Evidence for shallow implantation during the growth of bismuth nanocrystals by pulsed laser deposition

The shallow implantation of Bi species was analyzed for energy densities above 2 Jcm-2. The implantation range was shown to depend on the energy density used for ablation, which was related to the velocity of the Bi atoms and ions in the plasma. The kinetic energy of the Bi species in the plume generated at laser energy densities above 2 J cm-2 was estimated to be around 200 eV.This work has been partially supported by project TIC99-0866, CICYT (Spain). One of the authors (J.-P.B.) acknowledges support by the EPSRC and a Marie Curie Fellowship of the EC under Contract No. HPMT-CT-2000-00064.Peer Reviewe

Study protocol: NITric oxide during cardiopulmonary bypass to improve Recovery in Infants with Congenital heart defects (NITRIC trial): a randomised controlled trial

Introduction Congenital heart disease (CHD) is a major cause of infant mortality. Many infants with CHD require corrective surgery with most operations requiring cardiopulmonary bypass (CPB). CPB triggers a systemic inflammatory response which is associated with low cardiac output syndrome (LCOS), postoperative morbidity and mortality. Delivery of nitric oxide (NO) into CPB circuits can provide myocardial protection and reduce bypass-induced inflammation, leading to less LCOS and improved recovery. We hypothesised that using NO during CPB increases ventilator-free days (VFD) (the number of days patients spend alive and free from invasive mechanical ventilation up until day 28) compared with standard care. Here, we describe the NITRIC trial protocol. Methods and analysis The NITRIC trial is a randomised, double-blind, controlled, parallel-group, two-sided superiority trial to be conducted in six paediatric cardiac surgical centres. One thousand three-hundred and twenty infants <2 years of age undergoing cardiac surgery with CPB will be randomly assigned to NO at 20 ppm administered into the CPB oxygenator for the duration of CPB or standard care (no NO) in a 1:1 ratio with stratification by age (<6 and ≥6 weeks), single ventricle physiology (Y/N) and study centre. The primary outcome will be VFD to day 28. Secondary outcomes include a composite of LCOS, need for extracorporeal membrane oxygenation or death within 28 days of surgery; length of stay in intensive care and in hospital; and, healthcare costs. Analyses will be conducted on an intention-to-treat basis. Preplanned secondary analyses will investigate the impact of NO on host inflammatory profiles postsurgery. Ethics and dissemination The study has ethical approval (HREC/17/QRCH/43, dated 26 April 2017), is registered in the Australian New Zealand Clinical Trials Registry (ACTRN12617000821392) and commenced recruitment in July 2017. The primary manuscript will be submitted for publication in a peer-reviewed journal. Trial registration number ACTRN12617000821392.</p

Optical and magneto-optical properties of Fe nanoparticles

The optical and magneto-optical properties of Fe nanoparticles with sizes ranging from 2 to 8 nm, embedded in amorphous Al2O3, are studied as a function of their size and shape. The optical properties were measured using spectroscopic ellipsometry, whereas the magneto-optical properties were determined in two different Kerr configurations: polar and transverse. A generalization of different effective medium approximations is used to describe and analyze experimental data in nanocomposite media. In this generalization, the shapes of the nanoparticles are considered as an input parameter. The optical and magneto-optical parameters show clearly different values as a function of the nanoparticle size. A reasonable agreement between the theoretical calculations and experimental data is found when the average size of the nanoparticles is larger than 4 nm. On the other hand, the experimental and theoretical curves differ for smaller sizes, implying that below 4 nm the optical and magneto-optical constants of the particles deviate from the bulk behavior.J. L. M. wants to acknowledge Comunidad de Madrid’s Consejería de Educación y Cultura for financial support. This work was partially supported by TIC99-0866, MAT98-0974, MAT99-1063, CICYT (Spain).Peer reviewe

Resuscitation With Early Adrenaline Infusion for Children With Septic Shock: A Randomized Pilot Trial

OBJECTIVES: In children with septic shock, guidelines recommend resuscitation with 40–60 mL/kg of fluid boluses, yet there is a lack of evidence to support this practice. We aimed to determine the feasibility of a randomized trial comparing early adrenaline infusion with standard fluid resuscitation in children with septic shock. DESIGN: Open-label parallel randomized controlled, multicenter pilot study. The primary end point was feasibility; the exploratory clinical endpoint was survival free of organ dysfunction by 28 days. SETTING: Four pediatric Emergency Departments in Queensland, Australia. PATIENTS: Children between 28 days and 18 years old with septic shock. INTERVENTIONS: Patients were assigned 1:1 to receive a continuous adrenaline infusion after 20 mL/kg fluid bolus resuscitation (n = 17), or standard care fluid resuscitation defined as delivery of 40 to 60 mL/kg fluid bolus resuscitation prior to inotrope commencement (n = 23). MEASUREMENTS AND MAIN RESULTS: Forty of 58 eligible patients (69%) were consented with a median age of 3.7 years (interquartile range [IQR], 0.9–12.1 yr). The median time from randomization to inotropes was 16 minutes (IQR, 12–26 min) in the intervention group, and 49 minutes (IQR, 29–63 min) in the standard care group. The median amount of fluid delivered during the first 24 hours was 0 mL/kg (IQR, 0–10.0 mL/kg) in the intervention group, and 20.0 mL/kg (14.6–28.6 mL/kg) in the standard group (difference, –20.0; 95% CI, –28.0 to –12.0). The number of days alive and free of organ dysfunction did not differ between the intervention and standard care groups, with a median of 27 days (IQR, 26–27 d) versus 26 days (IQR, 25–27 d). There were no adverse events reported associated with the intervention. CONCLUSIONS: In children with septic shock, a protocol comparing early administration of adrenaline versus standard care achieved separation between the study arms in relation to inotrope and fluid bolus use

Lorentz transmission electron microscopy and magnetic force microscopy characterization of NiFe/Al-oxide/Co films

Magnetization reversal process of NiFe/Al-oxide/Co junction films was observed directly using Lorentztransmission electron microscopy (LTEM) and magnetic force microscopy(MFM).In situmagnetizing experiments performed in both LTEM and MFM were facilitated by a pair of electromagnets, which were mounted on the sample stages. A two-stage magnetization reversal process for the junction film was clearly observed in LTEM with NiFe magnetization reversed first via domain wall motion followed by Co magnetization reversal via moment rotation and domain wall motion. Reversal mechanism and domain characteristics of the NiFe and Co layers showed very distinctive features. The magnetization curve of the junction filmmeasured using alternating gradient force magnetometry showed a nonzero slope at the antiparallel magnetization configuration region, which implies that magnetization directions of the NiFe and Co layers were not exactly antiparallel due to Co moment rotation existed in that region. After the magnetization reversal of the Co was complete, MFM images revealed some magnetic contrast, which suggests that an out-of-plane magnetization component remained in the Co layer. Such magnetic contrast disappeared at higher magnetic fields when the Co moments further rotated and aligned parallel to the applied field direction

Resuscitation With Vitamin C, Hydrocortisone, and Thiamin in Children With Septic Shock: A Multicenter Randomized Pilot Study

OBJECTIVES: Adjunctive therapy with vitamin C, hydrocortisone, and thiamin has been evaluated in adults, but randomized controlled trial (RCT) data in children are lacking. We aimed to test the feasibility of vitamin C, hydrocortisone, and thiamin in PICU patients with septic shock; and to explore whether the intervention is associated with increased survival free of organ dysfunction. DESIGN: Open-label parallel, pilot RCT multicenter study. The primary endpoint was feasibility. Clinical endpoints included survival free of organ dysfunction censored at 28 days and nine secondary outcomes, shock reversal, and two proxy measures of intervention efficacy. SETTING: Six PICUs in Australia and New Zealand. PATIENTS: Children of age between 28 days and 18 years requiring vasoactive drugs for septic shock between August 2019 and March 2021. INTERVENTIONS: Patients were assigned 1:1 to receive 1 mg/kg hydrocortisone every 6 hours (q6h), 30 mg/kg ascorbic acid q6h, and 4 mg/kg thiamin every 12 hours (n = 27), or standard septic shock management (n = 33). MEASUREMENTS AND MAIN RESULTS: Sixty of 77 (78%) eligible patients consented with 91% of approached parents providing consent. The median time from randomization to intervention was 44 (interquartile range [IQR] 29–120) min. Seventy of seventy-seven (28%) patients had received IV steroids before randomization. Median survival alive and free of organ dysfunction was 20.0 (0.0–26.0) days in the intervention and 21.0 (0.0–25.0) days in the standard care group. Median PICU length of stay was 5.3 (2.5–11.3) days in the intervention group versus 6.9 (3.0–11.5) days in the control group. Shock reversal occurred at a median of 35.2 (14.6–101.2) hours in the intervention group versus 47.3 (22.4–106.8) hours in the standard care group (median difference –12 hr; 95% CI, –56.8 to 32.7 hr). CONCLUSIONS: In children requiring vasopressors for septic shock, a protocol comparing adjunctive treatment with high-dose vitamin C, hydrocortisone, and thiamin versus standard care was feasible. These findings assist in making modifications to the trial protocol to enable a better-designed larger RCT

Coexistence of Merons with Skyrmions in the Centrosymmetric van der Waals Ferromagnet Fe5GeTe2

Fe$_{5-x}$GeTe$_2$ is a centrosymmetric, layered van der Waals (vdW) ferromagnet that displays Curie temperatures $T_c$ (270-330 K) that are within the useful range for spintronic applications. However, little is known about the interplay between its topological spin textures (e.g., merons, skyrmions) with technologically relevant transport properties such as the topological Hall effect (THE), or topological thermal transport. Here, we show via high-resolution Lorentz transmission electron microscopy that merons and anti-meron pairs coexist with N\'{e}el skyrmions in Fe$_{5-x}$GeTe$_2$ over a wide range of temperatures and probe their effects on thermal and electrical transport. We detect a THE, even at room $T$, that senses merons at higher $T$s as well as their coexistence with skyrmions as $T$ is lowered indicating an on-demand thermally driven formation of either type of spin texture. Remarkably, we also observe an unconventional THE in absence of Lorentz force and attribute it to the interaction between charge carriers and magnetic field-induced chiral spin textures. Our results expose Fe$_{5-x}$GeTe$_2$ as a promising candidate for the development of applications in skyrmionics/meronics due to the interplay between distinct but coexisting topological magnetic textures and unconventional transport of charge/heat carriers.Comment: In press. Four figures in the main text. Includes SI file with 19 additional figure

Writing and detecting topological charges in exfoliated Fe5−x_{5-x}GeTe2_2

Fe$_{5-x}$GeTe$_2$ is a promising two-dimensional (2D) van der Waals (vdW) magnet for practical applications, given its magnetic properties. These include Curie temperatures above room temperature, and topological spin textures (TST or both merons and skyrmions), responsible for a pronounced anomalous Hall effect (AHE) and its topological counterpart (THE), which can be harvested for spintronics. Here, we show that both the AHE and THE can be amplified considerably by just adjusting the thickness of exfoliated Fe$_{5-x}$GeTe$_2$, with THE becoming observable even in zero magnetic field due to a field-induced unbalance in topological charges. Using a complementary suite of techniques, including electronic transport, Lorentz transmission electron microscopy, and micromagnetic simulations, we reveal the emergence of substantial coercive fields upon exfoliation, which are absent in the bulk, implying thickness-dependent magnetic interactions that affect the TST. We detected a ``magic" thickness $t \sim$30 nm where the formation of TST is maximized, inducing large magnitudes for the topological charge density ($6.45 \times 10^{20}$ cm$^{-2}$), and the concomitant anomalous ($\rho_{xy}^{\text{A,max}} \simeq 22.6$ $\mu \Omega$cm) and topological ($\rho_{xy}^{\text{u,T}} \simeq 15$ $\mu \Omega$ cm) Hall resistivities at $T$ ~ 120 K. These values for $\rho_{xy}^{\text{A,max}}$ and $\rho_{xy}^{\text{u,T}}$ are higher than those found in magnetic topological insulators and, so far, the largest reported for 2D magnets. The hitherto unobserved THE under zero magnetic field could provide a platform for the writing and electrical detection of TST aiming at energy-efficient devices based on vdW ferromagnets.Comment: 45 pages with supporting information file, 5 main figures. Accepted ACS Nano 202

Implementing paediatric appropriate use criteria for endotracheal suction to reduce complications in mechanically ventilated children with respiratory infections

BackgroundEndotracheal suction is used to maintain endotracheal tube patency. There is limited guidance to inform clinical practice for children with respiratory infections.ObjectiveThe objective of this study was to determine whether implementation of a paediatric endotracheal suction appropriate use guideline Paediatric AirWay Suction (PAWS) is associated with an increased use of appropriate and decreased use of inappropriate suction interventions.MethodsA mixed-method, pre-implementation–post-implementation study was conducted between September 2021 and April 2022. Suction episodes in mechanically ventilated children with a respiratory infection were eligible. Using a structured approach, we implemented the PAWS guideline in a single paediatric intensive care unit. Evaluation included clinical (e.g., suction intervention appropriateness), implementation (e.g., acceptability), and cost outcomes (implementation costs). Associations between implementation of the PAWS guideline and appropriateness of endotracheal suction intervention use were investigated using generalised linear models.ResultsData from 439 eligible suctions were included in the analysis. Following PAWS implementation, inappropriate endotracheal tube intervention use reduced from 99% to 58%, an absolute reduction (AR) of 41% (95% confidence interval [CI]: 25%, 56%). Reductions were most notable for open suction systems (AR: 48%; 95% CI: 30%, 65%), 0.9% sodium chloride use (AR: 23%; 95% CI: 8%, 38%) and presuction and postsuction manual bagging (38%; 95% CI: 16%, 60%, and 86%; 95% CI: 73%, 99%), respectively. Clinicians perceived PAWS as acceptable and suitable for use.ConclusionsImplementation of endotracheal tube suction appropriate use guidelines in a mixed paediatric intensive care unit was associated with a large reduction in inappropriate suction intervention use in paediatric patients with respiratory infections