukai; Boekel, van Tiny; Minor, Marcel; Stieger, Markus

    2016-01-01

    The aim of this study was to determine the influence of extraction pH on heat-induced aggregation, gelation and microstructure of suspensions of protein isolates extracted from quinoa (Chenopodium quinoa Willd). Quinoa seed protein was extracted by alkaline treatment at various pH values (pH 8 (E

  11. Low temperature lignocellulose pretreatment: effects and interactions of pretreatment pH are critical for maximizing enzymatic monosaccharide yields from wheat straw

    DEFF Research Database (Denmark)

    Pedersen, Mads; Johansen, Katja S.; Meyer, Anne S.

    2011-01-01

    C for 10 min. The maximal enzymatic glucose and xylose yields from the solid, pretreated wheat straw fraction were obtained after pretreatments at the most extreme pH values (pH 1 or pH 13) at the maximum pretreatment temperature of 140 degrees C. Surface response models revealed significantly...

  12. Inhibition Effect of pH on the Hatchability of Fasciola Miracidia under Laboratory Conditions

    Directory of Open Access Journals (Sweden)

    Mohammad YAKHCHALI

    2016-03-01

    Full Text Available Background: Fasciolosis, caused by the liver flukes of the genus Fasciola, is one of the most prevalent diseases of domestic livestock and human throughout the world, imposing considerable economic losses. The present study was aimed to assess the effects of different pH values on hatching rate of Fasciola miracidia.Methods: The flukes were isolated from the infected livers of the slaughtered ruminants at the abattoir of Urmia City, Iran, crushed thoroughly and sieved for isola­tion of the Fasciola eggs. The eggs were washed up several times by PBS (0.01N, pH 7.2. They were incubated at different pH values of 7±0.1 (control and 3-9.5 (treatments at 28°C for 16 days.Results: The maximum hatching rate was observed at pH 7 (14.93±0.65%, while no miracidia were hatched at pH 3 and/or pH 9-9.5. There were significant differences between the hatching rate of the treatments and that of the control group.Conclusion: Water pH is proven to be a crucial factor affecting the life cycle of Fasciola and its epidemiology.

  13. Effect of pH on the rheological response of reconstituted gastric mucin

    Directory of Open Access Journals (Sweden)

    Jonathan Argenis Caicedo

    2015-08-01

    Full Text Available The rheological response of reconstituted gastric mucin was studied by time dependent rheological experiments as function of pH. Mucin concentrations of 5% and 10% were prepared in buffer dispersions at pH of 1.15, 2.00, 2.55, 4.00 and 7.67.  The isoelectric point was identified by z-potential between pH 2.00 to 2.55. Dynamic light scattering showed that as pH reduced, a second population of larger mucin aggregates was formed indicating the presence of new structures. Steady shear rheological measurements reflected the pseudoplastic behavior of mucin dispersions and the effect of concentration on viscosity. Creep-recovery measurements were performed on the regenerated mucus at different levels of pH. By creep, it was possible to determine the values of zero-shear-viscosity of mucin suspensions, with higher precision and in a lower experimental time than steady shear measurements. Additionally, it was found that at pH ~1.15, the viscosity of the mucus increased to high values, which is an indicative of a gel-like structure. By recovery experiments, it was possible to find that even the very low viscosities the mucin suspensions at pH ~1.15 possessed a defined elastic character. By the use of a four-element mechanistic viscoelastic model, it was concluded that this elasticity underwent retardation due to the combined effect of viscous and elastic responses.

  14. Origin of the Instability of Octadecylamine Langmuir Monolayer at Low pH.

    Science.gov (United States)

    Avazbaeva, Zaure; Sung, Woongmo; Lee, Jonggwan; Phan, Minh Dinh; Shin, Kwanwoo; Vaknin, David; Kim, Doseok

    2015-12-29

    It has been reported that an octadecylamine (ODA) Langmuir monolayer becomes unstable at low pH values with no measurable surface pressure at around pH 3.5, suggesting significant dissolution of the ODA molecule into the subphase solution (Albrecht, Colloids Surf. A 2006, 284-285, 166-174). However, by lowering the pH further, ODA molecules reoccupy the surface, and a full monolayer is recovered at pH 2.5. Using surface sum-frequency spectroscopy and pressure-area isotherms, it is found that the recovered monolayer at very low pH has a larger area per molecule with many gauche defects in the ODA molecules as compared to that at high pH values. This structural change suggests that the reappearance of the monolayer is due to the adsorbed Cl(-) counterions to the protonated amine groups, leading to partial charge neutralization. This proposition is confirmed by intentionally adding monovalent salts (i.e., NaCl, NaBr, or NaI) to the subphase to recover the monolayer at pH 3.5, in which the detailed structure of the monolayer is confirmed by sum frequency spectra and the adsorbed anions by X-ray reflectivity.

  15. Influence of pH on inhibition of Streptococcus mutans by Streptococcus oligofermentans.

    Science.gov (United States)

    Liu, Ying; Chu, Lei; Wu, Fei; Guo, Lili; Li, Mengci; Wang, Yinghui; Wu, Ligeng

    2014-02-01

    Streptococcus oligofermentans is a novel strain of oral streptococcus that can specifically inhibit the growth of Streptococcus mutans. The aims of this study were to assess the growth of S. oligofermentans and the ability of S. oligofermentans to inhibit growth of Streptococcus mutans at different pH values. Growth inhibition was investigated in vitro using an interspecies competition assay. The 4-aminoantipyine method was used to measure the initial production rate and the total yield of hydrogen peroxide in S. oligofermentans. S. oligofermentans grew best at pH 7.0 and showed the most pronounced inhibitory effect when it was inoculated earlier than S. mutans. In terms of the total yield and the initial production rate of hydrogen peroxide by S. oligofermentans, the effects of the different culture pH values were as follows: pH 7.0 > 6.5 > 6.0 > 7.5 > 5.5 = 8.0 (i.e. there was no significant difference between pH 5.5 and pH 8.0). Environmental pH and the sequence of inoculation significantly affected the ability of S. oligofermentans to inhibit the growth of S. mutans. The degree of inhibition may be attributed to the amount of hydrogen peroxide produced.

  16. Lead forms in urban turfgrass and forest soils as related to organic matter content and pH

    Science.gov (United States)

    Ian D. Yesilonis; Bruce R. James; Richard V. Pouyat; Bahram Momen

    2008-01-01

    Soil pH may influence speciation and extractability of Pb, depending on type of vegetation in urban soil environments. We investigated the relationship between soil pH and Pb extractability at forest and turf grass sites in Baltimore, Maryland. Our two hypotheses were: (1) due to lower pH values in forest soils, more Pb will be in exchangeable forms in forested than in...

  17. Method for ph-controlled fermentation and biogas production

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention is in the field of biomass processing and bioenergy production and facilitates efficient biomass processing and an increased production of renewable energy from processing and anaerobic fermentation of a wide variety of organic materials. In order to control the pH value of ...... of the biomass during processing thereof, a CO 2 containing gas, such as e.g. biogas or flue gas, is added to the biomass present in the buffer tank and/or in the anaerobic digester operably linked to the buffer tank...

  18. Effects of pH and Trace Minerals on Long-Term Starvation of Leuconostoc mesenteroides

    Science.gov (United States)

    Kim, Dong-Shik; Thomas, Steven; Fogler, H. Scott

    2000-01-01

    Laboratory experiments have definitively shown that exopolymer-producing bacteria have the potential to modify the flow of fluids in oil reservoirs to enhance oil production. Once injected into the reservoir, they will be subjected to a wide range of pH values and to starvation resulting from nutrient depletion. For successful field implementation it is necessary to have a fundamental understanding of these effects on the viability of bacteria. This paper addresses the effects of pH and trace minerals on cell viability of Leuconostoc mesenteroides during carbon source depletion. Two different carbon sources were used to grow cells before transferring the cells to starvation conditions: sucrose and a combination of glucose and fructose. These substrates were chosen because L. mesenteroides produces a significant amount of water-insoluble exopolymers (dextran) under sucrose-fed conditions, which may enhance cell survival under harsh conditions. The effects of dextran on the cell viability were tested at different pH values with and without trace minerals. The rate of cell death followed an exponential-decay law for different values of the solution pH. The optimal solution pH for survival was pH 5, whereas cells died rapidly at pH 3 and below and at pH 13 and above. The sucrose-fed cells showed a greater viability than cells fed glucose and fructose for all pH ranges tested. The results indicated that water-insoluble exopolymers help cells survive for longer periods of time under starvation conditions. The effects of trace minerals on cell culturability were tested at two pH values, 4.5 and 7. For both cases, cells showed a greater culturability (smaller decay rate constant) in the presence of trace minerals than without trace minerals. It was also found that the effects of trace minerals on cell culturability were greater for glucose-fructose-fed cells than for sucrose-fed cells. The Michaelis pH function theory was used for comparing the relationships between the

  19. Effect of pH on desorption of CO2 from alkanolamine - rich solvents

    Science.gov (United States)

    Du, Min

    2017-08-01

    Adipic acid was used as a pH regulator, which was added to 0.4 mol/L MEA, DEA and MDEA solvents during CO2 desorption process. It is found that when pH value of the solvents swing between 8-10, CO2 desorption rate enhanced, and energy consumption has declined obviously. This research may have reference significance on optimization of alkanolamine CO2 capture process.

  20. Initiation of lipid autoxidation by ABAP at pH 4-10 in SDS micelles.

    Science.gov (United States)

    Musialik, Malgorzata; Kita, Marcin; Litwinienko, Grzegorz

    2008-02-21

    The rates of radical generation, R(i), by two water soluble initiators: 2,2'-azobis(2-methylpropionamidine) and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], and the lipid soluble 2,2'-azobisisobutyronitrile were measured in an SDS micellar system over a pH range of 4-10. Enhanced values of R(i) at low pH are attributed to Coulombic repulsion of protonated radicals.

  1. Competitive and synergistic effects in pH dependent phosphate adsorption in soils: LCD modeling.

    Science.gov (United States)

    Weng, Liping; Vega, Flora Alonso; Van Riemsdijk, Willem H

    2011-10-01

    The pH dependency of soluble phosphate in soil was measured for six agricultural soils over a pH range of 3-10. A mechanistic model, the LCD (ligand charge distribution) model, was used to simulate this change, which considers phosphate adsorption to metal (hydr)oxides in soils under the influence of natural organic matter (NOM) and polyvalent cations (Ca(2+), Al(3+), and Fe(3+)). For all soils except one, the description in the normal pH range 5-8 is good. For some soils at more extreme pH values (for low P-loading soils at low pH and for high P-loading soils at high pH), the model over predicts soluble P. The calculation shows that adsorption is the major mechanism controlling phosphate solubility in soils, except at high pH in high P-loading soils where precipitation of calcium phosphate may take place. NOM and polyvalent cations have a very strong effect on the concentration level of P. The pattern of pH dependency of soluble P in soils differs greatly from the pH effects on phosphate adsorption to synthetic metal (hydr)oxides in a monocomponent system. According to the LCD model, the pH dependency in soil is mainly caused by the synergistic effects of Ca(2+) adsorption to oxides. Adsorption of Al(3+) to NOM adsorbed plays an important role only at a pH < 4.5. Presence of NOM coating strongly competes with phosphate for the adsorption and is an important factor to consider in modeling phosphate adsorption in natural samples.

  2. Nonlinear friction characteristics between silica surfaces in high pH solution.

    Science.gov (United States)

    Taran, Elena; Kanda, Yoichi; Vakarelski, Ivan U; Higashitani, Ko

    2007-03-15

    Molecular-scale characteristics of friction forces between silica particles and silica wafers in aqueous solutions of the normal (pH 5.6) and high pH (pH 10.6) are investigated, using the lateral force measuring procedure of the atomic force microscope (AFM). Various significant differences of friction characteristics between solutions of normal and high pH's are found. In the case of solutions of normal pH, the friction force increases linearly with increasing loading force, as the Amonton's law for solid bodies indicates. However, in the case of high pH solutions, the increasing rate with the loading force is considerably reduced in the low loading region, but the value increases abruptly above a critical loading force to overcome the magnitude of friction force of normal pH above the region of very high loading. It is very interesting to know that this nonlinear force curve at high pH is independent of the atomic-scale roughness of surfaces, although the magnitude of friction is greatly influenced by the roughness in the case of normal pH. The reason why the friction at high pH is independent of the surface roughness is postulated to be due to the hairy-like layer formed on the silica surface. The existence of hairy-like layers at high pH is proven directly by the dynamic method of normal force measurements with AFM and the thickness is estimated to be at least ca. 1.3 nm.

  3. pH gradient and distribution of streptococci, lactobacilli, prevotellae, and fusobacteria in carious dentine.

    Science.gov (United States)

    Kianoush, Nima; Nguyen, Ky-Anh T; Browne, Gina V; Simonian, Mary; Hunter, Neil

    2014-01-01

    Caries process comprises acidogenic and aciduric bacteria that are responsible for lowering the pH and subsequent destruction of hydroxyapatite matrix in enamel and dentine. The aim of this study was to identify the correlation between the pH gradient of a carious lesion and proportion and distribution of four bacterial genera; lactobacilli, streptococci, prevotellae, and fusobacteria with regard to total load of bacteria. A total of 25 teeth with extensive dentinal caries were sampled in sequential layers. Using quantitative real-time PCR of 16S rRNA gene, we quantified the total load of bacteria as well as the proportion of the above-mentioned genera following pH measurement of each sample with a fine microelectrode. We demonstrated the presence of a pH gradient across the lesion with a strong association between the quantity of lactobacilli and the lowest pH range (pH 4.5-5.0; p = 0.003). Streptococci had a tendency to occupy the most superficial aspect of the carious lesion but showed no correlation to any pH value. Prevotellae showed clear preference for the pH range 5.5-6.0 (p = 0.042). The total representation of these four genera did not reach more than one quarter of the total bacterial load in most carious samples. We revealed differential colonization behavior of bacteria with respect to pH gradient and a lower than expected abundance of lactobacilli and streptococci in established carious lesions. The data indicate the numerical importance of relatively unexplored taxa within the lesion of dentinal caries. The gradient nature of pH in the lesion as well as colonization difference of examined bacterial taxa with reference to pH provides a new insight in regard to conservative caries management.

  4. Partial least square modeling of hydrolysis: analyzing the impacts of pH and acetate

    Institute of Scientific and Technical Information of China (English)

    L(U) Fan; HE Pin-jing; SHAO Li-ming

    2006-01-01

    pH and volatile fatty acids both might affect the further hydrolysis of particulate solid waste, which is the limiting-step of anaerobic digestion. To clarify the individual effects of pH and volatile fatty acids, batch experiments were conducted at fixed pH value (pH 5-9) with or without acetate (20 g/L). The hydrolysis efficiencies of carbohydrate and protein were evaluated by carbon and nitrogen content of solids, amylase activity and proteinase activity. The trend of carbohydrate hydrolysis with pH was not affected by the addition of acetate, following the sequence of pH 7>pH 8>pH 9>pH 6>pH 5; but the inhibition of acetate (20 g/L) was obvious by 10%-60 %. The evolution of residual nitrogen showed that the effect of pH on protein hydrolysis was minor, while the acetate was seriously inhibitory especially at alkali condition by 45%-100 %. The relationship between the factors (pH and acetate) and the response variables was evaluated by partial least square modeling (PLS). The PLS analysis demonstrated that the hydrolysis of carbohydrate was both affected by pH and acetate, with pH the more important factor. Therefore, the inhibition by acetate on carbohydrate hydrolysis was mainly due to the corresponding decline of pH, but the presence of acetate species, while the acetate species was the absolutely important factor for the hydrolysis of protein.

  5. Modeling pH variation in reverse osmosis.

    Science.gov (United States)

    Nir, Oded; Bishop, Noga Fridman; Lahav, Ori; Freger, Viatcheslav

    2015-12-15

    The transport of hydronium and hydroxide ions through reverse osmosis membranes constitutes a unique case of ionic species characterized by uncommonly high permeabilities. Combined with electromigration, this leads to complex behavior of permeate pH, e.g., negative rejection, as often observed for monovalent ions in nanofiltration of salt mixtures. In this work we employed a rigorous phenomenological approach combined with chemical equilibrium to describe the trans-membrane transport of hydronium and hydroxide ions along with salt transport and calculate the resulting permeate pH. Starting from the Nernst-Planck equation, a full non-linear transport equation was derived, for which an approximate solution was proposed based on the analytical solution previously developed for trace ions in a dominant salt. Using the developed approximate equation, transport coefficients were deduced from experimental results obtained using a spiral wound reverse osmosis module operated under varying permeate flux (2-11 μm/s), NaCl feed concentrations (0.04-0.18 M) and feed pH values (5.5-9.0). The approximate equation agreed well with the experimental results, corroborating the finding that diffusion and electromigration, rather than a priori neglected convection, were the major contributors to the transport of hydronium and hydroxide. The approach presented here has the potential to improve the predictive capacity of reverse osmosis transport models for acid-base species, thereby improving process design/control.

  6. Axial offset anomalies and local pH

    Energy Technology Data Exchange (ETDEWEB)

    Tarin, F.; Montes, M. [ENUSA Industrias Avanzadas S.A. Technology and Quality, Madrid (Spain); Izquierdo, J. [IBERDROLA Generacion S.A. Unidad de Tecnologia de Materiales, Madrid (Spain); Garcia-Sanchez, J. [Asociacion Nuclear Asco-Vandellos, A.I.E. Licenciamiento y Combustible, Tarragona (Spain)

    2001-07-01

    Small radial and axial offset anomalies (AOA) in some Spanish PWR-type NPP's, in addition to the knowledge of the existence of similar anomalies in U.S. PWR's, led us in 1993 to study this problem. Important parameters were correlated for a database of plant operating data consisting of six cycles of five different PWR plants (all of them of the Westinghouse 3-loop, 12 ft., 17 x 17 fuel design). One of these cycles (the oldest one) followed the standard constant pH{sub 308} = 7.0, and the remaining ones followed a modified elevated pH control strategy (the pH at EOC is typically 7.4). Only for the oldest cycle that used the standard pH control was the in-core and ex-core axial offset values found to be in good agreement with the predictions, and an anomalous soluble boron curve behavior not observed. (author)

  7. An analysis of concentration of sucrose, endogenous pH, and alteration in the plaque pH on consumption of commonly used liquid pediatric medicines

    Directory of Open Access Journals (Sweden)

    Sunitha S

    2009-03-01

    Full Text Available Background: Many parents are often unaware of the hidden, added sugars in many foods and drinks including pediatric liquid medicines; thus, hidden sugar in the form of pediatric medications has not been focused upon as cariogenic agents. Objective: (i assess concentration of sucrose in six pediatric drugs, (ii determine endogenous pH of these drugs, and (iii estimate drop in the plaque pH in the oral cavity in first 30 minutes after consumption of the drugs. Materials and Methods: Ten adult volunteers with mean age of 22 years were double blinded for the study. Concentration of sucrose was assessed by volumetric method at Department of Chemical Branch of Engineering. Endogenous pH and drop in the plaque pH after consumption of the drugs were assessed using digital pH meter. Statistical analysis: SPSS software was used to assess the pH level at different time intervals and expressed as mean ± SD. Changes in pH were assessed by one-way ANOVA followed by Wilcoxons signed rank test. P-value was set at 0.05. Result: There were varying amounts of fermentable sucrose detected in the drugs; all the drugs were acidic. There is a significant drop of plaque pH after consumption of the drug. Conclusion: These sweeteners along with their low endogenic pH form a high cariogenic formulation. Thus, nonsucrose (noncariogenic or sugar-free medications are needed to be prescribed along with proper oral hygiene care to the children under medication.

  8. Regulation of pH During Amelogenesis.

    Science.gov (United States)

    Lacruz, Rodrigo S; Nanci, Antonio; Kurtz, Ira; Wright, J Timothy; Paine, Michael L

    2010-02-01

    During amelogenesis, extracellular matrix proteins interact with growing hydroxyapatite crystals to create one of the most architecturally complex biological tissues. The process of enamel formation is a unique biomineralizing system characterized first by an increase in crystallite length during the secretory phase of amelogenesis, followed by a vast increase in crystallite width and thickness in the later maturation phase when organic complexes are enzymatically removed. Crystal growth is modulated by changes in the pH of the enamel microenvironment that is critical for proper enamel biomineralization. Whereas the genetic bases for most abnormal enamel phenotypes (amelogenesis imperfecta) are generally associated with mutations to enamel matrix specific genes, mutations to genes involved in pH regulation may result in severely affected enamel structure, highlighting the importance of pH regulation for normal enamel development. This review summarizes the intra- and extracellular mechanisms employed by the enamel-forming cells, ameloblasts, to maintain pH homeostasis and, also, discusses the enamel phenotypes associated with disruptions to genes involved in pH regulation.

  9. Extended-range spectroscopic pH measurement using optimized mixtures of dyes.

    Science.gov (United States)

    Raghuraman, B; Gustavson, G; Van Hal, R E G; Dressaire, E; Zhdaneev, O

    2006-12-01

    The spectroscopic technique for pH measurement is a well-established laboratory technique that can give high-accuracy pH values. Recent studies have shown the advantage of this technique over standard potentiometric methods for pH measurements in fresh water and seawater and also at high temperatures and pressures. However, a limitation of the spectroscopic technique is that a single pH dye is sensitive only over a narrow pH range. We have developed optimized dye mixtures that are both sensitive and accurate over a broad pH range. The measurement is robust and simple, requires a minimum of two wavelengths, and is independent of the volume of the dye mixture added. Optimization of the dye mixture formulation to maximize accuracy in a broad range of pH involves varying both the dye type and its mole fraction and also accounting for spectral noise. This technique has been successfully applied for in situ pH measurements of oilfield formation waters.

  10. The Influence of pH on the Scleroglucan and Scleroglucan/Borax Systems

    Directory of Open Access Journals (Sweden)

    Claudia Mazzuca

    2017-03-01

    Full Text Available The effects that an increase of environmental pH has on the triple helix of scleroglucan (Sclg and on the Sclg/borax hydrogel are reported. Rheological experiments show that the hydrogel is less sensitive to pH increase than Sclg alone, while at pH = 14 a dramatic viscosity decrease takes place for both systems. This effect is evidenced also by the reduced water uptake and anisotropic elongation detected, at pH = 14, by the swelling behaviour of tablets prepared with the Sclg/borax system. On the opposite, a different behaviour was observed with guar gum and locust bean gum tablets, tested as reference polysaccharides. The effect of pH on the structure of Sclg and Sclg/borax was investigated also by means of spectroscopic approaches based on the interaction between Congo red (CR and the Sclg triple helix. Obtained results indicated that the CR absorbance maximum is shifted as a function of pH and by the presence of borax. Principal component analysis allowed very precise identification of the pH value at which the Sclg helix collapses. Molecular dynamics simulations of the Sclg/borax–CR complex indicated that, at physiological pH, only a few ordered configurations are populated, according to the induced circular dichroism (CD spectrum evidence.

  11. The effect of bile reflux on the intragastric pH

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Oblective To observe the effect of bile reflux on the intragastric pH. Methods We used ambulatory intragastric pH monitoring along with simultaneous Bilitec 2000 to measure the pH and absorbance of the mixed gastric juice diluted with bile with increasing bilirubin concentration in vitro and the yellow and clear gastric juice aspirated under endoscopy. In vivo,we studied 20 functional dispepsia patients for 24 h with simultaneous intragastric pH and bilirubin monitoring. Results In vitro dilutions,the absorbance value reached to 0. 900 while the concentration was only 20% ,but when the pH of the solution was more than 4,it′s concentration was already up to 60%. The mean absorbance of the yellow gastric juice(0. 348± 0. 131) was significantly higher than that of the clear juice (0. 008 ± 0. 003)(P<0.05). The pH of 80% yellow gastric juice was less than 4, the percentage was not significantly different from the clear samples (81%) (P>0. 05). The pH showed no correlation with the absorbance in the yellow and clear groungs. Eight of the 12 patients with the spontaneous nocturnal episcodes of alkalinization had simultaneous increase of absorbance,4 of the 8 subjects with no aikalinization had increase of absorbance. Gonclusion In some concentration,bile reflux affect little on the intragastric pH.

  12. Rheological behavior and Ibuprofen delivery applications of pH responsive composite alginate hydrogels.

    Science.gov (United States)

    Jabeen, Suraya; Maswal, Masrat; Chat, Oyais Ahmad; Rather, Ghulam Mohammad; Dar, Aijaz Ahmad

    2016-03-01

    Synthesis and structural characterization of hydrogels composed of sodium alginate, polyethylene oxide and acrylic acid with cyclodextrin as the hydrocolloid prepared at different pH values is presented. The hydrogels synthesized show significant variations in rheological properties, drug encapsulation capability and release kinetics. The hydrogels prepared at lower pH (pH 1) are more elastic, have high tensile strength and remain almost unaffected by varying temperature or frequency. Further, their Ibuprofen encapsulation capacity is low and releases it slowly. The hydrogel prepared at neutral pH (pH 7) is viscoelastic, thermo-reversible and also exhibits sol-gel transition on applying frequency and changing temperature. It shows highest Ibuprofen encapsulation capacity and also optimum drug release kinetics. The hydrogel prepared at higher pH (pH 12) is more viscous, has low tensile strength, is unstable to change in temperature and has fast drug release rate. The study highlights the pH responsiveness of three composite alginate hydrogels prepared under different conditions to be employed in drug delivery applications.

  13. Combination effect of pH and acetate on enzymatic cellulose hydrolysis

    Institute of Scientific and Technical Information of China (English)

    ROMSAIYUD Angsana; SONGKASIRI Warinthom; NOPHARATANA Annop; CHAIPRASERT Pawinee

    2009-01-01

    The productivity and efficiency of cellulase are significant in cellulose hydrolysis. With the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system is reduced. Therefore, this study will find out how the pH and the amount of acetate influence the enzymatic hydrolysis of cellulose. The effects of pH and acetate on cellulase produced from Bacillus coagulans were studied at various pH 5-8, and acetate concentrations (0-60 mmol/L). A batch kinetic model for enzymatic cellulose hydrolysis was constructed from experimental data and performed. The base hypothesis was as follows: the rates of enzymatic cellulose hydrolysis rely on pH and acetate concentration. The results showed that the suitable pH range for cellulase production and cellulose hydrolysis (represents efficiency of cellulase) was 2.6-7.5, and 5.3-8.3, respectively. Moreover, acetate in the culture medium had an effect on cellulase production (K1= 49.50 mmol/L, n=1.7) less than cellulose hydrolysis (K1=37.85 mmol/L, n=2.0). The results indicated that both the pH of suspension and acidogenic products influence the enzymatic hydrolysis of cellulose in an anaerobic environment. To enhance the cellulose hydrolysis rate, the accumulated acetate concentration should be lower than 25 mmol/L, and pH should be maintained at 7.

  14. Metal toxicity to freshwater organisms as a function of pH: A meta-analysis.

    Science.gov (United States)

    Wang, Zhen; Meador, James P; Leung, Kenneth M Y

    2016-02-01

    Acidification caused by climate change and seasonal fluctuation can have profound implications for chemical toxicity to freshwater organisms. The present study aims to address this challenging issue through a comprehensive meta-analysis by comparing acute median lethal or effect concentration data (LC50 or EC50) for 10 metals and metalloids for various freshwater species obtained at different pH values. Our results revealed that element toxicity generally follows three different models, including Model-I: decreasing toxicity with increasing pH, Model-II: increasing toxicity with increasing pH, and Model-III: minimal toxicity at intermediate (optimal) pH (pH(opt)) with increasing toxicity as pH increases or decreases from pH(opt). We further examined these observations by constructing pH-dependent species sensitivity distributions (SSDs). The results indicated that the 10(th) percentile hazardous concentrations (HC10s) for copper, lead, selenium and silver generally exhibited a positive linear relationship with pH, following the Model-I. The ability to accurately predict toxicity of elements to biota in natural waters as a function of pH may be limited, however, the pH-dependent SSD approach presented in this study facilitates and helps characterize the role of pH in water quality guidelines and ecological risk assessment.

  15. A novel acidic pH fluorescent probe based on a benzothiazole derivative.

    Science.gov (United States)

    Ma, Qiujuan; Li, Xian; Feng, Suxiang; Liang, Beibei; Zhou, Tiqiang; Xu, Min; Ma, Zhuoyi

    2017-04-15

    A novel acidic pH fluorescent probe 1 based on a benzothiazole derivative has been designed, synthesized and developed. The linear response range covers the acidic pH range from 3.44 to 6.46, which is valuable for pH researches in acidic environment. The evaluated pKa value of the probe 1 is 4.23. The fluorescence enhancement of the studied probe 1 with an increase in hydrogen ions concentration is based on the hindering of enhanced photo-induced electron transfer (PET) process. Moreover, the pH sensor possesses a highly selective response to H(+) in the presence of metal ions, anions and other bioactive small molecules which would be interfere with its fluorescent pH response. Furthermore, the probe 1 responds to acidic pH with short response time that was less than 1min. The probe 1 has been successfully applied to confocal fluorescence imaging in live HeLa cells and can selectively stain lysosomes. All of such good properties prove it can be used to monitoring pH fluctuations in acidic environment with high sensitivity, pH dependence and short response time.

  16. A nocturnal decline of salivary pH associated with airway hyperresponsiveness in asthma.

    Science.gov (United States)

    Watanabe, Masanari; Sano, Hiroyuki; Tomita, Katsuyuki; Yamasaki, Akira; Kurai, Jun; Hasegawa, Yasuyuki; Igishi, Tadashi; Okazaki, Ryota; Tohda, Yuji; Burioka, Naoto; Shimizu, Eiji

    2010-08-01

    Salivary pH is associated with esophageal acid reflux and neutralization of esophageal acid. In this study, we assessed the association between nocturnal decline of salivary pH and airway hyperresponsiveness. Salivary pH was serially assessed in 9 patients with mild asthma (7 men and 2 women; mean age 33.3 years; mean %predicted FEV(1.0) 89.4%) and 10 healthy volunteers (6 men and 4 women; mean age 31.2 years) using a pH indicator tape. The buffering capacity of saliva was defined as the median effective dose (ED(50)) for acidification of saliva with 0.01 N HCl, and airway responsiveness was defined as the dose of methacholine producing a 35% fall in Grs (PD(35)-Grs). There was a significant correlation between the values obtained from the pH indicator tape and those obtained from the electrometric pH meter. Using the indicator tape for sequential monitoring, we observed a nocturnal fall (ΔpH) in salivary pH in all subjects. A significant correlation was found between airway hyperresponsiveness (PD(35)-Grs) and either ΔpH or ED(50) in mildly asthmatic patients. Vagal reflux dysfunction might contribute to nocturnal salivary pH as well as to airway hyperresponsiveness in mild asthmatics.

  17. pH Dependence of microbe sterilization by cationic antimicrobial peptides.

    Science.gov (United States)

    Walkenhorst, William F; Klein, J Wolfgang; Vo, Phuong; Wimley, William C

    2013-07-01

    We recently described a family of cationic antimicrobial peptides (CAMPs) selected from a combinatorial library that exhibited potent, broad-spectrum activity at neutral pH and low ionic strength. To further delimit the utility and activity profiles of these peptides, we investigated the effects of solution conditions, such as pH and ionic strength, on the efficacy of the peptide antimicrobials against a panel of microorganisms. Peptide minimum sterilizing concentrations (MSCs) varied linearly with pH for each subtype within our family of CAMPs for all organisms tested. The peptides were much less effective against Gram-negative bacteria at high pH, consistent with a decrease in net positive charge on the peptides. A similar trend was observed for the fungus Candida albicans. Surprisingly, the opposite pH trend was observed with the Gram-positive Staphylococcus aureus. In addition, an additive ionic strength effect was observed with increasing buffer strengths at identical pH values. The extreme difference in the observed pH behavior between Gram-negative and Gram-positive organisms is attributed to the presence of native charged molecules in the much thicker peptidoglycan layer of the Gram-positive organism. The novel species-specific effects of pH observed here have important implications for applications using CAMPs and for the design of novel CAMPs.

  18. Response of the cytoplasmic and membrane proteome of Corynebacterium glutamicum ATCC 13032 to pH changes

    OpenAIRE

    Poetsch Ansgar; Barreiro Carlos; Schluesener Daniela; Barriuso-Iglesias Mónica; Martín Juan F

    2008-01-01

    Abstract Background C. glutamicum has traditionally been grown in neutral-pH media for amino acid production, but in a previous article we reported that this microorganism is a moderate alkaliphile since it grows optimally at pH 7.0–9.0, as shown in fermentor studies under tightly controlled pH conditions. We determined the best pH values to study differential expression of several genes after acidic or basic pH conditions (pH 6.0 for acidic expression and pH 9.0 for alkaline expression). Thu...

  19. Simple adaptive pH control in bioreactors using gain-scheduling methods.

    Science.gov (United States)

    Gnoth, S; Kuprijanov, A; Simutis, R; Lübbert, A

    2010-01-01

    A simple well-performing adaptive control technique for pH control in fermentations of recombinant protein production processes is described and its design procedure is explained. First, the entire control algorithm was simulated and parameterized. Afterwards it was tested in real cultivation processes. The results show that this simple technique leads to significant reductions in the fluctuations of the pH values in microbial cultures at a minimum of expenditures. The signal-to-noise ratio and thus the information captured by the pH signal were increased by about an order of magnitude. This leads to a substantial improvement in the noise of many other process signals that are used to monitor and control the process. For instance, respiratory off-gas data of CO(2) and its derived carbon dioxide production rate signals from the cultures carry much less noise as compared to those values obtained with conventional pH control. Detailed process analysis revealed that even very small pH jumps of 0.03 values during the fermentation were shown to result in pronounced deflections in CO(2)-volume fraction of 8% (peak to peak). The proposed controller, maintaining the pH within the interval of 0.01 around the setpoint, reduces the noise considerably.

  20. [Impacts of pH and surfactants on adsorption behaviors of norfloxacin on marine sediments].

    Science.gov (United States)

    Pang, Hui-Ling; Yang, Gui-Peng; Gao, Xian-Chi; Cao, Xiao-Yan

    2012-01-01

    The adsorption behaviors of norfloxacin (NOR) on marine sediments at different pH values and in the presence of four different surfactants were systematically investigated by a batch equilibrium method. The results indicated that Freundlich adsorption isotherms fitted the adsorption behavior of NOR on marine sediments very well at different pH values. The Freundlich constant K(F) and the equilibrium adsorption amount of NOR reduced with the increase of pH values, and the minimum appeared at pH 8.10. The results suggested that cation exchange was the main adsorption mechanism of NOR at pH 6.01, while Van der Waals' force, hydrophobic effects, electrostatic force were the major adsorption mechanism of NOR on marine sediments at pH 8.10. The adsorption process fitted well with pseudo-second-order kinetic equations with the addition of surfactants. Our study also indicated that the addition of surfactants had the significant influence on the saturated adsorption amount of adsorption of NOR. The equilibrium adsorption amount (Q(e)) of NOR exhibited the following sequence: Q(e) (Tween80) < Q(e) (Tween20)

  1. Does pH influence soil hydro-mechanical properties?

    Science.gov (United States)

    Chaplain, V.; Défossez, P.; Delarue, G.; Dexter, A. R.; Richard, G.; Tessier, D.

    2009-04-01

    Does pH influence soil hydro-mechanical properties ? V. Chaplain1, P. Défossez2, G. Delarue1, A.R. Dexter3, G. Richard3 and D. Tessier1. 1 UR INRA PESSAC RD 10, F-78026 Versailles cedex 2 UMR INRA/URCA FARE, 2 Esplanade Roland Garros, BP 224 F-51686 Reims cedex 2 3 UR INRA Sols 2163 Avenue de la Pomme de Pin - CS 40001 ARDON F-45075 Orléans Cedex 2 Corresponding author : chaplain@versailles.inra.fr Structure of soils and its dynamic, physico-chemistry of the interface are of a great importance in the fate of organic pollutants because it governs the accessibility of pollutants to micro-organisms. The soil structure of soils is related to physical parameters (texture, density, water content) but the physico-chemical properties of the interface is not considered. In this study we performed hydro-mechanical measurements on soil samples taken from the 42-plot long-term experiment in Versailles. Indeed six plots were selected to cover a large range of pH values from acid (3.5) to alkaline (8.2) due to the repeated application of fertilizers. Soils were taken in the 0-20 cm and in the 30-35 cm layer out of the ploughed zone. All soils had similar texture and composition with low organic carbon. Therefore pH changes the surface charges and hydrophobicity that are implied in aggregation process. The two layers had the same pH values. The precompression stress Pc and the compression index Cc were derived from confined compression tests performed on remoulded soil samples (density 1.45 g/cm3) at saturation. Results shows that the precompression stress increased at pH lower than 4. In acid case, precompression stress was higher in subsoil. This increase of Pc was attributed to the hydrophobicity due in part to the condensation of charges probably sensitive to the humectation/dessication processes.

  2. Pattern recognition of ocean pH

    Science.gov (United States)

    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.

  3. A semipermeable enzymatic nanoreactor as an efficient modulator for reversible pH regulation

    Science.gov (United States)

    Huang, Yanyan; Lin, Youhui; Ran, Xiang; Ren, Jinsong; Qu, Xiaogang

    2014-09-01

    Here we propose a new concept for the fabrication of a semipermeable enzymatic nanoreactor as an efficient modulator to reversibly switch the pH of an aqueous environment. We used amino-functionalized, expanded mesoporous silica nanoparticles (EMSN) as a model nanocarrier to load enzymes. In order to protect enzymes from the interference of a complicated environment, polyelectrolyte multilayers (PEMs) were coated on the surface of the EMSN through layer by layer (LbL) assembly. These PEMs can serve as semipermeable membranes, allowing small molecules to diffuse in and out freely while trapping the enzymes in the nanoreactors. Compared with traditional electrochemical stimulation or optical control methods, our enzymatic regulation platform is easy to operate without complicated instruments. In addition, this system can cover a wide range of pH values and conveniently regulate pH values by simply controlling the concentrations of catalysts or reactants. Meanwhile, this strategy could be generalized to other enzymes or nanocarriers to achieve reversible pH regulation for different purposes. The switched pH values can be implemented for the modulation of the conformational changes of nucleic acids and activation of the charge conversion in drug delivery applications.Here we propose a new concept for the fabrication of a semipermeable enzymatic nanoreactor as an efficient modulator to reversibly switch the pH of an aqueous environment. We used amino-functionalized, expanded mesoporous silica nanoparticles (EMSN) as a model nanocarrier to load enzymes. In order to protect enzymes from the interference of a complicated environment, polyelectrolyte multilayers (PEMs) were coated on the surface of the EMSN through layer by layer (LbL) assembly. These PEMs can serve as semipermeable membranes, allowing small molecules to diffuse in and out freely while trapping the enzymes in the nanoreactors. Compared with traditional electrochemical stimulation or optical control methods

  4. Increased osteoblast viability at alkaline pH in vitro provides a new perspective on bone regeneration

    Directory of Open Access Journals (Sweden)

    Anne-Marie Galow

    2017-07-01

    Full Text Available We investigated the effects of alkaline pH on developing osteoblasts. Cells of the osteoblast-like cell line MC3T3-E1 were initially cultured for six days in HEPES-buffered media with pH ranging from 7.2 to 9.0. Cell count, cellular WST-1 metabolism, and ATP content were analyzed. The three parameters showed a pH optimum around pH 8.4, exceeding the recommended buffer range of HEPES at the alkaline flank. Therefore, only pH 7.2, 7.4, 7.8, and 8.4 media were used in more elaborate, daily investigations to reduce the effects of pH change within the pH control intervals of 24 h. All parameters exhibited similar pH behaviors, roughly showing increases to 130% and 230% at pH 7.8 and 8.4, as well as decreases to 70% at pH 7.2 when using the pH 7.4 data for reference. To characterize cell differentiation and osteoblastic cell function, cells were cultured at pH 7.4 and under alkaline conditions at pH 7.8 and 8.4 for 14 days. Gene expression and mineralization were evaluated using microarray technology and Alizarin staining. Under alkaline conditions, ATF4, a regulator for terminal differentiation and function as well as DMP1, a potential marker for the transition of osteoblasts into osteocytes, were significantly upregulated, hinting at an accelerated differentiation process. After 21 days, significant mineralization was only detected at alkaline pH. We conclude that elevated pH is beneficial for the cultivation of bone cells and may also provide therapeutic value in bone regeneration therapies.

  5. pH preference and avoidance responses of adult brook trout Salvelinus fontinalis and brown trout Salmo trutta.

    Science.gov (United States)

    Fost, B A; Ferreri, C P

    2015-03-01

    The pH preferred and avoided by wild, adult brook trout Salvelinus fontinalis and brown trout Salmo trutta was examined in a series a laboratory tests using gradual and steep-gradient flow-through aquaria. The results were compared with those published for the observed segregation patterns of juvenile S. fontinalis and S. trutta in Pennsylvania streams. The adult S. trutta tested showed a preference for pH 4·0 while adult S. fontinalis did not prefer any pH within the range tested. Salmo trutta are not found in Pennsylvania streams with a base-flow pH pH well above 4·0. Adult S. trutta displayed a lack of avoidance at pH below 5·0, as also reported earlier for juveniles. The avoidance pH of wild, adult S. fontinalis (between pH 5·5 and 6·0) and S. trutta (between pH 6·5 and 7·0) did not differ appreciably from earlier study results for the avoidance pH of juvenile S. fontinalis and S. trutta. A comparison of c.i. around these avoidance estimates indicates that avoidance pH is similar among adult S. fontinalis and S. trutta in this study. The limited overlap of c.i. for avoidance pH values for the two species, however, suggests that some S. trutta will display avoidance at a higher pH when S. fontinalis will not. The resu