Deformation Control in Rest-to-Rest Motion of Mechanisms with Flexible Links

This paper develops and validates experimentally a feedback strategy for the reduction of the link deformations in rest-to-rest motion of mechanisms with flexible links, named Delayed Reference Control (DRC). The technique takes advantage of the inertial coupling between rigid-bodymotion and elasticmotion to control the undesired link deformations by shifting in time the position reference through an action reference parameter. The action reference parameter is computed on the fly based on the sensed strains by solving analytically an optimization problem. An outer control loop is closed to compute the references for the position controllers of each actuator, which can be thought of as the inner control loop. The resulting multiloop architecture of the DRC is a relevant advantage over several traditional feedback controllers: DRC can be implemented by just adding an outer control loop to standard position controllers. A validation of the proposed control strategy is provided by applying the DRC to the real-time control of a four-bar linkage

Evidences of spin-temperature in Dynamic Nuclear Polarization: an exact computation of the EPR spectrum

In dynamic nuclear polarization (DNP) experiments, the compound is driven out-of-equilibrium by microwave (MW) irradiation of the radical electron spins. Their stationary state has been recently probed via electron double resonance (ELDOR) techniques showing, at low temperature, a broad depolarization of the electron paramagnetic resonance (EPR) spectrum under microwave irradiation. In this theoretical manuscript, we develop a numerical method to compute exactly the EPR spectrum in presence of dipolar interactions. Our results reproduce the observed broad depolarisation and provide a microscopic justification for spectral diffusion mechanism. We show the validity of the spin-temperature approach for typical radical concentration used in dissolution DNP protocols. In particular once the interactions are properly taken into account, the spin-temperature is consistent with the non-monotonic behavior of the EPR spectrum with a wide minimum around the irradiated frequency.Comment: 8 pages, 7 figures. Title and abstract change

Measuring the degree of “nanotilization” of volcanic glasses:Understanding syn-eruptive processes recorded in melt inclusions

Publisher's version (útgefin grein)Iron and water content substantially affect the physical properties of natural silicate melts and may, therefore, influence magmatic and volcanic processes such as crystallization, degassing, flow behaviour and eruptive style. Here we present Raman spectroscopic data for a set of synthetic and natural multicomponent glasses with varying iron oxidation state and water content. We systematically study the effect of different Raman excitation sources on the spectral response of both crystal free and magnetite nanolite bearing glasses spanning basaltic to calc- and per-alkaline rhyolitic compositions. Based on these data we document changes in Raman spectra resulting from the formation of nano-scale crystals. We show that the peak located at ~970 cm−1 is directly related to the presence of Fe2O3 dissolved in the quenched melt structure and that this feature is present regardless of the chemical composition of the sample and the Raman excitation source. We further show that a peak between 670 and 690 cm−1, which is not related to any other spectral feature of the glass structure, reveals the presence of nanolites. Based on systematic spectral investigations of this feature, we present a new index that allows to identify if iron is present in the nanocrystalline state and/or bound in the glass structure. Since the melt structural and physical effects of the formation of nanolites can heavily affect the flow behaviour of melts and the eruptive style of volcanoes, the results presented in this study significantly broaden the application of Raman spectroscopy for investigations of nano-heterogeneity in synthetic and natural glasses. We apply this method to study both the degree of nanolitization as well as the H2O content and iron oxidation state of groundmass glasses as well as melt inclusions and glass embayments in explosive products from Pantelleria island (Italy). We observe that the process of nanotilization is not purely restricted to magnetite nanolites but that Raman spectroscopy may also identify the incipient crystalization of pyroxene and feldspar at sub-micron scale. The data document that nanolite formation correlates well with the observed intensity of the respective eruptions suggesting that structural changes in the melt, caused by incipient crystallization play an important role in defining the eruptive style of relatively low viscosity magmas.D. Di Genova was supported by the NSFGEO-NERC “Quantifying disequilibrium processes in basaltic volcanism” (reference: NE/N018567/1). A. Caracciolo was supported by the Erasmus+ traineeship program from Pisa University (Italy). S. Kolzenburg acknowledges funding from H2020 MSCA grant “DYNAVOLC” (#795044).Peer Reviewe

Antimicrobial resistance among Escherichia coli that cause childhood community-acquired urinary tract infections in Northern Italy

<p>Abstracts</p> <p>Background</p> <p>Resistance rate of <it>Escherichia coli </it>against antimicrobials that are commonly prescribed in pediatric urinary tract infections is currently a matter of concern.</p> <p>Methods</p> <p>The antimicrobial susceptibility patterns of uropathogenic <it>Escherichia coli </it>strains to the common antibimcrobials ampicillin, cotrimoxazole, coamoxyclav, ceftazidime, ceftriaxone, nitrofurantoin, and gentamycin were determined in 177 children aged from 2 to 36 months. They presented with their first symptomatic community acquired urinary tract infection at the Department of Pediatrics, San Leopoldo Mandic Hospital, Merate-Lecco.</p> <p>Results</p> <p>High rates of ampicillin (inpatients: 50%; outpatients: 52%) resistance were identified. The resistance for cotrimoxazole (inpatients: 22%; outpatients: 15%) and especially coamoxyclav (inpatients: 6%; outpatients: 10%) was less pronounced than that to ampicillin. No resistance or less than 1% of resistance was identified for ceftazidime, ceftriaxone, nitrofurantoin, and gentamycin both in inpatients and in outpatients.</p> <p>Conclusions</p> <p>Italian children affected with a community acquired urinary tract infection are initially managed orally with coamoxyclav or parenterally with ceftriaxone. The results of the present retrospective analysis support this attitude. Parenteral ceftriaxone or an aminoglycoside should be considered for patients on antimicrobial prophylaxis or recently prescribed antimicrobials.</p

Inhibiting the growth of 3D brain cancer models with bio-coronated liposomal temozolomide

Nanoparticles (NPs) have emerged as an effective means to deliver anticancer drugs into the brain. Among various forms of NPs, liposomal temozolomide (TMZ) is the drug-of-choice for the treatment and management of brain tumours, but its therapeutic benefit is suboptimal. Although many possible reasons may account for the compromised therapeutic efficacy, the inefficient tumour penetration of liposomal TMZ can be a vital obstacle. Recently, the protein corona, i.e., the layer of plasma proteins that surround NPs after exposure to human plasma, has emerged as an endogenous trigger that mostly controls their anticancer efficacy. Exposition of particular biomolecules from the corona referred to as protein corona fingerprints (PCFs) may facilitate interactions with specific receptors of target cells, thus, promoting efficient internalization. In this work, we have synthesized a set of four TMZ-encapsulating nanomedicines made of four cationic liposome (CL) formulations with systematic changes in lipid composition and physical−chemical properties. We have demonstrated that precoating liposomal TMZ with a protein corona made of human plasma proteins can increase drug penetration in a 3D brain cancer model derived from U87 human glioblastoma multiforme cell line leading to marked inhibition of tumour growth. On the other side, by fine-tuning corona composition we have also provided experimental evidence of a non-unique effect of the corona on the tumour growth for all the complexes investigated, thus, clarifying that certain PCFs (i.e., APO-B and APO-E) enable favoured interactions with specific receptors of brain cancer cells. Reported results open new perspectives into the development of corona-coated liposomal drugs with enhanced tumour penetration and antitumour efficacy

Additive beneficial effects of beta blockers in the prevention of symptomatic heart failure

The prevention of symptomatic heart failure represents the treatment of patients in the A and B stages of AHA/ACC heart failure classification. Stage A refers to patients without structural heart disease but at risk to develop chronic heart failure. The major risk factors in stage A are hypertension, diabetes, atherosclerosis, family history of coronary artery disease and history of cardiotoxic drug use. In this stage, blockers hypertension is the primary area in which beta blockers may be useful. Beta blockers seem not to be superior to other medication in reducing the development of heart failure due to hypertension. Stage B heart failure refers to structural heart disease but without symptoms of heart failure. This includes patients with asymptomatic valvular disease, asymptomatic left ventricular (LV) dysfunction, previous myocardial infarction with or without LV dysfunction. In asymptomatic valvular disease no data are available on the efficacy of beta blockers to prevent heart failure. In asymptomatic LV dysfunction only few asymptomatic patients have been enrolled in the trials which tested beta blockers. NYHA I patients were barely 228 in the MDC, MERIT and ANZ trials altogether. The REVERT trial was the only trial focusing on NYHA I patients with LV ejection fraction less than 40%. Metoprolol extended release on top of ACE inhibitors ameliorated LV systolic volume and ejection fraction. A post hoc analysis of the SOLVD Prevention trial demonstrated that beta blockers reduced death and development of heart failure. Similar results were reported in post MI patients in a post hoc analysis of the SAVE trial (Asymptomatic LV failure post myocardial infarction). In the CAPRICORN trial about 65% of the patients were not taking diuretics and then could be considered asymptomatic. The study revealed a reduction in mortality and a non-significant trend toward reduction of death and hospital admission for heart failure. Conclusions: beta blockers are not specifically indicated in stage A heart failure. On the contrary, in most of the stage B patients, and particularly after MI, beta blockers are indicated to reduce mortality and, probably, also the progression toward symptomatic heart failure

Misinterpretation of an inflammatory FDG uptake in a patient treated for Hodgkin lymphoma: a case report

Hodgkin Lymphoma (HL) is a malignancy involving lymph nodes and lymphatic system. [18F]F-FDG PET/CT (FDG-PET) imaging is routinely used for staging, to assess early chemotherapy response (interim FDG-PET), at the end of treatment (EoT FDG-PET) and for the identification of disease recurrence.We present a case of a 39-year-old man treated for HL. FDG-PET scans performed after first line therapy (both Interim PET and at the end of therapy) demonstrated a persistent and significant mediastinal FDG uptake. The patient was treated with a second line therapy but the FDG-PET uptake did not change. After board discussion a new surgical, thoracoscopy-guided biopsy was performed. Histopathology demonstrated a dense fibrous tissue with occasional chronic inflammatory infiltrates.Persistent FDG-PET positivity may suggest refractory or relapsed disease. However, occasionally, non-malignant conditions are responsible for a persistent FDG uptake, not related to primary disease. An accurate evaluation of clinical history and previous imaging exams is mandatory for clinicians and others experts to avoid misinterpretations of FDG-PET results. Nevertheless, in some cases, only a more invasive procedure, such as a biopsy, may finally lead to a definitive diagnosis

Anyons and Quantum Groups

Anyonic oscillators with fractional statistics are built on a two-dimensional square lattice by means of a generalized Jordan-Wigner construction, and their deformed commutation relations are thoroughly discussed. Such anyonic oscillators, which are non-local objects that must not be confused with $q$-oscillators, are then combined \`a la Schwinger to construct the generators of the quantum group $SU(2)_q$ with $q=\exp({\rm i}\pi\nu)$, where $\nu$ is the anyonic statistical parameter.Comment: 26 pp., TeX file (figures on request), DFTT 73/92 and ITP-SB-92-7

Slave Anyons in the tt-JJ Model at the Supersymmetric Point

We discuss the properties of the supersymmetric $t$-$J$ model in the formalism of the slave operators. In particular we introduce a generalized abelian bosonization for the model in two dimensions, and show that holons and spinons can be anyons of arbitrary complementary statistics (slave anyon representation). The braiding properties of these anyonic operators are thoroughly analyzed, and are used to provide an explicit linear realization of the superalgebra $SU(1|2)$. Finally, we prove that the Hamiltonian of the $t$-$J$ model in the slave anyon representation is invariant under $SU(1|2)$ for $J=2\,t$.Comment: 37 pp., TeX file (3 figures on request), DFTT 30/93 and ITP-SB-93-3