Electron detachment from negative ions in bichromatic laser field

Negative ion detachment in two-colour laser field is considered within the recent modification of Keldysh model which makes it quantitatively reliable. The general approach is illustrated by calculation of angular differential detachment rates, partial rates for particular ATD (Above Threshold Detachment) channels and total detachment rates for H$^-$ ion in bichromatic field with 1:2 frequency ratio. Both perturbative and strong field regimes are examined. Polar asymmetry and phase effects are quantitatively characterized with some new features revealed. Phase effects are found to result in a huge anisotropy factor $\sim 10^3$ in the electron angular distribution in the perturbative regime.Comment: 13 pages, 8 figures in separate files which are not incorporated in the latex file of the pape

Влияние дезоксирибонуклеиновой кислоты на расщепление белков некоторыми протеолитическими ферментами

Было исследовано влияние дезоксирибонуклеиновой кислоты на ход протеолиза яичного альбумина, сывороточного альбумина и казе ина трипсином. и химотриuсином. Установлено что ДНК тормозит протеолитический процесс при значениях рН лежащих выше изоэлектрической точки фермента и субстрата . При предварителной инкубации субстрата с ДНК наблюдалось также торможение протеолиза. Было исследовано и влияние величины соотношения ДНК/ субстрат и полимерности ДНК на процесс протеолиза. ------------------------------------------------------------------------------------------------ Utjecaj dezoksiribonukleinske kiseline na cijepanje proteina proteolitskim fermentima Budući da je poznato, da nukleinske kiseline utječu na različite fermentativne procese, u ovom je radu ispitano djelovanje dezoksiribonukleinske kiseline (DNK) na proteolitsku aktivnost tripsina. Kао supstrati upotrebljeni su različiti kristalni preparati proteina: ovalbumin, serumski albumin i kazein. Ispitivanja su vršena kod vrijednosti рН, koje su ležale iznad izoelektrične točke fermenta i supstrata. Proces proteolize praćen je s pomoću spektrofotometra SF-4 ; razlike ekstinkcija (ΔЕ) nanošene su, izražene u postocima, u grafikonima na ordinate, а vrijeme je nanošeno na apscise. Rezultati su prikazani na slikama 1, 2 i 3, iz kojih razabiremo, da nazočnost DNK inhibira proteolizu. Dalje je ispitano djelovanje prethodne inkubacije, bilo fermenta bilo suptrata s DNK, na proces proteolize. Pokazalo se, da inhibicijaa proteolize nastupa samo kod prethodne inkubacije supstrata s DNK, dakle da DNK utječe na supstrat, а ne na ferment. Ispitan je i odnos koncentracija DNK:supstrat, te je ustanovljeno, da i u velikom suvišku supstrata prema DNK dolazi do znatne inhibicije proteolize. Pokazalo se i to, da utjecaj na proces proteolize opada onako, kako opada molekularna težina DNK

Creation, doubling, and splitting, of vortices in intracavity second harmonic generation

We demonstrate generation and frequency doubling of unit charge vortices in a linear astigmatic resonator. Topological instability of the double charge harmonic vortices leads to well separated vortex cores that are shown to rotate, and become anisotropic, as the resonator is tuned across resonance

Adiabatic Theory of Electron Detachment from Negative Ions in Two-Color Laser Field

Negative ion detachment in bichromatic laser field is considered within the adiabatic theory. The latter represents a recent modification of the famous Keldysh model for multiphoton ionization which makes it quantitatively reliable. We calculate angular differential detachment rates, partial rates for particular ATD (Above Threshold Detachment) channels and total detachment rates for the Hydrogen ion in a bichromatic field with 1:3 frequency ratio and various phase differences. Reliability of the present, extremely simple approach is testified by comparison with much more elaborate earlier calculations.Comment: 22 pages, 6 Postscript figure

Testing of CP, CPT and causality violation with the light propagation in vacuum in presence of the uniform electric and magnetic fields

We have considered the structure of the fundamental symmetry violating part of the photon refractive index in vacuum in the presence of constant electric and magnetic fields. This part of the refractive index can, in principle, contain CPT symmetry breaking terms. Some of the terms violate Lorentz invariance, whereas the others violate locality and causality. Estimates of these effects, using laser experiments are considered.Comment: 12 page

Внутрибрюшинное введение клеточно-инженерной конструкции поджелудочной железы крысам с экспериментальным сахарным диабетом (предварительные результаты)

Creation of a bioartificial pancreas, including a cell-engineered construct (CEC) formed from pancreatic islets (islets of Langerhans) and a biocompatible matrix mimicking the native microenvironment of pancreatic tissue, is one of the approaches to the treatment of type 1 diabetes mellitus (T1D).Objective: to conduct preliminary in vivo studies of the functional efficacy of intraperitoneal injection of a cell-engineered pancreatic endocrine construct and a suspension of rat pancreatic islets in an experimental T1D model.Materials and methods. Tissue-specific scaffold was obtained by decellularization of human pancreatic fragments. The viability and functional activity of rat islets isolated with collagenase were determined. Experimental T1D was modeled by intraperitoneal injection of low-dose streptozotocin and incomplete Freund’s adjuvant into rats. The rats were intraperitoneally injected twice with pancreatic CEC (n = 2) or islet suspension (n = 1). Glucose levels in the blood and urine of the rats were assessed. Histological examination of organs (pancreas and kidneys) of the experimental animals was carried out.Results. After the first injection, blood glucose levels gradually decreased in all animals by more than 47% of the initial values; by follow-up day 24, the glucose level rose to the initial hyperglycemic values. After repeated administration, a 63.4% decrease in glycemic level was observed in the rats with pancreatic CEC and a 47.5% decrease in the one with islet suspension. At week 5 of the experiment, blood glucose levels gradually increased in all animals. At the same time, the glycemic index of the rat with injected pancreatic CEC was 62% lower than the glycemic index of the rat with injected islets.Conclusion. Allogeneic pancreatic islets in pancreatic CEC increase the duration of stable glycemic level in T1D rats.Создание биоискусственной поджелудочной железы (ПЖ), в том числе клеточно-инженерной конструкции (КИК), сформированной на основе островков Лангерганса и биосовместимого матрикса, имитирующего нативное микроокружение панкреатической ткани, является одним из подходов к лечению сахарного диабета I типа (СД I).Целью работы было проведение предварительных исследований in vivo функциональной эффективности внутрибрюшинного введения клеточно-инженерной конструкции эндокринного отдела поджелудочной железы и суспензии панкреатических островков крысы в экспериментальной модели СД I.Материалы и методы. Тканеспецифический матрикс получали в результате децеллюляризации фрагментов ПЖ человека. Определяли жизнеспособность и функциональную активность островков крысы, выделенных с помощью коллагеназы. Экспериментальный СД I моделировали путем внутрибрюшинного введения малых доз стрептозотоцина и неполного адъюванта Фрейнда крысам. Крысам дважды вводили внутрибрюшинно КИК ПЖ (n = 2) или суспензию островков (n = 1). Оценивали уровень глюкозы в крови и моче крыс, а также проводили гистологическое исследование органов (поджелудочная железа и почки) экспериментальных животных.Результаты. После первого введения отмечали постепенное снижение уровня глюкозы в крови всех животных более чем на 47% от исходных значений, у которых к 24 суткам наблюдения происходил подъем уровня глюкозы до исходных гипергликемических показателей. После повторного введения наблюдали снижение уровня гликемии у животных с КИК ПЖ на 63,4% и на 47,5% – у крысы с суспензией островков. Через 5 недель эксперимента происходило постепенное повышение уровня глюкозы в крови у всех животных. При этом гликемический показатель крысы с введенной КИК ПЖ был на 62% ниже показателя гликемии у крысы с введенными островками.Заключение. В предварительных экспериментах показано, что аллогенные панкреатические островки в составе КИК ПЖ увеличивают длительность стабильного уровня гликемии у крыс с СД I

Challenges in QCD matter physics --The scientific programme of the Compressed Baryonic Matter experiment at FAIR

Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (sNN= 2.7--4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials (μB> 500 MeV), effects of chiral symmetry, and the equation of state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2024, in the context of the worldwide efforts to explore high-density QCD matter