Photomultiplier tube gain regulating system

DOEpatents

Johnson, Wayne F.

1976-01-01

This invention relates to an improved system for regulating the gain of a photomultiplier tube, and was designed for use with the photomultiplier tubes of a GeMSAEC fast analyzers. It has the following advantages over the prior system: noise is virtually eliminated; sample analysis can begin after 3 to 4 revolutions of the rotor; fluorescent and light scattering solutions can be used as a reference; and the reference solution can be in any cuvette on the rotor.

Side illuminated optical fiber as a multiplexing element for spectroscopic systems

NASA Astrophysics Data System (ADS)

Egalon, Claudio O.; Matta, Michael P.; Lavezzari, Delbert C.; Insley, Robert Y.; Jaring, Carolyn C.; Quiday, Marie F.

2013-09-01

A new type of colorimeter with multiple channels was demonstrated using a side illuminated optical fiber. When different spots of a properly modified fiber are side illuminated, multiple signals are generated and guided by the waveguide: the essence of multiplexing. This configuration is simple, low cost, does not require a sensitive coating and can analyze several samples along the fiber with a single detector: the most expensive component. Since regular colorimeters use one detector per sample, our new configuration considerably lowers the cost of analyzing multiple samples. This system consists of a fiber mounted over a support, three LEDs, an LED driver, a photo diode and a read-out: to increase the signal, the fiber was tapered. For calibration purposes, six solutions of different concentrations of food dye were prepared, placed inside cuvettes along the fiber length and illuminated by the LEDs. This light passes through the solution, strikes the fiber and is guided to the detector: the darker the solution the lower the signal intensity. Several calibration curves were obtained using different light intensities: it was found that the greater the intensity, the higher the colorimeter sensitivity. This simple capability can be used to easily control the device's sensitivity and its resolution. Although built for three samples only, this device can be modified to accommodate more. With cuvettes measuring 1 cm, it is possible to accommodate one sample per cm of fiber. Also, with minor modifications, this colorimeter can be used for fluorescence, scattering and index of refraction measurements.

Low-temperature kinetic measurements of microsecond freeze-hyperquench (MHQ) cytochrome oxidase monitored by UV-visible spectroscopy with a newly designed cuvette.

PubMed

Wiertz, F G M; de Vries, S

2006-02-01

A special cuvette was designed to measure optical changes of MHQ (microsecond freeze-hyperquench) powder samples at temperatures below approx. 250 K. Reduced cytochrome c oxidase from Paracoccus denitrificans was reacted with O(2) for 100 micros, frozen as a powder and transferred to the cuvette. Subsequently, cytochrome oxidase was allowed to react further following stepwise increments of the temperature from 100 K up to 250 K while recording spectra between 300 and 700 nm. The temperature was raised only when no further changes in the spectra could be detected. The experiment yielded spectra of the A, P(M), F and O intermediate states. This demonstrated that the catalytic cycle of cytochrome oxidase at low temperature is similar to that at room temperature and so verifies the suitability of this method for the study of enzymes with high catalytic-centre activity.

Neutron scattering investigation of a macroscopic single crystal of a lyotropic Lα phase

NASA Astrophysics Data System (ADS)

Goecking, K. D.; Monkenbusch, M.

1998-07-01

Water-rich lamellar samples of the quaternary microemulsion SDS-pentanol-water-dodecane have been prepared in form of 1 mm×10 mm×20 mm macroscopic mono domains. The shape is given by the quartz cuvette containing the sample, the layer planes are parallel to the cuvette walls. Diffraction patterns and "rocking curves" have been obtained by neutron diffraction using a triple-axis spectrometer. Three "pseudo-Bragg peaks" have been observed, their (relative) intensities yield a new experimental access to estimate the product of the elastic constants η-2 propto Bκ resulting in a lower value than obtained from synchrotron investigation using peak shape fitting (Roux D. et al., Micelles, Membranes, Microemulsions and Monolayers (Springer, New York, Berlin) 1994).

The influence of water vapor on atmospheric exchange measurements with an ICOS* based Laser absorption analyzer

NASA Astrophysics Data System (ADS)

Bunk, Rüdiger; Quan, Zhi; Wandel, Matthias; Yi, Zhigang; Bozem, Heiko; Kesselmeier, Jürgen

2014-05-01

Carbonyl sulfide and carbon monoxide are both atmospheric trace gases of high interest. Recent advances in the field of spectroscopy have enabled instruments that measure the concentration of the above and other trace gases very fast and with good precision. Increasing the effective path length by reflecting the light between two mirrors in a cavity, these instruments reach impressive sensitivities. Often it is possible to measure the concentration of more than one trace gas at the same time. The OCS/CO2 Analyzer by LGR (Los Gatos Research, Inc.) measures the concentration of water vapor [H2O], carbonyl sulfide [COS], carbon dioxide [CO2] and carbon monoxide [CO] simultaneously. For that the cavity is saturated with light, than the attenuation of light is measured as in standard absorption spectroscopy. The instrument proved to be very fast with good precision and to be able to detect even very low concentrations, especially for COS (as low as 30ppt in the case of COS). However, we observed a rather strong cross sensitivity to water vapor. Altering the water vapor content of the sampled air with two different methods led to a change in the perceived concentration of COS, CO and CO2. This proved especially problematic for enclosure (cuvette) measurements, where the concentrations of one of the above species in an empty cuvette are compared to the concentration of another cuvette containing a plant whose exchange of trace gases with the atmosphere is of interest. There, the plants transpiration leads to a large difference in water vapor content between the cuvettes and that in turn produces artifacts in the concentration differences between the cuvettes for the other above mentioned trace gases. For CO, simultaneous measurement with a UV-Emission Analyzer (AL 5002, Aerolaser) and the COS/CO Analyzer showed good agreement of perceived concentrations as long as the sample gas was dry and an increasing difference in perceived concentration when the sample gas was humidified. The difference in perceived CO concentration showed a clear correlation to the water vapor content in the sample air. For COS we could show that changes in water vapor also impacted on the perceived COS concentrations; the raise of the water vapor concentration would lead to an increasing underestimation of the COS concentration. Drying the air using a Nafion Dryer before entering the COS/CO Analyzer eliminated any water vapor induced artifacts and showed no adverse effects on the quality of the conducted measurements. *Integrated cavity output spectroscopy

Technical brief: Pump-probe paradigm in an integrating cavity to study photodecomposition processes

PubMed Central

Betts-Obregon, Brandi; Tsin, Andrew T.; DeSa, Richard J.

2016-01-01

Purpose Assaying photodecomposition is challenging because light must be used to initiate the photodamage and light must be used to monitor the photodecomposition. The experimental requirements are as follows: 1) During exposure of the actinic beam, continuously monitor the spectral characteristics of the sample, 2) uniformly expose the reactants to the actinic source, 3) obtain informative spectra in the presence of light scatter, and 4) achieve sufficient sensitivity for dilute reactants. Traditional spectrophotometers cannot address these issues due to sample turbidity, the inability to uniformly expose the cuvette contents to the incident beam, the inability to simultaneously perform spectral scans, and inherent low sensitivity. Here, we describe a system that meets these challenges in a practical way. Methods Light access to a 8.6 ml quartz integrating sphere containing 10 µM all-trans retinol in PBS was provided by three ports at right angles allowing for the following: 1) actinic light delivery from light-emitting diodes (LEDs) firing at 100 pulses/sec, 2) entry of a separate scanning beam at 100 scans/sec (10,000 µsec scan time) via an OLIS RSM 1000 ultraviolet/visual (UV/Vis) rapid-scanning spectrophotometer (RSM), and 3) light exit to the detector photomultiplier. The RSM spectral intermediate slit was partially covered to allow for a “dark” period of 2,000 µsec when no scanning light was admitted to the cuvette. During that interval, the LED was flashed, and the photomultiplier was temporarily blocked by a perforated spinning shutter disk. The absorbance per centimeter, which is increased due to the internal reflectance of the integrating sphere compared to a standard 1 cm rectangular cuvette, was calculated according to Fry et al. (2010) Applied Optics 49:575. Retinoid photodecomposition was confirmed with high-performance liquid chromatography (HPLC). Results Using the RSM to trigger the LED flash and photomultiplier shutter closure during the “dark” period allowed actinic flashes to be placed between scans. Exposure of the all-trans retinol to 366 nm flashes resulted in marked reduction in absorbance and a blue shift of the λmax. A white LED, despite its higher photon output, did not support all-trans retinol photolysis. Singular value decomposition (SVD) analysis revealed three spectral intermediates with mechanism, I -> II -> III. HPLC analysis of the reactants at the beginning and the conclusion of the light exposure confirmed the retinol photodecomposition. Conclusions The highly reflecting cavity acts as a multipass cuvette that markedly increased the light path length and, thus, sensitivity. Triggering the LED during a dark period within the scan time allowed the actinic flashes to be interleafed between scans in a pump-probe paradigm. Furthermore, the entire sample was exposed to scan beam and actinic flashes, which is not possible in traditional spectrophotometers. Finally, the integrating cavity cuvette allowed use of turbid samples. SVD was useful for resolving spectral intermediates. Although the identity of the intermediates was not determined here, the ability to define molecular intermediates during photodecomposition reactions will allow future studies to isolate and identify the degradation products and determine the mechanism of light-induced retinoid degradation and that of retinoid-binding protein-mediated photoprotection. PMID:27559291

Avoiding the side effects of electric current pulse application to electroporated cells in disposable small volume cuvettes assures good cell survival.

PubMed

Grys, Maciej; Madeja, Zbigniew; Korohoda, Włodzimierz

2017-01-01

The harmful side effects of electroporation to cells due to local changes in pH, the appearance of toxic electrode products, temperature increase, and the heterogeneity of the electric field acting on cells in the cuvettes used for electroporation were observed and discussed in several laboratories. If cells are subjected to weak electric fields for prolonged periods, for example in experiments on cell electrophoresis or galvanotaxis the same effects are seen. In these experiments investigators managed to reduce or eliminate the harmful side effects of electric current application. For the experiments, disposable 20 μl cuvettes with two walls made of dialysis membranes were constructed and placed in a locally focused electric field at a considerable distance from the electrodes. Cuvettes were mounted into an apparatus for horizontal electrophoresis and the cells were subjected to direct current electric field (dcEF) pulses from a commercial pulse generator of exponentially declining pulses and from a custom-made generator of double and single rectangular pulses. More than 80% of the electroporated cells survived the dcEF pulses in both systems. Side effects related to electrodes were eliminated in both the flow through the dcEF and in the disposable cuvettes placed in the focused dcEFs. With a disposable cuvette system, we also confirmed the sensitization of cells to a dcEF using procaine by observing the loading of AT2 cells with calceine and using a square pulse generator, applying 50 ms single rectangular pulses. We suggest that the same methods of avoiding the side effects of electric current pulse application as in cell electrophoresis and galvanotaxis should also be used for electroporation. This conclusion was confirmed in our electroporation experiments performed in conditions assuring survival of over 80% of the electroporated cells. If the amplitude, duration, and shape of the dcEF pulse are known, then electroporation does not depend on the type of pulse generator. This knowledge of the characteristics of the pulse assures reproducibility of electroporation experiments using different equipment.

Sample handling in surface sensitive chemical and biological sensing: a practical review of basic fluidics and analyte transport.

PubMed

Orgovan, Norbert; Patko, Daniel; Hos, Csaba; Kurunczi, Sándor; Szabó, Bálint; Ramsden, Jeremy J; Horvath, Robert

2014-09-01

This paper gives an overview of the advantages and associated caveats of the most common sample handling methods in surface-sensitive chemical and biological sensing. We summarize the basic theoretical and practical considerations one faces when designing and assembling the fluidic part of the sensor devices. The influence of analyte size, the use of closed and flow-through cuvettes, the importance of flow rate, tubing length and diameter, bubble traps, pressure-driven pumping, cuvette dead volumes, and sample injection systems are all discussed. Typical application areas of particular arrangements are also highlighted, such as the monitoring of cellular adhesion, biomolecule adsorption-desorption and ligand-receptor affinity binding. Our work is a practical review in the sense that for every sample handling arrangement considered we present our own experimental data and critically review our experience with the given arrangement. In the experimental part we focus on sample handling in optical waveguide lightmode spectroscopy (OWLS) measurements, but the present study is equally applicable for other biosensing technologies in which an analyte in solution is captured at a surface and its presence is monitored. Explicit attention is given to features that are expected to play an increasingly decisive role in determining the reliability of (bio)chemical sensing measurements, such as analyte transport to the sensor surface; the distorting influence of dead volumes in the fluidic system; and the appropriate sample handling of cell suspensions (e.g. their quasi-simultaneous deposition). At the appropriate places, biological aspects closely related to fluidics (e.g. cellular mechanotransduction, competitive adsorption, blood flow in veins) are also discussed, particularly with regard to their models used in biosensing. Copyright © 2014 Elsevier B.V. All rights reserved.

Development of a portable NanoAptamer analyzer for the detection of bisphenol A

NASA Astrophysics Data System (ADS)

Son, Ahjeong; Lim, Hyun Jeong; Chua, Beelee

2017-04-01

We have demonstrated a portable NanoAptamer analyzer capable of detecting bisphenol A (BPA) at environmentally relevant concentrations (< 1 ng/mL or ppb). It is designed for performing reaction and fluorescence measurement on single cuvette sample. NanoAptamer assay was developed and used as a sensing mechanism where signaling DNA and QD655 was tethered to QD565 and magnetic bead via the aptamer. Aptamer affinity with BPA resulted in the release of the signaling DNA and QD655 from the complex and hence corresponding decrease in QD655 fluorescence measurement signal. Baseline characterization was first performed with empty cuvettes, quantum dots and magnetic beads under near-ideal conditions to establish essential functionality of the NanoAptamer analyzer. Duration of incubation time, number of rinse cycles, and necessity of cuvette vibration were also investigated. In order to demonstrate the capability of the NanoAptamer analyzer to detect BPA, samples with BPA concentrations ranging from 0.0005 to 1.0 ng/mL (ppb) were used. The performance of the NanoAptamer analyzer was further examined by using laboratory protocol and commercial spectrofluorometer as reference. Correlation between NanoAptamer analyzer and laboratory protocol as well as commercial spectrofluorometer was evaluated via correlation plots and correlation coefficients.

Detection of bisphenol A using palm-size NanoAptamer analyzer.

PubMed

Lim, Hyun Jeong; Chua, Beelee; Son, Ahjeong

2017-08-15

We have demonstrated a palm-size NanoAptamer analyzer capable of detecting bisphenol A (BPA) at environmentally relevant concentrations (<1ng/mL or ppb). It is designed for performing reaction and fluorescence measurement on single cuvette sample. Modified NanoGene assay was used as the sensing mechanism where signaling DNA and QD 655 was tethered to QD 565 and magnetic bead via the aptamer. Aptamer affinity with BPA resulted in the release of the signaling DNA and QD 655 from the complex and hence corresponding decrease in QD 655 fluorescence measurement signal. Baseline characterization was first performed with empty cuvettes, quantum dots and magnetic beads under near-ideal conditions to establish essential functionality of the NanoAptamer analyzer. Duration of incubation time, number of rinse cycles, and necessity of cuvette vibration were also investigated. In order to demonstrate the capability of the NanoAptamer analyzer to detect BPA, samples with BPA concentrations ranging from 0.0005 to 1.0ng/mL (ppb) were used. The performance of the NanoAptamer analyzer was further examined by using laboratory protocol and commercial spectrofluorometer as reference. Correlation between NanoAptamer analyzer and laboratory protocol as well as commercial spectrofluorometer was evaluated via correlation plots and correlation coefficients. Copyright © 2017 Elsevier B.V. All rights reserved.

[Analysis of antibiotic diffusion from agarose gel by spectrophotometry and laser interferometry methods].

PubMed

Arabski, Michał; Wasik, Sławomir; Piskulak, Patrycja; Góźdź, Natalia; Slezak, Andrzej; Kaca, Wiesław

2011-01-01

The aim of this study was to analysis of antibiotics (ampicilin, streptomycin, ciprofloxacin or colistin) release from agarose gel by spectrophotmetry and laser interferometry methods. The interferometric system consisted of a Mach-Zehnder interferometer with a He-Ne laser, TV-CCD camera, computerised data acquisition system and a gel system. The gel system under study consists of two cuvettes. We filled the lower cuvette with an aqueous 1% agarose solution with the antibiotics at initial concentration of antibiotics in the range of 0.12-2 mg/ml for spectrophotmetry analysis or 0.05-0.5 mg/ml for laser interferometry methods, while in the upper cuvette there was pure water. The diffusion was analysed from 120 to 2400 s with a time interval of deltat = 120 s by both methods. We observed that 0.25-1 mg/ml and 0,05 mg/ml are minimal initial concentrations detected by spectrophotometric and laser interferometry methods, respectively. Additionally, we observed differences in kinetic of antibiotic diffusion from gel measured by both methods. In conclusion, the laser interferometric method is a useful tool for studies of antibiotic release from agarose gel, especially for substances are not fully soluble in water, for example: colistin.

Electrochemical apparatus comprising modified disposable rectangular cuvette

DOEpatents

Dattelbaum, Andrew M; Gupta, Gautam; Morris, David E

2013-09-10

Electrochemical apparatus includes a disposable rectangular cuvette modified with at least one hole through a side and/or the bottom. Apparatus may include more than one cuvette, which in practice is a disposable rectangular glass or plastic cuvette modified by drilling the hole(s) through. The apparatus include two plates and some means of fastening one plate to the other. The apparatus may be interfaced with a fiber optic or microscope objective, and a spectrometer for spectroscopic studies. The apparatus are suitable for a variety of electrochemical experiments, including surface electrochemistry, bulk electrolysis, and flow cell experiments.

Mycological studies housed in the Apollo 16 microbial ecology evaluation device

NASA Technical Reports Server (NTRS)

Volz, P. A.

1973-01-01

Survival, death, and phenotype count have yielded variation in the number of fungi recovered from the controls and the flight exposed cuvettes during preliminary analysis of postflight first phase data. Also the preliminary analysis was indicative that fungi exposed to specific space flight conditions demonstrated variable survival rates and phenotype counts. Specific space flight conditions included full light space exposure for Chaetomium globosum, exposure at 300- and 254-nanometer wavelengths for Rhodotorula rubra, full light and 280-nanometer wavelength exposure for Trichophyton terrestre, and 254-nanometer wavelength exposure for Saccharomyces cerevisiae. In general, phenotype counts for flight cuvettes and survival rates for control cuvettes were higher compared with the remaining cuvettes.

A low volume 3D-printed temperature-controllable cuvette for UV visible spectroscopy.

PubMed

Pisaruka, Jelena; Dymond, Marcus K

2016-10-01

We report the fabrication of a 3D-printed water-heated cuvette that fits into a standard UV visible spectrophotometer. Full 3D-printable designs are provided and 3D-printing conditions have been optimised to provide options to print the cuvette in either acrylonitrile butadiene styrene or polylactic acid polymers, extending the range of solvents that are compatible with the design. We demonstrate the efficacy of the cuvette by determining the critical micelle concentration of sodium dodecyl sulphate at 40 °C, the molar extinction coefficients of cobalt nitrate and dsDNA and by reproducing the thermochromic UV visible spectrum of a mixture of cobalt chloride, water and propan-2-ol. Copyright © 2016 Elsevier Inc. All rights reserved.

Natural Inhibitors of Maillard Browning

DTIC Science & Technology

2013-12-01

1.2 FLAVONOIDS .....................................................................................................................2 1.3 GOAL AND... flavonoid backbone .................................................................. 2  Figure 2: Cuvettes containing the glucose:glycine model system... flavonoids added to the model system and stored for 10 weeks at 50 °C

Rapid and precise determination of ATP using a modified photometer

USGS Publications Warehouse

Shultz, David J.; Stephens, Doyle W.

1980-01-01

An inexpensive delay timer was designed to modify a commercially available ATP photometer which allows a disposable tip pipette to be used for injecting either enzyme or sample into the reaction cuvette. The disposable tip pipette is as precise and accurate as a fixed-needle syringe but eliminates the problem of sample contamination and decreases analytical time. (USGS)

Establishing the suitability of quantitative optical CT microscopy of PRESAGE® radiochromic dosimeters for the verification of synchrotron microbeam therapy

NASA Astrophysics Data System (ADS)

Doran, Simon J.; Rahman, A. T. Abdul; Bräuer-Krisch, Elke; Brochard, Thierry; Adamovics, John; Nisbet, Andrew; Bradley, David

2013-09-01

Previous research on optical computed tomography (CT) microscopy in the context of the synchrotron microbeam has shown the potential of the technique and demonstrated high quality images, but has left two questions unanswered: (i) are the images suitably quantitative for 3D dosimetry? and (ii) what is the impact on the spatial resolution of the system of the limited depth-of-field of the microscope optics? Cuvette and imaging studies are reported here that address these issues. Two sets of cuvettes containing the radiochromic plastic PRESAGE® were irradiated at the ID17 biomedical beamline of the European Synchrotron Radiation facility over the ranges 0-20 and 0-35 Gy and a third set of cuvettes was irradiated over the range 0-20 Gy using a standard medical linac. In parallel, three cylindrical PRESAGE® samples of diameter 9.7 mm were irradiated with test patterns that allowed the quantitative capabilities of the optical CT microscope to be verified, and independent measurements of the imaging modulation transfer function (MTF) to be made via two different methods. Both spectrophotometric analysis and imaging gave a linear dose response, with gradients ranging from 0.036-0.041 cm-1 Gy-1 in the three sets of cuvettes and 0.037 (optical CT units) Gy-1 for the imaging. High-quality, quantitative imaging results were obtained throughout the 3D volume, as illustrated by depth-dose profiles. These profiles are shown to be monoexponential, and the linear attention coefficient of PRESAGE® for the synchrotron-generated x-ray beam is measured to be (0.185 ± 0.02) cm-1 in excellent agreement with expectations. Low-level (<5%) residual image artefacts are discussed in detail. It was possible to resolve easily slit patterns of width 37 µm (which are smaller than many of the microbeams used on ID-17), but some uncertainty remains as to whether the low values of MTF for the higher spatial frequencies are scanner related or a result of genuine (but non-ideal) dose distributions. We conclude that microscopy images from our scanner do indeed have intensities that are proportional to spectrophotometric optical density and can thus be used as the basis for accurate dosimetry. However, further investigations are necessary before the microscopy images can be used to make the quantitative measures of peak-to-valley ratios for small-diameter microbeams. We suggest various strategies for moving forward and are optimistic about the future potential of this system.

Sample Handling and Chemical Kinetics in an Acoustically Levitated Drop Microreactor

PubMed Central

2009-01-01

Accurate measurement of enzyme kinetics is an essential part of understanding the mechanisms of biochemical reactions. The typical means of studying such systems use stirred cuvettes, stopped-flow apparatus, microfluidic systems, or other small sample containers. These methods may prove to be problematic if reactants or products adsorb to or react with the container’s surface. As an alternative approach, we have developed an acoustically-levitated drop reactor eventually intended to study enzyme-catalyzed reaction kinetics related to free radical and oxidative stress chemistry. Microliter-scale droplet generation, reactant introduction, maintenance, and fluid removal are all important aspects in conducting reactions in a levitated drop. A three capillary bundle system has been developed to address these needs. We report kinetic measurements for both luminol chemiluminescence and the reaction of pyruvate with nicotinamide adenine dinucleotide, catalyzed by lactate dehydrogenase, to demonstrate the feasibility of using a levitated drop in conjunction with the developed capillary sample handling system as a microreactor. PMID:19769373

Method and apparatus for automated processing and aliquoting of whole blood samples for analysis in a centrifugal fast analyzer

DOEpatents

Burtis, C.A.; Johnson, W.F.; Walker, W.A.

1985-08-05

A rotor and disc assembly for use in a centrifugal fast analyzer. The assembly is designed to process multiple samples of whole blood followed by aliquoting of the resultant serum into precisely measured samples for subsequent chemical analysis. The assembly requires minimal operator involvement with no mechanical pipetting. The system comprises: (1) a whole blood sample disc; (2) a serum sample disc; (3) a sample preparation rotor; and (4) an analytical rotor. The blood sample disc and serum sample disc are designed with a plurality of precision bore capillary tubes arranged in a spoked array. Samples of blood are loaded into the blood sample disc by capillary action and centrifugally discharged into cavities of the sample preparation rotor where separation of serum and solids is accomplished. The serum is loaded into the capillaries of the serum sample disc by capillary action and subsequently centrifugally expelled into cuvettes of the analyticaly rotor for conventional methods. 5 figs.

Method and apparatus for automated processing and aliquoting of whole blood samples for analysis in a centrifugal fast analyzer

DOEpatents

Burtis, Carl A.; Johnson, Wayne F.; Walker, William A.

1988-01-01

A rotor and disc assembly for use in a centrifugal fast analyzer. The assembly is designed to process multiple samples of whole blood followed by aliquoting of the resultant serum into precisely measured samples for subsequent chemical analysis. The assembly requires minimal operator involvement with no mechanical pipetting. The system comprises (1) a whole blood sample disc, (2) a serum sample disc, (3) a sample preparation rotor, and (4) an analytical rotor. The blood sample disc and serum sample disc are designed with a plurality of precision bore capillary tubes arranged in a spoked array. Samples of blood are loaded into the blood sample disc in capillary tubes filled by capillary action and centrifugally discharged into cavities of the sample preparation rotor where separation of serum and solids is accomplished. The serum is loaded into the capillaries of the serum sample disc by capillary action and subsequently centrifugally expelled into cuvettes of the analytical rotor for analysis by conventional methods.

A Continuous Flow System for the Measurement of Ambient Nitrogen Oxides [NO + NO2] Using Rhodamine B Hydrazide as a Chemosensor.

PubMed

Malingappa, Pandurangappa; Yarradoddappa, Venkataramanappa

2014-01-01

A new chemosensor has been used to monitor atmospheric nitrogen oxides [NO + NO2] at parts per billion (ppb) level. It is based on the catalytic reaction of nitrogen oxides with rhodamine B hydrazide (RBH) to produce a colored compound through the hydrolysis of the amide bond of the molecule. A simple colorimeter has been used to monitor atmospheric nitrogen dioxide at ppb level. The air samples were purged through a sampling cuvette containing RBH solution using peristaltic pump. The proposed method has been successfully applied to monitor the ambient nitrogen dioxide levels at traffic junction points within the city limits and the results obtained are compared with the standard Griess-Ilosvay method.

Multiple capillary biochemical analyzer with barrier member

DOEpatents

Dovichi, N.J.; Zhang, J.Z.

1996-10-22

A multiple capillary biochemical analyzer is disclosed for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal-to-noise ratio. 12 figs.

Multiple capillary biochemical analyzer with barrier member

DOEpatents

Dovichi, Norman J.; Zhang, Jian Z.

1996-01-01

A multiple capillary biochemical analyzer for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal to noise ratio.

The Fuge Tube Diode Array Spectrophotometer

ERIC Educational Resources Information Center

Arneson, B. T.; Long, S. R.; Stewart, K. K.; Lagowski, J. J.

2008-01-01

We present the details for adapting a diode array UV-vis spectrophotometer to incorporate the use of polypropylene microcentrifuge tubes--fuge tubes--as cuvettes. Optical data are presented validating that the polyethylene fuge tubes are equivalent to the standard square cross section polystyrene or glass cuvettes generally used in…

Rotor for centrifugal fast analyzers

DOEpatents

Lee, Norman E.

1985-01-01

The invention is an improved photometric analyzer of the rotary cuvette type, the analyzer incorporating a multicuvette rotor of novel design. The rotor (a) is leaktight, (b) permits operation in the 90.degree. and 180.degree. excitation modes, (c) is compatible with extensively used Centrifugal Fast Analyzers, and (d) can be used thousands of times. The rotor includes an assembly comprising a top plate, a bottom plate, and a central plate, the rim of the central plate being formed with circumferentially spaced indentations. A UV-transmitting ring is sealably affixed to the indented rim to define with the indentations an array of cuvettes. The ring serves both as a sealing means and an end window for the cuvettes.

Rotor for centrifugal fast analyzers

DOEpatents

Lee, N.E.

1984-01-01

The invention is an improved photometric analyzer of the rotary cuvette type, the analyzer incorporating a multicuvette rotor of novel design. The rotor (a) is leaktight, (b) permits operation in the 90/sup 0/ and 180/sup 0/ excitation modes, (c) is compatible with extensively used Centrifugal Fast Analyzers, and (d) can be used thousands of times. The rotor includes an assembly comprising a top plate, a bottom plate, and a central plate, the rim of the central plate being formed with circumferentially spaced indentations. A uv-transmitting ring is sealably affixed to the indented rim to define with the indentations an array of cuvettes. The ring serves both as a sealing means and an end window for the cuvettes.

A Continuous Flow System for the Measurement of Ambient Nitrogen Oxides [NO + NO2] Using Rhodamine B Hydrazide as a Chemosensor

PubMed Central

Malingappa, Pandurangappa; Yarradoddappa, Venkataramanappa

2014-01-01

A new chemosensor has been used to monitor atmospheric nitrogen oxides [NO + NO2] at parts per billion (ppb) level. It is based on the catalytic reaction of nitrogen oxides with rhodamine B hydrazide (RBH) to produce a colored compound through the hydrolysis of the amide bond of the molecule. A simple colorimeter has been used to monitor atmospheric nitrogen dioxide at ppb level. The air samples were purged through a sampling cuvette containing RBH solution using peristaltic pump. The proposed method has been successfully applied to monitor the ambient nitrogen dioxide levels at traffic junction points within the city limits and the results obtained are compared with the standard Griess-Ilosvay method. PMID:25210422

Selective plane illumination microscopy (SPIM) with time-domain fluorescence lifetime imaging microscopy (FLIM) for volumetric measurement of cleared mouse brain samples

NASA Astrophysics Data System (ADS)

Funane, Tsukasa; Hou, Steven S.; Zoltowska, Katarzyna Marta; van Veluw, Susanne J.; Berezovska, Oksana; Kumar, Anand T. N.; Bacskai, Brian J.

2018-05-01

We have developed an imaging technique which combines selective plane illumination microscopy with time-domain fluorescence lifetime imaging microscopy (SPIM-FLIM) for three-dimensional volumetric imaging of cleared mouse brains with micro- to mesoscopic resolution. The main features of the microscope include a wavelength-adjustable pulsed laser source (Ti:sapphire) (near-infrared) laser, a BiBO frequency-doubling photonic crystal, a liquid chamber, an electrically focus-tunable lens, a cuvette based sample holder, and an air (dry) objective lens. The performance of the system was evaluated with a lifetime reference dye and micro-bead phantom measurements. Intensity and lifetime maps of three-dimensional human embryonic kidney (HEK) cell culture samples and cleared mouse brain samples expressing green fluorescent protein (GFP) (donor only) and green and red fluorescent protein [positive Förster (fluorescence) resonance energy transfer] were acquired. The results show that the SPIM-FLIM system can be used for sample sizes ranging from single cells to whole mouse organs and can serve as a powerful tool for medical and biological research.

Nanoparticle–Film Plasmon Ruler Interrogated with Transmission Visible Spectroscopy

PubMed Central

2015-01-01

The widespread use of plasmonic nanorulers (PNRs) in sensing platforms has been plagued by technical challenges associated with the development of methods to fabricate precisely controlled nanostructures with high yield and characterize them with high throughput. We have previously shown that creating PNRs in a nanoparticle–film (NP–film) format enables the fabrication of an extremely large population of uniform PNRs with 100% yield using a self-assembly approach, which facilitates high-throughput PNR characterization using ensemble spectroscopic measurements and eliminates the need for expensive microscopy systems required by many other PNR platforms. We expand upon this prior work herein, showing that the NP–film PNR can be made compatible with aqueous sensing studies by adapting it for use in a transmission localized surface plasmon resonance spectroscopy format, where the coupled NP–film resonance responsible for the PNR signal is directly probed using an extinction measurement from a standard spectrophotometer. We designed slide holders that fit inside standard spectrophotometer cuvettes and position NP–film samples so that the coupled NP–film resonance can be detected in a collinear optical configuration. Once the NP–film PNR samples are cuvette-compatible, it is straightforward to calibrate the PNR in aqueous solution and use it to characterize dynamic, angstrom-scale distance changes resulting from pH-induced swelling of polyelectrolyte (PE) spacer layers as thin as 1 PE layer and also of a self-assembled monolayer of an amine-terminated alkanethiol. This development is an important step toward making PNR sensors more user-friendly and encouraging their widespread use in various sensing schemes. PMID:25541618

Reduction of molecular gas diffusion through gaskets in leaf gas exchange cuvettes by leaf-mediated pores.

PubMed

Boesgaard, Kristine S; Mikkelsen, Teis N; Ro-Poulsen, Helge; Ibrom, Andreas

2013-07-01

There is an ongoing debate on how to correct leaf gas exchange measurements for the unavoidable diffusion leakage that occurs when measurements are done in non-ambient CO2 concentrations. In this study, we present a theory on how the CO2 diffusion gradient over the gasket is affected by leaf-mediated pores (LMP) and how LMP reduce diffusive exchange across the gaskets. Recent discussions have so far neglected the processes in the quasi-laminar boundary layer around the gasket. Counter intuitively, LMP reduce the leakage through gaskets, which can be explained by assuming that the boundary layer at the exterior of the cuvette is enriched with air from the inside of the cuvette. The effect can thus be reduced by reducing the boundary layer thickness. The theory clarifies conflicting results from earlier studies. We developed leaf adaptor frames that eliminate LMP during measurements on delicate plant material such as grass leaves with circular cross section, and the effectiveness is shown with respiration measurements on a harp of Deschampsia flexuosa leaves. We conclude that the best solution for measurements with portable photosynthesis systems is to avoid LMP rather than trying to correct for the effects. © 2013 John Wiley & Sons Ltd.

Biogenic Volatile Organic Compound (BVOC) emissions from agricultural crop species: is guttation a possible source for methanol emissions following light/dark transition ?

NASA Astrophysics Data System (ADS)

Mozaffar, Ahsan; Amelynck, Crist; Bachy, Aurélie; Digrado, Anthony; Delaplace, Pierre; du Jardin, Patrick; Fauconnier, Marie-Laure; Schoon, Niels; Aubinet, Marc; Heinesch, Bernard

2015-04-01

In the framework of the CROSTVOC (CROp STress VOC) project, the exchange of biogenic volatile organic compounds (BVOCs) between two important agricultural crop species, maize and winter wheat, and the atmosphere has recently been measured during an entire growing season by using the eddy covariance technique. Because of the co-variation of BVOC emission drivers in field conditions, laboratory studies were initiated in an environmental chamber in order to disentangle the responses of the emissions to variations of the individual environmental parameters (such as PPFD and temperature) and to diverse abiotic stress factors. Young plants were enclosed in transparent all-Teflon dynamic enclosures (cuvettes) through which BVOC-free and RH-controlled air was sent. BVOC enriched air was subsequently sampled from the plant cuvettes and an empty cuvette (background) and analyzed for BVOCs in a high sensitivity Proton Transfer Reaction Mass Spectrometer (hs-PTR-MS) and for CO2 in a LI-7000 non-dispersive IR gas analyzer. Emissions were monitored at constant temperature (25 °C) and at a stepwise varying PPFD pattern (0-650 µmol m-2 s-1). For maize plants, sudden light/dark transitions at the end of the photoperiod were accompanied by prompt and considerable increases in methanol (m/z 33) and water vapor (m/z 39) emissions. Moreover, guttation droplets appeared on the sides and the tips of the leaves within a few minutes after light/dark transition. Therefore the assumption has been raised that methanol is also coming out with guttation fluid from the leaves. Consequently, guttation fluid was collected from young maize and wheat plants, injected in an empty enclosure and sampled by PTR-MS. Methanol and a large number of other compounds were observed from guttation fluid. Recent studies have shown that guttation from agricultural crops frequently occurs in field conditions. Further research is required to find out the source strength of methanol emissions by this guttation phenomenon in real environmental conditions.

Direct Measurements of Leaf Level CH4 and CO2 Exchange in a Boreal Forest

NASA Astrophysics Data System (ADS)

Crill, P.; Lindroth, A.; Vestin, P.; Båth, A.

2008-12-01

Reports of aerobic CH4 sources from leaves and litter of a variety of forests and plant functional types have added a potential mystery to our understanding of CH4 dynamics especially if these sources contribute enough to have a significant impact on the global budget. We have made direct measurements of leaf level CH4 and CO2 exchange using a quartz branch cuvette in a boreal forest in Norunda, Sweden since August of this year. The cuvette was temperature controlled and was designed to close for 5 minutes every 30 minutes. Air was circulated to a Los Gatos CH4/CO2 infrared absorption laser spectrometer. Air and cuvette temperatures, PAR and UV radiation (Kipp and Zonen, CUV4; spectral range 300-380 nm) were measured at the branch chamber. The study was made in the Norunda 100 years old stand consisting of a mixture of Scots pine (Pinus sylvestris L.) , Birch (Betula sp.) and Norway spruce (Picea abies (L.) Karst.). The cuvette was moved between trees at roughly 5 day intervals. A null empty cuvette period was included in the rotation. The initial data show the expected CO2 uptake correlated with incident PAR and low rates of emission at night. However, there was no clear pattern of emissions detectable in the CH4. We estimate that we should be able to resolve a change of 0.5 ppbv CH4 min- 1 with our analytical setup. Both the daytime (1000-1600) and nighttime (2200-0400) averages were less than our detection. Even on very sunny days with high PAR and UV flux values, no consistent pattern was detectable. The lack of a distinct signal may be due to the fact that the past month has been very rainy, it is late in the growth season at these latitudes and sun angles are increasing quickly. The trees were at the northern edge of a clearing and we were also measuring mid height (2-3 m) leaves and branches of young trees. The branch cuvette design can also be optimized to improve its sensitivity.

PDMS based photonic lab-on-a-chip for the selective optical detection of heavy metal ions.

PubMed

Ibarlucea, Bergoi; Díez-Gil, César; Ratera, Inma; Veciana, Jaume; Caballero, Antonio; Zapata, Fabiola; Tárraga, Alberto; Molina, Pedro; Demming, Stephanie; Büttgenbach, Stephanus; Fernández-Sánchez, César; Llobera, Andreu

2013-02-21

The selective absorbance detection of mercury(II) (Hg(2+)) and lead(II) (Pb(2+)) ions using ferrocene-based colorimetric ligands and miniaturized multiple internal reflection (MIR) systems implemented in a low-cost photonic lab on a chip (PhLoC) is reported. The detection principle is based on the formation of selective stable complexes between the heavy metal ion and the corresponding ligand. This interaction modulates the ligand spectrum by giving rise to new absorbance bands or wavelength shifting of the existing ones. A comparative study for the detection of Hg(2+) was carried out with two MIR-based PhLoC systems showing optical path lengths (OPLs) of 0.64 cm and 1.42 cm as well as a standard cuvette (1.00 cm OPL). Acetonitrile solutions containing the corresponding ligand and increasing concentrations of the heavy metal ion were pumped inside the systems and the absorbance in the visible region of the spectra was recorded. The optical behaviour of all the tested systems followed the expected Beer-Lambert law. Thus, the best results were achieved with the one with the longest OPL, which showed a linear behaviour in a concentration range of 1 μM-90 μM Hg(2+), a sensitivity of 5.6 × 10(-3) A.U. μM(-1) and a LOD of 2.59 μM (0.49 ppm), this being 1.7 times lower than that recorded with a standard cuvette, and using a sample/reagent volume around 190 times smaller. This microsystem was also applied for the detection of Pb(2+) and a linear behaviour in a concentration range of 3-100 μM was obtained, and a sensitivity of 9.59 × 10(-4) A.U. μM(-1) and a LOD of 4.19 μM (0.868 ppm) were achieved. Such a simple analytical tool could be implemented in portable instruments for automatic in-field measurements and, considering the minute sample and reagent volume required, would enable the deployment of high throughput environmental analysis of these pollutants and other related hazardous species.

Nonintrusive measurement of the liquid refractive index by using properties of the cuvette wall.

PubMed

Xu, Ming; Ren, Junpeng; Miao, Runcai; Zhang, Zongquan

2016-10-01

We present a method of nonintrusive measurement of the refractive index of a liquid in a glass cuvette, which uses some optical properties of the cuvette wall and the principle of total internal reflection. By coating a transmission-scattering paint layer on the outer surface of the cuvette, we transform an incident laser beam into a transmitted scattered light. When the transmitted scattered light reaches the interface between the container wall and the liquid inside, the light beams satisfying the condition of total internal reflection are reflected to the coating layer, automatically forming a circular dark pattern that is related to the refractive index of the liquid. Based on an analytic relation between the diameter of the circular dark pattern and the refractive index of the liquid, we devised a method of in situ nonintrusive refractive index measurement. We tested the effect of several parameters on the measuring accuracy and found that the optimal thickness of the transmission-scattering layer is in the range of 50-70 μm, and the aperture of the diaphragm should be in the range of 0.7-1.0 mm. We measured the refractive indices of ethanol, Coca Cola, and red wine, and achieved an accuracy of ±3×10^-4  RIU (refractive index unit).

Novel method for determination of zinc traces in beverages and water samples by solid surface fluorescence using a conventional quartz cuvette.

PubMed

Talio, María Carolina; Acosta, María Gimena; Acosta, Mariano; Olsina, Roberto; Fernández, Liliana P

2015-05-15

A new method for zinc pre-concentration/separation and determination by molecular fluorescence is proposed. The metal was complexed with o-phenanthroline and eosin at pH 7.5 in Tris; a piece of filter paper was used as a solid support and solid fluorescent emission measured using a conventional quartz cuvette. Under optimal conditions, the limits of detection and quantification were 0.36 × 10(-3) and 1.29 × 10(-3) μg L(-1), respectively, and the linear range from 1.29 × 10(-3) to 4.50 μg L(-1). This method showed good sensitivity and selectivity, and it was applied to the determination of zinc in foods and tap water. The absence of filtration reduced the consumption of water and electricity. Additionally, the use of common filter papers makes it a simpler and more rapid alternative to conventional methods, with sensitivity and accuracy similar to atomic spectroscopies using a typical laboratory instrument. Copyright © 2014 Elsevier Ltd. All rights reserved.

Colorimetric Determination of the Iron(III)-Thiocyanate Reaction Equilibrium Constant with Calibration and Equilibrium Solutions Prepared in a Cuvette by Sequential Additions of One Reagent to the Other

ERIC Educational Resources Information Center

Nyasulu, Frazier; Barlag, Rebecca

2011-01-01

The well-known colorimetric determination of the equilibrium constant of the iron(III-thiocyanate complex is simplified by preparing solutions in a cuvette. For the calibration plot, 0.10 mL increments of 0.00100 M KSCN are added to 4.00 mL of 0.200 M Fe(NO[subscript 3])[subscript 3], and for the equilibrium solutions, 0.50 mL increments of…

Uncertainty budgets for liquid waveguide CDOM absorption measurements.

PubMed

Lefering, Ina; Röttgers, Rüdiger; Utschig, Christian; McKee, David

2017-08-01

Long path length liquid waveguide capillary cell (LWCC) systems using simple spectrometers to determine the spectral absorption by colored dissolved organic matter (CDOM) have previously been shown to have better measurement sensitivity compared to high-end spectrophotometers using 10 cm cuvettes. Information on the magnitude of measurement uncertainties for LWCC systems, however, has remained scarce. Cross-comparison of three different LWCC systems with three different path lengths (50, 100, and 250 cm) and two different cladding materials enabled quantification of measurement precision and accuracy, revealing strong wavelength dependency in both parameters. Stable pumping of the sample through the capillary cell was found to improve measurement precision over measurements made with the sample kept stationary. Results from the 50 and 100 cm LWCC systems, with higher refractive index cladding, showed systematic artifacts including small but unphysical negative offsets and high-frequency spectral perturbations due to limited performance of the salinity correction. In comparison, the newer 250 cm LWCC with lower refractive index cladding returned small positive offsets that may be physically correct. After null correction of measurements at 700 nm, overall agreement of CDOM absorption data at 440 nm was found to be within 5% root mean square percentage error.

A new front-face optical cell for measuring weak fluorescent emissions with time resolution in the picosecond time scale.

PubMed

Gryczynski, Z; Bucci, E

1993-11-01

Recent developments of ultrafast fluorimeters allow measuring time-resolved fluorescence on the picosecond time scale. This implies one is able to monitor lifetimes and anisotropy decays of highly quenched systems and of systems that contain fluorophores having lifetimes in the subnanosecond range; both systems that emit weak signals. The combination of weak signals and very short lifetimes makes the measurements prone to distortions which are negligible in standard fluorescence experiments. To cope with these difficulties, we have designed a new optical cell for front-face optics which offers to the excitation beam a horizontal free liquid surface in the absence of interactions with optical windows. The new cell has been tested with probes of known lifetimes and anisotropies. It proved very useful in detecting tryptophan fluorescence in hemoglobin. If only diluted samples are available, which cannot be used in front-face optics, regular square geometry can still be utilized by inserting light absorbers into a cuvette of 1 cm path length.

Low-Cost GRIN-Lens-Based Nephelometric Turbidity Sensing in the Range of 0.1-1000 NTU.

PubMed

Metzger, Michael; Konrad, Alexander; Blendinger, Felix; Modler, Andreas; Meixner, Alfred J; Bucher, Volker; Brecht, Marc

2018-04-06

Turbidity sensing is very common in the control of drinking water. Furthermore, turbidity measurements are applied in the chemical (e.g., process monitoring), pharmaceutical (e.g., drug discovery), and food industries (e.g., the filtration of wine and beer). The most common measurement technique is nephelometric turbidimetry. A nephelometer is a device for measuring the amount of scattered light of suspended particles in a liquid by using a light source and a light detector orientated in 90° to each other. Commercially available nephelometers cost usually-depending on the measurable range, reliability, and precision-thousands of euros. In contrast, our new developed GRIN-lens-based nephelometer, called GRINephy, combines low costs with excellent reproducibility and precision, even at very low turbidity levels, which is achieved by its ability to rotate the sample. Thereby, many cuvette positions can be measured, which results in a more precise average value for the turbidity calculated by an algorithm, which also eliminates errors caused by scratches and contaminations on the cuvettes. With our compact and cheap Arduino-based sensor, we are able to measure in the range of 0.1-1000 NTU and confirm the ISO 7027-1:2016 for low turbidity values.

Determination of arsenic in ambient water at sub-part-per-trillion levels by hydride generation Pd coated platform collection and GFAAS detection.

PubMed

Liang, L; Lazoff, S; Chan, C; Horvat, M; Woods, J S

1998-11-01

A method for trace determination of total arsenic in ambient waters is described. Arsenic is separated on-line from a large volume water sample by hydride generation and purging, pre-collected on a Pd coated pyrolytic platform cuvette using a simple and inexpensive system, and finally detected by GFAAS. Instrument parameters, hydride generation, transportation, and collection were optimized. The analytical behavior for major species including As(3+), As(5+), monomethyl As (MMA), and dimethyl As (DMA) were investigated individually. Problems arising from use of the system were discussed and eliminated. The necessity of sample digestion and an efficient digestion method were studied. Sample digestion for water with low organic content such as tap water and clean ground water and some clean surface water can be omitted. The method detection limit (MDL) is 0.3 ng l(-1) for a 25 ml water sample. Recoveries close to 100% with R.S.D.<5% can be easily achieved. Typical aqueous samples including tap, ground, lake, river, rain, sewage effluent, and saline water from different origins in the US, China, and Canada were collected and analyzed using ultra clean sampling and analysis techniques. The background levels of As in most water analyzed were established for the first time, and found to be far above the EPA's health effect criteria, 18 ng l(-1).

Opportunities for hydrologic research in the Congo Basin

NASA Astrophysics Data System (ADS)

Alsdorf, Douglas; Beighley, Ed; Laraque, Alain; Lee, Hyongki; Tshimanga, Raphael; O'Loughlin, Fiachra; Mahé, Gil; Dinga, Bienvenu; Moukandi, Guy; Spencer, Robert G. M.

2016-06-01

We review the published results on the Congo Basin hydrology and summarize the historic and ongoing research. Annual rainfall is ~1900 mm/yr along an east-west trend across the basin, decreasing northward and southward to ~1100 mm/yr. Historic studies using lysimeters, pans, and models suggest that the annual potential evapotranspiration varies little across the basin at 1100 to 1200 mm/yr. Over the past century, river discharge data have been collected at hundreds of stream gauges with historic and recent data at 96 locations now publicly available. Congo River discharge at Kinshasa-Brazzaville experienced an increase of 21% during the 1960-1970 decade in comparison to most other decades. Satellite altimetry measurements of high and low flows show that water levels in the "Cuvette Centrale" wetland are 0.5 m to 3.0 m higher in elevation than the immediately adjacent Congo River levels. Wetland water depths are shallow at about a meter and there does not appear to be many sizable channels across the "Cuvette"; thus, wetland flows are diffusive. Cuvette waters alone are estimated to emit about 0.5 Pg CH4 and CO2 equivalents/yr, an amount that is significant compared to global carbon evasions. Using these results, we suggest seven hypotheses that focus on the source of the Cuvette waters and how these leave the wetland, on the river discharge generated by historic rainfall, on the connection between climate change and the rainfall-runoff generated by the migrating "tropical rainbelt," on deforestation and hydroelectric power generation, and on the amount of carbon emitted from Congo waters.

Opportunities for Hydrologic Research in the Congo Basin

NASA Astrophysics Data System (ADS)

Alsdorf, D. E.; Beighley, E.; Laraque, A.; Lee, H.; Tshimanga, R.; O'Loughlin, F.; Mahe, G. M.; Dinga, B. J.; Moukandi, G.; Spencer, R.

2016-12-01

We review the published results on the Congo Basin hydrology and summarize the historic and ongoing research. Annual rainfall is 1900 mm/yr along an east-west trend across the basin, decreasing northward and southward to 1100 mm/yr. Historic studies using lysimeters, pans, and models suggest that the annual potential evapotranspiration varies little across the basin at 1100 to 1200 mm/yr. Over the past century, river discharge data have been collected at hundreds of stream gauges with historic and recent data at 96 locations now publicly available. Congo River discharge at Kinshasa-Brazzaville experienced an increase of 21% during the 1960-1970 decade in comparison to most other decades. Satellite altimetry measurements of high and low flows show that water levels in the "Cuvette Centrale" wetland are 0.5m to 3.0m higher in elevation than the immediately adjacent Congo River levels. Wetland water depths are shallow at about a meter and there does not appear to be many sizable channels across the "Cuvette"; thus, wetland flows are diffusive. Cuvette waters alone are estimated to emit about 0.5 Pg CH4 and CO2 equivalents/yr, an amount that is significant compared to global carbon evasions. Using these results, we suggest seven hypotheses that focus on the source of the Cuvette waters and how these leave the wetland, on the river discharge generated by historic rainfall, on the connection between climate change and the rainfall-runoff generated by the migrating "tropical rainbelt," on deforestation and hydroelectric power generation, and on the amount of carbon emitted from Congo waters.

Acoustically levitated droplets: a contactless sampling method for fluorescence studies.

PubMed

Leiterer, Jork; Grabolle, Markus; Rurack, Knut; Resch-Genger, Ute; Ziegler, Jan; Nann, Thomas; Panne, Ulrich

2008-01-01

Acoustic levitation is used as a new tool to study concentration-dependent processes in fluorescence spectroscopy. With this technique, small amounts of liquid and solid samples can be measured without the need for sample supports or containers, which often limits signal acquisition and can even alter sample properties due to interactions with the support material. We demonstrate that, because of the small sample volume, fluorescence measurements at high concentrations of an organic dye are possible without the limitation of inner-filter effects, which hamper such experiments in conventional, cuvette-based measurements. Furthermore, we show that acoustic levitation of liquid samples provides an experimentally simple way to study distance-dependent fluorescence modulations in semiconductor nanocrystals. The evaporation of the solvent during levitation leads to a continuous increase of solute concentration and can easily be monitored by laser-induced fluorescence.

Simple Modification of Karl-Fischer Titration Method for Determination of Water Content in Colored Samples

PubMed Central

Tavčar, Eva; Turk, Erika; Kreft, Samo

2012-01-01

The most commonly used technique for water content determination is Karl-Fischer titration with electrometric detection, requiring specialized equipment. When appropriate equipment is not available, the method can be performed through visual detection of a titration endpoint, which does not enable an analysis of colored samples. Here, we developed a method with spectrophotometric detection of a titration endpoint, appropriate for moisture determination of colored samples. The reaction takes place in a sealed 4 ml cuvette. Detection is performed at 520 nm. Titration endpoint is determined from the graph of absorbance plotted against titration volume. The method has appropriate reproducibility (RSD = 4.3%), accuracy, and linearity (R 2 = 0.997). PMID:22567558

Construction of a photochemical reactor combining a CCD spectrophotometer and a LED radiation source.

PubMed

Gombár, Melinda; Józsa, Éva; Braun, Mihály; Ősz, Katalin

2012-10-01

An inexpensive photoreactor using LED light sources and a fibre-optic CCD spectrophotometer as a detector was built by designing a special cell holder for standard 1.000 cm cuvettes. The use of this device was demonstrated by studying the aqueous photochemical reaction of 2,5-dichloro-1,4-benzoquinone. The developed method combines the highly quantitative data collection of CCD spectrophotometers with the possibility of illuminating the sample independently of the detecting light beam, which is a substantial improvement of the method using diode array spectrophotometers as photoreactors.

Estimating the Distribution and Production of Microplankton in a Coastal Upwelling Front from the Cellular Content of Guanosine-5’-Triphosphate and Adenosine-5’-Triphosphate.

DTIC Science & Technology

1981-09-01

through a microfine glass fiber tilter (Reeve Angel 984-H with a pore size of approximately 0.45 pnm). This...buffer (pH 7.7) in order to extract the nucleotides present in the water sample. The test tubes containing the extracts were labeled and stored frozen...into a series of disposable glass cuvettes (12x75mm) and placed in a test tube rack in an incubating water bath at 300 C. Each tube was allowed to

Analytical properties of some commercially available nitrate reductase enzymes evaluated as replacements for cadmium in automated, semiautomated, and manual colorimetric methods for determination of nitrate plus nitrite in water

USGS Publications Warehouse

Patton, Charles J.; Kryskalla, Jennifer R.

2013-01-01

A multiyear research effort at the U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL) evaluated several commercially available nitrate reductase (NaR) enzymes as replacements for toxic cadmium in longstanding automated colorimetric air-segmented continuous-flow analyzer (CFA) methods for determining nitrate plus nitrite (NOx) in water. This research culminated in USGS approved standard- and low-level enzymatic reduction, colorimetric automated discrete analyzer NOx methods that have been in routine operation at the NWQL since October 2011. The enzyme used in these methods (AtNaR2) is a product of recombinant expression of NaR from Arabidopsis thaliana (L.) Heynh. (mouseear cress) in the yeast Pichia pastoris. Because the scope of the validation report for these new automated discrete analyzer methods, published as U.S. Geological Survey Techniques and Methods 5–B8, was limited to performance benchmarks and operational details, extensive foundational research with different enzymes—primarily YNaR1, a product of recombinant expression of NaR from Pichia angusta in the yeast Pichia pastoris—remained unpublished until now. This report documents research and development at the NWQL that was foundational to development and validation of the discrete analyzer methods. It includes: (1) details of instrumentation used to acquire kinetics data for several NaR enzymes in the presence and absence of known or suspected inhibitors in relation to reaction temperature and reaction pH; and (2) validation results—method detection limits, precision and bias estimates, spike recoveries, and interference studies—for standard- and low-level automated colorimetric CFA-YNaR1 reduction NOx methods in relation to corresponding USGS approved CFA cadmium-reduction (CdR) NOx methods. The cornerstone of this validation is paired sample statistical and graphical analysis of NOx concentrations from more than 3,800 geographically and seasonally diverse surface-water and groundwater samples that were analyzed in parallel by CFA-CdR and CFA enzyme-reduction methods. Finally, (3) demonstration of a semiautomated batch procedure in which 2-milliliter analyzer cups or disposable spectrophotometer cuvettes serve as reaction vessels for enzymatic reduction of nitrate to nitrite prior to analytical determinations. After the reduction step, analyzer cups are loaded onto CFA, flow injection, or discrete analyzers for simple, rapid, automatic nitrite determinations. In the case of manual determinations, analysts dispense colorimetric reagents into cuvettes containing post-reduction samples, allow time for color to develop, insert cuvettes individually into a spectrophotometer, and record percent transmittance or absorbance in relation to a reagent blank. Data presented here demonstrate equivalent analytical performance of enzymatic reduction NOx methods in these various formats to that of benchmark CFA-CdR NOx methods.

SU-F-T-164: Investigation of PRESAGE Formulation On Signal Quenching in a Proton Beam

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

Carroll, M; Alqathami, M; Ibbott, G

2016-06-15

Purpose: The radiochromic polyurethane PRESAGE by Heuris Pharma has had limited applications with protons because of a dose response dependence on LET resulting in signal quenching in the Bragg peak. This is due to the radical initiator, a halocarbon, radically recombining in high-LET irradiations. This study investigated the use of alternative halocarbons at various chemical concentrations to determine their significance in signal quenching. Methods: PRESAGE was manufactured in-house and cast in small volume cuvettes (1×1×4cm^3). Several compositions were evaluated to determine the influence of the radical initiator component. Mixtures contained one of two halocarbons, chloroform or bromoform, at concentrations ofmore » 5%/10%/15%(w/w). A large volume, cylindrical PRESAGE dosimeter made following the mixture described by Heuris Pharma, 4cm(D)×8.5cm(H), was irradiated with 200-MeV protons to study regions of low- and high-LET along a 10cm spread out Bragg peak isodose profile. Depths corresponding to regions of low quenching (<3%) and high quenching (>20%) were determined. These depths were used for cuvette placement in a solid water phantom. Samples of each formulation were placed at each depth and irradiated to doses between 0 and 10Gy. Results: The cuvettes indicated different levels of quenching for different radical initiator types, concentrations, and total doses. Chloroform formulations showed reduced quenching from 29%(5%-w/w) to 21%(15%-w/w) while bromoform reduced quenching from 27%(5%-w/w) to 17%(15%-w/w). The reduction in quenching was found to be non-linear with concentration of radical initiator. A quenching dose-dependency was also found that changed with formulation. In all cases, quenching was relatively consistent from 0–5Gy but increased at 10Gy. The quenching decreased as concentrations of radical initiator increased. Conclusion: The radical initiator component in PRESAGE is correlated with the signal quenching observed in proton irradiations and formulation adjustments show promise as a method of reducing this quenching. Future work will further investigate concentration limits and optimize the formulation. Grant number 5RO1CA100835.« less

Optical Trapping-Cavity Ringdown Spectroscopy System for Single Aerosol Particle Measurements

DTIC Science & Technology

2015-02-17

ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Final Report REPORT DOCUMENTATION PAGE 11. SPONSOR...focused 532 nm laser ( Bermuda grass smut spores, horizontal illumination at power of 4.5 mW, focus length = 10 mm, UV quartz cuvette is from Starna...Cells, Inc.) (b) Single bioaerosol particles trapped using a focused 405 nm laser ( Bermuda grass smut spores, upward illumination at power of 2.0

A Microscale Spectrophotometric Determination of Water Hardness

NASA Astrophysics Data System (ADS)

Gordon, James S.

2001-08-01

A spectrophotometric titration was performed to determine water hardness. The titration incorporated the traditional titration method employing EDTA as the titrant and calmagite as the indicator. The microscale experiment was carried out in a spectrometer cuvette and made use of a Texas Instruments (TI-83) calculator interfaced through a TI Calculator-Based Laboratory system to a Vernier colorimeter as the detector. Monitoring at 635 nm, one of the colorimeter's fixed wavelengths, was well suited for this analysis. Agreement was found with results from traditional titrations.

3-d brownian motion simulator for high-sensitivity nanobiotechnological applications.

PubMed

Toth, Arpád; Banky, Dániel; Grolmusz, Vince

2011-12-01

A wide variety of nanobiotechnologic applications are being developed for nanoparticle based in vitro diagnostic and imaging systems. Some of these systems make possible highly sensitive detection of molecular biomarkers. Frequently, the very low concentration of the biomarkers makes impossible the classical, partial differential equation-based mathematical simulation of the motion of the nanoparticles involved. We present a three-dimensional Brownian motion simulation tool for the prediction of the movement of nanoparticles in various thermal, viscosity, and geometric settings in a rectangular cuvette. For nonprofit users the server is freely available at the site http://brownian.pitgroup.org.

Computer registration of radioactive indicator-dilution curves.

PubMed

Shepherd, A P; Perry, M A; Alexander, G M; Granger, D N; Riedel, G L; Kvietys, P R; Franke, C P

1983-12-01

A system is described for recording indicator-dilution curves produced by gamma radiation-emitting tracers. The system consists of a flow-through cuvette in a well counter, appropriate commercially available gamma radiation-detecting equipment, an Apple II computer, and a two-channel pulse-counting interface of our own design. With the counting interface and the software described here, an investigator can simultaneously record two indicator-dilution curves produced by gamma emitters. Instead of having to wait hours or days for results, the investigator can watch the data being recorded and display the results in graphic form almost immediately after each injection.

Differences in Steady-State Net Ammonium and Nitrate Influx by Cold- and Warm-Adapted Barley Varieties 1

PubMed Central

Bloom, Arnold J.; Chapin, F. Stuart

1981-01-01

A flowing nutrient culture system permitted relatively rapid determination of the steady-state net nitrogen influx by an intact barley (Hardeum vulgare L. cv Kombar and Olli) plant. Ion-selective electrodes monitored the depletion of ammonium and nitrate from a nutrient solution after a single pass through a root cuvette. Influx at concentrations as low as 4 micromolar was measured. Standard errors for a sample size of three plants were typically less than 10% of the mean. When grown under identical conditions, a variety of barley bred for cold soils had higher nitrogen influx rates at low concentrations and low temperatures than one bred for warm soils, whereas the one bred for warm soils had higher influx rates at high concentrations and high temperatures. Ammonium was more readily absorbed than nitrate by both varieties at all concentrations and temperatures tested. Ammonium and nitrate influx in both varieties were equally inhibited by low temperatures. PMID:16662052

Pulsed near-infrared photoacoustic spectroscopy of blood

NASA Astrophysics Data System (ADS)

Laufer, Jan G.; Elwell, Clare E.; Delpy, Dave T.; Beard, Paul C.

2004-07-01

The aim of this study was to use pulsed near infrared photoacoustic spectroscopy to determine the oxygen saturation (SO2) of a saline suspension of red blood cells in vitro. The photoacoustic measurements were made in a cuvette which formed part of a larger circuit through which the red blood cell suspension was circulated. Oxygen saturation of the red blood cell suspension was altered between 2-3% to 100% in step increments using a membrane oxygenator and at each increment an independent measurement of oxygen saturation was made using a co-oximeter. An optical parametric oscillator laser system provided nanosecond excitation pulses at a number of wavelengths in the near-infrared spectrum (740-1040nm) which were incident on the cuvette. The resulting acoustic signals were detected using a broadband (15MHz) Fabry-Perot polymer film transducer. The optical transport coefficient and amplitude were determined from the acoustic signals as a function of wavelength. These data were then used to calculate the relative concentrations of oxy- and deoxyhaemoglobin, using their known specific absorption coefficients and an empirically determined wavelength dependence of optical scattering over the wavelength range investigated. From this, the oxygen saturation of the suspension was derived with an accuracy of +/-5% compared to the co-oximeter SO2 measurements.

Rapid and Sensitive Colorimetric ELISA using Silver Nanoparticles, Microwaves and Split Ring Resonator Structures

PubMed Central

Addae, Sarah A.; Pinard, Melissa A.; Caglayan, Humeyra; Cakmakyapan, Semih; Caliskan, Deniz; Ozbay, Ekmel; Aslan, Kadir

2010-01-01

We report a new approach to colorimetric Enzyme-Linked Immunosorbent Assay (ELISA) that reduces the total assay time to < 2 min and the lower-detection-limit by 100-fold based on absorbance readout. The new approach combines the use of silver nanoparticles, microwaves and split ring resonators (SRR). The SRR structure is comprised of a square frame of copper thin film (30 µm thick, 1 mm wide, overall length of ~9.4 mm on each side) with a single split on one side, which was deposited onto a circuit board (2×2 cm2). A single micro-cuvette (10 µl volume capacity) was placed in the split of the SRR structures. Theoretical simulations predict that electric fields are focused in and above the micro-cuvette without the accumulation of electrical charge that breaks down the copper film. Subsequently, the walls and the bottom of the micro-cuvette were coated with silver nanoparticles using a modified Tollen’s reaction scheme. The silver nanoparticles served as a mediator for the creation of thermal gradient between the bioassay medium and the silver surface, where the bioassay is constructed. Upon exposure to low power microwave heating, the bioassay medium in the micro-cuvette was rapidly and uniformly heated by the focused electric fields. In addition, the creation of thermal gradient resulted in the rapid assembly of the proteins on the surface of silver nanoparticles without denaturing the proteins. The proof-of-principle of the new approach to ELISA was demonstrated for the detection of a model protein (biotinylated-bovine serum albumin, b-BSA). In this regard, the detection of b-BSA with bulk concentrations (1 µM to 1 pM) was carried out on commercially available 96-well high throughput screening (HTS) plates and silver nanoparticle-deposited SRR structures at room temperature and with microwave heating, respectively. While the room temperature bioassay (without microwave heating) took 70 min to complete, the identical bioassay took < 2 min to complete using the SRR structures (with microwave heating). A lower detection limit of 0.01 nM for b-BSA (100-fold lower than room temperature ELISA) was observed using the SRR structures. PMID:20953346

A ``plasmonic cuvette'': dye chemistry coupled to plasmonic interferometry for glucose sensing

NASA Astrophysics Data System (ADS)

Siu, Vince S.; Feng, Jing; Flanigan, Patrick W.; Palmore, G. Tayhas R.; Pacifici, Domenico

2014-06-01

A non-invasive method for the detection of glucose is sought by millions of diabetic patients to improve personal management of blood glucose over a lifetime. In this work, the synergistic advantage of combining plasmonic interferometry with an enzyme-driven dye assay yields an optical sensor capable of detecting glucose in saliva with high sensitivity and selectivity. The sensor, coined a "plasmonic cuvette," is built around a nano-scale groove-slit-groove (GSG) plasmonic interferometer coupled to an Amplex-red/Glucose-oxidase/Glucose (AR/GOx/Glucose) assay. The proposed device is highly sensitive, with a measured intensity change of 1.7×105%/m (i.e., one order of magnitude more sensitive than without assay) and highly specific for glucose sensing in picoliter volumes, across the physiological range of glucose concentrations found in human saliva (20-240 μm). Real-time glucose monitoring in saliva is achieved by performing a detailed study of the underlying enzyme-driven reactions to determine and tune the effective rate constants in order to reduce the overall assay reaction time to ˜2 min. The results reported suggest that by opportunely choosing the appropriate dye chemistry, a plasmonic cuvette can be turned into a general, real-time sensing scheme for detection of any molecular target, with high sensitivity and selectivity, within extremely low volumes of biological fluid (down to femtoliters). Hereby, we present the results on glucose detection in artificial saliva as a notable and clinically relevant case study.

Enchanced methods of hydrophilized CdSe quantum dots synthesis

NASA Astrophysics Data System (ADS)

Potapkin, D. V.; Zharkova, I. S.; Goryacheva, I. Y.

2015-03-01

Quantum dots are bright and stable fluorescence signal sources, but for most of applications they need an additional hydrophilization step. Unfortunately, most of existing approaches lead to QD's fluorescence quenching, so there is a need for additional enhancing of hydrophilized QD's brightness like UV irradiation, which can be used both on water insoluble QD's with oleic acid ligands (in toluene) and on hydrophilized QD's covered with UV-stable polymer (in aqueous solution). For synthesis of bright water-soluble fluorescent labels CdSe/CdS/ZnS colloidal quantum dots were covered with PAMAM dendrimer and irradiated with UV lamp in quartz cuvettes for 3 hours at the room temperature and then compared with control sample.

Design of Flow Systems for Improved Networking and Reduced Noise in Biomolecular Signal Processing in Biocomputing and Biosensing Applications

PubMed Central

Verma, Arjun; Fratto, Brian E.; Privman, Vladimir; Katz, Evgeny

2016-01-01

We consider flow systems that have been utilized for small-scale biomolecular computing and digital signal processing in binary-operating biosensors. Signal measurement is optimized by designing a flow-reversal cuvette and analyzing the experimental data to theoretically extract the pulse shape, as well as reveal the level of noise it possesses. Noise reduction is then carried out numerically. We conclude that this can be accomplished physically via the addition of properly designed well-mixing flow-reversal cell(s) as an integral part of the flow system. This approach should enable improved networking capabilities and potentially not only digital but analog signal-processing in such systems. Possible applications in complex biocomputing networks and various sense-and-act systems are discussed. PMID:27399702

Fiber optic illumination of a poly(dimethylsiloxane) sheath flow cuvette for diode laser induced fluorescence detection in capillary electrophoresis.

PubMed

Skinner, Cameron D

2015-02-01

A Tee configuration sheath flow cuvette with square cross-section channels has been produced in PDMS for CE detection. The output of a 1.4 W laser diode operating at 450 nm was focused onto the 300 μm core of a 370 μm od fiber optic whose end was inserted into one arm of the Tee for LIF. The optimal configuration had the fiber optic positioned 500 μm downstream from the intersection and the end of the 35 cm 50 μm id 365 μm od capillary just outside the intersection and in the leg of the Tee, resulting in a 90° configuration. Detection limits of 50 and 3 pM and linear calibrations of at least three orders of magnitude were obtained for Lucifer Yellow and fluorescein, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of kinetic phosphorescence analysis for the determination of uranium

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

Croatto, P.V.; Frank, I.W.; Johnson, K.D.

In the past, New Brunswick Laboratory (NBL) has used a fluorometric method for the determination of sub-microgram quantities of uranium. In its continuing effort to upgrade and improve measurement technology, NBL has evaluated the commercially-available KPA-11 kinetic phosphorescence analyzer (Chemchek, Richland, WA). The Chemchek KPA-11 is a bench-top instrument which performs single-measurement, quench-corrected analyses for trace uranium. It incorporates patented kinetic phosphorimetry techniques to measure and analyze sample phosphorescence as a function of time. With laser excitation and time-corrected photon counting, the KPA-11 has a lower detection limit than conventional fluorometric methods. Operated with a personal computer, the state-of-the-art KPA-11more » offers extensive time resolution and phosphorescence lifetime capabilities for additional specificity. Interferences are thereby avoided while obtaining precise measurements. Routine analyses can be easily and effectively accomplished, with the accuracy and precision equivalent to the pulsed-laser fluorometric method presently performed at NBL, without the need for internal standards. Applications of kinetic phosphorimetry at NBL include the measurement of trace level uranium in retention tank, waste samples, and low-level samples. It has also been used to support other experimental activities at NBL by the measuring of nanogram amounts of uranium contamination (in blanks) in isotopic sample preparations, and the determining of elution curves of different ion exchange resins used for uranium purification. In many cases, no pretreatment of samples was necessary except to fume them with nitric acid, and then to redissolve and dilute them to an appropriate concentration with 1 M HNO{sub 3} before measurement. Concentrations were determined on a mass basis ({micro}g U/g of solution), but no density corrections were needed since all the samples (including the samples used for calibration) were in the same density matrix (1 M HNO{sub 3}). A statistical evaluation of the determination of uranium using kinetic phosphorimetry is described in this report, along with a discussion of the method, and an evaluation of the use of plastic versus quartz cuvettes. Measurement with a precision of {+-} 3--4% relative standard deviation (RSD) and an accuracy of better than {+-} 2% relative difference (RD) are obtained in the 0.0006 to 5 {micro}g U/g-solution range. The instrument detection limit is 0.04 ppb (4 x 10{sup {minus}5} {micro}g U/g solution) using quartz cells, and 0.11 ppb (11 x 10{sup {minus}5} {micro}g U/g solution) using disposable methacrylate cuvettes.« less

A new approach to the old problem: Inner filter effect type I and II in fluorescence

NASA Astrophysics Data System (ADS)

Kasparek, Adam; Smyk, Bogdan

2018-06-01

The fluorescence technique is very popular and has been used in many fields of research. It is simple in its assumptions but not very easy to use. One of the main problems is the inner filter effect (IF) I and II which takes place in the cuvette. IF type I is permanently present, but IF type II occurs only when absorption and fluorescence spectra overlap. To avoid IF type I, absorbencies in the cuvette should be smaller than 0.05, which is however very difficult to obtain in many experiments. In this work we propose a new method to solve these problems in the case of a Cary Eclipse fluorimeter, having horizontally-oriented slits, based on old equations developed in the middle of the last century. This method can be applied for other instruments, even these with vertically-oriented beams, because we share scripts written in MATLAB and GRAMS/AI environment. Calculations in our method enable specifying beam geometry parameters in the cuvette, which is necessary to obtain the correct shape and fluorescence intensity of emission and excitation spectra. Such a specific fluorescence intensity dependence on absorbance can, in many cases, afford possibilities to determine the quantum yield (QY) using slopes of the straight-lines, which was demonstrated with the use of Tryptophan (Trp), Tyrosine (Tyr), and Rhodamine B (RhB) solutions. For example, assuming that QY = 0.14 for Tyr, the QY determined for RhB reached QY = 0.71 ± 0.05, although the measurement for Tyr and RhB was performed at a completely different spectral range.

Nicotiana tabacum as model for ozone - plant surface reactions

NASA Astrophysics Data System (ADS)

Jud, Werner; Fischer, Lukas; Wohlfahrt, Georg; Tissier, Alain; Canaval, Eva; Hansel, Armin

2015-04-01

Elevated tropospheric ozone concentrations are considered a toxic threat to plants, responsible for global crop losses with associated economic costs of several billion dollars per year. The ensuing injuries have been related to the uptake of ozone through the stomatal pores and oxidative effects damaging the internal leaf tissue. A striking question of current research is the environment and plant specific partitioning of ozone loss between gas phase, stomatal or plant surface sink terms. Here we show results from ozone fumigation experiments using various Nicotiana Tabacum varieties, whose surfaces are covered with different amounts of unsaturated diterpenoids exuded by their glandular trichomes. Exposure to elevated ozone levels (50 to 150 ppbv) for 5 to 15 hours in an exceptionally clean cuvette system did neither result in a reduction of photosynthesis nor caused any visible leaf damage. Both these ozone induced stress effects have been observed previously in ozone fumigation experiments with the ozone sensitive tobacco line Bel-W3. In our case ozone fumigation was accompanied by a continuous release of oxygenated volatile organic compounds, which could be clearly associated to their condensed phase precursors for the first time. Gas phase reactions of ozone were avoided by choosing a high enough gas exchange rate of the plant cuvette system. In the case of the Ambalema variety, that is known to exude only the diterpenoid cis-abienol, ozone fumigation experiments yield the volatiles formaldehyde and methyl vinyl ketone (MVK). The latter could be unequivocally separated from isomeric methacrolein (MACR) by the aid of a Selective Reagent Ion Time-of-Flight Mass Spectrometer (SRI-ToF-MS), which was switched every six minutes from H3O+ to NO+ primary ion mode and vice versa. Consistent with the picture of an ozone protection mechanism caused by reactive diterpenoids at the leaf surface are the results from dark-light experiments. The ozone loss obtained from the difference of ozone measured before and after the plant cuvette was investigated as a function of stomatal opening. Switching from dark to light conditions and thus opening the stomata only a small increase in ozone loss was observed for the Ambalema variety (25%). In the case of the 3H02 variety, a line known to emit almost no diterpenoids, the ozone loss increased by more than 100% when changing from dark to light conditions. It is anticipated that the described effect is of importance also for other plant species emitting low-volatility unsaturated organic compounds (e.g. in form of exudates or resins).

Polar plot representation of time-resolved fluorescence.

PubMed

Eichorst, John Paul; Wen Teng, Kai; Clegg, Robert M

2014-01-01

Measuring changes in a molecule's fluorescence emission is a common technique to study complex biological systems such as cells and tissues. Although the steady-state fluorescence intensity is frequently used, measuring the average amount of time that a molecule spends in the excited state (the fluorescence lifetime) reveals more detailed information about its local environment. The lifetime is measured in the time domain by detecting directly the decay of fluorescence following excitation by short pulse of light. The lifetime can also be measured in the frequency domain by recording the phase and amplitude of oscillation in the emitted fluorescence of the sample in response to repetitively modulated excitation light. In either the time or frequency domain, the analysis of data to extract lifetimes can be computationally intensive. For example, a variety of iterative fitting algorithms already exist to determine lifetimes from samples that contain multiple fluorescing species. However, recently a method of analysis referred to as the polar plot (or phasor plot) is a graphical tool that projects the time-dependent features of the sample's fluorescence in either the time or frequency domain into the Cartesian plane to characterize the sample's lifetime. The coordinate transformations of the polar plot require only the raw data, and hence, there are no uncertainties from extensive corrections or time-consuming fitting in this analysis. In this chapter, the history and mathematical background of the polar plot will be presented along with examples that highlight how it can be used in both cuvette-based and imaging applications.

A whole-plant chamber system for parallel gas exchange measurements of Arabidopsis and other herbaceous species.

PubMed

Kölling, Katharina; George, Gavin M; Künzli, Roland; Flütsch, Patrick; Zeeman, Samuel C

2015-01-01

Photosynthetic assimilation of carbon is a defining feature of the plant kingdom. The fixation of large amounts of carbon dioxide supports the synthesis of carbohydrates, which make up the bulk of plant biomass. Exact measurements of carbon assimilation rates are therefore crucial due to their impact on the plants metabolism, growth and reproductive success. Commercially available single-leaf cuvettes allow the detailed analysis of many photosynthetic parameters, including gas exchange, of a selected leaf area. However, these cuvettes can be difficult to use with small herbaceous plants such as Arabidopsis thaliana or plants having delicate or textured leaves. Furthermore, data from single leaves can be difficult to scale-up for a plant shoot with a complex architecture and tissues in different physiological states. Therefore, we constructed a versatile system-EGES-1-to simultaneously measure gas exchange in the whole shoots of multiple individual plants. Our system was designed to be able record data continuously over several days. The EGES-1 system yielded comparable measurements for eight plants for up to 6 days in stable, physiologically realistic conditions. The chambers seals have negligible permeability to carbon dioxide and the system is designed so as to detect any bulk-flow air leaks. We show that the system can be used to monitor plant responses to changing environmental conditions, such as changes in illumination or stress treatments, and to compare plants with phenotypically severe mutations. By incorporating interchangeable lids, the system could be used to measure photosynthetic gas exchange in several genera such as Arabidopsis, Nicotiana, Pisum, Lotus and Mesembryanthemum. EGES-1 can be introduced into a variety of growth facilities and measure gas exchange in the shoots diverse plant species grown in different growth media. It is ideal for comparing photosynthetic carbon assimilation of wild-type and mutant plants and/or plants undergoing selected experimental treatments. The system can deliver valuable data for whole-plant growth studies and help understanding mutant phenotypes. Overall, the EGES-1 is complementary to the readily-available single leaf systems that focus more on the photosynthetic process in within the leaf lamina.

Noncontact blood species identification method based on spatially resolved near-infrared transmission spectroscopy

NASA Astrophysics Data System (ADS)

Zhang, Linna; Sun, Meixiu; Wang, Zhennan; Li, Hongxiao; Li, Yingxin; Li, Gang; Lin, Ling

2017-09-01

The inspection and identification of whole blood are crucially significant for import-export ports and inspection and quarantine departments. In our previous research, we proved Near-Infrared diffuse transmitted spectroscopy method was potential for noninvasively identifying three blood species, including macaque, human and mouse, with samples measured in the cuvettes. However, in open sampling cases, inspectors may be endangered by virulence factors in blood samples. In this paper, we explored the noncontact measurement for classification, with blood samples measured in the vacuum blood vessels. Spatially resolved near-infrared spectroscopy was used to improve the prediction accuracy. Results showed that the prediction accuracy of the model built with nine detection points was more than 90% in identification between all five species, including chicken, goat, macaque, pig and rat, far better than the performance of the model built with single-point spectra. The results fully supported the idea that spatially resolved near-infrared spectroscopy method can improve the prediction ability, and demonstrated the feasibility of this method for noncontact blood species identification in practical applications.

Age, extent and carbon storage of the central Congo Basin peatland complex.

PubMed

Dargie, Greta C; Lewis, Simon L; Lawson, Ian T; Mitchard, Edward T A; Page, Susan E; Bocko, Yannick E; Ifo, Suspense A

2017-02-02

Peatlands are carbon-rich ecosystems that cover just three per cent of Earth's land surface, but store one-third of soil carbon. Peat soils are formed by the build-up of partially decomposed organic matter under waterlogged anoxic conditions. Most peat is found in cool climatic regions where unimpeded decomposition is slower, but deposits are also found under some tropical swamp forests. Here we present field measurements from one of the world's most extensive regions of swamp forest, the Cuvette Centrale depression in the central Congo Basin. We find extensive peat deposits beneath the swamp forest vegetation (peat defined as material with an organic matter content of at least 65 per cent to a depth of at least 0.3 metres). Radiocarbon dates indicate that peat began accumulating from about 10,600 years ago, coincident with the onset of more humid conditions in central Africa at the beginning of the Holocene. The peatlands occupy large interfluvial basins, and seem to be largely rain-fed and ombrotrophic-like (of low nutrient status) systems. Although the peat layer is relatively shallow (with a maximum depth of 5.9 metres and a median depth of 2.0 metres), by combining in situ and remotely sensed data, we estimate the area of peat to be approximately 145,500 square kilometres (95 per cent confidence interval of 131,900-156,400 square kilometres), making the Cuvette Centrale the most extensive peatland complex in the tropics. This area is more than five times the maximum possible area reported for the Congo Basin in a recent synthesis of pantropical peat extent. We estimate that the peatlands store approximately 30.6 petagrams (30.6 × 10 15  grams) of carbon belowground (95 per cent confidence interval of 6.3-46.8 petagrams of carbon)-a quantity that is similar to the above-ground carbon stocks of the tropical forests of the entire Congo Basin. Our result for the Cuvette Centrale increases the best estimate of global tropical peatland carbon stocks by 36 per cent, to 104.7 petagrams of carbon (minimum estimate of 69.6 petagrams of carbon; maximum estimate of 129.8 petagrams of carbon). This stored carbon is vulnerable to land-use change and any future reduction in precipitation.

A new approach to the old problem: Inner filter effect type I and II in fluorescence.

PubMed

Kasparek, Adam; Smyk, Bogdan

2018-06-05

The fluorescence technique is very popular and has been used in many fields of research. It is simple in its assumptions but not very easy to use. One of the main problems is the inner filter effect (IF) I and II which takes place in the cuvette. IF type I is permanently present, but IF type II occurs only when absorption and fluorescence spectra overlap. To avoid IF type I, absorbencies in the cuvette should be smaller than 0.05, which is however very difficult to obtain in many experiments. In this work we propose a new method to solve these problems in the case of a Cary Eclipse fluorimeter, having horizontally-oriented slits, based on old equations developed in the middle of the last century. This method can be applied for other instruments, even these with vertically-oriented beams, because we share scripts written in MATLAB and GRAMS/AI environment. Calculations in our method enable specifying beam geometry parameters in the cuvette, which is necessary to obtain the correct shape and fluorescence intensity of emission and excitation spectra. Such a specific fluorescence intensity dependence on absorbance can, in many cases, afford possibilities to determine the quantum yield (QY) using slopes of the straight-lines, which was demonstrated with the use of Tryptophan (Trp), Tyrosine (Tyr), and Rhodamine B (RhB) solutions. For example, assuming that QY=0.14 for Tyr, the QY determined for RhB reached QY=0.71±0.05, although the measurement for Tyr and RhB was performed at a completely different spectral range. Copyright © 2018 Elsevier B.V. All rights reserved.

Fourier-Based Diffraction Analysis of Live Caenorhabditis elegans.

PubMed

Magnes, Jenny; Hastings, Harold M; Raley-Susman, Kathleen M; Alivisatos, Clara; Warner, Adam; Hulsey-Vincent, Miranda

2017-09-13

This manuscript describes how to classify nematodes using temporal far-field diffraction signatures. A single C. elegans is suspended in a water column inside an optical cuvette. A 632 nm continuous wave HeNe laser is directed through the cuvette using front surface mirrors. A significant distance of at least 20-30 cm traveled after the light passes through the cuvette ensures a useful far-field (Fraunhofer) diffraction pattern. The diffraction pattern changes in real time as the nematode swims within the laser beam. The photodiode is placed off-center in the diffraction pattern. The voltage signal from the photodiode is observed in real time and recorded using a digital oscilloscope. This process is repeated for 139 wild type and 108 "roller" C. elegans. Wild type worms exhibit a rapid oscillation pattern in solution. The "roller" worms have a mutation in a key component of the cuticle that interferes with smooth locomotion. Time intervals that are not free of saturation and inactivity are discarded. It is practical to divide each average by its maximum to compare relative intensities. The signal for each worm is Fourier transformed so that the frequency pattern for each worm emerges. The signal for each type of worm is averaged. The averaged Fourier spectra for the wild type and the "roller" C. elegans are distinctly different and reveal that the dynamic worm shapes of the two different worm strains can be distinguished using Fourier analysis. The Fourier spectra of each worm strain match an approximate model using two different binary worm shapes that correspond to locomotory moments. The envelope of the averaged frequency distribution for actual and modeled worms confirms the model matches the data. This method can serve as a baseline for Fourier analysis for many microscopic species, as every microorganism will have its unique Fourier spectrum.

Flow-batch analysis of clenbuterol based on analyte extraction on molecularly imprinted polymers coupled to an in-system chromogenic reaction. Application to human urine and milk substitute samples.

PubMed

González, Natalia; Grünhut, Marcos; Šrámková, Ivana; Lista, Adriana G; Horstkotte, Burkhard; Solich, Petr; Sklenářová, Hana; Acebal, Carolina C

2018-02-01

A fully automated spectrophotometric method based on flow-batch analysis has been developed for the determination of clenbuterol including an on-line solid phase extraction using a molecularly imprinted polymer (MIP) as the sorbent. The molecularly imprinted solid phase extraction (MISPE) procedure allowed analyte extraction from complex matrices at low concentration levels and with high selectivity towards the analyte. The MISPE procedure was performed using a commercial MIP cartridge that was introduced into a guard column holder and integrated in the analyzer system. Optimized parameters included the volume of the sample, the type and volume of the conditioning and washing solutions, and the type and volume of the eluent. Quantification of clenbuterol was carried out by spectrophotometry after in-system post-elution analyte derivatization based on azo-coupling using N- (1-Naphthyl) ethylenediamine as the coupling agent to yield a red-colored compound with maximum absorbance at 500nm. Both the chromogenic reaction and spectrophotometric detection were performed in a lab-made flow-batch mixing chamber that replaced the cuvette holder of the spectrophotometer. The calibration curve was linear in the 0.075-0.500mgL -1 range with a correlation coefficient of 0.998. The precision of the proposed method was evaluated in terms of the relative standard deviation obtaining 1.1% and 3.0% for intra-day precision and inter-day precision, respectively. The detection limit was 0.021mgL -1 and the sample throughput for the entire process was 3.4h -1 . The proposed method was applied for the determination of CLB in human urine and milk substitute samples obtaining recoveries values within a range of 94.0-100.0%. Copyright © 2017 Elsevier B.V. All rights reserved.

Continuous optical measurement system of hemolysis during a photosensitization reaction using absorption spectrum

NASA Astrophysics Data System (ADS)

Hamada, R.; Ogawa, E.; Arai, T.

2018-02-01

To investigate hemolysis phenomena during a photosensitization reaction with the reaction condition continuously and simultaneously for a safety assessment of hemolysis side effect, we constructed an optical system to measure blood sample absorption spectrum during the reaction. Hemolysis degree might be under estimated in general evaluation methods because there is a constant oxygen pressure assumption in spite of oxygen depression take place. By investigating hemoglobin oxidation and oxygen desorption dynamics obtained from the contribution of the visible absorption spectrum and multiple regression analysis, both the hemolysis phenomena and its oxygen environment might be obtained with time. A 664 nm wavelength laser beam for the reaction excitation and 475-650 nm light beam for measuring the absorbance spectrum were arranged perpendicularly crossing. A quartz glass cuvette with 1×10 mm in dimensions for the spectrum measurement was located at this crossing point. A red blood cells suspension medium was arranged with low hematocrit containing 30 μg/ml talaporfin sodium. This medium was irradiated up to 40 J/cm2 . The met-hemoglobin, oxygenatedhemoglobin, and deoxygenated-hemoglobin concentrations were calculated by a multiple regression analysis from the measured spectra. We confirmed the met-hemoglobin concentration increased and oxygen saturation decreased with the irradiation time, which seems to indicate the hemolysis progression and oxygen consumption, respectively. By using our measuring system, the hemolysis progression seems to be obtained with oxygen environment information.

Monitoring of heparin concentration in serum by Raman spectroscopy within hollow core photonic crystal fiber

NASA Astrophysics Data System (ADS)

Khetani, Altaf; Tiwari, Vidhu S.; Harb, Alaa; Anis, Hanan

2011-08-01

The feasibility of using hollow core photonic crystal fiber (HC-PCF) in conjunction with Raman spectroscopy has been explored for real time monitoring of heparin concentration in serum. Heparin is an important blood anti-coagulant whose precise monitoring and controlling in patients undergoing cardiac surgery and dialysis is of utmost importance. Our method of heparin monitoring offers a novel alternative to existing clinical procedures in terms of accuracy, response time and sample volume. The optical design configuration simply involves a 785-nm laser diode whose light is coupled into HC-PCF filled with heparin-serum mixtures. By non-selectively filling HC-PCF, a strong modal field overlap is obtained. Consequently, an enhanced Raman signal (>90 times) is obtained from various heparin-serum mixtures filled HC-PCFs compared to its bulk counterpart (cuvette). The present scheme has the potential to serve as a `generic biosensing tool' for diagnosing a wide range of biological samples.

Sample exchange by beam scanning with applications to noncollinear pump-probe spectroscopy at kilohertz repetition rates.

PubMed

Spencer, Austin P; Hill, Robert J; Peters, William K; Baranov, Dmitry; Cho, Byungmoon; Huerta-Viga, Adriana; Carollo, Alexa R; Curtis, Anna C; Jonas, David M

2017-06-01

In laser spectroscopy, high photon flux can perturb the sample away from thermal equilibrium, altering its spectroscopic properties. Here, we describe an optical beam scanning apparatus that minimizes repetitive sample excitation while providing shot-to-shot sample exchange for samples such as cryostats, films, and air-tight cuvettes. In this apparatus, the beam crossing point is moved within the focal plane inside the sample by scanning both tilt angles of a flat mirror. A space-filling spiral scan pattern was designed that efficiently utilizes the sample area and mirror scanning bandwidth. Scanning beams along a spiral path is shown to increase the average number of laser shots that can be sampled before a spot on the sample cell is resampled by the laser to ∼1700 (out of the maximum possible 2500 for the sample area and laser spot size) while ensuring minimal shot-to-shot spatial overlap. Both an all-refractive version and an all-reflective version of the apparatus are demonstrated. The beam scanning apparatus does not measurably alter the time delay (less than the 0.4 fs measurement uncertainty), the laser focal spot size (less than the 2 μm measurement uncertainty), or the beam overlap (less than the 3.3% measurement uncertainty), leading to pump-probe and autocorrelation signal transients that accurately characterize the equilibrium sample.

Blood circulatory system for noninvasive diagnostics

NASA Astrophysics Data System (ADS)

Fricke, D.; Kraitl, J.; Ewald, H.

2013-02-01

Based on the human circulatory system, an artificial blood circulatory system was developed to allow the controlled variation of the following blood parameters: total hemoglobin concentration (ctHb), oxyhemoglobin (O2Hb) methemoglobin (MetHb) and carboxyhemoglobin (COHb). The optical properties of the blood were observed by online spectrometer measurements. The purpose of this was to observe and quantify the absorption, transmission and scattering properties of human whole blood in the wavelength range of 400 to 1700 nm. All the non-invasive measurements of the whole blood transmission-spectra were compared with sample results obtained by a Blood Gas Analyzer (BGA) to validate the results. For all measurements, donor erythrocyte concentrates were used. The concentration of hemoglobin was changed by adding fixed amounts of blood plasma to the erythrocyte concentrate. Oxygen saturation and COHb were adjusted by a continuous flow of N2, N2-CO and compressed air through a hollow fibre membrane oxygenator. Different methemoglobin concentrations were adjusted by using natrium nitrite. The blood temperature was kept constant at 37 °C via a tube heating mechanism, with a separate circulation of water passing through the membrane Oxygenator. The Temperature and pressure of the system were automatically controlled and monitored. The model was also used to test new non-invasive measurement systems, and for this reason special cuvettes were designed to imitate human tissue and generate plethysmographical signals. In the future, the blood circulatory system has the potential to be used for testing, validating and also to calibrate newly developed optical prototype devices. It can also be used to further investigate blood components of interest.

A DNA Melting Exercise for a Large Laboratory Class

ERIC Educational Resources Information Center

Levine, Lauren A.; Junker, Matthew; Stark, Myranda; Greenleaf, Dustin

2015-01-01

A simple and economical experimental setup is described that enables multiple individuals or groups within a laboratory class to measure the thermal melting of double stranded DNA simultaneously. The setup utilizes a basic spectrophotometer capable of measuring absorbance at 260 nm, UV plastic cuvettes, and a stirring hot plate. Students measure…

Employing Magnetic Levitation to Monitor Reaction Kinetics and Measure Activation Energy

ERIC Educational Resources Information Center

Benz, Lauren; Cesafsky, Karen E.; Le, Tran; Park, Aileen; Malicky, David

2012-01-01

This article describes a simple and inexpensive undergraduate-level kinetics experiment that uses magnetic levitation to monitor the progress and determine the activation energy of a condensation reaction on a polymeric solid support. The method employs a cuvette filled with a paramagnetic solution positioned between two strong magnets. The…

3D-Printing inside the Glovebox: A Versatile Tool for Inert-Gas Chemistry Combined with Spectroscopy.

PubMed

Lederle, Felix; Kaldun, Christian; Namyslo, Jan C; Hübner, Eike G

2016-04-01

3D-Printing with the well-established 'Fused Deposition Modeling' technology was used to print totally gas-tight reaction vessels, combined with printed cuvettes, inside the inert-gas atmosphere of a glovebox. During pauses of the print, the reaction flasks out of acrylonitrile butadiene styrene were filled with various reactants. After the basic test reactions to proof the oxygen tightness and investigations of the influence of printing within an inert-gas atmosphere, scope and limitations of the method are presented by syntheses of new compounds with highly reactive reagents, such as trimethylaluminium, and reaction monitoring via UV/VIS, IR, and NMR spectroscopy. The applicable temperature range, the choice of solvents, the reaction times, and the analytical methods have been investigated in detail. A set of reaction flasks is presented, which allow routine inert-gas syntheses and combined spectroscopy without modifications of the glovebox, the 3D-printer, or the spectrometers. Overall, this demonstrates the potential of 3D-printed reaction cuvettes to become a complementary standard method in inert-gas chemistry.

Wide-field fluorescent microscopy on a cell-phone.

PubMed

Zhu, Hongying; Yaglidere, Oguzhan; Su, Ting-Wei; Tseng, Derek; Ozcan, Aydogan

2011-01-01

We demonstrate wide-field fluorescent imaging on a cell-phone, using compact and cost-effective optical components that are mechanically attached to the existing camera unit of the cell-phone. Battery powered light-emitting diodes (LEDs) are used to side-pump the sample of interest using butt-coupling. The pump light is guided within the sample cuvette to excite the specimen uniformly. The fluorescent emission from the sample is then imaged with an additional lens that is put in front of the existing lens of the cell-phone camera. Because the excitation occurs through guided waves that propagate perpendicular to the detection path, an inexpensive plastic color filter is sufficient to create the dark-field background needed for fluorescent imaging. The imaging performance of this light-weight platform (~28 grams) is characterized with red and green fluorescent microbeads, achieving an imaging field-of-view of ~81 mm(2) and a spatial resolution of ~10 μm, which is enhanced through digital processing of the captured cell-phone images using compressive sampling based sparse signal recovery. We demonstrate the performance of this cell-phone fluorescent microscope by imaging labeled white-blood cells separated from whole blood samples as well as water-borne pathogenic protozoan parasites such as Giardia Lamblia cysts.

Design of a simple cryogenic system for ultraviolet-visible absorption spectroscopy with a back-reflectance fiber optic probe.

PubMed

Vinyard, Andrew; Hansen, Kaj A; Byrd, Ross; Stuart, Douglas A; Hansen, John E

2014-01-01

We report a convenient and inexpensive technique for the rapid acquisition of absorption spectra from small samples at cryogenic temperatures using a home built cryostat with novel collection optics. A cylindrical copper block was constructed with a coaxial bore to hold a 4.00 mm diameter electron paramagnetic resonance (EPR) tube and mounted on a copper feed in thermal contact with liquid nitrogen. A 6.35 mm diameter hole was bored into the side of the cylinder so a fiber optic cable bundle could be positioned orthogonally to the EPR tube. The light passing through the sample is reflected off of the opposing surfaces of the EPR tube and surrounding copper, back through the sample. The emergent light is then collected using the fiber optic bundle and analyzed using a dispersive spectrometer. Absorption spectra for KMnO4 were measured between 400 and 700 nm. Absorption intensity at 506, 525, 545, and 567 nm was found to be proportional to concentration, displaying Beer's law-like behavior. The EPR tube had an internal diameter of 3.2 mm; the double pass of the probe beam through the sample affords a central path length of about 6.4 mm. Comparing these measurements with those recorded on a conventional tabletop spectrometer using a cuvette with a 10.00 mm path length, we consistently found a ratio between intensities of 0.58 rather than the anticipated 0.64. These 6% smaller values we attribute to the curvature of the EPR tube and transmission/reflection losses. This system is particularly well-suited to studying the kinetics and dynamics of chemical reactions at cryogenic temperatures. The rapid response (100 ms) and multiplex advantage provided the opportunity of recording simultaneous time courses at several wavelengths following initiation of a chemical reaction with a pulsed laser source.

Toward establishing model organisms for marine protists: Successful transfection protocols for Parabodo caudatus (Kinetoplastida: Excavata).

PubMed

Gomaa, Fatma; Garcia, Paulo A; Delaney, Jennifer; Girguis, Peter R; Buie, Cullen R; Edgcomb, Virginia P

2017-09-01

We developed protocols for, and demonstrated successful transfection of, the free-living kinetoplastid flagellate Parabodo caudatus with three plasmids carrying a fluorescence reporter gene (pEF-GFP with the EF1 alpha promoter, pUB-GFP with Ubiquitin C promoter, and pEYFP-Mitotrap with CMV promoter). We evaluated three electroporation approaches: (1) a square-wave electroporator designed for eukaryotes, (2) a novel microfluidic transfection system employing hydrodynamically-controlled electric field waveforms, and (3) a traditional exponential decay electroporator. We found the microfluidic device provides a simple and efficient platform to quickly test a wide range of electric field parameters to find the optimal set of conditions for electroporation of target species. It also allows for processing large sample volumes (>10 ml) within minutes, increasing throughput 100 times over cuvettes. Fluorescence signal from the reporter gene was detected a few hours after transfection and persisted for 3 days in cells transfected by pEF-GFP and pUB-GFP plasmids and for at least 5 days post-transfection for cells transfected with pEYFP-Mitotrap. Expression of the reporter genes (GFP and YFP) was also confirmed using reverse transcription-PCR (RT-PCR). This work opens the door for further efforts with this taxon and close relatives toward establishing model systems for genome editing. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

CVB: the Constrained Vapor Bubble Capillary Experiment on the International Space Station MARANGONI FLOW REGION

NASA Technical Reports Server (NTRS)

Wayner, Peter C., Jr.; Kundan, Akshay; Plawsky, Joel

2014-01-01

The Constrained Vapor Bubble (CVB) is a wickless, grooved heat pipe and we report on a full- scale fluids experiment flown on the International Space Station (ISS). The CVB system consists of a relatively simple setup a quartz cuvette with sharp corners partially filled with either pentane or an ideal mixture of pentane and isohexane as the working fluids. Along with temperature and pressure measurements, the two-dimensional thickness profile of the menisci formed at the corners of the quartz cuvette was determined using the Light Microscopy Module (LMM). Even with the large, millimeter dimensions of the CVB, interfacial forces dominate in these exceedingly small Bond Number systems. The experiments were carried out at various power inputs. Although conceptually simple, the transport processes were found to be very complex with many different regions. At the heated end of the CVB, due to a high temperature gradient, we observed Marangoni flow at some power inputs. This region from the heated end to the central drop region is defined as a Marangoni dominated region. We present a simple analysis based on interfacial phenomena using only measurements from the ISS experiments that lead to a predictive equation for the thickness of the film near the heated end of the CVB. The average pressure gradient for flow in the film is assumed due to the measured capillary pressure at the two ends of the liquid film and that the pressure stress gradient due to cohesion self adjusts to a constant value over a distance L. The boundary conditions are the no slip condition at the wall interface and an interfacial shear stress at the liquid- vapor interface due to the Marangoni stress, which is due to the high temperature gradient. Although the heated end is extremely complex, since it includes three- dimensional variations in radiation, conduction, evaporation, condensation, fluid flow and interfacial forces, we find that using the above simplifying assumptions, a simple successful model can be developed.

SU-E-T-274: Does Atmospheric Oxygen Affect the PRESAGE Dosimeter?

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

Alqathami, M; Ibbott, G; Blencowe, A

Purpose: To experimentally determine the influence of atmospheric oxygen on the efficiency of the PRESAGE dosimeter and its reporting system. Methods: Batches of the reporting system – a mixture of chloroform and leuchomalachite green dye – and PRESAGE were prepared in aerobic and anaerobic conditions. For anaerobic batches, samples were deoxygenated by bubbling nitrogen through the dosimeter precursors or reporting system for 10 min. The dosimeters and reporting systems were prepared in spectrophotometric cuvettes and glass vials, respectively, and were irradiated with 6 MV photons to various radiation doses using a clinical linear accelerator. Changes in optical density of themore » dosimeters and reporting system before and after irradiation were measured using a spectrophotometer. In addition, the concentrations of dissolved oxygen were measured using a dissolved oxygen meter. Results: The experiments revealed that oxygen has little influence on the characteristics of PRESAGE, with the radical initiator oxidizing the leucomalachite green even in the presence of oxygen. However, deoxygenation of the reporting system leads to an increase in sensitivity to radiation dose by ∼ 30% when compared to the non-deoxygenated system. A slight improvement in sensitivity (∼ 5%) was also achieved by deoxygenating the PRESAGE precursor prior to casting. Measurement of the dissolved oxygen revealed low levels (0.4 ppm) in the polyurethane precursor used to fabricate the dosimeters, as compared to water (8.6 ppm). In addition, deoxygenation had no effect on the retention of the post-response absorption value of the PRESAGE dosimeter. Conclusion: The results suggest that the presence of oxygen does not inhibit the radiochromic properties of the PRESAGE system. In addition, there were no observed changes in the dose linearity, absorption spectrum and post-response photofading characteristics of the PRESAGE under the conditions investigated.« less

A ratiometric fluorescent molecular probe for visualization of mitochondrial temperature in living cells.

PubMed

Homma, Mitsumasa; Takei, Yoshiaki; Murata, Atsushi; Inoue, Takafumi; Takeoka, Shinji

2015-04-11

Mitochondrial thermodynamics is the key to understand cellular activities related to homeostasis and energy balance. Here, we report the first ratiometric fluorescent molecular probe (Mito-RTP) that is selectively localized in the mitochondria and visualize the temperature. We confirmed that Mito-RTP could work as a ratiometric thermometer in a cuvette and living cells.

Fluorescence correlation spectroscopy: Ultrasensitive detection in clear and turbid media

NASA Astrophysics Data System (ADS)

Tahari, Abdel Kader

In this work, I describe the development of a simple, inexpensive, and powerful alternative technique to detect and analyze, without enrichment, extremely low concentrations of cells, bacteria, viruses, and protein aggregates in turbid fluids for clinical and biotechnological applications. The anticipated applications of this technique are many. They range from the determination of the somatic cell count in milk for the dairy industry, to the enumeration and characterization of microorganisms in environmental microbiology and the food industry, and to the fast and ultrasensitive detection of protein aggregates for the diagnosis of Alzheimer's and other neurodegenerative diseases in clinical medicine. A prototype instrument has been built and allowed the detection and quantification of particles down to a few per milliliter in short scanning times. It consists of a small microscope that has a horizontal geometry and a mechanical instrument that holds a cylindrical cuvette (1 cm in diameter) with two motors that provide a rotational and a slower vertical inversion motions. The illumination focus is centered about 200 mum from the wall of the cuvette inside the sample. The total volume that is explored is large (˜1ml/min for bright particles). The data is analyzed with a correlation filter program based on particle passage pattern recognition. I will also describe further work on improving the sensitivity of the technique, expanding it for multiple-species discrimination and enumeration, and testing the prototype device in actual clinical and biotechnological applications. The main clinical application of this project seeks to establish conditions and use this new technique to quantify and size-analyze oligomeric complexes of the Alzheimer's disease beta-peptide in cerebrospinal fluid and other body fluids as a molecular biomarker for persons at risk of Alzheimer's disease dementia. The technology could potentially be extended to the diagnosis and therapeutic monitoring of other protein neurologic diseases where oligomeric forms may play a role.

Strategy for determination of LOD and LOQ values--some basic aspects.

PubMed

Uhrovčík, Jozef

2014-02-01

The paper is devoted to the evaluation of limit of detection (LOD) and limit of quantification (LOQ) values in concentration domain by using 4 different approaches; namely 3σ and 10σ approaches, ULA2 approach, PBA approach and MDL approach. Brief theoretical analyses of all above mentioned approaches are given together with directions for their practical use. Calculations and correct calibration design are exemplified by using of electrothermal atomic absorption spectrometry for determination of lead in drinking water sample. These validation parameters reached 1.6 μg L(-1) (LOD) and 5.4 μg L(-1) (LOQ) by using 3σ and 10σ approaches. For obtaining relevant values of analyte concentration the influence of calibration design and measurement methodology were examined. The most preferred technique has proven to be a method of preconcentration of the analyte on the surface of the graphite cuvette (boost cycle). © 2013 Elsevier B.V. All rights reserved.

An improved microphotometry system for measurement of cytochrome P-450 in hepatocyte cytoplasm.

PubMed

Watanabe, J; Kanamura, S

1991-05-01

To measure cytochrome P-450 (P-450) content in hepatocyte cytoplasm, we developed a dual monochromator-equipped microphotometry system (KWSP-1). Simultaneous measurements of absorbance at 450 and 490 nm with narrow band width (0.5 nm) and small spot size (2 microns) were accomplished by this system. Corresponding fields in serial sections could be easily and rapidly identified under the Nomarski imaging mode of KWSP-1. Photometric accuracy and repeatability of wavelength setting of KWSP-1 were also satisfactory for measurement of P-450. With this system, it is thus possible to measure the extinction of P-450 from many small measuring areas and to precisely determine P-450 content in the cytoplasm of rat hepatocytes. A microphotometric method was developed using cuvette slides and two serial 10-microns thick sections (mapping method). The intracellular distribution of P-450 in individual hepatocytes could be visualized by the mapping method with KWSP-1. However, this method was not applicable to tissue sections containing hemoglobin larger than 4 microM.

Monoterpene emissions from Pinus halepensis forests in a semi-arid region (Israel)

NASA Astrophysics Data System (ADS)

Seco, R.; Karl, T.; Turnipseed, A. A.; Greenberg, J.; Guenther, A. B.; Llusia, J.; Penuelas, J.; Kim, S.; Dicken, U.; Rotenberg, E.; Rohatyn, S.; Preisler, Y.; Yakir, D.

2013-12-01

Atmospheric volatile organic compounds (VOCs) have key environmental and biological roles, and can affect atmospheric chemisty, secondary aerosol formation, and as a consequence also climate. At the same time, global changes in climate arising from human activities can modify the VOC emissions of vegetation in the coming years. Monoterpene emission fluxes were measured during April 2013 at two forests in the semi-arid climate of Israel. Both forests were dominated by the same pine species, Pinus halepensis, but differed in the amount of annual average precipitation received (280 and 800 mm at Yatir and Birya, respectively). Measurements performed included leaf-level sampling as well as canopy-level flux calculations. Leaf level monoterpene emissions were sampled from leaf cuvettes with adsorbent cartridges and later analyzed by GC-MS. Canopy scale fluxes were calculated with the Disjunct Eddy Covariance technique by means of a Quadrupole PTRMS. We report the differences observed between the two forests in terms of photosynthetic activity and monoterpene emissions, aiming to see the effect of the different precipitation regimes at each location.

Detection of amino acid neurotransmitters by surface enhanced Raman scattering and hollow core photonic crystal fiber

NASA Astrophysics Data System (ADS)

Tiwari, Vidhu S.; Khetani, Altaf; Monfared, Ali Momenpour T.; Smith, Brett; Anis, Hanan; Trudeau, Vance L.

2012-03-01

The present work explores the feasibility of using surface enhanced Raman scattering (SERS) for detecting the neurotransmitters such as glutamate (GLU) and gamma-amino butyric acid (GABA). These amino acid neurotransmitters that respectively mediate fast excitatory and inhibitory neurotransmission in the brain, are important for neuroendocrine control, and upsets in their synthesis are also linked to epilepsy. Our SERS-based detection scheme enabled the detection of low amounts of GLU (10-7 M) and GABA (10-4 M). It may complement existing techniques for characterizing such kinds of neurotransmitters that include high-performance liquid chromatography (HPLC) or mass spectrography (MS). This is mainly because SERS has other advantages such as ease of sample preparation, molecular specificity and sensitivity, thus making it potentially applicable to characterization of experimental brain extracts or clinical diagnostic samples of cerebrospinal fluid and saliva. Using hollow core photonic crystal fiber (HC-PCF) further enhanced the Raman signal relative to that in a standard cuvette providing sensitive detection of GLU and GABA in micro-litre volume of aqueous solutions.

Determination of fermentable sugars in beer wort by gold nanoparticles@polydopamine: A layer-by-layer approach for Localized Surface Plasmon Resonance measurements at fixed wavelength.

PubMed

Scarano, S; Pascale, E; Palladino, P; Fratini, E; Minunni, M

2018-06-01

Polydopamine decorated in-situ with Localized Surface Plasmon Resonance (LSPR)-active gold nanoparticles (AuNPs) may extend the applicability of nanoplasmonic materials to original and innovative applications in several fields. Here we report the modification of disposable UV-Vis polystyrene cuvettes with AuNPs@PDA for refractive index LSPR-based measurements. An original layer-by-layer deposition method of PDA followed by AuNPs growth is here developed, showing linear correlation between PDA thickness and optical properties. In particular, the modulation from wavelength sensitivity toward absorbance sensitivity is obtained, allowing measurements at fixed wavelength (578 nm). As applicative example of the photonic cuvettes, the measurement of fermentable sugars in beer wort is here reported. The analytical performance of our approach has been directly compared to portable refractometer of reference, displaying excellent results in terms of the precise estimation of sugars in beer wort (expressed in degrees Brix), reproducibility and sensitivity. The approach may be extended to other materials of interest in LSPR based optical sensors, e.g. optical fibers. Copyright © 2018 Elsevier B.V. All rights reserved.

The time resolved SBS and SRS research in heavy water and its application in CARS

NASA Astrophysics Data System (ADS)

Liu, Jinbo; Gai, Baodong; Yuan, Hong; Sun, Jianfeng; Zhou, Xin; Liu, Di; Xia, Xusheng; Wang, Pengyuan; Hu, Shu; Chen, Ying; Guo, Jingwei; Jin, Yuqi; Sang, Fengting

2018-05-01

We present the time-resolved character of stimulated Brillouin scattering (SBS) and backward stimulated Raman scattering (BSRS) in heavy water and its application in Coherent Anti-Stokes Raman Scattering (CARS) technique. A nanosecond laser from a frequency-doubled Nd: YAG laser is introduced into a heavy water cell, to generate SBS and BSRS beams. The SBS and BSRS beams are collinear, and their time resolved characters are studied by a streak camera, experiment show that they are ideal source for an alignment-free CARS system, and the time resolved property of SBS and BSRS beams could affect the CARS efficiency significantly. By inserting a Dye cuvette to the collinear beams, the time-overlapping of SBS and BSRS could be improved, and finally the CARS efficiency is increased, even though the SBS energy is decreased. Possible methods to improve the efficiency of this CARS system are discussed too.

SU-E-T-675: Remote Dosimetry with a Novel PRESAGE Formulation

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

Mein, S; Juang, T; Malcolm, J

2015-06-15

Purpose: 3D-gel dosimetry provides high-resolution treatment validation; however, scanners aren’t widely available. In remote dosimetry, dosimeters are shipped out from a central base institution to a remote site for irradiation, then shipped back for scanning and analysis, affording a convenient service for treatment validation to institutions lacking the necessary equipment and resources. Previous works demonstrated the high-resolution performance and temporal stability of PRESAGE. Here the newest formulation is investigated for remote dosimetry use. Methods: A new formulation of PRESAGE was created with the aim of improved color stability post irradiation. Dose sensitivity was determined by irradiating cuvettes on a Varianmore » Linac (6MV) from 0–15Gy and measuring change in optical density at 633nm. Sensitivity readings were tracked over time in a temperature control study to determine long-term stability. A large volume study was performed to evaluate the accuracy for remote dosimetry. A 1kg dosimeter was pre-scanned, irradiated on-site with an 8Gy 4field box treatment, post-scanned and shipped to Princess Margaret Hospital for remote reading on an identical scanner. Results: Dose sensitivities ranged from 0.0194–0.0295 ΔOD/(Gy*cm)—similar to previous formulations. Post-irradiated cuvettes stored at 10°C retained 100% initial sensitivity over 5 days and 98.6% over 10 weeks while cuvettes stored at room temperature fell to 95.8% after 5 days and 37.4% after 10 weeks. The immediate and 5-day scans of the 4field box dosimeter data was reconstructed, registered to the corresponding eclipse dose-distribution, and compared with analytical tools in CERR. Immediate and 5-day scans looked visually similar. Line profiles revealed close agreement aside from a slight elevation in dose at the edge in the 5-day readout. Conclusion: The remote dosimetry formulation exhibits excellent temporal stability in small volumes. While immediate and 5-day readout scans of large volume dosimeters show promising agreement, further development is required to reduce an apparent time dependent edge elevation.« less

Analysis and prediction of aperiodic hydrodynamic oscillatory time series by feed-forward neural networks, fuzzy logic, and a local nonlinear predictor

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

Gentili, Pier Luigi, E-mail: pierluigi.gentili@unipg.it; Gotoda, Hiroshi; Dolnik, Milos

Forecasting of aperiodic time series is a compelling challenge for science. In this work, we analyze aperiodic spectrophotometric data, proportional to the concentrations of two forms of a thermoreversible photochromic spiro-oxazine, that are generated when a cuvette containing a solution of the spiro-oxazine undergoes photoreaction and convection due to localized ultraviolet illumination. We construct the phase space for the system using Takens' theorem and we calculate the Lyapunov exponents and the correlation dimensions to ascertain the chaotic character of the time series. Finally, we predict the time series using three distinct methods: a feed-forward neural network, fuzzy logic, and amore » local nonlinear predictor. We compare the performances of these three methods.« less

Do it yourself: optical spectrometer for physics undergraduate instruction in nanomaterial characterization

NASA Astrophysics Data System (ADS)

Yeti Nuryantini, Ade; Cahya Septia Mahen, Ea; Sawitri, Asti; Wahid Nuryadin, Bebeh

2017-09-01

In this paper, we report on a homemade optical spectrometer using diffraction grating and image processing techniques. This device was designed to produce spectral images that could then be processed by measuring signal strength (pixel intensity) to obtain the light source, transmittance, and absorbance spectra of the liquid sample. The homemade optical spectrometer consisted of: (i) a white LED as a light source, (ii) a cuvette or sample holder, (iii) a slit, (iv) a diffraction grating, and (v) a CMOS camera (webcam). In this study, various concentrations of a carbon nanoparticle (CNP) colloid were used in the particle size sample test. Additionally, a commercial optical spectrometer and tunneling electron microscope (TEM) were used to characterize the optical properties and morphology of the CNPs, respectively. The data obtained using the homemade optical spectrometer, commercial optical spectrometer, and TEM showed similar results and trends. Lastly, the calculation and measurement of CNP size were performed using the effective mass approximation (EMA) and TEM. These data showed that the average nanoparticle sizes were approximately 2.4 nm and 2.5 ± 0.3 nm, respectively. This research provides new insights into the development of a portable, simple, and low-cost optical spectrometer that can be used in nanomaterial characterization for physics undergraduate instruction.

Optoelectronic pH Meter: Further Details

NASA Technical Reports Server (NTRS)

Jeevarajan, Antony S.; Anderson, Mejody M.; Macatangay, Ariel V.

2009-01-01

A collection of documents provides further detailed information about an optoelectronic instrument that measures the pH of an aqueous cell-culture medium to within 0.1 unit in the range from 6.5 to 7.5. The instrument at an earlier stage of development was reported in Optoelectronic Instrument Monitors pH in a Culture Medium (MSC-23107), NASA Tech Briefs, Vol. 28, No. 9 (September 2004), page 4a. To recapitulate: The instrument includes a quartz cuvette through which the medium flows as it is circulated through a bioreactor. The medium contains some phenol red, which is an organic pH-indicator dye. The cuvette sits between a light source and a photodetector. [The light source in the earlier version comprised red (625 nm) and green (558 nm) light-emitting diodes (LEDs); the light source in the present version comprises a single green- (560 nm)-or-red (623 nm) LED.] The red and green are repeatedly flashed in alternation. The responses of the photodiode to the green and red are processed electronically to obtain the ratio between the amounts of green and red light transmitted through the medium. The optical absorbance of the phenol red in the green light varies as a known function of pH. Hence, the pH of the medium can be calculated from the aforesaid ratio.

Analysis of polarized-light effects in glass-promoting solutions with applications to cryopreservation and organ banking.

PubMed

Solanki, Prem K; Rabin, Yoed

2018-01-01

This study presents experimental results and an analysis approach for polarized light effects associated with thermomechanical stress during cooling of glass promoting solutions, with applications to cryopreservation and tissue banking in a process known as vitrification. Polarized light means have been previously integrated into the cryomacroscope-a visualization device to detect physical effects associated with cryopreservation success, such as crystallization, fracture formation, and contamination. The experimental study concerns vitrification in a cuvette, which is a rectangular container. Polarized light modeling in the cuvette is based on subdividing the tridimensional (3D) domain into a series of planar (2D) problems, for which a mathematical solution is available in the literature. The current analysis is based on tracking the accumulated changes in light polarization and magnitude, as it passes through the sequence of planar problems. Results of this study show qualitative agreement in light intensity history and distribution between experimental data and simulated results. The simulated results help explaining differences between 2D and 3D effects in photoelasticity, most notably, the counterintuitive observation that high stress areas may correlate with low light intensity regions based on the particular experimental conditions. Finally, it is suggested that polarized-light analysis must always be accompanied by thermomechanical stress modeling in order to explain 3D effects.

Analysis of polarized-light effects in glass-promoting solutions with applications to cryopreservation and organ banking

PubMed Central

2018-01-01

This study presents experimental results and an analysis approach for polarized light effects associated with thermomechanical stress during cooling of glass promoting solutions, with applications to cryopreservation and tissue banking in a process known as vitrification. Polarized light means have been previously integrated into the cryomacroscope—a visualization device to detect physical effects associated with cryopreservation success, such as crystallization, fracture formation, and contamination. The experimental study concerns vitrification in a cuvette, which is a rectangular container. Polarized light modeling in the cuvette is based on subdividing the tridimensional (3D) domain into a series of planar (2D) problems, for which a mathematical solution is available in the literature. The current analysis is based on tracking the accumulated changes in light polarization and magnitude, as it passes through the sequence of planar problems. Results of this study show qualitative agreement in light intensity history and distribution between experimental data and simulated results. The simulated results help explaining differences between 2D and 3D effects in photoelasticity, most notably, the counterintuitive observation that high stress areas may correlate with low light intensity regions based on the particular experimental conditions. Finally, it is suggested that polarized-light analysis must always be accompanied by thermomechanical stress modeling in order to explain 3D effects. PMID:29912973

Cells and biofluids analyzed in aqueous environment by infrared spectroscopy

NASA Astrophysics Data System (ADS)

Naumann, D.; Lasch, P.; Fabian, H.

2006-02-01

Infrared transmission/absorption measurements of cells and biofluids in water are restricted to very short optical pathlengths. When the amide I and amide II bands of protein constituents have to be analysed, path-lengths of less than 8 μm are necessary. Infrared spectra of cancer cells were collected from physiological buffer solutions utilizing custom-made mid-infrared compatible IR-cuvettes. The technology permitted to obtain cell-type specific spectral signatures and probe biochemical changes induced by varying temperatures or cell-drug interaction. Optical path-lengths of 8-30 μm were used on a set of microbial test strains to evaluate, whether the methodology can also be used to discriminate and identify micro-organisms. A semi-automatic methodology was developed for the analysis of liquid serum samples, which combines simple sample handling with high sample throughput and extreme measurement reproducibility. The applicability of this infrared technology to the analysis of liquid serum samples from cattle and human beings suffering from various acute viral or bacterial infections was explored testing the interrelationship between α-helical and β-sheet specific spectral signatures in the amide I band contour and total albumin and globulin content in serum. The technical details, advantages, and limitations of the new technology are described in the context of developing a routine, IR-based biodiagnostic technique for biofluids and biological cells.

An investigation of a PRESAGE® in-vivo dosimeter for brachytherapy

PubMed Central

Vidovic, A K; Juang, T; Meltsner, S; Adamovics, J; Chino, J; Steffey, B; Craciunescu, O; Oldham, M

2014-01-01

Determining accurate in-vivo dosimetry in brachytherapy treatment with high dose gradients is challenging. Here we introduce, investigate, and characterize a novel in-vivo dosimeter and readout technique with the potential to address this problem. A cylindrical (4 mm x 20 mm) tissue equivalent radiochromic dosimeter PRESAGE® In-Vivo (PRESAGE®-IV) is investigated. Two readout methods of the radiation induced change in optical density (OD) were investigated: (i) volume-averaged readout by spectrophotometer, and (ii) a line profile readout by 2D projection imaging utilizing a high-resolution (50 micron) telecentric optical system. Method (i) is considered the gold standard when applied to PRESAGE® in optical cuvettes. The feasibility of both methods was evaluated by comparison to standard measurements on PRESAGE® in optical cuvettes via spectrophotometer. An end-to-end feasibility study was performed by a side-by-side comparison with TLDs in an 192Ir HDR delivery. 7 and 8 Gy was delivered to PRESAGE®-IV and TLDs attached to the surface of a vaginal cylinder. Known geometry enabled direct comparison of measured dose with commissioned treatment planning system. A high-resolution readout study under a steep dose gradient region showed 98.9% (5%/1 mm) agreement between PRESAGE®-IV and Gafchromic® EBT2 Film. Spectrometer measurements exhibited a linear dose response between 0–15 Gy with sensitivity of 0.0133 ± 0.0007 ΔOD/(Gy·cm) at the 95% confidence interval. Method (ii) yielded a linear response with sensitivity of 0.0132 ± 0.0006 (ΔOD/Gy), within 2% of method (i). Method (i) has poor spatial resolution due to volume averaging. Method (ii) has higher resolution (~1mm) without loss of sensitivity or increased noise. Both readout methods are shown to be feasible. The end-to-end comparison revealed a 2.5% agreement between PRESAGE®-IV and treatment plan in regions of uniform high dose. PRESAGE®-IV shows promise for in-vivo dose verification, although improved sensitivity would be desirable. Advantages include high-resolution, convenience and fast, low-cost readout. PMID:24957850

An investigation of a PRESAGE® in vivo dosimeter for brachytherapy

NASA Astrophysics Data System (ADS)

Vidovic, A. K.; Juang, T.; Meltsner, S.; Adamovics, J.; Chino, J.; Steffey, B.; Craciunescu, O.; Oldham, M.

2014-07-01

Determining accurate in vivo dosimetry in brachytherapy treatment with high dose gradients is challenging. Here we introduce, investigate, and characterize a novel in vivo dosimeter and readout technique with the potential to address this problem. A cylindrical (4 mm × 20 mm) tissue equivalent radiochromic dosimeter PRESAGE® in vivo (PRESAGE®-IV) is investigated. Two readout methods of the radiation induced change in optical density (OD) were investigated: (i) volume-averaged readout by spectrophotometer, and (ii) a line profile readout by 2D projection imaging utilizing a high-resolution (50 micron) telecentric optical system. Method (i) is considered the gold standard when applied to PRESAGE® in optical cuvettes. The feasibility of both methods was evaluated by comparison to standard measurements on PRESAGE® in optical cuvettes via spectrophotometer. An end-to-end feasibility study was performed by a side-by-side comparison with TLDs in an 192Ir HDR delivery. 7 and 8 Gy was delivered to PRESAGE®-IV and TLDs attached to the surface of a vaginal cylinder. Known geometry enabled direct comparison of measured dose with a commissioned treatment planning system. A high-resolution readout study under a steep dose gradient region showed 98.9% (5%/1 mm) agreement between PRESAGE®-IV and Gafchromic® EBT2 Film. Spectrometer measurements exhibited a linear dose response between 0-15 Gy with sensitivity of 0.0133 ± 0.0007 ΔOD/(Gy ṡ cm) at the 95% confidence interval. Method (ii) yielded a linear response with sensitivity of 0.0132 ± 0.0006 (ΔOD/Gy), within 2% of method (i). Method (i) has poor spatial resolution due to volume averaging. Method (ii) has higher resolution (˜1 mm) without loss of sensitivity or increased noise. Both readout methods are shown to be feasible. The end-to-end comparison revealed a 2.5% agreement between PRESAGE®-IV and treatment plan in regions of uniform high dose. PRESAGE®-IV shows promise for in vivo dose verification, although improved sensitivity would be desirable. Advantages include high-resolution, convenience and fast, low-cost readout.

Ultrasensitive and high-throughput analysis of chlorophyll a in marine phytoplankton extracts using a fluorescence microplate reader.

PubMed

Mandalakis, Manolis; Stravinskaitė, Austėja; Lagaria, Anna; Psarra, Stella; Polymenakou, Paraskevi

2017-07-01

Chlorophyll a (Chl a) is the predominant pigment in every single photosynthesizing organism including phytoplankton and one of the most commonly measured water quality parameters. Various methods are available for Chl a analysis, but the majority of them are of limited throughput and require considerable effort and time from the operator. The present study describes a high-throughput, microplate-based fluorometric assay for rapid quantification of Chl a in phytoplankton extracts. Microplate sealing combined with ice cooling was proved an effective means for diminishing solvent evaporation during sample loading and minimized the analytical errors involved in Chl a measurements with a fluorescence microplate reader. A set of operating parameters (settling time, detector gain, sample volume) were also optimized to further improve the intensity and reproducibility of Chl a fluorescence signal. A quadratic regression model provided the best fit (r 2  = 0.9998) across the entire calibration range (0.05-240 pg μL -1 ). The method offered excellent intra- and interday precision (% RSD 2.2 to 11.2%) and accuracy (% relative error -3.8 to 13.8%), while it presented particularly low limits of detection (0.044 pg μL -1 ) and quantification (0.132 pg μL -1 ). The present assay was successfully applied on marine phytoplankton extracts, and the overall results were consistent (average % relative error -14.8%) with Chl a concentrations (including divinyl Chl a) measured by high-performance liquid chromatography (HPLC). More importantly, the microplate-based method allowed the analysis of 96 samples/standards within a few minutes, instead of hours or days, when using a traditional cuvette-based fluorometer or an HPLC system. Graphical abstract TChl a concentrations (i.e. sum of Chl a and divinyl Chl a in ng L -1 ) measured in seawater samples by HPLC and fluorescence microplate reader.

Detecting paraprotein interference on a direct bilirubin assay by reviewing the photometric reaction data.

PubMed

García-González, Elena; Aramendía, Maite; González-Tarancón, Ricardo; Romero-Sánchez, Naiara; Rello, Luis

2017-07-26

The direct bilirubin (D-Bil) assay on the AU Beckman Coulter instrumentation can be interfered by paraproteins, which may result in spurious D-Bil results. In a previous work, we took advantage of this fact to detect this interference, thus helping with the identification of patients with unsuspected monoclonal gammopathies. In this work, we investigate the possibility to detect interference based on the review of the photometric reactions, regardless of the D-Bil result. The D-Bil assay was carried out in a set of 2164 samples. It included a group of 164 samples with paraproteins (67 of which caused interference on the assay), as well as different groups of samples for which high absorbance background readings could also be expected (i.e. hemolyzed, lipemic, or icteric samples). Photometric reaction data were reviewed and receiver operating characteristics (ROC) curves were used to establish a cut-off for absorbance that best discriminates interference. The best cut-off was 0.0100 for the absorbance at the first photometric point of the complementary wavelength in the blank cuvette. Once the optimal cut-off for probable interference was selected, all samples analyzed in our laboratory that provided absorbance values above this cut-off were further investigated to try to discover paraproteins. During a period of 6 months, we detected 44 samples containing paraproteins, five of which belonged to patients with non-diagnosed monoclonal gammopathies. Review of the photometric reaction data permits the systematic detection of paraprotein interference on the D-Bil AU assay, even for samples for which reasonable results are obtained.

In situ measurements of root exudation in three hardwood species in southern Indiana

NASA Astrophysics Data System (ADS)

O'Connor, D. A.; Brzostek, E. R.; Fisher, J. B.; Phillips, R.

2012-12-01

Root exudation - the release of soluble organic compounds to soil - has long been considered a black box in ecology owing to methodological difficulties associated with measuring this flux in situ. This knowledge gap is significant given recent findings that suggest exudate inputs are appreciable in magnitude (2-5% of net primary production) and are coupled to microbial activities, nutrient release and soil organic matter decomposition. We developed a novel experimental system for collecting exudates from intact roots of field-grown trees using cuvettes filled with sterile glass beads. We measured root exudation for three tree species in ~80 year old mixed hardwood forest in south central Indiana, USA in the summer of 2012. Exudation rates varied from 0 to 1413 ug C/g root/day, and differed by sampling date and among trees species. Overall, rates were greater in early relative to late July, and greater in sugar maple (Acer saccharum) and white oak (Quercus alba) relative to tulip poplar (Liriodendron tulipifera). Across all species, exudation rates were correlated with root mass, indicating that greater allocation to roots likely increases the amount of C available to fuel soil microbial activity. Collectively, the results of this study should enable us to develop improved model parameterizations of the C costs associated with nutrient acquisition, an important feedback for predicting the role of vegetation in mediating climate change.

Bioenergetic Approaches and Inflammation of MPTP Toxicity

DTIC Science & Technology

2006-09-01

with 8 strokes of pestle A followed by 8 strokes of pestle B. The brain homogenate was centrifuged at 1250 g for 3 min; pellet was discarded and...legends to figures. Fluorescence of safranin O was measured with an F4500 fluorimeter (Hitachi, Japan ) equipped with a magnetic stirring assembly and...and 531 nm emission wavelengths with F4500 fluorimeter (Hitachi, Japan ) equipped with a magnetic stirring assembly and a thermostated cuvette holder

Engineering of Paraoxonases for Pre- and Post-treatment of Intoxication by a Broad Spectrum of Nerve Agents and Pesticides

DTIC Science & Technology

2014-08-01

chemical warfare nerve agents (CWNA). Enzymes identified in these screens should be capable of catalytically neutralizing the target agent under...soluble form. 4. Large-scale production of selected enzyme candidates, and their kinetic, structural and pharmacological evaluation 6...employed, with an enzyme protein concentration of 0.5-2 mM in the assay cuvette, the activity measured was indistinguishable from the rate of

Thermoelectrically controlled device for studies of temperature-induced corneal shrinkage

NASA Astrophysics Data System (ADS)

Borja, David; Manns, Fabrice; Fernandez, Viviana; Lamar, Peggy; Soederberg, Per G.; Parel, Jean-Marie A.

2002-06-01

The purpose of this study was to design and calibrate a device to measure the dynamics of thermal shrinkage in corneal and scleral strips. The apparatus consists of a thermoelectric cell controlled by a temperature controller designed to generate temperatures up to 90 degree(s)C in rectangular corneal strips; a copper cuvette filled with Dextran solution that holds the corneal strip and a displacement sensor that measures the change in length of the tissue during heat-induced shrinkage. The device was tested on corneal tissue from Florida Eye-Bank eyes that were cut into 2x4mm rectangular strips. Preliminary results indicate that our system can reproducibly create and accurately measure thermally induced corneal shrinkage. Shrinkage experiments will be used to optimize laser parameters for corneal shrinkage during laser thermokeratoplasty and laser scleral buckling.

Analysis of UV-excited fluorochromes by flow cytometry using near-ultraviolet laser diodes.

PubMed

Telford, William G

2004-09-01

Violet laser diodes have become common and reliable laser sources for benchtop flow cytometers. While these lasers are very useful for a variety of violet and some ultraviolet-excited fluorochromes (e.g., DAPI), they do not efficiently excite most UV-stimulated probes. In this study, the next generation of InGaN near-UV laser diodes (NUVLDs) emitting in the 370-375-nm range have been evaluated as laser sources for cuvette-based flow cytometers. Several NUVLDs, ranging in wavelength from 370 to 374 nm and in power level from 1.5 to 10 mW, were mounted on a BD Biosciences LSR II and evaluated for their ability to excite cells labeled with the UV DNA binding dye DAPI, several UV phenotyping fluorochromes (including Alexa Fluor 350, Marina Blue, and quantum dots), and the fluorescent calcium chelator indo-1. NUVLDs at the 8-10-mW power range gave detection sensitivity levels comparable to more powerful solid-state and ion laser sources, using low-fluorescence microsphere beads as measurement standards. NUVLDs at all tested power levels allowed extremely high-resolution DAPI cell cycle analysis, and sources in the 8-10-mW power range excited Alexa Fluor 350, Marina Blue, and a variety of quantum dots at virtually the same signal-to-noise ratios as more powerful UV sources. These evaluations indicate that near-UV laser diodes installed on a cuvette-based flow cytometer performed nearly as well as more powerful solid-state UV lasers on the same instrumentation, and comparably to more powerful ion lasers on a jet-in-air system, and. Despite their limited power, integration of these small and inexpensive lasers into benchtop flow cytometers should allow the use of flow cytometric applications requiring UV excitation on a wide variety of instruments. Copyright 2004 Wiley-Liss, Inc.

Phase 2 SBIR Final Report: An Ultra-Sensitive Optical Biosensor for Flood Safety

DTIC Science & Technology

2002-08-23

can be completed in 2 to 4 hours. Currently accepted tests using commercial test kits based on immunochemical techniques offer results in 22 to 24...tagging is imperfect, leading to a background of non-specific surface and molecular binding limiting the signal. The use of a reporter fluorochrome can ...Waveguide Patterning: Surface flow channels: The rectangular cuvettes (as shown in Section II, Figure 4-3) can be etched using standard techniques. The

Measurement of Scattering Cross Section with a Spectrophotometer with an Integrating Sphere Detector

PubMed Central

Gaigalas, A. K.; Wang, Lili; Karpiak, V.; Zhang, Yu-Zhong; Choquette, Steven

2012-01-01

A commercial spectrometer with an integrating sphere (IS) detector was used to measure the scattering cross section of microspheres. Analysis of the measurement process showed that two measurements of the absorbance, one with the cuvette placed in the normal spectrometer position, and the second with the cuvette placed inside the IS, provided enough information to separate the contributions from scattering and molecular absorption. Measurements were carried out with microspheres with different diameters. The data was fitted with a model consisting of the difference of two terms. The first term was the Lorenz-Mie (L-M) cross section which modeled the total absorbance due to scattering. The second term was the integral of the L-M differential cross section over the detector acceptance angle. The second term estimated the amount of forward scattered light that entered the detector. A wavelength dependent index of refraction was used in the model. The agreement between the model and the data was good between 300 nm and 800 nm. The fits provided values for the microsphere diameter, the concentration, and the wavelength dependent index of refraction. For wavelengths less than 300 nm, the scattering cross section had significant spectral structure which was inversely related to the molecular absorption. This work addresses the measurement and interpretation of the scattering cross section for wavelengths between 300 nm and 800 nm. PMID:26900524

Measurement of Scattering Cross Section with a Spectrophotometer with an Integrating Sphere Detector.

PubMed

Gaigalas, A K; Wang, Lili; Karpiak, V; Zhang, Yu-Zhong; Choquette, Steven

2012-01-01

A commercial spectrometer with an integrating sphere (IS) detector was used to measure the scattering cross section of microspheres. Analysis of the measurement process showed that two measurements of the absorbance, one with the cuvette placed in the normal spectrometer position, and the second with the cuvette placed inside the IS, provided enough information to separate the contributions from scattering and molecular absorption. Measurements were carried out with microspheres with different diameters. The data was fitted with a model consisting of the difference of two terms. The first term was the Lorenz-Mie (L-M) cross section which modeled the total absorbance due to scattering. The second term was the integral of the L-M differential cross section over the detector acceptance angle. The second term estimated the amount of forward scattered light that entered the detector. A wavelength dependent index of refraction was used in the model. The agreement between the model and the data was good between 300 nm and 800 nm. The fits provided values for the microsphere diameter, the concentration, and the wavelength dependent index of refraction. For wavelengths less than 300 nm, the scattering cross section had significant spectral structure which was inversely related to the molecular absorption. This work addresses the measurement and interpretation of the scattering cross section for wavelengths between 300 nm and 800 nm.

Optoelectronic Instrument Monitors pH in a Culture Medium

NASA Technical Reports Server (NTRS)

Anderson, Melody M.; Pellis, Neal; Jeevarajan, Anthony S.; Taylor, Thomas D.

2004-01-01

An optoelectronic instrument monitors the pH of an aqueous cell-culture medium in a perfused rotating-wall-vessel bioreactor. The instrument is designed to satisfy the following requirements: It should be able to measure the pH of the medium continuously with an accuracy of 0.1 in the range from 6.5 to 7.5. It should be noninvasive. Any material in contact with the culture medium should be sterilizable as well as nontoxic to the cells to be grown in the medium. The biofilm that inevitably grows on any surface in contact with the medium should not affect the accuracy of the pH measurement. It should be possible to obtain accurate measurements after only one calibration performed prior to a bioreactor cell run. The instrument should be small and lightweight. The instrument includes a quartz cuvette through which the culture medium flows as it is circulated through the bioreactor. The cuvette is sandwiched between light source on one side and a photodetector on the other side. The light source comprises a red and a green light-emitting diode (LED) that are repeatedly flashed in alternation with a cycle time of 5 s. The responses of the photodiode to the green and red LEDs are processed electronically to obtain a quantity proportional to the ratio between the amounts of green and red light transmitted through the medium.

Comparable Monoterpene emission from pine forests across 500 mm precipitation gradient in the semi-arid transition zone

NASA Astrophysics Data System (ADS)

Seco, Roger; Karl, Thomas; Turnipseed, Andrew; Greenberg, Jim; Guenther, Alex; Llusia, Joan; Penuelas, Josep; Dicken, Uri; Rotenberg, Eyal; Rohatyn, Shani; Preisler, Yakir; Yakir, Dan

2014-05-01

Atmospheric volatile organic compounds (VOCs) have key environmental and biological roles, and can affect atmospheric chemistry, secondary aerosol formation, and as a consequence also climate. At the same time, global changes in climate arising from human activities can modify the VOC emissions of vegetation in the coming years. Monoterpene emission fluxes were measured during April 2013 at two forests in the semi-arid climate of Israel. Both forests were dominated by Pinus halepensis trees of similar age, but differed in the amount of annual average precipitation received (~276 and ~760 mm at the Yatir and Birya sites, respectively). Measurements performed included leaf-level sampling and gas exchange, as well as canopy-level flux calculations. Leaf level monoterpene emissions were sampled from leaf cuvettes with adsorbent cartridges and later analyzed by GC-MS. Canopy scale fluxes were calculated with the Disjunct Eddy Covariance technique by means of a Quadrupole PTRMS and eddy-covariance system. We report the differences observed between the two forests in terms of photosynthetic activity and monoterpene emissions, aiming to see the effect of the different climatic regimes at each location. Significantly higher emission rates of monoterpenes were observed in the wetter site during mid-day, in both the leaf scale and canopy scale measurements. Remarkably, however, normalized to 30C and corrected for tree density differences between the sites indicated comparable emission rates for both sites, with higher emission rated in the evening hours in the dry site at the edge of the Negev Desert. Modeling the monoterpene emission rates using MEGAN v2.1 indicated better agreement with observations in the wetter site then in the dry site, especially with respect to fluxes during the evening hours.

Photoacoustic determination of glucose concentration in whole blood by a near-infrared laser diode

NASA Astrophysics Data System (ADS)

Zhao, Zuomin; Myllylae, Risto A.

2001-06-01

The near-infrared photoacoustic technique is recognized as a potential method for the non-invasive determination of human glucose, because near-infrared light can incident a few millimeters into human tissue, where it produces an acoustic wave capable of carrying information about the composition of the tissue. This paper demonstrates a photoacoustic glucose measurement in a blood sample as a step toward a non-invasive measurement. The experimental apparatus consists of a near-infrared laser diode operating with 4 micro joules pulse energy at 905 nm, a roller pump connected to a silicon plastic tube and a cuvette for circulating the blood sample. In addition, the apparatus comprises a PZT piezoelectric transducer integrated with a battery-powered preamplifier to receive the photoacoustic signal. During the experiment, a glucose solution is mixed into a human blood sample to change its concentration. Although the absorption coefficient of glucose is much smaller than that of blood in the near-infrared region, the osmotic and hydrophilic properties of glucose decrease the reduced scattering coefficient of blood caused by the dissolved glucose surrounding the blood cells. This changes the distribution of the absorbed optical energy in blood, which, in turn, produces a change in the photoacoustic signal. Our experiment demonstrates that signal amplitudes in fresh and stored blood samples in crease about 7% and 10%, respectively, when the glucose concentration reaches the upper limit of the physiological region (500 mg/dl).

Automated Microbiological Detection/Identification System

PubMed Central

Aldridge, C.; Jones, P. W.; Gibson, S.; Lanham, J.; Meyer, M.; Vannest, R.; Charles, R.

1977-01-01

An automated, computerized system, the AutoMicrobic System, has been developed for the detection, enumeration, and identification of bacteria and yeasts in clinical specimens. The biological basis for the system resides in lyophilized, highly selective and specific media enclosed in wells of a disposable plastic cuvette; introduction of a suitable specimen rehydrates and inoculates the media in the wells. An automated optical system monitors, and the computer interprets, changes in the media, with enumeration and identification results automatically obtained in 13 h. Sixteen different selective media were developed and tested with a variety of seeded (simulated) and clinical specimens. The AutoMicrobic System has been extensively tested with urine specimens, using a urine test kit (Identi-Pak) that contains selective media for Escherichia coli, Proteus species, Pseudomonas aeruginosa, Klebsiella-Enterobacter species, Serratia species, Citrobacter freundii, group D enterococci, Staphylococcus aureus, and yeasts (Candida species and Torulopsis glabrata). The system has been tested with 3,370 seeded urine specimens and 1,486 clinical urines. Agreement with simultaneous conventional (manual) cultures, at levels of 70,000 colony-forming units per ml (or more), was 92% or better for seeded specimens; clinical specimens yielded results of 93% or better for all organisms except P. aeruginosa, where agreement was 86%. System expansion in progress includes antibiotic susceptibility testing and compatibility with most types of clinical specimens. Images PMID:334798

Interfacial Force Field Characterization in a Constrained Vapor Bubble Thermosyphon

NASA Technical Reports Server (NTRS)

DasGupta, Sunando; Plawsky, Joel L.; Wayner, Peter C., Jr.

1995-01-01

Isothermal profiles of the extended meniscus in a quartz cuvette were measured in the earth's gravitational field using an image-analyzing interferometer that is based on computer-enhanced video microscopy of the naturally occurring interference fringes. These profiles are a function of the stress field. Experimentally, the augmented Young-Laplace equation is an excellent model for the force field at the solid-liquid-vapor interfaces for heptane and pentane menisci on quartz and tetradecane on SFL6. The effects of refractive indices of the solid and liquid on the measurement techniques were demonstrated. Experimentally obtained values of the disjoining pressure and dispersion constants were compared to those predicted from the Dzyaloshinskii - Lifshitz - Pilaevskii theory for an ideal surface and reasonable agreements were obtained. A parameter introduced gives a quantitative measurement of the closeness of the system to equilibrium. The nonequilibrium behavior of this parameter is also presented

Selective, Specific, and Versatile Personal Biosensors to Organophosphate Chemical Toxins Composed of Polyurethane Immobilized Enzymes

DTIC Science & Technology

2002-01-01

cuvette containing a stir bar and the biosensor. RESULTS ACh ChE Acetate + Choline Betaine aldehyde+H2O2 Choline oxidase O2+ Choline oxidase...O2+ H2O2 Betaine + 2H2O2 carbon electrode electrochemical detection luminol fluorescent adducts visible adducts chemiluminescence fluorescence (CPM...soluble BChE and biosensor BChE at different tem- peratures relative to 30oC. Figure 7. Top: Immobilized choline oxidase and soluble form of the

Easily constructed spectroelectrochemical cell for batch and flow injection analyses.

PubMed

Flowers, Paul A; Maynor, Margaret A; Owens, Donald E

2002-02-01

The design and performance of an easily constructed spectroelectrochemical cell suitable for batch and flow injection measurements are described. The cell is fabricated from a commercially available 5-mm quartz cuvette and employs 60 ppi reticulated vitreous carbon as the working electrode, resulting in a reasonable compromise between optical sensitivity and thin-layer electrochemical behavior. The spectroelectrochemical traits of the cell in both batch and flow modes were evaluated using aqueous ferricyanide and compare favorably to those reported previously for similar cells.

Development of a mercury detection kit based on melamine-functionalized gold nanoparticles.

PubMed

Liu, Guoyan; Ren, Huipeng; Guan, Yuyu; Dai, Ronghua; Chai, Chunyan

2015-01-01

A fast and simple mercury detection kit was developed based on melamine-functionalized gold nanoparticles (GNPs). The detection kit contained reagent 1 (GNPs), reagent 2 (melanine), a reaction cuvette with four separated cells, a colorimetric card and a plastic pipette. The GNPs were prepared by a citrate reduction of HAuCl4. A proper amount of melamine was applied to functionalize the GNPs. The complex reaction took place in the present of Hg(2+) in the test samples, leading to the combination of Hg(2+) with the C=N group of melamine located on the surface of the GNPs. This reaction resulted in damage to the stability of colloid gold, and the aggregation of GNPs occurred. Different color changes (from claret-red to lilac, purple and plum) were displayed with different concentrations of Hg(2+) in the test samples. It was very easy and convenient to determine the amount of mercury ion by the naked eye. The advantages of this methodology are listed as follows: a short detecting time (within 10 min), a high specificity (no significant interference was indicated upon adding a certain amount of Cu(2+), Pb(2+), Zn(2+), Mg(2+), Cd(2+) and Fe(2+)), high sensitivity with a detection limit of 0.01 mg L(-1) , easy operation and practical on-site use.

Spectral analysis of optical emission of microplasma in sea water

NASA Astrophysics Data System (ADS)

Gamaleev, Vladislav; Morita, Hayato; Oh, Jun-Seok; Furuta, Hiroshi; Hatta, Akimitsu

2016-09-01

This work presents an analysis of optical emission spectra from microplasma in three types of liquid, namely artificial sea water composed of 10 typical agents (10ASW), reference solutions each containing a single agent (NaCl, MgCl2 + H2O, Na2SO4, CaCl2, KCl, NaHCO3, KBr, NaHCO3, H3BO3, SrCl2 + H2O, NaF) and naturally sampled deep sea water (DSW). Microplasma was operated using a needle(Pd)-to-plate(Pt) electrode system sunk into each liquid in a quartz cuvette. The radius of the tip of the needle was 50 μm and the gap between the electrodes was set at 20 μm. An inpulse generator circuit, consisting of a MOSFET switch, a capacitor, an inductor and the resistance of the liquid between the electrodes, was used as a pulse current source for operation of discharges. In the spectra, the emission peaks for the main components of sea water and contaminants from the electrodes were detected. Spectra for reference solutions were examined to enable the identification of unassigned peaks in the spectra for sea water. Analysis of the Stark broadening of H α peak was carried out to estimate the electron density of the plasma under various conditions. The characteristics of microplasma discharge in sea water and the analysis of the optical emission spectra will be presented. This work was supported by JSPS KAKENHI Grant Number 26600129.

Measurement of acute toxicity to Mysidopsis bahia using DaphniaQuant{reg_sign} instrument and protocol

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

Blankemeyer, J.T.; Nguyen, T.; Burks, S.L.

1994-12-31

DaphniaQuant{reg_sign} uses a fluorescent dye to permeate the cells of aquatic organisms. The technique has been used on frog embryos, fish embryos, and bovine erythrocytes. Two wavelengths of light are used to excite the fluorescent dye, Di-4-ANEPPS. The blue excitation wavelength measures the cell membrane potential while the yellow excitation wavelength measures the amount of dye loaded into the organisms. The authors applied the technique to the shrimp, Mysidopsis bahia, used in marine toxicity testing. The authors used from 1 to 10 shrimp, loaded into a 3 ml spectrofluorometry plastic cuvette. The fluorescent dye, Di-4-ANEPPS, was mixed with the 3more » ml of ASW in the cuvette at a final Di-4ANEPPS concentration of 10{sub {minus}6} M. After a thirty minute incubation, the fluorescence of Di-4-ANEPPS was measured in the DaphniaQuant{reg_sign} instrument. A similar protocol was used to test various concentrations of standard assay chemicals and effluents. The test chemical was mixed with ASW and Di-4-ANEPPS and incubated with the shrimp for thirty minutes. After thirty minutes, the fluorescence was measured and compared to the fluorescence of the control shrimp. The authors found that the fluorescence from a single shrimp was detectable and gave similar toxicity data as did the replicates using 10 shrimp. They conclude that the DaphniaQuant{reg_sign} assay can be successfully adapted to marine organisms, particularly Mysidopsis bahia.« less

The Lowest Triplet of Tetracyanoquinodimethane via UV-vis Absorption Spectroscopy with Br-Containing Solvents.

PubMed

Khvostenko, Olga G; Kinzyabulatov, Renat R; Khatymova, Laysan Z; Tseplin, Evgeniy E

2017-10-05

This study was undertaken to find the previously unknown lowest triplet of the isolated molecule of tetracyanoquinodimethane (TCNQ), which is a widely used organic semiconductor. The problem is topical because the triplet excitation of this compound is involved in some processes which occur in electronic devices incorporating TCNQ and its derivatives, and information on the TCNQ triplet is needed for better understanding of these processes. The lowest triplet of TCNQ was obtained at 1.96 eV using UV-vis absorption spectroscopy with Br-containing solvents. Production of the triplet band with sufficient intensity in the spectra was provided by the capacity of the Br atom to augment the triplet excitation and through using a 100 mm cuvette. The assignment of the corresponding spectral band to the triplet transition was made by observation that this band appeared only in the spectra recorded in Br-containing solvents but not in spectra recorded in other solvents. Additional support for the triplet assignment came from the overall UV-vis absorption spectra of TCNQ recorded in various solvents, using a 10 mm cuvette, in the 1.38-6.5 eV energy range. Singlet transitions of the neutral TCNQ o molecule and doublet transitions of the TCNQ ¯ negative ion were identified in these overall spectra and were assigned with TD B3LYP/6-31G calculations. Determination of the lowest triplet of TCNQ attained in this work may be useful for theoretical studies and practical applications of this important compound.

Three-dimensional radiation dosimetry based on optically-stimulated luminescence

NASA Astrophysics Data System (ADS)

Sadel, M.; Høye, E. M.; Skyt, P. S.; Muren, L. P.; Petersen, J. B. B.; Balling, P.

2017-05-01

A new approach to three-dimensional (3D) dosimetry based on optically-stimulated luminescence (OSL) is presented. By embedding OSL-active particles into a transparent silicone matrix (PDMS), the well-established dosimetric properties of an OSL material are exploited in a 3D-OSL dosimeter. By investigating prototype dosimeters in standard cuvettes in combination with small test samples for OSL readers, it is shown that a sufficient transparency of the 3D-OSL material can be combined with an OSL response giving an estimated >10.000 detected photons in 1 second per 1mm3 voxel of the dosimeter at a dose of 1 Gy. The dose distribution in the 3D-OSL dosimeters can be directly read out optically without the need for subsequent reconstruction by computational inversion algorithms. The dosimeters carry the advantages known from personal-dosimetry use of OSL: the dose distribution following irradiation can be stored with minimal fading for extended periods of time, and dosimeters are reusable as they can be reset, e.g. by an intense (bleaching) light field.

Flight 1 technical report for experiment 74-37 contained polycrystalline solidification in low-G

NASA Technical Reports Server (NTRS)

Papaziak, J. M.; Kattamis, T. Z.

1976-01-01

A .005 M solution of fluorescein in cyclohexanol was directionally solidified in a standard 10 x 10 x 45mm UV silica cuvette, using a bottom thermoelectric chilling device. Progress of the experiment was monitored by time lapse photography. During flight (SPAR I) the camera malfunctioned and only one quarter of the expected data were collected. Comparison of flight and ground specimens indicated that: (1) The dark green layer observed ahead of the solid-liquid interface which is most likely the solute-enriched zone, appears to be wider in the flight specimen; (2) Parasitic nucleation ahead of the solid-liquid interface in the flight sample led to an irregularly shaped interface, smaller grain size, equiaxed grain morphology and a larger average macroscopic growth rate; (3) The formation of equiaxed grains ahead of the solid-liquid interface in the flight specimen may be attributed to ordered islands within the liquid, which survived remelting because of the low degree of superheating (approximately equal to 1.5 C), did not settle because of reduced gravity and acted as nuclei during cooling.

Phone camera detection of glucose blood level based on magnetic particles entrapped inside bubble wrap.

PubMed

Martinkova, Pavla; Pohanka, Miroslav

2016-12-18

Glucose is an important diagnostic biochemical marker of diabetes but also for organophosphates, carbamates, acetaminophens or salicylates poisoning. Hence, innovation of accurate and fast detection assay is still one of priorities in biomedical research. Glucose sensor based on magnetic particles (MPs) with immobilized enzymes glucose oxidase (GOx) and horseradish peroxidase (HRP) was developed and the GOx catalyzed reaction was visualized by a smart-phone-integrated camera. Exponential decay concentration curve with correlation coefficient 0.997 and with limit of detection 0.4 mmol/l was achieved. Interfering and matrix substances were measured due to possibility of assay influencing and no effect of the tested substances was observed. Spiked plasma samples were also measured and no influence of plasma matrix on the assay was proved. The presented assay showed complying results with reference method (standard spectrophotometry based on enzymes glucose oxidase and peroxidase inside plastic cuvettes) with linear dependence and correlation coefficient 0.999 in concentration range between 0 and 4 mmol/l. On the grounds of measured results, method was considered as highly specific, accurate and fast assay for detection of glucose.

Opportunities for Hydrologic Research in the Congo Basin

NASA Astrophysics Data System (ADS)

Alsdorf, D. E.; Beighley, E., II; Lee, H.; Tshimanga, R.; Spencer, R. G.; O'Loughlin, F.

2014-12-01

We review the published results on the Congo Basin hydrology and find that there are historic data, ongoing measurement recording efforts, and important model results. Annual rainfall is ~2000 mm/yr along an east-west trend, decreasing northward and southward to ~1100 mm/yr. While some studies show rain gauges at specific locations with declines in P greater than 10% from 1960 to 1990, other studies suggest that basin wide decreases from 1951 to 1993 are modest at 4.5% or that the trend is minimal. Studies during the 1950s using lysimeters, pans, and models suggest that the annual potential ET varies little across the basin at a 1100 mm/yr to 1200 mm/yr. Over the past century, river discharge data has been collected at 100s of stream gauges with historic and recent data at 96 locations now publicly available. Discharge of the Congo River at Kinshasa-Brazzaville experienced an increase of 21% during 1960-1970 in comparison to background values of the previous decades and of today. There does not appear to be a long-term discharge trend over the century of record. Satellite altimetry measurements collected during high and low flows show that the Cuvette Centrale wetland water levels are consistently 0.5m to 3m higher in elevation than the immediately adjacent Congo River levels. Wetland water depths are shallow at about 1m whereas the Congo is typically less than 15m deep everywhere upstream of Kinshasa. The wetlands do not appear to be marked by sizable channels such that the flows are diffusive. CO2 and CH4 evasion from the Congo waters directly to the atmosphere are estimated at 1.6 to 3.2 Tg/yr for CH4 from the Cuvette wetland waters and 105 to 204 g C/m2/yr for CO2 from waters of the Oubangui River. Using these published results, we suggest seven hypotheses that may lead to important water and carbon cycle discoveries. These hypotheses focus on the source of the Cuvette waters and how those waters leave the wetland; on river discharge generated by historic rainfall; on the connection between climate change and the rainfall-runoff generated by the ITCZ; on deforestation and hydroelectric power generation; and on the amount of carbon emitted from Congo waters. To address these hypotheses, the Congo research community will need to work together to host meetings, share ideas, access data, ensure funding, and provide infrastructural support.

Introduction to Solid Supported Membrane Based Electrophysiology

PubMed Central

Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

2013-01-01

The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods. PMID:23711952

Introduction to solid supported membrane based electrophysiology.

PubMed

Bazzone, Andre; Costa, Wagner Steuer; Braner, Markus; Călinescu, Octavian; Hatahet, Lina; Fendler, Klaus

2013-05-11

The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire. After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage. The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis. This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods.

Modification of primordial ices by cosmic rays as simulated by cyclotron irradiation

NASA Technical Reports Server (NTRS)

Kaiser, R. I.; Roessler, K.

1992-01-01

Frozen CH4 and CH4/Ar mixtures closed into metal cuvettes and open to the vacuum were irradiated at 15 and 77 K with 10 - 20 MeV p and He-3(2+) ions in order to simulate the effect of cosmic rays on solid organic matter in space. Ices exposed to vacuum represent surfaces of icy systems whereas closed systems stand for bulk ices. The products were analyzed by MS, SEM, RBS, ERDA, H-1-NMR, HPLC, GC-MS, NEXAFS, and FT-IR. Volatile products consisted of a mixture of low molecular species, e.g., C2H2, C2H4, C2H6, and long linear aliphatic and olefinic compounds. The formation of polycyclic aromatic hydrocarbons (PAH's) and related species in solid CH4 is due to a multi-center reaction within one collision cascade and is governed by energy density effects with critical linear energy transfer values L(sub T) between 2 and 10 keV/micron. Open ices exhibit preferential hydrogen release resulting in an increased carbonization as compared to more hydrogen rich molecules protected inside large icy bodies.

High-performance coaxial EPR cavity for investigations at elevated temperatures and pressures

NASA Astrophysics Data System (ADS)

Goldberg, Ira B.; McKinney, Ted M.

1984-07-01

A microwave cavity suitable for heating a sample to temperatures above 800 °C within 15 s at gas pressures above 17.5 MPa is reported. The cavity is coaxial and operates in the TE011 mode at frequencies between 9 and 10 GHz. The heating element is constructed of nickel-chromium (i.e., Chromel) wire. It consists of two concentric helices wound in opposite senses (directions) and connected in series so as to minimize the magnetic field generated by the heater current. The heater is potted in magnesium oxide-phosphate ceramic and placed inside of a cylinder made from 50-μm copper foil which provides uniform temperature distribution and shields the heater from the microwave field. This assembly then serves as the heating element and the coaxial conductor of the cavity. The diameter of the coaxial heater assembly is approximately 7 mm. The sample is confined by a cylindrical quartz cuvette which surrounds the coaxial conductor. Sample thicknesses of 0.2 to 1.0 mm can be used. Heating from room temperature to 800 °C requires between 15 and 20 s. Operating pressures up to 17 MPa have been used, although the structural design limit of the brass or beryllium copper walls is greater than 22 MPa. Modulation coils are placed in recessed areas of the cavity walls and covered with a thin layer of copper. Cooling water flows through channels cut into the walls to maintain constant microwave parameters. Q factors of 8000 -12 000 can be obtained depending on the sample.

Measuring high spectral resolution specific absorption coefficients for use with hyperspectral imagery

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

Keller, M.; Bostater, C.

1997-06-01

A portable, long path length (50 cm), flow through, absorption tube system is utilized to obtain in-situ specific absorption coefficients from various water environments consisting of both clear and turbid water conditions from an underway ship or vessel. The high spectral resolution absorption signatures can be obtained and correlated with measured water quality parameters along a ship track. The long path cuvette system is capable of measuring important water quality parameters such as chlorophyll-a, seston or total suspended matter, tannins, humics, fulvic acids, or dissolved organic matter (dissolved organic carbon, DOC). The various concentrations of these substances can be determinedmore » and correlated with laboratory measurements using the double inflection ratio (DIR) of the spectra based upon derivative spectroscopy. The DIR is determined for all of the possible combinations of the bands ranging from 362-1115 nm using 252 channels, as described previously by Bostater. The information gathered from this system can be utilized in conjunction with hyperspectral imagery that allows one to relate reflectance and absorption to water quality of a particular environment. A comparison is made between absorption signatures and reflectance obtained from the Banana River, Florida.« less

Techniques used for the screening of hemoglobin levels in blood donors: current insights and future directions.

PubMed

Chaudhary, Rajendra; Dubey, Anju; Sonker, Atul

2017-01-01

Blood donor hemoglobin (Hb) estimation is an important donation test that is performed prior to blood donation. It serves the dual purpose of protecting the donors' health against anemia and ensuring good quality of blood components, which has an implication on recipients' health. Diverse cutoff criteria have been defined world over depending on population characteristics; however, no testing methodology and sample requirement have been specified for Hb screening. Besides the technique, there are several physiological and methodological factors that affect accuracy and reliability of Hb estimation. These include the anatomical source of blood sample, posture of the donor, timing of sample and several other biological factors. Qualitative copper sulfate gravimetric method has been the archaic time-tested method that is still used in resource-constrained settings. Portable hemoglobinometers are modern quantitative devices that have been further modified to reagent-free cuvettes. Furthermore, noninvasive spectrophotometry was introduced, mitigating pain to blood donor and eliminating risk of infection. Notwithstanding a tremendous evolution in terms of ease of operation, accuracy, mobility, rapidity and cost, a component of inherent variability persists, which may partly be attributed to pre-analytical variables. Hence, blood centers should pay due attention to validation of test methodology, competency of operating staff and regular proficiency testing of the outputs. In this article, we have reviewed various regulatory guidelines, described the variables that affect the measurements and compared the validated technologies for Hb screening of blood donors along with enumeration of their merits and limitations.

Stabilization of Z-RNA under Physiological Conditions and Recognition by Anti-Z DNA Antibodies.

DTIC Science & Technology

1987-01-01

Raising the ionic strength to 6 M NaBr or NaCIO 4 results in a transition in Br-poly[r(C-G)] to a Z-RNA (ZR) conformation as judged by CD spectroscopy . At... cytidine residues in Br-poly[[r(C-G)] were brominated. The extinction coefficient for Br-poly[r(C-G)] was taken as 5770 M- 1 cmŕ. CD. absorbance and...Raman scattering spectroscopy . CD spectra were recorded on a JASCO J500C spectropolarimeter in 1 cm pathlength quartz cuvettes surrounded by a

An evaluation of patient self-testing competency of prothrombin time for managing anticoagulation: pre-randomization results of VA Cooperative Study #481--The Home INR Study (THINRS).

PubMed

Dolor, Rowena J; Ruybalid, R Lynne; Uyeda, Lauren; Edson, Robert G; Phibbs, Ciaran; Vertrees, Julia E; Shih, Mei-Chiung; Jacobson, Alan K; Matchar, David B

2010-10-01

Prior studies suggest patient self-testing (PST) of prothrombin time (PT) can improve the quality of anticoagulation (AC) and reduce complications (e.g., bleeding and thromboembolic events). "The Home INR Study" (THINRS) compared AC management with frequent PST using a home monitoring device to high-quality AC management (HQACM) with clinic-based monitoring on major health outcomes. A key clinical and policy question is whether and which patients can successfully use such devices. We report the results of Part 1 of THINRS in which patients and caregivers were evaluated for their ability to perform PST. Study-eligible patients (n = 3643) were trained to use the home monitoring device and evaluated after 2-4 weeks for PST competency. Information about demographics, medical history, warfarin use, medications, plus measures of numeracy, literacy, cognition, dexterity, and satisfaction with AC were collected. Approximately 80% (2931 of 3643) of patients trained on PST demonstrated competency; of these, 8% (238) required caregiver assistance. Testers who were not competent to perform PST had higher numbers of practice attempts, higher cuvette wastage, and were less able to perform a fingerstick or obtain blood for the cuvette in a timely fashion. Factors associated with failure to pass PST training included increased age, previous stroke history, poor cognition, and poor manual dexterity. A majority of patients were able to perform PST. Successful home monitoring of PT with a PST device required adequate levels of cognition and manual dexterity. Training a caregiver modestly increased the proportion of patients who can perform PST.

Determination of phosphate in soil extracts in the field: A green chemistry enzymatic method.

PubMed

Campbell, Ellen R; Warsko, Kayla; Davidson, Anna-Marie; Bill Campbell, Wilbur H

2015-01-01

Measurement of ortho-phosphate in soil extracts usually involves sending dried samples of soil to a laboratory for analysis and waiting several weeks for the results. Phosphate determination methods often involve use of strong acids, heavy metals, and organic dyes. To overcome limitations of this approach, we have developed a phosphate determination method which can be carried out in the field to obtain results on the spot. This new method uses: •Small volumes.•An enzymatic reaction.•Green chemistry. First, the soil sample is extracted with deionized water and filtered. Next, an aliquot of the soil extract (0.5 mL) is transferred to a disposable cuvette, containing 0.5 mL of reaction mixture [200 mM HEPES, pH 7.6, 20 mM MgCl2, with 80 nmol 2-amino-6-mercapto-7-methylpurine ribonucleoside (MESG) and 1 unit of recombinant purine nucleoside phosphorylase (PNP; EC 2.4.2.1)], mixed, and incubated for 10 min at field temperature. Absorbance of the completed reaction is measured at 360 nm in open-source, portable photometer linked by bluetooth to a smartphone. The phosphate and phosphorus content of the soil is determined by comparison of its absorbance at 360 nm to a previously prepared standard phosphate curve, which is stored in the smartphone app.

Determination of phosphate in soil extracts in the field: A green chemistry enzymatic method

PubMed Central

Campbell, Ellen R.; Warsko, Kayla; Davidson, Anna-Marie; (Bill) Campbell, Wilbur H.

2015-01-01

Measurement of ortho-phosphate in soil extracts usually involves sending dried samples of soil to a laboratory for analysis and waiting several weeks for the results. Phosphate determination methods often involve use of strong acids, heavy metals, and organic dyes. To overcome limitations of this approach, we have developed a phosphate determination method which can be carried out in the field to obtain results on the spot. This new method uses: • Small volumes. • An enzymatic reaction. • Green chemistry. First, the soil sample is extracted with deionized water and filtered. Next, an aliquot of the soil extract (0.5 mL) is transferred to a disposable cuvette, containing 0.5 mL of reaction mixture [200 mM HEPES, pH 7.6, 20 mM MgCl2, with 80 nmol 2-amino-6-mercapto-7-methylpurine ribonucleoside (MESG) and 1 unit of recombinant purine nucleoside phosphorylase (PNP; EC 2.4.2.1)], mixed, and incubated for 10 min at field temperature. Absorbance of the completed reaction is measured at 360 nm in open-source, portable photometer linked by bluetooth to a smartphone. The phosphate and phosphorus content of the soil is determined by comparison of its absorbance at 360 nm to a previously prepared standard phosphate curve, which is stored in the smartphone app. PMID:26150991

Discrimination of several Indonesian specialty coffees using Fluorescence Spectroscopy combined with SIMCA method

NASA Astrophysics Data System (ADS)

Suhandy, D.; Yulia, M.

2018-03-01

Indonesia is one of the important producers of several specialty coffees, which have a particularly high economic value, including Civet coffee (‘kopi luwak’ in Indonesian language) and Peaberry coffee (‘kopi lanang’ in Indonesian language). The production of Civet and Peaberry coffee is very limited. In order to provide authentication of Civet and Peaberry coffee and protect consumers from adulteration, a robust and easy method for evaluating ground Civet and Peaberry coffee and detection of its adulteration is needed. In this study, we investigate the use of fluorescence spectroscopy combined with SIMCA (soft independent modelling of class analogies) method to discriminate three Indonesian specialty coffee: ground Peaberry, Civet and Pagar Alam coffee. Total 90 samples were used (30 samples for Civet, Peaberry and Pagar Alam coffee, respectively). All coffee samples were ground using a home-coffee-grinder. Since particle size in coffee powder has a significant influence on the spectra obtained, we sieved all coffee samples through a nest of U. S. standard sieves (mesh number of 40) on a Meinzer II sieve shaker for 10 minutes to obtain a particle size of 420 µm. The experiments were performed at room temperature (around 27-29°C). All samples were extracted with distilled water and then filtered. For each samples, 3 mL of extracted sample then was pipetted into 10 mm cuvettes for spectral data acquisition. The EEM (excitation-emission matrix) spectral data of coffee samples were acquired using JASCO FP-8300 Fluorescence Spectrometer. The principal component analysis (PCA) result shows that it is possible to discriminate types of coffee based on information from EEM (excitation-emission matrix) spectral data. Using SIMCA method, the discrimination model of Indonesian specialty coffee was successfully developed and resulted in high performance of discrimination with 100% of sensitivity and specificity for Peaberry, Civet and Pagar Alam coffee. This research has opened the possibility to develop a promising method to detect and evaluate authentication of Indonesian specialty coffees using fluorescence spectroscopy.

How feasible is remote 3D dosimetry for MR guided Radiation Therapy (MRgRT)?

NASA Astrophysics Data System (ADS)

Mein, S.; Rankine, L.; Miles, D.; Juang, T.; Cai, B.; Curcuru, A.; Mutic, S.; Fenoli, J.; Adamovics, J.; Li, H.; Oldham, M.

2017-05-01

To develop and apply a remote dosimetry protocol with PRESAGE® radiochromic plastic and optical-CT readout in the validation of MRI guided radiation therapy (MRgRT) treatments (MRIdian® by ViewRay®). Through multi-institutional collaboration we performed PRESAGE® dosimetry studies in 4ml cuvettes to investigate dose-response linearity, MR-compatibility, and energy-independence. An open calibration field and symmetrical 3-field plans were delivered to 10cm diameter PRESAGE® to examine percent depth dose and response uniformity under a magnetic field. Evidence of non-linear dose response led to a large volume PRESAGE® study where small corrections were developed for temporally- and spatially-dependent behaviors observed between irradiation and delayed readout. TG-119 plans were created in the MRIdian® TPS and then delivered to 14.5cm 2kg PRESAGE® dosimeters. Through the domestic investigation of an off-site MRgRT system, a refined 3D remote dosimetry protocol is presented capable of validation of advanced MRgRT radiation treatments.

Measurements of volatile organic compounds emitted from plants in the metropolitan area of São Paulo City , Brazil.

NASA Astrophysics Data System (ADS)

Carvalho, L.; Pisani, S.; Pool, C.; Vasconcellos, P.

2003-04-01

The presence of the biogenic hydrocarbons in an NO_x-containing atmosphere can enhance ozone generation and the impact of volatile organic compounds (VOCs) emitted from vegetation on atmospheric chemistry has been investigated. No study of VOC emission rates from plant species has been carried out in São Paulo City, Brazil, prior to this work. This study is part of a three-years project on biogenic volatile organic compounds emissions from species of plants found in the vegetation of the São Paulo metropolitan area. Typical plants (Alchornea sidifolia, Cupania oblongifolia, Cecropia pachystachia, Casearia sylvestris, Machaerium villosum, Croton floribundus, Myrcia rostrata, Solanum erianthum and Ficus insípida) were selected and identical species were studied in urban, sub-urban and forest regions. Biogenic hydrocarbons were determined placing branches of plants in enclosures and measuring the accumulation of emitted compounds in an all-Teflon chamber, the cuvette system. Measuring ambient VOC concentration adsorptive preconcentration, followed by GC-MS after thermal desorption of the sample, was employed to determine components heavier than C_5. Collection of carbonyl compounds on 2, 4-dinitrophenylhydrazine coated particles followed by HPLC-UV was used to analyze low molecular weight carbonyl compounds. Emissions rates of isoprene, a-pinene, camphene and limonene ranged from 0.01 to 2.16 μg C/h.g and emissions rates of aldehydes (C_1 - C_6), acrolein, methacrolein, 2-butanone and acetone ranged from 0.04 to 4.20 μg C/h.g. Ambient and chamber temperatures, relative humidity, light intensity, O_3 and NO_x were monitored during experiments.

Optical immunosensors for detection of Listeria monocytogenes and Salmonella enteritidis from food

NASA Astrophysics Data System (ADS)

Bhunia, Arun K.; Geng, Tao; Lathrop, Amanda; Valadez, Angela; Morgan, Mark T.

2004-03-01

Listeria monocytogenes and Salmonella are two major foodborne pathogens of significant concern. Two optical evanescent wave immunosensors were evaluated for detection: Antibody-coupled fiber-optic biosensor and a surface plasmon resonant (SPR) immunosensor. In the fiber-optic sensor, polyclonal antibodies for the test organisms were immobilized on polystyrene fiber wave -guides using streptavidin - biotin chemistry. Cyanine 5 -labeled monoclonal antibodies C11E9 (for L. monocytogenes) and SF-11 (for Salmonella Enteritidis) were used to generate a specific fluorescent signal. Signal acquisition was performed by launching a laser-light (635 nm) from an Analyte-2000. This immunosensor was able to detect 103 - 109 cfu/ml of L. monocytogenes or 106-109 cfu/ml of Salmonella Enteritidis and the assays were conducted at near real-time with results obtained within one hour of sampling. The assays were specific and showed signal even in the presence of other microorganisms such as E. coli, Enterococcus faecalis or Salmonella Typhimurium. In the SPR system, IAsys instrument (resonant mirror sensor) was used. Monoclonal antibody-C11E9 was directly immobilized onto a carboxylate cuvette. Whole Listeria cells at various concentrations did not yield any signal while surface protein extracts did. Crude protein extracts from L. monocytogenes and L. innocua had average binding responses of around 150 arc sec (0.25 ng/mm2), which was significantly different from L. grayi, L. ivanovii, or L. welshimeri with average responses of <48 arc sec. Both fiber-optic and SPR sensors show promise in near real-time detection of foodborne L. monocytogenes and Salmonella Enteritidis.

Application of dynamic light scattering for studying the evolution of micro- and nano-droplets

NASA Astrophysics Data System (ADS)

Derkachov, G.; Jakubczyk, D.; Kolwas, K.; Shopa, Y.; Woźniak, M.; Wojciechowski, T.

2018-01-01

The dynamic light scattering (DLS) technique was used for studying the processes of aggregation of spherical SiO2 particles in various diethylene glycol (DEG) suspensions. The suspensions were studied in a cuvette, in a millimeter-sized droplet and in a micrometer-sized droplet. For the first time DLS signals for droplets of picolitre volume, levitated in an electrodynamic quadrupole trap, were obtained. It is shown that the correlation analysis of light scattered from a micro-droplet allows monitoring the changes of its internal structure, as well as its motions: trap-constricted Brownian motions and random rotations.

Photoacoustic imaging of fluorophores using pump-probe excitation

PubMed Central

Märk, Julia; Schmitt, Franz-Josef; Theiss, Christoph; Dortay, Hakan; Friedrich, Thomas; Laufer, Jan

2015-01-01

A pump-probe technique for the detection of fluorophores in tomographic PA images is introduced. It is based on inducing stimulated emission in fluorescent molecules, which in turn modulates the amount of thermalized energy, and hence the PA signal amplitude. A theoretical model of the PA signal generation in fluorophores is presented and experimentally validated on cuvette measurements made in solutions of Rhodamine 6G, a fluorophore of known optical and molecular properties. The application of this technique to deep tissue tomographic PA imaging is demonstrated by determining the spatial distribution of a near-infrared fluorophore in a tissue phantom. PMID:26203378

Ozone fumigation under dark/light conditions of Norway Spruce (Picea Abies) and Scots Pine (Pinus Sylvestris)

NASA Astrophysics Data System (ADS)

Canaval, Eva; Jud, Werner; Hansel, Armin

2015-04-01

Norway Spruce (Picea abies) and Scots Pine (Pinus sylvestris) represent dominating tree species in the northern hemisphere. Thus, the understanding of their ozone sensitivity in the light of the expected increasing ozone levels in the future is of great importance. In our experiments we investigated the emissions of volatile organic compounds (VOCs) of 3-4 year old Norway Spruce and Scots Pine seedlings under ozone fumigation (50-150 ppbv) and dark/light conditions. For the experiments the plants were placed in a setup with inert materials including a glass cuvette equipped with a turbulent air inlet and sensors for monitoring a large range of meteorological parameters. Typical conditions were 20-25°C and a relative humidity of 70-90 % for both plant species. A fast gas exchange rate was used to minimize reactions of ozone in the gas phase. A Switchable-Reagent-Ion-Time-of-Flight-MS (SRI-ToF-MS) was used to analyze the VOCs at the cuvette outlet in real-time during changing ozone and light levels. The use of H3O+ and NO+ as reagent ions allows the separation of certain isomers (e.g. aldehydes and ketones) due to different reaction pathways depending on the functional groups of the molecules. Within the Picea abies experiments the ozone loss, defined as the difference of the ozone concentration between cuvette inlet and outlet, remained nearly constant at the transition from dark to light. This indicates that a major part of the supplied ozone is depleted non-stomatally. In contrast the ozone loss increased by 50 % at the transition from dark to light conditions within Pinus sylvestris experiments. In this case the stomata represent the dominant loss channel. Since maximally 0.1% of the ozone loss could be explained by gas phase reactions with monoterpenes and sesquiterpenes, we suggest that ozone reactions on the surface of Picea abies represent the major sink in this case and lead to an light-independent ozone loss. This is supported by the fact that we detected a broad range of unidentified oxygenated ozonolysis products and their fragments, whose amount exceed by far the detected loss of BVOCs under ozone exposure. However, the observed products are not attributable to neither green leaf volatiles nor to other known volatile precursors. Furthermore Picea abies emits a smaller amount of ozone induced green leaf volatiles than Pinus sylvestris. Based on this results we can explain the higher ozone tolerance of Picea abies, which has been observed before. A likely reason for the differences in stomatal and surface ozone loss on the investigated plants are differences in the amount and kind of unsaturated semi-volatile compounds on the needle surface.

Simultaneous determination of glucose, triglycerides, urea, cholesterol, albumin and total protein in human plasma by Fourier transform infrared spectroscopy: direct clinical biochemistry without reagents.

PubMed

Jessen, Torben E; Höskuldsson, Agnar T; Bjerrum, Poul J; Verder, Henrik; Sørensen, Lars; Bratholm, Palle S; Christensen, Bo; Jensen, Lene S; Jensen, Maria A B

2014-09-01

Direct measurement of chemical constituents in complex biologic matrices without the use of analyte specific reagents could be a step forward toward the simplification of clinical biochemistry. Problems related to reagents such as production errors, improper handling, and lot-to-lot variations would be eliminated as well as errors occurring during assay execution. We describe and validate a reagent free method for direct measurement of six analytes in human plasma based on Fourier-transform infrared spectroscopy (FTIR). Blood plasma is analyzed without any sample preparation. FTIR spectrum of the raw plasma is recorded in a sampling cuvette specially designed for measurement of aqueous solutions. For each analyte, a mathematical calibration process is performed by a stepwise selection of wavelengths giving the optimal least-squares correlation between the measured FTIR signal and the analyte concentration measured by conventional clinical reference methods. The developed calibration algorithms are subsequently evaluated for their capability to predict the concentration of the six analytes in blinded patient samples. The correlation between the six FTIR methods and corresponding reference methods were 0.87

Annual net primary productivity of a cyanobacteria-dominated biological soil crust in the Gulf Savannah, Queensland, Australia

NASA Astrophysics Data System (ADS)

Büdel, Burkhard; Williams, Wendy J.; Reichenberger, Hans

2018-01-01

Biological soil crusts (biocrusts) are a common element of the Queensland (Australia) dry savannah ecosystem and are composed of cyanobacteria, algae, lichens, bryophytes, fungi and heterotrophic bacteria. Here we report how the CO2 gas exchange of the cyanobacteria-dominated biocrust type from Boodjamulla National Park in the north Queensland Gulf Savannah responds to the pronounced climatic seasonality and on their quality as a carbon sink using a semi-automatic cuvette system. The dominant cyanobacteria are the filamentous species Symplocastrum purpurascens together with Scytonema sp. Metabolic activity was recorded between 1 July 2010 and 30 June 2011, during which CO2 exchange was only evident from November 2010 until mid-April 2011, representative of 23.6 % of the 1-year recording period. In November at the onset of the wet season, the first month (November) and the last month (April) of activity had pronounced respiratory loss of CO2. The metabolic active period accounted for 25 % of the wet season and of that period 48.6 % was net photosynthesis (NP) and 51.4 % dark respiration (DR). During the time of NP, net photosynthetic uptake of CO2 during daylight hours was reduced by 32.6 % due to water supersaturation. In total, the biocrust fixed 229.09 mmol CO2 m-2 yr-1, corresponding to an annual carbon gain of 2.75 g m-2 yr-1. Due to malfunction of the automatic cuvette system, data from September and October 2010 together with some days in November and December 2010 could not be analysed for NP and DR. Based on climatic and gas exchange data from November 2010, an estimated loss of 88 mmol CO2 m-2 was found for the 2 months, resulting in corrected annual rates of 143.1 mmol CO2 m-2 yr-1, equivalent to a carbon gain of 1.7 g m-2 yr-1. The bulk of the net photosynthetic activity occurred above a relative humidity of 42 %, indicating a suitable climatic combination of temperature, water availability and light intensity well above 200 µmol photons m-2 s-1 photosynthetic active radiation. The Boodjamulla biocrust exhibited high seasonal variability in CO2 gas exchange pattern, clearly divided into metabolically inactive winter months and active summer months. The metabolic active period commences with a period (of up to 3 months) of carbon loss, likely due to reestablishment of the crust structure and restoration of NP prior to about a 4-month period of net carbon gain. In the Gulf Savannah biocrust system, seasonality over the year investigated showed that only a minority of the year is actually suitable for biocrust growth and thus has a small window for potential contribution to soil organic matter.

Assessment of volatile organic compound emissions from ecosystems of China

NASA Astrophysics Data System (ADS)

Klinger, L. F.; Li, Q.-J.; Guenther, A. B.; Greenberg, J. P.; Baker, B.; Bai, J.-H.

2002-11-01

Isoprene, monoterpene, and other volatile organic compound (VOC) emissions from grasslands, shrublands, forests, and peatlands in China were characterized to estimate their regional magnitudes and to compare these emissions with those from landscapes of North America, Europe, and Africa. Ecological and VOC emission sampling was conducted at 52 sites centered in and around major research stations located in seven different regions of China: Inner Mongolia (temperate), Changbai Mountain (boreal-temperate), Beijing Mountain (temperate), Dinghu Mountain (subtropical), Ailao Mountain (subtropical), Kunming (subtropical), and Xishuangbanna (tropical). Transects were used to sample plant species and growth form composition, leafy (green) biomass, and leaf area in forests representing nearly all the major forest types of China. Leafy biomass was determined using generic algorithms based on tree diameter, canopy structure, and absolute cover. Measurements of VOC emissions were made on 386 of the 541 recorded species using a portable photo-ionization detector method. For 105 species, VOC emissions were also measured using a flow-through leaf cuvette sampling/gas chromatography analysis method. Results indicate that isoprene and monoterpene emissions, as well as leafy biomass, vary systematically along gradients of ecological succession in the same manner found in previous studies in the United States, Canada, and Africa. Applying these results to a regional VOC emissions model, we arrive at a value of 21 Tg C for total annual biogenic VOC emissions from China, compared to 5 Tg C of VOCs released annually from anthropogenic sources there. The isoprene and monoterpene emissions are nearly the same as those reported for Europe, which is comparable in size to China.

Time-dependent inhibition by glyceryl trinitrate of platelet aggregation caused by U46619 (a thromboxane/endoperoxide receptor agonist).

PubMed Central

Kampf, G; Ritter, J M

1994-01-01

Glyceryl trinitrate is a weak inhibitor of platelet aggregation in vitro. Its effect on platelet aggregation in response to U46619 (a thromboxane/endoperoxide receptor agonist) was studied turbidometrically in platelet-rich plasma from healthy volunteers. The object was to determine whether inhibition was influenced by a period of preincubation between preparation of platelet-rich plasma and addition of glyceryl trinitrate. Incubation was performed at 37 degrees C and 22 degrees C. Samples were removed at intervals and transferred to an aggregometer cuvette at 37 degrees C. Glyceryl trinitrate (100 microM) or an equal volume of distilled water was added 5 min before U46619 (2 microM), and aggregation recorded as change in light transmission. Inhibition by glyceryl trinitrate was markedly time and temperature dependent, with a progressive increase in inhibitory potency between 120 and 300 min preincubation at 37 degrees C but not at 22 degrees C. The explanation of this is unknown but the effect was not influenced by lipopolysaccharide or by cycloheximide, so it does not appear to be due to exposure to endotoxin or to enzyme induction in vitro. PMID:7946941

Isotopic composition of transpiration and rates of change in leaf water isotopologue storage in response to environmental variables.

PubMed

Simonin, Kevin A; Roddy, Adam B; Link, Percy; Apodaca, Randy; Tu, Kevin P; Hu, Jia; Dawson, Todd E; Barbour, Margaret M

2013-12-01

During daylight hours, the isotope composition of leaf water generally approximates steady-state leaf water isotope enrichment model predictions. However, until very recently there was little direct confirmation that isotopic steady-state (ISS) transpiration in fact exists. Using isotope ratio infrared spectroscopy (IRIS) and leaf gas exchange systems we evaluated the isotope composition of transpiration and the rate of change in leaf water isotopologue storage (isostorage) when leaves were exposed to variable environments. In doing so, we developed a method for controlling the absolute humidity entering the gas exchange cuvette for a wide range of concentrations without changing the isotope composition of water vapour. The measurement system allowed estimation of (18)O enrichment both at the evaporation site and for bulk leaf water, in the steady state and the non-steady state. We show that non-steady-state effects dominate the transpiration isoflux even when leaves are at physiological steady state. Our results suggest that a variable environment likely prevents ISS transpiration from being achieved and that this effect may be exacerbated by lengthy leaf water turnover times due to high leaf water contents. © 2013 John Wiley & Sons Ltd.

Measurement of gross photosynthesis, respiration in the light and mesophyll conductance in leaves using H218O labeling and high precision isotope ratio mass spectrometry

NASA Astrophysics Data System (ADS)

Griffin, K. L.; Gauthier, P. P.; Battle, M. O.; Bender, M. L.

2016-12-01

A fundamental challenge in plant physiology is independently determining the rates of gross O2 production by photosynthesis and O2 consumption by respiration, photorespiration, and other processes. Previous studies on isolated chloroplasts or leaves have separately constrained net and gross O2 production (NOP and GOP, respectively) by labeling ambient O2 with 18O while leaf water was unlabeled. Here, we introduce a new method to accurately measure GOP and NOP of whole detached leaves in a cuvette as a routine gas exchange measurement. The petiole is immersed in water enriched to a δ18O of 10,000‰, and the leaf is labeled through the transpiration stream. GOP is calculated from the increase in δ18O of O2 as air passes through the cuvette. NOP is determined from the increase in O2/N2. Both terms are measured by isotope ratio mass spectrometry. CO2 assimilation and other standard gas exchange parameters are also measured. Reproducible measurements are made on a single leaf for up to 15 hours. By investigating the light response curve of NOP and GOP in Phaseolus vulgaris, we found that respiration is inhibited in the light (Kok effect) when [O2]=21% but not when [O2]=2%. The ratio of NOP to net CO2 assimilation was 1.03 ± 0.01 for all leaves studied. Additionally, using GOP as a constraint, we determined chloroplastic [CO2], and we found that mesophyll conductance increases with light intensity. An extensive list of gas exchange properties is measured with this O2 method, making it a unique tool to study and understand leaf physiological traits and the biogeochemistry of carbon cycling.

Measurement of Gross Photosynthesis, Respiration in the Light, and Mesophyll Conductance Using H218O Labeling1[OPEN

PubMed Central

Battle, Mark O.; Griffin, Kevin L.; Bender, Michael L.

2018-01-01

A fundamental challenge in plant physiology is independently determining the rates of gross O2 production by photosynthesis and O2 consumption by respiration, photorespiration, and other processes. Previous studies on isolated chloroplasts or leaves have separately constrained net and gross O2 production (NOP and GOP, respectively) by labeling ambient O2 with 18O while leaf water was unlabeled. Here, we describe a method to accurately measure GOP and NOP of whole detached leaves in a cuvette as a routine gas-exchange measurement. The petiole is immersed in water enriched to a δ18O of ∼9,000‰, and leaf water is labeled through the transpiration stream. Photosynthesis transfers 18O from H2O to O2. GOP is calculated from the increase in δ18O of O2 as air passes through the cuvette. NOP is determined from the increase in O2/N2. Both terms are measured by isotope ratio mass spectrometry. CO2 assimilation and other standard gas-exchange parameters also were measured. Reproducible measurements are made on a single leaf for more than 15 h. We used this method to measure the light response curve of NOP and GOP in French bean (Phaseolus vulgaris) at 21% and 2% O2. We then used these data to examine the O2/CO2 ratio of net photosynthesis, the light response curve of mesophyll conductance, and the apparent inhibition of respiration in the light (Kok effect) at both oxygen levels. The results are discussed in the context of evaluating the technique as a tool to study and understand leaf physiological traits. PMID:29588336

Comparison of a Resonant Mirror Biosensor (IAsys) and a Quartz Crystal Microbalance (QCM) for the Study on Interaction between Paeoniae Radix 801 and Endothelin-1.

PubMed

Huang, Jiadong; Lin, Qing; Yu, Jinghua; Ge, Shenguang; Li, Jing; Yu, Min; Zhao, Zixia; Wang, Xinsheng; Zhang, Xiuming; He, Xiaorui; Yuan, Liang; Yin, Huijun; Osa, Tetsuo; Chen, Keji; Chen, Qiang

2008-12-15

A resonant mirror biosensor, IAsys, and a quartz crystal microbalance (QCM) are known independently as surface sensitive analytical devices capable of label-free and in situ bioassays. In this study, an IAsys and a QCM are employed for a new study on the action mechanism of Paeoniae Radix 801 (P. radix 801) by detecting the specific interaction between P. radix 801 and endothelin-1 (ET-1). In the experiments, ET-1 was immobilized on the surfaces of the IAsys cuvette and the QCM substrate by surface modification techniques, and then P. radix 801 solution was contacted to the cuvette and the substrate, separately. Then, the binding and interaction process between P. radix 801 and ET-1 was monitored by IAsys and QCM, respectively. The experimental results showed that P. radix 801 binds ET-1 specifically. The IAsys and QCM response curves to the ET-1 immobilization and P. radix 801 binding are similar in reaction process, but different in binding profiles, reflecting different resonation principles. Although both IAsys and QCM could detect the interaction of P. radix 801 and ET-1 with high reproducibility and reliability through optimization of the ET-1 coating, the reproducibility and reliability obtained by IAsys are better than those obtained by QCM, since the QCM frequency is more sensitive to temperature fluctuations, atmospheric changes and mechanical disturbances. However, IAsys and QCM are generally potent and reliable tools to study the interaction of P. radix 801 and ET-1, and can conclusively be applied to the action mechanism of P. radix 801.

Quantitative locomotion study of freely swimming micro-organisms using laser diffraction.

PubMed

Magnes, Jenny; Susman, Kathleen; Eells, Rebecca

2012-10-25

Soil and aquatic microscopic organisms live and behave in a complex three-dimensional environment. Most studies of microscopic organism behavior, in contrast, have been conducted using microscope-based approaches, which limit the movement and behavior to a narrow, nearly two-dimensional focal field.(1) We present a novel analytical approach that provides real-time analysis of freely swimming C. elegans in a cuvette without dependence on microscope-based equipment. This approach consists of tracking the temporal periodicity of diffraction patterns generated by directing laser light through the cuvette. We measure oscillation frequencies for freely swimming nematodes. Analysis of the far-field diffraction patterns reveals clues about the waveforms of the nematodes. Diffraction is the process of light bending around an object. In this case light is diffracted by the organisms. The light waves interfere and can form a diffraction pattern. A far-field, or Fraunhofer, diffraction pattern is formed if the screen-to-object distance is much larger than the diffracting object. In this case, the diffraction pattern can be calculated (modeled) using a Fourier transform.(2) C. elegans are free-living soil-dwelling nematodes that navigate in three dimensions. They move both on a solid matrix like soil or agar in a sinusoidal locomotory pattern called crawling and in liquid in a different pattern called swimming.(3) The roles played by sensory information provided by mechanosensory, chemosensory, and thermosensory cells that govern plastic changes in locomotory patterns and switches in patterns are only beginning to be elucidated.(4) We describe an optical approach to measuring nematode locomotion in three dimensions that does not require a microscope and will enable us to begin to explore the complexities of nematode locomotion under different conditions.

Detailed evaluation of the performance of microfluidic T mixers using fluorescence and ultraviolet resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Masca, Sergiu I.; Rodriguez-Mendieta, Iñigo R.; Friel, Claire T.; Radford, Sheena E.; Smith, D. Alastair

2006-05-01

A reliable device that produces efficient mixing with a short dead time has enormous utility in the kinetic analysis of biochemical and chemical processes. We have designed two different T mixers that use moderate flow rates (0.2-0.4ml/s), can monitor reactions up to several milliseconds, and achieve mixing times as low as 20μs. The two mixers are easy to build and dismantle, reliable, and can perform hundreds of experiments without blocking. The first mixer comprises a stainless steel block, containing a microchannel, glued to a quartz cuvette, containing a 200×200μm2 observation channel defining a conventional T mixer. The reactions are monitored by imaging the length of the observation channel onto a charge-coupled device camera. In the second mixer the entire T (200×200μm2 internal cross section) is contained within a 40-mm-long quartz cuvette. We have adopted a novel approach to controlling the entrance channel bore by inserting a stainless steel wire in order to increase the linear speed of the impinging fluids. Using a dye to visualize the flow profile inside the second T mixer, it was shown that in this T geometry segregation of the reactants is observed in the junction between the inlet channels and the observation channel (T junction) and mixing occurs entirely in the observation channel. We thoroughly tested the two mixers through several kinetic reactions using both fluorescence and ultraviolet resonance Raman spectroscopy measurements. We show that both mixers provide efficient mixing with nominal dead times (using 1:10 v /v dilution), calculated using the quenching of the fluorescence of N-acetyl-L-tryptophanamide by N-bromosuccinimide, of 200±20 and 100±10μs, for each mixer, respectively. However, the ability to monitor within the inlet channels and the entire observation channel of the second mixer shows that this standard approach to estimating the dead time is artifactual, since it relies on assuming a constant flow speed throughout the observation channel, a feature that we show is not adhered to at short distances from the T junction. Using both mixers the refolding of the A state of cytochrome c to the native state was followed by fluorescence and ultraviolet resonance Raman spectroscopy, revealing the ability of these instruments to provide insights into the early stages of protein folding using only milligrams of sample.

Effect of photosynthesis on the abundance of 18O13C16O in atmospheric CO2

NASA Astrophysics Data System (ADS)

Hofmann, Magdalena E. G.; Pons, Thijs L.; Ziegler, Martin; Lourens, Lucas J.; Röckmann, Thomas

2016-04-01

The abundance of the isotopologue 18O13C16O (Δ47) in atmospheric air is a promising new tracer for the atmospheric carbon cycle (Eiler and Schauble, 2004; Affek and Eiler, 2006; Affek et al., 2007). The large gross fluxes in CO2 between the atmosphere and biosphere are supposed to play a major role in controlling its abundance. Eiler and Schauble (2004) set up a box model describing the effect of air-leaf interaction on the abundance of 18O13C16O in atmospheric air. The main assumption is that the exchange between CO2 and water within the mesophyll cells will imprint a Δ47 value on the back-diffusing CO2 that reflects the leaf temperature. Additionally, kinetic effects due to CO2 diffusion into and out of the stomata are thought to play a role. We investigated the effect of photosynthesis on the residual CO2 under controlled conditions using a leaf chamber set-up to quantitatively test the model assumptions suggested by Eiler and Schauble (2004). We studied the effect of photosynthesis on the residual CO2 using two C3 and one C4 plant species: (i) sunflower (Helianthus annuus), a C3 species with a high leaf conductance for CO2 diffusion, (ii) ivy (Hedera hibernica), a C3 species with a low conductance, and (iii), maize (Zea mays), a species with the C4 photosynthetic pathway. We also investigated the effect of different light intensities (photosynthetic photon flux density of 200, 700 and 1800 μmol m2s-1), and thus, photosynthetic rate in sunflower and maize. A leaf was mounted in a cuvette with a transparent window and an adjustable light source. The air inside was thoroughly mixed, making the composition of the outgoing air equal to the air inside. A gas-mixing unit was attached at the entrance of the cuvette that mixed air with a high concentration of scrambled CO2 with a Δ47 value of 0 to 0.1‰ with CO2 free air to set the CO2 concentration of ingoing air at 500 ppm. The flow rate through the cuvette was adjusted to the photosynthetic activity of the leaf so that the CO2 concentration at the outlet was 400 ppm and varied between 0.6 and 1.5 L min-1. CO2 and H2O concentrations in air were monitored with an IRGA and air was sampled at the outlet with flasks. We found that the effect on Δ47 of the residual CO2 for the C3 species sunflower and ivy was proportional to the effect on δ18O of the residual CO2. The difference in Δ47 between the in- and outgoing CO2 was between -0.07 and 0.49‰ varying with the CO2 concentration in the chloroplasts relative to the bulk air (Cc/Ca). The Cc/Ca depends on conductance and photosynthetic activity, and was different for the two species and was manipulated with the light intensity. For the C4 species maize, a Δ47 value of -0.08±0.02‰ was observed. The slightly negative effect on Δ47may be related to its lower Cc/Ca ratio and possibly a lower carbonic anhydrase activity causing incomplete exchange with leaf water. We will discuss these results in light of the suggested fractionation processes and discuss the implication for the global Δ47 value of atmospheric CO2. References Affek H. P. and Eiler J. M., GCA 70, 1-12 (2006). Affek H. P., Xu X. and Eiler J. M., GCA 71, 5033-5043 (2007). Eiler J. M. and Schauble E., GCA 68, 4767-4777 (2004).

Rapid Detection of Microbial Contamination Using a Microfluidic Device.

PubMed

Al-Adhami, Mustafa; Tilahun, Dagmawi; Rao, Govind; Gurramkonda, Chandrasekhar; Kostov, Yordan

2017-01-01

A portable kinetics fluorometer is developed to detect viable cells which may be contaminating various samples. The portable device acts as a single-excitation, single-emission photometer that continuously measures fluorescence intensity of an indicator dye and plots it. The slope of the plot depends on the number of colony forming units per milliliter. The device uses resazurin as the indicator dye. Viable cells reduce resazurin to resorufin, which is more fluorescent. Photodiode is used to detect fluorescence change. The photodiode generated current proportional to the intensity of the light that reached it, and an op-amp is used in a transimpedance differential configuration to ensure amplification of the photodiode's signal. A microfluidic chip is designed specifically for the device. It acts as a fully enclosed cuvette, which enhances the resazurin reduction rate. In tests, the E. coli-containing media are injected into the microfluidic chip and the device is able to detect the presence of E. coli in LB media based on the fluorescence change that occurred in the indicator dye. The device provides fast, accurate, and inexpensive means to optical detection of the presence of viable cells and could be used in the field in place of more complex methods, i.e., loop-meditated isothermal amplification of DNA (LAMP) to detect bacteria in pharmaceutical samples (Jimenez et al., J Microbiol Methods 41(3):259-265, 2000) or measuring the intrinsic fluorescence of the bacterial or yeast chromophores (Estes et al., Biosens Bioelectron 18(5):511-519, 2003).

UV Absorption Spectroscopy in Water-Filled Antiresonant Hollow Core Fibers for Pharmaceutical Detection.

PubMed

Nissen, Mona; Doherty, Brenda; Hamperl, Jonas; Kobelke, Jens; Weber, Karina; Henkel, Thomas; Schmidt, Markus A

2018-02-06

Due to a worldwide increased use of pharmaceuticals and, in particular, antibiotics, a growing number of these substance residues now contaminate natural water resources and drinking supplies. This triggers a considerable demand for low-cost, high-sensitivity methods for monitoring water quality. Since many biological substances exhibit strong and characteristic absorption features at wavelengths shorter than 300 nm, UV spectroscopy presents a suitable approach for the quantitative identification of such water-contaminating species. However, current UV spectroscopic devices often show limited light-matter interaction lengths, demand sophisticated and bulky experimental infrastructure which is not compatible with microfluidics, and leave large fractions of the sample analyte unused. Here, we introduce the concept of UV spectroscopy in liquid-filled anti-resonant hollow core fibers, with large core diameters and lengths of approximately 1 m, as a means to overcome such limitations. This extended light-matter interaction length principally improves the concentration detection limit by two orders of magnitude while using almost the entire sample volume-that is three orders of magnitude smaller compared to cuvette based approaches. By integrating the fibers into an optofluidic chip environment and operating within the lowest experimentally feasible transmission band, concentrations of the application-relevant pharmaceutical substances, sulfamethoxazole (SMX) and sodium salicylate (SS), were detectable down to 0.1 µM (26 ppb) and 0.4 µM (64 ppb), respectively, with the potential to reach significantly lower detection limits for further device integration.

UV Absorption Spectroscopy in Water-Filled Antiresonant Hollow Core Fibers for Pharmaceutical Detection

PubMed Central

Nissen, Mona; Doherty, Brenda; Hamperl, Jonas; Kobelke, Jens; Weber, Karina; Henkel, Thomas; Schmidt, Markus A.

2018-01-01

Due to a worldwide increased use of pharmaceuticals and, in particular, antibiotics, a growing number of these substance residues now contaminate natural water resources and drinking supplies. This triggers a considerable demand for low-cost, high-sensitivity methods for monitoring water quality. Since many biological substances exhibit strong and characteristic absorption features at wavelengths shorter than 300 nm, UV spectroscopy presents a suitable approach for the quantitative identification of such water-contaminating species. However, current UV spectroscopic devices often show limited light-matter interaction lengths, demand sophisticated and bulky experimental infrastructure which is not compatible with microfluidics, and leave large fractions of the sample analyte unused. Here, we introduce the concept of UV spectroscopy in liquid-filled anti-resonant hollow core fibers, with large core diameters and lengths of approximately 1 m, as a means to overcome such limitations. This extended light-matter interaction length principally improves the concentration detection limit by two orders of magnitude while using almost the entire sample volume—that is three orders of magnitude smaller compared to cuvette based approaches. By integrating the fibers into an optofluidic chip environment and operating within the lowest experimentally feasible transmission band, concentrations of the application-relevant pharmaceutical substances, sulfamethoxazole (SMX) and sodium salicylate (SS), were detectable down to 0.1 µM (26 ppb) and 0.4 µM (64 ppb), respectively, with the potential to reach significantly lower detection limits for further device integration. PMID:29415468

Enzyme kinetics in acoustically levitated droplets of supercooled water: a novel approach to cryoenzymology.

PubMed

Weis, David D; Nardozzi, Jonathan D

2005-04-15

The rate of the alkaline phosphatase-catalyzed hydrolysis of 4-methylumbelliferone phosphate was measured in acoustically levitated droplets of aqueous tris (50 mM) at pH 8.5 at 22 +/- 2 degrees C and in supercooled solution at -6 +/- 2 degrees C. At 22 degrees C, the rate of product formation was in excellent agreement with the rate observed in bulk solution in a cuvette, indicating that the acoustic levitation process does not alter the enzyme activity. The rate of the reaction decreased 6-fold in supercooled solution at -6 +/- 2 degrees C. The acoustic levitator apparatus is described in detail.

Photothermoplastic recording media and its application in the holographic method of determination of the refractive index of liquid objects.

PubMed

Davidenko, N A; Davidenko, I I; Pavlov, V A; Chuprina, N G; Kravchenko, V V; Kuranda, N N; Mokrinskaya, E V; Studzinsky, S L

2018-03-10

The photothermoplastic medium based on the films of photosensitive polymeric composites with semiconductor properties is developed for application in optical information recording and storage, in holographic interferometry, as well as for medical purposes. This medium was used in the modified holographic device for determination of changes of the refractive index of homogeneous and inhomogeneous liquid objects. The technique and holographic equipment were modified by employing the specially developed and produced transparent cuvette of special shape and the phase shifting interferometry method. Experimentally demonstrated precision of the measurements is not less than 10 -5 .

SU-D-213-06: Dosimetry of Modulated Electron Radiation Therapy Using Fricke Gel Dosimeter

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

Gawad, M Abdel; Elgohary, M; Hassaan, M

Purpose: Modulated electron radiation therapy (MERT) has been proposed as an effective modality for treatment of superficial targets. MERT utilizes multiple beams of different energies which are intensity modulated to deliver optimized dose distribution. Energy independent dosimeters are thus needed for quantitative evaluations of MERT dose distributions and measurements of absolute doses delivered to patients. Thus in the current work we study the feasibility of Fricke gel dosimeters in MERT dosimetry. Methods: Batches of radiation sensitive Fricke gel is fabricated and poured into polymethyl methacrylate cuvettes. The samples were irradiated in solid water phantom and a thick layer of bolusmore » was used as a buildup. A spectrophotometer system was used for measuring the color changes (the absorbance) before and after irradiation and then we calculate net absorbance. We constructed calibration curves to relate the measured absorbance in terms of absorbed dose for all available electron energies. Dosimetric measurements were performed for mixed electron beam delivery and we also performed measurement for segmented field delivery with the dosimeter placed at the junction of two adjacent electron beams of different energies. Dose measured by our gel dosimetry is compared to that calculation from our precise treatment planning system. We also initiated a Monte Carlo study to evaluate the water equivalence of our dosimeters. MCBEAM and MCSIM codes were used for treatment head simulation and phantom dose calculation. PDDs and profiles were calculated for electron beams incident on a phantom designed with 1cm slab of Fricke gel. Results: The calibration curves showed no observed energy dependence with all studied electron beam energies. Good agreement was obtained between dose calculated and that obtained by gel dosimetry. Monte Carlo results illustrated the tissue equivalency of our Gel dosimeters. Conclusion: Fricke Gel dosimeters represent a good option for the dosimetric quality assurance prior to MERT application.« less

Interfacial force field characterization of a constrained vapor bubble thermosyphon using IAI

NASA Technical Reports Server (NTRS)

Dasgupta, Sunando; Plawsky, Joel L.; Wayner, Peter C., Jr.

1994-01-01

The isothermal profiles of the extended meniscus in a quartz cuvette were measured in a gravitational field using IAI (image analyzing interferometer) which is based on computer enhanced video microscopy of the naturally occurring interference fringes. The experimental results for heptane and pentane menisci were analyzed using the extended Young-Laplace Equation. These isothermal results characterized the interfacial force field in-situ at the start of the heat transfer experiments by quantifying the dispersion constant for the specific liquid-solid system. The experimentally obtained values of the disjoining pressures and the dispersion constants are compared to the subsequent non-isothermal experiments because one of the major variables in the heat sink capability of the CVBT is the dispersion constant. In all previous studies of micro heat pipes the value of the dispersion constant has been 'guesstimated'. The major advantages of the current glass cell is the ability to view the extended meniscus at all times. Experimentally, we find that the extended Young-Laplace Equation is an excellent model for for the force field at the solid-liquid vapor interfaces.

Nitrogen dioxide (NO2) uptake by vegetation controlled by atmospheric concentrations and plant stomatal aperture

NASA Astrophysics Data System (ADS)

Chaparro-Suarez, I. G.; Meixner, F. X.; Kesselmeier, J.

2011-10-01

Nitrogen dioxide (NO2) exchange between the atmosphere and five European tree species was investigated in the laboratory using a dynamic branch enclosure system (consisting of two cuvettes) and a highly specific NO2 analyzer. NO2 measurements were performed with a sensitive gas phase chemiluminescence NO detector combined with a NO2 specific (photolytic) converter, both from Eco-Physics (Switzerland). This highly specific detection system excluded bias from other nitrogen compounds. Investigations were performed at two light intensities (Photosynthetic Active Radiation, PAR, 450 and 900 μmol m-2 s-1) and NO2 concentrations between 0 and 5 ppb. Ambient parameters (air temperature and relative humidity) were held constant. The data showed dominant NO2 uptake by the respective tree species under all conditions. The results did not confirm the existence of a compensation point within a 95% confidence level, though we cannot completely exclude emission of NO2 under very low atmospheric concentrations. Induced stomatal stricture, or total closure, by changing light conditions, as well as by application of the plant hormone ABA (Abscisic Acid) caused a corresponding decrease of NO2 uptake. No loss of NO2 to plant surfaces was observed under stomatal closure and species dependent differences in uptake rates could be clearly related to stomatal behavior.

Measurement accuracy of a stressed contact lens during its relaxation period

NASA Astrophysics Data System (ADS)

Compertore, David C.; Ignatovich, Filipp V.

2018-02-01

We examine the dioptric power and transmitted wavefront of a contact lens as it releases its handling stresses. Handling stresses are introduced as part of the contact lens loading process and are common across all contact lens measurement procedures and systems. The latest advances in vision correction require tighter quality control during the manufacturing of the contact lenses. The optical power of contact lenses is one of the critical characteristics for users. Power measurements are conducted in the hydrated state, where the lens is resting inside a solution-filled glass cuvette. In a typical approach, the contact lens must be subject to long settling times prior to any measurements. Alternatively, multiple measurements must be averaged. Apart from potential operator dependency of such approach, it is extremely time-consuming, and therefore it precludes higher rates of testing. Comprehensive knowledge about the settling process can be obtained by monitoring multiple parameters of the lens simultaneously. We have developed a system that combines co-aligned a Shack-Hartmann transmitted wavefront sensor and a time-domain low coherence interferometer to measure several optical and physical parameters (power, cylinder power, aberrations, center thickness, sagittal depth, and diameter) simultaneously. We monitor these parameters during the stress relaxation period and show correlations that can be used by manufacturers to devise methods for improved quality control procedures.

Recording High Resolution 3D Lagrangian Motions In Marine Dinoflagellates using Digital Holographic Microscopic Cinematography

NASA Astrophysics Data System (ADS)

Sheng, J.; Malkiel, E.; Katz, J.; Place, A. R.; Belas, R.

2006-11-01

Detailed data on swimming behavior and locomotion for dense population of dinoflagellates constitutes a key component to understanding cell migration, cell-cell interactions and predator-prey dynamics, all of which affect algae bloom dynamics. Due to the multi-dimensional nature of flagellated cell motions, spatial-temporal Lagrangian measurements of multiple cells in high concentration are very limited. Here we present detailed data on 3D Lagrangian motions for three marine dinoflagellates: Oxyrrhis marina, Karlodinium veneficum, and Pfiesteria piscicida, using digital holographic microscopic cinematography. The measurements are performed in a 5x5x25mm cuvette with cell densities varying from 50,000 ˜ 90,000 cells/ml. Approximately 200-500 cells are tracked simultaneously for 12s at 60fps in a sample volume of 1x1x5 mm at a spatial resolution of 0.4x0.4x2 μm. We fully resolve the longitudinal flagella (˜200nm) along with the Lagrangian trajectory of each organism. Species dependent swimming behavior are identified and categorized quantitatively by velocities, radii of curvature, and rotations of pitch. Statistics on locomotion, temporal & spatial scales, and diffusion rate show substantial differences between species. The scaling between turning radius and cell dimension can be explained by a distributed stokeslet model for a self-propelled body.

The reciprocal iso-inhibition volume concept: A procedure for the evaluation in effect-directed analysis with thin-layer chromatography - using the thin-layer chromatography-luminescent bacteria assay as an example.

PubMed

Schulz, Wolfgang; Weiss, Stefan C; Weber, Walter H; Winzenbacher, Rudi

2017-10-13

In effect-directed analysis (EDA) with high-performance thin-layer chromatography (HPTLC), the effect is often detected using images. Thus, an approach to create inhibition chromatograms from these images was developed using the example of the HPTLC- bioluminescence inhibition test. A comparison between the cuvette test and the HPTLC test shows that the test on the plate is significantly more sensitive. To describe the strength of the effect, the EC 50 value is determined from the dose-response relationship. However, the inhibiting compounds are generally unknown and thus their concentrations are also unknown. Therefore, instead of the concentration, the known application volumes are used. This enables the calculation of the application volume necessary to achieve 50% inhibition. Since the volume is inversely proportional to the concentration, the reciprocal value of the calculated volume is indicated and is referred to as the reciprocal iso-inhibition volume (RIV). Using this RIV-concept, it is now possible to compare inhibition bands within and between plates. The entire evaluation is described by the means of two samples from a contaminated site using the bioluminescence inhibition. Copyright © 2017 Elsevier B.V. All rights reserved.

The reaction pathway of membrane-bound rat liver mitochondrial monoamine oxidase

PubMed Central

Houslay, Miles D.; Tipton, Keith F.

1973-01-01

1. A preparation of a partly purified mitochondrial outer-membrane fraction suitable for kinetic investigations of monoamine oxidase is described. 2. An apparatus suitable for varying the O2 concentration in a spectrophotometer cuvette is described. 3. The reaction catalysed by the membrane-bound enzyme is shown to proceed by a double-displacement (Ping Pong) mechanism, and a formal mechanism is proposed. 4. KCN, NaN3, benzyl cyanide and 4-cyanophenol are shown to be reversible inhibitors of the enzyme. 5. The non-linear reciprocal plot obtained with impure preparations of benzylamine, which is typical of high substrate inhibition, is shown to be due to aldehyde contamination of the substrate. PMID:4778271

High-performance colorimeter with an electronic bubble gate for use in miniaturized continuous-flow analyzers.

PubMed

Neeley, W E; Wardlaw, S C; Yates, T; Hollingsworth, W G; Swinnen, M E

1976-02-01

We describe a high-performance colorimeter with an electronic bubble gate for use with miniaturized continuous-flow analyzers. The colorimeter has a flow-through cuvette with optically flat quartz windows that allows a bubbled stream to pass freely without any breakup or retention of bubbles. The fluid volume in the light path is only 1.8 mul. The electronic bubble gate selectively removes that portion of the photodector signal produced by the air bubbles passing through the flow cell and allows that portion of the signal attributable to the fluid segment to pass to the recorder. The colorimeter is easy to use, rugged, inexpensive, and requires minimal adjustments.

Absorption spectroscopy of microalgae, cyanobacteria, and dissolved organic matter: Measurements in an integrating sphere cavity

NASA Astrophysics Data System (ADS)

Pogosyan, S. I.; Durgaryan, A. M.; Konyukhov, I. V.; Chivkunova, O. B.; Merzlyak, M. N.

2009-12-01

A device for integrating cavity absorption measurements (ICAM) with an internal diameter of 80 mm suitable for field research is described. The spectral features of the light absorption by some cyanobacteria, green algae, and diatoms in the integrating sphere were studied and the dependences of the absorption on the cell concentration were determined in comparison with the conventional measurements in a 1-cm cuvette. The sensitivity of the chlorophyll estimation with the ICAM reached 0.2-0.5 mg m-3. The results of the ICAM application for the direct analysis of the natural phytoplankton and dissolved organic (“yellow“) matter in the Black Sea and the Sea of Japan are described.

Aqueous glucose measurement using differential absorption-based frequency domain optical coherence tomography at wavelengths of 1310 nm and 1625 nm

NASA Astrophysics Data System (ADS)

John, Pauline; Manoj, Murali; Sujatha, N.; Vasa, Nilesh J.; Rao, Suresh R.

2015-07-01

This work presents a combination of differential absorption technique and frequency domain optical coherence tomography for detection of glucose, which is an important analyte in medical diagnosis of diabetes. Differential absorption technique is used to detect glucose selectively in the presence of interfering species especially water and frequency domain optical coherence tomography (FDOCT) helps to obtain faster acquisition of depth information. Two broadband super-luminescent diode (SLED) sources with centre wavelengths 1586 nm (wavelength range of 1540 to 1640 nm) and 1312 nm (wavelength range of 1240 to 1380 nm) and a spectral width of ≍ 60 nm (FWHM) are used. Preliminary studies on absorption spectroscopy using various concentrations of aqueous glucose solution gave promising results to distinguish the absorption characteristics of glucose at two wavelengths 1310 nm (outside the absorption band of glucose) and 1625 nm (within the absorption band of glucose). In order to mimic the optical properties of biological skin tissue, 2% and 10% of 20% intralipid with various concentrations of glucose (0 to 4000 mg/dL) was prepared and used as sample. Using OCT technique, interference spectra were obtained using an optical spectrum analyzer with a resolution of 0.5 nm. Further processing of the interference spectra provided information on reflections from the surfaces of the cuvette containing the aqueous glucose sample. Due to the absorption of glucose in the wavelength range of 1540 nm to 1640 nm, a trend of reduction in the intensity of the back reflected light was observed with increase in the concentration of glucose.

Hydrologic controls on Congo River particulate organic carbon source and reservoir age

NASA Astrophysics Data System (ADS)

Hemingway, J. D.; Schefuß, E.; Spencer, R. G.; Dinga, B. J.; Eglinton, T. I.; McIntyre, C.; Galy, V.

2016-12-01

Tropical rivers are a major source of organic matter (OM) to the coastal ocean and play a large role in the global carbon cycle. As such, it is critical to understand the sources, sinks, and transformations of OM during fluvial transit over seasonal and inter-annual timescales. Here we present dissolved organic carbon (DOC) concentrations, particulate OM (POM) composition (δ13C, δ15N, Δ14C, N/C), and glycerol dialkyl glycerol tetraether (GDGT) biomarker distributions from a 34-month time-series near the mouth of the Congo River. An end-member mixing model based on δ13C and N/C indicates that exported POM is consistently dominated by C3 tropical rainforest soil inputs, with increasing contributions by C3 tropical plant vegetation and decreasing contributions by autochthonous phytoplankton at high discharge. Calculated Δ14C values of the C3-soil end member reveal significant and variable pre-aging prior to export, especially during the year 2011 when southern-hemisphere discharge reached record lows (mean = -176‰, standard deviation = 93‰). In contrast, Δ14C values were stable near -50‰ between January and June 2013 when southern-hemisphere discharge was highest. These results indicate that headwater POM is diluted and/or overprinted by pre-aged soils during transit through the Cuvette Congolaise swamp forest, while left-bank tributaries export significantly less pre-aged material. GDGT distributions are in agreement, as the methylation and cyclization of branched tetraethers and the GDGT-0/crenarchaeol ratio reflect a significant incorporation of compounds produced in permanently inundated Cuvette Congolaise swamp-forest soils when discharge through this region is high, especially in 2011. This study provides a mechanistic link between hydrology and carbon cycling in the world's second largest tropical river and suggests that, if recent observed decreases in springtime precipitation over the Congo basin persist, future hydrologic conditions will further bias toward export of protracted, swamp-forest-derived OM sources.

A Fiber Optic Probe for Monitoring Protein Aggregation, Nucleation, and Crystallization

NASA Technical Reports Server (NTRS)

Ansari, Rafat R.; Suh, Kwang I.; Arabshahi, Alireza; Wilson, William W.; Bray, Terry L.; DeLucas, Lawrence J.

1996-01-01

Protein crystals are experimentally grown in hanging drops in microgravity experiments on-board the Space Shuttle orbiter. The technique of dynamic light scattering (DLS) can be used to monitor crystal growth process in hanging droplets (approx. 30 (L)) in microgravity experiments, but elaborate instrumentation and optical alignment problems have made in-situ applications difficult. In this paper we demonstrate that such experiments are now feasible. We apply a newly developed fiber optic probe to various earth and space (micro- gravity) bound protein crystallization system configurations to test its capability. These include conventional batch (cuvette or capillary) systems, hanging drop method in a six-pack hanging drop vapor diffusion apparatus (HDVDA), a modified HDVDA for temperature- induced nucleation and aggregation studies, and a newly envisioned dynamically controlled vapor diffusion system (DCVDS) configuration. Our compact system exploits the principles of DLS and offers a fast (within a few seconds) means of quantitatively and non-invasively monitoring the various growth stages of protein crystallization. In addition to DLS capability, the probe can also be used for performing single-angle static light scattering measurements. It utilizes extremely low levels of laser power (approx. few (W)) without a need of having any optical alignment and vibration isolation. The compact probe is also equipped with a miniaturized microscope for visualization of macroscopic protein crystals. This new optical diagnostic system opens up enormous opportunity for exploring new ways to grow good quality crystals suitable for x-ray crystallographic analysis and may help develop a concrete scientific basis for understanding the process of crystallization.

A micro-fluidic treadmill for observing suspended plankton in the lab

NASA Astrophysics Data System (ADS)

Jaffe, J. S.; Laxton, B.; Garwood, J. C.; Franks, P. J. S.; Roberts, P. L.

2016-02-01

A significant obstacle to laboratory studies of interactions between small organisms ( mm) and their fluid environment is our ability to obtain high-resolution images while allowing freedom of motion. This is because as the organisms sink, they will often move out of the field of view of the observation system. One solution to this problem is to impose a water circulation pattern that preserves their location relative to the camera system while imaging the organisms away from the glass walls. To accomplish this we have designed and created a plankton treadmill. Our computer-controlled system consists of a digital video camera attached to a macro or microscope and a micro-fluidic pump whose flow is regulated to maintain a suspended organism's position relative to the field of view. Organisms are detected and tracked in real time in the video frames, allowing a control algorithm to compensate for any vertical movement by adjusting the flow. The flow control can be manually adjusted using on-screen controls, semi-automatically adjusted to allow the user to select a particular organism to be tracked or fully automatic through the use of classification and tracking algorithms. Experiments with a simple cm-sized cuvette and a number of organisms that are both positively and negatively buoyant have demonstrated the success of the system in permitting longer observation times than would be possible in the absence of a controlled-flow environment. The subjects were observed using a new dual-view, holographic imaging system that provides 3-dimensional microscopic observations with relatively isotropic resolution. We will present the system design, construction, the control algorithm, and some images obtained with the holographic system, demonstrating its effectiveness. Small particles seeded into the flow clearly show the 3D flow fields around the subjects as they freely sink or swim.

Fluorescence spectroscopy for throat cancer detection using human saliva

NASA Astrophysics Data System (ADS)

Kumar, Pavan; Singh, Ashutosh; Zaffar, Mohammad; Pradhan, Asima

2018-02-01

Throat precancer detection using fluorescence from human saliva is reported here. It may be noted that accessing the throat for investigation is cumbersome and use of saliva as a diagnostic medium may ease the process. The study has been conducted on three groups of patients: oral squamous cell carcinoma (OSCC), dysplasia, and normal (control). An in-house developed compact set-up has been used for fluorescence measurements. The compact system consist of a 375 nm laser diode, collimating lens, long pass filter, fibers, and cuvette holder. Major and minor bands of flavin adenine dinucleotide (FAD) and porphyrin are observed in the spectra. A receiver operating characteristic (ROC) analysis has been used to evaluate the diagnostic performance. Area under the spectra has been chosen for discrimination among the groups and is able to differentiate OSCC to normal, dysplasia to normal, and OSCC to dysplasia with sensitivities 100% (48/48), 92% (32/35), 77% (37/48), and specificities 96% (50/52), 96% (50/52), 89% (31/35) with the accuracy of 98%, 94% and 82% respectively. Sensitivity and specificity, when differentiating OSCC to normal and dysplasia to normal, are significantly large, which indicates that human saliva may be an excellent diagnostic medium for early detection of throat cancer.

Red and infrared light distribution in blood

NASA Astrophysics Data System (ADS)

de Magalhães, Ana Carolina; Yoshimura, Elisabeth M.

2013-02-01

Low level laser therapy (LLLT) is used in several applications, including the reduction of inflammatory processes. It might be used to prevent the systemic inflammatory response syndrome (SIRS), which some patients develop after cardiopulmonary bypass (CPB) surgery. The objectives of this study were to investigate light distribution inside blood, in order to implement the LLLT during CPB, and, through this study, to determine the best wavelength and the best way to perform the treatment. The blood, diluted to the same conditions of CPB procedure was contained inside a cuvette and an optical fiber was used to collect the scattered light. Two wavelengths were used: 632.8 nm and 820 nm. Light distribution in blood inside CPB tubes was also evaluated. Compared to the 820 nm light, the 632.8 nm light is scattered further away from the laser beam, turning it possible that a bigger volume of blood be treated. The blood should be illuminated through the smallest diameter CPB tube, using at least four distinct points around it, in only one cross section, because the blood is kept passing through the tube all the time and the whole volume will be illuminated.

Evaluation of urine culture screening by light-scatter photometry

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

Hale, D.C.; Thrupp, L.D.; Matsen, J.M.

1981-08-01

Urine screening for bacteriuria by light-scatter photometry (Autobac) was evaluated for accuracy and compared with a colony count by the calibrated loop method. Incubation time, inoculum size, precision, and interference of particulate matter were evaluated in an effort to standardize the screening procedure. Results showed that urines could be accurately screened for Enterobacteriaceae by inoculating a single Autobac cuvette chamber with 0.1 or 0.2 ml of urine and determining the voltage change after four hours. A change of greater than or equal to 0.2 units indicates significant bacteriuria. Decreased accuracy was noted for urines having greater than 10(5) cfu/ml ofmore » Pseudomonas species or gram-positive cocci, possibly because these organisms grow more slowly.« less

Development of a 3D-Printed Collimated 90Sr Beta Source

NASA Astrophysics Data System (ADS)

Daniel, Byron; NuDot Collaboration

2017-09-01

Collimated beta particle sources based on 90Sr are common calibration sources for atomic decay detector research and development. Due to the short attenuation length of beta particles in matter, the exact geometry of a collimator can drastically change the rate and energy of beta particles exiting the source. 3D printing allows for the quick and easy prototyping of collimators with custom geometries. I will describe the development of a collimator that interfaces directly to a quartz cuvette for the characterization of liquid scintillator cocktails. Future work will include developing a source for the NuDot detector which aims to reconstruct MeV electrons using the separation of Cherenkov and scintillation light. MIT Summer Research Program.

Application of titration methods for measuring the contents of ammonium nitrogen and volatile fatty acids in agricultural biogas plants.

PubMed

Piątek, Michał; Lisowski, Aleksander; Lisowska, Barbara

2017-12-20

The aim of our research was to assess a relatively new method of estimating ammonium nitrogen concentration in anaerobic digestion of plant substrates. We analysed our own data, received from the anaerobic digestion of maize silage (PM), as well as data published by Purser et al. (2014) who measured energy crops and slurry (ECS), and food waste (FW). In our study, the process was monitored for VFA content that was determined by gas chromatography, and for the content of ammonium nitrogen determined using the HACH LANGE LCK 303 cuvette test. We created polynomial regression models that bind the content of ammonium nitrogen with the volume of H 2 SO 4 used to titrate the sample from initial pH to pH 5. To estimate parameters of model, the PM dataset was used. The obtained models were positively validated using ECS and FW datasets. Our results confirmed the effectiveness of the Purser et al. method with an average absolute error of less than 223mgl -1 of the VFA concentration, which was approximately 20-times less than the level that caused inhibition. In conclusion, we can affirm the suitability of using titration methods to assess the ammonium nitrogen content of bioreactors with a stable composition. Copyright © 2017 Elsevier B.V. All rights reserved.

Optical sensor for rapid microbial detection

NASA Astrophysics Data System (ADS)

Al-Adhami, Mustafa; Tilahun, Dagmawi; Rao, Govind; Kostov, Yordan

2016-05-01

In biotechnology, the ability to instantly detect contaminants is key to running a reliable bioprocess. Bioprocesses are prone to be contaminated by cells that are abundant in our environment; detection and quantification of these cells would aid in the preservation of the bioprocess product. This paper discusses the design and development of a portable kinetics fluorometer which acts as a single-excitation, single-emission photometer that continuously measures fluorescence intensity of an indicator dye, and plots it. Resazurin is used as an indicator dye since the viable contaminant cells reduce Resazurin toResorufin, the latter being strongly fluorescent. A photodiode detects fluorescence change by generating current proportional to the intensity of the light that reached it, and a trans-impedance differential op-amp ensures amplification of the photodiodes' signal. A microfluidic chip was designed specifically for the device. It acts as a fully enclosed cuvette, which enhances the Resazurin reduction rate. E. coli in LB media, along with Resazurin were injected into the microfluidic chip. The optical sensor detected the presence of E. coli in the media based on the fluorescence change that occurred in the indicator dye in concentrations as low as 10 CFU/ml. A method was devised to detect and determine an approximate amount of contamination with this device. This paper discusses application of this method to detect and estimate sample contamination. This device provides fast, accurate, and inexpensive means to optically detect the presence of viable cells.

Determination of Ethanol in Kombucha, Juices, and Alcohol-Free Beer by EnzytecTMLiquid Ethanol: Single-Laboratory Validation, First Action 2017.07.

PubMed

Lacorn, Markus; Hektor, Thomas

2018-04-04

Enzytec TM Liquid Ethanol is an enzymatic test for the determinationof ethanol in kombucha, juices, and alcohol-free beer. The kit contains two components in a ready-to-use format. Quantification is based on the catalytic activity of alcohol dehydrogenase, which oxidizes ethanol to acetaldehyde and converts NAD + to NADH. Measurement is performed in 3 mL cuvettes at 340 nm within 20 min. Samples with alcohol contents around 0.5% alcohol by volume need to be diluted 1:20 or 1:50 with water before measurement. Acetaldehyde interferes at concentrations higher than 3000 mg/L, whereas sulfite interferes at concentrations higher than 300 mg/L. The linear measurement range is from 0.03 up to 0.5 g/L ethanol, whereas LOD and LOQ are 1.9 and 3.3 mg/L ethanol, respectively. Kombucha with concentrations between 2.85 and 5.82 g/L showed relative repeatability standard deviation around 1%, whereas juices were below 2%. Results from a reproducibility experiment revealed that at a concentration of 0.1 g/L, the RSD R was at 2.5%, whereas at higher concentrations between 0.2 and 0.3 g/L, coefficients around 1% were obtained. Trueness was checked by using Cerilliant aqueous ethanol solutions and beer with concentration of 0.4 and 4 g/L (BCR-651 and BCR-652). Spiking of kombucha and juice samples resulted in recoveries between 95% and 104%. Acceptable stability was found for the whole test kit under accelerated conditions at 37°C for 2 weeks. The kit is also not susceptible to short freezing-thawing cycles and harsh transport conditions.

Phase partitioning, crystal growth, electrodeposition and cosmic ray experiments in microgravity

NASA Technical Reports Server (NTRS)

Wessling, Francis C.

1987-01-01

Five experiments are contained in one Get Away Special Canister (5 cu ft). The first utilizes microgravity to separate biological cells and to study the mechanism of phase partitioning in 12 separate cuvettes. Two experiments are designed to grow organic crystals by physical vapor transport. One experiment consists of eight electroplating cells with various chemicals to produce surfaces electroplated in microgravity. Some of the surfaces have micron sized particles of hard materials co-deposited during electrodeposition. The fifth experiment intercepts cosmic ray particles and records their paths on photographic emulsions. The first four experiments are controlled by an on-board C-MOS controller. The fifth experiment is totally passive. These are the first in Space. Their purpose is to create new commercial products with microgravity processing.

Detection of silver nanoparticles in seawater at ppb levels using UV-visible spectrophotometry with long path cells.

PubMed

Lodeiro, Pablo; Achterberg, Eric P; El-Shahawi, Mohammad S

2017-03-01

Silver nanoparticles (AgNPs) are emerging contaminants that are difficult to detect in natural waters. UV-visible spectrophotometry is a simple technique that allows detection of AgNPs through analysis of their characteristic surface plasmon resonance band. The detection limit for nanoparticles using up to 10cm path length cuvettes with UV-visible spectrophotometry is in the 0.1-10ppm range. This detection limit is insufficiently low to observe AgNPs in natural environments. Here we show how the use of capillary cells with an optical path length up to 200cm, forms an excellent technique for rapid detection and quantification of non-aggregated AgNPs at ppb concentrations in complex natural matrices such as seawater. Copyright © 2016 Elsevier B.V. All rights reserved.

Study directed at development of an implantable biotelemetry ion detector

NASA Technical Reports Server (NTRS)

Hanley, L. D.; Kress, D.

1971-01-01

A literature search was conducted to currently update known information in the field of ion-selective electrodes. The review attempts to identify present trends in cation and anions selective electrodes pertinent to the area of bioimplantable units. An electronic circuit was designed to provide the high impedance interface between the ion-selective sensors and signal-processing equipment. The resulting design emphasized the need for low power and miniaturization. Many of the circuits were constructed and used to evaluate the ion-selective electrodes. A cuvette capable of holding the ion-selective and the reference electrodes was designed and constructed. This equipment was used to evaluate commercially available ion-selective electrodes and the electrodes designed and constructed in the study. The results of the electrode tests are included.

Major diffusion leaks of clamp-on leaf cuvettes still unaccounted: how erroneous are the estimates of Farquhar et al. model parameters?

PubMed

Rodeghiero, Mirco; Niinemets, Ulo; Cescatti, Alessandro

2007-08-01

Estimates of leaf gas-exchange characteristics using standard clamp-on leaf chambers are prone to errors because of diffusion leaks. While some consideration has been given to CO(2) diffusion leaks, potential water vapour diffusion leaks through chamber gaskets have been neglected. We estimated diffusion leaks of two clamp-on Li-Cor LI-6400 (Li-Cor, Inc., Lincoln, NE, USA) leaf chambers with polymer foam gaskets and enclosing either 2 or 6 cm(2) leaf area, and conducted a sensitivity analysis of the diffusion leak effects on Farquhar et al. photosynthesis model parameters - the maximum carboxylase activity of ribulose 1 x 5-bisphosphate carboxylase/oxygenase (Rubisco) (V(cmax)), capacity for photosynthetic electron transport (J(max)) and non-photorespiratory respiration rate in light (R(d)). In addition, net assimilation rate (A(n)) versus intercellular CO(2) (C(i)) responses were measured in leaves of Mediterranean evergreen species Quercus ilex L. enclosing the whole leaf chamber in a polyvinyl fluoride bag flushed with the exhaust air of leaf chamber, thereby effectively reducing the CO(2) and water vapour gradients between ambient air and leaf chamber. For the empty chambers, average diffusion leak for CO(2), K(CO2), (molar flow rate corresponding to unit CO(2) mole fraction difference) was ca. 0.40 micromol s(-1). K(CO2) increased ca. 50% if a dead leaf was clamped between the leaf chamber. Average diffusion leak for H(2)O was ca. 5- to 10-fold larger than the diffusion leak for CO(2). Sensitivity analyses demonstrated that the consequence of a CO(2) diffusion leak was apparent enhancement of A(n) at high CO(2) mole fraction and reduction at lower CO(2) mole fraction, and overall compression of C(i) range. As the result of these modifications, Farquhar et al. model parameters were overestimated. The degree of overestimation increased in the order of V(cmax) < J(max) < R(d), and was larger for smaller chambers and for leaves with lower photosynthetic capacity, leading to overestimation of all three parameters by 70-290% for 2 cm(2), and by 10-60% for 6 cm(2) chamber. Significant diffusion corrections (5-36%) were even required for leaves with high photosynthetic capacity measured in largest chamber. Water vapour diffusion leaks further enhanced the overestimation of model parameters. For small chambers and low photosynthetic capacities, apparent C(i) was simulated to decrease with increasing A(n) because of simultaneous CO(2) and H(2)O diffusion leaks. Measurements in low photosynthetic capacity Quercus ilex leaves enclosed in 2 cm(2) leaf chamber exhibited negative apparent C(i) values at highest A(n). For the same leaves measured with the entire leaf chamber enclosed in the polyvinyl fluoride bag, C(i) and A(n) increased monotonically. While the measurements without the bag could be corrected for diffusion leaks, the required correction in A(n) and transpiration rates was 100-500%, and there was large uncertainty in Farquhar et al. model parameters derived from 'corrected'A(n)/C(i) response curves because of uncertainties in true diffusion leaks. These data demonstrate that both CO(2) and water vapour diffusion leaks need consideration in measurements with clamp-on leaf cuvettes. As plants in natural environments are often characterized by low photosynthetic capacities, cuvette designs need to be improved for reliable measurements in such species.

Validation of a Spectral Method for Quantitative Measurement of Color in Protein Drug Solutions.

PubMed

Yin, Jian; Swartz, Trevor E; Zhang, Jian; Patapoff, Thomas W; Chen, Bartolo; Marhoul, Joseph; Shih, Norman; Kabakoff, Bruce; Rahimi, Kimia

2016-01-01

A quantitative spectral method has been developed to precisely measure the color of protein solutions. In this method, a spectrophotometer is utilized for capturing the visible absorption spectrum of a protein solution, which can then be converted to color values (L*a*b*) that represent human perception of color in a quantitative three-dimensional space. These quantitative values (L*a*b*) allow for calculating the best match of a sample's color to a European Pharmacopoeia reference color solution. In order to qualify this instrument and assay for use in clinical quality control, a technical assessment was conducted to evaluate the assay suitability and precision. Setting acceptance criteria for this study required development and implementation of a unique statistical method for assessing precision in 3-dimensional space. Different instruments, cuvettes, protein solutions, and analysts were compared in this study. The instrument accuracy, repeatability, and assay precision were determined. The instrument and assay are found suitable for use in assessing color of drug substances and drug products and is comparable to the current European Pharmacopoeia visual assessment method. In the biotechnology industry, a visual assessment is the most commonly used method for color characterization, batch release, and stability testing of liquid protein drug solutions. Using this method, an analyst visually determines the color of the sample by choosing the closest match to a standard color series. This visual method can be subjective because it requires an analyst to make a judgment of the best match of color of the sample to the standard color series, and it does not capture data on hue and chroma that would allow for improved product characterization and the ability to detect subtle differences between samples. To overcome these challenges, we developed a quantitative spectral method for color determination that greatly reduces the variability in measuring color and allows for a more precise understanding of color differences. In this study, we established a statistical method for assessing precision in 3-dimensional space and demonstrated that the quantitative spectral method is comparable with respect to precision and accuracy to the current European Pharmacopoeia visual assessment method. © PDA, Inc. 2016.

Cost-effective and compact wide-field fluorescent imaging on a cell-phone.

PubMed

Zhu, Hongying; Yaglidere, Oguzhan; Su, Ting-Wei; Tseng, Derek; Ozcan, Aydogan

2011-01-21

We demonstrate wide-field fluorescent and darkfield imaging on a cell-phone with compact, light-weight and cost-effective optical components that are mechanically attached to the existing camera unit of the cell-phone. For this purpose, we used battery powered light-emitting diodes (LEDs) to pump the sample of interest from the side using butt-coupling, where the pump light was guided within the sample cuvette to uniformly excite the specimen. The fluorescent emission from the sample was then imaged using an additional lens that was positioned right in front of the existing lens of the cell-phone camera. Because the excitation occurs through guided waves that propagate perpendicular to our detection path, an inexpensive plastic colour filter was sufficient to create the dark-field background required for fluorescent imaging, without the need for a thin-film interference filter. We validate the performance of this platform by imaging various fluorescent micro-objects in 2 colours (i.e., red and green) over a large field-of-view (FOV) of ∼81 mm(2) with a raw spatial resolution of ∼20 μm. With additional digital processing of the captured cell-phone images, through the use of compressive sampling theory, we demonstrate ∼2 fold improvement in our resolving power, achieving ∼10 μm resolution without a trade-off in our FOV. Further, we also demonstrate darkfield imaging of non-fluorescent specimen using the same interface, where this time the scattered light from the objects is detected without the use of any filters. The capability of imaging a wide FOV would be exceedingly important to probe large sample volumes (e.g., >0.1 mL) of e.g., blood, urine, sputum or water, and for this end we also demonstrate fluorescent imaging of labeled white-blood cells from whole blood samples, as well as water-borne pathogenic protozoan parasites such as Giardia Lamblia cysts. Weighing only ∼28 g (∼1 ounce), this compact and cost-effective fluorescent imaging platform attached to a cell-phone could be quite useful especially for resource-limited settings, and might provide an important tool for wide-field imaging and quantification of various lab-on-a-chip assays developed for global health applications, such as monitoring of HIV+ patients for CD4 counts or viral load measurements.

Cost-effective and compact wide-field fluorescent imaging on a cell-phone†

PubMed Central

Zhu, Hongying; Yaglidere, Oguzhan; Su, Ting-Wei; Tseng, Derek

2011-01-01

We demonstrate wide-field fluorescent and darkfield imaging on a cell-phone with compact, light-weight and cost-effective optical components that are mechanically attached to the existing camera unit of the cell-phone. For this purpose, we used battery powered light-emitting diodes (LEDs) to pump the sample of interest from the side using butt-coupling, where the pump light was guided within the sample cuvette to uniformly excite the specimen. The fluorescent emission from the sample was then imaged using an additional lens that was positioned right in front of the existing lens of the cell-phone camera. Because the excitation occurs through guided waves that propagate perpendicular to our detection path, an inexpensive plastic colour filter was sufficient to create the dark-field background required for fluorescent imaging, without the need for a thin-film interference filter. We validate the performance of this platform by imaging various fluorescent micro-objects in 2 colours (i.e., red and green) over a large field-of-view (FOV) of ~81 mm2 with a raw spatial resolution of ~20 μm. With additional digital processing of the captured cell-phone images, through the use of compressive sampling theory, we demonstrate ~2 fold improvement in our resolving power, achieving ~10 μm resolution without a trade-off in our FOV. Further, we also demonstrate darkfield imaging of non-fluorescent specimen using the same interface, where this time the scattered light from the objects is detected without the use of any filters. The capability of imaging a wide FOV would be exceedingly important to probe large sample volumes (e.g., >0.1 mL) of e.g., blood, urine, sputum or water, and for this end we also demonstrate fluorescent imaging of labeled white-blood cells from whole blood samples, as well as water-borne pathogenic protozoan parasites such as Giardia Lamblia cysts. Weighing only ~28 g (~1 ounce), this compact and cost-effective fluorescent imaging platform attached to a cell-phone could be quite useful especially for resource-limited settings, and might provide an important tool for wide-field imaging and quantification of various lab-on-a-chip assays developed for global health applications, such as monitoring of HIV+ patients for CD4 counts or viral load measurements. PMID:21063582

The application of ink-jet technology for the coating and loading of drug-eluting stents.

PubMed

Tarcha, Peter J; Verlee, Donald; Hui, Ho Wah; Setesak, Jeff; Antohe, Bogdan; Radulescu, Delia; Wallace, David

2007-10-01

The combination of drugs with devices, where locally delivered drugs elute from the device, has demonstrated distinct advantages over therapies involving systemic or local drugs and devices administered separately. Drug-eluting stents are most notable. Ink jet technology offers unique advantages for the coating of very small medical devices with drugs and drug-coating combinations, especially in cases where the active pharmaceutical agent is very expensive to produce and wastage is to be minimized. For medical devices such as drug-containing stents, the advantages of ink-jet technology result from the controllable and reproducible nature of the droplets in the jet stream and the ability to direct the stream to exact locations on the device surfaces. Programmed target deliveries of 100 microg drug, a typical dose for a small stent, into cuvettes gave a standard deviation (SD) of dose of 0.6 microg. Jetting on coated, uncut stent tubes exhibited 100% capture efficiency with a 1.8 microg SD for a 137 microg dose. In preliminary studies, continuous jetting on stents can yield efficiencies up to 91% and coefficients of variation as low as 2%. These results indicate that ink-jet technology may provide significant improvement in drug loading efficiency over conventional coating methods.

Photosynthetic Response to Long- and Short-Term Changes in Carbon Dioxide in Sweetpotatoes Grown Hydroponically with Enhanced Mineral Nutrition

NASA Technical Reports Server (NTRS)

Hamilton, Casey; Terse, Anita; Hileman, Douglas R.; Mortley, Desmond G.; Hill, Jill

1998-01-01

Sweetpotato [Ipomoea batatas L.(Lam.)] has been selected by NASA as a potential food for long-term space missions. In previous experiments, sweetpotato plants grown hydroponically under elevated levels of CO2 depleted the nitrogen in the nutrient solution between the hi-weekly solution replacements. In this experiment, the effect of enhanced nutrient replenishment on photosynthetic rates of sweetpotato was determined. CO2 response curves were determined for "TU-82-155" and "Georgia-Jet" sweetpotatoes grown hydroponically in growth chambers at three different CO2 concentrations (400, 750, and 1000 micro-mol/mol CO2). Gas exchange measurements were made using infrared gas analysis, an open-flow gas exchange system, and a controlled-climate cuvette. Photosynthetic measurements were made at CO2 concentrations from 50-1000 micro-mol/mol CO2. Net photosynthetic rates showed an increase with increasing measurement CO2 in all nutrient regimes, but the response of photosynthetic rates to the growth CO2 conditions varied among the experiments and between the two varieties. Enhanced mineral nutrition led to increased net photosynthetic rates in "Georgia Jet" plants, but not in "TU-82-155" plants. The results of this study will help to determine the CO2 requirements for growth of sweetpotato on proposed space missions.

Volatile Organic Compound Emissions by Agricultural Crops

NASA Astrophysics Data System (ADS)

Ormeno, E.; Farres, S.; Gentner, D.; Park, J.; McKay, M.; Karlik, J.; Goldstein, A.

2008-12-01

Biogenic Volatile Organic Compounds (BVOCs) participate in ozone and aerosol formation, and comprise a substantial fraction of reactive VOC emission inventories. In the agriculturally intensive Central Valley of California, emissions from crops may substantially influence regional air quality, but emission potentials have not been extensively studied with advanced instrumentation for many important crops. Because crop emissions may vary according to the species, and California emission inventories are constructed via a bottom-up approach, a better knowledge of the emission rate at the species-specific level is critical for reducing uncertainties in emission inventories and evaluating emission model performance. In the present study we identified and quantified the BVOCs released by dominant agricultural crops in California. A screening study to investigate both volatile and semivolatile BVOC fractions (oxygenated VOCs, isoprene, monoterepenes, sesquiterpenes, etc.) was performed for 25 crop species (at least 3 replicates plants each), including branch enclosures of woody species (e.g. peach, mandarin, grape, pistachio) and whole plant enclosures for herbaceous species (e.g. onion, alfalfa, carrot), through a dynamic cuvette system with detection by PTRMS, in-situ GCMS/FID, and collection on carbon-based adsorbents followed by extraction and GCMS analysis. Emission data obtained in this study will allow inclusion of these crops in BVOC emission inventories and air quality simulations.

Absorbance detector for high performance liquid chromatography based on a deep-UV light-emitting diode at 235nm.

PubMed

da Silveira Petruci, João Flavio; Liebetanz, Michael G; Cardoso, Arnaldo Alves; Hauser, Peter C

2017-08-25

In this communication, we describe a flow-through optical absorption detector for HPLC using for the first time a deep-UV light-emitting diode with an emission band at 235nm as light source. The detector is also comprised of a UV-sensitive photodiode positioned to enable measurement of radiation through a flow-through cuvette with round aperture of 1mm diameter and optical path length of 10mm, and a second one positioned as reference photodiode; a beam splitter and a power supply. The absorbance was measured and related to the analyte concentration by emulating the Lambert-Beer law with a log-ratio amplifier circuitry. This detector showed noise levels of 0.30mAU, which is comparable with our previous LED-based detectors employing LEDs at 280 and 255nm. The detector was coupled to a HPLC system and successfully evaluated for the determination of the anti-diabetic drugs pioglitazone and glimepiride in an isocratic separation and the benzodiazepines flurazepam, oxazepam and clobazam in a gradient elution. Good linearities (r>0.99), a precision better than 0.85% and limits of detection at sub-ppm levels were achieved. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of the dispersion constant in a constrained vapor bubble thermosyphon

NASA Technical Reports Server (NTRS)

Dasgupta, Sunando; Plawsky, Joel L.; Wayner, Peter C., Jr.

1995-01-01

The isothermal profiles of the extended meniscus in a quartz cuvette were measured in a gravitational field using an image analyzing interferometer which is based on computer enhanced video microscopy of the naturally occurring interference fringes. The experimental results for heptane and pentane menisci were analyzed using the extended Young Laplace Equation. These isothermal results characterized the interfacial force field in-siru at the start of the heat transfer experiments by quantifying the dispersion constant, which is a function of the liquid-solid system and cleaning procedures. The experimentally obtained values of the disjoining pressure and the dispersion constants were compared to that predicted from the DLP theory and good agreements were obtained. The measurements are critical to the subsequent non-isothermal experiments because one of the major variables in the heat sink capability of the Constrained Vapor Bubble Thermosyphon, CVBT, is the dispersion constant. In all previous studies of micro heat pipes the value of the dispersion constant has been 'estimated'. One of the major advantages of the current glass cell is the ability to view the extended meniscus at all times. Experimentally, we find that the extended Young-Laplace Equation is an excellent model for the force field at the solid-liquid-vapor interfaces.

Improving acoustic streaming effects in fluidic systems by matching SU-8 and polydimethylsiloxane layers.

PubMed

Catarino, S O; Minas, G; Miranda, J M

2016-07-01

This paper reports the use of acoustic waves for promoting and improving streaming in tridimensional polymethylmethacrylate (PMMA) cuvettes of 15mm width×14mm height×2.5mm thickness. The acoustic waves are generated by a 28μm thick poly(vinylidene fluoride) - PVDF - piezoelectric transducer in its β phase, actuated at its resonance frequency: 40MHz. The acoustic transmission properties of two materials - SU-8 and polydimethylsiloxane (PDMS) - were numerically compared. It was concluded that PDMS inhibits, while SU-8 allows, the transmission of the acoustic waves to the propagation medium. Therefore, by simulating the acoustic transmission properties of different materials, it is possible to preview the acoustic behavior in the fluidic system, which allows the optimization of the best layout design, saving costs and time. This work also presents a comparison between numerical and experimental results of acoustic streaming obtained with that β-PVDF transducer in the movement and in the formation of fluid recirculation in tridimensional closed domains. Differences between the numerical and experimental results are credited to the high sensitivity of acoustic streaming to the experimental conditions and to limitations of the numerical method. The reported study contributes for the improvement of simulation models that can be extremely useful for predicting the acoustic effects of new materials in fluidic devices, as well as for optimizing the transducers and matching layers positioning in a fluidic structure. Copyright © 2016 Elsevier B.V. All rights reserved.

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

PubMed

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.

Shift in the chemical composition of dissolved organic matter in the Congo River network

NASA Astrophysics Data System (ADS)

Lambert, Thibault; Bouillon, Steven; Darchambeau, François; Massicotte, Philippe; Borges, Alberto V.

2016-09-01

The processing of terrestrially derived dissolved organic matter (DOM) during downstream transport in fluvial networks is poorly understood. Here, we report a dataset of dissolved organic carbon (DOC) concentrations and DOM composition (stable carbon isotope ratios, absorption and fluorescence properties) acquired along a 1700 km transect in the middle reach of the Congo River basin. Samples were collected in the mainstem and its tributaries during high-water (HW) and falling-water (FW) periods. DOC concentrations and DOM composition along the mainstem were found to differ between the two periods because of a reduced lateral mixing between the central water masses of the Congo River and DOM-rich waters from tributaries and also likely because of a greater photodegradation during FW as water residence time (WRT) increased. Although the Cuvette Centrale wetland (one of the world's largest flooded forests) continuously releases highly aromatic DOM in streams and rivers of the Congo Basin, the downstream transport of DOM was found to result in an along-stream gradient from aromatic to aliphatic compounds. The characterization of DOM through parallel factor analysis (PARAFAC) suggests that this transition results from (1) the losses of aromatic compounds by photodegradation and (2) the production of aliphatic compounds by biological reworking of terrestrial DOM. Finally, this study highlights the critical importance of the river-floodplain connectivity in tropical rivers in controlling DOM biogeochemistry at a large spatial scale and suggests that the degree of DOM processing during downstream transport is a function of landscape characteristics and WRT.

Nanoengineered optical urea biosensor for estimating hemodialysis parameters in spent dialysate.

PubMed

Swati, M; Hase, N K; Srivastava, Rohit

2010-08-31

An optical biosensing scheme based on urease encapsulated calcium alginate microspheres which are coated with polyelectrolyte nanofilms predominantly composed of cresol red (CR) dye is demonstrated in this paper. The dye molecules within the nanofilms are deposited via the layer-by-layer (LbL) self-assembly technique on the microspheres and used as the optical transducer. A flow through cell constructed using a cuvette attached to a fiber optic spectrometer was used to determine the response of the biosensor to standard urea solutions of different concentrations. The change in pH and the absorbance ratio was monitored with time and these results were used for measurements of urea concentrations in the spent dialysate fluid. The biological parameters controlling hemodialysis such as dialyzer clearance or Kt/V and percent removed urea (PRU) have also been reported. The results demonstrate that the urea biosensor is pH reversible with a sensitivity of 0.09 pH units/min and is able to detect a change of 0.005 ratio units in urea concentration ranging 0.1-60 mg dL(-1). The response time of the sensor was calculated as 8 min while the detection range of urea covered the levels that are present in the spent dialysate fluid. The results obtained in the analysis of biological samples were in good agreement with those obtained by a reference method, showing no significant differences at a confidence level of 95%. 2010 Elsevier B.V. All rights reserved.

Evaluation of a computer-assisted, kinetics-based enzyme-linked immunosorbent assay for detection of coronavirus antibodies in cats.

PubMed Central

Barlough, J E; Jacobson, R H; Downing, D R; Marcella, K L; Lynch, T J; Scott, F W

1983-01-01

A computer-assisted, kinetics-based enzyme-linked immunosorbent assay was adapted for the detection of coronavirus antibodies in feline serum. An alkaline antigen diluent (carbonate-bicarbonate buffer, pH 9.6) used in initial experiments produced diffuse, nonspecific color reactions in both viral and control antigen cuvettes which were correlated, paradoxically, with coronavirus antibody levels in test sera. These interfering reactions were minimized by use of lower-pH antigen diluents such as water and phosphate-buffered saline. Background kinetics-based enzyme-linked immunosorbent assay reactivity directed against a noncoronaviral component of antigen tissue culture fluids could then detected in numerous sera, particularly in samples with lower titers. Much of this reactivity was shown to be associated with bovine gamma globulins in cell culture fluid. It was not serum lot or species specific, since a variety of bovine serum lots as well as individual lots of serum from other mammalian and avian species reacted. Reactivity was markedly reduced when cells for antigen preparation were grown in gamma globulin-free bovine serum. Generation of corrected slope values from the kinetics-based enzyme-linked immunosorbent assay made it possible to correct for residual background reactivity in individual test sera and thus eliminate a potentially major source of false-positive reactions. Collectively, these studies indicated that the control of nonspecific reactivity in feline coronavirus serology is absolutely essential to obtain useful estimates of specific antibody responses. PMID:6300184

In vitro effect of sodium nitrite on platelet aggregation in human platelet rich plasma--preliminary report.

PubMed

Kadan, M; Doğanci, S; Yildirim, V; Özgür, G; Erol, G; Karabacak, K; Avcu, F

2015-10-01

The role of nitrates and nitric oxide on platelet functions has obtained an increasing attention with respect to their potential effects on cardiovascular disorders. In this study we aimed to analyze the effect of sodium nitrite on platelet functions in human platelets. This in vitro study was designed to show the effect of sodium nitrite on platelet functions in seven healthy volunteers. Blood samples were centrifuged to prepare platelet rich plasma and platelet poor plasma. Platelet rich plasma was diluted with the platelet poor plasma to have a final count of 300,000 ± 25,000 platelets. Platelet rich plasma was incubated with six different increasing doses (from 10 μM to 5 mM) of sodium nitrite for 1 hour at 37°C. Then stimulating agents including collagen (3 μg ml-1), adenosine diphosphate (10 μM), and epinephrine (10 μM) were added to the cuvette. Changes in light transmission were observed for 10 minutes. In addition spontaneous aggregation were performed in control group with all aggregating agents separately. Effect of sodium nitrite on agonist-induced platelet aggregation depends on the concentration of sodium nitrite. Compared with control group, agonist-induced platelet aggregations were significantly suppressed by sodium nitrite at the concentration of 5, 1.0 and 0.5 mM. Our results suggested that sodium nitrite has inhibitory effects in vitro on platelet aggregation in a dose-dependent manner.

Evaluation of a computer-assisted, kinetics-based enzyme-linked immunosorbent assay for detection of coronavirus antibodies in cats.

PubMed

Barlough, J E; Jacobson, R H; Downing, D R; Marcella, K L; Lynch, T J; Scott, F W

1983-02-01

A computer-assisted, kinetics-based enzyme-linked immunosorbent assay was adapted for the detection of coronavirus antibodies in feline serum. An alkaline antigen diluent (carbonate-bicarbonate buffer, pH 9.6) used in initial experiments produced diffuse, nonspecific color reactions in both viral and control antigen cuvettes which were correlated, paradoxically, with coronavirus antibody levels in test sera. These interfering reactions were minimized by use of lower-pH antigen diluents such as water and phosphate-buffered saline. Background kinetics-based enzyme-linked immunosorbent assay reactivity directed against a noncoronaviral component of antigen tissue culture fluids could then detected in numerous sera, particularly in samples with lower titers. Much of this reactivity was shown to be associated with bovine gamma globulins in cell culture fluid. It was not serum lot or species specific, since a variety of bovine serum lots as well as individual lots of serum from other mammalian and avian species reacted. Reactivity was markedly reduced when cells for antigen preparation were grown in gamma globulin-free bovine serum. Generation of corrected slope values from the kinetics-based enzyme-linked immunosorbent assay made it possible to correct for residual background reactivity in individual test sera and thus eliminate a potentially major source of false-positive reactions. Collectively, these studies indicated that the control of nonspecific reactivity in feline coronavirus serology is absolutely essential to obtain useful estimates of specific antibody responses.

Evaluation of a novel automated water analyzer for continuous monitoring of toxicity and chemical parameters in municipal water supply.

PubMed

Bodini, Sergio F; Malizia, Marzio; Tortelli, Annalisa; Sanfilippo, Luca; Zhou, Xingpeng; Arosio, Roberta; Bernasconi, Marzia; Di Lucia, Stefano; Manenti, Angela; Moscetta, Pompeo

2018-08-15

A novel tool, the DAMTA analyzer (Device for Analytical Monitoring and Toxicity Assessment), designed for fully automated toxicity measurements based on luminescent bacteria as well as for concomitant determination of chemical parameters, was developed and field-tested. The instrument is a robotic water analyzer equipped with a luminometer and a spectrophotometer, integrated on a thermostated reaction plate which contains a movable carousel with 80 cuvettes. Acute toxicity is measured on-line using a wild type Photobacterium phosphoreum strain with measurable bioluminescence and unaltered sensitivity to toxicants lasting up to ten days. The EC50 values of reference compounds tested were consistent with A. fischeri and P. phosphoreum international standards and comparable to previously published data. Concurrently, a laboratory trial demonstrated the feasibility of use of the analyzer for the determination of nutrients and metals in parallel to the toxicity measurements. In a prolonged test, the system was installed only in toxicity mode at the premises of the World Fair "Expo Milano-2015″, a high security site to ensure the quality of the supplied drinking water. The monitoring program lasted for six months during which ca. 2400 toxicity tests were carried out; the results indicated a mean non-toxic outcome of -5.5 ± 6.2%. In order to warrant the system's robustness in detecting toxic substances, Zn was measured daily with highly reproducible inhibition results, 70.8 ± 13.6%. These results assure that this novel toxicity monitor can be used as an early warning system for protection of drinking water sources from emergencies involving low probability/high impact contamination events in source water or treated water. Copyright © 2018 Elsevier Inc. All rights reserved.

Afterload-dependent flow fluctuation of centrifugal pump: should it be actively fixed?

PubMed

Nishida, H; Akazawa, T; Nishinaka, T; Aomi, S; Endo, M; Koyanagi, H

1998-05-01

To evaluate the clinical meaning and effects of afterload-dependent flow fluctuation in a centrifugal pump, concomitant measurement of flow rate and mixed venous oxygen saturation (SVO2) was performed in 5 cases of open heart surgery in which the patients underwent cardiopulmonary bypass (CPB) with the Terumo Capiox centrifugal pump. Continuous measurement of SVO2 using the 3M CDI System 100 was performed with a disposable cuvette incorporated into the drainage circuit. After the target flow rate of 2.4 L/min/m2 was obtained under a nonbeating condition, the pump rotational speed was fixed. During the cooling and low temperature period, SVO2 decreased as the flow rate spontaneously decreased but still stayed around 80% even with a 15-20% decrease in blood flow rate. This indicates that a luxury perfusion condition is ensured as long as the body temperature is kept low. In contrast, during the rewarming period, SVO2 decreased to around 70-75% despite a 15-25% spontaneous increase in flow rate. Although this level of SVO2 still indicates adequate systemic perfusion, there is a possibility of regional hypoperfusion in patients with such conditions as cerebrovascular disease. In conclusion, although diligent adjustment of the physiological fluctuating flow rate in the centrifugal pump seems unnecessary during conventional open heart surgery, manual control may be necessary especially during the rewarming period, normothermic surgery, or circulatory assist for shocked patients. From this study, we also conclude that the major benefit of the afterload-independent autoflow control system of the centrifugal pump is the improvement of safety in terms of the fixed reservoir level and the handling of cardiopulmonary bypass.

Cranz-Schardin camera with a large working distance for the observation of small scale high-speed flows.

PubMed

Skupsch, C; Chaves, H; Brücker, C

2011-08-01

The Cranz-Schardin camera utilizes a Q-switched Nd:YAG laser and four single CCD cameras. Light pulse energy in the range of 25 mJ and pulse duration of about 5 ns is provided by the laser. The laser light is converted to incoherent light by Rhodamine-B fluorescence dye in a cuvette. The laser beam coherence is intentionally broken in order to avoid speckle. Four light fibers collect the fluorescence light and are used for illumination. Different light fiber lengths enable a delay of illumination between consecutive images. The chosen interframe time is 25 ns, corresponding to 40 × 10(6) frames per second. Exemplarily, the camera is applied to observe the bow shock in front of a water jet, propagating in air at supersonic speed. The initial phase of the formation of a jet structure is recorded.

Design of Integrated Polarizer for Detection of Lard Impurities in Cooking Oil

NASA Astrophysics Data System (ADS)

Sugito, H.; Firdausi, K. S.; Putri, N. K.

2018-05-01

This research was conducted to find the “fingerprint” of the existence of lard in vegetable cooking oil. Integrated Polarizer is composed of light source, polarizer, analizer, cuvette, electrodes, and a camera. This tool works based on the transmission polarization method. Cooking oil used is palm oil that has been contaminated with chicken oil and lard the light source used is a green laser with wavelength of 532 ± 10 nm. Measurements are made by observing the change of transmission polarization angle. The results show that palm oil which contaminated by lard has the greatest polarization angle change compared to pure palm oil. The content of saturated fatty acids in lard is greater than pure palm oil resulting in a greater change in transmission polarization angles from the results showed that integrated polarizer can be used for detection of lard impurities in cooking oil

Comparison of lead and cadmium contents in cruciferous vegetables grown under diversified ecological conditions: Cracow region of Poland.

PubMed

Kapusta-Duch, Joanna; Leszczyńska, Teresa; Florkiewicz, Adam; Filipiak-Florkiewicz, Agnieszka

2011-01-01

The aim of the present study was to compare lead and cadmium contents in cruciferous vegetables grown under diversified ecological conditions for three consecutive years, independently of the climatic and agrotechnical conditions. The research was conducted in the Cracow region of Poland and tests vegetables near the Steelworks, from ecological farms, and from local markets. The heavy metal contents were determined using the validated Atomic Absorption Spectrometry method, including electrothermal atomization, with an ET-AAS graphite cuvette (Varian AA240Z, made by Varian). Cruciferous vegetables cultivated in the areas surrounding the steelworks were characterized by alarmingly high lead content versus ecological and commercially available vegetables, while the contents of this metal in vegetables from the two latter locations did not differ. It cannot be definitively stated that the origin of vegetables influenced their cadmium content.

A whole-tree chamber system for examining tree-level physiological responses of field-grown trees to environmental variation and climate change.

PubMed

Medhurst, Jane; Parsby, Jan; Linder, Sune; Wallin, Göran; Ceschia, Eric; Slaney, Michelle

2006-09-01

A whole-tree chamber (WTC) system was installed at Flakaliden in northern Sweden to examine the long-term physiological responses of field-grown 40-year-old Norway spruce trees [Picea abies (L.) Karst.] to climate change. The WTCs were designed as large cuvettes to allow the net tree-level CO(2) and water fluxes to be measured on a continuous basis. A total of 12 WTCs were used to impose combinations of atmospheric carbon dioxide concentration, [CO(2)], and air temperature treatments. The air inside the ambient and elevated [CO(2)] WTCs was maintained at 365 and 700 micromol mol(-1), respectively. The air temperature inside the ambient temperature WTCs tracked air temperature outside the WTCs. Elevated temperatures were altered on a monthly time-step and ranged between +2.8 and +5.6 degrees C above ambient temperature. The system allowed continuous, long-term measurement of whole-tree photosynthesis, night-time respiration and transpiration. The performance of the WTCs was assessed using winter and spring data sets. The ability of the WTC system to measure tree-level physiological responses is demonstrated. All WTCs displayed a high level of control over tracking of air temperatures. The set target of 365 micromol mol(-1) in the ambient [CO(2)] chambers was too low to be maintained during winter because of tree dormancy and the high natural increase in [CO(2)] over winter at high latitudes such as the Flakaliden site. Accurate control over [CO(2)] in the ambient [CO(2)] chambers was restored during the spring and the system maintained the elevated [CO(2)] target of 700 micromol mol(-1) for both measurement periods. Air water vapour deficit (VPD) was accurately tracked in ambient temperature WTCs. However, as water vapour pressure in all 12 WTCs was maintained at the level of non-chambered (reference) air, VPD of elevated temperature WTCs was increased.

Space and Time Resolved Detection of Platelet Activation and von Willebrand Factor Conformational Changes in Deep Suspensions.

PubMed

Biasetti, Jacopo; Sampath, Kaushik; Cortez, Angel; Azhir, Alaleh; Gilad, Assaf A; Kickler, Thomas S; Obser, Tobias; Ruggeri, Zaverio M; Katz, Joseph

2017-01-01

Tracking cells and proteins' phenotypic changes in deep suspensions is critical for the direct imaging of blood-related phenomena in in vitro replica of cardiovascular systems and blood-handling devices. This paper introduces fluorescence imaging techniques for space and time resolved detection of platelet activation, von Willebrand factor (VWF) conformational changes, and VWF-platelet interaction in deep suspensions. Labeled VWF, platelets, and VWF-platelet strands are suspended in deep cuvettes, illuminated, and imaged with a high-sensitivity EM-CCD camera, allowing detection using an exposure time of 1 ms. In-house postprocessing algorithms identify and track the moving signals. Recombinant VWF-eGFP (rVWF-eGFP) and VWF labeled with an FITC-conjugated polyclonal antibody are employed. Anti-P-Selectin FITC-conjugated antibodies and the calcium-sensitive probe Indo-1 are used to detect activated platelets. A positive correlation between the mean number of platelets detected per image and the percentage of activated platelets determined through flow cytometry is obtained, validating the technique. An increase in the number of rVWF-eGFP signals upon exposure to shear stress demonstrates the technique's ability to detect breakup of self-aggregates. VWF globular and unfolded conformations and self-aggregation are also observed. The ability to track the size and shape of VWF-platelet strands in space and time provides means to detect pro- and antithrombotic processes.

Ultrasensitive FRET-based DNA sensor using PNA/DNA hybridization.

PubMed

Yang, Lan-Hee; Ahn, Dong June; Koo, Eunhae

2016-12-01

In the diagnosis of genetic diseases, rapid and highly sensitive DNA detection is crucial. Therefore, many strategies for detecting target DNA have been developed, including electrical, optical, and mechanical methods. Herein, a highly sensitive FRET based sensor was developed by using PNA (Peptide Nucleic Acid) probe and QD, in which red color QDs are hybridized with capture probes, reporter probes and target DNAs by EDC-NHS coupling. The hybridized probe with target DNA gives off fluorescent signal due to the energy transfer from QD to Cy5 dye in the reporter probe. Compared to the conventional DNA sensor using DNA probes, the DNA sensor using PNA probes shows higher FRET factor and efficiency due to the higher reactivity between PNA and target DNA. In addition, to elicit the effect of the distance between the donor and the acceptor, we have investigated two types of the reporter probes having Cy5 dyes attached at the different positions of the reporter probes. Results show that the shorter the distance between QDs and Cy5s, the stronger the signal intensity. Furthermore, based on the fluorescence microscopy images using microcapillary chips, the FRET signal is enhanced to be up to 276% times stronger than the signal obtained using the cuvette by the fluorescence spectrometer. These results suggest that the PNA probe system conjugated with QDs can be used as ultrasensitive DNA nanosensors. Copyright © 2016. Published by Elsevier B.V.

Elevated carbon dioxide influences yield and photosynthetic responses of hydroponically-grown sweetpotato

NASA Technical Reports Server (NTRS)

Mortley, D.; Hill, J.; Loretan, P.; Bonsi, C.; Hill, W.; Hileman, D.; Terse, A.

1996-01-01

The response of 'TI-155' and 'Georgia Jet' sweetpotato cultivars to elevated CO2 concentrations of 400 (ambient), 750 and 1000 micromoles mol-1 were evaluated under controlled environment conditions using the nutrient film technique (NFT). Growth chamber conditions included photosynthetic photon flux (PPF) of 600 micromoles m-2 s-1, 14/10 light/dark period, and 70% +/- 5% RH. Plants were grown using a modified half-Hoagland nutrient solution with a pH range of 5.5-6.0 and an electrical conductivity of 0.12 S m-1. Gas exchange measurements were made using infrared gas analysis, an open-flow gas exchange system, and a controlled-climate cuvette. Photosynthetic (Pn) measurements were made at CO2 ranges of 50 to 1000 micromoles mol-1. Storage root yield/plant increased with CO2 up to 750 but declined at 1000 micromoles mol-1. Storage root dry matter (DM) and foliage dry weight increased with increasing CO2. Harvest index (HI) for both cultivars was highest at 750 micromoles mol-1. The PPF vs Pn curves were typical for C3 plants with saturation occurring at approximately 600 micromoles m-2 s-1. CO2 concentration did not significantly influence net Pn, transpiration, water-use-efficiency (WUE), and stomatal conductance. As measurement CO2 concentration increased, net Pn and WUE increased while transpiration and stomatal conductance decreased.

Real-time optical studies of respiratory Complex I turnover.

PubMed

Belevich, Nikolai; Belevich, Galina; Verkhovskaya, Marina

2014-12-01

Reduction of Complex l (NADH:ubiquinone oxidoreductase l) from Escherichia coli by NADH was investigated optically by means of an ultrafast stopped-flow approach. A locally designed microfluidic stopped-flow apparatus with a low volume (0.21Jl) but a long optical path (10 mm) cuvette allowed measurements in the time range from 270 ).IS to seconds. The data acquisition system collected spectra in the visible range every 50 )JS. Analysis of the obtained time-resolved spectral changes upon the reaction of Complex I with NADH revealed three kinetic components with characteristic times of <270 ).IS, 0.45-0.9 ms and 3-6 ms, reflecting reduction of different FeS clusters and FMN. The rate of the major ( T = 0.45-0.9 ms) component was slower than predicted by electron transfer theory for the reduction of all FeS clusters in the intraprotein redox chain. This delay of the reaction was explained by retention of NAD+ in the catalytic site. The fast optical changes in the time range of 0.27- 1.5 ms were not altered significantly in the presence of 1 0-fold excess of NAD+ over NADH. The data obtained on the NuoF E95Q variant of Complex I shows that the single amino acid replacement in the catalytic site caused a strong decrease of NADH binding and/or the hydride transfer from bound NADH to FMN.

Investigating the sources and sinks of water of Congo's wetlands

NASA Astrophysics Data System (ADS)

Paiva, R. C. D.; O'Loughlin, F.; Alsdorf, D. E.; Durand, M. T.; Beighley, E., II; Calmant, S.; Lee, H.; Santos Da Silva, J.

2014-12-01

The Congo is the second largest river basin in the world and indeed there is still a lot to be investigated about the hydrology of this system. This region presents extensive wetlands that may play an important role on the hydrology, carbon and ecological dynamics of the Congo. However, previous studies indicate that these wetlands behave differently from the Amazon, other major rainforest basin, and how water enters and leaves the Cuvette Centrale wetland is still to be quantified. We investigate the sources and sinks of water to the Congo's wetlands. Our analyses range from simple examinations of precipitation and evaporation historical data to remote sensing datasets and 2 D hydrodynamic modelling of Congo wetlands. Early results show that water levels at wetlands are usually higher than adjacent Congo River water levels and amplitude of variation is considerably smaller. Also, floodplain channels are not observed in this region indicating that surface flows are diffusive. Mean annual precipitation range from 1600 to 2000 mm/year, evapotranspiration estimates are approximately 1100 mm/year while some estimates of groundwater recharge indicate values larger than 300 mm/year. These assessments suggest that volumes coming from local water balance could flood the wetlands to depths of only a few centimeters. Preliminary 2D hydrodynamic simulations show that water coming from main rivers produces at upstream areas can flood only a small part of wetland, mainly alongside these rivers.

Emission of Volatile Sulfur Compounds from Spruce Trees 1

PubMed Central

Rennenberg, Heinz; Huber, Beate; Schröder, Peter; Stahl, Klaus; Haunold, Werner; Georgii, Hans-Walter; Slovik, Stefan; Pfanz, Hardy

1990-01-01

Spruce (Picea Abies L.) trees from the same clone were supplied with different, but low, amounts of plant available sulfate in the soil (9.7-18.1 milligrams per 100 grams of soil). Branches attached to the trees were enclosed in a dynamic gas exchange cuvette and analyzed for the emission of volatile sulfur compounds. Independent of the sulfate supply in the soil, H2S was the predominant reduced sulfur compound continuously emitted from the branches with high rates during the day and low rates in the night. In the light, as well as in the dark, the rates of H2S emission increased exponentially with increasing water vapor flux from the needles. Approximately 1 nanomole of H2S was found to be emitted per mole of water. When stomata were closed completely, only minute emission of H2S was observed. Apparently, H2S emission from the needles is highly dependent on stromatal aperture, and permeation through the cuticle is negligible. In several experiments, small amounts of dimethylsulfide and carbonylsulfide were also detected in a portion of the samples. However, SO2 was the only sulfur compound consistently emitted from branches of spruce trees in addition to H2S. Emission of SO2 mainly proceeded via an outburst starting before the beginning of the light period. The total amount of SO2 emitted from the needles during this outburst was correlated with the plant available sulfate in the soil. The diurnal changes in sulfur metabolism that may result in an outburst of SO2 are discussed. PMID:16667315

PLS-NIR determination of five parameters in different types of Chinese rice wine

NASA Astrophysics Data System (ADS)

Yu, Haiyan; Ying, Yibin; Fu, Xiaping; Lu, Huishan

2005-11-01

To evaluate the applicability of near infrared spectroscopy for determination of the five enological parameters (alcoholic degree, pH value, total acid and amino acid nitrogen, °Brix) of Chinese rice wine, transmission spectra were collected in the spectral range from 12500 to 3800 cm-1 in a 1 mm path length rectangular quartz cuvette with air as reference at room temperature. Five calibration equations for the five parameters were established between the reference data and spectra by partial least squares (PLS) regression, separately. The best calibration results were achieved for the determination of alcoholic degree and °Brix. The RPD (ration of the standard deviation of the samples to the SECV) values of the calibration for both alcoholic degree and °Brix were higher than 3 (4.30 and 7.94, respectively), which demonstrated the robustness and power of the calibration models. The determination coefficients (R2) for alcoholic degree and °Brix were 0.987 and 0.991, respectively. The performance of pH, total acid and amino acid nitrogen was not as good as that of alcoholic degree and °Brix. The RPD values for the three parameters were 1.48, 1.85 and 1.82, respectively, and R2 values were 0.964, 0.970 and 0.971, respectively. In validation step, R2 value of the five parameters are all higher than 0.7, especially for alcoholic degree and °Brix (0.968 and 0.956, respectively). The results demonstrated that NIR spectroscopy could be used to predict the concentration of the five enological parameters in Chinese rice wine.

Lichens show that fungi can acclimate their respiration to seasonal changes in temperature.

PubMed

Lange, Otto L; Green, T G Allan

2005-01-01

Five species of lichens, the majority members of a soil-crust community ( Cladonia convoluta, Diploschistes muscorum, Fulgensia fulgens, Lecanora muralis, Squamarina lentigera) showed seasonal changes of temperature sensitivity of their dark respiration (DR) to such an extent that several substantially met the definition of full acclimation, i.e. near identical DR under different nocturnal temperature conditions during the course of the year. C. convoluta, for example, had maximal DR at 5 degrees C of -0.42, -1.11 and -0.09 nmol CO(2) g(-1) s(-1) in autumn, winter, and summer, respectively, a tenfold range. However, at the mean night temperatures for the same three seasons, 9.7 degrees C, 4.2 degrees C and 13.6 degrees C, maximal DR were almost identical at -1.11, -0.93, and -1.45 nmol CO(2) g(-1) s(-1). The information was extracted from measurements using automatic cuvettes that continuously recorded a sample lichen's gas exchange every 30 min under near-natural conditions. The longest period (for L. muralis) covered 15 months and 22,000 data sets whilst, for the other species studied, data blocks were available throughout the calendar year. The acclimation of DR means that maximal net carbon fixation rates remain substantially similar throughout the year and are not depressed by increased carbon loss by respiration in warmer seasons. This is especially important for lichens because of their normally high rate of DR compared to net photosynthesis. We suggest that lichens, especially soil-crust species, could be a suitable model for fungi generally, a group of organisms for which little is known about temperature acclimation because of the great difficulty in separating the organism from its growth medium. Fungi, whether saprophytic, symbiotic or parasitic, including soil lichens, are important components of soil ecosystems and contribute much of the respired CO(2) from these systems. Temperature acclimation by fungi would mean that expected increases in carbon losses caused by global climate warming from soil ecosystems might not be as extensive as first thought. This would ameliorate this positive feedback loop present in some climate models and might substantially lower the predicted warming.

SU-E-T-410: Fringe Stability and Phase Shift Measurements in a Michelson Interferometer for Optical Calorimetry

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

Flores-Martinez, E; Malin, M; DeWerd, L

2014-06-01

Purpose: To identify the variables limiting the resolution of a Michelson interferometer used to measure phase shifts (PS) in water as part of a radiometric calorimeter. Methods: We investigated the output stability of a He-Ne laser and a laser diode. The short and long term stability of the fringe pattern in a Michelson interferometer was tested with different types of lasers, thermal insulation arrangements, damping systems and optical mounts to optimize system performance. PS were induced by electrically heating water in a 1 cm quartz cuvette located in one of the interferometer arms. The PS was calculated from fringe intensitymore » changes and compared to a calculated PS using thermocouple-measured temperature changes in the water. Results: The intensity of the laser diode is more stable, but the gas laser’s profile is more suitable for fringe analysis and has better temporal coherence. The laser requires a warm-up time of 4 hours before its output is stabilized (SNR>95). The fringe’s stability strongly depends on the thermal insulation. When the interferometer is exposed to ambient temperature swings of 0.7 K, it is not possible to stabilize the fringe pattern. Enclosing the system in a 2.5 cm-thick Styrofoam box improves the SNR, but further insulation will be needed to increase the SNR above 50. High frequency noise is significantly reduced by damping the system.Inducing a temperature rise in water, starting at 299 K, the average temperature increase for a 2π PS is 0.29 ± 0.02 K and the proportionality constant is -21.1 ± 0.8 radians/K. This is 5.8% lower than the calculated value using the thermocouple. Conclusion: Interferometric PS measurements of temperature may provide an alternative to thermistors for water calorimetry. The resolution of the current prototype is limited by ambient temperature stability. Calculated and measured thermally-induced PS in water agreed to within 5.8%.« less

Liquid-handling Lego robots and experiments for STEM education and research

PubMed Central

Gerber, Lukas C.; Calasanz-Kaiser, Agnes; Hyman, Luke; Voitiuk, Kateryna; Patil, Uday

2017-01-01

Liquid-handling robots have many applications for biotechnology and the life sciences, with increasing impact on everyday life. While playful robotics such as Lego Mindstorms significantly support education initiatives in mechatronics and programming, equivalent connections to the life sciences do not currently exist. To close this gap, we developed Lego-based pipetting robots that reliably handle liquid volumes from 1 ml down to the sub-μl range and that operate on standard laboratory plasticware, such as cuvettes and multiwell plates. These robots can support a range of science and chemistry experiments for education and even research. Using standard, low-cost household consumables, programming pipetting routines, and modifying robot designs, we enabled a rich activity space. We successfully tested these activities in afterschool settings with elementary, middle, and high school students. The simplest robot can be directly built from the widely used Lego Education EV3 core set alone, and this publication includes building and experiment instructions to set the stage for dissemination and further development in education and research. PMID:28323828

Liquid-handling Lego robots and experiments for STEM education and research.

PubMed

Gerber, Lukas C; Calasanz-Kaiser, Agnes; Hyman, Luke; Voitiuk, Kateryna; Patil, Uday; Riedel-Kruse, Ingmar H

2017-03-01

Liquid-handling robots have many applications for biotechnology and the life sciences, with increasing impact on everyday life. While playful robotics such as Lego Mindstorms significantly support education initiatives in mechatronics and programming, equivalent connections to the life sciences do not currently exist. To close this gap, we developed Lego-based pipetting robots that reliably handle liquid volumes from 1 ml down to the sub-μl range and that operate on standard laboratory plasticware, such as cuvettes and multiwell plates. These robots can support a range of science and chemistry experiments for education and even research. Using standard, low-cost household consumables, programming pipetting routines, and modifying robot designs, we enabled a rich activity space. We successfully tested these activities in afterschool settings with elementary, middle, and high school students. The simplest robot can be directly built from the widely used Lego Education EV3 core set alone, and this publication includes building and experiment instructions to set the stage for dissemination and further development in education and research.

Non-invasive technique to measure biogeochemical parameters (pH and O2) in a microenvironment: Design and applications

NASA Astrophysics Data System (ADS)

Li, Biting; Seliman, Ayman; Pales, Ashley; Liang, Weizhen; Sams, Allison; Darnault, Christophe; Devol, Timothy

2017-04-01

The primary objectives of this research are to do the pH and O2 sensor foils calibration and then to test them in applications. Potentially, this project can be utilized to monitor the fate and transport of radionuclides in porous media. The information for physical and chemical parameters (e.g. pH and O2) is crucial to know when determining contaminants' behavior and transport in the environment. As a non-invasive method, optical imaging technique using a DSLR camera could capture data on the foil when it fluoresces, and gives a high temporal and spatial resolution during the experimental period. The calibration procedures were done in cuvettes in a row. The preliminary experiments could measure pH value in the range from 4.5 to 7.5, and O2 concentration from 0 mg/L to 20.74 mg/L. Applications of sensor foils have involved nano zero valent and acid rain experiments in order to obtain a gradient of parameter changes.

Monoterpene emission from ponderosa pine

NASA Technical Reports Server (NTRS)

Lerdau, Manual; Dilts, Stephen B.; Westberg, Hal; Lamb, Brian K.; Allwine, Eugene J.

1994-01-01

We explore the variability in monoterpene emissions from ponderosa pine beyond that which can be explained by temperature alone. Specifically, we examine the roles that photosynthesis and needle monoterpene concentrations play in controlling emissions. We measure monoterpene concentrations and emissions, photosynthesis, temperature, and light availability in the late spring and late summer in a ponderosa pine forest in central Oregon. We use a combination of measurements from cuvettes and Teflon bag enclosures to show that photosynthesis is not correlated with emissions in the short term. We also show that needle monoterpene concentrations are highly correlated with emissions for two compounds, alpha-pinene and beta-pinene, but that Delta-carene concentrations are not correlated with emissions. We suggest that direct effects of light and photosynthesis do not need to be included in emission algorithms. Our results indicate that the role of needle concentration bears further investigation; our results for alpha-pinene and beta-pinene are explainable by a Raoult's law relationship, but we cannot yet explain the cause of our results with Delta-carene.

Evaporation from a meniscus within a capillary tube in microgravity

NASA Technical Reports Server (NTRS)

Hallinan, K. P.

1993-01-01

The following represents a summary of progress made on the project 'Evaporation from a Capillary Meniscus in Microgravity' being conducted at the University of Dayton during the period 1 Dec. 1992 to 30 Nov. 1993. The efforts during this first year of the grant focused upon the following specific tasks: (1) application of a 3-D scattering particle image velocimetry technique to thin film velocity field measurement; (2) modeling the thermo-fluid behavior of the evaporating meniscus in 0-g within large diameter capillaries; (3) conceptualization of the space flight test cell (loop) configuration; (4) construction of prototypes of the test loop configuration; (5) conduct of experiments in 0-g in the 2.2 second drop tower at NASA-LeRC to study evaporation from a capillary meniscus within a square cuvette; and (6) investigation of the effect of vibrations on the stability of the meniscus. An overview of the work completed within these six task areas is presented.

Isolation of Lightning-Competent Soil Bacteria

PubMed Central

Cérémonie, Hélène; Buret, François; Simonet, Pascal; Vogel, Timothy M.

2004-01-01

Artificial transformation is typically performed in the laboratory by using either a chemical (CaCl2) or an electrical (electroporation) method. However, laboratory-scale lightning has been shown recently to electrotransform Escherichia coli strain DH10B in soil. In this paper, we report on the isolation of two “lightning-competent” soil bacteria after direct electroporation of the Nycodenz bacterial ring extracted from prairie soil in the presence of the pBHCRec plasmid (Tcr, Spr, Smr). The electrotransformability of the isolated bacteria was measured both in vitro (by electroporation cuvette) and in situ (by lightning in soil microcosm) and then compared to those of E. coli DH10B and Pseudomonas fluorescens C7R12. The electrotransformation frequencies measured reached 10−3 to 10−4 by electroporation and 10−4 to 10−5 by simulated lightning, while no transformation was observed in the absence of electrical current. Two of the isolated lightning-competent soil bacteria were identified as Pseudomonas sp. strains. PMID:15466589

Comparative study of uranyl(VI) and -(V) carbonato complexes in an aqueous solution.

PubMed

Ikeda, Atsushi; Hennig, Christoph; Tsushima, Satoru; Takao, Koichiro; Ikeda, Yasuhisa; Scheinost, Andreas C; Bernhard, Gert

2007-05-14

Electrochemical, complexation, and electronic properties of uranyl(VI) and -(V) carbonato complexes in an aqueous Na2CO3 solution have been investigated to define the appropriate conditions for preparing pure uranyl(V) samples and to understand the difference in coordination character between UO22+ and UO2+. Cyclic voltammetry using three different working electrodes of platinum, gold, and glassy carbon has suggested that the electrochemical reaction of uranyl(VI) carbonate species proceeds quasi-reversibly. Electrolysis of UO22+ has been performed in Na2CO3 solutions of more than 0.8 M with a limited pH range of 11.7 < pH < 12.0 using a platinum mesh electrode. It produces a high purity of the uranyl(V) carbonate solution, which has been confirmed to be stable for at least 2 weeks in a sealed glass cuvette. Extended X-ray absorption fine structure (EXAFS) measurements revealed the structural arrangement of uranyl(VI) and -(V) tricarbonato complexes, [UO2(CO3)3]n- [n = 4 for uranyl(VI), 5 for uranyl(V)]. The bond distances of U-Oax, U-Oeq, U-C, and U-Odist are determined to be 1.81, 2.44, 2.92, and 4.17 A for the uranyl(VI) complex and 1.91, 2.50, 2.93, and 4.23 A for the uranyl(V) complex, respectively. The validity of the structural parameters obtained from EXAFS has been supported by quantum chemical calculations for the uranyl(VI) complex. The uranium LI- and LIII-edge X-ray absorption near-edge structure spectra have been interpreted in terms of electron transitions and multiple-scattering features.

Electroporation System for Sterilizing Water

NASA Technical Reports Server (NTRS)

Schlager, Kenneth J.

2005-01-01

A prototype of an electroporation system for sterilizing wastewater or drinking water has been developed. In electroporation, applied electric fields cause transient and/or permanent changes in the porosities of living cells. Electroporation at lower field strengths can be exploited to increase the efficiency of chemical disinfection (as in chlorination). Electroporation at higher field strengths is capable of inactivating and even killing bacteria and other pathogens, without use of chemicals. Hence, electroporation is at least a partial alternative to chlorination. The transient changes that occur in micro-organisms at lower electric-field strengths include significantly increased uptake of ions and molecules. Such increased uptake makes it possible to achieve disinfection at lower doses of chemicals (e.g., chlorine or ozone) than would otherwise be needed. Lower doses translate to lower costs and reduced concentrations of such carcinogenic chemical byproducts as trichloromethane. Higher electric fields cause cell membranes to lose semipermeability and thereby become unable to function as selective osmotic barriers between the cells and the environment. This loss of function is the cause of the cell death at higher electric-field intensities. Experimental evidence does not indicate cell lysis but, rather, combined leaking of cell proteins out of the cells as well as invasion of foreign chemical compounds into the cells. The concept of electroporation is not new: it has been applied in molecular biology and genetic engineering for decades. However, the laboratory-scale electroporators used heretofore have been built around small (400-microliter) cuvettes, partly because the smallness facilitates the generation of electric fields of sufficient magnitude to cause electroporation. Moreover, most laboratory- scale electroporators have been designed for testing static water. In contrast, the treatment cell in the present system is much larger and features a flow-through geometry, such that electric fields strong enough to effect 99.9- percent disinfection can be applied to water flowing in a pipe.

Modified Blumlein pulse-forming networks for bioelectrical applications.

PubMed

Romeo, Stefania; Sarti, Maurizio; Scarfì, Maria Rosaria; Zeni, Luigi

2010-07-01

Intense nanosecond pulsed electric fields (nsPEFs) have been shown to induce, on intracellular structures, interesting effects dependent on electrical exposure conditions (pulse length and amplitude, repetition frequency and number of pulses), which are known in the literature as "bioelectrical effects" (Schoenbach et al., IEEE Trans Plasma Sci 30:293-300, 2002). In particular, pulses with a shorter width than the plasma membrane charging time constant (about 100 ns for mammalian cells) can penetrate the cell and trigger effects such as permeabilization of intracellular membranes, release of Ca(2+) and apoptosis induction. Moreover, the observed effects have led to exploration of medical applications, like the treatment of melanoma tumors (Nuccitelli et al., Biochem Biophys Res Commun 343:351-360, 2006). Pulsed electric fields allowing such effects usually range from several tens to a few hundred nanoseconds in duration and from a few to several tens of megavolts per meter in amplitude (Schoenbach et al., IEEE Trans Diel Elec Insul 14:1088-1109, 2007); however, the biological effects of subnanosecond pulses have been also investigated (Schoenbach et al., IEEE Trans Plasma Sci 36:414-422, 2008). The use of such a large variety of pulse parameters suggests that highly flexible pulse-generating systems, able to deliver wide ranges of pulse durations and amplitudes, are strongly required in order to explore effects and applications related to different exposure conditions. The Blumlein pulse-forming network is an often-employed circuit topology for the generation of high-voltage electric pulses with fixed pulse duration. An innovative modification to the Blumlein circuit has been recently devised which allows generation of pulses with variable amplitude, duration and polarity. Two different modified Blumlein pulse-generating systems are presented in this article, the first based on a coaxial cable configuration, matching microscopic slides as a pulse-delivery system, and the other based on microstrip transmission lines and designed to match cuvettes for the exposure of cell suspensions.

Absorption into fluorescence. A method to sense biologically relevant gas molecules

NASA Astrophysics Data System (ADS)

Strianese, Maria; Varriale, Antonio; Staiano, Maria; Pellecchia, Claudio; D'Auria, Sabato

2011-01-01

In this work we present an innovative optical sensing methodology based on the use of biomolecules as molecular gating nano-systems. Here, as an example, we report on the detection ofanalytes related to climate change. In particular, we focused our attention on the detection ofnitric oxide (NO) and oxygen (O2). Our methodology builds on the possibility of modulating the excitation intensity of a fluorescent probe used as a transducer and a sensor molecule whose absorption is strongly affected by the binding of an analyte of interest used as a filter. The two simple conditions that have to be fulfilled for the method to work are: (a) the absorption spectrum of the sensor placed inside the cuvette, and acting as the recognition element for the analyte of interest, should strongly change upon the binding of the analyte and (b) the fluorescence dye transducer should exhibit an excitation band which overlaps with one or more absorption bands of the sensor. The absorption band of the sensor affected by the binding of the specific analyte should overlap with the excitation band of the transducer. The high sensitivity of fluorescence detection combined with the use of proteins as highly selective sensors makes this method a powerful basis for the development of a new generation of analytical assays. Proof-of-principle results showing that cytochrome c peroxidase (CcP) for NO detection and myoglobin (Mb) for O2 detection can be successfully used by exploiting our new methodology are reported. The proposed technology can be easily expanded to the determination of different target analytes.

Estimation of surface water storage in the Congo Basin

NASA Astrophysics Data System (ADS)

O'Loughlin, F.; Neal, J. C.; Schumann, G.; Beighley, E.; Bates, P. D.

2015-12-01

For many large river basins, especially in Africa, the lack of access to in-situ measurements, and the large areas involved, make modelling of water storage and runoff difficult. However, remote sensing datasets are useful alternative sources of information, which overcome these issues. In this study, we focus on the Congo Basin and, in particular, the cuvette central. Despite being the second largest river basin on earth and containing a large percentage of the world's tropical wetlands and forest, little is known about this basin's hydrology. Combining discharge estimates from in-situ measurements and outputs from a hydrological model, we build the first large-scale hydrodynamic model for this region to estimate the volume of water stored in the corresponding floodplains and to investigate how important these floodplains are to the behaviour of the overall system. This hydrodynamic model covers an area over 1.6 million square kilometres and 13 thousand kilometres of rivers and is calibrated to water surface heights at 33 virtual gauging stations obtained from ESA's Envisat satellite. Our results show that the use of different sources of discharge estimations and calibration via Envisat observations can produce accurate water levels and downstream discharges. Our model produced un-biased (bias =-0.08 m), sub-metre Root Mean Square Error (RMSE =0.862 m) with a Nash-Sutcliffe efficiency greater than 80% (NSE =0.81). The spatial-temporal variations in our simulated inundated areas are consistent with the pattern obtained from satellites. Overall, we find a high correlation coefficient (R =0.88) between our modelled inundated areas and those estimated from satellites.

Photolytic generation of nitric oxide through a porous glass partitioning membrane.

PubMed

Zhelyaskov, V R; Godwin, D W

1998-01-01

We report a new method of generating nitric oxide that possesses several potential advantages for experimental use. This method consists of a microphotolysis chamber where NO is released by illuminating photolabile NO donors with light from a xenon lamp. NO then diffuses through a porous glass membrane to the experimental preparation. We observed that the rate of NO generation is a linear function of light intensity. Due to a dynamic equilibrium between the mechanisms of NO generation and dissipation (by diffusion or oxidation) the NO concentration in the experimental cuvette can be reversibly and reproducibly controlled. The major potential advantages of this device include its use as a NO point source, and the ability to partition the NO donor compound from the experimental preparation by a porous glass membrane. The diffusion of the caging moiety through the membrane is insignificant as seen by absorption spectroscopy due to its large relative size to NO. In this way, the porous glass membrane protects the preparation from the potential bioactive effects of the caging moiety, which is an important consideration for biological experiments.

Direct 3D Printing of Catalytically Active Structures

DOE PAGES

Manzano, J. Sebastian; Weinstein, Zachary B.; Sadow, Aaron D.; ...

2017-09-22

3D printing of materials with active functional groups can provide custom-designed structures that promote chemical conversions. Catalytically active architectures were produced by photopolymerizing bifunctional molecules using a commercial stereolithographic 3D printer. Functionalities in the monomers included a polymerizable vinyl group to assemble the 3D structures and a secondary group to provide them with active sites. The 3D-printed architectures containing accessible carboxylic acid, amine, and copper carboxylate functionalities were catalytically active for the Mannich, aldol, and Huisgen cycloaddition reactions, respectively. The functional groups in the 3D-printed structures were also amenable to post-printing chemical modification. And as proof of principle, chemically activemore » cuvette adaptors were 3D printed and used to measure in situ the kinetics of a heterogeneously catalyzed Mannich reaction in a conventional solution spectrophotometer. In addition, 3D-printed millifluidic devices with catalytically active copper carboxylate complexes were used to promote azide-alkyne cycloaddition under flow conditions. The importance of controlling the 3D architecture of the millifluidic devices was evidenced by enhancing reaction conversion upon increasing the complexity of the 3D prints.« less

Direct 3D Printing of Catalytically Active Structures

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

Manzano, J. Sebastian; Weinstein, Zachary B.; Sadow, Aaron D.

3D printing of materials with active functional groups can provide custom-designed structures that promote chemical conversions. Catalytically active architectures were produced by photopolymerizing bifunctional molecules using a commercial stereolithographic 3D printer. Functionalities in the monomers included a polymerizable vinyl group to assemble the 3D structures and a secondary group to provide them with active sites. The 3D-printed architectures containing accessible carboxylic acid, amine, and copper carboxylate functionalities were catalytically active for the Mannich, aldol, and Huisgen cycloaddition reactions, respectively. The functional groups in the 3D-printed structures were also amenable to post-printing chemical modification. And as proof of principle, chemically activemore » cuvette adaptors were 3D printed and used to measure in situ the kinetics of a heterogeneously catalyzed Mannich reaction in a conventional solution spectrophotometer. In addition, 3D-printed millifluidic devices with catalytically active copper carboxylate complexes were used to promote azide-alkyne cycloaddition under flow conditions. The importance of controlling the 3D architecture of the millifluidic devices was evidenced by enhancing reaction conversion upon increasing the complexity of the 3D prints.« less

Ultralow-threshold multiphoton-pumped lasing from colloidal nanoplatelets in solution

PubMed Central

Li, Mingjie; Zhi, Min; Zhu, Hai; Wu, Wen-Ya; Xu, Qing-Hua; Jhon, Mark Hyunpong; Chan, Yinthai

2015-01-01

Although multiphoton-pumped lasing from a solution of chromophores is important in the emerging fields of nonlinear optofluidics and bio-photonics, conventionally used organic dyes are often rendered unsuitable because of relatively small multiphoton absorption cross-sections and low photostability. Here, we demonstrate highly photostable, ultralow-threshold multiphoton-pumped biexcitonic lasing from a solution of colloidal CdSe/CdS nanoplatelets within a cuvette-based Fabry–Pérot optical resonator. We find that colloidal nanoplatelets surprisingly exhibit an optimal lateral size that minimizes lasing threshold. These nanoplatelets possess very large gain cross-sections of 7.3 × 10−14 cm2 and ultralow lasing thresholds of 1.2 and 4.3 mJ cm−2 under two-photon (λexc=800 nm) and three-photon (λexc=1.3 μm) excitation, respectively. The highly polarized emission from the nanoplatelet laser shows no significant photodegradation over 107 laser shots. These findings constitute a more comprehensive understanding of the utility of colloidal semiconductor nanoparticles as the gain medium in high-performance frequency-upconversion liquid lasers. PMID:26419950

Coloured Dissolved Organic Matter (CDOM) dynamics in small surface reservoirs in semiarid Brazil

NASA Astrophysics Data System (ADS)

Coelho, Christine; Foerster, Saskia; Heim, Birgit; de Araujo, Jose Carlos

2016-04-01

Coloured Dissolved Organic Matter (CDOM) is one of the major light absorbing constituents in freshwaters. Supplied from degradation of components of the aquatic environment, it consists mainly of humic substances and its concentration is strongly related to primary production, often associated to macrophytes. It plays a central role in several biological and chemical processes affecting the bioavailability of nutrients in aquatic ecosystems. Therefore CDOM can be regarded as a water quality indicator. We used the spectral absorption and spectral slope for understanding CDOM dynamics in surface reservoirs in the Brazilian semiarid region. The analysis was based on water samples collected in three reservoirs in a total of ten sampling locations in the period June 2014 to November 2015 with monthly to bi-monthly intervals totaling 120 samples. The collected water samples were filtered through cellulose acetate membrane filters. Subsequently, spectral absorbance was measured in a Lambda 950 UV-VIS spectrometer in the spectral range 250 to 800 nm using a quartz cuvette with 5 cm optical path. From the absorbance measurement, we obtained CDOM content using the specific absorption coefficient at 440nm as well as spectral slope. The average slope for the entire period for all reservoirs is 0,018, but we found a considerable increase in spectral slope values after the wet period (between February 2014 and June 2014) for the reservoirs São Nicolau and Paus Branco while Marengo reservoir showed only slight variations during this period, but exhibited an increase only in the dry period. Regarding aCDOM(440), the average was equal to 2,55 for Marengo, 5,70 for São Nicolau, and 3,53 for Paus Branco reservoir indicating different characteristics of these reservoirs. We noticed a decrease in the absorption coefficient for São Nicolau and Paus Branco reservoirs at the end of the wet period whereas for Marengo reservoir this value showed a different behavior. Spectral slope and spectral absorption seem consistent and, among other possible factors, its dynamics were affected by high evaporation and low precipitation, typical conditions for semiarid regions in the tropics. The results show also evidence of the hysteresis phenomenon related to humic substance properties. However, it is important to consider also other water quality parameters in order to assess the whole interaction occurring in the reservoirs under eutrophic conditions. This is a first study of the application of spectral absorption and spectral slope of CDOM for small reservoirs in semiarid Brazil providing additional information to the traditional water quality measurements. In the future, we plan to relate the in-situ measurements to satellite imagery to study spatio-temporal water quality dynamics and relate them to land use changes.

Acid-base transport systems in a polarized human intestinal cell monolayer: Caco-2.

PubMed

Osypiw, J C; Gleeson, D; Lobley, R W; Pemberton, P W; McMahon, R F

1994-09-01

Acid-base transport systems have been incompletely characterized in intact intestinal epithelial cells. We therefore studied the human cell line Caco-2, cultured on Teflon membranes to form confluent monolayers with apical microvilli on transmission electron microscopy and progressive enrichment in microvillar hydrolases. Monolayers (16- to 25-day-old), loaded with the pH-sensitive dye BCECF-AM (2',7'-bis (carboxyethyl)-5-carboxyfluorescein), were mounted in a spectrofluorometer cuvette to allow selective superfusion of apical and basolateral surfaces with Hepes- or HCO(3-)-buffered media. Intracellular pH (pHi) was measured by dual-excitation spectrofluorimetry; calibration was with standards containing nigericin and 110 mM K+ corresponding to measured intracellular [K+] in Caco-2 cell monolayers. In HCO(3-)-free (Hepes-buffered) media, bilateral superfusion with 1 mM amiloride or with Na(+)-free media reversibly inhibited pHi recovery from an intracellular acid load (NH4Cl pulse) by 86 and 98% respectively. Selective readdition of Na+ to the apical or basolateral superfusate also induced a pHi recovery, which was inhibited by ipsilateral but not by contralateral amiloride (1 mM). The pHi recovery induced by apical Na+ readdition had a Michaelis constant (Km) for Na+ of 30 mM and a relatively high inhibitor constant (Ki) for amiloride of 45.5 microM. Initial pHi in HCO(3-)-buffered media was lower than in the absence of HCO3- (7.35 vs. 7.80). pHi recovery from an acid load in HCO3- was Na- dependent but was inhibited only 18% by 1 mM amiloride. The amiloride-independent pHi recovery was inhibited 49% by pre-incubation of cells in 5 mM DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid). These data suggest that Caco-2 cells possess: (a) both apical and basolateral membrane Na(+)-H+ exchange mechanisms, the apical exchanger being relatively resistant to amiloride, similar to apical Na(+)-H+ exchangers in several normal epithelia; and (b) a Na(-)-dependent HCO3- transport system, either Na(+)-HCO3- cotransport or Na(-)-dependent Cl(-)-HCO3- exchange.

Ambient Aerosol in Southeast Asia: High Resolution Aerosol Mass Spectrometer Measurements Over Oil Palm (Elaeis guineensis)

NASA Astrophysics Data System (ADS)

Phillips, G.; Dimarco, C.; Misztal, P.; Nemitz, E.; Farmer, D.; Kimmel, J.; Jimenez, J.

2008-12-01

The emission of organic compounds in the troposphere is important factor in the formation of secondary organic aerosol (SOA). A very large proportion of organic material emitted globally is estimated to arise from biogenic sources, with almost half coming from tropical and sub-tropical forests. Preliminary analyses of leave cuvette emission studies suggest that oil palm (Elaeis guineensis) is a significantly larger source of isoprene than tropical forest. Much larger sources of isoprene over oil palm allied with a larger anthropogenic component of local emissions contrast greatly with the remote tropical forest environment and therefore the character of SOA formed may differ significantly. These issues, allied with the high price of palm oil on international markets leading to increased use of land for oil palm production, could give rise to rapidly changing chemical and aerosol regimes in the tropics. It is therefore important to understand the current emissions and composition of organic aerosol over all important land-uses in the tropical environment. This in turn will lead to a greater understanding of the present, and to an improvement in predictive capacity for the future system. To help address these issues, a high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) was deployed in the Sabahmas (PPB OIL) oil palm plantation near Lahad Datu, in Eastern Sabah, as part of the field component of the Aerosol Coupling in the Earth System (ACES) project, part of the UK NERC APPRAISE program. This project was allied closely with measurements made of similar chemical species and aerosol components at a forest site in the Danum Valley as part of the UK Oxidant and Particle Photochemical Processes above a Southeast Asian tropical rainforest (OP3) project. Measurements of submicron non- refractory aerosol composition are presented along with some preliminary analysis of chemically resolved aerosol fluxes made with a new eddy covariance system, based on the HR-ToF-AMS. The measurements are interpreted in the context of the measurements over tropical rain forest at Danum and aircraft measurements across Sabah.

High sensitivity liquid phase measurements using broadband cavity enhanced absorption spectroscopy (BBCEAS) featuring a low cost webcam based prism spectrometer.

PubMed

Qu, Zhechao; Engstrom, Julia; Wong, Donald; Islam, Meez; Kaminski, Clemens F

2013-11-07

Cavity enhanced techniques enable high sensitivity absorption measurements in the liquid phase but are typically more complex, and much more expensive, to perform than conventional absorption methods. The latter attributes have so far prevented a wide spread use of these methods in the analytical sciences. In this study we demonstrate a novel BBCEAS instrument that is sensitive, yet simple and economical to set up and operate. We use a prism spectrometer with a low cost webcam as the detector in conjunction with an optical cavity consisting of two R = 0.99 dielectric mirrors and a white light LED source for illumination. High sensitivity liquid phase measurements were made on samples contained in 1 cm quartz cuvettes placed at normal incidence to the light beam in the optical cavity. The cavity enhancement factor (CEF) with water as the solvent was determined directly by phase shift cavity ring down spectroscopy (PS-CRDS) and also by calibration with Rhodamine 6G solutions. Both methods yielded closely matching CEF values of ~60. The minimum detectable change in absorption (αmin) was determined to be 6.5 × 10(-5) cm(-1) at 527 nm and was limited only by the 8 bit resolution of the particular webcam detector used, thus offering scope for further improvement. The instrument was used to make representative measurements on dye solutions and in the determination of nitrite concentrations in a variation of the widely used Griess Assay. Limits of detection (LOD) were ~850 pM for Rhodamine 6G and 3.7 nM for nitrite, respectively. The sensitivity of the instrument compares favourably with previous cavity based liquid phase studies whilst being achieved at a small fraction of the cost hitherto reported, thus opening the door to widespread use in the community. Further means of improving sensitivity are discussed in the paper.

Fire severity impacts trajectories of vegetative regrowth and δ13C in organic pools and fluxes in Siberian/Alaskan forests

NASA Astrophysics Data System (ADS)

Fessenden, J. E.; Randerson, J. T.; Schuur, E.; Zimov, S.

2002-12-01

Stable carbon isotope ratios of carbon dioxide and leaf organic matter were measured in boreal forests of varying age and fire severity in Siberia and Alaska. This study focused on moderate and extreme severity burn sites in neighboring Alaskan forests ranging from 2 years to 160 years and Siberian forests ranging from 1 year to 200 years. The Alaskan forests were composed primarily of black spruce (Picea Mariana) and quaking aspen (Populus tremuloides) with a shift in species dominance from aspen to spruce approximately 50 years after fire disturbance. The Siberian forests were composed of Dahurian larch (Larix gmelinii). The understory species are the same in both Siberia and Alaska: dwarf birch (Betula nana), willow (Salix alaxensis), blueberry (Vaccinium ovalifolium), cranberry (Vaccinium vitis-idaea), and various moss and lichen species. Our aim was to determine how disturbance influenced local and regional carbon isotopic ratios in organic pools and fluxes. Samples of organic δ13C in whole leaf tissue were collected from the dominant species of each forest. δ13CO2 and [CO2] were measured on soil cuvette- and canopy-CO2 to determine the isotopic ratio of soil and ecosystem respiration, respectively. Plant functional type primarily controlled the organic δ13C composition, and changes in abundance of different plant functional types with time since fire lead to patterns of 13C-enrichment with increased forest age. Successional stage and species composition trajectory dictated the composition of heterotrophic respiration with more 13C-enriched values found in dry/cold coniferous areas. Burn severity and successional state largely determined the distribution and abundance of plant functional types which dictated the δ13C values of organic pools and fluxes in the ecosystems. These results suggest that fire severity and frequency changes the carbon isotope composition of ecosystems and biosphere-atmosphere fluxes in ways that are predictable at local and regional scales by changing species composition and regrowth patterns.

Economy of Photosynthate Use in Nitrogen-fixing Legume Nodules: Observations on Two Contrasting Symbioses.

PubMed

Layzell, D B; Rainbird, R M; Atkins, C A; Pate, J S

1979-11-01

The economy of C use by root nodules was examined in two symbioses, Vigna unguiculata (L.) Walp. (cv. Caloona):Rhizobium CB756 and Lupinus albus L. (cv. Ultra):Rhizobium WU425 over a 2-week period in early vegetative growth. Plants were grown in minus N water culture with cuvettes attached to the nodulated zone of their primary roots for collection of evolved CO(2) and H(2). Increments in total plant N and in C and N of nodules, and C:N weight ratios of xylem and phloem exudates were studied by periodic sampling from the plant populations. Itemized budgets were constructed for the partitioning and utilization of C in the two species. For each milligram N fixed and assimilated by the cowpea association, 1.54 +/- 0.26 (standard error) milligrams C as CO(2) and negligible H(2) were evolved and 3.11 milligrams of translocated C utilized by the nodules. Comparable values for nodules of the lupin association were 3.64 +/- 0.28 milligrams C as CO(2), 0.22 +/- 0.05 milligrams H(2), and 6.58 milligrams C. More efficient use of C by cowpea nodules was due to a lesser requirement of C for synthesis of exported N compounds, a smaller allocation of C to nodule dry matter, and a lower evolution of CO(2). The activity of phosphoenolpyruvate carboxylase in nodule extracts and the rate of (14)CO(2) fixation by detached nodules were greater for the cowpea symbiosis (0.56 +/- 0.06 and 0.22 milligrams C as CO(2) fixed per gram fresh weight per hour, respectively) than for the lupin 0.06 +/- 0.02 and 0.01 milligrams C as CO(2) fixed per gram fresh weight per hour. The significance of the data was discussed in relation to current information on theoretical costs of nitrogenase functioning and associated nodule processes.

SU-F-T-10: Validation of ELP Dosimetry Using PRESAGE Dosimeter: Feasibility Test and Practical Considerations

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

Lambson, K; Lafata, K; Miles, D

Purpose: To validate the use of a PRESAGE dosimeter as a method to quantitatively measure dose distributions of injectable brachytherapy based on elastin-like polypeptide (ELP) nanoparticles. PRESAGE is a solid, transparent polyurethane-based dosimeter whose dose is proportional to a change in optical density, making it useful for visualizing the dose from a radionuclide-tagged-ELP injection. Methods: A PRESAGE dosimeter was designed to simulate an ELP injection. To calibrate, cuvette samples from the batch of PRESAGE were exposed to varying levels of radiation from 0–35.9Gy applied via a linear accelerator, then placed into a spectrophotometer to obtain the optical density change asmore » a function of dose. A pre-optical-CT scan was acquired of the phantom to obtain a baseline tomographic optical density. A 1cc saline solution of I-125 tagged-ELP with and activity concentration of 1mCi/cc was injected into the phantom and left for five days. After five days, the ELP was removed and the cavity cleaned of all remaining radioactive material. Post tomographic optical images were acquired to obtain a differential optical density dataset. Results: Initial results after the 5-day exposure revealed an opaque white film that resembled the volume of the ELP solution injected into the phantom. We think this is possibly due to the saline solution diffusing into the PRESAGE and causing a change in the index of refraction at this shallow depth. Therefore, initially the optical scanner yielded inconclusive results. After several more days, the saline seemed to have evaporated out of the injection site and the ELP dose distribution was visible via color change in the dosimeter. Conclusion: We have created the first experimental design to measure the dose distribution of I-125-tagged-ELP. The PRESAGE formulation proves to be a feasible option for such measurements. Future experimental measurements need to be obtained to further characterize ELP dosimetry.« less

Near-Infrared Spectroscopy Using a Supercontinuum Laser: Application to Long Wavelength Transmission Spectra of Barley Endosperm and Oil.

PubMed

Ringsted, Tine; Dupont, Sune; Ramsay, Jacob; Jespersen, Birthe Møller; Sørensen, Klavs Martin; Keiding, Søren Rud; Engelsen, Søren Balling

2016-07-01

The supercontinuum laser is a new type of light source, which combines the collimation and intensity of a laser with the broad spectral region of a lamp. Using such a source therefore makes it possible to focus the light onto small sample areas without losing intensity and thus facilitate either rapid or high-intensity measurements. Single seed transmission analysis in the long wavelength (LW) near-infrared (NIR) region is one area that might benefit from a brighter light source such as the supercontinuum laser. This study is aimed at building an experimental spectrometer consisting of a supercontinuum laser source and a dispersive monochromator in order to investigate its capability to measure the barley endosperm using transmission experiments in the LW NIR region. So far, barley and wheat seeds have only been studied using NIR transmission in the short wavelength region up to 1100 nm. However, the region in the range of 2260-2380 nm has previously shown to be particularly useful in differentiating barley phenotypes using NIR spectroscopy in reflectance mode. In the present study, 350 seeds (consisting of 70 seeds from each of five barley genotypes) in 1 mm slices were measured by NIR transmission in the range of 2235-2381 nm and oils from the same five barley genotypes were measured in a cuvette with a 1 mm path length in the range of 2003-2497 nm. The spectra of the barley seeds could be classified according to genotypes by principal component analysis; and spectral covariances with reference analysis of moisture, β-glucan, starch, protein and lipid were established. The spectral variations of the barley oils were compared to the fatty acid compositions as measured using gas chromotography-mass spectrometry (GC-MS). © The Author(s) 2016.

Investigation of the influence of liquid surface films on O3 and PAN deposition to plant leaves coated with organic/inorganic solution

NASA Astrophysics Data System (ADS)

Sun, Shang; Moravek, Alexander; Trebs, Ivonne; Kesselmeier, Jürgen; Sörgel, Matthias

2016-12-01

This study investigates the influence of leaf surface water films on the deposition of ozone (O3) and peroxyacetyl nitrate (PAN) under controlled laboratory conditions. A twin-cuvette system was used to simulate environmental variables. We observed a clear correlation between the O3 deposition on plants (Quercus ilex) and the relative humidity (RH) under both light and dark conditions. During the light period the observed increase of the O3 deposition was mainly attributed to the opening of leaf stomata, while during the absence of light the liquid surface films were the reason for O3 deposition. This finding was supported by experimentally induced stomatal closure by the infiltration of abscisic acid. In the case of PAN, no relationship with RH was found during the dark period, which indicates that the nonstomatal deposition of PAN is not affected by the liquid surface films. Consequently, the ratio of the O3 and PAN deposition velocities is not constant when relative humidity changes, which is in contrast to assumptions made in many models. The flux partitioning ratio between nonstomatal and stomatal depositions as well as between nonstomatal and total depositions was found to be Rnsto/sto = 0.21-0.40, Rnsto/tot = 0.18-0.30 for O3 and Rnsto/sto = 0.26-0.29, Rnsto/tot = 0.21-0.23 for PAN. Furthermore, we demonstrate that the formation of the liquid surface film on leaves and the nonstomatal O3 deposition are depending on the chemical composition of the particles deposited on the leaf cuticles as proposed previously.

Diurnal periodicity of assimilate transport shapes resource allocation and whole-plant carbon balance.

PubMed

Brauner, Katrin; Birami, Benjamin; Brauner, Horst A; Heyer, Arnd G

2018-06-01

Whole-plant carbon balance comprises diurnal fluctuations of photosynthetic carbon gain and respiratory losses, as well as partitioning of assimilates between phototrophic and heterotrophic organs. Because it is difficult to access, the root system is frequently neglected in growth models, or its metabolism is rated based on generalizations from other organs. Here, whole-plant cuvettes were used for investigating total-plant carbon exchange with the environment over full diurnal cycles. Dynamics of primary metabolism and diurnally resolved phloem exudation profiles, as proxy of assimilate transport, were combined to obtain a full picture of resource allocation. This uncovered a strong impact of periodicity of inter-organ transport on the efficiency of carbon gain. While a sinusoidal fluctuation of the transport rate, with minor diel deflections, minimized respiratory losses in Arabidopsis wild-type plants, triangular or rectangular patterns of transport, found in mutants defective in either starch or sucrose metabolism, increased root respiration at the end or beginning of the day, respectively. Power spectral density and cross-correlation analysis revealed that only the rate of starch synthesis was strictly correlated to the rate of net photosynthesis in wild-type, while in a sucrose-phosphate synthase mutant (spsa1), this applied also to carboxylate synthesis, serving as an alternative carbon pool. In the starchless mutant of plastidial phospho-gluco mutase (pgm), none of these rates, but concentrations of sucrose and glucose in the root, followed the pattern of photosynthesis, indicating direct transduction of shoot sugar levels to the root. The results demonstrate that starch metabolism alone is insufficient to buffer diurnal fluctuations of carbon exchange. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.

Changes in protein expression of U937 and Jurkat cells exposed to nanosecond pulsed electric fields

NASA Astrophysics Data System (ADS)

Moen, Erick K.; Roth, Caleb C.; Cerna, Caesar; Estalck, Larry; Wilmink, Gerald; Ibey, Bennett L.

2013-02-01

Application of nanosecond pulsed electric fields (nsPEF) to various biological cell lines has been to shown to cause many diverse effects, including poration of the plasma membrane, depolarization of the mitochondrial membrane, blebbing, apoptosis, and intracellular calcium bursts. The underlying mechanism(s) responsible for these diverse responses are poorly understood. Of specific interest in this paper are the long-term effects of nsPEF on cellular processes, including the regulation of genes and production of proteins. Previous studies have reported transient activation of select signaling pathways involving mitogen-activated protein kinases (MAPKs), protein phosphorylation and downstream gene expression following nsPEF application. We hypothesize that nsPEF represents a unique stimulus that could be used to externally modulate cellular processes. To validate our hypothesis, we performed a series of cuvette-based exposures at 10 and 600ns pulse widths using a custom Blumlien line pulser system. We measured acute changes in the plasma membrane structure using flow cytometry by tracking phosphatidylserine externalization via FITC-Annexin V labeling and poration via propidium iodide uptake. We then compared these results to viability of the cells at 24 hours post exposure using MTT assay and changes in the MAPK family of proteins at 8 hours post-exposure using Luminex assay. By comparing exposures at 10 and 600ns duration, we found that most MAPK family-protein expression increased in Jurkat and U937 cell lines following exposure and compared well with drops in viability and changes in plasma membrane asymmetry. What proved interesting is that some MAPK family proteins (e.g. p53, STAT1), were expressed in one cell line, but not the other. This difference may point to an underlying mechanism for observed difference in cellular sensitivity to nsPEFinduced stresses.

A universal fluorogenic switch for Fe(ii) ion based on N-oxide chemistry permits the visualization of intracellular redox equilibrium shift towards labile iron in hypoxic tumor cells.

PubMed

Hirayama, Tasuku; Tsuboi, Hitomi; Niwa, Masato; Miki, Ayaji; Kadota, Satoki; Ikeshita, Yukie; Okuda, Kensuke; Nagasawa, Hideko

2017-07-01

Iron (Fe) species play a number of biologically and pathologically important roles. In particular, iron is a key element in oxygen sensing in living tissue where its metabolism is intimately linked with oxygen metabolism. Regulation of redox balance of labile iron species to prevent the generation of iron-catalyzed reactive oxygen species (ROS) is critical to survival. However, studies on the redox homeostasis of iron species are challenging because of a lack of a redox-state-specific detection method for iron, in particular, labile Fe 2+ . In this study, a universal fluorogenic switching system is established, which is responsive to Fe 2+ ion based on a unique N-oxide chemistry in which dialkylarylamine N-oxide is selectively deoxygenized by Fe 2+ to generate various fluorescent probes of Fe 2+ -CoNox-1 (blue), FluNox-1 (green), and SiRhoNox-1 (red). All the probes exhibited fluorescence enhancement against Fe 2+ with high selectivity both in cuvette and in living cells. Among the probes, SiRhoNox-1 showed an excellent fluorescence response with respect to both reaction rate and off/on signal contrast. Imaging studies were performed showing the intracellular redox equilibrium shift towards labile iron in response to reduced oxygen tension in living cells and 3D tumor spheroids using SiRhoNox-1, and it was found that the hypoxia induction of labile Fe 2+ is independent of iron uptake, hypoxia-induced signaling, and hypoxia-activated enzymes. The present studies demonstrate the feasibility of developing sensitive and specific fluorescent probes for Fe 2+ with refined photophysical characteristics that enable their broad application in the study of iron in various physiological and pathological conditions.

Investigation of optical and hydrodynamic processes initiated in biological tissues and liquids under the action of high-power pulses of 1.54 μm laser radiation

NASA Astrophysics Data System (ADS)

Belikov, Andrey V.; Fomicheva, Yana Yu.; Gagarskiy, Sergey V.; Sergeev, Andrey N.; Smirnov, Sergey N.; Zagorulko, Alexey M.

2018-04-01

The results of strobe-photographic study of steam-gas cavities formation in a bulk of saline as a result of high-power Yb,Er:Glass laser pulses impact are presented. The data on dynamics of laser pulse transmission through the laserproduced steam-gas cavity for different values of the distance h between the fiber end and the cuvette bottom (quartz plate) are presented. It was observed that the steam-gas cavity might be used for effective non-contact delivery of laser radiation to the submerged target: transmission value at maximum steam-gas cavity size reached 0.87 for h = 0.5 mm. The influence of steam-gas cavities parameters on ablation efficiency of eye lens destruction in vitro is also discussed. The ablation of cataract eye lens in liquid environment is more effective than in air. The efficiency of eye lens ablation decreases with the increase of h . The maximal values of ablation efficiency (2.14·10-3 mm3/pulse) were obtained in the case of underwater ablation at h = 0 mm.

Isoprene emission rates and fluxes measured above a Mediterranean oak ( Quercus pubescens) forest

NASA Astrophysics Data System (ADS)

Simon, V.; Dumergues, L.; Bouchou, P.; Torres, L.; Lopez, A.

2005-03-01

The present work, carried out as part of the European fiEld experimentS to COnstrain Models of atmospheric Pollution and Transport of Emissions project (ESCOMPTE), brings a new contribution to the inventory of the main natural hydrocarbons sources that are liable to participate in the production of ozone. The measurement campaign was conducted in Montmeyan, a site close to Marseilles (France), with the aim of quantifying the terpenic emission pattern and the behaviour of Quercus pubescens, an important Mediterranean tree species. Biogenic emissions by Q. pubescens were determined by the enclosure of an intact branch of this tree in a Teflon cuvette. The total monoterpenic emission rates thus recorded were found to reach maximum values ranged between 40 and 350 μg g Dry Weight-1 h -1. Emissions were correlated strongly with leaf temperature and Photosynthetic Active Radiation (PAR). The fluxes were also determined by extrapolating the results of the enclosure method and by using aerodynamic gradient method. They reach around 73 mg m -2 h -1 with the first method and 55 mg m -2 h -1 with the second one. The obtained values fit with a maximal ratio of 2.

Contribution of planktonic and benthic food sources to the diet of the reef-forming vermetid gastropod Dendropoma petraeum in the western Mediterranean

NASA Astrophysics Data System (ADS)

Vizzini, Salvatrice; Colombo, Francesca; Costa, Valentina; Mazzola, Antonio

2012-01-01

In the Mediterranean Sea, the vermetid Dendropoma petraeum (Monterosato, 1884) forms highly biodiverse reefs that have received increasing attention in recent years although very little is known about the food habit of this species. The main goal of this study was to describe the trophic role of planktonic and benthic food sources for D. petraeum. Specimens from three morphological zones of the reef (inner edge, cuvette and outer edge) at two sites with different wave exposure along the north-western coast of Sicily (Italy; western Mediterranean) were compared for δ 13C and δ 15N. Isotopic determinations were also carried out on potential food sources identified in epilithon, reef macroalgae and suspended particulate organic matter. δ 13C for D. petraeum showed significantly more depleted values in the more exposed conditions (i.e. the site with higher wave exposure and outer edge of the reef), while δ 15N did not differ appreciably. These results suggest greater exploitation of benthic sources in the sheltered than in the exposed site and reveal diet shift and trophic flexibility at a small spatial scale for the reef-former D. petraeum.

Quantum dynamics of nuclear spins and spin relaxation in organic semiconductors

DOE PAGES

Mkhitaryan, V. V.; Dobrovitski, V. V.

2017-06-12

3D printing of materials with active functional groups can provide custom-designed structures that promote chemical conversions. Herein, catalytically active architectures were produced by photopolymerizing bifunctional molecules using a commercial stereolithographic 3D printer. Functionalities in the monomers included a polymerizable vinyl group to assemble the 3D structures and a secondary group to provide them with active sites. The 3D-printed architectures containing accessible carboxylic acid, amine, and copper carboxylate functionalities were catalytically active for the Mannich, aldol, and Huisgen cycloaddition reactions, respectively. The functional groups in the 3D-printed structures were also amenable to post-printing chemical modification. As proof of principle, chemically activemore » cuvette adaptors were 3D printed and used to measure in situ the kinetics of a heterogeneously catalyzed Mannich reaction in a conventional solution spectrophotometer. In addition, 3D-printed millifluidic devices with catalytically active copper carboxylate complexes were used to promote azide-alkyne cycloaddition under flow conditions. The importance of controlling the 3D architecture of the millifluidic devices was evidenced by enhancing reaction conversion upon increasing the complexity of the 3D prints.« less

In vivo near infrared (NIRS) sensor attachment using fibrin bioadhesive

NASA Astrophysics Data System (ADS)

Macnab, Andrew; Pagano, Roberto; Kwon, Brian; Dumont, Guy; Shadgan, Babak

2018-02-01

Background: `Tisseel' (Baxter Healthcare, Deerfield, IL) is a fibrin-based sealant that is commonly used during spine surgery to augment dural repairs. We wish to intra-operatively secure a near infrared spectroscopy (NIRS) sensor to the dura in order to monitor the tissue hemodynamics of the underlying spinal cord. To determine if `Tisseel' sealant adversely attenuates NIR photon transmission. Methods: We investigated `Tisseel' in both an in vitro and in vivo paradigm. For in vitro testing, we used a 1 mm pathlength cuvette containing either air or `Tisseel' interposed between a NIR light source (760 and 850 nm) and a photodiode detector and compared transmittance. For in vivo testing, a continuous wave (760 and 850 nm) spatiallyresolved NIRS device was placed over the triceps muscle using either conventional skin apposition (overlying adhesive bandage) or bioadhesion with `Tisseel'. Raw optical data and tissue saturation index (TSI%) collected at rest were compared. Results: In-vitro NIR light absorption by `Tisseel' was very high, with transmittance reduced by 95% compared to air. In-vivo muscle TSI% values were 80% with conventional attachment and 20% using fibrin glue. Conclusion: The optical properties of `Tisseel' significantly attenuate NIR light during in-vitro transmittance and critically compromise photon transmission in-vivo.

Nanopaper as an Optical Sensing Platform.

PubMed

Morales-Narváez, Eden; Golmohammadi, Hamed; Naghdi, Tina; Yousefi, Hossein; Kostiv, Uliana; Horák, Daniel; Pourreza, Nahid; Merkoçi, Arben

2015-07-28

Bacterial cellulose nanopaper (BC) is a multifunctional material known for numerous desirable properties: sustainability, biocompatibility, biodegradability, optical transparency, thermal properties, flexibility, high mechanical strength, hydrophilicity, high porosity, broad chemical-modification capabilities and high surface area. Herein, we report various nanopaper-based optical sensing platforms and describe how they can be tuned, using nanomaterials, to exhibit plasmonic or photoluminescent properties that can be exploited for sensing applications. We also describe several nanopaper configurations, including cuvettes, plates and spots that we printed or punched on BC. The platforms include a colorimetric-based sensor based on nanopaper containing embedded silver and gold nanoparticles; a photoluminescent-based sensor, comprising CdSe@ZnS quantum dots conjugated to nanopaper; and a potential up-conversion sensing platform constructed from nanopaper functionalized with NaYF4:Yb(3+)@Er(3+)&SiO2 nanoparticles. We have explored modulation of the plasmonic or photoluminescent properties of these platforms using various model biologically relevant analytes. Moreover, we prove that BC is and advantageous preconcentration platform that facilitates the analysis of small volumes of optically active materials (∼4 μL). We are confident that these platforms will pave the way to optical (bio)sensors or theranostic devices that are simple, transparent, flexible, disposable, lightweight, miniaturized and perhaps wearable.

Aerobic Methane Generation From Plants (AMP)? Yes, Mostly!

NASA Astrophysics Data System (ADS)

Whiticar, M. J.; Ednie, A. C.

2007-12-01

In 2006, Keppler et al. (K) published an intriguing and revolutionary idea that aerobic methane is produced in plants (AMP) and released to the atmosphere. Their initial scaling calculations estimated the amount of AMP fluxing from living plants to range from 62-236 Tg/y and 1-7 Tg/y for plant litter. Houweling et al. (2006) (H) refined this flux to ca. 85 Tg/y PIH and 125 Tg/y present day. More recently, Dueck et al. (2007) (D) challenged the claim of AMP from intact plants. Their experiments cited "...No evidence for substantial aerobic methane emission by terrestrial plants..." (max. 0.4 ng/g h-1). Due to the significance of AMP in understanding present and palaeo-atmospheric budgets (e.g., Whiticar and Schaefer, 2007), we conducted a wide range of experiments to confirm or refute the existence and magnitude of AMP. For explanation, experiments of K were time-series batch samples measured by gas chromatography on purged and ambient samples, whereas D used continuous-flow cuvettes and measured by optical PAS with time series single injections. Our longer-term experiments with corn, wheat, tomato, red cedar, chestnut, moss and lichen (3-97 h, 32 °C) used a plant chamber, flow-through system with a GYRO, an optical spectrometer that enables continuous 1 Hz CH4 measurements with a precision of ca. 1 ppbv. We conducted over 100 chamber experiments on sterilized and non-sterilized (Cs-137 radiation) samples of: 1) intact living plants (IP), 2) fresh leaves (FL) and 3) dried leaves (DL); under both 1) high and 2) low light conditions (HL, LL), and with 1) ambient CH4 (AM, ca. 1.92 ppmv) and 2) purged methane (PM, 10 and 96 ppbv) levels. Our results demonstrate that IP-AMs have CH4 flux rates of 0.74-3.48 ng/g h-1. In contrast, IP-PMs show intense CH4 uptake rates of -28.5 to -57.9 ng/g h-1 (substantially different than K's reported emissions of 12-370 ng/g h-1 values). Our FL-AM-LL have CH4 flux rates of 0.36-2.05 ng/g h-1, whereas FL-AM-HL have significant CH4 generation of 0.27 to 12.7 ng/g h-1 (substantially higher than K's max of 3 ng/g h-1). FL-PM emissions are low (ca. 1 ng/g h-1). DL CH4 release is also low ranging from LL of 0.33 to HL of 3.37 ng/g h-1. Interestingly, our Cs-irradiated FL have increasingly higher CH4 emission rates with higher radiation dosages. We do not attempt to extrapolate our AMP laboratory experiments to global scales, nor make any physiological, biochemical or mechanistic claims. However at this point our work does indeed confirm that AMP is indeed operative and significant under certain conditions. The magnitude of our small scale, laboratory, AMP emission experiments is consistent with the earlier claims of K and H. We have, to some degree, emulated the experimental designs of both K and D. We remain intrigued by the findings, yet uncertain, if not puzzled, by the process and the discrepancies between groups.

A bio-telemetric device for measurement of left ventricular pressure-volume loops using the admittance technique in conscious, ambulatory rats.

PubMed

Raghavan, Karthik; Feldman, Marc D; Porterfield, John E; Larson, Erik R; Jenkins, J Travis; Escobedo, Daniel; Pearce, John A; Valvano, Jonathan W

2011-06-01

This paper presents the design, construction and testing of a device to measure pressure-volume loops in the left ventricle of conscious, ambulatory rats. Pressure is measured with a standard sensor, but volume is derived from data collected from a tetrapolar electrode catheter using a novel admittance technique. There are two main advantages of the admittance technique to measure volume. First, the contribution from the adjacent muscle can be instantaneously removed. Second, the admittance technique incorporates the nonlinear relationship between the electric field generated by the catheter and the blood volume. A low power instrument weighing 27 g was designed, which takes pressure-volume loops every 2 min and runs for 24 h. Pressure-volume data are transmitted wirelessly to a base station. The device was first validated on 13 rats with an acute preparation with 2D echocardiography used to measure true volume. From an accuracy standpoint, the admittance technique is superior to both the conductance technique calibrated with hypertonic saline injections, and calibrated with cuvettes. The device was then tested on six rats with 24 h chronic preparation. Stability of animal preparation and careful calibration are important factors affecting the success of the device.

Bio-telemetric device for measurement of left ventricular pressure-volume loops using the admittance technique in conscious, ambulatory rats

PubMed Central

Raghavan, Karthik; Feldman, Marc D; Porterfield, John E; Larson, Erik R; Jenkins, J Travis; Escobedo, Daniel; Pearce, John A

2011-01-01

This paper presents the design, construction and testing of a device to measure pressure volume loops in the left ventricle of conscious, ambulatory rats. Pressure is measured with a standard sensor, but volume is derived from data collected from a tetrapolar electrode catheter using a novel admittance technique. There are two main advantages of the admittance technique to measure volume. First, the contribution from the adjacent muscle can be instantaneously removed. Second, the admittance technique incorporates the nonlinear relationship between the electric field generated by the catheter and the blood volume. A low power instrument weighing 27 g was designed, which takes pressure-volume loops every 2 minutes and runs for 24 hours. Pressure-volume data are transmitted wirelessly to a base station. The device was first validated in thirteen rats with an acute preparation with 2-D echocardiography used to measure true volume. From an accuracy standpoint, the admittance technique is superior to both the conductance technique calibrated with hypertonic saline injections, and calibrated with cuvettes. The device was then tested in six rats with a 24-hour chronic preparation. Stability of the animal preparation and careful calibration are important factors affecting the success of the device. PMID:21606560

Correlating measured transient temperature rises with damage rate processes in cultured cells

NASA Astrophysics Data System (ADS)

Denton, Michael L.; Tijerina, Amanda J.; Gonzalez, Cherry C.; Gamboa, B. Giovana; Noojin, Gary D.; Ahmed, Elharith M.; Rickman, John M.; Dyer, Phillip H.; Rockwell, Benjamin A.

2017-02-01

Thermal damage rate processes in biological tissues are usually characterized by a kinetics approach. This stems from experimental data that show how the transformation of a specified biological property of cells or biomolecule (plating efficiency for viability, change in birefringence, tensile strength, etc.) is dependent upon both time and temperature. Here, two disparate approaches were used to study thermal damage rate processes in cultured retinal pigment epithelial cells. Laser exposure (photothermal) parameters included 2-μm laser exposure of non-pigmented cells and 532-nm exposures of cells possessing a variety of melanosome particle densities. Photothermal experiments used a mid-IR camera to record temperature histories with spatial resolution of about 8 μm, while fluorescence microscopy of the cell monolayers identified threshold damage at the boundary between live and dead cells. Photothermal exposure durations ranged from 0.05-20 s, and the effects of varying ambient temperature were investigated. Temperature during heat transfer using a water-jacketed cuvette was recorded with a fast microthermister, while damage and viability of the suspended cells were determined as percentages. Exposure durations for the heat transfer experiments ranged from 50- 60 s. Empirically-determined kinetic parameters for the two heating methods were compared with each other, and with values found in the literature.

Final Progress Report for Grant Number DE-SC0007229

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

Blake, Robert

2016-08-18

We exploited a novel spectrophotometer where the cuvette is a reflecting cavity completely filled with an absorbing suspension of live, intact bacteria to monitor the in situ absorbance changes in bacteria as they respired aerobically on soluble ferrous ions. Our prior observations suggested the following hypothesis: acidophilic bacteria that belong to different phyla express different types of electron transfer proteins to respire on extracellular iron. We tested this hypothesis using six different organisms that represented each of the six phyla of microorganisms that respire aerobically on iron. Each of these six organisms expressed spectrally different biomolecules that were redox-active duringmore » aerobic respiration on iron. In all six cases, compelling kinetic evidence was collected to indicate that the biomolecules in question were obligatory intermediates in their respective respiratory chains. Additional experiments with intact Acidithiobacillus ferrooxidans revealed that the crowded electron transport proteins in this organism’s periplasm constituted a semi-conducting medium where the network of protein interactions functioned in a concerted fashion as a single ensemble. Thus the molecular oxygen-dependent oxidation of the multi-center respiratory chain occurred with a single macroscopic rate constant, regardless of the proteins’ individual redox potentials or their putative positions in the aerobic iron respiratory chain.« less

Rapid and label-free bioanalytical method of alpha fetoprotein detection using LSPR chip

NASA Astrophysics Data System (ADS)

Kim, Dongjoo; Kim, Jinwoon; Kwak, Cheol Hwan; Heo, Nam Su; Oh, Seo Yeong; Lee, Hoomin; Lee, Go-Woon; Vilian, A. T. Ezhil; Han, Young-Kyu; Kim, Woo-Sik; Kim, Gi-bum; Kwon, Soonjo; Huh, Yun Suk

2017-07-01

Alpha fetoprotein (AFP) is a cancer marker, particularly for hepatocellular carcinoma. Normal levels of AFP are less than 20 ng/mL; however, its levels can reach more than 400 ng/mL in patients with HCC. Enzyme linked immunosorbent assay (ELISA) and radioimmunoassay (RIA) have been employed for clinical diagnosis of AFP; however, these methods are time consuming and labor intensive. In this study, we developed a localized surface plasmon resonance (LSPR) based biosensor for simple and rapid detection of AFP. This biosensor consists of a UV-Vis spectrometer, a cuvette cell, and a biosensor chip nanopatterned with gold nanoparticles (AuNPs). In our LSPR biosensor, binding of AFP to the surface of the sensor chip led to an increasing magnitude of the LSPR signals, which was measured by an ultraviolet-visible (UV-Vis) spectrometer. Our LSPR biosensor showed sufficient detectability of AFP at concentrations of 1 ng/mL to 1 μg/mL. Moreover, the overall procedure for detection of AFP was completed within 20 min. This biosensor could also be utilized for a point of care test (POCT) by employing a portable UV-Vis spectrometer. Owing to the simplicity and rapidity of the detection process, our LSPR biosensor is expected to replace traditional diagnostic methods for the early detection of diseases.

Immunogold Nanoparticles for Rapid Plasmonic Detection of C. sakazakii.

PubMed

Aly, Mohamed A; Domig, Konrad J; Kneifel, Wolfgang; Reimhult, Erik

2018-06-25

Cronobacter sakazakii is a foodborne pathogen that can cause a rare, septicemia, life-threatening meningitis, and necrotizing enterocolitis in infants. In general, standard methods for pathogen detection rely on culture, plating, colony counting and polymerase chain reaction DNA-sequencing for identification, which are time, equipment and skill demanding. Recently, nanoparticle- and surface-based immunoassays have increasingly been explored for pathogen detection. We investigate the functionalization of gold nanoparticles optimized for irreversible and specific binding to C. sakazakii and their use for spectroscopic detection of the pathogen. We demonstrate how 40-nm gold nanoparticles grafted with a poly(ethylene glycol) brush and functionalized with polyclonal antibodies raised against C. sakazakii can be used to specifically target C. sakazakii . The strong extinction peak of the Au nanoparticle plasmon polariton resonance in the optical range is used as a label for detection of the pathogens. Individual binding of the nanoparticles to the C. sakazakii surface is also verified by transmission electron microscopy. We show that a high degree of surface functionalization with anti- C. sakazakii optimizes the detection and leads to a detection limit as low as 10 CFU/mL within 2 h using a simple cuvette-based UV-Vis spectrometric readout that has great potential for further optimization.

Multimodal biopanning of T7 phage-displayed peptides reveals angiomotin as a potential receptor of the anti-angiogenic macrolide Roxithromycin.

PubMed

Takakusagi, Kaori; Takakusagi, Yoichi; Suzuki, Takahiro; Toizaki, Aya; Suzuki, Aiko; Kawakatsu, Yaichi; Watanabe, Madoka; Saito, Yukihiro; Fukuda, Ryushi; Nakazaki, Atsuo; Kobayashi, Susumu; Sakaguchi, Kengo; Sugawara, Fumio

2015-01-27

Roxithromycin (RXM) is a semi-synthetic fourteen-membered macrolide antibiotic that shows anti-angiogenic activity in solid tumors. In the present study, we conducted biopanning of T7 phage-displayed peptides either on a 96-well formatted microplate, a flow injection-type quartz-crystal microbalance (QCM) biosensor, or a cuvette-type QCM. RXM-selected peptides of different sequence, length and number were obtained from each mode of screening. Subsequent bioinformatics analysis of the RXM-selected peptides consistently gave positive scores for the extracellular domain (E458-T596) of angiomotin (Amot), indicating that this may comprise a binding region for RXM. Bead pull down assay and QCM analysis confirmed that RXM directly interacts with Amot via the screen-guided region, which also corresponds to the binding site for the endogenous anti-angiogenic inhibitor angiostatin (Anst). Thus, multimodal biopanning of T7PD revealed that RXM binds to the extracellular domain on Amot as a common binding site with Anst, leading to inhibition of angiogenesis-dependent tumor growth and metastasis. These data might explain the molecular basis underlying the mechanism of action for the anti-angiogenic activity of RXM. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

FRET-Aptamer Assays for Bone Marker Assessment, C-Telopeptide, Creatinine, and Vitamin D

NASA Technical Reports Server (NTRS)

Bruno, John G.

2013-01-01

Astronauts lose 1.0 to 1.5% of their bone mass per month on long-duration spaceflights. NASA wishes to monitor the bone loss onboard spacecraft to develop nutritional and exercise countermeasures, and make adjustments during long space missions. On Earth, the same technology could be used to monitor osteoporosis and its therapy. Aptamers bind to targets against which they are developed, much like antibodies. However, aptamers do not require animal hosts or cell culture and are therefore easier, faster, and less expensive to produce. In addition, aptamers sometimes exhibit greater affinity and specificity vs. comparable antibodies. In this work, fluorescent dyes and quenchers were added to the aptamers to enable pushbutton, one-step, bind-and-detect fluorescence resonance energy transfer (FRET) assays or tests that can be freeze-dried, rehydrated with body fluids, and used to quantitate bone loss of vitamin D levels with a handheld fluorometer in the spacecraft environment. This work generated specific, rapid, one-step FRET assays for the bone loss marker C-telopeptide (CTx) when extracted from urine, creatinine from urine, and vitamin D congeners in diluted serum. The assays were quantified in nanograms/mL using a handheld fluorometer connected to a laptop computer to convert the raw fluorescence values into concentrations of each analyte according to linear standard curves. DNA aptamers were selected and amplified for several rounds against a 26- amino acid form of CTx, creatinine, and vitamin D. The commonalities between loop structures were studied, and several common loop structures were converted into aptamer beacons with a fluorophore and quencher on each end. In theory, when the aptamer beacon binds its cognate target (CTx bone peptide, creatinine, or vitamin D), it is forced open and no longer quenched, so it gives off fluorescent light (when excited) in proportion to the amount of target present in a sample. This proportional increase in fluorescence is called a "lights on" FRET response. The vitamin D aptamer beacon gives a "lights off" or inversely proportional fluorescence response to the amount of vitamin D present in diluted serum. These FRET-aptamer assays are rapid (<30 minutes), sensitive (low ng/mL detection limits), and quite easy to carry out (add sample, mix, and detect in the handheld reader). Benefits include the speed of the assays as well as the small amount of space taken up by the handheld reader and cuvette assays. The aptamer DNA sequences represent novel additional features of the existing (patent-pending) FRET-aptamer assay platform.

[Risk assessment of thrombotic events in patients with schizophrenia and schizoaffective disorder in the acute state: the 'fibrinodynamics' technology].

PubMed

Brusov, O S; Matveev, I A; Kirillov, P S; Faktor, M I; Karpova, N S; Vasilyeva, E F; Katasonov, A B; Zozulya, S A; Klushnik, T P

To assess the risk of thrombotic events in patients with schizophrenia and schizoaffective disorder based on 'fibrinodynamics' technology. A group of 76 women, including 38 with paranoid schizophrenia (F20.0), 18 with schizoaffective disorder (F25.1) in the acute stage, and 20 healthy controls, participated in the study. The technology includes the study of coagulation and fibrinolysis, Karmin author software, and calculation of peak time and hemostasis potential of spontaneous clots. Growth and lysis of fibrin clots were studied in plasma purified from platelets. All preanalytic procedures were conducted within 30 minutes after blood sampling. Blood serum was studied separately using the neuroimmunological test. Dynamic of brightness profiles of the clots was determined and a number of parameters (peak time and hemostasis potential of spontaneous clots) were calculated using the Karmin software. In patients with schizophrenia, the dynamic brightness profile of the clots has two peaks: the first peak is formed as a result of the growth and lysis of the clot initiated by the activator, the second peak is due to the growth and lysis of spontaneous clots in the volume of the measuring cuvette far from the activator. In healthy donors, the second peak under experimental conditions is absent. In the group of schizophrenic patients, a strong negative correlation is observed between the peak time of the second peak and the activity of leukocyte elastase (Spearman R = -0.75, p<0.0001), i.e. the greater the activity of elastase, the earlier the maximum of the second peak is formed and vice versa. In the control group, there is no such correlation. Evaluation of the potential of hemostasis of spontaneous clots showed that in 42% of schizophrenic patients this parameter is shifted above the norm, which indicates an increased risk of thrombosis of small brain arteries in these patients. The developed technology of 'fibrinodynamics' has a good potential for introduction into personalized medicine to identify increased risks of thrombosis of small cerebral vessels in patients with acute schizophrenia leading to the development of cognitive disorders and to control the normalization of hemostasis with antiplatelet or anticoagulant drugs.

[Clinical management of patients and deceased during the Ebola outbreak from October to December 2003 in Republic of Congo].

PubMed

Boumandouki, P; Formenty, P; Epelboin, A; Campbell, P; Atsangandoko, C; Allarangar, Y; Leroy, E M; Kone, M L; Molamou, A; Dinga-Longa, O; Salemo, A; Kounkou, R Y; Mombouli, V; Ibara, J R; Gaturuku, P; Nkunku, S; Lucht, A; Feldmann, H

2005-09-01

Outbreaks of Ebola virus hemorrhagic fever (EVHF) have been reported since 2001 in the Cuvette Ouest department, a forested area located in the Western North of Congo. At the end of October 2003 a new alarm came from this department which was quickly confirmed as being an epidemic of EVHF. The outbreak response was organized by the ministry of health with the assistance of an international team under the aegis of WHO. The case management of suspect cases was done in an isolation ward set up at the hospital; when patients refused to go to the ward for care they were isolated in their house according to a protocol "transmission risks reduction at home". Safe burials were performed by specialized teams which respected the major aspects of the funeral to allow the process of mourning of the families. An active surveillance system was set up in order to organize the detection of new cases and the follow-up of their contacts. A case definition was adopted. From October 11 to December 2, 2003, 35 cases including 29 deaths were reported, 16 cases were laboratory confirmed. The first four cases had been exposed to monkey meat (Cercopithecus nictitans). The epidemic spread was due to family transmission. The population interpretation of the disease, in particular questions around wizards and evil-minded persons, is a factor which must be taken into account by the medical teams during communication meetings for behavioral change of the populations. The case management of patient in isolation wards to prevent the transmission of the virus in the community remains the most effective means to dam up Ebola virus hemorrhagic fever outbreaks. The good perception by the community of the safe funerary procedures is an important aspect in the establishment of confidence relations with the local population.

Biogenic emissions from Pinus halepensis: a typical species of the Mediterranean area

NASA Astrophysics Data System (ADS)

Simon, V.; Dumergues, L.; Solignac, G.; Torres, L.

2005-03-01

Volatile organic compounds (VOCs) emissions by vegetation present in the Mediterranean area are not well known. They may contribute with anthropogenic VOC emissions to the tropospheric ozone formation that reaches important level in the European Mediterranean region. The present work, carried out as part of the European ESCOMPTE project «fiEld experimentS to COnstrain Models of atmospheric Pollution and Transport of Emissions», adds a new contribution to the inventory of the main natural hydrocarbons sources likely to participate in the ozone production. The corresponding measurement campaign was conducted in La Barben, a site close to Marseilles (France), with the aim to quantify the terpenic emission pattern and the behaviour of Pinus halepensis, an important Mediterranean species slightly studied. The determination of biogenic emissions from P. halepensis was done by the enclosure of an intact branch in a Teflon cuvette. Main emitted monoterpenes were β trans-ocimene and linalool. The total monoterpenic emission rates thus recorded were found to reach maximum values around 30 μg g dry weight-1 h -1. The normalized emission rates calculated at 30 °C and 1000 μmol m -2 s -1 with Guenther's algorithm was 14.76, 8.65 and 4.05 μg g dry weight-1 h -1, respectively, for the total monoterpenes, β trans-ocimene and linalool.

Laser streaming: Turning a laser beam into a flow of liquid

PubMed Central

Wang, Yanan; Zhang, Qiuhui; Zhu, Zhuan; Lin, Feng; Deng, Jiangdong; Ku, Geng; Dong, Suchuan; Song, Shuo; Alam, Md Kamrul; Liu, Dong; Wang, Zhiming; Bao, Jiming

2017-01-01

Transforming a laser beam into a mass flow has been a challenge both scientifically and technologically. We report the discovery of a new optofluidic principle and demonstrate the generation of a steady-state water flow by a pulsed laser beam through a glass window. To generate a flow or stream in the same path as the refracted laser beam in pure water from an arbitrary spot on the window, we first fill a glass cuvette with an aqueous solution of Au nanoparticles. A flow will emerge from the focused laser spot on the window after the laser is turned on for a few to tens of minutes; the flow remains after the colloidal solution is completely replaced by pure water. Microscopically, this transformation is made possible by an underlying plasmonic nanoparticle-decorated cavity, which is self-fabricated on the glass by nanoparticle-assisted laser etching and exhibits size and shape uniquely tailored to the incident beam profile. Hydrophone signals indicate that the flow is driven via acoustic streaming by a long-lasting ultrasound wave that is resonantly generated by the laser and the cavity through the photoacoustic effect. The principle of this light-driven flow via ultrasound, that is, photoacoustic streaming by coupling photoacoustics to acoustic streaming, is general and can be applied to any liquid, opening up new research and applications in optofluidics as well as traditional photoacoustics and acoustic streaming. PMID:28959726

Short-Term Effects of Carbon Dioxide on Carnation Callus Cell Respiration 1

PubMed Central

Palet, Artur; Ribas-Carbó, Miquel; Argilés, Josep M.; Azcón-Bieto, Joaquim

1991-01-01

The addition of potassium bicarbonate to the electrode cuvette immediately stimulated the rate of dark O2 uptake of photomixotrophic and heterotrophic carnation (Dianthus caryophyllus L.) callus, of Elodea canadensis (Michx) leaves, and of other plant tissues. This phenomenon occurred at pH values lower than 7.2 to 7.8, and the stimulation depended on the concentration of gaseous CO2 in the solution. These stimulatory responses lasted several minutes and then decreased, but additional bicarbonate or gaseous CO2 again stimulated respiration, suggesting a reversible effect. Carbonic anhydrase in the solution increased the stimulatory effect of potassium bicarbonate. The CO2/bicarbonate dependent stimulation of respiration did not occur in animal tissues such as rat diaphragm and isolated hepatocytes, and was inhibited by salicylhydroxamic acid in carnation callus cells and E. canadensis leaves. This suggested that the alternative oxidase was engaged during the stimulation in plant tissues. The cytochrome pathway was severely inhibited by CO2/bicarbonate either in the absence or in the presence of the uncoupler carbonylcyanide m-chlorophenyl hydrazone. The activity of cytochrome c oxidase of callus tissue homogenates was also inhibited by CO2/bicarbonate. The results suggested that high carbon dioxide levels (mainly free CO2) partially inhibited the cytochrome pathway (apparently at the oxidase level), and this block in electron transport elicited a large transient engagement of the alternative oxidase when present uninhibited. PMID:16668209

Optical coherence tomography and optical coherence domain reflectometry for deep brain stimulation probe guidance

NASA Astrophysics Data System (ADS)

Jeon, Sung W.; Shure, Mark A.; Baker, Kenneth B.; Chahlavi, Ali; Hatoum, Nagi; Turbay, Massud; Rollins, Andrew M.; Rezai, Ali R.; Huang, David

2005-04-01

Deep Brain Stimulation (DBS) is FDA-approved for the treatment of Parkinson's disease and essential tremor. Currently, placement of DBS leads is guided through a combination of anatomical targeting and intraoperative microelectrode recordings. The physiological mapping process requires several hours, and each pass of the microelectrode into the brain increases the risk of hemorrhage. Optical Coherence Domain Reflectometry (OCDR) in combination with current methodologies could reduce surgical time and increase accuracy and safety by providing data on structures some distance ahead of the probe. For this preliminary study, we scanned a rat brain in vitro using polarization-insensitive Optical Coherence Tomography (OCT). For accurate measurement of intensity and attenuation, polarization effects arising from tissue birefringence are removed by polarization diversity detection. A fresh rat brain was sectioned along the coronal plane and immersed in a 5 mm cuvette with saline solution. OCT images from a 1294 nm light source showed depth profiles up to 2 mm. Light intensity and attenuation rate distinguished various tissue structures such as hippocampus, cortex, external capsule, internal capsule, and optic tract. Attenuation coefficient is determined by linear fitting of the single scattering regime in averaged A-scans where Beer"s law is applicable. Histology showed very good correlation with OCT images. From the preliminary study using OCT, we conclude that OCDR is a promising approach for guiding DBS probe placement.

Laser streaming: Turning a laser beam into a flow of liquid.

PubMed

Wang, Yanan; Zhang, Qiuhui; Zhu, Zhuan; Lin, Feng; Deng, Jiangdong; Ku, Geng; Dong, Suchuan; Song, Shuo; Alam, Md Kamrul; Liu, Dong; Wang, Zhiming; Bao, Jiming

2017-09-01

Transforming a laser beam into a mass flow has been a challenge both scientifically and technologically. We report the discovery of a new optofluidic principle and demonstrate the generation of a steady-state water flow by a pulsed laser beam through a glass window. To generate a flow or stream in the same path as the refracted laser beam in pure water from an arbitrary spot on the window, we first fill a glass cuvette with an aqueous solution of Au nanoparticles. A flow will emerge from the focused laser spot on the window after the laser is turned on for a few to tens of minutes; the flow remains after the colloidal solution is completely replaced by pure water. Microscopically, this transformation is made possible by an underlying plasmonic nanoparticle-decorated cavity, which is self-fabricated on the glass by nanoparticle-assisted laser etching and exhibits size and shape uniquely tailored to the incident beam profile. Hydrophone signals indicate that the flow is driven via acoustic streaming by a long-lasting ultrasound wave that is resonantly generated by the laser and the cavity through the photoacoustic effect. The principle of this light-driven flow via ultrasound, that is, photoacoustic streaming by coupling photoacoustics to acoustic streaming, is general and can be applied to any liquid, opening up new research and applications in optofluidics as well as traditional photoacoustics and acoustic streaming.

A Novel Biomedical Device Utilizing Light Emitting Nano-Structures

NASA Technical Reports Server (NTRS)

Varaljay, Vanessa A.

2004-01-01

This paper will discuss the development of a novel biomedical detection device that will be used to detect microorganisms with the use of infrared fluorochrome polymers attached to antibodies in fluids such as water. The fluorochrome polymers emit light in the near inferred region (NIR), approximately 805 nm, when excited by an NIR laser at 778 nm. The device could remarkably change the way laboratory testing is done today. The testing process is usually performed on a time scale of days while our device will be able to detect microorganisms in minutes. This type of time efficient analysis is ideal for use aboard the International Space Station and the Space Shuttle (ISS/SS) and has many useful commercial applications, for instance at a water treatment plant and food processing plants. With more research and experimentation the testing might also one day be used to detect bacteria and viruses in complex fluids such as blood, which would revolutionize blood analysis as it is performed today. My contribution to the project has been to develop a process which will allow an antibody/fluorescent dye pair to be conjugated to a specific bacteria or virus and than to to be separated from a sample body of water for detection. The antibody being used in this experiment is anti beta galactosidase and its complement enzyme is beta galactosidase, a non harmful derivative of E. Coli. The anti beta galactosidase has been conjugated to the fluorochrome polymer, IRDye800, which emits at approximately 806 nm. The dye when excited by the NIR laser emits a signal which is detected by a spectrometer and then is read by state of the art computer software. The state-of-the-art process includes incubating the anti beta galactosidase and beta galactosidase in a phosphate buffer solution in a test tube, allowing the antibody to bind to specific sites on the enzyme. After the antibody is bound to the enzyme, it is centrifuged in specific filters that will allow free antibody to wash away and leave the antibody-enzyme complexes on top in solution for testing and analysis. This solution is pipetted into a cuvette, a special plastic test tube, which will then be excited by the laser. The signal read will tell US that an antibody is present and since it is bound to the enzyme, that the bacteria is also present.

Demonstration of the production of oxygen-centered free radicals during electrolysis using E.S.R. spin-trapping techniques: effects on cardiac function in the isolated rat heart.

PubMed

Lecour, S; Baouali, A B; Maupoil, V; Chahine, R; Abadie, C; Javouhey-Donzel, A; Rochette, L; Nadeau, R

1998-03-01

The present study was designed to identify the free radicals generated during the electrolysis of the solution used to perfuse isolated rat heart Langendorff preparations. The high reactivity and very short half-life of oxygen free radicals make their detection and identification difficult. A diamagnetic organic molecule (spin trap) can be used to react with a specific radical to produce a more stable secondary radical or "spin adduct" detected by electron spin resonance (ESR). Isovolumic left ventricular systolic pressure (LVSP) and left ventricular end diastolic pressure (LVEDP) were measured by a fluid-filled latex balloon inserted into the left ventricle. The coronary flow was measured by effluent collection. Electrolysis was performed with constant currents of 0.5, 1, 1.5, 3, 5, 7.5, and 10 mA generated by a Grass stimulator and applied to the perfusion solution for 1 min. A group of experiments was done using a 1.5 mA current and a Krebs-Henseleit (K-H) solution containing free radical scavengers (superoxide dismutase (SOD): 100 IU/ml or mannitol: 50 mM). Heart function rapidly declined in hearts perfused with K-H buffer that had been electrolyzed for 1 min. The addition of mannitol (50 mM) to the perfusion solution had no effect on baseline cardiac function before electrolysis while SOD (100 IU/ml) increased the coronary flow. However, SOD was more effective than the mannitol in protecting the heart against decreased of cardiac function, 5 min after the end of electrolysis. Samples of the K-H medium subjected to electrolysis were collected in cuvettes containing a final concentration of 125 mM 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and analyzed by spectroscopy. The ESR spectrum consisted of a quartet signal (hyperfine couplings aN = aH = 14.9 G) originating from the hydroxyl adduct signal, DMPO-OH. The intensity of the DMPO-OH signal remained stable during the 60 s of electrolysis and the quantity of free radicals induced by electrolysis was directly proportional to the intensity of the current. The addition of mannitol and SOD to the perfusate scavenged the hydroxyl radicals present in the solution, suggesting that both hydroxyl and superoxide radicals were formed during electrolysis.

Occupation of the cytochrome P450 substrate pocket by diverse compounds at general anesthesia concentrations.

PubMed

LaBella, F S; Stein, D; Queen, G

1998-10-02

Each of a diverse array of compounds, at concentrations reported to effect general anesthesia, when added to liver microsomes, forms a complex with cytochromes P450 to generate, with reference to a cuvette containing microsomes only, a characteristic absorbance-difference spectrum. This spectrum results from a change in the electron-spin state of the heme iron atom induced upon entry by the anesthetic molecule into the enzyme catalytic pocket. The difference spectrum, representing the anesthetic-P450 complex, is characteristic of substances that are substrates for the enzyme. For the group of compounds as a whole, the magnitudes of the absorbance-difference spectra vary only about twofold, although the anesthetic potencies vary by several orders of magnitude. The dissociation constants (Ks), calculated from absorbance data and representing affinities of the anesthetics for P450, agree closely with the respective EC50 (concentration that effects anesthesia in 50% of individuals) values, and with the respective Ki (concentration that inhibits P450 catalytic activities half-maximally) values reported by us previously. The absorbance complex resulting from the occupation of the catalytic pocket by endogenous substrates, androstenedione and arachidonic acid, is inhibited, competitively, by anesthetics. Occupation of and perturbation of the heme catalytic pocket by anesthetic, as monitored by the absorbance-difference spectrum, is rapidly reversible. The presumed in vivo consequences of perturbation by general anesthetics of heme proteins is suppression of the generation of chemical signals that determine cell sensitivity and response.

Spatial beam shaping for lowering the threshold energy for femtosecond laser pulse photodisruption

NASA Astrophysics Data System (ADS)

Hansen, Anja; Ripken, Tammo; Heisterkamp, Alexander

2011-10-01

High precision femtosecond laser surgery is achieved by focusing femtosecond (fs) laser pulses in transparent tissues to create an optical breakdown leading to tissue dissection through photodisruption. For moving applications in ophthalmology from corneal or lental applications in the anterior eye to vitreal or retinal surgery in the posterior eye the applied pulse energy needs to be minimized in order to avoid harm to the retina. However, the aberrations of the anterior eye elements cause a distortion of the wave front and consequently an increase in size of the irradiated area and a decrease in photon density in the focal volume. Therefore, higher pulse energy is required to still surpass the threshold irradiance. In this work, aberrations in an eye model consisting of a plano-convex lens for focusing and 2-hydroxyethylmethacrylate (HEMA) in a water cuvette as eye tissue were corrected with a deformable mirror in combination with a Hartmann-Shack-sensor. The influence of an adaptive optics aberration correction on the pulse energy required for photodisruption was investigated. A reduction of the threshold energy was shown in the aberration-corrected case and the spatial confinement raised the irradiance at constant pulse energy. As less energy is required for photodisruption when correcting for wave front aberrations the potential risk of peripheral damage is reduced, especially for the retina during laser surgery in the posterior eye segment. This offers new possibilities for high precision fs-laser surgery in the treatment of several vitreal and retinal pathologies.

Short-term effects of carbon dioxide on carnation callus cell respiration. [Dianthus Caryophyllus L. ; Elodea canadensis

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

Palet, A.; Ribas-Carbo, M.; Argiles, J.M.

1991-06-01

The addition of potassium bicarbonate to the electrode cuvette immediately stimulated the rate of dark O{sub 2} uptake of photomixotrophic and heterotrophic carnation (Dianthus caryophyllus L.) callus, of Elodea canadensis (Minchx) leaves, and of other plant tissues. This phenomenon occurred at pH values lower than 7.2 to 7.8, and the stimulation depended on the concentration of gaseous CO{sub 2} in the solution. These stimulatory responses lasted several minutes and then decreased, but additional bicarbonate or gaseous CO{sub 2} again stimulated respiration, suggesting a reversible effect. Carbonic anhydrase in the solution increased the stimulatory effect of potassium bicarbonate. The CO{sub 2}/bicarbonatemore » dependent stimulation of respiration did not occur in animal tissues such as rat diaphragm and isolated hepatocytes, and was inhibited by salicylhydroxamic acid in carnation callus cells and E. canadensis leaves. This suggested that the alternative oxidase was engaged during the stimulation in plant tissues. The cytochrome pathway was severely inhibited by CO{sub 2}/bicarbonate either in the absence or in the presence of the uncoupler carbonylcyanide m-chlorophenyl hydrazone. The activity of cytochrome c oxidase of callus tissue homogenates was also inhibited by CO{sub 2}/bicarbonate. The results suggested that high carbon dioxide levels (mainly free CO{sub 2}) partially inhibited the cytochrome pathway (apparently at the oxidase level), and this block in electron transport elicited a large transient engagement of the alternative oxidase when present uninhibited.« less

Polarized Light Scanning Cryomacroscopy, Part II: Thermal Modeling and Analysis of Experimental Observations

PubMed Central

Feig, Justin S.G.; Solanki, Prem K.; Eisenberg, David P.; Rabin, Yoed

2016-01-01

This study aims at developing thermal analysis tools and explaining experimental observations made by means of polarized-light cryomacroscopy (Part I). Thermal modeling is based on finite elements analysis (FEA), where two model parameters are extracted from thermal measurements: (i) the overall heat transfer coefficient between the cuvette and the cooling chamber, and (ii) the effective thermal conductivity within the cryoprotective agent (CPA) at the upper part of the cryogenic temperature range. The effective thermal conductivity takes into account enhanced heat transfer due to convection currents within the CPA, creating the so-called Bénard cells. Comparison of experimental results with simulation data indicates that the uncertainty in simulations due to the propagation of uncertainty in measured physical properties exceeds the uncertainty in experimental measurements, which validates the modeling approach. It is shown in this study that while a cavity may form in the upper-center portion of the vitrified CPA, it has very little effect on estimating the temperature distribution within the domain. This cavity is driven by thermal contraction of the CPA, with the upper-center of the domain transitioning to glass last. Finally, it is demonstrated in this study that additional stresses may develop within the glass transition temperature range due to nonlinear behavior of the thermal expansion coefficient. This effect is reported here for the first time in the context of cryobiology, using the capabilities of polarized-light cryomacroscopy. PMID:27343139

Characterization of Truncated Tumor-Associated NADH Oxidase (ttNOX)

NASA Technical Reports Server (NTRS)

Karr, Laurel J.; Malone, Christine C.; Burk, Melissa; Moore, Blake P.; Achari, Aniruddha; Curreri, Peter A. (Technical Monitor)

2002-01-01

Bacterial, plant and animal cells possess novel surface proteins that exhibit both NADH oxidation (NOX) or hydroquinone and protein disulfide-thiol interchange. These enzymatic activities alternate to yield oscillating patterns wjth period lengths of approximately 24 minutes. The catalytic period of NOX proteins are temperature compensated and gravity responsive. We report the cloning, expression and characterization of truncated tumor-associated NADH oxidase (ttNOX), in which the membrane spanning region has been deleted. The cDNA (originated from HeLa cells) was cloned into pET-34b and pET-14b (Novagen) vectors for E. coli expression. Optimized expression and purification protocols yielded greater than 300mg per liter of culture with greater than 95% purity. Circular dichroism data was collected from a 2.7mg/ml solution in a 0.1mm cuvette with variable scanning using an Olis RSM CD spectrophotometer. The ellipticity values were scanned from 190 to 260nm. The spectra recorded have characteristics for alpha proteins with band maxima at 216nm and a possible shoulder at 212nm at 12OC and 250 C. Protein crystal screens are in progress and, to date, only small crystals have been observed. The regular periodic oscillatory change in the ttNOX protein is indicative of a possible time-keeping functional role. A single protein possessing alternating catalytic activities, with a potential biological clock function, is unprecedented and structural determination is paramount to understanding this role.

Satellite-based estimates of surface water dynamics in the Congo River Basin

NASA Astrophysics Data System (ADS)

Becker, M.; Papa, F.; Frappart, F.; Alsdorf, D.; Calmant, S.; da Silva, J. Santos; Prigent, C.; Seyler, F.

2018-04-01

In the Congo River Basin (CRB), due to the lack of contemporary in situ observations, there is a limited understanding of the large-scale variability of its present-day hydrologic components and their link with climate. In this context, remote sensing observations provide a unique opportunity to better characterize those dynamics. Analyzing the Global Inundation Extent Multi-Satellite (GIEMS) time series, we first show that surface water extent (SWE) exhibits marked seasonal patterns, well distributed along the major rivers and their tributaries, and with two annual maxima located: i) in the lakes region of the Lwalaba sub-basin and ii) in the "Cuvette Centrale", including Tumba and Mai-Ndombe Lakes. At an interannual time scale, we show that SWE variability is influenced by ENSO and the Indian Ocean dipole events. We then estimate water level maps and surface water storage (SWS) in floodplains, lakes, rivers and wetlands of the CRB, over the period 2003-2007, using a multi-satellite approach, which combines the GIEMS dataset with the water level measurements derived from the ENVISAT altimeter heights. The mean annual variation in SWS in the CRB is 81 ± 24 km3 and contributes to 19 ± 5% of the annual variations of GRACE-derived terrestrial water storage (33 ± 7% in the Middle Congo). It represents also ∼6 ± 2% of the annual water volume that flows from the Congo River into the Atlantic Ocean.

Polarized light scanning cryomacroscopy, part II: Thermal modeling and analysis of experimental observations.

PubMed

Feig, Justin S G; Solanki, Prem K; Eisenberg, David P; Rabin, Yoed

2016-10-01

This study aims at developing thermal analysis tools and explaining experimental observations made by means of polarized-light cryomacroscopy (Part I). Thermal modeling is based on finite elements analysis (FEA), where two model parameters are extracted from thermal measurements: (i) the overall heat transfer coefficient between the cuvette and the cooling chamber, and (ii) the effective thermal conductivity within the cryoprotective agent (CPA) at the upper part of the cryogenic temperature range. The effective thermal conductivity takes into account enhanced heat transfer due to convection currents within the CPA, creating the so-called Bénard cells. Comparison of experimental results with simulation data indicates that the uncertainty in simulations due to the propagation of uncertainty in measured physical properties exceeds the uncertainty in experimental measurements, which validates the modeling approach. It is shown in this study that while a cavity may form in the upper-center portion of the vitrified CPA, it has very little effect on estimating the temperature distribution within the domain. This cavity is driven by thermal contraction of the CPA, with the upper-center of the domain transitioning to glass last. Finally, it is demonstrated in this study that additional stresses may develop within the glass transition temperature range due to nonlinear behavior of the thermal expansion coefficient. This effect is reported here for the first time in the context of cryobiology, using the capabilities of polarized-light cryomacroscopy. Copyright © 2016. Published by Elsevier Inc.

Efficient one-cycle affinity selection of binding proteins or peptides specific for a small-molecule using a T7 phage display pool.

PubMed

Takakusagi, Yoichi; Kuramochi, Kouji; Takagi, Manami; Kusayanagi, Tomoe; Manita, Daisuke; Ozawa, Hiroko; Iwakiri, Kanako; Takakusagi, Kaori; Miyano, Yuka; Nakazaki, Atsuo; Kobayashi, Susumu; Sugawara, Fumio; Sakaguchi, Kengo

2008-11-15

Here, we report an efficient one-cycle affinity selection using a natural-protein or random-peptide T7 phage pool for identification of binding proteins or peptides specific for small-molecules. The screening procedure involved a cuvette type 27-MHz quartz-crystal microbalance (QCM) apparatus with introduction of self-assembled monolayer (SAM) for a specific small-molecule immobilization on the gold electrode surface of a sensor chip. Using this apparatus, we attempted an affinity selection of proteins or peptides against synthetic ligand for FK506-binding protein (SLF) or irinotecan (Iri, CPT-11). An affinity selection using SLF-SAM and a natural-protein T7 phage pool successfully detected FK506-binding protein 12 (FKBP12)-displaying T7 phage after an interaction time of only 10 min. Extensive exploration of time-consuming wash and/or elution conditions together with several rounds of selection was not required. Furthermore, in the selection using a 15-mer random-peptide T7 phage pool and subsequent analysis utilizing receptor ligand contact (RELIC) software, a subset of SLF-selected peptides clearly pinpointed several amino-acid residues within the binding site of FKBP12. Likewise, a subset of Iri-selected peptides pinpointed part of the positive amino-acid region of residues from the Iri-binding site of the well-known direct targets, acetylcholinesterase (AChE) and carboxylesterase (CE). Our findings demonstrate the effectiveness of this method and general applicability for a wide range of small-molecules.

Spectrophotometric method for quantitative measuring essential oil in aromatic water and distillate with rose smell

NASA Astrophysics Data System (ADS)

Semenova, E.; Presnyakova, V.; Goncharov, D.; Goncharov, M.; Presnyakova, E.; Presnyakov, S.; Moiseeva, I.; Kolesnikova, S.

2017-01-01

In this connection, we improved the express methods of determining the mixture of volatile aromatic substances by the spectrophotometry of aromatic water and steam distillate of essential oil raw materials (traditional or biotechnological with rose smell). Direct spectrophotometry of distillation water is impossible because it is a colloid of liquid oil and law is not observed. Therefore, it is necessary to dissolve 1 ml of distillate in ethanol in the ratio 1:4, in this case we take real solution with no lipophilic fall-out on the walls of cuvette, also the light absorption law is observed. There are stable maximums in spectrums of studied oils. Optical density of these maximums is a result of summary absorption of terpenoid components (aromatic and monoterpene alcohols, its ethers). Optical density of tested and standard solutions is measured in appropriate wavelengths. Spectrophotometric method of determination of essential oil quantity in aromatic water with rose smell differs with high sensitivity (10-5-10-6 gmol/l) and allows to determine oil concentration from 0,900 to 0,008 mg with an error less than 1%. At that, 1 ml is enough for analysis. It’s expedient to apply this method while operating with small quantity of water distillate in biochemical and biotechnological researches and also as express control for extraction and hydrodistillation of essential oil raw material (rose petals and flowers from different origin, eremothecium cultural liquid etc.).

Observations of Hydrogen and Oxygen Isotopes in Leaf Water Confirm the Craig-Gordon Model under Wide-Ranging Environmental Conditions1

PubMed Central

Roden, John S.; Ehleringer, James R.

1999-01-01

The Craig-Gordon evaporative enrichment model of the hydrogen (δD) and oxygen (δ18O) isotopes of water was tested in a controlled-environment gas exchange cuvette over a wide range (400‰ δD and 40‰ δ18O) of leaf waters. (Throughout this paper we use the term “leaf water” to describe the site of evaporation, which should not be confused with “bulk leaf water” a term used exclusively for uncorrected measurements obtained from whole leaf water extractions.) Regardless of how the isotopic composition of leaf water was achieved (i.e. by changes in source water, atmospheric vapor δD or δ18O, vapor pressure gradients, or combinations of all three), a modified version of the Craig-Gordon model was shown to be sound in its ability to predict the δD and δ18O values of water at the site of evaporation. The isotopic composition of atmospheric vapor was shown to have profound effects on the δD and δ18O of leaf water and its influence was dependent on vapor pressure gradients. These results have implications for conditions in which the isotopic composition of atmospheric vapor is not in equilibrium with source water, such as experimental systems that grow plants under isotopically enriched water regimes. The assumptions of steady state were also tested and found not to be a major limitation for the utilization of the leaf water model under relatively stable environmental conditions. After a major perturbation in the δD and δ18O of atmospheric vapor, the leaf reached steady state in approximately 2 h, depending on vapor pressure gradients. Following a step change in source water, the leaf achieved steady state in 24 h, with the vast majority of changes occurring in the first 3 h. Therefore, the Craig-Gordon model is a useful tool for understanding the environmental factors that influence the hydrogen and oxygen isotopic composition of leaf water as well as the organic matter derived from leaf water. PMID:10444100

Development of a statistical model for cervical cancer cell death with irreversible electroporation in vitro.

PubMed

Yang, Yongji; Moser, Michael A J; Zhang, Edwin; Zhang, Wenjun; Zhang, Bing

2018-01-01

The aim of this study was to develop a statistical model for cell death by irreversible electroporation (IRE) and to show that the statistic model is more accurate than the electric field threshold model in the literature using cervical cancer cells in vitro. HeLa cell line was cultured and treated with different IRE protocols in order to obtain data for modeling the statistical relationship between the cell death and pulse-setting parameters. In total, 340 in vitro experiments were performed with a commercial IRE pulse system, including a pulse generator and an electric cuvette. Trypan blue staining technique was used to evaluate cell death after 4 hours of incubation following IRE treatment. Peleg-Fermi model was used in the study to build the statistical relationship using the cell viability data obtained from the in vitro experiments. A finite element model of IRE for the electric field distribution was also built. Comparison of ablation zones between the statistical model and electric threshold model (drawn from the finite element model) was used to show the accuracy of the proposed statistical model in the description of the ablation zone and its applicability in different pulse-setting parameters. The statistical models describing the relationships between HeLa cell death and pulse length and the number of pulses, respectively, were built. The values of the curve fitting parameters were obtained using the Peleg-Fermi model for the treatment of cervical cancer with IRE. The difference in the ablation zone between the statistical model and the electric threshold model was also illustrated to show the accuracy of the proposed statistical model in the representation of ablation zone in IRE. This study concluded that: (1) the proposed statistical model accurately described the ablation zone of IRE with cervical cancer cells, and was more accurate compared with the electric field model; (2) the proposed statistical model was able to estimate the value of electric field threshold for the computer simulation of IRE in the treatment of cervical cancer; and (3) the proposed statistical model was able to express the change in ablation zone with the change in pulse-setting parameters.

Carbonic Anhydrase Activity Associated with the Cyanobacterium Synechococcus PCC7942 1

PubMed Central

Badger, Murray R.; Price, G. Dean

1989-01-01

Intact cells and crude homogenates of high (1% CO2) and low dissolved inorganic carbon (Ci) (30-50 microliters per liter of CO2) grown Synechococcus PCC7942 have carbonic anhydrase (CA)-like activity, which enables them to catalyze the exchange of 18O from CO2 to H2O. This activity was studied using a mass spectrometer coupled to a cuvette with a membrane inlet system. Intact high and low Ci cells were found to contain CA activity, separated from the medium by a membrane which is preferentially permeable to CO2. This activity is most apparent in the light, where 18O-labeled CO2 species are being taken up by the cells but the effluxing CO2 has lost most of its label to water. In the dark, low Ci cells catalyze the depletion of the 18O enrichment of CO2 and this activity is inhibited by both ethoxyzolamide and 2-(trifluoromethoxy)carbonyl cyanide. This may occur via a common inhibition of the Ci pump and the Ci pump is proposed as a potential site for the exchange of 18O. CA activity was measurable in homogenates of both cell types but was 5- to 10-fold higher in low Ci cells. This was inhibited by ethoxyzolamide with an I50 of 50 to 100 micromolar in both low and high Ci cells. A large proportion of the internal CA activity appears to be pelletable in nature. This pelletability is increased by the presence of Mg2+ in a manner similar to that of ribulose bisphosphate carboxylase-oxygenase activity and chlorophyll (thylakoids) and may be the result of nonspecific aggregation. Separation of crude homogenates on sucrose gradients is consistent with the notion that CA and ribulose bisphosphate carboxylase-oxygenase activity may be associated with the same pelletable fraction. However, we cannot unequivocally establish that CA is located within the carboxysome. The sucrose gradients show the presence of separate soluble and pelletable CA activity. This may be due to the presence of separate forms of the enzyme or may arise from the same pelletable association which is unstable during extraction. PMID:16666546

TH-CD-BRA-02: 3D Remote Dosimetry for MRI-Guided Radiation Therapy: A Hybrid Approach

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

Rankine, L; The University of North Carolina at Chapel Hill, Chapel Hill, NC; Mein, S

2016-06-15

Purpose: To validate the dosimetric accuracy of a commercially available MR-IGRT system using a combination of 3D dosimetry measurements (with PRESAGE(R) radiochromic plastic and optical-CT readout) and an in-house developed GPU-accelerated PENELOPE Monte-Carlo dose calculation system. Methods: {sup 60}Co IMRT subject to a 0.35T lateral magnetic field has recently been commissioned in our institution following AAPM’s TG-119 recommendations. We performed PRESAGE(R) sensitivity studies in 4ml cuvettes to verify linearity, MR-compatibility, and energy-independence. Using 10cm diameter PRESAGE(R), we delivered an open calibration field to examine the percent depth dose and a symmetrical 3-field plan with three adjacent regions of varying dosemore » to determine uniformity within the dosimeter under a magnetic field. After initial testing, TG-119 plans were created in the TPS and then delivered to 14.5cm 2kg PRESAGE(R) dosimeters. Dose readout was performed via optical-CT at a second institution specializing in remote 3D dosimetry. Absolute dose was measured using an IBA CC01 ion chamber and the institution standard patient-specific QA methods were used to validate plan delivery. Calculated TG-119 plans were then compared with an independent Monte Carlo dose calculation (gPENELOPE). Results: PRESAGE(R) responds linearly (R{sup 2}=0.9996) to {sup 60}Co irradiation, in the presence of a 0.35T magnetic field, with a sensitivity of 0.0305(±0.003)cm{sup −1}Gy{sup −1}, within 1% of a 6MV non-MR linac irradiation (R{sup 2}=0.9991) with a sensitivity of 0.0302(±0.003)cm{sup −1}Gy{sup −1}. Analysis of TG-119 clinical plans using 3D-gamma (3%/3mm, 10% threshold) give passing rates of: HN 99.1%, prostate 98.0%, C-shape 90.8%, and multi-target 98.5%. The TPS agreed with gPENELOPE with a mean gamma passing rate of 98.4±1.5% (2%/2mm) with the z-score distributions following a standard normal distribution. Conclusion: We demonstrate for the first time that 3D remote dosimetry using both experimental and computational methods is a feasible and reliable approach to commissioning MR-IMRT, which is particularly useful for less specialized clinics in adopting this new treatment modality.« less

Emissions of Monoterpenes and DMS from Corn and their Influence on Nighttime Chemical Processing of Nitrogen Oxides

NASA Astrophysics Data System (ADS)

Graus, M.; De Gouw, J. A.; Brown, S. S.; Williams, E. J.; Eller, A. S.; Gilman, J. B.; Lerner, B. M.; Fall, R.; Warneke, C.

2012-12-01

In the United States large amounts of corn are grown for the use as animal feed, for the food industry and for the production of fuel ethanol. In 2012 the acreage of corn planted was 390,000 km2 covering over 4.2% of the US land surface. The BioCORN 2011 field experiment took place in summer 2011 to look at ecosystem fluxes of volatile organic compounds (VOCs) from a cornfield in Colorado during the period of rapid biomass increase and the development of flowers and ears. Eddy covariance, soil and leaf cuvette measurements using various instruments including PTR-MS, NI-PT-CIMS and GC-MS were used to determine fluxes of VOCs, CO2 and NOx. Corn plants emit significant amounts of VOCs with methanol being the largest emission and smaller emissions of other VOCs such acetone, acetaldehyde, monoterpene and dimethylsulfide (DMS). During the day VOCs mainly react with hydroxyl radicals and during the night with nitrate radicals (NO3), where emissions from corn may act as a sink for reactive nitrogen. DMS, mainly emitted from oceans and to a lesser extent from terrestrial vegetation, had a diurnal cycle: mixing ratios high during the night, but fluxes high during the day. DMS was found to dominate the reactivity of NO3 followed by monoterpenes and the heterogeneous loss of N2O5, which has implications for the nighttime chemistry. Other results of BioCORN 2011 on VOC emissions from corn and their impact on atmospheric chemistry will be presented and discussed.

The practical application of reflectance spectrophotometry for the demonstration of haemoglobin and its degradation in bruises

PubMed Central

Hughes, V K; Ellis, P S; Burt, T; Langlois, N E I

2004-01-01

Aims: To develop a non-invasive method to demonstrate the presence of haemoglobin and its degradation products in bruises in live human subjects for the purposes of objectively assisting in the determination of the age of a bruise. Methods: The cuvette holder unit of a Cary 100 Bio UV-Visible Spectrophotometer was replaced with the manufacture’s fibre optic cable and optical reflectance probe. The probe was placed on the skin surface. The absorption spectrum from 780 to 380 nm was collected and transformed into the first derivative. Calculation of the first derivative permits absorption attributed to haemoglobin degradation (primarily to bilirubin, but also haemosiderin) to be separated from absorption by haemoglobin. First derivative and colorimetry values, expressed as CIEL*a*b data, were derived from scans of 50 bruises. Results: The fibre optic cable and probe allowed the spectrophotometer to collect reproducible absorption spectra of bruises in the skin of living subjects. A bruise at three days has greater negative first derivative values at 480 and 490 nm than does a fresh bruise, indicating the local degradation of haemoglobin. Correlation between the first derivative and the CIEL*a*b “b” values in a series of bruises indicates that the yellow colour in a bruise is proportional to the amount of local haemoglobin breakdown. Conclusion: The ability to demonstrate the presence of haemoglobin and measure its degradation in bruises in living human subjects by a non-invasive method has not been described previously, and may be of use in the objective ageing of bruises for forensic purposes. PMID:15047735

Green fiber lasers: An alternative to traditional DPSS green lasers for flow cytometry

PubMed Central

Telford, William G.; Babin, Sergey A.; Khorev, Serge V.; Rowe, Stephen H.

2009-01-01

Green and yellow diode-pumped solid state (DPSS) lasers (532 and 561 nm) have become common fixtures on flow cytometers, due to their efficient excitation of phycoerythrin (PE) and its tandems, and their ability to excite an expanding array of expressible red fluorescent proteins. Nevertheless, they have some disadvantages. DPSS 532 nm lasers emit very close to the fluorescein bandwidth, necessitating optical modifications to permit detection of fluorescein and GFP. DPSS 561 nm lasers likewise emit very close to the PE detection bandwidth, and also cause unwanted excitation of APC and its tandems, requiring high levels of crossbeam compensation to reduce spectral overlap into the PE tandems. In this paper, we report the development of a new generation of green fiber lasers that can be engineered to emit in the range between 532 and 561 nm. A 550 nm green fiber laser was integrated into both a BD LSR II™ cuvette and FACSVantage DiVa™ jet-in-air cell sorter. This laser wavelength avoided both the fluorescein and PE bandwidths, and provided better excitation of PE and the red fluorescent proteins DsRed and dTomato than a power-matched 532 nm source. Excitation at 550 nm also caused less incidental excitation of APC and its tandems, reducing the need for crossbeam compensation. Excitation in the 550 nm range therefore proved to be a good compromise between 532 and 561 nm sources. Fiber laser technology is therefore providing the flexibility necessary for precisely matching laser wavelengths to our flow cytometry applications. PMID:19777600

William E. Vidaver (1921-2017): an innovator, enthusiastic scientist, inspiring teacher and a wonderful friend.

PubMed

Burr, A H Jay; Vidaver, Aaron; Schreiber, Ulrich; Bruce, Doug; Donnelly, Danielle J

2018-06-01

William (Bill) E. Vidaver (February 2, 1921-August 31, 2017), who did his Ph.D. with Laurence (Larry) R. Blinks at Stanford (1964) and a postdoc with C. Stacy French (1965), taught and did research at Simon Fraser University (SFU) for almost 30 years. Here he published over 80 papers in photosynthesis-related areas co-authored by his graduate students, postdocs, visiting professors and SFU colleagues. He developed a unique high-pressure cuvette for the study of oxygen exchange and studied high-pressure effects in photosynthesis. Ulrich (Uli) Schreiber, as a postdoctoral fellow from Germany, introduced measurements on chlorophyll (Chl) a fluorescence to Bill's lab, leading to the discovery of reversible inhibition of excitation energy transfer between photosynthetic pigments and of a pivotal role of O 2 in the oxidation of the electron transport chain between Photosystem II (PS II) and PS I. Bill's and Uli's work led to a patent of a portable chlorophyll fluorometer, the first available commercially, which was later modified to measure whole plantlets. The latter was used in pioneering measurement of the health of forest and crop plants undergoing in vitro clonal micropropagation. With several other researchers (including Doug Bruce, the late Radovan Popovic, and Sarah Swenson), he localized the quenching site of O 2 and showed a dampening effect on measurements of the four-step process of O 2 production by endogenous oxygen uptake. Bill is remembered as a hard-working but fun-loving person with a keen mind and strong sense of social justice.

Novel microscale approaches for easy, rapid determination of protein stability in academic and commercial settings

PubMed Central

Alexander, Crispin G.; Wanner, Randy; Johnson, Christopher M.; Breitsprecher, Dennis; Winter, Gerhard; Duhr, Stefan; Baaske, Philipp; Ferguson, Neil

2014-01-01

Chemical denaturant titrations can be used to accurately determine protein stability. However, data acquisition is typically labour intensive, has low throughput and is difficult to automate. These factors, combined with high protein consumption, have limited the adoption of chemical denaturant titrations in commercial settings. Thermal denaturation assays can be automated, sometimes with very high throughput. However, thermal denaturation assays are incompatible with proteins that aggregate at high temperatures and large extrapolation of stability parameters to physiological temperatures can introduce significant uncertainties. We used capillary-based instruments to measure chemical denaturant titrations by intrinsic fluorescence and microscale thermophoresis. This allowed higher throughput, consumed several hundred-fold less protein than conventional, cuvette-based methods yet maintained the high quality of the conventional approaches. We also established efficient strategies for automated, direct determination of protein stability at a range of temperatures via chemical denaturation, which has utility for characterising stability for proteins that are difficult to purify in high yield. This approach may also have merit for proteins that irreversibly denature or aggregate in classical thermal denaturation assays. We also developed procedures for affinity ranking of protein–ligand interactions from ligand-induced changes in chemical denaturation data, and proved the principle for this by correctly ranking the affinity of previously unreported peptide–PDZ domain interactions. The increased throughput, automation and low protein consumption of protein stability determinations afforded by using capillary-based methods to measure denaturant titrations, can help to revolutionise protein research. We believe that the strategies reported are likely to find wide applications in academia, biotherapeutic formulation and drug discovery programmes. PMID:25262836

Alveolar epithelial cell processing of nanoparticles activates autophagy and lysosomal exocytosis.

PubMed

Sipos, Arnold; Kim, Kwang-Jin; Chow, Robert H; Flodby, Per; Borok, Zea; Crandall, Edward D

2018-05-03

Utilizing confocal microscopy, we quantitatively assessed uptake, processing and egress of near infrared (NIR)-labeled carboxylated polystyrene nanoparticles (PNP) in live alveolar epithelial cells (AEC) during interactions with primary rat AEC monolayers (RAECM). PNP fluorescence intensity (content) and colocalization with intracellular vesicles in a cell were determined over the entire cell volume via z-stacking. Isotropic cuvette-based microfluorimetry was used to determine PNP concentration ([PNP]) from anisotropic measurements of PNP content assessed by confocal microscopy. Results showed that PNP uptake kinetics and steady state intracellular content decreased as diameter increased from 20 to 200 nm. For 20 nm PNP, uptake rate and steady state intracellular content increased with increased apical [PNP], but were unaffected by inhibition of endocytic pathways. Intracellular PNP increasingly co-localized with autophagosomes and/or lysosomes over time. PNP egress exhibited fast [Ca2+]-dependent release and a slower diffusion-like process. Inhibition of microtubule polymerization curtailed rapid PNP egress, resulting in elevated vesicular and intracellular PNP content. Interference with autophagosome formation led to slower PNP uptake and markedly decreased steady state intracellular content. At steady state, cytosolic [PNP] was higher than apical [PNP] and vesicular [PNP] (~80% of intracellular PNP content) exceeded both cytosolic [PNP] and intracellular [PNP]. These data are consistent with the hypotheses that (1) autophagic processing of nanoparticles is essential for maintenance of AEC integrity, (2) altered autophagy and/or lysosomal exocytosis may lead to AEC injury and (3) intracellular [PNP] in AEC is regulable, suggesting strategies for enhancement of nanoparticle-driven AEC gene/drug delivery and/or amelioration of AEC nanoparticle-related cellular toxicity.

Measurement and quantification of fluorescent changes in ocular tissue using a novel confocal instrument

NASA Astrophysics Data System (ADS)

Buttenschoen, Kim K.; Girkin, John M.; Daly, Daniel J.

2014-05-01

Our sight is a major contributor to our quality of life. The treatment of diseases like macular degeneration and glaucoma, however, presents a challenge as the delivery of medication to ocular tissue is not well understood. The instrument described here will help quantify targeted delivery by non-invasively and simultaneously measuring light reflected from and fluorescence excited in the eye, used as position marker and to track compounds respectively. The measurement concept has been proven by monitoring the diffusion of fluorescein and a pharmaceutical compound for treating open angle glaucoma in vitro in a cuvette and in ex vivo porcine eyes. To obtain a baseline of natural fluorescence we measured the change in corneal and crystalline lens autofluorescence in volunteers over a week. We furthermore present data on 3D ocular autofluorescence. Our results demonstrate the capability to measure the location and concentration of the compound of interest with high axial and temporal resolution of 178 μm and 0.6 s respectively. The current detection limit is 2 nM for fluorescein, and compounds with a quantum yield as low as 0.01 were measured to concentrations below 1 μM. The instrument has many applications in assessing the diffusion of fluorescent compounds through the eye and skin in vitro and in vivo, measuring autofluorescence of ocular tissues and reducing the number of animals needed for research. The instrument has the capability of being used both in the clinical and home care environment opening up the possibility of measuring controlled drug release in a patient friendly manner.

40 CFR 91.327 - Sampling system requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Sampling system requirements. 91.327....327 Sampling system requirements. (a) Sample component surface temperature. For sampling systems which..., sample line section, filters, and so forth) in the heated portion of the sampling system that has a...

40 CFR 91.327 - Sampling system requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Sampling system requirements. 91.327....327 Sampling system requirements. (a) Sample component surface temperature. For sampling systems which..., sample line section, filters, and so forth) in the heated portion of the sampling system that has a...

40 CFR 63.166 - Standards: Sampling connection systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Standards: Sampling connection systems...: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed-purge... defined in 40 CFR part 261. (c) In-situ sampling systems and sampling systems without purges are exempt...

40 CFR 63.166 - Standards: Sampling connection systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Sampling connection systems...: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed-purge... defined in 40 CFR part 261. (c) In-situ sampling systems and sampling systems without purges are exempt...

40 CFR 60.482-5 - Standards: Sampling connection systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Sampling connection systems... Standards: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed... sampling systems and sampling systems without purges are exempt from the requirements of paragraphs (a) and...

40 CFR 60.482-5 - Standards: Sampling connection systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards: Sampling connection systems... Standards: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed... sampling systems and sampling systems without purges are exempt from the requirements of paragraphs (a) and...

40 CFR 86.1509 - Exhaust gas sampling system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Exhaust gas sampling system. 86.1509... Procedures § 86.1509 Exhaust gas sampling system. (a) The exhaust gas sampling system shall transport the... sample (i.e., water removed) to the analysis system. (c) A CVS sampling system with bag or continuous...

Microgravity Testing of a Surface Sampling System for Sample Return from Small Solar System Bodies

NASA Technical Reports Server (NTRS)

Franzen, M. A.; Preble, J.; Schoenoff, M.; Halona, K.; Long, T. E.; Park, T.; Sears, D. W. G.

2004-01-01

The return of samples from solar system bodies is becoming an essential element of solar system exploration. The recent National Research Council Solar System Exploration Decadal Survey identified six sample return missions as high priority missions: South-Aitken Basin Sample Return, Comet Surface Sample Return, Comet Surface Sample Return-sample from selected surface sites, Asteroid Lander/Rover/Sample Return, Comet Nucleus Sample Return-cold samples from depth, and Mars Sample Return [1] and the NASA Roadmap also includes sample return missions [2] . Sample collection methods that have been flown on robotic spacecraft to date return subgram quantities, but many scientific issues (like bulk composition, particle size distributions, petrology, chronology) require tens to hundreds of grams of sample. Many complex sample collection devices have been proposed, however, small robotic missions require simplicity. We present here the results of experiments done with a simple but innovative collection system for sample return from small solar system bodies.

Microfluidic-Based Robotic Sampling System for Radioactive Solutions

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

Jack D. Law; Julia L. Tripp; Tara E. Smith

A novel microfluidic based robotic sampling system has been developed for sampling and analysis of liquid solutions in nuclear processes. This system couples the use of a microfluidic sample chip with a robotic system designed to allow remote, automated sampling of process solutions in-cell and facilitates direct coupling of the microfluidic sample chip with analytical instrumentation. This system provides the capability for near real time analysis, reduces analytical waste, and minimizes the potential for personnel exposure associated with traditional sampling methods. A prototype sampling system was designed, built and tested. System testing demonstrated operability of the microfluidic based sample systemmore » and identified system modifications to optimize performance.« less

40 CFR 65.113 - Standards: Sampling connection systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... (d) In-situ sampling systems. In-situ sampling systems and sampling systems without purges are exempt... implementation date specified in § 65.1(f). (b) Equipment requirement. Each sampling connection system shall be equipped with a closed-purge, closed-loop, or closed vent system except as provided in paragraph (d) of...

40 CFR 65.113 - Standards: Sampling connection systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... (d) In-situ sampling systems. In-situ sampling systems and sampling systems without purges are exempt... implementation date specified in § 65.1(f). (b) Equipment requirement. Each sampling connection system shall be equipped with a closed-purge, closed-loop, or closed vent system except as provided in paragraph (d) of...

Calcium signals recorded from cut frog twitch fibers containing antipyrylazo III

PubMed Central

1987-01-01

The Ca indicator antipyrylazo III was introduced into cut frog twitch fibers by diffusion (Maylie, J., M. Irving, N. L. Sizto, and W. K. Chandler. 1987. Journal of General Physiology. 89:41-81). Like arsenazo III, antipyrylazo III was largely bound to or sequestered by intracellular constituents; on average, a fraction 0.68 was so immobilized. After action potential stimulation, there was an early change in absorbance, with a wavelength dependence that nearly matched a cuvette Ca-difference spectrum. As with arsenazo III, this signal became prolonged as experiments progressed. In a freshly prepared cut fiber containing 0.3 mM indicator, the absorbance change had an average half-width of 10 ms at 18 degrees C. The peak amplitude of this Ca signal depended on the indicator concentration in a roughly parabolic manner, which is consistent with a 1:2 stoichiometry for Ca:indicator complexation and, for indicator concentrations less than or equal to 0.4 mM, constant peak free [Ca]. If all the antipyrylazo III inside a fiber can react normally with Ca, peak free [Ca] is 3 microM at 18 degrees C. If only freely diffusible indicator can react, the estimate is 42 microM. The true amplitude probably lies somewhere in between. The time course of Ca binding to intracellular buffers and of Ca release from the sarcoplasmic reticulum is estimated from the 3- and 42- microM myoplasmic [Ca] transients. After action potential stimulation, the release waveform is rapid and brief; its latency after the surface action potential is 2-3 ms and its half-width is 2-4 ms. This requires rapid coupling between the action potential in the transverse tubular system and Ca release from the sarcoplasmic reticulum. The peak fractional occupancy calculated for Ca-regulatory sites on troponin is 0.46 for the 3-microM transient and 0.93 for the 42-microM transient. During a 100-ms tetanus at 100 Hz, the corresponding fractional occupancies are 0.56 and 0.94. The low value of occupancy associated with the low-amplitude [Ca] calibration seems inconsistent with a brief tetanus being able to produce near-maximal activation (Blinks, J. R., R. Rudel, and S. R. Taylor. 1978. Journal of Physiology. 277:291-323; Lopez J. R., L. A. Wanck, and S. R. Taylor. 1981. Science. 214:47-82). PMID:3494102

Carbon dioxide exchange in Norway spruce at the shoot, tree and ecosystem scale.

PubMed

Wallin, G; Linder, S; Lindroth, A; Räntfors, M; Flemberg, S; Grelle, A

2001-08-01

Net CO2 exchange in a 35-year-old boreal Norway spruce (Picea abies (L.) Karst.) forest in northern Sweden was measured at the shoot (NSE), tree (NTE) and ecosystem levels (NEE) by means of shoot cuvettes, whole-tree chambers and the eddy covariance technique, respectively. We compared the dynamics of gross primary production (GPP) at the three levels during the course of a single week. The diurnal dynamics of GPP at each level were estimated by subtracting half-hourly or hourly model-estimated values of total respiration (excluding light-dependent respiration) from net CO(2) exchange. The relationship between temperature and total respiration at each level was derived from nighttime measurements of NSE, NTE and NEE over the course of 1 month. There was a strong linear relationship (r2 = 0.93) between the hourly estimates of GPP at the shoot and tree levels, but the correlation between shoot- and ecosystem-level GPP was weaker (r2 = 0.69). However, the correlation between shoot- and ecosystem-level GPP was improved (r2 = 0.88) if eddy covariance measurements were restricted to periods when friction velocity was > or = 0.5 m s(-1). Daily means were less dependent on friction velocity, giving an r2 value of 0.94 between shoot- and ecosystem-level GPP. The correlation between shoot and tree levels also increased when daily means were compared (r2 = 0.98). Most of the measured variation in carbon exchange rate among the shoot, tree and ecosystem levels was the result of periodic low coupling between vegetation and the atmosphere at the ecosystem level. The results validate the use of measurements at the shoot and tree level for analyzing the contribution of different compartments to net ecosystem CO2 exchange.

Gravitaxis in the flagellate Euglena gracilis--results from NiZeMi, clinostat and sounding rocket flights.

PubMed

Häder, D P

1994-05-01

Many motile microorganisms including flagellates such as the green Euglena gracilis move up and down within the water column and use a number of external clues for their orientation, the most important of which may be light and gravity. The cells use positive phototaxis and negative gravitaxis to move closer to the surface of the water column which for energetic reasons is vital for their survival. However, most phytoplankton organisms cannot tolerate the bright irradiance of unfiltered solar radiation at the surface which also bleaches the photosynthetic pigments, disables the photosynthetic apparatus and impairs phototaxis, gravitaxis and motility in Euglena. Thus, it is not surprising that at higher irradiances negative phototaxis operates antagonistically to the responses described above to guide the cells into deeper water where they are protected from excessive radiation. Phototaxis and gravitaxis are not independent from one another: in a vertically positioned cuvette negative gravitaxis can be "titrated" by light impinging from above and is compensated at about 30 W m-2. While the photoreceptor for phototaxis has been identified in Euglena gracilis biochemically and spectroscopically, the gravireceptor is not yet known. Young cultures of Euglena gracilis show a positive gravitaxis, the ecological signficance of which is not yet understood while older cultures show negative gravitaxis. One hypothesis concerning the nature of graviperception is based on a passive physical process such as an asymmetric distribution of the mass within the cell. However, the observation that short term UV irradiation decreases the precision of negative gravitaxis rather indicates the involvement of an active physiological gravireceptor. Furthermore, some heavy metal ions have been found to change the direction of movement from positive to negative gravitaxis in young cells.

Hyperspectral imaging with near-infrared-enabled mobile phones for tissue oximetry

NASA Astrophysics Data System (ADS)

Lin, Jonathan L.; Ghassemi, Pejhman; Chen, Yu; Pfefer, Joshua

2018-02-01

Hyperspectral reflectance imaging (HRI) is an emerging clinical tool for characterizing spatial and temporal variations in blood perfusion and oxygenation for applications such as burn assessment, wound healing, retinal exams and intraoperative tissue viability assessment. Since clinical HRI-based oximeters often use near-infrared (NIR) light, NIR-enabled mobile phones may provide a useful platform for future point-of-care devices. Furthermore, quantitative NIR imaging on mobile phones may dramatically increase the availability and accessibility of medical diagnostics for low-resource settings. We have evaluated the potential for phone-based NIR oximetry imaging and elucidated factors affecting performance using devices from two different manufacturers, as well as a scientific CCD. A broadband light source and liquid crystal tunable filter were used for imaging at 10 nm bands from 650 to 1000 nm. Spectral sensitivity measurements indicated that mobile phones with standard NIR blocking filters had minimal response beyond 700 nm, whereas one modified phone showed sensitivity to 800 nm and another to 1000 nm. Red pixel channels showed the greatest sensitivity up to 800 nm, whereas all channels provided essentially equivalent sensitivity at longer wavelengths. Referencing of blood oxygenation levels was performed with a CO-oximeter. HRI measurements were performed using cuvettes filled with hemoglobin solutions of different oxygen saturation levels. Good agreement between absorbance spectra measured with mobile phone and a CCD cameras were seen for wavelengths below 900 nm. Saturation estimates showed root-mean-squared-errors of 5.2% and 4.5% for the CCD and phone, respectively. Overall, this work provides strong evidence of the potential for mobile phones to provide quantitative spectral imaging in the NIR for applications such as oximetry, and generates practical insights into factors that impact performance as well as test methods for performance assessment.

Electroporation of mRNA as Universal Technology Platform to Transfect a Variety of Primary Cells with Antigens and Functional Proteins.

PubMed

Gerer, Kerstin F; Hoyer, Stefanie; Dörrie, Jan; Schaft, Niels

2017-01-01

Electroporation (EP) of mRNA into human cells is a broadly applicable method to transiently express proteins of choice in a variety of different cell types. We have spent more than a decade to optimize and adapt this method, first for antigen-loading of dendritic cells (DCs), and subsequently for T cells, B cells, bulk PBMCs, and several cell lines. In this regard, antigens were introduced, processed, and presented in context of MHC class I and II. Next to that, functional proteins like adhesion receptors, T-cell receptors (TCRs), chimeric antigen receptors (CARs), constitutively active signal transducers, and others were successfully expressed. We have also established this protocol under full GMP compliance as part of a manufacturing license to produce mRNA-electroporated DCs for therapeutic vaccination in clinical trials. Therefore, we here want to share our universal mRNA electroporation protocol and the experience we have gathered with this method. The advantages of the transfection method presented here are: (1) easy adaptation to different cell types, (2) scalability from 10 6 to approximately 10 8 cells per shot, (3) high transfection efficiency (80-99 %), (4) homogenous protein expression, (5) GMP compliance if the EP is performed in a class A clean room, and (6) no transgene integration into the genome. The provided protocol involves: Opti-MEM® as EP medium, a square-wave pulse with 500 V, and 4 mm cuvettes. To adapt the protocol to differently sized cells, simply the pulse time is altered. Next to the basic protocol, we also provide an extensive list of hints and tricks, which in our opinion are of great value for everyone who intends to use this transfection technique.

Photokinetic Drug Delivery: Light-Enhanced Permeation in an In Vitro Eye Model.

PubMed

Godley, Bernard F; Kraft, Edward R; Giannos, Steven A; Zhao, Zhen-Yang; Haag, Anthony M; Wen, Julie W

2015-12-01

To investigate light-enhanced molecular movement as a potential technology for drug delivery. To do this, we developed an in vitro eye model while representing similar concentration gradient conditions and compositions found in the eye. The eye model unit was fabricated by inserting a cross-linked type I collagen membrane in a spectrophotometer cuvette with 1% hyaluronic acid as the drug recipient medium. Photokinetic delivery was studied by illuminating 1 mg/mL methotrexate (MTX) placed in the drug donor compartment on top of the membrane, with noncoherent 450 nm light at 8.2 mW from an LED source pulsed at 25 cycles per second, placed in contact with the solution. A modified UV-visual spectrophotometer was employed to rapidly determine the concentration of MTX, at progressive 1 mm distances away from the membrane, within the viscous recipient medium of the model eye after 1 h. A defined, progressive concentration gradient was observed within the nonagitated drug recipient media, diminishing with greater distances from the membrane. Transport of MTX through the membrane was significantly enhanced (ranging from 2 to 3 times, P < 0.05 to P ≤ 0.001) by photokinetic methods compared with control conditions by determining drug concentrations at 4 defined distances from the membrane. According to scanning electron microscopy images, no structural damage or shunts were created on the surface of the cross-linked gelatin membrane. The application of pulsed noncoherent visible light significantly enhances the permeation of MTX through a cross-linked collagen membrane and hyaluronic acid recipient medium without causing structural damage to the membrane.

40 CFR 90.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2013 CFR

2013-07-01

... sampling probe. (2) Exhaust flow metering system. A dilute exhaust flow metering system must be used to... exhaust. The background probe must draw a representative sample of the background air during each sampling... (bag) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe...

40 CFR 90.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... sampling probe. (2) Exhaust flow metering system. A dilute exhaust flow metering system must be used to... exhaust. The background probe must draw a representative sample of the background air during each sampling... (bag) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe...

40 CFR 90.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... sampling probe. (2) Exhaust flow metering system. A dilute exhaust flow metering system must be used to... exhaust. The background probe must draw a representative sample of the background air during each sampling... (bag) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe...

40 CFR 90.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2012 CFR

2012-07-01

... sampling probe. (2) Exhaust flow metering system. A dilute exhaust flow metering system must be used to... exhaust. The background probe must draw a representative sample of the background air during each sampling... (bag) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe...

40 CFR 90.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... sampling probe. (2) Exhaust flow metering system. A dilute exhaust flow metering system must be used to... exhaust. The background probe must draw a representative sample of the background air during each sampling... (bag) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe...

Cost Analysis of Various Low Pathogenic Avian Influenza Surveillance Systems in the Dutch Egg Layer Sector

PubMed Central

Rutten, Niels; Gonzales, José L.; Elbers, Armin R. W.; Velthuis, Annet G. J.

2012-01-01

Background As low pathogenic avian influenza viruses can mutate into high pathogenic viruses the Dutch poultry sector implemented a surveillance system for low pathogenic avian influenza (LPAI) based on blood samples. It has been suggested that egg yolk samples could be sampled instead of blood samples to survey egg layer farms. To support future decision making about AI surveillance economic criteria are important. Therefore a cost analysis is performed on systems that use either blood or eggs as sampled material. Methodology/Principal Findings The effectiveness of surveillance using egg or blood samples was evaluated using scenario tree models. Then an economic model was developed that calculates the total costs for eight surveillance systems that have equal effectiveness. The model considers costs for sampling, sample preparation, sample transport, testing, communication of test results and for the confirmation test on false positive results. The surveillance systems varied in sampled material (eggs or blood), sampling location (farm or packing station) and location of sample preparation (laboratory or packing station). It is shown that a hypothetical system in which eggs are sampled at the packing station and samples prepared in a laboratory had the lowest total costs (i.e. € 273,393) a year. Compared to this a hypothetical system in which eggs are sampled at the farm and samples prepared at a laboratory, and the currently implemented system in which blood is sampled at the farm and samples prepared at a laboratory have 6% and 39% higher costs respectively. Conclusions/Significance This study shows that surveillance for avian influenza on egg yolk samples can be done at lower costs than surveillance based on blood samples. The model can be used in future comparison of surveillance systems for different pathogens and hazards. PMID:22523543

40 CFR 90.327 - Sampling system requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Sampling system requirements. 90.327... Equipment Provisions § 90.327 Sampling system requirements. (a) Sample component surface temperature. For sampling systems which use heated components, use engineering judgment to locate the coolest portion of...

40 CFR 90.327 - Sampling system requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Sampling system requirements. 90.327... Equipment Provisions § 90.327 Sampling system requirements. (a) Sample component surface temperature. For sampling systems which use heated components, use engineering judgment to locate the coolest portion of...

40 CFR 89.419 - Dilute gaseous exhaust sampling and analytical system description.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Continuous HC measurement system. (i) The continuous HC sample system (as shown in Figure 2 or 3 in appendix... this is not required. (ii) No other analyzers may draw a sample from the continuous HC sample probe... continuous HC sampling system shall consist of a probe (which must raise the sample to the specified...

Emission of Trimethylamine from Chenopodium vulvaria - first results from quantifiying plant emissions of amines

NASA Astrophysics Data System (ADS)

Sun, Shang; Neftel, Albrecht; Jörg, Sintermann; Derstroff, Bettina; Sauvage, Carina; Bohley, Katharina; Kadereit, Gudrun; Williams, Jonathan; Pöhlker, Christopher; Kesselmeier, Jürgen; Sörgel, Matthias

2016-04-01

Amines comprise a wide range of nitrogenous organic compounds such as aliphatic methylamines MA. TMA is the most common amine species emitted by various sources and the most abundant amine in the atmosphere (Ge et al., 2011a). Additionally, TMA has been found to be the dominant amine species in the gas-phase compared to MMA and DMA at agriculture sites (Schade and Crutzen, 1995). On the global scale, the knowledge about the fluxes of most amines is limited (Ge et al., 2011a). Furthermore, terrestrial vegetation is also assumed to be a potential source for amines (Schade and Crutzen, 1995). There are a few studies from the end of the 19th century until 1975, which described high amount of MA-emission from certain plant species, which was associated with their plant tissues or with blossoms during flowering (Smith, 1971). Despite the low atmospheric concentration of amines (DMA = 0.5 ppb (Okita, 1970), TMA = 0.6 -1.6 ppb (Fujii and Kitai, 1987)), previous studies have already shown that amines play an important role in the New aerosol Particle Formation (NPF) (Almeida et al., 2013, and summarized in Sintermann and Neftel, 2015). In the atmosphere, NPF occurs frequently from gas-phase precursors. High uncertainty exists in the estimation of the global secondary aerosols budget, which was cause to the uncertain contribution of the gas-phase precursors to the NPF (Spracklen et al., 2011). It becomes more clearly that instead of binary systems of sulfuric acid and water, ternary system of sulfuric acid, water and a neutralizing compound as NH3 or amines is a key system in NPF (Almeida et al., 2013, Kurten et al., 2014). Despite their low atmospheric concentrations amines may play, at least locally, a crucial role in aerosol formation. In this study, we focus on the plant species chenopodium vulvaria, which is well known as a strong TMA-emitter (Dessaignes, 1856). But TMA emission rates from that plant species was not determined systematically up to now. In this study, we investigate on the TMA emission from chenopodium vulvaria in our dynamic cuvette system described in Sun et al. (2015). As TMA plays a key role in the atmospheric NPF, the results should give a perception of the contribution of the TMA emission from the terrestrial vegetation to the global NPF. Reference Almeida et al., Nature, 502, 359-363, 2013. Ge et al., Atmospheric Environment, 45, 524-546, 2011. Dessaignes, M., C. R. Acad. Sei. (Paris), 43, 670-671, 1856. Fujii et al., Analytical Chemistry, 59, 379-382, 1987. Kurten et al., Proceedings of the National Academy of Sciences, 111, 15019-15024, 2014. Okita, T., Atmospheric Environment, 4, 93-102 1970. Schade, G.W. and Crutzen, P.J., Journal of Atmospheric Chemistry, 22, 319-346, 1995. Sintermann, J. and Neftel, A., Biogeosciences, 12(11), 3225-3240, 2015. Smith, T. A., Biological Reviews, 46, 201-241, 1971. Spracklen et al., Atmospheric Chemistry and Physics, 11, 12 109-12 136, 2011. Sun et al., Atmospheric Measurement Techniques Discuss, 8, 12051-12104, doi:10.5194/amtd-8-12051-2015, 2015

40 CFR 63.1013 - Sampling connection systems standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-purge system must be covered or closed when not being filled or emptied. (d) In-situ sampling systems. In-situ sampling systems and sampling systems without purges are exempt from the requirements of... than the compliance dates specified in the referencing subpart. (b) Equipment requirement. Each...

40 CFR 63.1013 - Sampling connection systems standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-purge system must be covered or closed when not being filled or emptied. (d) In-situ sampling systems. In-situ sampling systems and sampling systems without purges are exempt from the requirements of... than the compliance dates specified in the referencing subpart. (b) Equipment requirement. Each...

40 CFR 63.1013 - Sampling connection systems standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-purge system must be covered or closed when not being filled or emptied. (d) In-situ sampling systems. In-situ sampling systems and sampling systems without purges are exempt from the requirements of... than the compliance dates specified in the referencing subpart. (b) Equipment requirement. Each...

40 CFR 63.1032 - Sampling connection systems standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... of a closed purge system must be covered or closed when not being filled or emptied. (d) In-situ sampling systems. In-situ sampling systems and sampling systems without purges are exempt from the... no later than the compliance dates specified in the referencing subpart. (b) Equipment requirement...

40 CFR 63.1032 - Sampling connection systems standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... of a closed purge system must be covered or closed when not being filled or emptied. (d) In-situ sampling systems. In-situ sampling systems and sampling systems without purges are exempt from the... no later than the compliance dates specified in the referencing subpart. (b) Equipment requirement...

40 CFR 205.171-2 - Test exhaust system sample selection and preparation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Test exhaust system sample selection... Systems § 205.171-2 Test exhaust system sample selection and preparation. (a)(1) Exhaust systems comprising the sample which are required to be tested under a test request in accordance with this subpart...

Portable ultrahigh-vacuum sample storage system for polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy

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

Watanabe, Yoshihide, E-mail: e0827@mosk.tytlabs.co.jp; Nishimura, Yusaku F.; Suzuki, Ryo

A portable ultrahigh-vacuum sample storage system was designed and built to investigate the detailed geometric structures of mass-selected metal clusters on oxide substrates by polarization-dependent total-reflection fluorescence x-ray absorption fine structure spectroscopy (PTRF-XAFS). This ultrahigh-vacuum (UHV) sample storage system provides the handover of samples between two different sample manipulating systems. The sample storage system is adaptable for public transportation, facilitating experiments using air-sensitive samples in synchrotron radiation or other quantum beam facilities. The samples were transferred by the developed portable UHV transfer system via a public transportation at a distance over 400 km. The performance of the transfer system was demonstratedmore » by a successful PTRF-XAFS study of Pt{sub 4} clusters deposited on a TiO{sub 2}(110) surface.« less

40 CFR 91.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2013 CFR

2013-07-01

... that complete mixing of the engine exhaust and background air is assured prior to the sampling probe.... The background probe must draw a representative sample of the background air during each sampling mode...) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe, this system...

40 CFR 91.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... that complete mixing of the engine exhaust and background air is assured prior to the sampling probe.... The background probe must draw a representative sample of the background air during each sampling mode...) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe, this system...

40 CFR 91.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... that complete mixing of the engine exhaust and background air is assured prior to the sampling probe.... The background probe must draw a representative sample of the background air during each sampling mode...) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe, this system...

40 CFR 91.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... that complete mixing of the engine exhaust and background air is assured prior to the sampling probe.... The background probe must draw a representative sample of the background air during each sampling mode...) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe, this system...

40 CFR 91.420 - CVS concept of exhaust gas sampling system.

Code of Federal Regulations, 2012 CFR

2012-07-01

... that complete mixing of the engine exhaust and background air is assured prior to the sampling probe.... The background probe must draw a representative sample of the background air during each sampling mode...) sampling system. If a critical flow venturi (CFV) is used on the dilute exhaust sample probe, this system...

Stochastic Stability of Nonlinear Sampled Data Systems with a Jump Linear Controller

NASA Technical Reports Server (NTRS)

Gonzalez, Oscar R.; Herencia-Zapana, Heber; Gray, W. Steven

2004-01-01

This paper analyzes the stability of a sampled- data system consisting of a deterministic, nonlinear, time- invariant, continuous-time plant and a stochastic, discrete- time, jump linear controller. The jump linear controller mod- els, for example, computer systems and communication net- works that are subject to stochastic upsets or disruptions. This sampled-data model has been used in the analysis and design of fault-tolerant systems and computer-control systems with random communication delays without taking into account the inter-sample response. To analyze stability, appropriate topologies are introduced for the signal spaces of the sampled- data system. With these topologies, the ideal sampling and zero-order-hold operators are shown to be measurable maps. This paper shows that the known equivalence between the stability of a deterministic, linear sampled-data system and its associated discrete-time representation as well as between a nonlinear sampled-data system and a linearized representation holds even in a stochastic framework.

40 CFR 264.1055 - Standards: Sampling connection systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Standards: Sampling connection systems... FACILITIES Air Emission Standards for Equipment Leaks § 264.1055 Standards: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed-purge, closed-loop, or closed-vent...

40 CFR 265.1055 - Standards: Sampling connection systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Standards: Sampling connection systems..., STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 265.1055 Standards: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed-purge, closed-loop...

40 CFR 63.1013 - Sampling connection systems standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Sampling connection systems standards... (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 1 § 63.1013 Sampling connection... sampling connection system shall be equipped with a closed purge, closed loop, or closed vent system...

40 CFR 264.1055 - Standards: Sampling connection systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Sampling connection systems... FACILITIES Air Emission Standards for Equipment Leaks § 264.1055 Standards: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed-purge, closed-loop, or closed-vent...

40 CFR 265.1055 - Standards: Sampling connection systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Sampling connection systems..., STORAGE, AND DISPOSAL FACILITIES Air Emission Standards for Equipment Leaks § 265.1055 Standards: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed-purge, closed-loop...

Robotic sampling system for an unmanned Mars mission

NASA Technical Reports Server (NTRS)

Chun, Wendell

1989-01-01

A major robotics opportunity for NASA will be the Mars Rover/Sample Return Mission which could be launched as early as the 1990s. The exploratory portion of this mission will include two autonomous subsystems: the rover vehicle and a sample handling system. The sample handling system is the key to the process of collecting Martian soils. This system could include a core drill, a general-purpose manipulator, tools, containers, a return canister, certification hardware and a labeling system. Integrated into a functional package, the sample handling system is analogous to a complex robotic workcell. Discussed here are the different components of the system, their interfaces, forseeable problem areas and many options based on the scientific goals of the mission. The various interfaces in the sample handling process (component to component and handling system to rover) will be a major engineering effort. Two critical evaluation criteria that will be imposed on the system are flexibility and reliability. It needs to be flexible enough to adapt to different scenarios and environments and acquire the most desirable specimens for return to Earth. Scientists may decide to change the distribution and ratio of core samples to rock samples in the canister. The long distance and duration of this planetary mission places a reliability burden on the hardware. The communication time delay between Earth and Mars minimizes operator interaction (teleoperation, supervisory modes) with the sample handler. An intelligent system will be required to plan the actions, make sample choices, interpret sensor inputs, and query unknown surroundings. A combination of autonomous functions and supervised movements will be integrated into the sample handling system.

40 CFR 1065.805 - Sampling system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Sampling system. 1065.805 Section 1065... ENGINE-TESTING PROCEDURES Testing With Oxygenated Fuels § 1065.805 Sampling system. (a) Dilute engine exhaust, and use batch sampling to collect proportional flow-weighted dilute samples of the applicable...

40 CFR 1065.805 - Sampling system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Sampling system. 1065.805 Section 1065... ENGINE-TESTING PROCEDURES Testing With Oxygenated Fuels § 1065.805 Sampling system. (a) Dilute engine exhaust, and use batch sampling to collect proportional flow-weighted dilute samples of the applicable...

40 CFR 60.482-5a - Standards: Sampling connection systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards: Sampling connection systems..., Reconstruction, or Modification Commenced After November 7, 2006 § 60.482-5a Standards: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed-purge, closed-loop, or closed...

40 CFR 61.242-5 - Standards: Sampling connecting systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Standards: Sampling connecting systems... for Equipment Leaks (Fugitive Emission Sources) § 61.242-5 Standards: Sampling connecting systems. (a) Each sampling connection system shall be equipped with a closed-purge, closed-loop, or closed vent...

40 CFR 60.482-5a - Standards: Sampling connection systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Sampling connection systems..., Reconstruction, or Modification Commenced After November 7, 2006 § 60.482-5a Standards: Sampling connection systems. (a) Each sampling connection system shall be equipped with a closed-purge, closed-loop, or closed...

Multidimensional System Analysis of Electro-Optic Sensors with Sampled Deterministic Output.

DTIC Science & Technology

1987-12-18

System descriptions of scanning and staring electro - optic sensors with sampled output are developed as follows. Functions representing image...to complete the system descriptions. The results should be useful for designing electro - optic sensor systems and correcting data for instrumental...effects and other experimental conditions. Keywords include: Electro - optic system analysis, Scanning sensors, Staring sensors, Spatial sampling, and Temporal sampling.

A portable molecular-sieve-based CO2 sampling system for radiocarbon measurements

NASA Astrophysics Data System (ADS)

Palonen, V.

2015-12-01

We have developed a field-capable sampling system for the collection of CO2 samples for radiocarbon-concentration measurements. Most target systems in environmental research are limited in volume and CO2 concentration, making conventional flask sampling hard or impossible for radiocarbon studies. The present system captures the CO2 selectively to cartridges containing 13X molecular sieve material. The sampling does not introduce significant under-pressures or significant losses of moisture to the target system, making it suitable for most environmental targets. The system also incorporates a significantly larger sieve container for the removal of CO2 from chambers prior to the CO2 build-up phase and sampling. In addition, both the CO2 and H2O content of the sample gas are measured continuously. This enables in situ estimation of the amount of collected CO2 and the determination of CO2 flux to a chamber. The portable sampling system is described in detail and tests for the reliability of the method are presented.

A portable molecular-sieve-based CO2 sampling system for radiocarbon measurements.

PubMed

Palonen, V

2015-12-01

We have developed a field-capable sampling system for the collection of CO2 samples for radiocarbon-concentration measurements. Most target systems in environmental research are limited in volume and CO2 concentration, making conventional flask sampling hard or impossible for radiocarbon studies. The present system captures the CO2 selectively to cartridges containing 13X molecular sieve material. The sampling does not introduce significant under-pressures or significant losses of moisture to the target system, making it suitable for most environmental targets. The system also incorporates a significantly larger sieve container for the removal of CO2 from chambers prior to the CO2 build-up phase and sampling. In addition, both the CO2 and H2O content of the sample gas are measured continuously. This enables in situ estimation of the amount of collected CO2 and the determination of CO2 flux to a chamber. The portable sampling system is described in detail and tests for the reliability of the method are presented.

Systems and methods for self-synchronized digital sampling

NASA Technical Reports Server (NTRS)

Samson, Jr., John R. (Inventor)

2008-01-01

Systems and methods for self-synchronized data sampling are provided. In one embodiment, a system for capturing synchronous data samples is provided. The system includes an analog to digital converter adapted to capture signals from one or more sensors and convert the signals into a stream of digital data samples at a sampling frequency determined by a sampling control signal; and a synchronizer coupled to the analog to digital converter and adapted to receive a rotational frequency signal from a rotating machine, wherein the synchronizer is further adapted to generate the sampling control signal, and wherein the sampling control signal is based on the rotational frequency signal.

Elimination of ``memory`` from sample handling and inlet system of a mass spectrometer

DOEpatents

Chastgner, P.

1991-05-08

This paper describes a method for preparing the sample handling and inlet system of a mass spectrometer for analysis of a subsequent sample following analysis of a previous sample comprising the flushing of the system interior with supercritical CO{sub 2} and venting the interior. The method eliminates the effect of system ``memory`` on the subsequent analysis, especially following persistent samples such as xenon and krypton.

Planetary Sample Caching System Design Options

NASA Technical Reports Server (NTRS)

Collins, Curtis; Younse, Paulo; Backes, Paul

2009-01-01

Potential Mars Sample Return missions would aspire to collect small core and regolith samples using a rover with a sample acquisition tool and sample caching system. Samples would need to be stored in individual sealed tubes in a canister that could be transfered to a Mars ascent vehicle and returned to Earth. A sample handling, encapsulation and containerization system (SHEC) has been developed as part of an integrated system for acquiring and storing core samples for application to future potential MSR and other potential sample return missions. Requirements and design options for the SHEC system were studied and a recommended design concept developed. Two families of solutions were explored: 1)transfer of a raw sample from the tool to the SHEC subsystem and 2)transfer of a tube containing the sample to the SHEC subsystem. The recommended design utilizes sample tool bit change out as the mechanism for transferring tubes to and samples in tubes from the tool. The SHEC subsystem design, called the Bit Changeout Caching(BiCC) design, is intended for operations on a MER class rover.

40 CFR 86.509-90 - Exhaust gas sampling system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Exhaust gas sampling system. 86.509-90... 1978 and Later New Motorcycles; Test Procedures § 86.509-90 Exhaust gas sampling system. (a)(1) General. The exhaust gas sampling system is designed to measure the true mass emissions of vehicle exhaust. In...

40 CFR 86.509-90 - Exhaust gas sampling system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Exhaust gas sampling system. 86.509-90... 1978 and Later New Motorcycles; Test Procedures § 86.509-90 Exhaust gas sampling system. (a)(1) General. The exhaust gas sampling system is designed to measure the true mass emissions of vehicle exhaust. In...

40 CFR 61.242-5 - Standards: Sampling connecting systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 261. (c) In-situ sampling systems and sampling systems without purges are exempt from the requirements... system, except as provided in § 61.242-1(c). Gases displaced during filling of the sample container are... required in paragraph (a) of this section shall comply with the requirements specified in paragraphs (b)(1...

40 CFR 61.242-5 - Standards: Sampling connecting systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 261. (c) In-situ sampling systems and sampling systems without purges are exempt from the requirements... system, except as provided in § 61.242-1(c). Gases displaced during filling of the sample container are... required in paragraph (a) of this section shall comply with the requirements specified in paragraphs (b)(1...

Hemolysis associated with pneumatic tube system transport for blood samples

PubMed Central

Kara, Hasan; Bayir, Aysegul; Ak, Ahmet; Degirmenci, Selim; Akinci, Murat; Agacayak, Ahmet; Marcil, Emine; Azap, Melih

2014-01-01

Objective: The frequency of hemolysis of blood samples may be increased by transport in a pneumatic tube system. The purpose of this study was to evaluate the effect of pneumatic tube system transport on hemolysis of blood samples. Methods: Blood samples were transported from the emergency department to the hospital laboratory manually by hospital staff (49 patients) or with a pneumatic tube system (53 patients). The hemolysis index and serum chemistry studies were performed on the blood samples and compared between the different methods of transport. Results: The blood samples that were transported by the pneumatic tube system had a greater frequency of hemolysis and greater mean serum potassium and median creatinine, aspartate aminotransferase, and lactate dehydrogenase levels than samples transported manually. Conclusion: Blood samples transported from the emergency department to the hospital laboratory by a pneumatic tube system may have a greater frequency of hemolysis than samples transported manually. This may necessitate repeat phlebotomy and cause a delay in completing the laboratory analysis. PMID:24639830

Test plan for evaluating the operational performance of the prototype nested, fixed-depth fluidic sampler

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

REICH, F.R.

The PHMC will provide Low Activity Wastes (LAW) tank wastes for final treatment by a privatization contractor from two double-shell feed tanks, 241-AP-102 and 241-AP-104. Concerns about the inability of the baseline ''grab'' sampling to provide large volume samples within time constraints has led to the development of a nested, fixed-depth sampling system. This sampling system will provide large volume, representative samples without the environmental, radiation exposure, and sample volume impacts of the current base-line ''grab'' sampling method. A plan has been developed for the cold testing of this nested, fixed-depth sampling system with simulant materials. The sampling system willmore » fill the 500-ml bottles and provide inner packaging to interface with the Hanford Sites cask shipping systems (PAS-1 and/or ''safe-send''). The sampling system will provide a waste stream that will be used for on-line, real-time measurements with an at-tank analysis system. The cold tests evaluate the performance and ability to provide samples that are representative of the tanks' content within a 95 percent confidence interval, to sample while mixing pumps are operating, to provide large sample volumes (1-15 liters) within a short time interval, to sample supernatant wastes with over 25 wt% solids content, to recover from precipitation- and settling-based plugging, and the potential to operate over the 20-year expected time span of the privatization contract.« less

Stochastic Stability of Sampled Data Systems with a Jump Linear Controller

NASA Technical Reports Server (NTRS)

Gonzalez, Oscar R.; Herencia-Zapana, Heber; Gray, W. Steven

2004-01-01

In this paper an equivalence between the stochastic stability of a sampled-data system and its associated discrete-time representation is established. The sampled-data system consists of a deterministic, linear, time-invariant, continuous-time plant and a stochastic, linear, time-invariant, discrete-time, jump linear controller. The jump linear controller models computer systems and communication networks that are subject to stochastic upsets or disruptions. This sampled-data model has been used in the analysis and design of fault-tolerant systems and computer-control systems with random communication delays without taking into account the inter-sample response. This paper shows that the known equivalence between the stability of a deterministic sampled-data system and the associated discrete-time representation holds even in a stochastic framework.

75 FR 52587 - 2009 Fatality Analysis Reporting System (FARS)/National Automotive Sampling System General...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-26

... DEPARTMENT OF TRANSPORTATION National Highway Traffic Safety Administration [U.S. DOT Docket Number NHTSA-2010-0122] 2009 Fatality Analysis Reporting System (FARS)/National Automotive Sampling... Administration (NHTSA)--2009 Fatality Analysis Reporting System (FARS) & National Automotive Sampling System...

Benchtop Detection of Proteins

NASA Technical Reports Server (NTRS)

Scardelletti, Maximilian C.; Varaljay, Vanessa

2007-01-01

A process, and a benchtop-scale apparatus for implementing the process, have been developed to detect proteins associated with specific microbes in water. The process and apparatus may also be useful for detection of proteins in other, more complex liquids. There may be numerous potential applications, including monitoring lakes and streams for contamination, testing of blood and other bodily fluids in medical laboratories, and testing for microbial contamination of liquids in restaurants and industrial food-processing facilities. A sample can be prepared and analyzed by use of this process and apparatus within minutes, whereas an equivalent analysis performed by use of other processes and equipment can often take hours to days. The process begins with the conjugation of near-infrared-fluorescent dyes to antibodies that are specific to a particular protein. Initially, the research has focused on using near-infrared dyes to detect antigens or associated proteins in solution, which has proven successful vs. microbial cells, and streamlining the technique in use for surface protein detection on microbes would theoretically render similar results. However, it is noted that additional work is needed to transition protein-based techniques to microbial cell detection. Consequently, multiple such dye/antibody pairs could be prepared to enable detection of multiple selected microbial species, using a different dye for each species. When excited by near-infrared light of a suitable wavelength, each dye fluoresces at a unique longer wavelength that differs from those of the other dyes, enabling discrimination among the various species. In initial tests, the dye/antibody pairs are mixed into a solution suspected of containing the selected proteins, causing the binding of the dye/antibody pairs to such suspect proteins that may be present. The solution is then run through a microcentrifuge that includes a membrane that acts as a filter in that it retains the dye/antibody/protein complexes while allowing any remaining unbound dye/antibody pairs to flow away. The retained dye/antibody/protein complexes are transferred to a cuvette, wherein they are irradiated with light from a miniature near-infrared laser delivered via a fiber-optic cable. The resulting fluorescence from the dye(s) is measured by use of a miniature spectrometer, the output of which is digitized, then analyzed by laptop computer. The software running in the computer identifies the protein species by the wavelengths of their spectral peaks and determines the amounts of the proteins, and thus, one day, microbes of the various species from the intensities of the peaks. The abovementioned removal of the unbound dye/antibody pairs during centrifugation prevents false positive readings. The process proves successful in detecting proteins in solution and thus can now be employed for use in microbe detection.

Real-time water and wastewater quality monitoring using LED-based fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Bridgeman, John; Zakharova, Yulia

2016-04-01

In recent years there have been a number of attempts to design and introduce into water management tools that are capable of measuring organic and microbial matter in real time and in situ. This is important, as the delivery of safe water to customers, and the discharge of good quality effluent to rivers are primary concerns to water undertakers. A novel, LED-based portable fluorimeter 'Duo Fluor' has been designed and constructed at the University of Birmingham to monitor the quality of (waste)water continuously and in real time, and its performance has been assessed in a range of environments. To be of use across a range of environments, special attention must be paid to two crucially important characteristics of such instruments, i.e. their sensitivity and robustness. Thus, the objectives of this study were: 1. To compare the performance (in terms of their sensitivity and robustness) of the Duo Fluor and two other commercial fluorescence devices in laboratory conditions. 2. To assess the performance of the Duo Fluor in situ, in real time at a 450,000PE WwTW. Initially, the impact of quinine sulphate (QS), a highly fluorescent alkaloid with high quantum fluorescence yield, on peak T fluorescence in environmental waters was examined for the Duo Fluor and two commercially available, chamber-based fluorimeters, (F1) and (F2). The instruments' responses to three scenarios were assessed: 1. Deionised water (DW) spiked with QS (from 0.05 to 0.4 mg/L); 2. Environmental water (pond water, PW) spiked with QS (from 0.05 to 0.4 mg/L); 3. Different water samples from various environmental source. The results show that the facility to amend gain settings and the suitable choice of gain are crucial to obtaining reliable data on both peaks T and C in a wide range of water types. The Duo Fluor offers both of these advantages whilst commercially available instruments currently do not. The Duo Fluor was subsequently fixed at the final effluent (FE) discharge point of a WwTW and FE was pumped into the cuvette. The instruments, along with other sensors, were checked twice a week. The Duo Fluor successfully collected data continuously from 10th August 2015 to 7th September 2015 (~500 hrs). Data analysis showed that the Duo Fluor demonstrated very good correlation with the other instruments; albeit, some commercially available instruments measure only peak T or peak C, whereas Duo Fluor measures both. The results also identified rainfall events in the catchment, which manifested themselves via decreases in both peak C and peak, suggesting that a dilution of organic and microbial matter had occurred.

78 FR 45989 - Vogtle Electric Generating Station, Units 3 and 4; Southern Nuclear Operating Company; Change to...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-30

... Generating Station, Units 3 and 4; Southern Nuclear Operating Company; Change to the Primary Sampling System.... The amendment requests to modify the Primary Sampling System (PSS) design, including changes to Tier 1....13-1 ``Primary Sampling System,'' and Subsection 2.3.13, ``Primary Sampling System'' of the Updated...

78 FR 45987 - Vogtle Electric Generating Station, Units 3 and 4; Southern Nuclear Operating Company; Change to...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-30

... Generating Station, Units 3 and 4; Southern Nuclear Operating Company; Change to the Primary Sampling System.... The amendment requests to modify the Primary Sampling System (PSS) design, including changes to Tier 1....13-1 ``Primary Sampling System,'' and Subsection 2.3.13, ``Primary Sampling System'' of the Updated...

A robust variable sampling time BLDC motor control design based upon μ-synthesis.

PubMed

Hung, Chung-Wen; Yen, Jia-Yush

2013-01-01

The variable sampling rate system is encountered in many applications. When the speed information is derived from the position marks along the trajectory, one would have a speed dependent sampling rate system. The conventional fixed or multisampling rate system theory may not work in these cases because the system dynamics include the uncertainties which resulted from the variable sampling rate. This paper derived a convenient expression for the speed dependent sampling rate system. The varying sampling rate effect is then translated into multiplicative uncertainties to the system. The design then uses the popular μ-synthesis process to achieve a robust performance controller design. The implementation on a BLDC motor demonstrates the effectiveness of the design approach.

A Robust Variable Sampling Time BLDC Motor Control Design Based upon μ-Synthesis

PubMed Central

Yen, Jia-Yush

2013-01-01

The variable sampling rate system is encountered in many applications. When the speed information is derived from the position marks along the trajectory, one would have a speed dependent sampling rate system. The conventional fixed or multisampling rate system theory may not work in these cases because the system dynamics include the uncertainties which resulted from the variable sampling rate. This paper derived a convenient expression for the speed dependent sampling rate system. The varying sampling rate effect is then translated into multiplicative uncertainties to the system. The design then uses the popular μ-synthesis process to achieve a robust performance controller design. The implementation on a BLDC motor demonstrates the effectiveness of the design approach. PMID:24327804

Non-destructive sampling of a comet

NASA Astrophysics Data System (ADS)

Jessberger, H. L.; Kotthaus, M.

1991-04-01

Various conditions which must be met for the development of a nondestructive sampling and acquisition system are outlined and the development of a new robotic sampling system suited for use on a cometary surface is briefly discussed. The Rosetta mission of ESA will take samples of a comet nucleus and return both core and volatile samples to earth. Various considerations which must be taken into account for such a project are examined including the identification of design parameters for sample quality; the identification of the most probable site conditions; the development of a sample acquisition system with respect to these conditions; the production of model materials and model conditions; and the investigation of the relevant material properties. An adequate sampling system should also be designed and built, including various tools, and the system should be tested under simulated cometary conditions.

Reweighting of the primary sampling units in the National Automotive Sampling System

DOT National Transportation Integrated Search

1997-09-01

The original design of hte National Automotive Sampling System - formerly the National Accident Sampling System - called for 75 PSUs randomly selected from PSUs which were grouped into various strata across the U.S. The implementation of the PSU samp...

Use the Bar Code System to Improve Accuracy of the Patient and Sample Identification.

PubMed

Chuang, Shu-Hsia; Yeh, Huy-Pzu; Chi, Kun-Hung; Ku, Hsueh-Chen

2018-01-01

In time and correct sample collection were highly related to patient's safety. The sample error rate was 11.1%, because misbranded patient information and wrong sample containers during January to April, 2016. We developed a barcode system of "Specimens Identify System" through process of reengineering of TRM, used bar code scanners, add sample container instructions, and mobile APP. Conclusion, the bar code systems improved the patient safety and created green environment.

A portable molecular-sieve-based CO{sub 2} sampling system for radiocarbon measurements

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

Palonen, V., E-mail: vesa.palonen@helsinki.fi

We have developed a field-capable sampling system for the collection of CO{sub 2} samples for radiocarbon-concentration measurements. Most target systems in environmental research are limited in volume and CO{sub 2} concentration, making conventional flask sampling hard or impossible for radiocarbon studies. The present system captures the CO{sub 2} selectively to cartridges containing 13X molecular sieve material. The sampling does not introduce significant under-pressures or significant losses of moisture to the target system, making it suitable for most environmental targets. The system also incorporates a significantly larger sieve container for the removal of CO{sub 2} from chambers prior to the CO{submore » 2} build-up phase and sampling. In addition, both the CO{sub 2} and H{sub 2}O content of the sample gas are measured continuously. This enables in situ estimation of the amount of collected CO{sub 2} and the determination of CO{sub 2} flux to a chamber. The portable sampling system is described in detail and tests for the reliability of the method are presented.« less

Remote water monitoring system

NASA Technical Reports Server (NTRS)

Grana, D. C.; Haynes, D. P. (Inventor)

1978-01-01

A remote water monitoring system is described that integrates the functions of sampling, sample preservation, sample analysis, data transmission and remote operation. The system employs a floating buoy carrying an antenna connected by lines to one or more sampling units containing several sample chambers. Receipt of a command signal actuates a solenoid to open an intake valve outward from the sampling unit and communicates the water sample to an identifiable sample chamber. Such response to each signal receipt is repeated until all sample chambers are filled in a sample unit. Each sample taken is analyzed by an electrochemical sensor for a specific property and the data obtained is transmitted to a remote sending and receiving station. Thereafter, the samples remain isolated in the sample chambers until the sampling unit is recovered and the samples removed for further laboratory analysis.

40 CFR 86.110-94 - Exhaust gas sampling system; diesel-cycle vehicles, and Otto-cycle vehicles requiring particulate...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Exhaust gas sampling system; diesel... Heavy-Duty Vehicles; Test Procedures § 86.110-94 Exhaust gas sampling system; diesel-cycle vehicles, and..., this is indicated by the statement “[Reserved].” (a) General. The exhaust gas sampling system described...

21 CFR 864.3260 - OTC test sample collection systems for drugs of abuse testing.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false OTC test sample collection systems for drugs of... Instrumentation and Accessories § 864.3260 OTC test sample collection systems for drugs of abuse testing. (a) Identification. An over-the-counter (OTC) test sample collection system for drugs of abuse testing is a device...

46 CFR 161.002-15 - Sample extraction smoke detection systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 6 2010-10-01 2010-10-01 false Sample extraction smoke detection systems. 161.002-15..., CONSTRUCTION, AND MATERIALS: SPECIFICATIONS AND APPROVAL ELECTRICAL EQUIPMENT Fire-Protective Systems § 161.002-15 Sample extraction smoke detection systems. The smoke detecting system must consist of a means for...

Invention and validation of an automated camera system that uses optical character recognition to identify patient name mislabeled samples.

PubMed

Hawker, Charles D; McCarthy, William; Cleveland, David; Messinger, Bonnie L

2014-03-01

Mislabeled samples are a serious problem in most clinical laboratories. Published error rates range from 0.39/1000 to as high as 1.12%. Standardization of bar codes and label formats has not yet achieved the needed improvement. The mislabel rate in our laboratory, although low compared with published rates, prompted us to seek a solution to achieve zero errors. To reduce or eliminate our mislabeled samples, we invented an automated device using 4 cameras to photograph the outside of a sample tube. The system uses optical character recognition (OCR) to look for discrepancies between the patient name in our laboratory information system (LIS) vs the patient name on the customer label. All discrepancies detected by the system's software then require human inspection. The system was installed on our automated track and validated with production samples. We obtained 1 009 830 images during the validation period, and every image was reviewed. OCR passed approximately 75% of the samples, and no mislabeled samples were passed. The 25% failed by the system included 121 samples actually mislabeled by patient name and 148 samples with spelling discrepancies between the patient name on the customer label and the patient name in our LIS. Only 71 of the 121 mislabeled samples detected by OCR were found through our normal quality assurance process. We have invented an automated camera system that uses OCR technology to identify potential mislabeled samples. We have validated this system using samples transported on our automated track. Full implementation of this technology offers the possibility of zero mislabeled samples in the preanalytic stage.

Contained radiological analytical chemistry module

DOEpatents

Barney, David M.

1989-01-01

A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

Contained radiological analytical chemistry module

DOEpatents

Barney, David M.

1990-01-01

A system which provides analytical determination of a plurality of water chemistry parameters with respect to water samples subject to radiological contamination. The system includes a water sample analyzer disposed within a containment and comprising a sampling section for providing predetermined volumes of samples for analysis; a flow control section for controlling the flow through the system; and a gas analysis section for analyzing samples provided by the sampling system. The sampling section includes a controllable multiple port valve for, in one position, metering out sample of a predetermined volume and for, in a second position, delivering the material sample for analysis. The flow control section includes a regulator valve for reducing the pressure in a portion of the system to provide a low pressure region, and measurement devices located in the low pressure region for measuring sample parameters such as pH and conductivity, at low pressure. The gas analysis section which is of independent utility provides for isolating a small water sample and extracting the dissolved gases therefrom into a small expansion volume wherein the gas pressure and thermoconductivity of the extracted gas are measured.

Two-Stage Variable Sample-Rate Conversion System

NASA Technical Reports Server (NTRS)

Tkacenko, Andre

2009-01-01

A two-stage variable sample-rate conversion (SRC) system has been pro posed as part of a digital signal-processing system in a digital com munication radio receiver that utilizes a variety of data rates. The proposed system would be used as an interface between (1) an analog- todigital converter used in the front end of the receiver to sample an intermediatefrequency signal at a fixed input rate and (2) digita lly implemented tracking loops in subsequent stages that operate at v arious sample rates that are generally lower than the input sample r ate. This Two-Stage System would be capable of converting from an input sample rate to a desired lower output sample rate that could be var iable and not necessarily a rational fraction of the input rate.

INCORPORATING PRIOR KNOWLEDGE IN ENVIRONMENTAL SAMPLING: RANKED SET SAMPLING AND OTHER DOUBLE SAMPLING PROCEDURES

EPA Science Inventory

Environmental sampling can be difficult and expensive to carry out. Those taking the samples would like to integrate their knowledge of the system of study or their judgment about the system into the sample selection process to decrease the number of necessary samples. However,...

A Sample Handling System for Mars Sample Return - Design and Status

NASA Astrophysics Data System (ADS)

Allouis, E.; Renouf, I.; Deridder, M.; Vrancken, D.; Gelmi, R.; Re, E.

2009-04-01

A mission to return atmosphere and soil samples form the Mars is highly desired by planetary scientists from around the world and space agencies are starting preparation for the launch of a sample return mission in the 2020 timeframe. Such a mission would return approximately 500 grams of atmosphere, rock and soil samples to Earth by 2025. Development of a wide range of new technology will be critical to the successful implementation of such a challenging mission. Technical developments required to realise the mission include guided atmospheric entry, soft landing, sample handling robotics, biological sealing, Mars atmospheric ascent sample rendezvous & capture and Earth return. The European Space Agency has been performing system definition studies along with numerous technology development studies under the framework of the Aurora programme. Within the scope of these activities Astrium has been responsible for defining an overall sample handling architecture in collaboration with European partners (sample acquisition and sample capture, Galileo Avionica; sample containment and automated bio-sealing, Verhaert). Our work has focused on the definition and development of the robotic systems required to move the sample through the transfer chain. This paper presents the Astrium team's high level design for the surface transfer system and the orbiter transfer system. The surface transfer system is envisaged to use two robotic arms of different sizes to allow flexible operations and to enable sample transfer over relatively large distances (~2 to 3 metres): The first to deploy/retract the Drill Assembly used for sample collection, the second for the transfer of the Sample Container (the vessel containing all the collected samples) from the Drill Assembly to the Mars Ascent Vehicle (MAV). The sample transfer actuator also features a complex end-effector for handling the Sample Container. The orbiter transfer system will transfer the Sample Container from the capture mechanism through a bio-sealing system to the Earth Return Capsule (ERC) and has distinctly different requirements from the surface transfer system. The operations required to transfer the samples to the ERC are clearly defined and make use of mechanisms specifically designed for the job rather than robotic arms. Though it is mechanical rather than robotic, the design of the orbiter transfer system is very complex in comparison to most previous missions to fulfil all the scientific and technological requirements. Further mechanisms will be required to lock the samples into the ERC and to close the door at the rear of the ERC through which the samples have been inserted. Having performed this overall definition study, Astrium is now leading the next step of the development of the MSR sample handling: the Mars Surface Sample Transfer and Manipulation project (MSSTM). Organised in two phases, the project will re-evaluate in phase 1 the output of the previous study in the light of new inputs (e.g. addition of a rover) and investigate further the architectures and systems involved in the sample transfer chain while identifying the critical technologies. The second phase of the project will concentrate on the prototyping of a number of these key technologies with the goal of providing an end-to end validation of the surface sample transfer concept.

40 CFR 63.1032 - Sampling connection systems standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Sampling connection systems standards... (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 2 Standards § 63.1032 Sampling.... Each sampling connection system shall be equipped with a closed-purge, closed-loop, or closed vent...

A Consistent System for Coding Laboratory Samples

NASA Astrophysics Data System (ADS)

Sih, John C.

1996-07-01

A formal laboratory coding system is presented to keep track of laboratory samples. Preliminary useful information regarding the sample (origin and history) is gained without consulting a research notebook. Since this system uses and retains the same research notebook page number for each new experiment (reaction), finding and distinguishing products (samples) of the same or different reactions becomes an easy task. Using this system multiple products generated from a single reaction can be identified and classified in a uniform fashion. Samples can be stored and filed according to stage and degree of purification, e.g. crude reaction mixtures, recrystallized samples, chromatographed or distilled products.

Tests of a High Temperature Sample Conditioner for the Waste Treatment Plant LV-S2, LV-S3, HV-S3A and HV-S3B Exhaust Systems

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

Flaherty, Julia E.; Glissmeyer, John A.

2015-03-18

Tests were performed to evaluate a sample conditioning unit for stack monitoring at Hanford Tank Waste Treatment and Immobilization Plant (WTP) exhaust stacks with elevated air temperatures. The LV-S2, LV-S3, HV-S3A and HV-S3B exhaust stacks are expected to have elevated air temperature and dew point. At these emission points, exhaust temperatures are too high to deliver the air sample directly to the required stack monitoring equipment. As a result, a sample conditioning system is considered to cool and dry the air prior to its delivery to the stack monitoring system. The method proposed for the sample conditioning is a dilutionmore » system that will introduce cooler, dry air to the air sample stream. This method of sample conditioning is meant to reduce the sample temperature while avoiding condensation of moisture in the sample stream. An additional constraint is that the ANSI/HPS N13.1-1999 standard states that at least 50% of the 10 μm aerodynamic diameter (AD) particles present in the stack free stream must be delivered to the sample collector. In other words, depositional loss of particles should be limited to 50% in the sampling, transport, and conditioning systems. Based on estimates of particle penetration through the LV-S3 sampling system, the diluter should perform with about 80% penetration or better to ensure that the total sampling system passes the 50% or greater penetration criterion.« less

Phase II test plan for the evaluation of the performance of container filling systems

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

BOGER, R.M.

The PHMC will provide tank wastes for final treatment by BNFL from Hanford's waste tanks. Concerns about the ability for ''grab'' sampling to provide large volumes of representative waste samples has led to the development of a nested, fixed-depth sampling system. Preferred concepts for filling sample containers that meet RCRA organic sample criteria were identified by a PHMC Decision Board. These systems will replace the needle based sampling ''T'' that is currently on the sampling system. This test plan document identifies cold tests with simulants that will demonstrate the preferred bottle filling concepts abilities to provide representative waste samples andmore » will meet RCRA criteria. Additional tests are identified that evaluate the potential for cross-contamination between samples and the ability for the system to decontaminate surfaces which have contacted tank wastes. These tests will be performed with kaolid/water and sand/water slurry simulants in the test rig that was used by AEAT to complete Phase 1 tests in FY 1999.« less

40 CFR 1065.1105 - Sampling system design.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Sampling system design. 1065.1105... Compounds § 1065.1105 Sampling system design. (a) General. We recommend that you design your SVOC batch... practical, adjust sampling times based on the emission rate of target analytes from the engine to obtain...

System automatically supplies precise analytical samples of high-pressure gases

NASA Technical Reports Server (NTRS)

Langdon, W. M.

1967-01-01

High-pressure-reducing and flow-stabilization system delivers analytical gas samples from a gas supply. The system employs parallel capillary restrictors for pressure reduction and downstream throttling valves for flow control. It is used in conjunction with a sampling valve and minimizes alterations of the sampled gas.

40 CFR 141.707 - Grandfathering previously collected data.

Code of Federal Regulations, 2010 CFR

2010-07-01

... requirements of § 141.701(a) when the system does not have corresponding E. coli and turbidity samples. A system that grandfathers Cryptosporidium samples without E. coli and turbidity samples is not required to collect E. coli and turbidity samples when the system completes the requirements for Cryptosporidium...

40 CFR 141.707 - Grandfathering previously collected data.

Code of Federal Regulations, 2011 CFR

2011-07-01

... requirements of § 141.701(a) when the system does not have corresponding E. coli and turbidity samples. A system that grandfathers Cryptosporidium samples without E. coli and turbidity samples is not required to collect E. coli and turbidity samples when the system completes the requirements for Cryptosporidium...

40 CFR 63.166 - Standards: Sampling connection systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... defined in 40 CFR part 261. (c) In-situ sampling systems and sampling systems without purges are exempt..., closed-loop, or closed-vent system, except as provided in § 63.162(b) of this subpart. Gases displaced...-purge, closed-loop, or closed-vent system as required in paragraph (a) of this section shall: (1) Return...

Improvement of a wind-tunnel sampling system for odour and VOCs.

PubMed

Wang, X; Jiang, J; Kaye, R

2001-01-01

Wind-tunnel systems are widely used for collecting odour emission samples from surface area sources. Consequently, a portable wind-tunnel system was developed at the University of New South Wales that was easy to handle and suitable for sampling from liquid surfaces. Development work was undertaken to ensure even air-flows above the emitting surface and to optimise air velocities to simulate real situations. However, recovery efficiencies for emissions have not previously been studied for wind-tunnel systems. A series of experiments was carried out for determining and improving the recovery rate of the wind-tunnel sampling system by using carbon monoxide as a tracer gas. It was observed by mass balance that carbon monoxide recovery rates were initially only 37% to 48% from a simulated surface area emission source. It was therefore apparent that further development work was required to improve recovery efficiencies. By analysing the aerodynamic character of air movement and CO transportation inside the wind-tunnel, it was determined that the apparent poor recoveries resulted from uneven mixing at the sample collection point. A number of modifications were made for the mixing chamber of the wind-tunnel system. A special sampling chamber extension and a sampling manifold with optimally distributed sampling orifices were developed for the wind-tunnel sampling system. The simulation experiments were repeated with the new sampling system. Over a series of experiments, the recovery efficiency of sampling was improved to 83-100% with an average of 90%, where the CO tracer gas was introduced at a single point and 92-102% with an average of 97%, where the CO tracer gas was introduced along a line transverse to the sweep air. The stability and accuracy of the new system were determined statistically and are reported.

Sample Manipulation System for Sample Analysis at Mars

NASA Technical Reports Server (NTRS)

Mumm, Erik; Kennedy, Tom; Carlson, Lee; Roberts, Dustyn

2008-01-01

The Sample Analysis at Mars (SAM) instrument will analyze Martian samples collected by the Mars Science Laboratory Rover with a suite of spectrometers. This paper discusses the driving requirements, design, and lessons learned in the development of the Sample Manipulation System (SMS) within SAM. The SMS stores and manipulates 74 sample cups to be used for solid sample pyrolysis experiments. Focus is given to the unique mechanism architecture developed to deliver a high packing density of sample cups in a reliable, fault tolerant manner while minimizing system mass and control complexity. Lessons learned are presented on contamination control, launch restraint mechanisms for fragile sample cups, and mechanism test data.

The Sample Handling System for the Mars Icebreaker Life Mission: from Dirt to Data

NASA Technical Reports Server (NTRS)

Dave, Arwen; Thompson, Sarah J.; McKay, Christopher P.; Stoker, Carol R.; Zacny, Kris; Paulsen, Gale; Mellerowicz, Bolek; Glass, Brian J.; Wilson, David; Bonaccorsi, Rosalba;

Generic particulate-monitoring system for retrofit to Hanford exhaust stacks

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

Camman, J.W.; Carbaugh, E.H.

1982-11-01

Evaluations of 72 sampling and monitoring systems were performed at Hanford as the initial phase of a program to upgrade such systems. Each evaluation included determination of theoretical sampling efficiencies for particle sizes ranging from 0.5 to 10 micrometers aerodynamic equivalent diameter, addressing anisokinetic bias, sample transport line losses, and collector device efficiency. Upgrades needed to meet current Department of Energy guidance for effluent sampling and monitoring were identified, and a cost for each upgrade was estimated. A relative priority for each system's upgrade was then established based on evaluation results, current operational status, and future plans for the facilitymore » being exhausted. Common system upgrade requirements lead to the development of a generic design for common components of an exhaust stack sampling and monitoring system for airborne radioactive particulates. The generic design consists of commercially available off-the-shelf components to the extent practical and will simplify future stack sampling and monitoring system design, fabrication, and installation efforts. Evaluation results and their significance to system upgrades are empasized. A brief discussion of the analytical models used and experience to date with the upgrade program is included. Development of the generic stack sampling and monitoring system design is outlined. Generic system design features and limitations are presented. Requirements for generic system retrofitting to existing exhaust stacks are defined and benefits derived from generic system application are discussed.« less

Controls on Ecosystem and Root Respiration in an Alaskan Peatland

NASA Astrophysics Data System (ADS)

McConnell, N. A.; McGuire, A. D.; Harden, J. W.; Kane, E. S.; Turetsky, M. R.

2010-12-01

Boreal ecosystems cover 14% of the vegetated surface on earth and account for 25-30% of the world’s soil carbon (C), mainly due to large carbon stocks in deep peat and frozen soil layers. While peatlands have served as historical sinks of carbon, global climate change may trigger re-release of C to the atmosphere and may turn these ecosystems into net C sources. Rates of C release from a peatland are determined by regional climate and local biotic and abiotic factors such as vegetation cover, thaw depth, and peat thickness. Soil CO2 fluxes are driven by both autotrophic (plant) respiration and heterotrophic (microbial) respiration. Thus, changes in plant and microbial activity in the soil will impact CO2 emissions from peatlands. In this study, we explored environmental and vegetation controls on ecosystem respiration and root respiration in a variety of wetland sites. The study was conducted at the Alaskan Peatland Experiment (APEX; www.uoguelph.ca/APEX) sites in the Bonanza Creek Experimental Forest located 35 km southwest of Fairbanks Alaska. We measured ecosystem respiration, root respiration, and monitored a suite of environmental variables along a vegetation and soil moisture gradient including a black spruce stand with permafrost, a shrubby site with permafrost, a tussock grass site, and a herbaceous open rich fen. Within the rich fen, we have been conducting water table manipulations including a control, lowered, and raised water table treatment. In each of our sites, we measured total ecosystem respiration using static chambers and root respiration by harvesting roots from the uppermost 20 cm and placing them in a root cuvette to obtain a root flux. Ecosystem respiration (ER) on a μmol/m2/sec basis varied across sites. Water table was a significant predictor of ER at the lowered manipulation site and temperature was a strong predictor at the control site in the rich fen. Water table and temperature were both significant predictors of ER at the raised manipulation site. Root respiration fluxes on a ppm CO2/sec/g dry mass basis were highest for herbaceous species, which dominated the open rich fen sites. Root respiration flux was significantly lower in tree-dominated black spruce sites. It appears that the variation in root respiration explains the variation in ER between herbaceous and tree-dominated systems. Therefore an important next step is to partition ER into heterotrophic and autotrophic components across these ecosystems. This in turn will provide a better assessment of peatland C responses to global climate change.

Application of the BioMek 2000 Laboratory Automation Workstation and the DNA IQ System to the extraction of forensic casework samples.

PubMed

Greenspoon, Susan A; Ban, Jeffrey D; Sykes, Karen; Ballard, Elizabeth J; Edler, Shelley S; Baisden, Melissa; Covington, Brian L

2004-01-01

Robotic systems are commonly utilized for the extraction of database samples. However, the application of robotic extraction to forensic casework samples is a more daunting task. Such a system must be versatile enough to accommodate a wide range of samples that may contain greatly varying amounts of DNA, but it must also pose no more risk of contamination than the manual DNA extraction methods. This study demonstrates that the BioMek 2000 Laboratory Automation Workstation, used in combination with the DNA IQ System, is versatile enough to accommodate the wide range of samples typically encountered by a crime laboratory. The use of a silica coated paramagnetic resin, as with the DNA IQ System, facilitates the adaptation of an open well, hands off, robotic system to the extraction of casework samples since no filtration or centrifugation steps are needed. Moreover, the DNA remains tightly coupled to the silica coated paramagnetic resin for the entire process until the elution step. A short pre-extraction incubation step is necessary prior to loading samples onto the robot and it is at this step that most modifications are made to accommodate the different sample types and substrates commonly encountered with forensic evidentiary samples. Sexual assault (mixed stain) samples, cigarette butts, blood stains, buccal swabs, and various tissue samples were successfully extracted with the BioMek 2000 Laboratory Automation Workstation and the DNA IQ System, with no evidence of contamination throughout the extensive validation studies reported here.

Characterization engineering status report october 1998 - december 1998

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

BOGER, R.M.

1999-05-13

Characterization Engineering (CE) continues to make progress in support of the project goal of characterizing the Hanford high-level waste tanks. Two core sampling systems were operational during this reporting period-push mode core sampling system No. 1 and rotary mode core sampling system No. 4. The availability average for core sampling systems No. 1 , No. 3 and No. 4, combined, was 45 percent, down from 79percent for the previous quarter and 58 percent for FY 1998. System No. 2 did not have scope during the quarter, and availability was not hacked. System No. 3 was out of service the entiremore » quarter for corrective maintenance. Two tanks were core sampled during the reporting period, and 24 samples were retrieved. Core sample recovery increased slightly during the quarter. System No. 1 average sample recovery increased from 80percent to 81 percent, The rotary mode core sampling average recovery increased to 62 percent from 55 percent for the previous quarter. sampling six tanks, one more than scheduled. Vapor Sampling was utilized in support of the sluicing of tank 241-C-106 and for emissions monitoring of three exhaust stacks. Increased support was provided for Vapor Sampling the Standard Hydrogen Monitoring Systems. The sampling was necessary due to freezing problems with the field-installed systems. Preparations are continuing for the Light-Duty Utility Arm (LDUA) deployment with configuration and minor hardware upgrades. The LDUA Operational Readiness Review continues. The oversight of the Nested, Fixed-Depth Sampler system development has started to increase in order to ensure that a usable system is received when the project is completed. To improve configuration control, 92 drawing sheet revisions were completed along with the generation of nine new drawing sheets. The number of outstanding Engineering Change Notices increased slightly because of the addition of more drawings into the project. continues to develop. Organizational responsibilities are being identified and documented as well as the scope and deliverables. Finishing Plant was completed, and the final reviews to authorize starting work have begun. Significant progress was made in other areas as well. Grab Sampling completed The stewardship of the Long Length Contaminated Equipment Removal equipment The engineering and work planning for opening tank 241-2361 at the Plutonium.« less

Micro injector sample delivery system for charged molecules

DOEpatents

Davidson, James C.; Balch, Joseph W.

1999-11-09

A micro injector sample delivery system for charged molecules. The injector is used for collecting and delivering controlled amounts of charged molecule samples for subsequent analysis. The injector delivery system can be scaled to large numbers (>96) for sample delivery to massively parallel high throughput analysis systems. The essence of the injector system is an electric field controllable loading tip including a section of porous material. By applying the appropriate polarity bias potential to the injector tip, charged molecules will migrate into porous material, and by reversing the polarity bias potential the molecules are ejected or forced away from the tip. The invention has application for uptake of charged biological molecules (e.g. proteins, nucleic acids, polymers, etc.) for delivery to analytical systems, and can be used in automated sample delivery systems.

Representation of solid and nutrient concentrations in irrigation water from tailwater recovery systems by surface water grab samples

USDA-ARS?s Scientific Manuscript database

Tailwater recovery (TWR) systems are being implemented on agricultural landscapes to create an additional source of irrigation water. Existing studies have sampled TWR systems using grab samples; however, the applicability of solids and nutrient concentrations in these samples to water being irrigat...

40 CFR 86.210-08 - Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Exhaust gas sampling system; Diesel... Vehicles; Cold Temperature Test Procedures § 86.210-08 Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements. (a) General applicability. The exhaust gas sampling...

40 CFR 86.210-08 - Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Exhaust gas sampling system; Diesel... Vehicles; Cold Temperature Test Procedures § 86.210-08 Exhaust gas sampling system; Diesel-cycle vehicles not requiring particulate emissions measurements. (a) General applicability. The exhaust gas sampling...

40 CFR 265.1055 - Standards: Sampling connection systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... with the requirements of § 265.1060 of this subpart. (c) In-situ sampling systems and sampling systems... required in paragraph (a) of this section shall: (1) Return the purged process fluid directly to the...

40 CFR 265.1055 - Standards: Sampling connection systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

... with the requirements of § 265.1060 of this subpart. (c) In-situ sampling systems and sampling systems... required in paragraph (a) of this section shall: (1) Return the purged process fluid directly to the...

40 CFR 265.1055 - Standards: Sampling connection systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

... with the requirements of § 265.1060 of this subpart. (c) In-situ sampling systems and sampling systems... required in paragraph (a) of this section shall: (1) Return the purged process fluid directly to the...

Baseline Design Compliance Matrix for the Rotary Mode Core Sampling System

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

LECHELT, J.A.

2000-10-17

The purpose of the design compliance matrix (DCM) is to provide a single-source document of all design requirements associated with the fifteen subsystems that make up the rotary mode core sampling (RMCS) system. It is intended to be the baseline requirement document for the RMCS system and to be used in governing all future design and design verification activities associated with it. This document is the DCM for the RMCS system used on Hanford single-shell radioactive waste storage tanks. This includes the Exhauster System, Rotary Mode Core Sample Trucks, Universal Sampling System, Diesel Generator System, Distribution Trailer, X-Ray Cart System,more » Breathing Air Compressor, Nitrogen Supply Trailer, Casks and Cask Truck, Service Trailer, Core Sampling Riser Equipment, Core Sampling Support Trucks, Foot Clamp, Ramps and Platforms and Purged Camera System. Excluded items are tools such as light plants and light stands. Other items such as the breather inlet filter are covered by a different design baseline. In this case, the inlet breather filter is covered by the Tank Farms Design Compliance Matrix.« less

Study on sampling of continuous linear system based on generalized Fourier transform

NASA Astrophysics Data System (ADS)

Li, Huiguang

2003-09-01

In the research of signal and system, the signal's spectrum and the system's frequency characteristic can be discussed through Fourier Transform (FT) and Laplace Transform (LT). However, some singular signals such as impulse function and signum signal don't satisfy Riemann integration and Lebesgue integration. They are called generalized functions in Maths. This paper will introduce a new definition -- Generalized Fourier Transform (GFT) and will discuss generalized function, Fourier Transform and Laplace Transform under a unified frame. When the continuous linear system is sampled, this paper will propose a new method to judge whether the spectrum will overlap after generalized Fourier transform (GFT). Causal and non-causal systems are studied, and sampling method to maintain system's dynamic performance is presented. The results can be used on ordinary sampling and non-Nyquist sampling. The results also have practical meaning on research of "discretization of continuous linear system" and "non-Nyquist sampling of signal and system." Particularly, condition for ensuring controllability and observability of MIMO continuous systems in references 13 and 14 is just an applicable example of this paper.

On the continuous dependence with respect to sampling of the linear quadratic regulator problem for distributed parameter systems

NASA Technical Reports Server (NTRS)

Rosen, I. G.; Wang, C.

1990-01-01

The convergence of solutions to the discrete or sampled time linear quadratic regulator problem and associated Riccati equation for infinite dimensional systems to the solutions to the corresponding continuous time problem and equation, as the length of the sampling interval (the sampling rate) tends toward zero (infinity) is established. Both the finite and infinite time horizon problems are studied. In the finite time horizon case, strong continuity of the operators which define the control system and performance index together with a stability and consistency condition on the sampling scheme are required. For the infinite time horizon problem, in addition, the sampled systems must be stabilizable and detectable, uniformly with respect to the sampling rate. Classes of systems for which this condition can be verified are discussed. Results of numerical studies involving the control of a heat/diffusion equation, a hereditary of delay system, and a flexible beam are presented and discussed.

On the continuous dependence with respect to sampling of the linear quadratic regulator problem for distributed parameter system

NASA Technical Reports Server (NTRS)

Rosen, I. G.; Wang, C.

1992-01-01

The convergence of solutions to the discrete- or sampled-time linear quadratic regulator problem and associated Riccati equation for infinite-dimensional systems to the solutions to the corresponding continuous time problem and equation, as the length of the sampling interval (the sampling rate) tends toward zero(infinity) is established. Both the finite-and infinite-time horizon problems are studied. In the finite-time horizon case, strong continuity of the operators that define the control system and performance index, together with a stability and consistency condition on the sampling scheme are required. For the infinite-time horizon problem, in addition, the sampled systems must be stabilizable and detectable, uniformly with respect to the sampling rate. Classes of systems for which this condition can be verified are discussed. Results of numerical studies involving the control of a heat/diffusion equation, a hereditary or delay system, and a flexible beam are presented and discussed.

Molecular-beam gas-sampling system

NASA Technical Reports Server (NTRS)

Young, W. S.; Knuth, E. L.

1972-01-01

A molecular beam mass spectrometer system for rocket motor combustion chamber sampling is described. The history of the sampling system is reviewed. The problems associated with rocket motor combustion chamber sampling are reported. Several design equations are presented. The results of the experiments include the effects of cooling water flow rates, the optimum separation gap between the end plate and sampling nozzle, and preliminary data on compositions in a rocket motor combustion chamber.

47 CFR 73.68 - Sampling systems for antenna monitors.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 4 2014-10-01 2014-10-01 false Sampling systems for antenna monitors. 73.68... RADIO BROADCAST SERVICES AM Broadcast Stations § 73.68 Sampling systems for antenna monitors. (a) Each AM station permittee authorized to construct a new directional antenna system which will be subject...

47 CFR 73.68 - Sampling systems for antenna monitors.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 4 2013-10-01 2013-10-01 false Sampling systems for antenna monitors. 73.68... RADIO BROADCAST SERVICES AM Broadcast Stations § 73.68 Sampling systems for antenna monitors. (a) Each AM station permittee authorized to construct a new directional antenna system which will be subject...

47 CFR 73.68 - Sampling systems for antenna monitors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Sampling systems for antenna monitors. 73.68... RADIO BROADCAST SERVICES AM Broadcast Stations § 73.68 Sampling systems for antenna monitors. (a) Each AM station permittee authorized to construct a new directional antenna system which will be subject...

47 CFR 73.68 - Sampling systems for antenna monitors.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 4 2012-10-01 2012-10-01 false Sampling systems for antenna monitors. 73.68... RADIO BROADCAST SERVICES AM Broadcast Stations § 73.68 Sampling systems for antenna monitors. (a) Each AM station permittee authorized to construct a new directional antenna system which will be subject...

47 CFR 73.68 - Sampling systems for antenna monitors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false Sampling systems for antenna monitors. 73.68... RADIO BROADCAST SERVICES AM Broadcast Stations § 73.68 Sampling systems for antenna monitors. (a) Each AM station permittee authorized to construct a new directional antenna system which will be subject...

Fluid sample collection and distribution system. [qualitative analysis of aqueous samples from several points

NASA Technical Reports Server (NTRS)

Brooks, R. L. (Inventor)

1979-01-01

A multipoint fluid sample collection and distribution system is provided wherein the sample inputs are made through one or more of a number of sampling valves to a progressive cavity pump which is not susceptible to damage by large unfiltered particles. The pump output is through a filter unit that can provide a filtered multipoint sample. An unfiltered multipoint sample is also provided. An effluent sample can be taken and applied to a second progressive cavity pump for pumping to a filter unit that can provide one or more filtered effluent samples. The second pump can also provide an unfiltered effluent sample. Means are provided to periodically back flush each filter unit without shutting off the whole system.

Application of the BAX for screening/genus Listeria polymerase chain reaction system for monitoring Listeria species in cold-smoked fish and in the smoked fish processing environment.

PubMed

Norton, D M; McCamey, M; Boor, K J; Wiedmann, M

2000-03-01

The cold-smoked fish industry was used as a model for the development of a system for monitoring Listeria spp. in foods and in the food processing environment. A total of 214 samples including raw fish, fish during the cold-smoking process, finished product, and environmental samples were collected from three processing facilities over two visits to each facility. Samples were screened for Listeria spp. using the BAX for Screening/genus Listeria polymerase chain reaction system (PCR) and by culture. Listeria spp., confirmed by the API Listeria test strip or by a PCR assay targeting the L. monocytogenes hlyA gene, were isolated from a total of 89 (41.6%) samples. Of these, 80 samples also tested positive for Listeria spp. using the BAX system. Specifically, 42 (55.3%) environmental samples (n = 76), 11 (25.6%) raw materials samples (n = 43), 20 (35.1%) samples from fish in various stages of processing (n = 57), and 7 (18.4%) finished product samples (n = 38) tested positive for Listeria spp. using the BAX system. Five (4.0%) of the 125 culture-negative samples yielded BAX system-positive results. Listeria isolates from each of nine culture-positive/BAX system-negative samples yielded a positive reaction when tested in pure culture by the BAX system, suggesting that our false-negative results were likely due to the presence of low Listeria numbers in the initial enrichment as opposed to nonreacting isolates. The employment of alternative enrichment protocols, such as the two-step enrichment recommended by the manufacturer, may increase the sensitivity of the assay.

Potentiometric chip-based multipumping flow system for the simultaneous determination of fluoride, chloride, pH, and redox potential in water samples.

PubMed

Chango, Gabriela; Palacio, Edwin; Cerdà, Víctor

2018-08-15

A simple potentiometric chip-based multipumping flow system (MPFS) has been developed for the simultaneous determination of fluoride, chloride, pH, and redox potential in water samples. The proposed system was developed by using a poly(methyl methacrylate) chip microfluidic-conductor using the advantages of flow techniques with potentiometric detection. For this purpose, an automatic system has been designed and built by optimizing the variables involved in the process, such as: pH, ionic strength, stirring and sample volume. This system was applied successfully to water samples getting a versatile system with an analysis frequency of 12 samples per hour. Good correlation between chloride and fluoride concentration measured with ISE and ionic chromatography technique suggests satisfactory reliability of the system. Copyright © 2018 Elsevier B.V. All rights reserved.

Global Unique Identification of Geoscience Samples: The International Geo Sample Number (IGSN) and the System for Earth Sample Registration (SESAR)

NASA Astrophysics Data System (ADS)

Lehnert, K. A.; Goldstein, S. L.; Vinayagamoorthy, S.; Lenhardt, W. C.

2005-12-01

Data on samples represent a primary foundation of Geoscience research across disciplines, ranging from the study of climate change, to biogeochemical cycles, to mantle and continental dynamics and are key to our knowledge of the Earth's dynamical systems and evolution. Different data types are generated for individual samples by different research groups, published in different papers, and stored in different databases on a global scale. The utility of these data is critically dependent on their integration. Such integration can be achieved within a Geoscience Cyberinfrastructure, but requires unambiguous identification of samples. Currently, naming of samples is arbitrary and inconsistent and therefore severely limits our ability to share, link, and integrate sample-based data. Major problems include name duplication, and changing of names as a sample is passed along over many years to different investigators. SESAR, the System for Earth Sample Registration (http://www.geosamples.org), addresses this problem by building a registry that generates and administers globally unique identifiers for Geoscience samples: the International Geo Sample Number (IGSN). Implementation of the IGSN in data publication and digital data management will dramatically advance interoperability among information systems for sample-based data, opening an extensive range of new opportunities for discovery and for interdisciplinary approaches in research. The IGSN will also facilitate the ability of investigators to build on previously collected data on samples as new measurements are made or new techniques are developed. With potentially broad application to all types of Geoscience samples, SESAR is global in scope. It is a web-based system that can be easily accessed by individual users through an interactive web interface and by distributed client systems via standard web services. Samples can be registered individually or in batches and at various levels of granularity from entire cores or dredges or sample suites to individual samples to sub-samples such as splits and separates. Relationships between `parent' and `child' samples are tracked. The system generates bar codes that users can download as images for labeling purposes. SESAR released a beta version of the registry in April 2005 that allows users to register a limited range of sample types. Identifiers generated by the beta version will remain valid when SESAR moves into its operational stage. Since then more than 3700 samples have been registered in SESAR. Registration of samples at a central clearinghouse will automatically build a global catalog of Geoscience samples, which will become a hugely valuable resource for the Geoscience community that allows more efficient planning of field and laboratory projects and facilitates sharing of samples, which will help build more comprehensive data sets for individual samples. The SESAR catalog will provide links to sample profiles on external systems that hold data about samples, thereby enabling users to easily obtain complete information about samples.

National accident sampling system sample design, phases 2 and 3 : executive summary

DOT National Transportation Integrated Search

1979-11-01

This report describes the Phase 2 and 3 sample design for the : National Accident Sampling System (NASS). It recommends a procedure : for the first-stage selection of Primary Sampling Units (PSU's) and : the second-stage design for the selection of a...

Apollo Experiment Report: Lunar-Sample Processing in the Lunar Receiving Laboratory High-Vacuum Complex

NASA Technical Reports Server (NTRS)

White, D. R.

1976-01-01

A high-vacuum complex composed of an atmospheric decontamination system, sample-processing chambers, storage chambers, and a transfer system was built to process and examine lunar material while maintaining quarantine status. Problems identified, equipment modifications, and procedure changes made for Apollo 11 and 12 sample processing are presented. The sample processing experiences indicate that only a few operating personnel are required to process the sample efficiently, safely, and rapidly in the high-vacuum complex. The high-vacuum complex was designed to handle the many contingencies, both quarantine and scientific, associated with handling an unknown entity such as the lunar sample. Lunar sample handling necessitated a complex system that could not respond rapidly to changing scientific requirements as the characteristics of the lunar sample were better defined. Although the complex successfully handled the processing of Apollo 11 and 12 lunar samples, the scientific requirement for vacuum samples was deleted after the Apollo 12 mission just as the vacuum system was reaching its full potential.

Birefringence insensitive optical coherence domain reflectometry system

DOEpatents

Everett, Matthew J.; Davis, Joseph G.

2002-01-01

A birefringence insensitive fiber optic optical coherence domain reflectometry (OCDR) system is provided containing non-polarization maintaining (non-PM) fiber in the sample arm and the reference arm without suffering from signal degradation caused by birefringence. The use of non-PM fiber significantly reduces the cost of the OCDR system and provides a disposable or multiplexed section of the sample arm. The dispersion in the reference arm and sample arm of the OCDR system are matched to achieve high resolution imaging. This system is useful in medical applications or for non-medical in situ probes. The disposable section of non-PM fiber in the sample arm can be conveniently replaced when contaminated by a sample or a patient.

40 CFR 91.414 - Raw gaseous exhaust sampling and analytical system description.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Raw gaseous exhaust sampling and... Gaseous Exhaust Test Procedures § 91.414 Raw gaseous exhaust sampling and analytical system description... the component systems. (g) The following requirements must be incorporated in each system used for raw...

40 CFR 91.414 - Raw gaseous exhaust sampling and analytical system description.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Raw gaseous exhaust sampling and... Gaseous Exhaust Test Procedures § 91.414 Raw gaseous exhaust sampling and analytical system description... the component systems. (g) The following requirements must be incorporated in each system used for raw...

46 CFR 161.002-15 - Sample extraction smoke detection systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 6 2014-10-01 2014-10-01 false Sample extraction smoke detection systems. 161.002-15...-15 Sample extraction smoke detection systems. The smoke detecting system must consist of a means for... smoke, together with visual and audible alarms for indicating the presence of smoke. [CGD 94-108, 61 FR...

46 CFR 161.002-15 - Sample extraction smoke detection systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 6 2011-10-01 2011-10-01 false Sample extraction smoke detection systems. 161.002-15...-15 Sample extraction smoke detection systems. The smoke detecting system must consist of a means for... smoke, together with visual and audible alarms for indicating the presence of smoke. [CGD 94-108, 61 FR...

46 CFR 161.002-15 - Sample extraction smoke detection systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 6 2012-10-01 2012-10-01 false Sample extraction smoke detection systems. 161.002-15...-15 Sample extraction smoke detection systems. The smoke detecting system must consist of a means for... smoke, together with visual and audible alarms for indicating the presence of smoke. [CGD 94-108, 61 FR...

46 CFR 161.002-15 - Sample extraction smoke detection systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 6 2013-10-01 2013-10-01 false Sample extraction smoke detection systems. 161.002-15...-15 Sample extraction smoke detection systems. The smoke detecting system must consist of a means for... smoke, together with visual and audible alarms for indicating the presence of smoke. [CGD 94-108, 61 FR...

40 CFR 60.482-5a - Standards: Sampling connection systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 261. (c) In-situ sampling systems and sampling systems without purges are exempt from the requirements... Equipment Leaks of VOC in the Synthetic Organic Chemicals Manufacturing Industry for Which Construction...-vent system, except as provided in § 60.482-1a(c) and paragraph (c) of this section. (b) Each closed...

40 CFR 60.482-5a - Standards: Sampling connection systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 261. (c) In-situ sampling systems and sampling systems without purges are exempt from the requirements... Equipment Leaks of VOC in the Synthetic Organic Chemicals Manufacturing Industry for Which Construction...-vent system, except as provided in § 60.482-1a(c) and paragraph (c) of this section. (b) Each closed...

40 CFR 60.482-5a - Standards: Sampling connection systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 261. (c) In-situ sampling systems and sampling systems without purges are exempt from the requirements... Equipment Leaks of VOC in the Synthetic Organic Chemicals Manufacturing Industry for Which Construction...-vent system, except as provided in § 60.482-1a(c) and paragraph (c) of this section. (b) Each closed...

What is Next? Linking all Samples of Planet Earth.

NASA Astrophysics Data System (ADS)

Wyborn, L. A.; Lehnert, K.; Klump, J. F.; Arko, R. A.; Cox, S. J. D.; Devaraju, A.; Elger, K.; Murphy, F.; Fleischer, D.

2016-12-01

The process of sampling, observing and analyzing physical samples is not unique to the geosciences. Physical sampling (taking specimens) is a fundamental strategy in many natural sciences, typically to support ex-situ observations in laboratories with the goal of characterizing real-world entities or populations. Observations and measurements are made on individual specimens and their derived samples in various ways, with results reported in research publications. Research on an individual sample is often published in numerous articles, based on multiple, potentially unrelated research programs conducted over many years. Even high-volume Earth observation datasets are proxies of real world phenomena and require calibration by measurements made on position located, well described physical samples. Unique, persistent web-compatible identifiers for physical objects and related sampling features are required to ensure their unambiguous citation and connection to related datasets through web identifiers. Identifier systems have been established within specific domains (e.g., bio, geo, hydro) or different sectors (e.g., museums, government agencies, universities), including the International Geo Sample Number (IGSN) in the geosciences, which has been used for rock, fossil, mineral, soil, regolith, fluid, plant and synthetic materials. IGSNs are issued through a governance system that ensures they are globally unique. Each IGSN directs to a digital representation of the physical object via the Handle.net global resolver system, the same system used for resolving DOI. To enable the unique identification of all samples on Planet Earth and of data derived from them, the next step is to ensure IGSNs can either be integrated with comparable identifier systems in other domains/sectors, or introduced into domains that do not have a viable system. A registry of persistent identifier systems for physical samples would allow users to choose which system best suits their needs. Such a registry may also facilitate unifying best practice in these multiple systems to enable consistent referencing of physical samples and of methods used to link digital data to its sources. IGSNs could be extended into other domains, but additional methodologies of sample collection, curation and processing may need to be considered.

Extending the Collection Duration of Breath Samples for Enteric Methane Emission Estimation Using the SF6 Tracer Technique

PubMed Central

Pinares-Patiño, César; Gere, José; Williams, Karen; Gratton, Roberto; Juliarena, Paula; Molano, German; MacLean, Sarah; Sandoval, Edgar; Taylor, Grant; Koolaard, John

2012-01-01

Simple Summary Extended sample collection for the SF6 tracer technique is desirable for extensive grazing systems. Breath samples from eight cows were collected while lucerne silage was fed to achieve fixed intakes among the cows. Samples were collected over a 10-day period, using either apparatuses used in New Zealand (NZL) or Argentina (ARG), and either daily, over two consecutive 5-day periods or over a 10-day period (in duplicate). The NZL system had a greater sampling success and more consistent CH4 emission estimates than the ARG system, with no differences in mean emissions among sample collection periods. This study showed that extended sample collection is feasible, but definitive evaluation under grazing situation is required before a decision on recommendation can be made. Abstract The daily sample collection protocol of the sulphur hexafluoride (SF6) tracer technique for the estimation of methane (CH4) emissions from ruminants may not be practical under extensive grazing systems. Here, under controlled conditions, we evaluated extended periods of sampling as an alternative to daily sample collections. Eight rumen-fistulated cows were housed and fed lucerne silage to achieve common daily feed intakes of 6.4 kg dry matter per cow. Following SF6 permeation tube dosing, eight sampling lines were fitted to the breath collection harness, so that a common gas mix was available to each line. Half of the lines collected samples into PVC yokes using a modified capillary system as commonly used in New Zealand (NZL), and half collected samples into stainless steel cylinders using a ball-bearing flow restrictor as used in Argentina (ARG), all within a 10-day time frame, either daily, across two consecutive 5-day periods or across one 10-day period (in duplicate). The NZL system had greater sampling success (97.3 vs. 79.5%) and yielded more consistent CH4 emission estimates than the ARG system. Emission estimates from NZL daily, NZL 5-day and NZL 10-day samplings were 114, 110 and 111 g d−1, respectively. Extended sample collection protocol may be feasible, but definitive evaluation of this alternative as well as sample collection systems is required under grazing situations before a decision on recommendation can be made. PMID:26486921

Optical tweezers and surface plasmon resonance combination system based on the high numerical aperture lens

NASA Astrophysics Data System (ADS)

Shan, Xuchen; Zhang, Bei; Lan, Guoqiang; Wang, Yiqiao; Liu, Shugang

2015-11-01

Biology and medicine sample measurement takes an important role in the microscopic optical technology. Optical tweezer has the advantage of accurate capture and non-pollution of the sample. The SPR(surface plasmon resonance) sensor has so many advantages include high sensitivity, fast measurement, less consumption of sample and label-free detection of biological sample that the SPR sensing technique has been used for surface topography, analysis of biochemical and immune, drug screening and environmental monitoring. If they combine, they will play an important role in the biological, chemical and other subjects. The system we propose use the multi-axis cage system, by using the methods of reflection and transmiss ion to improve the space utilization. The SPR system and optical tweezer were builtup and combined in one system. The cage of multi-axis system gives full play to its accuracy, simplicity and flexibility. The size of the system is 20 * 15 * 40 cm3 and thus the sample can be replaced to switch between the optical tweezers system and the SPR system in the small space. It means that we get the refractive index of the sample and control the particle in the same system. In order to control the revolving stage, get the picture and achieve the data stored automatically, we write a LabVIEW procedure. Then according to the data from the back focal plane calculate the refractive index of the sample. By changing the slide we can trap the particle as optical tweezer, which makes us measurement and trap the sample at the same time.

Chemical amplification based on fluid partitioning

DOEpatents

Anderson, Brian L [Lodi, CA; Colston, Jr., Billy W.; Elkin, Chris [San Ramon, CA

2006-05-09

A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

The prevalence of deoxynivalenol and its derivatives in the spring wheat grain from different agricultural production systems in Lithuania.

PubMed

Janaviciene, Sigita; Mankeviciene, Audrone; Suproniene, Skaidre; Kochiieru, Yuliia; Keriene, Ilona

2018-02-22

Deoxynivalenol (DON) together with two acetylated derivatives, 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON) occurs in cereal grains and their products. Co-occurrence of DON and acetylated derivatives in cereal grain is detected worldwide. Until now, DON and its derivatives have been considered equally toxic by health authorities. In this study, we analysed 103 samples of spring wheat grain, originating from the fields of different production systems in Lithuania, for the co-occurrence of type-B trichothecenes (DON, 3-ADON, 15-ADON). The samples were classified according to the production system-organic, sustainable and intensive. Mycotoxin levels in the spring wheat grain samples were determined by the HPLC method with UV detection. The type-B trichothecenes were found to be present at higher concentrations in the grain from the intensive production system. Eighty-one percent of the spring wheat grain samples from the intensive production system were co-contaminated with a combination of DON+3-ADON+15-ADON, 1% with DON+3-ADON. Additionally, DON+15-ADON and DON were found in 5% and 10% of the tested samples, respectively. Two percent of the samples were free from mycotoxins. In the grain samples from the sustainable production system, DON and a combination of DON+3-ADON showed a higher incidence - 47% and 23%, respectively. The samples with a combination of DON+3-ADON+15-ADON accounted for 18%. Completely different results were obtained from the analyses of organic grain samples. A large number of the organic spring wheat grain samples were contaminated with DON+3-ADON (55%) or DON (36%). The combination of DON+3-ADON+15-ADON was not present, while DON+15-ADON was present in 9% of the samples tested. The production systems did not lead to significant differences in mycotoxin levels, although a trend toward higher incidence and higher contamination was observed for the samples from the intensive and sustainable production systems.

40 CFR 86.109-94 - Exhaust gas sampling system; Otto-cycle vehicles not requiring particulate emission measurements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... detection for the HPLC analyzer. Sampling systems for all phases shall be identical. (iii) The methanol and... detection for the HPLC analyzer. Sampling systems for all phases shall be identical. (iii) The methanol and...

40 CFR 86.109-94 - Exhaust gas sampling system; Otto-cycle vehicles not requiring particulate emission measurements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... detection for the HPLC analyzer. Sampling systems for all phases shall be identical. (iii) The methanol and... detection for the HPLC analyzer. Sampling systems for all phases shall be identical. (iii) The methanol and...

40 CFR 86.109-94 - Exhaust gas sampling system; Otto-cycle vehicles not requiring particulate emission measurements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... detection for the HPLC analyzer. Sampling systems for all phases shall be identical. (iii) The methanol and... detection for the HPLC analyzer. Sampling systems for all phases shall be identical. (iii) The methanol and...

Mapping Water Level Dynamics over Central Congo River Using PALSAR Images, Envisat Altimetry, and Landsat NDVI Data

NASA Astrophysics Data System (ADS)

Kim, D.; Lee, H.; Jung, H. C.; Beighley, E.; Laraque, A.; Tshimanga, R.; Alsdorf, D. E.

2016-12-01

Rivers and wetlands are very important for ecological habitats, and it plays a key role in providing a source of greenhouse gases (CO2 and CH4). The floodplains ecosystems depend on the process between the vegetation and flood characteristics. The water level is a prerequisite to an understanding of terrestrial water storage and discharge. Despite the lack of in situ data over the Congo Basin, which is the world's third largest in size ( 3.7 million km2), and second only to the Amazon River in discharge ( 40,500 m3 s-1 annual average between 1902 and 2015 in the main Brazzaville-Kinshasa gauging station), the surface water level dynamics in the wetlands have been successfully estimated using satellite altimetry, backscattering coefficients (σ0) from Synthetic Aperture Radar (SAR) images and, interferometric SAR technique. However, the water level estimation of the Congo River remains poorly quantified due to the sparse orbital spacing of radar altimeters. Hence, we essentially have limited information only over the sparsely distributed the so-called "virtual stations". The backscattering coefficients from SAR images have been successfully used to distinguish different vegetation types, to monitor flood conditions, and to access soil moistures over the wetlands. However, σ0 has not been used to measure the water level changes over the open river because of very week return signal due to specular scattering. In this study, we have discovered that changes in σ0 over the Congo River occur mainly due to the water level changes in the river with the existence of the water plants (macrophytes, emergent plants, and submersed plant), depending on the rising and falling stage inside the depression of the "Cuvette Centrale". We expand the finding into generating the multi-temporal water level maps over the Congo River using PALSAR σ0, Envisat altimetry, and Landsat Normalized Difference Vegetation Index (NDVI) data. We also present preliminary estimates of the river discharge using the water level maps.

Soil and water warming accelerates phenology and down-regulation of leaf photosynthesis of rice plants grown under free-air CO2 enrichment (FACE).

PubMed

Adachi, Minaco; Hasegawa, Toshihiro; Fukayama, Hiroshi; Tokida, Takeshi; Sakai, Hidemitsu; Matsunami, Toshinori; Nakamura, Hirofumi; Sameshima, Ryoji; Okada, Masumi

2014-02-01

To enable prediction of future rice production in a changing climate, we need to understand the interactive effects of temperature and elevated [CO2] (E[CO2]). We therefore examined if the effect of E[CO2] on the light-saturated leaf photosynthetic rate (Asat) was affected by soil and water temperature (NT, normal; ET, elevated) under open-field conditions at the rice free-air CO2 enrichment (FACE) facility in Shizukuishi, Japan, in 2007 and 2008. Season-long E[CO2] (+200 µmol mol(-1)) increased Asat by 26%, when averaged over two years, temperature regimes and growth stages. The effect of ET (+2°C) on Asat was not significant at active tillering and heading, but became negative and significant at mid-grain filling; Asat in E[CO2]-ET was higher than in ambient [CO2] (A[CO2])-NT by only 4%. Photosynthetic down-regulation at E[CO2] also became apparent at mid-grain filling; Asat compared at the same [CO2] in the leaf cuvette was significantly lower in plants grown in E[CO2] than in those grown in A[CO2]. The additive effects of E[CO2] and ET decreased Asat by 23% compared with that of A[CO2]-NT plants. Although total crop nitrogen (N) uptake was increased by ET, N allocation to the leaves and to Rubisco was reduced under ET and E[CO2] at mid-grain filling, which resulted in a significant decrease (32%) in the maximum rate of ribulose-1,5-bisphosphate carboxylation on a leaf area basis. Because the change in N allocation was associated with the accelerated phenology in E[CO2]-ET plants, we conclude that soil and water warming accelerates photosynthetic down-regulation at E[CO2].

Application of "FLUOR-P" device for analysis of the space flight effects on the intracellular level.

NASA Astrophysics Data System (ADS)

Grigorieva, Olga; Rudimov, Evgeny; Buravkova, Ludmila; Galchuk, Sergey

The mechanisms of cellular gravisensitivity still remain unclear despite the intensive research in the hypogravity effects on cellular function. In most cell culture experiments on unmanned vehicles "Bion" and "Photon", as well as on the ISS only allow post-flight analysis of biological material, including fixed cells is provided. The dynamic evaluation cellular parameters over a prolonged period of time is not possible. Thus, a promising direction is the development of equipment for onboard autonomous experiments. For this purpose, the SSC RF IBMP RAS has developed "FLUOR-P" device for measurement and recording of the dynamic differential fluorescent signal from nano- and microsized objects of organic and inorganic nature (human and animal cells, unicellular algae, bacteria, cellular organelles suspension) in hermetically sealed cuvettes. Besides, the device allows to record the main physical factors affecting the analyzed object (temperature and gravity loads: position in space, any vector acceleration, shock) in sync with the main measurements. The device is designed to perform long-term programmable autonomous experiments in space flight on biological satellites. The device software of allows to carry out complex experiments using cell. Permanent registration of data on built-in flash will give the opportunity to analyze the dynamics of the estimated parameters. FLUOR-P is designed as a monobloc (5.5 kg weight), 8 functional blocks are located in the inner space of the device. Each registration unit of the FLUOR-P has two channels of fluorescence intensity and excitation light source with the wavelength range from 300 nm to 700 nm. During biosatellite "Photon" flight is supposed to conduct a full analysis of the most important intracellular parameters (mitochondria activity and intracellular pH) dynamics under space flight factors and to assess the possible contribution of temperature on the effects of microgravity. Work is supported by Roskosmos and the Russian Academy of Sciences.

Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments.

PubMed

Gopalakrishnan, V; Subramanian, V; Baskaran, R; Venkatraman, B

2015-07-01

Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in a preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.

Note: Design and development of wireless controlled aerosol sampling network for large scale aerosol dispersion experiments

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

Gopalakrishnan, V.; Subramanian, V.; Baskaran, R.

2015-07-15

Wireless based custom built aerosol sampling network is designed, developed, and implemented for environmental aerosol sampling. These aerosol sampling systems are used in field measurement campaign, in which sodium aerosol dispersion experiments have been conducted as a part of environmental impact studies related to sodium cooled fast reactor. The sampling network contains 40 aerosol sampling units and each contains custom built sampling head and the wireless control networking designed with Programmable System on Chip (PSoC™) and Xbee Pro RF modules. The base station control is designed using graphical programming language LabView. The sampling network is programmed to operate in amore » preset time and the running status of the samplers in the network is visualized from the base station. The system is developed in such a way that it can be used for any other environment sampling system deployed in wide area and uneven terrain where manual operation is difficult due to the requirement of simultaneous operation and status logging.« less

A prototype sensor system for the early detection of microbially linked spoilage in stored wheat grain

NASA Astrophysics Data System (ADS)

de Lacy Costello, B. P. J.; Ewen, R. J.; Gunson, H.; Ratcliffe, N. M.; Sivanand, P. S.; Spencer-Phillips, P. T. N.

2003-04-01

Sensors based on composites of metal oxides were fabricated and tested extensively under high-humidity and high-flow conditions with exposure to vapours reported to increase in the headspace of wheat grain (Triticum aestivum cv Hereward) colonized by fungi. The sensors that exhibited high sensitivity to target vapours combined with high stability were selected for inclusion into a four-sensor array prototype system. A sampling protocol aligned to parallel gas chromatography-mass spectrometry and human olfactory assessment studies was established for use with the sensor system. The sensor system was utilized to assess irradiated wheat samples that had been conditioned to 25% moisture content and inoculated with pathogens known to cause spoilage of grain in storage. These included the fungi Penicillium aurantiogriseum, Penicillium vulpinum, Penicillium verrucosum, Fusarium culmorum, Aspergillus niger, and Aspergillus flavus and the actinomycete, Streptomyces griseus. The sensor system successfully tracked the progress of the infections from a very early stage and the results were compared with human olfactory assessment panels run concurrently. A series of dilution studies were undertaken using previously infected grain mixed with sound grain, to improve the sensitivity and maximize the differentiation of the sensor system. An optimum set of conditions including incubation temperature, incubation time, sampling time, and flow rate were ascertained utilizing this method. The sensor system differentiated samples of sound grain from samples of sound grain with 1% (w/w) fungus infected grain added. Following laboratory trials, the prototype sensor system was evaluated in a commercial wheat grain intake facility. Thresholds calculated from laboratory tests were used to differentiate between sound and infected samples (classified by intake laboratory technicians) collected routinely from trucks delivering grain for use in food manufacture. All samples identified as having an odour-related problem by the intake laboratory gave a total system output above the set threshold and were therefore rejected by the prototype system. A number of samples passed by the intake laboratory were rejected by the prototype system, resulting in what appeared to be false positive results. However, the thresholds were selected on the basis of a limited number of samples and may need to be adjusted to minimize false positives. The output from the sensor system was also compared with moisture content values for the wheat (where available) to demonstrate that the system was not simply measuring differences in moisture. A separate study (carried out at the intake facility) assessed 37 newly harvested wheat samples of different varieties and from different geographic locations within the UK. These samples were analysed by the sensor system, using the same thresholds as before. Six samples rejected by the system were then assessed by the wheat intake laboratory, where only one sample was rejected. This rejected sample had given the highest output when exposed to the sensor system. The commercial trial highlighted the promise of this prototype for the detection of spoilage in wheat grain and a larger trial should ascertain the reliability and long-term stability of the device and therefore confirm its usefulness to the industry.

An error criterion for determining sampling rates in closed-loop control systems

NASA Technical Reports Server (NTRS)

Brecher, S. M.

1972-01-01

The determination of an error criterion which will give a sampling rate for adequate performance of linear, time-invariant closed-loop, discrete-data control systems was studied. The proper modelling of the closed-loop control system for characterization of the error behavior, and the determination of an absolute error definition for performance of the two commonly used holding devices are discussed. The definition of an adequate relative error criterion as a function of the sampling rate and the parameters characterizing the system is established along with the determination of sampling rates. The validity of the expressions for the sampling interval was confirmed by computer simulations. Their application solves the problem of making a first choice in the selection of sampling rates.

A large-scale cryoelectronic system for biological sample banking

NASA Astrophysics Data System (ADS)

Shirley, Stephen G.; Durst, Christopher H. P.; Fuchs, Christian C.; Zimmermann, Heiko; Ihmig, Frank R.

2009-11-01

We describe a polymorphic electronic infrastructure for managing biological samples stored over liquid nitrogen. As part of this system we have developed new cryocontainers and carrier plates attached to Flash memory chips to have a redundant and portable set of data at each sample. Our experimental investigations show that basic Flash operation and endurance is adequate for the application down to liquid nitrogen temperatures. This identification technology can provide the best sample identification, documentation and tracking that brings added value to each sample. The first application of the system is in a worldwide collaborative research towards the production of an AIDS vaccine. The functionality and versatility of the system can lead to an essential optimization of sample and data exchange for global clinical studies.

Controlling aliased dynamics in motion systems? An identification for sampled-data control approach

NASA Astrophysics Data System (ADS)

Oomen, Tom

2014-07-01

Sampled-data control systems occasionally exhibit aliased resonance phenomena within the control bandwidth. The aim of this paper is to investigate the aspect of these aliased dynamics with application to a high performance industrial nano-positioning machine. This necessitates a full sampled-data control design approach, since these aliased dynamics endanger both the at-sample performance and the intersample behaviour. The proposed framework comprises both system identification and sampled-data control. In particular, the sampled-data control objective necessitates models that encompass the intersample behaviour, i.e., ideally continuous time models. Application of the proposed approach on an industrial wafer stage system provides a thorough insight and new control design guidelines for controlling aliased dynamics.

Humidity-controlled preparation of frozen-hydrated biological samples for cryogenic coherent x-ray diffraction microscopy

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

Takayama, Yuki; Nakasako, Masayoshi; RIKEN Harima Institute/SPring-8, 1-1-1 Kouto, Mikaduki, Sayo, Hyogo 679-5148

2012-05-15

Coherent x-ray diffraction microscopy (CXDM) has the potential to visualize the structures of micro- to sub-micrometer-sized biological particles, such as cells and organelles, at high resolution. Toward advancing structural studies on the functional states of such particles, here, we developed a system for the preparation of frozen-hydrated biological samples for cryogenic CXDM experiments. The system, which comprised a moist air generator, microscope, micro-injector mounted on a micromanipulator, custom-made sample preparation chamber, and flash-cooling device, allowed for the manipulation of sample particles in the relative humidity range of 20%-94%rh at 293 K to maintain their hydrated and functional states. Here, wemore » report the details of the system and the operation procedure, including its application to the preparation of a frozen-hydrated chloroplast sample. Sample quality was evaluated through a cryogenic CXDM experiment conducted at BL29XUL of SPring-8. Taking the performance of the system and the quality of the sample, the system was suitable to prepare frozen-hydrated biological samples for cryogenic CXDM experiments.« less

Improving the Acquisition and Management of Sample Curation Data

NASA Technical Reports Server (NTRS)

Todd, Nancy S.; Evans, Cindy A.; Labasse, Dan

2011-01-01

This paper discusses the current sample documentation processes used during and after a mission, examines the challenges and special considerations needed for designing effective sample curation data systems, and looks at the results of a simulated sample result mission and the lessons learned from this simulation. In addition, it introduces a new data architecture for an integrated sample Curation data system being implemented at the NASA Astromaterials Acquisition and Curation department and discusses how it improves on existing data management systems.

Chemical amplification based on fluid partitioning in an immiscible liquid

DOEpatents

Anderson, Brian L.; Colston, Bill W.; Elkin, Christopher J.

2010-09-28

A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

Biofilm monitoring coupon system and method of use

NASA Technical Reports Server (NTRS)

Sauer, Richard L. (Inventor); Flanagan, David T. (Inventor)

1991-01-01

An apparatus and method is disclosed for biofilm monitoring of a water distribution system which includes the mounting of at least one fitting in a wall port of a manifold in the water distribution system with a passage through the fitting in communication. The insertion of a biofilm sampling member is through the fitting with planar sampling surfaces of different surface treatment provided on linearly arrayed sample coupons of the sampling member disposed in the flow stream in edge-on parallel relation to the direction of the flow stream of the manifold under fluid-tight sealed conditions. The sampling member is adapted to be aseptically removed from or inserted in the fitting and manifold under a positive pressure condition and the fitting passage sealed immediately thereafter by appropriate closure means so as to preclude contamination of the water distribution system through the fitting. The apparatus includes means for clamping the sampling member and for establishing electrical continuity between the sampling surfaces and the system for minimizing electropotential effects. The apparatus may also include a plurality of fittings and sampling members mounted on the manifold to permit extraction of the sampling members in a timed sequence throughout the monitoring period.

Systems and methods for sample analysis

DOEpatents

Cooks, Robert Graham; Li, Guangtao; Li, Xin; Ouyang, Zheng

2015-01-13

The invention generally relates to systems and methods for sample analysis. In certain embodiments, the invention provides a system for analyzing a sample that includes a probe including a material connected to a high voltage source, a device for generating a heated gas, and a mass analyzer.

ACS sampling system: design, implementation, and performance evaluation

NASA Astrophysics Data System (ADS)

Di Marcantonio, Paolo; Cirami, Roberto; Chiozzi, Gianluca

2004-09-01

By means of ACS (ALMA Common Software) framework we designed and implemented a sampling system which allows sampling of every Characteristic Component Property with a specific, user-defined, sustained frequency limited only by the hardware. Collected data are sent to various clients (one or more Java plotting widgets, a dedicated GUI or a COTS application) using the ACS/CORBA Notification Channel. The data transport is optimized: samples are cached locally and sent in packets with a lower and user-defined frequency to keep network load under control. Simultaneous sampling of the Properties of different Components is also possible. Together with the design and implementation issues we present the performance of the sampling system evaluated on two different platforms: on a VME based system using VxWorks RTOS (currently adopted by ALMA) and on a PC/104+ embedded platform using Red Hat 9 Linux operating system. The PC/104+ solution offers, as an alternative, a low cost PC compatible hardware environment with free and open operating system.

UHV LT-STM system with Sample and Tip Exchange

NASA Astrophysics Data System (ADS)

Dreyer, Michael; Lee, Jonghee; Wang, Hui; Sullivan, Dan; Barker, Barry

2006-03-01

We developed and built a low temperature scanning tunneling microscope system with ultra high vacuum sample and tip preparation capabilities. The STM is mounted inside an UHV can which is submerged in a He bath cryostat. The cryostat is equipped with two superconducting magnets allowing a maximum in plane field of 2 T and a maximum out of plane field of 9 T. The two fields can be combined to a 1 T vector field. The vacuum can is connected to an UHV system at room temperature consisting of two chambers: One dedicated to transferring samples and tips to the STM, and the other chamber used for tip/sample preparation. It is equipped with two electron beam evaporators, an argon ion sputter gun as well as sample heaters. The whole system is supported by an optical table to decouple the STM from building vibrations. The system was successfully used to study standing electron waves on gold (111) as well as vortices on NbSe2. Details of the microscope, sample and tip handling system, as well as the UHV system will be presented.

Plasma heating for containerless and microgravity materials processing

NASA Technical Reports Server (NTRS)

Leung, Emily W. (Inventor); Man, Kin F. (Inventor)

1994-01-01

A method for plasma heating of levitated samples to be used in containerless microgravity processing is disclosed. A sample is levitated by electrostatic, electromagnetic, aerodynamic, or acoustic systems, as is appropriate for the physical properties of the particular sample. The sample is heated by a plasma torch at atmospheric pressure. A ground plate is provided to help direct the plasma towards the sample. In addition, Helmholtz coils are provided to produce a magnetic field that can be used to spiral the plasma around the sample. The plasma heating system is oriented such that it does not interfere with the levitation system.

System Would Acquire Core and Powder Samples of Rocks

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Randolph, James; Bao, Xiaoqi; Sherrit, Stewart; Ritz, Chuck; Cook, Greg

2006-01-01

A system for automated sampling of rocks, ice, and similar hard materials at and immediately below the surface of the ground is undergoing development. The system, denoted a sample preparation, acquisition, handling, and delivery (SPAHD) device, would be mounted on a robotic exploratory vehicle that would traverse the terrain of interest on the Earth or on a remote planet. The SPAHD device would probe the ground to obtain data for optimization of sampling, prepare the surface, acquire samples in the form(s) of cores and/or powdered cuttings, and deliver the samples to a selected location for analysis and/or storage.

40 CFR 91.327 - Sampling system requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., sample line section, filters, and so forth) in the heated portion of the sampling system that has a... mass and the oven temperature need be measured. (b) If water is removed by condensation, monitor the sample gas temperature or sample dew point either within the water trap or downstream. It may not exceed...

40 CFR 91.327 - Sampling system requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., sample line section, filters, and so forth) in the heated portion of the sampling system that has a... mass and the oven temperature need be measured. (b) If water is removed by condensation, monitor the sample gas temperature or sample dew point either within the water trap or downstream. It may not exceed...

40 CFR 91.327 - Sampling system requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., sample line section, filters, and so forth) in the heated portion of the sampling system that has a... mass and the oven temperature need be measured. (b) If water is removed by condensation, monitor the sample gas temperature or sample dew point either within the water trap or downstream. It may not exceed...

40 CFR 1065.245 - Sample flow meter for batch sampling.

Code of Federal Regulations, 2010 CFR

2010-07-01

... rates or total flow sampled into a batch sampling system over a test interval. You may use the... rates or total raw exhaust flow over a test interval. (b) Component requirements. We recommend that you... averaging Pitot tube, or a hot-wire anemometer. Note that your overall system for measuring sample flow must...

78 FR 63504 - Virgil C. Summer Nuclear Station, Units 2 and 3; South Carolina Electric and Gas; Changes to the...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-24

... Nuclear Station, Units 2 and 3; South Carolina Electric and Gas; Changes to the Primary Sampling System... in Fairfield County, South Carolina. The amendment requests to modify the Primary Sampling System..., Figures 2.2.1-1 ``Containment System'' and 2.3.13-1 ``Primary Sampling System,'' and Subsection 2.3.13...

Prototype sampling system for measuring workplace protection factors for gases and vapors.

PubMed

Groves, William A; Reynolds, Stephen J

2003-05-01

A prototype sampling system for measuring respirator workplace protection factors (WPFs) was developed. Methods for measuring the concentration of contaminants inside respirators have previously been described; however, these studies have typically involved continuous sampling of aerosols. Our work focuses on developing an intermittent sampling system designed to measure the concentration of gases and vapors during inspiration. This approach addresses two potential problems associated with continuous sampling: biased results due to lower contaminant concentrations and high humidity in exhaled air. The system consists of a pressure transducer circuit designed to activate a pair of personal sampling pumps during inspiration based on differential pressure inside the respirator. One pump draws air from inside the respirator while the second samples the ambient air. Solid granular adsorbent tubes are used to trap the contaminants, making the approach applicable to a large number of gases and vapors. Laboratory testing was performed using a respirator mounted on a headform connected to a breathing machine producing a sinusoidal flow pattern with an average flow rate of 20 L/min and a period of 3 seconds. The sampling system was adjusted to activate the pumps when the pressure inside the respirator was less than -0.1 inch H(2)O. Quantitative fit-tests using human subjects were conducted to evaluate the effect of the sampling system on respirator performance. A total of 299 fit-tests were completed for two different types of respirators (half- and full-facepiece) from two different manufacturers (MSA and North). Statistical tests showed no significant differences between mean fit factors for respirators equipped with the sampling system versus unmodified respirators. Field testing of the prototype sampling system was performed in livestock production facilities and estimates of WPFs for ammonia were obtained. Results demonstrate the feasibility of this approach and will be used in developing improved instrumentation for measuring WPFs.

Apparatus for chemical amplification based on fluid partitioning in an immiscible liquid

DOEpatents

Anderson, Brian L [Lodi, CA; Colston, Bill W [San Ramon, CA; Elkin, Christopher J [San Ramon, CA

2012-05-08

A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

Method for chemical amplification based on fluid partitioning in an immiscible liquid

DOEpatents

Anderson, Brian L.; Colston, Bill W.; Elkin, Christopher J.

2015-06-02

A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

Method for chemical amplification based on fluid partitioning in an immiscible liquid

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

Anderson, Brian L.; Colston, Bill W.; Elkin, Christopher J.

A system for nucleic acid amplification of a sample comprises partitioning the sample into partitioned sections and performing PCR on the partitioned sections of the sample. Another embodiment of the invention provides a system for nucleic acid amplification and detection of a sample comprising partitioning the sample into partitioned sections, performing PCR on the partitioned sections of the sample, and detecting and analyzing the partitioned sections of the sample.

Automated mass spectrometer analysis system

NASA Technical Reports Server (NTRS)

Giffin, Charles E. (Inventor); Kuppermann, Aron (Inventor); Dreyer, William J. (Inventor); Boettger, Heinz G. (Inventor)

1982-01-01

An automated mass spectrometer analysis system is disclosed, in which samples are automatically processed in a sample processor and converted into volatilizable samples, or their characteristic volatilizable derivatives. Each volatilizable sample is sequentially volatilized and analyzed in a double focusing mass spectrometer, whose output is in the form of separate ion beams all of which are simultaneously focused in a focal plane. Each ion beam is indicative of a different sample component or different fragments of one or more sample components and the beam intensity is related to the relative abundance of the sample component. The system includes an electro-optical ion detector which automatically and simultaneously converts the ion beams, first into electron beams which in turn produce a related image which is transferred to the target of a vilicon unit. The latter converts the images into electrical signals which are supplied to a data processor, whose output is a list of the components of the analyzed sample and their abundances. The system is under the control of a master control unit, which in addition to monitoring and controlling various power sources, controls the automatic operation of the system under expected and some unexpected conditions and further protects various critical parts of the system from damage due to particularly abnormal conditions.

Automated mass spectrometer analysis system

NASA Technical Reports Server (NTRS)

Boettger, Heinz G. (Inventor); Giffin, Charles E. (Inventor); Dreyer, William J. (Inventor); Kuppermann, Aron (Inventor)

1978-01-01

An automated mass spectrometer analysis system is disclosed, in which samples are automatically processed in a sample processor and converted into volatilizable samples, or their characteristic volatilizable derivatives. Each volatizable sample is sequentially volatilized and analyzed in a double focusing mass spectrometer, whose output is in the form of separate ion beams all of which are simultaneously focused in a focal plane. Each ion beam is indicative of a different sample component or different fragments of one or more sample components and the beam intensity is related to the relative abundance of the sample component. The system includes an electro-optical ion detector which automatically and simultaneously converts the ion beams, first into electron beams which in turn produce a related image which is transferred to the target of a vidicon unit. The latter converts the images into electrical signals which are supplied to a data processor, whose output is a list of the components of the analyzed sample and their abundances. The system is under the control of a master control unit, which in addition to monitoring and controlling various power sources, controls the automatic operation of the system under expected and some unexpected conditions and further protects various critical parts of the system from damage due to particularly abnormal conditions.

Recommendations for level-determined sampling in wells

NASA Astrophysics Data System (ADS)

Lerner, David N.; Teutsch, Georg

1995-10-01

Level-determined samples of groundwater are increasingly important for hydrogeological studies. The techniques for collecting them range from the use of purpose drilled wells, sometimes with sophisticated dedicated multi-level samplers in them, to a variety of methods used in open wells. Open, often existing, wells are frequently used on cost grounds, but there are risks of obtaining poor and unrepresentative samples. Alternative approaches to level-determined sampling incorporate seven concepts: depth sampling; packer systems; individual wells; dedicated multi-level systems; separation pumping; baffle systems; multi-port sock samplers. These are outlined and evaluated in terms of the environment to be sampled, and the features and performance of the methods. Recommendations are offered to match methods to sampling problems.

47 CFR 73.151 - Field strength measurements to establish performance of directional antennas.

Code of Federal Regulations, 2010 CFR

2010-10-01

... verified either by field strength measurement or by computer modeling and sampling system verification. (a... specifically identified by the Commission. (c) Computer modeling and sample system verification of modeled... performance verified by computer modeling and sample system verification. (1) A matrix of impedance...

A THz Tomography System for Arbitrarily Shaped Samples

NASA Astrophysics Data System (ADS)

Stübling, E.; Bauckhage, Y.; Jelli, E.; Fischer, B.; Globisch, B.; Schell, M.; Heinrich, A.; Balzer, J. C.; Koch, M.

2017-10-01

We combine a THz time-domain spectroscopy system with a robotic arm. With this scheme, the THz emitter and receiver can be positioned perpendicular and at defined distance to the sample surface. Our system allows the acquisition of reflection THz tomographic images of samples with an arbitrarily shaped surface.

Urine sampling and collection system

NASA Technical Reports Server (NTRS)

Fogal, G. L.; Mangialardi, J. K.; Reinhardt, C. G.

1971-01-01

This specification defines the performance and design requirements for the urine sampling and collection system engineering model and establishes requirements for its design, development, and test. The model shall provide conceptual verification of a system applicable to manned space flight which will automatically provide for collection, volume sensing, and sampling of urine.

Automated biowaste sampling system improved feces collection, mass measurement and sampling. [by use of a breadboard model

NASA Technical Reports Server (NTRS)

Fogal, G. L.; Mangialardi, J. K.; Young, R.

1974-01-01

The capability of the basic automated Biowaste Sampling System (ABSS) hardware was extended and improved through the design, fabrication and test of breadboard hardware. A preliminary system design effort established the feasibility of integrating the breadboard concepts into the ABSS.

Subsurface Sample Acquisition and Transfer Systems (SSATS)

NASA Astrophysics Data System (ADS)

Rafeek, S.; Gorevan, S. P.; Kong, K. Y.

2001-01-01

In the exploration of planets and small bodies, scientists will need the services of a deep drilling and material handling system to not only obtain the samples necessary for analyses but also to precisely transfer and deposit those samples in in-situ instruments on board a landed craft or rover. The technology for such a deep sampling system as the SSATS is currently been developed by Honeybee Robotics through a PIDDP effort. The SSATS has its foundation in a one-meter prototype (SATM) drill that was developed under the New Millenium Program for ST4/Champollion. Additionally the SSATS includes relevant coring technology form a coring drill (Athena Mini-Corer) developed for the Mars Sample Return Mission. These highly developed technologies along with the current PIDDP effort, is combined to produce a sampling system that can acquire and transfer samples from various depths. Additional information is contained in the original extended abstract.

Exponential synchronization of neural networks with discrete and distributed delays under time-varying sampling.

PubMed

Wu, Zheng-Guang; Shi, Peng; Su, Hongye; Chu, Jian

2012-09-01

This paper investigates the problem of master-slave synchronization for neural networks with discrete and distributed delays under variable sampling with a known upper bound on the sampling intervals. An improved method is proposed, which captures the characteristic of sampled-data systems. Some delay-dependent criteria are derived to ensure the exponential stability of the error systems, and thus the master systems synchronize with the slave systems. The desired sampled-data controller can be achieved by solving a set of linear matrix inequalitys, which depend upon the maximum sampling interval and the decay rate. The obtained conditions not only have less conservatism but also have less decision variables than existing results. Simulation results are given to show the effectiveness and benefits of the proposed methods.

Producing samples for the organization of proficiency tests. Study of the homogeneity of replicas produced from two atmosphere generation systems.

PubMed

Freville, Laurence; Moulut, Jean-Claude; Grzebyk, Michel; Kauffer, Edmond

2010-08-01

This article describes two atmosphere generation systems used for the production of replicas. The first, the Sputnic system, is based on the Sputnic air sampler developed by the National Institute of Occupational Health in Oslo (Norway). It is used to generate asbestos fibres or silica particles and allows the simultaneous production, by means of sampling on filters, of up to 114 replicas. The second is a multipurpose system that allows dust sampling on foams used with the CIP 10-R device. Twenty samples can be taken simultaneously. In total, 120 series of samples allowed characterization of the variability of the two generation systems used for the production of replicas loaded with asbestos fibres or silica dust. The coefficients of variation characterizing the dispersion of the filter loading in the Sputnic system are <10% for high densities asbestos fibre or silica dust samples. The coefficient of dispersion is on average higher when the asbestos fibre density is lower. The differences observed between the measurements taken on the different crowns of the Sputnic system are low and <2%. The results obtained with the multipurpose system show that replica dispersion is on average equal to 4%, which will allow proposal in the near future of a proficiency test dedicated to the quantitative analysis of crystalline silica on foams sampled with the CIP 10-R device.

Multi-Mission System Analysis for Planetary Entry (M-SAPE) Version 1

NASA Technical Reports Server (NTRS)

Samareh, Jamshid; Glaab, Louis; Winski, Richard G.; Maddock, Robert W.; Emmett, Anjie L.; Munk, Michelle M.; Agrawal, Parul; Sepka, Steve; Aliaga, Jose; Zarchi, Kerry;

Novel Integration of a 6t Cryogen-Free Magneto-Optical System with a Variable Temperature Sample Using a Single Cryocooler

NASA Astrophysics Data System (ADS)

Berryhill, A. B.; Coffey, D. M.; McGhee, R. W.; Burkhardt, E. E.

2008-03-01

Cryomagnetics' new "C-Mag Optical" Magneto-Optic Property Measurement System is a versatile materials and device characterization system that allows the researcher to simultaneously control the applied magnetic field and temperature of a sample while studying its electrical and optic properties. The system integrates a totally liquid cryogen-free 6T superconducting split-pair magnet with a variable temperature sample space, both cooled using a single 4.2K pulse tube refrigerator. To avoid warming the magnet when operating a sample at elevated temperatures, a novel heat switch was developed. The heat switch allows the sample temperature to be varied from 10K to 300K while maintaining the magnet at 4.2K or below. In this paper, the design and performance of the overall magnet system and the heat switch will be presented. New concepts for the next generation system will also be discussed.

Air Sample Conditioner Helps the Waste Treatment Plant Meet Emissions Standards

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

Glissmeyer, John A.; Flaherty, Julia E.; Pekour, Mikhail S.

2014-12-02

The air in three of the Hanford Site Waste Treatment and Immobilization Plant (WTP) melter off-gas discharge stacks will be hot and humid after passing through the train of emission abatement equipment. The off-gas temperature and humidity levels will be incompatible with the airborne emissions monitoring equipment required for this type of stack. To facilitate sampling from these facilities, an air sample conditioner system will be installed to introduce cool, dry air into the sample stream to reduce the temperature and dew point. This will avoid thermal damage to the instrumentation and problematic condensation. The complete sample transport system mustmore » also deliver at least 50% of the particles in the sample airstream to the sample collection and on-line analysis equipment. The primary components of the sample conditioning system were tested in a laboratory setting. The sample conditioner itself is based on a commercially-available porous tube filter design. It consists of a porous sintered metal tube inside a coaxial metal jacket. The hot gas sample stream passes axially through the porous tube, and the dry, cool air is injected into the jacket and through the porous wall of the inner tube, creating an effective sample diluter. The dilution and sample air mix along the entire length of the porous tube, thereby simultaneously reducing the dew point and temperature of the mixed sample stream. Furthermore, because the dilution air enters through the porous tube wall, the sample stream does not come in contact with the porous wall and particle deposition is reduced in this part of the sampling system. Tests were performed with an environmental chamber to supply air with the temperature and humidity needed to simulate the off-gas conditions. Air from the chamber was passed through the conditioning system to test its ability to reduce the temperature and dew point of the sample stream. To measure particle deposition, oil droplets in the range of 9 to 11 micrometer aerodynamic diameter were injected into the environmental chamber and drawn through the conditioning system, which included a filter to capture droplets that passed through the conditioner. The droplets were tagged with a fluorescent dye which allowed quantification of droplet deposition on each component of the system. The tests demonstrated the required reductions in temperature and moisture, with no condensation forming when heat tracing was added on the upstream end of the sample conditioner. Additionally, tests indicated that the system, operating at several flow rates and in both vertical and horizontal orientations, delivers nearly all of the sampled particles for analysis. Typical aerosol penetration values were between 98 and 99%. PNNL, Bechtel National Inc., and the instrument vendor are working to implement the sample conditioner into the air monitoring systems used for the melter off-gas exhaust streams. Similar technology may be useful for processes in other facilities with air exhaust streams with elevated temperature and/or humidity.« less

KDB-1 LOW-LEVEL AIRCRAFT SAMPLING SYSTEM

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

Plagge, H.J.

1961-03-01

Use of KDB-1 drone aircraft appears feasible for the sampling of atomic debris at altitudes from 1000 to 40,000 feet. Further development would be necessary for precision control below 1000 feet. Further development and testing remains to be done on the sampling devices before the system can become operational. This system would be approximately one-seventh as expensive as present systems using manned aircraft. (auth)

Systems and methods for laser assisted sample transfer to solution for chemical analysis

DOEpatents

Van Berkel, Gary J.; Kertesz, Vilmos; Ovchinnikova, Olga S.

2014-06-03

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

Systems and methods for laser assisted sample transfer to solution for chemical analysis

DOEpatents

Van Berkel, Gary J.; Kertesz, Vilmos; Ovchinnikova, Olga S.

2015-09-29

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

Systems and methods for laser assisted sample transfer to solution for chemical analysis

DOEpatents

Van Berkel, Gary J; Kertesz, Vilmos; Ovchinnikova, Olga S

2013-08-27

Systems and methods are described for laser ablation of an analyte from a specimen and capturing of the analyte in a dispensed solvent to form a testing solution. A solvent dispensing and extraction system can form a liquid microjunction with the specimen. The solvent dispensing and extraction system can include a surface sampling probe. The laser beam can be directed through the surface sampling probe. The surface sampling probe can also serve as an atomic force microscopy probe. The surface sampling probe can form a seal with the specimen. The testing solution including the analyte can then be analyzed using an analytical instrument or undergo further processing.

Molecular dynamics coupled with a virtual system for effective conformational sampling.

PubMed

Hayami, Tomonori; Kasahara, Kota; Nakamura, Haruki; Higo, Junichi

2018-07-15

An enhanced conformational sampling method is proposed: virtual-system coupled canonical molecular dynamics (VcMD). Although VcMD enhances sampling along a reaction coordinate, this method is free from estimation of a canonical distribution function along the reaction coordinate. This method introduces a virtual system that does not necessarily obey a physical law. To enhance sampling the virtual system couples with a molecular system to be studied. Resultant snapshots produce a canonical ensemble. This method was applied to a system consisting of two short peptides in an explicit solvent. Conventional molecular dynamics simulation, which is ten times longer than VcMD, was performed along with adaptive umbrella sampling. Free-energy landscapes computed from the three simulations mutually converged well. The VcMD provided quicker association/dissociation motions of peptides than the conventional molecular dynamics did. The VcMD method is applicable to various complicated systems because of its methodological simplicity. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Onco-STS: a web-based laboratory information management system for sample and analysis tracking in oncogenomic experiments.

PubMed

Gavrielides, Mike; Furney, Simon J; Yates, Tim; Miller, Crispin J; Marais, Richard

2014-01-01

Whole genomes, whole exomes and transcriptomes of tumour samples are sequenced routinely to identify the drivers of cancer. The systematic sequencing and analysis of tumour samples, as well other oncogenomic experiments, necessitates the tracking of relevant sample information throughout the investigative process. These meta-data of the sequencing and analysis procedures include information about the samples and projects as well as the sequencing centres, platforms, data locations, results locations, alignments, analysis specifications and further information relevant to the experiments. The current work presents a sample tracking system for oncogenomic studies (Onco-STS) to store these data and make them easily accessible to the researchers who work with the samples. The system is a web application, which includes a database and a front-end web page that allows the remote access, submission and updating of the sample data in the database. The web application development programming framework Grails was used for the development and implementation of the system. The resulting Onco-STS solution is efficient, secure and easy to use and is intended to replace the manual data handling of text records. Onco-STS allows simultaneous remote access to the system making collaboration among researchers more effective. The system stores both information on the samples in oncogenomic studies and details of the analyses conducted on the resulting data. Onco-STS is based on open-source software, is easy to develop and can be modified according to a research group's needs. Hence it is suitable for laboratories that do not require a commercial system.

A novel atmospheric tritium sampling system

NASA Astrophysics Data System (ADS)

Qin, Lailai; Xia, Zhenghai; Gu, Shaozhong; Zhang, Dongxun; Bao, Guangliang; Han, Xingbo; Ma, Yuhua; Deng, Ke; Liu, Jiayu; Zhang, Qin; Ma, Zhaowei; Yang, Guo; Liu, Wei; Liu, Guimin

2018-06-01

The health hazard of tritium is related to its chemical form. Sampling different chemical forms of tritium simultaneously becomes significant. Here a novel atmospheric tritium sampling system (TS-212) was developed to collect the tritiated water (HTO), tritiated hydrogen (HT) and tritiated methane (CH3T) simultaneously. It consisted of an air inlet system, three parallel connected sampling channels, a hydrogen supply module, a methane supply module and a remote control system. It worked at air flow rate of 1 L/min to 5 L/min, with temperature of catalyst furnace at 200 °C for HT sampling and 400 °C for CH3T sampling. Conversion rates of both HT and CH3T to HTO were larger than 99%. The collecting efficiency of the two-stage trap sets for HTO was larger than 96% in 12 h working-time without being blocked. Therefore, the collected efficiencies of TS-212 are larger than 95% for tritium with different chemical forms in environment. Besides, the remote control system made sampling more intelligent, reducing the operator's work intensity. Based on the performance parameters described above, the TS-212 can be used to sample atmospheric tritium in different chemical forms.

Hot flue-gas spiking and recovery study for tetrachlorodibenzodioxins (TCDD) using Modified Method 5 and SASS (Source Assessment Sampling System) sampling with a simulated incinerator. Final report, May 1981-February 1982

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

Cooke, M.; DeRoos, F.; Rising, B.

1984-10-01

The report gives results of an evaluation of the sampling and analysis of ultratrace levels of dibenzodioxins using EPA's recommended source sampling procedures (Modified Method 5 (MM5) train and the Source Assessment Sampling System--SASS). A gas-fired combustion system was used to simulate incineration flue gas, and a precision liquid injection system was designed for the program. The precision liquid injector was used to administer dilute solutions of 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD) directly into a hot--260C (500F)--flue gas stream. Injections occurred continuously during the sampling episode so that very low gas-phase concentrations of 1,2,3,4-TCDD were continuously mixed with the flue gases. Recoveries weremore » measured for eight burn experiments. For all but one, the recoveries could be considered quantitative, demonstrating efficient collection by the EPA sampling systems. In one study, the components and connecting lines from a sampling device were analyzed separately to show where the 1,2,3,4-TCDD deposited in the train.« less

A multi-probe thermophoretic soot sampling system for high-pressure diffusion flames

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

Vargas, Alex M.; Gülder, Ömer L.

Optical diagnostics and physical probing of the soot processes in high pressure combustion pose challenges that are not faced in atmospheric flames. One of the preferred methods of studying soot in atmospheric flames is in situ thermophoretic sampling followed by transmission electron microscopy imaging and analysis for soot sizing and morphology. The application of this method of sampling to high pressures has been held back by various operational and mechanical problems. In this work, we describe a rotating disk multi-probe thermophoretic soot sampling system, driven by a microstepping stepper motor, fitted into a high-pressure chamber capable of producing sooting laminarmore » diffusion flames up to 100 atm. Innovative aspects of the sampling system design include an easy and precise control of the sampling time down to 2.6 ms, avoidance of the drawbacks of the pneumatic drivers used in conventional thermophoretic sampling systems, and the capability to collect ten consecutive samples in a single experimental run. Proof of principle experiments were performed using this system in a laminar diffusion flame of methane, and primary soot diameter distributions at various pressures up to 10 atm were determined. High-speed images of the flame during thermophoretic sampling were recorded to assess the influence of probe intrusion on the flow field of the flame.« less

40 CFR 141.703 - Sampling locations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Sampling locations. 141.703 Section... Monitoring Requirements § 141.703 Sampling locations. (a) Systems required to conduct source water monitoring... a sampling tap is available where the sources are combined prior to treatment, systems must collect...

Customized sampling plans : a guide to alternative sampling techniques for National Transit Database reporting

DOT National Transportation Integrated Search

2004-05-01

For estimating the system total unlinked passenger trips and passenger miles of a fixed-route bus system for the National Transit Database (NTD), the FTA approved sampling plans may either over-sample or do not yield FTAs required confidence and p...

40 CFR 1066.135 - Linearity verification.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CVS, double-dilution, and partial-flow systems. (3) PM sample. (4) Chiller sample, for gaseous sampling systems that use thermal chillers to dry samples, and that use chiller temperature to calculate dewpoint at the chiller outlet. For testing, if you choose to use the high alarm temperature setpoint for...

National automotive sampling system crashworthiness data system 1994-1996

DOT National Transportation Integrated Search

1999-10-01

This report focuses attention on occupants of those passenger vehicles that were towed from : the crash scene. NHTSA's National Automotive Sampling System (NASS)/ Crashworthiness : Data System (CDS) collects detailed information on towed passenger ve...

Development of a split-flow system for high precision variable sample introduction in supercritical fluid chromatography.

PubMed

Sakai, Miho; Hayakawa, Yoshihiro; Funada, Yasuhiro; Ando, Takashi; Fukusaki, Eiichiro; Bamba, Takeshi

2017-09-15

In this study, we propose a novel variable sample injection system based on full-loop injection, named the split-flow sample introduction system, for application in supercritical fluid chromatography (SFC). In this system, the mobile phase is split by the differential pressure between two back pressure regulators (BPRs) after full-loop injection suitable for SFC, and this differential pressure determines the introduction rate. Nine compounds with a wide range of characteristics were introduced with high reproducibility and universality, confirming that a robust variable sample injection system was achieved. We also investigated the control factors of our proposed system. Sample introduction was controlled by the ratio between the column-side pressure drops in splitless and split flow, ΔP columnsideinsplitless and ΔP columnsideinsplit , respectively, where ΔP columnsideinsplitless is related to the mobile phase flow rate and composition and the column resistance. When all other conditions are kept constant, increasing the make-up flow induces an additional pressure drop on the column side of the system, which leads to a reduced column-side flow rate, and hence decreased the amount of sample injected, even when the net pressure drop on the column side remains the same. Thus, sample introduction could be highly controlled at low sample introduction rate, regardless of the introduction conditions. This feature is advantageous because, as a control factor, the solvent in the make-up pump is independent of the column-side pressure drop. Copyright © 2017. Published by Elsevier B.V.

40 CFR 86.209-94 - Exhaust gas sampling system; gasoline-fueled vehicles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Exhaust gas sampling system; gasoline... Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty... sampling system; gasoline-fueled vehicles. The provisions of § 86.109-90 apply to this subpart. ...

40 CFR 86.209-94 - Exhaust gas sampling system; gasoline-fueled vehicles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Exhaust gas sampling system; gasoline... Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty... sampling system; gasoline-fueled vehicles. The provisions of § 86.109-90 apply to this subpart. ...

40 CFR 86.209-94 - Exhaust gas sampling system; gasoline-fueled vehicles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Exhaust gas sampling system; gasoline... Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty... sampling system; gasoline-fueled vehicles. The provisions of § 86.109-90 apply to this subpart. ...