6,950 research outputs found
Making the Best of Polymers with SulfurâNitrogen Bonds: From Sources to Innovative Materials
Polymers with sulfurânitrogen bonds have been underestimated for a long time, although the intrinsic characteristics of these polymers offer a myriad of superior properties (e.g., degradation, flame retardancy, filmâforming ability, good solubility in polar solvents, and high refractivity with small chromatic dispersions, among other things) compared to their carbon analogues. The remarkable characteristics of these polymers result from the unique chemical properties of the sulfurânitrogen bond (e.g., its polar character and the multiple valence states of sulfur), and thus open excellent perspectives for the development of innovative (bio)materials. Accordingly, this review describes the most common chemical approaches toward the efficient synthesis of these ubiquitous polymers possessing diverse sulfurânitrogen bonds, and furthermore highlights their applications in multiple fields, ranging from biomedicine to energy storage, with the aim of providing an informative perspective on challenges facing the synthesis of sulfurânitrogen polymers with desirable properties
Phase Diagram of Multilayer Magnetic Structures
Multilayer "ferromagnet-layered antiferromagnet" (Fe/Cr) structures
frustrated due to the roughness of layer interfaces are studied by numerical
modeling methods. The "thickness-roughness" phase diagrams for the case of thin
ferromagnetic film on the surface of bulk antiferromagnet and for two
ferromagnetic layers separated by an antiferromagnetic interlayer are obtained
and the order parameter distributions for all phases are found. The phase
transitions nature in such systems is considered. The range of applicability
for the "magnetic proximity model" proposed by Slonczewski is evaluated.Comment: 8 pages, 8 figure
Resonantly suppressed transmission and anomalously enhanced light absorption in ultrathin metal films
We study light diffraction in the periodically modulated ultrathin metal
films both analytically and numerically. Without modulation these films are
almost transparent. The periodicity results in the anomalous effects, such as
suppression of the transmittance accompanied by a strong enhancement of the
absorptivity and specular reflectivity, due to excitation of the surface
plasmon polaritons. These phenomena are opposite to the widely known enhanced
transparency of periodically modulated optically thick metal films. Our
theoretical analysis can be a starting point for the experimental investigation
of these intriguing phenomena.Comment: 4 pages, 5 figure
Spatial beam self-cleaning and supercontinuum generation with Yb-doped multimode graded-index fiber taper based on accelerating self-imaging and dissipative landscape
We experimentally demonstrate spatial beam self-cleaning and supercontinuum generation in a tapered Ytterbium-doped multimode optical fiber with parabolic core refractive index profile when 1064â
nm pulsed beams propagate from wider (122â
”m) into smaller (37â
”m) diameter. In the passive mode, increasing the input beam peak power above 20â
kW leads to a bell-shaped output beam profile. In the active configuration, gain from the pump laser diode permits to combine beam self-cleaning with supercontinuum generation between 520-2600â
nm. By taper cut-back, we observed that the dissipative landscape, i.e., a non-monotonic variation of the average beam power along the MMF, leads to modal transitions of self-cleaned beams along the taper length
Understanding NF-ÎșB signaling via mathematical modeling
Mammalian inflammatory signaling, for which NF-ÎșB is a principal transcription factor, is an exquisite example of how cellular signaling pathways can be regulated to produce different yet specific responses to different inflammatory insults. Mathematical models, tightly linked to experiment, have been instrumental in unraveling the forms of regulation in NF-ÎșB signaling and their underlying molecular mechanisms. Our initial model of the IÎșBâNF-ÎșB signaling module highlighted the role of negative feedback in the control of NF-ÎșB temporal dynamics and gene expression. Subsequent studies sparked by this work have helped to characterize additional feedback loops, the inputâoutput behavior of the module, crosstalk between multiple NF-ÎșB-activating pathways, and NF-ÎșB oscillations. We anticipate that computational techniques will enable further progress in the NF-ÎșB field, and the signal transduction field in general, and we discuss potential upcoming developments
The Concept of a Research Reactor of Small Power for Isotope Processing
The concept of a low-power research reactor for the production of radioisotopes is proposed, the results of calculations of the neutron-physical parameters of the core are presented, which can be used to substantiate the claimed reactor characteristics. In this article, the characteristics of the core of a research reactor of low power is substantiated, the main purpose of which is the production of radioisotope products for medical purposes. Nuclear medicine is one of the most advanced and demanded in the world of modern high-tech medicine, based on the using of atomic nucleus properties. As a rule, atoms with unstable nuclei are radionuclides. The reactor method of radionuclide production allows obtaining large quantities of radioisotope products at a relatively low price, but the reactor base is currently rather limited.
Keywords: radioisotope products, research reactors, neutron-physical characteristic
The Impact of the Functional Layer Composition of Glucose Test-Strips on the Stability of Electrochemical Response
Herein, the impact of the chemical stability of RedOx mediator ferricyanide, K3
[Fe(CN)6
]
(FC), a type of buffer solution used for bioreceptor preparation, gel composition (carboxymethylcellulose, CMC, Aerosile, AS, and alginate, ALG) on the long term stability of glucose test-strips and
their analytical performance was examined. By simple addition of ALG to the functional gel aiming
to improve its viscosity, we managed to enhance the sensitivity of conventional CMC-containing
amperometric glucose test-strips from 3.3 ”A/mM to 3.9 ”A/mM and extend their shelf life from
8 months to 1.7 years. Moreover, during the course of investigations, it was revealed that the activity
of enzyme in dependence with the used buffer did not linearly correlate with its activity in a dried
functional layer, and the entire long-term electrochemical signal of glucose test-strips was determined
by RedOx mediator FC chemical stability. The most stable and sensitive test-strips were obtained by
the screen-printing approach from a gel containing 24 mg/mL GOx prepared in citrate buffer with
pH 6, 200 mg/mL of FC and 10 mg/mL of CMC supplemented with 25 mg/mL of ALG
- âŠ