scholarly journals Radiocarbon Dating of Pleistocene Bone: Toward Criteria for the Selection of Samples

Radiocarbon ◽  
1980 ◽  
Vol 22 (3) ◽  
pp. 969-979 ◽  
Author(s):  
R E Taylor
Keyword(s):  
Amino Acid ◽  
Stable Isotope ◽  
Amino Acid Composition ◽  
Radiocarbon Dating ◽  
Detection System ◽  
High Energy ◽  
Mass Spectrometric ◽  
Stable Isotope Ratios ◽  
Sources Of Information ◽  
Selection Of

Amino acid composition data and stable isotope ratios (14N, D, and13C) are being evaluated as sources of information to indicate the presence of non-indigenous organics in bone samples intended for 14C analyses. The study is being conducted in the context of the planned measurement of Pleistocene bone samples by a high energy mass spectrometric 14C detection system.

Can the (M• — X) Region in Electron Capture Dissociation Provide Reliable Information on Amino Acid Composition of Polypeptides?

2002 ◽  
Vol 8 (6) ◽  
pp. 461-469 ◽  
Author(s):  
Kim F. Haselmann ◽  
Bogdan A. Budnik ◽  
Frank Kjeldsen ◽  
Nicolas C. Polfer ◽  
Roman A. Zubarev
Keyword(s):  
Amino Acid ◽  
Hydrogen Atom ◽  
Amino Acid Composition ◽  
Electron Capture ◽  
Acid Composition ◽  
Electron Capture Dissociation ◽  
Diagnostic Value ◽  
High Energy ◽  
Mass Spectrom ◽  
Charge Solvation

It has been suggested that small losses from reduced peptide molecular species in electron capture dissociation (ECD) could indicate the presence of certain amino acids [H.J. Cooper, R.R. Hudgins, K. Håkansson and A.G. Marshall, J. Am Soc. Mass Spectrom 13, 241 (2002)], similarly to immonium ions in high-energy collision-activated dissociation. The diagnostic value in ECD of the (M•–X) region (1 Da ≤ X ≤ 130 Da) was tested on several synthetic peptides. The insufficiency of the existing knowledge for making correct conclusions on the amino acid composition is demonstrated and new suggestions of the origin of losses are presented based on the “hot hydrogen atom” ECD mechanism. Generally, it is shown that not only protonation but also charge solvation is responsible for the small losses. The origin of 17 Da and 59 Da losses is revisited and a new mechanism for the 18 Da loss is suggested. The loss of a side chain plus a hydrogen atom is found to be a rather reliable indicator of the presence of histidine, tryptophan, tyrosine and, to a lesser degree, threonine. The overall conclusion is that the (M• - X) region does contain information on the amino acid composition, but extraction of this information requires additional studies.

scholarly journals Selection of Ig μ Heavy Chains by Complementarity-Determining Region 3 Length and Amino Acid Composition

2003 ◽  
Vol 171 (9) ◽  
pp. 4663-4671 ◽  
Author(s):  
Denise A. Martin ◽  
Harald Bradl ◽  
Tara J. Collins ◽  
Edith Roth ◽  
Hans-Martin Jäck ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Heavy Chains ◽  
Complementarity Determining Region ◽  
Selection Of

Unusual stable isotope ratios in amino acid and carboxylic acid extracts from the Murchison meteorite

Nature ◽  
1987 ◽  
Vol 326 (6112) ◽  
pp. 477-479 ◽  
Author(s):  
S. Epstein ◽  
R. V. Krishnamurthy ◽  
J. R. Cronin ◽  
S. Pizzarello ◽  
G. U. Yuen
Keyword(s):  
Amino Acid ◽  
Carboxylic Acid ◽  
Stable Isotope ◽  
Isotope Ratios ◽  
Stable Isotope Ratios ◽  
Murchison Meteorite

scholarly journals Effect of Sweetness Level and Amino Acid Composition of Palm Sugar on Feed Intake of Trichoglossus haematodus in Captivity

2020 ◽  
Vol 12 (2) ◽  
pp. 254-261
Author(s):  
Siti Nuramaliati Prijono ◽  
Rini Rachmatika
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Feed Intake ◽  
High Energy ◽  
Sweet Taste ◽  
Sugar Solution ◽  
Randomized Design ◽  
In Captivity ◽  
Palm Sugar

Palm sugar solution diets that were offered to the Lorikeets contain  high energy, low protein and rich in amino acids similar to nectar. The major components of palm sugar are sucrose, which has a sweet taste. The Lorikeets  can detect energy-rich from the sweet taste of the feed. The aim of the study was to determine the influence of sweetness level and amino acid composition in palm sugar solution diets on feed intake of T. haematodus. The research method was completely randomized design arranged in a factorial with two factors. The first factor consisted of 4 types of palm sugars, i.e.   aren, coconut, siwalan/palmyra, and nipah sugar with a different degree Brix in 13.5º, 14.0º, 14.5º, and 15.0º Brix.While the second factor consisted of two treatments, with and without the addition of the commercial baby biscuit. The results showed that the feed intake of Siwalan sugar was significantly higher than the other palm sugar solution diets. Siwalan sugar solution diet has high sweetness level, sucrose content and essential amino acid Lysine. This study provides the new information regarding the sweetness level of palm sugar and amino acid composition in the diet that can affect feed intake of T. haematodus. Therefore, this information will help to make a formulation of appropriate diet that meets the nutrient requirements especially amino acid for the birds.

scholarly journals Radiocarbon Dating of Biochemically Characterized Hair

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 319-330 ◽  
Author(s):  
R. E. Taylor ◽  
P. E. Hare ◽  
Christine A. Prior ◽  
Donna L. Kirner ◽  
Lijun Wan ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Radiocarbon Dating ◽  
Baseline Data ◽  
Data Support ◽  
Hair Samples ◽  
Before And After ◽  
Age Determinations

A series of 14C determinations have been obtained on hair samples principally from Holocene contexts that have been variously pretreated to examine different means of removing potential contamination. SEM photomicrographs have documented hair surfaces before and after different pretreatments. Amino-acid composition, C/N ratios and δ13C values have been obtained to biochemically characterize these samples and provide baseline data for future comparisons with less well-preserved samples. Our data support the view that appropriately pretreated hair samples can provide accurate 14C age determinations.

Analysis of electron-diffraction intensity profiles using a photodiode-array detection system

1983 ◽  
Vol 41 ◽  
pp. 322-323
Author(s):  
J. B. Warren
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Detection System ◽  
High Energy ◽  
Photographic Emulsion ◽  
Diffraction Intensity ◽  
Silicon Photodiode ◽  
Photodiode Array Detection ◽  
Analog To Digital ◽  
Photodiode Array

Electron diffraction intensity profiles have been used extensively in studies of polycrystalline and amorphous thin films. In previous work, diffraction intensity profiles were quantitized either by mechanically scanning the photographic emulsion with a densitometer or by using deflection coils to scan the diffraction pattern over a stationary detector. Such methods tend to be slow, and the intensities must still be converted from analog to digital form for quantitative analysis. The Instrumentation Division at Brookhaven has designed and constructed a electron diffractometer, based on a silicon photodiode array, that overcomes these disadvantages. The instrument is compact (Fig. 1), can be used with any unmodified electron microscope, and acquires the data in a form immediately accessible by microcomputer.Major components include a RETICON 1024 element photodiode array for the de tector, an Analog Devices MAS-1202 analog digital converter and a Digital Equipment LSI 11/2 microcomputer. The photodiode array cannot detect high energy electrons without damage so an f/1.4 lens is used to focus the phosphor screen image of the diffraction pattern on to the photodiode array.

Spatial Representations as an Emergent Feature of Perceptual Processing

2010 ◽  
Vol 24 (3) ◽  
pp. 161-172 ◽  
Author(s):  
Edmund Wascher ◽  
C. Beste
Keyword(s):  
Common Ground ◽  
Event Related Potentials ◽  
Vertical Axis ◽  
Relevant Information ◽  
Sources Of Information ◽  
Integrated Network ◽  
Perceptual Maps ◽  
Emergent Feature ◽  
Related Potentials ◽  
Selection Of

Spatial selection of relevant information has been proposed to reflect an emergent feature of stimulus processing within an integrated network of perceptual areas. Stimulus-based and intention-based sources of information might converge in a common stage when spatial maps are generated. This approach appears to be inconsistent with the assumption of distinct mechanisms for stimulus-driven and top-down controlled attention. In two experiments, the common ground of stimulus-driven and intention-based attention was tested by means of event-related potentials (ERPs) in the human EEG. In both experiments, the processing of a single transient was compared to the selection of a physically comparable stimulus among distractors. While single transients evoked a spatially sensitive N1, the extraction of relevant information out of a more complex display was reflected in an N2pc. The high similarity of the spatial portion of these two components (Experiment 1), and the replication of this finding for the vertical axis (Experiment 2) indicate that these two ERP components might both reflect the spatial representation of relevant information as derived from the organization of perceptual maps, just at different points in time.

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