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Sample records for ph probe test

  1. Gastroesophageal reflux: the acid test, scintigraphy or the pH probe

    International Nuclear Information System (INIS)

    Seibert, J.J.; Byrne, W.J.; Euler, A.R.; Latture, T.; Leach, M.; Campbell, M.

    1983-01-01

    The best established technique for diagnosing gastroesophageal reflux in children is the 24 hr esophageal pH probe test. No simultaneous comparison of this technique with radionuclide scans has been reported. Therefore, simultaneous 1 hr pH monitoring and gastroesophageal scintigraphy were performed in 49 infants and children with suspected gastroesophageal reflux. Forty-seven of these patients also were later monitored by the 24 hr pH probe test. Upper gastrointestinal series were performed on all patients. All patients with a positive 1 hr pH monitoring also had positive simultaneous scintigraphy. All patients with positive scintigraphy and pH probe monitoring also had a positive upper gastrointestinal series for reflux. The sensitivity of gastroesophageal scintigraphy, when compared to the 24 hr probe as a standard, was 79%; its specificity was 93%. The sensitivity of the upper gastrointestinal series was 86%, when compared to the 24 hr pH probe test. However, its specificity was only 21%

  2. Fluorescent probes and nanoparticles for intracellular sensing of pH values

    Science.gov (United States)

    Shi, Wen; Li, Xiaohua; Ma, Huimin

    2014-12-01

    Intracellular pH regulates a number of cell metabolism processes and its sensing is thus of great importance for cell studies. Among various methods, fluorescent probes have been widely used for sensing intracellular pH values because of their high sensitivity and spatiotemporal resolution capability. In this article, the development of fluorescent probes with good practicability in sensing intracellular pH values and pH variation during 2009 - 2014 is reviewed. These fluorescence probes are divided into two kinds: small molecules and nanoparticles. Photophysical properties, advantages/disadvantages and applications of the two kinds of probes are discussed in detail.

  3. A new fluorescent pH probe for extremely acidic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yu [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Jiang, Zheng [School of Life Science, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Xiao, Yu [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Bi, Fu-Zhen [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Miao, Jun-Ying, E-mail: miaojy@sdu.edu.cn [School of Life Science, Shandong University, Jinan 250100 (China); Zhao, Bao-Xiang, E-mail: bxzhao@sdu.edu.cn [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2014-04-01

    A new coumarin-based fluorescent probe can detect highly acidic conditions in both solution and bacteria with high selectivity and sensitivity. Highlights: • A new fluorescence probe for very low pH was synthesized and characterized. • The probe can monitor pH in solution and bacteria. • The two-step protonation of N atoms of the probe leads to fluorescence quenching. Abstract: A novel turn-off fluorescent probe based on coumarin and imidazole moiety for extremely acidic conditions was designed and developed. The probe with pKa = 2.1 is able to respond to very low pH value (below 3.5) with high sensitivity relying on fluorescence quenching at 460 nm in fluorescence spectra or the ratios of absorbance maximum at 380 nm to that at 450 nm in UV–vis spectra. It can quantitatively detect pH value based on equilibrium equation, pH = pKa -log[(Ix - Ib)/(Ia - Ix)]. It had very short response time that was less than 1 min, good reversibility and nearly no interference from common metal ions. Moreover, using ¹H NMR analysis and theoretical calculation of molecular orbital, we verified that a two-step protonation process of two N atoms of the probe leaded to photoinduced electron transfer (PET), which was actually the mechanism of the fluorescence quenching phenomenon under strongly acidic conditions. Furthermore, the probe was also applied to imaging strong acidity in bacteria, E.coli and had good effect. This work illustrates that the new probe could be a practical and ideal pH indicator for strongly acidic conditions with good biological significance.

  4. Fluorescent probes and nanoparticles for intracellular sensing of pH values

    International Nuclear Information System (INIS)

    Shi, Wen; Li, Xiaohua; Ma, Huimin

    2014-01-01

    Intracellular pH regulates a number of cell metabolism processes and its sensing is thus of great importance for cell studies. Among various methods, fluorescent probes have been widely used for sensing intracellular pH values because of their high sensitivity and spatiotemporal resolution capability. In this article, the development of fluorescent probes with good practicability in sensing intracellular pH values and pH variation during 2009 − 2014 is reviewed. These fluorescence probes are divided into two kinds: small molecules and nanoparticles. Photophysical properties, advantages/disadvantages and applications of the two kinds of probes are discussed in detail. (topical review)

  5. A novel acidic pH fluorescent probe based on a benzothiazole derivative

    Science.gov (United States)

    Ma, Qiujuan; Li, Xian; Feng, Suxiang; Liang, Beibei; Zhou, Tiqiang; Xu, Min; Ma, Zhuoyi

    2017-04-01

    A novel acidic pH fluorescent probe 1 based on a benzothiazole derivative has been designed, synthesized and developed. The linear response range covers the acidic pH range from 3.44 to 6.46, which is valuable for pH researches in acidic environment. The evaluated pKa value of the probe 1 is 4.23. The fluorescence enhancement of the studied probe 1 with an increase in hydrogen ions concentration is based on the hindering of enhanced photo-induced electron transfer (PET) process. Moreover, the pH sensor possesses a highly selective response to H+ in the presence of metal ions, anions and other bioactive small molecules which would be interfere with its fluorescent pH response. Furthermore, the probe 1 responds to acidic pH with short response time that was less than 1 min. The probe 1 has been successfully applied to confocal fluorescence imaging in live HeLa cells and can selectively stain lysosomes. All of such good properties prove it can be used to monitoring pH fluctuations in acidic environment with high sensitivity, pH dependence and short response time.

  6. An easily Prepared Fluorescent pH Probe Based on Dansyl.

    Science.gov (United States)

    Sha, Chunming; Chen, Yuhua; Chen, Yufen; Xu, Dongmei

    2016-09-01

    A novel fluorescent pH probe from dansyl chloride and thiosemicarbazide was easily prepared and fully characterized by (1)H NMR, (13)C NMR, LC-MS, Infrared spectra and elemental analysis. The probe exhibited high selectivity and sensitivity to H(+) with a pK a value of 4.98. The fluorescence intensity at 510 nm quenched 99.5 % when the pH dropped from 10.88 to 1.98. In addition, the dansyl-based probe could respond quickly and reversibly to the pH variation and various common metal ions showed negligible interference. The recognition could be ascribed to the intramolecular charge transfer caused by the protonation of the nitrogen in the dimethylamino group.

  7. A new fluorescent pH probe for imaging lysosomes in living cells.

    Science.gov (United States)

    Lv, Hong-Shui; Huang, Shu-Ya; Xu, Yu; Dai, Xi; Miao, Jun-Ying; Zhao, Bao-Xiang

    2014-01-15

    A new rhodamine B-based pH fluorescent probe has been synthesized and characterized. The probe responds to acidic pH with short response time, high selectivity and sensitivity, and exhibits a more than 20-fold increase in fluorescence intensity within the pH range of 7.5-4.1 with the pKa value of 5.72, which is valuable to study acidic organelles in living cells. Also, it has been successfully applied to HeLa cells, for its low cytotoxicity, brilliant photostability, good membrane permeability and no 'alkalizing effect' on lysosomes. The results demonstrate that this probe is a lysosome-specific probe, which can selectively stain lysosomes and monitor lysosomal pH changes in living cells. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. A cell-surface-anchored ratiometric fluorescent probe for extracellular pH sensing.

    Science.gov (United States)

    Ke, Guoliang; Zhu, Zhi; Wang, Wei; Zou, Yuan; Guan, Zhichao; Jia, Shasha; Zhang, Huimin; Wu, Xuemeng; Yang, Chaoyong James

    2014-09-10

    Accurate sensing of the extracellular pH is a very important yet challenging task in biological and clinical applications. This paper describes the development of an amphiphilic lipid-DNA molecule as a simple yet useful cell-surface-anchored ratiometric fluorescent probe for extracellular pH sensing. The lipid-DNA probe, which consists of a hydrophobic diacyllipid tail and a hydrophilic DNA strand, is modified with two fluorescent dyes; one is pH-sensitive as pH indicator and the other is pH-insensitive as an internal reference. The lipid-DNA probe showed sensitive and reversible response to pH change in the range of 6.0-8.0, which is suitable for most extracellular studies. In addition, based on simple hydrophobic interactions with the cell membrane, the lipid-DNA probe can be easily anchored on the cell surface with negligible cytotoxicity, excellent stability, and unique ratiometric readout, thus ensuring its accurate sensing of extracellular pH. Finally, this lipid-DNA-based ratiometric pH indicator was successfully used for extracellular pH sensing of cells in 3D culture environment, demonstrating the potential applications of the sensor in biological and medical studies.

  9. Dual-Modal Colorimetric/Fluorescence Molecular Probe for Ratiometric Sensing of pH and Its Application.

    Science.gov (United States)

    Wu, Luling; Li, Xiaolin; Huang, Chusen; Jia, Nengqin

    2016-08-16

    As traditional pH meters cannot work well for minute regions (such as subcellular organelles) and in harsh media, molecular pH-sensitive devices for monitoring pH changes in diverse local heterogeneous environments are urgently needed. Here, we report a new dual-modal colorimetric/fluorescence merocyanine-based molecular probe (CPH) for ratiometric sensing of pH. Compared with previously reported pH probes, CPH bearing the benzyl group at the nitrogen position of the indolium group and the phenol, which is used as the acceptor for proton, could respond to pH changes immediately through both the ratiometric fluorescence signal readout and naked-eye colorimetric observation. The sensing process was highly stable and reversible. Most importantly, the suitable pKa value (6.44) allows CPH to presumably accumulate in lysosomes and become a lysosome-target fluorescent probe. By using CPH, the intralysosomal pH fluctuation stimulated by antimalaria drug chloroquine was successfully tracked in live cells through the ratiometric fluorescence images. Additionally, CPH could be immobilized on test papers, which exhibited a rapid and reversible colorimetric response to acid/base vapor through the naked-eye colorimetric analysis. This proof-of-concept study presents the potential application of CPH as a molecular tool for monitoring intralysosomal pH fluctuation in live cells, as well as paves the way for developing the economic, reusable, and fast-response optical pH meters for colorimetric sensing acid/base vapor with direct naked-eye observation.

  10. The clinical value of pharyngeal pH monitoring using a double-probe, triple-sensor catheter in patients with laryngopharyngeal reflux.

    Science.gov (United States)

    Muderris, Togay; Gokcan, M Kursat; Yorulmaz, Irfan

    2009-02-01

    To determine the clinical value of pharyngeal pH monitoring for the diagnosis of laryngopharyngeal reflux (LPR) by using a double-probe, triple-sensor catheter in patients with symptoms of LPR. Prospective review of pH values recorded at the pharyngeal sensor, with the sensor placed in the proximal esophagus in patients with suspected LPR. Tertiary care university hospital. Thirty-three consecutive patients with symptoms of LPR. A pH test result was considered abnormal if a single reflux episode was detected in the hypopharynx and if, in the proximal esophagus, the total percentage of time the pH value was below 4 was 1.0% or higher. Data obtained from sensors were compared to determine the validity of pharyngeal sensor. Correlation between patients' reflux finding scores, reflux finding indexes, and reflux episodes were analyzed. Of 33 patients, 17 had more than 1 reflux episode detected by the pharyngeal sensor and 19 had pathological reflux detected by the proximal esophageal sensor. Four patients who had pharyngeal reflux had a normal esophageal acid exposure time, and 6 patients who had pathological reflux detected by the proximal esophageal sensor did not experienced any pharyngeal reflux episode. Four patients would have had a false-negative test result and 6 subjects would have had a false-positive test result if a hypopharyngeal pH sensor was not implemented. The adjustable, bifurcated, triple-sensor pH probe allows identifying true hypopharyngeal reflux episodes. If single-probe, double-sensor pH monitoring is to be performed, the proximal probe should be placed in the pharynx, not in the upper esophagus.

  11. A single pH fluorescent probe for biosensing and imaging of extreme acidity and extreme alkalinity.

    Science.gov (United States)

    Chao, Jian-Bin; Wang, Hui-Juan; Zhang, Yong-Bin; Li, Zhi-Qing; Liu, Yu-Hong; Huo, Fang-Jun; Yin, Cai-Xia; Shi, Ya-Wei; Wang, Juan-Juan

    2017-07-04

    A simple tailor-made pH fluorescent probe 2-benzothiazole (N-ethylcarbazole-3-yl) hydrazone (Probe) is facilely synthesized by the condensation reaction of 2-hydrazinobenzothiazole with N-ethylcarbazole-3-formaldehyde, which is a useful fluorescent probe for monitoring extremely acidic and alkaline pH, quantitatively. The pH titrations indicate that Probe displays a remarkable emission enhancement with a pK a of 2.73 and responds linearly to minor pH fluctuations within the extremely acidic range of 2.21-3.30. Interestingly, Probe also exhibits strong pH-dependent characteristics with pK a 11.28 and linear response to extreme-alkalinity range of 10.41-12.43. In addition, Probe shows a large Stokes shift of 84 nm under extremely acidic and alkaline conditions, high selectivity, excellent sensitivity, good water-solubility and fine stability, all of which are favorable for intracellular pH imaging. The probe is further successfully applied to image extremely acidic and alkaline pH values fluctuations in E. coli cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Colorimetric and Fluorescent Bimodal Ratiometric Probes for pH Sensing of Living Cells.

    Science.gov (United States)

    Liu, Yuan-Yuan; Wu, Ming; Zhu, Li-Na; Feng, Xi-Zeng; Kong, De-Ming

    2015-06-01

    pH measurement is widely used in many fields. Ratiometric pH sensing is an important way to improve the detection accuracy. Herein, five water-soluble cationic porphyrin derivatives were synthesized and their optical property changes with pH value were investigated. Their pH-dependent assembly/disassembly behaviors caused significant changes in both absorption and fluorescence spectra, thus making them promising bimodal ratiometric probes for both colorimetric and fluorescent pH sensing. Different substituent identity and position confer these probes with different sensitive pH-sensing ranges, and the substituent position gives a larger effect. By selecting different porphyrins, different signal intensity ratios and different fluorescence excitation wavelengths, sensitive pH sensing can be achieved in the range of 2.1-8.0. Having demonstrated the excellent reversibility, good accuracy and low cytotoxicity of the probes, they were successfully applied in pH sensing inside living cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A Novel Water-soluble Ratiometric Fluorescent Probe Based on FRET for Sensing Lysosomal pH.

    Science.gov (United States)

    Song, Guang-Jie; Bai, Su-Yun; Luo, Jing; Cao, Xiao-Qun; Zhao, Bao-Xiang

    2016-11-01

    A new ratiometric fluorescent probe based on Förster resonance energy transfer (FRET) for sensing lysosomal pH has been developed. The probe (RMPM) was composed of imidazo[1,5-α]pyridine quaternary ammonium salt fluorophore as the FRET donor and the rhodamine moiety as the FRET acceptor. It's the first time to report that imidazo[1,5-α]pyridine quaternary ammonium salt acts as the FRET donor. The ratio of fluorescence intensity of the probe at two wavelengths (I 424 /I 581 ) changed significantly and responded linearly toward minor pH changes in the range of 5.4-6.6. It should be noted that it's rare to report that a ratiometric pH probe could detect so weak acidic pH with pKa = 6.31. In addition, probe RMPM exhibited excellent water-solubility, fast-response, all-right selectivity and brilliant reversibility. Moreover, RMPM has been successfully applied to sensing lysosomal pH in HeLa cells and has low cytotoxicity.

  14. An intramolecular charge transfer process based fluorescent probe for monitoring subtle pH fluctuation in living cells.

    Science.gov (United States)

    Sun, Mingtai; Du, Libo; Yu, Huan; Zhang, Kui; Liu, Yang; Wang, Suhua

    2017-01-01

    It is crucial to monitor intracellular pH values and their fluctuation since the organelles of cells have different pH distribution. Herein we construct a new small molecule fluorescent probe HBT-O for monitoring the subtle pH values within the scope of neutral to acid in living cells. The probe exhibited good water solubility, a marked turquoise to olivine emission color change in response to pH, and tremendous fluorescence hypochromatic shift of ∼50nm (1718cm -1 ) as well as the increased fluorescence intensity when the pH value changed from neutral to acid. Thus, the probe HBT-O can distinguish the subtle changes in the range of normal pH values from neutral to acid with significant fluorescence changes. These properties can be attributed to the intramolecular charge transfer (ICT) process of the probe upon protonation in buffer solutions at varied pH values. Moreover, the probe was reversible and nearly non-toxic for living cells. Then the probe was successfully used to detect pH fluctuation in living cells by exhibiting different fluorescence colors and intensity. These findings demonstrate that the probe will find useful applications in biology and biomedical research. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. A NBD-based simple but effective fluorescent pH probe for imaging of lysosomes in living cells

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xiang-Jian [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Chen, Li-Na [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Zhang, Xuan [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Liu, Jin-Ting [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Chen, Ming-Yu [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Wu, Qiu-Rong [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Miao, Jun-Ying, E-mail: miaojy@sdu.edu.cn [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Zhao, Bao-Xiang, E-mail: bxzhao@sdu.edu.cn [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2016-05-12

    NBDlyso with lysosome-locating morpholine moiety has been developed as a high selective and sensitive fluorescent pH probe. This probe can respond to acidic pH (2.0–7.0) in a short time (less than 1 min) and not almost change after continuously illuminated for an extended period by ultraviolet light. The fluorescence intensity of NBDlyso enhanced 100-fold in acidic solution, with very good linear relationship (R{sup 2} = 0.996). The pK{sub a} of probe NBDlyso is 4.10. Therefore, NBDlyso was used to detect lysosomal pH changes successfully. Besides, X-ray crystallography was used to verify the structure of NBDlyso, and the recognition mechanism involving photo-induced electron transfer was interpreted theoretically by means of DFT and TDDFT calculations skillfully when NBDlyso comes into play under the acidic condition. This probe showed good ability to sense pH change in living cell image. - Highlights: • An effective NBD-based fluorescent pH probe was developed. • The sensing mechanism was interpreted by theoretical calculation. • This probe was successfully used to monitor lysosoml pH changes in Hela cells.

  16. A NBD-based simple but effective fluorescent pH probe for imaging of lysosomes in living cells

    International Nuclear Information System (INIS)

    Cao, Xiang-Jian; Chen, Li-Na; Zhang, Xuan; Liu, Jin-Ting; Chen, Ming-Yu; Wu, Qiu-Rong; Miao, Jun-Ying; Zhao, Bao-Xiang

    2016-01-01

    NBDlyso with lysosome-locating morpholine moiety has been developed as a high selective and sensitive fluorescent pH probe. This probe can respond to acidic pH (2.0–7.0) in a short time (less than 1 min) and not almost change after continuously illuminated for an extended period by ultraviolet light. The fluorescence intensity of NBDlyso enhanced 100-fold in acidic solution, with very good linear relationship (R"2 = 0.996). The pK_a of probe NBDlyso is 4.10. Therefore, NBDlyso was used to detect lysosomal pH changes successfully. Besides, X-ray crystallography was used to verify the structure of NBDlyso, and the recognition mechanism involving photo-induced electron transfer was interpreted theoretically by means of DFT and TDDFT calculations skillfully when NBDlyso comes into play under the acidic condition. This probe showed good ability to sense pH change in living cell image. - Highlights: • An effective NBD-based fluorescent pH probe was developed. • The sensing mechanism was interpreted by theoretical calculation. • This probe was successfully used to monitor lysosoml pH changes in Hela cells.

  17. Nanoparticle-based luminescent probes for intracellular sensing and imaging of pH.

    Science.gov (United States)

    Schäferling, Michael

    2016-05-01

    Fluorescence imaging microscopy is an essential tool in biomedical research. Meanwhile, various fluorescent probes are available for the staining of cells, cell membranes, and organelles. Though, to monitor intracellular processes and dysfunctions, probes that respond to ubiquitous chemical parameters determining the cellular function such as pH, pO2 , and Ca(2+) are required. This review is focused on the progress in the design, fabrication, and application of photoluminescent nanoprobes for sensing and imaging of pH in living cells. The advantages of using nanoprobes carrying fluorescent pH indicators compared to single molecule probes are discussed as well as their limitations due to the mostly lysosomal uptake by cells. Particular attention is paid to ratiometric dual wavelength nanosensors that enable intrinsic referenced measurements. Referencing and proper calibration procedures are basic prerequisites to carry out reliable quantitative pH determinations in complex samples such as living cells. A variety of examples will be presented that highlight the diverseness of nanocarrier materials (polymers, micelles, silica, quantum dots, carbon dots, gold, photon upconversion nanocrystals, or bacteriophages), fluorescent pH indicators for the weak acidic range, and referenced sensing mechanisms, that have been applied intracellularly up to now. WIREs Nanomed Nanobiotechnol 2016, 8:378-413. doi: 10.1002/wnan.1366 For further resources related to this article, please visit the WIREs website. © 2015 Wiley Periodicals, Inc.

  18. Local pH Monitoring of Small Cluster of Cells using a Fiber-Optic Dual-Core Micro-Probe.

    Science.gov (United States)

    Chen, Sisi; Yang, Qingbo; Xiao, Hai; Shi, Honglan; Ma, Yinfa

    2017-03-31

    Biological studies of tissues and cells have enabled numerous discoveries, but these studies still bear potential risks of invalidation because of cell heterogeneity. Through high-accuracy techniques, recent studies have demonstrated that discrepancies do exist between the results from low-number-cell studies and cell-population-based results. Thus the urgent need to re-evaluate key principles on limited number of cells has been provoked. In this study, a novel designed dual-core fiber-optic pH micro-probe was fabricated and demonstrated for niche environment pH sensing with high spatial resolution. An organic-modified silicate (OrMoSils) sol-gel thin layer was functionalized by entrapping a pH indicator, 2', 7'-Bis (2-carbonylethyl)-5(6)-carboxyfluorescein (BCECF), on a ~70 μm sized probe tip. Good linear correlation between fluorescence ratio of I 560 nm /I 640 nm and intercellular pH values was obtained within a biological-relevant pH range from 6.20 to 7.92 (R 2 = 0.9834), and with a pH resolution of 0.035 ± 0.005 pH units. The probe's horizontal spatial resolution was demonstrated to be less than 2mm. Moreover, the probe was evaluated by measuring the localized extracellular pH changes of cultured human lung cancer cells (A549) when exposed to titanium dioxide nanoparticles (TiO 2 NPs). Results showed that the probe has superior capability for fast, local, and continual monitoring of a small cluster of cells, which provides researchers a fast and accurate technique to conduct local pH measurements for cell heterogeneity-related studies.

  19. Dansyl-8-aminoquinoline as a sensitive pH fluorescent probe with dual-responsive ranges in aqueous solutions.

    Science.gov (United States)

    Zhang, Min; Zheng, Shuyu; Ma, Liguo; Zhao, Meili; Deng, Lengfang; Yang, Liting; Ma, Li-Jun

    2014-04-24

    A sensitive pH fluorescent probe based on dansyl group, dansyl-8-aminoquinoline (DAQ), has been synthesized. The probe showed dual-responsive ranges to pH changes, one range from 2.00 to 7.95 and another one from 7.95 to 10.87 in aqueous solution, as it showed pKa values of 5.73 and 8.56 under acid and basic conditions, respectively. Furthermore, the pH response mechanism of the probe was explored successfully by using NMR spectra. The results indicated that the responses of DAQ to pH changes should attribute to the protonation of the nitrogen atom in the dimethylamino group and deprotonation of sulfonamide group. Copyright © 2014. Published by Elsevier B.V.

  20. Test design requirements: Thermal conductivity probe testing

    International Nuclear Information System (INIS)

    Heath, R.E.

    1985-01-01

    This document establishes the test design requirements for development of a thermal conductivity probe test. The thermal conductivity probe determines in situ thermal conductivity using a line source transient heat conduction analysis. This document presents the rationale for thermal conductivity measurement using a thermal conductivity probe. A general test description is included. Support requirements along with design constraints are detailed to allow simple design of the thermal conductivity probe and test. The schedule and delivery requirements of the responsible test designer are also included. 7 refs., 1 fig

  1. Two rhodamine lactam modulated lysosome-targetable fluorescence probes for sensitively and selectively monitoring subcellular organelle pH change

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hongmei [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Wang, Cuiling [Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, College of Life Science, Northwest University, Xi' an 710069 (China); She, Mengyao; Zhu, Yuelu; Zhang, Jidong; Yang, Zheng [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Liu, Ping, E-mail: liuping@nwu.edu.cn [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Wang, Yaoyu [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China); Li, Jianli, E-mail: lijianli@nwu.edu.cn [Ministry of Education Key Laboratory of Synthetic and Natural Functional Molecule Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069 (China)

    2015-11-05

    Be a powerful technique for convenient detection of pH change in living cells, especially at subcellular level, fluorescent probes has attracted more and more attention. In this work, we designed and synthesized three rhodamine lactam modulated fluorescent probes RS1, RS2 and RS3, which all respond sensitively toward weak acidity (pH range 4–6) via the photophysical property in buffer solution without interference from the other metal ions, and they also show ideal pKa values and excellent reversibility. Particularly, by changing the lone pair electrons distribution of lactam-N atom with different conjugations, RS2 and RS3 exhibit high quantum yield, negligible cytotoxicity and excellent permeability. They are suitable to stain selectively lysosomes of tumor cells and monitor its pH changes sensitively via optical molecular imaging. The above findings suggest that the probes we designed could act as ideal and easy method for investigating the pivotal role of H{sup +} in lysosomes and are potential pH detectors in disease diagnosis through direct intracellular imaging. - Highlights: • Two probes for sensitively and selectively monitoring weak acidic pH change. • The pKa of the probes was highly suitable for staining lysosomes in tumor cells. • The properties of those probes were changed by different conjugate system. • These probes have negligible cytotoxicity and good sensitivity in vivo.

  2. Two rhodamine lactam modulated lysosome-targetable fluorescence probes for sensitively and selectively monitoring subcellular organelle pH change

    International Nuclear Information System (INIS)

    Li, Hongmei; Wang, Cuiling; She, Mengyao; Zhu, Yuelu; Zhang, Jidong; Yang, Zheng; Liu, Ping; Wang, Yaoyu; Li, Jianli

    2015-01-01

    Be a powerful technique for convenient detection of pH change in living cells, especially at subcellular level, fluorescent probes has attracted more and more attention. In this work, we designed and synthesized three rhodamine lactam modulated fluorescent probes RS1, RS2 and RS3, which all respond sensitively toward weak acidity (pH range 4–6) via the photophysical property in buffer solution without interference from the other metal ions, and they also show ideal pKa values and excellent reversibility. Particularly, by changing the lone pair electrons distribution of lactam-N atom with different conjugations, RS2 and RS3 exhibit high quantum yield, negligible cytotoxicity and excellent permeability. They are suitable to stain selectively lysosomes of tumor cells and monitor its pH changes sensitively via optical molecular imaging. The above findings suggest that the probes we designed could act as ideal and easy method for investigating the pivotal role of H + in lysosomes and are potential pH detectors in disease diagnosis through direct intracellular imaging. - Highlights: • Two probes for sensitively and selectively monitoring weak acidic pH change. • The pKa of the probes was highly suitable for staining lysosomes in tumor cells. • The properties of those probes were changed by different conjugate system. • These probes have negligible cytotoxicity and good sensitivity in vivo.

  3. A NBD-based simple but effective fluorescent pH probe for imaging of lysosomes in living cells.

    Science.gov (United States)

    Cao, Xiang-Jian; Chen, Li-Na; Zhang, Xuan; Liu, Jin-Ting; Chen, Ming-Yu; Wu, Qiu-Rong; Miao, Jun-Ying; Zhao, Bao-Xiang

    2016-05-12

    NBDlyso with lysosome-locating morpholine moiety has been developed as a high selective and sensitive fluorescent pH probe. This probe can respond to acidic pH (2.0-7.0) in a short time (less than 1 min) and not almost change after continuously illuminated for an extended period by ultraviolet light. The fluorescence intensity of NBDlyso enhanced 100-fold in acidic solution, with very good linear relationship (R(2) = 0.996). The pKa of probe NBDlyso is 4.10. Therefore, NBDlyso was used to detect lysosomal pH changes successfully. Besides, X-ray crystallography was used to verify the structure of NBDlyso, and the recognition mechanism involving photo-induced electron transfer was interpreted theoretically by means of DFT and TDDFT calculations skillfully when NBDlyso comes into play under the acidic condition. This probe showed good ability to sense pH change in living cell image. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. A novel ''donor-π-acceptor'' type fluorescence probe for sensing pH: mechanism and application in vivo.

    Science.gov (United States)

    Chao, Jianbin; Wang, Huijuan; Zhang, Yongbin; Yin, Caixia; Huo, Fangjun; Song, Kailun; Li, Zhiqing; Zhang, Ting; Zhao, Yaqin

    2017-11-01

    A novel pH fluorescent probe 1-(pyren-1-yl)-3-(6-methoxypridin-3-yl)-acrylketone, (PMPA), which had a pyrene structure attached to methoxypyridine, was synthesized for monitoring extremely acidic and alkaline pH. The pH titrations indicated that PMPA displayed a remarkable emission enhancement with a pK a of 2.70 and responded linearly to minor pH fluctuations within the extremely acidic range of 1.26-3.97. Interestingly, PMPA also exhibited strong pH-dependent characteristics with pK a 9.32 and linear response to extreme-alkalinity range of 8.54-10.36. In addition, PMPA displayed a good selectivity, excellent photostability and large Stokes shift (167nm). Furthermore, the probe PMPA had excellent cell membrane permeability and was applied successfully to rapidly detect pH in living cells. pH value in these organs was closely related to many diseases, so these findings suggested that the probe had potential application in pH detecting for disease diagnosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. A fluorescent pH probe for acidic organelles in living cells.

    Science.gov (United States)

    Chen, Jyun-Wei; Chen, Chih-Ming; Chang, Cheng-Chung

    2017-09-26

    A water-soluble pH sensor, 2-(6-(4-aminostyryl)-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)-N, N-dimethylethanamine (ADA), was synthesized based on the molecular design of photoinduced electron transfer (PET) and intramolecular charge transfer (ICT). The fluorescence emission response against a pH value is in the range 3-6, which is suitable for labelling intracellular pH-dependent microenvironments. After biological evolution, ADA is more than a pH biosensor because it is also an endocytosis pathway tracking biosensor that labels endosomes, late endosomes, and lysosome pH gradients. From this, the emissive aggregates of ADA and protonated-ADA in these organs were evaluated to explore how this probe stresses emission colour change to cause these unique cellular images.

  6. Probe tests microweld strength

    Science.gov (United States)

    1965-01-01

    Probe is developed to test strength of soldered, brazed or microwelded joints. It consists of a spring which may be adjusted to the desired test pressure by means of a threaded probe head, and an indicator lamp. Device may be used for electronic equipment testing.

  7. Fetal scalp pH testing

    Science.gov (United States)

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

  8. Acid loading test (pH)

    Science.gov (United States)

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

  9. A novel optical probe for pH sensing in gastro-esophageal apparatus

    Science.gov (United States)

    Baldini, F.; Ghini, G.; Giannetti, A.; Senesi, F.; Trono, C.

    2011-03-01

    Monitoring gastric pH for long periods, usually 24 h, may be essential in analyzing the physiological pattern of acidity, in obtaining information on changes in activity during peptic ulcer disease, and in assessing the effect of antisecretory drugs. Gastro-esophageal reflux, which causes a pH decrease in the esophagus content from pH 7 even down to pH 2, can determine esophagitis with possible strictures and Barrett's esophagus. One of the difficulties of the optical measurement of pH in the gastro-esophageal apparatus lies in the required extended working range from 1 to 8 pH units. The present paper deals with a novel optical pH sensor, using methyl red as optical pH indicator. Contrary to all acidbase indicators characterized by working ranges limited to 2-3 pH units, methyl red, after its covalent immobilization on controlled pore glass (CPG), is characterized by a wide working range which fits with the clinical requirements. The novel probe design here described is suitable for gastro-esophageal applications and allows the optimization of the performances of the CPG with the immobilised indicator. This leads to a very simple configuration characterized by a very fast response time.

  10. Ratiometric pH Imaging with a CoII2 MRI Probe via CEST Effects of Opposing pH Dependences (Postprint)

    Science.gov (United States)

    2017-10-13

    acid-catalyzed proton exchange, respectively. Importantly, the pH calibration curve is independent of the probe concentration and is identical in...in aqueous solutions containing 50 mM HEPES and 100 mM NaCl buffered at various pH values were acquired using D2O in an inner capillary to lock the...ppm using a presaturation pulse applied for 6 s at a power level (B1) of 24 μT. D2O was placed in an inner capillary within the NMR sample tube to lock

  11. Novel lanthanide pH fluorescent probes based on multiple emissions and its visible-light-sensitized feature

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jintai [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Zheng, Yuhui, E-mail: yhzheng78@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Guangzhou Key Laboratory of Materials for Energy Conversion and Storage, Guangzhou 510006 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Zeng, Zhi [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Zhang, Cheng Cheng [Departments of Physiology and Developmental Biology, University of Texas Southwestern Medical Center, Dallas (United States)

    2014-08-11

    Graphical abstract: A new type of Eu(III) ofloxacin complex as the fluorescent pH indicator has been reported. Compared to pure ligand, the complex offers more distinguished color changes (green–red–blue) derived from both lanthanide line emissions and the secondary ionization steps of ofloxacin. - Highlights: • The pH probe offers a very wide working range in water (pH 1–14). • The emission changes have multiple colors. • Long-lived excited state lifetimes of Eu(III) has been used. • Two types of pH sensitive hydrogels were fabricated. - Abstract: A new type of Eu(III) ofloxacin complex as the fluorescent pH indicator has been presented. Compared to pure ligand, the complex offers more distinguished color changes (green–red–blue) derived from both lanthanide line emissions and the secondary ionization steps of ofloxacin. During the concentration dependence experiments, the photoluminescence studies on the complex showed that the excitation of this pH probe can occur at a very long wavelength which extends to visible range (Ex = 427 nm). Furthermore, the functional complex was successfully incorporated into soft networks and two novel luminescent hydrogels (rod and film) were fabricated. The soft materials also exhibited specific responses towards the pH variation. Finally, the onion cell-stain experiments were carried out to further confirm the validity of pH dependence and the results support the idea that the material will be suitable for monitoring biological samples in the future.

  12. Difference flow measurements and hydraulic interference test in ONKALO at Olkiluoto drillholes ONK-PH16 and ONK-PH17

    Energy Technology Data Exchange (ETDEWEB)

    Komulainen, J.; Pekkanen, J. [Poyry Finland Oy, Espoo (Finland)

    2012-08-15

    The Posiva Flow Log, Difference Flow Method (PFL DIFF) uses a flowmeter that incorporates a flow guide and can be used for relatively quick determinations of hydraulic conductivity and hydraulic head in fractures/fractured zones in cored drillholes. This report presents the principles of the method as well as the results of the measurements carried out in the underground facilities of ONKALO. The measurements were conducted in pilot holes ONK-PH16 and ONK-PH17 between October 12 and December 29, 2010. The aim of the measurements was to detect water conducting fractures and hydraulic interference between pilot holes ONK-PH16 and ONK-PH17. The flow rate into a 0.5 m long test section was measured using 0.1 m point intervals. The flowing fractures in both pilot holes were obtained between 50 m - 80 m. For hydraulic interference test one drillhole was closed with packers to increase its pressure. Flow response to the increased pressure was measured in the other drillhole. The flow guide of the PFL DIFF probe encloses an electrode for single point resistance measurement, which was carried out with 0.01 m point intervals during the automatic flow measurements. The flow measurement and the single point resistance measurement were used to locate flowing fractures and evaluate their transmissivity. Electrical conductivity (EC) and temperature of water were registered during automatic flow logging. The conductivity values are temperature corrected to 25 deg C. The distance between the drillholes is about 14 m. Flow response in fractures of open ONK-PH16 could be detected when pressure was changed in ONK-PH17. (orig.)

  13. A novel fluorescence probe based on triphenylamine Schiff base for bioimaging and responding to pH and Fe3+

    International Nuclear Information System (INIS)

    Wang, Lei; Yang, Xiaodong; Chen, Xiuli; Zhou, Yuping; Lu, Xiaodan; Yan, Chenggong; Xu, Yikai; Liu, Ruiyuan; Qu, Jinqing

    2017-01-01

    A novel fluorescence probe 1 based on triphenylamine was synthesized and characterized by NMR, IR, high resolution mass spectrometry and elemental analysis. Its fluorescence was quenched when pH below 2. There was a linear relationship between the fluorescence intensity and pH value ranged from 2 to 7. And its fluorescence emission was reversibility in acidic and alkaline solution. Furthermore, it exhibited remarkable selectivity and high sensitivity to Fe 3+ and was able to detect Fe 3+ in aqueous solution with low detection limit of 0.511 μM. Job plot showed that the binding stoichiometry of 1 with Fe 3+ was 1:1. Further observations of 1 H NMR titration suggested that coordination interaction between Fe 3+ and nitrogen atom on C =N bond promoted the intramolecular charge transfer (ICT) or energy transfer process causing fluorescence quenching. Additionally, 1 was also able to be applied for detecting Fe 3+ in living cell and bioimaging. - Graphical abstract: Triphenylamine based fluorescence probe can detect pH and Fe 3+ simultaneously in aqueous solution and be applied for detecting Fe 3+ in living cell and bioimaging. - Highlights: • The fluorescence probe is sensitive to pH in strong acid conditions. • The fluorescence chemosensor can detect pH and Fe 3+ simultaneously. • The recognition is able to carry out in aqueous solution. • The probe can also be applied for detecting Fe 3+ in living cell and bioimaging. • The sensor is synthesized easily with one step.

  14. New Photochrome Probe Allows Simultaneous pH and Microviscosity Sensing.

    Science.gov (United States)

    Wu, Yuanyuan; Papper, Vladislav; Pokholenko, Oleksandr; Kharlanov, Vladimir; Zhou, Yubin; Steele, Terry W J; Marks, Robert S

    2015-07-01

    4-N,N'-dimethylamino-4'-N'-stilbenemaleamic acid (DASMA), a unique molecular photochrome probe that exhibits solubility and retains trans-cis photoisomerisation in a wide range of organic solvents and aqueous pH environments, was prepared, purified and chemically characterised. Absorption, fluorescence excitation and emission spectra and constant-illumination fluorescence decay were measured in acetonitrile, dimethyl sulfoxide, ethanol, propylene carbonate, and aqueous glycerol mixtures. The pseudo-first-order fluorescence decay rates were found to be strongly dependent on the medium viscosity. In addition, the molecule exhibited the pH-dependent fluorescence and photoisomerisation kinetics.

  15. A ratiometric rhodamine–naphthalimide pH selective probe built on the basis of a PAMAM light-harvesting architecture

    International Nuclear Information System (INIS)

    Alamry, Khalid A.; Georgiev, Nikolai I.; El-Daly, Samy Abdullah; Taib, Layla A.; Bojinov, Vladimir B.

    2015-01-01

    PAMAM light harvesting antenna of second generation was synthesized and investigated. Novel compound was configured as a wavelength-shifting bichromophoric molecule where the system surface is labeled with yellow-green emitting 4-(N,N-dimethylamino)ethylamino-1,8-naphthalimide “donor” units capable of absorbing light and efficiently transferring the energy to a focal Rhodamine 6G “acceptor”. Furthermore, the 1,8-naphthalimide periphery of the system was designed on the “fluorophore-spacer-receptor” format, capable of acting as a molecular fluorescence photoinduced electron transfer based probe. Due to the both effects, photoinduced electron transfer in the periphery of the system and pH dependent rhodamine core absorption, novel antenna is able to act as a selective ratiometric pH fluorescence probe in aqueous medium. Thus, the distinguishing features of light-harvesting systems (fluorescence resonance energy transfer) were successfully combined with the properties of classical ring-opening sensor systems, which may be beneficial for monitoring pH variations in complex samples. - Highlights: • PAMAM antenna decorated with Rhodamine 6G and 1,8-naphthalimides is synthesized. • Periphery of the antenna is designed as a PET based fluorescence probe. • System manifests excellent selective response to protons in aqueous medium. • Core emission of the systems is enhanced more than 10 times as a function of pH. • Bichromophoric system acts as a selective ratiometric probe in complex samples

  16. Synthesis of a new benzanthrone probe for pH determination based on PET and ICT

    International Nuclear Information System (INIS)

    Miladinova, Polya M.

    2016-01-01

    The synthesis and sensor activity of a novel benzanthrone fluoropore is reported. The system is configured on the “fluoropore–receptor_1–spacer–receptor_2” model able to act as a pH-probe via PET and ICT fluorescence sensing mechanism. The novel probe shows “off-on-off” switching properties under the transition from alkaline to acid media. Keywords: benzanthrone derivative, photoinduced electron transfer (PET), Internal Charge Transfer (ICT), selective pH sensor.

  17. Single isotopic probe for gastro-esophageal reflux diagnosis in children

    Energy Technology Data Exchange (ETDEWEB)

    Maurel, G.; Le Moing, G.; Mensch, B.

    1987-03-01

    Gastro-esophageal reflux (GER) in children has been implicated in various recurring respiratory diseases. Several techniques including oesophageal pH testing and scintigraphy have been devised to detect and quantify GER Limitations have been found for each test: short duration with gamma-camera and restricted acceptability of the pH probe by children. A single isotopic probe was designed for a non-invasive screening test of GER in infants. This device was checked by comparison with oesophageal scintigraphy using a gamma camera. Only 1 discrepancy was detected in 19 reflux episodes. This method, using a relatively inexpensive detector and data acquisition module, seems to be well accepted by children, and may be associated with a pH probe for GER diagnosis.

  18. Reflection-mode micro-spherical fiber-optic probes for in vitro real-time and single-cell level pH sensing.

    Science.gov (United States)

    Yang, Qingbo; Wang, Hanzheng; Lan, Xinwei; Cheng, Baokai; Chen, Sisi; Shi, Honglan; Xiao, Hai; Ma, Yinfa

    2015-02-01

    pH sensing at the single-cell level without negatively affecting living cells is very important but still a remaining issue in the biomedical studies. A 70 μm reflection-mode fiber-optic micro-pH sensor was designed and fabricated by dip-coating thin layer of organically modified aerogel onto a tapered spherical probe head. A pH sensitive fluorescent dye 2', 7'-Bis (2-carbonylethyl)-5(6)-carboxyfluorescein (BCECF) was employed and covalently bonded within the aerogel networks. By tuning the alkoxide mixing ratio and adjusting hexamethyldisilazane (HMDS) priming procedure, the sensor can be optimized to have high stability and pH sensing ability. The in vitro real-time sensing capability was then demonstrated in a simple spectroscopic way, and showed linear measurement responses with a pH resolution up to an average of 0.049 pH unit within a narrow, but biological meaningful pH range of 6.12-7.81. Its novel characterizations of high spatial resolution, reflection mode operation, fast response and high stability, great linear response within biological meaningful pH range and high pH resolutions, make this novel pH probe a very cost-effective tool for chemical/biological sensing, especially within the single cell level research field.

  19. A novel fluorescence probe based on triphenylamine Schiff base for bioimaging and responding to pH and Fe{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lei; Yang, Xiaodong; Chen, Xiuli [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Zhou, Yuping [Guangdong Provincial key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515 (China); Lu, Xiaodan; Yan, Chenggong; Xu, Yikai [Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Liu, Ruiyuan, E-mail: ruiyliu@smu.edu.cn [Guangdong Provincial key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515 (China); Qu, Jinqing, E-mail: cejqqu@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China)

    2017-03-01

    A novel fluorescence probe 1 based on triphenylamine was synthesized and characterized by NMR, IR, high resolution mass spectrometry and elemental analysis. Its fluorescence was quenched when pH below 2. There was a linear relationship between the fluorescence intensity and pH value ranged from 2 to 7. And its fluorescence emission was reversibility in acidic and alkaline solution. Furthermore, it exhibited remarkable selectivity and high sensitivity to Fe{sup 3+} and was able to detect Fe{sup 3+} in aqueous solution with low detection limit of 0.511 μM. Job plot showed that the binding stoichiometry of 1 with Fe{sup 3+} was 1:1. Further observations of {sup 1}H NMR titration suggested that coordination interaction between Fe{sup 3+} and nitrogen atom on C =N bond promoted the intramolecular charge transfer (ICT) or energy transfer process causing fluorescence quenching. Additionally, 1 was also able to be applied for detecting Fe{sup 3+} in living cell and bioimaging. - Graphical abstract: Triphenylamine based fluorescence probe can detect pH and Fe{sup 3+} simultaneously in aqueous solution and be applied for detecting Fe{sup 3+} in living cell and bioimaging. - Highlights: • The fluorescence probe is sensitive to pH in strong acid conditions. • The fluorescence chemosensor can detect pH and Fe{sup 3+} simultaneously. • The recognition is able to carry out in aqueous solution. • The probe can also be applied for detecting Fe{sup 3+} in living cell and bioimaging. • The sensor is synthesized easily with one step.

  20. Single isotopic probe for gastro-esophageal reflux diagnosis in children

    International Nuclear Information System (INIS)

    Maurel, G.; Le Moing, G.; Mensch, B.

    1987-01-01

    Gastro-esophageal reflux (G.E.R.) in children has been implicated in various recurring respiratory diseases. Several techniques including oesophageal pH testing and scintigraphy have been devised to detect and quantify G.E.R. Limitations have been found for each test: short duration with gamma-camera and restricted acceptability of the pH probe by children. A single isotopic probe was designed for a non-invasive screening test of G.E.R. in infants. This device was checked by comparison with oesophageal scintigraphy using a gamma camera. Only 1 discrepancy was detected in 19 reflux episodes. This method, using a relatively inexpensive detector and data acquisition module, seems to be well accepted by children, and may be associated with a pH probe for GER diagnosis. (orig.)

  1. Cone penetrometer moisture probe acceptance test report

    International Nuclear Information System (INIS)

    Barnes, G.A.

    1996-01-01

    This Acceptance Test Report (ATR) documents the results of WHC-SD-WM-ATP-146 (Prototype Cone Penetrometer Moisture Probe Acceptance Test Procedure) and WHC-SD-WM-ATP-145 (Cone Penetrometer Moisture Probe Acceptance Test Procedure). The master copy of WHC-SD-WM-ATP-145 can be found in Appendix A and the master copy of WHC-SD-WM-ATP-146 can be found in Appendix B. Also included with this report is a matrix showing design criteria of the cone penetrometer moisture probe and the verification method used (Appendix C)

  2. Urine pH test

    Science.gov (United States)

    ... urine test Male urinary tract References Bose A, Monk RD, Bushinsky DA. Kidney stones. In: Melmed S, Polonsky ... and its influence on urine pH. J Am Diet Assoc . 1995;95(7):791-797. PMID: 7797810 ...

  3. Synthesis and sensor activity of a PET-based 1,8-naphthalimide Probe for Zn(2+) and pH determination.

    Science.gov (United States)

    Dimov, Stefan M; Georgiev, Nikolai I; Asiri, Abdullah M; Bojinov, Vladimir B

    2014-11-01

    A novel blue-emitting 1,8-naphthalimide fluorophore designed as a molecular PET-based probe for determination of pH and detection of transition metal ions in the environment was successfully synthesized. Novel compound was configured on the "fluorophore-spacer-receptor" format. Due to the tertiary amine receptor the novel system showed "off-on" switching properties under the transition from alkaline to acid media (FE = 3.2) and in the presence of Zn(2+) ions (FE = 2.5). The results obtained illustrate the high potential of the synthesized blue-emitting 1,8-naphthalimide fluorophore as an efficient pH chemosensing material and a selective probe for Zn(2+) ions.

  4. Biological pH sensing based on the environmentally friendly Raman technique through a polyaniline probe.

    Science.gov (United States)

    Li, Songyang; Liu, Zhiming; Su, Chengkang; Chen, Haolin; Fei, Xixi; Guo, Zhouyi

    2017-02-01

    The biological pH plays an important role in various cellular processes. In this work, a novel strategy is reported for biological pH sensing by using Raman spectroscopy and polyaniline nanoparticles (PANI NPs) as the pH-sensitive Raman probe. It is found that the Raman spectrum of PANI NPs is strongly dependent on the pH value. The intensities of Raman spectral bands at 1225 and 1454 cm -1 increase obviously with pH value varying from 5.5 to 8.0, which covers the range of regular biological pH variation. The pH-dependent Raman performance of PANI NPs, as well as their robust Raman signals and sensitivities to pH, was well retained after the nanoparticles incorporated into living 4T1 breast adenocarcinoma cells. The data indicate that such PANI NPs can be used as an effective biological pH sensor. Most interestingly, the PANI spherical nanostructures can be acquired by a low-cost, metal-free, and one-pot oxidative polymerization, which gives them excellent biocompatibility for further biological applications.

  5. Synthesis and spectral properties of novel chlorinated pH fluorescent probes

    International Nuclear Information System (INIS)

    Wu Xianglong; Jin Xilang; Wang Yunxia; Mei Qibing; Li Jianli; Shi Zhen

    2011-01-01

    Eight chlorinated fluoresceins have been synthesized by the reaction of chlorinated resorcinols with 4, 5, 6, 7-tetrachlorophthalic anhydride or 3, 6-dichloro-4-carboxyphthalic anhydride in the presence of methanesulfonic acid. The spectral properties of the chlorinated fluoresceins were studied. It was found that they have absorption and emission maxima at long wavelengths and high fluorescence quantum yields. Emission spectra of chlorinated fluoresceins shifted towards long wavelength with increase in chlorine. pH-dependent properties of chlorinated fluoresceins were studied in detail. These compounds showed a strongly pH-sensitive range of 3.0-7.0. These chlorinated fluoresceins will be used as pH probes for pH measurement of the cell because of the high quantum yield and strong pH-sensitivity. - Research highlights: → Eight chlorinated fluoresceins have been synthesized in the presence of methanesulfonic acid. → Emission spectra of these compounds shifted towards long wavelength with increase in chlorine. → Eight chlorinated fluoresceins showed a strongly pH-sensitive range of 3.0-7.0. → They have emission maxima at long wavelengths and high fluorescence quantum yields.

  6. New Amino-Acid-Based β-Phosphorylated Nitroxides for Probing Acidic pH in Biological Systems by EPR Spectroscopy.

    Science.gov (United States)

    Thétiot-Laurent, Sophie; Gosset, Gaëlle; Clément, Jean-Louis; Cassien, Mathieu; Mercier, Anne; Siri, Didier; Gaudel-Siri, Anouk; Rockenbauer, Antal; Culcasi, Marcel; Pietri, Sylvia

    2017-02-01

    There is increasing interest in measuring pH in biological samples by using nitroxides with pH-dependent electron paramagnetic resonance (EPR) spectra. Aiming to improve the spectral sensitivity (Δa X ) of these probes (i.e., the difference between the EPR hyperfine splitting (hfs) in their protonated and unprotonated forms), we characterized a series of novel linear α-carboxy, α'-diethoxyphosphoryl nitroxides constructed on an amino acid core and featuring an (α or α')-C-H bond. In buffer, the three main hfs (a N , a H , and a P ) of their EPR spectra vary reversibly with pH and, from a P or a H titration curves, a two- to fourfold increase in sensitivity was achieved compared to reference imidazoline or imidazolidine nitroxides. The crystallized carboxylate 10 b (pK a ≈3.6), which demonstrated low cytotoxicity and good resistance to bioreduction, was applied to probe stomach acidity in rats. The results pave the way to a novel generation of highly sensitive EPR pH markers. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Test module development to detect the flase call probe pins on microeprocessor test equipment

    Science.gov (United States)

    Tang, L. W.; Ong, N. R.; Mohamad, I. S. B.; Alcain, J. B.; Retnasamy, V.

    2017-09-01

    Probe pins are useful for electrical testing of microelectronic components, printed circuit board assembly (PCBA), microprocessors and other electronic devices due to it provides the conductivity test based on specific device circuit design. During the repeatable test runs, the load of test modules, contact failures and the current conductivity induces layer wear off all the tip of probe pins contact. Contamination will be build-up on probe pins and increased contact resistivity which results of cost loss and time loss for rectifying programs, rectifying testers and exchanging new probe pins. In this study, a resistivity approach will be developed to provide "Testing of Test Probes". The test module based on "Four-wire Ohm measurement" method with two alternative ways of applying power supply, that are 9V from a single power supply and 5V from Arduino UNO power supply were demonstrated to measure the small resistance value of microprocessor probe pin. A microcontroller with VEE Pro software was used to record the measurement data. The accuracy of both test modules were calibrated under different temperature conditions and result shows that 9V from a single power supply test module has higher measurement accuracy.

  8. Multi-point probe for testing electrical properties and a method of producing a multi-point probe

    DEFF Research Database (Denmark)

    2011-01-01

    A multi-point probe for testing electrical properties of a number of specific locations of a test sample comprises a supporting body defining a first surface, a first multitude of conductive probe arms (101-101'''), each of the probe arms defining a proximal end and a distal end. The probe arms...... of contact with the supporting body, and a maximum thickness perpendicular to its perpendicular bisector and its line of contact with the supporting body. Each of the probe arms has a specific area or point of contact (111-111''') at its distal end for contacting a specific location among the number...... of specific locations of the test sample. At least one of the probe arms has an extension defining a pointing distal end providing its specific area or point of contact located offset relative to its perpendicular bisector....

  9. A Reliable and Non-destructive Method for Monitoring the Stromal pH in Isolated Chloroplasts Using a Fluorescent pH Probe

    Directory of Open Access Journals (Sweden)

    Pai-Hsiang Su

    2017-12-01

    Full Text Available The proton gradient established by the pH difference across a biological membrane is essential for many physiological processes, including ATP synthesis and ion and metabolite transport. Currently, ionophores are used to study proton gradients, and determine their importance to biological functions of interest. Because of the lack of an easy method for monitoring the proton gradient across the inner envelope membrane of chloroplasts (ΔpHenv, whether the concentration of ionophores used can effectively abolish the ΔpHenv is not proven for most experiments. To overcome this hindrance, we tried to setup an easy method for real-time monitoring of the stromal pH in buffered, isolated chloroplasts by using fluorescent pH probes; using this method the ΔpHenv can be calculated by subtracting the buffer pH from the measured stromal pH. When three fluorescent dyes, BCECF-AM [2′,7′-bis-(2-carboxyethyl-5-(and-6-carboxyfluorescein acetoxymethyl ester], CFDA-SE [5(6-Carboxyfluorescein diacetate succinimidyl ester] and SNARF-1 carboxylic acid acetate succinimidyl ester were incubated with isolated chloroplasts, BCECF-AM and CFDA-SE, but not the ester-formed SNARF-1 were taken up by chloroplasts and digested with esterase to release high levels of fluorescence. According to its relatively higher pKa value (6.98, near the physiological pH of the stroma, BCECF was chosen for further development. Due to shielding of the excitation and emission lights by chloroplast pigments, the ratiometric fluorescence of BCECF was highly dependent on the concentration of chloroplasts. By using a fixed concentration of chloroplasts, a highly correlated standard curve of pH to the BCECF ratiometric fluorescence with an r-square value of 0.98 was obtained, indicating the reliability of this method. Consistent with previous reports, the light-dependent formation of ΔpHenv can be detected ranging from 0.15 to 0.33 pH units upon illumination. The concentration of the ionophore

  10. Nanosensors for pH measurements in plants

    DEFF Research Database (Denmark)

    Ytting, Cecilie Karkov; Fuglsang, Anja Thoe

    Traditionally in vivo pH measurements in plants are carried out using different fluorescent probes such as BCECF and SNARFs by injecting plant cells or incubating tissues with the probes. This approach, however, carries several problems, the most important one being the handling of the plant cells...... or tissues. Stress and wounding of the plant can possibly influence the outcome of the pH measurements. Other problems are the difficulties of getting the probes more than a few cell layers into the plant tissue and to get an even distribution of the probe. Increasing numbers of different variants...... of the green fluorescent protein, GFP, have become available, some of which are pH sensitive. This offers the opportunity to simply express the pH sensitive protein in different plant tissues, making it possible to conduct in vivo pH measurements in a non-invasive manner. One sensor being characterized...

  11. Failure analysis on false call probe pins of microprocessor test equipment

    Science.gov (United States)

    Tang, L. W.; Ong, N. R.; Mohamad, I. S. B.; Alcain, J. B.; Retnasamy, V.

    2017-09-01

    A study has been conducted to investigate failure analysis on probe pins of test modules for microprocessor. The `health condition' of the probe pin is determined by the resistance value. A test module of 5V power supplied from Arduino UNO with "Four-wire Ohm measurement" method is implemented in this study to measure the resistance of the probe pins of a microprocessor. The probe pins from a scrapped computer motherboard is used as the test sample in this study. The functionality of the test module was validated with the pre-measurement experiment via VEE Pro software. Lastly, the experimental work have demonstrated that the implemented test module have the capability to identify the probe pin's `health condition' based on the measured resistance value.

  12. A probe station for testing silicon sensors

    CERN Multimedia

    Ulysse, Fichet

    2017-01-01

    A probe station for testing silicon sensors. The probe station is located inside a dark box that can keep away light during the measurement. The set-up is located in the DSF (Department Silicon Facility). The golden plate is the "chuck" where the sensor is usually placed on. With the help of "manipulators", thin needles can be precisely positioned that can contact the sensor surface. Using these needles and the golden chuck, a high voltage can be applied to the sensor to test its behaviour under high voltage. We will use the silicon sensors that we test here for building prototypes of a highly granular sandwich calorimeter, the CMS HGC (Highly granular Calorimeter) upgrade for High-Luminosity LHC.

  13. Slow aggregation of lysozyme in alkaline pH monitored in real time employing the fluorescence anisotropy of covalently labelled dansyl probe.

    Science.gov (United States)

    Homchaudhuri, Lopamudra; Kumar, Satish; Swaminathan, Rajaram

    2006-04-03

    The onset of hen egg white lysozyme aggregation on exposure to alkaline pH of 12.2 and subsequent slow growth of soluble lysozyme aggregates (at 298 K) was directly monitored by steady-state and time-resolved fluorescence anisotropy of covalently attached dansyl probe over a period of 24 h. The rotational correlation time accounting for tumbling of lysozyme in solution (40 microM) increased from approximately 3.6 ns (in pH 7) to approximately 40ns on exposure to pH 12.2 over a period of 6 h and remained stable thereafter. The growth of aggregates was strongly concentration dependent, irreversible after 60 min and inhibited by the presence of 0.9 M l-arginine in the medium. The day old aggregates were resistant to denaturation by 6 M guanidine.HCl. Our results reveal slow segmental motion of the dansyl probe in day old aggregates in the absence of L-arginine (0.9 M), but a much faster motion in its presence, when growth of aggregates is halted.

  14. Optical pH Sensor Covering the Range from pH 0-14 Compatible with Mobile-Device Readout and Based on a Set of Rationally Designed Indicator Dyes.

    Science.gov (United States)

    Gotor, Raúl; Ashokkumar, Pichandi; Hecht, Mandy; Keil, Karin; Rurack, Knut

    2017-08-15

    In this work, a family of pH-responsive fluorescent probes has been designed in a rational manner with the aid of quantum chemistry tools, covering the entire pH range from 0-14. Relying on the boron-dipyrromethene (BODIPY) core, all the probes as well as selected reference dyes display very similar spectroscopic properties with ON-OFF fluorescence switching responses, facilitating optical readout in simple devices used for detection and analysis. Embedding of the probes and reference dyes into hydrogel spots on a plastic strip yielded a test strip that reversibly indicates pH with a considerably small uncertainty of ∼0.1 pH units. These strips are not only reusable but, combined with a 3D-printed case that can be attached to a smartphone, the USB port of which drives the integrated LED used for excitation, allows for autonomous operation in on-site or in-the-field applications; the developed Android application software ("app") further simplifies operation for unskilled users.

  15. Context-dependent effects of hippocampal damage on memory in the shock-probe test.

    Science.gov (United States)

    Lehmann, Hugo; Carfagnini, Adrienne; Yamin, Stephanie; Mumby, Dave G

    2005-01-01

    We assessed the role of the hippocampus in anterograde memory, using the shock-probe test. Rats with sham or neurotoxic lesions of the hippocampus were given a shock-probe acquisition session during which each time they contacted a probe they received a shock; 24 h later, the rats were given a second shock-probe session to test their retention, but in this instance the probe was not electrified. Rats were tested in either the same context as the one used during acquisition or in a different context. The hippocampal lesions impaired avoidance of the probe and burying on the retention test, suggesting that the lesions induced anterograde amnesia. However, the impairment was context dependent. The hippocampal lesions impaired avoidance only when the rats were tested in the context in which they received the conditioning. The results of the shock-probe test suggest that the anterograde amnesia following hippocampal lesions is due mainly to an inability to associate the context with the shock more than to an inability to associate the probe with shock. Copyright (c) 2004 Wiley-Liss, Inc.

  16. Probe station for testing of ALICE silicon drift detectors

    CERN Document Server

    Humanic, T J; Piemonte, C; Rashevsky, A; Sugarbaker, E R; Vacchi, A

    2003-01-01

    Large area, 7.25 cm multiplied by 8.76 cm silicon drift detectors have been developed and are in production for the ALICE experiment at LHC. An active area of the detector of more than 50 cm**2 imposes high demands on the quality of processing and raw material. Automated testing procedures have been developed to test detectors before mounting them on the ladders. Probe stations for ALICE SDD testing were designed and built at INFN, Trieste and Ohio State University (OSU). Testing procedures, detector selection criteria and some details of the OSU probe station design are discussed.

  17. pH monitoring in patients with benign voice disorders

    DEFF Research Database (Denmark)

    Grøntved, A M; West, F

    2000-01-01

    The aim of this study was to compare oesophageal pH-metry with laryngeal signs and symptoms in patients suspected of laryngeal reflux disease. A total of 60 patients with voice disorders, who were suspected of laryngeal reflux, were tested by single probe oesophageal pH monitoring. Thirty...

  18. Nanosensors for pH measurements in plants

    OpenAIRE

    Ytting, Cecilie Karkov; Fuglsang, Anja Thoe

    2007-01-01

    Traditionally in vivo pH measurements in plants are carried out using different fluorescent probes such as BCECF and SNARFs by injecting plant cells or incubating tissues with the probes. This approach, however, carries several problems, the most important one being the handling of the plant cells or tissues. Stress and wounding of the plant can possibly influence the outcome of the pH measurements. Other problems are the difficulties of getting the probes more than a few cell layers into the...

  19. Peptide-targeted delivery of a pH sensor for quantitative measurements of intraglycosomal pH in live Trypanosoma brucei.

    Science.gov (United States)

    Lin, Sheng; Morris, Meredith T; Ackroyd, P Christine; Morris, James C; Christensen, Kenneth A

    2013-05-28

    Studies of dynamic changes in organelles of protozoan parasite Trypanosoma brucei have been limited, in part because of the difficulty of targeting analytical probes to specific subcellular compartments. Here we demonstrate application of a ratiometric probe for pH quantification in T. brucei glycosomes. The probe consists of a peptide encoding the peroxisomal targeting sequence (F-PTS1, acetyl-CKGGAKL) coupled to fluorescein, which responds to pH. When incubated with living parasites, the probe is internalized within vesicular structures that colocalize with a glycosomal marker. Inhibition of uptake of F-PTS1 at 4 °C and pulse-chase colocalization with fluorescent dextran suggested that the probe is initially taken up by non-receptor-mediated endocytosis but is subsequently transported separately from dextran and localized within glycosomes, prior to the final fusion of labeled glycosomes and lysosomes as part of glycosomal turnover. Intraorganellar measurements and pH calibration with F-PTS1 in T. brucei glycosomes indicate that the resting glycosomal pH under physiological conditions is 7.4 ± 0.2. However, incubation in glucose-depleted buffer triggered mild acidification of the glycosome over a period of 20 min, with a final observed pH of 6.8 ± 0.3. This glycosomal acidification was reversed by reintroduction of glucose. Coupling of ratiometric fluorescent sensors and reporters to PTS peptides offers an invaluable tool for monitoring in situ glycosomal response(s) to changing environmental conditions and could be applied to additional kinetoplastid parasites.

  20. Development of oxygen and pH sensors for aqueous systems

    International Nuclear Information System (INIS)

    Stvartak, C.; Alcock, C.B.; Li, B.; Wang, L.; Fergus, J.W.; Bakshi, N.

    1994-04-01

    Corrosion science has long recognized that two of the most important parameters in characterizing the corrosivity of an aqueous environment are oxygen chemical potential and pH. These parameters not only determine the thermodynamic driving forces for various corrosion reactions, but also characterize the rates of these reactions and hence the lifetime of a particular component. The primary goal of this project is to develop an electrochemical oxygen and pH sensor for continuous use in the cycle chemistry control of power plants. In the past year, electrochemical sensors with a metal/metal oxide or metal/metal hydride internal reference electrode and a fluoride-based electrolyte tube have been developed and tested in this laboratory. The corrosion tests showed that the LaF 3 -based solid electrolyte was very stable both chemically and physically in water. Furthermore, its electrical conductivity is 4 to 5 orders of magnitude higher than that of stabilized zirconia below 573 K (300 degree C), which is the main advantage of a fluoride-based electrolyte at low temperatures. With this electrolyte and the selected internal oxygen reference electrode (Ag/Ag 2 O), the electrochemical probe demonstrated Nernstian responses to the oxygen chemical potential and pH of the aqueous solution with good reproducibility. A similar cell with Zr/ZrH 1+x as the internal hydrogen reference electrode showed promising pH sensing characteristics. It is proposed that these two cells be combined to form a double-headed electrochemical probe to determine oxygen chemical potential and pH in the solution simultaneously

  1. Sub-micron opto-chemical probes for studying living neurons

    Science.gov (United States)

    Hossein-Zadeh, M.; Delgado, J.; Schweizer, F.; Lieberman, R.

    2017-02-01

    We have fabricated sub-micron opto-chemical probes for pH, oxygen and calcium monitoring and demonstrated their application in intracellular and extracellular monitoring of neurons (cortical neuronal cultures and acute hippocampal slices). Using these probes, we have measured extracellular pH in the stratum radiatum of the CA1 region of mouse hippocampus upon stimulation of presynaptic Schaffer collateral axons. Synaptic transmission was monitored using standard electrophysiological techniques. We find that the local pH transiently changes in response to synaptic stimulation. In addition, the geometry of the functionalized region on the probe combined with high sensitivity imaging enables simultaneous monitoring of spatially adjacent but distinct compartments. As proof of concept we impaled cultured neurons with the probe measured calcium and pH inside as well as directly outside of neurons as we changed the pH and calcium concentration in the physiological solution in the perfusion chamber. As such these probes can be used to study the impact of the environment on both cellular and extra-cellular space. Additionally as the chemical properties of the surrounding medium can be controlled and monitored with high precision, these probes enable differential measurement of the target parameter referenced to a stable bath. This approach eliminates the uncertainties associated with non-chemical fluctuations in the fluorescent emission and result in a self-calibrated opto-chemical probe. We have also demonstrated multifunctional probes that are capable of measuring up to three parameters in the extracellular space in brain slices.

  2. Selective imaging of cancer cells with a pH-activatable lysosome-targeting fluorescent probe.

    Science.gov (United States)

    Shi, Rongguang; Huang, Lu; Duan, Xiaoxue; Sun, Guohao; Yin, Gui; Wang, Ruiyong; Zhu, Jun-Jie

    2017-10-02

    Fluorescence imaging with tumor-specific fluorescent probe has emerged as a tool to aid surgeons in the identification and removal of tumor tissue. We report here a new lysosome-targeting fluorescent probe (NBOH) with BODIPY fluorephore to distinguish tumor tissue out of normal tissue based on different pH environment. The probe exhibited remarkable pH-dependent fluorescence behavior in a wide pH range from 3.0 to 11.0, especially a sensitive pH-dependent fluorescence change at pH range between 3.5 and 5.5, corresponding well to the acidic microenvironment of tumor cells, in aqueous solution. The response time of NBOH was extremely short and the photostability was proved to be good. Toxicity test and fluorescence cell imaging together with a sub-cellular localization study were carried out revealing its low biotoxicity and good cell membrane permeability. And NBOH was successfully applied to the imaging of tumor tissue in tumor-bearing mice suggesting potential application to surgery as a tumor-specific probe. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Is pH Testing Necessary Before Antireflux Surgery in Patients with Endoscopic Erosive Esophagitis?

    Science.gov (United States)

    Schwameis, Katrin; Lin, Brenda; Roman, Jordan; Olengue, Ketetha; Siegal, Steve; DeMeester, Steven R

    2018-01-01

    The relationship between the Los Angeles (LA) grade of esophagitis and acid exposure by pH monitoring is unclear. The aim of this study was to correlate the results of pH testing in patients with esophagitis to determine at what LA grade of esophagitis a pH test is not necessary. A retrospective review was performed of the records of all patients who underwent upper endoscopy and were found to have esophagitis graded using the LA system and who had pH monitoring from 2014 to 2016. An abnormal pH test was determined based on the DeMeester score. There were 56 patients with a median age of 57 years. Esophagitis was LA grade A in 19, B in 20, C in 15 and D in 2 patients. An abnormal pH score was present in 47 patients (84%). All patients with C or D esophagitis had an abnormal pH score compared to 79% and 75% of patients with A and B esophagitis, respectively. The presence of LA C or D esophagitis was always associated with increased esophageal acid exposure on pH testing and is proof of reflux disease. However, pH testing is recommended prior to antireflux surgery in patients with LA A or B esophagitis.

  4. Tests of Hadronic Probes of GT Strength

    CERN Multimedia

    2002-01-01

    There are many important problems where one wishes to know the distribution of Gamow-Teller (GT) strength in circumstances where it cannot be measured directly (for example, because of energy-release limitations). Then one must rely on hadronic probes to infer the GT strength. It is therefore essential to test these probes as extensively as possible. The isospin-analog transitions in $^{37}$Ca $\\beta^{+}$ -decay and $^{37}$Cl$(p, n)$ provide an excellent ground for such a test. Recent $^{37}$Cl$ (p, n) $ studies, while qualitatively in agreement with our previous ISOLDE work on $^{37}$Ca $\\beta^{+} $ -decay, show quantitative discrepancies that appear to grow as the excitation energy in the residual nuclei increases. Because of the bulk of the GT strengh appears at these high excitation energies, it is important to extend the $\\beta$-decay data to even higher excitation energies where, because of rapidly diminishing phase-space, strong GT transitions correspond to very weak $\\beta$ -branches. We propose to do...

  5. MIMO OTA Testing in Small Multi-Probe Anechoic Chamber Setups

    DEFF Research Database (Denmark)

    Llorente, Ines Carton; Fan, Wei; Pedersen, Gert F.

    2016-01-01

    OTA testing of MIMO capable terminals is often performed in large anechoic chambers, where planar waves impinging the test area are assumed. Furthermore, reflections from the chamber, and probe coupling are often considered negligible due to the large dimensions of the chamber. This paper...... investigates the feasibility of reducing the physical dimension of 2D multi-probe anechoic chamber setups for MIMO OTA testing, with the purpose of reducing the cost and space of the setup. In the paper, a channel emulation algorithm and chamber compensation technique are proposed for MIMO OTA testing in small...... anechoic chambers. The performance deterioration in a small anechoic chamber, i.e., with a ring radius of 0.5 m, is demonstrated via simulations....

  6. NASA SMART Probe: Breast Cancer Application

    Science.gov (United States)

    Mah, Robert W.; Norvig, Peter (Technical Monitor)

    2000-01-01

    There is evidence in breast cancer and other malignancies that the physiologic environment within a tumor correlates with clinical outcome. We are developing a unique percutaneous Smart Probe to be used at the time of needle biopsy of the breast. The Smart Probe will simultaneously measure multiple physiologic parameters within a breast tumor. Direct and indirect measurements of tissue oxygen levels, blood flow, pH, and tissue fluid pressure will be analyzed in real-time. These parameters will be interpreted individually and collectively by innovative neural network techniques using advanced intelligent software. The goals are 1) develop a pecutaneous Smart Probe with multiple sensor modalities and applying advanced Information Technologies to provide real time diagnostic information of the tissue at tip of the probe, 2) test the percutaneous Smart Probe in women with benign and malignant breast masses who will be undergoing surgical biopsy, 3) correlate probe sensor data with benign and malignant status of breast masses, 4) determine whether the probe can detect physiologic differences within a breast tumor, and its margins, and in adjacent normal breast tissue, 5) correlate probe sensor data with known prognostic factors for breast caner, including tumor size, tumor grade, axillary lymph node metastases, estrogen receptor and progesterone receptor status.

  7. Using membrane composition to fine-tune the pKa of an optical liposome pH sensor.

    Science.gov (United States)

    Clear, Kasey J; Virga, Katelyn; Gray, Lawrence; Smith, Bradley D

    2016-04-14

    Liposomes containing membrane-anchored pH-sensitive optical probes are valuable sensors for monitoring pH in various biomedical samples. The dynamic range of the sensor is maximized when the probe p K a is close to the expected sample pH. While some biomedical samples are close to neutral pH there are several circumstances where the pH is 1 or 2 units lower. Thus, there is a need to fine-tune the probe p K a in a predictable way. This investigation examined two lipid-conjugated optical probes, each with appended deep-red cyanine dyes containing indoline nitrogen atoms that are protonated in acid. The presence of anionic phospholipids in the liposomes stabilized the protonated probes and increased the probe p K a values by sensor for optimal pH sensing performance.

  8. A novel dansyl-based fluorescent probe for highly selective detection of ferric ions.

    Science.gov (United States)

    Yang, Min; Sun, Mingtai; Zhang, Zhongping; Wang, Suhua

    2013-02-15

    A novel dansyl-based fluorescent probe was synthesized and characterized. It exhibits high selectivity and sensitivity towards Fe(3+) ion. This fluorescent probe is photostable, water soluble and pH insensitive. The limit of detection is found to be 0.62 μM. These properties make it a good fluorescent probe for Fe(3+) ion detection in both chemical and biological systems. Spike recovery test confirms its practical application in tap water samples. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Label-Free Carbon-Dots-Based Ratiometric Fluorescence pH Nanoprobes for Intracellular pH Sensing.

    Science.gov (United States)

    Shangguan, Jingfang; He, Dinggeng; He, Xiaoxiao; Wang, Kemin; Xu, Fengzhou; Liu, Jinquan; Tang, Jinlu; Yang, Xue; Huang, Jin

    2016-08-02

    Measuring pH in living cells is of great importance for better understanding cellular functions as well as providing pivotal assistance for early diagnosis of diseases. In this work, we report the first use of a novel kind of label-free carbon dots for intracellular ratiometric fluorescence pH sensing. By simple one-pot hydrothermal treatment of citric acid and basic fuchsin, the carbon dots showing dual emission bands at 475 and 545 nm under single-wavelength excitation were synthesized. It is demonstrated that the fluorescence intensities of the as-synthesized carbon dots at the two emissions are pH-sensitive simultaneously. The intensity ratio (I475 nm/I545 nm) is linear against pH values from 5.2 to 8.8 in buffer solution, affording the capability as ratiometric probes for intracellular pH sensing. It also displays that the carbon dots show excellent reversibility and photostability in pH measurements. With this nanoprobe, quantitative fluorescence imaging using the ratio of two emissions (I475 nm/I545 nm) for the detection of intracellular pH were successfully applied in HeLa cells. In contrast to most of the reported nanomaterials-based ratiometric pH sensors which rely on the attachment of additional dyes, these carbon-dots-based ratiometric probes are low in toxicity, easy to synthesize, and free from labels.

  10. Specificity tests of an oligonucleotide probe against food-outbreak salmonella for biosensor detection

    Science.gov (United States)

    Chen, I.-H.; Horikawa, S.; Xi, J.; Wikle, H. C.; Barbaree, J. M.; Chin, B. A.

    2017-05-01

    Phage based magneto-elastic (ME) biosensors have been shown to be able to rapidly detect Salmonella in various food systems to serve food pathogen monitoring purposes. In this ME biosensor platform, the free-standing strip-shaped magneto-elastic sensor is the transducer and the phage probe that recognizes Salmonella in food serves as the bio-recognition element. According to Sorokulova et al. at 2005, a developed oligonucleotide probe E2 was reported to have high specificity to Salmonella enterica Typhimurium. In the report, the specificity tests were focused in most of Enterobacterace groups outside of Salmonella family. Here, to understand the specificity of phage E2 to different Salmonella enterica serotypes within Salmonella Family, we further tested the specificity of the phage probe to thirty-two Salmonella serotypes that were present in the major foodborne outbreaks during the past ten years (according to Centers for Disease Control and Prevention). The tests were conducted through an Enzyme linked Immunosorbent Assay (ELISA) format. This assay can mimic probe immobilized conditions on the magnetoelastic biosensor platform and also enable to study the binding specificity of oligonucleotide probes toward different Salmonella while avoiding phage/ sensor lot variations. Test results confirmed that this oligonucleotide probe E2 was high specific to Salmonella Typhimurium cells but showed cross reactivity to Salmonella Tennessee and four other serotypes among the thirty-two tested Salmonella serotypes.

  11. 2D ratiometric fluorescent pH sensor for tracking of cells proliferation and metabolism.

    Science.gov (United States)

    Ma, Jun; Ding, Changqin; Zhou, Jie; Tian, Yang

    2015-08-15

    Extracellular pH plays a vital role no matter in physiological or pathological studies. In this work, a hydrogel, CD@Nile-FITC@Gel (Gel sensor), entrapping the ratiometric fluorescent probe CD@Nile-FITC was developed. The Gel sensor was successfully used for real-time extracellular pH monitoring. In the case of CD@Nile-FITC, pH-sensitive fluorescent dye fluorescein isothiocyanate (FITC) was chosen as the response signal for H(+) and Nile blue chloride (Nile) as the reference signal. The developed fluorescent probe exhibited high selectivity for pH over other metal ions and amino acids. Meanwhile, the carbon-dots-based inorganic-organic probe demonstrated excellent photostability against long-term light illumination. In order to study the extracellular pH change in processes of cell proliferation and metabolism, CD@Nile-FITC probe was entrapped in sodium alginate gel and consequently formed CD@Nile-FITC@Gel. The MTT assay showed low cytotoxicity of the Gel and the pH titration indicated that it could monitor the pH fluctuations linearly and rapidly within the pH range of 6.0-9.0, which is valuable for physiological pH determination. As expected, the real-time bioimaging of the probe was successfully achieved. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Integration and validation testing for PhEDEx, DBS and DAS with the PhEDEx LifeCycle agent

    CERN Document Server

    Wildish, Anthony

    2013-01-01

    The ever-increasing amount of data handled by the CMS dataflow and workflow management tools poses new challenges for cross-validation among different systems within CMS experiment at LHC. To approach this problem we developed an integration test suite based on the LifeCycle agent, a tool originally conceived for stress-testing new releases of PhEDEx, the CMS data-placement tool. The LifeCycle agent provides a framework for customising the test workflow in arbitrary ways, and can scale to levels of activity well beyond those seen in normal running. This means we can run realistic performance tests at scales not likely to be seen by the experiment for some years, or with custom topologies to examine particular situations that may cause concern some time in the future.The LifeCycle agent has recently been enhanced to become a general purpose integration and validation testing tool for major CMS services (PhEDEx, DBS, DAS). It allows cross-system integration tests of all three components to be performed in contr...

  13. Development of phased-array ultrasonic testing probe

    International Nuclear Information System (INIS)

    Kawanami, Seiichi; Kurokawa, Masaaki; Taniguchi, Masaru; Tada, Yoshihisa

    2001-01-01

    Phased-array ultrasonic testing was developed for nondestructive evaluation of power plants. Phased-array UT scans and focuses an ultrasonic beam to inspect areas difficult to inspect by conventional UT. We developed a highly sensitive piezoelectric composite, and designed optimized phased-array UT probes. We are applying our phased-array UT to different areas of power plants. (author)

  14. Design and Calibration Tests of an Active Sound Intensity Probe

    Directory of Open Access Journals (Sweden)

    Thomas Kletschkowski

    2008-01-01

    Full Text Available The paper presents an active sound intensity probe that can be used for sound source localization in standing wave fields. The probe consists of a sound hard tube that is terminated by a loudspeaker and an integrated pair of microphones. The microphones are used to decompose the standing wave field inside the tube into its incident and reflected part. The latter is cancelled by an adaptive controller that calculates proper driving signals for the loudspeaker. If the open end of the actively controlled tube is placed close to a vibrating surface, the radiated sound intensity can be determined by measuring the cross spectral density between the two microphones. A one-dimensional free field can be realized effectively, as first experiments performed on a simplified test bed have shown. Further tests proved that a prototype of the novel sound intensity probe can be calibrated.

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

    Science.gov (United States)

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

    1997-01-01

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

  16. A gold nanocluster-based fluorescent probe for simultaneous pH and temperature sensing and its application to cellular imaging and logic gates

    Science.gov (United States)

    Wu, Yun-Tse; Shanmugam, Chandirasekar; Tseng, Wei-Bin; Hiseh, Ming-Mu; Tseng, Wei-Lung

    2016-05-01

    Metal nanocluster-based nanomaterials for the simultaneous determination of temperature and pH variations in micro-environments are still a challenge. In this study, we develop a dual-emission fluorescent probe consisting of bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs) and fluorescein-5-isothiocyanate (FITC) as temperature- and pH-responsive fluorescence signals. Under single wavelength excitation the FITC/BSA-AuNCs exhibited well-separated dual emission bands at 525 and 670 nm. When FITC was used as a reference fluorophore, FITC/BSA-AuNCs showed a good linear response over the temperature range 1-71 °C and offered temperature-independent spectral shifts, temperature accuracy, activation energy, and reusability. The possible mechanism for high temperature-induced fluorescence quenching of FITC/BSA-AuNCs could be attributed to a weakening of the Au-S bond, thereby lowering the charge transfer from BSA to AuNCs. Additionally, the pH- and temperature-responsive properties of FITC/BSA-AuNCs allow simultaneous temperature sensing from 21 to 41 °C (at intervals of 5 °C) and pH from 6.0 to 8.0 (at intervals of 0.5 pH unit), facilitating the construction of two-input AND logic gates. Three-input AND logic gates were also designed using temperature, pH, and trypsin as inputs. The practicality of using FITC/BSA-AuNCs to determine the temperature and pH changes in HeLa cells is also validated.Metal nanocluster-based nanomaterials for the simultaneous determination of temperature and pH variations in micro-environments are still a challenge. In this study, we develop a dual-emission fluorescent probe consisting of bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs) and fluorescein-5-isothiocyanate (FITC) as temperature- and pH-responsive fluorescence signals. Under single wavelength excitation the FITC/BSA-AuNCs exhibited well-separated dual emission bands at 525 and 670 nm. When FITC was used as a reference fluorophore, FITC/BSA-AuNCs showed a

  17. Smartphone-Based pH Sensor for Home Monitoring of Pulmonary Exacerbations in Cystic Fibrosis.

    Science.gov (United States)

    Sun, Alexander; Phelps, Tom; Yao, Chengyang; Venkatesh, A G; Conrad, Douglas; Hall, Drew A

    2017-05-30

    Currently, Cystic Fibrosis (CF) patients lack the ability to track their lung health at home, relying instead on doctor checkups leading to delayed treatment and lung damage. By leveraging the ubiquity of the smartphone to lower costs and increase portability, a smartphone-based peripheral pH measurement device was designed to attach directly to the headphone port to harvest power and communicate with a smartphone application. This platform was tested using prepared pH buffers and sputum samples from CF patients. The system matches within ~0.03 pH of a benchtop pH meter while fully powering itself and communicating with a Samsung Galaxy S3 smartphone paired with either a glass or Iridium Oxide (IrOx) electrode. The IrOx electrodes were found to have 25% higher sensitivity than the glass probes at the expense of larger drift and matrix sensitivity that can be addressed with proper calibration. The smartphone-based platform has been demonstrated as a portable replacement for laboratory pH meters, and supports both highly robust glass probes and the sensitive and miniature IrOx electrodes with calibration. This tool can enable more frequent pH sputum tracking for CF patients to help detect the onset of pulmonary exacerbation to provide timely and appropriate treatment before serious damage occurs.

  18. Pico Reentry Probes: Affordable Options for Reentry Measurements and Testing

    Science.gov (United States)

    Ailor, William H.; Kapoor, Vinod B.; Allen, Gay A., Jr.; Venkatapathy, Ethiraj; Arnold, James O.; Rasky, Daniel J.

    2005-01-01

    It is generally very costly to perform in-space and atmospheric entry experiments. This paper presents a new platform - the Pico Reentry Probe (PREP) - that we believe will make targeted flight-tests and planetary atmospheric probe science missions considerably more affordable. Small, lightweight, self-contained, it is designed as a "launch and forget" system, suitable for experiments that require no ongoing communication with the ground. It contains a data recorder, battery, transmitter, and user-customized instrumentation. Data recorded during reentry or space operations is returned at end-of-mission via transmission to Iridium satellites (in the case of earth-based operations) or a similar orbiting communication system for planetary missions. This paper discusses possible applications of this concept for Earth and Martian atmospheric entry science. Two well-known heritage aerodynamic shapes are considered as candidates for PREP: the shape developed for the Planetary Atmospheric Experiment Test (PAET) and that for the Deep Space II Mars Probe.

  19. Tuning the probe location on zwitterionic micellar system with variation of pH and addition of surfactants with different alkyl chains: solvent and rotational relaxation studies.

    Science.gov (United States)

    Banerjee, Chiranjib; Mandal, Sarthak; Ghosh, Surajit; Rao, Vishal Govind; Sarkar, Nilmoni

    2012-09-13

    In this manuscript, we have modulated the location of an anionic probe, Coumarin-343 (C-343) in a zwitterionic (N-hexadecyl-N,N-dimethylammonio-1-propanesulfonate (SB-16)) micellar system by three different approaches. The effect of addition of the surfactant sodium dodecyl sulfate (SDS) and the room temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium octylsulfate (EmimOs) and N,N-dimethylethanol hexanoate (DAH), to the micellar solution has been studied. The effect of pH variation has been studied as well using solvent and rotational measurements. Migration of the anionic probe, C-343, from the palisade layer of SB-16 micelle to the bulk water has been observed to varying extents with the addition of SDS and EmimOs. The effect is much more pronounced in the presence of SDS and can be ascribed to the presence of the long alkyl (dodecyl) chain on SDS which can easily orient itself and fuse inside the SB-16 micelle and facilitate the observed migration of the probe molecule. This phenomenon is confirmed by faster solvation and rotational relaxation of the investigated probe molecule. The analogous fusion process is difficult in case of EmimOs and DAH because of their comparatively smaller alkyl (octyl and hexanoate) chain. However, the direction of C-343 migration is reversed with the decrease of pH of the SB-16 micellar medium. An increase in the average solvation and rotational relaxation time of the probe in acidic medium has been observed. Since experimental conditions are maintained such that the probe molecules and the zwitterionic SB-16 micelles remain oppositely charged, the observed results can be attributed to the increased electrostatic interaction (attractive) between them. Temperature dependent study also supports this finding.

  20. Impact of Probe Placement Error on MIMO OTA Test Zone Performance

    DEFF Research Database (Denmark)

    Fan, Wei; Nielsen, Jesper Ødum; Carreño, Xavier

    2012-01-01

    Standardization work for MIMO OTA testing methods is currently ongoing, where a multi-probe anechoic chamber based solution is an important candidate. In this paper, the probes located on an OTA ring are used to synthesize a plane wave field in the center of the OTA ring, and the EM field for each...

  1. Coherent evolution of parahydrogen induced polarisation using laser pump, NMR probe spectroscopy: Theoretical framework and experimental observation.

    Science.gov (United States)

    Halse, Meghan E; Procacci, Barbara; Henshaw, Sarah-Louise; Perutz, Robin N; Duckett, Simon B

    2017-05-01

    We recently reported a pump-probe method that uses a single laser pulse to introduce parahydrogen (p-H 2 ) into a metal dihydride complex and then follows the time-evolution of the p-H 2 -derived nuclear spin states by NMR. We present here a theoretical framework to describe the oscillatory behaviour of the resultant hyperpolarised NMR signals using a product operator formalism. We consider the cases where the p-H 2 -derived protons form part of an AX, AXY, AXYZ or AA'XX' spin system in the product molecule. We use this framework to predict the patterns for 2D pump-probe NMR spectra, where the indirect dimension represents the evolution during the pump-probe delay and the positions of the cross-peaks depend on the difference in chemical shift of the p-H 2 -derived protons and the difference in their couplings to other nuclei. The evolution of the NMR signals of the p-H 2 -derived protons, as well as the transfer of hyperpolarisation to other NMR-active nuclei in the product, is described. The theoretical framework is tested experimentally for a set of ruthenium dihydride complexes representing the different spin systems. Theoretical predictions and experimental results agree to within experimental error for all features of the hyperpolarised 1 H and 31 P pump-probe NMR spectra. Thus we establish the laser pump, NMR probe approach as a robust way to directly observe and quantitatively analyse the coherent evolution of p-H 2 -derived spin order over micro-to-millisecond timescales. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Results and Conclusions from the NASA Isokinetic Total Water Content Probe 2009 IRT Test

    Science.gov (United States)

    Reehorst, Andrew; Brinker, David

    2010-01-01

    The NASA Glenn Research Center has developed and tested a Total Water Content Isokinetic Sampling Probe. Since, by its nature, it is not sensitive to cloud water particle phase nor size, it is particularly attractive to support super-cooled large droplet and high ice water content aircraft icing studies. The instrument comprises the Sampling Probe, Sample Flow Control, and Water Vapor Measurement subsystems. Results and conclusions are presented from probe tests in the NASA Glenn Icing Research Tunnel (IRT) during January and February 2009. The use of reference probe heat and the control of air pressure in the water vapor measurement subsystem are discussed. Several run-time error sources were found to produce identifiable signatures that are presented and discussed. Some of the differences between measured Isokinetic Total Water Content Probe and IRT calibration seems to be caused by tunnel humidification and moisture/ice crystal blow around. Droplet size, airspeed, and liquid water content effects also appear to be present in the IRT calibration. Based upon test results, the authors provide recommendations for future Isokinetic Total Water Content Probe development.

  3. 21 CFR 862.1120 - Blood gases (PCO2, PO2) and blood pH test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Blood gases (PCO2, PO2) and blood pH test system... Test Systems § 862.1120 Blood gases (PCO2, PO2) and blood pH test system. (a) Identification. A blood gases (PCO2, PO2) and blood pH test system is a device intended to measure certain gases in blood, serum...

  4. Characterization of Growing Soil Bacterial Communities across a pH gradient Using H218O DNA-Stable Isotope Probing

    Science.gov (United States)

    Welty-Bernard, A. T.; Schwartz, E.

    2014-12-01

    Recent studies have established consistent relationships between pH and bacterial diversity and community structure in soils from site-specific to landscape scales. However, these studies rely on DNA or PLFA extraction techniques from bulk soils that encompass metabolically active and inactive, or dormant, communities, and loose DNA. Dormant cells may comprise up to 80% of total live cells. If dormant cells dominate a particular environment, it is possible that previous interpretations of the soil variables assumed to drive communities could be profoundly affected. We used H218O stable isotope probing and bar-coded illumina sequencing of 16S rRNA genes to monitor the response of actively growing communities to changes in soil pH in a soil microcosm over 14 days. This substrate-independent approach has several advantages over 13C or 15N-labelled molecules in that all growing bacteria should be able to make use of water, allowing characterization of whole communities. We hypothesized that Acidobacteria would increasingly dominate the growing community and that Actinobacteria and Bacteroidetes would decline, given previously established responses by these taxa to soil pH. Instead, we observed the reverse. Actinobacteria abundance increased three-fold from 26 to 76% of the overall community as soil pH fell from pH 5.6 to pH 4.6. Shifts in community structure and decreases in diversity with declining soil pH were essentially driven by two families, Streptomyceaca and Microbacteracea, which collectively increased from 2 to 40% of the entire community. In contrast, Acidobacteria as a whole declined although numbers of subdivision 1 remained stable across all soil pH levels. We suggest that the brief incubation period in this SIP study selected for growth of acid-tolerant Actinobacteria over Acidobacteria. Taxa within Actinomycetales have been readily cultured over short time frames, suggesting rapid growth patterns. Conversely, taxa within Acidobacteria have been

  5. Sensitive detection of strong acidic condition by a novel rhodamine-based fluorescent pH chemosensor.

    Science.gov (United States)

    Tan, Jia-Lian; Yang, Ting-Ting; Liu, Yu; Zhang, Xue; Cheng, Shu-Jin; Zuo, Hua; He, Huawei

    2016-05-01

    A novel rhodamine-based fluorescent pH probe responding to extremely low pH values has been synthesized and characterized. This probe showed an excellent photophysical response to pH on the basis that the colorless spirocyclic structure under basic conditions opened to a colored and highly fluorescent form under extreme acidity. The quantitative relationship between fluorescence intensity and pH value (1.75-2.62) was consistent with the equilibrium equation pH = pKa + log[(Imax - I)/(I - Imin)]. This sensitive pH probe was also characterized with good reversibility and no interaction with interfering metal ions, and was successfully applied to image Escherichia coli under strong acidity. Copyright © 2015 John Wiley & Sons, Ltd.

  6. Design and test of voltage and current probes for EAST ICRF antenna impedance measurement

    Science.gov (United States)

    Jianhua, WANG; Gen, CHEN; Yanping, ZHAO; Yuzhou, MAO; Shuai, YUAN; Xinjun, ZHANG; Hua, YANG; Chengming, QIN; Yan, CHENG; Yuqing, YANG; Guillaume, URBANCZYK; Lunan, LIU; Jian, CHENG

    2018-04-01

    On the experimental advanced superconducting tokamak (EAST), a pair of voltage and current probes (V/I probes) is installed on the ion cyclotron radio frequency transmission lines to measure the antenna input impedance, and supplement the conventional measurement technique based on voltage probe arrays. The coupling coefficients of V/I probes are sensitive to their sizes and installing locations, thus they should be determined properly to match the measurement range of data acquisition card. The V/I probes are tested in a testing platform at low power with various artificial loads. The testing results show that the deviation of coupling resistance is small for loads R L > 2.5 Ω, while the resistance deviations appear large for loads R L phase measurement error is the more significant factor leads to deleterious results rather than the amplitude measurement error. To exclude the possible ingredients that may lead to phase measurement error, the phase detector can be calibrated in steady L-mode scenario and then use the calibrated data for calculation under H-mode cases in EAST experiments.

  7. Verification of Emulated Channels in Multi-Probe Based MIMO OTA Testing Setup

    DEFF Research Database (Denmark)

    Fan, Wei; Carreño, Xavier; Nielsen, Jesper Ødum

    2013-01-01

    Standardization work for MIMO OTA testing methods is currently ongoing, where a multi-probe anechoic chamber based solution is an important candidate. In this paper, the probes located on an OTA ring are used to synthesize a plane wave field in the center of the OTA ring. This paper investigates...

  8. Imaging Lysosomal pH Alteration in Stressed Cells with a Sensitive Ratiometric Fluorescence Sensor.

    Science.gov (United States)

    Xue, Zhongwei; Zhao, Hu; Liu, Jian; Han, Jiahuai; Han, Shoufa

    2017-03-24

    The organelle-specific pH is crucial for cell homeostasis. Aberrant pH of lysosomes has been manifested in myriad diseases. To probe lysosome responses to cell stress, we herein report the detection of lysosomal pH changes with a dual colored probe (CM-ROX), featuring a coumarin domain with "always-on" blue fluorescence and a rhodamine-lactam domain activatable to lysosomal acidity to give red fluorescence. With sensitive ratiometric signals upon subtle pH changes, CM-ROX enables discernment of lysosomal pH changes in cells undergoing autophagy, cell death, and viral infection.

  9. Raman probe. Innovative technology summary report

    International Nuclear Information System (INIS)

    1999-07-01

    The Raman probe is deployed in high-level waste tanks with the cone penetrometer (CPT). These technologies are engineered and optimized to work together. All of the hardware is radiation hardened, designed for and tested in the high-radiation, highly caustic chemical environment of US Department of Energy's (DOE's) waste storage tanks. When deployed in tanks, the system is useful for rapidly assessing the species and concentrations of organic-bearing tank wastes. The CPT was originally developed for geological and groundwater applications, with sensors that measure physical parameters such as soil moisture, temperature, and pH. When deployed, it is hydraulically forced directly into the ground rather than using boring techniques utilized by rotary drilling systems. There is a separate Innovative Technology Summary Report for the CPT, so this report will focus on the changes made specifically to support the Raman probe. The most significant changes involve adapting the Raman probe for in-tank and subsurface field use and developing meaningful real-time data analysis. Testing of the complete LLNL system was conducted in a hot cell in the 222-S Laboratory at the Hanford site in summer 1997. Both instruments were tested in situ on solvent-contaminated soils (TCE and PCE) at the Savannah River Site in February and June 1998. This report describes the technology, its performance, its uses, cost, regulatory and policy issues, and lessons learned

  10. A gold nanocluster-based fluorescent probe for simultaneous pH and temperature sensing and its application to cellular imaging and logic gates.

    Science.gov (United States)

    Wu, Yun-Tse; Shanmugam, Chandirasekar; Tseng, Wei-Bin; Hiseh, Ming-Mu; Tseng, Wei-Lung

    2016-06-07

    Metal nanocluster-based nanomaterials for the simultaneous determination of temperature and pH variations in micro-environments are still a challenge. In this study, we develop a dual-emission fluorescent probe consisting of bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs) and fluorescein-5-isothiocyanate (FITC) as temperature- and pH-responsive fluorescence signals. Under single wavelength excitation the FITC/BSA-AuNCs exhibited well-separated dual emission bands at 525 and 670 nm. When FITC was used as a reference fluorophore, FITC/BSA-AuNCs showed a good linear response over the temperature range 1-71 °C and offered temperature-independent spectral shifts, temperature accuracy, activation energy, and reusability. The possible mechanism for high temperature-induced fluorescence quenching of FITC/BSA-AuNCs could be attributed to a weakening of the Au-S bond, thereby lowering the charge transfer from BSA to AuNCs. Additionally, the pH- and temperature-responsive properties of FITC/BSA-AuNCs allow simultaneous temperature sensing from 21 to 41 °C (at intervals of 5 °C) and pH from 6.0 to 8.0 (at intervals of 0.5 pH unit), facilitating the construction of two-input AND logic gates. Three-input AND logic gates were also designed using temperature, pH, and trypsin as inputs. The practicality of using FITC/BSA-AuNCs to determine the temperature and pH changes in HeLa cells is also validated.

  11. [Diagnosis of human brucellosis. Role of pH in the seroagglutination test and influence of pH on the agglutinating activity of IgM, IgG and IgA antibodies].

    Science.gov (United States)

    Rubio Vallejo, Manuel; del Pozo, José L; Del Pozo León, José Luis; Hernández-Molina, Juan Manuel; Dorronsoro Ibero, Inés; Marrodán Ciordia, Teresa; Díaz García, Ramón

    2002-04-01

    To evaluate the role of pH in the seroagglutination test (SAT)and Rose Bengal (RB) test, and to determine the influence of pH on the agglutinating activity of IgM, IgG and IgA antibodies. The SAT was performed at pH 7.2 or pH 5.0 in standard microtiter-type polystyrene plates using Ring Test antigen or the Brucella suspension (BRUCAPT) provided in the Brucellacapt kits. Specific antibodies against native hapten were determined by radial immunodiffusion. Additionally, IgG, IgA and IgM fractions were separated from 8 sera by absorption chromatography and their agglutinating capacity was studied at pH 7.2 and 5.0. We studied 72 sera from patients with clinical brucellosis taken at the time of hospitalization, 16 from persons in contact with infected animals, and 16 from healthy donors. SAT results at pH 5.0 correlated with those obtained with the Rose Bengal test. Four Rose Bengal-positive sera were found to be SAT-negative at pH 7.2 and SAT-positive at pH 5.0. SAT performed at pH 5.0 with BRUCAPT antigen yielded higher titers than tests performed at pH 7.2 or 5.0 with Ring Test antigen (p IgA fractions were SAT-negative at pH 7.2 and SAT-positive at pH 5.0; the other 5 agglutinated at both pH conditions and were DTT-sensitive. All IgA fractions but one were positive by Rose Bengal. Agglutinating activity of the IgM fraction was not affected by pH. The SAT performed with the buffer and antigen suspension included in the Brucellacapt kit (pH 5.0) is highly useful for detecting agglutinating and non-agglutinating antibodies at pH 7.2.

  12. Stand-Alone Containment Analysis of the Phébus FPT Tests with the ASTEC and the MELCOR Codes: The FPT-0 Test

    Directory of Open Access Journals (Sweden)

    Bruno Gonfiotti

    2017-01-01

    Full Text Available The integral Phébus tests were probably one of the most important experimental campaigns performed to investigate the progression of severe accidents in light water reactors. In these tests, the degradation of a PWR fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the results of such tests, numerical codes such as ASTEC and MELCOR have been developed to describe the evolution of a severe accident. After the termination of the experimental Phébus campaign, these two codes were furthermore expanded. Therefore, the aim of the present work is to reanalyze the first Phébus test (FPT-0 employing the updated ASTEC and MELCOR versions to ensure that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The analysis focuses on the stand-alone containment aspects of this test, and the paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products behavior. This paper is part of a series of publications covering the four executed Phébus tests employing a solid PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3.

  13. Manipulation of pH induced sensitivity of a fluorescent probe in presence of silver nanoparticles

    International Nuclear Information System (INIS)

    Kacmaz, Sibel; Ertekin, Kadriye; Oter, Ozlem; Hizliateş, Cevher Gundogdu; Ergun, Yavuz; Celik, Erdal

    2015-01-01

    In this study, pH induced spectral response of the newly synthesized carbazole derivative (9-butyl-bis-3-(4-(dimethylamino) phenyl) allylidene)-9H-carbazole-3,6-diamine) has been declared. We utilized silver nanoparticles (AgNPs) along with ionic liquid as additives for manipulation of the spectral response. Plasticized ethyl cellulose (EC) was used as matrix material. Fibers and porous films were produced by electrospinning technique. The emission intensity at 631 nm has been followed as the analytical signal. Utilization of silver nanoparticles in electrospun polymeric fibers for pH sensing purposes resulted with many advantages such as tuned sensitivity, linear calibration plot for larger pH ranges, increased surface area and enhancement in all sensor dynamics. Additionally, we performed manipulation of the pKa within the same matrix exploiting the silver NPs. Characteristics of the pH induced response for the offered composition was superior with respect to the previously reported ones. When stored at the ambient air of the laboratory there was no significant drift in the signal intensity after 16 months. Our sensitivity and stability tests are still in progress. - Highlights: • A carbozole derivative was used for the first time for sensing of pH along with silver nanoparticles. • The sensor slides fabricated in form of nanofibers. • The Ag containing and Ag-free slides were produced by electrospinning technique. • pH Sensitivity of the dye was compared for both; Ag containing and Ag-free forms. • We performed manipulation of the pKa within the same matrix exploiting the silver NPs.

  14. Manipulation of pH induced sensitivity of a fluorescent probe in presence of silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kacmaz, Sibel [Giresun University, Faculty of Engineering, Department of Food Engineering, 28200 Giresun (Turkey); Ertekin, Kadriye [University of Dokuz Eylul, Faculty of Sciences, Department of Chemistry, 35160 Izmir (Turkey); University of Dokuz Eylul, Center for Fabrication and Application of Electronic Materials (EMUM), 35160 Izmir (Turkey); Oter, Ozlem; Hizliateş, Cevher Gundogdu; Ergun, Yavuz [University of Dokuz Eylul, Faculty of Sciences, Department of Chemistry, 35160 Izmir (Turkey); Celik, Erdal [University of Dokuz Eylul, Faculty of Engineering, Department of Metallurgical and Materials Engineering, 35160 Izmir (Turkey); University of Dokuz Eylul, Center for Fabrication and Application of Electronic Materials (EMUM), 35160 Izmir (Turkey)

    2015-12-15

    In this study, pH induced spectral response of the newly synthesized carbazole derivative (9-butyl-bis-3-(4-(dimethylamino) phenyl) allylidene)-9H-carbazole-3,6-diamine) has been declared. We utilized silver nanoparticles (AgNPs) along with ionic liquid as additives for manipulation of the spectral response. Plasticized ethyl cellulose (EC) was used as matrix material. Fibers and porous films were produced by electrospinning technique. The emission intensity at 631 nm has been followed as the analytical signal. Utilization of silver nanoparticles in electrospun polymeric fibers for pH sensing purposes resulted with many advantages such as tuned sensitivity, linear calibration plot for larger pH ranges, increased surface area and enhancement in all sensor dynamics. Additionally, we performed manipulation of the pKa within the same matrix exploiting the silver NPs. Characteristics of the pH induced response for the offered composition was superior with respect to the previously reported ones. When stored at the ambient air of the laboratory there was no significant drift in the signal intensity after 16 months. Our sensitivity and stability tests are still in progress. - Highlights: • A carbozole derivative was used for the first time for sensing of pH along with silver nanoparticles. • The sensor slides fabricated in form of nanofibers. • The Ag containing and Ag-free slides were produced by electrospinning technique. • pH Sensitivity of the dye was compared for both; Ag containing and Ag-free forms. • We performed manipulation of the pKa within the same matrix exploiting the silver NPs.

  15. Vaginal pH: Home-Use Tests

    Science.gov (United States)

    ... doesn't always mean that you have a vaginal infection. pH changes also do not help or differentiate ... of infection from another. Your doctor diagnoses a vaginal infection by using a combination of: pH, microscopic examination ...

  16. Dependence of Error Level on the Number of Probes in Over-the-Air Multiprobe Test Systems

    Directory of Open Access Journals (Sweden)

    Afroza Khatun

    2012-01-01

    Full Text Available Development of MIMO over-the-air (OTA test methodology is ongoing. Several test methods have been proposed. Anechoic chamber-based multiple-probe technique is one promising candidate for MIMO-OTA testing. The required number of probes for synthesizing the desired fields inside the multiprobe system is an important issue as it has a large impact on the cost of the test system. In this paper, we review the existing investigations on this important topic and end up presenting rules for the required number of probes as a function of the test zone size in wavelengths for certain chosen uncertainty levels of the field synthesis.

  17. Distinguishing normal cells from cancer cells via lysosome-targetable pH biomarkers with benzo[a]phenoxazine skeleton

    Energy Technology Data Exchange (ETDEWEB)

    Zhan, Yan-Hua [College of Chemistry, Chemical Engineering and Material Science, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Soochow University, 199 Ren’Ai Road, Suzhou, 215123 (China); Li, Xiao-Jun [School of Radiation Medicine and Protection, Medicine College of Soochow University, Suzhou, 215123 (China); Sun, Ru, E-mail: sunru924@hotmail.com [College of Chemistry, Chemical Engineering and Material Science, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Soochow University, 199 Ren’Ai Road, Suzhou, 215123 (China); Xu, Yu-Jie [School of Radiation Medicine and Protection, Medicine College of Soochow University, Suzhou, 215123 (China); Ge, Jian-Feng, E-mail: ge_jianfeng@hotmail.com [College of Chemistry, Chemical Engineering and Material Science, State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Soochow University, 199 Ren’Ai Road, Suzhou, 215123 (China); Jiangsu Key Laboratory of Medical Optics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163 (China)

    2016-08-24

    In this paper, the design of a lysosome-targetable pH probe that has a fluorescent OFF (pH = 4) to ON (pH = 5–6) response is described to identify lysosomes in normal cells. The mechanism of photoinduced electron transfer with a fluorophore-based reaction (FBR-PET) was proposed. Benzo[a]phenoxazines with electro-donating aryl groups were selected, its (2,5-dimethoxyphenyl)imino-, (2-hydroxyphenyl)imino- and (2-hydroxy-5-methoxyphenyl)- imino-derivatives (probes 1a−c) were prepared and their optical responses towards pH were evaluated; their fluorescence pH titration experiments gave regularly changes with the increasing electro-donating abilities at the linked aryl groups, the (2-hydroxy-5-methoxyphenyl)iminobenzo[a]phenoxazine (probe 1c) exhibited a nearly OFF−ON response at 580–800 nm. All probes were reversible, and they showed excellent selectivity toward the proton over other competitive species. Fluorescence confocal images were performed with HeLa, KB cancer cells and V79 normal cells, probes 1a−c are all lysosome-targetable pH probes, and benzo[a]phenoxazine with (2-hydroxy-5-methoxyphenyl)imino-group (probe 1c) has potential applications in selective differentiation of normal cells from cancer cells. - Highlights: • pH probes for lysosome detection in normal cells. • Differentiation of normal cells from cancer cells by lysosome-biomarker. • The PET mechanism promoted by fluorophore based reactions (FBR-PET).

  18. Distinguishing normal cells from cancer cells via lysosome-targetable pH biomarkers with benzo[a]phenoxazine skeleton

    International Nuclear Information System (INIS)

    Zhan, Yan-Hua; Li, Xiao-Jun; Sun, Ru; Xu, Yu-Jie; Ge, Jian-Feng

    2016-01-01

    In this paper, the design of a lysosome-targetable pH probe that has a fluorescent OFF (pH = 4) to ON (pH = 5–6) response is described to identify lysosomes in normal cells. The mechanism of photoinduced electron transfer with a fluorophore-based reaction (FBR-PET) was proposed. Benzo[a]phenoxazines with electro-donating aryl groups were selected, its (2,5-dimethoxyphenyl)imino-, (2-hydroxyphenyl)imino- and (2-hydroxy-5-methoxyphenyl)- imino-derivatives (probes 1a−c) were prepared and their optical responses towards pH were evaluated; their fluorescence pH titration experiments gave regularly changes with the increasing electro-donating abilities at the linked aryl groups, the (2-hydroxy-5-methoxyphenyl)iminobenzo[a]phenoxazine (probe 1c) exhibited a nearly OFF−ON response at 580–800 nm. All probes were reversible, and they showed excellent selectivity toward the proton over other competitive species. Fluorescence confocal images were performed with HeLa, KB cancer cells and V79 normal cells, probes 1a−c are all lysosome-targetable pH probes, and benzo[a]phenoxazine with (2-hydroxy-5-methoxyphenyl)imino-group (probe 1c) has potential applications in selective differentiation of normal cells from cancer cells. - Highlights: • pH probes for lysosome detection in normal cells. • Differentiation of normal cells from cancer cells by lysosome-biomarker. • The PET mechanism promoted by fluorophore based reactions (FBR-PET).

  19. Stand-alone containment analysis of Phébus FPT tests with ASTEC and MELCOR codes: the FPT-2 test.

    Science.gov (United States)

    Gonfiotti, Bruno; Paci, Sandro

    2018-03-01

    During the last 40 years, many studies have been carried out to investigate the different phenomena occurring during a Severe Accident (SA) in a Nuclear Power Plant (NPP). Such efforts have been supported by the execution of different experimental campaigns, and the integral Phébus FP tests were probably some of the most important experiments in this field. In these tests, the degradation of a Pressurized Water Reactor (PWR) fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the findings on these and previous tests, numerical codes such as ASTEC and MELCOR have been developed to analyze the evolution of a SA in real NPPs. After the termination of the Phébus FP campaign, these two codes have been furthermore improved to implement the more recent findings coming from different experimental campaigns. Therefore, continuous verification and validation is still necessary to check that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The aim of the present work is to re-analyze the Phébus FPT-2 test employing the updated ASTEC and MELCOR code versions. The analysis focuses on the stand-alone containment aspects of this test, and three different spatial nodalizations of the containment vessel (CV) have been developed. The paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products (FP) behavior. When possible, a comparison among the results obtained during this work and by different authors in previous work is also performed. This paper is part of a series of publications covering the four Phébus FP tests using a PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3, excluding the FPT-4 one, related to the study of the release of low-volatility FP and transuranic elements from a debris bed and a pool of melted fuel.

  20. Stand-alone containment analysis of Phébus FPT tests with ASTEC and MELCOR codes: the FPT-2 test

    Directory of Open Access Journals (Sweden)

    Bruno Gonfiotti

    2018-03-01

    Full Text Available During the last 40 years, many studies have been carried out to investigate the different phenomena occurring during a Severe Accident (SA in a Nuclear Power Plant (NPP. Such efforts have been supported by the execution of different experimental campaigns, and the integral Phébus FP tests were probably some of the most important experiments in this field. In these tests, the degradation of a Pressurized Water Reactor (PWR fuel bundle was investigated employing different control rod materials and burn-up levels in strongly or weakly oxidizing conditions. From the findings on these and previous tests, numerical codes such as ASTEC and MELCOR have been developed to analyze the evolution of a SA in real NPPs. After the termination of the Phébus FP campaign, these two codes have been furthermore improved to implement the more recent findings coming from different experimental campaigns. Therefore, continuous verification and validation is still necessary to check that the new improvements introduced in such codes allow also a better prediction of these Phébus tests. The aim of the present work is to re-analyze the Phébus FPT-2 test employing the updated ASTEC and MELCOR code versions. The analysis focuses on the stand-alone containment aspects of this test, and three different spatial nodalizations of the containment vessel (CV have been developed. The paper summarizes the main thermal-hydraulic results and presents different sensitivity analyses carried out on the aerosols and fission products (FP behavior. When possible, a comparison among the results obtained during this work and by different authors in previous work is also performed. This paper is part of a series of publications covering the four Phébus FP tests using a PWR fuel bundle: FPT-0, FPT-1, FPT-2, and FPT-3, excluding the FPT-4 one, related to the study of the release of low-volatility FP and transuranic elements from a debris bed and a pool of melted fuel. Keywords: Safety

  1. Probing Minicharged Particles with Tests of Coulomb's Law

    International Nuclear Information System (INIS)

    Jaeckel, Joerg

    2009-01-01

    Minicharged particles arise in many extensions of the standard model. Their contribution to the vacuum polarization modifies Coulomb's law via the Uehling potential. In this Letter, we argue that tests for electromagnetic fifth forces can therefore be a sensitive probe of minicharged particles. In the low mass range < or approx. μeV existing constraints from Cavendish type experiments provide the best model-independent bounds on minicharged particles.

  2. Continuous waves probing in dynamic acoustoelastic testing

    Science.gov (United States)

    Scalerandi, M.; Gliozzi, A. S.; Ait Ouarabi, M.; Boubenider, F.

    2016-05-01

    Consolidated granular media display a peculiar nonlinear elastic behavior, which is normally analysed with dynamic ultrasonic testing exploiting the dependence on amplitude of different measurable quantities, such as the resonance frequency shift, the amount of harmonics generation, or the break of the superposition principle. However, dynamic testing allows measuring effects which are averaged over one (or more) cycles of the exciting perturbation. Dynamic acoustoelastic testing has been proposed to overcome this limitation and allow the determination of the real amplitude dependence of the modulus of the material. Here, we propose an implementation of the approach, in which the pulse probing waves are substituted by continuous waves. As a result, instead of measuring a time-of-flight as a function of the pump strain, we study the dependence of the resonance frequency on the strain amplitude, allowing to derive the same conclusions but with an easier to implement procedure.

  3. HTI CONE PENETROMETER PROBES PREPARATION DEVELOPMENTAL TESTING REPORT

    Energy Technology Data Exchange (ETDEWEB)

    IWATATE, D.F.

    1998-10-26

    The HTI subsurface characterization task will use the Hanford Cone Penetrometer platform (CPP) to deploy soil sensor and sampling probes into the vadose zone/soils around AX-104 during FY-99. This report provides the data and information compiled during vendor field development tests and laboratory/bench checkout. This document is a vendor deliverable item identified in the ARA Statement of Work HNF-2881, Revision 1. This version of the DTR includes to-be-determined items and some incomplete sections. The Rev. 0 is being released to support the concurrent task of procedure preparation and Qualification Test Plan preparation. Revision 1 is planned to contain all data and information.

  4. Standard test method for measuring pH of soil for use in corrosion testing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1995-01-01

    1.1 This test method covers a procedure for determining the pH of a soil in corrosion testing. The principle use of the test is to supplement soil resistivity measurements and thereby identify conditions under which the corrosion of metals in soil may be accentuated (see G 57 - 78 (1984)). 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  5. Eddy current testing probe optimization using a parallel genetic algorithm

    Directory of Open Access Journals (Sweden)

    Dolapchiev Ivaylo

    2008-01-01

    Full Text Available This paper uses the developed parallel version of Michalewicz's Genocop III Genetic Algorithm (GA searching technique to optimize the coil geometry of an eddy current non-destructive testing probe (ECTP. The electromagnetic field is computed using FEMM 2D finite element code. The aim of this optimization was to determine coil dimensions and positions that improve ECTP sensitivity to physical properties of the tested devices.

  6. Measurements of spectral responses for developing fiber-optic pH sensor

    Science.gov (United States)

    Yoo, Wook Jae; Heo, Ji Yeon; Jang, Kyoung Won; Seo, Jeong Ki; Moon, Jin Soo; Park, Jang-Yeon; Park, Byung Gi; Cho, Seunghyun; Lee, Bongsoo

    2011-01-01

    In this study, we have fabricated a fiber-optic pH sensor, which is composed of a light source, a pH-sensing probe, plastic optical fibers and a spectrometer, for determining the degree of infection by Helicobacter pylori in the stomach. As pH indicators, phenol red and m-cresol purple are used, and pH liquid solutions are prepared by mixing phenol red or m-cresol purple solutions and various kinds of pH buffer solutions. The light emitted by a light source is guided by plastic optical fibers to the pH liquid solution, and the optical characteristic of a reflected light is changed according to the color variations of the pH indicator in the pH-sensing probe. Therefore, we have measured the intensities and wavelength shifts of the reflected lights, which change according to the color variations of indicators at different pH values, by using a spectrometer for spectral analysis. Also, the relationships between the pH values of liquid solutions and the optical properties of the modulated lights are obtained on the basis of the changes of the colors of indicators.

  7. Update to Millstone 3 elevated pH tests

    Energy Technology Data Exchange (ETDEWEB)

    Bergmann, C.A.; Perock, J.D. [Westinghouse Electric Corp., Pittsburgh, PA (United States); Hudson, M.J.B.; King, R.W.; Macklin, S. [Northeast Utilities, Hartford, CT (United States)

    1995-03-01

    In view of the potential radiological benefits of elevated coolant pH operation, Northwest Utilities (NU), in support of an EPRI-Westinghouse program, agreed to operate the Millstone 3 plant at the start of its second fuel cycle as a demonstration of the effect of elevated coolant pH on out-of-core radiation fields. Operating with an elevated pH is defined as operating with an average lithium concentration of 3.35 ppm, until reaching an end of cycle pH of 7.2 or 7.4. The plant operated during its second and third cycles with an elevated coolant pH. The end of cycle pH during the second cycle was 7.4, and 7.2 during the third cycle. (During the first cycle, operation was with a coordinated pH of 7.0). Evaluation of the dose rate trends in Millstone 3 after two cycles of elevated coolant pH operation concluded that an elevated coolant pH resulted in a 15 percent lower component dose rate compared to other plants that operated with coordinated pH 6.9. However, due to a possible increase in fuel clad corrosion, operation during cycle 4 was restricted to pH 6.9 coordinated chemistry, with the exception of the last two months during which the pH increased to 7.35. At the end of cycle 4 (EOC4), there was a greater increase in component and crud trap dose rates than expected. This paper reviews the radiological trends in the plant and discusses the potential causes for the increase in the dose rates at EOC4.

  8. Mitochondrial NAD(PH in vivo: identifying natural indicators of oxidative phosphorylation in the 31P magnetic resonance spectrum.

    Directory of Open Access Journals (Sweden)

    Kevin eConley

    2016-03-01

    Full Text Available Natural indicators provide intrinsic probes of metabolism, biogenesis and oxidative protection. Nicotinamide adenine dinucleotide metabolites (NAD(P are one class of indicators that have roles as co-factors in oxidative phosphorylation, glycolysis and anti-oxidant protection, as well as signaling in the mitochondrial biogenesis pathway. These many roles are made possible by the distinct redox states (NAD(P+ and NAD(PH, which are compartmentalized between cell and mitochondria. Here we provide evidence for detection of NAD(P+ and NAD(PH in separate mitochondrial and cell pools in vivo in human tissue by phosphorus magnetic resonance spectroscopy (31P MRS. These NAD(P pools are identified by chemical standards (NAD+, NADP+ and NADH and by physiological tests. A unique resonance reflecting mitochondrial NAD(PH is revealed by the changes elicited by elevation of mitochondrial oxidation. The decline of NAD(PH with oxidation is matched by a stoichiometric rise in the NAD(P+ peak. This unique resonance also provides a measure of the improvement in mitochondrial oxidation that parallels the greater phosphorylation found after exercise training in these elderly subjects. The implication is that the dynamics of the mitochondrial NAD(PH peak provides an intrinsic probe of the reversal of mitochondrial dysfunction in elderly muscle. Thus non-invasive detection of NAD(P+ and NAD(PH in cell vs. mitochondria yield natural indicators of redox compartmentalization and sensitive intrinsic probes of the improvement of mitochondrial function with an intervention in human tissues in vivo. These natural indicators hold the promise of providing mechanistic insight into metabolism and mitochondrial function in vivo in a range of tissues in health, disease and with treatment.

  9. Single-cell intracellular nano-pH probes.

    Science.gov (United States)

    Özel, Rıfat Emrah; Lohith, Akshar; Mak, Wai Han; Pourmand, Nader

    2015-01-01

    Within a large clonal population, such as cancerous tumor entities, cells are not identical, and the differences between intracellular pH levels of individual cells may be important indicators of heterogeneity that could be relevant in clinical practice, especially in personalized medicine. Therefore, the detection of the intracellular pH at the single-cell level is of great importance to identify and study outlier cells. However, quantitative and real-time measurements of the intracellular pH of individual cells within a cell population is challenging with existing technologies, and there is a need to engineer new methodologies. In this paper, we discuss the use of nanopipette technology to overcome the limitations of intracellular pH measurements at the single-cell level. We have developed a nano-pH probe through physisorption of chitosan onto hydroxylated quartz nanopipettes with extremely small pore sizes (~100 nm). The dynamic pH range of the nano-pH probe was from 2.6 to 10.7 with a sensitivity of 0.09 units. We have performed single-cell intracellular pH measurements using non-cancerous and cancerous cell lines, including human fibroblasts, HeLa, MDA-MB-231 and MCF-7, with the pH nanoprobe. We have further demonstrated the real-time continuous single-cell pH measurement capability of the sensor, showing the cellular pH response to pharmaceutical manipulations. These findings suggest that the chitosan-functionalized nanopore is a powerful nano-tool for pH sensing at the single-cell level with high temporal and spatial resolution.

  10. Nanoparticle assembled microcapsules for application as pH and ammonia sensor.

    Science.gov (United States)

    Amali, Arlin Jose; Awwad, Nour H; Rana, Rohit Kumar; Patra, Digambara

    2011-12-05

    The encapsulation of molecular probes in a suitable nanostructured matrix can be exploited to alter their optical properties and robustness for fabricating efficient chemical sensors. Despite high sensitivity, simplicity, selectivity and cost effectiveness, the photo-destruction and photo-bleaching are the serious concerns while utilizing molecular probes. Herein we demonstrate that hydroxy pyrene trisulfonate (HPTS), a pH sensitive molecular probe, when encapsulated in a microcapsule structure prepared via the assembly of silica nanoparticles mediated by poly-L-lysine and trisodium citrate, provides a robust sensing material for pH sensing under the physiological conditions. The temporal evolution under continuous irradiation indicates that the fluorophore inside the silica microcapsule is extraordinarily photostable. The fluorescence intensity alternation at dual excitation facilitates for a ratiometic sensing of the pH, however, the fluorescence lifetime is insensitive to hydrogen ion concentration. The sensing scheme is found to be robust, fast and simple for the measurement of pH in the range 5.8-8.0, and can be successfully applied for the determination of ammonia in the concentration range 0-1.2 mM, which is important for aquatic life and the environment. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Probing structural changes of self assembled i-motif DNA

    KAUST Repository

    Lee, Iljoon; Patil, Sachin; Fhayli, Karim; Alsaiari, Shahad K.; Khashab, Niveen M.

    2015-01-01

    We report an i-motif structural probing system based on Thioflavin T (ThT) as a fluorescent sensor. This probe can discriminate the structural changes of RET and Rb i-motif sequences according to pH change. This journal is

  12. ASSISTING STUDENTS TO ATTACK WRITING TASKS ON IELTS TEST WITH “PROBING TECHNIQUE”

    Directory of Open Access Journals (Sweden)

    Tedi Rohadi

    2015-06-01

    Full Text Available Writing section on IELTS test is commonly considered one of the most difficult parts of test. The test takers can’t even understand what to do with the tasks provided. They eventually write without clearly knowing the expected direction. Therefore, there should be a fastest way to well equip students to successfully cope with such hindrances. This paper is an action research report of how to make students better understand and answer writing tasks on IELTS test by employing probing techniques as one of test taking strategies. The paper will preliminarily elaborate the characteristics or nature of IELTS test in general and writing section consisting two different tasks in particular including its indicators of what expected kind of writing the testees should be aware of. It will then discuss probing techniques in details. The attack strategies and their sequential implementation will afterward be discussed. The technique will assist students to respectively understand what and how to plan and write effectively on the test.

  13. Methodologically controlled variations in laboratory and field pH measurements in waterlogged soils

    DEFF Research Database (Denmark)

    Elberling, Bo; Matthiesen, Henning

    2007-01-01

    artefacts is critical. But the study includes agricultural and forest soils for comparison. At a waterlogged site, Laboratory results were compared with three different field methods: calomel pH probes inserted in the soil from pits, pH measurements of soil solution extracted from the soil, and pH profiles...... using a solid-state pH electrode pushed into the soil from the surface. Comparisons between in situ and laboratory methods revealed differences of more than 1 pH unit. The content of dissolved ions in soil solution and field observations of O2 and CO2 concentrations were used in the speciation model...... PHREEQE in order to predict gas exchange processes. Changes in pH in soil solution following equilibrium in the laboratory could be explained mainly by CO2 degassing. Only soil pH measured in situ using either calomel or solid-state probes inserted directly into the soil was not affected by gas exchange...

  14. Nine New Fluorescent Probes

    Science.gov (United States)

    Lin, Tsung-I.; Jovanovic, Misa V.; Dowben, Robert M.

    1989-06-01

    Absorption and fluorescence spectroscopic studies are reported here for nine new fluorescent probes recently synthesized in our laboratories: four pyrene derivatives with substituents of (i) 1,3-diacetoxy-6,8-dichlorosulfonyl, (ii) 1,3-dihydroxy-6,8-disodiumsulfonate, (iii) 1,3-disodiumsulfonate, and (iv) l-ethoxy-3,6,8-trisodiumsulfonate groups, and five [7-julolidino] coumarin derivatives with substituents of (v) 3-carboxylate-4-methyl, (vi) 3- methylcarboxylate, (vii) 3-acetate-4-methyl, (viii) 3-propionate-4-methyl, and (ix) 3-sulfonate-4-methyl groups. Pyrene compounds i and ii and coumarin compounds v and vi exhibit interesting absorbance and fluorescence properties: their absorption maxima are red shifted compared to the parent compound to the blue-green region, and the band width broadens considerably. All four blue-absorbing dyes fluoresce intensely in the green region, and the two pyrene compounds emit at such long wavelengths without formation of excimers. The fluorescence properties of these compounds are quite environment-sensitive: considerable spectral shifts and fluorescence intensity changes have been observed in the pH range from 3 to 10 and in a wide variety of polar and hydrophobic solvents with vastly different dielectric constants. The high extinction and fluorescence quantum yield of these probes make them ideal fluorescent labeling reagents for proteins, antibodies, nucleic acids, and cellular organelles. The pH and hydrophobicity-dependent fluorescence changes can be utilized as optical pH and/or hydrophobicity indicators for mapping environmental difference in various cellular components in a single cell. Since all nine probes absorb in the UV, but emit at different wavelengths in the visible, these two groups of compounds offer an advantage of utilizing a single monochromatic light source (e.g., a nitrogen laser) to achieve multi-wavelength detection for flow cytometry application. As a first step to explore potential application in

  15. Miniaturised optical fiber pH sensor for gastro-esophageal applications

    Science.gov (United States)

    Baldini, F.; Chiavaioli, F.; Cosi, F.; Giannetti, A.; Tombelli, S.; Trono, C.

    2013-05-01

    Monitoring pH for long periods, usually 24 h, in the stomach and in the esophagus may be essential in the diagnosis of gastro-esophageal diseases. The clinical range of interest is quite extended, between 1 to 8 pH units. Methyl red, after its covalent immobilization on controlled pore glass (CPG), is characterized by a working range which fits well with the clinical one. A novel probe, suitable for gastro-esophageal applications, was designed in order to optimize the performances of the colored CPG. This leads to a very simple probe configuration characterized by a very fast response.

  16. Synthesis of a Cu2+-Selective Probe Derived from Rhodamine and Its Application in Cell Imaging

    Directory of Open Access Journals (Sweden)

    Chunwei Yu

    2014-11-01

    Full Text Available A new fluorescent probe P based on rhodamine for Cu2+ was synthesized and characterized. The new probe P showed high selectivity to Cu2+ over other tested metal ions. With optimal conditions, the proposed probe P worked in a wide linear range of 1.0 × 10−6–1.0 × 10−5 M with a detection limit of 3.3 × 10−7 M Cu2+ in ethanol-water solution (9:1, v:v, 20 mM HEPES, pH 7.0. Furthermore, it has been used for imaging of Cu2+ in living cells with satisfying results.

  17. pHlash: a new genetically encoded and ratiometric luminescence sensor of intracellular pH.

    Science.gov (United States)

    Zhang, Yunfei; Xie, Qiguang; Robertson, J Brian; Johnson, Carl Hirschie

    2012-01-01

    We report the development of a genetically encodable and ratiometic pH probe named "pHlash" that utilizes Bioluminescence Resonance Energy Transfer (BRET) rather than fluorescence excitation. The pHlash sensor-composed of a donor luciferase that is genetically fused to a Venus fluorophore-exhibits pH dependence of its spectral emission in vitro. When expressed in either yeast or mammalian cells, pHlash reports basal pH and cytosolic acidification in vivo. Its spectral ratio response is H(+) specific; neither Ca(++), Mg(++), Na(+), nor K(+) changes the spectral form of its luminescence emission. Moreover, it can be used to image pH in single cells. This is the first BRET-based sensor of H(+) ions, and it should allow the approximation of pH in cytosolic and organellar compartments in applications where current pH probes are inadequate.

  18. pHlash: a new genetically encoded and ratiometric luminescence sensor of intracellular pH.

    Directory of Open Access Journals (Sweden)

    Yunfei Zhang

    Full Text Available We report the development of a genetically encodable and ratiometic pH probe named "pHlash" that utilizes Bioluminescence Resonance Energy Transfer (BRET rather than fluorescence excitation. The pHlash sensor-composed of a donor luciferase that is genetically fused to a Venus fluorophore-exhibits pH dependence of its spectral emission in vitro. When expressed in either yeast or mammalian cells, pHlash reports basal pH and cytosolic acidification in vivo. Its spectral ratio response is H(+ specific; neither Ca(++, Mg(++, Na(+, nor K(+ changes the spectral form of its luminescence emission. Moreover, it can be used to image pH in single cells. This is the first BRET-based sensor of H(+ ions, and it should allow the approximation of pH in cytosolic and organellar compartments in applications where current pH probes are inadequate.

  19. Microscopic monitoring of extracellular pH in dental biofilms

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Garcia, Javier; Greve, Matilde

    pH in dental biofilm is a key virulence factor for the development of caries lesions. The complex three-dimensional architecture of dental biofilms leads to steep gradients of nutrients and metabolites, including organic acids, across the biofilm. For decades, measuring pH in dental biofilm has...... been limited to monitoring bulk pH with electrodes. Although pH microelectrodes with a better spatial resolution have been developed, they do not permit to monitor horizontal pH gradients in real-time. Quantitative fluorescent microscopic techniques, such as fluorescence lifetime imaging or pH...... ratiometry, can be employed to map the pH landscape in dental biofilm with more detail. However, when pH sensitive fluorescent probes are used to visualize pH in biofilms, it is crucial to differentiate between extracellular and intracellular pH. Intracellular microbial pH and pH in the extracellular matrix...

  20. High sensitivity pH sensing on the BEOL of industrial FDSOI transistors

    Science.gov (United States)

    Rahhal, Lama; Ayele, Getenet Tesega; Monfray, Stéphane; Cloarec, Jean-Pierre; Fornacciari, Benjamin; Pardoux, Eric; Chevalier, Celine; Ecoffey, Serge; Drouin, Dominique; Morin, Pierre; Garnier, Philippe; Boeuf, Frederic; Souifi, Abdelkader

    2017-08-01

    In this work we demonstrate the use of Fully Depleted Silicon On Insulator (FDSOI) transistors as pH sensors with a 23 nm silicon nitride sensing layer built in the Back-End-Of-Line (BEOL). The back end process to deposit the sensing layer and fabricate the electrical structures needed for testing is detailed. A series of tests employing different pH buffer solutions has been performed on transistors of different geometries, controlled via the back gate. The main findings show a shift of the drain current (ID) as a function of the back gate voltage (VB) when different pH buffer solutions are probed in the range of pH 6 to pH 8. This shift is observed at VB voltages swept from 0 V to 3 V, demonstrating the sensor operation at low voltage. A high sensitivity of up to 250 mV/pH unit (more than 4-fold larger than Nernstian response) is observed on FDSOI MOS transistors of 0.06 μm gate length and 0.08 μm gate width. She is currently working as a Postdoctoral researcher at Institut des nanotechnologies de Lyon in collaboration with STMicroelectronics and Université de Sherbrook (Canada) working on ;Integration of ultra-low-power gas and pH sensors with advanced technologies;. Her research interest includes selection, machining, optimisation and electrical characterisation of the sensitive layer for a low power consumption gas sensor based on advanced MOS transistors.

  1. PhD on Track – designing learning for PhD students

    Directory of Open Access Journals (Sweden)

    Gunhild Austrheim

    2013-12-01

    Full Text Available Three years ago we started the project "Information Management for Knowledge Creation". The project was initiated to create online information literacy modules for PhD students. The result of our endeavours, PhD on Track, will be launched in May 2013. The initial stage of the project was mapping out the information behaviour of PhD students, as well as what services they require from the library through a literature review and a focus group study. The findings of these inquiries formed the knowledge base from which we developed our information literacy modules. Our paper will focus on the interaction between content production and user testing when creating PhD on Track. Methods: User testing has been employed throughout the production stage. We have tested navigation and organisation of the web site, content and usability. The project team have conducted expert testing. Analysis: The results from our user testing have played an important part in decisions concerning content production. Our working hypothesis was that the PhD students would want an encyclopaedic website, a place to quickly find answers. However, the user tests revealed that PhD students understood and expected the website to be learning modules. Conclusions: The PhD students in the tests agreed that a site such as this would be useful, especially to new PhD students. They also liked the design, but had some qualms with the level of information. They preferred shorter text, but with more depth. The students would likewise have preferred more practical examples, more illustrations and more discipline specific information. The current content of PhD on Track reflects the feedback from the user testing. We have retained initial ideas such as one section for reviewing and discovering research literature and one section for publishing PhD research work. In addition, we have included more practical examples to indicate efficient workflows or relevant actions in context. Illustrations

  2. pH-Induced Modulation of One- and Two-Photon Absorption Properties in a Naphthalene-Based Molecular Probe.

    Science.gov (United States)

    Murugan, N Arul; Kongsted, Jacob; Ågren, Hans

    2013-08-13

    Presently, there is a great demand for small probe molecules that can be used for two-photon excitation microscopy (TPM)-based monitoring of intracellular and intraorganelle activity and pH. The candidate molecules should ideally possess a large two-photon absorption cross section with optical properties sensitive to pH changes. In the present work, we investigate the potential of a methoxy napthalene (MONAP) derivative for its suitability to serve as a pH sensor using TPM. Using an integrated approach rooted in hybrid quantum mechanics/molecular mechanics, the structures, dynamics, and the one- and two-photon properties of the probe in dimethylformamide solvent are studied. It is found that the protonated form is responsible for the optical property of MONAP at moderately low pH, for which the calculated pH-induced red shift is in good agreement with experiments. A 2-fold increase in the two-photon absorption cross section in the IR region of the spectrum is predicted for the moderately low pH form of the probe, suggesting that this can be a potential probe for pH monitoring of living cells. We also propose some design principles aimed at obtaining control of the absorption spectral range of the probe by structural tuning. Our work indicates that the integrated approach employed is capable of capturing the pH-induced changes in structure and optical properties of organic molecular probes and that such in silico tools can be used to draw structure-property relationships to design novel molecular probes suitable for a specific application.

  3. Rapid antibiotic susceptibility testing in a microfluidic pH sensor.

    Science.gov (United States)

    Tang, Yanyan; Zhen, Li; Liu, Jingqing; Wu, Jianmin

    2013-03-05

    For appropriate selection of antibiotics in the treatment of pathogen infection, rapid antibiotic susceptibility testing (AST) is urgently needed in clinical practice. This study reports the utilization of a microfluidic pH sensor for monitoring bacterial growth rate in culture media spiked with different kinds of antibiotics. The microfluidic pH sensor was fabricated by integration of pH-sensitive chitosan hydrogel with poly(dimethylsiloxane) (PDMS) microfluidic channels. For facilitating the reflectometric interference spectroscopic measurements, the chitosan hydrogel was coated on an electrochemically etched porous silicon chip, which was used as the substrate of the microfluidic channel. Real-time observation of the pH change in the microchannel can be realized by Fourier transform reflectometric interference spectroscopy (FT-RIFS), in which the effective optical thickness (EOT) was selected as the optical signal for indicating the reversible swelling process of chitosan hydrogel stimulated by pH change. With this microfluidic pH sensor, we demonstrate that confinement of bacterial cells in a nanoliter size channel allows rapid accumulation of metabolic products and eliminates the need for long-time preincubation, thus reducing the whole detection time. On the basis of this technology, the whole bacterial growth curve can be obtained in less than 2 h, and consequently rapid AST can be realized. Compared with conventional methods, the AST data acquired from the bacterial growth curve can provide more detailed information for studying the antimicrobial behavior of antibiotics during different stages. Furthermore, the new technology also provides a convenient method for rapid minimal inhibition concentration (MIC) determination of individual antibiotics or the combinations of antibiotics against human pathogens that will find application in clinical and point-of-care medicine.

  4. Dental plaque pH and ureolytic activity in children and adults of a low caries population.

    Science.gov (United States)

    Appelgren, Linnea; Dahlén, Anna; Eriksson, Cecilia; Suksuart, Narong; Dahlén, Gunnar

    2014-04-01

    The aim of this study was to evaluate the plaque pH level and ureolytic activity among children and adults of Karen Hill tribes. Thirty-four children aged 6-10 years and 46 adults aged 20-38 years were interviewed regarding oral hygiene practices, sucrose intake and betel chewing. Caries experience (DMFT and DT), calculus, bleeding on probing (BoP) and Plaque index (PlI) were registered. Ureolytic activity in supragingival plaque was tested at two interproximal sites (11/12 and 41/42) with the rapid urease test (RUT). Registration of plaque pH was performed at two interproximal sites (15/16 and 31/41) before, during and 30 min after rinsing with an urea solution (0.25%). Four interproximal plaque samples (one from each quadrant) per individual were collected to test the bacterial composition using the checkerboard technique. Children and adults had similarly low DMFT and DT values. Children had a higher baseline pH and a higher ureolytic activity in the maxilla (p plaque pH is related to the ureolytic activity, which explains the low acidogenic plaque microflora and the low caries levels in the Karen population.

  5. Measurement of pH micro-heterogeneity in natural cheese matrices by fluorescence lifetime imaging

    Directory of Open Access Journals (Sweden)

    Zuzana eBurdikova

    2015-03-01

    Full Text Available Cheese, a product of microbial fermentation may be defined as a protein matrix entrapping fat, moisture, minerals and solutes as well as dispersed bacterial colonies. The growth and physiology of bacterial cells in these colonies may be influenced by the microenvironment around the colony, or alternatively the cells within the colony may modify the microenvironment (e.g. pH, redox potential due to their metabolic activity. While cheese pH may be measured at macro level there remains a significant knowledge gap relating to the degree of micro-heterogeneity of pH within the cheese matrix and its relationship with microbial, enzymatic and physiochemical parameters and ultimately with cheese quality, consistency and ripening patterns. The pH of cheese samples was monitored both at macroscopic scale and at microscopic scale, using a non-destructive microscopic technique employing C-SNARF-4 and Oregon Green 488 fluorescent probes. The objectives of this work were to evaluate the suitability of these dyes for microscale pH measurements in natural cheese matrices and to enhance the sensitivity and extend the useful pH range of these probes using fluorescence lifetime imaging (FLIM. In particular, fluorescence lifetime of Oregon Green 488 proved to be sensitive probe to map pH micro heterogeneity within cheese matrices. Good agreement was observed between macroscopic scale pH measurement by FLIM and by traditional pH methods, but in addition considerable localized microheterogeneity in pH was evident within the curd matrix with pH range between 4.0 and 5.5. This technique provides significant potential to further investigate the relationship between cheese matrix physico-chemistry and bacterial metabolism during cheese manufacture and ripening.

  6. Measurement of pH micro-heterogeneity in natural cheese matrices by fluorescence lifetime imaging.

    Science.gov (United States)

    Burdikova, Zuzana; Svindrych, Zdenek; Pala, Jan; Hickey, Cian D; Wilkinson, Martin G; Panek, Jiri; Auty, Mark A E; Periasamy, Ammasi; Sheehan, Jeremiah J

    2015-01-01

    Cheese, a product of microbial fermentation may be defined as a protein matrix entrapping fat, moisture, minerals and solutes as well as dispersed bacterial colonies. The growth and physiology of bacterial cells in these colonies may be influenced by the microenvironment around the colony, or alternatively the cells within the colony may modify the microenvironment (e.g., pH, redox potential) due to their metabolic activity. While cheese pH may be measured at macro level there remains a significant knowledge gap relating to the degree of micro-heterogeneity of pH within the cheese matrix and its relationship with microbial, enzymatic and physiochemical parameters and ultimately with cheese quality, consistency and ripening patterns. The pH of cheese samples was monitored both at macroscopic scale and at microscopic scale, using a non-destructive microscopic technique employing C-SNARF-4 and Oregon Green 488 fluorescent probes. The objectives of this work were to evaluate the suitability of these dyes for microscale pH measurements in natural cheese matrices and to enhance the sensitivity and extend the useful pH range of these probes using fluorescence lifetime imaging (FLIM). In particular, fluorescence lifetime of Oregon Green 488 proved to be sensitive probe to map pH micro heterogeneity within cheese matrices. Good agreement was observed between macroscopic scale pH measurement by FLIM and by traditional pH methods, but in addition considerable localized microheterogeneity in pH was evident within the curd matrix with pH range between 4.0 and 5.5. This technique provides significant potential to further investigate the relationship between cheese matrix physico-chemistry and bacterial metabolism during cheese manufacture and ripening.

  7. Investigating the use of endogenous quinoid moieties on carbon fibre as means of developing micro pH sensors

    International Nuclear Information System (INIS)

    Anderson, Ashleigh; Phair, Jolene; Benson, John; Meenan, Brian; Davis, James

    2014-01-01

    The redox profile obtained from electrochemically oxidised carbon fibre was exploited as a foundation from which to design a reusable pH probe. X-ray photoelectron spectroscopy of the surface after anodisation revealed an increase in the population of endogenous quinone moieties. Square wave voltammograms recorded in various buffer solutions (pH 3–9) yielded a distinct and unambiguous oxidation process through which to ascribe the peak potential — with the latter found to shift in a sub-Nernstian (− 0.052 V/pH) manner. The design of a discrete 2-electrode reusable probe which provides a rapid assessment of pH is described and a preliminary characterisation of the electrochemical performance is critically assessed. - Graphical abstract: The redox profile obtained from electrochemically oxidised carbon fibre was exploited as a foundation from which to design a reusable pH probe. X-ray photoelectron spectroscopy of the surface after anodisation revealed an increase in the population endogenous quinone moieties. Square wave voltammograms recorded in various buffer solutions (pH 3–9) yielded a distinct and unambiguous oxidation process through which to ascribe the peak potential — with the latter found to shift in a sub-Nernstian (− 0.052 V/pH) manner. The design of a discrete 2-electrode reusable probe which provides a rapid assessment of pH is described and a preliminary characterisation of the electrochemical performance is critically assessed. - Highlights: • In situ creation of pH sensitive quinone groups on carbon fibre • Versatile and accessible approach to manufacturing disposable pH sensors • Miniature probe design enables monitoring pH in small volumes. • Detailed surface characterisation of electrochemically modified carbon fibre

  8. Investigating the use of endogenous quinoid moieties on carbon fibre as means of developing micro pH sensors

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Ashleigh; Phair, Jolene; Benson, John; Meenan, Brian; Davis, James, E-mail: james.davis@ulster.ac.uk

    2014-10-01

    The redox profile obtained from electrochemically oxidised carbon fibre was exploited as a foundation from which to design a reusable pH probe. X-ray photoelectron spectroscopy of the surface after anodisation revealed an increase in the population of endogenous quinone moieties. Square wave voltammograms recorded in various buffer solutions (pH 3–9) yielded a distinct and unambiguous oxidation process through which to ascribe the peak potential — with the latter found to shift in a sub-Nernstian (− 0.052 V/pH) manner. The design of a discrete 2-electrode reusable probe which provides a rapid assessment of pH is described and a preliminary characterisation of the electrochemical performance is critically assessed. - Graphical abstract: The redox profile obtained from electrochemically oxidised carbon fibre was exploited as a foundation from which to design a reusable pH probe. X-ray photoelectron spectroscopy of the surface after anodisation revealed an increase in the population endogenous quinone moieties. Square wave voltammograms recorded in various buffer solutions (pH 3–9) yielded a distinct and unambiguous oxidation process through which to ascribe the peak potential — with the latter found to shift in a sub-Nernstian (− 0.052 V/pH) manner. The design of a discrete 2-electrode reusable probe which provides a rapid assessment of pH is described and a preliminary characterisation of the electrochemical performance is critically assessed. - Highlights: • In situ creation of pH sensitive quinone groups on carbon fibre • Versatile and accessible approach to manufacturing disposable pH sensors • Miniature probe design enables monitoring pH in small volumes. • Detailed surface characterisation of electrochemically modified carbon fibre.

  9. pH homeostasis in Escherichia coli: measurement by 31P nuclear magnetic resonance of methylphosphonate and phosphate

    International Nuclear Information System (INIS)

    Slonczewski, J.L.; Rosen, B.P.; Alger, J.R.; Macnab, R.M.

    1981-01-01

    The intracellular pH of Escherichia coli cells, respiring on endogenous energy sources, was monitored continuously by 31 P NMR over an extracellular pH range between 5.5 and 9. pH homeostasis was found to be good over the entire range, with the data conforming to the simple relationship intracellular pH = 7.6 + 0.1(external pH - 7.6) so that the extreme values observed for intracellular pH were 7.4 and 7.8 external pH 5.5 and 9, respectively. As well as inorganic phosphate, we employed the pH-sensitive NMR probe methylphosphonate, which was taken up by glycerol-grown cells and was nontoxic; its pK/sub a/ of 7.65 made it an ideal probe for measurement of cytoplasmic pH and alkaline external pH

  10. Testing the Solar Probe Cup, an Instrument Designed to Touch the Sun

    Science.gov (United States)

    Whittlesey, Phyllis L.; Case, Anthony W.; Kasper, Justin Christophe; Wright, Kenneth H., Jr.; Alterman, Ben; Cirtain, Jonathan W.; Bookbinder, Jay; Korreck, Kelly E.; Stevens, Michael Louis

    2014-01-01

    Solar Probe Plus will be the first, fastest, and closest mission to the sun, providing the first direct sampling of the sub-Alfvenic corona. The Solar Probe Cup (SPC) is a unique re-imagining of the traditional Faraday Cup design and materials for immersion in this high temperature environment. Sending an instrument of this type into a never-seen particle environment requires extensive characterization prior to launch to establish sufficient measurement accuracy and instrument response. To reach this end, a slew of tests for allowing SPC to see ranges of appropriate ions and electrons, as well as a facility that reproduces solar photon spectra and fluxes for this mission. Having already tested the SPC at flight like temperatures with no significant modification of the noise floor, we recently completed a round of particle testing to see if the deviations in Faraday Cup design fundamentally change the operation of the instrument. Results and implications from these tests will be presented, as well as performance comparisons to cousin instruments such as those on the WIND spacecraft.

  11. A luminescence-based probe for sensitive detection of hydrogen peroxide in seconds

    International Nuclear Information System (INIS)

    Zscharnack, Kristin; Kreisig, Thomas; Prasse, Agneta A.; Zuchner, Thole

    2014-01-01

    Highlights: • We describe a novel probe for the sensitive detection of H 2 O 2 . • H 2 O 2 quenches the luminescence of a complex consisting of phthalic acid and terbium ions. • A stable fluorescence signal is generated immediately after mixing probe and sample. • The PATb probe detects H 2 O 2 over four orders of magnitude. - Abstract: Here, we present a fast and simple hydrogen peroxide assay that is based on time-resolved fluorescence. The emission intensity of a complex consisting of terbium ions (Tb 3+ ) and phthalic acid (PA) in HEPES buffer is quenched in the presence of H 2 O 2 and this quenching is concentration-dependent. The novel PATb assay detects hydrogen peroxide at a pH range from 7.5 to 8.5 and with a detection limit of 150 nmol L −1 at pH 8.5. The total assay time is less than 1 min. The linear range of the assay can be adapted by a pH adjustment of the aqueous buffer and covers a concentration range from 310 nmol L −1 to 2.56 mmol L −1 in total which encompasses four orders of magnitude. The assay is compatible with high concentrations of all 47 tested inorganic and organic compounds. The PATb assay was applied to quantify H 2 O 2 in polluted river water samples. In conclusion, this fast and easy-to-use assay detects H 2 O 2 with high sensitivity and precision

  12. Skin pH, Atopic Dermatitis, and Filaggrin Mutations

    DEFF Research Database (Denmark)

    Bandier, Josefine; Johansen, Jeanne Duus; Petersen, Lars Jelstrup

    2014-01-01

    mutations may influence skin pH. OBJECTIVE: We aimed to determine the epidermal pH in different groups stratified by filaggrin mutations and atopic dermatitis. Further, we investigated the changes in pH according to severity of mutational status among patients with dermatitis, irrespective of skin condition....... METHODS: pH was measured with a multiprobe system pH probe (PH 905), and the study population was composed of 67 individuals, who had all been genotyped for 3 filaggrin mutations (R501X, 2282del4, R2447X). RESULTS: We found no clear pattern in relation to filaggrin mutation carrier status. Individuals...... with wild-type filaggrin displayed both the most acidic and most alkaline values independent of concomitant skin disease; however, no statistical differences between the groups were found. CONCLUSIONS: The lack of significant diversity in skin pH in relation to filaggrin mutation carrier status suggests...

  13. Precise detection of pH inside large unilamellar vesicles using membrane-impermeable dendritic porphyrin-based nanoprobes.

    Science.gov (United States)

    Leiding, Thom; Górecki, Kamil; Kjellman, Tomas; Vinogradov, Sergei A; Hägerhäll, Cecilia; Arsköld, Sindra Peterson

    2009-05-15

    Accurate real-time measurements of proton concentration gradients are pivotal to mechanistic studies of proton translocation by membrane-bound enzymes. Here we report a detailed characterization of the pH-sensitive fluorescent nanoprobe Glu(3), which is well suited for pH measurements in microcompartmentalized biological systems. The probe is a polyglutamic porphyrin dendrimer in which multiple carboxylate termini ensure its high water solubility and prevent its diffusion across phospholipid membranes. The probe's pK is in the physiological pH range, and its protonation can be followed ratiometrically by absorbance or fluorescence in the ultraviolet-visible spectral region. The usefulness of the probe was enhanced by using a semiautomatic titration system coupled to a charge-coupled device (CCD) spectrometer, enabling fast and accurate titrations and full spectral coverage of the system at millisecond time resolution. The probe's pK was measured in bulk solutions as well as inside large unilamellar vesicles in the presence of physiologically relevant ions. Glu(3) was found to be completely membrane impermeable, and its distinct spectroscopic features permit pH measurements inside closed membrane vesicles, enabling quantitative mechanistic studies of membrane-spanning proteins. Performance of the probe was demonstrated by monitoring the rate of proton leakage through the phospholipid bilayer in large vesicles with and without the uncoupler gramicidin present. Overall, as a probe for biological proton translocation measurements, Glu(3) was found to be superior to the commercially available pH indicators.

  14. Influence of pH on organic acid production by Clostridium sporogenes in test tube and fermentor cultures.

    Science.gov (United States)

    Montville, T J; Parris, N; Conway, L K

    1985-01-01

    The influence of pH on the growth parameters of and the organic acids produced by Clostridium sporogenes 3121 cultured in test tubes and fermentors at 35 degrees C was examined. Specific growth rates in the fermentor maintained at a constant pH ranged from 0.20 h-1 at pH 5.00 to 0.86 h-1 at pH 6.50. Acetic acid was the primary organic acid in supernatants of 24-h cultures; total organic acid levels were 2.0 to 22.0 mumol/ml. Supernatants from pH 5.00 and 5.50 cultures had total organic acid levels less than one-third of those found at pH 6.00 to 7.00. The specific growth rates of the test tube cultures ranged from 0.51 h-1 at pH 5.00 to 0.95 h-1 at pH 6.50. The pH of the medium did not affect the average total organic acid content (51.5 mumol/ml) but did affect the distribution of the organic acids, which included formic, acetic, propionic, butyric, 3-(p-hydroxyphenyl)propionic, and 3-phenylpropionic acids. Butyric acid levels were lower, but formic and propionic acid levels were higher, at pH 5.00 than at other pHs. PMID:4004207

  15. Nanoparticle assembled microcapsules for application as pH and ammonia sensor

    International Nuclear Information System (INIS)

    Amali, Arlin Jose; Awwad, Nour H.; Rana, Rohit Kumar; Patra, Digambara

    2011-01-01

    Graphical abstract: HPTS encapsulated nanoparticle assembled microcapsule is exploited as dual excitations ratiometic pH sensor. This nanoparticle assembled microcapsule based fluorescence sensor can determine ammonia and offers a robust, simple and fast sensing material. Highlights: ► A novel HPTS encapsulated nanoparticle assembled microcapsule is developed. ► Its dual excitation facilitates a ratiometic pH sensor. ► It is successfully applied for the determination of ammonia. ► It provides a robust, simple and fast sensing material. - Abstract: The encapsulation of molecular probes in a suitable nanostructured matrix can be exploited to alter their optical properties and robustness for fabricating efficient chemical sensors. Despite high sensitivity, simplicity, selectivity and cost effectiveness, the photo-destruction and photo-bleaching are the serious concerns while utilizing molecular probes. Herein we demonstrate that hydroxy pyrene trisulfonate (HPTS), a pH sensitive molecular probe, when encapsulated in a microcapsule structure prepared via the assembly of silica nanoparticles mediated by poly-L-lysine and trisodium citrate, provides a robust sensing material for pH sensing under the physiological conditions. The temporal evolution under continuous irradiation indicates that the fluorophore inside the silica microcapsule is extraordinarily photostable. The fluorescence intensity alternation at dual excitation facilitates for a ratiometic sensing of the pH, however, the fluorescence lifetime is insensitive to hydrogen ion concentration. The sensing scheme is found to be robust, fast and simple for the measurement of pH in the range 5.8–8.0, and can be successfully applied for the determination of ammonia in the concentration range 0–1.2 mM, which is important for aquatic life and the environment.

  16. Establishment of a novel immunoassay system for rapid detection of 2,4-dichlorophenoxyacetic acid residues based on magnetic-fluorescent probes

    Directory of Open Access Journals (Sweden)

    WANG Yuanfeng

    2014-12-01

    Full Text Available A novel immunoassay system based on magnetic-fluorescent probes was established to detect 2.4-dichlorophenoxyacetic acid (2,4-D residue in liquid system in food and agricultural products.The composites of anti-2,4-D antibody bound to Fe3O4@SiO2-NH2 was employed as the solid phase as well as magnetic probe.The composites composed of 2,4-D-OVA labeled with CdTe@SiO2-NH2 as the fluorescent probe was used to produce fluorescent signal.2,4-D and its fluorescent probe competed binding the antibody on the surface of the magnetic probe.The optimization of 2,4-D-OVA dosage,coupling PH and reaction time in preparing the fluorescent probe were investigated.It showed that in the synthesis of fluorescent probe 8.2 was the optimal pH,70 min was the optimal coupling time,500 μL amount of 2,4-D-OVA.The standard curve was obtained with the concentration of 2,4-D and the maximum fluorescence intensity.The detection limit of the assay was gotten and it was 3.55×10-8.One reaction step and one washing step were needed.The assay significantly shortened the testing time and amplified the detection signal compared with classic ELISA.

  17. A Simple Method for Decreasing the Liquid Junction Potential in a Flow-through-Type Differential pH Sensor Probe Consisting of pH-FETs by Exerting Spatiotemporal Control of the Liquid Junction

    Science.gov (United States)

    Yamada, Akira; Mohri, Satoshi; Nakamura, Michihiro; Naruse, Keiji

    2015-01-01

    The liquid junction potential (LJP), the phenomenon that occurs when two electrolyte solutions of different composition come into contact, prevents accurate measurements in potentiometry. The effect of the LJP is usually remarkable in measurements of diluted solutions with low buffering capacities or low ion concentrations. Our group has constructed a simple method to eliminate the LJP by exerting spatiotemporal control of a liquid junction (LJ) formed between two solutions, a sample solution and a baseline solution (BLS), in a flow-through-type differential pH sensor probe. The method was contrived based on microfluidics. The sensor probe is a differential measurement system composed of two ion-sensitive field-effect transistors (ISFETs) and one Ag/AgCl electrode. With our new method, the border region of the sample solution and BLS is vibrated in order to mix solutions and suppress the overshoot after the sample solution is suctioned into the sensor probe. Compared to the conventional method without vibration, our method shortened the settling time from over two min to 15 s and reduced the measurement error by 86% to within 0.060 pH. This new method will be useful for improving the response characteristics and decreasing the measurement error of many apparatuses that use LJs. PMID:25835300

  18. A small molecular pH-dependent fluorescent probe for cancer cell imaging in living cell.

    Science.gov (United States)

    Ma, Junbao; Li, Wenqi; Li, Juanjuan; Shi, Rongguang; Yin, Gui; Wang, Ruiyong

    2018-05-15

    A novel pH-dependent two-photon fluorescent molecular probe ABMP has been prepared based on the fluorophore of 2, 4, 6-trisubstituted pyridine. The probe has an absorption wavelength at 354 nm and corresponding emission wavelength at 475 nm with the working pH range from 2.20 to 7.00, especially owning a good liner response from pH = 2.40 to pH = 4.00. ABMP also has excellent reversibility, photostability and selectivity which promotes its ability in analytical application. The probe can be excited with a two-photon fluorescence microscopy and the fluorescence cell imaging indicated that the probe can distinguish Hela cancer cells out of normal cells with a two-photon fluorescence microscopy which suggested its potential application in tumor cell detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Intracellular pH in rat pancreatic ducts

    DEFF Research Database (Denmark)

    Novak, I; Hug, M; Greger, R

    1997-01-01

    In order to study the mechanism of H+ and HCO3- transport in a HCO3- secreting epithelium, pancreatic ducts, we have measured the intracellular pH (pHi) in this tissue using the pH sensitive probe BCECF. We found that exposures of ducts to solutions containing acetate/acetic acid or NH4+/NH3...... buffers (20 mmol/l) led to pHi changes in accordance with entry of lipid-soluble forms of the buffers, followed by back-regulation of pHi by duct cells. In another type of experiment, changes in extracellular pH of solutions containing HEPES or HCO3-/CO2 buffers led to significant changes in pHi that did....... Under some conditions, these exchangers can be invoked to regulate cell pH....

  20. Multifunctional PHPMA-Derived Polymer for Ratiometric pH Sensing, Fluorescence Imaging, and Magnetic Resonance Imaging.

    Science.gov (United States)

    Su, Fengyu; Agarwal, Shubhangi; Pan, Tingting; Qiao, Yuan; Zhang, Liqiang; Shi, Zhengwei; Kong, Xiangxing; Day, Kevin; Chen, Meiwan; Meldrum, Deirdre; Kodibagkar, Vikram D; Tian, Yanqing

    2018-01-17

    In this paper, we report synthesis and characterization of a novel multimodality (MRI/fluorescence) probe for pH sensing and imaging. A multifunctional polymer was derived from poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) and integrated with a naphthalimide-based-ratiometric fluorescence probe and a gadolinium-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid complex (Gd-DOTA complex). The polymer was characterized using UV-vis absorption spectrophotometry, fluorescence spectrofluorophotometry, magnetic resonance imaging (MRI), and confocal microscopy for optical and MRI-based pH sensing and cellular imaging. In vitro labeling of macrophage J774 and esophageal CP-A cell lines shows the polymer's ability to be internalized in the cells. The transverse relaxation time (T 2 ) of the polymer was observed to be pH-dependent, whereas the spin-lattice relaxation time (T 1 ) was not. The pH probe in the polymer shows a strong fluorescence-based ratiometric pH response with emission window changes, exhibiting blue emission under acidic conditions and green emission under basic conditions, respectively. This study provides new materials with multimodalities for pH sensing and imaging.

  1. A Dual Sensor for pH and Hydrogen Peroxide Using Polymer-Coated Optical Fibre Tips.

    Science.gov (United States)

    Purdey, Malcolm S; Thompson, Jeremy G; Monro, Tanya M; Abell, Andrew D; Schartner, Erik P

    2015-12-17

    This paper demonstrates the first single optical fibre tip probe for concurrent detection of both hydrogen peroxide (H₂O₂) concentration and pH of a solution. The sensor is constructed by embedding two fluorophores: carboxyperoxyfluor-1 (CPF1) and seminaphtharhodafluor-2 (SNARF2) within a polymer matrix located on the tip of the optical fibre. The functionalised fibre probe reproducibly measures pH, and is able to accurately detect H₂O₂ over a biologically relevant concentration range. This sensor offers potential for non-invasive detection of pH and H₂O₂ in biological environments using a single optical fibre.

  2. Experience With Routine Vaginal pH Testing in a Family Practice Setting

    Directory of Open Access Journals (Sweden)

    Adriana J. Pavletic

    2004-01-01

    Full Text Available Background: Despite recommendations by Centers for Disease Control and the American College of Obstetricians and Gynecologists, pH testing is infrequently performed during the evaluation of vaginitis. Consequently, little information exists on its use in a primary care setting.

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

    Science.gov (United States)

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

    2016-04-01

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

  4. Dynamic pressure probe response tests for robust measurements in periodic flows close to probe resonating frequency

    Science.gov (United States)

    Ceyhun Şahin, Fatma; Schiffmann, Jürg

    2018-02-01

    A single-hole probe was designed to measure steady and periodic flows with high fluctuation amplitudes and with minimal flow intrusion. Because of its high aspect ratio, estimations showed that the probe resonates at a frequency two orders of magnitude lower than the fast response sensor cut-off frequencies. The high fluctuation amplitudes cause a non-linear behavior of the probe and available models are neither adequate for a quantitative estimation of the resonating frequencies nor for predicting the system damping. Instead, a non-linear data correction procedure based on individual transfer functions defined for each harmonic contribution is introduced for pneumatic probes that allows to extend their operating range beyond the resonating frequencies and linear dynamics. This data correction procedure was assessed on a miniature single-hole probe of 0.35 mm inner diameter which was designed to measure flow speed and direction. For the reliable use of such a probe in periodic flows, its frequency response was reproduced with a siren disk, which allows exciting the probe up to 10 kHz with peak-to-peak amplitudes ranging between 20%-170% of the absolute mean pressure. The effect of the probe interior design on the phase lag and amplitude distortion in periodic flow measurements was investigated on probes with similar inner diameters and different lengths or similar aspect ratios (L/D) and different total interior volumes. The results suggest that while the tube length consistently sets the resonance frequency, the internal total volume affects the non-linear dynamic response in terms of varying gain functions. A detailed analysis of the introduced calibration methodology shows that the goodness of the reconstructed data compared to the reference data is above 75% for fundamental frequencies up to twice the probe resonance frequency. The results clearly suggest that the introduced procedure is adequate to capture non-linear pneumatic probe dynamics and to

  5. A new thermal conductivity probe for high temperature tests for the characterization of molten salts

    Science.gov (United States)

    Bovesecchi, G.; Coppa, P.; Pistacchio, S.

    2018-05-01

    A new thermal conductivity probe for high temperature (HT-TCP) has been built and tested. Its design and construction procedure are adapted from the ambient temperature thermal conductivity probe (AT-TCP) due to good performance of the latter device. The construction procedure and the preliminary tests are accurately described. The probe contains a Pt wire as a heater and a type K thermocouple (TC) as a temperature sensor, and its size is so small (0.6 mm in diameter and 60 mm in length) as to guarantee a length to diameter ratio of about 100. Calibration tests with glycerol for temperatures between 0 °C and 60 °C have shown good agreement with literature data, within 3%. Preliminary tests were also carried on a ternary molten salt for Concentrated Solar Power (CSP) (18% in mass of NaNO3, 52% KNO3, and 30% LiNO3) at 120 °C and 150 °C. Obtained results are within λ range of the Hitec® salt (53% KNO3, 7% NaNO3, 40% NaNO2). Unfortunately, at the higher temperature tested (200 °C), the viscosity of the salt highly decreases, and free convection starts, making the measurements unreliable.

  6. Dark energy two decades after: observables, probes, consistency tests.

    Science.gov (United States)

    Huterer, Dragan; Shafer, Daniel L

    2018-01-01

    The discovery of the accelerating universe in the late 1990s was a watershed moment in modern cosmology, as it indicated the presence of a fundamentally new, dominant contribution to the energy budget of the universe. Evidence for dark energy, the new component that causes the acceleration, has since become extremely strong, owing to an impressive variety of increasingly precise measurements of the expansion history and the growth of structure in the universe. Still, one of the central challenges of modern cosmology is to shed light on the physical mechanism behind the accelerating universe. In this review, we briefly summarize the developments that led to the discovery of dark energy. Next, we discuss the parametric descriptions of dark energy and the cosmological tests that allow us to better understand its nature. We then review the cosmological probes of dark energy. For each probe, we briefly discuss the physics behind it and its prospects for measuring dark energy properties. We end with a summary of the current status of dark energy research.

  7. A Dual Sensor for pH and Hydrogen Peroxide Using Polymer-Coated Optical Fibre Tips

    Directory of Open Access Journals (Sweden)

    Malcolm S. Purdey

    2015-12-01

    Full Text Available This paper demonstrates the first single optical fibre tip probe for concurrent detection of both hydrogen peroxide (H2O2 concentration and pH of a solution. The sensor is constructed by embedding two fluorophores: carboxyperoxyfluor-1 (CPF1 and seminaphtharhodafluor-2 (SNARF2 within a polymer matrix located on the tip of the optical fibre. The functionalised fibre probe reproducibly measures pH, and is able to accurately detect H2O2 over a biologically relevant concentration range. This sensor offers potential for non-invasive detection of pH and H2O2 in biological environments using a single optical fibre.

  8. Towards Fluorescence In Vivo Hybridization (FIVH) Detection of H. pylori in Gastric Mucosa Using Advanced LNA Probes

    DEFF Research Database (Denmark)

    Fontenete, Sílvia; Leite, Marina; Guimarães, Nuno

    2015-01-01

    acid (LNA)/ 2' O-methyl RNA (2'OMe) probe using standard phosphoramidite chemistry and FISH hybridization was then successfully performed both on adhered and suspended bacteria at 37°C. In this work we simplified, shortened and adapted FISH to work at gastric pH values, meaning that the hybridization...... step now takes only 30 minutes and, in addition to the buffer, uses only urea and probe at non-toxic concentrations. Importantly, the sensitivity and specificity of the FISH method was maintained in the range of conditions tested, even at low stringency conditions (e.g., low pH). In conclusion......In recent years, there have been several attempts to improve the diagnosis of infection caused by Helicobacter pylori. Fluorescence in situ hybridization (FISH) is a commonly used technique to detect H. pylori infection but it requires biopsies from the stomach. Thus, the development of an in vivo...

  9. Hyperpolarized NMR Probes for Biological Assays

    Directory of Open Access Journals (Sweden)

    Sebastian Meier

    2014-01-01

    Full Text Available During the last decade, the development of nuclear spin polarization enhanced (hyperpolarized molecular probes has opened up new opportunities for studying the inner workings of living cells in real time. The hyperpolarized probes are produced ex situ, introduced into biological systems and detected with high sensitivity and contrast against background signals using high resolution NMR spectroscopy. A variety of natural, derivatized and designed hyperpolarized probes has emerged for diverse biological studies including assays of intracellular reaction progression, pathway kinetics, probe uptake and export, pH, redox state, reactive oxygen species, ion concentrations, drug efficacy or oncogenic signaling. These probes are readily used directly under natural conditions in biofluids and are often directly developed and optimized for cellular assays, thus leaving little doubt about their specificity and utility under biologically relevant conditions. Hyperpolarized molecular probes for biological NMR spectroscopy enable the unbiased detection of complex processes by virtue of the high spectral resolution, structural specificity and quantifiability of NMR signals. Here, we provide a survey of strategies used for the selection, design and use of hyperpolarized NMR probes in biological assays, and describe current limitations and developments.

  10. Development of innovative pH sensor to evaluate phagocytosis of nanoparticles

    International Nuclear Information System (INIS)

    Leclerc, L; Boudard, D; Pourchez, J; Cottier, M; Marmuse, L; Louis, C; Palle, S; Grosseau, P; Bernache, D

    2011-01-01

    The aim of this work was the development of pH-sensor-NP allowing the quantification of the amount of NP phagocytosed by macrophages. Two types of fluorescent NP with variable and well-characterized sizes and chemicals coatings have been synthesized: - NP with a FITC core (FITC-NP): green fluorescence (control). - FITC-NP functionalized with a pH sensitive probe (pH-sensor-NP): green fluorescence of the FITC and red fluorescence of the pH probe in acidic conditions. Our pH-sensor-NP model was first validated in acellular conditions. They were then incubated with a macrophage cell line allowing distinction and quantification of internalized NP with no major effects on biological toxicity.

  11. Focussed probes ultrasonic follow-up of actual flaw growth during fatigue testing

    International Nuclear Information System (INIS)

    Cinotti, C.; Dufresne, J.; Prot, A.C.; Touffait, A.M.; Saglio, R.

    1979-01-01

    A programme was undertaken to follow-up the growth of actual flaws purposely introduced during the welding process of five test specimens. The aim of this programme is to measure the actual size of the cracks which develop from the known defects during the fatigue testing. The sizing method is based on the use of focussed probes, which allow good accuracy and repeatability, as well as good sensitivity. Examples are given of the first results: sizing before testing, then step by step during the fatigue testing and also under compression. This last point is very important in view of the ultrasonic testing during periodic in-service inspection

  12. Double Layer of a Gold Electrode Probed by AFM Force Measurements

    NARCIS (Netherlands)

    Barten, D.; Kleijn, J.M.; Duval, J.F.L.; Leeuwen, van H.P.; Lyklema, J.; Cohen Stuart, M.A.

    2003-01-01

    Colloidal probe atomic force microscopy was used to determine the electric double layer interactions between a gold electrode and a spherical silica probe. The double layer properties of the gold/solution interface were varied through the pH and salt concentration of the electrolyte, as well as by

  13. A fluorescent probe which allows highly specific thiol labeling at low pH

    DEFF Research Database (Denmark)

    Nielsen, Jonas W.; Jensen, Kristine Steen; Hansen, Rosa E.

    2012-01-01

    and properties of a thiol-specific reagent, fluorescent cyclic activated disulfide (FCAD), which includes the fluorescein moiety as fluorophore and utilizes a variation of thiol-disulfide exchange chemistry. The leaving-group character of FCAD makes it reactive at pH 3, allowing modification at low pH, limiting...

  14. Design and Testing of a Flexible Inclinometer Probe for Model Tests of Landslide Deep Displacement Measurement.

    Science.gov (United States)

    Zhang, Yongquan; Tang, Huiming; Li, Changdong; Lu, Guiying; Cai, Yi; Zhang, Junrong; Tan, Fulin

    2018-01-14

    The physical model test of landslides is important for studying landslide structural damage, and parameter measurement is key in this process. To meet the measurement requirements for deep displacement in landslide physical models, an automatic flexible inclinometer probe with good coupling and large deformation capacity was designed. The flexible inclinometer probe consists of several gravity acceleration sensing units that are protected and positioned by silicon encapsulation, all the units are connected to a 485-comunication bus. By sensing the two-axis tilt angle, the direction and magnitude of the displacement for a measurement unit can be calculated, then the overall displacement is accumulated according to all units, integrated from bottom to top in turn. In the conversion from angle to displacement, two spline interpolation methods are introduced to correct and resample the data; one is to interpolate the displacement after conversion, and the other is to interpolate the angle before conversion; compared with the result read from checkered paper, the latter is proved to have a better effect, with an additional condition that the displacement curve move up half the length of the unit. The flexible inclinometer is verified with respect to its principle and arrangement by a laboratory physical model test, and the test results are highly consistent with the actual deformation of the landslide model.

  15. Quantifying Interfacial pH Variation at Molecular Length Scales Using a Concurrent Non-Faradaic Reaction.

    Science.gov (United States)

    Ryu, Jaeyune; Wuttig, Anna; Surendranath, Yogesh

    2018-05-15

    We quantify changes in the interfacial pH local to the electrochemical double layer during electrocatalysis, using a concurrent non-faradaic probe reaction. In the absence of electrocatalysis, nanostructured Pt/C surfaces mediate the reaction of H2 with cis-2-butene-1,4-diol to form a mixture of 1,4-butanediol and n-butanol with a selectivity that is linearly dependent on the bulk solution pH. We show that kinetic branching occurs from a common surface-bound intermediate, ensuring that this probe reaction is uniquely sensitive to the interfacial pH within molecular length scales of the surface. We use the pH-dependent selectivity of this reaction to track changes in interfacial pH during concurrent hydrogen oxidation electrocatalysis and find that the local pH can vary dramatically, > 3 units, relative to the bulk value even at modest current densities in well-buffered electrolytes. This work highlights the key role that interfacial pH variation plays in modulating inner-sphere electrocatalysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. The acid test of fluoride: how pH modulates toxicity.

    Directory of Open Access Journals (Sweden)

    Ramaswamy Sharma

    2010-05-01

    Full Text Available It is not known why the ameloblasts responsible for dental enamel formation are uniquely sensitive to fluoride (F(-. Herein, we present a novel theory with supporting data to show that the low pH environment of maturating stage ameloblasts enhances their sensitivity to a given dose of F(-. Enamel formation is initiated in a neutral pH environment (secretory stage; however, the pH can fall to below 6.0 as most of the mineral precipitates (maturation stage. Low pH can facilitate entry of F(- into cells. Here, we asked if F(- was more toxic at low pH, as measured by increased cell stress and decreased cell function.Treatment of ameloblast-derived LS8 cells with F(- at low pH reduced the threshold dose of F(- required to phosphorylate stress-related proteins, PERK, eIF2alpha, JNK and c-jun. To assess protein secretion, LS8 cells were stably transduced with a secreted reporter, Gaussia luciferase, and secretion was quantified as a function of F(- dose and pH. Luciferase secretion significantly decreased within 2 hr of F(- treatment at low pH versus neutral pH, indicating increased functional toxicity. Rats given 100 ppm F(- in their drinking water exhibited increased stress-mediated phosphorylation of eIF2alpha in maturation stage ameloblasts (pH<6.0 as compared to secretory stage ameloblasts (pH approximately 7.2. Intriguingly, F(--treated rats demonstrated a striking decrease in transcripts expressed during the maturation stage of enamel development (Klk4 and Amtn. In contrast, the expression of secretory stage genes, AmelX, Ambn, Enam and Mmp20, was unaffected.The low pH environment of maturation stage ameloblasts facilitates the uptake of F(-, causing increased cell stress that compromises ameloblast function, resulting in dental fluorosis.

  17. Ultrasonic immersion probes characterization for use in nondestructive testing according to EN 12668-2:2001

    International Nuclear Information System (INIS)

    Silva, C E R; Alvarenga, A V; Costa-Felix, R P B

    2011-01-01

    Ultrasound is often used as a Non-Destructive Testing (NDT) technique to analyze components and structures to detect internal and surface flaws. To guarantee reliable measurements, it is necessary to calibrate instruments and properly assess related uncertainties. An important device of an ultrasonic instrument system is its probe, which characterization should be performed according to EN 12668-2. Concerning immersion probes beam profile, the parameters to be assessed are beam divergence, focal distance, width, and zone length. Such parameters are determined by scanning a reflector or a hydrophone throughout the transducer beam. Within the present work, a methodology developed at Inmetro's Laboratory of Ultrasound to evaluate relevant beam parameters is presented, based on hydrophone scan. Water bath and positioning system to move the hydrophone were used to perform the scan. Studied probes were excited by a signal generator, and the waterborne signals were detected by the hydrophone and acquired using an oscilloscope. A user-friendly virtual instrument was developed in LabVIEW to automate the system. The initial tests were performed using 1 and 2.25 MHz-ultrasonic unfocused probes (Oe 1.27 cm), and results were consistent with the manufacturer's specifications. Moreover, expanded uncertainties were lower than 6% for all parameters under consideration.

  18. Ultrasonic immersion probes characterization for use in nondestructive testing according to EN 12668-2:2001

    Science.gov (United States)

    Silva, C. E. R.; Alvarenga, A. V.; Costa-Felix, R. P. B.

    2011-02-01

    Ultrasound is often used as a Non-Destructive Testing (NDT) technique to analyze components and structures to detect internal and surface flaws. To guarantee reliable measurements, it is necessary to calibrate instruments and properly assess related uncertainties. An important device of an ultrasonic instrument system is its probe, which characterization should be performed according to EN 12668-2. Concerning immersion probes beam profile, the parameters to be assessed are beam divergence, focal distance, width, and zone length. Such parameters are determined by scanning a reflector or a hydrophone throughout the transducer beam. Within the present work, a methodology developed at Inmetro's Laboratory of Ultrasound to evaluate relevant beam parameters is presented, based on hydrophone scan. Water bath and positioning system to move the hydrophone were used to perform the scan. Studied probes were excited by a signal generator, and the waterborne signals were detected by the hydrophone and acquired using an oscilloscope. A user-friendly virtual instrument was developed in LabVIEW to automate the system. The initial tests were performed using 1 and 2.25 MHz-ultrasonic unfocused probes (Ø 1.27 cm), and results were consistent with the manufacturer's specifications. Moreover, expanded uncertainties were lower than 6% for all parameters under consideration.

  19. A novel pH sensitive water soluble fluorescent nanomicellar sensor for potential biomedical applications.

    Science.gov (United States)

    Georgiev, Nikolai I; Bryaskova, Rayna; Tzoneva, Rumiana; Ugrinova, Iva; Detrembleur, Christophe; Miloshev, Stoyan; Asiri, Abdullah M; Qusti, Abdullah H; Bojinov, Vladimir B

    2013-11-01

    Herein we report on the synthesis and sensor activity of a novel pH sensitive probe designed as highly water-soluble fluorescent micelles by grafting of 1,8-naphthalimide-rhodamine bichromophoric FRET system (RNI) to the PMMA block of a well-defined amphiphilic diblock copolymer-poly(methyl methacrylate)-b-poly(methacrylic acid) (PMMA48-b-PMAA27). The RNI-PMMA48-b-PMAA27 adduct is capable of self-assembling into micelles with a hydrophobic PMMA core, containing the anchored fluorescent probe, and a hydrophilic shell composed of PMAA block. Novel fluorescent micelles are able to serve as a highly sensitive pH probe in water and to internalize successfully HeLa and HEK cells. Furthermore, they showed cell specificity and significantly higher photostability than that of a pure organic dye label such as BODIPY. The valuable properties of the newly prepared fluorescent micelles indicate the high potential of the probe for future biological and biomedical applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Influence of pH on the localized corrosion of iron

    International Nuclear Information System (INIS)

    Webley, R.; Henry, R.

    1986-06-01

    The influence of pH on the pitting corrosion of iron in chloride and sulfate solutions was determined using two artificial pit apparatuses to obtain the pH near the surface of the pit bottom. A glass membrane electrode and an antimony electrode were used to measure pH in the two apparatuses. Using solutions of NaCl and Na 2 SO 4 at current densities of 0.5, 5.0, and 10 mA/cm 2 pH's in the range 5 to 6 were obtained with the first apparatus. The antimony probe did not measure pH accurately in solutions of 1 N NaCl and 1 N Na 2 SO 4 and had an error of approximately 2 pH units. A one-dimensional transport model was developed to predict pH variations around the pit mouth and inside the pit. The validity of this model was not verified due to the relative lack of precision with pH measurement techniques

  1. Surface inspection technique with an eddy current testing array probe

    International Nuclear Information System (INIS)

    Nishimizu, Akira; Endo, Hisashi; Tooma, Masahiro; Otani, Kenichi; Ouchi, Hirofumi; Yoshida, Isao; Nonaka, Yoshio

    2010-01-01

    An eddy current testing (ECT) system has been developed for inspecting weld surfaces of components in the reactor pressure vessel of nuclear plants. The system can be applied to curved surfaces with an ECT array probe, it can discriminate flaws from other signal factors by using a combination of arrayed coils signal-phase. The system is applied to a mock-up of core internal components and the signal discrimination using the signal-phase clearly separated flaw and noise signals. (author)

  2. In Vivo EPR Assessment of pH, pO2, Redox Status, and Concentrations of Phosphate and Glutathione in the Tumor Microenvironment.

    Science.gov (United States)

    Bobko, Andrey A; Eubank, Timothy D; Driesschaert, Benoit; Khramtsov, Valery V

    2018-03-16

    This protocol demonstrates the capability of low-field electron paramagnetic resonance (EPR)-based techniques in combination with functional paramagnetic probes to provide quantitative information on the chemical tumor microenvironment (TME), including pO2, pH, redox status, concentrations of interstitial inorganic phosphate (Pi), and intracellular glutathione (GSH). In particular, an application of a recently developed soluble multifunctional trityl probe provides unsurpassed opportunity for in vivo concurrent measurements of pH, pO2 and Pi in Extracellular space (HOPE probe). The measurements of three parameters using a single probe allow for their correlation analyses independent of probe distribution and time of the measurements.

  3. The acid test of fluoride: how pH modulates toxicity.

    Science.gov (United States)

    Sharma, Ramaswamy; Tsuchiya, Masahiro; Skobe, Ziedonis; Tannous, Bakhos A; Bartlett, John D

    2010-05-28

    It is not known why the ameloblasts responsible for dental enamel formation are uniquely sensitive to fluoride (F(-)). Herein, we present a novel theory with supporting data to show that the low pH environment of maturating stage ameloblasts enhances their sensitivity to a given dose of F(-). Enamel formation is initiated in a neutral pH environment (secretory stage); however, the pH can fall to below 6.0 as most of the mineral precipitates (maturation stage). Low pH can facilitate entry of F(-) into cells. Here, we asked if F(-) was more toxic at low pH, as measured by increased cell stress and decreased cell function. Treatment of ameloblast-derived LS8 cells with F(-) at low pH reduced the threshold dose of F(-) required to phosphorylate stress-related proteins, PERK, eIF2alpha, JNK and c-jun. To assess protein secretion, LS8 cells were stably transduced with a secreted reporter, Gaussia luciferase, and secretion was quantified as a function of F(-) dose and pH. Luciferase secretion significantly decreased within 2 hr of F(-) treatment at low pH versus neutral pH, indicating increased functional toxicity. Rats given 100 ppm F(-) in their drinking water exhibited increased stress-mediated phosphorylation of eIF2alpha in maturation stage ameloblasts (pHdental fluorosis.

  4. Probing and irradiation tests of ALICE pixel chip wafers and sensors

    CERN Document Server

    Cinausero, M; Antinori, F; Chochula, P; Dinapoli, R; Dima, R; Fabris, D; Galet, G; Lunardon, M; Manea, C; Marchini, S; Martini, S; Moretto, S; Pepato, Adriano; Prete, G; Riedler, P; Scarlassara, F; Segato, G F; Soramel, F; Stefanini, G; Turrisi, R; Vannucci, L; Viesti, G

    2004-01-01

    In the framework of the ALICE Silicon Pixel Detector (SPD) project a system dedicated to the tests of the ALICE1LHCb chip wafers has been assembled and is now in use for the selection of pixel chips to be bump-bonded to sensor ladders. In parallel, radiation hardness tests of the SPD silicon sensors have been carried out using the 27 MeV proton beam delivered by the XTU TANDEM accelerator at the SIRAD facility in LNL. In this paper we describe the wafer probing and irradiation set-ups and we report the obtained results. (6 refs).

  5. Nitroimidazoles as hypoxic cell radiosensitizers and hypoxia probes: misonidazole, myths and mistakes.

    Science.gov (United States)

    Wardman, Peter

    2018-03-20

    Nitroimidazoles have been extensively explored as hypoxic cell radiosensitizers but have had limited clinical success, with efficacy restricted by toxicity. However, they have proven clinically useful as probes for tumour hypoxia. Both applications, and probably much of the dose-limiting toxicities, reflect the dominant chemical property of electron affinity or ease of reduction, associated with the nitro substituent in an aromatic structure. This single dominant property affords unusual, indeed extraordinary flexibility in drug or probe design, suggesting further development is possible in spite of earlier limitations, in particular building on the benefit of hindsight and an appreciation of errors made in earlier studies. The most notable errors were: the delay in viewing cellular thiol depletion as a likely common artefact in testing in vitro; slow recognition of pH-driven concentration gradients when compounds were weak acids and bases; and a failure to explore the possible involvement of pH and ascorbate in influencing hypoxia probe binding. The experience points to the need to involve a wider range of expertise than that historically involved in many laboratories when studying the effects of chemicals on radiation response or using diagnostic probes.

  6. Evaluating enzootic bovine leukemia virus infection by means of molecular probe compared with the results of serological tests

    International Nuclear Information System (INIS)

    Reichert, M.; Grundbock, J.; Rulka, J.; Kozaczynska, B.; Stec, J.

    1994-01-01

    The present studies were aimed at determining the relation between the finding obtained by means of serological tests and the specific molecular probe. Serological tests were performed according to the methods recommended by the Polish Ministry of Agriculture; ELISA was run with ''Bioveta'' and ''Rhone Merieux'' kits and the AGID test was performed with EBL antigen made in our laboratory. The molecular probe was prepared from the previously cloned provirus DNA of EBL virus. The EBL provirus was detected in 28 samples taken from 44 randomly selected cows in three herds on which a leukemia eradication programme was in process. Three sera out of 28 positive reacting animals were negative in AGID test and only one serum in ELISA. The results indicate that the use of a specific molecular probe has some advantages in the diagnosis of latent virus infections. Besides, it can be applied in the studies on the pathogenesis of enzootic bovine leukemia. (author). 13 refs, 1 fig., 1 tab

  7. A chromenoquinoline-based fluorescent off-on thiol probe for bioimaging.

    Science.gov (United States)

    Kand, Dnyaneshwar; Kalle, Arunasree Marasanapalli; Varma, Sreejith Jayasree; Talukdar, Pinaki

    2012-03-11

    A new chromenoquinoline-based fluorescent off-on thiol probe 2 is reported. In aqueous buffer solutions at physiological pH, the probe exhibited 223-fold enhancement in fluorescence intensity by a Michael addition of cysteine to the maleimide appended to a chromenoquinoline. Cell permeability and live cell imaging of thiols are also demonstrated. This journal is © The Royal Society of Chemistry 2012

  8. Preliminary test of an imaging probe for nuclear medicine using hybrid pixel detectors

    International Nuclear Information System (INIS)

    Bertolucci, E.; Maiorino, M.; Mettivier, G.; Montesi, M.C.; Russo, P.

    2002-01-01

    We are investigating the feasibility of an intraoperative imaging probe for lymphoscintigraphy with Tc-99m tracer, for sentinel node radioguided surgery, using the Medipix series of hybrid detectors coupled to a collimator. These detectors are pixelated semiconductor detectors bump-bonded to the Medipix1 photon counting read-out chip (64x64 pixel, 170 μm pitch) or to the Medipix2 chip (256x256 pixel, 55 μm pitch), developed by the European Medipix collaboration. The pixel detector we plan to use in the final version of the probe is a semi-insulating GaAs detector or a 1-2 mm thick CdZnTe detector. For the preliminary tests presented here, we used 300-μm thick silicon detectors, hybridized via bump-bonding to the Medipix1 chip. We used a tungsten parallel-hole collimator (7 mm thick, matrix array of 64x64 100 μm circular holes with 170 μm pitch), and a 22, 60 and 122 keV point-like (1 mm diameter) radioactive sources, placed at various distances from the detector. These tests were conducted in order to investigate the general feasibility of this imaging probe and its resolving power. Measurements show the high resolution but low efficiency performance of the detector-collimator set, which is able to image the 122 keV source with <1 mm FWHM resolution

  9. Microarray of DNA probes on carboxylate functional beads surface

    Institute of Scientific and Technical Information of China (English)

    黄承志; 李原芳; 黄新华; 范美坤

    2000-01-01

    The microarray of DNA probes with 5’ -NH2 and 5’ -Tex/3’ -NH2 modified terminus on 10 um carboxylate functional beads surface in the presence of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) is characterized in the preseni paper. it was found that the microarray capacity of DNA probes on the beads surface depends on the pH of the aqueous solution, the concentra-tion of DNA probe and the total surface area of the beads. On optimal conditions, the minimum distance of 20 mer single-stranded DNA probe microarrayed on beads surface is about 14 nm, while that of 20 mer double-stranded DNA probes is about 27 nm. If the probe length increases from 20 mer to 35 mer, its microarray density decreases correspondingly. Mechanism study shows that the binding mode of DNA probes on the beads surface is nearly parallel to the beads surface.

  10. Microarray of DNA probes on carboxylate functional beads surface

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The microarray of DNA probes with 5′-NH2 and 5′-Tex/3′-NH2 modified terminus on 10 m m carboxylate functional beads surface in the presence of 1-ethyl-3-(3-dimethylaminopropyl)- carbodiimide (EDC) is characterized in the present paper. It was found that the microarray capacity of DNA probes on the beads surface depends on the pH of the aqueous solution, the concentration of DNA probe and the total surface area of the beads. On optimal conditions, the minimum distance of 20 mer single-stranded DNA probe microarrayed on beads surface is about 14 nm, while that of 20 mer double-stranded DNA probes is about 27 nm. If the probe length increases from 20 mer to 35 mer, its microarray density decreases correspondingly. Mechanism study shows that the binding mode of DNA probes on the beads surface is nearly parallel to the beads surface.

  11. Development and testing of an ion probe for tightly-bunched particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, M.; Pasour, J.

    1996-06-01

    Many high-energy physics experiments require a high-quality and well-diagnosed charged-particle beam (CPB). Precise knowledge of beam size, position, and charge distribution is often crucial to the success of the experiment. It is also important in many applications that the diagnostic used to determine the beam parameters be nonintercepting and nonperturbing. This requirement rules out many diagnostics, such as wire scanners, thin foils which produce Cerenkov or transition radiation, and even some rf cavity diagnostics. Particularly difficult to diagnose are tightly-focused (r{sub b} << 1 mm), short-duration (psec) beams, such as those in state-of-the-art or next-generation particle colliders. In this paper we describe an ion probe that is capable of penetrating the space-charge field of densely bunched CPBs without perturbation, thereby enabling the measurement of the microstructure of the bunch. This diagnostic probe uses a finely-focused stream of ions to interact with the CPB. Related techniques have been discussed in the literature. In fact, the present work evolved from an electron deflection diagnostic for CPBs that we previously described. A similar electron probe was tested even earlier at TRIUMF and in the Former Soviet Union. Electron probes have also been used to measure plasma sheaths and potentials and the neutralization of heavy ion beams. Also, Mendel has used an ion beam (22 keV He{sup +}) to probe rapidly varying fields in plasmas. The probe ions are injected across the beam tube and into the path of the high-energy CPB. The ions are deflected by the CPB, and the direction and magnitude of the deflection are directly related to the spatial and temporal charge distribution of the CPB. Easily-resolved deflections can be produced by microbunches having total charge on the order of a nCoul and pulse durations of a few psec. The deflected ions are monitored with a suitable detector, in this case a microchannel plate capable of detecting single ions.

  12. The effect of probe choice and solution conditions on the apparent photoreactivity of dissolved organic matter.

    Science.gov (United States)

    Maizel, Andrew C; Remucal, Christina K

    2017-08-16

    Excited triplet states of dissolved organic matter ( 3 DOM) are quantified directly with the species-specific probes trans,trans-hexadienoic acid (HDA) and 2,4,6-trimethylphenol (TMP), and indirectly with the singlet oxygen ( 1 O 2 ) probe furfuryl alcohol (FFA). Although previous work suggests that these probe compounds may be sensitive to solution conditions, including dissolved organic carbon concentration ([DOC]) and pH, and may quantify different 3 DOM subpopulations, the probes have not been systematically compared. Therefore, we quantify the apparent photoreactivity of diverse environmental waters using HDA, TMP, and FFA. By conducting experiments under ambient [DOC] and pH, with standardized [DOC] and pH, and with solid phase extraction isolates, we demonstrate that much of the apparent dissimilarity in photochemical measurements is attributable to solution conditions, rather than intrinsic differences in 3 DOM production. In general, apparent quantum yields (Φ 1 O 2 ≥ Φ 3 DOM,TMP ≫ Φ 3 DOM,HDA ) and pseudo-steady state concentrations ([ 1 O 2 ] ss > [ 3 DOM] ss,TMP > [ 3 DOM] ss,HDA ) show consistent relationships in all waters under standardized conditions. However, intrinsic differences in 3 DOM photoreactivity are apparent between DOM from diverse sources, as seen in the higher Φ 1 O 2 and lower Φ 3 DOM,TMP of wastewater effluents compared with oligotrophic lakes. Additionally, while conflicting trends in photoreactivity are observed under ambient conditions, all probes observe quantum yields increasing from surface wetlands to terrestrially influenced waters to oligotrophic lakes under standardized conditions. This work elucidates how probe selection and solution conditions influence the apparent photoreactivity of environmental waters and confirms that 3 DOM or 1 O 2 probes cannot be used interchangeably in waters that vary in [DOC], pH, or DOM source.

  13. Measurement of the Extracellular pH of Adherently Growing Mammalian Cells with High Spatial Resolution Using a Voltammetric pH Microsensor.

    Science.gov (United States)

    Munteanu, Raluca-Elena; Stǎnicǎ, Luciana; Gheorghiu, Mihaela; Gáspár, Szilveszter

    2018-05-15

    There are only a few tools suitable for measuring the extracellular pH of adherently growing mammalian cells with high spatial resolution, and none of them is widely used in laboratories around the world. Cell biologists very often limit themselves to measuring the intracellular pH with commercially available fluorescent probes. Therefore, we built a voltammetric pH microsensor and investigated its suitability for monitoring the extracellular pH of adherently growing mammalian cells. The voltammetric pH microsensor consisted of a 37 μm diameter carbon fiber microelectrode modified with reduced graphene oxide and syringaldazine. While graphene oxide was used to increase the electrochemically active surface area of our sensor, syringaldazine facilitated pH sensing through its pH-dependent electrochemical oxidation and reduction. The good sensitivity (60 ± 2.5 mV/pH unit), reproducibility (coefficient of variation ≤3% for the same pH measured with 5 different microsensors), and stability (pH drift around 0.05 units in 3 h) of the built voltammetric pH sensors were successfully used to investigate the acidification of the extracellular space of both cancer cells and normal cells. The results indicate that the developed pH microsensor and the perfected experimental protocol based on scanning electrochemical microscopy can reveal details of the pH regulation of cells not attainable with pH sensors lacking spatial resolution or which cannot be reproducibly positioned in the extracellular space.

  14. Electrochemical behavior and pH stability of artificial salivas for corrosion tests.

    Science.gov (United States)

    Queiroz, Gláucia Maria Oliveira de; Silva, Leandro Freitas; Ferreira, José Tarcísio Lima; Gomes, José Antônio da Cunha P; Sathler, Lúcio

    2007-01-01

    It is assumed that the compositions of artificial salivas are similar to that of human saliva. However, the use of solutions with different compositions in in vitro corrosion studies can lead dissimilar electrolytes to exhibit dissimilar corrosivity and electrochemical stability. This study evaluated four artificial salivas as regards pH stability with time, redox potentials and the polarization response of an inert platinum electrode. The tested solutions were: SAGF medium, Mondelli artificial saliva, UFRJ artificial saliva (prepared at the School of Pharmacy, Federal University of Rio de Janeiro, RJ, Brazil) and USP-RP artificial saliva (prepared at the School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, SP, Brazil). It was observed that pH variations were less than 1 unit during a 50-hour test. The SAGF medium, and the UFRJ and USP-RP solutions exhibited more oxidizing characteristics, whereas the Mondelli solution presented reducing properties. Anodic polarization revealed oxidation of the evaluated electrolytes at potentials below +600 mV SCE. It was observed that the UFRJ and USP-RP solutions presented more intense oxidation and reduction processes as compared to the Mondelli and SAGF solutions.

  15. Determination of Peroxisomal pH in Living Mammalian Cells Using pHRed.

    Science.gov (United States)

    Godinho, Luis F; Schrader, Michael

    2017-01-01

    Organelle pH homeostasis is crucial for maintaining proper cellular function. The nature of the peroxisomal pH remains somewhat controversial, with several studies reporting conflicting results. Here, we describe in detail a rapid and accurate method for the measurement of peroxisomal pH, using the pHRed sensor protein and confocal microscopy of living mammalian cells. pHRed, a ratiometric sensor of pH, is targeted to the peroxisomes by virtue of a C-terminal targeting sequence. The probe has a maximum fluorescence emission at 610 nm while exhibiting dual excitation peaks at 440 and 585 nm, allowing for ratiometric imaging and determination of intracellular pH in live cell microscopy.

  16. Characterization of axial probes used in eddy current testing

    International Nuclear Information System (INIS)

    Wache, G.; Nourrisson, Ph.; Garet, Th.

    2001-01-01

    Customized reference tubes reduced sensitivity discrepancies able to be observed from one probe to the other, due to the gain setting adjustment required for a pre-definite level in amplitude response of the artificial notch. The use of a reference circuit in place of a reference part, makes characterization of the probe matched to its generator more accurate: - the material dependence is cancelled during the compensation process, - the reference signal can be adjusted more accurately in amplitude and phase response, - the manufacturing cost is reduced compared to the one necessary for machining the reference part, - the amplitude and phase response of the reference circuit can be simply modelled by using the transformer relations, such as one can appreciate the variations of the probe definition parameters and its connexion to the generator, and makes them optimal for use. The method proposed by ALSTOM for the characterization of the condenser and exchanger tubing probes, takes in account the amplitude and phase response of a reference circuit versus frequency, such it can be done by using SURECA tubing provided by ASCOT: it allows to control that the frequency values of the probe required for use are inside the useful bandwidth defined by the - 6 dB attenuation from the maximum amplitude response of the reference circuit versus frequency. Examples coming from measurements done among more than 200 probes, for which faults have been observed and replacements made by the manufacturer, are displayed and commented. (authors)

  17. ATHLET calculations of the pressurizer surge line break (PH-SLB test) at the PMK-2 test facility

    International Nuclear Information System (INIS)

    Krepper, E.; Schaefer, F.

    2000-01-01

    At the Hungarian integral test facility PMK-2 a pressurizer surge line break experiment (PH-SLB test) was carried out with the PHARE 4.2.6b project. The primary objective of the test was to provide experimental data for a surge line break transient at VVER-440 reactors with reduced injection from the emergency core cooling systems (ECC). At the Institute of Safety Research calculations of the experiment were performed with the thermohydraulic computer code ATHLET, which was developed by GRS (Gesellschaft fuer Anlagen- und Reaktorsicherheit) mbH. In the context of the PHARE 4.2.6b project the Institute of Safety Research has also supplied the void fraction measurement system for the PMK-2 test facility and was involved in the evaluation of the experimental results. (orig.)

  18. University scientists test Mars probe equipment

    CERN Multimedia

    2002-01-01

    Scientists at Leicester University have spent four years researching and designing the Flight Model Position Adjustable Workbench (PAW) at the university. It will be attached to the Beagle 2 probe before being sent to the Red Planet in the spring (1/2 page).

  19. Transmit-receive eddy current probes

    International Nuclear Information System (INIS)

    Obrutsky, L.S.; Sullivan, S.P.; Cecco, V.S.

    1997-01-01

    In the last two decades, due to increased inspection demands, eddy current instrumentation has advanced from single-frequency, single-output instruments to multifrequency, computer-aided systems. This has significantly increased the scope of eddy current testing, but, unfortunately, it has also increased the cost and complexity of inspections. In addition, this approach has not always improved defect detectability or signal-to-noise. Most eddy current testing applications are still performed with impedance probes, which have well known limitations. However, recent research at AECL has led to improved eddy current inspections through the design and development of transmit-receive (T/R) probes. T/R eddy current probes, with laterally displaced transmit and receive coils, present a number of advantages over impedance probes. They have improved signal-to-noise ratio in the presence of variable lift-off compared to impedance probes. They have strong directional properties, permitting probe optimization for circumferential or axial crack detection, and possess good phase discrimination to surface defects. They can significantly increase the scope of eddy current testing permitting reliable detection and sizing of cracks in heat exchanger tubing as well as in welded areas of both ferritic and non-ferromagnetic components. This presentation will describe the operating principles of T/R probes with the help of computer-derived normalized voltage diagrams. We will discuss their directional properties and analyze the advantages of using single and multiple T/R probes over impedance probes for specific inspection cases. Current applications to surface and tube testing and some typical inspection results will be described. (author)

  20. Integration and validation testing for PhEDEx, DBS and DAS with the PhEDEx LifeCycle agent

    International Nuclear Information System (INIS)

    Boeser, C; Chwalek, T; Giffels, M; Kuznetsov, V; Wildish, T

    2014-01-01

    The ever-increasing amount of data handled by the CMS dataflow and workflow management tools poses new challenges for cross-validation among different systems within CMS experiment at LHC. To approach this problem we developed an integration test suite based on the LifeCycle agent, a tool originally conceived for stress-testing new releases of PhEDEx, the CMS data-placement tool. The LifeCycle agent provides a framework for customising the test workflow in arbitrary ways, and can scale to levels of activity well beyond those seen in normal running. This means we can run realistic performance tests at scales not likely to be seen by the experiment for some years, or with custom topologies to examine particular situations that may cause concern some time in the future. The LifeCycle agent has recently been enhanced to become a general purpose integration and validation testing tool for major CMS services. It allows cross-system integration tests of all three components to be performed in controlled environments, without interfering with production services. In this paper we discuss the design and implementation of the LifeCycle agent. We describe how it is used for small-scale debugging and validation tests, and how we extend that to large-scale tests of whole groups of sub-systems. We show how the LifeCycle agent can emulate the action of operators, physicists, or software agents external to the system under test, and how it can be scaled to large and complex systems.

  1. Integration and validation testing for PhEDEx, DBS and DAS with the PhEDEx LifeCycle agent

    Science.gov (United States)

    Boeser, C.; Chwalek, T.; Giffels, M.; Kuznetsov, V.; Wildish, T.

    2014-06-01

    The ever-increasing amount of data handled by the CMS dataflow and workflow management tools poses new challenges for cross-validation among different systems within CMS experiment at LHC. To approach this problem we developed an integration test suite based on the LifeCycle agent, a tool originally conceived for stress-testing new releases of PhEDEx, the CMS data-placement tool. The LifeCycle agent provides a framework for customising the test workflow in arbitrary ways, and can scale to levels of activity well beyond those seen in normal running. This means we can run realistic performance tests at scales not likely to be seen by the experiment for some years, or with custom topologies to examine particular situations that may cause concern some time in the future. The LifeCycle agent has recently been enhanced to become a general purpose integration and validation testing tool for major CMS services. It allows cross-system integration tests of all three components to be performed in controlled environments, without interfering with production services. In this paper we discuss the design and implementation of the LifeCycle agent. We describe how it is used for small-scale debugging and validation tests, and how we extend that to large-scale tests of whole groups of sub-systems. We show how the LifeCycle agent can emulate the action of operators, physicists, or software agents external to the system under test, and how it can be scaled to large and complex systems.

  2. Mechanistic studies of the genetically encoded fluorescent protein voltage probe ArcLight.

    Directory of Open Access Journals (Sweden)

    Zhou Han

    Full Text Available ArcLight, a genetically encoded fluorescent protein voltage probe with a large ΔF/ΔV, is a fusion between the voltage sensing domain of the Ciona instestinalis voltage sensitive phosphatase and super ecliptic pHluorin carrying a single mutation (A227D in the fluorescent protein. Without this mutation the probe produces only a very small change in fluorescence in response to voltage deflections (∼ 1%. The large signal afforded by this mutation allows optical detection of action potentials and sub-threshold electrical events in single-trials in vitro and in vivo. However, it is unclear how this single mutation produces a probe with such a large modulation of its fluorescence output with changes in membrane potential. In this study, we identified which residues in super ecliptic pHluorin (vs eGFP are critical for the ArcLight response, as a similarly constructed probe based on eGFP also exhibits large response amplitude if it carries these critical residues. We found that D147 is responsible for determining the pH sensitivity of the fluorescent protein used in these probes but by itself does not result in a voltage probe with a large signal. We also provide evidence that the voltage dependent signal of ArcLight is not simply sensing environmental pH changes. A two-photon polarization microscopy study showed that ArcLight's response to changes in membrane potential includes a reorientation of the super ecliptic pHluorin. We also explored different changes including modification of linker length, deletion of non-essential amino acids in the super ecliptic pHluorin, adding a farnesylation site, using tandem fluorescent proteins and other pH sensitive fluorescent proteins.

  3. Lepton Flavour Universality tests in $B$ decays as a probe for New Physics arXiv

    CERN Document Server

    INSPIRE-00003200

    In the Standard Model (SM), the coupling of the electroweak gauge bosons to the leptons is lepton flavour universal. Tests of this property constitute sensitive probes for new physics models that violate lepton flavour universality. Recent tests of lepton universality in rare $b\\to s\\ell\\ell$ decays and semileptonic $b\\to c\\tau\\bar{\

  4. Radiological demonstration of gastroesophageal reflux. Diagnostic value of barium and bread studies compared with 24-hour pH monitoring

    International Nuclear Information System (INIS)

    Aksglaede, K.; Funch-Jensen, P.; Thommesen, P.

    1999-01-01

    To correlate gastroesophageal reflux (GER), demonstrated by a radiological method using food, with the reflux events, as determined by 24-h pH monitoring. One hundred and seventeen patients with a median age of 47 years (86 male and 31 female) were examined. In the supine left position, the patient consumed 360 ml of barium contrast. Fluoroscopy was performed with the patient in the supine right oblique position during mastication and swallowing a piece of rye bread with liver pate and barium. The test was positive if barium was observed >= 5 cm proximal to the gastroesophageal junction. An antimony pH-probe was placed 5 cm above the lower esophageal sphincter, previously determined by manometry. The position was controlled by radiography after positioning and before removal. The total time of esophageal pH<4 exceeding 5.0% was considered pathological. The radiological method had a specificity of 100% and a sensitivity of 52% compared to 24-h pH monitoring. The high specificity of this radiological method justify direct therapeutic consequence of a positive test. However, a negative test still renders the problem unsolved

  5. Radiological demonstration of gastroesophageal reflux. Diagnostic value of barium and bread studies compared with 24-hour pH monitoring

    International Nuclear Information System (INIS)

    Aksglaede, K.; Thommesen, P.; Funch-Jensen, P.

    1999-01-01

    Purpose: To correlate gastroesophageal reflux (GER), demonstrated by a radiological method using food, with the reflux events, as determined by 24-h pH monitoring. Material and Methods: One hundred and seventeen patients with a median age of 47 years (86 male and 31 female) were examinated. In the supine left position, the patient consumed 360 ml of barium contrast. Fluoroscopy was performed with the patient in the supine right oblique position during mastication and swallowing a piece of rye bread with liver pate and barium. The test was positive if barium was observed ≥5 cm proximal to the gastroesophageal junction. An antimony pH-probe was placed 5 cm above the lower esophageal sphincter, previously determined by manometry. The position was controlled by radiography after positioning and before removal. The total time of esophageal pH<4 exceeding 5.0% was considered pathological. Results: The radiological method had a specificity of 100% and a sensitivity of 52% compared to 24-h pH monitoring. Conclusion: The high specificity of this radiological method justify direct therapeutic consequence of a positive test. However, a negative test still renders the problem unsolved. (orig.)

  6. Radiological demonstration of gastroesophageal reflux. Diagnostic value of barium and bread studies compared with 24-hour pH monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Aksglaede, K.; Thommesen, P. [Dept. of Diagnostic Radiology R, Aarhus Univ. Hospital, Aarhus (Denmark); Funch-Jensen, P. [Surgical Gastroenterology L, Aarhus Univ. Hospital, Aarhus (Denmark)

    1999-11-01

    Purpose: To correlate gastroesophageal reflux (GER), demonstrated by a radiological method using food, with the reflux events, as determined by 24-h pH monitoring. Material and Methods: One hundred and seventeen patients with a median age of 47 years (86 male and 31 female) were examinated. In the supine left position, the patient consumed 360 ml of barium contrast. Fluoroscopy was performed with the patient in the supine right oblique position during mastication and swallowing a piece of rye bread with liver pate and barium. The test was positive if barium was observed {>=}5 cm proximal to the gastroesophageal junction. An antimony pH-probe was placed 5 cm above the lower esophageal sphincter, previously determined by manometry. The position was controlled by radiography after positioning and before removal. The total time of esophageal pH<4 exceeding 5.0% was considered pathological. Results: The radiological method had a specificity of 100% and a sensitivity of 52% compared to 24-h pH monitoring. Conclusion: The high specificity of this radiological method justify direct therapeutic consequence of a positive test. However, a negative test still renders the problem unsolved. (orig.)

  7. Valve for the mechanical isolation of a pipe to take up a test probe

    International Nuclear Information System (INIS)

    Uecker, D.F.

    1976-01-01

    A valve is introduced for application in a pipe in which a test probe is arranged. The valve serves to isolate the pipe in a gas-tight way, thus preventing the escape of radioactive gas or dust during operation in a nuclear reactor. (TK) [de

  8. Command and Data Handling Flight Software test framework: A Radiation Belt Storm Probes practice

    Science.gov (United States)

    Hill, T. A.; Reid, W. M.; Wortman, K. A.

    During the Radiation Belt Storm Probes (RBSP) mission, a test framework was developed by the Embedded Applications Group in the Space Department at the Johns Hopkins Applied Physics Laboratory (APL). The test framework is implemented for verification of the Command and Data Handling (C& DH) Flight Software. The RBSP C& DH Flight Software consists of applications developed for use with Goddard Space Flight Center's core Flight Executive (cFE) architecture. The test framework's initial concept originated with tests developed for verification of the Autonomy rules that execute with the Autonomy Engine application of the RBSP C& DH Flight Software. The test framework was adopted and expanded for system and requirements verification of the RBSP C& DH Flight Software. During the evolution of the RBSP C& DH Flight Software test framework design, a set of script conventions and a script library were developed. The script conventions and library eased integration of system and requirements verification tests into a comprehensive automated test suite. The comprehensive test suite is currently being used to verify releases of the RBSP C& DH Flight Software. In addition to providing the details and benefits of the test framework, the discussion will include several lessons learned throughout the verification process of RBSP C& DH Flight Software. Our next mission, Solar Probe Plus (SPP), will use the cFE architecture for the C& DH Flight Software. SPP also plans to use the same ground system as RBSP. Many of the RBSP C& DH Flight Software applications are reusable on the SPP mission, therefore there is potential for test design and test framework reuse for system and requirements verification.

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

    Directory of Open Access Journals (Sweden)

    ABDOU MBAYE

    2014-08-01

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

  10. Design and Investigation of Optical Properties of N-(Rhodamine-B)-Lactam-Ethylenediamine (RhB-EDA) Fluorescent Probe.

    Science.gov (United States)

    Soršak, Eva; Volmajer Valh, Julija; Korent Urek, Špela; Lobnik, Aleksandra

    2018-04-14

    This study presents chemical modification of a Rhodamine B (RhB) sensor probe by ethylenediamine (EDA), and investigation of its spectral as well as sensor properties to the various metals. The synthesised N -(Rhodamine-B)-lactam-ethylenediamine (RhB-EDA) fluorescent probe shows interesting optical sensor properties, and high sensitivity and selectivity to Ag⁺ ions among all the tested metal ions (K⁺, Mg 2+ , Cu 2+ , Ni 2+ , Fe 2+ , Pb 2+ , Na⁺, Mn 2+ , Li⁺, Al 3+ , Co 2+ , Hg 2+ , Sr 2+ , Ca 2+ , Ag⁺, Cd 2+ and Zn 2+ ), while the well-known Rhodamine B (RhB) fluorescent probe shows much less sensitivity to Ag⁺ ions, but high sensitivity to Fe 2+ ions. The novel fluorescent sensor probe RhB-EDA has the capabilities to sense Ag⁺ ions up to µM ranges by using the fluorescence quenching approach. The probe displayed a dynamic response to Ag⁺ in the range of 0.43 × 10 -3 -10 -6 M with a detection limit of 0.1 μM. The sensing system of an RhB-EDA novel fluorescent probe was optimised according to the spectral properties, effect of pH and buffer, photostability, incubation time, sensitivity, and selectivity. Since all the spectral and sensing properties were tested in green aqueous media, although many other similar sensor systems rely on organic solvent solutions, the RhB-EDA sensing probe may be a good candidate for measuring Ag⁺ ions in real-life applications.

  11. Testing the stability of magnetic iron oxides/kaolinite nanocomposite under various pH conditions

    Science.gov (United States)

    Tokarčíková, Michaela; Tokarský, Jonáš; Kutláková, Kateřina Mamulová; Seidlerová, Jana

    2017-09-01

    Magnetically modified clays containing iron oxides nanoparticles (FexOy NPs) are low-cost and environmentally harmless materials suitable for sorption of pollutants from wastewaters. Stability of this smart material was evaluated both experimentally and theoretically using molecular modelling. Original kaolinite and prepared FexOy/kaolinite nanocomposite were characterized using X-ray fluorescence spectroscopy, X-ray powder diffraction, infrared spectroscopy, and transmission electron microscopy, and the stability was studied using leaching tests performed according to the European technical standard EN 12457-2 in deionized water and extraction agents with varying pH (2, 4, 9, and 11). The influence of pH on amount of FexOy NPs released from the composite and amount of the basic elements released from the kaolinite structure was studied using inductively coupled plasma atomic emission spectroscopy. All experiments proved that the magnetic properties of the nanocomposite will not change even after leaching in extraction agents with various pH.

  12. Intensity response function of the photopic negative response (PhNR): effect of age and test-retest reliability.

    Science.gov (United States)

    Joshi, Nabin R; Ly, Emma; Viswanathan, Suresh

    2017-08-01

    To assess the effect of age and test-retest reliability of the intensity response function of the full-field photopic negative response (PhNR) in normal healthy human subjects. Full-field electroretinograms (ERGs) were recorded from one eye of 45 subjects, and 39 of these subjects were tested on two separate days with a Diagnosys Espion System (Lowell, MA, USA). The visual stimuli consisted of brief (test-retest reliability was assessed with the Wilcoxon signed-rank test and Bland-Altman analysis. Holm's correction was applied to account for multiple comparisons. V max of BT was significantly smaller than that of PT and b-wave, and the V max of PT and b-wave was not significantly different from each other. The slope parameter n was smallest for BT and the largest for b-wave and the difference between the slopes of all three measures were statistically significant. Small differences observed in the mean values of K for the different measures did not reach statistical significance. The Wilcoxon signed-rank test indicated no significant differences between the two test visits for any of the Naka-Rushton parameters for the three ERG measures, and the Bland-Altman plots indicated that the mean difference between test and retest measurements of the different fit parameters was close to zero and within 6% of the average of the test and retest values of the respective parameters for all three ERG measurements, indicating minimal bias. While the coefficient of reliability (COR, defined as 1.96 times the standard deviation of the test and retest difference) of each fit parameter was more or less comparable across the three ERG measurements, the %COR (COR normalized to the mean test and retest measures) was generally larger for BT compared to both PT and b-wave for each fit parameter. The Naka-Rushton fit parameters did not show statistically significant changes with age for any of the ERG measures when corrections were applied for multiple comparisons. However, the V max of

  13. Removing Eddy-current probe wobble noise from steam generator tubes testing using wavelet transform

    International Nuclear Information System (INIS)

    Lopez, Luiz Antonio Negro Martin; Ting, Daniel Kao Sun; Upadhyaya, Belle R.

    2005-01-01

    One of the most import nondestructive evaluation (NDE) applied to steam generator tubes inspection is the electromagnetic Eddy-Current testing (ECT). The signals generated in this NDE, in general, contain many noises which make difficult the interpretation and analysis of ECT signals. One of the noises present in the signals is the probe wobble noise, which is caused by the existing slack between the probe and the tube. In this work, Wavelet Transform (WT) is used in the probe wobble de-noising. WT is a relatively recent mathematical tool, which allows local analysis of non stationary signals such as ECT signals. This is a great advantage of WT when compared with other analysis tools such as Fourier Transform. However, using WT involves wavelets and coefficients selection as well as choosing the number of decomposition level needed. This work presents a probe wobble de-noising method when used in conjunction with the traditional ECT evaluation. Comparative results using several WT applied do Eddy-Current signals are presented in a reliable way, in other words, without loss of inherent defect information. A stainless steel tube, with 2 artificial defects generated by electro-erosion, was inspected by a ZETEC MIZ-17ET ECT equipment. The signals were de-noised through several different WT and the results are presented. The method offer good results and is a promising method because allows for the removal of Eddy-Current signals probe wobble effect without loss of essential signal information. (author)

  14. Esophageal pH monitoring

    Science.gov (United States)

    pH monitoring - esophageal; Esophageal acidity test ... Esophageal pH monitoring is used to check how much stomach acid is entering the esophagus. It also checks how well the acid is cleared downward into the ...

  15. Efficiency of the Needle Probe Test for Evaluation of Thermal Conductivity of Composite Materials: Two-Scale Analysis

    Directory of Open Access Journals (Sweden)

    Łydżba Dariusz

    2014-03-01

    Full Text Available The needle probe test, as a thermal conductivity measurement method, has become very popular in recent years. In the present study, the efficiency of this methodology, for the case of composite materials, is investigated based on the numerical simulations. The material under study is a two-phase composite with periodic microstructure of “matrix-inclusion” type. Two-scale analysis, incorporating micromechanics approach, is performed. First, the effective thermal conductivity of the composite considered is found by the solution of the appropriate boundary value problem stated for the single unit cell. Next, numerical simulations of the needle probe test are carried out. In this case, two different locations of the measuring sensor are considered. It is shown that the “equivalent” conductivity, derived from the probe test, is strongly affected by the location of the sensor. Moreover, comparing the results obtained for different scales, one can notice that the “equivalent” conductivity cannot be interpreted as the effective one for the composites considered. Hence, a crude approximation of the effective property is proposed based on the volume fractions of constituents and the equivalent conductivities derived from different sensor locations.

  16. Field Testing of an In-well Point Velocity Probe for the Rapid Characterization of Groundwater Velocity

    Science.gov (United States)

    Osorno, T.; Devlin, J. F.

    2017-12-01

    Reliable estimates of groundwater velocity is essential in order to best implement in-situ monitoring and remediation technologies. The In-well Point Velocity Probe (IWPVP) is an inexpensive, reusable tool developed for rapid measurement of groundwater velocity at the centimeter-scale in monitoring wells. IWPVP measurements of groundwater speed are based on a small-scale tracer test conducted as ambient groundwater passes through the well screen and the body of the probe. Horizontal flow direction can be determined from the difference in tracer mass passing detectors placed in four funnel-and-channel pathways through the probe, arranged in a cross pattern. The design viability of the IWPVP was confirmed using a two-dimensional numerical model in Comsol Multiphysics, followed by a series of laboratory tank experiments in which IWPVP measurements were calibrated to quantify seepage velocities in both fine and medium sand. Lab results showed that the IWPVP was capable of measuring the seepage velocity in less than 20 minutes per test, when the seepage velocity was in the range of 0.5 to 4.0 m/d. Further, the IWPVP estimated the groundwater speed with a precision of ± 7%, and an accuracy of ± 14%, on average. The horizontal flow direction was determined with an accuracy of ± 15°, on average. Recently, a pilot field test of the IWPVP was conducted in the Borden aquifer, C.F.B. Borden, Ontario, Canada. A total of approximately 44 IWPVP tests were conducted within two 2-inch groundwater monitoring wells comprising a 5 ft. section of #8 commercial well screen. Again, all tests were completed in under 20 minutes. The velocities estimated from IWPVP data were compared to 21 Point Velocity Probe (PVP) tests, as well as Darcy-based estimates of groundwater velocity. Preliminary data analysis shows strong agreement between the IWPVP and PVP estimates of groundwater velocity. Further, both the IWPVP and PVP estimates of groundwater velocity appear to be reasonable when

  17. Measurement of peritoneal fluid pH in patients with non-serosal invasive gastric cancer.

    Science.gov (United States)

    Noh, Seung Moo

    2003-02-01

    The accurate pH range of peritoneal fluid is clinically valuable for the evaluation of some pathological conditions of the body, however, it is not easy to measure in healthy individuals. The aim of this study was to measure; pH, pCO2, pO2, Na+, K++, Ca++, HCO3-, and O2 saturation of the peritoneal fluid in patients with non-serosal invasive gastric cancer. One hundred and thirty four patients (86 men and 48 women), ranging in age from 24 to 91 years were enrolled in this study. After opening the abdominal wall, the probe of a portable pH meter was placed in the peritoneal fluid in the subhepatic space. In addition, I collected the peritoneal fluid from the subhepatic space to measure, pH, pCO2, pO2, Na+, K++, Ca++, HCO3-, and O2 saturation using an autoanalyzer. The pHs of the peritoneal fluids tested has a mean of 7.73 (range 7.46 - 8.10), and the other parameters were pCO2, 22.81 mmHg; pO2, 136.49 mmHg; Na+, 146.57 mmol/L; K++, 4.80 mmol/L; Ca++, 0.89 mmol/L; HCO3-, 30.54 mmol/L, and O2 saturation, 99.74%. This study describes a practical method of measuring the pH of peritoneal fluid. The result obtained reflects the normal adult peritoneal pH value, which I propose as a reference value.

  18. [The Additional Role of Symptom-Reflux Association Analysis of Diagnosis of Gastroesophageal Reflux Disease Using Bravo Capsule pH Test].

    Science.gov (United States)

    Jung, Kyoungwon; Park, Moo In; Park, Seun Ja; Moon, Won; Kim, Sung Eun; Kim, Jae Hyun

    2017-10-25

    Since the development of ambulatory esophageal pH monitoring test to diagnose gastroesophageal reflux disease (GERD), several parameters have been introduced. The aim of this study was to assess whether using the symptom index (SI), symptom sensitivity index (SSI), and symptom association probability (SAP), in addition to the DeMeester score (DS), would be useful for interpreting the Bravo pH monitoring test. A retrospective study, which included 68 patients with reflux symptoms refractory to proton pump inhibitor (PPI) therapy who underwent a Bravo capsule pH test between October 2006 and May 2015, was carried out. Acid reflux parameters and symptom reflux association parameters were analyzed. The median percent time of total pHvariation in percent time of total pHpH test, diagnosis of GERD, including reflux hypersensitivity, can be improved by performing an analysis of the symptom-reflux association and of the day-to-day variation.

  19. Trihydroxytrioxatriangulene - An Extended Fluorescein and a Ratiometric pH Sensor

    DEFF Research Database (Denmark)

    Westerlund, Fredrik; Hildebrandt, Christoffer Boli; Sørensen, Thomas Just

    2010-01-01

    Fluorescein ver. 2.0: A new, highly fluorescent, pH-sensitive trihydroxytrioxatriangulenium dye (H-TOTA) has been synthesised and characterised. The dye is closely related to fluorescein and may be considered to be a two-dimensional extended version. This new dye can exist in four different proto...... protonation states (see graphic) depending on the pH, and its use as a sensitive fluorescent ratiometric pH probe in a physiological buffer is demonstrated....

  20. 101-SY waste sample speed of sound/rheology testing for sonic probe program

    International Nuclear Information System (INIS)

    Cannon, N.S.

    1994-01-01

    One problem faced in the clean-up operation at Hanford is that a number of radioactive waste storage tanks are experiencing a periodic buildup and release of potentially explosive gases. The best known example is Tank 241-SY-101 (commonly referred to as 101-SY) in which hydrogen gas periodically built up within the waste to the point that increased buoyancy caused a roll-over event, in which the gas was suddenly released in potentially explosive concentrations (if an ignition source were present). The sonic probe concept is to generate acoustic vibrations in the 101-SY tank waste at nominally 100 Hz, with sufficient amplitude to cause the controlled release of hydrogen bubbles trapped in the waste. The sonic probe may provide a potentially cost-effective alternative to large mixer pumps now used for hydrogen mitigation purposes. Two important parameters needed to determine sonic probe effectiveness and design are the speed of sound and yield stress of the tank waste. Tests to determine these parameters in a 240 ml sample of 101-SY waste (obtained near the tank bottom) were performed, and the results are reported

  1. Preparation and quality test of superparamagnetic iron oxide labeled antisense oligodeoxynucleotide probe: a preliminary study.

    Science.gov (United States)

    Wen, Ming; Li, Bibo; Ouyang, Yu; Luo, Yi; Li, Shaolin

    2009-06-01

    Molecular imaging of tumor antisense gene techniques have been applied to the study of magnetic resonance (MR) gene imaging associated with malignant tumors. In this study, we designed, synthesized, and tested a novel molecular probe, in which the antisense oligodeoxynucleotide (ASODN) was labeled with superparamagnetic iron oxide (SPIO), and its efficiency was examined by in vitro MR imaging after SK-Br-3 mammary carcinoma cell lines (oncocytes) transfection. The SPIO-labeled ASODN probe was prepared through SPIO conjugated to ASODN using a chemical cross linking method. Its morphology and size were detected by atomic force microscope, size distribution were detected by laser granulometer, the conjugating rate and biological activity were determined by high performance liquid chromatography, and the stability was determined by polyacrylamide gel electrophoresis. After that, the probes were transfected into the SK-Br-3 oncocytes, cellular iron uptake was analyzed qualitatively at light and electron microscopy and was quantified at atomic absorption spectrometry, and the signal change of the transfected cells was observed and measured using MR imaging. The morphology of the SPIO-labeled ASODN probe was mostly spherical with well-distributed scattering, and the diameters were between 25 and 40 nm (95%) by atomic force microscope and laser granulometer, the conjugating rate of the probe was 99%. Moreover, this probe kept its activity under physiological conditions and could conjugate with antisense oligodeoxynucleotide. In addition, light microscopy revealed an intracellular uptake of iron oxides in the cytosol and electron microscopic studies revealed a lysosomal deposition of iron oxides in the transfected SK-Br-3 oncocytes by antisense probes, some of them gathered stacks, and the iron content of the group of transfected SK-Br-3 oncocytes by antisense probe is significantly higher (18.37 +/- 0.42 pg) than other contrast groups, the MR imaging showed that

  2. Probing the onset of structural instabilities as a tool for detection of staling of dairy milk: A permittivity and conductivity study

    Science.gov (United States)

    Madhurima, V.; Harindran, Aswini

    2018-05-01

    Dairy milk is a worldwide drink and a versatile raw material for food industries too. The major issue regarding dairy milk is their contamination by micro-organisms and subsequent spoiling. Pasteurization and sealed packing are used to minimize this contamination. The presence of pathogenic micro-organisms like psychrotrophs, reduces the pH of fresh milk by fermenting the lactose into lactic acid leading to the spoiling of milk. While there are various tests to check the spoilage of milk, there is no unique test to detect the onset of the complex dynamics of spoilage. There have been some studies on the dielectric properties of dairy milk but the primary method of identification of freshness of milk is through the measurement of pH. In this study, broadband dielectric spectroscopy is used as a tool to probe the spoiling of milk and that provides the information about the structural changes of milk during spoilage. The gamma dispersion explains the influence of free water content which is found to be a sensitive tool to probe the onset of milk spoilage process. The observations here are further backed by studies on the particle size and zeta potential.

  3. Continuous pH monitoring in a perfused bioreactor system using an optical pH sensor

    Science.gov (United States)

    Jeevarajan, Antony S.; Vani, Sundeep; Taylor, Thomas D.; Anderson, Melody M.

    2002-01-01

    Monitoring and regulating the pH of the solution in a bioprocess is one of the key steps in the success of bioreactor operation. An in-line optical pH sensor, based on the optical absorption properties of phenol red present in the medium, was developed and tested in this work for use in NASA space bioreactors based on a rotating wall-perfused vessel system supporting a baby hamster kidney (BHK-21) cell culture. The sensor was tested over three 30-day and one 124-day cell runs. The pH sensor initially was calibrated and then used during the entire cell culture interval. The pH reported by the sensor was compared to that measured by a fiber optically coupled Shimadzu spectrophotometer and a blood gas analyzer. The maximum standard error of prediction for all the four cell runs for development pH sensor against BGA was +/-0.06 pH unit and for the fiber optically coupled Shimadzu spectrophotometer against the blood gas analyzer was +/-0.05 pH unit. The pH sensor system performed well without need of recalibration for 124 days. Copyright 2002 Wiley Periodicals, Inc.

  4. Combinatorial Dansyl Library and its Applications to pH-Responsive Probes.

    Science.gov (United States)

    Hong, Seong Cheol; Murale, Dhiraj P; Lee, Jun-Seok

    2016-01-01

    Herein, we report the first 48-membered, dansyl-based, combinatorial fluorescent library. From the electronic and structural properties of the probes, we analyzed their optical properties and chemical yields, with an average of 49 %. The molecules were examined for their pH responses, and DS-2 and DS-45 showed blue-shifts, whereas DS-7 and DS-40 showed red-shifts in wavelength with increasing pH. Finally, cell permeability was investigated by treating SNU-2292 cells. Our results demonstrate the potential application of this library in biosensors, bio-imaging and pH indicators.

  5. Fluorescent probe based on heteroatom containing styrylcyanine: pH-sensitive properties and bioimaging in vivo

    International Nuclear Information System (INIS)

    Yang, Xiaodong; Gao, Ya; Huang, Zhibing; Chen, Xiaohui; Ke, Zhiyong; Zhao, Peiliang; Yan, Yichen; Liu, Ruiyuan; Qu, Jinqing

    2015-01-01

    A novel fluorescent probe based on heteroatom containing styrylcyanine is synthesized. The fluorescence of probe is bright green in basic and neutral media but dark orange in strong acidic environments, which could be reversibly switched. Such behavior enables it to work as a fluorescent pH sensor in the solution state and a chemosensor for detecting acidic and basic volatile organic compounds. Analyses by NMR spectroscopy confirm that the protonation or deprotonation of pyridinyl moiety is responsible for the sensing process. In addition, the fluorescent microscopic images of probe in live cells and zebrafish are achieved successfully, suggesting that the probe has good cell membrane permeability and low cytotoxicity. - Graphical abstract: A novel styrylcyanine-based fluorescent pH probe was designed and synthesized, the fluorescence of which is bright green in basic and neutral media but dark orange in strong acidic environments. Such behavior enables it to work as a fluorescent pH sensor in solution states, and a chemosensor for detecting volatile organic compounds with high acidity and basicity in solid state. In addition, it can be used for fluorescent imaging in living cell and living organism. - Highlights: • Bright green fluorescence was observed in basic and neutral media. • Dark orange fluorescence was found in strong acidic environments. • Volatile organic compounds with high acidity and basicity could be detected. • Bioimaging in living cell and living organism was achieved successfully

  6. Computer modelling of eddy current probes

    International Nuclear Information System (INIS)

    Sullivan, S.P.

    1992-01-01

    Computer programs have been developed for modelling impedance and transmit-receive eddy current probes in two-dimensional axis-symmetric configurations. These programs, which are based on analytic equations, simulate bobbin probes in infinitely long tubes and surface probes on plates. They calculate probe signal due to uniform variations in conductor thickness, resistivity and permeability. These signals depend on probe design and frequency. A finite element numerical program has been procured to calculate magnetic permeability in non-linear ferromagnetic materials. Permeability values from these calculations can be incorporated into the above analytic programs to predict signals from eddy current probes with permanent magnets in ferromagnetic tubes. These programs were used to test various probe designs for new testing applications. Measurements of magnetic permeability in magnetically biased ferromagnetic materials have been performed by superimposing experimental signals, from special laboratory ET probes, on impedance plane diagrams calculated using these programs. (author). 3 refs., 2 figs

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

    International Nuclear Information System (INIS)

    Alonso, M. C.; Garcia Calvo, J. L.; Walker, C.

    2012-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-08-15

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

  9. Ultramild protein-mediated click chemistry creates efficient oligonucleotide probes for targeting and detecting nucleic acids

    DEFF Research Database (Denmark)

    Nåbo, Lina J.; Madsen, Charlotte S.; Jensen, Knud J.

    2015-01-01

    Functionalized synthetic oligonucleotides are finding growing applications in research, clinical studies, and therapy. However, it is not easy to prepare them in a biocompatible and highly efficient manner. We report a new strategy to synthesize oligonucleotides with promising nucleic acid...... targeting and detection properties. We focus in particular on the pH sensitivity of these new probes and their high target specificity. For the first time, human copper(I)-binding chaperon Cox17 was applied to effectively catalyze click labeling of oligonucleotides. This was performed under ultramild...... conditions with fluorophore, peptide, and carbohydrate azide derivatives. In thermal denaturation studies, the modified probes showed specific binding to complementary DNA and RNA targets. Finally, we demonstrated the pH sensitivity of the new rhodamine-based fluorescent probes in vitro and rationalize our...

  10. A Genetically Encoded pH Sensor for Tracking Surface Proteins through Endocytosis**

    OpenAIRE

    Grover, Anmol; Schmidt, Brigitte F.; Salter, Russell D.; Watkins, Simon C.; Waggoner, Alan S.; Bruchez, Marcel P.

    2012-01-01

    We have combined our fluorogen activating peptide[1] with a new tandem dye molecule to develop a biosensor that labels a cell-surface protein and displays an easily detectable pH dependent emission color change by efficient intramolecular Förster resonant energy transfer. This probe has demonstrated pH variations in β2-adrenergic receptor trafficking and revealed a process of surface to endosome inter-cellular transfer in dendritic cells with potential significance in antigen transfer.

  11. Diurnal variation of intraoral pH and temperature.

    Science.gov (United States)

    Choi, Jung Eun; Lyons, Karl M; Kieser, Jules A; Waddell, Neil J

    2017-01-01

    The aim of this study was to measure continuously the intraoral pH and temperature of healthy individuals to investigate their diurnal variations. Seventeen participants (mean age, 31±9 years) wore a custom-made intraoral appliance fitted with a pH probe and thermocouple for two sets of 24 h, while carrying out normal daily activities including sleep. The continuous changes in intraoral pH and temperature were captured using a sensor placed on the palatal aspect of the upper central incisors. The collected data were categorised into different status (awake and sleep) and periods (morning, afternoon, evening and night). Both quantitative and qualitative analyses were conducted. The intraoral pH change was found to show a distinctive daily rhythm, showing a 12-h interval between maximum (7.73) and minimum (6.6) pH values. The maximum and minimum values were found to repeat after 24 h. The mean pH over 48 h (two sets of 24 h) was found to be 7.27 (±0.74). There was significant difference found in pH when subjects were awake and asleep and different periods during the day ( P pH. There was a significant difference found in temperature depending on the time of the day, except between morning and afternoon ( P =0.78). Our results showed that there is a distinctive daily, circadian-like pattern in intraoral pH variation over a 24-h period, which has been considered as one of the risk factors in sleep-related dental diseases.

  12. Designs of Langmuir probes for W7-X

    International Nuclear Information System (INIS)

    Laube, Ralph; Laux, Michael; Ye, Min You; Greuner, Henri; Lindig, Stefan

    2011-01-01

    Several designs of Langmuir probes for the stellarator Wendelstein 7-X (W7-X) are described. Different types of probes are proposed for the different divertors to be used during different operational phases of W7-X. Comb-like arrays of stiff probes, arrays of flexible probes, and fixed inlay probes are reviewed. For the initial phase of W7-X it was decided to install arrays of fixed inlay probes. Two mockups were manufactured and one of them was tested with success in the high heat flux test facility GLADIS. For long-pulse operation of W7-X different conceptual designs are proposed and are still developed further. This paper summarizes the different design constrains for the Langmuir probes in the different divertor surroundings, describes the design of the array of inlay probes for the initial phase and the result of the GLADIS test, and gives a preview of the conceptual designs of probes for the long-pulse operational phase of W7-X.

  13. Microneedle pH Sensor: Direct, Label-Free, Real-Time Detection of Cerebrospinal Fluid and Bladder pH.

    Science.gov (United States)

    Mani, Ganesh Kumar; Miyakoda, Kousei; Saito, Asuka; Yasoda, Yutaka; Kajiwara, Kagemasa; Kimura, Minoru; Tsuchiya, Kazuyoshi

    2017-07-05

    Acid-base homeostasis (body pH) inside the body is precisely controlled by the kidneys and lungs and buffer systems, such that even a minor pH change could severely affect many organs. Blood and urine pH tests are common in day-to-day clinical trials and require little effort for diagnosis. There is always a great demand for in vivo testing to understand more about body metabolism and to provide effective diagnosis and therapy. In this article, we report the simple fabrication of microneedle-based direct, label-free, and real-time pH sensors. The reference and working electrodes were Ag/AgCl thick films and ZnO thin films on tungsten (W) microneedles, respectively. The morphological and structural characteristics of microneedles were carefully investigated through various analytical methods. The developed sensor exhibited a Nernstian response of -46 mV/pH. Different conditions were used to test the sensor to confirm their accuracy and stability, such as various buffer solutions, with respect to time, and we compared the reading with commercial pH electrodes. Besides that, the fabricated microneedle sensor ability is proven by in vivo testing in mouse cerebrospinal fluid (CSF) and bladders. The pH sensor procedure reported here is totally reversible, and results were reproducible after several rounds of testing.

  14. Millimeter/submillimeter Spectroscopy of PH2CN ({\\tilde{X}} 1A') and CH3PH2 ({\\tilde{X}} 1A'): Probing the Complexity of Interstellar Phosphorus Chemistry

    Science.gov (United States)

    Halfen, D. T.; Clouthier, D. J.; Ziurys, L. M.

    2014-11-01

    Millimeter/submillimeter spectra of PH2CN ({\\tilde{X}} 1A') and CH3PH2 ({\\tilde{X}} 1A') have been recorded for the first time using direct absorption techniques. This work extends previous measurements of both molecules beyond the 10-50 GHz range. Both species were created in the presence of an AC discharge by the reaction of phosphorus vapor and either cyanogen and hydrogen (PH2CN) or methane (CH3PH2). Twelve rotational transitions of PH2CN were recorded over the region 305-422 GHz for asymmetry components Ka = 0 through 8. For CH3PH2, eight rotational transitions were measured from 210-470 GHz with Ka = 0 through 16; these spectra exhibited greater complexity due to the presence of internal rotation, which splits the Ka = 1, 2, and 3 asymmetry components into A and E states. Combined analyses of the millimeter/submillimeter and previous microwave data were performed for both molecules. For PH2CN, the spectra were fit with a Watson S-reduced asymmetric top Hamiltonian, resulting in more accurate rotational and centrifugal distortion constants. In the case of CH3PH2, an asymmetric top internal-rotation Hamiltonian was employed in the analysis, significantly improving the rotational and torsional parameters over previous microwave estimates. Searches for both molecules were subsequently conducted toward Sgr B2(N), using the 12 m telescope of the Arizona Radio Observatory (ARO). Neither species was identified, with abundance upper limits, relative to H2, of f (PH2CN/H2) PH2/H2) 2 and >200, respectively.

  15. A protein-dye hybrid system as a narrow range tunable intracellular pH sensor.

    Science.gov (United States)

    Anees, Palapuravan; Sudheesh, Karivachery V; Jayamurthy, Purushothaman; Chandrika, Arunkumar R; Omkumar, Ramakrishnapillai V; Ajayaghosh, Ayyappanpillai

    2016-11-18

    Accurate monitoring of pH variations inside cells is important for the early diagnosis of diseases such as cancer. Even though a variety of different pH sensors are available, construction of a custom-made sensor array for measuring minute variations in a narrow biological pH window, using easily available constituents, is a challenge. Here we report two-component hybrid sensors derived from a protein and organic dye nanoparticles whose sensitivity range can be tuned by choosing different ratios of the components, to monitor the minute pH variations in a given system. The dye interacts noncovalently with the protein at lower pH and covalently at higher pH, triggering two distinguishable fluorescent signals at 700 and 480 nm, respectively. The pH sensitivity region of the probe can be tuned for every unit of the pH window resulting in custom-made pH sensors. These narrow range tunable pH sensors have been used to monitor pH variations in HeLa cells using the fluorescence imaging technique.

  16. Optimization of urinary dipstick pH: Are multiple dipstick pH readings reliably comparable to commercial 24-hour urinary pH?

    Science.gov (United States)

    Abbott, Joel E; Miller, Daniel L; Shi, William; Wenzler, David; Elkhoury, Fuad F; Patel, Nishant D; Sur, Roger L

    2017-09-01

    Accurate measurement of pH is necessary to guide medical management of nephrolithiasis. Urinary dipsticks offer a convenient method to measure pH, but prior studies have only assessed the accuracy of a single, spot dipstick. Given the known diurnal variation in pH, a single dipstick pH is unlikely to reflect the average daily urinary pH. Our goal was to determine whether multiple dipstick pH readings would be reliably comparable to pH from a 24-hour urine analysis. Kidney stone patients undergoing a 24-hour urine collection were enrolled and took images of dipsticks from their first 3 voids concurrently with the 24-hour collection. Images were sent to and read by a study investigator. The individual and mean pH from the dipsticks were compared to the 24-hour urine pH and considered to be accurate if the dipstick readings were within 0.5 of the 24-hour urine pH. The Bland-Altman test of agreement was used to further compare dipstick pH relative to 24-hour urine pH. Fifty-nine percent of patients had mean urinary pH values within 0.5 pH units of their 24-hour urine pH. Bland-Altman analysis showed a mean difference between dipstick pH and 24-hour urine pH of -0.22, with an upper limit of agreement of 1.02 (95% confidence interval [CI], 0.45-1.59) and a lower limit of agreement of -1.47 (95% CI, -2.04 to -0.90). We concluded that urinary dipstick based pH measurement lacks the precision required to guide medical management of nephrolithiasis and physicians should use 24-hour urine analysis to base their metabolic therapy.

  17. Evaluation of the Gen-Probe DNA probe for the detection of legionellae in culture

    International Nuclear Information System (INIS)

    Edelstein, P.H.

    1986-01-01

    A commercial DNA probe kit designed to detect rRNA from legionellae was evaluated for its ability to correctly discriminate between legionellae and non-legionellae taken from culture plates. The probe kit, made by the Gen-Probe Corp. (San Diego, Calif.), was radiolabeled with 125 I, and probe bacterial RNA hybridization, detected in a simple one-tube system hybridization assay, was quantitated with a gamma counter. A total of 156 Legionella sp. strains were tested, of which 125 were Legionella pneumophila and the remainder were strains from 21 other Legionella spp. A total of 106 gram-negative non-legionellae, isolated from human respiratory tract (81%) and other body site (19%) specimens, were also tested; 14 genera and 28 species were represented. The probe easily distinguished all of the legionellae from the non-legionellae. The average legionellae/non-legionellae hybridization ratio was 42:1, and the lowest ratio was 2:1; a minor modification in the procedure increased the lowest ratio to 5:1. In addition to correctly identifying all Legionella species, the probe was able to separate some of the various species of Legionella. L. pneumophila strains hybridized more completely to the probe than did the other Legionella spp.; L. wadsworthii and L. oakridgensis hybridized only about 25% of the probe relative to L. pneumophila. Some strains of phenotypically identified L. pneumophila had much lower hybridization to the probe than other members of the species and may represent a new Legionella species. The simplicity of the technique and specificity of the probe make it a good candidate for confirming the identity of legionellae in culture

  18. Characteristics Testing of the ECT Bobbin Probe for S/G Tube Inspection

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Min Woo; Lee, Hee Jong; Cho, Chan Hee; Yoo, Hyun Joo [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

    2010-05-15

    The bobbin probe technique is basically one of the important ECT methods for the steam generator tube integrity assessment that is practiced during each plant outage. The bobbin probe also is the essential component which consists of the whole ECT examination system, and provides a decisive data for the evaluation of tube integrity in compliance with acceptance criteria described in specific procedures. The selection of probe is especially important because the quality of acquired ECT data is determined by the probe design characteristics, such as geometry and operation frequency, and has an important effect on examination results. The Electric Power Research Institute (EPRI) has recently defined the procedures for the qualification of eddy current hardware and technique. These procedures provide two basic methods for qualification. Flawed tube removed from operation, or artificial flaw is required for the original qualification of technique combined with related flaw mechanism. In case where the original qualification has been completed, the concept of equivalency may be used to extend the original qualification to similar probe designs. The qualified acquisition technique may be modified to substitute or replace instruments or probes without re-qualification provided that the range of essential variables defined in the examination technique specification sheet are met. In this case, both the original and replaced instrument or probe shall be characterized utilizing EPRI Guideline supplement 'H1'. This study is the result of the comparative performance evaluation of bobbin coil eddy current probes manufactured by KEPRI and a foreign manufacturer. As a result of this study, although there were minor differences between the two probe types, it was evaluated that the two probes were almost identical in the significant performance characteristics described in the EPRI guideline

  19. A lysosome-locating and acidic pH-activatable fluorescent probe for visualizing endogenous H2O2 in lysosomes.

    Science.gov (United States)

    Liu, Jun; Zhou, Shunqing; Ren, Jing; Wu, Chuanliu; Zhao, Yibing

    2017-11-20

    There is increasing evidence indicating that lysosomal H 2 O 2 is closely related to autophagy and apoptotic pathways under both physiological and pathological conditions. Therefore, fluorescent probes that can be exploited to visualize H 2 O 2 in lysosomes are potential tools for exploring diverse roles of H 2 O 2 in cells. However, functional exploration of lysosomal H 2 O 2 is limited by the lack of fluorescent probes capable of compatibly sensing H 2 O 2 under weak acidic conditions (pH = 4.5) of lysosomes. Lower spatial resolution of the fluorescent visualization of lysosomal H 2 O 2 might be caused by the interference of signals from cytosolic and mitochondrial H 2 O 2 , as well as the non-specific distribution of the probes in cells. In this work, we developed a lysosome-locating and acidic-pH-activatable fluorescent probe for the detection and visualization of H 2 O 2 in lysosomes, which consists of a H 2 O 2 -responsive boronate unit, a lysosome-locating morpholine group, and a pH-activatable benzorhodol fluorophore. The response of the fluorescent probe to H 2 O 2 is significantly more pronounced under acidic pH conditions than that under neutral pH conditions. Notably, the present probe enables the fluorescence sensing of endogenous lysosomal H 2 O 2 in living cells without external stimulations, with signal interference from the cytoplasm and other intracellular organelles being negligible.

  20. Human MLPA Probe Design (H-MAPD: a probe design tool for both electrophoresis-based and bead-coupled human multiplex ligation-dependent probe amplification assays

    Directory of Open Access Journals (Sweden)

    Hatchwell Eli

    2008-09-01

    Full Text Available Abstract Background Multiplex ligation-dependent probe amplification (MLPA is an efficient and reliable technique for gene dosage analysis. Currently MLPA can be conducted on two platforms: traditional electrophoresis-based, and FlexMAP bead-coupled. Since its introduction in 2002, MLPA has been rapidly adopted in both clinical and research situations. However, MLPA probe design is a time consuming process requiring many steps that address multiple criteria. There exist only one or two commercial software packages for traditional electrophoresis-based MLPA probe design. To our knowledge, no software is yet available that performs bead-coupled MLPA probe design. Results We have developed H-MAPD, a web-based tool that automates the generation and selection of probes for human genomic MLPA. The software performs physical-chemical property tests using UNAFold software, and uniqueness tests using the UCSC genome browser. H-MAPD supports both traditional electrophoresis-based assays, as well as FlexMAP bead-coupled MLPA. Conclusion H-MAPD greatly reduces the efforts for human genomic MLPA probe design. The software is written in Perl-CGI, hosted on a Linux server, and is freely available to non-commercial users.

  1. Imaging optical probe for pressurized steam-water environment

    International Nuclear Information System (INIS)

    Donaldson, M.R.; Pulfrey, R.E.

    1979-01-01

    An air-cooled imaging optical probe, with an outside diameter of 25.4 mm, has been developed to provide high resolution viewing of flow regimes in a steam-water environment at 343 0 C and 15.2 MPa. The design study considered a 3-m length probe. A 0.3-m length probe prototype was fabricated and tested. The optical probe consists of a 3.5-mm diameter optics train surrounded by two coaxial coolant flow channels and two coaxial insulating dead air spaces. With air flowing through the probe at 5.7 g/s, thermal analysis shows that no part of the optics train will exceed 93 0 C when a 3-m length probe is immersed in a 343 0 C environment. Computer stress analysis plus actual tests show that the probe can operate successfully with conservative safety factors. The imaging optical probe was tested five times in the design environment at the semiscale facility at the INEL. Two-phase flow regimes in the high temperature, high pressure, steam-water blowdown and reflood experiments were recorded on video tape for the first time with the imaging optical probe

  2. Hydrazine functionalized probes for chromogenic and fluorescent ratiometric sensing of pH and F-: experimental and DFT studies.

    Science.gov (United States)

    Roy Chowdhury, Additi; Mondal, Amita; Roy, Biswajit Gopal; K, Jagadeesh C Bose; Mukhopadhyay, Sudit; Banerjee, Priyabrata

    2017-11-08

    Two novel hydrazine based sensors, BPPIH (N 1 ,N 3 -bis(perfluorophenyl)isophthalohydrazide) and BPBIH (N 1' ,N 3' -bis(perfluorobenzylidene)isophthalohydrazide), are presented here. BPPIH is found to be a highly sensitive pH sensor in the pH range 5.0 to 10.0 in a DMSO-water solvent mixture with a pK a value of 9.22. Interesting optical responses have been observed for BPPIH in the above mentioned pH range. BPBIH on the other hand turns out to be a less effective pH sensor in the above mentioned pH range. The increase in fluorescence intensity at a lower pH for BPPIH was explained by using density functional theory. The ability of BPPIH to monitor the pH changes inside cancer cells is a useful application of the sensor as a functional material. In addition fluoride (F - ) selectivity studies of these two chemosensors have been performed and show that between them, BPBIH shows greater selectivity towards F - . The interaction energy calculated from the DFT-D3 supports the experimental findings. The pH sensor (BPPIH) can be further interfaced with suitable circuitry interfaced with desired programming for ease of access and enhancement of practical applications.

  3. Electrochemical probing of high-level radioactive waste tanks containing washed sludge and precipitates

    International Nuclear Information System (INIS)

    Bickford, D.F.; Congdon, J.W.; Oblath, S.B.

    1986-12-01

    At the US Department of Energy's Savannah River Plant, corrosion of carbon steel storage tanks containing alkaline, high-level radioactive waste is controlled by specification of limits on waste composition and temperature. Processes for the preparation of waste for final disposal will result in waste with low corrosion inhibitor concentrations and, in some cases, high aromatic organic concentrations, neither of which are characteristic of previous operations. Laboratory tests, conducted to determine minimum corrosion inhibitor levels indicated pitting of carbon steel near the waterline for proposed storage conditions. In situ electrochemical measurements of full-scale radioactive process demonstrations have been conducted to assess the validity of laboratory tests. Probes included pH, Eh (potential relative to a standard hydrogen electrode), tank potential, and alloy coupons. In situ results are compared to those of the laboratory tests, with particular regard given to simulated solution composition. Transition metal hydroxide sludge contains strong passivating species for carbon steel. Washed precipitate contains organic species that lower solution pH and tend to reduce passivating films, requiring higher inhibitor concentrations than the 0.01 molar nitrite required for reactor fuel reprocessing wastes. Periodic agitation, to keep the organic phase suspended, or cathodic protection are possible alternatives to higher nitrite inhibitor concentrations

  4. Abilities of Oropharyngeal pH Tests and Salivary Pepsin Analysis to Discriminate Between Asymptomatic Volunteers and Subjects With Symptoms of Laryngeal Irritation.

    Science.gov (United States)

    Yadlapati, Rena; Adkins, Christopher; Jaiyeola, Diana-Marie; Lidder, Alcina K; Gawron, Andrew J; Tan, Bruce K; Shabeeb, Nadine; Price, Caroline P E; Agrawal, Neelima; Ellenbogen, Michael; Smith, Stephanie S; Bove, Michiel; Pandolfino, John E

    2016-04-01

    It has been a challenge to confirm the association between laryngeal symptoms and physiological reflux disease. We examined the ability of oropharyngeal pH tests (with the Restech Dx-pH system) and salivary pepsin tests (with Peptest) to discriminate between asymptomatic volunteers (controls) and subjects with a combination of laryngeal and reflux symptoms (laryngeal ± reflux). We performed a physician-blinded prospective cohort study of 59 subjects at a single academic institution. Adult volunteers were recruited and separated into 3 groups on the basis of GerdQ and Reflux Symptom Index scores: controls (n = 20), laryngeal symptoms (n = 20), or laryngeal + reflux symptoms (n = 19). Subjects underwent laryngoscopy and oropharyngeal pH tests and submitted saliva samples for analysis of pepsin concentration. Primary outcomes included abnormal acid exposure and composite (RYAN) score for oropharyngeal pH tests and abnormal mean salivary pepsin concentration that was based on normative data. Complete oropharyngeal pH data were available from 53 subjects and complete salivary pepsin data from 35 subjects. We did not observe any significant differences between groups in percent of time spent below pH 4.0, 5.0, 5.5, 6.0, or RYAN scores or percent of subjects with positive results from tests for salivary pepsin (53% vs 40% vs 75%; P = .50, respectively). The laryngeal + reflux group had a significantly higher estimated mean concentration of salivary pepsin (117.9 ± 147.4 ng/mL) than the control group (32.4 ± 41.9 ng/mL) or laryngeal symptom group (7.5 ± 11.2 ng/mL) (P = .01 and P = .04, respectively). By using current normative thresholds, oropharyngeal pH testing and salivary pepsin analysis are not able to distinguish between healthy volunteers and subjects with a combination of laryngeal and reflux symptoms. Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.

  5. EPR spin probe and spin label studies of some low molecular and polymer micelles

    Science.gov (United States)

    Wasserman, A. M.; Kasaikin, V. A.; Timofeev, V. P.

    1998-12-01

    The rotational mobility of spin probes of different shape and size in low molecular and polymer micelles has been studied. Several probes having nitroxide fragment localized either in the vicinity of micelle interface or in the hydrocarbon core have been used. Upon increasing the number of carbon atoms in hydrocarbon chain of detergent from 7 to 13 (sodium alkyl sulfate micelles) or from 12 to 16 (alkyltrimethylammonium bromide micelles) the rotational mobility of spin probes is decreased by the factor 1.5-2.0. The spin probe rotational mobility in polymer micelles (the complexes of alkyltrimethylammonium bromides and polymethacrylic or polyacrylic acids) is less than mobility in free micelles of the same surfactants. The study of EPR-spectra of spin labeled polymethacrylic acid (PMA) indicated that formation of water soluble complexes of polymer and alkyltrimethylammonium bromides in alkaline solutions (pH 9) does not affect the polymer segmental mobility. On the other hand, the polymer complexes formation in slightly acidic water solution (pH 6) breaks down the compact PMA conformation, thus increasing the polymer segmental mobility. Possible structures of polymer micelles are discussed.

  6. Mode of corrosion monitoring by electrochemical measurements in alkaline water solutions at 310 degC using a new type of industrial probes with high radiation stability

    International Nuclear Information System (INIS)

    Beran, J.

    1977-01-01

    Application of the linear polarization method to Zr-alloys and low-alloy steel was successfully verified by autoclave tests in alkaline water solutions, pH=10.3 max. The new type of industrial probes for electrochemical measurements worked 5500 hours at temperatures within 250 and 310 degC. Contrary to usual practice, the corrosion rate was evaluated applying the criterion T/Rsub(p) instead of criterion 1/Rsub(p). A single calibration curve T/Rsub(p) versus corrosion rate, which is independent of test temperature, was introduced in this way. The probes, developed by SKODA-Works, Nuclear Power Construction Division for electrochemical measurements in nuclear reactor environment, do not contain organic compounds (for sealing, insulation etc.) in order to prevent radiation damage. (author)

  7. development and testing of multi-level temperature probe

    African Journals Online (AJOL)

    user

    2017-01-01

    Jan 1, 2017 ... resistant, adjustable multi-sensor temperature probe for underwater temperature measurement. It consists of three ... This results in a longitudinal change in water temperature as the .... Source: The Engineering Toolbox ...

  8. Single Nanowire Probe for Single Cell Endoscopy and Sensing

    Science.gov (United States)

    Yan, Ruoxue

    adaptable to average bio-lab environment. These probes are mechanically robust and flexible and can withstand repeated bending and deformation without significant deterioration in optical performance, which offers an ideal instrumental platform for out subsequent effort of using these nanoprobes in chemical sensing as well as single cell endoscopy and spot delivery. Parameters affecting the coupling efficiency and output power of the nanoprobe were studied and chemical etched of single mode fiber with small cone angle was established to be optimized for highly effective optical nanoprobes. The versatility of the nanoprobe design was first tested by transforming the nanowire probe into a pH sensor with near-field photopolymerization of a copolymer containing pH sensitive dye on the tip of the nanowire. The pH-sensitive nanoprobe was able to report the pH difference in micro-droplets containing buffer solution with the excitation of light waveguided on the nanoprobe with internal calibration, fast response time and good photostability and reversibility. Such nanoprobe sensors are ideal for high definition spatial and temporal sensing of concentration profile, especially for the kinetic processes in single cell studies for which chemical probes of minute sizes and fast response are desired. The nanoprobe was then applied into spot cargo delivery and in-situ single cell endoscopy. It was demonstrated that nanowire-based optical probe can deliver payloads into the cell with a high spatiotemporal precision, guide and confine visible light into intracellular compartments selectively and detect optical signals from the subcellular regions with high spatial resolution. The nanoprobe was proven to be biocompatible and non-invasive. The effective optical coupling between the fiber optics and the nanowire enables highly localized excitation and detection, limiting the probe volume to the close proximity of the nanowire. None the less, this versatile technique does not rely on any

  9. Development and characterization of a voltammetric carbon-fiber microelectrode pH sensor.

    Science.gov (United States)

    Makos, Monique A; Omiatek, Donna M; Ewing, Andrew G; Heien, Michael L

    2010-06-15

    This work describes the development and characterization of a modified carbon-fiber microelectrode sensor capable of measuring real-time physiological pH changes in biological microenvironments. The reagentless sensor was fabricated under ambient conditions from voltammetric reduction of the diazonium salt Fast Blue RR onto a carbon-fiber surface in aprotic media. Fast-scan cyclic voltammetry was used to probe redox activity of the p-quinone moiety of the surface-bound molecule as a function of pH. In vitro calibration of the sensor in solutions ranging from pH 6.5 to 8.0 resulted in a pH-dependent anodic peak potential response. Flow-injection analysis was used to characterize the modified microelectrode, revealing sensitivity to acidic and basic changes discernible to 0.005 pH units. Furthermore, the modified electrode was used to measure dynamic in vivo pH changes evoked during neurotransmitter release in the central nervous system of the microanalytical model organism Drosophila melanogaster.

  10. Corrosion of zirconium alloys in alternating pH environment

    International Nuclear Information System (INIS)

    Mayer, P.; Manolescu, A.V.

    1985-01-01

    Behaviour of two commercial alloys, Zircaloy-2 and zirconium-2.5 wt% niobium were investigated in an environment of alternating pH. Corrosion advancement and scale morphology of coupons exposed to aqueous solution of LiOH (pH 10.2 and 14) were followed as a function of temperature (300-360 degreesC) and time (up to 165 days). The test sequence consisted of short term exposure to high pH and re-exposure to low pH solutions for extended period of time followed by a short term test in high pH. The results of these tests and detailed post-corrosion analysis indicate a fundamental difference between the corrosion behaviour of these two materials. Both alloys corrode fast in high pH environments, but only zirconium-2.5 wt% niobium continues to form detectable new oxide in low pH solution

  11. Completed Gravity Probe B Undergoes Thermal Vacuum Testing

    Science.gov (United States)

    2000-01-01

    The Gravity Probe B (GP-B) is the relativity experiment developed at Stanford University to test two extraordinary predictions of Albert Einstein's general theory of relativity. The experiment will measure, very precisely, the expected tiny changes in the direction of the spin axes of four gyroscopes contained in an Earth-orbiting satellite at a 400-mile altitude. So free are the gyroscopes from disturbance that they will provide an almost perfect space-time reference system. They will measure how space and time are very slightly warped by the presence of the Earth, and, more profoundly, how the Earth's rotation very slightly drags space-time around with it. These effects, though small for the Earth, have far-reaching implications for the nature of matter and the structure of the Universe. In this photograph, the completed space vehicle is undergoing thermal vacuum environment testing. GP-B is among the most thoroughly researched programs ever undertaken by NASA. This is the story of a scientific quest in which physicists and engineers have collaborated closely over many years. Inspired by their quest, they have invented a whole range of technologies that are already enlivening other branches of science and engineering. Launched April 20, 2004 , the GP-B program was managed for NASA by the Marshall Space Flight Center. Development of the GP-B is the responsibility of Stanford University along with major subcontractor Lockheed Martin Corporation. (Image credit to Russ Underwood, Lockheed Martin Corporation.)

  12. Esophageal motility and 24-h pH profiles of patients with heterotopic gastric mucosa in the cervical esophagus.

    Science.gov (United States)

    Korkut, Esin; Bektaş, Mehmet; Alkan, Murat; Ustün, Yusuf; Meco, Cem; Ozden, Ali; Soykan, Irfan

    2010-02-01

    Heterotopic gastric mucosa occurs as a flat island of red mucosa in the proximal third of the esophagus where it gives rise to the cervical inlet patch. The aims of this study were to investigate the esophageal motility pattern and 24-h pH profiles of patients with cervical inlet patch. Thirty patients (16 women, mean age: 44.9 years, range: 23-72) diagnosed as having heterotopic gastric mucosa in the cervical esophagus with upper gastrointestinal symptoms had undergone esophageal motility testing and 24-h pH monitorisation with a double-channel pH probe. Manometric investigation was abnormal in 7 patients (non-specific esophageal motor disorder in 4 patients, esophageal hypomotility in 1 patient, and hypotensive LES in 2 patients). Pathological acid reflux (pHesophagus (percentage of total time of pHmotor dysfunction and "acid independent episodes" from the patches. These abnormalities may be responsible for some of the symptoms of HGM patients. Copyright 2009 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  13. Aspheric surface measurement using capacitive probes

    Science.gov (United States)

    Tao, Xin; Yuan, Daocheng; Li, Shaobo

    2017-02-01

    With the application of aspheres in optical fields, high precision and high efficiency aspheric surface metrology becomes a hot research topic. We describe a novel method of non-contact measurement of aspheric surface with capacitive probe. Taking an eccentric spherical surface as the object of study, the averaging effect of capacitive probe measurement and the influence of tilting the capacitive probe on the measurement results are investigated. By comparing measurement results from simultaneous measurement of the capacitive probe and contact probe of roundness instrument, this paper indicates the feasibility of using capacitive probes to test aspheric surface and proposes the compensation method of measurement error caused by averaging effect and the tilting of the capacitive probe.

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

    Directory of Open Access Journals (Sweden)

    Bruna Rafaela Mendes

    2016-06-01

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

  15. A Small Area In-Situ MEMS Test Structure to Accurately Measure Fracture Strength by Electrostatic Probing

    Energy Technology Data Exchange (ETDEWEB)

    Bitsie, Fernando; Jensen, Brian D.; de Boer, Maarten

    1999-07-15

    We have designed, fabricated, tested and modeled a first generation small area test structure for MEMS fracture studies by electrostatic rather than mechanical probing. Because of its small area, this device has potential applications as a lot monitor of strength or fatigue of the MEMS structural material. By matching deflection versus applied voltage data to a 3-D model of the test structure, we develop high confidence that the local stresses achieved in the gage section are greater than 1 GPa. Brittle failure of the polycrystalline silicon was observed.

  16. Contamination-free sounding rocket Langmuir probe

    Science.gov (United States)

    Amatucci, W. E.; Schuck, P. W.; Walker, D. N.; Kintner, P. M.; Powell, S.; Holback, B.; Leonhardt, D.

    2001-04-01

    A technique for removing surface contaminants from a sounding rocket spherical Langmuir probe is presented. Contamination layers present on probe surfaces can skew the collected data, resulting in the incorrect determination of plasma parameters. Despite following the usual probe cleaning techniques that are used prior to a launch, the probe surface can become coated with layers of adsorbed neutral gas in less than a second when exposed to atmosphere. The laboratory tests reported here show that by heating the probe from the interior using a small halogen lamp, adsorbed neutral particles can be removed from the probe surface, allowing accurate plasma parameter measurements to be made.

  17. Ambulatory oesophageal pH monitoring: a comparison between antimony, ISFET, and glass pH electrodes

    NARCIS (Netherlands)

    Hemmink, Gerrit J. M.; Weusten, Bas L. A. M.; Oors, Jac; Bredenoord, Albert J.; Timmer, Robin; Smout, André J. P. M.

    2010-01-01

    BACKGROUND AND AIM: Ambulatory oesophageal pH-impedance monitoring is a widely used test to evaluate patients with reflux symptoms. Several types of pH electrodes are available: antimony, ion sensitive field effect transistor (ISFET), and glass electrodes. These pH electrodes have not been compared

  18. Analysis of chemical equilibrium of silicon-substituted fluorescein and its application to develop a scaffold for red fluorescent probes.

    Science.gov (United States)

    Hirabayashi, Kazuhisa; Hanaoka, Kenjiro; Takayanagi, Toshio; Toki, Yuko; Egawa, Takahiro; Kamiya, Mako; Komatsu, Toru; Ueno, Tasuku; Terai, Takuya; Yoshida, Kengo; Uchiyama, Masanobu; Nagano, Tetsuo; Urano, Yasuteru

    2015-09-01

    Fluorescein is a representative green fluorophore that has been widely used as a scaffold of practically useful green fluorescent probes. Here, we report synthesis and characterization of a silicon-substituted fluorescein, i.e., 2-COOH TokyoMagenta (2-COOH TM), which is a fluorescein analogue in which the O atom at the 10' position of the xanthene moiety of fluorescein is replaced with a Si atom. This fluorescein analogue forms a spirolactone ring via intramolecular nucleophilic attack of the carboxylic group in a pH-dependent manner. Consequently, 2-COOH TM exhibits characteristic large pH-dependent absorption and fluorescence spectral changes: (1) 2-COOH TM is colorless at acidic pH, whereas fluorescein retains observable absorption and fluorescence even at acidic pH, and the absorption maximum is also shifted; (2) the absorption spectral change occurs above pH 7.0 for 2-COOH TM and below pH 7.0 for fluorescein; (3) 2-COOH TM shows a much sharper pH response than fluorescein because of its pKa inversion, i.e., pKa1 > pKa2. These features are also different from those of a compound without the carboxylic group, 2-Me TokyoMagenta (2-Me TM). Analysis of the chemical equilibrium between pH 3.0 and 11.0 disclosed that 2-COOH TM favors the colorless and nonfluorescent lactone form, compared with fluorescein. Substitution of Cl atoms at the 4' and 5' positions of the xanthene moiety of 2-COOH TM to obtain 2-COOH DCTM shifted the equilibrium so that the new derivative exists predominantly in the strongly fluorescent open form at physiological pH (pH 7.4). To demonstrate the practical utility of 2-COOH DCTM as a novel scaffold for red fluorescent probes, we employed it to develop a probe for β-galactosidase.

  19. Blinded Comparison between an In-Air Reverberation Method and an Electronic Probe Tester in the Detection of Ultrasound Probe Faults.

    Science.gov (United States)

    Dudley, Nicholas J; Woolley, Darren J

    2017-12-01

    The aim of this study was to perform a blinded trial, comparing the results of a visual inspection of the in-air reverberation pattern with the results of an electronic probe tester in detecting ultrasound probe faults. Sixty-two probes were tested. A total of 28 faults were found, 3 only by in-air reverberation assessment and 2 only by the electronic probe tester. The electronic probe tester provided additional information regarding the location of the fault in 74% of the cases in which both methods detected a fault. It is possible to detect the majority of probe faults by visual inspection and in-air reverberation assessment. The latter provides an excellent first-line test, easily performed on a daily basis by equipment users. An electronic probe tester is required if detailed evaluation of faults is necessary. Copyright © 2017 World Federation for Ultrasound in Medicine and Biology. All rights reserved.

  20. Electrochemical probing of high-level radioactive waste tanks containing washed sludge and precipitates

    International Nuclear Information System (INIS)

    Bickford, D.F.; Congdon, J.W.; Oblath, S.B.

    1987-01-01

    At the U.S. Department of Energy's Savannah River Plant, corrosion of carbon steel storage tanks containing alkaline, high-level radioactive waste is controlled by specification of limits on waste composition and temperature. Processes for the preparation of waste for final disposal will result in waste with low corrosion inhibitor concentrations and, in some cases, high aromatic organic concentrations, neither of which are characteristic of previous operations. Laboratory tests, conducted to determine minimum corrosion inhibitor levels indicated pitting of carbon steel near the waterline for proposed storage conditions. In situ electrochemical measurements of full-scale radioactive process demonstrations have been conducted to assess the validity of laboratory tests. Probes included pH, Eh (potential relative to a standard hydrogen electrode), tank potential, and alloy coupons. In situ results are compared to those of the laboratory tests, with particular regard given to simulated solution composition

  1. Salivary pH: A diagnostic biomarker.

    Science.gov (United States)

    Baliga, Sharmila; Muglikar, Sangeeta; Kale, Rahul

    2013-07-01

    Saliva contains a variety of host defense factors. It influences calculus formation and periodontal disease. Different studies have been done to find exact correlation of salivary biomarkers with periodontal disease. With a multitude of biomarkers and complexities in their determination, the salivary pH may be tried to be used as a quick chairside test. The aim of this study was to analyze the pH of saliva and determine its relevance to the severity of periodontal disease. The study population consisted of 300 patients. They were divided into three groups of 100 patients each: Group A had clinically healthy gingiva, Group B who had generalized chronic gingivitis and Group C who had generalized chronic periodontitis. The randomized unstimulated saliva from each patient was collected and pH was tested. Data was analyzed statistically using analysis of variance technique. The salivary pH was more alkaline for patients with generalized chronic gingivitis as compared with the control group (P = 0.001) whereas patients with generalized chronic periodontitis had more acidic pH as compared with the control group (P = 0.001). These results indicate a significant change in the pH depending on the severity of the periodontal condition. The salivary pH shows significant changes and thus relevance to the severity of periodontal disease. Salivary pH may thus be used as a quick chairside diagnostic biomarker.

  2. Long-term wireless pH monitoring of the distal esophagus: prolonging the test beyond 48 hours is unnecessary and may be misleading.

    Science.gov (United States)

    Capovilla, G; Salvador, R; Spadotto, L; Voltarel, G; Pesenti, E; Perazzolo, A; Nicoletti, L; Merigliano, S; Costantini, M

    2017-10-01

    Wireless pH monitoring of the esophagus has been widely used to detect GERD for more than a decade. It is generally well tolerated and accepted by patients, but it is still unclear whether prolonging a recording beyond the usual 48 hours can improve the test's diagnostic value. The aim of this study is to examine the diagnostic yield of 96-hour pH monitoring vis-à-vis 24- and 48-hour tests, and to ascertain whether any gain in diagnostic terms was of genuine clinical utility. Patients with suspected GERD underwent 4-day PPI-off wireless pH monitoring of the distal esophagus. The capsule was inserted under endoscopic control, 6 cm above the squamocolumnar junction. Average acid exposure time was calculated after 24, 48, and 96 hours of recording. Ninety-nine patients completed the 96 hour test, and formed the study sample. The wireless test method was used in 42 patients (42.4%) unable to tolerate the traditional pH-monitoring catheter, and in 57 (57.6%) with a previous negative pH study despite symptoms suggestive of GERD. On complete analysis, 47 patients (47.5%) had a pathological test result: 19 patients within the first 24 hours (19.2%, 24 hour group); another 16 after 48 hours (+16.2%, 48 hour group), and a further 12 (+12.1%, 96 hour group) only after 96 hours of monitoring. All 47 patients with an abnormal acid exposure were offered and accepted surgery (10 patients) or medical therapy (37 patients). Clinical follow-up was obtained in all patients with a positive Bravo test result after a median 67 months (IQR: 38-98) using a validated symptom questionnaire. A good outcome after fundoplication or medical therapy was achieved in 73.7% of patients in the 24 hour group, in 62.5% of those in the 48 hour group, and in only 25% of those in the 96 hour group, P = 0.02. Long-term wireless pH monitoring enables an increase in the diagnostic yield over traditional 24- and 48-hour pH studies, but prolonging the test may constitute an unwanted bias and prompt the

  3. Tapered Optical Fiber Sensor for Detection of pH in Microscopic Volumes

    Directory of Open Access Journals (Sweden)

    Ondřej PODRAZKÝ

    2014-05-01

    Full Text Available A compact and robust tapered optical fiber microsensor is presented for detection of pH in a range from 5.8 to 7.5 in sub-microliter volumes. The sensor is based on a pH transducer 8- hydroxypyrene-1,3,6-trisulfonic acid trisodium salt immobilized in a xerogel matrix onto the tip of a optical fiber taper with a tip diameter below 20 mm. The sol-gel method and two silicon alkoxides is used for preparing the matrix. A ratio of the fluorescence emission intensities measured at 518 nm after the excitation at 400 and 450 nm is used for evaluating the sensor response to pH. This ratiometric approach enables to reduce effects of ambient light, bleaching of the sensitive layer and geometry of the probe to the fluorescence signal and achieve the resolution of about 0.07 pH units.

  4. Evaluating high pH for control of dreissenid mussels

    Directory of Open Access Journals (Sweden)

    Dave Evans

    2013-04-01

    Full Text Available Two field experiments were carried out using a custom built flow-through laboratory to test the effect of elevated pH on dreissenid musselsas a potential control method. Both experiments tested the ability of dreissenid pediveligers to settle under conditions of elevated pH and thelong-term survival of adult dreissenids under the same conditions. The two experimental sites had different water quality and differentspecies of dreissenids present. The settlement of quagga mussel pediveligers at the lower Colorado River was inhibited with increasing pH.At the maximum achieved pH of 9.1, there was approximately 90% reduction compared to the maximum settlement observed in the controls.Since the settlement was almost as low in pH 8.9 as at pH 9.1, the inhibition in settlement may have been due to the presence of a precipitateformed under high pH conditions rather than the increase in background pH. No mortality of quagga mussel adults was observed in theexperimental pH levels at the lower Colorado River. At San Justo Reservoir, zebra mussel settlement decreased with increasing pH. Newsettlement was almost entirely absent at the highest pH tested (pH 9.6. The observed mortality of adult zebra mussels was low, but did tendto increase with increasing pH. We also tested the response of adult zebra mussels to short-term exposure to very high pH levels (i.e. pH 10,11, and 12. Adult mussels in poor physical condition experienced 90% mortality after 12 hours at pH 12. For unstressed adult zebra mussels,90% mortality was reached after 120 hours at pH 12. Significant mortalities were also observed both at pH 10 and pH 11. From this study,we conclude that pH elevation could be used both as a preventative treatment to eliminate settlement by dreissenid mussels and as an end ofseason treatment to eliminate adults. The high pH treatment would have to be tailored to the site water quality to prevent formation ofprecipitate during treatment and to minimize corrosive

  5. Visual test of subparts per billion-level mercuric ion with a gold nanoparticle probe after preconcentration by hollow fiber supported liquid membrane.

    Science.gov (United States)

    Tan, Zhi-qiang; Liu, Jing-fu

    2010-05-15

    With the combination of the gold nanoparticle (AuNP)-based visual test with hollow fiber supported liquid membrane (HFSLM) extraction, a highly sensitive and selective method was developed for field detection of mercuric ion (Hg(2+)) in environmental waters. Hg(2+) in water samples was extracted through HFSLM and trapped in the aqueous acceptor and then visually detected based on the red-to-blue color change of 3-mercaptopropionic acid-functionalized AuNP (MPA-AuNP) probe. The highest extraction efficiency of Hg(2+) was obtained by using a 600 mL sample (pH 8.0, 2.0% (w/v) NaCl), approximately 35 microL of acceptor (10 mM of 2,6-pyridinedicarboxylic acid, pH 4.0) filled in the lumen of a polypropylene hollow fiber tubing (55 cm in length, 50 microm wall thickness, 280 microm inner diameter), a liquid membrane of 2.0% (w/v) trioctycphosphine oxide in undecane, and a shaking rate of 250 rpm. The chromegenic reaction was conducted by incubating the mixture of MPA-AuNP stock solution (12 microL, 15 nM), Tris-borate buffer solution (18 microL, 0.2 M, pH 9.5), and acceptor (30 microL) at 30 degrees C for 1 h. The detection limit can be adjusted to 0.8 microg/L Hg(2+) (corresponding to an enrichment factor of approximately 1000 in the HFSLM) and 2.0 microg/L Hg(2+) (the U.S. Environmental Protection Agency limit of [Hg(2+)] for drinkable water) by using extraction times of 3 and 1 h, respectively. The proposed method is extremely specific for Hg(2+) with tolerance to at least 1000-fold of other environmentally relevant heavy and transition metal ions and was successfully applied to detect Hg(2+) in a certified reference water sample, as well as real river, lake, and tap water samples.

  6. Radiologic findings after fundoplication compared with a pH reflux test and symptoms

    Energy Technology Data Exchange (ETDEWEB)

    Fransson, S.G.; Soekjer, H.; Johansson, K.E.; Tibbling, L.

    In a follow-up after fundoplication, 61 patients underwent a double contrast examination of the stomach and a radiologic examination to detect any gastro-oesophageal reflux. The radiologic findings were compared with pH reflux test and symptoms. Gastro-oesophageal reflux was found in 7 patients at radiologic examination. None of these patients had an adequate fundoplication at a double contrast examination of the stomach and all had symptoms indicating reflux. Recurrence of gastro-oesophageal reflux may be shown at the radiologic examination and predicted by the morphologic appearances at the double contrast examination.

  7. Radiologic findings after fundoplication compared with a pH reflux test and symptoms

    International Nuclear Information System (INIS)

    Fransson, S.G.; Soekjer, H.; Johansson, K.E.; Tibbling, L.; Linkoeping Univ.; Linkoeping Univ.

    1986-01-01

    In a follow-up after fundoplication, 61 patients underwent a double contrast examination of the stomach and a radiologic examination to detect any gastro-oesophageal reflux. The radiologic findings were compared with pH reflux test and symptoms. Gastro-oesophageal reflux was found in 7 patients at radiologic examination. None of these patients had an adequate fundoplication at a double contrast examination of the stomach and all had symptoms indicating reflux. Recurrence of gastro-oesophageal reflux may be shown at the radiologic examination and predicted by the morphologic appearances at the double contrast examination. (orig.)

  8. pH measurement of tubular vacuoles of an arbuscular mycorrhizal fungus, Gigaspora margarita.

    Science.gov (United States)

    Funamoto, Rintaro; Saito, Katsuharu; Oyaizu, Hiroshi; Aono, Toshihiro; Saito, Masanori

    2015-01-01

    Arbuscular mycorrhizal fungi play an important role in phosphate supply to the host plants. The fungal hyphae contain tubular vacuoles where phosphate compounds such as polyphosphate are accumulated. Despite their importance for the phosphate storage, little is known about the physiological properties of the tubular vacuoles in arbuscular mycorrhizal fungi. As an indicator of the physiological state in vacuoles, we measured pH of tubular vacuoles in living hyphae of arbuscular mycorrhizal fungus Gigaspora margarita using ratio image analysis with pH-dependent fluorescent probe, 6-carboxyfluorescein. Fluorescent images of the fine tubular vacuoles were obtained using a laser scanning confocal microscope, which enabled calculation of vacuolar pH with high spatial resolution. The tubular vacuoles showed mean pH of 5.6 and a pH range of 5.1-6.3. These results suggest that the tubular vacuoles of arbuscular mycorrhizal fungi have a mildly acidic pH just like vacuoles of other fungal species including yeast and ectomycorrhizal fungi.

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

    Science.gov (United States)

    Mendes, Bruna Rafaela; Shimabukuro, Danielle Midori; Uber, Marjorie; Abagge, Kerstin Taniguchi

    2016-01-01

    To evaluate the pH value of children's antibacterial soaps and syndets used in children's baths and verify whether there is information regarding pH on the product label. Quantitative, cross-sectional, analytical observational study that included ninety soap samples, both in bar and liquid presentations, as follows: 67 children's soap (group 1), 17 antibacterial soaps (group 2), and 6 syndets (group 3). Each sample had its pH measured after 1% dilution. In addition to descriptive statistics, the Pearson-Yates chi-squared test and Student's t-tests were applied, considering the minimal significance level of 5%. The Wilcoxon-Mann-Whitney test, Fisher's exact test, and the Kruskal-Wallis test were used for inferential statistics. The pH levels varied considerably between liquid and bar presentations, with lower levels (4.4-7.9) found for the liquids (p<0.05). Syndets showed pH levels close to the ideal (slightly acid) and the antibacterial soaps showed the highest pH levels (up to 11.34) (p<0.05). Only two of the soaps included in the study had information about their pH levels on the product packaging. Knowledge of the pH of children's soap by doctors and users is important, considering the great pH variability found in this study. Moreover, liquid soaps, and especially syndets, are the most recommended for the sensitive skin of neonates and infants, in order to guarantee skin barrier efficacy. Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  10. A quinoline-based Cu2 + ion complex fluorescence probe for selective detection of inorganic phosphate anion in aqueous solution and its application to living cells

    Science.gov (United States)

    Dai, Yanpeng; Wang, Peng; Fu, Jiaxin; Yao, Kun; Xu, Kuoxi; Pang, Xiaobin

    2017-08-01

    A quinaldine functionalized probe QP has been designed and synthesized. It exhibited selective turn-off fluorescence response toward Cu2 + ion over most of the biologically important ions at physiological pH. The binding ratio of the probe QP and Cu2 + ion was determined to be 1:1 through fluorescence titration, Job's plot and ESI-MS. The binding constant (K) of Cu2 + to probe QP was found to be 2.12 × 104 M- 1. Further, the Cu2 + ensemble of probe QP was found to respond H2PO4- and HPO42 - among other important biological anions via fluorescence turn-on response at physiological pH. Fluorescence microscopy imaging using living Hela cells showed that probe QP could be used as an effective fluorescent probe for detecting Cu2 + cation and H2PO4- and HPO42 - anions in living cells.

  11. Direct coupling of electromembrane extraction to mass spectrometry - Advancing the probe functionality toward measurements of zwitterionic drug metabolites.

    Science.gov (United States)

    Rye, Torstein Kige; Fuchs, David; Pedersen-Bjergaard, Stig; Petersen, Nickolaj Jacob

    2017-08-29

    A triple-flow electromembrane extraction (EME) probe was developed and coupled directly to electrospray-ionization mass spectrometry (ESI-MS). Metabolic reaction mixtures (pH 7.4) containing drug substances and related metabolites were continuously drawn (20 μL/min) into the EME probe in one flow channel, and mixed inside the probe with 7.5 μL min -1 of 1 M formic acid as make-up flow from a second flow channel. Following this acidification, the drug substances and their related metabolites were continuously extracted by EME at 400 V, across a supported liquid membrane (SLM) comprising 2-nitrophenyl octyl ether (and for some experiments containing 30% triphenyl phosphate (TPP)), and into 20 μL min -1 of formic acid as acceptor phase, which was introduced through a third flow channel. The acceptor phase was pumped directly to the MS system, and the ion intensity of extracted analytes was followed continuously as function of time. The triple-flow EME probe was used for co-extraction of positively charged parent drugs and their zwitterionic drug metabolites (hydroxyzine and its carboxylic acid metabolite cetirizine; and vortioxetine and its carboxylic acid metabolite Lu AA34443). While the zwitterionic metabolites could not be extracted at pH 7.4, it was shown that by acidifying the sample solution the zwitterionic metabolites could be extracted effectively. Various extraction parameters like make-up flow, extraction voltage and SLM composition were optimized for simultaneous extraction of parent drugs and metabolites. It was found that TPP added to the SLM improved extraction efficiencies of certain drug metabolites. Finally the optimized and characterized triple-flow EME probe was used for online studying the in-vitro metabolism of hydroxyzine and vortioxetine by rat liver microsomes. Due to the automated pre-extraction acidification of the rat liver microsomal solutions, it was possible to continuously monitor formation of the zwitterionic drug

  12. Umbilical Cord Blood pH in Intrapartum Hypoxia.

    Science.gov (United States)

    Perveen, Fouzia; Khan, Ayesha; Ali, Tahmina; Rabia, Syeda

    2015-09-01

    To determine the association of cord arterial blood pH with neonatal outcome in cases of intrapartum fetal hypoxia. Descriptive analytical study. Gynaecology Unit-II, Civil Hospital, Karachi, from September 2011 to November 2012. All singleton cephalic fetuses at term gestation were included in the study. Those with any anomaly, malpresentation, medical disorders, maternal age 7.25, neonatal outcome measures (healthy, NICU admission or neonatal death), color of liquor and mode of delivery recorded on predesigned proforma. Statistical analysis performed by SPSS 16 by using independent-t test or chi-square test and ANOVA test as needed. A total of 204 newborns were evaluated. The mean pH level was found to be significantly different (p=0.007) in two groups. The pH value 7.25 had significant association (p 7.25. Majority (63.6%) cases needed caesarean section as compared to 31.4% controls. There is a significant association of cord arterial blood pH at birth with neonatal outcome at pH 7.25; but below the level of pH 7.25 it is still inconclusive.

  13. Development and application of an excitation ratiometric optical pH sensor for bioprocess monitoring.

    Science.gov (United States)

    Badugu, Ramachandram; Kostov, Yordan; Rao, Govind; Tolosa, Leah

    2008-01-01

    The development of a fluorescent excitation ratiometric pH sensor (AHQ-PEG) using a novel allylhydroxyquinolinium (AHQ) derivative copolymerized with polyethylene glycol dimethacrylate (PEG) is described. The AHQ-PEG sensor film is shown to be suitable for real-time, noninvasive, continuous, online pH monitoring of bioprocesses. Optical ratiometric measurements are generally more reliable, robust, inexpensive, and insensitive to experimental errors such as fluctuations in the source intensity and fluorophore photobleaching. The sensor AHQ-PEG in deionized water was shown to exhibit two excitation maxima at 375 and 425 nm with a single emission peak at 520 nm. Excitation spectra of AHQ-PEG show a decrease in emission at the 360 nm excitation and an increase at the 420 nm excitation with increasing pH. Accordingly, the ratio of emission at 420:360 nm excitation showed a maximum change between pH 5 and 8 with an apparent pK(a) of 6.40. The low pK(a) value is suitable for monitoring the fermentation of most industrially important microorganisms. Additionally, the AHQ-PEG sensor was shown to have minimal sensitivity to ionic strength and temperature. Because AHQ is covalently attached to PEG, the film shows no probe leaching and is sterilizable by steam and alcohol. It shows rapid (approximately 2 min) and reversible response to pH over many cycles without any photobleaching. Subsequently, the AHQ-PEG sensor film was tested for its suitability in monitoring the pH of S. cereviseae (yeast) fermentation. The observed pH using AHQ-PEG film is in agreement with a conventional glass pH electrode. However, unlike the glass electrode, the present sensor is easily adaptable to noninvasive monitoring of sterilized, closed bioprocess environments without the awkward wire connections that electrodes require. In addition, the AHQ-PEG sensor is easily miniaturized to fit in microwell plates and microbioreactors for high-throughput cell culture applications.

  14. Dual-modal cancer detection based on optical pH sensing and Raman spectroscopy.

    Science.gov (United States)

    Kim, Soogeun; Lee, Seung Ho; Min, Sun Young; Byun, Kyung Min; Lee, Soo Yeol

    2017-10-01

    A dual-modal approach using Raman spectroscopy and optical pH sensing was investigated to discriminate between normal and cancerous tissues. Raman spectroscopy has demonstrated the potential for in vivo cancer detection. However, Raman spectroscopy has suffered from strong fluorescence background of biological samples and subtle spectral differences between normal and disease tissues. To overcome those issues, pH sensing is adopted to Raman spectroscopy as a dual-modal approach. Based on the fact that the pH level in cancerous tissues is lower than that in normal tissues due to insufficient vasculature formation, the dual-modal approach combining the chemical information of Raman spectrum and the metabolic information of pH level can improve the specificity of cancer diagnosis. From human breast tissue samples, Raman spectra and pH levels are measured using fiber-optic-based Raman and pH probes, respectively. The pH sensing is based on the dependence of pH level on optical transmission spectrum. Multivariate statistical analysis is performed to evaluate the classification capability of the dual-modal method. The analytical results show that the dual-modal method based on Raman spectroscopy and optical pH sensing can improve the performance of cancer classification. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  15. Dual-modal cancer detection based on optical pH sensing and Raman spectroscopy

    Science.gov (United States)

    Kim, Soogeun; Lee, Seung Ho; Min, Sun Young; Byun, Kyung Min; Lee, Soo Yeol

    2017-10-01

    A dual-modal approach using Raman spectroscopy and optical pH sensing was investigated to discriminate between normal and cancerous tissues. Raman spectroscopy has demonstrated the potential for in vivo cancer detection. However, Raman spectroscopy has suffered from strong fluorescence background of biological samples and subtle spectral differences between normal and disease tissues. To overcome those issues, pH sensing is adopted to Raman spectroscopy as a dual-modal approach. Based on the fact that the pH level in cancerous tissues is lower than that in normal tissues due to insufficient vasculature formation, the dual-modal approach combining the chemical information of Raman spectrum and the metabolic information of pH level can improve the specificity of cancer diagnosis. From human breast tissue samples, Raman spectra and pH levels are measured using fiber-optic-based Raman and pH probes, respectively. The pH sensing is based on the dependence of pH level on optical transmission spectrum. Multivariate statistical analysis is performed to evaluate the classification capability of the dual-modal method. The analytical results show that the dual-modal method based on Raman spectroscopy and optical pH sensing can improve the performance of cancer classification.

  16. Environmental responsiveness of polygalacturonic acid-based multilayers to variation of pH.

    Science.gov (United States)

    Westwood, Marta; Noel, Timothy R; Parker, Roger

    2011-02-14

    The effect of pH on the stability of layer-by-layer deposited polygalacturonic acid (PGalA)-based multilayer films prepared with the polycations poly-L-lysine, chitosan, and lysozyme is studied. The response was characterized using a quartz crystal microbalance, dual polarization interferometry, and Fourier transform infrared spectroscopy which probe multilayer thickness, density, polymer mass (composition and speciation), and hydration. All multilayers showed irreversible changes in response to pH change becoming thinner due to the partial disassembly. Preferential loss of the polycation (50-80% w/w) and relative small losses of PGaLA (10-35% w/w) occurred. The charge density on the polycation has a strong influence on the response to the acid cycle. Most of the disassembly takes place at the pH lower that pK(a) of PGaLA, indicating that this factor was crucial in determining the stability of the films. The pH challenge also revealed a polycation-dependent shift to acid pH in the PGaLA pK(a).

  17. Salivary pH: A diagnostic biomarker

    Directory of Open Access Journals (Sweden)

    Sharmila Baliga

    2013-01-01

    Full Text Available Objectives: Saliva contains a variety of host defense factors. It influences calculus formation and periodontal disease. Different studies have been done to find exact correlation of salivary biomarkers with periodontal disease. With a multitude of biomarkers and complexities in their determination, the salivary pH may be tried to be used as a quick chairside test. The aim of this study was to analyze the pH of saliva and determine its relevance to the severity of periodontal disease. Study Design: The study population consisted of 300 patients. They were divided into three groups of 100 patients each: Group A had clinically healthy gingiva, Group B who had generalized chronic gingivitis and Group C who had generalized chronic periodontitis. The randomized unstimulated saliva from each patient was collected and pH was tested. Data was analyzed statistically using analysis of variance technique. Results: The salivary pH was more alkaline for patients with generalized chronic gingivitis as compared with the control group (P = 0.001 whereas patients with generalized chronic periodontitis had more acidic pH as compared with the control group (P = 0.001. Conclusion: These results indicate a significant change in the pH depending on the severity of the periodontal condition. The salivary pH shows significant changes and thus relevance to the severity of periodontal disease. Salivary pH may thus be used as a quick chairside diagnostic biomarker.

  18. Evaluation of the effect of probe design parameters on ECT signal and development of eddy current probe for irradiated fuel rods

    International Nuclear Information System (INIS)

    Kwank, S. W.; Han, Y. K.; Woo, S. K.; Kim, T. W.; Park, J. Y.; Kim, B. J.; Park, J. Y.

    1999-01-01

    Eddy current test(ECT) is used to inspect not only the failed fuel rods but also peripheral rods during repairing of the failed fuel rods, to detect internal defects in irradiated fuel rods which could not be detected by ultrasonic test and visual test, and to obtain the data for determining the root cause of fuel rod failure. This study evaluates the effect of properties of test article, irradiated fuel rods, on the impedance diagram in order to reduce the difficulty of ECT signal analysis. The optimum eddy current probe design conditions for inspecting the irradiated fuel rods, is estimate by using experimental equations and the probe is manufactured based on the estimated conditions. The performance of developed eddy current probe and the optimum conditions is proved through characteristic comparison experiment with the probe purchased from the foreign vendor

  19. Electrochemical behavior and pH stability of artificial salivas for corrosion tests Comportamento eletroquímico e estabilidade de pH de salivas artificiais para testes de corrosão

    Directory of Open Access Journals (Sweden)

    Gláucia Maria Oliveira de Queiroz

    2007-09-01

    Full Text Available It is assumed that the compositions of artificial salivas are similar to that of human saliva. However, the use of solutions with different compositions in in vitro corrosion studies can lead dissimilar electrolytes to exhibit dissimilar corrosivity and electrochemical stability. This study evaluated four artificial salivas as regards pH stability with time, redox potentials and the polarization response of an inert platinum electrode. The tested solutions were: SAGF medium, Mondelli artificial saliva, UFRJ artificial saliva (prepared at the School of Pharmacy, Federal University of Rio de Janeiro, RJ, Brazil and USP-RP artificial saliva (prepared at the School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, SP, Brazil. It was observed that pH variations were less than 1 unit during a 50-hour test. The SAGF medium, and the UFRJ and USP-RP solutions exhibited more oxidizing characteristics, whereas the Mondelli solution presented reducing properties. Anodic polarization revealed oxidation of the evaluated electrolytes at potentials below +600 mV SCE. It was observed that the UFRJ and USP-RP solutions presented more intense oxidation and reduction processes as compared to the Mondelli and SAGF solutions.Admite-se que as composições das salivas artificiais são semelhantes àquela da saliva humana. A utilização de soluções de composições distintas em estudos de corrosão in vitro, entretanto, pode fazer com que eletrólitos diferentes exibam diferenças no processo corrosivo e na estabilidade eletroquímica. Este estudo avaliou quatro salivas artificiais em relação a estabilidade do pH em função do tempo, potencial redox e resposta à polarização de um eletrodo de platina inerte. As soluções testadas foram: meio SAGF, saliva artificial Mondelli, saliva artificial UFRJ (preparada pela Faculdade de Farmácia da Universidade Federal do Rio de Janeiro, RJ, Brasil e saliva artificial USP-RP (preparada pela

  20. Molecular Wiring in Smart Dressings: Opening a New Route to Monitoring Wound pH

    Directory of Open Access Journals (Sweden)

    Anna McLister

    2015-06-01

    Full Text Available It has been proposed that fluctuations in wound pH can give valuable insights into the healing processes in chronic wounds, but acquiring such data can be a technological challenge especially where there is little sample available. Developments in voltammetric pH sensing have opened up new avenues for the design of probes that can function in ultra-small volumes and can be inherently disposable but, as yet few can meet the demands of wound monitoring. A preliminary investigation of the pH response of a new redox wire prepared from a peptide homopolymer of tryptophan is presented and its potential applicability as a sensing material for use in smart dressings is critically discussed.

  1. Hyperpolarized Amino Acid Derivatives as Multivalent Magnetic Resonance pH Sensor Molecules

    Directory of Open Access Journals (Sweden)

    Christian Hundshammer

    2018-02-01

    Full Text Available pH is a tightly regulated physiological parameter that is often altered in diseased states like cancer. The development of biosensors that can be used to non-invasively image pH with hyperpolarized (HP magnetic resonance spectroscopic imaging has therefore recently gained tremendous interest. However, most of the known HP-sensors have only individually and not comprehensively been analyzed for their biocompatibility, their pH sensitivity under physiological conditions, and the effects of chemical derivatization on their logarithmic acid dissociation constant (pKa. Proteinogenic amino acids are biocompatible, can be hyperpolarized and have at least two pH sensitive moieties. However, they do not exhibit a pH sensitivity in the physiologically relevant pH range. Here, we developed a systematic approach to tailor the pKa of molecules using modifications of carbon chain length and derivatization rendering these molecules interesting for pH biosensing. Notably, we identified several derivatives such as [1-13C]serine amide and [1-13C]-2,3-diaminopropionic acid as novel pH sensors. They bear several spin-1/2 nuclei (13C, 15N, 31P with high sensitivity up to 4.8 ppm/pH and we show that 13C spins can be hyperpolarized with dissolution dynamic polarization (DNP. Our findings elucidate the molecular mechanisms of chemical shift pH sensors that might help to design tailored probes for specific pH in vivo imaging applications.

  2. Hyperpolarized Amino Acid Derivatives as Multivalent Magnetic Resonance pH Sensor Molecules.

    Science.gov (United States)

    Hundshammer, Christian; Düwel, Stephan; Ruseckas, David; Topping, Geoffrey; Dzien, Piotr; Müller, Christoph; Feuerecker, Benedikt; Hövener, Jan B; Haase, Axel; Schwaiger, Markus; Glaser, Steffen J; Schilling, Franz

    2018-02-15

    pH is a tightly regulated physiological parameter that is often altered in diseased states like cancer. The development of biosensors that can be used to non-invasively image pH with hyperpolarized (HP) magnetic resonance spectroscopic imaging has therefore recently gained tremendous interest. However, most of the known HP-sensors have only individually and not comprehensively been analyzed for their biocompatibility, their pH sensitivity under physiological conditions, and the effects of chemical derivatization on their logarithmic acid dissociation constant (p K a ). Proteinogenic amino acids are biocompatible, can be hyperpolarized and have at least two pH sensitive moieties. However, they do not exhibit a pH sensitivity in the physiologically relevant pH range. Here, we developed a systematic approach to tailor the p K a of molecules using modifications of carbon chain length and derivatization rendering these molecules interesting for pH biosensing. Notably, we identified several derivatives such as [1- 13 C]serine amide and [1- 13 C]-2,3-diaminopropionic acid as novel pH sensors. They bear several spin-1/2 nuclei ( 13 C, 15 N, 31 P) with high sensitivity up to 4.8 ppm/pH and we show that 13 C spins can be hyperpolarized with dissolution dynamic polarization (DNP). Our findings elucidate the molecular mechanisms of chemical shift pH sensors that might help to design tailored probes for specific pH in vivo imaging applications.

  3. Imidazole as a pH Probe: An NMR Experiment for the General Chemistry Laboratory

    Science.gov (United States)

    Hagan, William J., Jr.; Edie, Dennis L.; Cooley, Linda B.

    2007-01-01

    The analysis describes an NMR experiment for the general chemistry laboratory, which employs an unknown imidazole solution to measure the pH values. The described mechanism can also be used for measuring the acidity within the isolated cells.

  4. Graphite Screen-Printed Electrodes Applied for the Accurate and Reagentless Sensing of pH.

    Science.gov (United States)

    Galdino, Flávia E; Smith, Jamie P; Kwamou, Sophie I; Kampouris, Dimitrios K; Iniesta, Jesus; Smith, Graham C; Bonacin, Juliano A; Banks, Craig E

    2015-12-01

    A reagentless pH sensor based upon disposable and economical graphite screen-printed electrodes (GSPEs) is demonstrated for the first time. The voltammetric pH sensor utilizes GSPEs which are chemically pretreated to form surface immobilized oxygenated species that, when their redox behavior is monitored, give a Nernstian response over a large pH range (1-13). An excellent experimental correlation is observed between the voltammetric potential and pH over the entire pH range of 1-13 providing a simple approach with which to monitor solution pH. Such a linear response over this dynamic pH range is not usually expected but rather deviation from linearity is encountered at alkaline pH values; absence of this has previously been attributed to a change in the pKa value of surface immobilized groups from that of solution phase species. This non-deviation, which is observed here in the case of our facile produced reagentless pH sensor and also reported in the literature for pH sensitive compounds immobilized upon carbon electrodes/surfaces, where a linear response is observed over the entire pH range, is explained alternatively for the first time. The performance of the GSPE pH sensor is also directly compared with a glass pH probe and applied to the measurement of pH in "real" unbuffered samples where an excellent correlation between the two protocols is observed validating the proposed GSPE pH sensor.

  5. Can quantum probes satisfy the weak equivalence principle?

    International Nuclear Information System (INIS)

    Seveso, Luigi; Paris, Matteo G.A.

    2017-01-01

    We address the question whether quantum probes in a gravitational field can be considered as test particles obeying the weak equivalence principle (WEP). A formulation of the WEP is proposed which applies also in the quantum regime, while maintaining the physical content of its classical counterpart. Such formulation requires the introduction of a gravitational field not to modify the Fisher information about the mass of a freely-falling probe, extractable through measurements of its position. We discover that, while in a uniform field quantum probes satisfy our formulation of the WEP exactly, gravity gradients can encode nontrivial information about the particle’s mass in its wavefunction, leading to violations of the WEP. - Highlights: • Can quantum probes under gravity be approximated as test-bodies? • A formulation of the weak equivalence principle for quantum probes is proposed. • Quantum probes are found to violate it as a matter of principle.

  6. Can quantum probes satisfy the weak equivalence principle?

    Energy Technology Data Exchange (ETDEWEB)

    Seveso, Luigi, E-mail: luigi.seveso@unimi.it [Quantum Technology Lab, Dipartimento di Fisica, Università degli Studi di Milano, I-20133 Milano (Italy); Paris, Matteo G.A. [Quantum Technology Lab, Dipartimento di Fisica, Università degli Studi di Milano, I-20133 Milano (Italy); INFN, Sezione di Milano, I-20133 Milano (Italy)

    2017-05-15

    We address the question whether quantum probes in a gravitational field can be considered as test particles obeying the weak equivalence principle (WEP). A formulation of the WEP is proposed which applies also in the quantum regime, while maintaining the physical content of its classical counterpart. Such formulation requires the introduction of a gravitational field not to modify the Fisher information about the mass of a freely-falling probe, extractable through measurements of its position. We discover that, while in a uniform field quantum probes satisfy our formulation of the WEP exactly, gravity gradients can encode nontrivial information about the particle’s mass in its wavefunction, leading to violations of the WEP. - Highlights: • Can quantum probes under gravity be approximated as test-bodies? • A formulation of the weak equivalence principle for quantum probes is proposed. • Quantum probes are found to violate it as a matter of principle.

  7. Fluorescent pH-Sensing Probe Based on Biorefinery Wood Lignosulfonate and Its Application in Human Cancer Cell Bioimaging.

    Science.gov (United States)

    Xue, Yuyuan; Liang, Wanshan; Li, Yuan; Wu, Ying; Peng, Xinwen; Qiu, Xueqing; Liu, Jinbin; Sun, Runcang

    2016-12-28

    A water-soluble, ratiometric fluorescent pH probe, L-SRhB, was synthesized via grafting spirolactam Rhodamine B (SRhB) to lignosulfonate (LS). As the ring-opening product of L-SRhB, FL-SRhB was also prepared. The pH-response experiment indicated that L-SRhB showed a rapid response to pH changes from 4.60 to 6.20 with a pK a of 5.35, which indicated that L-SRhB has the potential for pH detection of acidic organelle. In addition, the two probes were internalized successfully by living cells through the endocytosis pathway and could distinguish normal cells from cancer cells by different cell staining rates. In addition, L-SRhB showed obvious cytotoxicity to cancer cells, whereas it was nontoxic to normal cells in the same condition. L-SRhB might have potential in cancer therapy. L-SRhB might be a promising ratiometric fluorescent pH sensor and bioimaging dye for the recognition of cancer cells. The results also provided a new perspective to the high-value utilization of lignin.

  8. Isotropic Broadband E-Field Probe

    Directory of Open Access Journals (Sweden)

    Béla Szentpáli

    2008-01-01

    Full Text Available An E-field probe has been developed for EMC immunity tests performed in closed space. The leads are flexible resistive transmission lines. Their influence on the field distribution is negligible. The probe has an isotropic reception from 100 MHz to 18 GHz; the sensitivity is in the 3 V/m–10 V/m range. The device is an accessory of the EMC test chamber. The readout of the field magnitude is carried out by personal computer, which fulfils also the required corrections of the raw data.

  9. Self-Assembled Fluorescent Bovine Serum Albumin Nanoprobes for Ratiometric pH Measurement inside Living Cells.

    Science.gov (United States)

    Yang, Qiaoyu; Ye, Zhongju; Zhong, Meile; Chen, Bo; Chen, Jian; Zeng, Rongjin; Wei, Lin; Li, Hung-wing; Xiao, Lehui

    2016-04-20

    In this work, we demonstrated a new ratiometric method for the quantitative analysis of pH inside living cells. The structure of the nanosensor comprises a biofriendly fluorescent bovine serum albumin (BSA) matrix, acting as a pH probe, and pH-insensitive reference dye Alexa 594 enabling ratiometric quantitative pH measurement. The fluorescent BSA matrix was synthesized by cross-linking of the denatured BSA proteins in ethanol with glutaraldehyde. The size of the as-synthesized BSA nanoparticles can be readily manipulated from 30 to 90 nm, which exhibit decent fluorescence at the peak wavelength of 535 nm with a pH response range of 6-8. The potential of this pH sensor for intracellular pH monitoring was demonstrated inside living HeLa cells, whereby a significant change in fluorescence ratio was observed when the pH of the cell was switched from normal to acidic with anticancer drug treatment. The fast response of the nanosensor makes it a very powerful tool in monitoring the processes occurring within the cytosol.

  10. The quality and testing PH-SFT infrastructure for the external LHC software packages deployment

    CERN Multimedia

    CERN. Geneva; MENDEZ LORENZO, Patricia; MATO VILA, Pere

    2015-01-01

    The PH-SFT group is responsible for the build, test, and deployment of the set of external software packages used by the LHC experiments. This set includes ca. 170 packages including Grid packages and Montecarlo generators provided for different versions. A complete build structure has been established to guarantee the quality of the packages provided by the group. This structure includes an experimental build and three daily nightly builds, each of them dedicated to a specific ROOT version including v6.02, v6.04, and the master. While the former build is dedicated to the test of new packages, versions and dependencies (basically SFT internal used), the three latter ones are the responsible for the deployment to AFS of the set of stable and well tested packages requested by the LHC experiments so they can apply their own builds on top. In all cases, a c...

  11. Probing phosphate ion via the europium(III)-modulated fluorescence of gold nanoclusters

    International Nuclear Information System (INIS)

    Ding, Shou-Nian; Li, Chun-Mei; Gao, Bu-Hong; Kargbo, Osman; Zhou, Chan; Chen, Xi; Wan, Neng

    2014-01-01

    Fluorescent gold nanoclusters (Au-NCs) were synthesized by a one-pot method using 11-mercaptoundecanoic acid as a reducing and capping reagent. It is found that the red fluorescence of the Au-NCs is quenched by the introduction of Eu(III) at pH 7.0, but that fluorescence is restored on addition of phosphate. The Au-NCs were investigated by transmission electron microscopy and fluorescence photographs. The effect of pH on fluorescence was studied in the range from pH 6 to 10 and is found to be strong. Based on these findings, we have developed an assay for phosphate. Ions such as citrate, Fe(CN) 6 3− , SO 4 2− , S 2 O 8 2− , Cl − , HS − , Br − , AcO − , NO 2 − , SCN − , ClO 4 − , HCO 3 − , NO 3 − , Cd 2+ , Ba 2+ , Zn 2+ , Mg 2+ , and glutamate do not interfere, but ascorbate and Fe 3+ can quench Au-NCs fluorescence. The fluorescent nanocluster probe responds to phosphate in the range from 0.18 to 250 μM, and the detection limit is 180 nM. The probe also responds to pyrophosphate and ATP. (author)

  12. Irradiation probe and laboratory for irradiated material evaluation

    International Nuclear Information System (INIS)

    Smutny, S.; Kupca, L.; Beno, P.; Stubna, M.; Mrva, V.; Chmelo, P.

    1975-09-01

    The survey and assessment are given of the tasks carried out in the years 1971 to 1975 within the development of methods for structural materials irradiation and of a probe for the irradiation thereof in the A-1 reactor. The programme and implementation of laboratory tests of the irradiation probe are described. In the actual reactor irradiation, the pulse tube length between the pressure governor and the irradiation probe is approximately 20 m, the diameter is 2.2 mm. Temperature reaches 800 degC while the pressure control system operates at 20 degC. The laboratory tests (carried out at 20 degC) showed that the response time of the pressure control system to a stepwise pressure change in the irradiation probe from 0 to 22 at. is 0.5 s. Pressure changes were also studied in the irradiation probe and in the entire system resulting from temperature changes in the irradiation probe. Temperature distribution in the body of the irradiation probe heating furnace was determined. (B.S.)

  13. Towards Fluorescence In Vivo Hybridization (FIVH) Detection of H. pylori in Gastric Mucosa Using Advanced LNA Probes

    Science.gov (United States)

    Fontenete, Sílvia; Leite, Marina; Guimarães, Nuno; Madureira, Pedro; Ferreira, Rui Manuel; Figueiredo, Céu; Wengel, Jesper; Azevedo, Nuno Filipe

    2015-01-01

    In recent years, there have been several attempts to improve the diagnosis of infection caused by Helicobacter pylori. Fluorescence in situ hybridization (FISH) is a commonly used technique to detect H. pylori infection but it requires biopsies from the stomach. Thus, the development of an in vivo FISH-based method (FIVH) that directly detects and allows the visualization of the bacterium within the human body would significantly reduce the time of analysis, allowing the diagnosis to be performed during endoscopy. In a previous study we designed and synthesized a phosphorothioate locked nucleic acid (LNA)/ 2’ O-methyl RNA (2’OMe) probe using standard phosphoramidite chemistry and FISH hybridization was then successfully performed both on adhered and suspended bacteria at 37°C. In this work we simplified, shortened and adapted FISH to work at gastric pH values, meaning that the hybridization step now takes only 30 minutes and, in addition to the buffer, uses only urea and probe at non-toxic concentrations. Importantly, the sensitivity and specificity of the FISH method was maintained in the range of conditions tested, even at low stringency conditions (e.g., low pH). In conclusion, this methodology is a promising approach that might be used in vivo in the future in combination with a confocal laser endomicroscope for H. pylori visualization. PMID:25915865

  14. Towards Fluorescence In Vivo Hybridization (FIVH Detection of H. pylori in Gastric Mucosa Using Advanced LNA Probes.

    Directory of Open Access Journals (Sweden)

    Sílvia Fontenete

    Full Text Available In recent years, there have been several attempts to improve the diagnosis of infection caused by Helicobacter pylori. Fluorescence in situ hybridization (FISH is a commonly used technique to detect H. pylori infection but it requires biopsies from the stomach. Thus, the development of an in vivo FISH-based method (FIVH that directly detects and allows the visualization of the bacterium within the human body would significantly reduce the time of analysis, allowing the diagnosis to be performed during endoscopy. In a previous study we designed and synthesized a phosphorothioate locked nucleic acid (LNA/ 2' O-methyl RNA (2'OMe probe using standard phosphoramidite chemistry and FISH hybridization was then successfully performed both on adhered and suspended bacteria at 37°C. In this work we simplified, shortened and adapted FISH to work at gastric pH values, meaning that the hybridization step now takes only 30 minutes and, in addition to the buffer, uses only urea and probe at non-toxic concentrations. Importantly, the sensitivity and specificity of the FISH method was maintained in the range of conditions tested, even at low stringency conditions (e.g., low pH. In conclusion, this methodology is a promising approach that might be used in vivo in the future in combination with a confocal laser endomicroscope for H. pylori visualization.

  15. phMRI: methodological considerations for mitigating potential confounding factors

    Directory of Open Access Journals (Sweden)

    Julius H Bourke

    2015-05-01

    Full Text Available Pharmacological Magnetic Resonance Imaging (phMRI is a variant of conventional MRI that adds pharmacological manipulations in order to study the effects of drugs, or uses pharmacological probes to investigate basic or applied (e.g. clinical neuroscience questions. Issues that may confound the interpretation of results from various types of phMRI studies are briefly discussed, and a set of methodological strategies that can mitigate these problems are described. These include strategies that can be employed at every stage of investigation, from study design to interpretation of resulting data, and additional techniques suited for use with clinical populations are also featured. Pharmacological MRI is a challenging area of research that has both significant advantages and formidable difficulties, however with due consideration and use of these strategies many of the key obstacles can be overcome.

  16. Initial dissolution rate of a Japanese simulated high-level waste glass P0798 as a function of pH and temperature measured by using micro-channel flow-through test method

    International Nuclear Information System (INIS)

    Inagaki, Yaohiro; Makigaki, Hikaru; Idemitsu, Kazuya; Arima, Tatsumi; Mitsui, Sei-ichiro; Noshita, Kenji

    2012-01-01

    Aqueous dissolution tests were performed for a Japanese type of simulated high-level waste (HLW) glass P0798 by using a newly developed test method of micro-channel flow-through (MCFT) method, and the initial dissolution rate of glass matrix, r 0 , was measured as a function of solution pH (3-11) and temperature (25-90degC) precisely and consistently for systematic evaluation of the dissolution kinetics. The MCFT method using a micro-channel reactor with a coupon shaped glass specimen has the following features to provide precise and consistent data on the glass dissolution rate: (1) any controlled constant solution condition can be provided over the test duration; (2) the glass surface area actually reacting with solution can be determined accurately; and (3) direct and totally quantitative analyses of the reacted glass surface can be performed for confirming consistency of the test results. The present test results indicated that the r 0 shows a 'V-shaped' pH dependence with a minimum at around pH 6 at 25degC, but it changes to a 'U-shaped' one with a flat bottom at neutral pH at elevated temperatures of up to 90degC. The present results also indicated that the r 0 increases with temperature according to an Arrhenius law at any pH, and the apparent activation energy evaluated from Arrhenius relation increases with pH from 54 kJ/mol at pH 3 to 76 kJ/mol at pH 10, which suggests that the dissolution mechanism changes depending on pH. (author)

  17. Ubiquinone modified printed carbon electrodes for cell culture pH monitoring.

    Science.gov (United States)

    McBeth, Craig; Dughaishi, Rajaa Al; Paterson, Andrew; Sharp, Duncan

    2018-08-15

    The measurement of pH is important throughout many biological systems, but there are limited available technologies to enable its periodical monitoring in the complex, small volume, media often used in cell culture experiments across a range of disciplines. Herein, pad printed electrodes are developed and characterised through modification with: a commercially available fullerene multiwall carbon nanotube composite applied in Nafion, casting of hydrophobic ubiquinone as a pH probe to provide the electrochemical signal, and coated in Polyethylene glycol to reduce fouling and potentially enhance biocompatibility, which together are proven to enable the determination of pH in cell culture media containing serum. The ubiquinone oxidation peak position (E pa ) provided an indirect marker of pH across the applicable range of pH 6-9 (R 2 = 0.9985, n = 15) in complete DMEM. The electrochemical behaviour of these sensors was also proven to be robust; retaining their ability to measure pH in cell culture media supplemented with serum up to 20% (v/v) [encompassing the range commonly employed in cell culture], cycled > 100 times in 10% serum containing media and maintain > 60% functionality after 5 day incubation in a 10% serum containing medium. Overall, this proof of concept research highlights the potential applicability of this, or similar, electrochemical approaches to enable to detection or monitoring of pH in complex cell culture media. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Gamma-ray imaging probes

    International Nuclear Information System (INIS)

    Wild, W.J.

    1988-01-01

    External nuclear medicine diagnostic imaging of early primary and metastatic lung cancer tumors is difficult due to the poor sensitivity and resolution of existing gamma cameras. Nonimaging counting detectors used for internal tumor detection give ambiguous results because distant background variations are difficult to discriminate from neighboring tumor sites. This suggests that an internal imaging nuclear medicine probe, particularly an esophageal probe, may be advantageously used to detect small tumors because of the ability to discriminate against background variations and the capability to get close to sites neighboring the esophagus. The design, theory of operation, preliminary bench tests, characterization of noise behavior and optimization of such an imaging probe is the central theme of this work

  19. NeuroMEMS: Neural Probe Microtechnologies

    Directory of Open Access Journals (Sweden)

    Sam Musallam

    2008-10-01

    Full Text Available Neural probe technologies have already had a significant positive effect on our understanding of the brain by revealing the functioning of networks of biological neurons. Probes are implanted in different areas of the brain to record and/or stimulate specific sites in the brain. Neural probes are currently used in many clinical settings for diagnosis of brain diseases such as seizers, epilepsy, migraine, Alzheimer’s, and dementia. We find these devices assisting paralyzed patients by allowing them to operate computers or robots using their neural activity. In recent years, probe technologies were assisted by rapid advancements in microfabrication and microelectronic technologies and thus are enabling highly functional and robust neural probes which are opening new and exciting avenues in neural sciences and brain machine interfaces. With a wide variety of probes that have been designed, fabricated, and tested to date, this review aims to provide an overview of the advances and recent progress in the microfabrication techniques of neural probes. In addition, we aim to highlight the challenges faced in developing and implementing ultralong multi-site recording probes that are needed to monitor neural activity from deeper regions in the brain. Finally, we review techniques that can improve the biocompatibility of the neural probes to minimize the immune response and encourage neural growth around the electrodes for long term implantation studies.

  20. Fluorescence intensity and lifetime-based cyanide sensitive probes for physiological safeguard

    International Nuclear Information System (INIS)

    Badugu, Ramachandram; Lakowicz, Joseph R.; Geddes, Chris D.

    2004-01-01

    We characterize six new fluorescent probes that show both intensity and lifetime changes in the presence of free uncomplexed aqueous cyanide, allowing for fluorescence based cyanide sensing up to physiological safeguard levels, i.e. 2 to the anionic R-B - (CN) 3 form, a new cyanide binding mechanism which we have recently reported. The presence of an electron deficient quaternary heterocyclic nitrogen nucleus, and the electron rich cyanide bound form, provides for the intensity changes observed. We have determined the disassociation constants of the probes to be in the range ∼15-84 μM 3 . In addition we have synthesized control compounds which do not contain the boronic acid moiety, allowing for a rationale of the cyanide responses between the probe isomers to be made. The lifetime of the cyanide bound probes are significantly shorter than the free R-B(OH) 2 probe forms, providing for the opportunity of lifetime based cyanide sensing up to physiologically lethal levels. Finally, while fluorescent probes containing the boronic acid moiety have earned a well-deserved reputation for monosaccharide sensing, we show that strong bases such as CN - and OH - preferentially bind as compared to glucose, enabling the potential use of these probes for cyanide safeguard and determination in physiological fluids, especially given that physiologies do not experience any notable changes in pH

  1. Eddy current testing probe with dual half-cylindrical coils

    Science.gov (United States)

    Bae, Byung-Hoon; Choi, Jung-Mi; Kim, Soo-Yong

    2000-02-01

    We have developed a new eddy current probe composed of a dual half-cylindrical (2HC) coil as an exciting coil and a sensing coil that is placed in the small gap of the 2HC coil. The 2HC coil induces a linear eddy current on the narrow region within the target medium. The magnitude of eddy current has a maximum peak with the narrow width, underneath the center of the exciting 2HC coil. Because of the linear eddy current, the probe can be used to detect not only the existence of a crack but also its direction in conducting materials. Using specimen with a machined crack, and varying the exciting frequency from 0.5 to 100 kHz, we investigated the relationships between the direction of crack and the output voltage of the sensing coil.

  2. QD-Based FRET Probes at a Glance

    Directory of Open Access Journals (Sweden)

    Armen Shamirian

    2015-06-01

    Full Text Available The unique optoelectronic properties of quantum dots (QDs give them significant advantages over traditional organic dyes, not only as fluorescent labels for bioimaging, but also as emissive sensing probes. QD sensors that function via manipulation of fluorescent resonance energy transfer (FRET are of special interest due to the multiple response mechanisms that may be utilized, which in turn imparts enhanced flexibility in their design. They may also function as ratiometric, or “color-changing” probes. In this review, we describe the fundamentals of FRET and provide examples of QD-FRET sensors as grouped by their response mechanisms such as link cleavage and structural rearrangement. An overview of early works, recent advances, and various models of QD-FRET sensors for the measurement of pH and oxygen, as well as the presence of metal ions and proteins such as enzymes, are also provided.

  3. Coaxial guiding assembly for internal through-passing probe for eddy current testing of tubes

    International Nuclear Information System (INIS)

    Kubis, S.; Holec, P.

    1989-01-01

    The device features guiding cases mounted on springs provided on the peripheries with two rows of radial openings into which are wound flexible fibres parallel with the case axis. The advantage of the design is that active elements which provide the coaxial guiding of the probe are oriented in the direction of the probe movement. This significantly reduces friction between the probe and the internal wall of the tube and thereby also wear of the guide parts of the probe. (J.B.). 2 figs

  4. The effect of pH and DNA concentration on organic thin-film transistor biosensors

    KAUST Repository

    Khan, Hadayat Ullah; Roberts, Mark E.; Johnson, Olasupo B.; Knoll, Wolfgang; Bao, Zhenan

    2012-01-01

    Organic electronics are beginning to attract more interest for biosensor technology as they provide an amenable interface between biology and electronics. Stable biosensor based on electronic detection platform would represent a significant advancement in technology as costs and analysis time would decrease immensely. Organic materials provide a route toward that goal due to their compatibility with electronic applications and biological molecules. In this report, we detail the effects of experimental parameters, such as pH and concentration, toward the selective detection of DNA via surface-bound peptide nucleic acid (PNA) sequences on organic transistor biosensors. The OTFT biosensors are fabricated with thin-films of the organic semiconductor, 5,5′-bis-(7-dodecyl-9H-fluoren-2-yl)-2,2′-bithiophene (DDFTTF), in which they exhibit a stable mobility of 0.2 cm 2 V -1 s -1 in buffer solutions (phosphate-buffer saline, pH 7.4 or sodium acetate, pH 7). Device performance were optimized to minimize the deleterious effects of pH on gate-bias stress such that the sensitivity toward DNA detection can be improved. In titration experiments, the surface-bound PNA probes were saturated with 50 nM of complementary target DNA, which required a 10-fold increase in concentration of single-base mismatched target DNA to achieve a similar surface saturation. The binding constant of DNA on the surface-bound PNA probes was determined from the concentration-dependent response (titration measurements) of our organic transistor biosensors. © 2011 Elsevier B.V. All rights reserved.

  5. The effect of pH and DNA concentration on organic thin-film transistor biosensors

    KAUST Repository

    Khan, Hadayat Ullah

    2012-03-01

    Organic electronics are beginning to attract more interest for biosensor technology as they provide an amenable interface between biology and electronics. Stable biosensor based on electronic detection platform would represent a significant advancement in technology as costs and analysis time would decrease immensely. Organic materials provide a route toward that goal due to their compatibility with electronic applications and biological molecules. In this report, we detail the effects of experimental parameters, such as pH and concentration, toward the selective detection of DNA via surface-bound peptide nucleic acid (PNA) sequences on organic transistor biosensors. The OTFT biosensors are fabricated with thin-films of the organic semiconductor, 5,5′-bis-(7-dodecyl-9H-fluoren-2-yl)-2,2′-bithiophene (DDFTTF), in which they exhibit a stable mobility of 0.2 cm 2 V -1 s -1 in buffer solutions (phosphate-buffer saline, pH 7.4 or sodium acetate, pH 7). Device performance were optimized to minimize the deleterious effects of pH on gate-bias stress such that the sensitivity toward DNA detection can be improved. In titration experiments, the surface-bound PNA probes were saturated with 50 nM of complementary target DNA, which required a 10-fold increase in concentration of single-base mismatched target DNA to achieve a similar surface saturation. The binding constant of DNA on the surface-bound PNA probes was determined from the concentration-dependent response (titration measurements) of our organic transistor biosensors. © 2011 Elsevier B.V. All rights reserved.

  6. Anti-aggregation-based spectrometric detection of Hg(II) at physiological pH using gold nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Rajeshwari, A.; Karthiga, D.; Chandrasekaran, Natarajan; Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com

    2016-10-01

    An efficient detection method for Hg (II) ions at physiological pH (pH 7.4) was developed using tween 20-modified gold nanorods (NRs) in the presence of dithiothreitol (DTT). Thiol groups (-SH) at the end of DTT have a higher affinity towards gold atoms, and they can covalently interact with gold NRs and leads to their aggregation. The addition of Hg(II) ions prevents the aggregation of gold NRs due to the covalent bond formation between the -SH group of DTT and Hg(II) ions in the buffer system. The changes in the longitudinal surface plasmon resonance peak of gold NRs were characterized using a UV–visible spectrophotometer. The absorption intensity peak of gold NRs at 679 nm was observed to reduce after interaction with DTT, and the absorption intensity was noted to increase by increasing the concentration of Hg(II) ions. The TEM analysis confirms the morphological changes of gold NRs before and after addition of Hg(II) ions in the presence of DTT. Further, the aggregation and disaggregation of gold NRs were confirmed by particle size and zeta potential analysis. The developed method shows an excellent linearity (y = 0.001 x + 0.794) for the graph plotted between the absorption ratio and Hg(II) concentration (1 to 100 pM) under the optimized conditions. The limit of detection was noted to be 0.42 pM in the buffer system. The developed method was tested in simulated body fluid, and it was found to have a good recovery rate. - Highlights: • Tween-20 modified gold NRs used as a probe for Hg(II) at physiological pH. • TEM, particle size and surface charge analysis confirm the aggregation and • disaggregation of NRs • The sensitivity of the probe for Hg(II) ions detection was 0.42 pM. • Hg(II) estimation in simulated body fluids with good recovery.

  7. Parathyroid hormone depresses cytosolic pH and DNA synthesis in osteoblast-like cells

    International Nuclear Information System (INIS)

    Reid, I.R.; Civitelli, R.; Avioli, L.V.; Hruska, K.A.

    1988-01-01

    It has recently become apparent that a number of hormones and growth factors modulate cytosolic pH (pH i ) and there is some evidence that this in turn may influence cell growth. The authors have examined the effects of parathyroid hormone (PTH) on both these parameters in an osteoblast-like cell line, UMR 106. Preliminary studies, using the pH-sensitive fluorescent probe 2',7'-bis(2-carboxyethyl)-5,(6)-carboxyfluorescein indicated that these cells regulate pH i by means of an amiloride-inhibitable Na + -H + exchanger. Rat PTH-(1-34) (rPTH) caused a progressive dose-related decrease in pH i with a half-maximal effect at 10 -11 M. The diacylglycerol analogue, phorbol 12-myristate 13-acetate, increased both pH i and [ 3 H]thymidine incorporation, and amiloride reduced both indexes. However, rPTH remained a potent inhibitor of [ 3 H]thymidine incorporation in the presence of amiloride, even though it did not affect pH i in these circumstances. It is concluded that PTH decreases pH i and growth in UMR 106 cells but that these changes can be dissociated. Depression of pH i may have other important effects on bone metabolism, such as reducing cell-cell communication, and may be associated with alkalinization of the bone fluid compartment

  8. IVVS probe mechanical concept design

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Paolo, E-mail: paolo.rossi@enea.it; Neri, Carlo; De Collibus, Mario Ferri; Mugnaini, Giampiero; Pollastrone, Fabio; Crescenzi, Fabio

    2015-10-15

    Highlights: • ENEA designed, developed and tested a laser based In Vessel Viewing System (IVVS). • IVVS mechanical design has been revised from 2011 to 2013 to meet ITER requirements. • Main improvements are piezoceramic actuators and a step focus system. • Successful qualification activities validated the concept design for ITER environment. - Abstract: ENEA has been deeply involved in the design, development and testing of a laser based In Vessel Viewing System (IVVS) required for the inspection of ITER plasma-facing components. The IVVS probe shall be deployed into the vacuum vessel, providing high resolution images and metrology measurements to detect damages and possible erosion. ENEA already designed and manufactured an IVVS probe prototype based on a rad-hard concept and driven by commercial micro-step motors, which demonstrated satisfying viewing and metrology performances at room conditions. The probe sends a laser beam through a reflective rotating prism. By rotating the axes of the prism, the probe can scan all the environment points except those present in a shadow cone and the backscattered light signal is then processed to measure the intensity level (viewing) and the distance from the probe (metrology). During the last years, in order to meet all the ITER environmental conditions, such as high vacuum, gamma radiation lifetime dose up to 5 MGy, cumulative neutron fluence of about 2.3 × 10{sup 17} n/cm{sup 2}, temperature of 120 °C and magnetic field of 8 T, the probe mechanical design was significantly revised introducing a new actuating system based on piezo-ceramic actuators and improved with a new step focus system. The optical and mechanical schemes have been then modified and refined to meet also the geometrical constraints. The paper describes the mechanical concept design solutions adopted in order to fulfill IVVS probe functional performance requirements considering ITER working environment and geometrical constraints.

  9. Monitoring of bentonite pore water with a probe based on solid-state microsensors

    International Nuclear Information System (INIS)

    Orozco, Jahir; Baldi, Antoni; Martin, Pedro L.; Bratov, Andrei; Jimenez, Cecilia

    2006-01-01

    Repositories for the disposal of radioactive waste generally rely on a multi-barrier system to isolate the waste from the biosphere. This multi-barrier system typically comprises Natural geological barrier provided by the repository host rock and its surroundings and an engineered barrier system (EBS). Bentonite is being studied as an appropriated porous material for an EBS to prevent or delay the release and transport of radionuclides towards biosphere. The study of pore water chemistry within bentonite barriers will permit to understand the transport phenomena of radionuclides and obtain a database of the bentonite-water interaction processes. In this work, the measurement of some chemical parameters in bentonite pore water using solid-state microsensors is proposed. Those sensors are well suited for this application since in situ measurements are feasible and they are robust enough for the long periods of time that monitoring is needed in an EBS. A probe containing an ISFET (ion sensitive field effect transistor) for measuring pH, and platinum microelectrodes for measuring conductivity and redox potential was developed, together with the required instrumentation, to study the chemical changes in a test cell with compacted bentonite. Response features of the sensors' probe and instrumentation performance in synthetic samples with compositions similar to those present in bentonite barriers are reported. Measurements of sensors stability in a test cell are also presented

  10. Active auxin uptake by zucchini membrane vesicles: quantitation using ESR volume and delta pH determinations

    International Nuclear Information System (INIS)

    Lomax, T.L.; Mehlhorn, R.J.; Briggs, W.R.

    1985-01-01

    Closed and pH-tight membrane vesicles prepared from hypocotyls of 5-day-old dark-grown seedlings of Cucurbita pepo accumulate the plant growth hormone indole-3-acetic acid along an imposed proton gradient (pH low outside, high inside). The use of electron paramagnetic spin probes permitted quantitation both of apparent vesicle volume and magnitude of the pH gradient. Under the experimental conditions used, hormone accumulation was at minimum 20-fold, a value 4 times larger than what one would predict if accumulation reflected only diffusional equilibrium at the measured pH gradient. It is concluded that hormone uptake is an active process, with each protonated molecule of hormone accompanied by an additional proton. Experiments with ionophores confirm that it is the pH gradient itself which drives the uptake

  11. Development of transient internal probe (TIP) magnetic field diagnostic

    International Nuclear Information System (INIS)

    Galambos, J.P.; Bohnet, M.A.; Jarboe, T.R.; Mattick, A.T.

    1994-01-01

    The Transient Internal Probe (TIP) is designed to permit measurement of internal magnetic fields, in hot, high density plasmas. The concept consists of accelerating a probe to high velocities (2.2 Km/s) in order to minimize probe exposure time to plasma. Faraday rotation within the probe is used to measure the local magnetic field. An Argon laser illuminates the probe consisting of a Faraday-rotator material with a retro-reflector that returns the incident light to the detection system. Performance results of the light gas gun and optical detection system will be shown. To date, the gas gun has been extensively tested consistently achieving velocities between 2 and 3 km/s. The probe and detection scheme have been tested by dropping the probe through a static magnetic field. Magnetic field resolution of 20 gauss and spatial resolution of 5 mm has been achieved. System frequency response is 10Mhz. Work is currently being conducted to integrate the diagnostic system with laboratory plasma experiments. Specifically a gas interfaced system has been developed to prevent helium muzzle gas from entering the plasma chamber with the probe. Additionally the probe must be separated from the sabot which protects the probe during acceleration in the gas gun. Data will be presented showing the results of various separation techniques

  12. ph Sensitive hydrogel as colon specific drug delivery

    International Nuclear Information System (INIS)

    Alarifi, A.S.

    2011-01-01

    γ-radiation induced graft copolymerization and crosslinking was for the synthesis of ph-sensitive hydrogels composed of poly (vinyl pyrrolidone) acrylic acid. The prepared hydrogels were subjected to swelling test to evaluate the effects of ph and ionic strength of the surrounding solution. Drastic changes in the swelling parameters where observed by changing the surrounding solution ph values. The release of ibuprofen from hydrogels was monitored as a function of time at ph 1 and ph 7 in order to evaluate the prepared copolymer ability for colon- specific drug carrier uses.

  13. Platinum(II) complexes as spectroscopic probes for biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Ratilla, E.

    1990-09-21

    The use of platinum(II) complexes as tags and probes for biomolecules is indeed advantageous for their reactivities can be selective for certain purposes through an interplay of mild reaction conditions and of the ligands bound to the platinum. The use of {sup 195}Pt NMR as a method of detecting platinum and its interactions with biomolecules was carried out with the simplest model of platinum(II) tagging to proteins. Variable-temperature {sup 195}Pt NMR spectroscopy proved useful in studying the stereodynamics of complex thioethers like methionine. The complex, Pt(trpy)Cl{sup +}, with its chromophore has a greater potential for probing proteins. It is a noninvasive and selective tag for histidine and cysteine residues on the surface of cytochrome c at pH 5. The protein derivatives obtained are separable, and the tags are easily quantitated and differentiated through the metal-to-ligand charge transfer bands which are sensitive to the environment of the tag. Increasing the pH to 7.0 led to the modification by Pt(trpy)Cl{sup +}of Arg 91 in cytochrome c. Further studies with guanidine-containing ligands as models for arginine modification by Pt(trpy)Cl{sup +} showed that guanidine can act as a terminal ligand and as a bridging ligand. Owing to the potential utility of Pt(trpy)L{sup n+} as electron dense probes of nucleic acid structure, interactions of this bis-Pt(trpy){sup 2+} complex with nucleic acids was evaluated. Indeed, the complex interacts non-covalently with nucleic acids. Its interactions with DNA are not exactly the same as those of its precedents. Most striking is its ability to form highly immobile bands of DNA upon gel electrophoresis. 232 refs.

  14. RGB-Switchable Porous Electrospun Nanofiber Chemoprobe-Filter Prepared from Multifunctional Copolymers for Versatile Sensing of pH and Heavy Metals.

    Science.gov (United States)

    Liang, Fang-Cheng; Kuo, Chi-Ching; Chen, Bo-Yu; Cho, Chia-Jung; Hung, Chih-Chien; Chen, Wen-Chang; Borsali, Redouane

    2017-05-17

    Novel red-green-blue (RGB) switchable probes based on fluorescent porous electrospun (ES) nanofibers exhibiting high sensitivity to pH and mercury ions (Hg 2+ ) were prepared with one type of copolymer (poly(methyl methacrylatete-co-1,8-naphthalimide derivatives-co-rhodamine derivative); poly(MMA-co-BNPTU-co-RhBAM)) by using a single-capillary spinneret. The MMA, BNPTU, and RhBAM moieties were designed to (i) permit formation of porous fibers, (ii) fluoresce for Hg 2+ detection, and (iii) fluoresce for pH, respectively. The fluorescence emission of BNPTU (fluorescence resonance energy transfer (FRET) donor) changed from green to blue as it detected Hg 2+ . The fluorescence emission of RhBAM (FRET acceptor) was highly selective for pH, changing from nonfluorescent (pH 7) to exhibiting strong red fluorescence (pH 2). The full-color emission of the ES nanofibers included green, red, blue, purple, and white depending on the particular pH and Hg 2+ -concentration combination of the solution. The porous ES nanofibers with 30 nm pores were fabricated using hydrophobic MMA, low-boiling-point solvent, and at a high relative humidity (80%). These porous ES nanofibers had a higher surface-to-volume ratio than did the corresponding thin films, which enhanced their performance. The present study demonstrated that the FRET-based full-color-fluorescence porous nanofibrous membranes, which exhibit on-off switching and can be used as naked eye probes, have potential for application in water purification sensing filters.

  15. Test Plan And Procedure For The Examination Of Tank 241-AY-101 Multi-Probe Corrosion Monitoring System

    International Nuclear Information System (INIS)

    Wyrwas, R.B.; Page, J.S.; Cooke, G.S.

    2012-01-01

    This test plan describes the methods to be used in the forensic examination of the Multi-probe Corrosion Monitoring System (MPCMS) installed in the double-shell tank 241-AY-101 (AY-101). The probe was designed by Applied Research and Engineering Sciences (ARES) Corporation. The probe contains four sections, each of which can be removed from the tank independently (H-14-107634, AY-101 MPCMS Removable Probe Assembly) and one fixed center assembly. Each removable section contains three types of passive corrosion coupons: bar coupons, round coupons, and stressed C-rings (H-14-l07635, AY-101 MPCMS Details). Photographs and weights of each coupon were recorded and reported on drawing H-14-107634 and in RPP-RPT-40629, 241-AY-101 MPCMS C-Ring Coupon Photographs. The coupons will be the subject of the forensic analyses. The purpose of this examination will be to document the nature and extent of corrosion of the 29 coupons. This documentation will consist of photographs and photomicrographs of the C-rings and round coupons, as well as the weights of the bar and round coupons during corrosion removal. The total weight loss of the cleaned coupons will be used in conjunction with the surface area of each to calculate corrosion rates in mils per year. The bar coupons were presumably placed to investigate the liquid-air-interface. An analysis of the waste level heights in the waste tank will be investigated as part of this examination.

  16. A PhD is a PhD is a PhD

    OpenAIRE

    Ostrow, Deborah Anne

    2017-01-01

    A PhD is a PhD is a PhD is a practice-based project that interrogates the process of an artist undertaking PhD research under established criteria. It consists of an exegesis, an original screenplay, and a digital film made for online viewing, with images drawn from a range of documentaries and films found on YouTube. They have been dissected, re-assembled and then re-embedded to YouTube. The source material covers topics such as medicalization of madness, the conspicuous appropriation of uni...

  17. Neutralizing salivary pH by mouthwashes after an acidic challenge.

    Science.gov (United States)

    Dehghan, Mojdeh; Tantbirojn, Daranee; Kymer-Davis, Emily; Stewart, Colette W; Zhang, Yanhui H; Versluis, Antheunis; Garcia-Godoy, Franklin

    2017-05-01

    The aim of the present study was to test the neutralizing effect of mouthwashes on salivary pH after an acidic challenge. Twelve participants were recruited for three visits, one morning per week. Resting saliva was collected at baseline and after 2-min swishing with 20 mL orange juice as an acidic challenge. Participants then rinsed their mouth for 30 s with 20 mL water (control), an over-the-counter mouthwash (Listerine), or a two-step mouthwash, randomly assigned for each visit. Saliva was collected immediately, 15, and 45 min after rinsing. The pH values of the collected saliva were measured and analyzed with anova, followed by Student-Newman-Keuls post-hoc test (significance level: 0.05). Orange juice significantly lowered salivary pH. Immediately after rinsing, Listerine and water brought pH back to baseline values, with the pH significantly higher in the Listerine group. The two-step mouthwash raised pH significantly higher than Listerine and water, and higher than the baseline value. Salivary pH returned to baseline and was not significantly different among groups at 15 and 45 min post-rinsing. Mouth rinsing after an acidic challenge increased salivary pH. The tested mouthwashes raised pH higher than water. Mouthwashes with a neutralizing effect can potentially reduce tooth erosion from acid exposure. © 2015 Wiley Publishing Asia Pty Ltd.

  18. Effect of two mouthwashes on salivary ph.

    Science.gov (United States)

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

    2014-01-01

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

  19. Effect of Growth Medium pH of Aeropyrum pernix on Structural Properties and Fluidity of Archaeosomes

    Directory of Open Access Journals (Sweden)

    Ajda Ota

    2012-01-01

    Full Text Available The influence of pH (6.0; 7.0; 8.0 of the growth medium of Aeropyrum pernix K1 on the structural organization and fluidity of archaeosomes prepared from a polar-lipid methanol fraction (PLMF was investigated using fluorescence anisotropy and electron paramagnetic resonance (EPR spectroscopy. Fluorescence anisotropy of the lipophilic fluorofore 1,6-diphenyl-1,3,5-hexatriene and empirical correlation time of the spin probe methylester of 5-doxylpalmitate revealed gradual changes with increasing temperature for the pH. A similar effect has been observed by using the trimethylammonium-6-diphenyl-1,3,5-hexatriene, although the temperature changes were much smaller. As the fluorescence steady-state anisotropy and the empirical correlation time obtained directly from the EPR spectra alone did not provide detailed structural information, the EPR spectra were analysed by computer simulation. This analysis showed that the archaeosome membranes are heterogeneous and composed of several regions with different modes of spin-probe motion at temperatures below 70°C. At higher temperatures, these membranes become more homogeneous and can be described by only one spectral component. Both methods indicate that the pH of the growth medium of A. pernix does not significantly influence its average membrane fluidity. These results are in accordance with TLC analysis of isolated lipids, which show no significant differences between PLMF isolated from A. pernix grown in medium with different pH.

  20. Genetically Targeted Ratiometric and Activated pH Indicator Complexes (TRApHIC) for Receptor Trafficking.

    Science.gov (United States)

    Perkins, Lydia A; Yan, Qi; Schmidt, Brigitte F; Kolodieznyi, Dmytro; Saurabh, Saumya; Larsen, Mads Breum; Watkins, Simon C; Kremer, Laura; Bruchez, Marcel P

    2018-02-06

    Fluorescent protein-based pH sensors are useful tools for measuring protein trafficking through pH changes associated with endo- and exocytosis. However, commonly used pH-sensing probes are ubiquitously expressed with their protein of interest throughout the cell, hindering our ability to focus on specific trafficking pools of proteins. We developed a family of excitation ratiometric, activatable pH responsive tandem dyes, consisting of a pH sensitive Cy3 donor linked to a fluorogenic malachite green acceptor. These cell-excluded dyes are targeted and activated upon binding to a genetically expressed fluorogen-activating protein and are suitable for selective labeling of surface proteins for analysis of endocytosis and recycling in live cells using both confocal and superresolution microscopy. Quantitative profiling of the endocytosis and recycling of tagged β2-adrenergic receptor (B2AR) at a single-vesicle level revealed differences among B2AR agonists, consistent with more detailed pharmacological profiling.

  1. Unsedated peroral wireless pH capsule placement vs. standard pH testing: A randomized study and cost analysis

    Directory of Open Access Journals (Sweden)

    Andrews Christopher N

    2012-05-01

    Full Text Available Abstract Background Wireless capsule pH-metry (WC is better tolerated than standard nasal pH catheter (SC, but endoscopic placement is expensive. Aims: to confirm that non-endoscopic peroral manometric placement of WC is as effective and better tolerated than SC and to perform a cost analysis of the available esophageal pH-metry methods. Methods Randomized trial at 2 centers. Patients referred for esophageal pH testing were randomly assigned to WC with unsedated peroral placement or SC after esophageal manometry (ESM. Primary outcome was overall discomfort with pH-metry. Costs of 3 different pH-metry strategies were analyzed: 1 ESM + SC, 2 ESM + WC and 3 endoscopically placed WC (EGD + WC using publicly funded health care system perspective. Results 86 patients (mean age 51 ± 2 years, 71% female were enrolled. Overall discomfort score was less in WC than in SC patients (26 ± 4 mm vs 39 ± 4 mm VAS, respectively, p = 0.012 but there were no significant group differences in throat, chest, or overall discomfort during placement. Overall failure rate was 7% in the SC group vs 12% in the WC group (p = 0.71. Per patient costs ($Canadian were $1475 for EGD + WC, $1014 for ESM + WC, and $906 for ESM + SC. Decreasing the failure rate of ESM + WC from 12% to 5% decreased the cost of ESM + WC to $991. The ESM + SC and ESM + WC strategies became equivalent when the cost of the WC device was dropped from $292 to $193. Conclusions Unsedated peroral WC insertion is better tolerated than SC pH-metry both overall and during placement. Although WC is more costly, the extra expense is partially offset when the higher patient and caregiver time costs of SC are considered. Trial registration Clinicaltrials.gov Identifier NCT01364610

  2. Corrosion studies of thermally sensitised AGR fuel element brace in pH7 and pH9.2 borate solutions

    International Nuclear Information System (INIS)

    Tyfield, S.P.; Smith, C.A.

    1987-04-01

    Brace and cladding of AGR fuel elements sensitised in reactor are susceptible to intergranular and crevice corrosion, which may initiate in the pH7 borate pond storage environment of CEGB/SSEB stations. This report considers the benefit in corrosion control that is provided by raising the pond solution pH to 9.2, whilst maintaining the boron level at 1250 gm -3 . The greater corrosion protection provided by pH9.2 solution compared to the pH7 borate solution is demonstrated by a series of tests with non-active laboratory sensitised brace samples exposed to solutions dosed with chloride or sulphate in order to promote localised corrosion. The corrosion tests undertaken consisted of 5000 hour immersions at 32 0 C and shorter term electrochemically monitored experiments (rest potential, impedance, anodic current) generally conducted at 22 0 C. The pH9.2 solution effectively inhibited the initiation of crevice and intergranular corrosion in the presence of low levels of chloride and sulphate, whereas the pH7 solution did not always do so. However, the pH9.2 solution, dosed with 40 gm -3 chloride, failed to suppress fully crevice corrosion initiated in unborated 40 gm -3 chloride solution at 22 0 C. Fluoride is not deleterious at low levels ∼ 10 gm -3 in the borate solutions. The significant improvement in corrosion control demonstrated for the change from pH7 to pH9.2 borate solution on laboratory sensitised brace samples should ideally be confirmed using complete irradiated AGR fuel elements. (U.K.)

  3. Pharyngeal pH alone is not reliable for the detection of pharyngeal reflux events: A study with oesophageal and pharyngeal pH-impedance monitoring

    Science.gov (United States)

    Desjardin, Marie; Roman, Sabine; des Varannes, Stanislas Bruley; Gourcerol, Guillaume; Coffin, Benoit; Ropert, Alain; Mion, François

    2013-01-01

    Background Pharyngeal pH probes and pH-impedance catheters have been developed for the diagnosis of laryngo-pharyngeal reflux. Objective To determine the reliability of pharyngeal pH alone for the detection of pharyngeal reflux events. Methods 24-h pH-impedance recordings performed in 45 healthy subjects with a bifurcated probe for detection of pharyngeal and oesophageal reflux events were reviewed. Pharyngeal pH drops to below 4 and 5 were analysed for the simultaneous occurrence of pharyngeal reflux, gastro-oesophageal reflux, and swallows, according to impedance patterns. Results Only 7.0% of pharyngeal pH drops to below 5 identified with impedance corresponded to pharyngeal reflux, while 92.6% were related to swallows and 10.2 and 13.3% were associated with proximal and distal gastro-oesophageal reflux events, respectively. Of pharyngeal pH drops to below 4, 13.2% were related to pharyngeal reflux, 87.5% were related to swallows, and 18.1 and 21.5% were associated with proximal and distal gastro-oesophageal reflux events, respectively. Conclusions This study demonstrates that pharyngeal pH alone is not reliable for the detection of pharyngeal reflux and that adding distal oesophageal pH analysis is not helpful. The only reliable analysis should take into account impedance patterns demonstrating the presence of pharyngeal reflux event preceded by a distal and proximal reflux event within the oesophagus. PMID:24917995

  4. A ph sensor based on a flexible substrate

    Science.gov (United States)

    Huang, Wen-Ding

    pH sensor is an essential component used in many chemical, food, and bio-material industries. Conventional glass electrodes have been used to construct pH sensors, however, have some disadvantages. Glass electrodes are easily affected by alkaline or HF solution, they require a high input impedance pH meter, they often exhibit a sluggish response. In some specific applications, it is also difficult to use glass electrodes for in vivo biomedical or food monitoring applications due to the difficulty of size miniaturization, planarization and polymerization based on current manufacturing technologies. In this work, we have demonstrated a novel flexible pH sensor based on low-cost sol-gel fabrication process of iridium oxide (IrOx) sensing film (IROF). A pair of flexible miniature IrOx/AgCl electrode generated the action potential from the solution by electrochemical mechanism to obtain the pH level of the reagent. The fabrication process including sol-gel, thermal oxidation, and the electro-plating process of the silver chloride (AgCl) reference electrode were reported in the work. The IrOx film was verified and characterized using electron dispersive analysis (EDAX), scanning electron microscope (SEM), and x-ray diffraction (XRD). The flexible pH sensor's performance and characterization have been investigated with different testing parameters such as sensitivity, response time, stability, reversibility, repeatability, selectivity and temperature dependence. The flexible IrOx pH sensors exhibited promising sensing performance with a near-Nernstian response of sensitivity which is between --51.1mV/pH and --51.7mV/pH in different pH levels ranging from 1.5 to 12 at 25°C. Two applications including gastroesophageal reflux disease (GERD) diagnosis and food freshness wireless monitoring using our micro-flexible IrOx pH sensors were demonstrated. For the GERD diagnosing system, we embedded the micro flexible pH sensor on a 1.2cmx3.8cm of the capsule size of wireless sensor

  5. Assessment of salivary calcium, phosphate, magnesium, pH, and flow rate in healthy subjects, periodontitis, and dental caries.

    Science.gov (United States)

    Rajesh, K S; Zareena; Hegde, Shashikanth; Arun Kumar, M S

    2015-01-01

    This study was conducted to estimate and compare inorganic salivary calcium, phosphate, magnesium, salivary flow rate, and pH of unstimulated saliva and oral hygiene status of healthy subjects, subjects with periodontitis and dental caries, and to correlate salivary calcium level with number of intact teeth. The study population consisted of 48 systemically healthy subjects in the age group of 18-55 years, which was further divided into three groups: healthy, periodontitis, and dental caries. Oral hygiene index-simplified, probing pocket depth, clinical attachment level, the number of intact teeth, and active carious lesions were recorded. Estimation of inorganic salivary calcium, phosphate, and magnesium was performed spectrophotometrically using Vitros 5.1 FS. Statistical analysis was performed using the one-way analysis of variance test at 5% significance level. There was a statistically significant increase in inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene status in periodontitis group compared to dental caries and healthy group. Subjects with increased inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene are at a higher risk of developing periodontitis. Since there is increased remineralization potential, these subjects have more number of intact teeth compared to the dental caries group.

  6. Assessment of salivary calcium, phosphate, magnesium, pH, and flow rate in healthy subjects, periodontitis, and dental caries

    Directory of Open Access Journals (Sweden)

    K S Rajesh

    2015-01-01

    Full Text Available Aim: This study was conducted to estimate and compare inorganic salivary calcium, phosphate, magnesium, salivary flow rate, and pH of unstimulated saliva and oral hygiene status of healthy subjects, subjects with periodontitis and dental caries, and to correlate salivary calcium level with number of intact teeth. Materials and Methods: The study population consisted of 48 systemically healthy subjects in the age group of 18-55 years, which was further divided into three groups: healthy, periodontitis, and dental caries. Oral hygiene index-simplified, probing pocket depth, clinical attachment level, the number of intact teeth, and active carious lesions were recorded. Estimation of inorganic salivary calcium, phosphate, and magnesium was performed spectrophotometrically using Vitros 5.1 FS. Statistical analysis was performed using the one-way analysis of variance test at 5% significance level. Results: There was a statistically significant increase in inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene status in periodontitis group compared to dental caries and healthy group. Conclusion: Subjects with increased inorganic salivary calcium, phosphate, pH, flow rate, and poor oral hygiene are at a higher risk of developing periodontitis. Since there is increased remineralization potential, these subjects have more number of intact teeth compared to the dental caries group.

  7. Studies of radiation induced membrane damage in lymphocytes using fluorescent probes

    International Nuclear Information System (INIS)

    Nikesch, W.

    1974-01-01

    The fluorescent probes perylene (PER), 1-anilino-8-naphthalene sulfonic acid (ANS), and fluorescein diacetate (FDA) were used to investigate membrane changes caused by ionizing radiation. Probe response to various other perturbations (variation of pH, temperature, and salt concentration, and treatment with phythohemagglutinin (PHA) and saponins) was also investigated to better understand membrane-probe interactions. ANS was used to probe the membrane surface, PER to probe the membrane interior, and FDA to investigate membrane integrity. Polarization of fluorescent light from ANS and PER was used to investigate the microviscosity and order of the membrane surface and interior respectively. Irradiated cells (600 R) were shown to have a decreased rate of hydrolysis of FDA probably due to cytoplasmic changes effecting the enzymatic reaction. Also evident was an increase in loss of intracellular fluorescein and a decrease in PER polarization indicating that the cells have a decreased membrane integrity, possibly the result of an increased disorganization of the phospholipid hydrocarbon chains in the membrane interior. Experiments with PHA link the decreased membrane integrity with the eventual interphase death of the cells. In general it is shown that the fluorescent probes ANS, PER, and FDA provide useful ways to investigate order and microviscosity in the cell membrane surface and interior, membrane surface charges, internal membrane polarity changes, and membrane integrity. (U.S.)

  8. Surface plasmon resonance based fiber optic pH sensor utilizing Ag/ITO/Al/hydrogel layers.

    Science.gov (United States)

    Mishra, Satyendra K; Gupta, Banshi D

    2013-05-07

    The fabrication and characterization of a surface plasmon resonance based pH sensor using coatings of silver, ITO (In2O3:SnO2), aluminium and smart hydrogel layers over an unclad core of an optical fiber have been reported. The silver, aluminium and ITO layers were coated using a thermal evaporation technique, while the hydrogel layer was prepared using a dip-coating method. The sensor works on the principle of detecting changes in the refractive index of the hydrogel layer due to its swelling and shrinkage caused by changes in the pH of the fluid surrounding the hydrogel layer. The sensor utilizes a wavelength interrogation technique and operates in a particular window of low and high pH values. Increasing the pH value of the fluid causes swelling of the hydrogel layer, which decreases its refractive index and results in a shift of the resonance wavelength towards blue in the transmitted spectra. The thicknesses of the ITO and aluminium layers have been optimized to achieve the best performance of the sensor. The ITO layer increases the sensitivity while the aluminium layer increases the detection accuracy of the sensor. The proposed sensor possesses maximum sensitivity in comparison to the sensors reported in the literature. A negligible effect of ambient temperature in the range 25 °C to 45 °C on the performance of the sensor has been observed. The additional advantages of the sensor are short response time, low cost, probe miniaturization, probe re-usability and the capability of remote sensing.

  9. Design and testing of microfabricated surgical tools for large animal probe insertion

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, Shelly [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-08-05

    Neural probes provide therapeutic stimulation for neuropsychiatric disorders or record neural activity to investigate the workings of the brain. Researchers utilize 6 mm long temporary silicon stiffeners attached with biodissolvable adhesive to insert flexible neural probes into rat brains, but increasing the probe length fivefold makes inserting large animal probes a significant challenge because of an increased potential for buckling. This study compared the insertion success rates of 6 mm and 30 mm long silicon stiffeners that were 80 μm wide and 30 μm thick, and ascertained the material thickness and modulus of elasticity that would provide successful insertion for a 30 mm probe. Using a microdrive, stiffeners were inserted into an agarose brain phantom at controlled insertion speeds while being video-recorded. Twenty-five percent of the 30 mm silicon stiffeners fully inserted at speeds approximately four times higher than the target rate of 0.13 mm/s, while 100 percent of the 6 mm silicon stiffeners inserted successfully at target speed. Critical buckling loads (Pcr) were calculated for the 6 mm and 30 mm silicon stiffeners, and for 30 mm diamond and tungsten stiffeners, with thicknesses varying from 30-80 μm. Increasing the thickness of the material by 10 μm, 20 μm and 30 μm improved the Pcr by 2.4, 4.7 and 8.2 times, respectively, independent of the material, and substituting diamond for silicon multiplied the buckling capacity by 5.0 times. Stiffeners made of silicon for large animal probe insertion are not strong enough to withstand buckling upon insertion without a significant increase in thickness. Replacing silicon with diamond and increasing the thickness of the stiffener to 50 μm would afford a stiffener with the same Pcr capacity as the 6 mm silicon stiffener that had a 100 percent insertion success rate. Experiments should continue with diamond to determine a minimum thickness that will ensure successful

  10. Langmuir probes for SPIDER (source for the production of ions of deuterium extracted from radio frequency plasma) experiment: Tests in BATMAN (Bavarian test machine for negative ions)

    Science.gov (United States)

    Brombin, M.; Spolaore, M.; Serianni, G.; Pomaro, N.; Taliercio, C.; Palma, M. Dalla; Pasqualotto, R.; Schiesko, L.

    2014-11-01

    A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors' holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation. No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns.

  11. Langmuir probes for SPIDER (source for the production of ions of deuterium extracted from radio frequency plasma) experiment: Tests in BATMAN (Bavarian test machine for negative ions)

    International Nuclear Information System (INIS)

    Brombin, M.; Spolaore, M.; Serianni, G.; Pomaro, N.; Taliercio, C.; Palma, M. Dalla; Pasqualotto, R.; Schiesko, L.

    2014-01-01

    A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors’ holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation. No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns

  12. Regional postprandial differences in pH within the stomach and gastroesophageal junction.

    Science.gov (United States)

    Simonian, Hrair P; Vo, Lien; Doma, Siva; Fisher, Robert S; Parkman, Henry P

    2005-12-01

    Our objective was to determine regional differences in intragastric pH after different types of meals. Ten normal subjects underwent 27-hr esophagogastric pH monitoring using a four-probe pH catheter. Meals were a spicy lunch, a high-fat dinner, and a typical bland breakfast. The fatty dinner had the highest postprandial buffering effect, elevating proximal and mid/distal gastric pH to 4.9 +/- 0.4 and 4.0 +/- 0.4, respectively, significantly (P pH > 4 was also longer (150 min) compared to that of the spicy lunch (45 min) and the bland breakfast, which did not increase gastric pH to > 4 at any time. Proximal gastric acid pockets were seen between 15 and 90 min postprandially. These were located 3.4 +/- 0.8 cm below the proximal LES border, extending for a length of 2.3 +/- 0.8 cm, with a drop in mean pH from 4.7 +/- 0.4 to 1.5 +/- 0.9. Acid pockets were seen equally after the spicy lunch and fatty dinner but less frequently after the bland breakfast. We conclude that a high-volume fatty meal has the highest buffering effect on gastric pH compared to a spicy lunch or a bland breakfast. Buffering effects of meals are significantly higher in the proximal than in the mid/distal stomach. Despite the intragastric buffering effect of meals, focal areas of acidity were observed in the region of the cardia-gastroesophageal junction during the postprandial period.

  13. Tunneling Current Probe for Noncontract Wafer-Level Photodiode Array Testing

    National Research Council Canada - National Science Library

    Verdun, Horacio

    1999-01-01

    The Tunneling Current Probe (TCP) is an automated picometer-sensitive proximity sensor and current measurement system which measures the current through a photodiode detector array element by establishing a tunneling current...

  14. Results of performance testing the Russian RPV temperature measurement probe used for annealing

    International Nuclear Information System (INIS)

    Nakos, J.T.; Selsky, S.

    1998-03-01

    This paper provides information on three (3) topics related to temperature measurements in an annealing procedure: (1) results of a series of experiments performed by CNIITMASH of the Russian consortium MOHT on their reactor pressure vessel (RPV) temperature measurement probe, (2) a discussion regarding uncertainties and errors in RPV temperature measurements, and (3) predictions from a thermal model of a spherical RPV temperature measurement probe. MOHT teamed with MPR Associates and was to perform the Annealing Demonstration Project (ADP) on behalf of the US Department of Energy, ESEERCo, EPRI, CRIEPI, Framatome, and Consumers Power Co. at the Midland plant. Experimental results show that the CNIITMASH probe errors are a maximum of about 27 C (49 F) during a 15 C/hr (27 F/hr) heat-up but only about 3 C (5.4 F) (0.6%) during the hold portion at 470 C (878 F). These errors are much smaller than those obtained from a similar series of experiments performed by Sandia National Laboratories (Sandia). The discussion about uncertainties and errors shows that results presented as a temperature difference provides a measure of the probe error. Qualitative agreement is shown between the model predictions, the experimental results of the CNIITMASH probe and the experimental results of a series of similar experiments performed by Sandia

  15. Pitot-probe displacement in a supersonic turbulent boundary layer

    Science.gov (United States)

    Allen, J. M.

    1972-01-01

    Eight circular pitot probes ranging in size from 2 to 70 percent of the boundary-layer thickness were tested to provide experimental probe displacement results in a two-dimensional turbulent boundary layer at a nominal free-stream Mach number of 2 and unit Reynolds number of 8 million per meter. The displacement obtained in the study was larger than that reported by previous investigators in either an incompressible turbulent boundary layer or a supersonic laminar boundary layer. The large probes indicated distorted Mach number profiles, probably due to separation. When the probes were small enough to cause no appreciable distortion, the displacement was constant over most of the boundary layer. The displacement in the near-wall region decreased to negative displacement in some cases. This near-wall region was found to extend to about one probe diameter from the test surface.

  16. Pharmacokinetic and pharmacodynamic effects of two omeprazole formulations on stomach pH and gastric ulcer scores.

    Science.gov (United States)

    Raidal, S L; Andrews, F M; Nielsen, S G; Trope, G

    2017-11-01

    Limited data are available on the relative pharmacokinetics and pharmacodynamics of different omeprazole formulations. To compare pharmacokinetic and pharmacodynamic effects of a novel omeprazole formulation against a currently registered product. Masked 2 period, 2 treatment crossover. Twelve clinically healthy horses were studied over two 6-day treatment periods. Horses were randomly assigned to receive a novel omeprazole paste (Ulcershield: ULS) or a currently registered reference omeprazole product (OMO). Gastric pH was measured continuously for 10 h on the day prior to commencing treatment (Day -1) and after 6 days of oral treatment (Day 5) using in situ antimony pH probes within an indwelling nasogastric tube. Plasma pharmacokinetics were determined on Days 0 and 6. Treatment significantly (Pulcer severity scores (both P = 0.004), with no difference between treatments (P = 0.688). Comparison of mean log area under time-plasma concentration curves demonstrated that, although the lower limit of the 90% confidence interval was within the -20% limit for bioequivalence, the upper limit was exceeded, suggesting that the test product could have greater bioavailability than the reference product. The small sample size, large interhorse plasma omeprazole concentrations, and low bioavailability of omeprazole impacted the sensitivity of the bioequivalence analysis. ULS matched or slightly exceeded OMO plasma concentrations. Both products resulted in equivalent increases in gastric pH, gastric pH profiles and decrease in gastric ulcer scores. Thus, ULS was pharmacodynamically equivalent to OMO and was associated with an equivalent beneficial effect on gastric squamous mucosal ulceration. © 2017 EVJ Ltd.

  17. Proficiency testing materials for pH and blood gases. The California Thoracic Society experience.

    Science.gov (United States)

    Hansen, J E; Clausen, J L; Levy, S E; Mohler, J G; Van Kessel, A L

    1986-02-01

    The California Thoracic Society Blood Gas Proficiency Testing Program distributed ampules from three separate lots of quality control products every three months as unknowns to participating clinical (survey) laboratories and ten selected reference laboratories. For eight quarters, aqueous buffers were distributed. For each lot, PCO2 and pH measurements varied within narrow ranges between laboratories. Concurrently, the PO2 measurements varied widely between reference laboratories as well as survey laboratories, but varied minimally when repeatedly assessed on each reference laboratory machine. Change to a fluorocarbon-containing emulsion as a testing medium resulted in a significant reduction in within model and overall variability for PO2. We attribute this reduction in variability to the higher O2 content and decreased temperature sensitivity for PO2 of the fluorocarbon-containing emulsion. Because we have no evidence that the magnitude of the interinstrument differences in PO2 found with these materials would be found with fresh human blood we recommend that regulatory agencies use the results of proficiency testing for PO2 cautiously.

  18. Electron probe X-ray microanalysis of boar and inobuta testes after the Fukushima accident

    International Nuclear Information System (INIS)

    Yamashiro, Hideaki; Abe, Yasuyuki; Hayashi, Gohei; Urushihara, Yusuke; Kuwahara, Yoshikazu; Suzuki, Masatoshi; Kobayashi, Jin; Kino, Yasuyuki; Fukuda, Tomokazu; Tong, Bin; Takino, Sachio; Sugano, Yukou; Sugimura, Satoshi; Yamada, Takahisa; Isogai, Emiko; Fukumoto, Manabu

    2015-01-01

    We aimed to investigate the effect of chronic radiation exposure associated with the Fukushima Daiichi Nuclear Power Plant (FNPP) accident on the testes of boar and inobuta (a hybrid of Sus scrofa and Sus scrofa domestica). This study examined the contamination levels of radioactive caesium (Cs), especially 134 Cs and 137 Cs, in the testis of both boar and inobuta during 2012, after the Fukushima accident. Morphological analysis and electron-probe X-ray microanalysis (EPMA) were also undertaken on the testes. The 134 Cs and 137 Cs levels were 6430 ± 23 and 6820 ± 32 Bq/kg in the boar testes, and 755 ± 13 and 747 ± 17 Bq/kg in the inobuta testes, respectively. The internal and external exposure of total 134 Cs and 137 Cs in the boar testes were 47.1 mGy and 176.2 mGy, respectively, whereas in the inobuta testes, these levels were 6.09 mGy and 59.8 mGy, respectively. Defective spermatogenesis was not detected by the histochemical analysis of radiation-exposed testes for either animal. In neither animal were Cs molecules detected, using EPMA. In conclusion, we showed that adverse radiation-induced effects were not detected in the examined boar and inobuta testes following the chronic radiation exposure associated with the FNPP accident

  19. Gastric potential difference and pH in ulcer patients and normal volunteers during Stroop's colour word conflict test

    DEFF Research Database (Denmark)

    Højgaard, L; Bendtsen, Flemming

    1989-01-01

    Whether mental stress is important in the pathogenesis of gastric mucosal disorders is not clearly established. This study investigated the relationship between sympathetic activation caused by the Stroop's colour word conflict test and gastric mucosal function, monitored by measuring the gastric...... mucosal electrical potential difference (PD). In 13 healthy volunteers and 12 duodenal ulcer patients gastric PD, pH, and heart rate were measured continuously during basal conditions, during mental stress evoked by the Stroop's colour word conflict test, and after return to basal conditions...

  20. Development of a 16S rRNA-targeted fluorescence in situ hybridization probe for quantification of the ammonia-oxidizer Nitrosotalea devanaterra and its relatives.

    Science.gov (United States)

    Restrepo-Ortiz, C X; Merbt, S N; Barrero-Canossa, J; Fuchs, B M; Casamayor, E O

    2018-04-28

    The Thaumarchaeota SAGMCG-1 group and, in particular, members of the genus Nitrosotalea have high occurrence in acidic soils, the rhizosphere, groundwater and oligotrophic lakes, and play a potential role in nitrogen cycling. In this study, the specific oligonucleotide fluorescence in situ hybridization probe SAG357 was designed for this Thaumarchaeota group based on the available 16S rRNA gene sequences in databases, and included the ammonia-oxidizing species Nitrosotalea devanaterra. Cell permeabilization for catalyzed reporter deposition fluorescence in situ detection and the hybridization conditions were optimized on enrichment cultures of the target species N. devanaterra, as well as the non-target ammonia-oxidizing archaeon Nitrosopumilus maritimus. Probe specificity was improved with a competitor oligonucleotide, and fluorescence intensity and cell visualization were enhanced by the design and application of two adjacent helpers. Probe performance was tested in soil samples along a pH gradient, and counting results matched the expected in situ distributions. Probe SAG357 and the CARD-FISH protocol developed in the present study will help to improve the current understanding of the ecology and physiology of N. devanaterra and its relatives in natural environments. Copyright © 2018 Elsevier GmbH. All rights reserved.

  1. Influence of probe geometry on pitot-probe displacement in supersonic turbulent flow

    Science.gov (United States)

    Allen, J. M.

    1975-01-01

    An experiment was conducted to determine the varying effects of six different probe-tip and support-shaft configurations on pitot tube displacement. The study was stimulated by discrepancies between supersonic wind-tunnel tests conducted by Wilson and Young (1949) and Allen (1972). Wilson (1973) had concluded that these discrepancies were caused by differences in probe geometry. It is shown that in fact, no major differences in profiles of streamwise velocity over streamwise velocity at boundary-layer edge vs normal coordinate over boundary-layer total thickness result from geometry. The true cause of the discrepancies, however, remains to be discovered.

  2. Tumor blood flow and pH changes after glucose administration

    International Nuclear Information System (INIS)

    Thistlethwaite, A.J.; Tupchong, L.; Leeper, D.B.

    1987-01-01

    The authors used a laser doppler technique to correlate blood flow changes with pH changes in human tumors after glucose ingestion. Three PTs with large superficial tumors ingested 100 gm glucose. A 21g needle pH electrode (Micro-electrodes, Inc.) and a 21g ''Laserflo'' fiberoptic laser doppler blood flow probe (TSI, Minneapolis, MN) were used at the same location. Blood glucose was measured by finger stick every 7.5 min. One PT with a squamous cell CA with extensive necrosis had only a small increase in blood glucose and an increase in tumor pH. Blood flow readings were within 6.4-18.4ml/100g/min. Another PT with a squamous CA had a drop in tumor pH (7.46 to 7.05) as blood glucose increased from 85 to 137 mg/dl by 55 min. Blood flow remained in a range of 7.7-13.8 ml/100g/min with a mean of 11.4. The third PT with a sarcoma had tumor pH and blood glucose measurements on two occasions, with similar results. Blood glucose rose from approx. 100 to 150 mg/dl by 52.5 min with a drop in tumor pH from approx. 7.4 to 7.25. On the second trial, tumor blood flow was measured and, while erratic (6.4-24.9ml/100g/min), decreased by approx. 50%. These preliminary data show that the laser doppler blood flow technique is quite sensitive to movement artifact and interference by free hemoglobin. Currently, it is inconclusive whether blood flow is altered with blood glucose and tumor pH changes. Further studies may prove this to be a valuable tool in predicting tumor response to hyperthermia

  3. pH Mapping on Tooth Surfaces for Quantitative Caries Diagnosis Using Micro Ir/IrOx pH Sensor.

    Science.gov (United States)

    Ratanaporncharoen, Chindanai; Tabata, Miyuki; Kitasako, Yuichi; Ikeda, Masaomi; Goda, Tatsuro; Matsumoto, Akira; Tagami, Junji; Miyahara, Yuji

    2018-04-03

    A quantitative diagnostic method for dental caries would improve oral health, which directly affects the quality of life. Here we describe the preparation and application of Ir/IrOx pH sensors, which are used to measure the surface pH of dental caries. The pH level is used as an indicator to distinguish between active and arrested caries. After a dentist visually inspected and defined 18 extracted dentinal caries at various positions as active or arrested caries, the surface pH values of sound and caries areas were directly measured with an Ir/IrOx pH sensor with a diameter of 300 μm as a dental explorer. The average pH values of the sound root, the arrested caries, and active caries were 6.85, 6.07, and 5.30, respectively. The pH obtained with an Ir/IrOx sensor was highly correlated with the inspection results by the dentist, indicating that the types of caries were successfully categorized. This caries testing technique using a micro Ir/IrOx pH sensor provides an accurate quantitative caries evaluation and has potential in clinical diagnosis.

  4. Direct coupling of electromembrane extraction to mass spectrometry – Advancing the probe functionality toward measurements of zwitterionic drug metabolites

    DEFF Research Database (Denmark)

    Kige Rye, Torstein; Fuchs, David; Pedersen-Bjergaard, Stig

    2017-01-01

    A triple-flow electromembrane extraction (EME) probe was developed and coupled directly to electrospray-ionization mass spectrometry (ESI-MS). Metabolic reaction mixtures (pH 7.4) containing drug substances and related metabolites were continuously drawn (20 μL/min) into the EME probe in one flow......-nitrophenyl octyl ether (and for some experiments containing 30% triphenyl phosphate (TPP)), and into 20 μL min-1 of formic acid as acceptor phase, which was introduced through a third flow channel. The acceptor phase was pumped directly to the MS system, and the ion intensity of extracted analytes......, the system can potentially be used for direct analysis of various kinds of chemical reactions that have to be run at pH conditions unfavorable for direct analyte extractions....

  5. Versatile robotic probe calibration for position tracking in ultrasound imaging

    International Nuclear Information System (INIS)

    Bø, Lars Eirik; Hofstad, Erlend Fagertun; Lindseth, Frank; Hernes, Toril A N

    2015-01-01

    Within the field of ultrasound-guided procedures, there are a number of methods for ultrasound probe calibration. While these methods are usually developed for a specific probe, they are in principle easily adapted to other probes. In practice, however, the adaptation often proves tedious and this is impractical in a research setting, where new probes are tested regularly. Therefore, we developed a method which can be applied to a large variety of probes without adaptation. The method used a robot arm to move a plastic sphere submerged in water through the ultrasound image plane, providing a slow and precise movement. The sphere was then segmented from the recorded ultrasound images using a MATLAB programme and the calibration matrix was computed based on this segmentation in combination with tracking information. The method was tested on three very different probes demonstrating both great versatility and high accuracy. (paper)

  6. Versatile robotic probe calibration for position tracking in ultrasound imaging

    Science.gov (United States)

    Eirik Bø, Lars; Fagertun Hofstad, Erlend; Lindseth, Frank; Hernes, Toril A. N.

    2015-05-01

    Within the field of ultrasound-guided procedures, there are a number of methods for ultrasound probe calibration. While these methods are usually developed for a specific probe, they are in principle easily adapted to other probes. In practice, however, the adaptation often proves tedious and this is impractical in a research setting, where new probes are tested regularly. Therefore, we developed a method which can be applied to a large variety of probes without adaptation. The method used a robot arm to move a plastic sphere submerged in water through the ultrasound image plane, providing a slow and precise movement. The sphere was then segmented from the recorded ultrasound images using a MATLAB programme and the calibration matrix was computed based on this segmentation in combination with tracking information. The method was tested on three very different probes demonstrating both great versatility and high accuracy.

  7. DNA probe for lactobacillus delbrueckii

    Energy Technology Data Exchange (ETDEWEB)

    Delley, M.; Mollet, B.; Hottinger, H. (Nestle Research Centre, Lausanne (Switzerland))

    1990-06-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognized L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an {alpha}-{sup 32}P-labeled probe.

  8. DNA probe for lactobacillus delbrueckii

    International Nuclear Information System (INIS)

    Delley, M.; Mollet, B.; Hottinger, H.

    1990-01-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognized L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an α- 32 P-labeled probe

  9. Critical evaluation and further development of methods for testing ecotoxicity at multiple pH using Daphnia magna and Pseudokirchneriella subcapitata

    DEFF Research Database (Denmark)

    Rendal, Cecilie; Trapp, Stefan; Kusk, Kresten Ole

    2012-01-01

    To meet the requirements of risk assessment legislature regarding the ecotoxicity of ionizing compounds, the present study attempts to establish easy, robust methods for testing ecotoxicity at various pH levels. An overview is given of the buffering methods found in the literature...

  10. Raman spectroscopy in investigations of mechanism of binding of human serum albumin to molecular probe fluorescein

    International Nuclear Information System (INIS)

    Vlasova, I M; Saletsky, A M

    2008-01-01

    The mechanism of binding of molecular probe fluorescein to molecules of human serum albumin was studied by the Raman spectroscopy method. The position of binding Center on human serum albumin molecule for fluorescein is determined. The amino acid residues of albumin molecule, participating in binding of fluorescein at different pH values of solution, are established. The conformation rearrangements of globules of human serum albumin, taking place at binding of fluorescein at different pH values of solution, are registered

  11. Synergic effect of salivary pH baselines and low pH intakes on the force relaxation of orthodontic latex elastics.

    Science.gov (United States)

    Ajami, Shabnam; Farjood, Amin; Zare, Mahbubeh

    2017-01-01

    Latex elastics are still in common use due to their low cost and high flexibility to improve sagittal discrepancies or interdigitation of teeth. Mechanical properties of elastics are influenced by several environmental factors such as pH changes. This study evaluated similar latex elastics to define the influence of synergic effect of intermittent low pH and various baselines pH of saliva. Four groups of latex elastics (3-M Unitek, 3/16 inch) were tested ( n = 15 in each group). Two groups of elastics were immersed in two tanks of artificial saliva with different pH levels of 7 and 5, and two groups were immersed in two tanks of artificial saliva with intermittent drop of pH to 4. The force was measured when the elastics were stretched to 25 mm. These measurements were taken in 0, 4, 8, 12, 24, 36, and 48 h for each group. Repeated measures analysis of variance (RMANOVA) and post-hoc Tukey's test were used to assess the findings. The level of significance was 0.05%. The interaction between pH and time analyzed with RMANOVA showed no significant differences ( P > 0.05) except in 36 h ( P = 0.014). The Tukey's analysis showed that each comparison between any two groups did not indicate significant differences ( P > 0.05) except between Groups 1 and 3 and between Groups 2 and 3 ( P pH and force degradation in latex elastic band except in 36 h.

  12. Characteristics Testing of the ECT Bobbin Probe for Steam Generator Tube Inspection of Nuclear Power Plant

    International Nuclear Information System (INIS)

    Nam, Min Woo; Lee, Hee Jong; Cho, Chan hee; Yoo, Hyun Joo

    2010-01-01

    The steam generator management program(SGMP) has recently defined the procedures for the qualification of eddy current hardware and technique. These procedures provide two basic methods for qualification. The first way is to qualify the equipment or the probe by using the flaw mechanism and method of the pulled tubes from the heat exchangers or the artificial flawed tubes. The second way is to verify the equivalency with the characteristics of the qualified equipment or probe. In this case, the qualified equipment or probe may be modified to substitute or replace instruments or probes without re-qualification provided that the range of essential variables defined in the examination technique specification sheet are met. This study is to describe the result of the comparative performance evaluation of bobbin coil eddy current probes manufactured by KEPCO Research Institute and probes manufactured by a foreign manufacturer. As a result of this study, although there were minor differences between the two kinds of probes, it was evaluated that the two kinds of probes were almost identical in the significant performance characteristics described in the KEPCO Research Institute guideline

  13. Characteristics Testing of the ECT Bobbin Probe for Steam Generator Tube Inspection of Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Min Woo; Lee, Hee Jong; Cho, Chan hee; Yoo, Hyun Joo [KEPCO, Daejeon (Korea, Republic of)

    2010-08-15

    The steam generator management program(SGMP) has recently defined the procedures for the qualification of eddy current hardware and technique. These procedures provide two basic methods for qualification. The first way is to qualify the equipment or the probe by using the flaw mechanism and method of the pulled tubes from the heat exchangers or the artificial flawed tubes. The second way is to verify the equivalency with the characteristics of the qualified equipment or probe. In this case, the qualified equipment or probe may be modified to substitute or replace instruments or probes without re-qualification provided that the range of essential variables defined in the examination technique specification sheet are met. This study is to describe the result of the comparative performance evaluation of bobbin coil eddy current probes manufactured by KEPCO Research Institute and probes manufactured by a foreign manufacturer. As a result of this study, although there were minor differences between the two kinds of probes, it was evaluated that the two kinds of probes were almost identical in the significant performance characteristics described in the KEPCO Research Institute guideline

  14. Hubungan antara pH Susu dengan Jumlah Sel Somatik Sebagai Parameter Mastitis Subklinik

    Directory of Open Access Journals (Sweden)

    M. Sudarwanto

    2008-08-01

    Full Text Available The aim of this research was to measure the relationship of the pH value to the somatic cell count as a parameter of sub clinical mastitis detection. Two hundreds quarter milk samples were used in this research and the test (the pH value, IPB-1 mastitis test and Breed method was done in parallel way. The results showed that 152 samples from 200 samples (76% tested with Breed method came from the herds which suffered from sub-clinical mastitis and with IPB-1 test showed that 145 (72.5% of the samples had positive reaction. Using pH meter, it showed that 44 samples (22 % had pH > 6.75, presumed suffered from sub-clinical mastitis and 2 samples (1% showed pH < 6.30 (6.25 and 6.28. At the same time, these two samples showed a negative reaction with IPB-1 test and had somatic cell count of 360,000/ml and 280,000/ml, each. It also showed that there was a close relationship between pH value and IPB-1 test. The conclusion of this research was that the measurement of pH value was not a sensitive method for detecting sub-clinical mastitis.

  15. Design of eddy current probes and signal inversion for non-destructive testing

    International Nuclear Information System (INIS)

    Ravat, C.

    2008-01-01

    Non destructive testing is widely used in aerospace industry and nuclear industry. The growing complexity of industrial processes and manufactured parts, the increasing need of safety in service and the will of life span optimization, require more and more complex quality evaluations to be set up. Among the different anomalies to consider, sub-millimetric breaking surface notches have to be subject to special care. Indeed, it often constitutes a start to larger notches, which can cause the destruction of parts. Penetrant testing is nowadays widely used for that kind of defect, owing to its good performances. Nevertheless, it should be eventually dropped because of environmental norms. Among the possible substitution solutions, the use of eddy currents (EC) for conductive parts is a reliable, fast and inexpensive alternative. The study is about the conception and the use of multi-elements EC probe structures featuring microsensors for non destructive testing of surface breaking defects. A methodology has been established in order to develop such structures and to compare their performances within the framework of sub-millimetric surface breaking notch research. These structures has been employed for calibrated notches evaluation with a specific acquisition bench. Original detection and defect characterization algorithms have been designed and implemented on acquired signals. The most efficient structure has been determined, the notch detection quality has been quantified, and the geometric characteristics of notches has been estimated. (author)

  16. In Situ Live-Cell Nucleus Fluorescence Labeling with Bioinspired Fluorescent Probes.

    Science.gov (United States)

    Ding, Pan; Wang, Houyu; Song, Bin; Ji, Xiaoyuan; Su, Yuanyuan; He, Yao

    2017-08-01

    Fluorescent imaging techniques for visualization of nuclear structure and function in live cells are fundamentally important for exploring major cellular events. The ideal cellular labeling method is capable of realizing label-free, in situ, real-time, and long-term nucleus labeling in live cells, which can fully obtain the nucleus-relative information and effectively alleviate negative effects of alien probes on cellular metabolism. However, current established fluorescent probes-based strategies (e.g., fluorescent proteins-, organic dyes-, fluorescent organic/inorganic nanoparticles-based imaging techniques) are unable to simultaneously realize label-free, in situ, long-term, and real-time nucleus labeling, resulting in inevitable difficulties in fully visualizing nuclear structure and function in live cells. To this end, we present a type of bioinspired fluorescent probes, which are highly efficacious for in situ and label-free tracking of nucleus in long-term and real-time manners. Typically, the bioinspired polydopamine (PDA) nanoparticles, served as fluorescent probes, can be readily synthesized in situ within live cell nucleus without any further modifications under physiological conditions (37 °C, pH ∼7.4). Compared with other conventional nuclear dyes (e.g., propidium iodide (PI), Hoechst), superior spectroscopic properties (e.g., quantum yield of ∼35.8% and high photostability) and low cytotoxicity of PDA-based probes enable long-term (e.g., 3 h) fluorescence tracking of nucleus. We also demonstrate the generality of this type of bioinspired fluorescent probes in different cell lines and complex biological samples.

  17. Dual-Emitting Fluorescent Metal-Organic Framework Nanocomposites as a Broad-Range pH Sensor for Fluorescence Imaging.

    Science.gov (United States)

    Chen, Haiyong; Wang, Jing; Shan, Duoliang; Chen, Jing; Zhang, Shouting; Lu, Xiaoquan

    2018-05-15

    pH plays an important role in understanding physiological/pathologic processes, and abnormal pH is a symbol of many common diseases such as cancer, stroke, and Alzheimer's disease. In this work, an effective dual-emission fluorescent metal-organic framework nanocomposite probe (denoted as RB-PCN) has been constructed for sensitive and broad-range detection of pH. RB-PCN was prepared by encapsulating the DBI-PEG-NH 2 -functionalized Fe 3 O 4 into Zr-MOFs and then further reacting it with rhodamine B isothiocyanates (RBITC). In RB-PCN, RBITC is capable of sensing changes in pH in acidic solutions. Zr-MOFs not only enrich the target analyte but also exhibit a fluorescence response to pH changes in alkaline solutions. Based on the above structural and compositional features, RB-PCN could detect a wide range of pH changes. Importantly, such a nanoprobe could "see" the intracellular pH changes by fluorescence confocal imaging as well as "measure" the wider range of pH in actual samples by fluorescence spectroscopy. To the best of our knowledge, this is the first time a MOF-based dual-emitting fluorescent nanoprobe has been used for a wide range of pH detection.

  18. Preparation of dual-responsive hybrid fluorescent nano probe based on graphene oxide and boronic acid/BODIPY-conjugated polymer for cell imaging

    Energy Technology Data Exchange (ETDEWEB)

    Khoerunnisa [Department of IT Convergence, Korea National University of Transportation, Chungju 380–702 (Korea, Republic of); Kang, Eun Bi [Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380–702 (Korea, Republic of); Mazrad, Zihnil Adha Islamy [Department of IT Convergence, Korea National University of Transportation, Chungju 380–702 (Korea, Republic of); Lee, Gibaek [Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380–702 (Korea, Republic of); In, Insik [Department of IT Convergence, Korea National University of Transportation, Chungju 380–702 (Korea, Republic of); Department of Polymer Science and Engineering, Korea National University of Transportation, Chungju 380–702 (Korea, Republic of); Park, Sung Young, E-mail: parkchem@ut.ac.kr [Department of IT Convergence, Korea National University of Transportation, Chungju 380–702 (Korea, Republic of); Department of Chemical and Biological Engineering, Korea National University of Transportation, Chungju 380–702 (Korea, Republic of)

    2017-02-01

    Here, we report a pH- and thermo-responsive fluorescent nanomaterial of functionalized reduced graphene oxide (rGO) with cross-linked polymer produced via catechol-boronate diol binding mechanism. When conjugated with the hydrophobic dye boron dipyrromethane (BODIPY), this material can act as a dual-responsive nanoplatform for cells imaging. 2-Chloro-3′,4′-dihydroxyacetophenone (CCDP)-quaternized-poly(dimethylaminoethyl methacrylate-co-N-isopropylacrylamide) [C-PDN] was cross-linked with BODIPY and 4-chlorophenyl boronic acid (BA)-quaternized-poly(ethylene glycol)-g-poly(dimethylaminoethyl methacrylate-co-N-isopropylacrylamide) [BB-PPDN]. The GO was then reduced by the catechol group in the cross-linked polymer to synthesize rGO nanoparticles, which able to stabilize the quenching mechanism. This nanoplatform exhibits intense fluorescence at acidic pH and low fluorescence at physiological pH. Confocal laser scanning microscopy (CLSM) images shows bright fluorescence at lysosomal pH and total quench at physiological pH. Therefore, we have successfully developed a promising sensitive bio-imaging probe for identifying cancer cells. - Graphical abstract: [BB-PPDN]-[C-PDN]/rGO nanoparticles with boronic acid-catechol cis-diol binding mechanism toward change in pH demonstrated good biocompatibility and effective quenching for cancer cell detection. - Highlights: • Dual responsive (pH- and thermo) fluorescent nano probe was proposed for cells imaging. • The mechanism was based on cis-diol binding mechanism of boronic acid and catechol. • Reduced graphene oxide was used as quencher on nano-platform. • Detection was controlled dependent on pH based on diol compound of boron chemistry.

  19. 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

    2016-12-09

    Accurate quantitation of intracellular pH (pH i ) 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 pH i 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 pH i . Herein, we have developed a self-ratiometric luminescence nanoprobe based on förster resonant energy transfer (FRET) for probing pH i , 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 NaYF 4 :Yb 3+ , Tm 3+ UCNPs were used as pH i 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 pH i value 3.0-7.0 with deviation less than 0.43. This approach shall facilitate the researches in pH i related areas and development of the intracellular drug delivery systems.

  20. DNA Probe for Lactobacillus delbrueckii

    Science.gov (United States)

    Delley, Michèle; Mollet, Beat; Hottinger, Herbert

    1990-01-01

    From a genomic DNA library of Lactobacillus delbrueckii subsp. bulgaricus, a clone was isolated which complements a leucine auxotrophy of an Escherichia coli strain (GE891). Subsequent analysis of the clone indicated that it could serve as a specific DNA probe. Dot-blot hybridizations with over 40 different Lactobacillus strains showed that this clone specifically recognizes L. delbrueckii subsp. delbrueckii, bulgaricus, and lactis. The sensitivity of the method was tested by using an α-32P-labeled DNA probe. Images PMID:16348233

  1. Indications and interpretation of esophageal function testing.

    Science.gov (United States)

    Gyawali, C Prakash; de Bortoli, Nicola; Clarke, John; Marinelli, Carla; Tolone, Salvatore; Roman, Sabine; Savarino, Edoardo

    2018-05-12

    Esophageal symptoms are common, and can arise from mucosal, motor, functional, and neoplastic processes, among others. Judicious use of diagnostic testing can help define the etiology of symptoms and can direct management. Endoscopy, esophageal high-resolution manometry (HRM), ambulatory pH or pH-impedance manometry, and barium radiography are commonly used for esophageal function testing; functional lumen imaging probe is an emerging option. Recent consensus guidelines have provided direction in using test findings toward defining mechanisms of esophageal symptoms. The Chicago Classification describes hierarchical steps in diagnosing esophageal motility disorders. The Lyon Consensus characterizes conclusive evidence on esophageal testing for a diagnosis of gastroesophageal reflux disease (GERD), and establishes a motor classification of GERD. Taking these recent advances into consideration, our discussion focuses primarily on the indications, technique, equipment, and interpretation of esophageal HRM and ambulatory reflux monitoring in the evaluation of esophageal symptoms, and describes indications for alternative esophageal tests. © 2018 New York Academy of Sciences.

  2. Gravity Probe B: final results of a space experiment to test general relativity.

    Science.gov (United States)

    Everitt, C W F; DeBra, D B; Parkinson, B W; Turneaure, J P; Conklin, J W; Heifetz, M I; Keiser, G M; Silbergleit, A S; Holmes, T; Kolodziejczak, J; Al-Meshari, M; Mester, J C; Muhlfelder, B; Solomonik, V G; Stahl, K; Worden, P W; Bencze, W; Buchman, S; Clarke, B; Al-Jadaan, A; Al-Jibreen, H; Li, J; Lipa, J A; Lockhart, J M; Al-Suwaidan, B; Taber, M; Wang, S

    2011-06-03

    Gravity Probe B, launched 20 April 2004, is a space experiment testing two fundamental predictions of Einstein's theory of general relativity (GR), the geodetic and frame-dragging effects, by means of cryogenic gyroscopes in Earth orbit. Data collection started 28 August 2004 and ended 14 August 2005. Analysis of the data from all four gyroscopes results in a geodetic drift rate of -6601.8±18.3  mas/yr and a frame-dragging drift rate of -37.2±7.2  mas/yr, to be compared with the GR predictions of -6606.1  mas/yr and -39.2  mas/yr, respectively ("mas" is milliarcsecond; 1  mas=4.848×10(-9)  rad).

  3. Influence of oxidation state on the pH dependence of hydrous iridium oxide films

    International Nuclear Information System (INIS)

    Steegstra, Patrick; Ahlberg, Elisabet

    2012-01-01

    Many electrochemical reactions taking place in aqueous solution consume or produce protons. The pH in the diffusion layer can therefore be significantly altered during the reaction and there is a need for in situ pH measurements tracing this near surface pH. In the present paper the rotating ring disc technique was used to measure near surface pH changes during oxygen reduction, utilising hydrous iridium oxide as the pH sensing probe. Before such experiments a good understanding of the pH sensing properties of these films is required and the impact of the oxidation state of the film on the pH sensing properties was investigated as well as the influence of solution redox species. The pH sensitivity (depicted by dE/dpH) was found to depend on the average oxidation state of the film in a manner resembling the cyclic voltammetry response. In all cases the pH response is “supernernstian” with more than one proton per electron. The origin of this behaviour is discussed in the context of acid-base properties of the film and the existence of both hydrous and anhydrous oxide phases. The pH response depends also on the redox properties of the solution but can be optimised for various purposes by conditioning the film at different potentials. This was clearly illustrated by adding hydrogen peroxide, an intermediate in the oxygen reduction reaction, to the solution. It was shown that hydrous iridium oxide can be used as a reliable in situ pH sensor provided that care is taken to optimise the oxidation state of the film.

  4. A dansyl-rhodamine ratiometric fluorescent probe for Hg2+ based on FRET mechanism.

    Science.gov (United States)

    Xie, Puhui; Guo, Fengqi; Wang, Lingyu; Yang, Sen; Yao, Denghui; Yang, Guoyu

    2015-03-01

    Based on resonance energy transfer (FRET) from dansyl to rhodamine 101, a new fluorescent probe (compound 1) containing rhodamine 101 and a dansyl unit was synthesized for detecting Hg(2+) through ratiometric sensing in DMSO aqueous solutions. This probe shows a fast, reversible and selective response toward Hg(2+) in a wide pH range. Hg(2+) induced ring-opening reactions of the spirolactam rhodamine moiety of 1, leading to the formation of fluorescent derivatives that can serve as the FRET acceptors. Very large stokes shift (220 nm) was observed in this case. About 97-fold increase in fluorescence intensity ratio was observed upon its binding with Hg(2+).

  5. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff Mathiasen, Anne-Gitte

    2013-01-01

    Mobile probing is a method, developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time and space......). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings point...... to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  6. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff, Anne-Gitte

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  7. High precision capacitive beam phase probe for KHIMA project

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Ji-Gwang, E-mail: windy206@hanmail.net [Korea Institute of Radiological and Medical Sciences, 215–4, Gongneung-dong, Nowon-t, Seoul 139–706 (Korea, Republic of); Yang, Tae-Keun [Korea Institute of Radiological and Medical Sciences, 215–4, Gongneung-dong, Nowon-t, Seoul 139–706 (Korea, Republic of); Forck, Peter [GSI Helmholtz Centre for Ion Research, Darmstadt 64291, German (Germany)

    2016-11-21

    In the medium energy beam transport (MEBT) line of KHIMA project, a high precision beam phase probe monitor is required for a precise tuning of RF phase and amplitude of Radio Frequency Quadrupole (RFQ) accelerator and IH-DTL linac. It is also used for measuring a kinetic energy of ion beam by time-of-flight (TOF) method using two phase probes. The capacitive beam phase probe has been developed. The electromagnetic design of the high precision phase probe was performed to satisfy the phase resolution of 1° (@200 MHz). It was confirmed by the test result using a wire test bench. The measured phase accuracy of the fabricated phase probe is 1.19 ps. The pre-amplifier electronics with the 0.125 ∼ 1.61 GHz broad-band was designed and fabricated for amplifying the signal strength. The results of RF frequency and beam energy measurement using a proton beam from the cyclotron in KIRAMS is presented.

  8. Iridium Oxide pH Sensor Based on Stainless Steel Wire for pH Mapping on Metal Surface

    Science.gov (United States)

    Shahrestani, S.; Ismail, M. C.; Kakooei, S.; Beheshti, M.; Zabihiazadboni, M.; Zavareh, M. A.

    2018-03-01

    A simple technique to fabricate the iridium oxide pH sensor is useful in several applications such as medical, food processing and engineering material where it is able to detect the changes of pH. Generally, the fabrication technique can be classified into three types: electro-deposition iridium oxide film (EIrOF), activated iridium oxide film (AIROF) and sputtering iridium oxide film (SIROF). This study focuses on fabricating electrode, calibration and test. Electro-deposition iridium oxide film is a simple and effective method of fabricating this kind of sensor via cyclic voltammetry process. The iridium oxide thick film was successfully electrodeposited on the surface of stainless steel wire with 500 cycles of sweep potential. A further analysis under FESEM shows detailed image of iridium oxide film which has cauliflower-liked microstructure. EDX analysis shows the highest element present are iridium and oxygen which concluded that the process is successful. The iridium oxide based pH sensor has shown a good performance in comparison to conventional glass pH sensor when it is being calibrated in buffer solutions with 2, 4, 7 and 9 pH values. The iridium oxide pH sensor is specifically designed to measure the pH on the surface of metal plate.

  9. Relieving Dry Mouth: Varying Levels of pH Found in Bottled Water.

    Science.gov (United States)

    Fisher, Bailey Jean; Spencer, Angela; Haywood, Van; Konchady, Gayathri

    2017-07-01

    It is estimated that 30% of people older than 60 years suffer from hyposalivation or dry mouth. Drinking water frequently has been recommended as a safe, non-pharmacologic way to combat hyposalivation. The saliva in patients with dry mouth is acidic. Beverages consumed daily may have an erosive potential on teeth. The pH and the mineral content of the beverage determine its erosive potential. An acidic beverage, therefore, may have harmful effects on mineralized tooth structures, causing erosion of enamel, dentin, and cementum. Because bottled water is both convenient and easily available, the authors tested the pH of eight common brands of bottled water. (One brand included two different bottle types, for a total of nine bottled waters tested.) To standardize the pH electrode, pH buffers of 4.7 and 10 were used. The pH was measured using the Denver Instruments basic pH meter. Six recordings were used for each brand and then averaged to report the pH. Two of the bottled water samples tested were below the critical level of 5.2 pH to 5.5 pH, the level at which erosion of enamel occurs. Six of the samples tested were below the critical pH of 6.8, at which erosion of root dentin occurs. The authors conclude that both patients and clinicians incorrectly presume bottled water to be innocuous. Clinicians should be cognizant of the erosive potential of different brands of bottled water to both educate patients and to recommend water with neutral or alkaline pH for patients with symptoms of dry mouth to prevent further deterioration and demineralization of tooth structure.

  10. Intra-albumin migration of bound fatty acid probed by spin label ESR

    International Nuclear Information System (INIS)

    Gurachevsky, Andrey; Shimanovitch, Ekaterina; Gurachevskaya, Tatjana; Muravsky, Vladimir

    2007-01-01

    Conventional ESR spectra of 16-doxyl-stearic acid bound to bovine and human serum albumin were recorded at different temperatures in order to investigate the status of spin-labeled fatty acid in the interior of the protein globule. A computer spectrum simulation of measured spectra, performed by non-linear least-squares fits, clearly showed two components corresponding to strongly and weakly immobilized fatty acid molecules. The two-component model was verified on spectra measured at different pH. Thermodynamic parameters of the spin probe exchange between two spin probe states were analyzed. It was concluded that at physiological conditions, fatty acid molecules permanently migrate in the globule interior between the specific binding sites and a space among albumin domains

  11. Automated design of genomic Southern blot probes

    Directory of Open Access Journals (Sweden)

    Komiyama Noboru H

    2010-01-01

    Full Text Available Abstract Background Sothern blotting is a DNA analysis technique that has found widespread application in molecular biology. It has been used for gene discovery and mapping and has diagnostic and forensic applications, including mutation detection in patient samples and DNA fingerprinting in criminal investigations. Southern blotting has been employed as the definitive method for detecting transgene integration, and successful homologous recombination in gene targeting experiments. The technique employs a labeled DNA probe to detect a specific DNA sequence in a complex DNA sample that has been separated by restriction-digest and gel electrophoresis. Critically for the technique to succeed the probe must be unique to the target locus so as not to cross-hybridize to other endogenous DNA within the sample. Investigators routinely employ a manual approach to probe design. A genome browser is used to extract DNA sequence from the locus of interest, which is searched against the target genome using a BLAST-like tool. Ideally a single perfect match is obtained to the target, with little cross-reactivity caused by homologous DNA sequence present in the genome and/or repetitive and low-complexity elements in the candidate probe. This is a labor intensive process often requiring several attempts to find a suitable probe for laboratory testing. Results We have written an informatic pipeline to automatically design genomic Sothern blot probes that specifically attempts to optimize the resultant probe, employing a brute-force strategy of generating many candidate probes of acceptable length in the user-specified design window, searching all against the target genome, then scoring and ranking the candidates by uniqueness and repetitive DNA element content. Using these in silico measures we can automatically design probes that we predict to perform as well, or better, than our previous manual designs, while considerably reducing design time. We went on to

  12. Double-pass Mach-Zehnder fiber interferometer pH sensor.

    Science.gov (United States)

    Tou, Zhi Qiang; Chan, Chi Chiu; Hong, Jesmond; Png, Shermaine; Eddie, Khay Ming Tan; Tan, Terence Aik Huang

    2014-04-01

    A biocompatible fiber-optic pH sensor based on a unique double-pass Mach-Zehnder interferometer is proposed. pH responsive poly(2-hydroxyethyl methacrylate-co-2-(dimethylamino)ethyl methacrylate) hydrogel coating on the fiber swells/deswells in response to local pH, leading to refractive index changes that manifest as shifting of interference dips in the optical spectrum. The pH sensor is tested in spiked phosphate buffer saline and demonstrates high sensitivity of 1.71  nm/pH, pH 0.004 limit of detection with good responsiveness, repeatability, and stability. The proposed sensor has been successfully applied in monitoring the media pH in cell culture experiments to investigate the relationship between pH and cancer cell growth.

  13. Results of testing the E9 multiple probe lateral logging device in deep wells in the eastern Pre-caucasus

    Energy Technology Data Exchange (ETDEWEB)

    Boyarchuk, A.F.; Kochetkov, V.T.; Kucherov, R.A.

    1981-07-01

    The integrated lateral logging device E9 developed for investigating deep and extra-deep wells, permitting measurement of apparent resistances by three probes at different depths, is described. It is heat and pressure resistant (up to 200/degree/C, 120 MPa). The tests showed that under certain favorable conditions the device is fairly effective.

  14. Soil pH mapping with an on-the-go sensor.

    Science.gov (United States)

    Schirrmann, Michael; Gebbers, Robin; Kramer, Eckart; Seidel, Jan

    2011-01-01

    Soil pH is a key parameter for crop productivity, therefore, its spatial variation should be adequately addressed to improve precision management decisions. Recently, the Veris pH Manager™, a sensor for high-resolution mapping of soil pH at the field scale, has been made commercially available in the US. While driving over the field, soil pH is measured on-the-go directly within the soil by ion selective antimony electrodes. The aim of this study was to evaluate the Veris pH Manager™ under farming conditions in Germany. Sensor readings were compared with data obtained by standard protocols of soil pH assessment. Experiments took place under different scenarios: (a) controlled tests in the lab, (b) semicontrolled test on transects in a stop-and-go mode, and (c) tests under practical conditions in the field with the sensor working in its typical on-the-go mode. Accuracy issues, problems, options, and potential benefits of the Veris pH Manager™ were addressed. The tests demonstrated a high degree of linearity between standard laboratory values and sensor readings. Under practical conditions in the field (scenario c), the measure of fit (r(2)) for the regression between the on-the-go measurements and the reference data was 0.71, 0.63, and 0.84, respectively. Field-specific calibration was necessary to reduce systematic errors. Accuracy of the on-the-go maps was considerably higher compared with the pH maps obtained by following the standard protocols, and the error in calculating lime requirements was reduced by about one half. However, the system showed some weaknesses due to blockage by residual straw and weed roots. If these problems were solved, the on-the-go sensor investigated here could be an efficient alternative to standard sampling protocols as a basis for liming in Germany.

  15. Regional gastrointestinal transit and pH studied in 215 healthy volunteers using the wireless motility capsule: influence of age, gender, study country and testing protocol.

    Science.gov (United States)

    Wang, Y T; Mohammed, S D; Farmer, A D; Wang, D; Zarate, N; Hobson, A R; Hellström, P M; Semler, J R; Kuo, B; Rao, S S; Hasler, W L; Camilleri, M; Scott, S M

    2015-09-01

    The wireless motility capsule (WMC) offers the ability to investigate luminal gastrointestinal (GI) physiology in a minimally invasive manner. To investigate the effect of testing protocol, gender, age and study country on regional GI transit times and associated pH values using the WMC. Regional GI transit times and pH values were determined in 215 healthy volunteers from USA and Sweden studied using the WMC over a 6.5-year period. The effects of test protocol, gender, age and study country were examined. For GI transit times, testing protocol was associated with differences in gastric emptying time (GET; shorter with protocol 2 (motility capsule ingested immediately after meal) vs. protocol 1 (motility capsule immediately before): median difference: 52 min, P = 0.0063) and colonic transit time (CTT; longer with protocol 2: median 140 min, P = 0.0189), but had no overall effect on whole gut transit time. Females had longer GET (by median 17 min, P = 0.0307), and also longer CTT by (104 min, P = 0.0285) and whole gut transit time by (263 min, P = 0.0077). Increasing age was associated with shorter small bowel transit time (P = 0.002), and study country also influenced small bowel and CTTs. Whole gut and CTTs showed clustering of data at values separated by 24 h, suggesting that describing these measures as continuous variables is invalid. Testing protocol, gender and study country also significantly influenced pH values. Regional GI transit times and pH values, delineated using the wireless motility capsule (WMC), vary based on testing protocol, gender, age and country. Standardisation of testing is crucial for cross-referencing in clinical practice and future research. © 2015 John Wiley & Sons Ltd.

  16. An updated pH calculation tool for new challenges

    Energy Technology Data Exchange (ETDEWEB)

    Crolet, J.L. [Consultant, 36 Chemin Mirassou, 64140 Lons (France)

    2004-07-01

    The time evolution of the in-situ pH concept is summarised, as well as the past and present challenges of pH calculations. Since the beginning of such calculations on spread sheets, the tremendous progress in the computer technology has progressively removed all its past limitations. On the other hand, the development of artificial acetate buffering in standardized and non-standardized corrosion testing has raised quite a few new questions. Especially, a straightforward precautionary principle now requires to limit all what is artificial to situations where this is really necessary and, consequently, seriously consider the possibility of periodic pH readjustment as an alternative to useless or excessive artificial buffering, including in the case of an over-acidification at ambient pressure through HCl addition only (e.g. SSC testing of martensitic stainless steels). These new challenges require a genuine 'pH engineering' for the design of corrosion testing protocols under CO{sub 2} and H{sub 2}S partial pressures, at ambient pressure or in autoclave. In this aim, not only a great many detailed pH data shall be automatically delivered to unskilled users, but this shall be done in an experimental context which is most often new and much more complicated than before: e.g. pH adjustment of artificial buffers before saturation in the test gas and further pH evolution under acid gas pressure (pH shift before test beginning), anticipation of the pH readjustment frequency from just a volume / surface ratio and an expected corrosion rate (pH drift during the test). Furthermore, in order to be really useful and reliable, such numerous pH data have also to be well understood. Therefore, their origin, significance and parametric sensitivity are backed up and explained through three self-understanding graphical illustrations: 1. an 'anion - pH' nomogram shows the pH dependence of all the variable ions, H{sup +}, HCO{sub 3}{sup -}, HS{sup -}, Ac{sup -} (and

  17. Design of 240,000 orthogonal 25mer DNA barcode probes.

    Science.gov (United States)

    Xu, Qikai; Schlabach, Michael R; Hannon, Gregory J; Elledge, Stephen J

    2009-02-17

    DNA barcodes linked to genetic features greatly facilitate screening these features in pooled formats using microarray hybridization, and new tools are needed to design large sets of barcodes to allow construction of large barcoded mammalian libraries such as shRNA libraries. Here we report a framework for designing large sets of orthogonal barcode probes. We demonstrate the utility of this framework by designing 240,000 barcode probes and testing their performance by hybridization. From the test hybridizations, we also discovered new probe design rules that significantly reduce cross-hybridization after their introduction into the framework of the algorithm. These rules should improve the performance of DNA microarray probe designs for many applications.

  18. Exploring B/Ca as a pH proxy in bivalves: relationships between Mytilus californianus B/Ca and environmental data from the northeast Pacific

    Directory of Open Access Journals (Sweden)

    N. Shimizu

    2011-09-01

    Full Text Available A distinct gap in our ability to understand changes in coastal biology that may be associated with recent ocean acidification is the paucity of directly measured ocean environmental parameters at coastal sites in recent decades. Thus, many researchers have turned to sclerochronological reconstructions of water chemistry to document the historical seawater environment. In this study, we explore the relationships between B/Ca and pH to test the feasibility of B/Ca measured on the ion probe as a pH proxy in the California mussel, Mytilus californianus. Heterogeneity in a range of ion microprobe standards is assessed, leading to reproducible B/Ca ratios at the 5% level. The B/Ca data exhibit large excursions during winter months, which are particularly pronounced during the severe winters of 2004–2005 and 2005–2006. Furthermore, B/Ca ratios are offset in different parts of the skeleton that calcified at the same time. We compare the M. californianus B/Ca record to directly measured environmental data during mussel growth from the period of 1999–2009 to examine whether seawater chemistry or temperature plays a role in controlling shell B/Ca. A suite of growth rate models based on measured temperature are compared to the B/Ca data to optimise the potential fit of B/Ca to pH. Despite sampling conditions that were well-suited to testing a pH control on B/Ca, including a close proximity to an environmental record, a distinct change in pH at the sampling locale, and a growth model designed to optimise the correlations between seawater pH and shell B/Ca, we do not see a strong correlations between pH and shell B/Ca (maximum coefficient of determination, r2, of 0.207. Instead, our data indicate a strong biological control on B/Ca as observed in some other carbonate-forming organisms.

  19. Effect of low pH on the survival and emergence of aquatic insects

    Energy Technology Data Exchange (ETDEWEB)

    Bell, H L

    1971-01-01

    Mature larvae and nymphs of 9 species of aquatic insects (dragonflies, stoneflies, caddisflies, and mayfly) were tested in the laboratory at pH values from 1.0 to 7.0. The tl/sub 50/ values (pH at which 50 per cent of the organisms died) at 30 days ranged from pH 2.45 (Brachycentrus americanus) to pH 5.38 (Ephemeralla subvaria). The range at which 50 per cent of the insects emerged was pH 4.0 -5.9. The 9 species tested were all more sensitive to low pH during the period of emergence.

  20. An Experimental Evaluation of the Performance of Two Combination Pitot Pressure Probes

    Science.gov (United States)

    Arend, David J.; Saunders, John D.

    2009-01-01

    Experimental tests have been completed which recorded the ability of two combination steady state and high response time varying Pitot probe designs to accurately measure steady stagnation pressure at a single location in a flow field. Tests were conducted of double-barreled and coannular Prati probes in a 3.5 in. diameter free jet probe calibration facility from Mach 0.1 to 0.9. Geometric symmetry and pitch (-40 deg to 40 deg) and yaw (0 deg to 40 deg) angle actuation were used to fully evaluate the probes. These tests revealed that the double-barreled configuration induced error in its steady state measurement at zero incidence that increased consistently with jet Mach number to 1.1 percent at Mach 0.9. For all Mach numbers, the double-barreled probe nulled at a pitch angle of approximately 7.0 deg and provided inconsistent measurements when yawed. The double-barreled probe provided adequate measurements via both its steady state and high response tubes (within +/- 0.15 percent accuracy) over unacceptable ranges of biased pitch and inconsistent yaw angles which varied with Mach number. By comparison, the coannular probe provided accurate measurements (at zero incidence) for all jet Mach numbers as well as over a flow angularity range which varied from +/- 26.0 deg at Mach 0.3 deg to +/- 14.0 deg at Mach 0.9. Based on these results, the Prati probe is established as the preferred design. Further experimental tests are recommended to document the frequency response characteristics of the Prati probe.

  1. Chemical Probes of Rapid Estrogen Signaling in Breast Cancer Treatment and Chemoprevention

    Science.gov (United States)

    2007-04-01

    The analogs will also be conju- gated to cell-impermeable polyacrylate polymers that should allow for selective targeting of membrane-initiated...the GW7604 analogs. Briefly, serial dilutions of the different compounds were prepared in ES2 screening buffer (100 mM potassium phosphate, pH7.4, 100...AD_________________ Award Number: W81XWH-04-1-0447 TITLE: CHEMICAL PROBES OF RAPID ESTROGEN

  2. Detection of Fatigue Cracks at Rivets with Self-Nulling Probe

    Science.gov (United States)

    Wincheski, Buzz; Fulton, Jim; Nath, Shridhar; Namkung, Min

    1994-01-01

    A new eddy current probe developed at NASA Langley Research Center has been used to detect small cracks at rivets in aircraft lap splices [1]. The device has earlier been used to detect isolated fatigue cracks with a minimum detectable flaw size of roughly 1/2 to 1/3 the diameter of the probe [2]. The present work shows that the detectable flaw size for cracks originating at rivets can be greatly improved upon from that of isolated flaws. The use of a rotating probe method combined with spatial filtering has been used to detect 0.18 cm EDM notches, as measured from the rivet shank, with a 1.27 cm diameter probe and to detect flaws buried under the rivet head, down to a length of 0.076 cm, using a 0.32 cm diameter probe. The Self-Nulling Electromagnetic Flaw Detector induces a high density eddy current ring in the sample under test. A ferromagnetic flux focusing lens is incorporated such that in the absence of any inhomogeneities in the material under test only a minimal magnetic field will reach the interior of the probe. A magnetometer (pickup coil) located in the center of the probe therefore registers a null voltage in the absence of material defects. When a fatigue crack or other discontinuity is present in the test article the path of the eddy currents in the material is changed. The magnetic field associated with these eddy currents then enter into the interior of the probe, producing a large output voltage across the pickup coil leads. Further

  3. Stress-Corrosion Cracking in Martensitic PH Stainless Steels

    Science.gov (United States)

    Humphries, T.; Nelson, E.

    1984-01-01

    Precipitation-hardening alloys evaluated in marine environment tests. Report describes marine-environment stress-corrosion cracking (SCC) tests of three martensitic precipitation hardening (PH) stainless-steel alloys.

  4. Ex vivo Porcine Model to Measure pH Dependence of gagCEST in the Inter-Vertebral Disc

    Science.gov (United States)

    Melkus, Gerd; Grabau, Michelle; Karampinos, Dimitrios C.; Majumdar, Sharmila

    2013-01-01

    Purpose Studies have linked low pH and loss of glycosaminoglycan (GAG) in the intervertebral discs (IVDs) of patients with discogenic back pain. The purpose of the present study is to determine whether the chemical exchange saturation transfer (CEST) effect of GAG (gagCEST) is pH-dependent and whether it can be used to detect pH changes in IVD specimens. Iopromide, a FDA approved agent for CT/X-Ray, was also evaluated as a pH-sensitive CEST probe to explore the agents’ potential to measure IVD pH. Methods The pH dependency of the CEST effect of chondroitin sulfate (containing GAG) and Iopromide phantoms was investigated at 7 T. Z-spectra from porcine IVD specimens were acquired before and after manipulating the pH with sodium lactate. Iopromide was injected into the specimens and the calibration curve was used to determine the pH status. Results Chondroitin sulfate showed a non-linear dependence of gagCEST effect with pH and gagCEST signal differences were detected in the specimens. The CEST effect of Iopromide resulted in a sigmoidal relation with pH and was used to measure pH. Conclusion gagCEST is sensitive to pH and enables investigation of the IVD pH status. Iopromide CEST is independent of the local GAG concentration and has the potential for measuring pH in the IVD. PMID:23818244

  5. Sensing H+ with conventional neural probes

    International Nuclear Information System (INIS)

    Trantidou, T.; Tsiligkiridis, V.; Chang, Y.-C.; Toumazou, C.; Prodromakis, T.

    2013-01-01

    In this paper, we demonstrate a technique for transforming commercially available neural probes used for electrical recordings, into chemical sensing devices for detection of ionic concentrations in electrolytes, with particular emphasis to pH. This transformation requires a single post-processing step to incorporate a thin indium tin oxide membrane for sensing H + . Measured results indicate a chemical sensitivity of 28 mV/pH, and relatively low leakage currents (2–10 nA) and drifts (1–10 mV/h). The proposed sensing device demonstrates the possibility of a low-cost implementation that can be reusable and thus versatile, with potential applications in real-time extracellular but mainly intracellular chemical monitoring.

  6. Fabrication of tungsten probe for hard tapping operation in atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Han, Guebum, E-mail: hanguebum@live.co.kr [Department of Physics and Optical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, Indiana 47803 (United States); Department of Mechanical Design and Robot Engineering, Seoul National University of Science and Technology, 232 Gongneung-ro, Nowon-gu, Seoul 139-743 (Korea, Republic of); Ahn, Hyo-Sok, E-mail: hsahn@seoultech.ac.kr [Manufacturing Systems and Design Engineering Programme, Seoul National University of Science & Technology, 232 Gongneung-ro, Nowon-gu, Seoul 139-743 (Korea, Republic of)

    2016-02-15

    We propose a method of producing a tungsten probe with high stiffness for atomic force microscopy (AFM) in order to acquire enhanced phase contrast images and efficiently perform lithography. A tungsten probe with a tip radius between 20 nm and 50 nm was fabricated using electrochemical etching optimized by applying pulse waves at different voltages. The spring constant of the tungsten probe was determined by finite element analysis (FEA), and its applicability as an AFM probe was evaluated by obtaining topography and phase contrast images of a Si wafer sample partly coated with Au. Enhanced hard tapping performance of the tungsten probe compared with a commercial Si probe was confirmed by conducting hard tapping tests at five different oscillation amplitudes on single layer graphene grown by chemical vapor deposition (CVD). To analyze the damaged graphene sample, the test areas were investigated using tip-enhanced Raman spectroscopy (TERS). The test results demonstrate that the tungsten probe with high stiffness was capable of inducing sufficient elastic and plastic deformation to enable obtaining enhanced phase contrast images and performing lithography, respectively. - Highlights: • We propose a method of producing highly stiff tungsten probes for hard tapping AFM. • Spring constant of tungsten probe is determined by finite element method. • Enhanced hard tapping performance is confirmed. • Tip-enhanced Raman spectroscopy is used to identify damage to graphene.

  7. Fabrication of tungsten probe for hard tapping operation in atomic force microscopy

    International Nuclear Information System (INIS)

    Han, Guebum; Ahn, Hyo-Sok

    2016-01-01

    We propose a method of producing a tungsten probe with high stiffness for atomic force microscopy (AFM) in order to acquire enhanced phase contrast images and efficiently perform lithography. A tungsten probe with a tip radius between 20 nm and 50 nm was fabricated using electrochemical etching optimized by applying pulse waves at different voltages. The spring constant of the tungsten probe was determined by finite element analysis (FEA), and its applicability as an AFM probe was evaluated by obtaining topography and phase contrast images of a Si wafer sample partly coated with Au. Enhanced hard tapping performance of the tungsten probe compared with a commercial Si probe was confirmed by conducting hard tapping tests at five different oscillation amplitudes on single layer graphene grown by chemical vapor deposition (CVD). To analyze the damaged graphene sample, the test areas were investigated using tip-enhanced Raman spectroscopy (TERS). The test results demonstrate that the tungsten probe with high stiffness was capable of inducing sufficient elastic and plastic deformation to enable obtaining enhanced phase contrast images and performing lithography, respectively. - Highlights: • We propose a method of producing highly stiff tungsten probes for hard tapping AFM. • Spring constant of tungsten probe is determined by finite element method. • Enhanced hard tapping performance is confirmed. • Tip-enhanced Raman spectroscopy is used to identify damage to graphene.

  8. Evaluation of mitochondrial activity by two-photon absorption with near-field multioptical fiber probes

    Science.gov (United States)

    Kanazashi, Yasuaki; Takara, Naoshi; Iwami, Kentaro; Ohta, Yoshihiro; Umeda, Norihiro

    2018-04-01

    pH measurements enable the direct monitoring and evaluation of mitochondrial activity. We constructed a scanning near-field optical microscopy system with multioptical fiber probes using the two-photon absorption of a pH-sensitive fluorescent dye, SNARF-4F, to measure the activity difference of mitochondrial aggregates. pH can be monitored through the fluorescence intensity ratio (FIR) of SNARF-4F. We derived a calibration curve of the FIR as a function of pH. The FIR dynamic responses were measured by adding hydrochloric acid to the buffer solution. Using the developed system, we simultaneously measured the pH changes at two different locations in the SNARF-4F solution. Mitochondrial samples were prepared using optical tweezers to control the number and position of mitochondria. Mitochondrial pH changes (ΔpH) between 0.05 and 0.57 were observed after adding a nutritional supplement (malate and glutamate). In addition, in the comparative experiment on the activities of two mitochondrial populations, the obtained result suggested that the activity differs depending on the difference in the number of mitochondria.

  9. Intraoral pH and temperature during sleep with and without mouth breathing.

    Science.gov (United States)

    Choi, J E; Waddell, J N; Lyons, K M; Kieser, J A

    2016-05-01

    To measure and compare the intraoral pH and temperature of individuals during sleep with and without mouth breathing. Ten healthy participants [mean age = 25·8 (± 4·3)] wore a custom-made appliance fitted with a pH probe and thermocouple for two sets of 48 h. Continuous pH and temperature measurements were taken from the palatal aspect of the upper central incisors. To simulate mouth breathing during sleep, participants wore a nose clip for two nights of the four, with the first group (n = 5) wearing the nose clip during the first night and the rest (n = 5) wearing the nose clip during the second night of sleep to balance any potential bias from the wearing sequence. Both qualitative and quantitative analyses were conducted. The mean intraoral pH during daytime was 7·3 (± 0·4) and during sleep was 7·0 (± 0·5). The mean intraoral pH during sleep with mouth breathing was 6·6 (± 0·5), which was statistically significant compared with the normal sleep condition (P pH decreased slowly over the hours of sleep in all participants. When sleeping with forced mouth breathing, intraoral pH showed a greater fall over a longer period of time. The mean intraoral temperature was 33·1 °C (± 5·2) during daytime and 33·3 °C (± 6·1) during sleep, with no statistical significance between sleep with and without mouth breathing (P > 0·05). The results suggest that mouth breathing during sleep is related to a decrease in intraoral pH compared with normal breathing during sleep, and this has been proposed as a causal factor for dental erosion and caries. © 2015 John Wiley & Sons Ltd.

  10. Imaging of Intracellular pH in Tumor Spheroids Using Genetically Encoded Sensor SypHer2.

    Science.gov (United States)

    Zagaynova, Elena V; Druzhkova, Irina N; Mishina, Natalia M; Ignatova, Nadezhda I; Dudenkova, Varvara V; Shirmanova, Marina V

    2017-01-01

    Intracellular pH (pHi) is one of the most important parameters that regulate the physiological state of cells and tissues. pHi homeostasis is crucial for normal cell functioning. Cancer cells are characterized by having a higher (neutral to slightly alkaline) pHi and lower (acidic) extracellular pH (pHe) compared to normal cells. This is referred to as a "reversed" pH gradient, and is essential in supporting their accelerated growth rate, invasion and migration, and in suppressing anti-tumor immunity, the promotion of metabolic coupling with fibroblasts and in preventing apoptosis. Moreover, abnormal pH, both pHi and pHe, contribute to drug resistance in cancers. Therefore, the development of methods for measuring pH in living tumor cells is likely to lead to better understanding of tumor biology and to open new ways for cancer treatment. Genetically encoded, fluorescent, pH-sensitive probes represent promising instruments enabling the subcellular measurement of pHi with unrivaled specificity and high accuracy. Here, we describe a protocol for pHi imaging at a microscopic level in HeLa tumor spheroids, using the genetically encoded ratiometric (dual-excitation) pHi indicator, SypHer2.

  11. A New Probe for Mechanical Testing of Nanostructures in Soft Materials

    International Nuclear Information System (INIS)

    Hough, L.A.; Ou-Yang, H.D.

    1999-01-01

    We report a new application of the optical tweezers, where a harmonically driven oscillating tweezer is combined with the forward light scattering and lock-in amplification techniques, for probing the mechanics of nanostructures in soft materials in a broad frequency range. Model independent dynamic moduli G' and G'' of the material at a localized, sub-micron area can be measured directly from the displacement and the phase shift of the particle in the oscillating trap. The probe particles can be as small as 200 nm and the displacement of the particle was in the range of a few nanometers. To illustrate the new methodology, we show the microscopic viscoelastic properties of a transient polymer network in the vicinity of a silica bead

  12. Hydrazine selective dual signaling chemodosimetric probe in physiological conditions and its application in live cells

    Energy Technology Data Exchange (ETDEWEB)

    Nandi, Sandip; Sahana, Animesh; Mandal, Sandip [Department of Chemistry, The University of Burdwan, Burdwan, 713104 West Bengal (India); Sengupta, Archya; Chatterjee, Ansuman [Department of Zoology, Visva Bharati University, Santiniketan, West Bengal (India); Safin, Damir A., E-mail: damir.a.safin@gmail.com [Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve (Belgium); Babashkina, Maria G.; Tumanov, Nikolay A.; Filinchuk, Yaroslav [Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université catholique de Louvain, Place L. Pasteur 1, 1348 Louvain-la-Neuve (Belgium); Das, Debasis, E-mail: ddas100in@yahoo.com [Department of Chemistry, The University of Burdwan, Burdwan, 713104 West Bengal (India)

    2015-09-17

    A rhodamine–cyanobenzene conjugate, (E)-4-((2-(3′,6′-bis(diethylamino)-3-oxospiro[isoindoline-1,9′-xanthene] -2-yl)ethylimino)methyl)benzonitrile (1), which structure has been elucidated by single crystal X-ray diffraction, was synthesized for selective fluorescent “turn-on” and colorimetric recognition of hydrazine at physiological pH 7.4. It was established that 1 detects hydrazine up to 58 nM. The probe is useful for the detection of intracellular hydrazine in the human breast cancer cells MCF-7 using a fluorescence microscope. Spirolactam ring opening of 1, followed by its hydrolysis, was established as a probable mechanism for the selective sensing of hydrazine. - Highlights: • A selective rhodamine–cyanobenzene conjugate is synthesized. • The conjugate is a selective dual signaling chemodosimetric probe towards hydrazine. • Spirolactam ring opening of the probe, followed by its hydrolysis, is the sensing mechanism. • The probe detects hydrazine in the human breast cancer cells MCF-7 imaging.

  13. Evaluation of Flat Surface Temperature Probes

    Science.gov (United States)

    Beges, G.; Rudman, M.; Drnovsek, J.

    2011-01-01

    The objective of this paper is elaboration of elements related to metrological analysis in the field of surface temperature measurement. Surface temperature measurements are applicable in many fields. As examples, safety testing of electrical appliances and a pharmaceutical production line represent case studies for surface temperature measurements. In both cases correctness of the result of the surface temperature has an influence on final product safety and quality and thus conformity with specifications. This paper deals with the differences of flat surface temperature probes in measuring the surface temperature. For the purpose of safety testing of electrical appliances, surface temperature measurements are very important for safety of the user. General requirements are presented in European standards, which support requirements in European directives, e.g., European Low Voltage Directive 2006/95/EC and pharmaceutical requirements, which are introduced in official state legislation. This paper introduces a comparison of temperature measurements of an attached thermocouple on the measured surface and measurement with flat surface temperature probes. As a heat generator, a so called temperature artifact is used. It consists of an aluminum plate with an incorporated electrical heating element with very good temperature stability in the central part. The probes and thermocouple were applied with different forces to the surface in horizontal and vertical positions. The reference temperature was measured by a J-type fine-wire (0.2 mm) thermocouple. Two probes were homemade according to requirements in the European standard EN 60335-2-9/A12, one with a fine-wire (0.2 mm) thermocouple and one with 0.5mm of thermocouple wire diameter. Additional commercially available probes were compared. Differences between probes due to thermal conditions caused by application of the probe were found. Therefore, it can happen that measurements are performed with improper equipment or

  14. In situ Probe Microphone Measurement for Testing the Direct Acoustical Cochlear Stimulator

    Directory of Open Access Journals (Sweden)

    Christof Stieger

    2017-08-01

    Full Text Available Hypothesis: Acoustical measurements can be used for functional control of a direct acoustic cochlear stimulator (DACS.Background: The DACS is a recently released active hearing implant that works on the principle of a conventional piston prosthesis driven by the rod of an electromagnetic actuator. An inherent part of the DACS actuator is a thin titanium diaphragm that allows for movement of the stimulation rod while hermetically sealing the housing. In addition to mechanical stimulation, the actuator emits sound into the mastoid cavity because of the motion of the diaphragm.Methods: We investigated the use of the sound emission of a DACS for intra-operative testing. We measured sound emission in the external auditory canal (PEAC and velocity of the actuators stimulation rod (Vact in five implanted ears of whole-head specimens. We tested the influence various positions of the loudspeaker and a probe microphone on PEAC and simulated implant malfunction in one example.Results: Sound emission of the DACS with a signal-to-noise ratio >10 dB was observed between 0.5 and 5 kHz. Simulated implant misplacement or malfunction could be detected by the absence or shift in the characteristic resonance frequency of the actuator. PEAC changed by <6 dB for variations of the microphone and loudspeaker position.Conclusion: Our data support the feasibility of acoustical measurements for in situ testing of the DACS implant in the mastoid cavity as well as for post-operative monitoring of actuator function.

  15. Millimeter/submillimeter spectroscopy of PH{sub 2}CN ( X-tilde {sup 1}A') and CH{sub 3}PH{sub 2} ( X-tilde {sup 1}A'): probing the complexity of interstellar phosphorus chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Halfen, D. T.; Ziurys, L. M. [Department of Chemistry and Biochemistry, Department of Astronomy, Arizona Radio Observatory, and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Clouthier, D. J., E-mail: halfendt@as.arizona.edu [Department of Chemistry, University of Kentucky, Lexington, KY 40506 (United States)

    2014-11-20

    Millimeter/submillimeter spectra of PH{sub 2}CN ( X-tilde {sup 1}A') and CH{sub 3}PH{sub 2} ( X-tilde {sup 1}A') have been recorded for the first time using direct absorption techniques. This work extends previous measurements of both molecules beyond the 10-50 GHz range. Both species were created in the presence of an AC discharge by the reaction of phosphorus vapor and either cyanogen and hydrogen (PH{sub 2}CN) or methane (CH{sub 3}PH{sub 2}). Twelve rotational transitions of PH{sub 2}CN were recorded over the region 305-422 GHz for asymmetry components K{sub a} = 0 through 8. For CH{sub 3}PH{sub 2}, eight rotational transitions were measured from 210-470 GHz with K{sub a} = 0 through 16; these spectra exhibited greater complexity due to the presence of internal rotation, which splits the K{sub a} = 1, 2, and 3 asymmetry components into A and E states. Combined analyses of the millimeter/submillimeter and previous microwave data were performed for both molecules. For PH{sub 2}CN, the spectra were fit with a Watson S-reduced asymmetric top Hamiltonian, resulting in more accurate rotational and centrifugal distortion constants. In the case of CH{sub 3}PH{sub 2}, an asymmetric top internal-rotation Hamiltonian was employed in the analysis, significantly improving the rotational and torsional parameters over previous microwave estimates. Searches for both molecules were subsequently conducted toward Sgr B2(N), using the 12 m telescope of the Arizona Radio Observatory (ARO). Neither species was identified, with abundance upper limits, relative to H{sub 2}, of f (PH{sub 2}CN/H{sub 2}) < 7.0 × 10{sup –12} and f (CH{sub 3}PH{sub 2}/H{sub 2}) < 8.4 × 10{sup –12}. The nitrogen analogs NH{sub 2}CN and CH{sub 3}NH{sub 2} are therefore more abundant in Sgr B2(N) by factors of >2 and >200, respectively.

  16. Cell wall pH and auxin transport velocity

    Science.gov (United States)

    Hasenstein, K. H.; Rayle, D.

    1984-01-01

    According to the chemiosmotic polar diffusion hypothesis, auxin pulse velocity and basal secretion should increase with decreasing cell wall pH. Experiments were designed to test this prediction. Avena coleoptile sections were preincubated in either fusicoccin (FC), cycloheximide, pH 4.0, or pH 8.0 buffer and subsequently their polar transport capacities were determined. Relative to controls, FC enhanced auxin (IAA) uptake while CHI and pH 8.0 buffer reduced IAA uptake. Nevertheless, FC reduced IAA pulse velocity while cycloheximide increased velocity. Additional experiments showed that delivery of auxin to receivers is enhanced by increased receiver pH. This phenomenon was overcome by a pretreatment of the tissue with IAA. Our data suggest that while acidic wall pH values facilitate cellular IAA uptake, they do not enhance pulse velocity or basal secretion. These findings are inconsistent with the chemiosmotic hypothesis for auxin transport.

  17. Probes for edge plasma studies of TFTR (invited)

    International Nuclear Information System (INIS)

    Manos, D.M.; Budny, R.V.; Kilpatrick, S.; Stangeby, P.; Zweben, S.

    1986-01-01

    Tokamak fusion test reactor (TFTR) probes are designed to study the interaction of the plasma with material surfaces such as the wall and limiters, and to study the transport of particles and energy between the core and edge. Present probe heads have evolved from prototypes in Princeton large torus (PLT), poloidal divertor experiment (PDX) [Princeton BETA experiment (PBX)], and the initial phase of TFTR operation. The newest heads are capable of making several simultaneous measurements and include Langmuir probes, heat flux probes, magnetic coils, rotating calorimeter fast ion probes, and sample exposure specimens. This paper describes these probe heads and presents some of the data they and their prototypes have acquired. The paper emphasizes measurement of transient plasma effects such as fast ion loss during auxiliary heating, the evolution of the edge plasma during heating, compression, and free expansion, and fluctuations in the edge plasma

  18. Salivary pH: A diagnostic biomarker

    OpenAIRE

    Baliga, Sharmila; Muglikar, Sangeeta; Kale, Rahul

    2013-01-01

    Objectives: Saliva contains a variety of host defense factors. It influences calculus formation and periodontal disease. Different studies have been done to find exact correlation of salivary biomarkers with periodontal disease. With a multitude of biomarkers and complexities in their determination, the salivary pH may be tried to be used as a quick chairside test. The aim of this study was to analyze the pH of saliva and determine its relevance to the severity of periodontal disease. Study D...

  19. Recurrent symptoms after fundoplication with a negative pH study--recurrent reflux or functional heartburn?

    Science.gov (United States)

    Thompson, Sarah K; Cai, Wang; Jamieson, Glyn G; Zhang, Alison Y; Myers, Jennifer C; Parr, Zoe E; Watson, David I; Persson, Jenny; Holtmann, Gerald; Devitt, Peter G

    2009-01-01

    A small cohort of patients present after antireflux surgery complaining of recurrent heartburn. Over two thirds of these patients will have a negative 24-h pH study. The aim of our study is to determine whether these patients have an associated functional disorder or abnormal cytokine activity and to examine the reproducibility of pH testing. A prospective analysis was carried out on a cohort of patients who had undergone a fundoplication and postoperative pH testing for recurrent heartburn: group A--patients with recurrent heartburn and a negative 24-h pH study and group B (control group)--patients with recurrent heartburn and a positive pH study. Questionnaires, a blood sample, and repeat pH testing were completed. Sixty-nine patients were identified. Group A's depression score (8.6 +/- 4.1) was significantly higher than group B's (5.9 +/- 4.2; P = 0.03). Cytokine levels were similar in both groups. Forty-seven of 49 (96%) patients who underwent repeat pH testing had a negative study. Symptom-reflux correlation was highly significant (P heartburn and a negative pH study have associated functional or psychiatric comorbidities such as depression. Reproducibility of 24-h pH testing in these patients is excellent.

  20. Evaluating high pH for control of dreissenid mussels

    OpenAIRE

    Dave Evans; Sergey E. Mastitsky; Katherine L. Prescott; Thomas H. Prescott; Renata Claudi; Anna Carolina Taraborelli

    2013-01-01

    Two field experiments were carried out using a custom built flow-through laboratory to test the effect of elevated pH on dreissenid musselsas a potential control method. Both experiments tested the ability of dreissenid pediveligers to settle under conditions of elevated pH and thelong-term survival of adult dreissenids under the same conditions. The two experimental sites had different water quality and differentspecies of dreissenids present. The settlement of quagga mussel pediveligers at ...

  1. Effects of Mach number on pitot-probe displacement in a turbulent boundary layer

    Science.gov (United States)

    Allen, J. M.

    1974-01-01

    Experimental pitot-probe-displacement data have been obtained in a turbulent boundary layer at a local free-stream Mach number of 4.63 and unit Reynolds number of 6.46 million meter. The results of this study were compared with lower Mach number results of previous studies. It was found that small probes showed displacement only, whereas the larger probes showed not only displacement but also distortion of the shape of the boundary-layer profile. The distortion pattern occurred lower in the boundary layer at the higher Mach number than at the the lower Mach number. The maximum distortion occurred when the center of the probe was about one probe diameter off the test surface. For probes in the wall contact position, the indicated Mach numbers were, for all probes tested, close to the true profile. Pitot-probe displacement was found to increase significantly with increasing Mach number.

  2. In Vivo Monitoring of pH, Redox Status, and Glutathione Using L-Band EPR for Assessment of Therapeutic Effectiveness in Solid Tumors

    Science.gov (United States)

    Bobko, Andrey A.; Eubank, Timothy D.; Voorhees, Jeffrey L.; Efimova, Olga V.; Kirilyuk, Igor A.; Petryakov, Sergey; Trofimiov, Dmitrii G.; Marsh, Clay B.; Zweier, Jay L.; Grigor’ev, Igor A.; Samouilov, Alexandre; Khramtsov, Valery V.

    2011-01-01

    Approach for in vivo real-time assessment of tumor tissue extracellular pH (pHe), redox, and intracellular glutathione based on L-band EPR spectroscopy using dual function pH and redox nitroxide probe and disulfide nitroxide biradical, is described. These parameters were monitored in PyMT mice bearing breast cancer tumors during treatment with granulocyte macrophage colony-stimulating factor. It was observed that tumor pHe is about 0.4 pH units lower than that in normal mammary gland tissue. Treatment with granulocyte macrophage colony-stimulating factor decreased the value of pHe by 0.3 units compared with PBS control treatment. Tumor tissue reducing capacity and intracellular glutathione were elevated compared with normal mammary gland tissue. Granulocyte macrophage colony-stimulating factor treatment resulted in a decrease of the tumor tissue reducing capacity and intracellular glutathione content. In addition to spectroscopic studies, pHe mapping was performed using recently proposed variable frequency proton–electron double-resonance imaging. The pH mapping superimposed with MRI image supports probe localization in mammary gland/tumor tissue, shows high heterogeneity of tumor tissue pHe and a difference of about 0.4 pH units between average pHe values in tumor and normal mammary gland. In summary, the developed multifunctional approach allows for in vivo, noninvasive pHe, extracellular redox, and intracellular glutathione content monitoring during investigation of various therapeutic strategies for solid tumors. Magn Reson Med 000:000–000, 2011. PMID:22113626

  3. Temperature and pH sensors based on graphenic materials.

    Science.gov (United States)

    Salvo, P; Calisi, N; Melai, B; Cortigiani, B; Mannini, M; Caneschi, A; Lorenzetti, G; Paoletti, C; Lomonaco, T; Paolicchi, A; Scataglini, I; Dini, V; Romanelli, M; Fuoco, R; Di Francesco, F

    2017-05-15

    Point-of-care applications and patients' real-time monitoring outside a clinical setting would require disposable and durable sensors to provide better therapies and quality of life for patients. This paper describes the fabrication and performances of a temperature and a pH sensor on a biocompatible and wearable board for healthcare applications. The temperature sensor was based on a reduced graphene oxide (rGO) layer that changed its electrical resistivity with the temperature. When tested in a human serum sample between 25 and 43°C, the sensor had a sensitivity of 110±10Ω/°C and an error of 0.4±0.1°C compared with the reference value set in a thermostatic bath. The pH sensor, based on a graphene oxide (GO) sensitive layer, had a sensitivity of 40±4mV/pH in the pH range between 4 and 10. Five sensor prototypes were tested in a human serum sample over one week and the maximum deviation of the average response from reference values obtained by a glass electrode was 0.2pH units. For biological applications, the temperature and pH sensors were successfully tested for in vitro cytotoxicity with human fibroblast cells (MRC-5) over 24h. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Probe for detection of denting in PWR steam generator tubes

    International Nuclear Information System (INIS)

    Gerardin, J.P.; Germain, J.L.; Nio, J.C.

    1994-07-01

    In certain types of PWR steam generator, oxide deposits can lead to embedding, and subsequently to deformation of a tube (the phenomenon of ''denting''). Such embedding changes the vibratory behavior of the tubes and can result in fatigue cracking. This type of cracking can also be worsened in the event of improper assembly of the anti-vibration spacer bars supporting the U-bends. To prevent such incidents and provide for effective preventive condition-directed maintenance of its PWR steam generators, EDF has undertaken the study and development of a probe to detect this type of phenomenon. The studies began in 1990 and led to the building of an initial prototype probe. The principle behind the probe consists in inducing vibration in the U-bend and determining the main resonance modes of the tube. Measurements of frequency and amplitude and calculation of damping enable characterization of the mechanical behavior of the U-bend. The most important parameter is damping, for which the value must be sufficiently high to ensure that the tube is not subjected to major vibratory amplitudes during operation. Numerous tests have been performed with the first prototype version of the probe, on a mock-up in the test area and on one of the demounted steam generators on the Dampierre site. These different tests have enabled validation of the operating principle, fine-tuning the process, pinpointing certain mechanical problems in the probe design, and obtaining the first indications as to the real vibratory behavior of U-bends on a steam generator. On the basis of these preliminary tests, the specifications were drawn up for an industrial version of the probe. Following a call for bids and the choice of a manufacturer, work began on fabrication of a new probe model in 1993. This version was delivered at the end of 1993 and testing began in 1994. (authors). 5 figs., 2 tabs

  5. Imaging optical probe for pressurized 6200K steam-water environment

    International Nuclear Information System (INIS)

    Donaldson, M.R.; Pulfrey, R.E.; Merrill, S.K.

    1979-01-01

    An air-cooled imaging optical probe, 0.3 m long with a 25.4-mm outside diameter, has been built to provide high resolution viewing of flow regimes in a steam-water environment at 620 0 K and 15.5 MPa. The probe consists of a 3.5-mm-diameter rod lens borescope, surrounded by two coaxial coolant flow channels and two coaxial insulating dead air spaces. With air flowing through the probe at 5.7 g/s, thermal analysis shows that no part of the optical borescope will exceed 366 0 K when the probe is immersed in a 620 0 K environment. The objective lens is protected by a sapphire window which tests have shown can survive over 200 hours in 620 0 K water or steam with negligible loss of resolution and contrast. Condensation on the protective window is boiled off by electrically heating the window. Computer stress analysis, plus actual tests, shows that the probe can operate successfully with conservative safety factors

  6. Comparison of pulse characteristic of low frequency ultrasonic probes for concrete application

    International Nuclear Information System (INIS)

    Amry Amin Abas; Suhairy Sani; Muhammad Pauzi Ismail

    2006-01-01

    Ultrasonic testing of concrete or large volume of composites usually is done in low frequency range. To obtain low frequency pulse, a low frequency pulser/receiver is used attached to a low frequency probe as transmitter/receiver. Concrete is highly attenuative and a high energy pulse is essential to ensure good penetration of test samples. High energy pulse can be obtained by producing low frequency ultrasonic waves.To achieve high penetration in concrete, a low frequency probe is fabricated with the centre frequency lying at around 100 kHz. The probe is fabricated with single crystal of 18 mm thickness without any backing material to obtain wider pulse and higher pulse power. Then, comparison of pulse characteristic is done between the fabricated probe and a commercially available probe to determine the quality of the probe fabricated. (Author)

  7. An effective colorimetric and ratiometric fluorescent probe for bisulfite in aqueous solution

    International Nuclear Information System (INIS)

    Dai, Xi; Zhang, Tao; Du, Zhi-Fang; Cao, Xiang-Jian; Chen, Ming-Yu; Hu, Sheng-Wen; Miao, Jun-Ying; Zhao, Bao-Xiang

    2015-01-01

    We have developed the first two-photon colorimetric and ratiometric fluorescent probe, BICO, for the detection of bisulfite (HSO 3 − ) in aqueous solution. The probe contains coumarin and benzimidazole moieties and can detect HSO 3 − based on the Michael addition reaction with a limit of detection 5.3 × 10 −8  M in phosphate-buffered saline solution. The probe was used to detect bisulfite in tap water, sugar and dry white wine. Moreover, test strips were made and used easily. We successfully applied the probe to image living cells, using one-photon fluorescence imaging. BICO overcomes the limitations in sensitivity of previously reported probes and the solvation effect of bisulfite, which demonstrates its excellent value in practical application. - Highlights: • A colorimetric and ratiometric fluorescent probe was developed. • The probe could detect bisulfite in PBS buffer solution and real samples. • Bisulfite test paper was made to naked-eye detect bisulfite. • This probe successfully used to living cell imaging in ratiometric manner

  8. An effective colorimetric and ratiometric fluorescent probe for bisulfite in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Xi [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Zhang, Tao [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Du, Zhi-Fang; Cao, Xiang-Jian; Chen, Ming-Yu [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Taishan College, Shandong University, Jinan 250100 (China); Hu, Sheng-Wen [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Miao, Jun-Ying, E-mail: miaojy@sdu.edu.cn [Institute of Developmental Biology, School of Life Science, Shandong University, Jinan 250100 (China); Zhao, Bao-Xiang, E-mail: bxzhao@sdu.edu.cn [Institute of Organic Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2015-08-12

    We have developed the first two-photon colorimetric and ratiometric fluorescent probe, BICO, for the detection of bisulfite (HSO{sub 3}{sup −}) in aqueous solution. The probe contains coumarin and benzimidazole moieties and can detect HSO{sub 3}{sup −} based on the Michael addition reaction with a limit of detection 5.3 × 10{sup −8} M in phosphate-buffered saline solution. The probe was used to detect bisulfite in tap water, sugar and dry white wine. Moreover, test strips were made and used easily. We successfully applied the probe to image living cells, using one-photon fluorescence imaging. BICO overcomes the limitations in sensitivity of previously reported probes and the solvation effect of bisulfite, which demonstrates its excellent value in practical application. - Highlights: • A colorimetric and ratiometric fluorescent probe was developed. • The probe could detect bisulfite in PBS buffer solution and real samples. • Bisulfite test paper was made to naked-eye detect bisulfite. • This probe successfully used to living cell imaging in ratiometric manner.

  9. Chronic effect of low pH on fathead minnow survival, growth, and reproduction

    Energy Technology Data Exchange (ETDEWEB)

    Mount, D I

    1973-01-01

    Fathead minnows (Pimephales promelas rafinesque) were continuously exposed to reduced pH levels of 4.5, 5.2, 5.9, 6.6, and 7.5 (control) during a 13-month, one-generation test. Survival was not affected, even at the lowest pH tested. Fish behavior was abnormal, and fish were deformed at pH 4.5 and 5.2. Egg production and egg hatchability were reduced at pH 5.9 and lower, and all eggs were abnormal. A pH of 6.6 was marginal for vital life functions, but safe for continuous exposure. Free carbon dioxide, liberated by the addition of sulfuric acid to reduce the pH, may have had an unknown effect. The fish did not become acclimiated to low pH levels.

  10. Optic nerve pH and PO2

    DEFF Research Database (Denmark)

    Pedersen, Daniella B; Stefánsson, Einar; Kiilgaard, Jens Folke

    2006-01-01

    Earlier studies have demonstrated that carbonic anhydrase inhibitors (CAIs) increase optic nerve oxygen tension (ONPO(2)) in pigs. We hypothesized that the mechanism of this effect was either a CO(2) increase or a pH decrease in tissue and blood. To test this hypothesis we investigated and compared...... how optic nerve pH (ONpH) and ONPO(2) are affected by: (1) carbonic anhydrase inhibition; (2) respiratory acidosis, and (3) metabolic acidosis. We measured ONpH with a glass pH electrode and ONPO(2) with a polarographic oxygen electrode. One of the electrodes was placed in the vitreous cavity 0.5 mm...

  11. Numerical modeling of probe velocity effects for electromagnetic NDE methods

    Science.gov (United States)

    Shin, Y. K.; Lord, W.

    The present discussion of magnetic flux (MLF) leakage inspection introduces the behavior of motion-induced currents. The results obtained indicate that velocity effects exist at even low probe speeds for magnetic materials, compelling the inclusion of velocity effects in MLF testing of oil pipelines, where the excitation level and pig speed are much higher than those used in the present work. Probe velocity effect studies should influence probe design, defining suitable probe speed limits and establishing training guidelines for defect-characterization schemes.

  12. Design and performance verification of a wideband scalable dual-polarized probe for spherical near-field antenna measurements

    DEFF Research Database (Denmark)

    Pivnenko, Sergey; Kim, Oleksiy S.; Nielsen, Jeppe Majlund

    2012-01-01

    A wideband scalable dual-polarized probe designed by the Electromagnetic Systems group at the Technical University of Denmark is presented. The design was scaled and two probes were manufactured for the frequency bands 1-3 GHz and 0.4-1.2 GHz. The results of the acceptance tests of the 0.4-1.2 GHz...... probe are briefly discussed. Since these probes represent so-called higher-order antennas, applicability of the recently developed higher-order probe correction technique [3] for these probes was investigated. Extensive tests were carried out for two representative antennas under test using...

  13. Flight calibration of compensated and uncompensated pitot-static airspeed probes and application of the probes to supersonic cruise vehicles

    Science.gov (United States)

    Webb, L. D.; Washington, H. P.

    1972-01-01

    Static pressure position error calibrations for a compensated and an uncompensated XB-70 nose boom pitot static probe were obtained in flight. The methods (Pacer, acceleration-deceleration, and total temperature) used to obtain the position errors over a Mach number range from 0.5 to 3.0 and an altitude range from 25,000 feet to 70,000 feet are discussed. The error calibrations are compared with the position error determined from wind tunnel tests, theoretical analysis, and a standard NACA pitot static probe. Factors which influence position errors, such as angle of attack, Reynolds number, probe tip geometry, static orifice location, and probe shape, are discussed. Also included are examples showing how the uncertainties caused by position errors can affect the inlet controls and vertical altitude separation of a supersonic transport.

  14. An excited-state intramolecular photon transfer fluorescence probe for localizable live cell imaging of cysteine

    Science.gov (United States)

    Liu, Wei; Chen, Wen; Liu, Si-Jia; Jiang, Jian-Hui

    2017-03-01

    Small molecule probes suitable for selective and specific fluorescence imaging of some important but low-concentration intracellular reactive sulfur species such as cysteine (Cys) pose a challenge in chemical biology. We present a readily available, fast-response fluorescence probe CHCQ-Ac, with 2-(5‧-chloro-2-hydroxyl-phenyl)-6-chloro-4(3 H)-quinazolinone (CHCQ) as the fluorophore and acrylate group as the functional moiety, that enables high-selectivity and high-sensitivity for detecting Cys in both solution and biological system. After specifically reacted with Cys, the probe undergoes a seven-membered intramolecular cyclization and released the fluorophore CHCQ with excited-state intramolecular photon transfer effect. A highly fluorescent, insoluble aggregate was then formed to facilitate high-sensitivity and high-resolution imaging. The results showed that probe CHCQ-Ac affords a remarkably large Stokes shift and can detect Cys under physiological pH condition with no interference from other analytes. Moreover, this probe was proved to have excellent chemical stability, low cytotoxicity and good cell permeability. Our design of this probe provides a novel potential tool to visualize and localize cysteine in bioimaging of live cells that would greatly help to explore various Cys-related physiological and pathological cellular processes in cell biology and diagnostics.

  15. Two-Photon Probes for Lysosomes and Mitochondria: Simultaneous Detection of Lysosomes and Mitochondria in Live Tissues by Dual-Color Two-Photon Microscopy Imaging.

    Science.gov (United States)

    Lim, Chang Su; Hong, Seung Taek; Ryu, Seong Shick; Kang, Dong Eun; Cho, Bong Rae

    2015-10-01

    Novel two-photon (TP) probes were developed for lysosomes (PLT-yellow) and mitochondria (BMT-blue and PMT-yellow). These probes emitted strong TP-excited fluorescence in cells at widely separated wavelength regions and displayed high organelle selectivity, good cell permeability, low cytotoxicity, and pH insensitivity. The BMT-blue and PLT-yellow probes could be utilized to detect lysosomes and mitochondria simultaneously in live tissues by using dual-color two-photon microscopy, with minimum interference from each other. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Influence of probe motion on laser probe temperature in circulating blood.

    Science.gov (United States)

    Hehrlein, C; Splinter, R; Littmann, L; Tuntelder, J R; Tatsis, G P; Svenson, R H

    1991-01-01

    The purpose of this study was to evaluate the effect of probe motion on laser probe temperature in various blood flow conditions. Laser probe temperatures were measured in an in vitro blood circulation model consisting of 3.2 nm-diameter plastic tubes. A 2.0 mm-diameter metal probe attached to a 300 microns optical quartz fiber was coupled to an argon laser. Continuous wave 4 watts and 8 watts of laser power were delivered to the fiber tip corresponding to a 6.7 +/- 0.5 and 13.2 +/- 0.7 watts power setting at the laser generator. The laser probe was either moved with constant velocity or kept stationary. A thermocouple inserted in the lateral portion of the probe was used to record probe temperatures. Probe temperature changes were found with the variation of laser power, probe velocity, blood flow, and duration of laser exposure. Probe motion significantly reduced probe temperatures. After 10 seconds of 4 watts laser power the probe temperature in stagnant blood decreased from 303 +/- 18 degrees C to 113 +/- 17 degrees C (63%) by moving the probe with a velocity of 5 cm/sec. Blood flow rates of 170 ml/min further decreased the probe temperature from 113 +/- 17 degrees C to 50 +/- 8 degrees C (56%). At 8 watts of laser power a probe temperature reduction from 591 +/- 25 degrees C to 534 +/- 36 degrees C (10%) due to 5 cm/sec probe velocity was noted. Probe temperatures were reduced to 130 +/- 30 degrees C (78%) under the combined influence of 5 cm/sec probe velocity and 170 ml/min blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Sandwich nucleic acid hybridization: a method with a universally usable labeled probe for various specific tests

    International Nuclear Information System (INIS)

    Wolf, H.; Leser, U.; Haus, M.; Gu, S.Y.; Pathmanathan, R.

    1986-01-01

    The use of recombinant m13 phages as hybridization probes offers a considerable advantage over the commonly used recombinant plasmids as the preparation of the DNA probe is very simple and it can easily be labeled directly, e.g. with isotopes with long half-life like 125 I and used for hybridization. However, as the application of nucleic acid hybridization for diagnostic and epidemiological purposes becomes almost unavoidable, the logistic problems of keeping numerous individually labeled hybridization probes increase considerably and may reach prohibitory levels in less well-equipped laboratories. In a new sandwich technique, the first step involves hybridization with an unlabeled recombinant m13 DNA carrying an insert of the desired specificity. In a second step a universally usable labeled probe directed against the m13 part of the recombinant phage DNA is applied. This reduces considerably the problem of preparing and keeping multiple labeled probes in stock. (Auth.)

  18. Diamond-coated probe head for measurements in the deep SOL and beyond

    DEFF Research Database (Denmark)

    Schrittwieser, R.; Xu, G. S.; Yan, Ning

    We have tested two cylindrical graphite probe heads coated by a layer of electrically isolating UNCD (Ultra Nano-Crystalline Diamond) using a CVD (Chemical Vapour Deposition) method. The probe heads were mounted on the reciprocating probe manipulator of the Experimental Advanced Superconducting T...

  19. An Eddy Current Testing Platform System for Pipe Defect Inspection Based on an Optimized Eddy Current Technique Probe Design

    Science.gov (United States)

    Rifai, Damhuji; Abdalla, Ahmed N.; Razali, Ramdan; Ali, Kharudin; Faraj, Moneer A.

    2017-01-01

    The use of the eddy current technique (ECT) for the non-destructive testing of conducting materials has become increasingly important in the past few years. The use of the non-destructive ECT plays a key role in the ensuring the safety and integrity of the large industrial structures such as oil and gas pipelines. This paper introduce a novel ECT probe design integrated with the distributed ECT inspection system (DSECT) use for crack inspection on inner ferromagnetic pipes. The system consists of an array of giant magneto-resistive (GMR) sensors, a pneumatic system, a rotating magnetic field excitation source and a host PC acting as the data analysis center. Probe design parameters, namely probe diameter, an excitation coil and the number of GMR sensors in the array sensor is optimized using numerical optimization based on the desirability approach. The main benefits of DSECT can be seen in terms of its modularity and flexibility for the use of different types of magnetic transducers/sensors, and signals of a different nature with either digital or analog outputs, making it suited for the ECT probe design using an array of GMR magnetic sensors. A real-time application of the DSECT distributed system for ECT inspection can be exploited for the inspection of 70 mm carbon steel pipe. In order to predict the axial and circumference defect detection, a mathematical model is developed based on the technique known as response surface methodology (RSM). The inspection results of a carbon steel pipe sample with artificial defects indicate that the system design is highly efficient. PMID:28335399

  20. Qualification of the testing process by a new rotating probe for the 900 MW PWR steam generators tubes

    International Nuclear Information System (INIS)

    Caston, D.

    2001-01-01

    In 1997, EDF invites bids for the development of eddy current probes, in order to better control the steam generator tubes rolling zone of the PWR. After examination of the response, EDF accepted a prototype of a rotating probe. The EDF specifications of the new steam generators contract, fix the inspection performance and rhythm of the rotating probe, which implements two different technic: the STL (long rotating prob)e for the detection and characterization of longitudinal defects; the STT (transverse rotating probe) for the detection and characterization of circumferential defects. The new rotating probe should not increase the control time. Two new equipments have been developed to implement this new probe: a new support and a software of online inspection with data processing and analyzing. Abstract only. (A.L.B.)

  1. Regulation of intracellular pH in LLC-PK1 cells by Na+/H+ exchange.

    Science.gov (United States)

    Montrose, M H; Murer, H

    1986-01-01

    Suspensions of LLC-PK1 cells (a continuous epitheliod cell line with renal characteristics) are examined for mechanisms of intracellular pH regulation using the fluorescent probe BCECF. Initial experiments determine suitable calibration procedures for use of the BCECF fluorescent signal. They also determine that the cell suspension contains cells which (after 4 hr in suspension) have Na+ and K+ gradients comparable to those of cells in monolayer culture. The steady-state intracellular pH (7.05 +/- 0.01, n = 5) of cells which have recovered in (pH 7.4) Na+-containing medium is not affected over several minutes by addition of 100 microM amiloride or removal of extracellular Na+ (Na+o less than 1 mM). In contrast, when the cells recover from an acid load (caused by NH4 preincubation and removal), the recovery is largely Na+ dependent and is sensitive to 100 microM amiloride. These results suggest that with resting pH near neutrality, both Na+o/H+i and Na+i/H+o exchange reactions are functionally inactive (compared to cellular buffering capacity). In contrast, Na+o/H+i exchange is activated by an increased cellular acid load. This activation may be observed directly either as a stimulation of net H+ efflux or net Na+ influx with decreasing intracellular pH. The extrapolation of this latter data suggests a "set point" of Na+/H+ exchange of approximately pH 7.0, consistent with the observed resting intracellular pH of approximately 7.05.

  2. Direct Fixed-Bed Biological Perchlorate Destruction Demonstration

    Science.gov (United States)

    2009-04-01

    FXB effluent 1/2 hours Nitrate Depth wise sample ports 1/week On-site: In-line Hach NITRATAX nitrate probe daily using a Hach DR 890 colorimeter ...tank effluent 3/week On-site: Hach DR 890 Colorimeter TTHMs DBPFP5 tests 10 total DBPFP tests MWH HAA5 DBPFP tests 10 total DBPFP tests MWH FXB... Colorimeter FXB feed Daily 2 FXB effluent Daily Post-FXB effluent Daily pH Chlorine contact tank effluent Daily On-site: Hach pH probe Temperature

  3. Study on low frequency probe characterization for concrete application

    International Nuclear Information System (INIS)

    Amry Amin Abas; Mohd Pauzi Ismail

    2002-01-01

    Ultrasonic testing has been widely used in metal and non-metal material. For non-metal material such as concrete, a probe emitting low frequency ultrasonic wave is applied. This paper describes the comparison between three custom made probes using same design and piezoelectric crystal. The only difference is the backing material, which comprise of three different materials. Characterization of each transducer is compared in order to understand the effects of backing material in the probe. (Author)

  4. Development of X-ray mini-probes for the Digiray RGX system

    International Nuclear Information System (INIS)

    Wojcik, R.; Kross, B.; Majewski, L.; Majewski, S.; Weisenberger, A.G.; Zorn, C.; Birt, E.A.; Parker, F.R.; Winfree, W.P.; Albert, R.D.; Albert, T.M.

    1994-01-01

    We have developed and tested a variety of X-ray mini-probes for the Reverse Geometry X-radiography trademark ,1 (RGX) system each having their own advantages and disadvantages. These mini-probes consist of small scintillators (as small as 2 mm in diameter and 5 mm long) attached to optical light guides (as long as 14 m) coupled to photomultipliers. Images produced with these probes show that even smaller probes and/or longer light guides may be fashioned. Such probes may be useful in both non-destructive evaluation and medical imaging. ((orig.))

  5. The pH dependence of polymerization and bundling by the essential bacterial cytoskeletal protein FtsZ.

    Directory of Open Access Journals (Sweden)

    Raúl Pacheco-Gómez

    Full Text Available There is a growing body of evidence that bacterial cell division is an intricate coordinated process of comparable complexity to that seen in eukaryotic cells. The dynamic assembly of Escherichia coli FtsZ in the presence of GTP is fundamental to its activity. FtsZ polymerization is a very attractive target for novel antibiotics given its fundamental and universal function. In this study our aim was to understand further the GTP-dependent FtsZ polymerization mechanism and our main focus is on the pH dependence of its behaviour. A key feature of this work is the use of linear dichroism (LD to follow the polymerization of FtsZ monomers into polymeric structures. LD is the differential absorption of light polarized parallel and perpendicular to an orientation direction (in this case that provided by shear flow. It thus readily distinguishes between FtsZ polymers and monomers. It also distinguishes FtsZ polymers and less well-defined aggregates, which light scattering methodologies do not. The polymerization of FtsZ over a range of pHs was studied by right-angled light scattering to probe mass of FtsZ structures, LD to probe real-time formation of linear polymeric fibres, a specially developed phosphate release assay to relate guanosine triphosphate (GTP hydrolysis to polymer formation, and electron microscopy (EM imaging of reaction products as a function of time and pH. We have found that lowering the pH from neutral to 6.5 does not change the nature of the FtsZ polymers in solution--it simply facilitates the polymerization so the fibres present are longer and more abundant. Conversely, lowering the pH to 6.0 has much the same effect as introducing divalent cations or the FtsZ-associated protein YgfE (a putative ZapA orthologue in E. coli--it stabilizes associations of protofilaments.

  6. Neurosurgical hand-held optical coherence tomography (OCT) forward-viewing probe

    Science.gov (United States)

    Sun, Cuiru; Lee, Kenneth K. C.; Vuong, Barry; Cusimano, Michael; Brukson, Alexander; Mariampillai, Adrian; Standish, Beau A.; Yang, Victor X. D.

    2012-02-01

    A prototype neurosurgical hand-held optical coherence tomography (OCT) imaging probe has been developed to provide micron resolution cross-sectional images of subsurface tissue during open surgery. This new ergonomic hand-held probe has been designed based on our group's previous work on electrostatically driven optical fibers. It has been packaged into a catheter probe in the familiar form factor of the clinically accepted Bayonet shaped neurosurgical non-imaging Doppler ultrasound probes. The optical design was optimized using ZEMAX simulation. Optical properties of the probe were tested to yield an ~20 um spot size, 5 mm working distance and a 3.5 mm field of view. The scan frequency can be increased or decreased by changing the applied voltage. Typically a scan frequency of less than 60Hz is chosen to keep the applied voltage to less than 2000V. The axial resolution of the probe was ~15 um (in air) as determined by the OCT system. A custom-triggering methodology has been developed to provide continuous stable imaging, which is crucial for clinical utility. Feasibility of this probe, in combination with a 1310 nm swept source OCT system was tested and images are presented to highlight the usefulness of such a forward viewing handheld OCT imaging probe. Knowledge gained from this research will lay the foundation for developing new OCT technologies for endovascular management of cerebral aneurysms and transsphenoidal neuroendoscopic treatment of pituitary tumors.

  7. Nano Mechanical Machining Using AFM Probe

    Science.gov (United States)

    Mostofa, Md. Golam

    Complex miniaturized components with high form accuracy will play key roles in the future development of many products, as they provide portability, disposability, lower material consumption in production, low power consumption during operation, lower sample requirements for testing, and higher heat transfer due to their very high surface-to-volume ratio. Given the high market demand for such micro and nano featured components, different manufacturing methods have been developed for their fabrication. Some of the common technologies in micro/nano fabrication are photolithography, electron beam lithography, X-ray lithography and other semiconductor processing techniques. Although these methods are capable of fabricating micro/nano structures with a resolution of less than a few nanometers, some of the shortcomings associated with these methods, such as high production costs for customized products, limited material choices, necessitate the development of other fabricating techniques. Micro/nano mechanical machining, such an atomic force microscope (AFM) probe based nano fabrication, has, therefore, been used to overcome some the major restrictions of the traditional processes. This technique removes material from the workpiece by engaging micro/nano size cutting tool (i.e. AFM probe) and is applicable on a wider range of materials compared to the photolithographic process. In spite of the unique benefits of nano mechanical machining, there are also some challenges with this technique, since the scale is reduced, such as size effects, burr formations, chip adhesions, fragility of tools and tool wear. Moreover, AFM based machining does not have any rotational movement, which makes fabrication of 3D features more difficult. Thus, vibration-assisted machining is introduced into AFM probe based nano mechanical machining to overcome the limitations associated with the conventional AFM probe based scratching method. Vibration-assisted machining reduced the cutting forces

  8. Reproducibility of the cutoff probe for the measurement of electron density

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. W.; Oh, W. Y. [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); You, S. J., E-mail: sjyou@cnu.ac.kr [Department of Physics, Chungnam National University, Daejeon 305-701 (Korea, Republic of); Kwon, J. H.; You, K. H.; Seo, B. H.; Kim, J. H., E-mail: jhkim86@kriss.re.kr [Center for Vacuum Technology, Korea Research Institute of Standards and Science, Daejeon 305-306 (Korea, Republic of); Yoon, J.-S. [Plasma Technology Research Center, National Fusion Research Institute, Gunsan 573-540 (Korea, Republic of)

    2016-06-15

    Since a plasma processing control based on plasma diagnostics attracted considerable attention in industry, the reproducibility of the diagnostics using in this application has become a great interest. Because the cutoff probe is one of the potential candidates for this application, knowing the reproducibility of the cutoff probe measurement becomes quit important in the cutoff probe application research. To test the reproducibility of the cutoff probe measurement, in this paper, a comparative study among the different cutoff probe measurements was performed. The comparative study revealed remarkable result: the cutoff probe has a great reproducibility for the electron density measurement, i.e., there are little differences among measurements by different probes made by different experimenters. The discussion including the reason for the result was addressed via this paper by using a basic measurement principle of cutoff probe and a comparative experiment with Langmuir probe.

  9. Reproducibility of the cutoff probe for the measurement of electron density

    International Nuclear Information System (INIS)

    Kim, D. W.; Oh, W. Y.; You, S. J.; Kwon, J. H.; You, K. H.; Seo, B. H.; Kim, J. H.; Yoon, J.-S.

    2016-01-01

    Since a plasma processing control based on plasma diagnostics attracted considerable attention in industry, the reproducibility of the diagnostics using in this application has become a great interest. Because the cutoff probe is one of the potential candidates for this application, knowing the reproducibility of the cutoff probe measurement becomes quit important in the cutoff probe application research. To test the reproducibility of the cutoff probe measurement, in this paper, a comparative study among the different cutoff probe measurements was performed. The comparative study revealed remarkable result: the cutoff probe has a great reproducibility for the electron density measurement, i.e., there are little differences among measurements by different probes made by different experimenters. The discussion including the reason for the result was addressed via this paper by using a basic measurement principle of cutoff probe and a comparative experiment with Langmuir probe.

  10. Dynamic regulation of gastric surface pH by luminal pH

    OpenAIRE

    Chu, Shaoyou; Tanaka, Shin; Kaunitz, Jonathan D.; Montrose, Marshall H.

    1999-01-01

    In vivo confocal imaging of the mucosal surface of rat stomach was used to measure pH noninvasively under the mucus gel layer while simultaneously imaging mucus gel thickness and tissue architecture. When tissue was superfused at pH 3, the 25 μm adjacent to the epithelial surface was relatively alkaline (pH 4.1 ± 0.1), and surface alkalinity was enhanced by topical dimethyl prostaglandin E2 (pH 4.8 ± 0.2). Luminal pH was changed from pH 3 to pH 5 to mimic the fasted-to-fed transition in intra...

  11. Hard probes (and soft ones) to test the quark-gluon soup

    CERN Multimedia

    Preuss, Paul

    2006-01-01

    "We need the hardest probes of all to study the hot, dense state of matter that exists when two heavy nuclei like gold collide with enough energy to temporarily free the quarks and gluons in their constituent protons and neutrons." (3 pages)

  12. Sensing pH via p-cyanophenylalanine fluorescence: Application to determine peptide pKa and membrane penetration kinetics.

    Science.gov (United States)

    Pazos, Ileana M; Ahmed, Ismail A; Berríos, Mariana I León; Gai, Feng

    2015-08-15

    We expand the spectroscopic utility of a well-known infrared and fluorescence probe, p-cyanophenylalanine, by showing that it can also serve as a pH sensor. This new application is based on the notion that the fluorescence quantum yield of this unnatural amino acid, when placed at or near the N-terminal end of a polypeptide, depends on the protonation status of the N-terminal amino group of the peptide. Using this pH sensor, we are able to determine the N-terminal pKa values of nine tripeptides and also the membrane penetration kinetics of a cell-penetrating peptide. Taken together, these examples demonstrate the applicability of using this unnatural amino acid fluorophore to study pH-dependent biological processes or events that accompany a pH change. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured rat caput epididymal epithelium.

    Science.gov (United States)

    Zuo, Wu-Lin; Li, Sheng; Huang, Jie-Hong; Yang, Deng-Liang; Zhang, Geng; Chen, Si-Liang; Ruan, Ye-Chun; Ye, Ke-Nan; Cheng, Christopher H K; Zhou, Wen-Liang

    2011-01-01

    The epithelium lining the epididymis provides an optimal acidic fluid microenvironment in the epididymal tract that enable spermatozoa to complete the maturation process. The present study aims to investigate the functional role of Na(+)/HCO(3)(-) cotransporter in the pH regulation in rat epididymis. Immunofluorescence staining of pan cytokeratin in the primary culture of rat caput epididymal epithelium showed that the system was a suitable model for investigating the function of epididymal epithelium. Intracellular and apical pH were measured using the fluorescent pH sensitive probe carboxy-seminaphthorhodafluor-4F acetoxymethyl ester (SNARF-4F) and sparklet pH electrode respectively to explore the functional role of rat epididymal epithelium. In the HEPES buffered Krebs-Henseleit (KH) solution, the intracellular pH (pHi) recovery from NH(4)Cl induced acidification in the cultured caput epididymal epithelium was completely inhibited by amiloride, the inhibitor of Na(+)/H(+) exchanger (NHE). Immediately changing of the KH solution from HEPES buffered to HCO(3)(-) buffered would cause another pHi recovery. The pHi recovery in HCO(3)(-) buffered KH solution was inhibited by 4, 4diisothiocyanatostilbene-2,2-disulfonic acid (DIDS), the inhibitor of HCO(3)(-) transporter or by removal of extracellular Na(+). The extracellular pH measurement showed that the apical pH would increase when adding DIDS to the apical side of epididymal epithelial monolayer, however adding DIDS to the basolateral side had no effect on apical pH. The present study shows that sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured caput epididymal epithelium.

  14. IMPACT OF WATER PH ON ZEBRA MUSSEL MORTALITY

    International Nuclear Information System (INIS)

    Molloy, Daniel P.

    2002-01-01

    The experiments conducted this past quarter have suggested that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels throughout the entire range of pH values tested (7.2 to 8.6). Highest mortality was achieved at pH values characteristic of preferred zebra mussel waterbodies, i.e., hard waters with a range of 7.8 to 8.6. In all water types tested, however, ranging from very soft to very hard, considerable mussel kill was achieved (83 to 99% mean mortality), suggesting that regardless of the pH or hardness of the treated water, significant mussel kill can be achieved upon treatment with P. fluorescens strain CL0145A. These results further support the concept that this bacterium has significant potential for use as a zebra mussel control agent in power plant pipes receiving waters with a wide range of physical and chemical characteristics

  15. IMPACT OF WATER PH ON ZEBRA MUSSEL MORTALITY

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2002-10-15

    The experiments conducted this past quarter have suggested that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels throughout the entire range of pH values tested (7.2 to 8.6). Highest mortality was achieved at pH values characteristic of preferred zebra mussel waterbodies, i.e., hard waters with a range of 7.8 to 8.6. In all water types tested, however, ranging from very soft to very hard, considerable mussel kill was achieved (83 to 99% mean mortality), suggesting that regardless of the pH or hardness of the treated water, significant mussel kill can be achieved upon treatment with P. fluorescens strain CL0145A. These results further support the concept that this bacterium has significant potential for use as a zebra mussel control agent in power plant pipes receiving waters with a wide range of physical and chemical characteristics.

  16. Optic nerve pH and PO2

    DEFF Research Database (Denmark)

    Pedersen, Daniella B; Stefánsson, Einar; Kiilgaard, Jens Folke

    2006-01-01

    Earlier studies have demonstrated that carbonic anhydrase inhibitors (CAIs) increase optic nerve oxygen tension (ONPO(2)) in pigs. We hypothesized that the mechanism of this effect was either a CO(2) increase or a pH decrease in tissue and blood. To test this hypothesis we investigated and compared...... how optic nerve pH (ONpH) and ONPO(2) are affected by: (1) carbonic anhydrase inhibition; (2) respiratory acidosis, and (3) metabolic acidosis. We measured ONpH with a glass pH electrode and ONPO(2) with a polarographic oxygen electrode. One of the electrodes was placed in the vitreous cavity 0.5 mm...... over the optic nerve in the eyes of domestic pigs....

  17. Dielectrophoresis Aligned Single-Walled Carbon Nanotubes as pH Sensors.

    Science.gov (United States)

    Li, Pengfei; Martin, Caleb M; Yeung, Kan Kan; Xue, Wei

    2011-01-31

    Here we report the fabrication and characterization of pH sensors using aligned single-walled carbon nanotubes (SWNTs). The SWNTs are dispersed in deionized (DI) water after chemical functionalization and filtration. They are deposited and organized on silicon substrates with the dielectrophoresis process. Electrodes with "teeth"-like patterns-fabricated with photolithography and wet etching-are used to generate concentrated electric fields and strong dielectrophoretic forces for the SWNTs to deposit and align in desired locations. The device fabrication is inexpensive, solution-based, and conducted at room temperature. The devices are used as pH sensors with the electrodes as the testing pads and the dielectrophoretically captured SWNTs as the sensing elements. When exposed to aqueous solutions with various pH values, the SWNTs change their resistance accordingly. The SWNT-based sensors demonstrate a linear relationship between the sensor resistance and the pH values in the range of 5-9. The characterization of multiple sensors proves that their pH sensitivity is highly repeatable. The real-time data acquisition shows that the sensor response time depends on the pH value, ranging from 2.26 s for the pH-5 solution to 23.82 s for the pH-9 solution. The long-term stability tests illustrate that the sensors can maintain their original sensitivity for a long period of time. The simple fabrication process, high sensitivity, and fast response of the SWNT-based sensors facilitate their applications in a wide range of areas.

  18. Esophageal scintigraphy and pH monitoring in adults with gastroesophageal reflux

    Energy Technology Data Exchange (ETDEWEB)

    Jouin, H.; Chamouard, P.; Baumann, R. and others

    1987-10-01

    Thirty-seven adults with gastroesophageal reflux were explored by oesophageal scintigraphy and pH monitoring (three hours postprandial). Scintigraphy was less frequently positive than pH test in gastroesophageal reflux (81% versus 57%) with a significant difference. It is suggested that postprandial pH monitoring is reliable in the initial assessment of symptomatic gastroesophageal reflux.

  19. A simple rhodamine hydrazide-based turn-on fluorescent probe for HOCl detection.

    Science.gov (United States)

    Zhang, Zhen; Zou, Yuan; Deng, Chengquan; Meng, Liesu

    2016-06-01

    Hypochlorous acid (HOCl) plays a crucial role in daily life and mediates a variety of physiological processes, however, abnormal levels of HOCl have been associated with numerous human diseases. It is therefore of significant interest to establish a simple, selective, rapid and sensitive fluorogenic method for the detection of HOCl in environmental and biological samples. A hydrazide-containing fluorescent probe based on a rhodamine scaffold was facilely developed that could selectively detect HOCl over other biologically relevant reactive oxygen species, reactive nitrogen species and most common metal ions in vitro. Via an irreversible oxidation-hydrolysis mechanism, and upon HOCl-triggered opening of the intramolecular spirocyclic ring during detection, the rhodamine hydrazide-based probe exhibited large fluorescence enhancement in the emission spectra with a fast response, low detection limit and comparatively wide pH detection range in aqueous media. The probe was further successfully applied to monitoring trace HOCl in tap water and imaging both exogenous and endogenous HOCl within living cells. It is anticipated that this simple and useful probe might be an efficient tool with which to facilitate more HOCl-related chemical and biological research. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  20. The photostability of the commonly used biotin-4-fluorescein probe.

    Science.gov (United States)

    Haack, Richard A; Swift, Kerry M; Ruan, Qiaoqiao; Himmelsbach, Richard J; Tetin, Sergey Y

    2017-08-15

    Biotin-4-fluorescein (B4F) is a commonly used fluorescent probe for studying biotin-(strept)avidin interactions. During a characterization study of an anti-biotin antibody, using B4F as the probe, we noticed a discrepancy in the expected and experimentally determined number of biotin binding sites. Analytical testing showed that the biotin moiety in the probe undergoes a photosensitized oxidation to produce a mixture of biotin sulfoxides which has the potential to impact the quantitation of binding sites using this fluorescent probe. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Probing surface charge potentials of clay basal planes and edges by direct force measurements.

    Science.gov (United States)

    Zhao, Hongying; Bhattacharjee, Subir; Chow, Ross; Wallace, Dean; Masliyah, Jacob H; Xu, Zhenghe

    2008-11-18

    The dispersion and gelation of clay suspensions have major impact on a number of industries, such as ceramic and composite materials processing, paper making, cement production, and consumer product formulation. To fundamentally understand controlling mechanisms of clay dispersion and gelation, it is necessary to study anisotropic surface charge properties and colloidal interactions of clay particles. In this study, a colloidal probe technique was employed to study the interaction forces between a silica probe and clay basal plane/edge surfaces. A muscovite mica was used as a representative of 2:1 phyllosilicate clay minerals. The muscovite basal plane was prepared by cleavage, while the edge surface was obtained by a microtome cutting technique. Direct force measurements demonstrated the anisotropic surface charge properties of the basal plane and edge surface. For the basal plane, the long-range forces were monotonically repulsive within pH 6-10 and the measured forces were pH-independent, thereby confirming that clay basal planes have permanent surface charge from isomorphic substitution of lattice elements. The measured interaction forces were fitted well with the classical DLVO theory. The surface potentials of muscovite basal plane derived from the measured force profiles were in good agreement with those reported in the literature. In the case of edge surfaces, the measured forces were monotonically repulsive at pH 10, decreasing with pH, and changed to be attractive at pH 5.6, strongly suggesting that the charge on the clay edge surfaces is pH-dependent. The measured force profiles could not be reasonably fitted with the classical DLVO theory, even with very small surface potential values, unless the surface roughness was considered. The surface element integration (SEI) method was used to calculate the DLVO forces to account for the surface roughness. The surface potentials of the muscovite edges were derived by fitting the measured force profiles with the

  2. User's Manual for ProbeCorder (Version 1.0) Data Collection Software

    National Research Council Canada - National Science Library

    Zeidler, James

    1997-01-01

    ProbeCorder is a pen-based software tool designed to maximize the logostocal efficiency of subsurface soil testing by automating the routine collection, integration, and storage of probe data in the field...

  3. Synthesis of ¹³C-lidocaine as a probe of breath test for the evaluation of cytochrome P450 activity.

    Science.gov (United States)

    Mitome, Hidemichi; Sugiyama, Erika; Sato, Hitoshi; Akira, Kazuki

    2014-01-01

    (13)C-Labeled lidocaine, 2-di[1-(13)C]ethylamino-N-(2,6-dimethylphenyl)acetamide (1), was synthesized from [1-(13)C]acetic acid in six steps, as a probe for a breath test to evaluate in vivo cytochrome P450 activity. The measurement of (13)CO2 in breath was successfully performed following oral administration of (13)C-lidocaine 1 to mice.

  4. Plant based dietary supplement increases urinary pH

    Directory of Open Access Journals (Sweden)

    Rao A Venket

    2008-11-01

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

  5. Probes for corrosion-related variables in LWR coolant: Interim report

    International Nuclear Information System (INIS)

    Madou, M.; McKubre, M.C.H.

    1987-08-01

    The objectives of this study were to identify, develop, and qualify a range of sensors for the measurement and control of corrosion in high temperature, flowing water, nuclear reactor heat transport systems. Sensors were developed for the quantitative determination of pH, redox potential, and dissolved hydrogen concentration. A necessary first step in the development of voltage sensors is the availability of a stable thermodynamic reference electrode suitable for use in the high temperature aqueous environments of interest, and an external, pressure balanced, reference electrode was developed for this purpose. Experiments were performed to verify sensor function under conditions simulating those in nuclear reactor aqueous heat transport systems. The results indicate that dissolved hydrogen levels can be reliably sensed in PWR primary coolant. The probes for pH and redox potential await the development of a longer-lived reference electrode which is being actively pursued

  6. Imaging intracellular pH in a reef coral and symbiotic anemone.

    Science.gov (United States)

    Venn, A A; Tambutté, E; Lotto, S; Zoccola, D; Allemand, D; Tambutté, S

    2009-09-29

    The challenges corals and symbiotic cnidarians face from global environmental change brings new urgency to understanding fundamental elements of their physiology. Intracellular pH (pHi) influences almost all aspects of cellular physiology but has never been described in anthozoans or symbiotic cnidarians, despite its pivotal role in carbon concentration for photosynthesis and calcification. Using confocal microscopy and the pH sensitive probe carboxy SNARF-1, we mapped pHi in short-term light and dark-incubated cells of the reef coral Stylophora pistillata and the symbiotic anemone Anemonia viridis. In all cells isolated from both species, pHi was markedly lower than the surrounding seawater pH of 8.1. In cells that contained symbiotic algae, mean values of pHi were significantly higher in light treated cells than dark treated cells (7.41 +/- 0.22 versus 7.13 +/- 0.24 for S. pistillata; and 7.29 +/- 0.15 versus 7.01 +/- 0.27 for A. viridis). In contrast, there was no significant difference in pHi in light and dark treated cells without algal symbionts. Close inspection of the interface between host cytoplasm and algal symbionts revealed a distinct area of lower pH adjacent to the symbionts in both light and dark treated cells, possibly associated with the symbiosome membrane complex. These findings are significant developments for the elucidation of models of inorganic carbon transport for photosynthesis and calcification and also provide a cell imaging procedure for future investigations into how pHi and other fundamental intracellular parameters in corals respond to changes in the external environment such as reductions in seawater pH.

  7. Short-term carcinogenicity testing of a potent murine intestinal mutagen, 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), in Apc1638N transgenic mice

    DEFF Research Database (Denmark)

    Sørensen, Ilona Kryspin; Kristiansen, E.; Mortensen, Alicja

    1997-01-01

    others, mammary tumors, We have studied these mice in a short-term carcinogenicity test with 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), a potent murine small intestinal mutagen and lymphomagen. Upon dietary administration of 0.03% PhIP in a short-term (6 months) study, a significantly...

  8. Esophageal scintigraphy and pH monitoring in adults with gastroesophageal reflux

    International Nuclear Information System (INIS)

    Jouin, H.; Chamouard, P.; Baumann, R.

    1987-01-01

    Thirty-seven adults with gastroesophageal reflux were explored by oesophageal scintigraphy and pH monitoring (three hours postprandial). Scintigraphy was less frequently positive than pH test in gastroesophageal reflux (81% versus 57%) with a significant difference. It is suggested that postprandial pH monitoring is reliable in the initial assessment of symptomatic gastroesophageal reflux [fr

  9. Glutathione-stabilized Cu nanoclusters as fluorescent probes for sensing pH and vitamin B1.

    Science.gov (United States)

    Luo, Yawen; Miao, Hong; Yang, Xiaoming

    2015-11-01

    Glutathione (GSH), playing roles as both a reducing reagent and protecting ligand, has been successfully employed for synthesizing Cu nanoclusters (CuNCs@GSH) on the basis of a simple and facile approach. The as-prepared CuNCs exhibited a fluorescence emission at 600nm with a quantum yield (QY) of approximately 3.6%. Subsequently, the CuNCs described here was employed as a broad-range pH sensor by virtue of the fluorescence intensity of CuNCs responding sensitively to pH fluctuating in a linear range of 4.0-12.0. Meanwhile, these prepared CuNCs were applied for detections of vitamin B1 (VB1) on the basis of positively charged VB1 neutralizing the negative surface charge of CuNCs, thus leading to the instability and aggregations of CuNCs, and further facilitating to quench their fluorescence. In addition, the proposed analytical method permitted detecting VB1 with a linear range of 2.0×10(-8)-1.0×10(-4) mol L(-1) as well as a detection limit of 4.6×10(-9) mol L(-1). Eventually, the practicability of this sensing approach was validated by assaying VB1 in human urine samples and pharmaceutical tablets, confirming its potential to broaden avenues for assaying VB1. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. The pH dependent toxicity and bioaccumulation of chloroquine tested on S. viminalis (basket willow)

    DEFF Research Database (Denmark)

    Rendal, Cecilie; Trapp, Stefan; Legind, Charlotte Nielsen

    2010-01-01

    (hydroxymethyl) – aminomethane (pH 8 and 9). Concentrations were determined with spectrophotometer. Toxicity was derived from calculations of normalized transpiration over time, and RCF (root concentration factor) values were calculated. Increasing BCF values were found for increasing pH levels, and the toxicity...

  11. Shear bond strength of one-step self-etch adhesives: pH influence

    Science.gov (United States)

    Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

    2015-01-01

    Background: The aim of this study was to compare the shear bond strength of four one-step self-etch adhesives with different pH values to enamel and dentin. Materials and Methods: In this in vitro study, 200 bovine permanent mandibular incisors were used. Four one-step self-etch adhesives with different pH values were tested both on enamel and on dentin: Adper™ Easy Bond Self-Etch Adhesive (pH = 0.8-1), Futurabond NR (pH=2), G-aenial Bond (pH = 1.5), Clearfil S3 Bond (pH = 2.7). After adhesive systems application, a nanohybrid composite resin was inserted into the bonded surface. The specimens were placed in a universal testing machine. The shear bond strength was performed at a cross-head speed of 1 mm/min until the sample rupture. The shear bond strength values (MPa) of the different groups were compared with analysis of variance after that Kolmogorov and Smirnov tests were applied to assess normality of distributions. P enamel shear bond strength, the highest shear bond strength values were reported with Futurabond NR (P adhesive systems showed lower shear bond strength values with significant differences between them (P 0.05). Conclusion: The pH values of adhesive systems did not influence significantly their shear bond strength to enamel or dentin. PMID:26005459

  12. Joint tests at INL and CEA of a transient hot wire needle probe for in-pile thermal conductivity measurement

    International Nuclear Information System (INIS)

    Daw, J.E.; Knudson, D.L.; Villard, J.F.; Liothin, J.; Destouches, C.; Rempe, J.L.; Matheron, P.; Lambert, T.

    2015-01-01

    Thermal conductivity is a key property that must be known for proper design, testing, and deployment of new fuels and structural materials in nuclear reactors. Thermal conductivity is highly dependent on the physical structure, chemical composition, and the state of the material. Typically, thermal conductivity changes that occur during irradiation are currently measured out-of-pile using a 'cook and look' approach. But repeatedly removing samples from a test reactor to make measurements is expensive, has the potential to disturb phenomena of interest, and only provides understanding of the sample's end state when each measurement is made. There are also limited thermo-physical property data available for advanced fuels; and such data are needed for simulation codes, the development of next generation reactors, and advanced fuels for existing nuclear plants. Being able to quickly characterize fuel thermal conductivity during irradiation can improve the fidelity of data, reduce costs of post-irradiation examinations, increase understanding of how fuels behave under irradiation, and confirm or improve existing thermal conductivity measurement techniques. This paper discusses efforts to develop and evaluate an innovative in-pile thermal conductivity sensor based on the transient hot wire thermal conductivity method (THWM), using a single needle probe (NP) containing a line heat source and thermocouple embedded in the fuel. The sensor that has been designed and manufactured by the Idaho National Laboratory (INL) includes a unique combination of materials, geometry, and fabrication techniques that make the hot wire method suitable for in-pile applications. In particular, efforts were made to minimize the influence of the sensor and maximize fuel hot-wire heating. The probe has a thermocouple-like construction with high temperature resistant materials that remain ductile while resisting transmutation and materials interactions. THWM-NP prototypes were

  13. Joint tests at INL and CEA of a transient hot wire needle probe for in-pile thermal conductivity measurement

    Energy Technology Data Exchange (ETDEWEB)

    Daw, J.E.; Knudson, D.L. [Idaho National Laboratory, Idaho Falls, ID 83415, (United States); Villard, J.F.; Liothin, J.; Destouches, C. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St Paul-Lez-Durance, (France); Rempe, J.L. [Rempe and Associates, LLC, Idaho Falls, ID, 83404 (United States); Matheron, P. [CEA, DEN, DEC, Uranium Fuels Laboratory, Cadarache, F-13108 St Paul-Lez-Durance, (France); Lambert, T. [CEA, DEN, DEC, Innovative Fuel Design and Irradiation Laboratory, Cadarache, F-13108 St Paul-Lez-Durance, (France)

    2015-07-01

    Thermal conductivity is a key property that must be known for proper design, testing, and deployment of new fuels and structural materials in nuclear reactors. Thermal conductivity is highly dependent on the physical structure, chemical composition, and the state of the material. Typically, thermal conductivity changes that occur during irradiation are currently measured out-of-pile using a 'cook and look' approach. But repeatedly removing samples from a test reactor to make measurements is expensive, has the potential to disturb phenomena of interest, and only provides understanding of the sample's end state when each measurement is made. There are also limited thermo-physical property data available for advanced fuels; and such data are needed for simulation codes, the development of next generation reactors, and advanced fuels for existing nuclear plants. Being able to quickly characterize fuel thermal conductivity during irradiation can improve the fidelity of data, reduce costs of post-irradiation examinations, increase understanding of how fuels behave under irradiation, and confirm or improve existing thermal conductivity measurement techniques. This paper discusses efforts to develop and evaluate an innovative in-pile thermal conductivity sensor based on the transient hot wire thermal conductivity method (THWM), using a single needle probe (NP) containing a line heat source and thermocouple embedded in the fuel. The sensor that has been designed and manufactured by the Idaho National Laboratory (INL) includes a unique combination of materials, geometry, and fabrication techniques that make the hot wire method suitable for in-pile applications. In particular, efforts were made to minimize the influence of the sensor and maximize fuel hot-wire heating. The probe has a thermocouple-like construction with high temperature resistant materials that remain ductile while resisting transmutation and materials interactions. THWM-NP prototypes were

  14. Characterisation and deployment of an immobilised pH sensor spot towards surface ocean pH measurements.

    Science.gov (United States)

    Clarke, Jennifer S; Achterberg, Eric P; Rérolle, Victoire M C; Abi Kaed Bey, Samer; Floquet, Cedric F A; Mowlem, Matthew C

    2015-10-15

    The oceans are a major sink for anthropogenic atmospheric carbon dioxide, and the uptake causes changes to the marine carbonate system and has wide ranging effects on flora and fauna. It is crucial to develop analytical systems that allow us to follow the increase in oceanic pCO2 and corresponding reduction in pH. Miniaturised sensor systems using immobilised fluorescence indicator spots are attractive for this purpose because of their simple design and low power requirements. The technology is increasingly used for oceanic dissolved oxygen measurements. We present a detailed method on the use of immobilised fluorescence indicator spots to determine pH in ocean waters across the pH range 7.6-8.2. We characterised temperature (-0.046 pH/°C from 5 to 25 °C) and salinity dependences (-0.01 pH/psu over 5-35), and performed a preliminary investigation into the influence of chlorophyll on the pH measurement. The apparent pKa of the sensor spots was 6.93 at 20 °C. A drift of 0.00014 R (ca. 0.0004 pH, at 25 °C, salinity 35) was observed over a 3 day period in a laboratory based drift experiment. We achieved a precision of 0.0074 pH units, and observed a drift of 0.06 pH units during a test deployment of 5 week duration in the Southern Ocean as an underway surface ocean sensor, which was corrected for using certified reference materials. The temperature and salinity dependences were accounted for with the algorithm, R=0.00034-0.17·pH+0.15·S(2)+0.0067·T-0.0084·S·1.075. This study provides a first step towards a pH optode system suitable for autonomous deployment. The use of a short duration low power illumination (LED current 0.2 mA, 5 μs illumination time) improved the lifetime and precision of the spot. Further improvements to the pH indicator spot operations include regular application of certified reference materials for drift correction and cross-calibration against a spectrophotometric pH system. Desirable future developments should involve novel

  15. How to Say No: Single- and Dual-Process Theories of Short-Term Recognition Tested on Negative Probes

    Science.gov (United States)

    Oberauer, Klaus

    2008-01-01

    Three experiments with short-term recognition tasks are reported. In Experiments 1 and 2, participants decided whether a probe matched a list item specified by its spatial location. Items presented at study in a different location (intrusion probes) had to be rejected. Serial position curves of positive, new, and intrusion probes over the probed…

  16. Low-Temperature Band Transport and Impact of Contact Resistance in Organic Field-Effect Transistors Based on Single-Crystal Films of Ph-BTBT-C10

    Science.gov (United States)

    Cho, Joung-min; Mori, Takehiko

    2016-06-01

    Transistors based on single-crystal films of 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) fabricated using the blade-coating method are investigated by the four-probe method down to low temperatures. The four-probe mobility is as large as 18 cm2/V s at room temperature, and increases to 45 cm2/V s at 80 K. At 60 K the two-probe mobility drops abruptly by about 50%, but the mobility drop is mostly attributed to the increase of the source resistance. The carrier transport in the present single-crystal film is regarded as essentially bandlike down to 30 K.

  17. Immobilization of Cd, Zn, and Pb from Soil Treated by Limestone with Variation of pH Using a Column Test

    Directory of Open Access Journals (Sweden)

    Sung-Wook Yun

    2015-01-01

    Full Text Available Decades of mining in South Korea have resulted in the contamination of large amounts of soil by metals. The most feasible approach to site restoration requires the use of a stabilization agent to reduce metal mobility. This study examined the leaching characteristics of limestone used as a stabilization agent when subjected to solutions of differing pH. In a laboratory-scale column test, solutions with pH values of 3.5, 4.6, and 5.6, representing acidic to nonacidic rainfall, were applied to soil mixed with limestone. Test results indicate that metal components can be released with the addition of acidic solutions, even if the soil is highly alkaline. Cd and Zn, in particular, exhibited abrupt or continuous leaching when exposed to acid solutions, indicating the potential for contamination of water systems as metal-laden soils are exposed to the slightly acidic rainfall typical of South Korea. Treatment using stabilization agents such as limestone may reduce leaching of metals from the contaminated soil. Stabilizing metal-contaminated farmland is an economical and feasible way to reduce pollutants around abandoned metal mines.

  18. Four-probe measurements with a three-probe scanning tunneling microscope

    International Nuclear Information System (INIS)

    Salomons, Mark; Martins, Bruno V. C.; Zikovsky, Janik; Wolkow, Robert A.

    2014-01-01

    We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe

  19. Four-probe measurements with a three-probe scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Salomons, Mark [National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2M9 (Canada); Martins, Bruno V. C.; Zikovsky, Janik; Wolkow, Robert A., E-mail: rwolkow@ualberta.ca [National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2M9 (Canada); Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)

    2014-04-15

    We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

  20. Four-probe measurements with a three-probe scanning tunneling microscope.

    Science.gov (United States)

    Salomons, Mark; Martins, Bruno V C; Zikovsky, Janik; Wolkow, Robert A

    2014-04-01

    We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

  1. Characterizing Water Quenching Systems with a Quench Probe

    Science.gov (United States)

    Ferguson, B. Lynn; Li, Zhichao; Freborg, Andrew M.

    2014-12-01

    Quench probes have been used effectively to characterize the quality of quenchants for many years. For this purpose, a variety of commercial probes, as well as the necessary data acquisition system for determining the time-temperature data for a set of standardized test conditions, are available for purchase. The type of information obtained from such probes provides a good basis for comparing media, characterizing general cooling capabilities, and checking media condition over time. However, these data do not adequately characterize the actual production quenching process in terms of heat transfer behavior in many cases, especially when high temperature gradients are present. Faced with the need to characterize water quenching practices, including conventional and intensive practices, a quench probe was developed. This paper describes that probe, the data collection system, the data gathered for both intensive quenching and conventional water quenching, and the heat transfer coefficients determined for these processes. Process sensitivities are investigated and highlight some intricacies of quenching.

  2. Influence of high intensity ultrasound with different probe diameter ...

    African Journals Online (AJOL)

    The main goal of this research is to analyze the influence of ultrasonic probe diameters (7 and 10 mm) of high-intensity ultrasound with constant frequency (30 kHz) on the degree of homogenization (variance) of cow milk. Influence of different probe diameters on the physical properties of cow milk was also tested. Changes ...

  3. Dielectrophoresis Aligned Single-Walled Carbon Nanotubes as pH Sensors

    Directory of Open Access Journals (Sweden)

    Wei Xue

    2011-01-01

    Full Text Available Here we report the fabrication and characterization of pH sensors using aligned single-walled carbon nanotubes (SWNTs. The SWNTs are dispersed in deionized (DI water after chemical functionalization and filtration. They are deposited and organized on silicon substrates with the dielectrophoresis process. Electrodes with “teeth”-like patterns—fabricated with photolithography and wet etching—are used to generate concentrated electric fields and strong dielectrophoretic forces for the SWNTs to deposit and align in desired locations. The device fabrication is inexpensive, solution-based, and conducted at room temperature. The devices are used as pH sensors with the electrodes as the testing pads and the dielectrophoretically captured SWNTs as the sensing elements. When exposed to aqueous solutions with various pH values, the SWNTs change their resistance accordingly. The SWNT-based sensors demonstrate a linear relationship between the sensor resistance and the pH values in the range of 5–9. The characterization of multiple sensors proves that their pH sensitivity is highly repeatable. The real-time data acquisition shows that the sensor response time depends on the pH value, ranging from 2.26 s for the pH-5 solution to 23.82 s for the pH-9 solution. The long-term stability tests illustrate that the sensors can maintain their original sensitivity for a long period of time. The simple fabrication process, high sensitivity, and fast response of the SWNT-based sensors facilitate their applications in a wide range of areas.

  4. Influence of pH and media composition on suspension stability of silver, zinc oxide, and titanium dioxide nanoparticles and immobilization of Daphnia magna under guideline testing conditions.

    Science.gov (United States)

    Cupi, Denisa; Hartmann, Nanna B; Baun, Anders

    2016-05-01

    In aquatic toxicity testing of engineered nanoparticles (ENPs) the process of agglomeration is very important as it may alter bioavailability and toxicity. In the present study, we aimed to identify test conditions that are favorable for maintaining stable ENP suspensions. We evaluated the influence of key environmental parameters: pH (2-12) and ionic strength using M7, Soft EPA (S EPA) medium, and Very Soft EPA (VS EPA) medium; and observed the influence of these parameters on zeta potential, zeta average, and acute immobilization of Daphnia magna for three different ENPs. Despite being sterically stabilized, test suspensions of silver (Ag) ENPs formed large agglomerates in both VS EPA and M7 media; and toxicity was found to be higher in VS EPA medium due to increased dissolution. Low-agglomerate suspensions for zinc oxide (ZnO) could be obtained at pH 7 in VS EPA medium, but the increase in dissolution caused higher toxicity than in M7 medium. Titanium dioxide (TiO2) ENPs had a point of zero charge in the range of pH 7-8. At pH 7 in VS EPA, agglomerates with smaller hydrodynamic diameters (~200nm) were present compared to the high ionic strength M7 medium where hydrodynamic diameters reached micrometer range. The stable suspensions of TiO2 ENPs caused immobilization of D. magna, 48-h EC50 value of 13.7mgL(-1) (95% CI, 2.4mg-79.1mgL(-1)); whereas no toxicity was seen in the unstable, highly agglomerated M7 medium suspensions, 48-h EC50 >100mgL(-1). The current study provides a preliminary approach for methodology in testing and assessing stability and toxicity of ENPs in aquatic toxicity tests of regulatory relevance. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Post-irradiation characterization of PH13-8Mo martensitic stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Jong, M.; Schmalz, F.; Rensman, J.W. [Nuclear Research and consultancy Group, Westerduinweg 3, 1755 ZG Petten (Netherlands); Luzginova, N.V., E-mail: luzginova@nrg.eu [Nuclear Research and consultancy Group, Westerduinweg 3, 1755 ZG Petten (Netherlands); Wouters, O.; Hegeman, J.B.J.; Laan, J.G. van der [Nuclear Research and consultancy Group, Westerduinweg 3, 1755 ZG Petten (Netherlands)

    2011-10-01

    The irradiation response of PH13-8Mo stainless steel was measured up to 2.5 dpa at 200 and 300 deg. C irradiation temperatures. The PH13-8Mo, a martensitic precipitation-hardened steel, was produced by Hot Isostatic Pressing at 1030 deg. C. The fatigue tests (high cycle fatigue and fatigue crack propagation) showed a test temperature dependency but no irradiation effects. Tensile tests showed irradiation hardening (yield stress increase) of approximately 37% for 200 deg. C irradiated material tested at 60 deg. C and approximately 32% for 300 deg. C irradiated material tested at 60 deg. C. This contradicts the shift in reference temperature (T{sub 0}) measured in toughness tests (Master Curve approach), where the {Delta}T{sub 0} for 300 deg. C irradiated is approximately 170 deg. C and the {Delta}T{sub 0} for the 200 deg. C irradiated is approximately 160 deg. C. This means that the irradiation hardening of PH13-8Mo steel is not suitable to predict the shift in the reference temperature for the Master Curve approach.

  6. Testing device for pipeline groups and control method for testing device

    International Nuclear Information System (INIS)

    Naito, Shinji; Kajiyama, Shigeru; Takahashi, Fuminobu; Tsuchida, Kenji; Tachibana, Yukio; Shigehiro, Katsuya; Mahara, Yoichi.

    1995-01-01

    The device of the present invention comprises a testing device main body disposed to a rail, a movable mechanism positioning from a reference point, a circumferential direction scanning mechanism, an axial direction scanning mechanism, a posture control mechanism, and a testing probe. Upon testing of pipelines, the detection device main body and auxiliary members are moved from a reference point previously set on a rail for numerical control toward pipelines to be tested in a state where the axial direction scanning mechanism and the testing probe are suspended in the axial direction. The testing is conducted by controlling the position of the testing probe in the axial direction of the pipeline by means of the axial direction scanning mechanism, and scanning the testing probe to the outer circumference of the pipeline along the circumferential track by way of the circumferential direction scanning mechanism. The device can be extremely reduced in the thickness, and can be moved with no interference with pipelines and other obstacles by remote operation even under such undesired condition as the pipelines being crowded, so that non-destructive testing can be conducted accurately. (N.H.)

  7. Genotypic characterization of Rickettsiae by DNA probes generated from Rickettsia Prowazekii DNA

    International Nuclear Information System (INIS)

    Demkin, V.V.; Rydkina, E.B.; Likhoded, L.Ya.; Ignatovich, V.F.; Genig, V.A.; Balayeva, N.M.

    1994-01-01

    Southern blot analysis of HindIII-cleaved rickettsial DNA was used for genotypic characterization of the typhus group (TG) species (R. prowazekii, R. typhi, R. canada) and a few species were of the spotted fever group (SFG)rickettsiae (R. sibirica, R. conorii, R. akari). Four different DNA probes were employed. PBH11 and PBH13 probes were morphospecific HindIII fragment of R prowazekii DNA. MW218 probe contained the gene for 51 K antigen and MW264 probe contained the citrate synthase gene of R. prowazekii. All the probes hybridized with the tested TG and SFG rickettsial DNAs, forming from 1 to 5 bands, but they did not with R. tsutsudamushi or C. burnetii DNAs. All the probes demonstrated specific hybridization pattern with TG species and R. akari. PBH11. PBH13 and MW264 probes clearly distinguished R. sibirica and R. conorii from the other tested rickettsiae, but not from each other. However, these two species differed slightly with MW218 probe. Several strains of each species were analyzed in this way and except for strains of R. conorii identical intra-species pattern were obtained. These data lead us to consider the obtained hybridization patterns as criteria for genotypic identification. (author)

  8. Correlation of transmissive fractures in holes OL-PH1, ONK-PH2 .. ONK-PH7 and ONKALO tunnel fractures

    International Nuclear Information System (INIS)

    Palmen, J; Nummela, J.; Ahokas, H.

    2011-02-01

    In a preceding study Posiva flow logging (PFL) with a 0.5 m test interval and 10 cm steps has been used together with optical drillhole images and core logging fracture data for the exact determination of the depth of hydraulically conductive fractures in pilot holes. The fracture traces has been mapped from the ONKALO tunnel walls as a part of the systematic mapping. The mapping results has been digitized to a 3D tunnel layout in Surpac Vision programme. The data integrity and fracture trace uniqueness has been verified by Datactica Oy and further collected to a database (Rakokanta D atactica P osiva20091119.mdb). Water leakage of the mapped fractures exists as an attribute field for each fracture, but the value of the attribute has not been assessed conclusively. Those fractures mapped with leakage attribute have been defined as flowing, dripping, wet, or damp where the attribute is recorded. The fractures with no leakage attribute value appear to be dry (not leaking) or the information is not available (assessment was not performed). The water leaking surfaces on ONKALO tunnel wall have been mapped sequentially and conclusively (twice a year) as a part of the Olkiluoto monitoring program (OMO) using an equal five step measure as used with fracture traces in systematic mapping. The PFL results correlated with core logging fracture data from pilot holes OL-PH1 and ONK-PH2 .. ONK-PH7 were in this work further correlated with the fractures mapped from the ONKALO tunnel walls. Each hydraulically conductive fracture of OL-PH1 and ONK-PH2 - ONK-PH7 was investigated and linked to ONKALO fracture of a coherent orientation and matching location, where such fracture trace was available. The main objective of the work was to identify the ONKALO fractures which correspond to the flow from fracture(s) identified with the PFL method in pilot holes and to collect basic information about the occurrence, frequency and orientation of water bearing fractures along ONKALO tunnel

  9. Influence of pH on optoelectronic properties of zinc sulphide thin films prepared using hydrothermal and spin coating method

    Science.gov (United States)

    Choudapur, V. H.; Bennal, A. S.; Raju, A. B.

    2018-04-01

    The ZnS nanomaterial is synthesized by hydrothermal method under optimized conditions using Zinc acetate and sodium sulphide as precursors. The Zinc Sulphide thin films are obtained by simple spin coating method with high optical transmittance. The prepared thin films are adhesive and uniform. The x-ray diffraction analysis showed that the films are polycrystalline in cubic phase with the preferred orientation along (111) direction. Current-voltage curves were recorded at room temperature using Keithley 617 programmable electrometer and conductivity is calculated for the film coated on ITO by two probe method. The pH of the solution is varied by using ammonia and hydrochloric acid. The comparative studies of effect of pH on the morphology, crystallanity and optoelectronic properties of the films are studied. It is observed that the pH of the solution has large influence on optoelectronic properties. The thin film prepared with neutral pH has higher crystallanity, bandgap and conductivity as compared to the samples prepared in acidic or basic solutions.

  10. Proceedings of the ICTSS 2012 PhD Workshop - Preface

    DEFF Research Database (Denmark)

    Nielsen, Brian; Weise, Carsten

    2012-01-01

    and their thesis work and receive constructive feedback from experts in the field as well as from peers. Also it is an opportunity for researchers to get an insight into new research topics in the field. Ph.D. students at any stage of their doctoral studies may participate. Seven abstracts were submitted......This technical report contains the proceedings of the Ph.D. Workshop held in conjunction with the The 24th IFIP Int. Conference on Testing Software and Systems (ICTSS'12) in Aalborg, Denmark, November 19, 2012. The well‐established ICTSS series of international conferences addresses the conceptual......, theoretic, and practical challenges of testing software systems, including communication protocols, services, distributed platforms, middleware, embedded systems, and security infrastructures. The aims of the ICTSS Doctoral Workshop is to provide a forum for PhD students to present preliminary results...

  11. A Multi-Parametric Device with Innovative Solid Electrodes for Long-Term Monitoring of pH, Redox-Potential and Conductivity in a Nuclear Waste Repository.

    Science.gov (United States)

    Daoudi, Jordan; Betelu, Stephanie; Tzedakis, Theodore; Bertrand, Johan; Ignatiadis, Ioannis

    2017-06-13

    We present an innovative electrochemical probe for the monitoring of pH, redox potential and conductivity in near-field rocks of deep geological radioactive waste repositories. The probe is composed of a monocrystalline antimony electrode for pH sensing, four AgCl/Ag-based reference or Cl - selective electrodes, one Ag₂S/Ag-based reference or S 2- selective electrode, as well as four platinum electrodes, a gold electrode and a glassy-carbon electrode for redox potential measurements. Galvanostatic electrochemistry impedance spectroscopy using AgCl/Ag-based and platinum electrodes measure conductivity. The use of such a multi-parameter probe provides redundant information, based as it is on the simultaneous behaviour under identical conditions of different electrodes of the same material, as well as on that of electrodes made of different materials. This identifies the changes in physical and chemical parameters in a solution, as well as the redox reactions controlling the measured potential, both in the solution and/or at the electrode/solution interface. Understanding the electrochemical behaviour of selected materials thus is a key point of our research, as provides the basis for constructing the abacuses needed for developing robust and reliable field sensors.

  12. Mobile Game Probes

    DEFF Research Database (Denmark)

    Borup Lynggaard, Aviaja

    2006-01-01

    This paper will examine how probes can be useful for game designers in the preliminary phases of a design process. The work is based upon a case study concerning pervasive mobile phone games where Mobile Game Probes have emerged from the project. The new probes are aimed towards a specific target...... group and the goal is to specify the probes so they will cover the most relevant areas for our project. The Mobile Game Probes generated many interesting results and new issues occurred, since the probes came to be dynamic and favorable for the process in new ways....

  13. Digestion products of the PH20 hyaluronidase inhibit remyelination.

    Science.gov (United States)

    Preston, Marnie; Gong, Xi; Su, Weiping; Matsumoto, Steven G; Banine, Fatima; Winkler, Clayton; Foster, Scott; Xing, Rubing; Struve, Jaime; Dean, Justin; Baggenstoss, Bruce; Weigel, Paul H; Montine, Thomas J; Back, Stephen A; Sherman, Larry S

    2013-02-01

    Oligodendrocyte progenitor cells (OPCs) recruited to demyelinating lesions often fail to mature into oligodendrocytes (OLs) that remyelinate spared axons. The glycosaminoglycan hyaluronan (HA) accumulates in demyelinating lesions and has been implicated in the failure of OPC maturation and remyelination. We tested the hypothesis that OPCs in demyelinating lesions express a specific hyaluronidase, and that digestion products of this enzyme inhibit OPC maturation. Mouse OPCs grown in vitro were analyzed for hyaluronidase expression and activity. Gain of function studies were used to define the hyaluronidases that blocked OPC maturation. Mouse and human demyelinating lesions were assessed for hyaluronidase expression. Digestion products from different hyaluronidases and a hyaluronidase inhibitor were tested for their effects on OPC maturation and functional remyelination in vivo. OPCs demonstrated hyaluronidase activity in vitro and expressed multiple hyaluronidases, including HYAL1, HYAL2, and PH20. HA digestion by PH20 but not other hyaluronidases inhibited OPC maturation into OLs. In contrast, inhibiting HA synthesis did not influence OPC maturation. PH20 expression was elevated in OPCs and reactive astrocytes in both rodent and human demyelinating lesions. HA digestion products generated by the PH20 hyaluronidase but not another hyaluronidase inhibited remyelination following lysolecithin-induced demyelination. Inhibition of hyaluronidase activity lead to increased OPC maturation and promoted increased conduction velocities through lesions. We determined that PH20 is elevated in demyelinating lesions and that increased PH20 expression is sufficient to inhibit OPC maturation and remyelination. Pharmacological inhibition of PH20 may therefore be an effective way to promote remyelination in multiple sclerosis and related conditions. Copyright © 2012 American Neurological Association.

  14. Timing system design and tests for the Gravity Probe B relativity mission

    International Nuclear Information System (INIS)

    Li, J; Keiser, G M; Ohshima, Y; Shestople, P; Lockhart, J M

    2015-01-01

    In this paper, we discuss the timing system design and tests for the NASA/Stanford Gravity Probe B (GP-B) relativity mission. The primary clock of GP-B, called the 16f o clock, was an oven-controlled crystal oscillator that produced a 16.368 MHz master frequency 3 . The 16f o clock and the 10 Hz data strobe, which was divided down from the 16f o clock, provided clock signals to all GP-B components and synchronized the data collection, transmission, and processing. The sampled data of science signals were stamped with the vehicle time, a counter of the 10 Hz data strobe. The time latency between the time of data sampling and the stamped vehicle time was compensated in the ground data processing. Two redundant global positioning system receivers onboard the GP-B satellite supplied an external reference for time transfer between the vehicle time and coordinated universal time (UTC), and the time conversion was established in the ground preprocessing of the telemetry timing data. The space flight operation showed that the error of time conversion between the vehicle time and UTC was less than 2 μs. Considering that the constant timing offsets were compensated in the ground processing of the GP-B science data, the time latency between the effective sampling time of GP-B science signals and the stamped vehicle time was verified to within 1 ms in the ground tests. (paper)

  15. Experimental and theoretical evaluation of nanodiamonds as pH triggered drug carriers

    KAUST Repository

    Yan, Jingjing

    2012-01-01

    Nanodiamond (ND) and its derivatives have been widely used for drug, protein and gene delivery. Herein, experimental and theoretical methods have been combined to investigate the effect of pH on the delivery of doxorubicin (DOX) from fluorescein labeled NDs (Fc-NDs). In the endosomal recycling process, the nanoparticle will pass from mildly acidic vesicle to pH ≈ 4.8; thus, it is important to investigate DOX release from NDs at different pH values. Fc-NDs released DOX dramatically under acidic conditions, while an increase in the DOX loading efficiency (up to 6.4 wt%) was observed under basic conditions. Further theoretical calculations suggest that H + weakens the electrostatistic interaction between ND surface carboxyl groups and DOX amino groups, and the interaction energies at pH < 7, pH 7 and pH > 7 are 10.4 kcal mol -1, 25.0 kcal mol -1 and 27.0 kcal mol -1 respectively. Cellular imaging experiments show that Fc-NDs are readily ingested by breast adenocarcinoma (BA) cells and cell viability tests prove that they can be utilized as a safe drug delivery vehicle. Furthermore, pH triggered DOX release has been tested in vitro (pH 7.4 and pH 4.83) in breast adenocarcinoma (BA) cells. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.

  16. Traversing probe system

    Science.gov (United States)

    Mashburn, Douglas N.; Stevens, Richard H.; Woodall, Harold C.

    1977-01-01

    This invention comprises a rotatable annular probe-positioner which carries at least one radially disposed sensing probe, such as a Pitot tube having a right-angled tip. The positioner can be coaxially and rotatably mounted within a compressor casing or the like and then actuated to orient the sensing probe as required to make measurements at selected stations in the annulus between the positioner and compressor casing. The positioner can be actuated to (a) selectively move the probe along its own axis, (b) adjust the yaw angle of the right-angled probe tip, and (c) revolve the probe about the axis common to the positioner and casing. A cam plate engages a cam-follower portion of the probe and normally rotates with the positioner. The positioner includes a first-motor-driven ring gear which effects slidable movement of the probe by rotating the positioner at a time when an external pneumatic cylinder is actuated to engage the cam plate and hold it stationary. When the pneumatic cylinder is not actuated, this ring gear can be driven to revolve the positioner and thus the probe to a desired circumferential location about the above-mentioned common axis. A second motor-driven ring gear included in the positioner can be driven to rotate the probe about its axis, thus adjusting the yaw angle of the probe tip. The positioner can be used in highly corrosive atmosphere, such as gaseous uranium hexafluoride.

  17. Traversing probe system

    International Nuclear Information System (INIS)

    Mashburn, D.N.; Stevens, R.H.; Woodall, H.C.

    1977-01-01

    This invention comprises a rotatable annular probe-positioner which carries at least one radially disposed sensing probe, such as a Pitot tube having a right-angled tip. The positioner can be coaxially and rotatably mounted within a compressor casing or the like and then actuated to orient the sensing probe as required to make measurements at selected stations in the annulus between the positioner and compressor casing. The positioner can be actuated to (a) selectively move the probe along its own axis, (b) adjust the yaw angle of the right-angled probe tip, and (c) revolve the probe about the axis common to the positioner and casing. A cam plate engages a cam-follower portion of the probe and normally rotates with the positioner. The positioner includes a first-motor-driven ring gear which effects slidable movement of the probe by rotating the positioner at a time when an external pneumatic cylinder is actuated to engage the cam plate and hold it stationary. When the pneumatic cylinder is not actuated, this ring gear can be driven to revolve the positioner and thus the probe to a desired circumferential location about the above-mentioned common axis. A second motor-driven ring gear included in the positioner can be driven to rotate the probe about its axis, thus adjusting the yaw angle of the probe tip. The positioner can be used in highly corrosive atmosphere, such as gaseous uranium hexafluoride. 10 claims, 6 figures

  18. Ocean Health X-Prize testing of a Simplified Spectrophotometric pH Sensor

    Science.gov (United States)

    Darlington, R. C.; DeGrandpre, M. D.; Spaulding, R. S.; Beck, J. C.

    2016-02-01

    Since the Industrial Revolution, the world's oceans have absorbed increasing amounts of CO2, resulting in a >0.1 reduction in the pH of surface waters. This acidification of the oceans has many far reaching impacts on marine life. There is, therefore, great need of quality instrumentation to assess and follow the changing carbonate system. To address this need, we have developed a simplified spectrophotometric pH sensor with accuracy and precision suitable for sea surface measurements with special emphasis on reduced size and cost. The reduced size will allow deployment of sensors on a much wider variety of platforms than are currently possible, and the reduced cost will make the instruments available to a broader research community. This prototype pH instrument was entered into the Wendy Schmidt Ocean Health X-Prize, an incentivized global competition to spur innovation in sensors to monitor ocean acidification's impact on marine ecosystems. Results from the three phases of competition which explored accuracy, precision, and stability culminating in a one month field trial are detailed. The prototype proved to be highly accurate (+/-0.009), with good precision (+/-0.004) and stability showing drift indistinguishable from that of the validation measurements. The innovations that enabled this sensor to succeed in the competition could allow for deployment of spectrophotometric sensors on new platforms such as NOAAs Global Drifter Program, a network of non-recovered surface drifting buoys, which would greatly extend the spatial and temporal resolution of ocean acidification measurements.

  19. Influence of probe geometry on the response of an electrostatic probe

    DEFF Research Database (Denmark)

    Johansson, Torben; Crichton, George C; McAllister, Iain Wilson

    1999-01-01

    The response of an electrostatic probe is examined with reference to the probe geometry. The study involves the evaluation of the probe lambda function, from which response-related characteristic parameters can be derived. These parameters enable the probe detection sensitivity Se and spatial...

  20. Evaluation of a flow direction probe and a pitot-static probe on the F-14 airplane at high angles of attack and sideslip

    Science.gov (United States)

    Larson, T. J.

    1984-01-01

    The measurement performance of a hemispherical flow-angularity probe and a fuselage-mounted pitot-static probe was evaluated at high flow angles as part of a test program on an F-14 airplane. These evaluations were performed using a calibrated pitot-static noseboom equipped with vanes for reference flow direction measurements, and another probe incorporating vanes but mounted on a pod under the fuselage nose. Data are presented for angles of attack up to 63, angles of sideslip from -22 deg to 22 deg, and for Mach numbers from approximately 0.3 to 1.3. During maneuvering flight, the hemispherical flow-angularity probe exhibited flow angle errors that exceeded 2 deg. Pressure measurements with the pitot-static probe resulted in very inaccurate data above a Mach number of 0.87 and exhibited large sensitivities with flow angle.

  1. The Probe of Inflation and Cosmic Origins

    Science.gov (United States)

    Hanany, Shaul; Inflation Probe Mission Study Team

    2018-01-01

    The Probe of Inflation and Cosmic Origins will map the polarization of the cosmic microwave background over the entire sky with unprecedented sensitivity. It will search for gravity wave signals from the inflationary epoch, thus probing quantum gravity and constraining the energy scale of inflation; it will test the standard model of particle physics by measuring the number of light particles in the Universe and the mass of the neutrino; it will elucidate the nature of dark matter and search for new forms of matter in the early Universe; it will constrain star formation history over cosmic time; and it will determine the mechanisms of structure formation from galaxy cluster to stellar scales. I will review the status of design of this probe-scale mission.

  2. Quality control devices for intraoperative gamma probes: physical, technical and radiation protection aspects

    International Nuclear Information System (INIS)

    Varela, C.; Diaz, M.; Salvador, F.J.; Hernandez, M.; Jimenez, P.

    2008-01-01

    Now a day, radio guided surgery -a novelty in Nuclear Medicine- is increasingly used. The clinical efficiency of these procedures requires the existence of well-trained professionals and implementation of quality assurance programs. It is essential for achieving the main objective, which is an effective and safe surgical procedure, a reliable performance of the detection device. Probes' parameters must remain within the acceptance limits, so they should be checked periodically. NEMA Standards Publication NU 3-2004 'Performance Measurement and Quality Control Guidelines for Non-Imaging Intraoperative Gamma Probes' recommends 13 tests; although only 3 of them -sensibility in air, visual inspection and power source check- are considered as steadiness tests. Space resolution in a scatter medium is also a test that needs to be carried out. These tests are considerably complex since open radioactive sources are used into a liquid medium in most of the procedures. The immersion of the probe and of the radioactive sources in each case represents both risks of radioactive contamination, and of damages to the equipment. On the other hand, tests in air demand a good reproducibility. Since they are recommended be carried out before any surgery procedure, they also should be easy and quick. This paper presents 3 devices with its accessories for acceptance and quality control tests of intraoperative gamma probes. They were designed and built taking into consideration important aspects of radiological protection to handle the calibration sources and probes, both in air and into a scatter medium. These devices are designed to fit any kind of probe. Regulatory bodies as part of their instrument audits can also use them. (author)

  3. Hydrogen-Helium shock Radiation tests for Saturn Entry Probes

    Science.gov (United States)

    Cruden, Brett A.

    2016-01-01

    This paper describes the measurement of shock layer radiation in Hydrogen/Helium mixtures representative of that encountered by probes entering the Saturn atmosphere. Normal shock waves are measured in Hydrogen-Helium mixtures (89:11% by volume) at freestream pressures between 13-66 Pa (0.1-0.5 Torr) and velocities from 20-30 km/s. Radiance is quantified from the Vacuum Ultraviolet through Near Infrared. An induction time of several centimeters is observed where electron density and radiance remain well below equilibrium. Radiance is observed in front of the shock layer, the characteristics of which match the expected diffusion length of Hydrogen.

  4. Brain parenchyma PO2, PCO2, and pH during and after hypoxic, ischemic brain insult in dogs.

    Science.gov (United States)

    McKinley, B A; Morris, W P; Parmley, C L; Butler, B D

    1996-11-01

    1) The investigation of fiberoptic PO2, PCO2, and pH sensor technology as a monitor of brain parenchyma during and after brain injury, and 2) the comparison of brain parenchyma PO2, PCO2, and pH with intracranial pressure during and after hypoxic, ischemic brain insult. Prospective, controlled, animal study in an acute experimental preparation. Physiology laboratory in a university medical school. Fourteen mongrel dogs (20 to 35 kg), anesthetized, room-air ventilated. Anesthesia was induced with thiopental and maintained after intubation using 1% to 1.5% halothane in room air (FiO2 0.21). Mechanical ventilation was established to maintain end-tidal PCO2 approximately 35 torr (-4.7 kPa). Intravenous, femoral artery, and pulmonary artery catheters were placed. The common carotid arteries were surgically exposed, and ultrasonic blood flow probes were applied. A calibrated intracranial pressure probe was placed through a right-side transcranial bolt, and a calibrated intracranial chemistry probe with optical sensors for PO2, PCO2, and pH was placed through a left-side bolt into brain parenchyma. Brain insult was induced in the experimental group (n = 6) by hypoxia (FiO2 0.1), ischemia (bilateral carotid artery occlusion), and hypotension (mean arterial pressure [MAP] approximately 40 mm Hg produced with isoflurane approximately 4%). After 45 mins, carotid artery occlusion was released, FiO2 was reset to 0.21, and anesthetic was returned to halothane (approximately 1.25%). The control group (n = 5) had the same surgical preparation and sequence of anesthetic agent exposure but no brain insult. Monitored variables included brain parenchyma PO2, PCO2, and pH, which were monitored at 1-min intervals, and intracranial pressure, MAP, arterial hemoglobin oxygen saturation (by pulse oximetry), end-tidal PCO2, and carotid artery blood flow rate, for which data were collected at 15-min intervals for 7 hrs. Arterial and mixed venous blood gas analyses were done at approximately 1

  5. Determining pH at elevated pressure and temperature using in situ ¹³C NMR.

    Science.gov (United States)

    Surface, J Andrew; Wang, Fei; Zhu, Yanzhe; Hayes, Sophia E; Giammar, Daniel E; Conradi, Mark S

    2015-02-03

    We have developed an approach for determining pH at elevated pressures and temperatures by using (13)C NMR measurements of inorganic carbon species together with a geochemical equilibrium model. The approach can determine in situ pH with precision better than 0.1 pH units at pressures, temperatures, and ionic strengths typical of geologic carbon sequestration systems. A custom-built high pressure NMR probe was used to collect (13)C NMR spectra of (13)C-labeled CO2 reactions with NaOH solutions and Mg(OH)2 suspensions at pressures up to 107 bar and temperatures of 80 °C. The quantitative nature of NMR spectroscopy allows the concentration ratio [CO2]/[HCO3(-)] to be experimentally determined. This ratio is then used with equilibrium constants calculated for the specific pressure and temperature conditions and appropriate activity coefficients for the solutes to calculate the in situ pH. The experimentally determined [CO2]/[HCO3(-)] ratios agree well with the predicted values for experiments performed with three different concentrations of NaOH and equilibration with multiple pressures of CO2. The approach was then applied to experiments with Mg(OH)2 slurries in which the change in pH could track the dissolution of CO2 into solution, rapid initial Mg(OH)2 dissolution, and onset of magnesium carbonate precipitation.

  6. Is Your Drinking Water Acidic? A Comparison of the Varied pH of Popular Bottled Waters.

    Science.gov (United States)

    Wright, Kellie F

    2015-06-01

    Dental professionals continually educate patients on the dangers of consuming acidic foods and beverages due to their potential to contribute to dental erosion and tooth decay. Excess acid in the diet can also lead to acidosis, which causes negative systemic side effects. However, water is not typically categorized as acidic. The purpose of this in-vitro study was to investigate the pH levels of several popular brands of bottled water and compare them to various other acidic beverages. Two different brands of marketed alkaline water (with a pH of 8.8 or higher) were also studied, tested for acidity and described. A pilot in-vitro study was conducted to determine the pH levels of a convenience sample of popular brands of bottled water, tap water and other known acidic beverages in comparison with the pH values reported on the respective manufacturers' website. Each beverage was tested in a laboratory using a calibrated Corning pH meter model 240, and waters were compared to the corresponding company's testified pH value. Waters were also compared and contrasted based on their process of purification. The data was then compiled and analyzed descriptively. The pH values for the tested beverages and bottled waters were found to be predominantly acidic. Ten out of the 14 beverages tested were acidic (pHwaters were neutral (pH=7) and 2 bottled waters were alkaline (pH>7). The majority of waters tested had a more acidic pH when tested in the lab than the value listed in their water quality reports. It is beneficial for the health care provider to be aware of the potential acidity of popular bottled drinking waters and educate patients accordingly. Copyright © 2015 The American Dental Hygienists’ Association.

  7. Increased vaginal pH in Ugandan women: what does it indicate?

    Science.gov (United States)

    Donders, G G G; Gonzaga, A; Marconi, C; Donders, F; Michiels, T; Eggermont, N; Bellen, G; Lule, J; Byamughisa, J

    2016-08-01

    Abnormal vaginal flora (AVF), indicative of bacterial vaginosis (BV) and/or aerobic vaginitis (AV), amongst other abnormalities, is a risk factor for multiple complications in pregnant as well as non-pregnant women. Screening for such conditions could help prevent these complications. Can self-testing for increased vaginal pH reliably detect BV and other high-risk microflora types, and is this more accurate than performing Gram stain-based Nugent score when screening for high-risk microflora? A total of 344 women presenting at different outpatient clinics in Mulago Hospital and Mbuikwe Outpatient clinics in Kampala, Uganda, were asked to test themselves by introducing a gloved finger into the vagina and smearing it on a microscopy slide, on which a pH strip was attached. Self-assessed categories of normal (pH 3.6-4.4), intermediate (4.5-4.7) or high pH (>4.7) were compared with demographic and with centralised microscopic data, both in air-dried rehydrated wet mounts (Femicare), as well as in Gram-stained specimens (Nugent). AVF was present in 38 %, BV in 25 % and AV in 11 % of patients. High pH and AVF is correlated with human immunodeficiency virus (HIV), infertility, frequent sex, but not vaginal douching. Screening for raised pH detects 90 % of AVF cases, but would require testing over half of the population. As AV and non-infectious conditions are frequent in women with AVF and high pH, Nugent score alone is an insufficient technique to screen women for a high-risk vaginal microflora, especially in infertile and HIV-infected women.

  8. Highly specific detection of genetic modification events using an enzyme-linked probe hybridization chip.

    Science.gov (United States)

    Zhang, M Z; Zhang, X F; Chen, X M; Chen, X; Wu, S; Xu, L L

    2015-08-10

    The enzyme-linked probe hybridization chip utilizes a method based on ligase-hybridizing probe chip technology, with the principle of using thio-primers for protection against enzyme digestion, and using lambda DNA exonuclease to cut multiple PCR products obtained from the sample being tested into single-strand chains for hybridization. The 5'-end amino-labeled probe was fixed onto the aldehyde chip, and hybridized with the single-stranded PCR product, followed by addition of a fluorescent-modified probe that was then enzymatically linked with the adjacent, substrate-bound probe in order to achieve highly specific, parallel, and high-throughput detection. Specificity and sensitivity testing demonstrated that enzyme-linked probe hybridization technology could be applied to the specific detection of eight genetic modification events at the same time, with a sensitivity reaching 0.1% and the achievement of accurate, efficient, and stable results.

  9. Meet EPA Scientist Jeff Szabo, Ph.D.

    Science.gov (United States)

    EPA scientist Jeff Szabo, Ph.D., has worked for the EPA’s National Homeland Security Research Center since 2005. He conducts and manages water security research projects at EPA’s Test and Evaluation facility.

  10. Dimensioning of optimal probe circuits for the non-destructive testing of materials by eddy-current using Buschbeck-Meinke chart

    International Nuclear Information System (INIS)

    Ott, A.

    1982-01-01

    By application of a modified form of the Buschbeck-Meinke-diagram, known from conduction theory, easy-to use dimensioning rules can be given for the probe circuits of single-frequency eddy-current test instruments. Dimensioning is found for circuits that work with amplitude or phase measurements, that suppress optimal the disturbance parameters in certain regions. In a similar way one can determine dimensioning, with which the measurement quantity causes the highest possible signal charge. (orig.) [de

  11. Synthesis and photophysical properties of a novel terephthalic PH sensor based on internal charge transfer

    International Nuclear Information System (INIS)

    Miladinova, Polya M.

    2016-01-01

    A novel fluorescence sensing derivative of 2-aminodimethylterephthalate configured as a “fluorophore-receptor” system was synthesized and investigated. Due to the internal charge transfer, the designed fluorophore was able to act as a pH-probe via an “off-on” fluorescence sensing mechanism. The sensor activity toward protons as cations and hydroxide as anions in DMF was studied by monitoring the changes of the fluorescence intensity. Keywords: 2-aminoterephthalic derivative, ICT (internal charge transfer), pH sensor.

  12. Influence of pH on extracellular matrix preservation during lung decellularization.

    Science.gov (United States)

    Tsuchiya, Tomoshi; Balestrini, Jenna L; Mendez, Julio; Calle, Elizabeth A; Zhao, Liping; Niklason, Laura E

    2014-12-01

    The creation of decellularized organs for use in regenerative medicine requires the preservation of the organ extracellular matrix (ECM) as a means to provide critical cues for differentiation and migration of cells that are seeded onto the organ scaffold. The purpose of this study was to assess the influence of varying pH levels on the preservation of key ECM components during the decellularization of rat lungs. Herein, we show that the pH of the 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS)-based decellularization solution influences ECM retention, cell removal, and also the potential for host response upon implantation of acellular lung tissue. The preservation of ECM components, including elastin, fibronectin, and laminin, were better retained in the lower pH conditions that were tested (pH ranges tested: 8, 10, 12); glycosaminoglycans were preserved to a higher extent in the lower pH groups as well. The DNA content following decellularization of the rat lung was inversely correlated with the pH of the decellularization solution. Despite detectible levels of cyotoskeletal proteins and significant residual DNA, tissues decellularized at pH 8 demonstrated the greatest tissue architecture maintenance and the least induction of host response of all acellular conditions. These results highlight the effect of pH on the results obtained by organ decellularization and suggest that altering the pH of the solutions used for decellularization may influence the ability of cells to properly differentiate and home to appropriate locations within the scaffold, based on the preservation of key ECM components and implantation results.

  13. The magnetic-distortion probe: velocimetry in conducting fluids.

    Science.gov (United States)

    Miralles, Sophie; Verhille, Gautier; Plihon, Nicolas; Pinton, Jean-François

    2011-09-01

    A new type of velocimeter, capable of local velocity measurements in conducting fluids, is introduced. The principle of the "magnetic-distortion probe" is based on the measurement of the induced magnetic field by the flow of a conducting fluid in the vicinity of a localized magnetic field. The new velocimeter has no moving parts, and can be enclosed in a sealed cap, easing the implementation in harsh environments, such as liquid metals. The proposed method allows one to probe both the continuous part and fluctuations of the velocity, the temporal and spatial resolution being linked to the actual geometric configuration of the probe. A prototype probe has been tested in a gallinstan pipe flow and in a fully turbulent flow of liquid gallium generated by the counter rotation of two coaxial impellers in a cylinder. The signals have been compared to a reference potential probe and show very good agreement both for time-averaged velocities and turbulent fluctuations. The prototype is shown to detect motion from a few cm s(-1) to a few m s(-1). Moreover, the use of the magnetic-distortion probe with large-scale applied magnetic field is discussed. © 2011 American Institute of Physics

  14. [Alpha but not beta-adrenergic stimulation has a positive inotropic effect associated with alkalinization of intracellular pH].

    Science.gov (United States)

    Gambassi, G; Lakatta, E G; Capogrossi, M C

    1991-01-01

    There is increasing evidence that alpha-adrenoceptors also exist in the myocardium and that an increase in force of contraction may be produced by stimulation of these sites. This positive inotropism seems to be dependent either on an increased amount of Ca++ released into the cytosol with each action potential or on increased myofilament responsiveness. In contrast, beta-adrenergic stimulation reduces the sensitivity of the contractile proteins and the positive inotropic effect is due to the activation of L-type calcium channels on the sarcolemma. We used single, isolated, enzymatically dissociated, adult rat ventricular myocytes. Cells were loaded either with the ester derivative of the Ca++ probe Indo-1 or with the intracellular pH probe Snarf-1 and at the same time we measured the contractile parameters and monitored the fluorescence as an index of intracellular calcium concentration or pH value. The single cells (bicarbonate buffer continuously gassed with O2 95%, CO2 5%, Ca++ 1.5 mM, field stimulation 0.5 Hz) were exposed to phenylephrine (50 microM) and nadolol (1 microM). Alpha-adrenergic stimulation increased twitch amplitude (delta ES = 1.93 +/- 0.77, n = 8; p less than 0.05) and showed only a slight increase in Ca++ transient. On the other end, the positive inotropic effect (delta ES = 2.84 +/- 0.86, n = 4; p less than 0.02) obtained with beta-adrenergic stimulation (isoproterenol 50 nM, bicarbonate buffer, Ca++ 0.5 mM, field stimulation 0.2 Hz) was always associated with a large increase in intracellular Ca++ concentration. Isoproterenol did not change intracellular pH (delta pH = 0.006 +/- 0.006, n = 4; NS) while phenylephrine increased it significantly (delta pH = 0.055 +/- 0.011, n = 8; p less than 0.002). Moreover, there was a statistically significant correlation between delta ES and delta pH (R2 = 0.532; p less than 0.05) when phenylephrine was present. This alkalinization as well as the increased contractility was antagonized by treatment with

  15. Chemical Probes of Histone Lysine Methyltransferases

    Science.gov (United States)

    2015-01-01

    Growing evidence suggests that histone methyltransferases (HMTs, also known as protein methyltransferases (PMTs)) play an important role in diverse biological processes and human diseases by regulating gene expression and the chromatin state. Therefore, HMTs have been increasingly recognized by the biomedical community as a class of potential therapeutic targets. High quality chemical probes of HMTs, as tools for deciphering their physiological functions and roles in human diseases and testing therapeutic hypotheses, are critical for advancing this promising field. In this review, we focus on the discovery, characterization, and biological applications of chemical probes for HMTs. PMID:25423077

  16. The Oxford Probe: an open access five-hole probe for aerodynamic measurements

    Science.gov (United States)

    Hall, B. F.; Povey, T.

    2017-03-01

    The Oxford Probe is an open access five-hole probe designed for experimental aerodynamic measurements. The open access probe can be manufactured by the end user via additive manufacturing (metal or plastic). The probe geometry, drawings, calibration maps, and software are available under a creative commons license. The purpose is to widen access to aerodynamic measurement techniques in education and research environments. There are many situations in which the open access probe will allow results of comparable accuracy to a well-calibrated commercial probe. We discuss the applications and limitations of the probe, and compare the calibration maps for 16 probes manufactured in different materials and at different scales, but with the same geometrical design.

  17. The Oxford Probe: an open access five-hole probe for aerodynamic measurements

    International Nuclear Information System (INIS)

    Hall, B F; Povey, T

    2017-01-01

    The Oxford Probe is an open access five-hole probe designed for experimental aerodynamic measurements. The open access probe can be manufactured by the end user via additive manufacturing (metal or plastic). The probe geometry, drawings, calibration maps, and software are available under a creative commons license. The purpose is to widen access to aerodynamic measurement techniques in education and research environments. There are many situations in which the open access probe will allow results of comparable accuracy to a well-calibrated commercial probe. We discuss the applications and limitations of the probe, and compare the calibration maps for 16 probes manufactured in different materials and at different scales, but with the same geometrical design. (paper)

  18. Evaluation of water cooled supersonic temperature and pressure probes for application to 2000 F flows

    Science.gov (United States)

    Lagen, Nicholas T.; Seiner, John M.

    1990-01-01

    The development of water cooled supersonic probes used to study high temperature jet plumes is addressed. These probes are: total pressure, static pressure, and total temperature. The motivation for these experiments is the determination of high temperature supersonic jet mean flow properties. A 3.54 inch exit diameter water cooled nozzle was used in the tests. It is designed for exit Mach 2 at 2000 F exit total temperature. Tests were conducted using water cooled probes capable of operating in Mach 2 flow, up to 2000 F total temperature. Of the two designs tested, an annular cooling method was chosen as superior. Data at the jet exit planes, and along the jet centerline, were obtained for total temperatures of 900 F, 1500 F, and 2000 F, for each of the probes. The data obtained from the total and static pressure probes are consistent with prior low temperature results. However, the data obtained from the total temperature probe was affected by the water coolant. The total temperature probe was tested up to 2000 F with, and without, the cooling system turned on to better understand the heat transfer process at the thermocouple bead. The rate of heat transfer across the thermocouple bead was greater when the coolant was turned on than when the coolant was turned off. This accounted for the lower temperature measurement by the cooled probe. The velocity and Mach number at the exit plane and centerline locations were determined from the Rayleigh-Pitot tube formula.

  19. Probe Techniques. Introductory Remarks

    Energy Technology Data Exchange (ETDEWEB)

    Emeleus, K. G. [School of Physics and Applied Mathematics, Queen' s University, Belfast (United Kingdom)

    1968-04-15

    In this brief introduction to the session on probes, the history of theii development is first touched on briefly. Reference is then made to the significance of the work to be described by Medicus, for conductivity and recombination calculations, and by Lam and Su, for a wide range of medium and higher pressure plasmas. Finally, a number of other probe topics are mentioned, including multiple probes; probes in electronegative plasmas; resonance probes; probes in noisy discharges; probes as oscillation detectors; use of probes where space-charge is not negligible. (author)

  20. Developments in quantitative electron probe microanalysis

    International Nuclear Information System (INIS)

    Tixier, R.

    1977-01-01

    A study of the range of validity of the formulae for corrections used with massive specimen analysis is made. The method used is original; we have shown that it was possible to use a property of invariability of corrected intensity ratios for standards. This invariance property provides a test for the self consistency of the theory. The theoretical and experimental conditions required for quantitative electron probe microanalysis of thin transmission electron microscope specimens are examined. The correction formulae for atomic number, absorption and fluorescence effects are calculated. Several examples of experimental results are given, relative to the quantitative analysis of intermetallic precipitates and carbides in steels. Advances in applications of electron probe instruments related to the use of computer and the present development of fully automated instruments are reviewed. The necessary statistics for measurements of X ray count data are studied. Estimation procedure and tests are developed. These methods are used to perform a statistical check of electron probe microanalysis measurements and to reject rogue values. An estimator of the confidence interval of the apparent concentration is derived. Formulae were also obtained to optimize the counting time in order to obtain the best precision in a minimum amount of time [fr

  1. Probe-diverse ptychography

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, I., E-mail: isaac.russellpeterson@rmit.edu.au [ARC Centre of Excellence for Coherent X-ray Science, the University of Melbourne, School of Physics, Victoria 3010 (Australia); Harder, R. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Robinson, I.K. [Research Complex at Harwell, Didcot, Oxfordshire OX11 0DE (United Kingdom); London Centre for Nanotechnology, University College London, London WC1H 0AH (United Kingdom)

    2016-12-15

    We propose an extension of ptychography where the target sample is scanned separately through several probes with distinct amplitude and phase profiles and a diffraction image is recorded for each probe and each sample translation. The resulting probe-diverse dataset is used to iteratively retrieve high-resolution images of the sample and all probes simultaneously. The method is shown to yield significant improvement in the reconstructed sample image compared to the image obtained using the standard single-probe ptychographic phase-retrieval scheme.

  2. Corrosion of glass-bonded sodalite as a function of pH and temperature

    International Nuclear Information System (INIS)

    Morss, L. R.; Stanley, M.; Tatko, C.; Ebert, W. L.

    1999-01-01

    This paper reports the results of corrosion tests with monoliths of sodalite, binder glass, and glass-bonded sodalite, a ceramic waste form (CWF) that is being developed to immobilize radioactive electrorefiner salt used to condition spent sodium-bonded nuclear fuel. These tests were performed with dilute pH-buffered solutions in the pH range of 5-10 at temperatures of 70 and 90 C. The pH dependence of the forward dissolution rates of the CWF and its components have been determined. The pH dependence of the dissolution rates of sodalite, binder glass, and glass-bonded sodalite are similar to the pH dependence of dissolution rate of borosilicate nuclear waste glasses, with a negative pH dependence in the acidic region and a positive pH dependence in the basic region. Our results on the forward dissolution rates and their temperature and pH dependence will be used as components of a waste form degradation model to predict the long-term behavior of the CWF in a nuclear waste repository

  3. Design and performance of low-wattage electrical heater probe

    International Nuclear Information System (INIS)

    Biddle, R.; Wetzel, J.R.; Cech, R.

    1997-01-01

    A mound electrical calibration heater (MECH) has been used in several EG and G Mound developed calorimeters as a calibration tool. They are very useful over the wattage range of a few to 500 W. At the lower end of the range, a bias develops between the MECH probe and calibrated heat standards. A low-wattage electrical calibration heater (L WECH) probe is being developed by the Safeguards Science and Technology group (NIS-5) of Los Alamos National Laboratory based upon a concept proposed by EG and G Mound personnel. The probe combines electrical resistive heating and laser-light powered heating. The LWECH probe is being developed for use with power settings up to 2W. The electrical heater will be used at the high end of the range, and laser-light power will be used low end of the wattage range. The system consists of two components: the heater probe and a control unit. The probe is inserted into the measuring cavity through an opening in the insulating baffle, and a sleeve is required to adapt to the measuring chamber. The probe is powered and controlled using electronics modules located separately. This paper will report on the design of the LWECH probe, initial tests, and expected performance

  4. Calorimeter probes for measuring high thermal flux. [in arc jets

    Science.gov (United States)

    Russell, L. D.

    1979-01-01

    Expendable, slug-type calorimeter probes were developed for measuring high heat-flux levels of 10-30 kW/sq cm in electric-arc jet facilities. The probes were constructed with thin tungsten caps mounted on Teflon bodies. The temperature of the back surface of the tungsten cap is measured, and its time rate of change gives the steady-state absorbed heat flux as the calorimeter probe heats to destruction when inserted into the arc jet. Design, construction, test, and performance data are presented.

  5. Design of piezoelectric probe for measurement of longitudinal and shear components of elastic wave

    Science.gov (United States)

    Aoyanagi, Masafumi; Wakatsuki, Naoto; Mizutani, Koichi; Ebihara, Tadashi

    2017-07-01

    We focus on ultrasonic probes for nondestructive tests and evaluation. Transient characteristics of probes are important for nondestructive tests such as the pulse echo method. We previously reported the principle of measurement using a piezoelectric probe with triaxial sensitivities. In the results, it was calculated that the probe could transmit and receive particle displacement which contains normal and tangential components. It was confirmed that the probe had sensitivities in triaxial directions. However, its performance in terms of frequency and transient characteristics has not been evaluated. The purpose of this study is to design a probe by changing its shape to obtain better performance. The transient characteristics of probes in longitudinal and shear driving were evaluated by the inverse Fourier transformation of frequency responses of longitudinal and shear components, using the two-dimensional finite element method. As a result, the sensitivities at the dips of frequency characteristics increased when using our probe compared with those measured using conventional probes in longitudinal and shear driving. Hence, the performance in terms of the frequency response was improved by more than 3 dB under the conditions in this simulation. Also, the pulse width of impulse response was decreased by half compared with that of probes with conventional shapes.

  6. Flexible poly(methyl methacrylate)-based neural probe: An affordable implementation

    Science.gov (United States)

    Gasemi, Pejman; Veladi, Hadi; Shahabi, Parviz; Khalilzadeh, Emad

    2018-03-01

    This research presents a novel technique used to fabricate a deep brain stimulation probe based on a commercial poly(methyl methacrylate) (PMMA) polymer. This technique is developed to overcome the high cost of available probes crucial for chronic stimulation and recording in neural disorders such as Parkinson’s disease and epilepsy. The probe is made of PMMA and its mechanical properties have been customized by controlling the reaction conditions. The polymer is adjusted to be stiff enough to be easily inserted and, on the other hand, soft enough to perform required movements. As cost is one of the issues in the use of neural probes, a simple process is proposed for the production of PMMA neural probes without using expensive equipment and operations, and without compromising performance and quality. An in vivo animal test was conducted to observe the recording capability of a PMMA probe.

  7. Neutral helium beam probe

    Science.gov (United States)

    Karim, Rezwanul

    1999-10-01

    This article discusses the development of a code where diagnostic neutral helium beam can be used as a probe. The code solves numerically the evolution of the population densities of helium atoms at their several different energy levels as the beam propagates through the plasma. The collisional radiative model has been utilized in this numerical calculation. The spatial dependence of the metastable states of neutral helium atom, as obtained in this numerical analysis, offers a possible diagnostic tool for tokamak plasma. The spatial evolution for several hypothetical plasma conditions was tested. Simulation routines were also run with the plasma parameters (density and temperature profiles) similar to a shot in the Princeton beta experiment modified (PBX-M) tokamak and a shot in Tokamak Fusion Test Reactor tokamak. A comparison between the simulation result and the experimentally obtained data (for each of these two shots) is presented. A good correlation in such comparisons for a number of such shots can establish the accurateness and usefulness of this probe. The result can possibly be extended for other plasma machines and for various plasma conditions in those machines.

  8. Early warning smartphone diagnostics for water security and analysis using real-time pH mapping

    Science.gov (United States)

    Hossain, Md. Arafat; Canning, John; Ast, Sandra; Rutledge, Peter J.; Jamalipour, Abbas

    2015-12-01

    Early detection of environmental disruption, unintentional or otherwise, is increasingly desired to ensure hazard minimization in many settings. Here, using a field-portable, smartphone fluorimeter to assess water quality based on the pH response of a designer probe, a map of pH of public tap water sites has been obtained. A custom designed Android application digitally processed and mapped the results utilizing the global positioning system (GPS) service of the smartphone. The map generated indicates no disruption in pH for all sites measured, and all the data are assessed to fall inside the upper limit of local government regulations, consistent with authority reported measurements. This implementation demonstrates a new security concept: network environmental forensics utilizing the potential of novel smartgrid analysis with wireless sensors for the detection of potential disruption to water quality at any point in the city. This concept is applicable across all smartgrid strategies within the next generation of the Internet of Things and can be extended on national and global scales to address a range of target analytes, both chemical and biological.

  9. The Sheath-less Planar Langmuir Probe

    Science.gov (United States)

    Cooke, D. L.

    2017-12-01

    The Langmuir probe is one of the oldest plasma diagnostics, provided the plasma density and species temperature from analysis of a current-voltage curve as the voltage is swept over a practically chosen range. The analysis depends on a knowledge or theory of the many factors that influence the current-voltage curve including, probe shape, size, nearby perturbations, and the voltage reference. For applications in Low Earth Orbit, the Planar Langmuir Probe, PLP, is an attractive geometry because the ram ion current is very constant over many Volts of a sweep, allowing the ion density and electron temperature to be determined independently with the same instrument, at different points on the sweep. However, when the physical voltage reference is itself small and electrically floating as with a small spacecraft, the spacecraft and probe system become a double probe where the current collection theory depends on the interaction of the spacecraft with the plasma which is generally not as simple as the probe itself. The Sheath-less PLP, SPLP, interlaces on a single ram facing surface, two variably biased probe elements, broke