Experimental Validation of Contact Dynamics for In-Hand Manipulation

This paper evaluates state-of-the-art contact models at predicting the motions and forces involved in simple in-hand robotic manipulations. In particular it focuses on three primitive actions --linear sliding, pivoting, and rolling-- that involve contacts between a gripper, a rigid object, and their environment. The evaluation is done through thousands of controlled experiments designed to capture the motion of object and gripper, and all contact forces and torques at 250Hz. We demonstrate that a contact modeling approach based on Coulomb's friction law and maximum energy principle is effective at reasoning about interaction to first order, but limited for making accurate predictions. We attribute the major limitations to 1) the non-uniqueness of force resolution inherent to grasps with multiple hard contacts of complex geometries, 2) unmodeled dynamics due to contact compliance, and 3) unmodeled geometries dueto manufacturing defects.Comment: International Symposium on Experimental Robotics, ISER 2016, Tokyo, Japa

How to combine CTA, 99mTc-WBC SPECT/CT, and [18F]FDG PET/CT in patients with suspected abdominal vascular endograft infections?

Purpose - We aimed at comparing Tc-99m-HMPAO white blood cells (Tc-99m-WBC) scintigraphy, 18fluorine-fluorodeoxyglucose ([F-18]FDG) positron emission tomography/computed tomography (PET/CT) and CT angiography (CTA) in patients with suspected abdominal vascular graft or endograft infection (VGEI). Moreover, we attempted to define a new visual score for interpreting [F-18]FDG PET/CT scans aiming at increasing its specificity. Methods - We prospectively compared Tc-99m-WBC SPECT/CT, [F-18]FDG PET/CT, and CTA in 26 patients with suspected abdominal VGEI. WBC scans were performed and interpreted according to EANM recommendations. [F-18]FDG PET/CT studies were assessed with both qualitative (Sah's scale and new visual score) and semi-quantitative analyses. CTA images were interpreted according to MAGIC criteria. Microbiology, histopathology or a clinical follow-up of at least 24 months were used to achieve final diagnosis. Results - Eleven out of 26 patients were infected. [F-18]FDG PET/CT showed 100% sensitivity and NPV, with both scoring systems, thus representing an efficient tool to rule out the infection. The use of a more detailed scoring system provided statistically higher specificity compared to the previous Sah's scale (p = 0.049). Tc-99m-WBC SPECT/CT provided statistically higher specificity and PPV than [F-18]FDG PET/CT, regardless the interpretation criteria used and it can be, therefore, used in early post-surgical phases or to confirm or rule out a PET/CT finding. Conclusions - After CTA, patients with suspected late VGEI should perform a [F-18]FDG PET/CT given its high sensitivity and NPV. However, given its lower specificity, positive results should be confirmed with Tc-99m-WBC scintigraphy. The use of a more detailed scoring system reduces the number of Tc-99m-WBC scans needed after [F-18]FDG PET/CT. Nevertheless, in suspected infections within 4 months from surgery, Tc-99m-WBC SPECT/CT should be performed as second exam, due to its high accuracy in differentiating sterile inflammation from infection

The impact of COVID-19 on radiological findings in patients accessing the emergency department: a multicentric study

The aim of this multicentric study is to illustrate how the COVID-19 pandemic lockdown affected the workload and outcomes of radiological examinations in emergency radiology

Vegetarian and vegan weaning of the infant: How common and how evidence-based? a population-based survey and narrative review

Background: Vegetarian and vegan weaning have increasing popularity among parents and families. However, if not correctly managed, they may lead to wrong feeding regimens, causing severe nutritional deficiencies requiring specific nutritional support or even the need for hospitalization. Aim: To assess the prevalence of vegetarian and vegan weaning among Italian families and to provide an up-to-date narrative review of supporting evidence. Materials and methods: We investigated 360 Italian families using a 40-item questionnaire. The narrative review was conducted searching scientific databases for articles reporting on vegetarian and vegan weaning. Results: 8.6% of mothers follow an alternative feeding regimen and 9.2% of infants were weaned according to a vegetarian or vegan diet. The breastfeeding duration was longer in vegetarian/vegan infants (15.8 vs. 9.7 months; p < 0.0001). Almost half of parents (45.2%) claim that their pediatrician was unable to provide sufficient information and adequate indications regarding unconventional weaning and 77.4% of parents reported the pediatrician’s resistance towards alternative weaning methods. Nine studies were suitable for the review process. The vast majority of authors agree on the fact that vegetarian and vegan weaning may cause severe nutritional deficiencies, whose detrimental effects are particularly significant in the early stages of life. Discussion and conclusion: Our results show that alternative weaning methods are followed by a significant number of families; in half of the cases, the family pediatrician was not perceived as an appropriate guide in this delicate process. To date, consistent findings to support both the safety and feasibility of alternative weaning methods are still lacking. Since the risk of nutritional deficiencies in the early stages of life is high, pediatricians have a pivotal role in guiding parents and advising them on the most appropriate and complete diet regimen during childhood. Efforts should be made to enhance nutritional understanding among pediatricians as an unsupervised vegetarian or vegan diet can cause severe nutritional deficiencies with possible detrimental long-term effects

SIR-C/X-SAR data calibration and ground truth campaign over the NASA-CB1 test-site

During the Space Shuttle Endeavour mission in October 1994, a remote-sensing campaign was carried out with the objectives of both radiometric and polarimetric calibration and ground truth data acquisition of bare soils. This paper presents the results obtained in the experiment. Polarimetric cross-talk and channel imbalance values, as well as radiometric calibration parameters, have been found to be within the science requirements for SAR images. Regarding ground truth measurements, a wide spread in the height rms values and correlation lengths has been observed, which has motivated a critical revisiting of surface parameters descriptors

Osteogenic differentiation of mesenchymal stem cells from dental bud: Role of integrins and cadherins

Several studies have reported the beneficial effects of mesenchymal stem cells (MSCs) in tissue repair and regeneration. New sources of stem cells in adult organisms are continuously emerging; dental tissues have been identified as a source of postnatal MSCs. Dental bud is the immature precursor of the tooth, is easy to access and we show in this study that it can yield a high number of cells with ≥ 95% expression of mesenchymal stemness makers and osteogenic capacity. Thus, these cells can be defined as Dental Bud Stem Cells (DBSCs) representing a promising source for bone regeneration of stomatognathic as well as other systems. Cell interactions with the extracellular matrix (ECM) and neighboring cells are critical for tissue morphogenesis and architecture; such interactions are mediated by integrins and cadherins respectively. We characterized DBSCs for the expression of these adhesion receptors and examined their pattern during osteogenic differentiation. Our data indicate that N-cadherin and cadherin-11 were expressed in undifferentiated DBSCs and their expression underwent changes during the osteogenic process (decreasing and increasing respectively), while expression of E-cadherin and P-cadherin was very low in DBSCs and did not change during the differentiation steps. Such expression pattern reflected the mesenchymal origin of DBSCs and confirmed their osteoblast-like features. On the other hand, osteogenic stimulation induced the upregulation of single subunits, αV, β3, α5, and the formation of integrin receptors α5β1 and αVβ3. DBSCs differentiation toward osteoblastic lineage was enhanced when cells were grown on fibronectin (FN), vitronectin (VTN), and osteopontin (OPN), ECM glycoproteins which contain an integrin-binding sequence, the RGD motif. In addition we established that integrin αVβ3 plays a crucial role during the commitment of MSCs to osteoblast lineage, whereas integrin α5β1 seems to be dispensable. These data suggest that functionalization of biomaterials with such ECM proteins would improve bone reconstruction therapies starting from dental stem cells

The Present Development of CsI Rich Detectors for the ALICE Experiment at CERN

The ALICE Collaboration plans to implement a 12m^2 array consisting of 7 proximity focussed C6F^14 liquid radiator RICH modules devoted to the particle identification in the momentum range: 1 GeV/c - 3.5 GeV/c for pions and kaons. A large area CSI-RICH prototype has been designed and built with the aim to validate the detector parameter assumptions made to predict the performance of the High Momentum Particle Identification System (HMPID) of the ALICE Experiment. The main elements of the prototype will be described with emphasis on the engineering solutions adopted. First results from the analysis of multitrack events recorded with this prototype exposed to hadron beams at the CERN SPS will be discussedList of FiguresFigure 1 General view of the ALICE lay-outFigure 2 Schematic layout of the fast CsI-RICHFigure 3 Perspective view of the HMPID layout with the seven RICH modules tilted according to their position with respect to the interaction vertex. The frame that supports the detectors is also shownFigure 4 Top view of the photodetector anode plane with the wire support spacer. One CsI board, out of six forming the pad cathode plane, is also shown.Figure 5 Perspective view of the HMPID honeycomb panel with the three radiator vesselsFigure 6 Cut away view of the HMPID CsI-RICH showing separately each detector component. Kapton buses that carry signals from the pads to the readout electronics are also shownFigure 7 a)number of resolved photoelectrons per event, b)reconstructed Cherenkov angle per photonFigure 8 C6F14 transmission plots before and after the molecular sieve purificationFigure 9 Display plot showing an SPS event. Three tracks are reconstructed by using the tracking chamber telescope, the associated rings are shown in the HMPID prototypeThis publication also appears as INT-98-20

Review of the development of cesium iodide photocathodes for application to large RICH detectors

CsI photocathodes were studied in order to evaluate their potential use as large photo converters in RICH detectors for the PID system of ALICE at LHC in heavy-ion collider mode. It has been demonstrated that a quantum efficiency close to the reference value obtained on small samples can be obtained on CsI layers evaporated on large pad electrodes operated in a MWPC at atmospheric pressure. We present a survey of the results obtained in the laboratory on small samples irradiated with UV-monochromatic beams and with large area RICH detectors of proximity-focusing geometry in a 3 GeV/c pion beam

A large area CsI RICH Detector in ALICE at LHC

A 1m2 CsI RICH prototype has been successfully tested in a hadron beam at CERN SPS. The prototype, fully equipped with 15k electronic channels, has been used to identify particles coming from pi-Be interactions. Track reconstruction has been performed by using a telescope consisting of four gas pad chambers. A detailed description of the detector will be presented and results from the test will be discussed.List of figuresFigure 1 Expected proton and antiproton yields including jet quenching mechanism in central Pb-Pb collisions at LHC.Figure 2 Schematic view of the HMPID CsI-RICHFigure 3 Experimental layout used at the SPS/H4 test beamFigure 4 Distributions of the mean number, per ring, of pad hits (Npad), electrons (Ntot) and Cherenkov photoelectrons (Nres) as a function of the single-electron mean pulse heightFigure 5 Mean single-electron pulse height as a function of high voltage measured at the centre of each of the four photocathodesFigure 6 Evaluation of the uniformity of the chamber gain for the photocathode PC32Figure 7 Azimuthal distribution of the photon pad hits in the Cherenkov fiducial zone (HV=2050 V)Figure 8 Photon angle (a) and track Cherenkov angle (b) distributions for beam events at the SPSFigure 9 Track density on the HMPID cathode plane in real 350 GeV/c pi--Be eventsFigure 10 Three dimensional display of an SPS 350 GeV/c pi--Be event. Eleven tracks are reconstructed in the telescope by requiring one hit on each pad chamber to reconstruct a track</UL