A novel long non-coding natural antisense RNA is a negative regulator of Nos1 gene expression

Long non-coding natural antisense transcripts (NATs) are widespread in eukaryotic species. Although recent studies indicate that long NATs are engaged in the regulation of gene expression, the precise functional roles of the vast majority of them are unknown. Here we report that a long NAT (Mm-antiNos1 RNA) complementary to mRNA encoding the neuronal isoform of nitric oxide synthase (Nos1) is expressed in the mouse brain and is transcribed from the non-template strand of the Nos1 locus. Nos1 produces nitric oxide (NO), a major signaling molecule in the CNS implicated in many important functions including neuronal differentiation and memory formation. We show that the newly discovered NAT negatively regulates Nos1 gene expression. Moreover, our quantitative studies of the temporal expression profiles of Mm-antiNos1 RNA in the mouse brain during embryonic development and postnatal life indicate that it may be involved in the regulation of NO-dependent neurogenesis

The temporal expression profile of a Nos3-related natural antisense RNA in the brain suggests a possible role in neurogenesis

Experimental work over the past several years has revealed an unexpected abundance of long natural antisense transcripts (NATs) in eukaryotic species. In light of the proposed role of such RNA molecules in the regulation of gene expression in the brain, attention is now focused on specific examples of neuronal NATs. Of particular interest are NATs that are complementary to mRNAs encoding nitric oxide synthase (NOS), the enzyme responsible for production of the important gaseous neurotransmitter nitric oxide (NO). Here we study the temporal expression profile of murine Nos3as NAT in the brain. Notably, Nos3as NAT is known to act as a negative regulator of Nos3 gene expression. The results of our quantitative analysis reveal differential expression of Nos3as NAT during embryonic and post-embryonic stages of development of the brain. Also, they show that the low levels of Nos3as NAT coincides with active neurogenesis. In addition we report on an inverse correlation between the relative expression level of Nos3as NAT and the level of Nos3 protein. Thus our data raise the hypothesis that the Nos3as NAT regulates neurogenesis through suppression of Nos3 gene activity. This idea is further supported by experiments conducted on the olfactory bulbs and cultured neuroblastoma cells

Controllable direction of liquid jets generated by thermocavitation within a droplet.

A high-velocity fluid stream ejected from an orifice or nozzle is a common mechanism to produce liquid jets in inkjet printers or to produce sprays among other applications. In the present research, we show the generation of liquid jets of controllable direction produced within a sessile water droplet by thermocavitation. The jets are driven by an acoustic shock wave emitted by the collapse of a hemispherical vapor bubble at the liquid-solid/substrate interface. The generated shock wave is reflected at the liquid-air interface due to acoustic impedance mismatch generating multiple reflections inside the droplet. During each reflection, a force is exerted on the interface driving the jets. Depending on the position of the generation of the bubble within the droplet, the mechanical energy of the shock wave is focused on different regions at the liquid-air interface, ejecting cylindrical liquid jets at different angles. The ejected jet angle dependence is explained by a simple ray tracing model of the propagation of the acoustic shock wave inside the droplet

ОБРАБОТКА ЭЛЛИПТИЧЕСКИ ПОЛЯРИЗОВАННОГО СИГНАЛА В РАДИОЛОКАЦИОННЫХ СТАНЦИЯХ С ЦИФРОВЫМ СИНТЕЗИРОВАНИЕМ АПЕРТУРЫ АНТЕННЫ

The processing of the elliptically polarized reflected signal in the Earth remote sensing systems makes it possible to obtain additional advantages when solving problems of recognition of the observable objects on the ground and under the ground. Full polarization reception implemented in radar stations with digital synthesis of the antenna aperture when remote sensing of the Earth increases the information content of such radars (the radar image of the investigated surface is detailed, the contrast of objects in the field of view is improved, and various negative effects of the image are minimized). The paper considers the quadrature processing of the reflected elliptically polarized signal in radar stations with digital synthesis of the antenna aperture in the mode of lateral survey of the terrestrial (water) surface. The processing of the reflected signal using the methods of radio polarimetry opens new possibilities for such radars while solving problems of remote sensing of the surface and recognition of radar targets. In addition, radar stations with digital synthesis of the antenna aperture with processing of an elliptically polarized signal have a higher interference immunity compared to radars, where a linearly polarized signal is processed. In the article, mathematical modeling is performed in the part of demodulation of the in-phase and quadrature components of the trajectory signal when the geometric parameters of the polarization ellipse change. The obtained analytical expressions allow estimating the influence of the geometric parameters of the polarization ellipse on the trajectory signal being processed. It is analytically confirmed that the angle of ellipticity affects the energy characteristics, and the orientation angle of the polarization ellipse introduces an additional phase shift in the characteristics of the trajectory signal being processed. Not taking into account these nuances while designing digital units and systems of such radars can lead to the loss of all the benefits of processing an elliptically polarized signal. The paper presents a structural scheme of the polarization radar station with digital synthesis of the antenna aperture.Обработка эллиптически поляризованного отраженного сигнала в системах дистанционного зондирования Земли позволяет получать дополнительные преимущества при решении задач распознавания наблюдаемых объектов на земле и под землей. Полный поляризационный прием, реализованный в радиолокационных станциях с цифровым синтезированием апертуры антенны, при дистанционном зондировании Земли повышает информативность таких радиолокаторов (детализируется радиолокационное изображение исследуемой поверхности, подчеркивается контрастность объектов, находящихся в зоне обзора, минимизируются различные негативные эффекты изображения). В статье рассматривается квадратурная обработка отраженного эллиптически поляризованного сигнала в радиолокационных станциях с цифровым синтезированием апертуры антенны в режиме бокового обзора земной (водной) поверхности. Обработка отраженного сигнала с использованием методов радиополяриметрии открывает новые возможности перед такими радиолокаторами при решении задач дистанционного зондирования поверхности и распознавания радиолокационных целей. Кроме того, радиолокационные станции с цифровым синтезированием апертуры антенны с обработкой эллиптически поляризованного сигнала имеют более высокую помехоустойчивость по сравнению с радиолокаторами, где обрабатывается линейнополяризованный сигнал. В статье производится математическое моделирование в части демодуляции синфазной и квадратурной составляющих траекторного сигнала при изменении геометрических параметров эллипса поляризации. Полученные аналитические выражения позволяют оценить влияние геометрических параметров эллипса поляризации на обрабатываемый траекторный сигнал. Аналитически подтверждается, что угол эллиптичности оказывает влияние на энергетические характеристики, а угол ориентации эллипса поляризации вносит дополнительный фазовый сдвиг в характеристики обрабатываемого траекторного сигнала. Неучет этих нюансов при проектировании цифровых блоков и систем таких радиолокаторов может привести к потере всех преимуществ обработки эллиптически поляризованного сигнала. В статье приводится структурная схема поляризационной радиолокационной станции с цифровым синтезированием апертуры антенны

Electron-phonon scattering at the intersection of two Landau levels

We predict a double-resonant feature in the magnetic field dependence of the phonon-mediated longitudinal conductivity $\sigma_{xx}$ of a two-subband quasi-two-dimensional electron system in a quantizing magnetic field. The two sharp peaks in $\sigma_{xx}$ appear when the energy separation between two Landau levels belonging to different size-quantization subbands is favorable for acoustic-phonon transitions. One-phonon and two-phonon mechanisms of electron conductivity are calculated and mutually compared. The phonon-mediated interaction between the intersecting Landau levels is considered and no avoided crossing is found at thermal equilibrium.Comment: 13 pages, 8 figure