Controllable Tunneling of Single Flux Quanta Mediated by Quantum Phase Slip in Disordered Superconducting Loops

Quantum phase slip (QPS) is the exact dual to the well-known Josephson effect. Although there are numerous proposals for applications of QPS devices, experimental work to develop these remains in the relatively early stages. Significant barriers to exploiting QPS nanowires for useful technologies still exist, such as establishing robust nanowire-fabrication methods that allow coupling to low-loss circuits, and demonstrating control over the QPS process with an experimenter-controlled external bias. Here we report experiments that show that both of these barriers have been overcome. We present measurements at 300 mK of Nb N coplanar-waveguide (CPW) resonators embedded with nanowires fabricated using a neon focused ion beam. The internal quality factor exceeds 2 × 10 4 —significantly higher than previously reported in comparable experiments. The resonator frequency tunes periodically with an applied magnetic field, revealing tunneling of the order parameter that always occurs at half-integer values of the applied flux. In contrast to previous studies of single QPS, the order-parameter tunneling is shown to be adiabatic, demonstrating improved control over energy dissipation in nanowire QPS circuits. Our results highlight a promising pathway towards realizing low-loss nanowire-based QPS devices

A practical comparison of firm valuation models: cash flow, dividend and income

Our research, based on a sample of listed Australian firms, indicates that the residual income model provides better estimates of firm value than two other commonly used models. It also provides advantages in that there is less need to forecast returns as far into the future and, with this model, a terminal value based upon a constant future return (or relatively low growth rates) can be used. This obviates the need to estimate an expected long-term growth rate, which is always problematic

Nonlinear Quantum Processes in Superconducting Resonators Terminated by Neon-Focused-Ion-Beam-Fabricated Superconducting Nanowires

We have used a neon focused-ion-beam to fabricate both nanoscale Nb Dayem bridges and NbN phase-slip nanowires located at the short-circuited end of quarter-wavelength coplanar waveguide resonators. The Dayem bridge devices show flux-tunability and intrinsic quality factor exceeding 10 000 at 300 mK up to local fields of at least 60 mT. The NbN nanowires show signatures of incoherent quantum tunneling of flux at 300 mK

Vacuum ultraviolet photochemical selectivearea atomic layer deposition of Al2O3 dielectrics

We report the photochemical atomic layer deposition of Al2O3 thin films and the use of this process to achieve area-selective film deposition. A shuttered vacuum ultraviolet (VUV) light source is used to excite molecular oxygen and trimethyl aluminum to deposit films at 60 degrees C. In-situ QCM and post-deposition ellipsometric measurements both show that the deposition rate is saturative as a function of irradiation time. Selective area deposition was achieved by projecting the VUV light through a metalized magnesium fluoride photolithographic mask and the selectivity of deposition on the illuminated and masked regions of the substrate is a logarithmic function of the UV exposure time. The Al2O3 films exhibit dielectric constants of 8 - 10 at 1 MHz after forming gas annealing, similar to films deposited by conventional thermal ALD. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License

Atrial fibrillation in embolic stroke of undetermined source: role of advanced imaging of left atrial function

\ua9 The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology. AIMS: Atrial fibrillation (AF) is detected in over 30% of patients following an embolic stroke of undetermined source (ESUS) when monitored with an implantable loop recorder (ILR). Identifying AF in ESUS survivors has significant therapeutic implications, and AF risk is essential to guide screening with long-term monitoring. The present study aimed to establish the role of left atrial (LA) function in subsequent AF identification and develop a risk model for AF in ESUS. METHODS AND RESULTS: We conducted a single-centre retrospective case-control study including all patients with ESUS referred to our institution for ILR implantation from December 2009 to September 2019. We recorded clinical variables at baseline and analysed transthoracic echocardiograms in sinus rhythm. Univariate and multivariable analyses were performed to inform variables associated with AF. Lasso regression analysis was used to develop a risk prediction model for AF. The risk model was internally validated using bootstrapping. Three hundred and twenty-three patients with ESUS underwent ILR implantation. In the ESUS population, 293 had a stroke, whereas 30 had suffered a transient ischaemic attack as adjudicated by a senior stroke physician. Atrial fibrillation of any duration was detected in 47.1%. The mean follow-up was 710 days. Following lasso regression with backwards elimination, we combined increasing lateral PA (the time interval from the beginning of the P wave on the surface electrocardiogram to the beginning of the A\u27 wave on pulsed wave tissue Doppler of the lateral mitral annulus) [odds ratio (OR) 1.011], increasing Age (OR 1.035), higher Diastolic blood pressure (OR 1.027), and abnormal LA reservoir Strain (OR 0.973) into a new PADS score. The probability of identifying AF can be estimated using the formula. Model discrimination was good [area under the curve (AUC) 0.72]. The PADS score was internally validated using bootstrapping with 1000 samples of 150 patients showing consistent results with an AUC of 0.73. CONCLUSION: The novel PADS score can identify the risk of AF on prolonged monitoring with ILR following ESUS and should be considered a dedicated risk stratification tool for decision-making regarding the screening strategy for AF in stroke.One-third of patients with a type of stroke called embolic stroke of undetermined source (ESUS) also have a heart condition called atrial fibrillation (AF), which increases their risk of having another stroke. However, we do not know why some patients with ESUS develop AF. To figure this out, we studied 323 patients with ESUS and used a special device to monitor their heart rhythm continuously for up to 3 years, an implantable loop recorder. We also looked at their medical history, performed a heart ultrasound, and identified some factors that increase the risk of identifying AF in the future. Factors associated with future AF include older age, higher diastolic blood pressure, and problems with the co-ordination and function of the upper left chamber of the heart called the left atrium.Based on these factors, we created a new scoring system that can identify patients who are at higher risk of developing AF better than the current scoring systems, the PADS score. This can potentially help doctors provide more targeted and effective treatment to these patients, ultimately aiming to reduce their risk of having another stroke

Whole home exercise intervention for depression in older care home residents (the OPERA study) : a process evaluation

Background: The ‘Older People’s Exercise intervention in Residential and nursing Accommodation’ (OPERA) cluster randomised trial evaluated the impact of training for care home staff together with twice-weekly, physiotherapist-led exercise classes on depressive symptoms in care home residents, but found no effect. We report a process evaluation exploring potential explanations for the lack of effect. Methods: The OPERA trial included over 1,000 residents in 78 care homes in the UK. We used a mixed methods approach including quantitative data collected from all homes. In eight case study homes, we carried out repeated periods of observation and interviews with residents, care staff and managers. At the end of the intervention, we held focus groups with OPERA research staff. We reported our first findings before the trial outcome was known. Results: Homes showed large variations in activity at baseline and throughout the trial. Overall attendance rate at the group exercise sessions was low (50%). We considered two issues that might explain the negative outcome: whether the intervention changed the culture of the homes, and whether the residents engaged with the intervention. We found low levels of staff training, few home champions for the intervention and a culture that prioritised protecting residents from harm over encouraging activity. The trial team delivered 3,191 exercise groups but only 36% of participants attended at least 1 group per week and depressed residents attended significantly fewer groups than those who were not depressed. Residents were very frail and therefore most groups only included seated exercises. Conclusions: The intervention did not change the culture of the homes and, in the case study homes, activity levels did not change outside the exercise groups. Residents did not engage in the exercise groups at a sufficient level, and this was particularly true for those with depressive symptoms at baseline. The physical and mental frailty of care home residents may make it impossible to deliver a sufficiently intense exercise intervention to impact on depressive symptoms

Clinical ethics revisited

A decade ago, we reviewed the field of clinical ethics; assessed its progress in research, education, and ethics committees and consultation; and made predictions about the future of the field. In this article, we revisit clinical ethics to examine our earlier observations, highlight key developments, and discuss remaining challenges for clinical ethics, including the need to develop a global perspective on clinical ethics problems

Comparison of atomic layer deposited Al2O3 and (Ta2O5)0.12(Al2O3)0.88 gate dielectrics on the characteristics of GaN-capped AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors

The current research investigates the potential advantages of replacing Al2O3 with (Ta2O5)0.12(Al2O3)0.88 as a higher dielectric constant (κ) gate dielectric for GaN-based metal-oxide-semiconductor high electron mobility transistors (MOS-HEMTs). The electrical characteristics of GaN-capped AlGaN/GaN MOS-HEMT devices with (Ta2O5)0.12(Al2O3)0.88 as the gate dielectric are compared to devices with Al2O3 gate dielectric and devices without any gate dielectric (Schottky HEMTs). Compared to the Al2O3 MOS-HEMT, the (Ta2O5)0.12(Al2O3)0.88 MOS-HEMT achieves a larger capacitance and a smaller absolute threshold voltage, together with a higher two-dimensional electron gas carrier concentration. This results in a superior improvement of the output characteristics with respect to the Schottky HEMT, with higher maximum and saturation drain current values observed from DC current-voltage measurements. Gate transfer measurements also show a higher transconductance for the (Ta2O5)0.12(Al2O3)0.88 MOS-HEMT. Furthermore, from OFF-state measurements, the (Ta2O5)0.12(Al2O3)0.88 MOS-HEMT shows a larger reduction of the gate leakage current in comparison to the Al2O3 MOS-HEMT. These results demonstrate that the increase in κ of (Ta2O5)0.12(Al2O3)0.88 compared with Al2O3 leads to enhanced device performance when the ternary phase is used as a gate dielectric in the GaN-based MOS-HEMT

2-Methoxyoestradiol-3,17-O,O-bis-sulphamate and 2-deoxy-D-glucose in combination: a potential treatment for breast and prostate cancer

Drug combination therapy is a key strategy to improve treatment efficacy and survival of cancer patients. In this study the effects of combining 2-methoxyoestradiol-3,17-O,O-bis-sulphamate (STX140), a microtubule disruptor, with 2-deoxy-D-glucose (2DG) were assessed in MCF-7 (breast) and LNCaP (prostate) xenograft models in vivo. In mice bearing MCF-7 xenografts, daily p.o. administration of STX140 (5 mg kg−1) resulted in a 46% (P<0.05) reduction of tumour volume. However, the combination of STX140 (5 mg kg−1 p.o.) and 2DG (2 g kg−1 i.p.) reduced tumour volume by 76% (P<0.001). 2-Methoxyoestradiol-3,17-O,O-bis-sulphamate also reduced tumour vessel density. 2-Deoxy-D-glucose alone had no significant effect on tumour volume or vessel density. A similar benefit of the combination treatment was observed in the LNCaP prostate xenograft model. In vitro the degree of inhibition of cell proliferation by STX140 was unaffected by oxygen concentrations. In contrast, the inhibition of proliferation by 2DG was enhanced under hypoxia by 20 and 25% in MCF-7 and LNCaP cells, respectively. The combination of STX140 and 2DG in LNCaP cells under normoxia or hypoxia inhibited proliferation to a greater extent than either compound alone. These results suggest that the antiangiogenic and microtubule disruption activities of STX140 may make tumours more susceptible to inhibition of glycolysis by 2DG. This is the first study to show the benefit of combining a microtubule disruptor with 2DG in the two most common solid tumours