Search results for "SMIS"

Zvaigžņotā Debess: 2011, Pavasaris (211)

2011

Contents: “ZVAIGŽŅOTĀ DEBESS” FORTY YEARS AGO: A.Alksnis. XIV General Assembly of the International Astronomical Union (abridged) ; H.Strods. Jaunlaicene’s Watchmaker (abridged) ; I.Daube. At the Radioastrophysical Observatory of the Latvian Academy of Sciences (abridged). 50 YEARS SINCE GAGARIN’S SPACE FLIGHT: R.Misa. Dream about Cosmos ; A.Zalcmane. Konstantin Tsiolkovsky Astronautics Museum in Kaluga; E.Bērziņa. Outer Space in Pauls Stradins Museum of History of Medicine. NEWS: A.Alksnis. Different Faces of Whirpool Galaxy ; A.Alksnis. The Kleopatra’s Trio and other Minor Planets Groups. SPACE RESEARCH and EXPLORATION: V.Kalniņš. NASA Preparing Solar Probe Plus to Plunge into Sun's Atmos…

THE ENTERIC NERVOUS SYSTEM: NEW DEVELOPMENTS AND EMERGING CONCEPTS

2011

The enteric nervous system (ENS) is an integrative neuronal network, organized in two ganglionated plexuses, myenteric and submucosal, composed of neurons and enteric glial cells, controlling the activity of the smooth muscle of the gut, mucosal secretion and blood flow. The ENS contains as many neurons as the spinal cord, and the functional and chemical diversity of enteric neurons closely resembles that of the central nervous system. This highly integrated neural system is also referred to as the ‘brain-in-the-gut’, because of its capability to function in the absence of nerve inputs from the central nervous system.

Design of dispersion-managed fiber systems for transmitting chirp-free Gaussian pulses

2008

International audience; We present a general method to analytically design a dispersion-managed (DM) fiber system for any desired fiber (dispersion, nonlinearity and losses) and pulse (width and energy) parameters. This analytical design allows one to transmit chirp-free Gaussian pulses (for very long distances) in almost all kinds of DM fiber systems that have appeared so far in the literature, including systems with dispersion map length greater, equal or shorter with respect to the amplification period.

Size characterisation of Au nanoparticles by ICP-MS coupling techniques

2006

In modern nanotechnology the properties of nanoparticles (NPs) in different application fields is mainly dependent on their size and their size distribution. This paper aims to develop a reliable method for the size characterisation of Au NPs. Basing on the combination of two different separation techniques (liquid chromatography and gel electrophoresis), coupled on-line to inductively coupled plasma-mass spectrometry (ICP-MS), we study the separation of Au NP standards. Separations by liquid chromatography show size dependent retention behaviour with good reproducibility (RSD < 1%). The results are compared with complementary methods like dynamic light scattering (DLS) and transmission ele…

1984

Autopolymerisation de ce monomere ionique dans l'eau ou dans un solvant organique par addition d'acide protique. Suivant la concentration du monomere, il se forme un sel diyl-1,4 ou yl-4

Nitric Oxide/Cyclic Guanosine Monophosphate Signaling via Guanylyl Cyclase Isoform 1 Mediates Early Changes in Synaptic Transmission and Brain Edema …

2021

Traumatic brain injury (TBI) often induces structural damage, disruption of the blood-brain barrier (BBB), neurodegeneration, and dysfunctions of surviving neuronal networks. Nitric oxide (NO) signaling has been suggested to affect brain functions after TBI. The NO exhibits most of its biological effects by activation of the primary targets-guanylyl cyclases (NO-GCs), which exists in two isoforms (NO-GC1 and NO-GC2), and the subsequently produced cyclic guanosine monophosphate (cGMP). However, the specific function of the NO-NO-GCs-cGMP pathway in the context of brain injury is not fully understood. To investigate the specific role of the isoform NO-GC1 early after brain injuries, we perfor…

Proper synaptic vesicle formation and neuronal network activity critically rely on syndapin I

2011

Synaptic transmission relies on effective and accurate compensatory endocytosis. F-BAR proteins may serve as membrane curvature sensors and/or inducers and thereby support membrane remodelling processes; yet, their in vivo functions urgently await disclosure. We demonstrate that the F-BAR protein syndapin I is crucial for proper brain function. Syndapin I knockout (KO) mice suffer from seizures, a phenotype consistent with excessive hippocampal network activity. Loss of syndapin I causes defects in presynaptic membrane trafficking processes, which are especially evident under high-capacity retrieval conditions, accumulation of endocytic intermediates, loss of synaptic vesicle (SV) size cont…

Influence of a nonlinear coupling on the supratransmission effect in modified sine-Gordon and Klein–Gordon lattices

2017

International audience; In this paper, we analyze the conditions leading to the nonlinear supratransmission phenomenon in two different models: a modified fifth order Klein–Gordon system and a modified sine-Gordon system. The modified models considered here are those with mixed coupling, the pure linear coupling being associated with a nonlinear coupling. Especially, we numerically quantify the influence of the nonlinear coupling coefficient on the threshold amplitude which triggers the nonlinear supratransmission phenomenon. Our main result shows that, in both models, when the nonlinear coupling coefficient increases, the threshold amplitude triggering the nonlinear supratransmission pheno…

Presynaptic nitric oxide/cGMP facilitates glutamate release via hyperpolarization-activated cyclic nucleotide-gated channels in the hippocampus

2011

In hippocampal neurons, synaptic transmission is affected by a variety of modulators, including nitric oxide (NO), which was proposed as a retrograde messenger as long as two decades ago. NO signals via two NO-sensitive guanylyl cyclases (NO-GCs) (NO-GC1 and NO-GC2) and the subsequent increase in cGMP. Lack of long-term potentiation in mice deficient in either one of the two NO-GCs demonstrates the involvement of both NO-GCs in synaptic transmission. However, the physiological consequences of NO/cGMP and the cellular mechanisms involved are unknown. Here, we analyzed glutamatergic synaptic transmission, most likely reflecting glutamate release, in the hippocampal CA1 region of NO-GC knockou…

Ultrastructural myopathology in the molecular era.

2013

Electron microscopy is an essential component of myopathology, both in diagnostics and research of neuromuscular diseases. Although recently reduced in the diagnostic armamentarium, it has greatly been expanded to mouse models in research. Mostly it is descriptive, but a few additional techniques in combination with transmission electron microscopy have been employed. Foremost among them is immunoelectron microscopy, which assists in guiding molecular analysis in hereditary conditions, but may be vital in diagnostics of certain acquired entities, e.g., undulating tubules in dermatomyositis and in those congenital myopathies where genes and mutations remain to be identified, as in cylindrica…