An X-ray examination of geometrical factors affecting conjugative overlap between a cyclopropane ring and an adjacent chromophore in two 3,5-cyclosteroid derivatives

1972 ◽  
pp. 1929 ◽  
Author(s):  
Roger C. Pettersen ◽  
Olga Kennard ◽  
William G. Dauben
Keyword(s):  
Cyclopropane Ring ◽  
Factors Affecting ◽  
X Ray ◽  
Geometrical Factors

A Camera for Borrmann Stereo X-Ray Topographs

1965 ◽  
Vol 9 ◽  
pp. 1-13 ◽  
Author(s):  
F. W. Young ◽  
T. O. Baldwin ◽  
A. E. Merlini ◽  
F. A. Sherrill
Keyword(s):  
Resolving Power ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
X Ray ◽  
Diffraction Phenomenon ◽  
Anomalous Transmission ◽  
Geometrical Factors ◽  
Copper Crystals

AbstractA relatively inexpensive camera which was designed for taking Borrmann topographs with standard X-ray diffraction equipment is described. This camera has been used to take stereo pairs of Borrmann topographs by rotating the crystal around an axis normal to the diffraction planes. Topographs have been taken of nearly perfect copper crystals up to 0.2 cm thick using silver, molybdenum, copper, and chromium radiation, and comparisons have been made with topographs obtained with crystal monochromated radiation. Geometrical factors affecting the resolving power of the technique are briefly reviewed. In addition, the resolution inherent in the diffraction phenomenon is analyzed on the basis of the theory of anomalous transmission. Comparisons are made between calculated and observed image widths of a few dislocations.

Pediatric Minor Head Trauma: Factors Affecting the Anxiety of Parents

2021 ◽  
pp. 000992282110096
Author(s):  
Hasan Aldinc ◽  
Cem Gun ◽  
Serpil Yaylaci ◽  
Erol Barbur
Keyword(s):  
Computed Tomography ◽  
Head Trauma ◽  
Pediatric Patients ◽  
Positive Impact ◽  
Cranial Computed Tomography ◽  
Sufficient Information ◽  
Minor Head Trauma ◽  
Computed Tomography Imaging ◽  
Factors Affecting ◽  
X Ray

Managing the anxiety of the parents of pediatric patients with head trauma is challenging. This study aimed to examine the factors that affect anxiety levels of parents whose children were admitted to the emergency department with minor head trauma. In this prospective study, the parents of 663 consecutive pediatric patients were invited to answer a questionnaire. Parents of 600 children participated in the study. The parents who believed they were provided sufficient information and who were satisfied with the service received had significantly more improvement in anxiety-related questions. Cranial X-ray assessment had a significantly positive impact on the anxiety of the parents, whereas cranial computed tomography and neurosurgery consultation did not. In assessing pediatric minor head trauma, cranial computed tomography imaging and neurosurgery consultation should not be expected to relieve the anxiety of the parents. However, adequately informing them and providing satisfaction are the factors that could lead to improvement.

scholarly journals Seasonal changes in Fe species and soluble Fe concentration in the atmosphere in the Northwest Pacific region based on the analysis of aerosols collected in Tsukuba, Japan

2013 ◽  
Vol 13 (15) ◽  
pp. 7695-7710 ◽  
Author(s):  
Y. Takahashi ◽  
T. Furukawa ◽  
Y. Kanai ◽  
M. Uematsu ◽  
G. Zheng ◽  
...  
Keyword(s):  
Fossil Fuel ◽  
Fuel Combustion ◽  
Anthropogenic Sources ◽  
Anthropogenic Activity ◽  
Northwest Pacific ◽  
Pacific Region ◽  
Fossil Fuel Combustion ◽  
Factors Affecting ◽  
X Ray ◽  
Fe Species

Abstract. Atmospheric iron (Fe) can be a significant source of nutrition for phytoplankton inhabiting remote oceans, which in turn has a large influence on the Earth's climate. The bioavailability of Fe in aerosols depends mainly on the fraction of soluble Fe (= [FeSol]/[FeTotal], where [FeSol] and [FeTotal] are the atmospheric concentrations of soluble and total Fe, respectively). However, the numerous factors affecting the soluble Fe fraction have not been fully understood. In this study, the Fe species, chemical composition, and soluble Fe concentrations in aerosols collected in Tsukuba, Japan were investigated over a year (nine samples from December 2002 to October 2003) to identify the factors affecting the amount of soluble Fe supplied into the ocean. The soluble Fe concentration in aerosols is correlated with those of sulfate and oxalate originated from anthropogenic sources, suggesting that soluble Fe is mainly derived from anthropogenic sources. Moreover, the soluble Fe concentration is also correlated with the enrichment factors of vanadium and nickel emitted by fossil fuel combustion. These results suggest that the degree of Fe dissolution is influenced by the magnitude of anthropogenic activity, such as fossil fuel combustion. X-ray absorption fine structure (XAFS) spectroscopy was performed in order to identify the Fe species in aerosols. Fitting of XAFS spectra coupled with micro X-ray fluorescence analysis (μ-XRF) showed the main Fe species in aerosols in Tsukuba to be illite, ferrihydrite, hornblende, and Fe(III) sulfate. Moreover, the soluble Fe fraction in each sample measured by leaching experiments is closely correlated with the Fe(III) sulfate fraction determined by the XAFS spectrum fitting, suggesting that Fe(III) sulfate is the main soluble Fe in the ocean. Another possible factor that can control the amount of soluble Fe supplied into the ocean is the total Fe(III) concentration in the atmosphere, which was high in spring due to the high mineral dust concentrations during spring in East Asia. However, this factor does not contribute to the amount of soluble Fe to a larger degree than the effect of Fe speciation, or more strictly speaking the presence of Fe(III) sulfate. Therefore, based on these results, the most significant factor influencing the amount of soluble Fe in the North Pacific region is the concentration of anthropogenic Fe species such as Fe(III) sulfate that can be emitted from megacities in Eastern Asia.

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.

Instrument-related geometrical factors affecting the intensity in XPS and ARXPS experiments

2011 ◽  
Vol 184 (8-10) ◽  
pp. 487-500 ◽  
Author(s):  
A. Herrera-Gomez ◽  
F.S. Aguirre-Tostado ◽  
P.G. Mani-Gonzalez ◽  
M. Vazquez-Lepe ◽  
A. Sanchez-Martinez ◽  
...  
Keyword(s):  
Factors Affecting ◽  
Geometrical Factors
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