Mathematical Foundations of the Non-Hermitian Skin Effect.

We study the skin effect in a one-dimensional system of finitely many subwavelength resonators with a non-Hermitian imaginary gauge potential. Using Toeplitz matrix theory, we prove the condensation of bulk eigenmodes at one of the edges of the system. By introducing a generalised (complex) Brillouin zone, we can compute spectral bands of the associated infinitely periodic structure and prove that this is the limit of the spectra of the finite structures with arbitrarily large size. Finally, we contrast the non-Hermitian systems with imaginary gauge potentials considered here with systems where the non-Hermiticity arises due to complex material parameters, showing that the two systems are fundamentally distinct.

[An Unusual Hemisphere Syndrome]. / Ein nicht alltägliches Hemisyndrom.

An Unusual Hemisphere Syndrome Abstract. A patient with known hereditary hemorrhagic telangiectasia presents with transient right arm weakness and dizziness. A transient ischemic attack is diagnosed on clinical and risk factors. In the course of the disease, the patient suffers a convulsive event and fever occurs twice without a clear focus on the infection. The initial skull MRI shows a centroparietal lesion on the left with signs of accompanying edema. Due to this unusual concomitant edema, a neoplastic event must also be considered for differential diagnosis. However, the further examinations show no evidence of neoplasia, but the course MRI of the skull shows the image of septic embolisms with a brain abscess. After neurosurgical remediation and appropriate antibiotic treatment, the clinical course is pleasing. The cause of the septic embolisms was a pulmonary arteriovenous malformation due to hereditary hemorrhagic telangiectasia, which could be coiled without complications.

Single-center experience with the combination of Cardioplexol™ cardioplegia and MiECC for isolated coronary artery bypass graft procedures.

BACKGROUND: Cardioplexol™ with its low volume (100 mL) was originally conceived as cardioplegic solution for MiECC procedures. Introduced in its current form in 2008 in our clinic, it has immediately demonstrated attractive advantages including the easy and rapid administration by the surgeon him/herself, the almost immediate cardiac arrest and a prolonged delay before a second dose is necessary. We report here the results of our initial experience with this simple solution. METHODS: Single centre, retrospective observational analysis of prospectively collected data of isolated coronary artery bypass graft (CABG) procedures performed with a MiECC. RESULTS: Of 7,447 adult cardiac surgical operations performed during a 76 months period, 2,416 were isolated CABG-MiECC procedures. Patients were 81.3% males, 66.2±9.7 years old and had a median logistic EuroSCORE of 3.2. In average 3.2±0.8 vessels were bypassed. Median cross-clamp time was 45 minutes and more than 75% of the patients received only one 100 mL dose of Cardioplexol™. At reperfusion more than 90% of the hearts spontaneously recovered a rhythmic activity. Maximal value of troponin T during the first hours following myocardial reperfusion was 0.9±4.5 ng/mL (median =0.4 ng/mL). Mortality at 30 days was 0.9%. CONCLUSIONS: Cardioplexol™ seems very promising. It appears especially efficient and safe when used for CABG procedures performed with a MiECC.