Search results for "clam"
showing 10 items of 454 documents
Jenis-Jenis Kima dan Kelimpahannya di Perairan Amdui Distrik Batanta Selatan Kabupaten Raja Ampat
2017
Kima merupakan salah satu jenis molusca laut yang banyak ditemukan di perairan Raja Ampat. Hewan ini dilindungi di seluruh dunia termasuk di Indonesia. Penelitian ini dilakukan pada bulan Maret-April 2014, di perairan Amdui yang memiliki ekosistem terumbu karang, dan ditetapkan 3 lokasi pengamatan yaitu: Pulau Ayem, Teluk Sawawris dan Teluk Sawros. Metode yang digunakan pada penelitian ini adalah metode observasi dengan teknik belt transek, dan bertujuan untuk mengetahui jenis dan kelimpahan kima di perairan Amdui. Kima yang ditemukan di perairan laut Kampung Amdui Kabupaten Raja Ampat yaitu 8 jenis terdiri dari T. crocea, T. maxima, T. squamosa, T .gigas, H. porcellanus, H. hippopus, T. te…
Dendrites are dispensable for basic motoneuron function but essential for fine tuning of behavior.
2014
Dendrites are highly complex 3D structures that define neuronal morphology and connectivity and are the predominant sites for synaptic input. Defects in dendritic structure are highly consistent correlates of brain diseases. However, the precise consequences of dendritic structure defects for neuronal function and behavioral performance remain unknown. Here we probe dendritic function by using genetic tools to selectively abolish dendrites in identified Drosophila wing motoneurons without affecting other neuronal properties. We find that these motoneuron dendrites are unexpectedly dispensable for synaptic targeting, qualitatively normal neuronal activity patterns during behavior, and basic …
Synthesis and first evaluation of new 18F-labelled sulfonylureas for the determination of the beta-cell status in vivo
2001
The syntheses and first in vitro evaluations for two fluoride bearing sulfonylurea derivatives are reported. Firstly, the tolbutamide derivative 1-[4-(2-[18F]fluoroethoxy)benzenesulfonyl]-3-butyl urea (2-[18F]fluoroethyl-tolbutamide) could be labeled efficiently with [18F]fluoride. Subsequently, the glibenclamid derivative N-(2-(4-(N-((cyclohexylamino)carbonyl)sulfonylamino)phenyl)ethyl) 2-(5-chloro-2-[18F]fluorethoxy)phenyl) formamide (2-[18F]fluoroethyl-glibenclamide) was labeled with [18F]fluoride in high yields. Its ability to induce insuline secretion from rat beta-cells in relation to the original glibenclamide was determined.
An improved Flyback converter
2009
This paper presents a modified Flyback converter able to operate with higher efficiency and smaller size, overcoming most of the conventional flyback converter drawbacks, and also keeping its low cost and simplicity. In particular, the proposed converter allows the mosfet off voltage to be reduced and clamped to the input, thus recovering the transformer leakage energy. As a consequence, the duty cycle can be extended to unity, thus reducing the voltage stress across the output rectifier, and lowering both the magnetizing inductance and the transformer bias current values. In addition, due to the auxiliary mosfet, the magnetizing current can become negative, eliminating the discontinuous co…
A demagnetization circuit for forward converters
2009
This paper presents a demagnetization circuit able to operate the forward converter with an higher efficiency and with a wider input range. In particular, by the means of few added components, the magnetizing energy and the leakage one are continuously recovered, and the transformer reset and the primary mosfet OFF voltage clamp to the input, both under steady state and transient operations, are provided. The reduced voltage stress allows the converter to operate with a duty extended to unity over the typical 70% limit of the Active Clamp topology, with smaller output inductance, better converter dynamics and wider input range. Furthermore, thanks to this technique, by employing a duty appr…
Characterization of clamp-on current transformers under nonsinusoidal conditions
2009
This paper reports the performance of clamp-on current transformers under nonsinusoidal conditions. A set of experimental measurements helped to determine the ratio and the phase errors under two conditions: 1) sinusoidal excitation with frequencies from 45 to 1000 Hz and 2) nonsinusoidal excitation using the fundamental frequency and one harmonic, with adjusted phase shift. It was found that ratio and phase errors are affected by the phase angle between the harmonic and the fundamental and the harmonic amplitude. The effects of conductor location in the current transformer's window and of the air-gap width were also investigated. It was concluded that harmonic phase and ratio errors measur…
Enhanced tonic GABAA inhibition in typical absence epilepsy
2009
The cellular mechanisms underlying typical absence seizures, which characterize various idiopathic generalized epilepsies, are not fully understood, but impaired γ-aminobutyric acid (GABA)-ergic inhibition remains an attractive hypothesis. In contrast, we show here that extrasynaptic GABAA receptor–dependent 'tonic' inhibition is increased in thalamocortical neurons from diverse genetic and pharmacological models of absence seizures. Increased tonic inhibition is due to compromised GABA uptake by the GABA transporter GAT-1 in the genetic models tested, and GAT-1 is crucial in governing seizure genesis. Extrasynaptic GABAA receptors are a requirement for seizures in two of the best character…
GABA transporters control GABAergic neurotransmission in the mouse subplate.
2015
The subplate is a transient layer between the cortical plate and intermediate zone in the developing cortex. Thalamo-cortical axons form temporary synapses on subplate neurons (SPns) before invading the cortical plate. Neuronal activity within the subplate is of critical importance for the development of neocortical circuits and architecture. Although both glutamatergic and GABAergic inputs on SPns were reported, short-term plasticity of GABAergic transmission has not been investigated yet. GABAergic postsynaptic currents (GPSCs) were recorded from SPns in coronal neocortical slices prepared from postnatal day 3-4 mice using whole-cell patch-clamp technique. Evoked GPSCs (eGPSCs) elicited b…
Assembly of functional α6β3γ2δ GABAA receptors in vitro
2000
Transgenic mice deficient in the alpha6 subunit of the GABA(A) receptor show reduced levels of the delta subunit protein and an altered GABA(A) receptor pharmacology, suggesting selective assembly mechanisms. Delta reduced the binding of [3H]Ro15-4513 or t-butylbicyclophosphoro[35S]thionate and, to a lesser extent, [3H]muscimol to recombinant alpha1beta1gamma2(delta), alpha4beta1gamma2(delta) and alpha6beta1gamma2(delta) receptors, paralleled by diminished GABA-evoked maximal currents in electrophysiological recordings for the latter one. The delta subunit gave rise to a lower EC50 for GABA and a slowed desensitization indicating its assembly in alpha6beta2delta, alpha6beta1gamma2delta and …
Valutazione dell’insulino-sensibilità tramite clamp euglicemico iperinsulinemico in bambini in terapia sostitutiva con GH.
2018
Background I dati sugli effetti della terapia sostitutiva con ormone somatotropo (GH) sull’insulino-sensibilità sono variabili e talora discordanti tra loro e per gran parte ricavati dall’utilizzo di indici surrogati basali, come Homa-IR, o derivati dall’OGTT, come ISI Matsuda. Scopo Valutare la variazione dell’insulino-sensibilità in un gruppo di pazienti affetti da deficit di GH (GHD) pediatrico confrontando i suddetti indici con il clamp euglicemico iperinsuliemico. Materiali e Metodi In 20 bambini affetti da GHD idiopatico isolato alla diagnosi e dopo 12 mesi di terapia con GH e in 10 controlli con bassa statura costituzionale, oltre ai classici parametri clinico-auxologici (statura, BM…