Nitric oxide, cell multiplication, and cell survival

Arrest of cell division is crucial for cells to enter a program of terminal differentiation. In the developing organ or a differentiating tissue, growth arrest defines roughly the size of the cellular population that is further committed to become a domain of differentiated cells. Eventually, the balance between the number of cell divisions and the extent of subsequent programmed cell death determines the final size of a domain, a tissue, or an organ (for review, see Bryant and Simpson 1984; Raff 1992, 1996). Mitogenesis, cytostasis, and survival of neuronal cells can be induced and maintained by the same or by different growth or trophic factors. The signaling pathways that coordinate proliferation, growth arrest, and survival of cells and groups of cells in developing organisms are not known, but they probably involve as yet undetermined inter- and intra-cellular second messenger molecules

Excitations in the Halo Nucleus He-6 Following The Li-7(gamma,p)He-6 Reaction

A broad excited state was observed in 6-He with energy E_x = 5 +/- 1 MeV and width Gamma = 3 +/- 1 MeV, following the reaction Li-7(gamma,p)He-6. The state is consistent with a number of broad resonances predicted by recent cluster model calculations. The well-established reaction mechanism, combined with a simple and transparent analysis procedure confers considerable validity to this observation.Comment: 3 pages of LaTeX, 3 figures in PostScript, approved for publication in Phys. Rev. C, August, 200

Sub-200-kHz single soliton generation in a long ring Er-fiber laser with strict polarization control by using twisted fiber

In the present work we demonstrate a novel single-soliton ultra-low pulse repetition frequency passively modelocked erbium-doped fiber laser. We mitigate the residual linear birefringence of fiber by fiber twist to achieve a strict control of polarization. For mode-locking the nonlinear polarization rotation (NPR) was used. Special technique was applied to reduce the overdriving of NPR that allows the generation of single soliton in ultra-long cavity. The strict control of polarization yields a stable relation between the polarization state of the pulses propagating in the cavity and the regimes of generation. A 192.12-kHz train of soliton pulses was obtained with pulse duration of 4.7 ps at 1560.1 nm, the average power was 29 μW and the estimated peak power was ̴30.8 W with an energy of 150.9 pJ

Tunable dual-wavelength operation of an all- fiber thulium-doped fiber laser based on tunable fiber Bragg gratings

Tunable dual-wavelength emission of a Tm-doped fiber laser based on two fiber Bragg gratings(FBGs) is experimentally demonstrated. By using two FBGs with central wavelengths at 2069.30 and 2069.44 nm, stable dual-wavelength laser generation in the 2 μm wavelength region is achieved by adjusting the differential loss of the two wavelengths in the laser cavity. Strain applied on the FBG allows independent tuning of the simultaneously generated wavelengths with separation between the laser lines in a range from 0.54 to 9 nm. The laser has output power fluctuations less than 0.093% for an output power of 77.3 mW

Long cavity ring fiber mode-locked laser with decreased net value of nonlinear polarization rotation

We investigate a new configuration of a mode-locked fiber laser by using a nonlinear polarization rotation-based design to generate soliton pulses with low repetition rate. Unlike with previously reported configurations, we introduce a Faraday mirror after the first half of the cavity length to counteract the nonlinear polarization rotation effects. The total cavity length is 437 m including a 400-m long twisted SMF-28 fiber. The fiber was twisted to cancel the linear birefringence and to ensure that the polarization ellipticity is not altered as the pulse travels along the fiber. The strict control of polarization yields a stable relation between the polarization state of the pulses propagating in the cavity and the regimes of generation. Depending on the polarization state we observed three different emission regimes, the single soliton regime (SR), conventional noise-like pulses (NLP) and noise-like square-waveform pulse (NLSWP). In the SR, a 467.2 kHz train of solitons was obtained with pulse duration of 2.9 ps at 1558.7 nm

ЭКСПЕРИМЕНТАЛЬНОЕ СРАВНЕНИЕ АЭРОЗОЛЬНОГО МЕТОДА ПРИ ДЕЗИНФЕКЦИИ ВОЗДУХА И ПОВЕРХНОСТЕЙ, КОНТАМИНИРОВАННЫХ M. TUBERCULOSIS

The objective of the study: to analyze efficiency of an aerosol method of M. tuberculosis deactivation in the air and on surfaces versus the conventional methods of the disinfectants' application.Subjects and Methods. The article describes the evaluation of efficiency of the aerosol method of M. tuberculosis, H37Rv strain, deactivation on surfaces (tested objects made of linoleum) and in the air using the disinfectant of Green Dez based on chlorine dioxide versus deactivation through wiping and irrigation.The efficiency of disinfectant was tested by the device of 099С А4224 manufactured by Glas-Col, USA, using the air sampler of PU-1B, Russia.The Mobile Hygienic Center (MNC), Russia, was used for application of the disinfectant, wiping and irrigation was done using the disperser of Avtomaks AO-2, Russia.The bacterial aerosol was generated in the Glass-Col chamber with the concentration 5 ± 2.5 × 102 CFU/cm3, by spraying the suspension of M. tuberculosis, H37Rv strain. After that, the disinfectant spray was supplied to the chamber, where linoleum objects were placed horizontally on a variety of surfaces. In order to evaluate efficiency of surface treatment by wiping, the test objects were wiped with a tissue, soaked with the solution of Green Dez, based on consumption of 100-150 ml/m2. In 15, 30 and 60 minutes, the samples of inactivated M. tuberculosis aerosol were collected using an aspirator, chambers with test objects were closed and placed in the vent hood. To monitor efficiency of disinfection of the test object surfaces, the rinse blanks were done by wiping the surface with a sterile gauze wad, soaked with 0.5% of sodium thiosulfate solution.The samples of deactivated aerosol and rinse blanks from the surfaces of test objects were put into Petri dishes with Middlebrook 7H11 medium. The cultures were incubated in the thermostat at the temperature of 37 ± 1° C for 10-21 days, and the number of colonies was counted.Sterile water was used instead of disinfectant for control tests treating the tests objects contaminated in the same manner.Results. The good disinfection properties of Green Dez aerosol were proved during the simulation of M. tuberculosis, H37Rv strain, disinfection on the surfaces and in the air.The efficiency analysis of the aerosol method of disinfection proved the reduction of disinfectant consumption by 4-5 times versus wiping and irrigation, due to this the aerosol treatment can be regarded as a safer and more environmentally friendly method.The finely dispersed disinfectant aerosol, produced by MNC, effectively decontaminated the whole space, including the remote and hard-to-reach places. Full automation of disinfection implies no human presence providing high safety of disinfection. Цель исследования: анализ эффективности аэрозольного метода дезактивации возбудителя туберкулеза в воздухе и на поверхностях в сравнении с традиционными методами нанесения дезинфектанта.Материалы и методы. Проведена оценка эффективности аэрозольного метода дезактивации возбудителя туберкулеза (штамм М. tuberculosis H37Rv) на поверхностях (тест-объекты из линолеума) и в воздухе дезинфицирующим средством Green Dez на основе диоксида хлора в сравнении с обработкой методами протирания и орошения.Оценку эффективности действия ДС проводили в установке модели 099С А4224 фирмы Glas-Col, США, при помощи устройства для отбора проб воздуха ПУ-1Б, Россия.Для нанесения дезинфектанта использовали распыление с помощью Мобильного гигиенического центра (МГЦ, Россия), протирание салфеткой и орошение с применением распылителя «Автомакс АО-2», Россия.В камере Glas-Col создавали бактериальный аэрозоль с концентрацией 5 ± 2,5 × 102 КОЕ/см3, распыляя суспензию штамма М. tuberculosis H37Rv. Далее в камеру подавался распыленный дезинфектант, там же находились тест-объекты из линолеума горизонтально на различных поверхностях. В опытах по оценке эффективности обработки поверхностей методом протирания тест-объекты протирали салфеткой, смоченной в растворе Green Dez, исходя из расхода 100-150 мл/м2. Спустя 15, 30 и 60 мин проводили отбор проб инактивированного аэрозоля МБТ при помощи аспиратора, закрывали емкости с тест-объектами и переносили их в вытяжной шкаф. Для контроля эффективности обеззараживания поверхностей с тест-объектов делали смывы путем тщательного протирания поверхности стерильной марлевой салфеткой, увлажненной 0,5%-ным раствором тиосульфата натрия.Пробы инактивированного аэрозоля и смывы с поверхности тест-объектов вносили на чашки Петри с питательной средой Middlebrook 7H11. Посевы инкубировали в термостате при температуре 37 ± 1°C в течение 10-21 сут, затем подсчитывали число колоний. В контрольных опытах для обработки аналогично контаминированных тест-объектов вместо раствора ДС использовали стерильную воду.Результаты. Установлена высокая дезинфицирующая способность аэрозоля средства GreenDez при моделировании процесса инактивации М. tuberculosis H37Rv как на поверхностях, так и в воздушной среде.Анализ эффективности аэрозольного метода обработки позволил определить, что расход дезинфицирующих средств уменьшается в 4-5 раз в сравнении с протиранием и орошением, вследствие чего аэрозольную обработку можно отнести к более экономичным и экологичным методам.Мелкодисперсный аэрозоль ДС, производимый установкой МГЦ, эффективно обеззараживает все помещение, в том числе труднодоступные и удаленные места. Полная автоматизация процесса исключает присутствие человека, позволяя обеспечить высокую безопасность проведения дезинфекционных мероприятий.

Nonlinear stability analysis of the Emden-Fowler equation

In this paper we qualitatively study radial solutions of the semilinear elliptic equation $\Delta u + u^n = 0$ with $u(0)=1$ and $u'(0)=0$ on the positive real line, called the Emden-Fowler or Lane-Emden equation. This equation is of great importance in Newtonian astrophysics and the constant $n$ is called the polytropic index. By introducing a set of new variables, the Emden-Fowler equation can be written as an autonomous system of two ordinary differential equations which can be analyzed using linear and nonlinear stability analysis. We perform the study of stability by using linear stability analysis, the Jacobi stability analysis (Kosambi-Cartan-Chern theory) and the Lyapunov function method. Depending on the values of $n$ these different methods yield different results. We identify a parameter range for $n$ where all three methods imply stability.Comment: 12 pages; new reference added; 3 new references added; fully revised versio

ALL-1/MLL1, a homologue of Drosophila TRITHORAX, modifies chromatin and is directly involved in infant acute leukaemia

Rearrangements of the ALL-1/MLL1 gene underlie the majority of infant acute leukaemias, as well as of therapy-related leukaemias developing in cancer patients treated with inhibitors of topoisomerase II, such as VP16 and doxorubicin. The rearrangements fuse ALL-1 to any of \u3e50 partner genes or to itself. Here, we describe the unique features of ALL-1-associated leukaemias, and recent progress in understanding molecular mechanisms involved in the activity of the ALL-1 protein and of its Drosophila homologue TRITHORAX