1,721,218 research outputs found
The titanocene dicarbonyl dication [TiCp2(CO)2]2+
No full textTwo-electron oxidation of TiCp2(CO)2 or double
protonation of TiCp4 in toluene under carbon monoxide
affords an exceedingly moisture-sensitive solid which has
been isolated and identified as the tetraphenylborato
derivative of the titanocene dicarbonyl dication [TiCp2-
(CO)2]2+ on the basis of both spectroscopic data and
reactivity
Effect of Intravenous IgM-Enriched Immunoglobulins on Presepsin and Other Sepsis Biomarkers
No full textPatients in septic shock with low IgG and IgM serum concentrations have higher mortality rates compared to those with normal immunoglobulin levels and, therefore, there is a rational explanation to administer intravenous IgM-enriched immunoglobulins to septic patients in ICU. Aim of this study is to evaluate the effectiveness of intravenous IgM-enriched immunoglobulins in decreasing several sepsis biomarker concentrations. 26 sepsis patients were enrolled in this observational cohort study and Nitric Oxide, Endocan, Pentraxin and presepsin serum levels were measured during their first 3 days of ICU stay. The use of intravenous IgM-enriched immunoglobulins did not influence the temporal evolution of SOFA, Nitric Oxide, Endocan, Pentraxin and Presepsin in the first 3 days of ICU stay in a statistically significant manner, even if Presepsin decreased of 25% from day 1 to day 2 in the Pentaglobin group. It seems possible that Pentaglobin infusion reduces the Presepsin level in a more effective way if it were administered to a younger population (p = 0.012). In conclusion, age modifies the response of Presepsin to Pentaglobin and is a critical variable when investigating the effect of intravenous IgM-enriched immunoglobulins on sepsis
Redox reactions of low-valent Group 4 organometallics with 9,10-phenanthrenequinone (PQ). Crystal and molecular structure of a 10-membered tetraoxometallacycle of bis(cyclopentadienyl)zirconium(IV)
No full textThe bis(arene) derivative of titanium(0), Ti(h6-toluene)2, reacts with 9,10-phenanthrenequinone (PQ) with release of tile arene ligands
and formation of a diamagnetic brown compound best formulated as a dinuclear titanium(IV) derivative containing both 9,10-phenanthrenesemiquinone
(PSQ) and 9,10-phenanthrenediolato (PDA) ligands. MCp2(CO) 2 (M = Zr, Hf) react with PQ to give MCp2PDA which
has been characterized by single crystal X-ray diffractometry for M = Zr. Crystal data: C48H 3604Zr2, M = 859.26 g mol-1, monoclinic,
space group P21/n (No. 14), a = 11.647(8), b = 17.07(1), c = 18.80(1),~, /3= 97.17(6) °, V= 3709(7)A 3, Z= 4, dcalc := 1.539gcm -3,
bt = 5.97 cm -~, F(000) = 1744. The structure consists of dinuclear [ZrCp2PDA] 2 units, the two ZrCp2 groups being bridged by the PDA
ligands to give a 10-membered tetraoxazirconacycle
The tetracyclopentadienyls of titanium, zirconium and hafnium: new synthetic procedures and reactivity
No full textIn toluene as medium, the tetra(cyclopentadienyl) derivatives of Group 4 elements, MCp4 (MTi, Zr, Hf), have been prepared
in high yields from MCp2Cl2 and NaCp. The reactivity of ZrCp4 with species containing active protons such as Ph3SiOH or strong
acids has been studied. Substituted bis(cyclopentadienyl) derivatives were produced except in the case of the reaction between
ZrCp4 and CF3SO3H. In this case, the tris(cyclopentadienyl) derivative ZrCp3(CF3SO3) was obtained as a pale yellow crystalline
material, reactive with water to give the m-oxo derivative of zirconium(IV), [ZrCp2(CF3SO3)]2O, which has been characterized by
standard methods and by X-ray diffraction. Crystal data: C22H20F6O7S2Zr2, M756.96 g mol1, monoclinic, space group C2:c
(no. 15), a19.525(4), b9.028(2), c16.152(5) A°
, b107.31(2)°, V2718.2(1) A°
3, Z4, dcalc1.850 g cm3, l(Cu–Ka)
1.54184 A°
, T291 K, m85.66 cm1, F(000)1496, R0.054, Rw0.049
Smoothing of Slug Tests for Laboratory Scale Aquifer Assessment—A Comparison among Different Porous Media
No full textA filtering analysis of hydraulic head data deduced from slug tests injected in a confined aquifer with different porous media is proposed. Experimental laboratory tests were conducted in a large-scale physical model developed at the University of Calabria. The hydraulic head data were deduced from the records of a pressure sensor arranged in the injection well and subjected to a processing operation to filter the high-frequency noise. The involved smoothing techniques are the Fourier transform and two types of wavelet transform. The performances of the filtered hydraulic heads were examined for different slug volumes and four model layouts in terms of optimal fitting of the Cooper's analytical solution. The hydraulic head variations in the confined aquifer were analyzed using wavelet transform in order to discover their energy contributions and frequency oscillations. Finally, the raw and smoothed hydraulic heads were adopted to calculate the hydraulic conductivity of the aquifer
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
