107 research outputs found
HISTORIA HISTORIOGRAFII: KSIĄŻKA TELEFONICZNA, CZY FRAGMENT SOCJOLOGII WIEDZY?
In this article the author argues for the rapprochement between the methods and questions of the history of historiography and the questionnaire of the sociology of knowledge. The sociological perspective can inspire both the research on the communities of professional historians and the functioning of the historiographical knowledge in social and political structures. The author analyzes diff erent dimensions of the political functions of historiography and emphasizes the diff erence between the utilitarian and scientific aspects of historical knowledge.In this article the author argues for the rapprochement between the methods and questions of the history of historiography and the questionnaire of the sociology of knowledge. The sociological perspective can inspire both the research on the communities of professional historians and the functioning of the historiographical knowledge in social and political structures. The author analyzes diff erent dimensions of the political functions of historiography and emphasizes the diff erence between the utilitarian and scientific aspects of historical knowledge
Czystka etniczna w domu? Joanna Tokarska-Bakir, Bracia miesiące. Studia z antropologii historycznej Polski 1939–1945
Recenzja książki Joanny Tokarskiej-Bakir "Bracia miesiące. Studia z antropologii historycznej Polski 1939–1945" poświęconej sposobom, w jaki nieżydowscy Polacy włączyli się w niemiecki projekt zagłady Żydów podczas wojny i po wojnie
Molecular dynamics and cold crystallization process in a liquid-crystalline substance with para-, ferro- and antiferro-electric phases as studied by dielectric spectroscopy and scanning calorimetry
In this article, molecular dynamics and the cold crystallization kinetics of 4-(6-heptafluorobutanoiloxyhexyloxy)
biphenyl-4′-carboxylan(S)-4-(1-methyloheptyloxycarbonyl) phenyl (abbreviated as 3F6Bi and/or 4H6) are
presented. Rich polymorphismof the liquid-crystalline (SmA*, SmC*, SmC*A and SmI*A) phases and partially disordered
crystal CrI and glassy GCrI were observed upon cooling. Both, molecular and collective relaxation processes
were observed in the para-, ferro- and antiferro-electric liquid-crystalline phases over the frequency
range of 3 × 10−2 to 3 × 106 Hz. An additional bias field in the dielectric experiments was used to identify
individual processes. The high heating rates (5–10 K/min) phase sequence is the same as in case of the cooling
experiment. On slow heating (0.5–2 K/min), cold crystallization of SmI*A to the more stable crystal CrII phase
was observed in the dielectric and calorimetric experiments. The crystallization kinetics was analyzed using
the Mo equation, which is a combination of the Avrami and Ozawa models. The activation energy of crystallization
was calculated to be 138 and 99 kJ/mol using the Kissinger and Augis-Bennett models, respectively
(3+2)‐Cyclization Reactions of Unsaturated Phosphonites with Aldehydes and Thioketones
By exploiting the unique reactivity of ethynyl‐phosphonites we obtain novel P(V)‐containing five‐membered heterocycles via (3+2)‐cyclization reactions with aldehydes or cycloaliphatic thioketones in satisfactory to excellent yields. Whereas reactions with thioketones to yield 1,3‐thiaphospholes‐3‐oxides occur smoothly at room temperature with equimolar amounts of the starting materials in absence of any catalyst, the analogous conversions with aldehydes to generate 3‐oxides of 1,3‐oxaphospholes require addition of triethylamine as a base. We postulate a step‐wise (3+2)‐cyclization mechanism for the formation of the 1,3‐thiaphosphole ring based on DFT quantum chemical calculations. With this study, we introduce new cyclization reactions originating from unsaturated phosphonites as central synthetic building blocks to yield previously inaccessible stable phosphorus‐containing heterocycles with unexplored potential for the molecular sciences.Deutsche Forschungsgemeinschaft
http://dx.doi.org/10.13039/501100001659Alexander von Humboldt-Stiftung
http://dx.doi.org/10.13039/100005156Peer Reviewe
Identification of Unknown Protein Function Using Metabolite Cocktail Screening
SummaryProteins of unknown function comprise a significant fraction of sequenced genomes. Defining the roles of these proteins is vital to understanding cellular processes. Here, we describe a method to determine a protein function based on the identification of its natural ligand(s) by the crystallographic screening of the binding of a metabolite library, followed by a focused search in the metabolic space. The method was applied to two protein families with unknown function, PF01256 and YjeF_N. The PF01256 proteins, represented by YxkO from Bacillus subtilis and the C-terminal domain of Tm0922 from Thermotoga maritima, were shown to catalyze ADP/ATP-dependent NAD(P)H-hydrate dehydratation, a previously described orphan activity. The YjeF_N proteins, represented by mouse apolipoprotein A-I binding protein and the N-terminal domain of Tm0922, were found to interact with an adenosine diphosphoribose-related substrate and likely serve as ADP-ribosyltransferases. Crystallographic screening of metabolites serves as an efficient tool in functional analyses of uncharacterized proteins
In-depth studies of ground- and excited-state properties of Re(I) carbonyl complexes bearing 2,2′:6′,2′′-terpyridine and 2,6-bis(pyrazin-2-yl)pyridine coupled with π‑conjugated aryl chromophores
In the current work, comprehensive photophysical and electrochemical
studies were performed for eight rhenium(I) complexes incorporating
2,2′:6′,2″-terpyridine (terpy) and 2,6-bis(pyrazin-2-yl)pyridine (dppy) with
appended 1-naphthyl-, 2-naphthyl-, 9-phenanthrenyl, and 1-pyrenyl groups.
Naphthyl and phenanthrenyl substituents marginally affected the energy of the
MLCT absorption and emission bands, signaling a weak electronic coupling of
the appended aryl group with the Re(I) center. The triplet MLCT state in these
complexes is so low lying relative to the triplet 3ILaryl that the thermal population
of the triplet excited state delocalized on the organic chromophore is ineffective.
The attachment of the electron-rich pyrenyl group resulted in a noticeable red
shift and a significant increase in molar absorption coefficients of the lowest
energy absorption of the resulting Re(I) complexes due to the contribution of
intraligand charge-transfer (ILCT) transitions occurring from the pyrenyl
substituent to the terpy/dppy core. At 77 K, the excited states of [ReCl(CO)3(Ln-κ2N)] with 1-pyrenyl-functionalized ligands
were found to have predominant 3ILpyrene/3ILCTpyrene→terpy character. The 3IL/3ILCT nature of the lowest energy excited state of
[ReCl(CO)3(4′-(1-pyrenyl)-terpy-κ2N)] was also evidenced by nanosecond transient absorption and time-resolved emission
spectroscopy. Enhanced room-temperature emission lifetimes of the complexes [ReCl(CO)3(Ln-κ2N)] with 1-pyrenyl-substituted
ligands are indicative of the thermal activation between 3MLCT and 3IL/3ILCT excited states. Deactivation pathways occurring
upon light excitation in [ReCl(CO)3(4′-(1-naphthyl)-terpy-κ2N)] and [ReCl(CO)3(4′-(1-pyrenyl)-terpy-κ2N)] were determined by
femtosecond transient absorption studies
X-ray Microtomography Analysis of the Aluminum Alloy Composite Reinforced by SiC After Friction Stir Processing
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