نتایج جستجو برای: silica boron
تعداد نتایج: 55027 فیلتر نتایج به سال:
As attractive analogue of graphene, boron monolayers have been theoretically predicted. However, due to electron deficiency of boron atom, synthesizing boron monolayer is very challenging in experiments. Using first-principles calculations, we explore stability and growth mechanism of various boron sheets on Cu(111) substrate. The monotonic decrease of formation energy of boron cluster B(N) wit...
In this letter we extend previously established results for nested carbon nanocones to both nested boron nitride and carbon-boron nitride nanocones. Based purely on mechanical principles and classical mathematical modelling techniques, we determine the energetically favourable structures for nested boron nitride and carbon-boron nitride nanocones. While only three apex angles for boron nitride ...
changes of major wall polysaccharides and glycoproteins of tobacco cells in response to excess boron
effects of excess concentrations of boron on major cell wall components of tobacco cells(nicotiana tabacum l. cv. burley 21) were studied. pectin, xyloglucan, hydroxyproline-richglycoproteins (extensin), and arabinogalactan proteins were characterized. results showedthat increased boron supply resulted in significant decrease in cell and cell wall dry weights.also, high concentrations of boron ...
An interesting feature of elemental boron and boron compounds is the occurrence of highly symmetric icosahedral clusters. The rich chemistry of boron is also dominated by three-dimensional cage structures. Despite its proximity to carbon in the periodic table, elemental boron clusters have been scarcely studied experimentally and their structures and chemical bonding have not been fully elucida...
Hexagonal boron nitride (hBN) is a wide bandgap van der Waals material that emerging as powerful platform for quantum optics and nanophotonics. In this work, we demonstrate whispering gallery mode silica microresonators hybridized with thin layers of hBN exhibit high intrinsic optical quality factor >7 × 105 linear absorption coefficient 9.5 cm–1. Measurements the effect thickness on Q comparis...
The application of boron neutron capture therapy to rheumatoid arthritis requires the selective delivery of the boron-10 isotope to the synovitic tissue. The use of liposomes as a boron delivery method has been explored through the measurement of the time course biodistribution of boron in rats with collagen-induced arthritis (CIA). Small unilamellar vesicles were composed of a 1:1 mixture of d...
Boron is an essential mineral nutrient for higher plant growth and development. However, excessive amounts of boron can be toxic. Here, we report on the characterization of an Arabidopsis mutant, shb1 (sensitive to high-level of boron 1), which exhibits hypersensitivity to excessive boron in roots. Positional cloning demonstrated that the shb1 mutant bears a point mutation in a gene encoding a ...
The functional properties of the Saccharomyces cerevisiae bicarbonate transporter homolog Bor1p (YNL275wp) were characterized by measuring boron (H(3)BO(3)), Na(+), and Cl(-) fluxes. Neither Na(+) nor Cl(-) appears to be a transported substrate for Bor1p. Uphill efflux of boron mediated by Bor1p was demonstrated directly by loading cells with boron and resuspending in a low-boron medium. Cells ...
For over twenty years boron has been of interest to investigators confirming the safety and essentiality of the element in humans. Fruits, vegetables, nuts, and pulses are natural sources of boron in the diet which world wide averages about 1-3 mg daily for most adults. In boron-rich regions of Turkey drinking water sources with 29 mg boron/liter are consumed without harmful effects. The Europe...
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