Wafer-scale detachable monocrystalline germanium nanomembranes for the growth of III-V materials and substrate reuse.

Germanium (Ge) is increasingly used as a substrate for high-performance optoelectronics, photovoltaics, and electronic devices. These devices are usually grown on thick and rigid Ge substrates manufactured by classical wafering techniques. Nanomembranes (NMs) provide an alternative to this approach while offering wafer-scale lateral dimensions, weight reduction, waste limitation, and cost effectiveness. Herein, we introduce the Porous germanium Efficient Epitaxial LayEr Release (PEELER) process, which consists of the fabrication of wafer-scale detachable Ge NMs on porous Ge (PGe) and substrate reuse. We demonstrate the growth of Ge NMs with monocrystalline quality as revealed by high-resolution transmission electron microscopy (HRTEM) characterization. Together with the surface roughness below 1 nm, it makes the Ge NMs suitable for growth of III-V materials. Additionally, the embedded nanoengineered weak layer enables the detachment of the Ge NMs. Finally, we demonstrate the wet-etch-reconditioning process of the Ge substrate, allowing its reuse, to produce multiple free-standing NMs from a single parent wafer. The PEELER process significantly reduces the consumption of Ge in the fabrication process, paving the way for a new generation of low-cost flexible optoelectronic devices.

Critically ill infants with SARS-COV-2 delta variant infection.

BACKGROUND: SARS-CoV-2 is described to cause mild to moderate symptoms in children. To date, clinical data and symptoms of the Delta variant in pediatric patients are lacking. AIM: To describe clinical characteristics and outcomes of infants admitted in the pediatric intensive care unit (PICU) during the period of Delta variant predominance. METHODS: We performed a retrospective study, between June 23, 2021 and August 16, 2021. We included children aged under 15 years, admitted to PICU with severe and critical form of SARS-CoV-2 infection as confirmed by RT-PCR. We reviewed medical records for all patients. RESULTS: During the study period, 20 infants were included. The median age was 47 days (IQR: 26.5-77). The sex ratio was 0.8 (9 males). No underlying medical conditions were noted. Parents were not vaccinated. Respiratory involvement was the main feature to be observed in our cohort. Eleven patients had pediatric acute respiratory distress (PARDS) with a median oxygen saturation index (OSI) of 9 (IQR: 7-11). PARDS was mild in 4 cases, moderate in 5 cases and severe in 2 cases. Hemodynamic instability was observed in 4 cases. The main radiological finding was ground glass opacities in 11 cases. Seventeen patients were mechanically ventilated and 3 of them were escalated to high-frequency oscillatory ventilation. The median duration of mechanical ventilation was 6 days (IQR 2.5-12.5). The remaining patients were managed with high flow nasal cannula. Four patients died. CONCLUSION: We report herein a case series of very young infants, with no comorbidities, and with a life-threatening illness due to SARS-CoV-2 Delta variant.

Severe and critical SARS-COV-2 delta variant infection in infants without underlying medical conditions.

We report herein a case series of infants, with no comorbidities, who developed a life-threatening illness due to the SARS-CoV-2 Delta variant. We retrospectively reviewed the medical records of children, aged under 15 years, admitted to PICU, during the peak of Delta infection, between June 23 and August 16 2021, with severe and critical forms of SARS-CoV-2 infection, confirmed by RT-PCR. Twenty infants were included, the median age was 47 days (IQR: 26.5-77) and sex ratio was 0.8. No underlying medical conditions were noted. Parents were not vaccinated. Respiratory involvement was the main feature observed. Eleven patients had paediatric acute respiratory distress (PARDS) with a median oxygen saturation index (OSI) of 9 (IQR: 7-11). PARDS was mild in four, moderate in five, and severe in two cases. Hemodynamic instability was observed in 4 cases. The main radiological finding was ground glass opacities in 11 cases. Seventeen patients were mechanically ventilated, and three of them were escalated to high-frequency oscillatory ventilation. The median duration of mechanical ventilation was 6 days (IQR 2.5-12.5). The remaining patients were managed with high-flow nasal cannula. Four patients died.

High flow nasal cannula therapy versus continuous positive airway pressure and nasal positive pressure ventilation in infants with severe bronchiolitis: a randomized controlled trial.

INTRODUCTION: non-invasive ventilation is widely used in the respiratory management of severe bronchiolitis. METHODS: a randomized controlled trial was carried out in a tertiary pediatric university hospital´s PICU over 3 years to compare between continuous positive airway pressure/nasal positive pressure ventilation (CPAP/NPPV) and high flow nasal cannula (HFNC) devices for severe bronchiolitis. The trial was recorded in the national library of medicine registry (NCT04650230). Patients aged from 7 days to 6 months, admitted for severe bronchiolitis were enrolled. Eligible patients were randomly chosen to receive either HFNC or CPAP/NPPV. If HFNC failed, the switch to CPAP/NPPV was allowed. Mechanical ventilation was the last resort in case of CPAP/NPPV device failure. The primary outcome was the success of the treatment defined by no need of care escalation. The secondary outcomes were failure predictors, intubation rate, stay length, serious adverse events, and mortality. RESULTS: a total of 268 patients were enrolled. The data of 255 participants were analyzed. The mean age was 51.13 ± 34.43 days. Participants were randomized into two groups; HFNC group (n=130) and CPAP/NPPV group (n=125). The success of the treatment was significantly higher in the CPAP/NPPV group (70.4% [61.6%- 78.2%) comparing to HFNC group (50.7% [41.9%- 59.6%])- (p=0.001). For secondary outcomes, lower baseline pH was the only significant failure predictor in the CPAP/NPPV group (p=0.035). There were no differences in intubation rate or serious adverse events between the groups. CONCLUSION: high flow nasal cannula was safe and efficient, but CPAP/ NPPV was better in preventing treatment failure. The switch to CPAP/NPPV if HFNC failed, avoided intubation in 54% of the cases.

First Tunisian Cluster Admissions of Critically Ill Patients with Multisystem Inflammatory Syndrome in Children (MIS-C).

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a new emerging severe disease that is temporally related to previous exposure to coronavirus infection disease (COVID-19). AIM: To describe the clinical features, laboratory findings, therapies, and outcomes for the first Tunisian cluster admissions of critically ill children with severe MIS-C. METHODS: Retrospective study conducted from November 01 to November 30, 2020According to the WHO definition case, we included eight children aged less than 15 years who were admitted to our pediatric intensive care and met MIS-C criteria. We reviewed all patients' medical records to collect demographic and clinical data, severity scores, laboratory test results, echocardiographic findings, treatment, and outcomes. RESULTS: The median age was 8 years (IQR: 4-10years). All children were previously fit and well. Seven patients were boys. Known exposure to COVID-19 was reported in 4 cases. Fever and gastrointestinal symptoms were reported in all cases. Five patients had marked abdominal pain and were examined by the surgeon for possible appendicitis. Seven patients had diarrhea. On examination, we found rash (n=7), conjunctivitis (n=7), cheilitis (n=5), and meningism (n=3). We reported cardiac dysfunction in 7 cases and shock with hypotension in 3 cases. All patients received immunoglobulins, methylprednisolone, and a low dose of aspirin. No deaths occurred. CONCLUSION: We reported here the first Tunisian cluster admissions of 8 critically ill children with MIS-C to highlight the increase of a new severe emerging disease with evidence of prior COVID-19 infection in older children.