The Steiner problem for infinitely many points

Let AA be a given compact subset of the euclidean space. We consider the problem of finding a compact connected set SS of minimal 11-dimensional Hausdorff measure, among all compact connected sets containing AA. We prove that when AA is a finite set any minimizer is a finite tree with straight edges, thus recovery the classical Steiner Problem. Analogously, in the case when AA is countable, we prove that every minimizer is a (possibly) countable union of straight segments

The S0_0(0) structure in highly compressed hydrogen and the orientational transition

A calculation of the rotational S$_0$(0) frequencies in high pressure solid para-hydrogen is performed. Convergence of the perturbative series at high density is demonstrated by the calculation of second and third order terms. The results of the theory are compared with the available experimental data to derive the density behaviour of structural parameters. In particular, a strong increase of the value of the lattice constant ratio $c/a$ and of the internuclear distance is determined. Also a decrease of the anisotropic intermolecular potential is observed which is attributed to charge transfer effects. The structural parameters determined at the phase transition may be used to calculate quantum properties of the rotationally ordered phase.Comment: accepted Europhysics Letter

Cerebral venous thrombosis: a practical guide

All neurologists need to be able to recognise and treat cerebral venous thrombosis (CVT). It is difficult to diagnose, partly due to its relative rarity, its multiple and various clinical manifestations (different from ‘conventional’ stroke, and often mimicking other acute neurological conditions), and because it is often challenging to obtain and interpret optimal and timely brain imaging. Although CVT can result in death or permanent disability, it generally has a favourable prognosis if diagnosed and treated early. Neurologists involved in stroke care therefore also need to be aware of the treatments for CVT (with varying degrees of supporting evidence): the mainstay is prompt anticoagulation but patients who deteriorate despite treatment can be considered for endovascular procedures (endovascular thrombolysis or thrombectomy) or neurosurgery (decompressive craniotomy). This review summarises current knowledge on the risk factors, diagnosis, treatment and prognosis of CVT in adults, and highlights some areas for future research

Pressure-tuning of the electron-phonon coupling: the insulator to metal transition in manganites

A comprehensive understanding of the physical origin of the unique magnetic and transport properties of A_(1-x)A'^xMnO_3 manganites (A = trivalent rare-earth and A' = divalent alkali-earth metal) is still far from being achieved. The complexity of these systems arises from the interplay among several competing interactions of comparable strength. Recently the electron-phonon coupling, triggered by a Jahn-Teller distortion of the MnO_6 octahedra, has been recognised to play an essential role in the insulator to metal transition and in the closely related colossal magneto-resistance. The pressure tuning of the octahedral distortion gives a unique possibility to separate the basic interactions and, at least in principle, to follow the progressive transformation of a manganite from an intermediate towards a weak electron-phonon coupling regime. Using a diamond anvil cell, temperature and pressure-dependent infrared absorption spectra of La_(0.75)Ca_(0.25)MnO_3 have been collected and, from the spectral weight analysis, the pressure dependence of the insulator to metal transition temperature T_IM has been determined for the first time up to 11.2 GPa. The T_IM(P) curve we proposed to model the present data revealed a universality character in accounting for the whole class of intermediate coupling compounds. This property can be exploited to distinguish the intermediate from the weak coupling compounds pointing out the fundamental differences between the two coupling regimes.Comment: 8 pages, 4 figure

New generation anaplastic lymphoma kinase inhibitors

Anaplastic lymphoma kinase (ALK) gene translocations are pro-tumoral driver alterations that encompass 3*7% of non-squamous non-small cell lung cancer (NSCLC) with specific, clinic and histologic features. The therapeutic strategy depends on anti-ALK tyrosine kinase inhibitors (TKIs) of which crizotinib was the first approved for clinical use. Despite its use improved significantly progression-free survival, overall response rate and duration of response of this illness, after a median period of 10.9 months all patients progress due to the development of acquired resistance mutations in the ALK tyrosine kinase domain in approximately one third of patients. Moreover, 60-90% of patients treated with crizotinib has a progression in the central nervous system (CNS) in absence of extracranial worsening of the disease. This is primarily attributed to poor CNS penetration by crizotinib as many pre-clinical and clinical models suggest. For instance, in order to overtake acquired resistance to crizotinib, prolong the control of the disease and manage CNS localizations, several II and III generation TKIs have been developed. Some of them were approved after the failure of crizotinib (ceritinib, alectinib, brigatinib and lorlatinib) and in first line setting (ceritinib, alectinib and brigatinib) while others are still under evaluation for TKI-naive patients such as lorlatinib, ensartinib and entrectinib. In this review we will discuss the most recent results of new TKIs in order to describe a fast growing therapeutic landscape in this setting

Raman-like scattering using high energy neutrons: applications to hydrogen and hydrogen-containing materials

The extensive use of Raman spectroscopy in the investigation of the internal molecular motions has been one the most relevant achievements of the last century. Thanks to this experimental technique, thousands of molecular structures have been determined and refined. Nonetheless, the use of photons, mostly in the visible region, has been soon recognized to represent a limiting factor for optically dense materials. The availability of dense beams of high energy neutrons, together with the construction of dedicated spectroscopic instrumentation, has allowed to get rid of this restriction and to take full advantage of the high neutron penetration power in dense matter. Today, the resolving power of neutron instrumentation is not too much dissimilar from that of the corresponding photon instrumentation and the available energy range extends well beyond the eV limit. Thus, allowing to cover the whole vibrational spectrum available to any molecular system. In this contribution, I will show how a dedicated instrument (TOSCA at ISIS) can be effectively used in neutron spectroscopy applications for the investigation of rotovibrational motions in condensed matter systems. Thus becoming an effective aquivalent of a Raman spectrometer, with the invaluable advantage of the neutron penetration power in dense systems. A further advantage of a dedicated high energy neutron spectrometer is represented by the possibility of exploring the application of the Impulse Approximation limit to the center of mass dynamics of molecular systems. By this technique, taking into account the high incoherent neutron scattering cross section of the proton and the extensive energy range available on TOSCA, a wide research area can be exploited allowing to obtain a direct experimental information on the quantum dynamics of liquid and solid bulk hydrogen. Also, it will be shown how the peculiar characteristics of a dedicated neutron Raman instrument can be exploited in the investigation of the quantum dynamics of molecular hydrogen in the nanoconfined geometry of clathrate hydrates, or in detecting its rotational motion on the surface of a carbon nanotube. Last, but not least, important applications of this spectroscopic tool to the investigation of hydrogen-storage materials, including simple and complex light metal hydrides, will be outlined

Combining preclinical tools and models to unravel tumor complexity: Jump into the next dimension

Tumors are complex and heterogeneous diseases characterized by an intricate milieu and dynamically in connection with surrounding and distant tissues. In the last decades, great efforts have been made to develop novel preclinical models able to recapitulate the original features of tumors. However, the development of an in vitro functional and realistic tumor organ is still utopic and represents one of the major challenges to reproduce the architecture of the tumor ecosystem. A strategy to decrypt the whole picture and predict its behavior could be started from the validation of simplified biomimetic systems and then proceed with their integration. Variables such as the cellular and acellular composition of tumor microenvironment (TME) and its spatio-temporal distribution have to be considered in order to respect the dynamic evolution of the oncologic disease. In this perspective, we aim to explore the currently available strategies to improve and integrate in vitro and in vivo models, such as three-dimensional (3D) cultures, organoids, and zebrafish, in order to better understand the disease biology and improve the therapeutic approaches

Age- and sex-related variations in platelet count in Italy: a proposal of reference ranges based on 40987 subjects' data

BACKGROUND AND OBJECTIVES: Although several studies demonstrated that platelet count is higher in women, decreases with age, and is influenced by genetic background, most clinical laboratories still use the reference interval 150-400×10(9) platelets/L for all subjects. The present study was to identify age- and sex-specific reference intervals for platelet count. METHODS: We analysed electronic records of subjects enrolled in three population-based studies that investigated inhabitants of seven Italian areas including six geographic isolates. After exclusion of patients with malignancies, liver diseases, or inherited thrombocytopenias, which could affect platelet count, reference intervals were estimated from 40,987 subjects with the non parametric method computing the 2.5° and 97.5° percentiles. RESULTS: Platelet count was similar in men and women until the age of 14, but subsequently women had steadily more platelets than men. The number of platelets decreases quickly in childhood, stabilizes in adulthood, and further decreases in oldness. The final result of this phenomenon is that platelet count in old age was reduced by 35% in men and by 25% in women compared with early infancy. Based on these findings, we estimated reference intervals for platelet count ×10(9)/L in children (176-452), adult men (141-362), adult women (156-405), old men (122-350) and, old women (140-379). Moreover, we calculated an extended reference interval that takes into account the differences in platelet count observed in different geographic areas. CONCLUSIONS: The age-, sex-, and origin-related variability of platelet count is very wide, and the patient-adapted reference intervals we propose change the thresholds for diagnosing both thrombocytopenia and thrombocytosis in Italy

micrornas and cdh1 regulation in intestinal type gastric cancer

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