Spin-lattice relaxation time in water/graphene-oxide dispersion.

We present the results of the calculations of the spin-lattice relaxation time of water in contact with graphene oxide by means of all-atom molecular dynamics simulations. We fully characterized the water-graphene oxide interaction through the calculation of the relaxation properties of bulk water and of the contact angle as a function of graphene oxide oxidation state and comparing them with the available experimental data. We then extended the calculation to investigate how graphene oxide alters the dynamical and relaxation properties of water in different conditions and concentrations. We show that, despite the diamagnetic nature of the graphene oxide, the confining effects of the bilayers strongly affect the longitudinal relaxation properties of interfacial water, which presents a reduced dynamics due to hydrogen bonds with oxygen groups on graphene oxide. This property makes graphene oxide an interesting platform to investigate water dynamics in confined geometries and an alternative contrast-agent for magnetic resonance imaging applications, especially in view of the possibility to functionalize graphene oxide from theranostic perspectives.

Chiral Spin Texture in the Charge-Density-Wave Phase of the Correlated Metallic Pb/Si(111) Monolayer.

We investigate the 1/3 monolayer α-Pb/Si(111) surface by scanning tunneling spectroscopy (STS) and fully relativistic first-principles calculations. We study both the high-temperature sqrt[3]×sqrt[3] and low-temperature 3×3 reconstructions and show that, in both phases, the spin-orbit interaction leads to an energy splitting as large as 25% of the valence-band bandwidth. Relativistic effects, electronic correlations, and Pb-substrate interaction cooperate to stabilize a correlated low-temperature paramagnetic phase with well-developed lower and upper Hubbard bands coexisting with 3×3 periodicity. By comparing the Fourier transform of STS conductance maps at the Fermi level with calculated quasiparticle interference from nonmagnetic impurities, we demonstrate the occurrence of two large hexagonal Fermi sheets with in-plane spin polarizations and opposite helicities.

Sexual Developmental Disorders in Pediatrics.

Abstract: Disorders of sex development (DSD) are a heterogeneous group of pathologies that result in an alteration in sex determination or differentiation. DSD are estimated to affect 1: 4,500 newborns and according to the 2006 Chicago Consensus classification, DSD can be divided into three categories: those with a 46 XX karyotype, those with a 46 XY karyotype and those relating to sex chromosomes. It is crucial to correctly identify the pathology already in the first days of life to direct the patient and his family to the best path of care. For this reason, the role of the pediatrician is fundamental in the correct identification of the clinical picture and in supporting the family during the long process that involves the management of these patients. To make a diagnosis, it is necessary to follow a path led by a multidisciplinary team that includes several steps such as the execution of the genetic analysis, the evaluation with diagnostic imaging methods and laboratory evaluations. The therapeutic management, on the other hand, is still very complex even if in recent years we have moved from an attitude of early gender reassignment to an approach of watchful waiting to let the patient choose when she/he is mature enough to do so, which gender she/he feels to belong. It should not be forgotten that throughout this process the pediatrician must be both supportive and clinically active in the management of the child and his family.

Simulation-based design study for the passive shielding of the COSINUS dark matter experiment.

The COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches) experiment aims at the detection of dark matter-induced recoils in sodium iodide (NaI) crystals operated as scintillating cryogenic calorimeters. The detection of both scintillation light and phonons allows performing an event-by-event signal to background discrimination, thus enhancing the sensitivity of the experiment. The choice of using NaI crystals is motivated by the goal of probing the long-standing DAMA/LIBRA results using the same target material. The construction of the experimental facility is foreseen to start by 2021 at the INFN Gran Sasso National Laboratory (LNGS) in Italy. It consists of a cryostat housing the target crystals shielded from the external radioactivity by a water tank acting, at the same time, as an active veto against cosmic ray-induced events. Taking into account both environmental radioactivity and intrinsic contamination of materials used for cryostat, shielding and infrastructure, we performed a careful background budget estimation. The goal is to evaluate the number of events that could mimic or interfere with signal detection while optimising the geometry of the experimental setup. In this paper we present the results of the detailed Monte Carlo simulations we performed, together with the final design of the setup that minimises the residual amount of background particles reaching the detector volume.

Retention of the tetragonal to orthorhombic structural transition in F-substituted SmFeAsO: a new phase diagram for SmFeAs(O(1-x)F(x)).

In this Letter we propose a new phase diagram for the SmFeAs(O(1-x)F(x)) system, based on careful analysis of synchrotron powder diffraction data, SQUID, and muon spin rotation measurements. The tetragonal to orthorhombic structural transition is slightly affected by F content and is retained for the superconducting samples, even at optimal doping. These findings relate the AFM transition on a different ground with respect to the structural one and suggests that orbital ordering could be the driving force for symmetry breaking.

Multiband superconductivity in Pb, H under pressure and CaBeSi from ab initio calculations.

Superconductivity in Pb, H under extreme pressure and CaBeSi, in the framework of the density functional theory for superconductors, is discussed. A detailed analysis on how the electron-phonon and electron-electron interactions combine together to determine the superconducting gap and critical temperature of these systems is presented. Pb, H under pressure and CaBeSi are multigap superconductors. We will address the question under which conditions does a system exhibits this phenomenon. The presented results contribute to the understanding of multiband and anisotropic superconductivity, which has received a lot of attention since the discovery of MgB(2), and show how it is possible to describe the superconducting properties of real materials on a fully ab initio basis.

Fermi-Surface Topological Phase Transition and Horizontal Order-Parameter Nodes in CaFe2As2 Under Pressure.

Iron-based compounds (IBS) display a surprising variety of superconducting properties that seems to arise from the strong sensitivity of these systems to tiny details of the lattice structure. In this respect, systems that become superconducting under pressure, like CaFe2As2, are of particular interest. Here we report on the first directional point-contact Andreev-reflection spectroscopy (PCARS) measurements on CaFe2As2 crystals under quasi-hydrostatic pressure, and on the interpretation of the results using a 3D model for Andreev reflection combined with ab-initio calculations of the Fermi surface (within the density functional theory) and of the order parameter symmetry (within a random-phase-approximation approach in a ten-orbital model). The almost perfect agreement between PCARS results at different pressures and theoretical predictions highlights the intimate connection between the changes in the lattice structure, a topological transition in the holelike Fermi surface sheet, and the emergence on the same sheet of an order parameter with a horizontal node line.

Atomically precise semiconductor--graphene and hBN interfaces by Ge intercalation.

The full exploration of the potential, which graphene offers to nanoelectronics requires its integration into semiconductor technology. So far the real-world applications are limited by the ability to concomitantly achieve large single-crystalline domains on dielectrics and semiconductors and to tailor the interfaces between them. Here we show a new direct bottom-up method for the fabrication of high-quality atomically precise interfaces between 2D materials, like graphene and hexagonal boron nitride (hBN), and classical semiconductor via Ge intercalation. Using angle-resolved photoemission spectroscopy and complementary DFT modelling we observed for the first time that epitaxially grown graphene with the Ge monolayer underneath demonstrates Dirac Fermions unaffected by the substrate as well as an unperturbed electronic band structure of hBN. This approach provides the intrinsic relativistic 2D electron gas towards integration in semiconductor technology. Hence, these new interfaces are a promising path for the integration of graphene and hBN into state-of-the-art semiconductor technology.

Laser-assisted versus mechanical recanalization of femoral arterial occlusions.

A randomized clinical trial was performed to test the hypothesis that a laser-heated probe is superior to standard techniques to reopen occluded femoral arteries. Twenty patients were treated with a standard guidewire and balloon dilation method. In a second group of 20 patients, the laser probe was initially used as a nonheated mechanical device. If the probe was unsuccessful in mechanically reopening the artery, an Argon laser was activated to heat the probe. The mean length of occlusion was 15.9 +/- 10.3 cm. The success rate for the laser probe was 15 of 20 (75%), which was not significantly different from the standard method, 19 of 20 (95%). Most of the success in the laser-probe group was due to the probe's mechanical properties. The laser probe was successful as a cold, mechanical device in 13 of 15 (87%) arteries. It was necessary to heat the probe in 5 patients. When heated, the laser probe assisted recanalization in 2 but perforated the artery in 3 cases. The results of this randomized trial do not support the hypotheses behind the use of the thermal laser probe. The laser probe functions primarily as a mechanical device. The thermal activation does not significantly improve the success rate without increasing the risk of perforation. This small additional benefit does not justify the large cost of current thermal laser devices. This controlled study also demonstrates a higher success rate in long occlusions than previous reports of mechanical balloon recanalization. This is due to a combination approach of retrograde and anterograde probing of the occluded segment.

Lung cancer in patients with immunodeficiency syndrome.

We report adenocarcinoma of the lung in seven patients with human immunodeficiency virus (HIV) infection. We compared age, clinical findings and survival data with a sex-matched control group of HIV-negative patients with adenocarcinoma of the lung. Median age of HIV-infected patients with lung cancer was lower than in control patients with lung cancer. The HIV-infected patients had more systemic symptoms and abnormal physical findings than control subjects. Both groups had smoking histories. Laboratory data were similar but control subjects had lower blood oxygen tensions than did HIV patients; HIV patients had more abnormalities on chest roentgenograms and computed tomography scans than did control subjects. All HIV-infected patients were stage IV. Median survival was 4 weeks. For control patients, 50 percent had stage IV disease; median survival was 25.5 weeks. Thus, patients with HIV infection develop lung cancer at a younger age than sex-matched control subjects and undergo a more fulminant course with shortened survivals.

A new instrumentation system for the reduction and posterior stabilization of unstable thoracolumbar fractures.

An innovative instrumentation and stabilization system was used for the treatment of unstable thoracolumbar fractures. The new osteosynthesis apparatus employs pedicle screw fixation, plate application, and a mechanical device for dynamic reduction in stable posterior fixation. Sixteen patients were treated with this operative technique that included a decompressive laminectomy, an arthropedunculectomy, and the removal of vertebral canal bone fragments. In most patients, three vertebral bodies, rather than four or five, were immobilized. All patients were studied pre- and postoperatively with plain radiographs and computed tomography. Pre- and postoperative examinations demonstrated no alteration in neurological status. All patients, however, with incomplete lesions showed improvement in neurological function at a mean follow-up period of 12 months. The authors' experience suggests that the new system offers ease and versatility of application, restoration of vertebral alignment through mechanical reduction, and enhanced spinal stability. The new system, moreover, enables the reduction of lateral dislocation.

Terminal ventriculostomy for syringomyelia.

The pathogenesis of syringomylia is not yet well known and its surgical management still poses problems. Terminal ventriculostomy, as proposed by Gardner et al. (1977), in treating the communicating syringomyelia could be an alternative approach as opposed to the cranio-vertebral decompression or subarachnoid shunt of the syrinx. This operation was performed by the authors in 3 cases. In all of them there was postoperative improvement of the neurological symptoms. In the authors' opinion the main problem is the difficulty in preoperative diagnosis of communicating syringomyelia. This technique is simple and could present an efficient means of diagnosing the communicating syringomyelia, particularly when there are no associated malformations.

Transcranial Doppler ultrasound. Examination technique and normal reference values.

A newly developed Transcranial Doppler system (TCD) has been used in a group of subjects without any cerebrovascular disease (CVD) in order to establish the standard criteria for transcranial basal cerebral arteries examination and settle normal velocimetric and hemodynamic parameters. TCD examination in patients suffering from CVD provides useful information for clinical management of such pathological conditions.

"Ultraearly" aneurysm surgery.

Three hundred and twenty-seven patients with intracranial aneurysm were managed at the Neurosurgical Division of Emergency Department of the Cardarelli Hospital of Naples. Of the 327 patient, 231 (70.6%), (I group), were operated on after 72 hours and 96 patients (29.4%), (II group), were operated on within 72 hours of subaracnoid hemorrhage. The patients operated on within 72 hours of hemorrhage (II group) were divided in two subgroups: 29 patients operated on within 72 hours formed the IIa group ("ultraearly" surgery) and 67 patients operated on between 24-72 hours formed the IIb group. Poor clinical grades (IV and V Hunt and Hess grades) were excluded from this study. Glasgow outcome scale (GOS), simplified in three grades was used to evaluate the results (GOS 1 good recovery; GOS 2 moderate or severe disability, and GOS 3 dead). The outcome was evaluated at the dimission and at 6 months. The best results seem to be for the patients in group IIb (24-72 hours), but if we consider that 31.2% of the patients operated on within 24 hours (IIa group) were in grade III of Hunt and Hess classification, also for these patients the surgical results seem to be good. The clinical presentation, treatment and outcome are discussed in this report.

A new instrumentation for posterior stabilization of cervical traumatic instability.

BACKGROUND: Twenty-six patients underwent application of a new posterior plating system (CIDEF SYSTEM) for the alignment and the stabilization of C3-C7 cervical unstable fractures from January 1992 to December 1993. METHODS: The osteosynthesis apparatus employs posterior articular screw fixation and plate application. Indications for surgery were the presence of neurological damage and cervical column instability. Operative techniques included decompressive and exploratory laminectomy in 20 cases and an articular resection in six cases of posterior superior articular fractures. A one-stage operation with an anterior approach, designed to remove anterior compression from herniated discs, or bone fragments, was also performed in four cases. Three cervical motion segments were immobilized in 15 of the treated cases; four in nine; and five in two. All patients were studied pre- and postoperatively with plain radiographs and computed tomography. Pre- and postoperative examinations demonstrated no alteration in neurological status. RESULTS: At a mean follow-up period of 47 months, no evidence was found of infection, rejection of the materials used, or mechanical failure of the plates and screws; all patients with incomplete lesion showed improvement in neurological function. Four patients tetraplegic at admission expired from systemic complications (one from pulmonary embolism; one from Disseminated Intravascular Coagulopathy; one for sepsis; and one from myocardial infarction). All patients were immobilized for at least 4 months with a Philadelphia collar. No injury to the neural or vascular structures contiguous to the cervical spine has occurred. CONCLUSIONS: The authors' experience suggests that the new system offers ease and versatility of application, restoration of vertebral alignment, enhanced spinal stability and is useful in the treatment of urgent and rather complex traumatic lesions of the lower cervical spine.

Non invasive recording of CO2 cerebrovascular reactivity in normal subjects and patients with unilateral internal carotid artery stenosis.

CO2 cerebrovascular reactivity has been recorded in 12 healthy volunteers and 10 patients with unilateral > 70% extracranial internal carotid artery (ICA) stenosis, using non invasive techniques. The relative changes of middle cerebral artery blood flow velocity (VMCA) and velocity waveform pulsatility (PIMCA) after that hypocapnia was induced by spontaneous hyperventilation were recorded. 35.5% average VMCA reduction and 63% PIMCA increment of basal values was produced in healthy subjects after hyperventilation. The percentage variation of CO2 Reactivity Index (RI), expressed in terms of VMCA (V-RI) and PIMCA (PI-RI), per mmHg change in pCO2, presents a good right-left side correlation (r = 0.82 and r = 0.83 respectively) in healthy subjects, while a dissociation between V-RI and PI-RI was found in our patients. A significant reduction of PI-RI was also recorded in the group of patients on the side of ICA stenosis. From our data CO2 reactivity index recorded in terms of PI seems to allow a better separation between pathology and normality, without the need to assume a close relationship between velocity and blood flow under the condition considered. Furthermore, PI-RI seems to be a valid index in the evaluation of some attribute pertaining to the distal vascular bed.

The postero-lateral approach in the treatment of post-traumatic canalar stenosis of the thoraco-lumbar spine.

METHODS: Twenty-four cases of unstable thoraco-lumbar fractures with significant canalar stenosis were operated in the Emergency Neurosurgical Unit of the Cardarelli Hospital from November 1989 to October 1991. The surgical technique was the combined transpedicular (TPA) and transarticular (TAA) postero-lateral approach, posterior osteosynthesis and arthrodesis. The average follow-up was 20 months. RESULTS: No evidence of implant breakage or pseudoarthrosis was detected. CONCLUSIONS: The authors affirm recalibration of the posterior wall by direct impaction, epidural hemostasis, removal of extruded disc fragments and dural repair are the advantages offered by this technique without compromise the contsrist stability. This approach represents an alternative to single posterior and combined anterior-posterior approaches in the management of the thoraco-lumbar fractures with severe canal stenosis.

Surgical treatment of subdural empyema: a critical review.

Between 1990 and 1992 six cases of subdural empyema were surgically treated at the Neurosurgical Division of Emergency Department of Cardarelli Hospital in Naples. Three cases were associated with paranasal sinusitis and three cases with otitis media. Headache and fever were the presenting symptoms in all cases; in only two cases they were associated with seizures and altered mental status. CT scans showed convexity low density collections in five cases and multilocalized pus collection in one; concurrent paranasal or mastoid infections were visualized as well. The organisms responsible for the subdural empyema were Peptococcus in four cases, Streptococcus and anaerobius in the other two cases. In five cases surgical treatment consists in pus drainage by selective burr hole and placement of a subdural small silicon tube for local antibiotic therapy. In one case with a loculated diffuse empyema, craniotomy was performed in order to provide a better access to all the localizations. In all cases drainage of the wound and intravenous antibiotic therapy were used. Paranasal sinus drainage or mastoidectomy performed by the otolaryngologist when a localized collection of pus was present, grave a quicker regression of symptoms. A full recover of the original neurological status was achieved in all cases; a 20 months mean followup confirms the results.