On Differentiating Multiple Types of ULF Magnetospheric Waves in Response to Solar Wind Periodic Density Structures.

Identifying the nature and source of ultra-low frequencies (ULF) waves (f ⪅ 4 mHz) at discrete frequencies in the Earth's magnetosphere is a complex task. The challenge comes from the simultaneous occurrence of externally and internally generated waves, and the ability to robustly identify such perturbations. Using a recently developed robust spectral analysis procedure, we study an interval that exhibited in magnetic field measurements at geosynchronous orbit and in-ground magnetic observatories both internally supported and externally generated ULF waves. The event occurred on 9 November 2002 during the interaction of the magnetosphere with two interplanetary shocks that were followed by a train of 90 min solar wind periodic density structures. Using the Wang-Sheeley-Arge model, we mapped the source of this solar wind stream to an active region and a mid-latitude coronal hole just prior to crossing the Heliospheric current sheet. In both the solar wind density and magnetospheric field fluctuations, we separated broad power increases from enhancements at specific frequencies. For the waves at discrete frequencies, we used the combination of satellite and ground magnetometer observations to identify differences in frequency, polarization, and observed magnetospheric locations. The magnetospheric response was characterized by: (a) forced breathing by periodic solar wind dynamic pressure variations below ≈1 mHz, (b) a combination of directly driven oscillations and wave modes triggered by additional mechanisms (e.g., shock and interplanetary magnetic field discontinuity impact, and substorm activity) between ≈1 and 4 mHz, and (c) largely triggered modes above ≈4 mHz.

The FXR agonist obeticholic acid inhibits the cancerogenic potential of human cholangiocarcinoma.

Cholangiocarcinoma (CCA) is an aggressive cancer with high resistance to chemotherapeutics. CCA is enriched in cancer stem cells, which correlate with aggressiveness and prognosis. FXR, a member of the metabolic nuclear receptor family, is markedly down-regulated in human CCA. Our aim was to evaluate, in primary cultures of human intrahepatic CCA (iCCA), the effects of the FXR agonist obeticholic acid (OCA), a semisynthetic bile acid derivative, on their cancerogenic potential. Primary human iCCA cell cultures were prepared from surgical specimens of mucinous or mixed iCCA subtypes. Increasing concentrations (0-2.5 µM) of OCA were added to culture media and, after 3-10 days, effects on proliferation (MTS assay, cell population doubling time), apoptosis (annexin V-FITC/propidium iodide), cell migration and invasion (wound healing response and Matrigel invasion assay), and cancerogenic potential (spheroid formation, clonogenic assay, colony formation capacity) were evaluated. Results: FXR gene expression was downregulated (RT-qPCR) in iCCA cells vs normal human biliary tree stem cells (p < 0.05) and in mucinous iCCA vs mixed iCCA cells (p < 0.05) but was upregulated by addition of OCA. OCA significantly (p < 0.05) inhibited proliferation of both mucinous and mixed iCCA cells, starting at a concentration as low as 0.05 µM. Also, CDCA (but not UDCA) inhibited cell proliferation, although to a much lower extent than OCA, consistent with its different affinity for FXR. OCA significantly induced apoptosis of both iCCA subtypes and decreased their in vitro cancerogenic potential, as evaluated by impairment of colony and spheroid formation capacity and delayed wound healing and Matrigel invasion. In general, these effects were more evident in mixed than mucinous iCCA cells. When tested together with Gemcitabine and Cisplatin, OCA potentiated the anti-proliferative and pro-apoptotic effects of these chemotherapeutics, but mainly in mixed iCCA cells. OCA abolished the capacity of both mucinous and mixed iCCA cells to form colonies when administered together with Gemcitabine and Cisplatin. In subcutaneous xenografts of mixed iCCA cells, OCA alone or combined with Gemcitabine or Cisplatin markedly reduced the tumor size after 5 weeks of treatment by inducing necrosis of tumor mass and inhibiting cell proliferation. In conclusion, FXR is down-regulated in iCCA cells, and its activation by OCA results in anti-cancerogenic effects against mucinous and mixed iCCA cells, both in vitro and in vivo. The effects of OCA predominated in mixed iCCA cells, consistent with the lower aggressiveness and the higher FXR expression in this CCA subtype. These results, showing the FXR-mediated capacity of OCA to inhibit cholangiocarcinogenesis, represent the basis for testing OCA in clinical trials of CCA patients.

Helios Observations of Quasiperiodic Density Structures in the Slow Solar Wind at 0.3, 0.4, and 0.6 AU.

Following previous investigations of quasiperiodic plasma density structures in the solar wind at 1 AU, we show using the Helios1 and Helios2 data their first identification in situ in the inner heliosphere at 0.3, 0.4, and 0.6 AU. We present five events of quasiperiodic density structures with time scales ranging from a few minutes to a couple of hours in slow solar wind streams. Where possible, we locate the solar source region of these events using photospheric field maps from the Mount Wilson Observatory as input for the Wang-Sheeley-Arge model. The detailed study of the plasma properties of these structures is fundamental to understanding the physical processes occurring at the origin of the release of solar wind plasma. Temperature changes associated with the density structures are consistent with these periodic structures developing in the solar atmosphere as the solar wind is formed. One event contains a flux rope, suggesting that the solar wind was formed as magnetic reconnection opened up a previously closed flux tube at the Sun. This study highlights the types of structures that Parker Solar Probe and the upcoming Solar Orbiter mission will observe, and the types of data analyses these missions will enable. The data from these spacecrafts will provide additional in situ measurements of the solar wind properties in the inner heliosphere allowing, together with the information of the other interplanetary probes, a more comprehensive study of solar wind formation.

Experimental search for the violation of Pauli exclusion principle: VIP-2 Collaboration.

The VIolation of Pauli exclusion principle -2 experiment, or VIP-2 experiment, at the Laboratori Nazionali del Gran Sasso searches for X-rays from copper atomic transitions that are prohibited by the Pauli exclusion principle. Candidate direct violation events come from the transition of a 2p electron to the ground state that is already occupied by two electrons. From the first data taking campaign in 2016 of VIP-2 experiment, we determined a best upper limit of [Formula: see text] for the probability that such a violation exists. Significant improvement in the control of the experimental systematics was also achieved, although not explicitly reflected in the improved upper limit. By introducing a simultaneous spectral fit of the signal and background data in the analysis, we succeeded in taking into account systematic errors that could not be evaluated previously in this type of measurements.

Electron transport in ultra-thin films and ballistic electron emission microscopy.

We have developed a calculation scheme for the elastic electron current in ultra-thin epitaxial heterostructures. Our model uses a Keldysh's non-equilibrium Green's function formalism and a layer-by-layer construction of the epitaxial film. Such an approach is appropriate to describe the current in a ballistic electron emission microscope (BEEM) where the metal base layer is ultra-thin and generalizes a previous one based on a decimation technique appropriated for thick slabs. This formalism allows a full quantum mechanical description of the transmission across the epitaxial heterostructure interface, including multiple scattering via the Dyson equation, which is deemed a crucial ingredient to describe interfaces of ultra-thin layers properly in the future. We introduce a theoretical formulation needed for ultra-thin layers and we compare with results obtained for thick Au(1 1 1) metal layers. An interesting effect takes place for a width of about ten layers: a BEEM current can propagate via the center of the reciprocal space ([Formula: see text]) along the Au(1 1 1) direction. We associate this current to a coherent interference finite-width effect that cannot be found using a decimation technique. Finally, we have tested the validity of the handy semiclassical formalism to describe the BEEM current.

Aesthetic comparison between synthetic glue and subcuticular sutures in thyroid and parathyroid surgery: a single-blinded randomised clinical trial.

The aim of our study was to compare, in terms of aesthetic results, the use of synthetic glue to intradermal absorbable sutures in postthyroidectomy and parathyroidectomy wound closure in a single blinded, randomised, per protocol equivalence study. From September 2008 to May 2010, patients undergoing thyroid or parathyroid surgery (with an external approach) at the Otolaryngology Department of the University Hospital of Modena were assessed for eligibility. In total, 42 patients who had had synthetic glue application on surgical incisions (A) and 47 patients who had subcuticular sutures on their surgical incisions (B) were enrolled. The mean of the endpoint (based on the Wound Registry Scale) of group A at 10 days was 1.4, while that in group B (based on the Stony Brook Scar Evaluation Scale) was 2.9. Statistically significant (p = 0.002) and clinically significant (difference of the means = 1.5) differences in the aesthetic results were found between groups A and B at 10 days, with better results in group B. On the other hand, at 3 months, the mean of the endpoint in group A was 3.1 while that in group B was 2.8; no statistically significant (p = 0.62) or clinically significant (difference in means = 0.3) differences were found between groups A and B. In conclusion, synthetic glue differs from subcuticular suture in post-thyroidectomy or post-parathyroidectomy incision for early aesthetic results, with better outcomes for subcuticular sutures. At 3 months, there were no differences in aesthetic outcomes between groups. Moreover, sex, incision length, age, cold/hot blade and correspondence of the incision with a wrinkle in the skin did not seem to influence aesthetic outcomes with this type of incision.

Origin of magnetism and quasiparticles properties in Cr-doped TiO2.

Combining the local spin density approximation (LSDA)+U and an analysis of superexchange interactions beyond density functional theory, we describe the magnetic ground state of Cr-doped TiO2, an intensively studied and debated dilute magnetic oxide. In parallel, we correct our LSDA+U (+ superexchange) ground state through GW corrections (GW@LSDA+U) that reproduce the position of the impurity states and the band gaps in satisfying agreement with experiments. Because of the different topological coordinations of Cr-Cr bonds in the ground states of rutile and anatase, superexchange interactions induce either ferromagnetic or antiferromagnetic couplings of Cr ions. In Cr-doped anatase, this interaction leads to a new mechanism which stabilizes a (nonrobust) ferromagnetic ground state, in keeping with experimental evidence, without the need to invoke F-center exchange. The interplay between structural defects and vacancies in contributing to the superexchange is also unveiled.

Origin of the pre-peak features in the oxygen K-edge x-ray absorption spectra of LaFeO3 and LaMnO3 studied by Ga substitution of the transition metal ion.

We report on experimental oxygen K-edge x-ray absorption near edge structure (XANES) spectra of the LaFe(1 - x)Ga(x)O(3) and LaMn(1 - x)Ga(x)O(3) series. Transition metal substitution by the 3d full shell Ga atom is mainly reflected in a systematic decrease of the pre-edge structures in the XANES spectra of the two series. This result shows that the associated states originate from the hybridization of oxygen 2p and unoccupied Fe (or Mn) 3d states. In order to gain insight into the states associated with the pre-edge spectral features, we have performed ab initio theoretical calculations based on multiple scattering theory. Simulations with variable cluster size and composition around the absorber oxygen in the LaFeO(3) and LaMnO(3) crystal structures were carried out. We find that the low-energy pre-peak is reproduced once the absorbing oxygen and the two nearest neighbour Fe (or Mn) ions are considered in the cluster. Conversely, higher energy pre-peaks only arise when the full oxygen coordination geometry around the two metal sites is taken into account, implying that their energy distance is a reflection of the strength of the oxygen ligand field. Substitutions of the two nearest neighbours by Ga atoms in the cluster of calculation lead to changes in the theoretical spectra that reasonably agree with the evolution of the pre-peaks in the experimental XANES spectra of both the series.

Cost-effectiveness analysis of topical treatments for actinic keratosis in the perspective of the Italian health care system.

Actinic keratosis (AK) is the most common cutaneous malignant neoplasm and its prevalence continues to increase. According to the most recent findings, AK is currently considered the initial stage, in situ, of squamous cell carcinoma. Field-directed therapies for AKs are the preferred treatment since they have the advantage to clear the clinically visible lesions and also subclinical lesions within the cancerous field. We assessed the cost-effectiveness of topical treatments for AKs including 3% diclofenac in 2.5% hyaluronic acid (HA) gel, imiquimod 5% cream and photodynamic therapy with methyl aminolevulinate (MAL-PDT) in the perspective of the Italian Health Care System (SSN). We used a decision tree analytical approach and efficacy data were drawn from published clinical trials. Cost was evaluated from the SSN perspective during a time horizon of 3 months. A responder was defined as a patient with all lesions clinically cleared and showing an excellent cosmetic result. Based on the applied model, the cost per complete responder was calculated. Diclofenac 3% in HA was less expensive (Euro 256) than MAL-PDT (Euro 320) and imiquimod (Euro 342). Effectiveness was similar and better for diclofenac 3% in HA and MAL-PDT (0.813%) in comparison to 0.734% of imiquimod, respectively. The one-way and probabilistic sensitivity analyses confirmed the results of base case scenario. Based on this cost-effectiveness model, diclofenac 3% in HA can be considered the treatment of choice for AK lesions and surrounding field under a pharmacoeconomic point of view.

Antiferromagnetic-paramagnetic insulating transition in Cr-doped V(2)O(3) investigated by EXAFS analysis.

We have performed extended x-ray absorption fine-structure (EXAFS) spectroscopy on a 2.8% Cr-doped V(2)O(3) sample, with the aim of studying its structural evolution in a wide temperature range across the paramagnetic-antiferromagnetic insulating phase transition at T(c). The data were registered with two different set-ups in fluorescence and transmission geometries, for polarized and unpolarized spectra, respectively. Our idea, based on previous experiments reported in the literature, is that extended structural modifications of the nominal trigonal symmetry are present in the paramagnetic insulating phase for several tens of degrees above T(c), involving further-nearest-neighbor vanadium ions. Our data confirm that the paramagnetic insulating phase is not structurally homogeneous in a temperature range of about 30 K around T(c), where local distortions of monoclinic symmetry involving further-nearest neighbors are present. Moreover, the analysis of the absorption profile at Cr K-edge suggests that Cr ions enter the lattice randomly. We finally analyze our findings in light of current theoretical models.

Assessment of acceptability and ease of use of atovaquone/proguanil medication in subjects undergoing malaria prophylaxis.

OBJECTIVE: International travelers from non-endemic areas are at high risk of contracting malaria due to their lack of immunity. Prevention is therefore of outmost importance and is achieved through effective and safe chemoprophylaxis, which reduces the risk of fatal disease. Among the various antimalarial drugs available, the synergistic combination of atovaquone and proguanil (A/P) (Malarone((R)); Glaxo-SmithKline) has proven a valuable option in terms of effective protection against chloroquine and multi-drug resistant falciparum malaria, safety, tolerability, and ease of use, thus favoring compliance. The purpose of the present study was to assess acceptability and ease of use of A/P chemoprophylaxis in a population of employees of the oil industry bound to malarious areas. Particular attention was paid to treatment adherence. METHODS: A survey was conducted on a sample of 700 employees on A/P chemoprophylaxis. Demographic data and specific information on A/P treatment were collected by means of a 16-item questionnaire administered immediately before departure. All questionnaires returned were then entered into a database and statistically analyzed. RESULTS: Both habitual and first-time travelers showed good adherence to A/P chemoprophylactic regimen. In general, only few adverse side-effects were reported, none of which were serious. Travelers with previous experience of other antimalarials stated A/P prophylaxis had proven advantageous due to fewer adverse reactions, better condition of administration, and better sense of protection compared with other available treatments.

Direct determination of the magnetic ground state in the square lattice S = 1/2 antiferromagnet Li2VOSiO4.

Powder neutron diffraction and resonant x-ray scattering measurements from a single crystal have been performed to study the low-temperature state of the 2D frustrated, quantum-Heisenberg system Li2VOSiO4. Both techniques indicate a collinear antiferromagnetic ground state, with propagation vector k=(1 / 2 1 / 2 0), and magnetic moments in the a-b plane. Contrary to previous reports, the ordered moment at 1.44 K, m=0.63(3)micro(B), is very close to the value expected for the square lattice Heisenberg model ( approximately 0.6micro(B)). The magnetic order is three dimensional, with antiferromagnetic a-b layers stacked ferromagnetically along the c axis. Neither x-ray nor neutron diffraction shows evidence for a structural distortion between 1.6 and 10 K.

Valence-bond crystal in a pyrochlore antiferromagnet with orbital degeneracy.

We discuss the ground state of a pyrochlore lattice of threefold orbitally degenerate S=1/2 magnetic ions. We derive an effective spin-orbital Hamiltonian and show that the orbital degrees of freedom can modulate the spin exchange, removing the infinite spin-degeneracy characteristic of pyrochlore structures. The resulting state is a collection of spin-singlet dimers, with a residual degeneracy due to their relative orientation. This latter is lifted by a magnetoelastic interaction, induced in the spin-singlet phase space, that forces a tetragonal distortion. Such a theory provides an explanation for the helical spin-singlet pattern observed in the B spinel MgTi2O4.

Local chiral-symmetry breaking in globally centrosymmetric crystals.

A thorough tensor analysis of the Bragg-forbidden reflection (00.3)(h) in corundum systems having a global center of inversion, such as V2O3 and alpha-Fe2O3, shows that anomalous x-ray resonant diffraction can access chiral properties related to the dipole-quadrupole (E1-E2) channel via an interference with the pure quadrupole-quadrupole (E2-E2) process. This is also confirmed by independent ab initio numerical simulations. In such a way, it becomes possible to detect chiral quantities in systems where dichroic absorption techniques are ineffective.

Blue rubber bleb nevus syndrome and gastrointestinal haemorrhage: which treatment?

PURPOSE: To describe a paediatric case of "Blue Rubber Bleb Nevus Syndrome" (BRBNS) or Bean's syndrome, a rare systemic disorder characterised by cutaneous and gastrointestinal vascular malformations that often lead to overt life-threatening gastrointestinal bleeding or occult blood loss with severe anaemia and iron deficiency. CASE REPORT: A 6-year-old girl with multiple characteristic cutaneous vascular lesions was admitted for a massive rectal bleeding. A few months previously she was endoscopically treated for gastric angiomas which developed into melaena. Preoperative investigations revealed the recurrence of gastric lesions. At laparotomy, more than 25 angiomas of the GI tract were found. Multiple intestinal resections were carried out. RESULTS: No intraoperative or postoperative problems occurred and the girl is completely healthy without further bleeding after a follow-up period of three years. CONCLUSIONS: BRBNS belongs to the group of vascular venous malformations. Most of the time it occurs sporadically, but it can be inherited as an autosomal dominant trait. Recent analysis identified a locus on chromosome 9 responsible for venous malformations. BRBNS patients present typical skin lesions, with some lesions having a rubber-like nipple appearance; the number of skin and GI lesions and the severity of anaemia are correlated. Treatment is dependent on the extent of gut involvement and the severity of the clinical picture. In the absence of massive bleeding, a conservative treatment will be sufficient; otherwise resections are mandatory, but additional lesions may subsequently develop. Management with electrocautery or laser photocoagulation are usually not effective even if some reports recommend them. Pharmacological treatment is useless. Prognosis of BRBNS is unknown.

A multiple-scattering theory of circular and linear dichroism for photoemission and photoabsorption.

A unified treatment of circular dichroism, both natural and magnetic, in (spin-resolved) photoemission and photoabsorption from core levels is given, valid in the many-body case and for extended systems, together with an extension of the formalism to treat linear dichroism. The reduction of this scheme to a one-electron picture in the framework of multiple scattering theory is briefly discussed and shows the intimate connection of the two spectroscopies via a generalized optical theorem. Plausibility arguments are given that in correlated d-band systems screening and relaxation effects are not so drastic as in other cases, due to the autoscreening action of the excited photoelectron, so that the final density of states is much like the initial unperturbed one. It is shown how to exploit this point of view to obtain in favorables cases separated orbital and spin moment radial (surface) distribution maps from dichroic magnetic EXAFS spectra (photoelectron diffraction patterns) related to the ground state. Dichroic natural spectra, both in photoemission and absorption, are shown to be sensitive only to atoms in chiral geometry.

Video-assisted minimally invasive coronary bypass surgery without cardiopulmonary bypass.

BACKGROUND: There is a growing interest in cardiac surgery towards minimally invasive approach to coronary bypass operations without cardiopulmonary bypass. PATIENTS AND METHODS: From March 1995 to March 1997, 41 patients underwent a single left internal mammary artery (LIMA) to the left anterior descending artery (LAD) coronary grafting without cardiopulmonary bypass through a small left anterior thoracotomy (MIDCABG). The mean age was 61.2+/-8.7 years (range 43-77 years), 28 patients. were male (68.2%) and the redo rate was 4.8% (2/41). In all patients the coronary artery disease involved the LAD, which was occluded in seven patients (17.1%). Thirty-eight patients (96.2%) selected for MIDCABG had a monovascular disease on LAD not suitable for percutaneous coronary angioplasty; two (4.8%) a bivascular disease, and one (2.4%) a trivascular disease. Skin incision was performed in the 4th anterior intercostal space from the left parasternal line for a 10.5 cm length on average. The LIMA harvesting was partially video-assisted by thoracoscopy. RESULTS: The LAD temporary occlusion was achieved with two double 5/0 polypropilene round-LAD sutures. The mean LAD ischemic time was 22+/-8 min (range 4-35 min). No thoracotomy procedure was changed into a sternotomy approach. We had one (2.4%) perioperative AMI; two patients (4.8%) were reoperated for bleeding. All patients underwent a postoperative angiographic reinvestigation within 1 month after surgery. All anastomoses were perfectly patent but two (4.8%). One patient was reoperated via a sternotomy access recycling the LIMA graft, the other one underwent successful PTCA. All patients also underwent an early and mid-term (6 months after surgery) echo-Doppler study of the LIMA flow and patency. At follow-up, performed at a mean of 8.7 months (range 1-23) after discharge, all patients were alive; no one experienced recurrence of angina. All patients also performed a mid-term negative treadmill stress test. CONCLUSIONS: MIDCABG is, in selected patients, reliable and safe, and offers encouraging early and mid-term clinical results.