scholarly journals Chemical Composition of Insoluble Particles in an Ice Cap on Storøya, Svalbard (Abstract)

1988 ◽  
Vol 10 ◽  
pp. 204-204
Author(s):  
Jost Heintzenberg ◽  
Margareta Källström ◽  
Hans-Christen Hansson ◽  
Stig Jonsson
Keyword(s):  
Statistical Analysis ◽  
Chemical Composition ◽  
Elemental Carbon ◽  
Ice Core ◽  
Multivariate Statistical ◽  
Factors Affecting ◽  
X Ray ◽  
Ice Cap ◽  
Insoluble Particles ◽  
Major Factors

During the Ymer-80 expedition, a 6 m long ice core was taken on the low-lying ice cap Storøyjøkulen, Svalbard. Core samples of about 10 ml were filtered on 0.1 μm pore-size Nuclepore filters, for analysis with a soot photometer and by means of particle-induced X-ray emission, which yielded elemental carbon and about 15 metals in the insoluble microparticles. The concentrationswere comparable to Arctic snow data from other locations. Multivariate statistical analysis of the chemical results indicates two major factors affecting microparticle composition: crustal and anthropogenic. A regular seasonal concentration pattern was found which is consistent with the c. 40 cm annual accumulation deduced from mass-balance studies on the ice cap.

scholarly journals Chemical Composition of Insoluble Particles in an Ice Cap on Storøya, Svalbard (Abstract)

1988 ◽  
Vol 10 ◽  
pp. 204 ◽  
Author(s):  
Jost Heintzenberg ◽  
Margareta Källström ◽  
Hans-Christen Hansson ◽  
Stig Jonsson
Keyword(s):  
Statistical Analysis ◽  
Chemical Composition ◽  
Elemental Carbon ◽  
Ice Core ◽  
Multivariate Statistical ◽  
Factors Affecting ◽  
X Ray ◽  
Ice Cap ◽  
Insoluble Particles ◽  
Major Factors

During the Ymer-80 expedition, a 6 m long ice core was taken on the low-lying ice cap Storøyjøkulen, Svalbard. Core samples of about 10 ml were filtered on 0.1 μm pore-size Nuclepore filters, for analysis with a soot photometer and by means of particle-induced X-ray emission, which yielded elemental carbon and about 15 metals in the insoluble microparticles. The concentrations were comparable to Arctic snow data from other locations. Multivariate statistical analysis of the chemical results indicates two major factors affecting microparticle composition: crustal and anthropogenic. A regular seasonal concentration pattern was found which is consistent with the c. 40 cm annual accumulation deduced from mass-balance studies on the ice cap.

scholarly journals Chemical Species, Micromorphology, and XRD Fingerprint Analysis of Tibetan MedicineZuotaiContaining Mercury

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Cen Li ◽  
Hongxia Yang ◽  
Yuzhi Du ◽  
Yuancan Xiao ◽  
Zhandui ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Multivariate Statistical Analysis ◽  
Chemical Species ◽  
Physicochemical Characteristics ◽  
Chemical Substance ◽  
Tibetan Medicine ◽  
Fingerprint Analysis ◽  
Multivariate Statistical ◽  
Positive Role ◽  
X Ray

Zuotai(gTso thal) is one of the famous drugs containing mercury in Tibetan medicine. However, little is known about the chemical substance basis of its pharmacodynamics and the intrinsic link of different samples sources so far. Given this, energy dispersive spectrometry of X-ray (EDX), scanning electron microscopy (SEM), atomic force microscopy (AFM), and powder X-ray diffraction (XRD) were used to assay the elements, micromorphology, and phase composition of nineZuotaisamples from different regions, respectively; the XRD fingerprint features ofZuotaiwere analyzed by multivariate statistical analysis. EDX result shows thatZuotaicontains Hg, S, O, Fe, Al, Cu, and other elements. SEM and AFM observations suggest thatZuotaiis a kind of ancient nanodrug. Its particles are mainly in the range of 100–800 nm, which commonly further aggregate into 1–30 μm loosely amorphous particles. XRD test shows thatβ-HgS, S8, andα-HgS are its main phase compositions. XRD fingerprint analysis indicates that the similarity degrees of nine samples are very high, and the results of multivariate statistical analysis are broadly consistent with sample sources. The present research has revealed the physicochemical characteristics ofZuotai, and it would play a positive role in interpreting this mysterious Tibetan drug.

Factors affecting the amplitude of the τ angle in proteins: a revisitation

2017 ◽  
Vol 73 (7) ◽  
pp. 618-625 ◽  
Author(s):  
Nicole Balasco ◽  
Luciana Esposito ◽  
Luigi Vitagliano
Keyword(s):  
Protein Structures ◽  
Factors Affecting ◽  
X Ray ◽  
Backbone Conformation ◽  
Potential Factors ◽  
The Stability ◽  
Major Factors ◽  
The Impact ◽  
Open Issues

The protein folded state is the result of the fine balance of a variety of different forces. Even minor structural perturbations may have a significant impact on the stability of these macromolecules. Studies carried out in recent decades have led to the convergent view that proteins are endowed with a flexible spine. One of the open issues related to protein local backbone geometry is the identification of the factors that influence the amplitude of the τ (N—Cα—C) angle. Here, statistical analyses performed on an updated ensemble of X-ray protein structures by dissecting the contribution of the major factors that can potentially influence the local backbone geometry of proteins are reported. The data clearly indicate that the local backbone conformation has a prominent impact on the modulation of the τ angle. Therefore, a proper assessment of the impact of the other potential factors can only be appropriately evaluated when small (φ, ψ) regions are considered. Here, it is shown that when the contribution of the backbone conformation is removed by considering small (φ, ψ) areas, an impact of secondary structure, as defined byDSSP, and/or the residue type on τ is still detectable, although to a limited extent. Indeed, distinct τ-value distributions are detected for Pro/Gly and β-branched (Ile/Val) residues. The key role of the local backbone conformation highlighted here supports the use of variable local backbone geometry in protein refinement protocols.

scholarly journals Multivariate Statistical Analysis of Particle X-ray Spectra

1998 ◽  
Vol 4 (S2) ◽  
pp. 202-203
Author(s):  
Ian M. Anderson ◽  
John A. Small
Keyword(s):  
Statistical Analysis ◽  
Trace Element ◽  
Multivariate Statistical Analysis ◽  
A Priori ◽  
Detectable Level ◽  
Multivariate Statistical ◽  
Raw Data ◽  
X Ray ◽  
Carbon Substrates ◽  
Particle Spectra

Multivariate statistical analysis (MSA) is a powerful tool for the analysis of series of spectra. This paper explores an application of MSA to a series of energy dispersive X-ray (EDX) spectra acquired in the scanning electron microscope (SEM) from a series of particles. The raw data were series of spectra previously acquired to test analytical procedures for trace element detection. This paper explores the possibility of performing the trace element detection with MSA components that have been extracted from the raw data without any a priori assumptions about the information content of the particle spectra. Particles were prepared from two analytical glasses, dispersed onto carbon substrates and coated with carbon. The compositions of the two glasses are substantially similar, except that one glass (K-3106) contains 0.7 wt.% Fe, whereas the other glass (K-3069) does not contain Fe at a detectable level.

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