scholarly journals Miami Natural Radiocarbon Measurements I

Radiocarbon ◽  
1962 ◽  
Vol 4 ◽  
pp. 51-56 ◽  
Author(s):  
H. Göte Östlund ◽  
Albert L. Bowman ◽  
Gene A. Rusnak
Keyword(s):  
Geographic Location ◽  
Cosmic Ray ◽  
Concrete Block ◽  
Total Sample ◽  
Sample Volume ◽  
Active Volume ◽  
Coral Rock ◽  
Counting Tube ◽  
One Year ◽  
Total Sample Volume

The construction of the dating apparatus started in the summer of 1960 and was completed one year later. The laboratory is located on the bottom floor of a three-story concrete-block building which has two thin concrete floors on concrete beams above the shield. The building is underlain by carbonate mud and coral rock. The geographic location is 25° 43.9′ N Lat, 80° 09.8′ W Long and only a few feet above sealevel. We use a proportional-counting tube with an active volume of 1 L, and a total sample volume of 1.30 L, filled with purified CO2to a pressure of 225 cm Hg (3 atm) at 25°C. The tube is made of copper with brass ends and quartz insulators. The shielding consists of 20 cm of iron, 10 cm of paraffin with boric acid, 2.5 cm of selected lead (Östlund, 1961), and cosmic ray guard counters. The room is air-conditioned but no additional precautions have been taken to exclude outdoor dust.

SAMPLE INJECTION IN PROGRAMMED TEMPERATURE GAS CHROMATOGRAPHY AND ITS SIGNIFICANCE FOR TRACE ANALYSIS

1965 ◽  
Vol 43 (5) ◽  
pp. 1560-1568 ◽  
Author(s):  
L. W. Hollingshead ◽  
H. W. Habgood ◽  
W. E. Harris
Keyword(s):  
Trace Analysis ◽  
Initial Temperature ◽  
Retention Volume ◽  
Total Sample ◽  
Sample Volume ◽  
Plate Height ◽  
Peak Broadening ◽  
Increased Sensitivity ◽  
Experimental Values ◽  
Total Sample Volume

The measurement of apparent plate heights resulting from various values of the total sample volume has been carried out for C5 to C8n-alkanes on Apiezon L under both isothermal and p.t.g.c. conditions. Plug injection of samples was achieved through the use of a syringe plunger driven at constant speed by a motor. The time for injection of gas samples ranged from 1 to 300 s. All of the results, both isothermal and p.t.g.c, could be correlated to the same plot of Happ/Hc against √nΔVs/VT0 where Happ is the observed plate height, Hc the limiting plate height at low sample volumes, n the true plate number, ΔVs the sample volume, and VT0 the isothermal retention volume at the initial temperature. The experimental values lie somewhat above the theoretical curve calculated by van Deemter et al. It is confirmed that sample volumes less than [Formula: see text] give negligible excess peak broadening. Applying these concepts to trace analysis, very large samples may be used in p.t.g.c. under such initial temperature conditions that the major component is only weakly retained, while traces of heavier components are concentrated into narrow bands and eluted as sharp peaks with the increased sensitivity provided by the large sample. As an example, chromatograms are presented for the p.t.g.c. analysis of natural gas on deactivated alumina, using sample volumes ranging from 2 to 500 ml.

On-line liquid-chromatographic analysis for drugs in serum with the Technicon "FAST-LC" system: performance data for theophylline and for four commonly used anticonvulsants and their metabolites.

1980 ◽  
Vol 26 (7) ◽  
pp. 871-880 ◽  
Author(s):  
J W Dolan ◽  
S van der Wal ◽  
S J Bannister ◽  
L R Snyder
Keyword(s):  
High Performance ◽  
Total Sample ◽  
Sample Volume ◽  
Active Metabolites ◽  
Serum Samples ◽  
New Instrument ◽  
On Line ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic ◽  
Total Sample Volume

Abstract We describe a new instrument for use in assay of therpeutic drugs in serum by "high-performance" liquid chromatography, the "FAST-LC" system (Technicon). Serum samples are aspirated directly into the unit, extracted with solvent, and the evaporated and redissolved extract is injected onto a chromatographic column. We illustrate the performance of the system by assays in serum for theophylline and four anticonvulsants (primidone, phenobarbital, phenytoin, and carbamazepine) plus two of their active metabolites (phenylethylmalonamide and carbamazepine epoxide). For theophylline, final chromatograms are monitored at 270 nm, at analysis rates of 10/h. Concentration and absorbance are linearly related from 0 to 130 mg of theophylline per liter. For the anticonvulsants, chromatograms are monitored at 200 nm, at analysis rates of 7.5/h. The six individual determinations are each linear beyond the therapeutic range. For both drug panels, day-to-day CV's were 4 to 6%. Results correlate well with those by enzyme immunoassay. A total sample volume of 150 microL is required.

New techniques and tools for clinical chemistry.

1983 ◽  
Vol 29 (9) ◽  
pp. 1659-1664 ◽  
Author(s):  
G M Hieftje
Keyword(s):  
Ion Chromatography ◽  
Clinical Chemistry ◽  
Absorption Spectrometry ◽  
Total Sample ◽  
Sample Volume ◽  
Beam Optics ◽  
New Techniques ◽  
Double Beam ◽  
Total Sample Volume ◽  
Potential Use

Abstract In this paper are described and evaluated several new tools of potential use in clinical chemistry. The first, intended to minimize required sample volumes, is a device with which a total sample volume of 1 microL can be dispensed in the form of 1000 identical aliquots. Any number of such nanoliter aliquots can be taken if larger samples are needed. The second new tool is one for detecting anions or cations separated by ion chromatography. Unlike conventional conductometric detectors used in ion chromatography, the new system offers potential sensitivities in the sub-microgram per liter range and useful operating ranges up to 100 mg/L. The third tool is a scheme for background correction in atomic absorption spectrometry; the new technique requires no special auxiliary sources or double-beam optics. Finally, fluorescence time-decay curves and fluorescence lifetimes are shown to be able to overcome the effects of diffusional quenching and scattering resulting from turbidity of solutions in clinical fluorometry.

Liquid-chromatographic analysis for common tricyclic antidepressant drugs and their metabolites in serum or plasma with the technicon "FAST-LC" system.

1981 ◽  
Vol 27 (6) ◽  
pp. 849-855 ◽  
Author(s):  
S J Bannister ◽  
S van der Wal ◽  
J W Dolan ◽  
L R Snyder
Keyword(s):  
High Performance ◽  
Antidepressant Drugs ◽  
Total Sample ◽  
Sample Volume ◽  
Tricyclic Antidepressant ◽  
Tricyclic Antidepressant Drugs ◽  
Liquid Chromatographic Analysis ◽  
Double Extraction ◽  
Liquid Chromatographic ◽  
Total Sample Volume

Abstract We describe a single procedure for assay of seven tricyclic antidepressant drugs and metabolites in serum or plasma: protriptyline, nortriptyline, amitriptyline, desmethyldoxepin, doxepin, desipramine, and imipramine. With the Technicon "FAST-LC" system, samples are aspirated directly into the unit and pretreated via double extraction; the concentration of each drug is then determined by "high-performance" liquid chromatography. Final chromatograms are monitored at 205 nm, at analysis rates of 7.5 samples/h. Concentration and absorbance are linearly related for each drug from 0 to 1400 micrograms/L. Day-to-day CVs averaged 5 to 6% for each drug, and there is good correlation of FAST-LC values with those obtained by gas-chromatographic methods. Total sample volume is 750 microliters.

Cerebrospinal fluid sampling from guineapigs: Sample volume-related changes in protein concentration in control animals and animals in the relapsing phase of chronic relapsing experimental allergic encephalomyelitis

1984 ◽  
Vol 18 (1) ◽  
pp. 36-39 ◽  
Author(s):  
A. J. Suckling ◽  
H. Reiber
Keyword(s):  
Cerebrospinal Fluid ◽  
Experimental Allergic Encephalomyelitis ◽  
Protein Concentration ◽  
Total Sample ◽  
Sample Volume ◽  
Albumin Concentration ◽  
Allergic Encephalomyelitis ◽  
Total Sample Volume ◽  
Experimental Allergic

Cerebrospinal fluid (CSF) was removed from guineapigs by puncture of the cisterna magna and the total sample volume of 200-360 µl divided into 40 µl aliquots. After determination of albumin and IgG in these CSF aliquots it was found that successive samples gave different results. In general, up to 100 µl CSF could be removed before the protein concentration began to increase. In animals with chronic relapsing experimental allergic encephalomyelitis (CR-EAE) the rise in albumin concentration was accompanied by a corresponding fall in the number of white cells in later samples.

On-line liquid-chromatographic analysis for drugs in serum with the Technicon "FAST-LC" system: performance data for theophylline and for four commonly used anticonvulsants and their metabolites.

1980 ◽  
Vol 26 (7) ◽  
pp. 871-880
Author(s):  
J W Dolan ◽  
S van der Wal ◽  
S J Bannister ◽  
L R Snyder
Keyword(s):  
High Performance ◽  
Total Sample ◽  
Sample Volume ◽  
Active Metabolites ◽  
Serum Samples ◽  
New Instrument ◽  
On Line ◽  
Liquid Chromatographic Analysis ◽  
Liquid Chromatographic ◽  
Total Sample Volume

Abstract We describe a new instrument for use in assay of therpeutic drugs in serum by "high-performance" liquid chromatography, the "FAST-LC" system (Technicon). Serum samples are aspirated directly into the unit, extracted with solvent, and the evaporated and redissolved extract is injected onto a chromatographic column. We illustrate the performance of the system by assays in serum for theophylline and four anticonvulsants (primidone, phenobarbital, phenytoin, and carbamazepine) plus two of their active metabolites (phenylethylmalonamide and carbamazepine epoxide). For theophylline, final chromatograms are monitored at 270 nm, at analysis rates of 10/h. Concentration and absorbance are linearly related from 0 to 130 mg of theophylline per liter. For the anticonvulsants, chromatograms are monitored at 200 nm, at analysis rates of 7.5/h. The six individual determinations are each linear beyond the therapeutic range. For both drug panels, day-to-day CV's were 4 to 6%. Results correlate well with those by enzyme immunoassay. A total sample volume of 150 microL is required.

scholarly journals Sensitivity of direct detection experiments to neutrino magnetic dipole moments

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
D. Aristizabal Sierra ◽  
R. Branada ◽  
O. G. Miranda ◽  
G. Sanchez Garcia
Keyword(s):  
Dark Matter ◽  
Magnetic Dipole ◽  
Direct Detection ◽  
Dipole Moments ◽  
Nuclear Recoil ◽  
Active Volume ◽  
Electron Recoil ◽  
Flux Measurements ◽  
Neutrino Fluxes ◽  
One Year

Abstract With large active volume sizes dark matter direct detection experiments are sensitive to solar neutrino fluxes. Nuclear recoil signals are induced by 8B neutrinos, while electron recoils are mainly generated by the pp flux. Measurements of both processes offer an opportunity to test neutrino properties at low thresholds with fairly low backgrounds. In this paper we study the sensitivity of these experiments to neutrino magnetic dipole moments assuming 1, 10 and 40 tonne active volumes (representative of XENON1T, XENONnT and DARWIN), 0.3 keV and 1 keV thresholds. We show that with nuclear recoil measurements alone a 40 tonne detector could be as competitive as Borexino, TEXONO and GEMMA, with sensitivities of order 8.0 × 10−11μB at the 90% CL after one year of data taking. Electron recoil measurements will increase sensitivities way below these values allowing to test regions not excluded by astrophysical arguments. Using electron recoil data and depending on performance, the same detector will be able to explore values down to 4.0 × 10−12μB at the 90% CL in one year of data taking. By assuming a 200-tonne liquid xenon detector operating during 10 years, we conclude that sensitivities in this type of detectors will be of order 10−12μB. Reducing statistical uncertainties may enable improving sensitivities below these values.

EARLY RESULTS FROM THE HIGH-RESOLUTION FLY's EYE

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1019-1021
Author(s):  
JOHN BELZ
Keyword(s):  
High Resolution ◽  
Cosmic Ray ◽  
Energy Spectra ◽  
Fluorescence Technique ◽  
Early Results ◽  
One Year ◽  
High Resolution Fly's Eye

The High-Resolution Fly's Eye cosmic ray observatory has been operating in monocular (stereo) mode for about three years (one year), during which time we have observed extensive airshowers with an integrated aperture of ~ 1500 km2-sr-yr (~ 400 km-sr-yr) at 5×1019 eV. We describe the HiRes experiment and the nitrogen fluorescence technique, and present data taken in both monocular and stereo modes including preliminary energy spectra.

Intensive Fostering: An Independent Evaluation of MTFC in an English Setting

2012 ◽  
Vol 36 (1) ◽  
pp. 13-26 ◽  
Author(s):  
Nina Biehal ◽  
Sarah Ellison ◽  
Ian Sinclair
Keyword(s):  
Young People ◽  
Total Sample ◽  
High Risk Group ◽  
Eligibility Criteria ◽  
Independent Evaluation ◽  
Quasi Experimental ◽  
One Year ◽  
Stage 1 ◽  
Official Data

Nina Biehal, Sarah Ellison and Ian Sinclair present the results of an independent evaluation of the Multidimensional Treatment Foster Care (MTFC) programme for young offenders in England, where it is known as Intensive Fostering (IF). A quasi-experimental, mixed-methods study was carried out at the three pilot sites, with a total sample of 47 at follow-up. Young people sentenced to IF were compared to a similar group, matched on the eligibility criteria for IF, the majority of whom were sentenced to custody. The groups were well matched in terms of their characteristics and criminal histories. Official data on reconviction were collected at baseline and one year after entry to the IF placement or release from custody (Stage 1), and further data on programme completion and secondary outcomes were collected via interviews with young people and parents, and questionnaires to professionals at baseline and follow-up. Official data on reconviction were also collected one year after exit from the IF placements (Stage 2). At Stage 1 the IF group were less likely to be reconvicted, had committed fewer and less-serious recorded offences, on average, and took longer to commit their first recorded offence. At this point the IF group were more likely to be living with their families and less likely to be in custody than the comparison group. However, by Stage 2 no significant differences in patterns of reconviction remained. IF successfully contained a high-risk group in the community, but the effects of the intervention diminished once they left their foster placements. Environmental effects on entry to and exit from the IF placements may help to explain the results at both stages.

scholarly journals Reduction of the Error Multiplier by a Long-Term Analysis of the Characteristic Behaviors of Proportional Counters

Radiocarbon ◽  
1997 ◽  
Vol 40 (1) ◽  
pp. 143-149 ◽  
Author(s):  
Ingrid U. Olsson
Keyword(s):  
Cosmic Ray ◽  
Barometric Pressure ◽  
Careful Analysis ◽  
Soft Component ◽  
Proportional Counters ◽  
Standard Values ◽  
One Year ◽  
Internal Error ◽  
Term Analysis

A significant reduction in cosmic-ray activity and backgrounds of the gas-filled proportional counters, as measured in a heavy iron shield, was observed when the Uppsala Conventional 14C Laboratory was moved in 1984. The new site was better shielded from cosmic rays because of additional concrete layers above the laboratory. A study that lasted over one year yielded a figure for the muon reduction. The backgrounds were reduced approximately to the extent expected from the soft-component contribution at the old Laboratory as judged from barometric-pressure dependence. After a few years, new electronics enforced, and enabled, the revision and improvement of the standard values for the activity and age calculations.A careful analysis of the results for the counters has increased the accuracy of the small corrections needed to yield internal error-multiplication factors mostly between 1 and 1.5 for the background for short periods of up to 12 months, and <1.1 for the oxalic acid samples combined for the last few years of measurements in the laboratory. Similar results were obtained for two counters.

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