Erratum to “Minimal Surfaces in ℍ2 × ℝ”

In ?² × ? one has catenoids, helicoids and Scherk-type surfaces. A Jenkins-Serrin type theorem holds here. Moreover there exist complete minimal graphs in ?² with arbitrary continuous asymptotic values. Finally, a graph on a domain of ?² cannot have an isolated singularity.     

Lanthanum zirconate nanoparticles and ceramics produced using a nitrate-modified alkoxide synthesis route

Fine lanthanum zirconate powder was prepared by thermally decomposing a nitrate-alkoxide-based precursor derived from dehydrated lanthanum nitrate, zirconium n-butoxide and 2-methoxyethanol. Upon heating, the decomposition of the organic groups was promoted by the nitrate groups, yielding a porous powder that crystallized into a pyrochlore phase at 800 °C. The powder that was heat treated at 900 °C for 1 h was composed of friable agglomerates of approximately 60-nm-sized nanoparticles. The ceramics obtained from the powder heat treated at 900 °C and milled for 30 min reached a relative density of 97.9 % after sintering at 1,400 °C for 10 h, which is at least 100 °C lower than the typically reported temperatures for this material.     

Vicarious Nucleophilic Substitution of Hydrogen and Formation of Aziridine Rings in Reactions of Benzonaphthyridines and their N-Oxides with Chloromethyl Phenyl Sulfone

 Treatment of benzonaphthyridines with chloromethyl phenyl sulfone in the presence of base led to the formation of aziridine rings annelated to the benzonaphthyridine skeleton, whereas their N-oxides underwent vicarious nucleophilic substitution of hydrogen (VNS), thus leading to the corresponding phenylsulfonylmethyl derivatives.     

Theoretical study of the structural properties of SiC(001)—Si-terminated surface and the formation of its STM images

We present theoretical study of structural and electronic properties of SiC(001)-p(2 × 1)-Si-terminated surface and the formation of its STM images. Ab initio calculations independently performed with the use of plane-wave and local-orbital basis have shown that the structure of this surface is built up by long symmetric silicon dimers, which agrees with the results of previous ab initio studies done by other authors. STM simulations show that the variation of the tunneling current along substrate surface very well reproduces the localization properties of occupied and unoccupied surface states (π, π*). We have found that the tensile stress applied along dimers axis causes the buckling of surface dimers and transfer of the charge between dimers atoms. This result suggests that the buckling of silicon surface dimers observed in LEED measurements might be caused by external stress. Presented at the X-th Symposium on Suface Physics, Prague, Czech Republic, July 11–15, 2005.     

Simulated workplace neutron fields of $$^{241}$$ Am–Be source moderated by polyethylene spheres

Journal of Radioanalytical and Nuclear Chemistry - Simulated workplace neutron fields of a $$^{241}$$ Am–Be source moderated by polyethylene spheres have been developed. The characterization...     

Development of CDK4/6 Inhibitors: A Five Years Update

The inhibition of cyclin dependent kinases 4 and 6 plays a role in aromatase inhibitor resistant metastatic breast cancer. Three dual CDK4/6 inhibitors have been approved for the breast cancer treatment that, in combination with the endocrine therapy, dramatically improved the survival outcomes both in first and later line settings. The developments of the last five years in the search for new selective CDK4/6 inhibitors with increased selectivity, treatment efficacy, and reduced adverse effects are reviewed, considering the small-molecule inhibitors and proteolysis-targeting chimeras (PROTACs) approaches, mainly pointing at structure-activity relationships, selectivity against different kinases and antiproliferative activity.     

Characterization and antidiabetic activity of salicylhydrazone Schiff base vanadium(IV) and (V) complexes

Transition Metal Chemistry - Twenty-four oxidovanadium(IV,V) complexes with tridentate Schiff base ligands based on 5-nitrosalicylaldehyde, 5-methoxysalicylaldehyde, or 5-sulfosalicylaldehyde and...     

Asymmetric Catalysis in Liquid Confinement: Probing the Performance of Novel Chiral Rhodium–Diene Complexes in Microemulsions and Conventional Solvents

The role of liquid confinement on the asymmetric Rh catalysis was studied using the 1,2-addition of phenylboroxine ( 2 ) to N-tosylimine 1 in the presence of [RhCl(C₂H₄)₂]₂ and chiral diene ligands as benchmark reaction. To get access to Rh complexes of different polarity, enantiomerically pure C₂-symmetric p-substituted 3,6-diphenylbicyclo[3.3.0]octadienes 4 and diastereomerically enriched unsymmetric norbornadienes 5 and 6 carrying either the Evans or the SuperQuat auxiliary were synthesized. A microemulsion containing the equal amounts of H₂O/KOH and toluene/reactants was formulated using the hydrophilic sugar surfactant n-octyl β-d -glucopyranoside (C₈G₁) to mediate the miscibility between the nonpolar reactants and KOH, needed to activate the Rh–diene complex. Prominent features of this organized reaction medium are its temperature insensitivity as well as the presence of water and toluene-rich compartments with a domain size of 55 Å confirmed by small-angle X-ray scattering (SAXS). Although bicyclooctadiene ligands 4 a , b , e performed equally well under homogeneous and microemulsion conditions, ligands 4 c , d gave a different chemoselectivity. For norbornadienes 5 , 6 , however, microemulsions markedly improved conversion and enantioselectivity as well as reaction rate, as was confirmed by kinetic studies using ligand 5 b .