A fully automated system for the extraction of in situ cosmogenic carbon-14 in the Tulane University cosmogenic nuclide laboratory

Abstract. Froth flotation is a commonly used procedure for separating feldspars and micas from quartz for the preparation of quartz mineral separates to carry out cosmogenic nuclide analysis. Whilst extracting carbon from quartz we observed in situ carbon-14 (14C) concentrations which were anomalously high and in excess of theoretical geological maximum concentrations. Further etching of sample material reduced carbon yields and 14C concentrations, yet the latter remained unrealistically high. When quartz from the original whole rock sample was isolated in our laboratory, we observed even lower carbon yields and geologically plausible in situ 14C concentrations. After ruling out unlikely geological scenarios and systematic measurement issues, we decided to investigate the quartz isolation procedure as a potential source of 14C contamination. We hypothesised that laurylamine (dodecylamine), an organic compound used as part of the froth flotation procedure, elevates 14C concentrations if residual laurylamine is present. We demonstrate that laurylamine has a 14C modern carbon source and thus has the potential to influence in situ 14C measurements if present in minute but measurable quantities. Furthermore, we show that insufficient sample etching results in contaminant 14C persisting through the step heating of quartz that is subsequently collected with the in situ component released at 1100 ∘C. We demonstrate that froth flotation contaminates in situ 14C measurements. We provide guidelines for the preparation of quartz based on methods developed in our laboratory and demonstrate that all froth-flotation-derived carbon and 14C is removed when applied. We recommend that the procedures presented be used at a minimum when using froth flotation to isolate quartz for in situ 14C measurements.

Download Full-text

Isolation of quartz for cosmogenic in situ <sup>14</sup>C analysis

10.5194/gchron-2019-7 ◽

2019 ◽

Author(s):

Keir A. Nichols ◽

Brent M. Goehring

Keyword(s):

Rock Sample ◽

Froth Flotation ◽

Isolation Procedure ◽

Measurement Issues ◽

Carbon 14 ◽

Cosmogenic Nuclide ◽

Potential Source ◽

Step Heating ◽

Lower Carbon

Abstract. Froth flotation is a commonly used procedure for separating feldspars and micas from quartz for the preparation of quartz mineral separates to carry out cosmogenic nuclide analysis. Whilst extracting carbon from quartz we observed in situ carbon-14 (14C) concentrations which were anomalously high and in excess of theoretical geological maximum concentrations. Further etching of sample material reduced carbon yields and 14C concentrations, yet the latter remained unrealistically high. When quartz from the original whole rock sample was isolated in our laboratory, we observed even lower carbon yields and geologically plausible in situ 14C concentrations. After ruling out unlikely geological scenarios and systematic measurement issues, we decided to investigate the quartz isolation procedure as a potential source of 14C contamination. We hypothesised that laurylamine (dodecylamine), an organic compound used as part of the froth flotation procedure, elevates 14C concentrations if residual laurylamine is present. We demonstrate that laurylamine has a 14C modern carbon source and thus has the potential to influence in situ 14C measurements if present in minute but measurable quantities. Furthermore, we show that insufficient sample etching results in laurylamine-derived carbon persisting through step heating of quartz and is subsequently collected with the in situ component released at 1100 °C. We therefore demonstrate that laurylamine contaminates in situ 14C measurements. We provide guidelines for the preparation of quartz based on methods developed in our laboratory and demonstrate that all laurylamine derived carbon and 14C is removed when applied. We recommend that the procedures presented be used at a minimum when using froth flotation to isolate quartz for in situ 14C measurements.

Download Full-text

Fully Automated System for Aerobic or Anaerobic Sampling of Duodenal Digesta in Sheep or Cattle Equipped with Duodenal Reentrant Cannulas1

Journal of Animal Science ◽

10.2527/jas1985.6051359x ◽

1985 ◽

Vol 60 (5) ◽

pp. 1359-1366 ◽

Cited By ~ 2

Author(s):

M. Ivan ◽

D. J. Buckley ◽

G. St. Amour ◽

C. F. Nicholls ◽

D. M. Veira

Keyword(s):

Automated System ◽

Fully Automated System

Download Full-text

Evaluation of a New Immunochromatography Technology Test (LDBio Diagnostics) To Detect Toxoplasma IgG and IgM: Comparison with the Routine Architect Technique

Journal of Clinical Microbiology ◽

10.1128/jcm.01106-17 ◽

2017 ◽

Vol 55 (12) ◽

pp. 3395-3404 ◽

Cited By ~ 7

Author(s):

Caroline Mahinc ◽

Pierre Flori ◽

Edouard Delaunay ◽

Cécile Guillerme ◽

Sana Charaoui ◽

...

Keyword(s):

Western Blot ◽

Sensitivity And Specificity ◽

Blot Analysis ◽

False Positive ◽

Automated System ◽

University Hospitals ◽

Content Type ◽

Automated Screening ◽

Commercial Kits ◽

Fully Automated System

ABSTRACTA study comparing the ICT (immunochromatography technology)ToxoplasmaIgG and IgM rapid diagnostic test (LDBio Diagnostics, France) with a fully automated system, Architect, was performed on samples from university hospitals of Marseille and Saint-Etienne. A total of 767 prospective sera and 235 selected sera were collected. The panels were selected to test various IgG and IgM parameters. The reference technique,ToxoplasmaIgGII Western blot analysis (LDBio Diagnostics), was used to confirm the IgG results, and commercial kits Platelia Toxo IgM (Bio-Rad) and Toxo-ISAgA (bioMérieux) were used in Saint-Etienne and Marseille, respectively, as the IgM reference techniques. Sensitivity and specificity of the ICT and the Architect IgG assays were compared using a prospective panel. Sensitivity was 100% for the ICT test and 92.1% for Architect (cutoff at 1.6 IU/ml). The low-IgG-titer serum results confirmed that ICT sensitivity was superior to that of Architect. Specificity was 98.7% (ICT) and 99.8% (Architect IgG). The ICT test is also useful for detecting IgM without IgG and is both sensitive (100%) and specific (100%), as it can distinguish nonspecific IgM from specificToxoplasmaIgM. In comparison, IgM sensitivity and specificity on Architect are 96.1% and 99.6%, respectively (cutoff at 0.5 arbitrary units [AU]/ml). To conclude, this new test overcomes the limitations of automated screening techniques, which are not sensitive enough for IgG and lack specificity for IgM (rare IgM false-positive cases).

Download Full-text

METABOLISM OF DEHYDROEPIANDROSTERONE SULPHATE AND OESTRONE SULPHATE FOLLOWING IN SITU PLACENTAL PERFUSION AT MIDPREGNANCY

Acta Endocrinologica ◽

10.1530/acta.0.0660637 ◽

1971 ◽

Vol 66 (4) ◽

pp. 637-647 ◽

Cited By ~ 1

Author(s):

J. Schwers ◽

T. Vancrombreucq ◽

M. Govaerts ◽

G. Eriksson ◽

E. Diczfalusy

Keyword(s):

Radioactive Material ◽

Dehydroepiandrosterone Sulphate ◽

Placental Perfusion ◽

Carbon 14 ◽

Maternal Urine ◽

Oestrone Sulphate ◽

Unchanged Form ◽

Urine Specimens

ABSTRACT Two midgestation placentas were perfused in situ with a combination of [7α-3H] dehydroepiandrosterone sulphate and [4-14C] oestrone sulphate and metabolites were isolated from the placentas, perfusates and maternal urine specimens. Approximately 70 per cent of the perfused radioactive material was recovered from these three sources. The bulk of the administered radioactive material was recovered in an unchanged form from the perfusates; some 2–4 per cent was excreted in the urine and less than 0.5% was found in the placentas. The tritium to carbon-14 ratio of the unconjugated material isolated from the perfusates and placentas was higher, and that of the conjugated material recovered from the same sources was lower than the ratio of the administered material. In addition, more tritium than carbon-14 labelled material was present in the urine. Approximately 2 per cent of the perfused dehydroepiandrosterone sulphate was recovered in the form of phenolic steroids, mostly from the urine. From this source double labelled oestrone, oestriol, 16α-hydroxy-oestrone and 16-epioestriol were isolated. The tritium to carbon-14 ratio of all oestrogens isolated from the urine was higher than that of the perfused material. From the urine specimens 10 to 15 times more double labelled oestriol than oestrone was isolated.

Download Full-text

In situ cosmogenic nuclide production rate calibration for the CRONUS-Earth project from Lake Bonneville, Utah, shoreline features

Quaternary Geochronology ◽

10.1016/j.quageo.2014.11.002 ◽

2015 ◽

Vol 26 ◽

pp. 56-69 ◽

Cited By ~ 52

Author(s):

Nathaniel Lifton ◽

Marc Caffee ◽

Robert Finkel ◽

Shasta Marrero ◽

Kunihiko Nishiizumi ◽

...

Keyword(s):

Production Rate ◽

Lake Bonneville ◽

Cosmogenic Nuclide

Download Full-text

New Last Glacial Maximum ice thickness constraints for the Weddell Sea Embayment, Antarctica

The Cryosphere ◽

10.5194/tc-13-2935-2019 ◽

2019 ◽

Vol 13 (11) ◽

pp. 2935-2951 ◽

Cited By ~ 4

Author(s):

Keir A. Nichols ◽

Brent M. Goehring ◽

Greg Balco ◽

Joanne S. Johnson ◽

Andrew S. Hein ◽

...

Keyword(s):

Sea Level ◽

Last Glacial Maximum ◽

Glacial Maximum ◽

Weddell Sea ◽

Ice Thickness ◽

Last Glacial ◽

Cosmogenic Nuclide ◽

Ice Stream ◽

Exposure Ages

Abstract. We describe new Last Glacial Maximum (LGM) ice thickness constraints for three locations spanning the Weddell Sea Embayment (WSE) of Antarctica. Samples collected from the Shackleton Range, Pensacola Mountains, and the Lassiter Coast constrain the LGM thickness of the Slessor Glacier, Foundation Ice Stream, and grounded ice proximal to the modern Ronne Ice Shelf edge on the Antarctic Peninsula, respectively. Previous attempts to reconstruct LGM-to-present ice thickness changes around the WSE used measurements of long-lived cosmogenic nuclides, primarily 10Be. An absence of post-LGM apparent exposure ages at many sites led to LGM thickness reconstructions that were spatially highly variable and inconsistent with flow line modelling. Estimates for the contribution of the ice sheet occupying the WSE at the LGM to global sea level since deglaciation vary by an order of magnitude, from 1.4 to 14.1 m of sea level equivalent. Here we use a short-lived cosmogenic nuclide, in situ-produced 14C, which is less susceptible to inheritance problems than 10Be and other long-lived nuclides. We use in situ 14C to evaluate the possibility that sites with no post-LGM exposure ages are biased by cosmogenic nuclide inheritance due to surface preservation by cold-based ice and non-deposition of LGM-aged drift. Our measurements show that the Slessor Glacier was between 310 and up to 655 m thicker than present at the LGM. The Foundation Ice Stream was at least 800 m thicker, and ice on the Lassiter Coast was at least 385 m thicker than present at the LGM. With evidence for LGM thickening at all of our study sites, our in situ 14C measurements indicate that the long-lived nuclide measurements of previous studies were influenced by cosmogenic nuclide inheritance. Our inferred LGM configuration, which is primarily based on minimum ice thickness constraints and thus does not constrain an upper limit, indicates a relatively modest contribution to sea level rise since the LGM of < 4.6 m, and possibly as little as < 1.5 m.

Download Full-text

Fully automated cognitive screening tool based on assessment of speech and language

Journal of Neurology Neurosurgery & Psychiatry ◽

10.1136/jnnp-2019-322517 ◽

2020 ◽

Vol 92 (1) ◽

pp. 12-15

Author(s):

Ronan Peter Daniel O'Malley ◽

Bahman Mirheidari ◽

Kirsty Harkness ◽

Markus Reuber ◽

Annalena Venneri ◽

...

Keyword(s):

Cognitive Disorders ◽

Cognitive Disorder ◽

Current Data ◽

Automated System ◽

Cognitive Screening ◽

Machine Learning Classification ◽

Speaker Segmentation ◽

Memory Clinics ◽

Memory Concerns ◽

Fully Automated System

IntroductionRecent years have seen an almost sevenfold rise in referrals to specialist memory clinics. This has been associated with an increased proportion of patients referred with functional cognitive disorder (FCD), that is, non-progressive cognitive complaints. These patients are likely to benefit from a range of interventions (eg, psychotherapy) distinct from the requirements of patients with neurodegenerative cognitive disorders. We have developed a fully automated system, ‘CognoSpeak’, which enables risk stratification at the primary–secondary care interface and ongoing monitoring of patients with memory concerns.MethodsWe recruited 15 participants to each of four groups: Alzheimer’s disease (AD), mild cognitive impairment (MCI), FCD and healthy controls. Participants responded to 12 questions posed by a computer-presented talking head. Automatic analysis of the audio and speech data involved speaker segmentation, automatic speech recognition and machine learning classification.ResultsCognoSpeak could distinguish between participants in the AD or MCI groups and those in the FCD or healthy control groups with a sensitivity of 86.7%. Patients with MCI were identified with a sensitivity of 80%.DiscussionOur fully automated system achieved levels of accuracy comparable to currently available, manually administered assessments. Greater accuracy should be achievable through further system training with a greater number of users, the inclusion of verbal fluency tasks and repeat assessments. The current data supports CognoSpeak’s promise as a screening and monitoring tool for patients with MCI. Pending confirmation of these findings, it may allow clinicians to offer patients at low risk of dementia earlier reassurance and relieve pressures on specialist memory services.

Download Full-text