Compact SAW aerosol generator

In this work, we discuss and demonstrate the principle features of surface acoustic wave (SAW) aerosol generation, based on the properties of the fluid supply, the acoustic wave field and the acoustowetting phenomena. Furthermore, we demonstrate a compact SAW-based aerosol generator amenable to mass production fabricated using simple techniques including photolithography, computerized numerical control (CNC) milling and printed circuit board (PCB) manufacturing. Using this device, we present comprehensive experimental results exploring the complexity of the acoustic atomization process and the influence of fluid supply position and geometry, SAW power and fluid flow rate on the device functionality. These factors in turn influence the droplet size distribution, measured here, that is important for applications including liquid chromatography, pulmonary therapies, thin film deposition and olfactory displays

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications

BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (VT) size was 500 ml, or 7 to 9 ml kg1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P < 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P < 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high VT and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome

Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications: LAS VEGAS - An observational study in 29 countries

BACKGROUND Limited information exists about the epidemiology and outcome of surgical patients at increased risk of postoperative pulmonary complications (PPCs), and how intraoperative ventilation was managed in these patients. OBJECTIVES To determine the incidence of surgical patients at increased risk of PPCs, and to compare the intraoperative ventilation management and postoperative outcomes with patients at low risk of PPCs. DESIGN This was a prospective international 1-week observational study using the ‘Assess Respiratory Risk in Surgical Patients in Catalonia risk score’ (ARISCAT score) for PPC for risk stratification. PATIENTS AND SETTING Adult patients requiring intraoperative ventilation during general anaesthesia for surgery in 146 hospitals across 29 countries. MAIN OUTCOME MEASURES The primary outcome was the incidence of patients at increased risk of PPCs based on the ARISCAT score. Secondary outcomes included intraoperative ventilatory management and clinical outcomes. RESULTS A total of 9864 patients fulfilled the inclusion criteria. The incidence of patients at increased risk was 28.4%. The most frequently chosen tidal volume (V T) size was 500 ml, or 7 to 9 ml kg−1 predicted body weight, slightly lower in patients at increased risk of PPCs. Levels of positive end-expiratory pressure (PEEP) were slightly higher in patients at increased risk of PPCs, with 14.3% receiving more than 5 cmH2O PEEP compared with 7.6% in patients at low risk of PPCs (P ˂ 0.001). Patients with a predicted preoperative increased risk of PPCs developed PPCs more frequently: 19 versus 7%, relative risk (RR) 3.16 (95% confidence interval 2.76 to 3.61), P ˂ 0.001) and had longer hospital stays. The only ventilatory factor associated with the occurrence of PPCs was the peak pressure. CONCLUSION The incidence of patients with a predicted increased risk of PPCs is high. A large proportion of patients receive high V T and low PEEP levels. PPCs occur frequently in patients at increased risk, with worse clinical outcome.</p

Mesozoic deposits of SW Gondwana (Namibia): unravelling Gondwanan sedimentary dispersion drivers by detrital zircon

The Namibian Mesozoic successions may be remnant of a high dynamic sedimentary system that is characterized by multiple stages of sediment accumulation and erosion with contemporaneous homogenization starting with the deposition of the Permo-Carboniferous Dwyka Group strata and continues at least until the Lower Cretaceous. The Lower Cretaceous sedimentary system is interpreted to have involved at least an area covering the whole SW Gondwana, documenting the sedimentary history during the evolution from an ice house environment to an arid desert. To test the sediment homogenization hypothesis, we applied a combination of isotopic and morphometric data on detrital zircon grains, as well as whole-rock geochemical data of selected Mesozoic sandstones from Namibia. As a base for the interpretation of the detrital zircon age data we compiled a zircon age dataset with c. 44,000 analyses for the southern African region. All samples reveal a major detrital pan-African zircon age peak of c. 0.5–0.7 Ga sourced from the pan-African magmatic events occurring around the Kalahari Craton margin. The lowermost Triassic is characterized by the occurrence of additional Mesoproterozoic and Paleoproterozoic age peaks of c. 1.0–1.2 Ga and 1.8–2.0 Ga with a majority of zircon grains showing angular shapes. The protosource of these grains is interpreted to possibly be the Namaqua Metamorphic Complex and other Paleoproterozoic structural units deformed in course of the Namaqua orogeny. In contrast, other samples show a prominent Permo-Triassic age peak and completely rounded zircon grains, putatively derived from within the Gondwanides volcanic arc. The disparity in the zircon age pattern may point towards a change in provenance and also a change in the whole system of zircon recycling during the Mesozoic southern Gondwana. The Lower Triassic Neu Loore fm. are constrained to more local bedrock sources and short zircon transport distance. In contrast, zircon grains of the Middle Triassic Omingonde, the Jurassic Etjo und the Cretaceous Twyfelfontein formations are an expression for a major recycling and sediment homogenization system. The system was facilitated by an interplay between fluvial and eolian sedimentary transport systems

Integrated sensitive on-chip ion field effect transistors based on wrinkled ingaas nanomembranes

Self-organized wrinkling of pre-strained nanomembranes into nanochannels is used to fabricate a fully integrated nanofluidic device for the development of ion field effect transistors (IFETs). Constrained by the structure and shape of the membrane, the deterministic wrinkling process leads to a versatile variation of channel types such as straight two-way channels, three-way branched channels, or even four-way intersection channels. The fabrication of straight channels is well controllable and offers the opportunity to integrate multiple IFET devices into a single chip. Thus, several IFETs are fabricated on a single chip using a III-V semiconductor substrate to control the ion separation and to measure the ion current of a diluted potassium chloride electrolyte solution