1,186 research outputs found
A method for the assessment and compensation of positioning errors in industrial robots
Industrial Robots (IR) are currently employed in several production areas as they enable flexible automation and high productivity on a wide range of operations. The IR low positioning performance, however, has limited their use in high precision applications, namely where positioning errors assume importance for the process and directly affect the quality of the final products. Common approaches to increase the IR accuracy rely on empirical relations which are valid for a single IR model. Also, existing works show no uniformity regarding the experimental procedures followed during the IR performance assessment and identification phases. With the aim to overcome these restrictions and further extend the IR usability, this paper presents a general method for the evaluation of IR pose and path accuracy, primarily focusing on instrumentation and testing procedures. After a detailed description of the experimental campaign carried out on a KUKA KR210 R2700 Prime robot under different operating conditions (speed, payload and temperature state), a novel online compensation approach is presented and validated. The position corrections are processed with an industrial PC by means of a purposely developed application which receives as input the position feedback from a laser tracker. Experiments conducted on straight paths confirmed the validity of the proposed approach, which allows remarkable reductions (in the order of 90%) of the orthogonal deviations and in-line errors during the robot movements
High prevalence of patent foramen ovale in migraine with aura
In this study we evaluated the presence of patent foramen ovale (PFO) in a cohort of 25 consecutive patients suffering from migraine with aura (MA) during an attack presenting to the emergency ward of an Italian hospital. Patients underwent brain magnetic resonance imaging (MRI) with contrast medium, routine coagulation tests, contrast transcranial echocolourâcoded sonography (câTCCS) and transoesophageal echocardiography (TEE). Of the enrolled patients, 88.7% showed a PFO according to the câTCCS test, whereas only in 72% TEE confirmed the presence of PFO. This discordance could be due to the fact that câTCCS is more sensitive even with shunts with minimal capacity also located in the pulmonary vasculature. After surgical treatment of the PFO, MA disappeared within two months. Also, the treatment with warfarin as well as with acetylsalicylic acid and flunarizine was able to dramatically reduce the frequency of migraine attacks. These data indicate a higher prevalence of PFO in MA vs. normal population (OR=2.92) and could suggest that the presence of arteriovenous (AV) shunts could represent a trigger for MA attacks as well as for stroke, but more studies are needed to confirm this preliminary hypothesis
On the Microscopic Origin of Cholesteric Pitch
We present a microscopic analysis of the instability of the nematic phase to
chirality when molecular chirality is introduced perturbatively. We show that
previously neglected short-range biaxial correlations play a crucial role in
determining the cholesteric pitch. We propose an order parameter which
quantifies the chirality of a molecule.Comment: RevTeX 3.0, 4 pages, one included eps figure. Published versio
Inter-Strain Epigenomic Profiling Reveals a Candidate IAP Master Copy in C3H Mice.
Insertions of endogenous retroviruses cause a significant fraction of mutations in inbred mice but not all strains are equally susceptible. Notably, most new Intracisternal A particle (IAP) ERV mutagenic insertions have occurred in C3H mice. We show here that strain-specific insertional polymorphic IAPs accumulate faster in C3H/HeJ mice, relative to other sequenced strains, and that IAP transcript levels are higher in C3H/HeJ embryonic stem (ES) cells compared to other ES cells. To investigate the mechanism for high IAP activity in C3H mice, we identified 61 IAP copies in C3H/HeJ ES cells enriched with H3K4me3 (a mark of active promoters) and, among those tested, all are unmethylated in C3H/HeJ ES cells. Notably, 13 of the 61 are specific to C3H/HeJ and are members of the non-autonomous 1Î1 IAP subfamily that is responsible for nearly all new insertions in C3H. One copy is full length with intact open reading frames and hence potentially capable of providing proteins i
Stratigrafia ed assetto geometrico dellâUnitĂ del Sannio nel settore settentrionale dei monti del Matese
New stratigraphic and biostratigraphic data arising from the
realization of the Sheet No. 405 "Campobasso" of the new Geological
map of Italy (1:50.000 scale - CARG Project) allowed, for the first time
in this area, to stratigraphically and cartographically define all the ranges
composing the basinal Sannio Unit Auct.. Structural analysis and the
chronostratigraphic redefinition of siliciclastic deposits covering the
Sannio Unit and the carbonate platform successions of the Matese-
Frosolone Units, indicate two main evolutionary stages in the Miocene-
Pliocene structuring of this portion of the Southern Apennines. In the
first stage, starting before Serravallian times, E-verging contraction
affected exclusively the basinal units together with their siliciclastic
cover. During the second stage, beginning after early Messinian times,
NE-verging compression involved both the basinal Sannio Unit and the
Matese-Frosolone Units.UnpublishedISPRA - Roma, Italy2.2. Laboratorio di paleomagnetismorestricte
Effects of miRNA-15 and miRNA-16 expression replacement in chronic lymphocytic leukemia : implication for therapy
This work was supported by: Associazione Italiana Ricerca sul Cancro (AIRC) Grant 5 x mille n.9980, (to M.F., F.M. A. N., P.T. and M.N.) ; AIRC I.G. n. 14326 (to M.F.), n.10136 and 16722 (A.N.), n.15426 (to F.F.). AIRC and Fondazione CaRiCal co-financed Multi Unit Regional Grant 2014 n.16695 (to F.M.). Italian Ministry of Health 5x1000 funds (to S.Z. and F.F). A.G R. was supported by Associazione Italiana contro le Leucemie-Linfomi-Mielomi (AIL) Cosenza - Fondazione Amelia Scorza (FAS). S.M. C.M., M.C., L.E., S.B. were supported by AIRC.Peer reviewedPostprin
Clinical and pathology characterization of small nerve fiber neuro(no)pathy in cerebellar ataxia with neuropathy and vestibular areflexia syndrome
Background and purpose: Biallelic mutation/expansion of the gene RFC1 has been described in association with a spectrum of manifestations ranging from isolated sensory neuro(no)pathy to a complex presentation as cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS). Our aim was to define the frequency and characteristics of small fiber neuropathy (SFN) in RFC1 disease at different stages. Methods: RFC1 cases were screened for SFN using the Neuropathic Pain Symptom Inventory and Composite Autonomic Symptom Score 31 questionnaires. Clinical data were retrospectively collected. If available, lower limb skin biopsy samples were evaluated for somatic epidermal and autonomic subepidermal structure innervation and compared to healthy controls (HCs). Results: Forty patients, median age at onset 54 years (interquartile range [IQR] 49â61) and disease duration 10 years (IQR 6â16), were enrolled. Mild-to-moderate positive symptoms (median Neuropathic Pain Symptom Inventory score 12.1/50, IQR 5.5â22.3) and relevant autonomic disturbances (median Composite Autonomic Symptom Score 31 37.0/100, IQR 17.7â44.3) were frequently reported and showed scarce correlation with disease duration. A non-length-dependent impairment in nociception was evident in both clinical and paraclinical investigations. An extreme somatic denervation was observed in all patients at both proximal (fibers/mm, RFC1 cases 0.0 vs. HCs 20.5, p < 0.0001) and distal sites (fibers/mm, RFC1 cases 0.0 vs. HCs 13.1, p < 0.0001); instead only a slight decrease was observed in cholinergic and adrenergic innervation of autonomic structures. Conclusions: RFC1 disease is characterized by a severe and widespread somatic SFN. Skin denervation may potentially represent the earliest feature and drive towards the suspicion of this disorder
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