Search results for "stereo"
showing 10 items of 6147 documents
Toward Anticancer Immunotherapeutics: Well-Defined Polymer-Antibody Conjugates for Selective Dendritic Cell Targeting
2014
This paper describes the synthesis of semitelechelic maleimide-modified N-(2-hydroxypropyl)methacrylamid) (HPMA) based polymers of narrow dispersity that can be conjugated e.g. to anti-DEC-205 antibodies affording "star-like" topologies (one antibody decorated with several polymer chains). FCS revealed a hydrodynamic diameter of R(h) = 7.9 nm and SEC narrow dispersity (1.45). Primary in vitro studies with bone marrow derived dendritic cells (DC) show higher cellular binding and uptake rates compared to control samples. Moreover, incubating these conjugates to primary splenocytes demonstrates a much higher affinity to the primary DCs than to any other immune cell population within the splee…
Understanding the stereo- and regioselectivities of the polar Diels-Alder reactions between 2-acetyl-1,4-benzoquinone and methyl substituted 1,3-buta…
2009
The polar Diels–Alder (DA) reactions of 2-acetyl-1,4-benzoquinone (acBQ) with methyl substituted 1,3-butadienes have been studied using DFT methods at the B3LYP/6-31G(d) level of theory. These reactions are characterized by a nucleophilic attack of the unsubstituted ends of the 1,3-dienes to the β conjugated position of the acBQ followed by ring-closure. The reactions present a total regioselectivity and large endo selectivity. The analysis based on the global electrophilicity of the reagents at the ground state, and the natural bond orbital (NBO) population analysis at the transition states correctly explain the polar nature of these cycloadditions. The large electrophilic character of acB…
Population analysis of pair densities. A study on cyclic systems
2000
Abstract Pair population analysis seems a reliable method for evaluating atomic valency states and bond orders from the MO wavefunction of molecular systems. A test on some cyclic organic systems was performed. The results confirm the capability of the method to provide a correct description of the molecules in terms of simple VB approach.
Influence of Bond Fixation in Benzo-Annulated N-Salicylideneanilines and Their ortho-C(O)X Derivatives (X = CH3, NH2, OCH3) on Tautomeric Equilibria …
2007
1H, 13C, and 15N NMR spectra show that an ortho-C(=O)X group present in the molecules of N-salicylideneanthranilamide (X = NH2), methyl N-salicylideneanthranilate (X = OCH3), N-salicylidene-o-aminoacetophenone (X = CH3), and their benzo analogues have only a minor effect on the tautomeric OH/NH-equilibrium in solution. Only two of three possible tautomers were detected. Lability of the absent form was proved by theoretical calculations. Calculated energies show that the enolimino form (OH) is less stable than the enaminone (NH) form only for dibenzo-annulated N-salicylideneanilines. The population of each species in the tautomeric mixture was found to be inversely proportional to its energy…
Theoretical study of selective H3 receptor antagonists of histamine
1993
Abstract The conformations and charge distributions of three selective H3 receptor antagonists of histamine were determined using the MNDO approach. The results suggest that the conformational flexibilities of betahistine, N α-(2-phenylacetyl)histamine and thioperamide are different; however, the low-energy conformations of these compounds show closely related spatial orderings. The MNDO calculations predict a significant population of the N1H form in the imidazole systems of N α-(2-phenylacetyl)histamine and thioperamide. Our results indicate that the conformational behaviour of H3 antagonists is closely similar to that reported for H2 antagonists of histamine. These results emphasize the …
THE FINE STRUCTURE OF O2 Hb BINDING IN ANIMALS: SALMO IRIDEUS
1980
Publisher Summary This chapter discusses the experimental results on study of the fine structure of O 2 Hb binding in animals. It is evident that the n ( S ) function represents a new tool to look at homotropic interactions, both qualitatively and quantitatively. At the moment, there are four applications: (1) study of molecular mechanism; (2) study of effectors, also pharmacological; (3) improved characterization of O 2 Hb binding, also in pathological cases; and (4) comparative studies in animals. Whole blood of fish is also investigated because usually there are found several hemoglobins. During registration of the O 2 binding curve, pH is not kept constant. Assuming that the Donnan fact…
CT and MR Imaging of Brain Tumors
1989
Our clinical population numbered 8516 patients with primary and metastatic brain tumors who underwent evaluation by computed tomography at the neurosurgical and neuroradiologic departments of the Berlin, Mainz, and Munich centers from 1975 to 1986 and at the Neurosurgical Department of Augsburg Central Hospital from 1983 to 1986. Table 5 lists all the tumors having an incidence greater than 1% in the total population; 98% of the lesions were confirmed histologically (open surgery, stereotactic biopsy, autopsy). “Rare” intracranial tumors having an incidence no greater than 1% are listed in Table 6. The frequencies of the individual tumor types correlate well with the statistical data report…
Gas phase behavior of radical cations of perfluoroalkyl-1,2,4-triazines: an experimental and theoretical study
2009
Electron ionization mass spectrometry and low-energy collision-induced decomposition reactions occurring in a tridimensional ion trap, together with density functional theory (DFT) calculations on neutrals, even- and odd-electron cations, have been used to study the gas-phase ion chemistry of a series of perfluoroalkyl-1,2,4-triazines. Loss of oxygen, due to thermal degradation occurring before ionization, likely involving the hydroxylamino group, has been observed. Compounds having a carbonyl group at position 6 of the triazine ring fragment in the source by elimination of NO followed by HF or CO. The decomposition pathways occurring due to CID experiments have shown interesting features d…
Crystal structures of allyltriphenyl-phosphonium halogenocuprates(I)
2013
Alternating-current electrochemical synthesis is used to obtain for the first time halogenocuprates of an allyl derivative of phosphonium of the composition (CH2=CHCH2(C6H5)3P)CuX2 (X = Br (I), Cl (II)). Compound I crystallizes in the space group P21, a = 9.6341(3) A, b = 12.4167(4) A, c = 9.9618(4) A, β = 117.484(5)°, Z = 2. Compound II crystallizes in the space group P21/n, a = 9.9725(5) A, b = 15.4586(8) A, c = 13.7557(5) A, β = 90.429(4)°, Z = 4. In the structures of I and II quasilinear CuX 2 − anions are held by C-H…X hydrogen bonds inside a framework formed by the stacking of phenyl groups from CH2=CHCH2(C6P5)3P+ cations. Allyl groups are not involved in coordination with copper(I) a…
Should the government pay more to public sector employees? Impact of subjective, stereotypicalwage and core self-evaluations on job satisfaction and …
2018
There are many stereotypes about work in public sector. It is supposedly more stable, less hectic but in the same time offers smaller wages in comparison to a work in private sector. But does it provide more satisfaction to employees? The current study compares work satisfaction (Warr, Cook, & Wall, 1979) and subjective Well-being (Diener, Emmons, Larsen, & Griffin, 1985) as dependent on subjective and objective wage evaluations (Brown, Gardner, Oswald, & Qian, 2008; Walczak, 2017) and Core Self-Evaluations (Judge, Locke, & Durham, 1997; Walczak & Derbis, 2015). On a sample of N=625 employees (of which 18%; n=118 were employed in public sector) an impact of subjective (rather than objective…