Indications and outcome of home high-flow nasal therapy in children, a single-center experience.

High-flow nasal therapy (HFNT) is a safe and simple way to deliver humidified air and oxygen for respiratory support in infants and children. HFNT is well established in an inpatient setting, but home HFNT lacks evidence. In the current study, we studied characteristics and outcomes of pediatric patients with home HFNT. In a monocentric retrospective analysis of data for 10 years (April 2010-April 2020), patient characteristics from the time point of the first discharge from hospital with home HFNT-treatment and the subsequent course were analyzed. Patients were divided into three HFNT indication groups: (1) bronchopulmonary dysplasia (BPD), (2) upper airway obstruction (UAO), and (3) other indications. Forty patients received home HFNT in the study period. Seventeen patients were treated for BPD, 15 for UAO, and 8 had other indications. Twenty-two patients (55%) were successfully weaned from HFNT (12 [70.6%] BPD, 7 [46.7%] UAO, 3 [37.5%] other), while seven patients (17.5%) died during follow-up (4 BPD, 2 UAO, 1 other). Twenty-three patients (57.5%) required (intermittent) additional oxygen application (14 [82.4%] BPD, 6 [40%] UAO, 4 [50%] other). Weaning success and need for additional oxygen were significantly more probable in BPD patients compared to the UOA group. In conclusion, HFNT plays an increasing role in home treatment of respiratory insufficiency of various etiologies in childhood. It often represents a temporary intervention, especially for children with BPD but might also serve as long-term treatment for children in whom other forms of ventilatory support are not feasible or desired.

A study on the influence of ligand variation on formamidinate complexes of yttrium: new precursors for atomic layer deposition of yttrium oxide.

The synthesis and characterization of a series of closely related Y(III) compounds comprising the formamidinate ligands (RNCHNR) (R = alkyl) is reported, with the scope of using them as prospective precursors for atomic layer deposition (ALD) of yttrium oxide (Y2O3) thin films. The influence of the side chain variation on the thermal properties of the resulting complexes is studied and benchmarked by thermal analysis and vapor pressure measurements. Density functional theory (DFT) studies give theoretical insights into the reactivity of the compounds towards water, which was targeted as a co-reactant for the deposition of Y2O3via thermal ALD in the next step. Among the four complexes analyzed, tris(N,N'-di-tert-butyl-formamidinato)yttrium(III) [Y(tBu2-famd)3] 1 was found to possess enhanced thermal stability and was selected for Y2O3 ALD process development. A broad ALD window ranging from 200 °C to 325 °C was obtained, yielding films of high compositional quality. Furthermore, with a film density of (4.95 ± 0.05) g cm-1 close to the bulk value, polycrystalline fcc Y2O3 layers with a smooth topography resulted in promising dielectric properties when implemented in metal insulator semiconductor (MIS) capacitor structures.

Atomic layer deposition of dielectric Y2O3 thin films from a homoleptic yttrium formamidinate precursor and water.

We report the application of tris(N,N'-diisopropyl-formamidinato)yttrium(iii) [Y(DPfAMD)3] as a promising precursor in a water-assisted thermal atomic layer deposition (ALD) process for the fabrication of high quality Y2O3 thin films in a wide temperature range of 150 °C to 325 °C. This precursor exhibits distinct advantages such as improved chemical and thermal stability over the existing Y2O3 ALD precursors including the homoleptic and closely related yttrium tris-amidinate [Y(DPAMD)3] and tris-guanidinate [Y(DPDMG)3], leading to excellent thin film characteristics. Smooth, homogeneous, and polycrystalline (fcc) Y2O3 thin films were deposited at 300 °C with a growth rate of 1.36 Å per cycle. At this temperature, contamination levels of C and N were under the detectable limits of nuclear reaction analysis (NRA), while X-ray photoelectron spectroscopy (XPS) measurements confirmed the high purity and stoichiometry of the thin films. From the electrical characterization of metal-insulator-semiconductor (MIS) devices, a permittivity of 13.9 at 1 MHz could be obtained, while the electric breakdown field is in the range of 4.2 and 6.1 MV cm-1. Furthermore, an interface trap density of 1.25 × 1011 cm-2 and low leakage current density around 10-7 A cm-2 at 2 MV cm-1 are determined, which satisfies the requirements of gate oxides for complementary metal-oxide-semiconductor (CMOS) based applications.

Home Noninvasive Ventilation in Pediatric Subjects With Neuromuscular Diseases: One Size Fits All.

BACKGROUND: Home noninvasive ventilation (NIV) improves disease courses of patients with respiratory insufficiency due to neuromuscular diseases. Data about appropriate ventilator settings for pediatric patients are missing. METHODS: In this retrospective study, ventilator settings of 128 subjects with neuromuscular disease aged 0-17 y with NIV were compared between 4 age groups (< 1 y, 0-5 y, 6-11 y, and 12-17 y). Additionally, correlations of ventilator settings with age and vital capacity were investigated in an ungrouped approach. RESULTS: Ventilator backup rate decreased significantly with age, leading to significant backup rate differences between all groups except the oldest two. Median (interquartile range) backup rates were 36 (11.5), 24 (4), 20 (4), and 20 (3) breaths/min in groups 1-4, respectively. Median [IQR] expiratory positive airway pressures (4 [0.5], 4 [0], 4 [0], 4 [1] cm H2O, respectively) and median [IQR] inspiratory positive airway pressures (12 [1.5], 12 [5], 12 [2.3], and 14 [4] cm H2O, respectively) showed no significant differences. However, correlation analyses indicated an increase of inspiratory positive airway pressure with age and decreasing FVC, as well as an increase of backup rates with decreasing FVC. CONCLUSIONS: Similar NIV settings fit all age groups of pediatric subjects with neuromuscular disease. Thus, we propose an expiratory positive airway pressure of 4-5 cm H2O, an inspiratory pressure delta of 8-10 cm H2O, and an age-oriented backup rate as a starting point for NIV titration. Patients with advanced disease stages might require slightly higher inspiratory positive airway pressures and backup rates.

From Precursor Chemistry to Gas Sensors: Plasma-Enhanced Atomic Layer Deposition Process Engineering for Zinc Oxide Layers from a Nonpyrophoric Zinc Precursor for Gas Barrier and Sensor Applications.

The identification of bis-3-(N,N-dimethylamino)propyl zinc ([Zn(DMP)2 ], BDMPZ) as a safe and potential alternative to the highly pyrophoric diethyl zinc (DEZ) as atomic layer deposition (ALD) precursor for ZnO thin films is reported. Owing to the intramolecular stabilization, BDMPZ is a thermally stable, volatile, nonpyrophoric solid compound, however, it possesses a high reactivity due to the presence of Zn-C and Zn-N bonds in this complex. Employing this precursor, a new oxygen plasma enhanced (PE)ALD process in the deposition temperature range of 60 and 160 °C is developed. The resulting ZnO thin films are uniform, smooth, stoichiometric, and highly transparent. The deposition on polyethylene terephthalate (PET) at 60 °C results in dense and compact ZnO layers for a thickness as low as 7.5 nm with encouraging oxygen transmission rates (OTR) compared to the bare PET substrates. As a representative application of the ZnO layers, the gas sensing properties are investigated. A high response toward NO2 is observed without cross-sensitivities against NH3 and CO. Thus, the new PEALD process employing BDMPZ has the potential to be a safe substitute to the commonly used DEZ processes.

PEALD of HfO2 Thin Films: Precursor Tuning and a New Near-Ambient-Pressure XPS Approach to in Situ Examination of Thin-Film Surfaces Exposed to Reactive Gases.

A bottom-up approach starting with the development of new Hf precursors for plasma-enhanced atomic layer deposition (PEALD) processes for HfO2 followed by in situ thin-film surface characterization of HfO2 upon exposure to reactive gases via near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS) is reported. The stability of thin films under simulated operational conditions is assessed, and the successful implementation of HfO2 dielectric layers in metal-insulator-semiconductor (MIS) capacitors is demonstrated. Among the series of newly synthesized mono-guanidinato-tris-dialkyl-amido class of Hf precursors, one of them, namely, [Hf{η2-(iPrN)2CNEtMe}(NEtMe)3], was representatively utilized with oxygen plasma, resulting in a highly promising low-temperature PEALD process at 60 °C. The new precursors were synthesized in the multigram scale and thoroughly characterized by thermogravimetric analyses, revealing high and tunable volatility reflected by appreciable vapor pressures and accompanied by thermal stability. Typical ALD growth characteristics in terms of linearity, saturation, and a broad ALD window with constant growth of 1.06 Å cycle-1 in the temperature range of 60-240 °C render this process very promising for fabricating high-purity smooth HfO2 layers. For the first time, NAP-XPS surface studies on selected HfO2 layers are reported upon exposure to reactive H2, O2, and H2O atmospheres at temperatures of up to 500 °C revealing remarkable stability against degradation. This can be attributed to the absence of surface defects and vacancies. On the basis of these promising results, PEALD-grown HfO2 films were used as dielectric layers in the MIS capacitor device fabrication exhibiting leakage current densities less than 10-7 A cm-2 at 2 MV cm-1 and permittivities of up to 13.9 without postannealing.

Reducing the frequency of respiratory tract infections in severe neurological disorders by inhaled antibiotics: a retrospective data analysis.

BACKGROUND: In patients with severe neurological impairment, recurrent respiratory tract infections frequently occur as a result of impaired clearance of airway secretions and microbial airway colonisation. We hypothesised that inhaled antibiotic therapy may improve the morbidity of these patients. METHODS: A retrospective data analysis of 20 patients (11 nontracheotomised and nine tracheotomised) with neurological impairment and microbial airway colonisation was carried out at a children's university hospital. Two questionnaires that asked about the number of respiratory tract infections, antibiotic therapies and hospitalisations were distributed to the patients/caregivers: a first questionnaire representing the 12 months prior to the initiation of inhaled antibiotics and a second questionnaire describing the first 12 months under therapy. RESULTS: During the first 12 months of therapy, the frequency of respiratory tract infections among all participants was reduced from a mean of 6.8 episodes (median (interquartile range (IQR)) 6.0 (4.0-10.0) episodes) to a mean of 2.5 episodes (median (IQR) 2.0 (1.0-3.0) episodes; p<0.001). In addition, a significant decrease of systemic antibiotic therapies (mean 7.7, median (IQR) 6.0 (4.0-10.0) versus 2.5, 2.5 (0.0-3.75) episodes; p<0.001) and hospitalisations (mean 3.9, median (IQR) 3.5 (1.0-5.0) versus 0.9, 0.0 (0.0-1.0) episodes; p<0.001) was noted. This significant therapeutic effect could be demonstrated in a subgroup analysis in both tracheotomised and nontracheotomised subjects. The reduction of respiratory tract infections and systemic antibiotic therapies (and thus the therapeutic success) was significantly greater in the nontracheotomised group compared with the tracheotomised group. CONCLUSIONS: The presented data suggest that inhaled antibiotics might play a role in treating recurrent respiratory tract infections in neuromuscular diseases.

Low-Temperature Plasma-Enhanced Atomic Layer Deposition of Tin(IV) Oxide from a Functionalized Alkyl Precursor: Fabrication and Evaluation of SnO2-Based Thin-Film Transistor Devices.

A bottom-up process from precursor development for tin to plasma-enhanced atomic layer deposition (PEALD) for tin(IV) oxide and its successful implementation in a working thin-film transistor device is reported. PEALD of tin(IV) oxide thin films at low temperatures down to 60 °C employing tetrakis-(dimethylamino)propyl tin(IV) [Sn(DMP)4] and oxygen plasma is demonstrated. The liquid precursor has been synthesized and thoroughly characterized with thermogravimetric analyses, revealing sufficient volatility and long-term thermal stability. [Sn(DMP)4] demonstrates typical saturation behavior and constant growth rates of 0.27 or 0.42 Å cycle-1 at 150 and 60 °C, respectively, in PEALD experiments. Within the ALD regime, the films are smooth, uniform, and of high purity. On the basis of these promising features, the PEALD process was optimized wherein a 6 nm thick tin oxide channel material layer deposited at 60 °C was applied in bottom-contact bottom-gate thin-film transistors, showing a remarkable on/off ratio of 107 and field-effect mobility of µFE ≈ 12 cm2 V-1 s-1 for the as-deposited thin films deposited at such low temperatures.

Water assisted atomic layer deposition of yttrium oxide using tris(N,N'-diisopropyl-2-dimethylamido-guanidinato) yttrium(iii): process development, film characterization and functional properties.

We report a new atomic layer deposition (ALD) process for yttrium oxide (Y2O3) thin films using tris(N,N'-diisopropyl-2-dimethylamido-guanidinato) yttrium(iii) [Y(DPDMG)3] which possesses an optimal reactivity towards water that enabled the growth of high quality thin films. Saturative behavior of the precursor and a constant growth rate of 1.1 Å per cycle confirm the characteristic self-limiting ALD growth in a temperature range from 175 °C to 250 °C. The polycrystalline films in the cubic phase are uniform and smooth with a root mean squared (RMS) roughness of 0.55 nm, while the O/Y ratio of 2.0 reveal oxygen rich layers with low carbon contaminations of around 2 at%. Optical properties determined via UV/Vis measurements revealed the direct optical band gap of 5.56 eV. The valuable intrinsic properties such as a high dielectric constant make Y2O3 a promising candidate in microelectronic applications. Thus the electrical characteristics of the ALD grown layers embedded in a metal insulator semiconductor (MIS) capacitor structure were determined which resulted in a dielectric permittivity of 11, low leakage current density (≈10-7 A cm-2 at 2 MV cm-1) and high electrical breakdown fields (4.0-7.5 MV cm-1). These promising results demonstrate the potential of the new and simple Y2O3 ALD process for gate oxide applications.

Ultrawide electrical tuning of light matter interaction in a high electron mobility transistor structure.

The interaction between intersubband resonances (ISRs) and metamaterial microcavities constitutes a strongly coupled system where new resonances form that depend on the coupling strength. Here we present experimental evidence of strong coupling between the cavity resonance of a terahertz metamaterial and the ISR in a high electron mobility transistor (HEMT) structure. The device is electrically switched from an uncoupled to a strongly coupled regime by tuning the ISR with epitaxially grown transparent gate. The asymmetric potential in the HEMT structure enables ultrawide electrical tuning of ISR, which is an order of magnitude higher as compared to an equivalent square well. For a single heterojunction with a triangular confinement, we achieve an avoided splitting of 0.52 THz, which is a significant fraction of the bare intersubband resonance at 2 THz.

High-Quality Solution-Processed Silicon Oxide Gate Dielectric Applied on Indium Oxide Based Thin-Film Transistors.

A silicon oxide gate dielectric was synthesized by a facile sol-gel reaction and applied to solution-processed indium oxide based thin-film transistors (TFTs). The SiOx sol-gel was spin-coated on highly doped silicon substrates and converted to a dense dielectric film with a smooth surface at a maximum processing temperature of T = 350 °C. The synthesis was systematically improved, so that the solution-processed silicon oxide finally achieved comparable break downfield strength (7 MV/cm) and leakage current densities (<10 nA/cm(2) at 1 MV/cm) to thermally grown silicon dioxide (SiO2). The good quality of the dielectric layer was successfully proven in bottom-gate, bottom-contact metal oxide TFTs and compared to reference TFTs with thermally grown SiO2. Both transistor types have field-effect mobility values as high as 28 cm(2)/(Vs) with an on/off current ratio of 10(8), subthreshold swings of 0.30 and 0.37 V/dec, respectively, and a threshold voltage close to zero. The good device performance could be attributed to the smooth dielectric/semiconductor interface and low interface trap density. Thus, the sol-gel-derived SiO2 is a promising candidate for a high-quality dielectric layer on many substrates and high-performance large-area applications.

Influence of structural properties on ballistic transport in nanoscale epitaxial graphene cross junctions.

In this paper we investigate the influence of material and device properties on the ballistic transport in epitaxial monolayer graphene and epitaxial quasi-free-standing monolayer graphene. Our studies comprise (a) magneto-transport in two-dimensional (2D) Hall bars, (b) temperature- and magnetic-field-dependent bend resistance of unaligned and step-edge-aligned orthogonal cross junctions, and (c) the influence of the lead width of the cross junctions on ballistic transport. We found that ballistic transport is highly sensitive to scattering at the step edges of the silicon carbide substrate. A suppression of the ballistic transport is observed if the lead width of the cross junction is reduced from 50 nm to 30 nm. In a 50 nm wide device prepared on quasi-free-standing graphene we observe a gradual transition from the ballistic into the diffusive transport regime if the temperature is increased from 4.2 to about 50 K, although 2D Hall bars show a temperature-independent mobility. Thus, in 1D devices additional temperature-dependent scattering mechanisms play a pivotal role.

Matrix-comprehensive in-house validation and robustness check of a confirmatory method for the determination of four nitrofuran metabolites in poultry muscle and shrimp by LC-MS/MS.

An already well-described method for the determination of nitrofuran metabolites 3-amino-5-methyl-morpholino-2-oxazolidinone (AMOZ), 3-amino-2-oxazolidinone (AOZ), semicarbazide (SEM) and 1-aminohydantoin (AHD) was adapted to the needs of our laboratory and checked for its robustness regarding sample conditions and the processing step. Using the same data, the method was validated and the measurement uncertainty was estimated. All criteria and requirements of Commission Decision 2002/657/EC were fulfilled. The CC(alpha) determined lies between 0.1 and 0.7 microg/kg, the CC(beta) lies between 0.1 and 0.9 microg/kg, the measurement uncertainty was estimated as being between 7 and 17% taking into account matrix, time and sample preparation influences.

Phytoremediation to increase the degradation of PCBs and PCDD/Fs. Potential and limitations.

Phytoremediation is already regarded as an efficient technique to remove or degrade various pollutants in soils, water and sediments. However, hydrophobic organic molecules such as PAHs, PCBs and PCDD/Fs are much less responsive to bioremediation strategies than, for example, BTEX or LAS. PCDD/Fs and PCBs represent 3 prominent groups of persistent organic pollutants that share common chemical, toxicological and environmental properties. Their widespread presence in the environment may be explained by their chemical and biological stability. This review considers their fate and dissipation mechanisms. It is then possible to identify major sinks and to understand biological activities useful for remediation. Public health and economic priorities lead to the conclusion that alternative techniques to physical treatments are required. This review focuses on particular problems encountered in biodegradation and bioavailability of PCDD/Fs and PCBs. It highlights the potential and limitations of plants and micro-organisms as bioremediation agents and summarises how plants can be used to augment bacterial activity. Phytoremediation is shown to provide some new possibilities in reducing risks associated with dioxins and PCBs.