Rapid fluorometric determination of perfluorooctanoic acid by its quenching effect on the fluorescence of quantum dots

International Nuclear Information System (INIS)

Liu, Qi; Huang, Aizhen; Wang, Nan; Zheng, Guan; Zhu, Lihua

2015-01-01

Analysis of perfluorooctanoic acid (PFOA) usually requires a combination of high-performance liquid chromatography and mass spectrometry, which is expensive and time-consuming. In the present work, water-soluble CdS quantum dots (QDs) were employed to develop a simple and rapid fluorometric method for the determination of PFOA. Strongly fluorescent CdS QDs were prepared by using 3-mercaptopropionic acid (MPA) as a stabilizer. It was observed that PFOA strongly quenched the fluorescence emission of the MPA-CdS QDs because PFOA promotes the aggregation of MPA-CdS QDs through a fluorine–fluorine affinity interaction. Under optimum conditions, the fluorescence intensity of MPA-CdS QDs was observed to decrease linearly with an increase in the concentration of PFOA from 0.5 to 40 μmol L −1 , with a limit of detection of 0.3 μmol L −1 . This new method was successfully implemented for the analysis of PFOA-spiked textile samples, with recoveries ranging from 95% to 113%. - Highlights: • PFOA significantly quenched the fluorescence emission of quantum dots (QDs). • A rapid and simple fluorescence sensor was proposed for determining PFOA by QDs. • PFOA determination could be completed within approximately 10 min. • The developed method had a working range of 0.5 to 40 μmol L −1 and a detection limit of 0.3 μmol L −1

The roles of family B and D DNA polymerases in Thermococcus species 9°N Okazaki fragment maturation.

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Greenough, Lucia; Kelman, Zvi; Gardner, Andrew F

2015-05-15

During replication, Okazaki fragment maturation is a fundamental process that joins discontinuously synthesized DNA fragments into a contiguous lagging strand. Efficient maturation prevents repeat sequence expansions, small duplications, and generation of double-stranded DNA breaks. To address the components required for the process in Thermococcus, Okazaki fragment maturation was reconstituted in vitro using purified proteins from Thermococcus species 9°N or cell extracts. A dual color fluorescence assay was developed to monitor reaction substrates, intermediates, and products. DNA polymerase D (polD) was proposed to function as the replicative polymerase in Thermococcus replicating both the leading and the lagging strands. It is shown here, however, that it stops before the previous Okazaki fragments, failing to rapidly process them. Instead, Family B DNA polymerase (polB) was observed to rapidly fill the gaps left by polD and displaces the downstream Okazaki fragment to create a flap structure. This flap structure was cleaved by flap endonuclease 1 (Fen1) and the resultant nick was ligated by DNA ligase to form a mature lagging strand. The similarities to both bacterial and eukaryotic systems and evolutionary implications of archaeal Okazaki fragment maturation are discussed. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Rapid fluorescence detection of pathogenic bacteria using magnetic enrichment technique combined with magnetophoretic chromatography.

Science.gov (United States)

Che, Yulan; Xu, Yi; Wang, Renjie; Chen, Li

2017-08-01

A rapid and sensitive analytical method was developed to detect pathogenic bacteria which combined magnetic enrichment, fluorescence labeling with polyethylene glycol (PEG) magnetophoretic chromatography. As pathogenic bacteria usually exist in complex matrixes at low concentration, an efficient enrichment is essential for diagnosis. In order to capture series types of pathogenic bacteria in samples, amino-modified magnetic nanoparticles (Fe 3 O 4 @SiO 2 -NH 2 ) were prepared for efficient enrichment by the electrostatic interaction with pathogenic bacteria. It was shown that the capture efficiency reached up to 95.4% for Escherichia coli (E. coli). Furthermore, quantitative analysis of the bacteria was achieved by using acridine orange (AO) as a fluorescence probe for the captured E. coli due to its ability of staining series types of bacteria and rapid labeling. In order to remove the free magnetic nanoparticles and redundant fluorescent reagent, the labeled suspension was poured into a PEG separation column and was separated by applying an external magnetic field. The presence of 100 cfu mL -1 E. coli could be detected for semi-quantitative analysis by observing the separation column with the naked eye, and the concentration could be further evaluated by fluorescence detection. All the above processes were finished within 80 min. It was demonstrated that a good linear relationship existed between the fluorescence intensity and the concentration of E. coli ranging from 10 2 to 10 6  cfu mL -1 , with a detection limit of 100 cfu mL -1 when E. coli acted as target bacteria. The recovery rate of E. coli was 93.6∼102.0% in tap water and cooked meat samples, and the RSD was lower than 7% (n = 6); the result coincided with the conventional plate count method. Graphical abstract ᅟ.

Rapid fluorometric determination of perfluorooctanoic acid by its quenching effect on the fluorescence of quantum dots

Energy Technology Data Exchange (ETDEWEB)

Liu, Qi; Huang, Aizhen; Wang, Nan, E-mail: nwang@hust.edu.cn; Zheng, Guan; Zhu, Lihua

2015-05-15

Analysis of perfluorooctanoic acid (PFOA) usually requires a combination of high-performance liquid chromatography and mass spectrometry, which is expensive and time-consuming. In the present work, water-soluble CdS quantum dots (QDs) were employed to develop a simple and rapid fluorometric method for the determination of PFOA. Strongly fluorescent CdS QDs were prepared by using 3-mercaptopropionic acid (MPA) as a stabilizer. It was observed that PFOA strongly quenched the fluorescence emission of the MPA-CdS QDs because PFOA promotes the aggregation of MPA-CdS QDs through a fluorine–fluorine affinity interaction. Under optimum conditions, the fluorescence intensity of MPA-CdS QDs was observed to decrease linearly with an increase in the concentration of PFOA from 0.5 to 40 μmol L{sup −1}, with a limit of detection of 0.3 μmol L{sup −1}. This new method was successfully implemented for the analysis of PFOA-spiked textile samples, with recoveries ranging from 95% to 113%. - Highlights: • PFOA significantly quenched the fluorescence emission of quantum dots (QDs). • A rapid and simple fluorescence sensor was proposed for determining PFOA by QDs. • PFOA determination could be completed within approximately 10 min. • The developed method had a working range of 0.5 to 40 μmol L{sup −1} and a detection limit of 0.3 μmol L{sup −1}.

Rapid screening test for porphyria diagnosis using fluorescence spectroscopy

Science.gov (United States)

Lang, A.; Stepp, H.; Homann, C.; Hennig, G.; Brittenham, G. M.; Vogeser, M.

2015-07-01

Porphyrias are rare genetic metabolic disorders, which result from deficiencies of enzymes in the heme biosynthesis pathway. Depending on the enzyme defect, different types of porphyrins and heme precursors accumulate for the different porphyria diseases in erythrocytes, liver, blood plasma, urine and stool. Patients with acute hepatic porphyrias can suffer from acute neuropathic attacks, which can lead to death when undiagnosed, but show only unspecific clinical symptoms such as abdominal pain. Therefore, in addition to chromatographic methods, a rapid screening test is required to allow for immediate identification and treatment of these patients. In this study, fluorescence spectroscopic measurements were conducted on blood plasma and phantom material, mimicking the composition of blood plasma of porphyria patients. Hydrochloric acid was used to differentiate the occurring porphyrins (uroporphyrin-III and coproporphyrin-III) spectroscopically despite their initially overlapping excitation spectra. Plasma phantom mixtures were measured using dual wavelength excitation and the corresponding concentrations of uroporphyrin-III and coproporphyrin-III were determined. Additionally, three plasma samples of porphyria patients were examined and traces of coproporphyrin-III and uroporphyrin-III were identified. This study may therefore help to establish a rapid screening test method with spectroscopic differentiation of the occurring porphyrins, which consequently allows for the distinction of different porphyrias. This may be a valuable tool for clinical porphyria diagnosis and rapid or immediate treatment.

Assessment of variable fluorescence fluorometry as an approach for rapidly detecting living photoautotrophs in ballast water

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First, Matthew R.; Robbins-Wamsley, Stephanie H.; Riley, Scott C.; Drake, Lisa A.

2018-03-01

Variable fluorescence fluorometry, an analytical approach that estimates the fluorescence yield of chlorophyll a (F0, a proximal measure of algal concentration) and photochemical yield (FV/FM, an indicator of the physiological status of algae) was evaluated as a means to rapidly assess photoautotrophs. Specifically, it was used to gauge the efficacy of ballast water treatment designed to reduce the transport and delivery of potentially invasive organisms. A phytoflagellate, Tetraselmis spp. (10-12 μm) and mixed communities of ambient protists were examined in both laboratory experiments and large-scale field trials simulating 5-d hold times in mock ballast tanks. In laboratory incubations, ambient organisms held in the dark exhibited declining F0 and FV/FM measurements relative to organisms held under lighted conditions. In field experiments, increases and decreases in F0 and FV/FM over the tank hold time corresponded to those of microscope counts of organisms in two of three trials. In the third trial, concentrations of organisms ≥ 10 and protists) increased while F0 and FV/FM decreased. Rapid and sensitive, variable fluorescence fluorometry is appropriate for detecting changes in organism concentrations and physiological status in samples dominated by microalgae. Changes in the heterotrophic community, which may become more prevalent in light-limited ballast tanks, would not be detected via variable fluorescence fluorometry, however.

An Analysis of the Observed Low-level Structure of Rapidly Intensifying and Mature Hurricane Earl (2010)

Science.gov (United States)

2014-01-01

structure. J. Atmos. Sci. 49: 919–942. Marks FD, Black PG, Montgomery MT, Burpee RW. 2008. Structure of the eye and eyewall of hurricane Hugo (1989...structure of rapidly intensifying and mature hurricane Earl (2010) Michael T. Montgomery,a* Jun A. Zhangb and Roger K. Smithc aDepartment of Meteorology...Naval Postgraduate School, Monterey, CA, USA bNOAA Hurricane Research Division, Miami, FL, USA cMeteorological Institute, Ludwig Maximilians, University

Exciton-controlled fluorescence: application to hybridization-sensitive fluorescent DNA probe.

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Okamoto, Akimitsu; Ikeda, Shuji; Kubota, Takeshi; Yuki, Mizue; Yanagisawa, Hiroyuki

2009-01-01

A hybridization-sensitive fluorescent probe has been designed for nucleic acid detection, using the concept of fluorescence quenching caused by the intramolecular excitonic interaction of fluorescence dyes. We synthesized a doubly thiazole orange-labeled nucleotide showing high fluorescence intensity for a hybrid with the target nucleic acid and effective quenching for the single-stranded state. This exciton-controlled fluorescent probe was applied to living HeLa cells using microinjection to visualize intracellular mRNA localization. Immediately after injection of the probe into the cell, fluorescence was observed from the probe hybridizing with the target RNA. This fluorescence rapidly decreased upon addition of a competitor DNA. Multicoloring of this probe resulted in the simple simultaneous detection of plural target nucleic acid sequences. This probe realized a large, rapid, reversible change in fluorescence intensity in sensitive response to the amount of target nucleic acid, and facilitated spatiotemporal monitoring of the behavior of intracellular RNA.

A recombinant estrogen receptor fragment-based homogeneous fluorescent assay for rapid detection of estrogens.

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Wang, Dan; Xie, Jiangbi; Zhu, Xiaocui; Li, Jinqiu; Zhao, Dongqin; Zhao, Meiping

2014-05-15

In this work, we demonstrate a novel estrogenic receptor fragment-based homogeneous fluorescent assay which enables rapid and sensitive detection of 17β-estradiol (E2) and other highly potent estrogens. A modified human estrogenic receptor fragment (N-His × 6-hER270-595-C-Strep tag II) has been constructed that contains amino acids 270-595 of wild-type human estrogenic receptor α (hER270-595) and two specific tags (6 × His and Strep tag II) fused to the N and C terminus, respectively. The designed receptor protein fragment could be easily produced by prokaryotic expression with high yield and high purity. The obtained protein exhibits high binding affinity to E2 and the two tags greatly facilitate the application of the recombinant protein. Taking advantage of the unique spectroscopic properties of coumestrol (CS), a fluorescent phytoestrogen, a CS/hER270-595-based fluorescent assay has been developed which can sensitively respond to E2 within 1.0 min with a linear working range from 0.1 to 20 ng/mL and a limit of detection of 0.1 ng/mL. The assay was successfully applied for rapid detection of E2 in the culture medium of rat hippocampal neurons. The method also holds great potential for high-throughput monitoring the variation of estrogen levels in complex biological fluids, which is crucial for investigation of the molecular basis of various estrogen-involved processes. Copyright © 2013 Elsevier B.V. All rights reserved.

A method for the rapid generation of nonsequential light-response curves of chlorophyll fluorescence.

Science.gov (United States)

Serôdio, João; Ezequiel, João; Frommlet, Jörg; Laviale, Martin; Lavaud, Johann

2013-11-01

Light-response curves (LCs) of chlorophyll fluorescence are widely used in plant physiology. Most commonly, LCs are generated sequentially, exposing the same sample to a sequence of distinct actinic light intensities. These measurements are not independent, as the response to each new light level is affected by the light exposure history experienced during previous steps of the LC, an issue particularly relevant in the case of the popular rapid light curves. In this work, we demonstrate the proof of concept of a new method for the rapid generation of LCs from nonsequential, temporally independent fluorescence measurements. The method is based on the combined use of sample illumination with digitally controlled, spatially separated beams of actinic light and a fluorescence imaging system. It allows the generation of a whole LC, including a large number of actinic light steps and adequate replication, within the time required for a single measurement (and therefore named "single-pulse light curve"). This method is illustrated for the generation of LCs of photosystem II quantum yield, relative electron transport rate, and nonphotochemical quenching on intact plant leaves exhibiting distinct light responses. This approach makes it also possible to easily characterize the integrated dynamic light response of a sample by combining the measurement of LCs (actinic light intensity is varied while measuring time is fixed) with induction/relaxation kinetics (actinic light intensity is fixed and the response is followed over time), describing both how the response to light varies with time and how the response kinetics varies with light intensity.

Rapid Detection of Glycogen Synthase Kinase-3 Activity in Mouse Sperm Using Fluorescent Gel Shift Electrophoresis

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Hoseok Choi

2016-04-01

Full Text Available Assaying the glycogen synthase kinase-3 (GSK3 activity in sperm is of great importance because it is closely implicated in sperm motility and male infertility. While a number of studies on GSK3 activity have relied on labor-intensive immunoblotting to identify phosphorylated GSK3, here we report the simple and rapid detection of GSK3 activity in mouse sperm using conventional agarose gel electrophoresis and a fluorescent peptide substrate. When a dye-tethered and prephosphorylated (primed peptide substrate for GSK3 was employed, a distinct mobility shift in the fluorescent bands on the agarose was observed by GSK3-induced phosphorylation of the primed peptides. The GSK3 activity in mouse testes and sperm were quantifiable by gel shift assay with low sample consumption and were significantly correlated with the expression levels of GSK3 and p-GSK3. We suggest that our assay can be used for reliable and rapid detection of GSK3 activity in cells and tissue extracts.

Rapid Detection of Glycogen Synthase Kinase-3 Activity in Mouse Sperm Using Fluorescent Gel Shift Electrophoresis

Science.gov (United States)

Choi, Hoseok; Choi, Bomi; Seo, Ju Tae; Lee, Kyung Jin; Gye, Myung Chan; Kim, Young-Pil

2016-01-01

Assaying the glycogen synthase kinase-3 (GSK3) activity in sperm is of great importance because it is closely implicated in sperm motility and male infertility. While a number of studies on GSK3 activity have relied on labor-intensive immunoblotting to identify phosphorylated GSK3, here we report the simple and rapid detection of GSK3 activity in mouse sperm using conventional agarose gel electrophoresis and a fluorescent peptide substrate. When a dye-tethered and prephosphorylated (primed) peptide substrate for GSK3 was employed, a distinct mobility shift in the fluorescent bands on the agarose was observed by GSK3-induced phosphorylation of the primed peptides. The GSK3 activity in mouse testes and sperm were quantifiable by gel shift assay with low sample consumption and were significantly correlated with the expression levels of GSK3 and p-GSK3. We suggest that our assay can be used for reliable and rapid detection of GSK3 activity in cells and tissue extracts. PMID:27092510

Fluorescence-tracking of activation gating in human ERG channels reveals rapid S4 movement and slow pore opening.

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Zeineb Es-Salah-Lamoureux

2010-05-01

Full Text Available hERG channels are physiologically important ion channels which mediate cardiac repolarization as a result of their unusual gating properties. These are very slow activation compared with other mammalian voltage-gated potassium channels, and extremely rapid inactivation. The mechanism of slow activation is not well understood and is investigated here using fluorescence as a direct measure of S4 movement and pore opening.Tetramethylrhodamine-5-maleimide (TMRM fluorescence at E519 has been used to track S4 voltage sensor movement, and channel opening and closing in hERG channels. Endogenous cysteines (C445 and C449 in the S1-S2 linker bound TMRM, which caused a 10 mV hyperpolarization of the V((1/2 of activation to -27.5+/-2.0 mV, and showed voltage-dependent fluorescence signals. Substitution of S1-S2 linker cysteines with valines allowed unobstructed recording of S3-S4 linker E519C and L520C emission signals. Depolarization of E519C channels caused rapid initial fluorescence quenching, fit with a double Boltzmann relationship, F-V(ON, with V((1/2 (,1 = -37.8+/-1.7 mV, and V((1/2 (,2 = 43.5+/-7.9 mV. The first phase, V((1/2 (,1, was approximately 20 mV negative to the conductance-voltage relationship measured from ionic tail currents (G-V((1/2 = -18.3+/-1.2 mV, and relatively unchanged in a non-inactivating E519C:S620T mutant (V((1/2 = -34.4+/-1.5 mV, suggesting the fast initial fluorescence quenching tracked S4 voltage sensor movement. The second phase of rapid quenching was absent in the S620T mutant. The E519C fluorescence upon repolarization (V((1/2 = -20.6+/-1.2, k = 11.4 mV and L520C quenching during depolarization (V((1/2 = -26.8+/-1.0, k = 13.3 mV matched the respective voltage dependencies of hERG ionic tails, and deactivation time constants from -40 to -110 mV, suggesting they detected pore-S4 rearrangements related to ionic current flow during pore opening and closing.THE DATA INDICATE: 1 that rapid environmental changes occur at the

Rapid probing of photocatalytic activity on titania-based self-cleaning materials using 7-hydroxycoumarin fluorescent probe

International Nuclear Information System (INIS)

Guan Huimin; Zhu Lihua; Zhou Hehui; Tang Heqing

2008-01-01

Self-cleaning materials are widely applied, but the available methods for determining their photocatalytic activity are time consuming. A simple analysis method was proposed to evaluate rapidly the photocatalytic activity of self-cleaning materials. This method is based on monitoring of a highly fluorescent product generated by the self-cleaning materials after illumination. Under UV irradiation, holes photo-induced on the surface of self-cleaning materials can oxidize water molecules (or hydroxide ions) adsorbed on the surface to produce hydroxyl radicals, which then quantitatively oxidize coumarin to highly fluorescent 7-hydroxycoumarin. It was observed that the fluorescence intensity of photo-generated 7-hydroxycoumarin at 456 nm (excited at 346 nm) linearly increased with irradiation time, and the fluorescence intensity at a given irradiation time was linearly proportional to the photocatalytic activity of self-cleaning materials. Consequently, the photocatalytic activity of self-cleaning materials was able to be probed simply by using this new method, which requires an analysis time of 40 min, being much less than 250 min required for a dye method

Easy and Rapid Detection of Mumps Virus by Live Fluorescent Visualization of Virus-Infected Cells.

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Tadanobu Takahashi

Full Text Available Mumps viruses show diverse cytopathic effects (CPEs of infected cells and viral plaque formation (no CPE or no plaque formation in some cases depending on the viral strain, highlighting the difficulty in mumps laboratory studies. In our previous study, a new sialidase substrate, 2-(benzothiazol-2-yl-4-bromophenyl 5-acetamido-3,5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosidonic acid (BTP3-Neu5Ac, was developed for visualization of sialidase activity. BTP3-Neu5Ac can easily and rapidly perform histochemical fluorescent visualization of influenza viruses and virus-infected cells without an antiviral antibody and cell fixation. In the present study, the potential utility of BTP3-Neu5Ac for rapid detection of mumps virus was demonstrated. BTP3-Neu5Ac could visualize dot-blotted mumps virus, virus-infected cells, and plaques (plaques should be called focuses due to staining of infected cells in this study, even if a CPE was not observed. Furthermore, virus cultivation was possible by direct pick-up from a fluorescent focus. In conventional methods, visible appearance of the CPE and focuses often requires more than 6 days after infection, but the new method with BTP3-Neu5Ac clearly visualized infected cells after 2 days and focuses after 4 days. The BTP3-Neu5Ac assay is a precise, easy, and rapid assay for confirmation and titration of mumps virus.

A maturity model for blockchain adoption

OpenAIRE

Wang, Huaiqing; Chen, Kun; Xu, Dongming

2016-01-01

Background: The rapid development of the blockchain technology and its various applications has rendered it important to understand the guidelines for adopting it. Methods: The comparative analysis method is used to analyze different dimensions of the maturity model, which is mainly based on the commonly used capability maturity model. Results: The blockchain maturity model and its adoption process have been discussed and presented. Conclusions: This study serves as a guide to institutions to...

Fluorescent protein-tagged Vpr dissociates from HIV-1 core after viral fusion and rapidly enters the cell nucleus.

Science.gov (United States)

Desai, Tanay M; Marin, Mariana; Sood, Chetan; Shi, Jiong; Nawaz, Fatima; Aiken, Christopher; Melikyan, Gregory B

2015-10-29

HIV-1 Vpr is recruited into virions during assembly and appears to remain associated with the viral core after the reverse transcription and uncoating steps of entry. This feature has prompted the use of fluorescently labeled Vpr to visualize viral particles and to follow trafficking of post-fusion HIV-1 cores in the cytoplasm. Here, we tracked single pseudovirus entry and fusion and observed that fluorescently tagged Vpr gradually dissociates from post-fusion viral cores over the course of several minutes and accumulates in the nucleus. Kinetics measurements showed that fluorescent Vpr released from the cores very rapidly entered the cell nucleus. More than 10,000 Vpr molecules can be delivered into the cell nucleus within 45 min of infection by HIV-1 particles pseudotyped with the avian sarcoma and leukosis virus envelope glycoprotein. The fraction of Vpr from cell-bound viruses that accumulated in the nucleus was proportional to the extent of virus-cell fusion and was fully blocked by viral fusion inhibitors. Entry of virus-derived Vpr into the nucleus occurred independently of envelope glycoproteins or target cells. Fluorescence correlation spectroscopy revealed two forms of nuclear Vpr-monomers and very large complexes, likely involving host factors. The kinetics of viral Vpr entering the nucleus after fusion was not affected by point mutations in the capsid protein that alter the stability of the viral core. The independence of Vpr shedding of capsid stability and its relatively rapid dissociation from post-fusion cores suggest that this process may precede capsid uncoating, which appears to occur on a slower time scale. Our results thus demonstrate that a bulk of fluorescently labeled Vpr incorporated into HIV-1 particles is released shortly after fusion. Future studies will address the question whether the quick and efficient nuclear delivery of Vpr derived from incoming viruses can regulate subsequent steps of HIV-1 infection.

Fluorescent immunochromatography for rapid and sensitive typing of seasonal influenza viruses.

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Akira Sakurai

Full Text Available Lateral flow tests also known as Immunochromatography (IC is an antigen-detection method conducted on a nitrocellulose membrane that can be completed in less than 20 min. IC has been used as an important rapid test for clinical diagnosis and surveillance of influenza viruses, but the IC sensitivity is relatively low (approximately 60% and the limit of detection (LOD is as low as 10³ pfu per reaction. Recently, we reported an improved IC assay using antibodies conjugated with fluorescent beads (fluorescent immunochromatography; FLIC for subtyping H5 influenza viruses (FLIC-H5. Although the FLIC strip must be scanned using a fluorescent reader, the sensitivity (LOD is significantly improved over that of conventional IC methods. In addition, the antibodies which are specific against the subtypes of influenza viruses cannot be available for the detection of other subtypes when the major antigenicity will be changed. In this study, we established the use of FLIC to type seasonal influenza A and B viruses (FLIC-AB. This method has improved sensitivity to 100-fold higher than that of conventional IC methods when we used several strains of influenza viruses. In addition, FLIC-AB demonstrated the ability to detect influenza type A and influenza type B viruses from clinical samples with high sensitivity and specificity (Type A: sensitivity 98.7% (74/75, specificity 100% (54/54, Type B: sensitivity 100% (90/90, specificity 98.2% (54/55 in nasal swab samples in comparison to the results of qRT-PCR. And furthermore, FLIC-AB performs better in the detection of early stage infection (under 13 h than other conventional IC methods. Our results provide new strategies to prevent the early-stage transmission of influenza viruses in humans during both seasonal outbreaks and pandemics.

Rapid labeling of amino acid neurotransmitters with a fluorescent thiol in the presence of o-phthalaldehyde.

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Maddukuri, Naveen; Zhang, Qiyang; Zhang, Ning; Gong, Maojun

2017-02-01

LIF detection often requires labeling of analytes with fluorophores; and fast fluorescent derivatization is valuable for high-throughput analysis with flow-gated CE. Here, we report a fast fluorescein-labeling scheme for amino acid neurotransmitters, which were then rapidly separated and detected in flow-gated CE. This scheme was based on the reaction between primary amines and o-phthalaldehyde in the presence of a fluorescent thiol, 2-((5-fluoresceinyl)aminocarbonyl)ethyl mercaptan (FACE-SH). The short reaction time (neurotransmitters by coupling in vitro microdialysis with online derivatization and flow-gated CE. It is also anticipated that this fluorophore tagging scheme would be valuable for on-chip labeling of proteins retained on support in SPE. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a fluorescence-based sensor for rapid diagnosis of cyanide exposure.

Science.gov (United States)

Jackson, Randy; Oda, Robert P; Bhandari, Raj K; Mahon, Sari B; Brenner, Matthew; Rockwood, Gary A; Logue, Brian A

2014-02-04

Although commonly known as a highly toxic chemical, cyanide is also an essential reagent for many industrial processes in areas such as mining, electroplating, and synthetic fiber production. The "heavy" use of cyanide in these industries, along with its necessary transportation, increases the possibility of human exposure. Because the onset of cyanide toxicity is fast, a rapid, sensitive, and accurate method for the diagnosis of cyanide exposure is necessary. Therefore, a field sensor for the diagnosis of cyanide exposure was developed based on the reaction of naphthalene dialdehyde, taurine, and cyanide, yielding a fluorescent β-isoindole. An integrated cyanide capture "apparatus", consisting of sample and cyanide capture chambers, allowed rapid separation of cyanide from blood samples. Rabbit whole blood was added to the sample chamber, acidified, and the HCN gas evolved was actively transferred through a stainless steel channel to the capture chamber containing a basic solution of naphthalene dialdehyde (NDA) and taurine. The overall analysis time (including the addition of the sample) was cyanide exposure. Most importantly, the sensor was 100% accurate in diagnosing cyanide poisoning for acutely exposed rabbits.

Direct rapid analysis of trace bioavailable soil macronutrients by chemometrics-assisted energy dispersive X-ray fluorescence and scattering spectrometry

International Nuclear Information System (INIS)

Kaniu, M.I.; Angeyo, K.H.; Mwala, A.K.; Mangala, M.J.

2012-01-01

Highlights: ► Chemometrics-assisted EDXRFS spectroscopy realizes direct, rapid and accurate analysis of trace bioavailable macronutrients in soils. ► The method is minimally invasive, involves little sample preparation, short analysis times and is relatively insensitive to matrix effects. ► This opens up the ability to rapidly characterize large number of samples/matrices with this method. - Abstract: Precision agriculture depends on the knowledge and management of soil quality (SQ), which calls for affordable, simple and rapid but accurate analysis of bioavailable soil nutrients. Conventional SQ analysis methods are tedious and expensive. We demonstrate the utility of a new chemometrics-assisted energy dispersive X-ray fluorescence and scattering (EDXRFS) spectroscopy method we have developed for direct rapid analysis of trace ‘bioavailable’ macronutrients (i.e. C, N, Na, Mg, P) in soils. The method exploits, in addition to X-ray fluorescence, the scatter peaks detected from soil pellets to develop a model for SQ analysis. Spectra were acquired from soil samples held in a Teflon holder analyzed using 109 Cd isotope source EDXRF spectrometer for 200 s. Chemometric techniques namely principal component analysis (PCA), partial least squares (PLS) and artificial neural networks (ANNs) were utilized for pattern recognition based on fluorescence and Compton scatter peaks regions, and to develop multivariate quantitative calibration models based on Compton scatter peak respectively. SQ analyses were realized with high CMD (R 2 > 0.9) and low SEP (0.01% for N and Na, 0.05% for C, 0.08% for Mg and 1.98 μg g −1 for P). Comparison of predicted macronutrients with reference standards using a one-way ANOVA test showed no statistical difference at 95% confidence level. To the best of the authors’ knowledge, this is the first time that an XRF method has demonstrated utility in trace analysis of macronutrients in soil or related matrices.

Lead discovery for mammalian elongation of long chain fatty acids family 6 using a combination of high-throughput fluorescent-based assay and RapidFire mass spectrometry assay

International Nuclear Information System (INIS)

Takamiya, Mari; Sakurai, Masaaki; Teranishi, Fumie; Ikeda, Tomoko; Kamiyama, Tsutomu; Asai, Akira

2016-01-01

A high-throughput RapidFire mass spectrometry assay is described for elongation of very long-chain fatty acids family 6 (Elovl6). Elovl6 is a microsomal enzyme that regulates the elongation of C12-16 saturated and monounsaturated fatty acids. Elovl6 may be a new therapeutic target for fat metabolism disorders such as obesity, type 2 diabetes, and nonalcoholic steatohepatitis. To identify new Elovl6 inhibitors, we developed a high-throughput fluorescence screening assay in 1536-well format. However, a number of false positives caused by fluorescent interference have been identified. To pick up the real active compounds among the primary hits from the fluorescence assay, we developed a RapidFire mass spectrometry assay and a conventional radioisotope assay. These assays have the advantage of detecting the main products directly without using fluorescent-labeled substrates. As a result, 276 compounds (30%) of the primary hits (921 compounds) in a fluorescence ultra-high-throughput screening method were identified as common active compounds in these two assays. It is concluded that both methods are very effective to eliminate false positives. Compared with the radioisotope method using an expensive 14 C-labeled substrate, the RapidFire mass spectrometry method using unlabeled substrates is a high-accuracy, high-throughput method. In addition, some of the hit compounds selected from the screening inhibited cellular fatty acid elongation in HEK293 cells expressing Elovl6 transiently. This result suggests that these compounds may be promising lead candidates for therapeutic drugs. Ultra-high-throughput fluorescence screening followed by a RapidFire mass spectrometry assay was a suitable strategy for lead discovery against Elovl6. - Highlights: • A novel assay for elongation of very-long-chain fatty acids 6 (Elovl6) is proposed. • RapidFire mass spectrometry (RF-MS) assay is useful to select real screening hits. • RF-MS assay is proved to be beneficial because of

Bicarbonate Transport During Enamel Maturation.

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Yin, Kaifeng; Paine, Michael L

2017-11-01

Amelogenesis (tooth enamel formation) is a biomineralization process consisting primarily of two stages (secretory stage and maturation stage) with unique features. During the secretory stage, the inner epithelium of the enamel organ (i.e., the ameloblast cells) synthesizes and secretes enamel matrix proteins (EMPs) into the enamel space. The protein-rich enamel matrix forms a highly organized architecture in a pH-neutral microenvironment. As amelogenesis transitions to maturation stage, EMPs are degraded and internalized by ameloblasts through endosomal-lysosomal pathways. Enamel crystallite formation is initiated early in the secretory stage, however, during maturation stage the more rapid deposition of calcium and phosphate into the enamel space results in a rapid expansion of crystallite length and mineral volume. During maturation-stage amelogenesis, the pH value of enamel varies considerably from slightly above neutral to acidic. Extracellular acid-base balance during enamel maturation is tightly controlled by ameloblast-mediated regulatory networks, which include significant synthesis and movement of bicarbonate ions from both the enamel papillary layer cells and ameloblasts. In this review we summarize the carbonic anhydrases and the carbonate transporters/exchangers involved in pH regulation in maturation-stage amelogenesis. Proteins that have been shown to be instrumental in this process include CA2, CA6, CFTR, AE2, NBCe1, SLC26A1/SAT1, SLC26A3/DRA, SLC26A4/PDS, SLC26A6/PAT1, and SLC26A7/SUT2. In addition, we discuss the association of miRNA regulation with bicarbonate transport in tooth enamel formation.

Gas supply from WCSB -- Matured more rapidly than expected

International Nuclear Information System (INIS)

Hawkins, D. J.

2003-01-01

A 2002 National Energy Board report forecast a decline in short-term gas deliverability from the Western Canadian Sedimentary Basin (WCSB) through 2004. However, this report contradicts a 1999 report which forecast a robust supply of natural gas through 2010. To obtain some clarity about the situation, this article undertakes an assessment of the information on gas supply in Alberta during the second half of the 1990s, in an attempt to account for the dramatic shift in outlook for gas supply in the WCSB by 2002. After a thorough examination of natural gas activities in the Basin during the 1990s, the author concludes that gas production in the WCSB has matured more rapidly than expected; moreover, there were clear indications that this might occur as early as the mid-1990s. Further curtailment in Alberta gas production might be expected as the debate on gas production in the Athabasca area heats up. The result of the assessment is that new resources of gas such as coal-bed methane and natural gas deposits in northeast British Columbia may come on stream, but governments will be challenged to provide incentives for sustaining gas pipeline activity in the WCSB. In the longer term there is potential for a gas pipeline from Alaska, but there is still much uncertainty about the route, line size, operating pressure, utilization of downstream pipelines and ultimate timing. In Canada, there is considerable support for a gas pipeline in the Mackenzie Valley, and plans for development are well advanced. 9 refs., 7 figs

Synthesis of molecularly imprinted dye-silica nanocomposites with high selectivity and sensitivity: Fluorescent imprinted sensor for rapid and efficient detection of τ-fluvalinate in vodka.

Science.gov (United States)

Wang, Yunyun; Wang, Jixiang; Cheng, Rujia; Sun, Lin; Dai, Xiaohui; Yan, Yongsheng

2018-04-01

An imprinted fluorescent sensor was fabricated based on SiO 2 nanoparticles encapsulated with a molecularly imprinted polymer containing allyl fluorescein. High fluorine cypermethirin as template molecules, methyl methacrylate as functional monomer, and allyl fluorescein as optical materials synthesized a core-shell fluorescent molecular imprinted sensor, which showed a high and rapid sensitivity and selectivity for the detection of τ-fluvalinate. The sensor presented appreciable sensitivity with a limit of 13.251 nM, rapid detection that reached to equilibrium within 3 min, great linear relationship in the relevant concentration range from 0 to 150 nM, and excellent selectivity over structural analogues. In addition, the fluorescent sensor demonstrated desirable regeneration ability (eight cycling operations). The molecularly imprinted polymers ensured specificity, while the fluorescent dyes provided the stabile sensitivity. Finally, an effective application of the sensor was implemented by the detection of τ-fluvalinate in real samples from vodka. The molecularly imprinted fluorescent sensor showed a promising potential in environmental monitoring and food safety. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid genomic fingerprinting of Lactococcus lactis strains by arbitrarily primed polymerase chain reaction with 32P and fluorescent labels.

OpenAIRE

Cancilla, M R; Powell, I B; Hillier, A J; Davidson, B E

1992-01-01

Arbitrarily primed polymerase chain reaction, with incorporation of either radioactive or fluorescent labels, was used as a rapid and sensitive method for obtaining genomic fingerprints of strains of Lactococcus lactis. Closely related strains produced almost identical fingerprints. Fingerprints of other strains showed only some similarities.

Rectangular coordination polymer nanoplates: large-scale, rapid synthesis and their application as a fluorescent sensing platform for DNA detection.

Directory of Open Access Journals (Sweden)

Yingwei Zhang

Full Text Available In this paper, we report on the large-scale, rapid synthesis of uniform rectangular coordination polymer nanoplates (RCPNs assembled from Cu(II and 4,4'-bipyridine for the first time. We further demonstrate that such RCPNs can be used as a very effective fluorescent sensing platform for multiple DNA detection with a detection limit as low as 30 pM and a high selectivity down to single-base mismatch. The DNA detection is accomplished by the following two steps: (1 RCPN binds dye-labeled single-stranded DNA (ssDNA probe, which brings dye and RCPN into close proximity, leading to fluorescence quenching; (2 Specific hybridization of the probe with its target generates a double-stranded DNA (dsDNA which detaches from RCPN, leading to fluorescence recovery. It suggests that this sensing system can well discriminate complementary and mismatched DNA sequences. The exact mechanism of fluorescence quenching involved is elucidated experimentally and its use in a human blood serum system is also demonstrated successfully.

Rapid test for lung maturity, based on spectroscopy of gastric aspirate, predicted respiratory distress syndrome with high sensitivity

DEFF Research Database (Denmark)

Verder, Henrik; Heiring, Christian; Clark, Howard

2017-01-01

AIM: Respiratory distress syndrome (RDS) is a major cause of mortality and morbidity in premature infants. By the time symptoms appear, it may already be too late to prevent a severe course, with bronchopulmonary dysplasia or mortality. We aimed to develop a rapid test of lung maturity...... for targeting surfactant supplementation. METHODS: Concentrations of the most surface-active lung phospholipid dipalmitoylphosphatidylcholine and sphingomyelin in gastric aspirates from premature infants were measured by mass spectrometry and expressed as the lecithin/sphingomyelin ratio (L/S). The same...

TaqMan MGB probe fluorescence real-time quantitative PCR for rapid detection of Chinese Sacbrood virus.

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Ma Mingxiao

Full Text Available Sacbrood virus (SBV is a picorna-like virus that affects honey bees (Apis mellifera and results in the death of the larvae. Several procedures are available to detect Chinese SBV (CSBV in clinical samples, but not to estimate the level of CSBV infection. The aim of this study was develop an assay for rapid detection and quantification of this virus. Primers and probes were designed that were specific for CSBV structural protein genes. A TaqMan minor groove binder (MGB probe-based, fluorescence real-time quantitative PCR was established. The specificity, sensitivity and stability of the assay were assessed; specificity was high and there were no cross-reactivity with healthy larvae or other bee viruses. The assay was applied to detect CSBV in 37 clinical samples and its efficiency was compared with clinical diagnosis, electron microscopy observation, and conventional RT-PCR. The TaqMan MGB-based probe fluorescence real-time quantitative PCR for CSBV was more sensitive than other methods tested. This assay was a reliable, fast, and sensitive method that was used successfully to detect CSBV in clinical samples. The technology can provide a useful tool for rapid detection of CSBV. This study has established a useful protocol for CSBV testing, epidemiological investigation, and development of animal models.

Bead-based competitive fluorescence immunoassay for sensitive and rapid diagnosis of cyanotoxin risk in drinking water.

Science.gov (United States)

Yu, Hye-Weon; Jang, Am; Kim, Lan Hee; Kim, Sung-Jo; Kim, In S

2011-09-15

Due to the increased occurrence of cyanobacterial blooms and their toxins in drinking water sources, effective management based on a sensitive and rapid analytical method is in high demand for security of safe water sources and environmental human health. Here, a competitive fluorescence immunoassay of microcystin-LR (MCYST-LR) is developed in an attempt to improve the sensitivity, analysis time, and ease-of-manipulation of analysis. To serve this aim, a bead-based suspension assay was introduced based on two major sensing elements: an antibody-conjugated quantum dot (QD) detection probe and an antigen-immobilized magnetic bead (MB) competitor. The assay was composed of three steps: the competitive immunological reaction of QD detection probes against analytes and MB competitors, magnetic separation and washing, and the optical signal generation of QDs. The fluorescence intensity was found to be inversely proportional to the MCYST-LR concentration. Under optimized conditions, the proposed assay performed well for the identification and quantitative analysis of MCYST-LR (within 30 min in the range of 0.42-25 μg/L, with a limit of detection of 0.03 μg/L). It is thus expected that this enhanced assay can contribute both to the sensitive and rapid diagnosis of cyanotoxin risk in drinking water and effective management procedures.

Development of a Rapid Insulin Assay by Homogenous Time-Resolved Fluorescence.

Directory of Open Access Journals (Sweden)

Zachary J Farino

Full Text Available Direct measurement of insulin is critical for basic and clinical studies of insulin secretion. However, current methods are expensive and time-consuming. We developed an insulin assay based on homogenous time-resolved fluorescence that is significantly more rapid and cost-effective than current commonly used approaches. This assay was applied effectively to an insulin secreting cell line, INS-1E cells, as well as pancreatic islets, allowing us to validate the assay by elucidating mechanisms by which dopamine regulates insulin release. We found that dopamine functioned as a significant negative modulator of glucose-stimulated insulin secretion. Further, we showed that bromocriptine, a known dopamine D2/D3 receptor agonist and newly approved drug used for treatment of type II diabetes mellitus, also decreased glucose-stimulated insulin secretion in islets to levels comparable to those caused by dopamine treatment.

Genetically encoded ratiometric fluorescent thermometer with wide range and rapid response.

Directory of Open Access Journals (Sweden)

Masahiro Nakano

Full Text Available Temperature is a fundamental physical parameter that plays an important role in biological reactions and events. Although thermometers developed previously have been used to investigate several important phenomena, such as heterogeneous temperature distribution in a single living cell and heat generation in mitochondria, the development of a thermometer with a sensitivity over a wide temperature range and rapid response is still desired to quantify temperature change in not only homeotherms but also poikilotherms from the cellular level to in vivo. To overcome the weaknesses of the conventional thermometers, such as a limitation of applicable species and a low temporal resolution, owing to the narrow temperature range of sensitivity and the thermometry method, respectively, we developed a genetically encoded ratiometric fluorescent temperature indicator, gTEMP, by using two fluorescent proteins with different temperature sensitivities. Our thermometric method enabled a fast tracking of the temperature change with a time resolution of 50 ms. We used this method to observe the spatiotemporal temperature change between the cytoplasm and nucleus in cells, and quantified thermogenesis from the mitochondria matrix in a single living cell after stimulation with carbonyl cyanide 4-(trifluoromethoxyphenylhydrazone, which was an uncoupler of oxidative phosphorylation. Moreover, exploiting the wide temperature range of sensitivity from 5°C to 50°C of gTEMP, we monitored the temperature in a living medaka embryo for 15 hours and showed the feasibility of in vivo thermometry in various living species.

Rapid Chemometric X-Ray Fluorescence approaches for spectral Diagnostics of Cancer utilizing Tissue Trace Metals and Speciation profiles

International Nuclear Information System (INIS)

Okonda, J.J.

2015-01-01

Energy dispersive X-ray fluorescence (EDXRF) spectroscopy is an analytical method for identification and quantification of elements in materials by measurement of their spectral energy and intensity. EDXRFS spectroscopic technique involves simultaneous non-invasive acquisition of both fluorescence and scatter spectra from samples for quantitative determination of trace elemental content in complex matrix materials. The objective is develop a chemometric-aided EDXRFS method for rapid diagnosis of cancer and its severity (staging) based on analysis of trace elements (Cu, Zn, Fe, Se and Mn), their speciation and multivariate alterations of the elements in cancerous body tissue samples as cancer biomarkers. The quest for early diagnosis of cancer is based on the fact that early intervention translates to higher survival rate and better quality of life. Chemometric aided EDXRFS cancer diagnostic model has been evaluated as a direct and rapid superior alternative for the traditional quantitative methods used in XRF such as FP method. PCA results of cultured samples indicate that it is possible to characterize cancer at early and late stage of development based on trace elemental profiles

[Rapid Identification of Epicarpium Citri Grandis via Infrared Spectroscopy and Fluorescence Spectrum Imaging Technology Combined with Neural Network].

Science.gov (United States)

Pan, Sha-sha; Huang, Fu-rong; Xiao, Chi; Xian, Rui-yi; Ma, Zhi-guo

2015-10-01

To explore rapid reliable methods for detection of Epicarpium citri grandis (ECG), the experiment using Fourier Transform Attenuated Total Reflection Infrared Spectroscopy (FTIR/ATR) and Fluorescence Spectrum Imaging Technology combined with Multilayer Perceptron (MLP) Neural Network pattern recognition, for the identification of ECG, and the two methods are compared. Infrared spectra and fluorescence spectral images of 118 samples, 81 ECG and 37 other kinds of ECG, are collected. According to the differences in tspectrum, the spectra data in the 550-1 800 cm(-1) wavenumber range and 400-720 nm wavelength are regarded as the study objects of discriminant analysis. Then principal component analysis (PCA) is applied to reduce the dimension of spectroscopic data of ECG and MLP Neural Network is used in combination to classify them. During the experiment were compared the effects of different methods of data preprocessing on the model: multiplicative scatter correction (MSC), standard normal variable correction (SNV), first-order derivative(FD), second-order derivative(SD) and Savitzky-Golay (SG). The results showed that: after the infrared spectra data via the Savitzky-Golay (SG) pretreatment through the MLP Neural Network with the hidden layer function as sigmoid, we can get the best discrimination of ECG, the correct percent of training set and testing set are both 100%. Using fluorescence spectral imaging technology, corrected by the multiple scattering (MSC) results in the pretreatment is the most ideal. After data preprocessing, the three layers of the MLP Neural Network of the hidden layer function as sigmoid function can get 100% correct percent of training set and 96.7% correct percent of testing set. It was shown that the FTIR/ATR and fluorescent spectral imaging technology combined with MLP Neural Network can be used for the identification study of ECG and has the advantages of rapid, reliable effect.

Activation-Dependent Rapid Postsynaptic Clustering of Glycine Receptors in Mature Spinal Cord Neurons

Science.gov (United States)

Eto, Kei; Murakoshi, Hideji; Watanabe, Miho; Hirata, Hiromi; Moorhouse, Andrew J.; Ishibashi, Hitoshi

2017-01-01

Abstract Inhibitory synapses are established during development but continue to be generated and modulated in strength in the mature nervous system. In the spinal cord and brainstem, presynaptically released inhibitory neurotransmitter dominantly switches from GABA to glycine during normal development in vivo. While presynaptic mechanisms of the shift of inhibitory neurotransmission are well investigated, the contribution of postsynaptic neurotransmitter receptors to this shift is not fully elucidated. Synaptic clustering of glycine receptors (GlyRs) is regulated by activation-dependent depolarization in early development. However, GlyR activation induces hyperpolarization after the first postnatal week, and little is known whether and how presynaptically released glycine regulates postsynaptic receptors in a depolarization-independent manner in mature developmental stage. Here we developed spinal cord neuronal culture of rodents using chronic strychnine application to investigate whether initial activation of GlyRs in mature stage could change postsynaptic localization of GlyRs. Immunocytochemical analyses demonstrate that chronic blockade of GlyR activation until mature developmental stage resulted in smaller clusters of postsynaptic GlyRs that could be enlarged upon receptor activation for 1 h in the mature stage. Furthermore, live cell-imaging techniques show that GlyR activation decreases its lateral diffusion at synapses, and this phenomenon is dependent on PKC, but neither Ca2+ nor CaMKII activity. These results suggest that the GlyR activation can regulate receptor diffusion and cluster size at inhibitory synapses in mature stage, providing not only new insights into the postsynaptic mechanism of shifting inhibitory neurotransmission but also the inhibitory synaptic plasticity in mature nervous system. PMID:28197549

Direct rapid analysis of trace bioavailable soil macronutrients by chemometrics-assisted energy dispersive X-ray fluorescence and scattering spectrometry

Energy Technology Data Exchange (ETDEWEB)

Kaniu, M.I., E-mail: ikaniu@uonbi.ac.ke [Institute of Nuclear Science and Technology, University of Nairobi, P.O. Box 30197-00100 Nairobi (Kenya); Angeyo, K.H. [Department of Physics, University of Nairobi, P.O. Box 30197-00100 Nairobi (Kenya); Mwala, A.K. [Department of Land Resource Management and Agricultural Technology, University of Nairobi, P.O. Box 30197-00100 Nairobi (Kenya); Mangala, M.J. [Institute of Nuclear Science and Technology, University of Nairobi, P.O. Box 30197-00100 Nairobi (Kenya)

2012-06-04

Highlights: Black-Right-Pointing-Pointer Chemometrics-assisted EDXRFS spectroscopy realizes direct, rapid and accurate analysis of trace bioavailable macronutrients in soils. Black-Right-Pointing-Pointer The method is minimally invasive, involves little sample preparation, short analysis times and is relatively insensitive to matrix effects. Black-Right-Pointing-Pointer This opens up the ability to rapidly characterize large number of samples/matrices with this method. - Abstract: Precision agriculture depends on the knowledge and management of soil quality (SQ), which calls for affordable, simple and rapid but accurate analysis of bioavailable soil nutrients. Conventional SQ analysis methods are tedious and expensive. We demonstrate the utility of a new chemometrics-assisted energy dispersive X-ray fluorescence and scattering (EDXRFS) spectroscopy method we have developed for direct rapid analysis of trace 'bioavailable' macronutrients (i.e. C, N, Na, Mg, P) in soils. The method exploits, in addition to X-ray fluorescence, the scatter peaks detected from soil pellets to develop a model for SQ analysis. Spectra were acquired from soil samples held in a Teflon holder analyzed using {sup 109}Cd isotope source EDXRF spectrometer for 200 s. Chemometric techniques namely principal component analysis (PCA), partial least squares (PLS) and artificial neural networks (ANNs) were utilized for pattern recognition based on fluorescence and Compton scatter peaks regions, and to develop multivariate quantitative calibration models based on Compton scatter peak respectively. SQ analyses were realized with high CMD (R{sup 2} > 0.9) and low SEP (0.01% for N and Na, 0.05% for C, 0.08% for Mg and 1.98 {mu}g g{sup -1} for P). Comparison of predicted macronutrients with reference standards using a one-way ANOVA test showed no statistical difference at 95% confidence level. To the best of the authors' knowledge, this is the first time that an XRF method has demonstrated

Boronic acids for fluorescence imaging of carbohydrates.

Science.gov (United States)

Sun, Xiaolong; Zhai, Wenlei; Fossey, John S; James, Tony D

2016-02-28

"Fluorescence imaging" is a particularly exciting and rapidly developing area of research; the annual number of publications in the area has increased ten-fold over the last decade. The rapid increase of interest in fluorescence imaging will necessitate the development of an increasing number of molecular receptors and binding agents in order to meet the demand in this rapidly expanding area. Carbohydrate biomarkers are particularly important targets for fluorescence imaging given their pivotal role in numerous important biological events, including the development and progression of many diseases. Therefore, the development of new fluorescent receptors and binding agents for carbohydrates is and will be increasing in demand. This review highlights the development of fluorescence imaging agents based on boronic acids a particularly promising class of receptors given their strong and selective binding with carbohydrates in aqueous media.

Atomic-fluorescence spectrophotometry

International Nuclear Information System (INIS)

Bakhturova, N.F.; Yudelevich, I.G.

1975-01-01

Atomic-fluorescence spectrophotometry, a comparatively new method for the analysis of trace quantities, has developed rapidly in the past ten years. Theoretical and experimental studies by many workers have shown that atomic-fluorescence spectrophotometry (AFS) is capable of achieving a better limit than atomic absorption for a large number of elements. The present review examines briefly the principles of atomic-fluorescence spectrophotometry and the types of fluorescent transition. The excitation sources, flame and nonflame atomizers, used in AFS are described. The limits of detection achieved up to the present, using flame and nonflame methods of atomization are given

A Rapid Label-Free Fluorescent Aptasensor PicoGreen-Based Strategy for Aflatoxin B₁ Detection in Traditional Chinese Medicines.

Science.gov (United States)

Zhang, Cheng; Dou, Xiaowen; Zhang, Lei; Sun, Meifeng; Zhao, Ming; OuYang, Zhen; Kong, Dandan; Antonio, F Logrieco; Yang, Meihua

2018-02-28

Aflatoxin B₁ (AFB₁) is a very hazardous carcinogen, readily contaminating foodstuffs and traditional Chinese medicines (TCMs) that has inspired increasing health concerns due to dietary exposure. Colloidal nanocrystals have been proposed as optical labels for aptasensor assembly, but these typically require tedious multistep conjugation and suffer from unsatisfactory robustness when used for complex matrices. In the present study, we report a rapid and sensitive method for screening for trace AFB₁ levels in TCMs using a label-free fluorescent aptasensor PicoGreen dye-based strategy. Using PicoGreen to selectively measure complementary double-stranded DNA, fluorescence enhancement due to dsDNA is 'turned off' in the presence of AFB₁ due binding of aptamer target over complementary sequence. Self-assembly of a label-free fluorescent aptasensor based on AFB₁ aptamer and PicoGreen dye was performed. Due to competition between the complementary sequence and AFB₁ target, this rapid method was capable of highly sensitive and selective screening for AFB₁ in five types of TCMs. This proposed approach had a limit of detection as low as 0.1 μg·L -1 and good linearity with a range of 0.1-10 μg·L -1 (0.1-10 ppb). Among the 20 samples tested, 6 batches were found to be contaminated with AFB₁ using this method, which was confirmed using sophisticated liquid chromatography-electrospray ionization-tandem mass spectrometry/mass spectrometry analysis. The results of this study indicate the developed method has the potential to be a simple, quick, and sensitive tool for detecting AFB₁ in TCMs.

A rapid and cost-effective fluorescence detection in tube (FDIT) method to analyze protein phosphorylation.

Science.gov (United States)

Jin, Xiao; Gou, Jin-Ying

2016-01-01

Protein phosphorylation is one of the most important post-translational modifications catalyzed by protein kinases in living organisms. The advance of genome sequencing provided the information of protein kinase families in many organisms, including both model and non-model plants. The development of proteomics technologies also enabled scientists to efficiently reveal a large number of protein phosphorylations of an organism. However, kinases and phosphorylation targets are still to be connected to illustrate the complicated network in life. Here we adapted Pro-Q ® Diamond (Pro-Q ® Diamond Phosphoprotein Gel Stain), a widely used phosphoprotein gel-staining fluorescence dye, to establish a rapid, economical and non-radioactive fluorescence detection in tube (FDIT) method to analyze phosphorylated proteins. Taking advantages of high sensitivity and specificity of Pro-Q ® diamond, the FDIT method is also demonstrated to be rapid and reliable, with a suitable linear range for in vitro protein phosphorylation. A significant and satisfactory protein kinase reaction was detected as fast as 15 min from Wheat Kinase START 1.1 (WKS1.1) on a thylakoid ascorbate peroxidase (tAPX), an established phosphorylation target in our earlier study. The FDIT method saves up to 95% of the dye consumed in a gel staining method. The FDIT method is remarkably quick, highly reproducible, unambiguous and capable to be scaled up to dozens of samples. The FDIT method could serve as a simple and sensitive alternative procedure to determine protein kinase reactions with zero radiation exposure, as a supplementation to other widely used radioactive and in-gel assays.

A rapid and cost-effective fluorescence detection in tube (FDIT method to analyze protein phosphorylation

Directory of Open Access Journals (Sweden)

Xiao Jin

2016-11-01

Full Text Available Abstract Background Protein phosphorylation is one of the most important post-translational modifications catalyzed by protein kinases in living organisms. The advance of genome sequencing provided the information of protein kinase families in many organisms, including both model and non-model plants. The development of proteomics technologies also enabled scientists to efficiently reveal a large number of protein phosphorylations of an organism. However, kinases and phosphorylation targets are still to be connected to illustrate the complicated network in life. Results Here we adapted Pro-Q® Diamond (Pro-Q® Diamond Phosphoprotein Gel Stain, a widely used phosphoprotein gel-staining fluorescence dye, to establish a rapid, economical and non-radioactive fluorescence detection in tube (FDIT method to analyze phosphorylated proteins. Taking advantages of high sensitivity and specificity of Pro-Q® diamond, the FDIT method is also demonstrated to be rapid and reliable, with a suitable linear range for in vitro protein phosphorylation. A significant and satisfactory protein kinase reaction was detected as fast as 15 min from Wheat Kinase START 1.1 (WKS1.1 on a thylakoid ascorbate peroxidase (tAPX, an established phosphorylation target in our earlier study. Conclusion The FDIT method saves up to 95% of the dye consumed in a gel staining method. The FDIT method is remarkably quick, highly reproducible, unambiguous and capable to be scaled up to dozens of samples. The FDIT method could serve as a simple and sensitive alternative procedure to determine protein kinase reactions with zero radiation exposure, as a supplementation to other widely used radioactive and in-gel assays.

Dual-detection confocal fluorescence microscopy: fluorescence axial imaging without axial scanning.

Science.gov (United States)

Lee, Dong-Ryoung; Kim, Young-Duk; Gweon, Dae-Gab; Yoo, Hongki

2013-07-29

We propose a new method for high-speed, three-dimensional (3-D) fluorescence imaging, which we refer to as dual-detection confocal fluorescence microscopy (DDCFM). In contrast to conventional beam-scanning confocal fluorescence microscopy, where the focal spot must be scanned either optically or mechanically over a sample volume to reconstruct a 3-D image, DDCFM can obtain the depth of a fluorescent emitter without depth scanning. DDCFM comprises two photodetectors, each with a pinhole of different size, in the confocal detection system. Axial information on fluorescent emitters can be measured by the axial response curve through the ratio of intensity signals. DDCFM can rapidly acquire a 3-D fluorescent image from a single two-dimensional scan with less phototoxicity and photobleaching than confocal fluorescence microscopy because no mechanical depth scans are needed. We demonstrated the feasibility of the proposed method by phantom studies.

Fluorescent discharge lamp

Science.gov (United States)

Mukai, E.; Otsuka, H.; Nomi, K.; Honmo, I.

1982-01-01

A rapidly illuminating fluorescent lamp 1,200 mm long and 32.5 mm in diameter with an interior conducting strip which is compatible with conventional fixtures and ballasts is described. The fluorescent lamp is composed of a linear glass tube, electrodes sealed at both ends, mercury and raregas sealed in the glass tube, a fluorescent substance clad on the inner walls of the glass tube, and a clad conducting strip extending the entire length of the glass tube in the axial direction on the inner surface of the tube.

Direct rapid analysis of trace bioavailable soil macronutrients by chemometrics-assisted energy dispersive X-ray fluorescence and scattering spectrometry.

Science.gov (United States)

Kaniu, M I; Angeyo, K H; Mwala, A K; Mangala, M J

2012-06-04

Precision agriculture depends on the knowledge and management of soil quality (SQ), which calls for affordable, simple and rapid but accurate analysis of bioavailable soil nutrients. Conventional SQ analysis methods are tedious and expensive. We demonstrate the utility of a new chemometrics-assisted energy dispersive X-ray fluorescence and scattering (EDXRFS) spectroscopy method we have developed for direct rapid analysis of trace 'bioavailable' macronutrients (i.e. C, N, Na, Mg, P) in soils. The method exploits, in addition to X-ray fluorescence, the scatter peaks detected from soil pellets to develop a model for SQ analysis. Spectra were acquired from soil samples held in a Teflon holder analyzed using (109)Cd isotope source EDXRF spectrometer for 200 s. Chemometric techniques namely principal component analysis (PCA), partial least squares (PLS) and artificial neural networks (ANNs) were utilized for pattern recognition based on fluorescence and Compton scatter peaks regions, and to develop multivariate quantitative calibration models based on Compton scatter peak respectively. SQ analyses were realized with high CMD (R(2)>0.9) and low SEP (0.01% for N and Na, 0.05% for C, 0.08% for Mg and 1.98 μg g(-1) for P). Comparison of predicted macronutrients with reference standards using a one-way ANOVA test showed no statistical difference at 95% confidence level. To the best of the authors' knowledge, this is the first time that an XRF method has demonstrated utility in trace analysis of macronutrients in soil or related matrices. Copyright © 2012 Elsevier B.V. All rights reserved.

Fluorescent in situ folding control for rapid optimization of cell-free membrane protein synthesis.

Directory of Open Access Journals (Sweden)

Annika Müller-Lucks

Full Text Available Cell-free synthesis is an open and powerful tool for high-yield protein production in small reaction volumes predestined for high-throughput structural and functional analysis. Membrane proteins require addition of detergents for solubilization, liposomes, or nanodiscs. Hence, the number of parameters to be tested is significantly higher than with soluble proteins. Optimization is commonly done with respect to protein yield, yet without knowledge of the protein folding status. This approach contains a large inherent risk of ending up with non-functional protein. We show that fluorophore formation in C-terminal fusions with green fluorescent protein (GFP indicates the folding state of a membrane protein in situ, i.e. within the cell-free reaction mixture, as confirmed by circular dichroism (CD, proteoliposome reconstitution and functional assays. Quantification of protein yield and in-gel fluorescence intensity imply suitability of the method for membrane proteins of bacterial, protozoan, plant, and mammalian origin, representing vacuolar and plasma membrane localization, as well as intra- and extracellular positioning of the C-terminus. We conclude that GFP-fusions provide an extension to cell-free protein synthesis systems eliminating the need for experimental folding control and, thus, enabling rapid optimization towards membrane protein quality.

A Rapid, Onsite, Ultrasensitive Melamine Quantitation Method for Protein Beverages Using Time-Resolved Fluorescence Detection Paper.

Science.gov (United States)

Li, Guanghua; Wang, Du; Zhou, Aijun; Sun, Yimin; Zhang, Qi; Poapolathep, Amnart; Zhang, Li; Fan, Zhiyong; Zhang, Zhaowei; Li, Peiwu

2018-05-02

To ensure protein beverage safety and prevent illegal melamine use to artificially increase protein content, a rapid, onsite, ultrasensitive detection method for melamine must be developed because melamine is detrimental to human health and life. Herein, an ultrasensitive time-resolved fluorescence detection paper (TFDP) was developed to detect melamine in protein beverages within 15 min using a one-step sample preparation. The lower limits of detection were 0.89, 0.94, and 1.05 ng/mL, and the linear ranges were 2.67-150, 2.82-150, and 3.15-150 ng/mL (R2>0.982) for peanut, walnut, and coconut beverages, respectively. The recovery rates were 85.86-110.60% with a coefficient of variation beverage samples, the TFDP and ultra-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) results were consistent. This method is a promising alternative for rapid, onsite detection of melamine in beverages.

Rapid detection of toxic metals in non-crushed oyster shells by portable X-ray fluorescence spectrometry

Energy Technology Data Exchange (ETDEWEB)

Chou Ju, E-mail: Ju.Chou@selu.ed [Department of Chemistry and Physics, Southeastern Louisiana University, Hammond, LA 70402 (United States); Clement, Garret; Bursavich, Bradley; Elbers, Don [Department of Chemistry and Physics, Southeastern Louisiana University, Hammond, LA 70402 (United States); Cao Baobao; Zhou Weilie [Advanced Material Research Institute, University of New Orleans, New Orleans, LA 70148 (United States)

2010-06-15

The aim of this study was the multi-elemental detection of toxic metals such as lead (Pb) in non-crushed oyster shells by using a portable X-ray fluorescence (XRF) spectrometer. A rapid, simultaneous multi-element analytical methodology for non-crushed oyster shells has been developed using a portable XRF which provides a quick, quantitative, non-destructive, and cost-effective mean for assessment of oyster shell contamination from Pb. Pb contamination in oyster shells was further confirmed by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The results indicated that Pb is distributed in-homogeneously in contaminated shells. Oyster shells have a lamellar structure that could contribute to the high accumulation of Pb on oyster shells. - A rapid, simultaneous multi-element analytical methodology for non-crushed oyster shells has been developed using XRF and contamination of lead on oyster shells was confirmed by XRF and SEM-EDS.

Rapid detection of toxic metals in non-crushed oyster shells by portable X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Chou Ju; Clement, Garret; Bursavich, Bradley; Elbers, Don; Cao Baobao; Zhou Weilie

2010-01-01

The aim of this study was the multi-elemental detection of toxic metals such as lead (Pb) in non-crushed oyster shells by using a portable X-ray fluorescence (XRF) spectrometer. A rapid, simultaneous multi-element analytical methodology for non-crushed oyster shells has been developed using a portable XRF which provides a quick, quantitative, non-destructive, and cost-effective mean for assessment of oyster shell contamination from Pb. Pb contamination in oyster shells was further confirmed by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The results indicated that Pb is distributed in-homogeneously in contaminated shells. Oyster shells have a lamellar structure that could contribute to the high accumulation of Pb on oyster shells. - A rapid, simultaneous multi-element analytical methodology for non-crushed oyster shells has been developed using XRF and contamination of lead on oyster shells was confirmed by XRF and SEM-EDS.

Variations in fatty acid composition during maturation of cumin ...

African Journals Online (AJOL)

Changes in fatty acids were studied during maturation of cumin (Cuminum cyminum L.) seeds cultivated in the North-Eastern region of Tunisia (Menzel Temim). The fruits matured in 49 Days after flowering (DAF). The first results show a rapid oil accumulation started in newly formed fruits (8.2%) and continued until their full ...

Sensitive turn-on fluorescent detection of tartrazine based on fluorescence resonance energy transfer.

Science.gov (United States)

Huang, Sheng Tian; Shi, Yan; Li, Nian Bing; Luo, Hong Qun

2012-01-18

We introduce a sensitive, rapid, label-free and general fluorescent method for the determination of tartrazine by competitive binding to reduced graphene oxide (rGO) against fluorescein, and the fluorescence recovery upon fluorescein desorption from rGO provides a quantitative readout for tartrazine, giving a detection limit of 0.53 ng mL(-1).

Rapid determination of telmisartan in human plasma by HPLC using a monolithic column with fluorescence detection and its application to a bioequivalence study.

Science.gov (United States)

Zhang, He; Jiang, Yunyun; Wen, Jun; Zhou, Tingting; Fan, Guorong; Wu, Yutian

2009-11-01

A rapid HPLC method using a monolithic column with fluorescence detection has been developed for determination of telmisartan in human plasma. Sample preparation was done by protein precipitation with acetonitrile and naproxen was used as IS. The compounds were detected by fluorescence detection, using an excitation wavelength of 300 nm and emission wavelength of 385 nm. Calibration curves of telmisartan were linear in the range of 1-200 ng/mL. The assay was high throughput, sensitive and precise, and it was successfully applied to a bioequivalence study of two formulations of telmisartan.

Foxa2 and Pdx1 cooperatively regulate postnatal maturation of pancreatic β-cells

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Aimée Bastidas-Ponce

2017-06-01

Full Text Available Objective: The transcription factors (TF Foxa2 and Pdx1 are key regulators of beta-cell (β-cell development and function. Mutations of these TFs or their respective cis-regulatory consensus binding sites have been linked to maturity diabetes of the young (MODY, pancreas agenesis, or diabetes susceptibility in human. Although Foxa2 has been shown to directly regulate Pdx1 expression during mouse embryonic development, the impact of this gene regulatory interaction on postnatal β-cell maturation remains obscure. Methods: In order to easily monitor the expression domains of Foxa2 and Pdx1 and analyze their functional interconnection, we generated a novel double knock-in homozygous (FVFPBFDHom fluorescent reporter mouse model by crossing the previously described Foxa2-Venus fusion (FVF with the newly generated Pdx1-BFP (blue fluorescent protein fusion (PBF mice. Results: Although adult PBF homozygous animals exhibited a reduction in expression levels of Pdx1, they are normoglycemic. On the contrary, despite normal pancreas and endocrine development, the FVFPBFDHom reporter male animals developed hyperglycemia at weaning age and displayed a reduction in Pdx1 levels in islets, which coincided with alterations in β-cell number and islet architecture. The failure to establish mature β-cells resulted in loss of β-cell identity and trans-differentiation towards other endocrine cell fates. Further analysis suggested that Foxa2 and Pdx1 genetically and functionally cooperate to regulate maturation of adult β-cells. Conclusions: Our data show that the maturation of pancreatic β-cells requires the cooperative function of Foxa2 and Pdx1. Understanding the postnatal gene regulatory network of β-cell maturation will help to decipher pathomechanisms of diabetes and identify triggers to regenerate dedifferentiated β-cell mass. Keywords: Foxa2, Pdx1, β-Cell maturation, β-Cell identity, Trans-differentiation

Chlorophyll catabolism in olive fruits (var. Arbequina and Hojiblanca) during maturation.

Science.gov (United States)

Vergara-Domínguez, Honorio; Ríos, José Julían; Gandul-Rojas, Beatriz; Roca, María

2016-12-01

The central reaction of chlorophyll (chl) breakdown pathway occurring during olive fruits maturation is the cleavage of the macrocycle pheophorbide a to a primary fluorescent chl catabolite (pFCC) and it is catalyzed by two enzymes: pheophorbide a oxygenase (PaO) and red chl catabolite reductase (RCCR). In subsequent steps, pFCC is converted to different fluorescent chlorophyll catabolites (FCCs) and nonfluorescent chlorophyll catabolites (NCCs). This work demonstrated that RCCR activity of olive fruits is type II. During the study of evolution of PaO and RCCR activities through the olive fruits maturation in two varieties: Hojiblanca and Arbequina, a significant increase in PaO and RCCR activity was found in ripening stage. In addition, the profile and structure of NCCs present in epicarp of this fruit was studied using HPLC/ESI-TOF-MS. Five different NCCs were defined and for the first time the enzymatic reactions implied in chlorophyll degradations in olive fruits elucidated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fluorescent Biosensors Based on Single-Molecule Counting.

Science.gov (United States)

Ma, Fei; Li, Ying; Tang, Bo; Zhang, Chun-Yang

2016-09-20

Biosensors for highly sensitive, selective, and rapid quantification of specific biomolecules make great contributions to biomedical research, especially molecular diagnostics. However, conventional methods for biomolecular assays often suffer from insufficient sensitivity and poor specificity. In some case (e.g., early disease diagnostics), the concentration of target biomolecules is too low to be detected by these routine approaches, and cumbersome procedures are needed to improve the detection sensitivity. Therefore, there is an urgent need for rapid and ultrasensitive analytical tools. In this respect, single-molecule fluorescence approaches may well satisfy the requirement and hold promising potential for the development of ultrasensitive biosensors. Encouragingly, owing to the advances in single-molecule microscopy and spectroscopy over past decades, the detection of single fluorescent molecule comes true, greatly boosting the development of highly sensitive biosensors. By in vitro/in vivo labeling of target biomolecules with proper fluorescent tags, the quantification of certain biomolecule at the single-molecule level is achieved. In comparison with conventional ensemble measurements, single-molecule detection-based analytical methods possess the advantages of ultrahigh sensitivity, good selectivity, rapid analysis time, and low sample consumption. Consequently, single-molecule detection may be potentially employed as an ideal analytical approach to quantify low-abundant biomolecules with rapidity and simplicity. In this Account, we will summarize our efforts for developing a series of ultrasensitive biosensors based on single-molecule counting. Single-molecule counting is a member of single-molecule detection technologies and may be used as a very simple and ultrasensitive method to quantify target molecules by simply counting the individual fluorescent bursts. In the fluorescent sensors, the signals of target biomolecules may be translated to the

Mapping metals in Parkinson's and normal brain using rapid-scanning x-ray fluorescence

International Nuclear Information System (INIS)

Popescu, Bogdan F Gh; George, Martin J; McCrea, Richard P E; Devon, Richard M; George, Graham N; Hanson, Akela D; Chapman, L Dean; Nichol, Helen; Bergmann, Uwe; Garachtchenko, Alex V; Luening, Katharina; Kelly, Michael E; Harder, Sheri M; Pickering, Ingrid J

2009-01-01

Rapid-scanning x-ray fluorescence (RS-XRF) is a synchrotron technology that maps multiple metals in tissues by employing unique hardware and software to increase scanning speed. RS-XRF was validated by mapping and quantifying iron, zinc and copper in brain slices from Parkinson's disease (PD) and unaffected subjects. Regions and structures in the brain were readily identified by their metal complement and each metal had a unique distribution. Many zinc-rich brain regions were low in iron and vice versa. The location and amount of iron in brain regions known to be affected in PD agreed with analyses using other methods. Sample preparation is simple and standard formalin-fixed autopsy slices are suitable. RS-XRF can simultaneously and non-destructively map and quantify multiple metals and holds great promise to reveal metal pathologies associated with PD and other neurodegenerative diseases as well as diseases of metal metabolism.

[Rapid identification of hogwash oil by using synchronous fluorescence spectroscopy].

Science.gov (United States)

Sun, Yan-Hui; An, Hai-Yang; Jia, Xiao-Li; Wang, Juan

2012-10-01

To identify hogwash oil quickly, the characteristic delta lambda of hogwash oil was analyzed by three dimensional fluorescence spectroscopy with parallel factor analysis, and the model was built up by using synchronous fluorescence spectroscopy with support vector machines (SVM). The results showed that the characteristic delta lambda of hogwash oil was 60 nm. Collecting original spectrum of different samples under the condition of characteristic delta lambda 60 nm, the best model was established while 5 principal components were selected from original spectrum and the radial basis function (RBF) was used as the kernel function, and the optimal penalty factor C and kernel function g were 512 and 0.5 respectively obtained by the grid searching and 6-fold cross validation. The discrimination rate of the model was 100% for both training sets and prediction sets. Thus, it is quick and accurate to apply synchronous fluorescence spectroscopy to identification of hogwash oil.

DRAQ5 and Eosin ('D&E') as an Analog to Hematoxylin and Eosin for Rapid Fluorescence Histology of Fresh Tissues.

Science.gov (United States)

Elfer, Katherine N; Sholl, Andrew B; Wang, Mei; Tulman, David B; Mandava, Sree H; Lee, Benjamin R; Brown, J Quincy

2016-01-01

Real-time on-site histopathology review of biopsy tissues at the point-of-procedure has great potential for significant clinical value and improved patient care. For instance, on-site review can aid in rapid screening of diagnostic biopsies to reduce false-negative results, or in quantitative assessment of biospecimen quality to increase the efficacy of downstream laboratory and histopathology analysis. However, the only currently available rapid pathology method, frozen section analysis (FSA), is too time- and labor-intensive for use in screening large quantities of biopsy tissues and is too destructive for maximum tissue conservation in multiple small needle core biopsies. In this work we demonstrate the spectrally-compatible combination of the nuclear stain DRAQ5 and the anionic counterstain eosin as a dual-component fluorescent staining analog to hematoxylin and eosin intended for use on fresh, unsectioned tissues. Combined with optical sectioning fluorescence microscopy and pseudo-coloring algorithms, DRAQ5 and eosin ("D&E") enables very fast, non-destructive psuedohistological imaging of tissues at the point-of-acquisition with minimal tissue handling and processing. D&E was validated against H&E on a one-to-one basis on formalin-fixed paraffin-embedded and frozen section tissues of various human organs using standard epi-fluorescence microscopy, demonstrating high fidelity of the staining mechanism as an H&E analog. The method was then applied to fresh, whole 18G renal needle core biopsies and large needle core prostate biospecimen biopsies using fluorescence structured illumination optical sectioning microscopy. We demonstrate the ability to obtain high-resolution histology-like images of unsectioned, fresh tissues similar to subsequent H&E staining of the tissue. The application of D&E does not interfere with subsequent standard-of-care H&E staining and imaging, preserving the integrity of the tissue for thorough downstream analysis. These results indicate

DRAQ5 and Eosin ('D&E' as an Analog to Hematoxylin and Eosin for Rapid Fluorescence Histology of Fresh Tissues.

Directory of Open Access Journals (Sweden)

Katherine N Elfer

Full Text Available Real-time on-site histopathology review of biopsy tissues at the point-of-procedure has great potential for significant clinical value and improved patient care. For instance, on-site review can aid in rapid screening of diagnostic biopsies to reduce false-negative results, or in quantitative assessment of biospecimen quality to increase the efficacy of downstream laboratory and histopathology analysis. However, the only currently available rapid pathology method, frozen section analysis (FSA, is too time- and labor-intensive for use in screening large quantities of biopsy tissues and is too destructive for maximum tissue conservation in multiple small needle core biopsies. In this work we demonstrate the spectrally-compatible combination of the nuclear stain DRAQ5 and the anionic counterstain eosin as a dual-component fluorescent staining analog to hematoxylin and eosin intended for use on fresh, unsectioned tissues. Combined with optical sectioning fluorescence microscopy and pseudo-coloring algorithms, DRAQ5 and eosin ("D&E" enables very fast, non-destructive psuedohistological imaging of tissues at the point-of-acquisition with minimal tissue handling and processing. D&E was validated against H&E on a one-to-one basis on formalin-fixed paraffin-embedded and frozen section tissues of various human organs using standard epi-fluorescence microscopy, demonstrating high fidelity of the staining mechanism as an H&E analog. The method was then applied to fresh, whole 18G renal needle core biopsies and large needle core prostate biospecimen biopsies using fluorescence structured illumination optical sectioning microscopy. We demonstrate the ability to obtain high-resolution histology-like images of unsectioned, fresh tissues similar to subsequent H&E staining of the tissue. The application of D&E does not interfere with subsequent standard-of-care H&E staining and imaging, preserving the integrity of the tissue for thorough downstream analysis

Rapid maturation of the muscle biochemistry that supports diving in Pacific walruses (Odobenus rosmarus divergens)

Science.gov (United States)

Norem, Shawn R.; Jay, Chadwick V.; Burns, Jennifer M.; Fischbach, Anthony S.

2015-01-01

Physiological constraints dictate animals’ ability to exploit habitats. For marine mammals, it is important to quantify physiological limits that influence diving and their ability to alter foraging behaviors. We characterized age-specific dive limits of walruses by measuring anaerobic (acid-buffering capacity) and aerobic (myoglobin content) capacities of the muscles that power hind (longissimus dorsi) and fore (supraspinatus) flipper propulsion. Mean buffering capacities were similar across muscles and age classes (a fetus, five neonatal calves, a 3 month old and 20 adults), ranging from 41.31 to 54.14 slykes and 42.00 to 46.93 slykes in the longissimus and supraspinatus, respectively. Mean myoglobin in the fetus and neonatal calves fell within a narrow range (longissimus: 0.92–1.68 g 100 g−1 wet muscle mass; supraspinatus: 0.88–1.64 g 100 g−1 wet muscle mass). By 3 months post-partum, myoglobin in the longissimus increased by 79%, but levels in the supraspinatus remained unaltered. From 3 months post-partum to adulthood, myoglobin increased by an additional 26% in the longissimus and increased by 126% in the supraspinatus; myoglobin remained greater in the longissimus compared with the supraspinatus. Walruses are unique among marine mammals because they are born with a mature muscle acid-buffering capacity and attain mature myoglobin content early in life. Despite rapid physiological development, small body size limits the diving capacity of immature walruses and extreme sexual dimorphism reduces the diving capacity of adult females compared with adult males. Thus, free-ranging immature walruses likely exhibit the shortest foraging dives while adult males are capable of the longest foraging dives.

A highly selective and sensitive fluorescent chemosensor and its application for rapid on-site detection of Al3 +

Science.gov (United States)

Yue, Xiao-li; Wang, Zhao-qing; Li, Chao-rui; Yang, Zheng-yin

2018-03-01

In this paper, a simple naphthalene-based derivative (HL) has been designed and synthesized as a Al3 +-selective fluorescent chemosensor based on the PET mechanism. HL exhibited high selectivity and sensitivity towards Al3 + over other commonly coexisting metal ions in ethanol with a detection limit of 2.72 nM. The 1:1 binding stoichiometry of the complex (HL-Al3 +) was determined from the Job's plot based on fluorescence titrations and the ESI-MS spectrum data. Moreover, the binding site of HL with Al3 + was assured by the 1H NMR titration experiment. The binding constant (Ka) of the complex (HL-Al3 +) was calculated to be 5.06 × 104 M- 1 according to the Benesi-Hildebrand equation. In addition, the recognizing process of HL towards Al3 + was chemically reversible by adding Na2EDTA. Importantly, HL could directly and rapidly detect aluminum ion through the filter paper without resorting to additional instrumental analysis.

Geotechnical field investigation of the rapid densification phenomenon in oil sands mature fine tailings

Energy Technology Data Exchange (ETDEWEB)

Guo, C.; Chalaturnyk, R.J.; Scott, J.D.; Cyre, G. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering; MacKinnon, M. [Syncrude Canada Ltd., Edmonton, AB (Canada). Edmonton Research Centre

2002-07-01

The Mildred Lake Settling Basin (MLSB) is an oil sand tailings pond with a water area of about 11 square km and a maximum depth of mature fine tailings (MFT) of about 50 m, rendering it Syncrude's largest disposal site for tailings. Syncrude began storing the MFT in 1978 but in recent years there has been a sharp increase in the consolidation of the fine tailings, creating pumping challenges in the transfer of tailings from the MLSB for the creation of composite tailings. This paper presents preliminary results of field and laboratory study which have been launched to better manage the rapid densification of fine tailings. The study involves sampling, field vane tests, cone penetration tests, steel plate penetration tests and earth pressure measurements. Methane producing microorganisms have become very active in the part of the pond that is experiencing rapid densification. The objective of the study was to determine the inventory and distribution of high strength MFT in current storage ponds and to assess whether geotechnical properties are enough to support direct loading with solids such as sand, clay or coke. The cause of the phenomena was also examined along with ways to possibly enhance MFT development through microbial, physical or chemical treatments. Results show that the accumulation of methane gas may have reached a critical state in some parts of the pond. The densification phenomenon at the southern pond is more significant compared to the northern pond. Earth pressure measurements indicate that the earth pressure cell has good sensitivity and that the coefficient of earth pressure at rest is approximately one. Good agreement was reached between different testing methods used to determine geotechnical properties of MFT. 5 refs., 4 tabs., 14 figs.

Improved Savitzky-Golay-method-based fluorescence subtraction algorithm for rapid recovery of Raman spectra.

Science.gov (United States)

Chen, Kun; Zhang, Hongyuan; Wei, Haoyun; Li, Yan

2014-08-20

In this paper, we propose an improved subtraction algorithm for rapid recovery of Raman spectra that can substantially reduce the computation time. This algorithm is based on an improved Savitzky-Golay (SG) iterative smoothing method, which involves two key novel approaches: (a) the use of the Gauss-Seidel method and (b) the introduction of a relaxation factor into the iterative procedure. By applying a novel successive relaxation (SG-SR) iterative method to the relaxation factor, additional improvement in the convergence speed over the standard Savitzky-Golay procedure is realized. The proposed improved algorithm (the RIA-SG-SR algorithm), which uses SG-SR-based iteration instead of Savitzky-Golay iteration, has been optimized and validated with a mathematically simulated Raman spectrum, as well as experimentally measured Raman spectra from non-biological and biological samples. The method results in a significant reduction in computing cost while yielding consistent rejection of fluorescence and noise for spectra with low signal-to-fluorescence ratios and varied baselines. In the simulation, RIA-SG-SR achieved 1 order of magnitude improvement in iteration number and 2 orders of magnitude improvement in computation time compared with the range-independent background-subtraction algorithm (RIA). Furthermore the computation time of the experimentally measured raw Raman spectrum processing from skin tissue decreased from 6.72 to 0.094 s. In general, the processing of the SG-SR method can be conducted within dozens of milliseconds, which can provide a real-time procedure in practical situations.

Rapid isolation of antibody from a synthetic human antibody library by repeated fluorescence-activated cell sorting (FACS.

Directory of Open Access Journals (Sweden)

Sung Sun Yim

Full Text Available Antibodies and their derivatives are the most important agents in therapeutics and diagnostics. Even after the significant progress in the technology for antibody screening from huge libraries, it takes a long time to isolate an antibody, which prevents a prompt action against the spread of a disease. Here, we report a new strategy for isolating desired antibodies from a combinatorial library in one day by repeated fluorescence-activated cell sorting (FACS. First, we constructed a library of synthetic human antibody in which single-chain variable fragment (scFv was expressed in the periplasm of Escherichia coli. After labeling the cells with fluorescent antigen probes, the highly fluorescent cells were sorted by using a high-speed cell sorter, and these cells were reused without regeneration in the next round of sorting. After repeating this sorting, the positive clones were completely enriched in several hours. Thus, we screened the library against three viral antigens, including the H1N1 influenza virus, Hepatitis B virus, and Foot-and-mouth disease virus. Finally, the potential antibody candidates, which show K(D values between 10 and 100 nM against the target antigens, could be successfully isolated even though the library was relatively small (∼ 10(6. These results show that repeated FACS screening without regeneration of the sorted cells can be a powerful method when a rapid response to a spreading disease is required.

Chromatin maturation depends on continued DNA-replication

International Nuclear Information System (INIS)

Schlaeger, E.J.; Puelm, W.; Knippers, R.

1983-01-01

The structure of [ 3 H]thymidine pulse-labeled chromatin in lymphocytes differs from that of non-replicating chromatin by several operational criteria which are related to the higher nuclease sensitivity of replicating chromatin. These structural features of replicating chromatin rapidly disappear when the [ 3 H]thymidine pulse is followed by a chase in the presence of an excess of non-radioactive thymidine. However, when the rate of DNA replication is reduced, as in cycloheximide-treated lymphocytes, chromatin maturation is retarded. No chromatin maturation is observed when nuclei from pulse-labeled lymphocytes are incubated in vitro in the absence of DNA precursors. In contrast, when these nuclei are incubated under conditions known to be optimal for DNA replication, the structure of replicating chromatin is efficiently converted to that of 'mature', non-replicating chromatin. The authors conclude that the properties of nascent DNA and/or the distance from the replication fork are important factors in chromatin maturation. (Auth.)

Rapid Analysis of Copper Ore in Pre-Smelter Head Flow Slurry by Portable X-ray Fluorescence.

Science.gov (United States)

Burnett, Brandon J; Lawrence, Neil J; Abourahma, Jehad N; Walker, Edward B

2016-05-01

Copper laden ore is often concentrated using flotation. Before the head flow slurry can be smelted, it is important to know the concentration of copper and contaminants. The concentration of copper and other elements fluctuate significantly in the head flow, often requiring modification of the concentrations in the slurry prior to smelting. A rapid, real-time analytical method is needed to support on-site optimization of the smelter feedstock. A portable, handheld X-ray fluorescence spectrometer was utilized to determine the copper concentration in a head flow suspension at the slurry origin. The method requires only seconds and is reliable for copper concentrations of 2.0-25%, typically encountered in such slurries. © The Author(s) 2016.

A simple and rapid method for measurement of 10B-para-boronophenylalanine in the blood for boron neutron capture therapy using fluorescence spectrophotometry

International Nuclear Information System (INIS)

Kashino, Genro; Fukutani, Satoshi; Suzuki, Minoru

2009-01-01

10 B deriving from 10 B-para-boronophenylalanine (BPA) and 10 B-borocaptate sodium (BSH) have been detected in blood samples of patients undergoing boron neutron capture therapy (BNCT) using prompt gamma ray spectrometer or Inductively Coupled Plasma (ICP) method, respectively. However, the concentration of each compound cannot be ascertained because boron atoms in both molecules are the target in these assays. Here, we propose a simple and rapid method to measure only BPA by detecting fluorescence based on the characteristics of phenylalanine. 10 B concentrations of blood samples from human or mice were estimated by the fluorescence intensities at 275 nm of a BPA excited by light of wavelength 257 nm using a fluorescence spectrophotometer. The relationship between fluorescence to increased BPA concentration showed a positive linear correlation. Moreover, we established an adequate condition for BPA measurement in blood samples containing BPA, and the estimated 10 B concentrations of blood samples derived from BPA treated mice were similar between the values obtained by our method and those by ICP method. This new assay will be useful to estimate BPA concentration in blood samples obtained from patients undergoing BNCT especially in a combination use of BSH and BPA. (author)

A Fluorescent Tile DNA Diagnocode System for In Situ Rapid and Selective Diagnosis of Cytosolic RNA Cancer Markers

Science.gov (United States)

Park, Kyung Soo; Shin, Seung Won; Jang, Min Su; Shin, Woojung; Yang, Kisuk; Min, Junhong; Cho, Seung-Woo; Oh, Byung-Keun; Bae, Jong Wook; Jung, Sunghwan; Choi, Jeong-Woo; Um, Soong Ho

2015-01-01

Accurate cancer diagnosis often requires extraction and purification of genetic materials from cells, and sophisticated instrumentations that follow. Otherwise in order to directly treat the diagnostic materials to cells, multiple steps to optimize dose concentration and treatment time are necessary due to diversity in cellular behaviors. These processes may offer high precision but hinder fast analysis of cancer, especially in clinical situations that need rapid detection and characterization of cancer. Here we present a novel fluorescent tile DNA nanostructure delivered to cancer cytosol by employing nanoparticle technology. Its structural anisotropicity offers easy manipulation for multifunctionalities, enabling the novel DNA nanostructure to detect intracellular cancer RNA markers with high specificity within 30 minutes post treatment, while the nanoparticle property bypasses the requirement of treatment optimization, effectively reducing the complexity of applying the system for cancer diagnosis. Altogether, the system offers a precise and rapid detection of cancer, suggesting the future use in the clinical fields. PMID:26678430

X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Ray, N.B.

1977-01-01

The principle, instrument and procedure of X-ray fluorescence spectrometry are described. It is a rapid, simple and sensitive method for the trace analysis of elements from sodium to uranium in powder, liquid or metal samples. (M.G.B.)

Rapid methods for multi-elemental X-ray fluorescence analysis using excitation isotope sources and Si(Li)-semiconductor detector

International Nuclear Information System (INIS)

Zhuravleva, E.L.

1980-01-01

Some rapid methods using an unique calibration curve have been developed for multi-elemental X-ray fluorescence analysis of thin and thick layers of various samples having low contents of heavy elements. The matrix absorption effect in thick samples is taken into account according to the scattered radiation.The similar method using a unique calibration curve for determination of low contents of trace elements in thin layers without account of matrix effect is proposed. The results on the intercomposition run soil-5 are in good agreement with the data obtained in different laboratories. The errors of the method are 10 %; in a case of peak superposition - 15 %

Stink Bug Feeding Induces Fluorescence in Developing Cotton Bolls

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Toews Michael D

2011-08-01

Full Text Available Abstract Background Stink bugs (Hemiptera: Pentatomidae comprise a critically important insect pest complex affecting 12 major crops worldwide including cotton. In the US, stink bug damage to developing cotton bolls causes boll abscission, lint staining, reduced fiber quality, and reduced yields with estimated losses ranging from 10 to 60 million dollars annually. Unfortunately, scouting for stink bug damage in the field is laborious and excessively time consuming. To improve scouting accuracy and efficiency, we investigated fluorescence changes in cotton boll tissues as a result of stink bug feeding. Results Fluorescent imaging under long-wave ultraviolet light showed that stink bug-damaged lint, the inner carpal wall, and the outside of the boll emitted strong blue-green fluorescence in a circular region near the puncture wound, whereas undamaged tissue emissions occurred at different wavelengths; the much weaker emission of undamaged tissue was dominated by chlorophyll fluorescence. We further characterized the optimum emission and excitation spectra to distinguish between stink bug damaged bolls from undamaged bolls. Conclusions The observed characteristic fluorescence peaks associated with stink bug damage give rise to a fluorescence-based method to rapidly distinguish between undamaged and stink bug damaged cotton bolls. Based on the fluorescent fingerprint, we envision a fluorescence reflectance imaging or a fluorescence ratiometric device to assist pest management professionals with rapidly determining the extent of stink bug damage in a cotton field.

Compact point-detection fluorescence spectroscopy system for quantifying intrinsic fluorescence redox ratio in brain cancer diagnostics

Science.gov (United States)

Liu, Quan; Grant, Gerald; Li, Jianjun; Zhang, Yan; Hu, Fangyao; Li, Shuqin; Wilson, Christy; Chen, Kui; Bigner, Darell; Vo-Dinh, Tuan

2011-03-01

We report the development of a compact point-detection fluorescence spectroscopy system and two data analysis methods to quantify the intrinsic fluorescence redox ratio and diagnose brain cancer in an orthotopic brain tumor rat model. Our system employs one compact cw diode laser (407 nm) to excite two primary endogenous fluorophores, reduced nicotinamide adenine dinucleotide, and flavin adenine dinucleotide. The spectra were first analyzed using a spectral filtering modulation method developed previously to derive the intrinsic fluorescence redox ratio, which has the advantages of insensitivty to optical coupling and rapid data acquisition and analysis. This method represents a convenient and rapid alternative for achieving intrinsic fluorescence-based redox measurements as compared to those complicated model-based methods. It is worth noting that the method can also extract total hemoglobin concentration at the same time but only if the emission path length of fluorescence light, which depends on the illumination and collection geometry of the optical probe, is long enough so that the effect of absorption on fluorescence intensity due to hemoglobin is significant. Then a multivariate method was used to statistically classify normal tissues and tumors. Although the first method offers quantitative tissue metabolism information, the second method provides high overall classification accuracy. The two methods provide complementary capabilities for understanding cancer development and noninvasively diagnosing brain cancer. The results of our study suggest that this portable system can be potentially used to demarcate the elusive boundary between a brain tumor and the surrounding normal tissue during surgical resection.

Dynamic fluorescence imaging with molecular agents for cancer detection

Science.gov (United States)

Kwon, Sun Kuk

Non-invasive dynamic optical imaging of small animals requires the development of a novel fluorescence imaging modality. Herein, fluorescence imaging is demonstrated with sub-second camera integration times using agents specifically targeted to disease markers, enabling rapid detection of cancerous regions. The continuous-wave fluorescence imaging acquires data with an intensified or an electron-multiplying charge-coupled device. The work presented in this dissertation (i) assessed dose-dependent uptake using dynamic fluorescence imaging and pharmacokinetic (PK) models, (ii) evaluated disease marker availability in two different xenograft tumors, (iii) compared the impact of autofluorescence in fluorescence imaging of near-infrared (NIR) vs. red light excitable fluorescent contrast agents, (iv) demonstrated dual-wavelength fluorescence imaging of angiogenic vessels and lymphatics associated with a xenograft tumor model, and (v) examined dynamic multi-wavelength, whole-body fluorescence imaging with two different fluorescent contrast agents. PK analysis showed that the uptake of Cy5.5-c(KRGDf) in xenograft tumor regions linearly increased with doses of Cy5.5-c(KRGDf) up to 1.5 nmol/mouse. Above 1.5 nmol/mouse, the uptake did not increase with doses, suggesting receptor saturation. Target to background ratio (TBR) and PK analysis for two different tumor cell lines showed that while Kaposi's sarcoma (KS1767) exhibited early and rapid uptake of Cy5.5-c(KRGDf), human melanoma tumors (M21) had non-significant TBR differences and early uptake rates similar to the contralateral normal tissue regions. The differences may be due to different compartment location of the target. A comparison of fluorescence imaging with NIR vs. red light excitable fluorescent dyes demonstrates that NIR dyes are associated with less background signal, enabling rapid tumor detection. In contrast, animals injected with red light excitable fluorescent dyes showed high autofluorescence. Dual

Laser induced fluorescence technique for detecting organic matter in East China Sea

Science.gov (United States)

Chen, Peng; Wang, Tianyu; Pan, Delu; Huang, Haiqing

2017-10-01

A laser induced fluorescence (LIF) technique for fast diagnosing chromophoric dissolved organic matter (CDOM) in water is discussed. We have developed a new field-portable laser fluorometer for rapid fluorescence measurements. In addtion, the fluorescence spectral characteristics of fluorescent constituents (e.g., CDOM, chlorophyll-a) were analyzed with a spectral deconvolution method of bi-Gaussian peak function. In situ measurements by the LIF technique compared well with values measured by conventional spectrophotometer method in laboratory. A significant correlation (R2 = 0.93) was observed between fluorescence by the technique and absorption by laboratory spectrophotometer. Influence of temperature variation on LIF measurement was investigated in lab and a temperature coefficient was deduced for fluorescence correction. Distributions of CDOM fluorescence measured using this technique in the East China Sea coast were presented. The in situ result demonstrated the utility of the LIF technique for rapid detecting dissolved organic matter.

Comparison of Xpert Flu rapid nucleic acid testing with rapid antigen testing for the diagnosis of influenza A and B.

Science.gov (United States)

DiMaio, Michael A; Sahoo, Malaya K; Waggoner, Jesse; Pinsky, Benjamin A

2012-12-01

Influenza infections are associated with thousands of hospital admissions and deaths each year. Rapid detection of influenza is important for prompt initiation of antiviral therapy and appropriate patient triage. In this study the Cepheid Xpert Flu assay was compared with two rapid antigen tests, BinaxNOW Influenza A & B and BD Directigen EZ Flu A+B, as well as direct fluorescent antibody testing for the rapid detection of influenza A and B. Using real-time, hydrolysis probe-based, reverse transcriptase PCR as the reference method, influenza A sensitivity was 97.3% for Xpert Flu, 95.9% for direct fluorescent antibody testing, 62.2% for BinaxNOW, and 71.6% for BD Directigen. Influenza B sensitivity was 100% for Xpert Flu and direct fluorescent antibody testing, 54.5% for BinaxNOW, and 48.5% for BD Directigen. Specificity for influenza A was 100% for Xpert Flu, BinaxNOW, and BD Directigen, and 99.2% for direct fluorescent antibody testing. All methods demonstrated 100% specificity for influenza B. These findings support the use of the Xpert Flu assay in settings requiring urgent diagnosis of influenza A and B. Copyright © 2012 Elsevier B.V. All rights reserved.

Fluorescence immunoassay for detecting periodontal bacterial pathogens in plaque.

OpenAIRE

Wolff, L F; Anderson, L; Sandberg, G P; Aeppli, D M; Shelburne, C E

1991-01-01

A particle concentration fluorescence immunoassay has been modified into a bacterial concentration fluorescence immunoassay (BCFIA) to rapidly detect periodontopathic bacteria in human plaque samples. The BCFIA utilizes fluorescently tagged monoclonal antibodies (MAbs) directed against the lipopolysaccharide of selected gram-negative plaque bacteria. Microorganisms closely associated with periodontal disease that can be identified in plaque with the BCFIA include Porphyromonas gingivalis, Bac...

Problems of fluorescent imaging and its solution using nanofluorophores. Part I: Advantages of fluorescent nanoparticles over conventional organic fluorophores

International Nuclear Information System (INIS)

Zhelev, Z.; Hadjidekov, G.; Zlateva, G.; Spasov, L.; Bakalova, R.

2011-01-01

The application of fluorescence in deep-tissue imaging is rapidly expanding in fast several years. The progress in fluorescent molecular probes and fluorescent imaging techniques gives an opportunity to detect single cells and even molecules in live organisms. The highly sensitive and high-speed fluorescent molecular sensors and detection devices allow the application of fluorescence in functional imaging. With development of novel bright fluorophores based on nano-technologies and fluorescence scanners with high spatial and temporal resolution, the fluorescent imaging has a potential to become an alternative of the other non-invasive imaging techniques as magnetic resonance imaging, positron-emission tomography, X-ray, computing tomography. This review outlines the current status and future trends of fluorescent nanoparticles - quantum dots (QDs), as a new generation of fluorophores in experimental and pre-clinical fluorescent imaging diagnostic. Part 1 focuses on the advantages of quantum dots over conventional organic fluorophores and defines the major requirements to the 'perfect' fluorophore for fluorescent deep-tissue imaging diagnostic. The analysis is based on the limitations of fluorescent imaging in vivo and overcome by using quantum dots

Imaging metals in proteins by combining electrophoresis with rapid x-ray fluorescence mapping

International Nuclear Information System (INIS)

Finney, L.; Chishti, Y.; Khare, T.; Giometti, C.; Levina, A.; Lay, P.A.; Vogt, S.

2010-01-01

Growing evidence points toward a very dynamic role for metals in biology. This suggests that physiological circumstance may mandate metal ion redistribution among ligands. This work addresses a critical need for technology that detects, identifies, and measures the metal-containing components of complex biological matrixes. We describe a direct, user-friendly approach for identifying and quantifying metal?protein adducts in complex samples using native- or SDS-PAGE, blotting, and rapid synchrotron X-ray fluorescence mapping with micro-XANES (X-ray absorption near-edge structure) of entire blots. The identification and quantification of each metal bound to a protein spot has been demonstrated, and the technique has been applied in two exemplary cases. In the first, the speciation of the in vitro binding of exogenous chromium to blood serum proteins was influenced markedly by both the oxidation state of chromium exposed to the serum proteins and the treatment conditions, which is of relevance to the biochemistry of Cr dietary supplements. In the second case, in vivo changes in endogenous metal speciation were examined to probe the influence of oxygen depletion on iron speciation in Shewanella oneidensis.

Rapid and quantitative detection of zoonotic influenza A virus infection utilizing coumarin-derived dendrimer-based fluorescent immunochromatographic strip test (FICT).

Science.gov (United States)

Yeo, Seon-Ju; Huong, Dinh Thi; Hong, Nguyen Ngoc; Li, Chun-Ying; Choi, Kyunghan; Yu, Kyoungsik; Choi, Du-Young; Chong, Chom-Kyu; Choi, Hak Soo; Mallik, Shyam Kumar; Kim, Hak Sung; Sung, Haan Woo; Park, Hyun

2014-01-01

Great efforts have been made to develop robust signal-generating fluorescence materials which will help in improving the rapid diagnostic test (RDT) in terms of sensitivity and quantification. In this study, we developed coumarin-derived dendrimer-based fluorescent immunochromatographic strip test (FICT) assay with enhanced sensitivity as a quantitative diagnostic tool in typical RDT environments. The accuracy of the proposed FICT was compared with that of dot blot immunoassay techniques and conventional RDTs. Through conjugation of coumarin-derived dendrimers with latex beads, fluorescent emission covering broad output spectral ranges was obtained which provided a distinct advantage of easy discrimination of the fluorescent emission of the latex beads with a simple insertion of a long-pass optical filter away from the excitation wavelength. The newly developed FICT assay was able to detect 100 ng/10 μL of influenza A nucleoprotein (NP) antigen within 5 minutes, which corresponded to 2.5-fold higher sensitivity than that of the dot blot immunoassay or conventional RDTs. Moreover, the FICT assay was confirmed to detect at least four avian influenza A subtypes (H5N3, H7N1, H7N7, and H9N2). On applying the FICT to the clinical swab samples infected with respiratory viruses, our FICT assay was confirmed to differentiate influenza H1N1 infection from other respiratory viral diseases. These data demonstrate that the proposed FICT assay is able to detect zoonotic influenza A viruses with a high sensitivity, and it enables the quantitation of the infection intensity by providing the numerical diagnostic values; thus demonstrating enhanced detectability of influenza A viruses.

Centrioles initiate cilia assembly but are dispensable for maturation and maintenance in C. elegans.

Science.gov (United States)

Serwas, Daniel; Su, Tiffany Y; Roessler, Max; Wang, Shaohe; Dammermann, Alexander

2017-06-05

Cilia are cellular projections that assemble on centriole-derived basal bodies. While cilia assembly is absolutely dependent on centrioles, it is not known to what extent they contribute to downstream events. The nematode C. elegans provides a unique opportunity to address this question, as centrioles do not persist at the base of mature cilia. Using fluorescence microscopy and electron tomography, we find that centrioles degenerate early during ciliogenesis. The transition zone and axoneme are not completely formed at this time, indicating that cilia maturation does not depend on intact centrioles. The hydrolethalus syndrome protein HYLS-1 is the only centriolar protein known to remain at the base of mature cilia and is required for intraflagellar transport trafficking. Surprisingly, targeted degradation of HYLS-1 after initiation of ciliogenesis does not affect ciliary structures. Taken together, our results indicate that while centrioles are essential to initiate cilia formation, they are dispensable for cilia maturation and maintenance. © 2017 Serwas et al.

On gonadic maturation and reproductive strategy in deep-sea benthic octopus Graneledone macrotyla

Science.gov (United States)

Guerra, Ángel; Sieiro, María Pilar; Roura, Álvaro; Portela, Julio M.; del Río, José Luís

2013-09-01

The new information reported in this paper is based on five maturing and mature females of the large-tuberculate octopus Graneledone macrotyla. These specimens were caught in bottom trawl surveys ATLANTIS 2009 (February 24 to April 1, 2009) and ATLANTIS 2010 (March 9 to April 5, 2010) carried out off the Argentinean Economic Exclusive Zone. Capture depth ranged from 475 to 921 m and sea bottom temperature between 2.8 and 3.1 °C. Development of the complex ovary, oviducts, and oviducal glands during gonadic maturation is described. The absence of spermathecae in the oviducal glands and the presence of fertilized eggs inside the ovary suggested that fertilization took place within the ovary. Histological techniques showed the presence of four types of oocytes. Maturing oocyte size-frequency distribution was polymodal. Fluorescence reaction showed that atresia occurred in both early and later oocyte maturation stages. Atresia affected 48-55 % of the initial number of oocytes. The maximum observed potential fecundity was estimated at 250-300 eggs. G. macrotyla showed a group-synchronous ovulation pattern, regulative atresia, and a batching spawning pattern with a few egg batches spawned intermittently over an extended period of spawning.

Correlation between dental maturity and cervical vertebral maturity.

Science.gov (United States)

Chen, Jianwei; Hu, Haikun; Guo, Jing; Liu, Zeping; Liu, Renkai; Li, Fan; Zou, Shujuan

2010-12-01

The aim of this study was to investigate the association between dental and skeletal maturity. Digital panoramic radiographs and lateral skull cephalograms of 302 patients (134 boys and 168 girls, ranging from 8 to 16 years of age) were examined. Dental maturity was assessed by calcification stages of the mandibular canines, first and second premolars, and second molars, whereas skeletal maturity was estimated by the cervical vertebral maturation (CVM) stages. The Spearman rank-order correlation coefficient was used to measure the association between CVM stage and dental calcification stage of individual teeth. The mean chronologic age of girls was significantly lower than that of boys in each CVM stage. The Spearman rank-order correlation coefficients between dental maturity and cervical vertebral maturity ranged from 0.391 to 0.582 for girls and from 0.464 to 0.496 for boys (P cervical vertebral maturation stage. The development of the mandibular second molar in females and that of the mandibular canine in males had the strongest correlations with cervical vertebral maturity. Therefore, it is practical to consider the relationship between dental and skeletal maturity when planning orthodontic treatment. Copyright © 2010 Mosby, Inc. All rights reserved.

Spiculogenesis in the siliceous sponge Lubomirskia baicalensis studied with fluorescent staining.

Science.gov (United States)

Annenkov, Vadim V; Danilovtseva, Elena N

2016-04-01

Siliceous sponges are the most primitive multicellular animals whose skeleton consists of spicules - needle-like constructions from silicon dioxide surrounding organic axial filaments. Mechanisms of spicule formation have been intensively studied due to the high ecological importance of sponges and their interest to materials science. Light and electron microscopy are not appropriate enough to display the process from silicon-enriched cells to mature spicules because of composite structure of the sponge tissues. In this article, spiculogenesis in the siliceous sponge has been studied for the first time with the use of fluorescent microscopy. Fluorescent vital dye NBD-N2 was applied to stain growing siliceous structures in the sponge and primmorph cell system. The main stages of spicule growth in the fresh-water sponge Lubomirskia baicalensis (Pallas, 1773) were visualized: silicon accumulation in sclerocytes; formation of an organic filament protruding from the cell; further elongation of the filament and growth of the spicule in a spindle-like form with enlargement in the center; merger with new sclerocytes and formation of the mature spicule. Fluorescent microscopy combined with SEM allows us to overcome the virtual differentiation between intra- and extracellular mechanisms of spicule growth. The growing spicule can capture silicic acid from the extracellular space and merge with new silicon-enriched cells. Visualization of the growing spicules with the fluorescent dye allows us to monitor sponge viability in ecological or toxicological experiments and to apply genomic, proteomic and biochemical techniques. Copyright © 2016 Elsevier Inc. All rights reserved.

Rapid quantification of viable Legionella in nuclear cooling tower waters using filter cultivation, fluorescent in situ hybridization and solid-phase cytometry.

Science.gov (United States)

Baudart, J; Guillaume, C; Mercier, A; Lebaron, P; Binet, M

2015-05-01

To develop a rapid and sensitive method to quantify viable Legionella spp. in cooling tower water samples. A rapid, culture-based method capable of quantifying as few as 600 Legionella microcolonies per litre within 2 days in industrial waters was developed. The method combines a short cultivation step of microcolonies on GVPC agar plate, specific detection of Legionella cells by a fluorescent in situ hybridization (FISH) approach, and a sensitive enumeration using a solid-phase cytometer. Following optimization of the cultivation conditions, the qualitative and quantitative performance of the method was assessed and the method was applied to 262 nuclear power plant cooling water samples. The performance of this method was in accordance with the culture method (NF-T 90-431) for Legionella enumeration. The rapid detection of viable Legionella in water is a major concern to the effective monitoring of this pathogenic bacterium in the main water sources involved in the transmission of legionellosis infection (Legionnaires' disease). The new method proposed here appears to be a robust, efficient and innovative means for rapidly quantifying cultivable Legionella in cooling tower water samples within 48 h. © 2015 The Society for Applied Microbiology.

Maturity and maturity models in lean construction

Directory of Open Access Journals (Sweden)

Claus Nesensohn

2014-03-01

Full Text Available In recent years there has been an increasing interest in maturity models in management-related disciplines; which reflects a growing recognition that becoming more mature and having a model to guide the route to maturity can help organisations in managing major transformational change. Lean Construction (LC is an increasingly important improvement approach that organisations seek to embed. This study explores how to apply the maturity models to LC. Hence the attitudes, opinions and experiences of key industry informants with high levels of knowledge of LC were investigated. To achieve this, a review of maturity models was conducted, and data for the analysis was collected through a sequential process involving three methods. First a group interview with seven key informants. Second a follow up discussion with the same individuals to investigate some of the issues raised in more depth. Third an online discussion held via LinkedIn in which members shared their views on some of the results. Overall, we found that there is a lack of common understanding as to what maturity means in LC, though there is general agreement that the concept of maturity is a suitable one to reflect the path of evolution for LC within organisations.

Rapid-prenatal diagnosis through fluorescence in situ hybridization for preventing aneuploidy related birth defects.

Science.gov (United States)

Fauzdar, Ashish; Chowdhry, Mohit; Makroo, R N; Mishra, Manoj; Srivastava, Priyanka; Tyagi, Richa; Bhadauria, Preeti; Kaul, Anita

2013-01-01

Women with high-risk pregnancies are offered prenatal diagnosis through amniocentesis for cytogenetic analysis of fetal cells. The aim of this study was to evaluate the effectiveness of the rapid fluorescence in situ hybridization (FISH) technique for detecting numerical aberrations of chromosomes 13, 21, 18, X and Y in high-risk pregnancies in an Indian scenario. A total of 163 samples were received for a FISH and/or a full karyotype for prenatal diagnosis from high-risk pregnancies. In 116 samples both conventional culture techniques for getting karyotype through G-banding techniques were applied in conjunction to FISH test using the AneuVysion kit (Abbott Molecular, Inc.), following standard recommended protocol to compare the both the techniques in our setup. Out of 116 patients, we got 96 normal for the five major chromosome abnormality and seven patients were found to be abnormal (04 trisomy 21, 02 monosomy X, and 01 trisomy 13) and all the FISH results correlated with conventional cytogenetics. To summarize the results of total 163 patients for the major chromosomal abnormalities analyzed by both/or cytogenetics and FISH there were 140 (86%) normal, 9 (6%) cases were abnormal and another 4 (2.5%) cases were suspicious mosaic and 10 (6%) cases of culture failure. The diagnostic detection rate with FISH in 116 patients was 97.5%. There were no false-positive and false-negative autosomal or sex chromosomal results, within our established criteria for reporting FISH signals. Rapid FISH is a reliable and prompt method for detecting numerical chromosomal aberrations and has now been implemented as a routine diagnostic procedure for detection of fetal aneuploidy in India.

Rapid fluorescence assay for Sudan dyes using polyethyleneimine-coated copper nanoclusters

International Nuclear Information System (INIS)

Ling, Yu; Li, Jia Xing; Li, Nian Bing; Luo, Hong Qun; Qu, Fei

2014-01-01

We report that the intensity of the blue fluorescence of copper nanoclusters coated with polyethyleneimine (PEI) is strongly reduced in the presence of the food dyestuffs Sudan I-IV. This finding was exploited in a label-free fluorescence assay for these Sudan dyes both in ethanol and aqueous solutions. The PEI-capped nanoclusters have an average diameter of 1.8 nm and are displaying, under 355 nm excitation, a blue emission at 480 nm that matches the absorption bands of the Sudan dyes. The clusters are stable in solution for at least 1 month. Under optimum conditions, this assay can be applied to the quantification of the dyes Sudan I, II, III, and IV, respectively, in the 0.1−30, 0.1–30, 0.1–25, and 0.1–25 μM concentration ranges, and the detection limits (3σ/slope) are 65, 70, 45, and 50 nM, respectively. The capability of reducing the fluorescence of the PEI-capped copper nanoclusters is directly related to the number of the functional groups in that Sudan III and IV give lower detection limits. This analytical scheme exhibits a remarkably high selectivity for the Sudan dyes over potentially interfering substances. The method was successfully applied to determine Sudan I, II, III, and IV in hot chilli powder. (author)

A novel monodisperse SiO2@C-dot for the rapid and facile identification of latent fingermarks using self-quenching resistant solid-state fluorescence.

Science.gov (United States)

Peng, Di; Liu, Xiang; Huang, Mengjun; Wang, Dan; Liu, Renlong

2018-04-24

Solid powder fluorescence shows great potential for application in medicine, biology, and engineering, especially in the identification of latent fingermarks in forensic science. However, conventional developing methods suffer from some drawbacks, such as low contrast, low sensitivity, low selectivity, and high toxicity. To conquer these challenges, novel SiO2@C-dot microspheres were prepared via a facile one-pot hydrothermal method by using citric acid as a carbon source and aminosilane as a nitrogen source. Interestingly, the results showed that the resultant powders possess good monodispersity, high fluorescence emission, and resistance to self-quenching. Additionally, the mechanism for the solid-state fluorescence of SiO2@C-dot compounds was also investigated. More importantly, the fingermarks on various surfaces, including transparent glasses, ceramic tiles, transparent plastics, aluminum alloys, plastic cards, painted woods, artificial leathers, and Chinese paper money, developed by the powders have indicated well-defined papillary ridges under a 365 nm UV lamp. The novel strategy of using monodisperse SiO2@C-dot microspheres as a fluorescent label for developing latent fingermarks showed greater advantages compared to conventional methods, which was also demonstrated using the automatic fingerprint identification system. It is simple, rapid, low-cost, nontoxic, and effective, and is expected to be a promising alternative for the development of latent fingerprints in forensic science.

Do farmers rapidly adapt to past growing conditions by sowing different proportions of early and late maturing cereals and cultivars?

Directory of Open Access Journals (Sweden)

Pirjo Peltonen-Sainio

2013-10-01

Full Text Available In the short growing season of the northernmost European growing conditions, farmers are increasingly interested in expanding cultivation of later maturing crops at the expense of early maturing ones with lower yields. In this study we aimed to assess how the switching between spring cereals that differ in earliness was associated with different external factors. This was tested using unique datasets for regional cropping areas and cultivar use for the last 15 years. Early maturing barley was favored at the expense of later maturing wheat when a high number of days to crop maturity was required in the preceding year. In contrast, farmers reduced the barley area when a high number of cumulated degree days was required for a crop to mature in the previous year. A shift was recorded from early to late maturing cultivars. This study indicated that despite limited opportunities for farmers to alter land use, they readily responded to past conditions and used the knowledge gained for decision-making to reduce risk. This is a valuable operative model for studying adaptation to opportunities and constraints induced by climate change.

FRET microscopy autologous tumor lysate processing in mature dendritic cell vaccine therapy

Directory of Open Access Journals (Sweden)

Ridolfi Ruggero

2010-06-01

Full Text Available Abstract Background Antigen processing by dendritic cells (DC exposed to specific stimuli has been well characterized in biological studies. Nonetheless, the question of whether autologous whole tumor lysates (as used in clinical trials are similarly processed by these cells has not yet been resolved. Methods In this study, we examined the transfer of peptides from whole tumor lysates to major histocompatibility complex class II molecules (MHC II in mature dendritic cells (mDC from a patient with advanced melanoma. Tumor antigenic peptides-MHC II proximity was revealed by Förster Resonance Energy Transfer (FRET measurements, which effectively extends the application of fluorescence microscopy to the molecular level ( Results We detected significant energy transfer between donor and acceptor-labelled antibodies against HLA-DR at the membrane surface of mDC. FRET data indicated that fluorescent peptide-loaded MHC II molecules start to accumulate on mDC membranes at 16 hr from the maturation stimulus, steeply increasing at 22 hr with sustained higher FRET detected up to 46 hr. Conclusions The results obtained imply that the patient mDC correctly processed the tumor specific antigens and their display on the mDC surface may be effective for several days. These observations support the rationale for immunogenic efficacy of autologous tumor lysates.

Ultrasensitive near-infrared fluorescence-enhanced probe for in vivo nitroreductase imaging.

Science.gov (United States)

Li, Yuhao; Sun, Yun; Li, Jiachang; Su, Qianqian; Yuan, Wei; Dai, Yu; Han, Chunmiao; Wang, Qiuhong; Feng, Wei; Li, Fuyou

2015-05-20

Nitroreductase (NTR) can be overexpressed in hypoxic tumors, thus the selective and efficient detection of NTR is of great importance. To date, although a few optical methods have been reported for the detection of NTR in solution, an effective optical probe for NTR monitoring in vivo is still lacking. Therefore, it is necessary to develop a near-infrared (NIR) fluorescent detection probe for NTR. In this study, five NIR cyanine dyes with fluorescence reporting structure decorated with different nitro aromatic groups, Cy7-1-5, have been designed and explored for possible rapid detection of NTR. Our experimental results presented that only a para-nitro benzoate group modified cyanine probe (Cy7-1) could serve as a rapid NIR fluorescence-enhanced probe for monitoring and bioimaging of NTR. The structure-function relationship has been revealed by theoretical study. The linker connecting the detecting and fluorescence reporting groups and the nitro group position is a key factor for the formation of hydrogen bonds and spatial structure match, inducing the NTR catalytic ability enhancement. The in vitro response and mechanism of the enzyme-catalyzed reduction of Cy7-1 have been investigated through kinetic optical studies and other methods. The results have indicated that an electro-withdrawing group induced electron-transfer process becomes blocked when Cy7-1 is catalytically reduced to Cy7-NH2 by NTR, which is manifested in enhanced fluorescence intensity during the detection process. Confocal fluorescence imaging of hypoxic A549 cells has confirmed the NTR detection ability of Cy7-1 at the cellular level. Importantly, Cy7-1 can detect tumor hypoxia in a murine hypoxic tumor model, showing a rapid and significant enhancement of its NIR fluorescence characteristics suitable for fluorescence bioimaging. This method may potentially be used for tumor hypoxia diagnosis.

Rapid Determination of Enzyme Kinetics from Fluorescence: Overcoming the Inner Filter Effect

Science.gov (United States)

Palmier, Mark O.; Van Doren, Steven R.

2007-01-01

Fluorescence change is convenient for monitoring enzyme kinetics. Unfortunately, it looses linearity as the absorbance of the fluorescent substrate increases with concentration. When the sum of absorbance at excitation and emission wavelengths exceeds 0.08, this inner filtering effect (IFE) alters apparent initial velocities, Km, and kcat. The IFE distortion of apparent initial velocities can be corrected without doing fluorophore dilution assays. Using the substrate’s extinction coefficients at excitation and emission wavelengths, the inner filter effect can be modeled during curve fitting for more accurate Michaelis-Menten parameters. A faster and simpler approach is to derive kcat and Km from progress curves. Strategies to obtain reliable and reproducible estimates of kcat and Km from only two or three progress curves are illustrated using matrix metalloproteinase-12 and alkaline phosphatase. Accurate estimates of concentration of enzyme active sites and specificity constant kcat/Km (from one progress curve with [S] ≪ Km) confer accuracy, freedom of choices of [S], and robustness to kcat and Km globally fitted to a few progress curves. The economies of the progress curve approach make accurate kcat and Km more accessible from fluorescence measurements. PMID:17706587

Synthesis and Sensing Applications of Fluorescent 3-Cinnamoyl Coumarins

Directory of Open Access Journals (Sweden)

Preeti Yadav

2015-12-01

Full Text Available We have synthesized two novel fluorescent 3-(4-diethylaminocinnamoyl coumarins that exhibit fluorescence quenching upon exposure to a nerve agent simulant, diethylchlorophosphate (DCP, providing a basis for rapid and sensitive DCP chemosensing. Furthermore, these coumarin derivatives display two-photon fluorescence upon illumination with near-infrared laser pulses and their two-photon (TP absorption cross-section was evaluated. The potential for TP bio-imaging of these compounds was investigated by their cellular uptake in HeLa cells by TP confocal microscopy.

Rapid Simultaneous Amplification and Detection of the MBR/JH Chromosomal Translocation by Fluorescence Melting Curve Analysis

Science.gov (United States)

Bohling, Sandra D.; King, Thomas C.; Wittwer, Carl T.; Elenitoba-Johnson, Kojo S. J.

1999-01-01

Polymerase chain reaction (PCR) amplification and product analysis for the detection of chromosomal translocations, such as the t(14;18), has traditionally been a two-step process. PCR product detection has generally entailed gel electrophoresis and/or hybridization or sequencing for confirmation of assay specificity. Using a microvolume fluorimeter integrated with a thermal cycler and a PCR-compatible double-stranded DNA (dsDNA) binding fluorescent dye (SYBR Green I), we investigated the feasibility of simultaneous thermal amplification and detection of MBR/JH translocation products by fluorescence melting curve analysis. We analyzed DNA from 30 cases of lymphoproliferative disorders comprising 19 cases of previously documented MBR/JH-positive follicle center lymphoma and 11 reactive lymphadenopathies. The samples were coded and analyzed blindly for the presence of MBR/JH translocations by fluorescence melting curve analysis. We also performed dilutional assays using the MBR/JH-positive cell line SUDHL-6. Multiplex PCR for MBR/JH and β-globin was used to simultaneously assess sample adequacy. All (100%) of the 19 cases previously determined to be MBR/JH positive by conventional PCR analysis showed a characteristic sharp decrease in fluorescence at ∼90°C by melting curve analysis after amplification. Fluorescence melting peaks obtained by plotting the negative derivative of fluorescence over temperature (−dF/dT) versus temperature (T) showed melting temperatures (Tm) at 88.85 ± 1.15°C. In addition, multiplex assays using both MBR/JH and β-globin primers yielded easily distinguishable fluorescence melting peaks at ∼90°C and 81.2°C, respectively. Dilutional assays revealed that fluorescence melting curve analysis was more sensitive than conventional PCR and agarose gel electrophoresis with ultraviolet transillumination by as much as 100-fold. Simultaneous amplification and fluorescence melting curve analysis is a simple, reliable, and sensitive method

Females are the brighter sex: Differences in external fluorescence across sexes and life stages of a crab spider.

Science.gov (United States)

Brandt, Erin E; Masta, Susan E

2017-01-01

Fluorescence is increasingly recognized to be widespread in nature. In particular, some arachnids fluoresce externally, and in spiders the hemolymph fluoresces. In this study, we examined the external fluorescence and the fluorophores of different sexes and life stages of the crab spider Misumena vatia (Clerk 1757), a sit-and-wait predator that feeds on insects as they visit flowers. We designed novel instrumentation to measure external fluorescence in whole specimens. We found that although males and females possess internal fluorophores with similar properties, the external expression of fluorescence varies across sexes and life stages. Spiders fluoresce brightly as immatures. Females maintain their brightness to adulthood, whereas males become increasingly dim as they mature. We suggest that external fluorescence likely contributes to visual signaling in these animals, and that it differs between the sexes as a result of differences in foraging ecology and behavior.

An electronically tunable ultrafast laser source applied to fluorescence imaging and fluorescence lifetime imaging microscopy

International Nuclear Information System (INIS)

Dunsby, C; Lanigan, P M P; McGinty, J; Elson, D S; Requejo-Isidro, J; Munro, I; Galletly, N; McCann, F; Treanor, B; Oenfelt, B; Davis, D M; Neil, M A A; French, P M W

2004-01-01

Fluorescence imaging is used widely in microscopy and macroscopic imaging applications for fields ranging from biomedicine to materials science. A critical component for any fluorescence imaging system is the excitation source. Traditionally, wide-field systems use filtered thermal or arc-generated white light sources, while point scanning confocal microscope systems require spatially coherent (point-like) laser sources. Unfortunately, the limited range of visible wavelengths available from conventional laser sources constrains the design and usefulness of fluorescent probes in confocal microscopy. A 'hands-off' laser-like source, electronically tunable across the visible spectrum, would be invaluable for fluorescence imaging and provide new opportunities, e.g. automated excitation fingerprinting and in situ measurement of excitation cross-sections. Yet more information can be obtained using fluorescence lifetime imaging (FLIM), which requires that the light source be pulsed or rapidly modulated. We show how a white light continuum, generated by injecting femtosecond optical radiation into a micro-structured optical fibre, coupled with a simple prism-based tunable filter arrangement, can fulfil all these roles as a continuously electronically tunable (435-1150 nm) visible ultrafast light source in confocal, wide-field and FLIM systems

Tolerance of a knotted near infrared fluorescent protein to random circular permutation

Science.gov (United States)

Pandey, Naresh; Kuypers, Brianna E.; Nassif, Barbara; Thomas, Emily E.; Alnahhas, Razan N.; Segatori, Laura; Silberg, Jonathan J.

2016-01-01

Bacteriophytochrome photoreceptors (BphP) are knotted proteins that have been developed as near-infrared fluorescent protein (iRFP) reporters of gene expression. To explore how rearrangements in the peptides that interlace into the knot within the BphP photosensory core affect folding, we subjected iRFP to random circular permutation using an improved transposase mutagenesis strategy and screened for variants that fluoresce. We identified twenty seven circularly permuted iRFP that display biliverdin-dependent fluorescence in Escherichia coli. The variants with the brightest whole cell fluorescence initiated translation at residues near the domain linker and knot tails, although fluorescent variants were discovered that initiated translation within the PAS and GAF domains. Circularly permuted iRFP retained sufficient cofactor affinity to fluoresce in tissue culture without the addition of biliverdin, and one variant displayed enhanced fluorescence when expressed in bacteria and tissue culture. This variant displayed a similar quantum yield as iRFP, but exhibited increased resistance to chemical denaturation, suggesting that the observed signal increase arose from more efficient protein maturation. These results show how the contact order of a knotted BphP can be altered without disrupting chromophore binding and fluorescence, an important step towards the creation of near-infrared biosensors with expanded chemical-sensing functions for in vivo imaging. PMID:27304983

S - and N-alkylating agents diminish the fluorescence of fluorescent dye-stained DNA.

Science.gov (United States)

Giesche, Robert; John, Harald; Kehe, Kai; Schmidt, Annette; Popp, Tanja; Balzuweit, Frank; Thiermann, Horst; Gudermann, Thomas; Steinritz, Dirk

2017-01-25

Sulfur mustard (SM), a chemical warfare agent, causes DNA alkylation, which is believed to be the main cause of its toxicity. SM DNA adducts are commonly used to verify exposure to this vesicant. However, the required analytical state-of-the-art mass-spectrometry methods are complex, use delicate instruments, are not mobile, and require laboratory infrastructure that is most likely not available in conflict zones. Attempts have thus been made to develop rapid detection methods that can be used in the field. The analysis of SM DNA adducts (HETE-G) by immunodetection is a convenient and suitable method. For a diagnostic assessment, HETE-G levels must be determined in relation to the total DNA in the sample. Total DNA can be easily visualized by the use of fluorescent DNA dyes. This study examines whether SM and related compounds affect total DNA staining, an issue that has not been investigated before. After pure DNA was extracted from human keratinocytes (HaCaT cells), DNA was exposed to different S- and N-alkylating agents. Our experiments revealed a significant, dose-dependent decrease in the fluorescence signal of fluorescent dye-stained DNA after exposure to alkylating agents. After mass spectrometry and additional fluorescence measurements ruled out covalent modifications of ethidium bromide (EthBr) by SM, we assumed that DNA crosslinks caused DNA condensation and thereby impaired access of the fluorescent dyes to the DNA. DNA digestion by restriction enzymes restored fluorescence, a fact that strengthened our hypothesis. However, monofunctional agents, which are unable to crosslink DNA, also decreased the fluorescence signal. In subsequent experiments, we demonstrated that protons produced during DNA alkylation caused a pH decrease that was found responsible for the reduction in fluorescence. The use of an appropriate buffer system eliminated the adverse effect of alkylating agents on DNA staining with fluorescent dyes. An appropriate buffer system is thus

Characterization by fluorescence of dissolved organic matter in rural drinking water storage tanks in Morocco.

Science.gov (United States)

Aziz, Faissal; Ouazzani, Naaila; Mandi, Laila; Assaad, Aziz; Pontvianne, Steve; Poirot, Hélène; Pons, Marie-Noëlle

2018-04-01

Water storage tanks, fed directly from the river through opened channels, are particular systems used for water supply in rural areas in Morocco. The stored water is used as drinking water by the surrounding population without any treatment. UV-visible spectroscopy and fluorescence spectroscopy (excitation-emission matrices and synchronous fluorescence) have been tested as rapid methods to assess the quality of the water stored in the reservoirs as well as along the river feeding them. Synchronous fluorescence spectra (SFS50), collected with a difference of 50 nm between excitation and emission wavelengths, revealed a high tryptophan-like fluorescence, indicative of a pollution induced by untreated domestic and/or farm wastewater. The best correlations were obtained between the total SFS50 fluorescence and dissolved organic carbon (DOC) and biological oxygen demand, showing that the contribution of humic-like fluorescent substances cannot be neglected to rapidly assess reservoir water quality in terms of DOC by fluorescence spectroscopy.

A novel turn-on fluorescent strategy for sensing ascorbic acid using graphene quantum dots as fluorescent probe.

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Liu, Hua; Na, Weidan; Liu, Ziping; Chen, Xueqian; Su, Xingguang

2017-06-15

In this paper, a facile and rapid fluorescence turn-on assay for fluorescent detection of ascorbic acid (AA) was developed by using the orange emission graphene quantum dots (GQDs). In the presence of horse radish peroxidase (HRP) and hydrogen peroxide (H 2 O 2 ), catechol can be oxidized by hydroxyl radicals and converted to o-benzoquinone, which can significantly quench the fluorescence of GQDs. However, when AA present in the system, it can consume part of H 2 O 2 and hydroxyl radicals to inhibit the generation of o-benzoquinone, resulting in fluorescence recovery. Under the optimized experimental conditions, the fluorescence intensity was linearly correlated with the concentration of H 2 O 2 in the range of 3.33-500µM with a detection limit of 1.2µM. The linear detection for AA was in the range from 1.11 to 300µM with a detection limit of 0.32µM. The proposed method was applied to the determination of AA in human serum samples with satisfactory results. Copyright © 2017. Published by Elsevier B.V.

Structural and Maturational Covariance in Early Childhood Brain Development.

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Geng, Xiujuan; Li, Gang; Lu, Zhaohua; Gao, Wei; Wang, Li; Shen, Dinggang; Zhu, Hongtu; Gilmore, John H

2017-03-01

Brain structural covariance networks (SCNs) composed of regions with correlated variation are altered in neuropsychiatric disease and change with age. Little is known about the development of SCNs in early childhood, a period of rapid cortical growth. We investigated the development of structural and maturational covariance networks, including default, dorsal attention, primary visual and sensorimotor networks in a longitudinal population of 118 children after birth to 2 years old and compared them with intrinsic functional connectivity networks. We found that structural covariance of all networks exhibit strong correlations mostly limited to their seed regions. By Age 2, default and dorsal attention structural networks are much less distributed compared with their functional maps. The maturational covariance maps, however, revealed significant couplings in rates of change between distributed regions, which partially recapitulate their functional networks. The structural and maturational covariance of the primary visual and sensorimotor networks shows similar patterns to the corresponding functional networks. Results indicate that functional networks are in place prior to structural networks, that correlated structural patterns in adult may arise in part from coordinated cortical maturation, and that regional co-activation in functional networks may guide and refine the maturation of SCNs over childhood development. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Screening of HIV-1 Protease Using a Combination of an Ultra-High-Throughput Fluorescent-Based Assay and RapidFire Mass Spectrometry.

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Meng, Juncai; Lai, Ming-Tain; Munshi, Vandna; Grobler, Jay; McCauley, John; Zuck, Paul; Johnson, Eric N; Uebele, Victor N; Hermes, Jeffrey D; Adam, Gregory C

2015-06-01

HIV-1 protease (PR) represents one of the primary targets for developing antiviral agents for the treatment of HIV-infected patients. To identify novel PR inhibitors, a label-free, high-throughput mass spectrometry (HTMS) assay was developed using the RapidFire platform and applied as an orthogonal assay to confirm hits identified in a fluorescence resonance energy transfer (FRET)-based primary screen of > 1 million compounds. For substrate selection, a panel of peptide substrates derived from natural processing sites for PR was evaluated on the RapidFire platform. As a result, KVSLNFPIL, a new substrate measured to have a ~ 20- and 60-fold improvement in k cat/K m over the frequently used sequences SQNYPIVQ and SQNYPIV, respectively, was identified for the HTMS screen. About 17% of hits from the FRET-based primary screen were confirmed in the HTMS confirmatory assay including all 304 known PR inhibitors in the set, demonstrating that the HTMS assay is effective at triaging false-positives while capturing true hits. Hence, with a sampling rate of ~7 s per well, the RapidFire HTMS assay enables the high-throughput evaluation of peptide substrates and functions as an efficient tool for hits triage in the discovery of novel PR inhibitors. © 2015 Society for Laboratory Automation and Screening.

Clinical application of fluorescence in situ hybridization for prenatal diagnosis

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Shu-fang JIANG

2012-07-01

Full Text Available Objective To establish and optimize the procedures of fluorescence in situ hybridization（FISH）, and evaluate its clinical value in rapid prenatal diagnosis of fetal numerical abnormality of chromosomes 21, 18, 13, X, Y. Methods Amniotic fluid or fetal blood was sampled by routine invasive procedures. After the amniotic fluid cells or fetal blood cells were separated and sequentially processed with hypotonic solution, fixation solution, smear and high temperature, they were hybridized in situ with two panels of specific fluorescence probes to detect numerical abnormality of chromosomes 21, 18, 13, X, Y. All the samples were also cultured and analyzed for their karyotype by conventional methods. Results When it was used as a diagnostic criterion of chromosomal number that the fluorescence signals were observed in ≥90% cells, GLP 13/GLP 21 probe panel showed 2 green/2 red fluorescence signals and CSP18/CSP X/CSP Y probe panel showed 2 blue/2 yellow (female or 2 blue/1 yellow/1 red fluorescence signals (male under normal condition. The test reports of all 196 cases were sent out in 72-96 hours, and 7 cases of Down syndrome, 2 cases of trisomy 18 and 1 case of sex chromosomal numerical abnormality were detected, which were accordant with karyotype analysis results reported one month later. Conclusions FISH has potential for clinical application, and is applicable to rapid prenatal diagnosis of fetal numerical abnormality of chromosomes 21, 18, 13, X, Y. The rapid FISH, together with conventional karyotyping, offer a valuable means for prenatal diagnosis of fetal aneuploidies.

Ultrasensitive fluorescence immunoassay for detection of ochratoxin A using catalase-mediated fluorescence quenching of CdTe QDs

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Huang, Xiaolin; Zhan, Shengnan; Xu, Hengyi; Meng, Xianwei; Xiong, Yonghua; Chen, Xiaoyuan

2016-04-01

Herein, for the first time we report an improved competitive fluorescent enzyme linked immunosorbent assay (ELISA) for the ultrasensitive detection of ochratoxin A (OTA) by using hydrogen peroxide (H2O2)-induced fluorescence quenching of mercaptopropionic acid-modified CdTe quantum dots (QDs). In this immunoassay, catalase (CAT) was labeled with OTA as a competitive antigen to connect the fluorescence signals of the QDs with the concentration of the target. Through the combinatorial use of H2O2-induced fluorescence quenching of CdTe QDs as a fluorescence signal output and the ultrahigh catalytic activity of CAT to H2O2, our proposed method could be used to perform a dynamic linear detection of OTA ranging from 0.05 pg mL-1 to 10 pg mL-1. The half maximal inhibitory concentration was 0.53 pg mL-1 and the limit of detection was 0.05 pg mL-1. These values were approximately 283- and 300-folds lower than those of horseradish peroxidase (HRP)-based conventional ELISA, respectively. The reported method is accurate, highly reproducible, and specific against other mycotoxins in agricultural products as well. In summary, the developed fluorescence immunoassay based on H2O2-induced fluorescence quenching of CdTe QDs can be used for the rapid and highly sensitive detection of mycotoxins or haptens in food safety monitoring.Herein, for the first time we report an improved competitive fluorescent enzyme linked immunosorbent assay (ELISA) for the ultrasensitive detection of ochratoxin A (OTA) by using hydrogen peroxide (H2O2)-induced fluorescence quenching of mercaptopropionic acid-modified CdTe quantum dots (QDs). In this immunoassay, catalase (CAT) was labeled with OTA as a competitive antigen to connect the fluorescence signals of the QDs with the concentration of the target. Through the combinatorial use of H2O2-induced fluorescence quenching of CdTe QDs as a fluorescence signal output and the ultrahigh catalytic activity of CAT to H2O2, our proposed method could be used to

Small fluorescence-activating and absorption-shifting tag for tunable protein imaging in vivo.

Science.gov (United States)

Plamont, Marie-Aude; Billon-Denis, Emmanuelle; Maurin, Sylvie; Gauron, Carole; Pimenta, Frederico M; Specht, Christian G; Shi, Jian; Quérard, Jérôme; Pan, Buyan; Rossignol, Julien; Moncoq, Karine; Morellet, Nelly; Volovitch, Michel; Lescop, Ewen; Chen, Yong; Triller, Antoine; Vriz, Sophie; Le Saux, Thomas; Jullien, Ludovic; Gautier, Arnaud

2016-01-19

This paper presents Yellow Fluorescence-Activating and absorption-Shifting Tag (Y-FAST), a small monomeric protein tag, half as large as the green fluorescent protein, enabling fluorescent labeling of proteins in a reversible and specific manner through the reversible binding and activation of a cell-permeant and nontoxic fluorogenic ligand (a so-called fluorogen). A unique fluorogen activation mechanism based on two spectroscopic changes, increase of fluorescence quantum yield and absorption red shift, provides high labeling selectivity. Y-FAST was engineered from the 14-kDa photoactive yellow protein by directed evolution using yeast display and fluorescence-activated cell sorting. Y-FAST is as bright as common fluorescent proteins, exhibits good photostability, and allows the efficient labeling of proteins in various organelles and hosts. Upon fluorogen binding, fluorescence appears instantaneously, allowing monitoring of rapid processes in near real time. Y-FAST distinguishes itself from other tagging systems because the fluorogen binding is highly dynamic and fully reversible, which enables rapid labeling and unlabeling of proteins by addition and withdrawal of the fluorogen, opening new exciting prospects for the development of multiplexing imaging protocols based on sequential labeling.

Maturity group classification and maturity locus genotyping of early-maturing soybean varieties from high-latitude cold regions.

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Jia, Hongchang; Jiang, Bingjun; Wu, Cunxiang; Lu, Wencheng; Hou, Wensheng; Sun, Shi; Yan, Hongrui; Han, Tianfu

2014-01-01

With the migration of human beings, advances of agricultural sciences, evolution of planting patterns and global warming, soybeans have expanded to both tropical and high-latitude cold regions (HCRs). Unlike other regions, HCRs have much more significant and diverse photoperiods and temperature conditions over seasons or across latitudes, and HCR soybeans released there show rich diversity in maturity traits. However, HCR soybeans have not been as well classified into maturity groups (MGs) as other places. Therefore, it is necessary to identify MGs in HCRs and to genotype the maturity loci. Local varieties were collected from the northern part of Northeast China and the far-eastern region of Russia. Maturity group reference (MGR) soybeans of MGs MG000, MG00, and MG0 were used as references during field experiments. Both local varieties and MGR soybeans were planted for two years (2010-2011) in Heihe (N 50°15', E 127°27', H 168.5 m), China. The days to VE (emergence), R1 (beginning bloom) and R7 (beginning maturity) were recorded and statistically analyzed. Furthermore, some varieties were further genotyped at four molecularly-identified maturity loci E1, E2, E3 and E4. The HCR varieties were classified into MG0 or even more early-maturing. In Heihe, some varieties matured much earlier than MG000, which is the most early-maturing known MG, and clustered into a separate group. We designated the group as MG0000, following the convention of MGs. HCR soybeans had relatively stable days to beginning bloom from emergence. The HCR varieties diversified into genotypes of E1, E2, E3 and E4. These loci had different effects on maturity. HCRs diversify early-maturing MGs of soybean. MG0000, a new MG that matures much earlier than known MGs, was developed. HCR soybean breeding should focus more on shortening post-flowering reproductive growth. E1, E2, E3, and E4 function differentially.

Females are the brighter sex: Differences in external fluorescence across sexes and life stages of a crab spider.

Directory of Open Access Journals (Sweden)

Erin E Brandt

Full Text Available Fluorescence is increasingly recognized to be widespread in nature. In particular, some arachnids fluoresce externally, and in spiders the hemolymph fluoresces. In this study, we examined the external fluorescence and the fluorophores of different sexes and life stages of the crab spider Misumena vatia (Clerk 1757, a sit-and-wait predator that feeds on insects as they visit flowers. We designed novel instrumentation to measure external fluorescence in whole specimens. We found that although males and females possess internal fluorophores with similar properties, the external expression of fluorescence varies across sexes and life stages. Spiders fluoresce brightly as immatures. Females maintain their brightness to adulthood, whereas males become increasingly dim as they mature. We suggest that external fluorescence likely contributes to visual signaling in these animals, and that it differs between the sexes as a result of differences in foraging ecology and behavior.

Fluorogen-activating proteins: beyond classical fluorescent proteins

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Shengnan Xu

2018-05-01

Full Text Available Fluorescence imaging is a powerful technique for the real-time noninvasive monitoring of protein dynamics. Recently, fluorogen activating proteins (FAPs/fluorogen probes for protein imaging were developed. Unlike the traditional fluorescent proteins (FPs, FAPs do not fluoresce unless bound to their specific small-molecule fluorogens. When using FAPs/fluorogen probes, a washing step is not required for the removal of free probes from the cells, thus allowing rapid and specific detection of proteins in living cells with high signal-to-noise ratio. Furthermore, with different fluorogens, living cell multi-color proteins labeling system was developed. In this review, we describe about the discovery of FAPs, the design strategy of FAP fluorogens, the application of the FAP technology and the advances of FAP technology in protein labeling systems. KEY WORDS: Fluorogen activating proteins, Fluorogens, Genetically encoded sensors, Fluorescence imaging, Molecular imaging

[Laser induced fluorescence spectrum characteristics of common edible oil and fried cooking oil].

Science.gov (United States)

Mu, Tao-tao; Chen, Si-ying; Zhang, Yin-chao; Chen, He; Guo, Pan; Ge, Xian-ying; Gao, Li-lei

2013-09-01

In order to detect the trench oil the authors built a trench oil rapid detection system based on laser induced fluorescence detection technology. This system used 355 nm laser as excitation light source. The authors collected the fluorescence spectrum of a variety of edible oil and fried cooking oil (a kind of trench oil) and then set up a fluorescence spectrum database by taking advantage of the trench oil detection system It was found that the fluorescence characteristics of fried cooking oil and common edible oil were obviously different. Then it could easily realize the oil recognition and trench oil rapid detection by using principal component analysis and BP neural network, and the overall recognition rate could reach as high as 97.5%. Experiments showed that laser induced fluorescence spectrum technology was fast, non-contact, and highly sensitive. Combined with BP neural network, it would become a new technique to detect the trench oil.

A rapid-screening approach to detect and quantify microplastics based on fluorescent tagging with Nile Red

Science.gov (United States)

Maes, Thomas; Jessop, Rebecca; Wellner, Nikolaus; Haupt, Karsten; Mayes, Andrew G.

2017-03-01

A new approach is presented for analysis of microplastics in environmental samples, based on selective fluorescent staining using Nile Red (NR), followed by density-based extraction and filtration. The dye adsorbs onto plastic surfaces and renders them fluorescent when irradiated with blue light. Fluorescence emission is detected using simple photography through an orange filter. Image-analysis allows fluorescent particles to be identified and counted. Magnified images can be recorded and tiled to cover the whole filter area, allowing particles down to a few micrometres to be detected. The solvatochromic nature of Nile Red also offers the possibility of plastic categorisation based on surface polarity characteristics of identified particles. This article details the development of this staining method and its initial cross-validation by comparison with infrared (IR) microscopy. Microplastics of different sizes could be detected and counted in marine sediment samples. The fluorescence staining identified the same particles as those found by scanning a filter area with IR-microscopy.

A rapid, reliable method of evaluating growth and viability of intraerythrocytic protozoan hemoparasites using fluorescence flow cytometry.

Science.gov (United States)

Davis, W C; Wyatt, C R; Hamilton, M J; Goff, W L

1992-01-01

Fluorescence flow cytometry was employed to assess the potential of a vital dye, hydroethidine, for use in the detection and monitoring of the viability of hemoparasites in infected erythrocytes, using Babesia bovis as a model parasite. The studies demonstrated that hydroethidine is taken up by B. bovis and metabolically converted to the DNA binding fluorochrome, ethidium. Following uptake of the dye, erythrocytes containing viable parasites were readily distinguished and quantitated. Timed studies with the parasiticidal drug, Ganaseg, showed that it is possible to use the fluorochrome assay to monitor the effects of the drug on the rate of replication and viability of B. bovis in culture. The assay provides a rapid method for evaluation of the in vitro effect of drugs on hemoparasites and for analysis of the effect of various components of the immune response, such as lymphokines, monocyte products, antibodies, and effector cells (T, NK, LAK, ADCC) on the growth and viability of intraerythrocytic parasites.

A rapid, reliable method of evaluating growth and viability of intraerythrocytic protozoan hemoparasites using fluorescence flow cytometry

Directory of Open Access Journals (Sweden)

W. C. Davis

1992-01-01

Full Text Available Fluorescence flow cytometry was employed to assess the potential of a vital dye, hydroethiedine, for use in the detection and monitoring of the viability of hemoparasites in infected erythrocytes, using Babesia bovis as a model parasite. The studies demonstrated that hydroethidine is taken up by B. bovis and metabolically converted to the DNA binding fluorochrone, ethidium. Following uptake of the dye, erythrocytes contamine viable parasites were readily distinguished and quantitated. Timed studies with the parasiticidal drug, Ganaseg, showed that it is possible to use the fluorochrome assay to monitor the effects of the drug on the rate of replication and viability of B. bovis in culture. The assay provides a rapid method for evaluation of the in vitro effect of drugs on hemoparasites and for analysis of the effect of various components of the immune response, such as lymphokines, monocyte products, antibodies, and effector cells (T, NK, LAK, ADCC on the growth and viability of intraerythrocytic parasites.

Audiovisual Simultaneity Judgment and Rapid Recalibration throughout the Lifespan.

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Noel, Jean-Paul; De Niear, Matthew; Van der Burg, Erik; Wallace, Mark T

2016-01-01

Multisensory interactions are well established to convey an array of perceptual and behavioral benefits. One of the key features of multisensory interactions is the temporal structure of the stimuli combined. In an effort to better characterize how temporal factors influence multisensory interactions across the lifespan, we examined audiovisual simultaneity judgment and the degree of rapid recalibration to paired audiovisual stimuli (Flash-Beep and Speech) in a sample of 220 participants ranging from 7 to 86 years of age. Results demonstrate a surprisingly protracted developmental time-course for both audiovisual simultaneity judgment and rapid recalibration, with neither reaching maturity until well into adolescence. Interestingly, correlational analyses revealed that audiovisual simultaneity judgments (i.e., the size of the audiovisual temporal window of simultaneity) and rapid recalibration significantly co-varied as a function of age. Together, our results represent the most complete description of age-related changes in audiovisual simultaneity judgments to date, as well as being the first to describe changes in the degree of rapid recalibration as a function of age. We propose that the developmental time-course of rapid recalibration scaffolds the maturation of more durable audiovisual temporal representations.

Effect of Sex-linked Feathering Genes on Body Weight, Age At Sexual Maturity, Feed Intake and Subsequent Laying Performance of Baladi Chickens

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A. AI-Sobayel

1997-01-01

Full Text Available A total of 320 twenty week-old slow and rapid feathering Saudi Arabian Baladi pullers were used to assess the effect of sex-linked feathering genes on body weight, age at sexual maturity, feed intake and subsequent laying performance. Similar numbers of rapid feathering Leghorns pullets were included in the study for the purpose of comparison. The experimental birds of each genotypic group were randomly divided into four replicates and subjected to standard management practices. Slow feathering Baladi pullers had higher (P<0.05 adult body weight, rate of mortality, and feed intake and a similar age at sexual maturity but showed lower (P< 0.05 hen-day, and hen-housed egg production and feed conversion compared with rapid feathering Baladi pullets. Rapid feathering Leghorns had higher (P<0.05 adult body weight. age at sexual maturity, hen-day egg production, rate of mortality and feed intake and lower feed intake/kg eggs than rapid and slow feathering Baladi. However, rapid feathering Baladi and Leghorns had similar hen-housed egg production and feed intake per dozen eggs and had better (l’<0.05' performance than slow feathering Baladi.

Optical Aptamer Probes of Fluorescent Imaging to Rapid Monitoring of Circulating Tumor Cell

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Ji Yeon Hwang

2016-11-01

Full Text Available Fluorescence detecting of exogenous EpCAM (epithelial cell adhesion molecule or muc1 (mucin1 expression correlated to cancer metastasis using nanoparticles provides pivotal information on CTC (circulating tumor cell occurrence in a noninvasive tool. In this study, we study a new skill to detect extracellular EpCAM/muc1 using quantum dot-based aptamer beacon (QD-EpCAM/muc1 ALB (aptamer linker beacon. The QD-EpCAM/muc1 ALB was designed using QDs (quantum dots and probe. The EpCAM/muc1-targeting aptamer contains a Ep-CAM/muc1 binding sequence and BHQ1 (black hole quencher 1 or BHQ2 (black hole quencher2. In the absence of target EpCAM/muc1, the QD-EpCAM/muc1 ALB forms a partial duplex loop-like aptamer beacon and remained in quenched state because the BHQ1/2 quenches the fluorescence signal-on of the QD-EpCAM/muc1 ALB. The binding of EpCAM/muc1 of CTC to the EpCAM/muc1 binding aptamer sequence of the EpCAM/muc1-targeting oligonucleotide triggered the dissociation of the BHQ1/2 quencher and subsequent signal-on of a green/red fluorescence signal. Furthermore, acute inflammation was stimulated by trigger such as caerulein in vivo, which resulted in increased fluorescent signal of the cy5.5-EpCAM/muc1 ALB during cancer metastasis due to exogenous expression of EpCAM/muc1 in Panc02-implanted mouse model.

Rapid virtual hematoxylin and eosin histology of breast tissue specimens using a compact fluorescence nonlinear microscope.

Science.gov (United States)

Cahill, Lucas C; Giacomelli, Michael G; Yoshitake, Tadayuki; Vardeh, Hilde; Faulkner-Jones, Beverly E; Connolly, James L; Sun, Chi-Kuang; Fujimoto, James G

2018-01-01

Up to 40% of patients undergoing breast conserving surgery for breast cancer require repeat surgeries due to close to or positive margins. The lengthy processing required for evaluating surgical margins by standard paraffin-embedded histology precludes its use during surgery and therefore, technologies for rapid evaluation of surgical pathology could improve the treatment of breast cancer by reducing the number of surgeries required. We demonstrate real-time histological evaluation of breast cancer surgical specimens by staining specimens with acridine orange (AO) and sulforhodamine 101 (SR101) analogously to hematoxylin and eosin (H&E) and then imaging the specimens with fluorescence nonlinear microscopy (NLM) using a compact femtosecond fiber laser. A video-rate computational light absorption model was used to produce realistic virtual H&E images of tissue in real time and in three dimensions. NLM imaging could be performed to depths of 100 μm below the tissue surface, which is important since many surgical specimens require subsurface evaluation due to contamination artifacts on the tissue surface from electrocautery, surgical ink, or debris from specimen handling. We validate this method by expert review of NLM images compared to formalin-fixed, paraffin-embedded (FFPE) H&E histology. Diagnostically important features such as normal terminal ductal lobular units, fibrous and adipose stromal parenchyma, inflammation, invasive carcinoma, and in situ lobular and ductal carcinoma were present in NLM images associated with pathologies identified on standard FFPE H&E histology. We demonstrate that AO and SR101 were extracted to undetectable levels after FFPE processing and fluorescence in situ hybridization (FISH) HER2 amplification status was unaffected by the NLM imaging protocol. This method potentially enables cost-effective, real-time histological guidance of surgical resections.

Dynamic feedback circuits function as a switch for shaping a maturation-inducing steroid pulse in Drosophila

DEFF Research Database (Denmark)

Møller, Morten Erik; Danielsen, Erik Thomas; Herder, Rachel

2013-01-01

. Remarkably, our study shows that the same well-defined genetic program that stimulates a systemic downstream response to ecdysone is also utilized upstream to set the duration and amplitude of the ecdysone pulse. Activation of this switch-like mechanism ensures a rapid, self-limiting PG response......Steroid hormones trigger the onset of sexual maturation in animals by initiating genetic response programs that are determined by steroid pulse frequency, amplitude and duration. Although steroid pulses coordinate growth and timing of maturation during development, the mechanisms generating...... of hormone synthesis, the two key parameters determining pulse shape (amplitude and duration). We show that ecdysone has a positive-feedback effect on the PG, rapidly amplifying its own synthesis to trigger pupariation as the onset of maturation. During the prepupal stage, a negative-feedback signal ensures...

Rapid detection of Avian Influenza Virus - Towards point of care diagnosis

DEFF Research Database (Denmark)

Dhumpa, Raghuram

barcode and fluorescent beads were also developed for rapid detection and identification of the AIV. In both methods, the detection involved sandwiching of the target AIV between monoclonal antibodies for nucleoproteins and for matrix proteins. In the fluorescent DNA barcode-based immunoassay, fluorophore...

Plastic downregulation of the transcriptional repressor BCL6 during maturation of human dendritic cells

International Nuclear Information System (INIS)

Pantano, Serafino; Jarrossay, David; Saccani, Simona; Bosisio, Daniela; Natoli, Gioacchino

2006-01-01

Dendritic cell (DC) maturation links peripheral events initiated by the encounter with pathogens to the activation and expansion of antigen-specific T lymphocytes in secondary lymphoid organs. Here, we describe an as yet unrecognized modulator of human DC maturation, the transcriptional repressor BCL6. We found that both myeloid and plasmacytoid DCs constitutively express BCL6, which is rapidly downregulated following maturation triggered by selected stimuli. Both in unstimulated and maturing DCs, control of BCL6 protein levels reflects the convergence of several mechanisms regulating BCL6 stability, mRNA transcription and nuclear export. By regulating the induction of several genes implicated in the immune response, including inflammatory cytokines, chemokines and survival genes, BCL6 may represent a pivotal modulator of the afferent branch of the immune response

Emerging biomedical applications of time-resolved fluorescence spectroscopy

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Lakowicz, Joseph R.; Szmacinski, Henryk; Koen, Peter A.

1994-07-01

Time-resolved fluorescence spectroscopy is presently regarded as a research tool in biochemistry, biophysics, and chemical physics. Advances in laser technology, the development of long-wavelength probes, and the use of lifetime-based methods are resulting in the rapid migration of time-resolved fluorescence to the clinical chemistry lab, to the patient's bedside, to flow cytometers, to the doctor's office, and even to home health care. Additionally, time-resolved imaging is now a reality in fluorescence microscopy, and will provide chemical imaging of a variety of intracellular analytes and/or cellular phenomena. In this overview paper we attempt to describe some of the opportunities available using chemical sensing based on fluorescence lifetimes, and to predict those applications of lifetime-based sensing which are most likely in the near future.

Tolerance of a Knotted Near-Infrared Fluorescent Protein to Random Circular Permutation.

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Pandey, Naresh; Kuypers, Brianna E; Nassif, Barbara; Thomas, Emily E; Alnahhas, Razan N; Segatori, Laura; Silberg, Jonathan J

2016-07-12

Bacteriophytochrome photoreceptors (BphP) are knotted proteins that have been developed as near-infrared fluorescent protein (iRFP) reporters of gene expression. To explore how rearrangements in the peptides that interlace into the knot within the BphP photosensory core affect folding, we subjected iRFPs to random circular permutation using an improved transposase mutagenesis strategy and screened for variants that fluoresce. We identified 27 circularly permuted iRFPs that display biliverdin-dependent fluorescence in Escherichia coli. The variants with the brightest whole cell fluorescence initiated translation at residues near the domain linker and knot tails, although fluorescent variants that initiated translation within the PAS and GAF domains were discovered. Circularly permuted iRFPs retained sufficient cofactor affinity to fluoresce in tissue culture without the addition of biliverdin, and one variant displayed enhanced fluorescence when expressed in bacteria and tissue culture. This variant displayed a quantum yield similar to that of iRFPs but exhibited increased resistance to chemical denaturation, suggesting that the observed increase in the magnitude of the signal arose from more efficient protein maturation. These results show how the contact order of a knotted BphP can be altered without disrupting chromophore binding and fluorescence, an important step toward the creation of near-infrared biosensors with expanded chemical sensing functions for in vivo imaging.

Rapid quantification of polycyclic aromatic hydrocarbons in hydroxypropyl-{beta}-cyclodextrin (HPCD) soil extracts by synchronous fluorescence spectroscopy (SFS)

Energy Technology Data Exchange (ETDEWEB)

Guoxiong, Hua [School of Biology and Psychology, Institute for Research on Environment and Sustainability, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Broderick, John [School of Biology and Psychology, Institute for Research on Environment and Sustainability, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Semple, Kirk T [Department of Environmental Science, Faculty of Science and Technology, University of Lancaster, Lancaster LA1 4YQ (United Kingdom); Killham, Ken [School of Biological Sciences, University of Aberdeen, Aberdeen AB24 3UU (United Kingdom); Singleton, Ian [School of Biology and Psychology, Institute for Research on Environment and Sustainability, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

2007-07-15

Synchronous fluorescence spectroscopy (SFS) was directly applied to rapidly quantify selected polycyclic aromatic hydrocarbons (PAHs: benzo[a]pyrene and pyrene) in aqueous hydroxypropyl-{beta}-cyclodextrin (HPCD) soil extract solutions from a variety of aged contaminated soils containing four different PAHs. The method was optimized and validated. The results show that SFS can be used to analyse benzo[a]pyrene and pyrene in HPCD based soil extracts with high sensitivity and selectivity. The linear calibration ranges were 4.0 x 10{sup -6}-1.0 x 10{sup -3} mM for benzo[a]pyrene and 6.0 x 10{sup -6}-1.2 x 10{sup -3} mM for pyrene in 10 mM HPCD aqueous solution alone. The detection limits according to the error propagation theory for benzo[a]pyrene and pyrene were 3.9 x 10{sup -6} and 5.4 x 10{sup -6} mM, respectively. A good agreement between SFS and HPLC was reached for both determinations of PAHs in HPCD alone and in soil HPCD extracts. Hence, SFS is a potential means to simplify the present non-exhaustive hydroxypropyl-{beta}-cyclodextrin (HPCD)-based extraction technique for the evaluation of PAH bioavailability in soil. - SFS can be used to rapidly quantify selected PAHs in soil extracts and to simplify the non-exhaustive HPCD-based extraction technique for the evaluation of PAH bioavailability.

Rapid quantification of polycyclic aromatic hydrocarbons in hydroxypropyl-β-cyclodextrin (HPCD) soil extracts by synchronous fluorescence spectroscopy (SFS)

International Nuclear Information System (INIS)

Hua Guoxiong; Broderick, John; Semple, Kirk T.; Killham, Ken; Singleton, Ian

2007-01-01

Synchronous fluorescence spectroscopy (SFS) was directly applied to rapidly quantify selected polycyclic aromatic hydrocarbons (PAHs: benzo[a]pyrene and pyrene) in aqueous hydroxypropyl-β-cyclodextrin (HPCD) soil extract solutions from a variety of aged contaminated soils containing four different PAHs. The method was optimized and validated. The results show that SFS can be used to analyse benzo[a]pyrene and pyrene in HPCD based soil extracts with high sensitivity and selectivity. The linear calibration ranges were 4.0 x 10 -6 -1.0 x 10 -3 mM for benzo[a]pyrene and 6.0 x 10 -6 -1.2 x 10 -3 mM for pyrene in 10 mM HPCD aqueous solution alone. The detection limits according to the error propagation theory for benzo[a]pyrene and pyrene were 3.9 x 10 -6 and 5.4 x 10 -6 mM, respectively. A good agreement between SFS and HPLC was reached for both determinations of PAHs in HPCD alone and in soil HPCD extracts. Hence, SFS is a potential means to simplify the present non-exhaustive hydroxypropyl-β-cyclodextrin (HPCD)-based extraction technique for the evaluation of PAH bioavailability in soil. - SFS can be used to rapidly quantify selected PAHs in soil extracts and to simplify the non-exhaustive HPCD-based extraction technique for the evaluation of PAH bioavailability

In vitro differentiation and maturation of mouse embryonic stem cells into hepatocytes

International Nuclear Information System (INIS)

Ishii, Takamichi; Yasuchika, Kentaro; Fujii, Hideaki; Hoppo, Toshitaka; Baba, Shinji; Naito, Masato; Machimoto, Takafumi; Kamo, Naoko; Suemori, Hirofumi; Nakatsuji, Norio; Ikai, Iwao

2005-01-01

It is difficult to induce the maturation of embryonic stem (ES) cells into hepatocytes in vitro. We previously reported that Thy1-positive mesenchymal cells derived from the mouse fetal liver promote the maturation of hepatic progenitor cells. Here, we isolated alpha-fetoprotein (AFP)-producing cells from mouse ES cells for subsequent differentiation into hepatocytes in vitro by coculture with Thy1-positive cells. ES cells expressing green fluorescent protein (GFP) under the control of an AFP promoter were cultured under serum- and feeder layer-free culture conditions. The proportion of GFP-positive cells plateaued at 41.6 ± 12.2% (means ± SD) by day 7. GFP-positive cells, isolated by flow cytometry, were cultured in the presence or absence of Thy1-positive cells as a feeder layer. Isolated GFP-positive cells were stained for AFP, Foxa2, and albumin. The expression of mRNAs encoding tyrosine amino transferase, tryptophan 2,3-dioxygenase, and glucose-6-phosphatase were only detected following coculture with Thy1-positive cells. Following coculture with Thy1-positive cells, the isolated cells produced and stored glycogen. Ammonia clearance activity was also enhanced following coculture. Electron microscopic analysis indicated that the cocultured cells exhibited the morphologic features of mature hepatocytes. In conclusion, coculture with Thy1-positive cells in vitro induced the maturation of AFP-producing cells isolated from ES cell cultures into hepatocytes

Rapid analysis and exploration of fluorescence microscopy images.

Science.gov (United States)

Pavie, Benjamin; Rajaram, Satwik; Ouyang, Austin; Altschuler, Jason M; Steininger, Robert J; Wu, Lani F; Altschuler, Steven J

2014-03-19

Despite rapid advances in high-throughput microscopy, quantitative image-based assays still pose significant challenges. While a variety of specialized image analysis tools are available, most traditional image-analysis-based workflows have steep learning curves (for fine tuning of analysis parameters) and result in long turnaround times between imaging and analysis. In particular, cell segmentation, the process of identifying individual cells in an image, is a major bottleneck in this regard. Here we present an alternate, cell-segmentation-free workflow based on PhenoRipper, an open-source software platform designed for the rapid analysis and exploration of microscopy images. The pipeline presented here is optimized for immunofluorescence microscopy images of cell cultures and requires minimal user intervention. Within half an hour, PhenoRipper can analyze data from a typical 96-well experiment and generate image profiles. Users can then visually explore their data, perform quality control on their experiment, ensure response to perturbations and check reproducibility of replicates. This facilitates a rapid feedback cycle between analysis and experiment, which is crucial during assay optimization. This protocol is useful not just as a first pass analysis for quality control, but also may be used as an end-to-end solution, especially for screening. The workflow described here scales to large data sets such as those generated by high-throughput screens, and has been shown to group experimental conditions by phenotype accurately over a wide range of biological systems. The PhenoBrowser interface provides an intuitive framework to explore the phenotypic space and relate image properties to biological annotations. Taken together, the protocol described here will lower the barriers to adopting quantitative analysis of image based screens.

Wolbachia infect ovaries in the course of their maturation: last minute passengers and priority travellers?

Directory of Open Access Journals (Sweden)

Lise-Marie Genty

Full Text Available Wolbachia are widespread endosymbiotic bacteria of arthropods and nematodes. Studies on such models suggest that Wolbachia's remarkable aptitude to infect offspring may rely on a re-infection of ovaries from somatic tissues instead of direct cellular segregation between oogonia and oocytes. In the terrestrial isopod Armadillidium vulgare, Wolbachia are vertically transmitted to the host offspring, even though ovary cells are cyclically renewed. Using Fluorescence in situ hybridization (FISH, we showed that the proportion of infected oocytes increased in the course of ovary and oocyte maturation, starting with 31.5% of infected oocytes only. At the end of ovary maturation, this proportion reached 87.6% for the most mature oocytes, which is close to the known transmission rate to offspring. This enrichment can be explained by a secondary acquisition of the bacteria by oocytes (Wolbachia can be seen as last minute passengers and/or by a preferential selection of oocytes infected with Wolbachia (as priority travellers.

Highly selective and rapidly responsive fluorescent probe for hydrogen sulfide detection in wine.

Science.gov (United States)

Wang, Hao; Wang, Jialin; Yang, Shaoxiang; Tian, Hongyu; Liu, Yongguo; Sun, Baoguo

2018-08-15

A new fluorescent probe 6-(2, 4-dinitrophenoxy)-2-naphthonitrile (probe 1) was designed and synthesized for the selective detection of hydrogen sulfide (H 2 S). The addition of H 2 S to a solution of probe 1 resulted in a marked fluorescence turn-on alongside a visual color change from colorless to light yellow. Importantly, this distinct color response indicated that probe 1 could be used as a visual sensor for H 2 S. Moreover, probe 1 was successfully used as a signal tool to determine the H 2 S levels in beer and red wine. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparative Studies on Bioactive Constituents in Hawk Tea Infusions with Different Maturity Degree and Their Antioxidant Activities

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Ming Yuan

2014-01-01

Full Text Available Hawk tea (Litsea coreana var. lanuginose is a very popular herbal tea in the southwest of China. According to the maturity degree of raw materials, Hawk tea can usually be divided into three types: Hawk bud tea (HB, Hawk primary leaf tea (HP, and Hawk mature leaf tea (HM. In this study, some of the bioactive constituents and antioxidant properties of the three kinds of Hawk tea infusions were comparatively investigated. The results showed that the contents of total flavonoids, vitamin C, and carbohydrates in Hawk bud tea infusion (HBI were higher than those in Hawk primary leaf tea infusion (HPI and Hawk mature leaf tea infusion (HMI. HPI had higher contents of total polyphenols and exhibited better DPPH radical scavenging activity and ferric reducing activity power. HBI could provide more effective protection against erythrocyte hemolysis. As age is going from bud to mature leaf, the ability to inhibit the formation of low density lipoprotein (LDL conjugated diene and the loss of tryptophan fluorescence decreased. The bioactive constituents and antioxidant activities of Hawk tea infusions were significantly affected by the maturity degree of the raw material.

Fluorescence In Situ Hybridization (FISH-Based Karyotyping Reveals Rapid Evolution of Centromeric and Subtelomeric Repeats in Common Bean (Phaseolus vulgaris and Relatives

Directory of Open Access Journals (Sweden)

Aiko Iwata-Otsubo

2016-04-01

Full Text Available Fluorescence in situ hybridization (FISH-based karyotyping is a powerful cytogenetics tool to study chromosome organization, behavior, and chromosome evolution. Here, we developed a FISH-based karyotyping system using a probe mixture comprised of centromeric and subtelomeric satellite repeats, 5S rDNA, and chromosome-specific BAC clones in common bean, which enables one to unambiguously distinguish all 11 chromosome pairs. Furthermore, we applied the karyotyping system to several wild relatives and landraces of common bean from two distinct gene pools, as well as other related Phaseolus species, to investigate repeat evolution in the genus Phaseolus. Comparison of karyotype maps within common bean indicates that chromosomal distribution of the centromeric and subtelomeric satellite repeats is stable, whereas the copy number of the repeats was variable, indicating rapid amplification/reduction of the repeats in specific genomic regions. In Phaseolus species that diverged approximately 2–4 million yr ago, copy numbers of centromeric repeats were largely reduced or diverged, and chromosomal distributions have changed, suggesting rapid evolution of centromeric repeats. We also detected variation in the distribution pattern of subtelomeric repeats in Phaseolus species. The FISH-based karyotyping system revealed that satellite repeats are actively and rapidly evolving, forming genomic features unique to individual common bean accessions and Phaseolus species.

Reticulocyte maturity indices in iron deficiency anemia

Directory of Open Access Journals (Sweden)

Muriel Wollmann

2014-01-01

Full Text Available Objective: The aim of this study was to analyze the reticulocyte maturity indices (low, medium, and high fluorescence ratios in iron deficient 1- to 6-year-old children, and identify the prevalence of iron deficiency anemia in this population. Methods: The present study included 39 subjects, divided into two groups: control subjects (n = 33, and subjects with iron deficiency anemia (n = 6. The results were analyzed by Student's t-test for comparison of means. Differences were considered significant when two-tailed p-value < 0.05. Results: Subjects with iron deficiency anemia presented increases in the proportion of mean (10.3 ± 4.7% vs. 6.0 ± 3.4%; p-value = 0.003, and high fluorescence reticulocytes (2.3 ± 0.87% vs. 0.9 ± 0.9%; p-value = 0.03 compared to the control group. The prevalence of anemia in this population was 15% (n = 6. Conclusion: The indices related to immaturity of reticulocytes are higher in the presence of iron deficiency, thus demonstrating a deficiency in the raw material to form hemoglobin and are, therefore, possible early markers of iron deficiency and anemia. We emphasize the need to standardize these indices for use in clinical practice and lab test results.

[Rapid determination of major and trace elements in the salt lake clay minerals by X-ray fluorescence spectrometry].

Science.gov (United States)

Wang, Xiao-Huan; Meng, Qing-Fen; Dong, Ya-Ping; Chen, Mei-Da; Li, Wu

2010-03-01

A rapid multi-element analysis method for clay mineral samples was described. This method utilized a polarized wave-length dispersive X-ray fluorescence spectrometer--Axios PW4400, which had a maximum tube power of 4 000 watts. The method was developed for the determination of As, Mn, Co, Cu, Cr, Dy, Ga, Mo, P, Pb, Rb, S, Sr, Ni, ,Cs, Ta, Th, Ti, U, V, Y, Zn, Zr, MgO, K2O, Na2O, CaO, Fe2O3, Al2O3, SiO2 and so on. Thirty elements in clay mineral species were measured by X-ray fluorescence spectrometry with pressed powder pellets. Spectral interferences, in particular the indirect interferences of each element, were studied. A method to distinguish the interference between each other periodic elements in element periodic table was put forward. The measuring conditions and existence were mainly investigated, and the selected background position as well as corrected spectral overlap for the trace elements were also discussed. It was found that the indirect spectral overlap line was the same important as direct spectral overlap line. Due to inducing the effect of indirect spectral overlap, some elements jlike Bi, Sn, W which do not need analysis were also added to the elements channel. The relative standard deviation (RSD) was in the range of 0.01% to 5.45% except three elements Mo, Cs and Ta. The detection limits, precisions and accuracies for most elements using this method can meet the requirements of sample analysis in clay mineral species.

Site-specific fluorescent labeling of nascent proteins on the translating ribosome.

Science.gov (United States)

Saraogi, Ishu; Zhang, Dawei; Chandrasekaran, Sandhya; Shan, Shu-ou

2011-09-28

As newly synthesized proteins emerge from the ribosome, they interact with a variety of cotranslational cellular machineries that facilitate their proper folding, maturation, and localization. These interactions are essential for proper function of the cell, and the ability to study these events is crucial to understanding cellular protein biogenesis. To this end, we have developed a highly efficient method to generate ribosome-nascent chain complexes (RNCs) site-specifically labeled with a fluorescent dye on the nascent polypeptide. The fluorescent RNC provides real-time, quantitative information on its cotranslational interaction with the signal recognition particle and will be a valuable tool in elucidating the role of the translating ribosome in numerous biochemical pathways.

Relative Skeletal Maturation and Population Ancestry in Nonobese Children and Adolescents.

Science.gov (United States)

McCormack, Shana E; Chesi, Alessandra; Mitchell, Jonathan A; Roy, Sani M; Cousminer, Diana L; Kalkwarf, Heidi J; Lappe, Joan M; Gilsanz, Vicente; Oberfield, Sharon E; Shepherd, John A; Mahboubi, Soroosh; Winer, Karen K; Kelly, Andrea; Grant, Struan Fa; Zemel, Babette S

2017-01-01

More rapid skeletal maturation in African-American (AA) children is recognized and generally attributed to an increased prevalence of obesity. The objective of the present study was to evaluate the effects of population ancestry on relative skeletal maturation in healthy, non-obese children and adolescents, accounting for body composition and sexual maturation. To do this, we leveraged a multiethnic, mixed-longitudinal study with annual assessments for up to 7 years (The Bone Mineral Density in Childhood Study and its ancillary cohort) conducted at five US clinical centers. Participants included 1592 children, skeletally immature (45% females, 19% AA) who were aged 5 to 17 years at study entry. The primary outcome measure was relative skeletal maturation as assessed by hand-wrist radiograph. Additional covariates measured included anthropometrics, body composition by dual-energy X-ray absorptiometry (DXA), and Tanner stage of sexual maturation. Using mixed effects longitudinal models, without covariates, advancement in relative skeletal maturation was noted in self-reported AA girls (∼0.33 years, p ancestry groups showed independent positive associations of height, lean mass, fat mass, and puberty with relative skeletal maturation. The effect of ancestry was attenuated but persistent after accounting for covariates: for girls, 0.19 years (ancestry by self-report, p = 0.02) or 0.29 years (ancestry by admixture, p = 0.004); and for boys, 0.20 years (ancestry by self-report, p = 0.004), or 0.29 years (ancestry by admixture, p = 0.004). In summary, we conclude that advancement in relative skeletal maturation was associated with AA ancestry in healthy, non-obese children, independent of growth, body composition, and puberty. Further research into the mechanisms underlying this observation may provide insights into the regulation of skeletal maturation. © 2016 American Society for Bone and Mineral Research. © 2016 American Society for Bone and

Multispectral fluorescence imaging techniques for nondestructive food safety inspection

Science.gov (United States)

Kim, Moon S.; Lefcourt, Alan M.; Chen, Yud-Ren

2004-03-01

The use of spectral sensing has gained acceptance as a rapid means for nondestructive inspection of postharvest food produce. Current technologies generally use color or a single wavelength camera technology. The applicability and sensitivity of these techniques can be expanded through the use of multiple wavelengths. Reflectance in the Vis/NIR is the prevalent spectral technique. Fluorescence, compared to reflectance, is regarded as a more sensitive technique due to its dynamic responses to subtle changes in biological entities. Our laboratory has been exploring fluorescence as a potential means for detection of quality and wholesomeness of food products. Applications of fluorescence sensing require an understanding of the spectral characteristics emanating from constituents and potential contaminants. A number of factors affecting fluorescence emission characteristics are discussed. Because of relatively low fluorescence quantum yield from biological samples, a system with a powerful pulse light source such as a laser coupled with a gated detection device is used to harvest fluorescence, in the presence of ambient light. Several fluorescence sensor platforms developed in our laboratory, including hyperspectral imaging, and laser-induced fluorescence (LIF) and steady-state fluorescence imaging systems with multispectral capabilities are presented. We demonstrate the potential uses of recently developed fluorescence imaging platforms in food safety inspection of apples contaminated with animal feces.

The use of fluorescence microscopy and image analysis for rapid detection of non-producing revertant cells of Synechocystis sp. PCC6803 and Synechococcus sp. PCC7002.

Science.gov (United States)

Schulze, Katja; Lang, Imke; Enke, Heike; Grohme, Diana; Frohme, Marcus

2015-04-17

Ethanol production via genetically engineered cyanobacteria is a promising solution for the production of biofuels. Through the introduction of a pyruvate decarboxylase and alcohol dehydrogenase direct ethanol production becomes possible within the cells. However, during cultivation genetic instability can lead to mutations and thus loss of ethanol production. Cells then revert back to the wild type phenotype. A method for a rapid and simple detection of these non-producing revertant cells in an ethanol producing cell population is an important quality control measure in order to predict genetic stability and the longevity of a producing culture. Several comparable cultivation experiments revealed a difference in the pigmentation for non-producing and producing cells: the accessory pigment phycocyanin (PC) is reduced in case of the ethanol producer, resulting in a yellowish appearance of the culture. Microarray and western blot studies of Synechocystis sp. PCC6803 and Synechococcus sp. PCC7002 confirmed this PC reduction on the level of RNA and protein. Based on these findings we developed a method for fluorescence microscopy in order to distinguish producing and non-producing cells with respect to their pigmentation phenotype. By applying a specific filter set the emitted fluorescence of a producer cell with a reduced PC content appeared orange. The emitted fluorescence of a non-producing cell with a wt pigmentation phenotype was detected in red, and dead cells in green. In an automated process multiple images of each sample were taken and analyzed with a plugin for the image analysis software ImageJ to identify dead (green), non-producing (red) and producing (orange) cells. The results of the presented validation experiments revealed a good identification with 98 % red cells in the wt sample and 90 % orange cells in the producer sample. The detected wt pigmentation phenotype (red cells) in the producer sample were either not fully induced yet (in 48 h induced

A rapid and universal bacteria-counting approach using CdSe/ZnS/SiO2 composite nanoparticles as fluorescence probe.

Science.gov (United States)

Fu, Xin; Huang, Kelong; Liu, Suqin

2010-02-01

In this paper, a rapid, simple, and sensitive method was described for detection of the total bacterial count using SiO(2)-coated CdSe/ZnS quantum dots (QDs) as a fluorescence marker that covalently coupled with bacteria using glutaraldehyde as the crosslinker. Highly luminescent CdSe/ZnS were prepared by applying cadmium oxide and zinc stearate as precursors instead of pyrophoric organometallic precursors. A reverse-microemulsion technique was used to synthesize CdSe/ZnS/SiO(2) composite nanoparticles with a SiO(2) surface coating. Our results showed that CdSe/ZnS/SiO(2) composite nanoparticles prepared with this method possessed highly luminescent, biologically functional, and monodispersive characteristics, and could successfully be covalently conjugated with the bacteria. As a demonstration, it was found that the method had higher sensitivity and could count bacteria in 3 x 10(2) CFU/mL, lower than the conventional plate counting and organic dye-based method. A linear relationship of the fluorescence peak intensity (Y) and the total bacterial count (X) was established in the range of 3 x 10(2)-10(7) CFU/mL using the equation Y = 374.82X-938.27 (R = 0.99574). The results of the determination for the total count of bacteria in seven real samples were identical with the conventional plate count method, and the standard deviation was satisfactory.

Protein subcellular localization assays using split fluorescent proteins

Science.gov (United States)

Waldo, Geoffrey S [Santa Fe, NM; Cabantous, Stephanie [Los Alamos, NM

2009-09-08

The invention provides protein subcellular localization assays using split fluorescent protein systems. The assays are conducted in living cells, do not require fixation and washing steps inherent in existing immunostaining and related techniques, and permit rapid, non-invasive, direct visualization of protein localization in living cells. The split fluorescent protein systems used in the practice of the invention generally comprise two or more self-complementing fragments of a fluorescent protein, such as GFP, wherein one or more of the fragments correspond to one or more beta-strand microdomains and are used to "tag" proteins of interest, and a complementary "assay" fragment of the fluorescent protein. Either or both of the fragments may be functionalized with a subcellular targeting sequence enabling it to be expressed in or directed to a particular subcellular compartment (i.e., the nucleus).

Utilização de fluorescência de clorofila na separação de sementes esverdeadas de soja

OpenAIRE

CICERO, Silvio Moure; SCHOOR, Rob Van Der; JALINK, Henk

2009-01-01

The occurrence of green seeded soybeans [Glycine max (L.) Merrill] is a problem closely related to unfavorable climatic conditions, mainly drought, that occurs during the final stages of seed maturation. This problem causes serious losses to soybean seed quality in Brazil. In these seeds, chlorophyll is not properly degraded during maturation, drastically reducing seed quality. Using the chlorophyll fluorescence technique, it is possible to remove green seeds from the seed lot, improving seed...

Rapid creation of distant entanglement by multi-photon resonant fluorescence

Science.gov (United States)

Cohen, Guy Z.; Sham, L. J.

2014-03-01

We study a simple, effective and robust method for entangling two separate stationary quantum dot spin qubits with high fidelity using multi-photon Gaussian state. The fluorescence signals from the two dots interfere at a beam splitter. The bosonic nature of photons leads, in analogy with the Hong-Ou-Mandel (HOM) effect, to selective pairing of photon holes (photon absences in the fluorescent signals). By the HOM effect, two photon holes with the same polarization end up at the same beam splitter output. As a result, two odd photon number detections at the outgoing beams, which must correspond to two photon holes with different polarizations, herald entanglement creation. The robustness of the Gaussian states is evidenced by the ability to compensate for photon absorption and noise by a moderate increase in the number of photons at the input. We calculate the entanglement generation rate in the ideal, non-ideal and near-ideal detector regimes and find substantial improvement over single-photon schemes in all three regimes. Fast and efficient spin-spin entanglement creation can form the basis for a scalable quantum dot quantum computing network. Our predictions can be tested using current experimental capabilities. This research was supported by the U.S. Army Research Office MURI award W911NF0910406, by NSF grant PHY-1104446 and by ARO (IARPA, W911NF-08-1-0487). The authors thank D. G. Steel for useful discussions.

Fluorescence-based rapid measurement of sphingosine-1-phosphate transport activity in erythrocytes[S

Science.gov (United States)

Kobayashi, Naoki; Otsuka, Masato; Yamaguchi, Akihito; Nishi, Tsuyoshi

2016-01-01

Sphingosine-1-phosphate (S1P) is present in the blood plasma and acts as a pivotal intercellular signal transmitter in the immune system by recruiting lymphocytes from the thymus and secondary lymphoid tissues. The plasma S1P concentration is maintained by the supply of S1P from erythrocytes. Previously, we showed that S1P release from erythrocytes is mediated by an ATP-dependent transporter. In this study, we attempted to establish a rapid and reliable method for measuring the S1P transport activity in erythrocytes by using a fluorescent S1P analog, 7-nitro-2-1,3-benzoxadiazol-4-yl (NBD)-labeled S1P. NBD-S1P was released from erythrocytes in a time-dependent manner. The NBD-S1P release was reduced after exposure to glyburide, which is an inhibitor of the S1P transporter in erythrocytes. Moreover, the release of NBD-S1P and S1P from erythrocytes was competitively inhibited by intracellular S1P and NBD-S1P, respectively. These results showed that the erythrocyte S1P transporter exports NBD-S1P. We optimized the sample-preparation conditions and lipid extraction to increase the sensitivity of the assay. Furthermore, we successfully measured NBD-S1P release without lipid extraction by decreasing the concentration of BSA in the assay buffer to 0.1%. This method will be useful for the high-throughput screening of S1P transporter inhibitors using conventional fluorometers. PMID:27655910

Rapid algal toxicity assay using variable chlorophyll fluorescence for Chlorella kessleri (Chlorophyta)

Czech Academy of Sciences Publication Activity Database

Kvíderová, Jana

2010-01-01

Roč. 25, č. 6 (2010), s. 554-562 ISSN 1520-4081 R&D Projects: GA MŠk 1M0571 Institutional research plan: CEZ:AV0Z60050516 Keywords : bioassay * variable chlorophyll fluorescence * Chlorella kessleri Subject RIV: EF - Botanics Impact factor: 1.932, year: 2010

Evaluation of a rapid immunodiagnostic test kit for rabies virus.

Science.gov (United States)

Kang, BoKyu; Oh, JinSik; Lee, ChulSeung; Park, Bong-Kyun; Park, YoungNam; Hong, KyungSoo; Lee, KyungGi; Cho, ByungKi; Song, DaeSub

2007-10-01

A rapid immunodiagnostic test kit for rabies virus detection was evaluated using 51 clinical samples and 4 isolates of rabies virus. The quick detection of rabies virus under field conditions may be helpful in determining if post-exposure prophylaxis is needed, thereby avoiding unnecessary treatments, as well as undue economic burden. There are several widely used diagnostic methods for rabies, including fluorescent antibody tests, reverse transcription polymerase chain reaction, and electron microscopy; however, these methods include time-consuming, intricate, and costly procedures. The rapid immunodiagnostic test was able to detect rabies virus in clinical samples, including brain tissue and saliva, in addition to 10(3.2) 50% lethal dose (LD(50))/mL cell-adapted rabies virus. The assay was not cross-reactive with non-rabies virus microbes. When the performance of the rapid immunodiagnostic test was compared to a fluorescent antibody test, the rapid immunodiagnostic test had a sensitivity of 91.7% and specificity of 100% (95.8% CI).

Maturation of Rapid Auditory Temporal Processing and Subsequent Nonword Repetition Performance in Children

Science.gov (United States)

Fox, Allison M.; Reid, Corinne L.; Anderson, Mike; Richardson, Cassandra; Bishop, Dorothy V. M.

2012-01-01

According to the rapid auditory processing theory, the ability to parse incoming auditory information underpins learning of oral and written language. There is wide variation in this low-level perceptual ability, which appears to follow a protracted developmental course. We studied the development of rapid auditory processing using event-related…

A green fluorescent protein with photoswitchable emission from the deep sea.

Directory of Open Access Journals (Sweden)

Alexander Vogt

Full Text Available A colorful variety of fluorescent proteins (FPs from marine invertebrates are utilized as genetically encoded markers for live cell imaging. The increased demand for advanced imaging techniques drives a continuous search for FPs with new and improved properties. Many useful FPs have been isolated from species adapted to sun-flooded habitats such as tropical coral reefs. It has yet remained unknown if species expressing green fluorescent protein (GFP-like proteins also exist in the darkness of the deep sea. Using a submarine-based and -operated fluorescence detection system in the Gulf of Mexico, we discovered ceriantharians emitting bright green fluorescence in depths between 500 and 600 m and identified a GFP, named cerFP505, with bright fluorescence emission peaking at 505 nm. Spectroscopic studies showed that approximately 15% of the protein bulk feature reversible ON/OFF photoswitching that can be induced by alternating irradiation with blue und near-UV light. Despite being derived from an animal adapted to essentially complete darkness and low temperatures, cerFP505 maturation in living mammalian cells at 37 degrees C, its brightness and photostability are comparable to those of EGFP and cmFP512 from shallow water species. Therefore, our findings disclose the deep sea as a potential source of GFP-like molecular marker proteins.

Measurement of cell volume changes by fluorescence self-quenching

DEFF Research Database (Denmark)

Hamann, Steffen; Kiilgaard, J.F.; Litman, Thomas

2002-01-01

At high concentrations, certain fluorophores undergo self-quenching, i.e., fluorescence intensity decreases with increasing fluorophore concentration. Accordingly, the self-quenching properties can be used for measuring water volume changes in lipid vesicles. In cells, quantitative determination...... concentrations of the fluorophore calcein suitable for measurement of changes in cell water volume by self-quenching. The relationship between calcein fluorescence intensity, when excited at 490 nm (its excitation maximum), and calcein concentration was investigated in vitro and in various cultured cell types...... to a decrease in calcein fluorescence with high signal-to-noise ratio (>15). Similar results were obtained with the fluorophore BCECF when excited at its isosbestic wavelength (436 nm). The present results demonstrate the usefulness of fluorescence self-quenching to measure rapid changes in cell water volume....

Enhancement of early cervical cancer diagnosis with epithelial layer analysis of fluorescence lifetime images.

Directory of Open Access Journals (Sweden)

Jun Gu

Full Text Available This work reports the use of layer analysis to aid the fluorescence lifetime diagnosis of cervical intraepithelial neoplasia (CIN from H&E stained cervical tissue sections. The mean and standard deviation of lifetimes in single region of interest (ROI of cervical epithelium were previously shown to correlate to the gold standard histopathological classification of early cervical cancer. These previously defined single ROIs were evenly divided into layers for analysis. A 10-layer model revealed a steady increase in fluorescence lifetime from the inner to the outer epithelial layers of healthy tissue sections, suggesting a close association with cellular maturity. The shorter lifetime and minimal lifetime increase towards the epithelial surface of CIN-affected regions are in good agreement with the absence of cellular maturation in CIN. Mean layer lifetimes in the top-half cervical epithelium were used as feature vectors for extreme learning machine (ELM classifier discriminations. It was found that the proposed layer analysis technique greatly improves the sensitivity and specificity to 94.6% and 84.3%, respectively, which can better supplement the traditional gold standard cervical histopathological examinations.

[Molecular beacon based PNA-FISH method combined with fluorescence scanning for rapid detection of Listeria monocytogenes].

Science.gov (United States)

Wu, Shan; Zhang, Xiaofeng; Shuai, Jiangbing; Li, Ke; Yu, Huizhen; Jin, Chenchen

2016-07-04

To simplify the PNA-FISH (Peptide nucleic acid-fluorescence in situ hybridization) test, molecular beacon based PNA probe combined with fluorescence scanning detection technology was applied to replace the original microscope observation to detect Listeria monocytogenes The 5′ end and 3′ end of the L. monocytogenes specific PNA probes were labeled with the fluorescent group and the quenching group respectively, to form a molecular beacon based PNA probe. When PNA probe used for fluorescence scanning and N1 treatment as the control, the false positive rate was 11.4%, and the false negative rate was 0; when N2 treatment as the control, the false positive rate decreased to 4.3%, but the false negative rate rose to 18.6%. When beacon based PNA probe used for fluorescence scanning, taken N1 treatment as blank control, the false positive rate was 8.6%, and the false negative rate was 1.4%; taken N2 treatment as blank control, the false positive rate was 5.7%, and the false negative rate was 1.4%. Compared with PNA probe, molecular beacon based PNA probe can effectively reduce false positives and false negatives. The success rates of hybridization of the two PNA probes were 83.3% and 95.2% respectively; and the rates of the two beacon based PNA probes were 91.7% and 90.5% respectively, which indicated that labeling the both ends of the PNA probe dose not decrease the hybridization rate with the target bacteria. The combination of liquid phase PNA-FISH and fluorescence scanning method, can significantly improve the detection efficiency.

Teaching laser-induced fluorescence of plant leaves

Science.gov (United States)

Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

2016-11-01

Plants convert carbon dioxide into sugars using the energy of sunlight. Absorbed light unused for conversion is dissipated primarily as heat with a small fraction re-emitted as fluorescence at longer wavelengths. One can use the latter to estimate photosynthetic activity. The illumination of intact leaves with strong light after keeping them in dark for tens of minutes results in a rapid increase followed by a slow decay of fluorescence emission from the fluorophore chlorophyll-a, called the Kautsky effect. This paper describes a laboratory practice that introduces students of physics or engineering into this research field. It begins with the spectral measurement of the fluorescence emitted by a plant leaf upon UV excitation. Then it focuses on the red and far-red components of the fluorescence emission spectrum characteristic to the chlorophyll-a molecule and presents an inexpensive demonstration of the Kautsky effect. As researchers use more complex measurement techniques and tools, the practice ends up with the demonstration of an intelligent fluorosensor, a compact tool developed for plant physiological research and horticulture applications together with a brief interpretation of some important fluorescence parameters.

Teaching laser-induced fluorescence of plant leaves

International Nuclear Information System (INIS)

Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

2016-01-01

Plants convert carbon dioxide into sugars using the energy of sunlight. Absorbed light unused for conversion is dissipated primarily as heat with a small fraction re-emitted as fluorescence at longer wavelengths. One can use the latter to estimate photosynthetic activity. The illumination of intact leaves with strong light after keeping them in dark for tens of minutes results in a rapid increase followed by a slow decay of fluorescence emission from the fluorophore chlorophyll -a , called the Kautsky effect. This paper describes a laboratory practice that introduces students of physics or engineering into this research field. It begins with the spectral measurement of the fluorescence emitted by a plant leaf upon UV excitation. Then it focuses on the red and far-red components of the fluorescence emission spectrum characteristic to the chlorophyll -a molecule and presents an inexpensive demonstration of the Kautsky effect. As researchers use more complex measurement techniques and tools, the practice ends up with the demonstration of an intelligent fluorosensor, a compact tool developed for plant physiological research and horticulture applications together with a brief interpretation of some important fluorescence parameters. (paper)

Non-Destructive Optical Monitoring of Grape Maturation by Proximal Sensing

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Gwendal Latouche

2010-11-01

Full Text Available A new, commercial, fluorescence-based optical sensor for plant constituent assessment was recently introduced. This sensor, called the Multiplex® (FORCE-A, Orsay, France, was used to monitor grape maturation by specifically monitoring anthocyanin accumulation. We derived the empirical anthocyanin content calibration curves for Champagne red grape cultivars, and we also propose a general model for the influence of the proportion of red berries, skin anthocyanin content and berry size on Multiplex® indices. The Multiplex® was used on both berry samples in the laboratory and on intact clusters in the vineyard. We found that the inverted and log-transformed far-red fluorescence signal called the FERARI index, although sensitive to sample size and distance, is potentially the most widely applicable. The more robust indices, based on chlorophyll fluorescence excitation ratios, showed three ranges of dependence on anthocyanin content. We found that up to 0.16 mg cm−2, equivalent to approximately 0.6 mg g−1, all indices increase with accumulation of skin anthocyanin content. Excitation ratio-based indices decrease with anthocyanin accumulation beyond 0.27 mg cm−2. We showed that the Multiplex® can be advantageously used in vineyards on intact clusters for the non-destructive assessment of anthocyanin content of vine blocks and can now be tested on other fruits and vegetables based on the same model.

Non-Destructive Optical Monitoring of Grape Maturation by Proximal Sensing

Science.gov (United States)

Ben Ghozlen, Naïma; Cerovic, Zoran G.; Germain, Claire; Toutain, Sandrine; Latouche, Gwendal

2010-01-01

A new, commercial, fluorescence-based optical sensor for plant constituent assessment was recently introduced. This sensor, called the Multiplex® (FORCE-A, Orsay, France), was used to monitor grape maturation by specifically monitoring anthocyanin accumulation. We derived the empirical anthocyanin content calibration curves for Champagne red grape cultivars, and we also propose a general model for the influence of the proportion of red berries, skin anthocyanin content and berry size on Multiplex® indices. The Multiplex® was used on both berry samples in the laboratory and on intact clusters in the vineyard. We found that the inverted and log-transformed far-red fluorescence signal called the FERARI index, although sensitive to sample size and distance, is potentially the most widely applicable. The more robust indices, based on chlorophyll fluorescence excitation ratios, showed three ranges of dependence on anthocyanin content. We found that up to 0.16 mg cm−2, equivalent to approximately 0.6 mg g−1, all indices increase with accumulation of skin anthocyanin content. Excitation ratio-based indices decrease with anthocyanin accumulation beyond 0.27 mg cm−2. We showed that the Multiplex® can be advantageously used in vineyards on intact clusters for the non-destructive assessment of anthocyanin content of vine blocks and can now be tested on other fruits and vegetables based on the same model. PMID:22163456

In vitro evolution and affinity-maturation with Coliphage qβ display.

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Claudia Skamel

Full Text Available The Escherichia coli bacteriophage, Qβ (Coliphage Qβ, offers a favorable alternative to M13 for in vitro evolution of displayed peptides and proteins due to high mutagenesis rates in Qβ RNA replication that better simulate the affinity maturation processes of the immune response. We describe a benchtop in vitro evolution system using Qβ display of the VP1 G-H loop peptide of foot-and-mouth disease virus (FMDV. DNA encoding the G-H loop was fused to the A1 minor coat protein of Qβ resulting in a replication-competent hybrid phage that efficiently displayed the FMDV peptide. The surface-localized FMDV VP1 G-H loop cross-reacted with the anti-FMDV monoclonal antibody (mAb SD6 and was found to decorate the corners of the Qβ icosahedral shell by electron microscopy. Evolution of Qβ-displayed peptides, starting from fully degenerate coding sequences corresponding to the immunodominant region of VP1, allowed rapid in vitro affinity maturation to SD6 mAb. Qβ selected under evolutionary pressure revealed a non-canonical, but essential epitope for mAb SD6 recognition consisting of an Arg-Gly tandem pair. Finally, the selected hybrid phages induced polyclonal antibodies in guinea pigs with good affinity to both FMDV and hybrid Qβ-G-H loop, validating the requirement of the tandem pair epitope. Qβ-display emerges as a novel framework for rapid in vitro evolution with affinity-maturation to molecular targets.

Rapid Analysis and Exploration of Fluorescence Microscopy Images

OpenAIRE

Pavie, Benjamin; Rajaram, Satwik; Ouyang, Austin; Altschuler, Jason; Steininger, Robert J; Wu, Lani; Altschuler, Steven

2014-01-01

Despite rapid advances in high-throughput microscopy, quantitative image-based assays still pose significant challenges. While a variety of specialized image analysis tools are available, most traditional image-analysis-based workflows have steep learning curves (for fine tuning of analysis parameters) and result in long turnaround times between imaging and analysis. In particular, cell segmentation, the process of identifying individual cells in an image, is a major bottleneck in this regard.

Mechanism of Na,K-ATPase decline during sheep red cell maturation

International Nuclear Information System (INIS)

Grafova, E.; Blostein, R.

1987-01-01

Na,K-ATPase of immature and mature sheep red cells of both the high-K + and low-K + genotypes as well as cells of both types matured in vitro was detected using polyclonal antiserum to sheep kidney Na,K-ATPase. Following SDS-PAGE and immunoblotting, the major reactive component was the ∼ 100 kDa catalytic α subunit. A less prominent band migrating as a sharper, lower molecular weight (50 kDa) component than the kidney Na,K-ATPase β subunit is apparent in reticulocytes but not mature cells. Membranes from both genotypes showed identical immunologically reactive peptides, except for the lower intensity of the α subunit in the mature cells of the low- compared to high-K + sheep. Following culture of both types, moderate reduction in reactivity was apparent. Immunologically reactive α subunit as well as the 50 kDa species were detected in membranous material shed into the culture medium. This material was functionally inactive (lack of both [ 3 H] ouabain binding and Na + -dependent phosphorylation of Na,K-ATPase). The existence in reticulocytes of an intracellular pool of ouabain binding sites is evidenced in appearance of extra sites following rapid ATP depletion and also after addition of chloroquine. Taken together, these findings are consistent with a maturation-associated decrease of sodium pumps by a process of membrane recycling, processing and, to some extent, exocytosis

Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

Science.gov (United States)

Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

2003-01-01

We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces. Abaxial surfaces also produced higher reflectances, in general, in the 400-800 nm spectrum.

The Logistic Maturity Model: Application to a Fashion Company

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Claudia Battista

2013-08-01

Full Text Available This paper describes the structure of the logistic maturity model (LMM in detail and shows the possible improvements that can be achieved by using this model in terms of the identification of the most appropriate actions to be taken in order to increase the performance of the logistics processes in industrial companies. The paper also gives an example of the LMM’s application to a famous Italian female fashion firm, which decided to use the model as a guideline for the optimization of its supply chain. Relying on a 5-level maturity staircase, specific achievement indicators as well as key performance indicators and best practices are defined and related to each logistics area/process/sub-process, allowing any user to easily and rapidly understand the more critical logistical issues in terms of process immaturity.

Assessment of cortical maturation with prenatal MRI. Part I: normal cortical maturation

Energy Technology Data Exchange (ETDEWEB)

Fogliarini, Celine [Faculte Timone, Centre de Resonance Magnetique Biologique et Medicale, Marseille (France); Chaumoitre, Katia [Hopital Nord, Department of Radiology, Marseille (France); Chapon, Frederique; Levrier, Olivier; Girard, Nadine [Hopital Timone, Department of Neuroradiology, Marseille Cedex 5 (France); Fernandez, Carla; Figarella-Branger, Dominique [Hopital Timone, Department of Pathology, Marseille (France)

2005-08-01

Cortical maturation, especially gyral formation, follows a temporospatial schedule and is a good marker of fetal maturation. Although ultrasonography is still the imaging method of choice to evaluate fetal anatomy, MRI has an increasingly important role in the detection of brain abnormalities, especially of cortical development. Knowledge of MRI techniques in utero with the advantages and disadvantages of some sequences is necessary, in order to try to optimize the different magnetic resonance sequences to be able to make an early diagnosis. The different steps of cortical maturation known from histology represent the background necessary for the understanding of maturation in order to be then able to evaluate brain maturation through neuroimaging. Illustrations of the normal cortical maturation are given for each step accessible to MRI for both the cerebral hemispheres and the posterior fossa. (orig.)

Assessment of cortical maturation with prenatal MRI. Part I: normal cortical maturation

International Nuclear Information System (INIS)

Fogliarini, Celine; Chaumoitre, Katia; Chapon, Frederique; Levrier, Olivier; Girard, Nadine; Fernandez, Carla; Figarella-Branger, Dominique

2005-01-01

Cortical maturation, especially gyral formation, follows a temporospatial schedule and is a good marker of fetal maturation. Although ultrasonography is still the imaging method of choice to evaluate fetal anatomy, MRI has an increasingly important role in the detection of brain abnormalities, especially of cortical development. Knowledge of MRI techniques in utero with the advantages and disadvantages of some sequences is necessary, in order to try to optimize the different magnetic resonance sequences to be able to make an early diagnosis. The different steps of cortical maturation known from histology represent the background necessary for the understanding of maturation in order to be then able to evaluate brain maturation through neuroimaging. Illustrations of the normal cortical maturation are given for each step accessible to MRI for both the cerebral hemispheres and the posterior fossa. (orig.)

ORGANIZATIONAL PROJECT MANAGEMENT MATURITY

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Yana Derenskaya

2017-11-01

Full Text Available The present article is aimed at developing a set of recommendations for achieving a higher level of organizational project maturity at a given enterprise. Methodology. For the purposes of the current research, the available information sources on the components of project management system are analysed; the essence of “organizational maturity” and the existing models of organizational maturity are studied. The method of systemic and structural analysis, as well as the method of logical generalization, are employed in order to study the existing models of organizational maturity, to describe levels of organizational maturity, and finally to develop a set of methodological recommendations for achieving a higher level of organizational project maturity at a given enterprise. The results of the research showed that the core elements of project management system are methodological, organizational, programtechnical, and motivational components. Project management encompasses a wide range of issues connected with organizational structure, project team, communication management, project participants, etc. However, the fundamental basis for developing project management concept within a given enterprise starts with defining its level of organizational maturity. The present paper describes various models of organizational maturity (staged, continuous, petal-shaped and their common types (H. Кеrzner Organizational Maturity Model, Berkeley PM Maturity Model, Organizational Project Management Maturity Model, Portfolio, Program & Project Management Maturity Model. The analysis of available theoretic works showed that the notion “organizational project maturity” refers to the capability of an enterprise to select projects and manage them with the intention of achieving its strategic goals in the most effective way. Importantly, the level of maturity can be improved by means of formalizing the acquired knowledge, regulating project-related activities

Fluorescent Gold Nanoprobes for the Sensitive and Selective Detection for Hg2+

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Chai Fang

2010-01-01

Full Text Available Abstract A simple, cost-effective yet rapid and sensitive sensor for on-site and real-time Hg2+ detection based on bovine serum albumin functionalized fluorescent gold nanoparticles as novel and environmentally friendly fluorescent probes was developed. Using this probe, aqueous Hg2+ can be detected at 0.1 nM in a facile way based on fluorescence quenching. This probe was also applied to determine the Hg2+ in the lake samples, and the results demonstrate low interference and high sensitivity.

A novel fluorescent retrograde neural tracer: cholera toxin B conjugated carbon dots

Science.gov (United States)

Zhou, Nan; Hao, Zeyu; Zhao, Xiaohuan; Maharjan, Suraj; Zhu, Shoujun; Song, Yubin; Yang, Bai; Lu, Laijin

2015-09-01

The retrograde neuroanatomical tracing method is a key technique to study the complex interconnections of the nervous system. Traditional tracers have several drawbacks, including time-consuming immunohistochemical or immunofluorescent staining procedures, rapid fluorescence quenching and low fluorescence intensity. Carbon dots (CDs) have been widely used as a fluorescent bio-probe due to their ultrasmall size, excellent optical properties, chemical stability, biocompatibility and low toxicity. Herein, we develop a novel fluorescent neural tracer: cholera toxin B-carbon dot conjugates (CTB-CDs). It can be taken up and retrogradely transported by neurons in the peripheral nervous system of rats. Our results show that CTB-CDs possess high photoluminescence intensity, good optical stability, a long shelf-life and non-toxicity. Tracing with CTB-CDs is a direct and more economical way of performing retrograde labelling experiments. Therefore, CTB-CDs are reliable fluorescent retrograde tracers.The retrograde neuroanatomical tracing method is a key technique to study the complex interconnections of the nervous system. Traditional tracers have several drawbacks, including time-consuming immunohistochemical or immunofluorescent staining procedures, rapid fluorescence quenching and low fluorescence intensity. Carbon dots (CDs) have been widely used as a fluorescent bio-probe due to their ultrasmall size, excellent optical properties, chemical stability, biocompatibility and low toxicity. Herein, we develop a novel fluorescent neural tracer: cholera toxin B-carbon dot conjugates (CTB-CDs). It can be taken up and retrogradely transported by neurons in the peripheral nervous system of rats. Our results show that CTB-CDs possess high photoluminescence intensity, good optical stability, a long shelf-life and non-toxicity. Tracing with CTB-CDs is a direct and more economical way of performing retrograde labelling experiments. Therefore, CTB-CDs are reliable fluorescent retrograde

Optofluidic fluorescent imaging cytometry on a cell phone.

Science.gov (United States)

Zhu, Hongying; Mavandadi, Sam; Coskun, Ahmet F; Yaglidere, Oguzhan; Ozcan, Aydogan

2011-09-01

Fluorescent microscopy and flow cytometry are widely used tools in biomedical sciences. Cost-effective translation of these technologies to remote and resource-limited environments could create new opportunities especially for telemedicine applications. Toward this direction, here we demonstrate the integration of imaging cytometry and fluorescent microscopy on a cell phone using a compact, lightweight, and cost-effective optofluidic attachment. In this cell-phone-based optofluidic imaging cytometry platform, fluorescently labeled particles or cells of interest are continuously delivered to our imaging volume through a disposable microfluidic channel that is positioned above the existing camera unit of the cell phone. The same microfluidic device also acts as a multilayered optofluidic waveguide and efficiently guides our excitation light, which is butt-coupled from the side facets of our microfluidic channel using inexpensive light-emitting diodes. Since the excitation of the sample volume occurs through guided waves that propagate perpendicular to the detection path, our cell-phone camera can record fluorescent movies of the specimens as they are flowing through the microchannel. The digital frames of these fluorescent movies are then rapidly processed to quantify the count and the density of the labeled particles/cells within the target solution of interest. We tested the performance of our cell-phone-based imaging cytometer by measuring the density of white blood cells in human blood samples, which provided a decent match to a commercially available hematology analyzer. We further characterized the imaging quality of the same platform to demonstrate a spatial resolution of ~2 μm. This cell-phone-enabled optofluidic imaging flow cytometer could especially be useful for rapid and sensitive imaging of bodily fluids for conducting various cell counts (e.g., toward monitoring of HIV+ patients) or rare cell analysis as well as for screening of water quality in

Designing of fluorescent and magnetic imprinted polymer for rapid, selective and sensitive detection of imidacloprid via activators regenerated by the electron transfer-atom transfer radical polymerization (ARGET-ATRP) technique

Science.gov (United States)

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

2018-05-01

In this work, we report on a dual-behavior electrochemical/optical sensor for sensitive determination of Imidacloprid by fluorescent dye (fluorescein, FL) and imprinted polymer modified europium doped superparamagnetic iron oxide nanoparticles (FL@SPIONs@MIP). The imidacloprid (IMD)-imprinted polymer was directly synthesized on the Eu-SPIONs surface via Activators regenerated by the electron transfer-atom transfer radical polymerization (ARGET-ATRP) technique. Preparation, characterization and application of the prepared FL@SPIONs@MIP were systematically investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), fluorescence spectroscopy and electrochemical techniques. The electrochemical experiments exhibited a remarkable selectivity of the prepared sensor towards IMD. Determination of IMD by the square wave stripping voltammetry method represented a wide linear range of 0.059-0.791 μg L-1 with a detection limit of 0.0125 μg L-1. In addition, the fluorescence method shows a linear range of 0.039-0.942 μg L-1 and LOD of 0.0108 μg L-1. The fluorescence property of prepared FL@SPIONs@MIP was used for rapid, on-spot but selective detection of IMD in real samples. The proposed electrode displayed excellent repeatability and long-term stability and was successfully applied for quantitative and trace level determination of IMD in several real samples.

Rapid and sensitive detection of clenbuterol using a fluorescence nanosensor based on diazo coupling mechanism

Science.gov (United States)

Thanh Hop Tran, Thi; Huong Do, Thi Mai; Hoang, Mai Ha; Tuyen Nguyen, Duc; Le, Quang Tuan; Nghia Nguyen, Duc; Ngo, Trinh Tung

2015-01-01

In this paper, the fluorescence resonance energy transfer (FRET) effect has been used for fabrication of nanosensor for the detection of clenbuterol. In the nanosensor, the CdTe quantum dots (QDs) are the donors while the acceptor is the super-macromolecule formed by the diazoation coupling mechanism between diazo clenbuterol and naphthylethylene diamine. Changes in fluorescence intensities of nanosensor were used to determine the clenbuterol concentration. We have successfully fabricated a nanosensor for detection of clenbuterol sensible to clenbuterol concentration of 10-12 g ml-1.

Rapidly processable radiographic material

International Nuclear Information System (INIS)

Brabandere, L.A. de; Borginon, H.A.; Pattyn, H.A.; Pollet, R.J.

1981-01-01

A new rapidly processable radiographic silver halide material is described for use in mammography and non-destructive testing of industrial materials. The radiographic material is used for direct exposure to penetrating radiation without the use of fluorescent-intensifying screens. It consists of a transparent support with a layer of hydrophilic colloid silver halide emulsion on one or both sides. Examples of the preparation of three different silver halide emulsions are given including the use of different chemical sensitizers. These new radiographic materials have good resistance to the formation of pressure marks in rapid processing apparatus and they have improved sensitivity for direct exposure to penetrating radiation compared to conventional radiographic emulsions. (U.K.)

Fluorescent carbon dots and nanodiamonds for biological imaging: preparation, application, pharmacokinetics and toxicity.

Science.gov (United States)

Liu, Jia-Hui; Yang, Sheng-Tao; Chen, Xin-Xin; Wang, Haifang

2012-10-01

The rapid advancement of nanotechnology has brought us some new types of fluorescent probes, which are indispensable for bioimaging in life sciences. Because of their innate biocompatibility, good resistance against photobleaching, long fluorescence lifetime and wide fluorescence spectral region, fluorescent carbon quantum dots (C-Dots) and nanosized diamonds (nanodiamonds, NDs) are gradually evolving into promising reagents for bioimaging. In this review, we summarize the recent achievements in fluorescent C-Dots and NDs with emphases on their preparation, properties, imaging application, pharmacokinetics and toxicity. Perspectives on further investigations and opportunities to develop C-Dots and NDs into the safer and more sensitive imaging probes for both living cells and animal models are discussed.

Hyperspectral small animal fluorescence imaging: spectral selection imaging

Science.gov (United States)

Leavesley, Silas; Jiang, Yanan; Patsekin, Valery; Hall, Heidi; Vizard, Douglas; Robinson, J. Paul

2008-02-01

Molecular imaging is a rapidly growing area of research, fueled by needs in pharmaceutical drug-development for methods for high-throughput screening, pre-clinical and clinical screening for visualizing tumor growth and drug targeting, and a growing number of applications in the molecular biology fields. Small animal fluorescence imaging employs fluorescent probes to target molecular events in vivo, with a large number of molecular targeting probes readily available. The ease at which new targeting compounds can be developed, the short acquisition times, and the low cost (compared to microCT, MRI, or PET) makes fluorescence imaging attractive. However, small animal fluorescence imaging suffers from high optical scattering, absorption, and autofluorescence. Much of these problems can be overcome through multispectral imaging techniques, which collect images at different fluorescence emission wavelengths, followed by analysis, classification, and spectral deconvolution methods to isolate signals from fluorescence emission. We present an alternative to the current method, using hyperspectral excitation scanning (spectral selection imaging), a technique that allows excitation at any wavelength in the visible and near-infrared wavelength range. In many cases, excitation imaging may be more effective at identifying specific fluorescence signals because of the higher complexity of the fluorophore excitation spectrum. Because the excitation is filtered and not the emission, the resolution limit and image shift imposed by acousto-optic tunable filters have no effect on imager performance. We will discuss design of the imager, optimizing the imager for use in small animal fluorescence imaging, and application of spectral analysis and classification methods for identifying specific fluorescence signals.

Development and Comparison of a Rapid Isothermal Nucleic Acid Amplification Test for Typing of Herpes Simplex Virus Types 1 and 2 on a Portable Fluorescence Detector

Science.gov (United States)

Tong, Yanhong; McCarthy, Kaitlin; Kong, Huimin; Lemieux, Bertrand

2013-01-01

We have developed a rapid and simple molecular test, the IsoGlow HSV Typing assay, for the detection and typing of herpes simplex virus (type 1 and 2) from genital or oral lesions. Clinical samples suspended in viral transport mediums are simply diluted and then added to a helicase-dependent amplification master mix. The amplification and detection were performed on a portable fluorescence detector called the FireFly instrument. Detection of amplification products is based on end-point analysis using cycling probe technology. An internal control nucleic acid was included in the amplification master mix to monitor the presence of amplification inhibitors in the samples. Because the device has only two fluorescence detection channels, two strategies were developed and compared to detect the internal control template: internal control detected by melting curve analysis using a dual-labeled probe, versus internal control detection using end-point fluorescence release by a CPT probe at a lower temperature. Both have a total turnaround time of about 1 hour. Clinical performance relative to herpes viral culture was evaluated using 176 clinical specimens. Both formats of the IsoGlow HSV typing assay had sensitivities comparable to that of the Food and Drug Administration–cleared IsoAmp HSV (BioHelix Corp., Beverly MA) test and specificity for the two types of HSV comparable to that of ELVIS HSV (Diagnostic Hybrids, Athens, OH). PMID:22951487

Fluorescence excitation-emission matrix (EEM) spectroscopy for rapid identification and quality evaluation of cell culture media components.

Science.gov (United States)

Li, Boyan; Ryan, Paul W; Shanahan, Michael; Leister, Kirk J; Ryder, Alan G

2011-11-01

The application of fluorescence excitation-emission matrix (EEM) spectroscopy to the quantitative analysis of complex, aqueous solutions of cell culture media components was investigated. These components, yeastolate, phytone, recombinant human insulin, eRDF basal medium, and four different chemically defined (CD) media, are used for the formulation of basal and feed media employed in the production of recombinant proteins using a Chinese Hamster Ovary (CHO) cell based process. The comprehensive analysis (either identification or quality assessment) of these materials using chromatographic methods is time consuming and expensive and is not suitable for high-throughput quality control. The use of EEM in conjunction with multiway chemometric methods provided a rapid, nondestructive analytical method suitable for the screening of large numbers of samples. Here we used multiway robust principal component analysis (MROBPCA) in conjunction with n-way partial least squares discriminant analysis (NPLS-DA) to develop a robust routine for both the identification and quality evaluation of these important cell culture materials. These methods are applicable to a wide range of complex mixtures because they do not rely on any predetermined compositional or property information, thus making them potentially very useful for sample handling, tracking, and quality assessment in biopharmaceutical industries.

Assessing healthcare process maturity: challenges of using a business process maturity model

NARCIS (Netherlands)

Tarhan, A.; Turetken, O.; van den Biggelaar, F.J.H.M.

2015-01-01

Doi: 10.4108/icst.pervasivehealth.2015.259105 The quality of healthcare services is influenced by the maturity of healthcare processes used to develop it. A maturity model is an instrument to assess and continually improve organizational processes. In the last decade, a number of maturity models

Diagnostic assessment of skeletal maturity through dental maturation in Hispanic growing individuals

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Alejandra Cisternas

2017-01-01

Full Text Available Background: The aim of this study was to explore dental maturation as a diagnostic test for skeletal maturation. Materials and Methods: Six hundred and fifty-seven growing individuals were classified according to their cervical vertebral maturity and dental maturity, both determined in lateral cephalograms and panoramic radiographs, respectively. The correlation between cervical and dental stages was established for each gender. A receiver operating characteristic curve analysis was made, and sensitivity and specificity values were established. Results: Correlation was found between cervical and dental maturation for females (r = 0.73; P<0.001 and males (r = 0.60; P<0.001. Sensitivity for dental Stage F, as an indicator of a postmaturation peak stage, was 87.21% for females and 97.1% for males, whereas specificity for the same stage was 82.92% and 72.3% for females and males, respectively. Conclusions: Dental maturation evaluation could contribute determining whether a patient is in a pre- or post-growth spurt stage.

Correlation between Dental Maturity by Demirjian Method and Skeletal Maturity by Cervical Vertebral Maturity Method using Panoramic Radiograph and Lateral Cephalogram

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Madhusudhanan Mallika Mini

2017-01-01

Full Text Available Introduction: Radiographs are effective tools in assessing the stages of bone maturation in dentistry. The cervical vertebral maturation method is a proven effective tool in assessing the adolescent growth spurt than hand-wrist radiographs in an individual. Assessment of dental calcification stages are a reliable method for determining dental maturity. Panoramic imaging can be used as the primary imaging modality for assessing maturity if a correlation can be found out between tooth calcification stages and cervical vertebral maturation stages. This study was conducted to determine the correlation between dental maturity stage and cervical vertebral maturity stage and to estimate predictor variables for cervical vertebral maturation stages (CVMS stratified by gender in a tertiary hospital setting. Materials and Methods: A descriptive study was conducted among patients accessing orthodontic care in radiology outpatient clinic, Oral Medicine and Radiology department, Government Dental College Thiruvananthapuram for a period of 15 months. Participants were selected between the ages of 8 and 16 years. Panoramic radiographs and lateral cephalograms were used to determine dental maturity stages using Demirjian method and CVMS using Bacetti and Franchi method, respectively. Results: One hundred patients (males = 46, females = 54 were included in the study; the spearman rank order correlation revealed significant relationship. The correlation ranged from 0.61 to 0.74 for females and 0.48 to 0.51 for males. Second premolar showed highest correlation and canine the lowest for both females and males. Stage G of mandibular second premolar signifies the pubertal growth period in this study population. By ordinal regression model, G stage of second premolar was found to be a significant predictor in males and stage H followed by G and F in females for the age group of 12–14 years. Conclusion: Dental maturation stages were significantly correlated with CVMS

Mechanism of Na,K-ATPase decline during sheep red cell maturation

Energy Technology Data Exchange (ETDEWEB)

Grafova, E.; Blostein, R.

1987-05-01

Na,K-ATPase of immature and mature sheep red cells of both the high-K/sup +/ and low-K/sup +/ genotypes as well as cells of both types matured in vitro was detected using polyclonal antiserum to sheep kidney Na,K-ATPase. Following SDS-PAGE and immunoblotting, the major reactive component was the approx. 100 kDa catalytic ..cap alpha.. subunit. A less prominent band migrating as a sharper, lower molecular weight (50 kDa) component than the kidney Na,K-ATPase ..beta.. subunit is apparent in reticulocytes but not mature cells. Membranes from both genotypes showed identical immunologically reactive peptides, except for the lower intensity of the ..cap alpha.. subunit in the mature cells of the low- compared to high-K/sup +/ sheep. Following culture of both types, moderate reduction in reactivity was apparent. Immunologically reactive ..cap alpha.. subunit as well as the 50 kDa species were detected in membranous material shed into the culture medium. This material was functionally inactive (lack of both (/sup 3/H) ouabain binding and Na/sup +/-dependent phosphorylation of Na,K-ATPase). The existence in reticulocytes of an intracellular pool of ouabain binding sites is evidenced in appearance of extra sites following rapid ATP depletion and also after addition of chloroquine. Taken together, these findings are consistent with a maturation-associated decrease of sodium pumps by a process of membrane recycling, processing and, to some extent, exocytosis.

Tectonic heat flow modelling for basin maturation - Implications for frontier areas in the mediterranean

NARCIS (Netherlands)

Wees, J.D. van; Bonte, D.; Nelskamp, S.

2009-01-01

Basement heat flow is one of the most influential parameters on basin maturity. Although rapid progress has been made in the development of tectonic models capable of modelling the thermal consequences of basin formation, these models are hardly used in basin modelling. To better predict heat flows

Fluorescent proteins such as eGFP lead to catalytic oxidative stress in cells.

Science.gov (United States)

Ganini, Douglas; Leinisch, Fabian; Kumar, Ashutosh; Jiang, JinJie; Tokar, Erik J; Malone, Christine C; Petrovich, Robert M; Mason, Ronald P

2017-08-01

Fluorescent proteins are an important tool that has become omnipresent in life sciences research. They are frequently used for localization of proteins and monitoring of cells [1,2]. Green fluorescent protein (GFP) was the first and has been the most used fluorescent protein. Enhanced GFP (eGFP) was optimized from wild-type GFP for increased fluorescence yield and improved expression in mammalian systems [3]. Many GFP-like fluorescent proteins have been discovered, optimized or created, such as the red fluorescent protein TagRFP [4]. Fluorescent proteins are expressed colorless and immature and, for eGFP, the conversion to the fluorescent form, mature, is known to produce one equivalent of hydrogen peroxide (H 2 O 2 ) per molecule of chromophore [5,6]. Even though it has been proposed that this process is non-catalytic and generates nontoxic levels of H 2 O 2 [6], this study investigates the role of fluorescent proteins in generating free radicals and inducing oxidative stress in biological systems. Immature eGFP and TagRFP catalytically generate the free radical superoxide anion (O 2 •- ) and H 2 O 2 in the presence of NADH. Generation of the free radical O 2 •- and H 2 O 2 by eGFP in the presence of NADH affects the gene expression of cells. Many biological pathways are altered, such as a decrease in HIF1α stabilization and activity. The biological pathways altered by eGFP are known to be implicated in the pathophysiology of many diseases associated with oxidative stress; therefore, it is critical that such experiments using fluorescent proteins are validated with alternative methodologies and the results are carefully interpreted. Since cells inevitably experience oxidative stress when fluorescent proteins are expressed, the use of this tool for cell labeling and in vivo cell tracing also requires validation using alternative methodologies. Published by Elsevier B.V.

Activity of daptomycin- and vancomycin-loaded poly-epsilon-caprolactone microparticles against mature staphylococcal biofilms

Directory of Open Access Journals (Sweden)

Santos Ferreira I

2015-07-01

microcalorimetry also revealed that lower concentrations of daptomycin-loaded microparticles were required to completely inhibit the recovery of mature MRSA and S. epidermidis biofilms. Further characterization of the effect of daptomycin-loaded PCL microparticles on mature biofilms was performed by fluorescence in situ hybridization. Fluorescence in situ hybridization showed an important reduction in MRSA biofilm, whereas S. epidermidis biofilms, although inhibited, were not eradicated. In addition, an important attachment of the microparticles to MRSA and S. epidermidis biofilms was observed. Finally, all formulations proved to be biocompatible with both ISO compliant L929 fibroblasts and human MG63 osteoblast-like cells.Keywords: antibiotic release, Staphylococcus aureus, Staphylococcus epidermidis, fluorescence in situ hybridization, isothermal microcalorimetry

Fluorescent Lipids: Functional Parts of Fusogenic Liposomes and Tools for Cell Membrane Labeling and Visualization

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Christian Kleusch

2012-01-01

Full Text Available In this paper a rapid and highly efficient method for controlled incorporation of fluorescent lipids into living mammalian cells is introduced. Here, the fluorescent molecules have two consecutive functions: First, they trigger rapid membrane fusion between cellular plasma membranes and the lipid bilayers of their carrier particles, so called fusogenic liposomes, and second, after insertion into cellular membranes these molecules enable fluorescence imaging of cell membranes and membrane traffic processes. We tested the fluorescent derivatives of the following essential membrane lipids for membrane fusion: Ceramide, sphingomyelin, phosphocholine, phosphatidylinositol-bisphosphate, ganglioside, cholesterol, and cholesteryl ester. Our results show that all probed lipids could more efficiently be incorporated into the plasma membrane of living cells than by using other methods. Moreover, labeling occurred in a gentle manner under classical cell culture conditions reducing cellular stress responses. Staining procedures were monitored by fluorescence microscopy and it was observed that sphingolipids and cholesterol containing free hydroxyl groups exhibit a decreased distribution velocity as well as a longer persistence in the plasma membrane compared to lipids without hydroxyl groups like phospholipids or other artificial lipid analogs. After membrane staining, the fluorescent molecules were sorted into membranes of cell organelles according to their chemical properties and biological functions without any influence of the delivery system.

Fluorescence reporter gene platform applicable for the detection and quantification of horizontal gene transfer in anoxic environments

DEFF Research Database (Denmark)

Pinilla Redondo, Rafael

of the impact the pH has on their fluorescence intensities. Validation of the dual-labelling system for the study of HGT in anoxic milieus. Methods: The time-course fluorescent recovery of mCherry and GFPmut3 in vivo, as well as the effect of the extracellular pH on fluorescence was monitored through flow......Cherry is limited by environmental constraints that affect the correct maturation of their fluorophores, such as oxygen availability and pH levels. Few studies have focused on elucidating their impact, and the sheer amount of distinct protein variants requires each system to be examined in an individual fashion....... The wealth of ecologically and clinically relevant oxygen-deprived micro-habitats in which bacteria thrive, calls for the urgent development of suitable tools that permit their study. Objectives: Development of an aerobic fluorescence recovery method for mCherry and GFPmut3, as well as characterisation...

EVALUATION OF THE BIOSOLIDS COMPOST MATURITY IN SOUTH ISFAHAN WASTEWATER TREATMENT PLANT

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H. Alidadi, A. R. Parvaresh, M. R. Shahmansouri, H. Pourmoghadas

2008-04-01

Full Text Available The composting process is a useful method of producing a stabilized material that can be used as a source of nutrients and soil conditioner. Maturity of compost is essential for its optimal use as a soil amendment and a source of plant nutrients as well. Immature composts pose problems of malodors and flies and phytotoxicity and pollution during use. Stability and maturity both are required for compost quality control. Compost maturity tests can be classified into physical, chemical, plant, and microbial activity assays. In this study, several methods of evaluating the stability and maturity of composted biosolids were compared based on chemical and biological properties. The sludge used of windrow composting was obtained from the drying beds of South Isfahan wastewater treatment plant. The results showed that, C/N ratio after 100 days of composting reached to 15/1; NH4/NO3 ratio decreased with increase of the time dewatered sludge compost, which this loss is 57.3%. The content of volatile solids, 28.8% decreased with composting time. The number of fecal coliforms in the initial sewage sludge compost was 17.9´106 and at the end of composting was 898MPN/g of total solids and the compost process provided class A pathogen criteria. Use of chemical and biological parameters exhibited three phases: rapid decomposition (day 40, stabilization (day 80 and maturation (day 100 in biosolids compost. Thus, the biosolid compost was mature and ready for use as an agricultural substrate after about 100 days of composting.

Fluorescent nanodiamond-bacteriophage conjugates maintain host specificity.

Science.gov (United States)

Trinh, Jimmy T; Alkahtani, Masfer H; Rampersaud, Isaac; Rampersaud, Arfaan; Scully, Marlan; Young, Ryland F; Hemmer, Philip; Zeng, Lanying

2018-06-01

Rapid identification of specific bacterial strains within clinical, environmental, and food samples can facilitate the prevention and treatment of disease. Fluorescent nanodiamonds (FNDs) are being developed as biomarkers in biology and medicine, due to their excellent imaging properties, ability to accept surface modifications, and lack of toxicity. Bacteriophages, the viruses of bacteria, can have exquisite specificity for certain hosts. We propose to exploit the properties of FNDs and phages to develop phages conjugated with FNDs as long-lived fluorescent diagnostic reagents. In this study, we develop a simple procedure to create such fluorescent probes by functionalizing the FNDs and phages with streptavidin and biotin, respectively. We find that the FND-phage conjugates retain the favorable characteristics of the individual components and can discern their proper host within a mixture. This technology may be further explored using different phage/bacteria systems, different FND color centers and alternate chemical labeling schemes for additional means of bacterial identification and new single-cell/virus studies. © 2018 Wiley Periodicals, Inc.

Quantum dots versus organic fluorophores in fluorescent deep-tissue imaging--merits and demerits.

Science.gov (United States)

Bakalova, Rumiana; Zhelev, Zhivko; Gadjeva, Veselina

2008-12-01

The use of fluorescence in deep-tissue imaging is rapidly expanding in last several years. The progress in fluorescent molecular probes and fluorescent imaging techniques gives an opportunity to detect single cells and even molecular targets in live organisms. The highly sensitive and high-speed fluorescent molecular sensors and detection devices allow the application of fluorescence in functional imaging. With the development of novel bright fluorophores based on nanotechnologies and 3D fluorescence scanners with high spatial and temporal resolution, the fluorescent imaging has a potential to become an alternative of the other non-invasive imaging techniques as magnetic resonance imaging, positron-emission tomography, X-ray, computing tomography. The fluorescent imaging has also a potential to give a real map of human anatomy and physiology. The current review outlines the advantages of fluorescent nanoparticles over conventional organic dyes in deep-tissue imaging in vivo and defines the major requirements to the "perfect fluorophore". The analysis proceeds from the basic principles of fluorescence and major characteristics of fluorophores, light-tissue interactions, and major limitations of fluorescent deep-tissue imaging. The article is addressed to a broad readership - from specialists in this field to university students.

Root architecture and wind-firmness of mature Pinus pinaster.

Science.gov (United States)

Danjon, Frédéric; Fourcaud, Thierry; Bert, Didier

2005-11-01

This study aims to link three-dimensional coarse root architecture to tree stability in mature timber trees with an average of 1-m rooting depth. Undamaged and uprooted trees were sampled in a stand damaged by a storm. Root architecture was measured by three-dimensional (3-D) digitizing. The distribution of root volume by root type and in wind-oriented sectors was analysed. Mature Pinus pinaster root systems were organized in a rigid 'cage' composed of a taproot, the zone of rapid taper of horizontal surface roots and numerous sinkers and deep roots, imprisoning a large mass of soil and guyed by long horizontal surface roots. Key compartments for stability exhibited strong selective leeward or windward reinforcement. Uprooted trees showed a lower cage volume, a larger proportion of oblique and intermediate depth horizontal roots and less wind-oriented root reinforcement. Pinus pinaster stability on moderately deep soils is optimized through a typical rooting pattern and a considerable structural adaptation to the prevailing wind and soil profile.

Rapid determination of trace phosphorus, sulfur, chlorine, bromine and iodine by energy dispersive X-ray fluorescence analysis with monochromatic excitations

International Nuclear Information System (INIS)

Wakisaka, Tatsushi; Morita, Naoki; Hirabayashi, Tadashi; Nakahara, Taketoshi

1998-01-01

A useful and rapid procedure is described for the determination of trace phosphorus, sulfur, chlorine, bromine, and iodine by means of an energy dispersive X-ray fluorescence spectrometer (EDXRF) with monochromatic excitations. Using monochromatic excitations, the detection limits for phosphorus, sulfur, chlorine (Cr-Kα, 5.41 keV), bromine (Mo-Kα, 17.44 keV), and iodine (W-continuum, 40 keV) were found to be 4.6, 1.7, 0.7, 0.09 and 0.5 μg g -1 , respectively. The relative standard deviations in five replicate measurements were 0.9-1.3%. The proposed method was applied to the direct determination of sulfur in the NIST Residual Fuel Oil, and others. The results obtained by the proposed method were in good agreement with the certified values. Bromine in a seawater sample, as well as iodine and bromine in a brine sample were determined by the proposed method. The obtained results were in good agreement with those obtained by ion chromatography. (author)

Experimental design and quality assurance: in situ fluorescence instrumentation

Science.gov (United States)

Conmy, Robyn N.; Del Castillo, Carlos E.; Downing, Bryan D.; Chen, Robert F.

2014-01-01

Both instrument design and capabilities of fluorescence spectroscopy have greatly advanced over the last several decades. Advancements include solid-state excitation sources, integration of fiber optic technology, highly sensitive multichannel detectors, rapid-scan monochromators, sensitive spectral correction techniques, and improve data manipulation software (Christian et al., 1981, Lochmuller and Saavedra, 1986; Cabniss and Shuman, 1987; Lakowicz, 2006; Hudson et al., 2007). The cumulative effect of these improvements have pushed the limits and expanded the application of fluorescence techniques to numerous scientific research fields. One of the more powerful advancements is the ability to obtain in situ fluorescence measurements of natural waters (Moore, 1994). The development of submersible fluorescence instruments has been made possible by component miniaturization and power reduction including advances in light sources technologies (light-emitting diodes, xenon lamps, ultraviolet [UV] lasers) and the compatible integration of new optical instruments with various sampling platforms (Twardowski et at., 2005 and references therein). The development of robust field sensors skirt the need for cumbersome and or time-consuming filtration techniques, the potential artifacts associated with sample storage, and coarse sampling designs by increasing spatiotemporal resolution (Chen, 1999; Robinson and Glenn, 1999). The ability to obtain rapid, high-quality, highly sensitive measurements over steep gradients has revolutionized investigations of dissolved organic matter (DOM) optical properties, thereby enabling researchers to address novel biogeochemical questions regarding colored or chromophoric DOM (CDOM). This chapter is dedicated to the origin, design, calibration, and use of in situ field fluorometers. It will serve as a review of considerations to be accounted for during the operation of fluorescence field sensors and call attention to areas of concern when making

Scientific maturity of purchasing management research : a rapidly growing puppy that still has to learn some manners

NARCIS (Netherlands)

Heijboer, Govert

The field of purchasing management (PM) is still young. In this paper we investigate the status of PM research by looking at the historical development of other research fields that have already matured. For this investigation we categorise scientific research as (1) either deductive (theoretical)

The use of rapid quantitative x-ray fluorescence analysis in paper manufacturing and construction materials industry

International Nuclear Information System (INIS)

Kocman, V.; Foley, L.; Woodger, S.C.

1985-01-01

A modern analytical laboratory of a large corporation manufacturing paper, construction materials and chemicals must be sufficiently diversified in methodology to provide accurate results in the shortest possible time. Among other techniques the implementation of an automated ''menu'' driven wavelength dispersive spectrometer allowed for the setting-up of a variety of quantitative X-ray fluorescence methods. An overview of these methods is given as presented at the 33rd. Annual Conference on the Application of X-ray Fluorescence Analysis in Denver, Colorado, 1984

Small acid soluble proteins for rapid spore identification.

Energy Technology Data Exchange (ETDEWEB)

Branda, Steven S.; Lane, Todd W.; VanderNoot, Victoria A.; Jokerst, Amanda S.

2006-12-01

This one year LDRD addressed the problem of rapid characterization of bacterial spores such as those from the genus Bacillus, the group that contains pathogenic spores such as B. anthracis. In this effort we addressed the feasibility of using a proteomics based approach to spore characterization using a subset of conserved spore proteins known as the small acid soluble proteins or SASPs. We proposed developing techniques that built on our previous expertise in microseparations to rapidly characterize or identify spores. An alternative SASP extraction method was developed that was amenable to both the subsequent fluorescent labeling required for laser-induced fluorescence detection and the low ionic strength requirements for isoelectric focusing. For the microseparations, both capillary isoelectric focusing and chip gel electrophoresis were employed. A variety of methods were evaluated to improve the molecular weight resolution for the SASPs, which are in a molecular weight range that is not well resolved by the current methods. Isoelectric focusing was optimized and employed to resolve the SASPs using UV absorbance detection. Proteomic signatures of native wild type Bacillus spores and clones genetically engineered to produce altered SASP patterns were assessed by slab gel electrophoresis, capillary isoelectric focusing with absorbance detection as well as microchip based gel electrophoresis employing sensitive laser-induced fluorescence detection.

Novel maturity parameters for mature to over-mature source rocks and oils based on the distribution of phenanthrene series compounds

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Zixiang Wang

2016-03-01

Two additional novel and an optimized maturation parameters based on the distribution of phenanthrene series compounds are proposed and their relationships to EasyRo% (x are established: log(MPs/P = 0.19x + 0.08 (0.9% < EasyRo% < 2.1%; log(MPs/P = 0.64x − 0.86 (2.1% < EasyRo% < 3.4%; log(DMPs/TMPs = 0.71x − 0.55 (0.9% < EasyRo% < 3.4%; log(MTR = 0.84x − 0.75 (0.9% < EasyRo% < 3.4%. These significant positive correlations are strong argument for using log(MPs/P, log(DMPs/TMPs and log(MTR as maturity parameters, especially for mature to over-mature source rocks.

Rapid Identification of Staphylococcus aureus Directly from Blood Cultures by Fluorescence In Situ Hybridization with Peptide Nucleic Acid Probes

Science.gov (United States)

Oliveira, Kenneth; Procop, Gary W.; Wilson, Deborah; Coull, James; Stender, Henrik

2002-01-01

A new fluorescence in situ hybridization (FISH) method with peptide nucleic acid (PNA) probes for identification of Staphylococcus aureus directly from positive blood culture bottles that contain gram-positive cocci in clusters (GPCC) is described. The test (the S. aureus PNA FISH assay) is based on a fluorescein-labeled PNA probe that targets a species-specific sequence of the 16S rRNA of S. aureus. Evaluations with 17 reference strains and 48 clinical isolates, including methicillin-resistant and methicillin-susceptible S. aureus species, coagulase-negative Staphylococcus species, and other clinically relevant and phylogenetically related bacteria and yeast species, showed that the assay had 100% sensitivity and 96% specificity. Clinical trials with 87 blood cultures positive for GPCC correctly identified 36 of 37 (97%) of the S. aureus-positive cultures identified by standard microbiological methods. The positive and negative predictive values were 100 and 98%, respectively. It is concluded that this rapid method (2.5 h) for identification of S. aureus directly from blood culture bottles that contain GPCC offers important information for optimal antibiotic therapy. PMID:11773123

Highly selective rhodamine-based fluorescence turn-on chemosensor for Al3+ ion

Science.gov (United States)

Manjunath, Rangasamy; Kannan, Palaninathan

2018-05-01

A new rhodamine-based colorimetric and fluorescent turn-on chemosensor (L) has been designed and synthesized for selective and sensitive detection of Al3+ ion. The sensing behavior toward metal ion was investigated by UV/Vis and fluorescence spectroscopy. Upon addition of Al3+ ion to solution of L provided a visual color change as well as significantly fluorescent enhancement, while other metal ions including Na+, Mg2+, K+, Mn2+, Fe3+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+ and Hg2+ ions fails to generate a distinct color and spectral changes, the distinct color change and rapid switch-on fluorescence also provide naked eye detection for Al3+ ion. The mechanism involved equilibrium between non-fluorescent spirocyclic form and highly fluorescent ring open form process was utilized and 1:2 stoichiometry for L-Al3+ complex formed with an association constant of 1.42 × 103 M-1. Moreover, chemosensor L was applied for living cell imaging and confirmed that can be used as a fluorescent probe for monitoring Al3+ ion in living cells.

Rapid diagnosis of malaria by fluorescent microscopy with light microscope and interface filter

International Nuclear Information System (INIS)

Hussain, I.; Tayyib, M.; Farooq, M.; Ahmed, N.

2008-01-01

The present study is planned to compare acridine orange (A.O) staining with Giemsa staining by using light microscopy with IF and also with fluorescent microscopy for detection of parasites in peripheral blood of patients suffering from clinically suspected cases of malaria. 200 patients with fever and shivering were included. General investigations like Hb, TLC and platelets were done by sysmex K-1000. Thin and thick blood films were made and stained according to protocol given i.e. by Giemsa and AO stains and slides were examined by different microscopes i.e. light microscope, light microscope with IFS and fluorescent microscope. Out of 200 subjects, 170 (85%) patients showed positive parasitaemia and 30 (15%) subjects were negative for malaria parasites. fib, TLC and platelets were reduced when comparing with MP negative cases. IFS microscope with acridine orange staining showed early detection of malaria parasites by counting fewer fields as compared to light microscopy with Giemsa stains. Time consumed for detection of parasites was also significantly reduced in IFS microscope by using AO stains. (author)

Localizing Proteins in Fixed Giardia lamblia and Live Cultured Mammalian Cells by Confocal Fluorescence Microscopy.

Science.gov (United States)

Nyindodo-Ogari, Lilian; Schwartzbach, Steven D; Skalli, Omar; Estraño, Carlos E

2016-01-01

Confocal fluorescence microscopy and electron microscopy (EM) are complementary methods for studying the intracellular localization of proteins. Confocal fluorescence microscopy provides a rapid and technically simple method to identify the organelle in which a protein localizes but only EM can identify the suborganellular compartment in which that protein is present. Confocal fluorescence microscopy, however, can provide information not obtainable by EM but required to understand the dynamics and interactions of specific proteins. In addition, confocal fluorescence microscopy of cells transfected with a construct encoding a protein of interest fused to a fluorescent protein tag allows live cell studies of the subcellular localization of that protein and the monitoring in real time of its trafficking. Immunostaining methods for confocal fluorescence microscopy are also faster and less involved than those for EM allowing rapid optimization of the antibody dilution needed and a determination of whether protein antigenicity is maintained under fixation conditions used for EM immunogold labeling. This chapter details a method to determine by confocal fluorescence microscopy the intracellular localization of a protein by transfecting the organism of interest, in this case Giardia lamblia, with the cDNA encoding the protein of interest and then processing these organisms for double label immunofluorescence staining after chemical fixation. Also presented is a method to identify the organelle targeting information in the presequence of a precursor protein, in this case the presequence of the precursor to the Euglena light harvesting chlorophyll a/b binding protein of photosystem II precursor (pLHCPII), using live cell imaging of mammalian COS7 cells transiently transfected with a plasmid encoding a pLHCPII presequence fluorescent protein fusion and stained with organelle-specific fluorescent dyes.

A Graphene Oxide-Based Fluorescent Aptasensor for the Turn-on Detection of CCRF-CEM.

Science.gov (United States)

Tan, Jie; Lai, Zongqiang; Zhong, Liping; Zhang, Zhenghua; Zheng, Rong; Su, Jing; Huang, Yong; Huang, Panpan; Song, Hui; Yang, Nuo; Zhou, Sufang; Zhao, Yongxiang

2018-04-01

A convenient, low-cost, and highly sensitive fluorescent aptasensor for detection of leukemia has been developed based on graphene oxide-aptamer complex (GO-apt). Graphene oxide (GO) can absorb carboxyfluorescein-labeled Sgc8 aptamer (FAM-apt) by π-π stacking and quench the fluorescence through fluorescence resonance energy transfer (FRET). In the absence of Sgc8 target cell CCRF-CEM, the fluorescence is almost all quenched. Conversely, when the CCRF-CEM cells are added, the quenched fluorescence can be recovered rapidly and significantly. Therefore, based on the change of fluorescence signals, we can detect the number of CCRF-CEM cells in a wide range from 1 × 10 2 to 1 × 10 7  cells/mL with a limit of detection (LOD) of 10 cells/mL. Therefore, this strategy of graphene oxide-based fluorescent aptasensor may be promising for the detection of cancer.

Two colorimetric and ratiometric fluorescence probes for hydrogen sulfide based on AIE strategy of α-cyanostilbenes

Science.gov (United States)

Zhao, Baoying; Yang, Binsheng; Hu, Xiangquan; Liu, Bin

2018-06-01

Aggregation-induced emission (AIE) active fluorescent probes have attracted great potential in biological sensors. In this paper two cyanostilbene based fluorescence chemoprobe Cya-NO2 (1) and Cya-N3 (2) were developed and evaluated for the selective and sensitive detection of hydrogen sulfide (H2S). Both of these probes behave aggression-induced emission (AIE) activity which fluoresces in the red region with a large Stokes shift. They exhibit rapid response to H2S with enormous colorimetric and ratiometric fluorescent changes. They are readily employed for assessing intracellular H2S levels.

The total antioxidant capacity and fluorescence imaging of selected plant leaves commonly consumed in Brunei Darussalam

Science.gov (United States)

Watu, Aswani; Metussin, Nurzaidah; Yasin, Hartini M.; Usman, Anwar

2018-02-01

We investigated the total antioxidant capacity and fluorescence imaging of several selected plants, namely Centella asiatica, Aidia borneensis and Anacardium occidentale, which are grown and traditionally consumed in Brunei Darussalam. The total antioxidant capacities of aqueous-methanolic infusions of their leaves were measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, and microscopic fluorescence images were measured to identify the fluorescent substances bound in the leaves. We found that the total antioxidant capacity of their infusions is estimated to be 150, 25, 15 folds, respectively, lower compared with that of the standard gallic acid. Accordingly, we demonstrated that the relative antioxidant activity of young and matured leaves agrees with the intensity of red light emission of their fresh leaves upon UV excitation. Thus, this non-invasive spectroscopic method can be potentially utilized to indicate the antioxidants in plant leaves qualitatively.

A fluorescence anisotropy method for measuring protein concentration in complex cell culture media.

Science.gov (United States)

Groza, Radu Constantin; Calvet, Amandine; Ryder, Alan G

2014-04-22

The rapid, quantitative analysis of the complex cell culture media used in biopharmaceutical manufacturing is of critical importance. Requirements for cell culture media composition profiling, or changes in specific analyte concentrations (e.g. amino acids in the media or product protein in the bioprocess broth) often necessitate the use of complicated analytical methods and extensive sample handling. Rapid spectroscopic methods like multi-dimensional fluorescence (MDF) spectroscopy have been successfully applied for the routine determination of compositional changes in cell culture media and bioprocess broths. Quantifying macromolecules in cell culture media is a specific challenge as there is a need to implement measurements rapidly on the prepared media. However, the use of standard fluorescence spectroscopy is complicated by the emission overlap from many media components. Here, we demonstrate how combining anisotropy measurements with standard total synchronous fluorescence spectroscopy (TSFS) provides a rapid, accurate quantitation method for cell culture media. Anisotropy provides emission resolution between large and small fluorophores while TSFS provides a robust measurement space. Model cell culture media was prepared using yeastolate (2.5 mg mL(-1)) spiked with bovine serum albumin (0 to 5 mg mL(-1)). Using this method, protein emission is clearly discriminated from background yeastolate emission, allowing for accurate bovine serum albumin (BSA) quantification over a 0.1 to 4.0 mg mL(-1) range with a limit of detection (LOD) of 13.8 μg mL(-1). Copyright © 2014. Published by Elsevier B.V.

Method for rapid multidiameter single-fiber reflectance and fluorescence spectroscopy through a fiber bundle

NARCIS (Netherlands)

Amelink, A.; Hoy, C.L.; Gamm, U.A.; Sterenborg, H.J.C.M.; Robinson, D.J.

2014-01-01

We have recently demonstrated a means for quantifying the absorption and scattering properties of biological tissue through multidiameter single-fiber reflectance (MDSFR) spectroscopy. These measurements can be used to correct single-fiber fluorescence (SFF) spectra for the influence of optical

Correlation of Improved Version of Cervical Vertebral Maturation Indicator with Other Growth Maturity Indicators

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Tripti Tikku

2013-01-01

Conclusion: The correlation between middle phalanx of 3rd finger (MP3 and cervical vertebral maturation method (CVMI and CVMS was higher as compared to the correlation of either of the cervical vertebral maturation method or MP3 with dental maturation indicator.

Enzyme-Free Detection of Mutations in Cancer DNA Using Synthetic Oligonucleotide Probes and Fluorescence Microscopy

DEFF Research Database (Denmark)

Miotke, Laura; Maity, Arindam; Ji, Hanlee

2015-01-01

BACKGROUND: Rapid reliable diagnostics of DNA mutations are highly desirable in research and clinical assays. Current development in this field goes simultaneously in two directions: 1) high-throughput methods, and 2) portable assays. Non-enzymatic approaches are attractive for both types...... 1000-fold above the potential detection limit. CONCLUSION: Overall, the novel assay we describe could become a new approach to rapid, reliable and enzyme-free diagnostics of cancer or other associated DNA targets. Importantly, stoichiometry of wild type and mutant targets is conserved in our assay...... of methods since they would allow rapid and relatively inexpensive detection of nucleic acids. Modern fluorescence microscopy is having a huge impact on detection of biomolecules at previously unachievable resolution. However, no straightforward methods to detect DNA in a non-enzymatic way using fluorescence...

Highly sensitive rapid fluorescence detection of protein residues on surgical instruments

International Nuclear Information System (INIS)

Kovalev, Valeri I; Bartona, James S; Richardson, Patricia R; Jones, Anita C

2006-01-01

There is a risk of contamination of surgical instruments by infectious protein residues, in particular, prions which are the agents for Creutzfeldt-Jakob Disease in humans. They are exceptionally resistant to conventional sterilization, therefore it is important to detect their presence as contaminants so that alternative cleaning procedures can be applied. We describe the development of an optimized detection system for fluorescently labelled protein, suitable for in-hospital use. We show that under optimum conditions the technique can detect ∼10 attomole/cm 2 with a scan speed of ∼3-10 cm 2 /s of the test instrument's surface. A theoretical analysis and experimental measurements will be discussed

Rapid analysis of molybdenum contents in molybdenum master alloys by X-ray fluorescence technique

International Nuclear Information System (INIS)

Tongkong, P.

1985-01-01

Determination of molybdenum contents in molybdenum master alloy had been performed using energy dispersive x-ray fluorescence (EDX) technique where analysis were made via standard additions and calibration curves. Comparison of EDX technique with other analyzing techniques, i.e., wavelength dispersive x-ray fluorescence, neutron activation analysis and inductive coupled plasma spectrometry, showed consistency in the results. This technique was found to yield reliable results when molybdenum contents in master alloys were in the range of 13 to 50 percent using HPGe detector or proportional counter. When the required error was set at 1%, the minimum analyzing time was found to be 30 and 60 seconds for Fe-Mo master alloys with molybdenum content of 13.54 and 49.09 percent respectively. For Al-Mo master alloys, the minimum times required were 120 and 300 seconds with molybdenum content of 15.22 and 47.26 percent respectively

Developing maturity grids for assessing organisational capabilities

DEFF Research Database (Denmark)

Maier, Anja; Moultrie, James; Clarkson, P John

2009-01-01

Keyword: Maturity Model,Maturity Grid,Maturity Matrix,Organisational Capabilities,Benchmarking,New Product Development,Perfirmance Assessment......Keyword: Maturity Model,Maturity Grid,Maturity Matrix,Organisational Capabilities,Benchmarking,New Product Development,Perfirmance Assessment...

The use of maturity method in estimating concrete strength

International Nuclear Information System (INIS)

Salama, A.E.; Abd El-Baky, S.M.; Ali, E.E.; Ghanem, G.M.

2005-01-01

Prediction of the early age strength of concrete is essential for modernized concrete for construction as well as for manufacturing of structural parts. Safe and economic scheduling of such critical operations as form removal and re shoring, application of post-tensioning or other mechanical treatment, and in process transportation and rapid delivery of products all should be based upon a good grasp of the strength development of the concrete in use. For many years, it has been proposed that the strength of concrete can be related to a simple mathematical function of time and temperature so that strength could be assessed by calculation without mechanical testing. Such functions are used to compute what is called the m aturity o f concrete, and the computed value is believed to obtain a correlation with the strength of concrete. With its simplicity and low cost, the application of maturity concept as in situ testing method has received wide attention and found its use in engineering practice. This research work investigates the use of M aturity method' in estimating the concrete strength. An experimental program is designed to estimate the concrete strength by using the maturity method. Using different concrete mixes, with available local materials. Ordinary Portland Cement, crushed stone, silica fume, fly ash and admixtures with different contents are used . All the specimens were exposed to different curing temperatures (10, 25 and 40 degree C), in order to get a simplified expression of maturity that fits in with the influence of temperature. Mix designs and charts obtained from this research can be used as guide information for estimating concrete strength by using the maturity method

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

Directory of Open Access Journals (Sweden)

WANG Yuanfeng

2014-12-01

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

Multicolor fluorescent biosensor for multiplexed detection of DNA.

Science.gov (United States)

Hu, Rong; Liu, Tao; Zhang, Xiao-Bing; Huan, Shuang-Yan; Wu, Cuichen; Fu, Ting; Tan, Weihong

2014-05-20

Development of efficient methods for highly sensitive and rapid screening of specific oligonucleotide sequences is essential to the early diagnosis of serious diseases. In this work, an aggregated cationic perylene diimide (PDI) derivative was found to efficiently quench the fluorescence emission of a variety of anionic oligonucleotide-labeled fluorophores that emit at wavelengths from the visible to NIR region. This broad-spectrum quencher was then adopted to develop a multicolor biosensor via a label-free approach for multiplexed fluorescent detection of DNA. The aggregated perylene derivative exhibits a very high quenching efficiency on all ssDNA-labeled dyes associated with biosensor detection, having efficiency values of 98.3 ± 0.9%, 97 ± 1.1%, and 98.2 ± 0.6% for FAM, TAMRA, and Cy5, respectively. An exonuclease-assisted autocatalytic target recycling amplification was also integrated into the sensing system. High quenching efficiency combined with autocatalytic target recycling amplification afforded the biosensor with high sensitivity toward target DNA, resulting in a detection limit of 20 pM, which is about 50-fold lower than that of traditional unamplified homogeneous fluorescent assay methods. The quencher did not interfere with the catalytic activity of nuclease, and the biosensor could be manipulated in either preaddition or postaddition manner with similar sensitivity. Moreover, the proposed sensing system allows for simultaneous and multicolor analysis of several oligonucleotides in homogeneous solution, demonstrating its potential application in the rapid screening of multiple biotargets.

People Capability Maturity Model. SM.

Science.gov (United States)

1995-09-01

tailored so it consumes less time and resources than a traditional software process assessment or CMU/SEI-95-MM-02 People Capability Maturity Model...improved reputation or customer loyalty. CMU/SEI-95-MM-02 People Capability Maturity Model ■ L5-17 Coaching Level 5: Optimizing Activity 1...Maturity Model CMU/SEI-95-MM-62 Carnegie-Mellon University Software Engineering Institute DTIC ELECTE OCT 2 7 1995 People Capability Maturity

Fluorescent Silica Nanoparticles in the Detection and Control of the Growth of Pathogen

International Nuclear Information System (INIS)

Chitra, K.; Annadurai, G.

2013-01-01

In this present study the bio conjugated fluorescent silica nanoparticles give an efficient fluorescent-based immunoassay for the detection of pathogen. The synthesized silica nanoparticles were poly dispersed and the size of the silica nanoparticles was in the range of 114-164 nm. The energy dispersive X-ray spectrophotometer showed the presence of silica at 1.8 keV and the selected area diffractometer showed amorphous nature of silica nanoparticles. The FTIR spectrum confirmed the attachment of dye and carboxyl group onto the silica nanoparticles surface. The fluorescent silica nanoparticles showed highly efficient fluorescence and the fluorescent emission of silica nanoparticles occurred at 536 nm. The SEM image showed the aggregation of nanoparticles and bacteria. The growth of the pathogenic E. coli was controlled using silica nanoparticles; therefore silica nanoparticles could be used in food packaging material, biomedical material, and so forth. This work provides a rapid, simple, and accurate method for the detection of pathogen using fluorescent-based immunoassay.

Diagnostic imaging of cervical intraepithelial neoplasia based on hematoxylin and eosin fluorescence.

Science.gov (United States)

Castellanos, Mario R; Szerszen, Anita; Gundry, Stephen; Pirog, Edyta C; Maiman, Mitchell; Rajupet, Sritha; Gomez, John Paul; Davidov, Adi; Debata, Priya Ranjan; Banerjee, Probal; Fata, Jimmie E

2015-07-25

Pathological classification of cervical intraepithelial neoplasia (CIN) is problematic as it relies on subjective criteria. We developed an imaging method that uses spectroscopy to assess the fluorescent intensity of cervical biopsies derived directly from hematoxylin and eosin (H&E) stained tissues. Archived H&E slides were identified containing normal cervical tissue, CIN I, and CIN III cases, from a Community Hospital and an Academic Medical Center. Cases were obtained by consensus review of at least 2 senior pathologists. Images from H&E slides were captured first with bright field illumination and then with fluorescent illumination. We used a Zeiss Axio Observer Z1 microscope and an AxioVision 4.6.3-AP1 camera at excitation wavelength of 450-490 nm with emission captured at 515-565 nm. The 32-bit grayscale fluorescence images were used for image analysis. We reviewed 108 slides: 46 normal, 33 CIN I and 29 CIN III. Fluorescent intensity increased progressively in normal epithelial tissue as cells matured and advanced from the basal to superficial regions of the epithelium. In CIN I cases this change was less prominent as compared to normal. In high grade CIN lesions, there was a slight or no increase in fluorescent intensity. All groups examined were statistically different. Presently, there are no markers to help in classification of CIN I-III lesions. Our imaging method may complement standard H&E pathological review and provide objective criteria to support the CIN diagnosis.

One-pot synthesis of gold nanoclusters with bright red fluorescence and good biorecognition abilities for visualization fluorescence enhancement detection of E. coli.

Science.gov (United States)

Liu, Jiali; Lu, Lili; Xu, Suying; Wang, Leyu

2015-03-01

A facile one-pot strategy was developed for the synthesis of lysozyme functionalized fluorescence gold nanoclusters (AuNCs). The lysozymes added to reduce Au(3+) ions and stabilize the AuNCs during the synthesis were coated on the AuNCs surface and retained their specific recognition ability for bacteria such as Escherichia coli (E. coli). Based on such ability, these AuNCs were specifically attached onto the surface of E. coli, which resulted in great red fluorescence enhancement. Nevertheless, the bovine serum albumin (BSA) stabilized AuNCs could not recognize E. coli and no fluorescence enhancement was observed. Upon the addition of E. coli, the red fluorescence intensity of lysozyme-AuNCs was enhanced linearly over the range of 2.4×10(4) -6.0×10(6) CFU/mL of E. coli with high sensitivity (LOD=2.0×10(4) CFU/mL, S/N=3). The visualization fluorescence evolution may enable the rapid and real-time detection of bacteria. This study may be extended to other functional proteins such as antibody, enzyme, and peptide functionalized nanoclusters while retaining the bioactivity of coating proteins and find wide applications in the fields of biochemistry and biomedicine. Copyright © 2014 Elsevier B.V. All rights reserved.

Continuous-Flow Detector for Rapid Pathogen Identification

Energy Technology Data Exchange (ETDEWEB)

Barrett, Louise M. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics; Skulan, Andrew J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics; Singh, Anup K. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics; Cummings, Eric B. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics; Fiechtner, Gregory J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics

2006-09-01

This report describes the continued development of a low-power, portable detector for the rapid identification of pathogens such as B. anthracis and smallpox. Based on our successful demonstration of the continuous filter/concentrator inlet, we believe strongly that the inlet section will enable differentiation between viable and non-viable populations, between types of cells, and between pathogens and background contamination. Selective, continuous focusing of particles in a microstream enables highly selective and sensitive identification using fluorescently labeled antibodies and other receptors such as peptides, aptamers, or small ligands to minimize false positives. Processes such as mixing and lysing will also benefit from the highly localized particle streams. The concentrator is based on faceted prisms to contract microfluidic flows while maintaining uniform flowfields. The resulting interfaces, capable of high throughput, serve as high-, low-, and band-pass filters to direct selected bioparticles to a rapid, affinity-based detection system. The proposed device is superior to existing array-based detectors as antibody-pathogen binding can be accomplished in seconds rather than tens of minutes or even hours. The system is being designed to interface with aerosol collectors under development by the National Laboratories or commercial systems. The focused stream is designed to be interrogated using diode lasers to differentiate pathogens by light scattering. Identification of particles is done using fluorescently labeled antibodies to tag the particles, followed by multiplexed laser-induced fluorescence (LIF) detection (achieved by labeling each antibody with a different dye).

Measurement of the fluorescence of crop residues: A tool for controlling soil erosion

Science.gov (United States)

Daughtry, C. S. T.; Mcmurtrey, J. E., III; Chappelle, E. W.; Hunter, W. J.

1994-01-01

Management of crop residues, the portion of a crop left in the field after harvest, is an important conservation practice for minimizing soil erosion and for improving water quality. Quantification of crop residue cover is required to evaluate the effectiveness of conservation tillage practices. Methods are needed to quantify residue cover that are rapid, accurate, and objective. The fluorescence of crop residue was found to be a broadband phenomenon with emission maxima at 420 to 495 nm for excitations of 350 to 420 nm. Soils had low intensity broadband emissions over the 400 to 690 nm region for excitations of 300 to 600 nm. The range of relative fluorescence intensities for the crop residues was much greater than the fluorescence observed of the soils. As the crop residues decompose their blue fluorescence values approach the fluorescence of the soil. Fluorescence techniques are concluded to be less ambiguous and better suited for discriminating crop residues and soils than reflectance methods. If properly implemented, fluorescence techniques can be used to quantify, not only crop residue cover, but also photosynthetic efficiency in the field.

IT Governance Maturity: Developing a Maturity Model Using the Delphi Method

NARCIS (Netherlands)

Smits, Daniël; van Hillegersberg, Jos

2015-01-01

To advance in maturity, organizations should pay attention to both the hard and soft sides of IT governance (ITG). The hard side is related to processes and structure, the soft side to social aspects like behavior and organizational culture. This paper describes a study to develop an ITG maturity

Determination of rare-earth elements in rocks by isotope-excited X-ray fluorescence spectrometry

DEFF Research Database (Denmark)

Kunzendorf, Helmar; Wollenberg, H.A.

1970-01-01

Isotope-excited X-ray fluorescence spectrometry furnishes a rapid determination of rare-earth elements in unprepared rock samples. The samples are excited by 241Am γ-rays, generating X-ray spectra on a multichannel pulse-height analyser. Gaussian peaks of the Kα and Kβ X-ray energies are treated ......-ray spectrometric scan of a longitudinally sliced drill core showed a close correlation between rare-earth abundances and appropriate minerals.......Isotope-excited X-ray fluorescence spectrometry furnishes a rapid determination of rare-earth elements in unprepared rock samples. The samples are excited by 241Am γ-rays, generating X-ray spectra on a multichannel pulse-height analyser. Gaussian peaks of the Kα and Kβ X-ray energies are treated...

Fluoromycobacteriophages for Rapid, Specific, and Sensitive Antibiotic Susceptibility Testing of Mycobacterium tuberculosis

Science.gov (United States)

Piuri, Mariana; Jacobs, William R.; Hatfull, Graham F.

2009-01-01

Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis is of paramount importance as multiple- and extensively- drug resistant strains of M. tuberculosis emerge and spread. We describe here a virus-based assay in which fluoromycobacteriophages are used to deliver a GFP or ZsYellow fluorescent marker gene to M. tuberculosis, which can then be monitored by fluorescent detection approaches including fluorescent microscopy and flow cytometry. Pre-clinical evaluations show that addition of either Rifampicin or Streptomycin at the time of phage addition obliterates fluorescence in susceptible cells but not in isogenic resistant bacteria enabling drug sensitivity determination in less than 24 hours. Detection requires no substrate addition, fewer than 100 cells can be identified, and resistant bacteria can be detected within mixed populations. Fluorescence withstands fixation by paraformaldehyde providing enhanced biosafety for testing MDR-TB and XDR-TB infections. PMID:19300517

Nonmydriatic fluorescence-based quantitative imaging of human macular pigment distributions

Science.gov (United States)

Sharifzadeh, Mohsen; Bernstein, Paul S.; Gellermann, Werner

2006-10-01

We have developed a CCD-camera-based nonmydriatic instrument that detects fluorescence from retinal lipofuscin chromophores ("autofluorescence") as a means to indirectly quantify and spatially image the distribution of macular pigment (MP). The lipofuscin fluorescence intensity is reduced at all retinal locations containing MP, since MP has a competing absorption in the blue-green wavelength region. Projecting a large diameter, 488 nm excitation spot onto the retina, centered on the fovea, but extending into the macular periphery, and comparing lipofuscin fluorescence intensities outside and inside the foveal area, it is possible to spatially map out the distribution of MP. Spectrally selective detection of the lipofuscin fluorescence reveals an important wavelength dependence of the obtainable image contrast and deduced MP optical density levels, showing that it is important to block out interfering fluorescence contributions in the detection setup originating from ocular media such as the lens. Measuring 70 healthy human volunteer subjects with no ocular pathologies, we find widely varying spatial extent of MP, distinctly differing distribution patterns of MP, and strongly differing absolute MP levels among individuals. Our population study suggests that MP imaging based on lipofuscin fluorescence is useful as a relatively simple, objective, and quantitative noninvasive optical technique suitable to rapidly screen MP levels and distributions in healthy humans with undilated pupils.

Highly sensitive rapid fluorescence detection of protein residues on surgical instruments

Energy Technology Data Exchange (ETDEWEB)

Kovalev, Valeri I [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Bartona, James S [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Richardson, Patricia R [School of Chemistry, University of Edinburgh, Edinburgh, EH9 3JJ (United Kingdom); Jones, Anita C [School of Chemistry, University of Edinburgh, Edinburgh, EH9 3JJ (United Kingdom)

2006-07-15

There is a risk of contamination of surgical instruments by infectious protein residues, in particular, prions which are the agents for Creutzfeldt-Jakob Disease in humans. They are exceptionally resistant to conventional sterilization, therefore it is important to detect their presence as contaminants so that alternative cleaning procedures can be applied. We describe the development of an optimized detection system for fluorescently labelled protein, suitable for in-hospital use. We show that under optimum conditions the technique can detect {approx}10 attomole/cm{sup 2} with a scan speed of {approx}3-10 cm{sup 2}/s of the test instrument's surface. A theoretical analysis and experimental measurements will be discussed.

MatureBayes: a probabilistic algorithm for identifying the mature miRNA within novel precursors.

Directory of Open Access Journals (Sweden)

Katerina Gkirtzou

Full Text Available BACKGROUND: MicroRNAs (miRNAs are small, single stranded RNAs with a key role in post-transcriptional regulation of thousands of genes across numerous species. While several computational methods are currently available for identifying miRNA genes, accurate prediction of the mature miRNA remains a challenge. Existing approaches fall short in predicting the location of mature miRNAs but also in finding the functional strand(s of miRNA precursors. METHODOLOGY/PRINCIPAL FINDINGS: Here, we present a computational tool that incorporates a Naive Bayes classifier to identify mature miRNA candidates based on sequence and secondary structure information of their miRNA precursors. We take into account both positive (true mature miRNAs and negative (same-size non-mature miRNA sequences examples to optimize sensitivity as well as specificity. Our method can accurately predict the start position of experimentally verified mature miRNAs for both human and mouse, achieving a significantly larger (often double performance accuracy compared with two existing methods. Moreover, the method exhibits a very high generalization performance on miRNAs from two other organisms. More importantly, our method provides direct evidence about the features of miRNA precursors which may determine the location of the mature miRNA. We find that the triplet of positions 7, 8 and 9 from the mature miRNA end towards the closest hairpin have the largest discriminatory power, are relatively conserved in terms of sequence composition (mostly contain a Uracil and are located within or in very close proximity to the hairpin loop, suggesting the existence of a possible recognition site for Dicer and associated proteins. CONCLUSIONS: This work describes a novel algorithm for identifying the start position of mature miRNA(s produced by miRNA precursors. Our tool has significantly better (often double performance than two existing approaches and provides new insights about the potential use

Rapid tracking of metals and other minerals in solid contaminated environments matters (soil, waste) thanks to non-destructive and rapid on-site methods with x-fluorescence. Extended abstract

International Nuclear Information System (INIS)

Bouzonville, A.; Colin, A.; Durin, L.; Gruffat, V.; Chassagnac, T.

2008-05-01

Rapid tracking of metals and other minerals in solid contaminated environments matters greatly to the various firms working in waste disposal. In order to facilitate decision-making that rely on non-destructive and rapid onsite methods of analysis, a review of such methods has been carried out though Scientific publications and Technical reports. Only X-fluorescence is presented as suitable, albeit with some limitations. In order to check the collected bibliographical data and to test both the limits and the limitations imposed by the use of portable XRF instruments, several series of experiments were conducted using two types of portable instruments: a gun-like instrument and a portable-class instrument. With the help of such instruments, the experiments were mainly oriented towards applications that are neglected in field research with regards to waste materials such as: - bulky curbside refuse, - contaminated land, - sludge from the dredging of ports and rivers, - steelwork slurries and dust particles. As these instruments make it possible to obtain samples before analysis, more in-depth evaluation of this aspect is relevant. Thus the number of samples to be analyzed, the kind of conditioning (grinding, sifting), the moisture, are parameters that require evaluation for each individual case and each different type of waste matter. Such aspect can be especially iffy when heterogeneous waste matter like recycling refuse is handled. In fact, the precision of the instruments usually do not cover the regulation thresholds or the techniques that are require by users. It is therefore necessary for the users of these instruments to be aware of the utilization limits and to develop protocols that are suitable for each situation, in order to get readings that are representative and can be interpreted. (authors)

Academic Achievement of High School Students in Relation to Their Anxiety, Emotional Maturity and Social Maturity

Science.gov (United States)

Puar, Surjit Singh

2013-01-01

The present study has been designed to investigate the non-cognitive variables like anxiety, emotional maturity and social maturity and their relationship with academic achievement and also to see the locale-wise differences on the basis of their anxiety, emotional maturity and social maturity. The study was conducted over a sample of 400 (200…

Leveraging People-Related Maturity Issues for Achieving Higher Maturity and Capability Levels

Science.gov (United States)

Buglione, Luigi

During the past 20 years Maturity Models (MM) become a buzzword in the ICT world. Since the initial Crosby's idea in 1979, plenty of models have been created in the Software & Systems Engineering domains, addressing various perspectives. By analyzing the content of the Process Reference Models (PRM) in many of them, it can be noticed that people-related issues have little weight in the appraisals of the capabilities of organizations while in practice they are considered as significant contributors in traditional process and organizational performance appraisals, as stressed instead in well-known Performance Management models such as MBQA, EFQM and BSC. This paper proposes some ways for leveraging people-related maturity issues merging HR practices from several types of maturity models into the organizational Business Process Model (BPM) in order to achieve higher organizational maturity and capability levels.

In-vivo cancer diagnosis of the esophagus using laser-induced fluorescence

Science.gov (United States)

Vo-Dinh, Tuan; Panjehpour, Masoud; Overholt, Bergein F.; Buckley, Paul F., II; Edwards, Donna H.

1995-04-01

Laser-induced fluorescence (LIF) was used for direct in-vivo cancer diagnosis of the esophagus without requiring biopsy. The methodology was applied to differentiate normal and malignant tumors of the esophagus. Endogenous fluorescence of normal and malignant tissues were measured directly using a fiberoptic probe inserted through an endoscope. The measurements were performed in vivo during routine endoscopy. Detection of the fluorescence signal from the tissue was performed using laser excitation. The results of this LIF approach were compared with histopathology results of the biopsy samples and indicated excellent agreement in the classification of normal and malignant tumors for the samples investigated. The LIF procedure could lead to the development of a rapid and cost-effective technique for cancer diagnosis.

Fluorescent SiC with pseudo-periodic moth-eye structures

DEFF Research Database (Denmark)

Ou, Yiyu; Aijaz, Imran; Ou, Haiyan

2012-01-01

White light-emitting diodes (LEDs) consisting of a nitride-based blue LED chip and phosphor are very promising candidates for the general lighting applications as energy-saving sources. Recently, donor-acceptor doped fluorescent SiC has been proven as a highly efficient wavelength converter...... to enhance the extraction efficiency, we present a simple method to fabricate the pseudo-periodic moth-eye structures on the surface of the fluorescent SiC. A thin gold layer is deposited on the fluorescent SiC first. Then the thin gold layer is treated by rapid thermal processing. After annealing, the thin...... gold layer turns into discontinuous nano-islands. The average size of the islands is dependent on the annealing condition which could be well controlled. By using the reactive-ion etching, pseudo-periodic moth-eye structures would be obtained using the gold nano-islands as a mask layer. Reactive...

Whole-slide imaging is a robust alternative to traditional fluorescent microscopy for fluorescence in situ hybridization imaging using break-apart DNA probes.

Science.gov (United States)

Laurent, Camille; Guérin, Maxime; Frenois, François-Xavier; Thuries, Valérie; Jalabert, Laurence; Brousset, Pierre; Valmary-Degano, Séverine

2013-08-01

Fluorescence in situ hybridization is an indispensable technique used in routine pathology and for theranostic purposes. Because fluorescence in situ hybridization techniques require sophisticated microscopic workstations and long procedures of image acquisition with sometimes subjective and poorly reproducible results, we decided to test a whole-slide imaging system as an alternative approach. In this study, we used the latest generation of Pannoramic 250 Flash digital microscopes (P250 Flash digital microscopes; 3DHISTECH, Budapest, Hungary) to digitize fluorescence in situ hybridization slides of diffuse large B cells lymphoma cases for detecting MYC rearrangement. The P250 Flash digital microscope was found to be precise with better definition of split signals in cells containing MYC rearrangement with fewer truncated signals as compared to traditional fluorescence microscopy. This digital technique is easier thanks to the preview function, which allows almost immediate identification of the tumor area, and the panning and zooming functionalities as well as a shorter acquisition time. Moreover, fluorescence in situ hybridization analyses using the digital technique appeared to be more reproducible between pathologists. Finally, the digital technique also allowed prolonged conservation of photos. In conclusion, whole-slide imaging technologies represent rapid, robust, and highly sensitive methods for interpreting fluorescence in situ hybridization slides with break-apart probes. In addition, these techniques offer an easier way to interpret the signals and allow definitive storage of the images for pathology expert networks or e-learning databases. Copyright © 2013 Elsevier Inc. All rights reserved.

Fluorescent IgG fusion proteins made in E. coli

Science.gov (United States)

Luria, Yael; Raichlin, Dina; Benhar, Itai

2012-01-01

Antibodies are among the most powerful tools in biological and biomedical research and are presently the fastest growing category of new bio-pharmaceutics. The most common format of antibody applied for therapeutic, diagnostic and analytical purposes is the IgG format. For medical applications, recombinant IgGs are made in cultured mammalian cells in a process that is too expensive to be considered for producing antibodies for diagnostic and analytical purposes. Therefore, for such purposes, mouse monoclonal antibodies or polyclonal sera from immunized animals are used. While looking for an easier and more rapid way to prepare full-length IgGs for therapeutic purposes, we recently developed and reported an expression and purification protocol for full-length IgGs, and IgG-based fusion proteins in E. coli, called “Inclonals.” By applying the Inclonals technology, we could generate full-length IgGs that are genetically fused to toxins. The aim of the study described herein was to evaluate the possibility of applying the “Inclonals” technology for preparing IgG-fluorophore fusion proteins. We found that IgG fused to the green fluorescent proteins enhanced GFP (EGFP) while maintaining functionality in binding, lost most of its fluorescence during the refolding process. In contrast, we found that green fluorescent Superfolder GFP (SFGFP)-fused IgG and red fluorescent mCherry-fused IgG were functional in antigen binding and maintained fluorescence intensity. In addition, we found that we can link several SFGFPs in tandem to each IgG, with fluorescence intensity increasing accordingly. Fluorescent IgGs made in E. coli may become attractive alternatives to monoclonal or polyclonal fluorescent antibodies derived from animals. PMID:22531449

Cracking and thermal maturity of Ordovician oils from Tahe Oilfield, Tarim Basin, NW China

Directory of Open Access Journals (Sweden)

Anlai Ma

2017-12-01

Full Text Available The thermal maturity of the Ordovician oils from the Tahe oilfield of Tarim Basin, NW China was assessed through various maturity parameters, such as biomarkers, aromatic parameters, and diamondoid parameters. Both Ts/(Ts+Tm and C29Ts/(C29H+C29Ts values indicate that the maturity of oils has not reached the condensates stage, which is consistent with the maturity obtained by MPI1. However, the diamondoid maturity suggests that the oil maturity ranges 1.1%–1.6% Ro, which is apparently higher than that of the maturity obtained by the biomarker and MPI1. This discrepancy in maturity may indicate that the Ordovician reservoir has multiple filling history. The 4-MD+3-MD concentration of oils disperses and increases slowly when the Ts/(Ts+Tm value is lower than 0.55. Meanwhile, the value increases rapidly when the Ts/(Ts+Tm value is higher than 0.55. It is proposed that the diamondoid baseline is about 15 μg/goil for marine oils in the Tahe oilfield based on the diamondoid concentration of marine oils from reservoirs of various age. The concentration of 4-MD+3-MD of most Ordovician oils generally ranges from 4.5 to 35 μg/goil, suggesting that the degree of oil-cracking is lower than 50% and the deep Ordovician have potential of oil exploration. The distribution of the concentration of 4-MD+3-MD is characterized by being high in the east and south, low in the west and north, proposing that the two migration pathways exit in the oilfield, which are from east to west and from south to north, respectively. The migration directions are consistent with the results obtained from the oil density and the maturity parameters such as Ts/(Ts+Tm. Thus, suggesting the concentration of 4-MD+3-MD can be used as migration index in oilfield scale.

Measurement of protein-like fluorescence in river and waste water using a handheld spectrophotometer.

Science.gov (United States)

Baker, Andy; Ward, David; Lieten, Shakti H; Periera, Ryan; Simpson, Ellie C; Slater, Malcolm

2004-07-01

Protein-like fluorescence intensity in rivers increases with increasing anthropogenic DOM inputs from sewerage and farm wastes. Here, a portable luminescence spectrophotometer was used to investigate if this technology could be used to provide both field scientists with a rapid pollution monitoring tool and process control engineers with a portable waste water monitoring device, through the measurement of river and waste water tryptophan-like fluorescence from a range of rivers in NE England and from effluents from within two waste water treatment plants. The portable spectrophotometer determined that waste waters and sewerage effluents had the highest tryptophan-like fluorescence intensity, urban streams had an intermediate tryptophan-like fluorescence intensity, and the upstream river samples of good water quality the lowest tryptophan-like fluorescence intensity. Replicate samples demonstrated that fluorescence intensity is reproducible to +/- 20% for low fluorescence, 'clean' river water samples and +/- 5% for urban water and waste waters. Correlations between fluorescence measured by the portable spectrophotometer with a conventional bench machine were 0.91; (Spearman's rho, n = 143), demonstrating that the portable spectrophotometer does correlate with tryptophan-like fluorescence intensity measured using the bench spectrophotometer.

Maturity Models Development in IS Research

DEFF Research Database (Denmark)

Lasrado, Lester Allan; Vatrapu, Ravi; Andersen, Kim Normann

2015-01-01

Maturity models are widespread in IS research and in particular, IT practitioner communities. However, theoretically sound, methodologically rigorous and empirically validated maturity models are quite rare. This literature review paper focuses on the challenges faced during the development...... literature reveals that researchers have primarily focused on developing new maturity models pertaining to domain-specific problems and/or new enterprise technologies. We find rampant re-use of the design structure of widely adopted models such as Nolan’s Stage of Growth Model, Crosby’s Grid, and Capability...... Maturity Model (CMM). Only recently have there been some research efforts to standardize maturity model development. We also identify three dominant views of maturity models and provide guidelines for various approaches of constructing maturity models with a standard vocabulary. We finally propose using...

Rapid molecular cytogenetic analysis of X-chromosomal microdeletions: Fluorescence in situ hybridization (FISH) for complex glycerol kinase deficiency

Energy Technology Data Exchange (ETDEWEB)

Worley, K.C.; Lindsay, E.A.; McCabe, E.R.B. [Baylor College of Medicine, Houston, TX (United States)] [and others

1995-07-17

Diagnosis of X-chromosomal microdeletions has relied upon the traditional methods of Southern blotting and DNA amplification, with carrier identification requiring time-consuming and unreliable dosage calculations. In this report, we describe rapid molecular cytogenetic identification of deleted DNA in affected males with the Xp21 contiguous gene syndrome (complex glycerol kinase deficiency, CGKD) and female carriers for this disorder. CGKD deletions involve the genes for glycerol kinase, Duchenne muscular dystrophy, and/or adrenal hypoplasia congenita. We report an improved method for diagnosis of deletions in individuals with CGKD and for identification of female carriers within their families using fluorescence in situ hybridization (FISH) with a cosmid marker (cosmid 35) within the glycerol kinase gene. When used in combination with an Xq control probe, affected males demonstrate a single signal from the control probe, while female carriers demonstrate a normal chromosome with two signals, as well as a deleted chromosome with a single signal from the control probe. FISH analysis for CGKD provides the advantages of speed and accuracy for evaluation of submicroscopic X-chromosome deletions, particularly in identification of female carriers. In addition to improving carrier evaluation, FISH will make prenatal diagnosis of CGKD more readily available. 17 refs., 2 figs.

Kerosene detection using laser induced fluorescence imaging for aeronautical engines application; Detection du kerozene par imagerie de fluorescence induite par laser, pour application sur foyer aeronautique

Energy Technology Data Exchange (ETDEWEB)

Baranger, Ph.

2004-10-15

The new concepts of aeronautical engines, developed to follow the evolution of the European standards of pollution, are generally based on an improvement of the processes of liquid fuel injection and mixture in the combustion chamber. There is currently no model mature enough to work without experimental validation. The purpose of this thesis is to assess the possibility of measuring the kerosene (Jet A1) vapour distribution by PLIF (Planar Laser Induced Fluorescence). That measurement technique must quantitatively image the instantaneous concentrations fields of the vaporized fuel in a spray. The implementation of such a technique needs an experimental spectroscopic study, which was realized on the vapour of fuel. First of all, this study allowed us to determine the properties of the kerosene fluorescence spectrum versus physical parameters such as temperature, pressure or gas mixture composition, especially in presence of oxygen molecules. Then, it was shown that the fluorescence spectrum of the fuel could be reproduce in all physical conditions by a single mixture of four aromatics. Their photophysical properties were also analyzed. Following this spectroscopic study, a phenomenological model for the fluorescence of the gaseous fuel was set up. This model led us to a protocol for an optical diagnostic on this fuel vapour. An experiment was set up to test the implementation and the limits of this technique in simple laboratory conditions. This experiment confirmed that this is indeed a promising technique for the diagnostic of the fuel vapour in aeronautical engine. (author)

Simultaneous determination of glycols based on fluorescence anisotropy

International Nuclear Information System (INIS)

Garcia Sanchez, F.; Navas Diaz, A.; Lopez Guerrero, M.M.

2007-01-01

Simultaneous determination of non-fluorescent glycols in mixtures without separation or chemical transformation steps is described. Two methods based in the measure of fluorescence anisotropy of a probe such as fluorescein dissolved in the analyte or analyte mixtures are described. In the first method, the anisotropy spectra of pure and mixtures of analytes are used to quantitative determination (if the fluorophor concentration is in a range where fluorescence intensity is proportional to concentration). In the second method, a calibration curve anisotropy-concentration based on the application of the Perrin equation is established. The methods presented here are capable of directly resolving binary mixtures of non-fluorescent glycols on the basis of differences on the fluorescence anisotropy of a fluorescence tracer. Best analytical performances were obtained by application of the method based on Perrin equation. This method is simple, rapid and allows the determination of mixtures of glycols with reasonable accuracy and precision. Detection limits are limited by the quantum yield and anisotropy values of the tracer in the solvents. Recovery values are related to the differences in anisotropy values of the tracer in the pure solvents. Mixtures of glycerine/ethylene glycol (GL/EG), ethylene glycol/1,2-propane diol (EG/1,2-PPD) and polyethylene glycol 400/1,2-propane diol (PEG 400/1,2-PPD) were analysed and recovery values are within 95-120% in the Perrin method. Relative standard deviation are in the range 1.3-2.9% and detection limits in the range 3.9-8.9%

Modeling non-maturing liabilities

OpenAIRE

von Feilitzen, Helena

2011-01-01

Non‐maturing liabilities, such as savings accounts, lack both predetermined maturity and reset dates due to the fact that the depositor is free to withdraw funds at any time and that the depository institution is free to change the rate. These attributes complicate the risk management of such products and no standardized solution exists. The problem is important however since non‐maturing liabilities typically make up a considerable part of the funding of a bank. In this report different mode...

Cortical bone growth and maturational changes in dwarf rats induced by recombinant human growth hormone

Science.gov (United States)

Martinez, D. A.; Orth, M. W.; Carr, K. E.; Vanderby, R. Jr; Vailas, A. C.

1996-01-01

The growth hormone (GH)-deficient dwarf rat was used to investigate recombinant human (rh) GH-induced bone formation and to determine whether rhGH facilitates simultaneous increases in bone formation and bone maturation during rapid growth. Twenty dwarf rats, 37 days of age, were randomly assigned to dwarf plus rhGH (GH; n = 10) and dwarf plus vehicle (n = 10) groups. The GH group received 1.25 mg rhGH/kg body wt two times daily for 14 days. Biochemical, morphological, and X-ray diffraction measurements were performed on the femur middiaphysis. rhGH stimulated new bone growth in the GH group, as demonstrated by significant increases (P bone length (6%), middiaphyseal cross-sectional area (20%), and the amount of newly accreted bone collagen (28%) in the total pool of middiaphyseal bone collagen. Cortical bone density, mean hydroxyapatite crystal size, and the calcium and collagen contents (microgram/mm3) were significantly smaller in the GH group (P bone collagen maturation, and mean hydroxyapatite crystal size may be independently regulated during rapid growth.

Split green fluorescent protein as a modular binding partner for protein crystallization

International Nuclear Information System (INIS)

Nguyen, Hau B.; Hung, Li-Wei; Yeates, Todd O.; Terwilliger, Thomas C.; Waldo, Geoffrey S.

2013-01-01

A strategy using a new split green fluorescent protein (GFP) as a modular binding partner to form stable protein complexes with a target protein is presented. The modular split GFP may open the way to rapidly creating crystallization variants. A modular strategy for protein crystallization using split green fluorescent protein (GFP) as a crystallization partner is demonstrated. Insertion of a hairpin containing GFP β-strands 10 and 11 into a surface loop of a target protein provides two chain crossings between the target and the reconstituted GFP compared with the single connection afforded by terminal GFP fusions. This strategy was tested by inserting this hairpin into a loop of another fluorescent protein, sfCherry. The crystal structure of the sfCherry-GFP(10–11) hairpin in complex with GFP(1–9) was determined at a resolution of 2.6 Å. Analysis of the complex shows that the reconstituted GFP is attached to the target protein (sfCherry) in a structurally ordered way. This work opens the way to rapidly creating crystallization variants by reconstituting a target protein bearing the GFP(10–11) hairpin with a variety of GFP(1–9) mutants engineered for favorable crystallization

A BODIPY-Based Fluorescent Probe to Visually Detect Phosgene: Toward the Development of a Handheld Phosgene Detector.

Science.gov (United States)

Sayar, Melike; Karakuş, Erman; Güner, Tuğrul; Yildiz, Busra; Yildiz, Umit Hakan; Emrullahoğlu, Mustafa

2018-03-02

A boron-dipyrromethene (BODIPY)-based fluorescent probe with a phosgene-specific reactive motif shows remarkable selectivity toward phosgene, in the presence of which the nonfluorescent dye rapidly transforms into a new structure and induces a fluorescent response clearly observable to the naked eye under ultraviolet light. Given that dynamic, a prototypical handheld phosgene detector with a promising sensing capability that expedites the detection of gaseous phosgene without sophisticated instrumentation was developed. The proposed method using the handheld detector involves a rapid response period suitable for issuing early warnings during emergency situations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phosphate regulates chondrogenesis in a biphasic and maturation-dependent manner.

Science.gov (United States)

Wu, Biming; Durisin, Emily K; Decker, Joseph T; Ural, Evran E; Shea, Lonnie D; Coleman, Rhima M

Inorganic phosphate (Pi) has been recognized as an important signaling molecule that modulates chondrocyte maturation and cartilage mineralization. However, conclusive experimental evidence for its involvement in early chondrogenesis is still lacking. Here, using high-density monolayer (2D) and pellet (3D) culture models of chondrogenic ATDC5 cells, we demonstrate that the cell response to Pi does not correlate with the Pi concentration in the culture medium but is better predicted by the availability of Pi on a per cell basis (Pi abundance). Both culture models were treated with ITS+, 10mM β-glycerophosphate (βGP), or ITS+/10mM βGP, which resulted in three levels of Pi abundance in cultures: basal (Pi/DNA 60ng/µg). In chondrogenic medium alone, the abundance levels were at the basal level in 2D culture and moderate in 3D cultures. The addition of 10mM βGP resulted in moderate abundance in 2D and high abundance in 3D cultures. Moderate Pi abundance enhanced early chondrogenesis and production of aggrecan and type II collagen whereas high Pi abundance inhibited chondrogenic differentiation and induced rapid mineralization. Inhibition of sodium phosphate transporters reduced phosphate-induced expression of chondrogenic markers. When 3D ITS+/βGP cultures were treated with levamisole to reduce ALP activity, Pi abundance was decreased to moderate levels, which resulted in significant upregulation of chondrogenic markers, similar to the response in 2D cultures. Delay of phosphate delivery until after early chondrogenesis occurs (7 days) no longer enhanced chondrogenesis, but instead accelerated hypertrophy and mineralization. Together, our data highlights the dependence of chondroprogenitor cell response to Pi on its availability to individual cells and the chondrogenic maturation stage of these cells and suggest that appropriate temporal delivery of phosphate to ATDC5 cells in 3D cultures represents a rapid model for mechanistic studies into the effects of

Slab replacement maturity guidelines.

Science.gov (United States)

2014-04-01

This study investigated the use of maturity method to determine early age strength of concrete in slab : replacement application. Specific objectives were (1) to evaluate effects of various factors on the compressive : maturity-strength relationship ...

Evolution of consumer information preferences with market maturity in solar PV adoption

Science.gov (United States)

Cale Reeves, D.; Rai, Varun; Margolis, Robert

2017-07-01

Residential adoption of solar photovoltaics (PV) is spreading rapidly, supported by policy initiatives at the federal, state, and local levels. Potential adopters navigate increasingly complex decision-making landscapes in their path to adoption. Much is known about the individual-level drivers of solar PV diffusion that steer adopters through this process, but relatively little is known about the evolution of these drivers as solar PV markets mature. By understanding the evolution of emerging solar PV markets over time, stakeholders in the diffusion of solar PV can increase policy effectiveness and reduce costs. This analysis uses survey data to compare two adjacent markets across a range of relevant characteristics, then models changes in the importance of local vs cosmopolitan information sources by combining theory relating market maturity to adopter behavior with event-history techniques. In younger markets, earlier, innovative adoptions that are tied to a preference for cosmopolitan information sources are more prevalent than expected, suggesting a frustrated demand for solar PV that segues into adoptions fueled by local information preferences contemporary with similar adoptions in older markets. The analysis concludes with policy recommendations to leverage changing consumer information preferences as markets mature.

Maturity effects in energy futures

Energy Technology Data Exchange (ETDEWEB)

Serletis, Apostolos (Calgary Univ., AB (CA). Dept. of Economics)

1992-04-01

This paper examines the effects of maturity on future price volatility and trading volume for 129 energy futures contracts recently traded in the NYMEX. The results provide support for the maturity effect hypothesis, that is, energy futures prices to become more volatile and trading volume increases as futures contracts approach maturity. (author).

Correlation between Cervical Vertebral Maturation Stages and Dental Maturation in a Saudi Sample

Directory of Open Access Journals (Sweden)

Nayef H Felemban

2017-01-01

Full Text Available Background: The aim of the present study was to compare the cervical vertebra maturation stages method and dental maturity using tooth calcification stages. Methods: The current study comprised of 405 subjects selected from orthodontic patients of Saudi origin coming to clinics of the specialized dental centers in western region of Saudi Arabia. Dental age was assessed according to the developmental stages of upper and lower third molars and skeletal maturation according to the cervical vertebrae maturation stage method. Statistical analysis was done using Kruskal-Wallis H, Mann-Whitney U test, Chi-Square test; t-test and Spearman correlation coefficient for inter group comparison. Results: The females were younger than males in all cervical stages. The CS1-CS2 show the period before the peak of growth, during CS3-CS5 it’s the pubertal growth spurt and CS6 is the period after the peak of the growth. The mean age and standard deviation for cervical stages of CS2, CS3 and CS4 were 12.09 ±1.72 years, 13.19 ±1.62 and 14.88 ±1.52 respectively. The Spearman correlation coefficients between cervical vertebrae and dental maturation were between 0.166 and 0.612, 0.243 and 0.832 for both sexes for upper and lower third molars. The significance levels for all coefficients were equal at 0.01 and 0.05. Conclusion: The results of this study showed that the skeletal maturity increased with the increase in dental ages for both genders. An early rate of skeletal maturation stage was observed in females. This study needs further analysis using a larger sample covering the entire dentition.

Quenched carbonaceous composite - Fluorescence spectrum compared to the extended red emission observed in reflection nebulae

Science.gov (United States)

Sakata, Akira; Wada, Setsuko; Narisawa, Takatoshi; Asano, Yoichi; Iijima, Yutaka; Onaka, Takashi; Tokunaga, Alan T.

1992-01-01

The photoluminescence (fluorescence) of a film of the laboratory-synthesized quenched carbonaceous composite (filmy QCC) is shown to have a single broad emission feature with a peak wavelength that varies from 670 to 725 nm, and coincides with that of the extended red emission observed in reflection nebulae. The rapid decay of the filmy QCC red fluorescence in air and of the stable blue fluorescence of the filmy QCC dissolved in liquid Freon suggests that the red fluorescence originates from the interaction of active chemical species and aromatic components in the filmy QCC. A material similar in nature to that of the filmy QCC may be a major component of interstellar dust.

Maturity models in supply chain sustainability

DEFF Research Database (Denmark)

Correia, Elisabete; Carvalho, Helena; Azevedo, Susana G.

2017-01-01

A systematic literature review of supply chain maturity models with sustainability concerns is presented. The objective is to give insights into methodological issues related to maturity models, namely the research objectives; the research methods used to develop, validate and test them; the scope...... of maturity levels. The comprehensive review, analysis, and synthesis of the maturity model literature represent an important contribution to the organization of this research area, making possible to clarify some confusion that exists about concepts, approaches and components of maturity models...

Effect of biofilm on fluorescence measurements derived from fast repetition rate fluorometers

Digital Repository Service at National Institute of Oceanography (India)

Patil, J.S.; Saino, T.

primary production per se. FRRF offers rapid, real time and in situ measurements of photosynthetic characteristics of natural assemblages of marine and freshwater phytoplankton populations (eg Moore et al. 2003 & 2005, Kaiblinger & Dokulil 2006, Mino... et al. 2013) as well as on the reef building corals (Lesser & Gorbunov 2001). The basis of FRRF technique is to measure fluorescence transients induced by a rapid train of sub-saturating excitation flashlets, where the intensity, duration, and time...

Hydrangea-like magneto-fluorescent nanoparticles through thiol-inducing assembly

Science.gov (United States)

Chen, Shun; Zhang, Junjun; Song, Shaokun; Xiong, Chuanxi; Dong, Lijie

2017-01-01

Magneto-fluorescent nanoparticles (NPs), recognized as an emerging class of materials, have drawn much attention because of their potential applications. Due to surface functionalization and thiol-metal bonds, a simple method has been put forward for fabricating hydrangea-like magneto-fluorescent Fe3O4-SH@QD NPs, through assembling thiol-modified Fe3O4 NPs with sub-size multi-layer core/shell CdSe/CdS/ZnS QDs. After a refined but controllable silane hydrolysis process, thiol-modified Fe3O4 was fabricated, resulting in Fe3O4-SH@QD NPs with QDs, while preventing the quenching of the QDs. As a result, the core Fe3O4 NPs were 18 nm in diameter, while the scattered CdSe/CdS/ZnS QDs were 7 nm in diameter. The resultant magneto-fluorescent Fe3O4-SH@QD NPs exhibit efficient fluorescence, superparamagnetism at room temperature, and rapid response to the external field, which make them ideal candidates for difunctional probes in MRI and bio-labels, targeting and photodynamic therapy, and cell tracking and separation.

Integration of novel low-cost colorimetric, laser photometric, and visual fluorescent techniques for rapid identification of falsified medicines in resource-poor areas: application to artemether-lumefantrine.

Science.gov (United States)

Green, Michael D; Hostetler, Dana M; Nettey, Henry; Swamidoss, Isabel; Ranieri, Nicola; Newton, Paul N

2015-06-01

The availability of falsified antimalarial drugs can be reduced with effective drug regulatory agencies and proper enforcement. Fundamental to these agencies taking action, rapid identification must be made as soon as they appear in the market place. Since falsified antimalarials occur mostly in developing countries, performing drug analysis presents itself with unique challenges. A fundamental factor in choosing a useful technique is affordability and simplicity. Therefore, we suggest a three-tiered drug evaluation strategy for identifying a falsified drug in resource-poor areas. Tier I is a simple comparison of a tablet's weight and dimensions with official specifications. Tier II uses inexpensive photometric devices (laser and fluorescence) to evaluate a tablet. Suspicious samples from Tier I and II assessments are then subjected to a colorimetric assay for active ingredients identification and quantification. In this article, we evaluate a novel colorimetric assay for the simultaneous assessment of both lumefantrine and artemether in co-formulated Coartem™ tablets, and integrate the method with two novel, low-cost, fluorescence and laser photometric devices. Image analysis software is used for the assessments. Although artemether-lumefantrine is used as an example, the strategy may be adapted to other medicines. © The American Society of Tropical Medicine and Hygiene.

Spectroscopic detection of fluorescent protein marker gene activity in genetically modified plants

Science.gov (United States)

Liew, O. W.; Chong, Jenny P. C.; Asundi, Anand K.

2005-04-01

This work focuses on developing a portable fibre optic fluorescence analyser for rapid identification of genetically modified plants tagged with a fluorescent marker gene. Independent transgenic tobacco plant lines expressing the enhanced green fluorescence protein (EGFP) gene were regenerated following Agrobacterium-mediated gene transfer. Molecular characterisation of these plant lines was carried out at the DNA level by PCR screening to confirm their transgenic status. Conventional transgene expression analysis was then carried out at the RNA level by RT-PCR and at the protein level by Western blotting using anti-GFP rabbit antiserum. The amount of plant-expressed EGFP on a Western blot was quantified against known amounts of purified EGFP by scanning densitometry. The expression level of EGFP in transformed plants was found to range from 0.1 - 0.6% of total extractable protein. A comparison between conventional western analysis of transformants and direct spectroscopic quantification using the fibre optic fluorescence analyser was made. The results showed that spectroscopic measurements of fluorescence emission from strong EGFP expressors correlated positively with Western blot data. However, the fluorescence analyser was also able to identify weakly expressing plant transformants below the detection limit of colorimetric Western blotting.

Extracellular Matrix-Mediated Maturation of Human Pluripotent Stem Cell-Derived Cardiac Monolayer Structure and Electrophysiological Function.

Science.gov (United States)

Herron, Todd J; Rocha, Andre Monteiro Da; Campbell, Katherine F; Ponce-Balbuena, Daniela; Willis, B Cicero; Guerrero-Serna, Guadalupe; Liu, Qinghua; Klos, Matt; Musa, Hassan; Zarzoso, Manuel; Bizy, Alexandra; Furness, Jamie; Anumonwo, Justus; Mironov, Sergey; Jalife, José

2016-04-01

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) monolayers generated to date display an immature embryonic-like functional and structural phenotype that limits their utility for research and cardiac regeneration. In particular, the electrophysiological function of hPSC-CM monolayers and bioengineered constructs used to date are characterized by slow electric impulse propagation velocity and immature action potential profiles. Here, we have identified an optimal extracellular matrix for significant electrophysiological and structural maturation of hPSC-CM monolayers. hPSC-CM plated in the optimal extracellular matrix combination have impulse propagation velocities ≈2× faster than previously reported (43.6±7.0 cm/s; n=9) and have mature cardiomyocyte action potential profiles, including hyperpolarized diastolic potential and rapid action potential upstroke velocity (146.5±17.7 V/s; n=5 monolayers). In addition, the optimal extracellular matrix promoted hypertrophic growth of cardiomyocytes and the expression of key mature sarcolemmal (SCN5A, Kir2.1, and connexin43) and myofilament markers (cardiac troponin I). The maturation process reported here relies on activation of integrin signaling pathways: neutralization of β1 integrin receptors via blocking antibodies and pharmacological blockade of focal adhesion kinase activation prevented structural maturation. Maturation of human stem cell-derived cardiomyocyte monolayers is achieved in a 1-week period by plating cardiomyocytes on PDMS (polydimethylsiloxane) coverslips rather than on conventional 2-dimensional cell culture formats, such as glass coverslips or plastic dishes. Activation of integrin signaling and focal adhesion kinase is essential for significant maturation of human cardiac monolayers. © 2016 American Heart Association, Inc.

Synthesis and Fluorescence Spectra of Triazolylcoumarin Fluorescent Dyes

Institute of Scientific and Technical Information of China (English)

PENG Xian-fu; LI Hong-qi

2009-01-01

Much attention is devoted to fluorescent dyes especially those with potential in versatile applications. Reactions under "click" conditions between nonfluorescent 3 - azidocoumarins and terminal alkynes produced 3 -(1, 2, 3- triazol- 1 - yl)cournarins, a novel type of fluorescent dyes with intense fluorescence. The structures of the new coumarins were characterized by 1H NMR, MS, and IR spectra. Fluorescence spectra measurement demonstrated excellent fluorescence performance of the triazolylcoumarins and this click reaction is a promising candidate for bioconjugation and bioimaging applications since both azide and alkynes are quite inert to biological systems.

Luminescent conjugated oligothiophenes for sensitive fluorescent assignment of protein inclusion bodies.

Science.gov (United States)

Klingstedt, Therése; Blechschmidt, Cristiane; Nogalska, Anna; Prokop, Stefan; Häggqvist, Bo; Danielsson, Olof; Engel, W King; Askanas, Valerie; Heppner, Frank L; Nilsson, K Peter R

2013-03-18

Small hydrophobic ligands identifying intracellular protein deposits are of great interest, as protein inclusion bodies are the pathological hallmark of several degenerative diseases. Here we report that fluorescent amyloid ligands, termed luminescent conjugated oligothiophenes (LCOs), rapidly and with high sensitivity detect protein inclusion bodies in skeletal muscle tissue from patients with sporadic inclusion body myositis (s-IBM). LCOs having a conjugated backbone of at least five thiophene units emitted strong fluorescence upon binding, and showed co-localization with proteins reported to accumulate in s-IBM protein inclusion bodies. Compared with conventional amyloid ligands, LCOs identified a larger fraction of immunopositive inclusion bodies. When the conjugated thiophene backbone was extended with terminal carboxyl groups, the LCO revealed striking spectral differences between distinct protein inclusion bodies. We conclude that 1) LCOs are sensitive, rapid and powerful tools for identifying protein inclusion bodies and 2) LCOs identify a wider range of protein inclusion bodies than conventional amyloid ligands. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Expression of pH-sensitive green fluorescent protein in Arabidopsis thaliana

Science.gov (United States)

Moseyko, N.; Feldman, L. J.

2001-01-01

This is the first report on using green fluorescent protein (GFP) as a pH reporter in plants. Proton fluxes and pH regulation play important roles in plant cellular activity and therefore, it would be extremely helpful to have a plant gene reporter system for rapid, non-invasive visualization of intracellular pH changes. In order to develop such a system, we constructed three vectors for transient and stable transformation of plant cells with a pH-sensitive derivative of green fluorescent protein. Using these vectors, transgenic Arabidopsis thaliana and tobacco plants were produced. Here the application of pH-sensitive GFP technology in plants is described and, for the first time, the visualization of pH gradients between different developmental compartments in intact whole-root tissues of A. thaliana is reported. The utility of pH-sensitive GFP in revealing rapid, environmentally induced changes in cytoplasmic pH in roots is also demonstrated.

Variability of sun-induced chlorophyll fluorescence according to stand age-related processes in a managed loblolly pine forest.

Science.gov (United States)

Colombo, Roberto; Celesti, Marco; Bianchi, Remo; Campbell, Petya K E; Cogliati, Sergio; Cook, Bruce D; Corp, Lawrence A; Damm, Alexander; Domec, Jean-Christophe; Guanter, Luis; Julitta, Tommaso; Middleton, Elizabeth M; Noormets, Asko; Panigada, Cinzia; Pinto, Francisco; Rascher, Uwe; Rossini, Micol; Schickling, Anke

2018-02-20

Leaf fluorescence can be used to track plant development and stress, and is considered the most direct measurement of photosynthetic activity available from remote sensing techniques. Red and far-red sun-induced chlorophyll fluorescence (SIF) maps were generated from high spatial resolution images collected with the HyPlant airborne spectrometer over even-aged loblolly pine plantations in North Carolina (United States). Canopy fluorescence yield (i.e., the fluorescence flux normalized by the light absorbed) in the red and far-red peaks was computed. This quantifies the fluorescence emission efficiencies that are more directly linked to canopy function compared to SIF radiances. Fluorescence fluxes and yields were investigated in relation to tree age to infer new insights on the potential of those measurements in better describing ecosystem processes. The results showed that red fluorescence yield varies with stand age. Young stands exhibited a nearly twofold higher red fluorescence yield than mature forest plantations, while the far-red fluorescence yield remained constant. We interpreted this finding in a context of photosynthetic stomatal limitation in aging loblolly pine stands. Current and future satellite missions provide global datasets of SIF at coarse spatial resolution, resulting in intrapixel mixture effects, which could be a confounding factor for fluorescence signal interpretation. To mitigate this effect, we propose a surrogate of the fluorescence yield, namely the Canopy Cover Fluorescence Index (CCFI) that accounts for the spatial variability in canopy structure by exploiting the vegetation fractional cover. It was found that spatial aggregation tended to mask the effective relationships, while the CCFI was still able to maintain this link. This study is a first attempt in interpreting the fluorescence variability in aging forest stands and it may open new perspectives in understanding long-term forest dynamics in response to future climatic

Fluorescent carbon nanoparticles derived from natural materials of mango fruit for bio-imaging probes

Science.gov (United States)

Jeong, Chan Jin; Roy, Arup Kumer; Kim, Sung Han; Lee, Jung-Eun; Jeong, Ji Hoon; Insik; Park, Sung Young

2014-11-01

Water soluble fluorescent carbon nanoparticles (FCP) obtained from a single natural source, mango fruit, were developed as unique materials for non-toxic bio-imaging with different colors and particle sizes. The prepared FCPs showed blue (FCP-B), green (FCP-G) and yellow (FCP-Y) fluorescence, derived by the controlled carbonization method. The FCPs demonstrated hydrodynamic diameters of 5-15 nm, holding great promise for clinical applications. The biocompatible FCPs demonstrated great potential in biological fields through the results of in vitro imaging and in vivo biodistribution. Using intravenously administered FCPs with different colored particles, we precisely defined the clearance and biodistribution, showing rapid and efficient urinary excretion for safe elimination from the body. These findings therefore suggest the promising possibility of using natural sources for producing fluorescent materials.Water soluble fluorescent carbon nanoparticles (FCP) obtained from a single natural source, mango fruit, were developed as unique materials for non-toxic bio-imaging with different colors and particle sizes. The prepared FCPs showed blue (FCP-B), green (FCP-G) and yellow (FCP-Y) fluorescence, derived by the controlled carbonization method. The FCPs demonstrated hydrodynamic diameters of 5-15 nm, holding great promise for clinical applications. The biocompatible FCPs demonstrated great potential in biological fields through the results of in vitro imaging and in vivo biodistribution. Using intravenously administered FCPs with different colored particles, we precisely defined the clearance and biodistribution, showing rapid and efficient urinary excretion for safe elimination from the body. These findings therefore suggest the promising possibility of using natural sources for producing fluorescent materials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04805a

Development of a real-time fluorescence loop-mediated isothermal amplification assay for rapid and quantitative detection of Fusarium oxysporum f. sp. cubense tropical race 4 in soil.

Science.gov (United States)

Zhang, Xin; Zhang, He; Pu, Jinji; Qi, Yanxiang; Yu, Qunfang; Xie, Yixian; Peng, Jun

2013-01-01

Fusarium oxysporum f. sp. cubense (Foc), the causal agent of Fusarium wilt (Panama disease), is one of the most devastating diseases of banana (Musa spp.). The Foc tropical race 4 (TR4) is currently known as a major concern in global banana production. No effective resistance is known in Musa to Foc, and no effective measures for controlling Foc once banana plants have been infected in place. Early and accurate detection of Foc TR4 is essential to protect banana industry and guide banana planting. A real-time fluorescence loop-mediated isothermal amplification assay (RealAmp) was developed for the rapid and quantitative detection of Foc TR4 in soil. The detection limit of the RealAmp assay was approximately 0.4 pg/µl plasmid DNA when mixed with extracted soil DNA or 10(3) spores/g of artificial infested soil, and no cross-reaction with other relative pathogens were observed. The RealAmp assay for quantifying genomic DNA of TR4 was confirmed by testing both artificially and naturally infested samples. Quantification of the soil-borne pathogen DNA of Foc TR4 in naturally infested samples was no significant difference compared to classic real-time PCR (P>0.05). Additionally, RealAmp assay was visual with an improved closed-tube visual detection system by adding SYBR Green I fluorescent dye to the inside of the lid prior to amplification, which avoided the inhibitory effects of the stain on DNA amplification and makes the assay more convenient in the field and could thus become a simple, rapid and effective technique that has potential as an alternative tool for the detection and monitoring of Foc TR4 in field, which would be a routine DNA-based testing service for the soil-borne pathogen in South China.

Development of a real-time fluorescence loop-mediated isothermal amplification assay for rapid and quantitative detection of Fusarium oxysporum f. sp. cubense tropical race 4 in soil.

Directory of Open Access Journals (Sweden)

Xin Zhang

Full Text Available Fusarium oxysporum f. sp. cubense (Foc, the causal agent of Fusarium wilt (Panama disease, is one of the most devastating diseases of banana (Musa spp.. The Foc tropical race 4 (TR4 is currently known as a major concern in global banana production. No effective resistance is known in Musa to Foc, and no effective measures for controlling Foc once banana plants have been infected in place. Early and accurate detection of Foc TR4 is essential to protect banana industry and guide banana planting. A real-time fluorescence loop-mediated isothermal amplification assay (RealAmp was developed for the rapid and quantitative detection of Foc TR4 in soil. The detection limit of the RealAmp assay was approximately 0.4 pg/µl plasmid DNA when mixed with extracted soil DNA or 10(3 spores/g of artificial infested soil, and no cross-reaction with other relative pathogens were observed. The RealAmp assay for quantifying genomic DNA of TR4 was confirmed by testing both artificially and naturally infested samples. Quantification of the soil-borne pathogen DNA of Foc TR4 in naturally infested samples was no significant difference compared to classic real-time PCR (P>0.05. Additionally, RealAmp assay was visual with an improved closed-tube visual detection system by adding SYBR Green I fluorescent dye to the inside of the lid prior to amplification, which avoided the inhibitory effects of the stain on DNA amplification and makes the assay more convenient in the field and could thus become a simple, rapid and effective technique that has potential as an alternative tool for the detection and monitoring of Foc TR4 in field, which would be a routine DNA-based testing service for the soil-borne pathogen in South China.

Core-shell fluorescent silica nanoparticles for sensing near-neutral pH values

International Nuclear Information System (INIS)

Gao, F.; Chen, X.; Ye, Q.; Yao, Z.; Guo, X.; Wang, L.

2011-01-01

pH-responsive fluorescent core-shell silica nanoparticles (SiNPs) were prepared by encapsulating the pH-sensitive fluorophore 8-hydroxypyrene-1,3, 6-trisulfonate into their silica shell via a facile reverse microemulsion method. The resulting SiNPs were characterized by SEM, TEM, fluorescence lifetime spectroscopy, photobleaching experiments, and photoluminescence. The core-shell structure endows the SiNPs with reduced photobleaching, excellent photostability, minimized solvatachromic shift, and increased fluorescence efficiency compared to the free fluorophore in aqueous solution. The dynamic range for sensing pH ranges from 5. 5 to 9. 0. The nanosensors show excellent stability, are highly reproducible, and enable rapid detection of pH. The results obtained with the SiNPs are in good agreement with data obtained with a glass electrode. (author)

Fluorescent quenching immune chromatographic strips with quantum dots and upconversion nanoparticles as fluorescent donors for visual detection of sulfaquinoxaline in foods of animal origin

International Nuclear Information System (INIS)

Hu, Gaoshuang; Sheng, Wei; Li, Jingmin; Zhang, Yan; Wang, Junping; Wang, Shuo

2017-01-01

In this study, two novel fluorescence quenching immune chromatographic strips (FQICS) were developed to detect sulfaquinoxaline (SQX) in foods of animal origin. These proposed FQICSs were based on fluorescence resonance energy transfer (FRET) from fluorescence donors (quantum dots or upconversion nanoparticles) to fluorescence acceptors (colloidal gold nanoparticles). Compared with traditional colloidal gold-based immune chromatographic strips (ICS), these FQICSs showed positive correlation between the fluorescent signals and the targets, and allowed user to get test results from weak fluorescent signals. The visual detection limits of these two FQICSs were both 1 ng mL −1 in standard solution and 8 μg kg −1 in samples, while the visual detection limit of the colloidal gold-based ICS was 10 ng mL −1 in standard solution and 80 μg kg −1 in samples. Besides, the results we obtained by the use of FQICS showed high agreement with those obtained by the use of commercial ELISA kits, indicating the good accuracy of these strips. As a conclusion, these proposed FQICS based on quantum dots and upconversion nanoparticles can be applied in sensitive, rapid and on-site detection of SQX in foods of animal origin. - Highlights: • Two novel FQICS based on FRET were developed for the first time. • QDs and UCNPs were used as fluorescent donors in the FQICS. • The proposed FQICS showed low LOD compared with traditional ICS. • The proposed FQICS were applied in real samples analysis. • The proposed FQICS were verified by commercial ELISA kits.

The application of X-ray fluorescence spectrometry to prospecting potential gold deposits

International Nuclear Information System (INIS)

Shang Fengjun; Wang Haixia; Zhou Rongsheng

2001-01-01

The fieldwork high-sensitivity X-ray fluorescence analysis (FXFA) adopting miniaturized X-ray tube, Si-PIN detector with peltier cooler and notebook PC spectrometry is presented. Using this system, the authors carried out a preliminary research of its application to some gold mine in Sichuan. According to the close relationship between the high-grade element arsenic and gold in ore-forming components, X-ray fluorescence spectrometry can be used to reveal the existence of potential gold mineralization in fields rapidly. This is of great significance in guiding the field geological collection

Differential Postnatal Expression of Neuronal Maturation Markers in the Dentate Gyrus of Mice and Rats

Directory of Open Access Journals (Sweden)

Tijana Radic

2017-11-01

Full Text Available The dentate gyrus (DG is a unique structure of the hippocampus that is distinguished by ongoing neurogenesis throughout the lifetime of an organism. The development of the DG, which begins during late gestation and continues during the postnatal period, comprises the structural formation of the DG as well as the establishment of the adult neurogenic niche in the subgranular zone (SGZ. We investigated the time course of postnatal maturation of the DG in male C57BL/6J mice and male Sprague-Dawley rats based on the distribution patterns of the immature neuronal marker doublecortin (DCX and a marker for mature neurons, calbindin (CB. Our findings demonstrate that the postnatal DG is marked by a substantial maturation with a high number of DCX-positive granule cells (GCs during the first two postnatal weeks followed by a progression toward more mature patterns and increasing numbers of CB-positive GCs within the subsequent 2 weeks. The most substantial shift in maturation of the GC population took place between P7 and P14 in both mice and rats, when young, immature DCX-positive GCs became confined to the innermost part of the GC layer (GCL, indicative of the formation of the SGZ. These results suggest that the first month of postnatal development represents an important transition phase during which DG neurogenesis and the maturation course of the GC population becomes analogous to the process of adult neurogenesis. Therefore, the postnatal DG could serve as an attractive model for studying a growing and functionally maturing neural network. Direct comparisons between mice and rats revealed that the transition from immature DCX-positive to mature CB-positive GCs occurs more rapidly in the rat by approximately 4–6 days. The remarkable species difference in the speed of maturation on the GC population level may have important implications for developmental and neurogenesis research in different rodent species and strains.

In vivo target bio-imaging of Alzheimer's disease by fluorescent zinc oxide nanoclusters.

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Lai, Lanmei; Zhao, Chunqiu; Su, Meina; Li, Xiaoqi; Liu, Xiaoli; Jiang, Hui; Amatore, Christian; Wang, Xuemei

2016-07-21

Alzheimer's disease (AD) is an irreversible neurodegenerative disease which is difficult to cure. When Alzheimer's disease occurs, the level of zinc ions in the brain changes, and the relevant amount of zinc ions continue decreasing in the cerebrospinal fluid and plasma of Alzheimer's patients with disease exacerbation. In view of these considerations, we have explored a new strategy for the in vivo rapid fluorescence imaging of Alzheimer's disease through target bio-labeling of zinc oxide nanoclusters which were biosynthesized in vivo in the Alzheimer's brain via intravenous injection of zinc gluconate solution. By using three-month-old and six-month-old Alzheimer's model mice as models, our observations demonstrate that biocompatible zinc ions could pass through the blood-brain barrier of the Alzheimer's disease mice and generate fluorescent zinc oxide nanoclusters (ZnO NCs) through biosynthesis, and then the bio-synthesized ZnO NCs could readily accumulate in situ on the hippocampus specific region for the in vivo fluorescent labeling of the affected sites. This study provides a new way for the rapid diagnosis of Alzheimer's disease and may have promising prospects in the effective diagnosis of Alzheimer's disease.

Lettuce flavonoids screening and phenotyping by chlorophyll fluorescence excitation ratio.

Science.gov (United States)

Zivcak, Marek; Brückova, Klaudia; Sytar, Oksana; Brestic, Marian; Olsovska, Katarina; Allakhverdiev, Suleyman I

2017-06-01

Environmentally induced variation and the genotypic differences in flavonoid and phenolic content in lettuce can be reliably detected using the appropriate parameters derived from the records of rapid non-invasive fluorescence technique. The chlorophyll fluorescence excitation ratio method was designed as a rapid and non-invasive tool to estimate the content of UV-absorbing phenolic compounds in plants. Using this technique, we have assessed the dynamics of accumulation of flavonoids related to developmental changes and environmental effects. Moreover, we have tested appropriateness of the method to identify the genotypic differences and fluctuations in total phenolics and flavonoid content in lettuce. Six green and two red genotypes of lettuce (Lactuca sativa L.) grown in pots were exposed to two different environments for 50 days: direct sunlight (UV-exposed) and greenhouse conditions (low UV). The indices based on the measurements of chlorophyll fluorescence after red, green and UV excitation indicated increase of the content of UV-absorbing compounds and anthocyanins in the epidermis of lettuce leaves. In similar, the biochemical analyses performed at the end of the experiment confirmed significantly higher total phenolic and flavonoid content in lettuce plants exposed to direct sun compared to greenhouse conditions and in red compared to green genotypes. As the correlation between the standard fluorescence indices and the biochemical records was negatively influenced by the presence of red genotypes, we proposed the use of a new parameter named Modified Flavonoid Index (MFI) taking into an account both absorbance changes due to flavonol and anthocyanin content, for which the correlation with flavonoid and phenolic content was relatively good. Thus, our results confirmed that the fluorescence excitation ratio method is useful for identifying the major differences in phenolic and flavonoid content in lettuce plants and it can be used for high-throughput pre

Click strategies for single-molecule protein fluorescence.

Science.gov (United States)

Milles, Sigrid; Tyagi, Swati; Banterle, Niccolò; Koehler, Christine; VanDelinder, Virginia; Plass, Tilman; Neal, Adrian P; Lemke, Edward A

2012-03-21

Single-molecule methods have matured into central tools for studies in biology. Foerster resonance energy transfer (FRET) techniques, in particular, have been widely applied to study biomolecular structure and dynamics. The major bottleneck for a facile and general application of these studies arises from the need to label biological samples site-specifically with suitable fluorescent dyes. In this work, we present an optimized strategy combining click chemistry and the genetic encoding of unnatural amino acids (UAAs) to overcome this limitation for proteins. We performed a systematic study with a variety of clickable UAAs and explored their potential for high-resolution single-molecule FRET (smFRET). We determined all parameters that are essential for successful single-molecule studies, such as accessibility of the probes, expression yield of proteins, and quantitative labeling. Our multiparameter fluorescence analysis allowed us to gain new insights into the effects and photophysical properties of fluorescent dyes linked to various UAAs for smFRET measurements. This led us to determine that, from the extended tool set that we now present, genetically encoding propargyllysine has major advantages for state-of-the-art measurements compared to other UAAs. Using this optimized system, we present a biocompatible one-step dual-labeling strategy of the regulatory protein RanBP3 with full labeling position freedom. Our technique allowed us then to determine that the region encompassing two FxFG repeat sequences adopts a disordered but collapsed state. RanBP3 serves here as a prototypical protein that, due to its multiple cysteines, size, and partially disordered structure, is not readily accessible to any of the typical structure determination techniques such as smFRET, NMR, and X-ray crystallography.

Tracking transparent monogenean parasites on fish from infection to maturity

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Alejandro Trujillo-González

2015-12-01

Full Text Available The infection dynamics and distribution of the ectoparasitic fish monogenean Neobenedenia sp. (Monogenea: Capsalidae throughout its development was examined on barramundi, Lates calcarifer (Bloch (Latidae, by labelling transparent, ciliated larvae (oncomiracidia with a fluorescent dye. Replicate fish were each exposed to approximately 50 fluorescent oncomiracidia and then examined for parasites using an epifluorescence stereomicroscope at 10 time intervals post-exposure (15, 30, 60, 120 min, 24, 48 h, four, eight, 12, and 16 days. Fluorescent labelling revealed that parasites attached underneath and on the surface of the scales of host fish. Parasite infection success was 20% within 15 min, and peaked at 93% two days post-exposure, before gradually declining between four and sixteen days. Differences in parasite distribution on L. calcarifer over time provided strong evidence that Neobenedenia sp. larvae settled opportunistically and then migrated to specific microhabitats. Parasites initially attached (<24 h in greater mean numbers on the body surface (13 ± 1.5 compared to the fins (4 ± 0.42 and head region (2 ± 0.41. Once larvae recruitment had ceased (48 h, there were significantly higher mean post-larvae counts on the head (5 ± 3.4 and fins (12 ± 3 compared to previous time intervals. Neobenedenia sp. aggregated on the eyes, fins, and dorsal and ventral extremities on the main body. As parasites neared sexual maturity, there was a marked aggregation on the fins (22 ± 2.35 compared to the head (4 ± 0.97 and body (9 ± 1.33, indicating that Neobenedenia sp. may form mating aggregations.

Maturity Models

DEFF Research Database (Denmark)

Lasrado, Lester Allan; Vatrapu, Ravi

2016-01-01

Recent advancements in set theory and readily available software have enabled social science researchers to bridge the variable-centered quantitative and case-based qualitative methodological paradigms in order to analyze multi-dimensional associations beyond the linearity assumptions, aggregate...... effects, unicausal reduction, and case specificity. Based on the developments in set theoretical thinking in social sciences and employing methods like Qualitative Comparative Analysis (QCA), Necessary Condition Analysis (NCA), and set visualization techniques, in this position paper, we propose...... and demonstrate a new approach to maturity models in the domain of Information Systems. This position paper describes the set-theoretical approach to maturity models, presents current results and outlines future research work....

A new turn-on fluorimetric method for the rapid speciation of Cr(III)/Cr(VI) species in tea samples with rhodamine-based fluorescent reagent

Science.gov (United States)

Özyol, Esra; Saçmacı, Şerife; Saçmacı, Mustafa; Ülgen, Ahmet

2018-02-01

A new fluorimetric method with rhodamine-based fluorescent agent was developed for the rapid speciation of Cr(III)/Cr(VI) in tea, soil and water samples. The system, which utilizes a fluorescent reagent, was used for the first time after synthesis/characterization of 3‧,6‧-bis(diethylamino)-2-{[(1E)-(2,4-dimethoxyphenyl)methylene] amino}spiro[isoindole-1,9‧-xanthen]-3(2H)-one (BDAS). The reagent responds instantaneously at room temperature in a 1:1 stoichiometric manner to the amount of Cr(III). The selectivity of this system for Cr(III) over other metal ions is remarkably high, and its sensitivity is below 0.01 mg L- 1 in aqueous solutions which enables a simplification without any pretreatment of the real sample. The method has a wide linear range of 0.1-10 mg L- 1 and a detection limit of 0.15 μg L- 1 for Cr(III) while the relative standard deviation was 0.1% for 0.1 mg L- 1 Cr(III) concentration. The results of detection and recovery experiments for Cr(III) in tea, soil and water were satisfactory, indicating that the method has better feasibility and application potential in the routine determination and speciation of Cr(III)/Cr(VI). The results of analysis of the certified reference material (INCT-TL-1 tea sample and CWW-TM-D waste water) are in good agreement with the certified value.

Detection of trace tetracycline in fish via synchronous fluorescence quenching with carbon quantum dots coated with molecularly imprinted silica

Science.gov (United States)

Yang, Ji; Lin, Zheng-Zhong; Nur, A.-Zha; Lu, Yan; Wu, Ming-Hui; Zeng, Jun; Chen, Xiao-Mei; Huang, Zhi-Yong

2018-02-01

A novel fluorescence-based sensor combining synchronous fluorescence spectroscopy (SFS) with molecularly imprinted polymers (MIPs) was fabricated with reverse microemulsion method. Tetracycline (TC), (3-aminopropyl) triethoxysilane (APTES), tetraethyl orthosilicate (TEOS) and carbon quantum dots (CDs) were used as template, functional monomer, cross-linker and signal sources respectively in the probe preparation. A synchronous fluorescence emission (λem) at 355 nm was observed for the prepared MIP-coated CDs (MIP@CDs) particles when the wavelength interval (Δλ) was set as 70 nm, and the synchronous fluorescence intensity could be rapidly and efficiently quenched by TC based on inner filter effect (IFE). The quenching efficiencies of synchronous fluorescence intensity was linearly fitted with tetracycline (TC) concentrations ranging from 0.1 to 50 μmol L- 1 with a detection limit (DL) of 9 nmol L- 1 (3σ, n = 9). The MIP@CDs was used as a probe to detect TC in fish samples with the recoveries ranging from 98.4% to 103.1% and the relative standard deviation less than 6.0%. The results illustrated that the as-prepared MIP@CDs could be applied to the detection of trace TC in fish samples with rapidity, high sensitivity and accuracy.

Aptamer-Based Dual-Functional Probe for Rapid and Specific Counting and Imaging of MCF-7 Cells.

Science.gov (United States)

Yang, Bin; Chen, Beibei; He, Man; Yin, Xiao; Xu, Chi; Hu, Bin

2018-02-06

Development of multimodal detection technologies for accurate diagnosis of cancer at early stages is in great demand. In this work, we report a novel approach using an aptamer-based dual-functional probe for rapid, sensitive, and specific counting and visualization of MCF-7 cells by inductively coupled plasma-mass spectrometry (ICP-MS) and fluorescence imaging. The probe consists of a recognition unit of aptamer to catch cancer cells specifically, a fluorescent dye (FAM) moiety for fluorescence resonance energy transfer (FRET)-based "off-on" fluorescence imaging as well as gold nanoparticles (Au NPs) tag for both ICP-MS quantification and fluorescence quenching. Due to the signal amplification effect and low spectral interference of Au NPs in ICP-MS, an excellent linearity and sensitivity were achieved. Accordingly, a limit of detection of 81 MCF-7 cells and a relative standard deviation of 5.6% (800 cells, n = 7) were obtained. The dynamic linear range was 2 × 10 2 to 1.2 × 10 4 cells, and the recoveries in human whole blood were in the range of 98-110%. Overall, the established method provides quantitative and visualized information on MCF-7 cells with a simple and rapid process and paves the way for a promising strategy for biomedical research and clinical diagnostics.

Functional incorporation of green fluorescent protein into hepatitis B virus envelope particles

International Nuclear Information System (INIS)

Lambert, Carsten; Thome, Nicole; Kluck, Christoph J.; Prange, Reinhild

2004-01-01

The envelope of hepatitis B virus (HBV), containing the L, M, and S proteins, is essential for virus entry and maturation. For direct visualization of HBV, we determined whether envelope assembly could accommodate the green fluorescent protein (GFP). While the C-terminal addition of GFP to S trans-dominant negatively inhibited empty envelope particle secretion, the N-terminal GFP fusion to S (GFP.S) was co-integrated into the envelope, giving rise to fluorescent particles. Microscopy and topogenesis analyses demonstrated that the proper intracellular distribution and folding of GFP.S, required for particle export were rescued by interprotein interactions with wild-type S. Thereby, a dual location of GFP, inside and outside the envelope, was observed. GFP.S was also efficiently packaged into the viral envelope, and these GFP-tagged virions retained the capacity for attachment to HBV receptor-positive cells in vitro. Together, GFP-tagged virions should be suitable to monitor HBV uptake and egress in live hepatocytes

Fluorescence Image Segmentation by using Digitally Reconstructed Fluorescence Images

OpenAIRE

Blumer, Clemens; Vivien, Cyprien; Oertner, Thomas G; Vetter, Thomas

2011-01-01

In biological experiments fluorescence imaging is used to image living and stimulated neurons. But the analysis of fluorescence images is a difficult task. It is not possible to conclude the shape of an object from fluorescence images alone. Therefore, it is not feasible to get good manual segmented nor ground truth data from fluorescence images. Supervised learning approaches are not possible without training data. To overcome this issues we propose to synthesize fluorescence images and call...

Naturally Engineered Maturation of Cardiomyocytes

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Gaetano J. Scuderi

2017-05-01

Full Text Available Ischemic heart disease remains one of the most prominent causes of mortalities worldwide with heart transplantation being the gold-standard treatment option. However, due to the major limitations associated with heart transplants, such as an inadequate supply and heart rejection, there remains a significant clinical need for a viable cardiac regenerative therapy to restore native myocardial function. Over the course of the previous several decades, researchers have made prominent advances in the field of cardiac regeneration with the creation of in vitro human pluripotent stem cell-derived cardiomyocyte tissue engineered constructs. However, these engineered constructs exhibit a functionally immature, disorganized, fetal-like phenotype that is not equivalent physiologically to native adult cardiac tissue. Due to this major limitation, many recent studies have investigated approaches to improve pluripotent stem cell-derived cardiomyocyte maturation to close this large functionality gap between engineered and native cardiac tissue. This review integrates the natural developmental mechanisms of cardiomyocyte structural and functional maturation. The variety of ways researchers have attempted to improve cardiomyocyte maturation in vitro by mimicking natural development, known as natural engineering, is readily discussed. The main focus of this review involves the synergistic role of electrical and mechanical stimulation, extracellular matrix interactions, and non-cardiomyocyte interactions in facilitating cardiomyocyte maturation. Overall, even with these current natural engineering approaches, pluripotent stem cell-derived cardiomyocytes within three-dimensional engineered heart tissue still remain mostly within the early to late fetal stages of cardiomyocyte maturity. Therefore, although the end goal is to achieve adult phenotypic maturity, more emphasis must be placed on elucidating how the in vivo fetal microenvironment drives cardiomyocyte

Characterizing the structural maturity of fault zones using high-resolution earthquake locations.

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Perrin, C.; Waldhauser, F.; Scholz, C. H.

2017-12-01

We use high-resolution earthquake locations to characterize the three-dimensional structure of active faults in California and how it evolves with fault structural maturity. We investigate the distribution of aftershocks of several recent large earthquakes that occurred on immature faults (i.e., slow moving and small cumulative displacement), such as the 1992 (Mw7.3) Landers and 1999 (Mw7.1) Hector Mine events, and earthquakes that occurred on mature faults, such as the 1984 (Mw6.2) Morgan Hill and 2004 (Mw6.0) Parkfield events. Unlike previous studies which typically estimated the width of fault zones from the distribution of earthquakes perpendicular to the surface fault trace, we resolve fault zone widths with respect to the 3D fault surface estimated from principal component analysis of local seismicity. We find that the zone of brittle deformation around the fault core is narrower along mature faults compared to immature faults. We observe a rapid fall off of the number of events at a distance range of 70 - 100 m from the main fault surface of mature faults (140-200 m fault zone width), and 200-300 m from the fault surface of immature faults (400-600 m fault zone width). These observations are in good agreement with fault zone widths estimated from guided waves trapped in low velocity damage zones. The total width of the active zone of deformation surrounding the main fault plane reach 1.2 km and 2-4 km for mature and immature faults, respectively. The wider zone of deformation presumably reflects the increased heterogeneity in the stress field along complex and discontinuous faults strands that make up immature faults. In contrast, narrower deformation zones tend to align with well-defined fault planes of mature faults where most of the deformation is concentrated. Our results are in line with previous studies suggesting that surface fault traces become smoother, and thus fault zones simpler, as cumulative fault slip increases.

Spatial variability of oceanic phycoerythrin spectral types derived from airborne laser-induced fluorescence emissions

Science.gov (United States)

Hoge, Frank E.; Wright, C. Wayne; Kana, Todd M.; Swift, Robert N.; Yungel, James K.

1998-07-01

We report spatial variability of oceanic phycoerythrin spectral types detected by means of a blue spectral shift in airborne laser-induced fluorescence emission. The blue shift of the phycoerythrobilin fluorescence is known from laboratory studies to be induced by phycourobilin chromophore substitution at phycoerythrobilin chromophore sites in some strains of phycoerythrin-containing marine cyanobacteria. The airborne 532-nm laser-induced phycoerythrin fluorescence of the upper oceanic volume showed distinct segregation of cyanobacterial chromophore types in a flight transect from coastal water to the Sargasso Sea in the western North Atlantic. High phycourobilin levels were restricted to the oceanic (oligotrophic) end of the flight transect, in agreement with historical ship findings. These remotely observed phycoerythrin spectral fluorescence shifts have the potential to permit rapid, wide-area studies of the spatial variability of spectrally distinct cyanobacteria, especially across interfacial regions of coastal and oceanic water masses. Airborne laser-induced phytoplankton spectral fluorescence observations also further the development of satellite algorithms for passive detection of phytoplankton pigments. Optical modifications to the NASA Airborne Oceanographic Lidar are briefly described that permitted observation of the fluorescence spectral shifts.

Rapid on-site monitoring of Legionella pneumophila in cooling tower water using a portable microfluidic system.

Science.gov (United States)

Yamaguchi, Nobuyasu; Tokunaga, Yusuke; Goto, Satoko; Fujii, Yudai; Banno, Fumiya; Edagawa, Akiko

2017-06-08

Legionnaires' disease, predominantly caused by the bacterium Legionella pneumophila, has increased in prevalence worldwide. The most common mode of transmission of Legionella is inhalation of contaminated aerosols, such as those generated by cooling towers. Simple, rapid and accurate methods to enumerate L. pneumophila are required to prevent the spread of this organism. Here, we applied a microfluidic device for on-chip fluorescent staining and semi-automated counting of L. pneumophila in cooling tower water. We also constructed a portable system for rapid on-site monitoring and used it to enumerate target bacterial cells rapidly flowing in the microchannel. A fluorescently-labelled polyclonal antibody was used for the selective detection of L. pneumophila serogroup 1 in the samples. The counts of L. pneumophila in cooling tower water obtained using the system and fluorescence microscopy were similar. The detection limit of the system was 10 4  cells/ml, but lower numbers of L. pneumophila cells (10 1 to 10 3  cells/ml) could be detected following concentration of 0.5-3 L of the water sample by filtration. Our technique is rapid to perform (1.5 h), semi-automated (on-chip staining and counting), and portable for on-site measurement, and it may therefore be effective in the initial screening of Legionella contamination in freshwater.

From maturity to value-added innovation: lessons from the pharmaceutical and agro-biotechnology industries.

Science.gov (United States)

Mittra, James; Tait, Joyce; Wield, David

2011-03-01

The pharmaceutical and agro-biotechnology industries have been confronted by dwindling product pipelines and rapid developments in life sciences, thus demanding a strategic rethink of conventional research and development. Despite offering both industries a solution to the pipeline problem, the life sciences have also brought complex regulatory challenges for firms. In this paper, we comment on the response of these industries to the life science trajectory, in the context of maturing conventional small-molecule product pipelines and routes to market. The challenges of managing transition from maturity to new high-value-added innovation models are addressed. Furthermore, we argue that regulation plays a crucial role in shaping the innovation systems of both industries, and as such, we suggest potentially useful changes to the current regulatory system. Copyright © 2010 Elsevier Ltd. All rights reserved.

Chemical analysis by X-ray fluorescence, of niobium in high-strength plate steels

International Nuclear Information System (INIS)

Iozzi, F.B.; Dias, M.J.P.

1981-01-01

The use of X-ray fluorescence spectrometry in quantitative analysis of niobium in steels, as an alternative solution for optical emission spectrometry, in the rapid chemical control of steel fabrication by LD type converters, is presented. (M.C.K.) [pt

RESEARCH ON REDUCING THE LENGTH OF MATURATION IN USING ELECTROSTIMULATION OF BEEF

Directory of Open Access Journals (Sweden)

FELICIA DIMA

2014-01-01

Full Text Available From technological point of view in the food industry has been obtained meat maturation using different methods: storage under controlled conditions, the use of enzymes or mechanical equipment tenderization musculature. Was also reported that electrical stimulation of carcasses immediately after slaughter procedure can increase the degree of maturation of the meat. Meat and meat products are subjected to reduce during chilling and freezing temperatures principal for reasons of conservation or meat packing. Particular attention must be paid to temperature control, especially before rigor mortis, knowing that too rapid cooling could lead to a cold shortening or thaw rigor during the thaw. During application of the electrostimulation process, occur physical and biochemical changes, meaning that this one has some effect on the technological properties of meat. It has obtained a reduction of maturation of beef with the electrostimulation of half-carcasses of cattle, verified by the increase of non-protein nitrogen in meat. The same time it has been considerably improved the texture and firmness of the muscles, which allows the use of beef in fast food products (ready to cook. Researches have revealed the conclusion that the use of the portable device for electrostimulation, in the described conditions, has induced positive transformations improving meat quality of adult beef.

Cortical bone growth and maturational changes in dwarf rats induced by recombinant human growth hormone

Science.gov (United States)

Martinez, D. A.; Orth, M. W.; Carr, K. E.; Vanderby, R. Jr; Vailas, A. C.

1996-01-01

The growth hormone (GH)-deficient dwarf rat was used to investigate recombinant human (rh) GH-induced bone formation and to determine whether rhGH facilitates simultaneous increases in bone formation and bone maturation during rapid growth. Twenty dwarf rats, 37 days of age, were randomly assigned to dwarf plus rhGH (GH; n = 10) and dwarf plus vehicle (n = 10) groups. The GH group received 1.25 mg rhGH/kg body wt two times daily for 14 days. Biochemical, morphological, and X-ray diffraction measurements were performed on the femur middiaphysis. rhGH stimulated new bone growth in the GH group, as demonstrated by significant increases (P < 0.05) in longitudinal bone length (6%), middiaphyseal cross-sectional area (20%), and the amount of newly accreted bone collagen (28%) in the total pool of middiaphyseal bone collagen. Cortical bone density, mean hydroxyapatite crystal size, and the calcium and collagen contents (microgram/mm3) were significantly smaller in the GH group (P < 0.05). Our findings suggest that the processes regulating new collagen accretion, bone collagen maturation, and mean hydroxyapatite crystal size may be independently regulated during rapid growth.

What kind of oil company do we need? Maturity and industrial structure on the Norwegian Shelf

International Nuclear Information System (INIS)

Noreng, Oeystein

1998-01-01

After many years with relatively high oil prices and moderately good oil discoveries, there is today an investment pressure on the Shelf. Many current development projects concern smaller discoveries made a long time ago. Thus the present rapid development depletes a capital of discoveries made at an early phase when the Norwegian Shelf was less mature. On this background, this presentation suggests that perhaps Norway, as a mature oil province, may not need the same kind of oil companies that dominated the petroleum activities during the development to maturity. It is experienced internationally that the various phases in the development of an oil province require different competence and thus different companies. Less oil has been found the last years than what has been produced. The command is now to find more oil. The question is how and by what company. Advantages and disadvantages are discussed for four categories of companies: (1) state companies, (2) large multinational, (3) independent, and (4) small newcomers. A section on maturing and the interest of the state as the property owner discusses the processes from large-scale operation to diversity, and maturing and the need for selective competence and low costs. Finally the paper discusses the negotiation policy of the state, political instruments and the company structure and reviews some experience from U.S.A. and UK. 1 table

Label free selective detection of estriol using graphene oxide-based fluorescence sensor

Science.gov (United States)

Kushwaha, H. S.; Sao, Reshma; Vaish, Rahul

2014-07-01

Water-soluble and fluorescent Graphene oxide (GO) is biocompatible, easy, and economical to synthesize. Interestingly, GO is also capable of quenching fluorescence. On the basis of its fluorescence and quenching abilities, GO has been reported to serve as an energy acceptor in a fluorescence resonance energy transfer (FRET) sensor. GO-based FRET biosensors have been widely reported for sensing of proteins, nucleic acid, ATP (Adenosine triphosphate), etc. GO complexes with fluorescent dyes and enzymes have been used to sense metal ions. Graphene derivatives have been used for sensing endocrine-disrupting chemicals like bisphenols and chlorophenols with high sensitivity and good reproducibility. On this basis, a novel GO based fluorescent sensor has been successfully designed to detect estriol with remarkable selectivity and sensitivity. Estriol is one of the three estrogens in women and is considered to be medically important. Estriol content of maternal urine or plasma acts as an important screening marker for estimating foetal growth and development. In addition, estriol is also used as diagnostic marker for diseases like breast cancer, osteoporosis, neurodegenerative and cardiovascular diseases, insulin resistance, lupus erythematosus, endometriosis, etc. In this present study, we report for the first time a rapid, sensitive with detection limit of 1.3 nM, selective and highly biocompatible method for label free detection of estriol under physiological conditions using fluorescence assay.

Strategies of molecular imprinting-based fluorescence sensors for chemical and biological analysis.

Science.gov (United States)

Yang, Qian; Li, Jinhua; Wang, Xiaoyan; Peng, Hailong; Xiong, Hua; Chen, Lingxin

2018-07-30

One pressing concern today is to construct sensors that can withstand various disturbances for highly selective and sensitive detecting trace analytes in complicated samples. Molecularly imprinted polymers (MIPs) with tailor-made binding sites are preferred to be recognition elements in sensors for effective targets detection, and fluorescence measurement assists in highly sensitive detection and user-friendly control. Accordingly, molecular imprinting-based fluorescence sensors (MI-FL sensors) have attracted great research interest in many fields such as chemical and biological analysis. Herein, we comprehensively review the recent advances in MI-FL sensors construction and applications, giving insights on sensing principles and signal transduction mechanisms, focusing on general construction strategies for intrinsically fluorescent or nonfluorescent analytes and improvement strategies in sensing performance, particularly in sensitivity. Construction strategies are well overviewed, mainly including the traditional indirect methods of competitive binding against pre-bound fluorescent indicators, employment of fluorescent functional monomers and embedding of fluorescence substances, and novel rational designs of hierarchical architecture (core-shell/hollow and mesoporous structures), post-imprinting modification, and ratiometric fluorescence detection. Furthermore, MI-FL sensor based microdevices are discussed, involving micromotors, test strips and microfluidics, which are more portable for rapid point-of-care detection and in-field diagnosing. Finally, the current challenges and future perspectives of MI-FL sensors are proposed. Copyright © 2018 Elsevier B.V. All rights reserved.

Potential mercury emissions from fluorescent lamps production and obsolescence in mainland China.

Science.gov (United States)

Tan, Quanyin; Li, Jinhui

2016-01-01

The use of fluorescent lamps has expanded rapidly all over the world in recent years, because of their energy-saving capability. Consequently, however, mercury emissions from production, breakage, and discard of the lamps are drawing increasing concern from the public. This article focuses on evaluating the amount of mercury used for fluorescent lamp production, as well as the potential mercury emissions during production and breakage, in mainland China. It is expected to provide a comprehensive understanding about the risks present in the mercury from fluorescent lamps, and to know about the impacts of the policies on fluorescent lamps after their implementation. It is estimated that, in 2020, mercury consumption will be about 11.30-15.69 tonnes, a significant reduction of 34.9%-37.4% from that used in 2013, owing to improvement in mercury dosing dosage technology and tighter limitations on mercury content in fluorescent lamps. With these improvements, the amount of mercury remaining in fluorescent lamps and released during production is estimated to be 10.71-14.86 and 0.59-0.83 tonnes, respectively; the mercury released from waste fluorescent lamps is estimated to be about 5.37-7.59 tonnes. Also, a significant reduction to the mercury emission can be expected when a collection and treatment system is well established and conducted in the future. © The Author(s) 2015.

Highly selective detection of glutathione using a NIP/Cu2+ complex fluorescent probe

International Nuclear Information System (INIS)

Liang Wenrui; Zhao Zhi; Zhang Yang; Wang Qiusheng; Zhao Xin; Ouyang Jie

2012-01-01

A novel fluorescent compound, 4-(trimethyl ammonium chloride)acetamide-2-(1H-naphtho[2,3-d]imidazol-2-yl)phenol (TMACA-NIP), was synthesized and used as a fluorescent probe for detecting glutathione reduced (GSH). The new NIP-based probe exhibited high fluorescence in water, which was quenched during the presence of copper (II) due to the complexation between TMACA-NIP and Cu 2+ . But after adding GSH into the TMACA-NIP and Cu 2+ system, the fluorescence of TMACA-NIP was recovered because the binding force between GSH and Cu 2+ is stronger than that between TMACA-NIP and Cu 2+ , which destroys the equilibrium between NIP and copper (II) ions and releases the fluorescence probe of TMACA-NIP. This three-component competing system of NIP/Cu 2+ /GSH can be used to detect GSH simply and rapidly. - Highlights: ► A novel fluorescence probe was developed to detect GSH that operates in aqueous solution. ► TMACA-NIP was synthesized and employed as “read-out” units of NIP/Cu 2+ /GSH. ► NIP-based probe shows high selectivity over other sulfhydryl compounds.

Rapid flow cytometry analysis of antimicrobial properties of nettle powder and cranberry powder

Science.gov (United States)

Hattuniemi, Maarit; Korhonen, Johanna; Jaakkola, Mari; Räty, Jarkko; Virtanen, Vesa

2010-11-01

Both nettle (Urtica dioica) and cranberry (Vaccinium oxycoccus) are widely known to have good influence on health. The aim of this study was to investigate antimicrobial properties of nettle powder and cranberry powder against Escherichia coli (E. coli) and monitor the growth of the bacteria by a rapid flow cytometry (FCM) method. For FCM measurements samples were stained with fluorescent dyes. The inhibitory effects of plant material on growth of E. coli were estimated by comparing the results of control sample (E. coli) to E. coli samples with plant material. FCM offers both a brilliant tool to investigate the kinetics of the growth of bacterium, since subsamples can be taken from the same liquid medium during the growing period and with fluorescent dyes a rapid method to investigate viability of the bacterium.

Time-resolved UV-excited microarray reader for fluorescence energy transfer (FRET) measurements

Science.gov (United States)

Orellana, Adelina; Hokkanen, Ari P.; Pastinen, Tomi; Takkinen, Kristina; Soderlund, Hans

2001-05-01

Analytical systems based on immunochemistry are largely used in medical diagnostics and in biotechnology. There is a significant pressure to develop the present assay formats to become easier to use, faster, and less reagent consuming. Further developments towards high density array--like multianalyte measurement systems would be valuable. To this aim we have studied the applicability of fluorescence resonance energy transfer and time-resolved fluorescence resonance energy transfer in immunoassays on microspots and in microwells. We have used engineered recombinant antibodies detecting the pentameric protein CRP as a model analyte system, and tested different assay formats. We describe also the construction of a time-resolved scanning epifluorometer with which we could measure the FRET interaction between the slow fluorescence decay from europium chelates and its energy transfer to the rapidly decaying fluorophore Cy5.

7 CFR 51.1904 - Maturity classification.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Maturity classification. 51.1904 Section 51.1904... STANDARDS) United States Consumer Standards for Fresh Tomatoes Size and Maturity Classification § 51.1904 Maturity classification. Tomatoes which are characteristically red when ripe, but are not overripe or soft...

A fiber-optic sorbitol biosensor based on NADH fluorescence detection toward rapid diagnosis of diabetic complications.

Science.gov (United States)

Gessei, Tomoko; Arakawa, Takahiro; Kudo, Hiroyuki; Mitsubayashi, Kohji

2015-09-21

Accumulation of sorbitol in the tissue is known to cause microvascular diabetic complications. In this paper, a fiber-optic biosensor for sorbitol which is used as a biomarker of diabetic complications was developed and tested. The biosensor used a sorbitol dehydrogenase from microorganisms of the genus Flavimonas with high substrate specificity and detected the fluorescence of reduced nicotinamide adenine dinucleotide (NADH) by the enzymatic reaction. An ultraviolet light emitting diode (UV-LED) was used as the excitation light source of NADH. The fluorescence of NADH was detected using a spectrometer or a photomultiplier tube (PMT). The UV-LED and the photodetector were coupled using a Y-shaped optical fiber. In the experiment, an optical fiber probe with a sorbitol dehydrogenase immobilized membrane was placed in a cuvette filled with a phosphate buffer containing the oxidized form of nicotinamide adenine dinucleotide (NAD(+)). The changes in NADH fluorescence intensity were measured after adding a standard sorbitol solution. According to the experimental assessment, the calibration range of the sorbitol biosensor systems using a spectrometer and a PMT was 5.0-1000 μmol L(-1) and 1.0-1000 μmol L(-1), respectively. The sorbitol biosensor system using the sorbitol dehydrogenase from microorganisms of the genus Flavimonas has high selectivity and sensitivity compared with that from sheep liver. The sorbitol biosensor allows for point-of-care testing applications or daily health care tests for diabetes patients.

Cervical vertebral maturation as a biologic indicator of skeletal maturity.

Science.gov (United States)

Santiago, Rodrigo César; de Miranda Costa, Luiz Felipe; Vitral, Robert Willer Farinazzo; Fraga, Marcelo Reis; Bolognese, Ana Maria; Maia, Lucianne Cople

2012-11-01

To identify and review the literature regarding the reliability of cervical vertebrae maturation (CVM) staging to predict the pubertal spurt. The selection criteria included cross-sectional and longitudinal descriptive studies in humans that evaluated qualitatively or quantitatively the accuracy and reproducibility of the CVM method on lateral cephalometric radiographs, as well as the correlation with a standard method established by hand-wrist radiographs. The searches retrieved 343 unique citations. Twenty-three studies met the inclusion criteria. Six articles had moderate to high scores, while 17 of 23 had low scores. Analysis also showed a moderate to high statistically significant correlation between CVM and hand-wrist maturation methods. There was a moderate to high reproducibility of the CVM method, and only one specific study investigated the accuracy of the CVM index in detecting peak pubertal growth. This systematic review has shown that the studies on CVM method for radiographic assessment of skeletal maturation stages suffer from serious methodological failures. Better-designed studies with adequate accuracy, reproducibility, and correlation analysis, including studies with appropriate sensitivity-specificity analysis, should be performed.

Correlation between chronological age, cervical vertebral maturation and Fishman's skeletal maturity indicators in southern Chinese.

Science.gov (United States)

Alkhal, Hessa Abdulla; Wong, Ricky W K; Rabie, A Bakr M

2008-07-01

To investigate the correlation between chronological age, cervical vertebral maturation (CVM), and Fishman's hand-wrist skeletal maturity indicators in southern Chinese. Four hundred contemporary hand-wrist and lateral cephalometric radiographs of southern Chinese subjects were randomly selected and analyzed. The female subjects were between 10 and 15 years of age, and the male subjects were between 12 and 17 years of age; all subjects were within the circumpubertal period. The CVM was assessed using the method developed by Baccetti and coworkers, but the hand-wrist maturation was assessed using the method developed by Fishman. These two methods and the chronological age were correlated using the Spearman rank correlation analysis. The CVM was significantly correlated with the hand-wrist skeletal age (Spearman r male = 0.9206, female = 0.9363). All patients in the cervical maturation stage (CS3) of CVM were discovered to be in the skeletal maturational indicator (SMI2 or SMI3) stages of hand-wrist maturation (HWM), which was around the peak of the growth spurt. Low correlations were found between the CVM and chronological age (male r = 0.7577; female r = 0.7877) and between the HWM and chronological age (male r = 0.7492; female r = 0.7758). CVM is a valid indicator of skeletal growth during the circumpubertal and has a high correlation with the HWM for the southern Chinese population. However, the low correlations found between the chronological age and both CVM and HWM showed that the chronological age was not suitable to measure skeletal maturity.

Automating X-ray Fluorescence Analysis for Rapid Astrobiology Surveys.

Science.gov (United States)

Thompson, David R; Flannery, David T; Lanka, Ravi; Allwood, Abigail C; Bue, Brian D; Clark, Benton C; Elam, W Timothy; Estlin, Tara A; Hodyss, Robert P; Hurowitz, Joel A; Liu, Yang; Wade, Lawrence A

2015-11-01

A new generation of planetary rover instruments, such as PIXL (Planetary Instrument for X-ray Lithochemistry) and SHERLOC (Scanning Habitable Environments with Raman Luminescence for Organics and Chemicals) selected for the Mars 2020 mission rover payload, aim to map mineralogical and elemental composition in situ at microscopic scales. These instruments will produce large spectral cubes with thousands of channels acquired over thousands of spatial locations, a large potential science yield limited mainly by the time required to acquire a measurement after placement. A secondary bottleneck also faces mission planners after downlink; analysts must interpret the complex data products quickly to inform tactical planning for the next command cycle. This study demonstrates operational approaches to overcome these bottlenecks by specialized early-stage science data processing. Onboard, simple real-time systems can perform a basic compositional assessment, recognizing specific features of interest and optimizing sensor integration time to characterize anomalies. On the ground, statistically motivated visualization can make raw uncalibrated data products more interpretable for tactical decision making. Techniques such as manifold dimensionality reduction can help operators comprehend large databases at a glance, identifying trends and anomalies in data. These onboard and ground-side analyses can complement a quantitative interpretation. We evaluate system performance for the case study of PIXL, an X-ray fluorescence spectrometer. Experiments on three representative samples demonstrate improved methods for onboard and ground-side automation and illustrate new astrobiological science capabilities unavailable in previous planetary instruments. Dimensionality reduction-Planetary science-Visualization.

In Vitro Maturation and Embryo Development to blastocyst Mouse Germinal Vesicle Oocytes after Vitrification

Directory of Open Access Journals (Sweden)

M Nikseresht

2013-05-01

Full Text Available Abstract Background & aim: Vitrification is a simple and ultra rapid technique for the conservation of fertility. Improving pregnancy rate associate with the use of cryopreserved oocytes would be an important advanced in human assisted reproductive technology (ART. The purpose of this study was to evaluate survival, oocytes maturation and embryo development to the blastocyst stage after vitrification of oocytes germinal vesicle-stage and multi stage Methods: In the present experimental study, germinal vesicle oocytes with or without cumulus cells were transferred to vitrification solution containing 30% (v/v ethylene glycol, 18% (w/v Ficoll-70, and 0.3 M sucrose, either by single step or in a step-wise way. After vitrification and storage in liquid nitrogen, the oocytes were thawed and washed twice in culture medium TCM119, and then subjected to in vitro maturation, fertilization, and culture. Data analysis was performed by using One-way variance and Tukey tests. Results: Oocytes survival, metaphase 2 stage oocyte maturation, fertilization and embryo formed blastocyst in vitrification methods multistage were significantly higher than the single step procedure (P<0/05 Conclusion: The Germinal vesicle stage oocytes vitrified with cumulus cells and stepwise procedure had positive effect on the survival, maturation and developmental rate on blastocyst compared to oocytes without cumulus cell and single step procedure. Key words: Germinal Vesicle Oocyte, Blastocyst, Vitrification, Ethylene glycol

Establishment of a 10-Plex Quantitative Fluorescent-PCR Assay for rapid diagnosis of sex chromosome aneuploidies.

Directory of Open Access Journals (Sweden)

Xingmei Xie

Full Text Available Sex chromosome aneuploidies occur commonly in the general population, with an incidence of 1 in 400 newborns. However, no tests specifically targeting sex chromosomes have been carried out in prenatal diagnosis or newborn screening, resulting in late recognition of these diseases. In this study, a rapid diagnostic method for sex chromosome aneuploidies was established using Quantitative Fluorescent-PCR (QF-PCR. Ten markers were included in one multiplex QF-PCR assay, including two sex determination genes (AMXY and SRY, five X-linked short tandem repeats (STRs; DXS1053, DXS981, DXS6809, DXS1187, and DXS8377, one X/Y-common STR (X22, and two autosomal STRs (D13S305 and D21S11. Retrospective tests of 70 cases with known cytogenetic results indicated that the 10-plex QF-PCR assay could well determine sex chromosome copy numbers by both allelic peak numbers and a sex chromosome dosage calculation with the autosomal STRs as internal controls. Prospective comparison with cytogenetic karyotyping on 534 cases confirmed that the 10-plex QF-PCR assay could be well employed for sex chromosome aneuploidy diagnosis in at least the Chinese Han population. This is the first QF-PCR test for the diagnosis of sex chromosome aneuploidies in the Chinese population. This test is superior to previous designs by including up to 8 sex-linked markers covering different parts of sex chromosomes as well as employing internal controls for copy number dosage calculation in a single PCR reaction. Due to simple technique and data analysis, as well as easy implementation within routine clinical services, this method is of great clinical application value and could be widely applied.

Set-Theoretic Approach to Maturity Models

DEFF Research Database (Denmark)

Lasrado, Lester Allan

Despite being widely accepted and applied, maturity models in Information Systems (IS) have been criticized for the lack of theoretical grounding, methodological rigor, empirical validations, and ignorance of multiple and non-linear paths to maturity. This PhD thesis focuses on addressing...... these criticisms by incorporating recent developments in configuration theory, in particular application of set-theoretic approaches. The aim is to show the potential of employing a set-theoretic approach for maturity model research and empirically demonstrating equifinal paths to maturity. Specifically...... methodological guidelines consisting of detailed procedures to systematically apply set theoretic approaches for maturity model research and provides demonstrations of it application on three datasets. The thesis is a collection of six research papers that are written in a sequential manner. The first paper...

Highly sensitive and selective fluorescent assay for guanine based on the Cu2 +/eosin Y system

Science.gov (United States)

Shi, Huimin; Cui, Yi; Gong, Yijun; Feng, Suling

2016-05-01

A fluorescent probe has been developed for the determination of guanine based on the quenched fluorescence signal of Cu2 +/eosin Y. Cu2 + interacted with eosin Y, resulting in fluorescence quenching. Subsequently, with the addition of guanine to the Cu2 +/eosin Y system, guanine reacted with Cu2 + to form 1:1 chelate cation, which further combined with eosin Y to form a 1:1 ternary ion-association complex by electrostatic attraction and hydrophobic interaction, resulting in significant decrease of the fluorescence. Hence, a fluorescent system was constructed for rapid, sensitive and selective detection of guanine with a detection limit as low as 1.5 nmol L- 1 and a linear range of 3.3-116 nmol L- 1. The method has been applied satisfactorily to the determination of guanine in DNA and urine samples with the recoveries from 98.7% to 105%. This study significantly expands the realm of application of ternary ion-association complex in fluorescence probe.

A Novel Analytical Method for Trace Ammonium in Freshwater and Seawater Using 4-Methoxyphthalaldehyde as Fluorescent Reagent

Directory of Open Access Journals (Sweden)

Ying Liang

2015-01-01

Full Text Available A novel fluorescent reagent for determination of ammonium, 4-methoxyphthalaldehyde (MOPA, was successfully synthesized in this study. Under alkaline conditions, MOPA could reacted with ammonium rapidly at room temperature, producing fluorescent substance which had maximum excitation at 370 nm and emission wavelength at 454 nm. Based on this, a novel fluorescence analysis method was established for the determination of trace ammonium in natural water. Experimental parameters including reagent concentration, pH, reaction equilibrium time, and metal ions masking agent were optimized. The results showed that the optimized MOPA concentration was 0.12 g/L, pH was in the range of 11.2–12.0, and sulfite concentration was 0.051 g/L, respectively. Metal ions masking agent had no obvious effect on the fluorescence signal. With the reaction time of 15 minutes, linear range of this method was between 0.025 and 0.300 μmol/L, and the method detecting limit was 0.0058 μmol/L. The matrix recovery of the proposed method was in the range of 93.6–108.1%. Compared with the OPA method, this method was much more sensitive and rapid without the interference of background peak and would be more suitable for developing a portable fluorescence detection system.

Rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection.

Science.gov (United States)

Yang, Xiao; Diao, Chun-Peng; Sun, Ai-Ling; Liu, Ren-Min

2014-10-01

A method for the rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection was proposed in this paper. A simple apparatus consisting of a test tube and a cut-glass dropper was designed and applied to collect the floating extraction drop in liquid-liquid microextraction when low-density organic solvent was used as the extraction solvent. Solidification and melting steps that were tedious but necessary once the low-density organic solvent used as extraction solvent could be avoided by using this apparatus. Bisphenol A was selected as model pollutant and vortex-assisted liquid-liquid microextraction was employed to investigate the usefulness of the apparatus. High-performance liquid chromatography with fluorescence detection was selected as the analytical tool for the detection of bisphenol A. The linear dynamic range was from 0.10 to 100 μg/L for bisphenol A, with good squared regression coefficient (r(2) = 0.9990). The relative standard deviation (n = 7) was 4.7% and the limit of detection was 0.02 μg/L. The proposed method had been applied to the determination of bisphenol A in natural water samples and was shown to be economical, fast, and convenient. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advance in diagnosis of female genital tract tumor with laser fluorescence

Science.gov (United States)

Ding, Ai-Hua; Tseng, Quen; Lian, Shao-Hui

1998-11-01

In order to improve the diagnostic accuracy of malignant tumors with laser fluorescence, in 1996, our group successfully created the computerized laser fluorescence spectrograph type II with more reliable images shown overshadowing the naked eye method before 74 cases of female genital tract diseases had been examined by the LFS II resulting in 10 positive cases which were also proven pathologically as malignant tumors, without nay false negative, 3 cases presented suspicious positive but all were proven pathologically as non-tumors lesions, the false positive rate was 4 percent. Our work showed that the method of LFS II can provide a more rapid and accurate diagnosis for the clinical malignant tumors.

Detection of Salmonella typhi utilizing bioconjugated fluorescent polymeric nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Jain, Swati, E-mail: swatijain.iitd@gmail.com; Chattopadhyay, Sruti, E-mail: sruticiitd@gmail.com; Jackeray, Richa; Abid, Zainul; Singh, Harpal, E-mail: harpal2000@yahoo.com [Centre for Biomedical Engineering, Indian Institute of Technology-Delhi (India)

2016-05-15

Present work demonstrates effective utilization of functionalized polymeric fluorescent nanoparticles as biosensing probe for the detection of Salmonella typhi bacteria on modified polycarbonate (PC) filters in about 3 h. Antibody modified-PC membranes were incubated with contaminated bacterial water for selective capturing which were detected by synthesized novel bioconjugate probe. Core–shell architecture of polymeric nanoparticles endows them with aqueous stabilization and keto-enolic functionalities making them usable for covalently linking S. typhi antibodies without any crosslinker or activator. Bradford analysis revealed that one nanoparticle has an average of 3.51 × 10{sup −19} g or 21 × 10{sup 4} bound S. typhi Ab molecules. Analysis of the regions of interest (ROI) in fluorescent micrographs of modified fluoroimmunoassay showed higher detection sensitivity of 5 × 10{sup 2} cells/mL due to signal amplification unlike conventional naked dye FITC-Ab conjugate. Fluorescence of pyrene dye remained same on immobilization of biomolecules and nanoparticles showed stable fluorescent intensity under prolong exposure to laser owing to protective polymeric layer allowing accurate identification of bacteria. Surface-functionalized PC matrix and fluorescent label NPs permit covalent interactions among biomolecules enhancing signal acquisitions showing higher detection efficiency as compared to conventional microtiter plate-based system. Our novel immunoassay has the potential to be explored as rapid detection method for identifying S. typhi contaminations in water.Graphical Abstract.

Detection of Salmonella typhi utilizing bioconjugated fluorescent polymeric nanoparticles

International Nuclear Information System (INIS)

Jain, Swati; Chattopadhyay, Sruti; Jackeray, Richa; Abid, Zainul; Singh, Harpal

2016-01-01

Present work demonstrates effective utilization of functionalized polymeric fluorescent nanoparticles as biosensing probe for the detection of Salmonella typhi bacteria on modified polycarbonate (PC) filters in about 3 h. Antibody modified-PC membranes were incubated with contaminated bacterial water for selective capturing which were detected by synthesized novel bioconjugate probe. Core–shell architecture of polymeric nanoparticles endows them with aqueous stabilization and keto-enolic functionalities making them usable for covalently linking S. typhi antibodies without any crosslinker or activator. Bradford analysis revealed that one nanoparticle has an average of 3.51 × 10"−"1"9 g or 21 × 10"4 bound S. typhi Ab molecules. Analysis of the regions of interest (ROI) in fluorescent micrographs of modified fluoroimmunoassay showed higher detection sensitivity of 5 × 10"2 cells/mL due to signal amplification unlike conventional naked dye FITC-Ab conjugate. Fluorescence of pyrene dye remained same on immobilization of biomolecules and nanoparticles showed stable fluorescent intensity under prolong exposure to laser owing to protective polymeric layer allowing accurate identification of bacteria. Surface-functionalized PC matrix and fluorescent label NPs permit covalent interactions among biomolecules enhancing signal acquisitions showing higher detection efficiency as compared to conventional microtiter plate-based system. Our novel immunoassay has the potential to be explored as rapid detection method for identifying S. typhi contaminations in water.Graphical Abstract

In vitro acute exposure to DEHP affects oocyte meiotic maturation, energy and oxidative stress parameters in a large animal model.

Directory of Open Access Journals (Sweden)

Barbara Ambruosi

Full Text Available Phthalates are ubiquitous environmental contaminants because of their use in plastics and other common consumer products. Di-(2-ethylhexyl phthalate (DEHP is the most abundant phthalate and it impairs fertility by acting as an endocrine disruptor. The aim of the present study was to analyze the effects of in vitro acute exposure to DEHP on oocyte maturation, energy and oxidative status in the horse, a large animal model. Cumulus cell (CC apoptosis and oxidative status were also investigated. Cumulus-oocyte complexes from the ovaries of slaughtered mares were cultured in vitro in presence of 0.12, 12 and 1200 µM DEHP. After in vitro maturation (IVM, CCs were removed and evaluated for apoptosis (cytological assessment and TUNEL and intracellular reactive oxygen species (ROS levels. Oocytes were evaluated for nuclear chromatin configuration. Matured (Metaphase II stage; MII oocytes were further evaluated for cytoplasmic energy and oxidative parameters. DEHP significantly inhibited oocyte maturation when added at low doses (0.12 µM; P<0.05. This effect was related to increased CC apoptosis (P<0.001 and reduced ROS levels (P<0.0001. At higher doses (12 and 1200 µM, DEHP induced apoptosis (P<0.0001 and ROS increase (P<0.0001 in CCs without affecting oocyte maturation. In DEHP-exposed MII oocytes, mitochondrial distribution patterns, apparent energy status (MitoTracker fluorescence intensity, intracellular ROS localization and levels, mt/ROS colocalization and total SOD activity did not vary, whereas increased ATP content (P<0.05, possibly of glycolytic origin, was found. Co-treatment with N-Acetyl-Cysteine reversed apoptosis and efficiently scavenged excessive ROS in DEHP-treated CCs without enhancing oocyte maturation. In conclusion, acute in vitro exposure to DEHP inhibits equine oocyte maturation without altering ooplasmic energy and oxidative stress parameters in matured oocytes which retain the potential to be fertilized and develop into

In vitro acute exposure to DEHP affects oocyte meiotic maturation, energy and oxidative stress parameters in a large animal model.

Science.gov (United States)

Ambruosi, Barbara; Uranio, Manuel Filioli; Sardanelli, Anna Maria; Pocar, Paola; Martino, Nicola Antonio; Paternoster, Maria Stefania; Amati, Francesca; Dell'Aquila, Maria Elena

2011-01-01

Phthalates are ubiquitous environmental contaminants because of their use in plastics and other common consumer products. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate and it impairs fertility by acting as an endocrine disruptor. The aim of the present study was to analyze the effects of in vitro acute exposure to DEHP on oocyte maturation, energy and oxidative status in the horse, a large animal model. Cumulus cell (CC) apoptosis and oxidative status were also investigated. Cumulus-oocyte complexes from the ovaries of slaughtered mares were cultured in vitro in presence of 0.12, 12 and 1200 µM DEHP. After in vitro maturation (IVM), CCs were removed and evaluated for apoptosis (cytological assessment and TUNEL) and intracellular reactive oxygen species (ROS) levels. Oocytes were evaluated for nuclear chromatin configuration. Matured (Metaphase II stage; MII) oocytes were further evaluated for cytoplasmic energy and oxidative parameters. DEHP significantly inhibited oocyte maturation when added at low doses (0.12 µM; P<0.05). This effect was related to increased CC apoptosis (P<0.001) and reduced ROS levels (P<0.0001). At higher doses (12 and 1200 µM), DEHP induced apoptosis (P<0.0001) and ROS increase (P<0.0001) in CCs without affecting oocyte maturation. In DEHP-exposed MII oocytes, mitochondrial distribution patterns, apparent energy status (MitoTracker fluorescence intensity), intracellular ROS localization and levels, mt/ROS colocalization and total SOD activity did not vary, whereas increased ATP content (P<0.05), possibly of glycolytic origin, was found. Co-treatment with N-Acetyl-Cysteine reversed apoptosis and efficiently scavenged excessive ROS in DEHP-treated CCs without enhancing oocyte maturation. In conclusion, acute in vitro exposure to DEHP inhibits equine oocyte maturation without altering ooplasmic energy and oxidative stress parameters in matured oocytes which retain the potential to be fertilized and develop into embryos

Dansyl-Galactoside, a Fluorescent Probe of Active Transport in Bacterial Membrane Vesicles*

Science.gov (United States)

Reeves, John P.; Shechter, Emanuel; Weil, Rudolf; Kaback, H. R.

1973-01-01

A fluorescent galactoside, 2-(N-dansyl)-aminoethyl β-D-thiogalactoside (dansyl-galactoside), competitively inhibits lactose transport by membrane vesicles of Escherichia coli, but is not actively transported. An increase in dansyl-galactoside fluorescence is observed upon addition of D-lactate. The fluorescence increase is not observed in membrane vesicles lacking the β-galactoside transport system, and is blocked or rapidly reversed by addition of β-galactosides, sulfhydryl reagents, inhibitors of D-lactate oxidation, or uncoupling agents. The fluorescence increase exhibits an emission maximum at 500 nm and excitation maxima at 345 nm and at 292 nm. The latter excitation maximum is absent unless D-lactate is added, indicating that the bound dansyl-galactoside molecules are excited by energy transfer from the membrane proteins. Titration of vesicles with dansyl-galactoside in the presence of D-lactate demonstrates that the β-galactoside carrier protein represents about 3.3% of the total membrane protein. The data indicate that D-lactate oxidation leads to binding of the fluorescent galactoside to the β-galactoside carrier protein in such a manner that the dansyl group is transferred to a hydrophobic environment within the membrane. PMID:4583021

Highly selective and sensitive fluorescent chemosensor for femtomolar detection of silver ion in aqueous medium

OpenAIRE

Arulraj, Abraham Daniel; Devasenathipathy, Rajkumar; Chen, Shen-Ming; Vasantha, Vairathevar Sivasamy; Wang, Sea-Fue

2015-01-01

The chemical sensing for the trace level detection of silver ion in aqueous solution still remains a challenge using simple, rapid, and inexpensive method. We report that thionine can be used as a fluorescent probe for the detection of Ag+ ion. The successive addition of Ag+ ion to the solution containing thionine quenches (turns-off) the fluorescence intensity of thionine. Association and quenching constants have been estimated by the Benesi–Hildebrand method and Stern–Volmer plot, respectiv...

Diversity and evolution of coral fluorescent proteins.

Directory of Open Access Journals (Sweden)

Naila O Alieva

2008-07-01

Full Text Available GFP-like fluorescent proteins (FPs are the key color determinants in reef-building corals (class Anthozoa, order Scleractinia and are of considerable interest as potential genetically encoded fluorescent labels. Here we report 40 additional members of the GFP family from corals. There are three major paralogous lineages of coral FPs. One of them is retained in all sampled coral families and is responsible for the non-fluorescent purple-blue color, while each of the other two evolved a full complement of typical coral fluorescent colors (cyan, green, and red and underwent sorting between coral groups. Among the newly cloned proteins are a "chromo-red" color type from Echinopora forskaliana (family Faviidae and pink chromoprotein from Stylophora pistillata (Pocilloporidae, both evolving independently from the rest of coral chromoproteins. There are several cyan FPs that possess a novel kind of excitation spectrum indicating a neutral chromophore ground state, for which the residue E167 is responsible (numeration according to GFP from A. victoria. The chromoprotein from Acropora millepora is an unusual blue instead of purple, which is due to two mutations: S64C and S183T. We applied a novel probabilistic sampling approach to recreate the common ancestor of all coral FPs as well as the more derived common ancestor of three main fluorescent colors of the Faviina suborder. Both proteins were green such as found elsewhere outside class Anthozoa. Interestingly, a substantial fraction of the all-coral ancestral protein had a chromohore apparently locked in a non-fluorescent neutral state, which may reflect the transitional stage that enabled rapid color diversification early in the history of coral FPs. Our results highlight the extent of convergent or parallel evolution of the color diversity in corals, provide the foundation for experimental studies of evolutionary processes that led to color diversification, and enable a comparative analysis of

Post-mortem re-cloning of a transgenic red fluorescent protein dog.

Science.gov (United States)

Hong, So Gun; Koo, Ok Jae; Oh, Hyun Ju; Park, Jung Eun; Kim, Minjung; Kim, Geon-A; Park, Eun Jung; Jang, Goo; Lee, Byeong-Chun

2011-12-01

Recently, the world's first transgenic dogs were produced by somatic cell nuclear transfer. However, cellular senescence is a major limiting factor for producing more advanced transgenic dogs. To overcome this obstacle, we rejuvenated transgenic cells using a re-cloning technique. Fibroblasts from post-mortem red fluorescent protein (RFP) dog were reconstructed with in vivo matured oocytes and transferred into 10 surrogate dogs. One puppy was produced and confirmed as a re-cloned dog. Although the puppy was lost during birth, we successfully established a rejuvenated fibroblast cell line from this animal. The cell line was found to stably express RFP and is ready for additional genetic modification.

Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system.

Science.gov (United States)

Mounier, S; Nicolodelli, G; Redon, R; Milori, D M B P

2017-04-15

The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model. Copyright © 2017 Elsevier B.V. All rights reserved.

Sensitive determination of nucleic acids using organic nanoparticle fluorescence probes

Science.gov (United States)

Zhou, Yunyou; Bian, Guirong; Wang, Leyu; Dong, Ling; Wang, Lun; Kan, Jian

2005-06-01

This paper describes the preparation of organic nanoparticles by reprecipitation method under sonication and vigorous stirring. Transmission electron microscopy (TEM) was used to characterize the size and size distribution of the luminescent nanoparticles. Their average diameter was about 25 nm with a size variation of ±18%. The fluorescence decay lifetime of the nanoparticles also was determined on a self-equipped fluorospectrometer with laser light source. The lifetime (˜0.09 μs) of nanoparticles is about three times long as that of the monomer. The nanoparticles were in abundant of hydrophilic groups, which increased their miscibility in aqueous solution. These organic nanoparticles have high photochemical stability, excellent resistance to chemical degradation and photodegradation, and a good fluorescence quantum yield (25%). The fluorescence can be efficiently quenched by nucleic acids. Based on the fluorescence quenching of nanoparticles, a fluorescence quenching method was developed for determination of microamounts of nucleic acids by using the nanoparticles as a new fluorescent probe. Under optimal conditions, maximum fluorescence quenching is produced, with maximum excitation and emission wavelengths of 345 and 402 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range 0.4-19.0 μg ml -1 for calf thymus DNA (ct-DNA) and 0.3-19.0 μg ml -1 for fish sperm DNA (fs-DNA). The corresponding detection limits are 0.25 μg ml -1 for ct-DNA and 0.17 μg ml -1 for fs-DNA. The relative standard deviation of six replicate measurements is 1.3-2.1%. The method is simple, rapid and sensitive with wide linear range. The recovery and relative standard deviation are very satisfactory.

Influence of plant maturity, shoot reproduction and sex on vegetative growth in the dioecious plant Urtica dioica.

Science.gov (United States)

Oñate, Marta; Munné-Bosch, Sergi

2009-10-01

Stinging nettle (Urtica dioica) is a herbaceous, dioecious perennial that is widely distributed around the world, reproduces both sexually and asexually, and is characterized by rapid growth. This work was aimed at evaluating the effects of plant maturity, shoot reproduction and sex on the growth of leaves and shoots. Growth rates of apical shoots, together with foliar levels of phytohormones (cytokinins, auxins, absicisic acid, jasmonic acid and salicylic acid) and other indicators of leaf physiology (water contents, photosynthetic pigments, alpha-tocopherol and F(v)/F(m) ratios) were measured in juvenile and mature plants, with a distinction made between reproductive and non-reproductive shoots in both males and females. Vegetative growth rates were not only evaluated in field-grown plants, but also in cuttings obtained from these plants. All measurements were performed during an active vegetative growth phase in autumn, a few months after mature plants reproduced during spring and summer. Vegetative growth rates in mature plants were drastically reduced compared with juvenile ones (48 % and 78 % for number of leaves and leaf biomass produced per day, respectively), which was associated with a loss of photosynthetic pigments (up to 24 % and 48 % for chlorophylls and carotenoids, respectively) and increases of alpha-tocopherol (up to 2.7-fold), while endogenous levels of phytohormones did not differ between mature and juvenile plants. Reductions in vegetative growth were particularly evident in reproductive shoots of mature plants, and occurred similarly in both males and females. It is concluded that (a) plant maturity reduces vegetative growth in U. dioica, (b) effects of plant maturity are evident both in reproductive and non-reproductive shoots, but particularly in the former, and (c) these changes occur similarly in both male and female plants.

Application of GIS Rapid Mapping Technology in Disaster Monitoring

Science.gov (United States)

Wang, Z.; Tu, J.; Liu, G.; Zhao, Q.

2018-04-01

With the rapid development of GIS and RS technology, especially in recent years, GIS technology and its software functions have been increasingly mature and enhanced. And with the rapid development of mathematical statistical tools for spatial modeling and simulation, has promoted the widespread application and popularization of quantization in the field of geology. Based on the investigation of field disaster and the construction of spatial database, this paper uses remote sensing image, DEM and GIS technology to obtain the data information of disaster vulnerability analysis, and makes use of the information model to carry out disaster risk assessment mapping.Using ArcGIS software and its spatial data modeling method, the basic data information of the disaster risk mapping process was acquired and processed, and the spatial data simulation tool was used to map the disaster rapidly.

Topically applied methotrexate is rapidly delivered into skin by fractional laser ablation

DEFF Research Database (Denmark)

Taudorf, Elisabeth Hjardem; Lerche, Catharina; Vissing, Anne-Cathrine

2015-01-01

Objectives: Methotrexate (MTX) is a chemotherapeutic and anti-inflammatory drug that may cause systemic adverse effects. This study investigated kinetics and biodistribution of MTX delivered topically by ablative fractional laser (AFXL). Methods: In vitro passive diffusion of 10 mg/ml MTX (1 w...... sections, donor and receiver compartments. Fluorescence microscopy of UVC-activated MTX-fluorescence and desorption electro-spray ionization mass spectrometry imaging (DESI-MSI) evaluated MTX biodistribution. Results: AFXL-processed skin facilitated rapid MTX delivery through cone-shaped microchannels.......30 mg/cm3, p = 0.002). Transdermal permeation was

Simple, rapid, and sensitive liquid chromatography-fluorescence method for the quantification of tranexamic acid in blood

NARCIS (Netherlands)

Huertas-Pérez, José Fernando; Heger, Michal; Dekker, Henk; Krabbe, Hans; Lankelma, Jan; Ariese, Freek

2007-01-01

Tranexamic acid (TA) is a synthetic antifibrinolytic agent that is being considered as a candidate adjuvant drug for site-specific pharmaco-laser therapy of port wine stains. For drug utility studies, a high-performance liquid chromatography (HPLC)-fluorescence method was developed for the

Thumb Ossification Composite Index (TOCI) for Predicting Peripubertal Skeletal Maturity and Peak Height Velocity in Idiopathic Scoliosis: A Validation Study of Premenarchal Girls with Adolescent Idiopathic Scoliosis Followed Longitudinally Until Skeletal Maturity.

Science.gov (United States)

Hung, Alec L H; Chau, W W; Shi, B; Chow, Simon K; Yu, Fiona Y P; Lam, T P; Ng, Bobby K W; Qiu, Y; Cheng, Jack C Y

2017-09-06

Accurate skeletal maturity assessment is important to guide clinical evaluation of idiopathic scoliosis, but commonly used methods are inadequate or too complex for rapid clinical use. The objective of the study was to propose a new simplified staging method, called the thumb ossification composite index (TOCI), based on the ossification pattern of the 2 thumb epiphyses and the adductor sesamoid bone; to determine its accuracy in predicting skeletal maturation when compared with the Sanders simplified skeletal maturity system (SSMS); and to validate its interrater and intrarater reliability. Hand radiographs of 125 girls, acquired when they were newly diagnosed with idiopathic scoliosis prior to menarche and during longitudinal follow-up until skeletal maturity (a minimum of 4 years), were scored with the TOCI and SSMS. These scores were compared with digital skeletal age (DSA) and radius, ulna, and small hand bones (RUS) scores; anthropometric data; peak height velocity; and growth-remaining profiles. Correlations were analyzed with the chi-square test, Spearman and Cramer V correlation methods, and receiver operating characteristic curve analysis. Reliability analysis using the intraclass correlation (ICC) was conducted. Six hundred and forty-five hand radiographs (average, 5 of each girl) were scored. The TOCI staging system was highly correlated with the DSA and RUS scores (r = 0.93 and 0.92, p systems predicted peak height velocity with comparable accuracy, with a strong Cramer V association (0.526 and 0.466, respectively; p 0.97. The new proposed TOCI could provide a simplified staging system for the assessment of skeletal maturity of subjects with idiopathic scoliosis. The index needs to be subjected to further multicenter validation in different ethnic groups.

Fluorescence spectroscopy

DEFF Research Database (Denmark)

Bagatolli, Luis

2016-01-01

Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses the foundati......Fluorescence spectroscopy is a powerful experimental tool used by scientists from many disciplines. During the last decades there have been important developments on distinct fluorescence methods, particularly those related to the study of biological phenomena. This chapter discusses...

Effect of carbon and nitrogen assimilation on chlorophyll fluorescence emission by the cyanobacterium Anacystis nidulans

Energy Technology Data Exchange (ETDEWEB)

Romero, J.M.; Lara, C. (Instituto de Bioquimica Vegetal y Fotosintesis, Univ. de Sevilla y CSIC, Sevilla (ES)); Sivak, M.N. (Dept. of Biochemistry, Michigan State Univ., East Lansing (US))

1992-01-01

O{sub 2} evolution and chlorophyll A fluorescence emission have been monitored in intact cells of the cyanobacterium Anacystis nidulans 1402-1 to study the influence of carbon and nitrogen assimilation on the operation of the photosynthetic apparatus. The pattern of fluorescence induction in dark-adapted cyanobacterial cells was different from that of higher plants. Cyanobacteria undergo large, rapid state transitions upon illumination, which lead to marked changes in the fluorescence yield, complicating the estimation of quenching coefficients. The Kautsky effect was not evident, although it could be masked by a state II-state I transition, upon illumination with actinic light. The use of inhibitors of carbon assimilation such as D,L-glyceraldehyde or iodoacetamide allowed us to relate changes in variable fluorescence to active CO{sub 2} fixation. Ammonium, but not nitrate, induced non-photochemical fluorescence quenching, in agreement with a previous report on green algae, indicative of an ammonium-induced state i transition. (au).

Fluorescence imaging to quantify crop residue cover

Science.gov (United States)

Daughtry, C. S. T.; Mcmurtrey, J. E., III; Chappelle, E. W.

1994-01-01

Crop residues, the portion of the crop left in the field after harvest, can be an important management factor in controlling soil erosion. Methods to quantify residue cover are needed that are rapid, accurate, and objective. Scenes with known amounts of crop residue were illuminated with long wave ultraviolet (UV) radiation and fluorescence images were recorded with an intensified video camera fitted with a 453 to 488 nm band pass filter. A light colored soil and a dark colored soil were used as background for the weathered soybean stems. Residue cover was determined by counting the proportion of the pixels in the image with fluorescence values greater than a threshold. Soil pixels had the lowest gray levels in the images. The values of the soybean residue pixels spanned nearly the full range of the 8-bit video data. Classification accuracies typically were within 3(absolute units) of measured cover values. Video imaging can provide an intuitive understanding of the fraction of the soil covered by residue.

Changes in primary metabolites and polyphenols in the peel of "Braeburn" apples (Malus domestica Borkh.) during advanced maturation.

Science.gov (United States)

Bizjak, Jan; Mikulic-Petkovsek, Maja; Stampar, Franci; Veberic, Robert

2013-10-30

During the two growing seasons the evolution of primary metabolites and wide range of polyphenols in the "Braeburn" apple peel during advanced maturation were investigated. During the five weeks sucrose significantly increased, whereas fructose and glucose fluctuated around the same level in one season and decreased in another. Regarding malic and citric acids, an expected decrease was recorded. The concentrations of hydroxycinnamic acids, dihydrochalcones, and flavanols remained quite constant or slightly decreased during advanced apple ripening. On the contrary an intensive accumulation of quercetin glycosides and anthocyanins took place during this period, starting with the onset of rapid formation approximately 3 weeks before the technological maturity of apples. Total phenolic content was relatively constant or slightly increased. The present results suggest that measures designed to improve the apple color and quality of "Braeburn" apples should be performed approximately 3-4 weeks before the expected technological maturity of apples.

Sustaining Exploration in Mature Basins

International Nuclear Information System (INIS)

Bayo, A.

2002-01-01

Exploration is a business like any other business driven by opportunity, resources and expectation of profit. Therefore, exploration will thrive anywhere the opportunities are significant, the resources are available and the outlook for profit (or value creation) is good. To sustain exploration activities anywhere, irrespective of the environment, there must be good understanding of the drivers of these key investment criteria. This paper will examine these investment criteria as they relate to exploration business and address the peculiarity of exploration in mature basin. Mature basins are unique environment that lends themselves a mix of fears, paradigms and realities, particularly with respect to the perception of value. To sustain exploration activities in a mature basin, we need to understand these perceptions relative to the true drivers of profitability. Exploration in the mature basins can be as profitable as exploration in emerging basins if the dynamics of value definition-strategic and fiscal values are understood by operators, regulators and co ventures alike. Some suggestions are made in this presentation on what needs to be done in addressing these dynamic investment parameters and sustaining exploration activities in mature basins

A highly sensitive, selective and turn-off fluorescent sensor based on phenylamine-oligothiophene derivative for rapid detection of Hg{sup 2+}

Energy Technology Data Exchange (ETDEWEB)

Wu, Xingxing; Niu, Qingfen, E-mail: qf_niu1216@qlu.edu.cn; Li, Tianduo; Cui, Yuezhi; Zhang, Shanshan

2016-07-15

A fluorescent sensor based on phenylamine-oligothiophene derivative 3TEA was reported. This sensor showed highly selective and sensitive detection of Hg{sup 2+} ion in THF/H{sub 2}O (7/3, v/v) solution through fluorescence quenching. The detection was unaffected by other competitive metal ions. The detection limit was found to be as low as 3.952×10{sup −7} M estimated by the titration method. The recognition process is reversible and confirmed by EDTA experiment. The turn-off fluorescence behavior of mercury interaction with 3TEA has been found to be so fast that it can be used for its qualitative as well as quantitative estimation. - Highlights: • A highly sensitive and selective fluorescence chemosensor 3TEA was reported. • 3TEA features high sensitive with the detection limit for Hg{sup 2+} ions was as low as 3.952×10{sup −7} M. • 3TEA can detect Hg{sup 2+} ion on-line and in real time.

Acute toxicity of excess mercury on the photosynthetic performance of cyanobacterium, S. platensis--assessment by chlorophyll fluorescence analysis.

Science.gov (United States)

Lu, C M; Chau, C W; Zhang, J H

2000-07-01

Measurement of chlorophyll fluorescence has been shown to be a rapid, non-invasive, and reliable method to assess photosynthetic performance in a changing environment. In this study, acute toxicity of excess Hg on the photosynthetic performance of the cyanobacterium S. platensis, was investigated by use of chlorophyll fluorescence analysis after cells were exposed to excess Hg (up to 20 microM) for 2 h. The results determined from the fast fluorescence kinetics showed that Hg induced a significant increase in the proportion of the Q(B)-non-reducing PSII reaction centers. The fluorescence parameters measured under the steady state of photosynthesis demonstrated that the increase of Hg concentration led to a decrease in the maximal efficiency of PSII photochemistry, the efficiency of excitation energy capture by the open PSII reaction centers, and the quantum yield of PSII electron transport. Mercury also resulted in a decrease in the coefficients of photochemical and non-photochemical quenching. Mercury may have an acute toxicity on cyanobacteria by inhibiting the quantum yield of photosynthesis sensitively and rapidly. Such changes occurred before any other visible damages that may be evaluated by other conventional measurements. Our results also demonstrated that chlorophyll fluorescence analysis can be used as a useful physiological tool to assess early stages of change in photosynthetic performance of algae in response to heavy metal pollution.

Bodipy-FL-Verapamil: A Fluorescent Probe for the Study of Multidrug Resistance Proteins

Directory of Open Access Journals (Sweden)

Anna Rosati

2004-01-01

Full Text Available Most of the substances used as fluorescent probes to study drug transport and the effect of efflux blockers in multidrug resistant cells have many drawbacks, such as toxicity, unspecific background, accumulation in mitochondria. New fluorescent compounds, among which Bodipy‐FL‐verapamil (BV, have been therefore proposed as more useful tools. The uptake of BV has been evaluated by cytofluorimetry and fluorescence microscopy using cell lines that overexpress P‐glycoprotein (P388/ADR and LLC‐PK1/ADR or MRP (multidrug resistance‐related protein (PANC‐1 and clinical specimens from patients. The effect of specific inhibitors for P‐glycoprotein (verapamil and vinblastine or MRP (MK571 and probenecid has been also studied. BV intracellular concentrations were significantly lower in the two P‐glycoprotein overexpressing cell lines in comparison with the parental lines. In addition, verapamil and vinblastine increased the intracellular concentrations of the dye; MK571 and probenecid, two MRP inhibitors, increased BV levels in PANC‐1 cells, that express this protein. These findings were confirmed in clinical specimens from patients. Fluorescence microscopy revealed a faint fluorescence emission in P‐glycoprotein or MRP expressing cell lines; however, treatment with specific inhibitors significantly increased the fluorescence. BV is a useful tool for studying multidrug resistance proteins with different techniques such as cytofluorimetry and fluorescence microscopy, but does not discriminate between P‐glycoprotein and MRP. In comparison with other classic fluorescent probes, the assay with this dye is extremely rapid, simple, not toxic for cells, devoid of fluorescent background, and can be useful in the clinical settings.

Fluorescent assay for oxytetracycline based on a long-chain aptamer assembled onto reduced graphene oxide

Energy Technology Data Exchange (ETDEWEB)

Zhao, Huimin; Gao, Sheng; Liu, Meng; Chang, Yangyang; Fan, Xinfei; Quan, Xie [Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, 116024 (China)

2013-07-15

We report on a fluorescent assay for oxytetracycline (OTC) using a fluorescein-labeled long-chain aptamer assembled onto reduced graphene oxide (rGO). The π-π stacking interaction between aptamer and rGO causes the fluorescence of the label to be almost completely quenched via energy transfer so that the system has very low background fluorescence. The addition of OTC leads to the formation of G-quadruplex OTC complexes and prevents the adsorption of labeled aptamer on the surface of rGO. As a result, fluorescence is restored, and this effect allows for a quantitative assay of OTC over the 0.1–2 μM concentration range and with a detection limit of 10 nM. This method is simple, rapid, selective and sensitive. It may be applied to other small molecule analytes by applying appropriate aptamers. (author)

Fluorescent assay for oxytetracycline based on a long-chain aptamer assembled onto reduced graphene oxide

International Nuclear Information System (INIS)

Zhao, Huimin; Gao, Sheng; Liu, Meng; Chang, Yangyang; Fan, Xinfei; Quan, Xie

2013-01-01

We report on a fluorescent assay for oxytetracycline (OTC) using a fluorescein-labeled long-chain aptamer assembled onto reduced graphene oxide (rGO). The π-π stacking interaction between aptamer and rGO causes the fluorescence of the label to be almost completely quenched via energy transfer so that the system has very low background fluorescence. The addition of OTC leads to the formation of G-quadruplex OTC complexes and prevents the adsorption of labeled aptamer on the surface of rGO. As a result, fluorescence is restored, and this effect allows for a quantitative assay of OTC over the 0.1–2 μM concentration range and with a detection limit of 10 nM. This method is simple, rapid, selective and sensitive. It may be applied to other small molecule analytes by applying appropriate aptamers. (author)

Confocal fluorescence microscopy for rapid evaluation of invasive tumor cellularity of inflammatory breast carcinoma core needle biopsies.

Science.gov (United States)

Dobbs, Jessica; Krishnamurthy, Savitri; Kyrish, Matthew; Benveniste, Ana Paula; Yang, Wei; Richards-Kortum, Rebecca

2015-01-01

Tissue sampling is a problematic issue for inflammatory breast carcinoma, and immediate evaluation following core needle biopsy is needed to evaluate specimen adequacy. We sought to determine if confocal fluorescence microscopy provides sufficient resolution to evaluate specimen adequacy by comparing invasive tumor cellularity estimated from standard histologic images to invasive tumor cellularity estimated from confocal images of breast core needle biopsy specimens. Grayscale confocal fluorescence images of breast core needle biopsy specimens were acquired following proflavine application. A breast-dedicated pathologist evaluated invasive tumor cellularity in histologic images with hematoxylin and eosin staining and in grayscale and false-colored confocal images of cores. Agreement between cellularity estimates was quantified using a kappa coefficient. 23 cores from 23 patients with suspected inflammatory breast carcinoma were imaged. Confocal images were acquired in an average of less than 2 min per core. Invasive tumor cellularity estimated from histologic and grayscale confocal images showed moderate agreement by kappa coefficient: κ = 0.48 ± 0.09 (p confocal images require less than 2 min for acquisition and allow for evaluation of invasive tumor cellularity in breast core needle biopsy specimens with moderate agreement to histologic images. We show that confocal fluorescence microscopy can be performed immediately following specimen acquisition and could indicate the need for additional biopsies at the initial visit.

Rotational multispectral fluorescence lifetime imaging and intravascular ultrasound: bimodal system for intravascular applications

Science.gov (United States)

Ma, Dinglong; Bec, Julien; Yankelevich, Diego R.; Gorpas, Dimitris; Fatakdawala, Hussain; Marcu, Laura

2014-01-01

Abstract. We report the development and validation of a hybrid intravascular diagnostic system combining multispectral fluorescence lifetime imaging (FLIm) and intravascular ultrasound (IVUS) for cardiovascular imaging applications. A prototype FLIm system based on fluorescence pulse sampling technique providing information on artery biochemical composition was integrated with a commercial IVUS system providing information on artery morphology. A customized 3-Fr bimodal catheter combining a rotational side-view fiberoptic and a 40-MHz IVUS transducer was constructed for sequential helical scanning (rotation and pullback) of tubular structures. Validation of this bimodal approach was conducted in pig heart coronary arteries. Spatial resolution, fluorescence detection efficiency, pulse broadening effect, and lifetime measurement variability of the FLIm system were systematically evaluated. Current results show that this system is capable of temporarily resolving the fluorescence emission simultaneously in multiple spectral channels in a single pullback sequence. Accurate measurements of fluorescence decay characteristics from arterial segments can be obtained rapidly (e.g., 20 mm in 5 s), and accurate co-registration of fluorescence and ultrasound features can be achieved. The current finding demonstrates the compatibility of FLIm instrumentation with in vivo clinical investigations and its potential to complement conventional IVUS during catheterization procedures. PMID:24898604

Ruminal acidosis and the rapid onset of ruminal parakeratosis in a mature dairy cow: a case report

OpenAIRE

Croom Jim; Hook Sarah E; AlZahal Ousama; Steele Michael A; McBride Brian W

2009-01-01

Abstract A mature dairy cow was transitioned from a high forage (100% forage) to a high-grain (79% grain) diet over seven days. Continuous ruminal pH recordings were utilized to diagnose the severity of ruminal acidosis. Additionally, blood and rumen papillae biopsies were collected to describe the structural and functional adaptations of the rumen epithelium. On the final day of the grain challenge, the daily mean ruminal pH was 5.41 ± 0.09 with a minimum of 4.89 and a maximum of 6.31. Rumin...

A rapid method for the determination of dopamine in porcine muscle by pre-column derivatization and HPLC with fluorescence detection

Directory of Open Access Journals (Sweden)

Hong-Xia Zhao

2011-08-01

Full Text Available A rapid method has been developed based on the sample preparation procedure named as QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe, combined with reversed-phase high performance liquid chromatography with fluorescence detector and C18 column after pre-column derivatization using o-phthalaldehyde and 2-mercaptoethanol to determine dopamine in porcine muscle. Methanol and deionized water (0.1% acetic acid, v/v with a ratio of 60:40 was used as mobile phase. The flow rate was 0.8 mL/min and dopamine was eluted within 15 min. The linearity range was 0.003–8 μg/mL with r=0.9992. The detection limit for dopamine was 4 μg/kg and the quantification limit was 9 μg/kg. Recovery studies were carried out at 0.1, 0.5 and 1.0 mg/kg fortification levels and the average recoveries obtained ranged from 90.4% to 98.2% with relative standard deviations between 3.5% and 8.1%. The method was found to be suitable for detection of dopamine in animal product tissues at the maximum residue level. Keywords: Liquid chromatography, Dopamine, o-phthalaldehyde, QuEChERS

Three-dimensional prospective evaluation of tooth-borne and bone-borne surgically assisted rapid maxillary expansion

NARCIS (Netherlands)

Nada, R.M.; Fudalej, P.S.; Maal, T.J.J.; Berge, S.J.; Mostafa, Y.A.; Kuijpers-Jagtman, A.M.

2012-01-01

AIM: To three-dimensionally (3D) assess the long-term effects of tooth-borne and bone-borne surgically assisted rapid maxillary expansion (SARME). SUBJECTS AND METHODS: This prospective cohort study comprised 45 consecutive skeletally mature non-syndromic patients with transverse maxillary

Characterization of the photoreaction between DNA and aminomethyl-trimethylpsoralen using absorption and fluorescence spectroscopy

International Nuclear Information System (INIS)

Johnston, B.H.; Hearst, J.E.

1981-01-01

The use of absorption and fluorescence spectroscopy for following the progress of the photoreaction between DNA and 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT) has been investigated. Absorption at long wavelengths and fluorescence both decline upon intercalation of AMT into the DNA helix. The loss of fluorescence from AMT and the accompanying appearance of monoadduct fluorescence upon irradiation by UV light can be easily followed by using the excitation beam of a spectrofluorometer as the source of irradiation and monitoring the changing emission spectrum. Where cross-link formation is possible, the subsequent decline of monoadduct fluorescence is seen as well. This suggests that the 4',5'-monoadduct is a precursor of cross-links. Both monoaddition and cross-linking are more rapid with poly d(A-T) than with calf thymus DNA or poly d(A.T). Excitation spectra can be helpful in resolving the levels of AMT and 4',5'-monoadduct when both are contributing to the emission spectrum. Some changes are observed in the emission spectrum of AMT-poly d(A.T) monoadducts after prolonged irradiation which indicate further photoreaction. (author)

Fused oblique incidence reflectometry and confocal fluorescence microscopy

Science.gov (United States)

Risi, Matthew D.; Rouse, Andrew R.; Gmitro, Arthur F.

2011-03-01

Confocal microendoscopy provides real-time high resolution cellular level images via a minimally invasive procedure, but relies on exogenous fluorophores, has a relatively limited penetration depth (100 μm) and field of view (700 μm), and produces a high rate of detailed information to the user. A new catheter based multi-modal system has been designed that combines confocal imaging and oblique incidence reflectometry (OIR), which is a non-invasive method capable of rapidly extracting tissue absorption, μa, and reduced scattering, μ's, spectra from tissue. The system builds on previous developments of a custom slit-scan multi-spectral confocal microendoscope and is designed to rapidly switch between diffuse spectroscopy and confocal fluorescence imaging modes of operation. An experimental proof-of-principle catheter has been developed that consists of a fiber bundle for traditional confocal fluorescence imaging and a single OIR source fiber which is manually redirected at +/- 26 degrees. Diffusely scattered light from each orientation of the source fiber is collected via the fiber bundle, with a frame of data representing spectra collected at a range of distances from the OIR source point. Initial results with intralipid phantoms show good agreement to published data over the 550-650 nm spectral range. We successfully imaged and measured the optical properties of rodent cardiac muscle.

[Application of rapid PCR to authenticate medicinal snakes].

Science.gov (United States)

Chen, Kang; Jiang, Chao; Yuan, Yuan; Huang, Lu-Qi; Li, Man

2014-10-01

To obtained an accurate, rapid and efficient method for authenticate medicinal snakes listed in Chinese Pharmacopoeia (Zaocysd humnades, Bungarus multicinctus, Agkistrodon acutus), a rapid PCR method for authenticate snakes and its adulterants was established based on the classic molecular authentication methods. DNA was extracted by alkaline lysis and the specific primers were amplified by two-steps PCR amplification method. The denatured and annealing temperature and cycle numbers were optimized. When 100 x SYBR Green I was added in the PCR product, strong green fluorescence was visualized under 365 nm UV whereas adulterants without. The whole process can complete in 30-45 minutes. The established method provides the technical support for authentication of the snakes on field.

Detection of organic residues on poultry processing equipment surfaces by LED-induced fluorescence imaging

Science.gov (United States)

Organic residues on equipment surfaces in poultry processing plants can generate cross- contamination and increase the risk of unsafe food for consumers. This research was aimed to investigate the potential of LED-induced fluorescence imaging technique for rapid inspection of stainless steel proces...

Production and testing of 244Cm-labeled fluorescent polystyrene latex microspheres

International Nuclear Information System (INIS)

Guilmette, R.A.; Mueller, H.L.; Brodbeck, R.D.

1988-01-01

To provide a useful tool for studying the mechanisms of retention and translocation of respirable-sized, alpha-emitting particles, we have developed a method of incorporating 244 Cm into fluorescent polystyrene latex microspheres. The resultant particles contain alpha radioactivity comparable to μm-size (AMAD) 239 Pu0 2 particles, but are easily visible by fluorescent light microscopy. Preliminary testing of the particles with dog macrophages in vitro has shown that the initial uptake of these Cm-labeled particles is more rapid than uptake of unlabeled particles of similar size. We are continuing to develop procedures for achieving better particle yields, smaller dispersity of particle size distributions and improved retention of the Cm label by the particles. (author)

Whose Maturity is it Anyway?

DEFF Research Database (Denmark)

Lasrado, Lester Allan; Vatrapu, Ravi; Mukkamala, Raghava Rao

2017-01-01

This paper presents results from an ongoing empirical study that seeks to understand the influence of different quantitative methods on the design and assessment of maturity models. Although there have been many academic publications on maturity models, there exists a significant lack of understa...

Maturity of the PWR

International Nuclear Information System (INIS)

Bacher, P.; Rapin, M.; Aboudarham, L.; Bitsch, D.

1983-03-01

Figures illustrating the predominant position of the PWR system are presented. The question is whether on the basis of these figures the PWR can be considered to have reached maturity. The following analysis, based on the French program experience, is an attempt to pinpoint those areas in which industrial maturity of the PWR has been attained, and in which areas a certain evolution can still be expected to take place

Intra-follicular interactions affecting mammalian oocyte maturation

NARCIS (Netherlands)

van Tol, H.T.A.|info:eu-repo/dai/nl/313871817

2009-01-01

Nuclear oocyte maturation is defined as reinitiation and progression of the first meiotic division and subsequently formation of the methaphase II (MII) plate. Concomitantly with nuclear maturation, cytoplasmic maturation which is essential for proper fertilization and early embryo development is

Growth indicators in orthodontic patients. Part 1: comparison of cervical vertebral maturation and hand-wrist skeletal maturation.

Science.gov (United States)

Litsas, G; Ari-Demirkaya, A

2010-12-01

The purpose of this study was to predict the skeletal maturation status based on the assessment of cervical vertebrae from lateral cephalometric radiographs and to compare these findings with the skeletal maturity of the same individuals judged from the hand-wrist radiographs. Lateral cephalometric and left hand-wrist radiographs of 393 Caucasian children from 8 to 18 years old were evaluated. On the hand-wrist radiographs the classification of Bjork [1972] and Grave and Brown [1976] was used to assess skeletal maturity (HWSS). Cervical vertebral maturation was also evaluated on lateral cephalometric radiographs using the improved CVMS method described by Baccetti, Franchi, and McNamara [2002]. These methods were correlated using the chi-square test. The chi-square test showed that skeletal maturational values obtained by the CVMS method were significantly correlated with the skeletal values obtained from the hand-wrist analysis for both genders (pmaturity.

Plasmonic photocatalyst-like fluorescent proteins for generating reactive oxygen species

Science.gov (United States)

Leem, Jung Woo; Kim, Seong-Ryul; Choi, Kwang-Ho; Kim, Young L.

2018-03-01

The recent advances in photocatalysis have opened a variety of new possibilities for energy and biomedical applications. In particular, plasmonic photocatalysis using hybridization of semiconductor materials and metal nanoparticles has recently facilitated the rapid progress in enhancing photocatalytic efficiency under visible or solar light. One critical underlying aspect of photocatalysis is that it generates and releases reactive oxygen species (ROS) as intermediate or final products upon light excitation or activation. Although plasmonic photocatalysis overcomes the limitation of UV irradiation, synthesized metal/semiconductor nanomaterial photocatalysts often bring up biohazardous and environmental issues. In this respect, this review article is centered in identifying natural photosensitizing organic materials that can generate similar types of ROS as those of plasmonic photocatalysis. In particular, we propose the idea of plasmonic photocatalyst-like fluorescent proteins for ROS generation under visible light irradiation. We recapitulate fluorescent proteins that have Type I and Type II photosensitization properties in a comparable manner to plasmonic photocatalysis. Plasmonic photocatalysis and protein photosensitization have not yet been compared systemically in terms of ROS photogeneration under visible light, although the phototoxicity and cytotoxicity of some fluorescent proteins are well recognized. A comprehensive understanding of plasmonic photocatalyst-like fluorescent proteins and their potential advantages will lead us to explore new environmental, biomedical, and defense applications.

Observing Fluorescent Probes in Living Cells using a Low-Cost LED Flashlight Retrofitted to a Common Vintage Light Microscope

Directory of Open Access Journals (Sweden)

G. A. Babbitt

2013-03-01

Full Text Available While the application of molecular biological techniques based upon fluorescent probes has rapidly expanded over recent decades, the equipment cost of fluorescent microscopy has largely prevented its adoption in the college and high school classroom. We offer a simple solution to this problem by describing in detail how to build with simple tools, a fluorescent microscope using a common brand of colored LED flashlights and second-hand components of vintage Nikon microscopes. This extremely low cost solution is qualitatively compared to an expensive modern Zeiss system.

Highly sensitive and selective fluorescent assay for guanine based on the Cu(2+)/eosin Y system.

Science.gov (United States)

Shi, Huimin; Cui, Yi; Gong, Yijun; Feng, Suling

2016-05-15

A fluorescent probe has been developed for the determination of guanine based on the quenched fluorescence signal of Cu(2+)/eosin Y. Cu(2+) interacted with eosin Y, resulting in fluorescence quenching. Subsequently, with the addition of guanine to the Cu(2+)/eosin Y system, guanine reacted with Cu(2+) to form 1:1 chelate cation, which further combined with eosin Y to form a 1:1 ternary ion-association complex by electrostatic attraction and hydrophobic interaction, resulting in significant decrease of the fluorescence. Hence, a fluorescent system was constructed for rapid, sensitive and selective detection of guanine with a detection limit as low as 1.5 nmol L(-1) and a linear range of 3.3-116 nmol L(-1). The method has been applied satisfactorily to the determination of guanine in DNA and urine samples with the recoveries from 98.7% to 105%. This study significantly expands the realm of application of ternary ion-association complex in fluorescence probe. Copyright © 2016 Elsevier B.V. All rights reserved.

Gender, mature appearance, alcohol use, and dating as correlates of sexual partner accumulation from ages 16-26 years.

Science.gov (United States)

Zimmer-Gembeck, Melanie J; Collins, W Andrew

2008-06-01

To determine growth in sexual partnering from age 16-26 years, and to test whether biological and social factors launched these growth patterns. A prospective design was used. Participants were 176 young people (47% female) followed from birth to age 26 years. Sexual partnering was measured as the accumulated number of different sexual intercourse partners at ages 16, 19, 23, and 26 years. Physical appearance of maturity, alcohol use, and dating were measured at ages 13-16 via observations, interviews, and questionnaires. Mature appearance at age 13 years, use of alcohol more than monthly at age 16, and a history of a steady romantic partner before age 16 were each associated with a greater number of sexual intercourse partners by age 16. However a more mature appearance, more frequent alcohol use, and greater dating involvement did not foreshadow a steeper accumulation of sexual partners between ages 16 and 26. Only gender had such a "growth" influence, with males accruing sexual partners more rapidly from the ages of 16-26 years when compared with females. Adolescents had accumulated a higher number of sexual partners by age 16 years when they looked older, drank alcohol more frequently, and were more involved with dating in early to middle adolescence. Also male gender was associated with accumulation of sexual partners more rapidly between ages 16 and 26 years, and there was little indication that the accumulation of different sexual partners had begun to slow by age 26 for the average participant.

Kinetic analysis of the mechanism and specificity of protein-disulfide isomerase using fluorescence-quenched peptides

DEFF Research Database (Denmark)

Westphal, V; Spetzler, J C; Meldal, M

1998-01-01

Protein-disulfide isomerase (PDI) is an abundant folding catalyst in the endoplasmic reticulum of eukaryotic cells. PDI introduces disulfide bonds into newly synthesized proteins and catalyzes disulfide bond isomerizations. We have synthesized a library of disulfide-linked fluorescence......-quenched peptides, individually linked to resin beads, for two purposes: 1) to probe PDI specificity, and 2) to identify simple, sensitive peptide substrates of PDI. Using this library, beads that became rapidly fluorescent by reduction by human PDI were selected. Amino acid sequencing of the bead-linked peptides...

Fluorescence spectroscopy as a tool for determination of organic matter removal efficiency at water treatment works

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M. Z. Bieroza

2010-04-01

Full Text Available Organic matter (OM in drinking water treatment is a common impediment responsible for increased coagulant and disinfectant dosages, formation of carcinogenic disinfection-by products, and microbial re-growth in distribution system. The inherent heterogeneity of OM implies the utilization of advanced analytical techniques for its characterization and assessment of removal efficiency. Here, the application of simple fluorescence excitation-emission technique to OM characterization in drinking water treatment is presented. The fluorescence data of raw and clarified water was obtained from 16 drinking water treatment works. The reduction in fulvic-like fluorescence was found to significantly correlate with OM removal measured with total organic carbon (TOC. Fluorescence properties, fulvic- and tryptophan-like regions, were found to discriminate OM fractions of different removal efficiencies. The results obtained in the study show that fluorescence spectroscopy provides a rapid and accurate characterization and quantification of OM fractions and indication of their treatability in conventional water treatment.

Maturity acceleration of Italian dried sausage by Staphylococcus carnosus - Relationship between maturity and flavor compounds

DEFF Research Database (Denmark)

Stahnke, Louise Heller; Holck, A.; Jensen, Anni

2002-01-01

. Sausages with S. carnosus 833 matured more than 2 wk faster than control sausages. Maturity correlated significantly with higher amounts of branched-chain aldehydes and alcohols and both branched- and straight-chain methyl ketones-compounds arising from the breakdown of the amino acids leucine, isoleucine...

A PACS maturity model: a systematic meta-analytic review on maturation and evolvability of PACS in the hospital enterprise.

NARCIS (Netherlands)

Wetering, R. van de; Batenburg, R.

2009-01-01

INTRODUCTION: With PACS and medical imaging technology maturing, the importance of organizational maturity and effective deployment of PACS in the hospital enterprise are becoming significant. OBJECTIVE: The objective of this paper is twofold. Firstly, PACS literature on maturity and evolvability in

Statistical filtering in fluorescence microscopy and fluorescence correlation spectroscopy

Czech Academy of Sciences Publication Activity Database

Macháň, Radek; Kapusta, Peter; Hof, Martin

Roč. 406 , č. 20 (2014), s. 4797-4813 ISSN 1618-2642 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388955 Keywords : Filtered fluorescence correlation spectroscopy * Fluorescence lifetime correlation spectroscopy * Fluorescence spectral correlation spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.436, year: 2014

PROJECT MANAGEMENT MATURITY: AN ASSESSMENT OF MATURITY FOR DEVELOPING PILOT PLANTS

Directory of Open Access Journals (Sweden)

H.K. Mittermaier

2012-01-01

Full Text Available

ENGLISH ABSTRACT: Despite the current economic climate, the South African mining and engineering industry is experiencing a very promising future, with a large number of capital projects in the offing. It is inevitable that pilot plant development will form part of this future as a risk mitigation technique. This study found that, even though the terms ‘pilot plant’ and ‘project management maturity’ are familiar within the industry, no link between these two could be found in the literature. A number of maturity models exist; and one developed by PMSolutions was selected to perform an assessment of the current level of project management maturity within the South African mining and engineering industry pertaining to the development of pilot plants. The Delphi technique was used to determine the views of experts in the South African mining, mineral processing, petrochemical, nuclear, and mechanical sectors regarding this maturity. A significant difference was observed between the current level of maturity and the required level of maturity in all but one of the nine knowledge areas defined by the Project Management Institute. The two knowledge areas of project time and risk management showed significant differences between current and required maturity levels, and were identified as key areas for improvement.

AFRIKAANSE OPSOMMING: Ten spyte van die huidige ekonomiese klimaat ondervind die Suid-Afrikaanse mynbou- en ingenieursbedryf ’n baie bemoedigende toekoms, met ’n groot aantal kapitaalprojekte in die vooruitsig. Ten einde risiko’s te verlaag, sal die ontwikkeling van loodsaanlegte noodwendig deel van hierdie toekoms uitmaak. Daar is gevind dat, alhoewel die terme ‘loodsaanleg’ en ‘projekbestuur volwassenheid’ in die nywerheid bekend is, geen skakeling van hierdie twee terme in die literatuur opgespoor kon word nie. ’n Aantal volwassenheid modelle bestaan; en een wat deur PMSolutions ontwikkel is, is gekies om

Maturation of the human fetal startle response: evidence for sex-specific maturation of the human fetus.

Science.gov (United States)

Buss, Claudia; Davis, Elysia Poggi; Class, Quetzal A; Gierczak, Matt; Pattillo, Carol; Glynn, Laura M; Sandman, Curt A

2009-10-01

Despite the evidence for early fetal experience exerting programming influences on later neurological development and health risk, very few prospective studies of human fetal behavior have been reported. In a prospective longitudinal study, fetal nervous system maturation was serially assessed by monitoring fetal heart rate (FHR) responses to vibroacoustic stimulation (VAS) in 191 maternal/fetal dyads. Responses were not detected at 26 weeks gestational age (GA). Sex-specific, age-characteristic changes in the FHR response to VAS were observed by 31 weeks' GA. Males showed larger responses and continued to exhibit maturational changes until 37 weeks' GA, females however, presented with a mature FHR startle response by 31 weeks' GA. The results indicate that there are different rates of maturation in the male and female fetuses that may have implications for sex-specific programming influences.

A low cytotoxic and ratiometric fluorescent nanosensor based on carbon-dots for intracellular pH sensing and mapping

International Nuclear Information System (INIS)

Du Fangkai; Ming Yunhao; Zeng Fang; Yu Changmin; Wu Shuizhu

2013-01-01

Intracellular pH plays a critical role in the function of cells, and its regulation is essential for most cellular processes. In this study, we demonstrate a fluorescence resonance energy transfer (FRET)-based ratiometric pH nanosensor with carbon-dot (CD) as the carrier. The sensor was prepared by covalently linking a pH-sensitive fluorescent dye (fluorescein isothiocyanate, FITC) onto carbon-dot. As the FRET donor, the carbon-dot exhibits bright fluorescence emission as well as λ ex -dependent photoluminescence emission, and a suitable excitation wavelength for the donor (CD) can be chosen to match the energy acceptor (fluorescein moiety). The fluorescein moieties on a CD undergo structural and spectral conversion as the pH changes, affording the nanoplatform a FRET-based pH sensor. The CD-based system exhibits a significant change in fluorescence intensity ratio between pH 4 and 8 with a pK a value of 5.69. It also displays excellent water dispersibility, good spectral reversibility, satisfactory cell permeability and low cytotoxicity. Following the living cell uptake, this nanoplatform with dual-chromatic emissions can facilitate real-time visualization of the pH evolution involved in the endocytic pathway of the nanosensor. This reversible and low cytotoxic fluorescent nanoplatform may be highly valuable in a variety of biological studies, such as endocytic trafficking, endosome/lysosome maturation, and pH regulation in subcellular organelles. (paper)

Assessment of skeletal maturation using mandibular second molar maturation stages.

Science.gov (United States)

Goyal, S; Goyal, S; Gugnani, N

2014-01-01

To investigate the relationship between cervical vertebrae maturation and mandibular second molar calcification stages. The study was designed as a retrospective, descriptive and crosssectional research project. Pre-treatment lateral cephalograms and panoramic radiographs of 99 males and 110 females in the age range of 7 to 18 years 7 months were evaluated with Demirjian Index (DI) and cervical vertebrae maturation indicators (CVMI) of Hassel and Farman. A null hypothesis was proposed that there is no relation between CVMI and DI. A highly significant association (Pearson's contingency coefficient 0.713 for males and 0.863 for females) was found between DI and CVMI. In males, the DI stage E corresponded to stage 2 of CVMI (pre-peak of pubertal growth spurt) and DI stages F and G corresponded to stages 3 and 4 of CVMI (peak of pubertal growth spurt). DI stage H was associated with stages 5 and 6 of CVMI (end of pubertal growth spurt). In females, the DI stages C, D corresponded to CVMI stages 1, 2; DI stages E, F with CVMI stages 3, 4; DI stages G, H with CVMI stages 5, 6. Mandibular second molar calcification stages can be used as indicators for assessment of skeletal maturity.

Raft-based sphingomyelin interactions revealed by new fluorescent sphingomyelin analogs

Science.gov (United States)

Kinoshita, Masanao; Suzuki, Kenichi G.N.; Takada, Misa; Ano, Hikaru; Abe, Mitsuhiro; Makino, Asami; Kobayashi, Toshihide; Hirosawa, Koichiro M.; Fujiwara, Takahiro K.; Murata, Michio

2017-01-01

Sphingomyelin (SM) has been proposed to form cholesterol-dependent raft domains and sphingolipid domains in the plasma membrane (PM). How SM contributes to the formation and function of these domains remains unknown, primarily because of the scarcity of suitable fluorescent SM analogs. We developed new fluorescent SM analogs by conjugating a hydrophilic fluorophore to the SM choline headgroup without eliminating its positive charge, via a hydrophilic nonaethylene glycol linker. The new analogs behaved similarly to the native SM in terms of their partitioning behaviors in artificial liquid order-disorder phase-separated membranes and detergent-resistant PM preparations. Single fluorescent molecule tracking in the live-cell PM revealed that they indirectly interact with each other in cholesterol- and sphingosine backbone–dependent manners, and that, for ∼10–50 ms, they undergo transient colocalization-codiffusion with a glycosylphosphatidylinositol (GPI)-anchored protein, CD59 (in monomers, transient-dimer rafts, and clusters), in CD59-oligomer size–, cholesterol-, and GPI anchoring–dependent manners. These results suggest that SM continually and rapidly exchanges between CD59-associated raft domains and the bulk PM. PMID:28330937

A Set Theoretical Approach to Maturity Models

DEFF Research Database (Denmark)

Lasrado, Lester; Vatrapu, Ravi; Andersen, Kim Normann

2016-01-01

characterized by equifinality, multiple conjunctural causation, and case diversity. We prescribe methodological guidelines consisting of a six-step procedure to systematically apply set theoretic methods to conceptualize, develop, and empirically derive maturity models and provide a demonstration......Maturity Model research in IS has been criticized for the lack of theoretical grounding, methodological rigor, empirical validations, and ignorance of multiple and non-linear paths to maturity. To address these criticisms, this paper proposes a novel set-theoretical approach to maturity models...

Enhancement of uranyl fluorescence using trimesic acid: Ligand sensitization and co-fluorescence

Energy Technology Data Exchange (ETDEWEB)

Maji, S. [Chemistry Group, Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Viswanathan, K.S., E-mail: vish@igcar.gov.in [Chemistry Group, Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2011-09-15

Trimesic acid (TMA) was shown to sensitize and enhance uranyl fluorescence in aqueous medium, with the enhancement being a maximum at pH 5.0. Fluorescence spectra and lifetime data together suggest that TMA complexes with uranyl (UO{sub 2}{sup 2+}). The fluorescence of UO{sub 2}{sup 2+} in its acid complex is further enhanced by more than two orders of magnitude following the addition of Y{sup 3+}; a process referred to as co-fluorescence, leading to the possibility of detecting uranium at sub ng/mL level. The present study demonstrates, for the first time, fluorescence enhancement of the uranyl species due to co-fluorescence. - Highlights: > Trimesic acid was shown to sensitize and enhance the fluorescence of uranium in aqueous medium. > This ligand also exhibited co-fluorescence of uranium with Y{sup 3+}. > To the best of our knowledge this is the first report of co-fluorescence in uranium. > The enhancement of uranium fluorescence, resulted in detection limits in the ng/mL regime.

A combination of positive dielectrophoresis driven on-line enrichment and aptamer-fluorescent silica nanoparticle label for rapid and sensitive detection of Staphylococcus aureus.

Science.gov (United States)

Shangguan, Jingfang; Li, Yuhong; He, Dinggeng; He, Xiaoxiao; Wang, Kemin; Zou, Zhen; Shi, Hui

2015-07-07

Staphylococcus aureus (S. aureus) is an important human pathogen that causes several diseases ranging from superficial skin infections to life-threatening diseases. Here, a method combining positive dielectrophoresis (pDEP) driven on-line enrichment and aptamer-fluorescent silica nanoparticle label has been developed for the rapid and sensitive detection of S. aureus in microfluidic channels. An aptamer, having high affinity to S. aureus, is used as the molecular recognition tool and immobilized onto chloropropyl functionalized fluorescent silica nanoparticles through a click chemistry approach to obtain S. aureus aptamer-nanoparticle bioconjugates (Apt(S.aureus)/FNPs). The pDEP driven on-line enrichment technology was used for accumulating the Apt(S.aureus)/FNP labeled S. aureus. After incubating with S. aureus, the mixture of Apt(S.aureus)/FNP labeled S. aureus and Apt(S.aureus)/FNPs was directly introduced into the pDEP-based microfluidic system. By applying an AC voltage in a pDEP frequency region, the Apt(S.aureus)/FNP labelled S. aureus moved to the electrodes and accumulated in the electrode gap, while the free Apt(S.aureus)/FNPs flowed away. The signal that came from the Apt(S.aureus)/FNP labelled S. aureus in the focused detection areas was then detected. Profiting from the specificity of aptamer, signal amplification of FNP label and pDEP on-line enrichment, this assay can detect as low as 93 and 270 cfu mL(-1)S. aureus in deionized water and spiked water samples, respectively, with higher sensitivities than our previously reported Apt(S.aureus)/FNP based flow cytometry. Moreover, without the need for separation and washing steps usually required for FNP label involved bioassays, the total assay time including sample pretreatment was within 2 h.

Quantitative analysis of essential oils of Thymus daenensis using laser-induced fluorescence and Raman spectroscopy.

Science.gov (United States)

Khoshroo, H; Khadem, H; Bahreini, M; Tavassoli, S H; Hadian, J

2015-11-10

Laser-induced fluorescence and Raman spectroscopy are used for the investigation of different genotypes of Thymus daenensis native to the Ilam province of Iran. Different genotypes of T. daenensis essential oils, labeled T1 through T7, possess slight differences with regard to the composition of the thymol. The gas chromatography-mass spectrometry (GC-MS) method is performed to determine the concentration of each constituent as a reference method. The Raman spectra of different concentrations of pure thymol dissolved in hexane as standard samples are obtained via a laboratory prototype Raman spectroscopy setup for the calculation of the calibration curve. The regression coefficient and limit of detection are calculated. The possibility of the differentiation of different genotypes of T. daenensis is also examined by laser-induced fluorescence spectroscopy, although we do not know the exact amounts of their components. All the fluorescence spectral information is used jointly by cluster analysis to differentiate between 7 genotypes. Our results demonstrate the acceptable precision of Raman spectroscopy with GC-MS and corroborate the capacity of Raman spectroscopy in applications in the quantitative analysis field. Furthermore, the cluster analysis results show that laser-induced fluorescence spectroscopy is an acceptable technique for the rapid classification of different genotypes of T. daenensis without having any previous information of their exact amount of constituents. So, the ability to rapidly and nondestructively differentiate between genotypes makes it possible to efficiently select high-quality herbs from many samples.

In vivo multiphoton tomography and fluorescence lifetime imaging of human brain tumor tissue.

Science.gov (United States)

Kantelhardt, Sven R; Kalasauskas, Darius; König, Karsten; Kim, Ella; Weinigel, Martin; Uchugonova, Aisada; Giese, Alf

2016-05-01

High resolution multiphoton tomography and fluorescence lifetime imaging differentiates glioma from adjacent brain in native tissue samples ex vivo. Presently, multiphoton tomography is applied in clinical dermatology and experimentally. We here present the first application of multiphoton and fluorescence lifetime imaging for in vivo imaging on humans during a neurosurgical procedure. We used a MPTflex™ Multiphoton Laser Tomograph (JenLab, Germany). We examined cultured glioma cells in an orthotopic mouse tumor model and native human tissue samples. Finally the multiphoton tomograph was applied to provide optical biopsies during resection of a clinical case of glioblastoma. All tissues imaged by multiphoton tomography were sampled and processed for conventional histopathology. The multiphoton tomograph allowed fluorescence intensity- and fluorescence lifetime imaging with submicron spatial resolution and 200 picosecond temporal resolution. Morphological fluorescence intensity imaging and fluorescence lifetime imaging of tumor-bearing mouse brains and native human tissue samples clearly differentiated tumor and adjacent brain tissue. Intraoperative imaging was found to be technically feasible. Intraoperative image quality was comparable to ex vivo examinations. To our knowledge we here present the first intraoperative application of high resolution multiphoton tomography and fluorescence lifetime imaging of human brain tumors in situ. It allowed in vivo identification and determination of cell density of tumor tissue on a cellular and subcellular level within seconds. The technology shows the potential of rapid intraoperative identification of native glioma tissue without need for tissue processing or staining.

Decomposition characteristics of humic-like matters with the hollow ellipsoid structure sludge inoculated from decayed soil in mature landfill leachate.

Science.gov (United States)

Zhang, Jie; Lan, Sijie; Niu, Dongjie; Zhao, Youcai

2016-01-01

The organics in mature leachate are mainly humic-like matters, which account for over 80% weight of the total organics. In this work, the microorganisms in decayed soil were found to be capable of decomposing the humic-like matters evidently using an anaerobic-aerobic/anoxic bioprocess in two sequencing bio-reactors. The 3D excitation-emission matrix and Fourier transform infrared (FT-IR) were applied to characterize the variation of dissolved organic matters in mature leachate while sludge morphology was characterized by scanning electron microscopy. The intensities of fluorescence peaks A and C of leachate effluents were 71.66% and 48.75% lower than those of influents, respectively, which indicated the extraordinary degradation ability of microorganisms inoculated from the decayed soil. Meanwhile a kind of distinctive hollow ellipsoid structure sludge organized by tiny soil particles was observed, which might favour the humic-like matters' decomposition and has never been reported before as we know. The formation mechanisms of hollow ellipsoid structure sludge will need further study.

Rapid quantification of live/dead lactic acid bacteria in probiotic products using high-sensitivity flow cytometry

Science.gov (United States)

He, Shengbin; Hong, Xinyi; Huang, Tianxun; Zhang, Wenqiang; Zhou, Yingxing; Wu, Lina; Yan, Xiaomei

2017-06-01

A laboratory-built high-sensitivity flow cytometer (HSFCM) was employed for the rapid and accurate detection of lactic acid bacteria (LAB) and their viability in probiotic products. LAB were stained with both the cell membrane-permeable SYTO 9 green-fluorescent nucleic acid stain and the red-fluorescent nucleic acid stain, propidium iodide, which penetrates only bacteria with compromised membranes. The side scatter and dual-color fluorescence signals of single bacteria were detected simultaneously by the HSFCM. Ultra-high temperature processing milk and skim milk spiked with Lactobacillus casei were used as the model systems for the optimization of sample pretreatment and staining. The viable LAB counts measured by the HSFCM were in good agreement with those of the plate count method, and the measured ratios between the live and dead LAB matched well with the theoretical ratios. The established method was successfully applied to the rapid quantification of live/dead LAB in yogurts and fermented milk beverages of different brands. Moreover, the concentration and viability status of LAB in ambient yogurt, a relatively new yet popular milk product in China, are also reported.

The effect of Propionibacterium acnes on maturation of dendritic cells derived from acne patients' peripherial blood mononuclear cells.

Directory of Open Access Journals (Sweden)

Maria Juszkiewicz-Borowiec

2009-01-01

Full Text Available Propionibacterium acnes (P. acnes has been implicated in the pathogenesis of acne vulgaris which is the most common cutaneous disorder. It has a proinflammatory activity and takes part in immune reactions modulating the Th1/Th2 cellular response. The exposure of dendritic cells (DCs to whole bacteria, their components, cytokines or other inflammatory stimuli and infectious agents induces differentiation from immature DCs into antigen-presenting mature DCs. The aim of the study was to evaluate the capability of P. acnes to induce the maturation of DCs. We stimulated monocyte derived dendritic cells (Mo-DCs from acne patients with various concetrations of heat-killed P. acnes (10(6-10(8 bacteria/ml cultured from acne lesions. The results showed an increase in CD80+/CD86+/DR+ and CD83+/CD1a+/DR+ cells percentage depending on the concetration of P. acnes. The expression of CD83 and CD80 (shown as the mean fluorescence intensity - MFI increased with higher concetrations of P. acnes. There were also significant correlations between MFI of CD83, CD80, CD86 and concetration of P. acnes. The study showed that P. acnes in the concetration of 10(8 bacteria/ml is most effective in the induction of Mo-DCs maturation. Futher studies concerning the influence on the function of T cells are needed.

Fast and accurate automated cell boundary determination for fluorescence microscopy

Science.gov (United States)

Arce, Stephen Hugo; Wu, Pei-Hsun; Tseng, Yiider

2013-07-01

Detailed measurement of cell phenotype information from digital fluorescence images has the potential to greatly advance biomedicine in various disciplines such as patient diagnostics or drug screening. Yet, the complexity of cell conformations presents a major barrier preventing effective determination of cell boundaries, and introduces measurement error that propagates throughout subsequent assessment of cellular parameters and statistical analysis. State-of-the-art image segmentation techniques that require user-interaction, prolonged computation time and specialized training cannot adequately provide the support for high content platforms, which often sacrifice resolution to foster the speedy collection of massive amounts of cellular data. This work introduces a strategy that allows us to rapidly obtain accurate cell boundaries from digital fluorescent images in an automated format. Hence, this new method has broad applicability to promote biotechnology.

Infrared spectroscopy reveals both qualitative and quantitative differences in equine subchondral bone during maturation

Science.gov (United States)

Kobrina, Yevgeniya; Isaksson, Hanna; Sinisaari, Miikka; Rieppo, Lassi; Brama, Pieter A.; van Weeren, René; Helminen, Heikki J.; Jurvelin, Jukka S.; Saarakkala, Simo

2010-11-01

The collagen phase in bone is known to undergo major changes during growth and maturation. The objective of this study is to clarify whether Fourier transform infrared (FTIR) microspectroscopy, coupled with cluster analysis, can detect quantitative and qualitative changes in the collagen matrix of subchondral bone in horses during maturation and growth. Equine subchondral bone samples (n = 29) from the proximal joint surface of the first phalanx are prepared from two sites subjected to different loading conditions. Three age groups are studied: newborn (0 days old), immature (5 to 11 months old), and adult (6 to 10 years old) horses. Spatial collagen content and collagen cross-link ratio are quantified from the spectra. Additionally, normalized second derivative spectra of samples are clustered using the k-means clustering algorithm. In quantitative analysis, collagen content in the subchondral bone increases rapidly between the newborn and immature horses. The collagen cross-link ratio increases significantly with age. In qualitative analysis, clustering is able to separate newborn and adult samples into two different groups. The immature samples display some nonhomogeneity. In conclusion, this is the first study showing that FTIR spectral imaging combined with clustering techniques can detect quantitative and qualitative changes in the collagen matrix of subchondral bone during growth and maturation.

Design of mitochondria-targeted colorimetric and ratiometric fluorescent probes for rapid detection of SO2 derivatives in living cells

Science.gov (United States)

Yang, Yutao; Zhou, Tingting; Bai, Bozan; Yin, Caixia; Xu, Wenzhi; Li, Wei

2018-05-01

Two mitochondria-targeted colorimetric and ratiometric fluorescent probes for SO2 derivatives were constructed based on the SO2 derivatives-triggered Michael addition reaction. The probes exhibit high specificity toward HSO3-/SO32- by interrupting their conjugation system resulting in a large ratiometric blue shift of 46-121 nm in their emission spectrum. The two well-resolved emission bands can ensure accurate detection of HSO3-. The detection limits were calculated to be 1.09 and 1.35 μM. Importantly, probe 1 and probe 2 were successfully used to fluorescence ratiometric imaging of endogenous HSO3- in BT-474 cells.

Mature students' perspectives of studying radiography

International Nuclear Information System (INIS)

Williams, M.; Decker, S.

2009-01-01

The study set out to explore the experiences of all final year mature students on a diagnostic radiography course, in one United Kingdom University. The aims were to identify any difficulties they may have had and to make recommendations to improve mature students' learning experiences with the hope of lowering attrition rates in this group. A qualitative study involving one-to-one audio recorded interviews was utilised. Analysis of the transcripts of interviews suggested that the group believed that their maturity and previous experiences helped them in the clinical environment and put them in a good position, when asked, to counsel younger students. However for some of the mature students these experiential skills did not extend fully into seeking appropriate support for themselves. The mature students were found to be highly motivated but there was a conflict between balancing clinical and academic aspects of studying as well as balancing studying with home life. The group was found to be unprepared for the volume of academic work and its detrimental effect on family life as they sacrificed other aspects of their lives in order to complete the course. It is recommended that forewarning and forearming prospective mature students be considered by radiography education providers. Setting up and utilising an on-line forum providing a 24/7 peer support environment would aid in coping with academic, clinical or personal problems

Rapid differentiation of Francisella species and subspecies by fluorescent in situ hybridization targeting the 23S rRNA

Directory of Open Access Journals (Sweden)

Trebesius Karlheinz

2010-03-01

Full Text Available Abstract Background Francisella (F. tularensis is the causative agent of tularemia. Due to its low infectious dose, ease of dissemination and high case fatality rate, F. tularensis was the subject in diverse biological weapons programs and is among the top six agents with high potential if misused in bioterrorism. Microbiological diagnosis is cumbersome and time-consuming. Methods for the direct detection of the pathogen (immunofluorescence, PCR have been developed but are restricted to reference laboratories. Results The complete 23S rRNA genes of representative strains of F. philomiragia and all subspecies of F. tularensis were sequenced. Single nucleotide polymorphisms on species and subspecies level were confirmed by partial amplification and sequencing of 24 additional strains. Fluorescent In Situ Hybridization (FISH assays were established using species- and subspecies-specific probes. Different FISH protocols allowed the positive identification of all 4 F. philomiragia strains, and more than 40 F. tularensis strains tested. By combination of different probes, it was possible to differentiate the F. tularensis subspecies holarctica, tularensis, mediasiatica and novicida. No cross reactivity with strains of 71 clinically relevant bacterial species was observed. FISH was also successfully applied to detect different F. tularensis strains in infected cells or tissue samples. In blood culture systems spiked with F. tularensis, bacterial cells of different subspecies could be separated within single samples. Conclusion We could show that FISH targeting the 23S rRNA gene is a rapid and versatile method for the identification and differentiation of F. tularensis isolates from both laboratory cultures and clinical samples.

Biomolecule-to-fluorescent-color encoder: modulation of fluorescence emission via DNA structural changes

Science.gov (United States)

Nishimura, Takahiro; Ogura, Yusuke; Yamada, Kenji; Ohno, Yuko; Tanida, Jun

2014-01-01

A biomolecule-to-fluorescent-color (B/F) encoder for optical readout of biomolecular information is proposed. In the B/F encoder, a set of fluorescence wavelengths and their intensity levels are used for coding of a biomolecular signal. A hybridization chain reaction of hairpin DNAs labeled with fluorescent reporters was performed to generate the fluorescence color codes. The fluorescence is modulated via fluorescence resonance energy transfer, which is controlled by DNA structural changes. The results demonstrate that fluorescent color codes can be configured based on two wavelengths and five intensities using the B/F encoder, and the assigned codes can be retrieved via fluorescence measurements. PMID:25071950

Europium Uptake and Partitioning in Oat (Avena sativa) Roots as studied By Laser-Induced Fluorescence Spectroscopy and Confocal Microscopy Profiling Technique

International Nuclear Information System (INIS)

Fellows, Robert J.; Wang, Zheming; Ainsworth, Calvin C.

2003-01-01

The uptake of Eu3+ by elongating oat plant roots was studied by fluorescence spectroscopy, fluorescence lifetime measurement, as well as laser excitation time-resolved confocal fluorescence profiling technique. The results of this work indicated that the initial uptake of Eu(III) by oat root was most evident within the apical meristem of the root just proximal to the root cap. Distribution of assimilated Eu(III) within the roots differentiation and elongation zone was non-uniform. Higher concentrations were observed within the vascular cylinder, specifically in the phloem and developing xylem parenchyma. Elevated levels of the metal were also observed in the root hairs of the mature root. The concentration of assimilated Eu3+ dropped sharply from the apical meristem to the differentiation and elongation zone and then gradually decreased as the distance from the root cap increased. Fluorescence spectroscopic characteristics of the assimilated Eu3+ suggested that the Eu3+ exists a s inner-sphere mononuclear complexes inside the root. This work has also demonstrated the effectiveness of a time-resolved Eu3+ fluorescence spectroscopy and confocal fluorescence profiling techniques for the in vivo, real-time study of metal[Eu3+] accumulation by a functioning intact plant root. This approach can prove valuable for basic and applied studies in plant nutrition and environmental uptake of actinide radionuclides

A simple, rapid method to isolate salt glands for three-dimensional visualization, fluorescence imaging and cytological studies

Directory of Open Access Journals (Sweden)

Lim Tit-Meng

2010-10-01

Full Text Available Abstract Background Some plants inhabiting saline environment remove salts via the salt glands embedded in the epidermal tissues. Cytological studies of salt glands will provide valuable information to our understanding of the secretory process. Previous studies on salt gland histology relied mainly on two-dimensional microscopic observations of microtome sections. Optical sectioning properties of confocal laser scanning microscope offer alternative approach for obtaining three-dimensional structural information of salt glands. Difficulty in light penetration through intact leaves and interference from neighbouring leaf cells, however, impede the acquiring of good optical salt gland sections and limit its applications in salt gland imaging. Freeing the glands from adjacent leaf tissues will allow better manipulations for three-dimensional imaging through confocal laser scanning microscopy. Results Here, we present a simple and fast method for the isolation of individual salt glands released from the interference of neighbouring cells. About 100-200 salt glands could be isolated from just one cm2 of Avicennia officinalis leaf within hours and microscopic visualization of isolated salt glands was made possible within a day. Using these isolated glands, confocal laser scanning microscopic techniques could be applied and better resolution salt gland images could be achieved. By making use of their intrinsic fluorescent properties, optical sections of the gland cells could be acquired without the use of fluorescent probes and the corresponding three-dimensional images constructed. Useful cytological information of the salt gland cells could also be obtained through the applications of fluorescent dyes (e.g., LysoTracker® Red, FM®4-64, Texas Red®. Conclusions The study of salt glands directly at the glandular level are made possible with the successful isolation of these specialized structures. Preparation of materials for subsequent microscopic

Single-cell Raman and fluorescence microscopy reveal the association of lipid bodies with phagosomes in leukocytes

Science.gov (United States)

van Manen, Henk-Jan; Kraan, Yvonne M.; Roos, Dirk; Otto, Cees

2005-01-01

Cellular imaging techniques based on vibrational spectroscopy have become powerful tools in cell biology because the molecular composition of subcellular compartments can be visualized without the need for labeling. Using high-resolution, nonresonant confocal Raman microscopy on individual cells, we demonstrate here that lipid bodies (LBs) rich in arachidonate as revealed by their Raman spectra associate with latex bead-containing phagosomes in neutrophilic granulocytes. This finding was corroborated in macrophages and in PLB-985 cells, which can be induced to differentiate into neutrophil-like cells, by selective staining of LBs and visualization by confocal fluorescence microscopy. We further show that the accumulation of LBs near phagosomes is mediated at least in part by the flavohemoprotein gp91phox (in which “phox” is phagocyte oxidase), because different LB distributions around phagocytosed latex beads were observed in WT and gp91phox-deficient PLB-985 cells. gp91phox, which accumulates in the phagosomal membrane, is the catalytic subunit of the leukocyte NADPH oxidase, a critical enzyme in the innate immune response. Finally, time-lapse fluorescence microscopy experiments on neutrophils revealed that the LB-phagosome association is transient, similar to the “kiss-and-run” behavior displayed by endosomes involved in phagosome maturation. Because arachidonic acid (AA) has been shown to be involved in NADPH oxidase activation and phagosome maturation in neutrophils and macrophages, respectively, the findings reported here suggest that LBs may provide a reservoir of AA for local activation of these essential leukocyte functions. PMID:16002471

CDOM fluorescence as a proxy of DOC concentration in natural waters : a comparison of four contrasting tropical systems

OpenAIRE

Rochelle Newall, Emma; Hulot, F. D.; Janeau, Jean-Louis; Merroune, A.

2014-01-01

Chromophoric dissolved organic matter (CDOM) fluorescence or absorption is often proposed as a rapid alternative to chemical methods for the estimation of bulk dissolved organic carbon (DOC) concentration in natural waters. However, the robustness of this method across a wide range of systems remains to be shown. We measured CDOM fluorescence and DOC concentration in four tropical freshwater and coastal environments (estuary and coastal, tropical shallow lakes, water from the freshwater lens ...

Fluorescence in situ hybridization for phytoplasma and endophytic bacteria localization in plant tissues.

Science.gov (United States)

Bulgari, Daniela; Casati, Paola; Faoro, Franco

2011-11-01

In the present study, we developed a rapid and efficient fluorescence in situ hybridization assay (FISH) in non-embedded tissues of the model plant Catharanthus roseus for co-localizing phytoplasmas and endophytic bacteria, opening new perspectives for studying the interaction between these microorganisms. Copyright © 2011 Elsevier B.V. All rights reserved.

Maturation and upregulation of functions of murine dendritic cells (DCs) under the influence of purified aromatic-turmerone (AR).

Science.gov (United States)

Yonggang, Tan; Yiming, Meng; Heying, Zhang; Cheng, Sun; Qiushi, Wang; Xianghong, Yang; Wei, Zheng; Huawei, Zhou; Shan, Fengping

2012-10-01

The aim of this work is to evaluate the effects of purified aromatic-turmerone (ar-turmerione, AR) on murine dendritic cells (DCs). These impacts of AR on DCs from bone marrow derived DCs(BMDCs) were assessed with use of conventional scanning electron microscopy (SEM), fluorescence activated cell sorting (FACS), transmission electron microscopy (TEM), cytochemistry assay, FITC-dextran, bio-assay and enzyme linked immunosorbent assay (ELISA). We found that AR induced phenotypic maturation as evidenced by increased expression of CD86, CD40, CD83, CD80 and major histocompatibility complex II (MHC II). The functional tests showed the activity of acidic phosphatase (ACP) inside the DCs were downregulated after treatment with AR (which occurs when phagocytosis of DCs were decreased). Finally, we proved that AR increased the production of IL-12 and tumor necrosis factor α (TNF-α). These data suggested that AR could promote phenotypic and functional maturation of DCs and this adjuvant-like activity may have potential therapeutic value. It is therefore concluded that AR could exert positive modulation on murine DCs.

Rapid Cellular Phenotyping of Human Pluripotent Stem Cell-Derived Cardiomyocytes using a Genetically Encoded Fluorescent Voltage Sensor

Directory of Open Access Journals (Sweden)

Jordan S. Leyton-Mange

2014-02-01

Full Text Available In addition to their promise in regenerative medicine, pluripotent stem cells have proved to be faithful models of many human diseases. In particular, patient-specific stem cell-derived cardiomyocytes recapitulate key features of several life-threatening cardiac arrhythmia syndromes. For both modeling and regenerative approaches, phenotyping of stem cell-derived tissues is critical. Cellular phenotyping has largely relied upon expression of lineage markers rather than physiologic attributes. This is especially true for cardiomyocytes, in part because electrophysiological recordings are labor intensive. Likewise, most optical voltage indicators suffer from phototoxicity, which damages cells and degrades signal quality. Here we present the use of a genetically encoded fluorescent voltage indicator, ArcLight, which we demonstrate can faithfully report transmembrane potentials in human stem cell-derived cardiomyocytes. We demonstrate the application of this fluorescent sensor in high-throughput, serial phenotyping of differentiating cardiomyocyte populations and in screening for drug-induced cardiotoxicity.

Exploiting fluorescence for multiplex immunoassays on protein microarrays

International Nuclear Information System (INIS)

Herbáth, Melinda; Balogh, Andrea; Matkó, János; Papp, Krisztián; Prechl, József

2014-01-01

Protein microarray technology is becoming the method of choice for identifying protein interaction partners, detecting specific proteins, carbohydrates and lipids, or for characterizing protein interactions and serum antibodies in a massively parallel manner. Availability of the well-established instrumentation of DNA arrays and development of new fluorescent detection instruments promoted the spread of this technique. Fluorescent detection has the advantage of high sensitivity, specificity, simplicity and wide dynamic range required by most measurements. Fluorescence through specifically designed probes and an increasing variety of detection modes offers an excellent tool for such microarray platforms. Measuring for example the level of antibodies, their isotypes and/or antigen specificity simultaneously can offer more complex and comprehensive information about the investigated biological phenomenon, especially if we take into consideration that hundreds of samples can be measured in a single assay. Not only body fluids, but also cell lysates, extracted cellular components, and intact living cells can be analyzed on protein arrays for monitoring functional responses to printed samples on the surface. As a rapidly evolving area, protein microarray technology offers a great bulk of information and new depth of knowledge. These are the features that endow protein arrays with wide applicability and robust sample analyzing capability. On the whole, protein arrays are emerging new tools not just in proteomics, but glycomics, lipidomics, and are also important for immunological research. In this review we attempt to summarize the technical aspects of planar fluorescent microarray technology along with the description of its main immunological applications. (topical review)

Biological denitrification from mature landfill leachate using a food-waste-derived carbon source.

Science.gov (United States)

Yan, Feng; Jiang, Jianguo; Zhang, Haowei; Liu, Nuo; Zou, Quan

2018-05-15

The mature landfill leachate containing high ammonia concentration (>1000 mg/L) is a serious threat to environment; however, the low COD to TN ratio (C/N, waste and oil-added food waste, were first applied as external carbon sources for the biological nitrogen removal from mature landfill leachate in an aerobic/anoxic membrane bioreactor. "Acidogenic liquid b" served quite better than commercial sodium acetate, considering the higher denitrification efficiency and the slightly rapider denitrification rate. The effect of C/N and temperature were investigated under hydraulic retention time (HRT) of 7 d, which showed that C/N ≥ 7 (25 °C) was enough to meet the general discharge standards of NH 4 + -N, TN and COD in China. Even for some special areas of China, the more stringent discharge standards (NH 4 + -N ≤ 8 mg/L, TN ≤ 20 mg/L) could also be achieved under longer HRT of 14 d and C/N ≥ 6. Notably, the COD concentration in effluent could also be well reduced to 50-55 mg/L, without further physical-chemical treatment. This proposed strategy, involving the high-value utilization of food waste, is thus promising for efficient nitrogen removal from mature landfill leachate. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of concentration of dispersed organic matter on optical maturity parameters. Interlaboratory results of the organic matter concentration working group of the ICCP

Energy Technology Data Exchange (ETDEWEB)

Mendonca Filho, J.G.; Kern, M.L.; Mendonca, J.O. [Palynofacies and Organic Facies Laboratory (LAFO), DEGL, IGEO, UFRJ, Cidade Universitaria, Rio de Janeiro (Brazil); Araujo, C.V.; Menezes, T.R.; Souza, I.V.A.F. [Petrobras R and D Center, Rio de Janeiro (Brazil); Borrego, A.G.; Suarez-Ruiz, I. [Instituto Nacional del Carbon, CSIC, Oviedo (Spain); Cook, A.; Ranasinghe, P. [Keiraville Konsultants Pty. Ltd, NSW (Australia); Flores, D. [University of Porto, Departamento de Geologia (Portugal); Hackley, P. [U.S. Geological Survey, MS 956 National Center Reston, VA (United States); Hower, J.C. [University of Kentucky, Center for Applied Energy Research, Lexington (United States); Kommeren, K. [Shell International Exploration and Production, Rijswijk (Netherlands); Kus, J. [Germany Federal Institute for Geosciences and Natural Resources in Geozentrum, Hannover (Germany); Mastalerz, M. [Indiana Geological Survey, Indiana University, Bloomington (United States); Newman, J. [Newman Energy Research Ltd, Christchurch (New Zealand); Ujiie, Y. [Graduate School of Science and Technology, Hirosaki University (Japan)

2010-12-01

The main objective of this work was to study the effect of the kerogen isolation procedures on maturity parameters of organic matter using optical microscopes. This work represents the results of the Organic Matter Concentration Working Group (OMCWG) of the International Committee for Coal and Organic Petrology (ICCP) during the years 2008 and 2009. Four samples have been analysed covering a range of maturity (low and moderate) and terrestrial and marine geological settings. The analyses comprise random vitrinite reflectance measured on both kerogen concentrate and whole rock mounts and fluorescence spectra taken on alginite. Eighteen participants from twelve laboratories from all over the world performed the analyses. Samples of continental settings contained enough vitrinite for participants to record around 50 measurements whereas fewer readings were taken on samples from marine setting. The scatter of results was also larger in the samples of marine origin. Similar vitrinite reflectance values were in general recorded in the whole rock and in the kerogen concentrate. The small deviations of the trend cannot be attributed to the acid treatment involved in kerogen isolation but to reasons related to components identification or to the difficulty to achieve a good polish of samples with high mineral matter content. In samples difficult to polish, vitrinite reflectance was measured on whole rock tended to be lower. The presence or absence of rock fabric affected the selection of the vitrinite population for measurement and this also had an influence in the average value reported and in the scatter of the results. Slightly lower standard deviations were reported for the analyses run on kerogen concentrates. Considering the spectral fluorescence results, it was observed that the {lambda}max presents a shift to higher wavelengths in the kerogen concentrate sample in comparison to the whole-rock sample, thus revealing an influence of preparation methods (acid treatment

Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

Science.gov (United States)

Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

2003-01-01

We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (< 3 nm) optical spectra (350-2500 nm) of reflectance, transmittance, and absorptance were also acquired for both adaxial and abaxial leaf surfaces. Species differences were demonstrated for several optical parameters. A 'red edge' derivative ratio determined from transmittance spectra [as the maximum first deivative, between 650-750 nm, normalized to the value at 744 nm, or Dmax/D744], was strongly associated with the C/N ratio (r(exp 2) = 0.90, P +/- 0.001). This ratio, calculated from reflectance spectra, was inversely related to chlorophyll b content (r(exp 2) = 0.91, P +/- 0.001) as was the ChlF (F685/F740) ratio obtained with 532 nm excitation (r(exp 2) = 0.76, P +/- 0.01). Discrimination of N treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces

Development and validation of a rapid HPLC- fluorescence method for simultaneous determination of venlafaxine and its major metabolites in human plasma

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Y.H Ardakani

2010-06-01

Full Text Available "n Background and the purpose of the study:To develop a simple, rapid and accurate HPLC method for the measurement of the venlafaxine and its main metabolites, O-desmethylvenlafaxine and O,N-didesmethylvenlafaxine in pharmacokinetic studies and therapeutic drug monitoring.Method: Chromatographic separation was achieved with a ChromolithTM Performance RP-18e 100 mm×4.6 mm column equipped with a Fluorescence detectore (λex 200 nm/λem 300 nm The mobile phase of methanol:water (35:65, v/v adjusted to pH 2.5 by phosphoric acid was passed through the column in an isocratic mode at flow rate of 2 ml/min. The sample preparation involved a simple, one-step, extraction with ethyl acetate. "nResults:The calibration curves were linear in the concentration range of 1-300 ng/ml for all analytes (r2 > 0.998. The lower limit of quantification was 1 ng/ml for all analytes. Within and between day precisions in the measurement of quality control (QC of samples were in the range of 1.8-14.1% for all analytes. Conclusion:The developed procedure was used to assess the pharmacokinetics of venlafaxine and its main metabolites following oral administration of 75 mg venlafaxine to a healthy subject.

Dissecting Redox Biology Using Fluorescent Protein Sensors.

Science.gov (United States)

Schwarzländer, Markus; Dick, Tobias P; Meyer, Andreas J; Morgan, Bruce

2016-05-01

Fluorescent protein sensors have revitalized the field of redox biology by revolutionizing the study of redox processes in living cells and organisms. Within one decade, a set of fundamental new insights has been gained, driven by the rapid technical development of in vivo redox sensing. Redox-sensitive yellow and green fluorescent protein variants (rxYFP and roGFPs) have been the central players. Although widely used as an established standard tool, important questions remain surrounding their meaningful use in vivo. We review the growing range of thiol redox sensor variants and their application in different cells, tissues, and organisms. We highlight five key findings where in vivo sensing has been instrumental in changing our understanding of redox biology, critically assess the interpretation of in vivo redox data, and discuss technical and biological limitations of current redox sensors and sensing approaches. We explore how novel sensor variants may further add to the current momentum toward a novel mechanistic and integrated understanding of redox biology in vivo. Antioxid. Redox Signal. 24, 680-712.

Analysis of selected elements in tobacco by wavelength dispersive X-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Martin, J.M.

1988-01-01

A rapid method for the determination of 16 elements in tobacco by wavelength dispersive X-ray fluorescence spectrometry has been developed. The method is accurate and precise, and requires only 9 min per sample for quantitation. Sample preparation consists of placing a portion of dried, ground tobacco in a sample cup, and pressing at 25 tons pressure to make a compressed pellet. This pellet is then automatically analyzed by X-ray fluorescence for 16 elements. The results are stored on a computer disk for future recall and report generation. The elements are: Al, Br, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, S, Si, Sr, Ti and Zn

Highly Sensitive Fluorescent Sensor for Cartap Based on Fluorescence Resonance Energy Transfer Between Gold Nanoparticles and Rhodamine B.

Science.gov (United States)

Dong, Liang; Hou, Changjun; Fa, Huanbao; Yang, Mei; Wu, Huixiang; Zhang, Liang; Huo, Danqun

2018-04-01

Cartap residue poses a great threat to human health and its derivatives would remain in soils, natural waters and other environmental domains for a long time. Herein, a simple, rapid and ultrasensitive analytical method for the determination of cartap based on fluorescence resonance energy transfer (FRET) between Au nanoparticles (AuNPs) and rhodamine B (RB) is first described. With the presence of citrate-stabilized AuNPs, the fluorescence of RB was remarkably quenched by AuNPs via FRET. The fluorescence of the AuNPs-RB system was recovered upon addition of cartap, cartap can be adsorbed on the surface of AuNPs due to its amino group that has good affinity with gold, which could induce the aggregation of AuNPs accompanying color change from red to blue. Thus, the FRET between AuNPs and RB was weakened and the PL intensity of RB was recovered accordingly. A good linear correlation for detection of RB was exhibited from 1 nM to 180 nM, and the detection limit reached 0.88 nM, which was much lower than the safety limit required by USA, UK and China. To the best of our knowledge, it has been the lowest detection ever without the aid of costly instrumentation. This method was successfully carried out for the assessment of cartap in real samples with satisfactory results, which revealed many advantages such as high sensitivity, low cost and non-time-consuming compared with traditional methods.

Relationship between cervical vertebral maturation and mandibular growth.

Science.gov (United States)

Ball, Gina; Woodside, Donald; Tompson, Bryan; Hunter, W Stuart; Posluns, James

2011-05-01

The cervical vertebrae have been proposed as a method of determining biologic maturity. The purposes of this study were to establish a pattern of mandibular growth and to relate this pattern to the stages of cervical vertebral maturation. Cephalometric radiographs, taken annually from ages 9 to 18 years, were evaluated for 90 boys from the Burlington Growth Center, Toronto, Ontario, Canada. Mandibular lengths were measured from articulare to gnathion, and incremental growth was determined. Cervical vertebral maturation stages were assessed by using a 6-stage method. Advanced, average, and delayed maturation groups were established. The prepubertal mandibular growth minimum velocity occurred during cervical stages 1 through 4 (P = 0.7327). Peak mandibular growth velocity occurred most frequently during stage 4 in all 3 maturation groups, with a statistical difference in the average and delayed groups (P cervical stages 1 through 6 does not occur annually; time spent in each stage varies depending on the stage and the maturation group. Cervical vertebral maturation stages cannot accurately identify the mandibular prepubertal growth minimum and therefore cannot predict the onset of the peak in mandibular growth. The cervical vertebral maturation stages should be used with other methods of biologic maturity assessment when considering both dentofacial orthopedic treatment and orthognathic surgery. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Effects of Crocin Supplementation during In Vitro Maturation of Mouse Oocytes on Glutathione Synthesis and Cytoplasmic Maturation

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Elham Mokhber Maleki

2016-05-01

Full Text Available Background: Crocin is an active ingredient of saffron (Crocus sativus L. and its antioxidant properties have been previously investigated. This carotenoid scavenges free radicals and stimulates glutathione (GSH synthesis; consequently, it may protect cells against oxidative stress. The aim of this research is to protect oocytes from oxidative stress by the addition of a natural source antioxidant. Materials and Methods: In the present in vitro experimental study, we collected cumulus oocyte complexes (COCs from mouse ovaries of euthanized, 6-8 week-old female Naval Medical Research Institute (NMRI mice. Oocytes were subjected to in vitro maturation (IVM in the presence of either crocin (5 or 10 μg/ml, 5 mM buthionine-[S-R]- sulfoximine (BSO, or the combination of crocin plus BSO. Oocytes that matured in vitro in a medium without crocin or BSO supplements were considered as controls. Following 16-18 hours of IVM, matured oocytes (n=631 were fertilized by capacitated sperm from NMRI male mice, and cultured in vitro for up to 96 hours to assess preimplantation embryonic development. The levels of GSH in metaphase II (MII oocytes after IVM (n=240 were also assessed by the 5, 5-dithio-bis (2-nitrobenzoic acid (DTNB-GSH reductase recycling assay. Results: Supplementation of IVM media with 10 μg/ml crocin significantly (P<0.05 increased nuclear maturation, preimplantation development and GSH concentrations compared with the control group. Maturation of oocytes in IVM medium supplemented with BSO alone or the combination of 5 μg/ml crocin and BSO drastically decreased GSH concentrations and subsequently resulted in low rates of maturation, fertilization and blastocyst development. However, the combination of 10 μg/ml crocin with 5 mM BSO increased the level of nuclear maturation which was comparable to the control group. Conclusion: Supplementation of IVM media with crocin can improve nuclear maturation rates and subsequent developmental potential

Chromatic aberration correction and deconvolution for UV sensitive imaging of fluorescent sterols in cytoplasmic lipid droplets

DEFF Research Database (Denmark)

Wüstner, Daniel; Faergeman, Nils J

2008-01-01

adipocyte differentiation. DHE is targeted to transferrin-positive recycling endosomes in preadipocytes but associates with droplets in mature adipocytes. Only in adipocytes but not in foam cells fluorescent sterol was confined to the droplet-limiting membrane. We developed an approach to visualize...... macrophage foam cells and in adipocytes. We used deconvolution microscopy and developed image segmentation techniques to assess the DHE content of lipid droplets in both cell types in an automated manner. Pulse-chase studies and colocalization analysis were performed to monitor the redistribution of DHE upon...

Rapid detection of microbial contamination in grape juice by flow cytometry

Directory of Open Access Journals (Sweden)

Marielle Bouix

1999-03-01

Full Text Available This study presents an application of flow cytometry to evaluate rapidly the viable micro-organisms in grape juice. In this method, viable cells are firstly specitically labelled with a fluorescent reagent. The sample is then injected into the flow cytometer where the labelled micro-organisms are individually illuminated by a laser beam. The emission of fluorescence is measured. The system counts the number of fluorescent events and prints out a histogram of the fluorescence intensity which is characteristic of the micro-organism being analysed. In laboratory conditions, preliminary trials have been undertaken with an artificially inoculated grape juice with pure yeast and bacteria cultures. This method succeeded in counting simultaneously yeasts and bacteria within 15 minutes, with a high degree of sensitivity, 5.103 yeasts perml and 5.104 bacteria per ml. This technique can also be applied to the detection of mould contamination and the test has been done with Botrytis spores. The method makes direct cell counts possible and is capable of analysing 30 samples per hour. It can be automatised and easily used in industrial laboratory. During the last harvest, more than a thousand of must samples were controled using this technique. The results let to determine the yeast contamination level of a grape juice tank even before unloading. The results obtained by flow cytometry were compared to the plate count reference method. The correlation between cytometry and count by plate culture was 99 p. cent for the threshold of 5.1 04 yeasts/ml which seemed to point out a high contamination. By using this flow cytometry method during the harvest period, the results were supplied in real time. This allowed a rapid selection of the musts, depending upon the scale of their contamination and improved the quality of the wine by corrective actions.

Fluorescent Probes and Fluorescence (Microscopy Techniques — Illuminating Biological and Biomedical Research

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Gregor P. C. Drummen

2012-11-01

Full Text Available Fluorescence, the absorption and re-emission of photons with longer wavelengths, is one of those amazing phenomena of Nature. Its discovery and utilization had, and still has, a major impact on biological and biomedical research, since it enables researchers not just to visualize normal physiological processes with high temporal and spatial resolution, to detect multiple signals concomitantly, to track single molecules in vivo, to replace radioactive assays when possible, but also to shed light on many pathobiological processes underpinning disease states, which would otherwise not be possible. Compounds that exhibit fluorescence are commonly called fluorochromes or fluorophores and one of these fluorescent molecules in particular has significantly enabled life science research to gain new insights in virtually all its sub-disciplines: Green Fluorescent Protein. Because fluorescent proteins are synthesized in vivo, integration of fluorescent detection methods into the biological system via genetic techniques now became feasible. Currently fluorescent proteins are available that virtually span the whole electromagnetic spectrum. Concomitantly, fluorescence imaging techniques were developed, and often progress in one field fueled innovation in the other. Impressively, the properties of fluorescence were utilized to develop new assays and imaging modalities, ranging from energy transfer to image molecular interactions to imaging beyond the diffraction limit with super-resolution microscopy. Here, an overview is provided of recent developments in both fluorescence imaging and fluorochrome engineering, which together constitute the “fluorescence toolbox” in life science research.

Direct Induction and Functional Maturation of Forebrain GABAergic Neurons from Human Pluripotent Stem Cells

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Alfred Xuyang Sun

2016-08-01

Full Text Available Gamma-aminobutyric acid (GABA-releasing interneurons play an important modulatory role in the cortex and have been implicated in multiple neurological disorders. Patient-derived interneurons could provide a foundation for studying the pathogenesis of these diseases as well as for identifying potential therapeutic targets. Here, we identified a set of genetic factors that could robustly induce human pluripotent stem cells (hPSCs into GABAergic neurons (iGNs with high efficiency. We demonstrated that the human iGNs express neurochemical markers and exhibit mature electrophysiological properties within 6–8 weeks. Furthermore, in vitro, iGNs could form functional synapses with other iGNs or with human-induced glutamatergic neurons (iENs. Upon transplantation into immunodeficient mice, human iGNs underwent synaptic maturation and integration into host neural circuits. Taken together, our rapid and highly efficient single-step protocol to generate iGNs may be useful to both mechanistic and translational studies of human interneurons.

A sensitive fluorescence quenching method for determination of bismuth with tiron

Energy Technology Data Exchange (ETDEWEB)

Taher, Mohammad Ali; Rahimi, Mina [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Fazelirad, Hamid, E-mail: hamidfazelirad@gmail.com [Department of Chemistry, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Department of Chemistry, Science and Research Branch, Islamic Azad University, Yazd (Iran, Islamic Republic of); Young Researchers Society, Shahid Bahonar University of Kerman, P.O. Box 76175-133, Kerman (Iran, Islamic Republic of)

2014-01-15

We describe a fluorescence quenching method for determination of bismuth with tiron. The method is based on the reaction of tiron by bismuth(III) in acidic media. The influence of variables such as the pH, type of buffer, tiron concentration, reaction time and temperature were investigated. Under optimized conditions, the fluorescence quenching extent is proportional to the concentration of bismuth for Bi–tiron system at the range 0.13–2.09 μg mL{sup −1} and the detection limit is 0.05 μg mL{sup −1}. The proposed sensor presented good repeatability, evaluated in terms of relative standard deviation (R.S.D.=±0.498%) for 11 replicates. This sensitive, rapid and accurate method has been successfully applied to the determination of trace bismuth(III) in water and hair samples and certified reference materials. -- Highlights: • No previous paper report on use of fluorescence quenching for determination of Bi. • Fluorescence quenching of trion is a sensitive method for determination of Bi(III). • Under the optimum conditions the detection limit is very low (0.05 μg mL{sup −1}). • The procedure is simple and safe and has high tolerance limit to interferences.

Specific detection of Vibrio parahaemolyticus by fluorescence quenching immunoassay based on quantum dots.

Science.gov (United States)

Wang, Ling; Zhang, Junxian; Bai, Haili; Li, Xuan; Lv, Pintian; Guo, Ailing

2014-07-01

In this study, anti-Vibrio parahaemolyticus polyclonal and monoclonal antibodies were prepared through intradermal injection immune and lymphocyte hybridoma technique respectively. CdTe quantum dots (QDs) were synthesized at pH 9.3, 98 °C for 1 h with stabilizer of 2.7:1. The fluorescence intensity was 586.499, and the yield was 62.43%. QD probes were successfully prepared under the optimized conditions of pH 7.4, 37 °C for 1 h, 250 μL of 50 mg/mL EDC · HCl, 150 μL of 4 mg/mL NHS, buffer system of Na2HPO4-citric acid, and 8 μL of 2.48 mg/mL polyclonal antibodies. As gold nanoparticles could quench fluorescence of quantum dots, the concentration of V. parahaemolyticus could be detected through measuring the reduction of fluorescence intensity in immune sandwich reaction composed of quantum dot probe, gold-labeled antibody, and the sample. For pure culture, fluorescence intensity of the system was proportional with logarithm concentration of antigen, and the correlation coefficient was 99.764%. The fluorescence quenching immunoassay based on quantum dots is established for the first time to detect Vibrio parahaemolyticus. This method may be used as rapid testing procedure due to its high simplicity and sensitivity.

Development of a green fluorescent protein metastatic-cancer chick-embryo drug-screen model.

Science.gov (United States)

Bobek, Vladimir; Plachy, Jiri; Pinterova, Daniela; Kolostova, Katarina; Boubelik, Michael; Jiang, Ping; Yang, Meng; Hoffman, Robert M

2004-01-01

The chick-embryo model has been an important tool to study tumor growth, metastasis, and angiogenesis. However, an imageable model with a genetic fluorescent tag in the growing and spreading cancer cells that is stable over time has not been developed. We report here the development of such an imageable fluorescent chick-embryo metastatic cancer model with the use of green fluorescent protein (GFP). Lewis lung carcinoma cells, stably expressing GFP, were injected on the 12th day of incubation in the chick embryo. GFP-Lewis lung carcinoma metastases were visualized by fluorescence, after seven days additional incubation, in the brain, heart, and sternum of the developing chick embryo, with the most frequent site being the brain. The combination of streptokinase and gemcitabine was evaluated in this GFP metastatic model. Twelve-day-old chick embryos were injected intravenously with GFP-Lewis lung cancer cells, along with these two agents either alone or in combination. The streptokinase-gemcitabine combination inhibited metastases at all sites. The effective dose of gemcitabine was found to be 10 mg/kg and streptokinase 2000 IU per embryo. The data in this report suggest that this new stably fluorescent imageable metastatic-cancer chick-embryo model will enable rapid screening of new antimetastatic agents.

The structure of mAG, a monomeric mutant of the green fluorescent protein Azami-Green, reveals the structural basis of its stable green emission

International Nuclear Information System (INIS)

Ebisawa, Tatsuki; Yamamura, Akihiro; Kameda, Yasuhiro; Hayakawa, Kou; Nagata, Koji; Tanokura, Masaru

2010-01-01

The crystal structure of a monomeric mutant of Azami-Green (mAG) from G. fascicularis was determined at 2.2 Å resolution. Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first known monomeric green-emitting fluorescent protein that is not a variant of Aequorea victoria green fluorescent protein (avGFP). These two green fluorescent proteins are only 27% identical in their amino-acid sequences. mAG is more similar in its amino-acid sequence to four fluorescent proteins: Dendra2 (a green-to-red irreversibly photoconverting fluorescent protein), Dronpa (a bright-and-dark reversibly photoswitchable fluorescent protein), KikG (a tetrameric green-emitting fluorescent protein) and Kaede (another green-to-red irreversibly photoconverting fluorescent protein). To reveal the structural basis of stable green emission by mAG, the 2.2 Å crystal structure of mAG has been determined and compared with the crystal structures of avGFP, Dronpa, Dendra2, Kaede and KikG. The structural comparison revealed that the chromophore formed by Gln62-Tyr63-Gly64 (QYG) and the fixing of the conformation of the imidazole ring of His193 by hydrogen bonds and van der Waals contacts involving His193, Arg66 and Thr69 are likely to be required for the stable green emission of mAG. The crystal structure of mAG will contribute to the design and development of new monomeric fluorescent proteins with faster maturation, brighter fluorescence, improved photostability, new colours and other preferable properties as alternatives to avGFP and its variants

Reusable Xerogel Containing Quantum Dots with High Fluorescence Retention

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Xiang-Yong Liang

2018-03-01

Full Text Available Although various analytical methods have been established based on quantum dots (QDs, most were conducted in solution, which is inadequate for storage/transportation and rapid analysis. Moreover, the potential environmental problems caused by abandoned QDs cannot be ignored. In this paper, a reusable xerogel containing CdTe with strong emission is established by introducing host–guest interactions between QDs and polymer matrix. This xerogel shows high QDs loading capacity without decrease or redshift in fluorescence (the maximum of loading is 50 wt % of the final xerogel, which benefits from the steric hindrance of β-cyclodextrin (βCD molecules. Host–guest interactions immobilize QDs firmly, resulting in the excellent fluorescence retention of the xerogel. The good detecting performance and reusability mean this xerogel could be employed as a versatile analysis platform (for quantitative and qualitative analyses. In addition, the xerogel can be self-healed by the aid of water.

Highly selective and sensitive detection of Cu2+ with lysine enhancing bovine serum albumin modified-carbon dots fluorescent probe.

Science.gov (United States)

Liu, Jia-Ming; Lin, Li-ping; Wang, Xin-Xing; Lin, Shao-Qin; Cai, Wen-Lian; Zhang, Li-Hong; Zheng, Zhi-Yong

2012-06-07

Based on the ability of lysine (Lys) to enhance the fluorescence intensity of bovine serum albumin modified-carbon dots (CDs-BSA) to decrease surface defects and quench fluorescence of the CDs-BSA-Lys system in the presence of Cu(2+) under conditions of phosphate buffer (PBS, pH = 5.0) at 45 °C for 10 min, a sensitive Lys enhancing CDs-BSA fluorescent probe was designed. The environment-friendly, simple, rapid, selective and sensitive fluorescent probe has been utilized to detect Cu(2+) in hair and tap water samples and it achieved consistent results with those obtained by inductively coupled plasma mass spectroscopy (ICP-MS). The mechanism of the proposed assay for the detection of Cu(2+) is discussed.

Reviews in fluorescence 2010

CERN Document Server

Geddes, Chris D

2011-01-01

""Reviews in Fluorescence 2010"", the seventh volume of the book serial from Springer, serves as a comprehensive collection of current trends and emerging hot topics in the field of fluorescence and closely related disciplines. It summarizes the year's progress in fluorescence and its applications, with authoritative analytical reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. ""Reviews in Fluorescence"" offers an essential reference material for any lab working in the fluoresc

Micellar Enhanced Three-Dimensional Excitation-Emission Matrix Fluorescence for Rapid Determination of Antihypertensives in Human Plasma with Aid of Second-Order Calibration Methods

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Hai-Yan Fu

2015-01-01

Full Text Available A highly sensitive three-dimensional excitation-emission fluorescence method was proposed to determine antihypertensives including valsartan and amlodipine besylate in human plasma with the aid of second-order calibration methods based on parallel factor analysis (PARAFAC and alternating trilinear decomposition (ATLD algorithms. Antihypertensives with weak fluorescent can be transformed into a strong fluorescent property by changing microenvironment in samples using micellar enhanced surfactant. Both the adopted algorithms with second-order advantage can improve the resolution and directly attain antihypertensives concentration even in the presence of potential strong intrinsic fluorescence from human plasma. The satisfactory results can be achieved for valsartan and amlodipine besylate in complicated human plasma. Furthermore, some statistical parameters and figures of merit were evaluated to investigate the performance of the proposed method, and the accuracy and precision of the proposed method were also validated by the elliptical joint confidence region (EJCR test and repeatability analysis of intraday and interday assay. The proposed method could not only light a new avenue to directly determine valsartan or amlodipine besylate in human plasma, but also hold great potential to be extended as a promising alternative for more practical applications in the determination of weak fluorescent drugs.

A method for detection of hydroxyl radicals in the vicinity of biomolecules using radiation-induced fluorescence of coumarin

International Nuclear Information System (INIS)

Makrigiorgos, G.M.; Baranowska-Kortylewicz, J.; Bump, E.; Sahu, S.K.; Berman, R.M.; Kassis, A.I.

1993-01-01

A novel method is described to quantitate radiation-induced hydroxyl radicals in the vicinity of biomolecules in aqueous solutions. Coumarin-3-carboxylic acid (CCA) is a non-fluorescent molecule that, upon interaction with radiation in aqueous solution, produces fluorescent products. CCA was derivatized to its succinimidyl ester (SECCA) and coupled to free primary amines of albumin, avidin, histone-H1, polylysine, and an oligonucleotide. When SECCA-biomolecule conjugates were irradiated, the relationship between induced fluorescence and dose was linear in the dose range examined (0.01-10 Gy). The data indicate that the induction of fluorescence on SECCA-biomolecule conjugates records specifically the presence of the hydroxyl radical in the immediate vicinity of the irradiated biomolecule. The method is rapid and sensitive, uses standard instrumentation, and the sample remains available for further studies. (Author)

Using the Maturity Method in Predicting the Compressive Strength of Vinyl Ester Polymer Concrete at an Early Age

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Nan Ji Jin

2017-01-01

Full Text Available The compressive strength of vinyl ester polymer concrete is predicted using the maturity method. The compressive strength rapidly increased until the curing age of 24 hrs and thereafter slowly increased until the curing age of 72 hrs. As the MMA content increased, the compressive strength decreased. Furthermore, as the curing temperature decreased, compressive strength decreased. For vinyl ester polymer concrete, datum temperature, ranging from −22.5 to −24.6°C, decreased as the MMA content increased. The maturity index equation for cement concrete cannot be applied to polymer concrete and the maturity of vinyl ester polymer concrete can only be estimated through control of the time interval Δt. Thus, this study introduced a suitable scaled-down factor (n for the determination of polymer concrete’s maturity, and a factor of 0.3 was the most suitable. Also, the DR-HILL compressive strength prediction model was determined as applicable to vinyl ester polymer concrete among the dose-response models. For the parameters of the prediction model, applying the parameters by combining all data obtained from the three different amounts of MMA content was deemed acceptable. The study results could be useful for the quality control of vinyl ester polymer concrete and nondestructive prediction of early age strength.

The pattern of auditory brainstem response wave V maturation in cochlear-implanted children.

Science.gov (United States)

Thai-Van, Hung; Cozma, Sebastian; Boutitie, Florent; Disant, François; Truy, Eric; Collet, Lionel

2007-03-01

. Maturational time-course for the ABR in preterm and full term infants. Hear Res 33, 35-47; Eggermont, J.J., Salamy, A., 1988b. Development of ABR parameters in a preterm and a term born population. Ear Hear 9, 283-9] of normal hearing children: a sum of two decaying exponential functions, one showing an early rapid decrease in latency and the other a slower decrease. Remarkably, the time-constants fell well within the ranges described by Eggermont and Salamy (i.e., 3.9 and 68 weeks), consistent with the time-course of the neurophysiological mechanisms presumably involved in auditory pathway maturation during the first 2 years of life: i.e., myelination and increased synaptic efficacy. In contrast, relatively little change in wave V was evident in children with late-onset deafness. In agreement with the notion that EABR maturation follows an apex-to-base gradient as described for ABR, we observed that wave V latencies were longer for the basal than the apical end of the implant electrode array and remained so throughout the study period, whatever the time of onset of deafness. The findings in the early-onset of deafness group support the theory that auditory pathways remain "frozen" during the period of sensory deprivation until cochlear implant rehabilitation restores the normal chronology of maturational processes. In children with late-onset deafness, however, some maturational processes may occur before the onset of deafness, and thus less additional maturation is required during the first two years of implant use resulting in no significant EABR latency changes being observed in this period. The results suggest that the rehabilitation-induced plasticity of the auditory pathways is, in case of late auditory deprivation, unlikely to result in neurophysiological outcomes similar to those observed in children with early auditory deprivation. Changes in EABR wave V latency over the first 2 years of cochlear implant use were found to be well fitted by the sum of two decaying

Chlorophyll fluorescence lifetime imaging provides new insight into the chlorosis induced by plant virus infection.

Science.gov (United States)

Lei, Rong; Jiang, Hongshan; Hu, Fan; Yan, Jin; Zhu, Shuifang

2017-02-01

Leaf chlorosis induced by plant virus infection has a short fluorescence lifetime, which reflects damaged photosynthetic complexes and degraded chloroplasts. Plant viruses often induce chlorosis and necrosis, which are intimately related to photosynthetic functions. Chlorophyll fluorescence lifetime measurement is a valuable noninvasive tool for analyzing photosynthetic processes and is a sensitive indicator of the environment surrounding the fluorescent molecules. In this study, our central goal was to explore the effect of viral infection on photosynthesis by employing chlorophyll fluorescence lifetime imaging (FLIM), steady-state fluorescence, non-photochemical quenching (NPQ), transmission electron microscopy (TEM), and pigment analysis. The data indicated that the chlorophyll fluorescence lifetime of chlorotic leaves was significantly shorter than that of healthy control leaves, and the fitted short lifetime component of chlorophyll fluorescence of chlorotic leaves was dominant. This dominant short lifetime component may result from damage to the structure of thylakoid, which was confirmed by TEM. The NPQ value of chlorotic leaves was slightly higher than that of healthy green leaves, which can be explained by increased neoxanthin, lutein and violaxanthin content relative to chlorophyll a. The difference in NPQ is slight, but FLIM can provide simple and direct characterization of PSII structure and photosynthetic function. Therefore, this technique shows great potential as a simple and rapid method for studying mechanisms of plant virus infection.

Dual-Color Fluorescence Imaging of Magnetic Nanoparticles in Live Cancer Cells Using Conjugated Polymer Probes

Science.gov (United States)

Sun, Minjie; Sun, Bin; Liu, Yun; Shen, Qun-Dong; Jiang, Shaojun

2016-01-01

Rapid growth in biological applications of nanomaterials brings about pressing needs for exploring nanomaterial-cell interactions. Cationic blue-emissive and anionic green-emissive conjugated polymers are applied as dual-color fluorescence probes to the surface of negatively charged magnetic nanoparticles through sequentially electrostatic adsorption. These conjugated polymers have large extinction coefficients and high fluorescence quantum yield (82% for PFN and 62% for ThPFS). Thereby, one can visualize trace amount (2.7 μg/mL) of fluorescence-labeled nanoparticles within cancer cells by confocal laser scanning microscopy. Fluorescence labeling by the conjugated polymers is also validated for quantitative determination of the internalized nanoparticles in each individual cell by flow cytometry analysis. Extensive overlap of blue and green fluorescence signals in the cytoplasm indicates that both conjugated polymer probes tightly bind to the surface of the nanoparticles during cellular internalization. The highly charged and fluorescence-labeled nanoparticles non-specifically bind to the cell membranes, followed by cellular uptake through endocytosis. The nanoparticles form aggregates inside endosomes, which yields a punctuated staining pattern. Cellular internalization of the nanoparticles is dependent on the dosage and time. Uptake efficiency can be enhanced three-fold by application of an external magnetic field. The nanoparticles are low cytotoxicity and suitable for simultaneously noninvasive fluorescence and magnetic resonance imaging application. PMID:26931282

7 CFR 1421.101 - Maturity dates.

Science.gov (United States)

2010-01-01

... filed and disbursed except, for transferred marketing assistance loan collateral. The maturity date for transferred marketing assistance loan collateral will be the maturity date applicable to the original loan... AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS GRAINS AND SIMILARLY HANDLED COMMODITIES-MARKETING...

A Systematic Literature Review of Agile Maturity Model Research

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Vaughan Henriques

2017-02-01

Full Text Available Background/Aim/Purpose: A commonly implemented software process improvement framework is the capability maturity model integrated (CMMI. Existing literature indicates higher levels of CMMI maturity could result in a loss of agility due to its organizational focus. To maintain agility, research has focussed attention on agile maturity models. The objective of this paper is to find the common research themes and conclusions in agile maturity model research. Methodology: This research adopts a systematic approach to agile maturity model research, using Google Scholar, Science Direct, and IEEE Xplore as sources. In total 531 articles were initially found matching the search criteria, which was filtered to 39 articles by applying specific exclusion criteria. Contribution:: The article highlights the trends in agile maturity model research, specifically bringing to light the lack of research providing validation of such models. Findings: Two major themes emerge, being the coexistence of agile and CMMI and the development of agile principle based maturity models. The research trend indicates an increase in agile maturity model articles, particularly in the latter half of the last decade, with concentrations of research coinciding with version updates of CMMI. While there is general consensus around higher CMMI maturity levels being incompatible with true agility, there is evidence of the two coexisting when agile is introduced into already highly matured environments. Future Research:\tFuture research direction for this topic should include how to attain higher levels of CMMI maturity using only agile methods, how governance is addressed in agile environments, and whether existing agile maturity models relate to improved project success.

Customer-Provider Strategic Alignment: A Maturity Model

Science.gov (United States)

Luftman, Jerry; Brown, Carol V.; Balaji, S.

This chapter presents a new model for assessing the maturity of a ­customer-provider relationship from a collaborative service delivery perspective: the Customer-Provider Strategic Alignment Maturity (CPSAM) Model. This model builds on recent research for effectively managing the customer-provider relationship in IT service outsourcing contexts and a validated model for assessing alignment across internal IT service units and their business customers within the same organization. After reviewing relevant literature by service science and information systems researchers, the six overarching components of the maturity model are presented: value measurements, governance, partnership, communications, human resources and skills, and scope and architecture. A key assumption of the model is that all of the components need be addressed to assess and improve customer-provider alignment. Examples of specific metrics for measuring the maturity level of each component over the five levels of maturity are also presented.

Modification of the Rappaport rapid test in large-scale testing for syphilis. Evaluation of the rapid plate and rapid card tests.

Science.gov (United States)

Ghinsberg, R; Meir, E; Blumstein, G; Kafeman, R

1975-11-01

The Rappaport rapid (RR) plate and card tests were developed as modifications of the RR tube test to permit rapid and inexpensive screening of large numbers of subjects for the diagnosis of syphilis. More than 2,000 sera were examined in parallel by the Venereal Disease Research Laboratory (VDRL) slide test, the rapid plasma reagin (RPR) card test and the RR plate and card tests. There was complete agreement between the RR plate and card tests and the VDRL slide and RPR card tests in 96.6% of sera. In a selected group of 1,530 sera examined, in addition, by the fluorescent treponemal antibody absorption (FTA-ABS) test, there was agreement between the RR plate and card tests and the FTA-ABS test in 74.3% of sera and between the VDRL and RPR tests and the FTA-ABS test in 73.7% of sera. The RR plate test was found to be sufficiently sensitive and specific for the diagnosis of syphilis, although the VDRL slide test is perhaps more sensitive in primary and late latent syphilis. Since the antigen used in the RR tests is colored and stable and the sera do not require inactivation before the test, the tests are easier to perform than the VDRL slide test: the RR plate and card tests could therefore replace the VDRL test as a screening test, with hardly any loss of accuracy.

Maturation of the human fetal startle response: Evidence for sex-specific maturation of the human fetus1

Science.gov (United States)

Buss, Claudia; Davis, Elysia Poggi; Class, Quetzal A.; Gierczak, Matt; Pattillo, Carol; Glynn, Laura M.; Sandman, Curt A.

2009-01-01

Despite the evidence for early fetal experience exerting programming influences on later neurological development and health risk, very few prospective studies of human fetal behavior have been reported. In a prospective longitudinal study, fetal nervous system maturation was serially assessed by monitoring fetal heart rate (FHR) responses to vibroacoustic stimulation (VAS) in 191 maternal/fetal dyads. Responses were not detected at 26 weeks gestational age (GA). Sex-specific, age-characteristic changes in the FHR response to VAS were observed by 31 weeks’ GA. Males showed larger responses and continued to exhibit maturational changes until 37 weeks’ GA, females however, presented with a mature FHR startle response by 31 weeks’ GA. The results indicate that there are different rates of maturation in the male and female fetus that may have implications for sex-specific programming influences. PMID:19726143

Rab20 regulates phagosome maturation in RAW264 macrophages during Fc gamma receptor-mediated phagocytosis.

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Youhei Egami

Full Text Available Rab20, a member of the Rab GTPase family, is known to be involved in membrane trafficking, however its implication in FcγR-mediated phagocytosis is unclear. We examined the spatiotemporal localization of Rab20 during phagocytosis of IgG-opsonized erythrocytes (IgG-Es in RAW264 macrophages. By the live-cell imaging of fluorescent protein-fused Rab20, it was shown that Rab20 was transiently associated with the phagosomal membranes. During the early stage of phagosome formation, Rab20 was not localized on the membranes of phagocytic cups, but was gradually recruited to the newly formed phagosomes. Although Rab20 was colocalized with Rab5 to some extent, the association of Rab20 with the phagosomes persisted even after the loss of Rab5 from the phagosomal membranes. Then, Rab20 was colocalized with Rab7 and Lamp1, late endosomal/lysosomal markers, on the internalized phagosomes. Moreover, our analysis of Rab20 mutant expression revealed that the maturation of phagosomes was significantly delayed in cells expressing the GDP-bound mutant Rab20-T19N. These data suggest that Rab20 is an important component of phagosome and regulates the phagosome maturation during FcγR-mediated phagocytosis.

Application of portable XRF and VNIR sensors for rapid assessment of soil heavy metal pollution

OpenAIRE

Hu, Bifeng; Chen, Songchao; Hu, Jie; Xia, Fang; Xu, Junfeng; Li, Yan; Shi, Zhou

2017-01-01

Rapid heavy metal soil surveys at large scale with high sampling density could not be conducted with traditional laboratory physical and chemical analyses because of the high cost, low efficiency and heavy workload involved. This study explored a rapid approach to assess heavy metals contamination in 301 farmland soils from Fuyang in Zhejiang Province, in the southern Yangtze River Delta, China, using portable proximal soil sensors. Portable X-ray fluorescence spectroscopy (PXRF) was used to ...

A correlative study of dental age and skeletal maturation.

Science.gov (United States)

Sachan, Kiran; Sharma, Vijay Prakash; Tandon, Pradeep

2011-01-01

Skeletal age had been assessed by comparison between maturation of hand-wrist with stages of cervical vertebrae or canine calcification stages in past and this had been closely related to craniofacial growth. The importance of pubertal growth spurt in various types of orthodontic therapies is already established. Hence, this study was aimed to evaluate the relationship of skeletal maturity by hand-wrist with cervical vertebral maturation indicators and canine calcification stages. The study consisted of randomly selected 90 children from Lucknow population with 45 males (age range 10-13 years) and 45 females (age range 9-12 years). Lateral Cephalogram, hand-wrist x-ray, and periapical x-rays of maxillary and mandibular right canines were taken. Mean, standard deviation was calculated of different groups. Correlation was made among cervical vertebral maturation, hand wrist maturation, and canine calcification stages at various age groups. There was strong correlation between skeletal maturation indicator and cervical vertebral maturation indicator for both male (0.849) and female (0.932), whereas correlation between skeletal maturation indicator and canine calcification was good for both male and female (0.635, 0.891). It was concluded that cervical vertebral maturation indicator and canine calcification stages can also be used for assessing skeletal maturity.

[Evaluation of fetal lung maturity using a modified lecithin-sphingomyelin determination and Clements' foam test].

Science.gov (United States)

Neumann, G; Gartzke, J; Faber, G

1978-01-01

The modified thin layer chromatographic method for the determination of the phospholipids lecithin and sphingomyelin from amniotic fluid is useful in estimating fetal pulmonary maturity. The foam test of Clements is a simple rapid method for screening of suspicious cases of pregnancies at risk and of great value as bed side test even performing by the doctor. In comparing Clements-Test with thin layer chromatographic for L/S-Ratio determination we found a good correlation of 81,8% of all cases.

Maturation of sugar maple seed

Science.gov (United States)

Clayton M., Jr. Carl; Albert G., Jr. Snow; Albert G. Snow

1971-01-01

The seeds of a sugar maple tree (Acer saccharum Marsh.) do not mature at the same time every year. And different trees mature their seeds at different times. So time of year is not a reliable measure of when seeds are ripe. Better criteria are needed. In recent studies we have found that moisture content and color are the best criteria for judging when sugar maple...

CRISPR/Cas9-Mediated Fluorescent Tagging of Endogenous Proteins in Human Pluripotent Stem Cells.

Science.gov (United States)

Sharma, Arun; Toepfer, Christopher N; Ward, Tarsha; Wasson, Lauren; Agarwal, Radhika; Conner, David A; Hu, Johnny H; Seidman, Christine E

2018-01-24

Human induced pluripotent stem cells (hiPSCs) can be used to mass produce surrogates of human tissues, enabling new advances in drug screening, disease modeling, and cell therapy. Recent developments in clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing technology use homology-directed repair (HDR) to efficiently generate custom hiPSC lines harboring a variety of genomic insertions and deletions. Thus, hiPSCs that encode an endogenous protein fused to a fluorescent reporter protein can be rapidly created by employing CRISPR/Cas9 genome editing, enhancing HDR efficiency and optimizing homology arm length. These fluorescently tagged hiPSCs can be used to visualize protein function and dynamics in real time as cells proliferate and differentiate. Given that nearly any intracellular protein can be fluorescently tagged, this system serves as a powerful tool to facilitate new discoveries across many biological disciplines. In this unit, we present protocols for the design, generation, and monoclonal expansion of genetically customized hiPSCs encoding fluorescently tagged endogenous proteins. © 2018 by John Wiley & Sons, Inc. Copyright © 2018 John Wiley & Sons, Inc.

Fluorescence-enhanced optical imaging in large tissue volumes using a gain-modulated ICCD camera

International Nuclear Information System (INIS)

Godavarty, Anuradha; Eppstein, Margaret J; Zhang, Chaoyang; Theru, Sangeeta; Thompson, Alan B; Gurfinkel, Michael; Sevick-Muraca, Eva M

2003-01-01

A novel image-intensified charge-coupled device (ICCD) imaging system has been developed to perform 3D fluorescence tomographic imaging in the frequency-domain using near-infrared contrast agents. The imager is unique since it (i) employs a large tissue-mimicking phantom, which is shaped and sized to resemble a female breast and part of the extended chest-wall region, and (ii) enables rapid data acquisition in the frequency-domain by using a gain-modulated ICCD camera. Diffusion model predictions are compared to experimental measurements using two different referencing schemes under two different experimental conditions of perfect and imperfect uptake of fluorescent agent into a target. From these experimental measurements, three-dimensional images of fluorescent absorption were reconstructed using a computationally efficient variant of the approximate extended Kalman filter algorithm. The current work represents the first time that 3D fluorescence-enhanced optical tomographic reconstructions have been achieved from experimental measurements of the time-dependent light propagation on a clinically relevant breast-shaped tissue phantom using a gain-modulated ICCD camera

Assessing organisational governance maturity: A retail industry case study

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Hendrik Marius Wessels

2016-05-01

Full Text Available For any business to operate effectively, a governance framework that operates at the relevant maturity level is required. An organisational governance maturity framework is a tool that leadership can use to determine governance maturity. This study aims to determine whether the organisational governance maturity framework (developed by Wilkinson can be applied to the selected retail industry organisation to assess the maturity of the organisation’s governance, limited to the ‘leadership’ attribute. Firstly, a high-level literature review on ethical leadership, ethical decision-making, ethical foundation and culture (‘tone at the top’, and organisational governance and maturity was conducted. Secondly, a Johannesburg Stock Exchange (JSE listed South African-based company was selected for the empirical part of the study using a single case study research design. The empirical results confirmed that the organisational governance maturity framework can be used to determine the maturity level of organisational governance for the selected attribute of ‘leadership’

Preservation of protein fluorescence in embedded human dendritic cells for targeted 3D light and electron microscopy.

Science.gov (United States)

Höhn, K; Fuchs, J; Fröber, A; Kirmse, R; Glass, B; Anders-Össwein, M; Walther, P; Kräusslich, H-G; Dietrich, C

2015-08-01

In this study, we present a correlative microscopy workflow to combine detailed 3D fluorescence light microscopy data with ultrastructural information gained by 3D focused ion beam assisted scanning electron microscopy. The workflow is based on an optimized high pressure freezing/freeze substitution protocol that preserves good ultrastructural detail along with retaining the fluorescence signal in the resin embedded specimens. Consequently, cellular structures of interest can readily be identified and imaged by state of the art 3D confocal fluorescence microscopy and are precisely referenced with respect to an imprinted coordinate system on the surface of the resin block. This allows precise guidance of the focused ion beam assisted scanning electron microscopy and limits the volume to be imaged to the structure of interest. This, in turn, minimizes the total acquisition time necessary to conduct the time consuming ultrastructural scanning electron microscope imaging while eliminating the risk to miss parts of the target structure. We illustrate the value of this workflow for targeting virus compartments, which are formed in HIV-pulsed mature human dendritic cells. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

Smartphone-based fluorescence spectroscopy device aiding in preliminary skin screening

Science.gov (United States)

Sahoo, Aparajita; Wahi, Akshat; Das, Anshuman

2018-02-01

Preliminary diagnosis of closely resembling skin conditions can be highly subjective for dermatologists. In ambiguous cases, it often leads to performing invasive procedures like biopsies. Different skin conditions, however, have varying concentrations of fluorophores (like collagen, NADH) and chromophores (like melanin, hemoglobin) which can alter their fluorescence spectra. We demonstrate a handheld, portable, smartphone-based spectrometer that leverages these alterations in skin autofluorescence spectra for rapid screening of skin conditions. This methodology involves excitation of affected skin areas with ultraviolet (UV-A) 385 nm light, capturing the generated fluorescence spectra and sending the data wirelessly to a companion mobile application for data storage, analysis and visualization. By collecting the fluorescence spectral signals from healthy and unhealthy skin conditions, we establish that the signals collected using this portable device can be used to develop a classification method to help in differentially diagnosing these conditions. It shows promise as a useful skin screening tool for both dermatologists and primary health care workers. This device can enable quick, non-invasive and a more objective preliminary examination. We envision the device to be especially useful in primary healthcare centers of developing countries where availability of dermatologists is limited.

Principles of fluorescence techniques

CERN Document Server

2016-01-01

Fluorescence techniques are being used and applied increasingly in academics and industry. The Principles of Fluorescence Techniques course will outline the basic concepts of fluorescence techniques and the successful utilization of the currently available commercial instrumentation. The course is designed for students who utilize fluorescence techniques and instrumentation and for researchers and industrial scientists who wish to deepen their knowledge of fluorescence applications. Key scientists in the field will deliver theoretical lectures. The lectures will be complemented by the direct utilization of steady-state and lifetime fluorescence instrumentation and confocal microscopy for FLIM and FRET applications provided by leading companies.

Towards a Sustainable Design for Maturity Measurement Marketplace

DEFF Research Database (Denmark)

Lasrado, Lester; Vatrapu, Ravi; Kærsgaard, Henrik Bjerre

2016-01-01

In this research-in-progress paper, we propose a solution in form of an IT artefact to address both theoretical and practical challenges faced by maturity model designers. We identify and list out the existing challenges & criticisms of maturity models research through an extensive literature...... review, followed by semi-structured interviews with four maturity model designers. We also explore different motivations of building a maturity model, and using them further scope the boundaries of our solution....

The potential of a fluorescent-based approach for bioassay of antifungal agents against chili anthracnose disease in Thailand.

Science.gov (United States)

Chutrakul, Chanikul; Khaokhajorn, Pratoomporn; Auncharoen, Patchanee; Boonruengprapa, Tanapong; Mongkolporn, Orarat

2013-01-01

Severe chili anthracnose disease in Thailand is caused by Colletotrichum gloeosporioides and C. capsici. To discover anti-anthracnose substances we developed an efficient dual-fluorescent labeling bioassay based on a microdilution approach. Indicator strains used in the assay were constructed by integrating synthetic green fluorescent protein (sGFP) and Discosoma sp. red fluorescent protein (DsRedExp) genes into the genomes of C. gloeosporioides or C. capsici respectively. Survival of co-spore cultures in the presence of inhibitors was determined by the expression levels of these fluorescent proteins. This developed assay has high potential for utilization in the investigation of selective inhibition activity to either one of the pathogens as well as the broad-range inhibitory effect against both pathogens. The value of using the dual-fluorescent assay is rapid, reliable, and consistent identification of anti-anthracnose agents. Most of all, the assay enables the identification of specific inhibitors under the co-cultivation condition.

In vitro evaluation of fluorescence glucose biosensor response.

Science.gov (United States)

Aloraefy, Mamdouh; Pfefer, T Joshua; Ramella-Roman, Jessica C; Sapsford, Kim E

2014-07-08

Rapid, accurate, and minimally-invasive glucose biosensors based on Förster Resonance Energy Transfer (FRET) for glucose measurement have the potential to enhance diabetes control. However, a standard set of in vitro approaches for evaluating optical glucose biosensor response under controlled conditions would facilitate technological innovation and clinical translation. Towards this end, we have identified key characteristics and response test methods, fabricated FRET-based glucose biosensors, and characterized biosensor performance using these test methods. The biosensors were based on competitive binding between dextran and glucose to concanavalin A and incorporated long-wavelength fluorescence dye pairs. Testing characteristics included spectral response, linearity, sensitivity, limit of detection, kinetic response, reversibility, stability, precision, and accuracy. The biosensor demonstrated a fluorescence change of 45% in the presence of 400 mg/dL glucose, a mean absolute relative difference of less than 11%, a limit of detection of 25 mg/dL, a response time of 15 min, and a decay in fluorescence intensity of 72% over 30 days. The battery of tests presented here for objective, quantitative in vitro evaluation of FRET glucose biosensors performance have the potential to form the basis of future consensus standards. By implementing these test methods for a long-visible-wavelength biosensor, we were able to demonstrate strengths and weaknesses with a new level of thoroughness and rigor.

In Vitro Evaluation of Fluorescence Glucose Biosensor Response

Directory of Open Access Journals (Sweden)

Mamdouh Aloraefy

2014-07-01

Full Text Available Rapid, accurate, and minimally-invasive glucose biosensors based on Förster Resonance Energy Transfer (FRET for glucose measurement have the potential to enhance diabetes control. However, a standard set of in vitro approaches for evaluating optical glucose biosensor response under controlled conditions would facilitate technological innovation and clinical translation. Towards this end, we have identified key characteristics and response test methods, fabricated FRET-based glucose biosensors, and characterized biosensor performance using these test methods. The biosensors were based on competitive binding between dextran and glucose to concanavalin A and incorporated long-wavelength fluorescence dye pairs. Testing characteristics included spectral response, linearity, sensitivity, limit of detection, kinetic response, reversibility, stability, precision, and accuracy. The biosensor demonstrated a fluorescence change of 45% in the presence of 400 mg/dL glucose, a mean absolute relative difference of less than 11%, a limit of detection of 25 mg/dL, a response time of 15 min, and a decay in fluorescence intensity of 72% over 30 days. The battery of tests presented here for objective, quantitative in vitro evaluation of FRET glucose biosensors performance have the potential to form the basis of future consensus standards. By implementing these test methods for a long-visible-wavelength biosensor, we were able to demonstrate strengths and weaknesses with a new level of thoroughness and rigor.

Game Maturity Model for Health Care.

Science.gov (United States)

de Boer, Jan C; Adriani, Paul; van Houwelingen, Jan Willem; Geerts, A

2016-04-01

This article introduces the Game Maturity Model for the healthcare industry as an extension to the general Game Maturity Model and describes the usage by two case studies of applied health games. The Game Maturity Model for healthcare provides a practical and value-adding method to assess existing games and to determine strategic considerations for application of applied health games. Our forecast is that within 5 years the use and development of applied games will have a role in our daily lives and the way we organize health care that will be similar to the role social media has today.

Fluorescent optical position sensor

Science.gov (United States)

Weiss, Jonathan D.

2005-11-15

A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.

Introducing inducible fluorescent split cholesterol oxidase to mammalian cells.

Science.gov (United States)

Chernov, Konstantin G; Neuvonen, Maarit; Brock, Ivonne; Ikonen, Elina; Verkhusha, Vladislav V

2017-05-26

Cholesterol oxidase (COase) is a bacterial enzyme catalyzing the first step in the biodegradation of cholesterol. COase is an important biotechnological tool for clinical diagnostics and production of steroid drugs and insecticides. It is also used for tracking intracellular cholesterol; however, its utility is limited by the lack of an efficient temporal control of its activity. To overcome this we have developed a regulatable fragment complementation system for COase cloned from Chromobacterium sp. The enzyme was split into two moieties that were fused to FKBP (FK506-binding protein) and FRB (rapamycin-binding domain) pair and split GFP fragments. The addition of rapamycin reconstituted a fluorescent enzyme, termed split GFP-COase, the fluorescence level of which correlated with its oxidation activity. A rapid decrease of cellular cholesterol induced by intracellular expression of the split GFP-COase promoted the dissociation of a cholesterol biosensor D4H from the plasma membrane. The process was reversible as upon rapamycin removal, the split GFP-COase fluorescence was lost, and cellular cholesterol levels returned to normal. These data demonstrate that the split GFP-COase provides a novel tool to manipulate cholesterol in mammalian cells. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Total Internal Reflection Fluorescence Microscopy Imaging-Guided Confocal Single-Molecule Fluorescence Spectroscopy

OpenAIRE

Zheng, Desheng; Kaldaras, Leonora; Lu, H. Peter

2013-01-01

We have developed an integrated spectroscopy system combining total internal reflection fluorescence microscopy imaging with confocal single-molecule fluorescence spectroscopy for two-dimensional interfaces. This spectroscopy approach is capable of both multiple molecules simultaneously sampling and in situ confocal fluorescence dynamics analyses of individual molecules of interest. We have demonstrated the calibration with fluorescent microspheres, and carried out single-molecule spectroscop...

Concentrations of Nicotinamide in Plasma by RP-HPLC With Fluorescence Detection

Directory of Open Access Journals (Sweden)

Pan Zhipeng

2016-01-01

Full Text Available The purpose of this study is to establish a new method for detecting nicotinamide concentration in plasma. In the experiment, the high performance liquid chromatography (HPLC method was used, with a fluorescence detector. The nicotinamide in the plasma was first converted to N1- methylnicotinamide, then reacted with acetophenone under certain conditions to produce fluorescent derivatives for testing. The method is a kind of highly sensitive detection, of which the lower limit is 10 ng/mL, the recovery rate is between 92.75% and 105.13%, and the relative standard deviation (RSD is between 3.76% and 4.43%. The results showed that this measurement method is accurate, sensitive and rapid. It meets the requirements of the experiment, and applies to the detection of nicotinamide concentration in plasma.

Light-sheet fluorescence imaging to localize cardiac lineage and protein distribution

Science.gov (United States)

Ding, Yichen; Lee, Juhyun; Ma, Jianguo; Sung, Kevin; Yokota, Tomohiro; Singh, Neha; Dooraghi, Mojdeh; Abiri, Parinaz; Wang, Yibin; Kulkarni, Rajan P.; Nakano, Atsushi; Nguyen, Thao P.; Fei, Peng; Hsiai, Tzung K.

2017-02-01

Light-sheet fluorescence microscopy (LSFM) serves to advance developmental research and regenerative medicine. Coupled with the paralleled advances in fluorescence-friendly tissue clearing technique, our cardiac LSFM enables dual-sided illumination to rapidly uncover the architecture of murine hearts over 10 by 10 by 10 mm3 in volume; thereby allowing for localizing progenitor differentiation to the cardiomyocyte lineage and AAV9-mediated expression of exogenous transmembrane potassium channels with high contrast and resolution. Without the steps of stitching image columns, pivoting the light-sheet and sectioning the heart mechanically, we establish a holistic strategy for 3-dimentional reconstruction of the “digital murine heart” to assess aberrant cardiac structures as well as the spatial distribution of the cardiac lineages in neonates and ion-channels in adults.

Scanning fluorescent microscopy is an alternative for quantitative fluorescent cell analysis.

Science.gov (United States)

Varga, Viktor Sebestyén; Bocsi, József; Sipos, Ferenc; Csendes, Gábor; Tulassay, Zsolt; Molnár, Béla

2004-07-01

Fluorescent measurements on cells are performed today with FCM and laser scanning cytometry. The scientific community dealing with quantitative cell analysis would benefit from the development of a new digital multichannel and virtual microscopy based scanning fluorescent microscopy technology and from its evaluation on routine standardized fluorescent beads and clinical specimens. We applied a commercial motorized fluorescent microscope system. The scanning was done at 20 x (0.5 NA) magnification, on three channels (Rhodamine, FITC, Hoechst). The SFM (scanning fluorescent microscopy) software included the following features: scanning area, exposure time, and channel definition, autofocused scanning, densitometric and morphometric cellular feature determination, gating on scatterplots and frequency histograms, and preparation of galleries of the gated cells. For the calibration and standardization Immuno-Brite beads were used. With application of shading compensation, the CV of fluorescence of the beads decreased from 24.3% to 3.9%. Standard JPEG image compression until 1:150 resulted in no significant change. The change of focus influenced the CV significantly only after +/-5 microm error. SFM is a valuable method for the evaluation of fluorescently labeled cells. Copyright 2004 Wiley-Liss, Inc.

Simulating fluorescence light-canopy interaction in support of laser-induced fluorescence measurements

International Nuclear Information System (INIS)

Rosema, A.; Verhoef, W.; Schroote, J.; Snel, J.F.H.

1991-01-01

In the Netherlands an operational field instrument for the measurement of laser induced fluorescence of vegetation (LEAF) is developed. In addition, plant physiological and remote sensing research is done to support this new remote sensing instrument. This paper presents a general introduction on the subject of laser-induced fluorescence, including the relation between chlorophyll fluorescence and photosynthesis, spectral characteristics, and previous research. Also the LEAF system is briefly described. Subsequently, the development of a leaf fluorescence model (KMF) and a canopy fluorescence model (FLSAIL) are reported. With these simulation models a sensitivity study is carried out. Fluorescence of 685 nm appears to be most suitable to obtain information on photosynthesis and stress, but is also influenced by canopy structure. Separation of these two effects is studied

Quantitative liquid and vapor distribution measurements in evaporating fuel sprays using laser-induced exciplex fluorescence

International Nuclear Information System (INIS)

Fansler, Todd D; Drake, Michael C; Gajdeczko, Boguslaw; Düwel, Isabell; Koban, Wieland; Zimmermann, Frank P; Schulz, Christof

2009-01-01

Fully quantitative two-dimensional measurements of liquid- and vapor-phase fuel distributions (mass per unit volume) from high-pressure direct-injection gasoline injectors are reported for conditions of both slow and rapid vaporization in a heated, high-pressure spray chamber. The measurements employ the coevaporative gasoline-like fluorobenzene (FB)/diethylmethylamine (DEMA)/hexane exciplex tracer/fuel system. In contrast to most previous laser-induced exciplex-fluorescence (LIEF) experiments, the quantitative results here include regions in which liquid and vapor fuel coexist (e.g. near the injector exit). A unique aspect is evaluation of both vapor- and liquid-phase distributions at varying temperature and pressure using only in situ vapor-phase fluorescence calibration measurements at room temperature and atmospheric pressure. This approach draws on recent extensive measurements of the temperature-dependent spectroscopic properties of the FB–DEMA exciplex system, in particular on knowledge of the quantum efficiencies of the vapor-phase and liquid-phase (exciplex) fluorescence. In addition to procedures necessary for quantitative measurements, we discuss corrections for liquid–vapor crosstalk (liquid fluorescence that overlaps the vapor-fluorescence bandpass), the unknown local temperature due to vaporization-induced cooling, and laser-sheet attenuation by scattering and absorption

Probing Contaminant-Induced Alterations in Chlorophyll Fluorescence by AC-Dielectrophoresis-Based 2D-Algal Array

Directory of Open Access Journals (Sweden)

Coralie Siebman

2018-02-01

Full Text Available The investigation of contaminant impact on algae requires rapid and reliable cell collection and optical detection. The capability of alternative current (AC dielectrophoresis (DEP collection of whole cell arrays with combined fluorescence microscopy detection to follow the alterations of chlorophyll fluorescence during environmental contaminant exposure was explored. The application of an AC-field of 100 V cm−1, 100 Hz for 30 min to capture and immobilize the cells of green alga Chlamydomonas reinhardtii in two-dimensional (2D arrays does not induce changes in chlorophyll fluorescence. The results demonstrate that DEP-based 2D-arrays allow non-invasive detection of chlorophyll fluorescence change upon exposure to high concentrations of copper oxide nanoparticles and ionic copper. These results were in agreement with data obtained by flow cytometry used as a comparative method. The tool was also applied to follow the effect of a number of ubiquitous contaminants such as inorganic mercury, methylmercury, and diuron. However, a statistically significant short-term effect was observed only for mercury. Overall, DEP-based 2D-arrays of algal cells with fluorescence detection appear to be suitable for stain-free probing the effects on the photosynthetic microorganisms in highly polluted environment.

Advanced in X-ray fluorescence holography

CERN Document Server

Hayashi, K

2002-01-01

X-ray fluorescence holography (XFH) can resolve 'phase problem' in crystal diffraction and therefore it provides 3D atomic images around specific elements. Since first demonstration of the XFH in 1996, view of atoms has been improved rapidly with the refinement of the hologram data collection method. The present performance of the XFH makes it possible to apply to impurity, thin film and quasicrystal, and opens a way to practical tool for determination of local structure. In this paper, theory including solutions for twin image problem, advanced experimental systems and application to Si sub 0 sub . sub 9 sub 9 sub 9 Ge sub 0 sub . sub 0 sub 0 sub 1 are discussed. (author)

Extraction, separation, and detections of 14C-diazepam and 14C-metabolites from brain tissue of mature and old rats

International Nuclear Information System (INIS)

Komiskey, H.L.; Rahman, A.; Weisenburger, W.P.; Hayton, W.L.; Zobrist, R.H.; Silvius, W.

1985-01-01

A rapid method for simultaneous determination of brain concentrations of diazepan and each of its three major metabolites in brain tissue by a reverse isotope dilution procedure is presented. Radiolabeled diazepam and metabolites were extracted from brain tissue of mature and senescent rats with ethyl ether. After the ether was evaporated the benzodiazepines were separated from the residue by passing the water soluble portion through C-18 bonded-phase extraction columns. High pressure liquid chromatography (HPLC) was used to separate the benzodiazepines from each other. Reverse isotope dilution analysis was used to quantify diazepam and its metabolites. The percent recovery of diazepam and its metabolites from the brain of mature or senescent rats did not vary significantly

Fluorescence confocal endomicroscopy in biological imaging

Science.gov (United States)

Delaney, Peter; Thomas, Steven; Allen, John; McLaren, Wendy; Murr, Elise; Harris, Martin

2007-02-01

resolution. In rodent disease models, in vivo endomicroscopy with appropriate fluorescent agents allowed examination of thrombosis formation, tumour microvasculature and liver metastases, diagnosis and staging of ulcerative colitis, liver necrosis and glomerulonephritis. Miniaturised confocal endomicroscopy allows rapid in vivo molecular and subsurface microscopy of normal and pathologic tissue at high resolution in small and large whole animal models. Fluorescein endomicroscopy has recently been introduced into the medical device market as a clinical imaging tool in GI endoscopy and is undergoing clinical evaluation in laparoscopic surgery. This medical usage is encouraging in-situ endomicroscopy as an important pre-clinical research tool to observe microscopic and molecular system biologic events in vivo in animal models for various human diseases.

A potential fluorescent probe: Maillard reaction product from glutathione and ascorbic acid for rapid and label-free dual detection of Hg(2+) and biothiols.

Science.gov (United States)

Dong, Jiang Xue; Song, Xiao Fang; Shi, Yan; Gao, Zhong Feng; Li, Bang Lin; Li, Nian Bing; Luo, Hong Qun

2016-07-15

Maillard reactions and their fluorescent products have drawn much attention in the fields of food and life science, however, the application of fluorescent products separated from the reaction as an indicator for detection of certain substances in sensor field has not been mentioned. In this article, we report on an easy-to-synthesize and water-soluble fluorescent probe separated from the typical Maillard reaction products of glutathione and ascorbic acid, with excellent stability and high quantum yield (18.2%). The further application of the probe has been explored for dual detection of Hg(2+) and biothiols including cysteine, homocysteine, and glutathione, which is based on Hg(2+)-induced fluorescence quenching of the Maillard reaction fluorescent products (MRFPs) and the fluorescence recovery as the introduction of biothiols. This sensing system exhibits a good selectivity and sensitivity, and the linear ranges for Hg(2+), cysteine, homocysteine, and glutathione are 0.05-12, 0.5-10, 0.3-20, and 0.3-20μM, respectively. The detection limits for Hg(2+), cysteine, homocysteine, and glutathione are 22, 47, 96, and 30nM at a signal-to-noise ratio of 3, respectively. Furthermore, the practical applications of this sensor for Hg(2+) and biothiols determination in water samples and human plasma sample have been demonstrated with satisfactory results. Copyright © 2016 Elsevier B.V. All rights reserved.

Cord blood-derived macrophage-lineage cells rapidly stimulate osteoblastic maturation in mesenchymal stem cells in a glycoprotein-130 dependent manner.

Directory of Open Access Journals (Sweden)

Tania J Fernandes

Full Text Available In bone, depletion of osteoclasts reduces bone formation in vivo, as does osteal macrophage depletion. How osteoclasts and macrophages promote the action of bone forming osteoblasts is, however, unclear. Since recruitment and differentiation of multi-potential stromal cells/mesenchymal stem cells (MSC generates new active osteoblasts, we investigated whether human osteoclasts and macrophages (generated from cord blood-derived hematopoietic progenitors induce osteoblastic maturation in adipose tissue-derived MSC. When treated with an osteogenic stimulus (ascorbate, dexamethasone and β-glycerophosphate these MSC form matrix-mineralising, alkaline phosphatase-expressing osteoblastic cells. Cord blood-derived progenitors were treated with macrophage colony stimulating factor (M-CSF to form immature proliferating macrophages, or with M-CSF plus receptor activator of NFκB ligand (RANKL to form osteoclasts; culture medium was conditioned for 3 days by these cells to study their production of osteoblastic factors. Both osteoclast- and macrophage-conditioned medium (CM greatly enhanced MSC osteoblastic differentiation in both the presence and absence of osteogenic medium, evident by increased alkaline phosphatase levels within 4 days and increased mineralisation within 14 days. These CM effects were completely ablated by antibodies blocking gp130 or oncostatin M (OSM, and OSM was detectable in both CM. Recombinant OSM very potently stimulated osteoblastic maturation of these MSC and enhanced bone morphogenetic protein-2 (BMP-2 actions on MSC. To determine the influence of macrophage activation on this OSM-dependent activity, CM was collected from macrophage populations treated with M-CSF plus IL-4 (to induce alternative activation or with GM-CSF, IFNγ and LPS to cause classical activation. CM from IL-4 treated macrophages stimulated osteoblastic maturation in MSC, while CM from classically-activated macrophages did not. Thus, macrophage-lineage cells

Production and testing of {sup 244}Cm-labeled fluorescent polystyrene latex microspheres

Energy Technology Data Exchange (ETDEWEB)

Guilmette, R A; Mueller, H L; Brodbeck, R D

1988-12-01

To provide a useful tool for studying the mechanisms of retention and translocation of respirable-sized, alpha-emitting particles, we have developed a method of incorporating {sup 244}Cm into fluorescent polystyrene latex microspheres. The resultant particles contain alpha radioactivity comparable to {mu}m-size (AMAD) {sup 239}Pu0{sub 2} particles, but are easily visible by fluorescent light microscopy. Preliminary testing of the particles with dog macrophages in vitro has shown that the initial uptake of these Cm-labeled particles is more rapid than uptake of unlabeled particles of similar size. We are continuing to develop procedures for achieving better particle yields, smaller dispersity of particle size distributions and improved retention of the Cm label by the particles. (author)

Vegetative propagation of mature and juvenile northern red oak

Science.gov (United States)

James J. Zaczek; K. C. Steiner; C. W., Jr. Heuser

1993-01-01

Rooting trials were established to evaluate rooting success of cuttings from mature and juvenile, grafted and ungrafted northern red oak (NRO). Buds from 4 mature NRO ortets and juvenile seedlings were grafted onto juvenile and mature rootstock. Cuttings were collected from the grafts and from juvenile and mature shoots developed in situ and...

Decision-Making Style and Vocational Maturity.

Science.gov (United States)

Phillips, Susan D.; Strohmer, Douglas C.

1982-01-01

Examined the relationship between decision-making style, scholastic achievement, and vocational maturity for college students (N=64). Results did not support the hypothesized relationship between rationality and attitudinal and cognitive maturity. Scholastic achievement and lack of dependent decision style were found to be moderately predictive of…

Color back projection for fruit maturity evaluation

Science.gov (United States)

Zhang, Dong; Lee, Dah-Jye; Desai, Alok

2013-12-01

In general, fruits and vegetables such as tomatoes and dates are harvested before they fully ripen. After harvesting, they continue to ripen and their color changes. Color is a good indicator of fruit maturity. For example, tomatoes change color from dark green to light green and then pink, light red, and dark red. Assessing tomato maturity helps maximize its shelf life. Color is used to determine the length of time the tomatoes can be transported. Medjool dates change color from green to yellow, and the orange, light red and dark red. Assessing date maturity helps determine the length of drying process to help ripen the dates. Color evaluation is an important step in the processing and inventory control of fruits and vegetables that directly affects profitability. This paper presents an efficient color back projection and image processing technique that is designed specifically for real-time maturity evaluation of fruits. This color processing method requires very simple training procedure to obtain the frequencies of colors that appear in each maturity stage. This color statistics is used to back project colors to predefined color indexes. Fruit maturity is then evaluated by analyzing the reprojected color indexes. This method has been implemented and used for commercial production.

Fluorescence molecular tomography in the presence of background fluorescence

International Nuclear Information System (INIS)

Soubret, Antoine; Ntziachristos, Vasilis

2006-01-01

Fluorescence molecular tomography is an emerging imaging technique that resolves the bio-distribution of engineered fluorescent probes developed for in vivo reporting of specific cellular and sub-cellular targets. The method can detect fluorochromes in picomole amounts or less, imaged through entire animals, but the detection sensitivity and imaging performance drop in the presence of background, non-specific fluorescence. In this study, we carried out a theoretical and an experimental investigation on the effect of background fluorescence on the measured signal and on the tomographic reconstruction. We further examined the performance of three subtraction methods based on physical models of photon propagation, using experimental data on phantoms and small animals. We show that the data pre-processing with subtraction schemes can improve image quality and quantification when non-specific background florescence is present

Submicron polymer particles containing fluorescent semiconductor nanocrystals CdSe/ZnS for bioassays.

Science.gov (United States)

Generalova, Alla N; Sizova, Svetlana V; Zdobnova, Tatiana A; Zarifullina, Margarita M; Artemyev, Michail V; Baranov, Alexander V; Oleinikov, Vladimir A; Zubov, Vitaly P; Deyev, Sergey M

2011-02-01

This study aimed to design a panel of uniform particulate biochemical reagents and to test them in specific bioassays. These reagents are polymer particles of different sizes doped with semiconductor nanocrystals and conjugated with either full-size antibodies or recombinant mini-antibodies (4D5 scFv fragment) designed by genetic engineering approaches. A panel of highly fluorescent polymer particles (150-800 nm) were formed by embedding CdSe/ZnS nanocrystals (quantum dots) into preformed polyacrolein and poly(acrolein-co-styrene) particles. Morphology, content and fluorescence characteristics of the prepared materials were studied by laser correlation spectroscopy, spectrophotometry, optical and fluorescent microscopy and fluorimetry. The obtained fluorescent particles sensitized by anti-Yersinia pestis antibodies were used for rapid agglutination glass test suitable for screening analysis of Y. pestis antigen and for microtiter particle agglutination, which, owing to its speed and simplicity, is very beneficial for diagnostic detection of Y. pestis antigen. Recombinant 4D5 scFv antibodies designed and conjugated with polymer particles containing quantum dots provide multipoint highly specific binding with cancer marker HER2/neu on the surface of SKOV-3 cell.

X-ray fluorescence analysis of metal concentration in an alloy electroplating bath

International Nuclear Information System (INIS)

Hines, R.A.

1980-06-01

An energy-dispersive x-ray fluorescence analysis system has been developed for rapid, simultaneous analysis of gold and copper concentrations in an aqueous electroplating bath. The speed and repeatability of the system make it well suited for in-process control. Data collection and reduction are automatic. The analysis requires less than 10 minutes from taking the sample to printing the gold and copper concentrations

Long Maturity Forward Rates

DEFF Research Database (Denmark)

Christiansen, Charlotte

2001-01-01

The paper aims to improve the knowledge of the empirical properties of the long maturity region of the forward rate curve. Firstly, the theoretical negative correlation between the slope at the long end of the forward rate curve and the term structure variance is recovered empirically and found...... to be statistically significant. Secondly, the expectations hypothesis is analyzed for the long maturity region of the forward rate curve using "forward rate" regressions. The expectations hypothesis is numerically close to being accepted but is statistically rejected. The findings provide mixed support...... for the affine term structure model....

Determination of trace aluminum by fluorescence quenching method based on catalysis of potassium chlorate oxidizing alizarin red

Science.gov (United States)

Shao-Qin, Lin; Xuan, Lin; Shi-Rong, Hu; Li-Qing, Zeng; Yan, Wang; Li, Chen; Jia-Ming, Liu; Long-Di, Li

2005-11-01

A new method for the determination of trace aluminum has been proposed. It is based on the fact that alizarin red can emit strong and stable fluorescence at 80 °C for 30 min and Al 3+ can effectively catalyze potassium chlorate oxidizing alizarin red to form non-fluorescence complex which cause the fluorescence quenching. The linear dynamic range of this method is 0.040-4.00 ng l -1 with a detection limit of 5.3 pg l -1. The regression equation can be expressed as Δ If = 8.731 + 21.73 c (ng l -1), with the correlation coefficient r = 0.9992 ( n = 6). This sensitive, rapid and accurate method has been applied to the determination of trace aluminum(III) in human hair and tea samples successfully. What is more, the mechanism of catalyzing potassium chlorate oxidizing alizarin red by the fluorescence quenching method is also discussed.

Moving Toward Quantifying Reliability - The Next Step in a Rapidly Maturing PV Industry: Preprint

Energy Technology Data Exchange (ETDEWEB)