Feasibility studies for the measurement of time-like proton electromagnetic form factors from p¯ p→ μ+μ- at P ¯ ANDA at FAIR

This paper reports on Monte Carlo simulation results for future measurements of the moduli of time-like proton electromagnetic form factors, | GE| and | GM| , using the p¯ p→ μ+μ- reaction at P ¯ ANDA (FAIR). The electromagnetic form factors are fundamental quantities parameterizing the electric and magnetic structure of hadrons. This work estimates the statistical and total accuracy with which the form factors can be measured at P ¯ ANDA , using an analysis of simulated data within the PandaRoot software framework. The most crucial background channel is p¯ p→ π+π-, due to the very similar behavior of muons and pions in the detector. The suppression factors are evaluated for this and all other relevant background channels at different values of antiproton beam momentum. The signal/background separation is based on a multivariate analysis, using the Boosted Decision Trees method. An expected background subtraction is included in this study, based on realistic angular distributions of the background contribution. Systematic uncertainties are considered and the relative total uncertainties of the form factor measurements are presented

Алгоритм динамического наблюдения пациентов с колоректальным раком в процессе комбинированного лечения

A large number of colon cancer cases are registered in Russia annually. Liver metastases are detected in half of them. Surgical treatment in combination with chemotherapy is the only effective method of treatment for such patients. Currently, 5- and 10-year life expectancy after such treatment varies within 24-58% and 17-25%, respectively. In the article, two cases demonstrate the possibilities of modern methods of combined treatment and observation of patients suffering from advanced stages of colon cancer. The protocol for case follow-up of these patients, applied in the clinic, is given. The application of this protocol makes it possible to identify new metastatic neoplasms in the liver at an early stage, which makes treatment less complicated. When interpreting the results of18F-FDG PET/CT, it is necessary to take into account that systemic chemotherapy suppresses the metabolic activity of the cells in metastatic focus. Given this, the appearance of new,18F-FDG PET/CT negative foci makes it justified to apply more active surgical tactics.Ежегодно в России регистрируется большое количество случаев рака толстой кишки, в половине из которых выявляются метастазы в печень. Хирургическое лечение в сочетании с химиотерапией является единственным эффективным методом лечения таких пациентов. В настоящее время 5- и 10-летняя продолжительность жизни после такого лечения находится в пределах 24-58 % и 17- 25 % соответственно. В статье на примере двух случаев демонстрируются возможности современных методов комбинированного лечения и наблюдения пациентов, страдающих раком толстой кишки в далеко зашедших стадиях. Приведен протокол динамического наблюдения этих больных, применяемый в клинике. Применение этого протокола позволяет выявлять появляющиеся новые метастатические образования в печени на ранней стадии, что делает их лечение менее сложным. При трактовке результатов ПЭТ КТ с 18F-ФДГ необходимо учитывать факт применения системной химиотерапии, которая подавляет метаболическую активность клеток метастатического очага. Учитывая это, появление в печени новых, негативных при ПЭТ КТ с 18F-ФДГ, очаговых образований делает оправданным применение по отношению к ним более активной хирургической тактики

Novel titanium(IV) complexes stabilized by 2-hydroxybenzyl alcohol derivatives as catalysts for UHMWPE production

A series of titanium (IV) complexes (2, 5-7) stabilized by a substituted 2-hydroxybenzyl alcohols (1, 4) – were synthesized. Structures of complexes 6-7 were determined by X-ray diffraction. Titanium atom in the tetrameric complex 6 has an octahedral environment created by chlorine atom and five oxygen atoms. The main structural feature of 7 is a centrosymmetric Ti4O6 cage which is built of two seco-norcubanes Ti4O3 sharing a common Ti2O2-face. A coordination polyhedron around the titanium atoms is the distorted octahedron, with the long Ti─μ-O and short Ti─O bonds. All resulting complexes are moderately or highly active in ethylene polymerization in the presence of {3Et2AlCl + Bu2Mg} binary co-catalyst. Resulting polymers are linear ultrahigh molecular weight polyethylenes (up to 7.9 106 g/mole). Polymers are suitable for the modern processing methods – the solvent-free solid state formation of super high-strength (tensile strength over 2.0–2.4 GPa) and high-modulus (elastic modulus up to 130 GPa) oriented film tapes. © 2018 Elsevier B.V

Novel titanium(IV) complexes stabilized by 2-hydroxybenzyl alcohol derivatives as catalysts for UHMWPE production

A series of titanium (IV) complexes (2, 5-7) stabilized by a substituted 2-hydroxybenzyl alcohols (1, 4) – were synthesized. Structures of complexes 6-7 were determined by X-ray diffraction. Titanium atom in the tetrameric complex 6 has an octahedral environment created by chlorine atom and five oxygen atoms. The main structural feature of 7 is a centrosymmetric Ti4O6 cage which is built of two seco-norcubanes Ti4O3 sharing a common Ti2O2-face. A coordination polyhedron around the titanium atoms is the distorted octahedron, with the long Ti─μ-O and short Ti─O bonds. All resulting complexes are moderately or highly active in ethylene polymerization in the presence of {3Et2AlCl + Bu2Mg} binary co-catalyst. Resulting polymers are linear ultrahigh molecular weight polyethylenes (up to 7.9 106 g/mole). Polymers are suitable for the modern processing methods – the solvent-free solid state formation of super high-strength (tensile strength over 2.0–2.4 GPa) and high-modulus (elastic modulus up to 130 GPa) oriented film tapes. © 2018 Elsevier B.V

First example of cationic titanium (III) complexes with crown ether as catalysts for ethylene polymerization

Complex cations with a vacant coordination site are considered as the most plausible catalytically active centers of metallocene and post-metallocene polymerization catalysts. For the first time we demonstrated that cationic titanium (III) complexes stabilized with crown ether can be used as pre-catalysts for ethylene polymerization. In the presence of alkyl aluminum chlorides and MgBu2 as cocatalysts, these complexes catalyze ethylene polymerization to produce Ultra High Molecular Weight Polyethylene (UHMWPE) with productivity up to 4650 kgPE/mol Ti h⋅atm and molecular weight up to 1.8·106 Da. UHMWPE powders were processed by the solid-phase method with subsequent orientation drawing into high-strength (1.4–2.1 GPa) and high-modulus (91–118 GPa) films. © 2022 Elsevier Lt

Novel titanium (IV) complexes with 1,2-diolate ligands: Synthesis, structure and catalytic activities in ultra-high molecular weight polyethylene production

A series of titanium (IV) complexes 3a-f stabilized by 1,2-diolate ligands 2 a-e have been synthesized. Structures of complexes 3d and 3e have been determined by X-ray diffraction. Titanium atoms in these complexes have a distorted square-pyramidal environment. All resulting complexes are highly active in ethylene polymerization in the presence of {3Et2AlCl + MgBu2} or {1.5Et3Al2Cl3 + MgBu2} binary co-catalysts. In the latter case, higher molecular weights of UHMWPE samples (up to 7.7 106) are achieved. Obtained polymers are suitable for the modern processing methods – the solvent-free solid state formation of super high-strength (over 2.0 – 2.8 GPa) and high-modulus (up to 145 GPa) oriented film tapes. © 201

Novel alkoxo-titanium(IV) complexes with fluorinated 2-hydroxymethylphenol derivatives as catalysts for the formation of ultra-high molecular weight polyethylene nascent reactor powders

A series of titanium (IV) complexes 3a–g stabilized by fluorinated derivatives of 2-hydroxymethylphenol have been synthesized; their composition and structure have been confirmed by NMR, IR-spectroscopy and elemental analysis. The structures of compounds 3c, 3f and 3g have been unambiguously established by X-ray diffraction study. The complexes in the presence of a binary cocatalysts {alkyl aluminum chloride + MgBu2} catalyze ethylene polymerization to afford Ultra High Molecular Weight Polyethylene (UHMWPE). The effects of substituents in the ligands on the catalytic activity and properties of the obtained polymer – molecular weight, DSC melting behavior, and morphology of nascent reactor powders have been investigated. UHMWPE samples were processed by a solid-state uniaxial deformation into high-strength (up to 2.65 GPa) and high-modulus (over 140 GPa) oriented film tapes, which indirectly indicates a low degree of entanglements between the macromolecular chains. © 2019 Elsevier B.V

Novel titanium(IV) diolate complexes with additional O-donor as precatalyst for the synthesis of ultrahigh molecular weight polyethylene with reduced entanglement density: Influence of polymerization conditions and its implications on mechanical properties

New alkoxo-titanium(IV) complexes with diolate ligand containing additional donor oxygen atom have been synthesized from readily available and scalable precursors. The structure of complex 4 was established by X-ray diffraction. Titanium atom adopts a distorted tetrahedral geometry formed by six oxygen atoms of ligands. The resulting complexes 3–4 are moderately or highly active in ethylene polymerization in the presence of {EtnAlCl3–n + Bu2Mg} binary cocatalysts. The influence of the nature of the solvent, the organoaluminum cocatalyst and the polymerization temperature on the activity of catalytic systems, and the properties of the resulting polymers were studied. The obtained polymers are linear polyethylene of ultrahigh molecular weight (up to 5.8·106 g mol−1) with a broad molecular weight distribution. The polymers are suitable for the modern methods of polymer processing—the solventless solid-state formation of super high-strength (breaking strength up to 2.8 GPa) and high-modulus (elastic modulus up to 140 GPa) oriented films and film tapes. The possibility of scaling up the synthesis of ultrahigh molecular weight polyethylene (UHMWPE) without a significant drop in the productivity of the catalytic system and polymer properties is shown. UHMWPE samples have been investigated by small-angle X-ray scattering (SAXS) methods to study the structural changes induced by solid-state drawing of nascent reactor powders. © 2021 John Wiley & Sons, Ltd