804 research outputs found
Active primate simulator Final report
Systems engineering data and design specifications for Biosatellite active primate simulato
Seed morphology and seed coat structure in Mediterranean plants: implication for evolution, taxonomy and germinative performance
A better understanding of morphological, ultra-structural and anatomical seed coat characteristics can contribute to explain and predict seed performance under certain environmental conditions and select the most suitable treatments promoting seed germination. The Seed Banks at the Botanic Gardens of Catania and Palermo (Sicily) are particularly involved in research studies aimed to detect and describe macro- and micro-morphological features of seeds from different plant families and genera, using both light and scanning electron microscopy. These studies mainly aim to 1) recognize and compare inter- and intra-specific variation of seed coat traits, with particular attention on rare and threatened species; 2) evaluate the usefulness of these traits in taxonomic and phylogenetic studies; 3) establish correlations between seed coat structures and seed germination; 4) understand the seed coat adaptive potential and sensitivity to particular ecological conditions and changing environments
Penning collisions of laser-cooled metastable helium atoms
We present experimental results on the two-body loss rates in a
magneto-optical trap of metastable helium atoms. Absolute rates are measured in
a systematic way for several laser detunings ranging from -5 to -30 MHz and at
different intensities, by monitoring the decay of the trap fluorescence. The
dependence of the two-body loss rate coefficient on the excited state
() and metastable state () populations is also investigated.
From these results we infer a rather uniform rate constant
cm/s.Comment: 8 pages, 9 figures, Revte
The phonon dispersion of graphite by inelastic x-ray scattering
We present the full in-plane phonon dispersion of graphite obtained from
inelastic x-ray scattering, including the optical and acoustic branches, as
well as the mid-frequency range between the and points in the Brillouin
zone, where experimental data have been unavailable so far. The existence of a
Kohn anomaly at the point is further supported. We fit a fifth-nearest
neighbour force-constants model to the experimental data, making improved
force-constants calculations of the phonon dispersion in both graphite and
carbon nanotubes available.Comment: 7 pages; submitted to Phys. Rev.
Real-time optical manipulation of cardiac conduction in intact hearts
Optogenetics has provided new insights in cardiovascular research, leading to new methods for cardiac pacing, resynchronization therapy and cardioversion. Although these interventions have clearly demonstrated the feasibility of cardiac manipulation, current optical stimulation strategies do not take into account cardiac wave dynamics in real time. Here, we developed an allâoptical platform complemented by integrated, newly developed software to monitor and control electrical activity in intact mouse hearts. The system combined a wideâfield mesoscope with a digital projector for optogenetic activation. Cardiac functionality could be manipulated either in freeârun mode with submillisecond temporal resolution or in a closedâloop fashion: a tailored hardware and software platform allowed realâtime intervention capable of reacting within 2 ms. The methodology was applied to restore normal electrical activity after atrioventricular block, by triggering the ventricle in response to optically mapped atrial activity with appropriate timing. Realâtime intraventricular manipulation of the propagating electrical wavefront was also demonstrated, opening the prospect for realâtime resynchronization therapy and cardiac defibrillation. Furthermore, the closedâloop approach was applied to simulate a reâentrant circuit across the ventricle demonstrating the capability of our system to manipulate heart conduction with high versatility even in arrhythmogenic conditions. The development of this innovative optical methodology provides the first proofâofâconcept that a realâtime optically based stimulation can control cardiac rhythm in normal and abnormal conditions, promising a new approach for the investigation of the (patho)physiology of the heart
Celiac disease and headache in children: A narrative state of the art
Celiac disease (CD) is one of the most important entity of the wide spectrum of gluten-related disorders (GRDs). It is well known that neurological manifestation can be present either at the onset of CD, or appear during the development of the pathology, and different can be the neurologic findings. Clinical features are very variable, ranging from typical manifestations of gastrointestinal involvement to neurologic symptom. The most frequent neurologic signs reported were headache, epileptic seizure, migraine, mental retardation, ataxia and attention deficit and hyperactive disorder. Headache either in form of migraine, or in non-specific form represents one of the main clinical presentation in CD. The aim of this work is to provide a narrative review of the pediatric literature focused on the cephalalgic features of children with CD evaluating the potential benefits of a gluten free diet (GFD). Papers were identified by searching for related literature in Medline (PubMed) and Embase using the words âCeliac Diseaseâ and âHeadacheâ or âMigraineâ by specifying âchildrenâ/âpaediatric ageâ for reports published since 1972 till 31th October 2018. According to our inclusion criteria, a total of 25 papers has been evaluated. Although it is still controversial if headache is prevalent in CD children a correct compliance to a GFD seems to improve the neurological symptoms even if the underlying pathogenic relationship between CD and neurologic system involvement is still not fully understood. (www.actabiomedica.it)
Efficient magneto-optical trapping of a metastable helium gas
This article presents a new experiment aiming at BEC of metastable helium
atoms. It describes the design of a high flux discharge source of atoms and a
robust laser system using a DBR diode coupled with a high power Yb doped fiber
amplifier for manipulating the beam of metastable atoms. The atoms are trapped
in a small quartz cell in an extreme high vacuum. The trapping design uses an
additional laser (repumper) and allows the capture of a large number of
metastable helium atoms (approximately ) in a geometry favorable for
loading a tight magnetostatic trap.Comment: 12 pages, 7 figures, Late
Probing mechanotransduction in living cells by optical tweezers and FRET-based molecular force microscopy
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