Дисперсионные элементы зеркального спектрометра на диапазон 7-30 nm

Chromosomes without a 30-nm chromatin fiber

How is a long strand of genomic DNA packaged into a mitotic chromosome or nucleus? The nucleosome fiber (beads-on-a-string), in which DNA is wrapped around core histones, has long been assumed to be folded into a 30-nm chromatin fiber, and a further helically folded larger fiber. However, when frozen hydrated human mitotic cells were observed using cryoelectron microscopy, no higher-order struc...

Chromatin without the 30-nm fiber

Magnetically assembled 30 nm diameter nickel nanowire with ferromagnetic electrodes.

Facile, cost-effective, and manufacturable techniques to create single-nanowire based devices with good electrical interconnects is demonstrated by combining template directed electrodeposition, magnetic assembly, and a post-annealing in a reducing environment. Nickel nanowires with a diameter of approximately 30 nm were electrodeposited from low-stress nickel sulfamate baths at room temperatur...

Internal structure of the 30 nm chromatin fiber.

In the presence of 1.7 mM Mg2+, the diameter of the circular structures produced by small chromatin fragments isolated from chicken erythrocytes remains essentially unchanged when the number of nucleosomes in these fragments increases from 10 to 36. In contrast, the results obtained in unidirectional shadowing experiments show that under the same conditions the height of the chromatin fragments...

Potential Function Describing the Folding of the 30 nm Fiber

Most of the DNA in a eucaryotic cell nucleus is accurately described as an extremely long thin fiber which is smoothly folded by histones into a thicker fiber called the 30 nm fiber. For the DNA to remain biologically functional, the 30 nm fiber must be only marginally stable. Therefore, we assume that the 30 nm fiber has fluidlike properties under physiologic conditions. It does not possess a ...