Recent advances and developments on integrating nanotechnology with chemiluminescence assays.

PubMed

Tiwari, Ashish; Dhoble, S J

2018-04-01

Chemiluminescence (CL) techniques are extensively utilized for detection of analytes due to their high sensitivity, rapidity and selectivity. With the advent of nanotechnology and incorporation of the nanoparticles in the CL system has revolutionized the assays due to their unique optical and mechanical properties. Several CL-based reactions have been developed where these nanoparticle based CL sensors have evolved as excellent prospects for sensing in various analytical applications. This review article addresses the nanoparticles based CL detection system that are recently developed, the mechanisms has been summarized and the role of luminophors have been discussed. This article critically analyzes the optimal conditions for the CL detection along with quantitative assessment of the analytes. We have included the use of semiconductor nanoparticles, metal nanoparticles, graphene based nanostructures, mesoporous nanospheres, layered double hydroxides, clays for CL detection. The scope and application of these nanoscale material based CL system in various branches of science and technology including chemistry, biomedical applications, pharmaceutics, food, environmental and toxicological applications has been critically summarized. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluid shear stress enhances the cell volume decrease of osteoblast cells by increasing the expression of the ClC-3 chloride channel

PubMed Central

LIU, LI; CAI, SIYI; QIU, GUIXING; LIN, JIN

2016-01-01

ClC-3 is a volume-sensitive chloride channel that is responsible for cell volume adjustment and regulatory cell volume decrease (RVD). In order to evaluate the effects of fluid shear stress (FSS) stimulation on the osteoblast ClC-3 chloride channel, MC3T3-E1 cells were stimulated by FSS in the experimental group. Fluorescence quantitative polymerase chain reaction was used to detect changes in ClC-3 mRNA expression, the chloride ion fluorescent probe N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (MQAE) was used to detect the chloride channel activity, and whole-cell patch clamping was used to monitor the changes in the volume-sensitive chloride current activated by a hypotonic environment following mechanical stimulation. The results show that the expression of the osteoblast chloride channel ClC-3 was significantly higher in the FSS group compared with the control group. MQAE fluorescence intensity was significantly reduced in the FSS group compared to the control group, suggesting that mechanical stimulation increased chloride channel activity and increased the efflux of intracellular chloride ions. Image analysis of osteoblast volume changes showed that osteoblast RVD was enhanced by mechanical stimulation. Whole-cell patch clamping showed that the osteoblast volume-sensitive chloride current was larger in the stimulated group compared to the control group, suggesting that elevated ClC-3 chloride channel expression results in an increased volume-sensitive chloride current. In conclusion, FSS stimulation enhances the RVD of osteoblast cell by increasing the expression of the ClC-3 and enhancing the chloride channel activity. PMID:27073622

Gold nanoclusters-based chemiluminescence resonance energy transfer method for sensitive and label-free detection of trypsin.

PubMed

You, Xiaoying; Li, Yinhuan; Li, Baoping; Ma, Jie

2016-01-15

A chemiluminescence resonance energy transfer (CRET) platform was developed for sensitive and label-free detection of protease by using trypsin as a model analyte. In this CRET platform, bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide chemiluminescence (CL) reaction was utilized as an energy donor and bovine serum albumin (BSA)-stabilized gold nanoclusters (Au NCs) as an energy acceptor. The BSA-stabilized Au NCs triggered the CRET phenomenon by accepting the energy from TCPO-H2O2 CL reaction, thus producing intense CL. In the presence of trypsin, the protein template of BSA-stabilized Au NCs was digested, which frustrated the energy transfer efficiency between the CL donor and the BSA-stabilized Au NCs, leading to a significant decrease in the CL signal. The decreased CL signal was proportional to the logarithm of trypsin concentration in the range of 0.01-50.0µg mL(-1). The detection limit for trypsin was 9ng mL(-)(1) and the relative standard deviations were lesser than 3% (n=11). This Au NCs-based CRET platform was successfully applied to the determination of trypsin in human urine samples, demonstrating its potential application in clinical diagnosis. Copyright © 2015 Elsevier B.V. All rights reserved.

Sensitive and selective determination of fluvoxamine maleate using a sensitive chemiluminescence system based on the alkaline permanganate-Rhodamine B-gold nanoparticles reaction.

PubMed

Hassanzadeh, Javad; Amjadi, Mohammad

2015-06-01

A high-yield chemiluminescence (CL) system based on the alkaline permanganate-Rhodamine B reaction was developed for the sensitive determination of fluvoxamine maleate (Flu). Rhodamine B is oxidized by alkaline KMnO4 and a weak CL emission is produced. It was demonstrated that gold nanoparticles greatly enhance this CL emission due to their interaction with Rhodamine B molecules. It is also observed that sodium dodecyl sulfate, an anionic surfactant, can strongly increase this enhancement. In addition, it was demonstrated that a notable decrease in the CL intensity is observed in the presence of Flu. This may be related to Flu oxidation with KMnO4 . There is a linear relationship between the decrease in CL intensity and the Flu concentration over a range of 2-300 µg/L. A new simple, rapid and sensitive CL method was developed for the determination of Flu with a detection limit (3s) of 1.35 µg/L. The proposed method was used for the determination of Flu in pharmaceutical and urine samples. Copyright © 2014 John Wiley & Sons, Ltd.

Real time imaging of live cell ATP leaking or release events by chemiluminescence microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yun

The purpose of this research was to expand the chemiluminescence microscopy applications in live bacterial/mammalian cell imaging and to improve the detection sensitivity for ATP leaking or release events. We first demonstrated that chemiluminescence (CL) imaging can be used to interrogate single bacterial cells. While using a luminometer allows detecting ATP from cell lysate extracted from at least 10 bacterial cells, all previous cell CL detection never reached this sensitivity of single bacteria level. We approached this goal with a different strategy from before: instead of breaking bacterial cell membrane and trying to capture the transiently diluted ATP with themore » firefly luciferase CL assay, we introduced the firefly luciferase enzyme into bacteria using the modern genetic techniques and placed the CL reaction substrate D-luciferin outside the cells. By damaging the cell membrane with various antibacterial drugs including antibiotics such as Penicillins and bacteriophages, the D-luciferin molecules diffused inside the cell and initiated the reaction that produces CL light. As firefly luciferases are large protein molecules which are retained within the cells before the total rupture and intracellular ATP concentration is high at the millmolar level, the CL reaction of firefly luciferase, ATP and D-luciferin can be kept for a relatively long time within the cells acting as a reaction container to generate enough photons for detection by the extremely sensitive intensified charge coupled device (ICCD) camera. The result was inspiring as various single bacterium lysis and leakage events were monitored with 10-s temporal resolution movies. We also found a new way of enhancing diffusion D-luciferin into cells by dehydrating the bacteria. Then we started with this novel single bacterial CL imaging technique, and applied it for quantifying gene expression levels from individual bacterial cells. Previous published result in single cell gene expression quantification mainly used a fluorescence method; CL detection is limited because of the difficulty to introduce enough D-luciferin molecules. Since dehydration could easily cause proper size holes in bacterial cell membranes and facilitate D-luciferin diffusion, we used this method and recorded CL from individual cells each hour after induction. The CL light intensity from each individual cell was integrated and gene expression levels of two strain types were compared. Based on our calculation, the overall sensitivity of our system is already approaching the single enzyme level. The median enzyme number inside a single bacterium from the higher expression strain after 2 hours induction was quantified to be about 550 molecules. Finally we imaged ATP release from astrocyte cells. Upon mechanical stimulation, astrocyte cells respond by increasing intracellular Ca 2+ level and releasing ATP to extracellular spaces as signaling molecules. The ATP release imaged by direct CL imaging using free firefly luciferase and D-luciferin outside cells reflects the transient release as well as rapid ATP diffusion. Therefore ATP release detection at the cell surface is critical to study the ATP release mechanism and signaling propagation pathway. We realized this cell surface localized ATP release imaging detection by immobilizing firefly luciferase to streptavidin beads that attached to the cell surface via streptavidin-biotin interactions. Both intracellular Ca 2+ propagation wave and extracellular ATP propagation wave at the cell surface were recorded with fluorescence and CL respectively. The results imply that at close distances from the stimulation center (<120 μm) extracellular ATP pathway is faster, while at long distances (>120 μm) intracellular Ca 2+ signaling through gap junctions seems more effective.« less

Self-Catalyzing Chemiluminescence of Luminol-Diazonium Ion and Its Application for Catalyst-Free Hydrogen Peroxide Detection and Rat Arthritis Imaging.

PubMed

Zhao, Chunxin; Cui, Hongbo; Duan, Jing; Zhang, Shenghai; Lv, Jiagen

2018-02-06

We report the unique self-catalyzing chemiluminescence (CL) of luminol-diazonium ion (N 2 + -luminol) and its analytical potential. Visual CL emission was initially observed when N 2 + -luminol was subjected to alkaline aqueous H 2 O 2 without the aid of any catalysts. Further experimental investigations found peroxidase-like activity of N 2 + -luminol on the cleavage of H 2 O 2 into OH • radical. Together with other experimental evidence, the CL mechanism is suggested as the activation of N 2 + -luminol and its dediazotization product 3-hydroxyl luminol by OH • radical into corresponding intermediate radicals, and then further oxidation to excited-state 3-N 2 + -phthalic acid and 3-hydroxyphthalic acid, which finally produce 415 nm CL. The self-catalyzing CL of N 2 + -luminol provides us an opportunity to achieve the attractive catalyst-free CL detection of H 2 O 2 . Experiments demonstrated the 10 -8 M level detection sensitivity to H 2 O 2 as well as to glucose or uric acid if presubjected to glucose oxidase or uricase. With the exampled determination of serum glucose and uric acid, N 2 + -luminol shows its analytical potential for other analytes linking the production or consumption of H 2 O 2 . Under physiological condition, N 2 + -luminol exhibits highly selective and sensitive CL toward 1 O 2 among the common reactive oxygen species. This capacity supports the significant application of N 2 + -luminol for detecting 1 O 2 in live animals. By imaging the arthritis in LEW rats, N 2 + -luminol CL is demonstrated as a potential tool for mapping the inflammation-relevant biological events in a live body.

Sensitive detection of chlorine in iron oxide by single pulse and dual pulse laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Pedarnig, J. D.; Haslinger, M. J.; Bodea, M. A.; Huber, N.; Wolfmeir, H.; Heitz, J.

2014-11-01

The halogen chlorine is hard to detect in laser-induced breakdown spectroscopy (LIBS) mainly due to its high excited state energies of 9.2 and 10.4 eV for the most intense emission lines at 134.72 nm and 837.59 nm, respectively. We report on sensitive detection of Cl in industrial iron oxide Fe2O3 powder by single-pulse (SP) and dual-pulse (DP) LIBS measurements in the near infrared range in air. In compacted powder measured by SP excitation (Nd:YAG laser, 532 nm) Cl was detected with limit of detection LOD = 440 ppm and limit of quantitation LOQ = 720 ppm. Orthogonal DP LIBS was studied on pressed Fe2O3 pellets and Fe3O4 ceramics. The transmission of laser-induced plasma for orthogonal Nd:YAG 1064 nm and ArF 193 nm laser pulses showed a significant dependence on interpulse delay time (ipd) and laser wavelength (λL). The UV pulses (λL = 193 nm) were moderately absorbed in the plasma and the Cl I emission line intensity was enhanced while IR pulses (λL = 1064 nm) were not absorbed and Cl signals were not enhanced at ipd = 3 μs. The UV laser enhancement of Cl signals is attributed to the much higher signal/background ratio for orthogonal DP excitation compared to SP excitation and to the increased plasma temperature and electron number density. This enabled measurement at a very short delay time of td ≥ 0.1 μs with respect to the re-excitation pulse and detection of the very rapidly decaying Cl emission with higher efficiency.

Determination of phenformin hydrochloride using molecular imprinting technology coupled with flow-injection chemiluminescence.

PubMed

Liu, Zhenbo; Jia, Fengyan; Wang, Wenwen; Wang, Cuixia; Liu, Yongming

2012-01-01

A novel method was developed using molecular imprinting technology (MIT) coupled with flow-injection chemiluminescence (FI-CL) for highly sensitive detection of phenformin hydrochloride (PH). The phenformin imprinted polymer was synthesized with methacrylic acid (MAA) as a functional monomer and ethylene glycol dimethacrylate (EGDMA) as a cross-linker. Newly synthesized molecularly imprinted polymer (MIP) particles were packed into a column as a selective recognition element for determination of PH. A CL method for the determination of PH was developed based on the CL reaction of PH with N-bromosuccinimide sensitized by eosin Y in basic media. The optimization of detection conditions was investigated. The CL intensity responded linearly to the concentration of PH in the range 0.09-2.0 µg/mL, with a correlation coefficient of 0.9920. The detection limit was 0.031 µg/mL. The relative standard deviation for the determination of 1.0 µg/mL PH solution was 1.0% (n = 11). The method was applied to the determination of PH in urine samples, with satisfactory results. Copyright © 2011 John Wiley & Sons, Ltd.

High-sensitivity imaging method of singlet oxygen and superoxide anion in photodynamic and sonodynamic actions

NASA Astrophysics Data System (ADS)

Xing, Da; He, Yonghong; Hao, Min; Chen, Qun

2004-07-01

A novel method of photodynamic diagnosis (PDD) of cancer mediated by chemiluminescence (CL) probe is presented. The mechanism for photodynamic therapy (PDT) involves reactive oxygen species (ROS), such as singlet oxygen (1O2) and superoxide (O2-), generated by during the photochemical process. Both 1O2 and O2- can react with Cypridina luciferin analogue (FCLA), a highly selective CL probe for detecting the ROS. Chemiluminescence from the reaction of FCLA with the ROS, at about 530 nm, was detected by a highly sensitive ICCD system. The CL was markedly inhibited by the addition of 10 mmol/L sodium azide (NaN3) in a sample solution. Similar phenomena, with lesser extents of changes, were observed at the additions of 10 μmol/L superoxide dismutase (SOD), 10 mmol/L mannitol, and 100 μg/mL catalase, respectively. This indicates that the detected CL signals were mainly from ROS generated during the photosensitization reactions. Also, the chemiluminescence method was used to detect the ROS during sonodynamic action, both in vitro and in vivo. ROS formation during sonosensitizations of HpD and ATX-70 were detected using our newly-developed imaging technique, in real time, on tumor bearing animals. This method can provide a new means in clinics for tumor diagnosis.

Selenium-binding protein 1: a sensitive urinary biomarker to detect heavy metal-induced nephrotoxicity.

PubMed

Lee, Eui Kyung; Shin, Young-Jun; Park, Eun Young; Kim, Nam Deuk; Moon, Aree; Kwack, Seung Jun; Son, Ji Yeon; Kacew, Sam; Lee, Byung Mu; Bae, Ok-Nam; Kim, Hyung Sik

2017-04-01

Identifying novel biomarkers to detect nephrotoxicity is clinically important. Here, we attempted to identify new biomarkers for mercury-induced nephrotoxicity and compared their sensitivity to that of traditional biomarkers in animal models. Comparative proteomics analysis was performed in kidney tissues of Sprague-Dawley rats after oral treatment with HgCl 2 (0.1, 1, or 5 mg/kg/day) for 21 days. Kidney cortex tissues were analyzed by two-dimensional gel electrophoresis/matrix-assisted laser desorption/ionization, and differentially expressed proteins were identified. The corresponding spots were quantitated by RT-PCR. Selenium-binding protein 1 (SBP1) was found to be the most markedly upregulated protein in the kidney cortex of rats after HgCl 2 administration. However, blood urea nitrogen, serum creatinine, and glucose levels increased significantly only in the 1 or 5 mg/kg HgCl 2 -treated groups. A number of urinary excretion proteins, including kidney injury molecule-1, clusterin, monocyte chemoattractant protein-1, and β-microglobulin, increased dose-dependently. Histopathological examination revealed severe proximal tubular damage in high-dose (5 mg/kg) HgCl 2 -exposed groups. In addition, urinary excretion of SBP1 significantly increased in a dose-dependent manner. To confirm the critical role of SBP1 as a biomarker for nephrotoxicity, normal kidney proximal tubular cells were treated with HgCl 2 , CdCl 2 , or cisplatin for 24 h. SBP1 levels significantly increased in conditioned media exposed to nephrotoxicants, but decreased in cell lysates. Our investigations suggest that SBP1 may play a critical role in the pathological processes underlying chemical-induced nephrotoxicity. Thus, urinary excretion of SBP1 might be a sensitive and specific biomarker to detect early stages of kidney injury.

N-bromosuccinimide-fluorescein based sensitive flow-injection chemiluminescence determination of phenformin.

PubMed

Wang, Zhouping; Zhang, Zhujun; Fu, Zhifeng; Fang, Luqiu; Zhang, Xiao

2004-02-01

A novel and highly sensitive method for the determination of phenformin over the range of 6 x 10(-9) - 1 x 10(-5) g ml(-1) in pharmaceutical formulations with flow-injection chemiluminescence (CL) detection is proposed. The method is based on the CL produced during the oxidation of N-bromosuccinimide (NBS) in an alkaline medium in the presence of fluorescein as an effective energy transfer agent. The use of cetyltrimethylammonium bromide (CTAB) as a sensitizer enhances the signal magnitude by about 100 times. The detection limit is 2 x 10(-9) g ml(-1) (3sigma) with a relative standard deviation of 2.3% (n = 11) at 1 x 10(-7) g ml(-1) phenformin. Ninety samples can be determined per hour. The method was evaluated by carrying out a recovery study and by the analysis of commercial formulations. The obtained results compared well with those by an official method, and demonstrated good accuracy and precision. The possible CL mechanism of the proposed system was also briefly analyzed.

A cascade amplification strategy based on rolling circle amplification and hydroxylamine amplified gold nanoparticles enables chemiluminescence detection of adenosine triphosphate.

PubMed

Wang, Ping; Zhang, Tonghuan; Yang, Taoyi; Jin, Nan; Zhao, Yanjun; Fan, Aiping

2014-08-07

A highly sensitive and selective chemiluminescent (CL) biosensor for adenosine triphosphate (ATP) was developed by taking advantage of the ATP-dependent enzymatic reaction (ATP-DER), the powerful signal amplification capability of rolling circle amplification (RCA), and hydroxylamine-amplified gold nanoparticles (Au NPs). The strategy relies on the ability of ATP, a cofactor of T4 DNA ligase, to trigger the ligation-RCA reaction. In the presence of ATP, the T4 DNA ligase catalyzes the ligation reaction between the two ends of the padlock probe, producing a closed circular DNA template that initiates the RCA reaction with phi29 DNA polymerase and dNTP. Therein, many complementary copies of the circular template can be generated. The ATP-DER is eventually converted into a detectable CL signal after a series of processes, including gold probe hybridization, hydroxylamine amplification, and oxidative gold metal dissolution coupled with a simple and sensitive luminol CL reaction. The CL signal is directly proportional to the ATP level. The results showed that the detection limit of the assay is 100 pM of ATP, which compares favorably with those of other ATP detection techniques. In addition, by taking advantage of ATP-DER, the proposed CL sensing system exhibits extraordinary specificity towards ATP and could distinguish the target molecule ATP from its analogues. The proposed method provides a new and versatile platform for the design of novel DNA ligation reaction-based CL sensing systems for other cofactors. This novel ATP-DER based CL sensing system may find wide applications in clinical diagnosis as well as in environmental and biomedical fields.

A novel array of chemiluminescence sensors for sensitive, rapid and high-throughput detection of explosive triacetone triperoxide at the scene.

PubMed

Li, Xiaohua; Zhang, Zhujun; Tao, Liang

2013-09-15

Triacetone triperoxide (TATP) is relatively easy to make and has been used in various terrorist acts. Early but easy detection of TATP is highly desired. We designed a new type sensor array for H2O2. The unique CL sensor array was based on CeO2 nanoparticles' membranes, which have an excellent catalytic effect on the luminol-H2O2 CL reaction in alkaline medium. It exhibits a linear range for the detection of H2O2 from 1.0×10(-8) to 5.0×10(-5)M (R(2)=0.9991) with a 1s response time. The detection limit is 1.0×10(-9)M. Notably, the present approach allows the design of CL sensor array assays in a more simple, time-saving, long-lifetime, high-throughput, and economical approach when compared with conventional CL sensor. It is conceptually different from conventional CL sensor assays. The novel sensor array has been successfully applied for the detection of TATP at the scene. Copyright © 2013 Elsevier B.V. All rights reserved.

Polystyrene Oxygen Optodes Doped with Ir(III) and Pd(II) meso-Tetrakis(pentafluorophenyl)porphyrin Using an LED-Based High-Sensitivity Phosphorimeter.

PubMed

Filho, Alexandre F De Moraes; Gewehr, Pedro M; Maia, Joaquim M; Jakubiak, Douglas R

2018-06-15

This paper presents a gaseous oxygen detection system based on time-resolved phosphorimetry (time-domain), which is used to investigate O2 optical transducers. The primary sensing elements were formed by incorporating iridium(III) and palladium(II) meso -tetrakis(pentafluorophenyl)porphyrin complexes (IrTFPP-CO-Cl and PdTFPP) in polystyrene (PS) solid matrices. Probe excitation was obtained using a violet light-emitting diode (LED) (low power), and the resulting phosphorescence was detected by a high-sensitivity compact photomultiplier tube. The detection system performance and the preparation of the transducers are presented along with their optical properties, phosphorescence lifetimes, calibration curves and photostability. The developed lifetime measuring system showed a good signal-to-noise ratio, and reliable results were obtained from the optodes, even when exposed to moderate levels of O2. The new IrTFPP-CO-Cl membranes exhibited room temperature phosphorescence and moderate sensitivity: <τ0>/<τ21%> ratio of ≈6. A typically high degree of dynamic phosphorescence quenching was observed for the traditional indicator PdTFPP: <τ0>/<τ21%> ratio of ≈36. Pulsed-source time-resolved phosphorimetry combined with a high-sensitivity photodetector can offer potential advantages such as: (i) major dynamic range, (ii) extended temporal resolution (Δτ/Δ[O2]) and (iii) high operational stability. IrTFPP-CO-Cl immobilized in polystyrene is a promising alternative for O2 detection, offering adequate photostability and potentially mid-range sensitivity over Pt(II) and Pd(II) metalloporphyrins.

Chemiluminescent labels released from long spacer arm-functionalized magnetic particles: a novel strategy for ultrasensitive and highly selective detection of pathogen infections.

PubMed

Yang, Haowen; Liang, Wenbiao; He, Nongyue; Deng, Yan; Li, Zhiyang

2015-01-14

Previously, the unique advantages provided by chemiluminescence (CL) and magnetic particles (MPs) have resulted in the development of many useful nucleic acid detection methods. CL is highly sensitive, but when applied to MPs, its intensity is limited by the inner filter-like effect arising from excess dark MPs. Herein, we describe a modified strategy whereby CL labels are released from MPs to eliminate this negative effect. This approach relies on (1) the magnetic capture of target molecules on long spacer arm-functionalized magnetic particles (LSA-MPs), (2) the conjugation of streptavidin-alkaline phosphatase (SA-AP) to biotinylated amplicons of target pathogens, (3) the release of CL labels (specifically, AP tags), and (4) the detection of the released labels. CL labels were released from LSA-MPs through LSA ultrasonication or DNA enzymolysis, which proved to be the superior method. In contrast to conventional MPs, LSA-MPs exhibited significantly improved CL detection, because of the introduction of LSA, which was made of water-soluble carboxymethylated β-1,3-glucan. Detection of hepatitis B virus with this technique revealed a low detection limit of 50 fM, high selectivity, and excellent reproducibility. Thus, this approach may hold great potential for early stage clinical diagnosis of infectious diseases.

The chemiluminescent response of human monocytes to red cells sensitized with monoclonal anti-Rh(D) antibodies.

PubMed

Hadley, A G; Kumpel, B M; Merry, A H

1988-01-01

Luminol-enhanced chemiluminescence (CL) was used to assess the metabolic response of human monocytes to red cells sensitized with known amounts of anti-Rh(D). Monoclonal antibodies were used to facilitate a comparison between the functional activities of IgG1 and IgG3 subclasses. The detection of CL provided a simple, rapid and semi-quantitative means of measuring monocyte response to sensitized red cells (IgG-RBC). Monocyte response to IgG3-RBC was quantitatively greater, more rapid and less susceptible to inhibition by fluid phase IgG than monocyte response to IgG1-RBC. The minimum levels of sensitization required to elicit CL from monocytes were approximately 2500 IgG3 molecules per red cell, or approximately 5000 IgG1 molecules per cell.

Ultra-sensitive chemiluminescence imaging DNA hybridization method in the detection of mosquito-borne viruses and parasites.

PubMed

Zhang, Yingjie; Liu, Qiqi; Zhou, Biao; Wang, Xiaobo; Chen, Suhong; Wang, Shengqi

2017-01-25

Mosquito-borne viruses (MBVs) and parasites (MBPs) are transmitted through hematophagous arthropods-mosquitoes to homoiothermous vertebrates. This study aims at developing a detection method to monitor the spread of mosquito-borne diseases to new areas and diagnose the infections caused by MBVs and MBPs. In this assay, an ultra-sensitive chemiluminescence (CL) detection method was developed and used to simultaneously detect 19 common MBVs and MBPs. In vitro transcript RNA, virus-like particles (VLPs), and plasmids were established as positive or limit of detection (LOD) reference materials. MBVs and MBPs could be genotyped with high sensitivity and specificity. The cut-off values of probes were calculated. The absolute LODs of this strategy to detect serially diluted in vitro transcribed RNAs of MBVs and serially diluted plasmids of MBPs were 10 2 -10 3 copies/μl and 10 1 -10 2 copies/μl, respectively. Further, the LOD of detecting a strain of pre-quantified JEV was 10 1.8 -10 0.8 PFU/ml, fitted well in a linear regression model (coefficient of determination = 0.9678). Ultra-sensitive CL imaging DNA hybridization was developed and could simultaneously detect various MBVs and MBPs. The method described here has the potential to provide considerable labor savings due to its ability to screen for 19 mosquito-borne pathogens simultaneously.

Ultrasensitive determination of DNA sequences by flow injection chemiluminescence using silver ions as labels.

PubMed

Zheng, Lichun; Liu, Xiuhui; Zhou, Min; Ma, Yongjun; Wu, Guofan; Lu, Xiaoquan

2014-10-27

We presented a new strategy for ultrasensitive detection of DNA sequences based on the novel detection probe which was labeled with Ag(+) using metallothionein (MT) as a bridge. The assay relied on a sandwich-type DNA hybridization in which the DNA targets were first hybridized to the captured oligonucleotide probes immobilized on Fe3O4@Au composite magnetic nanoparticles (MNPs), and then the Ag(+)-modified detection probes were used to monitor the presence of the specific DNA targets. After being anchored on the hybrids, Ag(+) was released down through acidic treatment and sensitively determined by a coupling flow injection-chemiluminescent reaction system (Ag(+)-Mn(2+)-K2S2O8-H3PO4-luminol) (FI-CL). The experiment results showed that the CL intensities increased linearly with the concentrations of DNA targets in the range from 10 to 500 pmol L(-1) with a detection limit of 3.3 pmol L(-1). The high sensitivity in this work may be ascribed to the high molar ratio of Ag(+)-MT, the sensitive determination of Ag(+) by the coupling FI-CL reaction system and the perfect magnetic separation based on Fe3O4@Au composite MNPs. Moreover, the proposed strategy exhibited excellent selectivity against the mismatched DNA sequences and could be applied to real samples analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

Error Detection and Correction in Spelling.

ERIC Educational Resources Information Center

Lydiatt, Steve

1984-01-01

Teachers can discover students' means of dealing with spelling as a problem through investigations of their error detection and correction skills. Approaches for measuring sensitivity and bias are described, as are means of developing appropriate instructional activities. (CL)

Morphologically manipulated Ag/ZnO nanostructures as surface enhanced Raman scattering probes for explosives detection

NASA Astrophysics Data System (ADS)

Shaik, Ummar Pasha; Hamad, Syed; Ahamad Mohiddon, Md.; Soma, Venugopal Rao; Ghanashyam Krishna, M.

2016-03-01

The detection of secondary explosive molecules (e.g., ANTA, FOX-7, and CL-20) using Ag decorated ZnO nanostructures as surface enhanced Raman scattering (SERS) probes is demonstrated. ZnO nanostructures were grown on borosilicate glass substrates by rapid thermal oxidation of metallic Zn films at 500 °C. The oxide nanostructures, including nanosheets and nanowires, emerged over the surface of the Zn film leaving behind the metal residue. We demonstrate that SERS measurements with concentrations as low as 10 μM, of the three explosive molecules ANTA, FOX-7, and CL-20 over ZnO/Ag nanostructures, resulted in enhancement factors of ˜107, ˜107, and ˜104, respectively. These measurements validate the high sensitivity of detection of explosive molecules using Ag decorated ZnO nanostructures as SERS substrates. The Zn metal residue and conditions of annealing play an important role in determining the detection sensitivity.

N-Hydroxysuccinimide as an effective chemiluminescence coreactant for highly selective and sensitive detection.

PubMed

Saqib, Muhammad; Li, Suping; Gao, Wenyue; Majeed, Saadat; Qi, Liming; Liu, Zhongyuan; Xu, Guobao

2016-12-01

The development of novel coreactants for chemiluminescence is very important to improve performance and widen its applications without using any other catalyst. N-Hydroxysuccinimide (NHS), a highly popular amine-reactive, activating, or protecting reagent in biochemical applications and organic synthesis, has been explored as an efficient and stable chemiluminescence coreactant for the first time. The chemiluminescence intensity of the newly developed luminol-NHS system is about 22 times higher than that of the traditional luminol-H 2 O 2 system. Chemiluminescence of this system is dramatically enhanced by Co 2+ . This new chemiluminescence system is then applied for the highly selective and ultrasensitive detection of Co 2+ with limit of detection (0.01 nM) better than those of several conventional analytical methods. This system also enables the efficient detection of luminol (LOD = 7 pM) and NHS (LOD = 3.0 μM) with excellent sensitivity. This chemiluminescence method was then also utilized to detect Co 2+ in tap water and blue silica gel with excellent recoveries in the range 99.20-103.07 %. This novel chemiluminescence system has several advantages, including simple, cost-effective, highly sensitive, selective, and wide linear range. We expect that this chemiluminescence system will be a promising candidate for chemical and biological sensing. Graphical Abstract Comparison of CL peak intensities of classical luminol-H 2 O 2 CL system and newly developed luminol-NHS CL system.

Simple and rapid chemiluminescence aptasensor for Hg2+ in contaminated samples: A new signal amplification mechanism.

PubMed

Qi, Yingying; Xiu, Fu-Rong; Yu, Gending; Huang, Lili; Li, Baoxin

2017-01-15

Detection of ultralow concentration of heavy metal ion Hg 2+ is important for human health protection and environment monitoring because of the gradual accumulation in environmental and biological fields. Herein, we report a convenient chemiluminescence (CL) biosensing platform for ultrasensitive Hg 2+ detection by signal amplification mechanism from positively charged gold nanoparticles ((+)AuNPs). It is based on (+)AuNPs charge effect and aptamer conformation change induced by target to stimulate the generation of CL in the presence of H 2 O 2 and luminol without high salt medium. Notably particularly, the typical problem of the high salt medium from (-) AuNPs system, like influencing aptamers' bind with target and hindering CL reaction can be effectively addressed through the direct introduction of (+)AuNPs. Therefore, the proposed biosensing exhibits a high sensitivity toward target Hg 2+ with a detection limit of 16 pM, which is far below the limit (10nM) defined by the U.S. Environmental Protection Agency in drinkable water, and is about 10-fold lower than the previously reported aptamer-based assays for Hg 2+ . This sensing platform provides a simple, rapid, and cost-effective approach for label-free sensitive detection of Hg 2+ . Moreover, it is universal for the detection of other targets. Undoubtedly, such a direct utilizing of (+)AuNPs' charge effect will provide a new signal amplification way for label-free aptamer-based CL analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

A dual-emission and large Stokes shift fluorescence probe for real-time discrimination of ROS/RNS and imaging in live cells.

PubMed

Guo, Ting; Cui, Lei; Shen, Jiaoning; Wang, Rui; Zhu, Weiping; Xu, Yufang; Qian, Xuhong

2013-03-04

A novel dual-emission fluorescence probe has been developed for specific and sensitive detection of hypochlorite (ClO(-)). Upon addition of ClO(-), significant changes in fluorescence emission intensity at two discrete wavelengths were observed. Meanwhile OONO(-) led to only a single-channel fluorescence enhancement. This feature makes it a clear advantage in distinguishing ClO(-), RNS from other ROS.

A rare 3D chloro-laced Mn(II) metal-organic framework to show sensitive probing effect to Hg2+

NASA Astrophysics Data System (ADS)

Ming, Mei; Bai, Na

2017-10-01

Two 3D Mn(II) metal-organic frameworks (MOFs), [Mn(L-Cl)(DMA)](H2O) (1) and Mn(L-CH3)(DMA) (2) (H2L-Cl = 2,2'-dichloro-4,4'-azodibenzoic acid, H2L-CH3 = 2,2'-dimethyl-4,4'-azodibenzoic acid) were synthesized under similar solvothermal condition. Both MOFs crystallize in the orthorhombic system and show the 3D rod-packing networks in 2-fold interpenetrated pattern with sra topology. Due to the different substituent laces of MOFs (-Cl vs -CH3), only MOF 1 shows highly selective and sensitive fluorescence sensing effect for detecting Hg2+ ion.

Testing a High-Sensitivity ATR FTIR Water Monitor for Ionic CWA Breakdown Products

DTIC Science & Technology

2003-12-31

for ClO4− (perchlorate) 37 The Limits of Detection for ClO3− (chlorate) 41 The Limits of Detection for PFOS− ( perfluorooctanesulfonate ) 44 The... perfluorooctanesulfonate (PFOS−), C8F17SO3−, perfluorobutanesulfonate (PFBS−), C4F9SO3−, trifluoromethanesulfonate, CF3SO3−, permanganate, MnO4−, perrhenate, ReO4...become a significant environmental concern in many western states.3 Perfluorooctanesulfonate was, for decades a key ingredient in aqueous film

Quenching the chemiluminescence of acridinium ester by graphene oxide for label-free and homogeneous DNA detection.

PubMed

He, Yi; Huang, Guangming; Cui, Hua

2013-11-13

It was found that graphene oxide (GO) could effectively quench the chemiluminescence (CL) emission from a acridinium ester (AE)-hydrogen peroxide system. By taking advantage of this quenching effect, as a proof of concept, a label-free and homogeneous DNA assay was developed for the detection of Mycobacterium tuberculosis DNA. In the absence of target DNA, both probe DNA and AE were absorbed on the surface of GO, producing a weak CL emission owing to the CL quenching effect of GO. However, in the presence of target DNA, a double-stranded structure of DNA was generated, leading to the release of the oligonucleotide from the GO surface. AE favors binding with double-stranded DNA, which will be released from the GO surface; thus, the quenching effect of GO will be no longer effective and a strong CL signal can be observed. This assay can detect M. tuberculosis DNA with a detection limit of 0.65 nM. This sensitivity is lower than that of previously reported electrochemical detection.

Development of carbon dots modified fluorescent molecular imprinted Polymer@Ag/AgCl nanoparticle for hepatocellular carcinoma marker

NASA Astrophysics Data System (ADS)

Karfa, Paramita; Madhuri, Rashmi; Sharma, Prashant K.

2017-05-01

In this work, a sensitive and selective fluorescent molecularly imprinted polymer (MIP) was developed for detection of hepatocellular carcinoma (HCC) biomarker i.e. alpha feto protein (AFP) using Ag/AgCl as platform. Here, the carbon dots and Ag/AgCl nanoparticles were functionalized with vinyl groups and used as functional monomer for synthesis of AFP-imprinted polymer. The imprinted polymer shows a linear range of 3.96 ng mL-1 to 80.0 ng mL-1 with detection limit of 0.42 ng mL-1.The adsorption property of the MIP@Ag/AgCl was studied and shows the high affinity binding towards their target analyte without any cross-reactivity and false-positive or false-negative results.

Mass Spectrometry Identification of N-Chlorinated Dipeptides in Drinking Water.

PubMed

Huang, Guang; Jiang, Ping; Li, Xing-Fang

2017-04-04

We report the identification of N-chlorinated dipeptides as chlorination products in drinking water using complementary high-resolution quadrupole time-of-flight (QTOF) and quadrupole ion-trap mass spectrometry techniques. First, three model dipeptides, tyrosylglycine (Tyr-Gly), tyrosylalanine (Tyr-Ala), and phenylalanylglycine (Phe-Gly), reacted with sodium hypochlorite, and these reaction solutions were analyzed by QTOF. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N,N-di-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala were identified as the major products based on accurate masses, 35 Cl/ 37 Cl isotopic patterns, and MS/MS spectra. These identified N-chlorinated dipeptides were synthesized and found to be stable in water over 10 days except N,N-di-Cl-Phe-Gly. To enable sensitive detection of N-chlorinated dipeptides in authentic water, we developed a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method with multiple reaction monitoring (MRM) mode. N-Cl-Tyr-Gly, N,N-di-Cl-Tyr-Gly, N-Cl-Phe-Gly, N-Cl-Tyr-Ala, and N,N-di-Cl-Tyr-Ala along with their corresponding dipeptides were detected in authentic tap water samples. The dipeptides were clearly detected in the raw water, but the N-chlorinated dipeptides were at background levels. These results suggest that the N-chlorinated dipeptides are produced by chlorination. This study has identified N-chlorinated dipeptides as new disinfection byproducts in drinking water. The strategy developed in this study can be used to identify chlorination products of other peptides in drinking water.

Flow-injection system for automated dissolution testing of isoniazid tablets with chemiluminescence detection.

PubMed

Li, B; Zhang, Z; Liu, W

2001-05-30

A simple and sensitive flow-injection chemiluminescence (CL) system for automated dissolution testing is described and evaluated for monitoring of dissolution profiles of isoniazid tablets. The undissolved suspended particles in the dissolved solution were eliminated via on-line filter. The novel CL system of KIO(4)-isoniazid was also investigated. The sampling frequency of the system was 120 h(-1). The dissolution profiles of isoniazid fast-release tablets from three sources were determined, which demonstrates the stability, great sensitivity, large dynamic measuring range and robustness of the system.

Capillary electrophoresis-chemiluminescence detection for carcino-embryonic antigen based on aptamer/graphene oxide structure.

PubMed

Zhou, Zi-Ming; Feng, Zhe; Zhou, Jun; Fang, Bi-Yun; Qi, Xiao-Xiao; Ma, Zhi-Ya; Liu, Bo; Zhao, Yuan-Di; Hu, Xue-Bin

2015-02-15

A new strategy is proposed for determination of carcino-embryonic antigen (CEA) based on aptamer/graphene oxide (Apt/GO) by capillary electrophoresis-chemiluminescence (CE-CL) detection system. CEA aptamer conjugated with horseradish peroxidase (HRP) firstly mixes with GO, and the CL will be quenched because the stack of HRP-Apt on GO leads to chemiluminescence resonance energy transfer (CRET). When CEA exists, the specific combination of HRP-Apt and CEA can form HRP-Apt-CEA complex, which dissociates from GO. Then, the CL catalyzed by HRP-Apt-CEA complex can be detected without any CRET, and the content of CEA can be estimated by the CL intensity. It has been proved that the interference issue resulted from free HRP-Apt is solved well by mixing GO firstly with HRP-Apt, which blocks the free HRP-Apt's CL signal due to CL quenching effect of GO; and the interference resulted from GO to CL is also solved by CE, then the sensitivity and accuracy can be greatly improved. Results also showed that the CL intensity had a linear relationship with the concentration of CEA in the range from 0.0654 to 6.54 ng/mL, and the limit of detection was approximately 4.8 pg/mL (S/N = 3). This proposed method with high specificity offers a new way for separation and determination of biomolecule, and has good potential in application of biochemistry and bioanalysis. Copyright © 2014 Elsevier B.V. All rights reserved.

A simple and sensitive flow injection method based on the catalytic activity of CdS quantum dots in an acidic permanganate chemiluminescence system for determination of formaldehyde in water and wastewater.

PubMed

Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza

2016-04-01

A simple and sensitive flow injection chemiluminescence (CL) method in which CdS quantum dots (QDs) enhanced the CL intensity of a KMnO4-formaldehyde (HCHO) reaction was offered for the determination of HCHO. This CL system was based on the catalytic activity of CdS QDs and their participation in the CL resonance energy transfer (CRET) phenomenon. A possible mechanism for the supplied CL system was proposed using the kinetic curves of the CL systems and the spectra of CL, photoluminescence (PL) and ultraviolet-visible (UV-Vis). The emanated CL intensity of the KMnO4-CdS QDs system was amplified in the presence of a trace level of HCHO. Based on this enhancement effect, a simple and sensitive flow injection CL method was suggested for the determination of HCHO concentration in environmental water and wastewater samples. Under selected optimized experimental conditions, the increased CL intensity was proportional to the HCHO concentration in the range of 0.03-4.5 μg L(-1) and 4.5-10.0 μg L(-1). The detection limits (3σ) were 0.0003 μg L(-1) and 1.2 μg L(-1). The relative standard deviations (RSD%) for eleven replicate determinations of 4.0 μg L(-1) HCHO were 2.2%. Furthermore, the feasibility of the developed method was investigated via the determination of HCHO concentration in environmental water and wastewater samples.

Stimulus-response mesoporous silica nanoparticle-based chemiluminescence biosensor for cocaine determination.

PubMed

Chen, Zhonghui; Tan, Yue; Xu, Kefeng; Zhang, Lan; Qiu, Bin; Guo, Longhua; Lin, Zhenyu; Chen, Guonan

2016-01-15

Mesoporous silica nanoparticles (MSN) based controlled release system had been coupled with diverse detection technologies to establish biosensors for different targets. Chemiluminescence (CL) system of luminol/H2O2 owns the characters of simplicity, low cost and high sensitivity, but the targets of which are mostly focused on some oxidants or which can participate in a chemical reaction that yields a product with a role in the CL reaction. In this study, chemiluminescent detection technique had been coupled with mesoporous silica-based controlled released system for the first time to develop a sensitive biosensor for the target which does not cause effect to the CL system itself. Cocaine had been chosen a model target, the MSN support was firstly loaded with glucose, then the positively charged MSN interacted with negatively charged oligonucleotides (the aptamer cocaine) to close the mesopores of MSN. At the present of target, cocaine binds with its aptamer with high affinity; the flexible linear aptamer structured will become stems structured through currently well-defined non-Waston-Crick interactions and causes the releasing of entrapped glucose into the solution. With the assistant of glucose oxidase (GOx), the released glucose can react with the dissolved oxgen to produce gluconic acid and H2O2, the latter can enhance the CL of luminol in the NaOH solution. The enhanced CL intensity has a relationship with the cocaine concentration in the range of 5.0-60μM with the detection limit of 1.43μM. The proposed method had been successfully applied to detect cocaine in serum samples with high selectivity. The same strategy can be applied to develop biosensors for different targets. Copyright © 2015 Elsevier B.V. All rights reserved.

Thirst Increases Chorda Tympani Responses to Sodium Chloride.

PubMed

Mast, Thomas G; Breza, Joseph M; Contreras, Robert J

2017-10-01

In nature, water is present as a low-salt solution, thus we hypothesized that thirst would increase taste responses to low-salt solutions. We investigated the effect of thirst on the 2 different salt detection mechanisms present in the rat chorda tympani (CT) nerve. The first mechanism is dependent upon the epithelial sodium channel (ENaC), is blocked by benzamil, and is specific to the cation sodium. The second mechanism, while undefined, is independent of ENaC, and detects multiple cations. We expected thirst to increase benzamil-sensitive sodium responses due to mechanistically increasing the benzamil-sensitive ENaC. We recorded CT whole-nerve electrophysiological responses to lingual application of NaCl, KCl (30, 75, 150, 300, 500, and 600 mM), and imitation rainwater in both control and 24-h water-restricted male rats. NaCl solutions were presented in artificial saliva before and after lingual application of 5µM benzamil. Water restriction significantly increased the integrated CT responses to NaCl but not to KCl or imitation rainwater. Consistent with our hypothesis, only the benzamil-sensitive, and not the benzamil-insensitive, CT sodium response significantly increased. Additionally, CT responses to salt were recorded following induction of either osmotic or volemic thirst. Both thirsts significantly enhanced the integrated CT responses to NaCl and KCl, but not imitation rainwater. Interestingly, osmotic and volemic thirsts increased CT responses by increasing both the benzamil-sensitive and benzamil-insensitive CT sodium responses. We propose that thirst increases the sensitivity of the CT nerve to sodium. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chemiluminescent detection of cell apoptosis enzyme by gold nanoparticle-based resonance energy transfer assay.

PubMed

Huang, Xiangyi; Liang, Yiran; Ruan, Lingao; Ren, Jicun

2014-09-01

We report a new chemiluminescence resonance energy transfer (CRET) technique, using gold nanoparticles (AuNPs) as efficient energy acceptor, for homogeneous measurement of cell apoptosis enzyme with high sensitivity. In the design of the CRET system, we chose the highly sensitive chemiluminescence (CL) reaction between luminol and hydrogen peroxide catalysed by horseradish peroxidase (HRP) because the CL spectrum of luminol (λ max 425 nm) partially overlaps the visible absorption bands of AuNPs. In this system, the peptide substrate (DEVD) of caspase 3 was linked to the AuNP surface by Au-S linkage. HRP was attached to the AuNP surface by means of a bridge formed by the streptavidin-biotin reaction. CRET occurred as a result of formation of AuNP-peptide-biotin-streptavidin-HRP complexes. The CL of luminol was significantly reduced, because of the quenching effect of AuNPs. The quenched CL was recovered after cleavage of DEVD by caspase 3, an enzyme involved in the apoptotic process. Experimental conditions were systematically investigated. Under the optimum conditions the increase of the CL signal was linearly dependent on caspase 3 concentration within the concentration range 25 pmol L(-1) to 800 pmol L(-1) and the detection limit of caspase 3 was as low as 20 pmol L(-1), one order of magnitude lower than for FRET sensors based on graphene oxides. Our method was successfully used to detect drug-induced apoptosis of cells. This approach is expected to be extended to other assays, i.e., using other enzymes, analytes, CL substances, and even other nanoparticles (e.g., quantum dots and graphene).

Highly sensitive glucose biosensor based on the effective immobilization of glucose oxidase/carbon-nanotube and gold nanoparticle in nafion film and peroxyoxalate chemiluminescence reaction of a new fluorophore.

PubMed

Zargoosh, Kiomars; Chaichi, Mohammad Javad; Shamsipur, Mojtaba; Hossienkhani, Saman; Asghari, Sakineh; Qandalee, Mohammad

2012-05-15

A novel glucose biosensor based on the chemiluminescence (CL) detection of enzymatically generated H(2)O(2) was constructed by the effective immobilization of glucose oxidase (GOD)/carbon-nanotubes (CNTs)/gold nanoparticles (GNPs) in nafion film on graphite support. The influences of various experimental parameters such as solution pH, the action time of the enzyme, interferents and the concentration of CL reagents were investigated. Carbon nanotubes and gold nanoparticles offer excellent catalytic activity toward hydrogen peroxide generation in enzymatic reaction between glucose oxidase and glucose, which would enable sensitive determination of glucose. Under the optimum condition, the linear response range of glucose was found to be 2.25 × 10(-6) to 1.75 × 10(-4 ) mol L(-1), and the detection limit (defined as the concentration that could be detected at the signal-to-noise ratio of 3) was 1.00 × 10(-6) mol L(-1). The CL biosensor exhibited good storage stability, i.e., 80% of its initial response was retained after 10 days storage at pH 7.0. The present CL biosensor has been used to determine the glucose concentrations in real serum and urine samples with satisfactory results. Copyright © 2011 Elsevier B.V. All rights reserved.

A novel dual-ratiometric-response fluorescent probe for SO2/ClO- detection in cells and in vivo and its application in exploring the dichotomous role of SO2 under the ClO- induced oxidative stress.

PubMed

Dou, Kun; Fu, Qiang; Chen, Guang; Yu, Fabiao; Liu, Yuxia; Cao, Ziping; Li, Guoliang; Zhao, Xianen; Xia, Lian; Chen, Lingxin; Wang, Hua; You, Jinmao

2017-07-01

Intracellular reactive sulfur species and reactive oxygen species play vital roles in immunologic mechanism. As an emerging signal transmitter, SO 2 can be generated as the anti-oxidant, while SO 2 is also a potential oxidative stress-inducer in organism. Aiming to elucidate in-depth the dichotomous role of SO 2 under oxidative stress, we designed a dual-response fluorescent probe that enabled the respective or successive detection of SO 2 and ClO - . The probe itself emits the red fluorescence (625 nm) which can largely switch to blue (410 nm) and green fluorescence (500 nm) respectively in response to SO 2 and ClO - , allowing the highly selective and accurate ratiometric quantification for both SO 2 and ClO - in cells. Moreover the ultrafast (SO 2 : <60 s; ClO - : within sec) and highly sensitive (detection limits: SO 2 : 3.5 nM; ClO - : 12.5 nM) detection were achieved. With the robust applicability, the developed probe was successfully used to quantify SO 2 and endogenous ClO - in respectively the HeLa cells and the RAW 264.7 cells, as well as to visualize the dynamic of SO 2 /ClO - in zebrafish. The fluorescent imaging studies and flow cytometry analysis confirmed the burst-and-depletion and meanwhile the oxidative-and-antioxidative effects of intracellular SO 2 under the NaClO induced oxidative stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

On the use of L-012, a luminol-based chemiluminescent probe, for detecting superoxide and identifying inhibitors of NADPH oxidase: A re-evaluation

PubMed Central

Zielonka, Jacek; Lambeth, J. David; Kalyanaraman, Balaraman

2014-01-01

L-012, a luminol-based chemiluminescent (CL) probe, is widely used in vitro and in vivo to detect NADPH oxidase (Nox)-derived superoxide (O2·−) and identify Nox inhibitors. Yet understanding of the free radical chemistry of L-012 probe is still lacking. We report that peroxidase and H2O2 induce superoxide dismutase (SOD)-sensitive, L-012-derived CL in the presence of oxygen. O2·− alone does not react with L-012 to emit luminescence. Self-generated O2·− during oxidation of L-012 and luminol-analogs artifactually induce CL inhibitable by SOD. These aspects make assays based on luminol analogs less than ideal for specific detection and identification of O2·− and NOX inhibitors. PMID:24080119

Colorimetric Humidity Sensors Based on Electrospun Polyamide/CoCl2 Nanofibrous Membranes.

PubMed

You, Ming-Hao; Yan, Xu; Zhang, Jun; Wang, Xiao-Xiong; He, Xiao-Xiao; Yu, Miao; Ning, Xin; Long, Yun-Ze

2017-12-01

Humidity indicators based on composite polyamide 66/cobalt chloride (PA66/CoCl 2 ) nanofibrous membranes (NFMs) were successfully fabricated by electrospinning. A series of NFMs with various weight percentage of CoCl 2 to PA66 were prepared, and their humidity sensitivity based on color changing and quartz crystal microbalance (QCM) were studied. Due to the color change property of cobalt chloride, the as-spun composite NFMs show obviously macroscopic color change from blue to pink as relative humidity (RH) increasing from 12.4 to 97.2%. Moreover, the QCM detection showed a linear dependence on the RH changing and exhibited short response/recovery time (less than 65.4 s/11 s), small hysteresis (less than 11%), good reproducibility, and stability. Owing to the above double sensitive mechanism on RH, the PA66/CoCl 2 composite NFM may show great potential applications from meticulous to coarse.

Colorimetric Humidity Sensors Based on Electrospun Polyamide/CoCl2 Nanofibrous Membranes

NASA Astrophysics Data System (ADS)

You, Ming-Hao; Yan, Xu; Zhang, Jun; Wang, Xiao-Xiong; He, Xiao-Xiao; Yu, Miao; Ning, Xin; Long, Yun-Ze

2017-05-01

Humidity indicators based on composite polyamide 66/cobalt chloride (PA66/CoCl2) nanofibrous membranes (NFMs) were successfully fabricated by electrospinning. A series of NFMs with various weight percentage of CoCl2 to PA66 were prepared, and their humidity sensitivity based on color changing and quartz crystal microbalance (QCM) were studied. Due to the color change property of cobalt chloride, the as-spun composite NFMs show obviously macroscopic color change from blue to pink as relative humidity (RH) increasing from 12.4 to 97.2%. Moreover, the QCM detection showed a linear dependence on the RH changing and exhibited short response/recovery time (less than 65.4 s/11 s), small hysteresis (less than 11%), good reproducibility, and stability. Owing to the above double sensitive mechanism on RH, the PA66/CoCl2 composite NFM may show great potential applications from meticulous to coarse.

Analytical sensitivity and specificity of a loop-mediated isothermal amplification (LAMP) kit prototype for detection of Trypanosoma cruzi DNA in human blood samples.

PubMed

Besuschio, Susana A; Llano Murcia, Mónica; Benatar, Alejandro F; Monnerat, Severine; Cruz, Israel; Picado, Albert; Curto, María de Los Ángeles; Kubota, Yutaka; Wehrendt, Diana P; Pavia, Paula; Mori, Yasuyoshi; Puerta, Concepción; Ndung'u, Joseph M; Schijman, Alejandro G

2017-07-01

This study aimed to assess analytical parameters of a prototype LAMP kit that was designed for detection of Trypanosoma cruzi DNA in human blood. The prototype is based on the amplification of the highly repetitive satellite sequence of T.cruzi in microtubes containing dried reagents on the inside of the caps. The reaction is carried out at 65°C during 40 minutes. Calcein allows direct detection of amplified products with the naked eye. Inclusivity and selectivity were tested in purified DNA from Trypanosoma cruzi stocks belonging to the six discrete typing units (DTUs), in DNA from other protozoan parasites and in human DNA. Analytical sensitivity was estimated in serial dilutions of DNA samples from Sylvio X10 (Tc I) and CL Brener (Tc VI) stocks, as well as from EDTA-treated or heparinized blood samples spiked with known amounts of cultured epimastigotes (CL Brener). LAMP sensitivity was compared after DNA extraction using commercial fiberglass columns or after "Boil & Spin" rapid preparation. Moreover, the same DNA and EDTA-blood spiked samples were subjected to standardized qPCR based on the satellite DNA sequence for comparative purposes. A panel of peripheral blood specimens belonging to Chagas disease patients, including acute, congenital, chronic and reactivated cases (N = 23), as well as seronegative controls (N = 10) were evaluated by LAMP in comparison to qPCR. LAMP was able to amplify DNAs from T. cruzi stocks representative of the six DTUs, whereas it did not amplify DNAs from Leishmania sp, T. brucei sp, T. rangeli KPN+ and KPN-, P. falciparum and non-infected human DNA. Analytical sensitivity was 1x10-2 fg/μL of both CL Brener and Sylvio X10 DNAs, whereas qPCR detected up to 1x 10-1 fg/μL of CL Brener DNA and 1 fg/μl of Sylvio X10 DNA. LAMP detected 1x10-2 parasite equivalents/mL in spiked EDTA blood and 1x10-1 par.eq/mL in spiked heparinized blood using fiberglass columns for DNA extraction, whereas qPCR detected 1x10-2 par.eq./mL in EDTA blood. Boil & Spin extraction allowed detection of 1x10-2 par.eq /mL in spiked EDTA blood and 1 par.eq/ml in heparinized blood. LAMP was able to detect T.cruzi infection in peripheral blood samples collected from well-characterised seropositive patients, including acute, congenital, chronic and reactivated Chagas disease. To our knowledge, this is the first report of a prototype LAMP kit with appropriate analytical sensitivity for diagnosis of Chagas disease patients, and potentially useful for monitoring treatment response.

Analytical sensitivity and specificity of a loop-mediated isothermal amplification (LAMP) kit prototype for detection of Trypanosoma cruzi DNA in human blood samples

PubMed Central

Besuschio, Susana A.; Llano Murcia, Mónica; Benatar, Alejandro F.; Monnerat, Severine; Cruz, Israel; Picado, Albert; Curto, María de los Ángeles; Kubota, Yutaka; Wehrendt, Diana P.; Pavia, Paula; Mori, Yasuyoshi; Puerta, Concepción; Ndung'u, Joseph M.

2017-01-01

This study aimed to assess analytical parameters of a prototype LAMP kit that was designed for detection of Trypanosoma cruzi DNA in human blood. The prototype is based on the amplification of the highly repetitive satellite sequence of T.cruzi in microtubes containing dried reagents on the inside of the caps. The reaction is carried out at 65°C during 40 minutes. Calcein allows direct detection of amplified products with the naked eye. Inclusivity and selectivity were tested in purified DNA from Trypanosoma cruzi stocks belonging to the six discrete typing units (DTUs), in DNA from other protozoan parasites and in human DNA. Analytical sensitivity was estimated in serial dilutions of DNA samples from Sylvio X10 (Tc I) and CL Brener (Tc VI) stocks, as well as from EDTA-treated or heparinized blood samples spiked with known amounts of cultured epimastigotes (CL Brener). LAMP sensitivity was compared after DNA extraction using commercial fiberglass columns or after “Boil & Spin” rapid preparation. Moreover, the same DNA and EDTA-blood spiked samples were subjected to standardized qPCR based on the satellite DNA sequence for comparative purposes. A panel of peripheral blood specimens belonging to Chagas disease patients, including acute, congenital, chronic and reactivated cases (N = 23), as well as seronegative controls (N = 10) were evaluated by LAMP in comparison to qPCR. LAMP was able to amplify DNAs from T. cruzi stocks representative of the six DTUs, whereas it did not amplify DNAs from Leishmania sp, T. brucei sp, T. rangeli KPN+ and KPN-, P. falciparum and non-infected human DNA. Analytical sensitivity was 1x10-2 fg/μL of both CL Brener and Sylvio X10 DNAs, whereas qPCR detected up to 1x 10−1 fg/μL of CL Brener DNA and 1 fg/μl of Sylvio X10 DNA. LAMP detected 1x10-2 parasite equivalents/mL in spiked EDTA blood and 1x10-1 par.eq/mL in spiked heparinized blood using fiberglass columns for DNA extraction, whereas qPCR detected 1x10-2 par.eq./mL in EDTA blood. Boil & Spin extraction allowed detection of 1x10-2 par.eq /mL in spiked EDTA blood and 1 par.eq/ml in heparinized blood. LAMP was able to detect T.cruzi infection in peripheral blood samples collected from well-characterised seropositive patients, including acute, congenital, chronic and reactivated Chagas disease. To our knowledge, this is the first report of a prototype LAMP kit with appropriate analytical sensitivity for diagnosis of Chagas disease patients, and potentially useful for monitoring treatment response. PMID:28727723

A flow injection chemiluminescence method for determination of nalidixic acid based on KMnO4-morin sensitized with CdS quantum dots

NASA Astrophysics Data System (ADS)

Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza; Joo, Sang Woo

2016-02-01

A simple and sensitive flow injection chemiluminescence (CL) method was developed for determination of nalidixic acid by application of CdS quantum dots (QDs) in KMnO4-morin CL system in acidic medium. Optical and structural features of L-cysteine capped CdS quantum dots which were synthesized via hydrothermal approach were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and ultraviolet-visible (UV-Vis) spectroscopy. Moreover, the potential mechanism of the proposed CL method was described using the results of the kinetic curves of CL systems, the spectra of CL, PL and UV-Vis analyses. The CL intensity of the KMnO4-morin-CdS QDs system was considerably increased in the presence of nalidixic acid. Under the optimum condition, the enhanced CL intensity was linearly proportional to the concentration of nalidixic acid in the range of 0.0013 to 21.0 mg L- 1, with a detection limit of (3σ) 0.003 mg L- 1. Also, the proposed CL method was utilized for determination of nalidixic acid in environmental water samples, and commercial pharmaceutical formulation to approve its applicability. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) method was utilized for determination of nalidixic acid and the results of real sample analysis by two proposed methods were compared. Comparison the analytical features of these methods represented that the proposed CL method is preferable to CD-IMS method for determination of nalidixic acid due to its high sensitivity and precision.

A flow injection chemiluminescence method for determination of nalidixic acid based on KMnO₄-morin sensitized with CdS quantum dots.

PubMed

Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza; Joo, Sang Woo

2016-02-05

A simple and sensitive flow injection chemiluminescence (CL) method was developed for determination of nalidixic acid by application of CdS quantum dots (QDs) in KMnO4-morin CL system in acidic medium. Optical and structural features of L-cysteine capped CdS quantum dots which were synthesized via hydrothermal approach were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and ultraviolet-visible (UV-Vis) spectroscopy. Moreover, the potential mechanism of the proposed CL method was described using the results of the kinetic curves of CL systems, the spectra of CL, PL and UV-Vis analyses. The CL intensity of the KMnO4-morin-CdS QDs system was considerably increased in the presence of nalidixic acid. Under the optimum condition, the enhanced CL intensity was linearly proportional to the concentration of nalidixic acid in the range of 0.0013 to 21.0 mg L(-1), with a detection limit of (3σ) 0.003 mg L(-1). Also, the proposed CL method was utilized for determination of nalidixic acid in environmental water samples, and commercial pharmaceutical formulation to approve its applicability. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) method was utilized for determination of nalidixic acid and the results of real sample analysis by two proposed methods were compared. Comparison the analytical features of these methods represented that the proposed CL method is preferable to CD-IMS method for determination of nalidixic acid due to its high sensitivity and precision. Copyright © 2015 Elsevier B.V. All rights reserved.

Highly selective and sensitive chemiluminescence biosensor for adenosine detection based on carbon quantum dots catalyzing luminescence released from aptamers functionalized graphene@magnetic β-cyclodextrin polymers.

PubMed

Sun, Yuanling; Ding, Chaofan; Lin, Yanna; Sun, Weiyan; Liu, Hao; Zhu, Xiaodong; Dai, Yuxue; Luo, Chuannan

2018-08-15

In this work, a highly selective and sensitive chemiluminescence (CL) biosensor was prepared for adenosine (AD) detection based on carbon quantum dots (CQDs) catalyzing the CL system of luminol-H 2 O 2 under alkaline environment and CQDs was released from the surface of AD aptamers functionalized graphene @ magnetic β-cyclodextrin polymers (GO@Fe 3 O 4 @β-CD@A-Apt). Firstly, GO@Fe 3 O 4 @β-CD and CQDs were prepared and characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), UV-Vis absorption spectra (UV), fluorescence spectra (FL), fourier transform infrared (FTIR) and X-ray powder diffraction (XRD). For GO@Fe 3 O 4 @β-CD, Fe 3 O 4 was easy to separate, GO had good biocompatibility and large specific surface area, and β-CD further increased the specific surface area of the adenosine polymers (A-Apt) to provided larger binding sites to A-Apt. Then, A-Apt was modified on the surface of GO@Fe 3 O 4 @β-CD while CQDs was modified by ssDNA (a single stranded DNA partially complementary to A-Apt). The immobilization property (GO@Fe 3 O 4 @β-CD to A-Apt) and the adsorption property (GO@Fe 3 O 4 @β-CD@A-Apt to CQDs-ssDNA) were sequentially researched. The base-supported chain-like polymers - GO@Fe 3 O 4 @β-CD@A-Apt/CQDs-ssDNA was successfully obtained. When AD existed, CQDs-ssDNA was released from the surface of GO@Fe 3 O 4 @β-CD@A-Apt and catalyzed CL. After that, under optimized CL conditions, AD could be measured with the linear concentration range of 5.0 × 10 -13 -5.0 × 10 -9 mol/L and the detection limit of 2.1 × 10 -13 mol/L (3δ) while the relative standard deviation (RSD) was 1.4%. Finally, the GO@Fe 3 O 4 @β-CD@A-Apt/CQDs-ssDNA-CL biosensor was used for the determination of AD in urine samples and recoveries ranged from 98.6% to 101.0%. Those satisfactory results illustrated the proposed CL biosensor could achieve highly selective, sensitive and reliable detection of AD and revealed potential application for AD detection in monitoring and diagnosis of human cancers. Copyright © 2018 Elsevier B.V. All rights reserved.

Assessment of Myeloperoxidase Activity by the Conversion of Hydroethidine to 2-Chloroethidium*

PubMed Central

Maghzal, Ghassan J.; Cergol, Katie M.; Shengule, Sudhir R.; Suarna, Cacang; Newington, Darren; Kettle, Anthony J.; Payne, Richard J.; Stocker, Roland

2014-01-01

Oxidants derived from myeloperoxidase (MPO) contribute to inflammatory diseases. In vivo MPO activity is commonly assessed by the accumulation of 3-chlorotyrosine (3-Cl-Tyr), although 3-Cl-Tyr is formed at low yield and is subject to metabolism. Here we show that MPO activity can be assessed using hydroethidine (HE), a probe commonly employed for the detection of superoxide. Using LC/MS/MS, 1H NMR, and two-dimensional NOESY, we identified 2-chloroethidium (2-Cl-E+) as a specific product when HE was exposed to hypochlorous acid (HOCl), chloramines, MPO/H2O2/chloride, and activated human neutrophils. The rate constant for HOCl-mediated conversion of HE to 2-Cl-E+ was estimated to be 1.5 × 105 m−1s−1. To investigate the utility of 2-Cl-E+ to assess MPO activity in vivo, HE was injected into wild-type and MPO-deficient (Mpo−/−) mice with established peritonitis or localized arterial inflammation, and tissue levels of 2-Cl-E+ and 3-Cl-Tyr were then determined by LC/MS/MS. In wild-type mice, 2-Cl-E+ and 3-Cl-Tyr were detected readily in the peritonitis model, whereas in the arterial inflammation model 2-Cl-E+ was present at comparatively lower concentrations (17 versus 0.3 pmol/mg of protein), and 3-Cl-Tyr could not be detected. Similar to the situation with 3-Cl-Tyr, tissue levels of 2-Cl-E+ were decreased substantially in Mpo−/− mice, indicative of the specificity of the assay. In the arterial inflammation model, 2-Cl-E+ was absent from non-inflamed arteries and blood, suggesting that HE oxidation occurred locally in the inflamed artery. Our data suggest that the conversion of exogenous HE to 2-Cl-E+ may be a useful selective and sensitive marker for MPO activity in addition to 3-Cl-Tyr. PMID:24436331

Development of a tape transport bacterial detection system

NASA Technical Reports Server (NTRS)

Witz, S.; Hartung, W. H.

1972-01-01

The feasibility of a tape transport chemiluminescence system for bacterial monitoring of regenerated water was demonstrated using a manually operated laboratory breadboard. The principle of detection is based on measuring the increase in chemiluminescence produced by the catalytic action of bacterial porphyrins on a luminol-hydrogen peroxide mixture. Viable organisms are distinguished from nonviable by comparing the signals of incubated and unincubated water samples. Using optimized protocols, sensitivities were obtained with 400 ml suspensions of E. coli and Cl. sporogenes. The sensitivity of the unincubated cycle E. coli (aerobe) was found to be 30 to 35 cells/m1, and that of the Cl. sporogenes (anaerobe) was 1000 to 10,000 cells/m1. The lower sensitivity toward Cl. sporogenes is attributed to several factors, namely the lower cytochrome content, the tendency to sporulate, long lag periods and the lower growth rate of Clostridia in general. The operational procedures used for processing the incubated and unincubated samples involved the following sequence: (1) concentrating the sample by filtration through a membrane filter, (2) washing with Dextrose-Thioglycollate Broth (3) incubating (0 to 4 hrs as required), (4) washing with 4M Urea, and (5) reacting with reagent in front of a photomultiplier tube. The signal output was recorded on a strip chart recorder.

Sensitive diagnosis of cutaneous leishmaniasis by lesion swab sampling coupled to qPCR

PubMed Central

ADAMS, EMILY R.; GOMEZ, MARIA ADELAIDA; SCHESKE, LAURA; RIOS, RUBY; MARQUEZ, RICARDO; COSSIO, ALEXANDRA; ALBERTINI, AUDREY; SCHALLIG, HENK; SARAVIA, NANCY GORE

2015-01-01

SUMMARY Variation in clinical accuracy of molecular diagnostic methods for cutaneous leishmaniasis (CL) is commonly observed depending on the sample source, the method of DNA recovery and the molecular test. Few attempts have been made to compare these variables. Two swab and aspirate samples from lesions of patients with suspected CL (n = 105) were evaluated alongside standard diagnosis by microscopic detection of amastigotes or culture of parasites from lesion material. Three DNA extraction methods were compared: Qiagen on swab and aspirate specimens, Isohelix on swabs and Boil/Spin of lesion aspirates. Recovery of Leishmania DNA was evaluated for each sample type by real-time polymerase chain reaction detection of parasitic 18S rDNA, and the diagnostic accuracy of the molecular method determined. Swab sampling combined with Qiagen DNA extraction was the most efficient recovery method for Leishmania DNA, and was the most sensitive (98%; 95% CI: 91–100%) and specific (84%; 95% CI: 64–95%) approach. Aspirated material was less sensitive at 80% (95% CI: 70–88%) and 61% (95% CI: 50–72%) when coupled to Qiagen or Boil-Spin DNA extraction, respectively. Swab sampling of lesions was painless, simple to perform and coupled with standardized DNA extraction enhances the feasibility of molecular diagnosis of CL. PMID:25111885

Proximity hybridization-regulated chemiluminescence resonance energy transfer for homogeneous immunoassay.

PubMed

Liu, Mengmeng; Wu, Jie; Yang, Kaili; Zong, Chen; Lei, Jianping; Ju, Huangxian

2016-07-01

Chemiluminescence resonance energy transfer (CRET) and the proximity ligation assay have been widely used in design of sensors for the bioanalysis. Here, a wash-free and homogeneous strategy was proposed to detect carcino-embryonic antigen (CEA) based on proximity hybridization-regulated CRET. The Cy5 demonstrated strong chemiluminescence (CL) via the oxidation of TCPO in the presence of H2O2 and energy transfer between excited TCPO and Cy5. Graphene oxide (GO) as an excellent quencher was used to produce the "Signal off" mode that little CL emission was observed through CRET between GO and the Cy5-labelled DNA3. Once CEA was introduced, the target-induced proximity hybridization occurred to form a proximate complex, which inhibited the CRET by preventing GO from absorbing Cy5-labelled DNA3. Furthermore, taking advantage of nicking endonuclease Nt.BbvCI for in situ recycling, the signal could be further amplified for highly sensitive CL detection. Our results showed that this strategy enabled a specific response to CEA with a detection range of 5 orders of magnitude, along with a detection limit of 3.2pg mL(-1). Apart from its easy operation, high sensitivity and acceptable accuracy, the proposed method needed only 0.3μL of sample, indicating its great opportunity for commercial application. Copyright © 2016 Elsevier B.V. All rights reserved.

The alteration of mRNA expression of SOD and GPX genes, and proteins in tomato (Lycopersicon esculentum Mill) under stress of NaCl and/or ZnO nanoparticles.

PubMed

Alharby, Hesham F; Metwali, Ehab M R; Fuller, Michael P; Aldhebiani, Amal Y

2016-11-01

Five cultivars of tomato having different levels of salt stress tolerance were exposed to different treatments of NaCl (0, 3 and 6 g L -1 ) and ZnO-NPs (0, 15 and 30 mg L -1 ). Treatments with NaCl at both 3 and 6 g L -1 suppressed the mRNA levels of superoxide dismutase (SOD) and glutathione peroxidase (GPX) genes in all cultivars while plants treated with ZnO-NPs in the presence of NaCl, showed increments in the mRNA expression levels. This indicated that ZnO-NPs had a positive response on plant metabolism under salt stress. Superior expression levels of mRNA were observed in the salt tolerant cultivars, Sandpoint and Edkawy while the lowest level was detected in the salt sensitive cultivar, Anna Aasa. SDS-PAGE showed clear differences in patterns of protein expression among the cultivars. A negative protein marker for salt sensitivity and ZnO-NPs was detected in cv. Anna Aasa at a molecular weight of 19.162 kDa, while the tolerant cultivar Edkawy had two positive markers at molecular weights of 74.991 and 79.735 kDa.

Release of Gd-ions from peralkaline borosilicate glass in pure water for neutrino detection in Water-Cherenkov Detectors

NASA Astrophysics Data System (ADS)

Dongol, R.; Sundaram, S. K.

2017-09-01

The addition of Gadolinium (Gd)-based salt, specially GdCl3, in the Water Cherenkov Detectors (WCDs) enhances the sensitivity to neutrino detection. However, the unwanted Cl-based byproducts, significantly reduces the transparency of water and sensitivity of WCDs. An alternative method, to introduce Gd-ions in the WCDs, is through Gd-release from a custom designed Gd-doped glass, when in contact with water. This can potentially eliminate the use of Gd-based salts and byproducts. In this work, we report the Gd-ions release for a Gd-doped peralkaline (Na/Al > 1) borosilicate glass, which closely represents photomultiplier tube (PMT) glass composition used in WCDs. The purpose of the paper is to show that the Gd-ion release from a custom designed glass in the form of beads or powders is feasible and could be used as a controlled Gd-source in future WCDs to enhance neutrino detection. In addition, we present our results of Gd-solubility in the base glass composition.

Enhanced chemiluminescent detection scheme for trace vapor sensing in pneumatically-tuned hollow core photonic bandgap fibers.

PubMed

Stolyarov, Alexander M; Gumennik, Alexander; McDaniel, William; Shapira, Ofer; Schell, Brent; Sorin, Fabien; Kuriki, Ken; Benoit, Gilles; Rose, Aimee; Joannopoulos, John D; Fink, Yoel

2012-05-21

We demonstrate an in-fiber gas phase chemical detection architecture in which a chemiluminescent (CL) reaction is spatially and spectrally matched to the core modes of hollow photonic bandgap (PBG) fibers in order to enhance detection efficiency. A peroxide-sensitive CL material is annularly shaped and centered within the fiber's hollow core, thereby increasing the overlap between the emission intensity and the intensity distribution of the low-loss fiber modes. This configuration improves the sensitivity by 0.9 dB/cm compared to coating the material directly on the inner fiber surface, where coupling to both higher loss core modes and cladding modes is enhanced. By integrating the former configuration with a custom-built optofluidic system designed for concomitant controlled vapor delivery and emission measurement, we achieve a limit-of-detection of 100 parts per billion (ppb) for hydrogen peroxide vapor. The PBG fibers are produced by a new fabrication method whereby external gas pressure is used as a control knob to actively tune the transmission bandgaps through the entire visible range during the thermal drawing process.

Detection of adenosine triphosphate through polymerization-induced aggregation of actin-conjugated gold/silver nanorods.

PubMed

Liao, Yu-Ju; Shiang, Yen-Chun; Chen, Li-Yi; Hsu, Chia-Lun; Huang, Chih-Ching; Chang, Huan-Tsung

2013-11-08

We have developed a simple and selective nanosensor for the optical detection of adenosine triphosphate (ATP) using globular actin-conjugated gold/silver nanorods (G-actin-Au/Ag NRs). By simply mixing G-actin and Au/Ag NRs (length ~56 nm and diameter ~12 nm), G-actin-Au/Ag NRs were prepared which were stable in physiological solutions (25 mM Tris-HCl, 150 mM NaCl, 5.0 mM KCl, 3.0 mM MgCl2 and 1.0 mM CaCl2; pH 7.4). Introduction of ATP into the G-actin-Au/Ag NR solutions in the presence of excess G-actin induced the formation of filamentous actin-conjugated Au/Ag NR aggregates through ATP-induced polymerization of G-actin. When compared to G-actin-modified spherical Au nanoparticles having a size of 13 nm or 56 nm, G-actin-Au/Ag NRs provided better sensitivity for ATP, mainly because the longitudinal surface plasmon absorbance of the Au/Ag NR has a more sensitive response to aggregation. This G-actin-Au/Ag NR probe provided high sensitivity (limit of detection 25 nM) for ATP with remarkable selectivity (>10-fold) over other adenine nucleotides (adenosine, adenosine monophosphate and adenosine diphosphate) and nucleoside triphosphates (guanosine triphosphate, cytidine triphosphate and uridine triphosphate). It also allowed the determination of ATP concentrations in plasma samples without conducting tedious sample pretreatments; the only necessary step was simple dilution. Our experimental results are in good agreement with those obtained from a commercial luciferin-luciferase bioluminescence assay. Our simple, sensitive and selective approach appears to have a practical potential for the clinical diagnosis of diseases (e.g. cystic fibrosis) associated with changes in ATP concentrations.

Detection of adenosine triphosphate through polymerization-induced aggregation of actin-conjugated gold/silver nanorods

NASA Astrophysics Data System (ADS)

Liao, Yu-Ju; Shiang, Yen-Chun; Chen, Li-Yi; Hsu, Chia-Lun; Huang, Chih-Ching; Chang, Huan-Tsung

2013-11-01

We have developed a simple and selective nanosensor for the optical detection of adenosine triphosphate (ATP) using globular actin-conjugated gold/silver nanorods (G-actin-Au/Ag NRs). By simply mixing G-actin and Au/Ag NRs (length ˜56 nm and diameter ˜12 nm), G-actin-Au/Ag NRs were prepared which were stable in physiological solutions (25 mM Tris-HCl, 150 mM NaCl, 5.0 mM KCl, 3.0 mM MgCl2 and 1.0 mM CaCl2; pH 7.4). Introduction of ATP into the G-actin-Au/Ag NR solutions in the presence of excess G-actin induced the formation of filamentous actin-conjugated Au/Ag NR aggregates through ATP-induced polymerization of G-actin. When compared to G-actin-modified spherical Au nanoparticles having a size of 13 nm or 56 nm, G-actin-Au/Ag NRs provided better sensitivity for ATP, mainly because the longitudinal surface plasmon absorbance of the Au/Ag NR has a more sensitive response to aggregation. This G-actin-Au/Ag NR probe provided high sensitivity (limit of detection 25 nM) for ATP with remarkable selectivity (>10-fold) over other adenine nucleotides (adenosine, adenosine monophosphate and adenosine diphosphate) and nucleoside triphosphates (guanosine triphosphate, cytidine triphosphate and uridine triphosphate). It also allowed the determination of ATP concentrations in plasma samples without conducting tedious sample pretreatments; the only necessary step was simple dilution. Our experimental results are in good agreement with those obtained from a commercial luciferin-luciferase bioluminescence assay. Our simple, sensitive and selective approach appears to have a practical potential for the clinical diagnosis of diseases (e.g. cystic fibrosis) associated with changes in ATP concentrations.

Dysprosium-sensitized chemiluminescence system for the determination of enoxacin in pharmaceutical preparations and biological fluids with flow-injection sampling.

PubMed

Sun, Han-wen; Wu, Yuan-yuan; Li, Li-qing

2009-03-01

A novel trivalence dysprosium(Dy(3+))-sensitized chemiluminescence method was developed for the first time for the determination of enoxacin (ENX) using flow-injection sampling based on the chemiluminescence (CL) associated with the reaction of the Dy(3+)-cerium(Ce(IV))-S(2)O(3) (2-)-ENX system and the Dy(3+)-MnO(4) (-) S(2)O(3) (2-)-ENX system. The analytical conditions for CL emission were investigated and optimized. The relationship between the CL intensity of ENX and its concentration has good linearity, with a correlation coefficient of 0.9984-0.9994. The limit of detection (LOD, 3sigma) was 0.20 ng/mL for the Dy(3+)-ENX-S(2)O(3)(2-)-Ce(IV)-H(2)SO(4) system and 0.22 ng/mL for the Dy(3+)-ENX-S(2)O(3)(2-)-MnO(4) (-)-HNO(3) system. The relative standard deviation (RSD, n = 11) was 1.8% for 11 determinations of 60 ng/mL ENX. The proposed method was applied to the analysis of ENX in injections, serum and urine samples with a recovery of 98%-105%. A possible mechanism for this sensitized CL reaction is discussed by comparing the CL spectra with the fluorescence emission spectra. The proposed method represents a wide linear range, high sensitivity and accuracy, and can be used for the routine determination of ENX in pharmaceutical preparations and biological fluids. Copyright 2009 John Wiley & Sons, Ltd.

Sensitive determination of 2-methoxyestradiol in pharmaceutical preparations and serum samples using flow injection chemiluminescence.

PubMed

Yao, Hanchun; Zhang, Min; Zeng, Wenyuan; Zeng, Xiaoying; Zhang, Zhenzhong

2014-05-01

A rapid and sensitive flow injection chemiluminescence (FI-CL) method is described for the determination of 2-methoxyestradiol (2ME) based on enhancement of the CL intensity from a potassium ferricyanide-calcein system in sodium hydroxide medium. The optimum conditions for the CL emission were investigated. Under optimized conditions, a linear calibration graph was obtained over the range 1.0 × 10(-8) to 1.0 × 10(-6) mol/L (r = 0.998) 2ME with a detection limit (3σ) of 5.4 × 10(-9) mol/L. The relative standard deviation (RSD) for 5.0 × 10(-7) mol/L 2ME was 1.7%. As a preliminary application, the proposed method was successfully applied to the determination of 2ME in injection solutions and serum samples. The possible CL mechanism was also proposed. Copyright © 2013 John Wiley & Sons, Ltd.

[Analysis of H2S/PH3/NH3/AsH3/Cl2 by Full-Spectral Flame Photometric Detector].

PubMed

Ding, Zhi-jun; Wang, Pu-hong; Li, Zhi-jun; Du, Bin; Guo, Lei; Yu, Jian-hua

2015-07-01

Flame photometric analysis technology has been proven to be a rapid and sensitive method for sulfur and phosphorus detection. It has been widely used in environmental inspections, pesticide detection, industrial and agricultural production. By improving the design of the traditional flame photometric detector, using grating and CCD sensor array as a photoelectric conversion device, the types of compounds that can be detected were expanded. Instead of a single point of characteristic spectral lines, full spectral information has been used for qualitative and quantitative analysis of H2S, PH3, NH3, AsH3 and Cl2. Combined with chemometric method, flame photometric analysis technology is expected to become an alternative fast, real-time on-site detection technology to simultaneously detect multiple toxic and harmful gases.

Polymerase Chain Reaction Detection of Leishmania kDNA from the Urine of Peruvian Patients with Cutaneous and Mucocutaneous Leishmaniasis

PubMed Central

Veland, Nicolas; Espinosa, Diego; Valencia, Braulio Mark; Ramos, Ana Pilar; Calderon, Flor; Arevalo, Jorge; Low, Donald E.; Llanos-Cuentas, Alejandro; Boggild, Andrea K.

2011-01-01

We hypothesized that Leishmania kDNA may be present in urine of patients with cutaneous leishmaniasis (CL). Urine samples and standard diagnostic specimens were collected from patients with skin lesions. kDNA polymerase chain reaction (PCR) was performed on samples from patients and 10 healthy volunteers from non-endemic areas. Eighty-six of 108 patients were diagnosed with CL and 18 (21%) had detectable Leishmania Viannia kDNA in the urine. Sensitivity and specificity were 20.9% (95% confidence interval [CI] 12.3–29.5%) and 100%. Six of 8 patients with mucocutaneous involvement had detectable kDNA in urine versus 12 of 78 patients with isolated cutaneous disease (P < 0.001). L. (V.) braziliensis (N = 3), L. (V.) guyanensis (N = 6), and L. (V.) peruviana (N = 3) were identified from urine. No healthy volunteer or patient with an alternate diagnosis had detectable kDNA in urine. Sensitivity of urine PCR is sub-optimal for diagnosis. On the basis of these preliminary data in a small number of patients, detectable kDNA in urine may identify less localized forms of infection and inform treatment decisions. PMID:21460009

Pyrophosphate as substrate for alkaline phosphatase activity: A convenient flow-injection chemiluminescence assay.

PubMed

Zhang, Qingfeng; Zhang, Cuiyun; Yang, Meiding; Yu, Donghong; Yu, Cong

2017-11-01

A sensitive and convenient flow-injection chemiluminescence (FI-CL) turn-on assay for alkaline phosphatase (ALP) activity without any label and synthesis is developed. Cu 2+ can catalyze the luminol-H 2 O 2 CL reaction. Pyrophosphate (PPi) can chelate Cu 2+ and therefore the Cu 2+ -mediated luminol-H 2 O 2 CL reaction is inhibited. The addition of ALP can catalyze the hydrolysis of PPi into phosphate ions, Cu 2+ is released and the chemiluminescence recovers. A detection limit of 1 mU/mL ALP is obtained. Copyright © 2017 John Wiley & Sons, Ltd.

Chest-lead ST-J amplitudes using arm electrodes as reference instead of the Wilson central terminal in smartphone ECG applications: Influence on ST-elevation myocardial infarction criteria fulfillment.

PubMed

Lindow, Thomas; Engblom, Henrik; Khoshnood, Ardavan; Ekelund, Ulf; Carlsson, Marcus; Pahlm, Olle

2018-05-07

"Smartphone 12-lead ECG" for the assessment of acute myocardial ischemia has recently been introduced. In the smartphone 12-lead ECG either the right or the left arm can be used as reference for the chest electrodes instead of the Wilson central terminal. These leads are labeled "CR leads" or "CL leads." We aimed to compare chest-lead ST-J amplitudes, using either CR or CL leads, to those present in the conventional 12-lead ECG, and to determine sensitivity and specificity for the diagnosis of STEMI for CR and CL leads. Five hundred patients (74 patients with ST elevation myocardial infarction (STEMI), 66 patients with nonischemic ST deviation and 360 controls) were included. Smartphone 12-lead ECG chest-lead ST-J amplitudes were calculated for both CR and CL leads. ST-J amplitudes were 9.1 ± 29 μV larger for CR leads and 7.7 ± 42 μV larger for CL leads than for conventional chest leads (V leads). Sensitivity and specificity were 94% and 95% for CR leads and 81% and 97% for CL leads when fulfillment of STEMI criteria in V leads was used as reference. In ischemic patients who met STEMI criteria in V leads, but not in limb leads, STEMI criteria were met with CR or CL leads in 91%. By the use of CR or CL leads, smartphone 12-lead ECG results in slightly lower sensitivity in STEMI detection. Therefore, the adjustment of STEMI criteria may be needed before application in clinical practice. © 2018 The Authors. Annals of Noninvasive Electrocardiology Published by Wiley Periodicals, Inc.

Flow-injection chemiluminescence analysis for sensitive determination of atenolol using cadmium sulfide quantum dots.

PubMed

Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza; Joo, Sang Woo

2016-03-15

A sensitive, rapid and simple flow-injection chemiluminescence (CL) system based on the light emitted from KMnO4-cadmium sulfide quantum dots (CdS QDs) reaction in the presence of cetyltrimethylammonium bromide (CTAB) in acidic medium was developed as a CL probe for the sensitive determination of atenolol. Optical and structural features of CdS QDs capped with l-cysteine, which synthesized via hydrothermal approach, were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and UV-Vis spectroscopy. The CL intensity of KMnO4-CdS QDs-CTAB was remarkably enhanced in the presence of trace level of atenolol. Under optimum experimental conditions, there is a linear relationship between the increase in CL intensity of KMnO4-CdS QDs-CTAB system and atenolol concentration in a range of 0.001 to 4.0 mg L(-1) and 4.0 to 18.0 mg L(-1), with a detection limit (3σ) of 0.0010 mg L(-1). A possible mechanism for KMnO4-CdS QDs-CTAB-atenolol CL reaction is proposed. To prove the practical application of the KMnO4-CdS QDs-CTAB CL method, the method was applied for the determination of atenolol in spiked environmental water samples and commercial pharmaceutical formulation. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) technique was utilized for determination of atenolol. Copyright © 2015 Elsevier B.V. All rights reserved.

Neuropathic pain and use of PainDETECT in patients with fibromyalgia: a cohort study.

PubMed

Gauffin, Jarno; Hankama, Tiina; Kautiainen, Hannu; Hannonen, Pekka; Haanpää, Maija

2013-02-14

Fibromyalgia has a plethorae of symptoms, which can be confusing and even misleading. Accurate evaluation is necessary when patients with fibromyalgia are treated. Different types of instruments are available for the clinicians to supplement evaluation. Our objective was to study the applicability of the PainDETECT instrument to screen neuropathic pain in patients with fibromyalgia. 158 patients with primary fibromyalgia underwent a neurological examination including bedside sensory testing. They also fulfilled four questionnaires: PainDETECT, Beck depression inventory IA (BDI IA), Fibromyalgia Impact Questionnaire (FIQ) and a self-made questionnaire regarding present pain and pain relieving methods of the patients. The results of the clinical evaluation and questionnaires were then compared. Clinically verified neuropathic pain was diagnosed in 53/158 [34% (95% Cl: 26 to 41)] patients. The ROC curve achieved a maximum Youden´s index at score of 17 when sensitivity was 0.79 (95% Cl: 0.66 to 0.89) and specificity 0.53 (95% Cl: 0.43 to 0.63). The PainDETECT total score (OR: 1.14 95% Cl: 1.06 to 1.22), FM as the worst current pain (OR: 0.31; 95% 0.16 to 0.62), body mass index (BMI) (OR: 1.05; 95% Cl: 1.00 to 1.11) and the intensity of current pain (OR: 1.20; 95% Cl: 1.01 to 1.41) were significantly associated with the presence of neuropathic pain in univariate analyses. This study highlights the importance of thorough clinical examination. The Neuropathic pain screening tool PainDETECT is not as useful in patients with fibromyalgia as in patients with uncompromised central pain control.

Red-emitting fluorescent probe for detecting hypochlorite acid in vitro and in vivo.

PubMed

Chen, Hong; Sun, Tao; Qiao, Xiao-Guang; Tang, Qian-Oian; Zhao, Shan-Chao; Zhou, Zhan

2018-06-12

Due to the importance of hypochlorous acid (HClO) in biological and industrial, development of fluorescent probes for HClO has been an active research area. Here, a new red-emitting ratiometric fluorescent probe (P) was synthesized and well defined characterization via NMR, HR-MS, and fluorescence spectrum, which serves as a selective and sensitive probe for ClO - group. The probe showed a ratiometric fluorescent response to hypochlorite at the emission intensities ratio (I 480 /I 612 ) increasing from 0.28 to 27.46. The emission intensities ratio (I 480 /I 612 ) was linearly enhanced (I 480 /I 612  = 0.064 X + 0.096) with the ClO - concentration range from 1 to 30 μM. The detection limitation for ClO - in aqueous solution is 0.47 μM. Moreover, this biocompatible red-emitting ratiometric fluorescent probe was utilized to the fluorescence imaging of ClO - in living cells and Zebrafish. Copyright © 2018. Published by Elsevier B.V.

Elucidating the Structure-Reactivity Correlations of Phenothiazine-Based Fluorescent Probes toward ClO.

PubMed

Wang, Shichao; Zhang, Boyu; Wang, Wenjing; Feng, Gang; Yuan, Daqiang; Zhang, Xuanjun

2018-06-07

In this work, with the aim of developing effective molecular probes and investigating the structure-reactivity correlation, a short series of phenothiazine-based fluorescent probes are designed for the detection of ClO - with differing electron push-pull groups. Sensing experiment results and single-crystal X-ray analysis with the aid of time-dependent DFT (TD-DFT) calculations reveal that substituting groups with increasing electron-withdrawing ability can increase the dihedral angle of the phenothiazine moiety and reduce the gap energy of the probes, leading to enhanced reactivity toward ClO - . Both PT1 and PT2 show two-color switching upon detection of ClO - . PT1, with the strong electron-donating group thiophene, shows a fluorescence color switch from salmon to blue. PT2, with a medium electron-donating/accepting group benzothiazole, shows a fluorescence color switch from red to green. However, both PT1 and PT2 show almost no response to ONOO - . Through the introduction of strong electron-withdrawing ketone combined with a cyano group, PT3 shows a cyan emission upon detection of ClO - and weak red emission upon detection of ONOO - . HRMS and 1 H NMR results confirm that PT1 and PT2 have the same sensing mode, in which the divalent sulfur of phenothiazine can be oxidized to sulfoxide by ClO - . Upon reaction with ClO - , PT3 experiences two-step reactions. It is first oxidized into the sulfone structure by ClO - , and then transformed into sulfoxide phenothiazine aldehyde. Upon encountering ONOO - , PT3 changes into an aldehyde structure and some nonfluorescent byproducts. Owing to their special selectivity and high sensitivity, PT1 and PT2 are applied to image the endogenous ClO - in macrophage cells and zebrafish larvae. This study is expected to provide useful guidelines for probe design for various applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franklin, C.C.

The effects of insulin on glucose transport and metabolism were examined in cultured HT29 human colonic adenocarcinoma cells. The presence of glucose transporters was verified by D-glucose displaceable ({sup 3}H) cytochalasin B binding. Moreover, two classes of insulin binding sites were detected in radioligand binding experiments. Despite the presence of both glucose transporters and insulin receptors, insulin failed to stimulate glucose transport. However, insulin was found to activate glycolysis. These findings suggest that insulin directly influences substrate utilization through the glycolytic pathway in HT29 cells without activating the glucose transport pathway. A Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport pathway was alsomore » detected in HT29 cells using {sup 86}Rb{sup +} as a K{sup +} congener. The identity of this pathway as a Na{sup +}/K{sup +}/Cl{sup {minus}} cotransporter has been deduced from the following findings: (1) {sup 86}Rb{sup +} influx was inhibited by loop diuretics, (2) {sup 86}Rb{sup +} influx ceased in the absence of any one of the transported ions, and (3) cotransport exhibited a stoichiometry approaching 1Na{sup +}:1K{sup +}:2Cl{sup {minus}}. Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport was found to be exquisitely sensitive to cellular ATP and cyclic AMP levels. These results suggest that HT29 cells contain a Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport pathway that can be regulated by the second messenger cyclic AMP and is highly sensitive to the metabolic state of the cell. The involvement of protein kinase C in the regulation of Na{sup +}/K{sup +}/Cl{sup {minus}} cotransport was also investigated. Phorbol 12-myristate 13-acetate (PMA), which stimulated protein kinase C activity, produced a transient increase in cotransport followed by a near abolition of cotransport by 2 h.« less

Application of a new chemiluminescence method for the determination of glucose-6-phosphate dehydrogenase activity in healthy and enzyme-deficient individuals.

PubMed

Gumuslu, Saadet; Yucel, Gultekin; Sarikcioglu, Sureyya Bilmen; Serteser, Mustafa

2005-01-01

A chemiluminescence (CL) technique, which determines the glucose-6-phosphate dehydrogenase (G-6-PD) activities in healthy, heterozygous, and completely enzyme-deficient individuals was applied. CL intensities were detected for 4 h at 15-min intervals in each sample with or without addition of G-6-PD substrates into the reaction mixture. The results revealed an inverse correlation to the reference UV method (Zinkham method; r=-0.80). Furthermore, the CL assay was able to detect G-6-PD activities as low as 0.2 IU/gHb, which was not possible by the UV method. In conclusion, we believe that this method offers a new diagnostic tool for the detection of G-6-PD activities in enzyme-deficient individuals and, because of its increased sensitivity, makes it amenable for determining the effects of different pharmaceutical agents on G-6-PD activity in tissue or cell cultures.

Chemiluminescence generation and detection in a capillary-driven microfluidic chip

NASA Astrophysics Data System (ADS)

Ramon, Charlotte; Temiz, Yuksel; Delamarche, Emmanuel

2017-02-01

The use of microfluidic technology represents a strong opportunity for providing sensitive, low-cost and rapid diagnosis at the point-of-care and such a technology might therefore support better, faster and more efficient diagnosis and treatment of patients at home and in healthcare settings both in developed and developing countries. In this work, we consider luminescence-based assays as an alternative to well-established fluorescence-based systems because luminescence does not require a light source or expensive optical components and is therefore a promising detection method for point-of-care applications. Here, we show a proof-of-concept of chemiluminescence (CL) generation and detection in a capillary-driven microfluidic chip for potential immunoassay applications. We employed a commercial acridan-based reaction, which is catalyzed by horseradish peroxidase (HRP). We investigated CL generation under flow conditions using a simplified immunoassay model where HRP is used instead of the complete sandwich immunocomplex. First, CL signals were generated in a capillary microfluidic chip by immobilizing HRP on a polydimethylsiloxane (PDMS) sealing layer using stencil deposition and flowing CL substrate through the hydrophilic channels. CL signals were detected using a compact (only 5×5×2.5 cm3) and custom-designed scanner, which was assembled for less than $30 and comprised a 128×1 photodiode array, a mini stepper motor, an Arduino microcontroller, and a 3D-printed housing. In addition, microfluidic chips having specific 30-μm-deep structures were fabricated and used to immobilize ensembles of 4.50 μm beads functionalized with HRP so as to generate high CL signals from capillary-driven chips.

Using signal amplification by reversible exchange (SABRE) to hyperpolarise 119Sn and 29Si NMR nuclei.

PubMed

Olaru, Alexandra M; Burt, Alister; Rayner, Peter J; Hart, Sam J; Whitwood, Adrian C; Green, Gary G R; Duckett, Simon B

2016-12-13

The hyperpolarisation of the 119 Sn and 29 Si nuclei in 5-(tributylstannyl)pyrimidine (A Sn ) and 5-(trimethylsilyl)pyrimidine (B Si ) is achieved through their reaction with [IrCl(COD)(IMes)] (1a) or [IrCl(COD)(SIMes)] (1b) and parahydrogen via the SABRE process. 1a exhibits superior activity in both cases. The two inequivalent pyrimidine proton environments of A Sn readily yielded signal enhancements totalling ∼2300-fold in its 1 H NMR spectrum at a field strength of 9.4 T, with the corresponding 119 Sn signal being 700 times stronger than normal. In contrast, B Si produced analogous 1 H signal gains of ∼2400-fold and a 29 Si signal that could be detected with a signal to noise ratio of 200 in a single scan. These sensitivity improvements allow NMR detection within seconds using micromole amounts of substrate and illustrate the analytical potential of this approach for high-sensitivity screening. Furthermore, after extended reaction times, a series of novel iridium trimers of general form [Ir(H) 2 Cl(NHC)(μ-pyrimidine-κN:κN')] 3 precipitate from these solutions whose identity was confirmed crystallographically for B Si .

Improved method for efficient imaging of intracellular Cl(-) with Cl-Sensor using conventional fluorescence setup.

PubMed

Friedel, Perrine; Bregestovski, Piotr; Medina, Igor

2013-01-01

Chloride (Cl(-)) homeostasis is known to be fundamental for central nervous system functioning. Alterations in intracellular Cl(-) concentration ([Cl(-)]i) and changes in the efficacy of Cl(-) extrusion are involved in numerous neurological disorders. Therefore, there is a strong need for studies of the dynamics of [Cl(-)]i in different cell types under physiological conditions and during pathology. Several previous works reported having successfully achieved recording of [Cl(-)]i using genetically encoded Cl-Sensor that is composed of the cyan fluorescent protein (CFP) and Cl(-)-sensitive mutant of the yellow fluorescent protein (YFPCl). However, all reported works were performed using specially designed setups with ultra-sensitive CCD cameras. Our multiple attempts to monitor Cl(-)-dependent fluorescence of Cl-Sensor using conventional epifluorescence microscopes did not yield successful results. In the present work, we have analysed the reason of our failures and found that they were caused by a strong inactivation of the YFPCl component of Cl-Sensor during excitation of the CFP with 430 nm light. Based on the obtained results, we reduced 20-fold the intensity of the 430 nm excitation and modified the recording protocol that allows now stable long-lasting ratiometric measurements of Cl-Sensor fluorescence in different cell types including cultured hippocampal neurons and their tiny dendrites and spines. Simultaneous imaging and patch clamp recording revealed that in mature neurons, the novel protocol allows detection of as little as 2 mM changes of [Cl(-)]i from the resting level of 5-10 mM. We demonstrate also a usefulness of the developed [Cl(-)]i measurement procedure for large scale screening of the activity of exogenously expressed potassium-chloride co-transporter KCC2, a major neuronal Cl(-) extruder that is implicated in numerous neurological disorders and is a target for novel therapeutical treatments.

Chemiluminescence immunoassay for the rapid and sensitive detection of antibody against porcine parvovirus by using horseradish peroxidase/detection antibody-coated gold nanoparticles as nanoprobes.

PubMed

Zhou, Yuan; Zhou, Tao; Zhou, Rui; Hu, Yonggang

2014-06-01

A rapid, simple, facile, sensitive and enzyme-amplified chemiluminescence immunoassay (CLIA) method to detect antibodies against porcine parvovirus has been developed. Horseradish peroxidase (HRP) and the detection antibody were simultaneously co-immobilized on the surface of gold nanoparticles using the electrostatic method to form gold nanoparticle-based nanoprobes. This nanoprobe was employed in a sandwich-type CLIA, which enables CL signal readout from enzymatic catalysis and results in signal amplification. The presence of porcine parvovirus infection was determined in porcine parvovirus antibodies by measuring the CL intensity caused by the reaction of HRP-luminol with H2 O2 . Under optimal conditions, the obtained calibration plot for the standard positive serum was approximately linear within the dilution range of 1:80 to 1:5120. The limit of detection for the assay was 1:10,240 (S/N = 3), which is much lower than that typically achieved with an enzyme-linked immunosorbent assay (1:160; S/N = 3). A series of repeatability measurements using 1:320-fold diluted standard positive serum gave reproducible results with a relative standard deviation of 4.9% (n = 11). The ability of the immunosensor to analyze clinical samples was tested on porcine sera. The immunosensor had an efficiency of 90%, a sensitivity of 93.3%, and a specificity of 87.5% relative to the enzyme-linked immunosorbent assay results. Copyright © 2013 John Wiley & Sons, Ltd.

Diagnostic Accuracy of Ascites Fluid Gross Appearance in Detection of Spontaneous Bacterial Peritonitis.

PubMed

Aminiahidashti, Hamed; Hosseininejad, Seyed Mohammad; Montazer, Hosein; Bozorgi, Farzad; Goli Khatir, Iraj; Jahanian, Fateme; Raee, Behnaz

2014-01-01

Spontaneous bacterial peritonitis (SBP) as a monomicrobial infection of ascites fluid is one of the most important causes of morbidity and mortality in cirrhotic patients. This study was aimed to determine the diagnostic accuracy of ascites fluid color in detection of SBP in cirrhotic cases referred to the emergency department. Cirrhotic patients referred to the ED for the paracentesis of ascites fluid were enrolled. For all studied patients, the results of laboratory analysis and gross appearance of ascites fluid registered and reviewed by two emergency medicine specialists. The sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ration of the ascites fluid gross appearance in detection of SBP were measured with 95% confidence interval. The present project was performed in 80 cirrhotic patients with ascites (52.5 female). The mean of the subjects' age was 56.25±12.21 years (35-81). Laboratory findings revealed SBP in 23 (29%) cases. Fifty nine (73%) cases had transparent ascites fluid appearance of whom 17 (29%) ones suffered from SBP. From 21 (26%) cases with opaque ascites appearance, 15 (71%) had SBP. The sensitivity and specificity of the ascites fluid appearance in detection of SBP were 46.88% (Cl: 30.87-63.55) and 87.50% (95% Cl: 75.3-94.14), respectively. It seems that the gross appearance of ascites fluid had poor diagnostic accuracy in detection of SBP and considering its low sensitivity, it could not be used as a good screening tool for this propose.

Uptake of hexanitrohexaazaisowurtzitane (CL-20) by the earthworm Eisenia fetida through dermal contact.

PubMed

Gong, Ping; Escalon, B Lynn; Hayes, Charolett A; Perkins, Edward J

2008-02-01

The explosive compound hexanitrohexaazaisowurtzitane (CL-20) has been shown to cause both lethal and sublethal (reproductive and neurotoxic) effects in exposed oligochaetes. However, whether worms take up CL-20 and how much CL-20 enters worm bodies leading to toxicity (e.g., lethality) remain to be determined. In the present study, we used high performance liquid chromatography (HPLC) and radiolabeled tracer methods to investigate the CL-20 uptake in the whole worm body after contact exposures. Worms (Eisenia fetida) were exposed to filter paper spiked with non-radioactive or [U-(14)C]-labeled CL-20 for 1-3 d. The radiolabeled tracer method allowed us to detect the parent compound and transformation products in worms exposed to as low as 0.04 microg CL-20 cm(-2) of filter paper. The HPLC method without radiolabeled tracer was far less sensitive with a detection limit of 2.17 microg CL-20 cm(-2). Using the radiolabeled tracer, we were able to demonstrate that the worm body concentration linearly correlated to the filter paper concentration < or =0.34 microg cm(-2) (r=0.94) if no breakdown products are assumed. At higher concentrations, the body concentration increased slowly and saturated at around 11 microg g(-1) dry mass resulting in an estimated lethal critical body burden of 10-15 microg CL-20 g(-1) dry mass. These findings demonstrate that CL-20 or potential transformation products are taken into the earthworm body through dermal contact. This information should prove valuable in assessing the bioaccumulation potential and ecological risks of CL-20.

Development of a rapid loop-mediated isothermal amplification assay for diagnosis and assessment of cure of Leishmania infection.

PubMed

Verma, Sandeep; Singh, Ruchi; Sharma, Vanila; Bumb, Ram Avtar; Negi, Narendra Singh; Ramesh, V; Salotra, Poonam

2017-03-23

Leishmaniasis is a spectrum of diseases with great relevance to public health. Conventional diagnostic methods are time consuming, needing trained personnel. A robust, rapid and cost effective diagnostic test is warranted for on-time diagnosis and field application. We have developed a loop mediated isothermal amplification (LAMP) assay with primers (n = 6) based on Leishmania donovani kDNA for detection of Leishmania infection, using a closed tube to prevent cross-contamination. The assay was used to detect Leishmania infection in biological samples obtained from patients of visceral leishmaniasis (VL), post kala-azar dermal leishmaniasis (PKDL) and cutaneous leishmaniasis (CL). The assay was positive for L. donovani, L. tropica and L. major parasites, with the highest sensitivity towards L. donovani (1 fg DNA). The high sensitivity of the assay for detection of L. donovani was reflected in its ability to detect parasite DNA within 30 min of amplification time with a threshold detection limit of ≥25 copies per reaction. The assay detected parasite in 64 of 66 VL blood samples (sensitivity, 96.9%; 95% CI: 89.6-99.2%), 15 of 15 VL bone marrow aspirate samples (sensitivity, 100%; 95% CI:79.6-100%), 65 of 67 PKDL tissue biopsy samples (sensitivity, 97%; 95% CI:89.7-99.2%). The assay was evaluated in a few cases of CL wherein it was found positive in 8 of 10 tissue biopsies (sensitivity, 80%; 95% CI: 49-94.3%). The assay was negative in all control blood (n = 76) and tissue biopsy (n = 24) samples (specificity, 100%; 95% CI: 96.3-100%). Further, the assay was evaluated for its utility in assessment of cure in treated VL and PKDL patients. The assay detected parasite DNA in 2 of 20VL blood samples and 2 of 21 PKDL tissue samples. Out of 4 cases that were positive for parasite DNA at post treatment stage, 2 patients (1VL and 1 PKDL) returned with relapse. The study demonstrated a Leishmania genus specific closed tube LAMP assay for reliable and rapid molecular diagnosis of VL and PKDL with potential for application in assessment of cure.

A novel coumarin-pyrazole-triazine based fluorescence chemosensor for fluoride detection via deprotonation process: Experimental and theoretical studies

NASA Astrophysics Data System (ADS)

Yalçın, Ergin; Alkış, Meltem; Seferoğlu, Nurgül; Seferoğlu, Zeynel

2018-03-01

A novel fluorescence coumarin-pyrazole-triazine based chemosensor (CPT) bearing 5-hydroxypyrazole as a receptoric part was synthesized and characterized by using IR, 1H/13C NMR and HRMS for the purpose of recognition of anions in DMSO. The most stable tautomeric form of CPT was determined by experimental techniques and theoretical calculations. The selectivity and sensitivity of CPT towards anions (CN-, F-, Cl-, Br-, I-, AcO-, HSO4-, H2PO4- and ClO4-) were determined using spectrophotometric and 1H NMR titration techniques as the experimental approach, and the results were explained by employing theoretical calculations. It was found to be suitable for the selective detection of F- in the presence of CN- and AcO- as competing anions. In addition, CPT exhibits significant "light-up" effect after interaction with TFA in CH2Cl2.

Characterization of glial cell K-Cl cotransport.

PubMed

Gagnon, Kenneth B E; Adragna, Norma C; Fyffe, Robert E W; Lauf, Peter K

2007-01-01

The molecular mechanism of K-Cl cotransport (KCC) consists of at least 4 isoforms, KCC 1, 2, 3, and 4 which, in multiple combinations, exist in most cells, including erythrocytes and neuronal cells. We utilized reverse-transcriptase-polymerase chain reaction (RT-PCR) and ion flux studies to characterize KCC activity in an immortalized in vitro cell model for fibrous astrocytes, the rat C6 glioblastoma cell. Isoform-specific sets of oligonucleotide primers were synthesized for NKCC1, KCC1, KCC2, KCC3, KCC4, and also for NKCC1 and actin. K-Cl cotransport activity was determined by measuring either the furosemide-sensitive, or the Cl(-)-dependent bumetanide-insensitive Rb(+) (a K(+) congener) influx in the presence of the Na/K pump inhibitor ouabain. Rb(+) influx was measured at a fixed external Cl concentrations, [Cl(-)](e), as a function of varying external Rb concentrations, [Rb(+)](e), and at a fixed [Rb(+)](e) as a function of varying [Cl(-)](e), and with equimolar Cl replacement by anions of the chaotropic series. RT-PCR of C6 glioblastoma (C6) cells identified mRNA for three KCC isoforms (1, 3, and 4). NKCC1 mRNA was also detected. The apparent K(m) for KCC-mediated Rb(+) influx was 15 mM [Rb(+)](e), and V(max) 12.5 nmol Rb(+) * mg protein(-1) * minute(-1). The calculated apparent K(m) for external Cl(-) was 13 mM and V(max) 14.4 nmol Rb(+) * mg protein(-1) * minute(-1). The anion selectivity sequence of the furosemide-sensitive Rb(+) influx was Cl(-)>Br-=NO(3)(-)>I(-)=SCN(-)>Sfm(-) (sulfamate). Established activators of K-Cl cotransport, hyposmotic shock and N-ethylmaleimide (NEM) pretreatment, stimulated furosemide-sensitive Rb(+) influx. A ñ50% NEM-induced loss of intracellular K(+) was prevented by furosemide. We have identified by RT-PCR the presence of three distinct KCC isoforms (1, 3, and 4) in rat C6 glioblastoma cells, and functionally characterized the anion selectivity and kinetics of their collective sodium-independent cation-chloride cotransport activity.

Effects of cations and anions as aggregating agents on SERS detection of cotinine (COT) and trans-3'-hydroxycotinine (3HC).

PubMed

Han, Sungyub; Hong, Seongmin; Li, Xiao

2013-11-15

The sensitivity of surface-enhanced Raman spectroscopy (SERS) highly depends on experimental factors including aggregating agents and pH. Using silver nanoparticles as the substrate, the effect of five cationic (K(+), Na(+), Mg(2+), Li(+), Ca(2+)) and three anionic (Cl(-), Br(-), I(-)) aggregating agents was examined on the SERS detection of tobacco-related biomarkers, namely cotinine (COT) and trans-3'-hydroxycotinine (3HC). The optimal concentrations of the aggregating agents with respect to highest SERS intensity varied widely (from 1.5 mM for MgCl2 to 150 mM for LiCl). Both cations and anions strongly influenced the SERS enhancement. When Cl(-) was used as the anion, Mg(2+) and Na(+) exhibited the highest SERS intensities for COT and 3HC, respectively. When Mg(2+) was used as the cation, Cl(-) and Br(-) generated the highest SERS enhancement for COT and 3HC, respectively. Clearly, SERS enhancement also depended on the target molecule. Among the 11 aggregating agent combinations tested, the highest SERS enhancement is obtained using 1.5 mM MgCl2 for COT at pH 7.0 and 50 mM NaBr for 3HC at pH 3.0. Copyright © 2013 Elsevier Inc. All rights reserved.

An easy prepared dual-channel chemosensor for selective and instant detection of fluoride based on double Schiff-base

NASA Astrophysics Data System (ADS)

Leng, Yan-Li; Zhang, Jian-Hui; Li, Qiao; Zhang, You-Ming; Lin, Qi; Yao, Hong; Wei, Tai-Bao

2016-10-01

A colorimetric and fluorescent dual-channel fluoride chemosensor N,N‧-bis (4-diethylaminosalicylidene) hydrazine (sensor S) bearing two imine groups has been designed and synthesized. This structurally simple probe displays rapid response and high selectivity for fluoride over other common anions (Cl-, Br-, I-, AcO-, H2PO4-, HSO4-, ClO4-, CN- and SCN-) in a highly polar aqueous DMSO solution. Mechanism studies suggested that the sensor firstly combined with F- through hydrogen bonds and then experienced the deprotonation process at higher concentrations of F- anion to the two Ar-OH groups. The detection limit was 5.78 × 10- 7 M of F-, which points to the high detection sensitivity. Test strips based on sensor S were fabricated, which could act as a convenient and efficient F- test kit to detect F- for ;in-the-field; measurement.

Field detection capability of immunochemical assays during criminal investigations involving the use of TNT.

PubMed

Romolo, Francesco Saverio; Ferri, Elida; Mirasoli, Mara; D'Elia, Marcello; Ripani, Luigi; Peluso, Giuseppe; Risoluti, Roberta; Maiolini, Elisabetta; Girotti, Stefano

2015-01-01

The capability to collect timely information about the substances employed on-site at a crime scene is of fundamental importance during scientific investigations in crimes involving the use of explosives. TNT (2,4,6-trinitrotoluene) is one of the most employed explosives in the 20th century. Despite the growing use of improvised explosives, criminal use and access to TNT is not expected to decrease. Immunoassays are simple and selective analytical tests able to detect molecules and their immunoreactions can occur in portable formats for use on-site. This work demonstrates the application of three immunochemical assays capable of detecting TNT to typical forensic samples from experimental tests: an indirect competitive ELISA with chemiluminescent detection (CL-ELISA), a colorimetric lateral flow immunoassay (LFIA) based on colloidal gold nanoparticles label, and a chemiluminescent-LFIA (CL-LFIA). Under optimised working conditions, the LOD of the colorimetric LFIA and CL-LFIA were 1 μg mL(-1) and 0.05 μg mL(-1), respectively. The total analysis time for LFIAs was 15 min. ELISA proved to be a very effective laboratory approach, showing very good sensitivity (LOD of 0.4 ng mL(-1)) and good reproducibility (CV value about 7%). Samples tested included various materials involved in controlled explosions of improvised explosive devices (IEDs), as well as hand swabs collected after TNT handling tests. In the first group of tests, targets covered with six different materials (metal, plastic, cardboard, carpet fabric, wood and adhesive tape) were fixed on top of wooden poles (180 cm high). Samples of soil from the explosion area and different materials covering the targets were collected after each explosion and analysed. In the second group of tests, hand swabs were collected with and without hand washing after volunteers simulated the manipulation of small charges of TNT. The small amount of solution required for each assay allows for several analyses. Results of immunoassays confirmed that they were suitable to detect post-blast residues in soil and target materials and post transfer residues on hands, allowing further confirmation by more selective techniques. ELISA and LFIAs results obtained from the same solution were consistently in good agreement, and were confirmed by gas chromatography coupled to mass spectrometry (GC-MS). The reported immunoassays data demonstrates the suitability of LFIAs as on-site rapid and effective assays to detect TNT traces. The CL-ELISA proved useful in obtaining very sensitive detection in forensic investigations and testing, while CL-LFIA had performances in between LFIA and CL-ELISA. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Determination of bromine, chlorine and iodine in environmental aqueous samples by epithermal neutron activation analysis and Compton suppression

USGS Publications Warehouse

Landsberger, S.; O'Kelly, D. J.; Braisted, J.; Panno, S.

2006-01-01

Halides, particularly Br- and Cl-, have been used as indicators of potential sources of Na+ and Cl- in surface water and groundwater with limited success. Contamination of groundwater and surface water by Na+ and Cl- is a common occurrence in growing urban areas and adversely affects municipal and private water supplies in Illinois and other states, as well as vegetation in environmentally sensitive areas. Neutron activation analysis (NAA) can be effectively used to determine these halogens, but often the elevated concentrations of sodium and chlorine in water samples can give rise to very high detection limits for bromine and iodine due to elevated backgrounds from the activation process. We present a detailed analytical scheme to determine Cl, Br and I in aqueous samples with widely varying Na and Cl concentrations using epithermal NAA in conjunction with Compton suppression. ?? 2006 Akade??miai Kiado??.

Measurement of hydroxyl radical production in ultrasonic aqueous solutions by a novel chemiluminescence method.

PubMed

Hu, Yufei; Zhang, Zhujun; Yang, Chunyan

2008-07-01

Measurement methods for ultrasonic fields are important for reasons of safety. The investigation of an ultrasonic field can be performed by detecting the yield of hydroxyl radicals resulting from ultrasonic cavitations. In this paper, a novel method is introduced for detecting hydroxyl radicals by a chemiluminescence (CL) reaction of luminol-hydrogen peroxide (H2O2)-K5[Cu(HIO6)2](DPC). The yield of hydroxyl radicals is calculated directly by the relative CL intensity according to the corresponding concentration of H2O2. This proposed CL method makes it possible to perform an in-line and real-time assay of hydroxyl radicals in an ultrasonic aqueous solution. With flow injection (FI) technology, this novel CL reaction is sensitive enough to detect ultra trace amounts of H2O2 with a limit of detection (3sigma) of 4.1 x 10(-11) mol L(-1). The influences of ultrasonic output power and ultrasonic treatment time on the yield of hydroxyl radicals by an ultrasound generator were also studied. The results indicate that the amount of hydroxyl radicals increases with the increase of ultrasonic output power (< or = 15 W mL(-1)). There is a linear relationship between the time of ultrasonic treatment and the yield of H2O2. The ultrasonic field of an ultrasonic cleaning baths has been measured by calculating the yield of hydroxyl radicals.

Study of catalytic reaction processes on the {gamma}-Al{sub 2}O{sub 3} chemiluminescence-based gas sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Utsunomiya, K.; Nakagawa, M.; Nishiyama, K.

The authors have investigated a new chemiluminescence (CL)-based gas sensor made of aluminum oxide ({gamma}-Al{sub 2}O{sub 3}) which emits CL during the catalytic oxidation of combustible vapors in air. The CL intensity is proportional to the concentration in the wide region from 1 to 1000 ppm of ethanol, butanol and acetone in air. However, it has a tendency to saturate in concentrations above 1000 ppm. For the detection of vapors in the environmental atmosphere, improvements of the sensitivity and the linear characteristics of the sensor are necessary. Catalytic reaction processes on the sensor were studied for this purpose.

Enhanced chemiluminescence of carminic acid-permanganate by CdS quantum dots and its application for sensitive quenchometric flow injection assays of cloxacillin.

PubMed

Khataee, Alireza; Hasanzadeh, Aliyeh; Lotfi, Roya; Joo, Sang Woo

2016-05-15

A novel chemiluminescence (CL) system is introduced based on the oxidation of carminic acid by KMnO4 in acidic conditions. CdS quantum dots (QDs) were synthesized using a facile hydrothermal method which efficiently enhanced the intensity of the CL system. A possible mechanism for the proposed system is presented using the kinetic curves, CL spectra, photoluminescence (PL), and ultraviolet-visible (UV-Vis) analysis. The emission intensity of the KMnO4-carminic acid-CdS QDs system was quenched in the presence of a trace level of cloxacillin. Based on this quenching effect, a novel and sensitive flow injection CL method was developed for determining cloxacillin concentrations. At optimal experimental conditions, the decreased CL intensity had a good linear relation with the cloxacillin concentration in the range of 0.008 to 22.0 mg L(-1). The detection limit (3σ) was 5.8 µg L(-1). The precision of the method was calculated by analyzing samples containing 4.0 mg L(-1) of cloxacillin (n=11), and the relative standard deviations (RSD%) were 2.08%. The feasibility of the method is also demonstrated for determining cloxacillin concentrations in environmental water samples and a pharmaceutical formulation. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparative assessment of cardiac activity and DNA damage in haemocytes of the Mediterranean mussel Mytilus galloprovincialis in exposure to tributyltin chloride.

PubMed

Martinović, Rajko; Kolarević, Stoimir; Kračun-Kolarević, Margareta; Kostić, Jovana; Jokanović, Sandra; Gačić, Zoran; Joksimović, Danijela; Đurović, Mirko; Kljajić, Zoran; Vuković-Gačić, Branka

2016-10-01

This study gives an insight in sensitivity of heart rate (Hr) of Mytilus galloprovincialis as a physiological biomarker. Impact of tributyltin chloride (TBT-Cl) on Hr was studied in parallel with evaluation of mutagenic, genotoxic and cytotoxic potential of TBT-Cl (10, 100 and 1000μg/L) within 96h treatment in static conditions. Mutagenic potential was assessed by SOS/umuC assay while genotoxicity was assessed in haemocytes of M. galloprovincialis by using the comet assay and the micronucleus test. Benzo(a)pyrene (B(a)P) was used as a positive control. Hr variations detected in TBT-Cl treatments can be linked to data obtained in the genotoxicological assays indicating that Hr can be considered and used as a reliable physiological biomarker for detecting the presence of organotin compounds. However despite the observed genotoxic potential of B(a)P, a noteworthy Hr response was not observed which further questions the potential of Hr in the detection of different types of pollutants. Copyright © 2016 Elsevier B.V. All rights reserved.

Diagnostic Accuracy of Ascites Fluid Gross Appearance in Detection of Spontaneous Bacterial Peritonitis

PubMed Central

Aminiahidashti, Hamed; Hosseininejad, Seyed Mohammad; Montazer, Hosein; Bozorgi, Farzad; Goli Khatir, Iraj; Jahanian, Fateme; Raee, Behnaz

2014-01-01

Introduction: Spontaneous bacterial peritonitis (SBP) as a monomicrobial infection of ascites fluid is one of the most important causes of morbidity and mortality in cirrhotic patients. This study was aimed to determine the diagnostic accuracy of ascites fluid color in detection of SBP in cirrhotic cases referred to the emergency department. Methods: Cirrhotic patients referred to the ED for the paracentesis of ascites fluid were enrolled. For all studied patients, the results of laboratory analysis and gross appearance of ascites fluid registered and reviewed by two emergency medicine specialists. The sensitivity, specificity, positive and negative predictive value, and positive and negative likelihood ration of the ascites fluid gross appearance in detection of SBP were measured with 95% confidence interval. Results: The present project was performed in 80 cirrhotic patients with ascites (52.5 female). The mean of the subjects’ age was 56.25±12.21 years (35-81). Laboratory findings revealed SBP in 23 (29%) cases. Fifty nine (73%) cases had transparent ascites fluid appearance of whom 17 (29%) ones suffered from SBP. From 21 (26%) cases with opaque ascites appearance, 15 (71%) had SBP. The sensitivity and specificity of the ascites fluid appearance in detection of SBP were 46.88% (Cl: 30.87-63.55) and 87.50% (95% Cl: 75.3-94.14), respectively. Conclusion: It seems that the gross appearance of ascites fluid had poor diagnostic accuracy in detection of SBP and considering its low sensitivity, it could not be used as a good screening tool for this propose. PMID:26495366

Assay of picogram level isocarbophos residue on tangerines and oranges with luminol-albumin chemiluminescence system.

PubMed

Chen, Donghua; Song, Zhenghua; Lv, Hairu

2012-12-15

A sensitive flow injection-chemiluminescence (FI-CL) method for the determination of isocarbophos (ICP) residue on tangerines and oranges was proposed. It was found that the CL intensity from luminol-albumin CL reaction could be obviously quenched in the presence of ICP and the decrease in CL intensity was proportional to the logarithm of ICP concentrations ranging from 1.0 to 1000 pmol L(-1), giving the limit of detection of 0.3 pmol L(-1) (3σ). The proposed procedure was successfully applied to the determination of ICP residue on tangerines and oranges with recoveries varying from 92.0 to 111.0% and RSDs less than 5.0%. The possible CL mechanism of luminol-albumin-ICP reaction was discussed, and ICP to albumin's binding constant (K(D)=1.00 × 10(6) L mol(-1)) and the number of binding sites (n=1.00) were given by the homemade FI-CL model. Copyright © 2012 Elsevier Ltd. All rights reserved.

Pre-evaluation of metal ions as a catalyst on chemiluminometric sequential injection analysis with luminol-H2O2 system.

PubMed

Takayanagi, Toshio; Inaba, Yuya; Kanzaki, Hiroyuki; Jyoichi, Yasutaka; Motomizu, Shoji

2009-09-15

Catalytic effect of metal ions on luminol chemiluminescence (CL) was investigated by sequential injection analysis (SIA). The SIA system was set up with two solenoid micropumps, an eight-port selection valve, and a photosensor module with a fountain-type chemiluminescence cell. The SIA system was controlled and the CL signals were collected by a LabVIEW program. Aqueous solutions of luminol, H(2)O(2), and a sample solution containing metal ion were sequentially aspirated to the holding coil, and the zones were immediately propelled to the detection cell. After optimizing the parameters using 1 x 10(-5)M Fe(3+) solution, catalytic effect of some metal species was compared. Among 16 metal species examined, relatively strong CL responses were obtained with Fe(3+), Fe(2+), VO(2+), VO(3)(-), MnO(4)(-), Co(2+), and Cu(2+). The limits of detection by the present SIA system were comparable to FIA systems. Permanganate ion showed the highest CL sensitivity among the metal species examined; the calibration graph for MnO(4)(-) was linear at the concentration level of 10(-8)M and the limit of detection for MnO(4)(-) was 4.0 x 10(-10)M (S/N=3).

Colorimetric and luminescent bifunctional iridium(III) complexes for the sensitive recognition of cyanide ions

NASA Astrophysics Data System (ADS)

Chen, Xiudan; Wang, Huili; Li, Jing; Hu, Wenqin; Li, Mei-Jin

2017-02-01

Two new cyclometalated iridium(III) complexes [(ppy)2Irppz]Cl (1) and [(ppy)2Irbppz]Cl (2) (where ppy = 2-phenylpyridine, ppz = 4,7-phenanthrolino-5,6:5,6-pyrazine, bppz = 2.3-di-2-pyridylpyrazine), were designed and synthesized. The structure of [(ppy)2Irppz]Cl was determined by single crystal X-ray diffraction. Their photophysical properties were also studied. This kind of complexes could coordinate with Cu2 +, the photoluminescence (PL) of the complex was quenched, and the color changed from orange-red to green. The forming M-Cu (M: complexes 1 and 2) ensemble could be further utilized as a colorimetric and emission ;turn-on; bifunctional detection for CN-, especially for complex 1-Cu2 + showed a high sensitivity toward CN- with a limit of diction is 97 nM. Importantly, this kind of iridium(III) complexes shows a unique recognition of cyanide ions over other anions which makes it an eligible sensing probe for cyanide ions.

Highly sensitive chemiluminescence immunoassay on chitosan membrane modified paper platform using TiO2 nanoparticles/multiwalled carbon nanotubes as label.

PubMed

Li, Weiping; Ge, Shenguang; Wang, Shoumei; Yan, Mei; Ge, Lei; Yu, Jinghua

2013-01-01

A highly sensitive chemiluminescence (CL) immunoassay was incorporated into a low-cost microfluidic paper-based analytical device (μ-PAD) to fabricate a facile paper-based CL immunodevice (denoted as μ-PCLI). This μ-PCLI was constructed by covalently immobilizing capture antibody on a chitosan membrane modified μ-PADs, which was developed by simple wax printing methodology. TiO2 nanoparticles coated multiwalled carbon nanotubes (TiO2/MWCNTs) were synthesized as an amplification catalyst tag to label signal antibody (Ab2). After sandwich-type immunoreactions, the TiO2/MWCNTs were captured on the surface of μ-PADs to catalyze the luminol-p-iodophenol-H2O2 CL system, which produced an enhanced CL emission. Using prostate-specific antigen as a model analyte, the approach provided a good linear response range from 0.001 to 20 ng/mL with a low detection limit of 0.8 pg/mL under optimal conditions. This μ-PCLI showed good reproducibility, selectivity and stability. The assay results of prostate-specific antigen in clinical serum samples were in good agreement with that obtained by commercially used electrochemiluminescence methods at the Cancer Research Center of Shandong Tumor Hospital (Jinan, Shandong Province, China). This μ-PCLI could be very useful to realize highly sensitive, qualitative point-of-care testing in developing or developed countries. Copyright © 2013 John Wiley & Sons, Ltd.

Quantification of MDMA and MDA in abusers' hair samples by semi-micro column HPLC with fluorescence detection.

PubMed

Nakamura, Shinichi; Tomita, Mamoru; Wada, Mitsuhiro; Chung, Heesun; Kuroda, Naotaka; Nakashima, Kenichiro

2006-01-01

A sensitive semi-micro column high-performance liquid chromatography with fluorescence detection method was developed for the determination of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA), methamphetamine (MP) and amphetamine (AP) in human hair. 4-(4,5-Diphenyl-1H-imidazol-2-yl)benzoyl chloride (DIB-Cl) and 1-methyl-3-phenylpropylamine were used as labeling reagent and internal standard, respectively. These drugs were extracted from hair into 5% trifluoroacetic acid in methanol, and fluorescent labeled with DIB-Cl. The separation of DIB-derivatives was achieved on a reversed-phase semi-micro ODS column with an acetonitrile-methanol-water (30:40:30, v/v/v%) mixture as a mobile phase. The limits of detection at a signal-to-noise ratio of 3 for MDMA, MDA, MP and AP were 0.25, 0.15, 0.25 and 0.19 ng/mg, respectively. Precision of intra- and inter-day assay as the relative standard deviation were in the range 1.5-6.8% (n = 5) and 2.7-4.7% (n = 5), respectively. The proposed method was highly sensitive and able to detect MDMA and its related compounds in small amounts of hair sample, and could be applied to quantification of six abusers' hair samples. Copyright 2006 John Wiley & Sons, Ltd.

Salty taste deficits in CALHM1 knockout mice.

PubMed

Tordoff, Michael G; Ellis, Hillary T; Aleman, Tiffany R; Downing, Arnelle; Marambaud, Philippe; Foskett, J Kevin; Dana, Rachel M; McCaughey, Stuart A

2014-07-01

Genetic ablation of calcium homeostasis modulator 1 (CALHM1), which releases adenosine triphosphate from Type 2 taste cells, severely compromises the behavioral and electrophysiological responses to tastes detected by G protein-coupled receptors, such as sweet and bitter. However, the contribution of CALHM1 to salty taste perception is less clear. Here, we evaluated several salty taste-related phenotypes of CALHM1 knockout (KO) mice and their wild-type (WT) controls: 1) In a conditioned aversion test, CALHM1 WT and KO mice had similar NaCl avoidance thresholds. 2) In two-bottle choice tests, CALHM1 WT mice showed the classic inverted U-shaped NaCl concentration-preference function but CALHM1 KO mice had a blunted peak response. 3) In brief-access tests, CALHM1 KO mice showed less avoidance than did WT mice of high concentrations of NaCl, KCl, NH(4)Cl, and sodium lactate (NaLac). Amiloride further ameliorated the NaCl avoidance of CALHM1 KO mice, so that lick rates to a mixture of 1000 mM NaCl + 10 µM amiloride were statistically indistinguishable from those to water. 4) Relative to WT mice, CALHM1 KO mice had reduced chorda tympani nerve activity elicited by oral application of NaCl, NaLac, and sucrose but normal responses to HCl and NH(4)Cl. Chorda tympani responses to NaCl and NaLac were amiloride sensitive in WT but not KO mice. These results reinforce others demonstrating that multiple transduction pathways make complex, concentration-dependent contributions to salty taste perception. One of these pathways depends on CALHM1 to detect hypertonic NaCl in the mouth and signal the aversive taste of concentrated salt. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Salty Taste Deficits in CALHM1 Knockout Mice

PubMed Central

Ellis, Hillary T.; Aleman, Tiffany R.; Downing, Arnelle; Marambaud, Philippe; Foskett, J. Kevin; Dana, Rachel M.; McCaughey, Stuart A.

2014-01-01

Genetic ablation of calcium homeostasis modulator 1 (CALHM1), which releases adenosine triphosphate from Type 2 taste cells, severely compromises the behavioral and electrophysiological responses to tastes detected by G protein–coupled receptors, such as sweet and bitter. However, the contribution of CALHM1 to salty taste perception is less clear. Here, we evaluated several salty taste–related phenotypes of CALHM1 knockout (KO) mice and their wild-type (WT) controls: 1) In a conditioned aversion test, CALHM1 WT and KO mice had similar NaCl avoidance thresholds. 2) In two-bottle choice tests, CALHM1 WT mice showed the classic inverted U-shaped NaCl concentration-preference function but CALHM1 KO mice had a blunted peak response. 3) In brief-access tests, CALHM1 KO mice showed less avoidance than did WT mice of high concentrations of NaCl, KCl, NH4Cl, and sodium lactate (NaLac). Amiloride further ameliorated the NaCl avoidance of CALHM1 KO mice, so that lick rates to a mixture of 1000mM NaCl + 10 µM amiloride were statistically indistinguishable from those to water. 4) Relative to WT mice, CALHM1 KO mice had reduced chorda tympani nerve activity elicited by oral application of NaCl, NaLac, and sucrose but normal responses to HCl and NH4Cl. Chorda tympani responses to NaCl and NaLac were amiloride sensitive in WT but not KO mice. These results reinforce others demonstrating that multiple transduction pathways make complex, concentration-dependent contributions to salty taste perception. One of these pathways depends on CALHM1 to detect hypertonic NaCl in the mouth and signal the aversive taste of concentrated salt. PMID:24846212

The Use of Flow-Injection Analysis with Chemiluminescence Detection of Aqueous Ferrous Iron in Waters Containing High Concentrations of Organic Compounds

PubMed Central

Borman, Christopher J.; Sullivan, B. Patrick; Eggleston, Carrick M.; Colberg, Patricia J. S.

2009-01-01

An evaluation of flow-injection analysis with chemiluminescence detection (FIA-CL) to quantify Fe2+(aq) in freshwaters was performed. Iron-coordinating and/or iron-reducing compounds, dissolved organic matter (DOM), and samples from two natural water systems were used to amend standard solutions of Fe2+(aq). Slopes of the response curves from ferrous iron standards (1 – 100 nM) were compared to the response curves of iron standards containing the amendments. Results suggest that FIA-CL is not suitable for systems containing ascorbate, hydroxylamine, cysteine or DOM. Little or no change in sensitivity occurred in solutions of oxalate and glycine or in natural waters with little organic matter. PMID:22408532

Peroxyoxalate chemiluminescence detection for the highly sensitive determination of fluorescence-labeled chlorpheniramine with Suzuki coupling reaction.

PubMed

Adutwum, Lawrence Asamoah; Kishikawa, Naoya; Ohyama, Kaname; Harada, Shiro; Nakashima, Kenichiro; Kuroda, Naotaka

2010-09-01

A sensitive and selective high performance liquid chromatography-peroxyoxalate chemiluminescence (PO-CL) method has been developed for the simultaneous determination of chlorpheniramine (CPA) and monodesmethyl chlorpheniramine (MDCPA) in human serum. The method combines fluorescent labeling with 4-(4,5-diphenyl-1H-imidazole-2-yl)phenyl boronic acid using Suzuki coupling reaction with PO-CL detection. CPA and MDCPA were extracted from human serum by liquid-liquid extraction with n-hexane. Excess labeling reagent, which interfered with trace level determination of analytes, was removed by solid-phase extraction using a C18 cartridge. Separation of derivatives of both analytes was achieved isocratically on a silica column with a mixture of acetonitrile and 60 mM imidazole-HNO(3) buffer (pH 7.2; 85:15, v/v) containing 0.015% triethylamine. The proposed method exhibited a good linearity with a correlation coefficient of 0.999 for CPA and MDCPA within the concentration range of 0.5-100 ng/mL. The limits of detection (S/N = 3) were 0.14 and 0.16 ng/mL for CPA and MDCPA, respectively. Using the proposed method, CPA could be selectively determined in human serum after oral administration.

Carbon nanopipette electrodes for dopamine detection in Drosophila.

PubMed

Rees, Hillary R; Anderson, Sean E; Privman, Eve; Bau, Haim H; Venton, B Jill

2015-04-07

Small, robust, sensitive electrodes are desired for in vivo neurotransmitter measurements. Carbon nanopipettes have been previously manufactured and used for single-cell drug delivery and electrophysiological measurements. Here, a modified fabrication procedure was developed to produce batches of solid carbon nanopipette electrodes (CNPEs) with ∼250 nm diameter tips, and controllable lengths of exposed carbon, ranging from 5 to 175 μm. The electrochemical properties of CNPEs were characterized with fast-scan cyclic voltammetry (FSCV) for the first time. CNPEs were used to detect the electroactive neurotransmitters dopamine, serotonin, and octopamine. CNPEs were significantly more sensitive for serotonin detection than traditional carbon-fiber microelectrodes (CFMEs). Similar to CFMEs, CNPEs have a linear response for dopamine concentrations ranging from 0.1 to 10 μM and a limit of detection of 25 ± 5 nM. Recordings with CNPEs were stable for over 3 h when the applied triangle waveform was scanned between -0.4 and +1.3 V vs Ag/AgCl/Cl(-) at 400 V/s. CNPEs were used to detect endogenous dopamine release in Drosophila larvae using optogenetics, which verified the utility of CNPEs for in vivo neuroscience studies. CNPEs are advantageous because they are 1 order of magnitude smaller in diameter than typical CFMEs and have a sharp, tunable geometry that facilitates penetration and implantation for localized measurements in distinct regions of small organisms, such as the Drosophila brain.

Direct detection of Leishmania from clinical samples.

PubMed

Waitumbi, John N; Bast, Joshua; Nyakoe, Nancy; Magiri, Charles; Quintana, Miguel; Takhampunya, Ratree; Schuster, Anthony L; Van de Wyngaerde, Marshall T; McAvin, James C; Coleman, Russell E

2017-01-01

The ability to rapidly and accurately diagnose leishmaniasis is a military priority. Testing was conducted to evaluate diagnostic sensitivity and specificity of field-expedient Leishmania genus and visceral Leishmania specific dual-fluorogenic, hydrolysis probe (TaqMan), polymerase chain reaction assays previously established for use in vector surveillance. Blood samples of patients with confirmed visceral leishmaniasis and controls without the disease from Baringo District, Kenya, were tested. Leishmania genus assay sensitivity was 100% (14/14) and specificity was 84% (16/19). Visceral Leishmania assay sensitivity was 93% (13/14) and specificity 80% (4/5). Cutaneous leishmaniasis (CL) skin scrapes of patients from Honduras were also evaluated. Leishmania genus assay sensitivity was 100% (10/10). Visceral Leishmania assay specificity was 100% (10/10) from cutaneous leishmaniasis samples; no fluorescence above background was reported. These results show promise in a rapid, sensitive, and specific method for Leishmania direct detection from clinical samples.

Dual-Readout Immunochromatographic Assay by Utilizing MnO 2 Nanoflowers as the Unique Colorimetric/Chemiluminescent Probe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ouyang, Hui; Lu, Qian; Wang, Wenwen

Manganese dioxide nanoflowers (MnO2 NFs) were synthesized and utilized as a dual readout probe to develop a novel immunochromatographic test strip (ITS) for detecting pesticide residues using chlorpyrifos as the model analyte. MnO2 NFs-labeled antibody for chlorpyrifos was employed as the signal tracer for conducting the ITS. After 10-min competitive immunoreaction, the tracer antibody was captured by the immobilized immunogen on test line in the test strip, resulting in the accumulation of MnO2 NFs. The accumulation of MnO2 NFs led to the appearance of brown color on the test line, which could be easily observed by the naked eye asmore » a qualitative readout. Moreover, MnO2 NFs showed a remarkably enhancing effect on the luminol-H2O2 chemiluminescent (CL) system. Unlike peroxidase-like nanomaterials, the enhancing mechanism of MnO2 NFs was based on its oxidant activity to decompose H2O2 for forming reactive oxygen species. After initiating the CL system in the test zone, strong CL signal was collected as a quantitative readout to sensitively detect chlorpyrifos. Under optimal conditions, the linear range of chlorpyrifos was 0.1–50 ng/mL with a low detection limit of 0.033 ng/mL (S/N = 3). The reliability of the dual-readout ITS was successfully demonstrated by the application on traditional Chinese medicine and environmental water samples. Due to the simultaneous rapid-qualitative and sensitive-quantitative detection, the dual-readout protocol provides a promising strategy for rapid screening and field assay on various areas such as environmental monitoring, food safety and point-of-care testing.« less

An amplified chemiluminescence system based on Si-doped carbon dots for detection of catecholamines.

PubMed

Amjadi, Mohammad; Hallaj, Tooba; Manzoori, Jamshid L; Shahbazsaghir, Tahmineh

2018-08-05

We report on a chemiluminescence (CL) system based on simultaneous enhancing effect of Si-doped carbon dots (Si-CDs) and cetyltrimethylammonium bromide (CTAB) on HCO 3 - -H 2 O 2 reaction . The possible CL mechanism is investigated and discussed. Excited-state Si-CDs was found to be the final emitting species, which are probably produced via electron and hole injection by oxy-radicals. The effect of several other heteroatom-doped CDs and undoped CDs was also investigated and compared with Si-CDs. Furthermore, it was found that catecholamines such as dopamine, adrenaline and noradrenaline remarkably diminish the CL intensity of Si-CD-HCO 3 - -H 2 O 2 -CTAB system. By taking advantage of this fact, a sensitive probe was designed for determination of dopamine, adrenaline and noradrenaline with a limit of detection of 0.07, 0.60 and 0.01 μM, respectively. The method was applied to the determination of catecholamines in human plasma samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Molecular Epidemiological Survey of Cutaneous Leishmaniasis in Two Highly Endemic Metropolises of Iran, Application of FTA Cards for DNA Extraction From Giemsa-Stained Slides.

PubMed

Izadi, Shahrokh; Mirhendi, Hossein; Jalalizand, Niloufar; Khodadadi, Hossein; Mohebali, Mehdi; Nekoeian, Shahram; Jamshidi, Ali; Ghatee, Mohammad Amin

2016-02-01

PCR has been used for confirmation of leishmaniasis in epidemiological studies, but complexity of DNA extraction and PCR approach has confined its routine use in developing countries. In this study, recent epidemiological situation of cutaneous leishmaniasis (CL) in two hyper-endemic metropolises of Shiraz and Isfahan in Iran was studied using DNA extraction by commercial FTA cards and kinetoplastid DNA (kDNA)-PCR amplification for detection/identification of Leishmania directly from stained skin scraping imprints. Fifty four and 30 samples were collected from clinically diagnosed CL patients referred to clinical laboratories of leishmaniasis control centers in Isfahan and Shiraz cities, respectively. The samples were examined by direct microscopy and then scrapings of the stained smears were applied to FTA cards and used directly as DNA source in a nested-PCR to amplify kDNA to detect and identify Leishmania species. Fifty four of 84 (64.2%) slides obtained from patients had positive results microscopically, while 79/84 (94%) of slides had positive results by FTA card-nested-PCR. PCR and microscopy showed a sensitivity of 96.4% and 64.2% and specificity of 100% and 100%, respectively. Interestingly, Leishmania major as causative agent of zoonotic CL was identified in 100% and 90.7% of CL cases from Isfahan and Shiraz cities, respectively, but L. tropica was detected from only 9.3% of cases from Shiraz city. All cases from central regions of Shiraz were L. tropica and no CL case was found in Isfahan central areas. Filter paper-based DNA extraction can facilitate routine use of PCR for diagnosis of CL in research and diagnostic laboratories in Iran and countries with similar conditions. Epidemiologic changes including dominancy of L. major in suburbs of Shiraz and Isfahan metropolises where anthroponotic CL caused by L. tropica had been established, showed necessity of precise studies on CL epidemiology in old urban and newly added districts in the suburbs.

First direct detection limits on sub-GeV dark matter from XENON10.

PubMed

Essig, Rouven; Manalaysay, Aaron; Mardon, Jeremy; Sorensen, Peter; Volansky, Tomer

2012-07-13

The first direct detection limits on dark matter in the MeV to GeV mass range are presented, using XENON10 data. Such light dark matter can scatter with electrons, causing ionization of atoms in a detector target material and leading to single- or few-electron events. We use 15  kg day of data acquired in 2006 to set limits on the dark-matter-electron scattering cross section. The strongest bound is obtained at 100 MeV where σ(e)<3×10(-38)  cm2 at 90% C.L., while dark-matter masses between 20 MeV and 1 GeV are bounded by σ(e)<10(-37)  cm2 at 90% C.L. This analysis provides a first proof of principle that direct detection experiments can be sensitive to dark-matter candidates with masses well below the GeV scale.

The effect of a solid surface on the segregation and melting of salt hydrates.

PubMed

Zhang, Yu; Anim-Danso, Emmanuel; Dhinojwala, Ali

2014-10-22

Considering the importance of salt and water on earth, the crystallization of salt hydrates next to solid surfaces has important implications in physical and biological sciences. Heterogeneous nucleation is driven by surface interactions, but our understanding of hydrate formation near surfaces is limited. Here, we have studied the hydrate formation of three commonly prevalent salts, MgCl2, CaCl2, and NaCl, next to a sapphire substrate using surface sensitive infrared-visible sum frequency generation (SFG) spectroscopy. SFG spectroscopy can detect the crystallization and melting of salt hydrates at the interface by observing the changes in the intensity and the location of the cocrystallized water hydroxyl peaks (3200-3600 cm(-1)). The results indicate that the surface crystal structures of these three hydrates are similar to those in the bulk. For the NaCl solution, the brine solution is segregated next to the sapphire substrate after the formation of the ice phase. In contrast, the MgCl2 and CaCl2 surface hydrate crystals are interdispersed with nanometer-size ice crystals. The nanosize ice crystals melt at much lower temperatures than bulk ice crystals. For NaCl and MgCl2 solution, the NaCl hydrates prefer to crystallize next to the sapphire substrate instead of the ice crystals and MgCl2 hydrates.

Doping-assisted low-pressure photoionization mass spectrometry for the real-time detection of lung cancer-related volatile organic compounds.

PubMed

Li, Zhen; Xu, Ce; Shu, Jinian; Yang, Bo; Zou, Yao

2017-04-01

Real-time detection of lung cancer-related volatile organic compounds (VOCs) is a promising, non-intrusive technique for lung cancer (LC) prescreening. In this study, a novel method was designed to enhance the detection selectivity and sensitivity of LC-related polar VOCs by dichloromethane (CH 2 Cl 2 ) doping-assisted low-pressure photoionization mass spectrometry (LPPI-MS). Compared with conventional LPPI-MS, CH 2 Cl 2 doping-assisted LPPI-MS boosted the peak intensities of n-propanol, n-pentanal, acetone, and butyl acetate in nitrogen specifically by 53, 18, 16, and 43 times, respectively. The signal intensities of their daughter ions were inhibited or reduced. At relative humidity (RH) of 20%, the sensitivities of n-propanol, n-pentanal, acetone, and butyl acetate detection ranged from 116 to 452 counts/ppbv with a detection time of 10s and R 2 >0.99 for the linear calibration curves. The method was also applicable under higher RH levels of 50% and 90%. Breath samples obtained from 10 volunteers and spiked samples were investigated. Eight-fold enhancements in the signal intensities of polar VOCs were observed in the normal and spiked samples. These preliminary results demonstrate the efficacy of the dichloromethane doping-assisted LPPI technique for the detection of LC-related polar VOCs. Further studies are indispensible to illustrating the detailed mechanism and applying the technique to breath diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Unsupervised Gaussian Mixture-Model With Expectation Maximization for Detecting Glaucomatous Progression in Standard Automated Perimetry Visual Fields.

PubMed

Yousefi, Siamak; Balasubramanian, Madhusudhanan; Goldbaum, Michael H; Medeiros, Felipe A; Zangwill, Linda M; Weinreb, Robert N; Liebmann, Jeffrey M; Girkin, Christopher A; Bowd, Christopher

2016-05-01

To validate Gaussian mixture-model with expectation maximization (GEM) and variational Bayesian independent component analysis mixture-models (VIM) for detecting glaucomatous progression along visual field (VF) defect patterns (GEM-progression of patterns (POP) and VIM-POP). To compare GEM-POP and VIM-POP with other methods. GEM and VIM models separated cross-sectional abnormal VFs from 859 eyes and normal VFs from 1117 eyes into abnormal and normal clusters. Clusters were decomposed into independent axes. The confidence limit (CL) of stability was established for each axis with a set of 84 stable eyes. Sensitivity for detecting progression was assessed in a sample of 83 eyes with known progressive glaucomatous optic neuropathy (PGON). Eyes were classified as progressed if any defect pattern progressed beyond the CL of stability. Performance of GEM-POP and VIM-POP was compared to point-wise linear regression (PLR), permutation analysis of PLR (PoPLR), and linear regression (LR) of mean deviation (MD), and visual field index (VFI). Sensitivity and specificity for detecting glaucomatous VFs were 89.9% and 93.8%, respectively, for GEM and 93.0% and 97.0%, respectively, for VIM. Receiver operating characteristic (ROC) curve areas for classifying progressed eyes were 0.82 for VIM-POP, 0.86 for GEM-POP, 0.81 for PoPLR, 0.69 for LR of MD, and 0.76 for LR of VFI. GEM-POP was significantly more sensitive to PGON than PoPLR and linear regression of MD and VFI in our sample, while providing localized progression information. Detection of glaucomatous progression can be improved by assessing longitudinal changes in localized patterns of glaucomatous defect identified by unsupervised machine learning.

Enhancement of periodate-hydrogen peroxide chemiluminescence by nitrogen doped carbon dots and its application for the determination of pyrogallol and gallic acid.

PubMed

Shah, Syed Niaz Ali; Li, Haifang; Lin, Jin-Ming

2016-06-01

A new sensitized chemiluminescence (CL) was developed to broaden the analytical application of KIO4-H2O2 system. The nitrogen doped carbon dots (N-CDs) dramatically boosted the CL intensity of KIO4-H2O2 system which was further enriched by basic medium. In light of EPR analysis, free radical scavenging studies and CL spectra the detail mechanism for the enhancement was conferred in the presence of N-CDs and NaOH. The results suggested that CL of KIO4-H2O2 system in the presence and absence of N-CDs and NaOH proceeds via radical pathway. The enhanced CL was used for the determination of pyrogallol and gallic acid in range of 1.0×10(-4)-1.0×10(-7)M with 4.6×10(-8) and 6.1×10(-8)M limit of detection respectively. The relative standard deviation (RSD) at a concentration of 10(-5) for gallic acid and pyrogallol was 1.4% and 2.3% respectively (n=11). The attained results unveil that the present method is sensitive, faster, simpler and less costly compared to other methods and could be applied to determine polyphenols in real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Facile synthesis of hollow Co3O4 microspheres and its use as a rapid responsive CL sensor of combustible gases.

PubMed

Teng, Fei; Yao, Wenqing; Zheng, Youfei; Ma, Yutao; Xu, Tongguang; Gao, Guizhi; Liang, Shuhui; Teng, Yang; Zhu, Yongfa

2008-09-15

The hollow Co(3)O(4) microspheres (HCMs) were prepared by the carbonaceous templates, which did not need the surface pretreatment. The chemiluminescence (CL) and catalytic properties for CO oxidation over these hollow samples were evaluated. The samples were characterized by scanning electron microscopy (SEM), energy disperse spectra (EDS), transmission electron microscopy (TEM), selected area electron diffraction (ED), X-ray diffraction (XRD), temperature-programmed desorption (TPD) and N(2) adsorption. The influences of filter' band length, flow rate of gas, test temperature, and particle structure on CL intensities were mainly investigated. It was found that compared with the solid Co(3)O(4) particles (SCPs), HCMs had a stronger CL intensity, which was ascribed to its hollow structure; and that CL properties of the catalysts were well correlated with their reaction activities. Moreover, HCMs were used to fabricate a highly sensitive gas detector, which is a rapid and effective method for the selection of catalysts or the detection of environmental deleterious gases.

Determination of L-phenylalanine on-line based on molecularly imprinted polymeric microspheres and flow injection chemiluminescence

NASA Astrophysics Data System (ADS)

Qiu, Huamin; Xi, Yulei; Lu, Fuguang; Fan, Lulu; Luo, Chuannan

2012-02-01

A novel molecular imprinting-chemiluminescence (MIP-CL) sensor for the determination of L-phenylalanine (Phe) using molecularly imprinted polymer (MIP) as recognition element is reported. The Phe-MIP was synthesized using acrylamide (AM) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker, 2,2-azobisisobutyronitrile (AIBN) as initiator and the polymers' properties were characterized. Then the synthesized MIP was employed as recognition element by packing into flow cell to establish a novel flow injection CL sensor. The CL intensity responded linearly to the concentration of Phe in the range 1.3 × 10 -6 to 5.44 × 10 -4 mol/L with a detection limit of 6.23 × 10 -7 mol/L (3 σ), which is lower than that of conventional methods. The sensor is reusable and has a great improvement in sensitivity and selectivity for CL analysis. As a result, the new MIP-CL sensor had been successfully applied to the determination of Phe in samples.

CdTe quantum dots@luminol as signal amplification system for chrysoidine with chemiluminescence-chitosan/graphene oxide-magnetite-molecularly imprinting sensor

NASA Astrophysics Data System (ADS)

Duan, Huimin; Li, Leilei; Wang, Xiaojiao; Wang, Yanhui; Li, Jianbo; Luo, Chuannan

2016-01-01

A sensitive chemiluminescence (CL) sensor based on chemiluminescence resonance energy transfer (CRET) in CdTe quantum dots@luminol (CdTe QDs@luminol) nanomaterials combined with chitosan/graphene oxide-magnetite-molecularly imprinted polymer (Cs/GM-MIP) for sensing chrysoidine was developed. CdTe QDs@luminol was designed to not only amplify the signal of CL but also reduce luminol consumption in the detection of chrysoidine. On the basis of the abundant hydroxy and amino, Cs and graphene oxide were introduced into the GM-MIP to improve the adsorption ability. The adsorption capacities of chrysoidine by both Cs/GM-MIP and non-imprinted polymer (Cs/GM-NIP) were investigated, and the CdTe QDs@luminol and Cs/GM-MIP were characterized by UV-vis, FTIR, SEM and TEM. The proposed sensor can detect chrysoidine within a linear range of 1.0 × 10- 7 - 1.0 × 10- 5 mol/L with a detection limit of 3.2 × 10- 8 mol/L (3δ) due to considerable chemiluminescence signal enhancement of the CdTe quantum dots@luminol detector and the high selectivity of the Cs/GM-MIP system. Under the optimal conditions of CL, the CdTe QDs@luminol-Cs/GM-MIP-CL sensor was used for chrysoidine determination in samples with satisfactory recoveries in the range of 90-107%.

Rapid and sensitive detection of Lily symptomless virus by reverse transcription loop-mediated isothermal amplification.

PubMed

He, Xiangfeng; Xue, Fei; Xu, Shufa; Wang, Wenhe

2016-12-01

Lily symptomless virus (LSV) is one of the most prevalent viruses that infect lily plants worldwide. A rapid and sensitive reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay was developed for detection of LSV, using two primer pairs that specifically amplified the conserved sequence of LSV coat protein. The optimum reaction conditions were as follows: 4mM MgCl 2 and 0.8M betaine with incubation at 64°C for 30min. The limit of detection of LSV from infected lily leaves was 10-fold higher for RT-LAMP than for conventional RT-PCR. Moreover, RT-LAMP detected LSV in not only symptomatic, but also in symptomless tissues of infected plants. These findings indicate that our RT-LAMP method for LSV can serve as a low-cost, simple, and rapid alternative to conventional detection assays. Copyright © 2016 Elsevier B.V. All rights reserved.

A highly sensitive and temporal visualization system for gaseous ethanol with chemiluminescence enhancer.

PubMed

Arakawa, Takahiro; Ando, Eri; Wang, Xin; Kumiko, Miyajima; Kudo, Hiroyuki; Saito, Hirokazu; Mitani, Tomoyo; Takahashi, Mitsuo; Mitsubayashi, Kohji

2012-01-01

A two-dimensional gaseous ethanol visualization system has been developed and demonstrated using a horseradish peroxidase-luminol-hydrogen peroxide system with high-purity luminol solution and a chemiluminescence (CL) enhancer. This system measures ethanol concentrations as intensities of CL via the luminol reaction. CL was emitted when the gaseous ethanol was injected onto an enzyme-immobilized membrane, which was employed as a screen for two-dimensional gas visualization. The average intensity of CL on the substrate was linearly related to the concentration of standard ethanol gas. These results were compared with the CL intensity of the CCD camera recording image in the visualization system. This system is available for gas components not only for spatial but also for temporal analysis in real time. A high-purity sodium salt HG solution (L-HG) instead of standard luminol solution and an enhancer, eosin Y (EY) solution, were adapted for improvement of CL intensity of the system. The visualization of gaseous ethanol was achieved at a detection limit of 3 ppm at optimized concentrations of L-HG solution and EY. Copyright © 2011 John Wiley & Sons, Ltd.

Environmental monitoring of bleached kraft pulp mill chlorophenolic compounds in a northern Canadian river system.

PubMed

Owens, J W; Swanson, S M; Birkholz, D A

1994-07-01

The environmental transport of pulp mill effluent compounds and the exposure of two fish species has been monitored by parallel analyses of effluent, water column and suspended sediment samples, and fish bile and muscle. Compounds analyzed included over 20 chlorophenolic compounds and 12 fatty and resin acids. The concentration of chlorophenols varied with seasonal river flows and mill process changes such as the substitution of chlorine dioxide (ClO2) for chlorine gas (Cl2) in the bleach plant. At 100% (ClO2) substitution, the effluent and the water column concentrations of most chlorophenolics approached the analytical detection limits of 0.1-1 parts per billion. Chlorophenolic and fatty/resin acid compounds were detected in the bile of both mountain whitefish (Prosopium williamsoni) and longnose sucker (Catostomus catostomus), but were rarely detected in fillets. Fish bile concentrations were observed in an apparent spatial gradient as far as 230 km downstream of the mill. A depuration experiment with fish held in uncontaminated water for eight days indicated a rapid decrease in chlorophenol levels. These observations corroborate previous investigations that chlorophenolic compounds are rapidly excreted and can be used as sensitive markers for recent exposure to mill effluents.

NaNO3/NaCl Oxidant and Polyethylene Glycol (PEG) Capped Gold Nanoparticles (AuNPs) as a Novel Green Route for AuNPs Detection in Electrochemical Biosensors.

PubMed

López-Marzo, Adaris M; Hoyos-de-la-Torre, Raquel; Baldrich, Eva

2018-03-20

Gold nanoparticles (AuNPs) have been exploited as signal-producing tags in electrochemical biosensors. However, the electrochemical detection of AuNPs is currently performed using corrosive acid solutions, which may raise health and environmental concerns. Here, oxidant salts, and specifically the environmentally friendly and occupational safe NaNO 3 /NaCl mixture, have been evaluated for the first time as potential alternatives to the acid solutions traditionally used for AuNPs electrooxidation. In addition, a new strategy to improve the sensitivity of the biosensor through PEG-based ligand exchange to produce less compact and easier to oxidize AuNPs immunoconjugates is presented too. As we show, the electrochemical immunosensor using NaNO 3 /NaCl measurement solution for AuNPs electrooxidation and detection, coupled to the employment of PEG-capped nanoimmunoconjugates, produced results comparable to classical HCl detection. The procedure developed was next tested for human matrix metallopeptidase-9 (hMMP9) analysis, exhibiting a 0.18-23 ng/mL linear range, a detection limit of 0.06 ng/mL, and recoveries between 95 and 105% in spiked human plasma. These results show that the procedure developed is applicable to the analysis of protein biomarkers in blood plasma and could contribute to the development of more environmentally friendly AuNP-based electrochemical biosensors.

Evaluating evidence for Cl sources and oxidation chemistry in a coastal, urban environment

NASA Astrophysics Data System (ADS)

Young, C. J.; Washenfelder, R. A.; Edwards, P. M.; Parrish, D. D.; Gilman, J. B.; Kuster, W. C.; Mielke, L. H.; Osthoff, H. D.; Tsai, C.; Pikelnaya, O.; Stutz, J.; Veres, P. R.; Roberts, J. M.; Griffith, S.; Dusanter, S.; Stevens, P. S.; Flynn, J.; Grossberg, N.; Lefer, B.; Holloway, J. S.; Peischl, J.; Ryerson, T. B.; Atlas, E. L.; Blake, D. R.; Brown, S. S.

2013-05-01

The role of chlorine atoms (Cl) in atmospheric oxidation was traditionally thought to be limited to the marine boundary layer, where they are produced through heterogeneous reactions involving sea salt. However, recent observation of photolytic Cl precursors (ClNO2 and Cl2) formed from anthropogenic pollution has expanded the potential importance of Cl to include coastal and continental urban areas. Measurements of ClNO2 in Los Angeles during CalNex showed it to be an important primary (first generation) radical source. Ratios of volatile organic compounds (VOCs) have been proposed as a sensitive method to quantify Cl oxidation, but have shown little evidence for a significant role of Cl outside of the Arctic. We used a box model with the Master Chemical Mechanism (MCM v3.2) chemistry scheme, constrained by observations in Los Angeles, to examine the Cl-sensitivity of the most commonly used VOC ratios (i-butane, n-butane, and propane) as a function of NOx and secondary radical production. Model results indicated these and faster reacting VOC tracer ratios could not detect the influence of Cl unless the sustained ratio of OH to Cl was below 200. However, the model results also show that secondary (second generation) OH production resulting from Cl oxidation of VOCs is strongly influenced by NOx, and that this effect can obscure the importance of Cl as a primary oxidant. Calculated concentrations of Cl showed a maximum in mid-morning due to a photolytic source from ClNO2 and loss primarily to reactions with VOCs. The OH to Cl ratio was below 200 for approximately three hours in the morning, but Cl oxidation was not evident from the measured ratios of VOCs. Instead, model simulations show that secondary OH production causes VOC ratios to follow the values expected for OH oxidation despite the significant input of primary Cl from ClNO2 photolysis in the morning. Despite the prevalence of secondary OH as an oxidant in Los Angeles, Cl may play an important role in tropospheric chemistry. The reactivity of Cl in Los Angeles during CalNex was more than an order of magnitude larger than that of OH. In addition, because of its reactivity toward different classes of VOCs and its greater propensity to participate in chain propagation rather than sink reactions, Cl atoms have a different impact on regional atmospheric oxidation than do OH radicals.

Chitosan-induced Au/Ag nanoalloy dispersed in IL and application in fabricating an ultrasensitive glucose biosensor based on luminol-H₂O₂-Cu²⁺/IL chemiluminescence system.

PubMed

Chaichi, M J; Alijanpour, S O

2014-11-01

A novel glucose biosensor based on the chemiluminescence (CL) detection of enzymatically generated hydrogen peroxide (H₂O₂) was constructed by one covalent immobilization of glucose oxidase (GOD) in glutaraldehyde-functionalized glass cell. In following, chitosan-induced Au/Ag nanoparticles dispersed in ion liquid (IL) were synthesised and immobilized on it. Herein, chitosan molecules acted as both the reducing and stabilizing agent for the preparation of NPs and also, as a coupling agent GOD and Au/Ag alloy NPs. In addition to catalyze luminol CL reaction, these NPs offered excellent catalytic activity toward hydrogen peroxide generation in enzymatic reaction between GOD and glucose. The used IL in fabrication of biosensor increased its stability. Also, IL alongside Cu(2+) accelerated enzymatic and CL reaction kinetic, and decreased luminol CL reaction optimum pH to 7.5 which would enable sensitive and precision determination of glucose. Under optimum condition, linear response range of glucose was found to be 1.0 × 10(-6)-7.5 × 10(-3)M, and detection limit was 4.0 × 10(-7)M. The CL biosensor exhibited good storage stability, i.e., 90% of its initial response was retained after 2 months storage at pH 7.0. The present CL biosensor has been applied satisfactory to analysis of glucose in real serum and urine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

CLCNKB mutations causing mild Bartter syndrome profoundly alter the pH and Ca2+ dependence of ClC-Kb channels.

PubMed

Andrini, Olga; Keck, Mathilde; L'Hoste, Sébastien; Briones, Rodolfo; Mansour-Hendili, Lamisse; Grand, Teddy; Sepúlveda, Francisco V; Blanchard, Anne; Lourdel, Stéphane; Vargas-Poussou, Rosa; Teulon, Jacques

2014-09-01

ClC-Kb, a member of the ClC family of Cl(-) channels/transporters, plays a major role in the absorption of NaCl in the distal nephron. CLCNKB mutations cause Bartter syndrome type 3, a hereditary renal salt-wasting tubulopathy. Here, we investigate the functional consequences of a Val to Met substitution at position 170 (V170M, α helix F), which was detected in eight patients displaying a mild phenotype. Conductance and surface expression were reduced by ~40-50 %. The regulation of channel activity by external H(+) and Ca(2+) is a characteristic property of ClC-Kb. Inhibition by external H(+) was dramatically altered, with pKH shifting from 7.6 to 6.0. Stimulation by external Ca(2+) on the other hand was no longer detectable at pH 7.4, but was still present at acidic pH values. Functionally, these regulatory modifications partly counterbalance the reduced surface expression by rendering V170M hyperactive. Pathogenic Met170 seems to interact with another methionine on α helix H (Met227) since diverse mutations at this site partly removed pH sensitivity alterations of V170M ClC-Kb. Exploring other disease-associated mutations, we found that a Pro to Leu substitution at position 124 (α helix D, Simon et al., Nat Genet 1997, 17:171-178) had functional consequences similar to those of V170M. In conclusion, we report here for the first time that ClC-Kb disease-causing mutations located around the selectivity filter can result in both reduced surface expression and hyperactivity in heterologous expression systems. This interplay must be considered when analyzing the mild phenotype of patients with type 3 Bartter syndrome.

Chloroquine uptake, altered partitioning and the basis of drug resistance: evidence for chloride-dependent ionic regulation.

PubMed

Martiney, J A; Ferrer, A S; Cerami, A; Dzekunov, S; Roepe, P

1999-01-01

The biochemical mechanism of chloroquine resistance in Plasmodium falciparum remains unknown. We postulated that chloroquine-resistant strains could alter ion fluxes that then indirectly control drug accumulation within the parasite by affecting pH and/or membrane potential ('altered partitioning mechanism'). Two principal intracellular pH-regulating systems in many cell types are the amiloride-sensitive Na+/H+ exchanger (NHE), and the sodium-independent, stilbene-sensitive Cl-/HCO3- antiporter (AE). We report that under physiological conditions (balanced CO2 and HCO3-) chloroquine uptake and susceptibility are not altered by amiloride analogues. We also do not detect a significant difference in NHE activity between chloroquine-sensitive and chloroquine-resistant strains via single cell photometry methods. AE activity is dependent on the intracellular and extracellular concentrations of Cl- and HCO3- ions. Chloroquine-resistant strains differentially respond to experimental modifications in chloride-dependent homeostasis, including growth, cytoplasmic pH and pH regulation. Chloroquine susceptibility is altered by stilbene DIDS only on chloroquine-resistant strains. Our results suggest that a Cl(-)-dependent system (perhaps AE) has a significant effect on the uptake of chloroquine by the infected erythrocyte, and that alterations of this biophysical parameter may be part of the mechanism of chloroquine resistance in P. falciparum.

Innovations in Nuclear Imaging Instrumentation: Cerenkov Imaging.

PubMed

Tamura, Ryo; Pratt, Edwin C; Grimm, Jan

2018-07-01

Cerenkov luminescence (CL) is blue glow light produced by charged subatomic particles travelling faster than the phase velocity of light in a dielectric medium such as water or tissue. CL was first discovered in 1934, but for biomedical research it was recognized only in 2009 after advances in optical camera sensors brought the required high sensitivity. Recently, applications of CL from clinical radionuclides have been rapidly expanding to include not only preclinical and clinical biomedical imaging but also an approach to therapy. Cerenkov Luminescence Imaging (CLI) utilizes CL generated from clinically relevant radionuclides alongside optical imaging instrumentation. CLI is advantageous over traditional nuclear imaging methods in terms of infrastructure cost, resolution, and imaging time. Furthermore, CLI is a truly multimodal imaging method where the same agent can be detected by two independent modalities, with optical (CL) imaging and with positron emission tomography (PET) imaging. CL has been combined with small molecules, biomolecules and nanoparticles to improve diagnosis and therapy in cancer research. Here, we cover the fundamental breakthroughs and recent advances in reagents and instrumentation methods for CLI as well as therapeutic application of CL. Copyright © 2018 Elsevier Inc. All rights reserved.

Epidemiology of Imported Cutaneous Leishmaniasis at the Hospital for Tropical Diseases, London, United Kingdom: Use of Polymerase Chain Reaction to Identify the Species

PubMed Central

Wall, Emma C.; Watson, Julie; Armstrong, Margaret; Chiodini, Peter L.; Lockwood, Diana N.

2012-01-01

This study reviewed all patients diagnosed with imported cutaneous leishmaniasis (CL) at the Hospital for Tropical Diseases in London, United Kingdom, over an 11-year period. Diagnostic and epidemiologic information was collected prospectively for all patients with imported CL to this hospital during 1998–2009. A total of 223 patients were given a diagnosis of CL. Ninety patients were diagnosed with Old World CL, which was caused most commonly by Leishmania donovani complex (n = 20). A total of 71% were tourists to the Mediterranean region, 36% were migrants or visiting friends and relatives, and 17% were soldiers. One hundred thirty-three patients were given a diagnosis of New World CL. The Leishmania subgenus Viannia caused 97 of these cases; 44% of these were in backpackers and 29% were in soldiers. Polymerase chain reaction was more sensitive and faster for detecting Leishmania DNA (86% for Old World CL and 96% for New World CL) than culture. This is the largest study of imported leishmaniasis, and demonstrates that tourists to the Mediterranean and backpackers in Central and South America are at risk for this disease. PMID:22232460

Downregulation of ClC-3 in dorsal root ganglia neurons contributes to mechanical hypersensitivity following peripheral nerve injury.

PubMed

Pang, Rui-Ping; Xie, Man-Xiu; Yang, Jie; Shen, Kai-Feng; Chen, Xi; Su, Ying-Xue; Yang, Chao; Tao, Jing; Liang, Si-Jia; Zhou, Jia-Guo; Zhu, He-Quan; Wei, Xu-Hong; Li, Yong-Yong; Qin, Zhi-Hai; Liu, Xian-Guo

2016-11-01

ClC-3 chloride channel/antiporter has been demonstrated to play an important role in synaptic transmission in central nervous system. However, its expression and function in sensory neurons is poorly understood. In present work, we found that ClC-3 is expressed at high levels in dorsal root ganglia (DRG). Co-immunofluorescent data showed that ClC-3 is mainly distributed in A- and C-type nociceptive neurons. ClC-3 expression in DRG is decreased in the spared nerve injury (SNI) model of neuropathic pain. Knockdown of local ClC-3 in DRG neurons with siRNA increased mechanical sensitivity in naïve rats, while overexpression of ClC-3 reversed the hypersensitivity to mechanical stimuli after peripheral nerve injury. In addition, genetic deletion of ClC-3 enhances mouse mechanical sensitivity but did not affect thermal and cold threshold. Restoration of ClC-3 expression in ClC-3 deficient mice reversed the mechanical sensitivity. Mechanistically, loss of ClC-3 enhanced mechanical sensitivity through increasing the excitability of DRG neurons. These data indicate that ClC-3 is an endogenous inhibitor of neuropathic pain development. Downregulation of ClC-3 by peripheral nerve injury is critical for mechanical hypersensitivity. Our findings suggest that ClC-3 is a novel therapeutic target for treating neuropathic pain. Copyright © 2016 Elsevier Ltd. All rights reserved.

An enhanced cerium(IV)-rhodamine 6G chemiluminescence system using guest-host interactions in a lab-on-a-chip platform for estimating the total phenolic content in food samples.

PubMed

Al Haddabi, Buthaina; Al Lawati, Haider A J; Suliman, FakhrEldin O

2016-04-01

Two chemiluminescence-microfluidic (CL-MF) systems, e.g., Ce(IV)-rhodamine B (RB) and Ce(IV)-rhodamine 6G (R6G), for the determination of the total phenolic content in teas and some sweeteners were evaluated. The results indicated that the Ce(IV)-R6G system was more sensitive in comparison to the Ce(IV)-RB CL system. Therefore, a simple (CL-MF) method based on the CL of Ce(IV)-R6G was developed, and the sensitivity, selectivity and stability of this system were evaluated. Selected phenolic compounds (PCs), such as quercetin (QRC), catechin (CAT), rutin (RUT), gallic acid (GA), caffeic acid (CA) and syringic acid (SA), produced analytically useful chemiluminescence signals with low detection limits ranging from 0.35 nmol L(-1) for QRC to 11.31 nmol L(-1) for SA. The mixing sequence and the chip design were crucial, as the sensitivity and reproducibility could be substantially affected by these two factors. In addition, the anionic surfactant (i.e., sodium dodecyl sulfate (SDS)) can significantly enhance the CL signal intensity by as much as 300% for the QRC solution. Spectroscopic studies indicated that the enhancement was due to a strong guest-host interaction between the cationic R6G molecules and the anionic amphiphilic environment. Other parameters that could affect the CL intensities of the PCs were carefully optimized. Finally, the method was successfully applied to tea and sweetener samples. Six different tea samples exhibited total phenolic/antioxidant levels from 7.32 to 13.5 g per 100g of sample with respect to GA. Four different sweetener samples were also analyzed and exhibited total phenolic/antioxidant levels from 500.9 to 3422.9 mg kg(-1) with respect to GA. The method was selective, rapid and sensitive when used to estimate the total phenolic/antioxidant level, and the results were in good agreement with those reported for honey and tea samples. Copyright © 2015 Elsevier B.V. All rights reserved.

New Fluorescent and Colorimetric Chemosensor for Detection of Cyanide with High Selectivity and Sensitivity in Aqueous Media.

PubMed

Zali-Boeini, Hassan; Zareh Jonaghani, Mohammad

2017-05-01

A fluorescent and colorimetric chemosensor for detection of cyanide ion based on a styryl quinoline derivative has been designed and synthesized. The chemosensor (E)-2-(4-mercaptostyryl)quinolin-8-ol L showed high selectivity for detection of cyanide over other anions such as F¯, Cl¯, Br¯, I¯, NO 3 ¯, SCN¯, N 3 ¯, ClO 4 ¯, H 2 PO 4 ¯, AcO¯, HCO 3 ¯, SO 4 2 ¯ and HSO 4 ¯in aqueous solution. The chemosensor L displayed an immediate visible and fluorescence changes from nearly colorless to orange and greenish-blue to brick-red upon addition of cyanide ion respectively. It is more likely, these distinct changes can be attributed to hydrogen bonding interaction between phenol group and cyanide anion leading to a 1:1 binding stoichiometry following with deprotonation of phenol group. The detection limit for chemosensor L toward CN¯ was 2.73× 10 -8  M. Thus, the chemosensor can be used efficiently and selectively for detection and monitoring of small amounts of cyanide ion in aqueous media.

Copper nanocluster-enhanced luminol chemiluminescence for high-selectivity sensing of tryptophan and phenylalanine.

PubMed

Borghei, Yasaman-Sadat; Hosseini, Morteza; Khoobi, Mehdi; Ganjali, Mohammad Reza

2017-09-01

A remarkable method for the highly sensitive detection of phenylalanine and tryptophan based on a chemiluminescence (CL) assay was reported. It was found that fluorescent copper nanoclusters capped with cysteine (Cys-CuNCs) strongly enhance the weak CL signal resulting from the reaction between luminol and H 2 O 2 . Of the amino acids tested, phenylalanine and tryptophan could enhance the above CL system sensitively. Under optimum conditions, this method was satisfactorily described by a linear calibration curve over a range of 1.0 × 10 -6 to 2.7 × 10 -5  M for phenylalanine and 1.0 × 10 -7 to 3.0 × 10 -5  M for tryptophan, respectively. The effect of various parameters such as Cys-CuNC concentration, H 2 O 2 concentration and pH on the intensity of the CL system were also studied. The main experimental advantage of the proposed method was its selectivity for two amino acids compared with others. To evaluate the applicability of the method to the analysis of a real biological sample it was used to determine tryptophan and phenylalanine in human serum and remarkable results were obtained. Copyright © 2017 John Wiley & Sons, Ltd.

Drought Sensitivity of the Carbon Isotope Composition of Leaf Dark-Respired CO2 in C3 (Leymus chinensis) and C4 (Chloris virgata and Hemarthria altissima) Grasses in Northeast China

PubMed Central

Zhong, Shangzhi; Chai, Hua; Xu, Yueqiao; Li, Yan; Ma, Jian-Ying; Sun, Wei

2017-01-01

Whether photosynthetic pathway differences exist in the amplitude of nighttime variations in the carbon isotope composition of leaf dark-respired CO2 (δ13Cl) and respiratory apparent isotope fractionation relative to biomass (ΔR,biomass) in response to drought stress is unclear. These differences, if present, would be important for the partitioning of C3-C4 mixed ecosystem C fluxes. We measured δ13Cl, the δ13C of biomass and of potential respiratory substrates and leaf gas exchange in one C3 (Leymus chinensis) and two C4 (Chloris virgata and Hemarthria altissima) grasses during a manipulated drought period. For all studied grasses, δ13Cl decreased from 21:00 to 03:00 h. The magnitude of the nighttime shift in δ13Cl decreased with increasing drought stress. The δ13Cl values were correlated with the δ13C of respiratory substrates, whereas the magnitude of the nighttime shift in δ13Cl strongly depended on the daytime carbon assimilation rate and the range of nighttime variations in the respiratory substrate content. The ΔR,biomass in the C3 and C4 grasses varied in opposite directions with the intensification of the drought stress. The contribution of C4 plant-associated carbon flux is likely to be overestimated if carbon isotope signatures are used for the partitioning of ecosystem carbon exchange and the δ13C of biomass is used as a substitute for leaf dark-respired CO2. The detected drought sensitivities in δ13Cl and differences in respiratory apparent isotope fractionation between C3 and C4 grasses have marked implications for isotope partitioning studies at the ecosystem level. PMID:29375587

Anion exchange pathways for Cl sup minus transport in rabbit renal microvillus membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karniski, L.P.; Aronson, P.S.

1987-09-01

The authors evaluated the mechanisms of chloride transport in microvillus membrane vesicles isolated from the rabbit renal cortex. The presence of Cl-formate exchange was confirmed. Outward gradients of oxaloacetate, HCO{sub 3}, acetate, lactate, succinate, sulfate, and p-aminohippurate (PAH) stimulated the rate of Cl uptake minimally or not at all. However, an outward gradient of oxalate stimulated Cl uptake by 70%, and an outward Cl gradient induced uphill oxalate uptake, indicting Cl-oxalate exchange. Moreover, an outward formate gradient induced uphill oxalate uptake, indicating formate-oxalate exchange. Studies of inhibitor and substrate specificity indicated the probably operation of at least two separate anionmore » exchangers in mediating Cl transport. The Cl-formate exchanger accepted Cl and formate as substrates, had little or no affinity for oxalate, was sensitive to inhibition by furosemide, and was less sensitive to inhibition by 4,4{prime}-diisothiocyanostilbene-2,2{prime}-disulfonic acid (DIDS). The Cl (formate)-oxalate exchanger also accepted Cl and formate as substrates but had high affinity for oxalate, was highly sensitive to inhibition by DIDS, and was less sensitive to inhibition by furosemide. The Cl-formate exchanger was electroneutral, whereas the Cl (formate)-oxalate exchanger was electrogenic. They conclude that at least separate anion exchangers mediating Cl transport are present on the luminal membrane of the rabbit proximal tubule cell. These exchangers may play important roles in mediating transtubular Cl and oxalate transport in this nephron segment.« less

Gas chromatography coupled to tunable pulsed glow discharge time-of-flight mass spectrometry for environmental analysis.

PubMed

Solà-Vázquez, Auristela; Lara-Gonzalo, Azucena; Costa-Fernández, José M; Pereiro, Rosario; Sanz-Medel, Alfredo

2010-05-01

A tuneable microsecond pulsed direct current glow discharge (GD)-time-of-flight mass spectrometer MS(TOF) developed in our laboratory was coupled to a gas chromatograph (GC) to obtain sequential collection of the mass spectra, at different temporal regimes occurring in the GD pulses, during elution of the analytes. The capabilities of this set-up were explored using a mixture of volatile organic compounds of environmental concern: BrClCH, Cl(3)CH, Cl(4)C, BrCl(2)CH, Br(2)ClCH, Br(3)CH. The experimental parameters of the GC-pulsed GD-MS(TOF) prototype were optimized in order to separate appropriately and analyze the six selected organic compounds, and two GC carrier gases, helium and nitrogen, were evaluated. Mass spectra for all analytes were obtained in the prepeak, plateau and afterpeak temporal regimes of the pulsed GD. Results showed that helium offered the best elemental sensitivity, while nitrogen provided higher signal intensities for fragments and molecular peaks. The analytical performance characteristics were also worked out for each analyte. Absolute detection limits obtained were in the order of ng. In a second step, headspace solid phase microextraction (HS SPME), as sample preparation and preconcentration technique, was evaluated for the quantification of the compounds under study, in order to achieve the required analytical sensitivity for trihalomethanes European Union (EU) environmental legislation. The analytical figures of merit obtained using the proposed methodology showed rather good detection limits (between 2 and 13 microg L(-1) depending on the analyte). In fact, the developed methodology met the EU legislation requirements (the maximum level permitted in tap water for the "total trihalomethanes" is set at 100 microg L(-1)). Real analysis of drinking water and river water were successfully carried out. To our knowledge this is the first application of GC-pulsed GD-MS(TOF) for the analysis of real samples. Its ability to provide elemental, fragments and molecular information of the organic compounds is demonstrated.

Solid polymeric electrolyte based dye-sensitized solar cell with improved stability

NASA Astrophysics Data System (ADS)

Prasad, Narottam; Kumar, Manish; Patel, K. R.; Roy, M. S.

2018-05-01

The impact of polymeric electrolyte was investigated over the performance of dye-sensitized solar cell made with Rose Bengal as sensitizer. Further, the selective influence of TiCl4 treatment and pre-sensitizer deoxycholic acid on nc-TiO2 photoanode was determined in terms of improvement in conversion efficiency of the cell. It is found that the effect of TiCl4 treatment was comparatively more than pre-sensitization with de-oxy cholic acid towards improving the efficiency of the cell. The conversion efficiency on TiCl4 treatment was 0.2% whereas on pre-sensitization with deoxy chollic acid it was 0.1%. The combined effect of both TiCl4 treatment & pre-sensitization with deoxycholic acid leads conversion efficiency to 0.33%.

Development of portable mass spectrometer with electron cyclotron resonance ion source for detection of chemical warfare agents in air.

PubMed

Urabe, Tatsuya; Takahashi, Kazuya; Kitagawa, Michiko; Sato, Takafumi; Kondo, Tomohide; Enomoto, Shuichi; Kidera, Masanori; Seto, Yasuo

2014-01-01

A portable mass spectrometer with an electron cyclotron resonance ion source (miniECRIS-MS) was developed. It was used for in situ monitoring of trace amounts of chemical warfare agents (CWAs) in atmospheric air. Instrumental construction and parameters were optimized to realize a fast response, high sensitivity, and a small body size. Three types of CWAs, i.e., phosgene, mustard gas, and hydrogen cyanide were examined to check if the mass spectrometer was able to detect characteristic elements and atomic groups. From the results, it was found that CWAs were effectively ionized in the miniECRIS-MS, and their specific signals could be discerned over the background signals of air. In phosgene, the signals of the 35Cl+ and 37Cl+ ions were clearly observed with high dose-response relationships in the parts-per-billion level, which could lead to the quantitative on-site analysis of CWAs. A parts-per-million level of mustard gas, which was far lower than its lethal dosage (LCt50), was successfully detected with a high signal-stability of the plasma ion source. It was also found that the chemical forms of CWAs ionized in the plasma, i.e., monoatomic ions, fragment ions, and molecular ions, could be detected, thereby enabling the effective identification of the target CWAs. Despite the disadvantages associated with miniaturization, the overall performance (sensitivity and response time) of the miniECRIS-MS in detecting CWAs exceeded those of sector-type ECRIS-MS, showing its potential for on-site detection in the future. Copyright © 2013 Elsevier B.V. All rights reserved.

Modeled Martian subsurface elemental composition measurements with the Probing In situ with Neutron and Gamma ray instrument

NASA Astrophysics Data System (ADS)

Nowicki, Suzanne F.; Evans, Larry G.; Starr, Richard D.; Schweitzer, Jeffrey S.; Karunatillake, Suniti; McClanahan, Timothy P.; Moersch, Jeffrey E.; Parsons, Ann M.; Tate, Christopher G.

2017-02-01

The Probing In situ with Neutron and Gamma ray (PING) instrument is an innovative application of active neutron-induced gamma ray technology. The objective of PING is to measure the elemental composition of the Martian regolith. This manuscript presents PING's sensitivities as a function of the Martian regolith depth and PING's uncertainties in the measurements as a function of observation time in passive and active mode. The modeled sensitivities show that in PING's active mode, where both a pulsed neutron generator (PNG) and a gamma ray spectrometer (GRS) are used, PING can interrogate the material below the rover to about 20 cm due to the penetrating nature of the high-energy neutrons and the resulting secondary gamma rays observed with the GRS. PING is capable of identifying most major and minor rock-forming elements, including H, O, Na, Mn, Mg, Al, Si, P, S, Cl, Cr, K, Ca, Ti, Fe, and Th. The modeled uncertainties show that PING's use of a PNG reduces the required observation times by an order of magnitude over a passive operating mode where the PNG is turned off. While the active mode allows for more complete elemental inventories with higher sensitivity, the gamma ray signatures of some elements are strong enough to detect in passive mode. We show that PING can detect changes in key marker elements and make thermal neutron measurements in about 1 min that are sensitive to H and Cl.

Flow injection analysis of organic peroxide explosives using acid degradation and chemiluminescent detection of released hydrogen peroxide.

PubMed

Mahbub, Parvez; Zakaria, Philip; Guijt, Rosanne; Macka, Mirek; Dicinoski, Greg; Breadmore, Michael; Nesterenko, Pavel N

2015-10-01

The applicability of acid degradation of organic peroxides into hydrogen peroxide in a pneumatically driven flow injection system with chemiluminescence reaction with luminol and Cu(2+) as a catalyst (FIA-CL) was investigated for the fast and sensitive detection of organic peroxide explosives (OPEs). The target OPEs included hexamethylene triperoxide diamine (HMTD), triacetone triperoxide (TATP) and methylethyl ketone peroxide (MEKP). Under optimised conditions maximum degradations of 70% and 54% for TATP and HMTD, respectively were achieved at 162 µL min(-1), and 9% degradation for MEKP at 180 µL min(-1). Flow rates were precisely controlled in this single source pneumatic pressure driven multi-channel FIA system by model experiments on mixing of easily detectable component solutions. The linear range for detection of TATP, HMTD and H2O2 was 1-200 µM (r(2)=0.98-0.99) at both flow rates, while that for MEKP was 20-200 µM (r(2)=0.97) at 180 µL min(-1). The detection limits (LODs) obtained were 0.5 µM for TATP, HMTD and H2O2 and 10 µM for MEKP. The detection times varied from 1.5 to 3 min in this FIA-CL system. Whilst the LOD for H2O2 was comparable with those reported by other investigators, the LODs and analysis times for TATP and HMTD were superior, and significantly, this is the first time the detection of MEKP has been reported by FIA-CL. Copyright © 2015 Elsevier B.V. All rights reserved.

Physical and Chemical Microstructural Damage in Pressed CL-20 explosives

NASA Astrophysics Data System (ADS)

Demol, Gauthier; Sandusky, Harold W.

1999-06-01

Based upon its molecular composition, its structure, and its heat of formation, it was expected that CL-20 (hexanitrohexaazaisowurtzitane) would be more energetic and more sensitive than RDX and HMX. Reports of batch-to-batch variations in the sensitivity of neat CL-20 have led to its sensitivity being ranked in the range between the sensitivity of RDX and that of PETN. The ultimate utility of CL-20 as an ingredient in explosive and propellant formulations will depend upon the ability to understand the factors that are responsible for this batch-to-batch variability, and to control the sensitivity in formulations within acceptable limits. This work is a characterization of CL-20 at various stages in its life cycle. The evolution of damage from the initial neat crystals of CL-20 to the ready-to-use pressed pellets will be described. This characterization includes physical documentation using light microscopy and Scanning Electron Microscopy. Spatially resolved chemical analysis is also performed using Fourier-Transform Infrared Spectroscopy.

Au-Pt-Au nanoraspberry structures used for mercury ion detection

NASA Astrophysics Data System (ADS)

Huang, Jiang-Hao; Huang, Shuai; Wen, Xiaoyan; Li, Min; Lu, Haifei

2017-12-01

Detection of Hg2+ with high sensitivity is of great significance in the biochemical sensing field. Quantitative of Hg2+ was realized based on the influence of Hg2+ on the UV-vis absorption performance of Au-Pt-Au core-shell nanoraspberry (APA)-rhodamine-6G (R6G) structure. First, APA sol was added into R6G indicator solution and the UV-vis absorption signal intensity of R6G was evidently promoted. The signal intensity monotonously increased as more APA sol was added. However, when HgCl2 solution was introduced, the signal intensity declined. A linear relationship between Hg2+ concentration and signal intensity at 527 nm was revealed, based on which quantitative determination of Hg2+ could be realized. Hg2+ detection sensitivity was measured to be 0.031 a.u./M with a limit of detection of 10-7 M and the response time was 20 s. A high Hg2+ detection selectivity over Cu2+, Na+, Li+, and K+ was demonstrated. Due to its simplicity and high sensitivity, the proposed method could find an extensive application prospect in the Hg2+ detection field.

Application of direct-injection detector integrated with the multi-pumping flow system to chemiluminescence determination of the total polyphenol index.

PubMed

Nalewajko-Sieliwoniuk, Edyta; Iwanowicz, Magdalena; Kalinowski, Sławomir; Kojło, Anatol

2016-03-10

In this work, we present a novel chemiluminescence (CL) method based on direct-injection detector (DID) integrated with the multi-pumping flow system (MPFS) to chemiluminescence determination of the total polyphenol index. In this flow system, the sample and the reagents are injected directly into the cone-shaped detection cell placed in front of the photomultiplier window. Such construction of the detection chamber allows for fast measurement of the CL signal in stopped-flow conditions immediately after mixing the reagents. The proposed DID-CL-MPFS method is based on the chemiluminescence of nanocolloidal manganese(IV)-hexametaphosphate-ethanol system. The application of ethanol as a sensitizer, eliminated the use of carcinogenic formaldehyde. Under the optimized experimental conditions, the chemiluminescence intensities are proportional to the concentration of gallic acid in the range from 5 to 350 ng mL(-1). The DID-CL-MPFS method offers a number of advantages, including low limit of detection (0.80 ng mL(-1)), high precision (RSD = 3.3%) and high sample throughput (144 samples h(-1)) as well as low consumption of reagents, energy and low waste generation. The proposed method has been successfully applied to determine the total polyphenol index (expressed as gallic acid equivalent) in a variety of plant-derived food samples (wine, tea, coffee, fruit and vegetable juices, herbs, spices). Copyright © 2016 Elsevier B.V. All rights reserved.

Bubble electrodeposition of gold porous nanocorals for the enzymatic and non-enzymatic detection of glucose.

PubMed

Sanzó, Gabriella; Taurino, Irene; Antiochia, Riccarda; Gorton, Lo; Favero, Gabriele; Mazzei, Franco; De Micheli, Giovanni; Carrara, Sandro

2016-12-01

Au nanocorals are grown on gold screen-printed electrodes (SPEs) by using a novel and simple one-step electrodeposition process. Scanning electron microscopy was used for the morphological characterization. The devices were assembled on a three-electrode SPE system, which is flexible and mass producible. The electroactive surface area, determined by cyclic voltammetry in sulphuric acid, was found to be 0.07±0.01cm(2) and 35.3±2.7cm(2) for bare Au and nanocoral Au, respectively. The nanocoral modified SPEs were used to develop an enzymatic glucose biosensor based on H2O2 detection. Au nanocoral electrodes showed a higher sensitivity of 48.3±0.9μA/(mMcm(2)) at +0.45V vs Ag|AgCl compared to a value of 24.6±1.3μA/(mMcm(2)) at +0.70V vs Ag|AgCl obtained with bare Au electrodes. However, the modified electrodes have indeed proven to be extremely powerful for the direct detection of glucose with a non-enzymatic approach. The results confirmed a clear peak observed by using nanocoral Au electrode even in the presence of chloride ions at physiological concentration. Amperometric study carried out at +0.15V vs Ag|AgCl in the presence of 0.12M NaCl showed a linear range for glucose between 0.1 and 13mM. Copyright © 2016. Published by Elsevier B.V.

Determination of the pseudoephedrine content in pharmaceutical formulations and in biological fluids using a microbore HPLC system interfaced to a microfluidic chemiluminescence detector.

PubMed

Kadavilpparampu, Afsal Mohammed; Al-Lawati, Haider A J; Suliman, FakhrEldin O; Al Kindy, Salma M Z

2015-12-01

A novel automated precolumn derivatization followed by separation using liquid chromatography for the determination of pseudoephedrine (PSE) by a microfluidic chemiluminescence detector has been developed. An on-line derivatization procedure was utilized by converting PSE into a highly light emitting species in a Ru(bipy)3(2+)-peroxydisulphate chemiluminescence (CL) system by derivatizing it with a 1.0 M formaldehyde solution. The derivatized analyte was directly injected into a microbore high-performance liquid chromatography (HPLC) system coupled to an on-chip chemiluminescence detector. The newly developed highly selective, sensitive and fast HPLC-CL method was validated and successfully applied for the analysis of PSE in pharmaceutical formulations and a human urine sample. The selectivity of the method is not only due to the HPLC separation but is also due to the highly selective detection principle of the Ru(bipy)3(2+)-peroxydisulphate CL system used. There was no interference observed from the common preservatives and excipients used in pharmaceutical preparations, which did not show any significant CL signal. The retention time of PSE was less than 3 min, and the detection limits and quantification limits were found to be 5.7 and 26.0 µg L(-1), respectively. Copyright © 2015 John Wiley & Sons, Ltd.

Molecular Epidemiological Survey of Cutaneous Leishmaniasis in Two Highly Endemic Metropolises of Iran, Application of FTA Cards for DNA Extraction From Giemsa-Stained Slides

PubMed Central

Izadi, Shahrokh; Mirhendi, Hossein; Jalalizand, Niloufar; Khodadadi, Hossein; Mohebali, Mehdi; Nekoeian, Shahram; Jamshidi, Ali; Ghatee, Mohammad Amin

2016-01-01

Background: PCR has been used for confirmation of leishmaniasis in epidemiological studies, but complexity of DNA extraction and PCR approach has confined its routine use in developing countries. Objectives: In this study, recent epidemiological situation of cutaneous leishmaniasis (CL) in two hyper-endemic metropolises of Shiraz and Isfahan in Iran was studied using DNA extraction by commercial FTA cards and kinetoplastid DNA (kDNA)-PCR amplification for detection/identification of Leishmania directly from stained skin scraping imprints. Patients and Methods: Fifty four and 30 samples were collected from clinically diagnosed CL patients referred to clinical laboratories of leishmaniasis control centers in Isfahan and Shiraz cities, respectively. The samples were examined by direct microscopy and then scrapings of the stained smears were applied to FTA cards and used directly as DNA source in a nested-PCR to amplify kDNA to detect and identify Leishmania species. Results: Fifty four of 84 (64.2%) slides obtained from patients had positive results microscopically, while 79/84 (94%) of slides had positive results by FTA card-nested-PCR. PCR and microscopy showed a sensitivity of 96.4% and 64.2% and specificity of 100% and 100%, respectively. Interestingly, Leishmania major as causative agent of zoonotic CL was identified in 100% and 90.7% of CL cases from Isfahan and Shiraz cities, respectively, but L. tropica was detected from only 9.3% of cases from Shiraz city. All cases from central regions of Shiraz were L. tropica and no CL case was found in Isfahan central areas. Conclusions: Filter paper-based DNA extraction can facilitate routine use of PCR for diagnosis of CL in research and diagnostic laboratories in Iran and countries with similar conditions. Epidemiologic changes including dominancy of L. major in suburbs of Shiraz and Isfahan metropolises where anthroponotic CL caused by L. tropica had been established, showed necessity of precise studies on CL epidemiology in old urban and newly added districts in the suburbs. PMID:27127596

Colorimetric detection of Cucumber green mottle mosaic virus using unmodified gold nanoparticles as colorimetric probes.

PubMed

Wang, Lin; Liu, Zhanmin; Xia, Xueying; Yang, Cuiyun; Huang, Junyi; Wan, Sibao

2017-05-01

Cucumber green mottle mosaic virus (CGMMV)causes a severe mosaic symptom of watermelon and cucumber, and can be transmitted via infected cucumber seeds, leaves and soil. It remains a challenge to detect this virus to prevent its introduction and infection and spread in fields. For this purpose, a simple and sensitive label-free colorimetric detection method for CGMMV has been developed with unmodified gold nanoparticles (AuNPs) as colorimetric probes. The method is based on the finding that the presence of RT-PCR target products of CGMMV and species-specific probes results in color change of AuNPs from red to blue after NaCl induction. Normally, species-specific probes attach to the surface of AuNPs and thereby increasing their resistance to NaCl-induced aggregation. The concentration of sodium, probes in the reaction system and evaluation of specificity and sensitivity of a novel assay, visual detection of Cucumber green mottle mosaic virus using unmodified AuNPs has been carried out with simple preparation of samples in our study. Through this assay, as low as 30pg/μL of CGMMV RNA was thus detected visually, by the naked eye, without the need for any sophisticated, expensive instrumentation and biochemical reagents. The specificity was 100% and exhibited good reproducibility in our assays. The results note that this assay is highly species-specific, simple, low-cost, and visual for easy detection of CGMMV in plant tissues. Therefore, visual assay is a potentially useful tool for middle or small-scales corporations and entry-exit inspection and quarantine bureau to detect CGMMV in cucumber seeds or plant tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of Sulfonamide Residues in Food by Capillary Zone Electrophoresis with On-Line Chemiluminescence Detection Based on an Ag(III) Complex.

PubMed

Dai, Tingting; Duan, Jie; Li, Xinghua; Xu, Xiangdong; Shi, Hongmei; Kang, Weijun

2017-06-16

The presence of sulfonamide (SA) residues in foods is largely due to the raising of animals with sulfonamide antibiotics added or polluted feedstuff. In this paper, a sensitive method was developed for the determination of the residues of three sulfonamides in animal-derived food; the SAs include sulfadimidine (SDD), sulfadiazine (SDZ), and sulfathiazole (STZ). The method is based on capillary zone electrophoresis (CE) with online chemiluminescence (CL) detection, using an Ag(III) complex as an oxidant. These SAs have an inhibiting effect on the Ag(III)-luminol CL reaction. The electrophoretic buffer is 12.0 mM sodium borate. Under a set of optimized conditions, the linear ranges for the detections were found to be 10.0-200 µg·mL -1 for SDD and SDZ, and 2.0-50.0 µg·mL -1 for STZ. The detection limits were 2.75, 3.14, and 0.65 µg·mL -1 for SDD, SDZ, and STZ, respectively. Relative standard deviations (RSD) for the peak heights were between 2.1% and 2.8% (n = 7). The proposed method was used in the analysis of the SAs in samples from pork meat, chicken meat, and milk, showing satisfactory detection results. A reaction mechanism was also proposed for the Ag(III)-luminol-SA CL reactions. The method has potential applications for the monitoring of residue levels of the three SAs in food, providing food safety data.

[The construction of cell-penetrating peptide R8 and pH sensitive cleavable polyethylene glycols co-modified liposomes].

PubMed

Zhang, Li; Wang, Yang; Gao, Hui-le; He, Qin

2015-06-01

The purpose of the study is to construct R8 peptide (RRRRRRRR) and pH sensitive polyethylene glycols (PEG) co-modified liposomes (Cl-Lip) and utilize them in breast cancer treatment. The co-modified liposomes were prepared with soybean phospholipid, cholesterol, DSPE-PEG2K-R8 and PEG5K-Hz-PE (pH sensitive PEG). The size and zeta potential of Cl-Lip were also characterized. The in vitro experiment demonstrated that the Cl-Lip had high serum stability in 50% fetal bovine serum. The cellular uptake of Cl-Lip under different pre-incubated conditions was evaluated on 4T1 cells. And the endocytosis pathway, lysosome escape ability and tumor spheroid penetration ability were also evaluated. The results showed the particle size of the Cl-Lip was (110.4 ± 5.2) nm, PDI of the Cl-Lip was 0.207 ± 0.039 and zeta potential of the Cl-Lip was (-3.46 ± 0.05) mV. The cellular uptake of Cl-Lip on 4T1 cells was pH sensitive, as the cellular uptake of Cl-Lip pre-incubated in pH 6.0 was higher than that of pH 7.4 under each time point. The main endocytosis pathways of Cl-Lip under pH 6.0 were micropinocytosis and energy-dependent pathway. At the same time, the Cl-Lip with pre-incubation in pH 6.0 had high lysosome escape ability and high tumor spheroid penetration ability. All the above results demonstrated that the Cl-Lip we constructed had high pH sensitivity and is a promising drug delivery system.

Application of cetylpyridinium chloride and sodium chloride decontamination method for recovery of Mycobacterium tuberculosis from clinically suspected cases of pulmonary tuberculosis.

PubMed

Shinu, Pottathil; Singh, Varsha; Nair, Anroop; Mehrishi, Priya; Mehta, Sonia; Joshi, Ekta

2013-10-01

The study was designed to compare the efficacy of cetylpyridinium chloride (CPC) and sodium chloride (NaCl) decontamination method with N-acetyl L-Cystine (NALC) and sodium hydroxide (NaOH) decontamination (the reference method) method for the recovery of Mycobacterium tuberculosis (MTB) from clinically suspected cases of pulmonary tuberculosis. To evaluate CPC-NaCl and NALC-NaOH decontamination methods, sputum specimens (n = 796) were studied (culturing on Löwenstein-Jensen medium), and the performances were compared. The CPC-NaCl decontamination method demonstrated a sensitivity, specificity, negative predictive value, and positive predictive value of 97.99%, 87.53%, 70.19%, and 99.32%, respectively, when compared to NALC-NaOH decontamination method. In summary, CPC-NaCl decontamination method effectively detected significantly higher number of MTB cases (n = 208) than NALC-NaOH decontamination method (n = 149) particularly in sputum with scanty bacilli and smear-negative cases, indicating the potential of CPC-NaCl decontamination method to preserve paucibacillary cases more efficient than NALC-NaOH decontamination method. © 2013.

Flow-injection chemiluminescence determination of ofloxacin and levofloxacin in pharmaceutical preparations and biological fluids.

PubMed

Sun, Hanwen; Li, Liqing; Chen, Xueyan

2006-08-01

A novel, rapid and sensitive analytical method is described for determination of ofloxacin and levofloxacin by enhanced chemiluminescence (CL) with flow-injection sampling. The method is based on the CL reaction of the Ce(IV)-Na2S2O4-ofloxacin/levofloxacin-H2SO2 system. The enhanced CL mechanism was developed and the optimum conditions for CL emission were investigated. The CL intensity was correlated linearly (r = 0.9988) with the concentration of ofloxacin (or levofloxacin) in the range of 1.0 x 10(-8) - 1.0 x 10(-7) g ml(-1) and 1.0 x 10(-7) - 6.0 x 10(-6) g ml(-1). The detection limit (S/N = 3) is 7 x 10(-9) g ml(-1). The relative standard derivation (RSD, n = 11) is 2.0% for ofloxacin at 4 x 10(-7) g ml(-1) and for levofloxacin at 6 x 10(-7) g ml(-1). This method has been successfully applied for the determination of ofloxacin and levofloxacin in pharmaceutical preparations and biological fluids with satisfactory results.

An improved glycerol biosensor with an Au-FeS-NAD-glycerol-dehydrogenase anode.

PubMed

Mahadevan, Aishwarya; Fernando, Sandun

2017-06-15

An improved glycerol biosensor was developed via direct attachment of NAD + -glycerol dehydrogenase coenzyme-apoenzyme complex onto supporting gold electrodes, using novel inorganic iron (II) sulfide (FeS)-based single molecular wires. Sensing performance factors, i.e., sensitivity, a detection limit and response time of the FeS and conventional pyrroloquinoline quinone (PQQ)-based biosensor were evaluated by dynamic constant potential amperometry at 1.3V under non-buffered conditions. For glycerol concentrations ranging from 1 to 25mM, a 77% increase in sensitivity and a 53% decrease in detection limit were observed for the FeS-based biosensor when compared to the conventional PQQ-based counterpart. The electrochemical behavior of the FeS-based glycerol biosensor was analyzed at different concentrations of glycerol, accompanied by an investigation into the effects of applied potential and scan rate on the current response. Effects of enzyme stimulants ((NH 4 ) 2 SO 4 and MnCl 2 ·4H 2 O) concentrations and buffers/pH (potassium phosphate buffer pH 6-8, Tris buffer pH 8-10) on the current responses generated by the FeS-based glycerol biosensor were also studied. The optimal detection conditions were 0.03M (NH 4 ) 2 SO 4 and 0.3µm MnCl 2 ·4H 2 O in non-buffered aqueous electrolyte under stirring whereas under non-stirring, Tris buffer at pH 10 with 0.03M (NH 4 ) 2 SO 4 and 30µm MnCl 2 ·4H 2 O were found to be optimal detection conditions. Interference by glucose, fructose, ethanol, and acetic acid in glycerol detection was studied. The observations indicated a promising enhancement in glycerol detection using the novel FeS-based glycerol sensing electrode compared to the conventional PQQ-based one. These findings support the premise that FeS-based bioanodes are capable of biosensing glycerol successfully and may be applicable for other enzymatic biosensors. Copyright © 2016 Elsevier B.V. All rights reserved.

Highly sensitive detection of multiple tumor markers for lung cancer using gold nanoparticle probes and microarrays.

PubMed

Gao, Wanlei; Wang, Wentao; Yao, Shihua; Wu, Shan; Zhang, Honglian; Zhang, Jishen; Jing, Fengxiang; Mao, Hongju; Jin, Qinghui; Cong, Hui; Jia, Chunping; Zhang, Guojun; Zhao, Jianlong

2017-03-15

Assay of multiple serum tumor markers such as carcinoembryonic antigen (CEA), cytokeratin 19 fragment antigen (CYFRA21-1), and neuron specific enolase (NSE), is important for the early diagnosis of lung cancer. Dickkopf-1 (DKK1), a novel serological and histochemical biomarker, was recently reported to be preferentially expressed in lung cancer. Four target proteins were sandwiched by capture antibodies attached to microarrays and detection antibodies carried on modified gold nanoparticles. Optical signals generated by the sandwich structures were amplified by gold deposition with HAuCl 4 and H 2 O 2 , and were observable by microscopy or the naked eye. The four tumor markers were subsequently measured in 106 lung cancer patients and 42 healthy persons. The assay was capable of detecting multiple biomarkers in serum sample at concentration of <1 ng mL -1 in 1 h. Combined detection of the four tumor markers highly improved the sensitivity (to 87.74%) for diagnosis of lung cancer compared with sensitivity of single markers. A rapid, highly sensitive co-detection method for multiple biomarkers based on gold nanoparticles and microarrays was developed. In clinical use, it would be expected to improve the early diagnosis of lung cancer. Copyright © 2016 Elsevier B.V. All rights reserved.

Label-free SERS study of galvanic replacement reaction on silver nanorod surface and its application to detect trace mercury ion

PubMed Central

Wang, Yaohui; Wen, Guiqing; Ye, Lingling; Liang, Aihui; Jiang, Zhiliang

2016-01-01

It is significant to explore a rapid and highly sensitive galvanic replacement reaction (GRR) surface enhanced Raman scattering (SERS) method for detection of trace mercury ions. This article was reported a new GRR SERS analytical platform for detecting Hg(II) with label-free molecular probe Victoria blue B (VBB). In HAc-NaCl-silver nanorod (AgNR) substrate, the molecular probe VBB exhibited a strong SERS peak at 1609 cm−1. Upon addition of Hg(II), the GRR occurred between the AgNR and Hg(II), and formed a weak SERS activity of Hg2Cl2 that deposited on the AgNR surfaces to decrease the SERS intensity at 1609 cm−1. The decreased SERS intensity was linear to Hg(II) concentration in the range of 1.25–125 nmol/L, with a detection limit of 0.2 nmol/L. The GRR was studied by SERS, transmission electron microscopy and other techniques, and the GRR mechanism was discussed. PMID:26792071

Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells.

PubMed

Valinsky, William C; Touyz, Rhian M; Shrier, Alvin

2017-08-01

Thiazides block Na + reabsorption while enhancing Ca 2+ reabsorption in the kidney. As previously demonstrated in immortalized mouse distal convoluted tubule (MDCT) cells, chlorothiazide application induced a robust plasma membrane hyperpolarization, which increased Ca 2+ uptake. This essential thiazide-induced hyperpolarization was prevented by the Cl - channel inhibitor 5-Nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), implicating NPPB-sensitive Cl - channels, however the nature of these Cl - channels has been rarely described in the literature. Here we show that MDCT cells express a dominant, outwardly rectifying Cl - current at extracellular pH7.4. This constitutive Cl - current was more permeable to larger anions (Eisenman sequence I; I - >Br - ≥Cl - ) and was substantially inhibited by >100mM [Ca 2+ ] o , which distinguished it from ClC-K2/barttin. Moreover, the constitutive Cl - current was blocked by NPPB, along with other Cl - channel inhibitors (4,4'-diisothiocyanatostilbene-2,2'-disulfonate, DIDS; flufenamic acid, FFA). Subjecting the MDCT cells to an acidic extracellular solution (pH<5.5) induced a substantially larger outwardly rectifying NPPB-sensitive Cl - current. This acid-induced Cl - current was also anion permeable (I - >Br - >Cl - ), but was distinguished from the constitutive Cl - current by its rectification characteristics, ion sensitivities, and response to FFA. In addition, we have identified similar outwardly rectifying and acid-sensitive currents in immortalized cells from the inner medullary collecting duct (mIMCD-3 cells). Expression of an acid-induced Cl - current would be particularly relevant in the acidic IMCD (pH<5.5). To our knowledge, the properties of these Cl - currents are unique and provide the mechanisms to account for the Cl - efflux previously speculated to be present in MDCT cells. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

A nanoscale Zr-based fluorescent metal-organic framework for selective and sensitive detection of hydrogen sulfide

NASA Astrophysics Data System (ADS)

Li, Yanping; Zhang, Xin; Zhang, Ling; Jiang, Ke; Cui, Yuanjing; Yang, Yu; Qian, Guodong

2017-11-01

Hydrogen sulfide (H2S) has been commonly viewed as a gas signaling molecule in various physiological and pathological processes. However, the highly efficient H2S detection still remains challenging. Herein, we designed a new robust nano metal-organic framework (MOF) UiO-66-CH=CH2 as a fluorescent probe for rapid, sensitive and selective detection of biological H2S. UiO-66-CH=CH2 was prepared by heating ZrCl4 and 2-vinylterephthalic acid via a simple method. UiO-66-CH=CH2 displayed fluorescence quenching to H2S and kept excellent selectivity in the presence of biological relevant analytes especially the cysteine and glutathione. This MOF-based probe also exhibited fast response (10 s) and high sensitivity with a detection limit of 6.46 μM which was within the concentration range of biological H2S in living system. Moreover, this constructed MOF featured water-stability, nanoscale (20-30 nm) and low toxicity, which made it a promising candidate for biological H2S sensing.

Graphene oxide-coated stir bar sorptive extraction of trace aflatoxins from soy milk followed by high performance liquid chromatography-laser-induced fluorescence detection.

PubMed

Ma, Haiyan; Ran, Congcong; Li, Mengjiao; Gao, Jinglin; Wang, Xinyu; Zhang, Lina; Bian, Jing; Li, Junmei; Jiang, Ye

2018-04-01

Mycotoxins are potential food pollutants produced by fungi. Among them, aflatoxins (AFs) are the most toxic. Therefore, AFs were selected as models, and a sensitive, simple and green graphene oxide (GO)-based stir bar sorptive extraction (SBSE) method was developed for extraction and determination of AFs with high performance liquid chromatography-laser-induced fluorescence detector (HPLC-LIF). This method improved the sensitivity of AFs detection and solved the deposition difficulty of the direct use of GO as adsorbent. Several parameters including a spiked amount of NaCl, stirring rate, extraction time and desorption time were investigated. Under optimal conditions, the quantitative method had low limits of detection of 2.4-8.0 pg/mL, which were better than some reported AFs analytical methods. The developed method has been applied to soy milk samples with good recoveries ranging from 80.5 to 102.3%. The prepared GO-based SBSE can be used as a sensitive screening technique for detecting AFs in soy milk.

Immunoblotting assays for keratan sulfate.

PubMed

Yoon, Jung Hae; Brooks, Randolph; Halper, Jaroslava

2002-07-15

The detection of microquantities of glycosaminoglycans (GAGs) in biological samples has been hampered by the lack of sensitive methods. In this paper we describe the modification and development of three sensitive assays capable of detecting nanogram quantities of GAGs in biological samples. The first assay detects total GAGs. It is a modified Alcian blue dye precipitation assay in which the dye binds to the negatively charged GAGs in CsCl-fractionated extracts from chicken tendons. This assay compares favorably with the widely used uronic acid assay in terms of its sensitivity and ability to detect all classes of GAGs, including keratan sulfate (KS). Two other assays, dot-blotting and immunoblotting, detect KS in complex mixtures and can be easily adapted for the detection of other GAGs. Both take advantage of binding of carboxyl and sulfate groups of GAGs to trivalent neodymium. In dot-blotting, samples were directly blotted onto nitrocellulose membrane soaked in Nd(2)(SO(4))(3) buffer, and KS was detected with the monoclonal anti-KS 5-D-4 antibody and an avidin-biotin complex detection system. In immunoblotting, the samples were first separated in 28% polyacrylamide gels, transferred onto a Nd(2)(SO(4))(3)-soaked nitrocellulose membrane using a phosphate buffer system, and stained and developed using the same protocol as in dot-blotting. Whereas dot-blotting allows the use of very low quantities of samples because of its high sensitivity (lower detection limit was 5 ng), immunoblotting provides more specificity.

Aspects of Salt Tolerance in a NaCl-Selected Stable Cell Line of Citrus sinensis.

PubMed

Ben-Hayyim, G; Kochba, J

1983-07-01

A NaCl-tolerant cell line which was selected from ovular callus of ;Shamouti' orange (Citrus sinensis L. Osbeck) proved to be a true cell line variant. This conclusion is based on the following observations. (a) Cells which have been removed from the selection pressure for at least four passages retain the same NaCl tolerance as do cells which are kept constantly on 0.2 molar NaCl. (b) Na(+) and Cl(-) uptake are considerably lower in salt-tolerant cells (R-10) than in salt-sensitive cells (L-5) at a given external NaCl concentration. (c) Growth of salt-tolerant cells is markedly suppressed upon replacement of NaCl by KCl, whereas the growth of salt-sensitive cells is only slightly affected. Accumulation of K(+) and Cl(-) accompanies the inhibition of growth. Experiments carried out with sodium and potassium sulfate suggest that the toxic effect is due to the accumulated Cl(-). (d) Removal of Ca(2+) from the growth medium severely inhibits the growth of salt-tolerant cells in the presence of NaCl, while it has a minor effect on growth of salt-sensitive cells in the presence of NaCl. (e) Electron micrographs show that the salt-tolerant cells have very big vacuoles when exposed to salt, while the size of the vacuoles of the salt-sensitive cells does not change.

Evaluation of neuraminidase enzyme assays using different substrates to measure susceptibility of influenza virus clinical isolates to neuraminidase inhibitors: report of the neuraminidase inhibitor susceptibility network.

PubMed

Wetherall, N T; Trivedi, T; Zeller, J; Hodges-Savola, C; McKimm-Breschkin, J L; Zambon, M; Hayden, F G

2003-02-01

The increasing use of influenza virus neuraminidase (NA) inhibitors (NIs) necessitates the development of reliable methods for assessing the NI susceptibility of clinical isolates. We evaluated three NA inhibition assays against a panel of five clinical isolates each of influenza virus A/H1N1, A/H3N2, and B strains and four viruses with a defined resistance genotype (R292K, H274Y, R152K, and E119V). For fluorometric enzyme assay (FA) 1 (FA-1), 2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid (MUNANA) at 100 microM was used as the substrate, with pretitration of the virus input. For FA-2, MUNANA at 200 microM was used as the substrate, with a fixed 1:10 dilution of input virus. For the chemiluminescence (CL) assay, the 1,2-dioxetane derivative of sialic acid at 100 microM was used as the substrate, with pretitration of the virus. Four different operators repeated the assays several times in a blinded fashion with both zanamivir and oseltamivir carboxylate (GS4071) to determine intra- and interassay variations. Mean 50% inhibitory concentration (IC(50)) values were lower and generally less variable with the CL assay. FA-1 displayed greater variation than the CL assay or FA-2 and the highest IC(50) values with zanamivir; FA-2 showed the highest values with oseltamivir, particularly for influenza virus B, and was more variable with zanamivir than was the CL assay. All three assays detected 40-fold or greater changes in IC(50) values for the resistant viruses with at least one drug. Mixing experiments, whereby increasing fractions (0, 20, 40, 60, 80, and 100%) of NA from a known NI-resistant virus were mixed with the corresponding NI-sensitive parental NA, indicated that the resolution of IC(50) values was clearer with the CL assay than with FA-2 for two of the resistant variants (R152K and E119V). The FA and CL methods were reliable for the detection of NI resistance, but all assays have certain limitations. Based on reproducibility, ease of automation, time required for the assay, and greater sensitivity, the CL assay was selected for future susceptibility testing of influenza virus isolates circulating globally.

Simultaneous determination of five synthetic pyrethroid metabolites in urine by liquid chromatography-tandem mass spectrometry: application to 39 persons without known exposure to pyrethroids.

PubMed

Le Grand, R; Dulaurent, S; Gaulier, J M; Saint-Marcoux, F; Moesch, C; Lachâtre, G

2012-04-25

A sensitive and reliable method was developed and validated for the determination of five synthetic pyrethroid metabolites namely cis-Cl(2)CA, trans-Cl(2)CA, Br(2)CA, 3-PBA and 4-FPBA in human urine by liquid chromatography-tandem mass spectrometry. (2)D(6)-labelled trans-Cl(2)CA and (13)C(6)-labelled 3-PBA were used as internal standards. This method was based on a liquid-liquid extraction procedure in acidic conditions using hexane solvent with a basic purification, a chromatographic separation using a specific C18 column and mass spectrometric detection in the negative polarity. Suitable limits of detection (0.015μg/L for the five compounds) and quantification (from 0.020 to 0.030μg/L) were obtained for rendering the method usable for the biomonitoring of pyrethroids in the general population. The efficiency of the method was tested in 39 urine samples from French people without any known exposure to pyrethroids. At least three of the five metabolites were detected in each sample. The results of this study were compared to those obtained in previous ones and discussed. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Determination of ethanol using permanganate-CdS quantum dot chemiluminescence system.

PubMed

Abolhasani, Jafar; Hassanzadeh, Javad

2015-08-01

A novel and highly sensitive chemiluminescence (CL) method for the determination of ethanol was developed based on the CdS quantum dots (QDs)-permanganate system. It was found that KMnO4 could directly oxidize CdS QDs in acidic media resulting in relatively high CL emission. A possible mechanism was proposed for this reaction based on UV/Vis absorption, fluorescence and the generated CL emission spectra. However, it was observed that ethanol had a remarkable inhibition effect on this system. This effect was exploited in the determination of ethanol within the concentration range 12-300 µg/L, with detection at 4.3 µg/L. In order to evaluate the capability of presented method, it was satisfactorily utilized in the determination of alcohol in real samples. Copyright © 2014 John Wiley & Sons, Ltd.

Reduced DIDS-sensitive chloride conductance in Ae1-/- mouse erythrocytes

PubMed Central

Alper, Seth L.; Vandorpe, David H.; Peters, Luanne L.; Brugnara, Carlo

2008-01-01

The resting membrane potential of the human erythrocyte is largely determined by a constitutive Cl- conductance ∼100-fold greater than the resting cation conductance. The 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS)-sensitive electroneutral Cl- transport mediated by the human erythroid Cl-/HCO3- exchanger, AE1 (SLC4A1, band 3) is ≥10,000-fold greater than can be accounted for by the Cl- conductance of the red cell. The molecular identities of conductive anion pathways across the red cell membrane remain poorly defined. We have examined red cell Cl- conductance in the Ae1-/- mouse as a genetic test of the hypothesis that Ae1 mediates DIDS-sensitive Cl- conductance in mouse red cells. We report here that wildtype mouse red cell membrane potential resembles that of human red cells in the predominance of its Cl- conductance. We show with four technical approaches that the DIDS-sensitive component of erythroid Cl- conductance is reduced or absent from Ae1-/- red cells. These results are consistent with the hypothesis that the Ae1 anion exchanger polypeptide can operate infrequently in a conductive mode. However, the fragile red cell membrane of the Ae1-/- mouse red cell exhibits reduced abundance or loss of multiple polypeptides. Thus, loss of one or more distinct, DIDS-sensitive anion channel polypeptide(s) from the Ae1-/- red cell membrane cannot be ruled out as an explanation for the reduced DIDS-sensitive anion conductance. PMID:18329299

Flow injection chemiluminescence determination of naphazoline hydrochloride in pharmaceuticals.

PubMed

Iranifam, Mortaza; Sorouraddin, Mohammad H

2014-02-01

A simple and sensitive flow injection chemiluminescence (FI-CL) method was developed for the determination of naphazoline hydrochloride (NPZ). The method is based on the enhancing effect of NPZ on the weak CL signal from the reaction of KIO4 with H2 O2 . Experimental parameters that affected the CL signal, including the pH of the KIO4 solution, concentrations of KIO4 , H2 O2 and disodium-EDTA and flow rate were optimized. Under the optimum conditions, the increment of CL intensity was linearly proportional to the concentration of NPZ in the range 5.0 × 10(-6) to 70 × 10(-6) mol/L. The detection limit was 1.0 × 10(-6) mol/L and the relative standard deviation for 50 × 10(-6) mol/L NPZ solution was 2.8% (n = 11). In addition, a high throughput of 120 samples/h was achieved. The utility of this method was demonstrated by determining NPZ in pharmaceuticals. Copyright © 2013 John Wiley & Sons, Ltd.

TCSPC based approaches for multiparameter detection in living cells

NASA Astrophysics Data System (ADS)

Jahn, Karolina; Buschmann, Volker; Koberling, Felix; Hille, Carsten

2014-03-01

In living cells a manifold of processes take place simultaneously. This implies a precise regulation of intracellular ion homeostasis. In order to understand their spatio-temporal pattern comprehensively, the development of multiplexing concepts is essential. Due to the multidimensional characteristics of fluorescence dyes (absorption and emission spectra, decay time, anisotropy), the highly sensitive and non-invasive fluorescence microscopy is a versatile tool for realising multiplexing concepts. A prerequisite are analyte-specific fluorescence dyes with low cross-sensitivity to other dyes and analytes, respectively. Here, two approaches for multiparameter detection in living cells are presented. Insect salivary glands are well characterised secretory active tissues which were used as model systems to evaluate multiplexing concepts. Salivary glands secrete a KCl-rich or NaCl-rich fluid upon stimulation which is mainly regulated by intracellular Ca2+ as second messenger. Thus, pairwise detection of intracellular Na+, Cl- and Ca2+ with the fluorescent dyes ANG2, MQAE and ACR were tested. Therefore, the dyes were excited simultaneously (2-photon excitation) and their corresponding fluorescence decay times were recorded within two spectral ranges using time-correlated singlephoton counting (TCSPC). A second approach presented here is based on a new TCSPC-platform covering decay time detection from picoseconds to milliseconds. Thereby, nanosecond decaying cellular fluorescence and microsecond decaying phosphorescence of Ruthenium-complexes, which is quenched by oxygen, were recorded simultaneously. In both cases changes in luminescence decay times can be linked to changes in analyte concentrations. In consequence of simultaneous excitation as well as detection, it is possible to get a deeper insight into spatio-temporal pattern in living tissues.

The genetic control of contact sensitization to inorganic metal compounds in guinea-pigs

PubMed Central

Polák, L.; Barnes, J. M.; Turk, J. L.

1968-01-01

Only a proportion of outbred guinea-pigs can be sensitized to K2Cr2O7, BeF2 and HgCl2. Inbred Strain II can be sensitized to K2Cr2O7 and BeF2, but not to HgCl2. Inbred strain XIII can be sensitized to HgCl2 but not to K2Cr2O7 or BeF2. The ability to become sensitized appears to be transmitted as a dominant characteristic which is not sex linked. PMID:5656877

CLMSVault: A Software Suite for Protein Cross-Linking Mass-Spectrometry Data Analysis and Visualization.

PubMed

Courcelles, Mathieu; Coulombe-Huntington, Jasmin; Cossette, Émilie; Gingras, Anne-Claude; Thibault, Pierre; Tyers, Mike

2017-07-07

Protein cross-linking mass spectrometry (CL-MS) enables the sensitive detection of protein interactions and the inference of protein complex topology. The detection of chemical cross-links between protein residues can identify intra- and interprotein contact sites or provide physical constraints for molecular modeling of protein structure. Recent innovations in cross-linker design, sample preparation, mass spectrometry, and software tools have significantly improved CL-MS approaches. Although a number of algorithms now exist for the identification of cross-linked peptides from mass spectral data, a dearth of user-friendly analysis tools represent a practical bottleneck to the broad adoption of the approach. To facilitate the analysis of CL-MS data, we developed CLMSVault, a software suite designed to leverage existing CL-MS algorithms and provide intuitive and flexible tools for cross-platform data interpretation. CLMSVault stores and combines complementary information obtained from different cross-linkers and search algorithms. CLMSVault provides filtering, comparison, and visualization tools to support CL-MS analyses and includes a workflow for label-free quantification of cross-linked peptides. An embedded 3D viewer enables the visualization of quantitative data and the mapping of cross-linked sites onto PDB structural models. We demonstrate the application of CLMSVault for the analysis of a noncovalent Cdc34-ubiquitin protein complex cross-linked under different conditions. CLMSVault is open-source software (available at https://gitlab.com/courcelm/clmsvault.git ), and a live demo is available at http://democlmsvault.tyerslab.com/ .

A facile photoelectrochemical sensor for high sensitive ROS and AA detection based on graphitic carbon nitride nanosheets.

PubMed

Motaghed Mazhabi, Robabeh; Ge, Liqin; Jiang, Hui; Wang, Xuemei

2018-06-01

Photoactive material is one of the main challenges for fabrication of sensitive and selective photoelectrochemical (PEC) sensor. Herein, a facile PEC sensor is constructed using graphitic carbon nitride nanosheets (g-C 3 N 4 NSs) coated on the surface of ITO electrode, where electron donor properties of potassium ferrocyanide and ascorbic acid is utilized for the tracing of hydrogen peroxide (H 2 O 2 ), hypochlorite (ClO - ), and ascorbic acid (AA). Our designed PEC sensor exhibits a good linear range to H 2 O 2 concentrations from 12.5 to 875 µM in pH = 7.4 and 2.5-400 µM in pH = 10, while that for AA is in the range from 0.25 to 100 µM in pH = 7.4, and with the same pH for ClO - concentrations in the range from 0.5 to 19 × 10 -3 % (V/V) in a bleach sample. Owing to the good responses towards the traces of H 2 O 2 , AA, and ClO - , our designed system may be used as H 2 O 2, ClO - , and AA sensor for outdoor applications with high specificity, long-time stability and good reproducibility. Copyright © 2018 Elsevier B.V. All rights reserved.

Quick and simple estimation of bacteria using a fluorescent paracetamol dimer-Au nanoparticle composite

NASA Astrophysics Data System (ADS)

Sahoo, Amaresh Kumar; Sharma, Shilpa; Chattopadhyay, Arun; Ghosh, Siddhartha Sankar

2012-02-01

Rapid, simple and sensitive detection of bacterial contamination is critical for safeguarding public health and the environment. Herein, we report an easy method of detection as well as enumeration of the bacterial cell number on the basis of fluorescence quenching of a non-antibacterial fluorescent nanocomposite, consisting of paracetamol dimer (PD) and Au nanoparticles (NPs), in the presence of bacteria. The composite was synthesized by reaction of paracetamol (p-hydroxyacetanilide) with HAuCl4. The Au NPs of the composite were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and selected area electron diffraction analysis. The paracetamol dimer in the composite showed emission peak at 435 nm when excited at 320 nm. The method successfully detected six bacterial strains with a sensitivity of 100 CFU mL-1. The Gram-positive and Gram-negative bacteria quenched the fluorescence of the composite differently, making it possible to distinguish between the two. The TEM analysis showed interaction of the composite with bacteria without any apparent damage to the bacteria. The chi-square test established the accuracy of the method. Quick, non-specific and highly sensitive detection of bacteria over a broad range of logarithmic dilutions within a short span of time demonstrates the potential of this method as an alternative to conventional methods.Rapid, simple and sensitive detection of bacterial contamination is critical for safeguarding public health and the environment. Herein, we report an easy method of detection as well as enumeration of the bacterial cell number on the basis of fluorescence quenching of a non-antibacterial fluorescent nanocomposite, consisting of paracetamol dimer (PD) and Au nanoparticles (NPs), in the presence of bacteria. The composite was synthesized by reaction of paracetamol (p-hydroxyacetanilide) with HAuCl4. The Au NPs of the composite were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and selected area electron diffraction analysis. The paracetamol dimer in the composite showed emission peak at 435 nm when excited at 320 nm. The method successfully detected six bacterial strains with a sensitivity of 100 CFU mL-1. The Gram-positive and Gram-negative bacteria quenched the fluorescence of the composite differently, making it possible to distinguish between the two. The TEM analysis showed interaction of the composite with bacteria without any apparent damage to the bacteria. The chi-square test established the accuracy of the method. Quick, non-specific and highly sensitive detection of bacteria over a broad range of logarithmic dilutions within a short span of time demonstrates the potential of this method as an alternative to conventional methods. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11837h

Two antagonistic gustatory receptor neurons responding to sweet-salty and bitter taste in Drosophila.

PubMed

Hiroi, Makoto; Meunier, Nicolas; Marion-Poll, Frédéric; Tanimura, Teiichi

2004-12-01

In Drosophila, gustatory receptor neurons (GRNs) occur within hair-like structures called sensilla. Most taste sensilla house four GRNs, which have been named according to their preferred sensitivity to basic stimuli: water (W cell), sugars (S cell), salt at low concentration (L1 cell), and salt at high concentration (L2 cell). Labellar taste sensilla are classified into three types, l-, s-, and i-type, according to their length and location. Of these, l- and s-type labellar sensilla possess these four cells, but most i-type sensilla house only two GRNs. In i-type sensilla, we demonstrate here that the first GRN responds to sugar and to low concentrations of salt (10-50 mM NaCl). The second GRN detects a range of bitter compounds, among which strychnine is the most potent; and also to salt at high concentrations (over 400 mM NaCl). Neither type of GRN responds to water. The detection of feeding stimulants in i-type sensilla appears to be performed by one GRN with the combined properties of S+L1 cells, while the other GRN detects feeding inhibitors in a similar manner to bitter-sensitive L2 cells on the legs. These sensilla thus house two GRNs having an antagonistic effect on behavior, suggesting that the expression of taste receptors is segregated across them accordingly. copyright (c) 2004 Wiley Periodicals, Inc.

Amperometric immunosensor for α-fetoprotein antigen in human serum based on co-immobilizing dinuclear copper complex and gold nanoparticle doped chitosan film

NASA Astrophysics Data System (ADS)

Gan, Ning; Meng, Ling Hua; Wang, Feng

2009-09-01

A sensitive amperometric immunosensor for α-fetoprotein (AFP), a tumor marker for the diagnosis of hepatocellular carcinoma (HCC), was constructed, The immunosensor is prepared by co-immobilizing [Cu2(phen)2Cl2] (μ-Cl)2 (CuL), nano-Au/Chitosan(Chit) composite, horseradish peroxidase (HRP) and AFP antibody(anti-AFP) on a glassy carbon electrode (GCE). Firstly, CuL was irreversibly absorb on GCE electrode through π-π stacking interaction; then nano-Au/Chit composite was immobilized onto the electrode because of its excellent membrane-forming ability, finally HRP and anti-AFP was adsorbed onto the surface of the gold nanoparticles to construct GCE | CuL/nanoAu-chit/HRP/anti-AFP immunosensor. The preparation procedure of the electrode was characterized by electrochemical and spectroscopy method. The results showed that this immunosensor exhibited an excellent electrocatalytic response to the reduction of hydrogen peroxide (H2O2) without the aid of an electron mediator, offers a high-sensitivity (1710 nA · ng-1 · ml-1) for the detection of AFP and has good correlation for detection of AFP in the range of 0.2 to 120.0 ng/ml with a detection limit of 0.05 ng/ml. The biosensor showed high selectivity as well as good stability and reproductivity.

The interaction of intracellular Mg2+ and pH on Cl- fluxes associated with intracellular pH regulation in barnacle muscle fibers

PubMed Central

1988-01-01

The intracellular dialysis technique was used to measure unidirectional Cl- fluxes and net acid extrusion by single muscle fibers from the giant barnacle. Decreasing pHi below normal levels of 7.35 stimulated both Cl- efflux and influx. These increases of Cl- fluxes were blocked by disulfonic acid stilbene derivatives such as SITS and DIDS. The SITS- sensitive Cl- efflux was sharply dependent upon pHi, increasing approximately 20-fold as pHi was decreased from 7.35 to 6.7. Under conditions of normal intracellular Mg2+ concentration, the apparent pKa for the activation of Cl- efflux was 7.0. We found that raising [Mg2+]i, but not [Mg2+]o, had a pronounced inhibitory effect on both SITS-sensitive unidirectional Cl- fluxes as well as on SITS-sensitive net acid extrusion. Increasing [Mg2+]i shifted the apparent pKa of Cl- efflux to a more acid value without affecting the maximal flux that could be attained. This relation between pHi and [Mg2+]i on SITS- sensitive Cl- efflux is consistent with a competition between H ions and Mg ions. We conclude that the SITS-inhibitable Cl- fluxes are mediated by the pHi-regulatory transport mechanism and that changes of intracellular Mg2+ levels can modify the activity of the pHi regulator/anion transporter. PMID:3392519

Renal neural mechanisms in salt-sensitive hypertension.

PubMed

DiBona, G F

1995-01-01

Genetic forms of salt (NaCl)-sensitive hypertension are characterized by increased renal sympathetic nerve activity responses to environmental stimuli. The increases in renal sympathetic nerve activity produce marked changes in renal function with renal vasoconstriction and sodium and water retention which can contribute to the initiation, development and maintenance of hypertension. In genetic forms of NaCl-sensitive hypertension, increased dietary NaCl intake produces alterations in norepinephrine kinetics with decreased concentrations of norepinephrine in regions of the anterior hypothalamus which are critical for the regulation of peripheral sympathetic nerve activity. This local central decrease in tonic alpha 2 adrenoceptor sympathoinhibitory input leads to increased peripheral (renal) sympathetic nerve activity and hypertension. Similarly, with increased dietary NaCl intake, patients with NaCl-sensitive hypertension develop increased arterial pressure, renal vasoconstriction, increased glomerular capillary pressure and increased urinary albumin excretion. Thus, increased dietary NaCl intake can, via central nervous system actions, produce increases in renal sympathetic nerve activity whose renal functional effects contribute to the pathophysiology of hypertension.

Angiotensin II modulates salty and sweet taste sensitivities.

PubMed

Shigemura, Noriatsu; Iwata, Shusuke; Yasumatsu, Keiko; Ohkuri, Tadahiro; Horio, Nao; Sanematsu, Keisuke; Yoshida, Ryusuke; Margolskee, Robert F; Ninomiya, Yuzo

2013-04-10

Understanding the mechanisms underlying gustatory detection of dietary sodium is important for the prevention and treatment of hypertension. Here, we show that Angiotensin II (AngII), a major mediator of body fluid and sodium homeostasis, modulates salty and sweet taste sensitivities, and that this modulation critically influences ingestive behaviors in mice. Gustatory nerve recording demonstrated that AngII suppressed amiloride-sensitive taste responses to NaCl. Surprisingly, AngII also enhanced nerve responses to sweeteners, but had no effect on responses to KCl, sour, bitter, or umami tastants. These effects of AngII on nerve responses were blocked by the angiotensin II type 1 receptor (AT1) antagonist CV11974. In behavioral tests, CV11974 treatment reduced the stimulated high licking rate to NaCl and sweeteners in water-restricted mice with elevated plasma AngII levels. In taste cells AT1 proteins were coexpressed with αENaC (epithelial sodium channel α-subunit, an amiloride-sensitive salt taste receptor) or T1r3 (a sweet taste receptor component). These results suggest that the taste organ is a peripheral target of AngII. The specific reduction of amiloride-sensitive salt taste sensitivity by AngII may contribute to increased sodium intake. Furthermore, AngII may contribute to increased energy intake by enhancing sweet responses. The linkage between salty and sweet preferences via AngII signaling may optimize sodium and calorie intakes.

The Connection between Model Performance on the CCMVal Transport Diagnostics and Simulated Sensitivity of Ozone to Chlorine Change

NASA Technical Reports Server (NTRS)

Douglass, Anne; Stolarski, Richard; Oman, Luke; Strahan, Susan

2012-01-01

The chemistry climate models that contributed simulations for past and future ozone evolution to the 2010 Scientific Assessment of Ozone Depletion were subject to extensive evaluation by the SPARC (Stratospheric Processes and their Role in Climate) CCMVal (Chemistry-Climate Model Validation) activity. The sensitivity of ozone to changes in composition and climate varies among the models, but the relationship between these variations and the model evaluations of CCMVal is not obvious. We have learned that the transport evaluation can be used to interpret the comparisons between observed and simulated columns of chlorine reservoirs, hydrochloric acid (HCl) and chlorine nitrate (ClONO2); these comparisons were part of the CCMVal evaluation of chemistry. The simulations with best performance on the transport diagnostics most faithfully reproduce the evolution and seasonal variation of the chlorine reservoirs as observed at NDACC (Network for Detection of Atmospheric Composition Change) stations (NyAlesund 78.9N, Kiruna 67.8N, Harestua 60.2N, Jungfraujoch 46.6N, Toronto 43.6N, Kitt Peak 31.9N, Izana 28.3N, Mauna Loa 19.5N, Lauder 45S and Arrival Heights 77.8S). In the simulations, the HCl in the lower stratosphere depends on total inorganic chlorine (Cly) and partitioning between HCl and ClON02. Total inorganic chlorine depends on the fractional release of chlorine from source gases, and ratio of ClON02 to HCl is inversely dependent on methane and varies quadratically with ozone. Simulated HCl from various models may agree with observations even though Cly is in error, partitioning is in error, or both. Simulated ozone sensitivity to chlorine is shown to be greater for models that produce larger values of chlorine nitrate for background chlorine levels, and vice versa. Comparisons with the NDACC data show why the models with 'best' transport have similar sensitivity to chlorine change. The realistic evolution of the simulated HCl and ClONO2 columns suggests realistic levels of Cly in the lower atmosphere. In addition, the wide range values for the sensitivity of ozone to chlorine obtained from the CCMVal simulations is explained by the wide range in lower atmospheric columns of ClONO2 and the concomitant wide range of levels for chlorine monoxide.

A competitive chemiluminescence enzyme immunoassay for rapid and sensitive determination of enrofloxacin

NASA Astrophysics Data System (ADS)

Yu, Fei; Wu, Yongjun; Yu, Songcheng; Zhang, Huili; Zhang, Hongquan; Qu, Lingbo; Harrington, Peter de B.

With alkaline phosphatase (ALP)-adamantane (AMPPD) system as the chemiluminescence (CL) detection system, a highly sensitive, specific and simple competitive chemiluminescence enzyme immunoassay (CLEIA) was developed for the measurement of enrofloxacin (ENR). The physicochemical parameters, such as the chemiluminescent assay mediums, the dilution buffer of ENR-McAb, the volume of dilution buffer, the monoclonal antibody concentration, the incubation time, and other relevant variables of the immunoassay have been optimized. Under the optimal conditions, the detection linear range of 350-1000 pg/mL and the detection limit of 0.24 ng/mL were provided by the proposed method. The relative standard deviations were less than 15% for both intra and inter-assay precision. This method has been successfully applied to determine ENR in spiked samples with the recovery of 103%-96%. It showed that CLEIA was a good potential method in the analysis of residues of veterinary drugs after treatment of related diseases.

A chemiluminescence biosensor based on the adsorption recognition function between Fe3O4@SiO2@GO polymers and DNA for ultrasensitive detection of DNA

NASA Astrophysics Data System (ADS)

Sun, Yuanling; Li, Jianbo; Wang, Yanhui; Ding, Chaofan; Lin, Yanna; Sun, Weiyan; Luo, Chuannan

2017-05-01

In this work, a chemiluminescence (CL) biosensor was prepared for ultrasensitive determination of deoxyribonucleic acid (DNA) based on the adsorption recognition function between core-shell Fe3O4@SiO2 - graphene oxide (Fe3O4@SiO2@GO) polymers and DNA. The Fe3O4@SiO2@GO polymers were composed by GO and magnetite nanoparticles. And the core-shell polymers were confirmed by Scanning Electron Microscope (SEM), X-Ray Powder Diffraction (XRD) and Fourier Transform Infrared (FTIR). Then Fe3O4@SiO2@GO was modified by DNA. Based on the principle of complementary base, Fe3O4@SiO2@GO-DNA was introduced to the CL system and the selectivity, sensitivity of DNA detection was significantly improved. The adsorption properties of Fe3O4@SiO2@GO to DNA were researched through the adsorption equilibrium, adsorption kinetic and thermodynamics. Under optimized CL conditions, DNA could be assayed with the linear concentration range of 5.0 × 10- 12-2.5 × 10- 11 mol/L. The detection limit was 1.7 × 10- 12 mol/L (3δ) and the relative standard deviation (RSD) was 3.1%. The biosensor was finally used for the determination of DNA in laboratory samples and recoveries ranged from 99% to 103%. The satisfactory results revealed the potential application of Fe3O4@SiO2@GO-DNA-CL biosensor in the diagnosis and the treatment of human genetic diseases.

Post-chemiluminescence determination of chloramphenicol based on luminol-potassium periodate system.

PubMed

Yang, Xiao Feng; Li, Nian Bing; Luo, Hong Qun

2012-01-01

A post-chemiluminescence (PCL) phenomenon was observed when chloramphenicol was injected into a mixture of luminol and potassium periodate after the chemiluminescence (CL) reaction of luminol-potassium periodate had finished. The possible reaction mechanism was proposed based on studies of the CL kinetic characteristics, the CL spectra, the fluorescence spectra and the UV-vis absorption spectra of the related substances. Based on the PCL reaction, a rapid and sensitive method for the determination of chloramphenicol was established. The linear response range was 6.0 × 10(-7) -1.0 × 10(-5) mol/L, with a correlation coefficient of 0.9986. The relative standard deviation (RSD) for 5.0 × 10(-6) mol/L chloramphenicol was 2.3% (n = 11). The detection limit was 1.6 × 10(-7) mol/L. The method has been applied to the determination of chloramphenicol in pharmaceutical samples with satisfactory results. Copyright © 2011 John Wiley & Sons, Ltd.

Determination of Sulfonamide Residues in Food by Capillary Zone Electrophoresis with On-Line Chemiluminescence Detection Based on an Ag(III) Complex

PubMed Central

Dai, Tingting; Duan, Jie; Li, Xinghua; Xu, Xiangdong; Shi, Hongmei; Kang, Weijun

2017-01-01

The presence of sulfonamide (SA) residues in foods is largely due to the raising of animals with sulfonamide antibiotics added or polluted feedstuff. In this paper, a sensitive method was developed for the determination of the residues of three sulfonamides in animal-derived food; the SAs include sulfadimidine (SDD), sulfadiazine (SDZ), and sulfathiazole (STZ). The method is based on capillary zone electrophoresis (CE) with online chemiluminescence (CL) detection, using an Ag(III) complex as an oxidant. These SAs have an inhibiting effect on the Ag(III)–luminol CL reaction. The electrophoretic buffer is 12.0 mM sodium borate. Under a set of optimized conditions, the linear ranges for the detections were found to be 10.0–200 µg·mL−1 for SDD and SDZ, and 2.0–50.0 µg·mL−1 for STZ. The detection limits were 2.75, 3.14, and 0.65 µg·mL−1 for SDD, SDZ, and STZ, respectively. Relative standard deviations (RSD) for the peak heights were between 2.1% and 2.8% (n = 7). The proposed method was used in the analysis of the SAs in samples from pork meat, chicken meat, and milk, showing satisfactory detection results. A reaction mechanism was also proposed for the Ag(III)–luminol–SA CL reactions. The method has potential applications for the monitoring of residue levels of the three SAs in food, providing food safety data. PMID:28621728

A single use electrochemical sensor based on biomimetic nanoceria for the detection of wine antioxidants.

PubMed

Andrei, Veronica; Sharpe, Erica; Vasilescu, Alina; Andreescu, Silvana

2016-08-15

We report the development and characterization of a disposable single use electrochemical sensor based on the oxidase-like activity of nanoceria particles for the detection of phenolic antioxidants. The use of nanoceria in the sensor design enables oxidation of phenolic compounds, particularly those with ortho-dihydroxybenzene functionality, to their corresponding quinones at the surface of a screen printed carbon electrode. Detection is carried out by electrochemical reduction of the resulting quinone at a low applied potential of -0.1V vs the Ag/AgCl electrode. The sensor was optimized and characterized with respect to particle loading, applied potential, response time, detection limit, linear concentration range and sensitivity. The method enabled rapid detection of common phenolic antioxidants including caffeic acid, gallic acid and quercetin in the µM concentration range, and demonstrated good functionality for the analysis of antioxidant content in several wine samples. The intrinsic oxidase-like activity of nanoceria shows promise as a robust tool for sensitive and cost effective analysis of antioxidants using electrochemical detection. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of silver nanoparticles to the chemiluminescence determination of cefditoren pivoxil using the luminol-ferricyanide system.

PubMed

Alarfaj, Nawal A; Aly, Fatma A; El-Tohamy, Maha F

2015-02-01

A new simple, accurate and sensitive sequential injection analysis chemiluminescence (CL) detection method for the determination of cefditoren pivoxil (CTP) has been developed. The developed method was based on the enhancement effect of silver nanoparticles on the CL signal arising from a luminol-potassium ferricyanide reaction in the presence of CTP. The optimum conditions relevant to the effect of luminol, potassium ferricyanide and silver nanoparticle concentrations were investigated. The proposed method showed linear relationships between relative CL intensity and the investigated drug concentration at the range 0.001-5000 ng/mL, (r = 0.9998, n = 12) with a detection limit of 0.5 pg/mL and quantification limit of 0.001 ng/mL. The relative standard deviation was 1.6%. The proposed method was employed for the determination of CTP in bulk drug, in its pharmaceutical dosage forms and biological fluids such as human serum and urine. The interference of some common additive compounds such as glucose, lactose, starch, talc and magnesium stearate was investigated. In addition, the interference of some related cephalosporins was tested. No interference was recorded. The obtained sequential injection analysis-CL results were statistically compared with those from a reported method and did not show any significant differences. Copyright © 2014 John Wiley & Sons, Ltd.

Detection of species and molecular typing of Leishmania in suspected patients by targeting cytochrome b gene in Zahedan, southeast of Iran.

PubMed

Mirahmadi, Hadi; Rezaee, Nasrin; Mehravaran, Ahmad; Heydarian, Peyman; Raeghi, Saber

2018-05-01

Cutaneous leishmaniasis (CL) is one of the most important health problems that are capable of involving both tropical and subtropical areas, especially in Iran. This cross-sectional study aimed to differentiate the species that are able to cause CL in Zahedan city by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. It was conducted on 145 suspected CL patients in Zahedan city between 2014 and 2016. The smears were initially prepared, air-dried, fixed with absolute methanol, and stained with 10% Giemsa. Then, we examined the stained samples by a light microscope under 1000× magnifications. PCR assay targeted cytochrome b (cyt b ) gene using LCBF1 and LCBR2 primers and the products digested by Ssp1 enzymes. From 145 suspected CL patients, 76 (52.4%) were positive in microscopic examination. In addition, we detected gene of interest (cyt b ) in 98 (67.5%). The results of PCR-RFLP indicated that 53/98 (54%) cases were Leishmania major and 45/98 (46%) were Leishmania tropica , and the main species in these areas was L. major . We concluded that the microscopic examination is not sensitive enough and is not able to distinguish between different Leishmania species. Instead, molecular methods like PCR-RFLP can be appropriately used with promising results.

Flow injection chemiluminescence determination of the total phenolics levels in plant-derived beverages using soluble manganese(IV).

PubMed

Nalewajko-Sieliwoniuk, Edyta; Tarasewicz, Iwona; Kojło, Anatol

2010-05-23

This study established a flow injection (FI) methodology for the determination of the total phenolic content in plant-derived beverages based on soluble manganese(IV) chemiluminescence (CL) detection. It was found that mixing polyphenols with acidic soluble manganese(IV) in the presence of formaldehyde evoked chemiluminescence. Based on this finding, a new FI-CL method was developed for the estimation of the total content of phenolic compounds (expressed as milligrams of gallic acid equivalent per litre of drink) in a variety of wine, tea and fruit juice samples. The proposed method is sensitive with a detection limit of 0.02 ng mL(-1) (gallic acid), offers a wide linear dynamic range (0.5-400 ng mL(-1)) and high sample throughput (247 samples h(-1)). The relative standard deviation for 15 measurements was 3.8% for 2 ng mL(-1) and 0.45% for 10 ng mL(-1) of gallic acid. Analysis of 36 different samples showed that the results obtained by the proposed FI-CL method correlate highly with those obtained by spectrophotometric methods commonly used for the evaluation of the total phenolic/antioxidant level. However, the FI-CL method was found to be far simpler, more rapid and selective, with almost no interference from non-phenolic components of the samples examined. Copyright 2010 Elsevier B.V. All rights reserved.

Thin film organic photodetectors for indirect X-ray detection demonstrating low dose rate sensitivity at low voltage operation

NASA Astrophysics Data System (ADS)

Starkenburg, Daken J.; Johns, Paul M.; Baciak, James E.; Nino, Juan C.; Xue, Jiangeng

2017-12-01

Developments in the field of organic semiconductors have generated organic photodetectors with high quantum efficiency, wide spectral sensitivity, low power consumption, and unique form factors that are flexible and conformable to their substrate shape. In this work, organic photodetectors coupled with inorganic CsI(Tl) scintillators are used to showcase the low dose rate sensitivity that is enabled when high performance organic photodetectors and scintillator crystals are integrated. The detection capability of these organic-inorganic coupled systems to high energy radiation highlights their potential as an alternative to traditional photomultiplier tubes for nuclear spectroscopy applications. When exposed to Bremsstrahlung radiation produced from an X-ray generator, SubPc:C60, AlPcCl:C70, and P3HT:PC61BM thin film photodetectors with active layer thicknesses less than 100 nm show detection of incident radiation at low and no applied bias. Remarkably low dose rates, down to at least 0.18 μGy/s, were detectable with a characteristic linear relationship between exposure rate and photodetector current output. These devices also demonstrate sensitivities as high as 5.37 mC Gy-1 cm-2 when coupled to CsI(Tl). Additionally, as the tube voltage across the X-ray generator was varied, these organic-inorganic systems showed their ability to detect a range of continuous radiation spectra spanning several hundred keV.

A novel on-line gold nanoparticle-catalyzed luminol chemiluminescence detector for high-performance liquid chromatography.

PubMed

Zhang, Qun Lin; Wu, Liang; Lv, Chen; Zhang, Xiao Yue

2012-06-15

A novel on-line gold nanoparticle-catalyzed luminol-H(2)O(2) chemiluminescence (CL) detector for high-performance liquid chromatography (HPLC) was established, in which gold nanoparticles were produced by the on-line reaction of H(2)O(2), NaHCO(3)-Na(2)CO(3) (buffer solution of luminol), and HAuCl(4). Eight phenolic compounds (gallic acid, protocatechuic acid, protocatechuic aldehyde, 2,5-dihydroxybenzoic acid, caffeic acid, 2,3-dihydroxybenzoic acid, (+)-catechin, and (-)-epicatechin) were chosen as the model compounds. Every separated phenolic compound in the column eluent strongly enhanced the CL signal of on-line gold nanoparticle-catalyzed luminol system. The CL and UV-visible absorption spectra and transmission electron microscopy studies were carried out, and the CL enhancement mechanism was ascribed to that the presence of phenolic compound promoted the on-line formation of 38-nm-diameter gold nanoparticles, which better catalyzed the luminol-H(2)O(2) CL reaction. The effects of methanol and phosphoric acid in the proposed HPLC configuration were performed by two gradient elution programs, and the baseline profile revealed that on-line gold nanoparticle-catalyzed luminol-H(2)O(2) CL detector had better compatibility than 38 nm gold colloids-luminol-H(2)O(2) CL detector. The proposed CL detector exhibits excellent analytical performance with the low detection limit (S/N=3) of 0.53-0.97 ng/mL (10.6-19.4 pg) phenolic compounds, and offers a new strategy for developing on-line nanoparticle-catalyzed CL detector for HPLC with sensitive analysis. Copyright © 2012 Elsevier B.V. All rights reserved.

Sensitized chemiluminescence of 2-phenyl-4,5-di(2-furyl)-1H-imidazole/K₃Fe(CN)₆/propyl gallate system combining with solid-phase extraction for the determination of propyl gallate in edible oil.

PubMed

Kang, Jing; Han, Lu; Chen, Zhonglin; Shen, Jimin; Nan, Jun; Zhang, Yihua

2014-09-15

In this paper, a novel chemiluminescence (CL) method has been developed for the determination of propyl gallate (PG). The proposed method was based on the enhancing effect of PG on the CL signal of 2-phenyl-4,5-di(2-furyl)-1H-imidazole (PDFI) and K3Fe(CN)6 reaction in an alkaline solution. Under the optimum conditions, the enhanced CL intensity was linearly related to the concentration of PG. The linear range of the calibration curve was 0.05-8 μg/mL, and the corresponding detection limit (3σ) was 0.036 μg/mL. The relative standard deviation for determining 1.0 μg/mL PG was 2.8% (n=11). The proposed method has been successfully applied to the determination of PG in edible oil. The edible oil samples were prepared by the solid-phase extraction (SPE) with a C18 column served as the stationary phase. Furthermore, the possible CL mechanism was also discussed briefly based on the photoluminescence (PL) and CL spectra. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determination of 2-methoxyestradiol in serum samples and pharmaceutical preparations by silver nanoparticles-enhanced chemiluminescence.

PubMed

Zhang, Min; Xiao, Xiangqin; Zeng, Wenyuan; Zeng, Xiaoying; Yao, Hanchun

2014-03-01

Silver nanoparticles (AgNPs) exhibited better chemiluminescence (CL) catalysis activity and smaller nanoparticles have stronger catalysis ability in luminol-K3Fe(CN)6 system among the synthesized AgNPs of different size. 10±2 nm nanoparticles was used as catalysts to enhance the reaction sensitivity. It was found that the CL intensity of AgNPs-luminol-K3Fe(CN)6 was strongly inhibited in the presence of 2-methoxyestradiol (2-ME) and the relative CL intensity was in linear correlation with the concentration of 2-ME. Thus, the silver nanoparticles-enhanced CL method for the determination of 2-ME was developed. The proposed method has a detection limit (3 Sb/K) of 5.0×10(-10) mol L(-1) with a relative standard deviation of 0.75% for 5.0×10(-8) mol L(-1) 2-ME. The method was successfully applied for determination of 2-ME in human serum and pharmaceutical preparations. The possible CL reaction mechanism was also discussed briefly. Oxygen radicals played an important role in the catalytic process. Copyright © 2013 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer based on chemiluminescence imaging for the chiral recognition of dansyl-phenylalanine.

PubMed

Wang, Li; Zhang, Zhujun; Huang, Lianggao

2008-03-01

A new molecularly imprinted polymer (MIP)-chemiluminescence (CL) imaging detection approach towards chiral recognition of dansyl-phenylalanine (Phe) is presented. The polymer microspheres were synthesized using precipitation polymerization with dansyl-L-Phe as template. Polymer microspheres were immobilized in microtiter plates (96 wells) using poly(vinyl alcohol) (PVA) as glue. The analyte was selectively adsorbed on the MIP microspheres. After washing, the bound fraction was quantified based on peroxyoxalate chemiluminescence (PO-CL) analysis. In the presence of dansyl-Phe, bis(2,4,6-trichlorophenyl)oxalate (TCPO) reacted with hydrogen peroxide (H2O2) to emit chemiluminescence. The signal was detected and quantified with a highly sensitive cooled charge-coupled device (CCD). Influencing factors were investigated and optimized in detail. Control experiments using capillary electrophoresis showed that there was no significant difference between the proposed method and the control method at a confidence level of 95%. The method can perform 96 independent measurements simultaneously in 30 min and the limits of detection (LODs) for dansyl-L-Phe and dansyl-D-Phe were 0.025 micromol L(-1) and 0.075 micromol L(-1) (3sigma), respectively. The relative standard deviation (RSD) for 11 parallel measurements of dansyl-L-Phe (0.78 micromol L(-1)) was 8%. The results show that MIP-based CL imaging can become a useful analytical technology for quick chiral recognition.

Serological diagnosis of mumps: Value of the titration of specific IgG.

PubMed

Sanz, Juan Carlos; Ramos, Belén; Fernández, Aurora; García-Comas, Luis; Echevarría, Juan Emilio; de Ory, Fernando

2018-03-01

The aim of this study was to evaluate a cut-off point of the titration of IgG by ELISA in the diagnosis of mumps. A study was made of serum samples from 85 mumps cases (confirmed by PCR in saliva) and 2,351 controls of the general population of the Region of Madrid. The IgM detection was positive in 21 cases (sensitivity of 24.7%). The best cut-off point corresponded to IgG titres ≥4,900 (sensitivity of 64.7% and specificity of 86.1%). Among 42 patients immunised with at least one dose of measles mumps, rubella vaccine IgM was detected in 4 cases. However, the detection of IgG ≥4,900 was positive in 29 (sensitivity of 69.0%). An IgG result of ≥4.900 was almost 5 times more probable in a patient with mumps than in a non-infected patient. The detection of high titres of IgG against mumps could improve the IgM results in vaccinated people. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Amiloride-Sensitive and Amiloride-Insensitive Responses to NaCl + Acid Mixtures in Hamster Chorda Tympani Nerve

PubMed Central

Hettinger, Thomas P.; Savoy, Lawrence D.; Frank, Marion E.

2012-01-01

Component signaling in taste mixtures containing both beneficial and dangerous chemicals depends on peripheral processing. Unidirectional mixture suppression of chorda tympani (CT) nerve responses to sucrose by quinine and acid is documented for golden hamsters (Mesocricetus auratus). To investigate mixtures of NaCl and acids, we recorded multifiber responses to 50 mM NaCl, 1 and 3 mM citric acid and acetic acid, 250 μM citric acid, 20 mM acetic acid, and all binary combinations of each acid with NaCl (with and without 30 μM amiloride added). By blocking epithelial Na+ channels, amiloride treatment separated amiloride-sensitive NaCl-specific responses from amiloride-insensitive electrolyte-generalist responses, which encompass all of the CT response to the acids as well as responses to NaCl. Like CT sucrose responses, the amiloride-sensitive NaCl responses were suppressed by as much as 50% by citric acid (P = 0.001). The amiloride-insensitive electrolyte-generalist responses to NaCl + acid mixtures approximated the sum of NaCl and acid component responses. Thus, although NaCl-specific responses to NaCl were weakened in NaCl–acid mixtures, electrolyte-generalist responses to acid and NaCl, which tastes KCl-like, were transmitted undiminished in intensity to the central nervous system. The 2 distinct CT pathways are consistent with known rodent behavioral discriminations. PMID:22451526

A sensitive gold nanoparticles sensing platform based on resonance energy transfer for chemiluminescence light on detection of biomolecules.

PubMed

Qin, Guoxing; Zhao, Shulin; Huang, Yong; Jiang, Jing; Liu, Yi-Ming

2013-08-15

In this article, we report a gold nanoparticles (AuNPs) sensing platform based on chemiluminescence resonance energy transfer (CRET) for light on detection of biomolecules. In designing such a CRET-based biosensing platform, the aptamer was first covalently labeled with a chemiluminescent reagent, N-(4-aminobutyl)-N-ethylisoluminol (ABEI). The ABEI labeled aptamer was then hybridized with AuNPs functionalized ssDNA which was complementary to the aptamer, obtaining the aptasensor. The CRET between ABEI and AuNPs in the aptasensor led to the CL quenching of ABEI. In the presence of a target analyte, it formed a complex with aptamer, and released ABEI-aptamer from AuNPs surface that resulted in CL recovery of ABEI. To test this design, a thrombin (used as a model analyte) aptasensor was prepared and evaluated. The results indicate that the proposed approach is simple and provided a linear range of 50-550 pM for thrombin detection with a detection limit of 15 pM. This new methodology can be easily extended to assay other biomolecules by simply changing the recognition sequence with the substrate aptamer. Copyright © 2013 Elsevier B.V. All rights reserved.

Mass spectrometer characterization of halogen gases in air at atmospheric pressure.

PubMed

Ivey, Michelle M; Foster, Krishna L

2005-03-01

We have developed a new interface for a commercial ion trap mass spectrometer equipped with APCI capable of real-time measurements of gaseous compounds with limits of detection on the order of pptv. The new interface has been tested using the detection of Br2 and Cl2 over synthetic seawater ice at atmospheric pressure as a model system. A mechanical pump is used to draw gaseous mixtures through a glass manifold into the corona discharge area, where the molecules are ionized. Analysis of bromine and chlorine in dry air show that ion intensity is affected by the pumping rate and the position of the glass manifold. The mass spectrometer signals for Br2 are linear in the 0.1-10.6 ppbv range, and the estimated 3sigma detection limit is 20 pptv. The MS signals for Cl2 are linear in the 0.2-25 ppbv range, and the estimated 3sigma detection limit is 1 ppbv. This new interface advances the field of analytical chemistry by introducing a practical modification to a commercially available ion trap mass spectrometer that expands the available methods for performing highly specific and sensitive measurements of gases in air at atmospheric pressure.

On-line and in-situ detection of polycyclic aromatic hydrocarbons (PAH) on aerosols via thermodesorption and laser-induced fluorescence spectroscopy.

PubMed

Panne, U; Knöller, A; Kotzick, R; Niessner, R

2000-02-01

A fiber optical sensor system for the determination of polycyclic aromatic hydrocarbons (PAH) on aerosols by laser-induced, time-resolved fluorescence is combined with a thermodesorption device. The sensor system is based on an aerosol flow cell, which is fibre-optically coupled to a pulsed nitrogen laser for excitation and the detection system. Time-resolved fluorescence emission spectra are detected by a monochromator equipped with a photomultiplier and a fast digital storage oscilloscope. The analytical figures of merit of the thermodenuder are reported for benzo[a]pyrene, benzo[b]fluoranthene, and benzo[ghi]-perylene on ultrafine soot and NaCl aerosols. By thermodesorption of the PAH, problems due to quenching of the PAH fluorescence by the bulk aerosol material or excimer formation on the aerosol surface were avoided. For the PAH under study, the sensitivity was improved considerably and detection limits between 110 and 850 ng m(-3) were attained, while a response time of 2-3 min was achieved with the thermodenuder. A calibration for PAH on ultrafine soot and NaCl aerosols was established independent of the aerosol substrate.

Solvo-thermal synthesis of a unique alkaline earth-transition Ba-Cd micro-porous coordination framework as hetero-metallic luminescent sensor for Cu2+ and real-time detection of benzaldehyde

NASA Astrophysics Data System (ADS)

Ding, Bin; Ma, Dian Xue; Zhang, Hui Min; Meng, Xin; Qiu, Rong Rong; Ren, Rong; Wu, Jie; Wu, Xiang Xia; Huo, Jian Zhong; Liu, Yuan Yuan; Shi, Xue Fang

2018-06-01

In this work a unique hetero-metallic alkaline earth-transition Ba-Cd luminescent micro-porous metal-organic framework {[BaCd(μ6-tp)1.5(μ2-Cl)(H2O) (DMF)2]·0.75H2O}n (H2tp = terephthalic acid) (1) has been prepared under solvo-thermal conditions. In 1 infinite 1D {Ba-X-Cd} (X = O, Cl) inorganic chains are linked via these full de-pronated tp2- ligands forming a unique 3D I1O2 type micro-porous coordination framework. PXRD patterns of 1 have been determined confirming pure phases of 1. Luminescence investigations suggested that 1 exhibits highly selective and sensitive sensing for trace amounts of benzaldehyde in ethanol, which provides a facile method for real-time detection of benzaldehyde. Meanwhile 1 also exhibits highly selective and sensitive sensing for Cu2+ over other cations with high quenching efficiency Ksv value 1.15 × 104 L·mol-1. As far as we know, 1 represents the first example of alkaline earth-transition hetero-metallic Ba-Cd micro-porous coordination framework as bi-functional luminescent probes for Cu2+ and benzaldehyde.

Solvo-thermal synthesis of a unique alkaline earth-transition Ba-Cd micro-porous coordination framework as hetero-metallic luminescent sensor for Cu2+ and real-time detection of benzaldehyde.

PubMed

Ding, Bin; Ma, Dian Xue; Zhang, Hui Min; Meng, Xin; Qiu, Rong Rong; Ren, Rong; Wu, Jie; Wu, Xiang Xia; Huo, Jian Zhong; Liu, Yuan Yuan; Shi, Xue Fang

2018-06-15

In this work a unique hetero-metallic alkaline earth-transition Ba-Cd luminescent micro-porous metal-organic framework {[BaCd(μ 6 -tp) 1.5 (μ 2 -Cl)(H 2 O) (DMF) 2 ]·0.75H 2 O} n (H 2 tp=terephthalic acid) (1) has been prepared under solvo-thermal conditions. In 1 infinite 1D {Ba-X-Cd} (X=O, Cl) inorganic chains are linked via these full de-pronated tp 2- ligands forming a unique 3D I 1 O 2 type micro-porous coordination framework. PXRD patterns of 1 have been determined confirming pure phases of 1. Luminescence investigations suggested that 1 exhibits highly selective and sensitive sensing for trace amounts of benzaldehyde in ethanol, which provides a facile method for real-time detection of benzaldehyde. Meanwhile 1 also exhibits highly selective and sensitive sensing for Cu 2+ over other cations with high quenching efficiency K sv value 1.15×10 4 L·mol -1 . As far as we know, 1 represents the first example of alkaline earth-transition hetero-metallic Ba-Cd micro-porous coordination framework as bi-functional luminescent probes for Cu 2+ and benzaldehyde. Copyright © 2018 Elsevier B.V. All rights reserved.

Chemiluminescence microfluidic system of gold nanoparticles enhanced luminol-silver nitrate for the determination of vitamin B12.

PubMed

Kamruzzaman, Mohammad; Alam, Al-Mahmnur; Kim, Kyung Min; Lee, Sang Hak; Kim, Young Ho; Kabir, A N M Hamidul; Kim, Gyu-Man; Dang, Trung Dung

2013-02-01

A rapid and sensitive chemiluminescence (CL) system coupled with a microfluidic chip has been presented to determine vitamin B12 (VB12) based on the reaction of luminol and silver nitrate (AgNO(3)) in the presence of gold nanoparticles (AuNPs). A microfluidic chip was fabricated by a soft-lithographic procedure using polydimethyl siloxane (PDMS) having four inlets and one outlet with a 200 μm wide, 250 μm deep, and 100 mm long microchannel. Ag(+) was used as a chemiluminogenic oxidant in this CL reaction which oxidized luminol to produce strong CL signal in the presence of AuNPs. Luminol reacted with AgNO(3) under the catalysis of AuNPs to produce luminol radicals which reacted with dissolved oxygen and emitted CL light. The proposed CL system was applied to determine the amount of VB12 in VB12 tablets and multivitamin. Under the optimum conditions, the CL intensity of the system was increased with the concentration of VB12 in the range of 0.25-100 ng mL(-1) with the correlation coefficient of 0.9982. The limit of detection was found to be 0.04 ng mL(-1) with the relative standard deviation of 1.56 % for five replicate determinations of 25 ng mL(-1) of VB12. The CL reaction mechanism was demonstrated by UV-visible spectra and CL emission spectra.

PCR detection of psychrophilic Clostridium spp. causing 'blown pack' spoilage of vacuum-packed chilled meats.

PubMed

Broda, D M; Boerema, J A; Bell, R G

2003-01-01

To develop a practical molecular procedure that directly, without isolation, and specifically detects the presence of clostridia which cause 'blown pack' spoilage of vacuum-packed meat. Primer sets and PCR amplification procedures were developed that detect the presence of 16S rDNA gene and/or 16S-23S rDNA internal transcribed spacer fragments of 'blown pack' causing clostridia in meat. The specificity of the developed procedures was evaluated with DNA obtained from close phylogenetic neighbours of 'blown pack' causing clostridia, food clostridia and common meat spoilage microorganisms. The sensitivity of detection was assessed in non-enriched and low-temperature-enriched beef mince inoculated with serially diluted pure cultures of Clostridium estertheticum DSMZ 8809T and Cl. gasigenes DB1AT. The efficacy of detection procedures was evaluated for naturally contaminated vacuum-packed meat samples. Three primer sets, 16SE, 16SDB and EISR, produced amplicons of the expected size with DNA templates from target clostridia, but failed to yield PCR products with DNAs from any other microorganisms tested. With 16SE and 16SDB primers, minimum levels of detection were 104 CFU g(-1) for non-enriched, and 102 CFU g(-1) for enriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, Cl. gasigenes was confirmed as the causative agent of 'blown pack' spoilage in two packs, and Cl. estertheticum as the causative agent in the third. The developed method can be used for rapid detection of 'blown pack' causing clostridia in commercial blown packs, or following low temperature enrichment, for detection of these microorganisms in meat containing as few as 100 clostridial cells per gram. The paper reports practical procedures that can be used for rapid confirmation of the causative agents of clostridial 'blown pack' spoilage in commercial spoiled packs, or for detection of psychrophilic clostridia in epidemiological trace back of 'blown pack' spoilage incidents in meat processing plants.

Flow injection chemiluminescence determination of lercanidipine based on N-chlorosuccinimide-eosin Y post-chemiluminescence reaction.

PubMed

Wang, Guowei; Zhao, Fang; Gao, Ying

2014-12-01

A novel post-chemiluminescence (PCL) reaction was discovered when lercanidipine was injected into the CL reaction mixture of N-chlorosuccinimide with alkaline eosin Y in the presence of cetyltrimethylammonium bromide (CTAB), where eosin Y was used as the CL reagent and CTAB as the surfactant. Based on this observation, a simple and highly sensitive PCL method combined with a flow injection (FI) technique was developed for the assay of lercanidipine. Under optimum conditions, the CL signal was linearly related to the concentration of lercanidipine in the range 7.0 × 10(-10) to 3.0 × 10(-6)  g/mL with a detection limit of 2.3 × 10(-10) g/mL (3σ). The relative standard deviation (RSD) was 2.1% for 1.0 × 10(-8) g/mL lercanidipine (n = 13). The proposed method had been applied to the estimation of lercanidipine in tablets and human serum samples with satisfactory results. The possible CL mechanism is also discussed briefly. Copyright © 2014 John Wiley & Sons, Ltd.

Fluorescent determination of chloride in nanoliter samples.

PubMed

García, N H; Plato, C F; Garvin, J L

1999-01-01

Measurements of Cl- in nanoliter samples, such as those collected during isolated, perfused tubule experiments, have been difficult, somewhat insensitive, and/or require custom-made equipment. We developed a technique using a fluorescent Cl- indicator, 6-methoxy-N-(3-sulfopropyl) quinolinium (SPQ), to make these measurements simple and reliable. This is a simple procedure that relies on the selectivity of the dye and the fact that Cl-quenches its fluorescence. To measure millimolar quantities of Cl- in nanoliter samples, we prepared a solution of 0.25 mm SPQ and loaded it into the reservoir of a continuous-flow ultramicrofluorometer, which can be constructed from commercially available components. Samples were injected with a calibrated pipette via an injection port, and the resultant peak fluorescent deflections were recorded. The deflections represent a decrease in fluorescence caused by the quenching effect of the Cl- injected. The method yielded a linear response with Cl- concentrations from 5 to 200 mm NaCl. The minimum detectable Cl- concentration was approximately 5 mm. The coefficient of variation between 5 and 200 mm was 1.7%. Resolution, defined as two times the standard error divided by the slope, between 10 and 50 mm and between 50 and 200 mm was 1 mm and 2.6 mm, respectively. Furosemide, diisothiocyanostilbene-2,2'-disulfonic acid and other nonchloride anions (HEPES, HCO3, SO4, and PO4) did not interfere with the assay, whereas 150 mm NaBr resulted in a peak height greater than 150 NaCl. In addition, the ability to measure Cl- did not vary with pH within the physiological range. We developed an easy, accurate, and sensitive method to measure Cl- concentration in small aqueous solution samples.

A new specific ageusia: some humans cannot taste L-glutamate.

PubMed

Lugaz, O; Pillias, A-M; Faurion, A

2002-02-01

A new specific ageusia was found in human subjects for monosodium L-glutamate (MSG). Four tests were successively applied to discriminate non-tasters and hypotasters from tasters. (i) NaCl and MSG thresholds, and (ii) suprathreshold sensitivity were evaluated using the up-and-down procedure. Only 73% of 109 subjects common to both tests demonstrated a sensitivity for MSG significantly higher than their sensitivity to NaCl, and hence a specific sensitivity to L-glutamate. The remaining 27% who showed no significant difference in sensitivity to MSG and NaCl solutions were considered as putative hypotasters. (iii) Perception profiles (time-intensity) for MSG and NaCl were tested in 58 subjects and appeared significantly different in 47 tasters (81%). This technique helped in identifying among putative hypotasters of tests 1 and 2 a few tasters who perceived equal intensity for isoconcentration of NaCl and MSG but who could discriminate isomolar solutions on other cues. Thus, 19% of subjects, for whom no significant differences were found between MSG and NaCl time-intensity profiles, remained in the hypotaster group. (iv) A discrimination task including 24 triangular presentations per subject of NaCl and MSG 29 mM applied to the eight most severe hypotasters showed that two subjects at least (two of 58; 3.5%) could not discriminate between both stimuli. Moreover, these subjects probably perceived identical sensations for MSG and NaCl solutions. The six other hypotasters (10.3%) could discriminate both stimuli at the limit of significance. None of these eight subjects were able to identify the typical umami taste in 29 mM MSG.

Aspects of Salt Tolerance in a NaCl-Selected Stable Cell Line of Citrus sinensis1

PubMed Central

Ben-Hayyim, Gozal; Kochba, Joshua

1983-01-01

A NaCl-tolerant cell line which was selected from ovular callus of `Shamouti' orange (Citrus sinensis L. Osbeck) proved to be a true cell line variant. This conclusion is based on the following observations. (a) Cells which have been removed from the selection pressure for at least four passages retain the same NaCl tolerance as do cells which are kept constantly on 0.2 molar NaCl. (b) Na+ and Cl− uptake are considerably lower in salt-tolerant cells (R-10) than in salt-sensitive cells (L-5) at a given external NaCl concentration. (c) Growth of salt-tolerant cells is markedly suppressed upon replacement of NaCl by KCl, whereas the growth of salt-sensitive cells is only slightly affected. Accumulation of K+ and Cl− accompanies the inhibition of growth. Experiments carried out with sodium and potassium sulfate suggest that the toxic effect is due to the accumulated Cl−. (d) Removal of Ca2+ from the growth medium severely inhibits the growth of salt-tolerant cells in the presence of NaCl, while it has a minor effect on growth of salt-sensitive cells in the presence of NaCl. (e) Electron micrographs show that the salt-tolerant cells have very big vacuoles when exposed to salt, while the size of the vacuoles of the salt-sensitive cells does not change. Images Fig. 3 PMID:16663067

Porous palladium coated conducting polymer nanoparticles for ultrasensitive hydrogen sensors

NASA Astrophysics Data System (ADS)

Lee, Jun Seop; Kim, Sung Gun; Cho, Sunghun; Jang, Jyongsik

2015-12-01

Hydrogen, a clean-burning fuel, is of key importance to various industrial applications, including fuel cells and in the aerospace and automotive industries. However, hydrogen gas is odorless, colorless, and highly flammable; thus appropriate safety protocol implementation and monitoring are essential. Highly sensitive hydrogen leak detection and surveillance sensor systems are needed; additionally, the ability to maintain uniformity through repetitive hydrogen sensing is becoming increasingly important. In this report, we detail the fabrication of porous palladium coated conducting polymer (3-carboxylate polypyrrole) nanoparticles (Pd@CPPys) to detect hydrogen gas. The Pd@CPPys are produced by means of facile alkyl functionalization and chemical reduction of a pristine 3-carboxylate polypyrrole nanoparticle-contained palladium precursor (PdCl2) solution. The resulting Pd@CPPy-based sensor electrode exhibits ultrahigh sensitivity (0.1 ppm) and stability toward hydrogen gas at room temperature due to the palladium sensing layer.Hydrogen, a clean-burning fuel, is of key importance to various industrial applications, including fuel cells and in the aerospace and automotive industries. However, hydrogen gas is odorless, colorless, and highly flammable; thus appropriate safety protocol implementation and monitoring are essential. Highly sensitive hydrogen leak detection and surveillance sensor systems are needed; additionally, the ability to maintain uniformity through repetitive hydrogen sensing is becoming increasingly important. In this report, we detail the fabrication of porous palladium coated conducting polymer (3-carboxylate polypyrrole) nanoparticles (Pd@CPPys) to detect hydrogen gas. The Pd@CPPys are produced by means of facile alkyl functionalization and chemical reduction of a pristine 3-carboxylate polypyrrole nanoparticle-contained palladium precursor (PdCl2) solution. The resulting Pd@CPPy-based sensor electrode exhibits ultrahigh sensitivity (0.1 ppm) and stability toward hydrogen gas at room temperature due to the palladium sensing layer. Electronic supplementary information (ESI) available: BET surface area and pore distribution of palladium architectures without CPPyNPs; Hydrogen sensing ability of palladium architectures without CPPyNPs; HR-TEM image of Pd@CPPy_C16 after 100 cycle exposure of H2. See DOI: 10.1039/c5nr06193h

Electrochemical sensor based on gold nanoparticles fabricated molecularly imprinted polymer film at chitosan-platinum nanoparticles/graphene-gold nanoparticles double nanocomposites modified electrode for detection of erythromycin.

PubMed

Lian, Wenjing; Liu, Su; Yu, Jinghua; Xing, Xianrong; Li, Jie; Cui, Min; Huang, Jiadong

2012-01-01

A molecularly imprinted electrochemical sensor was fabricated based on gold electrode decorated by chitosan-platinum nanoparticles (CS-PtNPs) and graphene-gold nanoparticles (GR-AuNPs) nanocomposites for convenient and sensitive determination of erythromycin. The synergistic effects of CS-PtNPs and GR-AuNPs nanocomposites improved the electrochemical response and the sensitivity of the sensor. The molecularly imprinted polymers (MIPs) were prepared by HAuCl(4), 2-mercaptonicotinic acid (MNA) and erythromycin. Erythromycin and MNA were used as template molecule and functional monomer, respectively. They were first assembled on the surface of GR-AuNPs/CS-PtNPs/gold electrode by the formation of Au-S bonds and hydrogen-bonding interactions. Then the MIPs were formed by electropolymerization of HAuCl(4), MNA and erythromycin. The sensor was characterized by cyclic voltammetry (CV), scanning electron microscope (SEM), UV-visible (UV-vis) absorption speactra and amperometry. The linear range of the sensor was from 7.0 × 10(-8)mol/L-9.0 × 10(-5)mol/L, with the limit of detection (LOD) of 2.3 × 10(-8)mol/L (S/N=3). The sensor showed high selectivity, excellent stability and good reproducibility for the determination of erythromycin, and it was successfully applied to the detection of erythromycin in real spiked samples. Copyright © 2012 Elsevier B.V. All rights reserved.

A novel HPLC fluorescence method for the quantification of methylphenidate in human plasma

PubMed Central

Zhu, Hao-Jie; Wang, Jun-Sheng; Patrick, Kennerly S.; Donovan, Jennifer L.; DeVane, C. Lindsay; Markowitz, John S.

2007-01-01

A number of analytical methods have been established to quantify methylphenidate (MPH). However, to date no HPLC methods are applicable to human pharmacokinetic studies without the use of mass spectrometry (MS) detection. We developed a sensitive and reliable HPLC-fluorescence method for the determination of MPH in human plasma using 4-(4,5-diphenyl-1H-imidazol-2-yl) benzoyl chloride (DIB-Cl) as the derivatizing agent. An established GC-MS method was adopted in this study as a comparator assay. MPH was derivatized DIB-Cl, and separated isocratically on a C18 column using a HPLC system with fluorescence detection (λex: 330 nm, λem: 460 nm). The lower limit of determination was found to be 1 ng/mL. A linear calibration curve was obtained over the concentrations ranging from 1 to 80 ng/mL (r=0.998). The relative standard deviations of intra-day and inter-day variations were ≤ 9.10 % and ≤ 7.58 %, respectively. The accuracy ranged between 92.59 % and 103.06 %. The method was successfully applied to the pharmacokinetic study of a subject who received a single oral dose (0.3 mg/kg) of immediate-release MPH and yielded consistent results with that of the GC-MS method. This method is the first HPLC assay with non-MS detection providing sufficient reliability and sensitivity for both pre-clinical and clinical studies of MPH. PMID:17804308

Flow-injection chemiluminescence analysis for sensitive determination of atenolol using cadmium sulfide quantum dots

NASA Astrophysics Data System (ADS)

Khataee, Alireza; Lotfi, Roya; Hasanzadeh, Aliyeh; Iranifam, Mortaza; Joo, Sang Woo

2016-03-01

A sensitive, rapid and simple flow-injection chemiluminescence (CL) system based on the light emitted from KMnO4-cadmium sulfide quantum dots (CdS QDs) reaction in the presence of cetyltrimethylammonium bromide (CTAB) in acidic medium was developed as a CL probe for the sensitive determination of atenolol. Optical and structural features of CdS QDs capped with L-cysteine, which synthesized via hydrothermal approach, were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and UV-Vis spectroscopy. The CL intensity of KMnO4-CdS QDs-CTAB was remarkably enhanced in the presence of trace level of atenolol. Under optimum experimental conditions, there is a linear relationship between the increase in CL intensity of KMnO4-CdS QDs-CTAB system and atenolol concentration in a range of 0.001 to 4.0 mg L- 1 and 4.0 to 18.0 mg L- 1, with a detection limit (3σ) of 0.0010 mg L- 1. A possible mechanism for KMnO4-CdS QDs-CTAB-atenolol CL reaction is proposed. To prove the practical application of the KMnO4-CdS QDs-CTAB CL method, the method was applied for the determination of atenolol in spiked environmental water samples and commercial pharmaceutical formulation. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) technique was utilized for determination of atenolol. Figure S2. Optimization of the CL reaction conditions: (a) effect of KMnO4 concentration. Conditions: the concentrations of H2SO4, CdS QDs and atenolol were 1 mol L-1, 0.35 mol L-1, and 4.0 mg L-1, respectively; (b) effect of acidic media. Conditions: the concentrations of KMnO4 was 0.04 mmol L-1, other conditions were as in (a); (c) effect of CdS QDs concentration. Conditions: H2SO4 concentration was 1.0 mol L-1, other conditions were as in (b), and (d) effect of CTAB concentration. Conditions: CdS QDs concentration was 0.35 mmol L-1, other conditions were as in (c). Figure S3. UV-Vis absorption spectra of KMnO4-CdS QDs-atenolol CL system, recorded at different time intervals after their mixing. Conditions: the concentrations of KMnO4, CdS QDs, H2SO4 and atenolol were 0.04 mmol L-1, 0.35 mmol L-1, 1.0 mol L-1 and 4.0 mg L-1, respectively.

Enhancing the chemiluminescence intensity of a KMnO4 formaldehyde system for estimating the total phenolic content in honey samples using a novel nanodroplet mixing approach in a microfluidics platform.

PubMed

Al Lawati, Haider A J; Al Mughairy, Baqia; Al Lawati, Iman; Suliman, FakhrEldin O

2018-04-30

A novel mixing approach was utilized with a highly sensitive chemiluminescence (CL) method to determine the total phenolic content (TPC) in honey samples using an acidic potassium permanganate-formaldehyde system. The mixing approach was based on exploiting the mixing efficiency of nanodroplets generated in a microfluidic platform. Careful optimization of the instrument setup and various experimental conditions were employed to obtain excellent sensitivity. The mixing efficiency of the droplets was compared with the CL signal intensity obtained using the common serpentine chip design, with both approaches using at a total flow rate of 15 μl min -1 ; the results showed that the nanodroplets provided 600% higher CL signal intensity at this low flow rate. Using the optimum conditions, calibration equations, limits of detection (LOD) and limits of quantification (LOQ) for gallic acid (GA), caffeic acid (CA), kaempferol (KAM), quercetin (QRC) and catechin (CAT) were obtained. The LOD ranged from 6.2 ppb for CA to 11.0 ppb for QRC. Finally, the method was applied for the determination of TPC in several local and commercial honey samples. Copyright © 2018 John Wiley & Sons, Ltd.

Thermochemical properties of nanometer CL-20 and PETN fabricated using a mechanical milling method

NASA Astrophysics Data System (ADS)

Song, Xiaolan; Wang, Yi; An, Chongwei

2018-06-01

2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and pentaerythritol tetranitrate (PETN), with mean sizes of 73.8 nm and 267.7 nm, respectively, were fabricated on a high-energy ball-mill. Scanning electron microscope (SEM) analysis was used to image the micron-scale morphology of nano-explosives, and the particle size distribution was calculated using the statistics of individual particle sizes obtained from the SEM images. Analyses, such as X-ray diffractometer (XRD), infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS), were also used to confirm whether the crystal phase, molecular structure, and surface elements changed after a long-term milling process. The results were as expected. Thermal analysis was performed at different heating rates. Parameters, such as the activation energy (ES), activation enthalpy (ΔH≠), activation free energy (ΔG≠), activation entropy (ΔS≠), and critical temperature of thermal explosion (Tb), were calculated to determine the decomposition courses of the explosives. Moreover, the thermal decomposition mechanisms of nano CL-20 and nano PETN were investigated using thermal-infrared spectrometry online (DSC-IR) analysis, by which their gas products were also detected. The results indicated that nano CL-20 decomposed to CO2 and N2O and that nano PETN decayed to NO2, which implied a remarkable difference between the decomposition mechanisms of the two explosives. In addition, the mechanical sensitivities of CL-20 and PETN were tested, and the results revealed that nano-explosives were more insensitive than raw ones, and the possible mechanism for this was discussed. Thermal sensitivity was also investigated with a 5 s bursting point test, from which the 5 s bursting point (T5s) and the activation of the deflagration were obtained.

New Data On The Cathodoluminescence Of White Marbles: Interpretation Of Peaks And Relationships To Weathering

NASA Astrophysics Data System (ADS)

Garcia-Guinea, J.; Crespo-Feo, E.; Correcher, V.; Iordanidis, A.; Charalampides, G.; Karamitrou-Mentessidi, G.

This work focus on the Thermoluminescence (TL), the Spatially Resolved Spectral Cathodoluminescence (CL) and Raman spectroscopy (Raman) of white marble specimens collected from the archaeological park of Aiani (Greece) and from patterns of Iceland calcite and Macael marble for comparison purposes. The spectra CL were measured with a high sensitivity cathodoluminescence spectrometer MonoCL3 of Gatan (UK) attached to an FEI-ESEM microscope (CL-ESEM). The experimental set of spectra CL curves of Aiani white marbles suggest that the blue band is more resistant to weathering in comparison with the red band which drops down easily under weathering. The comparison among CL spectra of CaCO3 patterns give a slight difference between the small 330 nm peak, detected in marble and not observed in the monocrystal pattern of Iceland calcite. The Backscattering Electron Dispersed (BSED) images of the white marble are similar to the CL monochromatic plots at 330 nm which highlight the surfaces with remarkable clarity, suggesting a CL emission-defect associated to the marble crystal interfaces, such as protons or hydroxyls. Conversely, the 395 nm monochromatic mapping depicts a CL image emitting from bulk and not from interfaces attributable to point defects or cationic activators in Ca2+ positions. The blue band of the spectra luminescence of marble is composed by several peaks associated to very different types of luminescent defects. This statement is not inconsequential since in archaeological TL dating of marbles the regenerated luminescence in the blue region of the spectrum is a serious difficulty and further research on this topic is necessary.

Evaluation of sampling technique and transport media for the diagnostics of adenoviral eye infections. Adenovirus sampling and transport.

PubMed

Wölfel, Roman; Pfeffer, Martin; Essbauer, Sandra; Nerkelun, Sylke; Dobler, Gerhard

2006-11-01

Human adenoviruses (HAdV) may cause pharyngoconjunctival fever, follicular conjunctivitis or epidemic keratoconjunctivitis (EKC). Especially, outbreaks of the latter may lead to severe economic losses when preventive measures are implemented too late. Thus, a safe sampling method, proper specimen transport conditions and a fast and sensitive diagnostic technique is mandatory. Two commercially available virus transport systems (VTS) were compared with two NaCl-moisturised sampling devices, one of which comprises Dacron-tipped plastic-shafted swabs and the other a cotton-tipped wood-shafted swab, available in most ophthalmologists' offices. Downstream methods for specific detection of HAdV included direct immunofluorescence assay (IFA) of conjunctival swabs, virus isolation by cell culture and quantitative real-time polymerase chain reaction (qPCR). Furthermore, the influence of application of local anaesthetics prior to swabbing on subsequent detection of HAdV was investigated. Application of local anaesthetics had a positive influence on the amount of swabbed cells, thus increasing the chance of obtaining positive results by IFA. Neither isolation of HAdV by cell culture nor by qPCR was negatively influenced by this pretreatment. Surprisingly, both commercially available VTS performed significantly worse than the NaCl-moisturised swabs. This was shown with regard to virus recovery rates in cell culture as well as viral genome copy numbers in the qPCR. Based on our results, the following recommendations are provided to improve sampling, transport and diagnostic techniques regarding conjunctival swabs for diagnosis of human adenovirus infection: (1) application of local anaesthetics, (2) NaCl-moisturised VTS for shipment of specimens, and (3) detection of HAdV by qPCR. The latter method proved to be superior to virus isolation by cell culture, including subsequent identification by IFA, because it is faster, more sensitive and allows simultaneous handling of a number of samples. Hence, countermeasures to prevent further virus spread in an outbreak situation can be implemented earlier, thus reducing the number of subsequent adenoviral infections.

Modeled Martian subsurface elemental composition measurements with the Probing In situ with Neutron and Gamma ray instrument: Gamma and Neutron Measurements on Mars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nowicki, Suzanne F.; Evans, Larry G.; Starr, Richard D.

Here, the Probing In situ with Neutrons and Gamma rays (PING) instrument is an innovative application of active neutron-induced gamma-ray technology. The objective of PING is to measure the elemental composition of the Martian regolith. As part 2 of a two-part submission, this manuscript presents PING's sensitivities as a function of the Martian regolith depth and PING's uncertainties in the measurements as a function of observation time in passive and active mode. Part 1 of our submission models the associated regolith types. The modeled sensitivities show that in PING's active mode, where both a Pulsed Neutron Generator (PNG) and amore » Gamma-Ray Spectrometer (GRS) are used, PING can interrogate the material below the rover to about 20 cm due to the penetrating nature of the high-energy neutrons and the resulting secondary gamma rays observed with the GRS. PING is capable of identifying most major and minor rock-forming elements, including H, O, Na, Mn, Mg, Al, Si, P, S, Cl, Cr, K, Ca, Ti, Fe and Th. The modeled uncertainties show that PING's use of a PNG reduces the required observation times by an order of magnitude over a passive operating mode where the PNG is turned off. While the active mode allows for more complete elemental inventories with higher sensitivity, the gamma-ray signatures of some elements are strong enough to detect in passive mode. We show that PING can detect changes in key marker elements and make thermal neutron measurements in about 1 minute that are sensitive to H and Cl.« less

Modeled Martian subsurface elemental composition measurements with the Probing In situ with Neutron and Gamma ray instrument: Gamma and Neutron Measurements on Mars

DOE PAGES

Nowicki, Suzanne F.; Evans, Larry G.; Starr, Richard D.; ...

2017-02-01

Here, the Probing In situ with Neutrons and Gamma rays (PING) instrument is an innovative application of active neutron-induced gamma-ray technology. The objective of PING is to measure the elemental composition of the Martian regolith. As part 2 of a two-part submission, this manuscript presents PING's sensitivities as a function of the Martian regolith depth and PING's uncertainties in the measurements as a function of observation time in passive and active mode. Part 1 of our submission models the associated regolith types. The modeled sensitivities show that in PING's active mode, where both a Pulsed Neutron Generator (PNG) and amore » Gamma-Ray Spectrometer (GRS) are used, PING can interrogate the material below the rover to about 20 cm due to the penetrating nature of the high-energy neutrons and the resulting secondary gamma rays observed with the GRS. PING is capable of identifying most major and minor rock-forming elements, including H, O, Na, Mn, Mg, Al, Si, P, S, Cl, Cr, K, Ca, Ti, Fe and Th. The modeled uncertainties show that PING's use of a PNG reduces the required observation times by an order of magnitude over a passive operating mode where the PNG is turned off. While the active mode allows for more complete elemental inventories with higher sensitivity, the gamma-ray signatures of some elements are strong enough to detect in passive mode. We show that PING can detect changes in key marker elements and make thermal neutron measurements in about 1 minute that are sensitive to H and Cl.« less

Spectroscopic studies on the lanthanide sensitized luminescence and chemiluminescence properties of fluoroquinolone with different structure.

PubMed

Sun, Chunyan; Ping, Hong; Zhang, Minwei; Li, Hongkun; Guan, Fengrui

2011-11-01

Lanthanide sensitized luminescence and chemiluminescence (CL) are of great importance because of the unique spectral properties, such as long lifetime, large Stokes shifts, and narrow emission bands characteristic to lanthanide ions (Ln(3+)). With the fluoroquinolone (FQ) compounds including enoxacin (ENX), norfloxacin (NFLX), lomefloxacin (LMFX), fleroxacin (FLRX), ofloxacin (OFLX), rufloxacin (RFX), gatifloxacin (GFLX) and sparfloxacin (SPFX), the luminescence and CL properties of Tb(3+)-FQ and Eu(3+)-FQ complexes have been investigated in this contribution. Ce(4+)-SO(3)(2-) in acidic conditions was taken as the CL system and sensitized CL intensities of Tb(3+)-FQ and Eu(3+)-FQ complexes were determined by flow-injection analysis. The luminescence and CL spectra of Tb(3+)-FQ complexes show characteristic peaks of Tb(3+) at 490 nm, 545 nm, 585 nm and 620 nm. Complexes of Tb(3+)-ENX, Tb(3+)-NFLX, Tb(3+)-LMFX and Tb(3+)-FLRX display relatively strong emission intensity compared with Tb(3+)-OFLX, Tb(3+)-RFX, Tb(3+)-GFLX and Tb(3+)-SPFX. Quite weak peaks with unique characters of Eu(3+) at 590 nm and 617 nm appear in the luminescence and CL spectra of Eu(3+)-ENX, but no notable sensitized luminescence and CL of Eu(3+) could be observed when Eu(3+) is added into other FQ. The distinct differences on emission intensity of Tb(3+)-FQ and Eu(3+)-FQ might originate from the different energy gap between the triplet levels of FQ and the excited levels of the Ln(3+). The different sensitized luminescence and CL signals among Tb(3+)-FQ complexes could be attributed to different optical properties and substituents of these FQ compounds. The detailed mechanism involved in the luminescence and CL properties of Tb(3+)-FQ and Eu(3+)-FQ complexes has been investigated by analyzing the luminescence and CL spectra, quantum yields, and theoretical calculation results. Copyright © 2011 Elsevier B.V. All rights reserved.

Comparative assessment of recombinant and native immunogenic forms of Fasciola hepatica proteins for serodiagnosis of sheep fasciolosis.

PubMed

Mokhtarian, Kobra; Meamar, Ahmad Reza; Khoshmirsafa, Majid; Razmjou, Elham; Masoori, Leila; Khanmohammadi, Majid; Akhlaghi, Lame; Falak, Reza

2018-01-01

Laboratory diagnosis of sheep fasciolosis is commonly performed by coprological examinations; however, this method may lead to false negative results during the acute phase of the infection. Furthermore, the poor sensitivity of coprological methods is considered to be a paradox in the chronic phase of the infection. In this study, we compared the immunoreactivity of native and recombinant forms of Fasciola hepatica excretory/secretory antigens and determined their capabilities for the development of F. hepatica-specific immunoassays. Immunoreactivity and specificity of recombinant and native forms of F. hepatica antigens, including fatty acid binding protein (FABP), glutathione-S-transferase (GST), and cathepsin L-1 (CL1), in parallel with native forms of FABP and GST, were studied for serodiagnosis of the chronic form of sheep fasciolosis, individually or in combination with each other by enzyme-linked immunosorbent assays (ELISA). The correlation of the findings was assessed by receiver-operator characteristic (ROC); furthermore, the specificity and sensitivity were assessed by Youden's J. Serologic cross-reactivity was evaluated using samples from healthy sheep (n = 40), Fasciola-infected sheep (n = 30), and sheep with other parasitic infections (n = 43). The FABPs were determined to be greater than 95% sensitive for F. hepatica serodiagnosis. The most desirable diagnostic recombinant antigen was rCL1, which showed 100% sensitivity and 97% specificity in ELISA and was capable of discriminating the positive and negative samples by maximum Youden's J results. We conclude that rCL1 can be used for routine serodiagnosis of chronic fasciolosis. Thus, it could be advantageous in development of immunoassays for screening of ovine herds in fasciolosis-endemic areas and as a reliable agent for detection of fasciolosis in non-endemic regions.

A flow method based on solvent extraction coupled on-line to a reversed micellar mediated chemiluminescence detection for selective determination of gold(III) and gallium(III) in water and industrial samples.

PubMed

Hasanin, Tamer H A; Okamoto, Yasuaki; Fujiwara, Terufumi

2016-02-01

A rapid and sensitive flow method, based on the combination of on-line solvent extraction with reversed micellar mediated chemiluminescence (CL) detection using rhodamine B (RB), was investigated for the selective determination of Au(III) and Ga(III) in aqueous solutions. 2.0 M HCl was the optimum for extracting Au(III) while a 5.0M HCl solution containing 2.5M LiCl was selected as an optimum acidic medium for extraction of Ga(III). The Au(III) and Ga(III) chloro-complex anions were extracted from the above aqueous acidic solutions into toluene as their ion-pair complexes with the protonated RBH(+) ion followed by membrane phase separation in a flow system. In a flow cell of a detector, the extract was mixed with the reversed micellar solution of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water (1.0M HCl) containing 0.10 M cerium(IV) and 0.05 M lithium sulfate. Then uptake of the ion-pair by the CTAC reversed micelles and the subsequent CL oxidation of RB with Ce(IV) occurred easily and the CL signals produced were recorded. Using a flow injection system, a detection limit (DL) of 0.4 μM Au(III) and 0.6 μM Ga(III), and linear calibration graphs with dynamic ranges from the respective DLs to 10 μM for Au(III) and Ga(III) were obtained under the optimized experimental conditions. The relative standard deviations (n=6) obtained at 2.0 µM Au(III) and 4.0 µM Ga(III) were 3.0% and 2.4%, respectively. The presented CL methodology has been applied for the determination of Au(III) and Ga(III) in water and industrial samples with satisfactory results. Copyright © 2015 Elsevier B.V. All rights reserved.

Peroxyoxalate chemiluminescence detection of condensates of malondialdehyde with thiobarbituric acids using a flow system.

PubMed

Nakashima, K; Nagata, M; Takahashi, M; Akiyama, S

1992-01-01

The peroxyoxalate chemiluminescence(CL) detection method for the evaluation of the CL intensity of malondialdehyde(MDA) condensates with seven 2-thiobarbituric acid derivatives is described. The method consists of a flow injection technique together with a CL detection system using bis(2,4,6-trichlorophenyl) oxalate(TCPO) and hydrogen peroxide as chemiluminogenic reagents. Linear correlations between CL intensity and concentration are obtained for pmol levels of condensates. Among the condensates, 1,3-diethyl-2-thiobarbituric acid(DETBA)-MDA shows the largest CL intensity. High performance liquid chromatography (HPLC)/CL detection of DETBA-MDA and 1,3-diphenyl-2-thiobarbituric acid(DPTBA)-MDA using a mixture of TCPO and hydrogen peroxide in acetonitrile as a postcolumn reagent solution is also described. The detection limits for DETBA-MDA and DPTBA-MDA are 20 and 200 fmol, respectively, per 20 microL injection at a signal-to-noise ratio of 2. This HPLC/CL detection system was applied to the determination of MDA in rat brains by using DETBA as a fluorescent derivatizing reagent.

Purification of high-molecular-weight subfraction from porcine skin inhibiting proliferation of A431 human carcinoma epidermoid cells.

PubMed

Belova, O V; Sergienko, V I; Arion, V Ya; Lukanidina, T A; Moskvina, S N; Zimina, I V; Borisenko, G G; Lutsenko, G V; Grechikhina, M V; Kovaleva, E V; Klyuchnikova, Zh I

2014-07-01

Subfraction with a molecular weight >250 kDa isolated from porcine skin and inhibiting the proliferation of A431 human carcinoma epidermoid cells was purified by DEAE 32 anion exchange chromatography with NaCl concentration step-gradient. The effects of the initial subfraction and fractions obtained by separation in DEAE 32 on the proliferation of A431 human carcinoma epidermoid cells were studied in vitro in two tests (MTT and fluorescent test). The more sensitive fluorescent test showed the highest inhibitory activity of fraction No. 2 released from the column at 0.15 M NaCl. One major protein component and a series of minor protein components were detected in this fraction by vertical PAAG-SDS electrophoresis.

Orderly arranged fluorescence dyes as a highly efficient chemiluminescence resonance energy transfer probe for peroxynitrite.

PubMed

Wang, Zhihua; Teng, Xu; Lu, Chao

2015-03-17

Chemiluminescence (CL) probes for reactive oxygen species (ROS) are commonly based on a redox reaction between a CL reagent and ROS, leading to poor selectivity toward a specific ROS. The energy-matching rules in the chemiluminescence resonance energy transfer (CRET) process between a specific ROS donor and a suitable fluorescence dye acceptor is a promising method for the selective detection of ROS. Nevertheless, higher concentrations of fluorescence dyes can lead to the intractable aggregation-caused quenching effect, decreasing the CRET efficiency. In this report, we fabricated an orderly arranged structure of calcein-sodium dodecyl sulfate (SDS) molecules to improve the CRET efficiency between ONOOH* donor and calcein acceptor. Such orderly arranged calcein-SDS composites can distinguish peroxynitrite (ONOO(-)) from a variety of other ROS owing to the energy matching in the CRET process between ONOOH* donor and calcein acceptor. Under the optimal experimental conditions, ONOO(-) could be assayed in the range of 1.0-20.0 μM, and the detection limit for ONOO(-) [signal-to-noise ratio (S/N) = 3] was 0.3 μM. The proposed strategy has been successfully applied in both detecting ONOO(-) in cancer mouse plasma samples and monitoring the generation of ONOO(-) from 3-morpholinosydnonimine (SIN-1). Recoveries from cancer mouse plasma samples were in the range of 96-105%. The success of this work provides a unique opportunity to develop a CL tool to monitor ONOO(-) with high selectivity in a specific manner. Improvement of selectivity and sensitivity of CL probes holds great promise as a strategy for developing a wide range of probes for various ROS by tuning the types of fluorescence dyes.

A chemiluminescence biosensor based on the adsorption recognition function between Fe3O4@SiO2@GO polymers and DNA for ultrasensitive detection of DNA.

PubMed

Sun, Yuanling; Li, Jianbo; Wang, Yanhui; Ding, Chaofan; Lin, Yanna; Sun, Weiyan; Luo, Chuannan

2017-05-05

In this work, a chemiluminescence (CL) biosensor was prepared for ultrasensitive determination of deoxyribonucleic acid (DNA) based on the adsorption recognition function between core-shell Fe 3 O 4 @SiO 2 - graphene oxide (Fe 3 O 4 @SiO 2 @GO) polymers and DNA. The Fe 3 O 4 @SiO 2 @GO polymers were composed by GO and magnetite nanoparticles. And the core-shell polymers were confirmed by Scanning Electron Microscope (SEM), X-Ray Powder Diffraction (XRD) and Fourier Transform Infrared (FTIR). Then Fe 3 O 4 @SiO 2 @GO was modified by DNA. Based on the principle of complementary base, Fe 3 O 4 @SiO 2 @GO-DNA was introduced to the CL system and the selectivity, sensitivity of DNA detection was significantly improved. The adsorption properties of Fe 3 O 4 @SiO 2 @GO to DNA were researched through the adsorption equilibrium, adsorption kinetic and thermodynamics. Under optimized CL conditions, DNA could be assayed with the linear concentration range of 5.0×10 -12 -2.5×10 -11 mol/L. The detection limit was 1.7×10 -12 mol/L (3δ) and the relative standard deviation (RSD) was 3.1%. The biosensor was finally used for the determination of DNA in laboratory samples and recoveries ranged from 99% to 103%. The satisfactory results revealed the potential application of Fe 3 O 4 @SiO 2 @GO-DNA-CL biosensor in the diagnosis and the treatment of human genetic diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

Demonstration and Validation of a Portable Raman Sensor for In-Situ Detection and Monitoring of Perchlorate (ClO 4 -)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatzinger, Paul B.; Eres, Gyula; Gu, Baohua

Costs for environmental analysis and monitoring are increasing at a rapid rate and represent a significant percentage of the total and future remedial expenses at many U.S. Department of Defense (DoD) contaminated sites. It has been reported that about 30 to 40% of the remediation budget is usually spent on long-term monitoring (LTM), of which a large percentage represents laboratory analytical costs. Energetics such as perchlorate (ClO 4 -) are among the most frequently detected contaminants in groundwater and surface water at or near military installations due to their persistence and mobility. Currently, the standard protocol entails collecting samples inmore » the field, packaging them, and shipping them overnight to a designated laboratory for analysis. This process requires significant sample preparation and handling, and analytical results may not be available for several days to weeks. In this project, we developed and demonstrated a portable Raman sensor based on surface enhanced Raman scattering (SERS) technology to detect ClO 4 - in contaminated water. We summarize major accomplishments as follows: • A SERS sensor based on elevated gold (Au) nano-ellipse dimer architectures was designed and developed for ClO 4 - with a detection limit of ~10 -6 M (or 100 μg/L); The performance of these sensors was evaluated and optimized through variation of their geometric characteristics (i.e., dimer aspect ratio, dimer separation, etc.). • Large-scale commercial production of SERS substrate sensors via nanoimprinting by Nanova Inc. and Nanoimprint lithography (NIL) technology was successfully demonstrated. This is a substantial step forward toward the commercialization of the SERS sensors and may potentially lead to significantly reduced fabrication costs of SERS substrates. • Commercially produced SERS sensors were demonstrated to detect ClO 4 - at levels above 10 -6 M using a portable Raman analyzer. The performance of the commercial SERS sensors for ClO 4 - detection in the presence and absence of interferences was determined for a series of standard solutions. Sulfate (SO 4 2-) was found to exhibit the greatest interference for the anions tested, which included Cl-, NO 3 -, and SO 4 2-. • Field demonstration of the portable Raman sensor with commercially produced SERS substrates was completed at two Department of Defense (DoD) sites; twice at the Indian Head Naval Surface Warfare Center, Indian Head, MD, and once at Redstone Arsenal, Huntsville, AL. Multiple wells were sampled at both DoD sites, where a standard addition method was employed using the sensor to determine the ClO 4 -4 - and possibly other energetics that are both important for environmental monitoring and of interest for national security. However, we point out that SERS technology is also prone to interferences due to its sensitivity and responses to other ionic species, such as NO 3 -, SO 4 2-, and dissolved organics or co-contaminants present in the groundwater, which could potentially mask the SERS signal of the target analyte (i.e., ClO 4 -). As such, SERS analysis was subject to significant variations (e.g., ±20% or more), and its detection limit for ClO 4 --8 M) and was substantially higher than what we anticipated from laboratory studies. However, despite these complications, the portable Raman sensor developed in this project could be used as a rapid screening tool for ClO 4 - at concentrations above 10 -6 M. Future studies are warranted to further develop the technology and to optimize its performance, and eventually to bring the technology to the market. With additional development and demonstration, the sensor has the potential to reduce analytical costs by eliminating shipping and typical costs associated with laboratory analysis. A cost savings of 30–45% may be realized during a typical sampling event and, more importantly, the technology could allow rapid turn-around of information to decision makers for site characterization and remediation.« less

Facile and sensitive determination of N-nitrosamines in food samples by high-performance liquid chromatography via combining fluorescent labeling with dispersive liquid-liquid microextraction.

PubMed

Lu, Shuaimin; Wu, Di; Li, Guoliang; Lv, Zhengxian; Gong, Peiwei; Xia, Lian; Sun, Zhiwei; Chen, Guang; Chen, Xuefeng; You, Jinmao; Wu, Yongning

2017-11-01

The intake of N-nitrosamines (NAs) from foodstuffs is considered to be an important influence factor for several cancers. But the rapid and sensitive screening of NAs remains a challenge in the field of food safety. Inspired by that, a sensitive and rapid method was demonstrated for determination of five NAs (Nitrosopyrrolidine, Nitrosodimethylamine, Nitrosodiethylamine, Nitrosodipropylamine and Nitrosodibutylamine) using dispersive liquid-liquid microextraction (DLLME) followed by high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The NAs were firstly denitrosated and labeled by 2-(11H-benzo[a]carbazol-11-yl) ethyl carbonochloridate (BCEC-Cl) and finally enriched by DLLME. Furthermore, the main DLLME conditions were optimized systematically. Under the optimal conditions, satisfactory limits of detection (LODs) were obtained with a range of 0.01-0.07ngg -1 , which were significantly lower than the reported methods. The developed method showed many merits including rapidity, simplicity, high sensitivity and excellent selectivity, which shows a broad prospect in food safety analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chlorinated metronidazole as a promising alternative for treating trichomoniasis.

PubMed

Chacon, M O; Fonseca, T H S; Oliveira, S B V; Alacoque, M A; Franco, L L; Tagliati, C A; Cassali, G D; Campos-Mota, G P; Alves, R J; Capettini, L S A; Gomes, Maria Aparecida

2018-05-01

Trichomoniasis is the most common non-viral, sexually transmitted infection affecting humans worldwide. The main treatment for trichomoniasis is metronidazole (MTZ). However, adverse effects and reports of resistance have stimulated the development of therapeutic alternatives. The ease of manipulation of the side chains of MTZ coupled with its safety makes this molecule attractive for the development of new drugs. In this context, we evaluated the activity of the chlorinated MTZ derivative, MTZ-Cl, on sensitive and resistant strains of Trichomonas vaginalis. MTZ-Cl presented a remarkable activity against both sensitive and resistant strains. In vitro and in vivo toxicity assays indicated that the new molecule is safe for future clinical trials. Furthermore, we noticed different rates of free radical production between the sensitive and resistant strains. MTZ-Cl induced a higher release of nitric oxide (NO, ~ 9000 a.u.) by both sensitive and resistant strains. However, the sensitive strain produced a greater amount of H 2 O 2 (~ 1,800,000 a.u.) and superoxide radicals (~ 350,000 a.u.) in the presence of MTZ. In the resistant strain, production of these radicals was more prominent when MTZ-Cl was used. Collectively, these results suggest that NO is an important molecule in the trichomonacidal activity against resistant and sensitive strains, suggesting an alternative pathway for MTZ-Cl activation. We highlight the high trichomonacidal potential of MTZ-Cl, improving the effectiveness of treatment and reducing side effects. In addition, MTZ-Cl is derived from a well-established drug on the world market that presents low toxicity to human cells, suggesting its safety to proceed with future clinical trials.

Influence of TiCl4 post-treatment condition on TiO2 electrode for enhancement photovoltaic efficiency of dye-sensitized solar cells.

PubMed

Eom, Tae Sung; Kim, Kyung Hwan; Bark, Chung Wung; Choi, Hyung Wook

2014-10-01

Titanium tetrachloride (TiCl4) treatment processed by chemical bath deposition is usually adopted as pre- and post-treatment for nanocrystalline titanium dioxide (TiO2) film deposition in the dye-sensitized solar cells (DSSCs) technology. TiCl4 post-treatment is a widely known method capable of improving the performance of dye-sensitized solar cells. In this work, the effect of TiCl4 post-treatment on the TiO2 electrode is proposed and compared to the untreated film. A TiO2 passivating layer was deposited on FTO glass by RF magnetron sputtering. The TiO2 sol prepared sol-gel method, nanoporous TiO2 upper layer was deposited by screen printing method on the passivating layer. TiCl4 post-treatment was deposited on the substrate by hydrolysis of TiCl4 aqueous solution. Crystalline structure was adjusted by various TiCl4 concentration and dipping time: 20 mM-150 mM and 30 min-120 min. The conversion efficiency was measured by solar simulator (100 mW/cm2). The dye-sensitized solar cell using TiCl4 post-treatment was measured the maximum conversion efficiency of 5.04% due to electron transport effectively. As a result, the DSSCs based on TiCl4 post-treatment showed better photovoltaic performance than cells made purely of TiO2 nanoparticles. The relative DSSCs devices are characterized in terms of short circuit current density, open circuit voltage, fill factor, conversion efficiency.

Laser-induced fluorescence detection strategies for sodium atoms and compounds in high-pressure combustors

NASA Technical Reports Server (NTRS)

Weiland, Karen J. R.; Wise, Michael L.; Smith, Gregory P.

1993-01-01

A variety of laser-induced fluorescence schemes were examined experimentally in atmospheric pressure flames to determine their use for sodium atom and salt detection in high-pressure, optically thick environments. Collisional energy transfer plays a large role in fluorescence detection. Optimum sensitivity, at the parts in 10 exp 9 level for a single laser pulse, was obtained with the excitation of the 4p-3s transition at 330 nm and the detection of the 3d-3p fluorescence at 818 nm. Fluorescence loss processes, such as ionization and amplified spontaneous emission, were examined. A new laser-induced atomization/laser-induced fluorescence detection technique was demonstrated for NaOH and NaCl. A 248-nm excimer laser photodissociates the salt molecules present in the seeded flames prior to atom detection by laser-induced fluorescence.

A sensitive biomarker for the detection of aquatic contamination based on behavioral assays using zebrafish larvae.

PubMed

Nüßer, Leonie K; Skulovich, Olya; Hartmann, Sarah; Seiler, Thomas-Benjamin; Cofalla, Catrina; Schuettrumpf, Holger; Hollert, Henner; Salomons, Elad; Ostfeld, Avi

2016-11-01

An effective biological early warning system for the detection of water contamination should employ undemanding species that rapidly react to the presence of contaminants in their environment. The demonstrated reaction should be comprehensible and unambiguously evidential of the contamination event. This study utilized 96h post fertilization zebrafish larvae and tested their behavioral response to acute exposure to low concentrations of cadmium chloride (CdCl2) (5.0, 2.5, 1.25, 0.625mg/L) and permethrin (0.05, 0.029, 0.017, 0.01μg/L). We hypothesize that the number of larvae that show advanced trajectories in a group corresponds with water contamination, as the latter triggers avoidance behavior in the organisms. The proportion of advanced trajectories in the control and treated groups during the first minute of darkness was designated as a segregation parameter. It was parametrized and a threshold value was set using one CdCl2 trial and then applied to the remaining CdCl2 and permethrin replicates. For all cases, the method allowed distinguishing between the control and treated groups within two cycles of light: dark. The calculated parameter was statistically significantly different between the treated and control groups, except for the lowest CdCl2 concentration (0.625mg/L) in one replicate. This proof-of-concept study shows the potential of the proposed methodology for utilization as part of a multispecies biomonitoring system. Copyright © 2016 Elsevier Inc. All rights reserved.

Ultrasound Current Source Density Imaging in live rabbit hearts using clinical intracardiac catheter

NASA Astrophysics Data System (ADS)

Li, Qian

Ultrasound Current Source Density Imaging (UCSDI) is a noninvasive modality for mapping electrical activities in the body (brain and heart) in 4-dimensions (space + time). Conventional cardiac mapping technologies for guiding the radiofrequency ablation procedure for treatment of cardiac arrhythmias have certain limitations. UCSDI can potentially overcome these limitations and enhance the electrophysiology mapping of the heart. UCSDI exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity. When an ultrasound beam intersects a current path in a material, the local resistivity of the material is modulated by the ultrasonic pressure, and a change in voltage signal can be detected based on Ohm's Law. The degree of modulation is determined by the AE interaction constant K. K is a fundamental property of any type of material, and directly affects the amplitude of the AE signal detected in UCSDI. UCSDI requires detecting a small AE signal associated with electrocardiogram. So sensitivity becomes a major challenge for transferring UCSDI to the clinic. This dissertation will determine the limits of sensitivity and resolution for UCSDI, balancing the tradeoff between them by finding the optimal parameters for electrical cardiac mapping, and finally test the optimized system in a realistic setting. This work begins by describing a technique for measuring K, the AE interaction constant, in ionic solution and biological tissue, and reporting the value of K in excised rabbit cardiac tissue for the first time. K was found to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart tissue, K was determined to be 0.041 +/- 0.012 %/MPa, similar to the measurement of K in physiologic saline: 0.034 +/- 0.003 %/MPa. Next, this dissertation investigates the sensitivity limit of UCSDI by quantifying the relation between the recording electrode distance and the measured AE signal amplitude in gel phantoms and excised porcine heart tissue using a clinical intracardiac catheter. Sensitivity of UCSDI with catheter was 4.7 microV/mA (R2 = 0.999) in cylindrical gel (0.9% NaCl), and 3.2 microV/mA (R2 = 0.92) in porcine heart tissue. The AE signal was detectable more than 25 mm away from the source in cylindrical gel (0.9% NaCl). Effect of transducer properties on UCSDI sensitivity is also investigated using simulation. The optimal ultrasound transducer parameters chosen for cardiac imaging are center frequency = 0.5 MHz and f/number = 1.4. Last but not least, this dissertation shows the result of implementing the optimized ultrasound parameters in live rabbit heart preparation, the comparison of different recording electrode configuration and multichannel UCSDI recording and reconstruction. The AE signal detected using the 0.5 MHz transducer was much stronger (2.99 microV/MPa) than the 1.0 MHz transducer (0.42 microV/MPa). The clinical lasso catheter placed on the epicardium exhibited excellent sensitivity without being too invasive. 3-dimensional cardiac activation maps of the live rabbit heart using only one pair of recording electrodes were also demonstrated for the first time. Cardiac conduction velocity for atrial (1.31 m/s) and apical (0.67 m/s) pacing were calculated based on the activation maps. The future outlook of this dissertation includes integrating UCSDI with 2-dimensional ultrasound transducer array for fast imaging, and developing a multi-modality catheter with 4-dimensional UCSDI, multi-electrode recording and echocardiography capacity.

Thin film organic photodetectors for indirect X-ray detection demonstrating low dose rate sensitivity at low voltage operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Starkenburg, Daken J.; Johns, Paul M.; Baciak, James E.

Here, developments in the field of organic semiconductors have generated organic photodetectors with high quantum efficiency, wide spectral sensitivity, low power consumption, and unique form factors that are flexible and conformable to their substrate shape. In this work, organic photodetectors coupled with inorganic CsI(Tl) scintillators are used to showcase the low dose rate sensitivity that is enabled when high performance organic photodetectors and scintillator crystals are integrated. The detection capability of these organic-inorganic coupled systems to high energy radiation highlights their potential as an alternative to traditional photomultiplier tubes for nuclear spectroscopy applications. When exposed to Bremsstrahlung radiation produced frommore » an X-ray generator, SubPc:C 60, AlPcCl:C 70, and P3HT:PC 61BM thin film photodetectors with active layer thicknesses less than 100 nm show detection of incident radiation at low and no applied bias. Remarkably low dose rates, down to at least 0.28 µGy/s, were detectable with a characteristic linear relationship between exposure rate and photodetector current output. These devices also demonstrate sensitivities as high as 5.37 mC Gy -1 cm -2 when coupled to CsI(Tl). Additionally, as the tube voltage across the X-ray generator was varied, these organic-inorganic systems showed their ability to detect a range of continuous radiation spectra spanning several hundred keV.« less

Thin film organic photodetectors for indirect X-ray detection demonstrating low dose rate sensitivity at low voltage operation

DOE PAGES

Starkenburg, Daken J.; Johns, Paul M.; Baciak, James E.; ...

2017-12-14

Developments in the field of organic semiconductors have generated organic photodetectors with high quantum efficiency, wide spectral sensitivity, low power consumption, and unique form factors that are flexible and conformable to their substrate shape. In this work, organic photodetectors coupled with inorganic CsI(Tl) scintillators are used to showcase the low dose rate sensitivity that is enabled when high performance organic photodetectors and scintillator crystals are integrated. The detection capability of these organic-inorganic coupled systems to high energy radiation highlights their potential as an alternative to traditional photomultiplier tubes for nuclear spectroscopy applications. When exposed to Bremsstrahlung radiation produced from anmore » X-ray generator, SubPc:C60, AlPcCl:C70, and P3HT:PC61BM thin film photodetectors with active layer thicknesses less than 100 nm show detection of incident radiation at low and no applied bias. Remarkably low dose rates, down to at least 0.28 µGy/s, were detectable with a characteristic linear relationship between exposure rate and photodetector current output. These devices also demonstrate sensitivities as high as 5.37 mC Gy-1 cm-2 when coupled to CsI(Tl). Additionally, as the tube voltage across the X-ray generator was varied, these organic-inorganic systems showed their ability to detect a range of continuous radiation spectra spanning several hundred keV.« less

Dependency of plasmon resonance sensitivity of colloidal gold nanoparticles on the identity of surrounding ionic media

NASA Astrophysics Data System (ADS)

Mehrdel, B.; Aziz, A. Abdul

2018-03-01

The plasmon resonance sensitivity of gold nanoparticles (AuNPs) in sodium chloride (NaCl) liquid in near-infrared to the visible spectral region was investigated. The correlation between NaCl concentration and refractive index was analyzed using concentration dependency and Lorenz-Lorenz methods. The first derivative method was applied to the measured absorption spectra to quantitatively evaluate the plasmon resonance sensitivity. To understand the influence of the identity of the surrounding medium on the plasmon resonance sensitivity, experiments were repeated by replacing NaCl with sodium hydroxide (NaOH), followed by phosphate buffered saline (PBS). Experimental results showed that NaCl is the most effective ionic surrounding medium, which gives prominent plasmon resonance response. AuNPs size can have a significant influence on the plasmon resonance sensitivity. For tiny AuNPs (∼10 nm AuNPs), the plasmon resonance is insensitive to the identity of the surrounding medium due to their low cross-section value.

The effect of sodium chloride on molecular mobility in amorphous sucrose detected by phosphorescence from the triplet probe erythrosin B.

PubMed

You, Yumin; Ludescher, Richard D

2008-02-04

Phosphorescence from the triplet probe erythrosin B provides spectroscopic characteristics such as emission energy and lifetime that are specifically sensitive to molecular mobility of the local environment. This study used phosphorescence of erythrosin B to investigate how variation in NaCl content modulated the mobility of the amorphous sucrose matrix over the temperature range from 5 to 100 degrees C. Addition of NaCl increased the emission energy and the energy difference with excitation at the absorption maximum and the red edge, and increased the lifetime by reducing the non-radiative decay rate in the glass as well as in the undercooled liquid in a concentration dependent manner, indicating that NaCl decreased the matrix molecular mobility. Emission energy and lifetime increased with increasing NaCl content up to a maximum at NaCl/sucrose mole ratio of approximately 0.5; above 0.5 mole ratio, the effect of NaCl was less significant and appeared to be opposed by increasing plasticization by residual water. Changes in the width of the distribution of the emission energy and lifetime and variation in the lifetime with excitation and emission wavelength indicated that NaCl increased the spectral heterogeneity and thus increased the extent of dynamic site heterogeneity. These results are consistent with a physical model in which sodium and chloride ions interact with sucrose OH by ion-dipole interactions, forming clusters of less mobile molecules within the matrix.

Luminol-dependent chemiluminescence in antibody-sensitized neutrophils stimulated with protein A-bearing staphylococci.

PubMed

Nishihara, S; Seki, K; Ikigai, H; Masuda, S

1988-01-01

When mouse polymorphonuclear leukocytes (PMNs) sensitized with rabbit antibody to mouse Ehrlich ascites tumor cells were stimulated by Staphylococcus aureus Cowan I cells, a conspicuous luminol-dependent chemiluminescence was observed in the absence of opsonin. The profile of the chemiluminescence (CL) response evoked by staphylococcal cells from antibody-sensitized PMNs had two peaks. An initial peak, observed within 1 min after stimulation, was sharp and high and a second peak, observed about 5 min after stimulation, was low and extended. The CL response of antibody-sensitized PMNs stimulated by S. aureus Cowan I cells was dose-dependently blocked by preincubation with soluble SpA. Cells of a mutant derived from S. aureus Cowan I strain with trace amounts of cell-bound SpA failed to stimulate the antibody-sensitized PMNs to generate the CL response. The antibody-sensitized PMNs were found to phagocytize SpA-bearing S. aureus cells even in the absence of opsonic serum. These results suggest that the observation presented here might provide a useful tool for the investigation of CL response of PMNs.

Polymer microfiber bridging Bi-tapered refractive index sensor based on evanescent field

NASA Astrophysics Data System (ADS)

Lv, Ri-Qing; Wang, Qi; Wang, Bo-Tao; Liu, Yu; Kong, Lingxin

2018-05-01

A PDMS/graphene enhanced PMMA micro optical waveguide sensor is reported in terms of fabrication method and optical characteristics. The micro optical waveguide with a diameter of 6 μm and a length of 800 μm is used as the sensing probe to realize refractive index (RI) measurement suspended in NaCl solutions with different concentrations. Experimental results show that the refractive index sensing sensitivity can reach 2027.97 nm/RIU within the refractive index ranging from 1.3333-1.3426. Research results show that PMMA/graphene micro optical waveguide doped with PDMS is an excellent high sensitive sensing technology in refractive index detection field.

The microchannel x-ray telescope status

NASA Astrophysics Data System (ADS)

Götz, D.; Meuris, A.; Pinsard, F.; Doumayrou, E.; Tourrette, T.; Osborne, J. P.; Willingale, R.; Sykes, J. M.; Pearson, J. F.; Le Duigou, J. M.; Mercier, K.

2016-07-01

We present design status of the Microchannel X-ray Telescope, the focussing X-ray telescope on board the Sino- French SVOM mission dedicated to Gamma-Ray Bursts. Its optical design is based on square micro-pore optics (MPOs) in a Lobster-Eye configuration. The optics will be coupled to a low-noise pnCCD sensitive in the 0.2{10 keV energy range. With an expected point spread function of 4.5 arcmin (FWHM) and an estimated sensitivity adequate to detect all the afterglows of the SVOM GRBs, MXT will be able to provide error boxes smaller than 60 (90% c.l.) arc sec after five minutes of observation.

Application of Liquid Paraffin in Castable CL-20-Based PBX

NASA Astrophysics Data System (ADS)

Zhang, Pu; Guo, Xue-Yong; Zhang, Jing-Yuan; Jiao, Qing-Jie

2014-10-01

Hydroxy-terminated polybutadiene (HTPB)/CL-20 castable explosives plasticized with liquid paraffin were processed successfully by a cast-curing method. The compatibility of liquid paraffin with CL-20, influence of liquid paraffin on CL-20 phase transition, and viscosity of the cast mixture were tested and analyzed. The thermal decomposition characteristics, thermal stability, mechanical sensitivity, and velocity of detonation (VOD) of the HTPB/CL-20 plastic-bonded explosives (PBXs) were also measured. The experimental results showed that liquid paraffin was well compatible with CL-20, and it did not have a distinct effect on the ɛ- to γ-phase transition of CL-20. In addition, the casting mixture was free-flowing with sufficiently low viscosity. When the content of CL-20 is 90% by weight, the measured VOD reached 8,775 m/s (density of 1.78 g/cm3), and the PBXs exhibited moderate mechanical sensitivity and good thermal stability.

Initial Reaction(s) in Biotransformation of CL-20 Is Catalyzed by Salicylate 1-Monooxygenase from Pseudomonas sp. Strain ATCC 29352

PubMed Central

Bhushan, Bharat; Halasz, Annamaria; Spain, Jim C.; Hawari, Jalal

2004-01-01

CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) (C6H6N12O12), a future-generation high-energy explosive, is biodegradable by Pseudomonas sp. strain FA1 and Agrobacterium sp. strain JS71; however, the nature of the enzyme(s) involved in the process was not understood. In the present study, salicylate 1-monooxygenase, a flavin adenine dinucleotide (FAD)-containing purified enzyme from Pseudomonas sp. strain ATCC 29352, biotransformed CL-20 at rates of 0.256 ± 0.011 and 0.043 ± 0.003 nmol min−1 mg of protein−1 under anaerobic and aerobic conditions, respectively. The disappearance of CL-20 was accompanied by the release of nitrite ions. Using liquid chromatography/mass spectrometry in the negative electrospray ionization mode, we detected a metabolite with a deprotonated mass ion [M − H]− at 345 Da, corresponding to an empirical formula of C6H6N10O8, produced as a result of two sequential N denitration steps on the CL- 20 molecule. We also detected two isomeric metabolites with [M − H]− at 381 Da corresponding to an empirical formula of C6H10N10O10. The latter was a hydrated product of the metabolite C6H6N10O8 with addition of two H2O molecules, as confirmed by tests using 18O-labeled water. The product stoichiometry showed that each reacted CL-20 molecule produced about 1.7 nitrite ions, 3.2 molecules of nitrous oxide, 1.5 molecules of formic acid, and 0.6 ammonium ion. Diphenyliodonium-mediated inhibition of salicylate 1-monooxygenase and a comparative study between native, deflavo, and reconstituted enzyme(s) showed that FAD site of the enzyme was involved in the biotransformation of CL-20 catalyzed by salicylate 1-monooxygenase. The data suggested that salicylate 1-monooxygenase catalyzed two oxygen-sensitive single-electron transfer steps necessary to release two nitrite ions from CL-20 and that this was followed by the secondary decomposition of this energetic chemical. PMID:15240281

Initial reaction(s) in biotransformation of CL-20 is catalyzed by salicylate 1-monooxygenase from Pseudomonas sp. strain ATCC 29352.

PubMed

Bhushan, Bharat; Halasz, Annamaria; Spain, Jim C; Hawari, Jalal

2004-07-01

CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) (C(6)H(6)N(12)O(12)), a future-generation high-energy explosive, is biodegradable by Pseudomonas sp. strain FA1 and Agrobacterium sp. strain JS71; however, the nature of the enzyme(s) involved in the process was not understood. In the present study, salicylate 1-monooxygenase, a flavin adenine dinucleotide (FAD)-containing purified enzyme from Pseudomonas sp. strain ATCC 29352, biotransformed CL-20 at rates of 0.256 +/- 0.011 and 0.043 +/- 0.003 nmol min(-1) mg of protein(-1) under anaerobic and aerobic conditions, respectively. The disappearance of CL-20 was accompanied by the release of nitrite ions. Using liquid chromatography/mass spectrometry in the negative electrospray ionization mode, we detected a metabolite with a deprotonated mass ion [M - H](-) at 345 Da, corresponding to an empirical formula of C(6)H(6)N(10)O(8), produced as a result of two sequential N denitration steps on the CL- 20 molecule. We also detected two isomeric metabolites with [M - H](-) at 381 Da corresponding to an empirical formula of C(6)H(10)N(10)O(10). The latter was a hydrated product of the metabolite C(6)H(6)N(10)O(8) with addition of two H(2)O molecules, as confirmed by tests using (18)O-labeled water. The product stoichiometry showed that each reacted CL-20 molecule produced about 1.7 nitrite ions, 3.2 molecules of nitrous oxide, 1.5 molecules of formic acid, and 0.6 ammonium ion. Diphenyliodonium-mediated inhibition of salicylate 1-monooxygenase and a comparative study between native, deflavo, and reconstituted enzyme(s) showed that FAD site of the enzyme was involved in the biotransformation of CL-20 catalyzed by salicylate 1-monooxygenase. The data suggested that salicylate 1-monooxygenase catalyzed two oxygen-sensitive single-electron transfer steps necessary to release two nitrite ions from CL-20 and that this was followed by the secondary decomposition of this energetic chemical.

SERS spectral study of HAuCl4-cysteine nanocatalytic reaction and its application for detection of heparin sodium with label-free VB4r molecular probe

NASA Astrophysics Data System (ADS)

Wang, Xiaoliang; Jiang, Caina; Qin, Yanna; Peng, Yutao; Wen, Guiqing; Liang, Aihui; Jiang, Zhiliang

2017-04-01

In the presence of nanocatalyst, L-cysteine reduce HAuCl4 rapidly to form gold nanoparticles (AuNP), and a quick nanocatalytic preparation procedure was established for Au/AuNP sol with highly active surface enhanced Raman scattering (SERS) effect and good stability. The nanoreaction was also studied by absorption, resonance Rayleigh scattering (RRS), transmission electron microscopy (TEM) and energy spectra. In the selected conditions, the analyte heparin sodium (HS) could react with victoria blue 4 R (VB4r) to form associated complexes which have very weak SERS effect to make the SERS signals decrease. The SERS signals at 1617 cm-1 reduced linearly with HS concentration increasing. Upon addition of FeCl3, it hydrolyzed to form stable Fe(OH)3 sol platform that carried SERS active Au/AuNPs to enhance the sensitivity. Accordingly, we established a SERS quantitative analysis method in the sol substrate of Fe(OH)3-Au/AuNPs, with a linear range of 0.5-75 ng/mL HS and a detection limit of 0.2 ng/mL. HS in real samples was determined, with a relative standard deviation of 2.65-7.63% and a recovery of 99.3-101%.

Integrated Data Collection Analysis (IDCA) Program - NaClO 3/Icing Sugar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandstrom, Mary M.; Brown, Geoffrey W.; Preston, Daniel N.

The Integrated Data Collection Analysis (IDCA) program is conducting a proficiency study for Small- Scale Safety and Thermal (SSST) testing of homemade explosives (HMEs). Described here are the results for impact, friction, electrostatic discharge, and differential scanning calorimetry analysis of a mixture of NaClO 3 and icing sugar—NaClO 3/icing sugar mixture. The mixture was found to: be more sensitive than RDX but less sensitive than PETN in impact testing (180-grit sandpaper); be more sensitive than RDX and about the same sensitivity as PETN in BAM fiction testing; be less sensitive than RDX and PETN except for one participant found themore » mixture more sensitive than PETN in ABL ESD testing; and to have one to three exothermic features with the lowest temperature event occurring at ~ 160°C always observed in thermal testing. Variations in testing parameters also affected the sensitivity.« less

Determination of ampicillin sodium using the cupric oxide nanoparticles-luminol-H2 O2 chemiluminescence reaction.

PubMed

Iranifam, Mortaza; Kharameh, Merhnaz Khabbaz

2014-09-01

A simple and sensitive chemiluminescence (CL) method has been developed for the determination of ampicillin sodium at submicromolar levels. The method is based on the inhibitory effect of ampicillin sodium on the cupric oxide nanoparticles (CuO NPs)-luminol-H2 O2 CL reaction. Experimental parameters affecting CL inhibition including concentrations of CuO NPs, luminol, H2 O2 and NaOH were optimized. Under optimum conditions, the calibration plot was linear in the analyte concentration range 4.0 × 10(-7) -4.0 × 10(-6) mol/L. The limit of detection was 2.6 × 10(-7) mol/L and the relative standard deviation (RSD) for six replicate determinations of 1 × 10(-6) mol/L ampicillin sodium was 4.71%. Also, X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis were employed to characterize the CuO NPs. The utility of the proposed method was demonstrated by determining ampicillin sodium in pharmaceutical preparation. Copyright © 2013 John Wiley & Sons, Ltd.

A method of chemiluminescence coupled with ultrafiltration for investigating the interaction between ibuprofen and human serum albumin.

PubMed

Xiong, Xunyu; Zhang, Qunzheng; Nan, Yefei; Gu, Xuefan

2013-01-01

In acidic media, ibuprofen substantially enhanced the weak chemiluminescence (CL) produced by sodium sulfite and potassium permanganate. The increased signals were linearly correlated with ibuprofen concentrations ranging from 1.2 × 10(-3) to 4.8 μM, with a detection limit of 4.8 × 10(-4) μM. Two ultrafiltration (UF) membranes were used to construct a unit for trapping 0.15 and 0.75 μM human serum albumin (HSA) and coupled online with the CL system. At low HSA concentrations, the numbers of bound molecules per binding site were calculated to be 0.9 for Sudlow site I and 6.2 for Sudlow site II. The association constants on these binding sites were 5.9 × 10(5) and 3.4 × 10(4) M(-1), respectively. Our CL-UF protocol presents a rapid and sensitive method for studies on drug-protein interaction. Copyright © 2012 John Wiley & Sons, Ltd.

Selective and Sensitive Detection of Heavy Metal Ions in 100% Aqueous Solution and Cells with a Fluorescence Chemosensor Based on Peptide Using Aggregation-Induced Emission.

PubMed

Neupane, Lok Nath; Oh, Eun-Taex; Park, Heon Joo; Lee, Keun-Hyeung

2016-03-15

A fluorescent peptidyl chemosensor for the detection of heavy metal ions in aqueous solution as well as in cells was synthesized on the basis of the peptide receptor for the metal ions using an aggregation-induced emission fluorophore. The peptidyl chemosensor (1) bearing tetraphenylethylene fluorophore showed an exclusively selective turn-on response to Hg(2+) among 16 metal ions in aqueous buffered solution containing NaCl. The peptidyl chemosensor complexed Hg(2+) ions and then aggregated in aqueous buffered solution, resulting in the significant enhancement (OFF-On) of emissions at around 470 nm. The fluorescent sensor showed a highly sensitive response to Hg(2+), and about 1.0 equiv of Hg(2+) was enough for the saturation of the emission intensity change. The detection limit (5.3 nM, R(2) = 0.99) of 1 for Hg(2+) ions was lower than the maximum allowable level of Hg(2+) in drinking water by EPA. Moreover, the peptidyl chemosensor penetrated live cells and detected intracellular Hg(2+) ions by the turn-on response.

Potential Interactions of Calcium-Sensitive Reagents with Zinc Ion in Different Cultured Cells

PubMed Central

Fujikawa, Koichi; Fukumori, Ryo; Nakamura, Saki; Kutsukake, Takaya; Takarada, Takeshi; Yoneda, Yukio

2015-01-01

Background Several chemicals have been widely used to evaluate the involvement of free Ca2+ in mechanisms underlying a variety of biological responses for decades. Here, we report high reactivity to zinc of well-known Ca2+-sensitive reagents in diverse cultured cells. Methodology/Principal Findings In rat astrocytic C6 glioma cells loaded with the fluorescent Ca2+ dye Fluo-3, the addition of ZnCl2 gradually increased the fluorescence intensity in a manner sensitive to the Ca2+ chelator EGTA irrespective of added CaCl2. The addition of the Ca2+ ionophore A23187 drastically increased Fluo-3 fluorescence in the absence of ZnCl2, while the addition of the Zn2+ ionophore pyrithione rapidly and additionally increased the fluorescence in the presence of ZnCl2, but not in its absence. In cells loaded with the zinc dye FluoZin-3 along with Fluo-3, a similarly gradual increase was seen in the fluorescence of Fluo-3, but not of FluoZin-3, in the presence of both CaCl2 and ZnCl2. Further addition of pyrithione drastically increased the fluorescence intensity of both dyes, while the addition of the Zn2+ chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine (TPEN) rapidly and drastically decreased FluoZin-3 fluorescence. In cells loaded with FluoZin-3 alone, the addition of ZnCl2 induced a gradual increase in the fluorescence in a fashion independent of added CaCl2 but sensitive to EGTA. Significant inhibition was found in the vitality to reduce 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide in a manner sensitive to TPEN, EDTA and BAPTA in C6 glioma cells exposed to ZnCl2, with pyrithione accelerating the inhibition. Similar inhibition occurred in an EGTA-sensitive fashion after brief exposure to ZnCl2 in pluripotent P19 cells, neuronal Neuro2A cells and microglial BV2 cells, which all expressed mRNA for particular zinc transporters. Conclusions/Significance Taken together, comprehensive analysis is absolutely required for the demonstration of a variety of physiological and pathological responses mediated by Ca2+ in diverse cells enriched of Zn2+. PMID:26010609

Detection of hexamethonium-perchlorate association complexes using NACE-MS.

PubMed

Groom, Carl A; Hawari, Jalal

2007-02-01

Perchlorate (ClO(4) (+)) and other chlorine oxide anions were observed to complex weakly with hexamethonium (1,6-bis-(trimethylammonium)-hexane) in both aqueous and polar nonaqueous solvents. The resultant positively charged complexes were resolved by NACE using 2-propanol/acetone electrolytes prior to mass spectrometric detection using an Agilent(3D)CE system coupled to a Bruker Esquire 3000+ quadrupole IT mass detector. Using electrokinetic injection, the method detection limit for perchlorate in nonaqueous media was 10 microg/L. The isotope patterns due to the presence of (35)Cl and (37)Cl in complex mass spectra allowed for unambiguous identification of perchlorate, chlorate (ClO(3) (+)), chlorite (ClO(2) (+)), and chloride (Cl(+)) in photoreaction samples.

Hollow Au-Ag Nanoparticles Labeled Immunochromatography Strip for Highly Sensitive Detection of Clenbuterol

NASA Astrophysics Data System (ADS)

Wang, Jingyun; Zhang, Lei; Huang, Youju; Dandapat, Anirban; Dai, Liwei; Zhang, Ganggang; Lu, Xuefei; Zhang, Jiawei; Lai, Weihua; Chen, Tao

2017-01-01

The probe materials play a significant role in improving the detection efficiency and sensitivity of lateral-flow immunochromatographic test strip (ICTS). Unlike conventional ICTS assay usually uses single-component, solid gold nanoparticles as labeled probes, in our present study, a bimetallic, hollow Au-Ag nanoparticles (NPs) labeled ICTS was successfully developed for the detection of clenbuterol (CLE). The hollow Au-Ag NPs with different Au/Ag mole ratio and tunable size were synthesized by varying the volume ratio of [HAuCl4]:[Ag NPs] via the galvanic replacement reaction. The surface of hollow Ag-Au NPs was functionalized with 11-mercaptoundecanoic acid (MUA) for further covalently bonded with anti-CLE monoclonal antibody. Overall size of the Au-Ag NPs, size of the holes within individual NPs and also Au/Ag mole ratio have been systematically optimized to amplify both the visual inspection signals and the quantitative data. The sensitivity of optimized hollow Au-Ag NPs probes has been achieved even as low as 2 ppb in a short time (within 15 min), which is superior over the detection performance of conventional test strip using Au NPs. The optimized hollow Au-Ag NPs labeled test strip can be used as an ideal candidate for the rapid screening of CLE in food samples.

Abbott prism: a multichannel heterogeneous chemiluminescence immunoassay analyzer.

PubMed

Khalil, O S; Zurek, T F; Tryba, J; Hanna, C F; Hollar, R; Pepe, C; Genger, K; Brentz, C; Murphy, B; Abunimeh, N

1991-09-01

We describe a multichannel heterogeneous immunoassay analyzer in which a sample is split between disposable reaction trays in a group of linear tracks. The system's pipettor uses noninvasive sensing of the sample volume and disposable pipet tips. Each assay track has (a) a conveyor belt for moving reaction trays to predetermined functional stations, (b) temperature-controlled tunnels, (c) noncontact transfer of the reaction mixture between incubation and detection wells, and (d) single-photon counting to detect a chemiluminescence (CL) signal from the captured immunochemical product. A novel disposable reaction tray, with separate reaction and detection wells and self-contained fluid removal, is used in conjunction with the transfer device on the track to produce a carryover-free system. The linear immunoassay track has nine predetermined positions for performing individual assay steps. Assay step sequence and timing is selected by changing the location of the assay modules between these predetermined positions. The assay methodology, a combination of microparticle capture and direct detection of a CL signal on a porous matrix, offers excellent sensitivity, specificity, and ease of automation. Immunoassay configurations have been tested for hepatitis B surface antigen and for antibodies to hepatitis B core antigen, hepatitis C virus, human immunodeficiency virus I and II, and human T-cell leukemia virus I and II.

Theoretical insight into the binding energy and detonation performance of ε-, γ-, β-CL-20 cocrystals with β-HMX, FOX-7, and DMF in different molar ratios, as well as electrostatic potential.

PubMed

Feng, Rui-Zhi; Zhang, Shu-Hai; Ren, Fu-de; Gou, Rui-Jun; Gao, Li

2016-06-01

Molecular dynamics method was employed to study the binding energies on the selected crystal planes of the ε-, γ-, β-conformation 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (ε-, γ-, β-CL-20) cocrystal explosives with 1,1-diamino-2,2-dinitroethylene (FOX-7), 1,3,5,7-tetranitro- 1,3,5,7-tetrazacyclooctane with β-conformation (β-HMX) and N,N-dimethylformamide (DMF) in different molar ratios. The oxygen balance, density, detonation velocity, detonation pressure, and surface electrostatic potential were analyzed. The results indicate that the binding energies E b (*) and stabilities are in the order of 1:1 > 2:1 > 3:1 > 5:1 > 8:1 (CL-20:FOX-7/β-HMX/DMF). The values of E b (*) and stabilities of the energetic-nonenergetic CL-20/DMF cocrystals are far larger than those of the energetic-energetic CL-20/FOX-7 and CL-20/β-HMX, and those of CL-20/β-HMX are the smallest. For CL-20/FOX-7 and CL-20/β-HMX, the largest E b (*) appears in the cocrystals with the 1:1, 1:2 or 1:3 molar ratio, and the stabilities of the cocrystals with the excess ratio of CL-20 are weaker than those in the cocrystals with the excess ratio of FOX-7 or β-HMX. In CL-20/FOX-7, CL-20 prefers adopting the γ-form, and ε-CL-20 is the preference in CL-20/β-HMX, and ε-CL-20 and β-CL-20 can be found in CL-20/DMF. The CL-20/FOX-7 and CL-20/β-HMX cocrystals with low molar ratios can meet the requirements of low sensitive high energetic materials. Surface electrostatic potential reveals the nature of the sensitivity change upon the cocrystal formation. Graphical Abstract MD method was employed to study the binding energies on the selected crystal planes in the ε-, γ-, β-CL-20 cocrystals with FOX-7, β-HMX and DMF in different molar ratios. Surface electrostatic potential reveals the nature of the sensitivity change in cocrystals.

Amperometric detection of glucose in fruit juices with polypyrrole-based biosensor with an integrated permselective layer for exclusion of interferences.

PubMed

Ayenimo, Joseph G; Adeloju, Samuel B

2017-08-15

A novel polypyrrole (PPy)-based bilayer amperometric glucose biosensor integrated with a permselective layer has been developed for detection of glucose in the presence of interferences. It comprises of a PPy-GOx film grown, in the absence of electrolyte, as an inner layer, and a permselective PPy-Cl film as an outer layer. The PPy-GOx/PPy-Cl bilayer biosensor was effective in rejecting 98% of ascorbic acid and 100% of glycine, glutamic acid and uric acid. With an outer layer thickness of 6.6nm, the bilayer biosensor gave nearly identical glucose response to that of a single layer PPy-GOx biosensor. The biosensor also exhibited good reproducibility (1.9% rsd, n=10), high stability (more than 2months), wide linear range (0.5-24mM), low K m (8.4mM), high I max (77.2μAcm -2 ), low detection limit (26.9μM) and good sensitivity (3.5μAcm -2 mM -1 ). The bilayer biosensor was successfully employed for glucose determination in various fruit juices. Copyright © 2017 Elsevier Ltd. All rights reserved.

A new luminol chemiluminescence sensor for glucose based on pH-dependent graphene oxide.

PubMed

Hao, Minjia; Liu, Na; Ma, Zhanfang

2013-08-07

In this study, graphene oxide (GO) was found to catalyze the luminol-O2 reaction, which yielded a novel chemiluminescence (CL). Remarkably, the CL emission could be tuned by modulating the pH of the GO dispersion. Transmission electron microscopy, CL spectra, electron spin resonance spectra studies were carried out to investigate the CL mechanism. The results indicate that the CL emission was attributed to the intrinsic catalytic effect of GO acting as the radical generation proliferators and electron transfer accelerators. Based on the GO catalyzed luminol-O2 system, we successfully developed a new CL sensor to detect glucose. Under the optimized conditions, glucose could be assayed in the range of 0.05 mM to 5 mM with a detection limit of 0.044 mM. For the detection of clinical serum samples, it is well consistent with the data determined by commercially available method in hospital, indicating that the new CL method provides a possible application for the detection of glucose in clinical diagnostics.

Enhancement of anti-stokes sensitized luminescence in AgCl(I) crystals in the presence of silver nanoparticles

NASA Astrophysics Data System (ADS)

Chung, Nguyen Thi Kim; Egorushina, E. A.; Latyshev, A. N.; Ovchinnikov, O. V.; Smirnov, M. S.; Suvorova, T. I.

2012-01-01

We have observed a significant increase in the intensity with anti-Stokes excitation of recombination luminescence in AgCl(I) microcrystals sensitized by methylene blue molecules in the presence of silver nanoparticles.

Colorimetric and fluorescent chemosensor for highly selective and sensitive relay detection of Cu2 + and H2PO4- in aqueous media

NASA Astrophysics Data System (ADS)

Su, Jun-Xia; Wang, Xiao-Ting; Chang, Jing; Wu, Gui-Yuan; Wang, Hai-Ming; Yao, Hong; Lin, Qi; Zhang, You-Ming; Wei, Tai-Bao

2017-07-01

In this manuscript, a new colorimetric and fluorescent chemosensor (T) was designed and synthesized, it could successively detect Cu2 + and H2PO4- in DMSO/H2O (v/v = 9:1, pH = 7.2) buffer solution with high selectivity and sensitivity. When added Cu2 + ions into the solution of T, it showed a color changes from yellow to colorless, meanwhile, the green fluorescence of sensor T quenched. This recognition behavior was not affected in the presence of other cations, including Hg2 +, Ag+, Ca2 +, Co2 +, Ni2 +, Cd2 +, Pb2 +, Zn2 +, Cr3 +, and Mg2 + ions. More interestingly, the Cu2 + ions contain sensor T solution could recover the color and fluorescence upon the addition of H2PO4- anions in the same medium. And other surveyed anions (including F-, Cl-, Br-, I-, AcO-, HSO4-, ClO4-, CN- and SCN-) had nearly no influence on the recognition behavior. The detection limits of T to Cu2 + and T-Cu2 + to H2PO4- were evaluated to be 1.609 × 10- 8 M and 0.994 × 10- 7 M, respectively. In addition, the sensor T also could be served as a recyclable component and the logic gate output was also defined in sensing materials. The test strips based on sensor T were fabricated, which acted as a convenient and efficient Cu2 + and H2PO4- test kits.

Stimulation of Intestinal Cl- Secretion Through CFTR by Caffeine Intake in Salt-Sensitive Hypertensive Rats.

PubMed

Wei, Xiao; Lu, Zongshi; Yang, Tao; Gao, Peng; Chen, Sijiao; Liu, Daoyan; Zhu, Zhiming

2018-03-16

High salt consumption is a major risk factor for hypertension, and sodium homeostasis is regulated by both intestinal sodium absorption and urinary sodium excretion. Chronic caffeine intake has been reported to attenuate salt-sensitive hypertension by promoting urinary sodium excretion; however, its exact role in intestinal sodium absorption remains unknown. Here, we investigated whether and how chronic caffeine consumption antagonizes salt-sensitive hypertension by inhibiting intestinal sodium absorption. Dahl salt-sensitive rats were fed 8% NaCl chow and 0.1% caffeine in their drinking water for 15 days. The blood pressure and fecal sodium content were measured. The effect of caffeine on the movement of Cl- in enterocyte cells was determined with the Ussing chamber assay. Rats that were treated with caffeine displayed significantly lower mean blood pressure and higher fecal sodium content than the controls. Consistent with these findings, caffeine intake decreased fluid absorption by the intestine in the fluid perfusion experiment. Further, the results from the Ussing chamber assay indicated that caffeine promoted Cl- secretion through enterocyte apical cystic fibrosis transmembrane conductance regulator (CFTR), and thus inhibited sodium absorption. Moreover, depletion of cAMP or inhibition of CFTR completely abolished the effect of caffeine on Cl- secretion. The results indicate that chronic caffeine consumption reduces sodium absorption by promoting CFTR-mediated Cl- secretion in the intestine, which contributes to the anti-hypertensive effect of caffeine in salt-sensitive rats. © 2018 The Author(s). Published by S. Karger AG, Basel.

Selective Isobar Suppression for Accelerator Mass Spectrometry and Radioactive Ion Beam Science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Galindo-Uribarri, Alfredo; Havener, Charles C; Lewis, Thomas L.

2010-01-01

Several applications of AMS will benefit from pushing further the detection limits of AMS isotopes. A new method of selective isobar suppression by photodetachment in a radio-frequency quadrupole ion cooler is being developed at HRIBF with a two-fold purpose: (1) increasing the AMS sensitivity for certain isotopes of interest and (2) purifying radioactive ion beams for nuclear science. The potential of suppressing the 36S contaminants in a 36Cl beam using this method has been explored with stable S- and Cl- ions and a Nd:YLF laser. In the study, the laser beam was directed along the experiment's beam line and throughmore » a RF quadrupole ion cooler. Negative 32S and 35Cl ions produced by a Cs sputter ion source were focused into the ion cooler where they were slowed by collisions with He buffer gas; this increased the interaction time between the negative ion beam and the laser beam. As a result, suppression of S- by a factor of 3000 was obtained with about 2.5 W average laser power in the cooler while no reduction in Cl- current was observed.« less

Utility of NBD-Cl for the spectrophotometric determination of some skeletal muscle relaxant and antihistaminic drugs

NASA Astrophysics Data System (ADS)

Saleh, Hanaa M.; EL-Henawee, Magda M.; Ragab, Gamal H.; El-Hay, Soad S. Abd

2007-08-01

A simple, accurate, precise and sensitive colorimetric method for the determination of some skeletal muscle relaxant drugs, namely orphenadrine citrate ( I), baclofen ( II), antihistaminic drugs as acrivastine ( III) and fexofenadine hydrochloride ( IV) is described. This method is based on the formation of charge transfer complex with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) in non-aqueous medium. The orange color products were measured at 472, 465, 475 and 469 nm for drugs I, II, III and IV, respectively. The optimization of various experimental conditions was described. Beer's Law was obeyed in the range (2.5-17.5), (5-70), (2.5-25) and (10-50) μg/ml for drugs I, II, III and IV, respectively. The molar absorptivity ( ɛ), sandell sensitivity, detection (LOD) and quantitation limits (LOQ) are calculated. The procedure was favorably applied for determination of certain pharmaceutical dosage forms containing the studied drugs. The obtained results were compared with the official and reported methods. There were no significant differences between proposed, reported and the official methods.

Quantitative imaging of disease signatures through radioactive decay signal conversion

PubMed Central

Thorek, Daniel LJ; Ogirala, Anuja; Beattie, Bradley J; Grimm, Jan

2013-01-01

In the era of personalized medicine there is an urgent need for in vivo techniques able to sensitively detect and quantify molecular activities. Sensitive imaging of gamma rays is widely used, but radioactive decay is a physical constant and signal is independent of biological interactions. Here we introduce a framework of novel targeted and activatable probes excited by a nuclear decay-derived signal to identify and measure molecular signatures of disease. This was accomplished utilizing Cerenkov luminescence (CL), the light produced by β-emitting radionuclides such as clinical positron emission tomography (PET) tracers. Disease markers were detected using nanoparticles to produce secondary Cerenkov-induced fluorescence. This approach reduces background signal compared to conventional fluorescence imaging. In addition to information from a PET scan, we demonstrate novel medical utility by quantitatively determining prognostically relevant enzymatic activity. This technique can be applied to monitor other markers and facilitates a shift towards activatable nuclear medicine agents. PMID:24013701

Comparative studies on structures, mechanical properties, sensitivity, stabilities and detonation performance of CL-20/TNT cocrystal and composite explosives by molecular dynamics simulation.

PubMed

Hang, Gui-Yun; Yu, Wen-Li; Wang, Tao; Wang, Jin-Tao; Li, Zhen

2017-09-19

To investigate and compare the differences of structures and properties of CL-20/TNT cocrystal and composite explosives, the CL-20/TNT cocrystal and composite models were established. Molecular dynamics simulations were performed to investigate the structures, mechanical properties, sensitivity, stabilities and detonation performance of cocrystal and composite models with COMPASS force field in NPT ensemble. The lattice parameters, mechanical properties, binding energies, interaction energy of trigger bond, cohesive energy density and detonation parameters were determined and compared. The results show that, compared with pure CL-20, the rigidity and stiffness of cocrystal and composite models decreased, while plastic properties and ductility increased, so mechanical properties can be effectively improved by adding TNT into CL-20 and the cocrystal model has better mechanical properties. The interaction energy of the trigger bond and the cohesive energy density is in the order of CL-20/TNT cocrystal > CL-20/TNT composite > pure CL-20, i.e., cocrystal model is less sensitive than CL-20 and the composite model, and has the best safety parameters. Binding energies show that the cocrystal model has higher intermolecular interaction energy values than the composite model, thus illustrating the better stability of the cocrystal model. Detonation parameters vary as CL-20 > cocrystal > composite, namely, the energy density and power of cocrystal and composite model are weakened; however, the CL-20/TNT cocrystal explosive still has desirable energy density and detonation performance. This results presented in this paper help offer some helpful guidance to better understand the mechanism of CL-20/TNT cocrystal explosives and provide some theoretical assistance for cocrystal explosive design.

Comparison of recombinant cathepsins L1, L2, and L5 as ELISA targets for serodiagnosis of bovine and ovine fascioliasis.

PubMed

Martínez-Sernández, Victoria; Perteguer, María J; Hernández-González, Ana; Mezo, Mercedes; González-Warleta, Marta; Orbegozo-Medina, Ricardo A; Romarís, Fernanda; Paniagua, Esperanza; Gárate, Teresa; Ubeira, Florencio M

2018-05-01

Infections caused by Fasciola hepatica are of great importance in the veterinary field, as they cause important economic losses to livestock producers. Serodiagnostic methods, typically ELISA (with either native or recombinant antigens), are often used for early diagnosis. The use of native antigens, as in the MM3-SERO ELISA (commercialized as BIO K 211, BIO-X Diagnostics), continues to be beneficial in terms of sensitivity and specificity; however, there is interest in developing ELISA tests based on recombinant antigens to avoid the need to culture parasites. Of the antigens secreted by adult flukes, recombinant procathepsin L1 (rFhpCL1) is the most commonly tested in ELISA to date. However, although adult flukes produce three different clades of CLs (FhCL1, FhCL2, and FhCL5), to our knowledge, the diagnostic value of recombinant FhCL2 and FhCL5 has not yet been investigated. In the present study, we developed and tested three indirect ELISAs using rFhpCL1, rFhpCL2, and rFhpCL5 and evaluated their recognition by sera from sheep and cattle naturally infected with F. hepatica. Although the overall antibody response to these three rFhpCLs was similar, some animals displayed preferential recognition for particular rFhpCLs. Moreover, for cattle sera, the highest sensitivity was obtained using rFhpCL2 (97%), being equal for both rFhpCL1 and rFhpCL5 (87.9%), after adjusting cut-offs for maximum specificity. By contrast, for sheep sera, the sensitivity was 100% for the three rFhpCLs. Finally, the presence of truncated and/or partially unfolded molecules in antigen preparations is postulated as a possible source of cross-reactivity.

NaCl responsive taste cells in the mouse fungiform taste buds.

PubMed

Yoshida, R; Horio, N; Murata, Y; Yasumatsu, K; Shigemura, N; Ninomiya, Y

2009-03-17

Previous studies have demonstrated that rodents' chorda tympani (CT) nerve fibers responding to NaCl can be classified according to their sensitivities to the epithelial sodium channel (ENaC) blocker amiloride into two groups: amiloride-sensitive (AS) and -insensitive (AI). The AS fibers were shown to respond specifically to NaCl, whereas AI fibers broadly respond to various electrolytes, including NaCl. These data suggest that salt taste transduction in taste cells may be composed of at least two different systems; AS and AI ones. To further address this issue, we investigated the responses to NaCl, KCl and HCl and the amiloride sensitivity of mouse fungiform papilla taste bud cells which are innervated by the CT nerve. Comparable with the CT data, the results indicated that 56 NaCl-responsive cells tested were classified into two groups; 25 cells ( approximately 44%) narrowly responded to NaCl and their NaCl response were inhibited by amiloride (AS cells), whereas the remaining 31 cells ( approximately 56%) responded not only to NaCl, but to KCl and/or HCl and showed no amiloride inhibition of NaCl responses (AI cells). Amiloride applied to the basolateral side of taste cells had no effect on NaCl responses in the AS and AI cells. Single cell reverse transcription-polymerase chain reaction (RT-PCR) experiments indicated that ENaC subunit mRNA was expressed in a subset of AS cells. These findings suggest that the mouse fungiform taste bud is composed of AS and AI cells that can transmit taste information differently to their corresponding types of CT fibers, and apical ENaCs may be involved in the NaCl responses of AS cells.

Surface enhanced Raman scattering (SERS) spectra of trinitrotoluene in silver colloids prepared by microwave heating method.

PubMed

Zhang, Chunling; Wang, Kaijun; Han, Dejun; Pang, Qing

2014-03-25

Surface enhanced Raman spectroscopy (SERS) has been demonstrated for the detection of trace levels of explosives due to its high sensitivity, speed of detection and fingerprint feature. 2,4,6-Trinitrotoluene (TNT), a leading example of nitroaromatic explosives, is causing wide concern. In this study, SERS spectra of TNT solution in silver colloids have been successfully measured and a comparison was drawn with the normal Raman spectra of bulk TNT. The silver colloids were prepared by the microwave heating method and characterized by UV-Vis spectra and the scanning electron microscopy (SEM). NaCl and pH value have a great impact on SERS intensity of TNT, the corresponding experimental research results and theoretical interpretations were further illustrated to a certain extent. Moreover, the detection limit of TNT in aqueous solution was achieved as low as 10(-10) mol L(-1) and some preliminary experiments of detecting TNT vapor (about 10 μg/L) using SERS have been carried out. Our results demonstrated the potential of SERS for probing TNT with high sensitivity, and suggest SERS as a powerful method for detection of TNT and similar species at trace levels. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of sensitive and selective food sensors using new Re(I)-Pt(II) bimetallic complexes to detect volatile biogenic sulfides formed by meat spoilage.

PubMed

Chow, Cheuk-Fai; Ho, Pui-Yu; Sun, Dong; Lu, Yu-Jing; Wong, Wing-Leung; Tang, Qian; Gong, Cheng-Bin

2017-02-01

Detection of volatile biogenic sulfides (VBS) plays a crucial role in food safety because the amounts of these compounds can reflect the freshness of meat. A new indicator-displacement assay with Re(I)-Pt(II) complexes, [Re(Lig)(CO)3(bridge)]-[Pt(DMSO)(Cl)2] (1: Lig=5-phenyl-1,10-phenanthroline and bridge=NCS(-); 2: Lig=5-phenyl-1,10-phenanthroline and bridge=CN(-); 3: Lig=2,2'-biquinoline and bridge=NCS(-)), was demonstrated to be a very effective sensing method to VBS. The results indicated that the control of Re(I)-bridge-Pt(II) and Re(I)-ligand combination are able to regulate their sensing selectivity and sensitivity. This system was successfully applied to detect CH3SCH3 in real rotten pork with a linear luminometric response up to 20.0mgkg(-1) (R=0.997) with the detection limit as 0.05 mgkg(-1). Complex 1 also gave comparable results on the detection of VBS with respect to those determined by GCMS with recovery range from 76% to 102% (RSD%=13.8). Copyright © 2016 Elsevier Ltd. All rights reserved.

CD8+ T cells stimulate Na-Cl co-transporter NCC in distal convoluted tubules leading to salt-sensitive hypertension.

PubMed

Liu, Yunmeng; Rafferty, Tonya M; Rhee, Sung W; Webber, Jessica S; Song, Li; Ko, Benjamin; Hoover, Robert S; He, Beixiang; Mu, Shengyu

2017-01-09

Recent studies suggest a role for T lymphocytes in hypertension. However, whether T cells contribute to renal sodium retention and salt-sensitive hypertension is unknown. Here we demonstrate that T cells infiltrate into the kidney of salt-sensitive hypertensive animals. In particular, CD8 + T cells directly contact the distal convoluted tubule (DCT) in the kidneys of DOCA-salt mice and CD8 + T cell-injected mice, leading to up-regulation of the Na-Cl co-transporter NCC, p-NCC and the development of salt-sensitive hypertension. Co-culture with CD8 + T cells upregulates NCC in mouse DCT cells via ROS-induced activation of Src kinase, up-regulation of the K + channel Kir4.1, and stimulation of the Cl - channel ClC-K. The last event increases chloride efflux, leading to compensatory chloride influx via NCC activation at the cost of increasing sodium retention. Collectively, these findings provide a mechanism for adaptive immunity involvement in the kidney defect in sodium handling and the pathogenesis of salt-sensitive hypertension.

Effect of systemic monosodium glutamate (MSG) on headache and pericranial muscle sensitivity.

PubMed

Baad-Hansen, L; Cairns, Be; Ernberg, M; Svensson, P

2010-01-01

We conducted a double-blinded, placebo-controlled, crossover study to investigate the occurrence of adverse effects such as headache as well as pain and mechanical sensitivity in pericranial muscles after oral administration of monosodium glutamate (MSG). In three sessions, 14 healthy men drank sugar-free soda that contained either MSG (75 or 150 mg/kg) or NaCl (24 mg/kg, placebo). Plasma glutamate level, pain, pressure pain thresholds and tolerance levels, blood pressure (BP), heart rate and reported adverse effects were assessed for 2 h. No muscle pain or robust changes in mechanical sensitivity were detected, but there was a significant increase in reports of headache and subjectively reported pericranial muscle tenderness after MSG. Systolic BP was elevated in the high MSG session compared with low MSG and placebo. These findings add new information to the concept of MSG headache and craniofacial pain sensitivity.

A reliable combination method to identification and typing of epidemic and endemic clones among clinical isolates of Acinetobacter baumannii.

PubMed

Piran, Arezoo; Shahcheraghi, Fereshteh; Solgi, Hamid; Rohani, Mahdi; Badmasti, Farzad

2017-10-01

The multi-drug resistant (MDR) Acinetobacter baumannii as an important nosocomial pathogen has emerged a global health concern in recent years. In this study, we applied three easier, faster, and cost-effective methods including PCR-based open reading frames (ORFs) typing, sequence typing of bla OXA-51-like and RAPD-PCR method to rapid typing of A. baumannii strains. Taken together in the present study the results of ORFs typing, PCR-sequencing of bla OXA-51-like genes and MLST sequence typing revealed there was a high prevalence (62%, 35/57) of ST2 as international and successful clone which detected among clinical isolates of multi-drug resistant A. baumannii with ORF pattern B and bla OXA-66 gene. Only 7% (4/57) of MDR isolates belonged to ST1 with ORF pattern A and bla OXA-69 gene. Interestingly, we detected singleton ST513 (32%, 18/57) that encoded bla OXA-90 and showed the ORF pattern H as previously isolated in Middle East. Moreover, our data showed RAPD-PCR method can detect divergent strains of the STs. The Cl-1, Cl-2, Cl-3, Cl-4, Cl-10, Cl-11, Cl-12, Cl-13 and Cl-14 belonged to ST2. While the Cl-6, Cl-7, Cl-8 and Cl-9 belonged to ST513. Only Cl-5 belonged to ST1. It seems that the combination of these methods have more discriminatory than any method separately and could be effectively applied to rapid detection of the clonal complex (CC) of A. baumannii strains without performing of MLST or PFGE. Copyright © 2017 Elsevier B.V. All rights reserved.

Strain difference in amiloride-sensitivity of salt-induced responses in mouse non-dissociated taste cells.

PubMed

Miyamoto, T; Fujiyama, R; Okada, Y; Sato, T

1999-12-17

The chorda tympani nerve responses to NaCl in a mouse strain, C57BL/6 are known to be much more sensitive than those in BALB/c. We compared the NaCl-induced responses obtained from taste cells of the fungiform papillae in these two strains of mice. Amiloride inhibited, in the same degree, the responses induced by a bath-application of normal extracellular solution (NES) containing 140 mM NaCl in either taste cells of C57BL/6 and BALB/c mice. In contrast, amiloride inhibited 62% of responses induced by an apically applied 0.5 M NaCl in the C57BL/6 strain, but only 33% of responses in the BALB/c strain. These results suggest that the difference in amiloride-sensitivity between taste cells in both strains mainly derives from the difference in density of functional amiloride sensitive Na+ channels at the apical receptive membrane but not at the basolateral membrane.

Synthesis and characterization of substituted Schiff-base ligands and their d(10) metal complexes: structure-induced luminescence tuning behaviors and applications in co-sensitized solar cells.

PubMed

Dong, Yu-Wei; Fan, Rui-Qing; Wang, Ping; Wei, Li-Guo; Wang, Xin-Ming; Zhang, Hui-Jie; Gao, Song; Yang, Yu-Lin; Wang, Yu-Lei

2015-03-28

Nine IIB group complexes, [ZnL1Cl2] (Zn1), [CdL1Cl2]2 (Cd1), [HgL1Cl2] (Hg1), [ZnL2Cl2] (Zn2), [CdL2Cl2] (Cd2), [HgL2Cl2] (Hg2), [ZnL3Cl2] (Zn3), [CdL3Cl2] (Cd3) and [HgL3Cl2] (Hg3), have been synthesized from the corresponding ortho-(6-methoxy-pyridyl)(CH[double bond, length as m-dash]NAr) (where Ar = 2,6-iPr2C6H3, L1; 4-MeC6H4, L2; 2-OMeC6H4, L3) Schiff base and structurally characterized by elemental analysis, FT-IR, (1)H NMR and X-ray single-crystal analysis. Crystallographic studies reveal that the center metal of the complexes adopts a distorted tetrahedron geometry (except for Cd1 and Cd3, which display square pyramidal geometry) and C-HCl hydrogen bonds and ππ stacking interactions contribute to three-dimensional supramolecular structures. The series of complexes exhibit tunable luminescence from blue, through green, to light yellow by varying the temperature (298 K and 77 K), both in solution and in the solid state. Moreover, the quantum yields range from 0.027 to 0.422, and decrease according to the order of the periodic table (Zn > Cd > Hg). These results indicate that the center atom of the complexes leads to the geometry differences and hence to the tunable luminescence properties. Because Zn1-Zn3 exhibited higher molar extinction coefficients and a distinct absorption region, they were employed as co-sensitizers in ruthenium dye N719-sensitized photoanodes to deliver light-electricity efficiency enhancement, being assembled with counter-electrodes and electrolyte to prepare ZnX/N719 (where ZnX = Zn1, Zn2, and Zn3) co-sensitized dye sensitized solar cell (DSSC) devices. The prepared co-absorbent could overcome the deficiency of N719 absorption in the low-wavelength region of the visible spectrum, and offset competitive visible-light absorption of I3(-). Application of these prepared complexes in N719-sensitized solar cells enhanced their performance by 10-36%, which indicated a potential application of these types of complexes in DSSCs.

High Tumor Penetration of Paclitaxel Loaded pH Sensitive Cleavable Liposomes by Depletion of Tumor Collagen I in Breast Cancer.

PubMed

Zhang, Li; Wang, Yang; Yang, Yuting; Liu, Yayuan; Ruan, Shaobo; Zhang, Qianyu; Tai, Xiaowei; Chen, Jiantao; Xia, Tai; Qiu, Yue; Gao, Huile; He, Qin

2015-05-13

The network of collagen I in tumors could prevent the penetration of drugs loaded in nanoparticles, and this would lead to impaired antitumor efficacy. In this study, free losartan (an angiotensin inhibitor) was injected before treatment to reduce the level of collagen I, which could facilitate the penetration of nanoparticles. Then the pH-sensitive cleavable liposomes (Cl-Lip) were injected subsequently to exert the antitumor effect. The Cl-Lip was constituted by PEG(5K)-Hydrazone-PE and DSPE-PEG(2K)-R8. When the Cl-Lip reached to the tumor site by the enhanced permeability and retention (EPR) effect, PEG(5K)-Hydrazone-PE was hydrolyzed from the Cl-Lip under the low extra-cellular pH conditions of tumors, then the R8 peptide was exposed, and finally liposomes could be internalized into tumor cells by the mediation of R8 peptide. In vitro experiments showed both the cellular uptake of Cl-Lip by 4T1 cells and cytotoxicity of paclitaxel loaded Cl-Lip (PTX-Cl-Lip) were pH sensitive. In vivo experiments showed the Cl-Lip had a good tumor targeting ability. After depletion of collagen I, Cl-Lip could penetrate into the deep place of tumors, the tumor accumulation of Cl-Lip was further increased by 22.0%, and the oxygen distributed in tumor tissues was also enhanced. The antitumor study indicated free losartan in combination with PTX-Cl-Lip (59.8%) was more effective than injection with PTX-Cl-Lip only (37.8%) in 4T1 tumor bearing mice. All results suggested that depletion of collagen I by losartan dramatically increased the penetration of PTX-Cl-Lip and combination of free losartan and PTX-CL-Lip could lead to better antitumor efficacy of chemical drugs. Thus, the combination strategy might be a promising tactic for better treatment of solid tumors with a high level of collagen I.

Long-lived crowded-litter mice exhibit lasting effects on insulin sensitivity and energy homeostasis.

PubMed

Sadagurski, Marianna; Landeryou, Taylor; Blandino-Rosano, Manuel; Cady, Gillian; Elghazi, Lynda; Meister, Daniel; See, Lauren; Bartke, Andrzej; Bernal-Mizrachi, Ernesto; Miller, Richard A

2014-06-01

The action of nutrients on early postnatal growth can influence mammalian aging and longevity. Recent work has demonstrated that limiting nutrient availability in the first 3 wk of life [by increasing the number of pups in the crowded-litter (CL) model] leads to extension of mean and maximal lifespan in genetically normal mice. In this study, we aimed to characterize the impact of early-life nutrient intervention on glucose metabolism and energy homeostasis in CL mice. In our study, we used mice from litters supplemented to 12 or 15 pups and compared those to control litters limited to eight pups. At weaning and then throughout adult life, CL mice are significantly leaner and consume more oxygen relative to control mice. At 6 mo of age, CL mice had low fasting leptin concentrations, and low-dose leptin injections reduced body weight and food intake more in CL female mice than in controls. At 22 mo, CL female mice also have smaller adipocytes compared with controls. Glucose and insulin tolerance tests show an increase in insulin sensitivity in 6 mo old CL male mice, and females become more insulin sensitive later in life. Furthermore, β-cell mass was significantly reduced in the CL male mice and was associated with reduction in β-cell proliferation rate in these mice. Together, these data show that early-life nutrient intervention has a significant lifelong effect on metabolic characteristics that may contribute to the increased lifespan of CL mice.

Revealing interaction between sulfobutylether-β-cyclodextrin and reserpine by chemiluminescence and site-directed molecular docking.

PubMed

Xiong, Xunyu; Wu, Min; Zhao, Xinfeng; Song, Zhenghua

2014-09-01

The host-guest interaction between sulfobutylether-β-cyclodextrin (SBE-β-CD) and reserpine (RSP) is described using flow injection-chemiluminescence (FI-CL) and site-directed molecular docking methods. It was found that RSP could inhibit the CL intensity produced by a luminol/SBE-β-CD system. The decrease in CL intensity was logarithmic over an RSP concentration range of 0.03 to 700.0 nM, giving a regression equation of ∆I = 107.1lgCRES  + 186.1 with a detection limit of 10 pM (3σ). The CL assay was successfully applied in the determination of RSP in injection, saliva and urine samples with recoveries in the range 93.5-106.1%. Using the proposed CL model, the binding constant (KCD-R ) and the stoichiometric ratio of SBE-β-CD/RSP were calculated to be 7.4 × 10(6)  M(-1) and 1 : 1, respectively. Using molecular docking, it was confirmed that luminol binds to the small cavity of SBE-β-CD with a nonpolar interaction, while RSP targeted the larger cavity of SBE-β-CD and formed a 1 : 1 complex with hydrogen bonds. The proposed new CL method has the potential to become a powerful tool for revealing the host-guest interaction between CDs and drugs, as well as monitoring drugs with high sensitivity. Copyright © 2013 John Wiley & Sons, Ltd.

Cutaneous Leishmaniasis in Khyber Pakhtunkhwa Province of Pakistan: Clinical Diversity and Species-Level Diagnosis

PubMed Central

Khan, Nazma Habib; Bari, Arfan ul; Hashim, Rizwan; Khan, Inamullah; Muneer, Akhtar; Shah, Akram; Wahid, Sobia; Yardley, Vanessa; O'Neil, Brighid; Sutherland, Colin J.

2016-01-01

This study primarily aimed to identify the causative species of cutaneous leishmaniasis (CL) in the Khyber Pakhtunkhwa Province of Pakistan and to distinguish any species-specific variation in clinical manifestation of CL. Diagnostic performance of different techniques for identifying CL was assessed. Isolates of Leishmania spp. were detected by in vitro culture, polymerase chain reaction (PCR) on DNA extracted from dried filter papers and microscopic examination of direct lesion smears from patients visiting three major primary care hospitals in Peshawar. A total of 125 CL patients were evaluated. Many acquired the disease from Peshawar and the neighboring tribal area of Khyber Agency. Military personnel acquired CL while deployed in north and south Waziristan. Leishmania tropica was identified as the predominant infecting organism in this study (89.2%) followed by Leishmania major (6.8%) and, unexpectedly, Leishmania infantum (4.1%). These were the first reported cases of CL caused by L. infantum in Pakistan. PCR diagnosis targeting kinetoplast DNA was the most sensitive diagnostic method, identifying 86.5% of all samples found positive by any other method. Other methods were as follows: ribosomal DNA PCR (78.4%), internal transcribed spacer 2 region PCR (70.3%), culture (67.1%), and microscopy (60.5%). Clinical examination reported 14 atypical forms of CL. Atypical lesions were not significantly associated with the infecting Leishmania species, nor with “dry” or “wet” appearance of lesions. Findings from this study provide a platform for species typing of CL patients in Pakistan, utilizing a combination of in vitro culture and molecular diagnostics. Moreover, the clinical diversity described herein can benefit clinicians in devising differential diagnosis of the disease. PMID:27601518

Xanthine derivatives without PDE effect stimulate voltage-activated chloride conductance of toad skin.

PubMed

Nagel, Wolfram; Katz, Uri

2003-02-01

The effect of xanthine derivatives on the voltage-activated Cl(-) conductance (G(Cl)) of amphibian skin was analyzed. 3-Isobutyl-1-methylxanthine (IBMX) and the recently synthesized xanthine derivatives 3,7-dimethyl-1-propyl xanthine (X-32) and 3,7-dimethyl-1-isobutyl xanthine (X-33), which lack inhibitory effects on phosphodiesterases in CHO and Calu-3 cells, increased voltage-activated G(Cl) without effect on baseline conductance at inactivating voltage. Half-maximal stimulation of G(Cl) occurred at 108 +/- 9 microM for X-32 and X-33 after apical or basolateral application. The stimulation of G(Cl), which occurs only in the presence of Cl(-) in the mucosal solution, is caused by a shift of the voltage sensitivity to lower clamp potentials and an increase of the maximally activated level. Furosemide reversed both the shift of sensitivity and the increase in magnitude. These patterns are fundamentally different from those seen after application of membrane-permeant, nonmetabolized analogs of cAMP, and they indicate that the xanthines stimulate G(Cl) directly. This notion is strengthened by the lack of influence on intracellular cAMP content, which is consistent with the observations in CHO and Calu-3 cells. We propose that the xanthine derivatives increase the voltage sensitivity of a regulative component in the conductive Cl(-) pathway across amphibian skin.

[A study on europium sensitized chemiluminescence of pipemidic acid].

PubMed

Li, Xia; Qiang, Hong; Wang, Xiao-li; Chen, Shi-lü; Zhao, Hui-chun

2004-12-01

A flow injection chemiluminescence method for the determination of Pipemidic acid (PPA) was developed. It is based on luminescence produced with KMnO4-Na2S2O4 CL system sensitized by Eu3+-PPA. The familar excipients such as starch and dextrine do not cause interference. The several kinds of affect on chemiluminescence were studied. The linear range and detection limit for PPA are 7.00 x 10(-9)-9.00 x 10(-7) mol x L(-1) and 4.09 x 10(-9) mol x L(-1), respectively. This method have successfully been applied to the determination of PPA in tablet and urine. And the mechanism of chemiluminescence is proposed.

Evaluation of PCR for cutaneous leishmaniasis diagnosis and species identification using filter paper samples in Panama, Central America.

PubMed

Miranda, A; Saldaña, A; González, K; Paz, H; Santamaría, G; Samudio, F; Calzada, J E

2012-09-01

Cutaneous leishmaniasis (CL) is a major vectorborne disease in Panama. In this study, the diagnostic performance and usefulness of two DNA extraction procedures from skin scraping samples collected on FTA filter paper for subsequent PCR diagnosis of CL was evaluated. A positive CL laboratory diagnosis was based on a positive parasitological test (Giemsa-stained smears or in vitro culture) and/or positive PCR test performed from skin scrapings collected in TE buffer (PCR-TE). Of 100 patients with skin lesions suggestive of CL, 82 (82%) were confirmed as CL positive. The sensitivity was calculated for each of the PCR approaches from samples collected on filter paper. The highest sensitivity was achieved by PCR-FTA processed by Chelex 100 (PCR-Chelex) (0.94). PCR-FTA extracted using the FTA purification reagent presented a lower sensitivity (0.60). Good concordance between routine PCR-TE and PCR-Chelex was observed (percent agreement=0.88, κ index=0.65). In conclusion, use of FTA filter paper for skin scraping collection combined with PCR is a reliable and convenient method for CL diagnosis in Panama, with comparable performance to the routine PCR method and with improved sensitivity compared with those of conventional parasitological methods. Copyright © 2012 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.

Point Source Polarimetry with the Gemini Planet Imager: Sensitivity Characterization with T5.5 Dwarf Companion HD 19467 B

NASA Technical Reports Server (NTRS)

Jensen-Clem, Rebecca; Millar-Blanchaer, Max; Mawet, Dimitri; Graham, James R.; Wallace, J. Kent; Macintosh, Bruce; Hinkley, Sasha; Wiktorowicz, Sloane J.; Perrin, Marshall D.; Marley, Mark S.;

Point source polarimetry with the Gemini planet imager: Sensitivity characterization with T5.5 dwarf companion HD 19467 B

DOE PAGES

Jensen-Clem, Rebecca; Millar-Blanchaer, Max; Mawet, Dimitri; ...

2016-03-29

Detecting polarized light from self-luminous exoplanets has the potential to provide key information about rotation, surface gravity, cloud grain size, and cloud coverage. While field brown dwarfs with detected polarized emission are common, no exoplanet or substellar companion has yet been detected in polarized light. With the advent of high contrast imaging spectro-polarimeters such as GPI and SPHERE, such a detection may now be possible with careful treatment of instrumental polarization. In this paper, we present 28 minutes of H-band GPI polarimetric observations of the benchmark T5.5 companion HD 19467 B. We detect no polarization signal from the target, and place an upper limit on the degree of linear polarization ofmore » $${p}_{\\mathrm{CL}99.73\\%}\\leqslant 2.4\\%$$. In conclusion, we discuss our results in the context of T dwarf cloud models and photometric variability.« less

Development of an Ultrasonication-Assisted Extraction Based HPLC With a Fluorescence Method for Sensitive Determination of Aflatoxins in Highly Acidic Hibiscus sabdariffa

PubMed Central

Liu, Xiaofei; Ying, Guangyao; Sun, Chaonan; Yang, Meihua; Zhang, Lei; Zhang, Shanshan; Xing, Xiaoyan; Li, Qian; Kong, Weijun

2018-01-01

The high acidity and complex components of Hibiscus sabdariffa have provided major challenges for sensitive determination of trace aflatoxins. In this study, sample pretreatment of H. sabdariffa was systematically developed for sensitive high performance liquid chromatography-fluorescence detection (HPLC-FLD) after ultrasonication-assisted extraction, immunoaffinity column (IAC) clean-up and on-line post-column photochemical derivatization (PCD). Aflatoxins B1, B2, G1, G2 were extracted from samples by using methanol/water (70:30, v/v) with the addition of NaCl. The solutions were diluted 1:8 with 0.1 M phosphate buffer (pH 8.0) to negate the issues of high acidity and matrix interferences. The established method was validated with satisfactory linearity (R > 0.999), sensitivity (limits of detection (LODs) and limits of quantitation (LOQs) of 0.15–0.65 and 0.53–2.18 μg/kg, respectively), precision (RSD <11%), stability (RSD of 0.2–3.6%), and accuracy (recovery rates of 86.0–102.3%), which all met the stipulated analytical requirements. Analysis of 28 H. sabdariffa samples indicated that one sample incubated with Aspergillus flavus was positive with aflatoxin B1 (AFB1) at 3.11 μg/kg. The strategy developed in this study also has the potential to reliably extract and sensitively detect more mycotoxins in other complex acidic matrices, such as traditional Chinese medicines, foodstuffs, etc. PMID:29681848

Development of an Ultrasonication-Assisted Extraction Based HPLC With a Fluorescence Method for Sensitive Determination of Aflatoxins in Highly Acidic Hibiscus sabdariffa.

PubMed

Liu, Xiaofei; Ying, Guangyao; Sun, Chaonan; Yang, Meihua; Zhang, Lei; Zhang, Shanshan; Xing, Xiaoyan; Li, Qian; Kong, Weijun

2018-01-01

The high acidity and complex components of Hibiscus sabdariffa have provided major challenges for sensitive determination of trace aflatoxins. In this study, sample pretreatment of H. sabdariffa was systematically developed for sensitive high performance liquid chromatography-fluorescence detection (HPLC-FLD) after ultrasonication-assisted extraction, immunoaffinity column (IAC) clean-up and on-line post-column photochemical derivatization (PCD). Aflatoxins B 1 , B 2 , G 1 , G 2 were extracted from samples by using methanol/water (70:30, v/v ) with the addition of NaCl. The solutions were diluted 1:8 with 0.1 M phosphate buffer (pH 8.0) to negate the issues of high acidity and matrix interferences. The established method was validated with satisfactory linearity ( R > 0.999), sensitivity (limits of detection (LODs) and limits of quantitation (LOQs) of 0.15-0.65 and 0.53-2.18 μg/kg, respectively), precision (RSD <11%), stability (RSD of 0.2-3.6%), and accuracy (recovery rates of 86.0-102.3%), which all met the stipulated analytical requirements. Analysis of 28 H. sabdariffa samples indicated that one sample incubated with Aspergillus flavus was positive with aflatoxin B 1 (AFB 1 ) at 3.11 μg/kg. The strategy developed in this study also has the potential to reliably extract and sensitively detect more mycotoxins in other complex acidic matrices, such as traditional Chinese medicines, foodstuffs, etc.

Luminol-Based Chemiluminescent Signals: Clinical and Non-clinical Application and Future Uses

PubMed Central

Khan, Parvez; Idrees, Danish; Moxley, Michael A.; Corbett, John A.; Ahmad, Faizan; von Figura, Guido; Sly, William S.; Waheed, Abdul

2015-01-01

Chemiluminescence (CL) is an important method for quantification and analysis of various macromolecules. A wide range of CL agents such as luminol, hydrogen peroxide, fluorescein, dioxetanes and derivatives of oxalate, and acridinium dyes are used according to their biological specificity and utility. This review describes the application of luminol chemiluminescence (LCL) in forensic, biomedical, and clinical sciences. LCL is a very useful detection method due to its selectivity, simplicity, low cost, and high sensitivity. LCL has a dynamic range of applications, including quantification and detection of macro and micromolecules such as proteins, carbohydrates, DNA, and RNA. Luminol-based methods are used in environmental monitoring as biosensors, in the pharmaceutical industry for cellular localization and as biological tracers, and in reporter gene-based assays and several other immunoassays. Here, we also provide information about different compounds that may enhance or inhibit the LCL along with the effect of pH and concentration on LCL. This review covers most of the significant information related to the applications of luminol in different fields. PMID:24752935

Remote detection of stress corrosion cracking: Surface composition and crack detection

NASA Astrophysics Data System (ADS)

Lissenden, Cliff J.; Jovanovic, Igor; Motta, Arthur T.; Xiao, Xuan; Le Berre, Samuel; Fobar, David; Cho, Hwanjeong; Choi, Sungho

2018-04-01

Chloride induced stress corrosion cracking (SCC) of austenitic stainless steel is a potential issue in long term dry storage of spent nuclear fuel canisters. In order for SCC to occur there must be a corrosive environment, a susceptible material, and a driving force. Because it is likely that the material in the heat affected zone (HAZ) of welded stainless steel structures has been sensitized as a result of chromium depletion at the grain boundaries and a thermal residual stress driving force is likely present if solution annealing is not performed, two issues are critical. Is the environment corrosive, i.e., are chlorides present in solution on the surface? And then, are there cracks that could propagate? Remote detection of chlorides on the surface can be accomplished by laser induced breakdown spectroscopy (LIBS), while cracks can be detected by shear horizontal guided waves generated by electromagnetic acoustic transducers (EMATs). Both are noncontact methods that are amenable to robotic delivery systems and harsh environments. The sensitivity to chlorine on stainless steel of a LIBS system that employs optical fiber for pulse delivery is demonstrated. Likewise, the ability of the EMAT system to detect cracks of a prescribed size and orientation is shown. These results show the potential for remote detection of Cl and cracks in dry storage spent fuel canisters.

Functional expression of the Na-K-2Cl cotransporter NKCC2 in mammalian cells fails to confirm the dominant-negative effect of the AF splice variant.

PubMed

Hannemann, Anke; Christie, Jenny K; Flatman, Peter W

2009-12-18

The renal bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) is the major salt transport pathway in the apical membrane of the mammalian thick ascending limb. It is differentially spliced and the three major variants (A, B, and F) differ in their localization and transport characteristics. Most knowledge about its regulation comes from experiments in Xenopus oocytes as NKCC2 proved difficult to functionally express in a mammalian system. Here we report the cloning and functional expression of untagged and unmodified versions of the major splice variants from ferret kidney (fNKCC2A, -B, and -F) in human embryonic kidney (HEK) 293 cells. Many NKCC2 antibodies used in this study detected high molecular weight forms of the transfected proteins, probably NKCC2 dimers, but not the monomers. Interestingly, monomers were strongly detected by phosphospecific antibodies directed against phosphopeptides in the regulatory N terminus. Bumetanide-sensitive (86)Rb uptake was significantly higher in transfected HEK-293 cells and could be stimulated by incubating cells in a medium containing a low chloride concentration prior the uptake measurements. fNKCC2 was less sensitive to the reduction in chloride concentration than NKCC1. Using HEK-293 cells stably expressing fNKCC2A we also show that co-expression of variant NKCC2AF does not have the dominant-negative effect on NKCC2A activity that was seen in Xenopus oocytes, nor is it trafficked to the cell surface. In addition, fNKCC2AF is neither complex glycosylated nor phosphorylated in its N terminus regulatory region like other variants.

Cardiolipin-Specific Peroxidase Reactions of Cytochrome c in Mitochondria During Irradiation-Induced Apoptosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belikova, Natalia A.; Jiang Jianfei; Tyurina, Yulia Y.

2007-09-01

Purpose: To determine whether cytochrome c (cyt c) content and associated cardiolipin oxidation can be determinants of cell sensitivity to irradiation-induced apoptosis. Methods and Materials: The small interfering RNA (siRNA) approach was used to engineer HeLa cells with lowered contents of cyt c (14%, HeLa 1.2 cells). Cells were treated by {gamma}-irradiation (in doses of 5-40 Gy). Lipid oxidation was characterized by electrospray ionization mass spectrometry analysis and fluorescence high-performance liquid chromatography-based Amplex Red assay. Release of a proapoptotic factor (cyt c, Smac/DIABLO) was detected by Western blotting. Apoptosis was revealed by caspase-3/7 activation and phosphatidylserine externalization. Results: Irradiation causedmore » selective accumulation of hydroperoxides in cardiolipin (CL) but not in other phospholipids. HeLa 1.2 cells responded by a lower irradiation-induced accumulation of CL oxidation products than parental HeLa cells. Proportionally decreased release of a proapoptotic factor, Smac/DIABLO, was detected in cyt c-deficient cells after irradiation. Caspase-3/7 activation and phosphatidylserine externalization were proportional to the cyt c content in cells. Conclusions: Cytochrome c is an important catalyst of CL peroxidation, critical to the execution of the apoptotic program. This new role of cyt c in irradiation-induced apoptosis is essential for the development of new radioprotectors and radiosensitizers.« less

Improved method for efficient imaging of intracellular Cl− with Cl-Sensor using conventional fluorescence setup

PubMed Central

Friedel, Perrine; Bregestovski, Piotr; Medina, Igor

2013-01-01

Chloride (Cl−) homeostasis is known to be fundamental for central nervous system functioning. Alterations in intracellular Cl− concentration ([Cl−]i) and changes in the efficacy of Cl− extrusion are involved in numerous neurological disorders. Therefore, there is a strong need for studies of the dynamics of [Cl−]i in different cell types under physiological conditions and during pathology. Several previous works reported having successfully achieved recording of [Cl−]i using genetically encoded Cl-Sensor that is composed of the cyan fluorescent protein (CFP) and Cl−-sensitive mutant of the yellow fluorescent protein (YFPCl). However, all reported works were performed using specially designed setups with ultra-sensitive CCD cameras. Our multiple attempts to monitor Cl−-dependent fluorescence of Cl-Sensor using conventional epifluorescence microscopes did not yield successful results. In the present work, we have analysed the reason of our failures and found that they were caused by a strong inactivation of the YFPCl component of Cl-Sensor during excitation of the CFP with 430 nm light. Based on the obtained results, we reduced 20-fold the intensity of the 430 nm excitation and modified the recording protocol that allows now stable long-lasting ratiometric measurements of Cl-Sensor fluorescence in different cell types including cultured hippocampal neurons and their tiny dendrites and spines. Simultaneous imaging and patch clamp recording revealed that in mature neurons, the novel protocol allows detection of as little as 2 mM changes of [Cl−]i from the resting level of 5–10 mM. We demonstrate also a usefulness of the developed [Cl−]i measurement procedure for large scale screening of the activity of exogenously expressed potassium-chloride co-transporter KCC2, a major neuronal Cl− extruder that is implicated in numerous neurological disorders and is a target for novel therapeutical treatments. PMID:23596389

Physical and chemical microstructural damage in pressed CL-20 explosives

NASA Astrophysics Data System (ADS)

Demol, Gauthier; Sandusky, Harold W.

2000-04-01

The ultimate utility of CL-20 as an ingredient in explosive and propellant formulations will depend upon the ability to understand the factors that are responsible for batch-to-batch variability with respect to sensitivity, and also to control the sensitivity in formulations within acceptable limits. We used light microscopy of cold-mounted, polished samples to characterize CL-20 at various stages in its life cycle. The evolution of damage from the initial neat crystals of CL-20 to the ready-to-use pressed pellets shows that processing seriously damages the crystals. These crystals are very brittle, and several explanations are proposed.

GAP/CL-20-Based Compound Explosive: A New Booster Formulation Used in a Small-Sized Initiation Network

NASA Astrophysics Data System (ADS)

Yanju, Wei; Jingyu, Wang; Chongwei, An; Hequn, Li; Xiaomu, Wen; Binshuo, Yu

2017-01-01

With ε-2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and glycidyl azide polymer (GAP) as the solid filler and binder, respectively, GAP/CL-20-based compound explosives were designed and prepared. Using micro injection charge technology, the compound explosives were packed into small grooves to explore their application in a small-sized initiation network. The detonation reliability, detonation velocity, mechanical sensitivity, shock sensitivity, and brisance of the explosive were measured and analyzed. The results show that when the solid content of CL-20 is 82 wt%, the explosive charged in the groove has a smooth surface from a macroscopic view. From a microscopic view, a coarse surface is bonded with many CL-20 particles by GAP binder. The GAP/CL-20-based explosive charge successfully generates detonation waves in a groove larger than 0.6 mm × 0.6 mm. When the charge density in the groove is 1.68 g.cm-3 (90% theoretical maximum density), the detonation velocity reaches 7,290 m.s-1. Moreover, this kind of explosive is characterized by low impact and shock sensitivity.

Diagnostic power of laboratory tests for hereditary spherocytosis: a comparison study in 150 patients grouped according to molecular and clinical characteristics

PubMed Central

Bianchi, Paola; Fermo, Elisa; Vercellati, Cristina; Marcello, Anna P.; Porretti, Laura; Cortelezzi, Agostino; Barcellini, Wilma; Zanella, Alberto

2012-01-01

Background The laboratory diagnosis of hereditary spherocytosis commonly relies on NaCl-based or glycerol-based red cell osmotic fragility tests; more recently, an assay directly targeting the hereditary spherocytosis molecular defect (eosin-5′-maleimide-binding test) has been proposed. None of the available tests identifies all cases of hereditary spherocytosis. Design and Methods We compared the performances of the eosin-5′-maleimide-binding test, NaCl-osmotic fragility studies on fresh and incubated blood, the glycerol lysis test, the acidified glycerol lysis test, and the Pink test on a series of 150 patients with hereditary spherocytosis grouped according to clinical phenotype and the defective protein, with the final aim of finding the combination of tests associated with the highest diagnostic power, even in the mildest cases of hereditary spherocytosis. Results The eosin-5′-maleimide-binding test had a sensitivity of 93% and a specificity of 98% for detecting hereditary spherocytosis: the sensitivity was independent of the type and amount of molecular defect and of the clinical phenotype. The acidified glycerol lysis test and Pink test showed comparable sensitivity (95% and 91%). The sensitivity of NaCl osmotic fragility tests, commonly considered the gold standard for the diagnosis of hereditary spherocytosis, was 68% on fresh blood and 81% on incubated blood, and further decreased in compensated cases (53% and 64%, respectively). The combination of the eosin-5′-maleimide-binding test and acidified glycerol lysis test enabled all patients with hereditary spherocytosis to be identified. The eosin-5′-maleimide-binding test showed the greatest disease specificity. Conclusions Each type of test fails to diagnose some cases of hereditary spherocytosis. The association of an eosin-5′-maleimide-binding test and an acidified glycerol lysis test enabled identification of all patients with hereditary spherocytosis in this series and, therefore, represents a currently effective diagnostic strategy for hereditary spherocytosis including mild/compensated cases. PMID:22058213

Chlorine as a primary radical: evaluation of methods to understand its role in initiation of oxidative cycles

NASA Astrophysics Data System (ADS)

Young, C. J.; Washenfelder, R. A.; Edwards, P. M.; Parrish, D. D.; Gilman, J. B.; Kuster, W. C.; Mielke, L. H.; Osthoff, H. D.; Tsai, C.; Pikelnaya, O.; Stutz, J.; Veres, P. R.; Roberts, J. M.; Griffith, S.; Dusanter, S.; Stevens, P. S.; Flynn, J.; Grossberg, N.; Lefer, B.; Holloway, J. S.; Peischl, J.; Ryerson, T. B.; Atlas, E. L.; Blake, D. R.; Brown, S. S.

2014-04-01

The role of chlorine atoms (Cl) in atmospheric oxidation has been traditionally thought to be limited to the marine boundary layer, where they are produced through heterogeneous reactions involving sea salt. However, recent observation of photolytic Cl precursors (ClNO2 and Cl2) formed from anthropogenic pollution has expanded the potential importance of Cl to include coastal and continental urban areas. Measurements of ClNO2 in Los Angeles during CalNex (California Nexus - Research at the Nexus of Air Quality and Climate Change) showed it to be an important primary (first generation) radical source. Evolution of ratios of volatile organic compounds (VOCs) has been proposed as a method to quantify Cl oxidation, but we find no evidence from this approach for a significant role of Cl oxidation in Los Angeles. We use a box model with the Master Chemical Mechanism (MCM v3.2) chemistry scheme, constrained by observations in Los Angeles, to examine the Cl sensitivity of commonly used VOC ratios as a function of NOx and secondary radical production. Model results indicate VOC tracer ratios could not detect the influence of Cl unless the ratio of [OH] to [Cl] was less than 200 for at least a day. However, the model results also show that secondary (second generation) OH production resulting from Cl oxidation of VOCs is strongly influenced by NOx, and that this effect obscures the importance of Cl as a primary oxidant. Calculated concentrations of Cl showed a maximum in mid-morning due to a photolytic source from ClNO2 and loss primarily to reactions with VOCs. The [OH] to [Cl] ratio was below 200 for approximately 3 h in the morning, but Cl oxidation was not evident from the measured ratios of VOCs. Instead, model simulations show that secondary OH production causes VOC ratio evolution to follow that expected for OH oxidation, despite the significant input of primary Cl from ClNO2 photolysis in the morning. Even though OH is by far the dominant oxidant in Los Angeles, Cl atoms do play an important role in photochemistry there, constituting 9% of the primary radical source. Furthermore, Cl-VOC reactivity differs from that of OH, being more than an order of magnitude larger and dominated by VOCs, such as alkanes, that are less reactive toward OH. Primary Cl is also slightly more effective as a radical source than primary OH due to its greater propensity to initiate radical propagation chains via VOC reactions relative to chain termination via reaction with nitrogen oxides.

An aptamer-based immunoassay in microchannels of a portable analyzer for detection of microcystin-leucine-arginine.

PubMed

Xiang, An; Lei, Xiaoying; Ren, Fengling; Zang, Liuqin; Wang, Qin; Zhang, Ju; Lu, Zifan; Guo, Yanhai

2014-12-01

The rapid detection of microcystin-leucine-arginine (MC-LR), the most highly toxic among MCs, is significantly important to environmental and human health protection and prevention of MC-LR from being used as a bioweapon. Although aptamers offer higher affinity, specificity, and stability with MC-LR than antibodies in the immunodetection of MC-LR due to steric hindrance between two antibodies and limited epitopes of MC-LR for use in a sandwich immunoassay, no sandwich immunoassay using an aptmer has been developed for MC-LR detection. This study is aimed at developing an aptamer-antibody immunoassay (AAIA) to detect MC-LR using a portable analyzer. The aptamers were immobilized onto the glass surface of a microchamber to capture MC-LR. MC-LR and horseradish peroxidase (HRP)-labeled antibody were pulled into the microchamber to react with the immobilized aptamer. The chemiluminescence (CL) catalyzed by HRP was tested by a photodiode-based portable analyzer. MC-LR at 0.5-4.0 μg/L was detected quantitatively by the AAIA, with a CL signal sensitivity of 0.3 μg/L. The assay took less than 35 min for a single sample and demonstrated a high specificity, detecting only MC-LR, but not MC-LA, MC-YR, or nodularin-R. The recovery of two spiked real environmental samples calculated as 94.5-112.7%. Therefore, this AAIA was proved to be a rapid and simple method to detect MC-LR in the field by a single analyst. Copyright © 2014 Elsevier B.V. All rights reserved.

Pest controllers: a high-risk group for Multiple Chemical Sensitivity (MCS)?

PubMed

Bornschein, Susanne; Hausteiner, Constanze; Pohl, Corina; Jahn, Thomas; Angerer, Jürgen; Foerstl, Hans; Zilker, Thomas

2008-03-01

Based on the assumption that professional groups with frequent chemical exposure are at an increased risk for developing Multiple Chemical Sensitivity (MCS), a sample of 45 professional pest controllers was investigated. The examination of the pest controllers consisted of a physical and laboratory examination with urine screening for pyrethroid metabolites, a psychiatric interview, a neuropsychological test battery, and a chemical sensitivity questionnaire. Persistent or serious work related health problems and chemical sensitivity were not reported. In urine, cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (Br(2)CA) was detected in 11%, 4-fluoro-3-phenoxybenzoic acid (F-PBA) in 7%. 3-phenoxybenzoic acid (3-PBA) exceeded the reference range in 9%, cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid (Cl(2)CA) in 20%. Increased liver enzymes and blood count deviations were rather common. 38% had psychiatric disorders. With few exceptions, neuropsychological testing results were normal. The results do not support the hypothesis that work-related insecticide exposure promotes chemical sensitivity.

A sensitive, selective and rapid determination of lead(II) ions in real-life samples using an electrochemically reduced graphene oxide-graphite reinforced carbon electrode.

PubMed

Hamsawahini, Kunashegaran; Sathishkumar, Palanivel; Ahamad, Rahmalan; Yusoff, Abdull Rahim Mohd

2015-11-01

In this study, a sensitive and cost-effective electrochemically reduced graphene oxide (ErGO) on graphite reinforced carbon (GRC) was developed for the detection of lead (Pb(II)) ions present in the real-life samples. A film of graphene oxide (GO) was drop-casted on GRC and their electrochemical properties were investigated using cyclic voltammetry (CV), amperometry and square wave voltammetry (SWV). Factors influencing the detection of Pb(II) ions, such as grades of GRC, constant applied cathodic potential (CACP), concentration of hydrochloric acid and drop-casting drying time were optimised. GO is irreversibly reduced in the range of -0.7 V to -1.6 V vs Ag/AgCl (3 M) in acidic condition. The results showed that the reduction behaviour of GO contributed to the high sensitivity of Pb(II) ions detection even at nanomolar level. The ErGO-GRC showed the detection limit of 0.5 nM and linear range of 3-15 nM in HCl (1 M). The developed electrode has potential to be a good candidate for the determination of Pb(II) ions in different aqueous system. The proposed method gives a good recovery rate of Pb(II) ions in real-life water samples such as tap water and river water. Copyright © 2015 Elsevier B.V. All rights reserved.

Development of an accurate, sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multi-element analysis (chlorine, sulfur, and heavy metals) in coal samples.

PubMed

Boulyga, Sergei F; Heilmann, Jens; Prohaska, Thomas; Heumann, Klaus G

2007-10-01

A method for the direct multi-element determination of Cl, S, Hg, Pb, Cd, U, Br, Cr, Cu, Fe, and Zn in powdered coal samples has been developed by applying inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with laser-assisted introduction into the plasma. A sector-field ICP-MS with a mass resolution of 4,000 and a high-ablation rate laser ablation system provided significantly better sensitivity, detection limits, and accuracy compared to a conventional laser ablation system coupled with a quadrupole ICP-MS. The sensitivity ranges from about 590 cps for (35)Cl+ to more than 6 x 10(5) cps for (238)U+ for 1 microg of trace element per gram of coal sample. Detection limits vary from 450 ng g(-1) for chlorine and 18 ng g(-1) for sulfur to 9.5 pg g(-1) for mercury and 0.3 pg g(-1) for uranium. Analyses of minor and trace elements in four certified reference materials (BCR-180 Gas Coal, BCR-331 Steam Coal, SRM 1632c Trace Elements in Coal, SRM 1635 Trace Elements in Coal) yielded good agreement of usually not more than 5% deviation from the certified values and precisions of less than 10% relative standard deviation for most elements. Higher relative standard deviations were found for particular elements such as Hg and Cd caused by inhomogeneities due to associations of these elements within micro-inclusions in coal which was demonstrated for Hg in SRM 1635, SRM 1632c, and another standard reference material (SRM 2682b, Sulfur and Mercury in Coal). The developed LA-ICP-IDMS method with its simple sample pretreatment opens the possibility for accurate, fast, and highly sensitive determinations of environmentally critical contaminants in coal as well as of trace impurities in similar sample materials like graphite powder and activated charcoal on a routine basis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nauntofte, B.; Poulsen, J.H.

Stimulation-induced changes in Cl content and O2 consumption of collagenase-isolated rat parotid acini were measured. In <10 s, carbachol caused a net Cl efflux, corresponding to approx.50% of the Cl content, and increased the O2 uptake by 100%. The increase was inhibitable by ouabain and was dependent on the presence of extracellular CaS . Furosemide reduced the unstimulated TWCl uptake and prevented the reuptake of Cl after carbachol-induced release. This suggests that a cotransport system is operating in both the unstimulated and stimulated states. Furthermore, furosemide inhibited the stimulated ouabain-sensitive OS uptake. Raising intracellular CaS by the calcium ionophore A23187more » evoked the same pattern of Cl loss and O2 uptake as carboachol. Our results ae compatible with the following hypothesis. Carbachol raises intracellular CaS , causing an increased Cl permeability of the luminal membrane, resulting in a net Cl efflux. A subsequently enhanced influx of Cl and Na via a furosemide-sensitive cotransport system increases intracellular Na . This stimulates the Na -K -ATPase and thereby the OS consumption.« less

N-ethylmaleimide activates a Cl(-)-independent component of K(+) flux in mouse erythrocytes.

PubMed

Shmukler, Boris E; Hsu, Ann; Alves, Jessica; Trudel, Marie; Rust, Marco B; Hubner, Christian A; Rivera, Alicia; Alper, Seth L

2013-06-01

The K-Cl cotransporters (KCCs) of mouse erythrocytes exhibit higher basal activity than those of human erythrocytes, but are similarly activated by cell swelling, by hypertonic urea, and by staurosporine. However, the dramatic stimulation of human erythroid KCCs by N-ethylmaleimide (NEM) is obscured in mouse erythrocytes by a prominent NEM-stimulated K(+) efflux that lacks Cl(-)-dependence. The NEM-sensitivity of Cl(-)-independent K(+) efflux of mouse erythrocytes is lower than that of KCC. The genetically engineered absence of the K-Cl cotransporters KCC3 and KCC1 from mouse erythrocytes does not modify Cl(-)-independent K(+) efflux. Mouse erythrocytes genetically devoid of the Gardos channel KCNN4 show increased NEM-sensitivity of both Cl(-)-independent K(+) efflux and K-Cl cotransport. The increased NEM-sensitivity and stimulation magnitude of Cl(-)-independent K(+) efflux in mouse erythrocytes expressing transgenic hypersickling human hemoglobin SAD (HbSAD) are independent of the presence of KCC3 and KCC1, but absence of KCNN4 reduces the stimulatory effect of HbSAD. NEM-stimulated Cl(-)-independent K(+) efflux of mouse red cells is insensitive to ouabain and bumetanide, but partially inhibited by chloroquine, barium, and amiloride. The NEM-stimulated activity is modestly reduced at pH6.0 but not significantly altered at pH8.0, and is abolished at 0°C. Although the molecular identity of this little-studied K(+) efflux pathway of mouse erythrocytes remains unknown, its potential role in the pathophysiology of sickle red cell dehydration will be important for the extrapolation of studies in mouse models of sickle cell disease to our understanding of humans with sickle cell anemia. Copyright © 2013 Elsevier Inc. All rights reserved.

A highly selective chemiluminescent probe for the detection of chromium(VI)

NASA Astrophysics Data System (ADS)

Jin, Yan; Sun, Yonghua; Li, Chongying; Yang, Chao

2018-03-01

In present work, rhodamine B hydrazide and rhodamine 6G hydrazide were synthesized and the chemiluminescence performance has been investigated. Based on the chemiluminescence of rhodamine 6G hydrazide-chromium(VI), a selective and sensitive method for the direct detection of chromium(VI) was developed. The chemiluminescence intensity was linearly related to the concentration of chromium(VI) in the range of 2.60 × 10- 8-8.00 × 10- 6 mol/L with a correlation coefficient of r = 0.998 and a detection limit of 1.4 × 10- 8 mol/L (S/N = 3). The results indicated rhodamine 6G hydrazide was an excellent chemiluminescent probe for chromium(VI) without reduction of chromium(VI) to chromium(III). A possible mechanism of CL emission was also suggested.

A highly fluorescent hydrophilic ionic liquid as a potential probe for the sensing of biomacromolecules.

PubMed

Chen, Xu-Wei; Liu, Jia-Wei; Wang, Jian-Hua

2011-02-17

With respect to the conventional imidazolium ionic liquids which generally create very weak fluorescence with quantum yields at extremely low levels of 0.005-0.02, a symmetrical hydrophilic ionic liquid 1,3-butylimidazolium chloride (BBimCl) was found to be highly fluorescent with λ(em) at 388 nm when excited at λ(ex) < 340 nm. The very high quantum yield of BBimCl in aqueous medium, derived to be 0.523 when excited at 315 nm, was attributed to its symmetrical plane conjugating structure. In the presence of hemoglobin, the fluorescence of BBimCl could be significantly quenched, resulting from the coordinating interaction between the iron atom in the heme group of hemoglobin and the cationic imidazolium moiety. This feature of the present hydrophilic ionic liquid makes it a promising fluorescence probe candidate for the sensitive sensing of hemoglobin. A linear regression was observed within 3 × 10(-7) to 5 × 10(-6) mol L(-1) for hemoglobin, and a detection limit of 7.3 × 10(-8) mol L(-1) was derived.

Comparison of the CT OligoGen kit with cobas 4800 assay for detection of Chlamydia trachomatis.

PubMed

Parra-Sánchez, Manuel; Marcuello-López, Ana; García-Rey, Silvia; Zakariya-Yousef, Ismail; Sivianes-Valdecantos, Nieves; Sierra-Atienza, Celestina; Bernal-Martínez, Samuel; Pueyo-Rodrígez, Isabel; Martín-Mazuelos, Estrella; Palomares-Folía, José Carlos

2015-12-01

A prospective study was designed to assess the performance of the new CT OligoGen kit and the cobas 4800 assay for detection of Chlamydia trachomatis. A set of samples that included urine samples (n=212), endocervical (n=167), rectal (n=53), pharyngeal (n=7) and urethral swabs (n=3). The samples were sent from a regional sexually transmitted diseases (STD) clinic in Seville, Spain, and were collected from 261 men and 181 women. Discordant results were re-analyzed and clinical data and other tests were reviewed in order to resolve them. Sensitivity, specificity, positive predicative value (PPV), negative predictive value (NPV) and kappa value for C. trachomatis detection using the CT OligoGen kit were 98.5%, 100%, 100%, 95.4% and 0.97, respectively. This new kit had a high sensitivity, specificity, PPV and NPV for C. trachomatis, therefore the performance profile confirms the usefulness and reliable results of this new assay. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Peptides derivatized with bicyclic quaternary ammonium ionization tags. Sequencing via tandem mass spectrometry.

PubMed

Setner, Bartosz; Rudowska, Magdalena; Klem, Ewelina; Cebrat, Marek; Szewczuk, Zbigniew

2014-10-01

Improving the sensitivity of detection and fragmentation of peptides to provide reliable sequencing of peptides is an important goal of mass spectrometric analysis. Peptides derivatized by bicyclic quaternary ammonium ionization tags: 1-azabicyclo[2.2.2]octane (ABCO) or 1,4-diazabicyclo[2.2.2]octane (DABCO), are characterized by an increased detection sensitivity in electrospray ionization mass spectrometry (ESI-MS) and longer retention times on the reverse-phase (RP) chromatography columns. The improvement of the detection limit was observed even for peptides dissolved in 10 mM NaCl. Collision-induced dissociation tandem mass spectrometry of quaternary ammonium salts derivatives of peptides showed dominant a- and b-type ions, allowing facile sequencing of peptides. The bicyclic ionization tags are stable in collision-induced dissociation experiments, and the resulted fragmentation pattern is not significantly influenced by either acidic or basic amino acid residues in the peptide sequence. Obtained results indicate the general usefulness of the bicyclic quaternary ammonium ionization tags for ESI-MS/MS sequencing of peptides. Copyright © 2014 John Wiley & Sons, Ltd.

Hydrogen peroxide sensor based on carbon nanowalls grown by plasma-enhanced chemical vapor deposition

NASA Astrophysics Data System (ADS)

Tomatsu, Masakazu; Hiramatsu, Mineo; Foord, John S.; Kondo, Hiroki; Ishikawa, Kenji; Sekine, Makoto; Takeda, Keigo; Hori, Masaru

2017-06-01

Fabrication of an electrochemical sensor for hydrogen peroxide (H2O2) detection was demonstrated. H2O2 is a major messenger molecule in various redox-dependent cellular signaling transductions. Therefore, sensitive detection of H2O2 is greatly important in health inspection and environmental protection. Carbon nanowalls (CNWs) are composed of few-layer graphenes standing almost vertically on a substrate forming a three-dimensional structure. In this work, CNWs were used as a platform for H2O2 sensing, which is based on the large surface area of conducting carbon and surface decoration with platinum (Pt) nanoparticles (NPs). CNWs were grown on carbon fiber paper (CFP) by inductively coupled plasma-enhanced chemical vapor deposition to increase the surface area. Then, the CNW surface was decorated with Pt-NPs by the reduction of H2PtCl6. Cyclic voltammetry results indicate that the Pt-decorated CNW/CFP electrode possesses excellent electrocatalytic activity for the reduction of H2O2. Amperometric responses indicate the high-sensitivity detection capability of the Pt-decorated CNW/CFP electrode for H2O2.

Density-based parallel skin lesion border detection with webCL

PubMed Central

2015-01-01

Background Dermoscopy is a highly effective and noninvasive imaging technique used in diagnosis of melanoma and other pigmented skin lesions. Many aspects of the lesion under consideration are defined in relation to the lesion border. This makes border detection one of the most important steps in dermoscopic image analysis. In current practice, dermatologists often delineate borders through a hand drawn representation based upon visual inspection. Due to the subjective nature of this technique, intra- and inter-observer variations are common. Because of this, the automated assessment of lesion borders in dermoscopic images has become an important area of study. Methods Fast density based skin lesion border detection method has been implemented in parallel with a new parallel technology called WebCL. WebCL utilizes client side computing capabilities to use available hardware resources such as multi cores and GPUs. Developed WebCL-parallel density based skin lesion border detection method runs efficiently from internet browsers. Results Previous research indicates that one of the highest accuracy rates can be achieved using density based clustering techniques for skin lesion border detection. While these algorithms do have unfavorable time complexities, this effect could be mitigated when implemented in parallel. In this study, density based clustering technique for skin lesion border detection is parallelized and redesigned to run very efficiently on the heterogeneous platforms (e.g. tablets, SmartPhones, multi-core CPUs, GPUs, and fully-integrated Accelerated Processing Units) by transforming the technique into a series of independent concurrent operations. Heterogeneous computing is adopted to support accessibility, portability and multi-device use in the clinical settings. For this, we used WebCL, an emerging technology that enables a HTML5 Web browser to execute code in parallel for heterogeneous platforms. We depicted WebCL and our parallel algorithm design. In addition, we tested parallel code on 100 dermoscopy images and showed the execution speedups with respect to the serial version. Results indicate that parallel (WebCL) version and serial version of density based lesion border detection methods generate the same accuracy rates for 100 dermoscopy images, in which mean of border error is 6.94%, mean of recall is 76.66%, and mean of precision is 99.29% respectively. Moreover, WebCL version's speedup factor for 100 dermoscopy images' lesion border detection averages around ~491.2. Conclusions When large amount of high resolution dermoscopy images considered in a usual clinical setting along with the critical importance of early detection and diagnosis of melanoma before metastasis, the importance of fast processing dermoscopy images become obvious. In this paper, we introduce WebCL and the use of it for biomedical image processing applications. WebCL is a javascript binding of OpenCL, which takes advantage of GPU computing from a web browser. Therefore, WebCL parallel version of density based skin lesion border detection introduced in this study can supplement expert dermatologist, and aid them in early diagnosis of skin lesions. While WebCL is currently an emerging technology, a full adoption of WebCL into the HTML5 standard would allow for this implementation to run on a very large set of hardware and software systems. WebCL takes full advantage of parallel computational resources including multi-cores and GPUs on a local machine, and allows for compiled code to run directly from the Web Browser. PMID:26423836

Density-based parallel skin lesion border detection with webCL.

PubMed

Lemon, James; Kockara, Sinan; Halic, Tansel; Mete, Mutlu

2015-01-01

Dermoscopy is a highly effective and noninvasive imaging technique used in diagnosis of melanoma and other pigmented skin lesions. Many aspects of the lesion under consideration are defined in relation to the lesion border. This makes border detection one of the most important steps in dermoscopic image analysis. In current practice, dermatologists often delineate borders through a hand drawn representation based upon visual inspection. Due to the subjective nature of this technique, intra- and inter-observer variations are common. Because of this, the automated assessment of lesion borders in dermoscopic images has become an important area of study. Fast density based skin lesion border detection method has been implemented in parallel with a new parallel technology called WebCL. WebCL utilizes client side computing capabilities to use available hardware resources such as multi cores and GPUs. Developed WebCL-parallel density based skin lesion border detection method runs efficiently from internet browsers. Previous research indicates that one of the highest accuracy rates can be achieved using density based clustering techniques for skin lesion border detection. While these algorithms do have unfavorable time complexities, this effect could be mitigated when implemented in parallel. In this study, density based clustering technique for skin lesion border detection is parallelized and redesigned to run very efficiently on the heterogeneous platforms (e.g. tablets, SmartPhones, multi-core CPUs, GPUs, and fully-integrated Accelerated Processing Units) by transforming the technique into a series of independent concurrent operations. Heterogeneous computing is adopted to support accessibility, portability and multi-device use in the clinical settings. For this, we used WebCL, an emerging technology that enables a HTML5 Web browser to execute code in parallel for heterogeneous platforms. We depicted WebCL and our parallel algorithm design. In addition, we tested parallel code on 100 dermoscopy images and showed the execution speedups with respect to the serial version. Results indicate that parallel (WebCL) version and serial version of density based lesion border detection methods generate the same accuracy rates for 100 dermoscopy images, in which mean of border error is 6.94%, mean of recall is 76.66%, and mean of precision is 99.29% respectively. Moreover, WebCL version's speedup factor for 100 dermoscopy images' lesion border detection averages around ~491.2. When large amount of high resolution dermoscopy images considered in a usual clinical setting along with the critical importance of early detection and diagnosis of melanoma before metastasis, the importance of fast processing dermoscopy images become obvious. In this paper, we introduce WebCL and the use of it for biomedical image processing applications. WebCL is a javascript binding of OpenCL, which takes advantage of GPU computing from a web browser. Therefore, WebCL parallel version of density based skin lesion border detection introduced in this study can supplement expert dermatologist, and aid them in early diagnosis of skin lesions. While WebCL is currently an emerging technology, a full adoption of WebCL into the HTML5 standard would allow for this implementation to run on a very large set of hardware and software systems. WebCL takes full advantage of parallel computational resources including multi-cores and GPUs on a local machine, and allows for compiled code to run directly from the Web Browser.

Mosquitocidal properties of IgG targeting the glutamate-gated chloride channel in three mosquito disease vectors (Diptera: Culicidae).

PubMed

Meyers, Jacob I; Gray, Meg; Foy, Brian D

2015-05-15

The glutamate-gated chloride channel (GluCl) is a highly sensitive insecticide target of the avermectin class of insecticides. As an alternative to using chemical insecticides to kill mosquitoes, we tested the effects of purified immunoglobulin G (IgG) targeting the extracellular domain of GluCl from Anopheles gambiae (AgGluCl) on the survivorship of three key mosquito disease vectors: Anopheles gambiae s.s., Aedes aegypti and Culex tarsalis. When administered through a single blood meal, anti-AgGluCl IgG reduced the survivorship of A. gambiae in a dose-dependent manner (LC50: 2.82 mg ml(-1), range 2.68-2.96 mg ml(-1)) but not A. aegypti or C. tarsalis. We previously demonstrated that AgGluCl is only located in tissues of the head and thorax of A. gambiae. To verify that AgGluCl IgG is affecting target antigens found outside the midgut, we injected it directly into the hemocoel via intrathoracic injection. A single, physiologically relevant concentration of anti-AgGluCl IgG injected into the hemocoel equally reduced mosquito survivorship of all three species. To test whether anti-AgGluCl IgG was entering the hemocoel of each of these mosquitoes, we fed mosquitoes a blood meal containing anti-AgGluCl IgG and subsequently extracted their hemolymph. We only detected IgG in the hemolymph of A. gambiae, suggesting that resistance of A. aegypti and C. tarsalis to anti-AgGluCl IgG found in blood meals is due to deficient IgG translocation across the midgut. We predicted that anti-AgGluCl IgG's mode of action is by antagonizing GluCl activity. To test this hypothesis, we fed A. gambiae blood meals containing anti-AgGluCl IgG and the GluCl agonist ivermectin (IVM). Anti-AgGluCl IgG attenuated the mosquitocidal effects of IVM, suggesting that anti-AgGluCl IgG antagonizes IVM-induced activation of GluCl. Lastly, we stained adult, female A. aegypti and C. tarsalis for GluCl expression. Neuronal GluCl expression in these mosquitoes was similar to previously reported A. gambiae GluCl expression; however, we also discovered GluCl staining on the basolateral surface of their midgut epithelial cells, suggesting important physiological differences in Culicine and Anopheline mosquitoes. © 2015. Published by The Company of Biologists Ltd.

Mosquitocidal properties of IgG targeting the glutamate-gated chloride channel in three mosquito disease vectors (Diptera: Culicidae)

PubMed Central

Meyers, Jacob I.; Gray, Meg; Foy, Brian D.

2015-01-01

ABSTRACT The glutamate-gated chloride channel (GluCl) is a highly sensitive insecticide target of the avermectin class of insecticides. As an alternative to using chemical insecticides to kill mosquitoes, we tested the effects of purified immunoglobulin G (IgG) targeting the extracellular domain of GluCl from Anopheles gambiae (AgGluCl) on the survivorship of three key mosquito disease vectors: Anopheles gambiae s.s., Aedes aegypti and Culex tarsalis. When administered through a single blood meal, anti-AgGluCl IgG reduced the survivorship of A. gambiae in a dose-dependent manner (LC50: 2.82 mg ml−1, range 2.68–2.96 mg ml−1) but not A. aegypti or C. tarsalis. We previously demonstrated that AgGluCl is only located in tissues of the head and thorax of A. gambiae. To verify that AgGluCl IgG is affecting target antigens found outside the midgut, we injected it directly into the hemocoel via intrathoracic injection. A single, physiologically relevant concentration of anti-AgGluCl IgG injected into the hemocoel equally reduced mosquito survivorship of all three species. To test whether anti-AgGluCl IgG was entering the hemocoel of each of these mosquitoes, we fed mosquitoes a blood meal containing anti-AgGluCl IgG and subsequently extracted their hemolymph. We only detected IgG in the hemolymph of A. gambiae, suggesting that resistance of A. aegypti and C. tarsalis to anti-AgGluCl IgG found in blood meals is due to deficient IgG translocation across the midgut. We predicted that anti-AgGluCl IgG's mode of action is by antagonizing GluCl activity. To test this hypothesis, we fed A. gambiae blood meals containing anti-AgGluCl IgG and the GluCl agonist ivermectin (IVM). Anti-AgGluCl IgG attenuated the mosquitocidal effects of IVM, suggesting that anti-AgGluCl IgG antagonizes IVM-induced activation of GluCl. Lastly, we stained adult, female A. aegypti and C. tarsalis for GluCl expression. Neuronal GluCl expression in these mosquitoes was similar to previously reported A. gambiae GluCl expression; however, we also discovered GluCl staining on the basolateral surface of their midgut epithelial cells, suggesting important physiological differences in Culicine and Anopheline mosquitoes. PMID:25994632

Potato plants (Solanum tuberosum L.) are chloride-sensitive: Is this dogma valid?

PubMed

Hütsch, Birgit W; Keipp, Katrin; Glaser, Ann-Kathrin; Schubert, Sven

2018-06-01

Chloride sensitivity of the potato (Solanum tuberosum L.) cultivars Marabel and Désirée was investigated in two pot experiments (soil/sand mixture and hydroponics). It was tested whether there are differential effects of KCl and K 2 SO 4 application on tuber yield and tuber quality, and whether both potato cultivars differ in their chloride sensitivity. Tuber yield, dry matter percentage of the tubers, starch concentration and starch yield were not significantly affected by potassium source (K 2 SO 4 or KCl). After exposure to salt stress in hydroponics (100 mmol L -1 NaCl, 50 mmol L -1 Na 2 SO 4 , 50 mmol L -1 CaCl 2 ) for 5 days, 3-week-old potato plants had significantly reduced shoot dry mass after NaCl and Na 2 SO 4 application. However, CaCl 2 treatment did not significantly affect shoot growth, although the chloride concentration reached 65 to 74 mg Cl - mg -1 dry matter, similar to the NaCl treatment. In contrast, growth reductions were closely related to sodium concentrations, thus plants suffered sodium toxicity and not chloride toxicity. Both potato cultivars are chloride-resistant and can be fertilised with KCl instead of K 2 SO 4 without the risk of depression in tuber yield or tuber quality. The statement that potatoes are chloride-sensitive and that chloride has negative effects on yield performance needs reconsideration. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brock, T.A.; Brugnara, C.; Canessa, M.

The authors have characterized a Na/sup +/-K/sup +/-Cl/sup -/ cotransporter in vascular endothelial cells (EC) cultured from different blood vessels and species that is inhibited by the diuretics furosemide and bumentanide. Inward /sup 86/Rb influx transported by the Na/sup +/-K/sup +/ pump in cultured EC from bovine and pig aorta, bovine vena cava, and baboon cephalic vein but not in human umbilical or saphenous vein EC. External Na/sup +/ or Cl/sup -/-stimulated, ouabain-insensitive /sup 86/Rb influx is equal to furosemide or bumetanide-sensitive /sup 86/Rb influx. Ouabain-insensitive /sup 22/Na influx is also partially inhibited by these drugs and stimulated by increasingmore » external K/sup +/ or Cl/sup -/. Net Na/sup +/ extrusion occurs via the Na/sup +/-K/sup +/-Cl/sup -/ cotransporter in the absence of external K/sup +/, whereas net Na/sup +/ influx occurs at higher external K/sup +/. Maximal concentrations (100 nM) of bradykinin and vasopressin increase the initial rate of bumetanide-sensitive /sup 86/Rb influx by approx.60 and 70%. Addition of either ethyleneglycol-bis(..beta..-aminotethylether)-N,N'-tetraacetic acid or LaCl/sub 3/ (to block calcium influx) prevents bradykinin-stimulated /sup 86/Rb influx. When intracellular calcium is elevated using ionomycin (100 nM), a Ca/sup 2 +/ionophore, bumetanide-sensitive /sup 86/Rb influx increases approx.twofold. In contrast, isoproterenol (100 ..mu..M) and forskolin (50 /sup +/M), adenylate cyclase stimulators, decrease furosemide-sensitive /sup 86/Rb influx. Thus in certain types of cultured EC, a Na/sup +/-K/sup +/-Cl/sup -/ cotransporter mediates a fraction of K/sup +/ influx quantitatively as important as the Na/sup +/-K/sup +/ pump (ouabain-sensitive /sup 86/Rb influx) and appears to be modulated by Ca/sup 2 +/ and cyclic nucleotides.« less

A novel sandwich-type electrochemical aptasensor based on GR-3D Au and aptamer-AuNPs-HRP for sensitive detection of oxytetracycline.

PubMed

Liu, Su; Wang, Yu; Xu, Wei; Leng, Xueqi; Wang, Hongzhi; Guo, Yuna; Huang, Jiadong

2017-02-15

In this paper, a novel sandwich-type electrochemical aptasensor has been fabricated and applied for sensitive and selective detection of antibiotic oxytetracycline (OTC). This sensor was based on graphene-three dimensional nanostructure gold nanocomposite (GR-3D Au) and aptamer-AuNPs-horseradish peroxidase (aptamer-AuNPs-HRP) nanoprobes as signal amplification. Firstly, GR-3D Au film was modified on glassy carbon electrode only by one-step electrochemical coreduction with graphite oxide (GO) and HAuCl 4 at cathodic potentials, which enhanced the electron transfer and loading capacity of biomolecules. Then the aptamer and HRP modified Au nanoparticles provide high affinity and ultrasensitive electrochemical probe with excellent specificity for OTC. Under the optimized conditions, the peak current was linearly proportional to the concentration of OTC in the range of 5×10 -10 -2×10 -3 gL -1 , with a detection limit of 4.98×10 -10 gL -1 . Additionally, this aptasensor had the advantages in high sensitivity, superb specificity and showed good recovery in synthetic samples. Hence, the developed sandwich-type electrochemical aptasensor might provide a useful and practical tool for OTC determination and related food safety analysis and clinical diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Theoretical analysis of the formation driving force and decreased sensitivity for CL-20 cocrystals

NASA Astrophysics Data System (ADS)

Zhou, Jun-Hong; Shi, Liang-Wei; Zhang, Chao-Yang; Li, Hong-Zhen; Chen, Min-Bo; Chen, Wei-Ming

2016-07-01

Methods that analyze the driving force in the formation of the new energetic cocrystal are proposed in this paper. Various intermolecular interactions in the 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo [5.5.0.05,9.03,11]dodecane (CL-20) cocrystals are compared with those in pure CL-20 and coformer crystals by atom in molecule (AIM) and Hirshfeld surface methods under the supramolecular cluster model. The driving force in the formation of the CL-20 cocrystals is analyzed. The main driving force in the formation of the cocrystal CL-20/HMX comes from the O···H interactions, that in the formation of the cocrystal CL-20/TNT from the O···H and C···O interactions, and that in the formation of the cocrystal CL-20/BTF from the N···H and N···O interactions. Other interactions in the CL-20 cocrystals only contribute to their stabilization. At the same time, the reasons for the decreased impact sensitivity of the CL-20 cocrystals are also analyzed. They are the strengthening of the intermolecular interactions, the reducing of the free space, and the changing of the surrounding of CL-20 molecule in the CL-20 cocrystals in comparison with those in the pure CL-20 crystal.

Effect of ENaC Modulators on Rat Neural Responses to NaCl

PubMed Central

Mummalaneni, Shobha; Qian, Jie; Phan, Tam-Hao T.; Rhyu, Mee-Ra; Heck, Gerard L.; DeSimone, John A.; Lyall, Vijay

2014-01-01

The effects of small molecule ENaC activators N,N,N-trimethyl-2-((4-methyl-2-((4-methyl-1H-indol-3-yl)thio)pentanoyl)oxy)ethanaminium iodide (Compound 1) and N-(2-hydroxyethyl)-4-methyl-2-((4-methyl-1H-indol-3-yl)thio)pentanamide (Compound 2), were tested on the benzamil (Bz)-sensitive NaCl chorda tympani (CT) taste nerve response under open-circuit conditions and under ±60 mV applied lingual voltage-clamp, and compared with the effects of known physiological activators (8-CPT-cAMP, BAPTA-AM, and alkaline pH), and an inhibitor (ionomycin+Ca2+) of ENaC. The NaCl CT response was enhanced at −60 mV and suppressed at +60 mV. In every case the CT response (r) versus voltage (V) curve was linear. All ENaC activators increased the open-circuit response (ro) and the voltage sensitivity (κ, negative of the slope of the r versus V curve) and ionomycin+Ca2+ decreased ro and κ to zero. Compound 1 and Compound 2 expressed a sigmoidal-saturating function of concentration (0.25–1 mM) with a half-maximal response concentration (k) of 0.49 and 1.05 mM, respectively. Following treatment with 1 mM Compound 1, 8-CPT-cAMP, BAPTA-AM and pH 10.3, the Bz-sensitive NaCl CT response to 100 mM NaCl was enhanced and was equivalent to the Bz-sensitive CT response to 300 mM NaCl. Plots of κ versus ro in the absence and presence of the activators or the inhibitor were linear, suggesting that changes in the affinity of Na+ for ENaC under different conditions are fully compensated by changes in the apical membrane potential difference, and that the observed changes in the Bz-sensitive NaCl CT response arise exclusively from changes in the maximum CT response (rm). The results further suggest that the agonists enhance and ionomycin+Ca2+ decreases ENaC function by increasing or decreasing the rate of release of Na+ from its ENaC binding site to the receptor cell cytosol, respectively. Irrespective of agonist type, the Bz-sensitive NaCl CT response demonstrated a maximum response enhancement limit of about 75% over control value. PMID:24839965

Detecting Airborne Mercury by Use of Gold Nanowires

NASA Technical Reports Server (NTRS)

Ryan, Margaret; Shevade, Abhijit; Kisor, Adam; Homer, Margie; Soler, Jessica; Mung, Nosang; Nix, Megan

2009-01-01

Like the palladium chloride (PdCl2) films described in the immediately preceding article, gold nanowire sensors have been found to be useful for detecting airborne elemental mercury at concentrations on the order of parts per billion (ppb). Also like the PdCl2 films, gold nanowire sensors can be regenerated under conditions much milder than those necessary for regeneration of gold films that have been used as airborne-Hg sensors. The interest in nanowire sensors in general is prompted by the expectation that nanowires of a given material covering a given surface may exhibit greater sensitivity than does a film of the same material because nanowires have a greater surface area. In preparation for experiments to demonstrate this sensor concept, sensors were fabricated by depositing gold nanowires, variously, on microhotplate or microarray sensor substrates. In the experiments, the electrical resistances were measured while the sensors were exposed to air at a temperature of 25 C and relative humidity of about 30 percent containing mercury at various concentrations from 2 to 70 ppb (see figure). The results of this and other experiments have been interpreted as signifying that sensors of this type can detect mercury at ppb concentrations in room-temperature air and can be regenerated by exposure to clean flowing air at temperatures <40 C.

Quantitative Monitoring of Cefradine in Human Urine Using a Luminol/Sulfobutylether-β-Cyclodextrin Chemiluminescence System

NASA Astrophysics Data System (ADS)

Shen, M. X.; Tan, X. J.; Song, Zh. H.

2018-05-01

In this paper, a sensitive, rapid, and simple flow-injection chemiluminescence (FI-CL) technique is described for determining cefradine in human urine and capsule samples at the picogram level. The results show that cefradine within 0.1-100.0 nmol/L quantitatively quenches the CL intensity of the luminol/sulfo butylether-β-cyclodextrin (SBE-β-CD) system, with a relative correlation coefficient r of 0.9931. Subsequently, the possible mechanism for the quenching phenomenon is discussed in detail using the FI-CL and molecular docking methods. The proposed CL method, with a detection limit of 0.03 nmol/L (3σ) and relative standard deviations <3.0% (N = 7), is then implemented to monitor the excretion of cefradine in human urine. After orally administration, the cefradine reaches a maximum value of 1.37 ± 0.02 mg/mL at 2.0 h in urine, and the total excretion is 4.41 ± 0.03 mg/mL within 8.0 h. The absorption rate constant ka, the elimination rate constant ke, and the half-life t1/2 are 0.670 ± 0.008 h-1, 0.744 ± 0.005 h-1, and 0.93 ± 0.05 h, respectively.

Non-covalently anchored multi-walled carbon nanotubes with hexa-decafluorinated zinc phthalocyanine as ppb level chemiresistive chlorine sensor

NASA Astrophysics Data System (ADS)

Sharma, Anshul Kumar; Mahajan, Aman; Bedi, R. K.; Kumar, Subodh; Debnath, A. K.; Aswal, D. K.

2018-01-01

A cost effective solution assembly method has been explored for preparing zinc(II)1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexa-decafluoro-29H,31H-phthalocyanine/multi-walled carbon nanotubes (F16ZnPc/MWCNTs-COOH) hybrid. Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) investigations confirm the non-covalent anchoring of F16ZnPc onto MWCNTs-COOH through п-п stacking interactions. Further, a highly sensitive and selective chemiresistive Cl2 sensor has been fabricated using F16ZnPc/MWCNTs-COOH hybrid. The response of sensor is found to be 21.28% for 2 ppm of Cl2 with a response time of 14 s and theoretical detection limit of the sensor is found down to 0.06 ppb. The improved Cl2 sensing characteristics of hybrid are found to be originated from the synergetic interaction between F16ZnPc and MWCNTs-COOH. The underlying mechanism for improved gas sensing performance of F16ZnPc/MWCNTs-COOH sensor towards Cl2 has been explained using Raman, X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) studies.

First Evidence of pep Solar Neutrinos by Direct Detection in Borexino

NASA Astrophysics Data System (ADS)

Bellini, G.; Benziger, J.; Bick, D.; Bonetti, S.; Bonfini, G.; Bravo, D.; Buizza Avanzini, M.; Caccianiga, B.; Cadonati, L.; Calaprice, F.; Carraro, C.; Cavalcante, P.; Chavarria, A.; Chepurnov, A.; D'Angelo, D.; Davini, S.; Derbin, A.; Etenko, A.; Fomenko, K.; Franco, D.; Galbiati, C.; Gazzana, S.; Ghiano, C.; Giammarchi, M.; Goeger-Neff, M.; Goretti, A.; Grandi, L.; Guardincerri, E.; Hardy, S.; Ianni, Aldo; Ianni, Andrea; Korablev, D.; Korga, G.; Koshio, Y.; Kryn, D.; Laubenstein, M.; Lewke, T.; Litvinovich, E.; Loer, B.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Machulin, I.; Manecki, S.; Maneschg, W.; Manuzio, G.; Meindl, Q.; Meroni, E.; Miramonti, L.; Misiaszek, M.; Montanari, D.; Mosteiro, P.; Muratova, V.; Oberauer, L.; Obolensky, M.; Ortica, F.; Otis, K.; Pallavicini, M.; Papp, L.; Perasso, L.; Perasso, S.; Pocar, A.; Quirk, J.; Raghavan, R. S.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Sabelnikov, A.; Saldanha, R.; Salvo, C.; Schönert, S.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Vignaud, D.; Vogelaar, R. B.; von Feilitzsch, F.; Winter, J.; Wojcik, M.; Wright, A.; Wurm, M.; Xu, J.; Zaimidoroga, O.; Zavatarelli, S.; Zuzel, G.

2012-02-01

We observed, for the first time, solar neutrinos in the 1.0-1.5 MeV energy range. We determined the rate of pep solar neutrino interactions in Borexino to be 3.1±0.6stat±0.3systcounts/(day·100ton). Assuming the pep neutrino flux predicted by the standard solar model, we obtained a constraint on the CNO solar neutrino interaction rate of <7.9counts/(day·100ton) (95% C.L.). The absence of the solar neutrino signal is disfavored at 99.97% C.L., while the absence of the pep signal is disfavored at 98% C.L. The necessary sensitivity was achieved by adopting data analysis techniques for the rejection of cosmogenic C11, the dominant background in the 1-2 MeV region. Assuming the Mikheyev-Smirnov-Wolfenstein large mixing angle solution to solar neutrino oscillations, these values correspond to solar neutrino fluxes of (1.6±0.3)×108cm-2s-1 and <7.7×108cm-2s-1 (95% C.L.), respectively, in agreement with both the high and low metallicity standard solar models. These results represent the first direct evidence of the pep neutrino signal and the strongest constraint of the CNO solar neutrino flux to date.

Intrinsic chemiluminescence production from the degradation of haloaromatic pollutants during environmentally-friendly advanced oxidation processes: Mechanism, structure-activity relationship and potential applications.

PubMed

Zhu, Benzhan; Shen, Chen; Gao, Huiying; Zhu, Liya; Shao, Jie; Mao, Li

2017-12-01

The ubiquitous distribution of halogenated aromatic compounds (XAr) coupled with their carcinogenicity has raised public concerns on their potential risks to both human health and the ecosystem. Recently, advanced oxidation processes (AOPs) have been considered as an "environmentally-friendly" technology for the remediation and destruction of such recalcitrant and highly toxic XAr. During our study on the mechanism of metal-independent production of hydroxyl radicals (OH) by halogenated quinones and H 2 O 2 , we found, unexpectedly, that an unprecedented OH-dependent two-step intrinsic chemiluminescene (CL) can be produced by H 2 O 2 and tetrachloro-p-benzoquinone, the major carcinogenic metabolite of the widely used wood preservative pentachlorophenol. Further investigations showed that, in all OH-generating systems, CL can also be produced not only by pentachlorophenol and all other halogenated phenols, but also by all XAr tested. A systematic structure-activity relationship study for all 19 chlorophenolic congeners showed that the CL increased with an increasing number of Cl-substitution in general. More importantly, a relatively good correlation was observed between the formation of quinoid/semiquinone radical intermediates and CL generation. Based on these results, we propose that OH-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual CL production; and a rapid, sensitive, simple, and effective CL method was developed not only to detect and quantify trace amount of XAr, but also to provide useful information for predicting the toxicity or monitoring real-time degradation kinetics of XAr. These findings may have broad chemical, environmental and biological implications for future studies on halogenated aromatic persistent organic pollutants. Copyright © 2017. Published by Elsevier B.V.

Improved photocurrent of a poly (3,4-ethylenedioxythiophene)-ClO₄⁻/TiO₂ thin film-modified counter electrode for dye-sensitized solar cells.

PubMed

Sakurai, Sho; Kawamata, Yuka; Takahashi, Masashi; Kobayashi, Koichi

2011-01-01

We prepared a poly(3,4-ethylenedioxythiophene) (PEDOT)-ClO₄⁻-supported TiO₂ thin-film electrode as a counter electrode on a transparent conductive oxide glass electrode for a dye-sensitized solar cell (DSSC) using a combination of sol-gel and electropolymerization methods. The photocurrent-voltage characteristics indicate that DSSCs with PEDOT-ClO₄⁻/TiO₂ thin-film counter electrodes had a high photovoltaic conversion efficiency similar to that of PEDOT-ClO₄⁻/TiO₂ particle composite-film electrodes. Furthermore, it was found that the photocurrent was increased by attaching a reflector to the opposite side of the transparent counter electrode.

pH-Sensitive carboxymethyl chitosan-modified cationic liposomes for sorafenib and siRNA co-delivery.

PubMed

Yao, Yao; Su, Zhihui; Liang, Yanchao; Zhang, Na

2015-01-01

Combination of chemotherapeutic drug and small interfering RNA (siRNA) can affect multiple disease pathways and has been proven effective in suppressing tumor progression. Co-delivery of drug and siRNA within a same nanocarrier is a vital means in this field. The present study aimed at the development of a pH-sensitive liposome to co-deliver drug and siRNA to tumor region. Driven by the electrostatic interaction, the pH-sensitive material, carboxymethyl chitosan (CMCS), was coated onto the surface of the cationic liposome (CL) preloaded with sorafenib (Sf) and siRNA (Si). To evaluate whether the resulting CMCS-modified Sf and siRNA co-delivery cationic liposome (CMCS-SiSf-CL) enhanced antitumor efficiency after systematic administration, in vitro and in vivo experiments were evaluated in HepG2 cells and the H22 cells-bearing Kunming mice model. The experimental results demonstrated that CMCS-SiSf-CL was able to condense siRNA efficiently and protect siRNA from being degraded by serum and RNase. The release rate of Sf from CMCS-modified liposome exhibited pH-sensitive release behavior. Furthermore, in vitro cellular uptake results showed that CMCS-SiSf-CL yielded higher fluorescence intensity at pH 6.5 than at pH 7.4, and that siRNA could be delivered to tumor site by CMCS-SiSf-CL in vivo. The in vivo antitumor efficacy showed that CMCS-Sf-CL inhibits tumor growth effectively when compared with free Sf solution. In current experimental conditions, this liposomal formulation did not show significant toxicity both in vitro and in vivo. Therefore, co-delivering Sf with siRNA by CMCS-SiSf-CL might provide a promising approach for tumor therapy.

Chloride ion transport and overexpression of TMEM16A in a guinea-pig asthma model.

PubMed

Kondo, M; Tsuji, M; Hara, K; Arimura, K; Yagi, O; Tagaya, E; Takeyama, K; Tamaoki, J

2017-06-01

TMEM16A, a Ca-activated Cl channel, regulates various physiological functions such as mucin secretion. However, the role of TMEM16A in hyper-secretion in asthma is not fully understood. The aim of this study is to evaluate Cl ion transport via TMEM16A and determine the localization of TMEM16A in a guinea-pig asthma model. Guinea-pigs were sensitized with ovalbumin (OVA) i.p. on Days 1 and 8. On Day 22, we assessed OVA challenge-induced Cl ion transport in the sensitized tracheas ex vivo in an Ussing chamber, compared with the non-sensitized tracheas. We then examined the effect of T16Ainh-A01, a TMEM16A inhibitor, on the increase in Cl ion transport. The tracheal epithelium was immunostained with an anti-TMEM16A antibody. Epithelial cells from guinea-pig tracheas were cultured at the air-liquid interface in the presence of IL-13 for in vitro study. We studied the effect of TMEM16A inhibitors on Ca-dependent agonist, uridine triphosphate (UTP)-induced increases in Cl ion transport in the cultured cells. The cells were immunostained with an anti-TMEM16A antibody, an anti-MUC5AC antibody and an anti-α-tubulin antibody. OVA challenge induced an increase in short circuit current within 1 min in the OVA-sensitized tracheas but not in the non-sensitized tracheas, which was inhibited by pretreatment of T16Ainh-A01. Sensitized tracheas showed goblet cell metaplasia with more positive TMEM16A immunostaining, particularly in the apical portion compared with the non-sensitized tracheas. The in vitro UTP-induced increase in Cl ion transport was strongly inhibited by pretreatment with T16Ainh-A01, benzbromarone, and niflumic acid. TMEM16A was positively immunostained at the apical portion and in the MUC5AC-positive area in IL-13-induced goblet cell metaplasia. Antigen challenge and Ca-dependent agonist treatment increased Cl ion transport via the overexpression of TMEM16A in goblet cell metaplasia in a guinea-pig asthma model. TMEM16A inhibitors may be useful for the treatment of hyper-secretion in asthma. © 2017 John Wiley & Sons Ltd.

The applicability of real-time PCR in the diagnostic of cutaneous leishmaniasis and parasite quantification for clinical management: Current status and perspectives.

PubMed

Moreira, Otacilio C; Yadon, Zaida E; Cupolillo, Elisa

2017-09-29

Cutaneous leishmaniasis (CL) is spread worldwide and is the most common manifestation of leishmaniasis. Diagnosis is performed by combining clinical and epidemiological features, and through the detection of Leishmania parasites (or DNA) in tissue specimens or trough parasite isolation in culture medium. Diagnosis of CL is challenging, reflecting the pleomorphic clinical manifestations of this disease. Skin lesions vary in severity, clinical appearance, and duration, and in some cases, they can be indistinguishable from lesions related to other diseases. Over the past few decades, PCR-based methods, including real-time PCR assays, have been developed for Leishmania detection, quantification and species identification, improving the molecular diagnosis of CL. This review provides an overview of many real-time PCR methods reported for the diagnostic evaluation of CL and some recommendations for the application of these methods for quantification purposes for clinical management and epidemiological studies. Furthermore, the use of real-time PCR for Leishmania species identification is also presented. The advantages of real-time PCR protocols are numerous, including increased sensitivity and specificity and simpler standardization of diagnostic procedures. However, despite the numerous assays described, there is still no consensus regarding the methods employed. Furthermore, the analytical and clinical validation of CL molecular diagnosis has not followed international guidelines so far. A consensus methodology comprising a DNA extraction protocol with an exogenous quality control and an internal reference to normalize parasite load is still needed. In addition, the analytical and clinical performance of any consensus methodology must be accurately assessed. This review shows that a standardization initiative is essential to guide researchers and clinical laboratories towards the achievement of a robust and reproducible methodology, which will permit further evaluation of parasite load as a surrogate marker of prognosis and monitoring of aetiological treatment, particularly in multi-centric observational studies and clinical trials. Copyright © 2017 Elsevier B.V. All rights reserved.

System-on-fluidics immunoassay device integrating wireless radio-frequency-identification sensor chips.

PubMed

Yazawa, Yoshiaki; Oonishi, Tadashi; Watanabe, Kazuki; Shiratori, Akiko; Funaoka, Sohei; Fukushima, Masao

2014-09-01

A simple and sensitive point-of-care-test (POCT) device for chemiluminescence (CL) immunoassay was devised and tested. The device consists of a plastic flow-channel reactor and two wireless-communication sensor chips, namely, a photo-sensor chip and a temperature-sensor chip. In the flow-channel reactor, a target antigen is captured by an antibody immobilized on the inner wall of the flow-channel and detected with enzyme labeled antibody by using CL substrate. The CL signal corresponding to the amount of antigen is measured by a newly developed radio-frequency-identification (RFID) sensor, which enables batteryless operation and wireless data communication with an external reader. As for the POCT device, its usage environment, especially temperature, varies for each measurement. Hence, temperature compensation is a key issue in regard to eliminating dark-signal fluctuation, which is a major factor in deterioration of the precision of the POCT device. A two-stage temperature-compensation scheme was adopted. As for the first stage, the signals of two photodiodes, one with an open window and one with a sealed window, integrated on the photo-sensor chip are differentiated to delete the dark signal. As for the second stage, the differentiated signal fluctuation caused by a temperature variation is compensated by using the other sensor chip (equipped with a temperature sensor). The dark-level fluctuation caused by temperature was reduced from 0.24 to 0.02 pA/°C. The POCT device was evaluated as a CL immunoassay of thyroid-stimulating hormone (TSH). The flow rate of the CL reagent in the flow channel was optimized. As a result, the detection limit of the POCT device was 0.08 ng/ml (i.e., 0.4 μIU/ml). Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Carbon nanotubes and graphene modified screen-printed carbon electrodes as sensitive sensors for the determination of phytochelatins in plants using liquid chromatography with amperometric detection.

PubMed

Dago, Àngela; Navarro, Javier; Ariño, Cristina; Díaz-Cruz, José Manuel; Esteban, Miquel

2015-08-28

Nanomaterials are of great interest for the development of electrochemical sensors. Multi-walled carbon nanotubes and graphene were used to modify the working electrode surface of different screen-printed carbon electrodes (SPCE) with the aim of improving the sensitivity of the SPCE and comparing it with the conventional glassy carbon electrode. To assay the usability of these sensors, a HPLC methodology with amperometric detection was developed to analyze several phytochelatins in plants of Hordeum vulgare and Glycine max treated with Hg(II) or Cd(II) giving detection limits in the low μmolL(-1) range. Phytochelatins are low molecular weight peptides with the general structure γ-(Glu-Cys)n-Gly (n=2-5) which are synthesized in plants in the presence of heavy metal ions. These compounds can chelate heavy metal ions by the formation of complexes which, are transported to the vacuoles, where the toxicity is not threatening. For this reason phytochelatins are essential in the detoxification of heavy metal ions in plants. The developed HPLC method uses a mobile phase of 1% of formic acid in water with KNO3 or NaCl (pH=2.00) and 1% of formic acid in acetonitrile. Electrochemical detection at different carbon-based electrodes was used. Among the sensors tested, the conventional glassy carbon electrode offers the best sensitivity although modification improves the sensitivity of the SPCE. Glutathione and several isoforms of phytochelatin two were found in plant extracts of both studied species. Copyright © 2015 Elsevier B.V. All rights reserved.

Chloride-dependency of amyloid beta protein-induced enhancement of glutamate neurotoxicity in cultured rat hippocampal neurons.

PubMed

Zhang, Nan-Yan; Kitagawa, Kaori; Wu, Bo; Xiong, Zheng-Mei; Otani, Hitomi; Inagaki, Chiyoko

2006-05-15

In our previous studies, pathophysiological concentrations of amyloid-beta (Abeta) proteins increased intracellular Cl(-) concentration ([Cl(-)]i) and enhanced glutamate neurotoxicity in primary cultured neurons, suggesting Cl(-)-dependent changes in glutamate signaling. To test this possibility, we examined the effects of isethionate-replaced low Cl(-) medium on the Abeta-induced enhancement of glutamate neurotoxicity in the primary cultured rat hippocampal neurons. In a normal Cl(-) (135 mM) medium, treatment with 10 nM Abeta25-35 for 2 days increased neuronal [Cl(-)]i to a level three times higher than that of control as assayed using a Cl(-)-sensitive fluorescent dye, while in a low Cl(-) (16 mM) medium such an Abeta25-35-induced increase in [Cl(-)]i was not observed. The Abeta treatment aggravated glutamate neurotoxicity in a normal Cl(-) medium as measured by mitochondrial reducing activity and lactate dehydrogenase (LDH) release, while in a low Cl(-) medium the Abeta treatment did not enhance glutamate toxicity. Upon such Abeta plus glutamate treatment under a normal Cl(-) condition, activated anti-apoptotic molecule Akt (Akt-pS473) level monitored by Western blot significantly decreased to 74% of control. Under a low Cl(-) condition, a resting Akt-pS473 level was higher than that under a normal Cl(-) condition and did not significantly change upon Abeta plus glutamate treatment. Tyrosine phosphorylation levels of 110 and 60 kDa proteins (pp110 and pp60) increased upon Abeta plus glutamate treatment under a normal Cl(-), but not low Cl(-), condition. These findings indicated that Abeta-induced enhancement of glutamate neurotoxicity is Cl(-)-dependent. Chloride-sensitive Akt pathway and tyrosine phosphorylation of proteins (pp110 and pp60) may be involved in this process.

A high-throughput method to measure NaCl and acid taste thresholds in mice.

PubMed

Ishiwatari, Yutaka; Bachmanov, Alexander A

2009-05-01

To develop a technique suitable for measuring NaCl taste thresholds in genetic studies, we conducted a series of experiments with outbred CD-1 mice using conditioned taste aversion (CTA) and two-bottle preference tests. In Experiment 1, we compared conditioning procedures involving either oral self-administration of LiCl or pairing NaCl intake with LiCl injections and found that thresholds were the lowest after LiCl self-administration. In Experiment 2, we compared different procedures (30-min and 48-h tests) for testing conditioned mice and found that the 48-h test is more sensitive. In Experiment 3, we examined the effects of varying strength of conditioned (NaCl or LiCl taste intensity) and unconditioned (LiCl toxicity) stimuli and concluded that 75-150 mM LiCl or its mixtures with NaCl are the optimal stimuli for conditioning by oral self-administration. In Experiment 4, we examined whether this technique is applicable for measuring taste thresholds for other taste stimuli. Results of these experiments show that conditioning by oral self-administration of LiCl solutions or its mixtures with other taste stimuli followed by 48-h two-bottle tests of concentration series of a conditioned stimulus is an efficient and sensitive method to measure taste thresholds. Thresholds measured with this technique were 2 mM for NaCl and 1 mM for citric acid. This approach is suitable for simultaneous testing of large numbers of animals, which is required for genetic studies. These data demonstrate that mice, like several other species, generalize CTA from LiCl to NaCl, suggesting that they perceive taste of NaCl and LiCl as qualitatively similar, and they also can generalize CTA of a binary mixture of taste stimuli to mixture components.

Cl atom recombination on silicon oxy-chloride layers deposited on chamber walls in chlorine-oxygen plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khare, Rohit; Srivastava, Ashutosh; Donnelly, Vincent M.

2012-09-15

Chlorine atom recombination coefficients were measured on silicon oxy-chloride surfaces deposited in a chlorine inductively coupled plasma (ICP) with varying oxygen concentrations, using the spinning wall technique. A small cylinder embedded in the walls of the plasma reactor chamber was rapidly rotated, repetitively exposing its surface to the plasma chamber and a differentially pumped analysis chamber housing a quadruple mass spectrometer for line-of-sight desorbing species detection, or an Auger electron spectrometer for in situ surface analysis. The spinning wall frequency was varied from 800 to 30 000 rpm resulting in a detection time, t (the time a point on themore » surface takes to rotate from plasma chamber to the position facing the mass or Auger spectrometer), of {approx}1-40 ms. Desorbing Cl{sub 2}, due to Langmuir-Hinshelwood (LH) Cl atom recombination on the reactor wall surfaces, was detected by the mass spectrometer and also by a pressure rise in one of the differentially pumped chambers. LH Cl recombination coefficients were calculated by extrapolating time-resolved desorption decay curves to t = 0. A silicon-covered electrode immersed in the plasma was either powered at 13 MHz, creating a dc bias of -119 V, or allowed to electrically float with no bias power. After long exposure to a Cl{sub 2} ICP without substrate bias, slow etching of the Si wafer coats the chamber and spinning wall surfaces with an Si-chloride layer with a relatively small amount of oxygen (due to a slow erosion of the quartz discharge tube) with a stoichiometry of Si:O:Cl = 1:0.38:0.38. On this low-oxygen-coverage surface, any Cl{sub 2} desorption after LH recombination of Cl was below the detection limit. Adding 5% O{sub 2} to the Cl{sub 2} feed gas stopped etching of the Si wafer (with no rf bias) and increased the oxygen content of the wall deposits, while decreasing the Cl content (Si:O:Cl = 1:1.09:0.08). Cl{sub 2} desorption was detectable for Cl recombination on the spinning wall surface coated with this layer, and a recombination probability of {gamma}{sub Cl} = 0.03 was obtained. After this surface was conditioned with a pure oxygen plasma for {approx}60 min, {gamma}{sub Cl} increased to 0.044 and the surface layer was slightly enriched in oxygen fraction (Si:O:Cl = 1:1.09:0.04). This behavior is attributed to a mechanism whereby Cl LH recombination occurs mainly on chlorinated oxygen sites on the silicon oxy-chloride surface, because of the weak Cl-O bond compared to the Cl-Si bond.« less

Oral Progestin Priming Increases Ovarian Sensitivity to Gonadotropin Stimulation and Improves Luteal Function in the Cat1

PubMed Central

Stewart, Rosemary A.; Pelican, Katharine M.; Crosier, Adrienne E.; Pukazhenthi, Budhan S.; Wildt, David E.; Ottinger, Mary Ann; Howard, JoGayle

2012-01-01

ABSTRACT As the only domesticated species known to exhibit both induced and spontaneous ovulation, the cat is a model for understanding the nuances of ovarian control. To explore ovarian sensitivity to exogenous gonadotropins and the influence of progestin priming, we conducted a study of queens that were down-regulated with oral progestin or allowed to cycle normally, followed by low or high doses of equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG). Our metrics included 1) fecal steroid metabolite profiles before and after ovulation induction, 2) laparoscopic examination of ovarian follicles and corpora lutea (CL) on Days 2 and 17 (Day 0 = hCG administration), and 3) ovariohysterectomy (Day 17) to assess CL progesterone concentrations, morphometrics, and histology. Reproductive tracts from time-matched, naturally mated queens (n = 6) served as controls. Every progestin-primed cat (n = 12) produced the desired response of morphologically similar, fresh CL (regardless of eCG/hCG dose) by Day 2, whereas 41.7% of unprimed counterparts (n = 12) failed to ovulate or had variable-aged CL suggestive of prior spontaneous ovulation (P < 0.05). The ovarian response to low, but not high, eCG/hCG was improved (P < 0.05) in primed compared to unprimed cats, indicating increased sensitivity to gonadotropin in the progestin-primed ovary. Progestin priming prevented hyperelevated fecal steroid metabolites and normalized CL progesterone capacity, but only when combined with low eCG/hCG. However, priming failed to prevent ancillary CL formation, smaller CL mass, or abnormal luteal cell density, which were common to all eCG/hCG-treated cats. Thus, the domestic cat exposed to eCG/hCG produces CL with structural and functional aberrations. These anomalies can be partially mitigated by progestin priming, possibly due to a protective effect of progestin associated with enhanced ovarian sensitivity to gonadotropins. PMID:23100619

Electrophoresis-chemiluminescence detection of phenols catalyzed by hemin.

PubMed

Shu, Lu; Zhu, Jinkun; Wang, Qingjiang; He, Pingang; Fang, Yuzhi

2014-09-01

Based on the catalytic activity of hemin, an efficient biocatalyst, an indirect capillary electrophoresis-chemiluminescence (CE-CL) detection method for phenols using a hemin-luminol-hydrogen peroxide system was developed. Through a series of static injection experiments, hemin was found to perform best in a neutral solution rather than an acidic or alkaline medium. Although halide ions such as Br(-) and F(-) could further enhance the CL signal catalyzed by hemin, it is difficult to apply these conditions to this CE-CL detection system because of the self-polymerization of hemin, as it hinders the CE process. The addition of concentrated ammonium hydroxide to an aqueous/dimethyl sulfoxide solution of hemin-luminol afforded a stable CE-CL baseline. The indirect CE-CL detection of five phenols using this method gave the following limits of detections: 4.8 × 10(-8) mol/L (o-sec-butylphenol), 4.9 × 10(-8) mol/L (o-cresol), 5.4 × 10(-8) mol/L (m-cresol), 5.3 × 10(-8) mol/L (2,4-dichlorophenol) and 7.1 × 10(-8) mol/L (phenol). Copyright © 2013 John Wiley & Sons, Ltd.

Signal transduction mechanisms of K+-Cl- cotransport regulation and relationship to disease.

PubMed

Adragna, N C; Ferrell, C M; Zhang, J; Di Fulvio, M; Temprana, C F; Sharma, A; Fyffe, R E W; Cool, D R; Lauf, P K

2006-01-01

The K+-Cl- cotransport (COT) regulatory pathways recently uncovered in our laboratory and their implication in disease state are reviewed. Three mechanisms of K+-Cl- COT regulation can be identified in vascular cells: (1) the Li+-sensitive pathway, (2) the platelet-derived growth factor (PDGF)-sensitive pathway and (3) the nitric oxide (NO)-dependent pathway. Ion fluxes, Western blotting, semi-quantitative RT-PCR, immunofluorescence and confocal microscopy were used. Li+, used in the treatment of manic depression, stimulates volume-sensitive K+-Cl- COT of low K+ sheep red blood cells at cellular concentrations <1 mM and inhibits at >3 mM, causes cell swelling, and appears to regulate K+-Cl- COT through a protein kinase C-dependent pathway. PDGF, a potent serum mitogen for vascular smooth muscle cells (VSMCs), regulates membrane transport and is involved in atherosclerosis. PDGF stimulates VSM K+-Cl- COT in a time- and concentration-dependent manner, both acutely and chronically, through the PDGF receptor. The acute effect occurs at the post-translational level whereas the chronic effect may involve regulation through gene expression. Regulation by PDGF involves the signalling molecules phosphoinositides 3-kinase and protein phosphatase-1. Finally, the NO/cGMP/protein kinase G pathway, involved in vasodilation and hence cardiovascular disease, regulates K+-Cl- COT in VSMCs at the mRNA expression and transport levels. A complex and diverse array of mechanisms and effectors regulate K+-Cl- COT and thus cell volume homeostasis, setting the stage for abnormalities at the genetic and/or regulatory level thus effecting or being affected by various pathological conditions.

Dynamic potential and surface morphology study of sertraline membrane sensors

PubMed Central

Khater, M.M.; Issa, Y.M.; Hassib, H.B.; Mohammed, S.H.

2014-01-01

New rapid, sensitive and simple electrometric method was developed to determine sertraline hydrochloride (Ser-Cl) in its pure raw material and pharmaceutical formulations. Membrane sensors based on heteropolyacids as ion associating material were prepared. Silicomolybdic acid (SMA), silicotungstic acid (STA) and phosphomolybdic acid (PMA) were used. The slope and limit of detection are 50.00, 60.00 and 53.24 mV/decade and 2.51, 5.62 and 4.85 μmol L−1 for Ser-ST, Ser-PM and Ser-SM membrane sensors, respectively. Linear range is 0.01–10.00 for the three sensors. These new sensors were used for the potentiometric titration of Ser-Cl using sodium tetraphenylborate as titrant. The surface morphologies of the prepared membranes with and without the modifier (ion-associate) were studied using scanning and atomic force microscopes. PMID:26257944

Environmental applications for the analysis of chlorinated dibenzo-p-dioxins and dibenzofurans using mass spectrometry/mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reiner, E.J.; Schellenberg, D.H.; Taguchi, V.Y.

1991-01-01

A mass spectrometry/mass spectrometry-multiple reaction monitoring (MS/MS-MRM) technique for the analysis of all tetra- through octachlorinated dibenzo-p-dioxins (Cl{sub x}DD, x = 4-8) and dibenzofurans (Cl{sub x}DF, x = 4-8) has been developed at the Ministry of the Environment (MOE) utilizing a triple quadrupole mass spectrometer. Optimization of instrumental parameters using the analyte of interest in a direct insertion probe (DIP) resulted in sensitivities approaching those obtainable by high-resolution mass spectrometric (HRMS) methods. All congeners of dioxins and furans were detected in the femtogram range. Results on selected samples indicated that for some matrices, fewer chemical interferences were observed by MS/MSmore » than by HRMS. The technique used to optimize the instrument for chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs) analysis is adaptable to other analytes.« less

Directional Limits on Persistent Gravitational Waves Using LIGO S5 Science Data

NASA Astrophysics Data System (ADS)

Abadie, J.; Abbott, B. P.; Abbott, R.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Ajith, P.; Allen, B.; Allen, G. S.; Amador Ceron, E.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Antonucci, F.; Arain, M. A.; Araya, M. C.; Aronsson, M.; Arun, K. G.; Aso, Y.; Aston, S. M.; Astone, P.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Babak, S.; Baker, P.; Ballardin, G.; Ballmer, S.; Barker, D.; Barnum, S.; Barone, F.; Barr, B.; Barriga, P.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Bauchrowitz, J.; Bauer, Th. S.; Behnke, B.; Beker, M. G.; Belletoile, A.; Benacquista, M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bigotta, S.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birindelli, S.; Biswas, R.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Blom, M.; Boccara, C.; Bock, O.; Bodiya, T. P.; Bondarescu, R.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Bose, S.; Bosi, L.; Bouhou, B.; Boyle, M.; Braccini, S.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Breyer, J.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Budzyński, R.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burguet-Castell, J.; Burmeister, O.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cain, J.; Calloni, E.; Camp, J. B.; Campagna, E.; Campsie, P.; Cannizzo, J.; Cannon, K.; Canuel, B.; Cao, J.; Capano, C.; Carbognani, F.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chalermsongsak, T.; Chalkley, E.; Charlton, P.; Chassande-Mottin, E.; Chelkowski, S.; Chen, Y.; Chincarini, A.; Christensen, N.; Chua, S. S. Y.; Chung, C. T. Y.; Clark, D.; Clark, J.; Clayton, J. H.; Cleva, F.; Coccia, E.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, R.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coulon, J.-P.; Coward, D. M.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Culter, R. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; D'Antonio, S.; Danzmann, K.; Das, K.; Dattilo, V.; Daudert, B.; Davier, M.; Davies, G.; Davis, A.; Daw, E. J.; Day, R.; Dayanga, T.; de Rosa, R.; Debra, D.; Degallaix, J.; Del Prete, M.; Dergachev, V.; Derosa, R.; Desalvo, R.; Devanka, P.; Dhurandhar, S.; di Fiore, L.; di Lieto, A.; di Palma, I.; di Paolo Emilio, M.; di Virgilio, A.; Díaz, M.; Dietz, A.; Donovan, F.; Dooley, K. L.; Doomes, E. E.; Dorsher, S.; Douglas, E. S. D.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Dueck, J.; Dumas, J.-C.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Engel, R.; Etzel, T.; Evans, M.; Evans, T.; Fafone, V.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Ferrante, I.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Flaminio, R.; Flanigan, M.; Flasch, K.; Foley, S.; Forrest, C.; Forsi, E.; Fotopoulos, N.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Galimberti, M.; Gammaitoni, L.; Garofoli, J. A.; Garufi, F.; Gemme, G.; Genin, E.; Gennai, A.; Gholami, I.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gill, C.; Goetz, E.; Goggin, L. M.; González, G.; Gorodetsky, M. L.; Goßler, S.; Gouaty, R.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Greverie, C.; Grosso, R.; Grote, H.; Grunewald, S.; Guidi, G. M.; Gustafson, E. K.; Gustafson, R.; Hage, B.; Hall, P.; Hallam, J. M.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Haughian, K.; Hayama, K.; Hayau, J.-F.; Hayler, T.; Heefner, J.; Heitmann, H.; Hello, P.; Heng, I. S.; Heptonstall, A. W.; Hewitson, M.; Hild, S.; Hirose, E.; Hoak, D.; Hodge, K. A.; Holt, K.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hoyland, D.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh–Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Jaranowski, P.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kanner, J. B.; Katsavounidis, E.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kells, W.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, H.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kondrashov, V.; Kopparapu, R.; Koranda, S.; Kowalska, I.; Kozak, D.; Krause, T.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Królak, A.; Kuehn, G.; Kullman, J.; Kumar, R.; Kwee, P.; Landry, M.; Lang, M.; Lantz, B.; Lastzka, N.; Lazzarini, A.; Leaci, P.; Leong, J.; Leonor, I.; Leroy, N.; Letendre, N.; Li, J.; Li, T. G. F.; Liguori, N.; Lin, H.; Lindquist, P. E.; Lockerbie, N. A.; Lodhia, D.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lu, P.; Luan, J.; Lubinski, M.; Lucianetti, A.; Lück, H.; Lundgren, A. D.; Machenschalk, B.; Macinnis, M.; Mageswaran, M.; Mailand, K.; Majorana, E.; Mak, C.; Maksimovic, I.; Man, N.; Mandel, I.; Mandic, V.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Masserot, A.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIvor, G.; McKechan, D. J. A.; Meadors, G.; Mehmet, M.; Meier, T.; Melatos, A.; Melissinos, A. C.; Mendell, G.; Menéndez, D. F.; Mercer, R. A.; Merill, L.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Michel, C.; Milano, L.; Miller, J.; Minenkov, Y.; Mino, Y.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Mohan, M.; Mohanty, S. D.; Mohapatra, S. R. P.; Moraru, D.; Moreau, J.; Moreno, G.; Morgado, N.; Morgia, A.; Morioka, T.; Mors, K.; Mosca, S.; Moscatelli, V.; Mossavi, K.; Mours, B.; Mow–Lowry, C. M.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Müller-Ebhardt, H.; Munch, J.; Murray, P. G.; Nash, T.; Nawrodt, R.; Nelson, J.; Neri, I.; Newton, G.; Nishizawa, A.; Nocera, F.; Nolting, D.; Ochsner, E.; O'Dell, J.; Ogin, G. H.; Oldenburg, R. G.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Page, A.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Pardi, S.; Pareja, M.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patel, P.; Pathak, D.; Pedraza, M.; Pekowsky, L.; Penn, S.; Peralta, C.; Perreca, A.; Persichetti, G.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Plissi, M. V.; Poggiani, R.; Postiglione, F.; Prato, M.; Predoi, V.; Price, L. R.; Prijatelj, M.; Principe, M.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Quetschke, V.; Raab, F. J.; Rabeling, D. S.; Radke, T.; Radkins, H.; Raffai, P.; Rakhmanov, M.; Rankins, B.; Rapagnani, P.; Raymond, V.; Re, V.; Reed, C. M.; Reed, T.; Regimbau, T.; Reid, S.; Reitze, D. H.; Ricci, F.; Riesen, R.; Riles, K.; Roberts, P.; Robertson, N. A.; Robinet, F.; Robinson, C.; Robinson, E. L.; Rocchi, A.; Roddy, S.; Röver, C.; Rolland, L.; Rollins, J.; Romano, J. D.; Romano, R.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sakata, S.; Sakosky, M.; Salemi, F.; Sammut, L.; Sancho de La Jordana, L.; Sandberg, V.; Sannibale, V.; Santamaría, L.; Santostasi, G.; Saraf, S.; Sassolas, B.; Sathyaprakash, B. S.; Sato, S.; Satterthwaite, M.; Saulson, P. R.; Savage, R.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Searle, A. C.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sergeev, A.; Shaddock, D. A.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sibley, A.; Siemens, X.; Sigg, D.; Singer, A.; Sintes, A. M.; Skelton, G.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, N. D.; Somiya, K.; Sorazu, B.; Speirits, F. C.; Sperandio, L.; Stein, A. J.; Stein, L. C.; Steinlechner, S.; Steplewski, S.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S.; Stroeer, A. S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sung, M.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Szokoly, G. P.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, J. R.; Taylor, R.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Thüring, A.; Titsler, C.; Tokmakov, K. V.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C.; Torrie, C. I.; Tournefier, E.; Travasso, F.; Traylor, G.; Trias, M.; Trummer, J.; Tseng, K.; Turner, L.; Ugolini, D.; Urbanek, K.; Vahlbruch, H.; Vaishnav, B.; Vajente, G.; Vallisneri, M.; van den Brand, J. F. J.; van den Broeck, C.; van der Putten, S.; van der Sluys, M. V.; van Veggel, A. A.; Vass, S.; Vaulin, R.; Vavoulidis, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Veltkamp, C.; Verkindt, D.; Vetrano, F.; Viceré, A.; Villar, A. E.; Vinet, J.-Y.; Vocca, H.; Vorvick, C.; Vyachanin, S. P.; Waldman, S. J.; Wallace, L.; Wanner, A.; Ward, R. L.; Was, M.; Wei, P.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wen, S.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D.; Whiting, B. F.; Wilkinson, C.; Willems, P. A.; Williams, L.; Willke, B.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Woan, G.; Wooley, R.; Worden, J.; Yakushin, I.; Yamamoto, H.; Yamamoto, K.; Yeaton-Massey, D.; Yoshida, S.; Yu, P.; Yvert, M.; Zanolin, M.; Zhang, L.; Zhang, Z.; Zhao, C.; Zotov, N.; Zucker, M. E.; Zweizig, J.

2011-12-01

The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2-20×10-50strain2Hz-1 and 5-35×10-49strain2Hz-1sr-1 for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets including Sco X-1, SN 1987A and the Galactic center as low as ≈7×10-25 in the most sensitive frequency range near 160 Hz.

3D-Printed Graphene/Polylactic Acid Electrodes Promise High Sensitivity in Electroanalysis.

PubMed

Manzanares Palenzuela, C Lorena; Novotný, Filip; Krupička, Petr; Sofer, Zdeněk; Pumera, Martin

2018-05-01

Additive manufacturing provides a unique tool for prototyping structures toward electrochemical sensing, due to its ability to produce highly versatile, tailored-shaped devices in a low-cost and fast way with minimized waste. Here we present 3D-printed graphene electrodes for electrochemical sensing. Ring- and disc-shaped electrodes were 3D-printed with a Fused Deposition Modeling printer and characterized using cyclic voltammetry and scanning electron microscopy. Different redox probes K 3 Fe(CN) 6 :K 4 Fe(CN) 6 , FeCl 3 , ascorbic acid, Ru(NH 3 ) 6 Cl 3 , and ferrocene monocarboxylic acid) were used to assess the electrochemical performance of these devices. Finally, the electrochemical detection of picric acid and ascorbic acid was carried out as proof-of-concept analytes for sensing applications. Such customizable platforms represent promising alternatives to conventional electrodes for a wide range of sensing applications.

Limits on low-energy neutrino fluxes with the Mont Blanc liquid scintillator detector

NASA Astrophysics Data System (ADS)

Aglietta, M.; Antonioli, P.; Badino, G.; Bologna, G.; Castagnoli, C.; Castellina, A.; Dadykin, V. L.; Fulgione, W.; Galeotti, P.; Khalchukov, F. F.; Korolkova, E. V.; Kortchaguin, P. V.; Kortchaguin, V. B.; Kudryavtsev, V. A.; Malguin, A. S.; Periale, L.; Ryassny, V. G.; Ryazhskaya, O. G.; Saavedra, O.; Trinchero, G.; Vernetto, S.; Yakushev, V. F.; Zatsepin, G. T.

1992-11-01

The LSD liquid scintillation detector has been operating since 1985 as an underground neutrino observatory in the Mont Blanc Laboratory with the main objective of detecting antineutrino bursts from collapsing stars. In August 1988 the construction of an additional lead and borex paraffin shield considerably reduced the radioactive background and increased the sensitivity of the apparatus. In this way the search for steady fluxes of low-energy neutrinos of different flavours through their interactions with free protons and carbon nuclei of the scintillator was made possible. No evidence for a galactic collapse was observed during the whole period of measurement. The corresponding 90% c.l. upper limit on the galactic collapses rate is 0.45 y -1 for a burst duration of ΔT ⩽ 10 s. After analysing the last 3 years data, the following 90% c.l. upper limits on the steady neutrino and antineutrino fluxes were obtained:

Development of chitosan-coated gold nanoflowers as SERS-active probes

NASA Astrophysics Data System (ADS)

Xu, Dan; Gu, Jiangjiang; Wang, Weina; Yu, Xuehai; Xi, Kai; Jia, Xudong

2010-09-01

Surface-enhanced Raman scattering (SERS) has been intensely researched for many years as a potential technique for highly sensitive detection. This work, through the reduction of HAuCl4 with pyrrole in aqueous solutions, investigated a facile one-pot synthesis of flower-like Au nanoparticles with rough surfaces. The formation process of the Au nanoflowers (AuNFs) was carefully studied, and a spontaneous assembly mechanism was proposed based on the time-course experimental results. The key synthesis strategy was to use pyrrole as a weak particle stabilizing and reducing agent to confine crystal growth in the limited ligand protection region. The nanometer-scale surface roughness of AuNFs provided several hot spots on a single particle, which significantly increased SERS enhancement. Good biocompatible stable Raman-active probes were synthesized by coating AuNFs with chitosan. The conservation of the SERS effects in living cells suggested that the chitosan-capped AuNFs could be suitable for highly sensitive detection and have potential for targeting of tumors in vivo.

Investigation of Sensitivities and Drift Effects of the Arrayed Flexible Chloride Sensor Based on RuO₂/GO at Different Temperatures.

PubMed

Tseng, Shi-Chang; Wu, Tong-Yu; Chou, Jung-Chuan; Liao, Yi-Hung; Lai, Chih-Hsien; Yan, Siao-Jie; Tseng, Ting-Wei

2018-02-20

We investigate the temperature effect on sensing characteristics and drift effect of an arrayed flexible ruthenium dioxide (RuO₂)/graphene oxide (GO) chloride sensor at different solution temperatures between 10 °C and 50 °C. The average sensor sensitivities according to our experimental results were 28.2 ± 1.4 mV/pCl (10 °C), 42.5 ± 2.0 mV/pCl (20 °C), 47.1 ± 1.8 mV/pCl (30 °C), 54.1 ± 2.01 mV/pCl (40 °C) and 46.6 ± 2.1 mV/pCl (50 °C). We found the drift effects of an arrayed flexible RuO₂/GO chloride sensor in a 1 M NaCl solution to be between 8.2 mV/h and 2.5 mV/h with solution temperatures from 10 °C to 50 °C.

Investigation of Sensitivities and Drift Effects of the Arrayed Flexible Chloride Sensor Based on RuO2/GO at Different Temperatures

PubMed Central

Tseng, Shi-Chang; Wu, Tong-Yu; Liao, Yi-Hung; Lai, Chih-Hsien; Yan, Siao-Jie; Tseng, Ting-Wei

2018-01-01

We investigate the temperature effect on sensing characteristics and drift effect of an arrayed flexible ruthenium dioxide (RuO2)/graphene oxide (GO) chloride sensor at different solution temperatures between 10 °C and 50 °C. The average sensor sensitivities according to our experimental results were 28.2 ± 1.4 mV/pCl (10 °C), 42.5 ± 2.0 mV/pCl (20 °C), 47.1 ± 1.8 mV/pCl (30 °C), 54.1 ± 2.01 mV/pCl (40 °C) and 46.6 ± 2.1 mV/pCl (50 °C). We found the drift effects of an arrayed flexible RuO2/GO chloride sensor in a 1 M NaCl solution to be between 8.2 mV/h and 2.5 mV/h with solution temperatures from 10 °C to 50 °C. PMID:29461506

Cytotoxicity and genotoxicity of polyethylenimine and nickel chloride in red sea bream ( Pagrosomus major) fin cell line RSBF

NASA Astrophysics Data System (ADS)

Guo, Hua-Rong; Zhang, Shi-Cui

2002-12-01

A continuous marine fish cell line RSBF (i. c. Red Sea Bream Fin) was utilized to screen the cytotoxicity and genotoxicity of polyethylenimine (PEI) and nickel chloride (NiCl2) in this study on the deleterious effects of aquatic genotoxins on fish. At the 0.01 to 1 μg/ml concentration tested, PEI had acute toxicity to the treated RSBF cells (IC50=1.12, 0.92, 0.88 and 0.64 μg/ml PEI for time 0 h, 24 h, 48 h and 72 h after treatment, respectively) and markedly inhibited their proliferation in a dose-dependent manner. At the 0.001 to 5 μmol/L concentration tested, NiCl2 posed no acute toxicity but significantly stimulated their growth (107% 214% of control). Random amplified polymorphic DNA (RAPD) technique was used to detect the genotoxic effects of PEI and NiCl2 by comparing the RAPD banding patterns of the control and treated cells. RAPD analysis indicated that at the concentrations tested, PEI was more genotoxic than NiCl2 to RSBF cells; that there was a slight dose-dependent response in the genotoxic effect of PEI but not NiCl2; and that RAPD technique might provide a sensitive, non-specific genotoxic endpoint. And the potent cytotoxicity and genotoxicity of PEI on fish cells showed that we should be cautious in utilizing it as gene, vector in fish gene transfer and human gene therapy.

Development and evaluation of a novel LAMP assay for the diagnosis of Cutaneous and Visceral Leishmaniasis.

PubMed

Adams, Emily Rebecca; Schoone, Gerard; Versteeg, Inge; Gomez, Maria Adelaida; Diro, Ermias; Mori, Yasuyoshi; Perlee, Desiree; Downing, Tim; Saravia, Nancy; Assaye, Ashenafi; Hailu, Asrat; Albertini, Audrey; Ndung'u, Joseph Mathu; Schallig, Henk

2018-04-25

A novel Pan-Leishmania LAMP assay was developed for diagnosis of Cutaneous and Visceral Leishmaniasis (CL & VL) which can be used in near-patient settings. Primers were designed on the 18S rDNA and the conserved region of minicircle kDNA selected on the basis of high copy number. LAMP assays were evaluated for CL in a prospective cohort trial of 105 patients in South-West Colombia. Lesion swab samples from CL suspects were collected and tested using LAMP and compared to a composite reference of microscopy AND/OR culture to calculate diagnostic accuracy. LAMP assays were tested on 50 VL suspected patients from Ethiopia, including whole blood, peripheral blood mononuclear cells, and buffy coat. Diagnostic accuracy was calculated against a reference standard of microscopy of splenic or bone marrow aspirates. To calculate analytical specificity 100 clinical samples and isolates with fever causing pathogens including malaria, arboviruses and bacterial infections were tested. The LAMP assay had a sensitivity of 95% (95% CI: 87.2% - 98.5 %) and a specificity of 86% (95% CI: 67.3% -95.9 %) for the diagnosis of CL. On VL suspects the sensitivity was 92% (95% CI: 74.9 - 99.1%) and specificity of 100% (95% CI: 85.8-100%) in whole blood. For CL, LAMP is a sensitive tool for diagnosis and requires less equipment, time and expertise than alternative CL diagnostics. For VL, LAMP is sensitive using a minimally invasive sample as compared to the gold standard. The analytical specificity was 100%. Copyright © 2018 Adams et al.

Evaluation of the efficacy of a portable LIBS system for detection of CWA on surfaces.

PubMed

L'Hermite, D; Vors, E; Vercouter, T; Moutiers, G

2016-05-01

Laser-induced breakdown spectroscopy (LIBS) is a laser-based optical technique particularly suited for in situ surface analysis. A portable LIBS instrument was tested to detect surface chemical contamination by chemical warfare agents (CWAs). Test of detection of surface contamination was carried out in a toxlab facility with four CWAs, sarin (GB), lewisite (L1), mustard gas (HD), and VX, which were deposited on different substrates, wood, concrete, military green paint, gloves, and ceramic. The CWAs were detected by means of the detection of atomic markers (As, P, F, Cl, and S). The LIBS instrument can give a direct response in terms of detection thanks to an integrated interface for non-expert users or so called end-users. We have evaluated the capability of automatic detection of the selected CWAs. The sensitivity of our portable LIBS instrument was confirmed for the detection of a CWA at surface concentrations above 15 μg/cm(2). The simultaneous detection of two markers may lead to a decrease of the number of false positive.

Regulation of intracellular pH in the rabbit cortical collecting tubule.

PubMed Central

Weiner, I D; Hamm, L L

1990-01-01

The cortical collecting tubule (CCT) is an important nephron segment for Na+, K+, water and acid-base transport. Differential loading characteristics of the pH sensitive dye 2',7'-bis-(2-carboxyethyl)-5(and-6)carboxyfluorescein (BCECF) and basolateral Cl- removal were used to identify and study intracellular pH (pHi) regulation in each of three cell types involved in this transport. Both principal cells and beta-intercalated cells were found to have a basolateral Na+/H+ exchanger based on the Na+ and amiloride sensitivity of pHi recovery from acid loads. Intercalated cells demonstrated abrupt pHi changes with basolateral Cl- removal. alpha-intercalated cells alkalinized; beta-intercalated cells acidified. In the beta-intercalated cells, luminal Cl- removal blocked changes in pHi in response to changes in luminal HCO3- or peritubular Cl-, providing direct evidence for a luminal Cl-/HCO3- exchanger. In principal cells, brief removal of either peritubular or luminal Cl- resulted in no change in pHi; however, return of peritubular Cl- after prolonged removal resulted in a rapid fall in pHi consistent with a basolateral Cl-/HCO3- exchanger, which may be relatively inactive under baseline conditions. Therefore, Cl-/HCO3- exchange is present in all three cell types but varies in location and activity. PMID:2153152

Easy one pot synthesis of NiO/Nitrogen doped carbon spheres for highly sensitive enzyme free amperometric glucose sensors

NASA Astrophysics Data System (ADS)

Zhu, Jiajie; Yin, Haoyong; Gong, Jianying; Al-Furjan, M. S. H.; Nie, Qiulin

2018-06-01

The NiO/Nitrogen doped carbon sphere (NiO/NCS) composites were successfully achieved via an easy one pot synthetic method with urea acting as both nitrogen source and Ni precipitator. The electrocatalytic performances of the obtained NiO/NCS modified glass carbon electrodes showed superior activity for direct electrocatalytic oxidation of glucose than that of nitrogen free NiO/carbon sphere (NiO/CS), which might be due to the synergistic effect of the properties of NCS and NiO nanoparticles. The introduce of nitrogen can improve the conductivity of the NiO/NCS and accordingly accelerate the electron transport within the composites, which was very beneficial to improve the sensitivity to glucose detection for NiO/NCS modified electrodes. The NiO/NCS electrodes exhibited two corresponding linear regions of 1-800 μM and 4-9 mM with the sensitivity of 398.57 μA mM-1 cm-2 and 17.81 μA mM-1 cm-2, and the detection limit of 0.25 μM and 0.05 mM respectively. Moreover, the NiO/NCS composites have also exhibited good selectivity by adding certain amount of urea, NaCl, L-proline, L-valine, L-Leucine and ascorbic acid into the 0.1 M NaOH solution, respectively. The high sensitivity, wide glucose detection range and good selectivity of the electrodes may ensure its potential applications in the clinical diagnosis of diabetes.

Chemiresistive Graphene Sensors for Ammonia Detection.

PubMed

Mackin, Charles; Schroeder, Vera; Zurutuza, Amaia; Su, Cong; Kong, Jing; Swager, Timothy M; Palacios, Tomás

2018-05-09

The primary objective of this work is to demonstrate a novel sensor system as a convenient vehicle for scaled-up repeatability and the kinetic analysis of a pixelated testbed. This work presents a sensor system capable of measuring hundreds of functionalized graphene sensors in a rapid and convenient fashion. The sensor system makes use of a novel array architecture requiring only one sensor per pixel and no selector transistor. The sensor system is employed specifically for the evaluation of Co(tpfpp)ClO 4 functionalization of graphene sensors for the detection of ammonia as an extension of previous work. Co(tpfpp)ClO 4 treated graphene sensors were found to provide 4-fold increased ammonia sensitivity over pristine graphene sensors. Sensors were also found to exhibit excellent selectivity over interfering compounds such as water and common organic solvents. The ability to monitor a large sensor array with 160 pixels provides insights into performance variations and reproducibility-critical factors in the development of practical sensor systems. All sensors exhibit the same linearly related responses with variations in response exhibiting Gaussian distributions, a key finding for variation modeling and quality engineering purposes. The mean correlation coefficient between sensor responses was found to be 0.999 indicating highly consistent sensor responses and excellent reproducibility of Co(tpfpp)ClO 4 functionalization. A detailed kinetic model is developed to describe sensor response profiles. The model consists of two adsorption mechanisms-one reversible and one irreversible-and is shown capable of fitting experimental data with a mean percent error of 0.01%.

Effect of sodium chloride concentration on elemental analysis of brines by laser-induced breakdown spectroscopy (LIBS).

PubMed

Goueguel, Christian; Singh, Jagdish P; McIntyre, Dustin L; Jain, Jinesh; Karamalidis, Athanasios K

2014-01-01

Leakage of injected carbon dioxide (CO2) or resident fluids, such as brine, is a major concern associated with the injection of large volumes of CO2 into deep saline formations. Migration of brine could contaminate drinking water resources by increasing their salinity or endanger vegetation and animal life as well as human health. The main objective of this study was to investigate the effect of sodium chloride (NaCl) concentration on the detection of calcium and potassium in brine samples using laser-induced breakdown spectroscopy (LIBS). The ultimate goals were to determine the suitability of the LIBS technique for in situ measurements of metal ion concentrations in NaCl-rich solution and to develop a chemical sensor that can provide the early detection of brine intrusion into formations used for domestic or agricultural water production. Several brine samples of NaCl-CaCl2 and NaCl-KCl were prepared at NaCl concentrations between 0.0 and 3.0 M. The effect of NaCl concentration on the signal-to-background ratio (SBR) and signal-to-noise ratio (SNR) for calcium (422.67 nm) and potassium (769.49 nm) emission lines was evaluated. Results show that, for a delay time of 300 ns and a gate width of 3 μs, the presence of and changes in NaCl concentration significantly affect the SBR and SNR for both emission lines. An increase in NaCl concentration from 0.0 to 3.0 M produced an increase in the SNR, whereas the SBR dropped continuously. The detection limits obtained for both elements were in the milligrams per liter range, suggesting that a NaCl-rich solution does not severely limit the ability of LIBS to detect trace amount of metal ions.

Label-free technology for the amplified detection of microRNA based on the allosteric hairpin DNA switch and hybridization chain reaction.

PubMed

Cai, Sheng; Cao, Zhijuan; Lau, Choiwan; Lu, Jianzhong

2014-11-21

By using the allosteric hairpin DNA switch, a novel assay for the detection of microRNA (miRNA) let-7a via a hybridization chain reaction (HCR) was introduced. Briefly, the hairpin DNA switch probe is a single-stranded DNA consisting of a streptavidin (SA) aptamer sequence, a target binding sequence and a certain sequence that acts as a trigger of the HCR. In the presence of target let-7a, the hairpin DNA switch would open and expose the stem region sequences, where a part of this sequence acts as initiator sequence strands for the HCR and triggers a cascade of hybridization events that yields nicked double helices analogous to alternating copolymers, another part is the SA aptamer sequence which activates its binding affinity to SA on SA-coated magnetic particles. The hybridization event could be sensitively detected via an instantaneous derivatization reaction between a special chemiluminescence (CL) reagent, 3,4,5-trimethoxylphenylglyoxal (TMPG) and the guanine nucleotides within the target, the hairpin DNA switch probe, and HCR helices to form an unstable CL intermediate for the generation of light. Our results show that the coupling of the hairpin DNA switch probe and the HCR for the amplified detection of let-7a achieves a better performance (e.g. wide linear response range: 0.1-1000 fmol, low detection limit: 0.1 fmol, and high specificity). Furthermore, this approach could be easily applied to the detection of let-7a in human lung cells, and extended to detect other types of miRNA and proteins such as PDGF based on aptamers. We believe such advancements will represent a significant step towards improved diagnostics and more personalized medical treatment.

Influence of crystal characteristics on the shock sensitivities of cyclotrimethylene trinitramine, cyclotetramethylene tetranitramine, and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetra-cyclo[5,5,0,03,1105,9]dodecane immersed in liquid

NASA Astrophysics Data System (ADS)

Li, Hongzhen; Xu, Rong; Kang, Bing; Li, Jinshan; Zhou, Xiaoqing; Zhang, Chaoyang; Nie, Fude

2013-05-01

The shock sensitivities of differently qualified cyclotrimethylene trinitramine (RDX), cyclotetramethylene tetranitramine(HMX), and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetra-cyclo[5,5,0,03,1105,9]dodecane (CL-20) immersed in liquid were determined by the large-scale gap tests, for systemic discussion on the influences of crystal characteristics on them. As a result, it shows that (1) the immersion of crystals in liquid leads to an obvious sensitivity decrease; (2) for all three explosives, their shock sensitivities are lowered with increasing their crystal apparent densities or decreasing their particle sizes, and almost not affected by particle morphologies; (3) the crystal twins are readily formed for HMX and the most distinct factor influencing its shock sensitivities; (4) it is found that the crystal apparent density affects most obviously the shock sensitivities for RDX and CL-20; and (5) CL-20, HMX, and RDX are less and less sensitive to shock, suggesting chemical components are also a determining factor.

Molecular emission in laser-induced breakdown spectroscopy: An investigation of its suitability for chlorine quantification on Mars

NASA Astrophysics Data System (ADS)

Vogt, D. S.; Rammelkamp, K.; Schröder, S.; Hübers, H. W.

2018-03-01

The intensity of the molecular CaCl emission in LIBS spectra is examined in order to evaluate its suitability for the detection of chlorine in a Martian environment. Various mixtures resembling Martian targets with varying Cl content are investigated under simulated Martian conditions. The reactions leading to the formation of CaCl are modeled based on reaction kinetics and are used to fit the measured CaCl band intensities. MgCl bands are also investigated as potential alternatives to CaCl, but no MgCl bands can be identified in samples containing both Mg and Cl. The study confirms that CaCl is well suited for the indirect detection of chlorine, but finds a strong dependence on the concentrations of Ca and Cl in the sample. Spectra from samples with a high chlorine concentration can have low-intensity CaCl emission due to a deficiency of Ca. A qualitative estimate of the sample composition is possible based on the ratio of the band intensity of CaCl to the intensity of Ca emission lines. Time-resolved measurements show that the CaCl concentration in the plasma is highest after about 1 μs.

Analysis of bakery products by laser-induced breakdown spectroscopy.

PubMed

Bilge, Gonca; Boyacı, İsmail Hakkı; Eseller, Kemal Efe; Tamer, Uğur; Çakır, Serhat

2015-08-15

In this study, we focused on the detection of Na in bakery products by using laser-induced breakdown spectroscopy (LIBS) as a quick and simple method. LIBS experiments were performed to examine the Na at 589 nm to quantify NaCl. A series of standard bread sample pellets containing various concentrations of NaCl (0.025-3.5%) were used to construct the calibration curves and to determine the detection limits of the measurements. Calibration graphs were drawn to indicate functions of NaCl and Na concentrations, which showed good linearity in the range of 0.025-3.5% NaCl and 0.01-1.4% Na concentrations with correlation coefficients (R(2)) values greater than 0.98 and 0.96. The obtained detection limits for NaCl and Na were 175 and 69 ppm, respectively. Performed experimental studies showed that LIBS is a convenient method for commercial bakery products to quantify NaCl concentrations as a rapid and in situ technique. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dark matter line emission constraints from NuSTAR observations of the bullet cluster

DOE PAGES

Riemer-Sørensen, S.; Wik, D.; Madejski, G.; ...

2015-08-27

Some dark matter candidates, e.g., sterile neutrinos, provide observable signatures in the form of mono-energetic line emission. Here, we present the first search for dark matter line emission in themore » $$3-80\\;\\mathrm{keV}$$ range in a pointed observation of the Bullet Cluster with NuSTAR. We do not detect any significant line emission and instead we derive upper limits (95% CL) on the flux, and interpret these constraints in the context of sterile neutrinos and more generic dark matter candidates. NuSTAR does not have the sensitivity to constrain the recently claimed line detection at $$3.5\\;\\mathrm{keV}$$, but improves on the constraints for energies of $$10-25\\;\\mathrm{keV}$$.« less

[Value of using polyethylene glycol in the indirect antiglobulin test with erythrocytes].

PubMed

Michalewska, B; Walewska, I; Seyfriedowa, H; Kuśnierz-Alejska, G

1991-01-01

A series of comparative investigations was carried out for establishing the value of the indirect antiglobulin test (IAT) in its first phase. The results showed that PEG, in relation to NaCl solution of low ionic strength, increased the reactivity of various antibodies of different specificity present in 72 studied sera. A significant superiority of IAT-PEG to IAT-BISS was noted in 45.8% of these sera. In search for antibodies in sera of 1160 patients IAT-PEG detected 7 antibodies not reacting in the IAT-LISS, and 5 of them had Rh system specificity, one was anti-K and one anti-Jka. Although the IAT-PEG was more sensitive than IAT-LISS in the detection of anti-Rh antibodies, it was less sensitive in this range than the enzymatic LEN test with which not only 5 of these antibodies were demonstrated but which detected also 8 antibodies not demonstrated in IAT-PEG or IAT-LISS. All 5 antibodies not detected by the IAT-PEG but demonstrated in the IAT-LISS were specific for the Lewis system. The per cent of reactions regarded as non-specific in the IAT-PEG was 1.3%. The IAT-PEG modification may be recommended as a sensitive, simple and specific method extending the possibilities of immunohematological diagnosis, especially in cases of post-transfusion reactions and in difficulties of interpretation connected with the occurrence of weakly positive reactions in the IAT-LISS.

Correlations between serum trypsinogen-2 and pancreatic cancer.

PubMed

Cao, Jianbiao; Xia, Changhong; Cui, Tingting; Guo, Hanbin; Li, Haoran; Ren, Yongqiang; Wang, Shuai

2015-01-01

To investigate associations be- tween serum trypsinogen-2, pancreatitis and pancreatic cancer (PC) and determine cutoff values for PC diagnosis. We recruited 88 patients from Internal Medicine/Surgical Departments of General Military Hospital of Beijing PLA between 12/2009 and 6/2010. Serum samples were collected preoperatively from 23 PC patients, 30 pancreatitis patients and 35 healthy controls. Enzyme-linked immunosorbent assay was used to detect trypsinogen-2 semiquantitatively. Serum trypsinogen-2 levels of PC and pancreatitis patients were significantly higher than those of controls (51.2 ± 80.3, 107.7 ± 98.1 vs. 1.0 ± 0.5, p = 0.03, p < 0.001) and significantly higher in pancreatitis vs. PC patients (107.7 ± 98.1 vs. 51.2 ± 80.3, p = 0.01). Higher Balthazar CT grades correlated with higher trypsinogen-2 in pancreatitis group. ROC curves for trypsinogen-2 revealed optimal cutoff value 1.8 as lower PC detection limit with 95.7% sensitivity and 91.4% specificity, and optimal cutoff value 19.9 for upper PC detection limit with 87.0% sensitivity and 97.1% specificity. Trypsinogen-2 levels correlated with pancreatic injury level. An AUC of 0.73 (95% Cl: 0.59-0.84, p = 0.002) distinguished PC from pancreatitis. Serum trypsinogen-2 is associated with PC and pancreatitis. Levels between 1.8 μg/L and 19.9 μg/L strongly suggest PC. Detection of serum trypsinogen-2 may provide simple, sensitive, specific non-invasive initial screening for early PC diagnosis.

IkappaB is a sensitive target for oxidation by cell-permeable chloramines: inhibition of NF-kappaB activity by glycine chloramine through methionine oxidation.

PubMed

Midwinter, Robyn G; Cheah, Fook-Choe; Moskovitz, Jackob; Vissers, Margret C; Winterbourn, Christine C

2006-05-15

Hypochlorous acid (HOCl) is produced by the neutrophil enzyme, myeloperoxidase, and reacts with amines to generate chloramines. These oxidants react readily with thiols and methionine and can affect cell-regulatory pathways. In the present study, we have investigated the ability of HOCl, glycine chloramine (Gly-Cl) and taurine chloramine (Tau-Cl) to oxidize IkappaBalpha, the inhibitor of NF-kappaB (nuclear factor kappaB), and to prevent activation of the NF-kappaB pathway in Jurkat cells. Glycine chloramine (Gly-Cl) and HOCl were permeable to the cells as determined by oxidation of intracellular GSH and inactivation of glyceraldehyde-3-phosphate dehydrogenase, whereas Tau-Cl showed no detectable cell permeability. Both Gly-Cl (20-200 muM) and HOCl (50 microM) caused oxidation of IkappaBalpha methionine, measured by a shift in electrophoretic mobility, when added to the cells in Hanks buffer. In contrast, a high concentration of Tau-Cl (1 mM) in Hanks buffer had no effect. However, Tau-Cl in full medium did modify IkappaBalpha. This we attribute to chlorine exchange with other amines in the medium to form more permeable chloramines. Oxidation by Gly-Cl prevented IkappaBalpha degradation in cells treated with TNFalpha (tumour necrosis factor alpha) and inhibited nuclear translocation of NF-kappaB. IkappaBalpha modification was reversed by methionine sulphoxide reductase, with both A and B forms required for complete reduction. Oxidized IkappaBalpha persisted intracellularly for up to 6 h. Reversion occurred in the presence of cycloheximide, but was prevented if thioredoxin reductase was inhibited, suggesting that it was due to endogenous methionine sulphoxide reductase activity. These results show that cell-permeable chloramines, either directly or when formed in medium, could regulate NF-kappaB activation via reversible IkappaBalpha oxidation.

Effect of Chorda Tympani Nerve Transection on Salt Taste Perception in Mice

PubMed Central

Ishiwatari, Yutaka; Theodorides, Maria L.; Bachmanov, Alexander A.

2011-01-01

Effects of gustatory nerve transection on salt taste have been studied extensively in rats and hamsters but have not been well explored in the mouse. We examined the effects of chorda tympani (CT) nerve transection on NaCl taste preferences and thresholds in outbred CD-1 mice using a high-throughput phenotyping method developed in our laboratory. To measure taste thresholds, mice were conditioned by oral self-administration of LiCl or NaCl and then presented with NaCl concentration series in 2-bottle preference tests. LiCl-conditioned and control NaCl-exposed mice were given bilateral transections of the CT nerve (LiCl-CTX, NaCl-CTX) or were left intact as controls (LiCl-CNT, NaCl-CNT). After recovery from surgery, mice received a concentration series of NaCl (0–300 mM) in 48-h 2-bottle tests. CT transection increased NaCl taste thresholds in LiCl-conditioned mice and eliminated avoidance of concentrated NaCl in control NaCl-exposed mice. This demonstrates that in mice, the CT nerve is important for detection and recognition of NaCl taste and is necessary for the normal avoidance of high concentrations of NaCl. The results of this experiment also show that the method of high-throughput phenotyping of salt taste thresholds is suitable for detecting changes in the taste periphery in mouse genetic studies. PMID:21743094

Strategies for oxychlorine removal to facilitate pyrolytic organic matter analysis in subsurface oxychlorine-rich brines on Earth and Mars

NASA Astrophysics Data System (ADS)

Chou, L.; Kenig, F. P. H.; Jackson, W. A.

2017-12-01

The ubiquity of oxychlorine salts in the Martian soil significantly hampers our ability to unambiguously detect and characterize organic matter (OM) that is of Martian origin via pyrolysis. The Sample Analysis at Mars (SAM) instrument suite onboard the Curiosity Rover detected chlorinated and non-chlorinated inorganic and organic compounds (HCl, CO2, C1-C4 chloroalkanes, chlorobenzenes) at Gale Crater. The C1 to C3 chloroalkanes have been attributed to the reaction between the oxychlorines and OM deriving from the SAM instrument suite. Chlorobenzenes and dichloroalkanes, on the other hand, were observed at elevated levels at Gale Crater and are hypothesized to be the first indigenous OM detected on Mars. However, due to complex chlorination and oxidation reactions in the SAM pyrolysis oven, the precursor molecules to these chlorohydrocarbons are unknown. In order to facilitate the detection of OM in ClO4-rich samples on Mars, we explore various strategies, such as using strong base anion (SBA) exchange resins, to remove ClO4- from a Mars analog sample. This sample was obtained from a subsurface brine beneath the frozen Lake Vida (East Antarctica). Lake Vida brine (LVBr) contains abundant DOC at 48.2 mmol·L-1 and ClO4- at 49 µg•L-1. Resin-treated samples were analyzed via solid phase microextraction (SPME) gas chromatography-mass spectrometry (GC-MS). The SBA resin successfully removed ClO4- to below detection level from standard brine solution (3M NaCl + 50 µg•L-1 ClO4-) and LVBr using a minimum of 3.4 mL of resin volume per 100 mL of sample volume. Although the abundance of CO2, CH2Cl2 and HCl formed via the oxidation and chlorination of OM during SPME GC-MS analysis of resin-treated LVBr was significantly reduced, it was not completely eliminated. This suggests that the degradation of other oxychlorines (i.e. ClO3-) may also be obstructing our ability to detect OM indigenous to LVBr. The average level of ClO3- in LVBr after resin treatment was 16.7 ppb. We attempt to remove ClO3- using a nitrate-specific resin, as ClO3-specific resins are not currently manufactured, in an effort to further reduce the levels of ClO3- from the brine sample, allowing for the downstream pyrolytic analysis of OM present in LVBr, as well as oxychlorine-rich samples on Mars.

Multilayers enzyme-coated carbon nanotubes as biolabel for ultrasensitive chemiluminescence immunoassay of cancer biomarker.

PubMed

Bi, Sai; Zhou, Hong; Zhang, Shusheng

2009-06-15

A novel and ultrasensitive chemiluminescence immunoassay (CLIA) method based on multiple enzyme layers assembled multiwall carbon nanotubes (MWCNTs) as signal amplification labels was developed by employing luminol-H(2)O(2)-HRP-bromophenol blue (BPB) enhanced chemiluminescence (CL) system for the detection of a cancer biomarker in human serum samples, as exemplified by the measurement of alpha-fetoprotein (AFP) as a model protein. In this study, horseradish peroxidase (HRP) was assembled onto MWCNTs templates layer-by-layer (LBL) through electrostatic interactions with polyion PDDA, and further conjugated with AFP secondary antibodies (Ab(2)) as the enzyme label. The resulting LBL assembly could maximize the ratio of HRP/Ab(2) which could amplify the sensitivity greatly. To the best of our knowledge, it was the first time for this strategy applied in CLIA to date. Under the optimum conditions of luminol-H(2)O(2)-HRP-BPB CL system and the sandwich immunoreactions, a linear range from 0.02 to 2.0 ng/mL (R=0.9980) was obtained with the detection limit of 8.0 pg/mL (3sigma) which was two orders of magnitude lower than standard ELISA method. Furthermore, accurate detection of AFP in human serum samples was also demonstrated by comparison to ELISA assays. From the above results, such signal amplification strategy proposed by the novel CNT-LBL enzyme label showed an excellent promise for ultrasensitive detection of cancer biomarkers in clinical laboratory.

Molecularly imprinted sensor based on Russian Matryoshka structured molecules for enhanced specific identification and double amplification in ultra-trace Tb3+ determination.

PubMed

Li, Jianping; Yang, Bin; Pan, Hongcheng; Xu, Guobao

2018-06-30

The selective and sensitive detection of rare earth elements is thought to be difficult because the concentration of those elements in the sample is commonly at a low level and they normally have severe mutual interference which is caused by homologous chemical properties. In this study, a novel molecularly imprinted polymer (MIP) sensor was fabricated for highly sensitive and selective determination of ultra-trace Tb 3+ . The Tb 3+ -ethylenediaminetetraacetic acid complex (Tb-EDTA) as the template molecule was incorporated into mono-6-mercapto-β-cyclodextrin (mono-6-SH-β-CD) to form a Russian Matryoshka (RM)-structured molecule (CD/Tb-EDTA). Titanium isopropoxide was utilized in vapor sol-gel polymerization to construct MIP membrane. Moreover, the selectivity of the RM MIP sensor was remarkably enhanced by the "triple-selectivity" recognition of EDTA-to-Tb 3+ , β-CD-to-(Tb-EDTA), and 3D cavity-to-(CD/Tb-EDTA), while the sensitivity of the MIP sensor was significantly improved by ECL signal enhancement based on double amplification, in other words, the electrochemiluminescence resonance energy transfer (ECL-RET) between the ECL donor of CD/Tb-EDTA and the ECL acceptor of Ru(bpy) 3 2+ , and the ECL enhancement by the co-reactant of CD/Tb-EDTA on Ru(bpy) 3 Cl 2 . When the imprinted cavities were occupied by Tb-EDTA during rebinding, the host-guest inclusion structured complex was formed and the ECL intensities produced by the Ru(bpy) 3 Cl 2 ECL system increased with increasing concentration of Tb-EDTA. The proposed sensor was used for quantitative analysis of Tb 3+ with concentrations ranging from 8.00 × 10 -13 mol/L to 4.00 × 10 -9 mol/L and successfully applied to detect Tb 3+ in seawater samples. The detection limit of the sensor was found to be 3.90 × 10 -13 mol/L (DL = 3δ b /K), which is lower than previously reported values. Thus, the fabricated sensor is feasible for practical applications. Copyright © 2018 Elsevier B.V. All rights reserved.

An enhanced chemiluminescence resonance energy transfer system based on target recycling G-guadruplexes/hemin DNAzyme catalysis and its application in ultrasensitive detection of DNA.

PubMed

Chen, Jia; Huang, Yong; Vdovenko, Marina; Sakharov, Ivan Yu; Su, Guifa; Zhao, Shulin

2015-06-01

An enhanced chemiluminescence resonance energy transfer (CRET) system based on target recycling G-guadruplexes/hemin DNAzyme catalysis was developed for ultrasensitive detection of DNA. CRET system consists of luminol as chemiluminescent donor, and fluorescein isothiocyanate (FITC) as acceptor. The sensitive detection was achieved by using the system consisted of G-riched DNA, blocker DNA, and the Nb.BbvCI biocatalyst. Upon addition of target DNA to the system, target DNA hybridizes with the quasi-circular DNA structure, and forms a DNA duplex. The formation of DNA duplex triggers selective enzymatic cleavage of quasi-circular DNA by Nb.BbvCI, resulting in the release of target DNA and two G-riched DNAzyme segments. Released target DNA then hybridizes with another quasi-circular DNA structure to initiate the cleavage of the quasi-circular DNA structure. Eventually, each target DNA can go through many cycles, resulting in the digestion of many quasi-circular DNA structures, generating many G-riched DNAzyme segments. G-riched DNAzyme segment products assemble with hemin to form stable hemin/G-quadruplexes that exhibit peroxidase-like activity which can catalyze the oxidation of luminol by H2O2 to produce CL signals. In the presence of FITC, CL of luminol can excite FITC molecules, and thus produced CRET between the luminol and FITC. This unique analysis strategy gives a detection limit down to 80 fM, which is at least four orders of magnitude lower than that of unamplified DNA detection methods. Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation of an Efficient Ratiometric Fluorescent Nanoprobe (m-CDs@[Ru(bpy)3]2+) for Visual and Specific Detection of Hypochlorite on Site and in Living Cells.

PubMed

Zhan, Yuanjin; Luo, Fang; Guo, Longhua; Qiu, Bin; Lin, Yuhong; Li, Juan; Chen, Guonan; Lin, Zhenyu

2017-11-22

Hypochlorite (ClO - ) is one of the most important reactive oxygen species (ROS), which plays an important role in sustaining human innate immunity during microbial invasion. Moreover, ClO - is a powerful oxidizer for water treatment. The safety of drinking water is closely related to its content. Herein, m-phenylenediamine (mPD) is used as a precursor to prepare carbon dots (named m-CDs) with highly fluorescent quantum yield (31.58% in water), and our investigation shows that the strong fluorescent emission of m-CDs can be effectively quenched by ClO - . Based on these findings, we developed a novel fluorescent nanoprobe (m-CDs) for highly selective detection of ClO - . The linear range was from 0.05 to 7 μM (R 2 = 0.998), and the limit of detection (S/N = 3) was as low as 0.012 μM. Moreover, a portable agarose hydrogel solid matrix-based ratiometric fluorescent nanoprobe (m-CDs@[Ru(bpy) 3 ] 2+ ) sensor was subsequently developed for visual on-site detection of ClO - with the naked eyes under a UV lamp, suggesting its potential in practical application with low cost and excellent performance in water quality monitoring. Additionally, intracellular detection of exogenous ClO - was demonstrated via ratiometric imaging microscopy.

Manual-slide-engaged paper chip for parallel SERS-immunoassay measurement of clenbuterol from swine hair.

PubMed

Zheng, Tingting; Gao, Zhigang; Luo, Yong; Liu, Xianming; Zhao, Weijie; Lin, Bingcheng

2016-02-01

Clenbuterol (CL), as a feed additive, has been banned in many countries due to its potential threat to human health. In detection of CL, a fast, low-cost technique with high accuracy and specificity would be ideal for its administrative on-field inspections. Among the attempts to pursue a reliable detection tool of CL, a technique that combines surface enhanced Raman spectroscopy (SERS) and immunoassay, is close to meet the requirements as above. However, multiple steps of interactions between CL analyte, antibody, and antigen are involved in this method, and under conventional setup, the operation of SERS/immunoassay were unwieldy. In this paper, to facilitate a more manageable sample manipulation for SERS-immunoassay measurement, a 3D paper chip was suggested. A switch-on-chip multilayered (abbreviated as SoCM-) microfluidic paper-based analysis device (μPad) was fabricated to provide operators with manual switches on the interactions between different microfluids. Besides, on a detection slip we made on the main body of our SoCM-μPad, antigen was anchored in pattern. With this architecture, multistep interactions between the CL analyte in swine hair extract and the SERS probe-modified antibody and antigen, were managed for on-chip SERS-immunoassay detection. This would be very attractive for fast, cheap, accurate, and on-site specific detection of CL from real samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Integrated multi-ISE arrays with improved sensitivity, accuracy and precision

NASA Astrophysics Data System (ADS)

Wang, Chunling; Yuan, Hongyan; Duan, Zhijuan; Xiao, Dan

2017-03-01

Increasing use of ion-selective electrodes (ISEs) in the biological and environmental fields has generated demand for high-sensitivity ISEs. However, improving the sensitivities of ISEs remains a challenge because of the limit of the Nernstian slope (59.2/n mV). Here, we present a universal ion detection method using an electronic integrated multi-electrode system (EIMES) that bypasses the Nernstian slope limit of 59.2/n mV, thereby enabling substantial enhancement of the sensitivity of ISEs. The results reveal that the response slope is greatly increased from 57.2 to 1711.3 mV, 57.3 to 564.7 mV and 57.7 to 576.2 mV by electronic integrated 30 Cl- electrodes, 10 F- electrodes and 10 glass pH electrodes, respectively. Thus, a tiny change in the ion concentration can be monitored, and correspondingly, the accuracy and precision are substantially improved. The EIMES is suited for all types of potentiometric sensors and may pave the way for monitoring of various ions with high accuracy and precision because of its high sensitivity.

[Effectiveness of human papillomavirus genotyping for detection of high-grade anal intraepithelial neoplasia compared to anal cytology].

PubMed

Padilla-España, Laura; Repiso-Jiménez, Juan Bosco; Fernández-Sánchez, Fernando; Pereda, Teresa; Rivas-Ruiz, Francisco; Fernández-Morano, Teresa; de la Torre-Lima, Javier; Palma, Fermín; Redondo, Maximino; de Troya-Martín, Magdalena

2016-01-01

The incidence of high-grade anal intraepithelial neoplasia (HGAIN) -with an aetiological based on high-risk types of human papillomavirus- is increasing in some high-risk groups. Screening for HGAIN includes routine anal cytology and, more recently, HPV genotyping. The main objective of this study was to determine the sensitivity and specificity of anal cytology and HPV genotyping for the detection of HGAIN. This is a study to determine the correlation of cytological and microbiological findings with anal biopsy findings in a cohort of patients at high risk of developing AIN referred to the department of sexually transmitted infections of the Hospital Costa del Sol, Spain, between January 2008 and December 2014. Of the 151 patients subjected to screening, a total of 92 patients, all of them with the result of three screening test (anal cytology, genotyping and biopsy) were included in the study. Just under two-thirds (62%) of them were HIV-positive. The sensitivity and specificity of anal cytology to detect HGAIN were 52.8 and 85.7%, respectively (k: 0.328), and 78 and 62.8% to detect two or more HPV oncogenic genotypes (k: 0.417). The detection of oncogenic HPV genotypes allowed the identification of 23 new cases of HGAIN that had been underdiagnosed with anal cytology, with 14 cases containing at least three high-risk genotypes. Anal cytology did not show enough sensitivity in HGAIN screening. HPV genotyping has shown to be a useful tool to detect HGAIN cases, although it could lead to an over-diagnosis as a solitary screening procedure. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Impact of source collinearity in simulated PM 2.5 data on the PMF receptor model solution

NASA Astrophysics Data System (ADS)

Habre, Rima; Coull, Brent; Koutrakis, Petros

2011-12-01

Positive Matrix Factorization (PMF) is a factor analytic model used to identify particle sources and to estimate their contributions to PM 2.5 concentrations observed at receptor sites. Collinearity in source contributions due to meteorological conditions introduces uncertainty in the PMF solution. We simulated datasets of speciated PM 2.5 concentrations associated with three ambient particle sources: "Motor Vehicle" (MV), "Sodium Chloride" (NaCl), and "Sulfur" (S), and we varied the correlation structure between their mass contributions to simulate collinearity. We analyzed the datasets in PMF using the ME-2 multilinear engine. The Pearson correlation coefficients between the simulated and PMF-predicted source contributions and profiles are denoted by " G correlation" and " F correlation", respectively. In sensitivity analyses, we examined how the means or variances of the source contributions affected the stability of the PMF solution with collinearity. The % errors in predicting the average source contributions were 23, 80 and 23% for MV, NaCl, and S, respectively. On average, the NaCl contribution was overestimated, while MV and S contributions were underestimated. The ability of PMF to predict the contributions and profiles of the three sources deteriorated significantly as collinearity in their contributions increased. When the mean of NaCl or variance of NaCl and MV source contributions was increased, the deterioration in G correlation with increasing collinearity became less significant, and the ability of PMF to predict the NaCl and MV loading profiles improved. When the three factor profiles were simulated to share more elements, the decrease in G and F correlations became non-significant. Our findings agree with previous simulation studies reporting that correlated sources are predicted with higher error and bias. Consequently, the power to detect significant concentration-response estimates in health effect analyses weakens.

The area postrema does not modulate the long-term salt sensitivity of arterial pressure.

PubMed

Collister, J P; Osborn, J W

1998-10-01

The hindbrain circumventricular organ, the area postrema (AP), receives multiple signals linked to body fluid homeostasis. In addition to baroreceptor input, AP cells contain receptors for ANG II, vasopressin, and atrial natriuretic peptide. Hence, it has been proposed that the AP is critical in long-term adjustments in sympathetic outflow in response to changes in dietary NaCl. The present study was designed to test the hypothesis that long-term control of arterial pressure over a range of dietary NaCl requires an intact AP. Male Sprague-Dawley rats were randomly selected for lesion of the AP (APx) or sham lesion. Three months later, rats were instrumented with radiotelemetry transmitters for continuous monitoring of mean arterial pressure (MAP) and heart rate and were placed in individual metabolic cages. Rats were given 1 wk postoperative recovery. The dietary salt protocol consisted of a 7-day period of 1.0% NaCl (control), 14 days of 4.0% NaCl (high), 7 days of 1.0% NaCl, and finally 14 days of 0.1% NaCl (low). The results are reported as the average arterial pressure observed on the last day of the given dietary salt period: APx (n = 7) 114 +/- 2 (1.0%), 110 +/- 3 (4.0%), 110 +/- 3 (1.0%), and 114 +/- 4 (0.1%) mmHg; sham (n = 6) 115 +/- 2 (1.0%), 114 +/- 3 (4.0%), 111 +/- 3 (1. 0%), and 113 +/- 2 (0.1%) mmHg. Neither group of rats demonstrated significant changes in MAP throughout the entire dietary salt protocol. Furthermore, no significant differences in MAP were detected between groups throughout the protocol. All lesions were histologically verified. These results suggest that the area postrema plays no role in long-term control of arterial pressure during chronic changes in dietary salt.

Arsenite and Cadmium Activate MAPK/ERK via Membrane Estrogen Receptors and G-Protein Coupled Estrogen Receptor Signaling in Human Lung Adenocarcinoma Cells.

PubMed

Huff, Mary O; Todd, Sarah L; Smith, Aaron L; Elpers, Julie T; Smith, Alexander P; Murphy, Robert D; Bleser-Shartzer, Allison S; Hoerter, Jacob E; Radde, Brandie N; Klinge, Carolyn M

2016-07-01

Epidemiological evidence indicates that cadmium and arsenic exposure increase lung cancer risk. Cadmium and arsenic are environmental contaminants that act as endocrine disruptors (EDs) by activating estrogen receptors (ERs) in breast and other cancer cell lines but their activity as EDs in lung cancer is untested. Here, we examined the effect of cadmium chloride (CdCl2) and sodium arsenite (NaAsO2) on the proliferation of human lung adenocarcinoma cell lines. Results demonstrated that both CdCl2 and NaAsO2 stimulated cell proliferation at environmentally relevant nM concentrations in a similar manner to 17β-estradiol (E2) in H1793, H2073, and H1944 cells but not in H1792 or H1299 cells. Further studies in H1793 cells showed that 100 nM CdCl2 and NaAsO2 rapidly stimulated mitogen-activated protein kinase (MAPK, extracellular-signal-regulated kinases) phosphorylation with a peak detected at 15 min. Inhibitor studies suggest that rapid MAPK phosphorylation by NaAsO2, CdCl2, and E2 involves ER, Src, epidermal growth factor receptor, and G-protein coupled ER (GPER) in a pertussis toxin-sensitive pathway. CdCl2 and E2 activation of MAPK may also involve ERβ. This study supports the involvement of membrane ER and GPER signaling in mediating cellular responses to environmentally relevant nM concentrations of CdCl2 and NaAsO2 in lung adenocarcinoma cells. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Selective and Sensitive Detection of Cyanide Based on the Displacement Strategy Using a Water-Soluble Fluorescent Probe.

PubMed

La, Ming; Hao, Yuanqiang; Wang, Zhaoyang; Han, Guo-Cheng; Qu, Lingbo

2016-01-01

A water-soluble fluorescent probe (C-GGH) was used for the highly sensitive and selective detection of cyanide (CN(-)) in aqueous media based on the displacement strategy. Due to the presence of the recognition unit GGH (Gly-Gly-His), the probe C-GGH can coordinate with Cu(2+) and consequently display ON-OFF type fluorescence response. Furthermore, the in situ formed nonfluorescent C-GGH-Cu(2+) complex can act as an effective OFF-ON type fluorescent probe for sensing CN(-) anion. Due to the strong binding affinity of CN(-) to Cu(2+), CN(-) can extract Cu(2+) from C-GGH-Cu(2+) complex, leading to the release of C-GGH and the recovery of fluorescent emission of the system. The probe C-GGH-Cu(2+) allowed detection of CN(-) in aqueous solution with a LOD (limit of detection) of 0.017 μmol/L which is much lower than the maximum contaminant level (1.9 μmol/L) for CN(-) in drinking water set by the WHO (World Health Organization). The probe also displayed excellent specificity for CN(-) towards other anions, including F(-), Cl(-), Br(-), I(-), SCN(-), PO4 (3-), N3 (-), NO3 (-), AcO(-), SO4 (2-), and CO3 (2-).

Highly selective visual monitoring of hazardous fluoride ion in aqueous media using thiobarbituric-capped gold nanoparticles.

PubMed

Boken, Jyoti; Thatai, Sheenam; Khurana, Parul; Prasad, Surendra; Kumar, Dinesh

2015-01-01

The rapid, selective and sensitive measurement and monitoring of hazardous materials as analytes are the central themes in the development of any successful analytical technique. With this aim, we have synthesized the thiobarbituric-capped gold nanoparticles (TBA-capped Au NPs) involving chemical reduction of HAuCl4 using 2-thiobarbituric acid (TBA) as a reducing and capping agent. The morphology of the TBA-capped Au NPs was confirmed using transmission electron microscope images. For the first time this article reports that the developed TAB-capped Au NPs displays selective, ultrafast and sensitive colorimetric detection of fluoride ion in aqueous samples. The detection of fluoride ion was confirmed by the disappearance of the localized surface plasmon resonance (LSPR) band at 554 nm using UV-vis spectroscopy. The interaction of F(-) with TBA-capped Au NPs in aqueous solution has also been confirmed by Raman and FTIR spectroscopy. One of the most exciting accomplishments is the visual detection limit for fluoride ion has been found to be 10 mM at commonly acceptable water pH range 7-8. The whole detection procedure takes not more than 40s with excellent selectivity providing sample throughput of more than 60 per hour. Copyright © 2014 Elsevier B.V. All rights reserved.

Utilization of wavelength-shifting fibers coupled to ZnS(Ag) and plastic scintillator for simultaneous detection of alpha/beta particles

NASA Astrophysics Data System (ADS)

Ifergan, Y.; Dadon, S.; Israelashvili, I.; Osovizky, A.; Gonen, E.; Yehuda-Zada, Y.; Smadja, D.; Knafo, Y.; Ginzburg, D.; Kadmon, Y.; Cohen, Y.; Mazor, T.

2015-06-01

Low level radioactive surface contamination measurements require lightweight, large area and high efficiency detector. In most existing scintillation detectors there is a tradeoff between effective area and scintillation light collection. By using wavelength shifting (WLS) fibers the scintillation light may be collected efficiently also in a large area detector. In this study, WLS fibers were coupled to a beta sensitive plastic scintillator layer and to a alpha sensitive silver-activated zinc sulfide ZnS(Ag) layer for detecting both alpha and beta particles. The WLS fibers collect the scintillation light from the whole detector and transfer it to a single PMT. This first prototype unique configuration enables monitoring radioactive contaminated surfaces by both sides of the detector and provides high gamma rejection. In this paper, the detector structure, as well as the detector's measured linear response, will be described. The measured detection efficiency of 238Pu alpha particles (5.5 MeV) is 63%. The measured detection efficiency for beta particles is 89% for 90Sr-90Y (average energy of 195.8 keV, 934.8 keV), 50% for 36Cl (average energy of 251.3 keV), and 35% for 137Cs (average energy of 156.8 keV).

[Prevalence of metallo-beta-lactamase in carbapenem resistant Pseudomonas aeruginosa at a university hospital of Buenos Aires City].

PubMed

Pagniez, G; Radice, M; Cuirolo, A; Rodríguez, O; Rodríguez, H; Vay, C; Famiglietti, A; Gutkind, G

2006-01-01

The present study was conducted to estimate the prevalence of metallo-beta-lactamases in 91 consecutive carbapenem resistant Pseudomonas aeruginosa isolates, recovered from inpatients at Hospital de Clínicas in Buenos Aires. Both, phenotypic and genotypic methods detected the presence of carbapenemases in 10 (11%) isolates, corresponding to VIM-11 in 7/10 and VIM-2 in the others. Codifying genes were all included in class 1 integrons, upstream genes coding for aminoglycoside modifying enzymes. One hundred percent sensitivity and specificity was achieved by the metallo-beta-lactamases phenotypic screening method using EDTA (1 micromol) disks in the Pseudomonas aeruginosa isolates included in this study. Sensitivity to aztreonam in carbapenem resistant isolates was suspicious of the presence of these enzymes.

3D printed stretchable capacitive sensors for highly sensitive tactile and electrochemical sensing

NASA Astrophysics Data System (ADS)

Li, Kai; Wei, Hong; Liu, Wenguang; Meng, Hong; Zhang, Peixin; Yan, Chaoyi

2018-05-01

Developments of innovative strategies for the fabrication of stretchable sensors are of crucial importance for their applications in wearable electronic systems. In this work, we report the successful fabrication of stretchable capacitive sensors using a novel 3D printing method for highly sensitive tactile and electrochemical sensing applications. Unlike conventional lithographic or templated methods, the programmable 3D printing technique can fabricate complex device structures in a cost-effective and facile manner. We designed and fabricated stretchable capacitive sensors with interdigital and double-vortex designs and demonstrated their successful applications as tactile and electrochemical sensors. Especially, our stretchable sensors exhibited a detection limit as low as 1 × 10-6 M for NaCl aqueous solution, which could have significant potential applications when integrated in electronics skins.

Sub-micro-liter Electrochemical Single-Nucleotide-Polymorphism Detector for Lab-on-a-Chip System

NASA Astrophysics Data System (ADS)

Tanaka, Hiroyuki; Fiorini, Paolo; Peeters, Sara; Majeed, Bivragh; Sterken, Tom; de Beeck, Maaike Op; Hayashi, Miho; Yaku, Hidenobu; Yamashita, Ichiro

2012-04-01

A sub-micro-liter single-nucleotide-polymorphism (SNP) detector for lab-on-a-chip applications is developed. This detector enables a fast, sensitive, and selective SNP detection directly from human blood. The detector is fabricated on a Si substrate by a standard complementary metal oxide semiconductor/micro electro mechanical systems (CMOS/MEMS) process and Polydimethylsiloxane (PDMS) molding. Stable and reproducible measurements are obtained by implementing an on-chip Ag/AgCl electrode and encapsulating the detector. The detector senses the presence of SNPs by measuring the concentration of pyrophosphoric acid generated during selective DNA amplification. A 0.5-µL-volume detector enabled the successful performance of the typing of a SNP within the ABO gene using human blood. The measured sensitivity is 566 pA/µM.

A redox-mediated chromogenic reaction and application in immunoassay.

PubMed

Yu, Ru-Jia; Ma, Wei; Peng, Mao-Pan; Bai, Zhi-Shan; Long, Yi-Tao

2016-08-31

A novel redox-mediated chromogenic reaction was demonstrated based on the reaction between HAuCl4 and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), which generate various color responses from red to green in the resulting solutions. Various redox substance could be used to mediate the reaction and trigger a distinct color response. We established a sensitive hydrogen peroxide colorimetric sensor based on the redox-mediated chromogenic reaction and depicted the application both in detection of enzyme and in an immunoassay. Combining the traditional chromogenic reagent with gold nanoparticles, our assay has the advantage in short response time (within three minutes), high sensitivity (10(-12) g mL(-1) for HBsAg) and stability. Copyright © 2016. Published by Elsevier B.V.

3D printed stretchable capacitive sensors for highly sensitive tactile and electrochemical sensing.

PubMed

Li, Kai; Wei, Hong; Liu, Wenguang; Meng, Hong; Zhang, Peixin; Yan, Chaoyi

2018-05-04

Developments of innovative strategies for the fabrication of stretchable sensors are of crucial importance for their applications in wearable electronic systems. In this work, we report the successful fabrication of stretchable capacitive sensors using a novel 3D printing method for highly sensitive tactile and electrochemical sensing applications. Unlike conventional lithographic or templated methods, the programmable 3D printing technique can fabricate complex device structures in a cost-effective and facile manner. We designed and fabricated stretchable capacitive sensors with interdigital and double-vortex designs and demonstrated their successful applications as tactile and electrochemical sensors. Especially, our stretchable sensors exhibited a detection limit as low as 1 × 10 -6 M for NaCl aqueous solution, which could have significant potential applications when integrated in electronics skins.

First evidence of pep solar neutrinos by direct detection in Borexino.

PubMed

Bellini, G; Benziger, J; Bick, D; Bonetti, S; Bonfini, G; Bravo, D; Buizza Avanzini, M; Caccianiga, B; Cadonati, L; Calaprice, F; Carraro, C; Cavalcante, P; Chavarria, A; Chepurnov, A; D'Angelo, D; Davini, S; Derbin, A; Etenko, A; Fomenko, K; Franco, D; Galbiati, C; Gazzana, S; Ghiano, C; Giammarchi, M; Goeger-Neff, M; Goretti, A; Grandi, L; Guardincerri, E; Hardy, S; Ianni, Aldo; Ianni, Andrea; Korablev, D; Korga, G; Koshio, Y; Kryn, D; Laubenstein, M; Lewke, T; Litvinovich, E; Loer, B; Lombardi, F; Lombardi, P; Ludhova, L; Machulin, I; Manecki, S; Maneschg, W; Manuzio, G; Meindl, Q; Meroni, E; Miramonti, L; Misiaszek, M; Montanari, D; Mosteiro, P; Muratova, V; Oberauer, L; Obolensky, M; Ortica, F; Otis, K; Pallavicini, M; Papp, L; Perasso, L; Perasso, S; Pocar, A; Quirk, J; Raghavan, R S; Ranucci, G; Razeto, A; Re, A; Romani, A; Sabelnikov, A; Saldanha, R; Salvo, C; Schönert, S; Simgen, H; Skorokhvatov, M; Smirnov, O; Sotnikov, A; Sukhotin, S; Suvorov, Y; Tartaglia, R; Testera, G; Vignaud, D; Vogelaar, R B; von Feilitzsch, F; Winter, J; Wojcik, M; Wright, A; Wurm, M; Xu, J; Zaimidoroga, O; Zavatarelli, S; Zuzel, G

2012-02-03

We observed, for the first time, solar neutrinos in the 1.0-1.5 MeV energy range. We determined the rate of pep solar neutrino interactions in Borexino to be 3.1±0.6{stat}±0.3{syst}  counts/(day·100  ton). Assuming the pep neutrino flux predicted by the standard solar model, we obtained a constraint on the CNO solar neutrino interaction rate of <7.9  counts/(day·100  ton) (95% C.L.). The absence of the solar neutrino signal is disfavored at 99.97% C.L., while the absence of the pep signal is disfavored at 98% C.L. The necessary sensitivity was achieved by adopting data analysis techniques for the rejection of cosmogenic {11}C, the dominant background in the 1-2 MeV region. Assuming the Mikheyev-Smirnov-Wolfenstein large mixing angle solution to solar neutrino oscillations, these values correspond to solar neutrino fluxes of (1.6±0.3)×10{8}  cm{-2} s^{-1} and <7.7×10{8}  cm{-2} s{-1} (95% C.L.), respectively, in agreement with both the high and low metallicity standard solar models. These results represent the first direct evidence of the pep neutrino signal and the strongest constraint of the CNO solar neutrino flux to date.

Controllable preparation of copper phthalocyanine single crystal nano column and its chlorine gas sensing properties

NASA Astrophysics Data System (ADS)

Zhao, Jianhong; Qiao, Zhenfang; Zhang, Yumin; Zou, Taoyu; Yu, Leiming; Luo, Li; Wang, Xiaoyan; Yang, Yiji; Wang, Hai; Tang, Libin

2016-09-01

The unsubstituted copper phthalocyanine (CuPc) single crystal nano columns were fabricated for the first time as chlorine (Cl2) gas sensors in this paper. The nano columns of CuPc have been prepared on different substrates via template-free physical vapor deposition (PVD) approach. The growth mechanism of CuPc nano column on quartz was explored and the same condition used on other substrates including glass, sapphire (C-plane<0001>, M-plane<10 1 ¯ 0 >, R-plane<1 1 ¯ 02 >), Si and SiO2/Si came to a same conclusion, which confirmed that the aligned growth of CuPc nano column is not substrate-dependent. And then the CuPc nano column with special morphology was integrated as in-situ sensor device which exhibits high sensitivity and selectivity towards Cl2 at room temperature with a minimum detection limit as low as 0.08 ppm. The response of sensor was found to increase linearly (26 ˜659 % ) with the increase for Cl2 within concentration range (0.08 ˜4.0 ppm ) . These results clearly demonstrate the great potential of the nano column growth and device integration approach for sensor device.

Molecular structure, supramolecular association and anion sensing by chlorodiorganotin(IV) methylferrocenyldithiocarbamates

NASA Astrophysics Data System (ADS)

Yadav, Reena; Awasthi, Mahendra Kumar; Singh, Amita; Kociok-Köhn, Gabriele; Trivedi, Manoj; Prasad, Rajendra; Shahid, Mohammad; Kumar, Abhinav

2017-10-01

Three new chlorodiorganotin(IV) methylferrocenyl dithiocarbamate complexes viz. [(FcCH2)(CH2CH2OH)NCS2SnMe2(Cl)] (1), [(FcCH2)(CH2CH2OH)NCS2SnnBu2(Cl)] (2) and [(FcCH2)(CH2CH2OH)NCS2SnPh2(Cl)] (3) have been synthesized and characterized by elemental analysis, IR, UV-Vis, 1H, 13C and 119Sn NMR spectroscopy and X-ray crystallography. The crystal structure of 1 indicates that the coordination geometries around the tin(IV) center is intermediate between ideal trigonal-bipyramidal and square pyramidal coordination polyhedra bonded through two sulfur atoms of the dithiocarbamate ligand in an isobidentate mode, two CH3 groups and one chlorine atom. Since, in 2 and 3 only alkyl and aryl fragments have been changed we infer that both 2 and 3 would also have the same behaviors in the solution state as observed in 1. Ionic interactions abilities of 1-3 are examined in acetonitrile through UV-vis absorption spectroscopy which offers reasonably good selectivity and sensitivity towards the detection of the acetate ion. Compounds 1-3 exhibit a bathochromic shift with the acetate ion with a moderate association constant.

A sensitive chemiluminescent immunoassay to detect Chromotrope FB (Chr FB) in foods.

PubMed

Xu, Kun; Long, Hao; Xing, Rongge; Yin, Yongmei; Eremin, Sergei A; Meng, Meng; Xi, Rimo

2017-03-01

Chromotrope FB (Chr FB) is a synthetic azo dye permitted for use in foods and medicines. An acceptable daily intake (ADI) of Chr FB was 0-0.5mg/kg in China. In this study, we synthesized a Chr FB hapten with an amino group to prepare its artificial immunogen. Polyclonal antibodies obtained from New Zealand rabbits were applied to develop an indirect competitive chemiluminescent immunoassay (icCLIA) to detect Chr FB in foods. A horseradish peroxidase (HRP)-luminol-H 2 O 2 system was used to yield CL signal with p-iodophenol as an enhancement reagent. The method showed good specificity towards Chr FB and could detect as low as 0.02ngmL -1 Chr FB in buffer, 0.07ngg -1 in yoghurt candy, 0.07ngg -1 in vitamin drink and 0.13ngg -1 in bread. Compared with HPLC method, the proposed method is more sensitive by two orders of magnitude. The accuracy and precision of this method are acceptable and comparable with HPLC method. Therefore, the proposed method could be used for rapid screening of Chr FB in the mentioned foodstuffs. Copyright © 2016. Published by Elsevier B.V.

Determination of product branching ratio of the ClO self-reaction at 298 K

NASA Astrophysics Data System (ADS)

Horowitz, A.; Bauer, D.; Crowley, J. N.; Moortgat, G. K.

1993-07-01

The Cl2-sensitized continuous photolysis of O3 mixtures in O2 was investigated at 298 K using time resolved single wavelength and diode array spectroscopy to monitor the decay of O3 and the formation of OClO. Φ-O3 was found to be 4.1±0.4. This value, combined with the determination of the initial rates of OClO formation, allowed the evaluation of the following branching ratios into the three bimolecular disproportionation channels of ClO reactions; k3a/k3 = 0.40 ± 0.08, k3b/k3 = 0.42 ± 0.08 and k3c/k3 = 0.18 ± 0.02 where ClO + ClO → Cl2 + O2 (3a), ClO + ClO → Cl + Cl + O2 (3b) and ClO + ClO → Cl + OClO (3c).

CD8+ T cells stimulate Na-Cl co-transporter NCC in distal convoluted tubules leading to salt-sensitive hypertension

PubMed Central

Liu, Yunmeng; Rafferty, Tonya M.; Rhee, Sung W.; Webber, Jessica S.; Song, Li; Ko, Benjamin; Hoover, Robert S.; He, Beixiang; Mu, Shengyu

2017-01-01

Recent studies suggest a role for T lymphocytes in hypertension. However, whether T cells contribute to renal sodium retention and salt-sensitive hypertension is unknown. Here we demonstrate that T cells infiltrate into the kidney of salt-sensitive hypertensive animals. In particular, CD8+ T cells directly contact the distal convoluted tubule (DCT) in the kidneys of DOCA-salt mice and CD8+ T cell-injected mice, leading to up-regulation of the Na-Cl co-transporter NCC, p-NCC and the development of salt-sensitive hypertension. Co-culture with CD8+ T cells upregulates NCC in mouse DCT cells via ROS-induced activation of Src kinase, up-regulation of the K+ channel Kir4.1, and stimulation of the Cl− channel ClC-K. The last event increases chloride efflux, leading to compensatory chloride influx via NCC activation at the cost of increasing sodium retention. Collectively, these findings provide a mechanism for adaptive immunity involvement in the kidney defect in sodium handling and the pathogenesis of salt-sensitive hypertension. PMID:28067240

Simple chemiluminescence determination of ketotifen using tris(1,10 phenanthroline)ruthenium(II)- Ce(IV) system.

PubMed

Mokhtari, Ali; Ghazaeian, Mehrgan; Maghsoudi, Mahdieh; Keyvanfard, Mohsen; Emami, Iraj

2015-11-01

A new method using chemiluminescence (CL) detection has been developed for the simple determination of ketotifen fumarate (KF). The method is based on the catalytic effect of KF in the CL reaction of tris(1,10 phenanthroline)ruthenium(II), Ru(phen)3 (2+), with Ce(IV) in sulfuric acid medium. The CL response was detected using a lab-made chemiluminometer. Effects of chemical variables were investigated and under optimum conditions, the CL intensity was proportional to the concentration of the drug over the range 0.34-34.00 µg mL(-1) KF. The limit of detection (S/N=3) was 0.09 µg mL(-1). Effects of common ingredients were investigated and the method was applied successfully for determining KF in pharmaceutical formulations and human plasma. The percent of relative standard deviation (n=11) at level of 3.4 µg mL(-1) of KF was 4.6% and the minimum sampling rate was 70 samples per hour. The possible CL mechanism is proposed based on the kinetic characteristic of the CL reaction, CL spectrum, UV-Vis and phosphorescence spectra. Copyright © 2015 John Wiley & Sons, Ltd.

Study on the blocking effect of a quantum-dot TiO2 compact layer in dye-sensitized solar cells with ionic liquid electrolyte under low-intensity illumination

NASA Astrophysics Data System (ADS)

Zhai, Peng; Lee, Hyeonseok; Huang, Yu-Ting; Wei, Tzu-Chien; Feng, Shien-Ping

2016-10-01

In this study, ultrasmall and ultrafine TiO2 quantum dots (QDs) were prepared and used as a high-performance compact layer (CL) in dye-sensitized solar cells (DSCs). We systematically investigated the performance of TiO2 CL under both low-intensity light and indoor fluorescent light illumination and found that the efficiency of DSCs with the insertion of optimal TiO2 QDs-CL was increased up to 18.3% under indoor T5 fluorescent light illumination (7000 lux). We clarified the controversy over the blocking effect of TiO2 CL for the efficiency increment and confirmed that the TiO2 QDs-CL performed significantly better under low-intensity illumination due to the efficient suppression of electron recombination at the FTO/electrolyte interface. We, for the first time, demonstrate this potential for the application of the DSCs with TiO2 QDs-CL in the low-intensity light and indoor fluorescent light illumination.

Salt acclimation process: a comparison between a sensitive and a tolerant Olea europaea cultivar.

PubMed

Pandolfi, Camilla; Bazihizina, Nadia; Giordano, Cristiana; Mancuso, Stefano; Azzarello, Elisa

2017-03-01

Saline soils are highly heterogeneous in time and space, and this is a critical factor influencing plant physiology and productivity. Temporal changes in soil salinity can alter plant responses to salinity, and pre-treating plants with low NaCl concentrations has been found to substantially increase salt tolerance in different species in a process called acclimation. However, it still remains unclear whether this process is common to all plants or is only expressed in certain genotypes. We addressed this question by assessing the physiological changes to 100 mM NaCl in two contrasting olive cultivars (the salt-sensitive Leccino and the salt-tolerant Frantoio), following a 1-month acclimation period with 5 or 25 mM NaCl. The acclimation improved salt tolerance in both cultivars, but activated substantially different physiological adjustments in the tolerant and the sensitive cultivars. In the tolerant Frantoio the acclimation with 5 mM NaCl was more effective in increasing plant salt tolerance, with a 47% increase in total plant dry mass compared with non-acclimated saline plants. This enhanced biomass accumulation was associated with a 50% increase in K+ retention ability in roots. On the other hand, in the sensitive Leccino, although the acclimation process did not improve performance in terms of plant growth, pre-treatment with 5 and 25 mM NaCl substantially decreased salt-induced leaf cell ultrastructural changes, with leaf cell relatively similar to those of control plants. Taken together these results suggest that in the tolerant cultivar the acclimation took place primarily in the root tissues, while in the sensitive they occurred mainly at the shoot level. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

[Effects of different salt and alkali stresses on ion distribution in Red globe/Beta grapevines].

PubMed

Du, Yuan-peng; Jin, Xue-juan; Guo, Shu-hua; Fu, Qing-qing; Zhai, Heng

2015-06-01

The potted Red globe/Beta grapevines were selected to irrigated with NaCl, Na2SO4, NaHCO3, NH4Cl, (NH4)2SO4. Hence, the ions which induced leaf etiolation were screened and the impacts of different salt and alkali on ion distribution in different organs of grapevines were investigated. It was found that NaHCO3 exerted the greatest effects on grapevines, leaf etiolation at 14 days after treatment. By contrast, NaCl and NH4Cl treatments induced leaf etiolation at 28 days after treatment. The Na+ content in all the detected organs were significantly increased under NaHCO3 and NaCl treatment, and Na+ content in root under NaHCO3 treatment was 6.4 times as that in control root. NaHCO3 and NaCl treatments significantly decreased K+ content in the organs with the exception of leaf. NaHCO3 treatment significantly decreased K/Na in different organs, which declined to 0.1 in root. By contrast, NaCl treatment significantly decreased K/Na in the detected organs with exception of stem. Besides, the transport of Ca2+, Mg2+, Fe2+ to aboveground organs was significantly decreased by NaHCO3 and NaCl treatments. K/Na ratio in the detected organs were decreased under NH4Cl, (NH4) 2SO4 and Na2SO4 treatments, especially under NH4 Cl treatment. Taken together, NaHCO3 was the primary factor resulting in leaf etiolation, followed by NaCl and NH4Cl, while (NH4) 2SO4 and Na2SO4 produced impacts.

Preparation and Characterization of Nano-CL-20 Explosive

NASA Astrophysics Data System (ADS)

Bayat, Yadollah; Zeynali, Vida

2011-10-01

Nano-CL-20 was prepared via precipitative crystallization by spraying a solution of CL-20 in a solvent (ethyl acetate) into a nonsolvent (isooctane). Scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) were used to characterize the appearance and the size of the particles. The results revealed that nano-CL-20 particles have the shape of spheres or ellipsoids with an average size of 95 nm. Due to their small diameter and high surface energy, the particles tended to agglomerate. Impact sensitivity of nanosize CL-20 was decreased in comparison to micrometer-size CL-20.

A glassy carbon electrode modified with poly(2,4-dinitrophenylhydrazine) for simultaneous detection of dihydroxybenzene isomers.

PubMed

Lopa, Nasrin Siraj; Rahman, Md Mahbubur; Jang, Hohyoun; Sutradhar, Sabuj Chandra; Ahmed, Faiz; Ryu, Taewook; Kim, Whangi

2017-12-06

2,4-Dinitrophenylhydrazine (DNPH) was electropolymerized on the surface of an anodized glassy carbon electrode by cyclic voltammetry. The anodized electrode has a highly electroactive surface due to the creation of chemically functionalized graphitic nanoparticles, and this facilitates the formation of poly-DNPH via radical polymerization. Poly-DNPH displays excellent redox activity due to the presence of nitro groups on its backbone. These catalyze the electro-oxidation of hydroquinone (HQ) and catechol (CT). The peak-to-peak separation is around 109 mV, while a bare GCE cannot resolve the peaks (located at 165 and 274 mV vs. Ag/AgCl). Sensitivity is also enhanced to ∼1.20 and 1.19 μA·cm -2 ·μM -1 , respectively. The sensor has a linear response that covers the 20-250 μM concentration range for both HQ and CT, with 0.75 and 0.76 μM detection limits, respectively, at simultaneous detection. Commonly present species do not interfere. Graphical abstract A novel conducting poly(2,4-dinitrophenylhydrazine)-modified anodized glassy carbon electrode (pDNPH/AGCE) was developed by electrochemical method. The electro-catalytic activity of pDNPH/AGCE sensor was investigated for the selective and simultaneous electrochemical detection of hydroquinone (HQ) and catechol (CT), which revealed high sensitivities and low detection limits with excellent stability.

Quantitative detection of type A staphylococcal enterotoxin by Laurell electroimmunodiffusion.

PubMed

Gasper, E; Heimsch, R C; Anderson, A W

1973-03-01

The detection of staphylococcal enterotoxin A by the quantitative technique of electroimmunodiffusion is described. High dilutions of type-specific rabbit antiserum were used in 1% agarose gels, 1 mm thick, and prepared in 0.05-mug barbital buffer, pH 8.6. Volumes of 10 muliters containing 1.5 to 10 ng of toxin were electrophoresed out of 4-mm diameter wells at 5 mA/cm width of gel. The precipitin cones formed were made visible by first immersing the agarose gels in 0.2 M NaCl and then overlaying the surface with the purified globulin fraction of sheep serum against rabbit globulin, followed by soaking of the gels in 1% aqueous cadmium acetate and staining with 0.1% thiazine red in 1% glacial acetic acid. Fully extended cones, 4 to 23 mm in length depending on toxin concentration and antiserum dilution, were developed in 2 to 5 h of electrophoresis, and visualization was achieved within 2 to 3 h. Because the method is qualitative, quantitative, simple, rapid, and sensitive, it offers a practical tool for the detection of small amounts of bacterial toxins in contaminated foods. The method should also qualify as a sensitive detection device in biochemical procedures which attempt to trace, detect, and identify biological substances in nanogram quantities, provided these substances are antigenic and capable of forming a precipitate with their specific antibodies.

Enhancing and inhibiting effects of aromatic compounds on luminol-dimethylsulfoxide-OH(-) chemiluminescence and determination of intermediates in oxidative hair dyes by HPLC with chemiluminescence detection.

PubMed

Zhou, Jian; Xu, Hong; Wan, Guo-Hui; Duan, Chun-Feng; Cui, Hua

2004-10-08

The effect of 36 aromatic compounds on the luminol-dimethylsulfoxide-OH(-) chemiluminescence (CL) was systematically studied. It was found that dihydroxybenzenes, and ortho- and para-substituted aminophenols and phenylenediamines inhibited the CL and phenols with three or more than three hydroxyls except phloroglucin tended to enhance the CL. The CL inhibition and enhancement was proposed to be dependent on whether superoxide anion radical (O(2)(-)) was competitively consumed by compounds in the CL system. Trihydroxybenzenes were capable of generating superoxide anion radical, leading to the CL enhancement, whereas dihydroxybenzenes were superoxide anion radical scavenger, causing the CL inhibition. Based on the inhibited CL, a novel method for the simultaneous determination of p-phenylenediamine, o-phenylenediamine, p-aminophenol, o-aminophenol, resorcinol and hydroquinone by high-performance liquid chromatography coupled with chemiluminescence detection was developed. The method has been successfully applied to determine intermediates in oxidative hair dyes and wastewater of shampooing after hair dyed.

Highly sensitive derivatization reagents possessing positively charged structures for the determination of oligosaccharides in glycoproteins by high-performance liquid chromatography electrospray ionization tandem mass spectrometry.

PubMed

Min, Jun Zhe; Nagai, Keisuke; Shi, Qing; Zhou, Wenjun; Todoroki, Kenichiro; Inoue, Koichi; Lee, Yong-Ill; Toyo'oka, Toshimasa

2016-09-23

We have developed three kinds of novel derivatization reagents (4-CEBTPP, 4-CBBTPP, 5-COTPP) with triphenylphosphine (TPP) as a basic structure carrying a permanent positive charge for resolution of the oligosaccharides in glycoprotein using high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The synthesized reagents reacted with the sialylglycosylamine of the sialylglycopeptide after treatment by PNGase F. The final derivatives were analyzed by ESI-MS and sensitively detected in the selected reaction monitoring (SRM) mode. Furthermore, the limits of detection (S/N=3) on the SRM chromatograms were at the fmol level (30fmol). Therefore, we used the limit of detection of the reagent products detected by the SRM and evaluated the utility of each reagent. Among the reagents, the positively charged 4-CEBTPP derivative's peak area was the highest; 4-CEBTPP with a positively charged structure showed about a 20 times greater sensitivity for the glycosylamine of the SGP product compared to the conventional fluorescence reagent, Fmoc-Cl. In addition, various fragment ions based on the carbohydrate units also appeared in the MS/MS spectra. Among the fragment ions, m/z 627.37 (CE=40eV) corresponding to 4-CEBTPP-GlcNAc and m/z 120.09 (CE=100eV) corresponding to 4-CEBTPP are the most important ones for identifying the oligosaccharide. 4-CEBTPP-SGA was easily identified by the selected-ion chromatogram in the product ion scan (m/z 120.09) and in the precursor ion scan (m/z 627.37) by MS/MS detection. The derivatized analytes have a high ionization efficiency and they are detected with a high sensitivity in the electrospray ionization. The novel derivatization reagent with a multi-function provided a higher sensitivity for the oligosaccharide analysis, as well as a better specificity and feasibility. Furthermore, several oligosaccharides in fetuin and ribonuclease B were successfully identified by the proposed procedure. Copyright © 2016 Elsevier B.V. All rights reserved.

Differences in the sensitivity to Cu and ligand production of coastal vs offshore strains of Emiliania huxleyi.

PubMed

Echeveste, Pedro; Croot, Peter; von Dassow, Peter

2018-06-01

Copper is an essential trace metal for different physiological processes in phytoplankton, being either a limiting or toxic element depending on its bioavailability, which may induce local physiological adaptations. Atmospheric Cu deposition to the oceans can negatively impact phytoplankton growth, with the most Cu-sensitive phytoplankton exhibiting differences based on coastal vs oceanic origin. The goal of this work was to analyze sensitivity to Cu toxicity of the cosmopolitan marine calcifying phytoplankton, Emiliania huxleyi, exploring what factors determine intraspecific variability in sensitivity. We compared 17 strains isolated from coastal and open ocean waters of the Eastern South Pacific (ESP), the Mediterranean Sea, and the Tasman Sea. Offshore strains were as sensitive to Cu than coastal strains. Sensitivity to Cu was explained well by predicted depositional inputs of atmospheric Cu in the ESP both for coastal and offshore strains, but not when considered globally. The variability in Cu-sensitivity was also due to the production of organic Cu-ligands (CL), being the most productive strains the most tolerant to Cu at constitutive levels. When exposed to 100nM Cu, E. huxleyi produced significantly higher amounts of CL, especially coastal strains, but CL production did not correlate to observed EC50s. Copyright © 2017 Elsevier B.V. All rights reserved.

Detection of cephradine through the electrochemical study of the degradation product of cephradine

NASA Astrophysics Data System (ADS)

Jiang, Qingfeng; Ying, Yibin; Wang, Jianping; Ye, Zunzhong; Li, Yanbin

2005-11-01

The degradation product of cephradine(CEP), a broad spectrum antibiotic, with NaOH was studied in solution by Cyclic Voltammetry and Differential Pulse Voltammetry at a three electrode system (Gold working electrode, Hg/HgCl reference electrode and Platinum counter electrode). Our experiment was based on that the R-SH in degradation product could cause a deoxidization peak at gold working electrode. The response was optimized with respect to accumulation time, ionic strength, drug concentration, reproducibility and other variables. We found that the degradation product of CEP in Na2HPO4-NaH2PO4 buffer could cause a sensitive deoxidization peak at -0.68V. A linear dependence of peak currents on the concentration was observed in the range of 10-7 - 10-6 mol/L, with a detection limit of 0.5*10-7mol/L. This method can achieve satisfactory results in the application of detecting human-made CEP.

Kv3.4 is modulated by HIF-1α to protect SH-SY5Y cells against oxidative stress-induced neural cell death.

PubMed

Song, Min Seok; Ryu, Pan Dong; Lee, So Yeong

2017-05-18

The Kv3.4 channel is characterized by fast inactivation and sensitivity to oxidation. However, the physiological role of Kv3.4 as an oxidation-sensitive channel has yet to be investigated. Here, we demonstrate that Kv3.4 plays a pivotal role in oxidative stress-related neural cell damage as an oxidation-sensitive channel and that HIF-1α down-regulates Kv3.4 function, providing neuroprotection. MPP + and CoCl 2 are reactive oxygen species (ROS)-generating reagents that induce oxidative stress. However, only CoCl 2 decreases the expression and function of Kv3.4. HIF-1α, which accumulates in response to CoCl 2 treatment, is a key factor in Kv3.4 regulation. In particular, mitochondrial Kv3.4 was more sensitive to CoCl 2 . Blocking Kv3.4 function using BDS-II, a Kv3.4-specific inhibitor, protected SH-SY5Y cells against MPP + -induced neural cell death. Kv3.4 inhibition blocked MPP + -induced cytochrome c release from the mitochondrial intermembrane space to the cytosol and mitochondrial membrane potential depolarization, which are characteristic features of apoptosis. Our results highlight Kv3.4 as a possible new therapeutic paradigm for oxidative stress-related diseases, including Parkinson's disease.

Chemiluminescence as a condition monitoring method for thermal aging and lifetime prediction of an HTPB elastomer.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gillen, Kenneth Todd; Minier, Leanna M. G.; Celina, Mathias C.

Chemiluminescence (CL) has been applied as a condition monitoring technique to assess aging related changes in a hydroxyl-terminated-polybutadiene based polyurethane elastomer. Initial thermal aging of this polymer was conducted between 110 and 50 C. Two CL methods were applied to examine the degradative changes that had occurred in these aged samples: isothermal 'wear-out' experiments under oxygen yielding initial CL intensity and 'wear-out' time data, and temperature ramp experiments under inert conditions as a measure of previously accumulated hydroperoxides or other reactive species. The sensitivities of these CL features to prior aging exposure of the polymer were evaluated on the basismore » of qualifying this method as a quick screening technique for quantification of degradation levels. Both the techniques yielded data representing the aging trends in this material via correlation with mechanical property changes. Initial CL rates from the isothermal experiments are the most sensitive and suitable approach for documenting material changes during the early part of thermal aging.« less

NaCl intake and preference threshold of spontaneously hypertensive rats.

PubMed

Fregly, M J

1975-09-01

Both male and female spontaneously hypertensive (SH) rats have an appetite for NaCl solution. The appetite is present when a choice is offered between distilled water and either isotonic or hypertonic (0.25 M) NaCl solution to drink. Total fluid intake (water plus NaCl solution) was greater for SH rats than for controls while food intakes (g/100 g body wt/day) of SH rats were not different from controls. Mean body weight of SH rats was always less than that of controls. The appetite for NaCl solution was accompanied by a significant reduction in preference (detection) threshold. SH rats could detect the difference between distilled water and NaCl solution when the concentration of the latter was 12 mEq/liter compared to a control threshold of 30 mEq/liter. The NaCl appetite and reduced NaCl preference threshold induced by spontaneous hypertension is in marked contrast to the NaCl aversion induced by other types of experimentally induced hypertension in rats. The mechanism or mechanisms responsible for these differences remain for further study.

Three-Dimensional Porous Nickel Frameworks Anchored with Cross-Linked Ni(OH)2 Nanosheets as a Highly Sensitive Nonenzymatic Glucose Sensor.

PubMed

Mao, Weiwei; He, Haiping; Sun, Pengcheng; Ye, Zhizhen; Huang, Jingyun

2018-05-02

A facile and scalable in situ microelectrolysis nanofabrication technique is developed for preparing cross-linked Ni(OH) 2 nanosheets on a novel three-dimensional porous nickel template (Ni(OH) 2 @3DPN). For the constructed template, the porogen of NaCl particles not only induces a self-limiting surficial hot corrosion to claim the "start engine stop" mechanism but also serves as the primary battery electrolyte to greatly accelerate the growth of Ni(OH) 2 . As far as we know, the microelectrolysis nanofabrication is superior to the other reported Ni(OH) 2 synthesis methods due to the mild condition (60 °C, 6 h, NaCl solution, ambient environment) and without any post-treatment. The integrated Ni(OH) 2 @3DPN electrode with a highly suitable microstructure and a porous architecture implies a potential application in electrochemistry. As a proof-of-concept demonstration, the electrode was employed for nonenzymatic glucose sensing, which exhibits an outstanding sensitivity of 2761.6 μA mM -1 cm -2 ranging from 0.46 to 2100 μM, a fast response, and a low detection limit. The microelectrolysis nanofabrication is a one-step, binder-free, entirely green, and therefore it has a distinct advantage to improve clean production and reduce energy consumption.

Furosemide- and bumetanide-sensitive ion transport and volume control in primary astrocyte cultures from rat brain.

PubMed

Kimelberg, H K; Frangakis, M V

1985-12-30

K+ and Cl- transport using 42K+ and 36Cl- was studied in primary astrocyte cultures prepared from neonatal rat brains. A component of 42K+ uptake was sensitive to both furosemide and bumetanide with maximum inhibition being obtained at 1 and 0.01 mM concentrations of the inhibitors, respectively. Furosemide and bumetanide also markedly inhibited uptake of 36Cl-. 42K+ uptake in the presence of ouabain was also sensitive to the omission of medium Na+ and Cl-. These results suggest the existence of a K+ + Na+ + Cl- cotransport system in astrocyte cultures which in many cells has been shown to be involved in volume regulation. We studied volume changes using uptake of [14C]3-O- methyl-D-glucose ([14C]3-OMG), and also ion transport, in attached cells in response to exposure to hyper- or hypotonic medium. Exposure to medium made hypertonic with mannitol resulted in shrinkage of the [14C]3-OMG space of the cells, but did not affect 36Cl- content, expressed as nmol/mg protein. Exposure to hypotonic medium led to a marked increase in the [14C]3-OMG space, rapidly followed by a decrease towards control values. After the cells were then exposed to isotonic medium there was an immediate decrease followed by a slower increase in the [14C]3-OMG space. The increase in the [14C]3-OMG space was partially inhibited by 1 mM furosemide.(ABSTRACT TRUNCATED AT 250 WORDS)

Inorganic and organic mercury chloride toxicity to Coturnix: Sensitivity related to age and quantal assessment of physiologic responses

USGS Publications Warehouse

Hill, E.F.

1982-01-01

The toxicities of mercuric chloride (HgCl(,2)) and methylmercuric chloride (CH(,3)HgCl) were compared for coturnix (Coturnix coturnix japonica) from hatching to adulthood. Comparisons were based on: (1) Median lethal dosages (LD50) derived by administering single peroral and single intramuscular dosages of mercury, (2) median lethal concentrations (LC50) derived by feeding mercury for 5 days, (3) median toxic concentrations (TC50) derived by feeding mercury 9 weeks and measuring plasma enzyme activity, plasma electrolytes, and other blood constituents, and (4) transient changes of various blood chemistries following a single peroral dose of mercury. Acute peroral and intramuscular LD50s for HgCl(,2) and CH(,3)HgCl increased by two- to threefold for coturnix chicks from hatching to 4 weeks of age. Concomitantly, the LC50s also increased, but the important difference between test procedures was that with both single dose routes of exposure the toxicity ratios, i.e., HgCl(,2)/CH(,3)HgCl, at each age were about 2 to 2.5 compared to about 100 for the LC50s. For example, at 2 weeks of age the peroral LD50s for HgCl(,2) and CH(,3)HgCl were 42 and 18 mg/kg; the dietary LC50s were 5086 and 47 ppm for HgCl(,2) and CH(,3)HgCl. The 9 week feeding trial was not associated with gross effects from either HgCl(,2) at 0.5 to 32 ppm or CH(,3)HgCl at 0.125 to 8 ppm. However, subtle responses were detected for the plasma enzymes aspartate aminotransferase, lactate dehydrogenase, and ornithine carbamoyl transferase and could be quantified by probit analysis. This quantal procedure was based on establishment of a normal value for each enzyme and classing outliers as respondents. A 'hazard index' based on the TC50 for an enzyme divided by the LD50 or LC50 was introduced. The single oral dosages of HgCl(,2) and CH(,3)HgCl showed that ratios of alanine aminotransferase, lactate dehydrogenase, and orinthine carbamoyl transferase for the liver and kidneys of adult coturnix were opposite from that accepted for mammals. It was concluded that a chronic study of sublethal responses of young birds should be required in addition to the current toxicity screens used for regulatory purposes.

Inorganic and organic mercury chloride toxicity to Coturnix: sensitivity related to age and quantal assessment of physiologic responses

USGS Publications Warehouse

Hill, E.F.

1981-01-01

The toxicities of mercuric chloride (HgCl(,2)) and methylmercuric chloride (CH(,3)HgCl) were compared for coturnix (Coturnix coturnix japonica) from hatching to adulthood. Comparisons were based on: (1) Median lethal dosages (LD50) derived by administering single peroral and single intramuscular dosages of mercury, (2) median lethal concentrations (LC50) derived by feeding mercury for 5 days, (3) median toxic concentrations (TC50) derived by feeding mercury 9 weeks and measuring plasma enzyme activity, plasma electrolytes, and other blood constituents, and (4) transient changes of various blood chemistries following a single peroral dose of mercury. Acute peroral and intramuscular LD50s for HgCl(,2) and CH(,3)HgCl increased by two- to threefold for coturnix chicks from hatching to 4 weeks of age. Concomitantly, the LC50s also increased, but the important difference between test procedures was that with both single dose routes of exposure the toxicity ratios, i.e., HgCl(,2)/CH(,3)HgCl, at each age were about 2 to 2.5 compared to about 100 for the LC50s. For example, at 2 weeks of age the peroral LD50s for HgCl(,2) and CH(,3)HgCl were 42 and 18 mg/kg; the dietary LC50s were 5086 and 47 ppm for HgCl(,2) and CH(,3)HgCl. The 9 week feeding trial was not associated with gross effects from either HgCl(,2) at 0.5 to 32 ppm or CH(,3)HgCl at 0.125 to 8 ppm. However, subtle responses were detected for the plasma enzymes aspartate aminotransferase, lactate dehydrogenase, and ornithine carbamoyl transferase and could be quantified by probit analysis. This quantal procedure was based on establishment of a normal value for each enzyme and classing outliers as respondents. A 'hazard index' based on the TC50 for an enzyme divided by the LD50 or LC50 was introduced. The single oral dosages of HgCl(,2) and CH(,3)HgCl showed that ratios of alanine aminotransferase, lactate dehydrogenase, and orinthine carbamoyl transferase for the liver and kidneys of adult coturnix were opposite from that accepted for mammals. It was concluded that a chronic study of sublethal responses of young birds should be required in addition to the current toxicity screens used for regulatory purposes.

The Use of Neutron Analysis Techniques for Detecting The Concentration And Distribution of Chloride Ions in Archaeological Iron

PubMed Central

Watkinson, D; Rimmer, M; Kasztovszky, Z; Kis, Z; Maróti, B; Szentmiklósi, L

2014-01-01

Chloride (Cl) ions diffuse into iron objects during burial and drive corrosion after excavation. Located under corrosion layers, Cl is inaccessible to many analytical techniques. Neutron analysis offers non-destructive avenues for determining Cl content and distribution in objects. A pilot study used prompt gamma activation analysis (PGAA) and prompt gamma activation imaging (PGAI) to analyse the bulk concentration and longitudinal distribution of Cl in archaeological iron objects. This correlated with the object corrosion rate measured by oxygen consumption, and compared well with Cl measurement using a specific ion meter. High-Cl areas were linked with visible damage to the corrosion layers and attack of the iron core. Neutron techniques have significant advantages in the analysis of archaeological metals, including penetration depth and low detection limits. PMID:26028670

Chlorine-36 in seawater

NASA Astrophysics Data System (ADS)

Argento, David C.; Stone, John O.; Keith Fifield, L.; Tims, Stephen G.

2010-04-01

Natural cosmogenic 36Cl found in seawater originates from spallation of atmospheric 40Ar, capture of secondary cosmic-ray neutrons by dissolved 35Cl, and river runoff which contains 36Cl produced in situ over the surface of the continents. The long residence time of chloride in the ocean and long half-life of 36Cl compared to the oceanic mixing time should result in a homogenous 36Cl/Cl ratio throughout the ocean. Production by neutron capture in the course of nuclear weapons testing should be insignificant averaged over the oceans as a whole, but may have led to regions of elevated 36Cl concentration. Previous attempts to measure the 36Cl/Cl ratio of seawater have been hindered by interferences, contamination, or insufficient analytic sensitivity. Here we report preliminary measurements on seawater samples, which demonstrate that the 36Cl/Cl ratio is 0.5 ± 0.3 × 10 -15, in reasonable agreement with calculated contributions from the sources listed above.

Dye sensitized photoelectrochemical immunosensor for the tumor marker CEA by using a flower-like 3D architecture prepared from graphene oxide and MoS2.

PubMed

Song, Kaijing; Ding, Chuanmin; Zhang, Bing; Chang, Honghong; Zhao, Zhihuan; Wei, Wenlong; Wang, Junwen

2018-06-01

The authors describe a dye-sensitized photoelectrochemical immunoassay for the tumor marker carcinoembryonic antigen (CEA). The method employs the rhodamine dye Rh123 with red color and absorption maximum at 500 nm for spectral sensitization, and a 3D nanocomposite prepared from graphene oxide and MoS 2 acting as the photoelectric conversion layer. The nanocomposite with flower-like 3D architectures was characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, and UV-vis diffuse reflectometry. A photoelectrochemical sandwich immunoassay was developed that is based on the use of the nanocomposite and based on the specific binding of antibody and antigen, and by using a secondary antibody labeled with Rh123 and CdS (Ab 2 -Rh123@CdS). Under optimal conditions and at a typical working voltage of 0 V (vs. Hg/HgCl 2 ), the photocurrent increases linearly 10 pg mL -1 to 80 ng mL -1 CEA concentration range, with a 3.2 pg mL -1 detection limit. Graphical abstract Flower-like GO-MoS 2 complex with high efficiency of electron transport was synthesized to construct photoelectrochemical platform. The sandwich-type immunoassay was built on this platform based on specific binding of antigen and antibody. Carcinoembryonic antigen in sample was detected sensitively by using sensitization of rhodamine dye Rh123 as signal amplification strategy.

Biochemical changes in sweat following prolonged ischemia.

PubMed

Ferguson-Pell, M; Hagisawa, S

1988-01-01

Much emphasis has been placed on the measurement of physical parameters at the body support interface in order to detect and moderate conditions which could result in pressure damage to soft tissues. Major difficulties are encountered both in the design of instrumentation and interpretation of the data collected. Metabolic processes in sweat glands that control sweat secretion have been shown to be sensitive to applied pressure, producing sweating rate suppression and changes in sweat NaCl concentration. In this study, we have demonstrated the feasibility of measuring lactate concentration in sweat collected locally using an electrochemical stimulation technique (iontophoresis of pilocarpine nitrate). Elevated levels of sweat lactate concentration during local tissue indentation were detected in a group of able-bodied subjects. Upon removal of the indentor, however, levels of sweat lactate returned to normal.

Measurement of intracellular chloride in guinea-pig vas deferens by ion analysis, 36chloride and micro-electrodes

PubMed Central

Aickin, C. Claire; Brading, Alison F.

1982-01-01

1. Cl-sensitive micro-electrodes were used to measure the intracellular Cl activity (aCli) in smooth muscle cells of the guinea-pig vas deferens. The values obtained were compared with those of intracellular Cl (Cli) found by both ion analysis and 36Cl efflux. 2. Various combinations of filling solution for recording membrane potential (Em), and type of micro-electrode were tested. The most successful, which allowed continuous recording of aCli for several hours, was a double-barrelled electrode using the reference liquid ion exchanger (RLIE; Thomas & Cohen, 1981). However, aCli measured both by simultaneous impalements of separate cells with Cl-sensitive and conventional micro-electrodes, and by double-barrelled micro-electrodes, was about 42 mM in normal Krebs solution. This is five times higher than the value from a passive distribution. ECl was about -24 mV, more than 40 mV positive to Em. 3. On complete removal of extracellular Cl (Clo), aCli fell to an apparent level of about 3 mM. If this represents interference from other anions, the maximum error in ECl measured in normal Krebs solution is 2·5 mV. Replacement of Clo caused a rapid increase in aCli. This must be caused by an active transport of Cl- ions into the cell against their electrochemical gradient. 4. The stabilized values of aCli measured at different levels of Clo agree surprisingly well with aCli estimated from ion analysis and 36Cl efflux, assuming that the intracellular activity coefficient was the same as measured in the normal Krebs solution. The relationship of aCli to Clo was hyperbolic. 5. It is concluded that Cl-sensitive micro-electrodes accurately measure aCli in smooth muscle cells. The remarkable agreement between the direct and indirect methods of measuring Cli suggests that Cl- ions are not bound to a significant extent and that the compartment seen by the micro-electrodes is probably representative of the whole cell. PMID:7108787

An Electrochemical DNA Sensing System Using Modified Nanoparticle Probes for Detecting Methicillin-Resistant Staphylococcus aureus.

PubMed

Sakamoto, Hiroaki; Amano, Yoshihisa; Satomura, Takenori; Suye, Shin-Ichiro

2017-01-01

We have developed a novel, highly sensitive, biosensing system for detecting methicillin-resistant Staphylococcus aureus (MRSA). The system employs gold nanoparticles (AuNPs), magnetic nanoparticles (mNPs), and an electrochemical detection method. We have designed and synthesized ferrocene- and single-stranded DNA-conjugated nanoparticles that hybridize to MRSA DNA. Hybridized complexes are easily separated by taking advantage of mNPs. A current response could be obtained through the oxidation of ferrocene on the AuNP surface when a constant potential of +250 mV vs. Ag/AgCl is applied. The enzymatic reaction of L-proline dehydrogenase provides high signal amplification. This sensing system, using a nanoparticle-modified probe, has the ability to detect 10 pM of genomic DNA from MRSA without amplification by the polymerase chain reaction. Current responses are linearly related to the amount of genomic DNA in the range of 10-166 pM. Selectivity is confirmed by demonstrating that this sensing system could distinguish MRSA from Staphylococcus aureus (SA) DNA.

Easy methods to study the smart energetic TNT/CL-20 co-crystal.

PubMed

Li, Huarong; Shu, Yuanjie; Gao, Shijie; Chen, Ling; Ma, Qing; Ju, Xuehai

2013-11-01

2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) is a high-energy nitramine explosive with high mechanical sensitivity. 2,4,6-trinitrotoluene (TNT) is insensitive but by no means a high performance explosive. To reveal the significant importance and smart-material functionality of the energetic-energetic co-crystals, the stability, mechanical and explosive properties TNT/CL-20 co-crystal, TNT crystal and CL-20 crystal were studied. Non-hydrogen bonded non-covalent interactions govern the structures of energetic-energetic co-crystals. However, it is very difficult to accurately calculate the non-covalent intermolecular interaction energies. In this paper, the local conformation and the intricate non-covalent interactions were effectively mapped and analyzed from the electron density (ρ) and its derivatives. The results show that the two components TNT and CL-20 are connected mainly by nitro-aromatic interactions, and nitro-nitro interactions. The steric interactions in TNT/CL-20 could not be confronted with the attractive interactions. Moreover, the scatter graph of TNT crystal reveals the reason why TNT is brittle. The detailed electrostatic potential analysis predicted that the detonation velocities (D) and impact sensitivity for the compounds both increase in the sequence of CL-20 > TNT/CL-20 co-crystal > TNT. Additionally, TNT/CL-20 co-crystal has better malleability than its pure components. This demonstrates the capacity and the feasibility of realizing explosive smart materials by co-crystallization, even if strong hydrogen bonding schemes are generally lacking in energetic materials.

Functional and molecular characterization of transmembrane intracellular pH regulators in human dental pulp stem cells.

PubMed

Chen, Gunng-Shinng; Lee, Shiao-Pieng; Huang, Shu-Fu; Chao, Shih-Chi; Chang, Chung-Yi; Wu, Gwo-Jang; Li, Chung-Hsing; Loh, Shih-Hurng

2018-06-01

Homeostasis of intracellular pH (pH i ) plays vital roles in many cell functions, such as proliferation, apoptosis, differentiation and metastasis. Thus far, Na + -H + exchanger (NHE), Na + -HCO 3 - co-transporter (NBC), Cl - /HCO 3 - exchanger (AE) and Cl - /OH - exchanger (CHE) have been identified to co-regulate pH i homeostasis. However, functional and biological pH i -regulators in human dental pulp stem cells (hDPSCs) have yet to be identified. Microspectrofluorimetry technique with pH-sensitive fluorescent dye, BCECF, was used to detect pH i changes. NH 4 Cl and Na + -acetate pre-pulse were used to induce intracellular acidosis and alkalosis, respectively. Isoforms of pH i -regulators were detected by Western blot technique. The resting pH i was no significant difference between that in HEPES-buffered (nominal HCO 3 - -free) solution or CO 2 /HCO 3 -buffered system (7.42 and 7.46, respectively). The pH i recovery following the induced-intracellular acidosis was blocked completely by removing [Na + ] o , while only slowed (-63%) by adding HOE694 (a NHE1 specific inhibitor) in HEPES-buffered solution. The pH i recovery was inhibited entirely by removing [Na + ] o , while adding HOE 694 pulse DIDS (an anion-transporter inhibitor) only slowed (-55%) the acid extrusion. Both in HEPES-buffered and CO 2 /HCO 3 -buffered system solution, the pH i recovery after induced-intracellular alkalosis was entirely blocked by removing [Cl - ] o . Western blot analysis showed the isoforms of pH i regulators, including NHE1/2, NBCe1/n1, AE1/2/3/4 and CHE in the hDPSCs. We demonstrate for the first time that resting pH i is significantly higher than 7.2 and meditates functionally by two Na + -dependent acid extruders (NHE and NBC), two Cl - -dependent acid loaders (CHE and AE) and one Na + -independent acid extruder(s) in hDPSCs. These findings provide novel insight for basic and clinical treatment of dentistry. Copyright © 2018 Elsevier Ltd. All rights reserved.

Manganese-Enhanced Magnetic Resonance Imaging and Studies of Rat Behavior: Transient Motor Deficit in Skilled Reaching, Rears, and Activity in Rats After a Single Dose of MnCl2.

PubMed

Alaverdashvili, Mariam; Lapointe, Valerie; Whishaw, Ian Q; Cross, Albert R

2017-01-01

Manganese-enhanced magnetic resonance imaging (MEMRI) has been suggested to be a useful tool to visualize and map behavior-relevant neural populations at large scale in freely behaving rodents. A primary concern in MEMRI applications is Mn 2+ toxicity. Although a few studies have specifically examined toxicity on gross motor behavior, Mn 2+ toxicity on skilled motor behavior was not explored. Thus, the objective of this study was to combine manganese as a functional contrast agent with comprehensive behavior evaluation. We evaluated Mn 2+ effect on skilled reach-to-eat action, locomotion, and balance using a single pellet reaching task, activity cage, and cylinder test, respectively. The tests used are sensitive to the pathophysiology of many neurological and neurodegenerative disorders of the motor system. The behavioral testing was done in combination with a moderate dose of manganese. Behavior was studied before and after a single, intravenous infusion of MnCl 2 (48 mg/kg). The rats were imaged at 1, 3, 5, 7, and 14 days following infusion. The results show that MnCl 2 infusion resulted in detectable abnormalities in skilled reaching, locomotion, and balance that recovered within 3 days compared with the infusion of saline. Because some tests and behavioral measures could not detect motor abnormalities of skilled movements, comprehensive evaluation of motor behavior is critical in assessing the effects of MnCl 2 . The relaxation mapping results suggest that the transport of Mn 2+ into the brain is through the choroid plexus-cerebrospinal fluid system with the primary entry point and highest relaxation rates found in the pituitary gland. Relaxation rates in the pituitary gland correlated with measures of motor skill, suggesting that altered motor ability is related to the level of Mn circulating in the brain. Thus, combined MEMRI and behavioral studies that both achieve adequate image enhancement and are also free of motor skills deficits are difficult to achieve using a single systemic dose of MnCl 2 .

Improved Bi Film Wrapped Single Walled Carbon Nanotubes for Ultrasensitive Electrochemical Detection of Trace Cr(VI).

PubMed

Ouyang, Ruizhuo; Zhang, Wangyao; Zhou, Shilin; Xue, Zi-Ling; Xu, Lina; Gu, Yingying; Miao, Yuqing

2013-12-15

We report here the successful fabrication of an improved Bi film wrapped single walled carbon nanotubes modified glassy carbon electrode (Bi/SWNTs/GCE) as a highly sensitive platform for ultratrace Cr(VI) detection through catalytic adsorptive cathodic stripping voltammetry (AdCSV). The introduction of negatively charged SWNTs extraordinarily decreased the size of Bi particles to nanoscale due to electrostatic interaction which made Bi(III) cations easily attracted onto the surface of SWNTs in good order, leading to higher quality of Bi film deposition. The obtained Bi/SWNTs composite was well characterized with electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), the static water contact angle and the voltammetric measurements. The results demonstrates the improvements in the quality of Bi film deposited on the surface of SWNTs such as faster speed of electron transfer, more uniform and smoother morphology, better hydrophilicity and higher stripping signal. Using diethylene triaminepentaacetic acid (DTPA) as complexing ligand, the fabricated electrode displays a well-defined and highly sensitive peak for the reduction of Cr(III)-DTPA complex at -1.06 V ( vs . Ag/AgCl) with a linear concentration range of 0-25 nM and a fairly low detection limit of 0.036 nM. No interference was found in the presence of coexisting ions, and good recoveries were achieved for the analysis of a river sample. In comparison to previous approaches using Bi film modified GCE, the newly designed electrode exhibits better reproducibility and repeatability towards aqueous detection of trace Cr(VI) and appears to be very promising as the basis of a highly sensitive and selective voltammetric procedure for Cr(VI) detection at trace level in real samples.

Improved Bi Film Wrapped Single Walled Carbon Nanotubes for Ultrasensitive Electrochemical Detection of Trace Cr(VI)

PubMed Central

Zhou, Shilin; Xue, Zi-Ling; Xu, Lina; Gu, Yingying; Miao, Yuqing

2014-01-01

We report here the successful fabrication of an improved Bi film wrapped single walled carbon nanotubes modified glassy carbon electrode (Bi/SWNTs/GCE) as a highly sensitive platform for ultratrace Cr(VI) detection through catalytic adsorptive cathodic stripping voltammetry (AdCSV). The introduction of negatively charged SWNTs extraordinarily decreased the size of Bi particles to nanoscale due to electrostatic interaction which made Bi(III) cations easily attracted onto the surface of SWNTs in good order, leading to higher quality of Bi film deposition. The obtained Bi/SWNTs composite was well characterized with electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), the static water contact angle and the voltammetric measurements. The results demonstrates the improvements in the quality of Bi film deposited on the surface of SWNTs such as faster speed of electron transfer, more uniform and smoother morphology, better hydrophilicity and higher stripping signal. Using diethylene triaminepentaacetic acid (DTPA) as complexing ligand, the fabricated electrode displays a well-defined and highly sensitive peak for the reduction of Cr(III)-DTPA complex at −1.06 V (vs. Ag/AgCl) with a linear concentration range of 0–25 nM and a fairly low detection limit of 0.036 nM. No interference was found in the presence of coexisting ions, and good recoveries were achieved for the analysis of a river sample. In comparison to previous approaches using Bi film modified GCE, the newly designed electrode exhibits better reproducibility and repeatability towards aqueous detection of trace Cr(VI) and appears to be very promising as the basis of a highly sensitive and selective voltammetric procedure for Cr(VI) detection at trace level in real samples. PMID:24771881

LabVIEW-based control and data acquisition system for cathodoluminescence experiments.

PubMed

Bok, J; Schauer, P

2011-11-01

Computer automation of cathodoluminescence (CL) experiments using equipment developed in our laboratory is described. The equipment provides various experiments for CL efficiency, CL spectra, and CL time response studies. The automation was realized utilizing the graphical programming environment LabVIEW. The developed application software with procedures for equipment control and data acquisition during various CL experiments is presented. As the measured CL data are distorted by technical limitations of the equipment, such as equipment spectral sensitivity and time response, data correction algorithms were incorporated into the procedures. Some examples of measured data corrections are presented. © 2011 American Institute of Physics

Notes From the Field: Secondary Task Precision for Cognitive Load Estimation During Virtual Reality Surgical Simulation Training.

PubMed

Rasmussen, Sebastian R; Konge, Lars; Mikkelsen, Peter T; Sørensen, Mads S; Andersen, Steven A W

2016-03-01

Cognitive load (CL) theory suggests that working memory can be overloaded in complex learning tasks such as surgical technical skills training, which can impair learning. Valid and feasible methods for estimating the CL in specific learning contexts are necessary before the efficacy of CL-lowering instructional interventions can be established. This study aims to explore secondary task precision for the estimation of CL in virtual reality (VR) surgical simulation and also investigate the effects of CL-modifying factors such as simulator-integrated tutoring and repeated practice. Twenty-four participants were randomized for visual assistance by a simulator-integrated tutor function during the first 5 of 12 repeated mastoidectomy procedures on a VR temporal bone simulator. Secondary task precision was found to be significantly lower during simulation compared with nonsimulation baseline, p < .001. Contrary to expectations, simulator-integrated tutoring and repeated practice did not have an impact on secondary task precision. This finding suggests that even though considerable changes in CL are reflected in secondary task precision, it lacks sensitivity. In contrast, secondary task reaction time could be more sensitive, but requires substantial postprocessing of data. Therefore, future studies on the effect of CL modifying interventions should weigh the pros and cons of the various secondary task measurements. © The Author(s) 2015.

Reduce the Sensitivity of CL-20 by Improving Thermal Conductivity Through Carbon Nanomaterials.

PubMed

Wang, Shuang; An, Chongwei; Wang, Jingyu; Ye, Baoyun

2018-03-27

The graphene (rGO) and carbon nanotube (CNT) were adopted to enhance the thermal conductivity of CL-20-based composites as conductive fillers. The microstructure features were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD), and tested the properties by differential scanning calorimeter (DSC), static electricity accumulation, special height, thermal conductivity, and detonation velocity. The results showed that the mixture of rGO and CNT had better effect in thermal conductivity than rGO or CNT alone under the same loading (1 wt%) and it formed a three-dimensional heat-conducting network structure to improve the heat property of the system. Besides, the linear fit proved that the thermal conductivity of the CL-20-based composites were negatively correlated with the impact sensitivity, which also explained that the impact sensitivity was significantly reduced after the thermal conductivity increased and the explosive still maintained better energy.

Reduce the Sensitivity of CL-20 by Improving Thermal Conductivity Through Carbon Nanomaterials

NASA Astrophysics Data System (ADS)

Wang, Shuang; An, Chongwei; Wang, Jingyu; Ye, Baoyun

2018-03-01

The graphene (rGO) and carbon nanotube (CNT) were adopted to enhance the thermal conductivity of CL-20-based composites as conductive fillers. The microstructure features were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD), and tested the properties by differential scanning calorimeter (DSC), static electricity accumulation, special height, thermal conductivity, and detonation velocity. The results showed that the mixture of rGO and CNT had better effect in thermal conductivity than rGO or CNT alone under the same loading (1 wt%) and it formed a three-dimensional heat-conducting network structure to improve the heat property of the system. Besides, the linear fit proved that the thermal conductivity of the CL-20-based composites were negatively correlated with the impact sensitivity, which also explained that the impact sensitivity was significantly reduced after the thermal conductivity increased and the explosive still maintained better energy.

An L319F mutation in transmembrane region 3 (TM3) selectively reduces sensitivity to okaramine B of the Bombyx mori l-glutamate-gated chloride channel.

PubMed

Furutani, Shogo; Okuhara, Daiki; Hashimoto, Anju; Ihara, Makoto; Kai, Kenji; Hayashi, Hideo; Sattelle, David B; Matsuda, Kazuhiko

2017-10-01

Okaramines produced by Penicillium simplicissimum AK-40 activate l-glutamate-gated chloride channels (GluCls) and thus paralyze insects. However, the okaramine binding site on insect GluCls is poorly understood. Sequence alignment shows that the equivalent of residue Leucine319 of the okaramine B sensitive Bombyx mori (B. mori) GluCl is a phenylalanine in the okaramine B insensitive B. mori γ-aminobutyric acid-gated chloride channel of the same species. This residue is located in the third transmembrane (TM3) region, a location which in a nematode GluCl is close to the ivermectin binding site. The B. mori GluCl containing the L319F mutation retained its sensitivity to l-glutamate, but responses to ivermectin were reduced and those to okaramine B were completely blocked.

Issues in Stratospheric Ozone Depletion.

NASA Astrophysics Data System (ADS)

Lloyd, Steven Andrew

Following the announcement of the discovery of the Antarctic ozone hole in 1985 there have arisen a multitude of questions pertaining to the nature and consequences of polar ozone depletion. This thesis addresses several of these specific questions, using both computer models of chemical kinetics and the Earth's radiation field as well as laboratory kinetic experiments. A coupled chemical kinetic-radiative numerical model was developed to assist in the analysis of in situ field measurements of several radical and neutral species in the polar and mid-latitude lower stratosphere. Modeling was used in the analysis of enhanced polar ClO, mid-latitude diurnal variation of ClO, and simultaneous measurements of OH, HO_2, H_2 O and O_3. Most importantly, such modeling was instrumental in establishing the link between the observed ClO and BrO concentrations in the Antarctic polar vortex and the observed rate of ozone depletion. The principal medical concern of stratospheric ozone depletion is that ozone loss will lead to the enhancement of ground-level UV-B radiation. Global ozone climatology (40^circS to 50^ circN latitude) was incorporated into a radiation field model to calculate the biologically accumulated dosage (BAD) of UV-B radiation, integrated over days, months, and years. The slope of the annual BAD as a function of latitude was found to correspond to epidemiological data for non-melanoma skin cancers for 30^circ -50^circN. Various ozone loss scenarios were investigated. It was found that a small ozone loss in the tropics can provide as much additional biologically effective UV-B as a much larger ozone loss at higher latitudes. Also, for ozone depletions of > 5%, the BAD of UV-B increases exponentially with decreasing ozone levels. An important key player in determining whether polar ozone depletion can propagate into the populated mid-latitudes is chlorine nitrate, ClONO_2 . As yet this molecule is only indirectly accounted for in computer models and field measurements. Therefore a laboratory prototype of an instrument to measure ClONO _2 concentrations in situ was developed, adapting techniques recently developed in this research group to measure ClO concentrations at the part-per-trillion level. The detection scheme involves heating a flowing air sample to almost 500K, thermally dissociating ClONO _2 into ClO and NO_2 , and measuring the resulting ClO concentration by titrating with NO to produce Cl atoms, which are detected by resonance fluoresence. The calibration of this technique is very sensitive to flow parameters (temperature, pressure, flow velocity, added NO concentration, and homogeneity of flow). The issues developed in this thesis contribute to our understanding of the mechanisms of stratospheric ozone depletion and its potential global impact. It is becoming increasingly apparent that our ability to predict the future course of global ozone depletion is critically dependent on our ability to reproduce in situ and remote measurements with numerical models.

Recommendations for processing atmospheric attenuated backscatter profiles from Vaisala CL31 ceilometers

NASA Astrophysics Data System (ADS)

Kotthaus, Simone; O'Connor, Ewan; Münkel, Christoph; Charlton-Perez, Cristina; Haeffelin, Martial; Gabey, Andrew M.; Grimmond, C. Sue B.

2016-08-01

Ceilometer lidars are used for cloud base height detection, to probe aerosol layers in the atmosphere (e.g. detection of elevated layers of Saharan dust or volcanic ash), and to examine boundary layer dynamics. Sensor optics and acquisition algorithms can strongly influence the observed attenuated backscatter profiles; therefore, physical interpretation of the profiles requires careful application of corrections. This study addresses the widely deployed Vaisala CL31 ceilometer. Attenuated backscatter profiles are studied to evaluate the impact of both the hardware generation and firmware version. In response to this work and discussion within the CL31/TOPROF user community (TOPROF, European COST Action aiming to harmonise ground-based remote sensing networks across Europe), Vaisala released new firmware (versions 1.72 and 2.03) for the CL31 sensors. These firmware versions are tested against previous versions, showing that several artificial features introduced by the data processing have been removed. Hence, it is recommended to use this recent firmware for analysing attenuated backscatter profiles. To allow for consistent processing of historic data, correction procedures have been developed that account for artefacts detected in data collected with older firmware. Furthermore, a procedure is proposed to determine and account for the instrument-related background signal from electronic and optical components. This is necessary for using attenuated backscatter observations from any CL31 ceilometer. Recommendations are made for the processing of attenuated backscatter observed with Vaisala CL31 sensors, including the estimation of noise which is not provided in the standard CL31 output. After taking these aspects into account, attenuated backscatter profiles from Vaisala CL31 ceilometers are considered capable of providing valuable information for a range of applications including atmospheric boundary layer studies, detection of elevated aerosol layers, and model verification.

Ion chromatography for determination of nitrite and nitrate in seawater using monolithic ODS columns.

PubMed

Ito, Kazuaki; Takayama, Yohichi; Makabe, Nobuyuki; Mitsui, Ryo; Hirokawa, Takeshi

2005-08-12

A fast and highly sensitive ion chromatographic method using monolithic ODS columns was developed for the determination of nitrite (NO2-) and nitrate (NO3-) in seawater. Two monolithic ODS columns (50 mm x 4.6 mm i.d. + 100 mm x 4.6 mm i.d.) connected in series were coated and equilibrated with 5 mM cetyltrimethylammonium chloride (CTAC) aqueous solution. The column efficiency with 0.5 M NaCl as the mobile phase did not decrease in spite of the increase in flow rate of the mobile phase. Thus, good chromatograms were obtained within 3 minutes for NO2- and NO3 in artificial seawater without interferences by coexisting ions. The detection limit (S/N = 3) with UV detection at 225 nm was 0.8 and 1.6 microg/L for NO2- and NO3-, respectively. The characteristics of the monolithic CTA(+)-coated ODS columns were discussed. The present method was successfully applied to the fast and sensitive determination of NO2- and NO3- in real seawater samples.

Effect of pH on Cl sup minus transport in TAL of Henle's loop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondo, Yoshiaki; Yoshitomi, Koji; Imai, Masashi

1987-12-01

To further characterize the mechanism of Cl{sup {minus}} transport across the hamster thin ascending limb (TAL) of Henle's loop, the authors examined effects of pH on Cl{sup {minus}} permeability as determined by either the choline chloride diffusion voltage or the lumen-to-bath {sup 36}Cl flux in the isolated segments perfused in vitro. When pH of the bathing fluid or the perfusate was reduced from 7.4 to 5.8, the Cl{sup {minus}}-Na{sup +} permeability ratio was reduced from 2.77 {plus minus} 0.21 to 0.48 {plus minus} 0.02 or from 2.55 {plus minus} 0.15 to 0.81 {plus minus} 0.11, respectively. At 37{degree}C, when themore » pH of the bathing fluid was reduced from 7.4 to 6.2, the lumen-to-bath flux coefficient for {sup 36}Cl was reduced from 84.8 {plus minus} 7.5 to 20.4 {plus minus} 3.2, whereas the value for {sup 22}Na was unchanged. From the pH titration curves for P{sub Cl}/P{sub Na}, pK{sub a} values for proton binding were 6.31 and 5.78, and Hill's coefficients were 2.1 and 2.3 on the basolateral side and on the luminal side, respectively. Intracellular acidification with o-nitrophenylacetate also decreased the Cl{sup {minus}} permeability. They conclude that (1) Cl{sup {minus}} transport across the TAL is mediated by a process that is sensitive to ambient pH, (2) the basolateral side is more sensitive to pH, (3) the proton binding exhibits positive cooperativity in the modulation of Cl{sup {minus}} transport, and (4) intracellular pH might also modulate Cl{sup {minus}} transport.« less

Response of Cs 2LiYCl 6:Ce (CLYC) to High Energy Protons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coupland, Daniel David Schechtman; Stonehill, Laura Catherine; Goett III, John Jerome

2015-11-23

Cs 2LiYCl 6:Ce (CLYC) is a promising new inorganic scintillator for gamma and neutron detection. As a gamma-ray detector, it exhibits bright light output and better resolution and proportionality of response than traditional gamma-ray scintillators such as NaI. It is also highly sensitive to thermal neutrons through capture on 6Li, and recent experiments have demonstrated sensitivity to fast neutrons through interactions with 35Cl. The response of CLYC to other forms of radiation has not been reported. We have performed the first measurements of the response of CLYC to several-hundred MeV protons. We have collected digitized waveforms from proton events, andmore » compare to those produced by gammas and thermal neutrons. Finally, we discuss the potential for pulse shape discrimination between them.« less

Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

PubMed

Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun

2016-02-01

Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

Development of a PCR/LDR/flow-through hybridization assay using a capillary tube, probe DNA-immobilized magnetic beads and chemiluminescence detection.

PubMed

Hommatsu, Manami; Okahashi, Hisamitsu; Ohta, Keisuke; Tamai, Yusuke; Tsukagoshi, Kazuhiko; Hashimoto, Masahiko

2013-01-01

A polymerase chain reaction (PCR)/ligase detection reaction (LDR)/flow-through hybridization assay using chemiluminescence (CL) detection was developed for analyzing point mutations in gene fragments with high diagnostic value for colorectal cancers. A flow-through hybridization format using a capillary tube, in which probe DNA-immobilized magnetic beads were packed, provided accelerated hybridization kinetics of target DNA (i.e. LDR product) to the probe DNA. Simple fluid manipulations enabled both allele-specific hybridization and the removal of non-specifically bound DNA in the wash step. Furthermore, the use of CL detection greatly simplified the detection scheme, since CL does not require a light source for excitation of the fluorescent dye tags on the LDR products. Preliminary results demonstrated that this analytical system could detect both homozygous and heterozygous mutations, without the expensive instrumentation and cumbersome procedures required by conventional DNA microarray-based methods.

Synthesis of Nitrogen-Doped Graphene Quantum Dots at Low Temperature for Electrochemical Sensing Trinitrotoluene.

PubMed

Cai, Zhewei; Li, Fumin; Wu, Ping; Ji, Lijuan; Zhang, Hui; Cai, Chenxin; Gervasio, Dominic F

2015-12-01

Nitrogen-doped graphene quantum dots (N-GQDs) are synthesized at low temperature as a new catalyst allowing electrochemical detection of 2,4,6-trinitrotoluene (TNT). N-GQDs are made by an oxidative ultrasonication of graphene oxide (GO) forming nanometer-sized species, which are then chemically reduced and nitrogen doped by reacting with hydrazine. The as-synthesized N-GQDs have an average diameter of ∼2.5 nm with an N/C atomic ratio of up to ∼6.4%. To detect TNT, TNT is first accumulated on N-GQDs modified glassy carbon (N-GQDs/GC) electrode by holding the electrode at a 0 V versus Ag/AgCl for 150 s in an aqueous TNT solution. Next, the N-GQDs/GC electrode with accumulated TNT is transferred to a fresh PBS solution (0.1 M, pH 7.0, without TNT), where the TNT reduction current at -0.36 V versus Ag/AgCl in a linear scan voltammogram (LSV) shows a linear response to TNT concentration in the aqueous solution from 1 to 400 ppb, with a correlation coefficient of 0.999, a detection limit of 0.2 ppb at a signal/noise (S/N) of 3, and a detection sensitivity of 363 ± 7 mA mM(-1) cm(-2). The detection limit of 0.2 ppb of TNT for this new method is much lower than 2 ppb set by the U.S. Environmental Protection Agency for drinking water. Therefore, N-GQDs allow an electrochemical method for assaying TNT in drinking water to determine if levels of TNT are safe or not.

Validation of paper-based assay for rapid blood typing.

PubMed

Al-Tamimi, Mohammad; Shen, Wei; Zeineddine, Rania; Tran, Huy; Garnier, Gil

2012-02-07

We developed and validated a new paper-based assay for the detection of human blood type. Our method involves spotting a 3 μL blood sample on a paper surface where grouping antibodies have already been introduced. A thin film chromatograph tank was used to chromatographically elute the blood spot with 0.9% NaCl buffer for 10 min by capillary absorption. Agglutinated red blood cells (RBCs) were fixed on the paper substrate, resulting in a high optical density of the spot, with no visual trace in the buffer wicking path. Conversely, nonagglutinated RBCs could easily be eluted by the buffer and had low optical density of the spot and clearly visible trace of RBCs in the buffer wicking path. Different paper substrates had comparable ability to fix agglutinated blood, while a more porous substrate like Kleenex paper had enhanced ability to elute nonagglutinated blood. Using optimized conditions, a rapid assay for detection of blood groups was developed by spotting blood to antibodies absorbed to paper and eluted with 200 μL of 0.9% NaCl buffer directly by pipetting. RBCs fixation on paper accurately detected blood groups (ABO and RhD) using ascending buffer for 10 min or using a rapid elution step in 100/100 blood samples including 4 weak AB and 4 weak RhD samples. The assay has excellent reproducibility where the same blood group was obtained in 26 samples assessed in 2 different days. Agglutinated blood fixation on porous paper substrate provides a new, simple, and sensitive assay for rapid detection of blood group for point-of-care applications. © 2011 American Chemical Society

Monster Clusters in the Young Universe? Weak-lensing Masses of SPT-CL J0205-5829 and MOO1014+0038 with HST Observations

NASA Astrophysics Data System (ADS)

Feilx Kim, Seojin; Jee, Myungkook James

2018-01-01

Measuring High-z clusters’ masses is very important as the cluster abundance is extremely sensitive to the cosmological parameters. However, deriving their masses from the intracluster medium properties (i.e., Sunyaev-Zel’dovich or X-ray observations) is not the best method because of their departure from the hydrostatic equilibrium. Fortunately, the “See Change” Hubble Space Telescope program offers a rare opportunity to measure them using weak gravitational lensing. We study SPT-CL J0205-5829 (z=1.322) and MOO1014+0038 (z=1.24) discovered in the SPT-SZ and MaDCoW Surveys, respectively. Previous non-lensing based approaches suggest that both targets might be extremely massive clusters. After carefully addressing various possible systematics from the Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) images, we successfully detect clear weak lensing signals. We present their 2-dimensional mass maps and compare our weak-lensing masses with previous ICM-based results.

A specific chemodosimeter for fluoride ion based on a pyrene derivative with trimethylsilylethynyl groups.

PubMed

Lu, Hua; Wang, Qiuhong; Li, Zhifang; Lai, Guoqiao; Jiang, Jianxiong; Shen, Zhen

2011-06-21

Pyrene derivative 1 containing four trimethylsilylethynyl substituents was synthesized and investigated as a chromogenic and fluorescent chemodosimeter sensor for fluoride ions. 1 showed a high sensitivity and specific selectivity over a rapid response time toward fluoride anions compared to other anions, such as Cl(-), Br(-), ClO(4)(-), H(2)PO(4)(-) and HPO(4)(2-). TD-DFT calculations showed that the delocalization of the σ-electrons of the silicon destabilized the HOMO energy level of 1, thus red shifting both its absorption and emission spectrum. The addition of F(-) removed the trimethylsilyl substituents and resulted in a blue shift of both the absorption and fluorescent spectra of 1, which could be monitored by the color change with the naked-eye. Moreover, an easy to prepare test paper, which was obtained by immersing a filter paper into a THF solution of 1, could be utilized to detect and estimate the concentration of fluoride anions in water.

A rapid method for the measurement of sulfur hexafluoride (SF6), trifluoromethyl sulfur pentafluoride (SF5CF3), and Halon 1211 (CF2ClBr) in hydrologic tracer studies

USGS Publications Warehouse

Busenberg, Eurybiades; Plummer, Niel

2010-01-01

A rapid headspace method for the simultaneous laboratory determination of intentionally introduced hydrologic tracers, sulfur hexafluoride (SF6), trifluoromethyl sulfur pentafluoride (SF5CF3), Halon 1211 (CF2ClBr), and other halocarbons in water and gases is described. The high sensitivity of the procedure allows for introduction of minimal tracer mass (a few grams) into hydrologic systems with a large dynamic range of analytical detection (dilutions to 1:108). Analysis times by gas chromatography with electron capture detector are less than 1 min for SF6; about 2 min for SF6 and SF5CF3; and 4 min for SF6, SF5CF3, and Halon 1211. Many samples can be rapidly collected, preserved in stoppered septum bottles, and analyzed at a later time in the laboratory. Examples are provided showing the effectiveness of the gas tracer test studies in varied hydrogeological settings.

A rapid method for the measurement of sulfur hexafluoride (SF6), trifluoromethyl sulfur pentafluoride (SF5CF3), and Halon 1211 (CF2ClBr) in hydrologic tracer studies

NASA Astrophysics Data System (ADS)

Busenberg, Eurybiades; Plummer, L. Niel

2010-11-01

A rapid headspace method for the simultaneous laboratory determination of intentionally introduced hydrologic tracers, sulfur hexafluoride (SF6), trifluoromethyl sulfur pentafluoride (SF5CF3), Halon 1211 (CF2ClBr), and other halocarbons in water and gases is described. The high sensitivity of the procedure allows for introduction of minimal tracer mass (a few grams) into hydrologic systems with a large dynamic range of analytical detection (dilutions to 1:108). Analysis times by gas chromatography with electron capture detector are less than 1 min for SF6; about 2 min for SF6 and SF5CF3; and 4 min for SF6, SF5CF3, and Halon 1211. Many samples can be rapidly collected, preserved in stoppered septum bottles, and analyzed at a later time in the laboratory. Examples are provided showing the effectiveness of the gas tracer test studies in varied hydrogeological settings.

Potassium permanganate-glutaraldehyde chemiluminescence system catalyzed by gold nanoprisms toward selective determination of fluoride.

PubMed

Abolhasani, Jafar; Hassanzadeh, Javad; Ghorbani-Kalhor, Ebrahim

2016-02-01

Gold and silver nanoparticles (NPs) are shown to exert a positive effect on the chemiluminescence (CL) reaction of permanganate aldehydes. Interestingly, between various shapes examined, Au nanoprisms have the highest beneficial effect. This effect is even more notable in the presence of sodium dodecyl sulfate (SDS) surfactant. UV-vis spectra and transmission electron microscopy were used to characterize the NP shapes and sizes. Furthermore, it was observed that iron(III) ions can slightly increase CL emission of this system. This intensification is very effective in the presence of fluoride ions (F(-)). These observations form the basis of the method for the high sensitive determination of F(-) in the 6-1200 nmol L(-1) concentration range, with a detection limit of 2.1 nmol L(-1). The proposed method has good precision and was satisfactorily used in the selective determination of low concentrations of fluoride ion in real samples. Copyright © 2015 John Wiley & Sons, Ltd.

Synchronized flash photolysis and pulse deposition in matrix isolation experiments

NASA Technical Reports Server (NTRS)

Allamandola, Louis J.; Lucas, Donald; Pimentel, George C.

1978-01-01

An apparatus is described which permits flash photolysis of a pulse-deposited gas mixture in a matrix isolation experiment. This technique obviates the limitations of in situ photolysis imposed by the cage effect and by secondary photolysis. The matrix is deposited in pulses at 30-s intervals and photolyzed sequentially by four synchronized flashlamps approximately 1 ms before the pulse strikes the cold surface. Pulsed deposition maintains adequate isolation and causes line narrowing, which enhances spectral sensitivity. The efficacy of flash photolysis combined with pulsed deposition for producing and trapping transient species was demonstrated by infrated detection of CF3 (from photolysis of CF3I/Ar mixtures) and of ClCO (from photolysis of Cl2/CO/Ar mixtures). The apparatus was used to study the photolytic decomposition of gaseous tricarbonylironcyclobutadiene, C4H4Fe(CO)3. The results indicate that the primary photolytic step is not elimination of C4H4, as suggested earlier, but rather of CO.

Ongoing ingestive behavior is rapidly suppressed by a preabsorptive, intestinal “bitter taste” cue

PubMed Central

Davidson, Terry L.; Powley, Terry L.

2011-01-01

The discovery that cells in the gastrointestinal (GI) tract express the same molecular receptors and intracellular signaling components known to be involved in taste has generated great interest in potential functions of such post-oral “taste” receptors in the control of food intake. To determine whether taste cues in the GI tract are detected and can directly influence behavior, the present study used a microbehavioral analysis of intake, in which rats drank from lickometers that were programmed to simultaneously deliver a brief yoked infusion of a taste stimulus to the intestines. Specifically, in daily 30-min sessions, thirsty rats with indwelling intraduodenal catheters were trained to drink hypotonic (0.12 M) sodium chloride (NaCl) and simultaneously self-infuse a 0.12 M NaCl solution. Once trained, in a subsequent series of intestinal taste probe trials, rats reduced licking during a 6-min infusion period, when a bitter stimulus denatonium benzoate (DB; 10 mM) was added to the NaCl vehicle for infusion, apparently conditioning a mild taste aversion. Presentation of the DB in isomolar lithium chloride (LiCl) for intestinal infusions accelerated the development of the response across trials and strengthened the temporal resolution of the early licking suppression in response to the arrival of the DB in the intestine. In an experiment to evaluate whether CCK is involved as a paracrine signal in transducing the intestinal taste of DB, the CCK-1R antagonist devazepide partially blocked the response to intestinal DB. In contrast to their ability to detect and avoid the bitter taste in the intestine, rats did not modify their licking to saccharin intraduodenal probe infusions. The intestinal taste aversion paradigm developed here provides a sensitive and effective protocol for evaluating which tastants—and concentrations of tastants—in the lumen of the gut can control ingestion. PMID:21865540

A genetically-encoded YFP sensor with enhanced chloride sensitivity, photostability and reduced ph interference demonstrates augmented transmembrane chloride movement by gerbil prestin (SLC26a5).

PubMed

Zhong, Sheng; Navaratnam, Dhasakumar; Santos-Sacchi, Joseph

2014-01-01

Chloride is the major anion in cells, with many diseases arising from disordered Cl- regulation. For the non-invasive investigation of Cl- flux, YFP-H148Q and its derivatives chameleon and Cl-Sensor previously were introduced as genetically encoded chloride indicators. Neither the Cl- sensitivity nor the pH-susceptibility of these modifications to YFP is optimal for precise measurements of Cl- under physiological conditions. Furthermore, the relatively poor photostability of YFP derivatives hinders their application for dynamic and quantitative Cl- measurements. Dynamic and accurate measurement of physiological concentrations of chloride would significantly affect our ability to study effects of chloride on cellular events. In this study, we developed a series of YFP derivatives to remove pH interference, increase photostability and enhance chloride sensitivity. The final product, EYFP-F46L/Q69K/H148Q/I152L/V163S/S175G/S205V/A206K (monomeric Cl-YFP), has a chloride Kd of 14 mM and pKa of 5.9. The bleach time constant of 175 seconds is over 15-fold greater than wild-type EYFP. We have used the sensor fused to the transmembrane protein prestin (gerbil prestin, SLC26a5), and shown for the first time physiological (mM) chloride flux in HEK cells expressing this protein. This modified fluorescent protein will facilitate investigations of dynamics of chloride ions and their mediation of cell function. Modifications to YFP (EYFP-F46L/Q69K/H148Q/I152L/V163S/S175G/S205V/A206K (monomeric Cl-YFP) results in a photostable fluorescent protein that allows measurement of physiological changes in chloride concentration while remaining minimally affected by changes in pH.

HCV core-antigen assay as an alternative to HCV RNA quantification: A correlation study for the assessment of HCV viremia.

PubMed

Alonso, Roberto; Pérez-García, Felipe; López-Roa, Paula; Alcalá, Luis; Rodeño, Pilar; Bouza, Emilio

2018-03-01

Detection of hepatitis C virus (HCV) RNA and the HCV core antigen assay (HCV-Ag) are reliable techniques for the diagnosis of active and chronic HCV infection. Our aim was to evaluate the HCV-Ag assay as an alternative to quantification of HVC RNA. A comparison was made of the sensitivity and specificity of an HCV-Ag assay (204 serum samples) with those of a PCR assay, and the correlation between the two techniques was determined. The sensitivity and specificity of HCV-Ag was 76.6% and 100%, respectively. Both assays were extremely well correlated (Pearson coefficient=0.951). The formula (LogCV=1.15*LogAg+2.26) was obtained to calculate the viral load by PCR from HCV-Ag values. HCV-Ag was unable to detect viral loads below 5000IU/mL. Although the HCV-Ag assay was less sensitive than the PCR assay, the correlation between both assays was excellent. HCV-Ag can be useful as a first step in the diagnosis of acute or chronic HCV infection and in emergency situations. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Molecular and morphological characterization of Acanthamoeba isolated from corneal scrapes and contact lens wearers in Argentina.

PubMed

Casero, Rodolfo D; Mongi, Florencia; Laconte, Laura; Rivero, Fernando; Sastre, Dario; Teherán, Aníbal; Herrera, Giovanny; Ramírez, Juan David

2017-10-01

In this study, we describe the frequency of Acanthamoeba keratitis (AK) in patients that assisted in the Ophthalmology Department and determine the species/genotypes of free living amoebas (FLA) isolates. FLA from Corneal scrapes (CS) and contact lens (CL) wearers were studied by morphological and molecular characterization. A database was constructed with sociodemographic, clinical findings and history of use of CL variables. During January 2000 and September 2016 patients with corneal pathology admitted to the Ophthalmology Service of the University Hospital in Córdoba city, Argentina were included in the study. FLA were detected in 1.5% (11/739) and in 17% (11/65) of CS and CL analyzed respectively. FLA isolates from CL users evidenced an 80.9% of inappropriate lens maintenance, 4.8% (1/21) were not CL users that have been in contact with waters in outdoor environment and 14,3% (3/21) with no data about CL users. Acanthamoeba was confirmed in 100% and 82% of CS and LC respectively. The most frequent symptom associated with AK was red eye and photophobia. FLA from CS belonged to group II but 82% (9/11) and 18% (2/11) from CL belonged to group II and III respectively. T4 genotype and A. polyphaga species were detected in 100% of Acanthamoeba isolates. Poor CL hygiene practices, highlights the need for improved education about the severity of AK and consequences of improper CL hygiene. Genotype T4 detected in 100% of both CS and CL samples, consistently with previous findings indicating that this genotype is by far the most prevalent isolated from ocular infection. Copyright © 2017 Elsevier B.V. All rights reserved.

Thermoplastic Explosive Compositions on the Base of Hexanitrohexaazaisowurtzitane

NASA Astrophysics Data System (ADS)

Ilyin, V. P.; Smirnov, S. P.; Kolganov, E. V.; Pechenev, Yu. G.

2006-08-01

Hexanitrohexaazaisowurtzitane is an azostructural compound known as CL-20. We performed a series of experiments with CL-20 synthesized in Russia to evaluate the possibility to use it in pressed high explosive compositions. We used it in thermoplastic compositions both with an inert binder and energetic binder. The compositions were conventionally named CL-20И and CL-20A. It was determined that the thermoplastic compositions had the most high detonation parameters and a level of sensitivity to mechanical effects acceptable to allow their processing. Their detonation characteristics were compared with that of some known foreign compositions based on CL-20.

A re-evaluation of laser heterodyne radiometer ClO measurements. [for stratospheric chemistry studies

NASA Technical Reports Server (NTRS)

Menzies, R. T.

1983-01-01

Previously reported measurements of stratospheric ClO using a balloon-borne laser heterodyne radiometer, launched from Palestine, Texas, are re-evaluated as a result of recent spectroscopic data. A spectral feature which was observed during September, 1978 and November, 1979 flights was incorrectly identified as a ClO absorption line, while a second feature observed during the latter flight with somewhat limited sensitivity is now believed to be due to ClO. This new interpretation results in a measured ClO profile which falls off more rapidly with decreasing altitude than the previous results indicated.

Development of a Molecularly Imprinted Polymer-Based Sensor for the Electrochemical Determination of Triacetone Triperoxide (TATP)

PubMed Central

Mamo, Samuel Kassahun; Gonzalez-Rodriguez, Jose

2014-01-01

The explosive triacetone triperoxide (TATP), which can be prepared from commercially readily available reagents following an easy synthetic procedure, is one of the most common components of improvised explosive devices (IEDs). Molecularly-imprinted polymer (MIP) electrochemical sensors have proved useful for the determination of different compounds in different matrices with the required sensitivity and selectivity. In this work, a highly sensitive and selective molecularly imprinted polymer with electrochemical capabilities for the determination of TATP has been developed. The molecular imprinting has been performed via electropolymerisation onto a glassy carbon electrode surface by cyclic voltammetry from a solution of pyrrole functional monomer, TATP template and LiClO4. Differential Pulse Voltammetry of TATP, with LiClO4 as supporting electrolyte, was performed in a potential range of −2.0 V to +1.0 V (vs. Ag/AgCl). Three-factor two-level factorial design was used to optimise the monomer concentration at 0.1 mol·L−1, template concentration at 100 mmol·L−1 and the number of cyclic voltammetry scan cycles to 10. The molecularly imprinted polymer-modified glassy carbon electrode demonstrated good performance at low concentrations for a linear range of 82–44,300 μg·L−1 and a correlation coefficient of r2 = 0.996. The limits of detection (LoD) and quantification (LoQ) achieved were 26.9 μg·L−1 and 81.6 μg·L−1, respectively. The sensor demonstrated very good repeatability with precision values (n = 6, expressed as %RSD) of 1.098% and 0.55% for 1108 and 2216 μg·L−1, respectively. It also proved selective for TATP in the presence of other explosive substances such as PETN, RDX, HMX, and TNT. PMID:25490589

Detection of orbicularis oris muscle defects in first degree relatives of cleft lip children using ultrasound.

PubMed

Mittal, M; Maheshwari, N; Ahlawat, K; Sharma, V; Sultan, A; Chopra, R

2012-01-01

The severity of cleft lip (CL) varies considerably from complete bilateral CL and palate at one end of the spectrum to a minimal CL at the other. In some cases of microform clefting, there may be no visible manifestation of the defect on the lip surface (i.e., the defect is occult) and no residual functional deficit. This study used high resolution ultrasonography to detect subclinical anomalies of orbicularis oris muscle (OOM) in first degree relatives of CL +- cleft palate children and compared it with controls. Thirty relatives of 25 children with non-syndromic CL or CL+ CP were identified for the study. Thirty subjects having negative family history of CL/P in three generations and absence of any minimal cleft features were taken as controls. Ultrasound scans of OOM of all the controls and relatives were taken. Statistical analysis was performed using standard χ2 tests with Yates correction. Defects were seen in 13.3% of relatives and no defects were seen in controls, this was not statistically significant. The data support the hypothesis that subclinical CL cases with subepithelial OOM defects do exist and Orbicularis oris discontinuities represent the mildest form of CL.

Hydrazine-induced post-chemiluminescence phenomenon of permanganate-luminol reaction and its applications.

PubMed

Du, Jianxiu; Lu, Jiuru

2004-01-01

The post-chemiluminescence phenomenon arising from the permanganate-luminol reaction induced by hydrazine and isoniazid was investigated. When hydrazine or isoniazid was injected into the mixture after the end of the reaction of permanganate with alkaline luminol, a new chemiluminescence (CL) reaction was initiated and strong CL signal was detected. A possible CL mechanism is suggested, based upon the studies of the kinetic characteristics of the CL reaction, the UV-visible spectra, the CL spectra and some other experiments. The present reactions allow the determination of 0.1-10.0 mg/L hydrazine and 0.02-1.0 mg/L isoniazid, with detection limits of 0.03 mg/L and 0.006 mg/L, respectively. The method was applied to the determination of isoniazid in pharmaceutical preparations.

Aqueous corrosion and corrosion-sensitive embrittlement of Fe{sub 3}Al-based and lean-aluminum iron aluminides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, J.G.; Buchanan, R.A.

Aqueous corrosion and corrosion-sensitive embrittlement of iron aluminides were characterized as functions of environment, alloying content, notch sensitivity, and strain rate. Polarization resistance and cyclic anodic polarization evaluations were performed in 3.5 wt % NaCl, 200 ppM Cl{sup {minus}} (pH = 4), and 1 N NaOH solutions. In the mild acid-chloride solution [200 ppM Cl{sup {minus}} (pH = 4)], the pitting-corrosion resistance of the new lean-aluminum iron aluminides (FAP-Y and CM-Mo) was comparable to that of the Fe{sub 3}Al-based FAL-Mo. In the higher-chloride 3.5 wt % NaCl, the resistance of CM-Mo was slightly less but FAP-Y showed quite similar behaviormore » to FAL-Mo. In 1 N NaOH solution, all materials exhibited ideal passive behavior. Under slow-strain-rate test conditions in the mild acid-chloride electrolyte, prior work had shown the ductilities (% elongations) of Fe{sub 3}Al-based materials to be {approximately}7% and {approximately}1% at the freely-corroding and hydrogen-charging potentials, respectively. Present studied on the lean-aluminum materials have shown the ductilities to be {approximately}17% and {approximately}5%, respectively. Thus, the present results indicate that these new materials have reasonably-good aqueous-corrosion properties in chloride environments and significantly-enhanced ductilities under aqueous corrosion conditions. The strain rate and notch sensitivities of high-aluminum iron aluminide (FA-129) were investigated by performing slow-strain-rate tests. The notch sensitivity was independent of strain rate and the notch sensitivity in the aqueous environment was similar to that in air.« less

Bumetanide-sensitive ion fluxes in vascular smooth muscle cells: lack of functional Na+, K+, 2 Cl- cotransport.

PubMed

Orlov, S N; Tremblay, J; Hamet, P

1996-09-01

To examine the involvement of Na+,K+,2Cl- cotransport in monovalent ion fluxes in vascular smooth muscle cells (VSMC), we compared the effect of bumetanide on 86Rb, 36Cl and 22Na uptake by quiescent cultures of VSMC from rat aorta. Under basal conditions, the values of bumetanide-sensitive (BS) inward and outward 86Rb fluxes were not different. Bumetanide decreased basal 86Rb uptake by 70-75% with a Ki of approximately 0.2-0.3 microM. At concentrations ranging up to 1 microM, bumetanide did not affect 36Cl influx and reduced it by 20-30% in the range from 3 to 100 microM. In contrast to 86Rb and 36Cl influx, bumetanide did not inhibit 22Na uptake by VSMC. BS 86Rb uptake was completely abolished in Na(+)- or Cl(-)-free media. In contrast to 86Rb, basal BS 36Cl influx was not affected by Nao+ and Ko+. Hyperosmotic and isosmotic shrinkage of VSMC increased 86Rb and 36Cl influx to the same extent. Shrinkage-induced increments of 86Rb and 36Cl uptake were completely abolished by bumetanide with a Ki or approximately 0.3 microM. Shrinkage did not induce BS 86Rb and 36Cl influx in (Na+ or Cl-)- and (Na+ or K+)-depleted media, respectively. In the presence of an inhibitor of Na+/H+ exchange (EIPA), neither hyperosmotic nor isosmotic shrinkage activated 22Na influx. Bumetanide (1 microM) did not modify basal VSMC volume and intracellular content of sodium, potassium and chloride but abolished the regulatory volume increase in isosmotically-shrunken VSMC. These data demonstrate the absence of the functional Na+,K+,2Cl- cotransporter in VSMC and suggest that in these cells basal and shrinkage-induced BS K+ influx is mediated by (Nao+ + Clo-)-dependent K+/K+ exchange and Nao(+)-dependent K+,Cl- cotransport, respectively.

Mononuclear cells, mast cells and mucous cells as part of the delayed hypersensitivity response to aerosolized antigen in mice.

PubMed Central

Enander, I; Ahlstedt, S; Nygren, H

1984-01-01

Mice (BALB/c) exposed to picryl chloride (PiCl) on their shaved abdomen and untreated animals were after 7 days exposed to daily aerosolized trinitrophenylated dog serum albumin (TNP-DSA). Mice exposed to PiCl tended to respond earlier and more strongly with both delayed hypersensitivity (DH) and IgG antibodies in serum and bronchial washings than did mice exposed to aerosol only. Picryl chloride sensitization resulted in spontaneously proliferating axillary lymph node cells, which could not be further stimulated with antigen or mitogen. Histological examination of lung tissue of aerosol-sensitized animals revealed an increase in mononuclear cells and mast cells around bronchioli and mucous cells, particularly in those animals exposed for prolonged periods and sensitized with PiCl prior to aerosol. Sensitization of mice with aerosolized TNP-DSA administrated in two 2- and 1-week periods with a 4-week interval responded with DH and IgG antibody in a dose dependent fashion irrespective of presensitization with PiCl. In bronchial washings IgG antibodies were found particularly after two 2-week periods of exposure. The cells taken from the axillary or brachial lymph nodes showed spontaneous proliferation. Culture of the cells to achieve mast cell maturation resulted in no or very low numbers of mast cells in the lymph nodes. PMID:6706375

EUVS Sounding Rocket Payload

NASA Technical Reports Server (NTRS)

Stern, Alan S.

1996-01-01

During the first half of this year (CY 1996), the EUVS project began preparations of the EUVS payload for the upcoming NASA sounding rocket flight 36.148CL, slated for launch on July 26, 1996 to observe and record a high-resolution (approx. 2 A FWHM) EUV spectrum of the planet Venus. These preparations were designed to improve the spectral resolution and sensitivity performance of the EUVS payload as well as prepare the payload for this upcoming mission. The following is a list of the EUVS project activities that have taken place since the beginning of this CY: (1) Applied a fresh, new SiC optical coating to our existing 2400 groove/mm grating to boost its reflectivity; (2) modified the Ranicon science detector to boost its detective quantum efficiency with the addition of a repeller grid; (3) constructed a new entrance slit plane to achieve 2 A FWHM spectral resolution; (4) prepared and held the Payload Initiation Conference (PIC) with the assigned NASA support team from Wallops Island for the upcoming 36.148CL flight (PIC held on March 8, 1996; see Attachment A); (5) began wavelength calibration activities of EUVS in the laboratory; (6) made arrangements for travel to WSMR to begin integration activities in preparation for the July 1996 launch; (7) paper detailing our previous EUVS Venus mission (NASA flight 36.117CL) published in Icarus (see Attachment B); and (8) continued data analysis of the previous EUVS mission 36.137CL (Spica occultation flight).

Effect of passive sensitization on the mechanical activity of human isolated bronchial smooth muscle induced by substance P, neurokinin A and VIP.

PubMed

Ben-Jebria, A; Marthan, R; Rossetti, M; Savineau, J P

1993-05-01

1. The effect of passive sensitization on the mechanical activity of human isolated bronchial smooth muscle induced by the following neuropeptides substance P (SP), neurokinin A (NKA) and vasoactive intestinal peptide (VIP) was studied both in the absence and in the presence of the neutral endopeptidase (NEP) inhibitor, phosphoramidon. 2. Cumulative concentration-response curves (CCRC) to these neuropeptides were constructed in human passively sensitized isolated bronchial rings and compared to those in paired controls. Passively sensitized human isolated bronchial rings were tissues incubated overnight in serum from asthmatic patients atopic to Dermatophagoides pteronyssinus and paired controls were tissues originating from the same lung specimens but incubated overnight in serum from healthy donors. 3. In the absence of phosphoramidon, passive sensitization significantly increased the amplitude of the contractile responses to SP and NKA including that to the maximal concentration given from 50 +/- 5% to 76 +/- 6% (n = 5, P < 0.05) and from 70 +/- 7% to 101 +/- 6% (n = 5, P < 0.05) of the maximal response to acetylcholine, respectively. Passive sensitization significantly shifted to the left the CCRC for both tachykinins as measured by the geometric means dose-ratios which were 8.5 (95% confidence limits (CL): 3.1-13.9) and 7.3 (95% CL: 4.2-10.3) for SP and NKA, respectively. 4. In the presence of phosphoramidon (10 microM), passive sensitization still increased significantly the amplitude of the contractile responses to SP and NKA including that to the maximal concentration given from 74 +/- 4% to 115 +/- 7% (n = 5, P<0.05) and from 104 +/- 9% to 146 +/- 16% (n = 5, P<0.05)of the maximal response to acetylcholine, respectively. Passive sensitization still significantly shifted to the left the CCRC for both tachykinins as measured by the dose-ratios which were 9.0 (95% CL:4.3-13.6) and 5.4 (95% CL: 2.9-7.9) for SP and NKA, respectively.5. The relaxant response to the maximal concentration of VIP given in tissues precontracted with histamine (0.5 mM) was significantly reduced by passive sensitization from 41 +/- 4% to 25 +/- 3% (n = 5,P <0.05) of the amplitude of the precontraction in the absence of phosphoramidon and from 72 +/- 1%to 49 +/- 4% (n = 5, P<0.05) in the presence of phosphoramidon (10 microM). Passive sensitization significantly shifted to the right the CCRC for VIP as measured by the dose-ratios which were 10.4(95% CL: 6.6-14.1) and 6.4 (95% CL: 3.0-9.8) in the absence and in the presence of phosphoramidon,respectively.6. We conclude that passive sensitization enhances the mechanical response to neuropeptides which contract human isolated bronchial smooth muscle and reduces that to a neuropeptide which relaxes it.The mechanism of passive sensitization-induced changes in the mechanical activity appears to be independent of a decrease in NEP activity since these changes persist in the presence of the NEP inhibitor, phosphoramidon.

Changes in taste receptor cell [Ca2+]i modulate chorda tympani responses to salty and sour taste stimuli

PubMed Central

DeSimone, John A.; Ren, ZuoJun; Phan, Tam-Hao T.; Heck, Gerard L.; Mummalaneni, Shobha

2012-01-01

The relationship between taste receptor cell (TRC) Ca2+ concentration ([Ca2+]i) and rat chorda tympani (CT) nerve responses to salty [NaCl and NaCl+benzamil (Bz)] and sour (HCl, CO2, and acetic acid) taste stimuli was investigated before and after lingual application of ionomycin+Ca2+, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester (BAPTA-AM), U73122 (phospholipase C blocker), and thapsigargin (Ca2+-ATPase inhibitor) under open-circuit or lingual voltage-clamp conditions. An increase in TRC [Ca2+]i attenuated the tonic Bz-sensitive NaCl CT response and the apical membrane Na+ conductance. A decrease in TRC [Ca2+]i enhanced the tonic Bz-sensitive and Bz-insensitive NaCl CT responses and apical membrane Na+ conductance but did not affect CT responses to KCl or NH4Cl. An increase in TRC [Ca2+]i did not alter the phasic response but attenuated the tonic CT response to acidic stimuli. A decrease in [Ca2+]i did not alter the phasic response but attenuated the tonic CT response to acidic stimuli. In a subset of TRCs, a positive relationship between [H+]i and [Ca2+]i was obtained using in vitro imaging techniques. U73122 inhibited the tonic CT responses to NaCl, and thapsigargin inhibited the tonic CT responses to salty and sour stimuli. The results suggest that salty and sour taste qualities are transduced by [Ca2+]i-dependent and [Ca2+]i-independent mechanisms. Changes in TRC [Ca2+]i in a BAPTA-sensitive cytosolic compartment regulate ion channels and cotransporters involved in the salty and sour taste transduction mechanisms and in neural adaptation. Changes in TRC [Ca2+]i in a separate subcompartment, sensitive to inositol trisphosphate and thapsigargin but inaccessible to BAPTA, are associated with neurotransmitter release. PMID:22956787

Metagenomics of Microbial Communities in Gallbladder Bile from Patients with Gallbladder Cancer or Cholelithiasis

PubMed

Tsuchiya, Yasuo; Loza, Ernest; Villa-Gomez, Guido; Trujillo, Carlos C; Baez, Sergio; Asai, Takao; Ikoma, Toshikazu; Endoh, Kazuo; Nakamura, Kazutoshi

2018-04-25

Salmonella typhi and Helicobacter infections have been shown to increase risk of gallbladder cancer (GBC), but findings have been inconsistent. Other bacterial infections may also be associated with GBC. However, information on microbial pathogens in gallbladder bile of GBC patients is scarce. We aimed to investigate the microbial communities in gallbladder bile of patients with GBC and cholelithiasis (CL). Seven GBC patients and 30 CL patients were enrolled in this study. Genomic DNA was extracted from bile and the V3-V4 region of 16S rRNA was amplified. The sequencing results were compared with the 16S database, and the bacteria were identified by homology searches and phylogenetic analysis. DNA was detected in the bile of three GBC (42.9%; Bolivia, 1; Chile, 2) and four CL patients (13.3%; Bolivia, 1; Chile, 3). Of the 37 patients, 30 (81.1%) were negative and unable to analyze. Salmonella typhi and Helicobacter sp. were not detected in bile from any GBC patients. As the predominant species, Fusobacterium nucleatum, Escherichia coli, and Enetrobacter sp. were detected in bile from GBC patients. Those in bile from CL patients were Escherichia coli, Salmonella sp., and Enerococcus gallinarum. Escherichia coli was detected in bile samples from both GBC and CL patients. Whether the bacteria detected in bile from GBC patients would associated with the development of GBC warrant further investigation. Creative Commons Attribution License

Carbon nanopipette electrodes for dopamine detection in Drosophila

PubMed Central

Rees, Hillary R.; Anderson, Sean E.; Privman, Eve; Bau, Haim H.; Venton, B. Jill

2015-01-01

Small, robust, sensitive electrodes are desired for in vivo neurotransmitter measurements. Carbon nanopipettes have been previously manufactured and used for single cell drug delivery and electrophysiological measurements. Here, a modified fabrication procedure was developed to produce batches of solid carbon nanopipette electrodes (CNPEs) with ~250 nm diameter tips, and controllable lengths of exposed carbon, ranging from 5 μm to 175 μm. The electrochemical properties of CNPEs were characterized with fast-scan cyclic voltammetry (FSCV) for the first time. CNPEs were used to detect the electroactive neurotransmitters dopamine, serotonin, and octopamine. CNPEs were significantly more sensitive for serotonin detection than traditional carbon fiber microelectrodes (CFMEs). Similar to CFMEs, CNPEs have a linear response for dopamine concentrations ranging from 0.1 to 10 μM and a LOD of 25 ± 5 nM. Recordings with CNPEs were stable for over 3 hours when the applied triangle waveform was scanned between −0.4 and 1.3 V vs. Ag/AgCl/Cl− at 400 V/s. CNPEs were used to detect endogenous dopamine release in Drosophila larvae using optogenetics, which verified the utility of CNPEs for in vivo neuroscience studies. CNPEs are advantageous because they are an order of magnitude smaller in diameter than typical CFMEs and have a sharp, tunable geometry that facilitates penetration and implantation for localized measurements in distinct regions of small organisms, such as the Drosophila brain. PMID:25711512

Gold nanocages decorated biocompatible amine functionalized graphene as an efficient dopamine sensor platform.

PubMed

Daemi, Sahar; Ashkarran, Ali Akbar; Bahari, Ali; Ghasemi, Shahram

2017-05-15

Nanocomposite of gold nanocages and chemically modified graphene oxide (GNCs/CMG) was synthesized in N,N-dimethylformamide (DMF) for sensitive detection of dopamine (DA). DA is widely spread in central nervous system which can regulates essential body functions like movement and emotional behaviour. In this regard sensitive and fast detection of DA level in human body is still challenging considering its interference with other biomolecules in biological samples. CMG was synthesized through amine modification of graphene oxide (GO) with DMF at relatively high temperature followed by attachment of GNCs, fabricated using a galvanic replacement between silver nanocubes and HAuCl 4 solution in the DMF. X-ray diffraction (XRD) pattern of GNCs/CMG nanocomposite revealed high crystallization of GNCs attached to the graphene nanosheets and microscopic images revealed relatively uniform decoration of GNCs on the surface of CMG. Nanocomposite modified glassy carbon electrode (GNCs/CMG/GCE) was used to investigate the electrochemical behaviour of DA with cyclic voltammetry and amperometry techniques. The linear range for dopamine was between 0.1 and 80μM with a low detection limit of 0.02μM. Furthermore, GNCs/CMG/GCE exhibited satisfying reproducibility, long-term stability and high selectivity for DA detection in large amount of ascorbic acid with good results for determination in human serum samples. Copyright © 2017 Elsevier Inc. All rights reserved.

Iron oxide/carbon black (Fe2O3/CB) composite electrode for the detection of reduced nicotinamide cofactors using an amperometric method under a low overpotential.

PubMed

Kim, Yang Hee; Kim, Taeho; Ryu, Ji Heon; Yoo, Young Je

2010-01-15

An amperometric biosensor for the detection of the reduced nicotinamide cofactors NADH and NADPH was designed, based on the electrochemical oxidation of NAD(P)H with an iron oxide/carbon black composite (Fe(2)O(3)/CB) electrode. The electrode exhibited excellent performances in that it led to a substantial decrease in the overpotential of electrochemical NADH oxidation. Iron oxide plays a significant role as a catalyst for NADH oxidation and the reaction occurs at +0.00 V (vs. Ag/AgCl). The method of the sensor construction is very simple and the sensor performed well, giving high sensitivity, high stability, and a broad detection range. The sensitivity of this system is 2.54 microA mM(-1) and the limit of detection (S/N=3) is 10 microM. A linear range was observed between 10 microM and 1000 microM of NADH (R(2)=0.993), which is preferable to that of the previous studies. The Fe(2)O(3)/CB electrode also oxidizes NADPH under the same condition and can be applied as an NADPH sensor. Moreover, when the sensor system was integrated into a dehydrogenase-based sensor system, it also showed a good sensing performance. Copyright 2009 Elsevier B.V. All rights reserved.

Enriched Boron-Doped Amorphous Selenium Based Position-Sensitive Solid-State Thermal Neutron Detector for MPACT Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mandal, Krishna

High-efficiency thermal neutron detectors with compact size, low power-rating and high spatial, temporal and energy resolution are essential to execute non-proliferation and safeguard protocols. The demands of such detector are not fully covered by the current detection system such as gas proportional counters or scintillator-photomultiplier tube combinations, which are limited by their detection efficiency, stability of response, speed of operation, and physical size. Furthermore, world-wide shortage of 3He gas, required for widely used gas detection method, has further prompted to design an alternative system. Therefore, a solid-state neutron detection system without the requirement of 3He will be very desirable. Tomore » address the above technology gap, we had proposed to develop new room temperature solidstate thermal neutron detectors based on enriched boron ( 10B) and enriched lithium ( 6Li) doped amorphous Se (As- 0.52%, Cl 5 ppm) semiconductor for MPACT applications. The proposed alloy materials have been identified for its many favorable characteristics - a wide bandgap (~2.2 eV at 300 K) for room temperature operation, high glass transition temperature (t g ~ 85°C), a high thermal neutron cross-section (for boron ~ 3840 barns, for lithium ~ 940 barns, 1 barn = 10 -24 cm 2), low effective atomic number of Se for small gamma ray sensitivity, and high radiation tolerance due to its amorphous structure.« less

Zepto-molar electrochemical detection of Brucella genome based on gold nanoribbons covered by gold nanoblooms

NASA Astrophysics Data System (ADS)

Rahi, Amid; Sattarahmady, Naghmeh; Heli, Hossein

2015-12-01

Gold nanoribbons covered by gold nanoblooms were sonoelectrodeposited on a polycrystalline gold surface at -1800 mV (vs. AgCl) with the assistance of ultrasound and co-occurrence of the hydrogen evolution reaction. The nanostructure, as a transducer, was utilized to immobilize a Brucella-specific probe and fabrication of a genosensor, and the process of immobilization and hybridization was detected by electrochemical methods, using methylene blue as a redox marker. The proposed method for detection of the complementary sequence, sequences with base-mismatched (one-, two- and three-base mismatches), and the sequence of non-complementary sequence was assayed. The fabricated genosensor was evaluated for the assay of the bacteria in the cultured and human samples without polymerase chain reactions (PCR). The genosensor could detect the complementary sequence with a calibration sensitivity of 0.40 μA dm3 mol-1, a linear concentration range of 10 zmol dm-3 to 10 pmol dm-3, and a detection limit of 1.71 zmol dm-3.

A novel pyridyl triphenylamine-BODIPY aldoxime: Naked-eye visible and fluorometric chemodosimeter for hypochlorite.

PubMed

Xu, Xiu-Xiu; Qian, Ying

2017-08-05

An aldoxime containing fluorescent probe based on vinylpydine-appended triphenylamine-BODIPY has been designed and used for hypochlorite detection. OX-PPA-BODIPY was developed by introducing an aldoxime group into the 2-position of BODIPY, which can be used for the detection of hypochlorite with a sharp color change from pink to green. The attachment of 4-vinylpyridine moiety to triphenylamine-BODIPY constructs a fluorogen with desirable conjugated system. The probe, which displays extremely weak fluorescence owing to the CN isomerization mechanism at 2-position of BODIPY, responds to HClO/ClO - through a dramatic enhancement of its fluorescence intensity. This new probe, a naked-eye visible and fluorometric chemodosimeter, exhibits high selectivity and sensitivity toward hypochlorite over other reactive oxygen species (ROS) and anions. The detection is accompanied by a 20-fold increase in fluorescent intensity (Φ F from 0.02 to 0.43). The detection limit of the probe for hypochlorite is 7.37×10 -7 M. Moreover, OX-PPA-BODIPY can be used to detect hypochlorite in real water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

A novel pyridyl triphenylamine-BODIPY aldoxime: Naked-eye visible and fluorometric chemodosimeter for hypochlorite

NASA Astrophysics Data System (ADS)

Xu, Xiu-xiu; Qian, Ying

2017-08-01

An aldoxime containing fluorescent probe based on vinylpydine-appended triphenylamine-BODIPY has been designed and used for hypochlorite detection. OX-PPA-BODIPY was developed by introducing an aldoxime group into the 2-position of BODIPY, which can be used for the detection of hypochlorite with a sharp color change from pink to green. The attachment of 4-vinylpyridine moiety to triphenylamine-BODIPY constructs a fluorogen with desirable conjugated system. The probe, which displays extremely weak fluorescence owing to the Cdbnd N isomerization mechanism at 2-position of BODIPY, responds to HClO/ClO- through a dramatic enhancement of its fluorescence intensity. This new probe, a naked-eye visible and fluorometric chemodosimeter, exhibits high selectivity and sensitivity toward hypochlorite over other reactive oxygen species (ROS) and anions. The detection is accompanied by a 20-fold increase in fluorescent intensity (ΦF from 0.02 to 0.43). The detection limit of the probe for hypochlorite is 7.37 × 10- 7 M. Moreover, OX-PPA-BODIPY can be used to detect hypochlorite in real water samples.

NO2/NO partitioning as a test of stratospheric ClO concentrations over Antarctica

NASA Technical Reports Server (NTRS)

Webster, Christopher R.

1987-01-01

Physical conditions in the 10-20 km region of the Antarctic stratosphere make the (NO2)/(NO) ratio particularly sensitive to high chlorine levels in the form of ClO. According to simple known photochemical relationships between NO2, NO, ClO, and O3, high ClO levels of 1 ppbv over Antarctica must be accompanied by large values of the (NO2)/(NO) ratio. At high ClO abundances, the (NO2)/(NO) ratio is approximately proportional to the ClO concentration. It is proposed that in-situ measurements of the (NO2)/(NO) ratio could be used to test the high chlorine hypothesis.

Development and validation of the first assay method coupling liquid chromatography with chemiluminescence for the simultaneous determination of menadione and its thioether conjugates in rat plasma.

PubMed

Elgawish, Mohamed Saleh; Shimomai, Chikako; Kishikawa, Naoya; Ohyama, Kaname; Wada, Mitsuhiro; Kuroda, Naotaka

2013-09-16

Menadione (2-methyl-1,4-naphthoquinone, MQ), a component of multivitamin drugs with antihemorrhagic, antineoplastic, and antimalarial activity, is frequently used to investigate quinone-induced cytotoxicity. The formation of MQ conjugates with glutathione (GSH) by Michael addition and subsequent biotransformation to yield N-acetyl-l-cysteine conjugates is believed to be an important detoxification process. However, the resulting conjugates, 2-methyl-3-(glutathione-S-yl)-1,4-naphthoquinone (MQ-GS) and 2-methyl-3-(N-acetyl-l-cysteine-S-yl)-1,4-naphthoquinone (MQ-NAC), retain the ability to redox cycle and to arylate cellular nucleophiles. Although the nephrotoxicity and hepatotoxicity of MQ-thiol conjugates have been reported in vitro, methods for their determination in vivo have yet to be published. Herein, a highly sensitive, simple, and selective HPLC-chemiluminescence (HPLC-CL) coupled method is reported, allowing for the first time the simultaneous determination of MQ, MQ-GS, and MQ-NAC in rat plasma after MQ administration. Our method exploits the unique redox characteristics of MQ, MQ-GS, and MQ-NAC to react with dithiothreitol (DTT) to liberate reactive oxygen species (ROS) which are detected by a CL assay using luminol as a CL probe. To verify the proposed mechanism, MQ-GS and MQ-NAC were synthetically prepared. Specimen preparation involved solid-phase extraction on an Oasis HLB cartridge followed by isocratic elution on an ODS column. No interference from endogenous substances was detected. Linearity was observed in the range of 5-120 nM for MQ-GS and MQ-NAC and 10-240 nM for MQ, with detection limits (S/N of 3) of 1.4, 0.8, and 128 fmol for MQ-GS, MQ-NAC, and MQ, respectively. The application of our method reported here is the first to extensively study the stability and reversibility of thiol-quinones.

Hydrogen gas improves left ventricular hypertrophy in Dahl rat of salt-sensitive hypertension.

PubMed

Matsuoka, Hiroki; Miyata, Seiko; Okumura, Nozomi; Watanabe, Takuya; Hashimoto, Katsunori; Nagahara, Miki; Kato, Kazuko; Sobue, Sayaka; Takeda, Kozue; Ichihara, Masatoshi; Iwamoto, Takashi; Noda, Akiko

2018-06-14

Hypertension is an important risk factor for death resulting from stroke, myocardial infarction, and end-stage renal failure. Hydrogen (H 2 ) gas protects against many diseases, including ischemia-reperfusion injury and stroke. The effects of H 2 on hypertension and its related left ventricular (LV) function have not been fully elucidated. The purpose of this study was to investigate the effects of H 2 gas on hypertension and LV hypertrophy using echocardiography. Dahl salt-sensitive (DS) rats were randomly divided into three groups: those fed an 8% NaCl diet until 12 weeks of age (8% NaCl group), those additionally treated with H 2 gas (8% NaCl + H 2 group), and control rats maintained on a diet containing 0.3% NaCl until 12 weeks of age (0.3% NaCl group). H 2 gas was supplied through a gas flowmeter and delivered by room air (2% hydrogenated room air, flow rate of 10 L/min) into a cage surrounded by an acrylic chamber. We evaluated interventricular septal wall thickness (IVST), LV posterior wall thickness (LVPWT), and LV mass using echocardiography. IVST, LVPWT, and LV mass were significantly higher in the 8% NaCl group than the 0.3% NaCl group at 12 weeks of age, whereas they were significantly lower in the 8% NaCl + H 2 group than the 8% NaCl group. There was no significant difference in systolic blood pressure between the two groups. Our findings suggest that chronic H 2 gas inhalation may help prevent LV hypertrophy in hypertensive DS rats.

Ultrastructural and biochemical evidence for the presence of mature steroidogenic acute regulatory protein (StAR) in the cytoplasm of human luteal cells.

PubMed

Sierralta, Walter D; Kohen, Paulina; Castro, Olga; Muñoz, Alex; Strauss, Jerome F; Devoto, Luigi

2005-10-20

The distribution of the steroidogenic acute regulatory protein (StAR) inside thecal and granulosa-lutein cells of human corpus luteum (CL) was assessed by immunoelectron microscopy. We found greater levels of StAR immunolabeling in steroidogenic cells from early- and mid-than in late luteal phase CL and lower levels in cells from women treated with a GnRH antagonist in the mid-luteal phase. Immunoelectron microscopy revealed significant levels of StAR antigen in the mitochondria and in the cytoplasm of luteal cells. The 30 kDa mature StAR protein was present in both mitochondria and cytosol (post-mitochondrial) fractions from homogenates of CL at different ages, whereas cytochrome c and mitochondrial HSP70 were detected only in the mitochondrial fraction. Therefore, we hypothesized that either appreciable processing of StAR 37 kDa pre-protein occurs outside the mitochondria, or mature StAR protein is selectively released into the cytoplasm after mitochondrial processing. The presence of mature StAR in the cytoplasm is consonant with the notion that StAR acts on the outer mitochondrial membrane to effect sterol import, and that StAR may interact with other cytoplasmic proteins involved in cholesterol metabolism, including hormone sensitive lipase.

Determination of sulpiride in pharmaceutical preparations and biological fluids using a Cr (III) enhanced chemiluminescence method.

PubMed

Khan, Muhammad Naeem; Jan, Muhammad Rasul; Shah, Jasmin; Lee, Sang Hak; Kim, Young Ho

2013-01-01

A highly sensitive and simple method for identifying sulpiride in pharmaceutical formulations and biological fluids is presented. The method is based on increased chemiluminescence (CL) intensity of a luminol-H2O2 system in response to the addition of Cr (III) under alkaline conditions. The CL intensity of the luminol-H2O2-Cr (III) system was greatly enhanced by the addition of sulpiride and the CL intensity was proportional to the concentration of sulpiride in a sample solution. Various parameters affecting the CL intensity were systematically investigated and optimized for determination of the sulpiride in a sample. Under the optimum conditions, the CL intensity was proportional to the concentration of sulpiride in the range of 0.068-4.0 µg/mL, with a good correlation coefficient of 0.997. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 8.50 × 10(-6) µg/mL and 2.83 × 10(-5) µg/mL, respectively. The method presented here produced good reproducibility with a relative standard deviation (RSD) of 2.70% (n = 7). The effects of common excipients and metal ions were studied for their interference effect. The method was validated statistically through recovery studies and successfully applied for the determination of sulpiride in pure form, pharmaceutical preparations and spiked human plasma samples. The percentage recoveries were found to range from 99.10 to 100.05% for pure form, 98.12 to 100.18% for pharmaceutical preparations and 97.9 to 101.4% for spiked human plasma. Copyright © 2012 John Wiley & Sons, Ltd.

A validated silver-nanoparticle-enhanced chemiluminescence method for the determination of citalopram in pharmaceutical preparations and human plasma.

PubMed

Khan, Muhammad Naeem; Jan, Muhammad Rasul; Shah, Jasmin; Lee, Sang Hak

2014-05-01

A simple and sensitive chemiluminescence (CL) method was developed for the determination of citalopram in pharmaceutical preparations and human plasma. The method is based on the enhancement of the weak CL signal of the luminol-H2 O2 system. It was found that the CL signal arising from the reaction between alkaline luminol and H2 O2 was greatly increased by the addition of silver nanoparticles in the presence of citalopram. Prepared silver nanoparticles (AgNPs) were characterized by UV-visible spectroscopy and transmission electron microscopy (TEM). Various experimental parameters affecting CL intensity were studied and optimized for the determination of citalopram. Under optimized experimental conditions, CL intensity was found to be proportional to the concentration of citalopram in the range 40-2500 ng/mL, with a correlation coefficient of 0.9997. The limit of detection (LOD) and limit of quantification (LOQ) of the devised method were 3.78 and 12.62 ng/mL, respectively. Furthermore, the developed method was found to have excellent reproducibility with a relative standard deviation (RSD) of 3.65% (n = 7). Potential interference by common excipients was also studied. The method was validated statistically using recovery studies and was successfully applied to the determination of citalopram in the pure form, in pharmaceutical preparations and in spiked human plasma samples. Percentage recoveries were found to range from 97.71 to 101.99% for the pure form, from 97.84 to 102.78% for pharmaceutical preparations and from 95.65 to 100.35% for spiked human plasma. Copyright © 2013 John Wiley & Sons, Ltd.

[Relationship between clinical symptoms and Hiragana reading ability in children with difficulties in reading and writing:usefulness of a clinical-symptoms-checklist].

PubMed

Kita, Yosuke; Kobayashi, Tomoka; Koike, Toshihide; Koeda, Tatsuya; Wakamiya, Eiji; Hosokawa, Torn; Kaga, Makiko; Inagaki, Masumi

2010-11-01

We investigated the clinical symptoms of children with developmental dyslexia (DD) and evaluated the relationship between these symptoms and their Hiragana reading abilities. In order to detect the clinical symptoms of DD, we newly developed a clinical-symptoms-checklist (CL), which consisted of a total of 30 yes/no questions regarding symptoms linked to reading (15 questions) and writing (15 questions). Subjects were 98 Japanese school grade (1 to 9) children, aged 6 to 15 years old, with normal intelligence confirmed by the Wechsler Intelligence Test for Children (WISC-Ill) and they were divided into 2 groups according to their diagnosis. Twenty four children diagnosed as developmental dyslexia consisted the DD group, and the remaining 74 children were grouped in the non-DD group. CL showed significant construct validity (p<0.05) and inner consistency (reading: a =0.82, writing: a =0.72) after deleting two questions from the originals. The number of questions checked in the CL reading subcategory significantly correlated with the Hiragana reading ability of articulation time in all Hiragana reading tasks (p<0.001). More severe clinical symptoms and lower reading ability were observed in the DD group compared to the non-DD group. Receiver Operating Characteristics (ROC) analysis indicated that these two groups could be discriminated by the CL and the results of the reading task, and both sensitivity and specificity rate were approximately 80%. It was suggested that 7 or more positive checks in the CL and 2 or more abnormal scores in the reading tasks might discriminate DD from other conditions which cause difficulties in reading and writing in Japanese children.

W{sub 18}O{sub 49} nanorods decorated with Ag/AgCl nanoparticles as highly-sensitive gas-sensing material and visible-light-driven photocatalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun Shibin; Chang Xueting, E-mail: xuetingchang@yahoo.cn; Dong Lihua

2011-08-15

A novel gas-sensing material and photocatalyst was successfully obtained by decorating Ag/AgCl nanoparticles on the W{sub 18}O{sub 49} nanorods through a clean photochemical route. The as-prepared samples were characterized using combined techniques of X-ray diffractometry, electron microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. Gas-sensing measurements indicate that the Ag/AgCl/W{sub 18}O{sub 49} NRs sensors exhibit superior reducing gas-sensing properties to those of bare W{sub 18}O{sub 49} NRs, and they are highly selective and sensitive to NH{sub 3}, acetone, and H{sub 2}S with short response and recovery times. The Ag/AgCl/W{sub 18}O{sub 49} NRs photocatlysts also possess higher photocatalytic performance thanmore » bare W{sub 18}O{sub 49} NRs for degradation of methyl orange under simulated sunlight irradiation. Possible mechanisms concerning the enhancement of gas-sensing and photocatalytic activities of the Ag/AgCl/W{sub 18}O{sub 49} NRs composite were proposed. - Graphical Abstract: The Ag/AgCl nanoparticles adhered well to the W{sub 18}O{sub 49} nanorod. The Ag could act as transfer center of the photoexcited carriers, prohibiting their recombinations in both W{sub 18}O{sub 49} and AgCl. Highlights: > Ag/AgCl/W{sub 18}O{sub 49} NRs were successfully obtained via a clean photochemical route. > The Ag/AgCl nanoparticles decorated on the W{sub 18}O{sub 49} NRs possessed cladding structure. > The Ag/AgCl/W{sub 18}O{sub 49} NRs exhibited excellent gas-sensing and photocatalytic properties.« less

Passive potassium transport in low potassium sheep red cells: dependence upon cell volume and chloride.

PubMed Central

Dunham, P B; Ellory, J C

1981-01-01

The major pathway of passive K influx (ouabain-insensitive) was characterized in low-K type (LK) red cells of sheep. 1. Passive K transport in these cells was highly sensitive to variations in cell volume; it increased threefold or more in cells swollen osmotically by 10%, and decreased up to twofold in cells shrunken 5-10%. Active K influx was insensitive to changes in cell volume. Three different methods for varying cell volume osmotically all gave similar results. 2. The volume-sensitive pathway was specific for K in that Na influx did not vary with changes in cell volume. 3. The volume-sensitive K influx was a saturable function of external K concentration. It was slightly inhibited by Na, whereas K influx in shrunken cells was unaffected by Na. 4. Passive K influx was dependent on the major anion in the medium in that replacement of Cl with any of six other anions resulted in a reduction of K influx by 50-80% (replacement of Cl by Br caused an increase in K influx). The activation of K influx by Cl followed sigmoid kinetics. 5. Passive K influx is inhibited by anti-L antibody. The antibody affected only that portion of influx which was Cl-dependent and volume-sensitve. Of the subfractions of the antibody, it is anti-L1 which inhibits passive K transport. 6. Pretreatment of cells with iodoacetamide reduced the sensitivity of K influx to cell volume in that the influx was reduced in swollen IAA-treated cells and increased in shrunken IAA-cells. 7. Intracellular Ca has no role in altering passive K transport in LK sheep cells. Therefore, the major pathway of passive K transport in LK sheep red cells is sensitive to changes in cell volume, specific for K, dependent on Cl, and inhibited by anti-L1 antibody, The minor pathway, observed in shrunken cells, has none of these properties. PMID:6798197

Highly sensitive luminol electrochemiluminescence immunosensor based on ZnO nanoparticles and glucose oxidase decorated graphene for cancer biomarker detection.

PubMed

Cheng, Yinfeng; Yuan, Ruo; Chai, Yaqin; Niu, Huan; Cao, Yaling; Liu, Huijing; Bai, Lijuan; Yuan, Yali

2012-10-01

In this work, we reported a sandwiched luminol electrochemiluminescence (ECL) immunosensor using ZnO nanoparticles (ZnONPs) and glucose oxidase (GOD) decorated graphene as labels and in situ generated hydrogen peroxide as coreactant. In order to construct the base of the immunosensor, a hybrid architecture of Au nanoparticles and graphene by reduction of HAuCl(4) and graphene oxide (GO) with ascorbic acid was prepared. The resulted hybrid architecture modified electrode provided an excellent platform for immobilization of antibody with good bioactivity and stability. Then, ZnONPs and GOD functionalized graphene labeled secondary antibody was designed for fabricating a novel sandwiched ECL immunosensor. Enhanced sensitivity was obtained by in situ generating hydrogen peroxide with glucose oxidase and the catalysis of ZnONPs to the ECL reaction of luminol-H(2)O(2) system. The as-prepared ECL immunosensor exhibited excellent analytical property for the detection of carcinoembryonic antigen (CEA) in the range from 10 pg mL(-1) to 80 ng mL(-1) and with a detection limit of 3.3 pg mL(-1) (SN(-1)=3). The amplification strategy performed good promise for clinical application of screening of cancer biomarkers. Copyright © 2012 Elsevier B.V. All rights reserved.

Amorphous Ni(OH)2/CQDs microspheres for highly sensitive non-enzymatic glucose detection prepared via CQDs induced aggregation process

NASA Astrophysics Data System (ADS)

Zhu, Jiajie; Yin, Haoyong; Cui, Zhenzhen; Qin, Dongyu; Gong, Jianying; Nie, Qiulin

2017-10-01

Non-enzymatic electrochemical sensors for the detection of glucose were designed based on amorphous Ni(OH)2/CQDs microspheres. The amorphous Ni(OH)2/CQDs microspheres were prepared by a CQDs assistant crystallization inhibition process. The morphologies and composition of the microspheres were characterized by SEM, TEM, XRD, EDS, and TG/DSC. The results showed that the microspheres had uniform heterogeneous phases with amorphous Ni(OH)2 and CQDs. The sensor based on amorphous Ni(OH)2/CQDs microspheres showed remarkable electrocatalytic activity towards glucose oxidation comparing to the conventional crystalline Ni(OH)2, which included two linear range (20 μM-350 μM and 0.45mM-2.5 mM) with high selectivity of 2760.05 and 1853.64 μA mM-1cm-2. Moreover, the interference from the commonly interfering species such as urea, ascorbic acid, NaCl, L-proline and L-Valine, can be effectively avoided. The high sensitivity, wide glucose detection range and good selectivity of the electrode may be due to their synergistic effect of amorphous phase and CQDs incorporation. These findings may promote the application of amorphous Ni(OH)2 as advanced electrochemical glucose sensing materials.

Simple flow injection for determination of sulfite by amperometric detection using glassy carbon electrode modified with carbon nanotubes-PDDA-gold nanoparticles.

PubMed

Amatatongchai, Maliwan; Sroysee, Wongduan; Chairam, Sanoe; Nacapricha, Duangjai

2015-02-01

A new approach is presented for sensitive and selective measurement of sulfite (SO3(2-)) in beverages based on a simple flow injection system with amperometric detection. In this work, the sulfite sensor was a glassy carbon electrode modified with multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-gold nanoparticles composites (CNTs-PDDA-AuNPs/GC). Electrochemical oxidation of sulfite with this electrode was first studied in 0.1M phosphate buffer (pH 7.0) using cyclic voltammetry. The results indicated that the CNTs-PDDA-AuNPs/GC electrode possesses electrocatalytic activity for the oxidation of sulfite with high sensitivity and selectivity. Sulfite was quantified using amperometric measurement with the new sensor at +0.4V vs Ag/AgCl in conjunction with flow injection. The linear working range for the quantitation of sulfite was 2-200 mg L(-1) (r(2)=0.998) with a detection limit of 0.03 mg L(-1) (3σ of blank) and an estimated precision of 1.5%.The proposed method was successfully applied to the determination of sulfite in fruit juices and wines with a sample throughput of 23 samples per hour. Copyright © 2014 Elsevier B.V. All rights reserved.

Carbon Nanotube-Based Ion Selective Sensors for Wearable Applications.

PubMed

Roy, Soumyendu; David-Pur, Moshe; Hanein, Yael

2017-10-11

Wearable electronics offer new opportunities in a wide range of applications, especially sweat analysis using skin sensors. A fundamental challenge in these applications is the formation of sensitive and stable electrodes. In this article we report the development of a wearable sensor based on carbon nanotube (CNT) electrode arrays for sweat sensing. Solid-state ion selective electrodes (ISEs), sensitive to Na + ions, were prepared by drop coating plasticized poly(vinyl chloride) (PVC) doped with ionophore and ion exchanger on CNT electrodes. The ion selective membrane (ISM) filled the intertubular spaces of the highly porous CNT film and formed an attachment that was stronger than that achieved with flat Au, Pt, or carbon electrodes. Concentration of the ISM solution used influenced the attachment to the CNT film, the ISM surface morphology, and the overall performance of the sensor. Sensitivity of 56 ± 3 mV/decade to Na + ions was achieved. Optimized solid-state reference electrodes (REs), suitable for wearable applications, were prepared by coating CNT electrodes with colloidal dispersion of Ag/AgCl, agarose hydrogel with 0.5 M NaCl, and a passivation layer of PVC doped with NaCl. The CNT-based REs had low sensitivity (-1.7 ± 1.2 mV/decade) toward the NaCl solution and high repeatability and were superior to bare Ag/AgCl, metals, carbon, and CNT films, reported previously as REs. CNT-based ISEs were calibrated against CNT-based REs, and the short-term stability of the system was tested. We demonstrate that CNT-based devices implemented on a flexible support are a very attractive platform for future wearable technology devices.

Growth and cellular ion content of a salt-sensitive symbiotic system Azolla pinnata-Anabaena azollae under NaCl stress.

PubMed

Rai, Vandna; Sharma, Naveen Kumar; Rai, Ashwani K

2006-09-01

Salinity, at a concentration of 10 mM NaCl affected the growth of Azolla pinnata-Anabaena azollae association and became lethal at 40 mM. Plants exposed up to 30 mM NaCl exhibited longer roots than the control, especially during the beginning of incubation. Average root number in plants exposed to 10 and 20 mM NaCl remained almost the same as in control. A further rise in NaCl concentration to 30 mM reduced the root number, and roots shed off at 40 mM NaCl. Presence of NaCl in the nutrient solution increased the cellular Na+ of the intact association exhibiting differential accumulation by individual partners, while it reduced the cellular Ca2+ level. However, cellular K+ content did not show significant change. Cellular Na+ based on fresh weight of respective individual partners (host tissues and cyanobiont) remained higher in the host tissues than the cyanobiont, while reverse was true for K+ and Ca2+ contents. The contribution of A. azollae in the total cellular ion content of the association was a little because of meagre contribution of the cyanobiont mass (19-21%). High salt sensitivity of Azolla-Anabaena complex is due to an inability of the association to maintain low Na+ and high Ca2+ cellular level.

HV1 acts as a sodium sensor and promotes superoxide production in medullary thick ascending limb of Dahl salt-sensitive rats.

PubMed

Jin, Chunhua; Sun, Jingping; Stilphen, Carly A; Smith, Susan M E; Ocasio, Hiram; Bermingham, Brent; Darji, Sandip; Guha, Avirup; Patel, Roshan; Geurts, Aron M; Jacob, Howard J; Lambert, Nevin A; O'Connor, Paul M

2014-09-01

We previously characterized a H(+) transport pathway in medullary thick ascending limb nephron segments that when activated stimulated the production of superoxide by nicotinamide adenine dinucleotide phosphate oxidase. Importantly, the activity of this pathway was greater in Dahl salt-sensitive rats than salt-resistant (SS.13(BN)) rats, and superoxide production was enhanced in low Na(+) media. The goal of this study was to determine the molecular identity of this pathway and its relationship to Na(+). We hypothesized that the voltage-gated proton channel, HV1, was the source of superoxide-stimulating H(+) currents. To test this hypothesis, we developed HV1(-/-) null mutant rats on the Dahl salt-sensitive rat genetic background using zinc-finger nuclease gene targeting. HV1 could be detected in medullary thick limb from wild-type rats. Intracellular acidification using an NH4Cl prepulse in 0 sodium/BaCl2 containing media resulted in superoxide production in thick limb from wild-type but not HV1(-/-) rats (P<0.05) and more rapid recovery of intracellular pH in wild-type rats (ΔpHI 0.005 versus 0.002 U/s, P=0.046, respectively). Superoxide production was enhanced by low intracellular sodium (<10 mmol/L) in both thick limb and peritoneal macrophages only when HV1 was present. When fed a high-salt diet, blood pressure, outer medullary renal injury (tubular casts), and oxidative stress (4-hydroxynonenal staining) were significantly reduced in HV1(-/-) rats compared with wild-type Dahl salt-sensitive rats. We conclude that HV1 is expressed in medullary thick ascending limb and promotes superoxide production in this segment when intracellular Na(+) is low. HV1 contributes to the development of hypertension and renal disease in Dahl salt-sensitive rats. © 2014 American Heart Association, Inc.

Determination of NH(3) gas by combination of nanosized LaCoO(3) converter with chemiluminescence detector.

PubMed

Shi, Jinjun; Yan, Ruoxue; Zhu, Yongfa; Zhang, Xinrong

2003-10-17

Combination of a novel NH(3) converter based on nanosized materials with chemiluminescence (CL) detector for the determination of NH(3) gas was demonstrated in this paper. NH(3) gas is oxidized on different nanosized catalysts to produce NO(x), which can react with luminol to generate CL emission. Eight nanosized materials were investigated as catalyst, and CL was detected from seven of them. The nanosized LaCoO(3) was chosen as the catalyst for preparing the converter because of its higher activity than others. Under the optimized conditions, the linear range of CL intensity versus concentration of NH(3) gas is 0.04-10 ppm (r=0.9951, n=14) with the detection limit of 0.014 ppm. The method offers advantages of long lifetime of the converter, fast response and high selectivity to NH(3). There was no response while the foreign substances, such as hydrogen, oxygen, nitrogen, formaldehyde, acetone and gasoline passing through the CL detection system, and the interference of CCl(4), ethanol, ethylene and toluene was insignificant.

GdCl3 reduces hyperglycaemia through Akt/FoxO1-induced suppression of hepatic gluconeogenesis in Type 2 diabetic mice.

PubMed

Wang, Qian; Wang, Ning; Dong, Mei; Chen, Fang; Li, Zhong; Chen, Yuanyuan

2014-07-01

GdCl3 (gadolinium chloride) has been shown to reduce blood glucose; however, the underlying mechanism remains unclear. Liver gluconeogenesis is an important pathway involved in the maintenance of glucose homoeostasis. The aim of the present study was to investigate the role of GdCl3 in hepatic gluconeogenesis and explore the precise molecular mechanism. Animals from a classical Type 2 diabetic mouse model, created by exposing C57BL/6J mice to a high-fat diet for 4 months, were treated with GdCl3 or saline. Body weight, blood glucose and insulin sensitivity were monitored. It was observed that GdCl3 significantly reduced blood glucose levels and improved insulin sensitivity. A pyruvate tolerance test showed further that GdCl3 suppressed gluconeogenesis in diabetic mice. In the livers of GdCl3-treated mice, the expression of Pepck (phosphoenolpyruvate carboxykinase) and G6pase (glucose-6-phosphatase), the key enzymes in gluconeogenesis, were dramatically reduced. Furthermore, experiments in hepatocarcinoma cells revealed that GdCl3 activated the Akt pathway to promote the phosphorylation of FoxO1 (forkhead box O1), leading to the suppression of gluconeogenesis by reducing the expression of PEPCK and G6Pase and resulting in decreased cellular production of glucose. Comparable results were observed in the livers of GdCl3-treated mice. In addition, we have shown that GdCl3 augmented the role of insulin to control hepatic glucose production. We conclude that GdCl3 reduces hyperglycaemia via the Akt/FoxO1-induced suppression of hepatic gluconeogenesis, both in Type 2 diabetic mice (in vivo) and in hepatocarcinoma cells (in vitro), suggesting that GdCl3 may be a potential therapeutic agent for diabetes.

Behavior of new complexes of tetrakis(4-methoxylphenyl)porphyrin with heavy rare earth elements in reversed-phase high performance liquid chromatography.

PubMed

Zhang, Jun-Feng; Wang, Hong; Hou, An-Xin; Wang, Chang-Fa; Zhang, Hua-Shan

2004-08-01

An HPLC method has been developed for the separation of new complexes of tetrakis(4-methoxylphenyl)porphyrin (TMOPP) with four heavy rare earth elements (RE = Y, Er, Tm, and Yb). The function of amine and acid in the mobile phase has been investigated and a reasonable explanation is presented. Successful separation of the RE-TMOPP-Cl complexes is accomplished in 10 min with a mobile phase consisting of methanol-water-acetic acid-triethanolamine. The detection limits (S/N= 3) for the four complexes are 0.01 microg/mL. This method is rapid, sensitive, and simple.

Clinical applications of gas chromatograph/mass spectrometer/computer systems.

PubMed

Horning, M G; Nowlin, J; Butler, C M; Lertratanangkoon, K; Sommer, K; Hill, R M

1975-08-01

Gas chromatograph/mass spectrometer/computer systems can be used to quantify a wide variety of compounds of clinical interest. A quadrupole instrument operated in the chemical ionization (Cl) mode was used in these studies. Because of the sensitivity and specificity of selective ion detection, it is possible to make measurements routinely in the nanogram to picogram range, with 0.1-1.0 ml samples of plasma and 1-5 ml samples or urine. Internal standards, preferably stable-isotope-labeled compounds, were added to the biological samples before isolation was begun. We describe clinical applications of these procedures to problems in toxicology, pharmacokinetics, and perinatal pharmacology.

Various Recrystallizations of CL-20 (HNIW hexanitrohexaazaisowurtzitane).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, Jason Joe

Impact sensitivity testing was performed using a modified Bureau of Mines (MBOM) impactor manufactured by Safety Management Services, Inc., shown in Figure 1. Type-12 tooling was utilized on this machine with a 2.5kg impactor and matching intermediate mass. This particular machine is capable of a maximum drop height of 115cm with 0.1cm increments, though 1cm increments are typically used. Sample material was placed (35 ± 2mg) onto 1 inch squares of Norton brand 180A Garnet sandpaper. Positive results were detected visually or audibly by the operator as smoke, flash, report, charring/tearing of the sandpaper, etc.

Is there any chlorine monoxide in the stratosphere?

NASA Technical Reports Server (NTRS)

Rogers, J. D.; Mumma, M. J.; Kostiuk, T.; Deming, D.; Hillman, J. J.; Faris, J.; Zipoy, D.

1982-01-01

A ground based search for the 856.50137/cm R(9.5) and for the 859.76765 R(12.5) transitions of stratospheric (Cl-35)O was made in the solar absorption mode using an infrared heterodyne spectrometer. Lines due to stratospheric HNO3 and tropospheric OCS were detected, at about 0.3% absorption levels. The expected lines of ClO in this same region were not detected, even though the optical depth of the ClO lines should be on the order of 0.2% using currently accepted ClO abundances. These infrared measurements suggest that stratospheric ClO is at least a factor of 7 less abundant than is indicated by indirect in situ fluorescence measurements, and the upper limit of 2.4x10 to the 13th power molecules/sq cm to the integrated column density of ClO is a factor of over 4 less than is indicted by microwave measurements. Results imply that the release of fluorocarbon precursors of ClO may be significantly less important for the destruction of stratospheric ozone than was previously thought.

Synthesis of silver/silver chloride/graphene oxide composite and its surface-enhanced Raman scattering activity and self-cleaning property

NASA Astrophysics Data System (ADS)

Zhao, Nan; Fei, Xiao; Cheng, Xiaonong; Yang, Juan

2017-09-01

Recently, silver nanoparticles decorated with graphene and graphene oxide (GO) sheets can be employed as surface-enhanced Raman scattering (SERS) substrates. However, their SERS activity on macromolecular compound detection is all one-time process. In order to solve this issue and decrease the cost of routine SERS detection, silver/silver chloride (Ag/AgCl) with photocatalytic activity under visible light was introduced. In this study, a novel, simple and clean approach is carried out for synthesis of the Ag/AgCl/GO composite. The Ag/AgCl colloidal solution is obtained by hydrothermal method and then mixed with GO solution to obtain the Ag/AgCl/GO composite using a facile electrostatic self-assembly method. Results showed that the Ag/AgCl/GO composite has the optimized SERS activity to Rhodamine 6G molecules with the maximum enhancement factor value of 3.8×107. Furthermore, the Ag/AgCl particles with high efficient and stable photocatalytic activity under visible light lead to an outstanding self-cleaning property of the Ag/AgCl/GO composite.

Confocal filtering in cathodoluminescence microscopy of nanostructures

NASA Astrophysics Data System (ADS)

Narváez, Angela C.; Weppelman, I. Gerward C.; Moerland, Robert J.; Hoogenboom, Jacob P.; Kruit, Pieter

2014-06-01

Cathodoluminescence (CL) microscopy allows optical characterization of nanostructures at high spatial resolution. At the nanoscale, a main challenge of the technique is related to the background CL generated within the sample substrate. Here, we implement confocal detection of the CL signal to minimize the background contribution to the measurement. Nano-phosphors were used as point sources to evaluate the filtering capabilities of our confocal CL system, obtaining an axial intensity profile with 2.7 μm full width at half maximum for the central peak, in good correspondence with theoretical expectations. Considering the electron interaction volume, we found that the confocal filter becomes effective for electron energies above 20 keV, when using a 25 μm pinhole (0.86 Airy units). To illustrate our approach, we present confocal CL imaging of gold nanowires and triangular shaped plates deposited on an indium-tin oxide covered glass substrate, comparing the images with those obtained in standard unfiltered CL detection. The results show that confocal CL microscopy is a valuable tool for the investigation of nanostructures on highly cathodoluminescent substrates, widely used in biological and optical applications.

Concentrations of cysteinyl leukotrienes in urine and bronchoalveolar lavage fluid of cats with experimentally induced asthma.

PubMed

Norris, Carol R; Decile, Kendra C; Berghaus, Londa J; Berghaus, Roy D; Walby, William F; Schelegle, Edward S; Hyde, Dallas M; Gershwin, Laurel J

2003-11-01

To evaluate changes in cysteinyl leukotriene (LT) concentrations in urine and bronchoalveolar lavage fluid (BALF) in cats with experimentally induced asthma. 19 cats with experimentally induced asthma and 5 control cats. Cats were sensitized to Bermuda grass or house dust mite allergen, and phenotypic features of asthma were confirmed with intradermal skin testing, evaluation of BALF eosinophil percentages, and pulmonary function testing. A competitive ELISA kit for LTC4, LTD4, and LTE4 was used for quantitative analysis of LTs. Urinary creatinine concentrations and BALF total protein (TP) concentrations were measured, and urinary LT-to-creatinine ratios and BALF LT-to-TP ratios were calculated. Mean urinary LT-to-creatinine ratios did not differ significantly between control cats and allergen-sensitized cats before or after sensitization and challenge exposure with saline (0.9% NaCl) solution or allergen, respectively. In BALF the mean LT-to-TP ratio of control cats did not differ significantly before or after sensitization and challenge exposure with saline. Asthmatic cats had BALF LT-to-TP ratios that were significantly lower than control cats at all time points, whereas ratios for asthmatic cats did not differ significantly among the various time points. Although LTs were readily detectable in urine, no significant increases in urinary LT concentrations were detected after challenge in allergen-sensitized cats. Spot testing of urinary LT concentrations appears to have no clinical benefit for use in monitoring the inflammatory asthmatic state in cats. The possibility that cysteinyl LTs bind effectively to their target receptors in BALF and, thus, decrease free LT concentrations deserves further study.

Gold nanoparticles hosted in a water-soluble silsesquioxane polymer applied as a catalytic material onto an electrochemical sensor for detection of nitrophenol isomers.

PubMed

Silva, Paulo Sérgio da; Gasparini, Bianca C; Magosso, Hérica A; Spinelli, Almir

2014-05-30

The water-soluble 3-n-propyl-4-picolinium silsesquioxane chloride (Si4Pic(+)Cl(-)) polymer was prepared, characterized and used as a stabilizing agent for the synthesis of gold nanoparticles (nAu). The ability of Si4Pic(+)Cl(-) to adsorb anionic metal complexes such as AuCl4(-) ions allowed well-dispersed nAu to be obtained with an average particle size of 4.5nm. The liquid suspension of nAu-Si4Pic(+)Cl(-) was deposited by the drop coating method onto a glassy carbon electrode (GCE) surface to build a sensor (nAu-Si4Pic(+)Cl(-)/GCE) which was used for the detection of o-nitrophenol (o-NP) and p-nitrophenol (p-NP). Under optimized experimental conditions the reduction peak current increased with increasing concentrations of both nitrophenol isomers in the range of 0.1-1.5μmolL(-1). The detection limits were 46nmolL(-1) and 55nmolL(-1) for o-NP and p-NP, respectively. These findings indicate that the nAu-Si4Pic(+)Cl(-) material is a very promising candidate to assemble electrochemical sensors for practical applications in the field of analytical chemistry. Copyright © 2014 Elsevier B.V. All rights reserved.

AMS Measurement of 36Cl with a Q3D Magnetic Spectrometer at CIAE

NASA Astrophysics Data System (ADS)

Li, Chaoli; He, Ming; Zhang, Wei; Wu, Shaoyong; Li, Zhenyu; He, Xianwen; Liu, Jiancheng; Dong, Kejun; Jiang, Shan

2012-06-01

The ratio of 36Cl/Cl can determine the exposure age of surface rocks and monitor the secular equilibrium of 36Cl of sedimentary and igneous rock in groundwater. Due to the uncertainty effects of different chemical separation processes for removing 36S, there is a high degree of uncertainty in 36Cl accelerator mass spectrometry (AMS) measurements if the ratio of 36Cl/Cl is lower than 10-14. A 36Cl AMS higher sensitivity measurement has been set up by using a ΔE-Q3D method at the China Institute of Atomic Energy (CIAE). The performances of ΔE-Q3D method for 36Cl-AMS measurement had been systemically studied. The experimental results show that the ΔE-Q3D method has a higher isobar suppression factor. Taking advantage of direct removing 36S, the sample preparation can be simplified and the uncertainty effects of different chemical separation processes can be reduced in 36Cl AMS measurements.

Mechanisms of zinc transport into pig small intestine brush-border membrane vesicles.

PubMed Central

Tacnet, F; Lauthier, F; Ripoche, P

1993-01-01

1. The purpose of the present work was to examine certain membrane transport mechanisms likely to carry zinc across the brush-border membrane of pig small intestine, isolated in a vesicular form. 2. In initial velocity conditions, saturation kinetics revealed a great effect of pH on zinc transport: optimal conditions were observed with an intravesicular pH of around 6.6 with or without a H+ gradient; however, this did not allow us to conclude the existence of a neutral exchange between Zn2+ and H+ ions. 3. By measuring 36Cl uptakes, the presence of the Cl(-)-HCO3- or Cl(-)-OH-antiporter with typical 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) sensitivity was detected in vesicles; zinc did not alter this anionic exchange activity. A 65Zn time course, performed in conditions identical with those for 36Cl uptake, was DIDS insensitive and was greatly inhibited by an outward OH- gradient. This could argue against a transport of zinc as a complex with Cl- and HCO3- through the anion antiporter. 4. When external Cl- and HCO3- were replaced by SCN-, able to form a Zn(SCN)4(2-) complex, we observed a stimulating effect of outward HCO3- gradients on 65Zn uptake but neither DIDS nor diphenylamine-2-carboxylate (DPC) inhibited the transport in these conditions. This suggested that the intestinal anion antiporter was not a major route for zinc reabsorption. 5. The tripeptide Gly-Gly-His at low concentrations stimulated 65Zn uptake, then inhibited it in a dose-dependent manner either in the presence of an inward H+ gradient or in the presence of a membrane potential 'negative inside' or in both situations. These conditions are necessary for the active transport of the peptide and this strongly suggests that zinc can be transported as a [Gly-Gly-His-Zn] complex, utilizing the peptide carrier system. PMID:8229851

Coupling Molecular Beacons to Barcoded Metal Nanowires for Multiplexed, Sealed Chamber DNA Bioassays

PubMed Central

Stoermer, Rebecca L.; Cederquist, Kristin B.; McFarland, Sean K.; Sha, Michael Y.; Penn, Sharron G.

2010-01-01

We have combined molecular beacon (MB) probes with barcoded metal nanowires to enable no-wash, sealed chamber, multiplexed detection of nucleic acids. Probe design and experimental parameters important in nanowire-based MB assays are discussed. Loop regions of 24 bases and 5 base pair stem regions in the beacon probes gave optimal performance. Our results suggest that thermodynamic predictions for secondary structure stability of solution-phase MB can guide probe design for nanowire-based assays. Dengue virus-specific probes with predicted solution-phase ΔG of folding in 500 mM buffered NaCl of approximately −4 kcal/mol performed better than those with ΔG > −2 or < −6 kcal/mol. Buffered 300–500 mM NaCl was selected after comparison of several buffers previously reported for similar types of assays, and 200–500 mM NaCl was found to be the optimal ionic strength for the hybridization temperatures (25 and 50 °C) and probe designs used here. Target binding to the surface as a function of solution concentration fit a Sips isotherm with Kd = 1.7 ± 0.3 nM. The detection limit was ∼100 pM, limited by incomplete quenching. Single base mismatches could be discriminated from fully complementary targets. Oligonucleotide target sequences specific for human immunodeficiency, hepatitis C, and severe acute respiratory viruses were assayed simultaneously in a no-wash, sealed chamber, multiplexed experiment in which each of three probe sequences was attached to a different pattern of encoded nanowires. Finally, we demonstrated that probe-coated nanowires retain their selectivity and sensitivity in a triplexed assay after storage for over 3 months. PMID:17177440

Two New Real-Time PCR-based Surveillance Systems for “Candidatus Liberibacter” Species Detection

USDA-ARS?s Scientific Manuscript database

We developed two novel surveillance systems for “Candidatus Liberibacter” (CL) species detection and identification. The first system is called “single tube dual primer Taq-Man PCR” (STDP). The procedure involves two sequential rounds of PCR using the CL asiaticus species-specific outer and inner pr...

Redox hydrogel based bienzyme electrode for L-glutamate monitoring.

PubMed

Belay, A; Collins, A; Ruzgas, T; Kissinger, P T; Gorton, L; Csöregi, E

1999-02-01

Amperometric bienzyme electrodes based on coupled L-glutamate oxidase (GlOx) and horseradish peroxidase (HRP) were constructed for the direct monitoring of L-glutamate in a flow injection (FI)-system. The bienzyme electrodes were constructed by coating solid graphite rods with a premixed solution containing GlOx and HRP crosslinked with a redox polymer formed of poly(1-vinylimidazole) complexed with (osmium (4-4'-dimethylbpy)2 Cl)II/III. Poly(ethylene glycol) diglycidyl ether (PEGDGE) was used as the crosslinker and the modified electrodes were inserted as the working electrode in a conventional three electrode flow through amperometric cell operated at -0.05 V versus Ag¿AgCl (0.1 M KCl). The bienzyme electrode was optimized with regard to wire composition, Os-loading of the wires, enzyme ratios, coating procedure, flow rate, effect of poly(ethyleneimine) addition, etc. The optimized electrodes were characterized by a sensitivity of 88.36 +/- 0.14 microA mM(-1) cm(-2), a detection limit of 0.3 microM (calculated as three times the signal-to-noise ratio), a response time of less than 10 s and responded linearly between 0.3 and 250 microM (linear regression coefficient = 0.999) with an operational stability of only 3% sensitivity loss during 8 h of continuous FI operation at a sample throughput of 30 injections h(-1).

Controlled drug-release system based on pH-sensitive chloride-triggerable liposomes.

PubMed

Wehunt, Mark P; Winschel, Christine A; Khan, Ali K; Guo, Tai L; Abdrakhmanova, Galya R; Sidorov, Vladimir

2013-03-01

New pH-sensitive lipids were synthesized and utilized in formulations of liposomes suitable for controlled drug release. These liposomes contain various amounts of NaCl in the internal aqueous compartments. The release of the drug model is triggered by an application of HCl cotransporter and exogenous physiologically relevant NaCl solution. HCl cotransporter allows an uptake of HCl by liposomes to the extent of their being proportional to the transmembrane Cl(-) gradient. Therefore, each set of liposomes undergoes internal acidification, which, ultimately, leads to the hydrolysis of the pH-sensitive lipids and content release at the desired time. The developed system releases the drug model in a stepwise fashion, with the release stages separated by periods of low activity. These liposomes were found to be insensitive to physiological concentrations of human serum albumin and to be nontoxic to cells at concentrations exceeding pharmacological relevance. These results render this new drug-release model potentially suitable for in vivo applications.

Effects of sodium chloride exposure on ion regulation in larvae (glochidia) of the freshwater mussel Lampsilis fasciola.

PubMed

Nogueira, Lygia S; Bianchini, Adalto; Wood, Chris M; Loro, Vania L; Higgins, Sarah; Gillis, Patricia L

2015-12-01

The salinization of freshwater can have negative effects on ecosystem health, with heightened effects in salt-sensitive biota such as glochidia, the larvae of freshwater mussels. However, the toxicological mechanism underlying this sensitivity is unknown. Therefore, Lampsilis fasciola glochidia were exposed to NaCl (nominally 0.25 and 1.0 g/L) prepared in reconstituted moderately-hard water (control), as well as to a dilution of that water (1:4) with ultrapure reference water (diluted control). Unidirectional Na(+) influx (measured with (22)Na) was evaluated after 1, 3 and 48 h of exposure. In addition, unidirectional Cl(-) influx (measured with (36)Cl), whole-body ion (Cl(-) and Na(+)) concentrations, and glochidia viability (measured as the ability to close valves) were assessed after 48 h of exposure. Significantly reduced glochidia viability (56%) was observed after exposure to 1.0 g/L NaCl. Na(+) influx was significantly higher in glochidia exposed to both 0.25 and 1.0 g/L NaCl for 1h than in those kept under control conditions. After 3 and 48 h of exposure, differences in Na(+) influx rate between salt-exposed and control glochidia were generally reduced, indicating that larvae may be able to, at least temporarily, recover their ability to regulate Na(+) influx when exposed to elevated NaCl concentration. Compared to the moderately-hard water control, whole-body Na(+) and Cl(-) concentrations were relatively unchanged in glochidia exposed to 0.25 g/L NaCl, but were significantly elevated in glochidia exposed to 1.0 g/L NaCl and the diluted control. While Na(+) influx rate had recovered to the control level after 48 h of exposure to 1.0 g/L NaCl, Cl(-) influx rate remained elevated, being ~7-fold higher than the Na(+) influx rate. These findings suggest that the loss of viability observed when glochidia were exposed to a high NaCl concentration (1.0 g/L) could be caused by ionoregulatory disturbances mainly associated with an elevated Cl(-) influx. Copyright © 2015 Elsevier Inc. All rights reserved.

Coherence factors in a high-tc cuprate probed by quasi-particle scattering off vortices.

PubMed

Hanaguri, T; Kohsaka, Y; Ono, M; Maltseva, M; Coleman, P; Yamada, I; Azuma, M; Takano, M; Ohishi, K; Takagi, H

2009-02-13

When electrons pair in a superconductor, quasi-particles develop an acute sensitivity to different types of scattering potential that is described by the appearance of coherence factors in the scattering amplitudes. Although the effects of coherence factors are well established in isotropic superconductors, they are much harder to detect in their anisotropic counterparts, such as high-superconducting-transition-temperature cuprates. We demonstrate an approach that highlights the momentum-dependent coherence factors in Ca2-xNaxCuO2Cl2. We used Fourier-transform scanning tunneling spectroscopy to reveal a magnetic-field dependence in quasi-particle scattering interference patterns that is sensitive to the sign of the anisotropic gap. This result is associated with the d-wave coherence factors and quasi-particle scattering off vortices. Our technique thus provides insights into the nature of electron pairing as well as quasi-particle scattering processes in unconventional superconductors.

Evaluation of a new rapid diagnostic test for the detection of influenza and RSV.

PubMed

Gómez, Sara; Prieto, Columbiana; Vera, Carmen; R Otero, Joaquín; Folgueira, Lola

2016-05-01

Influenza viruses and respiratory syncytial virus (RSV) can cause an acute respiratory disease that occurs seasonally in epidemic waves. This retrospective study was conducted to evaluate the Sofia(®) Influenza A+B and the Sofia(®) RSV fluorescence immunoassays (FIAs), two novel rapid detection tests (RDTs) for influenza A and B and RSV. Two hundred and nine breath samples were selected from patients with respiratory symptoms determined to be positive/negative for influenza A, influenza B or RSV using one of the reference diagnostic techniques, cell culture and/or RT-PCR (Simplexa™Flu A/B & RSV). The Sofia Influenza A+B FIA was tested on 123 samples (63 from children and 60 from adults) and the Sofia RSV FIA was tested on 86 pediatric samples. Sensitivity and specificity values of both assays were calculated assuming the reference techniques as the gold standard. Sensitivity and specificity values for the Sofia Influenza A+B FIA were 73.1% and 97.8%, respectively. Sensitivity and specificity values for the Sofia RSV FIA were 87.5% and 86.7%, respectively. The sensitivity results obtained for the two assays were considerably higher than those reported for other RDTs. In conclusion, the Sofia Influenza A+B and the Sofia RSV FIAs are appropriate tools for the rapid diagnosis of these viruses. Copyright © 2015 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

[Sensing of Cu²⁺ Based on Fenton Reaction and Unmodified Gold Nanoparticles].

PubMed

Xing, Yun-peng; Liu, Chun; Zhou, Xiao-hong; Zhang, Li-pei; Shi, Han-chang

2015-11-01

Heavy metal pollution has received great attentions in recent years. The traditional methods for heavy metal detection rely on the expensive laboratory instruments and need time-consuming preparation steps; therefore, it is urgent to develop quick and highly sensitive new technologies for heavy metal detection. The colorimetric method based on the gold nanoparticles (AuNPs) features with simple operation, high sensitivity and low cost, therefore, enabling it widely concerned and used in the environmental monitoring, food safety and chemical and biological sensing fields. This work developed a simple, rapid and highly sensitive strategy based on the Fenton reaction and unmodified AuNPs for the detection of Cu²⁺ in water samples. The hydroxyl radical ( · OH) generated by the Fenton reaction between the Cu²⁺ and sodium ascorbate (SA) oxidized the single stranded DNA (ssDNA) attached on the AuNPs surface into variable sequence fragments. The cleavage of ssDNA induced the aggregation of AuNPs in a certain salt solution, therefore, resulting in the changes on the absorbance of solution. The assay conditions were optimized to be pH value of 7.9, 11 mg · L⁻¹ ssDNA, 8 mmol · L⁻¹ SA and 70 mmol · L⁻¹ NaCl. Results showed that the absorbance ratio values at the wavelengths of 700 and 525 nm (A₇₀₀/A₅₂₅) were linearly correlated with the Cu²⁺ concentrations. The linear detection range was 0.1-10.0 µmol · L⁻¹ with a detection limit of 24 nmol · L⁻¹ (3σ). Spiked recoveries ranged from 87%-120% in three sorts of water, including drinking water, tap water and lake water, which confirmed that the potentials of the proposed assay for Cu²⁺ detection in reality.

Evaluation of the Western blotting method for the diagnosis of congenital toxoplasmosis.

PubMed

Capobiango, Jaqueline Dario; Monica, Thaís Cabral; Ferreira, Fernanda Pinto; Mitsuka-Breganó, Regina; Navarro, Italmar Teodorico; Garcia, João Luis; Reiche, Edna Maria Vissoci

To evaluate the Western blotting method for the detection of IgG anti-Toxoplasma gondii (T. gondii) (IgG-WB) in the serum of children with suspected congenital toxoplasmosis. We accompanied 47 mothers with acquired toxoplasmosis in pregnancy and their children, between June of 2011 and June of 2014. The IgG-WB was done in house and the test was considered positive if the child had antibodies that recognized at least one band on IgG blots different from the mother's or with greater intensity than the corresponding maternal band, during the first three months of life. 15 children (15.1%) met the criteria for congenital toxoplasmosis and 32 (32.3%) had the diagnosis excluded. The symptoms were observed in 12 (80.0%) children and the most frequent were cerebral calcification in 9 (60.0%), chorioretinitis in 8 (53.3%), and hydrocephalus in 4 (26.6%). IgM antibodies anti-T. gondii detected by chemiluminescence (CL) were found in 6 (40.0%) children and the polymerase chain reaction (PCR) for detection of T. gondii DNA was positive in 5 of 7 performed (71.4%). The sensitivity of IgG-WB was of 60.0% [95% confidence interval (CI) 32.3-83.7%] and specificity 43.7% (95% CI 26.7-62.3%). The sensitivity of IgG-WB increased to 76.0 and 89.1% when associated to the research of IgM anti-T. gondii or PCR, respectively. The IgG-WB showed greater sensitivity than the detection of IgM anti-T. gondii; therefore, it can be used for the diagnosis of congenital toxoplasmosis in association with other congenital infection markers. Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

Heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(s)

NASA Technical Reports Server (NTRS)

Leu, Ming-Taun; Timonen, Raimo S.; Keyser, Leon F.; Yung, Yuk L.

1995-01-01

The heterogeneous reactions of HNO3(g) + NaCl(s) yields HCl(g) + NaNO3(s) (eq 1) and N2O5(g) + NaCl(s) yields ClNO2(g) + NaNO3(S) (eq 2) were investigated over the temperature range 223-296 K in a flow-tube reactor coupled to a quadrupole mass spectrometer. Either a chemical ionization mass spectrometer (CIMS) or an electron-impact ionization mass spectrometer (EIMS) was used to provide suitable detection sensitivity and selectivity. In order to mimic atmospheric conditions, partial pressures of HNO3 and N2O5 in the range 6 x 10(exp -8) - 2 x 10(exp -6) Torr were used. Granule sizes and surface roughness of the solid NaCl substrates were determined by using a scanning electron microscope. For dry NaCl substrates, decay rates of HNO3 were used to obtain gamma(1) = 0.013 +/- 0.004 (1sigma) at 296 K and > 0.008 at 223 K, respectively. The error quoted is the statistical error. After all corrections were made, the overall error, including systematic error, was estimated to be about a factor of 2. HCl was found to be the sole gas-phase product of reaction 1. The mechanism changed from heterogeneous reaction to predominantly physical adsorption when the reactor was cooled from 296 to 223 K. For reaction 2 using dry salts, gamma(2) was found to be less than 1.0 x 10(exp -4) at both 223 and 296 K. The gas-phase reaction product was identified as ClNO2 in previous studies using an infrared spectrometer. An enhancement in reaction probability was observed if water was not completely removed from salt surfaces, probably due to the reaction of N2O5(g) + H2O(s) yields 2HNO3(g). Our results are compared with previous literature values obtained using different experimental techniques and conditions. The implications of the present results for the enhancement of the hydrogen chloride column density in the lower stratosphere after the El Chichon volcanic eruption and for the chemistry of HCl and HNO3 in the marine troposphere are discussed.

X-ray detection capability of a BaCl{sub 2} single crystal scintillator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koshimizu, Masanori; CREST, Japan Science and Technology Agency, Sanbancho, Chiyoda-ku, Tokyo 102-0075; Onodera, Kazuya

2012-01-15

The x-ray detection capability of a scintillation detector equipped with a BaCl{sub 2} single crystal was evaluated. The scintillation decay kinetics can be expressed by a sum of two exponential decay components. The fast and slow components have lifetimes of 1.5 and 85 ns, respectively. The total light output is 5% that of YAP:Ce. A subnanosecond timing resolution was obtained. The detection efficiency of a 67.41 keV x-ray is 87% for a detector equipped with a BaCl{sub 2} crystal 6-mm thick. Thus, excellent timing resolution and high detection efficiency can be simultaneously achieved. Additionally, luminescence decay characteristics under vacuum ultravioletmore » excitation have been investigated. Radiative decay of self-trapped excitons is thought to be responsible for the fast scintillation component.« less

High concentrations of Na+ and Cl- ions in soil solution have simultaneous detrimental effects on growth of faba bean under salinity stress.

PubMed

Tavakkoli, Ehsan; Rengasamy, Pichu; McDonald, Glenn K

2010-10-01

Despite the fact that most plants accumulate both sodium (Na(+)) and chloride (Cl(-)) ions to high concentration in their shoot tissues when grown in saline soils, most research on salt tolerance in annual plants has focused on the toxic effects of Na(+) accumulation. There have also been some recent concerns about the ability of hydroponic systems to predict the responses of plants to salinity in soil. To address these two issues, an experiment was conducted to compare the responses to Na(+) and to Cl(-) separately in comparison with the response to NaCl in a soil-based system using two varieties of faba bean (Vicia faba), that differed in salinity tolerance. The variety Nura is a salt-sensitive variety that accumulates Na(+) and Cl(-) to high concentrations while the line 1487/7 is salt tolerant which accumulates lower concentrations of Na(+) and Cl(-). Soils were prepared which were treated with Na(+) or Cl(-) by using a combination of different Na(+) salts and Cl(-) salts, respectively, or with NaCl. While this method produced Na(+)-dominant and Cl(-)-dominant soils, it unavoidably led to changes in the availability of other anions and cations, but tissue analysis of the plants did not indicate any nutritional deficiencies or toxicities other than those targeted by the salt treatments. The growth, water use, ionic composition, photosynthesis, and chlorophyll fluorescence were measured. Both high Na(+) and high Cl(-) reduced growth of faba bean but plants were more sensitive to Cl(-) than to Na(+). The reductions in growth and photosynthesis were greater under NaCl stress and the effect was mainly additive. An important difference to previous hydroponic studies was that increasing the concentrations of NaCl in the soil increased the concentration of Cl(-) more than the concentration of Na(+). The data showed that salinity caused by high concentrations of NaCl can reduce growth by the accumulation of high concentrations of both Na(+) and Cl(-) simultaneously, but the effects of the two ions may differ. High Cl(-) concentration reduces the photosynthetic capacity and quantum yield due to chlorophyll degradation which may result from a structural impact of high Cl(-) concentration on PSII. High Na(+) interferes with K(+) and Ca(2+) nutrition and disturbs efficient stomatal regulation which results in a depression of photosynthesis and growth. These results suggest that the importance of Cl(-) toxicity as a cause of reductions in growth and yield under salinity stress may have been underestimated.

A competitive immunoassay for sensitive detection of small molecules chloramphenicol based on luminol functionalized silver nanoprobe.

PubMed

Yu, Xiuxia; He, Yi; Jiang, Jie; Cui, Hua

2014-02-17

Chloramphenicol (CHL) as a broad-spectrum antibiotic has a broad action spectrum against Gram-positive and Gram-negative bacteria, as well as anaerobes. The use of CHL is strictly restricted in poultry because of its toxic effect. However, CHL is still illegally used in animal farming because of its accessibility and low cost. Therefore, sensitive methods are highly desired for the determination of CHL in foodstuffs. The immunoassays based on labeling as an important tool have been reported for the detection of CHL residues in food-producing animals. However, most of the labeling procedures require multi-step reactions and purifications and thus they are complicated and time-consuming. Recently, in our previous work, luminol functionalized silver nanoparticles have been successfully synthesized, which exhibits higher CL efficiency than luminol functionalized gold nanoparticles. In this work, the new luminol functionalized silver nanoparticles have been used for the labeling of small molecules CHL for the first time and a competitive chemiluminescent immunoassay has been developed for the detection of CHL. Owing to the amplification of silver nanoparticles, high sensitivity for CHL could be achieved with a low detection limit of 7.6×10(-9) g mL(-1) and a wide linear dynamic range of 1.0×10(-8)-1.0×10(-6) g mL(-1). This method has also been successfully applied to determine CHL in milk and honey samples with a good recoveries (92% and 102%, 99% and 107% respectively), indicating that the method is feasible for the determination of CHL in real milk and honey samples. The labeling procedure is simple, convenient and fast, superior to previously reported labeling procedures. The immunoassay is also simple, fast, sensitive and selective. It is of application potential for the determination of CHL in foodstuffs. Copyright © 2014 Elsevier B.V. All rights reserved.

Acute spinal cord injury (SCI) transforms how GABA affects nociceptive sensitization.

PubMed

Huang, Yung-Jen; Lee, Kuan H; Murphy, Lauren; Garraway, Sandra M; Grau, James W

2016-11-01

Noxious input can sensitize pain (nociceptive) circuits within the spinal cord, inducing a lasting increase in spinal cord neural excitability (central sensitization) that is thought to contribute to chronic pain. The development of spinally-mediated central sensitization is regulated by descending fibers and GABAergic interneurons. The current study provides evidence that spinal cord injury (SCI) transforms how GABA affects nociceptive transmission within the spinal cord, recapitulating an earlier developmental state wherein GABA has an excitatory effect. In spinally transected rats, noxious electrical stimulation and inflammation induce enhanced mechanical reactivity (EMR), a behavioral index of nociceptive sensitization. Pretreatment with the GABA A receptor antagonist bicuculline blocked these effects. Peripheral application of an irritant (capsaicin) also induced EMR. Both the induction and maintenance of this effect were blocked by bicuculline. Cellular indices of central sensitization [c-fos expression and ERK phosphorylation (pERK)] were also attenuated. In intact (sham operated) rats, bicuculline had the opposite effect. Pretreatment with a GABA agonist (muscimol) attenuated nociceptive sensitization in intact, but not spinally injured, rats. The effect of SCI on GABA function was linked to a reduction in the Cl - transporter, KCC2, leading to a reduction in intracellular Cl - that would attenuate GABA-mediated inhibition. Pharmacologically blocking the KCC2 channel (with i.t. DIOA) in intact rats mimicked the effect of SCI. Conversely, a pharmacological treatment (bumetanide) that should increase intracellular Cl - levels blocked the effect of SCI. The results suggest that GABAergic neurons drive, rather than inhibit, the development of nociceptive sensitization after spinal injury. Copyright © 2016 Elsevier Inc. All rights reserved.

Determination of the hydrolysis rate constants and activation energy of aesculin with capillary electrophoresis end-column amperometric detection.

PubMed

Zhang, Lan; Tong, Ping; Chen, Guonan

2005-12-09

Aesculetin is the product of the hydrolysis reaction of aesculin. A high sensitivity and good repeatability method based on capillary electrophoresis with amperometric detection (CE-AD) was developed for simultaneous determination of aesculin and aesculetin in the hydrolysate of aesculin. Under the optimum condition: 10mmol/L KH(2)PO(4)-5mmol/L Na(2)B(4)O(7) (pH 6.0) buffer, separation at 18kV and +900mV (versus Ag/AgCl) as the detection potential, the hydrolysis rate constants of aesculin hydrolysis at 25, 30, 35, 40 and 45 degrees C in 0.1mol/L KOH were obtained as 1.45x10(-2)min(-1), 2.01x10(-2)min(-1), 2.93x10(-2)min(-1), 3.76x10(-2)min(-1) and 5.05x10(-2)min(-1), respectively. It was calculated that the activation energy for aesculin hydrolysis was 49.4kJ/mol.

Use of the thyrocyte sodium iodide symporter as the basis for a perchlorate cell-based assay.

PubMed

MacAllister, Irene E; Jakoby, Michael G; Geryk, Bruce; Schneider, Roger L; Cropek, Donald M

2009-02-01

Perchlorates are strong oxidants widely employed in military and civilian energetic materials and recently have been scrutinized as persistent environmental pollutants. The perchlorate anion, ClO(4)(-), is a well-known and potent competitive inhibitor of iodide transport by the sodium iodide symporter (NIS) expressed in the basolateral membranes of thyroid follicular cells (thyrocytes). Iodide uptake by thyroid follicular cells is rapid and reproducible. The competitive radiotransporter assay in this study shows promise as a rapid and convenient method to assay for ClO(4)(-) in water samples at the nM level. This work describes the initial efforts to define the assay conditions that enhance NIS selectivity for ClO(4)(-). Experiments of 10 min co-incubation of ClO(4)(-) and (125)I(-) demonstrate a more significant effect on (125)I(-) transport, with a quantifiable ClO(4)(-) concentration range of 50 nM (5 ppb) to 2 microM (200 ppb), and IC(50) of 180 nM (18 ppb), nearly three-fold lower than previous reports. Since the IC(50) in our assay for other known competitor anions (SCN(-), ClO(3)(-), NO(3)(-)) remains unchanged from previous research, the increased sensitivity for ClO(4)(-) also produces a three-fold enhancement in selectivity. In addition to the possible applicability of the thyrocyte to the development of a cellular perchlorate biosensor, we propose that the high affinity of the NIS for ClO(4)(-) also creates the potential for exploiting this membrane protein as a selective, sensitive, and broadly applicable biomechanical mechanism for controlled movement and concentration of perchlorate.

A simple method for the determination of glyphosate and aminomethylphosphonic acid in seawater matrix with high performance liquid chromatography and fluorescence detection.

PubMed

Wang, Shu; Liu, Baomin; Yuan, Dongxing; Ma, Jian

2016-12-01

Glyphosate (GLYP) is an important herbicide which is also used as the phosphorus source for marine organisms. The wide applications of GLYP can lead to its accumulation in oceans and coastal waters, thus creating environmental issues. However, there is limited methods for detection of GLYP and its degradation product, aminomethylphosphonic acid (AMPA) in saline samples. Therefore, a simple and fast method for the quantification of GLYP and AMPA in seawater matrix has been developed based on the derivatization with 9-fluorenylmethylchloroformate (FMOC-Cl), separation with high performance liquid chromatography (HPLC) and detection with fluorescence detector (FLD). In order to maximize sensitivity, the derivatization procedure was carefully optimized regarding concentration of FMOC-Cl, volume of borate buffer, pH of borate buffer, mixing and derivatization time. The derivatization reaction could be completed within 30min in seawater samples without any additional clean-up or desalting steps. Under the optimized conditions, the developed HPLC method showed a wide linear response (up to several mg/L, R 2 >0.99). The limits of detection were 0.60μg/L and 0.30μg/L for GLYP and AMPA in seawater matrix, respectively. The relative standard deviation was 14.0% for GLYP (1.00mg/L) and 3.1% for AMPA (100μg/L) in saline samples with three different operators (n=24). This method was applied to determine the concentration of GLYP and AMPA in seawater culture media and the recovery data indicated minimal matrix interference. Due to its simplicity, high reproducibility and successful application in seawater culture media analysis, this method is a potentially useful analytical technique for both marine research and environmental science. Copyright © 2016 Elsevier B.V. All rights reserved.

Proton-sensing transistor systems for detecting ion leakage from plasma membranes under chemical stimuli.

PubMed

Imaizumi, Yuki; Goda, Tatsuro; Schaffhauser, Daniel F; Okada, Jun-Ichi; Matsumoto, Akira; Miyahara, Yuji

2017-03-01

The membrane integrity of live cells is routinely evaluated for cytotoxicity induced by chemical or physical stimuli. Recent progress in bioengineering means that high-quality toxicity validation is required. Here, we report a pH-sensitive transistor system developed for the continuous monitoring of ion leakage from cell membranes upon challenge by toxic compounds. Temporal changes in pH were generated with high reproducibility via periodic flushing of HepG2 cells on a gate insulator of a proton-sensitive field-effect transistor with isotonic buffer solutions with/without NH 4 Cl. The pH transients at the point of NH 4 Cl addition/withdrawal originated from the free permeation of NH 3 across the semi-permeable plasma membranes, and the proton sponge effect produced by the ammonia equilibrium. Irreversible attenuation of the pH transient was observed when the cells were subjected to a membrane-toxic reagent. Experiments and simulations proved that the decrease in the pH transient was proportional to the area of the ion-permeable pores on the damaged plasma membranes. The pH signal was correlated with the degree of hemolysis produced by the model reagents. The pH assay was sensitive to the formation of molecularly sized pores that were otherwise not measurable via detection of the leakage of hemoglobin, because the hydrodynamic radius of hemoglobin was greater than 3.1nm in the hemolysis assay. The pH transient was not disturbed by inherent ion-transporter activity. The ISFET assay was applied to a wide variety of cell types. The system presented here is fast, sensitive, practical and scalable, and will be useful for validating cytotoxins and nanomaterials. The plasma membrane toxicity and hemolysis are widely and routinely evaluated in biomaterials science and biomedical engineering. Despite the recent development of a variety of methods/materials for efficient gene/drug delivery systems to the cytosol, the methodologies for safety validation remain unchanged in many years while leaving some major issues such as sensitivity, accuracy, and fast response. The paper describes a new way of measuring the plasma membrane leakage in real time upon challenge by toxic reagents using a solid-state transistor that is sensitive to proton as the smallest indicator. Our system was reliable and was correlated to the results from hemolysis assay with advanced features in sensitivity, fast response, and wide applicability to chemical species. The downsizing and integration features of semiconductor fabrication technologies may realize cytotoxicity assays at the single-cell level in multi-parallel. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Nucleic acid sensor for insecticide detection.

PubMed

Solanki, Pratima R; Prabhakar, Nirmal; Pandey, M K; Malhotra, B D

2008-01-01

Nucleic acid sensor based on polyaniline (PANI) has been fabricated by covalently immobilizing double stranded calf thymus (dsCT) DNA onto perchlorate (ClO(-) (4))-doped PANI film deposited onto indium-tin-oxide (ITO) glass plate using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS) chemistry. These dsCT-DNA-PANI-ClO(4)/ITO and PANI-ClO(4)/ITO electrodes have been characterized using square wave voltammetry, electrochemical impedance, scanning electron microscopy (SEM) and Fourier-transform-infrared (FTIR) measurements. This disposable dsCT-DNA-PANI-ClO(4)/ITO bioelectrode, stable for about 4 months, can be used to detect cypermethrin (0.005 ppm) and trichlorfon (0.01 ppm) in 30 and 60 s, respectively. John Wiley & Sons, Ltd

Monitoring of Legionella pneumophila viability after chlorine dioxide treatment using flow cytometry.

PubMed

Mustapha, Pascale; Epalle, Thibaut; Allegra, Séverine; Girardot, Françoise; Garraud, Olivier; Riffard, Serge

2015-04-01

The viability of three Legionella pneumophila strains was monitored after chlorine dioxide (ClO2) treatment using a flow cytometric assay. Suspensions of L. pneumophila cells were submitted to increasing concentrations of ClO2. Culturable cells were still detected when using 4 mg/L, but could no longer be detected after exposure to 6 mg/L of ClO2, although viable but not culturable (VBNC) cells were found after exposure to 4-5 mg/L of ClO2. When testing whether these VBNC were infective, two of the strains were resuscitated after co-culture with Acanthamoeba polyphaga, but neither of them could infect macrophage-like cells. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Synthesis of Polyfunctional Diorganomagnesium and Diorganozinc Reagents through In Situ Trapping Halogen-Lithium Exchange of Highly Functionalized (Hetero)aryl Halides in Continuous Flow.

PubMed

Ketels, Marthe; Ganiek, Maximilian A; Weidmann, Niels; Knochel, Paul

2017-10-02

We report a halogen-lithium exchange performed in the presence of various metal salts (ZnCl 2 , MgCl 2 ⋅LiCl) on a broad range of sensitive bromo- or iodo(hetero)arenes using BuLi or PhLi as the exchange reagent and a commercially available continuous-flow setup. The resulting diarylmagnesium or diarylzinc species were trapped with various electrophiles, resulting in the formation of polyfunctional (hetero)arenes in high yields. This method enables the functionalization of (hetero)arenes containing highly sensitive groups such as an isothiocyanate, nitro, azide, or ester. A straightforward scale-up was possible without further optimization. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Identification of 4CL Genes in Desert Poplars and Their Changes in Expression in Response to Salt Stress.

PubMed

Zhang, Cai-Hua; Ma, Tao; Luo, Wen-Chun; Xu, Jian-Mei; Liu, Jian-Quan; Wan, Dong-Shi

2015-09-18

4-Coumarate:CoA ligase (4CL) genes are critical for the biosynthesis of plant phenylpropanoids. Here we identified 20 4CL genes in the genomes of two desert poplars (Populus euphratica and P. pruinosa) and salt-sensitive congener (P. trichocarpa), but 12 in Salix suchowensis (Salix willow). Phylogenetic analyses clustered all Salicaceae 4CL genes into two clades, and one of them (corresponding to the 4CL-like clade from Arabidopsis) showed signals of adaptive evolution, with more genes retained in Populus than Salix and Arabidopsis. We also found that 4CL12 (in 4CL-like clade) showed positive selection along the two desert poplar lineages. Transcriptional profiling analyses indicated that the expression of 4CL2, 4CL11, and 4CL12 changed significantly in one or both desert poplars in response to salt stress compared to that of in P. trichocarpa. Our results suggest that the evolution of the 4CL genes may have contributed to the development of salt tolerance in the two desert poplars.

Application of chlorine-36 technique in determining the age of modern groundwater in the Al-Zulfi province, Saudi Arabia.

PubMed

Challan, Mohsen B

2016-06-01

The present study aims to estimate the residence time of groundwater based on bomb-produced (36)Cl. (36)Cl/Cl ratios in the water samples are determined by inductively coupled plasma mass spectrometry and liquid scintillation counting. (36)Cl/Cl ratios in the groundwater were estimated to be 1.0-2.0 × 10(-12). Estimates of residence time were obtained by comparing the measured bomb-derived (36)Cl concentrations in groundwater with the background reference. Dating based on a (36)Cl bomb pulse may be more reliable and sensitive for groundwater recharged before 1975, back as far as the mid-1950s. The above (36)Cl background concentration was deduced by determining the background-corrected Dye-3 ice core data from the frozen Arctic data, according to the estimated total (36)Cl resources. The residence time of 7.81 × 10(4) y is obtained from extrapolated groundwater flow velocity. (36)Cl concentration in groundwater does not reflect the input of bomb pulse (36)Cl, and it belongs to the era before 1950.

Chemiluminescence resonance energy transfer imaging on magnetic particles for single-nucleotide polymorphism detection based on ligation chain reaction.

PubMed

Bi, Sai; Zhang, Zhipeng; Dong, Ying; Wang, Zonghua

2015-03-15

A novel ligation chain reaction (LCR) methodology for single-nucleotide polymorphism (SNP) detection was developed based on luminol-H2O2-horseradish peroxidase (HRP)-mimicking DNAzyme-fluorescein chemiluminescence resonance energy transfer (CRET) imaging on magnetic particles. For LCR, four unique target-complement probes (X and X(⁎), YG and Y(⁎)) for the amplification of K-ras (G12C) were designed by modifying G-quadruplex sequence at 3'-end of YG and fluorescein at 5'-end of Y(⁎). After the LCR, the resulting products of XYG/X(⁎)Y(⁎) with biotin-labeled X(⁎) were captured onto streptavidin-coated magnetic particles (SA-MPs) via specific biotin-SA interaction, which stimulated the CRET reaction from hemin/G-quadruplex-catalyzed luminol-H2O2 CL system to fluorescein. By collecting signals by a cooled low-light CCD, a CRET imaging method was proposed for visual detection and quantitative analysis of SNP. As low as 0.86fM mutant DNA was detected by this assay, and positive mutation detection was achieved with a wild-type to mutant ratio of 10,000:1. This high sensitivity and specificity could be attributed to not only the exponential amplification and excellent discrimination of LCR but also the employment of SA-MPs. SA-MPs ensured the feasibility of the proposed strategy, which also simplified the operations through magnetic separation and separated the reaction and detection procedures to improve sensitivity. The proposed LCR-CRET imaging strategy extends the application of signal amplification techniques to SNP detection, providing a promising platform for effective and high-throughput genetic diagnosis. Copyright © 2014 Elsevier B.V. All rights reserved.

Polymer Vesicle Sensor for Visual and Sensitive Detection of SO2 in Water.

PubMed

Huang, Tong; Hou, Zhilin; Xu, Qingsong; Huang, Lei; Li, Chuanlong; Zhou, Yongfeng

2017-01-10

This study reports the first polymer vesicle sensor for the visual detection of SO 2 and its derivatives in water. A strong binding ability between tertiary alkanolamines and SO 2 has been used as the driving force for the detection by the graft of tertiary amine alcohol (TAA) groups onto an amphiphilic hyperbranched multiarm polymer, which can self-assemble into vesicles with enriched TAA groups on the surface. The polymer vesicles will undergo proton exchange with cresol red (CR) to produce CR-immobilized vesicles (CR@vesicles). Subsequently, through competitive binding with the TAA groups between CR and SO 2 or HSO 3 - , the CR@vesicles (purple) can quickly change into SO 2 @vesicles (colorless) with the release of protonated CR (yellow). Such a fast purple to yellow transition in the solution allows the visual detection of SO 2 or its derivatives in water by the naked eye. A visual test paper for SO 2 gas has also been demonstrated by the adsorption of CR@vesicles onto paper. Meanwhile, the detection limit of CR@vesicles for HSO 3 - is approximately 25 nM, which is improved by approximately 30 times when compared with that of small molecule-based sensors with a similar structure (0.83 μM). Such an enhanced detection sensitivity should be related to the enrichment of TAA groups as well as the CR in CR@vesicles. In addition, the CR@vesicle sensors also show selectivity and specificity for the detection of SO 2 or HSO 3 - among anions such as F - , Br - , Cl - , SO 4 2- , NO 2 - , C 2 O 4 2- , S 2 O 3 2- , SCN - , AcO - , SO 3 2- , S 2- , and HCO 3 - .

High creatinine clearance in critically ill patients with community-acquired acute infectious meningitis.

PubMed

Lautrette, Alexandre; Phan, Thuy-Nga; Ouchchane, Lemlih; Aithssain, Ali; Tixier, Vincent; Heng, Anne-Elisabeth; Souweine, Bertrand

2012-09-27

A high dose of anti-infective agents is recommended when treating infectious meningitis. High creatinine clearance (CrCl) may affect the pharmacokinetic / pharmacodynamic relationships of anti-infective drugs eliminated by the kidneys. We recorded the incidence of high CrCl in intensive care unit (ICU) patients admitted with meningitis and assessed the diagnostic accuracy of two common methods used to identify high CrCl. Observational study performed in consecutive patients admitted with community-acquired acute infectious meningitis (defined by >7 white blood cells/mm3 in cerebral spinal fluid) between January 2006 and December 2009 to one medical ICU. During the first 7 days following ICU admission, CrCl was measured from 24-hr urine samples (24-hr-UV/P creatinine) and estimated according to Cockcroft-Gault formula and the simplified Modification of Diet in Renal Disease (MDRD) equation. High CrCl was defined as CrCl >140 ml/min/1.73 m2 by 24-hr-UV/P creatinine. Diagnostic accuracy was performed with ROC curves analysis. Thirty two patients were included. High CrCl was present in 8 patients (25%) on ICU admission and in 15 patients (47%) during the first 7 ICU days for a median duration of 3 (1-4) days. For the Cockcroft-Gault formula, the best threshold to predict high CrCl was 101 ml/min/1.73 m2 (sensitivity: 0.96, specificity: 0.75, AUC = 0.90 ± 0.03) with a negative likelihood ratio of 0.06. For the simplified MDRD equation, the best threshold to predict high CrCl was 108 ml/min/1.73 m2 (sensitivity: 0.91, specificity: 0.80, AUC = 0.88 ± 0.03) with a negative likelihood ratio of 0.11. There was no difference between the estimated methods in the diagnostic accuracy of identifying high CrCl (p = 0.30). High CrCl is frequently observed in ICU patients admitted with community-acquired acute infectious meningitis. The estimated methods of CrCl could be used as a screening tool to identify high CrCl.