WorldWideScience

Sample records for dipicolinic acid-based mueller

  1. Dipicolinate complexes of main group metals with hydrazinium cation

    Indian Academy of Sciences (India)

    Unknown

    Some new coordination complexes of hydrazinium main group metal dipicolinate hydrates of formulae ... dipicolinate dianions and non-coordinating hydrazinium cations. Conductance measurements ... group metals, and the ability of dip2– to function as a tridentate ligand, we expect to find anionic complexes of the type ...

  2. Gel phase in hydrated calcium dipicolinate

    Science.gov (United States)

    Rajak, Pankaj; Mishra, Ankit; Sheng, Chunyang; Tiwari, Subodh; Krishnamoorthy, Aravind; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya

    2017-11-01

    The mineralization of dipicolinic acid (DPA) molecules in bacterial spore cores with Ca2+ ions to form Ca-DPA is critical to the wet-heat resistance of spores. This resistance to "wet-heat" also depends on the physical properties of water and DPA in the hydrated Ca-DPA-rich protoplasm. Using reactive molecular dynamics simulations, we have determined the phase diagram of hydrated Ca-DPA as a function of temperature and water concentration, which shows the existence of a gel phase along with distinct solid-gel and gel-liquid phase transitions. Simulations reveal monotonically decreasing solid-gel-liquid transition temperatures with increasing hydration, which explains the experimental trend of wet-heat resistance of bacterial spores. Our observation of different phases of water also reconciles previous conflicting experimental findings on the state of water in bacterial spores. Further comparison with an unmineralized hydrated DPA system allows us to quantify the importance of Ca mineralization in decreasing diffusivity and increasing the heat resistance of the spore.

  3. Synthesis, structure and magnetism of manganese and iron dipicolinates with N,N '-donor ligands

    Czech Academy of Sciences Publication Activity Database

    Uhrecký, Róbert; Svoboda, I.; Růžičková, Z.; Koman, M.; Dlháň, L.; Pavlík, J.; Moncol, J.; Boca, R.

    2015-01-01

    Roč. 425, JAN (2015), s. 134-144 ISSN 0020-1693 Institutional support: RVO:61388980 Keywords : Manganese * Iron * Dipicolinate complexes * Crystal structure * Magnetism Subject RIV: CA - Inorganic Chemistry Impact factor: 1.918, year: 2015

  4. Determination of uranium by direct titration with dipicolinic acid

    International Nuclear Information System (INIS)

    Baumann, E.W.

    1984-01-01

    Direct titration of uranium with dipicolinic acid, in the presence of Arsenazo I, is a simple, precise, and accurate method for uranium determination. The method is particularly attractive because it can be totally automated. Detecting the end point (color change from blue to pink) depends on the concentration range. For the Micro Method (1 to 20 ppM U in the solution titrated), the gradual color change is monitored spectrophotometrically. For the Macro Method (20 to 300 ppM), the end point is determined either visually or spectrophotometrically. The spectrophotometric end point is computed by fitting the titration curve. The relative standard deviation is +-1 to 3% for the Micro Method and +-0.3% for the Macro Method

  5. Parallel decompositions of Mueller matrices and polarimetric subtraction

    Directory of Open Access Journals (Sweden)

    Gil J.J.

    2010-06-01

    Full Text Available From a general formulation of the physically realizable parallel decompositions of the Mueller matrix M of a given depolarizing system, a procedure for determining the set of pure Mueller matrices susceptible to be subtracted from M is presented. This procedure provides a way to check if a given pure Mueller matrix N can be subtracted from M or not. If this check is positive, the value of the relative cross section of the subtracted component is also determined.

  6. Beetroot-Pigment-Derived Colorimetric Sensor for Detection of Calcium Dipicolinate in Bacterial Spores

    Science.gov (United States)

    Gonçalves, Letícia Christina Pires; Da Silva, Sandra Maria; DeRose, Paul C.; Ando, Rômulo Augusto; Bastos, Erick Leite

    2013-01-01

    In this proof-of-concept study, we describe the use of the main red beet pigment betanin for the quantification of calcium dipicolinate in bacterial spores, including Bacillus anthracis. In the presence of europium(III) ions, betanin is converted to a water-soluble, non-luminescent orange 1∶1 complex with a stability constant of 1.4×105 L mol–1. The addition of calcium dipicolinate, largely found in bacterial spores, changes the color of the aqueous solution of [Eu(Bn)+] from orange to magenta. The limit of detection (LOD) of calcium dipicolinate is around 2.0×10–6 mol L–1 and the LOD determined for both spores, B. cereus and B. anthracis, is (1.1±0.3)×106 spores mL–1. This simple, green, fast and low cost colorimetric assay was selective for calcium dipicolinate when compared to several analogous compounds. The importance of this work relies on the potential use of betalains, raw natural pigments, as colorimetric sensors for biological applications. PMID:24019934

  7. Mueller-Navelet jets at the LHC

    CERN Document Server

    Ducloué, B.; Wallon, S.

    2015-01-01

    We report on our NLL BFKL studies of Mueller-Navelet jets. We first perform a complete NLL BFKL analysis supplemented by a BLM renormalization scale fixing procedure, which is successfully compared with recent CMS data. Second, we argue for the need of a measurement of an asymmetric jet configuration in order to perform a valuable comparison with fixed order approaches. Third, we predict that the energy-momentum violation is rather tiny in the NLL BFKL approach, for an asymmetric jet configuration. Finally, we argue that the double parton scattering contribution is negligible in the kinematics of actual CMS measurements.

  8. Experimental evidence for partial spatial coherence in imaging Mueller polarimetry.

    Science.gov (United States)

    Ossikovski, Razvigor; Arteaga, Oriol; Yoo, Sang Hyuk; Garcia-Caurel, Enric; Hingerl, Kurt

    2017-11-15

    We demonstrate experimentally the validity of the partial spatial coherence formalism in Mueller polarimetry and show that, in a finite spatial resolution experiment, the measured response is obtained through convolving the theoretical one with the instrument function. The reported results are of primary importance for Mueller imaging systems.

  9. Evaluation of Double-Disk Potentiation and Disk Potentiation Tests Using Dipicolinic Acid for Detection of Metallo-β-Lactamase-Producing Pseudomonas spp. and Acinetobacter spp.

    Science.gov (United States)

    Yong, Dongeun; Lee, Yangsoon; Jeong, Seok Hoon; Lee, Kyungwon

    2012-01-01

    Accurate detection of metallo-β-lactamase (MBL)-producing Pseudomonas spp. and Acinetobacter spp. became very important with the increasing prevalence of carbapenem-nonsusceptible clinical isolates. The performance of phenotypic MBL detection methods may depend on the types of MBL and the characteristics of the isolates. A high false-positive rate is a problem with EDTA-based MBL detection methods. We evaluated the performance of double-disk potentiation tests (DDPTs) and disk potentiation tests (DPTs) with dipicolinic acid (DPA) using 44 isolates of Pseudomonas spp. and Acinetobacter spp. producing IMP-1-like, VIM-2-like, and SIM-1 type MBLs. Also, we characterized P. aeruginosa isolates with positive imipenem (IPM)-DPA DDPT, but negative meropenem (MEM)-DPA DDPT, and determined possibility of improving a DDPT by using MacConkey agar. Among five different DDPT methods, the IPM-DPA 250-μg method showed the highest sensitivity (97.7%) and specificity (100%). Among four DPT tests, the highest sensitivity (100%) was shown by the IPM-EDTA 1,900-μg disk method, but the specificity was very low (11.4%). Five of six P. aeruginosa isolates with false-negative DDPTs with MEM-DPA 250-μg disks carried blaIMP-6, and the high level resistance to MEM (MIC ≥ 512 μg/ml) was reduced by the presence of phenylalanine arginine β-naphtylamide. Improvement of DDPTs was observed when MacConkey agar was used instead of Mueller-Hinton agar. In conclusion, DPA is a better MBL inhibitor than EDTA for detection of Pseudomonas spp. and Acinetobacter spp. with IMP-1-like, VIM-2-like, and SIM-1-type MBLs. In DPA DDPTs, IPM disks perform better than MEM disks when the isolates are highly resistant to MEM due to the overexpression of efflux pumps. PMID:22837321

  10. Mueller Navelet jets at LHC - complete NLL BFKL calculation

    International Nuclear Information System (INIS)

    Colferai, Dimitri; Schwennsen, Florian; Szymanowski, Lech; Ecole Polytechnique, CNRS, Palaiseau; Wallon, Samuel; UPMC Univ. Paris 06

    2010-03-01

    We calculate cross section and azimuthal decorrelation of Mueller Navelet jets at the LHC in the complete next-lo-leading order BFKL framework, i.e. including next-to-leading corrections to the Green's function as well as next-to-leading corrections to the Mueller Navelet vertices. The obtained results for standard observables proposed for studies of Mueller Navelet jets show that both sources of corrections are of equal, big importance for final magnitude and final behavior of observables. The astonishing conclusion of our analysis is that the observables obtained within the complete next-lo-leading order BFKL framework of the present paper are quite similar to the same observables obtained within next-to-leading logarithm DGLAP type treatment. This fact sheds doubts on general belief that the studies of Mueller Navelet jets at the LHC will lead to clear discrimination between the BFKL and the DGLAP dynamics. (orig.)

  11. Mueller Navelet jets at LHC - complete NLL BFKL calculation

    Energy Technology Data Exchange (ETDEWEB)

    Colferai, Dimitri [Firenze Univ. (Italy). Dipt. di Fisica; INFN, Florence (Italy); Schwennsen, Florian [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Szymanowski, Lech [Soltan Inst. for Nuclear Studies, Warsaw (Poland); Ecole Polytechnique, CNRS, Palaiseau (France). CPHT; Wallon, Samuel [Paris-Sud Univ., CNRS, Orsay (France). LPT; UPMC Univ. Paris 06 (France). Faculte de Physique

    2010-03-15

    We calculate cross section and azimuthal decorrelation of Mueller Navelet jets at the LHC in the complete next-lo-leading order BFKL framework, i.e. including next-to-leading corrections to the Green's function as well as next-to-leading corrections to the Mueller Navelet vertices. The obtained results for standard observables proposed for studies of Mueller Navelet jets show that both sources of corrections are of equal, big importance for final magnitude and final behavior of observables. The astonishing conclusion of our analysis is that the observables obtained within the complete next-lo-leading order BFKL framework of the present paper are quite similar to the same observables obtained within next-to-leading logarithm DGLAP type treatment. This fact sheds doubts on general belief that the studies of Mueller Navelet jets at the LHC will lead to clear discrimination between the BFKL and the DGLAP dynamics. (orig.)

  12. Mueller matrix characterization of porous media in visible

    Directory of Open Access Journals (Sweden)

    S. Savenkov

    2011-09-01

    Full Text Available In this paper, we apply Mueller polarimetry to study different samples of porous media compacted as tablets from a pharmaceutical excipient microcrystalline cellulose. We measured the Mueller matrices of the samples with the home made polarimeter using a He-Ne laser (0.63 μm. We show that polarization entropy manifests the highest sensitivity to the porosity allowing to identify the tablets of different porosities.

  13. Modulus design multiwavelength polarization microscope for transmission Mueller matrix imaging.

    Science.gov (United States)

    Zhou, Jialing; He, Honghui; Chen, Zhenhua; Wang, Ye; Ma, Hui

    2018-01-01

    We have developed a polarization microscope based on a commercial transmission microscope. We replace the halogen light source by a collimated LED light source module of six different colors. We use achromatic polarized optical elements that can cover the six different wavelength ranges in the polarization state generator (PSG) and polarization state analyzer (PSA) modules. The dual-rotating wave plate method is used to measure the Mueller matrix of samples, which requires the simultaneous rotation of the two quarter-wave plates in both PSG and PSA at certain angular steps. A scientific CCD detector is used as the image receiving module. A LabView-based software is developed to control the rotation angels of the wave plates and the exposure time of the detector to allow the system to run fully automatically in preprogrammed schedules. Standard samples, such as air, polarizers, and quarter-wave plates, are used to calibrate the intrinsic Mueller matrix of optical components, such as the objectives, using the eigenvalue calibration method. Errors due to the images walk-off in the PSA are studied. Errors in the Mueller matrices are below 0.01 using air and polarizer as standard samples. Data analysis based on Mueller matrix transformation and Mueller matrix polarization decomposition is used to demonstrate the potential application of this microscope in pathological diagnosis. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  14. Robust overlay metrology with differential Mueller matrix calculus.

    Science.gov (United States)

    Chen, Xiuguo; Gu, Honggang; Jiang, Hao; Zhang, Chuanwei; Liu, Shiyuan

    2017-04-17

    Overlay control is of vital importance to good device performances in semiconductor manufacturing. In this work, the differential Mueller matrix calculus is introduced to investigate the Mueller matrices of double-patterned gratings with overlay displacements, which helps to reveal six elementary optical properties hidden in the Mueller matrices. We find and demonstrate that, among these six elementary optical properties, the linear birefringence and dichroism, LB' and LD', along the ± 45° axes show a linear response to the overlay displacement and are zero when the overlay displacement is absent at any conical mounting. Although the elements from the two 2 × 2 off-diagonal blocks of the Mueller matrix have a similar property to LB' and LD', as reported in the literature, we demonstrate that it is only valid at a special conical mounting with the plane of incidence parallel to grating lines. The better property of LB' and LD' than the Mueller matrix elements of the off-diagonal blocks in the presence of overlay displacement verifies them to be a more robust indicator for the diffraction-based overlay metrology.

  15. Modulus design multiwavelength polarization microscope for transmission Mueller matrix imaging

    Science.gov (United States)

    Zhou, Jialing; He, Honghui; Chen, Zhenhua; Wang, Ye; Ma, Hui

    2018-01-01

    We have developed a polarization microscope based on a commercial transmission microscope. We replace the halogen light source by a collimated LED light source module of six different colors. We use achromatic polarized optical elements that can cover the six different wavelength ranges in the polarization state generator (PSG) and polarization state analyzer (PSA) modules. The dual-rotating wave plate method is used to measure the Mueller matrix of samples, which requires the simultaneous rotation of the two quarter-wave plates in both PSG and PSA at certain angular steps. A scientific CCD detector is used as the image receiving module. A LabView-based software is developed to control the rotation angels of the wave plates and the exposure time of the detector to allow the system to run fully automatically in preprogrammed schedules. Standard samples, such as air, polarizers, and quarter-wave plates, are used to calibrate the intrinsic Mueller matrix of optical components, such as the objectives, using the eigenvalue calibration method. Errors due to the images walk-off in the PSA are studied. Errors in the Mueller matrices are below 0.01 using air and polarizer as standard samples. Data analysis based on Mueller matrix transformation and Mueller matrix polarization decomposition is used to demonstrate the potential application of this microscope in pathological diagnosis.

  16. Sudakov resummations in Mueller-Navelet dijet production

    International Nuclear Information System (INIS)

    Mueller, A.H.; Szymanowski, Lech; Wallon, Samuel; Xiao, Bo-Wen; Yuan, Feng

    2016-01-01

    In high energy hadron-hadron collisions, dijet production with large rapidity separation proposed by Mueller and Navelet, is one of the most interesting processes which can help us to directly access the well-known Balitsky-Fadin-Kuraev-Lipatov evolution dynamics. The objective of this work is to study the Sudakov resummation of Mueller-Navelet jets. Through the one-loop calculation, Sudakov type logarithms are obtained for this process when the produced dijets are almost back-to-back. These results could play an important role in the phenomenological study of dijet correlations with large rapidity separation at the LHC.

  17. Near-infrared Mueller matrix imaging for colonic cancer detection

    Science.gov (United States)

    Wang, Jianfeng; Zheng, Wei; Lin, Kan; Huang, Zhiwei

    2016-03-01

    Mueller matrix imaging along with polar decomposition method was employed for the colonic cancer detection by polarized light in the near-infrared spectral range (700-1100 nm). A high-speed (colonic tissues (i.e., normal and caner) were acquired. Polar decomposition was further implemented on the 16 images to derive the diattentuation, depolarization, and the retardance images. The decomposed images showed clear margin between the normal and cancerous colon tissue samples. The work shows the potential of near-infrared Mueller matrix imaging for the early diagnosis and detection of malignant lesions in the colon.

  18. Sudakov resummations in Mueller-Navelet dijet production

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, A.H. [Department of Physics, Columbia University,New York, NY 10027 (United States); Szymanowski, Lech [National Centre for Nuclear Research (NCBJ),Warsaw (Poland); Wallon, Samuel [Laboratoire de Physique Théorique, UMR 8627, CNRS, University Paris Sud,Université Paris-Saclay,91405 Orsay (France); UPMC University Paris 06, Faculté de Physique,4 place Jussieu, 75252 Paris Cedex 05 (France); Xiao, Bo-Wen [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics,Central China Normal University, Wuhan 430079 (China); Yuan, Feng [Nuclear Science Division, Lawrence Berkeley National Laboratory,Berkeley, CA 94720 (United States)

    2016-03-15

    In high energy hadron-hadron collisions, dijet production with large rapidity separation proposed by Mueller and Navelet, is one of the most interesting processes which can help us to directly access the well-known Balitsky-Fadin-Kuraev-Lipatov evolution dynamics. The objective of this work is to study the Sudakov resummation of Mueller-Navelet jets. Through the one-loop calculation, Sudakov type logarithms are obtained for this process when the produced dijets are almost back-to-back. These results could play an important role in the phenomenological study of dijet correlations with large rapidity separation at the LHC.

  19. EtfA catalyses the formation of dipicolinic acid in Clostridium perfringens.

    Science.gov (United States)

    Orsburn, Benjamin C; Melville, Stephen B; Popham, David L

    2010-01-01

    Dipicolinic acid (DPA) is a major component of bacterial endospores, comprising 5-15% of the spore dry weight, and is important for spore stability and resistance properties. The biosynthetic precursor to DPA, dihydro-dipicolinic acid (DHDPA), is produced by DHDPA synthase within the lysine biosynthesis pathway. In Bacillus subtilis, and most other bacilli and clostridia, DHDPA is oxidized to DPA by the products of the spoVF operon. Analysis of the genomes of the clostridia in Cluster I, including the pathogens Clostridium perfringens, Clostridium botulinum and Clostridium tetani, has shown that no spoVF orthologues exist in these organisms. DPA synthase was purified from extracts of sporulating C. perfringens cells. Peptide sequencing identified an electron transfer flavoprotein, EtfA, in this purified protein fraction. A C. perfringens strain with etfA inactivated is blocked in late stage sporulation and produces < or = 11% of wild-type DPA levels. C. perfringens EtfA was expressed in and purified from Escherichia coli, and this protein catalysed DPA formation in vitro. The sequential production of DHDPA and DPA in C. perfringens appears to be catalysed by DHDPA synthase followed by EtfA. Genome sequence data and the taxonomy of spore-forming species suggest that this may be the ancestral mechanism for DPA synthesis.

  20. Mueller matrix polarimetry for the characterization of complex ...

    Indian Academy of Sciences (India)

    3.2 Monitoring stem cell-based regenerative treatments of the heart. Mueller matrix decomposition method was explored for polarimetric monitoring of the regeneration of myocardial tissues following stem-cell therapy. The anisotropic organized nature of myocardial tissues originating from their fibrous structure leads.

  1. 60 years Geiger-Mueller counter - 40 years scintillation counter

    International Nuclear Information System (INIS)

    Stolz, W.; Herforth, L.

    1988-01-01

    This review is devoted to two anniversaries that of the invention of the Geiger-Mueller counter sixty years ago and that of the development of the scintillation counter forty years ago. Besides the history described the importance at the present time is emphasized. The advances made in further improvement of these detectors are considered. 99 refs. (author)

  2. Ferdinand von Mueller's interactions with Charles Darwin and his response to Darwinism.

    Science.gov (United States)

    Lucas, A M

    2010-01-01

    Although Ferdinand Mueller (later von Mueller), Government Botanist of Victoria, opposed Darwin's theories when "On the origin of species" was published, there has been little detailed study of the nature of Mueller's opposition from 1860, when he received a presentation copy of "Origin," to his death in 1896. Analysis of Mueller's correspondence and publications shows that he remained a theist and misunderstood key aspects of Darwin's theory. However, Mueller did come to accept that natural selection could operate within a species, although never accepting it could produce speciation. Despite these differences he retained a cordial relationship with Darwin.

  3. Bacterial growth on Mueller Hinton medium sterilized by. gamma. -radiation

    Energy Technology Data Exchange (ETDEWEB)

    Eisenberg, E. (Israel Atomic Energy Commission, Yavne. Soreq Nuclear Research Center); Bogokowsky, B.; Altmann, G. (Sheba Medical Center, Tel Hashomer (Israel); Tel Aviv Univ. (Israel). Medical School)

    1981-12-01

    The possibility of radiosterilization of culture media for the cultivation of bacteria was investigated. Mueller Hinton agar, a medium widely used for the propagation of some fastidious pathogenic bacteria, was sterilized with 1.0 and 1.5 Mrad doses of ..gamma..-radiation. Bacteria belonging to seven different species grew as well on the radiosterilized medium as on medium sterilized by heat in a conventional way. Reduction in colony size was observed on the radiosterilized medium with Staphylococcus aureus and Shigella boydii. Neisseria meningitidis, the most fastidious bacterium tested, did not grow at all. The addition of small amounts of catalase corrected the deleterious radiation effect and all bacteria tested could be successfully grown on irradiated Mueller Hinton agar supplemented with up to 11 Keil units catalase per liter medium.

  4. Stokes-vector and Mueller-matrix polarimetry [Invited].

    Science.gov (United States)

    Azzam, R M A

    2016-07-01

    This paper reviews the current status of instruments for measuring the full 4×1 Stokes vector S, which describes the state of polarization (SOP) of totally or partially polarized light, and the 4×4 Mueller matrix M, which determines how the SOP is transformed as light interacts with a material sample or an optical element or system. The principle of operation of each instrument is briefly explained by using the Stokes-Mueller calculus. The development of fast, automated, imaging, and spectroscopic instruments over the last 50 years has greatly expanded the range of applications of optical polarimetry and ellipsometry in almost every branch of science and technology. Current challenges and future directions of this important branch of optics are also discussed.

  5. PHYSIOLOGY OF ACID BASE BALANCE

    Directory of Open Access Journals (Sweden)

    Awati

    2014-12-01

    Full Text Available Acid-base, electrolyte, and metabolic disturbances are common in the intensive care unit. Almost all critically ill patients often suffer from compound acid-base and electrolyte disorders. Successful evaluation and management of such patients requires recognition of common patterns (e.g., metabolic acidosis and the ability to dissect one disorder from another. The intensivists needs to identify and correct these condition with the easiest available tools as they are the associated with multiorgan failure. Understanding the elements of normal physiology in these areas is very important so as to diagnose the pathological condition and take adequate measures as early as possible. Arterial blood gas analysis is one such tool for early detection of acid base disorder. Physiology of acid base is complex and here is the attempt to simplify it in our day to day application for the benefit of critically ill patients.

  6. Mueller Matrix: the Consummate approach to imaging in torbid media

    Science.gov (United States)

    Zhai, Peng-Wang; Kattawar, George W.

    2004-10-01

    The use of polarized light has important applications in astronomy, atmospheric science, chemistry, biology, interferometry, medical science, quantum theory, and the commercial sector. The four component Stokes vector is one of the most popular ways to describe polarized states of light and the 4×4 Mueller matrix is used to express the relations between the Stokes vectors of the incident light and the scattered light. Of the many methods to calculate the single scattering Mueller matrix, we will emphasize the Mie theory; the T-matrix method; the finite-element method (FEM); the finite-difference time-domain method (FDTD); the discrete dipole approximation (DDA). The single scattering Mueller matrices for particles can be used to solve the radiative transfer equations for multiple scattering systems, which is the sine que non for the remote sensing applications. Of the many ways to solve the radiative transfer equations we will discuss the discrete-ordinate method, the adding and doubling method, and the Monte-Carlo method, which is by far the most versatile.

  7. A Mueller bridge set for cryogenic temperature measurements

    DEFF Research Database (Denmark)

    Diamond, J.M.

    1966-01-01

    An a.c. Mueller bridge set for resistance thermometry at cryogenic temperature is described. A commercial tuned null detector is used at an operating frequency of 1025 c/s. The set includes a high stability oscillator, line reject filter, phase shifter, Q multiplier and selector box. The latter...... permits the dissipation in the thermometers not being measured to be maintained at the operating level with direct current. A temperature change of the order of 10 μdegK can be detected with 10-8 W applied to the thermometer....

  8. Mueller matrix spectroscopic ellipsometry study of chiral nanocrystalline cellulose films

    Science.gov (United States)

    Mendoza-Galván, Arturo; Muñoz-Pineda, Eloy; Ribeiro, Sidney J. L.; Santos, Moliria V.; Järrendahl, Kenneth; Arwin, Hans

    2018-02-01

    Chiral nanocrystalline cellulose (NCC) free-standing films were prepared through slow evaporation of aqueous suspensions of cellulose nanocrystals in a nematic chiral liquid crystal phase. Mueller matrix (MM) spectroscopic ellipsometry is used to study the polarization and depolarization properties of the chiral films. In the reflection mode, the MM is similar to the matrices reported for the cuticle of some beetles reflecting near circular left-handed polarized light in the visible range. The polarization properties of light transmitted at normal incidence for different polarization states of incident light are discussed. By using a differential decomposition of the MM, the structural circular birefringence and dichroism of a NCC chiral film are evaluated.

  9. Enhanced dipicolinic acid production during the stationary phase in Bacillus subtilis by blocking acetoin synthesis.

    Science.gov (United States)

    Toya, Yoshihiro; Hirasawa, Takashi; Ishikawa, Shu; Chumsakul, Onuma; Morimoto, Takuya; Liu, Shenghao; Masuda, Kenta; Kageyama, Yasushi; Ozaki, Katsuya; Ogasawara, Naotake; Shimizu, Hiroshi

    2015-01-01

    Bacterial bio-production during the stationary phase is expected to lead to a high target yield because the cells do not consume the substrate for growth. Bacillus subtilis is widely used for bio-production, but little is known about the metabolism during the stationary phase. In this study, we focused on the dipicolinic acid (DPA) production by B. subtilis and investigated the metabolism. We found that DPA production competes with acetoin synthesis and that acetoin synthesis genes (alsSD) deletion increases DPA productivity by 1.4-fold. The mutant showed interesting features where the glucose uptake was inhibited, whereas the cell density increased by approximately 50%, resulting in similar volumetric glucose consumption to that of the parental strain. The metabolic profiles revealed accumulation of pyruvate, acetyl-CoA, and the TCA cycle intermediates in the alsSD mutant. Our results indicate that alsSD-deleted B. subtilis has potential as an effective host for stationary-phase production of compounds synthesized from these intermediates.

  10. Ultrafast responses of dipolar and octupolar compounds with dipicolinate as an electron acceptor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yaochuan, E-mail: ycwang@dlmu.edu.cn [Department of Physics, Dalian Maritime University, Dalian 116026 (China); State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China); Liu, Siyuan; Liu, Dajun; Wang, Guiqiu [Department of Physics, Dalian Maritime University, Dalian 116026 (China); Xiao, Haibo [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China)

    2016-11-01

    Two dipolar compounds with dipicolinate as electron acceptor group named trans-dimethyl-4-[4’-(N,N-dimethylamino)-styry1]-pyridin-2,6-dicarboxylate (M-1), trans-dimethyl-4-[4'-(N,N-diphenylamino)-styry1]-pyridin-2,6-dicarboxylate (P-1) as well as a P-1 based multi-branched octupolar compound {4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl) vinyl]}-N,N-bis{4-[(E)-2-(2,6-dimethoxycarbonylpyridin-4-yl)vinylphenyl]} aniline (P-3) with intense two-photon fluorescence emission properties are systematically investigated by using steady-state absorption and fluorescence spectroscopy, Z-scan, and two-photon excited fluorescence (TPF) method. The two-photon absorption cross section of octupolar compound P-3 in THF solution is determined to be 376 GM, which is approximately 12 times greater than that of dipolar counterpart P-1 (32 GM). Transient absorption spectroscopy is employed to investigate the excited state dynamics of the dipolar and octupolar compounds. The formation and relaxation lifetimes of the intra-molecular charge transfer (ICT) state are determined to be in the ranges of several picoseconds and several-hundreds of picoseconds, respectively, for all the three compounds in THF solutions. An extended π-conjugated system and increased intra-molecular cooperative effect are responsible for the observed large two-photon absorption character. - Highlights: • Octupolar compound gain 12-fold enhancement of two photon absorption. • Dynamic properties of intra-molecular charge transfer state are determined. • Cooperative effect is responsible for great increase of two photon character.

  11. Mueller matrix mapping of biological polycrystalline layers using reference wave

    Science.gov (United States)

    Dubolazov, A.; Ushenko, O. G.; Ushenko, Yu. O.; Pidkamin, L. Y.; Sidor, M. I.; Grytsyuk, M.; Prysyazhnyuk, P. V.

    2018-01-01

    The paper consists of two parts. The first part is devoted to the short theoretical basics of the method of differential Mueller-matrix description of properties of partially depolarizing layers. It was provided the experimentally measured maps of differential matrix of the 1st order of polycrystalline structure of the histological section of brain tissue. It was defined the statistical moments of the 1st-4th orders, which characterize the distribution of matrix elements. In the second part of the paper it was provided the data of statistic analysis of birefringence and dichroism of the histological sections of mice liver tissue (normal and with diabetes). It were defined the objective criteria of differential diagnostics of diabetes.

  12. New complexes of Cu(II) with dipicolinate and pyridyl-based ligands: An experimental and DFT approach.

    Science.gov (United States)

    Luzardo, Florencia; Álvarez, Natalia; Kremer, Carlos; de Camargo, Andrea S S; Gancheff, Jorge S

    2017-08-05

    The three novel mononuclear copper(II) complexes with dipicolinate and pyridyl-based ligands [Cu(dipic)(L)(OH 2 )] (L=4-picoline, vinylpyridine, 4-styrylpyridine; dipic 2- =dipicolinate) were afforded and structurally characterized. X-ray diffraction studies accounted for slight distorted square-pyramidal structures in which the dianion dipic 2- acts as a tridentate ligand in a mer-fashion, the N-donor species occupy an in-plane position, and a water molecule was detected apically coordinated. To assess the effect of the nature of the pyridyl-substituent (para position) on electronic properties, other complexes were also synthesized: [Cu(dipic)(py)(OH 2 )], [{Cu(dipic)(OH 2 )} 2 (μ-pyz)] and [{Cu(dipic)(OH 2 )}(μ-pypy){Cu(dipic)}] (py=pyridine, pyz=pyrazine, pypy=(E)-1,2-bis(pyridine-4-yl)ethane). Absorptive behavior in the UV-VIS region was studied in solution and in the solid state (reflectance measurements). Additionally, geometry and population analyses were conducted by means of DFT calculations. Electronic UV-VIS spectra were simulated for both dinuclear complexes in the framework of the TD-DFT methodology to assign the origin of the absorption bands. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Biosynthesis of silver nanoparticles by Bacillus stratosphericus spores and the role of dipicolinic acid in this process.

    Science.gov (United States)

    Hosseini-Abari, Afrouzossadat; Emtiazi, Giti; Lee, Sang-Hyuk; Kim, Byung-Gee; Kim, June-Hyung

    2014-09-01

    Seeking for simple, rapid, and environmental-friendly routes to produce metal nanoparticles is quite attractive for various biotechnological applications. Biological synthesis method of silver nanoparticles has been found very promising due to their non-toxicity and simplicity. Here, the spores of Bacillus stratosphericus isolated from soil enriched with 30 % H2O2 were used for the production of silver nanoparticles. Furthermore, the possible mechanism of silver nanoparticle synthesis by the spores was elucidated for the first time. In this regard, dipicolinic acid (DPA) was shown to play a critical role as a nanoparticle-producing agent. UV-Vis absorption spectroscopy, X-ray diffraction technique, energy-dispersive spectroscopy, and transmission electron microscopy were used to characterize the nanoparticles. Unlike vegetative cells of B. stratosphericus, the spores and the purified DPA were capable of producing nanoparticles from silver nitrate (AgNO3). These biogenic nanoparticles, which were highly toxic against different pathogenic bacteria, showed mixed structures including spherical, triangular, cubic, and hexagonal with the approximate size between 2 and 20 nm in diameter. Our results illustrated the role of dipicolinic acid as a main factor for the synthesis of nanoparticles by the bacterial spores.

  14. Demonstration of full 4×4 Mueller polarimetry through an optical fiber for endoscopic applications.

    Science.gov (United States)

    Manhas, Sandeep; Vizet, Jérémy; Deby, Stanislas; Vanel, Jean-Charles; Boito, Paola; Verdier, Mireille; De Martino, Antonello; Pagnoux, Dominique

    2015-02-09

    A novel technique to measure the full 4 × 4 Mueller matrix of a sample through an optical fiber is proposed, opening the way for endoscopic applications of Mueller polarimetry for biomedical diagnosis. The technique is based on two subsequent Mueller matrices measurements: one for characterizing the fiber only, and another for the assembly of fiber and sample. From this differential measurement, we proved theoretically that the polarimetric properties of the sample can be deduced. The proof of principle was experimentally validated by measuring various polarimetric parameters of known optical components. Images of manufactured and biological samples acquired by using this approach are also presented.

  15. Doing the Impossible George E Mueller and the Management of NASA’s Human Spaceflight Program

    CERN Document Server

    Slotkin, Arthur L

    2012-01-01

    This excellent account of one of the most important personalities in early American human spaceflight history describes for the first time how George E. Mueller, the system manager of the human spaceflight program of the 1960s, applied the SPO methodology and other special considerations, resulting in the success of the Apollo Program. While Wernher von Braun and others did not really readily accept Mueller's approach to system management, they later acknowledged that without it NASA would not have landed astronauts on the Moon by 1969. While Apollo remained Mueller's top priority, from his earliest days at the agency he promoted a robust post-Apollo program, which culminated in Skylab, the Space Shuttle, and the International Space Station. As a result of these efforts, Mueller earned the sobriquet: "the father of the Space Shuttle."

  16. General formalism for partial spatial coherence in reflection Mueller matrix polarimetry.

    Science.gov (United States)

    Ossikovski, Razvigor; Hingerl, Kurt

    2016-09-01

    Starting from the first principles, we derive the expressions governing partially coherent Mueller matrix reflection polarimetry on spatially inhomogeneous samples. These are reported both in their general form and in the practically important specific form for two juxtaposed media.

  17. Mueller matrix polarimetry for characterizing microstructural variation of nude mouse skin during tissue optical clearing.

    Science.gov (United States)

    Chen, Dongsheng; Zeng, Nan; Xie, Qiaolin; He, Honghui; Tuchin, Valery V; Ma, Hui

    2017-08-01

    We investigate the polarization features corresponding to changes in the microstructure of nude mouse skin during immersion in a glycerol solution. By comparing the Mueller matrix imaging experiments and Monte Carlo simulations, we examine in detail how the Mueller matrix elements vary with the immersion time. The results indicate that the polarization features represented by Mueller matrix elements m22&m33&m44 and the absolute values of m34&m43 are sensitive to the immersion time. To gain a deeper insight on how the microstructures of the skin vary during the tissue optical clearing (TOC), we set up a sphere-cylinder birefringence model (SCBM) of the skin and carry on simulations corresponding to different TOC mechanisms. The good agreement between the experimental and simulated results confirm that Mueller matrix imaging combined with Monte Carlo simulation is potentially a powerful tool for revealing microscopic features of biological tissues.

  18. First complete NLL BFKL calculation of Mueller Navelet jets at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Wallon, Samuel [Laboratoire de Physique Theorique d' Orsay - LPT, Bat. 210, Univ. Paris-Sud 11, 91405 Orsay Cedex (France); UPMC Univ. Paris 06 (France); Colferai, Dimitri [Dipartimento di Fisica, Universita di Firenze, Via G. Sansone 1, IT-50019 Firenze (Italy); Istituto Nazionale di Fisica Nucleare - INFN, Sezione di Firenze, Via G.Sansone 1, I-50019 Sesto Fiorentino, Firenze (Italy); Schwennsen, Florian [Deutsches Elektronen-Synchrotron - DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Szymanowski, Lech [Soltan Institute for Nuclear Studies, Hoza 69, 00691, Warsaw (Poland)

    2010-07-01

    We calculate cross section and azimuthal de-correlation of Mueller Navelet jets at the LHC in the complete next-lo-leading order BFKL framework, i.e. including next-to-leading corrections to the Green's function as well as next-to-leading corrections to the Mueller Navelet vertices. The obtained results for standard observables proposed for studies of Mueller Navelet jets show that both sources of corrections are of equal, big importance for final magnitude and final behavior of observables. The astonishing conclusion of our analysis is that the observables obtained within the complete next-lo-leading order BFKL framework of the present work are quite similar to the same observables obtained within next-to-leading logarithm DGLAP type treatment. This fact sheds doubts on general belief that the studies of Mueller Navelet jets at the LHC will lead to clear discrimination between the BFKL and the DGLAP dynamics. (author)

  19. Mueller matrix microscopy for label-free histopathology examinations (Conference Presentation)

    Science.gov (United States)

    Lv, Donghong; He, Honghui; Zhou, Jialing; Ma, Hui

    2017-03-01

    In clinical medicine, a pathologist often needs to examine cells or thin slices of tissues to identify abnormalities that are markers or precursors of diseases. Various chemical and immunohistochemical staining techniques have been developed to selectively label certain components to bring up the contrasts of specific microstructures. It is well known that a Mueller matrix contains rich information on the microstructure and optical properties of a sample. Using proper data analysis techniques, Mueller matrix images can also be transformed into new polarization parameters sensitive only to specific microstructural features. These new polarization parameters can selectively enhance the contrast of specific features in images of unstained pathological slide to help identify abnormalities. In recent studies, we set up a modulus design Mueller matrix microscope by adding polarization optics components into the optical path of a commercial transmission microscope. We take multiple measurements of the unstained pathological slide at different polar and azimuth angles, then derive an intrinsic Mueller matrix (IMM) which represents only the microstructural characters of the sample without the interference by the sample orientation. Such orientation-independent IMM images preserve to the maximum extent the pathological information of the tissue samples. Using Mueller matrix decomposition and transformation techniques, we demonstrate in preliminary tests that we are able to selectively enhance different characteristic features in different cancer tissues. With the fast advances in big-data analysis techniques, it is expected that label-free Mueller matrix microscopy is a potentially powerful tool for the histopathologists to identify characteristic features in complex tissue samples.

  20. Classification of morphologically similar algae and cyanobacteria using Mueller matrix imaging and convolutional neural networks.

    Science.gov (United States)

    Li, Xianpeng; Liao, Ran; Zhou, Jialing; Leung, Priscilla T Y; Yan, Meng; Ma, Hui

    2017-08-10

    We present the Mueller matrix imaging system to classify morphologically similar algae based on convolutional neural networks (CNNs). The algae and cyanobacteria data set contains 10,463 Mueller matrices from eight species of algae and one species of cyanobacteria, belonging to four phyla, the shapes of which are mostly randomly oriented spheres, ovals, wheels, or rods. The CNN serves as an automatic machine with learning ability to help in extracting features from the Mueller matrix, and trains a classifier to achieve a 97% classification accuracy. We compare the performance in two ways. One way is to compare the performance of five CNNs that differ in the number of convolution layers as well as the classical principle component analysis (PCA) plus the support vector machine (SVM) method; the other way is to quantify the differences of scores between full Mueller matrix and the first matrix element m11, which does not contain polarization information under the same conditions. As the results show, deeper CNNs perform better, the best of which outperforms the conventional PCA plus SVM method by 19.66% in accuracy, and using the full Mueller matrix earns 6.56% increase of accuracy than using m11. It demonstrates that the coupling of Mueller matrix imaging and CNN may be a promising and efficient solution for the automatic classification of morphologically similar algae.

  1. Differentiating characteristic microstructural features of cancerous tissues using Mueller matrix microscope.

    Science.gov (United States)

    Wang, Ye; He, Honghui; Chang, Jintao; Zeng, Nan; Liu, Shaoxiong; Li, Migao; Ma, Hui

    2015-12-01

    Polarized light imaging can provide rich microstructural information of samples, and has been applied to the detections of various abnormal tissues. In this paper, we report a polarized light microscope based on Mueller matrix imaging by adding the polarization state generator and analyzer (PSG and PSA) to a commercial transmission optical microscope. The maximum errors for the absolute values of Mueller matrix elements are reduced to 0.01 after calibration. This Mueller matrix microscope has been used to examine human cervical and liver cancerous tissues with fibrosis. Images of the transformed Mueller matrix parameters provide quantitative assessment on the characteristic features of the pathological tissues. Contrast mechanism of the experimental results are backed up by Monte Carlo simulations based on the sphere-cylinder birefringence model, which reveal the relationship between the pathological features in the cancerous tissues at the cellular level and the polarization parameters. Both the experimental and simulated data indicate that the microscopic transformed Mueller matrix parameters can distinguish the breaking down of birefringent normal tissues for cervical cancer, or the formation of birefringent surrounding structures accompanying the inflammatory reaction for liver cancer. With its simple structure, fast measurement and high precision, polarized light microscope based on Mueller matrix shows a good diagnosis application prospect. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Development of tecniques for constructing Geiger-Mueller counters

    International Nuclear Information System (INIS)

    Baccarelli, A.M.

    1984-01-01

    A systematic study of several construction techniques of Geiger-Mueller counters was carried out in order to establish the most suitable technology for such purpose. The results obtained with counters for alpha, beta and gamma rays, which were designed and built in the laboratory of Sao Paulo University (USP) are described. Most of the counters were built inside Pyrex-glass envelope and their cathodes were made of electrolytic copper or brass foils of still a silver layer deposited by chemical process. Some counters were made with cilyndrical brass tube. Anode wires of different materials and diameters and severals quenching vapors were used and the results obtained are described. All the procedures used in preparation of surfaces, cleaning of materials, purification of filling mixtures, the procedures for operating evacuation and filling of counters are described. The results obtained with self quenching counters using soda glass and an external colloidas graphite cathode are presented and the influence of filling mixtures is analysed. A technology to produce reliable counters from materials and gases easily available in the country was established. It is shown that counters with an external cathode can be used when recovery time on order of 2 μs are required. The plateus obtained for such counters were on order of 1000V with slope of about 0.5%. (Author) [pt

  3. Calibration of Farmer dosimeter and Geiger-Mueller counters

    International Nuclear Information System (INIS)

    Yudelev, M.; Jones, D.T.L.

    1988-11-01

    According to the protocol adopted at NAC for neutron beam calibration a Farmer type dosimeter is the Secondary Standard instrument used to obtain the exposure calibration factors for tissue equivalent (TE) ion chambers in Co-60 beam. Miniature Geiger-Mueller (GM) counters are used in conjunction with the TE ion chambers to determine the gamma dose component in mixed neutron-gamma radiation fields which are produced by the neutron therapy treatment system. The calibration factors for the GM counters are somewhat lower (∼10%) than previous measurements with similar counters. The orientational changes in the sensitivity of the GM counters cause a change of about 14% in the calibration factor of Far West Technology (GM2) counter and about 2% for Alrad (ZP1300) counters either with or without the Li 6 F caps. The attenuation of the Co-60 gamma rays in the Li 6 F cap results in an increase of the calibration factor by about 2% for all counters. 2 figs., 5 refs., 4 tabs

  4. Increased dipicolinic acid production with an enhanced spoVF operon in Bacillus subtilis and medium optimization.

    Science.gov (United States)

    Takahashi, Fumikazu; Sumitomo, Nobuyuki; Hagihara, Hiroshi; Ozaki, Katsuya

    2015-01-01

    Dipicolinic acid (DPA) is a multi-functional agent for cosmetics, antimicrobial products, detergents, and functional polymers. The aim of this study was to design a new method for producing DPA from renewable material. The Bacillus subtilis spoVF operon encodes enzymes for DPA synthase and the part of lysine biosynthetic pathway. However, DPA is only synthesized in the sporulation phase, so the productivity of DPA is low level. Here, we report that DPA synthase was expressed in vegetative cells, and DPA was produced in the culture medium by replacement of the spoVFA promoter with other highly expressed promoter in B. subtilis vegetative cells, such as spoVG promoter. DPA levels were increased in the culture medium of genetically modified strains. DPA productivity was significantly improved up to 29.14 g/L in 72 h culture by improving the medium composition using a two-step optimization technique with the Taguchi methodology.

  5. Selective optical scattering characterisation of tissue malignancy using Mueller matrix polarimetry: a simulation study

    Science.gov (United States)

    Fathima, Adeeba; Sujatha, N.

    2016-04-01

    Quantitative Mueller polarimetry optically characterizes a medium and is reflected upon by the ultrastructural changes in it. Tissue morphology changes occur during advent of diseases like cancer neoplasia. This alters the Mueller matrix characterizing the tissue as an optical element. The nucleus size undergoes an approximate doubling during the development of cancer. Cell crowding during cancer increases the number density of the nuclei per unit volume. Modeling the cell nuclei as main scattering centers, a systematic computational study on how Mueller matrix elements vary for an increase in scatterer size and number density is performed. Simulation on polarized light transport of wavelength 633nm through a slab of size 3 mm comprising of spherical scatterers in a medium of refractive index 1.33 is carried out. Light propagation is modeled using Monte Carlo method and meridian plane method is adopted for tracking the polarization state change. The stokes vector of the outgoing light is tracked to calculate the Mueller matrix images of the light backscattered from the slab. The Mueller matrix elements as well as depolarization factors are derived. The depolarization index increases with scatterer size. Along with nucleus size, change in the cell number density is also expected in the different stages of the cancer growth. Volume fraction of the scatterers in medium is varied as an indicator of this number density change. Behavior of Mueller matrix with respect to change in scattering coefficient due to variation in scatterer size and volume fraction is studied. It is observed that the depolarization index derived from Mueller matrix has selective discrimination towards the change in scattering coefficient caused due to size change and volume fraction change respectively.

  6. The Conjugate Acid-Base Chart.

    Science.gov (United States)

    Treptow, Richard S.

    1986-01-01

    Discusses the difficulties that beginning chemistry students have in understanding acid-base chemistry. Describes the use of conjugate acid-base charts in helping students visualize the conjugate relationship. Addresses chart construction, metal ions, buffers and pH titrations, and the organic functional groups and nonaqueous solvents. (TW)

  7. The Kidney and Acid-Base Regulation

    Science.gov (United States)

    Koeppen, Bruce M.

    2009-01-01

    Since the topic of the role of the kidneys in the regulation of acid base balance was last reviewed from a teaching perspective (Koeppen BM. Renal regulation of acid-base balance. Adv Physiol Educ 20: 132-141, 1998), our understanding of the specific membrane transporters involved in H+, HCO , and NH transport, and especially how these…

  8. Reducing the orientation influence of Mueller matrix measurements for anisotropic scattering media

    Science.gov (United States)

    Sun, Minghao; He, Honghui; Zeng, Nan; Du, E.; He, Yonghong; Ma, Hui

    2014-09-01

    Mueller matrix polarimetry techniques contain rich micro-structural information of samples, such as the sizes and refractive indices of scatterers. Recently, Mueller matrix imaging methods have shown great potentials as powerful tools for biomedical diagnosis. However, the orientations of anisotropic fibrous structures in tissues have prominent influence on Mueller matrix measurements, resulting in difficulties for extracting micro-structural information effectively. In this paper, we apply the backscattering Mueller matrix imaging technique to biological samples with different microstructures, such as chicken heart muscle, bovine skeletal muscle, porcine liver and fat tissues. Experimental results show that the directions of the muscle fibers have prominent influence on the Mueller matrix elements. In order to reduce the orientation influence, we adopt the rotation-independent MMT and RLPI parameters, which were proposed in our previous studies, to the tissue samples. Preliminary results in this paper show that the orientation-independent parameters and their statistic features are helpful for analyzing the tissues to obtain their micro-structural properties. Since the micro-structure variations are often related to the pathological changes, the method can be applied to microscope imaging techniques and used to detect abnormal tissues such as cancer and other lesions for diagnosis purposes.

  9. Mueller-matrix modeling and characterization of a dual-crystal electro-optic modulator.

    Science.gov (United States)

    Cervantes-L, Joel; Serrano-Garcia, David I; Otani, Yukitoshi; Cense, Barry

    2016-10-17

    A general mathematical model based on Mueller-matrix calculation is presented to describe the optical behavior of a dual-crystal electro-optic modulator. The two crystals inside the modulator are oriented at ± 45° with respect to the horizontal, thereby cancelling natural birefringence and temperature-induced birefringence. We describe the behavior of the modulator as a function of the ellipticity of the crystals, the rotation angles of the crystals and the applied voltage. By fitting the measured data with a Mueller-matrix model that uses values for the ellipticity and orientation angles of the crystals, the simulated data and the experimental measurements could be matched. This Mueller-matrix includes physical properties of the thermally compensated electro optic modulator, and the matrix can be used in simulations where these device-specific properties are important, for instance in the modeling of a polarization-sensitive optical coherence tomography system.

  10. Quantitative characterization of articular cartilage using Mueller matrix imaging and multiphoton microscopy.

    Science.gov (United States)

    Ellingsen, Pål Gunnar; Lilledahl, Magnus Borstad; Aas, Lars Martin Sandvik; Davies, Catharina de Lange; Kildemo, Morten

    2011-11-01

    The collagen meshwork in articular cartilage of chicken knee is characterized using Mueller matrix imaging and multiphoton microscopy. Direction and degree of dispersion of the collagen fibers in the superficial layer are found using a Fourier transform image-analysis technique of the second-harmonic generated image. Mueller matrix images are used to acquire structural data from the intermediate layer of articular cartilage where the collagen fibers are too small to be resolved by optical microscopy, providing a powerful multimodal measurement technique. Furthermore, we show that Mueller matrix imaging provides more information about the tissue compared to standard polarization microscopy. The combination of these techniques can find use in improved diagnosis of diseases in articular cartilage, improved histopathology, and additional information for accurate biomechanical modeling of cartilage.

  11. Fast near infra-red ferroelectric liquid crystal based Mueller matrix system for imaging and spectroscopy

    Directory of Open Access Journals (Sweden)

    Lindgren M.

    2010-06-01

    Full Text Available The science and optical engineering of imaging Mueller Matrix Ellipsometry (MME and Spectroscopic MME is currently being revitalized based on an efficient optimal design method, and through the use of the so-called Eig envalue Calibration Technique (ECT. Through the ECT one may efficiently measure the details of the polarization state generator (PSG matrix, and the polarization state analyzer (PSA matrix, and hence avoid modeling of any unknown polarizing components in the system, and in particular the exact response of complex polarizing elements such as liquid crystal retarders. We here start up with presenting a detailed an alysis of the dynamic response of a near infrared Ferroelectric Liquid Crystal based Mueller matrix ellipsometer (NIR FLC- MME [1] . A time dependent simulation model, using the measured time response of the individual FLCs, is used to describe the measured temporal response. Furthermore, the impulse response of the detector and the pre-amplifier is characterized and in cluded in the simulation model. The measured time dependent intensity response of the MME is well explained by simulations. A FLC based NIRMME system is here shown to be able to operate accurately at the maximum speed of approximately 16 ms per Mueller matrix measurement (steady state response. We demonstrate here time dependent Mueller Matrix measurements of a dynamically changing sample, with even down to 8 ms sampling time of each complete Mueller Matrix (with some loss of accuracy. We secondly briefly present the NIR-FLC- MME imaging system, and show applications to strain imaging of a crystal subjected to an external pressure. Furthermore, we present near-infra-red Mueller matrix images and corresponding polar decomposition images of thin slices of bio-tissue [2].

  12. Optical biopsy of tissue with Mueller polarimetry: theory and experiments (Conference Presentation)

    Science.gov (United States)

    Novikova, Tatiana; Meglinski, Igor; Garcia-Caurel, Enric; Bykov, Alexander; Rehbinder, Jean; Deby, Stanislas; Vizet, Jérémy; Pierangelo, Angelo; Moreau, François; Validire, Pierre; Benali, Abdelali; Gayet, Brice; Teig, Benjamin; Nazac, André; Ossikovski, Razvigor

    2017-02-01

    The rise of optical biopsy as an alternative to classical biopsy is dictated by ongoing technological progress: any type of measurements has to be fast, precise, non-invasive and implemented in-vivo. The use of polarized light for optical biopsy has a long history. As Mueller-Stokes formalism provides the most complete description of polarized light interaction with any type of sample (even depolarizing one) we explored the capabilities of in-house multi-wavelength Mueller imaging polarimeter for the detection of pre-malignancy and malignancy. Our studies were performed with both scattering phantom tissues (in transmission configuration) and specimens of human colon and uterine cervix (in backscattering configuration). For the interpretation of measurement results we decomposed Mueller matrix of a sample into product of elementary Mueller matrices of homogeneous diattenuator, retarder, and depolarizer. This phenomenological approach does not require the exact solution of Maxwell equations and provides the "effective" values of polarimetric properties of sample. Exploring differential Mueller matrix formalism for fluctuating medium we showed that depolarization in homogeneous turbid medium varied parabolically with the pathlength of transmitted light, while the standard deviation of elementary polarization properties of medium depends linearly on the concentration of scatterers. Neither scattering phantoms nor human tissue possessed any measurable diattenuation in backscattering configuration. The polarimetric images of tissue depolarization power, scalar birefringence and orientation of optical axis were compared with the analysis of histological slides. The spectral dependence of depolarization power and scalar birefringence values ascertained the potential of imaging Mueller polarimetry to discriminate healthy and diseased tissue zones.

  13. Number of independent parameters in the Mueller matrix representation of homogeneous depolarizing media.

    Science.gov (United States)

    Arteaga, Oriol

    2013-04-01

    In general the transmission of polarized light through a homogeneous depolarizing sample has motion-reversal symmetry because the response remains the same for light traveling in the opposite direction. As a consequence, the optical properties of a sample, characterized by the differential Mueller matrix, must be invariant upon motion reversal. This Letter shows that the 16 parameters of the differential Mueller matrix must therefore obey six conditions to satisfy this symmetry. This limits the number of independent parameters to 10. The 10 elementary optical properties of a depolarizing homogeneous medium are defined and discussed.

  14. Solution of the inverse problem of polarimetry for deterministic objects on the base of incomplete Mueller matrices

    International Nuclear Information System (INIS)

    Savenkov, S.M.; Oberemok, Je.A.

    2002-01-01

    Using the Mueller matrix representation in the basis of the matrices of amplitude and phase anisotropies, a generalized solution of the inverse problem of polarimetry for deterministic objects on the base of incomplete Mueller matrices, which have been measured by method of three input polarization, is obtained

  15. Solution of the inverse problem of polarimetry for deterministic objects on the base of incomplete Mueller matrices

    CERN Document Server

    Savenkov, S M

    2002-01-01

    Using the Mueller matrix representation in the basis of the matrices of amplitude and phase anisotropies, a generalized solution of the inverse problem of polarimetry for deterministic objects on the base of incomplete Mueller matrices, which have been measured by method of three input polarization, is obtained.

  16. Fluorescent detection of dipicolinic acid as a biomarker of bacterial spores using lanthanide-chelated gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Donmez, Mert [Department of Chemistry, Faculty of Art and Sciences, Duzce University, Duzce 81620 (Turkey); Yilmaz, M. Deniz, E-mail: deniz.yilmaz@gidatarim.edu.tr [Department of Bioengineering, Faculty of Engineering and Architecture, Konya Food and Agriculture University, Konya 42080 (Turkey); Kilbas, Benan, E-mail: benankilbas@duzce.edu.tr [Department of Chemistry, Faculty of Art and Sciences, Duzce University, Duzce 81620 (Turkey)

    2017-02-15

    Highlights: • The nanosensors based on gold nanoparticles functionalized with lanthanide complexes were synthesized. • The nanosensors selectively and sensitively detected DPA, a biomarker of bacterial spores. • Ratiometric sensing of DPA by a ternary complex was achieved by ligand displacement strategy. - Abstract: Gold nanoparticles (GNPs) functionalized with ethylenediamine-lanthanide complexes (Eu-GNPs and Tb-GNPs) were used for the selective fluorescent detection of dipicolinic acid (DPA), a unique biomarker of bacterial spores, in water. Particles were characterized by transmission electron microscopy and zeta potential measurements. The coordination of DPA to the lanthanides resulted in the enhancement of the fluorescence. A selective response to DPA was observed over the nonselective binding of aromatic ligands. The ligand displacement strategy were also employed for the ratiometric fluorescent detection of DPA. 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedion (TFNB) was chosen as an antenna to synthesize ternary complexes. The addition of DPA on EuGNP:TFNB ternary complex quenched the initial emission of the complex at 615 nm and increased the TFNB emission at 450 nm when excited at 350 nm. The results demonstrated that the ratiometric fluorescent detection of DPA was achieved by ligand displacement strategy.

  17. Improvement in fingerprint detection using Tb(III)-dipicolinic acid complex doped nanobeads and time resolved imaging.

    Science.gov (United States)

    Hauser, Frank M; Knupp, Gerd; Officer, Simon

    2015-08-01

    This paper deals with the synthesis and application of lanthanide complex doped nanobeads used as a luminescent fingerprint powder. Due to their special optical properties, namely a long emission lifetime, sharp emission profiles and large Stokes shifts, luminescent lanthanide complexes are useful for discriminating against signals from background emissions. This is a big advantage because latent fingerprints placed on multicoloured fluorescent surfaces are difficult to develop with conventional powders. The complex of 2,6-dipicolinic acid (DPA) and terbium ([Tb(DPA)3](3-)) is used for this purpose. Using the Stöber process, this complex is incorporated into a silica matrix forming nanosized beads (230-630nm). It is shown that the [Tb(DPA)3](3-) is successfully incorporated into the beads and that these beads exhibit the wanted optical properties of the complex. A phenyl functionalisation is applied to increase the lipophilicity of the beads and finally the beads are used to develop latent fingerprints. A device for time resolved imaging was built to improve the contrast between developed fingerprint and different background signals, whilst still detecting the long lasting luminescence of the complex. The developed fingerprint powder is therefore promising to develop fingerprints on multicoloured fluorescent surfaces. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. Dipicolinate salt of imidazole: Discovering its structure and properties using different experimental methodologies and quantum chemical investigations

    Science.gov (United States)

    Thirumurugan, R.; Anitha, K.

    2018-03-01

    A novel organic proton transfer complex of imidazolium dipicolinate (ID) has been synthesized and it was grown as single crystals using slow evaporation method. The molecular structure of synthesized compound and vibrational modes of its functional groups were confirmed by (1H and 13C) NMR, FTIR and FT-Raman spectroscopic studies, respectively. Single crystal X-ray diffraction (SCXRD) analysis confirmed the orthorhombic system with noncentrosymmetric (NCS), P212121, space group of grown ID crystal. UV-Vis-NIR spectral study confirmed its high optical transparency within the region of 285-1500 nm. Powder second harmonic generation (SHG) efficiency of ID crystal was confirmed and it was 6.8 times that of KDP crystal. TG-DTA and DSC analysis revealed the higher thermal stability of grown crystal as 249 °C. The dielectric response and mechanical behaviour of grown crystal were studied effectively. Density functional theory calculations were performed to probe the relationship between the structure and its properties including molecular optimization, Mulliken atomic charge distribution, frontier molecular orbital (FMOs) and molecular electrostatic potential map (MEP) analysis and first hyperpolarizability. All these experimental and computational results were discussed in this communication and it endorsed the ID compound as a potential NLO candidate could be employed in optoelectronics device applications in near future.

  19. Selective sensitivity of Mueller imaging for tissue scattering over absorption changes in cancer mimicking phantoms

    Science.gov (United States)

    Fathima, Adeeba; Sharma B. S., Mahima; N., Sujatha

    2018-03-01

    Tissue characterization using optical polarimetry, especially Mueller imaging is receiving sustained interest due to its potential in achieving optical contrast between normal and malignant variations. This is particularly important in identifying the margin of malignant growth in suspected tissue regions for accurate surgical removal, or in aiding the sampling procedure during biopsy. The sensitivity of Mueller matrix derived depolarization index to the combined effects of changes in scattering and absorption occurring in a cancerous growth is illustrated in this study. Depolarization imaging is shown to be useful in demarcating the boundary of two regions of differing optical properties using a tissue phantom, modeled according to the changes expected during cancerous growth in tissue. Tissue scattering and absorption are expected to generally increase with the nuclear size change and crowding as well as angiogenesis associated with malignancy. We have observed that there is selective sensitivity for the Mueller elements and derived depolarization index to tissue scattering over absorption in the object field. Although the scattering and absorption are expected to increase and decrease depolarization respectively, the optical contrast of Mueller images and the derived depolarization index between normal and cancerous tissue is found appreciable in this region.

  20. Project and construction of a system to measure with Geiger-Mueller counter

    International Nuclear Information System (INIS)

    Melo, F.A. de.

    1984-01-01

    The project and construction of a Geiger-Mueller detection and analysis system using Brazilian electronic equipment and presented. The measure system has an high voltage source that permits to give variable output voltage in stages of 30 to 30 V, a pulse counter and a clock, that drives simultaneously with the counter. (E.G.) [pt

  1. Hypokalemic paralysis and acid-base balance

    Directory of Open Access Journals (Sweden)

    Ivo Casagranda

    2006-10-01

    Full Text Available Three cases of hypokalemic paralysis are reported, presenting to the Emergency Department. The first is a patient with a hypokalemic periodic paralysis with a normal acid-base status, the second is a case of hypokalemic flaccid paralysis of all extremities with a normal anion gap metabolic acidosis, the last is a patient with a hypokalemic distal paralysis of right upper arm with metabolic alkalosis. Afterwards some pathophysiologic principles and the clinical aspects of hypokalemia are discussed and an appropriate approach to do in Emergency Department, to identify the hypokalemic paralysis etiologies in the Emergency Department, is presented, beginning from the evaluation of acid-base status.

  2. Rapid wide-field Mueller matrix polarimetry imaging based on four photoelastic modulators with no moving parts.

    Science.gov (United States)

    Alali, Sanaz; Gribble, Adam; Vitkin, I Alex

    2016-03-01

    A new polarimetry method is demonstrated to image the entire Mueller matrix of a turbid sample using four photoelastic modulators (PEMs) and a charge coupled device (CCD) camera, with no moving parts. Accurate wide-field imaging is enabled with a field-programmable gate array (FPGA) optical gating technique and an evolutionary algorithm (EA) that optimizes imaging times. This technique accurately and rapidly measured the Mueller matrices of air, polarization elements, and turbid phantoms. The system should prove advantageous for Mueller matrix analysis of turbid samples (e.g., biological tissues) over large fields of view, in less than a second.

  3. Jigsaw Cooperative Learning: Acid-Base Theories

    Science.gov (United States)

    Tarhan, Leman; Sesen, Burcin Acar

    2012-01-01

    This study focused on investigating the effectiveness of jigsaw cooperative learning instruction on first-year undergraduates' understanding of acid-base theories. Undergraduates' opinions about jigsaw cooperative learning instruction were also investigated. The participants of this study were 38 first-year undergraduates in chemistry education…

  4. Quantitatively characterizing the microstructural features of breast ductal carcinoma tissues in different progression stages by Mueller matrix microscope.

    Science.gov (United States)

    Dong, Yang; Qi, Ji; He, Honghui; He, Chao; Liu, Shaoxiong; Wu, Jian; Elson, Daniel S; Ma, Hui

    2017-08-01

    Polarization imaging has been recognized as a potentially powerful technique for probing the microstructural information and optical properties of complex biological specimens. Recently, we have reported a Mueller matrix microscope by adding the polarization state generator and analyzer (PSG and PSA) to a commercial transmission-light microscope, and applied it to differentiate human liver and cervical cancerous tissues with fibrosis. In this paper, we apply the Mueller matrix microscope for quantitative detection of human breast ductal carcinoma samples at different stages. The Mueller matrix polar decomposition and transformation parameters of the breast ductal tissues in different regions and at different stages are calculated and analyzed. For more quantitative comparisons, several widely-used image texture feature parameters are also calculated to characterize the difference in the polarimetric images. The experimental results indicate that the Mueller matrix microscope and the polarization parameters can facilitate the quantitative detection of breast ductal carcinoma tissues at different stages.

  5. Tasked-based quantification of measurement utility for ex vivo multi-spectral Mueller polarimetry of the uterine cervix

    Science.gov (United States)

    Kupinski, Meredith; Rehbinder, Jean; Haddad, Huda; Deby, Stanislas; Vizet, Jérémy; Teig, Benjamin; Nazac, André; Pierangelo, Angelo; Moreau, François; Novikova, Tatiana

    2017-07-01

    Significant contrast in visible wavelength Mueller matrix images for healthy and pre-cancerous regions of excised cervical tissue is shown. A novel classification algorithm is used to compute a test statistic from a small patient population.

  6. Mueller-Navelet jets at LHC: BFKL versus high-energy DGLAP

    Energy Technology Data Exchange (ETDEWEB)

    Celiberto, F.G.; Murdaca, B.; Papa, A. [Dipartimento di Fisica, Universita della Calabria, Cosenza (Italy); Istituto Nazionale di Fisica Nucleare, Gruppo Collegato, Cosenza (Italy); Ivanov, D.Yu. [Sobolev Institute of Mathematics, Novosibirsk (Russian Federation); Novosibirsk State University, Novosibirsk (Russian Federation)

    2015-06-15

    The production of forward jets separated by a large rapidity gap at LHC, the so-called Mueller-Navelet jets, is a fundamental testfield for perturbative QCD in the high-energy limit. Several analyses have already provided us with evidence about the compatibility of theoretical predictions, based on collinear factorization and BFKL resummation of energy logarithms in the next-to-leading approximation, with the CMS experimental data at 7 TeV of center-of-mass energy. However, the question if the same data can be described also by fixed-order perturbative approaches has not yet been fully answered. In this paper we provide numerical evidence that the mere use of partially asymmetric cuts in the transverse momenta of the detected jets allows for a clear separation between BFKL-resummed and fixed-order predictions in some observables related with the Mueller-Navelet jet production process. (orig.)

  7. Bacterial growth on Mueller Hinton medium sterilized by γ-radiation

    International Nuclear Information System (INIS)

    Eisenberg, E.; Bogokowsky, B.; Altmann, G.; Tel Aviv Univ.

    1981-01-01

    The possibility of radiosterilization of culture media for the cultivation of bacteria was investigated. Mueller Hinton agar, a medium widely used for the propagation of some fastidious pathogenic bacteria, was sterilized with 1.0 and 1.5 Mrad doses of γ-radiation. Bacteria belonging to seven different species grew as well on the radiosterilized medium as on medium sterilized by heat in a conventional way. Reduction in colony size was observed on the radiosterilized medium with Staphylococcus aureus and Shigella boydii. Neisseria meningitidis, the most fastidious bacterium tested, did not grow at all. The addition of small amounts of catalase corrected the deleterious radiation effect and all bacteria tested could be successfully grown on irradiated Mueller Hinton agar supplemented with up to 11 Keil units catalase per liter medium. (author)

  8. Ground Operations of the ISS GNC Babb-Mueller Atmospheric Density Model

    Science.gov (United States)

    Brogan, Jonathan

    2002-01-01

    The ISS GNC system was updated recently with a new software release that provides onboard state determination capability. Prior to this release, only the Russian segment maintained and propagated the onboard state, which was periodically updated through Russian ground tracking. The new software gives the US segment the capability for maintaining the onboard state, and includes new GPS and state vector propagation capabilities. Part of this software package is an atmospheric density model based on the Babb-Mueller algorithm. Babb-Mueller efficiently mimics a full analytical density model, such as the Jacchia model. While lacchia is very robust and is used in the Mission Control Center, it is too computationally intensive for use onboard. Thus, Babb-Mueller was chosen as an alternative. The onboard model depends on a set of calibration coefficients that produce a curve fit to the lacchia model. The ISS GNC system only maintains one set of coefficients onboard, so a new set must be uplinked by controllers when the atmospheric conditions change. The onboard density model provides a real-time density value, which is used to calculate the drag experienced by the ISS. This drag value is then incorporated into the onboard propagation of the state vector. The propagation of the state vector, and therefore operation of the BabbMueller algorithm, will be most critical when GPS updates and secondary state vector sources fail. When GPS is active, the onboard state vector will be updated every ten seconds, so the propagation error is irrelevant. When GPS is inactive, the state vector must be updated at least every 24 hours, based on current protocol. Therefore, the Babb-Mueller coefficients must be accurate enough to fulfill the state vector accuracy requirements for at least one day. A ground operations concept was needed in order to manage both the on board Babb-Mueller density model and the onboard state quality. The Babb-Mueller coefficients can be determined operationally

  9. Stroke Volume during Mueller Maneuver Measured by Impedance Cardiography in Patients with Mitral Regurgitation

    Czech Academy of Sciences Publication Activity Database

    Viščor, Ivo; Jurák, Pavel; Vondra, Vlastimil; Halámek, Josef; Leinveber, Pavel

    2009-01-01

    Roč. 36, - (2009), s. 749-751 ISSN 0276-6574 R&D Projects: GA AV ČR IAA200650801; GA ČR GP102/07/P425 Institutional research plan: CEZ:AV0Z20650511 Keywords : Mueller maneuver * impedance cardiography * congestive heart failure Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://cinc.mit.edu/archives/2009/pdf/0749.pdf

  10. Optical diagnosis of dengue virus infected human blood using Mueller matrix polarimetry

    Science.gov (United States)

    Anwar, Shahzad; Firdous, Shamaraz

    2016-08-01

    Currently dengue fever diagnosis methods include capture ELISAs, immunofluorescence tests, and hemagglutination assays. In this study optical diagnosis of dengue virus infection in the whole blood is presented utilizing Mueller matrix polarimetry. Mueller matrices of about 50 dengue viral infected and 25 non-dengue healthy blood samples were recorded utilizing light source from 500 to 700 nm with scanning step of 10 nm. Polar decomposition of the Mueller matrices for all the blood samples was performed that yielded polarization properties including depolarization, diattenuation, degree of polarization, retardance and optical activity, out of which, depolarization index clusters up the diseased and healthy in to different separate groups. The average depolarized light in the case of dengue infection in the whole blood at 500 nm is 18%, whereas for the healthy blood samples it is 13.5%. This suggests that depolarization index of polarized light at the wavelengths of 500, 510, 520, 530 and 540 nm, we find that in case of depolarization index values are higher for dengue viral infection as compared to normal samples. This technique can effectively be used for the characterization of the dengue virus infected at an early stage of disease.

  11. Electric field and temperature in a target induced by a plasma jet imaged using Mueller polarimetry

    Science.gov (United States)

    Slikboer, Elmar; Sobota, Ana; Guaitella, Olivier; Garcia-Caurel, Enric

    2018-01-01

    Mueller polarimetry is used to investigate the behavior of an electro optic target (BSO crystal) under exposure of guided ionization waves produced by an atmospheric pressure plasma jet. For the first time, this optical technique is time resolved to obtain the complete Mueller matrix of the sample right before and after the impact of the discharges. By analyzing the induced birefringence, the spatial profiles and local values are obtained of both the electric field and temperature in the sample. Electric fields are generated due to deposited surface charges and a temperature profile is present, due to the heat transferred by the plasma jet. The study of electric field dynamics and local temperature increase at the target, due to the plasma jet is important for biomedical applications, as well as surface functionalization. This work shows how Mueller polarimetry can be used as a novel diagnostic to simultaneously acquire the spatial distribution and local values of both the electric field and temperature, by coupling the external source of anisotropy to the measured induced birefringence via the symmetry point group of the examined material.

  12. CHARACTERISTIC FEATURES OF MUELLER MATRIX PATTERNS FOR POLARIZATION SCATTERING MODEL OF BIOLOGICAL TISSUES

    Directory of Open Access Journals (Sweden)

    E DU

    2014-01-01

    Full Text Available We developed a model to describe polarized photon scattering in biological tissues. In this model, tissues are simplified to a mixture of scatterers and surrounding medium. There are two types of scatterers in the model: solid spheres and infinitely long solid cylinders. Variables related to the scatterers include: the densities and sizes of the spheres and cylinders, the orientation and angular distribution of cylinders. Variables related to the surrounding medium include: the refractive index, absorption coefficient and birefringence. In this paper, as a development we introduce an optical activity effect to the model. By comparing experiments and Monte Carlo simulations, we analyze the backscattering Mueller matrix patterns of several tissue-like media, and summarize the different effects coming from anisotropic scattering and optical properties. In addition, we propose a possible method to extract the optical activity values for tissues. Both the experimental and simulated results show that, by analyzing the Mueller matrix patterns, the microstructure and optical properties of the medium can be obtained. The characteristic features of Mueller matrix patterns are potentially powerful tools for studying the contrast mechanisms of polarization imaging for medical diagnosis.

  13. Visualizing phase transition behavior of dilute stimuli responsive polymer solutions via Mueller matrix polarimetry.

    Science.gov (United States)

    Narayanan, Amal; Chandel, Shubham; Ghosh, Nirmalya; De, Priyadarsi

    2015-09-15

    Probing volume phase transition behavior of superdiluted polymer solutions both micro- and macroscopically still persists as an outstanding challenge. In this regard, we have explored 4 × 4 spectral Mueller matrix measurement and its inverse analysis for excavating the microarchitectural facts about stimuli responsiveness of "smart" polymers. Phase separation behavior of thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and pH responsive poly(N,N-(dimethylamino)ethyl methacrylate) (PDMAEMA) and their copolymers were analyzed in terms of Mueller matrix derived polarization parameters, namely, depolarization (Δ), diattenuation (d), and linear retardance (δ). The Δ, d, and δ parameters provided useful information on both macro- and microstructural alterations during the phase separation. Additionally, the two step action ((i) breakage of polymer-water hydrogen bonding and (ii) polymer-polymer aggregation) at the molecular microenvironment during the cloud point generation was successfully probed via these parameters. It is demonstrated that, in comparison to the present techniques available for assessing the hydrophobic-hydrophilic switch over of simple stimuli-responsive polymers, Mueller matrix polarimetry offers an important advantage requiring a few hundred times dilute polymer solution (0.01 mg/mL, 1.1-1.4 μM) at a low-volume format.

  14. Imaging linear and circular polarization features in leaves with complete Mueller matrix polarimetry.

    Science.gov (United States)

    Patty, C H Lucas; Luo, David A; Snik, Frans; Ariese, Freek; Buma, Wybren Jan; Ten Kate, Inge Loes; van Spanning, Rob J M; Sparks, William B; Germer, Thomas A; Garab, Győző; Kudenov, Michael W

    2018-03-09

    Spectropolarimetry of intact plant leaves allows to probe the molecular architecture of vegetation photosynthesis in a non-invasive and non-destructive way and, as such, can offer a wealth of physiological information. In addition to the molecular signals due to the photosynthetic machinery, the cell structure and its arrangement within a leaf can create and modify polarization signals. Using Mueller matrix polarimetry with rotating retarder modulation, we have visualized spatial variations in polarization in transmission around the chlorophyll a absorbance band from 650 nm to 710 nm. We show linear and circular polarization measurements of maple leaves and cultivated maize leaves and discuss the corresponding Mueller matrices and the Mueller matrix decompositions, which show distinct features in diattenuation, polarizance, retardance and depolarization. Importantly, while normal leaf tissue shows a typical split signal with both a negative and a positive peak in the induced fractional circular polarization and circular dichroism, the signals close to the veins only display a negative band. The results are similar to the negative band as reported earlier for single macrodomains. We discuss the possible role of the chloroplast orientation around the veins as a cause of this phenomenon. Systematic artefacts are ruled out as three independent measurements by different instruments gave similar results. These results provide better insight into circular polarization measurements on whole leaves and options for vegetation remote sensing using circular polarization. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

  15. Mapping local anisotropy axis for scattering media using backscattering Mueller matrix imaging

    Science.gov (United States)

    He, Honghui; Sun, Minghao; Zeng, Nan; Du, E.; Guo, Yihong; He, Yonghong; Ma, Hui

    2014-03-01

    Mueller matrix imaging techniques can be used to detect the micro-structure variations of superficial biological tissues, including the sizes and shapes of cells, the structures in cells, and the densities of the organelles. Many tissues contain anisotropic fibrous micro-structures, such as collagen fibers, elastin fibers, and muscle fibers. Changes of these fibrous structures are potentially good indicators for some pathological variations. In this paper, we propose a quantitative analysis technique based on Mueller matrix for mapping local anisotropy axis of scattering media. By conducting both experiments on silk sample and Monte Carlo simulation based on the sphere-cylinder scattering model (SCSM), we extract anisotropy axis parameters from different backscattering Mueller matrix elements. Moreover, we testify the possible applications of these parameters for biological tissues. The preliminary experimental results of human cancerous samples show that, these parameters are capable to map the local axis of fibers. Since many pathological changes including early stage cancers affect the well aligned structures for tissues, the experimental results indicate that these parameters can be used as potential tools in clinical applications for biomedical diagnosis purposes.

  16. Criticality Detection Using a Mirion Technologies DRM-2NC Remote Area Monitor Geiger-Mueller Probe

    Science.gov (United States)

    Kryskow, Adam P.

    The prompt fission neutron activation and subsequent response of a DRM-2NC Geiger-Mueller probe (manufactured by Mirion Technologies) was investigated for the purpose of creating a criticality accident detection algorithm with sensitivity and false positive suppression comparable to modern criticality accident detection systems. The expected decay pattern of secondary emissions arising from the neutron induced activity of the Geiger-Mueller probe was investigated experimentally in high neutron fluence environments at research reactors operated by the University of Massachusetts Lowell, Pennsylvania State University, and the White Sands Missile Range of Los Alamos National Laboratory. Monte Carlo techniques were used to both identify key probe materials responsible for the majority of the Geiger-Mueller response and investigate the effects of boron doping to increase detector sensitivity and enhance the signal to noise ratio. Subsequently, a statistical algorithm centered on a point weighted linear regression of the combined effective half-life was developed as the basis for criticality declaration. Final testing of the system indicated that the system was capable of meeting all ANSI criticality accident criteria with sufficient sensitivity to the minimum accident of concern, an adequate response time, and an extremely low likelihood of false alarm.

  17. Acid-base properties of ceramic powders

    International Nuclear Information System (INIS)

    Bleier, A.

    1983-01-01

    This chapter addresses the fundamental aspects of potentiometric titration, electrokinetics, and conductometric titration in evaluating surface and interfacial thermodynamic behavior. Emphasizes the characterization of aqueous systems which are pertinent to the processing of ceramic powders. Attempts to clarify the role of novel analytical techniques that will increasingly contribute to the advanced characterization of ceramic powders. Evaluates recently developed acid-base and complexation concepts and their applications to the processing of oxide ceramics

  18. DISORDERS OF ACID-BASE STATE

    OpenAIRE

    P. F. Litvitskiy

    2011-01-01

    The lecture describes modern data on disorders of acid-base state (ABS): their types, etiology, key stages of pathogenesis, main symptoms, and principles of treatment. The first part of the lecture in present journal characterizes main conception, parameters of ABS in normal state, buffer systems, common mechanisms of BS shifts elimination, etiology and pathogenesis of gas-induced (respiratory) disorders of ABS. The second part of the lecture in following journal will describe not gas-induced...

  19. Synthesis, crystal structure, and spectroscopic characterization of two new binuclear complexes of manganese(II) and vanadium(V) with dipicolinate ligands containing 2-aminopyrimidinium as a counter cation

    Czech Academy of Sciences Publication Activity Database

    Tabatabaee, M.; Mahmoodikhah, H.; Ahadiat, G.; Dušek, Michal; Pojarová, Michaela

    2013-01-01

    Roč. 144, č. 5 (2013), s. 621-626 ISSN 0026-9247 R&D Projects: GA ČR(CZ) GAP204/11/0809 Institutional support: RVO:68378271 Keywords : manganese complex * vanadium complex * dipicolinic ligand * crystal structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.347, year: 2013

  20. Mathematical modeling of acid-base physiology.

    Science.gov (United States)

    Occhipinti, Rossana; Boron, Walter F

    2015-01-01

    pH is one of the most important parameters in life, influencing virtually every biological process at the cellular, tissue, and whole-body level. Thus, for cells, it is critical to regulate intracellular pH (pHi) and, for multicellular organisms, to regulate extracellular pH (pHo). pHi regulation depends on the opposing actions of plasma-membrane transporters that tend to increase pHi, and others that tend to decrease pHi. In addition, passive fluxes of uncharged species (e.g., CO2, NH3) and charged species (e.g., HCO3(-), [Formula: see text] ) perturb pHi. These movements not only influence one another, but also perturb the equilibria of a multitude of intracellular and extracellular buffers. Thus, even at the level of a single cell, perturbations in acid-base reactions, diffusion, and transport are so complex that it is impossible to understand them without a quantitative model. Here we summarize some mathematical models developed to shed light onto the complex interconnected events triggered by acids-base movements. We then describe a mathematical model of a spherical cells-which to our knowledge is the first one capable of handling a multitude of buffer reactions-that our team has recently developed to simulate changes in pHi and pHo caused by movements of acid-base equivalents across the plasma membrane of a Xenopus oocyte. Finally, we extend our work to a consideration of the effects of simultaneous CO2 and HCO3(-) influx into a cell, and envision how future models might extend to other cell types (e.g., erythrocytes) or tissues (e.g., renal proximal-tubule epithelium) important for whole-body pH homeostasis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. The acid/base profile of agrochemicals.

    Science.gov (United States)

    Manallack, D T

    2017-08-01

    Drug-likeness has long been studied in the pursuit of finding new medicines. Similarly, in the agrochemical field there is value in exploring the properties of the chemicals involved. Patterns that emerge can potentially influence future discovery campaigns to improve the probability of commercial success. In this study we investigate the acid/base properties and physicochemical characteristics of three classes of compounds: fungicides, herbicides and insecticides. In comparison with FDA-approved drugs, it was noted that the pesticides were generally smaller, possessed a neutral charge state and were more lipophilic. The results are discussed in the light of their intended targets.

  2. DISORDERS OF ACID-BASE STATE

    Directory of Open Access Journals (Sweden)

    P. F. Litvitskiy

    2011-01-01

    Full Text Available The lecture describes modern data on disorders of acid-base state (ABS: their types, etiology, key stages of pathogenesis, main symptoms, and principles of treatment. The first part of the lecture in present journal characterizes main conception, parameters of ABS in normal state, buffer systems, common mechanisms of BS shifts elimination, etiology and pathogenesis of gas-induced (respiratory disorders of ABS. The second part of the lecture in following journal will describe not gas-induced (metabolic, excretory and exogenous disorders of ABS and principles of their treatment.

  3. A General Simulator for Acid-Base Titrations

    Science.gov (United States)

    de Levie, Robert

    1999-07-01

    General formal expressions are provided to facilitate the automatic computer calculation of acid-base titration curves of arbitrary mixtures of acids, bases, and salts, without and with activity corrections based on the Davies equation. Explicit relations are also given for the buffer strength of mixtures of acids, bases, and salts.

  4. Assessing College Students' Understanding of Acid Base Chemistry Concepts

    Science.gov (United States)

    Wan, Yanjun Jean

    2014-01-01

    Typically most college curricula include three acid base models: Arrhenius', Bronsted-Lowry's, and Lewis'. Although Lewis' acid base model is generally thought to be the most sophisticated among these three models, and can be further applied in reaction mechanisms, most general chemistry curricula either do not include Lewis' acid base model, or…

  5. Using Willie's Acid-Base Box for Blood Gas Analysis

    Science.gov (United States)

    Dietz, John R.

    2011-01-01

    In this article, the author describes a method developed by Dr. William T. Lipscomb for teaching blood gas analysis of acid-base status and provides three examples using Willie's acid-base box. Willie's acid-base box is constructed using three of the parameters of standard arterial blood gas analysis: (1) pH; (2) bicarbonate; and (3) CO[subscript…

  6. Teaching Acid/Base Physiology in the Laboratory

    Science.gov (United States)

    Friis, Ulla G.; Plovsing, Ronni; Hansen, Klaus; Laursen, Bent G.; Wallstedt, Birgitta

    2010-01-01

    Acid/base homeostasis is one of the most difficult subdisciplines of physiology for medical students to master. A different approach, where theory and practice are linked, might help students develop a deeper understanding of acid/base homeostasis. We therefore set out to develop a laboratory exercise in acid/base physiology that would provide…

  7. Investigating Students' Reasoning about Acid-Base Reactions

    Science.gov (United States)

    Cooper, Melanie M.; Kouyoumdjian, Hovig; Underwood, Sonia M.

    2016-01-01

    Acid-base chemistry is central to a wide range of reactions. If students are able to understand how and why acid-base reactions occur, it should provide a basis for reasoning about a host of other reactions. Here, we report the development of a method to characterize student reasoning about acid-base reactions based on their description of…

  8. Mueller matrix microscope with a dual continuous rotating compensator setup and digital demodulation.

    Science.gov (United States)

    Arteaga, Oriol; Baldrís, Marta; Antó, Joan; Canillas, Adolf; Pascual, Esther; Bertran, Enric

    2014-04-01

    In this paper we describe a new Mueller matrix (MM) microscope that generalizes and makes quantitative the polarized light microscopy technique. In this instrument all the elements of the MU are simultaneously determined from the analysis in the frequency domain of the time-dependent intensity of the light beam at every pixel of the camera. The variations in intensity are created by the two compensators continuously rotating at different angular frequencies. A typical measurement is completed in a little over one minute and it can be applied to any visible wavelength. Some examples are presented to demonstrate the capabilities of the instrument.

  9. Mueller decomposition images for cervical tissue: potential for discriminating normal and dysplastic states.

    Science.gov (United States)

    Shukla, Prashant; Pradhan, Asima

    2009-02-02

    We report the potential of Mueller decomposition images to discriminate the normal against the dysplastic (precancerous) states in cervical tissue. It is observed that in the epithelium region, depolarization power is sensitive to morphological changes during progression from normal to dysplastic state while retardance and diattenuation do not show any significant change. These morphological changes have been correlated with the microscopic images of the tissues. In contrast, it is the retardance which reveals the morphological changes around the stromal region. Additionally, we have evaluated the arithmetic mean of depolarization power and retardance from their respective decomposed images and have shown that this parameter has a potential to discriminate normal tissues against dysplastic ones.

  10. Very forward jet, Mueller Navelet jets and jet gap jet measurements in CMS

    CERN Document Server

    Cerci, Salim

    2018-01-01

    The measurements of very forward jet, Mueller-Navelet jets and jet-gap-jet events are presented for different collision energies. The analyses are based on data collected with the CMS detector at the LHC. Jets are defined through the anti-$k_\\mathrm{t}$ clustering algorithm for different cone sizes. Jet production studies provide stringent tests of quantum chromodynamics (QCD) and contribute to tune Monte Carlo (MC) simulations and phenomenological models. The measurements are compared to predictions from various Monte Carlo event generators.

  11. Mueller matrix polarimetry on a Young's double-slit experiment analog.

    Science.gov (United States)

    Arteaga, Oriol; Ossikovski, Razvigor; Kuntman, Ertan; Kuntman, Mehmet A; Canillas, Adolf; Garcia-Caurel, Enric

    2017-10-01

    In this Letter we describe an experiment in which coherent light is sent through a calcite crystal that separates the photons by their polarization. The two beams are then let to superpose, and this recombined beam is used to measure the Mueller matrix of the system. Results are interpreted according to our recent formalism of coherent superposition in material media. This is the first experimental implementation of a Young's experiment with complete polarimetry, and it is demonstrated that our method can be used for the experimental synthesis of optical devices with on-demand optical properties.

  12. Differential Mueller matrix polarimetry technique for non-invasive measurement of glucose concentration on human fingertip.

    Science.gov (United States)

    Phan, Quoc-Hung; Lo, Yu-Lung

    2017-06-26

    A differential Mueller matrix polarimetry technique is proposed for obtaining non-invasive (NI) measurements of the glucose concentration on the human fingertip. The feasibility of the proposed method is demonstrated by detecting the optical rotation angle and depolarization index of tissue phantom samples containing de-ionized water (DI), glucose solutions with concentrations ranging from 0~500 mg/dL and 2% lipofundin. The results show that the extracted optical rotation angle increases linearly with an increasing glucose concentration, while the depolarization index decreases. The practical applicability of the proposed method is demonstrated by measuring the optical rotation angle and depolarization index properties of the human fingertips of healthy volunteers.

  13. Construction techniques and working principles of external cathode Geiger-Mueller counters

    International Nuclear Information System (INIS)

    Sevegnani, Francisco Xavier

    1996-01-01

    In this paper, the construction technique and working principles of the external cathode Geiger-Mueller counter are described in detail. During the analysis of the behavior of these counters a new phenomena was observed, related to an increase int he background rate with the applied voltage. The experiments have also shown that the pulse amplitude of those counters decreases exponentially with the counting rate. The counters built with the techniques described in this paper has shown plateaus of about 1400 V with slope of 0,8%/100 V. (author)

  14. Mueller-matrix of laser-induced autofluorescence of polycrystalline films of dried peritoneal fluid in diagnostics of endometriosis

    Science.gov (United States)

    Ushenko, Yuriy A.; Koval, Galina D.; Ushenko, Alexander G.; Dubolazov, Olexander V.; Ushenko, Vladimir A.; Novakovskaia, Olga Yu.

    2016-07-01

    This research presents investigation results of the diagnostic efficiency of an azimuthally stable Mueller-matrix method of analysis of laser autofluorescence of polycrystalline films of dried uterine cavity peritoneal fluid. A model of the generalized optical anisotropy of films of dried peritoneal fluid is proposed in order to define the processes of laser autofluorescence. The influence of complex mechanisms of both phase (linear and circular birefringence) and amplitude (linear and circular dichroism) anisotropies is taken into consideration. The interconnections between the azimuthally stable Mueller-matrix elements characterizing laser autofluorescence and different mechanisms of optical anisotropy are determined. The statistical analysis of coordinate distributions of such Mueller-matrix rotation invariants is proposed. Thereupon the quantitative criteria (statistic moments of the first to the fourth order) of differentiation of polycrystalline films of dried peritoneal fluid, group 1 (healthy donors) and group 2 (uterus endometriosis patients), are determined.

  15. Physiological roles of acid-base sensors.

    Science.gov (United States)

    Levin, Lonny R; Buck, Jochen

    2015-01-01

    Acid-base homeostasis is essential for life. The macromolecules upon which living organisms depend are sensitive to pH changes, and physiological systems use the equilibrium between carbon dioxide, bicarbonate, and protons to buffer their pH. Biological processes and environmental insults are constantly challenging an organism's pH; therefore, to maintain a consistent and proper pH, organisms need sensors that measure pH and that elicit appropriate responses. Mammals use multiple sensors for measuring both intracellular and extracellular pH, and although some mammalian pH sensors directly measure protons, it has recently become apparent that many pH-sensing systems measure pH via bicarbonate-sensing soluble adenylyl cyclase.

  16. Cervical collagen imaging for determining preterm labor risks using a colposcope with full Mueller matrix capability

    Science.gov (United States)

    Stoff, Susan; Chue-Sang, Joseph; Holness, Nola A.; Gandjbakhche, Amir; Chernomordik, Viktor; Ramella-Roman, Jessica

    2016-02-01

    Preterm birth is a worldwide health issue, as the number one cause of infant mortality and neurological disorders. Although affecting nearly 10% of all births, an accurate, reliable diagnostic method for preterm birth has, yet, to be developed. The primary constituent of the cervix, collagen, provides the structural support and mechanical strength to maintain cervical closure, through specific organization, during fetal gestation. As pregnancy progresses, the disorganization of the cervical collagen occurs to allow eventual cervical pliability so the baby can be birthed through the cervical opening. This disorganization of collagen affects the mechanical properties of the cervix and, if the changes occur prematurely, may be a significant factor leading to preterm birth. The organization of collagen can be analyzed through the use of Mueller Matrix Polarimetric imaging of the characteristic birefringence of collagen. In this research, we have built a full Mueller Matrix Polarimetry attachment to a standard colposcope to enable imaging of human cervixes during standard prenatal exams at various stages of fetal gestation. Analysis of the polarimetric images provides information of quantity and organization of cervical collagen at specific gestational stages of pregnancy. This quantitative information may provide an indication of risk of preterm birth.

  17. Traceable Mueller polarimetry and scatterometry for shape reconstruction of grating structures

    Science.gov (United States)

    Hansen, Poul-Erik; Madsen, Morten H.; Lehtolahti, Joonas; Nielsen, Lars

    2017-11-01

    Dimensional measurements of multi-patterned transmission gratings with a mixture of long and small periods are great challenges for optical metrology today. It is a further challenge when the aspect ratio of the structures is high, that is, when the height of structures is larger than the pitch. Here we consider a double patterned transmission grating with pitches of 500 nm and 20 000 nm. For measuring the geometrical properties of double patterned transmission grating we use a combined spectroscopic Mueller polarimetry and scatterometry setup. For modelling the experimentally obtained data we rigorously compute the scattering signal by solving Maxwell's equations using the RCWA method on a supercell structure. We also present a new method for analyzing the Mueller polarimetry parameters that performs the analysis in the measured variables. This new inversion method for finding the best fit between measured and calculated values are tested on silicon gratings with periods from 300 to 600 nm. The method is shown to give results within the expanded uncertainty of reference AFM measurements. The application of the new inversion method and the supercell structure to the double patterned transmission grating gives best estimates of dimensional quantities that are in fair agreement with those derived from local AFM measurements

  18. Stokes-Mueller matrix polarimetry technique for circular dichroism/birefringence sensing with scattering effects.

    Science.gov (United States)

    Phan, Quoc-Hung; Lo, Yu-Lung

    2017-04-01

    A surface plasmon resonance (SPR)-enhanced method is proposed for measuring the circular dichroism (CD), circular birefringence (CB), and degree of polarization (DOP) of turbid media using a Stokes–Mueller matrix polarimetry technique. The validity of the analytical model is confirmed by means of numerical simulations. The simulation results show that the proposed detection method enables the CD and CB properties to be measured with a resolution of 10 ? 4 refractive index unit (RIU) and 10 ? 5 ?? RIU , respectively, for refractive indices in the range of 1.3 to 1.4. The practical feasibility of the proposed method is demonstrated by detecting the CB/CD/DOP properties of glucose–chlorophyllin compound samples containing polystyrene microspheres. It is shown that the extracted CB value decreases linearly with the glucose concentration, while the extracted CD value increases linearly with the chlorophyllin concentration. However, the DOP is insensitive to both the glucose concentration and the chlorophyllin concentration. Consequently, the potential of the proposed SPR-enhanced Stokes–Mueller matrix polarimetry method for high-resolution CB/CD/DOP detection is confirmed. Notably, in contrast to conventional SPR techniques designed to detect relative refractive index changes, the SPR technique proposed in the present study allows absolute measurements of the optical properties (CB/CD/DOP) to be obtained.

  19. Mueller matrix polarimetry on plasma sprayed thermal barrier coatings for porosity measurement.

    Science.gov (United States)

    Luo, David A; Barraza, Enrique T; Kudenov, Michael W

    2017-12-10

    Yttria-stabilized zirconia (YSZ) is the most widely used material for thermal plasma sprayed thermal barrier coatings (TBCs) used to protect gas turbine engine parts in demanding operation environments. The superior material properties of YSZ coatings are related to their internal porosity level. By quantifying the porosity level, tighter control on the spraying process can be achieved to produce reliable coatings. Currently, destructive measurement methods are widely used to measure the porosity level. In this paper, we describe a novel nondestructive approach that is applicable to classify the porosity level of plasma sprayed YSZ TBCs via Mueller matrix polarimetry. A rotating retarder Mueller matrix polarimeter was used to measure the polarization properties of the plasma sprayed YSZ coatings with different porosity levels. From these measurements, it was determined that a sample's measured depolarization ratio is dependent on the sample's surface roughness and porosity level. To this end, we correlate the depolarization ratio with the samples' surface roughness, as measured by a contact profilometer, as well as the total porosity level, in percentage measured using a micrograph and stereological analysis. With the use of this technique, a full-field and rapid measurement of porosity level can be achieved.

  20. Comparison of Rosco Neo-Sensitabs with Oxoid paper disks in EUCAST disk diffusion antimicrobial susceptibility testing on Mueller-Hinton agar

    DEFF Research Database (Denmark)

    Justesen, U S; Acar, Ziyap; Olsson, K

    2013-01-01

    This study compared Neo-Sensitabs with Oxoid paper disks using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) disk diffusion antimicrobial susceptibility test on Mueller-Hinton agar. The EUCAST-recommended quality control strains (Escherichia coli ATCC 25922, Pseudomonas...... paper disks for EUCAST disk diffusion antimicrobial susceptibility testing on Mueller-Hinton agar....

  1. Drug-induced acid-base disorders.

    Science.gov (United States)

    Kitterer, Daniel; Schwab, Matthias; Alscher, M Dominik; Braun, Niko; Latus, Joerg

    2015-09-01

    The incidence of acid-base disorders (ABDs) is high, especially in hospitalized patients. ABDs are often indicators for severe systemic disorders. In everyday clinical practice, analysis of ABDs must be performed in a standardized manner. Highly sensitive diagnostic tools to distinguish the various ABDs include the anion gap and the serum osmolar gap. Drug-induced ABDs can be classified into five different categories in terms of their pathophysiology: (1) metabolic acidosis caused by acid overload, which may occur through accumulation of acids by endogenous (e.g., lactic acidosis by biguanides, propofol-related syndrome) or exogenous (e.g., glycol-dependant drugs, such as diazepam or salicylates) mechanisms or by decreased renal acid excretion (e.g., distal renal tubular acidosis by amphotericin B, nonsteroidal anti-inflammatory drugs, vitamin D); (2) base loss: proximal renal tubular acidosis by drugs (e.g., ifosfamide, aminoglycosides, carbonic anhydrase inhibitors, antiretrovirals, oxaliplatin or cisplatin) in the context of Fanconi syndrome; (3) alkalosis resulting from acid and/or chloride loss by renal (e.g., diuretics, penicillins, aminoglycosides) or extrarenal (e.g., laxative drugs) mechanisms; (4) exogenous bicarbonate loads: milk-alkali syndrome, overshoot alkalosis after bicarbonate therapy or citrate administration; and (5) respiratory acidosis or alkalosis resulting from drug-induced depression of the respiratory center or neuromuscular impairment (e.g., anesthetics, sedatives) or hyperventilation (e.g., salicylates, epinephrine, nicotine).

  2. Acid-base status and changes in Swedish forest soils

    International Nuclear Information System (INIS)

    Karltun, Erik; Stendahl, Johan; Lundin, Lars

    2003-01-01

    In this paper we use data from the Swedish National Survey of Forest Soils and Vegetation (NSFSV) to evaluate the present acid-base status of forest soils to try to answer the following questions. Which role do anthropogenic and biological acidification play for the present acid-base status of the soil profile? What is the present acid-base status of Swedish forest soils and how large areas may be considered as severely acidified? Do the current tendencies in soil acid-base status correspond with the positive development in surface waters?

  3. Use of Mueller matrix polarimetry and optical coherence tomography in the characterization of cervical collagen anisotropy

    Science.gov (United States)

    Chue-Sang, Joseph; Bai, Yuqiang; Stoff, Susan; Gonzalez, Mariacarla; Holness, Nola; Gomes, Jefferson; Jung, Ranu; Gandjbakhche, Amir; Chernomordik, Viktor V.; Ramella-Roman, Jessica C.

    2017-08-01

    Preterm birth (PTB) presents a serious medical health concern throughout the world. There is a high incidence of PTB in both developed and developing countries ranging from 11% to 15%, respectively. Recent research has shown that cervical collagen orientation and distribution changes during pregnancy may be useful in predicting PTB. Polarization imaging is an effective means to measure optical anisotropy in birefringent materials, such as the cervix's extracellular matrix. Noninvasive, full-field Mueller matrix polarimetry (MMP) imaging methodologies, and optical coherence tomography (OCT) imaging were used to assess cervical collagen content and structure in nonpregnant porcine cervices. We demonstrate that the highly ordered structure of the nonpregnant porcine cervix can be observed with MMP. Furthermore, when utilized ex vivo, OCT and MMP yield very similar results with a mean error of 3.46% between the two modalities.

  4. Mueller-Navelet jets in next-to-leading order BFKL. Theory versus experiment

    Energy Technology Data Exchange (ETDEWEB)

    Caporale, F.; Murdaca, B.; Papa, A. [Universita della Calabria, Dipartimento di Fisica, Cosenza (Italy); Gruppo collegato di Cosenza, Istituto Nazionale di Fisica Nucleare, Cosenza (Italy); Ivanov, D.Yu. [Sobolev Institute of Mathematics and Novosibirsk State University, Novosibirsk (Russian Federation)

    2014-10-15

    We study, within QCD collinear factorization and including BFKL resummation at the next-to-leading order, the production of Mueller-Navelet jets at LHC with center-of-mass energy of 7 TeV. The adopted jet vertices are calculated in the approximation of a small aperture of the jet cone in the pseudorapidity-azimuthal angle plane. We consider several representations of the dijet cross section, differing only beyond the next-to-leading order, to calculate a few observables related with this process. We use various methods of optimization to fix the energy scales entering the perturbative calculation and compare our results with the experimental data from the CMS collaboration. (orig.)

  5. Design of a portable dose rate detector based on a double Geiger-Mueller counter

    Science.gov (United States)

    Wang, Peng; Tang, Xiao-Bin; Gong, Pin; Huang, Xi; Wen, Liang-Sheng; Han, Zhen-Yang; He, Jian-Ping

    2018-01-01

    A portable dose rate detector was designed to monitor radioactive pollution and radioactive environments. The portable dose detector can measure background radiation levels (0.1 μSv/h) to nuclear accident radiation levels (>10 Sv/h). Both automatic switch technology of a double Geiger-Mueller counter and time-to-count technology were adopted to broaden the measurement range of the instrument. Global positioning systems and the 3G telecommunication protocol were installed to prevent radiation damage to the human body. In addition, the Monte Carlo N-Particle code was used to design the thin layer of metal for energy compensation, which was used to flatten energy response The portable dose rate detector has been calibrated by the standard radiation field method, and it can be used alone or in combination with additional radiation detectors.

  6. Silicate emission feature in the spectrum of comet Mueller 1993a

    Science.gov (United States)

    Hanner, Martha S.; Hackwell, John A.; Russell, Ray W.; Lynch, David K.

    1994-01-01

    An 8- to 13-micron spectrum of comet Mueller 1993a, a dynamically new comet, was acquired when the comet was at R = 2 AU. Strong, structured silicate emission is present, closely resembling that seen in Comet P/Halley at smaller R. For the first time in a new comet, the 11.2-micron peak of crystalline olivine was detected, demonstrating that crystalline olivine particles were widespread in the solar nebula. Crystalline olivine particles could have formed in the inner protosolar nebula at temperatures greater than 1200 K; extensive radial mixing would have been required to transport these grains to the region of comet formation. Either there was more radial mixing in the solar nebula than some current theories predict or the olivine grains have a presolar origin.

  7. Modeling Transmission and Reflection Mueller Matrices of Dielectric Half-Wave Plates

    Science.gov (United States)

    Salatino, Maria; de Bernardis, Paolo; Masi, Silvia

    2017-02-01

    We present a simple analytical model describing multiple reflections in dielectric and optically active waveplates, for both normal and slant incidence, including absorption. We compute from first principles the transmission and reflection Mueller matrices of the waveplate. The model is used to simulate the performance of a Stokes polarimeter for mm-waves, in the framework of current attempts to precisely measure the linear polarization of the Cosmic Microwave Background (CMB). We study the spectral response of these optical devices, taking into account band and angle averaging effects and confirm the presence of a much richer spectral dependence than in an ideal phase retarder. We also present the matrix elements for the reflection matrix, which is useful to estimate systematic effects in some polarimeter configurations. The formulas we have derived can be used to quickly simulate the performance of future CMB polarimeters.

  8. Optical characterization of porcine articular cartilage using a polarimetry technique with differential Mueller matrix formulism.

    Science.gov (United States)

    Chang, Ching-Min; Lo, Yu-Lung; Tran, Nghia-Khanh; Chang, Yu-Jen

    2018-03-20

    A method is proposed for characterizing the optical properties of articular cartilage sliced from a pig's thighbone using a Stokes-Mueller polarimetry technique. The principal axis angle, phase retardance, optical rotation angle, circular diattenuation, diattenuation axis angle, linear diattenuation, and depolarization index properties of the cartilage sample are all decoupled in the proposed analytical model. Consequently, the accuracy and robustness of the extracted results are improved. The glucose concentration, collagen distribution, and scattering properties of samples from various depths of the articular cartilage are systematically explored via an inspection of the related parameters. The results show that the glucose concentration and scattering effect are both enhanced in the superficial region of the cartilage. By contrast, the collagen density increases with an increasing sample depth.

  9. Use of Mueller matrix polarimetry and optical coherence tomography in the characterization of cervical collagen anisotropy.

    Science.gov (United States)

    Chue-Sang, Joseph; Bai, Yuqiang; Stoff, Susan; Gonzalez, Mariacarla; Holness, Nola; Gomes, Jefferson; Jung, Ranu; Gandjbakhche, Amir; Chernomordik, Viktor V; Ramella-Roman, Jessica C

    2017-08-01

    Preterm birth (PTB) presents a serious medical health concern throughout the world. There is a high incidence of PTB in both developed and developing countries ranging from 11% to 15%, respectively. Recent research has shown that cervical collagen orientation and distribution changes during pregnancy may be useful in predicting PTB. Polarization imaging is an effective means to measure optical anisotropy in birefringent materials, such as the cervix's extracellular matrix. Noninvasive, full-field Mueller matrix polarimetry (MMP) imaging methodologies, and optical coherence tomography (OCT) imaging were used to assess cervical collagen content and structure in nonpregnant porcine cervices. We demonstrate that the highly ordered structure of the nonpregnant porcine cervix can be observed with MMP. Furthermore, when utilized ex vivo, OCT and MMP yield very similar results with a mean error of 3.46% between the two modalities. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  10. Mueller-matrix ellipsometry studies of optically active structures in scarab beetles

    Directory of Open Access Journals (Sweden)

    Arwin H.

    2010-06-01

    Full Text Available The complexity of multilayers, photonic crystals, metamaterials and other artificial materials has promoted the use of spectroscopic, variable angle, generalized and Mueller-matrix ellipsometry. Naturally occurring structures may show even higher complexity than artificial structures but with a more narrow range of constituent materials. Fascinating reflection properties result from intricate photonic structures in, for instance, the wing scales and cuticles of insects. Currently there is a large interest to explore such functional supramolecular architectures for exploitation in nanotechnology. In this study, Mueller-matrix spectroscopic ellipsometry is applied in the spectral range of 250 to 1000 nm to investigate optical response and structures of the cuticle of Scarab beetles of the Cetoniinae subfamily. The cuticle of Cetonia aurata (the rose chafer, la cétoine dorée is green with a metallic appearance and reflects left-handed circular/elliptically polarized light. It has been suggested that the polarization of this metallic gloss is caused by a helical structure in the chitinous cuticle. We find that the polarization effect is limited to the narrow spectral range 470-550 nm whereas for shorter or longer wavelengths the reflection properties are similar to those from a near-dielectric material. Model calculations and parameterization of the nanostructure employing a heliocoidal structure are discussed. As a comparison the polarization effects from light reflected from two other beetles will be presented. Coptomia laevis has a similar appearance as Cetonia aurata but has very different polarization properties. The golden Plusiotis argentiola has very interesting properties showing both left and right-handed polarization depending on incidence angle and wavelength.

  11. Mueller's Muscle Conjunctival Resection With Skin-Only Blepharoplasty: Effects on Eyelid and Eyebrow Position.

    Science.gov (United States)

    Moore, Grant H; Rootman, Daniel B; Karlin, Justin; Goldberg, Robert A

    2015-01-01

    To determine the effect of concurrent blepharoplasty and Mueller's muscle conjunctival resection (MMCR) surgery on eyelid position and eyebrow height. Clinical data from 274 eyes that met inclusion criteria for this study were reviewed. Mueller's muscle conjunctival resection surgery was performed alone in 198 eyes and was performed with concurrent blepharoplasty in 76 cases. In this study blepharoplasty consisted of only skin removal, leaving the muscle, fat, and tarsus intact. Preoperative and postoperative pupil to eyebrow, and eyelid margin to eyebrow distances were calculated and compared. Preoperative margin reflex distance 1 (MRD1) was similar for both groups of patients (p > 0.05) as was the postoperative MRD1 (p > 0.05). The change in MRD1 was similar between patients undergoing MMCR alone versus those undergoing MMCR with blepharoplasty (1.5 mm vs. 1.3 mm, respectively, p = 0.36). For similar amounts of tissue resection, the postoperative change in MRD1 was similar for patients undergoing MMCR-only surgery and MMCR with blepharoplasty (p > 0.05). Eyebrow height significantly decreased following both MMCR with blepharoplasty (0.73 mm, p < 0.05) and MMCR-only surgery (0.87 mm, p < 0.05), and this change in eyebrow height was not significantly different between the 2 groups. Combining MMCR surgery with skin-only blepharoplasty does not significantly alter eyelid height when compared with MMCR surgery alone for the correction of upper eyelid ptosis. This may assist in preoperative planning for combined MMCR with skin-only blepharoplasty.

  12. A Closer Look at Acid-Base Olfactory Titrations

    Science.gov (United States)

    Neppel, Kerry; Oliver-Hoyo, Maria T.; Queen, Connie; Reed, Nicole

    2005-01-01

    Olfactory titrations using raw onions and eugenol as acid-base indicators are reported. An in-depth investigation on olfactory titrations is presented to include requirements for potential olfactory indicators and protocols for using garlic, onions, and vanillin as acid-base olfactory indicators are tested.

  13. Snapshot Mueller matrix polarimetry by wavelength polarization coding and application to the study of switching dynamics in a ferroelectric liquid crystal cell.

    Directory of Open Access Journals (Sweden)

    Le Jeune B.

    2010-06-01

    Full Text Available This paper describes a snapshot Mueller matrix polarimeter by wavelength polarization coding. This device is aimed at encoding polarization states in the spectral domain through use of a broadband source and high-order retarders. This allows one to measure a full Mueller matrix from a single spectrum whose acquisition time only depends on the detection system aperture. The theoretical fundamentals of this technique are developed prior to validation by experiments. The setup calibration is described as well as optimization and stabilization procedures. Then, it is used to study, by time-resolved Mueller matrix polarimetry, the switching dynamics in a ferroelectric liquid crystal cell.

  14. Teaching acid/base physiology in the laboratory

    DEFF Research Database (Denmark)

    Friis, Ulla G; Plovsing, Ronni; Hansen, Klaus

    2010-01-01

    Acid/base homeostasis is one of the most difficult subdisciplines of physiology for medical students to master. A different approach, where theory and practice are linked, might help students develop a deeper understanding of acid/base homeostasis. We therefore set out to develop a laboratory...... exercise in acid/base physiology that would provide students with unambiguous and reproducible data that clearly would illustrate the theory in practice. The laboratory exercise was developed to include both metabolic acidosis and respiratory alkalosis. Data were collected from 56 groups of medical...

  15. [Acid-base imbalance in acute obstructive uropathies].

    Science.gov (United States)

    Belyĭ, L E

    2007-01-01

    The aim of this study was to evaluate impairment of acid-base balance (ABB) in acute obstructive uropathies. Evaluation of acid-base balance was performed by pH, partial carbon dioxide pressure, plasma bicarbonate concentration, buffer bases, basis excess, hydrogen ion concentration. An automatic gas analyzer was used, plasma anion gap was calculated. Characteristic ABB alterations in different acute obstructive uropathies were detected. Acidotic shifts in acute obstruction of the upper urinary tracts and its inflammatory complications were assessed pathophysiologically. A comparative study of pathological acid-base disorders in acute supra- and infravesical obstructive uropathies was performed.

  16. Quantitative assessment of submicron scale anisotropy in tissue multifractality by scattering Mueller matrix in the framework of Born approximation

    Science.gov (United States)

    Das, Nandan Kumar; Dey, Rajib; Chakraborty, Semanti; Panigrahi, Prasanta K.; Meglinski, Igor; Ghosh, Nirmalya

    2018-04-01

    A number of tissue-like disordered media exhibit local anisotropy of scattering in the scaling behavior. Scaling behavior contains wealth of fractal or multifractal properties. We demonstrate that the spatial dielectric fluctuations in a sample of biological tissue exhibit multifractal anisotropy. Multifractal anisotropy encoded in the wavelength variation of the light scattering Mueller matrix and manifesting as an intriguing spectral diattenuation effect. We developed an inverse method for the quantitative assessment of the multifractal anisotropy. The method is based on the processing of relevant Mueller matrix elements in Fourier domain by using Born approximation, followed by the multifractal analysis. The approach promises for probing subtle micro-structural changes in biological tissues associated with the cancer and precancer, as well as for non-destructive characterization of a wide range of scattering materials.

  17. As the crack in the Geiger counter came. Historical scientific analysis and didactic aspects of the Geiger-Mueller counting tube

    International Nuclear Information System (INIS)

    Korff, Sebastian

    2014-01-01

    This thesis studies the creation and establishment history of this instrument called first electron counting tube in the years 1928 and 1929. It deals thereby with the last two years of the common work of Hans Geiger and Walter Mueller, from which the measuring instrument later renamed to Geiger-Mueller counting tube. The results of this scientific case study are didactically worked out and made usable for the teaching of physics in the school.

  18. Mueller-Navelet jets at 13 TeV LHC: dependence on dynamic constraints in the central rapidity region

    Energy Technology Data Exchange (ETDEWEB)

    Celiberto, F.G.; Papa, A. [Universita della Calabria, Dipartimento di Fisica, Cosenza (Italy); Gruppo collegato di Cosenza, Istituto Nazionale di Fisica Nucleare, Cosenza (Italy); Ivanov, D.Yu. [Sobolev Institute of Mathematics, Novosibirsk (Russian Federation); Novosibirsk State University, Novosibirsk (Russian Federation); Murdaca, B. [Gruppo collegato di Cosenza, Istituto Nazionale di Fisica Nucleare, Cosenza (Italy)

    2016-04-15

    We study the production of Mueller-Navelet jets at 13 TeV LHC, within collinear factorization and including the BFKL resummation of energy logarithms in the next-to-leading approximation. We calculate several azimuthal correlations for different values of the rapidity separation Y between the two jets and evaluate the effect of excluding those events where, for a given Y, one of the two jets is produced in the central region. (orig.)

  19. Optical fiber-based full Mueller polarimeter for endoscopic imaging using a two-wavelength simultaneous measurement method.

    Science.gov (United States)

    Vizet, Jérémy; Manhas, Sandeep; Tran, Jacqueline; Validire, Pierre; Benali, Abdelali; Garcia-Caurel, Enric; Pierangelo, Angelo; De Martino, Antonello; Pagnoux, Dominique

    2016-07-01

    This paper reports a technique based on spectrally differential measurement for determining the full Mueller matrix of a biological sample through an optical fiber. In this technique, two close wavelengths were used simultaneously, one for characterizing the fiber and the other for characterizing the assembly of fiber and sample. The characteristics of the fiber measured at one wavelength were used to decouple its contribution from the measurement on the assembly of fiber and sample and then to extract sample Mueller matrix at the second wavelength. The proof of concept was experimentally validated by measuring polarimetric parameters of various calibrated optical components through the optical fiber. Then, polarimetric images of histological cuts of human colon tissues were measured, and retardance, diattenuation, and orientation of the main axes of fibrillar regions were displayed. Finally, these images were successfully compared with images obtained by a free space Mueller microscope. As the reported method does not use any moving component, it offers attractive integration possibilities with an endoscopic probe.

  20. An Olfactory Indicator for Acid-Base Titrations.

    Science.gov (United States)

    Flair, Mark N.; Setzer, William N.

    1990-01-01

    The use of an olfactory acid-base indicator in titrations for visually impaired students is discussed. Potential olfactory indicators include eugenol, thymol, vanillin, and thiophenol. Titrations performed with each indicator with eugenol proved to be successful. (KR)

  1. The Bronsted-Lowery Acid-Base Concept.

    Science.gov (United States)

    Kauffman, George B.

    1988-01-01

    Gives the background history of the simultaneous discovery of acid-base relationships by Johannes Bronsted and Thomas Lowry. Provides a brief biographical sketch of each. Discusses their concept of acids and bases in some detail. (CW)

  2. Estudio comparativo del agar Iso-Sensitest y el agar Mueller-Hinton

    Directory of Open Access Journals (Sweden)

    Margaret Ordoñez Smith de Danies

    1993-12-01

    Full Text Available Se estudiaron 710 cepas bacterianas provenientes de diferentes muestras para comparar las zonas de inhibición de los diámetros obtenidos en agar Iso-Sensitest y el agar Mueller Hinton. Se realizaron bajo la técnica de difusión en disco de la NCCLS (Comité Nacional para los Estándares de Laboratorio Clínico. Estadísticamente, al analizar el chi-cuadrado de las muestras estudiadas, se observó una confiabilidad del 99%, por lo tanto no hay diferencia entre los dos medios de cultivo. En el agar Iso-Sensitest se obtuvo una mejor nitidez con los diámetros de los halos de inhibición, se encontró un 62,0% de mejor lectura o mayor visibilidad en los diámetros de las zonas de inhibición con los cultivos de Enterococcus sp., un 21,4% con el Staphylococcus aureus y 20,0% en el caso de la Providencia stuartii.

  3. Mapping local orientation of aligned fibrous scatterers for cancerous tissues using backscattering Mueller matrix imaging

    Science.gov (United States)

    He, Honghui; Sun, Minghao; Zeng, Nan; Du, E.; Liu, Shaoxiong; Guo, Yihong; Wu, Jian; He, Yonghong; Ma, Hui

    2014-10-01

    Polarization measurements are sensitive to the microstructure of tissues and can be used to detect pathological changes. Many tissues contain anisotropic fibrous structures. We obtain the local orientation of aligned fibrous scatterers using different groups of the backscattering Mueller matrix elements. Experiments on concentrically well-aligned silk fibers and unstained human papillary thyroid carcinoma tissues show that the m22, m33, m23, and m32 elements have better contrast but higher degeneracy for the extraction of orientation angles. The m12 and m13 elements show lower contrast, but allow us to determine the orientation angle for the fibrous scatterers along all directions. Moreover, Monte Carlo simulations based on the sphere-cylinder scattering model indicate that the oblique incidence of the illumination beam introduces some errors in the orientation angles obtained by both methods. Mapping the local orientation of anisotropic tissues may not only provide information on pathological changes, but can also give new leads to reduce the orientation dependence of polarization measurements.

  4. Ex vivo characterization of normal and adenocarcinoma colon samples by Mueller matrix polarimetry.

    Science.gov (United States)

    Ahmad, Iftikhar; Ahmad, Manzoor; Khan, Karim; Ashraf, Sumara; Ahmad, Shakil; Ikram, Masroor

    2015-05-01

    Mueller matrix polarimetry along with polar decomposition algorithm was employed for the characterization of ex vivo normal and adenocarcinoma human colon tissues by polarized light in the visible spectral range (425-725 nm). Six derived polarization metrics [total diattenuation (DT ), retardance (RT ), depolarization(ΔT ), linear diattenuation (DL), retardance (δ), and depolarization (ΔL)] were compared for normal and adenocarcinoma colon tissue samples. The results show that all six polarimetric properties for adenocarcinoma samples were significantly higher as compared to the normal samples for all wavelengths. The Wilcoxon rank sum test illustrated that total retardance is a good candidate for the discrimination of normal and adenocarcinoma colon samples. Support vector machine classification for normal and adenocarcinoma based on the four polarization properties spectra (ΔT , ΔL, RT ,and δ) yielded 100% accuracy, sensitivity, and specificity, while both DTa nd DL showed 66.6%, 33.3%, and 83.3% accuracy, sensitivity, and specificity, respectively. The combination of polarization analysis and given classification methods provides a framework to distinguish the normal and cancerous tissues.

  5. Application of a background-compensated Geiger-Mueller counter to a survey meter

    International Nuclear Information System (INIS)

    Mori, C.; Kumanomido, H.; Watanabe, T.

    1984-01-01

    A background-compensated Geiger-Mueller counter was used as a probe for a GM survey meter to obtain a net count rate of β-rays from a radioactive source in a quick survey. Although a background counting ratio between the two parts in the counter, front and rear, varied somewhat depending on the incident direction of background γ-rays, it was possible to compensate the background counts by subtracting a part of the rear counts, which were background counts, from the front counts, which contained β-ray counts and background counts. Undesirable small pulses generated during the recovering time after a full Geiger discharge were eliminated by an anticoincidence gating method. The survey meter with this counter and a differential ratemeter is useful for obtaining a net count rate of β-rays emitted from a surface radioactive-contamination or from a source being put near the window of the counter with nearly the same accuracy in half the measuring time as compared with conventional GM counters. (orig.)

  6. Acid-base homeostasis in the human system

    Science.gov (United States)

    White, R. J.

    1974-01-01

    Acid-base regulation is a cooperative phenomena in vivo with body fluids, extracellular and intracellular buffers, lungs, and kidneys all playing important roles. The present account is much too brief to be considered a review of present knowledge of these regulatory systems, and should be viewed, instead, as a guide to the elements necessary to construct a simple model of the mutual interactions of the acid-base regulatory systems of the body.

  7. Pattern of acid base abnormalities in critically ill patinets

    International Nuclear Information System (INIS)

    Ahmad, T.M.; Mehmood, A.; Malik, T.M.

    2015-01-01

    To find out the pattern of acid base abnormalities in critically ill patients in a tertiary care health facility. Study Design: A descriptive study. Place and Duration of Study: The study was carried out in the department of pathology, Combined Military Hospital Kharian from January 2013 to June 2013. Patients and Methods: Two hundred and fifty patients suffering from various diseases and presenting with exacerbation of their clinical conditions were studied. These patients were hospitalized and managed in acute care units of the hospital. Arterial blood gases were analysed to detect acid base status and their correlation with their clinical condition. Concomitant analysis of electrolytes was carried out. Tests related to concurrent illnesses e.g. renal and liver function tests, cardiac enzymes and plasma glucose were assayed by routine end point and kinetic methods. Standard reference materials were used to ensure internal quantify control of analyses. Results: Two hundred and fifteen patients out of 250 studied suffered from acid base disorders. Gender distribution showed a higher percentage of male patients and the mean age was 70.5 ± 17.4 years. Double acid base disorders were the commonest disorders (34%) followed by metabolic acidosis (30%). Anion gap was calculated to further stratify metabolic acidosis and cases of diabetic ketoacidosis were the commonest in this category (47%). Other simple acid base disorders were relatively less frequent. Delta bicarbonate was calculated to unmask the superimposition of respiratory alkalosis or acidosis with metabolic acidosis and metabolic alkalosis. Though triple acid base disorders were noted in a small percentage of cases (05%), but were found to be the most complicated and challenging. Mixed acid base disorders were associated with high mortality. Conclusion: A large number of critically ill patients manifested acid base abnormalities over the full spectrum of these disorders. Mixed acid base disorders were

  8. Assessment of acid-base balance. Stewart's approach.

    Science.gov (United States)

    Fores-Novales, B; Diez-Fores, P; Aguilera-Celorrio, L J

    2016-04-01

    The study of acid-base equilibrium, its regulation and its interpretation have been a source of debate since the beginning of 20th century. Most accepted and commonly used analyses are based on pH, a notion first introduced by Sorensen in 1909, and on the Henderson-Hasselbalch equation (1916). Since then new concepts have been development in order to complete and make easier the understanding of acid-base disorders. In the early 1980's Peter Stewart brought the traditional interpretation of acid-base disturbances into question and proposed a new method. This innovative approach seems more suitable for studying acid-base abnormalities in critically ill patients. The aim of this paper is to update acid-base concepts, methods, limitations and applications. Copyright © 2015 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  9. Renal acidification responses to respiratory acid-base disorders.

    Science.gov (United States)

    Madias, Nicolaos E

    2010-01-01

    Respiratory acid-base disorders are those abnormalities in acid-base equilibrium that are expressed as primary changes in the arterial carbon dioxide tension (PaCO2). An increase in PaCO2 (hypercapnia) acidifies body fluids and initiates the acid-base disturbance known as respiratory acidosis. By contrast, a decrease in PaCO2 (hypocapnia) alkalinizes body fluids and initiates the acid-base disturbance known as respiratory alkalosis. The impact on systemic acidity of these primary changes in PaCO2 is ameliorated by secondary, directional changes in plasma [HCO3¯] that occur in 2 stages. Acutely, hypercapnia or hypocapnia yields relatively small changes in plasma [HCO3¯] that originate virtually exclusively from titration of the body's nonbicarbonate buffers. During sustained hypercapnia or hypocapnia, much larger changes in plasma [HCO3¯] occur that reflect adjustments in renal acidification mechanisms. Consequently, the deviation of systemic acidity from normal is smaller in the chronic forms of these disorders. Here we provide an overview of the renal acidification responses to respiratory acid-base disorders. We also identify gaps in knowledge that require further research.

  10. Tailoring peritoneal dialysis fluid for optimal acid-base targets.

    Science.gov (United States)

    Feriani, Mariano

    2009-01-01

    Mild derangements of acid-base status are common features in peritoneal dialysis patients, metabolic acidosis being the most frequent alteration. One of the main tasks of dialysis is to correct these derangements and the target is the normalization of the acid-base parameters since they affect several organs and functions. Since factors affecting acid-base homeostasis are intrinsic characteristics of the individual patient (metabolic acid production, distribution space for bicarbonate, dialytic prescription, etc.), it is not surprising that only relatively few patients achieve the normal range. Only a certain modulation of buffer infusion by using different buffer concentrations in the dialysis fluid may ensure a good correction in a large percentage of patients.

  11. Assessing Acid-Base Status: Physiologic Versus Physicochemical Approach.

    Science.gov (United States)

    Adrogué, Horacio J; Madias, Nicolaos E

    2016-11-01

    The physiologic approach has long been used in assessing acid-base status. This approach considers acids as hydrogen ion donors and bases as hydrogen ion acceptors and the acid-base status of the organism as reflecting the interaction of net hydrogen ion balance with body buffers. In the physiologic approach, the carbonic acid/bicarbonate buffer pair is used for assessing acid-base status and blood pH is determined by carbonic acid (ie, Paco 2 ) and serum bicarbonate levels. More recently, the physicochemical approach was introduced, which has gained popularity, particularly among intensivists and anesthesiologists. This approach posits that the acid-base status of body fluids is determined by changes in the dissociation of water that are driven by the interplay of 3 independent variables: the sum of strong (fully dissociated) cation concentrations minus the sum of strong anion concentrations (strong ion difference); the total concentration of weak acids; and Paco 2 . These 3 independent variables mechanistically determine both hydrogen ion concentration and bicarbonate concentration of body fluids, which are considered as dependent variables. Our experience indicates that the average practitioner is familiar with only one of these approaches and knows very little, if any, about the other approach. In the present Acid-Base and Electrolyte Teaching Case, we attempt to bridge this knowledge gap by contrasting the physiologic and physicochemical approaches to assessing acid-base status. We first outline the essential features, advantages, and limitations of each of the 2 approaches and then apply each approach to the same patient presentation. We conclude with our view about the optimal approach. Copyright © 2016 National Kidney Foundation, Inc. All rights reserved.

  12. Characterizing the Effects of Washing by Different Detergents on the Wavelength-Scale Microstructures of Silk Samples Using Mueller Matrix Polarimetry

    Directory of Open Access Journals (Sweden)

    Yang Dong

    2016-08-01

    Full Text Available Silk fibers suffer from microstructural changes due to various external environmental conditions including daily washings. In this paper, we take the backscattering Mueller matrix images of silk samples for non-destructive and real-time quantitative characterization of the wavelength-scale microstructure and examination of the effects of washing by different detergents. The 2D images of the 16 Mueller matrix elements are reduced to the frequency distribution histograms (FDHs whose central moments reveal the dominant structural features of the silk fibers. A group of new parameters are also proposed to characterize the wavelength-scale microstructural changes of the silk samples during the washing processes. Monte Carlo (MC simulations are carried out to better understand how the Mueller matrix parameters are related to the wavelength-scale microstructure of silk fibers. The good agreement between experiments and simulations indicates that the Mueller matrix polarimetry and FDH based parameters can be used to quantitatively detect the wavelength-scale microstructural features of silk fibers. Mueller matrix polarimetry may be used as a powerful tool for non-destructive and in situ characterization of the wavelength-scale microstructures of silk based materials.

  13. Characterizing the Effects of Washing by Different Detergents on the Wavelength-Scale Microstructures of Silk Samples Using Mueller Matrix Polarimetry.

    Science.gov (United States)

    Dong, Yang; He, Honghui; He, Chao; Zhou, Jialing; Zeng, Nan; Ma, Hui

    2016-08-10

    Silk fibers suffer from microstructural changes due to various external environmental conditions including daily washings. In this paper, we take the backscattering Mueller matrix images of silk samples for non-destructive and real-time quantitative characterization of the wavelength-scale microstructure and examination of the effects of washing by different detergents. The 2D images of the 16 Mueller matrix elements are reduced to the frequency distribution histograms (FDHs) whose central moments reveal the dominant structural features of the silk fibers. A group of new parameters are also proposed to characterize the wavelength-scale microstructural changes of the silk samples during the washing processes. Monte Carlo (MC) simulations are carried out to better understand how the Mueller matrix parameters are related to the wavelength-scale microstructure of silk fibers. The good agreement between experiments and simulations indicates that the Mueller matrix polarimetry and FDH based parameters can be used to quantitatively detect the wavelength-scale microstructural features of silk fibers. Mueller matrix polarimetry may be used as a powerful tool for non-destructive and in situ characterization of the wavelength-scale microstructures of silk based materials.

  14. A quantitative and non-contact technique to characterise microstructural variations of skin tissues during photo-damaging process based on Mueller matrix polarimetry.

    Science.gov (United States)

    Dong, Yang; He, Honghui; Sheng, Wei; Wu, Jian; Ma, Hui

    2017-10-31

    Skin tissue consists of collagen and elastic fibres, which are highly susceptible to damage when exposed to ultraviolet radiation (UVR), leading to skin aging and cancer. However, a lack of non-invasive detection methods makes determining the degree of UVR damage to skin in real time difficult. As one of the fundamental features of light, polarization can be used to develop imaging techniques capable of providing structural information about tissues. In particular, Mueller matrix polarimetry is suitable for detecting changes in collagen and elastic fibres. Here, we demonstrate a novel, quantitative, non-contact and in situ technique based on Mueller matrix polarimetry for monitoring the microstructural changes of skin tissues during UVR-induced photo-damaging. We measured the Mueller matrices of nude mouse skin samples, then analysed the transformed parameters to characterise microstructural changes during the skin photo-damaging and self-repairing processes. Comparisons between samples with and without the application of a sunscreen showed that the Mueller matrix-derived parameters are potential indicators for fibrous microstructure in skin tissues. Histological examination and Monte Carlo simulations confirmed the relationship between the Mueller matrix parameters and changes to fibrous structures. This technique paves the way for non-contact evaluation of skin structure in cosmetics and dermatological health.

  15. Acids and bases solvent effects on acid-base strenght

    CERN Document Server

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  16. Acid-base disturbance in patients with cirrhosis

    DEFF Research Database (Denmark)

    Henriksen, Jens H; Bendtsen, Flemming; Møller, Søren

    2015-01-01

    PURPOSE: Acid-base disturbances were investigated in patients with cirrhosis in relation to hemodynamic derangement to analyze the hyperventilatory effects and the metabolic compensation. METHODS: A total of 66 patients with cirrhosis and 44 controls were investigated during a hemodynamic study......, and effects of unidentified ions (all Pacid-base disturbances could not be identified. CONCLUSION: Hypocapnic alkalosis is related to disease severity and hyperdynamic systemic circulation in patients with cirrhosis. The metabolic compensation includes...... alterations in serum albumin and water retention that may result in a delicate acid-base balance in these patients....

  17. Backscattering Mueller matrix for quasi-horizontally oriented ice plates of cirrus clouds: application to CALIPSO signals.

    Science.gov (United States)

    Borovoi, Anatoli; Konoshonkin, Alexander; Kustova, Natalia; Okamoto, Hajime

    2012-12-17

    A general view of the backscattering Mueller matrix for the quasi-horizontally oriented hexagonal ice crystals of cirrus clouds has been obtained in the case of tilted and scanning lidars. It is shown that the main properties of this matrix are caused by contributions from two qualitatively different components referred to the specular and corner-reflection terms. The numerical calculation of the matrix is worked out in the physical optics approximation. These matrices calculated for two wavelengths and two tilt angles (initial and present) of CALIPSO lidar are presented as a data bank. The depolarization and color ratios for these data have been obtained and discussed.

  18. A dipstick sensor for coulometric acid-base titrations

    NARCIS (Netherlands)

    Olthuis, Wouter; van der Schoot, B.H.; Chavez, F.; Bergveld, Piet

    1989-01-01

    By performing an acid-base titration by coulometric generation of OH− or H+ ions at an inert electrode in close proximity to the pH-sensitive gate of an ISFET, it is possible to determine the acid or base concentration of a solution using the ISFET as an indicator device for the equivalence point in

  19. Using Spreadsheets to Produce Acid-Base Titration Curves.

    Science.gov (United States)

    Cawley, Martin James; Parkinson, John

    1995-01-01

    Describes two spreadsheets for producing acid-base titration curves, one uses relatively simple cell formulae that can be written into the spreadsheet by inexperienced students and the second uses more complex formulae that are best written by the teacher. (JRH)

  20. Acid-Base Disorders--A Computer Simulation.

    Science.gov (United States)

    Maude, David L.

    1985-01-01

    Describes and lists a program for Apple Pascal Version 1.1 which investigates the behavior of the bicarbonate-carbon dioxide buffer system in acid-base disorders. Designed specifically for the preclinical medical student, the program has proven easy to use and enables students to use blood gas parameters to arrive at diagnoses. (DH)

  1. Dynamic Buffer Capacity in Acid?Base Systems

    OpenAIRE

    Micha?owska-Kaczmarczyk, Anna M.; Micha?owski, Tadeusz

    2015-01-01

    The generalized concept of ?dynamic? buffer capacity ? V is related to electrolytic systems of different complexity where acid?base equilibria are involved. The resulting formulas are presented in a uniform and consistent form. The detailed calculations are related to two Britton?Robinson buffers, taken as examples.

  2. Dynamic Buffer Capacity in Acid-Base Systems.

    Science.gov (United States)

    Michałowska-Kaczmarczyk, Anna M; Michałowski, Tadeusz

    The generalized concept of 'dynamic' buffer capacity β V is related to electrolytic systems of different complexity where acid-base equilibria are involved. The resulting formulas are presented in a uniform and consistent form. The detailed calculations are related to two Britton-Robinson buffers, taken as examples.

  3. Students' Understanding of Acids/Bases in Organic Chemistry Contexts

    Science.gov (United States)

    Cartrette, David P.; Mayo, Provi M.

    2011-01-01

    Understanding key foundational principles is vital to learning chemistry across different contexts. One such foundational principle is the acid/base behavior of molecules. In the general chemistry sequence, the Bronsted-Lowry theory is stressed, because it lends itself well to studying equilibrium and kinetics. However, the Lewis theory of…

  4. Development of an polarization sensitive Fourier domain optical coherence tomography and it utilization on the Mueller matrix determination

    International Nuclear Information System (INIS)

    Raele, Marcus Paulo

    2009-01-01

    This study approached theoretical and experimental aspects related with the development of a polarization sensitive, Fourier domain, optical coherence tomography system (PS-FD-OCT) and its utilization on the Mueller Matrix determination. This work began with a bibliographic revision, which describes since the early studies to the actual state of the art of the technique. The mathematical formalism of Fourier domain low coherence interferometry and light polarization was performed as well. Studies based on numerical simulations, of three different algorithm types, responsible to recover the scattering profile, were done. The implemented algorithms were: Direct Fourier Transform, Interpolation and zero-filling. By the end of the simulation study, was possible to conclude that the algorithm zero-filling 2N presented better characteristics when compared with the others. In the experimental part, firstly different OCT setups were assembled and measurements were done in order to verify aspects related with the theory. Then, using a polymeric sample, birefringence images were performed, which allowed determining the sample birefringence quantitatively. Finally, images taken of different polarization states were collected, and through then images related with the Mueller Matrix elements were calculated, which were analyzed individually. (author)

  5. Cuticle structure of the scarab beetle Cetonia aurata analyzed by regression analysis of Mueller-matrix ellipsometric data.

    Science.gov (United States)

    Arwin, Hans; Berlind, Torun; Johs, Blaine; Järrendahl, Kenneth

    2013-09-23

    Since one hundred years it is known that some scarab beetles reflect elliptically and near-circular polarized light as demonstrated by Michelson for the beetle Chrysina resplendens. The handedness of the polarization is in a majority of cases left-handed but also right-handed polarization has been found. In addition, brilliant colors with metallic shine are observed. The polarization and color effects are generated in the beetle exoskeleton, the so-called cuticle. The objective of this work is to demonstrate that structural parameters and materials optical functions of these photonic structures can be extracted by advanced modeling of spectral multi-angle Mueller-matrix data recorded from beetle cuticles. A dual-rotating compensator ellipsometer is used to record normalized Mueller-matrix data in the spectral range 400 - 800 nm at angles of incidence in the range 25-75°. Analysis of data measured on the scarab beetle Cetonia aurata are presented in detail. The model used in the analysis mimics a chiral nanostructure and is based on a twisted layered structure. Given the complexity of the nanostructure, an excellent fit between experimental and model data is achieved. The obtained model parameters are the spectral variation of the refractive indices of the cuticle layers and structural parameters of the chiral structure.

  6. Acid-base characteristics of powdered-activated-carbon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Reed, B.E. (West Virginia Univ., Morgantown (United States)); Jensen, J.N.; Matsumoto, M.R. (State Univ. of New York, Buffalo (United States))

    Adsorption of heavy metals onto activated carbon has been described using the surface-complex-formation (SCF) model, a chemical equilibrium model. The SCF model requires a knowledge of the amphoteric nature of activated carbon prior to metal adsorption modeling. In the past, a single-diprotic-acid-site model had been employed to describe the amphoteric nature of activated-carbon surfaces. During this study, the amphoteric nature of two powdered activated carbons were investigated, and a three-monoprotic site surface model was found to be a plausible alternative. The single-diprotic-acid-site and two-monoprotic-site models did not describe the acid-base behavior of the two carbons studied adequately. The two-diprotic site was acceptable for only one of the study carbons. The acid-base behavior of activated carbon surfaces seem to be best modeled as a series of weak monoprotic acids.

  7. [Acid-base status in patients treated with peritoneal dialysis].

    Science.gov (United States)

    Katalinić, Lea; Blaslov, Kristina; Pasini, Eva; Kes, Petar; Bašić-Jukić, Nikolina

    2014-04-01

    When compared to hemodialysis, peritoneal dialysis is very simple yet low cost method of renal replacement therapy. Series of studies have shown its superiority in preserving residual renal function, postponing uremic complications, maintaining the acid-base balance and achieving better post-transplant outcome in patients treated with this method. Despite obvious advantages, its role in the treatment of chronic kidney disease is still not as important as it should be. Metabolic acidosis is an inevitable complication associated with progressive loss of kidney function. Its impact on mineral and muscle metabolism, residual renal function, allograft function and anemia is very complex but can be successfully managed. The aim of our study was to evaluate the efficiency in preserving the acid-base balance in patients undergoing peritoneal dialysis at Zagreb University Hospital Center. Twenty-eight patients were enrolled in the study. The mean time spent on the treatment was 32.39 ± 43.43 months. Only lactate-buffered peritoneal dialysis fluids were used in the treatment. Acid-base balance was completely maintained in 73.07% of patients; 11.54% of patients were found in the state of mild metabolic acidosis, and the same percentage of patients were in the state of mild metabolic alkalosis. In one patient, mixed alkalosis with respiratory and metabolic component was present. The results of this study showed that acid-base balance could be maintained successfully in patients undergoing peritoneal dialysis, even only with lactate-buffered solutions included in the treatment, although they were continuously proclaimed as inferior in comparison with bicarbonate-buffered ones. In well educated and informed patients who carefully use this method, accompanied by the attentive and thorough care of their physicians, this method can provide quality continuous replacement of lost renal function as well as better quality of life.

  8. Electrochemistry of acid-base reactions in anhydrous hydrogen fluoride

    International Nuclear Information System (INIS)

    Masson, J.P.; Devynck, J.; Tremillon, B.

    1975-01-01

    Electrochemical studies were made in following media: water-HF mixtures, anhydrous HF and KF solutions in HF, solutions of the SbF5 type in HF. The acidity level of these solutions was evaluated using the R(H) functions based on the strehlow hypotheses. From the pH measurement in anhydrous HF, it was possible to get acid-base titration curves and pH buffers. The behavior of quinones in anhydrous HF is presented [fr

  9. Carbonic anhydrase 5 regulates acid-base homeostasis in zebrafish.

    Directory of Open Access Journals (Sweden)

    Ruben Postel

    Full Text Available The regulation of the acid-base balance in cells is essential for proper cellular homeostasis. Disturbed acid-base balance directly affects cellular physiology, which often results in various pathological conditions. In every living organism, the protein family of carbonic anhydrases regulate a broad variety of homeostatic processes. Here we describe the identification, mapping and cloning of a zebrafish carbonic anhydrase 5 (ca5 mutation, collapse of fins (cof, which causes initially a collapse of the medial fins followed by necrosis and rapid degeneration of the embryo. These phenotypical characteristics can be mimicked in wild-type embryos by acetazolamide treatment, suggesting that CA5 activity in zebrafish is essential for a proper development. In addition we show that CA5 regulates acid-base balance during embryonic development, since lowering the pH can compensate for the loss of CA5 activity. Identification of selective modulators of CA5 activity could have a major impact on the development of new therapeutics involved in the treatment of a variety of disorders.

  10. Acid-base transport by the renal proximal tubule.

    Science.gov (United States)

    Skelton, Lara A; Boron, Walter F; Zhou, Yuehan

    2010-01-01

    Each day, the kidneys filter 180 L of blood plasma, equating to some 4,300 mmol of the major blood buffer, bicarbonate (HCO3-). The glomerular filtrate enters the lumen of the proximal tubule (PT), and the majority of filtered HCO3- is reclaimed along the early (S1) and convoluted (S2) portions of the PT in a manner coupled to the secretion of H+ into the lumen. The PT also uses the secreted H+ to titrate non-HCO3- buffers in the lumen, in the process creating "new HCO3-" for transport into the blood. Thus, the PT - along with more distal renal segments - is largely responsible for regulating plasma [HCO3-]. In this review we first focus on the milestone discoveries over the past 50+ years that define the mechanism and regulation of acid-base transport by the proximal tubule. Further on in the review, we will summarize research still in progress from our laboratory, work that addresses the problem of how the PT is able to finely adapt to acid-base disturbances by rapidly sensing changes in basolateral levels of HCO3- and CO2 (but not pH), and thereby to exert tight control over the acid-base composition of the blood plasma.

  11. Acid-base disorders in calves with chronic diarrhea.

    Science.gov (United States)

    Bednarski, M; Kupczyński, R; Sobiech, P

    2015-01-01

    The aim of this study was to analyze disorders of acid-base balance in calves with chronic diarrhea caused by mixed, viral, bacterial and Cryptosporydium parvum infection. We compared results ob- tained with the classic model (Henderson-Hasselbalch) and strong ion approach (the Steward model). The study included 36 calves aged between 14 and 21 days. The calves were allocated to three groups: I - (control) non-diarrheic calves, group II - animals with compensated acid-base imbalance and group III calves with compensated acid-base disorders and hypoalbuminemia. Plasma concentrations of Na+, K+, Cl-, C12+, Mg2+, P, albumin and lactate were measured. In the classic model, acid-base balance was determined on the basis of blood pH, pCO2, HCO3-, BE and anion gap. In the strong ion model, strong ion difference (SID), effective strong anion difference, total plasma concentration of nonvolatile buffers (A(Tot)) and strong ion gap (SIG) were measured. The control calves and the animals from groups II and III did not differ significantly in terms of their blood pH. The plasma concentration of HCO3-, BE and partial pressure of CO2 in animals from the two groups with chronic diarrhea were significantly higher than those found in the controls. The highest BE (6.03 mmol/l) was documented in calves from group II. The animals from this group presented compensation resulted from activation of metabolic mechanisms. The calves with hypoal- buminemia (group III) showed lower plasma concentrations of albumin (15.37 g/L), Cl (74.94 mmol/L), Mg2+ (0.53 mmol/L), P (1.41 mmol/L) and higher value of anion gap (39.03 mmol/L). This group III presented significantly higher SID3 (71.89 mmol/L), SID7 (72.92 mmol/L) and SIG (43.53 mmol/L) values than animals from the remaining groups (P acid-base disturbance in these cases suggests that classic model have some limitations. This model can not be recommended for use whenever serum albumin or phosphate concentrations are markedly abnormal.

  12. The normal acid-base status of mice.

    Science.gov (United States)

    Iversen, Nina K; Malte, Hans; Baatrup, Erik; Wang, Tobias

    2012-03-15

    Rodent models are commonly used for various physiological studies including acid-base regulation. Despite the widespread use of especially genetic modified mice, little attention have been made to characterise the normal acid-base status in these animals in order to reveal proper control values. Furthermore, several studies report blood gas values obtained in anaesthetised animals. We, therefore, decided to characterise blood CO(2) binding characteristic of mouse blood in vitro and to characterise normal acid-base status in conscious BALBc mice. In vitro CO(2) dissociation curves, performed on whole blood equilibrated to various PCO₂ levels in rotating tonometers, revealed a typical mammalian pK' (pK'=7.816-0.234 × pH (r=0.34)) and a non-bicarbonate buffer capacity (16.1 ± 2.6 slyke). To measure arterial acid-base status, small blood samples were taken from undisturbed mice with indwelling catheters in the carotid artery. In these animals, pH was 7.391 ± 0.026, plasma [HCO(3)(-)] 18.4 ± 0.83 mM, PCO₂ 30.3 ± 2.1 mm Hg and lactate concentration 4.6 ± 0.7 mM. Our study, therefore, shows that mice have an arterial pH that resembles other mammals, although arterial PCO₂ tends to be lower than in larger mammals. However, pH from arterial blood sampled from mice anaesthetised with isoflurane was significantly lower (pH 7.239 ± 0.021), while plasma [HCO(3)(-)] was 18.5 ± 1.4 mM, PCO₂ 41.9 ± 2.9 mm Hg and lactate concentration 4.48 ± 0.67 mM. Furthermore, we measured metabolism and ventilation (V(E)) in order to determine the ventilation requirements (VE/VO₂) to answer whether small mammals tend to hyperventilate. We recommend, therefore, that studies on acid-base regulation in mice should be based on samples taken for indwelling catheters rather than cardiac puncture of terminally anaesthetised mice. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. High-energy resummation effects in the production of Mueller-Navelet di-jets at the LHC

    International Nuclear Information System (INIS)

    Dudoue, B.; Szymanowski, L.; Wallon, S.

    2016-01-01

    We study the production of two forward jets with a large interval of rapidity at hadron colliders, which was proposed by Mueller and Navelet as a possible test of the high energy dynamics of QCD, within a complete next-to-leading logarithm framework. We show that using the Brodsky-Lepage-Mackenzie procedure to fix the renormalization scale leads to a very good description of the recent CMS data at the LHC for the azimuthal correlations of the jets. We show that the inclusion of next-to-leading order corrections to the jet vertex significantly reduces the importance of energy-momentum non-conservation which is inherent to the BFKL approach, for an asymmetric jet configuration. Finally, we argue that the double parton scattering contribution is negligible in the kinematics of actual CMS measurements. (authors)

  14. History of Medical Understanding and Misunderstanding of Acid Base Balance

    Science.gov (United States)

    Aiken, Christopher Geoffrey Alexander

    2013-01-01

    To establish how controversies in understanding acid base balance arose, the literature on acid base balance was reviewed from 1909, when Henderson described how the neutral reaction of blood is determined by carbonic and organic acids being in equilibrium with an excess of mineral bases over mineral acids. From 1914 to 1930, Van Slyke and others established our acid base principles. They recognised that carbonic acid converts into bicarbonate all non-volatile mineral bases not bound by mineral acids and determined therefore that bicarbonate represents the alkaline reserve of the body and should be a physiological constant. They showed that standard bicarbonate is a good measure of acidosis caused by increased production or decreased elimination of organic acids. However, they recognised that bicarbonate improved low plasma bicarbonate but not high urine acid excretion in diabetic ketoacidosis, and that increasing pCO2 caused chloride to shift into cells raising plasma titratable alkali. Both indicate that minerals influence pH. In 1945 Darrow showed that hyperchloraemic metabolic acidosis in preterm infants fed milk with 5.7 mmol of chloride and 2.0 mmol of sodium per 100 kcal was caused by retention of chloride in excess of sodium. Similar findings were made but not recognised in later studies of metabolic acidosis in preterm infants. Shohl in 1921 and Kildeberg in 1978 presented the theory that carbonic and organic acids are neutralised by mineral base, where mineral base is the excess of mineral cations over anions and organic acid is the difference between mineral base, bicarbonate and protein anion. The degree of metabolic acidosis measured as base excess is determined by deviation in both mineral base and organic acid from normal. PMID:24179938

  15. Developing nucleic acid-based electrical detection systems

    Directory of Open Access Journals (Sweden)

    Gabig-Ciminska Magdalena

    2006-03-01

    Full Text Available Abstract Development of nucleic acid-based detection systems is the main focus of many research groups and high technology companies. The enormous work done in this field is particularly due to the broad versatility and variety of these sensing devices. From optical to electrical systems, from label-dependent to label-free approaches, from single to multi-analyte and array formats, this wide range of possibilities makes the research field very diversified and competitive. New challenges and requirements for an ideal detector suitable for nucleic acid analysis include high sensitivity and high specificity protocol that can be completed in a relatively short time offering at the same time low detection limit. Moreover, systems that can be miniaturized and automated present a significant advantage over conventional technology, especially if detection is needed in the field. Electrical system technology for nucleic acid-based detection is an enabling mode for making miniaturized to micro- and nanometer scale bio-monitoring devices via the fusion of modern micro- and nanofabrication technology and molecular biotechnology. The electrical biosensors that rely on the conversion of the Watson-Crick base-pair recognition event into a useful electrical signal are advancing rapidly, and recently are receiving much attention as a valuable tool for microbial pathogen detection. Pathogens may pose a serious threat to humans, animal and plants, thus their detection and analysis is a significant element of public health. Although different conventional methods for detection of pathogenic microorganisms and their toxins exist and are currently being applied, improvements of molecular-based detection methodologies have changed these traditional detection techniques and introduced a new era of rapid, miniaturized and automated electrical chip detection technologies into pathogen identification sector. In this review some developments and current directions in

  16. Acid-base properties of Baltic Sea dissolved organic matter

    Science.gov (United States)

    Hammer, Karoline; Schneider, Bernd; Kuliński, Karol; Schulz-Bull, Detlef E.

    2017-09-01

    Calculations related to the marine CO2 system that are based on alkalinity data may be strongly biased if the contributions of organic compounds are ignored. In coastal seas, concentrations of dissolved organic matter (DOM) are frequently high and alkalinity from inorganic compounds is low. In this study, based on measurements of total alkalinity, total CO2, and pH, we determined the organic alkalinity, Aorg, in water from the central Baltic Sea. The maximum Aorg measured in the surface mixed layer during the spring bloom was > 50 μmol/kg-SW but the Aorg decreased with depth and approached zero below the permanent halocline. This behavior could be attributed to the decreased pH of deeper water layers. The data were used to calculate the bulk dissociation constant, KDOM, for marine DOM and the fraction f of dissolved organic carbon (DOC) that acts as a carrier for acid-base functional groups. The p KDOM (7.27) agreed well with the value (7.34) previously estimated in a preliminary study of organic alkalinity in the Baltic Sea. The fraction of carbon atoms carrying acid-base groups was 17% and was somewhat higher than previously reported (12%). Spike experiments performed using artificial seawater and three different humic/fulvic substances tested whether the acid-base properties of these substances explain the results of our field study. Specifically, Aorg was determined at different concentrations (DOC) of the added humic/fulvic substances. The relationship between Aorg and the DOC concentrations indicated that humic/fulvic substances are more acidic (p KDOM < 6.5) than the bulk DOC natural occurring in the Baltic Sea.

  17. Acid-Base Balance in Uremic Rats with Vascular Calcification

    Directory of Open Access Journals (Sweden)

    Alan Peralta-Ramírez

    2014-07-01

    Full Text Available Background/Aims: Vascular calcification (VC, a major complication in humans and animals with chronic kidney disease (CKD, is influenced by changes in acid-base balance. The purpose of this study was to describe the acid-base balance in uremic rats with VC and to correlate the parameters that define acid-base equilibrium with VC. Methods: Twenty-two rats with CKD induced by 5/6 nephrectomy (5/6 Nx and 10 nonuremic control rats were studied. Results: The 5/6 Nx rats showed extensive VC as evidenced by a high aortic calcium (9.2 ± 1.7 mg/g of tissue and phosphorus (20.6 ± 4.9 mg/g of tissue content. Uremic rats had an increased pH level (7.57 ± 0.03 as a consequence of both respiratory (PaCO2 = 28.4 ± 2.1 mm Hg and, to a lesser degree, metabolic (base excess = 4.1 ± 1 mmol/l derangements. A high positive correlation between both anion gap (AG and strong ion difference (SID with aortic calcium (AG: r = 0.604, p = 0.02; SID: r = 0.647, p = 0.01 and with aortic phosphorus (AG: r = 0.684, p = 0.007; SID: r = 0.785, p = 0.01 was detected. Conclusions: In an experimental model of uremic rats, VC showed high positive correlation with AG and SID.

  18. A dipstick sensor for coulometric acid-base titrations

    OpenAIRE

    Olthuis, Wouter; van der Schoot, B.H.; Chavez, F.; Bergveld, Piet

    1989-01-01

    By performing an acid-base titration by coulometric generation of OH− or H+ ions at an inert electrode in close proximity to the pH-sensitive gate of an ISFET, it is possible to determine the acid or base concentration of a solution using the ISFET as an indicator device for the equivalence point in the titration curve. Typical values for the titration time are 0.1 to 10 s for acid or base concentrations ranging from 0.5 × 10−3 to 10 × 10−3 mol/l. By placing the counter electrode for the supp...

  19. Modelling of acid-base titration curves of mineral assemblages

    Directory of Open Access Journals (Sweden)

    Stamberg Karel

    2016-01-01

    Full Text Available The modelling of acid-base titration curves of mineral assemblages was studied with respect to basic parameters of their surface sites to be obtained. The known modelling approaches, component additivity (CA and generalized composite (GC, and three types of different assemblages (fucoidic sandstones, sedimentary rock-clay and bentonite-magnetite samples were used. In contrary to GC-approach, application of which was without difficulties, the problem of CA-one consisted in the credibility and accessibility of the parameters characterizing the individual mineralogical components.

  20. [Acid-base homeostasis: metabolic acidosis and metabolic alkalosis].

    Science.gov (United States)

    Dussol, Bertrand

    2014-07-01

    Acid-base homeostasis ensured by the kidneys, which maintain the equilibrium between proton generation by cellular metabolism and proton excretion in urine. This requirement is lifesaving because of the protons' ability to bind to anionic proteins in the extracellular space, modifying their structure and functions. The kidneys also regenerate bicarbonates. The kidney is not the sole organ in charge of maintaining blood pH in a very narrow range; lungs are also involved since they allow a large amount of volatile acid generated by cellular respiration to be eliminated. Copyright © 2014 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

  1. Advances in nucleic acid-based diagnostics of bacterial infections

    DEFF Research Database (Denmark)

    Barken, Kim Bundvig; Haagensen, Janus Anders Juul; Tolker-Nielsen, Tim

    2007-01-01

    Methods for rapid detection of infectious bacteria and antimicrobial-resistant pathogens have evolved significantly over the last decade. Many of the new procedures are nucleic acid-based and replace conventional diagnostic methods like culturing which is time consuming especially with fastidious...... of these pathogens is important to isolate patients and prevent further spreading of the diseases. Newly developed diagnostic procedures are superior with respect to turnaround time, sensitivity and specificity. Methods like multiplex real time PCR and different array-based technologies offer the possibility...

  2. Boronic acid-based autoligation of nucleic acids

    DEFF Research Database (Denmark)

    Barbeyron, R.; Vasseur, J.-J.; Smietana, M.

    2013-01-01

    Abstract: The development of synthetic systems displaying dynamic and adaptive characteristics is a formidable challenge with wide applications from biotechnology to therapeutics. Recently, we described a dynamic and programmable nucleic acid-based system relying on the formation of reversible...... boronate internucleosidic linkages. The DNA- or RNA-templated system comprises a 5′-ended boronic acid probe connecting a 3′-ended ribonucleosidic oligonucleotide partner. To explore the dominant factors that control the reversible linkage, we synthesized a series of 3′-end modified ribonucleotidic strands...

  3. A Computer-Based Simulation of an Acid-Base Titration

    Science.gov (United States)

    Boblick, John M.

    1971-01-01

    Reviews the advantages of computer simulated environments for experiments, referring in particular to acid-base titrations. Includes pre-lab instructions and a sample computer printout of a student's use of an acid-base simulation. Ten references. (PR)

  4. Molecular polarization potential maps of the nucleic acid bases

    International Nuclear Information System (INIS)

    Alkorta, I.; Perez, J.J.

    1996-01-01

    Ab initio calculations at the SCF level were carried out to compute the polarization potential map NM of the nucleic acid bases: cytosine, thymine, uracil, adedine, and guanine. For this purpose, the Dunning's 9s5p basis set contracted to a split-valence, was selected to perform the calculations. The molecular polarization potential (MPP) at each point was evaluated by the difference between the interaction energy of the molecule with a unit point charge and the molecular electrostatic potential (MEP) at that point. MEPS and MPPS for the different molecules were computed with a density of 5 points/Angstrom 2 on the van der Waals surface of each molecule, defined using the van der Waals radii. Due to the symmetry of the molecules, only half the points were computed. The total number of points calculated was 558 for cytosine, 621 for thymine, 526 for uracil, 666 for adenine, and 699 for guanine. The results of these calculations are analyzed in terms of their implications on the molecular interactions between pairs of nucleic acid bases. 23 refs., 5 figs., 1 tab

  5. Acid-base catalysis of N-[(morpholine)methylene]daunorubicin.

    Science.gov (United States)

    Krause, Anna; Jelińska, Anna; Cielecka-Piontek, Judyta; Klawitter, Maria; Zalewski, Przemysław; Oszczapowicz, Irena; Wąsowska, Małgorzata

    2012-08-01

    The stability of N-[(morpholine)methylene]-daunorubicin hydrochloride (MMD) was investigated in the pH range 0.44-13.54, at 313, 308, 303 and 298 K. The degradation of MMD as a result of hydrolysis is a pseudo-first-order reaction described by the following equation: ln c = ln c(0) - k(obs)• t. In the solutions of hydrochloric acid, sodium hydroxide, borate, acetate and phosphate buffers, k(obs) = k(pH) because general acid-base catalysis was not observed. Specific acid-base catalysis of MMD comprises the following reactions: hydrolysis of the protonated molecules of MMD catalyzed by hydrogen ions (k(1)) and spontaneous hydrolysis of MMD molecules other than the protonated ones (k(2)) under the influence of water. The total rate of the reaction is equal to the sum of partial reactions: k(pH) = k(1) • a(H)+ • f(1) + k(2) • f(2) where: k(1) is the second-order rate constant (mol(-1) l s(-1)) of the specific hydrogen ion-catalyzed degradation of the protonated molecules of MMD; k(2) is the pseudo-first-order rate constant (s(-1)) of the water-catalyzed degradation of MMD molecules other than the protonated ones, f(1) - f(2) are fractions of the compound. MMD is the most stable at approx. pH 2.5.

  6. How Do Undergraduate Students Conceptualize Acid-Base Chemistry? Measurement of a Concept Progression

    Science.gov (United States)

    Romine, William L.; Todd, Amber N.; Clark, Travis B.

    2016-01-01

    We developed and validated a new instrument, called "Measuring Concept progressions in Acid-Base chemistry" (MCAB) and used it to better understand the progression of undergraduate students' understandings about acid-base chemistry. Items were developed based on an existing learning progression for acid-base chemistry. We used the Rasch…

  7. Evaluating Interest in Acids-Bases: Development of an Acid-Base Interest Scale (ABIS) and Assessment of Pre-Service Science Teachers' Interest

    Science.gov (United States)

    Çiçek, Ö.; Ilhan, N.

    2017-01-01

    Students are more likely to be successful in topics they are interested in than others. This study aims to develop an Acid-Base Interest Scale (ABIS) and subsequently evaluate the interest of pre-service science teachers in acids-bases according to gender, years at the university, type of high school the pre-service science teachers attended, and…

  8. Ultrasonic and densimetric titration applied for acid-base reactions.

    Science.gov (United States)

    Burakowski, Andrzej; Gliński, Jacek

    2014-01-01

    Classical acoustic acid-base titration was monitored using sound speed and density measurements. Plots of these parameters, as well as of the adiabatic compressibility coefficient calculated from them, exhibit changes with the volume of added titrant. Compressibility changes can be explained and quantitatively predicted theoretically in terms of Pasynski theory of non-compressible hydrates combined with that of the additivity of the hydration numbers with the amount and type of ions and molecules present in solution. It also seems that this development could be applied in chemical engineering for monitoring the course of chemical processes, since the applied experimental methods can be carried out almost independently on the medium under test (harmful, aggressive, etc.).

  9. Acid-base transport in pancreas-new challenges

    DEFF Research Database (Denmark)

    Novak, Ivana; Haanes, Kristian Agmund; Wang, Jing

    2013-01-01

    Along the gastrointestinal tract a number of epithelia contribute with acid or basic secretions in order to aid digestive processes. The stomach and pancreas are the most extreme examples of acid (H+) and base (HCO-3) transporters, respectively. Nevertheless, they share the same challenges...... of transporting acid and bases across epithelia and effectively regulating their intracellular pH. In this review, we will make use of comparative physiology to enlighten the cellular mechanisms of pancreatic HCO-3 and fluid secretion, which is still challenging physiologists. Some of the novel transporters...... to consider in pancreas are the proton pumps (H-K-ATPases), as well as the calcium-activated K and Cl channels, such as K3.1 and TMEM16A/ANO1. Local regulators, such as purinergic signaling, fine-tune, and coordinate pancreatic secretion. Lastly, we speculate whether dys-regulation of acid-base transport...

  10. Mechanisms of acid-base regulation in peritoneal dialysis.

    Science.gov (United States)

    Sow, Amadou; Morelle, Johann; Hautem, Nicolas; Bettoni, Carla; Wagner, Carsten A; Devuyst, Olivier

    2017-11-22

    Peritoneal dialysis (PD) contributes to restore acid-base homeostasis in patients with end-stage renal disease. The transport pathways for buffers and carbon dioxide (CO2) across the peritoneal membrane remain poorly understood. Combining well-established PD protocols, whole-body plethysmography and renal function studies in mice, we investigated molecular mechanisms of acid-base regulation in PD, including the potential role of the water channel aquaporin-1 (AQP1). After instillation in peritoneal cavity, the pH of acidic dialysis solutions increased within minutes to rapidly equilibrate with blood pH, whereas the neutral pH of biocompatible solutions remained constant. Predictions from the three-pore model of peritoneal transport suggested that local production of HCO3- accounts at least in part for the changes in intraperitoneal pH observed with acidic solutions. Carbonic anhydrase (CA) isoforms were evidenced in the peritoneal membrane and their inhibition with acetazolamide significantly decreased local production of HCO3- and delayed changes in intraperitoneal pH. On the contrary, genetic deletion of AQP1 had no effect on peritoneal transport of buffers and diffusion of CO2. Besides intraperitoneal modifications, the use of acidic dialysis solutions enhanced acid excretion both at pulmonary and renal levels. These findings suggest that changes in intraperitoneal pH during PD are mediated by bidirectional buffer transport and by CA-mediated production of HCO3- in the membrane. The use of acidic solutions enhances acid excretion through respiratory and renal responses, which should be considered in patients with renal failure. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  11. Significance of Early Postoperative Eyelid Position on Late Postoperative Result in Mueller's Muscle Conjunctival Resection and External Levator Advancement Surgery.

    Science.gov (United States)

    Danesh, Jennifer; Ugradar, Shoaib; Goldberg, Robert; Joshi, Naresh; Rootman, Daniel B

    2018-01-09

    The purpose of this study was to determine whether advancement of the levator aponeurosis in external levator resection surgery or Mueller's muscle and conjunctiva in Mueller's muscle conjunctival resection (MMCR) surgery has a differential effect on variation in eyelid position during the postoperative period. In this retrospective observational cohort study, 2 groups of patients were defined. The first underwent MMCR surgery without tarsectomy by surgeon 1. The second underwent external levator resection without dissection posterior to the levator aponeurosis by surgeon 2. Marginal reflex distance (MRD1) was calculated based on digital photographs at baseline, 1 week postoperatively and at 3-month follow up. The primary outcome measure was change in MRD1 over time. The secondary outcome was defined as the proportion of patients with minimal early postoperative change (change of MRD1 less than 0.5 mm at 1 week postoperatively). Repeated measures analysis of variance, t test, and chi-square analyses were performed. Of the 114 eyes in the sample, there were 68 in the MMCR group and 46 in the external levator resection group. A significant interaction between group and time was noted (p MRD1 over time was different between the groups. Bonferroni corrected multiple comparisons yielded significant differences between each time point for MMCR surgery (p MRD1 was noted for the external levator resection group from the early to late postoperative visit. Comparing each time point across groups revealed significantly lower MRD1 for the MMCR group at the early postoperative visit (p MRD1 did not significantly differ between the groups. Regarding the secondary outcome, patients undergoing MMCR surgery were 3.7× as likely to demonstrate MRD1 at week 1 (p MRD1 increase >1 mm from the early postoperative to the late postoperative time points. Both external levator resection and MMCR can effectively elevate the eyelid in cases of primary involutional ptosis, and have similar

  12. Multiple-layered effective medium approximation approach to modeling environmental effects on alumina passivated highly porous silicon nanostructured thin films measured by in-situ Mueller matrix ellipsometry

    Science.gov (United States)

    Mock, Alyssa; Carlson, Timothy; VanDerslice, Jeremy; Mohrmann, Joel; Woollam, John A.; Schubert, Eva; Schubert, Mathias

    2017-11-01

    Optical changes in alumina passivated highly porous silicon slanted columnar thin films during controlled exposure to toluene vapor are reported. Electron-beam evaporation glancing angle deposition and subsequent atomic layer deposition are utilized to deposit alumina passivated nanostructured porous silicon thin films. In-situ Mueller matrix generalized spectroscopic ellipsometry in an environmental cell is then used to determine changes in optical properties of the nanostructured thin films by inspection of individual Mueller matrix elements, each of which exhibit sensitivity to adsorption. The use of a multiple-layered effective medium approximation model allows for accurate description of the inhomogeneous nature of toluene adsorption onto alumina passivated highly porous silicon slanted columnar thin films.

  13. Azimuthally invariant Mueller-matrix mapping of optically anisotropic layers of biological networks of blood plasma in the diagnosis of liver disease

    Science.gov (United States)

    Ushenko, A. G.; Dubolazov, A. V.; Ushenko, V. A.; Ushenko, Yu. A.; Sakhnovskiy, M. Y.; Pavlyukovich, O.; Pavlyukovich, N.; Novakovskaya, O.; Gorsky, M. P.

    2016-09-01

    The model of Mueller-matrix description of mechanisms of optical anisotropy that typical for polycrystalline layers of the histological sections of biological tissues and fluids - optical activity, birefringence, as well as linear and circular dichroism - is suggested. Within the statistical analysis distributions quantities of linear and circular birefringence and dichroism the objective criteria of differentiation of myocardium histological sections (determining the cause of death); films of blood plasma (liver pathology); peritoneal fluid (endometriosis of tissues of women reproductive sphere); urine (kidney disease) were determined. From the point of view of probative medicine the operational characteristics (sensitivity, specificity and accuracy) of the method of Mueller-matrix reconstruction of optical anisotropy parameters were found.

  14. In-situ Mueller matrix ellipsometry of silicon nanowires grown by plasma-enhanced vapor-liquid-solid method for radial junction solar cells

    Science.gov (United States)

    Mrazkova, Z.; Foldyna, M.; Misra, S.; Al-Ghzaiwat, M.; Postava, K.; Pištora, J.; Roca i Cabarrocas, P.

    2017-11-01

    In-situ Mueller matrix spectroscopic ellipsometry was applied for monitoring the silicon nanowire growth by plasma-enhanced vapor-liquid-solid method. The technique is proposed as a real-time, non-destructive, and non-invasive characterization of the deposition process in a plasma-enhanced chemical vapor deposition reactor. The data have been taken by spectrally resolved Mueller matrix ellipsometer every 1 min during the 8-10 min long nanowire growth process. We have developed an easy-to-apply optical model to fit the experimental data, which enables to study the evolution of the parameters of the structure during initial stages of the growth. The first results provide information about the effective deposition rate determined from the linear increase of the deposited silicon volume with the deposition time.

  15. Optimal configuration of partial Mueller matrix polarimeter for measuring the ellipsometric parameters in the presence of Poisson shot noise and Gaussian noise

    Science.gov (United States)

    Quan, Naicheng; Zhang, Chunmin; Mu, Tingkui

    2018-05-01

    We address the optimal configuration of a partial Mueller matrix polarimeter used to determine the ellipsometric parameters in the presence of additive Gaussian noise and signal-dependent shot noise. The numerical results show that, for the PSG/PSA consisting of a variable retarder and a fixed polarizer, the detection process immune to these two types of noise can be optimally composed by 121.2° retardation with a pair of azimuths ±71.34° and a 144.48° retardation with a pair of azimuths ±31.56° for four Mueller matrix elements measurement. Compared with the existing configurations, the configuration presented in this paper can effectively decrease the measurement variance and thus statistically improve the measurement precision of the ellipsometric parameters.

  16. Propagation velocity of an avalanche along the anode wire in a Geiger-Mueller counter filled with Q-gas at 1 ATM

    International Nuclear Information System (INIS)

    Matsuda, Kazunori; Sanada, Junpei

    1990-01-01

    Simple methods were applied to investigate the characteristics of a Geiger-Mueller counter with Q-gas flowing at 1 atm. The propagation velocity of the photon-aided avalanche along the anode wire depends linearly on the strength of the electric field in the counter. Its fluctuation (FWHM) as a function of distance between the source position and the end point is discussed. (orig.)

  17. Effect of temperature on the acid-base properties of the alumina surface: microcalorimetry and acid-base titration experiments.

    Science.gov (United States)

    Morel, Jean-Pierre; Marmier, Nicolas; Hurel, Charlotte; Morel-Desrosiers, Nicole

    2006-06-15

    Sorption reactions on natural or synthetic materials that can attenuate the migration of pollutants in the geosphere could be affected by temperature variations. Nevertheless, most of the theoretical models describing sorption reactions are at 25 degrees C. To check these models at different temperatures, experimental data such as the enthalpies of sorption are thus required. Highly sensitive microcalorimeters can now be used to determine the heat effects accompanying the sorption of radionuclides on oxide-water interfaces, but enthalpies of sorption cannot be extracted from microcalorimetric data without a clear knowledge of the thermodynamics of protonation and deprotonation of the oxide surface. However, the values reported in the literature show large discrepancies and one must conclude that, amazingly, this fundamental problem of proton binding is not yet resolved. We have thus undertaken to measure by titration microcalorimetry the heat effects accompanying proton exchange at the alumina-water interface at 25 degrees C. Based on (i) the surface sites speciation provided by a surface complexation model (built from acid-base titrations at 25 degrees C) and (ii) results of the microcalorimetric experiments, calculations have been made to extract the enthalpic variations associated respectively to first and second deprotonation of the alumina surface. Values obtained are deltaH1 = 80+/-10 kJ mol(-1) and deltaH2 = 5+/-3 kJ mol(-1). In a second step, these enthalpy values were used to calculate the alumina surface acidity constants at 50 degrees C via the van't Hoff equation. Then a theoretical titration curve at 50 degrees C was calculated and compared to the experimental alumina surface titration curve. Good agreement between the predicted acid-base titration curve and the experimental one was observed.

  18. Interoceanic occurrence of species of Aristocleidus Mueller, 1936 (Monogenoidea: Dactylogyridae) parasitizing the gills of gerreid fishes in the Neotropics.

    Science.gov (United States)

    Mendoza Franco, Edgar F; Violante-González, Juan; Roche, Dominique G

    2009-09-01

    During investigations of fish parasites in the Neotropics (including the state of Veracruz and the Yucatán Peninsula in the Gulf of Mexico, the Chautengo Lagoon on the Pacific coast of the state of Guerrero in Mexico, and Lake Gatun in the Panama Canal), three monogenoidean (Dactylogyridae) species were found parasitizing the gills of gerreids (Gerreidae): Aristocleidus hastatus Mueller, 1936, was recovered from Eugerres plumieri (Cuvier) and Diapterus auratus Ranzani in Veracruz, from D. auratus and Diapterus rhombeus (Cuvier) in Yucatán, from Eugerres brasilianus (Cuvier) in Panama (all new hosts and geographical records), and from D. peruvianus (Cuvier) and Gerres cinereus (Walbaum) in Guerrero; Aristocleidus lamothei Kritsky and Mendoza-Franco, 2008, was recovered from E. plumieri in Veracruz and from D. rhombeus in Yucatan (new hosts and geographical records), and Aristocleidus sp. was recovered from G. cinereus in Guerrero. Results from this study suggest that species of Aristocleidus exhibit wide host specificity within gerreid fishes and that geminate species within this parasite genus may have originated with the formation of the Isthmus of Panama (3.1 to 3.5 ma). Evidence is also presented suggesting the potential role of the Panama Canal as a passageway allowing the interoceanic dispersal of Aristocleidus species across the isthmus.

  19. Field-controllable Spin-Hall Effect of Light in Optical Crystals: A Conoscopic Mueller Matrix Analysis.

    Science.gov (United States)

    Samlan, C T; Viswanathan, Nirmal K

    2018-01-31

    Electric-field applied perpendicular to the direction of propagation of paraxial beam through an optical crystal dynamically modifies the spin-orbit interaction (SOI), leading to the demonstration of controllable spin-Hall effect of light (SHEL). The electro- and piezo-optic effects of the crystal modifies the radially symmetric spatial variation in the fast-axis orientation of the crystal, resulting in a complex pattern with different topologies due to the symmetry-breaking effect of the applied field. This introduces spatially-varying Pancharatnam-Berry type geometric phase on to the paraxial beam of light, leading to the observation of SHEL in addition to the spin-to-vortex conversion. A wave-vector resolved conoscopic Mueller matrix measurement and analysis provides a first glimpse of the SHEL in the biaxial crystal, identified via the appearance of weak circular birefringence. The emergence of field-controllable fast-axis orientation of the crystal and the resulting SHEL provides a new degree of freedom for affecting and controlling the spin and orbital angular momentum of photons to unravel the rich underlying physics of optical crystals and aid in the development of active photonic spin-Hall devices.

  20. [Deeper understanding of fetal acid-base equilibrium].

    Science.gov (United States)

    Roemer, V M

    1993-01-01

    variables of the fetal acid-base-balance is demonstrated in 738 newborns sharing Apgar-scores of 8 after one minute. The diagnostic potential of acid-base-variables in UV-blood as a mirror of placental function is outlined.

  1. Acid-base transport in pancreas – new challenges

    Directory of Open Access Journals (Sweden)

    Ivana eNovak

    2013-12-01

    Full Text Available Along the gastrointestinal tract a number of epithelia contribute with acid or basic secretions in order to aid digestive processes. The stomach and pancreas are the most extreme examples of acid (H+ and base (HCO3- transporters, respectively. Nevertheless, they share the same challenges of transporting acid and bases across epithelia and effectively regulating their intracellular pH. In this review, we will make use of comparative physiology to enlighten the cellular mechanisms of pancreatic HCO3- and fluid secretion, which is still challenging physiologists. Some of the novel transporters to consider in pancreas are the proton pumps (H+-K+-ATPases, as well as the calcium-activated K+ and Cl- channels, such as KCa3.1 and TMEM16A/ANO1. Local regulators, such as purinergic signalling, fine-tune and coordinate pancreatic secretion. Lastly, we speculate whether dys-regulation of acid-base transport contributes to pancreatic diseases including cystic fibrosis, pancreatitis and cancer.

  2. Acid/base titrations of simulated PWR crevice environments

    International Nuclear Information System (INIS)

    Pang, J.; Macdonald, D.D.; Millett, P.J.

    1993-01-01

    The construction and operation of a titration system that is capable of exploring the acid/base properties of aqueous systems at temperatures solution is measured using YSZ sensors of the type Hg/HgO/ZrO 2 (Y 2 O 3 )/Solution in conjunction with a suitable reference electrode. The use of the system for measuring the pH of the titrated solutions (NaOH/H 2 SO 4 ) is discussed, and we show that the YSZ pH sensor is capable of consistent and precise pH measurements at elevated temperature (275-325 degrees C) and pressures (100-150 bars). However, the accuracy of the measured pH depends critically on the performance of the reference electrode. In the present work, we ensure the viability of the reference electrode. In the present work, we ensure the viability of the reference electrode by periodically calibrating it in situ using the pH sensor and a standard solution of known pH versus temperature characteristics. The titration data obtained in this study are compared with predictions from EPRI's MULTEQ code, and are found to be in satisfactory agreement in the alkaline pH region. Observed discrepancies in the acidic pH region between the two sets of data are attributed to corrosion of the alloys used to fabricate the titration system

  3. Modeling the Acid-Base Properties of Montmorillonite Edge Surfaces.

    Science.gov (United States)

    Tournassat, Christophe; Davis, James A; Chiaberge, Christophe; Grangeon, Sylvain; Bourg, Ian C

    2016-12-20

    The surface reactivity of clay minerals remains challenging to characterize because of a duality of adsorption surfaces and mechanisms that does not exist in the case of simple oxide surfaces: edge surfaces of clay minerals have a variable proton surface charge arising from hydroxyl functional groups, whereas basal surfaces have a permanent negative charge arising from isomorphic substitutions. Hence, the relationship between surface charge and surface potential on edge surfaces cannot be described using the Gouy-Chapman relation, because of a spillover of negative electrostatic potential from the basal surface onto the edge surface. While surface complexation models can be modified to account for these features, a predictive fit of experimental data was not possible until recently, because of uncertainty regarding the densities and intrinsic pK a values of edge functional groups. Here, we reexamine this problem in light of new knowledge on intrinsic pK a values obtained over the past decade using ab initio molecular dynamics simulations, and we propose a new formalism to describe edge functional groups. Our simulation results yield reasonable predictions of the best available experimental acid-base titration data.

  4. The Acid-Base balance history (Part I

    Directory of Open Access Journals (Sweden)

    Mario Tarantino

    2007-08-01

    Full Text Available In the History of Medicine, the Acid-Base balance is unusual in that it has undergone constant evolution, not merely and not so much as a result of the progress of knowledge in physiological and physiopathological and clinical fields - which is common to all fields of Medical Science, but rather in relation to its very biochemical foundations, as was demonstrated by P. Stewart’s recent critical review and the reviews of J. Corey and J.A. Kellum, which are still valid today - and this is rather unusual. Although it started centuries ago, the history of the acidbase balance has experienced a slow and difficult evolution, and modern concepts almost exploded a couple of decades into the 20th century. It is therefore with even greater wonder and admiration that we look back on the pioneering intuitions of scholars such as R. Boyle, J.B. van Helmont and A.L. Lavoisier, to mention but a few of the scientists who laid the foundations for current knowledge in this fascinating chapter of physiology and clinical practice that belongs transversally to all medical and clinical disciplines.

  5. Water-wire catalysis in photoinduced acid-base reactions.

    Science.gov (United States)

    Kwon, Oh-Hoon; Mohammed, Omar F

    2012-07-07

    The pronounced ability of water to form a hyperdense hydrogen (H)-bond network among itself is at the heart of its exceptional properties. Due to the unique H-bonding capability and amphoteric nature, water is not only a passive medium, but also behaves as an active participant in many chemical and biological reactions. Here, we reveal the catalytic role of a short water wire, composed of two (or three) water molecules, in model aqueous acid-base reactions synthesizing 7-hydroxyquinoline derivatives. Utilizing femtosecond-resolved fluorescence spectroscopy, we tracked the trajectories of excited-state proton transfer and discovered that proton hopping along the water wire accomplishes the reaction more efficiently compared to the transfer occurring with bulk water clusters. Our finding suggests that the directionality of the proton movements along the charge-gradient H-bond network may be a key element for long-distance proton translocation in biological systems, as the H-bond networks wiring acidic and basic sites distal to each other can provide a shortcut for a proton in searching a global minimum on a complex energy landscape to its destination.

  6. Kinetics of acid base catalyzed transesterification of Jatropha curcas oil.

    Science.gov (United States)

    Jain, Siddharth; Sharma, M P

    2010-10-01

    Out of various non-edible oil resources, Jatropha curcas oil (JCO) is considered as future feedstock for biodiesel production in India. Limited work is reported on the kinetics of transesterification of high free fatty acids containing oil. The present study reports the results of kinetic study of two-step acid base catalyzed transesterification process carried out at an optimum temperature of 65 °C and 50 °C for esterification and transesterification respectively under the optimum methanol to oil ratio of 3:7 (v/v), catalyst concentration 1% (w/w) for H₂SO₄ and NaOH. The yield of methyl ester (ME) has been used to study the effect of different parameters. The results indicate that both esterification and transesterification reaction are of first order with reaction rate constant of 0.0031 min⁻¹ and 0.008 min⁻¹ respectively. The maximum yield of 21.2% of ME during esterification and 90.1% from transesterification of pretreated JCO has been obtained. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. A method for calculating the acid-base equilibria in aqueous and nonaqueous electrolyte solutions

    Science.gov (United States)

    Tanganov, B. B.; Alekseeva, I. A.

    2017-06-01

    Concentrations of particles in acid-base equilibria in aqueous and nonaqueous solutions of electrolytes are calculated on the basis of logarithmic charts, activity coefficients, and equilibrium constants.

  8. Acid-base thermochemistry of gaseous aliphatic α-aminoacids.

    Science.gov (United States)

    Bouchoux, Guy; Huang, Sihua; Inda, Bhawani Singh

    2011-01-14

    Acid-base thermochemistry of isolated aliphatic amino acids (denoted AAA): glycine, alanine, valine, leucine, isoleucine and proline has been examined theoretically by quantum chemical computations at the G3MP2B3 level. Conformational analysis on neutral, protonated and deprotonated species has been used to identify the lowest energy conformers and to estimate the population of conformers expected to be present at thermal equilibrium at 298 K. Comparison of the G3MP2B3 theoretical proton affinities, PA, and ΔH(acid) with experimental results is shown to be correct if experimental thermochemistry is re-evaluated and adapted to the most recent acidity-basicity scales. From this point of view, a set of evaluated proton affinities of 887, 902, 915, 916, 919 and 941 kJ mol(-1), and a set of evaluated ΔH(acid) of 1433, 1430, 1423, 1423, 1422 and 1426 kJ mol(-1), is proposed for glycine, alanine, valine, leucine, isoleucine and proline, respectively. Correlations with structural parameters (Taft's σ(α) polarizability parameter and molecular size) suggest that polarizability of the side chain is the major origin of the increase in PA and decrease in ΔH(acid) along the homologous series glycine, alanine, valine and leucine/isoleucine. Heats of formation of gaseous species AAA, AAAH(+) and [AAA-H](-) were computed at the G3MP2B3 level. The present study provides previously unavailable Δ(f)H°(298) for the ionized species AAAH(+) and [AAA-H](-). Comparison with Benson's estimate, and correlation with molecular size, show that several experimental Δ(f)H°(298) values of neutral or gaseous AAA might be erroneous.

  9. Redox and acid-base coupling in ultrathin polyelectrolyte films.

    Science.gov (United States)

    Tagliazucchi, Mario; Calvo, Ernesto J; Szleifer, Igal

    2008-03-18

    A single layer of poly(allylamine) with a covalently attached osmium pyridine-bipyridine complex adsorbed onto a Au surface modified by mercaptopropanesulfonate has been studied theoretically with a molecular approach and experimentally by cyclic voltammetry. These investigations have been carried out at different pHs and ionic strengths of the electrolyte solution in contact with the redox polyelectrolyte modified electrode. The theory predicts strong coupling between the acid-base and redox equilibria, particularly for low ionic strength, pH close to the pKa, and high concentration of redox sites. The coupling leads to a decrease in the peak potential at pH values above the apparent pKa of the weak polyelectrolyte, in good agreement with the experimental pH dependence at 4 mM NaNO3. Theoretical calculations suggest that the inflection point in the peak position versus pH curves can be used to estimate the apparent pKa of the amino groups in the polymer. Comparison of the apparent pKa for PAH-Os in the film with that of poly(allylamine) reported in the literature shows that the underlying charged thiol strongly influences charge regulation in the film. A systematic study of the film thickness and the degree of protonation in sulfonate and amino groups for solutions of different pH and ionic strength shows the coupling between the different interactions. It is found that the variation of the film properties has a non-monotonic dependence on bulk pH and salt concentration. For example, the film thickness shows a maximum with electrolyte ionic strength, whose origin is attributed to the balance between electrostatic amino-amino repulsions and amino-sulfonate attractions.

  10. Pathophysiological aspect of metabolic acid-base disorders

    Directory of Open Access Journals (Sweden)

    Nešović-Ostojić Jelena

    2016-01-01

    Full Text Available Maintaing the arterial pH values (in normal range of 7,35-7,45 is one of the main principles of homeostasis. Regulatory responses, including chemical buffering (extracellular, intracellular, sceletal, the regulation of pCO2 by the respiratory system, and the regulation of [HCO3-] by the kidneys, act in concert to maintain normal arterial pH value. The main extracellular chemical buffer is bicarbonate-carbonic acid buffer system. The kidneys contribute to the regulation of hydrogen (and bicarbonate in body fluids in two ways. Proximal tubules are important in bicarbonate reabsorption and distal tubules excrete hydrogen ion (as ammonium ion or titratable acid. There are four simple acid-base disorders: metabolic acidosis and metabolic alkalosis; respiratory acidosis and respiratory alkalosis. Metabolic acidosis can occur because of an increase in endogenous acid production (such as lactate and ketoacids, loss of bicarbonate (as in diarrhea, or accumulation of endogenous acids (as in renal failure. Metabolic acidosis can also be with high and normal (hyperchloremic metabolic acidosis anion gap. Renal tubular acidosis (RTA is a form of hyperchloremic metabolic acidosis which occurs when the renal damage primarily affects tubular function. The main problem in distal RTA is reduced H+ excretion in distal tubule. Type 2 RTA is also called proximal RTA because the main problem is greatly impaired reabsorption of bicarbonate in proximal tubule. Impaired cation exchange in distal tubule is the main problem in RTA type 4. Metabolic alkalosis occurs as a result of net gain of [HCO3-] or loss of nonvolatile acid from extracellular fluids. Metabolic alkalosis can be associated with reduced or increased extracellular volume.

  11. Mixed acid-base disorder secondary to topiramate use in traumatic brain injury

    Directory of Open Access Journals (Sweden)

    S Golla

    2016-01-01

    Full Text Available We report a case of a man with traumatic brain injury. He was started on to prophylactic topiramate which led to a mixed acid-base disorder. He had severe metabolic acidosis secondary to renal tubular acidification defect and respiratory alkalosis secondary to hyperventilation. Withdrawal of the offending drug led to the prompt resolution of the acid-base disturbance.

  12. Diet-induced modification of the acid-base balance in rats: toxicological implications

    NARCIS (Netherlands)

    Lina, Berend Adriaan Rene

    2004-01-01

    The composition of the diet can strongly affect the acid-base balance of the body. The studies described in this thesis deal with toxicological implications of dietary modulation of the acid-base balance in rats. These studies included 4-wk, 13-wk and 18-month toxicity studies, and a 30-month

  13. Using the Logarithmic Concentration Diagram, Log "C", to Teach Acid-Base Equilibrium

    Science.gov (United States)

    Kovac, Jeffrey

    2012-01-01

    Acid-base equilibrium is one of the most important and most challenging topics in a typical general chemistry course. This article introduces an alternative to the algebraic approach generally used in textbooks, the graphical log "C" method. Log "C" diagrams provide conceptual insight into the behavior of aqueous acid-base systems and allow…

  14. The acid-base resistant zone in three dentin bonding systems.

    Science.gov (United States)

    Inoue, Go; Nikaido, Toru; Foxton, Richard M; Tagami, Junji

    2009-11-01

    An acid-base resistant zone has been found to exist after acid-base challenge adjacent to the hybrid layer using SEM. The aim of this study was to examine the acid-base resistant zone using three different bonding systems. Dentin disks were applied with three different bonding systems, and then a resin composite was light-cured to make dentin disk sandwiches. After acid-base challenge, the polished surfaces were observed using SEM. For both one- and two-step self-etching primer systems, an acid-base resistant zone was clearly observed adjacent to the hybrid layer - but with differing appearances. For the wet bonding system, the presence of an acid-base resistant zone was unclear. This was because the self-etching primer systems etched the dentin surface mildly, such that the remaining mineral phase of dentin and the bonding agent yielded clear acid-base resistant zones. In conclusion, the acid-base resistant zone was clearly observed when self-etching primer systems were used, but not so for the wet bonding system.

  15. A Comparative Study of French and Turkish Students' Ideas on Acid-Base Reactions

    Science.gov (United States)

    Cokelez, Aytekin

    2010-01-01

    The goal of this comparative study was to determine the knowledge that French and Turkish upper secondary-school students (grades 11 and 12) acquire on the concept of acid-base reactions. Following an examination of the relevant curricula and textbooks in the two countries, 528 students answered six written questions about the acid-base concept.…

  16. Collaborative Strategies for Teaching Common Acid-Base Disorders to Medical Students

    Science.gov (United States)

    Petersen, Marie Warrer; Toksvang, Linea Natalie; Plovsing, Ronni R.; Berg, Ronan M. G.

    2014-01-01

    The ability to recognize and diagnose acid-base disorders is of the utmost importance in the clinical setting. However, it has been the experience of the authors that medical students often have difficulties learning the basic principles of acid-base physiology in the respiratory physiology curriculum, particularly when applying this knowledge to…

  17. High School Students' Understanding of Acid-Base Concepts: An Ongoing Challenge for Teachers

    Science.gov (United States)

    Damanhuri, Muhd Ibrahim Muhamad; Treagust, David F.; Won, Mihye; Chandrasegaran, A. L.

    2016-01-01

    Using a quantitative case study design, the "Acids-Bases Chemistry Achievement Test" ("ABCAT") was developed to evaluate the extent to which students in Malaysian secondary schools achieved the intended curriculum on acid-base concepts. Responses were obtained from 260 Form 5 (Grade 11) students from five schools to initially…

  18. Canonical Pedagogical Content Knowledge by Cores for Teaching Acid-Base Chemistry at High School

    Science.gov (United States)

    Alvarado, Clara; Cañada, Florentina; Garritz, Andoni; Mellado, Vicente

    2015-01-01

    The topic of acid-base chemistry is one of the oldest in general chemistry courses and it has been almost continuously in academic discussion. The central purpose of documenting the knowledge and beliefs of a group of ten Mexican teachers with experience in teaching acid-base chemistry in high school was to know how they design, prepare and…

  19. Thai Grade 11 Students' Alternative Conceptions for Acid-Base Chemistry

    Science.gov (United States)

    Artdej, Romklao; Ratanaroutai, Thasaneeya; Coll, Richard Kevin; Thongpanchang, Tienthong

    2010-01-01

    This study involved the development of a two-tier diagnostic instrument to assess Thai high school students' understanding of acid-base chemistry. The acid-base diagnostic test (ABDT) comprising 18 items was administered to 55 Grade 11 students in a science and mathematics programme during the second semester of the 2008 academic year. Analysis of…

  20. Development of a measurement device, using a Geiger-Mueller type detector, for the determination of the activity in a 99mTc generator prototype

    International Nuclear Information System (INIS)

    Urquizo, Rafael; Gago, Javier; Mendoza, Pablo; Cruz-Saco, Cesar; Rojas, Jorge

    2014-01-01

    This article presents the implementation of a measurement system using a Geiger-Mueller detector (GM) in order to adapt it into a 99m Tc generator prototype. The response signal of the measurement system designed in terms of count rate is linearly proportional to the variation of the activity measured between 280 and 170 mCi of 99m Tc with a relative error of ± 2,8 %. However, further tests are needed to evaluate the correlation for an activity level lower than 20 mCi in order to obtain an adequate range of use. (authors).

  1. Nomina nova in Platyhelminthes pro Macrorhynchus von Graff, 1882 (non [Gmelin, 1801]; non Dunker, 1843), and Leptocleidus Mueller, 1936 (non Andrews, 1922).

    Science.gov (United States)

    Hornung, Jahn J

    2016-08-19

    Two genus-group names of flat-worms-Leptocleidus Mueller, 1936 and Macrorhynchus von Graff, 1882-are junior homonyms that are preoccupied by fossil diapsid reptile genera-Leptocleidus Andrews, 1922, and Macrorhynchus Dunker, 1843-and an extant teleost fish genus-Macrorhynchus [Gmelin, 1801] ex La Cépède, 1800. These are replaced by nomina nova (Pharyngodytes nom. nov.; Graffiellus nom. nov.). Macrorhynchus [Gmelin, 1801] is an objective senior synonym of Macrorhyncus Dumeríl, 1805 ex La Cépède, 1800 (syn. nov.), and a senior homonym of Macrorhynchus Dunker, 1843, and Macrorhynchus von Graff, 1882.

  2. Comparative study on the anticancer activities and binding properties of a hetero metal binuclear complex [Co(dipic)2Ni(OH2)5]·2H2O (dipic=dipicolinate) with two carrier proteins.

    Science.gov (United States)

    Shahraki, Somaye; Shiri, Fereshteh; Majd, Mostafa Heidari; Razmara, Zohreh

    2017-10-25

    Recognizing of binding mechanisms between drugs and carrier proteins is basic for us to understand the pharmacokinetics and pharmacodynamics of them. In this research, the anticancer activities of a binuclear complex [Co(dipic) 2 Ni(OH 2 ) 5 ]·2H 2 O (dipic=dipicolinate) against MDA-MB-231 cell lines were studied. Results of MTT assay and flow cytometry analysis revealed that above complex can induce the cytotoxicity and the apoptosis in breast cancer cell lines. So, this complex was selected to investigate its binding to human serum albumin (HSA) and bovine β-lactoglobulin (βLG) by spectroscopic methods (UV-visible, fluorescence and FT-IR) along with molecular docking technique. The fluorescence data showed Co-Ni complex quench the fluorescence of both proteins by a static quenching mechanism and HSA has stronger binding affinity toward Co-Ni complex than βLG. The binding constant (K b ), number of binding sites (n) and thermodynamic parameters were calculated and showed that the Co-Ni complex binds to protein (HSA and βLG) through hydrogen bonding and van der Waals forces with one binding site. The results of UV-visible measurements indicated that the binding of above complex to HSA and βLG may induce conformational and micro-environmental changes of studied proteins. Protein-ligand docking analysis confirmed that the Co-Ni complex binds to residues located in the subdomain IIA of HSA and site II of βLG. Copyright © 2017. Published by Elsevier B.V.

  3. Metabolic Effects of a Succinic Acid Substrate Antihypoxant

    Directory of Open Access Journals (Sweden)

    B. N. Shakh

    2014-01-01

    Full Text Available The paper discusses promises for clinical use of substrate antihypoxants.Objective: to investigate the efficacy of succinate containing  substrate  antihypoxants  on  systemic  oxygen  consumption,  blood  buffer  capacity,  and  changes  in  the  mixed venous blood level of lactate when they are used in gravely sick patients and victims with marked metabolic posthypoxic disorders.Subjects and methods. The trial enrolled 30 patients and victims who had sustained an episode of severe hypoxia of mixed genesis, the severity of which was evaluated by the APACHE II scale and amounted to 23 to 30 scores with a 46 to 70.3% risk of death. The standard infusion program in this group involved the succinate-containing drug 1.5% reamberin solution  in  a  total  dose  of  800  ml.  A  comparison  group  included  15  patients  who  had  undergone  emergency  extensive surgery for abdominal diseases. 400 ml of 10% glucose solution was used as an infusion medium. Oxygen consumption (VO2ml/min and carbon dioxide production (VCO2ml/min were measured before infusion and monitored for 2 hours. Arterial blood gases and acid-base balance (ABB parameters and mixed venous blood lactate levels were examined. Measurements were made before and 30 minutes after the infusion of reamberin or glucose solution.Results. Infusion of 1.5% reamberin solution was followed by a significant increase in minute oxygen consumption from 281.5±21.2 to 310.4±24.4 ml/min. CO2 production declined (on average, from 223.3±6.5 to 206.5±7.59 ml/min. During infusion of 10% glucose solution, all the patients of the comparison group showed a rise in oxygen consumption from 303.6±33.86 to 443.13±32.1 ml/min, i.e. about 1.5-fold. VCO2 changed similarly. The intravenous infusion of 800 ml of 1.5% reamberin solution raised arterial blood buffer capacity, which was reflected by changes in pH, BE, and HCO3. There was a clear trend for lactate values to drop in the

  4. Structure and functioning of the acid-base system in the Baltic Sea

    Science.gov (United States)

    Kuliński, Karol; Schneider, Bernd; Szymczycha, Beata; Stokowski, Marcin

    2017-12-01

    The marine acid-base system is relatively well understood for oceanic waters. Its structure and functioning is less obvious for the coastal and shelf seas due to a number of regionally specific anomalies. In this review article we collect and integrate existing knowledge of the acid-base system in the Baltic Sea. Hydrographical and biogeochemical characteristics of the Baltic Sea, as manifested in horizontal and vertical salinity gradients, permanent stratification of the water column, eutrophication, high organic-matter concentrations and high anthropogenic pressure, make the acid-base system complex. In this study, we summarize the general knowledge of the marine acid-base system as well as describe the peculiarities identified and reported for the Baltic Sea specifically. In this context we discuss issues such as dissociation constants in brackish water, different chemical alkalinity models including contributions by organic acid-base systems, long-term changes in total alkalinity, anomalies of borate alkalinity, and the acid-base effects of biomass production and mineralization. Finally, we identify research gaps and specify limitations concerning the Baltic Sea acid-base system.

  5. Swelling-induced optical anisotropy of thermoresponsive hydrogels based on poly(2-(2-methoxyethoxy)ethyl methacrylate): deswelling kinetics probed by quantitative Mueller matrix polarimetry.

    Science.gov (United States)

    Patil, Nagaraj; Soni, Jalpa; Ghosh, Nirmalya; De, Priyadarsi

    2012-11-29

    Thermodynamically favored polymer-water interactions below the lower critical solution temperature (LCST) caused swelling-induced optical anisotropy (linear retardance) of thermoresponsive hydrogels based on poly(2-(2-methoxyethoxy)ethyl methacrylate). This was exploited to study the macroscopic deswelling kinetics quantitatively by a generalized polarimetry analysis method, based on measurement of the Mueller matrix and its subsequent inverse analysis via the polar decomposition approach. The derived medium polarization parameters, namely, linear retardance (δ), diattenuation (d), and depolarization coefficient (Δ), of the hydrogels showed interesting differences between the gels prepared by conventional free radical polymerization (FRP) and reversible addition-fragmentation chain transfer polymerization (RAFT) and also between dry and swollen state. The effect of temperature, cross-linking density, and polymerization technique employed to synthesize hydrogel on deswelling kinetics was systematically studied via conventional gravimetry and corroborated further with the corresponding Mueller matrix derived quantitative polarimetry characteristics (δ, d, and Δ). The RAFT gels exhibited higher swelling ratio and swelling-induced optical anisotropy compared to FRP gels and also deswelled faster at 30 °C. On the contrary, at 45 °C, deswelling was significantly retarded for the RAFT gels due to formation of a skin layer, which was confirmed and quantified via the enhanced diattenuation and depolarization parameters.

  6. Acid-Base and Electrolyte Disorders in Patients with and without Chronic Kidney Disease: An Update.

    Science.gov (United States)

    Dhondup, Tsering; Qian, Qi

    2017-12-01

    Kidneys play a pivotal role in the maintenance and regulation of acid-base and electrolyte homeostasis, which is the prerequisite for numerous metabolic processes and organ functions in the human body. Chronic kidney diseases compromise the regulatory functions, resulting in alterations in electrolyte and acid-base balance that can be life-threatening. In this review, we discuss the renal regulations of electrolyte and acid-base balance and several common disorders including metabolic acidosis, alkalosis, dysnatremia, dyskalemia, and dysmagnesemia. Common disorders in chronic kidney disease are also discussed. The most recent and relevant advances on pathophysiology, clinical characteristics, diagnosis, and management of these conditions have been incorporated.

  7. A REVIEW ON ACID BASE STATUS IN DAIRY COWS: IMPLICATIONS OF DIETARY CATION-ANION BALANCE

    Directory of Open Access Journals (Sweden)

    D. Afzaal, M. Nisa, M. A. Khan and M. Sarwar

    2004-10-01

    Full Text Available The acid base status of a dairy cow is maintained within a narrow range. The key mechanisms involving blood, cells and lungs, perform this function. Although other minerals have an impact on acid base metabolism, the minerals used in dietary cation-anion balance (DCAB namely sodium (Na, potassium (K and chloride (Cl have the greatest effect. Hence, acid base status implicates other biological functions of dairy cows. Low DCAB prepartum reduces the incidence of milk fever and increases the productivity by simmering down the severity of hypocalcaemia. High DCAB diets have proved to increase dry mater and water intake and production and to mitigate the effects of heat stress.

  8. Acid-base equilibrium. A thermodynamic study of formation and stability of the Bi-2223 phase

    International Nuclear Information System (INIS)

    Xi, Z.; Zhou, L.

    1993-01-01

    A general acid-base equilibrium theory was proposed to explain the formation and stability of the Bi-2223 phase based on the Lewis acid base theory and principle of metallurgical physical chemistry. The acid-base nature of oxide was defined according to the electrostatic force between cation and oxygen anion. A series of experimental facts were systematically explained based on the theory: substitution of Bi for Ca in the Pb-free 2223 phase, and the effect of substitution of the high-valent cation for Bi 3+ ; oxygen-pressure atmosphere, and the heat-schocking technique on the formation and stability of the 2223 phase. 14 refs., 2 tabs

  9. High Performance Fatty Acid-Based Vinyl Ester Resin for Liquid Molding

    National Research Council Canada - National Science Library

    Geng, Xing; La Scala, John J; Sands, James M; Palmese, Guiseppe R

    2007-01-01

    ...% compared to 40-60 wt% associated with commercial products. In addition, fatty acid-based monomers can bring about other benefits like higher toughness, lower exothermal heat and low volume shrinkage...

  10. Efficacy of pretreating oil palm fronds with an acid-base mixture catalyst.

    Science.gov (United States)

    Jung, Young Hoon; Park, Hyun Min; Park, Yong-Cheol; Park, Kyungmoon; Kim, Kyoung Heon

    2017-07-01

    Oil palm fronds are abundant but recalcitrant to chemical pretreatment. Herein, an acid-base mixture was applied as a catalyst to efficiently pretreat oil palm fronds. Optimized conditions for the pretreatment were a 0.1M acidic acid-base mixture and 3min ramping to 190°C and 12min holding. The oil palm fronds pretreated and washed with the acid-base mixture exhibited an enzymatic digestibility of 85% by 15 FPU Accellerase 1000/g glucan after 72h hydrolysis, which was significantly higher than the enzymatic digestibilities obtained by acid or alkali pretreatment alone. This could be attributed to the synergistic actions of the acid and base, producing an 87% glucose recovery with 100% and 40.3% removal of xylan and lignin, respectively, from the solids. Therefore, an acid-base mixture can be a feasible catalyst to deconstruct oil palm fronds for sugar production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Going Beyond, Going Further: The Preparation of Acid-Base Titration Curves.

    Science.gov (United States)

    McClendon, Michael

    1984-01-01

    Background information, list of materials needed, and procedures used are provided for a simple technique for generating mechanically plotted acid-base titration curves. The method is suitable for second-year high school chemistry students. (JN)

  12. Why and How To Teach Acid-Base Reactions without Equilibrium.

    Science.gov (United States)

    Carlton, Terry S.

    1997-01-01

    Recommends an approach to the treatment of acid-base equilibria that involves treating each reaction as either going to completion or not occurring at all. Compares the method with the traditional approach step by step. (DDR)

  13. Complexity in Acid?Base Titrations: Multimer Formation Between Phosphoric Acids and Imines

    OpenAIRE

    Malm, Christian; Kim, Heejae; Wagner, Manfred; Hunger, Johannes

    2017-01-01

    Abstract Solutions of Br?nsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Br?nsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid?base aggregates challenging. Here, we track such acid?base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by u...

  14. A Clinical Approach to the Diagnosis of Acid-Base Disorders

    OpenAIRE

    Bear, Robert A.

    1986-01-01

    The ability to diagnose and manage acid-base disorders rapidly and effectively is essential to the care of critically ill patients. This article presents an approach to the diagnosis of pure and mixed acid-base disorders, metabolic or respiratory. The approach taken is based on using the law of mass-action equation as it applies to the bicarbonate buffer system (Henderson equation), using sub-classifications for diagnostic purposes of causes of metabolic acidosis and metabolic alkalosis, and ...

  15. Quantitative acid-base physiology using the Stewart model. Does it improve our understanding of what is really wrong?

    NARCIS (Netherlands)

    Derksen, R.; Scheffer, G.J.; Hoeven, J.G. van der

    2006-01-01

    Traditional theories of acid-base balance are based on the Henderson-Hasselbalch equation to calculate proton concentration. The recent revival of quantitative acid-base physiology using the Stewart model has increased our understanding of complicated acid-base disorders, but has also led to several

  16. Electrolyte and Acid-Base Disturbances in End-Stage Liver Disease: A Physiopathological Approach.

    Science.gov (United States)

    Jiménez, José Víctor; Carrillo-Pérez, Diego Luis; Rosado-Canto, Rodrigo; García-Juárez, Ignacio; Torre, Aldo; Kershenobich, David; Carrillo-Maravilla, Eduardo

    2017-08-01

    Electrolyte and acid-base disturbances are frequent in patients with end-stage liver disease; the underlying physiopathological mechanisms are often complex and represent a diagnostic and therapeutic challenge to the physician. Usually, these disorders do not develop in compensated cirrhotic patients, but with the onset of the classic complications of cirrhosis such as ascites, renal failure, spontaneous bacterial peritonitis and variceal bleeding, multiple electrolyte, and acid-base disturbances emerge. Hyponatremia parallels ascites formation and is a well-known trigger of hepatic encephalopathy; its management in this particular population poses a risky challenge due to the high susceptibility of cirrhotic patients to osmotic demyelination. Hypokalemia is common in the setting of cirrhosis: multiple potassium wasting mechanisms both inherent to the disease and resulting from its management make these patients particularly susceptible to potassium depletion even in the setting of normokalemia. Acid-base disturbances range from classical respiratory alkalosis to high anion gap metabolic acidosis, almost comprising the full acid-base spectrum. Because most electrolyte and acid-base disturbances are managed in terms of their underlying trigger factors, a systematic physiopathological approach to their diagnosis and treatment is required.

  17. Complexity in Acid-Base Titrations: Multimer Formation Between Phosphoric Acids and Imines.

    Science.gov (United States)

    Malm, Christian; Kim, Heejae; Wagner, Manfred; Hunger, Johannes

    2017-08-10

    Solutions of Brønsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Brønsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid-base aggregates challenging. Here, we track such acid-base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by using a combination of dielectric relaxation and NMR spectroscopy. In contrast to what one would expect for an acid-base titration, we find strong deviations from quantitative proton transfer from the acid to the base. Even for an excess of the base, multimers consisting of one base and at least two acid molecules are formed, in addition to the occurrence of proton transfer from the acid to the base and simultaneous formation of ion pairs. For equimolar mixtures such multimers constitute about one third of all intermolecular aggregates. Quantitative analysis of our results shows that the acid-base association constant is only around six times larger than that for the acid binding to an acid-base dimer, that is, to an already protonated base. Our findings have implications for the interpretation of previous studies of reactive intermediates in organocatalysis and provide a rationale for previously observed nonlinear effects in phosphoric acid catalysis. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  18. Traditional and quantitative assessment of acid-base and shock variables in horses with atypical myopathy.

    Science.gov (United States)

    van Galen, G; Cerri, S; Porter, S; Saegerman, C; Lefere, L; Roscher, K; Marr, C; Amory, H; Votion, D M

    2013-01-01

    Descriptions of acid-base disturbances in atypical myopathy (AM) are limited. Describe and compare traditional and quantitative acid-base abnormalities and cardiovascular shock status in horses with AM at admission. 34 horses with AM, 15 healthy controls. Retrospective case-control study. Records were searched for shock variables (packed cell volume [PCV], blood urea nitrogen [BUN], heart and respiratory rate) and acid-base variables (venous blood gas analysis, electrolytes, total protein, lactate) on admission. Base excess (BE) of free water (BEfw), chloride (BEcl), total protein (BEtp), and unidentified anions (BEua), anion gap (AG), measured strong ion difference (SIDm), and concentration of total nonvolatile weak acids ([Atot]) were calculated. Acid-base classifications, using simplified strong ion model and traditional approach, and shock grades were assigned. A 2-sample Wilcoxon rank-sum test and Bonferroni correction compared variables in AM cases versus control horses. Significance was P horses. The strong ion model provided a more accurate assessment than the traditional approach and identified mixed derangements. Acid-base derangements should be evaluated in horses with AM and this preferably with the strong ion model. Copyright © 2012 by the American College of Veterinary Internal Medicine.

  19. Potentiometric Measurement of Transition Ranges and Titration Errors for Acid/Base Indicators

    Science.gov (United States)

    Flowers, Paul A.

    1997-07-01

    Sophomore analytical chemistry courses typically devote a substantial amount of lecture time to acid/base equilibrium theory, and usually include at least one laboratory project employing potentiometric titrations. In an effort to provide students a laboratory experience that more directly supports their classroom discussions on this important topic, an experiment involving potentiometric measurement of transition ranges and titration errors for common acid/base indicators has been developed. The pH and visually-assessed color of a millimolar strong acid/base system are monitored as a function of added titrant volume, and the resultant data plotted to permit determination of the indicator's transition range and associated titration error. Student response is typically quite positive, and the measured quantities correlate reasonably well to literature values.

  20. Study of the acid-base properties of mineral soil horizons using pK spectroscopy

    Science.gov (United States)

    Shamrikova, E. V.; Vanchikova, E. V.; Ryazanov, M. A.

    2007-11-01

    The presence of groups 4 and 5 participating in acid-base equilibria was revealed in samples from mineral horizons of the gley-podzolic soil of the Komi Republic using pK spectroscopy (the mathematical processing of potentiometric titration curves for plotting the distribution of acid groups according to their pK values). The specific quantity of acid-base sites in soil samples was calculated. The contribution of organic and mineral soil components to the groups of acid-base sites was estimated. The pK values of groups determining the potential, exchangeable, and unexchangeable acidities were found. The heterogeneity of acid components determining different types of soil acidity was revealed.

  1. Effect of acute acid loading on acid-base and calcium metabolism

    DEFF Research Database (Denmark)

    Osther, Palle J

    2006-01-01

    OBJECTIVE: To investigate the acid-base and calcium metabolic responses to acute non-carbonic acid loading in idiopathic calcium stone-formers and healthy males using a quantitative organ physiological approach. MATERIAL AND METHODS: Five-h ammonium chloride loading studies were performed in 12...... male recurrent idiopathic calcium stone-formers and 12 matched healthy men using a randomized, placebo-controlled, cross-over design. Arterialized capillary blood, serum and urine were collected hourly for measurement of electrolytes, ionized calcium, magnesium, phosphate, parathyroid hormone and acid-base...... status. Concentrations of non-metabolizable base (NB) and acid (NA) were calculated from measured concentrations of non-metabolizable ions. RESULTS: The extracellular acid-base status in the stone-formers during basal conditions and acid loading was comparable to the levels in the healthy controls...

  2. Development of an polarization sensitive Fourier domain optical coherence tomography and it utilization on the Mueller matrix determination; Desenvolvimento de um sistema de tomografia por coerencia optica no dominio de Fourier sensivel a polarizacao e sua utilizacao na determinacao das matrizes de Mueller

    Energy Technology Data Exchange (ETDEWEB)

    Raele, Marcus Paulo

    2009-07-01

    This study approached theoretical and experimental aspects related with the development of a polarization sensitive, Fourier domain, optical coherence tomography system (PS-FD-OCT) and its utilization on the Mueller Matrix determination. This work began with a bibliographic revision, which describes since the early studies to the actual state of the art of the technique. The mathematical formalism of Fourier domain low coherence interferometry and light polarization was performed as well. Studies based on numerical simulations, of three different algorithm types, responsible to recover the scattering profile, were done. The implemented algorithms were: Direct Fourier Transform, Interpolation and zero-filling. By the end of the simulation study, was possible to conclude that the algorithm zero-filling 2N presented better characteristics when compared with the others. In the experimental part, firstly different OCT setups were assembled and measurements were done in order to verify aspects related with the theory. Then, using a polymeric sample, birefringence images were performed, which allowed determining the sample birefringence quantitatively. Finally, images taken of different polarization states were collected, and through then images related with the Mueller Matrix elements were calculated, which were analyzed individually. (author)

  3. Photochemistry of nucleic acid bases and their thio- and aza-analogues in solution.

    Science.gov (United States)

    Pollum, Marvin; Martínez-Fernández, Lara; Crespo-Hernández, Carlos E

    2015-01-01

    The steady-state and time-resolved photochemistry of the natural nucleic acid bases and their sulfur- and nitrogen-substituted analogues in solution is reviewed. Emphasis is given to the experimental studies performed over the last 3-5 years that showcase topical areas of scientific inquiry and those that require further scrutiny. Significant progress has been made toward mapping the radiative and nonradiative decay pathways of nucleic acid bases. There is a consensus that ultrafast internal conversion to the ground state is the primary relaxation pathway in the nucleic acid bases, whereas the mechanism of this relaxation and the level of participation of the (1)πσ*, (1) nπ*, and (3)ππ* states are still matters of debate. Although impressive research has been performed in recent years, the microscopic mechanism(s) by which the nucleic acid bases dissipate excess vibrational energy to their environment, and the role of the N-glycosidic group in this and in other nonradiative decay pathways, are still poorly understood. The simple replacement of a single atom in a nucleobase with a sulfur or nitrogen atom severely restricts access to the conical intersections responsible for the intrinsic internal conversion pathways to the ground state in the nucleic acid bases. It also enhances access to ultrafast and efficient inter-system crossing pathways that populate the triplet manifold in yields close to unity. Determining the coupled nuclear and electronic pathways responsible for the significantly different photochemistry in these nucleic acid base analogues serves as a convenient platform to examine the current state of knowledge regarding the photodynamic properties of the DNA and RNA bases from both experimental and computational perspectives. Further investigations should also aid in forecasting the prospective use of sulfur- and nitrogen-substituted base analogues in photochemotherapeutic applications.

  4. Mobile Clinical Decision Support System for Acid-base Balance Diagnosis and Treatment Recommendation.

    Science.gov (United States)

    Mandzuka, Mensur; Begic, Edin; Boskovic, Dusanka; Begic, Zijo; Masic, Izet

    2017-06-01

    This paper presents mobile application implementing a decision support system for acid-base disorder diagnosis and treatment recommendation. The application was developed using the official integrated development environment for the Android platform (to maximize availability and minimize investments in specialized hardware) called Android Studio. The application identifies disorder, based on the blood gas analysis, evaluates whether the disorder has been compensated, and based on additional input related to electrolyte imbalance, provides recommendations for treatment. The application is a tool in the hands of the user, which provides assistance during acid-base disorders treatment. The application will assist the physician in clinical practice and is focused on the treatment in intensive care.

  5. [Disorders of the acid-base balance and the anion gap].

    Science.gov (United States)

    Kimmel, Martin; Alscher, Mark Dominik

    2016-10-01

    The regulation of the acid-base balance and pH is critical for the organism. The most important buffer system is CO 2 / HCO 3 - . The kidney controls systemic bicarbonate and therefore the metabolic regulation and the lung is relevant for respiratory regulation by an effective CO 2 elimination. There are four acid-base disorders with two metabolic and two respiratory disorders (acidosis and alkalosis). The anion gap enables a further workup of metabolic acidosis. © Georg Thieme Verlag KG Stuttgart · New York.

  6. Essentials in the diagnosis of acid-base disorders and their high altitude application.

    Science.gov (United States)

    Paulev, P E; Zubieta-Calleja, G R

    2005-09-01

    This report describes the historical development in the clinical application of chemical variables for the interpretation of acid-base disturbances. The pH concept was already introduced in 1909. Following World War II, disagreements concerning the definition of acids and bases occurred, and since then two strategies have been competing. Danish scientists in 1923 defined an acid as a substance able to give off a proton at a given pH, and a base as a substance that could bind a proton, whereas the North American Singer-Hasting school in 1948 defined acids as strong non-buffer anions and bases as non-buffer cations. As a consequence of this last definition, electrolyte disturbances were mixed up with real acid-base disorders and the variable, strong ion difference (SID), was introduced as a measure of non-respiratory acid-base disturbances. However, the SID concept is only an empirical approximation. In contrast, the Astrup/Siggaard-Andersen school of scientists, using computer strategies and the Acid-base Chart, has made diagnosis of acid-base disorders possible at a glance on the Chart, when the data are considered in context with the clinical development. Siggaard-Andersen introduced Base Excess (BE) or Standard Base Excess (SBE) in the extracellular fluid volume (ECF), extended to include the red cell volume (eECF), as a measure of metabolic acid-base disturbances and recently replaced it by the term Concentration of Titratable Hydrogen Ion (ctH). These two concepts (SBE and ctH) represent the same concentration difference, but with opposite signs. Three charts modified from the Siggaard-Andersen Acid-Base Chart are presented for use at low, medium and high altitudes of 2500 m, 3500 m, and 4000 m, respectively. In this context, the authors suggest the use of Titratable Hydrogen Ion concentration Difference (THID) in the extended extracellular fluid volume, finding it efficient and better than any other determination of the metabolic component in acid-base

  7. Mutagenicity of irradiated solutions of nuclei acid bases and nucleosides in Salmonella typhimurium

    International Nuclear Information System (INIS)

    Wilmer, J.; Schubert, J.

    1981-01-01

    Solutions of nucleic acid bases, nucleosides and a nucleotide, saturated with either N 2 , N 2 O or O 2 , were irradiated and tested for mutagenicity towards Salmonella typhimurium, with and without pre-incubation. Irradiated solutions of the nuclei acid bases were all non-mutagenic. Irradiated solutions of the nucleosides showed mutagenicity in S. typhimurium TA100 (pre-incubation assay). Generally, the mutagenicity followed the order: N 2 O > N 2 > O 2 . The results show that the formation of mutagenic radiolytic products is initiated by attack of mainly solutions of the nucleotide thymidine-5'-monophosphate, no mutagenicity could be detected. (orig.)

  8. Effect of Intravenously Administered Crystalloid Solutions on Acid?Base Balance in Domestic Animals

    OpenAIRE

    Muir, W.

    2017-01-01

    Intravenous fluid therapy can alter plasma acid?base balance. The Stewart approach to acid?base balance is uniquely suited to identify and quantify the effects of the cationic and anionic constituents of crystalloid solutions on plasma pH. The plasma strong ion difference (SID) and weak acid concentrations are similar to those of the administered fluid, more so at higher administration rates and with larger volumes. A crystalloid's in vivo effects on plasma pH are described by 3 general rules...

  9. Acid-base regulation in tadpoles of Rana catesbeiana exposed to environmental hypercapnia

    DEFF Research Database (Denmark)

    Busk, Morten; Larsen, Erik Hviid; Jensen, Frank B.

    1997-01-01

    Tadpoles of Rana catesbeiana were exposed to different levels of environmental hypercapnia. The acid-base regulatory response differed from that in adult amphibians in showing a high degree of pH compensation in the extracellular fluid (65-85%) and complete compensation in the intracellular fluid......). It is suggested that the large bicarbonate efflux from the animal is a consequence of the dissolution of CaCO3 stores and the delayed adjustment of bicarbonate-retaining mechanisms. Re-exposure of tadpoles to hypercapnia after 1-3 weeks of normocapnic recovery only affected transepithelial fluxes of acid-base...

  10. The determination of acid-base properties of polymer surfaces by XPS: Present status and future prospects

    International Nuclear Information System (INIS)

    Chehimi, M.M.; Delamar, M.; Shahidzadeh-Ahmadi, N.; Arefi-Khonsari, F.; Amouroux, J.; Watts, J.F.

    1996-01-01

    The use of the molecular probe technique in conjunction with X-ray photoelectron spectroscopy (XPS) for the assessment of acid-base properties of polymer surfaces is reviewed. The method is based on the determination of the concentration and chemical shifts of Lewis acids (bases) sorbed in polymers of basic (acidic) character. In the case of chloroform (Lewis acid) sorbed in polymers of Lewis basic character, C12p binding energy is linearly correlated with ΔH AB , the heat of acid-base complex formation chloroform-polymer. This relationship has been used to determine the acid-base properties of poly(phenylene oxide), a homopolymer, and ammonia plasma-treated polypropylene. This work shows that XPS can now indeed be used to quantitatively assess the acid-base properties of modified polymer surfaces and perhaps be extended to map acid-base properties of polymer surfaces at the micron or submicron scale. copyright 1996 American Institute of Physics

  11. Intracellular pH regulation by acid-base transporters in mammalian neurons

    Science.gov (United States)

    Ruffin, Vernon A.; Salameh, Ahlam I.; Boron, Walter F.; Parker, Mark D.

    2014-01-01

    Intracellular pH (pHi) regulation in the brain is important in both physiological and physiopathological conditions because changes in pHi generally result in altered neuronal excitability. In this review, we will cover 4 major areas: (1) The effect of pHi on cellular processes in the brain, including channel activity and neuronal excitability. (2) pHi homeostasis and how it is determined by the balance between rates of acid loading (JL) and extrusion (JE). The balance between JE and JL determine steady-state pHi, as well as the ability of the cell to defend pHi in the face of extracellular acid-base disturbances (e.g., metabolic acidosis). (3) The properties and importance of members of the SLC4 and SLC9 families of acid-base transporters expressed in the brain that contribute to JL (namely the Cl-HCO3 exchanger AE3) and JE (the Na-H exchangers NHE1, NHE3, and NHE5 as well as the Na+- coupled HCO3− transporters NBCe1, NBCn1, NDCBE, and NBCn2). (4) The effect of acid-base disturbances on neuronal function and the roles of acid-base transporters in defending neuronal pHi under physiopathologic conditions. PMID:24592239

  12. The Effect of Voluntary Ventilation on Acid-base Responses to a Moo Duk Tkow Form.

    Science.gov (United States)

    Hetzler, Ronald K.; And Others

    1989-01-01

    Results are reported from a study that investigated the acid-base and lactate reponses to voluntary integration of breathing and exercise movements during beginning level form Ki Cho I, performed at competitive intensities. Findings suggest that respiratory compensation does not occur and that respiratory acidosis may contribute to metabolic…

  13. Analysis and Identification of Acid-Base Indicator Dyes by Thin-Layer Chromatography

    Science.gov (United States)

    Clark, Daniel D.

    2007-01-01

    Thin-layer chromatography (TLC) is a very simple and effective technique that is used by chemists by different purposes, including the monitoring of the progress of a reaction. TLC can also be easily used for the analysis and identification of various acid-base indicator dyes.

  14. General treatment of conjugate acid-base, redox and complexation equilibria.

    Science.gov (United States)

    Elenkova, N G

    1980-09-01

    Acid-base, redox and complexation reactions are treated uniformly in terms of particle transfer. As a result, a single set of mathematical equations can be used to describe all three types of reaction and to perform the usual calculations for these systems.

  15. Effect of acute metabolic acid/base shifts on the human airway calibre.

    NARCIS (Netherlands)

    Brijker, F.; Elshout, F.J.J. van den; Heijdra, Y.F.; Bosch, F.H.; Folgering, H.T.M.

    2001-01-01

    Acute metabolic alkalosis (NaHCO(3)), acidosis (NH(4)Cl), and placebo (NaCl) were induced in 15 healthy volunteers (12 females, median age 34 (range 24-56) years) in a double blind, placebo controlled study to evaluate the presence of the effects on airway calibre. Acid-base shifts were determined

  16. Evaluation of the number of ionogenic groups of inulinase by acid-base titration.

    Science.gov (United States)

    Kovaleva, T A; Holyavka, M G; Rezvan, S G; Kozhedub, S V

    2008-06-01

    Acid base titration showed that Aspergillus awamori inulinase includes 178 asparaginic and glutamic acid residues, 20 histidine, 10 serine, and 34 lysine and tyrosine residues. Denaturation temperature for this enzyme was calculated using analysis of the proportion of stabilizing and destabilizing amino acids in the molecule.

  17. Acid-base titration curves in an integrated computer learning environment

    NARCIS (Netherlands)

    Heck, A.; Kędzierska, E.; Rodgers, L.; Chmurska, M.

    2008-01-01

    The topic of acid-base reactions is a regular component of many chemistry curricula that requires integrated understanding of various areas of introductory chemistry. Many students have considerable difficulties understanding the concepts and processes involved. It has been suggested and confirmed

  18. Effect of benzoic acid supplementation on acid-base status and mineralmetabolism in catheterized growing pigs

    DEFF Research Database (Denmark)

    Nørgaard, Jan Værum; Fernández, José Adalberto; Sørensen, Kristina Ulrich

    2010-01-01

    Benzoic acid (BA) in diets for growing pigs results in urinary acidification and reduced ammonia emission. The objective was to study the impact of BA supplementation on the acid-base status and mineral metabolism in pigs. Eight female 50-kg pigs, fitted with a catheter in the abdominal aorta, were...

  19. Acid-base and hormonal abnormalities in dogs with naturally occurring diabetes mellitus.

    Science.gov (United States)

    Durocher, Lawren L; Hinchcliff, Kenneth W; DiBartola, Stephen P; Johnson, Susan E

    2008-05-01

    To examine acid-base and hormonal abnormalities in dogs with diabetes mellitus. Cross-sectional study. 48 dogs with diabetes mellitus and 17 healthy dogs. Blood was collected and serum ketone, glucose, lactate, electrolytes, insulin, glucagon, cortisol, epinephrine, norepinephrine, nonesterified fatty acid, and triglyceride concentrations were measured. Indicators of acid-base status were calculated and compared between groups. Serum ketone and glucose concentrations were significantly higher in diabetic than in healthy dogs, but there was no difference in venous blood pH or base excess between groups. Anion gap and strong ion difference were significantly higher and strong ion gap and serum bicarbonate concentration were significantly lower in the diabetic dogs. There were significant linear relationships between measures of acid-base status and serum ketone concentration, but not between measures of acid-base status and serum lactate concentration. Serum insulin concentration did not differ significantly between groups, but diabetic dogs had a wider range of values. All diabetic dogs with a serum ketone concentration > 1,000 micromol/L had a serum insulin concentration diabetic dogs was related to the glucagon-insulin ratio with only low concentrations of insulin required to prevent ketosis. Acidosis in ketotic dogs was attributable largely to high serum ketone concentrations.

  20. Nutrient intake, acid base status and weight gain in water buffalo ...

    African Journals Online (AJOL)

    The impact of different dietary levels of sodium bicarbonate (NaHCO3) on nutrient intake, acid-base status, nitrogen balance and weight gain was examined in growing male buffalo (Bubalus bubalis) calves exposed to hot summer conditions. In a complete randomized block design 60 animals of similar age and weight ...

  1. Adding lactate to the prime solution during hypothermic cardiopulmonary bypass: a quantitative acid-base analysis

    NARCIS (Netherlands)

    Himpe, D.; Neels, H.; de Hert, S.; van Cauwelaert, P.

    2003-01-01

    BACKGROUND: The effect of adding lactate to the cardiopulmonary bypass (CPB) prime was investigated using Stewart's quantitative acid-base approach. According to this quantitative model, serum pH and bicarbonate are determined by three independent factors: the partial pressure of carbon dioxide

  2. Effect of Intravenously Administered Crystalloid Solutions on Acid-Base Balance in Domestic Animals.

    Science.gov (United States)

    Muir, W

    2017-09-01

    Intravenous fluid therapy can alter plasma acid-base balance. The Stewart approach to acid-base balance is uniquely suited to identify and quantify the effects of the cationic and anionic constituents of crystalloid solutions on plasma pH. The plasma strong ion difference (SID) and weak acid concentrations are similar to those of the administered fluid, more so at higher administration rates and with larger volumes. A crystalloid's in vivo effects on plasma pH are described by 3 general rules: SID > [HCO3-] increases plasma pH (alkalosis); SID solutions has little to no effect on plasma pH because of their low titratable acidity. Appreciation of IV fluid composition and an understanding of basic physicochemical principles provide therapeutically valuable insights about how and why fluid therapy can produce and correct alterations of plasma acid-base equilibrium. The ideal balanced crystalloid should (1) contain species-specific concentrations of key electrolytes (Na + , Cl - , K + , Ca ++ , Mg ++ ), particularly Na + and Cl - ; (2) maintain or normalize acid-base balance (provide an appropriate SID); and (3) be isosmotic and isotonic (not induce inappropriate fluid shifts) with normal plasma. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  3. Students' Understanding of Acid, Base and Salt Reactions in Qualitative Analysis.

    Science.gov (United States)

    Tan, Kim-Chwee Daniel; Goh, Ngoh-Khang; Chia, Lian-Sai; Treagust, David F.

    2003-01-01

    Uses a two-tier, multiple-choice diagnostic instrument to determine (n=915) grade 10 students' understanding of the acid, base, and salt reactions involved in basic qualitative analysis. Reports that many students did not understand the formation of precipitates and the complex salts, acid/salt-base reactions, and thermal decomposition involved in…

  4. Acid-Base Chemistry According to Robert Boyle: Chemical Reactions in Words as well as Symbols

    Science.gov (United States)

    Goodney, David E.

    2006-01-01

    Examples of acid-base reactions from Robert Boyle's "The Sceptical Chemist" are used to illustrate the rich information content of chemical equations. Boyle required lengthy passages of florid language to describe the same reaction that can be done quite simply with a chemical equation. Reading or hearing the words, however, enriches the student's…

  5. Effects of Propanidid and Thiopentone on the Acid-Base Status of ...

    African Journals Online (AJOL)

    The effects of propanidid and thiopentone on the acidbase status of babies delivered by elective Caesarean section have been compared. The only significant difference between the 2 groups was the lower umbilical cord venous blood pCO) levels in the propanidid group. The acid-base status in both these groups of ...

  6. The Acid-Base Titration of a Very Weak Acid: Boric Acid

    Science.gov (United States)

    Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

    2012-01-01

    A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

  7. Interactive Computer-Assisted Instruction in Acid-Base Physiology for Mobile Computer Platforms

    Science.gov (United States)

    Longmuir, Kenneth J.

    2014-01-01

    In this project, the traditional lecture hall presentation of acid-base physiology in the first-year medical school curriculum was replaced by interactive, computer-assisted instruction designed primarily for the iPad and other mobile computer platforms. Three learning modules were developed, each with ~20 screens of information, on the subjects…

  8. Acid-base indicator properties of dyes from local plants I: Dyes from ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    ABSTRACT: The acid-base indicator properties of aqueous and ethanol extracts from calyces of H. sabdariffa (Zobo) and a dye obtained from the ripe fruits of Basella alba (Indian spinach), two local plants, were investigated. A purple coloured dye obtained from the ripe fruits of Basella alba showed a λmax at. 580nm ...

  9. Isoelectric Point, Electric Charge, and Nomenclature of the Acid-Base Residues of Proteins

    Science.gov (United States)

    Maldonado, Andres A.; Ribeiro, Joao M.; Sillero, Antonio

    2010-01-01

    The main object of this work is to present the pedagogical usefulness of the theoretical methods, developed in this laboratory, for the determination of the isoelectric point (pI) and the net electric charge of proteins together with some comments on the naming of the acid-base residues of proteins. (Contains 8 figures and 4 tables.)

  10. Lewis Acid-Base Properties of a Low Carbon Aluminium Killed Steel ...

    African Journals Online (AJOL)

    An important factor in achieving maximum adhesion of a particular coating system to the substrate lies in the proper preparation of the substrate prior to the application of paint. The Lewis acid-base properties of the outer metal surface play a determinant role in many of these applications, and the chemical reactions involved ...

  11. The incidence of electrolyte and acid-base abnormalities in critically ...

    African Journals Online (AJOL)

    Background: Electrolytes and acid-base disorders are common challenges seen in the intensive care unit (ICU) resulting in difficulty in weaning patients off the ventilator, prolonged admission periods, preventable cardiac arrhythmias and cardiac arrest. These require prompt lab results most of which are done serially, ...

  12. Maternal and Fetal Acid-Base Chemistry: A Major Determinant of ...

    African Journals Online (AJOL)

    Very small changes in pH may significantly affect the function of various fetal organ systems, such as the central nervous system, and the cardiovascular system with associated fetal distress and poor Apgar score. Review of existing data on maternal-fetal acid-base balance in pregnancy highlight the factors that are ...

  13. 77 FR 16126 - Microbiology Devices; Reclassification of Nucleic Acid-Based Systems for Mycobacterium tuberculosis

    Science.gov (United States)

    2012-03-19

    ... benefit of rapid detection of infection in patients with suspected tuberculosis as compared to traditional means of diagnosis. For patients with acid-fast smear negative tuberculosis, nucleic acid- based in... identification of patients with active tuberculosis may have significant benefits to the infected patient by...

  14. [Development and practice evaluation of blood acid-base imbalance analysis software].

    Science.gov (United States)

    Chen, Bo; Huang, Haiying; Zhou, Qiang; Peng, Shan; Jia, Hongyu; Ji, Tianxing

    2014-11-01

    To develop a blood gas, acid-base imbalance analysis computer software to diagnose systematically, rapidly, accurately and automatically determine acid-base imbalance type, and evaluate the clinical application. Using VBA programming language, a computer aided diagnostic software for the judgment of acid-base balance was developed. The clinical data of 220 patients admitted to the Second Affiliated Hospital of Guangzhou Medical University were retrospectively analyzed. The arterial blood gas [pH value, HCO(3)(-), arterial partial pressure of carbon dioxide (PaCO₂)] and electrolytes included data (Na⁺ and Cl⁻) were collected. Data were entered into the software for acid-base imbalances judgment. At the same time the data generation was calculated manually by H-H compensation formula for determining the type of acid-base imbalance. The consistency of judgment results from software and manual calculation was evaluated, and the judgment time of two methods was compared. The clinical diagnosis of the types of acid-base imbalance for the 220 patients: 65 cases were normal, 90 cases with simple type, mixed type in 41 cases, and triplex type in 24 cases. The accuracy of the judgment results of the normal and triplex types from computer software compared with which were calculated manually was 100%, the accuracy of the simple type judgment was 98.9% and 78.0% for the mixed type, and the total accuracy was 95.5%. The Kappa value of judgment result from software and manual judgment was 0.935, P=0.000. It was demonstrated that the consistency was very good. The time for software to determine acid-base imbalances was significantly shorter than the manual judgment (seconds:18.14 ± 3.80 vs. 43.79 ± 23.86, t=7.466, P=0.000), so the method of software was much faster than the manual method. Software judgment can replace manual judgment with the characteristics of rapid, accurate and convenient, can improve work efficiency and quality of clinical doctors and has great

  15. Investigation of surfactant mediated acid-base charging of mineral oxide particles dispersed in apolar systems.

    Science.gov (United States)

    Gacek, Matthew M; Berg, John C

    2012-12-21

    The current work examines the role of acid-base properties on particle charging in apolar media. Manipulating the polarity and magnitude of charge in such systems is of growing interest to a number of applications. A major hurdle to the implementation of this technology is that the mechanism(s) of particle charging remain a subject of debate. The authors previously conducted a study of the charging of a series of mineral oxide particles dispersed in apolar systems that contained the surfactant AOT. It was observed that there was a correlation between the particle electrophoretic mobility and the acid-base nature of the particle, as characterized by aqueous point of zero charge (PZC) or the isoelectric point (IEP). The current study investigates whether or not a similar correlation is observed with other surfactants, namely, the acidic Span 80 and the basic OLOA 11000. This is accomplished by measuring the electrophoretic mobility of a series of mineral oxides that are dispersed in Isopar-L containing various concentrations of either Span 80 or OLOA 11000. The mineral oxides used have PZC values that cover a wide range of pH, providing a systematic study of how particle and surfactant acid-base properties impact particle charge. It was found that the magnitude and polarity of particle surface charge varied linearly with the particle PZC for both surfactants used. In addition, the point at which the polarity of charge reversed for the basic surfactant OLOA 11000 was shifted to a pH of approximately 8.5, compared to the previous result of about 5 for AOT. This proves that both surfactant and particle acid-base properties are important, and provides support for the theory of acid-base charging in apolar media.

  16. Comparative evaluation of determinations of air activation produced by medical accelerators using triazole and malonic acid or a Geiger-Mueller counting circuit

    International Nuclear Information System (INIS)

    Neumann, K.

    1989-01-01

    The radioactivity levels of irradiated air were measured directly using a Geiger-Mueller counting circuit and compared to the activity of irradiated tablets consisting of solid-state malonic acid and triazole, which was determined by means of a scintillation counter. During studies in various accelerator plants in North Rhine-Westphalia parallel measurements were carried out on the basis of the two methods described above. In order to determine the percentage shares of nitrogen and oxygen in the total amount of radioactivity the values measured were further analysed using the linear regression procedure and the method of the least squares according to Gauss. The combined use of the data obtained and suitable mathematical models permitted average values to be calculated for the activity concentrations occurring during a predetermined period of time under clinical conditions in the area of irradiation. Even in a set of unfavourable circumstances did these prove to be appreciably below the threshold values mandated by the radiation protection laws for individuals at risk of occupational radiation exposure. (orig./DG) [de

  17. Acid-Base Behavior in Hydrothermal Processing of Wastes - Final Report

    International Nuclear Information System (INIS)

    Johnston, K.; Rossky, P.

    2000-01-01

    A major obstacle to development of hydrothermal oxidation technology has been a lack of scientific knowledge of chemistry in hydrothermal solution above 350 C, particularly acid-base behavior, and transport phenomena, which is needed to understand corrosion, metal-ion complexation, and salt precipitation and recovery. Our objective has been to provide this knowledge with in situ UV-visible spectroscopic measurements and fully molecular computer simulation. Our recent development of relatively stable organic UV-visible pH indicators for supercritical water oxidation offers the opportunity to characterize buffers and to monitor acid-base titrations. These results have important implications for understanding reaction pathways and yields for decomposition of wastes in supercritical water

  18. Optical Absorption and Electron Injection of 4-(Cyanomethylbenzoic Acid Based Dyes: A DFT Study

    Directory of Open Access Journals (Sweden)

    Yuehua Zhang

    2015-01-01

    Full Text Available Density functional theory (DFT and time-dependent density functional theory (TDDFT calculations were carried out to study the ground state geometries, electronic structures, and absorption spectra of 4-(cyanomethylbenzoic acid based dyes (AG1 and AG2 used for dye-sensitized solar cells (DSSCs. The excited states properties and the thermodynamical parameters of electron injection were studied. The results showed that (a two dyes have uncoplanar structures along the donor unit and conjugated bridge space, (b two sensitizers exhibited intense absorption in the UV-Vis region, and (c the excited state oxidation potential was higher than the conduction band edge of TiO2 photoanode. As a result, a solar cell based on the 4-(cyanomethylbenzoic acid based dyes exhibited well photovoltaic performance. Furthermore, nine dyes were designed on the basis of AG1 and AG2 to improve optical response and electron injection.

  19. Simulation of Acid-Base Reactions in a Microscale Confined Impinging Jet Reactor

    Science.gov (United States)

    Olsen, Jen; Griffith, Lucas; Olsen, Michael; Fox, Rodney

    2009-11-01

    Numerical simulations were performed of reactive mixing in a microscale confined impinging jets reactor (CIJR). A simple acid-base reaction was modeled and solved for a laminar flow case. Local pH throughout the reactor was determined as a function of hydrogen and hydroxide mixture fraction, and this relationship was used to generate a pH field that could be compared with experimental results. An experimental visualization of the acid-base reaction was performed in the CIJR with phenolphthalein used as a pH indicator. Visualization images of the actual flow were then compared with the predictions of the simulation. Good agreement was observed between the experiment and the simulation. Future work will include adding a turbulence model to the simulation.

  20. Environmental and Chemical Aging of Fatty-Acid-Based Vinyl Ester Composites

    Science.gov (United States)

    2011-04-01

    developed (4). Fatty- acid vinyl esters (FAVEs) use methacrylated fatty- acid monomers, such as methacrylated lauric acid , as reactive diluents to...methacrylated lauric acid with 25-weight-percent styrene). Table 1. Proposed applications for commercial vinyl ester and FAVE composites in the U.S...Environmental and Chemical Aging of Fatty- Acid -Based Vinyl Ester Composites by Steven E. Boyd and John J. La Scala ARL-TR-5523 April

  1. Acid-base properties of humic and fulvic acids formed during composting.

    Science.gov (United States)

    Plaza, César; Senesi, Nicola; Polo, Alfredo; Brunetti, Gennaro

    2005-09-15

    The soil acid-base buffering capacity and the biological availability, mobilization, and transport of macro- and micronutrients, toxic metal ions, and xenobiotic organic cations in soil are strongly influenced by the acid-base properties of humic substances, of which humic and fulvic acids are the major fractions. For these reasons, the proton binding behavior of the humic acid-like (HA) and fulvic acid-like (FA) fractions contained in a compost are believed to be instrumental in its successful performance in soil. In this work, the acid-base properties of the HAs and FAs isolated from a mixture of the sludge residue obtained from olive oil mill wastewater (OMW) evaporated in an open-air pond and tree cuttings (TC) at different stages of composting were investigated by a current potentiometric titration method and the nonideal competitive adsorption (NICA)-Donnan model. The NICA-Donnan model provided an excellent description of the acid-base titration data, and pointed out substantial differences in site density and proton-binding affinity between the HAs and FAs examined. With respect to FAs, HAs were characterized by a smaller content of carboxylic- and phenolic-type groups and their larger affinities for proton binding. Further, HAs featured a greater heterogeneity in carboxylic-type groups than FAs. The composting process increased the content and decreased the proton affinity of carboxylic- and phenolic-type groups of HAs and FAs, and increased the heterogeneity of phenolic-type groups of HAs. As a whole, these effects indicated that the composting process could produce HA and FA fractions with greater cation binding capacities. These results suggest that composting of organic materials improves their agronomic and environmental value by increasing their potential to retain and exchange macro- and micronutrients, and to reduce the bioavailability of organic and inorganic pollutants.

  2. Nutrient intake, acid base status and weight gain in water buffalo ...

    African Journals Online (AJOL)

    Calves fed the 14SB and 16SB diets gained more weight than those fed the 0SB and 4SB diets. These results indicate that the best nutrient intake, acid-base status, nitrogen retention and weight gain occurred in the calves receiving the diet containing 1.2% NaHCO3. Keywords: Bubalus bubalis, buffer, ruminal pH, acidosis, ...

  3. Acid base imbalances in ill neonatal foals and their association with survival.

    Science.gov (United States)

    Viu, J; Armengou, L; Ríos, J; Cesarini, C; Jose-Cunilleras, E

    2017-01-01

    Acid-base imbalances observed in human paediatric patients are associated with outcome. Likewise, neonatal foals may have different acid-base imbalances associated with diagnosis or prognosis. To determine acid-base imbalances by the quantitative method in ill neonatal foals and assess their association with diagnosis and prognosis. Observational prospective clinical study. This study included 65 ill neonatal foals (32 septic, 33 nonseptic) admitted to an equine referral hospital from 2005 to 2011with acid-base parameters determined on admission and a control group of 33 healthy neonatal foals. Blood pH, pCO 2 , sodium, potassium, chloride, L-lactate, albumin and phosphate concentrations were determined. Bicarbonate, globulin, measured strong ion difference (SID m ), nonvolatile weak buffer concentrations (A tot ), base excess and its components were calculated. Analysis of covariance (ANCOVA) and multiple linear regression statistical analyses were performed. Results are summarised as mean ± s.d. for normally distributed variables and median [25-75th percentiles] for non-normally distributed ones. A total of 63% of ill foals had respiratory alkalosis and 58.5% had SID m acidosis. The combination of both alterations was detected in 21 of 65 ill foals and abnormal pH was found in 24 of 65. Compared with healthy foals, ill foals had significantly lower SID m (nonseptic 31.6 ± 6.3 [Pacid-base imbalances observed in ill foals were respiratory alkalosis, SID m acidosis or mixed respiratory alkalosis with strong ion acidosis. Increased venous pCO 2 and blood L-lactate concentration were associated with poor outcome. © 2015 EVJ Ltd.

  4. Influence of dissolved organic carbon content on modelling natural organic matter acid-base properties.

    Science.gov (United States)

    Garnier, Cédric; Mounier, Stéphane; Benaïm, Jean Yves

    2004-10-01

    Natural organic matter (NOM) behaviour towards proton is an important parameter to understand NOM fate in the environment. Moreover, it is necessary to determine NOM acid-base properties before investigating trace metals complexation by natural organic matter. This work focuses on the possibility to determine these acid-base properties by accurate and simple titrations, even at low organic matter concentrations. So, the experiments were conducted on concentrated and diluted solutions of extracted humic and fulvic acid from Laurentian River, on concentrated and diluted model solutions of well-known simple molecules (acetic and phenolic acids), and on natural samples from the Seine river (France) which are not pre-concentrated. Titration experiments were modelled by a 6 acidic-sites discrete model, except for the model solutions. The modelling software used, called PROSECE (Programme d'Optimisation et de SpEciation Chimique dans l'Environnement), has been developed in our laboratory, is based on the mass balance equilibrium resolution. The results obtained on extracted organic matter and model solutions point out a threshold value for a confident determination of the studied organic matter acid-base properties. They also show an aberrant decreasing carboxylic/phenolic ratio with increasing sample dilution. This shift is neither due to any conformational effect, since it is also observed on model solutions, nor to ionic strength variations which is controlled during all experiments. On the other hand, it could be the result of an electrode troubleshooting occurring at basic pH values, which effect is amplified at low total concentration of acidic sites. So, in our conditions, the limit for a correct modelling of NOM acid-base properties is defined as 0.04 meq of total analysed acidic sites concentration. As for the analysed natural samples, due to their high acidic sites content, it is possible to model their behaviour despite the low organic carbon concentration.

  5. The acid-base character of interactions between xenon and selected carboxylic and sulfonic acids

    Science.gov (United States)

    Gąszowski, Dawid; Ilczyszyn, Marek

    2017-05-01

    Interactions of Xe atoms with RCO2H and RSO3H (R = CH3 and CF3) acids in different solvents are examined by analysis of 129Xe chemical shifts extrapolated to zero solvent concentration. Obtained results are very sensitive to the Xe contacts with the methyl and trifluoromethyl groups as well as with the carboxylic and sulfonic groups of different acidity. The acid-base character of these acid-Xe interactions is considered.

  6. Contemporary nucleic acid-based molecular techniques for detection, identification, and characterization of Bifidobacterium.

    Science.gov (United States)

    Mianzhi, Yao; Shah, Nagendra P

    2017-03-24

    Bifidobacteria are one of the most important bacterial groups found in the gastrointestinal tract of humans. Medical and food industry researchers have focused on bifidobacteria because of their health-promoting properties. Researchers have historically relied on classic phenotypic approaches (culture and biochemical tests) for detection and identification of bifidobacteria. Those approaches still have values for the identification and detection of some bifidobacterial species, but they are often labor-intensive and time-consuming and can be problematic in differentiating closely related species. Rapid, accurate, and reliable methods for detection, identification, and characterization of bifidobacteria in a mixed bacterial population have become a major challenge. The advent of nucleic acid-based molecular techniques has significantly advanced isolation and detection of bifidobacteria. Diverse nucleic acid-based molecular techniques have been employed, including hybridization, target amplification, and fingerprinting. Certain techniques enable the detection, characterization, and identification at genus-, species-, and strains-levels, whereas others allow typing of species or strains of bifidobacteria. In this review, an overview of methodological principle, technique complexity, and application of various nucleic acid-based molecular techniques for detection, identification, and characterization of bifidobacteria is presented. Advantages and limitations of each technique are discussed, and significant findings based on particular techniques are also highlighted.

  7. A method for improving the calculation accuracy of acid-base constants by inverse gas chromatography.

    Science.gov (United States)

    Shi, Baoli; Qi, Dawei

    2012-03-30

    In this paper, studies were conducted in order to improve the calculation accuracy of acid-base constants measured by inverse gas chromatography. The conventional a·(γ(d)(l))(0.5) parameters of DCM (dichloromethane), TCM (trichloromethane), and EtAcet (ethyl acetate) were corrected as 185, 212, and 235 Å(2)(mJ/m(2))(0.5) by analyzing the relationship between a·(γ(d)(l))(0.5) and the boiling temperature of the probe solvents, where a is molecular area and γ(l)(d) is surface dispersive free energy of the probe solvents, respectively. To validate the availability of the new a·(γ(d)(l))(0.5) values, the acid-base constants of polystyrene were measured. It was found that when the new a·(γ(d)(l))(0.5) parameters were adopted, the final linear fit degree for the plot of -ΔH(a)(s)/AN* versus DN/AN* was enhanced from 0.993 to 0.999, and the standard deviation was decreased from 0.344 to 0.156. In addition, the availability of general application to improving the calculation accuracy of acid-base constants with the new a·(γ(d)(l))(0.5) parameters was also proved with a mathematical justification. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Effects of aqueous and acid-based coloring liquids on the hardness of zirconia restorations.

    Science.gov (United States)

    Nam, Ji-Young; Park, Mi-Gyoung

    2017-05-01

    The effects of the application of aqueous coloring liquids on the mechanical properties of zirconia have not yet been investigated. The purpose of this in vitro study was to evaluate the effects of 3 different coloring techniques and the number of coloring liquid applications on the hardness of zirconia. Eighty specimens were divided into 8 groups (n=10); nonshaded zirconia, preshaded zirconia, acid-based coloring liquid zirconia, and aqueous coloring liquid zirconia (1, 3, 6). Vickers hardness was measured. Data were analyzed via 1-way and 2-way ANOVAs. Multiple comparisons were performed using a Scheffé test (α=.05). Statistically significant differences in hardness were found between acid-based coloring liquid zirconia and aqueous coloring liquid zirconia (Pzirconia (Pzirconia (P>.05). Within the limitations of this study, the hardness of zirconia was influenced to differing degrees depending on coloring technique. The number of coloring liquid applications affected the hardness of zirconia colored with the acid-based coloring liquid but not the hardness of zirconia colored with the aqueous coloring liquid. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  9. Aqueous extracts of Mozambican plants as alternative and environmentally safe acid-base indicators.

    Science.gov (United States)

    Macuvele, Domingos Lusitaneo Pier; Sithole, Gerre Zebedias Samo; Cesca, Karina; Macuvele, Suzana Lília Pinare; Matsinhe, Jonas Valente

    2016-06-01

    Indicators are substances that change color as the pH of the medium. Many of these substances are dyes of synthetic origin. The mulala plant (Euclea natalensis), which roots are commonly used by rural communities for their oral hygiene, and roseira (Hibiscus rosa-sinensis), an ornamental plant, are abundant in Mozambique. Currently, synthetic acid-base indicators are most commonly used but have environmental implications and, on the other hand, are expensive products, so the demand for natural indicators started. This study investigated the applicability of aqueous extracts of H. rosa-sinensis and E. natalensis as acid-base indicators. Ground on this work, the extracts can be used as acid-base indicators. On the basis of the absorption spectroscopy in both the UV-Vis region and previous studies, it was possible to preliminarily pinpoint anthocyanins and naphthoquinones as responsible for the shifting of colors depending on the pH range of aqueous extracts of H. rosa-sinensis and E. natalensis. These natural indicators are easily accessible, inexpensive, easy to extract, environmentally safe, and locally available.

  10. Biodegradation and Osteosarcoma Cell Cultivation on Poly(aspartic acid) Based Hydrogels.

    Science.gov (United States)

    Juriga, Dávid; Nagy, Krisztina; Jedlovszky-Hajdú, Angéla; Perczel-Kovách, Katalin; Chen, Yong Mei; Varga, Gábor; Zrínyi, Miklós

    2016-09-14

    Development of novel biodegradable and biocompatible scaffold materials with optimal characteristics is important for both preclinical and clinical applications. The aim of the present study was to analyze the biodegradability of poly(aspartic acid)-based hydrogels, and to test their usability as scaffolds for MG-63 osteoblast-like cells. Poly(aspartic acid) was fabricated from poly(succinimide) and hydrogels were prepared using natural amines as cross-linkers (diaminobutane and cystamine). Disulfide bridges were cleaved to thiol groups and the polymer backbone was further modified with RGD sequence. Biodegradability of the hydrogels was evaluated by experiments on the base of enzymes and cell culture medium. Poly(aspartic acid) hydrogels possessing only disulfide bridges as cross-links proved to be degradable by collagenase I. The MG-63 cells showed healthy, fibroblast-like morphology on the double cross-linked and RGD modified hydrogels. Thiolated poly(aspartic acid) based hydrogels provide ideal conditions for adhesion, survival, proliferation, and migration of osteoblast-like cells. The highest viability was found on the thiolated PASP gels while the RGD motif had influence on compacted cluster formation of the cells. These biodegradable and biocompatible poly(aspartic acid)-based hydrogels are promising scaffolds for cell cultivation.

  11. NaVirCept - Nucleic Acid-Based Anti-Viral Project

    International Nuclear Information System (INIS)

    Stephen, E. R.; Wong, J.; Van Loon, D.

    2007-01-01

    Vaccines are generally considered to be the most effective countermeasures to bacterial and viral diseases, however, licensed vaccines against many disease agents are either not available or their efficacies have not been demonstrated. Vaccines are generally agent specific in terms of treatment spectrum and are subject to defeat through natural mutation or through directed efforts. With respect to viral therapeutics, one of the major limitations associated with antiviral drugs is acquired drug resistance caused by antigenic shift or drift. A number of next-generation prophylactic and/or therapeutic measures are on the horizon. Of these, nucleic acid-based drugs are showing great antiviral potential. These drugs elicit long-lasting, broad spectrum protective immune responses, especially to respiratory viral pathogens. The Nucleic Acid-Based Antiviral (NaVirCept) project provides the opportunity to demonstrate the effectiveness of novel medical countermeasures against military-significant endemic and other viral threat agents. This project expands existing DRDC drug delivery capability development, in the form of proprietary liposome intellectual property, by coupling it with leading-edge nucleic acid-based technology to deliver effective medical countermeasures that will protect deployed personnel and the warfighter against a spectrum of viral disease agents. The technology pathway will offer a means to combat emerging viral diseases or modified threat agents such as the bird flu or reconstructed Spanish flu without going down the laborious, time-consuming and expensive paths to develop countermeasures for each new and/or emerging viral disease organism.(author)

  12. Acid-Base Chemistry of White Wine: Analytical Characterisation and Chemical Modelling

    Directory of Open Access Journals (Sweden)

    Enrico Prenesti

    2012-01-01

    Full Text Available A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria. Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture, ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic “wine” especially adapted for testing.

  13. The evolution of mammalian hibernation: lessons from comparative acid-base physiology.

    Science.gov (United States)

    Malan, André

    2014-09-01

    The conquest of land has endowed air-breathers with the capability to utilize ventilation not only to acquire oxygen but also to control blood and intracellular acid-base state. Hypercapnic acidosis (resulting from ventilatory control and/or behavioral choice), thus, has become a universal component of hypometabolic states in air-breathers, with inhibitory and/or protective roles. Here, special emphasis is placed on the understanding of alterations of acid-base state associated with changes in temperature. Hypercapnic acidosis in connection with hypometabolism has been found in a variety of air-breathing clades, from snails to mammals through lungfish, amphibians, and reptiles. The discovery of the plesiomorphic character of mammalian hibernation has made the transfer to hibernation biology of the experience gained in the application of hypercapnic acidosis (the so-called "pH-stat" procedure) relevant to acid-base control in clinical artificial hypothermia. This paves the way for mutual benefits from such reciprocal exchange of information between hibernation biology and clinical applications. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  14. Acid-base chemistry of white wine: analytical characterisation and chemical modelling.

    Science.gov (United States)

    Prenesti, Enrico; Berto, Silvia; Toso, Simona; Daniele, Pier Giuseppe

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic "wine" especially adapted for testing.

  15. Acid-Base Chemistry of White Wine: Analytical Characterisation and Chemical Modelling

    Science.gov (United States)

    Prenesti, Enrico; Berto, Silvia; Toso, Simona; Daniele, Pier Giuseppe

    2012-01-01

    A chemical model of the acid-base properties is optimized for each white wine under study, together with the calculation of their ionic strength, taking into account the contributions of all significant ionic species (strong electrolytes and weak one sensitive to the chemical equilibria). Coupling the HPLC-IEC and HPLC-RP methods, we are able to quantify up to 12 carboxylic acids, the most relevant substances responsible of the acid-base equilibria of wine. The analytical concentration of carboxylic acids and of other acid-base active substances was used as input, with the total acidity, for the chemical modelling step of the study based on the contemporary treatment of overlapped protonation equilibria. New protonation constants were refined (L-lactic and succinic acids) with respect to our previous investigation on red wines. Attention was paid for mixed solvent (ethanol-water mixture), ionic strength, and temperature to ensure a thermodynamic level to the study. Validation of the chemical model optimized is achieved by way of conductometric measurements and using a synthetic “wine” especially adapted for testing. PMID:22566762

  16. Elucidating the hard/soft acid/base principle: A perspective based on half-reactions

    International Nuclear Information System (INIS)

    Ayers, Paul W.; Parr, Robert G.; Pearson, Ralph G.

    2006-01-01

    A comprehensive analysis is presented for the acid-base double-exchange reaction as well as the associated acid-displacement and base-displacement 'half-reactions' with the goal of elucidating the meaning of the hard/soft acid/base (HSAB) principle and the conditions for its validity. When electron-transfer effects are important and other effects are negligible, the HSAB principle is driven by the surpassing stability of the soft acid/soft base product. When electrostatic effects dominate the reactivity, the HSAB principle is driven by the surpassing stability of the hard acid/hard base product. Because electron-transfer effects favor soft/soft interactions, while electrostatic effects favor hard/hard interactions, acid-base exchange reactions may be used to determine whether a reagent's reactivity is dominated by electron-transfer or by electrostatic effects. Because electron-transfer and electrostatic considerations separately favor the HSAB principle whenever the electronic chemical potentials of the acids and bases involved in the reaction are similar, our analysis provides strong support for the HSAB principle. The electronic chemical potential measures the intrinsic strength of acids and bases

  17. Error causes in the determination of the acid-base reactivity of oxi-hydroxides

    International Nuclear Information System (INIS)

    Duc, M.; Lefevre, G.; Fedoroff, M.

    2004-01-01

    The long term safety of radioactive waste depositories is based on the sorption of radionuclides from underground water onto engineered and natural barriers. For a quantitative prediction of the migration in such barriers, we need accurate sorption data. Models should be in agreement with the sorption mechanism. Surface complexation is the most often used model for oxides and hydroxides. In fact, there are several types of surface complexation models such as 1-pK and 2-pK monosite, 1-pK and 2-pK multisite, pK-distribution models. Furthermore, there are several ways to describe the distribution of the electrostatic potential in the vicinity of the solid surface (CCM, DLM, BSM, TLM,..). However, all these models are based on the acid-base properties of superficial hydroxide or oxide groups of the solid. It is necessary to determine the surface charge versus pH (titration curves), the point of zero charge (pzc), the surface density of sites active towards protons and hydroxides in aqueous solutions, the acid-base constants of these sites. These parameters are then used for calculating the sorption constants of ions other than protons and hydroxide ions. It is therefore important to determine these parameters very accurately. A comparison of acid-base parameters published in the literature shows a large scatter for the ''same'' oxides [1,2]. Several causes could explain this scatter. One reason is the use of different models, each electrostatic models leading to different values of site density and constants. However, titration curves and pzc are independent of the model chosen. Another reason may be uncontrolled differences in the composition and purity of oxides. Finally, other causes could be found in the titration procedure, in the solubility and the stability of the solid. In order to understand more about the acid-base properties of oxides and about the origin of the discrepancies between measurements, we have performed a systematic experimental study of several

  18. Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers.

    Science.gov (United States)

    Nap, R J; Tagliazucchi, M; Szleifer, I

    2014-01-14

    This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads

  19. Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers

    Science.gov (United States)

    Nap, R. J.; Tagliazucchi, M.; Szleifer, I.

    2014-01-01

    This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads

  20. The generalized lewis acid-base titration of palladium and niobium

    Science.gov (United States)

    Cima, M.; Brewer, L.

    1988-12-01

    The high thermodynamic stability of alloys composed of platinum group metals and group IVB and VB metals has been explained by an electronic interaction analogous to the Lewis acid-base concept for nontransition elements. The analogy is further demonstrated by the titration of palladium by addition of niobium. The activity of niobium in solid palladium was measured as a function of concentration by solid-state galvanic cells and study of the ternary oxide phase diagram. The galvanic cells were of the type Pt/NbO2,Nb2O4.8/YDTJNbOy,Nbpd/Pt where the solid electrolyte is yttria-doped thoria (YDT). Ternary phase diagrams for the Pd-Nb-0 and Rh-Nb-0 systems were obtained by characterizing samples equilibrated at 1000 °C. The phase relationships found in the ternary diagrams were also used to derive thermochemical data for the alloys. Thermochemical quantities for other acid-base stabilized alloys such as Nb-Rh, Ti-Pd, and Ti-Rh were also measured. The excess partial molar ΔGxs/R of niobium at infinite dilution was determined to be -31 kilo-Kelvin at 1000 °C, and the AG°JR of formation of a mole of NbPd3.55 is —21 kilo-Kelvin. These results and those for the other systems are used to assess the importance of valence electron configuration, nuclear charge, and crystal field effects in the context of generalized Lewis acid-base theory. It is concluded that both the nuclear charge of the atom and crystal field splitting of the valence orbitals significantly affect the basicity of the platinum group metals.

  1. Chemical processes at the surface of various clays on acid-base titration

    International Nuclear Information System (INIS)

    Park, K. K.; Park, Y. S.; Jung, E. C.

    2010-01-01

    The chemical reaction of radionuclides at the interface between groundwater and geological mineral is an important process determining their retardation of transport through groundwater flow in a nuclear waste disposal. Clay minerals are major components of soil and argillaceous rock, and some of them are considered to be important base materials in the design of high-level nuclear waste repository due to their large swelling, low-permeability, large surface area, and strong and large sorption of radionuclides. Clay materials are phyllosilicates containing accessory minerals such as metal oxides, hydroxides, oxyhydroxides. Their structures are condensed 1:1 or 2:1 layers of tetrahedral SiO 3/2 OH and octahedral Al(OH) 6/2 sheets. An accurate knowledge about the properties of clay surface is required as a parameter for a long-term estimation of radionuclide retardation effects. Electric surface charge is a primary property determining ion exchange and surface complexation of radionuclides on its surface. The sources of electric surface charge are a permanent structural negative charge on a basal plane and a dissociable charge at an edge surface. Investigation of proton sorption is a prerequisite to the understanding of radionuclide sorption. The reactions on a permanently charged site and on an edge site are measured by an electrokinetic measurement and by potentiometric titration, respectively. However, side reactions such as complexation, proton/cation exchange, dissolution, hydrolysis, precipitation and re adsorption, and the reaction of secondary minerals hinder an experimental measurement of accurate acid-base properties. This presentation describes the pH change on dispersing various clays in water and adding acid, base or Eu(III) ion to these solutions, and the effect of Eu(III) ion on acid-base titration of clay solutions

  2. Roles of renal ammonia metabolism other than in acid-base homeostasis.

    Science.gov (United States)

    Weiner, I David

    2017-06-01

    The importance of renal ammonia metabolism in acid-base homeostasis is well known. However, the effects of renal ammonia metabolism other than in acid-base homeostasis are not as widely recognized. First, ammonia differs from almost all other solutes in the urine in that it does not result from arterial delivery. Instead, ammonia is produced by the kidney, and only a portion of the ammonia produced is excreted in the urine, with the remainder returned to the systemic circulation through the renal veins. In normal individuals, systemic ammonia addition is metabolized efficiently by the liver, but in patients with either acute or chronic liver disease, conditions that increase the addition of ammonia of renal origin to the systemic circulation can result in precipitation and/or worsening of hyperammonemia. Second, ammonia appears to serve as an intrarenal paracrine signaling molecule. Hypokalemia increases proximal tubule ammonia production and secretion as well as reabsorption in the thick ascending limb of the loop of Henle, thereby increasing delivery to the renal interstitium and the collecting duct. In the collecting duct, ammonia decreases potassium secretion and stimulates potassium reabsorption, thereby decreasing urinary potassium excretion and enabling feedback correction of the initiating hypokalemia. Finally, the stimulation of renal ammonia metabolism by hypokalemia may contribute to the development of metabolic alkalosis, which in turn can stimulate NaCl reabsorption and contribute to the intravascular volume expansion, increased blood pressure and diuretic resistance that can develop with hypokalemia. The evidence supporting these novel non-acid-base roles of renal ammonia metabolism is discussed in this review.

  3. A comparison of traditional and quantitative analysis of acid-base imbalances in hypoalbuminemic dogs.

    Science.gov (United States)

    Torrente, Carlos; Manzanilla, Edgar G; de Gopegui, Rafael Ruiz

    2014-01-01

    To compare the traditional (HH) and quantitative approaches used for the evaluation of the acid-base balance in hypoalbuminemic dogs. Prospective observational study. ICU of a veterinary teaching hospital. One hundred and five client-owned dogs. Jugular venous blood samples were collected from each patient on admission to determine: total plasma protein (TP), albumin (Alb), blood urea nitrogen (BUN), glucose (Glu), hematocrit (HCT), Na(+) , Cl(-) , K(+) , phosphate (Pi ), pH, PvCO2, bicarbonate (HCO3 (-) ), anion gap (AG), adjusted anion gap for albumin (AGalb ) or phosphate (AGalb-phos ), standardized base excess (SBE), strong ion difference (SID), concentration of nonvolatile weak buffers (Atot ), and strong ion gap (SIG). Patients were divided in 2 groups according to the severity of the hypoalbuminemia: mild (Alb = 21-25 g/L) and severe (Alb ≤20 g/L). All parameters were compared among groups. Patients with severe hypoalbuminemia showed significant decrease in TP (P = 0.011), Atot (P = 0.050), and a significant increase in adjusted AG (P = 0.048) and the magnitude of SIG (P = 0.011) compared to animals with mild hypoalbuminemia. According to the HH approach, the most frequent imbalances were simple disorders (51.4%), primarily metabolic acidosis (84.7%) associated with a high AG acidosis. However, when using the quantitative method, 58.1% of patients had complex disorders, with SIG acidosis (74.3%) and Atot alkalosis (33.3%) as the most frequent acid-base imbalances. Agreement between methods only matched in 32 cases (kappa acid-base balance was poor and many imbalances detected using the quantitative approach were missed using the HH approach. Further studies are necessary to confirm the clinical utility of using the quantitative approach in the decision-making process of the severely ill hypoalbuminemic patients. © Veterinary Emergency and Critical Care Society 2014.

  4. Effects of intravenous solutions on acid-base equilibrium: from crystalloids to colloids and blood components.

    Science.gov (United States)

    Langer, Thomas; Ferrari, Michele; Zazzeron, Luca; Gattinoni, Luciano; Caironi, Pietro

    2014-01-01

    Intravenous fluid administration is a medical intervention performed worldwide on a daily basis. Nevertheless, only a few physicians are aware of the characteristics of intravenous fluids and their possible effects on plasma acid-base equilibrium. According to Stewart's theory, pH is independently regulated by three variables: partial pressure of carbon dioxide, strong ion difference (SID), and total amount of weak acids (ATOT). When fluids are infused, plasma SID and ATOT tend toward the SID and ATOT of the administered fluid. Depending on their composition, fluids can therefore lower, increase, or leave pH unchanged. As a general rule, crystalloids having a SID greater than plasma bicarbonate concentration (HCO₃-) cause an increase in plasma pH (alkalosis), those having a SID lower than HCO₃- cause a decrease in plasma pH (acidosis), while crystalloids with a SID equal to HCO₃- leave pH unchanged, regardless of the extent of the dilution. Colloids and blood components are composed of a crystalloid solution as solvent, and the abovementioned rules partially hold true also for these fluids. The scenario is however complicated by the possible presence of weak anions (albumin, phosphates and gelatins) and their effect on plasma pH. The present manuscript summarises the characteristics of crystalloids, colloids, buffer solutions and blood components and reviews their effect on acid-base equilibrium. Understanding the composition of intravenous fluids, along with the application of simple physicochemical rules best described by Stewart's approach, are pivotal steps to fully elucidate and predict alterations of plasma acid-base equilibrium induced by fluid therapy.

  5. Acid-base safety during the course of a very low-calorie-ketogenic diet.

    Science.gov (United States)

    Gomez-Arbelaez, Diego; Crujeiras, Ana B; Castro, Ana I; Goday, Albert; Mas-Lorenzo, Antonio; Bellon, Ana; Tejera, Cristina; Bellido, Diego; Galban, Cristobal; Sajoux, Ignacio; Lopez-Jaramillo, Patricio; Casanueva, Felipe F

    2017-10-01

    Very low-calorie ketogenic (VLCK) diets have been consistently shown to be an effective obesity treatment, but the current evidence for its acid-base safety is limited. The aim of the current work was to evaluate the acid-base status of obese patients during the course of a VLCK diet. Twenty obese participants undertook a VLCK diet for 4 months. Anthropometric and biochemical parameters, and venous blood gases were obtained on four subsequent visits: visit C-1 (baseline); visit C-2, (1-2 months); maximum ketosis; visit C-3 (2-3 months), ketosis declining; and visit C-4 at 4 months, no ketosis. Results were compared with 51 patients that had an episode of diabetic ketoacidosis as well as with a group that underwent a similar VLCK diet in real life conditions of treatment. Visit C1 blood pH (7.37 ± 0.03); plasma bicarbonate (24.7 ± 2.5 mmol/l); plasma glucose (96.0 ± 11.7 mg/l) as well as anion gap or osmolarity were not statistically modified at four months after a total weight reduction of 20.7 kg in average and were within the normal range throughout the study. Even at the point of maximum ketosis all variables measured were always far from the cut-off points established to diabetic ketoacidosis. During the course of a VLCK diet there were no clinically or statistically significant changes in glucose, blood pH, anion gap and plasma bicarbonate. Hence the VLCK diet can be considered as a safe nutritional intervention for the treatment of obesity in terms of acid-base equilibrium.

  6. A computational study of ultrafast acid dissociation and acid-base neutralization reactions. I. The model.

    Science.gov (United States)

    Maurer, Patrick; Thomas, Vibin; Rivard, Ugo; Iftimie, Radu

    2010-07-28

    Ultrafast, time-resolved investigations of acid-base neutralization reactions have recently been performed using systems containing the photoacid 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS) and various Bronsted bases. Two conflicting neutralization mechanisms have been formulated by Mohammed et al. [Science 310, 83 (2005)] and Siwick et al. [J. Am. Chem. Soc. 129, 13412 (2007)] for the same acid-base system. Herein an ab initio molecular dynamics based computational model is formulated, which is able to investigate the validity of the proposed mechanisms in the general context of ground-state acid-base neutralization reactions. Our approach consists of using 2,4,6-tricyanophenol (exp. pKa congruent with 1) as a model for excited-state HPTS( *) (pKa congruent with 1.4) and carboxylate ions for the accepting base. We employ our recently proposed dipole-field/quantum mechanics (QM) treatment [P. Maurer and R. Iftimie, J. Chem. Phys. 132, 074112 (2010)] of the proton donor and acceptor molecules. This approach allows one to tune the free energy of neutralization to any desired value as well as model initial nonequilibrium hydration effects caused by a sudden increase in acidity, making it possible to achieve a more realistic comparison with experimental data than could be obtained via a full-QM treatment of the entire system. It is demonstrated that the dipole-field/QM model reproduces correctly key properties of the 2,4,6-tricyanophenol acid molecule including gas-phase proton dissociation energies and dipole moments, and condensed-phase hydration structure and pKa values.

  7. Impact of the diet on net endogenous acid production and acid-base balance.

    Science.gov (United States)

    Poupin, Nathalie; Calvez, Juliane; Lassale, Camille; Chesneau, Caroline; Tomé, Daniel

    2012-06-01

    Net acid production, which is composed of volatile acids (15,000 mEq/day) and metabolic acids (70-100 mEq/day) is relatively small compared to whole-body H⁺ turnover (150,000 mEq/day). Metabolic acids are ingested from the diet or produced as intermediary or end products of endogenous metabolism. The three commonly reported sources of net acid production are the metabolism of sulphur amino acids, the metabolism or ingestion of organic acids, and the metabolism of phosphate esters or dietary phosphoproteins. Net base production occurs mainly as a result of absorption of organic anions from the diet. To maintain acid-base balance, ingested and endogenously produced acids are neutralized within the body by buffer systems or eliminated from the body through the respiratory (excretion of volatile acid in the form of CO₂) and urinary (excretion of fixed acids and remaining H⁺) pathways. Because of the many reactions involved in the acid-base balance, the direct determination of acid production is complex and is usually estimated through direct or indirect measurements of acid excretion. However, indirect approaches, which assess the acid-forming potential of the ingested diet based on its composition, do not take all the acid-producing reactions into account. Direct measurements therefore seem more reliable. Nevertheless, acid excretion does not truly provide information on the way acidity is dealt with in the plasma and this measurement should be interpreted with caution when assessing acid-base imbalance. Copyright © 2012 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  8. Electrodeposited Fe-Co films prepared from a citric-acid-based plating bath

    OpenAIRE

    Yanai, Takeshi; Uto, H.; Shimokawa, Takaya; Nakano, Masaki; Fukunaga, Hirotoshi; Suzuki, K.

    2013-01-01

    Electrodeposited Fe-Co films are commonly prepared in a boric-acid-based bath. In this research, we applied citric acid instead of boric acid for the plating of Fe-Co films because boron in the waste bath is restricted by environmental-protection regulations in Japan. We evaluated the effect of citric acid on the magnetic and structural properties of the films. The saturation magnetization of the Fe-Co films slightly increased while the Fe content in the Fe-Co films decreased with increasing ...

  9. Acid-base properties of sorbents based on zirconium(IV) phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Bekrenev, A.V. [Research Center of Environmental Safety, St. Petersburg (Russian Federation); Pyartman, A.K. [St. Petersburg Institute of Technology (Russian Federation)

    1995-11-01

    The objective of this work was to investigate the acid-base properties of materials based on zirconium(IV) phosphate and diphosphate and to calculate the equilibrium constants for corresponding heterogeneous reactions of binary ion exchange, that is, to calculate the characteristics of the ion-exchange properties for use in calculating more complicated ion-exchange equilibria. The objects of investigation were zirconium(IV) hydroxyphosphate (ZHP) and zirconium(IV) diphosphate (ZDP), as well as composite materials based on said compounds and a porous support material.

  10. Design, synthesis and structure of new potential electrochemically active boronic acid-based glucose sensors

    DEFF Research Database (Denmark)

    Norrild, Jens Chr.; Søtofte, Inger

    2002-01-01

    In the course of our investigations on new boronic acid based carbohydrate sensors three new boronic acids 3, 7 and 11 containing a ferrocene moiety were synthesised. Their design includes an intramolecular B-N bonding motif in order to facilitate binding at physiological pH. We report...... with structures obtained of 2,4,6-tris[2-(N,N-dimethylaminomethyl)phenyl]boroxin (14) and 2,2-dimethyl-1,3-diyl[2-(N,N-dimethylaminomethyl)phenyl]boronate (15). The structure of 13 shows the existence of intramolecular B-N bonds in the solid phase....

  11. Management of Acute Kidney Injury and Acid-Base Balance in the Septic Patient.

    Science.gov (United States)

    Weyker, Paul D; Pérez, Xosé L; Liu, Kathleen D

    2016-06-01

    Acute kidney injury (AKI) is an abrupt decrease in kidney function that takes place over hours to days. Sepsis is the leading cause of AKI and portends a particularly high morbidity and mortality, although the severity may vary from a transient rise in serum creatinine to end-stage renal disease. With regard to acid-base management in septic AKI, caution should be used with hyperchloremic crystalloid solutions, and dialysis is often used in the setting of severe acidosis. In the future, biomarkers may help clinicians identify AKI earlier and allow for potential interventions before the development of severe AKI. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. [Investigation of reference intervals of blood gas and acid-base analysis assays in China].

    Science.gov (United States)

    Zhang, Lu; Wang, Wei; Wang, Zhiguo

    2015-10-01

    To investigate and analyze the upper and lower limits and their sources of reference intervals in blood gas and acid-base analysis assays. The data of reference intervals were collected, which come from the first run of 2014 External Quality Assessment (EQA) program in blood gas and acid-base analysis assays performed by National Center for Clinical Laboratories (NCCL). All the abnormal values and errors were eliminated. Data statistics was performed by SPSS 13.0 and Excel 2007 referring to upper and lower limits of reference intervals and sources of 7 blood gas and acid-base analysis assays, i.e. pH value, partial pressure of carbon dioxide (PCO2), partial pressure of oxygen (PO2), Na+, K+, Ca2+ and Cl-. Values were further grouped based on instrument system and the difference between each group were analyzed. There were 225 laboratories submitting the information on the reference intervals they had been using. The three main sources of reference intervals were National Guide to Clinical Laboratory Procedures [37.07% (400/1 079)], instructions of instrument manufactures [31.23% (337/1 079)] and instructions of reagent manufactures [23.26% (251/1 079)]. Approximately 35.1% (79/225) of the laboratories had validated the reference intervals they used. The difference of upper and lower limits in most assays among 7 laboratories was moderate, both minimum and maximum (i.e. the upper limits of pH value was 7.00-7.45, the lower limits of Na+ was 130.00-156.00 mmol/L), and mean and median (i.e. the upper limits of K+ was 5.04 mmol/L and 5.10 mmol/L, the upper limits of PCO2 was 45.65 mmHg and 45.00 mmHg, 1 mmHg = 0.133 kPa), as well as the difference in P2.5 and P97.5 between each instrument system group. It was shown by Kruskal-Wallis method that the P values of upper and lower limits of all the parameters were lower than 0.001, expecting the lower limits of Na+ with P value 0.029. It was shown by Mann-Whitney that the statistic differences were found among instrument

  13. The role of acid-base imbalance in statin-induced myotoxicity.

    Science.gov (United States)

    Taha, Dhiaa A; De Moor, Cornelia H; Barrett, David A; Lee, Jong Bong; Gandhi, Raj D; Hoo, Chee Wei; Gershkovich, Pavel

    2016-08-01

    Disturbances in acid-base balance, such as acidosis and alkalosis, have potential to alter the pharmacologic and toxicologic outcomes of statin therapy. Statins are commonly prescribed for elderly patients who have multiple comorbidities such as diabetes mellitus, cardiovascular, and renal diseases. These patients are at risk of developing acid-base imbalance. In the present study, the effect of disturbances in acid-base balance on the interconversion of simvastatin and pravastatin between lactone and hydroxy acid forms have been investigated in physiological buffers, human plasma, and cell culture medium over pH ranging from 6.8-7.8. The effects of such interconversion on cellular uptake and myotoxicity of statins were assessed in vitro using C2C12 skeletal muscle cells under conditions relevant to acidosis, alkalosis, and physiological pH. Results indicate that the conversion of the lactone forms of simvastatin and pravastatin to the corresponding hydroxy acid is strongly pH dependent. At physiological and alkaline pH, substantial proportions of simvastatin lactone (SVL; ∼87% and 99%, respectively) and pravastatin lactone (PVL; ∼98% and 99%, respectively) were converted to the active hydroxy acid forms after 24 hours of incubation at 37°C. At acidic pH, conversion occurs to a lower extent, resulting in greater proportion of statin remaining in the more lipophilic lactone form. However, pH alteration did not influence the conversion of the hydroxy acid forms of simvastatin and pravastatin to the corresponding lactones. Furthermore, acidosis has been shown to hinder the metabolism of the lactone form of statins by inhibiting hepatic microsomal enzyme activities. Lipophilic SVL was found to be more cytotoxic to undifferentiated and differentiated skeletal muscle cells compared with more hydrophilic simvastatin hydroxy acid, PVL, and pravastatin hydroxy acid. Enhanced cytotoxicity of statins was observed under acidic conditions and is attributed to increased

  14. Characterization of Polymer Surfaces by the Use of Different Wetting Theories Regarding Acid-Base Properties

    Directory of Open Access Journals (Sweden)

    Eduard Kraus

    2017-01-01

    Full Text Available The existing wetting methods for the determination of acid-base properties on solid surfaces are discussed. Striving for a better understanding of the adhesive polymer interactions in adhesively joined polymers, the methods of Berger and van Oss-Chaudhury-Good were found as the most suitable methods for the investigation of wetting on solid polymer surfaces. Methods of nonlinear systems by Della Volpe and Siboni were adapted and evaluated on plastic surfaces. In the context of these investigations various data of the surface free energy as well as its components have been identified for a number of polymer surfaces by application of spatial equation solutions.

  15. Prebiotic synthesis of carboxylic acids, amino acids and nucleic acid bases from formamide under photochemical conditions⋆

    Science.gov (United States)

    Botta, Lorenzo; Mattia Bizzarri, Bruno; Piccinino, Davide; Fornaro, Teresa; Robert Brucato, John; Saladino, Raffaele

    2017-07-01

    The photochemical transformation of formamide in the presence of a mixture of TiO2 and ZnO metal oxides as catalysts afforded a large panel of molecules of biological relevance, including carboxylic acids, amino acids and nucleic acid bases. The reaction was less effective when performed in the presence of only one mineral, highlighting the role of synergic effects between the photoactive catalysts. Taken together, these results suggest that the synthesis of chemical precursors for both the genetic and the metabolic apparatuses might have occurred in a simple environment, consisting of formamide, photoactive metal oxides and UV-radiation.

  16. Amino-Acid-Based Polymerizable Surfactants for the Synthesis of Chiral Nanoparticles.

    Science.gov (United States)

    Preiss, Laura C; Wagner, Manfred; Mastai, Yitzhak; Landfester, Katharina; Muñoz-Espí, Rafael

    2016-09-01

    Amino-acid-based chiral surfactants with polymerizable moieties are synthesized, and a versatile approach to prepare particles thereof with a chiral surface functionality is presented. As an example of an application, the synthesized particles are tested for their ability as nucleating agents in the enantioselective crystallization of amino acid conglomerate systems, taking rac-asparagine as a model system. Particles resulting from chiral surfactants with different tail groups are compared and the results demonstrate that only the chiral nanoparticles made of the polymerizable surfactant are able to act efficiently as nucleation agent in enantioselective crystallization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Bis[N,N'-diisopropylbenzamidinato(-)]silicon(II): Lewis acid/base reactions with triorganylboranes.

    Science.gov (United States)

    Junold, Konstantin; Baus, Johannes A; Burschka, Christian; Fonseca Guerra, Célia; Bickelhaupt, F Matthias; Tacke, Reinhold

    2014-09-22

    Reaction of the donor-stabilized silylene 1 (which is three-coordinate in the solid state and four-coordinate in solution) with BEt3 and BPh3 leads to the formation of the Lewis acid/base complexes 2 and 3, respectively, which are the first five-coordinate silicon compounds with an SiB bond. These compounds were structurally characterized by crystal structure analyses and by multinuclear NMR spectroscopic studies in the solid state and in solution. Additionally, the bonding situation in 2 and 3 was analyzed by quantum chemical studies. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Acid-Base Pairs in Lewis Acidic Zeolites Promote Direct Aldol Reactions by Soft Enolization.

    Science.gov (United States)

    Lewis, Jennifer D; Van de Vyver, Stijn; Román-Leshkov, Yuriy

    2015-08-17

    Hf-, Sn-, and Zr-Beta zeolites catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft enolization through α-proton abstraction. The Lewis acidic zeolites maintain activity in the presence of water and, unlike traditional base catalysts, in acidic solutions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. The scaled-charge additive force field for amino acid based ionic liquids

    DEFF Research Database (Denmark)

    Fileti, E. E.; Chaban, V. V.

    2014-01-01

    Ionic liquids (ILs) constitute an emerging research field. New ILs involve more and more organic and inorganic ions. Amino acid based ILs (AAILs) represent a specific interest due to their evolutional connection to proteins. We report a new non-polarizable force field (FF) for the eight AAILs...... comprising 1-ethyl-3-methylimidazolium cation and amino acid anions. The anions were obtained via deprotonation of carboxyl group. Specific cation-anion non-covalent interactions were taken into account by computing electrostatic potential for ion pairs. The van der Waals interactions were adopted from...

  20. Comparison of the structural and physical properties of human hair eumelanin following enzymatic or acid/base extraction.

    Science.gov (United States)

    Liu, Yan; Kempf, Valerie R; Nofsinger, J Brian; Weinert, Emily E; Rudnicki, Mark; Wakamatsu, Kazumasa; Ito, Shosuke; Simon, John D

    2003-08-01

    Eumelanin was isolated from a sample of black, Indonesian human hair using three different published procedures: two different acid/base extractions and an enzymatic extraction. The morphology and spectroscopic properties of the isolated pigments differ significantly. The acid/base procedures both yield an amorphous material, while enzymatic extraction yields ellipsoidal melanosomes. Amino acid analysis shows that there is protein associated with the isolated pigments, accounting for 52, 40 and 14% of the total mass for the two acid/base extractions and the enzymatic extraction, respectively. The amino acid compositions do not correlate with those of keratin or tyrosinase. Metal elemental analysis shows that the acid/base extraction removes a majority of many metal ions bound to the pigment. Chemical degradation analysis by KMnO4/H+ and H2O2/OH- indicates significant differences between the pigments isolated by acid/base and enzymatic extraction. After correction for the protein mass in the two pigments, the lower yields of both pyrrole-2,3,5-tricarboxylic acid and pyrrole-2,3-dicarboxylic acid, eumelanin degradation products, indicate acid/base extraction modifies the chemical structure of the melanin, consistent with the result of Soluene solubilization assay. While the optical absorption spectra of the bulk pigments are similar, the spectra of the molecular weight less than 1000 mass fractions differ significantly. The data clearly indicate that pigment obtained from human hair by acid/base extraction contains significant protein, exhibits destruction of the melanosome, and possesses altered molecular structure. The acid/base extracted hair melanin is not representative of the natural material and is a poor model system for studying the physical and biological properties of melanins. The enzymatically extracted hair melanin, on the contrary, retains the morphology of intact melanosomes and is an excellent source of human melanin.

  1. Investigations of (acid+base) equilibria in systems modelling interactions occurring in biomolecules

    International Nuclear Information System (INIS)

    Kozak, Anna; Czaja, Malgorzata; Chmurzynski, Lech

    2006-01-01

    By using the potentiometric microtitration method, acidity constants, K a , anionic, K AHA - , and cationic, K BHB + , homoconjugation constants, as well as molecular heteroconjugation, K BHA , constants have been determined in (acid+base) systems formed by the following compounds: acetic acid, phenol, n-butylamine, imidazole, and 4(5)-methylimidazole. These compounds constitute fragments of the side chains of amino acids capable of proton exchange in active sites of enzymes. The (acid+base) equilibria were studied in five polar solvents of different properties, namely in aprotic protophobic acetonitrile, acetone and propylene carbonate, in aprotic protophilic dimethyl sulfoxide and in amphiprotic methanol. The lowest values of the acidity constants of the molecular and cationic acids have been found in aprotic protophobic polar solvents - acetonitrile, propylene carbonate and acetone. Their acid strength have been found to depend on solvent basicity expressed as donor numbers, DN. These media, in particular acetonitrile and acetone, are also favourable for establishing molecular homo- and heteroconjugation equilibria. The most stable homocomplexes are formed in the case of acetic acid (K AHA - values range from 2.26 to 3.56 in these media, being more than an order of magnitude higher than those for the remaining compounds). The magnitudes of lgK BHA reveal that the most stable heterocomplexes are formed by n-butylamine and acetic acid that are characterized by the smallest differences in pK a values

  2. Enhanced dispersion of boron nitride nanosheets in aqueous media by using bile acid-based surfactants

    Science.gov (United States)

    Chae, Ari; Park, Soo-Jin; Min, Byunggak; In, Insik

    2018-01-01

    Facile noncovalent surface functionalization of hydroxylated boron nitride nanosheet (BNNS-OH) was attempted through the sonication-assisted exfoliation of h-BN in aqueous media in the presence of bile acid-based surfactants such as sodium cholic acid (SC) or sodium deoxycholic acid (SDC), resulting in SC- or SDC-BNNS-OH dispersion with high up to 2 mg ml‑1 and enhanced dispersion stability due to the increased negative zeta potential. While prepared SC-BNNS-OH revealed multi-layered BNNS structures, the large lateral sizes of hundreds nanometers and clear h-BN lattice structures are very promising for the preparation and application of water-processable BNNS-based nanomaterials. It is regarded that noncovalent functionalization of BNNS-OH based on σ-π interaction between with σ-rich bile acid-based amphiphiles and π-rich BNNS is very effective to formulate multi-functional BNNS-based nanomaterials or hybrids that can be utilized in various applications where both the pristine properties of BNNS and the extra functions are simultaneously required.

  3. American Society of Nephrology quiz and questionnaire 2014: acid-base and electrolyte disorders.

    Science.gov (United States)

    Rosner, Mitchell H; Perazella, Mark A; Choi, Michael J

    2015-03-06

    The Nephrology Quiz and Questionnaire remains an extremely popular session for attendees of the Annual Kidney Week Meeting of the American Society of Nephrology. Once again, in 2014 the conference hall was overflowing with audience members and eager quiz participants. Topics covered by the expert discussants included electrolyte and acid-base disorders, glomerular disease, ESRD/dialysis, and transplantation. Complex cases from each of these categories along with single-best-answer questions were prepared and submitted by the panel of experts. Before the meeting, program directors of United States nephrology training programs and nephrology fellows answered the questions using an Internet-based questionnaire. During the live session, members of the audience tested their knowledge and judgment on a series of case-oriented questions prepared and discussed by the experts. They compared their answers in real time using audience response devices with the answers of the nephrology fellows and training program directors. The correct and incorrect answers were then discussed after the audience responses and the results of the questionnaire were displayed. As always, the audience, lecturers, and moderators enjoyed this educational session. This article recapitulates the acid-base and electrolyte disorders portion of the session and reproduces its educational value for the readers of the Clinical Journal of the American Society of Nephrology. Enjoy the clinical cases and expert discussions. Copyright © 2015 by the American Society of Nephrology.

  4. Using problem based learning and guided inquiry in a high school acid-base chemistry unit

    Science.gov (United States)

    McKinley, Katie

    The purpose of this investigation was to determine if incorporating problem based learning and guided inquiry would improve student achievement in an acid base unit for high school chemistry. The activities and labs in the unit were modified to be centered around the problem of a fish kill that students investigated. Students also participated in guided inquiry labs to increase the amount of critical thinking and problem solving being done in the classroom. The hypothesis was that the implementation of problem based learning and guided inquiry would foster student learning. Students took a pre-test and post-test on questions covering the objectives of the acid base unit. These assessments were compared to determine the effectiveness of the unit. The results indicate that the unit was effective in increasing student performance on the unit test. This study also analyzed the process of problem based learning. Problem based learning can be an effective method of engaging students in inquiry. However, designing an effective problem based learning unit requires careful design of the problem and enough structure to assure students learn the intended content.

  5. The generalized Lewis acid-base titration of palladium and niobium

    International Nuclear Information System (INIS)

    Cima, M.; Brewer, L.; California Univ., Berkeley, CA

    1988-01-01

    The high thermodynamic stability of alloys composed of platinum group metals and group IVB and VB metals has been explained by an electronic interaction analogous to the Lewis acid-base concept for nontransition elements. The analogy is further demonstrated by the titration of palladium by addition of niobium. The activity of niobium in solid palladium was measured as a function of concentration by solid-state galvanic cells and study of the ternary oxide phase diagram. The galvanic cells were of the Pt/NbO 2 , Nb 2 O 4.8 /YDT/NbO y , Nb (Pd) /Pt where the solid electrolyte is yttria-doped thoria (YDT). Ternary phase diagrams for the Pd-Nb-O and Rh-Nb-O systems were obtained by characterizing samples equilibrated at 1000 0 C. The phase relationships found in the ternary diagrams were also used to derive thermochemical data for the alloys. Thermochemical quantities for other acid-base stabilized alloys such as Nb-Rh, Ti-Pd, and Ti-Rh were also measured

  6. Spectroscopic study on variations in illite surface properties after acid-base titration.

    Science.gov (United States)

    Liu, Wen-xin; Coveney, R M; Tang, Hong-xiao

    2003-07-01

    FT-IR, Raman microscopy, XRD, 29Si and 27Al MAS NMR, were used to investigate changes in surface properties of a natural illite sample after acid-base potentiometric titration. The characteristic XRD lines indicated the presence of surface Al-Si complexes, preferable to Al(OH)3 precipitates. In the microscopic Raman spectra, the vibration peaks of Si-O and Al-O bonds diminished as a result of treatment with acid, then increased after hydroxide back titration. The varied ratio of signal intensity between (IV)Al and (VI)Al species in 27Al MAS NMR spectra, together with the stable BET surface area after acidimetric titration, suggested that edge faces and basal planes in the layer structure of illite participated in dissolution of structural components. The combined spectroscopic evidence demonstrated that the reactions between illite surfaces and acid-leaching silicic acid and aluminum ions should be considered in the model description of surface acid-base properties of the aqueous illite.

  7. Ammonia production from amino acid-based biomass-like sources by engineered Escherichia coli.

    Science.gov (United States)

    Mikami, Yosuke; Yoneda, Hisanari; Tatsukami, Yohei; Aoki, Wataru; Ueda, Mitsuyoshi

    2017-12-01

    The demand for ammonia is expected to increase in the future because of its importance in agriculture, industry, and hydrogen transportation. Although the Haber-Bosch process is known as an effective way to produce ammonia, the process is energy-intensive. Thus, an environmentally friendly ammonia production process is desired. In this study, we aimed to produce ammonia from amino acids and amino acid-based biomass-like resources by modifying the metabolism of Escherichia coli. By engineering metabolic flux to promote ammonia production using the overexpression of the ketoisovalerate decarboxylase gene (kivd), derived from Lactococcus lactis, ammonia production from amino acids was 351 mg/L (36.6% yield). Furthermore, we deleted the glnA gene, responsible for ammonia assimilation. Using yeast extract as the sole source of carbon and nitrogen, the resultant strain produced 458 mg/L of ammonia (47.8% yield) from an amino acid-based biomass-like material. The ammonia production yields obtained are the highest reported to date. This study suggests that it will be possible to produce ammonia from waste biomass in an environmentally friendly process.

  8. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review

    Directory of Open Access Journals (Sweden)

    Hartati Hartati

    2013-06-01

    Full Text Available This paper reviews various types of heterogeneous acid-base catalysts for fragrances preparation. Catalytic activities of various types of heterogeneous acid and base catalysts in fragrances preparation, i.e. non-zeolitic, zeolitic, and mesoporous molecular sieves have been reported. Generally, heterogeneous acid catalysts are commonly used in fragrance synthesis as compared to heterogeneous base catalysts. Heteropoly acids and hydrotalcites type catalysts are widely used as heterogeneous acid and base catalysts, respectively. © 2013 BCREC UNDIP. All rights reservedReceived: 20th January 2013; Revised: 31st March 2013; Accepted: 1st April 2013[How to Cite: Hartati, H., Santoso, M., Triwahyono, S., Prasetyoko, D. (2013. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 14-33. (doi:10.9767/bcrec.8.1.4394.14-33][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4394.14-33] | View in  |

  9. A review of the different techniques for solid surface acid-base characterization.

    Science.gov (United States)

    Sun, Chenhang; Berg, John C

    2003-09-18

    In this work, various techniques for solid surface acid-base (AB) characterization are reviewed. Different techniques employ different scales to rank acid-base properties. Based on the results from literature and the authors' own investigations for mineral oxides, these scales are compared. The comparison shows that Isoelectric Point (IEP), the most commonly used AB scale, is not a description of the absolute basicity or acidity of a surface, but a description of their relative strength. That is, a high IEP surface shows more basic functionality comparing with its acidic functionality, whereas a low IEP surface shows less basic functionality comparing with its acidic functionality. The choice of technique and scale for AB characterization depends on the specific application. For the cases in which the overall AB property is of interest, IEP (by electrokinetic titration) and H(0,max) (by indicator dye adsorption) are appropriate. For the cases in which the absolute AB property is of interest such as in the study of adhesion, it is more pertinent to use chemical shift (by XPS) and the heat of adsorption of probe gases (by calorimetry or IGC).

  10. AMINO ACID-BASED FERTILIZER AS AN ALTERNATIVE TO CALDA VIÇOSA IN ORGANIC AGRICULTURE

    Directory of Open Access Journals (Sweden)

    Diego Fontebasso Pelizari Pinto

    2017-10-01

    Full Text Available The aim of this study was to propose a mixture of micronutrients with amino acid-based foliar fertilizer as an alternative to calda viçosa for application in organic agriculture. The study was conducted in two simultaneous trials in an experimental field in Ipeúna, SP, Brazil. The test plant was carioca type dry edible bean cv. Pérola. The treatments in trial 1 were: Control 1 = water; FA = JK® amino acid-based foliar fertilizer; and FA+Mi = FA + CuSO4 + ZnSO4 + MnSO4 + H3BO3. In trial 2, the FA treatment was substituted by calda viçosa (CVi. The treatments were through spray application three times. Dry edible bean leaves were sampled for determination of macronutrient and micronutrient concentrations. Platings of the application rates used in the treatments were performed in the laboratory in a mixture with Bacillus thuringiensis and with Beauveria bassiana to compare the degree of compatibility by means of colony forming units (CFU. The FA+Mi and CVi treatments raised the concentrations of Zn, Cu, and Mn in the leaves. The FA+Mi was compatible, the FA was a stimulant, and the CVi was noxious to B. bassiana and to B. thuringiensis when integrated in the spray mixture.

  11. Acid-base synergistic flame retardant wood pulp paper with high thermal stability.

    Science.gov (United States)

    Wang, Ning; Liu, Yuansen; Xu, Changan; Liu, Yuan; Wang, Qi

    2017-12-15

    Acid-catalytic degradation caused by acid source flame retardants is the main reason for a decline in thermal stability of flame-retarded lignocellulosic materials. In the present research, a guanidine phosphate (GP)/borax (BX) flame retardant system based on acid-base synergistic interaction was designed and used in wood pulp paper (WPP) to solve this problem. Results showed that the treated WPP obtained good flame retardancy with a limiting oxygen index (LOI) value of 35.7%. As a basic flame retardant, borax could chemically combine with the acids released by guanidine phosphate, thus decreasing the acidity of the system in the initial heating stage. In this way, acid-catalytic degradation is greatly retarded on the lignocelluloses to improve thermal stability (the temperature of maximum degradation peak from 286°C to 314°C). Meanwhile, borax was also advantageous to form a denser and firmer condensed phase through reinforcement of the acid-base reaction product, borophosphates, allowing it to provide a protective barrier with higher quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Acid-base physiology, neurobiology and behaviour in relation to CO2-induced ocean acidification.

    Science.gov (United States)

    Tresguerres, Martin; Hamilton, Trevor J

    2017-06-15

    Experimental exposure to ocean and freshwater acidification affects the behaviour of multiple aquatic organisms in laboratory tests. One proposed cause involves an imbalance in plasma chloride and bicarbonate ion concentrations as a result of acid-base regulation, causing the reversal of ionic fluxes through GABA A receptors, which leads to altered neuronal function. This model is exclusively based on differential effects of the GABA A receptor antagonist gabazine on control animals and those exposed to elevated CO 2 However, direct measurements of actual chloride and bicarbonate concentrations in neurons and their extracellular fluids and of GABA A receptor properties in aquatic organisms are largely lacking. Similarly, very little is known about potential compensatory mechanisms, and about alternative mechanisms that might lead to ocean acidification-induced behavioural changes. This article reviews the current knowledge on acid-base physiology, neurobiology, pharmacology and behaviour in relation to marine CO 2 -induced acidification, and identifies important topics for future research that will help us to understand the potential effects of predicted levels of aquatic acidification on organisms. © 2017. Published by The Company of Biologists Ltd.

  13. Ferulic Acid-Based Polymers with Glycol Functionality as a Versatile Platform for Topical Applications.

    Science.gov (United States)

    Ouimet, Michelle A; Faig, Jonathan J; Yu, Weiling; Uhrich, Kathryn E

    2015-09-14

    Ferulic acid-based polymers with aliphatic linkages have been previously synthesized via solution polymerization methods, yet they feature relatively slow ferulic acid release rates (∼11 months to 100% completion). To achieve a more rapid release rate as required in skin care formulations, ferulic acid-based polymers with ethylene glycol linkers were prepared to increase hydrophilicity and, in turn, increase ferulic acid release rates. The polymers were characterized using nuclear magnetic resonance and Fourier transform infrared spectroscopies to confirm chemical composition. The molecular weights, thermal properties (e.g., glass transition temperature), and contact angles were also obtained and the polymers compared. Polymer glass transition temperature was observed to decrease with increasing linker molecule length, whereas increasing oxygen content decreased polymer contact angle. The polymers' chemical structures and physical properties were shown to influence ferulic acid release rates and antioxidant activity. In all polymers, ferulic acid release was achieved with no bioactive decomposition. These polymers demonstrate the ability to strategically release ferulic acid at rates and concentrations relevant for topical applications such as skin care products.

  14. Nutrient based estimation of acid-base balance in vegetarians and non-vegetarians.

    Science.gov (United States)

    Deriemaeker, Peter; Aerenhouts, Dirk; Hebbelinck, Marcel; Clarys, Peter

    2010-03-01

    A first objective of the present study was to estimate the acid-base balance of the food intake in vegetarians and non-vegetarians. A second objective was to evaluate if additional input of specific food items on the existing potential renal acid load (PRAL) list was necessary for the comparison of the two dietary patterns. Thirty vegetarians between the age of 18 and 30 years were matched for sex, age and BMI with 30 non-vegetarians. Based on the 3-days food diaries the acid-base status of the food intake was estimated using the PRAL method. Mean PRAL values as estimated with the standard table yielded an alkaline load of -5.4 +/- 14.4 mEq/d in the vegetarians compared to an acid load of 10.3 +/- 14.4 mEq/d in the nonvegetarians (pvegetarians compared to an acid load of 13.8 +/- 17.1 mEq/d for the non-vegetarians (pvegetarian food intake produces more alkaline outcomes compared to non-vegetarian diets. The use of the standard PRAL table was sufficient for discrimination between the two diets.

  15. Pulmonary histopathologic findings, acid-base status, and absorption of colostral immunoglobulins in newborn calves.

    Science.gov (United States)

    López, A; Löfstedt, J; Bildfell, R; Horney, B; Burton, S

    1994-09-01

    A study was conducted to investigate whether aspiration of amniotic fluid is associated with a deleterious effect on absorption of colostral immunoglobulins or on blood gas and acid-base values of healthy newborn calves. Fourteen calves purchased from commercial sources were transported to a research facility immediately after birth and fed colostrum with known concentrations of immunoglobulins. Blood samples for gas analyses were collected within 5 hours of birth, 24 hours later, and prior to euthanasia. Between 3 and 5 days of age, calves were euthanatized by an overdose of barbiturates. Eleven calves had evidence of bronchoaspiration of amniotic fluid, as determined by presence of meconium, squamous epithelium, or keratin in histologic sections of fixed lung or by cytologic analysis of bronchoalveolar lavage fluid. Blood gas tensions and pH were within reference ranges in 11 of 14 calves. Aspiration of amniotic fluid could not be linked to any specific changes in blood gas tensions, acid-base status, or absorption of colostral immunoglobulins. Presence of keratin and meconium in the lungs often was accompanied by mild exudative alveolitis and focal atelectasis. It was concluded that aspiration of small amounts of amniotic fluid with or without meconium is common in calves and is not associated with hypoxemia, respiratory acidosis, or failure of passive transfer.

  16. Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media.

    Science.gov (United States)

    Popović, Gordana; Cakar, Mira; Agbaba, Danica

    2009-01-15

    Acid-base equilibria in homogeneous and heterogeneous systems of two antihistaminics, loratadine and desloratadine were studied spectrophotometrically in Britton-Robinson's buffer at 25 degrees C. Acidity constant of loratadine was found to be pK(a) 5.25 and those of desloratadine pK(a1) 4.41 and pK(a2) 9.97. The values of intrinsic solubilities of loratadine and desloratadine were 8.65x10(-6) M and 3.82x10(-4) M, respectively. Based on the pK(a) values and intrinsic solubilities, solubility curves of these two drugs as a function of pH were calculated. The effects of anionic, cationic and non-ionic surfactants applied in the concentration exceeding critical micelle concentration (cmc) on acid-base properties of loratadine and desloratadine, as well as on intrinsic solubility of loratadine were also examined. The results revealed a shift of pK(a) values in micellar media comparing to the values obtained in water. These shifts (DeltapK(a)) ranged from -2.24 to +1.24.

  17. An Exact Method to Determine the Conductivity of Aqueous Solutions in Acid-Base Titrations

    Directory of Open Access Journals (Sweden)

    Norma Rodríguez-Laguna

    2015-01-01

    Full Text Available Several works in the literature show that it is possible to establish the analytic equations to estimate the volume V of a strong base or a strong acid (Vb and Va, resp. being added to a solution of a substance or a mix of substances during an acid-base titration, as well as the equations to estimate the first derivative of the titration plot dpH/dV, and algebraic expressions to determine the buffer β capacity with dilution βdil. This treatment allows establishing the conditions of thermodynamic equilibria for all species within a system containing a mix of species from one or from various polyacid systems. The present work shows that it is possible to determine exactly the electric conductivity of aqueous solutions for these Brønsted acid-base titrations, because the functional relation between this property and the composition of the system in equilibrium is well known; this is achieved using the equivalent conductivity λi values of each of the ions present in a given system. The model employed for the present work confirms the experimental outcomes with the H2SO4, B(OH3, CH3COOH, and H3PO4 aqueous solutions’ titration.

  18. Effect of temperature on acid-base equilibria in separation techniques. A review.

    Science.gov (United States)

    Gagliardi, Leonardo G; Tascon, Marcos; Castells, Cecilia B

    2015-08-19

    Studies on the theoretical principles of acid-base equilibria are reviewed and the influence of temperature on secondary chemical equilibria within the context of separation techniques, in water and also in aqueous-organic solvent mixtures, is discussed. In order to define the relationships between the retention in liquid chromatography or the migration velocity in capillary electrophoresis and temperature, the main properties of acid-base equilibria have to be taken into account for both, the analytes and the conjugate pairs chosen to control the solution pH. The focus of this review is based on liquid-liquid extraction (LLE), liquid chromatography (LC) and capillary electrophoresis (CE), with emphasis on the use of temperature as a useful variable to modify selectivity on a predictable basis. Simplified models were evaluated to achieve practical optimizations involving pH and temperature (in LLE and CE) as well as solvent composition in reversed-phase LC. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Modelling of the acid base properties of two thermophilic bacteria at different growth times

    Science.gov (United States)

    Heinrich, Hannah T. M.; Bremer, Phil J.; McQuillan, A. James; Daughney, Christopher J.

    2008-09-01

    Acid-base titrations and electrophoretic mobility measurements were conducted on the thermophilic bacteria Anoxybacillus flavithermus and Geobacillus stearothermophilus at two different growth times corresponding to exponential and stationary/death phase. The data showed significant differences between the two investigated growth times for both bacterial species. In stationary/death phase samples, cells were disrupted and their buffering capacity was lower than that of exponential phase cells. For G. stearothermophilus the electrophoretic mobility profiles changed dramatically. Chemical equilibrium models were developed to simultaneously describe the data from the titrations and the electrophoretic mobility measurements. A simple approach was developed to determine confidence intervals for the overall variance between the model and the experimental data, in order to identify statistically significant changes in model fit and thereby select the simplest model that was able to adequately describe each data set. Exponential phase cells of the investigated thermophiles had a higher total site concentration than the average found for mesophilic bacteria (based on a previously published generalised model for the acid-base behaviour of mesophiles), whereas the opposite was true for cells in stationary/death phase. The results of this study indicate that growth phase is an important parameter that can affect ion binding by bacteria, that growth phase should be considered when developing or employing chemical models for bacteria-bearing systems.

  20. Amino acid-based zwitterionic polymers: antifouling properties and low cytotoxicity.

    Science.gov (United States)

    Li, Wenchen; Liu, Qingsheng; Liu, Lingyun

    2014-01-01

    A group of five amino acid containing zwitterionic vinyl monomers, based on serine, lysine, ornithine, glutamic acid, and aspartic acid, respectively, were proposed and developed for potential antifouling applications. Their polymer brushes were grafted on gold chips by surface-initiated photoiniferter-mediated polymerization. We then compared their performance in resisting protein adsorption from full human serum and plasma. All five polymers can reduce protein adsorption by more than 90% compared to the unmodified gold. The ornithine-based and aspartic acid-based poly(methacrylamide) can most strongly resist protein adsorption from serum and plasma, compared to the other three. The ability of surfaces to suppress bacterial adhesion is another criterion in evaluating antifouling properties of materials. Our results show that the five polymer-grafted surfaces can significantly suppress Escherichia coli K12 adhesion to 99% compared to the bare gold surface. The zwitterionic structure of amino acids, with homogenously distributed and balanced positive and negative charges, is responsible for the outstanding antifouling properties. Considering multiple potential applications (e.g. medical devices and drug delivery) of the antifouling materials, we further systematically evaluated the cytotoxicity of both monomers and polymer nanogels for all five materials at various concentrations. Very low cytotoxicity was observed for all tested amino acid-based monomers and nanogels, which is comparable or even lower than the traditional and some newly developed antifouling materials, which might be related to the biomimetic nature of amino acids.

  1. Coefficient of Friction Between Carboxymethylated Hyaluronic Acid-Based Polymer Films and the Ocular Surface.

    Science.gov (United States)

    Colter, Jourdan; Wirostko, Barbara; Coats, Brittany

    2017-12-01

    Hyaluronic acid-based polymer films are emerging as drug-delivery vehicles for local and continuous drug administration to the eye. The highly lubricating hyaluronic acid increases comfort, but displaces films from the eye, reducing drug exposure and efficacy. Previous studies have shown that careful control of the surface interaction of the film with the eye is critical for improved retention. In this study, the frictional interaction of a carboxymethylated, hyaluronic acid-based polymer (CMHA-S) with and without methylcellulose was quantified against ovine and human sclera at three axial loads (0.3, 0.5, and 0.7 N) and four sliding velocities (0.3, 1.0, 10, and 30 mm/s). Static coefficients of friction significantly increased with rate (P Friction became more rate-dependent when methylcellulose was added to CMHA-S. Kinetic coefficient of friction was not affected by rate, and averaged 0.15 ± 0.1. Methylcellulose increased CMHA-S static and kinetic friction by 60% and 80%, respectively, but was also prone to wear during testing. These data suggest that methylcellulose can be used to create a friction differential on the film, but a potentially increased degradation rate with the methylcellulose must be considered in the design.

  2. The glmS Ribozyme Cofactor is a General Acid-Base Catalyst

    Science.gov (United States)

    Viladoms, Julia; Fedor, Martha J.

    2012-01-01

    The glmS ribozyme is the first natural self-cleaving ribozyme known to require a cofactor. The D-glucosamine-6-phosphate (GlcN6P) cofactor has been proposed to serve as a general acid, but its role in the catalytic mechanism has not been established conclusively. We surveyed GlcN6P-like molecules for their ability to support self-cleavage of the glmS ribozyme and found a strong correlation between the pH dependence of the cleavage reaction and the intrinsic acidity of the cofactors. For cofactors with low binding affinities the contribution to rate enhancement was proportional to their intrinsic acidity. This linear free-energy relationship between cofactor efficiency and acid dissociation constants is consistent with a mechanism in which the cofactors participate directly in the reaction as general acid-base catalysts. A high value for the Brønsted coefficient (β ~ 0.7) indicates that a significant amount of proton transfer has already occurred in the transition state. The glmS ribozyme is the first self-cleaving RNA to use an exogenous acid-base catalyst. PMID:23113700

  3. The glmS ribozyme cofactor is a general acid-base catalyst.

    Science.gov (United States)

    Viladoms, Júlia; Fedor, Martha J

    2012-11-21

    The glmS ribozyme is the first natural self-cleaving ribozyme known to require a cofactor. The d-glucosamine-6-phosphate (GlcN6P) cofactor has been proposed to serve as a general acid, but its role in the catalytic mechanism has not been established conclusively. We surveyed GlcN6P-like molecules for their ability to support self-cleavage of the glmS ribozyme and found a strong correlation between the pH dependence of the cleavage reaction and the intrinsic acidity of the cofactors. For cofactors with low binding affinities, the contribution to rate enhancement was proportional to their intrinsic acidity. This linear free-energy relationship between cofactor efficiency and acid dissociation constants is consistent with a mechanism in which the cofactors participate directly in the reaction as general acid-base catalysts. A high value for the Brønsted coefficient (β ~ 0.7) indicates that a significant amount of proton transfer has already occurred in the transition state. The glmS ribozyme is the first self-cleaving RNA to use an exogenous acid-base catalyst.

  4. Effect of Gamma Radiation on Amino Acid Based Vesicle Carrying Radiosensitizer

    International Nuclear Information System (INIS)

    Nur Ratasha Alia Mohd Rosli; Faizal Mohamed; Muhammad Amir Syafiq Mohd Sah; Irman Abdul Rahman

    2014-01-01

    Vesicles has been developed and studied to be used as a medium to transport radiosensitizer in treating cancer cells by increasing its sensitivity effectively towards the radiation given during radiotherapy. This study was conducted to investigate the effect of gamma radiation on amino acid-based vesicle carrying radiosensitizer. Amino acid based vesicles carrying radiosensitizer were synthesized using sonication method with sodium N-lauroylsarcosinate hydrate and decanol being the primary surfactant, while hydrogen peroxide and sodium hyaluronate as the encapsulated radiosensitizer. The synthesized vesicle was then irradiated at radiation doses equivalent to those given during radiotherapy. Irradiated vesicle carrying radiosensitizer were then characterized using Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR) and Polarized Light Microscope. Results obtained shows that there were no significant changes in morphology and molecular conformation of the synthesized vesicle after irradiation. Even at higher radiation dose of 100 Gray and 200 Gray, the results remained unchanged. This indicates that the synthesized vesicle carrying radiosensitizer is morphologically and spectroscopically stable even at high radiation doses. (author)

  5. A Prebiotic Chemistry Experiment on the Adsorption of Nucleic Acids Bases onto a Natural Zeolite.

    Science.gov (United States)

    Anizelli, Pedro R; Baú, João Paulo T; Gomes, Frederico P; da Costa, Antonio Carlos S; Carneiro, Cristine E A; Zaia, Cássia Thaïs B V; Zaia, Dimas A M

    2015-09-01

    There are currently few mechanisms that can explain how nucleic acid bases were synthesized, concentrated from dilute solutions, and/or protected against degradation by UV radiation or hydrolysis on the prebiotic Earth. A natural zeolite exhibited the potential to adsorb adenine, cytosine, thymine, and uracil over a range of pH, with greater adsorption of adenine and cytosine at acidic pH. Adsorption of all nucleic acid bases was decreased in artificial seawater compared to water, likely due to cation complexation. Furthermore, adsorption of adenine appeared to protect natural zeolite from thermal degradation. The C=O groups from thymine, cytosine and uracil appeared to assist the dissolution of the mineral while the NH2 group from adenine had no effect. As shown by FT-IR spectroscopy, adenine interacted with a natural zeolite through the NH2 group, and cytosine through the C=O group. A pseudo-second-order model best described the kinetics of adenine adsorption, which occurred faster in artificial seawaters.

  6. On-line hemodiafiltration with pre- and postdilution: impact on the acid-base status.

    Science.gov (United States)

    Ahrenholz, P; Winkler, R E; Ramlow, W; Tiess, M; Thews, O

    1998-06-01

    With on-line formation of the substitution fluid, high substitution rates in predilution (PRD) and postdilution (POD) can be obtained (Fresenius 4008 On-Line HDF; Gambro AK 100 Ultra). The substitution fluid is branched off from the dialysate produced by the dialysate delivery system of the HDF machine. Under these conditions it is desirable to consider the effect of the different treatment modes on the acid-base status. Using Fresenius 4008 On-Line HDF machines, ESRD-patients were treated alternately with high-flux hemodialysis (HD), postdilution HDF (POD-HDF) and predilution HDF (PRD-HDF), while all other treatment parameters were kept constant, in particular the bicarbonate dialysate concentration. Plasma-HCO3, -pH and -pCO2 were measured and compared with the results of a multicompartment bicarbonate model developed by Thews. Also plasma-pO2 and K+ were measured. The results showed no significant differences between HD, POD- and PRD-HDF. Acidosis was corrected effectively and no excessive compensation of the acid-base disturbance was observed.

  7. Opportunity integrated assessment facilitating critical thinking and science process skills measurement on acid base matter

    Science.gov (United States)

    Sari, Anggi Ristiyana Puspita; Suyanta, LFX, Endang Widjajanti; Rohaeti, Eli

    2017-05-01

    Recognizing the importance of the development of critical thinking and science process skills, the instrument should give attention to the characteristics of chemistry. Therefore, constructing an accurate instrument for measuring those skills is important. However, the integrated instrument assessment is limited in number. The purpose of this study is to validate an integrated assessment instrument for measuring students' critical thinking and science process skills on acid base matter. The development model of the test instrument adapted McIntire model. The sample consisted of 392 second grade high school students in the academic year of 2015/2016 in Yogyakarta. Exploratory Factor Analysis (EFA) was conducted to explore construct validity, whereas content validity was substantiated by Aiken's formula. The result shows that the KMO test is 0.714 which indicates sufficient items for each factor and the Bartlett test is significant (a significance value of less than 0.05). Furthermore, content validity coefficient which is based on 8 experts is obtained at 0.85. The findings support the integrated assessment instrument to measure critical thinking and science process skills on acid base matter.

  8. Two Dimensional Multiwavelength Fluorescence Spectra of Dipicolinic Acid and Calcium Dipicolinate

    National Research Council Canada - National Science Library

    Sarasanandarajah, Sivananthan

    2004-01-01

    .... In this paper we report in some detail on the room temperature fluorescence excitation and emission spectra of DPA and its calcium ion complex and comparison of the excitation-emission spectrum...

  9. Novel sulfonated poly (ether ether keton)/polyetherimide acid-base blend membranes for vanadium redox flow battery applications

    International Nuclear Information System (INIS)

    Liu, Shuai; Wang, Lihua; Ding, Yue; Liu, Biqian; Han, Xutong; Song, Yanlin

    2014-01-01

    Highlights: • SPEEK/PEI acid-base blend membranes are prepared for VRB applications. • The acid-base blend membranes have much lower vanadium ion permeability. • The energy efficiency of SPEEK/PEI maintain around 86.9% after 50 cycles. - Abstract: Novel acid-base blend membranes composed of sulfonated poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared for vanadium redox flow battery (VRB). The blend membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electronic microscopy (SEM). The ion exchange capacity (IEC), proton conductivity, water uptake, vanadium ion permeability and mechanical properties were measured. As a result, the acid-base blend membranes exhibit higher water uptake, IEC and lower vanadium ion permeability compared to Nafion117 membranes and all these properties decrease with the increase of PEI. In VRB single cell test, the VRB with blend membranes shows lower charge capacity loss, higher coulombic efficiency (CE) and energy efficiency (EE) than Nafion117 membrane. Furthermore, the acid-base blend membranes present stable performance up to 50 cycles with no significant decline in CE and EE. All experimental results indicate that the SPEEK/PEI (S/P) acid-base blend membranes show promising prospects for VRB

  10. Adsorption of amino acids and nucleic acid bases onto minerals: a few suggestions for prebiotic chemistry experiments

    Science.gov (United States)

    Zaia, Dimas A. M.

    2012-10-01

    Amino acids and nucleic acid bases are very important for the living organisms. Thus, their protection from decomposition, selection, pre-concentration and formation of biopolymers are important issues for understanding the origin of life on the Earth. Minerals could have played all of these roles. This paper discusses several aspects involving the adsorption of amino acids and nucleic acid bases onto minerals under conditions that could have been found on the prebiotic Earth; in particular, we recommend the use of minerals, amino acids, nucleic acid bases and seawater ions in prebiotic chemistry experiments. Several experiments involving amino acids, nucleic acid bases, minerals and seawater ions are also suggested, including: (a) using well-characterized minerals and the standardization of the mineral synthesis methods; (b) using primary chondrite minerals (olivine, pyroxene, etc.) and clays modified with metals (Cu, Fe, Ni, Mo, Zn, etc.); (c) determination of the possible products of decomposition due to interactions of amino acids and nucleic acid bases with minerals; (d) using minerals with more organophilic characteristics; (e) using seawaters with different concentrations of ions (i.e. Na+, Ca2+, Mg2+, SO4 2- and Cl-) (f) using non-protein amino acids (AIB, α-ABA, β-ABA, γ-ABA and β-Ala and g) using nucleic acid bases other than adenine, thymine, uracil and cytosine. These experiments could be useful to clarify the role played by minerals in the origin of life on the Earth.

  11. Acid-base balance and hydration status following consumption of mineral-based alkaline bottled water

    Directory of Open Access Journals (Sweden)

    Heil Daniel P

    2010-09-01

    Full Text Available Abstract Background The present study sought to determine whether the consumption of a mineral-rich alkalizing (AK bottled water could improve both acid-base balance and hydration status in young healthy adults under free-living conditions. The AK water contains a naturally high mineral content along with Alka-PlexLiquid™, a dissolved supplement that increases the mineral content and gives the water an alkalizing pH of 10.0. Methods Thirty-eight subjects were matched by gender and self-reported physical activity (SRPA, hrs/week and then split into Control (12 women, 7 men; Mean +/- SD: 23 +/- 2 yrs; 7.2 +/- 3.6 hrs/week SRPA and Experimental (13 women, 6 men; 22 +/- 2 yrs; 6.4 +/- 4.0 hrs/week SRPA groups. The Control group consumed non-mineralized placebo bottled water over a 4-week period while the Experimental group consumed the placebo water during the 1st and 4th weeks and the AK water during the middle 2-week treatment period. Fingertip blood and 24-hour urine samples were collected three times each week for subsequent measures of blood and urine osmolality and pH, as well as total urine volume. Dependent variables were analyzed using multivariate repeated measures ANOVA with post-hoc focused on evaluating changes over time within Control and Experimental groups (alpha = 0.05. Results There were no significant changes in any of the dependent variables for the Control group. The Experimental group, however, showed significant increases in both the blood and urine pH (6.23 to 7.07 and 7.52 to 7.69, respectively, a decreased blood and increased urine osmolality, and a decreased urine output (2.51 to 2.05 L/day, all during the second week of the treatment period (P Conclusions Consumption of AK water was associated with improved acid-base balance (i.e., an alkalization of the blood and urine and hydration status when consumed under free-living conditions. In contrast, subjects who consumed the placebo bottled water showed no changes over the

  12. Acid-base behavior in hydrothermal processing of wastes. 1997 annual progress report

    International Nuclear Information System (INIS)

    1997-01-01

    'A major obstacle to the development of hydrothermal technology for treating DOE wastes has been a lack of scientific knowledge of solution chemistry, thermodynamics and transport phenomena. The progress over the last year is highlighted in the following four abstracts from manuscripts which have been submitted to journals. The authors also have made considerable progress on a spectroscopic study of the acid-base equilibria of Cr(VI). They have utilized novel spectroscopic indicators to study acid-base equilibria up to 380 C. Until now, very few systems have been studied at such high temperatures, although this information is vital for hydrothermal processing of wastes. The pH values of aqueous solutions of boric acid and KOH were measured with the optical indicator 2-naphthol at temperatures from 300 to 380 C. The equilibrium constant Kb-l for the reaction B(OH)3 + OH - = B(OH) -4 was determined from the pH measurements and correlated with a modified Born model. The titration curve for the addition of HCl to sodium borate exhibits strong acid-strong base behavior even at 350 C and 24.1 MPa. At these conditions, aqueous solutions of sodium borate buffer the pH at 9.6 t 0.25. submitted to Ind. Eng. Chem. Res. Acetic Acid and HCl Acid-base titrations for the KOH-acetic acid or NH 3 -acetic acid systems were monitored with the optical indicator 2-naphthoic acid at 350 C and 34 MPa, and those for the HCl;Cl- system with acridine at 380 C and up to 34 MPa (5,000 psia ). KOH remains a much stronger base than NH,OH at high temperature. From 298 K to the critical temperature of water, the dissociation constant for HCl decreases by 13 orders of magnitude, and thus, the basicity of Cl - becomes significant. Consequently, the addition of NaCl to HCl raises the pH. The pH titration curves may be predicted with reasonable accuracy from the relevant equilibrium constants and Pitzer''s formulation of the Debye- Htickel equation for the activity coefficients.'

  13. Hypoxia and Its Acid-Base Consequences: From Mountains to Malignancy.

    Science.gov (United States)

    Swenson, Erik R

    Hypoxia, depending upon its magnitude and circumstances, evokes a spectrum of mild to severe acid-base changes ranging from alkalosis to acidosis, which can alter many responses to hypoxia at both non-genomic and genomic levels, in part via altered hypoxia-inducible factor (HIF) metabolism. Healthy people at high altitude and persons hyperventilating to non-hypoxic stimuli can become alkalotic and alkalemic with arterial pH acutely rising as high as 7.7. Hypoxia-mediated respiratory alkalosis reduces sympathetic tone, blunts hypoxic pulmonary vasoconstriction and hypoxic cerebral vasodilation, and increases hemoglobin oxygen affinity. These effects and others can be salutary or counterproductive to tissue oxygen delivery and utilization, based upon magnitude of each effect and summation. With severe hypoxia either in the setting of profound arterial hemoglobin desaturation and reduced O2 content or poor perfusion (ischemia) at the global or local level, metabolic and hypercapnic acidosis develop along with considerable lactate formation and pH falling to below 6.8. Although conventionally considered to be injurious and deleterious to cell function and survival, both acidoses may be cytoprotective by various anti-inflammatory, antioxidant, and anti-apoptotic mechanisms which limit total hypoxic or ischemic-reperfusion injury. Attempts to correct acidosis by giving bicarbonate or other alkaline agents under these circumstances ahead of or concurrent with reoxygenation efforts may be ill advised. Better understanding of this so-called "pH paradox" or permissive acidosis may offer therapeutic possibilities. Rapidly growing cancers often outstrip their vascular supply compromising both oxygen and nutrient delivery and metabolic waste disposal, thus limiting their growth and metastatic potential. However, their excessive glycolysis and lactate formation may not necessarily represent oxygen insufficiency, but rather the Warburg effect-an attempt to provide a large amount

  14. Correlation of Etest and Neo-Sensitabs diffusion assays on Mueller-Hinton-methylene blue agar with broth microdilution reference method (CLSI-M27-A2) for testing susceptibilities of Cryptococcus neoformans to amphotericin B and fluconazole.

    Science.gov (United States)

    Ochiuzzi, Maria Eugenia; Santiso, Gabriela María; Arechavala, Alicia Irene

    2010-09-01

    Cryptococcus neoformans causes disseminated infection in 7-8% of HIV positive patients admitted to Hospital F. J. Muñiz in Buenos Aires. Meningoencephalitis is the most frequent clinical manifestation and is one of the main causes of death in those patients with AIDS. The standard treatment for this mycosis consists of amphotericin B followed by fluconazole until two successive cultures of CFS are negative. Although resistance to these drugs is infrequent, minimal inhibitory concentrations (MIC) of some antifungals can be high. Since it is important to know the susceptibility levels of this fungus to the antifungal drugs usually employed in our institution, we analyzed the susceptibility test results of C. neoformans with two diffusion methods (Etest and NeoSensitabs tablets) employing Mueller-Hinton agar with 2% glucose and 0.5 microg/ml methylene blue. These results were compared with MICs obtained through the use of the broth microdilution reference method (CLSI). Results showed good agreement with the reference method, with no very major errors and only two major errors for fluconazole using NeoSensitabs tablets. For all the above mentioned, we confirm the usefulness of Mueller-Hinton agar to evaluate C. neoformans susceptibility to amphotericin B and fluconazole with these two agar diffusion methods.

  15. Novel Blend Membranes Based on Acid-Base Interactions for Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yongzhu Fu

    2012-10-01

    Full Text Available Fuel cells hold great promise for wide applications in portable, residential, and large-scale power supplies. For low temperature fuel cells, such as the proton exchange membrane fuel cells (PEMFCs and direct methanol fuel cells (DMFCs, proton-exchange membranes (PEMs are a key component determining the fuel cells performance. PEMs with high proton conductivity under anhydrous conditions can allow PEMFCs to be operated above 100 °C, enabling use of hydrogen fuels with high-CO contents and improving the electrocatalytic activity. PEMs with high proton conductivity and low methanol crossover are critical for lowering catalyst loadings at the cathode and improving the performance and long-term stability of DMFCs. This review provides a summary of a number of novel acid-base blend membranes consisting of an acidic polymer and a basic compound containing N-heterocycle groups, which are promising for PEMFCs and DMFCs.

  16. Wang-Landau Reaction Ensemble Method: Simulation of Weak Polyelectrolytes and General Acid-Base Reactions.

    Science.gov (United States)

    Landsgesell, Jonas; Holm, Christian; Smiatek, Jens

    2017-02-14

    We present a novel method for the study of weak polyelectrolytes and general acid-base reactions in molecular dynamics and Monte Carlo simulations. The approach combines the advantages of the reaction ensemble and the Wang-Landau sampling method. Deprotonation and protonation reactions are simulated explicitly with the help of the reaction ensemble method, while the accurate sampling of the corresponding phase space is achieved by the Wang-Landau approach. The combination of both techniques provides a sufficient statistical accuracy such that meaningful estimates for the density of states and the partition sum can be obtained. With regard to these estimates, several thermodynamic observables like the heat capacity or reaction free energies can be calculated. We demonstrate that the computation times for the calculation of titration curves with a high statistical accuracy can be significantly decreased when compared to the original reaction ensemble method. The applicability of our approach is validated by the study of weak polyelectrolytes and their thermodynamic properties.

  17. NABTIT-a computer program for non-aqueous acid-base titration.

    Science.gov (United States)

    Budevsky, O; Zikolova, T; Tencheva, J

    1988-11-01

    A program NABTIT written in BASIC has been developed for the treatment of data (ml/mV) obtained from potentiometric acid-base titrations in non-aqueous solvents. No preliminary information on equilibrium constants is required for the input. The treatment of the data is based on known equations and uses least-squares procedures. The essence of the method is to determine the equivalence volume (V(e)) accurately, and to use the data acquired by adding titrant after V(e) for the pH*-calibration of the non-aqueous potentiometric cell. As a by-product or the calculations, the pK* value of the substance titrated is also obtained, and in some cases the autoprotolysis constant of the medium (pK*(s)). Good agreement between experiment and theory was found in the treatment of data obtained for water and methanol-water mixtures.

  18. Chromophore Structure of Photochromic Fluorescent Protein Dronpa: Acid-Base Equilibrium of Two Cis Configurations.

    Science.gov (United States)

    Higashino, Asuka; Mizuno, Misao; Mizutani, Yasuhisa

    2016-04-07

    Dronpa is a novel photochromic fluorescent protein that exhibits fast response to light. The present article is the first report of the resonance and preresonance Raman spectra of Dronpa. We used the intensity and frequency of Raman bands to determine the structure of the Dronpa chromophore in two thermally stable photochromic states. The acid-base equilibrium in one photochromic state was observed by spectroscopic pH titration. The Raman spectra revealed that the chromophore in this state shows a protonation/deprotonation transition with a pKa of 5.2 ± 0.3 and maintains the cis configuration. The observed resonance Raman bands showed that the other photochromic state of the chromophore is in a trans configuration. The results demonstrate that Raman bands selectively enhanced for the chromophore yield valuable information on the molecular structure of the chromophore in photochromic fluorescent proteins after careful elimination of the fluorescence background.

  19. Features of Porous Anodic Alumina Growth in Galvanostatic Regime in Selenic Acid Based Electrolyte

    International Nuclear Information System (INIS)

    Nazarkina, Y.; Kamnev, K.; Dronov, A.; Dudin, A.; Pavlov, A.; Gavrilov, S.

    2017-01-01

    The features of porous anodic Al 2 O 3 formation process in galvanostatic regime in selenic acid based electrolyte under a range of anodization conditions were investigated. The growth process kinetics of porous anodic Al 2 O 3 was characterized by chronopotentiometric curves. The effect of electrolyte concentration, current density and anodization duration on the oxide porous structure ordering was studied by scanning electron microscopy. Approximate regions of self-ordered porous Al 2 O 3 formation process conditions were estimated. It was found that anodization parameters, at which self-ordered porous structure formation is observed, correspond to the conditions of equilibrium of oxidation and etching rates. It is shown that deviations from these conditions lead to the disordering of the porous structure.

  20. A Concentrated Hydrochloric Acid-based Method for Complete Recovery of DNA from Bone.

    Science.gov (United States)

    Huynen, Leon; Lambert, David M

    2015-11-01

    The successful extraction of DNA from historical or ancient animal bone is important for the analysis of discriminating genetic markers. Methods used currently rely on the digestion of bone with EDTA and proteinase K, followed by purification with phenol/chloroform and silica bed binding. We have developed a simple concentrated hydrochloric acid-based method that precludes the use of phenol/chloroform purification and can lead to a several-fold increase in DNA yield when compared to other commonly used methods. Concentrated hydrochloric acid was shown to dissolve most of the undigested bone and allowed the efficient recovery of DNA fragments <100 bases in length. This method should prove useful for the recovery of DNAs from highly degraded animal bone, such as that found in historical or ancient samples. © 2015 American Academy of Forensic Sciences.

  1. Second harmonic study of acid-base equilibrium at gold nanoparticle/aqueous interface

    Science.gov (United States)

    Ma, Jianqiang; Mandal, Sarthak; Bronsther, Corin; Gao, Zhenghan; Eisenthal, Kenneth B.

    2017-09-01

    Interfacial acid-base equilibrium of the capping molecules is a key factor to stabilize gold nanoparticles (AuNP) in solution. In this study we used Second Harmonic (SH) generation to measure interfacial potential and obtained a surface pKa value of 3.3 ± 0.1 for the carboxyl group in mercaptoundecanoic acid (MUA) molecule at an AuNP/aqueous interface. This pKa value is smaller than its bulk counterpart and indicates that the charged carboxylate group is favored at the AuNP surface. The SH findings are consistent with the effects of the noble metal (gold) surface on a charge in solution, as predicted by the method of images.

  2. Acid-base and coordination properties of Meso-substituted porphyrins in nonaqueous solutions

    Science.gov (United States)

    Pukhovskaya, S. G.; Nam, Dao Tkhe; Fien, Chan Ding; Domanina, E. N.; Ivanova, Yu. B.; Semeikin, A. S.

    2017-09-01

    Acid-base and coordination properties of alkyl and aryl meso-substituted porphyrins are studied spectrophotometrically in nonaqueous solutions. It is found that the nature of the substituent greatly affects the basicity of ligands for porphyrins characterized by a flat structure of macrocycle. The electronic effects of substituents have a much weaker influence on the kinetics of complexing. These effects could be due to the opposite orientation of some factors: an increase in the basicity and stability of the N-H bonds of porphyrin reaction centers. Dissociation constants p K b of the cationic forms of meso-substituted derivatives of porphyrin are measured. The values of p K b are in good agreement with classic concepts of the nature of substituents, particularly those indirectly included in the macrocycle through phenyl buffer rings.

  3. Post-hypercapnia recovery in the dog: arterial blood acid-base equilibrium and glycolysis.

    Science.gov (United States)

    Saunier, C; Horsky, P; Hannhart, B; Garcia-Carmona, T; Hartemann, D

    1977-12-01

    Changes in acid-base equilibrium and blood lactate and pyruvate concentrations were studied during recovery (breathing room air) after three days hypercapnia (FICO2 = 0.10) in awake dogs. Fast return to FICO2 = 0 produced a slight alkalosis in arterial blood and an increase in lactate and pyruvate concentrations which seemed to be maximum at the 15th minute. These changes were inhibited by previous injection of acetazolamide (50 mg/kg body weight). During progressive return to FICO2 = 0, over 1 hour, the peak value of blood lactate and pyruvate was delayed until the end of that hour, at the same time as a slight blood alkalosis appeared. These phenomen are most probably explained by a stimulation, due to alkalosis, of glycolysis at the level of phosphofructokinase.

  4. Acid-base chemical reaction model for nucleation rates in the polluted atmospheric boundary layer.

    Science.gov (United States)

    Chen, Modi; Titcombe, Mari; Jiang, Jingkun; Jen, Coty; Kuang, Chongai; Fischer, Marc L; Eisele, Fred L; Siepmann, J Ilja; Hanson, David R; Zhao, Jun; McMurry, Peter H

    2012-11-13

    Climate models show that particles formed by nucleation can affect cloud cover and, therefore, the earth's radiation budget. Measurements worldwide show that nucleation rates in the atmospheric boundary layer are positively correlated with concentrations of sulfuric acid vapor. However, current nucleation theories do not correctly predict either the observed nucleation rates or their functional dependence on sulfuric acid concentrations. This paper develops an alternative approach for modeling nucleation rates, based on a sequence of acid-base reactions. The model uses empirical estimates of sulfuric acid evaporation rates obtained from new measurements of neutral molecular clusters. The model predicts that nucleation rates equal the sulfuric acid vapor collision rate times a prefactor that is less than unity and that depends on the concentrations of basic gaseous compounds and preexisting particles. Predicted nucleation rates and their dependence on sulfuric acid vapor concentrations are in reasonable agreement with measurements from Mexico City and Atlanta.

  5. A perspective: photosynthetic production of fatty acid-based biofuels in genetically engineered cyanobacteria.

    Science.gov (United States)

    Lu, Xuefeng

    2010-01-01

    Biofuels are expected to play a key role in the development of a sustainable, economical and environmentally safe source of energy. Microbes offer great potential for applications in technology based biofuel production. Three fundamental questions need to be addressed in order for the development of microbial synthesis of biofuels to be successful. Firstly, what energy resource platform could be used to make biofuels. Secondly, what type of biofuel is the ideal fuel molecule that should be targeted. Finally, what microbial system could be used to transform energy resources into the targeted biofuel molecules. In this perspective, the potential of using photosynthetic microbes (cyanobacteria in particular) in the solar energy driven conversion of carbon dioxide to fatty acid-based biofuels is explored. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. Functional nucleic acid-based sensors for heavy metal ion assays.

    Science.gov (United States)

    Zhu, Guichi; Zhang, Chun-yang

    2014-12-21

    Heavy metal contaminants such as lead ions (Pb(2+)), mercury ions (Hg(2+)) and silver ions (Ag(+)) can cause significant harm to humans and generate enduring bioaccumulation in ecological systems. Even though a variety of methods have been developed for Pb(2+), Hg(2+) and Ag(+) assays, most of them are usually laborious and time-consuming with poor sensitivity. Due to their unique advantages of excellent catalytic properties and high affinity for heavy metal ions, functional nucleic acids such as DNAzymes and aptamers show great promise in the development of novel sensors for heavy metal ion assays. In this review, we summarize the development of functional nucleic acid-based sensors for the detection of Pb(2+), Hg(2+) and Ag(+), and especially focus on two categories including the direct assay and the amplification-based assay. We highlight the emerging trends in the development of sensitive and selective sensors for heavy metal ion assays as well.

  7. Boehmite-An Efficient and Recyclable Acid-Base Bifunctional Catalyst for Aldol Condensation Reaction.

    Science.gov (United States)

    Reshma, P C Rajan; Vikneshvaran, Sekar; Velmathi, Sivan

    2018-06-01

    In this work boehmite was used as an acid-base bifunctional catalyst for aldol condensation reactions of aromatic aldehydes and ketones. The catalyst was prepared by simple sol-gel method using Al(NO3)3·9H2O and NH4OH as precursors. The catalyst has been characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), UV-visible spectroscopy (DRS), BET surface area analyses. Boehmite is successfully applied as catalyst for the condensation reaction between 4-nitrobenzaldehyde and acetone as a model substrate giving α, β-unsaturated ketones without any side product. The scope of the reaction is extended for various substituted aldehydes. A probable mechanism has been suggested to explain the cooperative behavior of the acidic and basic sites. The catalyst is environmentally friendly and easily recovered from the reaction mixture. Also the catalyst is reusable up to 3 catalytic cycles.

  8. Studies on (acid + base) equilibria in substituted (phenol + n-butylamine) systems in acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Kozak, A. [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Czaja, M. [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, L. [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail: lech@chem.univ.gda.pl

    2005-08-15

    (Acid + base) equilibria, including molecular heteroconjugation ones, between n-butylamine and one of the following phenols: 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2,5-dinitrophenol, 3-chlorophenol, 4-chlorophenol, 2,3,4,5,6-pentachlorophenol and 2,4,6-tribromophenol have been studied potentiometrically in a protophobic polar aprotic solvent, acetonitrile. Among the phenols studied, 2,5-dinitrophenol exhibited the strongest tendency towards formation of asymmetric hydrogen bonds with n-butylamine, whereas a weakest complex was formed with 2-nitrophenol. In the (n-butylamine + 2,3,4,5,6-pentachlorophenol) and (n-butylamine + 2,4-dinitrophenol) systems proton transfer reactions occurred.

  9. Role of acid-base interactions in synthesis of cordierite from talc and sillimanite group minerals

    Directory of Open Access Journals (Sweden)

    Avvakumov E.G.

    2013-01-01

    Full Text Available It has been found that the mechanical activation of mixtures of sillimanite group minerals with talc and silica additives in grinding-activating devices with periodic and flow action provides significant acceleration of their interaction with formation of cordierite at the subsequent high-temperature treatment. It is shown that the output of cordierite depends on nature of mineral: in mixture with a sillimanite it is considerably higher, than with an andalusite and kyanite, while the rate of mullitization of these minerals has opposite character. It means that the formation of mullite during heat treatment is not a limiting step in synthesis of cordierite. It is shown that the rate of reaction is determined by the difference in the acid-base properties of these minerals, which depend on the coordination of aluminum cations by oxygen ions, different for each of the modifications.

  10. Synthesis and Characterization of Dimmer-Acid-Based Nonisocyanate Polyurethane and Epoxy Resin Composite

    Directory of Open Access Journals (Sweden)

    Xin He

    2017-11-01

    Full Text Available In this study, dimmer-acid-based hybrid nonisocyanate polyurethanes (HNIPUs were synthesized by the one-step method without catalyst. Three polyamines and two epoxy resins were selected as raw materials for HNIPU, and cyclic carbonate was synthesized based on our previous work. All of the products were characterized by Fourier transform infrared spectroscopy (FTIR, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA and dynamic mechanical analysis (DMA. Then, HNIPU coatings were prepared and determined by swelling, water absorption, and water contact angle. The results showed that the HNIPU-4551 have the best mechanical and thermal properties because of its high crosslinking density. Among the different amines, it was confirmed that tetraethylenepentamine was the best amine curing agent for HNIPU coating. Meanwhile, the epoxy resin with a higher epoxy value would also form a higher crosslinking density. Those coatings showed an excellent impact strength, adhesion, flexibility, pencil hardness, hydrophilic, and appropriate crosslinking density.

  11. [The effect of spermine on acid-base equilibrium in DNA molecule].

    Science.gov (United States)

    Slonitskiĭ, S V; Kuptsov, V Iu

    1990-01-01

    The influence of spermine (Sp) on the acid-induced predenaturational and denaturational transitions in the DNA molecule structure has been studied by means of circular dichroism, spectrophotometric and viscometric titration at supporting electrolyte concentration 10 mM NaCl. The data available indicate that at [N]/[P] less than or equal to 0.60 (here [N] and [P] are molar concentrations of Sp nitrogen and DNA phosphours, respectively) the cooperative structural B----B(+)----S transitions are accompanied by the DNA double-helice winding. No competition for proton acceptor sites in the DNA molecule between H+ and Sp4+ cations has been observed when binding to neutral macromolecule. At 0.60 less than or equal to [N]/[P] less than or equal to 0.75 the displacement of the B----B(+)----S transitions midpoints to acidic pH region has been established. This is accompanied by DNA condensation and the appearance of differential scattering of circularly polarized light. The calculations carried out in the framework of the two-variable Manning theory have shown that the acid-induced reduction of the effective polyion charge density facilitates the Sp-induced DNA condensation. It has been shown that the acid-base equilibrium in the DNA molecule is determined by local [H+] in the 2-3 A hydrated monolayer of the macromolecule. An adequate estimation of [H+] can be obtained on the basis of the Poisson-Boltzman approach. The data obtained are consistent with recently proposed hypothesis of polyelectrolyte invariance of the acid-base equilibrium in the DNA molecule.

  12. Equivalence-point electromigration acid-base titration via moving neutralization boundary electrophoresis.

    Science.gov (United States)

    Yang, Qing; Fan, Liu-Yin; Huang, Shan-Sheng; Zhang, Wei; Cao, Cheng-Xi

    2011-04-01

    In this paper, we developed a novel method of acid-base titration, viz. the electromigration acid-base titration (EABT), via a moving neutralization boundary (MNR). With HCl and NaOH as the model strong acid and base, respectively, we conducted the experiments on the EABT via the method of moving neutralization boundary for the first time. The experiments revealed that (i) the concentration of agarose gel, the voltage used and the content of background electrolyte (KCl) had evident influence on the boundary movement; (ii) the movement length was a function of the running time under the constant acid and base concentrations; and (iii) there was a good linearity between the length and natural logarithmic concentration of HCl under the optimized conditions, and the linearity could be used to detect the concentration of acid. The experiments further manifested that (i) the RSD values of intra-day and inter-day runs were less than 1.59 and 3.76%, respectively, indicating similar precision and stability in capillary electrophoresis or HPLC; (ii) the indicators with different pK(a) values had no obvious effect on EABT, distinguishing strong influence on the judgment of equivalence-point titration in the classic one; and (iii) the constant equivalence-point titration always existed in the EABT, rather than the classic volumetric analysis. Additionally, the EABT could be put to good use for the determination of actual acid concentrations. The experimental results achieved herein showed a new general guidance for the development of classic volumetric analysis and element (e.g. nitrogen) content analysis in protein chemistry. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Acid-base titrations using microfluidic paper-based analytical devices.

    Science.gov (United States)

    Karita, Shingo; Kaneta, Takashi

    2014-12-16

    Rapid and simple acid-base titration was accomplished using a novel microfluidic paper-based analytical device (μPAD). The μPAD was fabricated by wax printing and consisted of ten reservoirs for reaction and detection. The reaction reservoirs contained various amounts of a primary standard substance, potassium hydrogen phthalate (KHPth), whereas a constant amount of phenolphthalein was added to all the detection reservoirs. A sample solution containing NaOH was dropped onto the center of the μPAD and was allowed to spread to the reaction reservoirs where the KHPth neutralized it. When the amount of NaOH exceeded that of the KHPth in the reaction reservoirs, unneutralized hydroxide ion penetrated the detection reservoirs, resulting in a color reaction from the phenolphthalein. Therefore, the number of the detection reservoirs with no color change determined the concentration of the NaOH in the sample solution. The titration was completed within 1 min by visually determining the end point, which required neither instrumentation nor software. The volumes of the KHPth and phenolphthalein solutions added to the corresponding reservoirs were optimized to obtain reproducible and accurate results for the concentration of NaOH. The μPADs determined the concentration of NaOH at orders of magnitude ranging from 0.01 to 1 M. An acid sample, HCl, was also determined using Na2CO3 as a primary standard substance instead of KHPth. Furthermore, the μPAD was applicable to the titrations of nitric acid, sulfuric acid, acetic acid, and ammonia solutions. The μPADs were stable for more than 1 month when stored in darkness at room temperature, although this was reduced to only 5 days under daylight conditions. The analysis of acidic hot spring water was also demonstrated in the field using the μPAD, and the results agreed well with those obtained by classic acid-base titration.

  14. Interactive computer-assisted instruction in acid-base physiology for mobile computer platforms.

    Science.gov (United States)

    Longmuir, Kenneth J

    2014-03-01

    In this project, the traditional lecture hall presentation of acid-base physiology in the first-year medical school curriculum was replaced by interactive, computer-assisted instruction designed primarily for the iPad and other mobile computer platforms. Three learning modules were developed, each with ∼20 screens of information, on the subjects of the CO2-bicarbonate buffer system, other body buffer systems, and acid-base disorders. Five clinical case modules were also developed. For the learning modules, the interactive, active learning activities were primarily step-by-step learner control of explanations of complex physiological concepts, usually presented graphically. For the clinical cases, the active learning activities were primarily question-and-answer exercises that related clinical findings to the relevant basic science concepts. The student response was remarkably positive, with the interactive, active learning aspect of the instruction cited as the most important feature. Also, students cited the self-paced instruction, extensive use of interactive graphics, and side-by-side presentation of text and graphics as positive features. Most students reported that it took less time to study the subject matter with this online instruction compared with subject matter presented in the lecture hall. However, the approach to learning was highly examination driven, with most students delaying the study of the subject matter until a few days before the scheduled examination. Wider implementation of active learning computer-assisted instruction will require that instructors present subject matter interactively, that students fully embrace the responsibilities of independent learning, and that institutional administrations measure instructional effort by criteria other than scheduled hours of instruction.

  15. Maternal and fetal Acid-base chemistry: a major determinant of perinatal outcome.

    Science.gov (United States)

    Omo-Aghoja, L

    2014-01-01

    Very small changes in pH may significantly affect the function of various fetal organ systems, such as the central nervous system, and the cardiovascular system with associated fetal distress and poor Apgar score. Review of existing data on maternal-fetal acid-base balance in pregnancy highlight the factors that are associated with derangements of the acid-base status and the impact of the derangements on fetal outcome. Extensive search of electronic databases and manual search of journals for relevant literature on maternal and fetal acid chemistry, clinical studies and case studies were undertaken. There is a substantial reduction in the partial pressure of carbon dioxide (pCO2) in pregnancy. Adequate buffering prevents significant changes in maternal arterial pH. Normal fetal metabolism results in the production of acids which are buffered to maintain extracellular pH within a critical range. Fetal hypoxia can occur when maternal oxygenation is compromised, maternal perfusion of the placenta is reduced, or delivery of oxygenated blood from the placenta to the fetus is impeded. When adequate fetal oxygenation does not occur, metabolisms proceed along with an anaerobic pathway with production of organic acids, such as lactic acid. Accumulation of lactic acid can deplete the buffer system and result in metabolic acidosis with associated low fetal pH, fetal distress and poor Apgar score. There is a significant reduction in pCO2 in pregnancy. This change, however, does not result in a corresponding significant reduction in maternal arterial pH, because of adequate buffering. Very small changes in pH may cause significant derangement in fetal function and outcome.

  16. [ACID-BASE MODULATION OF LYSOZYME ACTIVITY IN MEDIUM FOR CULTIVATION OF ENTEROBACTERIA].

    Science.gov (United States)

    Andryuschenko, S V; Perunova, N B

    2015-01-01

    Determination of modulating effect of acid-base state of medium for cultivation of enterobacteria on activity of C-type lysozyme. Escherichia coli BL21 (DE3) strain for protein expression, Escherichia coli K12 MG1655 model strain, Escherichia coli No. 242 strain, isolated from intestine biotope; 2 Klebsiella pneumoniae strains, one of those contained plasmid homologue of periplasmatic lysozyme inhibitor gene pliC; 1 typical Salmonella enterica ATCC 14028 strain and a Micrococcus luteus ATCC 15307 strain as a control--served as material for the study. The bacteria were cultivated for 24 hours in 2 ml of liquid medium LB at 37 degrees C, 250 rpm. Determination of antilysozyme activity (ALA) was carried out by a photonepehlometrical method according to O.V. Bukharin et al. (1999) with alterations. All the studied microorganisms, including Micrococcus luteus, at the specified conditions 24 hours after cultivation were established to change the pH of the liquid nutrient medium LB from the initial value of 6.6 ± 0.1 to 8.2 ± 0.2 units. ALA determination in the cultivation medium without buffer correction was accompanied by a decline of lysozyme activity at an order of magnitude. The effect was absent during ALA measurement by a standard technique. The local shift of acid-base state of biotope under the conditions of buffer system insufficiency results in a reversible alteration of antimicrobial activity of muramidase, that among other non-specific factors of the environment determines the background of interactions on the level of associative symbiosis. This aspect should be taken into consideration during development of models, that are close to real conditions of microsymbiocenotical interactions.

  17. Investigations of (acid+base) equilibria in systems modelling interactions occurring in biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Kozak, Anna [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Czaja, Malgorzata [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, Lech [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail: lech@chem.univ.gda.pl

    2006-05-15

    By using the potentiometric microtitration method, acidity constants, K{sub a}, anionic, K{sub AHA{sup -}}, and cationic, K{sub BHB{sup +}}, homoconjugation constants, as well as molecular heteroconjugation, K{sub BHA}, constants have been determined in (acid+base) systems formed by the following compounds: acetic acid, phenol, n-butylamine, imidazole, and 4(5)-methylimidazole. These compounds constitute fragments of the side chains of amino acids capable of proton exchange in active sites of enzymes. The (acid+base) equilibria were studied in five polar solvents of different properties, namely in aprotic protophobic acetonitrile, acetone and propylene carbonate, in aprotic protophilic dimethyl sulfoxide and in amphiprotic methanol. The lowest values of the acidity constants of the molecular and cationic acids have been found in aprotic protophobic polar solvents - acetonitrile, propylene carbonate and acetone. Their acid strength have been found to depend on solvent basicity expressed as donor numbers, DN. These media, in particular acetonitrile and acetone, are also favourable for establishing molecular homo- and heteroconjugation equilibria. The most stable homocomplexes are formed in the case of acetic acid (K{sub AHA{sup -}} values range from 2.26 to 3.56 in these media, being more than an order of magnitude higher than those for the remaining compounds). The magnitudes of lgK{sub BHA} reveal that the most stable heterocomplexes are formed by n-butylamine and acetic acid that are characterized by the smallest differences in pK{sub a} values.

  18. [Clinical evaluation of acid-base status: Henderson-Hasselbalch, or Stewart-Fencl approach?

    Science.gov (United States)

    Matoušovic, Karel; Havlín, Jan; Schück, Otto

    Two approaches have been used in clinical evaluation the acid-base status: traditional (bicarbonate-centered) is based on the Henderson-Hasselbalch equation complemented by calculation of the anion gap, and more recent quantitative approach proposed by Stewart and Fencl. The latter method defines the three independent variables, which regulate pH. These include: the difference between the sum of charges carried by strong plasma cations and anions termed the strong ion difference - SID (decrease causes acidosis, and vice versa); the total concentration of the weak non-volatile acids [Atot] (inorganic phosphate and albumin, decrease causes alkalosis and vice versa), and pCO2. According to this approach, pH and bicarbonate are dependent variables. Their concentrations change if and only if one or more independent variables are altered.The main advantage of the Stewart-Fencl approach is the calculation of the concentration of plasma acids, which are not routinely measured. In the traditional approach, their presence is inferred from the anion gap. The correction of the value of anion gap according to the serum albumin level increases the specificity. This correction brings traditional approach closer to the Stewart-Fencl method that precisely calculates unmeasured strong anions by further adjustment of the corrected anion gap according to the serum phosphate, calcium and magnesium levels. The precise calculation of unmeasured anions is important in critically ill patients with the metabolic breakdown, where the traditional approach may overlook the presence of unmeasured anions. Consideration of the sodium-chloride difference draws the attention to acid-base disturbance caused by change of the strong ion difference.

  19. Acid-base equilibrium dynamics in methanol and dimethyl sulfoxide probed by two-dimensional infrared spectroscopy.

    Science.gov (United States)

    Lee, Chiho; Son, Hyewon; Park, Sungnam

    2015-07-21

    Two-dimensional infrared (2DIR) spectroscopy, which has been proven to be an excellent experimental method for studying thermally-driven chemical processes, was successfully used to investigate the acid dissociation equilibrium of HN3 in methanol (CH3OH) and dimethyl sulfoxide (DMSO) for the first time. Our 2DIR experimental results indicate that the acid-base equilibrium occurs on picosecond timescales in CH3OH but that it occurs on much longer timescales in DMSO. Our results imply that the different timescales of the acid-base equilibrium originate from different proton transfer mechanisms between the acidic (HN3) and basic (N3(-)) species in CH3OH and DMSO. In CH3OH, the acid-base equilibrium is assisted by the surrounding CH3OH molecules which can directly donate H(+) to N3(-) and accept H(+) from HN3 and the proton migrates through the hydrogen-bonded chain of CH3OH. On the other hand, the acid-base equilibrium in DMSO occurs through the mutual diffusion of HN3 and N3(-) or direct proton transfer. Our 2DIR experimental results corroborate different proton transfer mechanisms in the acid-base equilibrium in protic (CH3OH) and aprotic (DMSO) solvents.

  20. Controlled synthesis of multi-morphology Te crystals by a convenient Lewis acid/base-assisted solvothermal method

    Science.gov (United States)

    Wu, XiaoPing; Yuan, Lin; Zhou, ShaoMin; Lou, ShiYun; Wang, YongQiang; Gao, Tao; Liu, YuBiao; Shi, XiaoJing

    2012-08-01

    This paper reports on the controlled growth of multi-morphology Te crystals by a convenient Lewis acid/base-assisted solvothermal method for the first time. The morphological transformation from one-dimension (1D) nanostructures to 2D hierarchical flowerlike microarchitecture has been observed. The nanorods and nanowires with a well-defined crystallographical structure and the hierarchical flowers microarchitecture were obtained by changing the Lewis acids/bases. Lewis acids/bases were found to be crucial for the formation of the products by not only acting as the pH regulator but also as the shape controller, owing to their hydrolysis in the solvent to in situ form H+/OH- and hydrates. The results suggest that this should be an effective approach to the control the growth of t-Te crystals with interesting multiple morphologies, which are of interest for both theoretical investigations and practical applications.

  1. Controlled synthesis of multi-morphology Te crystals by a convenient Lewis acid/base-assisted solvothermal method

    International Nuclear Information System (INIS)

    Wu Xiaoping; Yuan Lin; Zhou Shaomin; Lou Shiyun; Wang Yongqiang; Gao Tao; Liu YuBiao; Shi Xiaojing

    2012-01-01

    This paper reports on the controlled growth of multi-morphology Te crystals by a convenient Lewis acid/base-assisted solvothermal method for the first time. The morphological transformation from one-dimension (1D) nanostructures to 2D hierarchical flowerlike microarchitecture has been observed. The nanorods and nanowires with a well-defined crystallographical structure and the hierarchical flowers microarchitecture were obtained by changing the Lewis acids/bases. Lewis acids/bases were found to be crucial for the formation of the products by not only acting as the pH regulator but also as the shape controller, owing to their hydrolysis in the solvent to in situ form H + /OH − and hydrates. The results suggest that this should be an effective approach to the control the growth of t-Te crystals with interesting multiple morphologies, which are of interest for both theoretical investigations and practical applications.

  2. Basic principles of electrolyte chemistry for microfluidic electrokinetics. Part I: Acid-base equilibria and pH buffers.

    Science.gov (United States)

    Persat, Alexandre; Chambers, Robert D; Santiago, Juan G

    2009-09-07

    We review fundamental and applied acid-base equilibrium chemistry useful to microfluidic electrokinetics. We present elements of acid-base equilibrium reactions and derive rules for pH calculation for simple buffers. We also present a general formulation to calculate pH of more complex, arbitrary mixtures of electrolytes, and discuss the effects of ionic strength and temperature on pH calculation. More practically, we offer advice on buffer preparation and on buffer reporting. We also discuss "real world" buffers and likely contamination sources. In particular, we discuss the effects of atmospheric carbon dioxide on buffer systems, namely, the increase in ionic strength and acidification of typical electrokinetic device buffers. In Part II of this two-paper series, we discuss the coupling of acid-base equilibria with electrolyte dynamics and electrochemistry in typical microfluidic electrokinetic systems.

  3. [Facial injections of hyaluronic acid-based fillers for malformations. Preliminary study regarding scar tissue improvement and cosmetic betterment].

    Science.gov (United States)

    Franchi, G; Neiva-Vaz, C; Picard, A; Vazquez, M-P

    2018-02-02

    Cross-linked hyaluronic acid-based fillers have gained rapid acceptance for treating facial wrinkles, deep tissue folds and sunken areas due to aging. This study evaluates, in addition to space-filling properties, their effects on softness and elasticity as a secondary effect, following injection of 3 commercially available cross-linked hyaluronic acid-based fillers (15mg/mL, 17,5mg/mL and 20mg/mL) in patients presenting with congenital or acquired facial malformations. We started injecting gels of cross-linked hyaluronic acid-based fillers in those cases in 2013; we performed 46 sessions of injections in 32 patients, aged from 13-32. Clinical assessment was performed by the patient himself and by a plastic surgeon, 15 days after injections and 6-18 months later. Cross-linked hyaluronic acid-based fillers offered very subtle cosmetic results and supplemented surgery with a very high level of satisfaction of the patients. When injected in fibrosis, the first session enhanced softness and elasticity; the second session enhanced the volume. Cross-linked hyaluronic acid-based fillers fill sunken areas and better softness and elasticity of scar tissues. In addition to their well-understood space-filling function, as a secondary effect, the authors demonstrate that cross-linked hyaluronic acid-based fillers improve softness and elasticity of scarring tissues. Many experimental studies support our observations, showing that cross-linked hyaluronic acid stimulates the production of several extra-cellular matrix components, including dermal collagen and elastin. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  4. Influence of kinetics on the determination of the surface reactivity of oxide suspensions by acid-base titration.

    Science.gov (United States)

    Duc, M; Adekola, F; Lefèvre, G; Fédoroff, M

    2006-11-01

    The effect of acid-base titration protocol and speed on pH measurement and surface charge calculation was studied on suspensions of gamma-alumina, hematite, goethite, and silica, whose size and porosity have been well characterized. The titration protocol has an important effect on surface charge calculation as well as on acid-base constants obtained by fitting of the titration curves. Variations of pH versus time after addition of acid or base to the suspension were interpreted as diffusion processes. Resulting apparent diffusion coefficients depend on the nature of the oxide and on its porosity.

  5. Comparative bioavailability studies of citric acid and malonic acid based aspirin effervescent tablets

    Directory of Open Access Journals (Sweden)

    Anju Gauniya

    2010-01-01

    Full Text Available Purpose: The present investigation is aimed at comparing the pharmacokinetic profile (Bioavailability of aspirin in tablet formulations, which were prepared by using different effervescent excipients such as citric acid and malonic acid. Materials and Methods: The relative bioavailability and pharmacokinetics of citric acid based aspirin effervescent tablet (Product A and malonic acid based aspirin effervescent tablet (Product B formulations were evaluated for an in-vitro dissolution study and in-vivo bioavailability study, in 10 normal healthy rabbits. The study utilized a randomized, crossover design with a one-week washout period between doses. Blood samples were collected at 0, 1, 2, 4, 6, 8, 12 and 24 hours following a 100 mg/kg dose. Plasma samples were assayed by High Performance Liquid Chromatography. T max , C max , AUC 0-24 , AUC 0- ∞, MRT, K a, and relative bioavailability were estimated using the traditional pharmacokinetic methods and were compared by using the paired t-test. Result: In the present study, Products A and B showed their T max , C max , AUC 0-24 , AUC 0- ∞, MRT, and K a values as 2.5 h, 2589 ± 54.79 ng/ml, 9623 ± 112.87 ng.h/ml, 9586 ± 126.22 ng.h/ml, 3.6 ± 0.10 h, and 0.3698 ± 0.003 h -1 for Product A and 3.0 h, 2054 ± 55.79 ng/ml, 9637 ± 132.87 ng.h/ml, 9870 ± 129.22 ng.h/ml, 4.76 ± 0.10 h, and 0.3812 ± 0.002 h -1 for Product B, respectively. Conclusion: The results of the paired t-test of pharmacokinetics data showed that there was no significant difference between Products A and B. From both the in vitro dissolution studies and in vivo bioavailability studies it was concluded that products A and B had similar bioavailability.

  6. Theoretical Determination of One-Electron Oxidation Potentials for Nucleic Acid Bases.

    Science.gov (United States)

    Psciuk, Brian T; Lord, Richard L; Munk, Barbara H; Schlegel, H Bernhard

    2012-12-11

    The oxidation potentials for N-methyl substituted nucleic acid bases guanine, adenine, cytosine, thymine, uracil, xanthine, and 8-oxoguanine were computed using B3LYP and CBS-QB3 with the SMD solvation model. Acid-base and tautomeric equilibria present in aqueous solution were accounted for by combining standard redox potentials with calculated pKa and tautomerization energies to produce an ensemble averaged pH dependent potential. Gas phase free energies were computed using B3LYP/aug-cc-pVTZ//B3LYP/6-31+G(d,p) and CBS-QB3. Solvation free energies were computed at the SMD/B3LYP/6-31+G(d,p) level of theory. Compared to experimental results, calculations with the CBS-QB3 level of theory have a mean absolute error (MAE) of ca. 1 kcal/mol for the gas phase proton affinity/gas phase basicity and an MAE of ca. 0.04 eV for the adiabatic/vertical ionization potentials. The B3LYP calculations have a MAE of ∼2 kcal/mol for the proton affinity/gas phase basicity data but systematically underestimated ionization potentials by 0.14-0.21 eV. Solvent cavities for charged solute species were rescaled uniformly by fitting computed pKa data to experimentally measured pKa values. After solvent cavity scaling, the MAEs for computed pKa's compared to experimental results are 0.7 for B3LYP and 0.9 for CBS-QB3. In acetonitrile, the computed E°(XH(+•)/XH) redox potentials are systematically lower than experimentally measured potentials by 0.21 V for CBS-QB3 and 0.33 V for B3LYP. However, the redox potentials relative to adenine are in very good agreement with experimental results, with MAEs of 0.10 V for CBS-QB3 and 0.07 V for B3LYP. In aqueous solution, B3LYP and CBS-QB3 have MAEs of 0.21 and 0.19 V for E7(X(•),H(+)/XH). Replacing the methyl substituent with ribose changes the calculated E7 potentials by 0.1-0.2 V. The calculated difference between the guanine and adenine oxidation potentials is too large compared to experimental results, but the calculated difference between

  7. Correlating multidimensional fetal heart rate variability analysis with acid-base balance at birth

    International Nuclear Information System (INIS)

    Frasch, Martin G; Durosier, Lucien D; Xu, Yawen; Wang, Xiaogang; Gao, Xin; Stampalija, Tamara; Herry, Christophe; Seely, Andrew JE; Casati, Daniela; Ferrazzi, Enrico; Alfirevic, Zarko

    2014-01-01

    Fetal monitoring during labour currently fails to accurately detect acidemia. We developed a method to assess the multidimensional properties of fetal heart rate variability (fHRV) from trans-abdominal fetal electrocardiogram (fECG) during labour. We aimed to assess this novel bioinformatics approach for correlation between fHRV and neonatal pH or base excess (BE) at birth. We enrolled a prospective pilot cohort of uncomplicated singleton pregnancies at 38–42 weeks’ gestation in Milan, Italy, and Liverpool, UK. Fetal monitoring was performed by standard cardiotocography. Simultaneously, with fECG (high sampling frequency) was recorded. To ensure clinician blinding, fECG information was not displayed. Data from the last 60 min preceding onset of second-stage labour were analyzed using clinically validated continuous individualized multiorgan variability analysis (CIMVA) software in 5 min overlapping windows. CIMVA allows simultaneous calculation of 101 fHRV measures across five fHRV signal analysis domains. We validated our mathematical prediction model internally with 80:20 cross-validation split, comparing results to cord pH and BE at birth. The cohort consisted of 60 women with neonatal pH values at birth ranging from 7.44 to 6.99 and BE from −0.3 to −18.7 mmol L −1 . Our model predicted pH from 30 fHRV measures (R 2 = 0.90, P < 0.001) and BE from 21 fHRV measures (R 2 = 0.77, P < 0.001). Novel bioinformatics approach (CIMVA) applied to fHRV derived from trans-abdominal fECG during labor correlated well with acid-base balance at birth. Further refinement and validation in larger cohorts are needed. These new measurements of fHRV might offer a new opportunity to predict fetal acid-base balance at birth. (fast track communication)

  8. Variability of Acid-Base Status in Acetate-Free Biofiltration 84% versus Bicarbonate Dialysis

    Directory of Open Access Journals (Sweden)

    Harzallah Kais

    2008-01-01

    Full Text Available The ultimate goal of hemodialysis (HD treatment is to achieve the highest level of efficacy in the presence of maximal clinical tolerance. With an aim to offer good hemodynamic stability, as observed during the acetate-free biofiltration 14% (AFB 14% to patients who are intolerant to bicarbonate dialysis (BD and with less cost, we have developed since June 1994, a new HD technique, namely AFB 84%. This study was carried out to analyze acid-base variations during the AFB 84% in comparison to BD in hemodynamically stable patients on regular HD. This was a prospective randomized crossover study carried out on 12 patients (6 males and 6 females for a total of 144 HD sessions (72 BD and 72 AFB 84%. Patients with decompensated cardiomyopathy, respiratory diseases or uncontrolled hypertension were not included in the trial. All the patients were treated with BD or AFB 84%; the latter is characterized by the absence of acetate in the dialysate and a complete correction of buffer balance by post-dilutional infusion of bicarbonate-based replacement solution. The comparison of pre-dialysis arterial acid-base and blood-gas parameters revealed no significant differences of pH, HCO 3 - and paCO 2 levels between the two techniques. Analysis of post-dialysis parameters showed that, among patients dialyzed with BD, there was over correction of metabolic acidosis with a tendency towards metabolic alkalosis. In contrast, in patients dialyzed with AFB 84%, we observed a significant improvement in pH and HCO 3 - levels but the increase in paCO2 level was not significant. A comparison of these parameters between the two techniques showed statistically significant difference in pH, HCO3 - and paCO2 levels, but not for paO2 level. AFB 84% can offer some important advantages with the complete absence of acetate from the substitution fluids, and permits a better correction of metabolic acidosis than BD, without causing alkalosis.

  9. Acid-base behavior in hydrothermal processing of wastes. 1998 annual progress report

    International Nuclear Information System (INIS)

    Johnson, K.P.; Rossky, P.J.

    1998-01-01

    'A new technology, hydrothermal oxidation (also called supercritical water oxidation), is being developed to treat high level nuclear wastes. Nitrates are reduced to nitrogen; furthermore, phosphates, alumina sludge, and chromium are solubilized, and the sludge is reconstituted as fine oxide particles. A major obstacle to development of this technology has been a lack of scientific knowledge of chemistry in hydrothermal solution above 350 C, particularly acid-base behavior, and transport phenomena, which is needed to understand corrosion, metal-ion complexation, and salt precipitation and recovery. The objective is to provide this knowledge with in-situ UV-vis spectroscopic measurements and fully molecular computer simulation. A major objective of the experimental studies has been to determine the equilibria for Cr(VI) up to 420 C as this is a key species to be removed from nuclear wastes. A wide range of concentrations of KOH and perchloric acid were utilized to manipulate the acid-base equilibria and to understand the effects of ion solvation and ion pairing. The second system is the equilibria between nitric acid, nitrous acid, nitrogen dioxide, nitrite and nitrate ions and oxygen. For both of these systems, chemical equilibria has not been measured previously in hydrothermal solution at these temperatures. On the theoretical side, the authors have focused on the study of the transport properties of aqueous ions in supercritical water. The motivation for these studies is two fold. First, although transport coefficients are fundamental to solution chemistry reaction rates, the behavior of such transport properties over wide ranges of density and temperature are not well established experimentally, particularly at the densities typically of interest (< 0.5 g/cc). Second, due to practical challenges, ionic association equilibria in SCW is typically accessed via measurements of conductivity followed by analysis through a theoretical model that incorporates ion

  10. Roles of Renal Proximal Tubule Transport in Acid/Base Balance and Blood Pressure Regulation

    Directory of Open Access Journals (Sweden)

    Motonobu Nakamura

    2014-01-01

    Full Text Available Sodium-coupled bicarbonate absorption from renal proximal tubules (PTs plays a pivotal role in the maintenance of systemic acid/base balance. Indeed, mutations in the Na+-HCO3- cotransporter NBCe1, which mediates a majority of bicarbonate exit from PTs, cause severe proximal renal tubular acidosis associated with ocular and other extrarenal abnormalities. Sodium transport in PTs also plays an important role in the regulation of blood pressure. For example, PT transport stimulation by insulin may be involved in the pathogenesis of hypertension associated with insulin resistance. Type 1 angiotensin (Ang II receptors in PT are critical for blood pressure homeostasis. Paradoxically, the effects of Ang II on PT transport are known to be biphasic. Unlike in other species, however, Ang II is recently shown to dose-dependently stimulate human PT transport via nitric oxide/cGMP/ERK pathway, which may represent a novel therapeutic target in human hypertension. In this paper, we will review the physiological and pathophysiological roles of PT transport.

  11. FERTILIZATION OF VINE BY A 5-AMINOLEVULINIC ACID-BASED FERTILIZER AND ITS PROFITABILITY

    Directory of Open Access Journals (Sweden)

    VLADIMR IMANSK

    2013-03-01

    Full Text Available In this work we investigated the effect of different doses of NPKS fertilizer added into the soil for nutrient contents in the soil, as well as the quantity and quality of grapes. During the vegetation of the vine, we tested the 5-aminolevulinic acid-based fertilizer (ALA. We summarize that higher doses of fertilizer added into soil caused higher amounts of available nutrients. During the vegetation of the vine an increase of ALA had a positive effect on the optimal balance of nutrients. Fertilization also increased the grape-vine yield, with the strongest effect (by 68% observed due to the application of ALA during the vegetation period of the vine. Added fertilizers had a statistically significant influence on decreased sugar concentration in the grape-vine however the addition of fertilizer into the soil, mainly the application of ALA during vegetation of the vine (by 57% had a positive effect on increase of the total content of sugar in the grape-vine, produced on 1 hectare. The year had a significant influence on the economical evaluation.

  12. Proton exchange in acid-base complexes induced by reaction coordinates with heavy atom motions

    Energy Technology Data Exchange (ETDEWEB)

    Alavi, Saman, E-mail: saman.alavi@nrc-cnrc.gc.ca [Steacie Institute for Molecular Sciences, National Research Council of Canada, Ontario, K1A 0R6 (Canada); Taghikhani, Mahdi [Department of Chemistry, Sharif Institute of Technology, Tehran (Iran, Islamic Republic of)

    2012-06-19

    Highlights: Black-Right-Pointing-Pointer Proton exchange in acid-base complexes is studied. Black-Right-Pointing-Pointer The structures, binding energies, and normal mode vibrations are calculated. Black-Right-Pointing-Pointer Transition state structures of proton exchange mechanism are determined. Black-Right-Pointing-Pointer In the complexes studied, the reaction coordinate involves heavy atom rocking. Black-Right-Pointing-Pointer The reaction coordinate is not simply localized in the proton movements. - Abstract: We extend previous work on nitric acid-ammonia and nitric acid-alkylamine complexes to illustrate that proton exchange reaction coordinates involve the rocking motion of the base moiety in many double hydrogen-bonded gas phase strong acid-strong base complexes. The complexes studied involve the biologically and atmospherically relevant glycine, formic, acetic, propionic, and sulfuric acids with ammonia/alkylamine bases. In these complexes, the magnitude of the imaginary frequencies associated with the proton exchange transition states are <400 cm{sup -1}. This contrasts with widely studied proton exchange reactions between symmetric carboxylic acid dimers or asymmetric DNA base pair and their analogs where the reaction coordinate is localized in proton motions and the magnitude of the imaginary frequencies for the transition states are >1100 cm{sup -1}. Calculations on complexes of these acids with water are performed for comparison. Variations of normal vibration modes along the reaction coordinate in the complexes are described.

  13. Stearic acid based oleogels: a study on the molecular, thermal and mechanical properties.

    Science.gov (United States)

    Sagiri, S S; Singh, Vinay K; Pal, K; Banerjee, I; Basak, Piyali

    2015-03-01

    Stearic acid and its derivatives have been used as gelators in food and pharmaceutical gel formulations. However, the mechanism pertaining to the stearic acid based gelation has not been deciphered yet. Keeping that in mind, we investigated the role of stearic acid on physic-chemical properties of oleogel. For this purpose, two different oil (sesame oil and soy bean oil) formulations/oleogels were prepared. In depth analysis of gel kinetics, gel microstructure, molecular interactions, thermal and mechanical behaviors of the oleogels were done. The properties of the oleogels were dependent on the type of the vegetable oil used and the concentration of the stearic acid. Avrami analysis of DSC thermograms indicated that heterogeneous nucleation was coupled with the one-dimensional growth of gelator fibers as the key phenomenon in the formation of oleogels. Viscoelastic and pseudoplastic nature of the oleogels was analyzed in-depth by fitting the stress relaxation data in modified Peleg's model and rheological studies, respectively. Textural studies have revealed that the coexistence of hydrogen bond dissipation and formation of new bonds is possible under stress conditions in the physical oleogels. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Thermo-oxidation, friction-reducing and physicochemical properties of ricinoleic acid based-diester biolubricants

    Directory of Open Access Journals (Sweden)

    Nadia Salih

    2017-05-01

    Full Text Available A major global effort is currently underway to reduce dependence on petroleum products and minimize the impact of their derivatives on the environment. Plant oils are being investigated as a potential source of environmentally favorable lubricants given their combination of biodegradability, renewability and excellent lubrication performance. Low oxidation and thermal stability, poor low-temperature properties and a narrow range of available viscosities, however, limit their potential application as industrial biolubricants. The chemical modification of plant fatty acid structures has great potential for improving the physicochemical and friction-reducing properties of these compounds. This paper presents the thermo-oxidation, friction-reducing and physicochemical properties of a series of diester compounds derived from ricinoleic acid as biolubricant basestocks. The results indicated that among the synthesized ricinoleic acid-based diester compounds, octyl 10,12-dihydroxy-9-behenoxystearate 16 has the lowest pour point (−53.26 °C, while octyl 10,12-dihydroxy-9-octyloxystearate 10 has the highest onset temperature (128.98 °C and the lowest volatile loss and quantity of insoluble deposits (68.78% and 77.25%, respectively. The friction-reducing results indicate an improvement occurred in the presence of longer mid-chain esters and an increased polarity in the ester functional group. The data indicate that some synthesized derivatives have significant potential as environmentally friendly biolubricant basestocks.

  15. Sustained wound healing activity of curcumin loaded oleic acid based polymeric bandage in a rat model.

    Science.gov (United States)

    Mohanty, Chandana; Das, Manasi; Sahoo, Sanjeeb K

    2012-10-01

    Wound healing is an intricate multistage process that includes inflammation, cell proliferation, matrix deposition and remodeling phases. It is often associated with oxidative stress and consequent prolonged inflammation, resulting in impaired wound healing. Curcumin has been reported to improve wound healing in different animal models. In order to increase the efficacy of curcumin in the healing arena a curcumin loaded oleic acid based polymeric (COP) bandage was formulated. The in vivo wound healing potency was compared with void bandage and control (cotton gauze treatment) in a rat model. Biochemical parameters and histological analysis revealed increased wound reduction and enhanced cell proliferation in COP bandage treated groups due to its efficient free radical scavenging properties. Comparative acceleration in wound healing was due to early implementation of fibroblasts and its differentiation (increased level of α-smooth muscle actin). Western blotting and semiquantitative PCR analysis clearly indicate that COP bandage can efficiently quench free radicals leading to reduced antioxidative enzyme activity. Further evidence at mRNA and protein level indicates that our system is potent enough to reduce the inflammatory response mediated by the NFκB pathway during wound healing. With this background, we anticipate that such a versatile approach may seed new arena for topical wound healing in the near future.

  16. Temperature dependence of the acid base equilibrium constants of substituted pyridine N-oxides in acetonitrile

    Science.gov (United States)

    Kaczmarczyk, Ewa; Wróbel, Roman; Liwo, Adam; Chmurzyński, Lech

    1999-03-01

    Temperature dependence of acid-base equilibrium constants in systems consisting of substituted pyridine N-oxides was studied in acetonitrile, a strongly ionizing polar protophobic aprotic solvent. N-oxides, which have an enhanced tendency towards formation of cationic homo- and heteroconjugates, (OHO +) as a result of their relatively strong basicity, were investigated. For the sake of comparison, also aliphatic trimethylamine N-oxide and pyridine, the parent compound of its N-oxide, were included. Of particular interest were acid dissociation constants of cations of the protonated bases, homoconjugation equilibria of the cationic acids with conjugate bases, as well as cationic heteroconjugation equilibria of the protonated bases with non-conjugated bases. The constants were determined at three temperatures, 292.1, 298.1 and 304.1 K. On the basis of the temperature dependence of the constants, enthalpy changes were calculated for the acid dissociation of the cationic acids, as well as for cationic homo- and heteroconjugation. These values were derived from the known thermodynamic relationships, Δ G = - RTln K and Δ G = Δ H - TΔ S. It has been found that enthalpy changes for the dissociation reactions of the cationic acids and for cationic homoconjugation reactions are consistent with the variations of the protonation and homoconjugation energies, respectively calculated by both the semi-empirical and the ab initio methods on the 4-31G level.

  17. American Society of Nephrology Quiz and Questionnaire 2013: electrolyte and acid-base.

    Science.gov (United States)

    Palmer, Biff F; Perazella, Mark A; Choi, Michael J

    2014-06-06

    The Nephrology Quiz and Questionnaire (NQ&Q) remains an extremely popular session for attendees of the annual meeting of the American Society of Nephrology. As in past years, the conference hall was overflowing with interested audience members. Topics covered by expert discussants included electrolyte and acid-base disorders, glomerular disease, ESRD/dialysis, and transplantation. Complex cases representing each of these categories along with single-best-answer questions were prepared by a panel of experts. Prior to the meeting, program directors of United States nephrology training programs answered questions through an Internet-based questionnaire. A new addition to the NQ&Q was participation in the questionnaire by nephrology fellows. To review the process, members of the audience test their knowledge and judgment on a series of case-oriented questions prepared and discussed by experts. Their answers are compared in real time using audience response devices with the answers of nephrology fellows and training program directors. The correct and incorrect answers are then briefly discussed after the audience responses, and the results of the questionnaire are displayed. This article recapitulates the session and reproduces its educational value for the readers of CJASN. Enjoy the clinical cases and expert discussions. Copyright © 2014 by the American Society of Nephrology.

  18. Bicarbonate Concentration, Acid-Base Status, and Mortality in the Health, Aging, and Body Composition Study

    Science.gov (United States)

    Murphy, Rachel A.; Shlipak, Michael G.; Satterfield, Suzanne; Huston, Hunter K.; Sebastian, Anthony; Sellmeyer, Deborah E.; Patel, Kushang V.; Newman, Anne B.; Sarnak, Mark J.; Ix, Joachim H.; Fried, Linda F.

    2016-01-01

    Background and objectives Low serum bicarbonate associates with mortality in CKD. This study investigated the associations of bicarbonate and acid-base status with mortality in healthy older individuals. Design, setting, participants, & measurements We analyzed data from the Health, Aging, and Body Composition Study, a prospective study of well functioning black and white adults ages 70–79 years old from 1997. Participants with arterialized venous blood gas measurements (n=2287) were grouped into metabolic acidosis, 1.21 (95% CI, 1.01 to 1.46) for respiratory alkalosis, and 1.35 (95% CI, 1.08 to 1.69) for metabolic alkalosis categories. Respiratory acidosis did not associate with mortality. Conclusions In generally healthy older individuals, low serum bicarbonate associated with higher mortality independent of systemic pH and potential confounders. This association seemed to be present regardless of whether the cause of low bicarbonate was metabolic acidosis or respiratory alkalosis. Metabolic alkalosis also associated with higher mortality. PMID:26769766

  19. Biodiesel Production from Spent Fish Frying Oil Through Acid-Base Catalyzed Transesterification

    Directory of Open Access Journals (Sweden)

    Abdalrahman B. Fadhil

    2012-06-01

    Full Text Available Biodiesel fuels were prepared from a special type of frying oil namely spent fish frying oil through two step transesterification viz. acid-base catalyzed transesterification. Hydrochloric acid and potassium hydroxide with methanol were used for this purpose. The oil was pre-treated with (1.0 wt% HCl and methanol to reduce free fatty acids content of the oil. Then, conditions of the base catalyzed step such as base concentration, reaction temperature, methanol to oil molar ratio and reaction time were optimized. The study raveled that, 0.50% KOH w/w of oil; a 6:1 methanol to oil molar ratio; a reaction temperature of 60°C and a duration of 1h were the optimal conditions because they resulted in high biodiesel yield. Fuel properties of the products were assessed and found better than those of the parent oil. Furthermore, they met the specified limits according to the ASTM standards. Thin layer chromatography was used as a simple technique to monitor the transesterification of the oil. Blending of the optimal biodiesel sample with petro diesel using specified volume percentages was done as well. The results indicated that biodiesel had slight effect on the values of the assessed properties.

  20. Acid-base titration of melanocortin peptides: evidence of Trp rotational conformers interconversion.

    Science.gov (United States)

    Fernandez, Roberto M; Vieira, Renata F F; Nakaie, Clóvis R; Lamy, M Teresa; Ito, Amando S

    2005-01-01

    Tryptophantime-resolved fluorescence was used to monitor acid-base titration properties of alpha-melanocyte stimulating hormone (alpha-MSH) and the biologically more potent analog [Nle4, D-Phe7]alpha -MSH (NDP-MSH), labeled or not with the paramagnetic amino acid probe 2,2,6,6-tetramthylpiperidine-N-oxyl-4-amino-4-carboxylic acid (Toac). Global analysis of fluorescence decay profiles measured in the pH range between 2.0 and 11.0 showed that, for each peptide, the data could be well fitted to three lifetimes whose values remained constant. The less populated short lifetime component changed little with pH and was ascribed to Trp g+ chi1 rotamer, in which electron transfer deactivation predominates over fluorescence. The long and intermediate lifetime preexponential factors interconverted along that pH interval and the result was interpreted as due to interconversion between Trp g- and trans chi1 rotamers, driven by conformational changes promoted by modifications in the ionization state of side-chain residues. The differences in the extent of interconversion in alpha-MSH and NDP-MSH are indicative of structural differences between the peptides, while titration curves suggest structural similarities between each peptide and its Toac-labeled species, in aqueous solution. Though less sensitive than fluorescence, the Toac electron spin resonance (ESR) isotropic hyperfine splitting parameter can also monitor the titration of side-chain residues located relatively far from the probe. Copyright (c) 2005 Wiley Periodicals, Inc.

  1. Sequential injection redox or acid-base titration for determination of ascorbic acid or acetic acid.

    Science.gov (United States)

    Lenghor, Narong; Jakmunee, Jaroon; Vilen, Michael; Sara, Rolf; Christian, Gary D; Grudpan, Kate

    2002-12-06

    Two sequential injection titration systems with spectrophotometric detection have been developed. The first system for determination of ascorbic acid was based on redox reaction between ascorbic acid and permanganate in an acidic medium and lead to a decrease in color intensity of permanganate, monitored at 525 nm. A linear dependence of peak area obtained with ascorbic acid concentration up to 1200 mg l(-1) was achieved. The relative standard deviation for 11 replicate determinations of 400 mg l(-1) ascorbic acid was 2.9%. The second system, for acetic acid determination, was based on acid-base titration of acetic acid with sodium hydroxide using phenolphthalein as an indicator. The decrease in color intensity of the indicator was proportional to the acid content. A linear calibration graph in the range of 2-8% w v(-1) of acetic acid with a relative standard deviation of 4.8% (5.0% w v(-1) acetic acid, n=11) was obtained. Sample throughputs of 60 h(-1) were achieved for both systems. The systems were successfully applied for the assays of ascorbic acid in vitamin C tablets and acetic acid content in vinegars, respectively.

  2. Syntheses of Azo-Imine Derivatives from Vanillin as an Acid Base Indicator

    Directory of Open Access Journals (Sweden)

    Bambang Purwono

    2013-05-01

    Full Text Available Preparations of azo, imine and azo-imine derivatives from vanillin as an indicator of acid-base titration have been carried out. The azo derivative of 4-hydroxy-3-methoxy-5-(phenylazobenzaldehyde 2 was produced by diazotitation reaction of vanillin in 37.04% yield. The azo product was then refluxed with aniline in ethanol to yield azo-imine derivatives, 2-methoxy-6-(phenylazo-4-((phenyliminomethylphenol 1 in 82.21% yield. The imine derivative, 2-methoxy-4-((phenyliminomethyl-phenol 3 was obtained by refluxing of vanillin and aniline mixture in ethanol solvent and produced 82.17% yield. The imine product was then reacted with benzenediazonium chloride salt. However, the products indicated hydrolyzed product of 4-hydroxy-3-methoxy-5-(phenylazobenzaldehyde 2 in 22.15% yield. The 2-methoxy-4-((phenyliminomethylphenol 2 could be used as an indicator for titration of NaOH by H2C2O4 with maximum concentration of H2C2O4 0.1 M while the target compound 1 could be used as titration indicator for titration of NaOH with H2C2O4 with same result using phenolphthalein indicator.

  3. The first proton sponge-based amino acids: synthesis, acid-base properties and some reactivity.

    Science.gov (United States)

    Ozeryanskii, Valery A; Gorbacheva, Anastasia Yu; Pozharskii, Alexander F; Vlasenko, Marina P; Tereznikov, Alexander Yu; Chernov'yants, Margarita S

    2015-08-21

    The first hybrid base constructed from 1,8-bis(dimethylamino)naphthalene (proton sponge or DMAN) and glycine, N-methyl-N-(8-dimethylamino-1-naphthyl)aminoacetic acid, was synthesised in high yield and its hydrobromide was structurally characterised and used to determine the acid-base properties via potentiometric titration. It was found that the basic strength of the DMAN-glycine base (pKa = 11.57, H2O) is on the level of amidine amino acids like arginine and creatine and its structure, zwitterionic vs. neutral, based on the spectroscopic (IR, NMR, mass) and theoretical (DFT) approaches has a strong preference to the zwitterionic form. Unlike glycine, the DMAN-glycine zwitterion is N-chiral and is hydrolytically cleaved with the loss of glycolic acid on heating in DMSO. This reaction together with the mild decarboxylative conversion of proton sponge-based amino acids into 2,3-dihydroperimidinium salts under air-oxygen was monitored with the help of the DMAN-alanine amino acid. The newly devised amino acids are unique as they combine fluorescence, strongly basic and redox-active properties.

  4. Do over 200 million healthy altitude residents really suffer from chronic Acid-base disorders?

    Science.gov (United States)

    Zubieta-Calleja, Gustavo; Zubieta-Castillo, Gustavo; Zubieta-Calleja, Luis; Ardaya-Zubieta, Gustavo; Paulev, Poul-Erik

    2011-01-01

    As the oxygen tension of inspired air falls with increasing altitude in normal subjects, hyperventilation ensues. This acute respiratory alkalosis, induces increased renal excretion of bicarbonate, returning the pH back to normal, giving rise to compensated respiratory alkalosis or chronic hypocapnia. It seems a contradiction that so many normal people at high altitude should permanently live as chronic acid-base patients. Blood gas analyses of 1,865 subjects at 3,510 m, reported a P(a)CO(2) (arterial carbon dioxide tension ± SEM) = 29.4 ± 0.16 mmHg and pH = 7.40 ± 0.005. Base excess, calculated with the Van Slyke sea level equation, is -5 mM (milliMolar or mmol/l) as an average, suggesting chronic hypocapnia. THID, a new term replacing "Base Excess" is determined by titration to a pH of 7.40 at a P(a)CO(2) of 5.33 kPa (40 mmHg) at sea level, oxygen saturated and at 37°C blood temperature. Since our new modified Van Slyke equations operate with normal values for P(a)CO(2) at the actual altitude, a calculation of THID will always result in normal values-that is, zero.

  5. Determination of surface charge density of α-alumina by acid-base titration

    Directory of Open Access Journals (Sweden)

    Justin W. Ntalikwa

    2007-04-01

    Full Text Available The surface charge density (σo of colloidal alpha alumina suspended in various 1:1 electrolytes was measured using acid-base titration. An autotitrator capable of dispensing accurately 25 plus or minus 0.1 μL of titrant was used. The pH and temperature in the titration cell were monitored using single junction electrodes and platinum resistance thermometers, respectively. A constant supply of nitrogen gas in the cell was used to maintain inert conditions. The whole set up was interfaced with a computer for easy data acquisition. It was observed that the material exhibits a point of zero charge (PZC, this occurred at pH of 7.8 plus or minus 0.1, 7.6 plus or minus 0.2, 8.5 plus or minus 0.1, 8.3 plus or minus 0.1 for NaCl, NaNO3, CsCl and CsNO3 systems, respectively. It was also observed that below PZC, σo increases with increase in electrolyte concentration (Co whereas above PZC, σo decreases with increase in Co. It was concluded that σo of this material is a function of pH and Co and that its polarity can be varied through zero by varying these parameters.

  6. Abridged acid-base wet-milling synthesis of high purity hydroyapatite

    Directory of Open Access Journals (Sweden)

    Sandi Carolina Ruiz-Mendoza

    2008-06-01

    Full Text Available There is a plethora of routes to produce hydroxyapatite(HA and in general calcium phosphates(CP but production usually leads to a mixture of several phases. Besides ionic contamination, most of these methods are cumbersome, restricted to small volumes of product and require a lot of thermal energy. The acid-base route eliminates foreign ions or additives and its only byproduct is water. Heterogeneous reaction drawback is that solid reactants do not easily come in contact with each other and therefore addition and stirring times become very lengthy and still the product is a mixture. The synthesis started from calcium hydroxide and phosphoric acid (PA. Ball milling was used to favor kinetics and stoichiometry. Six sets of PA addition, paddle stirring and ball milling times were used. Products were evaluated by X ray diffraction (XRD, Fourier Transform Infrared (FTIR, scanning electron microscopy (SEM, X ray fluorescence (XRF and Ca/P ratio. Chemical analysis for calcium proceeded through oxalate precipitate and phosphorus by the phosphomolibdate technique. A set of conditions yielding high purity HA was established.

  7. Orderly Layered Zr-Benzylphosphonate Nanohybrids for Efficient Acid-Base-Mediated Bifunctional/Cascade Catalysis.

    Science.gov (United States)

    Li, Hu; Fang, Zhen; He, Jian; Yang, Song

    2017-02-22

    The development of functional metal-organic materials that are robust and active for bifunctional/cascade catalysis is of great significance. Herein, a series of mesoporous and orderly layered nanohybrids were synthesized for the first time through simple and template-free assembly of ortho-, meta-, or para-xylylenediphosphonates (o-, p-, or m-PhP) containing zirconium. It was found that m-PhPZr nanoparticles (20-50 nm) with mesopores centered at 7.9 nm and high Lewis acid-base site ratio (1:0.7) showed excellent performance under mild conditions (as low as 82 °C) in transfer hydrogenation of carbonyl compounds, including bioaldehydes and alcohols, with near quantitative yields and little Zr leaching. Isotopic labeling studies indicated the occurrence of direct hydrogen transfer rather than metal hydride route by bifunctional catalysis. Lewis acidic (Zr) and basic (PO 3 ) centers of the heterogeneous catalyst were further revealed to play a synergistic role in one-pot cascade transformations, for example, of ethyl levulinate to γ-valerolactone and glucose to 5-hydroxymethylfurfural. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Real-time nucleic acid-based detection methods for pathogenic bacteria in food.

    Science.gov (United States)

    McKillip, John L; Drake, Maryanne

    2004-04-01

    Quality assurance in the food industry in recent years has involved the acceptance and implementation of a variety of nucleic acid-based methods for rapid and sensitive detection of food-associated pathogenic bacteria. Techniques such as polymerase chain reaction have greatly expedited the process of pathogen detection and have in some cases replaced traditional methods for bacterial enumeration in food. Conventional PCR, albeit sensitive and specific under optimized conditions, obligates the user to employ agarose gel electrophoresis as the means for endpoint analysis following sample processing. For the last few years, a variety of real-time PCR chemistries and detection instruments have appeared on the market, and many of these lend themselves to applications in food microbiology. These approaches afford a user the ability to amplify DNA or RNA, as well as detect and confirm target sequence identity in a closed-tube format with the use of a variety of fluorophores, labeled probes, or both, without the need to run gels. Such real-time chemistries also offer greater sensitivity than traditional gel visualization and can be semiquantitative and multiplexed depending on the specific experimental objectives. This review emphasizes the current systems available for real-time PCR-based pathogen detection, the basic mechanisms and requirements for each, and the prospects for development over the next few years in the food industry.

  9. Nucleic acid-based vaccines targeting respiratory syncytial virus: Delivering the goods.

    Science.gov (United States)

    Smith, Trevor R F; Schultheis, Katherine; Broderick, Kate E

    2017-11-02

    Respiratory syncytial virus (RSV) is a massive medical burden on a global scale. Infants, children and the elderly represent the vulnerable populations. Currently there is no approved vaccine to protect against the disease. Vaccine development has been hindered by several factors including vaccine enhanced disease (VED) associated with formalin-inactivated RSV vaccines, inability of target populations to raise protective immune responses after vaccination or natural viral infection, and a lack of consensus concerning the most appropriate virus-associated target antigen. However, with recent advances in the molecular understanding of the virus, and design of highly characterized vaccines with enhanced immunogenicity there is new belief a RSV vaccine is possible. One promising approach is nucleic acid-based vaccinology. Both DNA and mRNA RSV vaccines are showing promising results in clinically relevant animal models, supporting their transition into humans. Here we will discuss this strategy to target RSV, and the ongoing studies to advance the nucleic acid vaccine platform as a viable option to protect vulnerable populations from this important disease.

  10. Potentiometric studies of acid-base interactions in substituted 4-nitropyridine N-oxide systems

    International Nuclear Information System (INIS)

    Gurzynski, Lukasz; Puszko, Aniela; Ostrzechowska, Agnieszka; Makowski, Mariusz; Chmurzynski, Lech

    2006-01-01

    (Acid+base) equilibrium constants, involving the acidity (pK a AC ) and cationic homoconjugation constants (in the form of lgK BHB + AC ), have been determined by the potentiometric method in 13 systems formed by substituted 4-nitropyridine N-oxides in the polar aprotic solvent, acetone (AC). The derivatives covered a wide range of proton-acceptor properties and inherent diversified tendencies towards formation of hydrogen-bonded homocomplexed cations. In addition, the constant values (expressed as pK a AN andlgK BHB + AN ) for two of the systems studied, N-oxides of 2-methylamino- and 2-ethylamino-4-nitropyridine, were determined in acetonitrile (AN). The acidity constants in the non-aqueous media studied have been found to change in line with their substituent effects and the sequence of acidity changes in water. The values of the cationic homoconjugation constants increased with increasing basicity of the N-oxides and decreased with increasing solvent basicity

  11. Calculating acid-base and oxygenation status during COPD exacerbation using mathematically arterialised venous blood

    DEFF Research Database (Denmark)

    Rees, Stephen Edward; Rychwicka-Kielek, Beate A; Andersen, Bjarne F

    2012-01-01

    Abstract Background: Repeated arterial puncture is painful. A mathematical method exists for transforming peripheral venous pH, PCO2 and PO2 to arterial eliminating the need for arterial sampling. This study evaluates this method to monitor acid-base and oxygenation during admission...... for exacerbation of chronic obstructive pulmonary disease (COPD). Methods: Simultaneous arterial and peripheral venous blood was analysed. Venous values were used to calculate arterial pH, PCO2 and PO2, with these compared to measured values using Bland-Altman analysis and scatter plots. Calculated values of PO2......H, PCO2 and PO2 were 7.432±0.047, 6.8±1.7 kPa and 9.2±1.5 kPa, respectively. Calculated and measured arterial pH and PCO2 agreed well, differences having small bias and SD (0.000±0.022 pH, -0.06±0.50 kPa PCO2), significantly better than venous blood alone. Calculated PO2 obeyed the clinical rules...

  12. Solid-contact potentiometric sensor for ascorbic acid based on cobalt phthalocyanine nanoparticles as ionophore.

    Science.gov (United States)

    Wang, Kun; Xu, Jing-Juan; Tang, Kai-Shi; Chen, Hong-Yuan

    2005-10-15

    A novel solid-contact potentiometric sensor for ascorbic acid based on cobalt phthalocyanine nanoparticles (NanoCoPc) as ionophore was fabricated without any need of auxiliary materials (such as membrane matrix, plasticizer, and other additives). The electrode was prepared by simple drop-coating NanoCoPc colloid on the surface of a glassy carbon electrode. A smooth, bright and blue thin film was strongly attached on the surface of the glassy carbon electrode. The electrode showed high selectivity for ascorbic acid, as compared with many common anions. The influences of the amount of NanoCoPc at the electrode surface and pH on the response characteristics of the electrode were investigated. To overcome the instability of the formal potential of the coated wire electrode, a novel electrochemical pretreatment method was proposed for the potentiometric sensor based on redox mechanism. This resulting sensor demonstrates potentiometric response over a wide linear range of ascorbic acid concentration (5.5 x 10(-7) to 5.5 x 10(-2)M) with a fast response (determination of practical samples.

  13. Biological and surface-active properties of double-chain cationic amino acid-based surfactants.

    Science.gov (United States)

    Greber, Katarzyna E; Dawgul, Małgorzata; Kamysz, Wojciech; Sawicki, Wiesław; Łukasiak, Jerzy

    2014-08-01

    Cationic amino acid-based surfactants were synthesized via solid phase peptide synthesis and terminal acylation of their α and ε positions with saturated fatty acids. Five new lipopeptides, N-α-acyl-N-ε-acyl lysine analogues, were obtained. Minimum inhibitory concentration and minimum bactericidal (fungicidal) concentration were determined on reference strains of bacteria and fungi to evaluate the antimicrobial activity of the lipopeptides. Toxicity to eukaryotic cells was examined via determination of the haemolytic activities. The surface-active properties of these compounds were evaluated by measuring the surface tension and formation of micelles as a function of concentration in aqueous solution. The cationic surfactants demonstrated diverse antibacterial activities dependent on the length of the fatty acid chain. Gram-negative bacteria and fungi showed a higher resistance than Gram-positive bacterial strains. It was found that the haemolytic activities were also chain length-dependent values. The surface-active properties showed a linear correlation between the alkyl chain length and the critical micelle concentration.

  14. Potentiometric studies of acid-base interactions in substituted 4-nitropyridine N-oxide systems

    Energy Technology Data Exchange (ETDEWEB)

    Gurzynski, Lukasz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Puszko, Aniela [Department of Organic Chemistry, School of Economics, Wroclaw (Poland); Ostrzechowska, Agnieszka [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Makowski, Mariusz [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland); Chmurzynski, Lech [Department of General Chemistry, University of Gdansk, Sobieskiego 18, 80-952 Gdansk (Poland)]. E-mail: lech@chem.univ.gda.pl

    2006-05-15

    (Acid+base) equilibrium constants, involving the acidity (pK{sub a}{sup AC}) and cationic homoconjugation constants (in the form of lgK{sub BHB{sup +}}{sup AC}), have been determined by the potentiometric method in 13 systems formed by substituted 4-nitropyridine N-oxides in the polar aprotic solvent, acetone (AC). The derivatives covered a wide range of proton-acceptor properties and inherent diversified tendencies towards formation of hydrogen-bonded homocomplexed cations. In addition, the constant values (expressed as pK{sub a}{sup AN}andlgK{sub BHB{sup +}}{sup AN}) for two of the systems studied, N-oxides of 2-methylamino- and 2-ethylamino-4-nitropyridine, were determined in acetonitrile (AN). The acidity constants in the non-aqueous media studied have been found to change in line with their substituent effects and the sequence of acidity changes in water. The values of the cationic homoconjugation constants increased with increasing basicity of the N-oxides and decreased with increasing solvent basicity.

  15. Electrospin-coating of nitrocellulose membrane enhances sensitivity in nucleic acid-based lateral flow assay.

    Science.gov (United States)

    Yew, Chee-Hong Takahiro; Azari, Pedram; Choi, Jane Ru; Li, Fei; Pingguan-Murphy, Belinda

    2018-06-07

    Point-of-care biosensors are important tools developed to aid medical diagnosis and testing, food safety and environmental monitoring. Paper-based biosensors, especially nucleic acid-based lateral flow assays (LFA), are affordable, simple to produce and easy to use in remote settings. However, the sensitivity of such assays to infectious diseases has always been a restrictive challenge. Here, we have successfully electrospun polycaprolactone (PCL) on nitrocellulose (NC) membrane to form a hydrophobic coating to reduce the flow rate and increase the interaction rate between the targets and gold nanoparticles-detecting probes conjugates, resulting in the binding of more complexes to the capture probes. With this approach, the sensitivity of the PCL electrospin-coated test strip has been increased by approximately ten-fold as compared to the unmodified test strip. As a proof of concept, this approach holds great potential for sensitive detection of targets at point-of-care testing. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. American Society of Nephrology Quiz and Questionnaire 2015: Electrolytes and Acid-Base Disorders.

    Science.gov (United States)

    Rosner, Mitchell H; Perazella, Mark A; Choi, Michael J

    2016-04-07

    The Nephrology Quiz and Questionnaire remains an extremely popular session for attendees of the annual Kidney Week meeting of the American Society of Nephrology. During the 2015 meeting the conference hall was once again overflowing with eager quiz participants. Topics covered by the experts included electrolyte and acid-base disorders, glomerular disease, end-stage renal disease and dialysis, and kidney transplantation. Complex cases representing each of these categories together with single-best-answer questions were prepared and submitted by the panel of experts. Before the meeting, training program directors of nephrology fellowship programs and nephrology fellows in the United States answered the questions through an internet-based questionnaire. During the live session members of the audience tested their knowledge and judgment on the same series of case-oriented questions in a quiz. The audience compared their answers in real time using a cell-phone app containing the answers of the nephrology fellows and training program directors. The results of the online questionnaire were displayed, and then the quiz answers were discussed. As always, the audience, lecturers, and moderators enjoyed this highly educational session. This article recapitulates the session and reproduces selected content of educational value for theClinical Journal of the American Society of Nephrologyreaders. Enjoy the clinical cases and expert discussions. Copyright © 2016 by the American Society of Nephrology.

  17. [Acid-base catalysis of chiral Pd complexes: development of novel asymmetric reactions].

    Science.gov (United States)

    Hamashima, Yoshitaka

    2005-10-01

    Using a unique character of the chiral palladium complexes 1 and 2, several types of novel catalytic asymmetric reactions have been developed. In contrast to the conventional Pd(0)-catalyzed reactions, these complexes function as an acid-base catalyst. Thus active methine compounds were activated to form chiral palladium enolates, which underwent the enantioselective Michael reaction and Mannich-type reaction with up to 99% ee. Interestingly, these palladium enolates acted cooperatively with a strong protic acid activating the electrophiles, formed concomitantly during the formation of the enolates, whereby the C-C bond-forming reaction was promoted. In addition, this palladium enolate chemistry was also applicable to the electrophilic asymmetric fluorination reactions, and thus various carbonyl compounds including beta-ketoesters, beta-ketophosphonates, and oxindoles were fluorinated in a highly enantioselective manner (up to 98% ee). It is advantageous that these reactions were carried out in environmentally friendly alcoholic solvents such as ethanol, and exclusion of air and moisture is not necessary.

  18. New URJC-1 Material with Remarkable Stability and Acid-Base Catalytic Properties

    Directory of Open Access Journals (Sweden)

    Pedro Leo

    2016-02-01

    Full Text Available Emerging new metal-organic structures with tunable physicochemical properties is an exciting research field for diverse applications. In this work, a novel metal-organic framework Cu(HIT(DMF0.5, named URJC-1, with a three-dimensional non-interpenetrated utp topological network, has been synthesized. This material exhibits a microporous structure with unsaturated copper centers and imidazole–tetrazole linkages that provide accessible Lewis acid/base sites. These features make URJC-1 an exceptional candidate for catalytic application in acid and base reactions of interest in fine chemistry. The URJC-1 material also displays a noteworthy thermal and chemical stability in different organic solvents of different polarity and boiling water. Its catalytic activity was evaluated in acid-catalyzed Friedel–Crafts acylation of anisole with acetyl chloride and base-catalyzed Knoevenagel condensation of benzaldehyde with malononitrile. In both cases, URJC-1 material showed very good performance, better than other metal organic frameworks and conventional catalysts. In addition, a remarkable structural stability was proven after several consecutive reaction cycles.

  19. Effective and Reversible Switching of Emulsions by an Acid/Base-Mediated Redox Reaction.

    Science.gov (United States)

    Zhang, Yuandi; Chen, Hui; Liu, Xuefeng; Zhang, Yongmin; Fang, Yun; Qin, Zhirong

    2016-12-27

    To develop a fast, effective, and reversible strategy for phase separation and re-emulsification of the surfactant-based emulsions, a strategy for using acid/base-mediated redox reactions was established to switch the emulsions formed from a redox-responsive anionic surfactant of potassium dodecyl seleninate (C 12 SeO 2 K). Upon acidification, C 12 SeO 2 K was reduced by KI to give didodecyl diselenide (C 12 Se) 2 , a state of almost no surface or interfacial activity; upon basification, (C 12 Se) 2 was oxidized by I 2 to give C 12 SeO 2 K again. The fractional conversion of C 12 SeO 2 K in the reversible switching processes was close to 100%. Consequently, an unusually large change in interfacial tension (ΔIFT) as high as ∼27.1 mN m -1 was obtained at a wider concentration range starting from the critical micelle concentration of C 12 SeO 2 K; the highest IFT at the oil-water interface was obtained after an almost complete switch-off, giving an oil-aqueous solution interface very similar to that without any emulsifiers, which leads to the effective and fast phase separation of the C 12 SeO 2 K-based switchable emulsions.

  20. Acid-base changes in canine neonates following normal birth or dystocia.

    Science.gov (United States)

    Lúcio, C F; Silva, L C G; Rodrigues, J A; Veiga, G A L; Vannucchi, C I

    2009-07-01

    There are limited data concerning blood gas parameters in neonatal dogs. Knowledge of the normal physiology may facilitate effective therapeutic intervention and potentially reduce neonatal mortality. This study examined acid-base parameters in pups born at normal parturition (n = 27) compared with those born after obstetrical assistance or caesarean operation (n = 13) and those born following oxytocin (OXY) administration for treatment of uterine inertia (n = 11). Pups were subjected to an objective scoring method of neonatal health adapted from use in humans (the Apgar score) at birth and again at 5 and 60 min after birth. Venous blood samples were collected at 5 and 60 min after birth for evaluation of blood gas parameters. At birth, all pups had low Apgar scores and a mixed acidosis. The base excess was lowest for pups delivered after OXY administration. The Apgar score improved for all pups after 5 min of birth and there was an improvement in carbon dioxide tension, base excess and venous blood pH at 1 h, although in all pups a metabolic acidosis persisted. These data provide an important insight into neonatal physiology and the variability of blood gas parameters in pups born at normal and abnormal parturition and provide the basis for clinical decision making following dystocia.

  1. The Use of Commercial Non-Hazardous Air Pollutant Monomers to Optimize the Properties of Fatty Acid-Based Resins

    Science.gov (United States)

    2009-05-01

    It was found that cyclohexyl methacrylate (CHMA) was the most effective reactive diluent in replacing methacrylated lauric acid (MLau) because it...The reaction of glycidyl methacrylate and lauric acid to produce the MLau monomer... acid -based monomers to be used as the reactive diluent in VE resins (9, 10). Figure 1 depicts the synthetic route used to form methacrylated lauric

  2. Physiologic and acid-base measures of gopher snakes during ketamine or halothane-nitrous oxide anesthesia.

    Science.gov (United States)

    Custer, R S; Bush, M

    1980-11-01

    Arterial acid-base and selected physiologic measures of gopher snakes (Pituophis melanoleucus catenifer) during ketamine or halothane-nitrous oxide anesthesia were compared with base-line values. During ketamine anesthesia, significant decreases in pH and HCO-3 concentrations indicated acid-base states of uncompensated metabolic acidosis. In contrast, halothane-nitrous oxide anesthesia induced acidosis of respiratory origin, through a significant depression in respiratory rate. In addition to the conventional measures, the OH-/H+ ratios and the alpha-imidazole (alpha IM) values were calculated to assess acid-base status during anesthesia. Values for both factors decreased significantly during both ketamine and halothane-nitrous oxide anesthesia. Where H+ concentrations nearly doubled, the decline in the OH-/H+ ratio exceeded 70% and the alpha IM decreased less than 20%. It was concluded that these 2 factors may be helpful in evaluation of the acid-base status of ectothermic animals when normal values for the conventional measures of pH and pCO2 are not available for comparison.

  3. EFFECT OF CASEIN-BASED SEMISYNTHETIC FOOD ON RENAL ACID EXCRETION AND ACID-BASE STATE OF BLOOD IN DOGS

    NARCIS (Netherlands)

    ZIJLSTRA, WG; LANGBROEK, AJM; KRAAN, J; RISPENS, P; NIJMEIJER, A

    1995-01-01

    Urinary acid excretion and blood acid-base stare were determined in dogs fed a casein-based semi-synthetic food (SSF), to which different amounts of salts had been added, in comparison with feeding normal dog food. Net acid excretion (NAE) and inorganic acid excretion (IAE) increased during SSF

  4. How are the Concepts and Theories of Acid-Base Reactions Presented? Chemistry in Textbooks and as Presented by Teachers

    Science.gov (United States)

    Furio-Mas, Carlos; Calatayud, Maria Luisa; Guisasola, Jenaro; Furio-Gomez, Cristina

    2005-01-01

    This paper investigates the views of science and scientific activity that can be found in chemistry textbooks and heard from teachers when acid-base reactions are introduced to grade 12 and university chemistry students. First, the main macroscopic and microscopic conceptual models are developed. Second, we attempt to show how the existence of…

  5. Collaborative Teaching Strategies Lead to Retention of Skills in Acid-Base Physiology: A 2-Yr Follow-Up Study

    Science.gov (United States)

    Hartmann, Jacob P.; Toksvang, Linea Natalie; Berg, Ronan M. G.

    2015-01-01

    A basic understanding of acid-base physiology is critical for the correct assessment of arterial blood gases in the clinical setting. In this context, collaborative teaching strategies in the undergraduate classroom setting may be useful, since it has been reported to enhance both transfer and retention of learned material in a time-efficient…

  6. Using Two-Tier Test to Identify Primary Students' Conceptual Understanding and Alternative Conceptions in Acid Base

    Science.gov (United States)

    Bayrak, Beyza Karadeniz

    2013-01-01

    The purpose of this study was to identify primary students' conceptual understanding and alternative conceptions in acid-base. For this reason, a 15 items two-tier multiple choice test administered 56 eighth grade students in spring semester 2009-2010. Data for this study were collected using a conceptual understanding scale prepared to include…

  7. Assembling and Using an LED-Based Detector to Monitor Absorbance Changes during Acid-Base Titrations

    Science.gov (United States)

    Santos, Willy G.; Cavalheiro, E´der T. G.

    2015-01-01

    A simple photometric assembly based in an LED as a light source and a photodiode as a detector is proposed in order to follow the absorbance changes as a function of the titrant volume added during the course of acid-base titrations in the presence of a suitable visual indicator. The simplicity and low cost of the electronic device allow the…

  8. On the Prevalence of Alternative Conceptions on Acid-Base Chemistry among Secondary Students: Insights from Cognitive and Confidence Measures

    Science.gov (United States)

    Hoe, Kai Yee; Subramaniam, R.

    2016-01-01

    This study presents an analysis of alternative conceptions (ACs) on acid--base chemistry harbored by grade 9 students in Singapore. The ACs were obtained by the development and validation of a 4-tier diagnostic instrument. It is among the very few studies in the science education literature that have focused on examining results based also on…

  9. The relationship between odd- and branched-chain fatty acids and microbial nucleic acid bases in rumen.

    Science.gov (United States)

    Liu, Keyuan; Hao, Xiaoyan; Li, Yang; Luo, Guobin; Zhang, Yonggen; Xin, Hangshu

    2017-11-01

    This study aims to identify the relationship between odd- and branched-chain fatty acids (OBCFAs) and microbial nucleic acid bases in the rumen, and to establish a model to accurately predict microbial protein flow by using OBCFA. To develop the regression equations, data on the rumen contents of individual cows were obtained from 2 feeding experiments. In the first experiment, 3 rumen-fistulated dry dairy cows arranged in a 3×3 Latin square were fed diets of differing forage to concentration ratios (F:C). The second experiment consisted of 9 lactating Holstein dairy cows of similar body weights at the same stage of pregnancy. For each lactation stage, 3 cows with similar milk production were selected. The rumen contents were sampled at 4 time points of every two hours after morning feeding 6 h, and then to analyse the concentrations of OBCFA and microbial nucleic acid bases in the rumen samples. The ruminal bacteria nucleic acid bases were significantly influenced by feeding diets of differing forge to concentration ratios and lactation stages of dairy cows (pacids and C15:0 isomers, strongly correlated with the microbial nucleic acid bases in the rumen (pacid bases established by ruminal OBCFAs contents showed a good predictive capacity, as indicated by reasonably low standard errors and high R-squared values. This finding suggests that the rumen OBCFA composition could be used as an internal marker of rumen microbial matter.

  10. Using Laboratory Activities Enhanced with Concept Cartoons to Support Progression in Students' Understanding of Acid-Base Concepts

    Science.gov (United States)

    Ozmen, Haluk; Demircioglu, Gokhan; Burhan, Yasemin; Naseriazar, Akbar; Demircioglu, Hulya

    2012-01-01

    The aim of this study is to examine the effectiveness of an intervention based on a series of laboratory activities enhanced with concept cartoons. The purpose of the intervention was to enhance students' understanding of acid-base chemistry for eight grade students' from two classes in a Turkish primary school. A pretest-posttest non-equivalent…

  11. Ethylenediamine-functionalized graphene oxide incorporated acid-base ion exchange membranes for vanadium redox flow battery

    International Nuclear Information System (INIS)

    Liu, Shuai; Li, Dan; Wang, Lihua; Yang, Haijun; Han, Xutong; Liu, Biqian

    2017-01-01

    Highlights: • Ethylenediamine functionalized graphene oxide. • Layered structure of functionalized graphene oxide block vanadium ions crossover. • Protonated N-containing groups suppress vanadium ions permeation. • Ion transport channels are narrowed by electrostatic interactions. • Vanadium crossover decreased due to enhanced Donnan effect and special structure. - Abstract: As a promising large-scale energy storage battery, vanadium redox flow battery (VRFB) is urgently needed to develop cost-effective membranes with excellent performance. Novel acid-base ion exchange membranes (IEMs) are fabricated based on sulfonated poly(ether ether ketone) (SPEEK) matrix and modified graphene oxide (GO) by solution blending. N-based functionalized graphene oxide (GO-NH 2 ) is fabricated by grafting ethylenediamine onto the edge of GO via a facile method. On one hand, the impermeable layered structures effectively block ion transport pathway to restrain vanadium ions crossover. On the other hand, acid-base pairs form between −SO 3 − groups and N-based groups on the edge of GO nanosheets, which not only suppress vanadium ions contamination but also provide a narrow pathway for proton migration. The structure is beneficial for achieving an intrinsic balance between conductivity and permeability. By altering amounts of GO-NH 2 , a sequence of acid-base IEMs are characterized in detail. The single cells assembled with acid-base IEMs show self-discharge time for 160 h, capacity retention 92% after 100 cycle, coulombic efficiency 97.2% and energy efficiency 89.5%. All data indicate that acid-base IEMs have promising prospects for VRFB applications.

  12. Critical evaluation of dipolar, acid-base and charge interactions I. Electron displacement within and between molecules, liquids and semiconductors.

    Science.gov (United States)

    Rosenholm, Jarl B

    2017-09-01

    Specific dipolar, acid-base and charge interactions involve electron displacements. For atoms, single bonds and molecules electron displacement is characterized by electronic potential, absolute hardness, electronegativity and electron gap. In addition, dissociation, bonding, atomization, formation, ionization, affinity and lattice enthalpies are required to quantify the electron displacement in solids. Semiconductors are characterized by valence and conduction band energies, electron gaps and average Fermi energies which in turn determine Galvani potentials of the bulk, space charge layer and surface states. Electron displacement due to interaction between (probe) molecules, liquids and solids are characterized by parameters such as Hamaker constant, solubility parameter, exchange energy density, surface tension, work of adhesion and immersion. They are determined from permittivity, refractive index, enthalpy of vaporization, molar volume, surface pressure and contact angle. Moreover, acidic and basic probes may form adducts which are adsorbed on target substrates in order to establish an indirect measure of polarity, acidity, basicity or hydrogen bonding. Acidic acceptor numbers (AN), basic donor numbers (DN), acidic and basic "electrostatic" (E) and "covalent" (C) parameters determined by enthalpy of adduct formation are considered as general acid-base scales. However, the formal grounds for assignments as dispersive, Lifshitz-van der Waals, polar, acid, base and hydrogen bond interactions are inconsistent. Although correlations are found no of the parameters are mutually fully compatible and moreover the enthalpies of acid-base interaction do not correspond to free energies. In this review the foundations of different acid-base parameters relating to electron displacement within and between (probe) molecules, liquids and (semiconducting) solids are thoroughly investigated and their mutual relationships are evaluated. Copyright © 2017 Elsevier B.V. All rights

  13. Acid-Base and Plasma Biochemical Changes Using Crystalloid Fluids in Stranded Juvenile Loggerhead Sea Turtles (Caretta caretta).

    Science.gov (United States)

    Camacho, María; Quintana, María Del Pino; Calabuig, Pascual; Luzardo, Octavio P; Boada, Luis D; Zumbado, Manuel; Orós, Jorge

    2015-01-01

    The aim of this study was to compare the efficacy and effects on acid-base and electrolyte status of several crystalloid fluids in 57 stranded juvenile loggerhead turtles. Within a rehabilitation program four different crystalloid fluids were administered (0.9% Na Cl solution; 5% dextrose + 0.9% Na Cl solutions 1:1; 0.9% Na Cl + lactated Ringer's solutions 1:1; lactated Ringer's solution). Crystalloid fluids were intracoelomically administered during three days (20 ml/kg/day). Animals were sampled at three different moments: Upon admission for evaluating the type of acid-base or biochemical disorder, post-fluid therapy treatment for controlling the evolution of the disorder, and post-recovery period for obtaining the baseline values for rehabilitated loggerhead turtles. Each sample was analyzed with a portable electronic blood analyzer for pH, pO2, pCO2, lactate, sodium, potassium, chloride, glucose, and BUN concentration. Admission and post-fluid therapy treatment values were compared with those obtained for each turtle immediately before release. The highest percentage of acid-base recovery and electrolyte balance was observed in turtles treated with mixed saline-lactated Ringer's solution (63.6%), followed by turtles treated with physiological saline solution (55%), lactated Ringer's solution (33.3%), and dextrose-saline solutions (10%). Most turtles treated with lactated Ringer's solution had lower lactate concentrations compared with their initial values; however, 66.6% of turtles treated with lactated Ringer's solution had metabolic alkalosis after therapy. Significant higher concentrations of glucose were detected after saline-dextrose administration compared with all the remaining fluids. This is the first study evaluating the effects of several crystalloid fluids on the acid-base status and plasma biochemical values in stranded loggerhead sea turtles. Reference convalescent venous blood gas, acid-base, and plasma biochemical values, useful for veterinary

  14. The relationship between odd- and branched-chain fatty acids and microbial nucleic acid bases in rumen

    Directory of Open Access Journals (Sweden)

    Keyuan Liu

    2017-11-01

    Full Text Available Objective This study aims to identify the relationship between odd- and branched-chain fatty acids (OBCFAs and microbial nucleic acid bases in the rumen, and to establish a model to accurately predict microbial protein flow by using OBCFA. Methods To develop the regression equations, data on the rumen contents of individual cows were obtained from 2 feeding experiments. In the first experiment, 3 rumen-fistulated dry dairy cows arranged in a 3×3 Latin square were fed diets of differing forage to concentration ratios (F:C. The second experiment consisted of 9 lactating Holstein dairy cows of similar body weights at the same stage of pregnancy. For each lactation stage, 3 cows with similar milk production were selected. The rumen contents were sampled at 4 time points of every two hours after morning feeding 6 h, and then to analyse the concentrations of OBCFA and microbial nucleic acid bases in the rumen samples. Results The ruminal bacteria nucleic acid bases were significantly influenced by feeding diets of differing forge to concentration ratios and lactation stages of dairy cows (p<0.05. The concentrations of OBCFAs, especially odd-chain fatty acids and C15:0 isomers, strongly correlated with the microbial nucleic acid bases in the rumen (p<0.05. The equations of ruminal microbial nucleic acid bases established by ruminal OBCFAs contents showed a good predictive capacity, as indicated by reasonably low standard errors and high R-squared values. Conclusion This finding suggests that the rumen OBCFA composition could be used as an internal marker of rumen microbial matter.

  15. Correlating multidimensional fetal heart rate variability analysis with acid-base balance at birth.

    Science.gov (United States)

    Frasch, Martin G; Xu, Yawen; Stampalija, Tamara; Durosier, Lucien D; Herry, Christophe; Wang, Xiaogang; Casati, Daniela; Seely, Andrew Je; Alfirevic, Zarko; Gao, Xin; Ferrazzi, Enrico

    2014-12-01

    Fetal monitoring during labour currently fails to accurately detect acidemia. We developed a method to assess the multidimensional properties of fetal heart rate variability (fHRV) from trans-abdominal fetal electrocardiogram (fECG) during labour. We aimed to assess this novel bioinformatics approach for correlation between fHRV and neonatal pH or base excess (BE) at birth.We enrolled a prospective pilot cohort of uncomplicated singleton pregnancies at 38-42 weeks' gestation in Milan, Italy, and Liverpool, UK. Fetal monitoring was performed by standard cardiotocography. Simultaneously, with fECG (high sampling frequency) was recorded. To ensure clinician blinding, fECG information was not displayed. Data from the last 60 min preceding onset of second-stage labour were analyzed using clinically validated continuous individualized multiorgan variability analysis (CIMVA) software in 5 min overlapping windows. CIMVA allows simultaneous calculation of 101 fHRV measures across five fHRV signal analysis domains. We validated our mathematical prediction model internally with 80:20 cross-validation split, comparing results to cord pH and BE at birth.The cohort consisted of 60 women with neonatal pH values at birth ranging from 7.44 to 6.99 and BE from -0.3 to -18.7 mmol L(-1). Our model predicted pH from 30 fHRV measures (R(2) = 0.90, P base balance at birth. Further refinement and validation in larger cohorts are needed. These new measurements of fHRV might offer a new opportunity to predict fetal acid-base balance at birth.

  16. Renal acid-base physiology in marine teleost, the long-horned sculpin (Myoxocephalus octodecimspinosus).

    Science.gov (United States)

    Maren, T H; Fine, A; Swenson, E R; Rothman, D

    1992-07-01

    We have sought to define urinary acid-base excretion in the marine teleost using the long-horned sculpin, Myoxocephalus octodecimspinosus. Urine flow (1.7 ml.h-1.kg-1) is relatively high, and glomerular filtration rate is very low (2.9 ml.h-1.kg-1). The urine-to-plasma ratio of inulin is 2. Renal clearance of p-aminohippurate is very high (108 ml.h-1.kg-1); phosphate and divalent cations are also secreted. In this framework we found urinary pH to average 6.6, but infusion of acid or alkali elicited a pH range of 6.1-7.8. Untreated fish may also have alkaline urine; so it is not surprising that precipitates of calcium or magnesium phosphate are sometimes found in bladder. These are of fine sandy quality and never cause blockage. Infusion of buffer (imidazole) increased the concentration of titratable acid 11-fold and output 2.5-fold. Carbonic anhydrase inhibitors had no effect on any urinary component, and histochemical studies revealed that cytoplasm and membranes did not yield the specific cobalt stain for the enzyme. An alkaline load (NaHCO3) is rapidly dissipated by gill excretion, mediated in part by carbonic anhydrase. An acid load (HCl) is rapidly dissipated by gill excretion, not dependent on carbonic anhydrase, and some renal excretion. Comparison and contrast of the low rates of HCO3- reabsorption in the marine teleost (and elasmobranch) with those of mammals suggest strongly that renal carbonic anhydrase evolved in connection with these high reabsorptive rates beginning in freshwater fish and continuing through amphibia and birds.

  17. Modelling the acid/base 1H NMR chemical shift limits of metabolites in human urine.

    Science.gov (United States)

    Tredwell, Gregory D; Bundy, Jacob G; De Iorio, Maria; Ebbels, Timothy M D

    2016-01-01

    Despite the use of buffering agents the 1 H NMR spectra of biofluid samples in metabolic profiling investigations typically suffer from extensive peak frequency shifting between spectra. These chemical shift changes are mainly due to differences in pH and divalent metal ion concentrations between the samples. This frequency shifting results in a correspondence problem: it can be hard to register the same peak as belonging to the same molecule across multiple samples. The problem is especially acute for urine, which can have a wide range of ionic concentrations between different samples. To investigate the acid, base and metal ion dependent 1 H NMR chemical shift variations and limits of the main metabolites in a complex biological mixture. Urine samples from five different individuals were collected and pooled, and pre-treated with Chelex-100 ion exchange resin. Urine samples were either treated with either HCl or NaOH, or were supplemented with various concentrations of CaCl 2 , MgCl 2 , NaCl or KCl, and their 1 H NMR spectra were acquired. Nonlinear fitting was used to derive acid dissociation constants and acid and base chemical shift limits for peaks from 33 identified metabolites. Peak pH titration curves for a further 65 unidentified peaks were also obtained for future reference. Furthermore, the peak variations induced by the main metal ions present in urine, Na + , K + , Ca 2+ and Mg 2+ , were also measured. These data will be a valuable resource for 1 H NMR metabolite profiling experiments and for the development of automated metabolite alignment and identification algorithms for 1 H NMR spectra.

  18. The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran

    Directory of Open Access Journals (Sweden)

    Jokić Anja B.

    2013-01-01

    Full Text Available The application of the hydrogen-palladium electrode (H2/Pd as the indicator electrode for the determination of relative acidity scale (Es, mV of tetrahydrofuran (THF and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH, which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, α-naphthol and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + ftalic acid were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. [Projekat Ministarstva nauke Republike Srbije, br.172051

  19. Inhibition of Listeria monocytogenes by propionic acid-based ingredients in cured deli-style Turkey.

    Science.gov (United States)

    Glass, Kathleen A; McDonnell, Lindsey M; Von Tayson, Roxanne; Wanless, Brandon; Badvela, Mani

    2013-12-01

    Listeria monocytogenes growth can be controlled on ready-to-eat meats through the incorporation of antimicrobial ingredients into the formulation or by postlethality kill steps. However, alternate approaches are needed to provide options that reduce sodium content but maintain protection against pathogen growth in meats after slicing. The objective of this study was to determine the inhibition of L. monocytogenes by propionic acid-based ingredients in high-moisture, cured turkey stored at 4 or 7°C. Six formulations of sliced, cured (120 ppm of NaNO2 ), deli-style turkey were tested, including control without antimicrobials, 3.2% lactate-diacetate blend (LD), 0.4% of a liquid propionate-benzoate-containing ingredient, or 0.3, 0.4, and 0.5% of a liquid propionate-containing ingredient. Products were inoculated with 5 log CFU L. monocytogenes per 100-g package (3 log CFU/ml rinsate), vacuum-sealed, and stored at 4 or 7°C for up to 12 weeks; and populations were enumerated by plating on modified Oxford agar. As expected, the control without antimicrobials supported rapid growth, with >2 log average per ml rinsate increase within 4 weeks of storage at 4°C, whereas growth was observed at 6 weeks for the LD treatment. For both replicate trials, all treatments that contained liquid propionate or propionate-benzoate limited L. monocytogenes growth to an increase of 1-log increase) was observed in individual samples for all propionate-containing treatments at weeks 10, 11, and 12. As expected, L. monocytogenes grew more rapidly when products were stored at 7°C, but trends in relative inhibition were similar to those observed at 4°C. These results verify that propionate-based ingredients inhibit growth of L. monocytogenes on sliced, high-moisture, cured turkey and can be considered as an alternative to reduce sodium-based salts while maintaining food safety.

  20. [Nutrition, acid-base metabolism, cation-anion difference and total base balance in humans].

    Science.gov (United States)

    Mioni, R; Sala, P; Mioni, G

    2008-01-01

    The relationship between dietary intake and acid-base metabolism has been investigated in the past by means of the inorganic cation-anion difference (C(+)(nm)-A(-)(nm)) method based on dietary ash-acidity titration after the oxidative combustion of food samples. Besides the inorganic components of TA (A(-)(nm)-C(+)(nm)), which are under renal control, there are also metabolizable components (A(-)(nm)-C(+)(nm)) of TA, which are under the control of the intermediate metabolism. The whole body base balance, NBb(W), is obtained only by the application of C(+)(nm)-A(-)(nm) to food, feces and urine, while the metabolizable component (A(-)(nm)-C(+)(nm)) is disregarded. A novel method has been subsequently suggested to calculate the net balance of fixed acid, made up by the difference between the input of net endogenous acid production: NEAP = SO(4)(2-)+A(-)(m)-(C(+)(nm)-A(-)(nm)), and the output of net acid excretion: NAE = TA + NH(4)(+) - HCO(3)(-). This approach has been criticized because 1) it includes metabolizable acids, whose production cannot be measured independently; 2) the specific control of metabolizable acid and base has been incorrectly attributed to the kidney; 3) the inclusion of A-m in the balance input generates an acid overload; 4) the object of measurement in making up a balance has to be the same, a condition not fulfilled as NEAP is different from NAE. Lastly, by rearranging the net balance of the acid equation, the balance of nonmetabolizable acid equation is obtained. Therefore, any discrepancy between these two equations is due to the inaccuracy in the urine measurement of metabolizable cations and/or anions.

  1. Acid base, electrolyte, glucose, and lactate values during cardiopulmonary resuscitation in dogs and cats.

    Science.gov (United States)

    Hopper, Kate; Borchers, Angela; Epstein, Steven E

    2014-01-01

    To report acid base, electrolyte, glucose, and lactate values collected during or immediately after cardiopulmonary resuscitation (CPR) in dogs and cats. Retrospective study. University Teaching Hospital. Thirty-two dogs and 10 cats. None. Blood gas, electrolyte, glucose, and lactate values measured during CPR or within 5 minutes of return of spontaneous circulation (ROSC) were retrospectively evaluated. The time of blood collection with respect to the occurrence of cardiopulmonary arrest (CPA), the initiation of CPR or ROSC was noted. Forty-two venous blood samples were analyzed, 24 collected during CPR and 18 samples were collected within 5 minutes of ROSC. Metabolic acidosis and hyperlactatemia were evident in all samples in the study while an increased PvCO2 occurred in 88% of samples collected during CPR and in 61% of samples collected following ROSC. Hyperkalemia occurred in 65% of all cases, decreased ionized calcium was evident in 18%, hypoglycemia was evident in 21% while hyperglycemia was evident in 62%. There was no significant difference in any parameter evaluated between dogs and cats during CPR. There was no significant difference of any variable measured during the first 15 minutes of CPA versus those measured more than 15 minutes following CPA. When the values measured during the first 5 minutes of ROSC were compared to those measured during CPR, the pH and PvO2 were significantly lower in the CPR group. Biochemical abnormalities including metabolic acidosis, hyperkalemia, ionized hypocalcemia, hypoglycemia, and hyperglycemia can be identified during CPR and immediately following ROSC. The therapeutic and prognostic relevance of these changes are yet to be defined and may prove to be useful to guide patient management in the future. © Veterinary Emergency and Critical Care Society 2014.

  2. Lewis Acid-Base Chemistry of 7-Azaisoindigo-Based Organic Semiconductors.

    Science.gov (United States)

    Randell, Nicholas M; Fransishyn, Kyle M; Kelly, Timothy L

    2017-07-26

    Low-band-gap organic semiconductors are important in a variety of organic electronics applications, such as organic photovoltaic devices, photodetectors, and field effect transistors. Building on our previous work, which introduced 7-azaisoindigo as an electron-deficient building block for the synthesis of donor-acceptor organic semiconductors, we demonstrate how Lewis acids can be used to further tune the energies of the frontier molecular orbitals. Coordination of a Lewis acid to the pyridinic nitrogen of 7-azaisoindigo greatly diminishes the electron density in the azaisoindigo π-system, resulting in a substantial reduction in the lowest unoccupied molecular orbital (LUMO) energy. This results in a smaller highest occupied molecular orbital-LUMO gap and shifts the lowest-energy electronic transition well into the near-infrared region. Both H + and BF 3 are shown to coordinate to azaisoindigo and affect the energy of the S 0 → S 1 transition. A combination of time-dependent density functional theory and UV/vis and 1 H NMR spectroscopic titrations reveal that when two azaisoindigo groups are present and high concentrations of acid are used, both pyridinic nitrogens bind Lewis acids. Importantly, we demonstrate that this acid-base chemistry can be carried out at the solid-vapor interface by exposing thin films of aza-substituted organic semiconductors to vapor-phase BF 3 ·Et 2 O. This suggests the possibility of using the BF 3 -bound 7-azaisoindigo-based semiconductors as n-type materials in various organic electronic applications.

  3. Acid-base characteristics of bromophenol blue-citrate buffer systems in the amorphous state.

    Science.gov (United States)

    Li, Jinjiang; Chatterjee, Koustuv; Medek, Ales; Shalaev, Evgenyi; Zografi, George

    2004-03-01

    In this study, we have examined the acid-base characteristics of various citrate buffer systems alone and in the presence of the pH indicator dye, bromophenol blue, in aqueous solution, and after lyophilization to produce amorphous material. Fourier transform Raman and solid-state nuclear magnetic resonance spectroscopy have been used to monitor the ratio of ionized to un-ionized citric acid under various conditions, as a function of initial pH in the range of 2.65-4.28. Ultraviolet-visible spectrophotometry was used to probe the extent of proton transfer of bromophenol blue in the citrate buffer systems in solution and the amorphous state. Spectroscopic studies indicated greater ionization of citric acid and bromophenol blue in solution and the solid state with increasing initial solution pH, as expected. Fourier transform Raman measurements indicated the same ratio of ionized to un-ionized citrate species in solution, frozen solution, and the amorphous state. It is shown that the ratio of species at any particular initial pH is primarily determined by the amount of sodium ion present so as to maintain electroneutrality and not necessarily to the fact that pH and pK(a) remain unchanged during freezing and freeze drying. Indeed, for bromophenol blue, the relative ultraviolet-visible intensities for ionized and un-ionized species in the amorphous sample were different from those in solution indicating that the extent of protonation of bromophenol blue was significantly lower in the solid samples. It is concluded that under certain conditions there can be significant differences in the apparent hydrogen activity of molecules in amorphous systems. Copyright 2004 Wiley-Liss, Inc. and the American Pharmacists Association

  4. Lithium increases ammonium excretion leading to altered urinary acid-base buffer composition.

    Science.gov (United States)

    Trepiccione, Francesco; Altobelli, Claudia; Capasso, Giovambattista; Christensen, Birgitte Mønster; Frische, Sebastian

    2017-11-24

    Previous reports identify a voltage dependent distal renal tubular acidosis (dRTA) secondary to lithium (Li + ) salt administration. This was based on the inability of Li + -treated patients to increase the urine-blood (U-B) pCO 2 when challenged with NaHCO 3 and, the ability of sodium neutral phosphate or Na 2 SO 4 administration to restore U-B pCO 2 in experimental animal models. The underlying mechanisms for the Li + -induced dRTA are still unknown. To address this point, a 7 days time course of the urinary acid-base parameters was investigated in rats challenged with LiCl, LiCitrate, NaCl, or NaCitrate. LiCl induced the largest polyuria and a mild metabolic acidosis. Li + -treatment induced a biphasic response. In the first 2 days, proper urine volume and acidification occurred, while from the 3rd day of treatment, polyuria developed progressively. In this latter phase, the LiCl-treated group progressively excreted more NH 4 + and less pCO 2 , suggesting that NH 3 /NH 4 + became the main urinary buffer. This physiological parameter was corroborated by the upregulation of NBCn1 (a marker of increased ammonium recycling) in the inner stripe of outer medulla of LiCl treated rats. Finally, by investigating NH 4 + excretion in ENaC-cKO mice, a model resistant to Li + -induced polyuria, a primary role of the CD was confirmed. By definition, dRTA is characterized by deficient urinary ammonium excretion. Our data question the presence of a voltage-dependent Li + -induced dRTA in rats treated with LiCl for 7 days and the data suggest that the alkaline urine pH induced by NH 3 /NH 4 + as the main buffer has lead to the interpretation dRTA in previous studies.

  5. Effect of a supplement rich in alkaline minerals on acid-base balance in humans

    Directory of Open Access Journals (Sweden)

    König Daniel

    2009-06-01

    Full Text Available Abstract Background Western diets are considered acidogenic due to the high dietary acid load and a low intake of base-forming dietary minerals such as potassium, magnesium or calcium. In the present study we investigated the effect of a multimineral supplement (MMS rich in alkaline minerals on acute and chronic regulation of acid-base balance with the pH of blood, urine and saliva as potential surrogate markers. Methods Parameters were measured (i without MMS intake, (ii in the three consecutive hours following ingestion (blood and urinary pH and (iii during one week with or without MMS intake (self-monitored using pH measurement strips. Results 25 (15 female; 10 male subjects (age 44 ± 14 y; BMI 23.9 ± 1.9 kg/m2 were enrolled in the investigation. Following acute administration of the MMS in the morning, blood ph (1 and 2 h after ingestion rose from 7.40 to 7.41; p Following longer-term supplementation, both the increase in urinary pH in the morning and in the evening occurred within 1 day. Compared to pH values without the MMS, average pH in urine was 11% higher in the morning and 5% higher in the evening. Analyses of food records showed that the increase in urinary pH was not related to dietary change. Conclusion Our results suggest that the ingestion of a multimineral supplement is associated with both a significant increase in blood and urinary pH. The health related consequences of this supplementation remain to be determined.

  6. Amino acid-based surfactants – do they deserve more attention?

    Science.gov (United States)

    Bordes, Romain; Holmberg, Krister

    2015-08-01

    The 20 standard amino acids (together with a few more that are not used in the biosynthesis of proteins) constitute a versatile tool box for synthesis of surfactants. Anionic, cationic and zwitterionic amphiphiles can be prepared and surfactants with several functional groups can be obtained by the proper choice of starting amino acid. This review gives examples of procedures used for preparation and discusses important physicochemical properties of the amphiphiles and how these can be taken advantage of for various applications. Micelles with a chiral surface can be obtained by self-assembly of enantiomerically pure surfactants and such supramolecular chirality can be utilized for asymmetric organic synthesis and for preparation of mesoporous materials with chiral pores. Surfactants based on amino acids with two carboxyl groups are effective chelating agents and can be used as collectors in mineral ore flotation. A surfactant based on cysteine readily oxidizes into the corresponding cystine compound, which can be regarded as a gemini surfactant. The facile and reversible cysteine-cystine transformation has been taken advantage of in the design of a switchable surfactant. A very attractive aspect of surfactants based on amino acids is that the polar head-group is entirely natural and that the linkage to the hydrophobic tail, which is often an ester or an amide bond, is easily cleaved. The rate of degradation can be tailored by the structure of the amphiphile. The ester linkage in betaine ester surfactants is particularly susceptible to alkaline hydrolysis and this surfactant type can be used as a biocide with short-lived action. This paper is not intended as a full review on the topic. Instead it highlights concepts that are unique to amino acid-based surfactants and that we believe can have practical implications. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Salicylic Acid-Based Polymers for Guided Bone Regeneration Using Bone Morphogenetic Protein-2.

    Science.gov (United States)

    Subramanian, Sangeeta; Mitchell, Ashley; Yu, Weiling; Snyder, Sabrina; Uhrich, Kathryn; O'Connor, J Patrick

    2015-07-01

    Bone morphogenetic protein-2 (BMP-2) is used clinically to promote spinal fusion, treat complex tibia fractures, and to promote bone formation in craniomaxillofacial surgery. Excessive bone formation at sites where BMP-2 has been applied is an established complication and one that could be corrected by guided tissue regeneration methods. In this study, anti-inflammatory polymers containing salicylic acid [salicylic acid-based poly(anhydride-ester), SAPAE] were electrospun with polycaprolactone (PCL) to create thin flexible matrices for use as guided bone regeneration membranes. SAPAE polymers hydrolyze to release salicylic acid, which is a nonsteroidal anti-inflammatory drug. PCL was used to enhance the mechanical integrity of the matrices. Two different SAPAE-containing membranes were produced and compared: fast-degrading (FD-SAPAE) and slow-degrading (SD-SAPAE) membranes that release salicylic acid at a faster and slower rate, respectively. Rat femur defects were treated with BMP-2 and wrapped with FD-SAPAE, SD-SAPAE, or PCL membrane or were left unwrapped. The effects of different membranes on bone formation within and outside of the femur defects were measured by histomorphometry and microcomputed tomography. Bone formation within the defect was not affected by membrane wrapping at BMP-2 doses of 12 μg or more. In contrast, the FD-SAPAE membrane significantly reduced bone formation outside the defect compared with all other treatments. The rapid release of salicylic acid from the FD-SAPAE membrane suggests that localized salicylic acid treatment during the first few days of BMP-2 treatment can limit ectopic bone formation. The data support development of SAPAE polymer membranes for guided bone regeneration applications as well as barriers to excessive bone formation.

  8. Neonatal Acid-Base Status in Fetuses with Abnormal Vertebro- and Cerebro-Placental Ratios.

    Science.gov (United States)

    Morales-Roselló, José; Khalil, Asma; Ferri-Folch, Blanca; Perales-Marín, Alfredo

    2015-01-01

    A low cerebro-placental ratio (CPR) at term suggests the existence of failure to reach growth potential (FRGP) with a higher risk of poor neonatal acid-base status. This study aimed to evaluate whether similar findings were also seen in the vertebral artery (vertebro-placental ratio, VPR), supplying 30% of the cerebral flow. We studied term fetuses classified into groups according to birth weight (BW), CPR and VPR. BW was expressed in centiles and ratios in multiples of the median (MoM). Subsequently, associations with neonatal pH values were evaluated by means of regression curves and Mann-Whitney tests. VPR MoM correlated with BW centiles (p < 0.0001, R2 = 0.042) and its distribution resembled that of CPR MoM (p < 0.001). When both arteries were compared, adequate-for-gestational-age (AGA) fetuses with either low CPR or low VPR had lower neonatal venous pH values (p < 0.05, p < 0.01, respectively). However, in case of small-for-gestational-age (SGA) fetuses, only those with low VPR had significantly lower neonatal arterial and venous pH values (p < 0.05). Blood flow in the vertebral artery mimics that in the middle cerebral artery supporting the FRGP model. Both CPR and VPR identify AGA fetuses with lower neonatal pH values, but only VPR identifies SGA with lower pH values. Hypoxemia might be reflected as a generalized cerebral vasodilation demonstrated as low CPR and VPR.

  9. The possibility of determining the activity coefficients of individual ions from acid-base titration data

    Science.gov (United States)

    Jano, I.; Hardcastle, J. E.

    1998-07-01

    A method is described for obtaining the activity coefficients of individual ions from experimental titration data. For this purpose, a general polyprotic acid-base-titration-curve equation is derived. The equation allows obtaining the dissociation equilibrium constants of the acid and the ratio of the activity coefficient of each ion to the activity coefficient of the undissociated acid directly from the titration data. Results obtained are compared with coefficients calculated using Debye-Hückel equation. A general equation relating the ionic strength to the pH of the titration medium is also established. Une méthode pour l'obtention des coefficients d'activité des ions individuels à partir des données expérimentales de titrage est établie. À ce but, une équation générale est dérivée pour représenter la courbe de titrage d'un acide avec une base. Cette équation permet d'obtenir les constants d'équilibre de dissociation de l'acide et le rapport de coefficient d'activité de chaque ion au coefficient d'activité de l'acide non-dissocié à partir des données de titrage. Les résultats ainsi obtenus sont comparés avec les coefficients calculés à l'aide de l'équation de Debye-Hückel. Une équation liant la force ionique au pH du milieu est établie aussi.

  10. Acid-base analysis of individuals following two weight loss diets.

    Science.gov (United States)

    Yancy, W S; Olsen, M K; Dudley, T; Westman, E C

    2007-12-01

    To examine the effects of low-carbohydrate, ketogenic (LCKD) and low-fat (LFD) diets on acid-base status. Prospective analysis of volunteers from two clinical trials. Subset of 39 volunteers from a randomized trial comparing the effects of an LCKD with an LFD, and a single-arm trial of an LCKD. Outpatient research clinic. LCKD (initially ketone bodies, lactate), anion gap, and urine ketone bodies measured at weeks 0, 2, 8, and 24. Participants had a mean (+/-standard deviation) age of 43.5+/-9.3 years; 28 (72%) were female, 29 (74%) were Caucasian. Using linear mixed-model analysis to examine blood test changes from baseline to 24 weeks, the LFD group experienced a decrease in arterial blood pH from a mean of 7.43 at week 0 to 7.40 at week 24 (P=0.03), and the LCKD group experienced a decrease from 7.42 at week 0 to 7.40 at week 24 (P=0.01). The lowest pH measurements observed were 7.34 in the LFD group and 7.37 in the LCKD group. Although serum bicarbonate appeared to decrease from baseline at weeks 2 and 8 in the LCKD group, the change at 24 weeks was not statistically significant in either diet group, and only four of 131 (two of 92 from the LCKD group) measurements were less than 22 mmol/l. The proportion of participants with elevated urine and serum ketone body levels rose in the LCKD group only, was highest at week 2, and decreased over the subsequent time points. In individuals following an LCKD or an LFD, blood pH decreased mildly and the LCKD group experienced a small, transient decrease in serum bicarbonate in conjunction with mild ketosis. This suggests that an LCKD induced a mild compensated metabolic acidosis, but no individual showed evidence of significant metabolic derangement.

  11. Methylene-bis[(aminomethyl)phosphinic acids]: synthesis, acid-base and coordination properties.

    Science.gov (United States)

    David, Tomáš; Procházková, Soňa; Havlíčková, Jana; Kotek, Jan; Kubíček, Vojtěch; Hermann, Petr; Lukeš, Ivan

    2013-02-21

    Three symmetrical methylene-bis[(aminomethyl)phosphinic acids] bearing different substituents on the central carbon atom, (NH(2)CH(2))PO(2)H-C(R(1))(R(2))-PO(2)H(CH(2)NH(2)) where R(1) = OH, R(2) = Me (H(2)L(1)), R(1) = OH, R(2) = Ph (H(2)L(2)) and R(1),R(2) = H (H(2)L(3)), were synthesized. Acid-base and complexing properties of the ligands were studied in solution as well as in the solid state. The ligands show unusually high basicity of the nitrogen atoms (log K(1) = 9.5-10, log K(2) = 8.5-9) if compared with simple (aminomethyl)phosphinic acids and, consequently, high stability constants of the complexes with studied divalent metal ions. The study showed the important role of the hydroxo group attached to the central carbon atom of the geminal bis(phosphinate) moiety. Deprotonation of the hydroxo group yields the alcoholate anion which tends to play the role of a bridging ligand and induces formation of polynuclear complexes. Solid-state structures of complexes [H(2)N=C(NH(2))(2)][Cu(2)(H(-1)L(2))(2)]CO(3)·10H(2)O and Li(2)[Co(4)(H(-1)L(1))(3)(OH)]·17.5H(2)O were determined by X-ray diffraction. The complexes show unexpected geometries forming dinuclear and cubane-like structures, respectively. The dinuclear copper(II) complex contains a bridging μ(2)-alcoholate group with the (-)O-P(=O)-CH(2)-NH(2) fragments of each ligand molecule chelated to the different central ion. In the cubane cobalt(II) complex, one μ(3)-hydroxide and three μ(3)-alcoholate anions are located in the cube vertices and both phosphinate groups of one ligand molecule are chelating the same cobalt(II) ion while each of its amino groups are bound to different neighbouring metal ions. All such three metal ions are bridged by the alcoholate group of a given ligand.

  12. Potential of capillary zone electrophoresis for estimation of humate acid-base properties.

    Science.gov (United States)

    Vanifatova, Natalia G; Zavarzina, Anna G; Spivakov, Boris Ya

    2008-03-07

    Capillary zone electrophoresis (CZE) has been applied for fractionation and characterization of soil-derived humic acids (HAs). Humic acids from soddy-podzolic (HA(s)) and chernozem (HA(ch)) soils were studied as well as hydrophobic high-molecular-weight (HMW) and hydrophilic low-molecular-weight (LMW) HA(s) fractions obtained by salting-out with ammonium sulfate at a saturation of 0-40% and >70%, respectively. The possibility of CZE partial fractionation of HAs has been demonstrated. The shape of "humic hump" was shown to depend on the pH of running electrolyte. Almost the whole peak overlapping occurred if alkaline solutions were used for fractionation, but the peak resolution was improved at pH 5-7. Under appropriate fractionation conditions (pH 7), at least three humic acid subfractions with different electrophoretic mobilities were distinguished in the electropherograms of initial HA and HA(s) fractions. Such a high peak resolution has never been achieved for humic acids before. The presence of three subfractions in the HA is in agreement with gel-filtration analysis and was confirmed by comparison of the electrophoretic behavior of HA(s) with those of its HMW (hydrophobic) and the LMW (hydrophilic) fractions. The potentiometric titration of HA and its fractions was performed and the pK(a) of the functional groups were calculated. An attempt was made for the first time to relate the variation of electrophoretic mobility values with acid-base properties of humic acids. It was shown that changes in the humate charge resulting from the variation of the ionization degree of its functional groups as a function of pH can be estimated on the basis of electrophoretic mobility values. Potential of CZE in estimation of HA isoelectric point was demonstrated. The pH value corresponding to the lowest absolute electrophoretic mobility value of about 20 x 10(-5) cm(2) V(-1) s(-1) can be used for approximate estimation of HA isoelectric point. The data were discussed and

  13. Spherical Nucleic Acids as Intracellular Agents for Nucleic Acid Based Therapeutics

    Science.gov (United States)

    Hao, Liangliang

    Recent functional discoveries on the noncoding sequences of human genome and transcriptome could lead to revolutionary treatment modalities because the noncoding RNAs (ncRNAs) can be applied as therapeutic agents to manipulate disease-causing genes. To date few nucleic acid-based therapeutics have been translated into the clinic due to challenges in the delivery of the oligonucleotide agents in an effective, cell specific, and non-toxic fashion. Unmodified oligonucleotide agents are destroyed rapidly in biological fluids by enzymatic degradation and have difficulty crossing the plasma membrane without the aid of transfection reagents, which often cause inflammatory, cytotoxic, or immunogenic side effects. Spherical nucleic acids (SNAs), nanoparticles consisting of densely organized and highly oriented oligonucleotides, pose one possible solution to circumventing these problems in both the antisense and RNA interference (RNAi) pathways. The unique three dimensional architecture of SNAs protects the bioactive oligonucleotides from unspecific degradation during delivery and supports their targeting of class A scavenger receptors and endocytosis via a lipid-raft-dependent, caveolae-mediated pathway. Owing to their unique structure, SNAs are able to cross cell membranes and regulate target genes expression as a single entity, without triggering the cellular innate immune response. Herein, my thesis has focused on understanding the interactions between SNAs and cellular components and developing SNA-based nanostructures to improve therapeutic capabilities. Specifically, I developed a novel SNA-based, nanoscale agent for delivery of therapeutic oligonucleotides to manipulate microRNAs (miRNAs), the endogenous post-transcriptional gene regulators. I investigated the role of SNAs involving miRNAs in anti-cancer or anti-inflammation responses in cells and in in vivo murine disease models via systemic injection. Furthermore, I explored using different strategies to construct

  14. Does acid-base equilibrium correlate with remnant liver volume during stepwise liver resection?

    Science.gov (United States)

    Golriz, Mohammad; Abbasi, Sepehr; Fathi, Parham; Majlesara, Ali; Brenner, Thorsten; Mehrabi, Arianeb

    2017-10-01

    Small for size and flow syndrome (SFSF) is one of the most challenging complications following extended hepatectomy (EH). After EH, hepatic artery flow decreases and portal vein flow increases per 100 g of remnant liver volume (RLV). This causes hypoxia followed by metabolic acidosis. A correlation between acidosis and posthepatectomy liver failure has been postulated but not studied systematically in a large animal model or clinical setting. In our study, we performed stepwise liver resections on nine pigs to defined SFSF limits as follows: step 1: segment II/III resection, step 2: segment IV resection, step 3: segment V/VIII resection (RLV: 75, 50, and 25%, respectively). Blood gas values were measured before and after each step using four catheters inserted into the carotid artery, internal jugular vein, hepatic artery, and portal vein. The pH, [Formula: see text], and base excess (BE) decreased, but [Formula: see text] values increased after 75% resection in the portal and jugular veins. EH correlated with reduced BE in the hepatic artery. Pco 2 values increased after 75% resection in the jugular vein. In contrast, arterial Po 2 increased after every resection, whereas the venous Po 2 decreased slightly. There were differences in venous [Formula: see text], BE in the hepatic artery, and Pco 2 in the jugular vein after 75% liver resection. Because 75% resection is the limit for SFSF, these noninvasive blood evaluations may be used to predict SFSF. Further studies with long-term follow-up are required to validate this correlation. NEW & NOTEWORTHY This is the first study to evaluate acid-base parameters in major central and hepatic vessels during stepwise liver resection. The pH, [Formula: see text], and base excess (BE) decreased, but [Formula: see text] values increased after 75% resection in the portal and jugular veins. Extended hepatectomy correlated with reduced BE in the hepatic artery. Because 75% resection is the limit for small for size and flow

  15. Red blood transfusion in preterm infants: changes in glucose, electrolytes and acid base balance

    Directory of Open Access Journals (Sweden)

    Shereen Abdelghaffar

    2012-01-01

    Full Text Available Background: Preterm neonates comprise the most heavily transfused group of patients, and about 85% of extremely low birth weight newborns receive a transfusion by the end of their hospital stay. The aim of this study was to assess the possible metabolic effects of RBC transfusion on preterm infants, especially during the first 2 weeks of life, and its relation to blood volume. Materials and Methods: This study was conducted on 40 preterm neonates with gestational age of less than or equal to 34 weeks. They received RBCs transfusion during first 2 weeks of life. Venous blood samples of infants were collected 2 to 4 hours before and 1 hour after the end of transfusion to evaluate hemoglobin (Hb level, hematocrit, acid-base, electrolytes, and glucose status. Then, infants were classified into two main groups: those who received RBCs volume less than or 20 ml/kg and those who received RBCs volume more than 20 ml/kg. Results: Infants received a mean volume of 20.38 ± 3.2 ml/kg RBCs (range, 10.9 - 26.6 ml/kg at a median age of 9.8 ± 3.6 days. After transfusion, a significant increase of mean Hb (P<0.001, mean Hct (P<0.001, pH (P<0.001, pO 2 (P<0.05, and a significant decrease of the pCO2 (41.46 ± 8.8torr vs 35.4 ± 9.34 torr; P<0.001 were observed. In addition, there was a significant increase of serum K + (P<0.001, and a significant decrease of Ca +2 (P<0.001. A positive correlation was found between the K + intake and the changes of kalemia (r = 0.99; P = 0.00. Furthermore, we observed an inverse correlation between the patients′ calcium intake and the changes of calcemia (r = -0.35; P = 0.02. On comparing the changes in clinical and biochemical variables between two groups after transfusion, we observed a significant increase in mean Hb and Hct associated with a significant decrease in mean serum Ca +2 (P<0.001 in the group receiving the larger blood volume. Conclusion: RBC transfusion was effective in improving anemia, oxygenation, increasing

  16. The acid-base effects of continuous hemofiltration with lactate or bicarbonate buffered replacement fluids.

    Science.gov (United States)

    Tan, H K; Uchino, S; Bellomo, R

    2003-06-01

    To evaluate, quantify and compare the effects of continuous veno-venous hemofiltration (CVVH) with lactate or bicarbonate-buffered replacement fluids on acid-base balance. Randomized double crossover study. Intensive Care Unit of Tertiary Medical Center. Eight patients with severe acute renal failure. Random allocation to either 2 hours of isovolemic lactate-buffered (treatment A) CVVH or 2 hours of bicarbonate-buffered (treatment B) CVVH with cross over and with same procedure repeated the following day (double cross over). Timed collections of arterial blood and ultrafiltrate (UF), measurement of blood and UF gases and lactate concentrations and calculation of buffer-base mass balance. At baseline, both groups of patients had a similar, slight metabolic alkalosis (pH: 7.45 vs. 7.45; BE 3.9 mEq/L for treatment A and 4.0 for treatment B) and a serum bicarbonate of 28.1 mmol/L for treatment A vs. 28.3 mmol/L for treatment B; all NS. This alkalosis was present despite slight hyperlactatemia in both groups (A: 2.4 mmol/L vs. B 2.8 mmol/; NS). Within 60 minutes of treatment, however, treatment A led to a significantly higher lactate concentration (3.9 vs 2.5 mmol/L; p = 0.0011), a significantly lower BE (2.3 vs 4.1 mEq/L; p = 0.0019) and a significantly lower bicarbonate concentration (26.7 vs. 28.3 mmol/L; p = 0.0038) in the presence of an unchanged PaCO2. These differences persisted during the study period. The UF of patients receiving treatment A contained more lactate (10.2 vs 2.9 mmol/L; p buffer-base balance of +20.4 mEq/h compared to -2.6 mEq/h for treatment B; p buffered replacement fluids induces iatrogenic hyperlactatemia. Such hyperlactatemia is associated with an acidifying effect despite a positive buffer-base balance.

  17. Acid base activity of live bacteria: Implications for quantifying cell wall charge

    Science.gov (United States)

    Claessens, Jacqueline; van Lith, Yvonne; Laverman, Anniet M.; Van Cappellen, Philippe

    2006-01-01

    To distinguish the buffering capacity associated with functional groups in the cell wall from that resulting from metabolic processes, base or acid consumption by live and dead cells of the Gram-negative bacterium Shewanella putrefaciens was measured in a pH stat system. Live cells exhibited fast consumption of acid (pH 4) or base (pH 7, 8, 9, and 10) during the first few minutes of the experiments. At pH 5.5, no acid or base was required to maintain the initial pH constant. The initial amounts of acid or base consumed by the live cells at pH 4, 8, and 10 were of comparable magnitudes as those neutralized at the same pHs by intact cells killed by exposure to gamma radiation or ethanol. Cells disrupted in a French press required higher amounts of acid or base, due to additional buffering by intracellular constituents. At pH 4, acid neutralization by suspensions of live cells stopped after 50 min, because of loss of viability. In contrast, under neutral and alkaline conditions, base consumption continued for the entire duration of the experiments (5 h). This long-term base neutralization was, at least partly, due to active respiration by the cells, as indicated by the build-up of succinate in solution. Qualitatively, the acid-base activity of live cells of the Gram-positive bacterium Bacillus subtilis resembled that of S. putrefaciens. The pH-dependent charging of ionizable functional groups in the cell walls of the live bacteria was estimated from the initial amounts of acid or base consumed in the pH stat experiments. From pH 4 to 10, the cell wall charge increased from near-zero values to about -4 × 10 -16 mol cell -1 and -6.5 × 10 -16 mol cell -1 for S. putrefaciens and B. subtilis, respectively. The similar cell wall charging of the two bacterial strains is consistent with the inferred low contribution of lipopolysaccharides to the buffering capacity of the Gram-negative cell wall (of the order of 10%).

  18. Oxalate Acid-Base Cements as a Means of Carbon Storage

    Science.gov (United States)

    Erdogan, S. T.

    2017-12-01

    Emission of CO2 from industrial processes poses a myriad of environmental problems. One such polluter is the portland cement (PC) industry. PC is the main ingredient in concrete which is the ubiquitous binding material for construction works. Its production is responsible for 5-10 % of all anthropogenic CO2 emissions. Half of this emission arises from the calcination of calcareous raw materials and half from kiln fuel burning and cement clinker grinding. There have long been efforts to reduce the carbon footprint of concrete. Among the many ways, one is to bind CO2 to the phases in the cement-water paste, oxides, hydroxides, and silicates of calcium, during early hydration or while in service. The problem is that obtaining calcium oxide cheaply requires the decarbonation of limestone and the uptake of CO2 is slow and limited mainly to the surface of the concrete due to its low gas permeability. Hence, a faster method to bind more CO2 is needed. Acid-base (AB) cements are fast-setting, high-strength systems that have high durability in many environments in which PC concrete is vulnerable. They are made with a powder base such as MgO and an acid or acid salt, like phosphates. Despite certain advantages over PC cement systems, AB cements are not feasible, due to their high acid content. Also, the phosphoric acid used comes from non-renewable sources of phosphate. A potential way to reduce the drawbacks of using phosphates could be to use organic acids. Oxalic acid or its salts could react with the proper powder base to give concrete that could be used for infrastructure hence that would have very high demand. In addition, methods to produce oxalates from CO2, even atmospheric, are becoming widespread and more economical. The base can also be an industrial byproduct to further lower the environmental impact. This study describes the use of oxalic acid and industrial byproducts to obtain mortars with mechanical properties comparable to those of PC mortars. It is

  19. Metabolic fate of poly-(lactic-co-glycolic acid-based curcumin nanoparticles following oral administration

    Directory of Open Access Journals (Sweden)

    Harigae T

    2016-06-01

    Full Text Available Takahiro Harigae,1 Kiyotaka Nakagawa,1 Taiki Miyazawa,2 Nao Inoue,3 Fumiko Kimura,1 Ikuo Ikeda,3 Teruo Miyazawa4,5 1Food and Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan; 2Vascular Biology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA; 3Laboratory of Food and Biomolecular Science, Graduate School of Agricultural Science, 4Food and Biotechnology Innovation Project, New Industry Creation Hatchery Center, 5Food and Health Science Research Unit, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan Purpose: Curcumin (CUR, the main polyphenol in turmeric, is poorly absorbed and rapidly metabolized following oral administration, which severely curtails its bioavailability. Poly-(lactic-co-glycolic acid-based CUR nanoparticles (CUR-NP have recently been suggested to improve CUR bioavailability, but this has not been fully verified. Specifically, no data are available about curcumin glucuronide (CURG, the major metabolite of CUR found in the plasma following oral administration of CUR-NP. Herein, we investigated the absorption and metabolism of CUR-NP and evaluated whether CUR-NP improves CUR bioavailability.Methods: Following oral administration of CUR-NP in rats, we analyzed the plasma and organ distribution of CUR and its metabolites using high-performance liquid chromatography-tandem mass spectrometry. To elucidate the mechanism of increased intestinal absorption of CUR-NP, we prepared mixed micelles comprised of phosphatidylcholine and bile salts and examined the micellar solubility of CUR-NP. Additionally, we investigated the cellular incorporation of the resultant micelles into differentiated Caco-2 human intestinal cells.Results: Following in vivo administration of CUR-NP, CUR was effectively absorbed and present mainly as CURG in the plasma which contained significant amounts of the metabolite compared with

  20. Study in the behavior of several heavy elements in solvents with hydrofluoric acid base

    International Nuclear Information System (INIS)

    Tarnero, M.

    1988-01-01

    Initial goal was the study of two nonaqueous solvents with an HF base, one with an oxidizing character, N 2 O 4 -HF, the other with an acid character, SbF 5 -HF. For the N 2 O 4 -HF mixtures, nitric acid and NO 2 + ions exist in these media, nitric acid is dissociated for concentrations of N 2 O 4 2 + ions. Results for the dissolution of metals agree with those of Brookhaven. For uranium, the speed did not increase in clear fashion from 60-70/degree/C, but that it obeyed Arrhenius' law between 40 and 115/degree/C. UF 4 was more soluble than ZrF 4 . U(IV) passed to U(V) after dissolution. The compound obtained from UF 4 was the same as that obtained from the metal uranium, i.e., NOUF 6 . U(VI)appeared to be poorly soluble, the uranium passes into solution particularly at valence 5. For SbF 5 -HF mixtures, the corrosion speeds were much lower than in N 2 O 4 -HF mixtures. For Zr, rates of dissolution are very low, while they are very high with N 2 O 4 -HF. Th is practically not corroded at all. Al was not corroded at all up to 90/degree/C. Only U was dissolved at higher rates than Th and Zr; however, the corrosion speeds at 90/degree/C are equal to those with the N 2 O 4 -HF mixtures at 50/degree/C. This shows that U passed into solution in the trivalent state, and that the product was U(SbF 6 ) 3 . The trivalent uranium compounds were more soluble than the others. Addition of N 2 O 4 to SbF 5 -HF induces acid-base reactions between the NO + and NO 2 /sup /minus// on the one hand, and SbF 6 /sup /minus// on the other hand, reactions accompanying the formation of a precipitate, probably a NOSbF 6 and NO 2 SbF 6 mixture. 66 refs., 34 figs., 23 tabs

  1. Different effects of fluid loading with saline, gelatine, hydroxyethyl starch or albumin solutions on acid-base status in the critically ill

    NARCIS (Netherlands)

    A.M.E. Spoelstra-de Ma (Angélique M. E.); A. Smorenberg (Annemieke); A.B.J. Groeneveld (Johan)

    2017-01-01

    textabstractIntroduction Fluid administration in critically ill patients may affect acid-base balance. However, the effect of the fluid type used for resuscitation on acid-base balance remains controversial. Methods We studied the effect of fluid resuscitation of normal saline and the colloids

  2. The Acid-Base Properties and Chemical Composition of the Surface of the InSb-ZnTe System

    Science.gov (United States)

    Kirovskaya, I. A.; Shubenkova, E. G.; Timoshenko, O. T.; Filatova, T. N.

    2008-04-01

    The acid-base properties and chemical composition of the surface of solid solutions and binary components of the InSb-ZnTe system were studied by the hydrolytic adsorption, nonaqueous conductometric titration, mechanochemistry, IR spectroscopy, and mass spectrometry methods. The strength, nature, and concentration of acid centers were determined. Changes in the concentration of acid centers caused by surface exposure to CO and changes in the composition of the system were also studied. The mechanism of acid-base interactions was established. The chemical composition of the surface of system components exposed to air included adsorbed H2O molecules, OH- groups, hydrocarbon and oxocarbon compounds, and the products of surface atom oxidation. After thermal treatment in a vacuum, the composition of the surface approached the stoichiometric composition.

  3. Relationships among oxidation-reduction and acid-base properties of the actinides in high oxidation states

    International Nuclear Information System (INIS)

    Morss, L.R.

    1992-01-01

    The first chemical identification of plutonium, its subsequent isolation on the macroscopic scale, and more recent chemical separation schemes were achieved by taking advantage of the differences among the oxidation states of uranium, neptunium, and plutonium. Many acid-base properties modify the relative stabilities of oxidation states of the actinides. In the solid state, strongly basic compounds such as Cs 2 O yield complex oxides with oxidation states of Np(VII), Pu(VI), and Am(VI) whereas more acidic compounds such as CsF yield complex fluorides with lower oxidation states. In aqueous solution, high basicity and strongly covalent complexes favor high oxidation states. In nonaqueous solvent systems, high acidity generally favors low oxidation states. This paper elucidates and attempts to interpret the effects of these acid-base properties in a systematic fashion

  4. Mixed acid-base disorders, hydroelectrolyte imbalance and lactate production in hypercapnic respiratory failure: the role of noninvasive ventilation.

    Directory of Open Access Journals (Sweden)

    Claudio Terzano

    Full Text Available BACKGROUND: Hypercapnic Chronic Obstructive Pulmonary Disease (COPD exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV when treating hypercapnic respiratory failure. METHODS: Sixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed. Heart and respiratory rates, pH, PaO(2 and PaCO(2 and blood lactate were checked at the 1st, 2nd, 6th and 24th hours after starting NIV. RESULTS: Nine patients were transferred to the intensive care unit. NIV was performed in 11/17 (64.7% mixed respiratory acidosis-metabolic alkalosis, 10/36 (27.8% respiratory acidosis and 3/5 (60% mixed respiratory-metabolic acidosis patients (p = 0.026, with durations of 45.1 ± 9.8, 36.2 ± 8.9 and 53.3 ± 4.1 hours, respectively (p = 0.016. The duration of ventilation was associated with higher blood lactate (p<0.001, lower pH (p = 0.016, lower serum sodium (p = 0.014 and lower chloride (p = 0.038. Hyponatremia without hypervolemic hypochloremia occurred in 11 respiratory acidosis patients. Hypovolemic hyponatremia with hypochloremia and hypokalemia occurred in 10 mixed respiratory acidosis-metabolic alkalosis patients, and euvolemic hypochloremia occurred in the other 7 patients with this mixed acid-base disorder. CONCLUSIONS: Mixed acid-base and lactate disorders during hypercapnic COPD exacerbations predict the need for and longer duration of NIV. The combination of mixed acid-base disorders and hydro-electrolyte disturbances should be further investigated.

  5. Mixed Acid-Base Disorders, Hydroelectrolyte Imbalance and Lactate Production in Hypercapnic Respiratory Failure: The Role of Noninvasive Ventilation

    Science.gov (United States)

    Terzano, Claudio; Di Stefano, Fabio; Conti, Vittoria; Di Nicola, Marta; Paone, Gregorino; Petroianni, Angelo; Ricci, Alberto

    2012-01-01

    Background Hypercapnic Chronic Obstructive Pulmonary Disease (COPD) exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV) when treating hypercapnic respiratory failure. Methods Sixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed. Heart and respiratory rates, pH, PaO2 and PaCO2 and blood lactate were checked at the 1st, 2nd, 6th and 24th hours after starting NIV. Results Nine patients were transferred to the intensive care unit. NIV was performed in 11/17 (64.7%) mixed respiratory acidosis–metabolic alkalosis, 10/36 (27.8%) respiratory acidosis and 3/5 (60%) mixed respiratory-metabolic acidosis patients (p = 0.026), with durations of 45.1±9.8, 36.2±8.9 and 53.3±4.1 hours, respectively (p = 0.016). The duration of ventilation was associated with higher blood lactate (pmetabolic alkalosis patients, and euvolemic hypochloremia occurred in the other 7 patients with this mixed acid-base disorder. Conclusions Mixed acid-base and lactate disorders during hypercapnic COPD exacerbations predict the need for and longer duration of NIV. The combination of mixed acid-base disorders and hydro-electrolyte disturbances should be further investigated. PMID:22539963

  6. Monitoring of acid-base status of workers at a methyl methacrylate and polymethyl methacrylate production plant in Bulgaria.

    Science.gov (United States)

    Prakova, Gospodinka R

    2003-01-01

    This study was carried out on 104 workers at three work operations and a control (nonproduction) area, within a methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) production facility in Bulgaria. Airborne monitoring was conducted over a 10-year period for MMA and the reactant chemicals methanol and acetone cyanhydrine at the MMA operation, and MMA was monitored at the PMMA operation. Acid-base status of the workers was evaluated using traditional criteria (pH, pCO(2), pO(2), and HCO(3) in plasma). Data from retrospective monitoring of air levels of the chemicals were compared with the acid-base status of workers at the plant. In some cases air concentrations exceeded the threshold limit value, with the highest percentage of overexposure occurring with airborne MMA in the PMMA production operation. Acid-base disruption indicated by reductions in plasma pH and HCO(3) was found for all groups except the control population. The highest percentage reduction was associated with PMMA production workers. Additionally, respiratory acidosis, indicated by increased pCO(2), was noted in the MMA production and maintenance groups, implying that the response to MMA exposure may involve both the metabolic and respiratory acidosis component. This study was unique in that the combined exposure to MMA and the precursor chemical (methanol) were shown to produce the same effects in workers. It is suggested that when combined exposure occurs, disruption of acid-base status may occur. Enforcement of PPM requirements for coveralls and gloves should prevent skin contamination. Additionally, improvement of equipment in MMA and PMMA production areas is recommended: (1) automation of some manual operations; (2) use of respiratory protection during equipment cleaning; and (3) installation of local ventilation when applicable.

  7. Bench-to-bedside review: treating acid-base abnormalities in the intensive care unit - the role of buffers.

    Science.gov (United States)

    Gehlbach, Brian K; Schmidt, Gregory A

    2004-08-01

    The recognition and management of acid-base disorders is a commonplace activity for intensivists. Despite the frequency with which non-bicarbonate-losing forms of metabolic acidosis such as lactic acidosis occurs in critically ill patients, treatment is controversial. This article describes the properties of several buffering agents and reviews the evidence for their clinical efficacy. The evidence supporting and refuting attempts to correct arterial pH through the administration of currently available buffers is presented.

  8. Fast Hydrazone Reactants: Electronic and Acid/Base Effects Strongly Influence Rate at Biological pH

    OpenAIRE

    Kool, Eric T.; Park, Do-Hyoung; Crisalli, Pete

    2013-01-01

    Kinetics studies with structurally varied aldehydes and ketones in aqueous buffer at pH 7.4 reveal that carbonyl compounds with neighboring acid/base groups form hydrazones at accelerated rates. Similarly, tests of a hydrazine with a neighboring carboxylic acid group show that it also reacts at an accelerated rate. Rate constants for the fastest carbonyl/hydrazine combinations are 2–20 M−1sec−1, which is faster than recent strain-promoted cycloaddition reactions.

  9. Recent developments in nucleic acid based techniques for use in rumen manipulation

    Directory of Open Access Journals (Sweden)

    Christopher McSweeney

    2009-07-01

    Full Text Available Nucleic acid-based techniques which can be used to characterise complex microbial communities without incubation are now being employed regularly in ruminant nutrition studies. Conventional culture-based methods for enumerating rumen microorganisms (bacteria, archaea, protozoa, and fungi have been superseded and are now used mainly to obtain pure isolates of novel organisms and reference strains that are required for the development and validation of the nucleic acid approaches. These reference strains are also essential for physiological studies of the lifestyle of the organisms as well as sources of genomic DNA and RNA that can be analysed for functional gene activity. The foundation of the molecular ecology techniques is 16S/18S rDNA sequence analysis which has provided a phylogenetically based classification scheme for enumeration and identification of microbial community members. The use of this marker gene in assays involving the use of single nucleic acid probes or primer sets is rapidly evolving to high throughput approaches such as microarray analysis and new generation sequencing technologies. While these analyses are very informative for determining the composition of the microbial community and monitoring changes in population size, they can only infer function based on these observations. The focus of nucleic acid research is now shifting to the functional analysis of the ecosystem which involves the measurement of functional genes and their expression in the predominant or specific members of the rumen microbial community. Functional gene studies are less developed than 16S rDNA-based analysis of community structure. Also for gene expression studies there are inherent problems involved in extracting high quality RNA from digesta, and priming cDNA synthesis from bacterial mRNA. This paper reviews nucleic acid based molecular methods which have recently been developed for studying the structure and function of rumen microbial

  10. Influence of Catalyst Acid/Base Properties in Acrolein Production by Oxidative Coupling of Ethanol and Methanol.

    Science.gov (United States)

    Lilić, Aleksandra; Bennici, Simona; Devaux, Jean-François; Dubois, Jean-Luc; Auroux, Aline

    2017-05-09

    Oxidative coupling of methanol and ethanol represents a new route to produce acrolein. In this work, the overall reaction was decoupled in two steps, the oxidation and the aldolization, by using two consecutive reactors to investigate the role of the acid/base properties of silica-supported oxide catalysts. The oxidation of a mixture of methanol and ethanol to formaldehyde and acetaldehyde was performed over a FeMoO x catalyst, and then the product mixture was transferred without intermediate separation to a second reactor, in which the aldol condensation and dehydration to acrolein were performed over the supported oxides. The impact of the acid/base properties on the selectivity towards acrolein was investigated under oxidizing conditions for the first time. The acid/base properties of the catalysts were investigated by NH 3 -, SO 2 -, and methanol-adsorption microcalorimetry. A MgO/SiO 2 catalyst was the most active in acrolein production owing to an appropriate ratio of basic to acidic sites. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The assessment of acid-base analysis: comparison of the “traditional” and the “modern” approaches

    Directory of Open Access Journals (Sweden)

    Jasna Todorović

    2015-02-01

    Full Text Available Three distinct approaches are currently used in assessing acid-base disorders: the traditional - physiological or bicarbonate-centered approach, the base-excess approach, and the “modern” physicochemical approach proposed by Peter Stewart, which uses the strong ion difference (particularly the sodium chloride difference and the concentration of nonvolatile weak acids (particularly albumin and partial pressure of carbon dioxide (pCO2 as independent variables in the assessment of acid-base status. The traditional approach developed from the pioneering work of Henderson and Hasselbalch and the base-excess are still most widely used in clinical practice, even though there are a number of problems identified with this approach. The approach works well clinically and is recommended for use whenever serum total protein, albumin and phosphate concentrations are normal. Although Stewart’s approach has been largely ignored by physiologists, it is increasingly used by anesthesiologists and intensive care specialists, and is recommended for use whenever serum’s total protein, albumin or phosphate concentrations are markedly abnormal, as in critically ill patients. Although different in their concepts, the traditional and modern approaches can be seen as complementary, giving in principle, the same information about the acid-base status.

  12. Acid-Base and Plasma Biochemical Changes Using Crystalloid Fluids in Stranded Juvenile Loggerhead Sea Turtles (Caretta caretta)

    Science.gov (United States)

    Camacho, María; Quintana, María del Pino; Calabuig, Pascual; Luzardo, Octavio P.; Boada, Luis D.; Zumbado, Manuel; Orós, Jorge

    2015-01-01

    Aim The aim of this study was to compare the efficacy and effects on acid-base and electrolyte status of several crystalloid fluids in 57 stranded juvenile loggerhead turtles. Methods Within a rehabilitation program four different crystalloid fluids were administered (0.9% Na Cl solution; 5% dextrose + 0.9% Na Cl solutions 1:1; 0.9% Na Cl + lactated Ringer's solutions 1:1; lactated Ringer's solution). Crystalloid fluids were intracoelomically administered during three days (20 ml/kg/day). Animals were sampled at three different moments: Upon admission for evaluating the type of acid-base or biochemical disorder, post-fluid therapy treatment for controlling the evolution of the disorder, and post-recovery period for obtaining the baseline values for rehabilitated loggerhead turtles. Each sample was analyzed with a portable electronic blood analyzer for pH, pO2, pCO2, lactate, sodium, potassium, chloride, glucose, and BUN concentration. Admission and post-fluid therapy treatment values were compared with those obtained for each turtle immediately before release. Results The highest percentage of acid-base recovery and electrolyte balance was observed in turtles treated with mixed saline-lactated Ringer’s solution (63.6%), followed by turtles treated with physiological saline solution (55%), lactated Ringer’s solution (33.3%), and dextrose-saline solutions (10%). Most turtles treated with lactated Ringer’s solution had lower lactate concentrations compared with their initial values; however, 66.6% of turtles treated with lactated Ringer’s solution had metabolic alkalosis after therapy. Significant higher concentrations of glucose were detected after saline-dextrose administration compared with all the remaining fluids. Conclusions This is the first study evaluating the effects of several crystalloid fluids on the acid-base status and plasma biochemical values in stranded loggerhead sea turtles. Reference convalescent venous blood gas, acid-base, and plasma

  13. Aspectos morfológicos, germinação e desenvolvimento inicial de plântulas de Archontophoenix alexandrae (F. Mueller H. Wendl. e Drude (Arecaceae em diferentes substratos Morphological aspects, germination and initial seedling development of Archontophoenix alexandrae (F. Mueller H. Wendl. e Drude (Arecaceae in different substrates

    Directory of Open Access Journals (Sweden)

    Hamilton César de Oliveira Charlo

    2006-12-01

    Full Text Available Este trabalho teve por objetivo descrever a morfologia dos diásporos e as suas fases de germinação, bem como determinar o substrato mais adequado para a germinação das sementes e o crescimento das plântulas de palmeira-da-rainha (Archontophoenix alexandrae (F. Mueller H. Wendl. e Drude. Periodicamente, unidades representativas de cada fase de germinação foram retiradas para as descrições morfológicas. Os substratos utilizados foram Plantmax®, areia, terra (latossolo roxo e outro com proporções iguais de terra, areia e esterco (TAE. Foi instalado um experimento em delineamento inteiramente casualizado. Avaliaram-se a porcentagem, o tempo médio de germinação e o crescimento inicial das plântulas aos 135 dias após a emergência, com base na altura, diâmetro do colo e número, comprimento e largura das folhas. As sementes são albuminosas, com endosperma ruminado e oleaginoso, e o embrião é lateral, periférico e relativamente indiferenciado. A germinação é do tipo criptocotiledonar hipógea, iniciando-se com a formação de uma massa de células indiferenciadas na depressão micropilar. Essa massa de células torna-se cilíndrica, com a diferenciação dos primórdios caulinares e radiculares. Concomitantemente, ocorre o desenvolvimento de raízes adventícias no eixo embrionário. O substrato mais indicado para a germinação de sementes de palmeira-da-rainha é o Plantmax®, porém, para o crescimento inicial, indica-se Plantmax® e TAE.This work aimed at describing the morphology and germination phases of diaspores, in order to determine a more suitable substrate for germination and growth of Queen Palm seedlings. Representative units of each germination phase were removed periodically for the morphological descriptions. The used substrates were Plantmax®, sand, rich soil and a substrate with equal ratios of soil, sand and manure (TAE. The experiment was performed in a completely randomized design. The percentage and

  14. Old and new approaches to the interpretation of acid-base metabolism, starting from historical data applied to diabetic acidosis.

    Science.gov (United States)

    Mioni, Roberto; Marega, Alessandra; Lo Cicero, Marco; Montanaro, Domenico

    2016-11-01

    The approach to acid-base chemistry in medicine includes several methods. Currently, the two most popular procedures are derived from Stewart's studies and from the bicarbonate/BE-based classical formulation. Another method, unfortunately little known, follows the Kildeberg theory applied to acid-base titration. By using the data produced by Dana Atchley in 1933, regarding electrolytes and blood gas analysis applied to diabetes, we compared the three aforementioned methods, in order to highlight their strengths and their weaknesses. The results obtained, by reprocessing the data of Atchley, have shown that Kildeberg's approach, unlike the other two methods, is consistent, rational and complete for describing the organ-physiological behavior of the hydrogen ion turnover in human organism. In contrast, the data obtained using the Stewart approach and the bicarbonate-based classical formulation are misleading and fail to specify which organs or systems are involved in causing or maintaining the diabetic acidosis. Stewart's approach, despite being considered 'quantitative', does not propose in any way the concept of 'an amount of acid' and becomes even more confusing, because it is not clear how to distinguish between 'strong' and 'weak' ions. As for Stewart's approach, the classical method makes no distinction between hydrogen ions managed by the intermediate metabolism and hydroxyl ions handled by the kidney, but, at least, it is based on the concept of titration (base-excess) and indirectly defines the concept of 'an amount of acid'. In conclusion, only Kildeberg's approach offers a complete understanding of the causes and remedies against any type of acid-base disturbance.

  15. Dimerization of HNO in aqueous solution: an interplay of solvation effects, fast acid-base equilibria, and intramolecular hydrogen bonding?

    Science.gov (United States)

    Fehling, Carsten; Friedrichs, Gernot

    2011-11-09

    The recent unraveling of the rather complex acid-base equilibrium of nitroxyl (HNO) has stimulated a renewed interest in the significance of HNO for biology and pharmacy. HNO plays an important role in enzymatic mechanisms and is discussed as a potential therapeutic agent against heart failure. A cumbersome property for studying HNO reactions, its fast dimerization leading to the rapid formation of N(2)O, is surprisingly far from being well understood. It prevents isolation and limits intermediate concentrations of nitroxyl in solution. In this study, a new mechanism for the HNO dimerization reaction in aqueous solution has been theoretically derived on the basis of DFT calculations. Detailed analysis of the initial reaction step suggests a reversal of the cis-trans isomer preference in solution compared to the corresponding gas phase reaction. In contrast to a gas phase derived model based on intramolecular rearrangement steps, an acid-base equilibrium model is in agreement with previous experimental findings and, moreover, explains the fundamental differences between the well studied gas phase reaction and the solvent reaction in terms of polarity, cis-trans isomerizations, and acidities of the intermediates. In the case of cis-hyponitrous acid, the calculated pK(a) values of the acid-base equilibria were found to be significantly different from the corresponding experimental value of the stable trans isomer. Under physiological conditions, N(2)O formation is dominated by the decomposition of the unstable monoanion cis-N(2)O(2)H(-) rather than that of the commonly stated cis-HONNOH.

  16. Influence of different storage times and temperatures on blood gas and acid-base balance in ovine venous blood

    Directory of Open Access Journals (Sweden)

    H.A. Hussein

    2013-01-01

    Full Text Available The present study was designed to investigate the effects of storage temperature and time on blood gas and acid-base balance of ovine venous blood. Ten clinically healthy sheep were used in this study. A total number of 30 blood samples, were divided into three different groups, and were stored in a refrigerator adjusted to +4 ºC (Group I, n = 10, at RT of about 22-25 ºC (Group II, n = 10 and in an incubator adjusted to 37 ºC (Group III, n = 10 for up to 48 h. Blood samples were analysed for blood gas and acid-base indices at 0, 1, 2, 3, 4, 5, 6, 12, 24 and 48 h of storage. In comparison to the baseline value (0, there were significant decreases of blood pH of samples stored at RT and in the incubator after 1 h (p<0.05, the pH value of refrigerated blood samples exhibited insignificant changes during the study (p<0.05. Mean values of pCO2 showed a significant increase in Group I and Group III after 1 h then a progressive decrease after 12 h in all Groups. Mean pO2 values were significantly higher for Group I after 2 h and for Groups II and III after 1 h (p<0.05. In general, base excess decreased significantly for all the groups during the study especially in Groups II and III. In comparison with baseline values, in all groups, bicarbonate (HCO3 increased between 1 h and 6 h (p<0.05, and later decreased at the end of the study (p<0.05. In conclusion, status of acid-base indices of the samples stored at refrigerator and RT were found within normal reference range and it may be of clinical diagnostic use for up to 6 h.

  17. Single Sodium Pyruvate Ingestion Modifies Blood Acid-Base Status and Post-Exercise Lactate Concentration in Humans

    Directory of Open Access Journals (Sweden)

    Robert A. Olek

    2014-05-01

    Full Text Available This study examined the effect of a single sodium pyruvate ingestion on a blood acid-base status and exercise metabolism markers. Nine active, but non-specifically trained, male subjects participated in the double-blind, placebo-controlled, crossover study. One hour prior to the exercise, subjects ingested either 0.1 g·kg−1 of body mass of a sodium pyruvate or placebo. The capillary blood samples were obtained at rest, 60 min after ingestion, and then three and 15 min after completing the workout protocol to analyze acid-base status and lactate, pyruvate, alanine, glucose concentrations. The pulmonary gas exchange, minute ventilation and the heart rate were measured during the exercise at a constant power output, corresponding to ~90% O2max. The blood pH, bicarbonate and the base excess were significantly higher after sodium pyruvate ingestion than in the placebo trial. The blood lactate concentration was not different after the ingestion, but the post-exercise was significantly higher in the pyruvate trial (12.9 ± 0.9 mM than in the placebo trial (10.6 ± 0.3 mM, p < 0.05 and remained elevated (nonsignificant after 15 min of recovery. The blood pyruvate, alanine and glucose concentrations, as well as the overall pulmonary gas exchange during the exercise were not affected by the pyruvate ingestion. In conclusion, the sodium pyruvate ingestion one hour before workout modified the blood acid-base status and the lactate production during the exercise.

  18. Contactless, probeless and non-titrimetric determination of acid-base reactions using broadband acoustic resonance dissolution spectroscopy (BARDS).

    Science.gov (United States)

    Ahmed, M Rizwan; McSweeney, Sean; Krüse, Jacob; Vos, Bastiaan; Fitzpatrick, Dara

    2018-02-12

    pH determination is a routine measurement in scientific laboratories worldwide. Most major advances in pH measurement were made in the 19th and early 20th century. pH measurements are critical for the determination of acid base reactions. This study demonstrates how an acid-base reaction can be monitored without the use of a pH probe, indicator and titres of reagent. The stoichiometric reaction between carbonate and HCl acid yields specific quantities of CO 2 , which causes reproducible changes to the compressibility of the solvent. This in turn slows down the speed of sound in solution which is induced by a magnetic follower gently tapping the inner wall of the vessel. As a consequence the frequencies of the acoustic resonances in the vessel are reduced. This approach is called Broadband Acoustic Resonance Dissolution Spectroscopy (BARDS) which harnesses this phenomenon for many applications. The acid-carbonate experiments have also been validated using H 2 SO 4 acid and using both potassium and sodium counterions for the carbonate. This method can be used to interrogate strong acid-base reactions in a rapid and non-invasive manner using carbonate as the base. The data demonstrate the first example of a reactant also acting as an indicator. The applicability of the method to weak acids has yet to be determined. A novel conclusion from the study is that a person with a well-trained ear is capable of determining the concentration and pH of a strong acid just by listening. This brings pH measurement into the realm of human perception.

  19. Acid-base properties of complexes with three-dimensional polyligands. Complexes with three-dimensional polyphosphoric acids

    International Nuclear Information System (INIS)

    Kopylova, V.D.; Bojko, Eh.T.; Saldadze, K.M.

    1985-01-01

    By the method of potentiometric titration acid-base properties of uranyl (2) complexes with three-dimensional polyphosphoric acids, KRF-8p, KF-1, KF-7 prepared by phosphorylation of copolymer of styrene and divinylbenzene or saponification of the copolymers of di-2,2'-chloroethyl ester of vinylphosphonic acid with divinyl benzene are studied. It is shown that in case of formation in the phase of three-dimensional polyphosphoric acids of UO 2 2+ complexes with the growth of bond covalence of metal ion-phosphonic group the acidjty of the second hydroxyl of the phosphonic group increases

  20. Studies of acid-base homeostasis during simulated weightlessness: Application of the water immersion model to man

    Science.gov (United States)

    Epstein, M.

    1975-01-01

    The effects of water immersion on acid-base homeostasis were investigated under carefully controlled conditions. Studies of renal acidification were carried out on seven healthy male subjects, each consuming a diet containing 150 meq sodium and 100 meq potassium. Control and immersion studies were carried out on each subject on the fourth and sixth days, respectively, of dietary equilibration, by which time all subjects had achieved sodium balance. The experimental protocols on study days were similar (except for the amount of water administered).

  1. The Importance of the Ionic Product for Water to Understand the Physiology of the Acid-Base Balance in Humans

    OpenAIRE

    Adeva-Andany, María M.; Carneiro-Freire, Natalia; Donapetry-García, Cristóbal; Rañal-Muíño, Eva; López-Pereiro, Yosua

    2014-01-01

    Human plasma is an aqueous solution that has to abide by chemical rules such as the principle of electrical neutrality and the constancy of the ionic product for water. These rules define the acid-base balance in the human body. According to the electroneutrality principle, plasma has to be electrically neutral and the sum of its cations equals the sum of its anions. In addition, the ionic product for water has to be constant. Therefore, the plasma concentration of hydrogen ions depends on th...

  2. [The acid-base status of preserved blood before and after processing with an oxygen-ozone mixture].

    Science.gov (United States)

    Tsyhanok, L V

    1998-12-01

    Effects were studied of oxygen and ozone mixture on the indices for the contained donor blood acid-base state. Ozonation of blood in 9 donors was carried out in different concentrations of ozone in the oxygen and ozone mixture. Revealed in blood after ozonation was increase in oxygen concentration and decrease in CO2 dissoluble fraction, with pH of blood, the content of bicarbonate being unchanged. There was no relatedness of the ozonized blood saturation with oxygen to the concentration of ozone in the oxygen and ozone mixture.

  3. An exploratory study into students' conceptual understanding of acid/base principles associated with chemical buffer systems

    Science.gov (United States)

    MacGowan, Catherine Elizabeth

    The overall objective of this research project was to provide an insight into students' conceptual understanding of acid/base principles as it relates to the comprehension and correct application of scientific concepts during a problem-solving activity. The difficulties experienced learning science and in developing appropriate problem-solving strategies most likely are predetermined by students' existing conceptual and procedural knowledge constructs; with the assimilation of newly acquired knowledge hindering or aiding the learning process. Learning chemistry requires a restructuring of content knowledge which will allow the individual to assemble and to integrate his/her own perception of science with instructional knowledge. The epistemology of constructivism, the theoretical grounding for this research project, recognizes the student's role as an active participant in the learning process. The study's design was exploratory in nature and descriptive in design. The problem-solving activity, the preparation of a chemical buffer solution at pH of 9, was selected and modified to reflect and meet the study's objective. Qualitative research methods (i.e., think aloud protocols, retrospective interviews, survey questionnaires such as the Scale of Intellectual Development (SID), and archival data sources) were used in the collection and assessment of data. Given its constructivist grounding, simplicity, and interpretative view of knowledge acquisition and learning of collegiate aged individuals, the Perry Intellectual and Ethical Development Model (1970) was chosen as the applied model for evaluation student cognition. The study's participants were twelve traditional college age students from a small, private liberal arts college. All participants volunteered for the project and had completed or were completing a general college chemistry course at the time of the project. Upon analysis of the data the following observations and results were noted: (1) students

  4. Acid base characterization of the surface of mixed species of algae Spirulin by potentiometric titration and discrete site distribution model

    OpenAIRE

    Lima, Elizabete C. de; Masini, Jorge C.

    1999-01-01

    Acid base properties of mixed species of the microalgae Spirulina were studied by potentiometric titration in medium of 0.01 and 0.10 mols L-1 NaNO3 at 25.0±0.10 C using modified Gran functions or nonlinear regression techniques for data fitting. The discrete site distribution model was used, permitting the characterization of five classes of ionizable sites in both ionic media. This fact suggests that the chemical heterogeneity of the ionizable sites on the cell surface plays a major role on...

  5. Cerebrospinal fluid acid-base status and lactate and pyruvate concentrations after convulsions of varied duration and aetiology in children.

    Science.gov (United States)

    Simpson, H; Habel, A H; George, E L

    1977-01-01

    Twenty-two infants and children were studied after convulsions of varied cause and duration. Arterial and CSF acid-base variables, lactate and pyruvate concentrations, and lactate/pyruvate ratios were measured between 3 and 18 hours after convulsive episodes. Biochemical signs of cerebral hypoxia were found in 7 patients with prolonged (greater than 30 minutes) or recurrent short convulsions. These signs were absent in patients with single short convulsions. These findings indicate that cerebral hypoxia and possible brain damage is a hazard of prolonged or rapidly recurring short convulsions. PMID:23078

  6. Enantioselective small molecule synthesis by carbon dioxide fixation using a dual Brønsted acid/base organocatalyst.

    Science.gov (United States)

    Vara, Brandon A; Struble, Thomas J; Wang, Weiwei; Dobish, Mark C; Johnston, Jeffrey N

    2015-06-17

    Carbon dioxide exhibits many of the qualities of an ideal reagent: it is nontoxic, plentiful, and inexpensive. Unlike other gaseous reagents, however, it has found limited use in enantioselective synthesis. Moreover, unprecedented is a tool that merges one of the simplest biological approaches to catalysis-Brønsted acid/base activation-with this abundant reagent. We describe a metal-free small molecule catalyst that achieves the three component reaction between a homoallylic alcohol, carbon dioxide, and an electrophilic source of iodine. Cyclic carbonates are formed enantioselectively.

  7. Stability range of MoC (hp2). II. Thermodynamic properties of generalized Lewis acid-base intermetallics

    International Nuclear Information System (INIS)

    Koukouvetakis, J.

    1988-01-01

    The γ-MoC phase with the hexagonal WC structure was prepared without the presence of metal stabilizers at temperatures below 1000 degree C. This phase was found to be thermodynamically stable at low temperatures and decomposed to Mo 2 C and graphite at 1400 K. Using equilibrium and thermodynamic data, the thermodynamic quantities of this phase were calculated. Oxide equilibration and solid-state galvanic cell experiments were used to study thermodynamic properties of binary Lewis acid-base stabilized transition-metal alloys. The activity of vanadium was determined in alloys of vanadium with platinum-group metals such as Rh, Pd, and Ir at 1000 degree C. The activities of titanium in titanium-iridium alloys and of niobium in Nb 3 Ir were determined at 1400 degree C. The ternary phase diagram of V-Pd-O at 1000 degree C was obtained. Based on the vanadium-palladium results, a partial titration curve of palladium by vanadium was constructed. The excess partial molar Gibbs free energy of vanadium at infinite dilution was found to be -36.4 kcal mol -1 at 1000 degree C. Results are in agreement with the predictions of Brewer's theory of transition-metal alloy acid-base behavior

  8. Spectroscopic Determination of Aerosol pH from Acid-Base Equilibria in Inorganic, Organic, and Mixed Systems.

    Science.gov (United States)

    Craig, Rebecca L; Nandy, Lucy; Axson, Jessica L; Dutcher, Cari S; Ault, Andrew P

    2017-08-03

    Atmospheric aerosol acidity impacts key multiphase processes, such as acid-catalyzed reactions leading to secondary organic aerosol formation, which impact climate and human health. However, traditional indirect methods of estimating aerosol pH often disagree with thermodynamic model predictions, resulting in aerosol acidity still being poorly understood in the atmosphere. Herein, a recently developed method coupling Raman microspectroscopy with extended Debye-Hückel activity calculations to directly determine the acidity of individual particles (1-15 μm projected area diameter, average 6 μm) was applied to a range of atmospherically relevant inorganic and organic acid-base equilibria systems (HNO 3 /NO 3 - , HC 2 O 4 - /C 2 O 4 2- , CH 3 COOH/CH 3 COO - , and HCO 3 - /CO 3 2- ) covering a broad pH range (-1 to 10), as well as an inorganic-organic mixture (sulfate-oxalate). Given the ionic strength of the inorganic solutions, the H + activity, γ(H + ), yielded lower values (0.68-0.75) than the organic and mixed systems (0.72-0.80). A consistent relationship between increasing peak broadness with decreasing pH was observed for acidic species, but not their conjugate bases. Greater insight into spectroscopic responses to acid-base equilibria for more complicated mixtures is still needed to understand the behavior of atmospheric aerosols.

  9. Acid-base properties of the N3 ruthenium(II) solar cell sensitizer: a combined experimental and computational analysis.

    Science.gov (United States)

    Pizzoli, Giuliano; Lobello, Maria Grazia; Carlotti, Benedetta; Elisei, Fausto; Nazeeruddin, Mohammad K; Vitillaro, Giuseppe; De Angelis, Filippo

    2012-10-14

    We report a combined spectro-photometric and computational investigation of the acid-base equilibria of the N3 solar cell sensitizer [Ru(dcbpyH(2))(2)(NCS)(2)] (dcbpyH(2) = 4,4'-dicarboxyl-2,2' bipyridine) in aqueous/ethanol solutions. The absorption spectra of N3 recorded at various pH values were analyzed by Single Value Decomposition techniques, followed by Global Fitting procedures, allowing us to identify four separate acid-base equilibria and their corresponding ground state pK(a) values. DFT/TDDFT calculations were performed for the N3 dye in solution, investigating the possible relevant species obtained by sequential deprotonation of the four dye carboxylic groups. TDDFT excited state calculations provided UV-vis absorption spectra which nicely agree with the experimental spectral shapes at various pH values. The calculated pK(a) values are also in good agreement with experimental data, within calculated energy differences a tentative assignment of the N3 deprotonation pathway is reported.

  10. Effect of potato on acid-base and mineral homeostasis in rats fed a high-sodium chloride diet.

    Science.gov (United States)

    Narcy, Agnès; Robert, Laetitia; Mazur, Andrzej; Demigné, Christian; Rémésy, Christian

    2006-05-01

    Excessive dietary NaCl in association with a paucity of plant foods, major sources of K alkaline salts, is a common feature in Western eating habits which may lead to acid-base disorders and to Ca and Mg wasting. In this context, to evaluate the effects of potato, rich in potassium citrate, on acid-base homeostasis and mineral retention, Wistar rats were fed wheat starch (WS) or cooked potato (CP) diets with a low (0.5 %) or a high (2 %) NaCl content during 3 weeks. The replacement of WS by CP in the diets resulted in a significant urinary alkalinisation (pH from 5.5 to 7.3) parallel to a rise in citrate and K excretion. Urinary Ca and Mg elimination represented respectively 17 and 62 % of the daily absorbed mineral in rats fed the high-salt WS diet compared with 5 and 28 % in rats fed the high-salt CP diet. The total SCFA concentration in the caecum was 3-fold higher in rats fed the CP diets compared with rats fed the WS diets, and it led to a significant rise in Ca and Mg intestinal absorption (Ca from 39 to 56 %; Mg from 37 to 60 %). The present model of low-grade metabolic acidosis indicates that CP may be effective in alkalinising urine, enhancing citrate excretion and ameliorating Ca and Mg balance.

  11. Application of Taguchi method for separation of uranium from acetate bearing wastewater using hydroxamic acid based sorbent

    International Nuclear Information System (INIS)

    Satpati, S.K.; Hareendran, K.; Roy, S.B.; Vaidya, A.; Bankar, V.; Dasgupta, K.; Pal, S.

    2016-01-01

    Separation and recovery of uranium from effluent of nuclear facility has drawn immense attention in separation science research. The acetic acid based uranium solution effluent generated in uranium metal powder production facility was targeted for the study. Solid state separation technique has been employed using hydroxamic acid based chelating sorbent because of several advantages. In the study, the sorbent performances have been evaluated for its important parameters like isotherm, efficiency and kinetics. The equilibrium adsorption capacity (q e ) and distribution coefficient (K d ) of U(VI) have been evaluated as 3.24 mg/g sorbent and 805 ml/g sorbent respectively. Uranium has been recovered using HCl solution. Uranium removal from the feed was found to be more than 95% and the recovery of uranium was more than 99% from the adsorbed phase. Elution process is faster than sorption process. Taguchi optimization method has been applied for designing experimental study and also to identify the optimum operational conditions for uranium separation process.The developed process is useful for separation and recovery of uranium from acetate bearing wastewater generated in uranium processing facilities

  12. Postprandial acid-base balance and ion regulation in freshwater and seawater-acclimated European flounder, Platichthys flesus.

    Science.gov (United States)

    Taylor, Josi R; Whittamore, Jonathan M; Wilson, Rod W; Grosell, Martin

    2007-08-01

    The effects of feeding on both acid-base and ion exchange with the environment, and internal acid-base and ion balance, in freshwater and seawater-acclimated flounder were investigated. Following voluntary feeding on a meal of 2.5-5% body mass and subsequent gastric acid secretion, no systemic alkaline tide or respiratory compensation was observed in either group. Ammonia efflux rates more than doubled from 489 +/- 35 and 555 +/- 64 mumol kg(-1) h(-1) under control conditions to 1,228 +/- 127 and 1,300 +/- 154 mumol kg(-1) h(-1) post-feeding in freshwater and seawater-acclimated fish, respectively. Based on predictions of gastric acid secreted during digestion, we calculated net postprandial internal base gains (i.e., HCO (3) (-) secreted from gastric parietal cells into the blood) of 3.4 mmol kg(-1) in seawater and 9.1 mmol kg(-1 )in freshwater-acclimated flounder. However, net fluxes of ammonia, titratable alkalinity, Na(+) and Cl(-) indicated that branchial Cl(-)/HCO (3) (-) and Na(+)/H(+) exchange played minimal roles in counteracting these predicted base gains and cannot explain the absence of alkaline tide. Instead, intestinal Cl(-)/HCO (3) (-) exchange appears to be enhanced after feeding in both freshwater and seawater flounder. This implicates the intestine rather than the gills as a potential route of postprandial base excretion in fish, to compensate for gastric acid secretion.

  13. Preparation of gold nanoparticles in the presence of citric acid-based dendrimers containing periphery hydroxyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Namazi, Hassan, E-mail: namazi@tabrizu.ac.ir [Research Laboratory of Dendrimers and Nanopolymers, Faculty of Chemistry, University of Tabriz, Tabriz, PO Box 51666 (Iran, Islamic Republic of); Excellence Center of New Materials and Clean Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of); Fard, Ahmad Mohammad Pour [Research Laboratory of Dendrimers and Nanopolymers, Faculty of Chemistry, University of Tabriz, Tabriz, PO Box 51666 (Iran, Islamic Republic of)

    2011-09-15

    Highlights: {yields} The most advantage of citric acid-based dendrimers is their novelty from monomeric point of view and their simple preparation method. {yields} The size and also size distribution of Au nanoparticles can be controlled through the choice of the dendrimer generation. {yields} Here, we report the preparation of the stable, isolated and uniform Au nanoparticles with using a simple method in water media.{yields} It was observed that the size of Au nanoparticles is increased with increasing the generation of dendrimer. - Abstract: In this work, Au nanoparticles were produced with reduction of HAuCl{sub 4} using NaBH{sub 4} in the presence of different generations of citric acid-based dendrimers. The greater water solubility of the newly prepared dendrimers motivated us for the preparation of Au nanoparticles in water media. Therefore, the stable, isolated and uniform type Au nanoparticles were prepared through simple process in water. UV-Vis absorption, high-resolution transmission electronic microscopy (HRTEM), electron diffraction (ED) and energy dispersive X-ray (EDX) methods were used to investigate the morphology and structure determination of the obtained gold nanoparticles.

  14. Acid base status in swamp buffaloes (Bubalus Bubalis fed rice straw and concentrate with addition of sodium

    Directory of Open Access Journals (Sweden)

    G Joseph

    2001-12-01

    Full Text Available An experiment was conducted to study the addition of NaHCO3 and Na2CO3 on acid-base status in swamp buffaloes, Three fistulated buffaloes were each introduced to dietary treatment control diett (50% rice straw + 50% concentrate, control + \\0% NaHCO3 and diet control + 10% Na2CO3 in two times Latin Square Design. The diets contained 9,7% crude protein and 53% TDN to achieve maintenance requirements of the animals. Parameters measured include (l Fed consumption, water consumption and urine volume. (2 pH in rumen fluid, saliva, bLood and urine, (3 natrium mineral content in rumen fluid, saliva, blood and urine. The results of the experiment showed higher pH in the rumen fluid, saliva, blood and urine of buffaloes due to supplementation of NaHCO3 and Na2CO3, Water consumption and urine volume was significanly increased as the effect of Na supplement. The acid-base status of buffaloes was apparently normal in all animals.

  15. Influence of different storage times and temperatures on blood gas and acid-base balance in ovine venous blood.

    Science.gov (United States)

    Hussein, H A; Aamer, A A

    2013-01-01

    The present study was designed to investigate the effects of storage temperature and time on blood gas and acid-base balance of ovine venous blood. Ten clinically healthy sheep were used in this study. A total number of 30 blood samples, were divided into three different groups, and were stored in a refrigerator adjusted to +4 ºC (Group I, n = 10), at RT of about 22-25 ºC (Group II, n = 10) and in an incubator adjusted to 37 ºC (Group III, n = 10) for up to 48 h. Blood samples were analysed for blood gas and acid-base indices at 0, 1, 2, 3, 4, 5, 6, 12, 24 and 48 h of storage. In comparison to the baseline value (0), there were significant decreases of blood pH of samples stored at RT and in the incubator after 1 h (ppO2 values were significantly higher for Group I after 2 h and for Groups II and III after 1 h (preference range and it may be of clinical diagnostic use for up to 6 h.

  16. Preparation of gold nanoparticles in the presence of citric acid-based dendrimers containing periphery hydroxyl groups

    International Nuclear Information System (INIS)

    Namazi, Hassan; Fard, Ahmad Mohammad Pour

    2011-01-01

    Highlights: → The most advantage of citric acid-based dendrimers is their novelty from monomeric point of view and their simple preparation method. → The size and also size distribution of Au nanoparticles can be controlled through the choice of the dendrimer generation. → Here, we report the preparation of the stable, isolated and uniform Au nanoparticles with using a simple method in water media.→ It was observed that the size of Au nanoparticles is increased with increasing the generation of dendrimer. - Abstract: In this work, Au nanoparticles were produced with reduction of HAuCl 4 using NaBH 4 in the presence of different generations of citric acid-based dendrimers. The greater water solubility of the newly prepared dendrimers motivated us for the preparation of Au nanoparticles in water media. Therefore, the stable, isolated and uniform type Au nanoparticles were prepared through simple process in water. UV-Vis absorption, high-resolution transmission electronic microscopy (HRTEM), electron diffraction (ED) and energy dispersive X-ray (EDX) methods were used to investigate the morphology and structure determination of the obtained gold nanoparticles.

  17. Comparison of Growth of Healthy Term Infants Fed Extensively Hydrolyzed Protein- and Amino Acid-Based Infant Formulas

    Directory of Open Access Journals (Sweden)

    Marlene W. Borschel

    2018-03-01

    Full Text Available The aim of this narrative review was to assess published growth data for healthy, term, infants consuming extensively hydrolyzed protein-based (EHF, or amino acid-based formulas (AAF. These data may be of use to clinicians managing infants with medical conditions consuming these products. A search was conducted using key terms: amino acid-based, hydrolysate, hydrolyzed, hydrolysed, infant formula, infant formulae or formulas, baby formula, or formulae or formulas, infant, infants, infantile, and growth. Seven controlled, randomized, prospective growth trials of healthy term infants fed EHFs or AAFs at similar time points during the first four months of age met these and other criteria, including that the trial was published in a peer-reviewed journal, subjects were enrolled by ≤14 days of age and were exclusively formula-fed at entry and throughout the duration of the trial, and infants were assessed at regular intervals with weight measures available ideally at 14 days, one, two, three, and four months of age. Results suggested that healthy infants receiving commonly available EHFs and AAFs do not appear to experience accelerated growth as reported for infants fed many standard formulas. Differences in growth patterns were observed with some formulas supporting normative growth patterns during the first four months but others appearing to support markedly lower growth patterns. These observations should be confirmed in well-designed prospective randomized trials. Until that time, it is recommended that EHFs and AAFs be chosen carefully with individual patient needs considered.

  18. CryoEM structure of the human SLC4A4 sodium-coupled acid-base transporter NBCe1.

    Science.gov (United States)

    Huynh, Kevin W; Jiang, Jiansen; Abuladze, Natalia; Tsirulnikov, Kirill; Kao, Liyo; Shao, Xuesi; Newman, Debra; Azimov, Rustam; Pushkin, Alexander; Zhou, Z Hong; Kurtz, Ira

    2018-03-02

    Na + -coupled acid-base transporters play essential roles in human biology. Their dysfunction has been linked to cancer, heart, and brain disease. High-resolution structures of mammalian Na + -coupled acid-base transporters are not available. The sodium-bicarbonate cotransporter NBCe1 functions in multiple organs and its mutations cause blindness, abnormal growth and blood chemistry, migraines, and impaired cognitive function. Here, we have determined the structure of the membrane domain dimer of human NBCe1 at 3.9 Å resolution by cryo electron microscopy. Our atomic model and functional mutagenesis revealed the ion accessibility pathway and the ion coordination site, the latter containing residues involved in human disease-causing mutations. We identified a small number of residues within the ion coordination site whose modification transformed NBCe1 into an anion exchanger. Our data suggest that symporters and exchangers utilize comparable transport machinery and that subtle differences in their substrate-binding regions have very significant effects on their transport mode.

  19. Dipicolinate complexes of main group metals with hydrazinium cation

    Indian Academy of Sciences (India)

    Unknown

    The capacity of pyridine carboxylic acids to act as ligand is an important property, relevant in several areas of ... There are, however, a few examples of other coordination modes of. *For correspondence ... powdered solid formed after 24 h was filtered out and the filtrate was reduced to 25 ml volume and left at room ...

  20. Acid-base regulation, metabolism and energetics in sipunculus nudus as a function of ambient carbon dioxide level

    Science.gov (United States)

    PORtner; ReipschlAGerY; n

    1998-01-01

    Changes in the rates of oxygen consumption and ammonium excretion, in intra- and extracellular acid-base status and in the rate of H+-equivalent ion transfer between animals and ambient water were measured during environmental hypercapnia in the peanut worm Sipunculus nudus. During exposure to 1 % CO2 in air, intracellular and coelomic plasma PCO2 values rose to levels above those expected from the increase in ambient CO2 tension. Simultaneously, coelomic plasma PO2 was reduced below control values. The rise in PCO2 also induced a fall in intra- and extracellular pH, but intracellular pH was rapidly and completely restored. This was achieved during the early period of hypercapnia at the expense of a non-respiratory increase in the extracellular acidosis. The pH of the extracellular space was only partially compensated (by 37 %) during long-term hypercapnia. The net release of basic equivalents under control conditions turned to a net release of protons to the ambient water before a net, albeit reduced, rate of base release was re-established after a new steady state had been achieved with respect to acid-base parameters. Hypercapnia also affected the mode and rate of metabolism. It caused the rate of oxygen consumption to fall, whereas the rate of ammonium excretion remained constant or even increased, reflecting a reduction of the O/N ratio in both cases. The transient intracellular acidosis preceded a depletion of the phosphagen phospho-l-arginine, an accumulation of free ADP and a decrease in the level of Gibbs free energy change of ATP hydrolysis, before replenishment of phosphagen and restoration of pHi and energy status occurred in parallel. In conclusion, long-term hypercapnia in vivo causes metabolic depression, a parallel shift in acid-base status and increased gas partial pressure gradients, which are related to a reduction in ventilatory activity. The steady-state rise in H+-equivalent ion transfer to the environment reflects an increased rate of

  1. Associations between Dietary Acid-Base Load and Cardiometabolic Risk Factors in Adults: The Tehran Lipid and Glucose Study

    Directory of Open Access Journals (Sweden)

    Zahra Bahadoran

    2015-06-01

    Full Text Available BackgroundIn this study we investigated the associations of dietary acid-base load, identified by potential renal acid load (PRAL and protein to potassium (Pro:K ratio, with cardiometabolic risk factors in Tehranian adults.MethodsA cross-sectional study was conducted within the framework of the fourth phase of the Tehran Lipid and Glucose Study (2009 to 2011 on 5,620 men and women aged 19 to 70 years. Dietary data were collected by a trained dietitian using a validated, 147-food item, semi-quantitative food frequency questionnaire, and dietary PRAL and Pro:K ratio were calculated. Multiple linear regression models with adjustment for potential confounding variables were used to evaluate the associations of dietary acid-base load with anthropometric measures, blood pressure, serum triglycerides, high density lipoprotein cholesterol (HDL-C, serum creatinine, and fasting blood glucose.ResultsThe mean±SD age of the participants was 39.8±12.8 years and 54% of participants were women. Mean±SD PRAL was -22.0±29.1; mean PRAL was -15.6 in men and -26.8 in women. Dietary PRAL was associated with weight (β=0.098, P<0.001, waist circumference (β=0.062, P<0.01, serum triglycerides (β=0.143, P<0.01, HDL-C (β=-0.11, P<0.01, diastolic blood pressure (β=0.062, P<0.01, and serum creatinine (β=0.142, P<0.001. Pro:K ratio was associated with weight (β=0.055, P<0.001, waist circumference (β=0.04, P<0.01, serum HDL-C (β=-0.06, P<0.01, serum triglycerides (β=0.03, P<0.05, diastolic blood pressure (β=0.026, P<0.05, and serum creatinine (β=0.07, P<0.01.ConclusionA more acidic dietary acid-base load may be a risk factor for the development of metabolic disorders.

  2. Acid-base properties of the alumina surface: influence of the titration procedures on the microcalorimetric results.

    Science.gov (United States)

    Morel, Jean-Pierre; Marmier, Nicolas; Hurel, Charlotte; Morel-Desrosiers, Nicole

    2009-10-01

    The enthalpy changes associated with the protonation and deprotonation of an alumina surface have been determined on the basis of microcalorimetry experiments and acid-base potentiometric titrations at 25 degrees C. It has been shown that the results may vary significantly according to the experimental procedure. In order to do so, the potentiometric and microcalorimetric titrations have been carried out first from an acidic pH to basic pH and second from a pH near the pH(zpc) of alumina to acidic or basic pH. It has been demonstrated that the pK(a) values deduced from the potentiometric titrations are the same whatever the experimental protocol whereas the only way to obtain meaningful enthalpies of proton exchange is to carry out microcalorimetric titrations by starting around the point of zero charge.

  3. Protein remains stable at unusually high temperatures when solvated in aqueous mixtures of amino acid based ionic liquids

    DEFF Research Database (Denmark)

    Chevrot, Guillaume; Fileti, Eudes Eterno; Chaban, Vitaly V.

    2016-01-01

    Using molecular dynamics simulations, we investigated the thermal stability and real-time denaturation of a model mini-protein in four solvents: (1) water, (2) 1-ethyl-3-methylimidazolium alaninate [EMIM][ALA] (5 mol% in water), (3) methioninate [EMIM][MET] (5 mol% in water), and (4) tryptophanate...... [EMIM][TRP] (5 mol% in water). Upon analyzing the radius of gyration, the solvent-accessible surface area, root-mean-squared deviations, and inter- and intramolecular hydrogen bonds, we found that the mini-protein remains stable at 30–40 K higher temperatures in aqueous amino acid based ionic liquids...... (AAILs) than in water. This thermal stability was correlated with the thermodynamics and shear viscosity of the AAIL-containing mixtures. These results suggest that AAILs are generally favorable for protein conservation. [Figure not available: see fulltext.]...

  4. The Comparative Studies of Binding Activity of Curcumin and Didemethylated Curcumin with Selenite: Hydrogen Bonding vs Acid-Base Interactions.

    Science.gov (United States)

    Liao, Jiahn-Haur; Wu, Tzu-Hua; Chen, Ming-Yi; Chen, Wei-Ting; Lu, Shou-Yun; Wang, Yi-Hsuan; Wang, Shao-Pin; Hsu, Yen-Min; Huang, Yi-Shiang; Huang, Zih-You; Lin, Yu-Ching; Chang, Ching-Ming; Huang, Fu-Yung; Wu, Shih-Hsiung

    2015-12-04

    In this report, the in vitro relative capabilities of curcumin (CCM) and didemethylated curcumin (DCCM) in preventing the selenite-induced crystallin aggregation were investigated by turbidity tests and isothermal titration calorimetry (ITC). DCCM showed better activity than CCM. The conformers of CCM/SeO3(2-) and DCCM/SeO3(2-) complexes were optimized by molecular orbital calculations. Results reveal that the selenite anion surrounded by CCM through the H-bonding between CCM and selenite, which is also observed via IR and NMR studied. For DCCM, the primary driving force is the formation of an acid-base adduct with selenite showing that the phenolic OH group of DCCM was responsible for forming major conformer of DCCM. The formation mechanisms of selenite complexes with CCM or DCCM explain why DCCM has greater activity than CCM in extenuating the toxicity of selenite as to prevent selenite-induced lens protein aggregation.

  5. The Acid/Base Surface Characterization of Sandstone, Limestone and Marble and its Effect upon the Polymerisation of Tetraethoxysilane

    Directory of Open Access Journals (Sweden)

    Elizabeth S. Goins

    1994-11-01

    Full Text Available The conservation of historically important stone buildings and monuments is a complicated field that crosses the boundaries of several different disciplines; in particular chemistry, geology, biology and materials science. It is a fact of nature that materials decay, and the role of the conservator is to delay this process for as long as possible. One way of approaching the problem is to place the object in a controlled environment. This is, however, clearly impossible in the case of large objects, and is expensive for smaller objects. The problem has become of increasing concern as decay mechanisms seem to have accelerated along with urban activity - primarily industrialisation and the burning of fossil fuels. This study focuses on a preliminary investigation of the acid/base nature of some building stones in order to determine their effect upon the polymerisation processes of an alkoxysilane system.

  6. Electrical, dielectric and electrochemical characterization of novel poly(acrylic acid)-based polymer electrolytes complexed with lithium tetrafluoroborate

    Science.gov (United States)

    Ngai, Koh Sing; Ramesh, S.; Ramesh, K.; Juan, Joon Ching

    2018-01-01

    A series of novel poly(acrylic acid)-based polymer electrolytes with high conductivities at room temperature has been prepared and studied. Polymer electrolytes composed of poly(acrylic acid) (PAA) and lithium tetrafluoroborate (LiBF4) were prepared by means of solution casting. The effect of the addition of LiBF4 on the properties of the PAA-based electrolyte matrices was analysed and investigated using impedance spectroscopy. The optimized PAA-based solid electrolyte showed an electrochemical stability window of 3.2 V. Thermogravimetric analysis indicated that the incorporation of LiBF4 into PAA matrix enhances the thermal stability. The structural properties of polymer electrolytes were studied by using X-ray diffraction analysis.

  7. [SPECTRAL AND ACID-BASE PROPERTIES OF HEMOLYMPH PLASMA AND ITS FRACTIONS FROM GASTROPOD PULMONATE MOLLUSC ACHATINA FULICA].

    Science.gov (United States)

    Petrova, T A; Lianguzov, A Yu; Malygina, N M

    2016-01-01

    The set of normal biochemical indicators of the hemolymph plasma of gastropod pulmonate mollusc Achatinafulica is described. Comparative analysis of the whole plasma and its subfractions enriched and depleted of oxygen-carrying protein hemocyanin was performed by spectrophotometry and spectrofluorimetry methods. Individual features of the absorption spectra were analyzed using fourth derivatives. The optimum method for estimating protein concentration was chosen. To characterize acid-base properties of plasma hemolymph and its sub-fractions we calculated buffer capacity, equivalence points and pK values of dominant buffer groups. It is shown that the major role in maintaining the buffer capacity of hemolymph belongs to the bicarbonate system. These results are compared with data for Helix pomatia available in literature. In the future the indicators studied in this work will be used to develop ecotoxicological criteria for the environmental assessment.

  8. The Comparative Studies of Binding Activity of Curcumin and Didemethylated Curcumin with Selenite: Hydrogen Bonding vs Acid-Base Interactions

    Science.gov (United States)

    Liao, Jiahn-Haur; Wu, Tzu-Hua; Chen, Ming-Yi; Chen, Wei-Ting; Lu, Shou-Yun; Wang, Yi-Hsuan; Wang, Shao-Pin; Hsu, Yen-Min; Huang, Yi-Shiang; Huang, Zih-You; Lin, Yu-Ching; Chang, Ching-Ming; Huang, Fu-Yung; Wu, Shih-Hsiung

    2015-12-01

    In this report, the in vitro relative capabilities of curcumin (CCM) and didemethylated curcumin (DCCM) in preventing the selenite-induced crystallin aggregation were investigated by turbidity tests and isothermal titration calorimetry (ITC). DCCM showed better activity than CCM. The conformers of CCM/SeO32- and DCCM/SeO32- complexes were optimized by molecular orbital calculations. Results reveal that the selenite anion surrounded by CCM through the H-bonding between CCM and selenite, which is also observed via IR and NMR studied. For DCCM, the primary driving force is the formation of an acid-base adduct with selenite showing that the phenolic OH group of DCCM was responsible for forming major conformer of DCCM. The formation mechanisms of selenite complexes with CCM or DCCM explain why DCCM has greater activity than CCM in extenuating the toxicity of selenite as to prevent selenite-induced lens protein aggregation.

  9. Restoration of Respiratory Gases and Acid-base Balance of Blood of Gamma Irradiated Rats Through Bone Marrow Transplantation

    International Nuclear Information System (INIS)

    Eissa, S.M.; Roushdy, H.M.; Khamis, F. I.; Abu-Zeid, N.M.

    2000-01-01

    The present investigation aimed at elucidating the role played by bone marrow transplantation as a biological treatment against the deleterious effect of ionizing radiation. The parameters tested were PO2; PCO2; TCO2 and acid base balance encountering pH and (HCO3) in blood. Investigations were conducted 1,3,7,14 and 21 days post whole body gamma exposure at the dose levels 2 and 6 Gy. The data obtained showed highly significant changes in all tested parameters after whole body gamma irradiation. A higher depressant effect was more pronounced after exposure to higher radiation dose. Bone marrow transplantation to irradiated rats resulted in partial restoration or the radiation induced changes in both PO2 and PCO2 as recorded on the first week post treatment and succeeded to ameliorate the radiation induced changes in pH values and (HCO3) in blood

  10. Poly(amino acid)-Based Gel Fibers with pH Responsivity by Coaxial Reactive Electrospinning.

    Science.gov (United States)

    Molnar, Kristof; Jedlovszky-Hajdu, Angela; Zrinyi, Miklos; Jiang, Shaohua; Agarwal, Seema

    2017-07-01

    Electrospinning is a well-known technique for the preparation of scaffolds for biomedical applications. In this work, a continuous electrospinning method for gel fiber preparation is presented without a spinning window. As proof of concept, the preparation of poly(aspartic acid)-based hydrogel fibers and their properties are described by using poly(succinimide) as shell polymer and 2,2,4(2,4,4)-trimethyl-1,6-hexanediamine as cross-linker in the core of the nozzle. Cross-linking takes place as the two solutions get in contact at the tip of the nozzle. The impact of solution concentrations and feeding rates on fiber morphology, proof of the presence of cross-links as well as pH sensitivity after the transformation of the poly(succinimide)-based material to poly(aspartic acid) is presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Peculiarities of Cell Seeding on Polylactic Acid-Based Scaffolds Fabricated Using Electrospinning and Solution Blow Spinning Technologies.

    Science.gov (United States)

    Afanasiev, S A; Muslimova, E F; Nashchekina, Yu A; Nikonov, P O; Rogovskaya, Yu V; Bolbasov, E N; Tverdokhlebov, S I

    2017-12-01

    We studied the possibility of seeding bone marrow-derived stromal cells onto polylactic acid-based scaffolds fabricated by electrospinning and solution blow spinning technologies. The cells were applied to the scaffolds by dynamic seeding and scaffolds were then cultured in Petri dishes in culture medium for 3 days. Cell migration to the Petri dish surface was noted only for scaffolds fabricated by electrospinning technology, but DAPI staining confirmed the presence of cells in both scaffolds. The mean number of cells in scaffolds fabricated by electrospinning and solution blow spinning was 56±9 and 81±6, respectively. The scaffold fabricated by solution blow spinning was more effectively (p<0.05) colonized by cells due to its more optimal spatial structure.

  12. Validity and Practitality of Acid-Base Module Based on Guided Discovery Learning for Senior High School

    Science.gov (United States)

    Yerimadesi; Bayharti; Jannah, S. M.; Lufri; Festiyed; Kiram, Y.

    2018-04-01

    This Research and Development(R&D) aims to produce guided discovery learning based module on topic of acid-base and determine its validity and practicality in learning. Module development used Four D (4-D) model (define, design, develop and disseminate).This research was performed until development stage. Research’s instruments were validity and practicality questionnaires. Module was validated by five experts (three chemistry lecturers of Universitas Negeri Padang and two chemistry teachers of SMAN 9 Padang). Practicality test was done by two chemistry teachers and 30 students of SMAN 9 Padang. Kappa Cohen’s was used to analyze validity and practicality. The average moment kappa was 0.86 for validity and those for practicality were 0.85 by teachers and 0.76 by students revealing high category. It can be concluded that validity and practicality was proven for high school chemistry learning.

  13. A one-step colorimetric acid-base titration sensor using a complementary color changing coordination system.

    Science.gov (United States)

    Cho, Hui Hun; Kim, Si Hyun; Heo, Jun Hyuk; Moon, Young Eel; Choi, Young Hun; Lim, Dong Cheol; Han, Kwon-Hoon; Lee, Jung Heon

    2016-06-21

    We report the development of a colorimetric sensor that allows for the quantitative measurement of the acid content via acid-base titration in a single-step. In order to create the sensor, we used a cobalt coordination system (Co-complex sensor) that changes from greenish blue colored Co(H2O)4(OH)2 to pink colored Co(H2O)6(2+) after neutralization. Greenish blue and pink are two complementary colors with a strong contrast. As a certain amount of acid is introduced to the Co-complex sensor, a portion of greenish blue colored Co(H2O)4(OH)2 changes to pink colored Co(H2O)6(2+), producing a different color. As the ratio of greenish blue and pink in the Co-complex sensor is determined by the amount of neutralization reaction occurring between Co(H2O)4(OH)2 and an acid, the sensor produced a spectrum of green, yellow green, brown, orange, and pink colors depending on the acid content. In contrast, the color change appeared only beyond the end point for normal acid-base titration. When we mixed this Co-complex sensor with different concentrations of citric acid, tartaric acid, and malic acid, three representative organic acids in fruits, we observed distinct color changes for each sample. This color change could also be observed in real fruit juice. When we treated the Co-complex sensor with real tangerine juice, it generated diverse colors depending on the concentration of citric acid in each sample. These results provide a new angle on simple but quantitative measurements of analytes for on-site usage in various applications, such as in food, farms, and the drug industry.

  14. Profile of acid-base disturbances in an intensive care unit of Fortaleza, Ceará, Brazil.

    Directory of Open Access Journals (Sweden)

    Renan Barbosa Rodrigues

    2014-09-01

    Full Text Available Introduction: Acid – base disturbances are entities caused by the deregulation of the concentration of bicarbonate ions, the concentration of hydrogen ions and the partial pressure of carbon dioxide in the blood. These disturbances modify most cell fuctions when present, jeopardizing the proper functioning of organs.Methods: Cross-sectional analytical study based upon data collected from medical files of patients in ICU as seen from August 1 to December 31, 2013 at the Dr. José Frota Institute in Fortaleza, Ceará. The variables studied were: age, sex, cause of ICU admission, pH, HCO3-, pO2, pCO2 , glomerular filtration rate ( GFR , serum potassium concentrarion, serum magnesium concentration, serum creatinine and hemoglobin levels.Results: The most frequent disorders were primary respiratory alkalosis with               33 ( 38,4 % cases, 30 ( 34,9 % of metabolic alkalosis, 13 ( 15.1% of metabolic acidosis,    7 ( 8,2% did not present acid-base disorders and respiratory acidosis           3 ( 3,5%. Patients admitted with TBI had respiratory alkalosis as the most common primary disorder, followed by metabolic alkalosis, 16 ( 47,0 % and 13 ( 38,2 % , respectively. The main disturbances were mixed respiratory alkalosis with metabolic alkalosis and respiratory alkalosis with metabolic alkalosis found in 15.12% of patients in each of these combinations. Conclusion:The importance  of a detailed evaluation of acid-base disturbances is necessary since these disorders lead to higher mortality rates, so it is necessary to establish the main types of disorders that are associated with a particular cause of hospitalization .

  15. Effects of humic acid-based buffer + cation on chemical characteristics of saline soils and maize growth

    Directory of Open Access Journals (Sweden)

    W. Mindari

    2014-10-01

    Full Text Available Humic acid is believed to maintain the stability of the soil reaction, adsorption / fixation / chelate of cation, thereby increasing the availability of water and plant nutrients. On the other hand, the dynamics of saline soil cation is strongly influenced by the change of seasons that disrupt water and plant nutrients uptake. This experiment was aimed to examine the characteristics of the humic acid from compost, coal, and peat and its function in the adsorption of K+ and NH4+ cations, thus increasing the availability of nutrients and of maize growth. Eighteen treatments consisted of three humic acid sources (compost, peat and coal, two cation additives (K+ and NH4+, and three doses of humic acid-based buffer (10, 20, and 30 g / 3kg, were arranged in a factorial completely randomized with three replicates. The treatments were evaluated against changes in pH, electric conductivity (EC, cation exchange capacity (CEC, chlorophyll content, plant dry weight and plant height. The results showed that the addition of K+ and NH4+ affected pH, CEC, K+, NH4+, and water content of the buffer. Application of humic acid-based buffer significantly decreased soil pH from > 7 to about 6.3, decreased soil EC to 0.9 mS / cm, and increased exchangeable Na from 0.40 to 0.56 me / 100g soil, Ca from 15.57 to 20.21 me/100 g soil, Mg from 1.76 to 6.52 me/100 g soil, and K from 0.05-0.51 me / 100g soil. Plant growth (plant height, chlorophyll content, leaf area, and stem weight at 35 days after planting increased with increasing dose of humic acid. The dose of 2.0g peat humic acid + NH4+ / 3 kg of soil or 30g peat humic acid + K+ / 3 kg of oil gave the best results of maize growth.

  16. Acid-base buffering of soils in transitional and transitional-accumulative positions of undisturbed southern-taiga landscapes

    Science.gov (United States)

    Rusakova, E. S.; Ishkova, I. V.; Tolpeshta, I. I.; Sokolova, T. A.

    2012-05-01

    The method of continuous potentiometric titration (CPT) of soil water suspensions was used to evaluate the acid-base buffering of samples from the major genetic horizons of podzolic soils on a slope and soddy gley soils on the adjacent floodplain of a rivulet. In the soils of the slope, the buffering to acid upon titration from the pH of the initial titration point (ITP) to pH 3 in all the horizons was 1.5-2.0 times lower than that in the podzolic soils of the leveled interfluve, which could be due to the active leaching of exchangeable bases and oxalate-soluble aluminum and iron compounds with the later soil flows. In the soddy gley soils, the buffering to acid in the mineral horizons was 2-10 times higher than that in the podzolic soils. A direct dependence of the soil buffering to acid on the total content of exchangeable bases and on the content of oxalate-soluble aluminum compounds was found. A direct dependence of the buffering to basic upon titration from the ITP to pH 10 on the contents of the oxalate-soluble aluminum and organic matter was observed in the mineral horizons of all the studied soils. The soil treatment with Tamm's reagent resulted in the decrease of the buffering to acid in the soddy gley soils of the floodplain, as well as in the decrease of the buffering to basic in the soils on the slopes and in the soddy gley soils. It was also found that the redistribution of the mobile aluminum compounds between the eluvial, transitional, and transitional-accumulative positions in the undisturbed southern taiga landscapes leads to significant spatial differentiation of the acid-base buffering of the mineral soil horizons with a considerable increase in the buffer capacity of the soils within the transitional-accumulative terrain positions.

  17. Acidic deposition: State of science and technology. Report 14. Methods for projecting future changes in surface water acid-base chemistry. Final report

    International Nuclear Information System (INIS)

    Thornton, K.W.; Marmorek, D.; Ryan, P.F.; Heltcher, K.; Robinson, D.

    1990-09-01

    The objectives of the report are to: critically evaluate methods for projecting future effects of acidic deposition on surface water acid-base chemistry; review and evaluate techniques and procedures for analyzing projection uncertainty; review procedures for estimating regional lake and stream population attributes; review the U.S. Environmental Protection Agency (EPA) Direct/Delayed Response Project (DDRP) methodology for projecting the effects of acidic deposition on future changes in surface water acid-base chemistry; and present the models, uncertainty estimators, population estimators, and proposed approach selected to project the effects of acidic deposition on future changes in surface water acid-base chemistry in the NAPAP 1990 Integrated Assessment and discuss the selection rationale

  18. Aerosol Fragmentation Driven by Coupling of Acid-Base and Free-Radical Chemistry in the Heterogeneous Oxidation of Aqueous Citric Acid by OH Radicals.

    Science.gov (United States)

    Liu, Matthew J; Wiegel, Aaron A; Wilson, Kevin R; Houle, Frances A

    2017-08-10

    A key uncertainty in the heterogeneous oxidation of carboxylic acids by hydroxyl radicals (OH) in aqueous-phase aerosol is how the free-radical reaction pathways might be altered by acid-base chemistry. In particular, if acid-base reactions occur concurrently with acyloxy radical formation and unimolecular decomposition of alkoxy radicals, there is a possibility that differences in reaction pathways impact the partitioning of organic carbon between the gas and aqueous phases. To examine these questions, a kinetic model is developed for the OH-initiated oxidation of citric acid aerosol at high relative humidity. The reaction scheme, containing both free-radical and acid-base elementary reaction steps with physically validated rate coefficients, accurately predicts the experimentally observed molecular composition, particle size, and average elemental composition of the aerosol upon oxidation. The difference between the two reaction channels centers on the reactivity of carboxylic acid groups. Free-radical reactions mainly add functional groups to the carbon skeleton of neutral citric acid, because carboxylic acid moieties deactivate the unimolecular fragmentation of alkoxy radicals. In contrast, the conjugate carboxylate groups originating from acid-base equilibria activate both acyloxy radical formation and carbon-carbon bond scission of alkoxy radicals, leading to the formation of low molecular weight, highly oxidized products such as oxalic and mesoxalic acid. Subsequent hydration of carbonyl groups in the oxidized products increases the aerosol hygroscopicity and accelerates the substantial water uptake and volume growth that accompany oxidation. These results frame the oxidative lifecycle of atmospheric aerosol: it is governed by feedbacks between reactions that first increase the particle oxidation state, then eventually promote water uptake and acid-base chemistry. When coupled to free-radical reactions, acid-base channels lead to formation of low molecular

  19. Changes in the acid-base balance and lactate concentration in the blood in amateur ultramarathon runners during a 100-km run.

    Science.gov (United States)

    Jastrzębski, Z; Żychowska, M; Konieczna, A; Ratkowski, W; Radzimiński, Ł

    2015-09-01

    The aim of this study was to analyse the acid-base balance and partial pressure of blood gases of participants during a 100-km run. Fourteen experienced amateur ultramarathon runners (age: 43.36±11.83 years; height: 175.29±6.98 cm; weight: 72.12±7.36 kg) completed the 100-km run. Blood samples were taken before the run; after 25, 50, 75, and 100 km; and 12 and 24 hours after the run. There were significant differences (pamateurs runners are able to adjust their running speed so as not to provoke a significant acid-base imbalance or lactate acid accumulation.

  20. Comparative acid-base properties of the surface of components of the CdTe-ZnS system in series of substitutional solid solutions and their analogs

    Science.gov (United States)

    Kirovskaya, I. A.; Kasatova, I. Yu.

    2011-07-01

    The acid-base properties of the surface of solid solutions and binary components of the CdTe-ZnS system are studied by hydrolytic adsorption, nonaqueous conductometric titration, mechanochemistry, IR spectroscopy, and Raman scattering spectroscopy. The strength, nature, and concentration of acid centers on the original surface and that exposed to CO are determined. The changes in acid-base properties in dependence on the composition of the system under investigation in the series of CdB6, ZnB6 analogs are studied.