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Sample records for acid based quantitative

  1. Design of cinnamaldehyde amino acid Schiff base compounds based on the quantitative structure–activity relationship

    Science.gov (United States)

    Hui Wang; Mingyue Jiang; Shujun Li; Chung-Yun Hse; Chunde Jin; Fangli Sun; Zhuo Li

    2017-01-01

    Cinnamaldehyde amino acid Schiff base (CAAS) is a new class of safe, bioactive compounds which could be developed as potential antifungal agents for fungal infections. To design new cinnamaldehyde amino acid Schiff base compounds with high bioactivity, the quantitative structure–activity relationships (QSARs) for CAAS compounds against Aspergillus niger (A. niger) and...

  2. 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

  3. Quantitative rRNA-targeted solution-based hybridization assay using peptide nucleic acid molecular beacons.

    Science.gov (United States)

    Li, Xu; Morgenroth, Eberhard; Raskin, Lutgarde

    2008-12-01

    The potential of a solution-based hybridization assay using peptide nucleic acid (PNA) molecular beacon (MB) probes to quantify 16S rRNA of specific populations in RNA extracts of environmental samples was evaluated by designing PNA MB probes for the genera Dechloromonas and Dechlorosoma. In a kinetic study with 16S rRNA from pure cultures, the hybridization of PNA MB to target 16S rRNA exhibited a higher final hybridization signal and a lower apparent rate constant than the hybridizations to nontarget 16S rRNAs. A concentration of 10 mM NaCl in the hybridization buffer was found to be optimal for maximizing the difference between final hybridization signals from target and nontarget 16S rRNAs. Hybridization temperatures and formamide concentrations in hybridization buffers were optimized to minimize signals from hybridizations of PNA MB to nontarget 16S rRNAs. The detection limit of the PNA MB hybridization assay was determined to be 1.6 nM of 16S rRNA. To establish proof for the application of PNA MB hybridization assays in complex systems, target 16S rRNA from Dechlorosoma suillum was spiked at different levels to RNA isolated from an environmental (bioreactor) sample, and the PNA MB assay enabled effective quantification of the D. suillum RNA in this complex mixture. For another environmental sample, the quantitative results from the PNA MB hybridization assay were compared with those from clone libraries.

  4. Typing of unknown microorganisms based on quantitative analysis of fatty acids by mass spectrometry and hierarchical clustering

    Energy Technology Data Exchange (ETDEWEB)

    Li Tingting; Dai Ling; Li Lun; Hu Xuejiao; Dong Linjie; Li Jianjian; Salim, Sule Khalfan; Fu Jieying [Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079 (China); Zhong Hongying, E-mail: hyzhong@mail.ccnu.edu.cn [Key Laboratory of Pesticides and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, Hubei 430079 (China)

    2011-01-17

    Rapid identification of unknown microorganisms of clinical and agricultural importance is not only critical for accurate diagnosis of infections but also essential for appropriate and prompt treatment. We describe here a rapid method for microorganisms typing based on quantitative analysis of fatty acids by iFAT approach (Isotope-coded Fatty Acid Transmethylation). In this work, lyophilized cell lysates were directly mixed with 0.5 M NaOH solution in d3-methanol and n-hexane. After 1 min of ultrasonication, the top n-hexane layer was combined with a mixture of standard d0-methanol derived fatty acid methylesters with known concentration. Measurement of intensity ratios of d3/d0 labeled fragment ion and molecular ion pairs at the corresponding target fatty acids provides a quantitative basis for hierarchical clustering. In the resultant dendrogram, the Euclidean distance between unknown species and known species quantitatively reveals their differences or shared similarities in fatty acid related pathways. It is of particular interest to apply this method for typing fungal species because fungi has distinguished lipid biosynthetic pathways that have been targeted for lots of drugs or fungicides compared with bacteria and animals. The proposed method has no dependence on the availability of genome or proteome databases. Therefore, it is can be applicable for a broad range of unknown microorganisms or mutant species.

  5. Compositional characteristics of commercial yoghurt based on quantitative determination of viable lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Niketić Gordana B.

    2009-01-01

    Full Text Available Yoghurt quality is particularly difficult to standardize because of the many forms, varieties, manufacturing methods, ingredients and consumer preferences that exist. Since these factors will always play an important role, it is unlikely that a uniform yoghurt quality concept will ever emerge, such as has been developed for other dairy products. There are a number of common denominators, however that have bearing on yoghurt quality. Since a number of producers are recognized within the broad category entitled yoghurt. This situation makes yoghurt an interesting, challenging, but also a confusing area to work in. The present investigation was undertaken to isolate from commercial yoghurt the strains involved in its manufacture and determine the characteristics of Streptococcus thermophilus and Lactobacillus delbrueckii subsp.bulgaricus. This study is concerned with the lactic acid bacteria (L.delbrueckii subsp. bulgaricus and S. thermophilus growth in yoghurt from involving different procedures and with the determination of the number of lactic acid bacteria in dependence of the temperature and acidity in the period of storage. Predominant samples of yoghurt were with 11-107/ml lactic acid lactococci (44.28%.

  6. Quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria by gas chromatography-mass spectrometry.

    Science.gov (United States)

    Guan, Wenna; Zhao, Hui; Lu, Xuefeng; Wang, Cong; Yang, Menglong; Bai, Fali

    2011-11-11

    Simple and rapid quantitative determination of fatty-acid-based biofuels is greatly important for the study of genetic engineering progress for biofuels production by microalgae. Ideal biofuels produced from biological systems should be chemically similar to petroleum, like fatty-acid-based molecules including free fatty acids, fatty acid methyl esters, fatty acid ethyl esters, fatty alcohols and fatty alkanes. This study founded a gas chromatography-mass spectrometry (GC-MS) method for simultaneous quantification of seven free fatty acids, nine fatty acid methyl esters, five fatty acid ethyl esters, five fatty alcohols and three fatty alkanes produced by wild-type Synechocystis PCC 6803 and its genetically engineered strain. Data obtained from GC-MS analyses were quantified using internal standard peak area comparisons. The linearity, limit of detection (LOD) and precision (RSD) of the method were evaluated. The results demonstrated that fatty-acid-based biofuels can be directly determined by GC-MS without derivation. Therefore, rapid and reliable quantitative analysis of fatty-acid-based biofuels produced by wild-type and genetically engineered cyanobacteria can be achieved using the GC-MS method founded in this work. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Qualitative and quantitative electroanalysis of synthetic phenolic antioxidant mixtures in edible oils based on their acid-base properties.

    Science.gov (United States)

    Noel Robledo, Sebastian; Alicia Zón, María; Daniel Ceballos, Claudio; Fernández, Héctor

    2011-08-01

    A simple electroanalytical method using square wave voltammetry at a Pt band ultramicroelectrode to perform a qualitative and quantitative analysis of different synthetic antioxidant mixtures permitted by official regulations in edible oils is proposed. The methodology was based on the comparison of voltammetric signals obtained in acetonitrile+0.1M (C4H9)4NF6P with those recorded in the same reaction medium when different aliquots of (C4H9)4NOH were added to allow a qualitative differentiation between antioxidants. Firstly, studies on solutions prepared from commercial reagents were carried out. Then, the results obtained were transferred to the analysis of a real matrix, i.e., an edible olive oil. From real samples spiked with a known amount of different synthetic antioxidant mixtures, we could deduce the presence of these antioxidants by comparing results obtained in the neutral medium with those obtained after the successive addition of base. The standard addition method was used to quantify the individually spiked synthetic antioxidants in the real sample. Recovery percentages were between 88% and 118%. The reproducibility was 1.5%, 3.1%, 4.1% and 4.1% in ACN+0.1M TBAHFP and 1.5%, 4.6%, 6.6% and 2.5% in Bz/EtOH (1:2)+0.1M H2SO4 for TBHQ, BHA, BHT and PG, respectively. The repeatability was 1% for PG in both media. These parameters show a good system performance.

  8. Quantitative profiling of bile acids in biofluids and tissues based on accurate mass high resolution LC-FT-MS: Compound class targeting in a metabolomics workflow

    NARCIS (Netherlands)

    Bobeldijk, I.; Hekman, M.; Vries de- Weij, J.van der; Coulier, L.; Ramaker, R.; Kleemann, R.; Kooistra, T.; Rubingh, C.; Freidig, A.; Verheij, E.

    2008-01-01

    We report a sensitive, generic method for quantitative profiling of bile acids and other endogenous metabolites in small quantities of various biological fluids and tissues. The method is based on a straightforward sample preparation, separation by reversed-phase high performance liquid-chromatograp

  9. Detection and identification of human Plasmodium species with real-time quantitative nucleic acid sequence-based amplification

    Directory of Open Access Journals (Sweden)

    Kager Piet A

    2006-10-01

    Full Text Available Abstract Background Decisions concerning malaria treatment depend on species identification causing disease. Microscopy is most frequently used, but at low parasitaemia (Plasmodium antigen detection do often not allow for species discrimination as microscopy does, but also become insensitive at Methods This paper reports the development of a sensitive and specific real-time Quantitative Nucleic Acid Sequence Based Amplification (real-time QT-NASBA assays, based on the small-subunit 18S rRNA gene, to identify the four human Plasmodium species. Results The lower detection limit of the assay is 100 – 1000 molecules in vitro RNA for all species, which corresponds to 0.01 – 0.1 parasite per diagnostic sample (i.e. 50 μl of processed blood. The real-time QT-NASBA was further evaluated using 79 clinical samples from malaria patients: i.e. 11 Plasmodium. falciparum, 37 Plasmodium vivax, seven Plasmodium malariae, four Plasmodium ovale and 20 mixed infections. The initial diagnosis of 69 out of the 79 samples was confirmed with the developed real-time QT-NASBA. Re-analysis of seven available original slides resolved five mismatches. Three of those were initially identified as P. malariae mono-infection, but after re-reading the slides P. falciparum was found, confirming the real-time QT-NASBA result. The other two slides were of poor quality not allowing true species identification. The remaining five discordant results could not be explained by microscopy, but may be due to extreme low numbers of parasites present in the samples. In addition, 12 Plasmodium berghei isolates from mice and 20 blood samples from healthy donors did not show any reaction in the assay. Conclusion Real-time QT-NASBA is a very sensitive and specific technique with a detection limit of 0.1 Plasmodium parasite per diagnostic sample (50 μl of blood and can be used for the detection, identification and quantitative measurement of low parasitaemia of Plasmodium species, thus

  10. Using scores of amino acid topological descriptors for quantitative sequence-mobility modeling of peptides based on support vector machine

    Institute of Scientific and Technical Information of China (English)

    LIANG Guizhao; YANG Shanbin; ZHOU Yuan; ZHOU Peng; LI Zhiliang

    2006-01-01

    Scores of amino acid topological descriptors (SATD) derived from principle components analysis of a matrix of 1262 structural variables related to 23 amino acids were employed to express the structure of 125 peptides in different length.Quantitative sequence-mobility modelings (QSMMs)were constructed using partial least square (PLS)and support vector machine (SVM), respectively. As new amino acid scales, SATD including plentiful information related to biological activity were easily manipulated. Better results were obtained compared to those obtained with PLS, which indicated that SVM presented robust stability and excellent predictive ability for electrophoretic mobilities. These results show that there is a wide prospect for the applications of SATD and SVM regression in QSMMs.

  11. Acid-Base Homeostasis.

    Science.gov (United States)

    Hamm, L Lee; Nakhoul, Nazih; Hering-Smith, Kathleen S

    2015-12-07

    Acid-base homeostasis and pH regulation are critical for both normal physiology and cell metabolism and function. The importance of this regulation is evidenced by a variety of physiologic derangements that occur when plasma pH is either high or low. The kidneys have the predominant role in regulating the systemic bicarbonate concentration and hence, the metabolic component of acid-base balance. This function of the kidneys has two components: reabsorption of virtually all of the filtered HCO3(-) and production of new bicarbonate to replace that consumed by normal or pathologic acids. This production or generation of new HCO3(-) is done by net acid excretion. Under normal conditions, approximately one-third to one-half of net acid excretion by the kidneys is in the form of titratable acid. The other one-half to two-thirds is the excretion of ammonium. The capacity to excrete ammonium under conditions of acid loads is quantitatively much greater than the capacity to increase titratable acid. Multiple, often redundant pathways and processes exist to regulate these renal functions. Derangements in acid-base homeostasis, however, are common in clinical medicine and can often be related to the systems involved in acid-base transport in the kidneys.

  12. Gas release-based prescreening combined with reversed-phase HPLC quantitation for efficient selection of high-γ-aminobutyric acid (GABA)-producing lactic acid bacteria.

    Science.gov (United States)

    Wu, Qinglong; Shah, Nagendra P

    2015-02-01

    High γ-aminobutyric acid (GABA)-producing lactobacilli are promising for the manufacture of GABA-rich foods and to synthesize GRAS (generally recognized as safe)-grade GABA. However, common chromatography-based screening is time-consuming and inefficient. In the present study, Korean kimchi was used as a model of lactic acid-based fermented foods, and a gas release-based prescreening of potential GABA producers was developed. The ability to produce GABA by potential GABA producers in de Man, Rogosa, and Sharpe medium supplemented with or without monosodium glutamate was further determined by HPLC. Based on the results, 9 isolates were regarded as high GABA producers, and were further genetically identified as Lactobacillus brevis based on the sequences of 16S rRNA gene. Gas release-based prescreening combined with reversed-phase HPLC confirmation was an efficient and cost-effective method to identify high-GABA-producing LAB, which could be good candidates for probiotics. The GABA that is naturally produced by these high-GABA-producing LAB could be used as a food additive.

  13. A quantitative structure–activity relationship (QSAR) study of peptide drugs based on a new descriptor of amino acids

    OpenAIRE

    Tong Jian-Bo; Chang Jia; Liu Shu-Ling; Bai Min

    2015-01-01

    Quantitative structure-activity relationships (QSAR) approach is used for finding the relationship between molecular structures and the activity of peptide drugs. In this work, stepwise multiple regression, was employed to select optimal subset of descriptors that have significant contribution to the drug activity of 21 oxytocin analogues, 48 bitter tasting threshold, and 58 angiotensin-converting enzyme inhibitors. A new set of descriptor, SVWGM, was used ...

  14. A quantitative structure–activity relationship (QSAR study of peptide drugs based on a new descriptor of amino acids

    Directory of Open Access Journals (Sweden)

    Tong Jian-Bo

    2015-01-01

    Full Text Available Quantitative structure-activity relationships (QSAR approach is used for finding the relationship between molecular structures and the activity of peptide drugs. In this work, stepwise multiple regression, was employed to select optimal subset of descriptors that have significant contribution to the drug activity of 21 oxytocin analogues, 48 bitter tasting threshold, and 58 angiotensin-converting enzyme inhibitors. A new set of descriptor, SVWGM, was used for the prediction of the drug activity of peptide drugs and then were used to build the model by partial least squares method, for it’s estimation stability and generalization ability was strictly analyzed by both internal and external validations, with cross-validation correlation coefficient, correlation coefficient and correlation coefficient of external validation.

  15. Efficiency of peracetic acid in inactivating bacteria, viruses, and spores in water determined with ATP bioluminescence, quantitative PCR, and culture-based methods.

    Science.gov (United States)

    Park, Eunyoung; Lee, Cheonghoon; Bisesi, Michael; Lee, Jiyoung

    2014-03-01

    The disinfection efficiency of peracetic acid (PAA) was investigated on three microbial types using three different methods (filtration-based ATP (adenosine-triphosphate) bioluminescence, quantitative polymerase chain reaction (qPCR), culture-based method). Fecal indicator bacteria (Enterococcus faecium), virus indicator (male-specific (F(+)) coliphages (coliphages)), and protozoa disinfection surrogate (Bacillus subtilis spores (spores)) were tested. The mode of action for spore disinfection was visualized using scanning electron microscopy. The results indicated that PAA concentrations of 5 ppm (contact time: 5 min), 50 ppm (10 min), and 3,000 ppm (5 min) were needed to achieve 3-log reduction of E. faecium, coliphages, and spores, respectively. Scanning electron microscopy observation showed that PAA targets the external layers of spores. The lower reduction rates of tested microbes measured with qPCR suggest that qPCR may overestimate the surviving microbes. Collectively, PAA showed broad disinfection efficiency (susceptibility: E. faecium > coliphages > spores). For E. faecium and spores, ATP bioluminescence was substantially faster (∼5 min) than culture-based method (>24 h) and qPCR (2-3 h). This study suggests PAA as an effective alternative to inactivate broad types of microbial contaminants in water. Together with the use of rapid detection methods, this approach can be useful for urgent situations when timely response is needed for ensuring water quality.

  16. Detection and identification of human Plasmodium species with real-time quantitative nucleic acid sequence-based amplification

    NARCIS (Netherlands)

    P.F. Mens; G.J. Schoone; P.A. Kager; H.D.F.H. Schallig

    2006-01-01

    Background: Decisions concerning malaria treatment depend on species identification causing disease. Microscopy is most frequently used, but at low parasitaemia (< 20 parasites/mu l) the technique becomes less sensitive and time consuming. Rapid diagnostic tests based on Plasmodium antigen detection

  17. Quantitative comparison of ammonia and 3-indoleacetic acid ...

    African Journals Online (AJOL)

    Quantitative comparison of ammonia and 3-indoleacetic acid production in ... method and 3-indoleacetic acid as Salkowski method in halophilic, alkalophilic and ... in research due to their ease of implementation and relatively accurate results.

  18. NanoDrop microvolume quantitation of nucleic acids.

    Science.gov (United States)

    Desjardins, Philippe; Conklin, Deborah

    2010-11-22

    Biomolecular assays are continually being developed that use progressively smaller amounts of material, often precluding the use of conventional cuvette-based instruments for nucleic acid quantitation for those that can perform microvolume quantitation. The NanoDrop microvolume sample retention system (Thermo Scientific NanoDrop Products) functions by combining fiber optic technology and natural surface tension properties to capture and retain minute amounts of sample independent of traditional containment apparatus such as cuvettes or capillaries. Furthermore, the system employs shorter path lengths, which result in a broad range of nucleic acid concentration measurements, essentially eliminating the need to perform dilutions. Reducing the volume of sample required for spectroscopic analysis also facilitates the inclusion of additional quality control steps throughout many molecular workflows, increasing efficiency and ultimately leading to greater confidence in downstream results. The need for high-sensitivity fluorescent analysis of limited mass has also emerged with recent experimental advances. Using the same microvolume sample retention technology, fluorescent measurements may be performed with 2 μL of material, allowing fluorescent assays volume requirements to be significantly reduced. Such microreactions of 10 μL or less are now possible using a dedicated microvolume fluorospectrometer. Two microvolume nucleic acid quantitation protocols will be demonstrated that use integrated sample retention systems as practical alternatives to traditional cuvette-based protocols. First, a direct A260 absorbance method using a microvolume spectrophotometer is described. This is followed by a demonstration of a fluorescence-based method that enables reduced-volume fluorescence reactions with a microvolume fluorospectrometer. These novel techniques enable the assessment of nucleic acid concentrations ranging from 1 pg/ μL to 15,000 ng/ μL with minimal consumption of

  19. qfasar: quantitative fatty acid signature analysis with R

    Science.gov (United States)

    Bromaghin, Jeffrey

    2017-01-01

    Knowledge of predator diets provides essential insights into their ecology, yet diet estimation is challenging and remains an active area of research.Quantitative fatty acid signature analysis (QFASA) is a popular method of estimating diet composition that continues to be investigated and extended. However, software to implement QFASA has only recently become publicly available.I summarize a new R package, qfasar, for diet estimation using QFASA methods. The package also provides functionality to evaluate and potentially improve the performance of a library of prey signature data, compute goodness-of-fit diagnostics, and support simulation-based research. Several procedures in the package have not previously been published.qfasar makes traditional and recently published QFASA diet estimation methods accessible to ecologists for the first time. Use of the package is illustrated with signature data from Chukchi Sea polar bears and potential prey species.

  20. Spectrophotometric quantitation of DNA on blots after ethanol-solubilization of the MTT-formazan from anti-digoxigenin-based detection of nucleic acids.

    Science.gov (United States)

    Colgan, D J

    1993-01-01

    The tetrazolium salt, 3-(4,5-dimethyl-thiazolyl-2)-2,5-diphenyl tetrazolium bromide (MTT) has recently been established as a substitute for Nitro-blue tetrazolium (NBT) in stain mixtures using antibody-conjugated alkaline phosphatase for the location of proteins on Western blots (Heegaard, 1990). Experiments reported here show that MTT is as sensitive as NBT in digoxigenin-labeled probe localization (on nucleic acid blots) utilizing alkaline-phosphatase-labelled, anti-digoxigenin antibodies. Moreover, as the formazan from MTT is soluble in ethanol, it is shown that spectrophotometric quantitation can be used to estimate the amount of target DNA on dot and Southern blots. For dot blotting, pBR328 was used as the probe and pBR322 as target. For Southern blots, human rDNA was used as the probe and total genomic calf DNA as the target. Staining response was linear over at least six twofold DNA dilutions in both types of blot.

  1. Accurate and easy-to-use assessment of contiguous DNA methylation sites based on proportion competitive quantitative-PCR and lateral flow nucleic acid biosensor.

    Science.gov (United States)

    Xu, Wentao; Cheng, Nan; Huang, Kunlun; Lin, Yuehe; Wang, Chenguang; Xu, Yuancong; Zhu, Longjiao; Du, Dan; Luo, Yunbo

    2016-06-15

    Many types of diagnostic technologies have been reported for DNA methylation, but they require a standard curve for quantification or only show moderate accuracy. Moreover, most technologies have difficulty providing information on the level of methylation at specific contiguous multi-sites, not to mention easy-to-use detection to eliminate labor-intensive procedures. We have addressed these limitations and report here a cascade strategy that combines proportion competitive quantitative PCR (PCQ-PCR) and lateral flow nucleic acid biosensor (LFNAB), resulting in accurate and easy-to-use assessment. The P16 gene with specific multi-methylated sites, a well-studied tumor suppressor gene, was used as the target DNA sequence model. First, PCQ-PCR provided amplification products with an accurate proportion of multi-methylated sites following the principle of proportionality, and double-labeled duplex DNA was synthesized. Then, a LFNAB strategy was further employed for amplified signal detection via immune affinity recognition, and the exact level of site-specific methylation could be determined by the relative intensity of the test line and internal reference line. This combination resulted in all recoveries being greater than 94%, which are pretty satisfactory recoveries in DNA methylation assessment. Moreover, the developed cascades show significantly high usability as a simple, sensitive, and low-cost tool. Therefore, as a universal platform for sensing systems for the detection of contiguous multi-sites of DNA methylation without external standards and expensive instrumentation, this PCQ-PCR-LFNAB cascade method shows great promise for the point-of-care diagnosis of cancer risk and therapeutics.

  2. Absolute quantitation of proteins by Acid hydrolysis combined with amino Acid detection by mass spectrometry

    DEFF Research Database (Denmark)

    Mirgorodskaya, Olga A; Körner, Roman; Kozmin, Yuri P;

    2012-01-01

    Amino acid analysis is among the most accurate methods for absolute quantification of proteins and peptides. Here, we combine acid hydrolysis with the addition of isotopically labeled standard amino acids and analysis by mass spectrometry for accurate and sensitive protein quantitation...

  3. Quantitation of glial fibrillary acidic protein in human brain tumours

    DEFF Research Database (Denmark)

    Rasmussen, S; Bock, E; Warecka, K

    1980-01-01

    The glial fibrillary acidic protein (GFA) content of 58 human brain tumours was determined by quantitative immunoelectrophoresis, using monospecific antibody against GFA. Astrocytomas, glioblastomas, oligodendrogliomas, spongioblastomas, ependymomas and medulloblastomas contained relatively high...... amounts of GFA, up to 85 times the concentration in parietal grey substance of normal human brain. GFA was not found in neurinomas, meningiomas, adenomas of the hypophysis, or in a single case of metastasis of adenocarcinoma. Non-glial tumours of craniopharyngioma and haemangioblastoma were infiltrated...

  4. [Quantitative analysis of seven phenolic acids in eight Yinqiao Jiedu serial preparations by quantitative analysis of multi-components with single-marker].

    Science.gov (United States)

    Wang, Jun-jun; Zhang, Li; Guo, Qing; Kou, Jun-ping; Yu, Bo-yang; Gu, Dan-hua

    2015-04-01

    The study aims to develop a unified method to determine seven phenolic acids (neochlorogenic acid, chlorogenic acid, 4-caffeoylquinic acid, caffeic acid, isochlorogenic acid B, isochlorogenic acid A and isochlorogenic acid C) contained in honeysuckle flower that is the monarch drug of all the eight Yinqiao Jiedu serial preparations using quantitative analysis of multi-components by single-marker (QAMS). Firstly, chlorogenic acid was used as a reference to get the average relative correction factors (RCFs) of the other phenolic acids in ratios to the reference; columns and instruments from different companies were used to validate the durability of the achieved RCFs in different levels of standard solutions; and honeysuckle flower extract was used as the reference substance to fix the positions of chromatographic peaks. Secondly, the contents of seven phenolic acids in eight different Yinqiao Jiedu serial preparations samples were calculated based on the RCFs durability. Finally, the quantitative results were compared between QAMS and the external standard (ES) method. The results have showed that the durability of the achieved RCFs is good (RSD during 0.80% - 2.56%), and there are no differences between the quantitative results of QAMS and ES (the relative average deviation quantitative control of honeysuckle flower principally prescribed in Yinqiao Jiedu serial preparations.

  5. Monitoring acidic and basic molecular contamination in leading edge lithography and metrology applications: quantitative comparison of solid state and impinger-based sampling methods

    Science.gov (United States)

    Riddle Vogt, Sarah; Landoni, Cristian

    2010-03-01

    Assessing molecular contamination (MC) at part-per-billion (ppbV) or part-per-trillion volume (pptV) levels in cleanroom air and purge gas lines is essential to protect lithography and metrology tools optics and components. Current lithography and metrology tool manufacturer's specifications require testing of some contaminants down to single digit pptV levels. Ideally this analysis would be performed with an on-line analyzer (capable of providing almost instant results): the best analyzers currently available are only capable of providing 100 pptV detection. Liquid impinger sampling has been the dominant sample collection method for sub ppbV acidic and basic MC analysis. Impinger sampling suffers from some inherent problems that can dramatically reduce the collection efficiency such as analyte solubility and evaporative losses. An innovative solid-state trapping technology has been recently developed by SAES Pure Gas along with the CollectTorr sampling system. NIST traceable gas phase standards have been used to compare the collection efficiency of the traditional impinger technology to that of the solid state trapping method. Results varied greatly for the different acid gases with sulfur dioxide showing comparable collection efficiencies while hydrofluoric acid and hydrochloric acid showed much lower recoveries in the impingers than the solid-state traps. Ammonia collection efficiencies were slightly higher for the solid state traps and were improved in the impingers when an acidified solution was used as the collection media. The use of solid-state traps, besides being much simpler from both the handling and logistical stand point, eliminates the analyte solubility and evaporation problems frequently seen with the impinger sampling.

  6. Quantitative thermodynamic predication of interactions between nucleic acid and non-nucleic acid species using Microsoft excel.

    Science.gov (United States)

    Zou, Jiaqi; Li, Na

    2013-09-01

    Proper design of nucleic acid sequences is crucial for many applications. We have previously established a thermodynamics-based quantitative model to help design aptamer-based nucleic acid probes by predicting equilibrium concentrations of all interacting species. To facilitate customization of this thermodynamic model for different applications, here we present a generic and easy-to-use platform to implement the algorithm of the model with Microsoft(®) Excel formulas and VBA (Visual Basic for Applications) macros. Two Excel spreadsheets have been developed: one for the applications involving only nucleic acid species, the other for the applications involving both nucleic acid and non-nucleic acid species. The spreadsheets take the nucleic acid sequences and the initial concentrations of all species as input, guide the user to retrieve the necessary thermodynamic constants, and finally calculate equilibrium concentrations for all species in various bound and unbound conformations. The validity of both spreadsheets has been verified by comparing the modeling results with the experimental results on nucleic acid sequences reported in the literature. This Excel-based platform described here will allow biomedical researchers to rationalize the sequence design of nucleic acid probes using the thermodynamics-based modeling even without relevant theoretical and computational skills. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  7. Quantitative determination of glycyrrhizinic acid by square-wave

    Directory of Open Access Journals (Sweden)

    Aneta Dimitrovska

    2003-06-01

    Full Text Available Novel adsorptive stripping square-wave voltammetric method as well as a new high-pressure liquid chromatographic method for direct determination of glycyrrhizinic acid in dosage pharmaceutical preparation, used against virus infections, have been developed. Glycyrrhizinic acid is an electrochemically active compound, which undergoes irreversible reduction on a mercury electrode surface in an aqueous medium. Its redox properties were studied thoroughly by means of square-wave voltammetry, as one of the most advanced electroanalytical technique. The voltammetric response depends mainly on the pH of the medium, composition of the supporting electrolyte, as well as the parameters of the excitement signal. It was also observed that the voltammetric properties strongly depend on the accumulation time and potential, revealing significant adsorption of glycyrrhizinic acid onto the mercury electrode surface. Upon this feature, an adsorptive stripping voltammetric method for quantitative determination of glycyrrhizinic acid was developed. A simple, sensitive and precise reversed phase HPLC method with photodiode array UV detection has also been developed, mainly for comparison and conformation of the results obtained with the voltammetric method.

  8. Simulating realistic predator signatures in quantitative fatty acid signature analysis

    Science.gov (United States)

    Bromaghin, Jeffrey F.

    2015-01-01

    Diet estimation is an important field within quantitative ecology, providing critical insights into many aspects of ecology and community dynamics. Quantitative fatty acid signature analysis (QFASA) is a prominent method of diet estimation, particularly for marine mammal and bird species. Investigators using QFASA commonly use computer simulation to evaluate statistical characteristics of diet estimators for the populations they study. Similar computer simulations have been used to explore and compare the performance of different variations of the original QFASA diet estimator. In both cases, computer simulations involve bootstrap sampling prey signature data to construct pseudo-predator signatures with known properties. However, bootstrap sample sizes have been selected arbitrarily and pseudo-predator signatures therefore may not have realistic properties. I develop an algorithm to objectively establish bootstrap sample sizes that generates pseudo-predator signatures with realistic properties, thereby enhancing the utility of computer simulation for assessing QFASA estimator performance. The algorithm also appears to be computationally efficient, resulting in bootstrap sample sizes that are smaller than those commonly used. I illustrate the algorithm with an example using data from Chukchi Sea polar bears (Ursus maritimus) and their marine mammal prey. The concepts underlying the approach may have value in other areas of quantitative ecology in which bootstrap samples are post-processed prior to their use.

  9. Quantitative Determination of Citric and Ascorbic Acid in Powdered Drink Mixes

    Science.gov (United States)

    Sigmann, Samuella B.; Wheeler, Dale E.

    2004-01-01

    A procedure by which the reactions are used to quantitatively determine the amount of total acid, the amount of total ascorbic acid and the amount of citric acid in a given sample of powdered drink mix, are described. A safe, reliable and low-cost quantitative method to analyze consumer product for acid content is provided.

  10. Efficient, validated method for detection of mycobacterial growth in liquid culture media by use of bead beating, magnetic-particle-based nucleic acid isolation, and quantitative PCR.

    Science.gov (United States)

    Plain, Karren M; Waldron, Anna M; Begg, Douglas J; de Silva, Kumudika; Purdie, Auriol C; Whittington, Richard J

    2015-04-01

    Pathogenic mycobacteria are difficult to culture, requiring specialized media and a long incubation time, and have complex and exceedingly robust cell walls. Mycobacterium avium subsp. paratuberculosis (MAP), the causative agent of Johne's disease, a chronic wasting disease of ruminants, is a typical example. Culture of MAP from the feces and intestinal tissues is a commonly used test for confirmation of infection. Liquid medium offers greater sensitivity than solid medium for detection of MAP; however, support for the BD Bactec 460 system commonly used for this purpose has been discontinued. We previously developed a new liquid culture medium, M7H9C, to replace it, with confirmation of growth reliant on PCR. Here, we report an efficient DNA isolation and quantitative PCR methodology for the specific detection and confirmation of MAP growth in liquid culture media containing egg yolk. The analytical sensitivity was at least 10(4)-fold higher than a commonly used method involving ethanol precipitation of DNA and conventional PCR; this may be partly due to the addition of a bead-beating step to manually disrupt the cell wall of the mycobacteria. The limit of detection, determined using pure cultures of two different MAP strains, was 100 to 1,000 MAP organisms/ml. The diagnostic accuracy was confirmed using a panel of cattle fecal (n=54) and sheep fecal and tissue (n=90) culture samples. This technique is directly relevant for diagnostic laboratories that perform MAP cultures but may also be applicable to the detection of other species, including M. avium and M. tuberculosis.

  11. Quantitative measurement of endogenous amino acid absorption in unanaesthetized pigs.

    Science.gov (United States)

    Rerat, A; Vaissade, P; Vaugelade, P

    1988-06-01

    The present experiment was carried out with 11 pigs (mean body weight: 53.9 +/- 1.3 kg) fitted with permanent catheters in the portal vein and carotid artery and with an electromagnetic flow probe around the portal vein. They were each subjected to 2 or 3 trials at 3 to 4-day intervals. During each trial the animals received after a previous fasting of 20 h a given amount of a protein-free diet (200 to 1200 g). The blood was collected either continuously for a quantitative determination of amino nitrogen, reducing sugars, urea and ammonia (number of meals 12, mean intake: 727 +/- 60 g) or discontinuously every 30 min between 0 and 8 h after the meal for amino acid analysis (number of meals 8; mean intake 709 +/- 105 g). A rather constant appearance (2 g/h) of amino acids in the portal blood was observed throughout the postprandial period. The intestinal absorption of each amino acid was however variable and represented between 10 and 50% of the daily requirements of the animal during the measuring period (8 h). Glutamine and to a less extent glutamic acid were exceptions as they were taken up by the gut wall from the arterial blood. There was also a marked synthesis of ornithine and citrulline by the latter. Because of the low blood level of urea, there were no apparent exchanges of urea between the blood and the intestine; in contrast, the ammonia absorption represented about 70% of that observed after ingestion of normal protein diets. Most amino acids are largely taken up by the liver and peripheral tissues, but in the case of alanine the syntheses exceed the uptake.

  12. 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.

  13. [Absolute quantification of carminic acid in cochineal extract by quantitative NMR].

    Science.gov (United States)

    Sugimoto, Naoki; Tada, Atsuko; Suematsu, Takako; Arifuku, Kazunori; Saito, Takeshi; Ihara, Toshihide; Yoshida, Yuuichi; Kubota, Reiji; Tahara, Maiko; Shimizu, Kumiko; Ito, Sumio; Yamazaki, Takeshi; Kawamura, Yoko; Nishimura, Tetsuji

    2010-01-01

    A quantitative NMR (qNMR) method was applied for the determination of carminic acid. Carminic acid is the main component in cochineal dye that is widely used as a natural food colorant. Since several manufacturers only provide reagent-grade carminic acid, there is no reference material of established purity. To improve the reliability of analytical data, we are developing quantitative nuclear magnetic resonance (qNMR), based on the fact that the intensity of a given NMR resonance is directly proportional to the molar amount of that nucleus in the sample. The purities and contents of carminic acid were calculated from the ratio of the signal intensities of an aromatic proton on carminic acid to nine protons of three methyl groups on DSS-d6 used as the internal standard. The concentration of DSS-d6 itself was corrected using potassium hydrogen phthalate, which is a certified reference material (CRM). The purities of the reagents and the contents of carminic acid in cochineal dye products were determined with SI-traceability as 25.3-92.9% and 4.6-30.5% based on the crystalline formula, carminic acid potassium salt trihydrate, which has been confirmed by X-ray analysis. The qNMR method does not require a reference compound, and is rapid and simple, with an overall analysis time of only 10 min. Our approach thus represents an absolute quantitation method with SI-traceability that should be readily applicable to analysis and quality control of any natural product.

  14. In vitro quantitative analysis of Salmonella typhimurium preference for amino acids secreted by human breast tumor

    Science.gov (United States)

    Choi, Eunpyo; Maeng, Bohee; Lee, Jae-hun; Chang, Hyung-kwan; Park, Jungyul

    2016-12-01

    Bacterial therapies have been paid significant attentions by their ability to penetrate deep into the solid tumor tissue and its propensity to naturally accumulate in tumors of living animals. Understanding the actual mechanism for bacteria to target the tumor is therapeutically crucial but is poorly understood. We hypothesized that amino acids released from the specific tumors induced bacteria to those tumors and the experiments for chemotactic response of bacteria toward the cancer secreting amino acids was then performed by using the diffusion based multiple chemical gradient generator constructed by in situ self-assembly of microspheres. The quantitative analysis was carried out by comparison of intensity using green fluorescent protein (GFP) tagged Salmonella typhimurium ( S. typhimurium) in the gradient generator, which showed the clear preference to the released amino acids, especially from breast cancer patients. The understanding chemotaxis toward the cancer secreting amino acids is essential for controlling S. typhimurium targeting in tumors and will allow for the development of bacterial therapies.

  15. Novel bioluminescent quantitative detection of nucleic acid amplification in real-time.

    Directory of Open Access Journals (Sweden)

    Olga A Gandelman

    Full Text Available BACKGROUND: The real-time monitoring of polynucleotide amplification is at the core of most molecular assays. This conventionally relies on fluorescent detection of the amplicon produced, requiring complex and costly hardware, often restricting it to specialised laboratories. PRINCIPAL FINDINGS: Here we report the first real-time, closed-tube luminescent reporter system for nucleic acid amplification technologies (NAATs enabling the progress of amplification to be continuously monitored using simple light measuring equipment. The Bioluminescent Assay in Real-Time (BART continuously reports through bioluminescent output the exponential increase of inorganic pyrophosphate (PPi produced during the isothermal amplification of a specific nucleic acid target. BART relies on the coupled conversion of inorganic pyrophosphate (PPi produced stoichiometrically during nucleic acid synthesis to ATP by the enzyme ATP sulfurylase, and can therefore be coupled to a wide range of isothermal NAATs. During nucleic acid amplification, enzymatic conversion of PPi released during DNA synthesis into ATP is continuously monitored through the bioluminescence generated by thermostable firefly luciferase. The assay shows a unique kinetic signature for nucleic acid amplifications with a readily identifiable light output peak, whose timing is proportional to the concentration of original target nucleic acid. This allows qualitative and quantitative analysis of specific targets, and readily differentiates between negative and positive samples. Since quantitation in BART is based on determination of time-to-peak rather than absolute intensity of light emission, complex or highly sensitive light detectors are not required. CONCLUSIONS: The combined chemistries of the BART reporter and amplification require only a constant temperature maintained by a heating block and are shown to be robust in the analysis of clinical samples. Since monitoring the BART reaction requires only a

  16. An efficient approach to the quantitative analysis of humic acid in water.

    Science.gov (United States)

    Wang, Xue; Li, Bao Qiong; Zhai, Hong Lin; Xiong, Meng Yi; Liu, Ying

    2016-01-01

    Rayleigh and Raman scatterings inevitably appear in fluorescence measurements, which make the quantitative analysis more difficult, especially in the overlap of target signals and scattering signals. Based on the grayscale images of three-dimensional fluorescence spectra, the linear model with two selected Zernike moments was established for the determination of humic acid, and applied to the quantitative analysis of the real sample taken from the Yellow River. The correlation coefficient (R(2)) and leave-one-out cross validation correlation coefficient (R(2)cv) were up to 0.9994 and 0.9987, respectively. The average recoveries were reached 96.28%. Compared with N-way partial least square and alternating trilinear decomposition methods, our approach was immune from the scattering and noise signals owing to its powerful multi-resolution characteristic and the obtained results were more reliable and accurate, which could be applied in food analyses.

  17. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS: DETECTION AND QUANTITATION ISSUES AT LOW CONCENTRATIONS

    Science.gov (United States)

    Methods were developed for the extraction from soil, identification, confirmation and quantitation by LC/MS/MS of trace levels of perfluorinated octanoic acid (PFOA), perfluorinated nonanoic acid (PFNA) and perfluorinated decanoic acid (PFDA). Whereas PFOA, PFNA and PFDA all can...

  18. ANALYSIS OF PERFLUORINATED CARBOXYLIC ACIDS IN SOILS: DETECTION AND QUANTITATION ISSUES AT LOW CONCENTRATIONS

    Science.gov (United States)

    Methods were developed for the extraction from soil, identification, confirmation and quantitation by LC/MS/MS of trace levels of perfluorinated octanoic acid (PFOA), perfluorinated nonanoic acid (PFNA) and perfluorinated decanoic acid (PFDA). Whereas PFOA, PFNA and PFDA all can...

  19. Identification and Quantitative Analysis of Acetaminophen, Acetylsalicylic Acid, and Caffeine in Commercial Analgesic Tablets by LC-MS

    Science.gov (United States)

    Fenk, Christopher J.; Hickman, Nicole M.; Fincke, Melissa A.; Motry, Douglas H.; Lavine, Barry

    2010-01-01

    An undergraduate LC-MS experiment is described for the identification and quantitative determination of acetaminophen, acetylsalicylic acid, and caffeine in commercial analgesic tablets. This inquiry-based experimental procedure requires minimal sample preparation and provides good analytical results. Students are provided sufficient background…

  20. Identification and Quantitative Analysis of Acetaminophen, Acetylsalicylic Acid, and Caffeine in Commercial Analgesic Tablets by LC-MS

    Science.gov (United States)

    Fenk, Christopher J.; Hickman, Nicole M.; Fincke, Melissa A.; Motry, Douglas H.; Lavine, Barry

    2010-01-01

    An undergraduate LC-MS experiment is described for the identification and quantitative determination of acetaminophen, acetylsalicylic acid, and caffeine in commercial analgesic tablets. This inquiry-based experimental procedure requires minimal sample preparation and provides good analytical results. Students are provided sufficient background…

  1. 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.

  2. Quantitative proteomics by amino acid labeling in C. elegans

    DEFF Research Database (Denmark)

    Fredens, Julius; Engholm-Keller, Kasper; Giessing, Anders;

    2011-01-01

    We demonstrate labeling of Caenorhabditis elegans with heavy isotope-labeled lysine by feeding them with heavy isotope-labeled Escherichia coli. Using heavy isotope-labeled worms and quantitative proteomics methods, we identified several proteins that are regulated in response to loss or RNAi-med......-mediated knockdown of the nuclear hormone receptor 49 in C. elegans. The combined use of quantitative proteomics and selective gene knockdown is a powerful tool for C. elegans biology.......We demonstrate labeling of Caenorhabditis elegans with heavy isotope-labeled lysine by feeding them with heavy isotope-labeled Escherichia coli. Using heavy isotope-labeled worms and quantitative proteomics methods, we identified several proteins that are regulated in response to loss or RNAi...

  3. Quantitative Modeling of Acid Wormholing in Carbonates- What Are the Gaps to Bridge

    KAUST Repository

    Qiu, Xiangdong

    2013-01-01

    Carbonate matrix acidization extends a well\\'s effective drainage radius by dissolving rock and forming conductive channels (wormholes) from the wellbore. Wormholing is a dynamic process that involves balance between the acid injection rate and reaction rate. Generally, injection rate is well defined where injection profiles can be controlled, whereas the reaction rate can be difficult to obtain due to its complex dependency on interstitial velocity, fluid composition, rock surface properties etc. Conventional wormhole propagation models largely ignore the impact of reaction products. When implemented in a job design, the significant errors can result in treatment fluid schedule, rate, and volume. A more accurate method to simulate carbonate matrix acid treatments would accomodate the effect of reaction products on reaction kinetics. It is the purpose of this work to properly account for these effects. This is an important step in achieving quantitative predictability of wormhole penetration during an acidzing treatment. This paper describes the laboratory procedures taken to obtain the reaction-product impacted kinetics at downhole conditions using a rotating disk apparatus, and how this new set of kinetics data was implemented in a 3D wormholing model to predict wormhole morphology and penetration velocity. The model explains some of the differences in wormhole morphology observed in limestone core flow experiments where injection pressure impacts the mass transfer of hydrogen ions to the rock surface. The model uses a CT scan rendered porosity field to capture the finer details of the rock fabric and then simulates the fluid flow through the rock coupled with reactions. Such a validated model can serve as a base to scale up to near wellbore reservoir and 3D radial flow geometry allowing a more quantitative acid treatment design.

  4. Molten fatty acid based microemulsions.

    Science.gov (United States)

    Noirjean, Cecile; Testard, Fabienne; Dejugnat, Christophe; Jestin, Jacques; Carriere, David

    2016-06-21

    We show that ternary mixtures of water (polar phase), myristic acid (MA, apolar phase) and cetyltrimethylammonium bromide (CTAB, cationic surfactant) studied above the melting point of myristic acid allow the preparation of microemulsions without adding a salt or a co-surfactant. The combination of SANS, SAXS/WAXS, DSC, and phase diagram determination allows a complete characterization of the structures and interactions between components in the molten fatty acid based microemulsions. For the different structures characterized (microemulsion, lamellar or hexagonal phases), a similar thermal behaviour is observed for all ternary MA/CTAB/water monophasic samples and for binary MA/CTAB mixtures without water: crystalline myristic acid melts at 52 °C, and a thermal transition at 70 °C is assigned to the breaking of hydrogen bounds inside the mixed myristic acid/CTAB complex (being the surfactant film in the ternary system). Water determines the film curvature, hence the structures observed at high temperature, but does not influence the thermal behaviour of the ternary system. Myristic acid is partitioned in two "species" that behave independently: pure myristic acid and myristic acid associated with CTAB to form an equimolar complex that plays the role of the surfactant film. We therefore show that myristic acid plays the role of a solvent (oil) and a co-surfactant allowing the fine tuning of the structure of oil and water mixtures. This solvosurfactant behaviour of long chain fatty acid opens the way for new formulations with a complex structure without the addition of any extra compound.

  5. Quantitative gas chromatographic determination of perfluorooctanoic acid as the benzyl ester in plasma and urine

    Energy Technology Data Exchange (ETDEWEB)

    Ylinen, M.; Hanhijaervi, H.; Peura, P.; Raemoe, O.

    1985-11-01

    A method is presented for the quantitative determination of perfluorooctanoic acid in plasma and urine of dogs. The acid was esterified by an extractive alkylation method using tetrabutylammonium ion as the counter ion and benzyl bromide as the alkylating agent. Quantitation was made by gas chromatography. Typical values for precision obtained in the determination of 5 ..mu..g/ml of perfluorooctanoic acid in plasma and urine were 3.3% (S.D. N = 6) and 3.0% (S.D. N = 6), respectively. The limit of detection was 1 ng (2.4 pmol).

  6. New insights into the mechanisms of acetic acid resistance in Acetobacter pasteurianus using iTRAQ-dependent quantitative proteomic analysis.

    Science.gov (United States)

    Xia, Kai; Zang, Ning; Zhang, Junmei; Zhang, Hong; Li, Yudong; Liu, Ye; Feng, Wei; Liang, Xinle

    2016-12-05

    Acetobacter pasteurianus is the main starter in rice vinegar manufacturing due to its remarkable abilities to resist and produce acetic acid. Although several mechanisms of acetic acid resistance have been proposed and only a few effector proteins have been identified, a comprehensive depiction of the biological processes involved in acetic acid resistance is needed. In this study, iTRAQ-based quantitative proteomic analysis was adopted to investigate the whole proteome of different acidic titers (3.6, 7.1 and 9.3%, w/v) of Acetobacter pasteurianus Ab3 during the vinegar fermentation process. Consequently, 1386 proteins, including 318 differentially expressed proteins (pacetic acid stress, where >150 proteins were differentially expressed. Specifically, proteins involved in amino acid metabolic processes and fatty acid biosynthesis were differentially expressed, which may contribute to the acetic acid resistance of Acetobacter. Transcription factors, two component systems and toxin-antitoxin systems were implicated in the modulatory network at multiple levels. In addition, the identification of proteins involved in redox homeostasis, protein metabolism, and the cell envelope suggested that the whole cellular system is mobilized in response to acid stress. These findings provide a differential proteomic profile of acetic acid resistance in Acetobacter pasteurianus and have potential application to highly acidic rice vinegar manufacturing. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Distance measures and optimization spaces in quantitative fatty acid signature analysis

    Science.gov (United States)

    Bromaghin, Jeffrey F.; Rode, Karyn D.; Budge, Suzanne M.; Thiemann, Gregory W.

    2015-01-01

    Quantitative fatty acid signature analysis has become an important method of diet estimation in ecology, especially marine ecology. Controlled feeding trials to validate the method and estimate the calibration coefficients necessary to account for differential metabolism of individual fatty acids have been conducted with several species from diverse taxa. However, research into potential refinements of the estimation method has been limited. We compared the performance of the original method of estimating diet composition with that of five variants based on different combinations of distance measures and calibration-coefficient transformations between prey and predator fatty acid signature spaces. Fatty acid signatures of pseudopredators were constructed using known diet mixtures of two prey data sets previously used to estimate the diets of polar bears Ursus maritimus and gray seals Halichoerus grypus, and their diets were then estimated using all six variants. In addition, previously published diets of Chukchi Sea polar bears were re-estimated using all six methods. Our findings reveal that the selection of an estimation method can meaningfully influence estimates of diet composition. Among the pseudopredator results, which allowed evaluation of bias and precision, differences in estimator performance were rarely large, and no one estimator was universally preferred, although estimators based on the Aitchison distance measure tended to have modestly superior properties compared to estimators based on the Kullback-Leibler distance measure. However, greater differences were observed among estimated polar bear diets, most likely due to differential estimator sensitivity to assumption violations. Our results, particularly the polar bear example, suggest that additional research into estimator performance and model diagnostics is warranted.

  8. A quantitative measure of chirality inside nucleic acid databank.

    Science.gov (United States)

    Pietropaolo, Adriana; Parrinello, Michele

    2011-08-01

    We show the capability of a chirality index (Pietropaolo et al., Proteins 2008;70:667-677) to investigate nucleic acid structures because of its high sensitivity to helical conformations. By analyzing selected structures of DNA and RNA, we have found that sequences rich in cytosine and guanine have a tendency to left-handed chirality, in contrast to regions rich in adenine or thymine which show strong negative, right-handed, chirality values. We also analyze RNA structures, where specific loops and hairpin motifs are characterized by a well-defined chirality value. We find that in nucleosome the chirality is exalted, whereas in ribosome it is reduced. Our results illustrate the sensitivity of this descriptor for nucleic acid conformations.

  9. Quantitative detection of single amino acid polyrnorphisms by targeted proteornics

    Institute of Scientific and Technical Information of China (English)

    Zhi-Duan Su; Jia-Rui Wu; Liang Sun; Dan-Xia Yu; Rong-Xia Li; Huai-Xing Li; Zhi-Jie Yu; Quan-Hu Sheng; Xu Lin; RongZeng

    2011-01-01

    Single-nucleotide polymorphisms (SNPs) are recognized as one kind of major genetic variants in population scale. However, polymorphisms at the proteome level in population scale remain elusive. In the present study, we named amino acid variances derived from SNPs within coding regions as single amino acid polymorphisms (SAPs) at the proteome level, and developed a pipeline of non-targeted and targeted proteomics to identify and quantify SAP peptides in human plasma. The absolute concentrations of three selected SAP-peptide pairs among 290 Asian individuals were measured by selected reaction monitoring (SRM) approach, and their associations with both obesity and diabetes were further analyzed. This work revealed that heterozygotes and homozygotes with various SAPs in a population could have different associations with particular traits. In addition, the SRM approach allows us for the first time to separately measure the absolute concentration of each SAP peptide in the heterozygotes, which also shows different associations with particular traits.%Single-nucleotide polymorphisms (SNPs) are recognized as one kind of major genetic variants in population scale.However,polymorphisms at the proteome level in population scale remain elusive.In the present study,we named amino acid variances derived from SNPs within coding regions as single amino acid polymorphisms (SAPs) at the proteome level,and developed a pipeline of non-targeted and targeted proteomics to identify and quantify SAP peptides in human plasma.The absolute concentrations of three selected SAP-peptide pairs among 290 Asian individuals were measured by selected reaction monitoring (SRM) approach,and their associations with both obesity and diabetes were further analyzed.This work revealed that heterozygotes and homozygotes with various SAPs in a population could have different associations with particular traits.In addition,the SRM approach allows us for the first time to separately measure the absolute

  10. Classification of cassava genotypes based on qualitative and quantitative data.

    Science.gov (United States)

    Oliveira, E J; Oliveira Filho, O S; Santos, V S

    2015-02-02

    We evaluated the genetic variation of cassava accessions based on qualitative (binomial and multicategorical) and quantitative traits (continuous). We characterized 95 accessions obtained from the Cassava Germplasm Bank of Embrapa Mandioca e Fruticultura; we evaluated these accessions for 13 continuous, 10 binary, and 25 multicategorical traits. First, we analyzed the accessions based only on quantitative traits; next, we conducted joint analysis (qualitative and quantitative traits) based on the Ward-MLM method, which performs clustering in two stages. According to the pseudo-F, pseudo-t2, and maximum likelihood criteria, we identified five and four groups based on quantitative trait and joint analysis, respectively. The smaller number of groups identified based on joint analysis may be related to the nature of the data. On the other hand, quantitative data are more subject to environmental effects in the phenotype expression; this results in the absence of genetic differences, thereby contributing to greater differentiation among accessions. For most of the accessions, the maximum probability of classification was >0.90, independent of the trait analyzed, indicating a good fit of the clustering method. Differences in clustering according to the type of data implied that analysis of quantitative and qualitative traits in cassava germplasm might explore different genomic regions. On the other hand, when joint analysis was used, the means and ranges of genetic distances were high, indicating that the Ward-MLM method is very useful for clustering genotypes when there are several phenotypic traits, such as in the case of genetic resources and breeding programs.

  11. 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.

  12. Quality control for quantitative PCR based on amplification compatibility test.

    Science.gov (United States)

    Tichopad, Ales; Bar, Tzachi; Pecen, Ladislav; Kitchen, Robert R; Kubista, Mikael; Pfaffl, Michael W

    2010-04-01

    Quantitative qPCR is a routinely used method for the accurate quantification of nucleic acids. Yet it may generate erroneous results if the amplification process is obscured by inhibition or generation of aberrant side-products such as primer dimers. Several methods have been established to control for pre-processing performance that rely on the introduction of a co-amplified reference sequence, however there is currently no method to allow for reliable control of the amplification process without directly modifying the sample mix. Herein we present a statistical approach based on multivariate analysis of the amplification response data generated in real-time. The amplification trajectory in its most resolved and dynamic phase is fitted with a suitable model. Two parameters of this model, related to amplification efficiency, are then used for calculation of the Z-score statistics. Each studied sample is compared to a predefined reference set of reactions, typically calibration reactions. A probabilistic decision for each individual Z-score is then used to identify the majority of inhibited reactions in our experiments. We compare this approach to univariate methods using only the sample specific amplification efficiency as reporter of the compatibility. We demonstrate improved identification performance using the multivariate approach compared to the univariate approach. Finally we stress that the performance of the amplification compatibility test as a quality control procedure depends on the quality of the reference set.

  13. Nucleic acid based logical systems.

    Science.gov (United States)

    Han, Da; Kang, Huaizhi; Zhang, Tao; Wu, Cuichen; Zhou, Cuisong; You, Mingxu; Chen, Zhuo; Zhang, Xiaobing; Tan, Weihong

    2014-05-12

    Researchers increasingly visualize a significant role for artificial biochemical logical systems in biological engineering, much like digital logic circuits in electrical engineering. Those logical systems could be utilized as a type of servomechanism to control nanodevices in vitro, monitor chemical reactions in situ, or regulate gene expression in vivo. Nucleic acids (NA), as carriers of genetic information with well-regulated and predictable structures, are promising materials for the design and engineering of biochemical circuits. A number of logical devices based on nucleic acids (NA) have been designed to handle various processes for technological or biotechnological purposes. This article focuses on the most recent and important developments in NA-based logical devices and their evolution from in vitro, through cellular, even towards in vivo biological applications.

  14. Oxidized fatty acid analysis by charge-switch derivatization, selected reaction monitoring, and accurate mass quantitation.

    Science.gov (United States)

    Liu, Xinping; Moon, Sung Ho; Mancuso, David J; Jenkins, Christopher M; Guan, Shaoping; Sims, Harold F; Gross, Richard W

    2013-11-01

    A highly sensitive, specific, and robust method for the analysis of oxidized metabolites of linoleic acid (LA), arachidonic acid (AA), and docosahexaenoic acid (DHA) was developed using charge-switch derivatization, liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI MS/MS) with selected reaction monitoring (SRM) and quantitation by high mass accuracy analysis of product ions, thereby minimizing interferences from contaminating ions. Charge-switch derivatization of LA, AA, and DHA metabolites with N-(4-aminomethylphenyl)-pyridinium resulted in a 10- to 30-fold increase in ionization efficiency. Improved quantitation was accompanied by decreased false positive interferences through accurate mass measurements of diagnostic product ions during SRM transitions by ratiometric comparisons with stable isotope internal standards. The limits of quantitation were between 0.05 and 6.0pg, with a dynamic range of 3 to 4 orders of magnitude (correlation coefficient r(2)>0.99). This approach was used to quantitate the levels of representative fatty acid metabolites from wild-type (WT) and iPLA2γ(-/-) mouse liver identifying the role of iPLA2γ in hepatic lipid second messenger production. Collectively, these results demonstrate the utility of high mass accuracy product ion analysis in conjunction with charge-switch derivatization for the highly specific quantitation of diminutive amounts of LA, AA, and DHA metabolites in biologic systems. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Quantitative Structure-property Relationship Studies on Amino Acid Conjugates of Jasmonic Acid as Defense Signaling Molecules

    Institute of Scientific and Technical Information of China (English)

    Zu-Guang Li; Ke-Xian Chen; Hai-Ying Xie; Jian-Rong Gao

    2009-01-01

    Jasmonates and related compounds, including amino acid conjugates of jasmonic acid, have regulatory functions in the signaling pathway for plant developmental processes and responses to the complex equilibrium of biotic and abiotic stress.But the molecular details of the signaling mechanism are still poorly understood. Statistically significant quantitative structure-property relationship models (r2 > 0.990) constructed by genetic function approximation and molecular field analysis were generated for the purpose of deriving structural requirements for lipophilicity of amino acid conjugates of jasmonic acid. The best models derived in the present study provide some valuable academic information in terms of the 213D-descriptors influencing the lipophilicity, which may contribute to further understanding the mechanism of exogenous application of jasmonates in their signaling pathway and designing novel analogs ofjasmonic acid as ecological pesticides.

  16. New Descriptors of Amino Acids and Its Applications to Peptide Quantitative Structure-activity Relationship

    Institute of Scientific and Technical Information of China (English)

    SHU Mao; HUO Dan-Qun; MEI Hua; LIANG Gui-Zhao; ZHANG Mei; LI Zhi-Liang

    2008-01-01

    A new set of descriptors, HSEHPCSV (component score vector of hydrophobic, steric, and electronic properties together with hydrogen bonding contributions), were derived from principal component analyses of 95 physicochemical variables of 20 natural amino acids separately according to different kinds of properties described, namely, hydrophobic, steric, and electronic properties as well as hydrogen bonding contributions. HSEHPCSV scales were then employed to express structures of angiotensin-converting enzyme inhibitors, bitter tasting thresholds and bactericidal 18 peptide, and to construct QSAR models based on partial least square (PLS). The results obtained are as follows: the multiple correlation coefficient (R2cum) of 0.846, 0.917 and 0.993, leave-one-out cross validated Q2cum of 0.835, 0.865 and 0.899, and root-mean-square error for estimated error (RMSEE) of 0.396, 0.187and 0.22, respectively. Satisfactory results showed that, as new amino acid scales, data of HSEHPCSV may be a useful structural expression methodology for the studies on peptide QSAR (quantitative structure-activity relationship) due to many advantages such as plentiful structural information, definite physical and chemical meaning and easy interpretation.

  17. Quantitative analysis of cyclic dimer fatty acid content in the dimerization product by proton NMR spectroscopy.

    Science.gov (United States)

    Park, Kyun Joo; Kim, Minyoung; Seok, Seunghwan; Kim, Young-Wun; Kim, Do Hyun

    2015-01-01

    In this work, (1)H NMR is utilized for the quantitative analysis of a specific cyclic dimer fatty acid in a dimer acid mixture using the pseudo-standard material of mesitylene on the basis of its structural similarity. Mesitylene and cyclic dimer acid levels were determined using the signal of the proton on the cyclic ring (δ=6.8) referenced to the signal of maleic acid (δ=6.2). The content of the cyclic dimer fatty acid was successfully determined through the standard curve of mesitylene and the reported equation. Using the linearity of the mesitylene curve, the cyclic dimer fatty acid in the oil mixture was quantified. The results suggest that the proposed method can be used to quantify cyclic compounds in mixtures to optimize the dimerization process.

  18. A robust GC-MS method for the quantitation of fatty acids in biological systems.

    Science.gov (United States)

    Jayasinghe, Nirupama Samanmalie; Dias, Daniel Anthony

    2013-01-01

    Fatty acids (FAs) are involved in a wide range of functions in biological systems. It is important to measure the exact amount of fatty acids in biological matrices in order to determine the level of fatty acids and understand the role they play. The ability to quantify fatty acids in various systems, especially plant species and microbes has recently paved the way to the mass production of pharmaceuticals and energy substitutes including biodiesel. This chapter describes an efficient method to quantify the total fatty acids (TFAs) in biological systems using gas chromatography-mass spectrometry (GC-MS) and a commercially available standard mix of fatty acid methyl esters (FAMEs) using a step-by-step methodology to setup a quantitation method using the Agilent Chemstation software.

  19. Monitoring lactic acid production during milk fermentation by in situ quantitative proton nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Bouteille, R; Gaudet, M; Lecanu, B; This, H

    2013-04-01

    When fermenting milk, lactic bacteria convert part of α- and β-lactoses into d- and l- lactic acids, causing a pH decrease responsible for casein coagulation. Lactic acid monitoring during fermentation is essential for the control of dairy gel textural and organoleptic properties, and is a way to evaluate strain efficiency. Currently, titrations are used to follow the quantity of acids formed during jellification of milk but they are not specific to lactic acid. An analytical method without the use of any reagent was investigated to quantify lactic acid during milk fermentation: in situ quantitative proton nuclear magnetic resonance spectroscopy. Two methods using in situ quantitative proton nuclear magnetic resonance spectroscopy were compared: (1) d- and l-lactic acids content determination, using the resonance of their methyl protons, showing an increase from 2.06 ± 0.02 to 8.16 ± 0.74 g/L during 240 min of fermentation; and (2) the determination of the α- and β-lactoses content, decreasing from 42.68 ± 0.02 to 30.76 ± 1.75 g/L for the same fermentation duration. The ratio between the molar concentrations of produced lactic acids and consumed lactoses enabled cross-validation, as the value (2.02 ± 0.18) is consistent with lactic acid bacteria metabolism.

  20. QUANTITATIVE DETERMINATION OF SIALIC ACID IN INDIAN MILK AND MILK PRODUCTS

    OpenAIRE

    D.Karunanithi; V.M.Biju; A.Radhakrishna

    2013-01-01

    Background: Sialic acids are acidic sugars with a 9-carbon backbone, expressed as terminal residue on mammalian glycoconjugates. Sialic acid was found in two forms as N-acetylneuraminic acid (Neu5Ac) and N-Glycolylneuraminic acid (Neu5Gc) in meat and milk products. Neu5Ac is important for the brain and neuro development while Neu5Gc is suspected as human carcinogen. There is no data reported on sialic acid content in Indian milk and milk based products. Objective: To determine sialic acid (Ne...

  1. 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…

  2. 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…

  3. Quantitative analysis of 17 amino acids in tobacco leaves using an amino acid analyzer and chemometric resolution.

    Science.gov (United States)

    Zeng, Yihang; Cai, Wensheng; Shao, Xueguang

    2015-06-01

    A method was developed for quantifying 17 amino acids in tobacco leaves by using an A300 amino acid analyzer and chemometric resolution. In the method, amino acids were eluted by the buffer solution on an ion-exchange column. After reacting with ninhydrin, the derivatives of amino acids were detected by ultraviolet detection. Most amino acids are separated by the elution program. However, five peaks of the derivatives are still overlapping. A non-negative immune algorithm was employed to extract the profiles of the derivatives from the overlapping signals, and then peak areas were adopted for quantitative analysis of the amino acids. The method was validated by the determination of amino acids in tobacco leaves. The relative standard deviations (n = 5) are all less than 2.54% and the recoveries of the spiked samples are in a range of 94.62-108.21%. The feasibility of the method was proved by analyzing the 17 amino acids in 30 tobacco leaf samples.

  4. [Reconstituting evaluation methods based on both qualitative and quantitative paradigms].

    Science.gov (United States)

    Miyata, Hiroaki; Okubo, Suguru; Yoshie, Satoru; Kai, Ichiro

    2011-01-01

    Debate about the relationship between quantitative and qualitative paradigms is often muddled and confusing and the clutter of terms and arguments has resulted in the concepts becoming obscure and unrecognizable. In this study we conducted content analysis regarding evaluation methods of qualitative healthcare research. We extracted descriptions on four types of evaluation paradigm (validity/credibility, reliability/credibility, objectivity/confirmability, and generalizability/transferability), and classified them into subcategories. In quantitative research, there has been many evaluation methods based on qualitative paradigms, and vice versa. Thus, it might not be useful to consider evaluation methods of qualitative paradigm are isolated from those of quantitative methods. Choosing practical evaluation methods based on the situation and prior conditions of each study is an important approach for researchers.

  5. Absolute quantification of dehydroacetic acid in processed foods using quantitative ¹H NMR.

    Science.gov (United States)

    Ohtsuki, Takashi; Sato, Kyoko; Furusho, Noriko; Kubota, Hiroki; Sugimoto, Naoki; Akiyama, Hiroshi

    2013-11-15

    An absolute quantification method for the determination of dehydroacetic acid in processed foods using quantitative (1)H NMR was developed and validated. The level of dehydroacetic acid was determined using the proton signals of dehydroacetic acid referenced to 1,4-bis (trimethylsilyl) benzene-d4 after simple solvent extraction from processed foods. All the recoveries from three processed foods spiked at two different concentrations were larger than 85%. The proposed method also proved to be precise, with inter-day precision and excellent linearity. The limit of quantification was confirmed as 0.13g/kg in processed foods, which is sufficiently low for the purposes of monitoring dehydroacetic acid. Furthermore, the method is rapid and easy to apply, and provides International System of Units traceability without the need for authentic analyte reference materials. Therefore, the proposed method is a useful and practical tool for determining the level of dehydroacetic acid in processed foods.

  6. Quantitative data analysis methods for bead-based DNA hybridization assays using generic flow cytometry platforms.

    Science.gov (United States)

    Corrie, S R; Lawrie, G A; Battersby, B J; Ford, K; Rühmann, A; Koehler, K; Sabath, D E; Trau, M

    2008-05-01

    Bead-based assays are in demand for rapid genomic and proteomic assays for both research and clinical purposes. Standard quantitative procedures addressing raw data quality and analysis are required to ensure the data are consistent and reproducible across laboratories independent of flow platform. Quantitative procedures have been introduced spanning raw histogram analysis through to absolute target quantitation. These included models developed to estimate the absolute number of sample molecules bound per bead (Langmuir isotherm), relative quantitative comparisons (two-sided t-tests), and statistical analyses investigating the quality of raw fluorescence data. The absolute target quantitation method revealed a concentration range (below probe saturation) of Cy5-labeled synthetic cytokeratin 19 (K19) RNA of c.a. 1 x 10(4) to 500 x 10(4) molecules/bead, with a binding constant of c.a. 1.6 nM. Raw hybridization frequency histograms were observed to be highly reproducible across 10 triplex assay replicates and only three assay replicates were required to distinguish overlapping peaks representing small sequence mismatches. This study provides a quantitative scheme for determining the absolute target concentration in nucleic acid hybridization reactions and the equilibrium binding constants for individual probe/target pairs. It is envisaged that such studies will form the basis of standard analytical procedures for bead-based cytometry assays to ensure reproducibility in inter- and intra-platform comparisons of data between laboratories. (c) 2008 International Society for Advancement of Cytometry.

  7. Statistical design of quantitative mass spectrometry-based proteomic experiments.

    Science.gov (United States)

    Oberg, Ann L; Vitek, Olga

    2009-05-01

    We review the fundamental principles of statistical experimental design, and their application to quantitative mass spectrometry-based proteomics. We focus on class comparison using Analysis of Variance (ANOVA), and discuss how randomization, replication and blocking help avoid systematic biases due to the experimental procedure, and help optimize our ability to detect true quantitative changes between groups. We also discuss the issues of pooling multiple biological specimens for a single mass analysis, and calculation of the number of replicates in a future study. When applicable, we emphasize the parallels between designing quantitative proteomic experiments and experiments with gene expression microarrays, and give examples from that area of research. We illustrate the discussion using theoretical considerations, and using real-data examples of profiling of disease.

  8. Quantitative mapping by remote sensing of an ocean acid-waste dump

    Science.gov (United States)

    Ohlhorst, C. W.

    1978-01-01

    Results from quantitative analysis show that airplane remotely sensed spectral data can be used to quantify and map an acid-waste dump in terms of its particulate iron concentration. These same data, however, could not be used to map the dump in terms of total suspended solids, organic suspended solids, or inorganic suspended solids concentrations. A single-variable equation using the ratio of band 2 (440 to 490 nm) radiance to band 4 (540 to 580 nm) radiance was used to quantify the iron concentration in the acid-waste dump. The acid waste that was mapped varied in age from freshly dumped to 31/2 hr. Particulate iron concentrations in the acid waste were estimated to range up to 1.1 mg/l at a depth of 0.46 m. A classification technique was developed to identify pixels in the data set affected by sun glitter.

  9. Enantiomer labelling, a method for the quantitative analysis of amino acids.

    Science.gov (United States)

    Frank, H; Nicholson, G J; Bayer, E

    1978-12-21

    Enantiomer labelling a method for the quntitative analysis of optically active natural compounds by gas chromatography, involves the use of the unnatural enantiomer as an internal standard. With Chirasil-Val, a chiral stationary phase that is thermally stable up to up to 240 degrees, the enantiomers of amino acids and a variety of other compounds can be separated and quantitated. Incomplete recovery from the sample, incomplete derivatization, hydrolysis and thermal decomposition of the derivative and shifting response factors can be compensated for by adding the unnatural enantiomer. The accuracy of amino acid analysis by enantiomer labelling is equal or superior to that of hitherto known methods. The procedure affords a complete analysis of peptides with respect to both amino acid composition and the optical purity of each amino acid.

  10. Simultaneous measurement and quantitation of 4-hydroxyphenylacetic acid and dopamine with fast-scan cyclic voltammetry.

    Science.gov (United States)

    Shin, Mimi; Kaplan, Sam V; Raider, Kayla D; Johnson, Michael A

    2015-05-07

    Caged compounds have been used extensively to investigate neuronal function in a variety of preparations, including cell culture, ex vivo tissue samples, and in vivo. As a first step toward electrochemically measuring the extent of caged compound photoactivation while also measuring the release of the catecholamine neurotransmitter, dopamine, fast-scan cyclic voltammetry at carbon-fiber microelectrodes (FSCV) was used to electrochemically characterize 4-hydroxyphenylacetic acid (4HPAA) in the absence and presence of dopamine. 4HPAA is a by-product formed during the process of photoactivation of p-hydroxyphenacyl-based caged compounds, such as p-hydroxyphenylglutamate (pHP-Glu). Our data suggest that the oxidation of 4HPAA occurs through the formation of a conjugated species. Moreover, we found that a triangular waveform of -0.4 V to +1.3 V to -0.4 V at 600 V s(-1), repeated every 100 ms, provided an oxidation current of 4HPAA that was enhanced with a limit of detection of 100 nM, while also allowing the detection and quantitation of dopamine within the same scan. Along with quantifying 4HPAA in biological preparations, the results from this work will allow the electrochemical measurement of photoactivation reactions that generate 4HPAA as a by-product as well as provide a framework for measuring the photorelease of electroactive by-products from caged compounds that incorporate other chromophores.

  11. Synthesis and quantitative structure-property relationships of side chain-modified hyodeoxycholic acid derivatives.

    Science.gov (United States)

    Sabbatini, Paola; Filipponi, Paolo; Sardella, Roccaldo; Natalini, Benedetto; Nuti, Roberto; Macchiarulo, Antonio; Pellicciari, Roberto; Gioiello, Antimo

    2013-08-30

    Bile acids have emerged as versatile signalling compounds of a complex network of nuclear and membrane receptors regulating various endocrine and paracrine functions. The elucidation of the interconnection between the biological pathways under the bile acid control and manifestations of hepatic and metabolic diseases have extended the scope of this class of steroids for in vivo investigations. In this framework, the design and synthesis of novel biliary derivatives able to modulate a specific receptor requires a deep understanding of both structure-activity and structure-property relationships of bile acids. In this paper, we report the preparation and the critical micellization concentration evaluation of a series of hyodeoxycholic acid derivatives characterized by a diverse side chain length and by the presence of a methyl group at the alpha position with respect to the terminal carboxylic acid moiety. The data collected are instrumental to extend on a quantitative basis, the knowledge of the current structure-property relationships of bile acids and will be fruitful, in combination with models of receptor activity, to design and prioritize the synthesis of novel pharmacokinetically suitable ligands useful in the validation of bile acid-responsive receptors as therapeutic targets.

  12. Synthesis and Quantitative Structure-Property Relationships of Side Chain-Modified Hyodeoxycholic Acid Derivatives

    Directory of Open Access Journals (Sweden)

    Antimo Gioiello

    2013-08-01

    Full Text Available Bile acids have emerged as versatile signalling compounds of a complex network of nuclear and membrane receptors regulating various endocrine and paracrine functions. The elucidation of the interconnection between the biological pathways under the bile acid control and manifestations of hepatic and metabolic diseases have extended the scope of this class of steroids for in vivo investigations. In this framework, the design and synthesis of novel biliary derivatives able to modulate a specific receptor requires a deep understanding of both structure-activity and structure-property relationships of bile acids. In this paper, we report the preparation and the critical micellization concentration evaluation of a series of hyodeoxycholic acid derivatives characterized by a diverse side chain length and by the presence of a methyl group at the alpha position with respect to the terminal carboxylic acid moiety. The data collected are instrumental to extend on a quantitative basis, the knowledge of the current structure-property relationships of bile acids and will be fruitful, in combination with models of receptor activity, to design and prioritize the synthesis of novel pharmacokinetically suitable ligands useful in the validation of bile acid-responsive receptors as therapeutic targets.

  13. Quantitative Analysis of Polarimetric Model-Based Decomposition Methods

    Directory of Open Access Journals (Sweden)

    Qinghua Xie

    2016-11-01

    Full Text Available In this paper, we analyze the robustness of the parameter inversion provided by general polarimetric model-based decomposition methods from the perspective of a quantitative application. The general model and algorithm we have studied is the method proposed recently by Chen et al., which makes use of the complete polarimetric information and outperforms traditional decomposition methods in terms of feature extraction from land covers. Nevertheless, a quantitative analysis on the retrieved parameters from that approach suggests that further investigations are required in order to fully confirm the links between a physically-based model (i.e., approaches derived from the Freeman–Durden concept and its outputs as intermediate products before any biophysical parameter retrieval is addressed. To this aim, we propose some modifications on the optimization algorithm employed for model inversion, including redefined boundary conditions, transformation of variables, and a different strategy for values initialization. A number of Monte Carlo simulation tests for typical scenarios are carried out and show that the parameter estimation accuracy of the proposed method is significantly increased with respect to the original implementation. Fully polarimetric airborne datasets at L-band acquired by German Aerospace Center’s (DLR’s experimental synthetic aperture radar (E-SAR system were also used for testing purposes. The results show different qualitative descriptions of the same cover from six different model-based methods. According to the Bragg coefficient ratio (i.e., β , they are prone to provide wrong numerical inversion results, which could prevent any subsequent quantitative characterization of specific areas in the scene. Besides the particular improvements proposed over an existing polarimetric inversion method, this paper is aimed at pointing out the necessity of checking quantitatively the accuracy of model-based PolSAR techniques for a

  14. Quantitative structure-activity relationships of antimicrobial fatty acids and derivatives against Staphylococcus aureus

    Institute of Scientific and Technical Information of China (English)

    Hui ZHANG; Lu ZHANG; Li-juan PENG; Xiao-wu DONG; Di WU; Vivian Chi-Hua WU; Feng-qin FENG

    2012-01-01

    Fatty acids and derivatives (FADs) are resources for natural antimicrobials.In order to screen for additional potent antimicrobial agents,the antimicrobial activities of FADs against Staphylococcus aureus were examined using a microplate assay.Monoglycerides of fatty acids were the most potent class of fatty acids,among which monotridecanoin possessed the most potent antimicrobial activity.The conventional quantitative structure-activity relationship (QSAR) and comparative molecular field analysis (CoMFA) were performed to establish two statistically reliable models (conventional QSAR:R2=0.942,Q2LOO=0.910; CoMFA:R2=0.979,Q2=0.588,respectively).Improved forecasting can be achieved by the combination of these two models that provide a good insight into the structureactivity relationships of the FADs and that may be useful to design new FADs as antimicrobial agents.

  15. Assessing the robustness of quantitative fatty acid signature analysis to assumption violations

    Science.gov (United States)

    Bromaghin, Jeffrey; Budge, Suzanne M.; Thiemann, Gregory W.; Rode, Karyn D.

    2016-01-01

      Knowledge of animal diets can provide important insights into life history and ecology, relationships among species in a community and potential response to ecosystem change or perturbation. Quantitative fatty acid signature analysis (QFASA) is a method of estimating diets from data on the composition, or signature, of fatty acids stored in adipose tissue. Given data on signatures of potential prey, a predator diet is estimated by minimizing the distance between its signature and a mixture of prey signatures. Calibration coefficients, constants derived from feeding trials, are used to account for differential metabolism of individual fatty acids. QFASA has been widely applied since its introduction and several variants of the original estimator have appeared in the literature. However, work to compare the statistical properties of QFASA estimators has been limited.

  16. Wavelength Selection Method Based on Differential Evolution for Precise Quantitative Analysis Using Terahertz Time-Domain Spectroscopy.

    Science.gov (United States)

    Li, Zhi; Chen, Weidong; Lian, Feiyu; Ge, Hongyi; Guan, Aihong

    2017-01-01

    Quantitative analysis of component mixtures is an important application of terahertz time-domain spectroscopy (THz-TDS) and has attracted broad interest in recent research. Although the accuracy of quantitative analysis using THz-TDS is affected by a host of factors, wavelength selection from the sample's THz absorption spectrum is the most crucial component. The raw spectrum consists of signals from the sample and scattering and other random disturbances that can critically influence the quantitative accuracy. For precise quantitative analysis using THz-TDS, the signal from the sample needs to be retained while the scattering and other noise sources are eliminated. In this paper, a novel wavelength selection method based on differential evolution (DE) is investigated. By performing quantitative experiments on a series of binary amino acid mixtures using THz-TDS, we demonstrate the efficacy of the DE-based wavelength selection method, which yields an error rate below 5%.

  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. Analysis of quantitative pore features based on mathematical morphology

    Institute of Scientific and Technical Information of China (English)

    QI Heng-nian; CHEN Feng-nong; WANG Hang-jun

    2008-01-01

    Wood identification is a basic technique of wood science and industry. Pore features are among the most important identification features for hardwoods. We have used a method based on an analysis of quantitative pore feature, which differs from traditional qualitative methods. We applies mathematical morphology methods such as dilation and erosion, open and close transformation of wood cross-sections, image repairing, noise filtering and edge detection to segment the pores from their background. Then the mean square errors (MSE) of pores were computed to describe the distribution of pores. Our experiment shows that it is easy to classift the pore features into three basic types, just as in traditional qualitative methods, but with the use of MSE of pores. This quantitative method improves wood identification considerably.

  19. Kinetics and Quantitative Structure—Activity Relationship Study on the Degradation Reaction from Perfluorooctanoic Acid to Trifluoroacetic Acid

    Directory of Open Access Journals (Sweden)

    Chen Gong

    2014-08-01

    Full Text Available Investigation of the degradation kinetics of perfluorooctanoic acid (PFOA has been carried out to calculate rate constants of the main elementary reactions using the multichannel Rice-Ramsperger-Kassel-Marcus theory and canonical variational transition state theory with small-curvature tunneling correction over a temperature range of 200~500 K. The Arrhenius equations of rate constants of elementary reactions are fitted. The decarboxylation is role step in the degradation mechanism of PFOA. For the perfluorinated carboxylic acids from perfluorooctanoic acid to trifluoroacetic acid, the quantitative structure–activity relationship of the decarboxylation was analyzed with the genetic function approximation method and the structure–activity model was constructed. The main parameters governing rate constants of the decarboxylation reaction from the eight-carbon chain to the two-carbon chain were obtained. As the structure–activity model shows, the bond length and energy of C1–C2 (RC1–C2 and EC1–C2 are positively correlated to rate constants, while the volume (V, the energy difference between EHOMO and ELUMO (ΔE, and the net atomic charges on atom C2 (QC2 are negatively correlated.

  20. Particle concentration measurement of virus samples using electrospray differential mobility analysis and quantitative amino acid analysis.

    Science.gov (United States)

    Cole, Kenneth D; Pease, Leonard F; Tsai, De-Hao; Singh, Tania; Lute, Scott; Brorson, Kurt A; Wang, Lili

    2009-07-24

    Virus reference materials are needed to develop and calibrate detection devices and instruments. We used electrospray differential mobility analysis (ES-DMA) and quantitative amino acid analysis (AAA) to determine the particle concentration of three small model viruses (bacteriophages MS2, PP7, and phiX174). The biological activity, purity, and aggregation of the virus samples were measured using plaque assays, denaturing gel electrophoresis, and size-exclusion chromatography. ES-DMA was developed to count the virus particles using gold nanoparticles as internal standards. ES-DMA additionally provides quantitative measurement of the size and extent of aggregation in the virus samples. Quantitative AAA was also used to determine the mass of the viral proteins in the pure virus samples. The samples were hydrolyzed and the masses of the well-recovered amino acids were used to calculate the equivalent concentration of viral particles in the samples. The concentration of the virus samples determined by ES-DMA was in good agreement with the concentration predicted by AAA for these purified samples. The advantages and limitations of ES-DMA and AAA to characterize virus reference materials are discussed.

  1. Trophic relationships in an estuarine environment: A quantitative fatty acid analysis signature approach

    Science.gov (United States)

    Magnone, Larisa; Bessonart, Martin; Gadea, Juan; Salhi, María

    2015-12-01

    In order to better understand the functioning of aquatic environments, it is necessary to obtain accurate diet estimations in food webs. Their description should incorporate information about energy flow and the relative importance of trophic pathways. Fatty acids have been extensively used in qualitative studies on trophic relationships in food webs. Recently a new method to estimate quantitatively single predator diet has been developed. In this study, a model of aquatic food web through quantitative fatty acid signature analysis was generated to identify the trophic interactions among the species in the Rocha Lagoon. The biological sampling over two consecutive annual periods was comprehensive enough to identify all functional groups in the aquatic food web (except birds and mammals). Heleobia australis seemed to play a central role in this estuarine ecosystem. As both, a grazer and a prey to several other species, probably H. australis is transferring a great amount of energy to upper trophic levels. Most of the species at Rocha Lagoon have a wide range of prey items in their diet reflecting a complex food web, which is characteristic of extremely dynamic environment as estuarine ecosystems. QFASA is a model in tracing and quantitative estimate trophic pathways among species in an estuarine food web. The results obtained in the present work are a valuable contribution in the understanding of trophic relationships in Rocha Lagoon.

  2. Plant SILAC: stable-isotope labelling with amino acids of arabidopsis seedlings for quantitative proteomics.

    Directory of Open Access Journals (Sweden)

    Dominika Lewandowska

    Full Text Available Stable Isotope Labelling by Amino acids in Cell culture (SILAC is a powerful technique for comparative quantitative proteomics, which has recently been applied to a number of different eukaryotic organisms. Inefficient incorporation of labelled amino acids in cell cultures of Arabidopsis thaliana has led to very limited use of SILAC in plant systems. We present a method allowing, for the first time, efficient labelling with stable isotope-containing arginine and lysine of whole Arabidopsis seedlings. To illustrate the utility of this method, we have combined the high labelling efficiency (>95% with quantitative proteomics analyses of seedlings exposed to increased salt concentration. In plants treated for 7 days with 80 mM NaCl, a relatively mild salt stress, 215 proteins were identified whose expression levels changed significantly compared to untreated seedling controls. The 92 up-regulated proteins included proteins involved in abiotic stress responses and photosynthesis, while the 123 down-regulated proteins were enriched in proteins involved in reduction of oxidative stress and other stress responses, respectively. Efficient labelling of whole Arabidopsis seedlings by this modified SILAC method opens new opportunities to exploit the genetic resources of Arabidopsis and analyse the impact of mutations on quantitative protein dynamics in vivo.

  3. Nucleic Acid-Based Nanoconstructs

    Science.gov (United States)

    Focuses on the design, synthesis, characterization, and development of spherical nucleic acid constructs as effective nanotherapeutic, single-entity agents for the treatment of glioblastoma multiforme and prostate cancers.

  4. Quantitative prediction of 3D solution shape and flexibility of nucleic acid nanostructures.

    Science.gov (United States)

    Kim, Do-Nyun; Kilchherr, Fabian; Dietz, Hendrik; Bathe, Mark

    2012-04-01

    DNA nanotechnology enables the programmed synthesis of intricate nanometer-scale structures for diverse applications in materials and biological science. Precise control over the 3D solution shape and mechanical flexibility of target designs is important to achieve desired functionality. Because experimental validation of designed nanostructures is time-consuming and cost-intensive, predictive physical models of nanostructure shape and flexibility have the capacity to enhance dramatically the design process. Here, we significantly extend and experimentally validate a computational modeling framework for DNA origami previously presented as CanDo [Castro,C.E., Kilchherr,F., Kim,D.-N., Shiao,E.L., Wauer,T., Wortmann,P., Bathe,M., Dietz,H. (2011) A primer to scaffolded DNA origami. Nat. Meth., 8, 221-229.]. 3D solution shape and flexibility are predicted from basepair connectivity maps now accounting for nicks in the DNA double helix, entropic elasticity of single-stranded DNA, and distant crossovers required to model wireframe structures, in addition to previous modeling (Castro,C.E., et al.) that accounted only for the canonical twist, bend and stretch stiffness of double-helical DNA domains. Systematic experimental validation of nanostructure flexibility mediated by internal crossover density probed using a 32-helix DNA bundle demonstrates for the first time that our model not only predicts the 3D solution shape of complex DNA nanostructures but also their mechanical flexibility. Thus, our model represents an important advance in the quantitative understanding of DNA-based nanostructure shape and flexibility, and we anticipate that this model will increase significantly the number and variety of synthetic nanostructures designed using nucleic acids.

  5. Identification and quantitation of new glutamic acid derivatives in soy sauce by UPLC/MS/MS.

    Science.gov (United States)

    Frerot, Eric; Chen, Ting

    2013-10-01

    Glutamic acid is an abundant amino acid that lends a characteristic umami taste to foods. In fermented foods, glutamic acid can be found as a free amino acid formed by proteolysis or as a non-proteolytic derivative formed by microorganisms. The aim of the present study was to identify different structures of glutamic acid derivatives in a typical fermented protein-based food product, soy sauce. An acidic fraction was prepared with anion-exchange solid-phase extraction (SPE) and analyzed by UPLC/MS/MS and UPLC/TOF-MS. α-Glutamyl, γ-glutamyl, and pyroglutamyl dipeptides, as well as lactoyl amino acids, were identified in the acidic fraction of soy sauce. They were chemically synthesized for confirmation of their occurrence and quantified in the selected reaction monitoring (SRM) mode. Pyroglutamyl dipeptides accounted for 770 mg/kg of soy sauce, followed by lactoyl amino acids (135 mg/kg) and γ-glutamyl dipeptides (70 mg/kg). In addition, N-succinoylglutamic acid was identified for the first time in food as a minor compound in soy sauce (5 mg/kg).

  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. Students' Alternate Conceptions on Acids and Bases

    Science.gov (United States)

    Pan, Hanqing; Henriques, Laura

    2015-01-01

    Knowing what students bring to the classroom can and should influence how we teach them. This study is a review of the literature associated with secondary and postsecondary students' ideas about acids and bases. It was found that there are six types of alternate ideas about acids and bases that students hold. These are: macroscopic properties of…

  9. 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…

  10. Semiconductor defect metrology using laser-based quantitative phase imaging

    Science.gov (United States)

    Zhou, Renjie; Edwards, Chris; Popescu, Gabriel; Goddard, Lynford

    2015-03-01

    A highly sensitive laser-based quantitative phase imaging tool, using an epi-illumination diffraction phase microscope, has been developed for silicon wafer defect inspection. The first system used a 532 nm solid-state laser and detected 20 nm by 100 nm by 110 nm defects in a 22 nm node patterned silicon wafer. The second system, using a 405 nm diode laser, is more sensitive and has enabled detection of 15 nm by 90 nm by 35 nm defects in a 9 nm node densely patterned silicon wafer. In addition to imaging, wafer scanning and image-post processing are also crucial for defect detection.

  11. Recent progress in quantitative analysis of DNA adducts of nephrotoxin aristolochic acid

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Aristolochic acid (AA), a mixture of structure-related nitrophenanthrene carboxylic acid derivatives derived from Aristolochia spp, is associated with nephrotoxin and carcinogen. AA-DNA adducts induced by reductive metabolic activation of AA were detected in tissues of animals and in patients exposed to AA. The DNA adducts were generally used as biomarkers in toxicological study of AA. In this short review, quantitative analysis of AA-DNA adducts in various in vitro and in vivo systems by using 32P-postlabelling assay, HPLC-UV, HPLC-radiation monitor, HPLC-FLD, HPLC-ESI/MS and UPLC-MS/MS methods is discussed. The distribution of AA-DNA adducts in various tissues is also summarized.

  12. Quantitative structure-activity relationship study on the biodegradation of acid dyestuffs

    Institute of Scientific and Technical Information of China (English)

    LI Yin; XI Dan-li

    2007-01-01

    Quantitative structure-biodegradability relationships (QSBRs) were established to develop predictive models and mechanistic explanations for acid dyestuffs as well as biological activities. With a total of four descriptors, molecular weight (MW), energies of the highest occupied molecular orbital (EHOMO), the lowest unoccupied molecular orbital (ELUMO), and the excited state (EES), calculated using quantum chemical semi-empirical methodology, a series of models were analyzed between the dye biodegradability and each descriptor. Results showed that EHOMO and MW were the dominant parameters controlling the biodegradability of acid dyes. A statistically robust QSBR model was developed for all studied dyes, with the combined application of EHOMO and MW. The calculated biodegradations fitted well with the experimental data monitored in a facultative-aerobic process, indicative of the reliable prediction and mechanistic character of the developed model.

  13. Phenotypic and quantitative relationship of red cell acid phosphatase with haemoglobin, haptoglobin, and G6PD phenotypes.

    Science.gov (United States)

    Saha, N; Patgunarajah, N

    1981-08-01

    The phenotypic and quantitative relationship of red cell acid phosphatase with haemoglobin, haptoglobin, and G6PD phenotypes was investigated in three populations in the Sudan and one population in Nilgiris, India. No significant consistent association of red cell acid phosphatase phenotypes was observed with these polymorphisms. However, there was a lack of acid phosphatase AB in G6PD deficient subjects from Nilgiris. The relative quantitative expression of red cell acid phosphatase genes PA, PB, and PC was 1.0, 1.2, and 1.3, respectively. The red cell acid phosphatase activity was higher (15%) in the presence of raised haemoglobin A2 and in sickle cell anaemia (21%). Those with Hp2 had 18% higher level of acid phosphatase than those with Hp1. G6PD deficient subjects had a lower level of acid phosphatase activity (20%) than those with normal G6PD activity.

  14. Mapping quantitative trait loci (QTLs for fatty acid composition in an interspecific cross of oil palm

    Directory of Open Access Journals (Sweden)

    Sharma Mukesh

    2009-08-01

    Full Text Available Abstract Background Marker Assisted Selection (MAS is well suited to a perennial crop like oil palm, in which the economic products are not produced until several years after planting. The use of DNA markers for selection in such crops can greatly reduce the number of breeding cycles needed. With the use of DNA markers, informed decisions can be made at the nursery stage, regarding which individuals should be retained as breeding stock, which are satisfactory for agricultural production, and which should be culled. The trait associated with oil quality, measured in terms of its fatty acid composition, is an important agronomic trait that can eventually be tracked using molecular markers. This will speed up the production of new and improved oil palm planting materials. Results A map was constructed using AFLP, RFLP and SSR markers for an interspecific cross involving a Colombian Elaeis oleifera (UP1026 and a Nigerian E. guinneensis (T128. A framework map was generated for the male parent, T128, using Joinmap ver. 4.0. In the paternal (E. guineensis map, 252 markers (199 AFLP, 38 RFLP and 15 SSR could be ordered in 21 linkage groups (1815 cM. Interval mapping and multiple-QTL model (MQM mapping (also known as composite interval mapping, CIM were used to detect quantitative trait loci (QTLs controlling oil quality (measured in terms of iodine value and fatty acid composition. At a 5% genome-wide significance threshold level, QTLs associated with iodine value (IV, myristic acid (C14:0, palmitic acid (C16:0, palmitoleic acid (C16:1, stearic acid (C18:0, oleic acid (C18:1 and linoleic acid (C18:2 content were detected. One genomic region on Group 1 appears to be influencing IV, C14:0, C16:0, C18:0 and C18:1 content. Significant QTL for C14:0, C16:1, C18:0 and C18:1 content was detected around the same locus on Group 15, thus revealing another major locus influencing fatty acid composition in oil palm. Additional QTL for C18:0 was detected on Group 3

  15. Effective correction of experimental errors in quantitative proteomics using stable isotope labeling by amino acids in cell culture (SILAC)

    Science.gov (United States)

    Park, Sung-Soo; Wu, Wells W.; Zhou, Yu; Shen, Rong-Fong; Martin, Bronwen; Maudsley, Stuart

    2012-01-01

    Accurate and reliable quantitative proteomics in cell culture has been considerably facilitated by the introduction of the stable isotope labeling by amino acids in cell culture (SILAC), combined with high resolution mass spectrometry. There are however several major sources of quantification errors that commonly occur with SILAC techniques, i.e. incomplete incorporation of isotopic amino acids, arginine-to-proline conversion, and experimental errors in final sample mixing. Dataset normalization is a widely adopted solution to such errors, however this may not completely prevent introducing incorrect expression ratios. Here we demonstrate that a label-swap replication of SILAC experiments was able to effectively correct experimental errors by averaging ratios measured in individual replicates using quantitative proteomics and phosphoproteomics of ligand treatment of neural cell cultures. Furthermore, this strategy was successfully applied to a SILAC triplet experiment, which presents a much more complicated experimental matrix, affected by both incomplete labeling and arginine-to-proline conversion. Based on our results, we suggest that SILAC experiments should be designed to incorporate label-swap replications for enhanced reliability in expression ratios. PMID:22575385

  16. Smartphone based visual and quantitative assays on upconversional paper sensor.

    Science.gov (United States)

    Mei, Qingsong; Jing, Huarong; Li, You; Yisibashaer, Wuerzha; Chen, Jian; Nan Li, Bing; Zhang, Yong

    2016-01-15

    The integration of smartphone with paper sensors recently has been gain increasing attentions because of the achievement of quantitative and rapid analysis. However, smartphone based upconversional paper sensors have been restricted by the lack of effective methods to acquire luminescence signals on test paper. Herein, by the virtue of 3D printing technology, we exploited an auxiliary reusable device, which orderly assembled a 980nm mini-laser, optical filter and mini-cavity together, for digitally imaging the luminescence variations on test paper and quantitative analyzing pesticide thiram by smartphone. In detail, copper ions decorated NaYF4:Yb/Tm upconversion nanoparticles were fixed onto filter paper to form test paper, and the blue luminescence on it would be quenched after additions of thiram through luminescence resonance energy transfer mechanism. These variations could be monitored by the smartphone camera, and then the blue channel intensities of obtained colored images were calculated to quantify amounts of thiram through a self-written Android program installed on the smartphone, offering a reliable and accurate detection limit of 0.1μM for the system. This work provides an initial demonstration of integrating upconversion nanosensors with smartphone digital imaging for point-of-care analysis on a paper-based platform.

  17. Quantitative Assessment of Amino Acid Damage upon keV Ion Beam Irradiation Through FTIR Spectroscopy

    Science.gov (United States)

    Huang, Qing; Ke, Zhigang; Su, Xi; Yuan, Hang; Zhang, Shuqing; Yu, Zengliang

    2010-06-01

    Ion beam irradiation induces important biological effects and it is a long-standing task to acquire both qualitative and quantitative assessment of these effects. One effective way in the investigation is to utilize Fourier transformation infrared (FTIR) spectroscopy because it can offer sensitive and non-invasive measurements. In this paper a novel protocol was employed to prepare biomolecular samples in the form of thin and transversely uniform solid films that were suitable for both infrared and low-energy ion beam irradiation experiments. Under the irradiation of N+ and Ar+ ion beams of 25 keV with fluence ranging from 5×1015 ions/cm2 to 2.5×10 ions/cm2, the ion radio-sensitivity of four amino acids, namely, glycine, tyrosine, methionine and phenylalanine, were evaluated and compared. The ion beam irradiation caused biomolecular decomposition accompanied by molecular desorption of volatile species and the damage was dependent on ion type, fluence, energy and types of amino acids. The effectiveness of application of FTIR spectroscopy to the quantitative assessment of biomolecular damage dose effect induced by low-energy ion radiation was thus demonstrated.

  18. Fusing Quantitative Requirements Analysis with Model-based Systems Engineering

    Science.gov (United States)

    Cornford, Steven L.; Feather, Martin S.; Heron, Vance A.; Jenkins, J. Steven

    2006-01-01

    A vision is presented for fusing quantitative requirements analysis with model-based systems engineering. This vision draws upon and combines emergent themes in the engineering milieu. "Requirements engineering" provides means to explicitly represent requirements (both functional and non-functional) as constraints and preferences on acceptable solutions, and emphasizes early-lifecycle review, analysis and verification of design and development plans. "Design by shopping" emphasizes revealing the space of options available from which to choose (without presuming that all selection criteria have previously been elicited), and provides means to make understandable the range of choices and their ramifications. "Model-based engineering" emphasizes the goal of utilizing a formal representation of all aspects of system design, from development through operations, and provides powerful tool suites that support the practical application of these principles. A first step prototype towards this vision is described, embodying the key capabilities. Illustrations, implications, further challenges and opportunities are outlined.

  19. Fusing Quantitative Requirements Analysis with Model-based Systems Engineering

    Science.gov (United States)

    Cornford, Steven L.; Feather, Martin S.; Heron, Vance A.; Jenkins, J. Steven

    2006-01-01

    A vision is presented for fusing quantitative requirements analysis with model-based systems engineering. This vision draws upon and combines emergent themes in the engineering milieu. "Requirements engineering" provides means to explicitly represent requirements (both functional and non-functional) as constraints and preferences on acceptable solutions, and emphasizes early-lifecycle review, analysis and verification of design and development plans. "Design by shopping" emphasizes revealing the space of options available from which to choose (without presuming that all selection criteria have previously been elicited), and provides means to make understandable the range of choices and their ramifications. "Model-based engineering" emphasizes the goal of utilizing a formal representation of all aspects of system design, from development through operations, and provides powerful tool suites that support the practical application of these principles. A first step prototype towards this vision is described, embodying the key capabilities. Illustrations, implications, further challenges and opportunities are outlined.

  20. Strong Relationships in Acid-Base Chemistry – Modeling Protons Based on Predictable Concentrations of Strong Ions, Total Weak Acid Concentrations, and pCO2

    OpenAIRE

    2016-01-01

    Understanding acid-base regulation is often reduced to pigeonholing clinical states into categories of disorders based on arterial blood sampling. An earlier ambition to quantitatively explain disorders by measuring production and elimination of acid has not become standard clinical practice. Seeking back to classical physical chemistry we propose that in any compartment, the requirement of electroneutrality leads to a strong relationship between charged moieties. This relationship is derived...

  1. A microfabrication-based approach to quantitative isothermal titration calorimetry.

    Science.gov (United States)

    Wang, Bin; Jia, Yuan; Lin, Qiao

    2016-04-15

    Isothermal titration calorimetry (ITC) directly measures heat evolved in a chemical reaction to determine equilibrium binding properties of biomolecular systems. Conventional ITC instruments are expensive, use complicated design and construction, and require long analysis times. Microfabricated calorimetric devices are promising, although they have yet to allow accurate, quantitative ITC measurements of biochemical reactions. This paper presents a microfabrication-based approach to integrated, quantitative ITC characterization of biomolecular interactions. The approach integrates microfabricated differential calorimetric sensors with microfluidic titration. Biomolecules and reagents are introduced at each of a series of molar ratios, mixed, and allowed to react. The reaction thermal power is differentially measured, and used to determine the thermodynamic profile of the biomolecular interactions. Implemented in a microdevice featuring thermally isolated, well-defined reaction volumes with minimized fluid evaporation as well as highly sensitive thermoelectric sensing, the approach enables accurate and quantitative ITC measurements of protein-ligand interactions under different isothermal conditions. Using the approach, we demonstrate ITC characterization of the binding of 18-Crown-6 with barium chloride, and the binding of ribonuclease A with cytidine 2'-monophosphate within reaction volumes of approximately 0.7 µL and at concentrations down to 2mM. For each binding system, the ITC measurements were completed with considerably reduced analysis times and material consumption, and yielded a complete thermodynamic profile of the molecular interaction in agreement with published data. This demonstrates the potential usefulness of our approach for biomolecular characterization in biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Hard and soft acids and bases: atoms and atomic ions.

    Science.gov (United States)

    Reed, James L

    2008-07-07

    The structural origin of hard-soft behavior in atomic acids and bases has been explored using a simple orbital model. The Pearson principle of hard and soft acids and bases has been taken to be the defining statement about hard-soft behavior and as a definition of chemical hardness. There are a number of conditions that are imposed on any candidate structure and associated property by the Pearson principle, which have been exploited. The Pearson principle itself has been used to generate a thermodynamically based scale of relative hardness and softness for acids and bases (operational chemical hardness), and a modified Slater model has been used to discern the electronic origin of hard-soft behavior. Whereas chemical hardness is a chemical property of an acid or base and the operational chemical hardness is an experimental measure of it, the absolute hardness is a physical property of an atom or molecule. A critical examination of chemical hardness, which has been based on a more rigorous application of the Pearson principle and the availability of quantitative measures of chemical hardness, suggests that the origin of hard-soft behavior for both acids and bases resides in the relaxation of the electrons not undergoing transfer during the acid-base interaction. Furthermore, the results suggest that the absolute hardness should not be taken as synonymous with chemical hardness but that the relationship is somewhat more complex. Finally, this work provides additional groundwork for a better understanding of chemical hardness that will inform the understanding of hardness in molecules.

  3. Quantitative amino acid profiling and stable isotopically labeled amino acid tracer enrichment used for in vivo human systemic and tissue kinetics measurements

    DEFF Research Database (Denmark)

    Bornø, Andreas; van Hall, Gerrit

    2014-01-01

    /ion exchange, derivatized using a phenylisothiocyanate reagent and each amino acid was quantitated with its own stable isotopically labeled internal standard (uniformly labeled-(13)C/(15)N). The method was validated according to general recommendations for chromatographic analytical methods. The calibration...... and plasma were 4.4 and 0.8%, and the interday variability was 3.4% and the recovery was 90.5%, respectively. In conclusion, we have developed and validated a method for quantitative amino acid profiling that meets the requirements for systemic and tissue human in vivo amino acid and protein turnover...

  4. 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...

  5. Image based quantitative reader for Lateral flow immunofluorescence assay.

    Science.gov (United States)

    Chowdhury, Kaushik Basak; Joseph, Jayaraj; Sivaprakasam, Mohanasankar

    2015-08-01

    Fluorescence Lateral flow immunoassays (LFIA) have wide range of applications in point-of-care testing (POCT). An integrated, motion-free, accurate, reliable reader that performs automated quantitative analysis of LFIA is essential for POCT diagnosis. We demonstrate an image based quantitative method to read the lateral flow immunofluorescence test strips. The developed reader uses line laser diode module to illuminate the LFIA test strip having fluorescent dye. Fluorescence light coming from the region of interest (ROI) of the LFIA test strip was filtered using an emission filter and imaged using a camera following which images were processed in computer. A dedicated control program was developed that automated the entire process including illumination of the test strip using laser diode, capturing the ROI of the test strip, processing and analyzing the images and displaying of results. Reproducibility of the reader has been evaluated using few reference cartridges and HbA1c (Glycated haemoglobin) test cartridges. The proposed system can be upgraded to a compact reader for widespread testing of LFIA test strips.

  6. Whole body acid-base modeling revisited.

    Science.gov (United States)

    Ring, Troels; Nielsen, Søren

    2017-04-01

    The textbook account of whole body acid-base balance in terms of endogenous acid production, renal net acid excretion, and gastrointestinal alkali absorption, which is the only comprehensive model around, has never been applied in clinical practice or been formally validated. To improve understanding of acid-base modeling, we managed to write up this conventional model as an expression solely on urine chemistry. Renal net acid excretion and endogenous acid production were already formulated in terms of urine chemistry, and we could from the literature also see gastrointestinal alkali absorption in terms of urine excretions. With a few assumptions it was possible to see that this expression of net acid balance was arithmetically identical to minus urine charge, whereby under the development of acidosis, urine was predicted to acquire a net negative charge. The literature already mentions unexplained negative urine charges so we scrutinized a series of seminal papers and confirmed empirically the theoretical prediction that observed urine charge did acquire negative charge as acidosis developed. Hence, we can conclude that the conventional model is problematic since it predicts what is physiologically impossible. Therefore, we need a new model for whole body acid-base balance, which does not have impossible implications. Furthermore, new experimental studies are needed to account for charge imbalance in urine under development of acidosis.

  7. Quantitative metabolomics analysis of amino acid metabolism in recombinant Pichia pastoris under different oxygen availability conditions

    Directory of Open Access Journals (Sweden)

    Carnicer Marc

    2012-06-01

    Full Text Available Abstract Background Environmental and intrinsic stress factors can result in the global alteration of yeast physiology, as evidenced by several transcriptional studies. Hypoxia has been shown to have a beneficial effect on the expression of recombinant proteins in Pichia pastoris growing on glucose. Furthermore, transcriptional profiling analyses revealed that oxygen availability was strongly affecting ergosterol biosynthesis, central carbon metabolism and stress responses, in particular the unfolded protein response. To contribute to the better understanding of the effect and interplay of oxygen availability and foreign protein secretion on central metabolism, a first quantitative metabolomic analysis of free amino acids pools in a recombinant P. pastoris strain growing under different oxygen availability conditions has been performed. Results The values obtained indicate significant variations in the intracellular amino acid pools due to different oxygen availability conditions, showing an overall increase of their size under oxygen limitation. Notably, even while foreign protein productivities were relatively low (about 40–80 μg Fab/gDCW·h, recombinant protein production was found to have a limited but significant impact on the intracellular amino acid pools, which were generally decreased in the producing strain compared with the reference strain. However, observed changes in individual amino acids pools were not correlated with their corresponding relative abundance in the recombinant protein sequence, but to the overall cell protein amino acid compositional variations. Conclusions Overall, the results obtained, combined with previous transcriptomic and proteomic analyses provide a systematic metabolic fingerprint of the oxygen availability impact on recombinant protein production in P. pastoris.

  8. Acid-base disorders: learning the basics.

    Science.gov (United States)

    Ayers, Phil; Dixon, Carman; Mays, Andrew

    2015-02-01

    Nutrition support practitioners should be confident in their ability to recognize and treat various metabolic and respiratory disorders encountered in daily practice. A clinician's comprehension of the underlying physiologic processes and/or exogenous causes that occur during acid-base disorders is essential when making therapeutic decisions regarding fluids, parenteral nutrition, and electrolyte management. This invited review will discuss basic metabolic and respiratory disorders while briefly addressing mixed acid-base disorders. © 2014 American Society for Parenteral and Enteral Nutrition.

  9. Quantitative determination of uric acid using CdTe nanoparticles as fluorescence probes.

    Science.gov (United States)

    Jin, Dongri; Seo, Min-Ho; Huy, Bui The; Pham, Quoc-Thai; Conte, Maxwell L; Thangadurai, Daniel; Lee, Yong-Ill

    2016-03-15

    A convenient enzymatic optical method for uric acid detection was developed based on the fluorescence quenching of ligand-capped CdTe nanoparticles by H2O2 which was generated from the enzymatic reaction of uric acid. The interactions between the CdTe nanoparticles capped with different ligands (glutathione, 3-mercaptopropionic acid, and thioglycerol) and H2O2 were investigated. The fluorescence quenching studies of GSH-capped CdTe nanoparticles demonstrated an excellent sensitivity to H2O2. The effects of uric acid, uricase and H2O2 on the fluorescence intensity of CdTe nanoparticles were also explored. The detection conditions, reaction time, pH value, incubation period and the concentration of uricase and uric acid were optimized. The detection limit of uric acid was found to be 0.10 µM and the linear range was 0.22-6 µM under the optimized experimental conditions. These results typify that CdTe nanoparticles could be used as a fluorescent probe for uric acid detection.

  10. Identification and quantitation of urinary dicarboxylic acids as their dicyclohexyl esters in disease states by gas chromatography mass spectrometry.

    Science.gov (United States)

    Norman, E J; Berry, H K; Denton, M D

    1979-12-01

    Clinical studies were conducted by gas chromatography mass spectrometry selected ion monitoring of urinary dicarboxylic acids as dicyclohexyl esters. The dicyclohexyl esters of the dicarboxylic acids give characteristic electron impact mass spectra suitable for selected ion monitoring. The mass spectra exhibit a prominent acid + 1H ion and an (acid + 1H)-H2O ion for use as quantitating and confirming ions. The cyclohexyl esters are stable for days at room temperature and have excellent chromatographic properties. Dicarboxylic acid quantitation is performed within one hour using only 50 microliter of unpurified urine. A rapid method specifically for methylmalonic acid quantitation is described which has assisted physicians in the diagnosis of pernicious anemia and methylmalonic aciduria. This procedure is applicable for screening urinary organic acids for detection of inborn errors of metabolism. The detection of a child with elevated medium length dicarboxylic acids in the terminal urine specimen is reported. This condition, previously described as an inborn error, is attributed to a terminal event. Finally, an increase in urinary succinic acid paralleling putrescine levels is described during a response to cancer chemotherapy.

  11. Quantitative Monte Carlo-based holmium-166 SPECT reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Elschot, Mattijs; Smits, Maarten L. J.; Nijsen, Johannes F. W.; Lam, Marnix G. E. H.; Zonnenberg, Bernard A.; Bosch, Maurice A. A. J. van den; Jong, Hugo W. A. M. de [Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Viergever, Max A. [Image Sciences Institute, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)

    2013-11-15

    Purpose: Quantitative imaging of the radionuclide distribution is of increasing interest for microsphere radioembolization (RE) of liver malignancies, to aid treatment planning and dosimetry. For this purpose, holmium-166 ({sup 166}Ho) microspheres have been developed, which can be visualized with a gamma camera. The objective of this work is to develop and evaluate a new reconstruction method for quantitative {sup 166}Ho SPECT, including Monte Carlo-based modeling of photon contributions from the full energy spectrum.Methods: A fast Monte Carlo (MC) simulator was developed for simulation of {sup 166}Ho projection images and incorporated in a statistical reconstruction algorithm (SPECT-fMC). Photon scatter and attenuation for all photons sampled from the full {sup 166}Ho energy spectrum were modeled during reconstruction by Monte Carlo simulations. The energy- and distance-dependent collimator-detector response was modeled using precalculated convolution kernels. Phantom experiments were performed to quantitatively evaluate image contrast, image noise, count errors, and activity recovery coefficients (ARCs) of SPECT-fMC in comparison with those of an energy window-based method for correction of down-scattered high-energy photons (SPECT-DSW) and a previously presented hybrid method that combines MC simulation of photopeak scatter with energy window-based estimation of down-scattered high-energy contributions (SPECT-ppMC+DSW). Additionally, the impact of SPECT-fMC on whole-body recovered activities (A{sup est}) and estimated radiation absorbed doses was evaluated using clinical SPECT data of six {sup 166}Ho RE patients.Results: At the same noise level, SPECT-fMC images showed substantially higher contrast than SPECT-DSW and SPECT-ppMC+DSW in spheres ≥17 mm in diameter. The count error was reduced from 29% (SPECT-DSW) and 25% (SPECT-ppMC+DSW) to 12% (SPECT-fMC). ARCs in five spherical volumes of 1.96–106.21 ml were improved from 32%–63% (SPECT-DSW) and 50%–80

  12. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  13. Family-based bivariate association tests for quantitative traits.

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    Full Text Available The availability of a large number of dense SNPs, high-throughput genotyping and computation methods promotes the application of family-based association tests. While most of the current family-based analyses focus only on individual traits, joint analyses of correlated traits can extract more information and potentially improve the statistical power. However, current TDT-based methods are low-powered. Here, we develop a method for tests of association for bivariate quantitative traits in families. In particular, we correct for population stratification by the use of an integration of principal component analysis and TDT. A score test statistic in the variance-components model is proposed. Extensive simulation studies indicate that the proposed method not only outperforms approaches limited to individual traits when pleiotropic effect is present, but also surpasses the power of two popular bivariate association tests termed FBAT-GEE and FBAT-PC, respectively, while correcting for population stratification. When applied to the GAW16 datasets, the proposed method successfully identifies at the genome-wide level the two SNPs that present pleiotropic effects to HDL and TG traits.

  14. PCA-based groupwise image registration for quantitative MRI.

    Science.gov (United States)

    Huizinga, W; Poot, D H J; Guyader, J-M; Klaassen, R; Coolen, B F; van Kranenburg, M; van Geuns, R J M; Uitterdijk, A; Polfliet, M; Vandemeulebroucke, J; Leemans, A; Niessen, W J; Klein, S

    2016-04-01

    Quantitative magnetic resonance imaging (qMRI) is a technique for estimating quantitative tissue properties, such as the T1 and T2 relaxation times, apparent diffusion coefficient (ADC), and various perfusion measures. This estimation is achieved by acquiring multiple images with different acquisition parameters (or at multiple time points after injection of a contrast agent) and by fitting a qMRI signal model to the image intensities. Image registration is often necessary to compensate for misalignments due to subject motion and/or geometric distortions caused by the acquisition. However, large differences in image appearance make accurate image registration challenging. In this work, we propose a groupwise image registration method for compensating misalignment in qMRI. The groupwise formulation of the method eliminates the requirement of choosing a reference image, thus avoiding a registration bias. The method minimizes a cost function that is based on principal component analysis (PCA), exploiting the fact that intensity changes in qMRI can be described by a low-dimensional signal model, but not requiring knowledge on the specific acquisition model. The method was evaluated on 4D CT data of the lungs, and both real and synthetic images of five different qMRI applications: T1 mapping in a porcine heart, combined T1 and T2 mapping in carotid arteries, ADC mapping in the abdomen, diffusion tensor mapping in the brain, and dynamic contrast-enhanced mapping in the abdomen. Each application is based on a different acquisition model. The method is compared to a mutual information-based pairwise registration method and four other state-of-the-art groupwise registration methods. Registration accuracy is evaluated in terms of the precision of the estimated qMRI parameters, overlap of segmented structures, distance between corresponding landmarks, and smoothness of the deformation. In all qMRI applications the proposed method performed better than or equally well as

  15. A procedure for the quantitative analysis of the sulphur amino acids of rat tissues.

    Science.gov (United States)

    Gaitonde, M K; Gaull, G E

    1967-03-01

    1. A method is described for the quantitative separation of the sulphur compounds in a single sample of tissue by passing an extract through a serial assembly of ion-exchange resins in the order: Dowex 2 (Cl(-) form), Dowex 1 (CO(3) (2-) form), Amberlite CG-50 (H(+) form) and Zeo-Karb 225 (H(+) form). 2. Groups of sulphur amino acids were eluted separately from each column; the recovery of sulphur compounds after their labelling with (35)S in vivo by injection of l-[(35)S]-methionine was 91-106%. Individual sulphur compounds were further resolved by one-dimensional or two-dimensional paper chromatography. 3. Evidence is presented on the occurrence of S-adenosylmethionine and S-adenosylhomocysteine in rat liver and brain. Rat liver and brain contained 83.6 and 31.4mmu-moles/g. respectively of S-adenosylmethionine.

  16. A descriptor of amino acids: SVRG and its application to peptide quantitative structure-activity relationship.

    Science.gov (United States)

    Tong, J; Che, T; Li, Y; Wang, P; Xu, X; Chen, Y

    2011-01-01

    In this work, a descriptor, SVRG (principal component scores vector of radial distribution function descriptors and geometrical descriptors), was derived from principal component analysis (PCA) of a matrix of two structural variables of coded amino acids, including radial distribution function index (RDF) and geometrical index. SVRG scales were then applied in three panels of peptide quantitative structure-activity relationships (QSARs) which were modelled by partial least squares regression (PLS). The obtained models with the correlation coefficient (R²(cum)), cross-validation correlation coefficient (Q²(LOO)) were 0.910 and 0.863 for 48 bitter-tasting dipeptides; 0.968 and 0.931 for 21 oxytocin analogues; and 0.992 and 0.954 for 20 thromboplastin inhibitors. Satisfactory results showed that SVRG contained much chemical information relating to bioactivities. The approach may be a useful structural expression methodology for studies on peptide QSAR.

  17. Quantitative analysis of oleic acid and three types of polyethers according to the number of hydroxy end groups in Polysorbate 80 by hydrophilic interaction chromatography at critical conditions.

    Science.gov (United States)

    Zhang, Rui; Wang, Yu; Ji, Yu; Shi, Bei-jia; Zhang, Zai-ping; Zhang, Hai-yan; Yang, Ming; Wang, Yong-mei

    2013-01-11

    A quantitative characterization of Polysorbate 80 is crucial for its many applications. In this paper we report a quick RP-HPLC method for the quantitative determination of Polysorbate 80. The hydrolysis of Polysorbate 80 to release oleic acid and three types of polyethers was first carried out. A chromatographic method based on liquid chromatography at critical conditions (LCCC) was then developed for an endgroup-based separation of low-molecular-mass polyether. With this method the polyether, irrespective of its molecular-mass, is separated according to endgroups (functionality) due to interactions of the polar endgroups with the hydrophilic stationary phase. The different types of polyethers and oleic acid were identified using on-line electrospray ionization mass spectrometry and quantified by evaporative light scattering detection.

  18. Synthesizing Quantitative Evidence for Evidence-based Nursing: Systematic Review

    Directory of Open Access Journals (Sweden)

    Eui Geum Oh, PhD, RN

    2016-06-01

    Full Text Available As evidence-based practice has become an important issue in healthcare settings, the educational needs for knowledge and skills for the generation and utilization of healthcare evidence are increasing. Systematic review (SR, a way of evidence generation, is a synthesis of primary scientific evidence, which summarizes the best evidence on a specific clinical question using a transparent, a priori protocol driven approach. SR methodology requires a critical appraisal of primary studies, data extraction in a reliable and repeatable way, and examination for validity of the results. SRs are considered hierarchically as the highest form of evidence as they are a systematic search, identification, and summarization of the available evidence to answer a focused clinical question with particular attention to the methodological quality of studies or the credibility of opinion and text. The purpose of this paper is to introduce an overview of the fundamental knowledge, principals and processes in SR. The focus of this paper is on SR especially for the synthesis of quantitative data from primary research studies that examines the effectiveness of healthcare interventions. To activate evidence-based nursing care in various healthcare settings, the best and available scientific evidence are essential components. This paper will include some examples to promote understandings.

  19. A quantitative test of infrared optical constants for supercooled sulphuric and nitric acid droplet aerosols

    Directory of Open Access Journals (Sweden)

    R. Wagner

    2003-05-01

    Full Text Available In situ Fourier transform infrared (FTIR extinction spectra of supercooled H2SO4/H2O and HNO3/H2O solution droplets were recorded in the large coolable aerosol chamber AIDA (Aerosol Interactions and Dynamics in the Atmosphere of Forschungszentrum Karlsruhe for a range of aerosol compositions and at temperatures extending down to 192 K. The measured spectra were quantitatively analysed in terms of aerosol composition and mass concentration by using Mie theory in combination with published refractive index data as input parameters. Simultaneously, total sulphuric acid and nitric acid mass concentrations from filter analysis and total water concentrations measured with the Lyman-a hygrometer of Forschungszentrum Jülich were used to calculate the aerosol composition at thermodynamic equilibrium inside the aerosol chamber. By comparing these measured aerosol parameters with those retrieved from the analysis of the FTIR spectra, the accuracy of the literature data sets of refractive indices could be assessed. In summary, four data sets were tested in the H2SO4/H2O system as well as two data sets in the HNO3/H2O system, partly revealing significant discrepancies in the retrieved aerosol properties. Potential explanations for these differences are discussed in this paper.

  20. PCR-free quantitative detection of genetically modified organism from raw materials. An electrochemiluminescence-based bio bar code method.

    Science.gov (United States)

    Zhu, Debin; Tang, Yabing; Xing, Da; Chen, Wei R

    2008-05-15

    A bio bar code assay based on oligonucleotide-modified gold nanoparticles (Au-NPs) provides a PCR-free method for quantitative detection of nucleic acid targets. However, the current bio bar code assay requires lengthy experimental procedures including the preparation and release of bar code DNA probes from the target-nanoparticle complex and immobilization and hybridization of the probes for quantification. Herein, we report a novel PCR-free electrochemiluminescence (ECL)-based bio bar code assay for the quantitative detection of genetically modified organism (GMO) from raw materials. It consists of tris-(2,2'-bipyridyl) ruthenium (TBR)-labeled bar code DNA, nucleic acid hybridization using Au-NPs and biotin-labeled probes, and selective capture of the hybridization complex by streptavidin-coated paramagnetic beads. The detection of target DNA is realized by direct measurement of ECL emission of TBR. It can quantitatively detect target nucleic acids with high speed and sensitivity. This method can be used to quantitatively detect GMO fragments from real GMO products.

  1. iTRAQ-Based Quantitative Proteomic Analysis of Spirulina platensis in Response to Low Temperature Stress.

    Science.gov (United States)

    Li, Qingye; Chang, Rong; Sun, Yijun; Li, Bosheng

    2016-01-01

    Low temperature (LT) is one of the most important abiotic stresses that can significantly reduce crop yield. To gain insight into how Spirulina responds to LT stress, comprehensive physiological and proteomic analyses were conducted in this study. Significant decreases in growth and pigment levels as well as excessive accumulation of compatible osmolytes were observed in response to LT stress. An isobaric tag for relative and absolute quantitation (iTRAQ)-based quantitative proteomics approach was used to identify changes in protein abundance in Spirulina under LT. A total of 3,782 proteins were identified, of which 1,062 showed differential expression. Bioinformatics analysis indicated that differentially expressed proteins that were enriched in photosynthesis, carbohydrate metabolism, amino acid biosynthesis, and translation are important for the maintenance of cellular homeostasis and metabolic balance in Spirulina when subjected to LT stress. The up-regulation of proteins involved in gluconeogenesis, starch and sucrose metabolism, and amino acid biosynthesis served as coping mechanisms of Spirulina in response to LT stress. Moreover, the down-regulated expression of proteins involved in glycolysis, TCA cycle, pentose phosphate pathway, photosynthesis, and translation were associated with reduced energy consumption. The findings of the present study allow a better understanding of the response of Spirulina to LT stress and may facilitate in the elucidation of mechanisms underlying LT tolerance.

  2. Quantitative structure-property relationship study of acidity constants of some 9,10-anthraquinone derivatives using multiple linear regression and partial least-squares procedures.

    Science.gov (United States)

    Shamsipur, M; Hemmateenejad, B; Akhond, M; Sharghi, H

    2001-07-06

    A quantitative structure-property relationship study is suggested for the prediction of acidity constants of some recently synthesized 9,10-anthraquinone derivatives in binary methanol-water mixtures. Modeling of the acidity constant of the anthraquinones as a function of physicochemical parameters and mole fraction of methanol was established by means of the partial least-squares algorithm based on singular value decomposition (PLS-SVD) and multiple linear regression. The PLS-SVD procedure resulted in a better prediction ability and was found to be insensitive to noneffective descriptors. The classification of anthraquinones by the calculated descriptors was established.

  3. Stability Test and Quantitative and Qualitative Analyses of the Amino Acids in Pharmacopuncture Extracted from Scolopendra subspinipes mutilans

    Science.gov (United States)

    Cho, GyeYoon; Han, KyuChul; Yoon, JinYoung

    2015-01-01

    Objectives: Scolopendra subspinipes mutilans (S. subspinipes mutilans) is known as a traditional medicine and includes various amino acids, peptides and proteins. The amino acids in the pharmacopuncture extracted from S. subspinipes mutilans by using derivatization methods were analyzed quantitatively and qualitatively by using high performance liquid chromatography (HPLC) over a 12 month period to confirm its stability. Methods: Amino acids of pharmacopuncture extracted from S. subspinipes mutilans were derived by using O-phthaldialdehyde (OPA) & 9-fluorenyl methoxy carbonyl chloride (FMOC) reagent and were analyzed using HPLC. The amino acids were detected by using a diode array detector (DAD) and a fluorescence detector (FLD) to compare a mixed amino acid standard (STD) to the pharmacopuncture from centipedes. The stability tests on the pharmacopuncture from centipedes were done using HPLC for three conditions: a room temperature test chamber, an acceleration test chamber, and a cold test chamber. Results: The pharmacopuncture from centipedes was prepared by using the method of the Korean Pharmacopuncture Institute (KPI) and through quantitative analyses was shown to contain 9 amino acids of the 16 amino acids in the mixed amino acid STD. The amounts of the amino acids in the pharmacopuncture from centipedes were 34.37 ppm of aspartate, 123.72 ppm of arginine, 170.63 ppm of alanine, 59.55 ppm of leucine and 57 ppm of lysine. The relative standard deviation (RSD %) results for the pharmacopuncture from centipedes had a maximum value of 14.95% and minimum value of 1.795% on the room temperature test chamber, the acceleration test chamber and the cold test chamber stability tests. Conclusion: Stability tests on and quantitative and qualitative analyses of the amino acids in the pharmacopuncture extracted from centipedes by using derivatization methods were performed by using HPLC. Through research, we hope to determine the relationship between time and the

  4. Slow erosion of a quantitative apple resistance to Venturia inaequalis based on an isolate-specific Quantitative Trait Locus.

    Science.gov (United States)

    Caffier, Valérie; Le Cam, Bruno; Al Rifaï, Mehdi; Bellanger, Marie-Noëlle; Comby, Morgane; Denancé, Caroline; Didelot, Frédérique; Expert, Pascale; Kerdraon, Tifenn; Lemarquand, Arnaud; Ravon, Elisa; Durel, Charles-Eric

    2016-10-01

    Quantitative plant resistance affects the aggressiveness of pathogens and is usually considered more durable than qualitative resistance. However, the efficiency of a quantitative resistance based on an isolate-specific Quantitative Trait Locus (QTL) is expected to decrease over time due to the selection of isolates with a high level of aggressiveness on resistant plants. To test this hypothesis, we surveyed scab incidence over an eight-year period in an orchard planted with susceptible and quantitatively resistant apple genotypes. We sampled 79 Venturia inaequalis isolates from this orchard at three dates and we tested their level of aggressiveness under controlled conditions. Isolates sampled on resistant genotypes triggered higher lesion density and exhibited a higher sporulation rate on apple carrying the resistance allele of the QTL T1 compared to isolates sampled on susceptible genotypes. Due to this ability to select aggressive isolates, we expected the QTL T1 to be non-durable. However, our results showed that the quantitative resistance based on the QTL T1 remained efficient in orchard over an eight-year period, with only a slow decrease in efficiency and no detectable increase of the aggressiveness of fungal isolates over time. We conclude that knowledge on the specificity of a QTL is not sufficient to evaluate its durability. Deciphering molecular mechanisms associated with resistance QTLs, genetic determinants of aggressiveness and putative trade-offs within pathogen populations is needed to help in understanding the erosion processes.

  5. Development and validation of a GC-FID method for quantitative analysis of oleic acid and related fatty acids☆

    Institute of Scientific and Technical Information of China (English)

    Honggen Zhang; Zhenyu Wang; Oscar Liu

    2015-01-01

    Oleic acid is a common pharmaceutical excipient that has been widely used in various dosage forms. Gas chromatography (GC) has often been used as the quantitation method for fatty acids normally requiring a derivatization step. The aim of this study was to develop a simple, robust, and derivatization-free GC method that is suitable for routine analysis of all the major components in oleic acid USP-NF (United States Pharmacopeia-National Formulary) material. A gas chromatography-flame ionization detection (GC-FID) method was developed for direct quantitative analysis of oleic acid and related fatty acids in oleic acid USP-NF material. Fifteen fatty acids were separated using a DB-FFAP (nitroterephthalic acid modified polyethylene glycol) capillary GC column (30 m × 0.32 mm i.d.) with a total run time of 20 min. The method was validated in terms of specificity, linearity, precision, accuracy, sensitivity, and robustness. The method can be routinely used for the purpose of oleic acid USP-NF material analysis.

  6. Acid-base balance in heart failure.

    Science.gov (United States)

    Frangiosa, A; De Santo, L S; Anastasio, P; De Santo, N G

    2006-01-01

    In end-stage heart failure, various acid-base disorders can be discovered due to the renal loss of hydrogen ions and hydrogen ion movements into cells, the reduction of the effective circulating volume, hypoxemia and renal failure. This justifies the occurrence of metabolic alkalosis, metabolic acidosis, respiratory alkalosis, as well as respiratory acidosis alone or in combination. Several studies have been published on the acid-base state in heart failure. In a 1951 study, Squires et al analyzed the distribution of body fluid in congestive heart failure by taking into consideration the abnormalities in serum electrolyte concentration and in acid-base equilibrium. A recent study by Milionis et al, analyzed 86 patients with congestive heart failure receiving conventional treatment; the majority of these patients exhibited hypokalemia, hyponatremia, hypocalcemia and hypophosphatemia. Disorders in acid-base balance were noted in 37.2% of patients. In a recent study, 70 patients with severe congestive heart failure before heart transplantation showed high-normal pH, slightly reduced pCO 2 and a slight loss of hydrogen ions. After heart transplantation, stability of blood pH and hydrogen ion concentrations was found. In contrast, bicarbonate and pCO 2 increased significantly. The data led us to formulate the diagnosis of a mixed acid-base disorder that includes respiratory alkalosis and metabolic alkalosis before heart transplantation. In heart failure, the presence of acid-base imbalance associated with the activation of mechanisms that lead to salt and water retention reveals evidence concerning the pivotal role of the kidney in determining the outcome of these patients.

  7. Radar-Derived Quantitative Precipitation Estimation Based on Precipitation Classification

    Directory of Open Access Journals (Sweden)

    Lili Yang

    2016-01-01

    Full Text Available A method for improving radar-derived quantitative precipitation estimation is proposed. Tropical vertical profiles of reflectivity (VPRs are first determined from multiple VPRs. Upon identifying a tropical VPR, the event can be further classified as either tropical-stratiform or tropical-convective rainfall by a fuzzy logic (FL algorithm. Based on the precipitation-type fields, the reflectivity values are converted into rainfall rate using a Z-R relationship. In order to evaluate the performance of this rainfall classification scheme, three experiments were conducted using three months of data and two study cases. In Experiment I, the Weather Surveillance Radar-1988 Doppler (WSR-88D default Z-R relationship was applied. In Experiment II, the precipitation regime was separated into convective and stratiform rainfall using the FL algorithm, and corresponding Z-R relationships were used. In Experiment III, the precipitation regime was separated into convective, stratiform, and tropical rainfall, and the corresponding Z-R relationships were applied. The results show that the rainfall rates obtained from all three experiments match closely with the gauge observations, although Experiment II could solve the underestimation, when compared to Experiment I. Experiment III significantly reduced this underestimation and generated the most accurate radar estimates of rain rate among the three experiments.

  8. 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.

  9. Separation and quantitation of phycobiliproteins using phytic acid in capillary electrophoresis with laser-induced fluorescence detection.

    Science.gov (United States)

    Viskari, Pertti J; Colyer, Christa L

    2002-10-01

    The similar electrophoretic mobilities and sizes of several of the phycobiliproteins, which are derived from the photosynthetic apparatus of cyanobacteria and eukaryotic algae, render their separation and quantitation a challenging problem. However, we have developed a suitable capillary electrophoresis (CE) method that employs a phytic acid-boric acid buffer and laser-induced fluorescence (LIF) detection with a single 594 nm He-Ne laser. This method takes advantage of the remarkably high quantum yields of these naturally fluorescent proteins, which can be attributed to their linear tetrapyrrole chromophores covalently bound to cysteinyl residues. As such, limits of detection of 1.18 x 10(-14), 5.26 x 10(-15), and 2.38 x 10(-15) mol/l were obtained for R-phycoerythrin, C-phycocyanin, and allophycocyanin proteins, respectively, with a linear dynamic range of eight orders of magnitude in each case. Unlike previously published CE-LIF methods, this work describes the separation of all three major classes of phycobiliproteins in under 5 min. Very good recoveries, ranging from 93.2 to 105.5%, were obtained for a standard mixture of the phycobiliproteins, based on seven-point calibration curves for both peak height and peak area. It is believed that this development will prove useful for the determination of phycobiliprotein content in naturally occurring cyanobacteria populations, thus providing a useful tool for understanding biological and chemical oceanographic processes.

  10. New insights into the diets of harbor seals in the Salish Sea revealed by quantitative fatty acid signature analysis

    Science.gov (United States)

    Bromaghin, Jeffrey F.; Lance, Monique M.; Elliott, Elizabeth W.; Jeffries, Steven J.; Acevedo-Gutiérrez, Alejandro; Kennish, John M.

    2012-01-01

    Harbor seals (Phoca vitulina) are an abundant predator along the west coast of North America, and there is considerable interest in their diet composition, especially in regard to predation on valued fish stocks. Available information on harbor seal diets, primarily derived from scat analysis, suggests that adult salmon (Oncorhynchus spp.), Pacific Herring (Clupea pallasii), and gadids predominate. Because diet assessments based on scat analysis may be biased, we investigated diet composition through quantitative analysis of fatty acid signatures. Blubber samples from 49 harbor seals captured in western North America from haul-outs within the area of the San Juan Islands and southern Strait of Georgia in the Salish Sea were analyzed for fatty acid composition, along with 269 fish and squid specimens representing 27 potential prey classes. Diet estimates varied spatially, demographically, and among individual harbor seals. Findings confirmed the prevalence of previously identified prey species in harbor seal diets, but other species also contributed significantly. In particular, Black (Sebastes melanops) and Yellowtail (S. flavidus) Rockfish were estimated to compose up to 50% of some individual seal diets. Specialization and high predation rates on Black and Yellowtail Rockfish by a subset of harbor seals may play a role in the population dynamics of these regional rockfish stocks that is greater than previously realized.

  11. Quantitative interferometric microscopy cytometer based on regularized optical flow algorithm

    Science.gov (United States)

    Xue, Liang; Vargas, Javier; Wang, Shouyu; Li, Zhenhua; Liu, Fei

    2015-09-01

    Cell detections and analysis are important in various fields, such as medical observations and disease diagnoses. In order to analyze the cell parameters as well as observe the samples directly, in this paper, we present an improved quantitative interferometric microscopy cytometer, which can monitor the quantitative phase distributions of bio-samples and realize cellular parameter statistics. The proposed system is able to recover the phase imaging of biological samples in the expanded field of view via a regularized optical flow demodulation algorithm. This algorithm reconstructs the phase distribution with high accuracy with only two interferograms acquired at different time points simplifying the scanning system. Additionally, the method is totally automatic, and therefore it is convenient for establishing a quantitative phase cytometer. Moreover, the phase retrieval approach is robust against noise and background. Excitingly, red blood cells are readily investigated with the quantitative interferometric microscopy cytometer system.

  12. A novel multi-walled carbon nanotube-based antibody conjugate for quantitative and semi-quantitative lateral flow assays.

    Science.gov (United States)

    Sun, Wenjuan; Hu, Xiaolong; Liu, Jia; Zhang, Yurong; Lu, Jianzhong; Zeng, Libo

    2017-10-01

    In this study, the multi-walled carbon nanotubes (MWCNTs) were applied in lateral flow strips (LFS) for semi-quantitative and quantitative assays. Firstly, the solubility of MWCNTs was improved using various surfactants to enhance their biocompatibility for practical application. The dispersed MWCNTs were conjugated with the methamphetamine (MET) antibody in a non-covalent manner and then manufactured into the LFS for the quantitative detection of MET. The MWCNTs-based lateral flow assay (MWCNTs-LFA) exhibited an excellent linear relationship between the values of test line and MET when its concentration ranges from 62.5 to 1500 ng/mL. The sensitivity of the LFS was evaluated by conjugating MWCNTs with HCG antibody and the MWCNTs conjugated method is 10 times more sensitive than the one conjugated with classical colloidal gold nanoparticles. Taken together, our data demonstrate that MWCNTs-LFA is a more sensitive and reliable assay for semi-quantitative and quantitative detection which can be used in forensic analysis.

  13. Simultaneous separation and quantitative determination of monosaccharides, uronic acids, and aldonic acids by high performance anion-exchange chromatography coupled with pulsed amperometric detection in corn stover prehydrolysates

    Directory of Open Access Journals (Sweden)

    Xing Wang

    2012-11-01

    Full Text Available A method for simultaneous separation and quantitative determination of arabinose, galactose, glucose, xylose, xylonic acid, gluconic acid, galacturonic acid, and glucuronic acid was developed by using high performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD. The separation was performed on a CarboPacTM PA-10 column (250 mm × 2 mm with a various gradient elution of NaOH-NaOAc solution as the mobile phase. The calibration curves showed good linearity (R2 ≥ 0.9993 for the monosaccharides, uronic acids, and aldonic acids in the range of 0.1 to 12.5 mg/L. The detection limits (LODs and the quantification limits (LOQs were 4.91 to 18.75 μg/L and 16.36 to 62.50 μg/L, respectively. Relative standard deviations (RSDs of the retention times and peak areas for the seven consecutive determinations of an unknown amount of mixture were 0.15% to 0.44% and 0.22% to 2.31%, respectively. The established method was used to separate and determine four monosaccharides, two uronic acids, and two aldonic acids in the prehydrolysate from dilute acid steam-exploded corn stover within 21 min. The spiked recoveries of monosaccharides, uronic acids, and aldonic acids ranged from 91.25% to 108.81%, with RSDs (n=3 of 0.04% ~ 6.07%. This method was applied to evaluate the quantitative variation of sugar and sugar acid content in biomass prehydrolysates.

  14. A monoclonal antibody-based VZV glycoprotein E quantitative assay and its application on antigen quantitation in VZV vaccine.

    Science.gov (United States)

    Liu, Jian; Zhu, Rui; Ye, Xiangzhong; Yang, Lianwei; Wang, Yongmei; Huang, Yanying; Wu, Jun; Wang, Wei; Ye, Jianghui; Li, Yimin; Zhao, Qinjian; Zhu, Hua; Cheng, Tong; Xia, Ningshao

    2015-06-01

    Varicella-zoster virus (VZV) is a highly infectious agent that causes varicella and herpes zoster (HZ), which may be associated with severe neuralgia. Vaccination is the most effective way to reduce the burden of the diseases. VZV glycoprotein E (gE) is the major and most immunogenic membrane protein that plays important roles in vaccine efficacy. A quantitative assay for gE content is desirable for the VZV vaccine process monitoring and product analysis. In this study, 70 monoclonal antibodies (mAbs) were obtained after immunizing mice with purified recombinant gE (rgE). The collection of mAbs was well-characterized, and a pair of high-affinity neutralization antibodies (capture mAb 4A2 and detection mAb 4H10) was selected to establish a specific and sensitive sandwich enzyme-linked immunosorbent assay (ELISA) to quantify the native and recombinant gE. The detection limit of this assay was found to be 1.95 ng/mL. Furthermore, a reasonably good correlation between the gE content (as measured by the mAb-based quantitative ELISA) and the virus titer (as measured by the "gold standard" plaque assay) was observed when both assays were performed for tracking the kinetics of virus growth during cell culture. A total of 16 batches of lyophilized VZV vaccine were tested using the newly developed quantitative ELISA and classical plaque assay, demonstrating reasonably good correlation between gE content and virus titer. Therefore, this mAb-based gE quantitative assay serves as a rapid, stable, and sensitive method for monitoring viral antigen content, one additional quantitative method for VZV vaccine process and product characterization. This quantitative ELISA may also serve as a complementary method for virus titering.

  15. Fermented probiotic beverages based on acid whey

    Directory of Open Access Journals (Sweden)

    Katarzyna Skryplonek

    2015-12-01

    Full Text Available Background. Production of fermented probiotic beverages can be a good method for acid whey usage. The obtained products combine a high nutritional value of whey with health benefits claimed for probiotic bac- teria. The aim of the study was to define quality properties of beverages based on fresh acid whey and milk with addition of buttermilk powder or sweet whey powder. Material and methods. Samples were inoculated with two strains of commercial probiotic cultures: Lac- tobacillus acidophilus La-5 or Bifidobacterium animalis Bb-12. After fermentation, samples were stored at refrigerated conditions. After 1, 4, 7, 14 and 21 days sensory characteristics, hardness, acetaldehyde content, titratable acidity, pH acidity and count of bacteria cells were evaluated. Results. Throughout all storage period, the number of bacteria was higher than 8 log cfu/ml in the all sam- ples. Beverages with La-5 strain had higher hardness and acidity, whilst samples with Bb-12 contained more acetaldehyde. Samples with buttermilk powder had better sensory properties than with sweet whey powder. Conclusions. Obtained products made of acid whey combined with milk and fortified with buttermilk pow- der or sweet whey powder, are good medium for growth and survival of examined probiotic bacteria strains. The level of bacteria was sufficient to provide health benefits to consumers.

  16. Glycine/Glycolic acid based copolymers

    NARCIS (Netherlands)

    in 't Veld, P.J.A.; in 't Veld, Peter J.A.; Shen, Zheng-Rong; Shen, Z.; Takens, Gijsbert A.J.; Takens, G.A.J.; Dijkstra, Pieter J.; Feijen, Jan

    1994-01-01

    Glycine/glycolic acid based biodegradable copolymers have been prepared by ring-opening homopolymerization of morpholine-2,5-dione, and ring-opening copolymerization of morpholine-2,5-dione and glycolide. The homopolymerization of morpholine-2,5-dione was carried out in the melt at 200°C for 3 min

  17. 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…

  18. The Magic Sign: Acids, Bases, and Indicators.

    Science.gov (United States)

    Phillips, Donald B.

    1986-01-01

    Presents an approach that is used to introduce elementary and junior high students to a series of activities that will provide concrete experiences with acids, bases, and indicators. Provides instructions and listings of needed solutions and materials for developing this "magic sign" device. Includes background information and several…

  19. 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…

  20. Glycine/Glycolic acid based copolymers

    NARCIS (Netherlands)

    Veld, in 't Peter J.A.; Shen, Zheng-Rong; Takens, Gijsbert A.J.; Dijkstra, Pieter J.; Feijen, Jan

    1994-01-01

    Glycine/glycolic acid based biodegradable copolymers have been prepared by ring-opening homopolymerization of morpholine-2,5-dione, and ring-opening copolymerization of morpholine-2,5-dione and glycolide. The homopolymerization of morpholine-2,5-dione was carried out in the melt at 200°C for 3 min u

  1. Quantitative analysis of glycerol in dicarboxylic acid-rich cutins provides insights into Arabidopsis cutin structure.

    Science.gov (United States)

    Yang, Weili; Pollard, Mike; Li-Beisson, Yonghua; Ohlrogge, John

    2016-10-01

    Cutin is an extracellular lipid polymer that contributes to protective cuticle barrier functions against biotic and abiotic stresses in land plants. Glycerol has been reported as a component of cutin, contributing up to 14% by weight of total released monomers. Previous studies using partial hydrolysis of cuticle-enriched preparations established the presence of oligomers with glycerol-aliphatic ester links. Furthermore, glycerol-3-phosphate 2-O-acyltransferases (sn-2-GPATs) are essential for cutin biosynthesis. However, precise roles of glycerol in cutin assembly and structure remain uncertain. Here, a stable isotope-dilution assay was developed for the quantitative analysis of glycerol by GC/MS of triacetin with simultaneous determination of aliphatic monomers. To provide clues about the role of glycerol in dicarboxylic acid (DCA)-rich cutins, this methodology was applied to compare wild-type (WT) Arabidopsis cutin with a series of mutants that are defective in cutin synthesis. The molar ratio of glycerol to total DCAs in WT cutins was 2:1. Even when allowing for a small additional contribution from hydroxy fatty acids, this is a substantially higher glycerol to aliphatic monomer ratio than previously reported for any cutin. Glycerol content was strongly reduced in both stem and leaf cutin from all Arabidopsis mutants analyzed (gpat4/gpat8, att1-2 and lacs2-3). In addition, the molar reduction of glycerol was proportional to the molar reduction of total DCAs. These results suggest "glycerol-DCA-glycerol" may be the dominant motif in DCA-rich cutins. The ramifications and caveats for this hypothesis are presented.

  2. Quantitative analysis of aberrant fatty acid composition of zebrafish hepatic lipids induced by organochlorine pesticide using stable isotope-coded transmethylation and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Zhong, Hongying; Dong, Linjie; Dong, Qingjian; Ke, Changshu; Fu, Jieying; Wang, Xiaoli; Liu, Cong; Dai, Ling

    2012-07-01

    Organochlorine pesticides have been extensively used worldwide for agricultural purposes. Due to their resistance to metabolism, a major public health concern has been raised. Aberrant hepatic lipid composition has been a hallmark of many liver diseases associated with exposure to various toxins and chemicals. And thus lots of efforts have been focused on the development of analytical techniques that can rapidly and quantitatively determine the changes in fatty acid composition of hepatic lipids. In this work, changes in fatty acid composition of hepatic lipids in response to DDT (dichlorodiphenyltrichloroethane) exposure were quantitatively analyzed by a gas chromatography-mass spectrometric approach based on stable isotope-coded transmethylation. It has been quantitatively demonstrated that polyunsaturated fatty acids including C20:3n3, C20:4n6, and C22:6n3 decrease in response to DDT exposure. However, saturated long chain fatty acids including C16:0, C18:0, as well as monounsaturated long chain fatty acid C18:1n9 consistently increase in a DDT-concentration-dependent manner. In particular, much higher changes in the level of hepatic C16:0 and C18:0 for male fish were observed than that for female fish. These experimental results are in accordance with qualitative histopathological analysis that revealed liver morphological alterations. The stable isotope-coded mass spectrometric approach provides a reliable means for investigating hepatotoxicity associated with fatty acid synthesis, desaturation, mitochondrial beta-oxidation, and lipid mobilization. It should be useful in elucidation of hepatotoxic mechanisms and safety assessment of environmental toxins.

  3. Absolute quantification for benzoic acid in processed foods using quantitative proton nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Ohtsuki, Takashi; Sato, Kyoko; Sugimoto, Naoki; Akiyama, Hiroshi; Kawamura, Yoko

    2012-09-15

    The absolute quantification method of benzoic acid (BA) in processed foods using solvent extraction and quantitative proton nuclear magnetic resonance spectroscopy was developed and validated. BA levels were determined using proton signals (δ(H) 7.53 and 7.98) referenced to 2-dimethyl-2-silapentane-5-sulfonate-d(6) sodium salt (DSS-d(6)) after simple solvent extraction from processed foods. All recoveries from several kinds of processed foods, spiked at their specified maximum Japanese usage levels (0.6-2.5 g kg(-1)) and at 0.13 g kg(-1) and 0.063 g kg(-1), were greater than 80%. The limit of quantification was confirmed as 0.063 g kg(-1) in processed foods, which was sufficiently low for the purposes of monitoring BA. The accuracy of the proposed method is equivalent to the conventional method using steam-distillation extraction and high-performance liquid chromatography. The proposed method was both rapid and simple. Moreover, it provided International System of Units traceability without the need for authentic analyte standards. Therefore, the proposed method is a useful and practical tool for determining BA levels in processed foods.

  4. Absolute quantitative analysis for sorbic acid in processed foods using proton nuclear magnetic resonance spectroscopy.

    Science.gov (United States)

    Ohtsuki, Takashi; Sato, Kyoko; Sugimoto, Naoki; Akiyama, Hiroshi; Kawamura, Yoko

    2012-07-13

    An analytical method using solvent extraction and quantitative proton nuclear magnetic resonance (qHNMR) spectroscopy was applied and validated for the absolute quantification of sorbic acid (SA) in processed foods. The proposed method showed good linearity. The recoveries for samples spiked at the maximum usage level specified for food in Japan and at 0.13 g kg(-1) (beverage: 0.013 g kg(-1)) were larger than 80%, whereas those for samples spiked at 0.063 g kg(-1) (beverage: 0.0063 g kg(-1)) were between 56.9 and 83.5%. The limit of quantification was 0.063 g kg(-1) for foods (and 0.0063 g kg(-1) for beverages containing Lactobacillus species). Analysis of the SA content of commercial processed foods revealed quantities equal to or greater than those measured using conventional steam-distillation extraction and high-performance liquid chromatography quantification. The proposed method was rapid, simple, accurate, and precise, and provided International System of Units traceability without the need for authentic analyte standards. It could therefore be used as an alternative to the quantification of SA in processed foods using conventional method.

  5. Optimization and Quality Control of Automated Quantitative Mineralogy Analysis for Acid Rock Drainage Prediction

    Directory of Open Access Journals (Sweden)

    Robert Pooler

    2017-01-01

    Full Text Available Low ore-grade waste samples from the Codelco Andina mine that were analyzed in an environmental and mineralogical test program for acid rock drainage prediction, revealed inconsistencies between the quantitative mineralogical data (QEMSCAN® and the results of geochemical characterizations by atomic absorption spectroscopy (AAS, LECO® furnace, and sequential extractions. For the QEMSCAN® results, biases were observed in the proportions of pyrite and calcium sulfate minerals detected. An analysis of the results indicated that the problems observed were likely associated with polished section preparation. Therefore, six different sample preparation protocols were tested and evaluated using three samples from the previous study. One of the methods, which involved particle size reduction and transverse section preparation, was identified as having the greatest potential for correcting the errors observed in the mineralogical analyses. Further, the biases in the quantities of calcium sulfate minerals detected were reduced through the use of ethylene glycol as a polishing lubricant. It is recommended that the sample preparation methodology described in this study be used in order to accurately quantify percentages of pyrite and calcium sulfate minerals in environmental mineralogical studies which use automated mineralogical analysis.

  6. Identification of Quantitative Trait Loci for Phytic Acid Concentration in Maize Grain Under Two Nitrogen Conditions

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-chao; HUANG Ya-qun; MA Wen-qi; ZHOU Jin-feng; BIAN Fen-ru; CHEN Fan-jun; MI Guo-hua

    2013-01-01

    Phytic acid (PA) is the main storage form of phosphorus (P) in seeds. It can form insoluble complexes with microelements, thereby reducing their bioavailability for animals. Identification of quantitative trait loci (QTLs) associated with grain PA concentration (PAC) is essential to improve this trait without affecting other aspects of grain nutrition such as protein content. Using a recombinant inbred line (RIL) population, we mapped QTL for grain PAC, as well as grain nitrogen concentration (NC) and P concentration (PC) in maize under two N conditions in 2 yr. We detected six QTLs for PAC. The QTL for PAC on chromosome 4 (phi072-umc1276) was identified under both low-N and high-N treatments, and explained 13.2 and 15.4%of the phenotypic variance, respectively. We identified three QTLs for grain NC, none of which were in the same region as the QTLs for PAC. We identified two QTLs for PC in the low-N treatment, one of which (umc1710-umc2197) was in the same interval as the QTL for PAC under high-N conditions. These results suggested that grain PAC can be improved without affecting grain NC and inorganic PC.

  7. CANDU in-reactor quantitative visual-based inspection techniques

    Science.gov (United States)

    Rochefort, P. A.

    2009-02-01

    This paper describes two separate visual-based inspection procedures used at CANDU nuclear power generating stations. The techniques are quantitative in nature and are delivered and operated in highly radioactive environments with access that is restrictive, and in one case is submerged. Visual-based inspections at stations are typically qualitative in nature. For example a video system will be used to search for a missing component, inspect for a broken fixture, or locate areas of excessive corrosion in a pipe. In contrast, the methods described here are used to measure characteristic component dimensions that in one case ensure ongoing safe operation of the reactor and in the other support reactor refurbishment. CANDU reactors are Pressurized Heavy Water Reactors (PHWR). The reactor vessel is a horizontal cylindrical low-pressure calandria tank approximately 6 m in diameter and length, containing heavy water as a neutron moderator. Inside the calandria, 380 horizontal fuel channels (FC) are supported at each end by integral end-shields. Each FC holds 12 fuel bundles. The heavy water primary heat transport water flows through the FC pressure tube, removing the heat from the fuel bundles and delivering it to the steam generator. The general design of the reactor governs both the type of measurements that are required and the methods to perform the measurements. The first inspection procedure is a method to remotely measure the gap between FC and other in-core horizontal components. The technique involves delivering vertically a module with a high-radiation-resistant camera and lighting into the core of a shutdown but fuelled reactor. The measurement is done using a line-of-sight technique between the components. Compensation for image perspective and viewing elevation to the measurement is required. The second inspection procedure measures flaws within the reactor's end shield FC calandria tube rolled joint area. The FC calandria tube (the outer shell of the FC) is

  8. The Quantitative Analysis to Inferior Oil with Electronic Nose Based on Adaptive Multilayer Stochastic Resonance

    Directory of Open Access Journals (Sweden)

    Hong Men

    2011-09-01

    Full Text Available This study makes the three acryl glycerin polymers, oxidation three acryl glycerins, and low carbon number fatty acid as inferior oil feature index. Using double steady state stochastic resonance signal-to-noise ratio analysis methods make the quantitative analysis to inferior oil. This paper analyzes the stochastic resonance. Introduces the principle detection system structure based on adaptive multilayer stochastic resonance algorithm in inferior oil quantitativeanalysis; and make adaptive double stochastic resonance model and inferior oil as example, give the simulation and numerical analysis of this model of the system. The results show that the system can obtain more accurate quality the proportion of the inferior oil information. At the same time, this method can effectively solve the semiconductor gas sensors of the baseline drift problem. The method of stochastic resonance has a lot of application prospect in improving the system performance.

  9. Hepatitis C Virus RNA Real-Time Quantitative RT-PCR Method Based on a New Primer Design Strategy.

    Science.gov (United States)

    Chen, Lida; Li, Wenli; Zhang, Kuo; Zhang, Rui; Lu, Tian; Hao, Mingju; Jia, Tingting; Sun, Yu; Lin, Guigao; Wang, Lunan; Li, Jinming

    2016-01-01

    Viral nucleic acids are unstable when improperly collected, handled, and stored, resulting in decreased sensitivity of currently available commercial quantitative nucleic acid testing kits. Using known unstable hepatitis C virus RNA, we developed a quantitative RT-PCR method based on a new primer design strategy to reduce the impact of nucleic acid instability on nucleic acid testing. The performance of the method was evaluated for linearity, limit of detection, precision, specificity, and agreement with commercial hepatitis C virus assays. Its clinical application was compared to that of two commercial kits--Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) and Kehua. The quantitative RT-PCR method delivered a good performance, with a linearity of R(2) = 0.99, a total limit of detection (genotypes 1 to 6) of 42.6 IU/mL (95% CI, 32.84 to 67.76 IU/mL), a CV of 1.06% to 3.34%, a specificity of 100%, and a high concordance with the CAP/CTM assay (R(2) = 0.97), with a means ± SD value of -0.06 ± 1.96 log IU/mL (range, -0.38 to 0.25 log IU/mL). The method was superior to commercial assays in detecting unstable hepatitis C virus RNA (P quantitative RT-PCR method can effectively eliminate the influence of RNA instability on nucleic acid testing. The principle of primer design strategy may be applied to the detection of other RNA or DNA viruses.

  10. Mapping the Hydropathy of Amino Acids Based on Their Local Solvation Structure

    KAUST Repository

    Bonella, S.

    2014-06-19

    In spite of its relevant biological role, no general consensus exists on the quantitative characterization of amino acid\\'s hydropathy. In particular, many hydrophobicity scales exist, often producing quite different rankings for the amino acids. To make progress toward a systematic classification, we analyze amino acids\\' hydropathy based on the orientation of water molecules at a given distance from them as computed from molecular dynamics simulations. In contrast with what is usually done, we argue that assigning a single number is not enough to characterize the properties of an amino acid, in particular when both hydrophobic and hydrophilic regions are present in a residue. Instead we show that appropriately defined conditional probability densities can be used to map the hydrophilic and hydrophobic groups on the amino acids with greater detail than possible with other available methods. Three indicators are then defined based on the features of these probabilities to quantify the specific hydrophobicity and hydrophilicity of each amino acid. The characterization that we propose can be used to understand some of the ambiguities in the ranking of amino acids in the current scales. The quantitative indicators can also be used in combination with standard bioinformatics tools to predict the location of transmembrane regions of proteins. The method is sensitive to the specific environment of the amino acids and can be applied to unnatural and modified amino acids, as well as to other small organic molecules. © 2014 American Chemical Society.

  11. The solubilization of fatty acids in systems based on block copolymers and nonionic surfactants

    Science.gov (United States)

    Mirgorodskaya, A. B.; Yatskevich, E. I.; Zakharova, L. Ya.

    2010-12-01

    The solubilizing action of micellar, microemulsion, and polymer-colloid systems formed on the basis of biologically compatible amphiphilic polymers and nonionic surfactants on capric, lauric, palmitic, and stearic acids was characterized quantitatively. Systems based on micelle forming oxyethyl compounds increased the solubility of fatty acids by more than an order of magnitude. Acid molecules incorporated into micelles increased their size and caused structural changes. Solubilization was accompanied by complete or partial destruction of intrinsic acid associates and an increase in their p K a by 1.5-2 units compared with water.

  12. Aplicação de extratos brutos de flores de quaresmeira e azaléia e da casca de feijão preto em volumetria ácido-base. Um experimento para cursos de análise quantitativa Application of crude extracts of Tibouchina granulosa and Rhododendron sinsii flowers and Phasealus vulgares grains skin in acid - base titration. A quantitative laboratory experiment

    Directory of Open Access Journals (Sweden)

    Márlon Herbert Flora Barbosa Soares

    2001-06-01

    Full Text Available Crude extract of Tibouchina granulosa, Rhododendron simsii and Phaseolus vulgaris L. were prepared and used as alternative indicators in quantitative analysis teaching in standardization of NaOH solutions and in the determination of acetic acid contents in vinegar. Effect of using such natural extracts as indicators was very attractive to the students and the quantitative results were compared with conventional indicators with good agreement. Concepts of data statistics can successfully be discussed using the interest revived by the use of natural indicators.

  13. Quantitative amino acid profiling and stable isotopically labeled amino acid tracer enrichment used for in vivo human systemic and tissue kinetics measurements.

    Science.gov (United States)

    Bornø, Andreas; van Hall, Gerrit

    2014-03-01

    An important area within clinical functional metabolomics is in vivo amino acid metabolism and protein turnover measurements for which accurate amino acid concentrations and stable isotopically labeled amino acid enrichments are mandatory not the least when tissue metabolomics is determined. The present study describes a new sensitive liquid chromatography tandem mass-spectrometry method quantifying 20 amino acids and their tracer(s) ([ring-(13)C6]/D5Phenylalanine) in human plasma and skeletal muscle specimens. Before analysis amino acids were extracted and purified via deprotonization/ion exchange, derivatized using a phenylisothiocyanate reagent and each amino acid was quantitated with its own stable isotopically labeled internal standard (uniformly labeled-(13)C/(15)N). The method was validated according to general recommendations for chromatographic analytical methods. The calibration curve correlations for amino acids were on average; r(2)=0.998. Interday accuracy for amino acids determined in spiked plasma was on average 97.3% and the coefficient of variation (CV) was 2.6%. The ([ring-(13)C6]/D5Phenylalanine) enrichment CV's for machine reproducibility in muscle tissue fluid and plasma were 4.4 and 0.8%, and the interday variability was 3.4% and the recovery was 90.5%, respectively. In conclusion, we have developed and validated a method for quantitative amino acid profiling that meets the requirements for systemic and tissue human in vivo amino acid and protein turnover kinetics measurements. Moreover, citrulline, ornithine, π-methyl-histidine, τ-methyl-l-histidine, hydroxy-proline and carnitine were analysed but when similar precision and accuray are required an additional stable istopically labeled internal standard for these meatablites should be be added.

  14. A Quantitative ADME-base Tool for Exploring Human ...

    Science.gov (United States)

    Exposure to a wide range of chemicals through our daily habits and routines is ubiquitous and largely unavoidable within modern society. The potential for human exposure, however, has not been quantified for the vast majority of chemicals with wide commercial use. Creative advances in exposure science are needed to support efficient and effective evaluation and management of chemical risks, particularly for chemicals in consumer products. The U.S. Environmental Protection Agency Office of Research and Development is developing, or collaborating in the development of, scientifically-defensible methods for making quantitative or semi-quantitative exposure predictions. The Exposure Prioritization (Ex Priori) model is a simplified, quantitative visual dashboard that provides a rank-ordered internalized dose metric to simultaneously explore exposures across chemical space (not chemical by chemical). Diverse data streams are integrated within the interface such that different exposure scenarios for “individual,” “population,” or “professional” time-use profiles can be interchanged to tailor exposure and quantitatively explore multi-chemical signatures of exposure, internalized dose (uptake), body burden, and elimination. Ex Priori has been designed as an adaptable systems framework that synthesizes knowledge from various domains and is amenable to new knowledge/information. As such, it algorithmically captures the totality of exposure across pathways. It

  15. 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.

  16. Development of quantitative structure-metabolism (QSMR) relationships for substituted anilines based on computational chemistry.

    Science.gov (United States)

    Athersuch, Toby J; Wilson, Ian D; Keun, Hector C; Lindon, John C

    2013-09-01

    A novel stepwise classification approach for predicting the metabolic fate of substituted anilines, based on calculated physicochemical parameters of the parent anilines, was developed. Based on multivariate pattern recognition methods (PLS-DA or soft independent modelling of class analogy [SIMCA]), these models allowed prediction of N-acetylation and subsequent N-oxanilic acid formation. These classification methods provided an improved classification success when compared with existing quantitative structure-metabolism relationship models for substituted anilines. Modelling the physicochemical properties of the N-acetylated compounds was considered as an addition to the stepwise model. Inclusion of parameters describing the N-acetyl moiety had little effect on the predictive ability of a stepwise parent to N-acetyl to N-oxanilic acid PLS-DA model, and had a negative impact on that of SIMCA models. This was attributed to the relatively small contribution to the total parameter variance caused by differences arising as a result of N-acetylation compared to the contribution made by the substituent effects. Calculation of physicochemical properties incorporating the effect of solvation using ab initio methods improved the classification model in terms of both the visual separation in multivariate projections and prediction accuracy.

  17. Pre-harvest foliar application of humic acid, salicylic acid and calcium chloride to increase quantitative and qualitative traits of Lilium longiflorum cut flowers

    Directory of Open Access Journals (Sweden)

    S.N. Mortazavi

    2015-11-01

    Full Text Available Lily (Lilium longiflorum L. is one of the most important potted flowers, which is used largely as cut flower. An experiment, arranged as a factorial besed on completely randomized dasign with three replications, was carried out to evaluate the effects of pre-harvest foliar application of humic acid, salicylic acid and calcium chloride on quality and longevity of lilium cut flowers. Treatments  included humic acid as factor a (0, 100, 500 and 1000 mg/L and three salicylic acid concentrations (0, 150 and 200 mg/L and two calcium chloride concentrations (300 and 600 mg/L as factor b, which were sprayed at two stages before harvesting the flowers. Results showed that treating the plants with 500 mg/L humic acid increased water uptake and chlorophyll a content and decreased number of fallen florets. Application of 1000 mg/L humic acid increased total chlorophyll content. Pre-harvest treatment of flowers with 600 mg/L calcium chloride increased florets’ diameter, relative water content, chlorophyll b content and shelf life, as compared to other concentrations and different salicylic concentrations. In this research, the highest shelf life was observed for flowers sprayed with 1000 mg/L humic acid and 300 mg/L calcium chloride. Therefore, pre-harvest foliar application of humic acid, salicylic acid and calcium chloride could have positive effects on quantitative and qualitative traits of lilium cut flowers.

  18. [Research on the Quantitative Analysis for In-Situ Detection of Acid Radical Ions Using Laser Raman Spectroscopy].

    Science.gov (United States)

    Chen, Jing; Li, Ying; Du, Zeng-feng; Gu, Yan-hong; Guo, Jin-jia

    2015-09-01

    Laser Raman spectroscopy as an in situ analytical technology can enable detailed investigation of the ocean environment. It is necessary to set up a quantitative analysis method based on laser Raman spectroscopy to understand the marine status in situ. In the laboratory investigations, varied concentration of HCO3(-), SO4(2-) and coastal waters of Qingdao are taken as the samples, operating 532 nm of laser, using fiber optic probes to simulate detection mode in situ. Raman spectra are analyzed using the method of internal standard normalization, multiple linear regression (MLR), general Partial Least Squares (PLS) and PLS based on dominant factor respectively in data processing. It was found that correlation coefficients of calibration curves are not high in internal standard normalization method and predicted relative errors on the prepared samples are much high, so internal standard normalization method cannot be effectively used in the quantitative analysis of HCO3(-), SO4(2-) in the water. And with the multiple linear regression, the analysis accuracy was improved effectively. The calibration curve of PLS based on dominant factor showed that the SO4(2-) and HCO3(-) of pre-made solution with correlation coefficient R2 of 0.990 and 0.916 respectively. The 30 mmol · L(-1) of SO4(2-) and 20 mmol · L(-1) of HCO3(-) in two target samples were determined with the relative errors lower than 3.262% and 5.267% respectively. SO4(2-) in the coastal waters as the research object was analyzed by above-mentioned methods, comparing with 28.01 mmol · L(-1) by ion chromatography. It was demonstrated that PLS based on dominant factor method is superior to the rest of the three analysis methods, which can be used in situ calibration, with the mean relative error about 1.128%. All the results show that analysis accuracy would be improved by the PLS based on dominant factor method to predict concentration of acid radical ions.

  19. Quantitative Determination of Fatty Acids in Marine Fish and Shellfish from Warm Water of Straits of Malacca for Nutraceutical Purposes

    Directory of Open Access Journals (Sweden)

    Nurnadia Abd Aziz

    2013-01-01

    Full Text Available This study was conducted to quantitatively determine the fatty acid contents of 20 species of marine fish and four species of shellfish from Straits of Malacca. Most samples contained fairly high amounts of polyunsaturated fatty acids (PUFAs, especially alpha-linolenic acid (ALA, C18:3 n3, eicosapentaenoic acid (EPA, C20:5 n3, and docosahexaenoic acid (DHA, C22:6 n3. Longtail shad, yellowstripe scad, and moonfish contained significantly higher (P<0.05 amounts of eicosapentaenoic acid (EPA, docosahexaenoic acid (DHA, and alpha-linolenic acid (ALA, respectively. Meanwhile, fringescale sardinella, malabar red snapper, black pomfret, Japanese threadfin bream, giant seaperch, and sixbar grouper showed considerably high content (537.2–944.1 mg/100g wet sample of desirable omega-3 fatty acids. The polyunsaturated-fatty-acids/saturated-fatty-acids (P/S ratios for most samples were higher than that of Menhaden oil (P/S=0.58, a recommended PUFA supplement which may help to lower blood pressure. Yellowstripe scad (highest DHA, ω-3/ω-6=6.4, P/S=1.7, moonfish (highest ALA, ω-3/ω-6=1.9, P/S=1.0, and longtail shad (highest EPA, ω-3/ω-6=0.8, P/S=0.4 were the samples with an outstandingly desirable overall composition of fatty acids. Overall, the marine fish and shellfish from the area contained good composition of fatty acids which offer health benefits and may be used for nutraceutical purposes in the future.

  20. Quantitative Determination of Fatty Acids in Marine Fish and Shellfish from Warm Water of Straits of Malacca for Nutraceutical Purposes

    Science.gov (United States)

    Abd Aziz, Nurnadia; Azlan, Azrina; Ismail, Amin; Mohd Alinafiah, Suryati; Razman, Muhammad Rizal

    2013-01-01

    This study was conducted to quantitatively determine the fatty acid contents of 20 species of marine fish and four species of shellfish from Straits of Malacca. Most samples contained fairly high amounts of polyunsaturated fatty acids (PUFAs), especially alpha-linolenic acid (ALA, C18:3 n3), eicosapentaenoic acid (EPA, C20:5 n3), and docosahexaenoic acid (DHA, C22:6 n3). Longtail shad, yellowstripe scad, and moonfish contained significantly higher (P < 0.05) amounts of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and alpha-linolenic acid (ALA), respectively. Meanwhile, fringescale sardinella, malabar red snapper, black pomfret, Japanese threadfin bream, giant seaperch, and sixbar grouper showed considerably high content (537.2–944.1 mg/100g wet sample) of desirable omega-3 fatty acids. The polyunsaturated-fatty-acids/saturated-fatty-acids (P/S) ratios for most samples were higher than that of Menhaden oil (P/S = 0.58), a recommended PUFA supplement which may help to lower blood pressure. Yellowstripe scad (highest DHA, ω − 3/ω − 6 = 6.4, P/S = 1.7), moonfish (highest ALA, ω − 3/ω − 6 = 1.9, P/S = 1.0), and longtail shad (highest EPA, ω − 3/ω − 6 = 0.8, P/S = 0.4) were the samples with an outstandingly desirable overall composition of fatty acids. Overall, the marine fish and shellfish from the area contained good composition of fatty acids which offer health benefits and may be used for nutraceutical purposes in the future. PMID:23509703

  1. Stable Isotope Labeling by Amino Acids in Cell Culture (SILAC) Applied to Quantitative Proteomics of Bacillus subtilis

    DEFF Research Database (Denmark)

    Soufi, Boumediene; Kumar, C.; Gnad, F.

    2010-01-01

    We applied stable isotope labeling by amino acids in cell culture (SILAC) to large-scale quantitative proteomics analyses of the model bacterium Bacillus subtilis in two physiological conditions: growth on succinate and growth under phosphate starvation. Using a B. subtilis strain auxotrophic...... of the most comprehensive quantitative proteomics studies in bacteria, covering more than 75% of the B. subtilis genes expressed in the log phase of growth. Furthermore, we detect and quantify dynamics of 35 Ser/Thr/Tyr phosphorylation sites under growth on succinate, and 10 phosphorylation sites under...

  2. Absolute quantitative analysis for sorbic acid in processed foods using proton nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ohtsuki, Takashi, E-mail: ohtsuki@nihs.go.jp [National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Sato, Kyoko; Sugimoto, Naoki; Akiyama, Hiroshi; Kawamura, Yoko [National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan)

    2012-07-13

    Highlights: Black-Right-Pointing-Pointer A method using qHNMR was applied and validated to determine SA in processed foods. Black-Right-Pointing-Pointer This method has good accuracy, precision, selectiveness, and linearity. Black-Right-Pointing-Pointer The proposed method is more rapid and simple than the conventional method. Black-Right-Pointing-Pointer We found that the proposed method is reliable for the accurate determination of SA. Black-Right-Pointing-Pointer This method can be used for the monitoring of SA in processed foods. - Abstract: An analytical method using solvent extraction and quantitative proton nuclear magnetic resonance (qHNMR) spectroscopy was applied and validated for the absolute quantification of sorbic acid (SA) in processed foods. The proposed method showed good linearity. The recoveries for samples spiked at the maximum usage level specified for food in Japan and at 0.13 g kg{sup -1} (beverage: 0.013 g kg{sup -1}) were larger than 80%, whereas those for samples spiked at 0.063 g kg{sup -1} (beverage: 0.0063 g kg{sup -1}) were between 56.9 and 83.5%. The limit of quantification was 0.063 g kg{sup -1} for foods (and 0.0063 g kg{sup -1} for beverages containing Lactobacillus species). Analysis of the SA content of commercial processed foods revealed quantities equal to or greater than those measured using conventional steam-distillation extraction and high-performance liquid chromatography quantification. The proposed method was rapid, simple, accurate, and precise, and provided International System of Units traceability without the need for authentic analyte standards. It could therefore be used as an alternative to the quantification of SA in processed foods using conventional method.

  3. Acid-base analysis: a critique of the Stewart and bicarbonate-centered approaches.

    Science.gov (United States)

    Kurtz, Ira; Kraut, Jeffrey; Ornekian, Vahram; Nguyen, Minhtri K

    2008-05-01

    When approaching the analysis of disorders of acid-base balance, physical chemists, physiologists, and clinicians, tend to focus on different aspects of the relevant phenomenology. The physical chemist focuses on a quantitative understanding of proton hydration and aqueous proton transfer reactions that alter the acidity of a given solution. The physiologist focuses on molecular, cellular, and whole organ transport processes that modulate the acidity of a given body fluid compartment. The clinician emphasizes the diagnosis, clinical causes, and most appropriate treatment of acid-base disturbances. Historically, two different conceptual frameworks have evolved among clinicians and physiologists for interpreting acid-base phenomena. The traditional or bicarbonate-centered framework relies quantitatively on the Henderson-Hasselbalch equation, whereas the Stewart or strong ion approach utilizes either the original Stewart equation or its simplified version derived by Constable. In this review, the concepts underlying the bicarbonate-centered and Stewart formulations are analyzed in detail, emphasizing the differences in how each approach characterizes acid-base phenomenology at the molecular level, tissue level, and in the clinical realm. A quantitative comparison of the equations that are currently used in the literature to calculate H(+) concentration ([H(+)]) is included to clear up some of the misconceptions that currently exist in this area. Our analysis demonstrates that while the principle of electroneutrality plays a central role in the strong ion formulation, electroneutrality mechanistically does not dictate a specific [H(+)], and the strong ion and bicarbonate-centered approaches are quantitatively identical even in the presence of nonbicarbonate buffers. Finally, our analysis indicates that the bicarbonate-centered approach utilizing the Henderson-Hasselbalch equation is a mechanistic formulation that reflects the underlying acid-base phenomenology.

  4. Algerian mint species: high performance thin layer chromatography quantitative determination of rosmarinic acid and in vitro inhibitory effects on linoleic acid peroxidation

    Directory of Open Access Journals (Sweden)

    Brahmi Fatiha

    2014-12-01

    Full Text Available Objective: To determine the quantitative paremeters of rosmarinic acid in Algerian mints, Mentha spicata L. (M. spicata, Mentha pulegium L. and Mentha rotundifolia (L. Huds by high performance thin layer chromatography (HPTLC-densitometric method and screen the effects of these plant extracts on linoleic acid peroxidation. Methods: The analyses were performed on HPTLC silica gel 60 F254 plates with chloroform: acetone: formic acid (75:16.5:8.5, v/v as the mobile phase. Rosmarinic acid was determined in UV at 365 nm and fluorescence at λexc 325 nm with a 550 nm filter, respectively. The effects of plants extracts on linoleic acid peroxidation were measured by an indirect in vitro colorimetric method. Results: Chromatographic resolution permitted reliable quantification in both measurement modes and calibration curves were linear in a range of 150-1 000 ng/spot. M. spicata was found to contain significantly higher concentrations of rosmarinic acid. The densitometric quantification allowed the analysis of many samples in a short time with reasonable precision (total precision for Mentha spp extracts, 5.1% and 5.8% for UV and fluorescence detection, respectively. The HPTLC data, allied to assays of linoleic acid peroxidation prevention, suggested the potential of M. spicata (52% Trolox® equivalents as a natural source for inhibitors of lipid peroxidation. Conclusions: Densitometry can be used for routine determination and quality control of rosmarinic acid in herbal and formulations containing Mentha species.

  5. Algerian mint species:high performance thin layer chromatography quantitative determination of rosmarinic acid and in vitro inhibitory effects on linoleic acid peroxidation

    Institute of Scientific and Technical Information of China (English)

    Brahmi Fatiha; Madani Khodir; Stvigny Caroline; Chibane Mohamed; Duez Pierre

    2014-01-01

    Objective: To determine the quantitative paremeters of rosmarinic acid in Algerian mints,Mentha spicata L. (M. spicata), Mentha pulegium L. and Mentha rotundifolia (L.) Huds by high performance thin layer chromatography (HPTLC)-densitometric method and screen the effects of these plant extracts on linoleic acid peroxidation.Methods:The analyses were performed on HPTLC silica gel 60 F254 plates with chloroform:acetone: formic acid (75:16.5:8.5, v/v) as the mobile phase. Rosmarinic acid was determined in UV at 365 nm and fluorescence at λexc 325 nm with a 550 nm filter, respectively. The effects of plants extracts on linoleic acid peroxidation were measured by an indirect in vitro colorimetric method.Results:Chromatographic resolution permitted reliable quantification in both measurement modes and calibration curves were linear in a range of 150-1000 ng/spot. M. spicata was found to contain significantly higher concentrations of rosmarinic acid. The densitometric quantification allowed the analysis of many samples in a short time with reasonable precision (total precision for Mentha spp extracts, 5.1% and 5.8% for UV and fluorescence detection, respectively). The HPTLC data, allied to assays of linoleic acid peroxidation prevention, suggested the potential of M. spicata (52% Trolox®equivalents) as a natural source for inhibitors of lipid peroxidation.Conclusions:Densitometry can be used for routine determination and quality control of rosmarinic acid in herbal and formulations containing Mentha species.

  6. Hyperspectral analysis for qualitative and quantitative features related to acid mine drainage at a remediated open-pit mine

    Science.gov (United States)

    Davies, G.; Calvin, W. M.

    2015-12-01

    The exposure of pyrite to oxygen and water in mine waste environments is known to generate acidity and the accumulation of secondary iron minerals. Sulfates and secondary iron minerals associated with acid mine drainage (AMD) exhibit diverse spectral properties in the ultraviolet, visible and near-infrared regions of the electromagnetic spectrum. The use of hyperspectral imagery for identification of AMD mineralogy and contamination has been well studied. Fewer studies have examined the impacts of hydrologic variations on mapping AMD or the unique spectral signatures of mine waters. Open-pit mine lakes are an additional environmental hazard which have not been widely studied using imaging spectroscopy. A better understanding of AMD variation related to climate fluctuations and the spectral signatures of contaminated surface waters will aid future assessments of environmental contamination. This study examined the ability of multi-season airborne hyperspectral data to identify the geochemical evolution of substances and contaminant patterns at the Leviathan Mine Superfund site. The mine is located 24 miles southeast of Lake Tahoe and contains remnant tailings piles and several AMD collection ponds. The objectives were to 1) distinguish temporal changes in mineralogy at a the remediated open-pit sulfur mine, 2) identify the absorption features of mine affected waters, and 3) quantitatively link water spectra to known dissolved iron concentrations. Images from NASA's AVIRIS instrument were collected in the spring, summer, and fall seasons for two consecutive years at Leviathan (HyspIRI campaign). Images had a spatial resolution of 15 meters at nadir. Ground-based surveys using the ASD FieldSpecPro spectrometer and laboratory spectral and chemical analysis complemented the remote sensing data. Temporal changes in surface mineralogy were difficult to distinguish. However, seasonal changes in pond water quality were identified. Dissolved ferric iron and chlorophyll

  7. Determining the best extractant and extraction conditions for fulvic acid through qualitative and quantitative analysis of vermicompost

    Directory of Open Access Journals (Sweden)

    Omid Shabnani Moghadam

    2015-06-01

    Full Text Available Fulvic acid is a natural tampon and an appropriate chelating agent that has high ion-exchange ability and increasing absorption of minerals in plants. This paper examined the effects of extractants (sodium hydroxide, sodium polyphosphate, urea and EDTA and the extraction time (1, 7 and 9 days on the physicochemical properties of vermicompost-produced fulvic acid. Finally, various methods were compared to the universal method of humic substances. Different qualitative and quantitative analysis such as detecting the functional groups (FTIR, measurement of functional groups, spectrophotometric ratios and humification indices were carried out on fulvic acid. Results showed that the highest and lowest amounts of fulvic acid were extracted by the sodium hydroxide and urea, respectively. Various extractants made negligible changes in the type and quality of the Fulvic acid functional groups. Results indicated that sodium hydroxide was the best extractant and the minimum amounts of fulvic acid were extracted by the urea. Urea-extracted fulvic acid had the most functional groups of total acidity and phenolic OH. The most carboxyl functional groups and spectrophotometric ratios were detected in EDTA solution. At the end, by the comparison of various methods, universal method despite the low extraction amount had more functional groups and higher efficiencies compare to others.

  8. Point-of-service, quantitative analysis of ascorbic acid in aqueous humor for evaluating anterior globe integrity

    Science.gov (United States)

    Gartia, Manas R.; Misra, Santosh K.; Ye, Mao; Schwartz-Duval, Aaron; Plucinski, Lisa; Zhou, Xiangfei; Kellner, David; Labriola, Leanne T.; Pan, Dipanjan

    2015-11-01

    Limited training, high cost, and low equipment mobility leads to inaccuracies in decision making and is concerning with serious ocular injuries such as suspected ruptured globe or post-operative infections. Here, we present a novel point-of-service (POS) quantitative ascorbic acid (AA) assay with use of the OcuCheck Biosensor. The present work describes the development and clinical testing of the paper-based biosensor that measures the changes in electrical resistance of the enzyme-plated interdigitated electrodes to quantify the level of AA present in ocular fluid. We have demonstrated the proof-of-concept of the biosensor testing 16 clinical samples collected from aqueous humor of patients undergoing therapeutic anterior chamber paracentesis. Comparing with gold standard colorimetric assay for AA concentration, OcuCheck showed accuracy of >80%, sensitivity of >88% and specificity of >71%. At present, there are no FDA-approved POS tests that can directly measures AA concentration levels in ocular fluid. We envisage that the device can be realized as a handheld, battery powered instrument that will have high impact on glaucoma care and point-of-care diagnostics of penetrating ocular globe injuries.

  9. Quantitative genetic bases of anthocyanin variation in grape (Vitis vinifera L. ssp. sativa) berry: a quantitative trait locus to quantitative trait nucleotide integrated study.

    Science.gov (United States)

    Fournier-Level, Alexandre; Le Cunff, Loïc; Gomez, Camila; Doligez, Agnès; Ageorges, Agnès; Roux, Catherine; Bertrand, Yves; Souquet, Jean-Marc; Cheynier, Véronique; This, Patrice

    2009-11-01

    The combination of QTL mapping studies of synthetic lines and association mapping studies of natural diversity represents an opportunity to throw light on the genetically based variation of quantitative traits. With the positional information provided through quantitative trait locus (QTL) mapping, which often leads to wide intervals encompassing numerous genes, it is now feasible to directly target candidate genes that are likely to be responsible for the observed variation in completely sequenced genomes and to test their effects through association genetics. This approach was performed in grape, a newly sequenced genome, to decipher the genetic architecture of anthocyanin content. Grapes may be either white or colored, ranging from the lightest pink to the darkest purple tones according to the amount of anthocyanin accumulated in the berry skin, which is a crucial trait for both wine quality and human nutrition. Although the determinism of the white phenotype has been fully identified, the genetic bases of the quantitative variation of anthocyanin content in berry skin remain unclear. A single QTL responsible for up to 62% of the variation in the anthocyanin content was mapped on a Syrah x Grenache F(1) pseudo-testcross. Among the 68 unigenes identified in the grape genome within the QTL interval, a cluster of four Myb-type genes was selected on the basis of physiological evidence (VvMybA1, VvMybA2, VvMybA3, and VvMybA4). From a core collection of natural resources (141 individuals), 32 polymorphisms revealed significant association, and extended linkage disequilibrium was observed. Using a multivariate regression method, we demonstrated that five polymorphisms in VvMybA genes except VvMybA4 (one retrotransposon, three single nucleotide polymorphisms and one 2-bp insertion/deletion) accounted for 84% of the observed variation. All these polymorphisms led to either structural changes in the MYB proteins or differences in the VvMybAs promoters. We concluded that

  10. 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…

  11. A Quantitative Tool for Producing DNA-Based Diagnostic Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Tom J. Whitaker

    2008-07-11

    The purpose of this project was to develop a precise, quantitative method to analyze oligodeoxynucleotides (ODNs) on an array to enable a systematic approach to quality control issues affecting DNA microarrays. Two types of ODN's were tested; ODN's formed by photolithography and ODN's printed onto microarrays. Initial work in Phase I, performed in conjunction with Affymetrix, Inc. who has a patent on a photolithographic in situ technique for creating DNA arrays, was very promising but did seem to indicate that the atomization process was not complete. Soon after Phase II work was under way, Affymetrix had further developed fluorescent methods and indicated they were no longer interested in our resonance ionization technique. This was communicated to the program manager and it was decided that the project would continue and be focused on printed ODNs. The method being tested is called SIRIS, Sputter-Initiated Resonance Ionization Spectroscopy. SIRIS has been shown to be a highly sensitive, selective, and quantitative tool for atomic species. This project was aimed at determining if an ODN could be labeled in such a way that SIRIS could be used to measure the label and thus provide quantitative measurements of the ODN on an array. One of the largest problems in this study has been developing a method that allows us to know the amount of an ODN on a surface independent of the SIRIS measurement. Even though we could accurately determine the amount of ODN deposited on a surface, the amount that actually attached to the surface is very difficult to measure (hence the need for a quantitative tool). A double-labeling procedure was developed in which 33P and Pt were both used to label ODNs. The radioactive 33P could be measured by a proportional counter that maps the counts in one dimension. This gave a good measurement of the amount of ODN remaining on a surface after immobilization and washing. A second label, Pt, was attached to guanine nucleotides in the

  12. 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 feed

  13. Apparent and quantitative loss of fatty acids and triacylglycerols at frying temperatures

    Directory of Open Access Journals (Sweden)

    Berdeaux, O.

    2012-09-01

    Full Text Available Olive and sunflower oils were heated at 180 °C for 5, 10 and 15 hours with the aim of defining the changes in the contents of fatty acid methyl esters (FAME and triacylglycerols (TAG under frying conditions. Differences between apparent and real loss of FAME or TAG are defined for an adequate interpretation of the changes taking place at high temperature. Such differences depend on the expression of the results and frequently result in erroneous conclusions. Results showed that from the normalized composition it could be deduced that only the most unsaturated FAME (C18:2 or TAG containing it was significantly altered. However, quantitative data indicated that all the unsaturated FAME were degraded in samples of olive oil and sunflower oil whose levels of alteration ranged from 14.6 to 35.4% polar compounds. With regard to TAG, their loss depended on both the number of double bonds and the concentration of the linoleyl group, which is the most unsaturated fatty acyl group in both oils.

    Aceites de oliva y girasol se calentaron a 180 °C durante 5, 10 y 15 horas con el objetivo de definir los cambios en la concentración de ácidos grasos y especies de triglicéridos en condiciones de fritura. Se definen las diferencias entre la pérdida aparente y cuantitativa de ácidos grasos y triglicéridos que dependen de la forma de expresión de los resultados dando lugar en muchas ocasiones a interpretaciones erróneas. Así, a partir de la composición normalizada, podría deducirse que sólo el ácido graso más insaturado en los aceites (C18:2 se altera. Sin embargo, los datos cuantitativos muestran claramente que en muestras con niveles de compuestos polares entre 14.6 y 35.4%, todos los ácidos grasos insaturados sufren degradación significativa en ambos aceites. Con respecto a los cambios en los distintos triglicéridos, su pérdida cuantitativa dependió no sólo de su número de dobles enlaces sino también del contenido del ácido m

  14. Study of sample preparation for quantitative analysis of amino acids in human sweat by liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Delgado-Povedano, M M; Calderón-Santiago, M; Priego-Capote, F; Luque de Castro, M D

    2016-01-01

    The determination of physiological levels of amino acids is important to aid in the diagnosis and treatment of several diseases and nutritional status of individuals. Amino acids are frequently determined in biofluids such as blood (serum or plasma) and urine; however, there are less common biofluids with different concentration profiles of amino acids that could be of interest. One of these biofluids is sweat that can be obtained in a non-invasive manner and is characterized by low complex composition. The analysis of amino acids in human sweat requires the development of sample preparation strategies according to the sample matrix and small collected volume. The influence of sample preparation on the quantitative analysis of amino acids in sweat by LC-MS/MS has been assessed through a comparison between two strategies: dilution of sweat and centrifugal microsolid-phase extraction (c-μSPE). In both cases, several dilution factors were assayed for in-depth knowledge of the matrix effects, and the use of c-μSPE provided the best results in terms of accuracy. The behavior of the target analytes was a function of the dilution factor, thus providing a pattern for sample preparation that depended on the amino acid to be determined. The concentration of amino acids in sweat ranges between 6.20 ng mL(-1) (for homocysteine) and 259.77 µg mL(-1) (for serine) with precision, expressed as relative standard deviation, within 1.1-21.4%.

  15. Bipolar Membranes for Acid Base Flow Batteries

    Science.gov (United States)

    Anthamatten, Mitchell; Roddecha, Supacharee; Jorne, Jacob; Coughlan, Anna

    2011-03-01

    Rechargeable batteries can provide grid-scale electricity storage to match power generation with consumption and promote renewable energy sources. Flow batteries offer modular and flexible design, low cost per kWh and high efficiencies. A novel flow battery concept will be presented based on acid-base neutralization where protons (H+) and hydroxyl (OH-) ions react electrochemically to produce water. The large free energy of this highly reversible reaction can be stored chemically, and, upon discharge, can be harvested as usable electricity. The acid-base flow battery concept avoids the use of a sluggish oxygen electrode and utilizes the highly reversible hydrogen electrode, thus eliminating the need for expensive noble metal catalysts. The proposed flow battery is a hybrid of a battery and a fuel cell---hydrogen gas storing chemical energy is produced at one electrode and is immediately consumed at the other electrode. The two electrodes are exposed to low and high pH solutions, and these solutions are separated by a hybrid membrane containing a hybrid cation and anion exchange membrane (CEM/AEM). Membrane design will be discussed, along with ion-transport data for synthesized membranes.

  16. Quantitative analysis for nonlinear fluorescent spectra based on edges matching

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A novel spectra-edge-matching approach is proposed for the quantitative analysis of the nonlinear fluorescence spectra of the air impurities excited by a femtosecond laser.The fluorescence spectra are first denoised and compressed,both by wavelet transform,and several peak groups are then picked from each spectrum according to a threshold of intensity and are used to extract the spectral features through principal component analysis.It is indicated that the first two principle components actually cover up to 98% of the total information and are sufficient for the final concentration analysis.The analysis reveals a monotone relationship between the spectra intensity and the concentration of the air impurities,suggesting that the femtosecond laser induced fluorescence spectroscopy along with the proposed spectra analysis method can become a powerful tool for monitoring environmental pollutants.

  17. Quantitative metagenomic analyses based on average genome size normalization

    DEFF Research Database (Denmark)

    Frank, Jeremy Alexander; Sørensen, Søren Johannes

    2011-01-01

    Over the past quarter-century, microbiologists have used DNA sequence information to aid in the characterization of microbial communities. During the last decade, this has expanded from single genes to microbial community genomics, or metagenomics, in which the gene content of an environment can...... by estimating average genome sizes. This normalization can relieve comparative biases introduced by differences in community structure, number of sequencing reads, and sequencing read lengths between different metagenomes. We demonstrate the utility of this approach by comparing metagenomes from two different...... marine sources using both conventional small-subunit (SSU) rRNA gene analyses and our quantitative method to calculate the proportion of genomes in each sample that are capable of a particular metabolic trait. With both environments, to determine what proportion of each community they make up and how...

  18. Graphics processing unit-based quantitative second-harmonic generation imaging.

    Science.gov (United States)

    Kabir, Mohammad Mahfuzul; Jonayat, A S M; Patel, Sanjay; Toussaint, Kimani C

    2014-09-01

    We adapt a graphics processing unit (GPU) to dynamic quantitative second-harmonic generation imaging. We demonstrate the temporal advantage of the GPU-based approach by computing the number of frames analyzed per second from SHG image videos showing varying fiber orientations. In comparison to our previously reported CPU-based approach, our GPU-based image analysis results in ∼10× improvement in computational time. This work can be adapted to other quantitative, nonlinear imaging techniques and provides a significant step toward obtaining quantitative information from fast in vivo biological processes.

  19. Biodegradable polyesters based on succinic acid

    Directory of Open Access Journals (Sweden)

    Nikolić Marija S.

    2003-01-01

    Full Text Available Two series of aliphatic polyesters based on succinic acid were synthesized by copolymerization with adipic acid for the first series of saturated polyesters, and with fumaric acid for the second series. Polyesters were prepared starting from the corresponding dimethyl esters and 1,4-butanediol by melt transesterification in the presence of a highly effective catalyst tetra-n-butyl-titanate, Ti(0Bu4. The molecular structure and composition of the copolyesters was determined by 1H NMR spectroscopy. The effect of copolymer composition on the physical and thermal properties of these random polyesters were investigated using differential scanning calorimetry. The degree of crystallinity was determined by DSC and wide angle X-ray. The degrees of crystallinity of the saturated and unsaturated copolyesters were generally reduced with respect to poly(butylene succinate, PBS. The melting temperatures of the saturated polyesters were lower, while the melting temperatures of the unsaturated copolyesters were higher than the melting temperature of PBS. The biodegradability of the polyesters was investigated by enzymatic degradation tests. The enzymatic degradation tests were performed in a buffer solution with Candida cylindracea lipase and for the unsaturated polyesters with Rhizopus arrhizus lipase. The extent of biodegradation was quantified as the weight loss of polyester films. Also the surface of the polyester films after degradation was observed using optical microscopy. It could be concluded that the biodegradability depended strongly on the degree of crystallinity, but also on the flexibility of the chain backbone. The highest biodegradation was observed for copolyesters containing 50 mol.% of adipic acid units, and in the series of unsaturated polyesters for copolyesters containing 5 and 10 mol.% of fumarate units. Although the degree of crystallinity of the unsaturated polyesters decreased slightly with increasing unsaturation, the biodegradation

  20. DESCIFRANDO LAS BASES MOLECULARES DE LA RESISTENCIA CUANTITATIVA Deciphering the Molecular Bases of Quantitative Resistance

    Directory of Open Access Journals (Sweden)

    CAMILO LÓPEZ

    2011-08-01

    Full Text Available Uno de los factores que más afectan los cultivos son las enfermedades ocasionadas por patógenos. La resistencia vegetal ha sido clásicamente dividida en dos tipos: i completa, vertical o cualitativa que es gobernada por un solo gen e ii incompleta, horizontal o cuantitativa la cual es gobernada por varios genes. Aunque la resistencia cuantitativa provee resistencia de amplio espectro y es durable, los mecanismos moleculares subyacentes no han sido estudiados en detalle. En esta revisión se propone un modelo basado en co-localización de genes similares a los genes clásicos de resistencia cualitativa con QTLs (Quantitative Trait Loci para explicar el mecanismo involucrado en el reconocimiento del patógeno durante la resistencia cuantitativa. Además se presenta información acerca del progreso obtenido en los últimos tres años para entender este tipo de resistencia, lo que culminó con la clonación de varios genes asociados a resistencia cuantitativa. En conjunto, estos datos proveen nuevas luces sobre la naturaleza genética de este tipo de resistencia y de cómo puede ser empleada en programas de mejoramiento genético.Plant pathogens are some of the most important factors affecting crop production. Classically two general types of plant resistance to pathogens have been recognized: i complete, vertical or qualitative resistance governed by a single gene; and ii incomplete, horizontal or quantitative resistance, which is governed by several genes. Although quantitative resistance provides broad spectrum and more durable resistance, the underlying molecular mechanism involved in pathogen recognition has not been deeply studied. In this review, we proposed a model to explain the molecular mechanism involved in the pathogen recognition during the quantitative resistance. This is based on the co-localization of similar classical qualitative resistance genes with QTL (Quantitative Trait Loci. In addition, information is presented about the

  1. Quantitative twoplex glycan analysis using (12)C6 and (13)C6 stable isotope 2-aminobenzoic acid labelling and capillary electrophoresis mass spectrometry.

    Science.gov (United States)

    Váradi, Csaba; Mittermayr, Stefan; Millán-Martín, Silvia; Bones, Jonathan

    2016-12-01

    Capillary electrophoresis (CE) offers excellent efficiency and orthogonality to liquid chromatographic (LC) separations for oligosaccharide structural analysis. Combination of CE with high resolution mass spectrometry (MS) for glycan analysis remains a challenging task due to the MS incompatibility of background electrolyte buffers and additives commonly used in offline CE separations. Here, a novel method is presented for the analysis of 2-aminobenzoic acid (2-AA) labelled glycans by capillary electrophoresis coupled to mass spectrometry (CE-MS). To ensure maximum resolution and excellent precision without the requirement for excessive analysis times, CE separation conditions including the concentration and pH of the background electrolyte, the effect of applied pressure on the capillary inlet and the capillary length were evaluated. Using readily available (12/13)C6 stable isotopologues of 2-AA, the developed method can be applied for quantitative glycan profiling in a twoplex manner based on the generation of extracted ion electropherograms (EIE) for (12)C6 'light' and (13)C6 'heavy' 2-AA labelled glycan isotope clusters. The twoplex quantitative CE-MS glycan analysis platform is ideally suited for comparability assessment of biopharmaceuticals, such as monoclonal antibodies, for differential glycomic analysis of clinical material for potential biomarker discovery or for quantitative microheterogeneity analysis of different glycosylation sites within a glycoprotein. Additionally, due to the low injection volume requirements of CE, subsequent LC-MS analysis of the same sample can be performed facilitating the use of orthogonal separation techniques for structural elucidation or verification of quantitative performance.

  2. In vivo quantitative visualization of hypochlorous acid in the liver using a novel selective two-photon fluorescent probe

    Science.gov (United States)

    Wang, Haolu; Jayachandran, Aparna; Gravot, Germain; Liang, Xiaowen; Thorling, Camilla A.; Zhang, Run; Liu, Xin; Roberts, Michael S.

    2016-11-01

    Hypochlorous acid (HOCl) plays a vital role in physiological events and diseases. During hepatic ischemia-reperfusion (I/R) injury, HOCl is generated by neutrophils and diffuses into hepatocytes, causing oxidant stress-mediated injury. Although many probes have been developed to detect HOCl, most were difficult to be distinguished from endogenous fluorophores in intravital imaging and only can be employed under one-photon microscopy. A novel iridium(III) complex-based ferrocene dual-signaling chemosensor (Ir-Fc) was designed and synthesized. Ir-Fc exhibited a strong positive fluorescent response only in the presence of HOCl, whereas negligible fluorescent signals were observed upon the additions of other reactive oxygen/nitrogen species and metal ions. There was a good linear relationship between probe responsive fluorescent intensity and HOCl concentration. Ir-Fc was then intravenously injected into BALB/c mice at the final concentration of 50 μM and the mouse livers were imaged using multiphoton microscopy (MPM). In the I/R liver, reduced autofluorescence was detected by MPM, indicating the hepatocyte necrosis. Remarkable enhancement of red fluorescence was observed in hepatocytes with decreased autofluorescence, indicating the reaction of Ir-Fc with endogenous HOCl molecules. The cellular concentration of HOCl was first calculated based on the intensity of MPM images. No obvious toxic effects were observed in histological examination of major organs after Ir-Fc injection. In summary, Ir-Fc has low cytotoxicity, high specificity to HOCl, and rapid "off-on" fluorescence. It is suitable for dynamic quantitatively monitoring HOCl generation using MPM at the cellular level. This technique can be readily extended to examination of liver diseases and injury.

  3. 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…

  4. 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…

  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. 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…

  7. 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…

  8. Metabolites of IPPA, BMIPP, and DMIPP fatty acids in rats hearts: A quantitative HPLC-study

    Energy Technology Data Exchange (ETDEWEB)

    Kropp, J.; Assmann, T.; Biersack, H.J.; Wissen, H.P. (Bonn Univ. (Germany, F.R.)); Knapp, F.F. Jr. Ambrose, K.R. (Oak Ridge National Lab., TN (USA))

    1990-01-01

    The significance of the use of radioiodinated fatty acid analogues such as 15-(p-iodophenyl) pentadecanoic acid (IPPA), 15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP), and 15-(p-iodophenyl)-3-dimethylpentadecanoic acid (DMIPP) for the evaluation of regional myocardial fatty acid uptake is well documented. An understanding of the relative incorporation of these fatty acid analogues into various fatty acid pools is important to correlate fatty acid uptake and release with flux through the various metabolic pathways. While the free fatty acid (FFA) pool is immediately available for oxidation to meet energy demands for contraction under normoxic conditions, the FFA are also stored as triglycerides (TG) for oxidation at a later period. Although the incorporation of IPPA, BMIPP, and DMIPP into the major phospholipid classes has not been previously investigated, demonstration of the incorporation of IPPA and BMIPP into phospholipids would be important as further evidence that these modified'' fatty acids are, at least qualitatively, metabolized through the usual metabolic pathways. The goals of the present studies were thus to develop the necessary HPLC techniques and evaluate the incorporation of IPPA, BMIPP, and DMIPP into complex endogenous lipids in dual label studies. 2 refs., 6 figs.

  9. Integrated isolation and quantitative analysis of exosome shuttled proteins and nucleic acids using immunocapture approaches.

    Science.gov (United States)

    Zarovni, Natasa; Corrado, Antonietta; Guazzi, Paolo; Zocco, Davide; Lari, Elisa; Radano, Giorgia; Muhhina, Jekatarina; Fondelli, Costanza; Gavrilova, Julia; Chiesi, Antonio

    2015-10-01

    Clinical implementation of exosome based diagnostic and therapeutic applications is still limited by the lack of standardized technologies that integrate efficient isolation of exosomes with comprehensive detection of relevant biomarkers. Conventional methods for exosome isolation based on their physical properties such as size and density (filtration, ultracentrifugation or density gradient), or relying on their differential solubility (chemical precipitation) are established primarily for processing of cell supernatants and later adjusted to complex biological samples such as plasma. Though still representing gold standard in the field, these methods are clearly suboptimal for processing of routine clinical samples and have intrinsic limits that impair their use in biomarker discovery and development of novel diagnostics. Immunoisolation (IA) offers unique advantages for the recovery of exosomes from complex and viscous fluids, in terms of increased efficiency and specificity of exosome capture, integrity and selective origin of isolated vesicles. We have evaluated several commercially available solutions for immunoplate- and immunobead-based affinity isolation and have further optimized protocols to decrease non-specific binding due to exosomes complexity and matrix contaminants. In order to identify best molecular targets for total exosome capture from diverse biological sources, as well as for selective enrichment in populations of interest (e.g. tumor derived exosomes) several exosome displayed proteins and respective antibodies have been evaluated for plate and bead functionalisation. Moreover, we have optimized and directly implemented downstream steps allowing on-line quantification and characterization of bound exosome markers, namely proteins and RNAs. Thus assembled assays enabled rapid overall quantification and validation of specific exosome associated targets in/on plasma exosomes, with multifold increased yield and enrichment ratio over benchmarking

  10. DISQOVER the Landcover - R based tools for quantitative vegetation reconstruction

    Science.gov (United States)

    Theuerkauf, Martin; Couwenberg, John; Kuparinen, Anna; Liebscher, Volkmar

    2016-04-01

    Quantitative methods have gained increasing attention in the field of vegetation reconstruction over the past decade. The DISQOVER package implements key tools in the R programming environment for statistical computing. This implementation has three main goals: 1) Provide a user-friendly, transparent, and open implementation of the methods 2) Provide full flexibility in all parameters (including the underlying pollen dispersal model) 3) Provide a sandbox for testing the sensitivity of the methods. We illustrate the possibilities of the package with tests of the REVEALS model and of the extended downscaling approach (EDA). REVEALS (Sugita 2007) is designed to translate pollen data from large lakes into regional vegetation composition. We applied REVEALSinR on pollen data from Lake Tiefer See (NE-Germany) and validated the results with historic landcover data. The results clearly show that REVEALS is sensitive to the underlying pollen dispersal model; REVEALS performs best when applied with the state of the art Lagrangian stochastic dispersal model. REVEALS applications with the conventional Gauss model can produce realistic results, but only if unrealistic pollen productivity estimates are used. The EDA (Theuerkauf et al. 2014) employs pollen data from many sites across a landscape to explore whether species distributions in the past were related to know stable patterns in the landscape, e.g. the distribution of soil types. The approach had so far only been implemented in simple settings with few taxa. Tests with EDAinR show that it produces sharp results in complex settings with many taxa as well. The DISQOVER package is open source software, available from disqover.uni-greifswald.de. This website can be used as a platform to discuss and improve quantitative methods in vegetation reconstruction. To introduce the tool we plan a short course in autumn of this year. This study is a contribution to the Virtual Institute of Integrated Climate and Landscape Evolution

  11. Understanding Acid-Base Concepts: Evaluating the Efficacy of a Senior High School Student-Centred Instructional Program in Indonesia

    Science.gov (United States)

    Rahayu, Sri; Chandrasegaran, A. L.; Treagust, David F.; Kita, Masakazu; Ibnu, Suhadi

    2011-01-01

    This study was a mixed quantitative-qualitative research to evaluate the efficacy of a designed student-centred instructional (DSCI) program for teaching about acids and bases. The teaching innovation was designed based on constructivist, hands-on inquiry and context-based approaches and implemented in seven 45-min lessons with a class of 36 grade…

  12. Understanding Acid-Base Concepts: Evaluating the Efficacy of a Senior High School Student-Centred Instructional Program in Indonesia

    Science.gov (United States)

    Rahayu, Sri; Chandrasegaran, A. L.; Treagust, David F.; Kita, Masakazu; Ibnu, Suhadi

    2011-01-01

    This study was a mixed quantitative-qualitative research to evaluate the efficacy of a designed student-centred instructional (DSCI) program for teaching about acids and bases. The teaching innovation was designed based on constructivist, hands-on inquiry and context-based approaches and implemented in seven 45-min lessons with a class of 36 grade…

  13. SILAC-Based Quantitative Strategies for Accurate Histone Posttranslational Modification Profiling Across Multiple Biological Samples.

    Science.gov (United States)

    Cuomo, Alessandro; Soldi, Monica; Bonaldi, Tiziana

    2017-01-01

    Histone posttranslational modifications (hPTMs) play a key role in regulating chromatin dynamics and fine-tuning DNA-based processes. Mass spectrometry (MS) has emerged as a versatile technology for the analysis of histones, contributing to the dissection of hPTMs, with special strength in the identification of novel marks and in the assessment of modification cross talks. Stable isotope labeling by amino acid in cell culture (SILAC), when adapted to histones, permits the accurate quantification of PTM changes among distinct functional states; however, its application has been mainly confined to actively dividing cell lines. A spike-in strategy based on SILAC can be used to overcome this limitation and profile hPTMs across multiple samples. We describe here the adaptation of SILAC to the analysis of histones, in both standard and spike-in setups. We also illustrate its coupling to an implemented "shotgun" workflow, by which heavy arginine-labeled histone peptides, produced upon Arg-C digestion, are qualitatively and quantitatively analyzed in an LC-MS/MS system that combines ultrahigh-pressure liquid chromatography (UHPLC) with new-generation Orbitrap high-resolution instrument.

  14. Quantitative sequencing of 5-formylcytosine in DNA at single-base resolution

    Science.gov (United States)

    Booth, Michael J.; Marsico, Giovanni; Bachman, Martin; Beraldi, Dario; Balasubramanian, Shankar

    2014-05-01

    Recently, the cytosine modifications 5-hydroxymethylcytosine (5hmC) and 5-formylcytosine (5fC) were found to exist in the genomic deoxyribonucleic acid (DNA) of a wide range of mammalian cell types. It is now important to understand their role in normal biological function and disease. Here we introduce reduced bisulfite sequencing (redBS-Seq), a quantitative method to decode 5fC in DNA at single-base resolution, based on a selective chemical reduction of 5fC to 5hmC followed by bisulfite treatment. After extensive validation on synthetic and genomic DNA, we combined redBS-Seq and oxidative bisulfite sequencing (oxBS-Seq) to generate the first combined genomic map of 5-methylcytosine, 5hmC and 5fC in mouse embryonic stem cells. Our experiments revealed that in certain genomic locations 5fC is present at comparable levels to 5hmC and 5mC. The combination of these chemical methods can quantify and precisely map these three cytosine derivatives in the genome and will help provide insights into their function.

  15. Liquid Crystalline Furandicarboxylic Acid-based Aaromatic Polyesters

    NARCIS (Netherlands)

    WILSENS, CAROLUS HENRICUS R. MARIA; RASTOGI, SANJAY; VELD, MARTIJN ARNOLDUS JOHANNES; KLOP, ENNO ANTON; NOORDOVER, BART ADRIANUS JOHANNES

    2013-01-01

    The invention pertains to a fully aromatic liquid crystalline furandicarboxylic acid- based aromatic polyester obtainable from a mixture of monomers comprising 2,5- furandicarboxylic acid, p-hydroxybenzoic acid, an aromatic diol, and 5-40 mol% of an aromatic monocarboxylic acid selected from vanilli

  16. Quality consistency evaluation of Melissa officinalis L. commercial herbs by HPLC fingerprint and quantitation of selected phenolic acids.

    Science.gov (United States)

    Arceusz, Agnieszka; Wesolowski, Marek

    2013-09-01

    To evaluate the quality consistency of commercial medicinal herbs, a simple and reliable HPLC method with UV-vis detector was developed, both for fingerprint analysis and quantitation of some pharmacologically active constituents (marker compounds). Melissa officinalis L. (lemon balm) was chosen for this study because it is widely used as an aromatic, culinary and medicine remedy. About fifty peaks were found in each chromatogram of a lemon balm extract, including twelve satisfactorily resolved characteristic peaks. A reference chromatographic fingerprint for the studied medicinal herb was calculated using Matlab 9.1 software as a result of analysing all the 19 lemon balm samples obtained from 12 Polish manufacturers. The similarity values and the results of principal component analysis revealed that all the samples were highly correlated with the reference fingerprint and could be accurately classified in relation to their quality consistency. Next, a quantitation of selected phenolic acids in the studied samples was performed. The results have shown that the levels of phenolic acids, i.e. gallic, chlorogenic, syringic, caffeic, ferulic and rosmarinic were as follows (mg/g of dry weight): 0.001-0.067, 0.010-0.333, 0.007-0.553, 0.047-0.705, 0.006-1.589 and 0.158-48.608, respectively. Statistical analysis indicated that rosmarinic acid occurs in M. officinalis at the highest level, whereas gallic acid in the lowest. A detailed inspection of these data has also revealed that reference chromatographic fingerprints combined with quantitation of pharmacologically active constituents of the plant could be used as an efficient strategy for monitoring of the lemon balm quality consistency. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Quantitative Study on Polymer Flocculation Mechanism Based on Mathematical Morphology

    Institute of Scientific and Technical Information of China (English)

    GUO Ling-xiang; WANG Chen-yi

    2006-01-01

    Until now, understanding of polymer flocculation has remained restricted within the qualitative explanations of the bridge unite theory and the electricity neutralization theory, because people not only lacked the systemic knowledge of the polymer flocculation mechanism, the flocculation dynamic process study and the flocculation effect estimate, but also could not penetrate within the flocculation process microscopic field to obtain the structural character parameters such as floccule structure, the frame bridge models and so on. In this paper, not only coal slurry flocculation images were photographed by using the transmission electron microscope, but also the basic theory of the mathematical morphology was applied to the coal slurry flocculation image processing. The steps and methods of the mathematical morphology were expounded in detail. The micro-structural parameters such as the flocculate size and the bridge length were obtained, which combined the microscopic flocculation grain configuration observations with the macroscopic flocculation effect, so as to get the maximum amount of veracious information to describe and explain the whole flocculation course by rule and line. On this basis, not only the flocculation models of polymers in the coal slurry are suggested, but the quantitative study on flocculation mechanism has been achieved.

  18. QUANTITATIVE DETERMINATION OF FATTY ACIDS IN INFANT FORMULA BY GAS CHROMATOGRAPHY WITHOUT DERIVATIZATION

    Directory of Open Access Journals (Sweden)

    M. R. Oveisi

    2006-08-01

    Full Text Available Fatty acids play important roles in biological systems and the newborns fatty acids requirements are covered only by the milk. It is of particular interest to qualify the content of the fatty acids in the milk. This study was performed to determine the levels of some fatty acids in the infant formulas and also to describe a method without derivatization for the fatty acids analysis and applying it to the control of infant formulas. Free fatty acids were produced by adding isopropanol- KOH to milk fat extract and heating it to saponify and acidify by H2SO4. Free fatty acids were extracted and were quantified by capillary gas chromatography on a fused silica column (AT-1000 and flame ionization detector. The average experimental values of lauric, palmitic, stearic and linoleic fatty acids contents of twenty infant formulas were 6.47, 16.52, 2.11 and 14.56 g/100g, respectively. The obtained experimental values of lauric and linoleic fatty acids contents of twenty infant formulas were in good agreement with the values proposed by standards of codex alimentary.

  19. Bovine serum albumin detection and quantitation based on capacitance measurements of liquid crystals

    Science.gov (United States)

    Lin, Chi-Hao; Lee, Mon-Juan; Lee, Wei

    2016-08-01

    Liquid crystal (LC)-based biosensing is generally limited by the lack of accurate quantitative strategies. This study exploits the unique electric capacitance properties of LCs to establish quantitative assay methods for bovine serum albumin (BSA) biomolecules. By measuring the voltage-dependent electric capacitance of LCs under an alternating-current field with increasing amplitude, positive correlations were derived between the BSA concentration and the electric capacitance parameters of LCs. This study demonstrates that quantitative analysis can be achieved in LC-based biosensing through electric capacitance measurements extensively employed in LCD research and development.

  20. A droplet-based, optofluidic device for high-throughput, quantitative bioanalysis

    OpenAIRE

    Guo, Feng; Lapsley, Michael Ian; Nawaz, Ahmad Ahsan; Zhao, Yanhui; Lin, Sz-Chin Steven; Chen, Yuchao; Yang, Shikuan; Zhao, Xing-Zhong; Huang, Tony Jun

    2012-01-01

    Analysis of chemical or biomolecular contents in a tiny amount of specimen presents a significant challenge in many biochemical studies and diagnostic applications. In this work, we present a single-layer, optofluidic device for real-time, high-throughput, quantitative analysis of droplet contents. Our device integrates an optical fiber-based, on-chip detection unit with a droplet-based microfluidic unit. It can quantitatively analyze the contents of individual droplets in real-time. It also ...

  1. Quantitative analysis of mutation and selection pressures on base composition skews in bacterial chromosomes

    Directory of Open Access Journals (Sweden)

    Chen Carton W

    2007-08-01

    Full Text Available Abstract Background Most bacterial chromosomes exhibit asymmetry of base composition with respect to leading vs. lagging strands (GC and AT skews. These skews reflect mainly those in protein coding sequences, which are driven by asymmetric mutation pressures during replication and transcription (notably asymmetric cytosine deamination plus subsequent selection for preferred structures, signals, amino acid or codons. The transcription-associated effects but not the replication-associated effects contribute to the overall skews through the uneven distribution of the coding sequences on the leading and lagging strands. Results Analysis of 185 representative bacterial chromosomes showed diverse and characteristic patterns of skews among different clades. The base composition skews in the coding sequences were used to derive quantitatively the effect of replication-driven mutation plus subsequent selection ('replication-associated pressure', RAP, and the effect of transcription-driven mutation plus subsequent selection at translation level ('transcription-associate pressure', TAP. While different clades exhibit distinct patterns of RAP and TAP, RAP is absent or nearly absent in some bacteria, but TAP is present in all. The selection pressure at the translation level is evident in all bacteria based on the analysis of the skews at the three codon positions. Contribution of asymmetric cytosine deamination was found to be weak to TAP in most phyla, and strong to RAP in all the Proteobacteria but weak in most of the Firmicutes. This possibly reflects the differences in their chromosomal replication machineries. A strong negative correlation between TAP and G+C content and between TAP and chromosomal size were also revealed. Conclusion The study reveals the diverse mutation and selection forces associated with replication and transcription in various groups of bacteria that shape the distinct patterns of base composition skews in the chromosomes during

  2. Development of a colorimetric assay for rapid quantitative measurement of clavulanic acid in microbial samples.

    Science.gov (United States)

    Dai, Xida; Xiang, Sihai; Li, Jia; Gao, Qiang; Yang, Keqian

    2012-02-01

    We developed a colorimetric assay to quantify clavulanic acid (CA) in culture broth of Streptomyces clavuligerus, to facilitate screening of a large number of S. clavuligerus mutants. The assay is based on a β-lactamase-catalyzed reaction, in which the yellow substrate nitrocefin (λ (max)=390 nm) is converted to a red product (λ (max)=486 nm). Since CA can irreversibly inhibit β-lactamase activity, the level of CA in a sample can be measured as a function of the A (390)/A (486) ratio in the assay mixture. The sensitivity and detection window of the assay were determined to be 50 μg L(-1) and 50 μg L(-1) to 10 mg L(-1), respectively. The reliability of the assay was confirmed by comparing assay results with those obtained by HPLC. The assay was used to screen a pool of 65 S. clavuligerus mutants and was reliable for identifying CA over-producing mutants. Therefore, the assay saves time and labor in large-scale mutant screening and evaluation tasks. The detection window and the reliability of this assay are markedly better than those of previously reported CA assays. This assay method is suitable for high throughput screening of microbial samples and allows direct visual observation of CA levels on agar plates.

  3. Quantitative Analysis of Variability and Uncertainty in Environmental Data and Models. Volume 1. Theory and Methodology Based Upon Bootstrap Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Frey, H. Christopher [North Carolina State University, Raleigh, NC (United States); Rhodes, David S. [North Carolina State University, Raleigh, NC (United States)

    1999-04-30

    This is Volume 1 of a two-volume set of reports describing work conducted at North Carolina State University sponsored by Grant Number DE-FG05-95ER30250 by the U.S. Department of Energy. The title of the project is “Quantitative Analysis of Variability and Uncertainty in Acid Rain Assessments.” The work conducted under sponsorship of this grant pertains primarily to two main topics: (1) development of new methods for quantitative analysis of variability and uncertainty applicable to any type of model; and (2) analysis of variability and uncertainty in the performance, emissions, and cost of electric power plant combustion-based NOx control technologies. These two main topics are reported separately in Volumes 1 and 2.

  4. A Quantitative Analysis of Published Skull Base Endoscopy Literature.

    Science.gov (United States)

    Hardesty, Douglas A; Ponce, Francisco A; Little, Andrew S; Nakaji, Peter

    2016-02-01

    Objectives Skull base endoscopy allows for minimal access approaches to the sinonasal contents and cranial base. Advances in endoscopic technique and applications have been published rapidly in recent decades. Setting We utilized an Internet-based scholarly database (Web of Science, Thomson Reuters) to query broad-based phrases regarding skull base endoscopy literature. Participants All skull base endoscopy publications. Main Outcome Measures Standard bibliometrics outcomes. Results We identified 4,082 relevant skull base endoscopy English-language articles published between 1973 and 2014. The 50 top-cited publications (n = 51, due to articles with equal citation counts) ranged in citation count from 397 to 88. Most of the articles were clinical case series or technique descriptions. Most (96% [49/51])were published in journals specific to either neurosurgery or otolaryngology. Conclusions A relatively small number of institutions and individuals have published a large amount of the literature. Most of the publications consisted of case series and technical advances, with a lack of randomized trials.

  5. Quantitative assessment of hip osteoarthritis based on image texture analysis.

    Science.gov (United States)

    Boniatis, I S; Costaridou, L I; Cavouras, D A; Panagiotopoulos, E C; Panayiotakis, G S

    2006-03-01

    A non-invasive method was developed to investigate the potential capacity of digital image texture analysis in evaluating the severity of hip osteoarthritis (OA) and in monitoring its progression. 19 textural features evaluating patterns of pixel intensity fluctuations were extracted from 64 images of radiographic hip joint spaces (HJS), corresponding to 32 patients with verified unilateral or bilateral OA. Images were enhanced employing custom developed software for the delineation of the articular margins on digitized pelvic radiographs. The severity of OA for each patient was assessed by expert orthopaedists employing the Kellgren and Lawrence (KL) scale. Additionally, an index expressing HJS-narrowing was computed considering patients from the unilateral OA-group. A textural feature that quantified pixel distribution non-uniformity (grey level non-uniformity, GLNU) demonstrated the strongest correlation with the HJS-narrowing index among all extracted features and utilized in further analysis. Classification rules employing GLNU feature were introduced to characterize a hip as normal or osteoarthritic and to assign it to one of three severity categories, formed in accordance with the KL scale. Application of the proposed rules resulted in relatively high classification accuracies in characterizing a hip as normal or osteoarthritic (90.6%) and in assigning it to the correct KL scale category (88.9%). Furthermore, the strong correlation between the HJS-narrowing index and the pathological GLNU (r = -0.9, p<0.001) was utilized to provide percentages quantifying hip OA-severity. Texture analysis may contribute in the quantitative assessment of OA-severity, in the monitoring of OA-progression and in the evaluation of a chondroprotective therapy.

  6. Quantitative analysis of the modes of growth inhibition by weak organic acids in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Ullah, A.; Orij, R.; Brul, S.; Smits, G.J.

    2012-01-01

    Weak organic acids are naturally occurring compounds that are commercially used as preservatives in the food and beverage industries. They extend the shelf life of food products by inhibiting microbial growth. There are a number of theories that explain the antifungal properties of these weak acids,

  7. Nicotiflorin, rutin and chlorogenic acid: phenylpropanoids involved differently in quantitative resistance of potato tubers to biotrophic and necrotrophic pathogens.

    Science.gov (United States)

    Kröner, Alexander; Marnet, Nathalie; Andrivon, Didier; Val, Florence

    2012-08-01

    Physiological and molecular mechanisms underlying quantitative resistance of plants to pathogens are still poorly understood, but could depend upon differences in the intensity or timing of general defense responses. This may be the case for the biosynthesis of phenolics which are known to increase after elicitation by pathogens. We thus tested the hypothesis that differences in quantitative resistance were related to differential induction of phenolics by pathogen-derived elicitors. Five potato cultivars (Solanum tuberosum, L.) spanning a range of quantitative resistance were treated with a concentrated culture filtrate (CCF) of Phytophthora infestans or purified lipopolysaccharides (LPS) from Pectobacterium atrosepticum. The kinetic of phenolics accumulation was followed and a set of typical phenolics was identified: chlorogenic acid, phenolamides and flavonols including rutin (quercetin-3-O-rutinoside) and nicotiflorin (kaempferol-3-O-rutinoside). Our results showed that CCF but not LPS induced differential accumulation of major phenolics among cultivars. Total phenolics were related with resistance to P. atrosepticum but not to P. infestans. However, nicotiflorin was inversely related with resistance to both pathogens. Rutin, but not nicotiflorin, inhibited pathogen growth in vitro at physiological concentrations. These data therefore suggest that (i) several phenolics are candidate markers for quantitative resistance in potato, (ii) some of these are pathogen specific although they are produced by a general defense pathway, (iii) resistance marker molecules do not necessarily have antimicrobial activity, and (iv) the final content of these target molecules-either constitutive or induced-is a better predictor of resistance than their inducibility by pathogen elicitors.

  8. Quantitative determination of citric acid in seminal plasma by using Raman spectroscopy.

    Science.gov (United States)

    Huang, Zufang; Chen, Xiwen; Li, Yongzeng; Chen, Jinhua; Lin, Juqiang; Wang, Jing; Lei, Jinping; Chen, Rong

    2013-07-01

    In this study, Raman spectroscopy was first used to study the linear relationship between Raman spectral intensities and citric acid concentrations in aqueous solution. By using the specific Raman band of 942 cm(-1), concentrations of citric acid ranging from 2 to 20 mg/mL were observed linearly (R(2) = 0.993), and the limit of detection was 1.0 mg/mL. Then, citric acid detection in clinical seminal plasma ultrafiltrate samples was performed, and the intensity of the Raman-specific peak demonstrates a good linear correlation (R(2) = 0.946) with citric acid concentrations determined by the enzymatic method. Our results showed that Raman spectroscopy has the potential of being applied to detect concentrations of citric acid in seminal plasma in clinic.

  9. Quantitative multiplex detection of biomarkers on a waveguide-based biosensor using quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Hongzhi [Los Alamos National Laboratory; Mukundan, Harshini [Los Alamos National Laboratory; Martinez, Jennifer S [Los Alamos National Laboratory; Swanson, Basil I [Los Alamos National Laboratory; Anderson, Aaron S [Los Alamos National Laboratory; Grace, Kevin [Los Alamos National Laboratory

    2009-01-01

    color imaging of live cells using QD-bioconjugates [Jaiswal 2003]. Gao [Gao 2004] and So [So 2006] have used QDs as probes for in-vivo cancer targeting and imaging. Medintz et al. reported self-assembled QD-based biosensors for detection of analytes based on energy transfer [Medintz 2003]. Others have developed an approach for multiplex optical encoding of biomolecules using QDs [Han 2001]. Immunoassays have also benefited from the advantages of QDs. Recently, dihydrolipoic acid (DHLA) capped-QDs have been attached to antibodies and used as fluorescence reporters in plate-based multiplex immunoassays [Goodman 2004]. However, DHLA-QDs are associated with low quantum efficiency and are unstable at neutral pH. These problems limit the application of this technology to the sensitive detection of biomolecules, especially in complex biological samples. Thus, the development of a rapid, sensitive, quantitative, and specific multiplex platform for the detection of biomarkers in difficult samples remains an elusive target. The goal stated above has applications in many fields including medical diagnostics, biological research, and threat reduction. The current decade alone has seen the development of a need to rapidly and accurately detect potential biological warfare agents. For example, current methods for the detection of anthrax are grossly inadequate for a variety of reasons including long incubation time (5 days from time of exposure to onset of symptoms) and non-specific ('flu-like') symptoms. When five employees of the United State Senate were exposed to B. anthracis in the mail (2001), only one patient had a confirmed diagnosis before death. Since then, sandwich immunoassays using both colorimetric and fluorescence detectors have been developed for key components of the anthrax lethal toxin, namely protective antigen (PA), lethal factor (LF), and the edema factor [Mourez 2001]. While these platforms were successful in assays against anthrax toxins, the

  10. The IBO germination quantitative trait locus encodes a phosphatase 2C-related variant with a nonsynonymous amino acid change that interferes with abscisic acid signaling.

    Science.gov (United States)

    Amiguet-Vercher, Amélia; Santuari, Luca; Gonzalez-Guzman, Miguel; Depuydt, Stephen; Rodriguez, Pedro L; Hardtke, Christian S

    2015-02-01

    Natural genetic variation is crucial for adaptability of plants to different environments. Seed dormancy prevents precocious germination in unsuitable conditions and is an adaptation to a major macro-environmental parameter, the seasonal variation in temperature and day length. Here we report the isolation of IBO, a quantitative trait locus (QTL) that governs c. 30% of germination rate variance in an Arabidopsis recombinant inbred line (RIL) population derived from the parental accessions Eilenburg-0 (Eil-0) and Loch Ness-0 (Lc-0). IBO encodes an uncharacterized phosphatase 2C-related protein, but neither the Eil-0 nor the Lc-0 variant, which differ in a single amino acid, have any appreciable phosphatase activity in in vitro assays. However, we found that the amino acid change in the Lc-0 variant of the IBO protein confers reduced germination rate. Moreover, unlike the Eil-0 variant of the protein, the Lc-0 variant can interfere with the activity of the phosphatase 2C ABSCISIC ACID INSENSITIVE 1 in vitro. This suggests that the Lc-0 variant possibly interferes with abscisic acid signaling, a notion that is supported by physiological assays. Thus, we isolated an example of a QTL allele with a nonsynonymous amino acid change that might mediate local adaptation of seed germination timing.

  11. A multiplex GC-MS/MS technique for the sensitive and quantitative single-run analysis of acidic phytohormones and related compounds, and its application to Arabidopsis thaliana.

    Science.gov (United States)

    Müller, Axel; Düchting, Petra; Weiler, Elmar W

    2002-11-01

    A highly sensitive and accurate multiplex gas chromatography-tandem mass spectrometry (GC-MS/MS) technique is reported for indole-3-acetic acid, abscisic acid, jasmonic acid, 12-oxo-phytodienoic acid and salicylic acid. The optimized setup allows the routine processing and analysis of up to 60 plant samples of between 20 and 200 mg of fresh weight per day. The protocol was designed and the equipment used was chosen to facilitate implementation of the method into other laboratories and to provide access to state-of-the-art analytical tools for the acidic phytohormones and related signalling molecules. Whole-plant organ-distribution maps for indole-3-acetic acid, abscisic acid, jasmonic acid, 12-oxo-phytodienoic acid and salicylic acid were generated for Arabidopsis thaliana (L.) Heynh. For leaves of A. thaliana, a spatial resolution of hormone quantitation down to approximately 2 mm(2) was achieved.

  12. Quantitative analysis of mixed hydrofluoric and nitric acids using Raman spectroscopy with partial least squares regression.

    Science.gov (United States)

    Kang, Gumin; Lee, Kwangchil; Park, Haesung; Lee, Jinho; Jung, Youngjean; Kim, Kyoungsik; Son, Boongho; Park, Hyoungkuk

    2010-06-15

    Mixed hydrofluoric and nitric acids are widely used as a good etchant for the pickling process of stainless steels. The cost reduction and the procedure optimization in the manufacturing process can be facilitated by optically detecting the concentration of the mixed acids. In this work, we developed a novel method which allows us to obtain the concentrations of hydrofluoric acid (HF) and nitric acid (HNO(3)) mixture samples with high accuracy. The experiments were carried out for the mixed acids which consist of the HF (0.5-3wt%) and the HNO(3) (2-12wt%) at room temperature. Fourier Transform Raman spectroscopy has been utilized to measure the concentration of the mixed acids HF and HNO(3), because the mixture sample has several strong Raman bands caused by the vibrational mode of each acid in this spectrum. The calibration of spectral data has been performed using the partial least squares regression method which is ideal for local range data treatment. Several figures of merit (FOM) were calculated using the concept of net analyte signal (NAS) to evaluate performance of our methodology.

  13. Bedside Analysis of Acid-Base Balance

    Directory of Open Access Journals (Sweden)

    Yu. S. Podlesskikh

    2006-01-01

    Full Text Available Laboratory service is one of the most hang-the-expense items in the cost of treatment of patients in an intensive care unit. Isolated acid-base balance (ABB impairments are rare in clinical practice. These impairments are generally combined and they frequently cause a drastic change in the pH value of blood. Early detection of their origin and its elimination are of profound importance in these situations. Miniaturization of analyzers has made it possible to conduct some investigations and particularly to determine ABB just in the intensive care unit or operating suite. The attached software permits creation of a database and transmission of information to the laboratory network. One year’s experience has indicated that the quality of reagents and reference substances allows real-time determination of the values of ABB with a high degree of accuracy and reproducibility at a patient’s bed. 

  14. Strong Relationships in Acid-Base Chemistry - Modeling Protons Based on Predictable Concentrations of Strong Ions, Total Weak Acid Concentrations, and pCO2

    DEFF Research Database (Denmark)

    Ring, Troels; Kellum, John A

    2016-01-01

    confirmed the relationship between charged species we then examine some of the classical and recent literature concerning the importance of charge balance. We conclude that focusing on the charges which are predictable such as strong ions and total concentrations of weak acids leads to new insights......Understanding acid-base regulation is often reduced to pigeonholing clinical states into categories of disorders based on arterial blood sampling. An earlier ambition to quantitatively explain disorders by measuring production and elimination of acid has not become standard clinical practice....... Seeking back to classical physical chemistry we propose that in any compartment, the requirement of electroneutrality leads to a strong relationship between charged moieties. This relationship is derived in the form of a general equation stating charge balance, making it possible to calculate [H+] and p...

  15. School-Based Home Instruction and Learning: A Quantitative Synthesis.

    Science.gov (United States)

    Graue, M. Elizabeth; And Others

    1983-01-01

    Research on elementary school-based programs for increasing the educationally stimulating qualities of the home environment was statistically synthesized in a qualitative analysis of 29 controlled studies. Of 121 comparisons made in the analysis, 91.1 percent favored treatment over control groups, thus pointing to the effectiveness of these…

  16. Quantitative exposure assessment in community-based studies

    NARCIS (Netherlands)

    Peters, S.M.|info:eu-repo/dai/nl/304822930

    2012-01-01

    Occupational epidemiology focuses on the associations between exposures at the workplace and disease outcomes, essentially concerned with the prevention of disease. Basically two types of studies can be distinguished in occupational epidemiology: industry-based studies which study a population at

  17. Quantitation of homovanillic acid (HVA) and vanillylmandelic acid (VMA) in urine using gas chromatography-mass spectrometry (GC/MS).

    Science.gov (United States)

    Allenbrand, Ryan; Garg, Uttam

    2010-01-01

    Neuroblastoma, in most cases, is characterized by increased production of catecholamines and their metabolites. Laboratory diagnosis and clinical follow-up include the measurement of urinary homovanillic acid (HVA) and vanillylmandelic acid (VMA). In the following procedure, urine samples are diluted to give a creatinine concentration of 2 mg/dL. Deuterated internal standards are added to the diluted urine samples followed by acidification using HCl. Ethyl acetate is used to extract HVA and VMA from the acidified samples, and the extract is dried. The residue is treated with bis-(trimethylsilyl)trifluoroacetamide (BSTFA), 1% trimethylchlorosilane (TMCS), and pyridine to prepare trimethylsilyl derivatives of HVA and VMA. The derivatized samples are injected to into gas-chromatograph mass spectrometer. The concentration of HVA and VMA is determined by comparing responses of unknown sample to the responses of calibrators using selected ion monitoring.

  18. Quantitative determination of carboxylic acids, amino acids, carbohydrates, ethanol and hydroxymethylfurfural in honey by (1)H NMR.

    Science.gov (United States)

    del Campo, Gloria; Zuriarrain, Juan; Zuriarrain, Andoni; Berregi, Iñaki

    2016-04-01

    A method using (1)H NMR spectroscopy has been developed to quantify simultaneously thirteen analytes in honeys without previous separation or pre-concentration steps. The method has been successfully applied to determine carboxylic acids (acetic, formic, lactic, malic and succinic acids), amino acids (alanine, phenylalanine, proline and tyrosine), carbohydrates (α- and β-glucose and fructose), ethanol and hydroxymethylfurfural in eucalyptus, heather, lavender, orange blossom, thyme and rosemary honeys. Quantification was performed by using the area of the signal of each analyte in the honey spectra, together with external standards. The regression analysis of the signal area against concentration plots, used for the calibration of each analyte, indicates a good linearity over the concentration ranges found in honeys, with correlation coefficients higher than 0.985 for the thirteen quantified analytes. The recovery studies give values over the 93.7-105.4% range with relative standard deviations lower than 7.4%. Good precision, with relative standard deviations over the range of 0.78-5.21% is obtained.

  19. Whole-body acid-base modeling revisited

    DEFF Research Database (Denmark)

    Ring, Troels; Nielsen, Søren

    2017-01-01

    The textbook account of whole-body acid-base balance in terms of endogenous acid production, renal net acid excretion and gastrointestinal alkali absorption which is the only comprehensive model around, has never been applied in clinical practice or been formally validated. In order to improve...... understanding of acid-base modeling, we managed to write up this conventional model as an expression solely on urine chemistry. Renal net acid excretion and endogenous acid production was already formulated in terms of urine chemistry, and we could from the literature also see gastrointestinal alkali absorption...

  20. Quantitative analysis of flavonoids and phenolic acids in Arnica montana L. by micellar electrokinetic capillary chromatography.

    Science.gov (United States)

    Ganzera, Markus; Egger, Christoph; Zidorn, Christian; Stuppner, Hermann

    2008-05-01

    Arnica montana preparations have been used in Europe for centuries to treat skin disorders. Among the biologically active ingredients in the flower heads of the plant are sequiterpenes, flavonoids and phenolic acids. For the simultaneous determination of compounds belonging to the latter two groups a micellar electrokinetic capillary chromatography (MEKC) method was developed and validated. By using an electrolyte solution containing 50 mM borax, 25 mM sodium dodecyl sulfate and 30% of acetonitrile the separation of seven flavonoids and four caffeic acid derivatives was feasible in less than 20 min. The optimized system was validated for repeatability (sigma(rel) or = 0.9996), and then successfully applied to assay several plant samples. In all of them the most dominant flavonoid was found to be quercetin 3-O-glucuronic acid, whereas 3,5-dicaffeoylquinic acid was the major phenolic acid; the total content of flavonoids and phenolic acids varied in the samples from 0.60 to 1.70%, and 1.03 to 2.24%, respectively.

  1. Quantitative Determination and Comparison of the Surface Binding of Phosphonic Acid, Carboxylic Acid, and Catechol Ligands on TiO2 Nanoparticles.

    Science.gov (United States)

    Zeininger, Lukas; Portilla, Luis; Halik, Marcus; Hirsch, Andreas

    2016-09-12

    The adsorption, desorption, co-adsorption, and exchange behavior of phosphonic acid, carboxylic acid, and catechol derivatives on the surface of titanium oxide (anatase) nanoparticles are investigated. Thermogravimetric analysis provides a facile and fast-track quantitative determination of the wet-chemical monolayer adsorption constants and grafting densities of ten adsorbates, all under neutral pH conditions. This characterization protocol allows straightforward quantification of the relevant thermodynamic data of ligand adsorption and a comparison of ligand adsorption strengths. The reported procedure is proposed as a universal tool and it should be applicable to many other colloidal metal oxide materials. Moreover, the determined values for the adsorption constants and the monolayer grafting densities provide a toolbox for the assessment of the adsorbates' behavior in desorption, exchange, and co-adsorption equilibria. This versatile evaluation procedure will help to identify optimal monolayer-surface combinations and to evaluate critical parameters, such as monolayer robustness, ligand exchange rates, or targeted mixed assembly of functionalities.

  2. Magnetic Resonance-based Motion Correction for Quantitative PET in Simultaneous PET-MR Imaging.

    Science.gov (United States)

    Rakvongthai, Yothin; El Fakhri, Georges

    2017-07-01

    Motion degrades image quality and quantitation of PET images, and is an obstacle to quantitative PET imaging. Simultaneous PET-MR offers a tool that can be used for correcting the motion in PET images by using anatomic information from MR imaging acquired concurrently. Motion correction can be performed by transforming a set of reconstructed PET images into the same frame or by incorporating the transformation into the system model and reconstructing the motion-corrected image. Several phantom and patient studies have validated that MR-based motion correction strategies have great promise for quantitative PET imaging in simultaneous PET-MR. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. [A new SVRDF 3D-descriptor of amino acids and its application to peptide quantitative structure activity relationship].

    Science.gov (United States)

    Tong, Jian-Bo; Zhang, Sheng-Wan; Cheng, Su-Li; Li, Gai-Xian

    2007-01-01

    To establish a new amino acid structure descriptor that can be applied to polypeptide quantitative structure activity relationship (QSAR) studies, a new descriptor, SVRDF, was derived from a principal components analysis of a matrix of 150 radial distribution function index of amino acids. The scale was then applied in three panels of peptide QSAR that were molded by partial least squares regression. The obtained models with the correlation coefficients (R2(cum)), cross-validation correlation coefficients (Q2(cum)) were 0.766 and 0.724 for 48 bitter tasting dipeptides; 0.941 and 0.811 for 21 oxytocin analogues; 0.996 and 0.919 for 20 thromboplastin inhibitors. Satisfactory results showed that information related to biological activity can be systemically expressed by SVRDF scales, which may be an useful structural expression methodology for the study of peptides QSAR.

  4. Acid-base bifunctional catalytic surfaces for nucleophilic addition reactions.

    Science.gov (United States)

    Motokura, Ken; Tada, Mizuki; Iwasawa, Yasuhiro

    2008-09-01

    This article illustrates the modification of oxide surfaces with organic amine functional groups to create acid-base bifunctional catalysts, summarizing our previous reports and also presenting new data. Immobilization of organic amines as bases on inorganic solid-acid surfaces afforded highly active acid-base bifunctional catalysts, which enabled various organic transformations including C--C coupling reactions, though these reactions did not proceed with either the homogeneous amine precursors or the acidic supports alone. Spectroscopic characterization, such as by solid-state MAS NMR and FTIR, revealed not only the interactions between acidic and basic sites but also bifunctional catalytic reaction mechanisms.

  5. Quantitative analysis of total flavonoids and total phenolic acids in thirty Hypericum taxa.

    Science.gov (United States)

    Pilepić, Kroata Hazler; Males, Zeljan; Crkvencić, Maja

    2013-03-01

    The content of total flavonoids and total phenolic acids in the aerial parts of thirty Hypericum taxa collected over two consecutive seasons was investigated by spectrophotometric methods. All taxa examined contained flavonoids and phenolic acids in different quantities, although the differences between species and year's harvest were not found to be significant. The quantity of total flavonoids ranged from 0.1 to 1.6%. The highest content of flavonoids was found in the samples of H. japonicum (1.6%) and H. perforatum (1.5%), while the samples of H. androsaemum and H. balearicum comprised the lowest flavonoid amount (0.13%). The content of total phenolic acids in the investigated samples was found to be between 1.1-10.4%. The samples of H. perforatum were found to contain the highest quantity of phenolic acids (10.4% and 10.2%), whereas the sample ofH. linarifolium showed the lowest amount of phenolic acids (1.1%).

  6. Direct electrospray ionization mass spectrometry quantitative analysis of sebacic and terephthalic acids in biodegradable polymers.

    Science.gov (United States)

    Rizzarelli, Paola; Zampino, Daniela; Ferreri, Loredana; Impallomeni, Giuseppe

    2011-02-01

    A direct, rapid, and easy electrospray ionization mass spectrometry (ESI-MS) method to determine concentrations of sebacic acid (SA) and terephthalic acid (TA) residues in biodegradable copolymers was developed. Copolyester samples were synthesized from 1,4-butanediol and sebacic and terephthalic acids by melt polymerization. Extraction of monomers was performed in methanol. Their concentrations were determined by direct infusion ESI-MS, without chromatographic separation, using 1,12-dodecanedioic acid (DDA) as an internal standard. Calibration curves were obtained by plotting the ratio of the areas of the peaks relative to monomers and DDA standard as a function of their concentration ratio. We validated the method by determining the concentration of TA residue using both the ESI-MS protocol and high-performance liquid chromatography (HPLC) analysis with UV detection. The linearity range and the detection limit of this assay were 0.1-5.0 and 0.01 ppm for SA and 0.1-6.0 and 0.03 ppm for TA. This assay represents a useful alternative to conventional methods currently employed for acid quantification, resulting advantageous for its speed and high sensitivity.

  7. Development and Evaluation of a Multimedia e-Learning Resource for Electrolyte and Acid-Base Disorders

    Science.gov (United States)

    Davids, Mogamat Razeen; Chikte, Usuf M. E.; Halperin, Mitchell L.

    2011-01-01

    This article reports on the development and evaluation of a Web-based application that provides instruction and hands-on practice in managing electrolyte and acid-base disorders. Our teaching approach, which focuses on concepts rather than details, encourages quantitative analysis and a logical problem-solving approach. Identifying any dangers to…

  8. A microcomputer-based system for quantitative petrographic analysis

    Science.gov (United States)

    Starkey, John; Samantaray, Abani Kanta

    1994-11-01

    An imaging system based on a videocamera and frame grabber is described which is capable of capturing and analyzing composite images. Individual images are captured interactively, this permits manipulation of the illumination to emphasize selected features of interest in sequentially captured images. Data from the sequential images are accumulated to form a synoptic image, which allows analysis to proceed in a manner which emulates the techniques of manual, polarized light microscopy. The effects of rotating a thin section in plane and crossed polarized light can be simulated so that mineral boundaries can be detected across which there is a lack of contrast at some orientations. The imaging system implements algorithms for digital filtering and boundary identification and incorporates facilities for image editing. Mathematical functions are provided for the interpolation of boundaries which are not detected in their entirety, in a way analogous to visual interpretation. The image data are written to 256-color PCX image files which can be manipulated by other software or transmitted electronically. The locations of the boundaries of the features of interest are available as lists of ( x, y) coordinates and as chain codes. From these the size, shape, and spatial parameters are computed. In addition, the gray-level and segmented images are used to obtain texture information. The imaging system is illustrated by application to the analysis of grain boundaries, modal composition, and grain shapes in petrographic thin sections. The analytical results are compared with results obtained by traditional petrographic analyses.

  9. Quantitative and Sensitive RNA Based Detection of Bacillus Spores

    Directory of Open Access Journals (Sweden)

    Ekaterina eOsmekhina

    2014-03-01

    Full Text Available The fast and reliable detection of bacterial spores is of great importance and still remains a challenge. Here we describe a direct RNA based diagnostic method for the specific detection of viable bacterial spores which does not depends on an enzymatic amplification step and therefore is directly appropriate for quantification. The procedure includes the following steps: (i heat activation of spores, (ii germination and enrichment cultivation, (iii cell lysis, and (iv analysis of 16S rRNA in crude cell lysates using a sandwich hybridization assay. The sensitivity of the method is dependent on the cultivation time and the detection limit; it is possible to detect 10 spores per ml when the RNA analysis is performed after 6 h of enrichment cultivation. At spore concentrations above 106 spores per ml the cultivation time can be shortened to 30 min. Total analysis times are in the range of 2 to 8 hours depending on the spore concentration in samples. The developed procedure is optimized at the example of Bacillus subtilis spores but should be applicable to other organisms. The new method can easily be modified for other target RNAs and is suitable for specific detection of spores from known groups of organisms.

  10. Specific catalysis of asparaginyl deamidation by carboxylic acids: kinetic, thermodynamic, and quantitative structure-property relationship analyses.

    Science.gov (United States)

    Connolly, Brian D; Tran, Benjamin; Moore, Jamie M R; Sharma, Vikas K; Kosky, Andrew

    2014-04-07

    Asparaginyl (Asn) deamidation could lead to altered potency, safety, and/or pharmacokinetics of therapeutic protein drugs. In this study, we investigated the effects of several different carboxylic acids on Asn deamidation rates using an IgG1 monoclonal antibody (mAb1*) and a model hexapeptide (peptide1) with the sequence YGKNGG. Thermodynamic analyses of the kinetics data revealed that higher deamidation rates are associated with predominantly more negative ΔS and, to a lesser extent, more positive ΔH. The observed differences in deamidation rates were attributed to the unique ability of each type of carboxylic acid to stabilize the energetically unfavorable transition-state conformations required for imide formation. Quantitative structure property relationship (QSPR) analysis using kinetic data demonstrated that molecular descriptors encoding for the geometric spatial distribution of atomic properties on various carboxylic acids are effective determinants for the deamidation reaction. Specifically, the number of O-O and O-H atom pairs on carboxyl and hydroxyl groups with interatomic distances of 4-5 Å on a carboxylic acid buffer appears to determine the rate of deamidation. Collectively, the results from structural and thermodynamic analyses indicate that carboxylic acids presumably form multiple hydrogen bonds and charge-charge interactions with the relevant deamidation site and provide alignment between the reactive atoms on the side chain and backbone. We propose that carboxylic acids catalyze deamidation by stabilizing a specific, energetically unfavorable transition-state conformation of l-asparaginyl intermediate II that readily facilitates bond formation between the γ-carbonyl carbon and the deprotonated backbone nitrogen for cyclic imide formation.

  11. Sensitive and rapid method for amino acid quantitation in malaria biological samples using AccQ.Tag ultra performance liquid chromatography-electrospray ionization-MS/MS with multiple reaction monitoring.

    Science.gov (United States)

    Armenta, Jenny M; Cortes, Diego F; Pisciotta, John M; Shuman, Joel L; Blakeslee, Kenneth; Rasoloson, Dominique; Ogunbiyi, Oluwatosin; Sullivan, David J; Shulaev, Vladimir

    2010-01-15

    An AccQ*Tag ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (AccQ*Tag-UPLC-ESI-MS/MS) method for fast, reproducible, and sensitive amino acid quantitation in biological samples, particularly, the malaria parasite Plasmodium falciparum is presented. The Waters Acquity TQD UPLC/MS system equipped with a photodiode array (PDA) detector was used for amino acid separation and detection. The method was developed and validated using amino acid standard mixtures containing acidic, neutral, and basic amino acids. For MS analysis, the optimum cone voltage implemented, based on direct infusion analysis of a few selected AccQ*Tag amino acids with multiple reaction monitoring, varied from 29 to 39 V, whereas the collision energy varied from 15 to 35 V. Calibration curves were built using both internal and external standardization. Typically, a linear response for all amino acids was observed at concentration ranges of 3 x 10(-3)-25 pmol/muL. For some amino acids, concentration limits of detection were as low as 1.65 fmol. The coefficients of variation for retention times were within the range of 0.08-1.08%. The coefficients of variation for amino acid quantitation, determined from triplicate UPLC-MS/MS runs, were below 8% on the average. The developed AccQ*Tag-UPLC-ESI-MS/MS method revealed good technical and biological reproducibility when applied to P. falciparum and human red blood cells samples. This study should provide a valuable insight into the performance of UPLC-ESI-MS/MS for amino acid quantitation using AccQ*Tag derivatization.

  12. Evaluation of quantitative accuracy in CZT-based pre-clinical SPECT for various isotopes

    Science.gov (United States)

    Park, S.-J.; Yu, A. R.; Kim, Y.-s.; Kang, W.-S.; Jin, S. S.; Kim, J.-S.; Son, T. J.; Kim, H.-J.

    2015-05-01

    In vivo pre-clinical single-photon emission computed tomography (SPECT) is a valuable tool for functional small animal imaging, but several physical factors, such as scatter radiation, limit the quantitative accuracy of conventional scintillation crystal-based SPECT. Semiconductor detectors such as CZT overcome these deficiencies through superior energy resolution. To our knowledge, little scientific information exists regarding the accuracy of quantitative analysis in CZT-based pre-clinical SPECT systems for different isotopes. The aim of this study was to assess the quantitative accuracy of CZT-based pre-clinical SPECT for four isotopes: 201Tl, 99mTc, 123I, and 111In. The quantitative accuracy of the CZT-based Triumph X-SPECT (Gamma-Medica Ideas, Northridge, CA, U.S.A.) was compared with that of a conventional SPECT using GATE simulation. Quantitative errors due to the attenuation and scatter effects were evaluated for all four isotopes with energy windows of 5%, 10%, and 20%. A spherical source containing the isotope was placed at the center of the air-or-water-filled mouse-sized cylinder phantom. The CZT-based pre-clinical SPECT was more accurate than the conventional SPECT. For example, in the conventional SPECT with an energy window of 10%, scatter effects degraded quantitative accuracy by up to 11.52%, 5.10%, 2.88%, and 1.84% for 201Tl, 99mTc, 123I, and 111In, respectively. However, with the CZT-based pre-clinical SPECT, the degradations were only 9.67%, 5.45%, 2.36%, and 1.24% for 201Tl, 99mTc, 123I, and 111In, respectively. As the energy window was increased, the quantitative errors increased in both SPECT systems. Additionally, the isotopes with lower energy of photon emissions had greater quantitative error. Our results demonstrated that the CZT-based pre-clinical SPECT had lower overall quantitative errors due to reduced scatter and high detection efficiency. Furthermore, the results of this systematic assessment quantifying the accuracy of these SPECT

  13. Quantitative milk genomics: estimation of variance components and prediction of fatty acids in bovine milk

    DEFF Research Database (Denmark)

    Krag, Kristian

    The composition of bovine milk fat, used for human consumption, is far from the recommendations for human fat nutrition. The aim of this PhD was to describe the variance components and prediction probabilities of individual fatty acids (FA) in bovine milk, and to evaluate the possibilities...

  14. Quantitation of fatty acids, sterols, and tocopherols in turpentine (Pistacia terebinthus Chia) growing wild in Turkey.

    Science.gov (United States)

    Matthäus, Bertrand; Ozcan, Mehmet Musa

    2006-10-04

    The chemical composition (fatty acids, tocopherols, and sterols) of the oil from 14 samples of turpentine (Pistacia terebinthus L.) fruits is presented in this study. The oil content of the samples varied in a relatively small range between 38.4 g/100 g and 45.1 g/100 g. The dominating fatty acid of the oil is oleic acid, which accounted for 43.0 to 51.3% of the total fatty acids. The total content of vitamin E active compounds in the oils ranged between 396.8 and 517.7 mg/kg. The predominant isomers were alpha- and gamma-tocopherol, with approximate equal amounts between about 110 and 150 mg/kg. The seed oil of P. terebinthus also contained different tocotrienols, with gamma-tocotrienol as the dominate compound of this group, which amounted to between 79 and 114 mg/kg. The total content of sterols of the oils was determined to be between 1341.3 and 1802.5 mg/kg, with beta-sitosterol as the predominent sterol that accounted for more than 80% of the total amount of sterols. Other sterols in noteworthy amounts were campesterol, Delta5-avenasterol, and stigmasterol, which came to about 3-5% of the total sterols.

  15. ACID-BASE INTERACTIONS BETWEEN POLYMERS AND FILLERS

    Institute of Scientific and Technical Information of China (English)

    WANG Qingguo; CHEN Fute; HUANG Yuanfu; ZHOU Qingli

    1987-01-01

    Inverse gas chromatography(IGC) and Fourier-transform infrared (FT-IR) techniques were applied to determining the relative acid-base strength of polymers and coupling agents. The acid-base characteristics of fillers such as CaCO3 could be altered by treatment with different coupling agents. It was shown that some mechanical properties of filled polymers were obviously associated with acid-base interactions between polymers and fillers.

  16. A Quantitative Corpus-Based Approach to English Spatial Particles: Conceptual Symmetry and Its Pedagogical Implications

    Science.gov (United States)

    Chen, Alvin Cheng-Hsien

    2014-01-01

    The present study aims to investigate how conceptual symmetry plays a role in the use of spatial particles in English and to further examine its pedagogical implications via a corpus-based evaluation of the course books in senior high schools in Taiwan. More specifically, we adopt a quantitative corpus-based approach to investigate whether bipolar…

  17. Characterization of sweet cassava accessions based on molecular, quantitative and qualitative data

    Directory of Open Access Journals (Sweden)

    Eduardo Alano Vieira

    2011-01-01

    Full Text Available The purpose of this study was to estimate the genetic divergence in sweet cassava accessions by molecular markersand quantitative and qualitative characters, as well as determine the correlation between these estimates. Sixteen sweet cassavaaccessions of the Regional Cassava Germplasm Bank of the Cerrado were evaluated under field conditions, for 13 quantitative and33 qualitative characters. In the laboratory, the accessions were evaluated with RAPD markers. Subsequently, matrixes of geneticdissimilarity/distance among the accessions were estimated based on molecular markers and quantitative and qualitative characters.Besides, the significance of the correlation between the matrixes was estimated. The RAPD, qualitative and quantitative dataindicated the existence of high divergence among the accessions. The divergences estimated by molecular markers and by quantitativetraits were weakly associated with each other and moderately with the divergence estimated by qualitative characters.

  18. The Concept of Density Functional Theory Based Descriptors and its Relation with the Reactivity of Molecular Systems: A Semi-Quantitative Study

    Directory of Open Access Journals (Sweden)

    Sourav Pal

    2002-04-01

    Full Text Available Abstract: In this present paper, we have made an attempt to explain the theoretical basis for the empirical hardness/softness concepts to address the reactivity of molecular complexes in a semi-quantitative way within the framework of density functional theory. A model based on local hard-soft-acid-base principle has been proposed. The results obtained using some prototype charge transfer complexes, Lewis acid-base complexes and hydrogen-bonded complexes as examples, are in good agreement with the standard ab initio values. Although the model contains ad hoc parameters, it may form the basis of semi-quantitative description of inter-molecular interactions using hardness/softness parameters. The limitation, weakness and other critical issues of the present model are also discussed.

  19. Acid-base strengths in pyridine

    NARCIS (Netherlands)

    Bos, M.; Dahmen, E.A.M.F.

    1971-01-01

    Although pyridine is a solvent with a low dielectric constant, spectrophotometric determinations show simple dissociation without ion pairs as intermediates for some sulfonphthaleins and polynitrophenols in pyridine. The salts of a number of amines and hydrochloric acid, perchloric acid and picric

  20. Quinoline based receptor in fluorometric discrimination of carboxylic acids

    Directory of Open Access Journals (Sweden)

    2008-12-01

    Full Text Available Quinoline and naphthalene-based fluororeceptors 1 and 2 have been designed and synthesized for detection of hydroxy carboxylic acids in less polar solvents. The receptor 1 shows monomer emission quenching followed by excimer emission upon hydrogen bond-mediated complexation of carboxylic acids. The excimer emission distinguishes aromatic dicarboxylic acids from aliphatic dicarboxylic acids and even long chain aliphatic dicarboxylic acids from short chain aliphatic dicarboxylic acids. The receptor 1 is found to be selective for citric acid with a strong excimer emission in CHCl3. On the contrary, the receptor 2 exhibited less binding constant value and did not form any excimer upon complexation with the same acids under similar conditions. This established the role of quinoline ring nitrogen in binding with the acids.

  1. Enhanced Acid/Base Catalysis in High Temperature Liquid Water

    Institute of Scientific and Technical Information of China (English)

    Xiu Yang LU; Qi JING; Zhun LI; Lei YUAN; Fei GAO; Xin LIU

    2006-01-01

    Two novel and environmentally benign solvent systems, organic acids-enriched high temperature liquid water (HTLW) and NH3-enriched HTLW, were developed, which can enhance the reaction rate of acid/base-catalyzed organic reactions in HTLW. We investigated the decomposition of fructose in organic acids-enriched HTLW, hydrolysis of cinnamaldehyde and aldol condensation of phenylaldehyde with acetaldehyde in NH3-enriched HTLW. The experimental results demonstrated that organic acids-enriched or NH3-enriched HTLW can greatly accelerate acid/base-catalyzed organic reactions in HTLW.

  2. Recognition of Nucleic Acid Junctions Using Triptycene-Based Molecules

    OpenAIRE

    Barros, Stephanie A.; Chenoweth, David M.

    2014-01-01

    Nucleic acid modulation by small molecules is an essential process across the kingdoms of life. Targeting nucleic acids with small molecules represents a significant challenge at the forefront of chemical biology. Nucleic acid junctions are ubiquitous structural motifs in nature and in designed materials. Herein, we describe a new class of structure specific nucleic acid junction stabilizers based on a triptycene scaffold. Triptycenes provide significant stabilization of DNA and RNA three-way...

  3. History of medical understanding and misunderstanding of Acid base balance.

    Science.gov (United States)

    Aiken, Christopher Geoffrey Alexander

    2013-09-01

    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.

  4. Aqueous-phase quantitative NMR determination of amino acid enantiomer ratio by 13C-NMR using chiral neodymium shift reagent.

    Science.gov (United States)

    Florini, Nicola; Faglioni, Francesco; Zucchi, Claudia; Caglioti, Luciano; Pályi, Gyula

    2010-05-01

    A neodymium-(S)-PDTA (PDTA = N,N,N',N'-tetrakis[(hydroxycarbonyl)methyl]-1,2-diaminopropane) complex was found exceptionally useful in the quantitative determination of enantiomer ratios of water-soluble natural amino acids by (13)C-NMR. The method is demonstrated on mixtures of L- and D-enantiomers of various amino acids. The interactions of the chiral shift reagent with the amino acid molecules were rationalized by molecular orbital calculations.

  5. Real time monitoring of nucleic acids ligation based on molecular beacon

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel method has been developed to monitor the nucleic acids ligation process. Molecular beacon was employed here to convert the ligation information into fluorescence signal quickly and quantitatively. This method provides effective and original approach to researching the dynamic ligation process and the interactions between nucleic acids and ligase. An analytical method for T4 DNA ligase based on this way has been built up with a linear detection range from 2.3×10?4 U/mL to 0.23 U/mL. It is rapid and sensitive to detect 2.8×10?5 U T4 DNA ligase in 10 min.

  6. Quantitative Leaching of a Spent Cell Phone Printed Circuit Board by Hydrochloric acid

    Directory of Open Access Journals (Sweden)

    Alafara A. Baba

    2014-07-01

    Full Text Available This paper presents a kinetic data on the hydrometallurgical recovery of some metal ions from a printed circuit board (PCB of a spent cell phone by hydrochloric acid leaching. The effects of acid concentration, temperature and particle diameter on the dissolution efficiency at various leaching time intervals were examined. The results of the leaching investigations showed that the powdered cell phone dissolution increases with increasing acid concentration, system temperature with decreasing particle diameter at 360 rpm. With 2M HCl solution, about 88.49% of the sample was dissolved within 120 minutes using 0.075-0.112 mm particle diameter at 800 C. The results of the study indicated that the dissolution reaction could be represented by a shrinking core model with surface chemical reaction. A value of 0.61, 60.67 kJ/mol and 12.9s-1 were calculated as reaction order, activation energy and frequency factor, respectively for the dissolution process.

  7. Chip-based sequencing nucleic acids

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Neil Reginald

    2014-08-26

    A system for fast DNA sequencing by amplification of genetic material within microreactors, denaturing, demulsifying, and then sequencing the material, while retaining it in a PCR/sequencing zone by a magnetic field. One embodiment includes sequencing nucleic acids on a microchip that includes a microchannel flow channel in the microchip. The nucleic acids are isolated and hybridized to magnetic nanoparticles or to magnetic polystyrene-coated beads. Microreactor droplets are formed in the microchannel flow channel. The microreactor droplets containing the nucleic acids and the magnetic nanoparticles are retained in a magnetic trap in the microchannel flow channel and sequenced.

  8. Chip-based sequencing nucleic acids

    Science.gov (United States)

    Beer, Neil Reginald

    2014-08-26

    A system for fast DNA sequencing by amplification of genetic material within microreactors, denaturing, demulsifying, and then sequencing the material, while retaining it in a PCR/sequencing zone by a magnetic field. One embodiment includes sequencing nucleic acids on a microchip that includes a microchannel flow channel in the microchip. The nucleic acids are isolated and hybridized to magnetic nanoparticles or to magnetic polystyrene-coated beads. Microreactor droplets are formed in the microchannel flow channel. The microreactor droplets containing the nucleic acids and the magnetic nanoparticles are retained in a magnetic trap in the microchannel flow channel and sequenced.

  9. Quantitation of alpha-linolenic acid elongation to eicosapentaenoic and docosahexaenoic acid as affected by the ratio of n6/n3 fatty acids

    Directory of Open Access Journals (Sweden)

    Somoza Veronika

    2009-02-01

    Full Text Available Abstract Background Conversion of linoleic acid (LA and alpha-linolenic acid (ALA to their higher chain homologues in humans depends on the ratio of ingested n6 and n3 fatty acids. Design and methods In order to determine the most effective ratio with regard to the conversion of ALA to eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA, human hepatoma cells were incubated with varying ratios of [13C] labeled linoleic acid ([13C]LA- and alpha-linolenic acid ([13C]ALA-methylesters. Regulative cellular signal transduction pathways involved were studied by determinations of transcript levels of the genes encoding delta-5 desaturase (D5D and delta-6 desaturase (D6D, peroxisome proliferator-activated receptor alpha (PPARα and sterol regulatory element binding protein 1c (SREBP-1c. Mitogen-activated protein kinase kinase 1 (MEK1 and mitogen-activated protein kinase kinase kinase 1 (MEKK1 were also examined. Results Maximum conversion was observed in cells incubated with the mixture of [13C]LA/[13C]ALA at a ratio of 1:1, where 0.7% and 17% of the recovered [13C]ALA was converted to DHA and EPA, respectively. Furthermore, differential regulation of enzymes involved in the conversion at the transcript level, dependent on the ratio of administered n6 to n3 fatty acids in human hepatocytes was demonstrated. Conclusion Formation of EPA and DHA was highest at an administered LA/ALA ratio of 1:1, although gene expression of PPARα, SREBP-1c and D5D involved in ALA elongation were higher in the presence of ALA solely. Also, our findings suggest that a diet-induced enhancement of the cell membrane content of highly unsaturated fatty acids is only possible up to a certain level.

  10. Raman Spectroscopy of Fish Oil Capsules: Polyunsaturated Fatty Acid Quantitation Plus Detection of Ethyl Esters and Oxidation.

    Science.gov (United States)

    Killeen, Daniel P; Marshall, Susan N; Burgess, Elaine J; Gordon, Keith C; Perry, Nigel B

    2017-05-03

    Fish oils are the primary dietary source of ω-3 polyunsaturated fatty acids (PUFA), but these compounds are prone to oxidation, and commercial fish oil supplements sometimes contain less PUFA than claimed. These supplements are predominantly sold in softgel capsules. In this work, we show that Fourier transform (FT)-Raman spectra of fish oils (n = 5) and ω-3 PUFA concentrates (n = 6) can be acquired directly through intact softgel (gelatin) capsules. These spectra could be used to rapidly distinguish supplements containing ethyl esters from those containing triacylglyceride oils. Raman spectroscopy calibrated with partial least-squares regression against traditional fatty acid methyl ester analyses by gas chromatography-mass spectrometry could be used to rapidly and nondestructively quantitate PUFA and other fatty acid classes directly though capsules. We also show that FT-Raman spectroscopy can noninvasively detect oxidation with high sensitivity. Oils with peroxide values of as low as 10 mequiv kg(-1), which are on the cusp of falling outside of specification, could be readily distinguished from oils that were within specification (7 mequiv kg(-1)).

  11. Quantitative determination of caffeine, formic acid, trigonelline and 5-(hydroxymethyl)furfural in soluble coffees by 1H NMR spectrometry.

    Science.gov (United States)

    del Campo, Gloria; Berregi, Iñaki; Caracena, Raúl; Zuriarrain, Juan

    2010-04-15

    A quantitative method for the determination of caffeine, formic acid, trigonelline and 5-(hydroxymethyl)furfural (5-HMF) in soluble coffees by applying the proton nuclear magnetic resonance technique ((1)H NMR) is proposed. Each of these compounds records a singlet signal at the 7.6-9.5 ppm interval of the spectrum, and its area is used to determine the concentration. 3-(Trimethylsilyl)-2,2,3,3-tetradeuteropropionic acid is added in an exact known concentration as a reference for delta=0.00 ppm and as an internal standard. The method is applied to commercial soluble coffees and satisfactorily compared with results obtained by standard methods. The limits of detection and the coefficients of variation (N=10) are, respectively, 1.32 mg/g of solid product and 4.2% for caffeine, 0.45 mg/g and 2.6% for formic acid, 0.58 mg/g and 2.4% for trigonelline, and 0.30 mg/g and 7.3% for 5-HMF. The described method is direct and no previous derivatization is needed.

  12. Putative Alginate Assimilation Process of the Marine Bacterium Saccharophagus degradans 2-40 Based on Quantitative Proteomic Analysis.

    Science.gov (United States)

    Takagi, Toshiyuki; Morisaka, Hironobu; Aburaya, Shunsuke; Tatsukami, Yohei; Kuroda, Kouichi; Ueda, Mitsuyoshi

    2016-02-01

    Quantitative proteomic analysis was conducted to assess the assimilation processes of Saccharophagus degradans cultured with glucose, pectin, and alginate as carbon sources. A liquid chromatography-tandem mass spectrometry approach was used, employing our unique, long monolithic silica capillary column. In an attempt to select candidate proteins that correlated to alginate assimilation, the production of 23 alginate-specific proteins was identified by statistical analyses of the quantitative proteomic data. Based on the analysis, we propose that S. degradans has an alginate-specific gene cluster for efficient alginate utilization. The alginate-specific proteins of S. degradans were comprised of alginate lyases, enzymes related to carbohydrate metabolism, membrane transporters, and transcription factors. Among them, the short-chain dehydrogenase/reductase Sde_3281 annotated in the alginate-specific cluster showed 4-deoxy-L-erythro-5-hexoseulose uronic acid reductase (DehR) activity. Furthermore, we found two different genes (Sde_3280 and Sde_0939) encoding 2-keto-3-deoxy-D-gluconic acid (KDG) kinases (KdgK) that metabolize the KDG derived from alginate and pectin in S. degradans. S. degradans used Sde_3280 to phosphorylate the KDG derived from alginate and Sde_0939 to phosphorylate the KDG derived from pectin. The distinct selection of KdgKs provides an important clue toward the elucidation of how S. degradans recognizes and processes polysaccharides.

  13. Strong Relationships in Acid-Base Chemistry – Modeling Protons Based on Predictable Concentrations of Strong Ions, Total Weak Acid Concentrations, and pCO2

    Science.gov (United States)

    Kellum, John A.

    2016-01-01

    Understanding acid-base regulation is often reduced to pigeonholing clinical states into categories of disorders based on arterial blood sampling. An earlier ambition to quantitatively explain disorders by measuring production and elimination of acid has not become standard clinical practice. Seeking back to classical physical chemistry we propose that in any compartment, the requirement of electroneutrality leads to a strong relationship between charged moieties. This relationship is derived in the form of a general equation stating charge balance, making it possible to calculate [H+] and pH based on all other charged moieties. Therefore, to validate this construct we investigated a large number of blood samples from intensive care patients, where both data and pathology is plentiful, by comparing the measured pH to the modeled pH. We were able to predict both the mean pattern and the individual fluctuation in pH based on all other measured charges with a correlation of approximately 90% in individual patient series. However, there was a shift in pH so that fitted pH in general is overestimated (95% confidence interval -0.072–0.210) and we examine some explanations for this shift. Having confirmed the relationship between charged species we then examine some of the classical and recent literature concerning the importance of charge balance. We conclude that focusing on the charges which are predictable such as strong ions and total concentrations of weak acids leads to new insights with important implications for medicine and physiology. Importantly this construct should pave the way for quantitative acid-base models looking into the underlying mechanisms of disorders rather than just classifying them. PMID:27631369

  14. Detection of quantitative trait loci affecting the milk fatty acid profile on sheep chromosome 22: role of the stearoyl-CoA desaturase gene in Spanish Churra sheep.

    Science.gov (United States)

    García-Fernández, M; Gutiérrez-Gil, B; García-Gámez, E; Sánchez, J P; Arranz, J J

    2010-01-01

    Sheep milk fat contains several components that may provide human health benefits, such as monounsaturated fatty acids and conjugated linoleic acid (CLA). Most of the CLA in ruminant milk is synthesized in the mammary gland by the action of the enzyme stearoyl-CoA desaturase (SCD) on circulating vaccenic acid (trans-11 C18:2; VA). Previous studies have found significant associations between polymorphisms in the SCD gene and the fatty acid composition of ruminant products, including sheep milk. Based on this, we performed a quantitative trait loci (QTL) analysis of an ovine chromosome (22) that harbors the SCD gene for effects on milk fatty acid composition traits and classical milk production traits. We identified a suggestive QTL influencing the CLA/VA ratio with the maximum statistic at position 26 cM of the studied chromosome, whereas the SCD gene has been mapped to position 41.6 cM. The individual introduction of 4 SCD single nucleotide polymorphisms in the QTL model did not cause a reduction of the variance explained by the QTL, which suggests that the SCD gene is not directly responsible for the detected effect in the Churra population studied herein. This conclusion was supported by the lack of any significant association identified between the 4 SCD single nucleotide polymorphisms and the CLA/VA ratio. This association analysis suggested a possible effect of the SCD gene on milk fat percentage in Churra sheep. An independent confirmation of these primary results will be required before attempting its practical implementation in selection programs.

  15. Ionisation constants of inorganic acids and bases in aqueous solution

    CERN Document Server

    Perrin, D D

    2013-01-01

    Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution, Second Edition provides a compilation of tables that summarize relevant data recorded in the literature up to the end of 1980 for the ionization constants of inorganic acids and bases in aqueous solution. This book includes references to acidity functions for strong acids and bases, as well as details about the formation of polynuclear species. This text then explains the details of each column of the tables, wherein column 1 gives the name of the substance and the negative logarithm of the ionization constant and column 2

  16. Quantitation of Cotinine in Nonsmoker Saliva Using Chip Based Nanoelectrospray Tandem Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tomkins, Bruce A [ORNL; Van Berkel, Gary J [ORNL; Jenkins, Roger A [ORNL; Counts, Richard Wayne [ORNL

    2006-01-01

    A new analytical procedure was developed for the quantitation of nonsmoker salivary cotinine. Small volumes of saliva were diluted with water, fortified with cotinine-d{sub 3} (internal standard), then passed through small extraction columns. The analyte and internal standard were eluted with 0.1% (v/v) acetic acid/acetonitrile. Aliquots of each extract were analyzed directly, without chromatographic separation, using chip-based (NanoMate{sup TM}) nanospray tandem mass spectrometry. The calculated detection limit was 0.49 ng cotinine/mL saliva. This method was used to quantify salivary cotinine collected from nonsmoking human subjects living in one of three environmental tobacco smoke (ETS) exposure categories or 'cells': 1. smoking home/smoking workplace; 2. smoking home/nonsmoking workplace; and 3. nonsmoking home/smoking workplace. Samples were collected during five sequential days, including Saturday, as part of a larger study to evaluate potential variability in exposure to ETS. Salivary cotinine measurements were made for the purpose of excluding misclassified smokers and for comparison with known levels of exposure to airborne nicotine in each exposure category. The concentrations observed were consistent with those reported from other large studies reported elsewhere. A non-parametric statistical test was applied to the data within each cell. No statistically significant differences were found between the mean cotinine concentrations collected on a weekday as compared to those collected on a weekend day. When the non-parametric test was applied to the three cells, a statistically significant difference was observed between cell 1 compared to cells 2 and 3. The salivary cotinine concentrations were thus statistically invariant over a five-day exposure period, and they were greatest under the conditions of smoking home and smoking workplace.

  17. Validation of an Ultraviolet-visible (UV-Vis) technique for the quantitative determination of curcumin in poly(L-lactic acid) nanoparticles.

    Science.gov (United States)

    Silva-Buzanello, Rosana Aparecida da; Ferro, Ana Caroline; Bona, Evandro; Cardozo-Filho, Lúcio; Araújo, Pedro Henrique Hermes de; Leimann, Fernanda Vitória; Gonçalves, Odinei Hess

    2015-04-01

    Curcumin is a natural yellow-orange pigment extracted from turmeric and is a potential substitute of health-dangerous artificial dyes. Nanoencapsulation in biodegradable polymers is a promising alternative to improve curcumin stability and water solubility but curcumin concentration inside the nanoparticles must be precisely known. A reliable method to determine the actual curcumin concentration must be validated since the validation procedures warrant that the method is adequate and sufficient for the specific application involved. This work describes the validation parameters given by the International Conference on Harmonisation (ICH) guidelines to adopt an analytical method based on Ultraviolet-visible spectroscopy for the quantitative determination of curcumin encapsulated in poly(l-lactic acid) nanoparticles. This method was validated in respect to linearity, detection limit, quantification limit, accuracy and precision. Studies on the analytical procedure validation warranted safety in final results obtained for the curcumin concentration in the nanoparticles. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. EXTRACTION AND QUANTITATIVE DETERMINATION OF ASCORBIC ACID FROM BANANA PEEL MUSA ACUMINATA ‘KEPOK’

    Directory of Open Access Journals (Sweden)

    Khairul Anwar Mohamad Said

    2016-04-01

    Full Text Available This paper discusses the extraction of an antioxidant compound, which is ascorbic acid or vitamin C, from a banana peel using an ultrasound-assisted extraction (UAE method. The type of banana used was Musa acuminata also known as “PisangKepok” in Malaysia. The investigation includes the effect of solvent/solid ratio (4.5, 5 g and 10  ml/g, sonication time (15, 30 and 45 mins and temperature variation (30 , 45  and 60oC on the extraction of ascorbic acid compounds from the banana peel to determine the best or optimum condition of the operation. Out of all extract samples analyzed by redox titration method using iodine solution, it was found that the highest yield was 0.04939 ± 0.00080 mg that resulted from an extraction at 30oC for 15 mins with 5 ml/g solvent-to-solute ratio.KEYWORDS:  Musa acuminata; ultrasound-assisted extraction; vitamin C; redox titration

  19. Quantitation of trans-aconitic acid in different stages of the sugar-manufacturing process.

    Science.gov (United States)

    Montoya, Guillermo; Londono, July; Cortes, Paola; Izquierdo, Olga

    2014-08-20

    The sugar cane industry has seen how biomass production in sugar mills would be converted to a readily available source of molecules besides sugar. Properly managed, byproducts would be transformed into a sustainable source of renewable and environmentally friendly chemical products. As a principal and more abundant organic acid in sugar cane juice, trans-aconitic acid (TAA) has been studied for use as a plasticizer in the polymer industry. However, up to now no industrial-scale application has been reported. As a reasonable approach to recover TAA from a sugar mill, first, an analytical method to determine its presence in all stages of the sugar-manufacturing process is needed. A new modern method was developed to measure TAA in seven stages in a sugar mill located in Valle del Cauca, Colombia. The stages with higher content of TAA were syrup, with 3363.6 ± 589.3 mg/L, and honey (molasses), with 6110.05 ± 139.5 mg/L.

  20. Epigastric electrical impedance for the quantitative determination of the gastric acidity.

    Science.gov (United States)

    Giouvanoudi, A C; Spyrou, N M

    2008-11-01

    Electrical impedance measurements have been used by scientists since the 1980s to investigate the gastric function. In this work, these measurements were carried out using the epigastrograph, a device generating alternating current of 32 kHz and injecting it in the gastric area of the human body with surface electrodes, located around the abdominal area. Although the method has been used for about three decades the physiological interpretation of these measurements is still under research. This work states that the electrical impedance measurements from the gastric area depend on the conductivity of the gastric lumen, due mainly to gastric acid secretions and to the conductivity and chemical form of the ingested meal. By choosing the proper test meal the gastric acidity in the empty, healthy stomach was also estimated. The estimated value is in accordance with the literature. The method is non-invasive, relatively inexpensive, simple to medical technologists and subjects, and involves no radiation risk. The method may form the basis for the development of a non-invasive gastric pH meter.

  1. 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.

  2. What is the Ultimate Goal in Acid-Base Regulation?

    Science.gov (United States)

    Balakrishnan, Selvakumar; Gopalakrishnan, Maya; Alagesan, Murali; Prakash, E. Sankaranarayanan

    2007-01-01

    It is common to see chapters on acid-base physiology state that the goal of acid-base regulatory mechanisms is to maintain the pH of arterial plasma and not arterial PCO [subscript 2] (Pa[subscript CO[subscript 2

  3. The Roles of Acids and Bases in Enzyme Catalysis

    Science.gov (United States)

    Weiss, Hilton M.

    2007-01-01

    Many organic reactions are catalyzed by strong acids or bases that protonate or deprotonate neutral reactants leading to reactive cations or anions that proceed to products. In enzyme reactions, only weak acids and bases are available to hydrogen bond to reactants and to transfer protons in response to developing charges. Understanding this…

  4. Disorders of Acid-Base Balance: New Perspectives.

    Science.gov (United States)

    Seifter, Julian L; Chang, Hsin-Yun

    2017-01-01

    Disorders of acid-base involve the complex interplay of many organ systems including brain, lungs, kidney, and liver. Compensations for acid-base disturbances within the brain are more complete, while limitations of compensations are more apparent for most systemic disorders. However, some of the limitations on compensations are necessary to survival, in that preservation of oxygenation, energy balance, cognition, electrolyte, and fluid balance are connected mechanistically. This review aims to give new and comprehensive perspective on understanding acid-base balance and identifying associated disorders. All metabolic acid-base disorders can be approached in the context of the relative losses or gains of electrolytes or a change in the anion gap in body fluids. Acid-base and electrolyte balance are connected not only at the cellular level but also in daily clinical practice. Urine chemistry is essential to understanding electrolyte excretion and renal compensations. Many constructs are helpful to understand acid-base, but these models are not mutually exclusive. Electroneutrality and the close interconnection between electrolyte and acid-base balance are important concepts to apply in acid-base diagnoses. All models have complexity and shortcuts that can help in practice. There is no reason to dismiss any of the present constructs, and there is benefit in a combined approach.

  5. A new representation of acid-base disturbances

    NARCIS (Netherlands)

    M. Hekking (Marcel); E.S. Gelsema; J. Lindemans (Jan)

    1994-01-01

    textabstractThe acid-base status of intensive care patients is monitored on the basis of three quantities. The graphical representation which may be of help for the monitoring task is therefore cumbersome. The classical Siggaard-Andersen acid-base chart is such a representation, but it is only suite

  6. The Roles of Acids and Bases in Enzyme Catalysis

    Science.gov (United States)

    Weiss, Hilton M.

    2007-01-01

    Many organic reactions are catalyzed by strong acids or bases that protonate or deprotonate neutral reactants leading to reactive cations or anions that proceed to products. In enzyme reactions, only weak acids and bases are available to hydrogen bond to reactants and to transfer protons in response to developing charges. Understanding this…

  7. Connecting Acids and Bases with Encapsulation... and Chemistry with Nanotechnology

    Science.gov (United States)

    Criswell, Brett

    2007-01-01

    The features and the development of various new acids and bases activity sets that combines chemistry with nanotechnology are being described. These sets lead to the generation of many nanotechnology-based pharmaceuticals for the treatment of various diseases.

  8. Connecting Acids and Bases with Encapsulation... and Chemistry with Nanotechnology

    Science.gov (United States)

    Criswell, Brett

    2007-01-01

    The features and the development of various new acids and bases activity sets that combines chemistry with nanotechnology are being described. These sets lead to the generation of many nanotechnology-based pharmaceuticals for the treatment of various diseases.

  9. Quantitative determination of amorphous nicardipine hydrochloride in long acting formula (NIC-LA) using light anhydrous silicic acid.

    Science.gov (United States)

    Kohinata, Takeru; Fujii, Mitsuo; Nakamura, Souichiro; Hamada, Noritaka; Yonemochi, Etsuo; Terada, Katsuhide

    2004-12-01

    We investigated a method to quantitatively determine amorphous nicardipine hydrochloride (NIC) in the NIC-long acting formula (LA) model formulas prepared using NIC, light anhydrous silicic acid (LASA) and carboxymethylethylcellulose (CMEC). Consequently, since the quantity of total NIC in the formula can be determined by means of HPLC and crystal NIC can be determined by the differential scanning calorimetry (DSC) method because the heat of fusion (85.08 J/g) of NIC is constant and unaffected by excipients, we developed the HPLC-DSC method by which the quantity of amorphous NIC is calculated as the difference between the quantity of total NIC determined by HPLC and the quantity of crystal NIC determined by DSC. This practical HPLC-DSC method was confirmed to have good accuracy and reproducibility.

  10. EXTRACTION AND SORPTION BENZOIC ACID FROM AQUEOUS SOLUTIONS OF POLYMERS BASED ON N-VINYLAMIDES

    Directory of Open Access Journals (Sweden)

    A. G. Savvina

    2015-01-01

    Full Text Available The widespread use of aromatic acids (benzoic acid, salicylic as preservatives necessitates their qualitative and quantitative determination in food. Effective and common way to separation and concentration of aromatic acids liquid extraction. Biphasic system of water-soluble polymers based on (poly-N-vinyl pyrrolidone, and poly-N-vinylcaprolactam satisfy the requirements of the extraction system. When sorption concentration improved definition of the metrological characteristics, comply with the requirements for sensitivity and selectivity definition appears possible, use of inexpensive and readily available analytical equipment. When studying the adsorption of benzoic acid used as a sorbent crosslinked polymer based on N-vinyl pyrrolidone, obtained by radical polymerisation of a functional monomer and crosslinker. In the extraction of benzoic acid to maximize the allocation of water and the organic phase of the polymer used salt solutions with concentrations close to saturation. Regardless of the nature of the anion salt is used as salting-out agent, aromatic acids sorption increases with the size of the cations. In the experiment the maximum recovery rate (80% benzoic acid obtained in the PVP (0.2 weight%. Ammonium sulphate. The dependence stepepni benzoic acid extraction from time sorption sorbent mass and the pH of the aqueous phase. To establish equilibrium in the system, for 20 minutes. The dependence of the degree of extraction of the acid pH indicates that the acid is extracted into the molecular form. The maximum adsorption is reached at pH 3,5, with its efficiency decreases symbatically reduce the amount of undissociated acid molecules in solution.

  11. Simultaneous quantitation of urinary cotinine and acrylonitrile-derived mercapturic acids with ultraperformance liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    Wu, Chia-Fang; Uang, Shi-Nian; Chiang, Su-Yin; Shih, Wei-Chung; Huang, Yu-Fang; Wu, Kuen-Yuh

    2012-02-01

    Acrylonitrile (AN), a widely used industrial chemical also found in tobacco smoke, has been classified as a possible human carcinogen (group 2B) by the International Agency for Research on Cancer. AN can be detoxified by glutathione S-transferase (GST) to form glutathione (GSH) conjugates in vivo. It can be metabolically activated by cytochrome P450 2E1 to form 2-cyanoethylene oxide, which can also be detoxified by GST to generate GSH conjugates. The GSH conjugates can be further metabolized to mercapturic acids (MAs), namely, N-acetyl-S-(2-cyanoethyl)cysteine (CEMA), N-acetyl-S-(2-hydroxyethyl)cysteine (HEMA), and N-acetyl-S-(1-cyano-2-hydroxyethyl)cysteine (CHEMA). This study developed an ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) method to quantitatively profile the major AN urinary metabolites (CEMA, HEMA, and CHEMA) to assess AN exposure, as well as analyze urinary cotinine (COT) as an indicator for tobacco smoke exposure. The limits of quantitation were 0.1, 0.1, 1.0, and 0.05 μg/L for HEMA, CEMA, CHEMA, and COT, respectively. This method was applied to analyze the three AN-derived MAs in 36 volunteers with no prior occupational AN exposure. Data analysis showed significant correlations between the level of COT and the levels of these MAs, suggesting them as biomarkers for exposure to low levels of AN. The results demonstrate that a highly specific and sensitive UPLC-MS/MS method has been successfully developed to quantitatively profile the major urinary metabolites of AN in humans to assess low AN exposure.

  12. Real-Time Quantitative Analysis of Valproic Acid in Exhaled Breath by Low Temperature Plasma Ionization Mass Spectrometry

    Science.gov (United States)

    Gong, Xiaoxia; Shi, Songyue; Gamez, Gerardo

    2017-04-01

    Real-time analysis of exhaled human breath is a rapidly growing field in analytical science and has great potential for rapid and noninvasive clinical diagnosis and drug monitoring. In the present study, an LTP-MS method was developed for real-time, in-vivo and quantitative analysis of γ-valprolactone, a metabolite of valproic acid (VPA), in exhaled breath without any sample pretreatment. In particular, the effect of working conditions and geometry of the LTP source on the ions of interest, protonated molecular ion at m/z 143 and ammonium adduct ion at m/z 160, were systematically characterized. Tandem mass spectrometry (MS/MS) with collision-induced dissociation (CID) was carried out in order to identify γ-valprolactone molecular ions ( m/z 143), and the key fragment ion ( m/z 97) was used for quantitation. In addition, the fragmentation of ammonium adduct ions to protonated molecular ions was performed in-source to improve the signal-to-noise ratio. At optimum conditions, signal reproducibility with an RSD of 8% was achieved. The concentration of γ-valprolactone in exhaled breath was determined for the first time to be 4.83 (±0.32) ng/L by using standard addition method. Also, a calibration curve was obtained with a linear range from 0.7 to 22.5 ng/L, and the limit of detection was 0.18 ng/L for γ-valprolactone in standard gas samples. Our results show that LTP-MS is a powerful analytical platform with high sensitivity for quantitative analysis of volatile organic compounds in human breath, and can have potential applications in pharmacokinetics or for patient monitoring and treatment.

  13. Higher body mass, older age and higher monounsaturated fatty acids intake reflect better quantitative ultrasound parameters in Inuit preschoolers

    Directory of Open Access Journals (Sweden)

    Jessy El Hayek

    2012-07-01

    Full Text Available Objectives. Investigate the effects of selected factors associated with quantitative ultrasound parameters among Inuit preschoolers living in Arctic communities (56° 32′–72° 40′N. Materials and methods. Children were selected randomly in summer and early fall (n=296. Dietary intake was assessed through the administration of a 24-h dietary recall (24-h recall and a food frequency questionnaire (FFQ. Anthropometry was measured using standardized procedures. Plasma 25-hydroxy vitamin D (25(OHD and parathyroid hormone (PTH were measured using a chemiluminescent assay (Liaison, Diasorin. Quantitative ultrasound parameters were measured using Sahara Sonometer, (Hologic Inc.. Results. Children divided by speed of sound (SoS and broadband ultrasound attenuation (BUA quartiles were not different for age (years, sex (M/F, calcium (mg/d and vitamin D intake (µg/d and plasma 25(OHD concentration (nmol/L. However, children in the highest BUA and SoS quartile had higher body mass index (BMI compared to those in quartile 1. Using multivariate linear regression, higher BMI, older age and monounsaturated fatty acids (MUFA intake were predictors of BUA while only BMI was a predictor of SoS. Conclusions. Further investigation assessing intakes of traditional foods (TF and nutrients affecting bone parameters along with assessment of vitamin D status of Inuit children across seasons is required.

  14. Quantitative Determination of Tenuazonic Acid in Pig and Broiler Chicken Plasma by LC-MS/MS and Its Comparative Toxicokinetics.

    Science.gov (United States)

    Fraeyman, Sophie; Devreese, Mathias; Broekaert, Nathan; De Mil, Thomas; Antonissen, Gunther; De Baere, Siegrid; De Backer, Patrick; Rychlik, Michael; Croubels, Siska

    2015-09-30

    A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantitate tenuazonic acid (TeA) in pig and broiler chicken plasma was successfully developed and validated. Linear matrix-matched calibration curves ranged between 5 and 200 ng/mL. Correlation coefficients, goodness-of-fit coefficients, and within-day and between-day precision and accuracy fell well within the acceptance criteria. The limit of quantitation was 5.0 ng/mL in both pig and broiler chicken plasma. The LC-MS/MS method was applied in a comparative toxicokinetic study in both pigs and broiler chickens. TeA was completely bioavailable after oral administration in both animal species. However, absorption was deemed to be slower in broiler chickens (mean tmax 0.32 h in pigs vs 2.60 h in chickens). TeA was more slowly eliminated in broiler chickens (mean t1/2el 0.55 h in pigs vs 2.45 h in chickens after oral administration), mainly due to the significantly lower total body clearance (mean Cl 446.1 mL/h/kg in pigs vs 59.2 mL/h/kg in chickens after oral administration). Tissue residue studies and further research to elucidate the biotransformation and excretion processes of TeA in pigs, broiler chickens, and other animal species are imperative.

  15. Higher body mass, older age and higher monounsaturated fatty acids intake reflect better quantitative ultrasound parameters in Inuit preschoolers

    Science.gov (United States)

    Hayek, Jessy El; Egeland, Grace; Weiler, Hope

    2012-01-01

    Objectives Investigate the effects of selected factors associated with quantitative ultrasound parameters among Inuit preschoolers living in Arctic communities (56° 32′–72° 40′N). Materials and methods Children were selected randomly in summer and early fall (n=296). Dietary intake was assessed through the administration of a 24-h dietary recall (24-h recall) and a food frequency questionnaire (FFQ). Anthropometry was measured using standardized procedures. Plasma 25-hydroxy vitamin D (25(OH)D) and parathyroid hormone (PTH) were measured using a chemiluminescent assay (Liaison, Diasorin). Quantitative ultrasound parameters were measured using Sahara Sonometer, (Hologic Inc.). Results Children divided by speed of sound (SoS) and broadband ultrasound attenuation (BUA) quartiles were not different for age (years), sex (M/F), calcium (mg/d) and vitamin D intake (µg/d) and plasma 25(OH)D concentration (nmol/L). However, children in the highest BUA and SoS quartile had higher body mass index (BMI) compared to those in quartile 1. Using multivariate linear regression, higher BMI, older age and monounsaturated fatty acids (MUFA) intake were predictors of BUA while only BMI was a predictor of SoS. Conclusions Further investigation assessing intakes of traditional foods (TF) and nutrients affecting bone parameters along with assessment of vitamin D status of Inuit children across seasons is required. PMID:22789515

  16. Quantification of Lewis acid induced Brønsted acidity of protogenic Lewis bases.

    Science.gov (United States)

    Lathem, A Paige; Heiden, Zachariah M

    2017-05-09

    Proton transfer promoted by the coordination of protogenic Lewis bases to a Lewis acid is a critical step in catalytic transformations. Although the acidification of water upon coordination to a Lewis acid has been known for decades, no attempts have been made to correlate the Brønsted acidity of the coordinated water molecule with Lewis acid strength. To probe this effect, the pKa's (estimated error of 1.3 pKa units) in acetonitrile of ten protogenic Lewis bases coordinated to seven Lewis acids containing Lewis acidities varying 70 kcal mol(-1), were computed. To quantify Lewis acid strength, the ability to transfer a hydride (hydride donor ability) from the respective main group hydride was used. Coordination of a Lewis acid to water increased the acidity of the bound water molecule between 20 and 50 pKa units. A linear correlation exhibiting a 2.6 pKa unit change of the Lewis acid-water adduct per ten kcal mol(-1) change in hydride donor ability of the respective main group hydride was obtained. For the ten protogenic Lewis bases studied, the coordinated protogenic Lewis bases were acidified between 10 and 50 pKa units. On average, a ten kcal mol(-1) change in hydride donor ability of the respective main group hydride resulted in about a 2.8 pKa unit change in the Brønsted acidity of the Lewis acid-Lewis base adducts. Since attempts to computationally investigate the pKa of main group dihydrogen complexes were unsuccessful, experimental determination of the first reported pKa of a main group dihydrogen complex is described. The pKa of H2-B(C6F5)3 was determined to be 5.8 ± 0.2 in acetonitrile.

  17. Quantitative nucleic acid amplification methods and their implications in clinical virology

    Science.gov (United States)

    Singh, Mini P; Galhotra, Shipra; Saigal, Karnika; Kumar, Archit; Ratho, Radha Kanta

    2017-01-01

    Recently, a number of techniques have been approved for quantification of viral nucleic acids in clinical samples. Viral load (VL) tests have considerable importance in the management of patients and are widely used in routine diagnosis. In clinical virology, VL testing are important to monitor the antiviral treatment, to initiate preemptive therapy, to understand pathogenesis, and to evaluate the infectivity. These tests have now become a part of many diagnostic and treatment guidelines. Considering the various challenges for in-house viral testing related to the standardization, validation, and precision; they are gradually being replaced by the United States Food and Drug Administration (US FDA) cleared tests. This review summarizes the various viral quantification methods and also discusses the clinical applicability of these in human immunodeficiency virus, Hepatitis B virus, Hepatitis C virus, Cytomegalovirus, and Epstein Barr virus infected patients. Further the challenges and future perspectives of VL testing have also been discussed.

  18. Quantitative structure activity relationships of some pyridine derivatives as corrosion inhibitors of steel in acidic medium.

    Science.gov (United States)

    El Ashry, El Sayed H; El Nemr, Ahmed; Ragab, Safaa

    2012-03-01

    Quantum chemical calculations using the density functional theory (B3LYP/6-31G DFT) and semi-empirical AM1 methods were performed on ten pyridine derivatives used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between molecular structure and their inhibition efficiencies. Quantum chemical parameters such as total negative charge (TNC) on the molecule, energy of highest occupied molecular orbital (E (HOMO)), energy of lowest unoccupied molecular orbital (E (LUMO)) and dipole moment (μ) as well as linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π) were correlated to corrosion inhibition efficiency of ten pyridine derivatives. A possible correlation between corrosion inhibition efficiencies and structural properties was searched to reduce the number of compounds to be selected for testing from a library of compounds. It was found that theoretical data support the experimental results. The results were used to predict the corrosion inhibition of 24 related pyridine derivatives.

  19. Quantitative kidney scintigraphy in children, using technetium-labelled dimercaptosuccinic acid

    Energy Technology Data Exchange (ETDEWEB)

    Bouissou, F.; Danet, B.; Meguira, B. and others

    1988-04-30

    Separate measurement of renal function is essential in children with urinary tract disease. This can be done satisfactorily by means of kidney scintigraphy with technetium 99m-labelled dimercaptosuccinic acid. A retrospective study of the records of 415 children, which comprised renal function tests, radiology and scintigraphy, confirmed the value of the radioisotope technique. Graphs of height, kidney uptake and kidney uptake density in relation to age were established, showing highly significant correlations with renal function tests and intravenous urography results, but many dissociations were encountered. Separate renal function evaluation by radioisotope scintigraphy seems to be more reliable than evaluation extrapolated from measurement of the cortical areas at intravenous urography. In vesico-ureteral reflux scintigraphy makes it possible to detect reflux nephropathy at an earlier stage than with other methods.

  20. Quantitative nucleic acid amplification methods and their implications in clinical virology.

    Science.gov (United States)

    Singh, Mini P; Galhotra, Shipra; Saigal, Karnika; Kumar, Archit; Ratho, Radha Kanta

    2017-01-01

    Recently, a number of techniques have been approved for quantification of viral nucleic acids in clinical samples. Viral load (VL) tests have considerable importance in the management of patients and are widely used in routine diagnosis. In clinical virology, VL testing are important to monitor the antiviral treatment, to initiate preemptive therapy, to understand pathogenesis, and to evaluate the infectivity. These tests have now become a part of many diagnostic and treatment guidelines. Considering the various challenges for in-house viral testing related to the standardization, validation, and precision; they are gradually being replaced by the United States Food and Drug Administration (US FDA) cleared tests. This review summarizes the various viral quantification methods and also discusses the clinical applicability of these in human immunodeficiency virus, Hepatitis B virus, Hepatitis C virus, Cytomegalovirus, and Epstein Barr virus infected patients. Further the challenges and future perspectives of VL testing have also been discussed.

  1. Quantitative Assessment of a Field-Based Course on Integrative Geology, Ecology and Cultural History

    Science.gov (United States)

    Sheppard, Paul R.; Donaldson, Brad A.; Huckleberry, Gary

    2010-01-01

    A field-based course at the University of Arizona called Sense of Place (SOP) covers the geology, ecology and cultural history of the Tucson area. SOP was quantitatively assessed for pedagogical effectiveness. Students of the Spring 2008 course were given pre- and post-course word association surveys in order to assess awareness and comprehension…

  2. Experiencing Teaching and Learning Quantitative Reasoning in a Project-Based Context

    Science.gov (United States)

    Muir, Tracey; Beswick, Kim; Callingham, Rosemary; Jade, Katara

    2016-01-01

    This paper presents the findings of a small-scale study that investigated the issues and challenges of teaching and learning about quantitative reasoning (QR) within a project-based learning (PjBL) context. Students and teachers were surveyed and interviewed about their experiences of learning and teaching QR in that context in contrast to…

  3. A Quantitative Comparative Study Measuring Consumer Satisfaction Based on Health Record Format

    Science.gov (United States)

    Moore, Vivianne E.

    2013-01-01

    This research study used a quantitative comparative method to investigate the relationship between consumer satisfaction and communication based on the format of health record. The central problem investigated in this research study related to the format of health record used and consumer satisfaction with care provided and effect on communication…

  4. Poem Generator: A Comparative Quantitative Evaluation of a Microworlds-Based Learning Approach for Teaching English

    Science.gov (United States)

    Jenkins, Craig

    2015-01-01

    This paper is a comparative quantitative evaluation of an approach to teaching poetry in the subject domain of English that employs a "guided discovery" pedagogy using computer-based microworlds. It uses a quasi-experimental design in order to measure performance gains in computational thinking and poetic thinking following a…

  5. Quantitative Assessment of a Field-Based Course on Integrative Geology, Ecology and Cultural History

    Science.gov (United States)

    Sheppard, Paul R.; Donaldson, Brad A.; Huckleberry, Gary

    2010-01-01

    A field-based course at the University of Arizona called Sense of Place (SOP) covers the geology, ecology and cultural history of the Tucson area. SOP was quantitatively assessed for pedagogical effectiveness. Students of the Spring 2008 course were given pre- and post-course word association surveys in order to assess awareness and comprehension…

  6. QUANTITATIVE EVALUATION METHOD OF ELEMENTS PRIORITY OF CARTOGRAPHIC GENERALIZATION BASED ON TAXI TRAJECTORY DATA

    Directory of Open Access Journals (Sweden)

    Z. Long

    2017-09-01

    Full Text Available Considering the lack of quantitative criteria for the selection of elements in cartographic generalization, this study divided the hotspot areas of passengers into parts at three levels, gave them different weights, and then classified the elements from the different hotspots. On this basis, a method was proposed to quantify the priority of elements selection. Subsequently, the quantitative priority of different cartographic elements was summarized based on this method. In cartographic generalization, the method can be preferred to select the significant elements and discard those that are relatively non-significant.

  7. General base-general acid catalysis by terpenoid cyclases.

    Science.gov (United States)

    Pemberton, Travis A; Christianson, David W

    2016-07-01

    Terpenoid cyclases catalyze the most complex reactions in biology, in that more than half of the substrate carbon atoms often undergo changes in bonding during the course of a multistep cyclization cascade that proceeds through multiple carbocation intermediates. Many cyclization mechanisms require stereospecific deprotonation and reprotonation steps, and most cyclization cascades are terminated by deprotonation to yield an olefin product. The first bacterial terpenoid cyclase to yield a crystal structure was pentalenene synthase from Streptomyces exfoliatus UC5319. This cyclase generates the hydrocarbon precursor of the pentalenolactone family of antibiotics. The structures of pentalenene synthase and other terpenoid cyclases reveal predominantly nonpolar active sites typically lacking amino acid side chains capable of serving general base-general acid functions. What chemical species, then, enables the Brønsted acid-base chemistry required in the catalytic mechanisms of these enzymes? The most likely candidate for such general base-general acid chemistry is the co-product inorganic pyrophosphate. Here, we briefly review biological and nonbiological systems in which phosphate and its derivatives serve general base and general acid functions in catalysis. These examples highlight the fact that the Brønsted acid-base activities of phosphate derivatives are comparable to the Brønsted acid-base activities of amino acid side chains.

  8. 基于氨基酸性质的EB病毒抗原MHC-I类分子限制性表位的定量构效关系建模%Quantitative structure-activity relationship modeling of MHC class-Ⅰrestrained antigenic epitope of Epstein-Barr virus based on the properties of amino acids

    Institute of Scientific and Technical Information of China (English)

    韩英子; 王远强; 胡勇; 纪永军; 路亚阔; 蓝君; 罗鸿; 林治华

    2013-01-01

    目的 建立EB病毒(EBBV)抗原表位的理论计算模型并用于其定量预测,为肿瘤免疫的多肽疫苗设计提供理论基础.方法 从表位数据库中收集33条EBV抗原表位,使用逐步回归(STR)方法筛选2个对平衡解离常数(KD)贡献较大的结构参数用于表位的结构表征,最后用多元线性回归(MLR)方法建立结构参数与KD的定量构效关系(QSAR)模型.结果 该模型具有较好的稳定性(R2=0.637,Q2=0.581)与预测能力(R2test=0.501).结论 此方法可确定表位中各个氨基酸的物理性质对于平衡解离常数的贡献,为表位设计与改造提供直接线索;STR和MLR相结合建模方法具有物化意义明确、易于解释及操作简便易行等优点.%Epstein-Barr virus (EBV) is highly associated with several neoplastic diseases. The development of vaccine based on the antigenic epitope is very important for immunotherapies of human cancers. It is necessary to construct theoretical model for quantitative prediction of epitope, because the identification and screen of epitope need long time and high cost through experiments. In this study, 33 epitopes from EBV had been collected from epitope database. Then, the properties with significant contribution for equilibrium dissociation constant (KD) were screened by the stepwise, which were used to characterize the epitopes. Finally, the quantitative structure-activity relationship model between structural variables and KD was constructed by multiple linear regressions (MLR). The QSAR model has good reliability (R2=0.637, Q2=0.581) and predictive ability (R2test=0.501), and can provide more clues for the design and modification of epitope. The QSAR model constructed by STR and MLR has some advantages, such as good reliability and predictive ability, definitive physiochemical meaning and easier operation, and it can guide the rational design and structural modification of epitope directly.

  9. A gold nanoparticle-based semi-quantitative and quantitative ultrasensitive paper sensor for the detection of twenty mycotoxins

    Science.gov (United States)

    Kong, Dezhao; Liu, Liqiang; Song, Shanshan; Suryoprabowo, Steven; Li, Aike; Kuang, Hua; Wang, Libing; Xu, Chuanlai

    2016-02-01

    A semi-quantitative and quantitative multi-immunochromatographic (ICA) strip detection assay was developed for the simultaneous detection of twenty types of mycotoxins from five classes, including zearalenones (ZEAs), deoxynivalenols (DONs), T-2 toxins (T-2s), aflatoxins (AFs), and fumonisins (FBs), in cereal food samples. Sensitive and specific monoclonal antibodies were selected for this assay. The semi-quantitative results were obtained within 20 min by the naked eye, with visual limits of detection for ZEAs, DONs, T-2s, AFs and FBs of 0.1-0.5, 2.5-250, 0.5-1, 0.25-1 and 2.5-10 μg kg-1, and cut-off values of 0.25-1, 5-500, 1-10, 0.5-2.5 and 5-25 μg kg-1, respectively. The quantitative results were obtained using a hand-held strip scan reader, with the calculated limits of detection for ZEAs, DONs, T-2s, AFs and FBs of 0.04-0.17, 0.06-49, 0.15-0.22, 0.056-0.49 and 0.53-1.05 μg kg-1, respectively. The analytical results of spiked samples were in accordance with the accurate content in the simultaneous detection analysis. This newly developed ICA strip assay is suitable for the on-site detection and rapid initial screening of mycotoxins in cereal samples, facilitating both semi-quantitative and quantitative determination.A semi-quantitative and quantitative multi-immunochromatographic (ICA) strip detection assay was developed for the simultaneous detection of twenty types of mycotoxins from five classes, including zearalenones (ZEAs), deoxynivalenols (DONs), T-2 toxins (T-2s), aflatoxins (AFs), and fumonisins (FBs), in cereal food samples. Sensitive and specific monoclonal antibodies were selected for this assay. The semi-quantitative results were obtained within 20 min by the naked eye, with visual limits of detection for ZEAs, DONs, T-2s, AFs and FBs of 0.1-0.5, 2.5-250, 0.5-1, 0.25-1 and 2.5-10 μg kg-1, and cut-off values of 0.25-1, 5-500, 1-10, 0.5-2.5 and 5-25 μg kg-1, respectively. The quantitative results were obtained using a hand-held strip scan

  10. Quantitative study on crack of meso-damage and fracture concrete based on CT technique

    Indian Academy of Sciences (India)

    Wei Tian; Faning Dang; Yongli Xie

    2015-02-01

    The meso-mechanics experiment of concrete specimen is carried out by means of CT technology, the whole degradation deformation process of meso-cracks generation, propagation, coalescence and failure is obtained under uniaxial compression condition. Based on CT image of concrete meso-damage evolution, the recognition and extraction of meso-cracks are realized by means of the digital imageprocessing (DIP) technique, and the basic geometrical characteristics of meso-crack patterns are statistically analysed from length, width and area. The quantitative analysis of the meso-fracture process of concrete materials is performed. The results demonstrate that the quantitative analysis of the internal meso-crack of concrete can be taken as a quantitative index to reflect the damage and fracture process thereby the meso-fracture mechanism of concrete material is thoroughly investigated. So it has brought forth some new ideas to the study of damage evolution law of concrete under uniaxial compression condition.

  11. Quantitative analysis of mycosporine-like amino acids in marine algae by capillary electrophoresis with diode-array detection

    Science.gov (United States)

    Hartmann, Anja; Murauer, Adele; Ganzera, Markus

    2017-01-01

    Marine species have evolved a variety of physical or chemical strategies to diminish damage from elevated environmental ultraviolet radiation. Mycosporine-like amino acids, a group of widely distributed small water soluble compounds, are biologically relevant because of their photo-protective potential. In addition, presumed antioxidant and skin protective strategies raise the interest for possible medicinal and cosmetic applications. In this study the first CE method for the quantification of mycosporine-like amino acids in marine species is presented. A borate buffer system consisting of 30 mM sodium tetraborate in water at a pH-value of 10.3 enabled the baseline separation of five MAAs, namely palythine, mycosporine-serinol, asterina-330, shinorine and porphyra-334, in 27 min. Separation voltage, temperature and detection wavelength were 25 kV, 25 °C and 320 nm, respectively. The optimized method was fully validated and applied for the quantitative determination of MAAs in the marine macroalgae Palmaria palmata, Porphyra umbilicalis, and Porphyra sp., as well as the lichen Lichina pygmaea. PMID:28213175

  12. Quantitative analysis of mycosporine-like amino acids in marine algae by capillary electrophoresis with diode-array detection.

    Science.gov (United States)

    Hartmann, Anja; Murauer, Adele; Ganzera, Markus

    2017-05-10

    Marine species have evolved a variety of physical or chemical strategies to diminish damage from elevated environmental ultraviolet radiation. Mycosporine-like amino acids, a group of widely distributed small water soluble compounds, are biologically relevant because of their photo-protective potential. In addition, presumed antioxidant and skin protective strategies raise the interest for possible medicinal and cosmetic applications. In this study the first CE method for the quantification of mycosporine-like amino acids in marine species is presented. A borate buffer system consisting of 30mM sodium tetraborate in water at a pH-value of 10.3 enabled the baseline separation of five MAAs, namely palythine, mycosporine-serinol, asterina-330, shinorine and porphyra-334, in 27min. Separation voltage, temperature and detection wavelength were 25kV, 25°C and 320nm, respectively. The optimized method was fully validated and applied for the quantitative determination of MAAs in the marine macroalgae Palmaria palmata, Porphyra umbilicalis, and Porphyra sp., as well as the lichen Lichina pygmaea.

  13. Quantitative evaluation of noncovalent interactions between polyphosphate and dissolved humic acids in aqueous conditions.

    Science.gov (United States)

    Fang, Wei; Sheng, Guo-Ping; Wang, Long-Fei; Ye, Xiao-Dong; Yu, Han-Qing

    2015-12-01

    As one kind of phosphorus species, polyphosphate (poly-P) is ubiquitous in natural environments, and the potential interactions between poly-P and humic substances in the sediments or natural waters would influence the fate of poly-P in the environments. However, the mechanism of the interactions has not yet been understood clearly. In this work, the characteristics and mechanisms of the interactions between humic acids (HA) and two model poly-P compounds with various chain lengths have been investigated. Results show that a stable polyphosphate-HA complex would be formed through the noncovalent interactions, and hydrogen bond might be the main driving force for the binding process, which might be formed between the proton-accepting groups of poly-P (e.g., PO and P-O(-)) and the oxygen containing functional groups in HA. Our findings implied that the presence of humic substances in natural waters, soils and sediments would influence the potential transport and/or mobility of environmental poly-P.

  14. Carbon-based strong solid acid for cornstarch hydrolysis

    Science.gov (United States)

    Nata, Iryanti Fatyasari; Irawan, Chairul; Mardina, Primata; Lee, Cheng-Kang

    2015-10-01

    Highly sulfonated carbonaceous spheres with diameter of 100-500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO3H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO3H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst.

  15. Probe-based Real-time PCR Approaches for Quantitative Measurement of microRNAs

    Science.gov (United States)

    Wong, Wilson; Farr, Ryan; Joglekar, Mugdha; Januszewski, Andrzej; Hardikar, Anandwardhan

    2015-01-01

    Probe-based quantitative PCR (qPCR) is a favoured method for measuring transcript abundance, since it is one of the most sensitive detection methods that provides an accurate and reproducible analysis. Probe-based chemistry offers the least background fluorescence as compared to other (dye-based) chemistries. Presently, there are several platforms available that use probe-based chemistry to quantitate transcript abundance. qPCR in a 96 well plate is the most routinely used method, however only a maximum of 96 samples or miRNAs can be tested in a single run. This is time-consuming and tedious if a large number of samples/miRNAs are to be analyzed. High-throughput probe-based platforms such as microfluidics (e.g. TaqMan Array Card) and nanofluidics arrays (e.g. OpenArray) offer ease to reproducibly and efficiently detect the abundance of multiple microRNAs in a large number of samples in a short time. Here, we demonstrate the experimental setup and protocol for miRNA quantitation from serum or plasma-EDTA samples, using probe-based chemistry and three different platforms (96 well plate, microfluidics and nanofluidics arrays) offering increasing levels of throughput. PMID:25938938

  16. Reactive Distillation for Esterification of Bio-based Organic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Fields, Nathan; Miller, Dennis J.; Asthana, Navinchandra S.; Kolah, Aspi K.; Vu, Dung; Lira, Carl T.

    2008-09-23

    The following is the final report of the three year research program to convert organic acids to their ethyl esters using reactive distillation. This report details the complete technical activities of research completed at Michigan State University for the period of October 1, 2003 to September 30, 2006, covering both reactive distillation research and development and the underlying thermodynamic and kinetic data required for successful and rigorous design of reactive distillation esterification processes. Specifically, this project has led to the development of economical, technically viable processes for ethyl lactate, triethyl citrate and diethyl succinate production, and on a larger scale has added to the overall body of knowledge on applying fermentation based organic acids as platform chemicals in the emerging biorefinery. Organic acid esters constitute an attractive class of biorenewable chemicals that are made from corn or other renewable biomass carbohydrate feedstocks and replace analogous petroleum-based compounds, thus lessening U.S. dependence on foreign petroleum and enhancing overall biorefinery viability through production of value-added chemicals in parallel with biofuels production. Further, many of these ester products are candidates for fuel (particularly biodiesel) components, and thus will serve dual roles as both industrial chemicals and fuel enhancers in the emerging bioeconomy. The technical report from MSU is organized around the ethyl esters of four important biorenewables-based acids: lactic acid, citric acid, succinic acid, and propionic acid. Literature background on esterification and reactive distillation has been provided in Section One. Work on lactic acid is covered in Sections Two through Five, citric acid esterification in Sections Six and Seven, succinic acid in Section Eight, and propionic acid in Section Nine. Section Ten covers modeling of ester and organic acid vapor pressure properties using the SPEAD (Step Potential

  17. 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...

  18. Facile syntheses of dissymmetric ferrocene-functionalized Lewis acids and acid-base pairs.

    Science.gov (United States)

    Morgan, Ian R; Di Paolo, Angela; Vidovic, Dragoslav; Fallis, Ian A; Aldridge, Simon

    2009-12-21

    A facile synthetic approach is reported for the synthesis of dissymmetric 1,2-ferrocenediyl Lewis acids and mixed acid-base pairs including the first example of a 1-phosphino-2-borylferrocene; the use of non-racemic electrophiles allows for the isolation of single diastereomer products.

  19. The quantitative Morse theorem

    OpenAIRE

    Loi, Ta Le; Phien, Phan

    2013-01-01

    In this paper, we give a proof of the quantitative Morse theorem stated by {Y. Yomdin} in \\cite{Y1}. The proof is based on the quantitative Sard theorem, the quantitative inverse function theorem and the quantitative Morse lemma.

  20. Quantitative Analysis of the Distribution of cis-Eicosenoic Acid Positional Isomers in Marine Fishes from the Indian Ocean.

    Science.gov (United States)

    Senarath, Samanthika; Yoshinaga, Kazuaki; Nagai, Toshiharu; Yoshida, Akihiko; Beppu, Fumiaki; Jayasinghe, Chamila; Devadawson, Chandravathany; Gotoh, Naohiro

    2017-02-01

    This study investigated the occurrence and distribution of cis-eicosenoic acid (c-20:1) positional isomers in fishes from the Indian Ocean and compared to those from the Pacific and Atlantic Ocean. Lipids were extracted from the edible part of the fish and then methylated. The eicosenoic acid methyl ester fraction was separated from total fatty acid methyl esters by reversed-phase HPLC and quantitatively analyzed using a GC-FID fitted with the SLB-IL111 highly polar GC column. c14-20:1 was used as an internal standard. The results indicated that the highest levels of c-20:1 positional isomers were found in fishes from the Pacific Ocean (saury, 166.95±12.4 mg/g of oil), followed by the Atlantic Ocean (capelin, 162.7±3.5 mg/g of oil), and lastly in fishes from the Indian Ocean (goatfish, 34.39 mg/g of oil). With only a few exceptions, the most abundant 20:1 positional isomer found in fishes of the Indian and Atlantic Ocean was the c11-20:1 isomer (>50%) followed by the c13-20:1 isomer (<25%). Unusually, the c7-20:1 isomer was predominantly found in a few fishes such as the tooth ponyfish, longface emperor, and commerson's sole. The c9, c5, and c15-20:1 isomers were the least occurring in fishes from the Indian and Atlantic Ocean. In contrast, the c9-20:1 isomer was the principal isomer identified in fishes from the Pacific Ocean. The results revealed that the content and distribution of c-20:1 positional isomers varied among fishes in different oceans. The data presented in the current study are the first to report on the distribution of c-20:1 positional isomers in fishes from the Indian Ocean.

  1. Quantitative use of fluorescent in situ hybridization to examine relationships between mycolic acid-containing actinomycetes and foaming in activated sludge plants.

    Science.gov (United States)

    Davenport, R J; Curtis, T P; Goodfellow, M; Stainsby, F M; Bingley, M

    2000-03-01

    The formation of viscous foams on aeration basins and secondary clarifiers of activated sludge plants is a common and widespread problem. Foam formation is often attributed to the presence of mycolic acid-containing actinomycetes (mycolata). In order to examine the relationship between the number of mycolata and foam, we developed a group-specific probe targeting the 16S rRNA of the mycolata, a protocol to permeabilize mycolata, and a statistically robust quantification method. Statistical analyses showed that a lipase-based permeabilization method was quantitatively superior to previously described methods (P < 0.05). When mixed liquor and foam samples were examined, most of the mycolata present were rods or cocci, although filamentous mycolata were also observed. A nested analysis of variance showed that virtually all of the measured variance occurred between fields of view and not between samples. On this basis we determined that as few as five fields of view could be used to give a statistically meaningful sample. Quantitative fluorescent in situ hybridization (FISH) was used to examine the relationship between foaming and the concentration of mycolata in a 20-m(3) completely mixed activated sludge plant. Foaming occurred when the number of mycolata exceeded a certain threshold value. Baffling of the plant affected foaming without affecting the number of mycolata. We tentatively estimated that the threshold foaming concentration of mycolata was about 2 x 10(6) cells ml(-1) or 4 x 10(12) cells m(-2). We concluded that quantitative use of FISH is feasible and that quantification is a prerequisite for rational investigation of foaming in activated sludge.

  2. Polymerization of amino acids containing nucleotide bases

    Science.gov (United States)

    Ben Cheikh, Azzouz; Orgel, Leslie E.

    1990-01-01

    The nucleoamino acids 1-(3'-amino,3'-carboxypropyl)uracil (3) and 9-(3'-amino,3'-carboxypropyl)adenine (4) have been prepared as (L)-en-antiomers and as racemic mixtures. When 3 or 4 is suspended in water and treated with N,N'-carbon-yldiimidazole, peptides are formed in good yield. The products formed from the (L)-enantiomers are hydrolyzed to the monomeric amino acids by pronase. Attempts to improve the efficiency of these oligomerizations by including a polyuridylate template in the reaction mixture were not successful. Similarly, oligomers derived from the (L)-enantiomer of 3 did not act as templates to facilitate the oligomerization of 4.

  3. Carbon-based strong solid acid for cornstarch hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Nata, Iryanti Fatyasari, E-mail: yanti_tkunlam@yahoo.com [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Irawan, Chairul; Mardina, Primata [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Lee, Cheng-Kang, E-mail: cklee@mail.ntust.edu.tw [Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Rd. Sec.4, Taipei 106, Taiwan (China)

    2015-10-15

    Highly sulfonated carbonaceous spheres with diameter of 100–500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO{sub 3}H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO{sub 3}H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst. - Highlights: • Carbon solid acid was successfully prepared by one-step hydrothermal carbonization. • The acrylic acid as monomer was effectively reduce the diameter size of particle. • The solid acid catalyst show good catalytic performance of starch hydrolysis. • The solid acid catalyst is not significantly deteriorated after repeated use.

  4. Multi-objective intelligent coordinating optimization blending system based on qualitative and quantitative synthetic model

    Institute of Scientific and Technical Information of China (English)

    WANG Ya-lin; MA Jie; GUI Wei-hua; YANG Chun-hua; ZHANG Chuan-fu

    2006-01-01

    A multi-objective intelligent coordinating optimization strategy based on qualitative and quantitative synthetic model for Pb-Zn sintering blending process was proposed to obtain optimal mixture ratio. The mechanism and neural network quantitative models for predicting compositions and rule models for expert reasoning were constructed based on statistical data and empirical knowledge. An expert reasoning method based on these models were proposed to solve blending optimization problem, including multi-objective optimization for the first blending process and area optimization for the second blending process, and to determine optimal mixture ratio which will meet the requirement of intelligent coordination. The results show that the qualified rates of agglomerate Pb, Zn and S compositions are increased by 7.1%, 6.5% and 6.9%, respectively, and the fluctuation of sintering permeability is reduced by 7.0 %, which effectively stabilizes the agglomerate compositions and the permeability.

  5. Nucleic Acid--Based Nanodevices in Biological Imaging

    Science.gov (United States)

    Chakraborty, Kasturi; Veetil, Aneesh T.

    2017-01-01

    The nanoscale engineering of nucleic acids has led to exciting molecular technologies for high-end biological imaging. The predictable base pairing, high programmability, and superior new chemical and biological methods used to access nucleic acids with diverse lengths and in high purity, coupled with computational tools for their design, have allowed the creation of a stunning diversity of nucleic acid--based nanodevices. Given their biological origin, such synthetic devices have a tremendous capacity to interface with the biological world, and this capacity lies at the heart of several nucleic acid--based technologies that are finding applications in biological systems. We discuss these diverse applications and emphasize the advantage, in terms of physicochemical properties, that the nucleic acid scaffold brings to these contexts. As our ability to engineer this versatile scaffold increases, its applications in structural, cellular, and organismal biology are clearly poised to massively expand. PMID:27294440

  6. Nucleic Acid-Based Nanodevices in Biological Imaging.

    Science.gov (United States)

    Chakraborty, Kasturi; Veetil, Aneesh T; Jaffrey, Samie R; Krishnan, Yamuna

    2016-06-02

    The nanoscale engineering of nucleic acids has led to exciting molecular technologies for high-end biological imaging. The predictable base pairing, high programmability, and superior new chemical and biological methods used to access nucleic acids with diverse lengths and in high purity, coupled with computational tools for their design, have allowed the creation of a stunning diversity of nucleic acid-based nanodevices. Given their biological origin, such synthetic devices have a tremendous capacity to interface with the biological world, and this capacity lies at the heart of several nucleic acid-based technologies that are finding applications in biological systems. We discuss these diverse applications and emphasize the advantage, in terms of physicochemical properties, that the nucleic acid scaffold brings to these contexts. As our ability to engineer this versatile scaffold increases, its applications in structural, cellular, and organismal biology are clearly poised to massively expand.

  7. 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...

  8. Respiratory Acid-Base Disorders in the Critical Care Unit.

    Science.gov (United States)

    Hopper, Kate

    2017-03-01

    The incidence of respiratory acid-base abnormalities in the critical care unit (CCU) is unknown, although respiratory alkalosis is suspected to be common in this population. Abnormal carbon dioxide tension can have many physiologic effects, and changes in Pco2 may have a significant impact on outcome. Monitoring Pco2 in CCU patients is an important aspect of critical patient assessment, and identification of respiratory acid-base abnormalities can be valuable as a diagnostic tool. Treatment of respiratory acid-base disorders is largely focused on resolution of the primary disease, although mechanical ventilation may be indicated in cases with severe respiratory acidosis. Published by Elsevier Inc.

  9. A Novel Quantitative Analysis Model for Information System Survivability Based on Conflict Analysis

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; WANG Huiqiang; ZHAO Guosheng

    2007-01-01

    This paper describes a novel quantitative analysis model for system survivability based on conflict analysis, which provides a direct-viewing survivable situation. Based on the three-dimensional state space of conflict, each player's efficiency matrix on its credible motion set can be obtained. The player whose desire is the strongest in all initiates the moving and the overall state transition matrix of information system may be achieved. In addition, the process of modeling and stability analysis of conflict can be converted into a Markov analysis process, thus the obtained results with occurring probability of each feasible situation will help the players to quantitatively judge the probability of their pursuing situations in conflict. Compared with the existing methods which are limited to post-explanation of system's survivable situation, the proposed model is relatively suitable for quantitatively analyzing and forecasting the future development situation of system survivability. The experimental results show that the model may be effectively applied to quantitative analysis for survivability. Moreover, there will be a good application prospect in practice.

  10. Environmentally Benign Bifunctional Solid Acid and Base Catalysts

    NARCIS (Netherlands)

    Elmekawy, A.; Shiju, N.R.; Rothenberg, G.; Brown, D.R.

    2014-01-01

    Solid bifunctional acid-​base catalysts were prepd. in two ways on an amorphous silica support: (1) by grafting mercaptopropyl units (followed by oxidn. to propylsulfonic acid) and aminopropyl groups to the silica surface (NH2-​SiO2-​SO3H)​, and (2) by grafting only aminopropyl groups and then parti

  11. 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 tra...

  12. Boronic acid-tethered amphiphilic hyaluronic acid derivative-based nanoassemblies for tumor targeting and penetration.

    Science.gov (United States)

    Jeong, Jae Young; Hong, Eun-Hye; Lee, Song Yi; Lee, Jae-Young; Song, Jae-Hyoung; Ko, Seung-Hak; Shim, Jae-Seong; Choe, Sunghwa; Kim, Dae-Duk; Ko, Hyun-Jeong; Cho, Hyun-Jong

    2017-02-16

    (3-Aminomethylphenyl)boronic acid (AMPB)-installed hyaluronic acid-ceramide (HACE)-based nanoparticles (NPs), including manassantin B (MB), were fabricated for tumor-targeted delivery. The amine group of AMPB was conjugated to the carboxylic acid group of hyaluronic acid (HA) via amide bond formation, and synthesis was confirmed by spectroscopic methods. HACE-AMPB/MB NPs with a 239-nm mean diameter, narrow size distribution, negative zeta potential, and >90% drug encapsulation efficiency were fabricated. Exposed AMPB in the outer surface of HACE-AMPB NPs (in the aqueous environment) may react with sialic acid of cancer cells. The improved cellular accumulation efficiency, in vitro antitumor efficacy, and tumor penetration efficiency of HACE-AMPB/MB NPs, compared with HACE/MB NPs, in MDA-MB-231 cells (CD44 receptor-positive human breast adenocarcinoma cells) may be based on the CD44 receptor-mediated endocytosis and phenylboronic acid-sialic acid interaction. Enhanced in vivo tumor targetability, infiltration efficiency, and antitumor efficacies of HACE-AMPB NPs, compared with HACE NPs, were observed in a MDA-MB-231 tumor-xenografted mouse model. In addition to passive tumor targeting (based on an enhanced permeability and retention effect) and active tumor targeting (interaction between HA and CD44 receptor), the phenylboronic acid-sialic acid interaction can play important roles in augmented tumor targeting and penetration of HACE-AMPB NPs. STATEMENT OF SIGNIFICANCE: (3-Aminomethylphenyl)boronic acid (AMPB)-tethered hyaluronic acid-ceramide (HACE)-based nanoparticles (NPs), including manassantin B (MB), were fabricated and their tumor targeting and penetration efficiencies were assessed in MDA-MB-231 (CD44 receptor-positive human adenocarcinoma) tumor models. MB, which exhibited antitumor efficacies via the inhibition of angiogenesis and hypoxia inducible factor (HIF)-1, was entrapped in HACE-AMPB NPs in this study. Phenylboronic acid located in the outer surface

  13. Quantitative structure-activity relationships of antibacterial agents, 7-heterocyclic amine substituted 1-cyclopropyl-6,8-difluoro-4-oxoquinoline-3-carboxylic acids.

    Science.gov (United States)

    Okada, T; Ezumi, K; Yamakawa, M; Sato, H; Tsuji, T; Tsushima, T; Motokawa, K; Komatsu, Y

    1993-01-01

    Quantitative structure-activity relationships (QSAR) of various 7-(3-substituted-azetidin-1-yl)-1-cyclopropyl-6,8-difluoro-1,4-dih ydro-4- oxoquinoline-3-carboxylic acids, 14-25, were studied to clarify the structural requirements for 3-substituted azetidines to potentiate antibacterial activity. A good parabolic relationship seemed to exist between the relative mean antibacterial activity indices against five representative gram-negative bacteria, GNM, and the calculated hydrophobic parameters, CLOG P, of these molecules. The CLOG P value of the most potent derivative was predicted to be around 2.3. On the other hand, against five representative gram-positive bacteria, the relative mean antibacterial activity indices, GPM, remained high and rather constant regardless of structural variation in the azetidine moiety. In order to confirm these findings, the QSAR analysis was extended with success to the quinolonecarboxylic acids, 26-34, which bear various substituted pyrrolidine, piperazine and piperidine derivatives instead of azetidines. The findings showed that the introduction of any amide substituent group to these heterocyclic amine moieties would lead to marked decrease in GNM, whereas incorporation of some amino substituent groups at a position two or three carbons remote from the N-1 position resulted in great enhancement of GNM. As azetidine quinolones exhibited somewhat low in vivo antibacterial activities, possibly reflecting their lesser bioavailability, we finally selected 3-amino-4-methoxypyrrolidine as one of the most promising C-7 substituent groups based on our QSAR analysis.

  14. A locked nucleic Acid-based nanocrawler

    DEFF Research Database (Denmark)

    Astakhova, I Kira; Pasternak, Karol; Campbell, Meghan A

    2013-01-01

    Herein we introduce a novel fluorescent LNA/DNA machine, a nanocrawler, which reversibly moves along a directionally polar complementary road controlled by affinity-enhancing locked nucleic acid (LNA) monomers and additional regulatory strands. Polyaromatic hydrocarbon (PAH) dyes attached to 2......'-amino-LNA monomers are incorporated at four stations of the system, enabling simple detection of the position of the nanocrawler via a step-specific color signal. The sensing is provided by highly sensitive, chemically stable, and photostable PAH LNA interstrand communication systems, including pyrene...

  15. Rapid and simple solid-phase esterification of sialic acid residues for quantitative glycomics by mass spectrometry.

    Science.gov (United States)

    Miura, Yoshiaki; Shinohara, Yasuro; Furukawa, Jun-ichi; Nagahori, Noriko; Nishimura, Shin-Ichiro

    2007-01-01

    A rapid and quantitative method for solid-phase methyl esterification of carboxy groups of various sialylated oligosaccharides has been established. The method employed a triazene derivative, 3-methyl-1-p-tolyltriazene, for facile derivatization of oligosaccharides immobilized onto general solid supports such as Affi-Gel Hz and gold colloidal nanoparticles in a multiwell plate. The workflow protocol was optimized for the solid-phase processing of captured sialylated/unsialylated oligosaccharides separated from crude sample mixtures by chemical ligation. From tryptic and/or PNGase F-digest mixtures of glycoproteins, purification by chemoselective immobilization, esterification and recovery were achieved in the same well of the filter plate within three hours when used in conjunction with "glycoblotting technology" (S.-I. Nishimura, K. Niikura, M. Kurogochi, T. Matsushita, M. Fumoto, H. Hinou, R. Kamitani, H. Nakagawa, K. Deguchi, N. Miura, K. Monde, H. Kondo, High-throughput protein glycomics: Combined use of chemoselective glycoblotting and MALDI-TOF/TOF mass spectrometry: Angew. Chem. 2005, 117, 93-98; Angew. Chem. Int. Ed. 2005, 44, 91-96). The recovered materials were directly applicable to subsequent characterization by mass spectrometric techniques such as MALDI-TOF for large-scale glycomics of both neutral and sialylated oligosaccharides. On-bead/on-gold nanoparticle derivatization of glycans containing sialic acids allowed rapid and quantitative glycoform profiling by MALDI-TOF MS with reflector and positive ion mode. In addition to its simplicity and speed, the method eliminates the use of unfavorable halogenated solvents such as chloroform and dichloromethane or volatile solvents such as diethyl ether and hexane, resulting in a practical and green chemical method for automated robotic adaptation.

  16. Impact of implementation choices on quantitative predictions of cell-based computational models

    Science.gov (United States)

    Kursawe, Jochen; Baker, Ruth E.; Fletcher, Alexander G.

    2017-09-01

    'Cell-based' models provide a powerful computational tool for studying the mechanisms underlying the growth and dynamics of biological tissues in health and disease. An increasing amount of quantitative data with cellular resolution has paved the way for the quantitative parameterisation and validation of such models. However, the numerical implementation of cell-based models remains challenging, and little work has been done to understand to what extent implementation choices may influence model predictions. Here, we consider the numerical implementation of a popular class of cell-based models called vertex models, which are often used to study epithelial tissues. In two-dimensional vertex models, a tissue is approximated as a tessellation of polygons and the vertices of these polygons move due to mechanical forces originating from the cells. Such models have been used extensively to study the mechanical regulation of tissue topology in the literature. Here, we analyse how the model predictions may be affected by numerical parameters, such as the size of the time step, and non-physical model parameters, such as length thresholds for cell rearrangement. We find that vertex positions and summary statistics are sensitive to several of these implementation parameters. For example, the predicted tissue size decreases with decreasing cell cycle durations, and cell rearrangement may be suppressed by large time steps. These findings are counter-intuitive and illustrate that model predictions need to be thoroughly analysed and implementation details carefully considered when applying cell-based computational models in a quantitative setting.

  17. Naked-eye quantitative aptamer-based assay on paper device.

    Science.gov (United States)

    Zhang, Yun; Gao, Dong; Fan, Jinlong; Nie, Jinfang; Le, Shangwang; Zhu, Wenyuan; Yang, Jiani; Li, Jianping

    2016-04-15

    This work initially describes the design of low-cost, naked-eye quantitative aptamer-based assays by using microfluidic paper-based analytical device (μPAD). Two new detection motifs are proposed for quantitative μPAD measurement without using external electronic readers, which depend on the length of colored region in a strip-like μPAD and the number of colorless detection microzones in a multi-zone μPAD. The length measuring method is based on selective color change of paper from colorless to blue-black via formation of iodine-starch complex. The counting method is conducted on the basis of oxidation-reduction reaction between hydrogen peroxide and potassium permanganate. Their utility is well demonstrated with sensitive, specific detection of adenosine as a model analyte with the naked eye in buffer samples and undiluted human serum. These equipment-free quantitative methods proposed thus hold great potential for the development of more aptamer-based assays that are simple, cost-efficient, portable, and user-friendly for various point-of-care applications particularly in resource-constrained environments.

  18. 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.

  19. 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)

  20. Acid-base and potassium disorders in liver disease.

    Science.gov (United States)

    Ahya, Shubhada N; José Soler, Maria; Levitsky, Josh; Batlle, Daniel

    2006-11-01

    Acid-base and potassium disorders occur frequently in the setting of liver disease. As the liver's metabolic function worsens, particularly in the setting of renal dysfunction, hemodynamic compromise, and hepatic encephalopathy, acid-base disorders ensue. The most common acid-base disorder is respiratory alkalosis. Metabolic acidosis alone or in combination with respiratory alkalosis also is common. Acid-base disorders in patients with liver disease are complex. The urine anion gap may help to distinguish between chronic respiratory alkalosis and hyperchloremic metabolic acidosis when a blood gas is not available. A negative urine anion gap helps to rule out chronic respiratory alkalosis. In this disorder a positive urine anion gap is expected owing to suppressed urinary acidification. Distal renal tubular acidosis occurs in autoimmune liver disease such as primary biliary cirrhosis, but often is a functional defect from impaired distal sodium delivery. Potassium disorders are often the result of the therapies used to treat advanced liver disease.

  1. Synthesis and catalytic application of amino acid based dendritic macromolecules

    NARCIS (Netherlands)

    Koten, G. van; Gossage, R.A.; Jastrzebski, J.T.B.H.; Ameijde, J. van; Mulders, S.J.E.; Brouwer, Arwin J.; Liskamp, R.M.J.

    1999-01-01

    The use of amino acid based dendrimers as molecular scaffolds for the attachment of catalytically active organometallic Ni ''pincer'' complexes, via a urea functionality, is described; the dendrimer catalysts have comparable activity to their mononuclear (NCN)NiX analogues.

  2. Acid-base strengths in m-cresol

    NARCIS (Netherlands)

    Bos, M.; Dahmen, E.A.M.F.

    1971-01-01

    For various acids and bases dissociation constants were determined conductimetrically in m-cresol. A glass electrode was calibrated by means of some compounds with dissociation constants known from conductivity measurements. Potentiometric titrations with this calibrated glass electrode gave dissoci

  3. Towards lactic acid bacteria-based biorefineries.

    Science.gov (United States)

    Mazzoli, Roberto; Bosco, Francesca; Mizrahi, Itzhak; Bayer, Edward A; Pessione, Enrica

    2014-11-15

    Lactic acid bacteria (LAB) have long been used in industrial applications mainly as starters for food fermentation or as biocontrol agents or as probiotics. However, LAB possess several characteristics that render them among the most promising candidates for use in future biorefineries in converting plant-derived biomass-either from dedicated crops or from municipal/industrial solid wastes-into biofuels and high value-added products. Lactic acid, their main fermentation product, is an attractive building block extensively used by the chemical industry, owing to the potential for production of polylactides as biodegradable and biocompatible plastic alternative to polymers derived from petrochemicals. LA is but one of many high-value compounds which can be produced by LAB fermentation, which also include biofuels such as ethanol and butanol, biodegradable plastic polymers, exopolysaccharides, antimicrobial agents, health-promoting substances and nutraceuticals. Furthermore, several LAB strains have ascertained probiotic properties, and their biomass can be considered a high-value product. The present contribution aims to provide an extensive overview of the main industrial applications of LAB and future perspectives concerning their utilization in biorefineries. Strategies will be described in detail for developing LAB strains with broader substrate metabolic capacity for fermentation of cheaper biomass.

  4. A Classifier Model based on the Features Quantitative Analysis for Facial Expression Recognition

    Directory of Open Access Journals (Sweden)

    Amir Jamshidnezhad

    2011-01-01

    Full Text Available In recent decades computer technology has considerable developed in use of intelligent systems for classification. The development of HCI systems is highly depended on accurate understanding of emotions. However, facial expressions are difficult to classify by a mathematical models because of natural quality. In this paper, quantitative analysis is used in order to find the most effective features movements between the selected facial feature points. Therefore, the features are extracted not only based on the psychological studies, but also based on the quantitative methods to arise the accuracy of recognitions. Also in this model, fuzzy logic and genetic algorithm are used to classify facial expressions. Genetic algorithm is an exclusive attribute of proposed model which is used for tuning membership functions and increasing the accuracy.

  5. Quantitative interferometric microscopy with two dimensional Hilbert transform based phase retrieval method

    Science.gov (United States)

    Wang, Shouyu; Yan, Keding; Xue, Liang

    2017-01-01

    In order to obtain high contrast images and detailed descriptions of label free samples, quantitative interferometric microscopy combining with phase retrieval is designed to obtain sample phase distributions from fringes. As accuracy and efficiency of recovered phases are affected by phase retrieval methods, thus approaches owning higher precision and faster processing speed are still in demand. Here, two dimensional Hilbert transform based phase retrieval method is adopted in cellular phase imaging, it not only reserves more sample specifics compared to classical fast Fourier transform based method, but also overcomes disadvantages of traditional algorithm according to Hilbert transform which is a one dimensional processing causing phase ambiguities. Both simulations and experiments are provided, proving the proposed phase retrieval approach can acquire quantitative sample phases with high accuracy and fast speed.

  6. A statistical framework for protein quantitation in bottom-up MS-based proteomics

    Energy Technology Data Exchange (ETDEWEB)

    Karpievitch, Yuliya; Stanley, Jeffrey R.; Taverner, Thomas; Huang, Jianhua; Adkins, Joshua N.; Ansong, Charles; Heffron, Fred; Metz, Thomas O.; Qian, Weijun; Yoon, Hyunjin; Smith, Richard D.; Dabney, Alan R.

    2009-08-15

    ABSTRACT Motivation: Quantitative mass spectrometry-based proteomics requires protein-level estimates and confidence measures. Challenges include the presence of low-quality or incorrectly identified peptides and widespread, informative, missing data. Furthermore, models are required for rolling peptide-level information up to the protein level. Results: We present a statistical model for protein abundance in terms of peptide peak intensities, applicable to both label-based and label-free quantitation experiments. The model allows for both random and censoring missingness mechanisms and provides naturally for protein-level estimates and confidence measures. The model is also used to derive automated filtering and imputation routines. Three LC-MS datasets are used to illustrate the methods. Availability: The software has been made available in the open-source proteomics platform DAnTE (Polpitiya et al. (2008)) (http://omics.pnl.gov/software/). Contact: adabney@stat.tamu.edu

  7. Synthesis and antimicrobial activities of new higher amino acid Schiff base derivatives of 6-aminopenicillanic acid and 7-aminocephalosporanic acid

    Science.gov (United States)

    Özdemir (nee Güngör), Özlem; Gürkan, Perihan; Özçelik, Berrin; Oyardı, Özlem

    2016-02-01

    Novel β-lactam derivatives (1c-3c) (1d-3d) were produced by using 6-aminopenicillanic acid (6-APA), 7-aminocephalosporanic acid (7-ACA) and the higher amino acid Schiff bases. The synthesized compounds were characterized by elemental analysis, IR, 1H/13C NMR and UV-vis spectra. Antibacterial activities of all the higher amino acid Schiff bases (1a-3a) (1b-3b) and β-lactam derivatives were screened against three gram negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Acinetobacter baumannii RSKK 02026), three gram positive bacteria (Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 07005, Bacillus subtilis ATCC 6633) and their drug-resistant isolates by using broth microdilution method. Two fungi (Candida albicans and Candida krusei) were used for antifungal activity.

  8. General (medium-chain) acyl-CoA dehydrogenase deficiency (non-ketotic dicarboxylic aciduria): quantitative urinary excretion pattern of 23 biologically significant organic acids in three cases.

    Science.gov (United States)

    Gregersen, N; Kølvraa, S; Rasmussen, K; Mortensen, P B; Divry, P; David, M; Hobolth, N

    1983-08-15

    Urinary analysis of the pattern of 23 organic acid metabolites derived from fatty acids in three patients with general (medium-chain) acyl-CoA dehydrogenase deficiency was performed. Although there exist quantitative differences in the excreted amounts of the different metabolites in the three patients the qualitative picture was the same. The excretion of adipic, suberic and sebacic acids was substantial, whereas that of dodecanedioic acid was within or just above control limit. The monounsaturated C6-C10-dicarboxylic acid excretion was only marginally or not increased. 5-OH-hexanoic acid and hexanoylglycine were excreted in excessive amounts, whereas 7-OH-octanoic acid, 9-OH-decanoic acid, octanoylglycine and decanoylglycine were excreted in limited amounts. The excreted amounts of 6-OH-hexanoic, 8-OH-octanoic and 10-OH-decanoic acids were not or only marginally elevated compared to controls. In one of the patients the excretion of ethylmalonic and methylsuccinic acids was enhanced, whereas the excretion of these two acids in the two other patients was comparable to that in controls. The urinary excretion of hexanoic, octanoic, decanoic and dodecanoic acids was just a little above the control limit, whereas the esterified hexanoic and octanoic acids were excreted in appreciable amounts. It is argued that the microsomal omega- and omega-1-oxidation systems are involved in the dicarboxylic and omega-1-OH-monocarboxylic acids formation at C10 and C12 level and that the C8-C6-dicarboxylic and omega-1-OH-monocarboxylic acids are formed from higher chained acids by beta-oxidation in both mitochondria and peroxisomes.

  9. 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.

  10. Kislinsko-bazno ravnovesje: Acid-base balance:

    OpenAIRE

    2002-01-01

    Acids are donors, while bases are acceptors of protons in solutions. Many various acids and bases are incorporated into organisms by everyday alimentation and cell metabolism, while the output routes are the respiratory system, kidneys and gastrointestinal system. The concentration of free protonsin the blood (expressed as pH value) is strictly regulated, as it has agreat impact on cell metabolism. There are many ways in which organisms defend themselves against harmful pH changes. The first ...

  11. Quantitative Verification of a Force-based Model for Pedestrian Dynamics

    CERN Document Server

    Chraibi, Mohcine; Schadschneider, Andreas; Mackens, Wolfgang

    2009-01-01

    This paper introduces a spatially continuous force-based model for simulating pedestrian dynamics. The main intention of this work is the quantitative description of pedestrian movement through bottlenecks and in corridors. Measurements of flow and density at bottlenecks will be presented and compared with empirical data. Furthermore the fundamental diagram for the movement in a corridor is reproduced. The results of the proposed model show a good agreement with empirical data.

  12. A quantitative model of human DNA base excision repair. I. mechanistic insights

    OpenAIRE

    Sokhansanj, Bahrad A.; Rodrigue, Garry R.; Fitch, J. Patrick; David M Wilson

    2002-01-01

    Base excision repair (BER) is a multistep process involving the sequential activity of several proteins that cope with spontaneous and environmentally induced mutagenic and cytotoxic DNA damage. Quantitative kinetic data on single proteins of BER have been used here to develop a mathematical model of the BER pathway. This model was then employed to evaluate mechanistic issues and to determine the sensitivity of pathway throughput to altered enzyme kinetics. Notably, the model predicts conside...

  13. Music-based interventions in palliative cancer care: a review of quantitative studies and neurobiological literature

    OpenAIRE

    Archie, Patrick; Bruera, Eduardo; Cohen, Lorenzo

    2013-01-01

    Purpose This study aimed to review quantitative literature pertaining to studies of music-based interventions in palliative cancer care and to review the neurobiological literature that may bare relevance to the findings from these studies. Methods A narrative review was performed, with particular emphasis on RCTs, meta-analyses, and systematic reviews. The Cochrane Library, Ovid, PubMed, CINAHL Plus, PsycINFO, and ProQuest were searched for the subject headings music, music therapy, cancer, ...

  14. Quantitative analysis of multiple components based on liquid chromatography with mass spectrometry in full scan mode.

    Science.gov (United States)

    Xu, Min Li; Li, Bao Qiong; Wang, Xue; Chen, Jing; Zhai, Hong Lin

    2016-08-01

    Although liquid chromatography with mass spectrometry in full scan mode can obtain all the signals simultaneously in a large range and low cost, it is rarely used in quantitative analysis due to several problems such as chromatographic drifts and peak overlap. In this paper, we propose a Tchebichef moment method for the simultaneous quantitative analysis of three active compounds in Qingrejiedu oral liquid based on three-dimensional spectra in full scan mode of liquid chromatography with mass spectrometry. After the Tchebichef moments were calculated directly from the spectra, the quantitative linear models for three active compounds were established by stepwise regression. All the correlation coefficients were more than 0.9978. The limits of detection and limits of quantitation were less than 0.11 and 0.49 μg/mL, respectively. The intra- and interday precisions were less than 6.54 and 9.47%, while the recovery ranged from 102.56 to 112.15%. Owing to the advantages of multi-resolution and inherent invariance properties, Tchebichef moments could provide favorable results even in the situation of peaks shifting and overlapping, unknown interferences and noise signals, so it could be applied to the analysis of three-dimensional spectra in full scan mode of liquid chromatography with mass spectrometry.

  15. A Quantitative Reasoning Approach to Algebra Using Inquiry-Based Learning

    Directory of Open Access Journals (Sweden)

    Victor I. Piercey

    2017-07-01

    Full Text Available In this paper, I share a hybrid quantitative reasoning/algebra two-course sequence that challenges the common assumption that quantitative literacy and reasoning are less rigorous mathematics alternatives to algebra and illustrates that a quantitative reasoning framework can be used to teach traditional algebra. The presentation is made in two parts. In the first part, which is somewhat philosophical and theoretical, I explain my personal perspective of what I mean by “algebra” and “doing algebra.” I contend that algebra is a form of communication whose value is precision, which allows us to perform algebraic manipulations in the form of simplification and solving moves. A quantitative reasoning approach to traditional algebraic manipulations rests on intentional and purposeful use of simplification and solving moves within contextual situations. In part 2, I describe a 6-week instructional module intended for undergraduate business students that was delivered to students who had placed into beginning algebra. The perspective described in part 1 heavily informed the design of this module. The course materials, which involve the use of Excel in multiple authentic contexts, are built around the use of inquiry-based learning. Upon completion of this module, the percentage of students who successfully complete model problems in an assessment is in the same range as surveyed students in precalculus and calculus, approximately two “grade levels” ahead of their placement.

  16. Quantitative profiling of polar metabolites in herbal medicine injections for multivariate statistical evaluation based on independence principal component analysis.

    Science.gov (United States)

    Jiang, Miaomiao; Jiao, Yujiao; Wang, Yuefei; Xu, Lei; Wang, Meng; Zhao, Buchang; Jia, Lifu; Pan, Hao; Zhu, Yan; Gao, Xiumei

    2014-01-01

    Botanical primary metabolites extensively exist in herbal medicine injections (HMIs), but often were ignored to control. With the limitation of bias towards hydrophilic substances, the primary metabolites with strong polarity, such as saccharides, amino acids and organic acids, are usually difficult to detect by the routinely applied reversed-phase chromatographic fingerprint technology. In this study, a proton nuclear magnetic resonance (1H NMR) profiling method was developed for efficient identification and quantification of small polar molecules, mostly primary metabolites in HMIs. A commonly used medicine, Danhong injection (DHI), was employed as a model. With the developed method, 23 primary metabolites together with 7 polyphenolic acids were simultaneously identified, of which 13 metabolites with fully separated proton signals were quantified and employed for further multivariate quality control assay. The quantitative 1H NMR method was validated with good linearity, precision, repeatability, stability and accuracy. Based on independence principal component analysis (IPCA), the contents of 13 metabolites were characterized and dimensionally reduced into the first two independence principal components (IPCs). IPC1 and IPC2 were then used to calculate the upper control limits (with 99% confidence ellipsoids) of χ2 and Hotelling T2 control charts. Through the constructed upper control limits, the proposed method was successfully applied to 36 batches of DHI to examine the out-of control sample with the perturbed levels of succinate, malonate, glucose, fructose, salvianic acid and protocatechuic aldehyde. The integrated strategy has provided a reliable approach to identify and quantify multiple polar metabolites of DHI in one fingerprinting spectrum, and it has also assisted in the establishment of IPCA models for the multivariate statistical evaluation of HMIs.

  17. Quantitative profiling of polar metabolites in herbal medicine injections for multivariate statistical evaluation based on independence principal component analysis.

    Directory of Open Access Journals (Sweden)

    Miaomiao Jiang

    Full Text Available Botanical primary metabolites extensively exist in herbal medicine injections (HMIs, but often were ignored to control. With the limitation of bias towards hydrophilic substances, the primary metabolites with strong polarity, such as saccharides, amino acids and organic acids, are usually difficult to detect by the routinely applied reversed-phase chromatographic fingerprint technology. In this study, a proton nuclear magnetic resonance (1H NMR profiling method was developed for efficient identification and quantification of small polar molecules, mostly primary metabolites in HMIs. A commonly used medicine, Danhong injection (DHI, was employed as a model. With the developed method, 23 primary metabolites together with 7 polyphenolic acids were simultaneously identified, of which 13 metabolites with fully separated proton signals were quantified and employed for further multivariate quality control assay. The quantitative 1H NMR method was validated with good linearity, precision, repeatability, stability and accuracy. Based on independence principal component analysis (IPCA, the contents of 13 metabolites were characterized and dimensionally reduced into the first two independence principal components (IPCs. IPC1 and IPC2 were then used to calculate the upper control limits (with 99% confidence ellipsoids of χ2 and Hotelling T2 control charts. Through the constructed upper control limits, the proposed method was successfully applied to 36 batches of DHI to examine the out-of control sample with the perturbed levels of succinate, malonate, glucose, fructose, salvianic acid and protocatechuic aldehyde. The integrated strategy has provided a reliable approach to identify and quantify multiple polar metabolites of DHI in one fingerprinting spectrum, and it has also assisted in the establishment of IPCA models for the multivariate statistical evaluation of HMIs.

  18. A contribution to the determination of aflatoxin B1, quinine hydrochloride and L(+)-ascorbic acid in foodstuffs by quantitative in situ thin-layer chromatographic analysis

    NARCIS (Netherlands)

    Beljaars, P.R.

    1974-01-01

    The application of quantitative thin-layer chromatography (TLC) involving in situ spectrodensitometric measurements with a flying-spot densitometer is described in this study for the analysis of aflatoxin B 1 , quinine hydrochloride and L(+)-ascorbic acid (vitamin C

  19. Genome-wide scan for bovine milk-fat composition. I. Quantitative trait loci for short- and medium-chain fatty acids

    NARCIS (Netherlands)

    Stoop, W.M.; Schennink, A.; Visker, M.H.P.W.; Mullaart, E.; Arendonk, van J.A.M.; Bovenhuis, H.

    2009-01-01

    A genome-wide scan was performed to identify quantitative trait loci (QTL) for short- and medium-chain fatty acids (expressed in wt/wt %). Milk samples were available from 1,905 cows from 398 commercial herds in the Netherlands, and milk-fat composition was measured by gas chromatography. DNA was av

  20. High-resolution gas chromatography/mas spectrometry method for characterization and quantitative analysis of ginkgolic acids in ginkgo biloba plants, extracts, and dietary supplements

    Science.gov (United States)

    A high resolution GC/MS with Selected Ion Monitor (SIM) method focusing on the characterization and quantitative analysis of ginkgolic acids (GAs) in Ginkgo biloba L. plant materials, extracts and commercial products was developed and validated. The method involved sample extraction with (1:1) meth...

  1. Short communication: Genome-wide scan for bovine milk-fat composition. II. Quantitative trait loci for long-chain fatty acids

    NARCIS (Netherlands)

    Schennink, A.; Stoop, W.M.; Visker, M.H.P.W.; Poel, van der J.J.; Bovenhuis, H.; Arendonk, van J.A.M.

    2009-01-01

    We present the results of a genome-wide scan to identify quantitative trait loci (QTL) that contribute to genetic variation in long-chain milk fatty acids. Milk-fat composition phenotypes were available on 1,905 Dutch Holstein-Friesian cows. A total of 849 cows and their 7 sires were genotyped for 1

  2. Prediction of quantitative phenotypes based on genetic networks: a case study in yeast sporulation

    Directory of Open Access Journals (Sweden)

    Shen Li

    2010-09-01

    Full Text Available Abstract Background An exciting application of genetic network is to predict phenotypic consequences for environmental cues or genetic perturbations. However, de novo prediction for quantitative phenotypes based on network topology is always a challenging task. Results Using yeast sporulation as a model system, we have assembled a genetic network from literature and exploited Boolean network to predict sporulation efficiency change upon deleting individual genes. We observe that predictions based on the curated network correlate well with the experimentally measured values. In addition, computational analysis reveals the robustness and hysteresis of the yeast sporulation network and uncovers several patterns of sporulation efficiency change caused by double gene deletion. These discoveries may guide future investigation of underlying mechanisms. We have also shown that a hybridized genetic network reconstructed from both temporal microarray data and literature is able to achieve a satisfactory prediction accuracy of the same quantitative phenotypes. Conclusions This case study illustrates the value of predicting quantitative phenotypes based on genetic network and provides a generic approach.

  3. MilQuant: a free, generic software tool for isobaric tagging-based quantitation.

    Science.gov (United States)

    Zou, Xiao; Zhao, Minzhi; Shen, Hongyan; Zhao, Xuyang; Tong, Yuanpeng; Wang, Qingsong; Wei, Shicheng; Ji, Jianguo

    2012-09-18

    Isobaric tagging techniques such as iTRAQ and TMT are widely used in quantitative proteomics and especially useful for samples that demand in vitro labeling. Due to diversity in choices of MS acquisition approaches, identification algorithms, and relative abundance deduction strategies, researchers are faced with a plethora of possibilities when it comes to data analysis. However, the lack of generic and flexible software tool often makes it cumbersome for researchers to perform the analysis entirely as desired. In this paper, we present MilQuant, mzXML-based isobaric labeling quantitator, a pipeline of freely available programs that supports native acquisition files produced by all mass spectrometer types and collection approaches currently used in isobaric tagging based MS data collection. Moreover, aside from effective normalization and abundance ratio deduction algorithms, MilQuant exports various intermediate results along each step of the pipeline, making it easy for researchers to customize the analysis. The functionality of MilQuant was demonstrated by four distinct datasets from different laboratories. The compatibility and extendibility of MilQuant makes it a generic and flexible tool that can serve as a full solution to data analysis of isobaric tagging-based quantitation.

  4. Speed limits for acid-base chemistry in aqueous solutions.

    Science.gov (United States)

    Donten, Mateusz L; Vandevondele, Joost; Hamm, Peter

    2012-01-01

    Proton transfer reactions, including acid-base recombination, are commonly considered to occur 'nearly instantaneously'. However, their actual time scales may stretch far into the microsecond range, as acid-base reactions are diffusion controlled and the concentrations are low near neutral pH. The interplay of competing bases in the pH relaxation is illustrated using a model acid-base system consisting of o-nitrobenzaldehyde (oNBA) as a proton cage and acetate ions and hydroxyl ions as bases. The kinetically controlled behavior leads to highly counterintuitive states, i.e. acetate ions are transiently protonated for hundreds of nanoseconds despite the presence of a much stronger base OH-.

  5. SWATH-MS Quantitative Proteomic Investigation Reveals a Role of Jasmonic Acid during Lead Response in Arabidopsis.

    Science.gov (United States)

    Zhu, Fu-Yuan; Chan, Wai-Lung; Chen, Mo-Xian; Kong, Ricky P W; Cai, Congxi; Wang, Qiaomei; Zhang, Jian-Hua; Lo, Clive

    2016-10-07

    Lead (Pb) pollution is a growing environment problem that continuously threatens the productivity of crops. To understand the molecular mechanisms of plant adaptation to Pb toxicity, we examined proteome changes in Arabidopsis seedlings following Pb treatment by SWATH-MS, a label-free quantitative proteomic platform. We identified and quantified the expression of 1719 proteins in water- and Pb-treated plants. Among them, 231 proteins showed significant abundance changes (151 elevated and 80 reduced) upon Pb exposure. Functional categorization revealed that most of the Pb-responsive proteins are involved in different metabolic processes. For example, down-regulation of photosynthesis and biosynthesis of isoprenoids and tetrapyrroles in chloroplasts were observed. On the contrary, pathways leading to glutathione, jasmonic acid (JA), glucosinolate (GSL), and phenylpropanoid production are up-regulated. Experimental characterizations demonstrated a rapid elevation of endogenic JA production in Pb-treated Arabidopsis seedlings, while a JA-deficient mutant and a JA-insensitive mutant showed hypersensitivity to root inhibition by Pb, implicating an essential role of JA during Pb responses. Consistently, methyl jasmonate supplementation alleviated Pb toxicity in the wild-type and JA-deficient mutant. Furthermore, GSL levels were substantially enhanced following Pb treatment, while such induction was not detected in the JA mutant, suggesting that the Pb-induced GSL accumulation is JA-dependent. Overall, our work represents the first SWATH-MS analysis in Arabidopsis and highlights a potential mediating role of JA during Pb stress.

  6. Comparison of colorimetric assays with quantitative amino acid analysis for protein quantification of Generalized Modules for Membrane Antigens (GMMA).

    Science.gov (United States)

    Rossi, Omar; Maggiore, Luana; Necchi, Francesca; Koeberling, Oliver; MacLennan, Calman A; Saul, Allan; Gerke, Christiane

    2015-01-01

    Genetically induced outer membrane particles from Gram-negative bacteria, called Generalized Modules for Membrane Antigens (GMMA), are being investigated as vaccines. Rapid methods are required for estimating the protein content for in-process assays during production. Since GMMA are complex biological structures containing lipid and polysaccharide as well as protein, protein determinations are not necessarily straightforward. We compared protein quantification by Bradford, Lowry, and Non-Interfering assays using bovine serum albumin (BSA) as standard with quantitative amino acid (AA) analysis, the most accurate currently available method for protein quantification. The Lowry assay has the lowest inter- and intra-assay variation and gives the best linearity between protein amount and absorbance. In all three assays, the color yield (optical density per mass of protein) of GMMA was markedly different from that of BSA with a ratio of approximately 4 for the Bradford assay, and highly variable between different GMMA; and approximately 0.7 for the Lowry and Non-Interfering assays, highlighting the need for calibrating the standard used in the colorimetric assay against GMMA quantified by AA analysis. In terms of a combination of ease, reproducibility, and proportionality of protein measurement, and comparability between samples, the Lowry assay was superior to Bradford and Non-Interfering assays for GMMA quantification.

  7. Fluorogenic Tagging of Peptide and Protein 3-Nitrotyrosine with 4-(Aminomethyl)-benzenesulfonic Acid for Quantitative Analysis of Protein Tyrosine Nitration.

    Science.gov (United States)

    Sharov, Victor S; Dremina, Elena S; Galeva, Nadezhda A; Gerstenecker, Gary S; Li, Xiaobao; Dobrowsky, Rick T; Stobaugh, John F; Schöneich, Christian

    2010-01-01

    Protein 3-nitrotyrosine (3-NT) has been recognized as an important biomarker of nitroxidative stress associated with inflammatory and degenerative diseases, and biological aging. Analysis of protein-bound 3-NT continues to represent a challenge since in vivo it frequently does not accumulate on proteins in amounts detectable by quantitative analytical methods. Here, we describe a novel approach of fluorescent tagging and quantitation of peptide-bound 3-NT residues based on the selective reduction to 3-AT followed by reaction with 4-(amino-methyl)benzenesulfonic acid (ABS) in the presence of K(3)Fe(CN)(6) to form a highly fluorescent 2-phenylbenzoxazole product. Synthetic 3-NT peptide (0.005-1 μM) upon reduction with 10 mM sodium dithionite and tagging with 2 mM ABS and 5 μM K(3)Fe(CN)(6) in 0.1 M Na(2)HPO(4) buffer (pH 9.0) was converted with yields >95% to a single fluorescent product incorporating two ABS molecules per 3-NT residue, with fluorescence excitation and emission maxima at 360 ± 2 and 490 ± 2 nm, respectively, and a quantum yield of 0.77 ± 0.08, based on reverse-phase LC with UV and fluorescence detection, fluorescence spectroscopy and LC-MS-MS analysis. This protocol was successfully tested for quantitative analysis of in vitro Tyr nitration in a model protein, rabbit muscle phosphorylase b, and in a complex mixture of proteins from C2C12 cultured cells exposed to peroxynitrite, with a detection limit of ca. 1 pmol 3-NT by fluorescence spectrometry, and an apparent LOD of 12 and 40 pmol for nitropeptides alone or in the presence of 100 μg digested cell proteins, respectively. LC-MS-MS analysis of ABS tagged peptides revealed that the fluorescent derivatives undergo efficient backbone fragmentations, allowing for sequence-specific characterization of protein Tyr nitration in proteomic studies. Fluorogenic tagging with ABS also can be instrumental for detection and visualization of protein 3-NT in LC and gel-based protein separations.

  8. Quantitative comparison of caffeoylquinic acids and flavonoids in Chrysanthemum morifolium flowers and their sulfur-fumigated products by three-channel liquid chromatography with electrochemical detection.

    Science.gov (United States)

    Chen, Liangmian; Kotani, Akira; Kusu, Fumiyo; Wang, Zhimin; Zhu, Jingjing; Hakamata, Hideki

    2015-01-01

    For the determination of seven caffeoylquinic acids [neochlorogenic acid (NcA), cryptochlorogenic acid (CcA), chlorogenic acid (CA), caffeic acid (CfA), isochlorogenic acid A (Ic A), isochlorogenic acid B (Ic B), isochlorogenic acid C (Ic C)] and two flavonoids [luteolin 7-O-glucoside (LtG) and luteolin (Lt)], a three-channel liquid chromatography with electrochemical detection (LC-3ECD) method was established. Chromatographic peak heights were proportional to each concentration, ranging from 2.5 to 100 ng/mL for NcA, CA, CcA, and CfA, and ranging from 2.5 to 250 ng/mL for LtG, Ic B, Ic A, Ic C, and Lt, respectively. The present LC-3ECD method was applied to the quantitative analysis of caffeoylquinic acids and flavonoids in four cultivars of Chrysanthemum morifolium flowers and their sulfur-fumigated products. It was found that 60% of LtG and more than 47% of caffeoylquinic acids were lost during the sulfur fumigation processing. Sulfur fumigation showed a destructive effect on the C. morifolium flowers. In addition, principle component analyses (PCA) were performed using the results of the quantitative analysis of caffeoylquinic acids and flavonoids to compare the "sameness" and "differences" of these analytes in C. morifolium flowers and the sulfur-fumigated products. PCA score plots showed that the four cultivars of C. morifolium flowers were clearly classified into four groups, and that significant differences were also found between the non-fumigated C. morifolium flowers and the sulfur-fumigated products. Therefore, it was demonstrated that the present LC-3ECD method coupled with PCA is applicable to the variation analysis of different C. morifolium flower samples.

  9. Scientifically Based Research in Quantitative Literacy: Guidelines for Building a Knowledge Base

    OpenAIRE

    Richard L. Scheaffer

    2008-01-01

    Research in quantitative literacy (QL) is in its infancy, so now is the time to begin a regimen for healthy growth into adulthood. As a new discipline still defining itself, QL has the opportunity to build a sound infrastructure for accumulating a solid body of interconnected research that will serve the discipline well in years to come. To that end, much can be learned from recent studies of the weaknesses of mathematics education research and recommendations on how to overcome them. Mathema...

  10. tRNA acceptor-stem and anticodon bases embed separate features of amino acid chemistry.

    Science.gov (United States)

    Carter, Charles W; Wolfenden, Richard

    2016-01-01

    The universal genetic code is a translation table by which nucleic acid sequences can be interpreted as polypeptides with a wide range of biological functions. That information is used by aminoacyl-tRNA synthetases to translate the code. Moreover, amino acid properties dictate protein folding. We recently reported that digital correlation techniques could identify patterns in tRNA identity elements that govern recognition by synthetases. Our analysis, and the functionality of truncated synthetases that cannot recognize the tRNA anticodon, support the conclusion that the tRNA acceptor stem houses an independent code for the same 20 amino acids that likely functioned earlier in the emergence of genetics. The acceptor-stem code, related to amino acid size, is distinct from a code in the anticodon that is related to amino acid polarity. Details of the acceptor-stem code suggest that it was useful in preserving key properties of stereochemically-encoded peptides that had developed the capacity to interact catalytically with RNA. The quantitative embedding of the chemical properties of amino acids into tRNA bases has implications for the origins of molecular biology.

  11. A novel quantitative imaging technique for material differentiation based on differential phase contrast CT

    Science.gov (United States)

    Qi, Zhihua; Zambelli, Joseph; Bevins, Nicholas; Chen, Guang-Hong

    2010-04-01

    Compared to single energy CT, which provides information only about the x-ray linear attenuation coefficients, dual energy CT is able to obtain the electron density and effective atomic number for different materials in a quantitative way. In this study, as an alternative to dual energy CT, a novel quantitative imaging method based on phase contrast CT is described. Rather than requiring two scans with different x-ray photon energies, diffraction grating-based phase contrast CT is capable of reconstructing images of both the linear attenuation and refractive index decrement from a single scan. From the two images, quantitative information of both the electron density and effective atomic number can be extracted. Experimental results demonstrate that: (1) electron density can be accurately determined from refractive index decrement through a linear relationship; and (2) effective atomic number can be explicitly derived from the ratio of linear attenuation to refractive index decrement, using a simple function, i.e., a power function plus a constant. The presented method will shed insight into the field of material separation and find its use in medical and non-medical applications.

  12. Quantitative design of regulatory elements based on high-precision strength prediction using artificial neural network.

    Science.gov (United States)

    Meng, Hailin; Wang, Jianfeng; Xiong, Zhiqiang; Xu, Feng; Zhao, Guoping; Wang, Yong

    2013-01-01

    Accurate and controllable regulatory elements such as promoters and ribosome binding sites (RBSs) are indispensable tools to quantitatively regulate gene expression for rational pathway engineering. Therefore, de novo designing regulatory elements is brought back to the forefront of synthetic biology research. Here we developed a quantitative design method for regulatory elements based on strength prediction using artificial neural network (ANN). One hundred mutated Trc promoter & RBS sequences, which were finely characterized with a strength distribution from 0 to 3.559 (relative to the strength of the original sequence which was defined as 1), were used for model training and test. A precise strength prediction model, NET90_19_576, was finally constructed with high regression correlation coefficients of 0.98 for both model training and test. Sixteen artificial elements were in silico designed using this model. All of them were proved to have good consistency between the measured strength and our desired strength. The functional reliability of the designed elements was validated in two different genetic contexts. The designed parts were successfully utilized to improve the expression of BmK1 peptide toxin and fine-tune deoxy-xylulose phosphate pathway in Escherichia coli. Our results demonstrate that the methodology based on ANN model can de novo and quantitatively design regulatory elements with desired strengths, which are of great importance for synthetic biology applications.

  13. A remote quantitative Fugl-Meyer assessment framework for stroke patients based on wearable sensor networks.

    Science.gov (United States)

    Yu, Lei; Xiong, Daxi; Guo, Liquan; Wang, Jiping

    2016-05-01

    To extend the use of wearable sensor networks for stroke patients training and assessment in non-clinical settings, this paper proposes a novel remote quantitative Fugl-Meyer assessment (FMA) framework, in which two accelerometer and seven flex sensors were used to monitoring the movement function of upper limb, wrist and fingers. The extreme learning machine based ensemble regression model was established to map the sensor data to clinical FMA scores while the RRelief algorithm was applied to find the optimal features subset. Considering the FMA scale is time-consuming and complicated, seven training exercises were designed to replace the upper limb related 33 items in FMA scale. 24 stroke inpatients participated in the experiments in clinical settings and 5 of them were involved in the experiments in home settings after they left the hospital. Both the experimental results in clinical and home settings showed that the proposed quantitative FMA model can precisely predict the FMA scores based on wearable sensor data, the coefficient of determination can reach as high as 0.917. It also indicated that the proposed framework can provide a potential approach to the remote quantitative rehabilitation training and evaluation.

  14. Quantitative analysis of caffeic and ferulic acids in oatmeal. Comparison of a conventional method with a stable isotope dilution assay.

    Science.gov (United States)

    Guth, H; Grosch, W

    1994-09-01

    [13C]Caffeic acid and [13C]ferulic acid were synthesized and then used as internal standards for the determination of these acids (free and esterified) in oatmeal. A comparative study indicated that 84% of the ferulic acid, but only 32% of the caffeic acid, which is more susceptible to oxidation than the former, could be found by a conventional analytical approach.

  15. Quantitative detection of defects based on Markov-PCA-BP algorithm using pulsed infrared thermography technology

    Science.gov (United States)

    Tang, Qingju; Dai, Jingmin; Liu, Junyan; Liu, Chunsheng; Liu, Yuanlin; Ren, Chunping

    2016-07-01

    Quantitative detection of debonding defects' diameter and depth in TBCs has been carried out using pulsed infrared thermography technology. By combining principal component analysis with neural network theory, the Markov-PCA-BP algorithm was proposed. The principle and realization process of the proposed algorithm was described. In the prediction model, the principal components which can reflect most characteristics of the thermal wave signal were set as the input, and the defect depth and diameter was set as the output. The experimental data from pulsed infrared thermography tests of TBCs with flat bottom hole defects was selected as the training and testing sample. Markov-PCA-BP predictive system was arrived, based on which both the defect depth and diameter were identified accurately, which proved the effectiveness of the proposed method for quantitative detection of debonding defects in TBCs.

  16. [Quantitative specific detection of Staphylococcus aureus based on recombinant lysostaphin and ATP bioluminescence].

    Science.gov (United States)

    Li, Yuyuan; Mi, Zhiqiang; An, Xiaoping; Zhou, Yusen; Tong, Yigang

    2014-08-01

    Quantitative specific detection of Staphylococcus aureus is based on recombinant lysostaphin and ATP bioluminescence. To produce recombinant lysostaphin, the lysostaphin gene was chemically synthesized and inserted it into prokaryotic expression vector pQE30, and the resulting expression plasmid pQE30-Lys was transformed into E. coli M15 for expressing lysostaphin with IPTG induction. The recombinant protein was purified by Ni(2+)-NTA affinity chromatography. Staphylococcus aureus was detected by the recombinant lysostaphin with ATP bioluminescence, and plate count method. The results of the two methods were compared. The recombinant lysostaphin was successfully expressed, and a method of quantitative specific detection of S. aureus has been established, which showed a significant linear correlation with the colony counting. The detection method developed has good perspective to quantify S. aureus.

  17. Quantitative Profiling of Long-Chain Bases by Mass Tagging and Parallel Reaction Monitoring

    DEFF Research Database (Denmark)

    Ejsing, Christer S; Bilgin, Mesut; Fabregat, Andreu

    2015-01-01

    Long-chain bases (LCBs) are both intermediates in sphingolipid metabolism and potent signaling molecules that control cellular processes. To understand how regulation of sphingolipid metabolism and levels of individual LCB species impinge upon physiological and pathophysiological processes requires...... sensitive and specific assays for monitoring these molecules. Here we describe a shotgun lipidomics method for quantitative profiling of LCB molecules. The method employs a "mass-tag" strategy where LCBs are chemically derivatized with deuterated methyliodide (CD3I) to produce trimethylated derivatives...... having a positively charged quaternary amine group. This chemical derivatization minimizes unwanted in-source fragmentation of LCB analytes and prompts a characteristic trimethylaminium fragment ion that enables sensitive and quantitative profiling of LCB molecules by parallel reaction monitoring...

  18. Primer design using Primer Express® for SYBR Green-based quantitative PCR.

    Science.gov (United States)

    Singh, Amarjeet; Pandey, Girdhar K

    2015-01-01

    To quantitate the gene expression, real-time RT-PCR or quantitative PCR (qPCR) is one of the most sensitive, reliable, and commonly used methods in molecular biology. The reliability and success of a real-time PCR assay depend on the optimal experiment design. Primers are the most important constituents of real-time PCR experiments such as in SYBR Green-based detection assays. Designing of an appropriate and specific primer pair is extremely crucial for correct estimation of transcript abundance of any gene in a given sample. Here, we are presenting a quick, easy, and reliable method for designing target-specific primers using Primer Express(®) software for real-time PCR (qPCR) experiments.

  19. A new quantitative model of ecological compensation based on ecosystem capital in Zhejiang Province, China.

    Science.gov (United States)

    Jin, Yan; Huang, Jing-feng; Peng, Dai-liang

    2009-04-01

    Ecological compensation is becoming one of key and multidiscipline issues in the field of resources and environmental management. Considering the change relation between gross domestic product (GDP) and ecological capital (EC) based on remote sensing estimation, we construct a new quantitative estimate model for ecological compensation, using county as study unit, and determine standard value so as to evaluate ecological compensation from 2001 to 2004 in Zhejiang Province, China. Spatial differences of the ecological compensation were significant among all the counties or districts. This model fills up the gap in the field of quantitative evaluation of regional ecological compensation and provides a feasible way to reconcile the conflicts among benefits in the economic, social, and ecological sectors.

  20. Simultaneous quantitation of folic acid and 5-methyltetrahydrofolic acid in human plasma by HPLC-MS/MS and its application to a pharmacokinetic study☆

    Institute of Scientific and Technical Information of China (English)

    Xiao-Hong Zheng; Li-Yuan Jiang; Lan-Ting Zhao; Quan-Ying Zhang; Li Ding

    2015-01-01

    A sensitive method based on high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the simultaneous determination of folic acid (FA) and its active metabolite, 5-methyltetrahydrofolic acid (5-M-THF), in human plasma. The analytes were extracted from plasma with methanol solution containing 10 mg/mL of 2-mercaptoethanol and 0.025% (v/v) ammonium hydroxide. FA and 5-M-THF were more stable after the addition of 2-mercaptoethanol and ammonium hydroxide in the sample preparation procedures of this study than they were in the previously published methods. Chromatographic separation was performed on a Hedera ODS-2 column using a gradient elution system of acetonitrile and 1 mM ammonium acetate buffer solution containing 0.6% formic acid as mobile phase. LC-MS/MS was carried out with an ESI ion-source and operated in the multiple reaction monitoring (MRM) mode. The assay was linear over the concentration ranges of 0.249-19.9 ng/mL for FA, and 5.05-50.5 ng/mL for 5-M-THF. The developed LC-MS/MS method offers increased sensitivity for quantification of FA and 5-M-THF in human plasma and was applicable to a pharmacokinetic study of FA and 5-M-THF.

  1. Assessing the performance capabilities of LRE-based assays for absolute quantitative real-time PCR.

    Directory of Open Access Journals (Sweden)

    Robert G Rutledge

    Full Text Available BACKGROUND: Linear regression of efficiency or LRE introduced a new paradigm for conducting absolute quantification, which does not require standard curves, can generate absolute accuracies of +/-25% and has single molecule sensitivity. Derived from adapting the classic Boltzmann sigmoidal function to PCR, target quantity is calculated directly from the fluorescence readings within the central region of an amplification profile, generating 4-8 determinations from each amplification reaction. FINDINGS: Based on generating a linear representation of PCR amplification, the highly visual nature of LRE analysis is illustrated by varying reaction volume and amplification efficiency, which also demonstrates how LRE can be used to model PCR. Examining the dynamic range of LRE further demonstrates that quantitative accuracy can be maintained down to a single target molecule, and that target quantification below ten molecules conforms to that predicted by Poisson distribution. Essential to the universality of optical calibration, the fluorescence intensity generated by SYBR Green I (FU/bp is shown to be independent of GC content and amplicon size, further verifying that absolute scale can be established using a single quantitative standard. Two high-performance lambda amplicons are also introduced that in addition to producing highly precise optical calibrations, can be used as benchmarks for performance testing. The utility of limiting dilution assay for conducting platform-independent absolute quantification is also discussed, along with the utility of defining assay performance in terms of absolute accuracy. CONCLUSIONS: Founded on the ability to exploit lambda gDNA as a universal quantitative standard, LRE provides the ability to conduct absolute quantification using few resources beyond those needed for sample preparation and amplification. Combined with the quantitative and quality control capabilities of LRE, this kinetic-based approach has the

  2. 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.

  3. The effect of antioxidants on quantitative changes of lysine and methionine in linoleic acid emulsions at different pH conditions

    Directory of Open Access Journals (Sweden)

    Marzanna Hęś

    2017-03-01

    Full Text Available Background. Plants are an important source of phenolic compounds. The antioxidant capacities of green tea, thyme and rosemary extracts that contain these compounds have been reported earlier. However, there is a lack of accessible information about their activity against lipid oxidation in emulsions and inhibit the interaction of lipid oxidation products with amino acids. Therefore, the influence of green tea, thyme and rosemary extracts and BHT (butylated hydroxytoluene on quantitative changes in lysine and methionine in linoleic acid emulsions at a pH of isoelectric point and a pH lower than the isoelectric point of amino acids was investigated. Material and methods. Total phenolic contents in plant extracts were determined spectrophotometrically by using Folin-Ciocalteu’s reagent, and individual phenols by using HPLC. The level of oxidation of emulsion was determined using the measurement of peroxides and TBARS (thiobarbituric acid reactive substances. Methionine and lysine in the system were reacted with sodium nitroprusside and trinitrobenzenesulphonic acid respectively, and the absorbance of the complexes was measured. Results. Extract of green tea had the highest total polyphenol content. The system containing antioxidants and amino acid protected linoleic acid more efficiently than by the addition of antioxidants only. Lysine and methionine losses in samples without the addition of antioxidants were lower in their isoelectric points than below these points. Antioxidants decrease the loss of amino acids. The protective properties of antioxidants towards methionine were higher in a pH of isoelectric point whereas towards lysine in pH below this point. Conclusion. Green tea, thyme and rosemary extracts exhibit antioxidant activity in linoleic acid emulsions. Moreover, they can be utilized to inhibit quantitative changes in amino acids in lipid emulsions. However, the antioxidant efficiency of these extracts seems to depend on p

  4. The effect of antioxidants on quantitative changes of lysine and methionine in linoleic acid emulsions at different pH conditions.

    Science.gov (United States)

    Hęś, Marzanna; Gliszczyńska-Świgło, Anna; Gramza-Michałowska, Anna

    2017-01-01

    Plants are an important source of phenolic compounds. The antioxidant capacities of green tea, thyme and rosemary extracts that contain these compounds have been reported earlier. However, there is a lack of accessible information about their activity against lipid oxidation in emulsions and inhibit the interaction of lipid oxidation products with amino acids. Therefore, the influence of green tea, thyme and rosemary extracts and BHT (butylated hydroxytoluene) on quantitative changes in lysine and methionine in linoleic acid emulsions at a pH of isoelectric point and a pH lower than the isoelectric point of amino acids was investigated. Total phenolic contents in plant extracts were determined spectrophotometrically by using Folin-Ciocalteu's reagent, and individual phenols by using HPLC. The level of oxidation of emulsion was determined using the measurement of peroxides and TBARS (thiobarbituric acid reactive substances). Methionine and lysine in the system were reacted with sodium nitroprusside and trinitrobenzenesulphonic acid respectively, and the absorbance of the complexes was measured. Extract of green tea had the highest total polyphenol content. The system containing antioxidants and amino acid protected linoleic acid more efficiently than by the addition of antioxidants only. Lysine and methionine losses in samples without the addition of antioxidants were lower in their isoelectric points than below these points. Antioxidants decrease the loss of amino acids. The protective properties of antioxidants towards methionine were higher in a pH of isoelectric point whereas towards lysine in pH below this point. Green tea, thyme and rosemary extracts exhibit antioxidant activity in linoleic acid emulsions. Moreover, they can be utilized to inhibit quantitative changes in amino acids in lipid emulsions. However, the antioxidant efficiency of these extracts seems to depend on pH conditions. Further investigations should be carried out to clarify this issue.

  5. Role of acids and bases in nanoparticle growth

    Science.gov (United States)

    Yli-Juuti, Taina; Barsanti, Kelley; Bzdek, Bryan; Hildebrandt Ruiz, Lea; Jokinen, Tuija; Kieloaho, Antti-Jussi; Makkonen, Ulla; Petäjä, Tuukka; Ruuskanen, Taina; Johnston, Murray; Kulmala, Markku; Riipinen, Ilona

    2014-05-01

    Secondary aerosol particles that are formed in atmosphere by gas-to-particle conversion during new particle formation events have potential to affect climate significantly due to their typically high number concentrations. This, however, requires that the freshly formed nanoparticles of about 1 nm in diameter grow tens of nanometers and reach climatically relevant sizes, i.e. sizes where they can act as cloud condensation nuclei. During the growth towards larger sizes the nanoparticles are subject to coagulational losses, and the rate at which the nanoparticles grow by condensation of vapors is a key factor affecting their probability to survive to climatically relevant sizes. Vapors that condense on the nanoparticles can be produced in the atmosphere from volatile compounds through gas phase chemical reactions, and their volatility can also be further lowered by particle phase processes. Therefore, particle composition and particle phase processes may influence nanoparticle growth. We study the growth of atmospheric nanoparticles and especially the role of particle phase salt formation in the nanoparticle growth using MABNAG model (Model for Acid-Base chemistry in NAnoparticle Growth) and by comparing to atmospheric measurements. MABNAG is a condensation growth model for aqueous solution particles. In MABNAG the dynamics of gas phase mass transport of vapors to particle are coupled with thermodynamics of particle phase acid-base chemistry, and both the composition and size dependence of equilibrium vapor pressures are accounted for. The model is applied especially for boreal forest environment. Here nanoparticle growth is modeled with a system of water, two acids (sulfuric acid and an organic acid) and two bases (ammonia and an amine) as condensing vapors. Focus is on the neutralization of acids by the bases and the related effects on the particle growth. According to the model predictions the enhancement of condensation of organic acid due to salt formation is

  6. Poly (ricinoleic acid) based novel thermosetting elastomer.

    Science.gov (United States)

    Ebata, Hiroki; Yasuda, Mayumi; Toshima, Kazunobu; Matsumura, Shuichi

    2008-01-01

    A novel bio-based thermosetting elastomer was prepared by the lipase-catalyzed polymerization of methyl ricinoleate with subsequent vulcanization. Some mechanical properties of the cured carbon black-filled polyricinoleate compounds were evaluated as a thermosetting elastomer. It was found that the carbon black-filled polyricinoleate compounds were readily cured by sulfur curatives to produce a thermosetting elastomer that formed a rubber-like sheet with a smooth and non-sticky surface. The curing behaviors and mechanical properties were dependent on both the molecular weight of the polyricinoleate and the amount of the sulfur curatives. Cured compounds consisting of polyricinoleate with a molecular weight of 100,800 showed good mechanical properties, such as a hardness of 48 A based on the durometer A measurements, a tensile strength at break of 6.91 MPa and an elongation at break of 350%.

  7. 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.

  8. Multi-wavelength spectrophotometric determination of acidity constant of some newly synthesized Schiff bases and their QSPR study.

    Science.gov (United States)

    Hemmateenejad, Bahram; Emami, Leila; Sharghi, Hashem

    2010-01-01

    The acidity constants of some newly synthesized Schiff base derivatives were determined by hard-model based multivariate data analysis of the spectrophotometric data in the course of pH-metric titration in 50% (v/v) methanol-water binary solvent. The employed data analysis method was also able to extract the pure spectra and pH-dependent concentration profiles of the acid-base species. The molecules that possess different substituents (both electron donating and withdrawing) on the ortho-, meta- and para-positions of one of the phenyl ring showed variable acidity constants ranging from 8.77 to 11.07 whereas the parent molecule had an acidity constant of 10.25. To investigate the quantitative effects of changing of substitution pattern on the acidity constant, a quantitative structure-property relation analysis was conducted using substituent constants and molecular descriptor. Some models with high statistical quality (measured by cross-validation Q(2)) were obtained. It was found that the acidity constant of the studied molecules in the methanol-water mixed solvent not only is affected by electronic features of the solutes but also by the lipophilic interaction between methanol part of solvent and the deprotonated solutes. Copyright 2009 Elsevier B.V. All rights reserved.

  9. Simultaneous qualitative and quantitative analysis of phenolic acids and flavonoids for the quality control of Apocynum venetum L. leaves by HPLC-DAD-ESI-IT-TOF-MS and HPLC-DAD.

    Science.gov (United States)

    An, Haijuan; Wang, Hong; Lan, Yuexiang; Hashi, Yuki; Chen, Shizhong

    2013-11-01

    A reliable method based on high performance liquid chromatography-diode array detector-electrospray ionization-ion trap-time of flight-mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) was developed for the identification of phenolic acids and flavonoids in Apocynum venetum L. leaves and its adulterant, Pocynum hendersonii (Hook. f.) Woodson leaves. A total of 21 compounds were identified or tentatively identified, including 4 phenolic acids and 17 flavonoids. 3-O-caffeoylquinic acid (3-CQA) and caffeic acid were detected for the first time in A. venetum leaves; 4-O-caffeoylquinic acid (4-CQA), 3-CQA, caffeic acid, quercetin-3-O-(6"-O-malonyl)-galactoside, quercetin-3-O-(6"-O-malonyl)-glucoside, kaempferol-3-O-(6"-O-malonyl)-glucoside, kaempferol-3-O-(6"-O-acetyl)-glucoside, and kaempferol-3-O-dihexoside were detected for the first time in P. hendersonii leaves. Cluster analysis was employed to analyze 24 batches of A. venetum leaves and 5 batches of P. hendersonii leaves collected from various regions in China. The analysis, which was based on the 21 compounds, indicated that profiles of these compounds were distinct between the two species, and among A. venetum leaf samples from different origins. 18 of these 21 compounds were selected as the markers and simultaneously analyzed by HPLC-DAD for the first time. The quantitative analytical method was validated and subsequently applied to the comprehensive quality evaluation of 24 batches of A. venetum leaves.

  10. 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....

  11. Nanopore-based sequencing and detection of nucleic acids.

    Science.gov (United States)

    Ying, Yi-Lun; Zhang, Junji; Gao, Rui; Long, Yi-Tao

    2013-12-09

    Nanopore-based techniques, which mimic the functions of natural ion channels, have attracted increasing attention as unique methods for single-molecule detection. The technology allows the real-time, selective, high-throughput analysis of nucleic acids through both biological and solid-state nanopores. In this Minireview, the background and latest progress in nanopore-based sequencing and detection of nucleic acids are summarized, and light is shed on a novel platform for nanopore-based detection. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Parallel proton transfer pathways in aqueous acid-base reactions

    NARCIS (Netherlands)

    Cox, M.J.; Bakker, H.J.

    2008-01-01

    We study the mechanism of proton transfer (PT) between the photoacid 8-hydroxy-1,3, 6-pyrenetrisulfonic acid (HPTS) and the base chloroacetate in aqueous solution. We investigate both proton and deuteron transfer reactions in solutions with base concentrations ranging from 0.25M to 4M. Using femtose

  13. Soil Studies: Applying Acid-Base Chemistry to Environmental Analysis.

    Science.gov (United States)

    West, Donna M.; Sterling, Donna R.

    2001-01-01

    Laboratory activities for chemistry students focus attention on the use of acid-base chemistry to examine environmental conditions. After using standard laboratory procedures to analyze soil and rainwater samples, students use web-based resources to interpret their findings. Uses CBL probes and graphing calculators to gather and analyze data and…

  14. Soil Studies: Applying Acid-Base Chemistry to Environmental Analysis.

    Science.gov (United States)

    West, Donna M.; Sterling, Donna R.

    2001-01-01

    Laboratory activities for chemistry students focus attention on the use of acid-base chemistry to examine environmental conditions. After using standard laboratory procedures to analyze soil and rainwater samples, students use web-based resources to interpret their findings. Uses CBL probes and graphing calculators to gather and analyze data and…

  15. The coulometric titration of acids and bases in dimethylsulfoxide media

    NARCIS (Netherlands)

    Bos, M.; IJpma, S.T.; Dahmen, E.A.M.F.

    1976-01-01

    The coulometric titration of 20–200 μeq of acids and bases in DMSO media is described. In the titration of bases, the electro-oxidation of hydrogen at a platinized platinum electrode is used as the source of protons. The conditions for 100 % current efficiency at this electrode are low current

  16. A European Acid Rain Program based on the US experience

    DEFF Research Database (Denmark)

    Brandt, U. Steiner; Svendsen, Gert Tinggaard

    2000-01-01

    The paper shows that cost-effective involvement of the source location involves utmost difficulty in practice. Based on the RAINS model, it is recommended that source location should be ignored in a European market for SO2, as is the case in the US Acid Rain Program. Based on the political target...

  17. Rapid and quantitative detection of C-reactive protein based on quantum dots and immunofiltration assay

    Directory of Open Access Journals (Sweden)

    Zhang PF

    2015-09-01

    Full Text Available Pengfei Zhang,1,* Yan Bao,1,* Mohamed Shehata Draz,2,3,* Huiqi Lu,1 Chang Liu,1 Huanxing Han11Center for Translational Medicine, Changzheng Hospital, Second Military Medical University, Shanghai, People’s Republic of China; 2Zhejiang-California International Nanosystems Institute, Zhejiang University, Hangzhou, Zhejiang, People’s Republic of China; 3Faculty of Science, Tanta University, Tanta, Egypt*These authors contributed equally to this workAbstract: Convenient and rapid immunofiltration assays (IFAs enable on-site “yes” or “no” determination of disease markers. However, traditional IFAs are commonly qualitative or semi-quantitative and are very limited for the efficient testing of samples in field diagnostics. Here, we overcome these limitations by developing a quantum dots (QDs-based fluorescent IFA for the quantitative detection of C-reactive proteins (CRP. CRP, the well-known diagnostic marker for acute viral and bacterial infections, was used as a model analyte to demonstrate performance and sensitivity of our developed QDs-based IFA. QDs capped with both polyethylene glycol (PEG and glutathione were used as fluorescent labels for our IFAs. The presence of the surface PEG layer, which reduced the non-specific protein interactions, in conjunction with the inherent optical properties of QDs, resulted in lower background signal, increased sensitivity, and ability to detect CRP down to 0.79 mg/L with only 5 µL serum sample. In addition, the developed assay is simple, fast and can quantitatively detect CRP with a detection limit up to 200 mg/L. Clinical test results of our QD-based IFA are well correlated with the traditional latex enhance immune-agglutination aggregation. The proposed QD-based fluorescent IFA is very promising, and potentially will be adopted for multiplexed immunoassay and in field point-of-care test.Keywords: C-reactive proteins, point-of-care test, Glutathione capped QDs, PEGylation

  18. Predicting cellulose solvating capabilities of acid-base conjugate ionic liquids.

    Science.gov (United States)

    Parviainen, Arno; King, Alistair W T; Mutikainen, Ilpo; Hummel, Michael; Selg, Christoph; Hauru, Lauri K J; Sixta, Herbert; Kilpeläinen, Ilkka

    2013-11-01

    Different acid-base conjugates were made by combining a range of bases and superbases with acetic and propionic acid. Only the combinations that contained superbases were capable of dissolving cellulose. Proton affinities were calculated for the bases. A range, within which cellulose dissolution occurred, when combined with acetic or propionic acid, was defined for further use. This was above a proton affinity value of about 240 kcal mol(-1) at the MP2/6-311+G(d,p)//MP2/ 6-311+G(d,p) ab initio level. Understanding dissolution allowed us to determine that cation acidity contributed considerably to the ability of ionic liquids to dissolve cellulose and not just the basicity of the anion. By XRD analyses of suitable crystals, hydrogen bonding interactions between anion and cation were found to be the dominant interactions in the crystalline state. From determination of viscosities of these conjugates over a temperature range, certain structures were found to have as low a viscosity as 1-ethyl-3-methylimidazolium acetate, which was reflected in their high rate of cellulose dissolution but not necessarily the quantitative solubility of cellulose in those ionic liquids. 1,5-Diazabicyclo[4.3.0]non-5-enium propionate, which is one of the best structures for cellulose dissolution, was then distilled using laboratory equipment to demonstrate its recyclability.

  19. Quantitative Safety: Linking Proof-Based Verification with Model Checking for Probabilistic Systems

    CERN Document Server

    Ndukwu, Ukachukwu

    2009-01-01

    This paper presents a novel approach for augmenting proof-based verification with performance-style analysis of the kind employed in state-of-the-art model checking tools for probabilistic systems. Quantitative safety properties usually specified as probabilistic system invariants and modeled in proof-based environments are evaluated using bounded model checking techniques. Our specific contributions include the statement of a theorem that is central to model checking safety properties of proof-based systems, the establishment of a procedure; and its full implementation in a prototype system (YAGA) which readily transforms a probabilistic model specified in a proof-based environment to its equivalent verifiable PRISM model equipped with reward structures. The reward structures capture the exact interpretation of the probabilistic invariants and can reveal succinct information about the model during experimental investigations. Finally, we demonstrate the novelty of the technique on a probabilistic library cas...

  20. Fast quantitative analysis of boric acid by gas chromatography-mass spectrometry coupled with a simple and selective derivatization reaction using triethanolamine.

    Science.gov (United States)

    Zeng, Li-Min; Wang, Hao-Yang; Guo, Yin-Long

    2010-03-01

    A fast, selective, and sensitive GC-MS method has been developed and validated for the determination of boric acid in the drinking water by derivatization with triethanolamine. This analytic strategy successfully converts the inorganic, nonvolatile boric acid B(OH)(3) present in the drinking water to a volatile triethanolamine borate B(OCH(2)CH(2))(3)N in a quantitative manner, which facilitates the GC measurement. The SIM mode was applied in the analysis and showed high accuracy, specificity, and reproducibility, as well as reducing the matrix effect effectively. The calibration curve was obtained from 0.01 microg/mL to 10.0 microg/mL with a satisfactory correlation coefficient of 0.9988. The limit of detection for boric acid was 0.04 microg/L. Then the method was applied for detection of the amount of boric acid in bottled drinking water and the results are in accordance with the reported concentration value of boric acid. This study offers a perspective into the utility of GC-MS as an alternate quantitative tool for detection of B(OH)(3), even for detection of boron in various other samples by digesting the boron compounds to boric acid. Copyright 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  1. Effect of foliar application of salicylic acid and thiamine on quantitative and qualitative characteristics of gerbera (Gerbera jamesonii L. cv. Pink Elegance

    Directory of Open Access Journals (Sweden)

    M. Mansouri

    2015-11-01

    Full Text Available Gerbera is one of the most important cut flowers in the world which is produced extensively in many commercial greenhouses. Nowadays, increasing yield and quality are production necessities. The aim of this research was evaluation of foliar application effects of salicylic acid and thiamine on quantitative and qualitative characteristics of gerbera flower. The experiment was conducted in a completely randomized design with four replications, in pots in greenhouse. Treatments included tap water (control, salicylic acid concentration (75 and 150 µM and thiamine concentration (250 and 500 µM. Foliar application was performed in two stages, with an interval of two weeks. Results showed that the treatments had significant effect on quantitative and qualitative characteristics of gerbera flower. The largest flower diameter, the shortest growing period and the highest number of flowers was related to 75 µM salicylic acid treatment. The largest diameter of the stem was observed in 150 µM salicylic acid treatment. In this experiment, 500 µM thiamine treatment produced the greatest height of flowering stem and had the highest chlorophyll index. Therefore, it seems that salicylic acid and thiamine could increase production efficiency and improve gerbera flower quality, and in this respect, the best treatment was 75 µM salicylic acid.

  2. A review on mass spectrometry-based quantitative proteomics: Targeted and data independent acquisition.

    Science.gov (United States)

    Vidova, Veronika; Spacil, Zdenek

    2017-04-29

    Mass spectrometry (MS) based proteomics have achieved a near-complete proteome coverage in humans and in several other organisms, producing a wealth of information stored in databases and bioinformatics resources. Recent implementation of selected/multiple reaction monitoring (SRM/MRM) technology in targeted proteomics introduced the possibility of quantitatively follow-up specific protein targets in a hypothesis-driven experiment. In contrast to immunoaffinity-based workflows typically used in biological and clinical research for protein quantification, SRM/MRM is characterized by high selectivity, large capacity for multiplexing (approx. 200 proteins per analysis) and rapid, cost-effective transition from assay development to deployment. The concept of SRM/MRM utilizes triple quadrupole (QqQ) mass analyzer to provide inherent reproducibility, unparalleled sensitivity and selectivity to efficiently differentiate isoforms, post-translational modifications and mutated forms of proteins. SRM-like targeted acquisitions such as parallel reaction monitoring (PRM) are pioneered on high resolution/accurate mass (HR/AM) platforms based on the quadrupole-orbitrap (Q-orbitrap) mass spectrometer. The expansion of HR/AM also caused development in data independent acquisition (DIA). This review presents a step-by-step tutorial on development of SRM/MRM protein assay intended for researchers without prior experience in proteomics. We discus practical aspects of SRM-based quantitative proteomics workflow, summarize milestones in basic biological and medical research as well as recent trends and emerging techniques. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. A Statistical Framework for Protein Quantitation in Bottom-Up MS-Based Proteomics

    Energy Technology Data Exchange (ETDEWEB)

    Karpievitch, Yuliya; Stanley, Jeffrey R.; Taverner, Thomas; Huang, Jianhua; Adkins, Joshua N.; Ansong, Charles; Heffron, Fred; Metz, Thomas O.; Qian, Weijun; Yoon, Hyunjin; Smith, Richard D.; Dabney, Alan R.

    2009-08-15

    Motivation: Quantitative mass spectrometry-based proteomics requires protein-level estimates and associated confidence measures. Challenges include the presence of low quality or incorrectly identified peptides and informative missingness. Furthermore, models are required for rolling peptide-level information up to the protein level. Results: We present a statistical model that carefully accounts for informative missingness in peak intensities and allows unbiased, model-based, protein-level estimation and inference. The model is applicable to both label-based and label-free quantitation experiments. We also provide automated, model-based, algorithms for filtering of proteins and peptides as well as imputation of missing values. Two LC/MS datasets are used to illustrate the methods. In simulation studies, our methods are shown to achieve substantially more discoveries than standard alternatives. Availability: The software has been made available in the opensource proteomics platform DAnTE (http://omics.pnl.gov/software/). Contact: adabney@stat.tamu.edu Supplementary information: Supplementary data are available at Bioinformatics online.

  4. Quantitative Analysis of Single and Mix Food Antiseptics Basing on SERS Spectra with PLSR Method

    Science.gov (United States)

    Hou, Mengjing; Huang, Yu; Ma, Lingwei; Zhang, Zhengjun

    2016-06-01

    Usage and dosage of food antiseptics are very concerned due to their decisive influence in food safety. Surface-enhanced Raman scattering (SERS) effect was employed in this research to realize trace potassium sorbate (PS) and sodium benzoate (SB) detection. HfO2 ultrathin film-coated Ag NR array was fabricated as SERS substrate. Protected by HfO2 film, the SERS substrate possesses good acid resistance, which enables it to be applicable in acidic environment where PS and SB work. Regression relationship between SERS spectra of 0.3~10 mg/L PS solution and their concentration was calibrated by partial least squares regression (PLSR) method, and the concentration prediction performance was quite satisfactory. Furthermore, mixture solution of PS and SB was also quantitatively analyzed by PLSR method. Spectrum data of characteristic peak sections corresponding to PS and SB was used to establish the regression models of these two solutes, respectively, and their concentrations were determined accurately despite their characteristic peak sections overlapping. It is possible that the unique modeling process of PLSR method prevented the overlapped Raman signal from reducing the model accuracy.

  5. Ionic liquid supported acid/base-catalyzed production of biodiesel.

    Science.gov (United States)

    Lapis, Alexandre A M; de Oliveira, Luciane F; Neto, Brenno A D; Dupont, Jairton

    2008-01-01

    The transesterification (alcoholysis) reaction was successfully applied to synthesize biodiesel from vegetable oils using imidazolium-based ionic liquids under multiphase acidic and basic conditions. Under basic conditions, the combination of the ionic liquid 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMINTf2), alcohols, and K2CO3 (40 mol %) results in the production of biodiesel from soybean oil in high yields (>98%) and purity. H2SO4 immobilized in BMINTf2 efficiently promotes the transesterification reaction of soybean oil and various primary and secondary alcohols. In this multiphase process the acid is almost completely retained in the ionic liquid phase, while the biodiesel forms a separate phase. The recovered ionic liquid containing the acid could be reused at least six times without any significant loss in the biodiesel yield or selectivity. In both catalytic processes (acid and base), the reactions proceed as typical multiphasic systems in which the formed biodiesel accumulates as the upper phase and the glycerol by-product is selectively captured by the alcohol-ionic liquid-acid/base phase. Classical ionic liquids such as 1-n-butyl-3-methylimidazolium tetrafluoroborate and hexafluorophosphate are not stable under these acidic or basic conditions and decompose.

  6. Quantitative determination of fatty acids in cell membrane of Corynebacterium glutamicum during glutamic acid production by GC-MS%GC-MS定量检测谷氨酸发酵产酸期细胞膜脂肪酸

    Institute of Scientific and Technical Information of China (English)

    康茜; 赵策; 庄英萍; 刘玉伟; 杭海峰; 郭美锦; 储炬; 张嗣良

    2012-01-01

    The fatty acids in cell membrane of Corynebacterium gluta micum during glutamic acid production were quantitatively determined by GC-MS(SIM). The results showed that myristic acid, palmitoleic acid, palmitic acid, oleic acid and stearic acid were the main fatty acids in cell membrane of C. glutamicum. Among the 5 main fatty acids, the content of palmitic acid was highest, whereas the content of palmitoleic acid was lowest. Additionally, the ratio of saturated fatty acids to unsaturated fatty acids decreased after the biosyhthesis of glutamic acid initiated. It indicated that there might be a close relationship between the secretion of glutamic acid and the ratio of saturated fatty acids to unsaturated ones.%采用气相色谱质谱连用法(GC-MS)分析了谷氨酸棒状杆菌的细胞膜中脂肪酸的组分,并用选择离子检测方式(SIM)测定产酸期前后细胞膜脂肪酸含量的变化.结果表明:谷氨酸棒状杆菌细胞膜主要含有肉豆蔻酸、棕榈油酸、棕榈酸、硬脂酸和油酸等5种脂肪酸,其中棕榈酸含量最高,棕榈油酸含量最低;另外,在谷氨酸发酵过程中,随着产酸的启动,细胞膜中饱和脂肪酸与不饱和脂肪酸比率呈下降趋势,说明细胞膜中饱和脂肪酸与不饱和脂肪酸的比率与谷氨酸的分泌可能存在一定的关联性.

  7. Multicomponent quantitative spectroscopic analysis without reference substances based on ICA modelling.

    Science.gov (United States)

    Monakhova, Yulia B; Mushtakova, Svetlana P

    2017-05-01

    A fast and reliable spectroscopic method for multicomponent quantitative analysis of targeted compounds with overlapping signals in complex mixtures has been established. The innovative analytical approach is based on the preliminary chemometric extraction of qualitative and quantitative information from UV-vis and IR spectral profiles of a calibration system using independent component analysis (ICA). Using this quantitative model and ICA resolution results of spectral profiling of "unknown" model mixtures, the absolute analyte concentrations in multicomponent mixtures and authentic samples were then calculated without reference solutions. Good recoveries generally between 95% and 105% were obtained. The method can be applied to any spectroscopic data that obey the Beer-Lambert-Bouguer law. The proposed method was tested on analysis of vitamins and caffeine in energy drinks and aromatic hydrocarbons in motor fuel with 10% error. The results demonstrated that the proposed method is a promising tool for rapid simultaneous multicomponent analysis in the case of spectral overlap and the absence/inaccessibility of reference materials.

  8. Quantitative autoradiography using a radioimager based on a multiwire proportional chamber

    Science.gov (United States)

    Petegnief, Yolande; Petiet, Anne; Peker, Muammer Can; Bonnin, François; Meulemans, Alain; LeGuludec, Dominique

    1998-12-01

    Determination of the biodistribution of radiopharmaceuticals is an important issue for the evaluation of their performance in diagnosis and therapy. In this study, we evaluated a digital radioimager (RI) based on a multiwire proportional chamber for quantitative autoradiography (AR). The RI allows direct detection of electronic emissions of gamma emitters. Its qualitative and quantitative performances were tested on Tc and In labelled sections and compared with conventional film AR. Linearity of count rate versus activity was verified over a range of activity. As compared with film AR, a substantial improvement of the detection limit was obtained even for acquisition periods up to 20 times less than film exposure times. We provided the basis for quantitative analysis with tissue equivalent paste standards: the Tc and In RI counting efficiencies were respectively 1.19% and 2.35%. We illustrated the respective values of RI and film AR in two rat studies: Tc-DMSA in kidney and dual-isotope Tc-MIBI and In-antimyosin in heart. Calculated activity concentrations on sections of rat organs confirmed good correlation to gamma counting (deviation less than 12%). We suggest RI as a convenient technique for fast localization of single or dual-isotope tracers and determination of activity distribution.

  9. Quantitative autoradiography using a radioimager based on a multiwire proportional chamber

    Energy Technology Data Exchange (ETDEWEB)

    Petegnief, Y.; Peker, M.C.; Meulemans, A.; Le Guludec, D. [Service de Medecine Nucleaire et de Biophysique, Hopital Bichat-Claude Bernard, 46 rue H Huchard, F-75877 Paris Cedex 18 (France); Petiet, A.; Bonnin, F. [Laboratoire de Biophysique, Universite Paris 7, BP 416, F-75780 Paris (France)

    1998-12-01

    Determination of the biodistribution of radiopharmaceuticals is an important issue for the evaluation of their performance in diagnosis and therapy. In this study, we evaluated a digital radioimager (RI) based on a multiwire proportional chamber for quantitative autoradiography (AR). The RI allows direct detection of electronic emissions of gamma emitters. Its qualitative and quantitative performances were tested on {sup 99m}Tc and {sup 111}In labelled sections and compared with conventional film AR. Linearity of count rate versus activity was verified over a 10{sup 4} range of activity. As compared with film AR, a substantial improvement of the detection limit was obtained even for acquisition periods up to 20 times less than film exposure times. We provided the basis for quantitative analysis with tissue equivalent paste standards: the {sup 99m}Tc and {sup 111}In RI counting efficiencies were respectively 1.19% and 2.35%. We illustrated the respective values of RI and film AR in two rat studies: {sup 99m}Tc-DMSA in kidney and dual-isotope {sup 99m}Tc-MIBI and {sup 111}In-antimyosin in heart. Calculated activity concentrations on sections of rat organs confirmed good correlation to gamma counting (deviation less than 12%). We suggest RI as a convenient technique for fast localization of single or dual-isotope tracers and determination of activity distribution. (author)

  10. 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.

  11. Deoxyribonucleic acid base compositions of dermatophytes.

    Science.gov (United States)

    Davison, F D; Mackenzie, D W; Owen, R J

    1980-06-01

    DNA was extracted and purified from 55 dermatophyte isolates representing 34 species of Trichophyton, Microsporum and Epidermophyton. The base compositions of the chromosomal DNA were determined by CsCl density gradient centrifugation and were found to be in the narrow range of 48.7 to 50.3 mol % G + C. A satellite DNA component assumed to be of mitochondrial origin was present in most strains, with a G + C content ranging from 14.7 to 30.8 mol % G + C. Heterogeneity in microscopic and colonial characteristics was not reflected in differences in the mean G + C content of the chromosomal DNAs. Strains varied in the G + C contents of satelite DNA, but these did not correlate with traditional species concepts.

  12. Quantitative assessment of fibrinogen cross-linking by epsilon aminocaproic acid in patients with end-stage liver disease.

    Science.gov (United States)

    Quach, Thien; Tippens, Melissa; Szlam, Fania; Van Dyke, Rebecca; Levy, Jerrold H; Csete, Marie

    2004-01-01

    Analysis of the effectiveness of antifibrinolytic therapy for liver transplant recipients is hampered by lack of quantitative assays for assessing drug effects. We adapted chemical engineering tools used in polymerization studies to quantify fibrinogen cross-linking by plasma from liver transplant patients obtained before and after epsilon aminocaproic acid (EACA) therapy. A target fluorescein isothiocyanate-fibrinogen (FITC-fibrinogen) molecule was constructed; it fluoresces in a quantifiable pattern when in solution, and undergoes cross-linking in the presence of plasmin inhibitors. Cross-linking quenches the fluorescent signal, and the quenching is a quantifiable endpoint. Thus fluorescence from this reporter molecule can be used to assess functional improvement in fibrinogen cross-linking as a result of antifibrinolytic therapies, and it is sensitive to picomolar amounts of plasmin inhibitors and activators. Cross-linking of FITC-fibrinogen by patient plasma, before and after EACA therapy, was assessed using fluorescence spectrometry. Fluorescence patterns from FITC-fibrinogen indicated no significant cross-linking of the target fibrinogen as a consequence of EACA in posttreatment plasma. When the fibrinogen-FITC target was assayed without plasma in the presence of EACA at concentrations that bracket therapeutic levels (100 and 400 microg/ml), significant fluorescence quenching (target FITC-fibrinogen cross-linking) was achieved. These results suggest that fibrinogen-FITC fluorescence is sensitive enough to detect EACA activity in clinically relevant ranges, but that EACA given in usual doses is insufficient to promote fibrinogen cross-linking in patients with end-stage liver disease.

  13. Quantitative Metabolomic Analysis of Urinary Citrulline and Calcitroic Acid in Mice after Exposure to Various Types of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Maryam Goudarzi

    2016-05-01

    Full Text Available With the safety of existing nuclear power plants being brought into question after the Fukushima disaster and the increased level of concern over terrorism-sponsored use of improvised nuclear devices, it is more crucial to develop well-defined radiation injury markers in easily accessible biofluids to help emergency-responders with injury assessment during patient triage. Here, we focused on utilizing ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS to identify and quantitate the unique changes in the urinary excretion of two metabolite markers, calcitroic acid and citrulline, in mice induced by different forms of irradiation; X-ray irradiation at a low dose rate (LDR of 3.0 mGy/min and a high dose rate (HDR of 1.1 Gy/min, and internal exposure to Cesium-137 (137Cs and Strontium-90 (90Sr. The multiple reaction monitoring analysis showed that, while exposure to 137Cs and 90Sr induced a statistically significant and persistent decrease, similar doses of X-ray beam at the HDR had the opposite effect, and the LDR had no effect on the urinary levels of these two metabolites. This suggests that the source of exposure and the dose rate strongly modulate the in vivo metabolomic injury responses, which may have utility in clinical biodosimetry assays for the assessment of exposure in an affected population. This study complements our previous investigations into the metabolomic profile of urine from mice internally exposed to 90Sr and 137Cs and to X-ray beam radiation.

  14. Quantitative determination of five hydroxy acids, precursors of relevant wine aroma compounds in wine and other alcoholic beverages.

    Science.gov (United States)

    Gracia-Moreno, Elisa; Lopez, Ricardo; Ferreira, Vicente

    2015-10-01

    A method for the quantitative determination of 2-hydroxy-2-methylbutanoic (2OH2MB), 2-hydroxy-3-methylbutanoic (2OH3MB), 3-hydroxy-3-methylbutanoic (3OH3MB), 2-hydroxy-4-methylpentanoic (2OH4MP) and 3-hydroxybutanoic (3OHB) acids has been optimized, validated and applied to a set of wines and other alcoholic beverages. The analytes were preconcentrated in a solid phase extraction cartridge and derivatized with 2,3,4,5,6-pentafluorobenzyl bromide at room temperature for 30 min, followed by GC-MS analysis. Detection limits were between 0.5 and 29 μg L(-1), and linearity was maintained up to 3 or 12 mg L(-1), depending on the analyte. Recovery values were between 85 and 106 %, and reproducibility was better than 12 % RSD in most cases. The first specific study of these analytes in wine and other alcoholic beverages is herein reported. Concentrations ranged from the method detection limits to 7820, 519, 8510, 3470 and 2500 μg L(-1) for 2OH2MB, 2OH3MB, 3OH3MB, 2OH4MP and 3OHB, respectively, which may have relevant sensory effects. These products were not found in distillates (except 3OHB) but were all present in beer. 2OH2MB, 3OH3MB and 3OHB were found in unfermented grape derivatives. Sherry wines had the highest levels of all except for 3OHB.

  15. A novel approach for evaluating the performance of real time quantitative loop-mediated isothermal amplification-based methods

    Directory of Open Access Journals (Sweden)

    Gavin J. Nixon

    2014-12-01

    Full Text Available Molecular diagnostic measurements are currently underpinned by the polymerase chain reaction (PCR. There are also a number of alternative nucleic acid amplification technologies, which unlike PCR, work at a single temperature. These ‘isothermal’ methods, reportedly offer potential advantages over PCR such as simplicity, speed and resistance to inhibitors and could also be used for quantitative molecular analysis. However there are currently limited mechanisms to evaluate their quantitative performance, which would assist assay development and study comparisons. This study uses a sexually transmitted infection diagnostic model in combination with an adapted metric termed isothermal doubling time (IDT, akin to PCR efficiency, to compare quantitative PCR and quantitative loop-mediated isothermal amplification (qLAMP assays, and to quantify the impact of matrix interference. The performance metric described here facilitates the comparison of qLAMP assays that could assist assay development and validation activities.

  16. Synthesis and characterization of boric acid mediated metal-organic frameworks based on trimesic acid and terephthalic acid

    Science.gov (United States)

    Ozer, Demet; Köse, Dursun A.; Şahin, Onur; Oztas, Nursen Altuntas

    2017-08-01

    The new metal-organic framework materials based on boric acid reported herein. Sodium and boron containing metal-organic frameworks were synthesized by one-pot self-assembly reaction in the presence of trimesic acid and terephthalic acid in water/ethanol solution. Boric acid is a relatively cheap boron source and boric acid mediated metal-organic framework prepared mild conditions compared to the other boron source based metal-organic framework. The synthesized compounds were characterized by FT-IR, p-XRD, TGA/DTA, elemental analysis, 13C-MAS NMR, 11B-NMR and single crystal measurements. The molecular formulas of compounds were estimated as C18H33B2Na5O28 and C8H24B2Na2O17 according to the structural analysis. The obtained complexes were thermally stable. Surface properties of inorganic polymer complexes were investigated by BET analyses and hydrogen storage properties of compound were also calculated.

  17. Effect of animal and industrial trans fatty acids on HDL and LDL cholesterol levels in humans--a quantitative review.

    Directory of Open Access Journals (Sweden)

    Ingeborg A Brouwer

    Full Text Available BACKGROUND: Trans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower HDL cholesterol, raise LDL cholesterol, and increase the risk of coronary heart disease. The effects of conjugated linoleic acid and trans fatty acids from ruminant animals are less clear. We reviewed the literature, estimated the effects trans fatty acids from ruminant sources and of conjugated trans linoleic acid (CLA on blood lipoproteins, and compared these with industrial trans fatty acids. METHODOLOGY/PRINCIPAL FINDINGS: We searched Medline and scanned reference lists for intervention trials that reported effects of industrial trans fatty acids, ruminant trans fatty acids or conjugated linoleic acid on LDL and HDL cholesterol in humans. The 39 studies that met our criteria provided results of 29 treatments with industrial trans fatty acids, 6 with ruminant trans fatty acids and 17 with CLA. Control treatments differed between studies; to enable comparison between studies we recalculated for each study what the effect of trans fatty acids on lipoprotein would be if they isocalorically replaced cis mono unsaturated fatty acids. In linear regression analysis the plasma LDL to HDL cholesterol ratio increased by 0.055 (95%CI 0.044-0.066 for each % of dietary energy from industrial trans fatty acids replacing cis monounsaturated fatty acids The increase in the LDL to HDL ratio for each % of energy was 0.038 (95%CI 0.012-0.065 for ruminant trans fatty acids, and 0.043 (95% CI 0.012-0.074 for conjugated linoleic acid (p = 0.99 for difference between CLA and industrial trans fatty acids; p = 0.37 for ruminant versus industrial trans fatty acids. CONCLUSIONS/SIGNIFICANCE: Published data suggest that all fatty acids with a double bond in the trans configuration raise the ratio of plasma LDL to HDL cholesterol.

  18. Method and platform standardization in MRM-based quantitative plasma proteomics.

    Science.gov (United States)

    Percy, Andrew J; Chambers, Andrew G; Yang, Juncong; Jackson, Angela M; Domanski, Dominik; Burkhart, Julia; Sickmann, Albert; Borchers, Christoph H

    2013-12-16

    There exists a growing demand in the proteomics community to standardize experimental methods and liquid chromatography-mass spectrometry (LC/MS) platforms in order to enable the acquisition of more precise and accurate quantitative data. This necessity is heightened by the evolving trend of verifying and validating candidate disease biomarkers in complex biofluids, such as blood plasma, through targeted multiple reaction monitoring (MRM)-based approaches with stable isotope-labeled standards (SIS). Considering the lack of performance standards for quantitative plasma proteomics, we previously developed two reference kits to evaluate the MRM with SIS peptide approach using undepleted and non-enriched human plasma. The first kit tests the effectiveness of the LC/MRM-MS platform (kit #1), while the second evaluates the performance of an entire analytical workflow (kit #2). Here, these kits have been refined for practical use and then evaluated through intra- and inter-laboratory testing on 6 common LC/MS platforms. For an identical panel of 22 plasma proteins, similar concentrations were determined, regardless of the kit, instrument platform, and laboratory of analysis. These results demonstrate the value of the kit and reinforce the utility of standardized methods and protocols. The proteomics community needs standardized experimental protocols and quality control methods in order to improve the reproducibility of MS-based quantitative data. This need is heightened by the evolving trend for MRM-based validation of proposed disease biomarkers in complex biofluids such as blood plasma. We have developed two kits to assist in the inter- and intra-laboratory quality control of MRM experiments: the first kit tests the effectiveness of the LC/MRM-MS platform (kit #1), while the second evaluates the performance of an entire analytical workflow (kit #2). In this paper, we report the use of these kits in intra- and inter-laboratory testing on 6 common LC/MS platforms. This

  19. Solution identification and quantitative analysis of fiber-capacitive drop analyzer based on multivariate statistical methods

    Science.gov (United States)

    Chen, Zhe; Qiu, Zurong; Huo, Xinming; Fan, Yuming; Li, Xinghua

    2017-03-01

    A fiber-capacitive drop analyzer is an instrument which monitors a growing droplet to produce a capacitive opto-tensiotrace (COT). Each COT is an integration of fiber light intensity signals and capacitance signals and can reflect the unique physicochemical property of a liquid. In this study, we propose a solution analytical and concentration quantitative method based on multivariate statistical methods. Eight characteristic values are extracted from each COT. A series of COT characteristic values of training solutions at different concentrations compose a data library of this kind of solution. A two-stage linear discriminant analysis is applied to analyze different solution libraries and establish discriminant functions. Test solutions can be discriminated by these functions. After determining the variety of test solutions, Spearman correlation test and principal components analysis are used to filter and reduce dimensions of eight characteristic values, producing a new representative parameter. A cubic spline interpolation function is built between the parameters and concentrations, based on which we can calculate the concentration of the test solution. Methanol, ethanol, n-propanol, and saline solutions are taken as experimental subjects in this paper. For each solution, nine or ten different concentrations are chosen to be the standard library, and the other two concentrations compose the test group. By using the methods mentioned above, all eight test solutions are correctly identified and the average relative error of quantitative analysis is 1.11%. The method proposed is feasible which enlarges the applicable scope of recognizing liquids based on the COT and improves the concentration quantitative precision, as well.

  20. Accurate Quantitative Sensing of Intracellular pH based on Self-ratiometric Upconversion Luminescent Nanoprobe

    Science.gov (United States)

    Li, Cuixia; Zuo, Jing; Zhang, Li; Chang, Yulei; Zhang, Youlin; Tu, Langping; Liu, Xiaomin; Xue, Bin; Li, Qiqing; Zhao, Huiying; Zhang, Hong; Kong, Xianggui

    2016-12-01

    Accurate quantitation of intracellular pH (pHi) is of great importance in revealing the cellular activities and early warning of diseases. A series of fluorescence-based nano-bioprobes composed of different nanoparticles or/and dye pairs have already been developed for pHi sensing. Till now, biological auto-fluorescence background upon UV-Vis excitation and severe photo-bleaching of dyes are the two main factors impeding the accurate quantitative detection of pHi. Herein, we have developed a self-ratiometric luminescence nanoprobe based on förster resonant energy transfer (FRET) for probing pHi, in which pH-sensitive fluorescein isothiocyanate (FITC) and upconversion nanoparticles (UCNPs) were served as energy acceptor and donor, respectively. Under 980 nm excitation, upconversion emission bands at 475 nm and 645 nm of NaYF4:Yb3+, Tm3+ UCNPs were used as pHi response and self-ratiometric reference signal, respectively. This direct quantitative sensing approach has circumvented the traditional software-based subsequent processing of images which may lead to relatively large uncertainty of the results. Due to efficient FRET and fluorescence background free, a highly-sensitive and accurate sensing has been achieved, featured by 3.56 per unit change in pHi value 3.0–7.0 with deviation less than 0.43. This approach shall facilitate the researches in pHi related areas and development of the intracellular drug delivery systems.

  1. Temporal Data Set Reduction Based on D-Optimality for Quantitative FLIM-FRET Imaging.

    Science.gov (United States)

    Omer, Travis; Intes, Xavier; Hahn, Juergen

    2015-01-01

    Fluorescence lifetime imaging (FLIM) when paired with Förster resonance energy transfer (FLIM-FRET) enables the monitoring of nanoscale interactions in living biological samples. FLIM-FRET model-based estimation methods allow the quantitative retrieval of parameters such as the quenched (interacting) and unquenched (non-interacting) fractional populations of the donor fluorophore and/or the distance of the interactions. The quantitative accuracy of such model-based approaches is dependent on multiple factors such as signal-to-noise ratio and number of temporal points acquired when sampling the fluorescence decays. For high-throughput or in vivo applications of FLIM-FRET, it is desirable to acquire a limited number of temporal points for fast acquisition times. Yet, it is critical to acquire temporal data sets with sufficient information content to allow for accurate FLIM-FRET parameter estimation. Herein, an optimal experimental design approach based upon sensitivity analysis is presented in order to identify the time points that provide the best quantitative estimates of the parameters for a determined number of temporal sampling points. More specifically, the D-optimality criterion is employed to identify, within a sparse temporal data set, the set of time points leading to optimal estimations of the quenched fractional population of the donor fluorophore. Overall, a reduced set of 10 time points (compared to a typical complete set of 90 time points) was identified to have minimal impact on parameter estimation accuracy (≈5%), with in silico and in vivo experiment validations. This reduction of the number of needed time points by almost an order of magnitude allows the use of FLIM-FRET for certain high-throughput applications which would be infeasible if the entire number of time sampling points were used.

  2. Predicting The Service Life Of Concrete Bridges Based On Quantitative Research

    Directory of Open Access Journals (Sweden)

    Gode Kristaps

    2014-10-01

    Full Text Available A new method is proposed that will help predict the remaining service life of concrete bridges based on quantitative deterioration research. It is suggested that for a given degree of damage (stage and corresponding environmental and bridge design factors, there is only one time value. In that way it is possible to calculate the deterioration rate for given environmental and bridge design factors shared by many different bridges. The method can be used to calculate the key parameters for corrosion deterioration, thereby enabling the prediction of the remaining service life of a bridge using DuraCrete deterioration models

  3. Quantitative comparison between microfluidic and microtiter plate formats for cell-based assays.

    Science.gov (United States)

    Yin, Huabing; Pattrick, Nicola; Zhang, Xunli; Klauke, Norbert; Cordingley, Hayley C; Haswell, Steven J; Cooper, Jonathan M

    2008-01-01

    In this paper, we compare a quantitative cell-based assay measuring the intracellular Ca2+ response to the agonist uridine 5'-triphosphate in Chinese hamster ovary cells, in both microfluidic and microtiter formats. The study demonstrates that, under appropriate hydrodynamic conditions, there is an excellent agreement between traditional well-plate assays and those obtained on-chip for both suspended immobilized cells and cultured adherent cells. We also demonstrate that the on-chip assay, using adherent cells, provides the possibility of faster screening protocols with the potential for resolving subcellular information about local Ca2+ flux.

  4. A method for quantitative analysis of aquatic humic substances in clear water based on carbon concentration.

    Science.gov (United States)

    Tsuda, Kumiko; Takata, Akihiro; Shirai, Hidekado; Kozaki, Katsutoshi; Fujitake, Nobuhide

    2012-01-01

    Aquatic humic substances (AHSs) are major constituents of dissolved organic matter (DOM) in freshwater, where they perform a number of important ecological and geochemical functions, yet no method exists for quantifying all AHSs. We have developed a method for the quantitative analysis of AHSs based on their carbon concentration. Our approach includes: (1) the development of techniques for clear-water samples with low AHS concentrations, which normally complicate quantification; (2) avoiding carbon contamination in the laboratory; and (3) optimizing the AHS adsorption conditions.

  5. A quantitative application of the J-based configuration analysis method to a flexible small molecule.

    Science.gov (United States)

    Sharman, Gary J

    2007-04-01

    An example of the use of the J-based configuration analysis method to determine relative stereochemistry of a small molecule related to reboxetine is described. This study was complicated by the fact that the molecule did not exhibit J-couplings and NOEs consistent with a single conformation, but rather an ensemble average. A quantitative fitting procedure using predicted couplings and NOEs from all possible conformers was used. This gave a clear indication of the stereochemistry, and the populations of the conformers involved.

  6. An international collaborative family-based whole genome quantitative trait linkage scan for myopic refractive error

    DEFF Research Database (Denmark)

    Abbott, Diana; Li, Yi-Ju; Guggenheim, Jeremy A;

    2012-01-01

    To investigate quantitative trait loci linked to refractive error, we performed a genome-wide quantitative trait linkage analysis using single nucleotide polymorphism markers and family data from five international sites.......To investigate quantitative trait loci linked to refractive error, we performed a genome-wide quantitative trait linkage analysis using single nucleotide polymorphism markers and family data from five international sites....

  7. Ionic liquids based microwave-assisted extraction of lichen compounds with quantitative spectrophotodensitometry analysis.

    Science.gov (United States)

    Bonny, Sarah; Paquin, Ludovic; Carrié, Daniel; Boustie, Joël; Tomasi, Sophie

    2011-11-30

    Ionic liquids based extraction method has been applied to the effective extraction of norstictic acid, a common depsidone isolated from Pertusaria pseudocorallina, a crustose lichen. Five 1-alkyl-3-methylimidazolium ionic liquids (ILs) differing in composition of alkyl chain and anion were investigated for extraction efficiency. The extraction amount of norstictic acid was determined after recovery on HPTLC with a spectrophotodensitometer. The proposed approaches (IL-MAE and IL-heat extraction (IL-HE)) have been evaluated in comparison with usual solvents such as tetrahydrofuran in heat-reflux extraction and microwave-assisted extraction (MAE). The results indicated that both the characteristics of the alkyl chain and anion influenced the extraction of polyphenolic compounds. The sulfate-based ILs [C(1)mim][MSO(4)] and [C(2)mim][ESO(4)] presented the best extraction efficiency of norstictic acid. The reduction of the extraction times between HE and MAE (2 h-5 min) and a non-negligible ratio of norstictic acid in total extract (28%) supports the suitability of the proposed method. This approach was successfully applied to obtain additional compounds from other crustose lichens (Pertusaria amara and Ochrolechia parella).

  8. Contribute to quantitative identification of casting defects based on computer analysis of X-ray images

    Directory of Open Access Journals (Sweden)

    Z. Ignaszak

    2007-12-01

    Full Text Available The forecast of structure and properties of casting is based on results of computer simulation of physical processes which are carried out during the casting processes. For the effective using of simulation system it is necessary to validate mathematica-physical models describing process of casting formation and the creation of local discontinues, witch determinate the casting properties.In the paper the proposition for quantitative validation of VP system using solidification casting defects by information sources of II group (methods of NDT was introduced. It was named the VP/RT validation (virtual prototyping/radiographic testing validation. Nowadays identification of casting defects noticeable on X-ray images bases on comparison of X-ray image of casting with relates to the ASTM. The results of this comparison are often not conclusive because based on operator’s subjective assessment. In the paper the system of quantitative identification of iron casting defects on X-ray images and classification this defects to ASTM class is presented. The methods of pattern recognition and machine learning were applied.

  9. Research on Quantitative Models of Electric Vehicle Charging Stations Based on Principle of Energy Equivalence

    Directory of Open Access Journals (Sweden)

    Zhenpo Wang

    2013-01-01

    Full Text Available In order to adapt the matching and planning requirements of charging station in the electric vehicle (EV marketization application, with related layout theories of the gas stations, a location model of charging stations is established based on electricity consumption along the roads among cities. And a quantitative model of charging stations is presented based on the conversion of oil sales in a certain area. Both are combining the principle based on energy consuming equivalence substitution in process of replacing traditional vehicles with EVs. Defined data are adopted in the example analysis of two numerical case models and analyze the influence on charging station layout and quantity from the factors like the proportion of vehicle types and the EV energy consumption at the same time. The results show that the quantitative model of charging stations is reasonable and feasible. The number of EVs and the energy consumption of EVs bring more significant impact on the number of charging stations than that of vehicle type proportion, which provides a basis for decision making for charging stations construction layout in reality.

  10. Link-based quantitative methods to identify differentially coexpressed genes and gene Pairs

    Directory of Open Access Journals (Sweden)

    Ye Zhi-Qiang

    2011-08-01

    Full Text Available Abstract Background Differential coexpression analysis (DCEA is increasingly used for investigating the global transcriptional mechanisms underlying phenotypic changes. Current DCEA methods mostly adopt a gene connectivity-based strategy to estimate differential coexpression, which is characterized by comparing the numbers of gene neighbors in different coexpression networks. Although it simplifies the calculation, this strategy mixes up the identities of different coexpression neighbors of a gene, and fails to differentiate significant differential coexpression changes from those trivial ones. Especially, the correlation-reversal is easily missed although it probably indicates remarkable biological significance. Results We developed two link-based quantitative methods, DCp and DCe, to identify differentially coexpressed genes and gene pairs (links. Bearing the uniqueness of exploiting the quantitative coexpression change of each gene pair in the coexpression networks, both methods proved to be superior to currently popular methods in simulation studies. Re-mining of a publicly available type 2 diabetes (T2D expression dataset from the perspective of differential coexpression analysis led to additional discoveries than those from differential expression analysis. Conclusions This work pointed out the critical weakness of current popular DCEA methods, and proposed two link-based DCEA algorithms that will make contribution to the development of DCEA and help extend it to a broader spectrum.

  11. Brønsted acid sites based on penta-coordinated aluminum species

    Science.gov (United States)

    Wang, Zichun; Jiang, Yijiao; Lafon, Olivier; Trébosc, Julien; Duk Kim, Kyung; Stampfl, Catherine; Baiker, Alfons; Amoureux, Jean-Paul; Huang, Jun

    2016-12-01

    Zeolites and amorphous silica-alumina (ASA), which both provide Brønsted acid sites (BASs), are the most extensively used solid acid catalysts in the chemical industry. It is widely believed that BASs consist only of tetra-coordinated aluminum sites (AlIV) with bridging OH groups in zeolites or nearby silanols on ASA surfaces. Here we report the direct observation in ASA of a new type of BAS based on penta-coordinated aluminum species (AlV) by 27Al-{1H} dipolar-mediated correlation two-dimensional NMR experiments at high magnetic field under magic-angle spinning. Both BAS-AlIV and -AlV show a similar acidity to protonate probe molecular ammonia. The quantitative evaluation of 1H and 27Al sites demonstrates that BAS-AlV co-exists with BAS-AlIV rather than replaces it, which opens new avenues for strongly enhancing the acidity of these popular solid acids.

  12. Comparison of potentials between genotype-based selection and genotypic value-based selection of quantitative traits

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    According to the difference of selection criteria, methods of marker-assisted selection (MAS) of quantitative traits can be divided into genotype-based selection (GS) and genotypic value-based selection (GVS). By means of computer simulation, potentials of the two methods were compared. Results showed that the two methods had similar basic laws and their efficiencies were not significantly different except that GS behaved better in the case where the number of QTLs was large and QTL effects were equal. From the application point of view, combination of GS and GVS should be the development direction of MAS research in the future.

  13. Acid-base patterns in acute severe asthma.

    Science.gov (United States)

    Raimondi, Guillermo A; Gonzalez, Silvia; Zaltsman, Jorge; Menga, Guillermo; Adrogué, Horacio J

    2013-12-01

    Acid-base status in acute severe asthma (ASA) remains undefined; some studies report complete absence of metabolic acidosis, whereas others describe it as present in one fourth of patients or more. Conclusion discrepancies would therefore appear to derive from differences in assessment methodology. Only a systematic approach centering on patient clinical findings can correctly establish true acid-base disorder prevalence levels. This study examines acid-base patterns in ASA (314 patients), taking into account both natural history of disease and treatment, in patients free of other diseases altering acid-base status. Data were collected from patients admitted for ASA without prior history of chronic bronchitis, emphysema, kidney or liver disease, heart failure, uncontrolled diabetes mellitus or gastrointestinal illness. Informed consent was obtained for all patients, after study protocol approval by the Institutional Review Board. Arterial blood gases, plasma electrolytes, lactate levels, and FEV(1) were measured on arrival. Severe airway obstruction was found with FEV(1) values of 25.6 ± 10.0%, substantial hypoxemia (PaO(2) 66.1 ± 11.9 mmHg) and increased A-a O(2) gradient (39.3 ± 12.3 mmHg) breathing room air. While respiratory alkalosis occurred in patients with better preservation of FEV1, respiratory acidosis was observed with more severe airway obstruction, as was increased lactate in the majority of patients, independent of PaO(2) and PaCO(2) levels. Predominant acid-base patterns observed in ASA in this patient population included primary hypocapnia, or less frequently, primary hypercapnia. Lactic acidosis occurred in 11% of patients and presented consistently as a mixed acid-base disorder. These findings suggest lactic acidosis results from the combined effects of both ASA and medication-related sympathetic effects.

  14. Regulated acid-base transport in the collecting duct.

    Science.gov (United States)

    Wagner, Carsten A; Devuyst, Olivier; Bourgeois, Soline; Mohebbi, Nilufar

    2009-05-01

    The renal collecting system serves the fine-tuning of renal acid-base secretion. Acid-secretory type-A intercalated cells secrete protons via a luminally expressed V-type H(+)-ATPase and generate new bicarbonate released by basolateral chloride/bicarbonate exchangers including the AE1 anion exchanger. Efficient proton secretion depends both on the presence of titratable acids (mainly phosphate) and the concomitant secretion of ammonia being titrated to ammonium. Collecting duct ammonium excretion requires the Rhesus protein RhCG as indicated by recent KO studies. Urinary acid secretion by type-A intercalated cells is strongly regulated by various factors among them acid-base status, angiotensin II and aldosterone, and the Calcium-sensing receptor. Moreover, urinary acidification by H(+)-ATPases is modulated indirectly by the activity of the epithelial sodium channel ENaC. Bicarbonate secretion is achieved by non-type-A intercalated cells characterized by the luminal expression of the chloride/bicarbonate exchanger pendrin. Pendrin activity is driven by H(+)-ATPases and may serve both bicarbonate excretion and chloride reabsorption. The activity and expression of pendrin is regulated by different factors including acid-base status, chloride delivery, and angiotensin II and may play a role in NaCl retention and blood pressure regulation. Finally, the relative abundance of type-A and non-type-A intercalated cells may be tightly regulated. Dysregulation of intercalated cell function or abundance causes various syndromes of distal renal tubular acidosis underlining the importance of these processes for acid-base homeostasis.

  15. Genetic algorithm based image binarization approach and its quantitative evaluation via pooling

    Science.gov (United States)

    Hu, Huijun; Liu, Ya; Liu, Maofu

    2015-12-01

    The binarized image is very critical to image visual feature extraction, especially shape feature, and the image binarization approaches have been attracted more attentions in the past decades. In this paper, the genetic algorithm is applied to optimizing the binarization threshold of the strip steel defect image. In order to evaluate our genetic algorithm based image binarization approach in terms of quantity, we propose the novel pooling based evaluation metric, motivated by information retrieval community, to avoid the lack of ground-truth binary image. Experimental results show that our genetic algorithm based binarization approach is effective and efficiency in the strip steel defect images and our quantitative evaluation metric on image binarization via pooling is also feasible and practical.

  16. Fine mapping quantitative trait loci under selective phenotyping strategies based on linkage and linkage disequilibrium criteria

    DEFF Research Database (Denmark)

    Ansari-Mahyari, S; Berg, P; Lund, M S

    2009-01-01

    In fine mapping of a large-scale experimental population where collection of phenotypes are very expensive, difficult to record or time-demanding, selective phenotyping could be used to phenotype the most informative individuals. Linkage analyses based sampling criteria (LAC) and linkage...... disequilibrium-based sampling criteria (LDC) for selecting individuals to phenotype are compared to random phenotyping in a quantitative trait loci (QTL) verification experiment using stochastic simulation. Several strategies based on LAC and LDC for selecting the most informative 30%, 40% or 50% of individuals...... for phenotyping to extract maximum power and precision in a QTL fine mapping experiment were developed and assessed. Linkage analyses for the mapping was performed for individuals sampled on LAC within families and combined linkage disequilibrium and linkage analyses was performed for individuals sampled across...

  17. Quantitative structure-retardation factor relationship of protein amino acids in different solvent mixtures for normal-phase thin-layer chromatography.

    Science.gov (United States)

    Yousefinejad, Saeed; Honarasa, Fatemeh; Saeed, Negar

    2015-05-01

    A quantitative predictive/descriptive model was proposed for the retardation factors of protein amino acids in normal-phase thin-layer chromatography. The experimental retardation factors of 126 chromatographic mixtures (21 protein amino acids in different mobile phases) were used as the independent variable. The matrix of dependent variables of the model was built using structural descriptors of amino acids and empirical parameters of solvents of the applied mobile phases. After variable selection, a five-parametr model was proposed for the retardation factor of amino acids, which covered about 84 and 77% variance of data in training and cross-validation, respectively. The correlation coefficient of the external test set was 0.80, which shows the prediction potential of proposed model as well as its good applicability domain that was checked using a standardized residual-leverage plot. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Troger's base molecular scaffolds in dicarboxylic acid recognition.

    Science.gov (United States)

    Goswami, S; Ghosh, K; Dasgupta, S

    2000-04-07

    Artificial receptors (1-5) have been designed and synthesized from simple precursors. The chain length selectivity studies of dicarboxylic acids within the cavities of new fluorescent Troger's base molecular frameworks (1-3) have been carried out with a critical examination of their role of rigidity as well as flexibility in selective binding in comparison to receptor 5. The chiral resolution of the racemic Troger's base receptors (1 and 2) by chiral recognition with (+)- camphoric acid using hydrogen-bonding interactions has been studied.

  19. Carbon Dot Based Sensing of Dopamine and Ascorbic Acid

    Directory of Open Access Journals (Sweden)

    Upama Baruah

    2014-01-01

    Full Text Available We demonstrate carbon dot based sensor of catecholamine, namely, dopamine and ascorbic acid. Carbon dots (CDs were prepared from a green source: commercially available Assam tea. The carbon dots prepared from tea had particle sizes of ∼0.8 nm and are fluorescent. Fluorescence of the carbon dots was found to be quenched in the presence of dopamine and ascorbic acid with greater sensitivity for dopamine. The minimum detectable limits were determined to be 33 μM and 98 μM for dopamine and ascorbic acid, respectively. The quenching constants determined from Stern-Volmer plot were determined to be 5 × 10−4 and 1 × 10−4 for dopamine and ascorbic acid, respectively. A probable mechanism of quenching has been discussed in the paper.

  20. Relativistic effects on acidities and basicities of Brønsted acids and bases containing gold.

    Science.gov (United States)

    Koppel, Ilmar A; Burk, Peeter; Kasemets, Kalev; Koppel, Ivar

    2013-11-07

    It is usually believed that relativistic effects as described by the Dirac-Schrödinger equation (relative to the classical or time-independent Schrödinger equation) are of little importance in chemistry. A closer look, however, reveals that some important and widely known properties (e.g., gold is yellow, mercury is liquid at room temperature) stem from relativistic effects. So far the influence of relativistic effects on the acid-base properties has been mostly ignored. Here we show that at least for compounds of gold such omission is completely erroneous and would lead to too high basicity and too low acidity values with errors in the range of 25-55 kcal mol(-1) (or 20 to 44 powers of ten in pK(a) units) in the gas-phase. These findings have important implications for the design of new superstrong acids and bases, and for the understanding of gold-catalysed reactions.

  1. Quantitative Structure–Property Relationship (QSPR Models for a Local Quantum Descriptor: Investigation of the 4- and 3-Substituted-Cinnamic Acid Esterification

    Directory of Open Access Journals (Sweden)

    Cláudio E. Rodrigues-Santos

    2015-09-01

    Full Text Available In this work, the theoretical description of the 4- and 3-substituted-cinnamic acid esterification with different electron donating and electron withdrawing groups was performed at the B3LYP and M06-2X levels, as a two-step process: the O-protonation and the nucleophile attack by ethanol. In parallel, an experimental work devoted to the synthesis and characterization of the substituted-cinnamate esters has also been performed. In order to quantify the substituents effects, quantitative structure–property relationship (QSPR models based on the atomic charges, Fukui functions and the Frontier Effective-for-Reaction Molecular Orbitals (FERMO energies were investigated. In fact, the Fukui functions, ƒ+C and ƒ−O, indicated poor correlations for each individual step, and in contrast with the general literature, the O-protonation step is affected both by the FERMO energies and the O-charges of the carbonyl group. Since the process was shown to not be totally described by either charge- or frontier-orbitals, it is proposed to be frontier-charge-miscere controlled. Moreover, the observed trend for the experimental reaction yields suggests that the electron withdrawing groups favor the reaction and the same was observed for Step 2, which can thus be pointed out as the determining step.

  2. Poly(acrylic acid)-coated iron oxide nanoparticles: quantitative evaluation of the coating properties and applications for the removal of a pollutant dye.

    Science.gov (United States)

    Fresnais, J; Yan, M; Courtois, J; Bostelmann, T; Bée, A; Berret, J-F

    2013-04-01

    In this work, 6-12 nm iron oxide nanoparticles were synthesized and coated with poly(acrylic acid) chains of molecular weight 2100 g mol(-1). Based on a quantitative evaluation of the dispersions, the bare and coated particles were thoroughly characterized. The number densities of polymers adsorbed at the particle surface and of available chargeable groups were found to be 1.9±0.3 nm(-2) and 26±4 nm(-2), respectively. Occurring via a multi-site binding mechanism, the electrostatic coupling leads to a solid and resilient anchoring of the chains. To assess the efficacy of the particles for pollutant remediation, the adsorption isotherm of methylene blue molecules, a model of pollutant, was determined. The excellent agreement between the predicted and the measured amounts of adsorbed dyes suggests that most carboxylates participate to the complexation and adsorption mechanisms. An adsorption of 830 mg g(-1) was obtained. This quantity compares well with the highest values available for this dye.

  3. Simple and rapid determination of ferulic acid levels in food and cosmetic samples using paper-based platforms.

    Science.gov (United States)

    Tee-ngam, Prinjaporn; Nunant, Namthip; Rattanarat, Poomrat; Siangproh, Weena; Chailapakul, Orawon

    2013-09-26

    Ferulic acid is an important phenolic antioxidant found in or added to diet supplements, beverages, and cosmetic creams. Two designs of paper-based platforms for the fast, simple and inexpensive evaluation of ferulic acid contents in food and pharmaceutical cosmetics were evaluated. The first, a paper-based electrochemical device, was developed for ferulic acid detection in uncomplicated matrix samples and was created by the photolithographic method. The second, a paper-based colorimetric device was preceded by thin layer chromatography (TLC) for the separation and detection of ferulic acid in complex samples using a silica plate stationary phase and an 85:15:1 (v/v/v) chloroform: methanol: formic acid mobile phase. After separation, ferulic acid containing section of the TLC plate was attached onto the patterned paper containing the colorimetric reagent and eluted with ethanol. The resulting color change was photographed and quantitatively converted to intensity. Under the optimal conditions, the limit of detection of ferulic acid was found to be 1 ppm and 7 ppm (S/N = 3) for first and second designs, respectively, with good agreement with the standard HPLC-UV detection method. Therefore, these methods can be used for the simple, rapid, inexpensive and sensitive quantification of ferulic acid in a variety of samples.

  4. iTRAQ-Based Quantitative Proteomic Analysis of the Antimicrobial Mechanism of Peptide F1 against Escherichia coli.

    Science.gov (United States)

    Miao, Jianyin; Chen, Feilong; Duan, Shan; Gao, Xiangyang; Liu, Guo; Chen, Yunjiao; Dixon, William; Xiao, Hang; Cao, Yong

    2015-08-19

    Antimicrobial peptides have received increasing attention in the agricultural and food industries due to their potential to control pathogens. However, to facilitate the development of novel peptide-based antimicrobial agents, details regarding the molecular mechanisms of these peptides need to be elucidated. The aim of this study was to investigate the antimicrobial mechanism of peptide F1, a bacteriocin found in Tibetan kefir, against Escherichia coli at protein levels using iTRAQ-based quantitative proteomic analysis. In response to treatment with peptide F1, 31 of the 280 identified proteins in E. coli showed alterations in their expression, including 10 down-regulated proteins and 21 up-regulated proteins. These 31 proteins all possess different molecular functions and are involved in different molecular pathways, as is evident in referencing the Kyoto Encyclopedia of Genes and Genomes pathways. Specifically, pathways that were significantly altered in E. coli in response to peptide F1 treatment include the tricarboxylic acid cycle, oxidative phosphorylation, glycerophospholipid metabolism, and the cell cycle-caulobacter pathways, which was also associated with inhibition of the cell growth, induction of morphological changes, and cell death. The results provide novel insights into the molecular mechanisms of antimicrobial peptides.

  5. Kinetic analysis-based quantitation of free radical generation in EPR spin trapping.

    Science.gov (United States)

    Samouilov, Alexandre; Roubaud, Valerie; Kuppusamy, Periannan; Zweier, Jay L

    2004-11-01

    Because short-lived reactive oxygen radicals such as superoxide have been implicated in a variety of disease processes, methods to measure their production quantitatively in biological systems are critical for understanding disease pathophysiology. Electron paramagnetic resonance (EPR) spin trapping is a direct and sensitive technique that has been used to study radical formation in biological systems. Short-lived oxygen free radicals react with the spin trap and produce paramagnetic adducts with much higher stability than that of the free radicals. In many cases, the quantity of the measured adduct is considered to be an adequate measure of the amount of the free radical generated. Although the intensity of the EPR signal reflects the magnitude of free radical generation, the actual quantity of radicals produced may be different due to modulation of the spin adduct kinetics caused by a variety of factors. Because the kinetics of spin trapping in biochemical and cellular systems is a complex process that is altered by the biochemical and cellular environment, it is not always possible to define all of the reactions that occur and the related kinetic parameters of the spin-trapping process. We present a method based on a combination of measured kinetic data for the formation and decay of the spin adduct alone with the parameters that control the kinetics of spin trapping and radical generation. The method is applied to quantitate superoxide trapping with 5-diethoxyphosphoryl-5-methyl-1-pyrroline N-oxide (DEPMPO). In principle, this method is broadly applicable to enable spin trapping-based quantitative determination of free radical generation in complex biological systems.

  6. Radiation-based quantitative bioimaging at the national institute of standards and technology

    Directory of Open Access Journals (Sweden)

    Karam Lisa

    2009-01-01

    Full Text Available Building on a long history of providing physical measurements and standards for medical x rays and nuclear medicine radionuclides, the laboratory has expanded its focus to better support the extensive use of medical physics in the United States today, providing confidence in key results needed for drug and device development and marketing, therapy planning and efficacy and disease screening. In particular, to support more quantitative medical imaging, this laboratory has implemented a program to provide key measurement infrastructure to support radiation-based imaging through developing standard, benchmark phantoms, which contain radioactive sources calibrated to national measurement standards, to allow more quantitative imaging through traceable instrument calibration for clinical trials or patient management. Working closely with colleagues at the National Institutes of Health, Rensselaer Polytechnic Institute, the Food and Drug Administration and Cornell University, this laboratory has taken the initial steps in developing phantoms, and the protocols to use them, for more accurate calibration of positron emission tomography (PET or single-photon emission computed tomography (SPECT cameras, including recently standardizing 68 Ge. X-ray measurements of the laboratory′s recently developed small, resilient and inexpensive length standard phantom have shown the potential usefulness of such a "pocket" phantom for patient-based calibration of computed tomography (alone or with PET systems. The ability to calibrate diagnostic imaging tools in a way that is traceable to national standards will lead to a more quantitative approach; both physician and patient benefit from increased accuracy in treatment planning, as well as increased safety for the patient.

  7. Molecular field analysis and 3D-quantitative structure-activity relationship study (MFA 3D-QSAR) unveil novel features of bile acid recognition at TGR5.

    Science.gov (United States)

    Macchiarulo, Antonio; Gioiello, Antimo; Thomas, Charles; Massarotti, Alberto; Nuti, Roberto; Rosatelli, Emiliano; Sabbatini, Paola; Schoonjans, Kristina; Auwerx, Johan; Pellicciari, Roberto

    2008-09-01

    Bile acids regulate nongenomic actions through the activation of TGR5, a membrane receptor that is G protein-coupled to the induction of adenylate cyclase. In this work, a training set of 43 bile acid derivatives is used to develop a molecular interaction field analysis (MFA) and a 3D-quantitative structure-activity relationship study (3D-QSAR) of TGR5 agonists. The predictive ability of the resulting model is evaluated using an external set of compounds with known TGR5 activity, and six bile acid derivatives whose unknown TGR5 activity is herein assessed with in vitro luciferase assay of cAMP formation. The results show a good predictive model and indicate a statistically relevant degree of correlation between the TGR5 activity and the molecular interaction fields produced by discrete positions of the bile acid scaffold. This information is instrumental to extend on a quantitative basis the current structure-activity relationships of bile acids as TGR5 modulators and will be fruitful to design new potent and selective agonists of the receptor.

  8. Applying generalized hydrophobicity scale of amino acids to quantitative prediction of human leukocyte antigen-A*0201-restricted cytotoxic T lymphocyte epitope

    Institute of Scientific and Technical Information of China (English)

    ZHOU Peng; TIAN Feifei; ZHANG Mengjun; LI Zhiliang

    2006-01-01

    Derived from 149 hydrophobic factors of 20 natural amino acids, a novel amino acid descriptor termed as generalized hydrophobicity scale (GH-scale) was proposed by principal component analysis (PCA). Via genetic algorithm-partial least square (GPLS) method, quantitative structure-activity relationship (QSAR) model was constructed by GH-scale for 152 human leukocyte antigen (HLA)-A*0201-restricted cytotoxic T lymphocyte (CTL) epitopes with the model estimated and cross-validated correlative coefficients of R2 = 0.813 and Q2 = 0.725, respectively. It was indicated that hydrophobic interaction played an important role in HLA-A*0201-CTL interaction, prominently at anchor residues.

  9. Difference between Extra- and Intracellular T1 Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR

    DEFF Research Database (Denmark)

    Karlsson, Magnus; Jensen, Pernille Rose; Ardenkjær-Larsen, Jan Henrik

    2016-01-01

    Incomplete knowledge of the longitudinal relaxation time constant (T1) leads to incorrect assumptions in quantitative kinetic models of cellular systems, studied by hyperpolarized real-time NMR. Using an assay that measures the intracellular signal of small carboxylic acids in living cells...... on the quantification of intracellular metabolic activity. It is expected that the significantly shorter T1 value of the carboxylic moieties inside cells is a result of macromolecular crowding. An artificial cytosol has been prepared and applied to predict the T1 of other carboxylic acids. We demonstrate the value...

  10. Optimal energy window selection of a CZT-based small-animal SPECT for quantitative accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Su-Jin [Department of Radiological Science and Research Institute of Health Science, Yonsei University, Wonju 220-710 (Korea, Republic of); Yu, A. Ram [Laboratory animal center, OSONG Medical Innovation Foundation, Chunguk 363-951 (Korea, Republic of); Department of Nuclear Medicine, College of Medicine, Hanyang University Hospital, Seoul 133-792 (Korea, Republic of); Choi, Yun Young [Department of Nuclear Medicine, College of Medicine, Hanyang University Hospital, Seoul 133-792 (Korea, Republic of); Kim, Kyeong Min [Molecular Imaging Research Center, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Kim, Hee-Joung, E-mail: hjk1@yonsei.ac.kr [Department of Radiological Science and Research Institute of Health Science, Yonsei University, Wonju 220-710 (Korea, Republic of)

    2015-05-11

    Cadmium zinc telluride (CZT)-based small-animal single-photon emission computed tomography (SPECT) has desirable characteristics such as superior energy resolution, but data acquisition for SPECT imaging has been widely performed with a conventional energy window. The aim of this study was to determine the optimal energy window settings for technetium-99 m ({sup 99m}Tc) and thallium-201 ({sup 201}Tl), the most commonly used isotopes in SPECT imaging, using CZT-based small-animal SPECT for quantitative accuracy. We experimentally investigated quantitative measurements with respect to primary count rate, contrast-to-noise ratio (CNR), and scatter fraction (SF) within various energy window settings using Triumph X-SPECT. The two ways of energy window settings were considered: an on-peak window and an off-peak window. In the on-peak window setting, energy centers were set on the photopeaks. In the off-peak window setting, the ratios of energy differences between the photopeak from the lower- and higher-threshold varied from 4:6 to 3:7. In addition, the energy-window width for {sup 99m}Tc varied from 5% to 20%, and that for {sup 201}Tl varied from 10% to 30%. The results of this study enabled us to determine the optimal energy windows for each isotope in terms of primary count rate, CNR, and SF. We selected the optimal energy window that increases the primary count rate and CNR while decreasing SF. For {sup 99m}Tc SPECT imaging, the energy window of 138–145 keV with a 5% width and off-peak ratio of 3:7 was determined to be the optimal energy window. For {sup 201}Tl SPECT imaging, the energy window of 64–85 keV with a 30% width and off-peak ratio of 3:7 was selected as the optimal energy window. Our results demonstrated that the proper energy window should be carefully chosen based on quantitative measurements in order to take advantage of desirable characteristics of CZT-based small-animal SPECT. These results provided valuable reference information for the

  11. Quantitative Determination of Flavonoids and Chlorogenic Acid in the Leaves of Arbutus unedo L. Using Thin Layer Chromatography

    Directory of Open Access Journals (Sweden)

    Željan Maleš

    2013-01-01

    Full Text Available The plant species Arbutus unedo shows numerous beneficial pharmacological effects (antiseptic, antidiabetic, antidiarrheal, astringent, depurative, antioxidant, antihypertensive, antithrombotic, and anti-inflammatory. For the medicinal use, standardization of extracts is a necessity, as different compounds are responsible for different biological activities. In this paper, we analyze monthly changes in the content of quercitrin, isoquercitrin, hyperoside, and chlorogenic acid. Methanolic extracts of the leaves are analyzed by HPTLC for the identification and quantification of individual polyphenol, and DPPH test is used to determine antioxidant activity. Based on the results obtained, the leaves should be collected in January to obtain the highest concentrations of hyperoside and quercitrin (0.35 mg/g and 1.94 mg/g, resp., in June, July, and October for chlorogenic acid (1.45–1.46 mg/g, and for the fraction of quercitrin and isoquercitrin in November (1.98 mg/g and 0.33 mg/g, resp.. Optimal months for the collection of leaves with the maximum recovery of individual polyphenol suggested in this work could direct the pharmacological usage of the polyvalent herbal drugs.

  12. A knowledge based advisory system for acid/base titrations in non-aqueous solvents

    NARCIS (Netherlands)

    Bos, M.; Linden, van der W.E.

    1996-01-01

    A computer program was developed that could advice on the choice of solvent and titrant for acid/base titrations in nonaqueous media. It is shown that the feasibility of a titration in a given solvent can be calculated from solvent properties and intrinsic acid/base properties of the sample componen

  13. Genetic programming based quantitative structure-retention relationships for the prediction of Kovats retention indices.

    Science.gov (United States)

    Goel, Purva; Bapat, Sanket; Vyas, Renu; Tambe, Amruta; Tambe, Sanjeev S

    2015-11-13

    The development of quantitative structure-retention relationships (QSRR) aims at constructing an appropriate linear/nonlinear model for the prediction of the retention behavior (such as Kovats retention index) of a solute on a chromatographic column. Commonly, multi-linear regression and artificial neural networks are used in the QSRR development in the gas chromatography (GC). In this study, an artificial intelligence based data-driven modeling formalism, namely genetic programming (GP), has been introduced for the development of quantitative structure based models predicting Kovats retention indices (KRI). The novelty of the GP formalism is that given an example dataset, it searches and optimizes both the form (structure) and the parameters of an appropriate linear/nonlinear data-fitting model. Thus, it is not necessary to pre-specify the form of the data-fitting model in the GP-based modeling. These models are also less complex, simple to understand, and easy to deploy. The effectiveness of GP in constructing QSRRs has been demonstrated by developing models predicting KRIs of light hydrocarbons (case study-I) and adamantane derivatives (case study-II). In each case study, two-, three- and four-descriptor models have been developed using the KRI data available in the literature. The results of these studies clearly indicate that the GP-based models possess an excellent KRI prediction accuracy and generalization capability. Specifically, the best performing four-descriptor models in both the case studies have yielded high (>0.9) values of the coefficient of determination (R(2)) and low values of root mean squared error (RMSE) and mean absolute percent error (MAPE) for training, test and validation set data. The characteristic feature of this study is that it introduces a practical and an effective GP-based method for developing QSRRs in gas chromatography that can be gainfully utilized for developing other types of data-driven models in chromatography science.

  14. Rapid Quantitation of Ascorbic and Folic Acids in SRM 3280 Multivitamin/Multielement Tablets using Flow-Injection Tandem Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bhandari, Deepak [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

    2013-01-01

    RATIONALE: Ascorbic acid (AA) and folic acid (FA) are water-soluble vitamins and are usually fortified in food and dietary supplements. For the safety of human health, proper intake of these vitamins is recommended. Improvement in the analysis time required for the quantitative determination of these vitamins in food and nutritional formulations is desired. METHODS: A simple and fast (~5 min) in-tube sample preparation was performed, independently for FA and AA, by mixing extraction solvent with a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Quantitative detection was achieved by flow-injection (1 L injection volume) electrospray ionization tandem mass spectrometry (ESI-MS/MS) in negative ion mode using the method of standard addition. RESULTS: Method of standard addition was employed for the quantitative estimation of each vitamin in a sample extract. At least 2 spiked and 1 non-spiked sample extract were injected in triplicate for each quantitative analysis. Given an injection-to-injection interval of approximately 2 min, about 18 min was required to complete the quantitative estimation of each vitamin. The concentration values obtained for the respective vitamins in the standard reference material (SRM) 3280 using this approach were within the statistical range of the certified values provided in the NIST Certificate of Analysis. The estimated limit of detections of FA and AA were 13 and 5.9 ng/g, respectively. CONCLUSIONS: Flow-injection ESI-MS/MS was successfully applied for the rapid quantitation of FA and AA in SRM 3280 multivitamin/multielement tablets.

  15. Diffusion interaction and quantitative analysis of zinc dialkyldithiophosphate content in lube base oils in terahertz regime

    Institute of Scientific and Technical Information of China (English)

    Lu Tian; Kun Zhao; Qingli Zhou; Yulei Shi; Dongmei Zhao; Cunlin Zhang; Songqing Zhao

    2011-01-01

    We investigate the diffusion interaction and quantitative analysis of zinc dialkyldithiophosphate (ZDDP) mixed with lube base oil (LBO) at different concentrations using terahertz time-domain spectroscopy (THz-TDS). When the concentration exceeds 6.78%, the characteristic absorption peaks exhibit significantly shift, and the absorption coefficient peak value is nonlinear against concentration. Moreover, the absorption coefficients of mixed samples follow the Beer's law at a concentration below 6.78%. The quantitative analysis enables a strategy for monitoring the formulation of lubricating oil in real time.%Zinc dialkyldithiophosphate (ZDDP),as a multifunctional additive and inhibitor in petroleum industry,works mainly as antiwear,antioxidant,and anticorrosion agent[1,2].ZDDP mixed with lube base oils (LBOs)has been used to study the effect of concentration on lubrication boundary and tribological properties[3].The concentration of ZDDP in LBOs plays a crucial role in formulation,which is a balance of many different aspects of performance.Lubricating formulation generally results from a molecular diffusion mechanism due to the relative motion of molecules.Molecular diffusion in a steady-state and nonequilibrium system is divided into molecular motion and interaction.Molecular motion,containing the electronic motion,molecular vibration,and molecular rotation,is complicated and multibody.

  16. Smartphone based hand-held quantitative phase microscope using the transport of intensity equation method.

    Science.gov (United States)

    Meng, Xin; Huang, Huachuan; Yan, Keding; Tian, Xiaolin; Yu, Wei; Cui, Haoyang; Kong, Yan; Xue, Liang; Liu, Cheng; Wang, Shouyu

    2016-12-20

    In order to realize high contrast imaging with portable devices for potential mobile healthcare, we demonstrate a hand-held smartphone based quantitative phase microscope using the transport of intensity equation method. With a cost-effective illumination source and compact microscope system, multi-focal images of samples can be captured by the smartphone's camera via manual focusing. Phase retrieval is performed using a self-developed Android application, which calculates sample phases from multi-plane intensities via solving the Poisson equation. We test the portable microscope using a random phase plate with known phases, and to further demonstrate its performance, a red blood cell smear, a Pap smear and monocot root and broad bean epidermis sections are also successfully imaged. Considering its advantages as an accurate, high-contrast, cost-effective and field-portable device, the smartphone based hand-held quantitative phase microscope is a promising tool which can be adopted in the future in remote healthcare and medical diagnosis.

  17. Towards quantitative mass spectrometry-based metabolomics in microbial and mammalian systems.

    Science.gov (United States)

    Kapoore, Rahul Vijay; Vaidyanathan, Seetharaman

    2016-10-28

    Metabolome analyses are a suite of analytical approaches that enable us to capture changes in the metabolome (small molecular weight components, typically less than 1500 Da) in biological systems. Mass spectrometry (MS) has been widely used for this purpose. The key challenge here is to be able to capture changes in a reproducible and reliant manner that is representative of the events that take place in vivo Typically, the analysis is carried out in vitro, by isolating the system and extracting the metabolome. MS-based approaches enable us to capture metabolomic changes with high sensitivity and resolution. When developing the technique for different biological systems, there are similarities in challenges and differences that are specific to the system under investigation. Here, we review some of the challenges in capturing quantitative changes in the metabolome with MS based approaches, primarily in microbial and mammalian systems.This article is part of the themed issue 'Quantitative mass spectrometry'. © 2016 The Author(s).

  18. Plasmonic Metasurfaces Based on Nanopin-Cavity Resonator for Quantitative Colorimetric Ricin Sensing.

    Science.gov (United States)

    Fan, Jiao-Rong; Zhu, Jia; Wu, Wen-Gang; Huang, Yun

    2017-01-01

    In view of the toxic potential of a bioweapon threat, rapid visual recognition and sensing of ricin has been of considerable interest while remaining a challenging task up to date. In this study, a gold nanopin-based colorimetric sensor is developed realizing a multicolor variation for ricin qualitative recognition and analysis. It is revealed that such plasmonic metasurfaces based on nanopin-cavity resonator exhibit reflective color appearance, due to the excitation of standing-wave resonances of narrow bandwidth in visible region. This clear color variation is a consequence of the reflective color mixing defined by different resonant wavelengths. In addition, the colored metasurfaces appear sharp color difference in a narrow refractive index range, which makes them especially well-suited for sensing applications. Therefore, this antibody-functionalized nanopin-cavity biosensor features high sensitivity and fast response, allowing for visual quantitative ricin detection within the range of 10-120 ng mL(-1) (0.15 × 10(-9) -1.8 × 10(-9) m), a limit of detection of 10 ng mL(-1) , and the typical measurement time of less than 10 min. The on-chip integration of such nanopin metasurfaces to portable colorimetric microfluidic device may be envisaged for the quantitative studies of a variety of biochemical molecules.

  19. Pion Fluctuation in High Energy Collisions - A Chaos-based Quantitative Estimation with Visibility Graph Technique

    CERN Document Server

    Bhaduri, Susmita

    2016-01-01

    We propose a new approach for studying pion fluctuation for deeper understanding of the dynamical process involved, from a perspective of fBm-based complex network analysis method called Visibility graph Analysis. This chaos-based, rigorous, non-linear technique is applied to study the erratic behavior of multipion production in \\textbf{$\\pi^{-}$-Ag/Br} interactions at $350$ GeV. This method can offer reliable results with finite data points. The \\textbf{Power of Scale-freeness of Visibility Graph} denoted by-\\textit{PSVG} is a measure of fractality, which can be used as a quantitative parameter for the assessment of the state of a chaotic system. The event-wise fluctuation of the multipion production process can be described by this parameter-\\textit{PSVG}. From the analysis of the \\textit{PSVG} parameter, we can quantitatively confirm that fractal behavior of the particle production process depends on the target excitation and also the fractality decreases with the increase of target excitation.

  20. Quantitative breast tissue characterization using grating-based x-ray phase-contrast imaging

    Science.gov (United States)

    Willner, M.; Herzen, J.; Grandl, S.; Auweter, S.; Mayr, D.; Hipp, A.; Chabior, M.; Sarapata, A.; Achterhold, K.; Zanette, I.; Weitkamp, T.; Sztrókay, A.; Hellerhoff, K.; Reiser, M.; Pfeiffer, F.

    2014-04-01

    X-ray phase-contrast imaging has received growing interest in recent years due to its high capability in visualizing soft tissue. Breast imaging became the focus of particular attention as it is considered the most promising candidate for a first clinical application of this contrast modality. In this study, we investigate quantitative breast tissue characterization using grating-based phase-contrast computed tomography (CT) at conventional polychromatic x-ray sources. Different breast specimens have been scanned at a laboratory phase-contrast imaging setup and were correlated to histopathology. Ascertained tumor types include phylloides tumor, fibroadenoma and infiltrating lobular carcinoma. Identified tissue types comprising adipose, fibroglandular and tumor tissue have been analyzed in terms of phase-contrast Hounsfield units and are compared to high-quality, high-resolution data obtained with monochromatic synchrotron radiation, as well as calculated values based on tabulated tissue properties. The results give a good impression of the method’s prospects and limitations for potential tumor detection and the associated demands on such a phase-contrast breast CT system. Furthermore, the evaluated quantitative tissue values serve as a reference for simulations and the design of dedicated phantoms for phase-contrast mammography.

  1. A parallel and quantitative cell migration assay using a novel multi-well-based device.

    Science.gov (United States)

    Quan, Qianghua; Zhang, Shuwen; Wang, Xudong; Ouyang, Qi; Wang, Yugang; Yang, Gen; Luo, Chunxiong

    2016-12-01

    Cell migration assays for different chemical environments are important for both scientists and clinicians searching for new therapeutics. In this study, we developed a multi-well-based microfluidic chip that has multiple units for different conditions. In each unit, cells can be patterned and then released to observe their migration. Automatic image analysis and model-based data processing were developed to describe the integrated cell migration assay precisely and quickly. As a demonstration, the migration behaviors of two types of cells in eight chemical conditions were studied. The results showed that supplementation with transforming growth factor-β(TGF-β) significantly promoted the migration of MCF-7 and MCF-10 A cells compared to several growth factors, such as Epidermal Growth Factor(EGF) and basic fibroblast growth factor(bFGF), as well as a control sample. Cells can migrate particularly fast with two or more mixed supplementary factors, such as TGF-β + bFGF + EGF, which indicated a synergy effect. Thus, this chip could be used to quantitatively observe cancer cell migration and demonstrated great potential for use in quantitative migration studies and chemical screening.

  2. Dynamic and Quantitative Method of Analyzing Service Consistency Evolution Based on Extended Hierarchical Finite State Automata

    Directory of Open Access Journals (Sweden)

    Linjun Fan

    2014-01-01

    Full Text Available This paper is concerned with the dynamic evolution analysis and quantitative measurement of primary factors that cause service inconsistency in service-oriented distributed simulation applications (SODSA. Traditional methods are mostly qualitative and empirical, and they do not consider the dynamic disturbances among factors in service’s evolution behaviors such as producing, publishing, calling, and maintenance. Moreover, SODSA are rapidly evolving in terms of large-scale, reusable, compositional, pervasive, and flexible features, which presents difficulties in the usage of traditional analysis methods. To resolve these problems, a novel dynamic evolution model extended hierarchical service-finite state automata (EHS-FSA is constructed based on finite state automata (FSA, which formally depict overall changing processes of service consistency states. And also the service consistency evolution algorithms (SCEAs based on EHS-FSA are developed to quantitatively assess these impact factors. Experimental results show that the bad reusability (17.93% on average is the biggest influential factor, the noncomposition of atomic services (13.12% is the second biggest one, and the service version’s confusion (1.2% is the smallest one. Compared with previous qualitative analysis, SCEAs present good effectiveness and feasibility. This research can guide the engineers of service consistency technologies toward obtaining a higher level of consistency in SODSA.

  3. FRET-based genetically-encoded sensors for quantitative monitoring of metabolites.

    Science.gov (United States)

    Mohsin, Mohd; Ahmad, Altaf; Iqbal, Muhammad

    2015-10-01

    Neighboring cells in the same tissue can exist in different states of dynamic activities. After genomics, proteomics and metabolomics, fluxomics is now equally important for generating accurate quantitative information on the cellular and sub-cellular dynamics of ions and metabolite, which is critical for functional understanding of organisms. Various spectrometry techniques are used for monitoring ions and metabolites, although their temporal and spatial resolutions are limited. Discovery of the fluorescent proteins and their variants has revolutionized cell biology. Therefore, novel tools and methods targeting sub-cellular compartments need to be deployed in specific cells and targeted to sub-cellular compartments in order to quantify the target-molecule dynamics directly. We require tools that can measure cellular activities and protein dynamics with sub-cellular resolution. Biosensors based on fluorescence resonance energy transfer (FRET) are genetically encoded and hence can specifically target sub-cellular organelles by fusion to proteins or targetted sequences. Since last decade, FRET-based genetically encoded sensors for molecules involved in energy production, reactive oxygen species and secondary messengers have helped to unravel key aspects of cellular physiology. This review, describing the design and principles of sensors, presents a database of sensors for different analytes/processes, and illustrate examples of application in quantitative live cell imaging.

  4. 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...... 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...... contributes to pancreatic diseases including cystic fibrosis, pancreatitis, and cancer. © 2013 Novak, Haanes and Wang....

  5. Scientifically Based Research in Quantitative Literacy: Guidelines for Building a Knowledge Base

    Directory of Open Access Journals (Sweden)

    Richard L. Scheaffer

    2008-01-01

    Full Text Available Research in quantitative literacy (QL is in its infancy, so now is the time to begin a regimen for healthy growth into adulthood. As a new discipline still defining itself, QL has the opportunity to build a sound infrastructure for accumulating a solid body of interconnected research that will serve the discipline well in years to come. To that end, much can be learned from recent studies of the weaknesses of mathematics education research and recommendations on how to overcome them. Mathematics education lacks a strong research foundation, one that is scientific, cumulative, interconnected, and intertwined with teaching practice. These weaknesses can be alleviated by following a model built around five key components of a high-quality research program: generating ideas, framing those ideas in a research setting, examining the research questions in small studies, generalizing the results in larger and more refined studies, and extending the results over time and location. Single research projects having only one or two of these components should link to others so that a viable research program that is interconnected and cumulative can be identified and effectively used to improve both teaching practice and future research. Detailed reporting guidelines for each component of the model are outlined in the following sections.

  6. Qualitative and quantitative analyses of Compound Danshen extract based on (1)H NMR method and its application for quality control.

    Science.gov (United States)

    Yan, Kai-Jing; Chu, Yang; Huang, Jian-Hua; Jiang, Miao-Miao; Li, Wei; Wang, Yue-Fei; Huang, Hui-Yong; Qin, Yu-Hui; Ma, Xiao-Hui; Zhou, Shui-Ping; Sun, Henry; Wang, Wei

    2016-11-30

    In this study, a new approach using (1)H NMR spectroscopy combined with chemometrics method was developed for qualitative and quantitative analyses of extracts of Compound Danshen Dripping Pills (CDDP). For the qualitative analysis, some metabolites presented in Compound Danshen extract (CDE, extraction intermediate of CDDP) were detected, including phenolic acids, saponins, saccharides, organic acids and amino acids, by the proposed (1)H NMR method, and metabolites profiles were further analyzed by selected chemometrics algorithms to define the threshold values for product quality evaluation. Moreover, three main phenolic acids (danshensu, salvianolic acid B, and procatechuic aldehyde) in CDE were determined simultaneously, and method validation in terms of linearity, precision, repeatability, accuracy, and stability of the dissolved target compounds in solution was performed. The average recoveries varied between 84.20% and 110.75% while the RSDs were below 6.34% for the three phenolic acids. This (1)H NMR method offers an integral view of the extract composition, allows the qualitative and quantitative analysis of CDDP, and has the potential to be a supplementary tool to UPLC/HPLC for quality assessment of Chinese herbal medicines.

  7. Quantitative generalized ratiometric fluorescence spectroscopy for turbid media based on probe encapsulated by biologically localized embedding

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Xiu-Fang; Chen, Zeng-Ping, E-mail: zpchen2002@hotmail.com; Cui, Yin-Yin; Hu, Yuan-Liang; Yu, Ru-Qin

    2016-05-19

    PEBBLE (probe encapsulated by biologically localized embedding) nanosensor encapsulating an intensity-based fluorescence indicator and an inert reference fluorescence dye inside the pores of stable matrix can be used as a generalized wavelength-ratiometric probe. However, the lack of an efficient quantitative model render the choices of inert reference dyes and intensity-based fluorescence indicators used in PEBBLEs based generalized wavelength-ratiometric probes rather limited. In this contribution, an extended quantitative fluorescence model was derived specifically for generalized wavelength-ratiometric probes based on PEBBLE technique (QFM{sub GRP}) with a view to simplify the design of PEBBLEs and hence further extend their application potentials. The effectiveness of QFM{sub GRP} has been tested on the quantitative determination of free Ca{sup 2+} in both simulated and real turbid media using a Ca{sup 2+} sensitive PEBBLE nanosensor encapsulating Rhod-2 and eosin B inside the micropores of stable polyacrylamide matrix. Experimental results demonstrated that QFM{sub GRP} could realize precise and accurate quantification of free Ca{sup 2+} in turbid samples, even though there is serious overlapping between the fluorescence excitation peaks of eosin B and Ca{sup 2+} bound Rhod-2. The average relative predictive error value of QFM{sub GRP} for the test simulated turbid samples was 5.9%, about 2–4 times lower than the corresponding values of partial least squares calibration model and the empirical ratiometric model based on the ratio of fluorescence intensities at the excitation peaks of Ca{sup 2+} bound Rhod-2 and eosin B. The recovery rates of QFM{sub GRP} for the real and spiked turbid samples varied from 93.1% to 101%, comparable to the corresponding results of atomic absorption spectrometry. - Highlights: • An advanced model was derived for generalized wavelength-ratiometric PEBBLEs. • The model can simplify the design of generalized wavelength

  8. Molecular mechanisms of acid-base sensing by the kidney.

    Science.gov (United States)

    Brown, Dennis; Wagner, Carsten A

    2012-05-01

    A major function of the kidney is to collaborate with the respiratory system to maintain systemic acid-base status within limits compatible with normal cell and organ function. It achieves this by regulating the excretion and recovery of bicarbonate (mainly in the proximal tubule) and the secretion of buffered protons (mainly in the distal tubule and collecting duct). How proximal tubular cells and distal professional proton transporting (intercalated) cells sense and respond to changes in pH, bicarbonate, and CO(2) status is a question that has intrigued many generations of renal physiologists. Over the past few years, however, some candidate molecular pH sensors have been identified, including acid/alkali-sensing receptors (GPR4, InsR-RR), kinases (Pyk2, ErbB1/2), pH-sensitive ion channels (ASICs, TASK, ROMK), and the bicarbonate-stimulated adenylyl cyclase (sAC). Some acid-sensing mechanisms in other tissues, such as CAII-PDK2L1 in taste buds, might also have similar roles to play in the kidney. Finally, the function of a variety of additional membrane channels and transporters is altered by pH variations both within and outside the cell, and the expression of several metabolic enzymes are altered by acid-base status in parts of the nephron. Thus, it is possible that a master pH sensor will never be identified. Rather, the kidney seems equipped with a battery of molecules that scan the epithelial cell environment to mount a coordinated physiologic response that maintains acid-base homeostasis. This review collates current knowledge on renal acid-base sensing in the context of a whole organ sensing and response process.

  9. A Quantitative Analysis on Two RFS-Based Filtering Methods for Multicell Tracking

    Directory of Open Access Journals (Sweden)

    Yayun Ren

    2014-01-01

    Full Text Available Multiobject filters developed from the theory of random finite sets (RFS have recently become well-known methods for solving multiobject tracking problem. In this paper, we present two RFS-based filtering methods, Gaussian mixture probability hypothesis density (GM-PHD filter and multi-Bernoulli filter, to quantitatively analyze their performance on tracking multiple cells in a series of low-contrast image sequences. The GM-PHD filter, under linear Gaussian assumptions on the cell dynamics and birth process, applies the PHD recursion to propagate the posterior intensity in an analytic form, while the multi-Bernoulli filter estimates the multitarget posterior density through propagating the parameters of a multi-Bernoulli RFS that approximates the posterior density of multitarget RFS. Numerous performance comparisons between the two RFS-based methods are carried out on two real cell images sequences and demonstrate that both yield satisfactory results that are in good agreement with manual tracking method.

  10. A Quantitative Analysis of an EEG Epileptic Record Based on MultiresolutionWavelet Coefficients

    Directory of Open Access Journals (Sweden)

    Mariel Rosenblatt

    2014-11-01

    Full Text Available The characterization of the dynamics associated with electroencephalogram (EEG signal combining an orthogonal discrete wavelet transform analysis with quantifiers originated from information theory is reviewed. In addition, an extension of this methodology based on multiresolution quantities, called wavelet leaders, is presented. In particular, the temporal evolution of Shannon entropy and the statistical complexity evaluated with different sets of multiresolution wavelet coefficients are considered. Both methodologies are applied to the quantitative EEG time series analysis of a tonic-clonic epileptic seizure, and comparative results are presented. In particular, even when both methods describe the dynamical changes of the EEG time series, the one based on wavelet leaders presents a better time resolution.

  11. Quantitative Evaluation of the Total Magnetic Moments of Colloidal Magnetic Nanoparticles: A Kinetics-based Method.

    Science.gov (United States)

    Liu, Haiyi; Sun, Jianfei; Wang, Haoyao; Wang, Peng; Song, Lina; Li, Yang; Chen, Bo; Zhang, Yu; Gu, Ning

    2015-06-08

    A kinetics-based method is proposed to quantitatively characterize the collective magnetization of colloidal magnetic nanoparticles. The method is based on the relationship between the magnetic force on a colloidal droplet and the movement of the droplet under a gradient magnetic field. Through computational analysis of the kinetic parameters, such as displacement, velocity, and acceleration, the magnetization of colloidal magnetic nanoparticles can be calculated. In our experiments, the values measured by using our method exhibited a better linear correlation with magnetothermal heating, than those obtained by using a vibrating sample magnetometer and magnetic balance. This finding indicates that this method may be more suitable to evaluate the collective magnetism of colloidal magnetic nanoparticles under low magnetic fields than the commonly used methods. Accurate evaluation of the magnetic properties of colloidal nanoparticles is of great importance for the standardization of magnetic nanomaterials and for their practical application in biomedicine.

  12. A fluorescence-based quantitative real-time PCR assay for accurate Pocillopora damicornis species identification

    Science.gov (United States)

    Thomas, Luke; Stat, Michael; Evans, Richard D.; Kennington, W. Jason

    2016-09-01

    Pocillopora damicornis is one of the most extensively studied coral species globally, but high levels of phenotypic plasticity within the genus make species identification based on morphology alone unreliable. As a result, there is a compelling need to develop cheap and time-effective molecular techniques capable of accurately distinguishing P. damicornis from other congeneric species. Here, we develop a fluorescence-based quantitative real-time PCR (qPCR) assay to genotype a single nucleotide polymorphism that accurately distinguishes P. damicornis from other morphologically similar Pocillopora species. We trial the assay across colonies representing multiple Pocillopora species and then apply the assay to screen samples of Pocillopora spp. collected at regional scales along the coastline of Western Australia. This assay offers a cheap and time-effective alternative to Sanger sequencing and has broad applications including studies on gene flow, dispersal, recruitment and physiological thresholds of P. damicornis.

  13. Acid-base metabolism: implications for kidney stones formation.

    Science.gov (United States)

    Hess, Bernhard

    2006-04-01

    The physiology and pathophysiology of renal H+ ion excretion and urinary buffer systems are reviewed. The main focus is on the two major conditions related to acid-base metabolism that cause kidney stone formation, i.e., distal renal tubular acidosis (dRTA) and abnormally low urine pH with subsequent uric acid stone formation. Both the entities can be seen on the background of disturbances of the major urinary buffer system, NH3+ NH4+. On the one hand, reduced distal tubular secretion of H+ ions results in an abnormally high urinary pH and either incomplete or complete dRTA. On the other hand, reduced production/availability of NH4+ is the cause of an abnormally low urinary pH, which predisposes to uric acid stone formation. Most recent research indicates that the latter abnormality may be a renal manifestation of the increasingly prevalent metabolic syndrome. Despite opposite deviations from normal urinary pH values, both the dRTA and uric acid stone formation due to low urinary pH require the same treatment, i.e., alkali. In the dRTA, alkali is needed for improving the body's buffer capacity, whereas the goal of alkali treatment in uric acid stone formers is to increase the urinary pH to 6.2-6.8 in order to minimize uric acid crystallization.

  14. Current chemical concepts of acids and bases and their application to anionic ("acid") and cationic ("basic") dyes.

    Science.gov (United States)

    Puchtler, H; Meloan, S N; Spencer, M

    1985-01-01

    In biomedical studies, dyes are divided into "acid" and "basic" dyes. This classification cannot be reconciled with current chemical definitions of acids and bases. Brönsted-Lowry acids are compounds that can donate protons; bases are proton acceptors. The definition of acids and bases is independent of the electric charge, i.e. acids and bases can be neutral, anionic or cationic. Reactions between acids and bases result in formation of new acid-base pairs. Lewis acids and bases do not depend on a particular element, but are characterized by their electronic configurations. Lewis bases are electron donors; Lewis acids are electron acceptors. This classification is also unrelated to the electric charge. Lewis acids and bases interact by formation of coordinate covalent bonds. In histochemistry and histology, dyes containing -SO3-, -COO- and/or -O- groups are classified as "acid" dyes. However, such compounds are electron pair donors and hence Brönsted-Lowry and Lewis anionic bases. Dyes carrying a positive charge are termed "basic" dyes. Chemically, many cationic dyes are Lewis acids because they can add a base, e.g. OH-, acetate, halides. The hypothesis that transformation of -NH2 into ammonium groups imparts "basic" properties to dyes is untenable; ammonium groups are proton donors and hence acids. Furthermore, conversion of an amino into an ammonium group blocks a lone electron pair and the color of the dye changes drastically, e.g. from violet to green and yellow. It appears therefore highly unlikely that ammonium groups are responsible for binding of cationic ("basic") dyes. In histochemistry, it is usually not of critical importance whether anionic or cationic dyes are chemically acids or bases.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Interactions between acid- and base-functionalized surfaces

    NARCIS (Netherlands)

    Giesbers, M.; Kleijn, J.M.; Cohen Stuart, M.A.

    2002-01-01

    In this paper we present an AFM force study on interactions between chemically modified surfaces. Surfaces with terminal groups of either NH2 or COOH were obtained by chemisorption of a silane-based compound (3-amino-propyltriethoxysilane) on silica or a thiol compound (11-mercapto undecanoic acid)

  16. 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…

  17. Turkish Prospective Chemistry Teachers' Alternative Conceptions about Acids and Bases

    Science.gov (United States)

    Boz, Yezdan

    2009-01-01

    The purpose of this study was to obtain prospective chemistry teachers' conceptions about acids and bases concepts. Thirty-eight prospective chemistry teachers were the participants. Data were collected by means of an open-ended questionnaire and semi-structured interviews. Analysis of data indicated that most prospective teachers did not have…

  18. Asymmetric bipolar membranes in acid-base electrodialysis

    NARCIS (Netherlands)

    Wilhelm, Friedrich G.; Punt, Ineke; Vegt, van der Nico F.A.; Strathmann, H.; Wessling, M.

    2002-01-01

    In this experimental study, the influence of asymmetric bipolar membranes on the salt impurities in the acid and base product is investigated. The thickness of one, the other, or both ion-permeable layers of a bipolar membrane is increased. With increased layer thickness, the current-voltage curves

  19. 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)

  20. Photoresponsive self-assemblies based on fatty acids.

    Science.gov (United States)

    Fameau, A-L; Arnould, A; Lehmann, M; von Klitzing, R

    2015-02-18

    Photoresponsive surfactant system based on fatty acids has been developed by the introduction in aqueous solution of a photoacid generator (PAG). Self-assembly transitions are triggered by UV irradiation due to a pH change induced by the presence of PAG.

  1. 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…

  2. Turkish Prospective Chemistry Teachers' Alternative Conceptions about Acids and Bases

    Science.gov (United States)

    Boz, Yezdan

    2009-01-01

    The purpose of this study was to obtain prospective chemistry teachers' conceptions about acids and bases concepts. Thirty-eight prospective chemistry teachers were the participants. Data were collected by means of an open-ended questionnaire and semi-structured interviews. Analysis of data indicated that most prospective teachers did not have…

  3. Comparison of isotope-labeled amino acid incorporation rates (CILAIR) provides a quantitative method to study tissue secretomes.

    Science.gov (United States)

    Roelofsen, Han; Dijkstra, Martijn; Weening, Desiree; de Vries, Marcel P; Hoek, Annemieke; Vonk, Roel J

    2009-02-01

    Adipose tissue is an endocrine organ involved in regulation of whole-body energy metabolism via storage of lipids and secretion of various peptide hormones (adipokines). We previously characterized the adipose tissue secretome and showed that [(13)C]lysine incorporation into secreted proteins can be used to determine the origin of identified proteins. In the present study we determined the effect of insulin on the secretome by comparing incorporation rates of (13)C-labeled lysine in the presence and absence of insulin. Human visceral adipose tissue from one patient was divided over six dishes. After subsequent washes to remove serum proteins, [(13)C]lysine-containing medium was added. Three dishes also received 60 nm insulin. The other three were controls. After 72 h of culture, media were collected and processed separately, involving concentration by ultrafiltration and fractionation by SDS-PAGE followed by in-gel digestion of excised bands and LC-MS/MS analyses. The obtained spectra were used for database searching and calculation of heavy/light ratios. The three control data sets shared 342 proteins of which 156 were potentially secreted and contained label. The three insulin-derived data sets shared 361 proteins of which 141 were potentially secreted and contained label. After discarding secreted proteins with very low label incorporation, 121 and 113 proteins remained for control and insulin data sets, respectively. The average coefficient of variation for control triplicates was 10.0% and for insulin triplicates was 18.3%. By comparing heavy/light ratios in the absence and presence of insulin we found 24 up-regulated proteins and four down-regulated proteins, and 58 proteins showed no change. Proteins involved in the endoplasmic reticulum stress response and in extracellular matrix remodeling were up-regulated by insulin. In conclusion, comparison of isotope-labeled amino acid incorporation rates (CILAIR) allows quantitative assessment of changes in protein

  4. Effect of Animal and Industrial Trans Fatty Acids on HDL and LDL Cholesterol Levels in Humans - A Quantitative Review

    NARCIS (Netherlands)

    Brouwer, I.A.; Wanders, A.J.; Katan, M.B.

    2010-01-01

    Background: Trans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower HDL cholesterol, raise LDL cholesterol, and increase the risk of coronary heart disease. The effects of conjugated linoleic acid an

  5. Plasmonics-based SERS nanobiosensor for homogeneous nucleic acid detection.

    Science.gov (United States)

    Wang, Hsin-Neng; Fales, Andrew M; Vo-Dinh, Tuan

    2015-05-01

    Developing a simple and efficient nucleic acid detection technology is essential for clinical diagnostics. Here, we describe a new conceptually simple and selective "turn on" plasmonics-based nanobiosensor, which integrates non-enzymatic DNA strand-displacement hybridization for specific nucleic acid target identification with surface-enhanced Raman scattering (SERS) detection. This SERS nanobiosensor is a target label-free, and rapid nanoparticle-based biosensing system using a homogeneous assay format that offers a simple and efficient tool for nucleic acid diagnostics. Our results showed that the nanobiosensor provided a limit of detection of ~0.1nM (200amol) in the current bioassay system, and exhibited high specificity for single nucleotide mismatch discrimination. Surface-enhanced Raman scattering (SERS) is a sensitive technique that enhances Raman scattering by molecules adsorbed on rough metal surfaces. The enhancement means that the technique may even detect single molecules. In this article, the authors describe a simple and efficient nucleic acid detection technology using SERS, with "OFF-to-ON" signal switch upon nucleic acid target identification and capture, which provides high sensitivity and specificity for single nucleotide mismatch discrimination. This new technology will be most welcomed in clinical diagnostics. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Parallel proton transfer pathways in aqueous acid-base reactions

    OpenAIRE

    Cox, M. J.; Bakker, H.J.

    2008-01-01

    We study the mechanism of proton transfer (PT) between the photoacid 8-hydroxy-1,3, 6-pyrenetrisulfonic acid (HPTS) and the base chloroacetate in aqueous solution. We investigate both proton and deuteron transfer reactions in solutions with base concentrations ranging from 0.25M to 4M. Using femtosecond midinfrared spectroscopy, we probe the vibrational responses of HPTS, its conjugate photobase, the hydrated proton/deuteron, and chloroacetate. The measurement of these four resonances allows ...

  7. Quantitative Detection Method of Hydroxyapatite Nanoparticles Based on Eu(3+) Fluorescent Labeling in Vitro and in Vivo.

    Science.gov (United States)

    Xie, Yunfei; Perera, Thalagalage Shalika Harshani; Li, Fang; Han, Yingchao; Yin, Meizhen

    2015-11-04

    One major challenge for application of hydroxyapatite nanoparticles (nHAP) in nanomedicine is the quantitative detection method. Herein, we exploited one quantitative detection method for nHAP based on the Eu(3+) fluorescent labeling via a simple chemical coprecipitation method. The trace amount of nHAP in cells and tissues can be quantitatively detected on the basis of the fluorescent quantitative determination of Eu(3+) ions in nHAP crystal lattice. The lowest concentration of Eu(3+) ions that can be quantitatively detected is 0.5 nM using DELFIA enhancement solution. This methodology can be broadly applicable for studying the tissue distribution and metabolization of nHAP in vivo.

  8. [Quantitative evaluation of printing accuracy and tissue surface adaptation of mandibular complete denture polylactic acid pattern fabricated by fused deposition modeling technology].

    Science.gov (United States)

    Deng, K H; Wang, Y; Chen, H; Zhao, Y J; Zhou, Y S; Sun, Y C

    2017-06-09

    Objective: To quantitatively evaluate the adaptation of polylactic acid (PLA) pattern of mandibular complete denture fabricated by fused deposition modeling (FDM) technology. Methods: A mandibular complete denture digital model was designed through a complete denture design software based on a pair of standard maxillomandibular edentulous plaster model and their occlusion bases. Ten PLA mandibular complete dentures were printed with a FDM machine. The dentures were scanned with and without the plaster model using a three-dimensional (3D) scanner. In Geomagic software, the scanning data of printed dentures were registered to its computer aided design (CAD) data, and the printing error was analyzed using the multipoint registration command. For quantitatively evaluating the adaptation of the denture, the data of plaster model and PLA denture were registered to the whole data of denture located in the plaster model using the best-fit alignment command, the 3D deviation of the plaster model and tissue surface of the denture represent the space between them. The overall area was separated into three parts: primary stress-bearing area, secondary stress-bearing area and border seal area, and the average deviations of these three parts were measured. The values were analyzed using analysis of variance. Results: Compared with the CAD data, the printing error was (0.013±0.004) mm. The overall 3D deviation between PLA denture and plaster model was (0.164±0.033) mm, in which the primary stress-bearing area was (0.165± 0.045) mm, the secondary stress-bearing area was (0.153 ± 0.027) mm, the border seal area was (0.186 ± 0.043) mm. These showed a good fit in the majority parts of the FDM denture to the plaster model. No statistically significant difference was observed between the three areas (F=1.857, P=0.175>0.05). Conclusions: Combined with the 3D scanning, CAD and FDM technology, a FDM 3D printing process of complete denture for injection moulding can be established. As

  9. Thermal infrared images to quantify thermal ablation effects of acid and base on target tissues

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ran, E-mail: jliubme@tsinghua.edu.cn, E-mail: liuran@tsinghua.edu.cn; Liu, Jing, E-mail: jliubme@tsinghua.edu.cn, E-mail: liuran@tsinghua.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); Wang, Jia [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2015-07-15

    Hyperthermia (42-46°C), treatment of tumor tissue through elevated temperature, offers several advantages including high cost-effectiveness, highly targeted ablation and fewer side effects and hence higher safety level over traditional therapies such as chemotherapy and radiotherapy. Recently, hyperthermia using heat release through exothermic acid-base neutralization comes into view owing to its relatively safe products of salt and water and highly confined ablation. However, lack of quantitative understanding of the spatial and temporal temperature profiles that are produced by simultaneous diffusion of liquid chemical and its chemical reaction within tumor tissue impedes the application of this method. This article is dedicated to quantify thermal ablation effects of acid and base both individually and as in neutralization via infrared captured thermal images. A theoretical model is used to approximate specific heat absorption rate (SAR) based on experimental measurements that contrast two types of tissue, normal pork and pig liver. According to the computation, both pork and liver tissue has a higher ability in absorbing hydrochloric acid (HCl) than sodium hydroxide, hence suggesting that a reduced dosage for HCl is appropriate in a surgery. The heating effect depends heavily on the properties of tissue types and amount of chemical reagents administered. Given thermal parameters such as SAR for different tissues, a computational model can be made in predicting temperature transitions which will be helpful in planning and optimizing surgical hyperthermia procedures.

  10. Thermal infrared images to quantify thermal ablation effects of acid and base on target tissues

    Directory of Open Access Journals (Sweden)

    Ran Liu

    2015-07-01

    Full Text Available Hyperthermia (42-46°C, treatment of tumor tissue through elevated temperature, offers several advantages including high cost-effectiveness, highly targeted ablation and fewer side effects and hence higher safety level over traditional therapies such as chemotherapy and radiotherapy. Recently, hyperthermia using heat release through exothermic acid-base neutralization comes into view owing to its relatively safe products of salt and water and highly confined ablation. However, lack of quantitative understanding of the spatial and temporal temperature profiles that are produced by simultaneous diffusion of liquid chemical and its chemical reaction within tumor tissue impedes the application of this method. This article is dedicated to quantify thermal ablation effects of acid and base both individually and as in neutralization via infrared captured thermal images. A theoretical model is used to approximate specific heat absorption rate (SAR based on experimental measurements that contrast two types of tissue, normal pork and pig liver. According to the computation, both pork and liver tissue has a higher ability in absorbing hydrochloric acid (HCl than sodium hydroxide, hence suggesting that a reduced dosage for HCl is appropriate in a surgery. The heating effect depends heavily on the properties of tissue types and amount of chemical reagents administered. Given thermal parameters such as SAR for different tissues, a computational model can be made in predicting temperature transitions which will be helpful in planning and optimizing surgical hyperthermia procedures.

  11. Nucleic Acid Base Analog FRET-Pair Facilitating Detailed Structural Measurements in Nucleic Acid Containing Systems

    DEFF Research Database (Denmark)

    Börjesson, Karl; Preus, Søren; El-Sagheer, Afaf

    2009-01-01

    distances covering up to more than one turn of the DNA duplex. Importantly, we show that the rigid stacking of the two base analogs, and consequently excellent control of their exact positions and orientations, results in a high control of the orientation factor and hence very distinct FRET changes...... as the number of bases separating tCO and tC(nitro) is varied. A set of DNA strands containing the FRET-pair at wisely chosen locations will, thus, make it possible to accurately distinguish distance- from orientation-changes using FRET. In combination with the good nucleobase analog properties, this points...... toward detailed studies of the inherent dynamics of nucleic acid structures. Moreover, the placement of FRET-pair chromophores inside the base stack will be a great advantage in studies where other (biomacro)molecules interact with the nucleic acid. Lastly, our study gives possibly the first truly solid...

  12. A high-throughput microtiter plate based method for the determination of peracetic acid and hydrogen peroxide.

    Directory of Open Access Journals (Sweden)

    Karson S Putt

    Full Text Available Peracetic acid is gaining usage in numerous industries who have found a myriad of uses for its antimicrobial activity. However, rapid high throughput quantitation methods for peracetic acid and hydrogen peroxide are lacking. Herein, we describe the development of a high-throughput microtiter plate based assay based upon the well known and trusted titration chemical reactions. The adaptation of these titration chemistries to rapid plate based absorbance methods for the sequential determination of hydrogen peroxide specifically and the total amount of peroxides present in solution are described. The results of these methods were compared to those of a standard titration and found to be in good agreement. Additionally, the utility of the developed method is demonstrated through the generation of degradation curves of both peracetic acid and hydrogen peroxide in a mixed solution.

  13. A high-throughput microtiter plate based method for the determination of peracetic acid and hydrogen peroxide.

    Science.gov (United States)

    Putt, Karson S; Pugh, Randall B

    2013-01-01

    Peracetic acid is gaining usage in numerous industries who have found a myriad of uses for its antimicrobial activity. However, rapid high throughput quantitation methods for peracetic acid and hydrogen peroxide are lacking. Herein, we describe the development of a high-throughput microtiter plate based assay based upon the well known and trusted titration chemical reactions. The adaptation of these titration chemistries to rapid plate based absorbance methods for the sequential determination of hydrogen peroxide specifically and the total amount of peroxides present in solution are described. The results of these methods were compared to those of a standard titration and found to be in good agreement. Additionally, the utility of the developed method is demonstrated through the generation of degradation curves of both peracetic acid and hydrogen peroxide in a mixed solution.

  14. Rapid identification and quantitation for oral bacteria based on short-end capillary electrophoresis.

    Science.gov (United States)

    Chen, Jin; Ni, Yi; Liu, Chenchen; Yamaguchi, Yoshinori; Chen, Qinmiao; Sekine, Shinichi; Zhu, Xifang; Dou, Xiaoming

    2016-11-01

    High-speed capillary electrophoresis (HSCE) is a promising technology applied in ultra-rapid and high-performance analysis of biomolecules (such as nucleic acids, protein). In present study, the short-end capillary electrophoresis coupled with one novel space domain internal standard method (SDIS) was employed for the rapid and simultaneous analysis of specific genes from three oral bacteria (Porphyromonas gingivalis (P.g), Treponema denticola (T.d) and Tannerela forsythia (T.f)). The reliability, reproducibility and accuracy properties of above mentioned SDIS method were investigated in detail. The results showed the target gene fragments of P.g, T.d and T.f could be precisely, fast identified and quantitated within 95s via present short-end CE system. The analyte concentration and the ratio of space domain signals (between target sample and internal standard sample) featured a well linear relationship calculated via SDIS method. And the correlation coefficients R(2) and detection limits for P.g, T.d, T.f genes were 0.9855, 0.9896, 0.9969 and 0.077, 0.114 and 0.098ng/μl, respectively.

  15. Sucrose quantitative and qualitative analysis from tastant mixtures based on Cu foam electrode and stochastic resonance.

    Science.gov (United States)

    Hui, Guohua; Zhang, Jianfeng; Li, Jian; Zheng, Le

    2016-04-15

    Quantitative and qualitative determination of sucrose from complex tastant mixtures using Cu foam electrode was investigated in this study. Cu foam was prepared and its three-dimensional (3-D) mesh structure was characterized by scanning electron microscopy (SEM). Cu foam was utilized as working electrode in three-electrode electrochemical system. Cyclic voltammetry (CV) scanning results exhibited the oxidation procedure of sucrose on Cu foam electrode. Amperometric i-t scanning results indicated that Cu foam electrode selectively responded to sucrose from four tastant mixtures with low limit of detection (LOD) of 35.34 μM, 49.85 μM, 45.89 μM, and 26.81 μM, respectively. The existence of quinine, NaCl, citric acid (CA) and their mixtures had no effect on sucrose detection. Furthermore, mixtures containing different tastants could be discriminated by non-linear double-layered cascaded series stochastic resonance (DCSSR) output signal-to-noise ratio (SNR) eigen peak parameters of CV measurement data. The proposed method provides a promising way for sweetener analysis of commercial food.

  16. 13C NMR Quantitative Study-Part 1: Relationships between the Conformation of Amino Acids, Peptide, Carboxylic Acids and Integration Intensity of 13C NMR

    Institute of Scientific and Technical Information of China (English)

    TIAN; JinPing

    2001-01-01

    In proton broad band decoupling 13C NMR, carbon atoms have different integration intensity because of NOE effects and their different relaxation time(T1), thus it makes a 13C NMR quantitative analyses very difficult. To acquire a 3C NMR quantitative analyses, a gated decoupling with suppressed NOE technology, i.e., an inversed gated decoupling pulse (IGDP), must be used. In IGDP relay time (tR) between two acquisition cycles must be more than 5T1, the time needed for a acquisition cycles is so long that makes the total 13C NMR quantitative analyses time much longer. For this reason, the 13C NMR quantitative analyses is paid less attention.  ……

  17. 13C NMR Quantitative Study-Part 1: Relationships between the Conformation of Amino Acids, Peptide, Carboxylic Acids and Integration Intensity of 13C NMR

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ In proton broad band decoupling 13C NMR, carbon atoms have different integration intensity because of NOE effects and their different relaxation time(T1), thus it makes a 13C NMR quantitative analyses very difficult. To acquire a 3C NMR quantitative analyses, a gated decoupling with suppressed NOE technology, i.e., an inversed gated decoupling pulse (IGDP), must be used. In IGDP relay time (tR) between two acquisition cycles must be more than 5T1, the time needed for a acquisition cycles is so long that makes the total 13C NMR quantitative analyses time much longer. For this reason, the 13C NMR quantitative analyses is paid less attention.

  18. Model for acid-base chemistry in nanoparticle growth (MABNAG

    Directory of Open Access Journals (Sweden)

    T. Yli-Juuti

    2013-03-01

    Full Text Available Climatic effects of newly-formed atmospheric secondary aerosol particles are to a large extent determined by their condensational growth rates. However, all the vapors condensing on atmospheric nanoparticles and growing them to climatically relevant sizes are not identified yet and the effects of particle phase processes on particle growth rates are poorly known. Besides sulfuric acid, organic compounds are known to contribute significantly to atmospheric nanoparticle growth. In this study a particle growth model MABNAG (Model for Acid-Base chemistry in NAnoparticle Growth was developed to study the effect of salt formation on nanoparticle growth, which has been proposed as a potential mechanism lowering the equilibrium vapor pressures of organic compounds through dissociation in the particle phase and thus preventing their evaporation. MABNAG is a model for monodisperse aqueous particles and it couples dynamics of condensation to particle phase chemistry. Non-zero equilibrium vapor pressures, with both size and composition dependence, are considered for condensation. The model was applied for atmospherically relevant systems with sulfuric acid, one organic acid, ammonia, one amine and water in the gas phase allowed to condense on 3–20 nm particles. The effect of dissociation of the organic acid was found to be small under ambient conditions typical for a boreal forest site, but considerable for base-rich environments (gas phase concentrations of about 1010 cm−3 for the sum of the bases. The contribution of the bases to particle mass decreased as particle size increased, except at very high gas phase concentrations of the bases. The relative importance of amine versus ammonia did not change significantly as a function of particle size. While our results give a reasonable first estimate on the maximum contribution of salt formation to nanoparticle growth, further studies on, e.g. the thermodynamic properties of the atmospheric organics

  19. Acid-base thermochemistry of gaseous oxygen and sulfur substituted amino acids (Ser, Thr, Cys, Met).

    Science.gov (United States)

    Riffet, Vanessa; Frison, Gilles; Bouchoux, Guy

    2011-11-07

    Acid-base thermochemistry of isolated amino acids containing oxygen or sulfur in their side chain (serine, threonine, cysteine and methionine) have been examined by quantum chemical computations. Density functional theory (DFT) was used, with B3LYP, B97-D and M06-2X functionals using the 6-31+G(d,p) basis set for geometry optimizations and the larger 6-311++G(3df,2p) basis set for energy computations. Composite methods CBS-QB3, G3B3, G4MP2 and G4 were applied to large sets of neutral, protonated and deprotonated conformers. Conformational analysis of these species, based on chemical approach and AMOEBA force field calculations, 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. It is observed that G4, G4MP2, G3B3, CBS-QB3 composite methods and M06-2X DFT lead to similar conformer energies. Thermochemical parameters have been computed using either the most stable conformers or equilibrium populations of conformers. Comparison of experimental and theoretical proton affinities and Δ(acid)H shows that the G4 method provides the better agreement with deviations of less than 1.5 kJ mol(-1). From this point of view, a set of evaluated thermochemical quantities for serine, threonine, cysteine and methionine may be proposed: PA = 912, 919, 903, 938; GB = 878, 886, 870, 899; Δ(acid)H = 1393, 1391, 1396, 1411; Δ(acid)G = 1363, 1362, 1367, 1382 kJ mol(-1). This study also confirms that a non-negligible ΔpS° is associated with protonation of methionine and that the most acidic hydrogen of cysteine in the gas phase is that of the SH group. In several instances new conformers were identified thus suggesting a re-examination of several IRMPD spectra.

  20. Enzymes for fatty acid-based hydrocarbon biosynthesis.

    Science.gov (United States)

    Herman, Nicolaus A; Zhang, Wenjun

    2016-12-01

    Surging energy consumption and environmental concerns have stimulated interest in the production of chemicals and fuels through sustainable and renewable approaches. Fatty acid-based hydrocarbons, such as alkanes and alkenes, are of particular interest to directly replace fossil fuels. Towards this effort, understanding of hydrocarbon-producing enzymes is the first indispensable step to bio-production of hydrocarbons. Here, we review recent advances in the discovery and mechanistic study of enzymes capable of converting fatty acid precursors into hydrocarbons, and provide perspectives on the future of this rapidly growing field. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. DVD technology-based molecular diagnosis platform: quantitative pregnancy test on a disc.

    Science.gov (United States)

    Li, Xiaochun; Weng, Samuel; Ge, Bixia; Yao, Zhihui; Yu, Hua-Zhong

    2014-05-21

    A diagnosis platform based entirely on DVD technology was developed for on-site quantitation of molecular analytes of interest, e.g., human chorionic gonadotropin (hCG) in urine samples ("quantitative pregnancy test on a disc"). An hCG-specific monoclonal antibody-binding assay prepared on a regular DVD-R was labeled with nanogold-streptavidin conjugates for signal enhancement with a customized silver-staining protocol. An unmodified, conventional computer optical drive was used for assay reading, and free disc-quality analysis software for data processing. The performance (sensitivity and selectivity) of this DVD assay is comparable to that of well-established colorimetric methods (determination of optical darkness ratios) and standard enzyme-linked immunosorbent assays (ELISA). As validated by examining its linear correlation with the ELISA results on the same set of samples, the DVD assay promises to be a low-cost, multiplex, point-of-care (POC) diagnostic tool for physicians and even for individuals at home, producing prompt results.

  2. A quantitative model of human DNA base excision repair. I. Mechanistic insights.

    Science.gov (United States)

    Sokhansanj, Bahrad A; Rodrigue, Garry R; Fitch, J Patrick; Wilson, David M

    2002-04-15

    Base excision repair (BER) is a multistep process involving the sequential activity of several proteins that cope with spontaneous and environmentally induced mutagenic and cytotoxic DNA damage. Quantitative kinetic data on single proteins of BER have been used here to develop a mathematical model of the BER pathway. This model was then employed to evaluate mechanistic issues and to determine the sensitivity of pathway throughput to altered enzyme kinetics. Notably, the model predicts considerably less pathway throughput than observed in experimental in vitro assays. This finding, in combination with the effects of pathway cooperativity on model throughput, supports the hypothesis of cooperation during abasic site repair and between the apurinic/apyrimidinic (AP) endonuclease, Ape1, and the 8-oxoguanine DNA glycosylase, Ogg1. The quantitative model also predicts that for 8-oxoguanine and hydrolytic AP site damage, short-patch Polbeta-mediated BER dominates, with minimal switching to the long-patch subpathway. Sensitivity analysis of the model indicates that the Polbeta-catalyzed reactions have the most control over pathway throughput, although other BER reactions contribute to pathway efficiency as well. The studies within represent a first step in a developing effort to create a predictive model for BER cellular capacity.

  3. Noninvasive and Quantitative Assessment of In Vivo Fetomaternal Interface Angiogenesis Using RGD-Based Fluorescence

    Directory of Open Access Journals (Sweden)

    M. Keramidas

    2014-01-01

    Full Text Available Angiogenesis is a key process for proper placental development and for the success of pregnancy. Although numerous in vitro methods have been developed for the assessment of this process, relatively few reliable in vivo methods are available to evaluate this activity throughout gestation. Here we report an in vivo technique that specifically measures placental neovascularization. The technique is based on the measurement of a fluorescent alpha v beta 3 (αvβ3 integrin-targeting molecule called Angiolone-Alexa-Fluor 700. The αvβ3 integrin is highly expressed by endothelial cells during the neovascularization and by trophoblast cells during their invasion of the maternal decidua. Angiolone was injected to gravid mice at 6.5 and 11.5 days post coitus (dpc. The fluorescence was analyzed one day later at 7.5 and 12.5 dpc, respectively. We demonstrated that (i Angiolone targets αvβ3 protein in the placenta with a strong specificity, (ii this technique is quantitative as the measurement was correlated to the increase of the placental size observed with increasing gestational age, and (iii information on the outcome is possible, as abnormal placentation could be detected early on during gestation. In conclusion, we report the validation of a new noninvasive and quantitative method to assess the placental angiogenic activity, in vivo.

  4. Quantitative method for measurement of the Goos-Hanchen effect based on source divergence considerations

    Science.gov (United States)

    Gray, Jeffrey F.; Puri, Ashok

    2007-06-01

    In this paper we report on a method for quantitative measurement and characterization of the Goos-Hanchen effect based upon the real world performance of optical sources. A numerical model of a nonideal plane wave is developed in terms of uniform divergence properties. This model is applied to the Goos-Hanchen shift equations to determine beam shift displacement characteristics, which provides quantitative estimates of finite shifts near critical angle. As a potential technique for carrying out a meaningful comparison with experiments, a classical method of edge detection is discussed. To this end a line spread Green’s function is defined which can be used to determine the effective transfer function of the near critical angle behavior of divergent plane waves. The process yields a distributed (blurred) output with a line spread function characteristic of the inverse square root nature of the Goos-Hanchen shift equation. A parameter of interest for measurement is given by the edge shift function. Modern imaging and image processing methods provide suitable techniques for exploiting the edge shift phenomena to attain refractive index sensitivities of the order of 10-6 , comparable with the recent results reported in the literature.

  5. Clinical study of quantitative diagnosis of early cervical cancer based on the classification of acetowhitening kinetics

    Science.gov (United States)

    Wu, Tao; Cheung, Tak-Hong; Yim, So-Fan; Qu, Jianan Y.

    2010-03-01

    A quantitative colposcopic imaging system for the diagnosis of early cervical cancer is evaluated in a clinical study. This imaging technology based on 3-D active stereo vision and motion tracking extracts diagnostic information from the kinetics of acetowhitening process measured from the cervix of human subjects in vivo. Acetowhitening kinetics measured from 137 cervical sites of 57 subjects are analyzed and classified using multivariate statistical algorithms. Cross-validation methods are used to evaluate the performance of the diagnostic algorithms. The results show that an algorithm for screening precancer produced 95% sensitivity (SE) and 96% specificity (SP) for discriminating normal and human papillomavirus (HPV)-infected tissues from cervical intraepithelial neoplasia (CIN) lesions. For a diagnostic algorithm, 91% SE and 90% SP are achieved for discriminating normal tissue, HPV infected tissue, and low-grade CIN lesions from high-grade CIN lesions. The results demonstrate that the quantitative colposcopic imaging system could provide objective screening and diagnostic information for early detection of cervical cancer.

  6. FDTD-based quantitative analysis of terahertz wave detection for multilayered structures.

    Science.gov (United States)

    Tu, Wanli; Zhong, Shuncong; Shen, Yaochun; Zhou, Qing; Yao, Ligang

    2014-10-01

    Experimental investigations have shown that terahertz pulsed imaging (TPI) is able to quantitatively characterize a range of multilayered media (e.g., biological issues, pharmaceutical tablet coatings, layered polymer composites, etc.). Advanced modeling of the interaction of terahertz radiation with a multilayered medium is required to enable the wide application of terahertz technology in a number of emerging fields, including nondestructive testing. Indeed, there have already been many theoretical analyses performed on the propagation of terahertz radiation in various multilayered media. However, to date, most of these studies used 1D or 2D models, and the dispersive nature of the dielectric layers was not considered or was simplified. In the present work, the theoretical framework of using terahertz waves for the quantitative characterization of multilayered media was established. A 3D model based on the finite difference time domain (FDTD) method is proposed. A batch of pharmaceutical tablets with a single coating layer of different coating thicknesses and different refractive indices was modeled. The reflected terahertz wave from such a sample was computed using the FDTD method, assuming that the incident terahertz wave is broadband, covering a frequency range up to 3.5 THz. The simulated results for all of the pharmaceutical-coated tablets considered were found to be in good agreement with the experimental results obtained using a commercial TPI system. In addition, we studied a three-layered medium to mimic the occurrence of defects in the sample.

  7. Quantitative serine protease assays based on formation of copper(II)-oligopeptide complexes.

    Science.gov (United States)

    Ding, Xiaokang; Yang, Kun-Lin

    2015-01-07

    A quantitative protease assay based on the formation of a copper-oligopeptide complex is developed. In this assay, when a tripeptide GGH fragment is cleaved from an oligopeptide chain by serine proteases, the tripeptide quickly forms a pink GGH/Cu(2+) complex whose concentration can be determined quantitatively by using UV-Vis spectroscopy. Therefore, activities of serine proteases can be determined from the formation rate of the GGH/Cu(2+) complex. This principle can be used to detect the presence of serine protease in a real-time manner, or measure proteolytic activities of serine protease cleaving different oligopeptide substrates. For example, by using this assay, we demonstrate that trypsin, a model serine protease, is able to cleave two oligopeptides GGGGKGGH () and GGGGRGGH (). However, the specificity constant (kcat/Km) for is higher than that of (6.4 × 10(3) mM(-1) min(-1)vs. 1.3 × 10(3) mM(-1) min(-1)). This result shows that trypsin is more specific toward arginine (R) than lysine (K) in the oligopeptide sequence.

  8. Quantitative characterization of the carbon/carbon composites components based on video of polarized light microscope.

    Science.gov (United States)

    Li, Yixian; Qi, Lehua; Song, Yongshan; Chao, Xujiang

    2017-02-13

    The components of carbon/carbon (C/C) composites have significant influence on the thermal and mechanical properties, so a quantitative characterization of component is necessary to study the microstructure of C/C composites, and further to improve the macroscopic properties of C/C composites. Considering the extinction crosses of the pyrocarbon matrix have significant moving features, the polarized light microscope (PLM) video is used to characterize C/C composites quantitatively because it contains sufficiently dynamic and structure information. Then the optical flow method is introduced to compute the optical flow field between the adjacent frames, and segment the components of C/C composites from PLM image by image processing. Meanwhile the matrix with different textures is re-segmented by the length difference of motion vectors, and then the component fraction of each component and extinction angle of pyrocarbon matrix are calculated directly. Finally, the C/C composites are successfully characterized from three aspects of carbon fiber, pyrocarbon, and pores by a series of image processing operators based on PLM video, and the errors of component fractions are less than 15%.

  9. An automatic framework for quantitative validation of voxel based morphometry measures of anatomical brain asymmetry.

    Science.gov (United States)

    Pepe, Antonietta; Dinov, Ivo; Tohka, Jussi

    2014-10-15

    The study of anatomical brain asymmetries has been a topic of great interest in the neuroimaging community in the past decades. However, the accuracy of brain asymmetry measurements has been rarely investigated. In this study, we propose a fully automatic methodology for the quantitative validation of brain tissue asymmetries as measured by Voxel Based Morphometry (VBM) from structural magnetic resonance (MR) images. Starting from a real MR image, the methodology generates simulated 3D MR images with a known and realistic pattern of inter-hemispheric asymmetry that models the left-occipital right-frontal petalia of a normal brain and the related rightward bending of the inter-hemispheric fissure. As an example, we generated a dataset of 64 simulated MR images and applied this dataset for the quantitative validation of optimized VBM measures of asymmetries in brain tissue composition. Our results suggested that VBM analysis strongly depended on the spatial normalization of the individual brain images, the selected template space, and the amount of spatial smoothing applied. The most accurate asymmetry detections were achieved by 9-degrees of freedom registration to the symmetrical template space with 4 to 8mm spatial smoothing.

  10. A Compressed Sensing-Based Wearable Sensor Network for Quantitative Assessment of Stroke Patients

    Directory of Open Access Journals (Sweden)

    Lei Yu

    2016-02-01

    Full Text Available Clinical rehabilitation assessment is an important part of the therapy process because it is the premise for prescribing suitable rehabilitation interventions. However, the commonly used assessment scales have the following two drawbacks: (1 they are susceptible to subjective factors; (2 they only have several rating levels and are influenced by a ceiling effect, making it impossible to exactly detect any further improvement in the movement. Meanwhile, energy constraints are a primary design consideration in wearable sensor network systems since they are often battery-operated. Traditionally, for wearable sensor network systems that follow the Shannon/Nyquist sampling theorem, there are many data that need to be sampled and transmitted. This paper proposes a novel wearable sensor network system to monitor and quantitatively assess the upper limb motion function, based on compressed sensing technology. With the sparse representation model, less data is transmitted to the computer than with traditional systems. The experimental results show that the accelerometer signals of Bobath handshake and shoulder touch exercises can be compressed, and the length of the compressed signal is less than 1/3 of the raw signal length. More importantly, the reconstruction errors have no influence on the predictive accuracy of the Brunnstrom stage classification model. It also indicated that the proposed system can not only reduce the amount of data during the sampling and transmission processes, but also, the reconstructed accelerometer signals can be used for quantitative assessment without any loss of useful information.

  11. A Compressed Sensing-Based Wearable Sensor Network for Quantitative Assessment of Stroke Patients

    Science.gov (United States)

    Yu, Lei; Xiong, Daxi; Guo, Liquan; Wang, Jiping

    2016-01-01

    Clinical rehabilitation assessment is an important part of the therapy process because it is the premise for prescribing suitable rehabilitation interventions. However, the commonly used assessment scales have the following two drawbacks: (1) they are susceptible to subjective factors; (2) they only have several rating levels and are influenced by a ceiling effect, making it impossible to exactly detect any further improvement in the movement. Meanwhile, energy constraints are a primary design consideration in wearable sensor network systems since they are often battery-operated. Traditionally, for wearable sensor network systems that follow the Shannon/Nyquist sampling theorem, there are many data that need to be sampled and transmitted. This paper proposes a novel wearable sensor network system to monitor and quantitatively assess the upper limb motion function, based on compressed sensing technology. With the sparse representation model, less data is transmitted to the computer than with traditional systems. The experimental results show that the accelerometer signals of Bobath handshake and shoulder touch exercises can be compressed, and the length of the compressed signal is less than 1/3 of the raw signal length. More importantly, the reconstruction errors have no influence on the predictive accuracy of the Brunnstrom stage classification model. It also indicated that the proposed system can not only reduce the amount of data during the sampling and transmission processes, but also, the reconstructed accelerometer signals can be used for quantitative assessment without any loss of useful information. PMID:26861337

  12. A Compressed Sensing-Based Wearable Sensor Network for Quantitative Assessment of Stroke Patients.

    Science.gov (United States)

    Yu, Lei; Xiong, Daxi; Guo, Liquan; Wang, Jiping

    2016-02-05

    Clinical rehabilitation assessment is an important part of the therapy process because it is the premise for prescribing suitable rehabilitation interventions. However, the commonly used assessment scales have the following two drawbacks: (1) they are susceptible to subjective factors; (2) they only have several rating levels and are influenced by a ceiling effect, making it impossible to exactly detect any further improvement in the movement. Meanwhile, energy constraints are a primary design consideration in wearable sensor network systems since they are often battery-operated. Traditionally, for wearable sensor network systems that follow the Shannon/Nyquist sampling theorem, there are many data that need to be sampled and transmitted. This paper proposes a novel wearable sensor network system to monitor and quantitatively assess the upper limb motion function, based on compressed sensing technology. With the sparse representation model, less data is transmitted to the computer than with traditional systems. The experimental results show that the accelerometer signals of Bobath handshake and shoulder touch exercises can be compressed, and the length of the compressed signal is less than 1/3 of the raw signal length. More importantly, the reconstruction errors have no influence on the predictive accuracy of the Brunnstrom stage classification model. It also indicated that the proposed system can not only reduce the amount of data during the sampling and transmission processes, but also, the reconstructed accelerometer signals can be used for quantitative assessment without any loss of useful information.

  13. Two approaches to improving mental health care: positivist/quantitative versus skill-based/qualitative.

    Science.gov (United States)

    Luchins, Daniel

    2012-01-01

    The quality improvement model currently used in medicine and mental health was adopted from industry, where it developed out of early 20th-century efforts to apply a positivist/quantitative agenda to improving manufacturing. This article questions the application of this model to mental health care. It argues that (1) developing "operational definitions" for something as value-laden as "quality" risks conflating two realms, what we measure with what we value; (2) when measurements that are tied to individuals are aggregated to establish benchmarks and goals, unwarranted mathematical assumptions are made; (3) choosing clinical outcomes is problematic; (4) there is little relationship between process measures and clinical outcomes; and (5) since changes in quality indices do not relate to improved clinical care, management's reliance on such indices provides an illusory sense of control. An alternative model is the older, skill-based/qualitative approach to knowing, which relies on "implicit/ expert" knowledge. These two approaches offer a series of contrasts: quality versus excellence, competence versus expertise, management versus leadership, extrinsic versus intrinsic rewards. The article concludes that we need not totally dispense with the current quality improvement model, but rather should balance quantitative efforts with the older qualitative approach in a mixed methods model.

  14. A method to prioritize quantitative traits and individuals for sequencing in family-based studies.

    Directory of Open Access Journals (Sweden)

    Kaanan P Shah

    Full Text Available Owing to recent advances in DNA sequencing, it is now technically feasible to evaluate the contribution of rare variation to complex traits and diseases. However, it is still cost prohibitive to sequence the whole genome (or exome of all individuals in each study. For quantitative traits, one strategy to reduce cost is to sequence individuals in the tails of the trait distribution. However, the next challenge becomes how to prioritize traits and individuals for sequencing since individuals are often characterized for dozens of medically relevant traits. In this article, we describe a new method, the Rare Variant Kinship Test (RVKT, which leverages relationship information in family-based studies to identify quantitative traits that are likely influenced by rare variants. Conditional on nuclear families and extended pedigrees, we evaluate the power of the RVKT via simulation. Not unexpectedly, the power of our method depends strongly on effect size, and to a lesser extent, on the frequency of the rare variant and the number and type of relationships in the sample. As an illustration, we also apply our method to data from two genetic studies in the Old Order Amish, a founder population with extensive genealogical records. Remarkably, we implicate the presence of a rare variant that lowers fasting triglyceride levels in the Heredity and Phenotype Intervention (HAPI Heart study (p = 0.044, consistent with the presence of a previously identified null mutation in the APOC3 gene that lowers fasting triglyceride levels in HAPI Heart study participants.

  15. Qualitative and quantitative determination of seven triterpene acids in Eriobotrya japonica Lindl. by high-performance liquid chromatography with photodiode array detection and mass spectrometry.

    Science.gov (United States)

    Li, Er-Na; Luo, Jian-Guang; Kong, Ling-Yi

    2009-01-01

    The leaves of Eriobotrya japonica are used for the treatment of diabetes mellitus, chronic bronchitis, coughs and skin diseases. No method is currently available, however, by which to assess the quality of the crude herb on the basis of the quantitative profile of the main bioactive triterpene acids present. To develop a simple and accurate HPLC-UV (photodiode array detection) method for the simultaneous quantification of seven triterpene acids in the leaves of E. japonica. Separations were performed on an Ultimate XB-C18 column by gradient elution using methanol:formic acid. Analytes were identified by HPLC coupled with electrospray ionisation mass spectrometry experiments. The quantitative HPLC-UV method was validated for linearity, precision, accuracy, and limits of detection and quantification. Calibration curves presented good linear regression (r > 0.9992) within test ranges. The precision and accuracy of the method were acceptable with overall intra-day and inter-day variations of 1.35-3.30 and 1.98-4.43%, respectively, and overall recoveries of 95.60-102.67% for the seven compounds analysed. The method was successfully applied to the quantification of seven triterpene acids in eleven samples of E. japonica collected from different provinces of China. The developed assay could be considered as a suitable quality control method for E. japonica.

  16. 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.

  17. Quantitative measurement of hepatic fibrosis with gadoxetic acid-enhanced magnetic resonance imaging in patients with chronic hepatitis B infection: A comparative study on aspartate aminotransferase to platelet ratio index and fibrosis-4 index

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Guy Mok; Kim, Youe Ree; Cho, Eun Young; Lee, Young Hwan; Yoon, Kwon Ha [Wonkwang University School of Medicine, Iksan (Korea, Republic of); Ryu, Jong Hyun; Kim, Tae Hoon [Imaging Science Research Center, Wonkwang University, Iksan (Korea, Republic of)

    2017-06-15

    To quantitatively measure hepatic fibrosis on gadoxetic acid-enhanced magnetic resonance (MR) in chronic hepatitis B (CHB) patients and identify the correlations with aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis-4 index (FIB-4) values. This study on gadoxetic acid-enhanced 3T MR imaging included 81 patients with CHB infection. To quantitatively measure hepatic fibrosis, MR images were analyzed with an aim to identify inhomogeneous signal intensities calculated from a coefficient of variation (CV) map in the liver parenchyma. We also carried out a comparative analysis between APRI and FIB-4 based on metaregression results. The diagnostic performance of the CV map was evaluated using a receiver-operating characteristic (ROC) curve. In the MR images, the mean CV values in control, groups I, II, and III based on APRI were 4.08 ± 0.92, 4.24 ± 0.80, 5.64 ± 1.11, and 5.73 ± 1.28, respectively (p < 0.001). In CHB patients grouped by FIB-4, the mean CV values of groups A, B, and C were 4.22 ± 0.95, 5.40 ± 1.19, and 5.71 ± 1.17, respectively (p < 0.001). The mean CV values correlated well with APRI (r = 0.392, p < 0.001) and FIB-4 (r = 0.294, p < 0.001). In significant fibrosis group, ROC curve analysis yielded an area under the curve of 0.875 using APRI and 0.831 using FIB-4 in HB, respectively. Gadoxetic acid-enhanced MR imaging for calculating a CV map showed moderate correlation with APRI and FIB-4 values and could be employed to quantitatively measure hepatic fibrosis in patients with CHB.

  18. Quantitative, small-scale, fluorophore-assisted carbohydrate electrophoresis implemented on a capillary electrophoresis-based DNA sequence analyzer.

    Science.gov (United States)

    Murray, Sarah; McKenzie, Marian; Butler, Ruth; Baldwin, Samantha; Sutton, Kevin; Batey, Ian; Timmerman-Vaughan, Gail M

    2011-06-15

    Fluorophore-assisted carbohydrate electrophoresis (FACE) is an analytical method for characterizing carbohydrate chain length that has been applied to neutral, charged, and N-linked oligosaccharides and that has been implemented using diverse separation platforms, including polyacrylamide gel electrophoresis and capillary electrophoresis. In this article, we describe three substantial improvements to FACE: (i) reducing the amount of starch and APTS required in labeling reactions and systematically analyzing the effect of altering the starch and 8-amino-1,3,6-pyrenetrisulfonic acid (APTS) concentrations on the reproducibility of the FACE peak area distributions; (ii) implementing FACE on a multiple capillary DNA sequencer (an ABI 3130xl), enabling higher throughput than is possible on other separation platforms; and (iii) developing a protocol for producing quantitative output of peak heights and areas using genetic marker analysis software. The results of a designed experiment to determine the effect of decreasing both the starch and fluorophore concentrations on the sensitivity and reproducibility of FACE electrophoregrams are presented. Analysis of the peak area distributions of the FACE electrophoregrams identified the labeling reaction conditions that resulted in the smallest variances in the peak area distributions while retaining strong fluorescence signals from the capillary-based DNA sequencer.

  19. Preparation and characterization of biomass carbon-based solid acid catalyst for the esterification of oleic acid with methanol.

    Science.gov (United States)

    Liu, Tiantian; Li, Zhilong; Li, Wei; Shi, Congjiao; Wang, Yun

    2013-04-01

    A solid acid catalyst, prepared by sulfonating carbonized corn straw, was proved to be an efficient and environmental benign catalyst for the esterification of oleic acid and methanol. Various synthetic parameters, such as carbonization temperature and time were systematically examined. It was found that the catalyst exhibited the highest acid density of 2.64 mmol/g by NaOH titration. A quantitative yield (98%) of ester was achieved, using the most active sulfonated catalyst at 333 K with a 7 wt.% catalyst/oleic acid ratio for 4h, at a 7:1 M ratio of methanol/oleic acid, while the commercial available Amberlyst-15 only gave 85% yield under the same reaction condition.

  20. Difference between Extra- and IntracellularT1Values of Carboxylic Acids Affects the Quantitative Analysis of Cellular Kinetics by Hyperpolarized NMR

    DEFF Research Database (Denmark)

    Karlsson, Magnus; Jensen, Pernille Rose; Ardenkjær-Larsen, Jan Henrik;

    2016-01-01

    Incomplete knowledge of the longitudinal relaxationtime constant (T1) leads to incorrect assumptions in quantita-tive kinetic models of cellular systems, studied by hyper-polarized real-time NMR. Using an assay that measures theintracellular signal of small carboxylic acids in living cells......, theintracellular T1of the carboxylic acid moiety of acetate, keto-isocaproate, pyruvate, and butyrate was determined. Theintracellular T1is shown to be up to four-fold shorter thanthe extracellular T1. Such a large difference in T1valuesbetween the inside and the outside of the cell has significantinfluence...... on the quantification of intracellular metabolicactivity. It is expected that the significantly shorter T1valueof the carboxylic moieties inside cells is a result of macro-molecular crowding. An artificial cytosol has been preparedand applied to predict the T1of other carboxylic acids. Wedemonstrate the value...