Nanopatterning of oxide 2-dimensional electron systems using low-temperature ion milling

We present a 'top-down' patterning technique based on ion milling performed at low-temperature, for the realization of oxide two-dimensional electron system devices with dimensions down to 160 nm. Using electrical transport and scanning Superconducting QUantum Interference Device measurements we demonstrate that the low-temperature ion milling process does not damage the 2DES properties nor creates oxygen vacancies-related conducting paths in the STO substrate. As opposed to other procedures used to realize oxide 2DES devices, the one we propose gives lateral access to the 2DES along the in-plane directions, finally opening the way to coupling with other materials, including superconductors.

The intracavitary electrocardiography method for tip location of jugular internal vein access device in infants of less than 5 kg: A pilot study

Purpose:

This is a prospective observational study conducted by neonatologists in neonatal intensive care unit from Sant’Anna and San Sebastiano Hospital, Caserta, Italy. The objective of the study is to verify the feasibility of intracavitary electrocardiography method for tip location of central venous access device in infants of less than 5 kg and evaluate the accuracy of the method in comparison with post-procedural echocardiographical verification of the tip position.

Patients and methods:

We enrolled 27 patients weighted between 0.660 and 5 kg, requiring central vascular access. Ultrasound-guided jugular internal vein access was used and after cannulation, we applied the intracavitary electrocardiography for tip location as well as post-procedural echocardiography.

Results:

No significant complication related to intracavitary electrocardiography occurred in the studied infants. The increase in P wave on intracavitary electrocardiography was detected in all cases (27/27). In only one case (false positive), the catheter had the tip out of cavoatrial junction–target zone (to post-procedural echocardiography).

Conclusion:

The intracavitary electrocardiography method for tip location of central venous access device is safe and accurate in infants, as demonstrated by post-procedural comparative echocardiographic controls. As an alternative to echocardiography, not always achievable, the diffusion of intracavitary electrocardiography method could reduce X-ray exposition and complications of a malpositioned tip.

The intracavitary electrocardiography method for positioning the tip of epicutaneous cava catheter in neonates: Pilot study

Purpose:

The neonatologists of Sant’Anna and San Sebastiano Hospital of Caserta have carried out a pilot study investigating the safety, feasibility, and accuracy of intracavitary electrocardiography for neonatal epicutaneous cava catheter tip positioning.

Patients and methods:

We enrolled 39 neonates (1–28 days of postnatal age or correct age lower than 41 weeks) requiring epicutaneous cava catheter in the district of superior vena cava (head–neck or upper limbs). Intracavitary electrocardiography was applicable in 38 neonates.

Results:

No significant complications related to intracavitary electrocardiography occurred in the studied neonates. The increase in P wave on intracavitary electrocardiography was detected in 30 cases. Of the remaining eight cases, six malpositioned catheters tipped out of cavoatrial junction–target zone (chest x-ray and echocardiographical control) and two were false negative (tip located in target zone). The match between intracavitary electrocardiography and x-ray was observed in 29/38 cases, and the same ratio between intracavitary electrocardiography and echocardiography was detected.

Conclusion:

We conclude that the intracavitary electrocardiography method is safe and accurate in neonates as demonstrated in pediatric and adult patients. The applicability of the method is 97% and its feasibility is 79%. The overall accuracy is 76% but it rises to 97% if “peak” P wave is detected.

Efficacy of a new technique - INtubate-RECruit-SURfactant-Extubate - "IN-REC-SUR-E" - in preterm neonates with respiratory distress syndrome: study protocol for a randomized controlled trial

Background

Although beneficial in clinical practice, the INtubate-SURfactant-Extubate (IN-SUR-E) method is not successful in all preterm neonates with respiratory distress syndrome, with a reported failure rate ranging from 19 to 69 %. One of the possible mechanisms responsible for the unsuccessful IN-SUR-E method, requiring subsequent re-intubation and mechanical ventilation, is the inability of the preterm lung to achieve and maintain an “optimal” functional residual capacity. The importance of lung recruitment before surfactant administration has been demonstrated in animal studies showing that recruitment leads to a more homogeneous surfactant distribution within the lungs. Therefore, the aim of this study is to compare the application of a recruitment maneuver using the high-frequency oscillatory ventilation (HFOV) modality just before the surfactant administration followed by rapid extubation (INtubate-RECruit-SURfactant-Extubate: IN-REC-SUR-E) with IN-SUR-E alone in spontaneously breathing preterm infants requiring nasal continuous positive airway pressure (nCPAP) as initial respiratory support and reaching pre-defined CPAP failure criteria.

Methods/design

In this study, 206 spontaneously breathing infants born at 24⁺⁰–27⁺⁶ weeks’ gestation and failing nCPAP during the first 24 h of life, will be randomized to receive an HFOV recruitment maneuver (IN-REC-SUR-E) or no recruitment maneuver (IN-SUR-E) just prior to surfactant administration followed by prompt extubation. The primary outcome is the need for mechanical ventilation within the first 3 days of life. Infants in both groups will be considered to have reached the primary outcome when they are not extubated within 30 min after surfactant administration or when they meet the nCPAP failure criteria after extubation.

Discussion

From all available data no definitive evidence exists about a positive effect of recruitment before surfactant instillation, but a rationale exists for testing the following hypothesis: a lung recruitment maneuver performed with a step-by-step Continuous Distending Pressure increase during High-Frequency Oscillatory Ventilation (and not with a sustained inflation) could have a positive effects in terms of improved surfactant distribution and consequent its major efficacy in preterm newborns with respiratory distress syndrome. This represents our challenge.

Trial registration

ClinicalTrials.gov identifier: NCT02482766. Registered on 1 June 2015.

Magnetic behavior of Ni nanoparticle films produced by two laser irradiations in vacuum

Ni Nanoparticle assembled thin films were prepared using an unconventional approach based on the use of a secondary nanosecond (ns) ultraviolet (UV) laser irradiation interacting with the plume of ablated nanoparticles (NPs) during the femtosecond pulsed laser deposition (fs-PLD). The secondary laser beam determines the reduction of the NPs size and their dispersion by partial vaporization of the NPs during their flight from the target to the substrate. The proper selection of the time delay between fs and ns laser pulses allows the latter to interact selectively with different parts of the NPs plume, controlling, to a certain degree, the reduction of the NPs size and dispersion. Another original effect of the UV laser irradiation is the change in the deposited films topology, due to a reduction of the NP-aggregates density and size, fostering non-uniform dense assemblies of NPs with concentration well above the percolation threshold, with the consequent reduction of the influence of the exchange interactions on the macroscopic magnetic properties. The magnetic behavior of the films prepared using two laser beams with respect to that obtained in the case of fs-PLD only is characterized by higher H(c) values (up to approximately 70%) and a good compromise between the hysteresis loops squareness and moderate exchange interactions, strongly correlated with the NPs topology.

Stepwise behaviour of magnetization temperature dependence in iron nanoparticle assembled films

An unusual stepwise behaviour is reported in the temperature dependence of the zero field cooled magnetization in iron nanoparticle dense films produced by ultra-short pulsed laser deposition assisted by irradiation of nanoparticles with a nanosecond UV laser pulse, appropriately delayed, during their flight from the target to the substrate. This behaviour, induced by the particle system's morphology, characterized by clusters of tightly coupled nanoparticles as well as by some voids between them, is ascribed to the competition between Zeeman energy density, intracluster anisotropy energy density and intercluster exchange energy density. A phenomenological model and Monte Carlo simulations are reported, which support the proposed interpretation.

A novel microdeletion in the IGF2/H19 imprinting centre region defines a recurrent mutation mechanism in familial Beckwith-Wiedemann syndrome

The overgrowth disorder Beckwith–Wiedemann syndrome (BWS) is associated with dysregulation of imprinted genes at chromosome 11p15.5. The molecular defects are heterogeneous but most of the cases are associated with defective DNA methylation at either one of two Imprinting Control Regions (IC1 and IC2) or Uniparental paternal Disomy (UPD) at 11p15.5. In rare cases, the BWS phenotype has been found associated with maternal transmission of IC1 microdeletions. We describe a family with a novel 1.8 kb deletion that is associated with hypermethylation at IC1. The mutation results from recombination between highly homologous sequences containing target sites for the zinc-finger protein CTCF (CTSs). This finding supports the hypothesis that the function of IC1 and the penetrance of the clinical phenotype depend on the spacing of the CTSs resulting from recombination in the mutant allele.

Intravenous magnesium sulphate vs. inhaled nitric oxide for moderate, persistent pulmonary hypertension of the newborn. A Multicentre, retrospective study

We have compared intravenous magnesium sulphate vs. inhaled nitric oxide in the therapy of moderate persistent pulmonary hypertension of the neonate. A retrospective collection of clinical data from 58 neonates was carried out in six neonatal intensive care units of Southern Italy sharing the same operational protocols. In our setting, both drugs were effective in treating moderate persistent pulmonary hypertension of the neonate but nitric oxide (NO) treatment resulted in much faster amelioration of oxygenation index, taken as a marker of the underlying condition. No significant difference was recorded in immediate or long-term complications. We conclude that, wherever NO facilities are not readily available, magnesium sulphate is a safe and cheaper alternative for first-line treatment of moderate persistent pulmonary hypertension of the neonate.

Sol-gel synthesis, characterization and bioactivity of poly(ether-imide)/TiO2 hybrid materials

Novel organic-inorganic hybrid materials were synthesized by the sol-gel method from a multicomponent solution containing titanium butoxide, 6 weight % (wt%) or 12 wt% poly(ether-imide) (PEI), water and chloroform. The structure of the interpenetrating network is realized by hydrogen bonds between the Ti-OH group (H-donator) in the sol-gel intermediate species and the carboxylic group (H-acceptor) in the repeating units of the polymer. By Fourier transform infrared (FTIR) analysis the presence of hydrogen bonds between organic-inorganic components of the hybrid materials were proved. The morphology of the hybrid materials was studied by scanning electron microscopy (SEM). The structure of a molecular level dispersion was disclosed by an atomic force microscope (AFM), pore size distribution and surface measurements. The AFM and SEM analyzes confirmed that the PEI/TiO2 samples can be considered homogenous organic/inorganic hybrid materials because in both the compositions studied the average domains were less than 400 nm in size. The bioactivity of the synthesized hybrid materials was demonstrated by the formation of a layer of hydroxyapatite on the surface of the PEI/TiO2 samples soaked in a fluid simulating the composition of human blood plasma (SBF), demonstrated by SEM and energy dispersive spectroscopy (EDS) microscopy.