Dynamics of myelin content decrease in the rat stroke model

The majority of studies were usually focused on neuronal death after brain ischemia; however, stroke affects all cell types including oligodendrocytes that form myelin sheath in the CNS. Our study is focused on the changes of myelin content in the ischemic core and neighbor structures in early terms (1, 3 and 10 days) after stroke. Stroke was modeled with middle cerebral artery occlusion (MCAo) in 15 male rats that were divided into three groups by time points after operation. Brain sections were histologically stained with Luxol Fast Blue (LFB) for myelin quantification. The significant demyelination was found in the ischemic core, corpus callosum, anterior commissure, whereas myelin content was increased in caudoputamen, internal capsule and piriform cortex compared with the contralateral hemisphere. The motor cortex showed a significant increase of myelin content on the 1st day and a significant decrease on the 3rd and 10th days after MCAo. These results suggest that stroke influences myelination not only in the ischemic core but also in distant structures

Passive mode locking of a Tm,Ho:KY(WO4)(2) laser around 2 μm

We report the first demonstration, to our knowledge, of passive mode locking in a Tm3+, Ho3+-codoped KYWO42 laser operating in the 2000-2060 nm spectral region. An InGaAsSb-based quantum well semiconductor saturable absorber mirror is used for the initiation and stabilization of the ultrashort pulse generation. Pulses as short as 3.3 ps were generated at 2057 nm with average output powers up to 315 mW at a pulse repetition frequency of 132 MHz for 1.15 W of absorbed pump power at 802 nm from a Ti:sapphire laser

Частица со спином 1/2 с аномальным магнитным и электрическим дипольным моментами

It is Petras who first developed the P-symmetric theory for a spin 1/2 particle with an anomalous magnetic moment within the general Gel’fand – Yaglom approach. Recently, similarly it was introduced a P-asymmetric wave equation for a spin 1/2 particle which describes a particle with an electric dipole moment. In this paper, we study solutions of the equation for the P-asymmetric particle in presence of external magnetic fields. It turns out that the energy spectra are the same for P-asymmetric and P-symmetric particles. To clarify this coincidence, we demonstrate that there exists a simple transformation relating these two models, by which one wave equation can be reduced to the form of the other. Meanwhile, expressions for wave functions and P-reflection operators are different in these two theories. We extend this approach to the model in which both P-symmetric and P-asymmetric sectors are presented. The main result is the same, namely, there exists a simple, more general as compared with the mentioned above transformation relating the P-symmetric model and the model with two sectors, and expressions for wave functions and P-reflection operators are different in these two bases. We demonstrate that in the presence of an external uniform magnetic field, the energy spectra in the model with two sectors coincide with those in the P-symmetric theory. Thus, we develop a general theory for the P-asymmetric model and the model with two sectors within the Petras approach.P-симметричная теория частицы с аномальным магнитным моментом была развита Петрашем в рамках общего подхода Гельфанда – Яглома. Недавно в рамках аналогичного подхода было введено P-асимметричное волновое уравнение для частицы со спином 1/2, которое описывает частицу с электрическим дипольным моментом. В настоящей работе исследуются решения уравнения для P-асимметричной частицы в присутствии внешних магнитных полей. Оказалось, что энергетический спектр P-асимметричной частицы такой же, как у P-симметричной частицы. Для обоснования этого совпадения показано, что существует простое преобразование, с помощью которого одно волновое уравнение может быть приведено к виду другого, при этом выражения для волновых функций и операторов P-отражения различны в этих двух теориях. Данный подход обобщен на модель, в которой представлены оба сектора: P-симметричный и P-асимметричный. Основной результат оказался тем же: существует простое преобразование, более общее, чем указанное выше, связывающее P-симметричную модель и модель с двумя секторами, выражения для волновых функций и операторов P-отражения различны в этих двух базисах. Показано, что при наличии внешнего однородного магнитного поля энергетические спектры в модели с двумя секторами совпадают с таковыми в P-симметричной теории. Таким образом, развита общая теория P-асимметричной модели и модели с двумя секторами в рамках подхода Петраша

Increased Sensitivity to Possible Muonium to Antimuonium Conversion

A new experimental search for muonium-antimuonium conversion was conducted at the Paul Scherrer Institute, Villigen, Switzerland. The preliminary analysis yielded one event fulfilling all required criteria at an expected background of 1.7(2) events due to accidental coincidences. An upper limit for the conversion probability in 0.1 T magnetic field is extracted as $8 \cdot 10^{-11}$ (90% CL).Comment: 2 figure

Spin 1/2 particle with anomalous magnetic and electric dipole moments theories with one and three mass parameters

In this paper, we study solutions of the equation for the P-asymmetric particle with spin ½ in presence of external magnetic fields. It turns out that energy spectra are the same for P-asymmetric and P-symmetric particles

Частица со спином 1/2 с аномальным магнитным и электрическим дипольным моментами

It is Petras who first developed the P-symmetric theory for a spin 1/2 particle with an anomalous magnetic moment within the general Gel’fand – Yaglom approach. Recently, similarly it was introduced a P-asymmetric wave equation for a spin 1/2 particle which describes a particle with an electric dipole moment. In this paper, we study solutions of the equation for the P-asymmetric particle in presence of external magnetic fields. It turns out that the energy spectra are the same for P-asymmetric and P-symmetric particles. To clarify this coincidence, we demonstrate that there exists a simple transformation relating these two models, by which one wave equation can be reduced to the form of the other. Meanwhile, expressions for wave functions and P-reflection operators are different in these two theories. We extend this approach to the model in which both P-symmetric and P-asymmetric sectors are presented. The main result is the same, namely, there exists a simple, more general as compared with the mentioned above transformation relating the P-symmetric model and the model with two sectors, and expressions for wave functions and P-reflection operators are different in these two bases. We demonstrate that in the presence of an external uniform magnetic field, the energy spectra in the model with two sectors coincide with those in the P-symmetric theory. Thus, we develop a general theory for the P-asymmetric model and the model with two sectors within the Petras approach