Conjugate times and regularity of the minimum time function with differential inclusions

This paper studies the regularity of the minimum time function, $T(\cdot)$, for a control system with a general closed target, taking the state equation in the form of a differential inclusion. Our first result is a sensitivity relation which guarantees the propagation of the proximal subdifferential of $T$ along any optimal trajectory. Then, we obtain the local $C^2$ regularity of the minimum time function along optimal trajectories by using such a relation to exclude the presence of conjugate times

Towards two-dimensional metallic behavior at LaAlO3/SrTiO3 interfaces

Using a low-temperature conductive-tip atomic force microscope in cross-section geometry we have characterized the local transport properties of the metallic electron gas that forms at the interface between LaAlO3 and SrTiO3. At low temperature, we find that the carriers do not spread away from the interface but are confined within ~10 nm, just like at room temperature. Simulations taking into account both the large temperature and electric-field dependence of the permittivity of SrTiO3 predict a confinement over a few nm for sheet carrier densities larger than ~6 10^13 cm-2. We discuss the experimental and simulations results in terms of a multi-band carrier system. Remarkably, the Fermi wavelength estimated from Hall measurements is ~16 nm, indicating that the electron gas in on the verge of two-dimensionality.Comment: Accepted for publication in Physical Review Letter

Cancer patients’ experiences of error and consequences during diagnosis and treatment

The study objective was to investigate patient experienced error during diagnosis and treatment of cancer. The design included a nationwide patient survey on quality and safety in Danish cancer care. Responses regarding patient experienced error were separately analyzed, quantitative responses using descriptive statistics and qualitative responses using systematic text analysis. Study participants included 6,720 adult patients with a first time diagnosis of cancer registered between May 1st and August 31st 2010. The patients received a questionnaire concerning their experiences of care received by general practitioners, specialist practitioners and at the hospital. A response rate of 65% was achieved. 10 – 25% of patients experienced error during diagnosis or treatment. 61% reported that hospital errors had consequences. Unexpected surgical errors/complications (27%), delay due to doctors’ assessment errors (24%) and unavailable test results (21%) were the most frequent types of errors identified using closed questions. 819 qualitative responses supplemented this information and revealed errors related to cancer detection, planning & coordination, patient-provider communication, administrative processes and treatment & medication. Physical, psychological, social as well as organizational consequences of the errors were uncovered. Patient experiences of errors suggest that practices related to informed consent, diagnostic reasoning as well as handling of test results, referrals and the medical chart should be further improved. In addition, safety aspects of the patient-provider communication and involvement of patients as an extra safety barrier merit further study

Enzyme amperometric sensor for the determination of cholinesterase inhibitors or activators

An enzyme amperometric sensor (EAS) based on immobilized cholinesterase (ChE) sensitive to ChE effectors (both specific and non-specific) is shown to be useful in enzyme immunoassay. For example, a mink autoimmune (Aleutian) disease can be diagnosed with the EAS when an antigen is labelled with a ChE inhibitor. When the ChE-containing membrane is modified by incorporation of the antigen to give an immunoenzyme EAS, this immunoassay can be performed on the basis of the steric shielding of the enzyme active sites with the immunocomplexes formed. © 1993

Plasmon-pole approximation for semiconductor quantum wire electrons

We develop the plasmon-pole approximation for an interacting electron gas confined in a semiconductor quantum wire. We argue that the plasmon-pole approximation becomes a more accurate approach in quantum wire systems than in higher dimensional systems because of severe phase-space restrictions on particle-hole excitations in one dimension. As examples, we use the plasmon-pole approximation to calculate the electron self-energy due to the Coulomb interaction and the hot-electron energy relaxation rate due to LO-phonon emission in GaAs quantum wires. We find that the plasmon-pole approximation works extremely well as compared with more complete many-body calculations.Comment: 16 pages, RevTex, figures included. Also available at http://www-cmg.physics.umd.edu/~lzheng

Electrical energy by electrode placement for cardioversion of atrial fibrillation: a systematic review and meta-analysis

OBJECTIVE: Electrode patch position may not be critical for success when cardioverting atrial fibrillation (AF), but the relevance of applied electrical energy is unclarified. Our objective was to perform a meta-analysis of randomised trials to examine the dose-response relation between energy level and cardioversion success by electrode position in elective cardioversion.METHODS: We searched PubMed, Embase, The Cochrane Library, Google Scholar and Scopus Citations. Inclusion criteria were randomised controlled trials using biphasic shock waves and self-adhesive patches, and publication date from 2000 to 2023. We used random-effects dose-response models to meta-analyse the relation between energy level and cardioversion success by anterolateral and anteroposterior position. Random-effects models estimated pooled risk ratios (RR) for cardioversion success after the first and the final shocks between the two electrode positions.RESULTS: We included five randomised controlled trials (N=1078). After the first low-energy shock, the electrode position was not significantly associated with the likelihood of successful cardioversion (pooled RR anterolateral vs anteroposterior placement 1.28, 95% CI 0.93 to 1.76, with considerable heterogeneity). After a high-energy final shock, there was no evidence of an association between the electrode position and the cumulative chance of cardioversion success (pooled RR anterolateral vs anteroposterior 1.05, 95% CI 0.97 to 1.14). Regardless of electrode position, cardioversion success was significantly less likely with shock energy levels &lt; 200J compared with 200J.CONCLUSION: Evidence from contemporary randomised trials suggests that higher level of electrical energy is associated with higher conversion rate when cardioverting AF with a biphasic shockwave. Positioning of electrodes can be based on convenience.</p

Social determinants of health and cardiovascular outcomes in patients with heart failure

BackgroundWe examined the associations between family income and educational attainment with incident atrial fibrillation (AF), myocardial infarction (MI), stroke and cardiovascular (CV) death among patients with newly-diagnosed heart failure (HF).MethodsIn a nationwide Danish registry of HF patients diagnosed between 2008 and 2018, we established a cohort for each outcome. When examining AF, MI and stroke, respectively, patients with a history of these outcomes at diagnosis of HF were excluded. We used cause-specific proportional hazard models to estimate hazard ratios for tertile groups of family income and three levels of educational attainment.ResultsAmong 27,947 AF-free patients, we found no association between income or education and incident AF. Among 27,309 MI-free patients, we found that lower income (hazard ratio 1.28 [95% CI 1.11-1.48] and 1.11 [0.96-1.28] for lower and medium vs. higher income) and education (1.23 [1.04-1.45] and 1.15 [0.97-1.36] for lower and medium vs. higher education) were associated with MI. Among 36,801 stroke-free patients, lower income was associated with stroke (1.38 [1.23-1.56] and 1.27 [1.12-1.44] for lower and medium vs. higher income) but not education. Lower income (1.56 [1.46-1.67] and 1.32 [1.23-1.42] for lower and medium vs. higher income) and education (1.20 [1.11-1.29] and 1.07 [0.99-1.15] for lower and medium vs. higher education) were associated with CV death.ConclusionsIn patients with newly-diagnosed HF, lower family income was associated with higher rates of acute MI, stroke and cardiovascular death. Lower educational attainment was associated with higher rates of acute MI and cardiovascular death. There was no evidence of associations between income and education with incident AF