Quantitative analysis of mechanical and electrostatic properties of poly(lactic) acid fibers and poly(lactic) acid-carbon nanotube composites using atomic force microscopy.

We use atomic force microscopy (AFM) to perform a systematic quantitative characterization of the elastic modulus and dielectric constant of poly(L-lactic acid) electrospun nanofibers (PLLA), as well as composites of PLLA fibers with 1.0 wt% embedded multiwall carbon nanotubes (MWCNTs-PLLA). The elastic moduli are measured in the fiber skin region via AFM nanoindentation, and the dielectric constants are determined by measuring the phase shifts obtained via electrostatic force microscopy (EFM). We find that the average value for the elastic modulus for PLLA fibers is (9.8 ± 0.9) GPa, which is a factor of 2 larger than the measured average elastic modulus for MWCNT-PLLA composites (4.1 ± 0.7) GPa. We also use EFM to measure dielectric constants for both types of fibers. These measurements show that the dielectric constants of the MWCNT-PLLA fibers are significantly larger than the corresponding values obtained for PLLA fiber. This result is consistent with the higher polarizability of the MWCNT-PLLA composites. The measurement methods presented are general, and can be applied to determine the mechanical and electrical properties of other polymers and polymer nanocomposites.

Critical slowing down in circuit quantum electrodynamics.

Critical slowing down of the time it takes a system to reach equilibrium is a key signature of bistability in dissipative first-order phase transitions. Understanding and characterizing this process can shed light on the underlying many-body dynamics that occur close to such a transition. Here, we explore the rich quantum activation dynamics and the appearance of critical slowing down in an engineered superconducting quantum circuit. Specifically, we investigate the intermediate bistable regime of the generalized Jaynes-Cummings Hamiltonian (GJC), realized by a circuit quantum electrodynamics (cQED) system consisting of a transmon qubit coupled to a microwave cavity. We find a previously unidentified regime of quantum activation in which the critical slowing down reaches saturation and, by comparing our experimental results with a range of models, we shed light on the fundamental role played by the qubit in this regime.

Elevated oxygen fraction reduces cilial abundance in explanted human bronchial tissue.

The effect of hyperoxia on ciliary abundance in cultured explants of adult human bronchus was investigated. Bronchus samples were removed during surgery from patients receiving pneumonectomy or lobectomy for malignancy. Part or all of each of these samples was used for measurement of cilial abundance by scanning electron microscopy (SEM); in many cases the remainder was subdivided and cultured at 37 degrees C in DMEM medium, maintaining an air interface at the ciliated surface of each segment. Cultured segments were exposed to normoxia or hyperoxia (95% O(2)), and a segment was removed every other day for quantification of cilial abundance by SEM. There was a significant inverse relationship between smoking history and abundance (p = .017; ANOVA); mean values for nonsmokers, ex-smokers, and smokers were 98.2% (n = 6), 97.0% (n = 17), and 84.02% (n = 9), respectively. There was some loss of cilia on explant segments cultured under normoxia, but the rate of loss from segments cultured under hyperoxia was significantly greater (W test, p = .00011); rate constants (means +/- SE) for cilial loss of 0.0208 +/- 0.0044 day(-1) and 0.0880 +/- 0.0179 day(-1) were found for explant segments exposed to 21 and 95% O2, respectively (n = 20).

Circuit quantum acoustodynamics with surface acoustic waves.

The experimental investigation of quantum devices incorporating mechanical resonators has opened up new frontiers in the study of quantum mechanics at a macroscopic level. It has recently been shown that surface acoustic waves (SAWs) can be piezoelectrically coupled to superconducting qubits, and confined in high-quality Fabry-Perot cavities in the quantum regime. Here we present measurements of a device in which a superconducting qubit is coupled to a SAW cavity, realising a surface acoustic version of cavity quantum electrodynamics. We use measurements of the AC Stark shift between the two systems to determine the coupling strength, which is in agreement with a theoretical model. This quantum acoustodynamics architecture may be used to develop new quantum acoustic devices in which quantum information is stored in trapped on-chip acoustic wavepackets, and manipulated in ways that are impossible with purely electromagnetic signals, due to the 105 times slower mechanical waves.In this work, Manenti et al. present measurements of a device in which a tuneable transmon qubit is piezoelectrically coupled to a surface acoustic wave cavity, realising circuit quantum acoustodynamic architecture. This may be used to develop new quantum acoustic devices.

Fibrin sealant treatment of splenic injuries during oesophagectomy.

The incidence of 'accidental' splenectomy during oesophagectomy varies from 4 to 42% and leads to an increase in sepsis, anastomotic leakage and mortality. Therefore, preservation of the spleen should be the aim of treatment whenever splenic injury occurs. We describe the use of fibrin glue delivered as a thin film by a spray applicator for rapid and definitive haemostasis of grades 1 and 2 splenic injuries in patients undergoing oesophagectomy.

Dissecting intramural haematoma of the oesophagus.

Dissecting intramural haematoma of the oesophagus (DIHO) is a rare condition, which has an excellent prognosis when managed conservatively. Awareness of this condition is vital to guide subsequent investigations and avoid inappropriate treatment or unnecessary surgical intervention. We describe an unusual case of massive DIHO causing left atrial compression presenting with pericarditic electrocardiographic changes and document the utility of endoscopic ultrasound/computed tomography to make the diagnosis.

High-Dose Intravenous Octreotide Is Safe and May Be Superior to Surgery in Managing Severe Postesophagectomy Chylothorax in High-Risk Patients.

Postesophagectomy chylothorax is a relatively rare but potentially lethal complication. Management can be challenging, especially of patients after radiotherapy. Chest tube drainage, bowel rest, total parenteral nutrition, and adequate fluid replacement are the preferred first-line treatment. Thoracic duct band ligation is the approach of last resort; however, surgical reexploration is often not an option in these patients. The use of octreotide to control chylothorax in adults has been reported, but mainly when given in low subcutaneous doses. We report the successful use of high intravenous doses of octreotide to manage large postesophagectomy chylothorax in an adult after failed band ligation.

Oesphageal stenting for palliation of malignant mesothelioma.

Dyspahgia in patients with malignant mesothelioma is usually due to direct infiltration of the eosophagus by the tumour. It can be distressing for the patient and challenging for the physician to treat. We describe three cases in which this condition has been successfully palliated with self expanding esophageal stents.