Long-Term Respiratory Support for Children and Adolescents in Austria: A National Survey.

BACKGROUND: Population-based data on pediatric patients on long-term respiratory support (LTRS) in Austria are lacking. This study aimed to record the pediatric departments active in this field, as well as number and characteristics of patients on LTRS. METHODS: A national cross-sectional study was carried out by means of questionnaires sent to all pediatric departments in Austria. RESULTS: All departments answered to the questionnaires. On June 1st, 2013, the reference day for this study, 12 of the 41 pediatric departments in Austria were active in the field. At this time, these centers were caring for 143 patients, 111 (77.6%) of them under 18 years, which corresponds to a prevalence of 7.4 per 100 000. The patients suffered from neuromuscular disorders (44%), other neurological disorders (18.9%), disorders of respiratory drive (9.1%), obstructive sleep apnea (8.4%), thoracal and spinal diseases (8.4%), pulmonary disorders (4.9%) and other diseases (6.3%). Continuous positive airway pressure was used in 6.3%, non-invasive ventilation in 60.1% and invasive ventilation in 33.6% of the patients, respectively. LTRS was performed at home in 92.3%. CONCLUSION: LTRS represents a common management strategy in children and adolescents with a variety of disorders. Census reports such as this one provide the basis for appropriate planning of resource allocation. The age distribution of our patients shows the need for structured transition into adult care.

Experimental verification of carrier multiplication in graphene.

We report on the first direct experimental observation of carrier multiplication in graphene reaching a multiplication factor of up to 2 and persisting on a picoseconds time scale. Exploiting multicolor pump-probe measurement techniques, the excited nonequilibrium carrier distribution is retrieved on an ultrafast time scale. This provides access to the temporal evolution of the optically excited carrier density and thus allows quantitative conclusions on possible carrier multiplication. Microscopic time- and momentum-resolved calculations on the ultrafast relaxation dynamics of optically excited carriers confirm the observation of carrier multiplication under corresponding experimental conditions, suggesting graphene as a promising material for novel high-efficiency photodetection devices.

The burden of pneumococcal meningitis in Austrian children between 2001 and 2008.

UNLABELLED: The present study was conducted to evaluate the burden of pneumococcal meningitis in Austrian children between 2001 and 2008. Clinical outcome was retrospectively analyzed both on discharge and on follow-up investigations. This study was based on a prospective multicentre surveillance study on hospitalized invasive pneumococcal infections in Austrian children with a total annual "study population" of about 399,000 children aged below 5 years per year. Between 2001 and 2008, 74 cases of pneumococcal meningitis were identified in children aged below 5 years. The mean annual incidence rate for pneumococcal meningitis was 2.3 per 100,000 children in this age group. In 57/74 children (mean age on admission 14.5 ± 13.3 months), outcome data on hospital discharge were available: 5 deaths (8.8%), 20 children (35.1%) with sequelae and 32 children (56.1%) without sequelae were observed. Sequelae on discharge included motor impairment in 8 children (14.0%), hearing impairment in 9 children (15.8%) and/or other complications in 14 children (24.6%). In 7/8 children with motor deficits, matching cerebral lesions were identified by neuroimaging: cerebral infarction in five children, cerebral vasculitis and cerebral abscess in one child each. In 40/57 children, long-term outcome (18.9 ± 20.2 months after discharge) could be assessed: 1 child (2.5%) died 9 months after hospital discharge, 11 children (27.5%) had one or two long-term sequelae and 28 children (70.0%) had no sequelae. Long-term sequelae included motor impairment in three children (7.5%), hearing impairment in nine children (22.5%) and other deficits in two children (5.0%). CONCLUSION: Our study confirms that pneumococcal meningitis causes high mortality and severe long-term sequelae. On long-term follow-up, we observed improvements of motor impairment, but not of hearing impairment.

[IT systems in radiology and IT systems for radiologists]. / IT-Systeme in der Radiologie und IT-Systeme für den Radiologen.

Radiology plays an important role in introduction and use of information technology (IT) systems in the daily clinical routine. The radiology information system (RIS) and picture archiving and communication system (PACS) are the main systems used in a digital radiology department. In this article the basic principles and functions of these systems and trends in development are described.

Current saturation and voltage gain in bilayer graphene field effect transistors.

The emergence of graphene with its unique electrical properties has triggered hopes in the electronic devices community regarding its exploitation as a channel material in field effect transistors. Graphene is especially promising for devices working at frequencies in the 100 GHz range. So far, graphene field effect transistors (GFETs) have shown cutoff frequencies up to 300 GHz, while exhibiting poor voltage gains, another important figure of merit for analog high frequency applications. In the present work, we show that the voltage gain of GFETs can be improved significantly by using bilayer graphene, where a band gap is introduced through a vertical electric displacement field. At a displacement field of -1.7 V/nm the bilayer GFETs exhibit an intrinsic voltage gain up to 35, a factor of 6 higher than the voltage gain in corresponding monolayer GFETs. The transconductance, which limits the cutoff frequency of a transistor, is not degraded by the displacement field and is similar in both monolayer and bilayer GFETs. Using numerical simulations based on an atomistic p(z) tight-binding Hamiltonian we demonstrate that this approach can be extended to sub-100 nm gate lengths.

High on/off ratios in bilayer graphene field effect transistors realized by surface dopants.

The unique property of bilayer graphene to show a band gap tunable by external electrical fields enables a variety of different device concepts with novel functionalities for electronic, optoelectronic, and sensor applications. So far the operation of bilayer graphene-based field effect transistors requires two individual gates to vary the channel's conductance and to create a band gap. In this paper, we report on a method to increase the on/off ratio in single gated bilayer graphene field effect transistors by adsorbate doping. The adsorbate dopants on the upper side of the graphene establish a displacement field perpendicular to the graphene surface breaking the inversion symmetry of the two graphene layers. Low-temperature measurements indicate that the increased on/off ratio is caused by the opening of a mobility gap.

Near-field investigation of THz surface-wave emission from optically excited graphite flakes.

THz emission from an unbiased graphite flake after optical sub-ps pulse inter-band excitation is measured using a novel micro-machined photoconductive probe-tip. Oscillatory behavior of the measured THz near-field emission is shown to originate from electromagnetic eigenmode resonances of the laterally limited graphite flake. The excitation efficiency of the lowest order eigenmode resonances strongly dependents on optical pump location. From this data a radial symmetric charge carrier translocation at the pump location is revealed as the dominating THz surface-wave emission effect. Measurements show good agreement with numerical field simulations of the eigenmode center frequencies and the spectral response expected for THz emission through basal plane oriented radial current surge excitation.

[PIMS-a new pediatric challenge]. / PIMS ­ eine neue pädiatrische Herausforderung: 9-Jahre alter Knabe mit SARS-CoV-2 assoziiertem hyperinflammatorischem Schocksyndrom.

The boy of Egyptian origin was previously healthy. After a history of fever for 7 days, abdominal pain, vomiting and dry cough resistant to treatment with oral antibiotics, he was admitted to hospital. The clinical examination showed a slightly red throat, a tense abdomen and erythema. The blood tests revealed leukocytosis and significantly increased inflammatory parameters. The abdominal ultrasound showed thickened intestinal loops in the left lower abdomen and the echocardiography showed minimal mitral regurgitation, a narrow pericardial effusion lamella over both ventricles and normal coronary arteries. Accordingly, cardiac enzymes were elevated. The day after admission, the boy developed an increasing rash and was transferred to the PICU because of septic shock refractory to high volume resuscitation, requiring hemodynamic support with noradrenaline and noninvasive respiratory assistance. The initial testing for SARS-CoV­2 on nasopharyngeal aspirates was negative twice; however, serum IgG antibodies were positive. Other viral and bacterial infections were excluded as the cause of the symptoms.The patient received IVIG, ASS, furosemide and methylprednisolone and the antibiotic treatment was continued. The dosage of the catecholamine could be reduced according to the patient's condition and the serially performed echocardiographic findings. The patient recovered in his general condition and was discharged from the PICU after 8 days. With the help of a detailed family history, we were able to figure out that the whole family, including the patient himself, had symptoms of a cold about 1 month earlier. Hence, SARS-CoV­2 antibody tests carried out showed a positive result for all of them.Pediatric inflammatory multisystem syndrome (PIMS) can quickly lead to manifest shock symptoms, necessitating close monitoring. A PICU background is crucial to treat possibly occurring symptoms and complications. High-dose steroids are used therapeutically alongside supportive therapies.

Experience with the use of palivizumab together with infection control measures to prevent respiratory syncytial virus outbreaks in neonatal intensive care units.

Respiratory syncytial virus (RSV) frequently causes nosocomial outbreaks in general paediatric wards and occasionally in neonatal intensive care units (NICUs). Conventional infection control measures often fail to prevent the spread of RSV, and it can cause significant morbidity especially in preterm and young infants. We report our experience in preventing an outbreak on a NICU after RSV had been detected in a premature infant. The index case was a 34-day-old premature infant who presented with clinical infection and RSV was detected in a clinical specimen. There were 11 patients in the ward at the time including the index case. The RSV-positive patient was isolated, the ward closed to admissions and infection control measures were implemented. Two patients were transferred to another hospital. Palivizumab 15 mg/kg i.m. was given to all patients and no further cases occurred. All subsequent RSV tests on nasal secretions were negative. Palivizumab combined with conventional infection control measures appeared to prevent the spread of RSV in this NICU. Strategies for the prevention of RSV outbreaks on NICUs all recommend the reinforcement of routine infection control measures. Recommendations concerning the use of palivizumab range from monthly prophylaxis to all infants at risk, to prophylaxis of selected cases only. Currently there are no guidelines for the use of palivizumab in NICUs or for the control of RSV outbreaks.

Randomized comparison of ticlopidine and clopidogrel after intracoronary stent implantation in a broad patient population.

BACKGROUND: Although clopidogrel is used to prevent subacute stent thrombosis, its safety and efficacy have not been compared with ticlopidine in a randomized manner in the United States. METHODS AND RESULTS: Patients with successful intracoronary stent implantation were randomly assigned to therapy with ticlopidine or clopidogrel. Loading doses were administered immediately after the procedure, and the drugs were prescribed for 2 weeks. One thousand sixteen patients were enrolled: 522 patients were randomly assigned to ticlopidine therapy and 494 to clopidogrel. High-risk characteristics included recent myocardial infarction in 41.4% of the cases, angiographically evident thrombus in 20.9%, and abrupt or threatened closure in 3.64%. An intravenous glycoprotein IIb/IIIa inhibitor was used in 48.2% of the cases, and thrombocytopenia occurred in 1.43% of these patients. Failure to complete 2 weeks of therapy occurred in 3.64% of the patients treated with ticlopidine and in 1.62% of the patients treated with clopidogrel (P=0.043). Within 30 days, thrombosis of the stent occurred in 1.92% of the patients in the ticlopidine group and in 2.02% of the clopidogrel group (P=0.901). A major adverse cardiac event occurred in 4.60% of patients receiving ticlopidine and in 3.85% of patients receiving clopidogrel (P=0.551). CONCLUSIONS: Clopidogrel is better tolerated than ticlopidine during a 2-week regimen after intracoronary stent implantation. Combining either thienopyridine with an intravenous platelet IIb/IIIa inhibitor appears to be safe. When applied to a broad spectrum of patients receiving stent implantation, clopidogrel confers similar protection as ticlopidine against subacute stent thrombosis and major adverse cardiac events.

Genetic and developmental analysis of X-inactivation in interspecific hybrid mice suggests a role for the Y chromosome in placental dysplasia.

It has been shown previously that abnormal placental growth, i.e., hyper- and hypoplasia, occurs in crosses and backcrosses between different mouse (Mus) species. A locus that contributes to this abnormal development has been mapped to the X chromosome. Unexpectedly, an influence of fetal sex on placental development has been observed, in that placentas attached to male fetuses tended to exhibit a more pronounced phenotype than placentas attached to females. Here, we have analyzed this sex dependence in more detail. Our results show that differences between male and female placental weights are characteristic of interspecific matings and are not observed in intraspecific Mus musculus matings. The effect is retained in congenic lines that contain differing lengths of M. spretus-derived X chromosome. Expression of the X-linked gene Pgk1 from the maternal allele only and lack of overall activity of two paternally inherited X-linked transgenes indicate that reactivation or lack of inactivation of the paternal X chromosome in trophoblasts of interspecific hybrids is not a frequent occurrence. Thus, the difference between male and female placentas seems not to be caused by faulty preferential X-inactivation. Therefore, these data suggest that the sex difference of placental weights in interspecific hybrids is caused by interactions with the Y chromosome.

Frequency-dependent characterization of THz Sommerfeld wave propagation on single-wires.

In this work, measurements and numerical field simulations highlighting the characteristic propagation behavior of THz surface-wave pulses along bare and dielectrically coated metal wires are presented. An optoelectronic time-domain measurement setup with a freely-positionable probe-tip is used for detection of electrical field transients after different propagation lengths along the wires. Frequency-dependent attenuation and dispersion parameters are determined in the range of 0.02 THz to 0.4 THz. Our results are in good agreement with numerical field simulations considering the propagation of an axial Sommerfeld surface-wave with metallic and dielectric losses. We discuss the influence of wire radius on wave propagation behavior and the application of THz single-wires for sensing.

Embryonic central nervous system angiogenesis does not involve blood-borne endothelial progenitors.

We asked, whether, in the blood of avian embryos, endothelial precursor cells circulate that actually contribute to the growing vascular system in and around the central nervous system (CNS). We compared the morphology and distribution of QH1-positive cells after transplantation of quail paraxial mesoderm, after blood transfusion, in quail-chick parabiosis, or after quail bone-marrow transplantation. After head mesoderm transplantation from quail to chick, we observed sprouting endothelial cells (ECs), capillary tube formation, and chimeric endothelial lining of large arteries in the host brain. These QH1-positive quail cells showed EC morphologies that demonstrated three different aspects of CNS angiogenesis: invasion by means of filopodia, clonal proliferation and tube formation, and integration into preexisting EC layers. After blood transfusion or in chick-quail parabiosis, blood-borne QH1+ cells were found in the lumen of but not integrated into the wall of the host vascular system. Neither were QH1+ cells observed in the capillary walls of parabiotic chick chorioallantoic membranes. In both cases, the quail cells showed typical macrophage morphology. In chicks that had received quail bone marrow transplants onto their chorioallantoic membranes, QH1+ cells with macrophage, but not EC shape were occasionally seen near the inoculation site. We conclude that (1) blood-borne cells do not become ECs or directly contribute to angiogenesis inside, or in vascular plexuses around the CNS during embryonic development; (2) blood-borne cells do not contribute to the intraneural macrophage population of the embryonic CNS.

Expression of fibroblast growth factor-2 and fibroblast growth factor receptor 1 messenger RNAs in spinal ganglia and sciatic nerve: regulation after peripheral nerve lesion.

In order to determine functional roles of basic fibroblast growth factor (FGF-2) in the peripheral nervous system we have analysed the expression of FGF-2 and FGF receptor 1 (FGFR1) in spinal ganglia and the sciatic nerve under normal conditions and after nerve crush using RNAse protection assay and in situ hybridization. In intact spinal ganglia, both FGF-2 and FGFR1 messenger RNAs are expressed, albeit at different levels. In situ hybridization identifies satellite cells as the source of FGF-2 and sensory neurons as the source of FGFR1 suggesting a paracrine mode of action of FGF-2 on sensory neurons. One day after crush lesion FGF-2 is significantly up-regulated in sensory ganglia L4-L6. Highest levels are found at day 7; control levels are approached after 28 days. FGFR1 messenger RNA, which is strongly expressed in intact spinal ganglia, displays no significant change after lesion. In the intact sciatic nerve, FGFR1 messenger RNA is detected at higher levels than FGF-2 messenger RNA. After injury, both transcripts display a time-dependent up-regulation in both the proximal and distal nerve stump. Schwann cells, as a putative source of the sciatic nerve-derived FGF-2, express both FGF-2 and FGFR1 messenger RNAs in vitro. The FGFR1 transcript level is increased in the presence of forskolin. FGF-2 does not affect expression of FGFR1 messenger RNA but stimulates its own expression. These results show that during peripheral nerve regeneration FGF-2 is up-regulated in both the crushed nerve and the respective spinal ganglia suggesting a possible physiological function of FGF-2 during the regeneration process.

2 Years' experience with inspiratory muscle training in patients with neuromuscular disorders.

PURPOSE: The aim of our study was to assess the long-term effects of specific inspiratory muscle training (IMT) in patients with neuromuscular disorders (NMDs) who have various degrees of respiratory impairment. PATIENTS AND METHODS: Twenty-seven patients with NMDs (Duchenne's muscular dystrophy, 18 patients; spinal muscular atrophy, 9 patients) underwent 24 months of IMT. Patients were divided into three groups according to their vital capacity (VC) values. VC was measured as the parameter for the respiratory system involvement of the disease. Maximal inspiratory pressure (PImax) was assessed as the parameter for respiratory muscle strength, and the results of the 12-s maximum voluntary ventilation test (12sMVV) were assessed as the parameter for respiratory muscle endurance. Pulmonary and inspiratory muscle function parameters were assessed 6 months before training, at the beginning of training, and then every 3 months. RESULTS: The PImax values improved in group A (VC, 27 to 50% predicted) from 51.45 to 87.00 cm H(2)O, in group B (VC, 51 to 70% predicted) from 59.38 to 94.4 cm H(2)O, and in group C (VC, 71 to 96% predicted) from 71.25 to 99.00 cm H(2)O. The 12sMVV values improved in group A from 52.69 to 69.50 L/min, in group B from 53.18 to 62.40 L/min, and in group C from 59.48 to 70.5 L/min. For all three groups, there was a significant improvement of PImax (p < 0.007) and 12sMVV (p < 0.015) until the 10th month when a plateau phase was reached with no decline in the following month until the end of training. CONCLUSION: With IMT, respiratory muscle function can be improved in the long term of up to 2 years.

Impulsive excitation of phonon-pair combination states by second-order raman scattering

The excitation of (100)-oriented KTaO3 with 25-fs laser pulses impulsively drives phonon-pair combination states via second-order Raman scattering. Oscillations in the phonon-amplitude covariance at the sum and difference frequency of the two involved phonons are observed in a spectrally and temporally resolved pump-probe experiment. Transmission changes of the sample are dominated by contributions of wave vector conserving phonon-pair combinations from the entire Brillouin zone that have maxima in their combined density of states. For low temperatures the temperature dependence of the covariance oscillations of different phonon combinations is reproduced by a quantum-mechanical model.

Coupled bloch-phonon oscillations in semiconductor superlattices

We investigate coherent Bloch oscillations in GaAs/AlxGa1-xAs superlattices with electronic miniband widths larger than the optical phonon energy. In these superlattices the Bloch frequency can be tuned into resonance with the optical phonon. Close to resonance a direct coupling of Bloch oscillations to LO phonons is observed which gives rise to the coherent excitation of LO phonons. The density necessary for driving coherent LO phonons via Bloch oscillations is about 2 orders of magnitude smaller than the density necessary to drive coherent LO phonons in bulk GaAs. The experimental observations are confirmed by the theoretical description of this phenomenon [A.W. Ghosh et al., Phys. Rev. Lett. 85, 1084 (2000)].

A randomized comparison of intravenous amrinone versus dobutamine in older patients with decompensated congestive heart failure.

OBJECTIVE: To compare the hemodynamic effects of amrinone and dobutamine in patients 75 years of age or older who have severe congestive heart failure requiring invasive hemodynamic monitoring and inotropic support. DESIGN: Prospective, randomized, double-blind clinical trial. SETTING: Coronary care unit of a university teaching hospital. PARTICIPANTS: Fourteen patients > or = 75 years of age (mean 80.3 +/- 5.7 years) with refractory New York Heart Association class IV congestive heart failure. All patients had a cardiac index < 2.5 L/min/M2 (mean 1.8 +/- 0.3 L/min/M2), pulmonary capillary wedge pressure > or = 18 mm Hg (mean 26 +/- 10 mm Hg), and left ventricular ejection fraction < 40% (mean 26 +/- 10%). INTERVENTION: Patients were randomly assigned to treatment with 2-hour infusions of amrinone (n = 7) or dobutamine (n = 7) at fixed dosages of 5 and 10 micrograms/kg/min. MEASUREMENTS: Complete hemodynamic data were obtained at baseline and after each 2-hour medication infusion. Transthoracic two-dimensional echocardiography was performed at baseline and after the 10 micrograms/kg/min medication dose. The primary analysis compared the effects of the two drugs on cardiac index and stroke volume index at each of the two dosages. RESULTS: Both amrinone and dobutamine had salutary hemodynamic effects, as indicated by improvements in cardiac index, stroke volume index, pulmonary capillary wedge pressure, and systemic vascular resistance (all P < .05 except effect of amrinone on stroke index and wedge pressure). Although the overall hemodynamic effects of amrinone and dobutamine were similar, stroke volume index was higher with dobutamine at the 10 micrograms/kg/min dose (35 +/- 7 ml/M2 vs 26 +/- 6 mL/M2; P = .045). Two dobutamine patients were withdrawn from the study after the 5 micrograms/kg/min dose due to adverse effects (tachycardia, increased ventricular ectopy). One additional patient in each group was noted to have ventricular arrhythmias not requiring termination of the protocol. CONCLUSIONS: Both amrinone and dobutamine are efficacious in improving hemodynamics in older patients with severe congestive heart failure caused by left ventricular contractile dysfunction. Despite the effect of aging on beta-adrenergic responsiveness, dobutamine is at least as effective as amrinone but may be associated with a higher incidence of arrhythmic side effects.

Resolution of obstructive sleep apnea syndrome after adenoidectomy in congenital central hypoventilation syndrome.

We report on a 2 1/2-year-old boy who is currently ventilated at home by positive pressure ventilation through a nasal mask during the night because of congenital central hypoventilation syndrome (CCHS). Up to age 2 he had developed normally. A reevaluation was performed because of symptoms suggestive of obstructive sleep apnea syndrome (OSAS), including snoring, nocturnal sweating, frequent nighttime awakenings, speech impairment, daytime fatigue, and failure to thrive. A sleep study indicated obstructive apnea episodes lasting up to 40 s and arterial desaturations below 50% during spontaneous sleep. During mechanical ventilation snoring persisted, and capillary PCO2 rose to 60 mm Hg. Partial upper airway obstruction, leaking around the mask, and arousal movements developed on passive flexion of the neck to 20 degrees. After adenoidectomy, symptoms of OSAS resolved. There were no more obstructive apneas during spontaneous sleep, but obstructive apneas could be provoked by neck flexion to 20 degrees. During ventilation, neck flexion of 20 degrees was tolerated, but a 40 degrees flexion led to partial obstruction. In CCHS patients, the problem of upper airway obstruction is rarely noted because most patients are ventilated through a permanent tracheostomy. Today, noninvasive ventilation strategies are becoming more common. Reduced activity of upper airway muscles and impaired reflex mechanisms could lead to upper airway obstruction during face mask positive pressure ventilation in children with CCHS. Enlarged adenoids worsened this problem in our patient, leading to insufficient ventilation and OSAS. Adenoidectomy resolved symptoms of OSAS and enabled successful nasal mask ventilation. Close follow-up of the patient avoided hypoxia and sequelae from OSAS such as pulmonary hypertension.