Quantum phase slip interference device based on superconducting nanowire

We propose a transistor-like circuit including two serially connected segments of a narrow superconducting nanowire joint by a wider segment with a capacitively coupled gate in between. This circuit is made of amorphous NbSi film and embedded in a network of on-chip Cr microresistors ensuring a sufficiently high external electromagnetic impedance. Assuming a virtual regime of quantum phase slips (QPS)in two narrow segments of the wire, leading to quantum interference of voltages on these segments, this circuit is dual to the dc SQUID. Our samples demonstrated appreciable Coulomb blockade voltage (analog of critical current of the SQUIDs) and periodic modulation of this blockade by an electrostatic gate (analog of flux modulation in the SQUIDs). The model of this QPS transistor is discussed.Comment: 5 pages including 3 figures; in v2 the title was updated, typos were fixed and 4 references adde

Normal metal - insulator - superconductor interferometer

Hybrid normal metal - insulator - superconductor microstructures suitable for studying an interference of electrons were fabricated. The structures consist of a superconducting loop connected to a normal metal electrode through a tunnel barrier . An optical interferometer with a beam splitter can be considered as a classical analogue for this system. All measurements were performed at temperatures well below 1 K. The interference can be observed as periodic oscillations of the tunnel current (voltage) through the junction at fixed bias voltage (current) as a function of a perpendicular magnetic field. The magnitude of the oscillations depends on the bias point. It reaches a maximum at energy $eV$ which is close to the superconducting gap and decreases with an increase of temperature. Surprisingly, the period of the oscillations in units of magnetic flux $\Delta \Phi$ is equal neither to $h/e$ nor to $h/2e$, but significantly exceeds these values for larger loop circumferences. The origin of the phenomena is not clear.Comment: 11 pages and 8 figure

Microscopic model for multiple flux transitions in mesoscopic superconducting loops

A microscopic model is constructed which is able to describe multiple magnetic flux transitions as observed in recent ultra-low temperature tunnel experiments on an aluminum superconducting ring with normal metal - insulator - superconductor junctions [Phys. Rev. B \textbf{70}, 064514 (2004)]. The unusual multiple flux quantum transitions are explained by the formation of metastable states with large vorticity. Essential in our description is the modification of the pairing potential and the superconducting density of states by a sub-critical value of the persistent current which modulates the measured tunnel current. We also speculate on the importance of the injected non-equilibrium quasiparticles on the stability of these metastable states.Comment: 6 pages, 3 figure

Delay to Surgery of Less Than 12 Hours Is Associated With Improved Short- and Long-Term Survival in Moderate- to High-Risk Hip Fracture Patients

Introduction: The effect of delays before surgery of 24 hours, 48 hours, and 72 hours on short- and long-term survival has been investigated comprehensively in hip fracture patients, but with controversial results. However, there is only limited evidence for how a threshold of 12-hour delay before hip fracture surgery affects survival. Materials and Methods: A prospective observational study of 884 consecutive hip fracture patients (age >= 65 years) undergoing surgery was carried out in terms of 30- and 365-day survival. A Cox hazard regression survival model was constructed for 724 patients with American Society of Anesthesiologists score >= 3 with adjustments of age, gender, cognition, number of medications on admission, hip fracture type, and prior living arrangements. Results: Patients who underwent surgery within 12 hours had better chances of survival than did those with 12 to 24 hours (hazard ratio [HR]: 8.30; 95% confidence interval [CI]: 1.13-61.4), 24 to 48 hours (HR: 7.21; 95% CI: 0.98-52.9), and >48 hours (HR: 11.75; 95% CI: 1.53-90.2) delay before surgery. Long-term survival was more influenced by nonadjustable patient features, but the adverse effect of >48 hours delay before surgery was noticed with HR: 2.02; 95% CI: 1.08-3.80. Increased age and male gender were significantly associated with worse short- and long-term survival. Discussion/Conclusions: Early hip fracture surgery within 12 hours of admission is associated with improved 30-day survival among patients with ASA score >= 3. Delay to surgery of more than 48 hours has an adverse effect on 365-day survival, but factors related to patients' comorbidities have a great influence on long-term survival

Does cognitive/physical screening in an outpatient setting predict institutionalization after hip fracture?

BACKGROUND: Institutionalization after hip fracture is a socio-economical burden. We examined the predictive value of Instrumental Activities of Daily Living (IADL) and Mini Mental State Examination (MMSE) for institutionalization after hip fracture to identify patients at risk for institutionalization. METHODS: Fragility hip fracture patients ≥65 years of age (n = 584) were comprehensively examined at a geriatric outpatient clinic 4 to 6 months after surgery and followed 1 year postoperatively. A telephone interview with a structured inquiry was performed at 1, 4, and 12 months after hip fracture. RESULTS: Age-adjusted univariate logistic regression analysis revealed that IADL and MMSE scores measured at the outpatient clinic were significantly associated with living arrangements 1 year after hip fracture. Multivariate logistic regression analysis established that institutionalization 1 year after hip fracture was significantly predicted by institutionalization at 4 months (odds ratio [OR] 16.26, 95 % confidence interval [CI] 7.37-35.86), IADL <5 (OR 12.96, 95 % CI 1.62-103.9), and MMSE <20 (OR 4.19, 95 % CI 1.82-9.66). A cut-off value of 5 was established for IADL with 100 % (95 % CI 96 %-100 %) sensitivity and 38 % (95 % CI 33 %-43 %) specificity and for MMSE, a cut-off value of 20 had 83 % (95 % CI 74 %-91 %) sensitivity and 65 % (95 % CI 60 %-70 %) specificity for institutionalization. During the time period from 4 to 12 months, 66 (11 %) patients changed living arrangements, and 36 (55 %) of these patients required more supportive accommodations. CONCLUSION: IADL and MMSE scores obtained 4 to 6 months after hospital discharge may be applicable for predicting institutionalization among fragility hip fracture patients ≥65 years of age at 1 year after hip fracture. An IADL score of ≥5 predicted the ability to remain in the community. Changes in living arrangements also often occur after 4 months.BioMed Central open acces

Factors associated with and 1-year outcomes of fear of falling in a geriatric post-hip fracture assessment

Background: Hip fracture causes not only physical injury but also psychological trauma. Fear of falling (FoF) is related to poor recovery, loss of mobility and mortality. There is limited data on the clinical factors affecting post-hip fracture FoF and its consequences. Objective: To investigate the factors associated with and 1-year outcomes of post-hip fracture FoF. Methods: An observational prospective cohort study. Data were collected on hospital admission, at a geriatric outpatient assessment 4–6 months post-hip fracture and by telephone interviews 1 year after the index fracture. FoF was assessed with a dichotomous single-item question. Logistic regression analyses were conducted to examine the age, gender and multivariable-adjusted association between baseline and the geriatric assessment domains with FoF. Follow-up outcomes included changes in mobility, living arrangements and mortality. Results: Of the 916 patients included, 425 (49%) had FoF at the time of their geriatric assessment. These patients were predominantly female and were living alone in their own homes with supportive home care. They scored lower on tests of physical performance. Less FoF was documented in patients with diagnosed cognitive disorders before the index fracture and in those with Clinical Dementia Rating ≥ 1. After adjusting for age and gender, no association was observed between FoF and any of the 1-year follow-up outcomes. Conclusion: Post-hip fracture FoF is common and associated with female gender, polypharmacy, poor daily functioning, poor physical performance and depressive mood. Patients with cognitive disorders have less FoF than those without. FoF appears to have no impact on the follow-up outcomes.publishedVersionPeer reviewe

Factors associated with and 1-year outcomes of fear of falling in a geriatric post-hip fracture assessment

Background Hip fracture causes not only physical injury but also psychological trauma. Fear of falling (FoF) is related to poor recovery, loss of mobility and mortality. There is limited data on the clinical factors affecting post-hip fracture FoF and its consequences. Objective To investigate the factors associated with and 1-year outcomes of post-hip fracture FoF. Methods An observational prospective cohort study. Data were collected on hospital admission, at a geriatric outpatient assessment 4-6 months post-hip fracture and by telephone interviews 1 year after the index fracture. FoF was assessed with a dichotomous single-item question. Logistic regression analyses were conducted to examine the age, gender and multivariable-adjusted association between baseline and the geriatric assessment domains with FoF. Follow-up outcomes included changes in mobility, living arrangements and mortality. Results Of the 916 patients included, 425 (49%) had FoF at the time of their geriatric assessment. These patients were predominantly female and were living alone in their own homes with supportive home care. They scored lower on tests of physical performance. Less FoF was documented in patients with diagnosed cognitive disorders before the index fracture and in those with Clinical Dementia Rating >= 1. After adjusting for age and gender, no association was observed between FoF and any of the 1-year follow-up outcomes. Conclusion Post-hip fracture FoF is common and associated with female gender, polypharmacy, poor daily functioning, poor physical performance and depressive mood. Patients with cognitive disorders have less FoF than those without. FoF appears to have no impact on the follow-up outcomes.</p

Hypoalbuminemia is a frequent marker of increased mortality in cardiogenic shock

Altres ajuts: VPH was supported by the Aarne Koskelo Foundation (no grant number): http://www. aarnekoskelonsaatio.fi/, and the Finnish Cardiac Foundation (no grant number): https://www. fincardio.fi/. Laboratory kits were provided by Roche Diagnostics. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Introduction The prevalence of hypoalbuminemia, early changes of plasma albumin (P-Alb) levels, and their effects on mortality in cardiogenic shock are unknown. Materials and methods P-Alb was measured from serial blood samples in 178 patients from a prospective multinational study on cardiogenic shock. The association of hypoalbuminemia with clinical characteristics and course of hospital stay including treatment and procedures was assessed. Theprimary outcome was all-cause 90-day mortality. Results Hypoalbuminemia (P-Alb < 34g/L) was very frequent (75%) at baseline in patients with cardiogenic shock. Patients with hypoalbuminemia had higher mortality than patients with normal albumin levels (48% vs. 23%, p = 0.004). Odds ratio for death at 90 days was 2.4 [95% CI 1.5-4.1] per 10 g/L decrease in baseline P-Alb. The association with increased mortality remained independent in regression models adjusted for clinical risk scores developed for cardiogenic shock (CardShock score adjusted odds ratio 2.0 [95% CI 1.1-3.8], IABPSHOCK II score adjusted odds ratio 2.5 [95%CI 1.2-5.0]) and variables associated with hypoalbuminemia at baseline (adjusted odds ratio 2.9 [95%CI 1.2-7.1]). In serial measurements,albumin levels decreased at a similar rate between 0h and 72h in both survivors andnonsurvivors (ΔP-Alb -4.6 g/L vs. 5.4 g/L, p = 0.5). While the decrease was higher for patients with normal P-Alb at baseline (p 0.001 compared to patients with hypoalbuminemia at baseline), the rate of albumin decrease was not associated with outcome. Conclusions Hypoalbuminemia was a frequent finding early in cardiogenic shock, and P-Alb levels decreased during hospital stay. Low P-Alb at baseline was associated with mortality independently of other previously described risk factors. Thus, plasma albumin measurement should be part of the initial evaluation in patients with cardiogenic shock