52 research outputs found
THE BEAM ENVELOPE CONTROL IN SC LINAC FOR THE PROTON RADIOTHERAPY
Abstract Proton cancer therapy is conventionally based on normal conducting synchrotrons and cyclotrons. The high electrical power consumption and especial devices necessary to energy variation are main problems of such facilities. Superconducting linacs based on short identical independently phased cavities have a seriously progress and it's development allow to propose their using for medical application. High accelerating gradient and small capacity losses nearly 10 -4 W/m are main advantages in advance of normal conducting facilities, the energy variation can be realized by means of RF field amplitude and phase variation in a number of cavities. Besides linac structures are lack of unwieldy magnetic system, simplicity of input and output of particles and high current densities. The parameters choose and the optimization for SC linac structure with energy up to 240 MeV and envelope control will discuss in this paper. The simulation was done using BEAMDULAC-SCL cod
CONVENIENT SYNTHESIS OF NEW 1,10-PHENANTHROLINE LIGANDS AND THE DEPENDENCE OF THEIR CONFORMATIONS ON COMPLEXATION
Derivatives of phenanthroline are widely used in analytical and inorganic chemistry as ligands for complexation of heavy metals. In particular, they bind cations of heavy metals in the processes of the industrial wastewater purification
CONVENIENT SYNTHESIS OF 1,3-DITHIOLANE-2-THIONES
Trithiocarbonates (1,3-dithiolane-2-thiones, 2) are used as building blocks in synthesis of versatile ligands and polymers. They also possess radioprotective and insecticidal activities
CONVENIENT SYNTHESIS OF NEW 1,10-PHENANTHROLINE LIGANDS AND THE DEPENDENCE OF THEIR CONFORMATIONS ON COMPLEXATION
Derivatives of phenanthroline are widely used in analytical and inorganic chemistry as ligands for complexation of heavy metals. In particular, they bind cations of heavy metals in the processes of the industrial wastewater purification
CONVENIENT SYNTHESIS OF 1,3-DITHIOLANE-2-THIONES
Trithiocarbonates (1,3-dithiolane-2-thiones, 2) are used as building blocks in synthesis of versatile ligands and polymers. They also possess radioprotective and insecticidal activities
Thio-β-D-glucosides: Synthesis and evaluation as glycosidase inhibitors and activators
Novel structurally simple 1-thio-β-D-glucopyranosides were synthesized and tested as potential inhibitors towards several fungal glycosidases from Aspergillus oryzae and Penicillium canescens. Significant selective inhibition was observed for α- and β-glucosidases, while the same compounds produced a weak to moderate activation of α- and β-galactosidases
BEAM DYNAMICS SIMULATION FOR THE 1 GeV HIGH POWER PROTON LINAC
Abstract The design of high energy and high power proton linacs for accelerating driven systems (ADS) is one of the accelerator technology frontiers. Such linacs are under developing in EU, Japan, PRC but not discussed in Russia previous ten years. The driver linac and the breeder conceptual designs were funded by the Ministry of Science and Education of Russian Federation in 2013. The 2 MeV RFQ linac was proposed as the first accelerating section. A number of RF focusing sections types (by RF crossed lenses, modified electrode profile RFQ, axi-symmetrical RF focusing) were discussed for medium energies. The conventional modular scheme linac based on spoke-cavities and 5-cell elliptical cavities was designed for higher energies. The results of beam dynamics simulation in this linac will present
The Effect of Cationic Polylysine on the Release of an Encapsulated Substance from pH-Sensitive Anionic Liposomes
The formation of complexes from anionic liposomes with a pH-sensitive molecular switch (flipid) and a cationic polypeptide (polylysine) embedded in the membrane with a degree of polymerization of 90, 660, and 1360 was investigated. Liposomes in the complex retain their integrity in a buffer solution with a pH of 7; The resulting complexes are resistant to dissociation in a physiological solution containing 0.15 M NaCl. Lowering the pH of the solution to 5 causes the formation of defects in the lipid bilayer by changing the conformation of the flipid, which leads to the release of the encapsulated substance from the liposomes into the surrounding solution. In this case, complexation increases both the rate of release of the encapsulated substance and the amount of the substance moving from the liposomes to the external solution. The results obtained are of interest for encapsulation and controlled drug delivery
Arylsulfanyl groups – suitable side chains for 5-substituted 1,10- phenanthroline metal complexes as G4 ligands and telomerase inhibitors
Telomerase is pivotal to the survival of 80-90% tumor cells where its activity overcomes the Hayflick limit related to cellular aging, but it is virtually absent in normal somatic cells. Such difference in presence has made it a promising anticancer target in recent years. Inducing G- quadruplex formation in G-rich telomeric DNA regions inhibits telomerase activity because telomerase only efficiently binds to DNA single strands. Formation of G-quadruplexes occurs in the presence of monovalent cations such as Na+ and K+under physiological conditions, which could be further enhanced by small molecules known as G4 ligands. A conventional G4 ligand has a large aromatic surface area that maximizes - stacking interaction with the end G-quartet(s) in a G-quadruplex. Ligand side chains also play an important role in inducing G-quadruplex formation and inhibiting human telomerase activity. Phenanthroline derivatives are examples of G4 ligands that form a large aromatic surface by coordinating with metal ions and preferentially bind to G-quadruplex over duplex DNA. Most of the phenanthroline-based G4 ligands are modified at the 4 position or inner arc (2 and/or 9 positions). To the best of our knowledge, the effect of side chains of phenanthrolines has not been extensively studied
Arylsulfanyl groups – suitable side chains for 5-substituted 1,10- phenanthroline metal complexes as G4 ligands and telomerase inhibitors
Telomerase is pivotal to the survival of 80-90% tumor cells where its activity overcomes the Hayflick limit related to cellular aging, but it is virtually absent in normal somatic cells. Such difference in presence has made it a promising anticancer target in recent years. Inducing G- quadruplex formation in G-rich telomeric DNA regions inhibits telomerase activity because telomerase only efficiently binds to DNA single strands. Formation of G-quadruplexes occurs in the presence of monovalent cations such as Na+ and K+under physiological conditions, which could be further enhanced by small molecules known as G4 ligands. A conventional G4 ligand has a large aromatic surface area that maximizes - stacking interaction with the end G-quartet(s) in a G-quadruplex. Ligand side chains also play an important role in inducing G-quadruplex formation and inhibiting human telomerase activity. Phenanthroline derivatives are examples of G4 ligands that form a large aromatic surface by coordinating with metal ions and preferentially bind to G-quadruplex over duplex DNA. Most of the phenanthroline-based G4 ligands are modified at the 4 position or inner arc (2 and/or 9 positions). To the best of our knowledge, the effect of side chains of phenanthrolines has not been extensively studied
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