A Prebiotic Ribosylation of Pyrimidine Nucleobases Enabled by Metal Cations and Clay Minerals

We report a prebiotically relevant solution to the N1-ribosylation of pyrimidine nucleobases, a well-known challenge to the RNA world hypothesis. We found that the presence of metal cations and clay minerals enable the previously unachievable direct ribosylation of uracil. Spectroscopy and chromatography analyses confirmed the formation of ribosylated uracil. The method can be extended to the ribosylation of 2-pyrimidinone. These findings are also compatible with the metal-doped-clay model, developed by our lab for the unified route of the selection of ribose and subsequent syntheses of nucleotide and RNA.

Fabrication Methods of the Polygonal Masonry of Large Tightly Fitted Stone Blocks with Curved Surface Interfaces in Megalithic Structures of Peru

The article suggests methods that allow creating the most complicated type of polygonal masonry found in Peru. This masonry consists of large stone blocks weighing from several hundred kilograms to several tons fitted close to each other almost without a gap between complicated curved surfaces of large area. The work provides a description of techniques, which apparently were used by builders who arrived from Europe. The techniques under discussion are based on the use of a reduced clay model, 3D-pantograph and replicas. The use of a reduced clay model and a pantograph provides not only the unique appearance and high quality of masonry with large blocks, but also allows to significantly increase the productivity of the builders. As machines scaling three-dimensional objects are known since the beginning of the 18th century, the stone structures under consideration should be dated by that and later time. The remaining simpler types of polygonal masonry with smaller stones or fitted surfaces are almost flat, or stones contact with each other by a small area, or there are significant gaps between stones, are quite consistent with the well-known methods of stone processing of those and earlier years, and, therefore, they do not require any additional explanations.

A Prebiotic Ribosylation of Pyrimidine Nucleobases Promoted by Metal Cations and Clay Minerals

We report a prebiotically relevant solution to the N1-ribosylation of pyrimidine nucleobases, a well-known challenge in the RNA World hypothesis. It is found that the presence of metal cations and clay mineral enables the previously unachievable direct ribosylation of uracil, providing by far the highest yield. Spectroscopy and chromatography analyses confirmed the formation of ribosylated uracil. The method can also be extended to the ribosylation of 2-pyrimidinone. These findings are also compatible with the metal-doped-clay model developed by our lab for the unified route of the selection of ribose and subsequent syntheses of nucleotide and RNA.

Fabrication Methods of the Polygonal Masonry of Large Tightly Fitted Stone Blocks with Curved Surface Interfaces in Megalithic Structures of Peru

The article suggests methods that allow creating the most complicated type of polygonal masonry found in Peru. This masonry consists of large stone blocks weighing from several hundred kilograms to several tons fitted close to each other almost without a gap between complicated curved surfaces of large area. The work provides a description of techniques, which apparently were used by builders who arrived from Europe. The techniques under discussion are based on the use of a reduced clay model, 3D-pantograph and replicas. The use of a reduced clay model and a pantograph provides not only the unique appearance and high quality of masonry with large blocks, but also allows to significantly increase the productivity of the builders. As machines copying three-dimensional objects are known since the 18th century, the stone structures under consideration should be dated by that and later time. The remaining simpler types of polygonal masonry with smaller stones or fitted surfaces are almost flat, or stones contact with each other by a small area, or there are significant gaps between stones, are quite consistent with the well-known methods of stone processing of those and earlier years, and, therefore, they do not require any additional explanations.

Fabrication Methods of the Polygonal Masonry of Large Stone Blocks With Fitted Curved Surfaces in Megalithic Structures of Peru

The article suggests methods that allow creating the most complicated type of polygonal masonry found in Peru. This masonry consists of large stone blocks weighing from several hundred kilograms to several tons fitted close to each other almost without a gap between complicated curved surfaces of large area. The work provides a brief description of techniques, which apparently were used by builders who arrived from Europe. The techniques under discussion are based on the use of a reduced clay model, 3D-pantograph and replicas. The use of a reduced clay model and a pantograph provides not only the unique appearance and high quality of masonry with large blocks, but also allows to significantly increase the productivity of the builders. As the pantograph designed to work with three-dimensional objects has been known since the 18th century, the constructions under consideration should be dated by that and later time. The remaining simpler types of polygonal masonry with smaller stones or fitted surfaces are almost flat, or stones contact with each other by a small area, or there are significant gaps between stones, are quite consistent with the well-known methods of stone processing of those and earlier years, and, therefore, they do not require any additional explanations.