Efficient analysis of high impedance metasurface with an interstitial-currents approach

An efficient surface integral equation approach is proposed for the electromagnetic analysis of multilayered doubly periodic arrays of high impedance surfaces. It makes use of equivalent electric and magnetic currents on the interfaces between layers. Interfaces may be physical or fictitious. In the case where the interfaces are physical, the background medium in a given layer can be treated as a homogeneous unbounded medium for which the computation of Green’s function for an infinite doubly periodic array is sufficient. The resulting method-of-moments matrix has a block-tridiagonal structure, which leads to a computational complexity proportional to the number of layers for both matrix filling and solution. The numerical results from a two-layer high impedance surface prove the accuracy and efficiency of the interstitial-currents approac

Acute Stroke Management in Türkiye: Intravenous Tissue Plasminogen Activator and Thrombectomy NöroTek: Türkiye Neurology Single Day Study

Objective: To reveal the profile and practice in patients with acute stroke who received intravenous tissue plasminogen activator (IV tPA) and/or neuro-interventional therapy in Türkiye. Materials and Methods: On World Stroke Awareness Day, May 10, 2018, 1,790 patients hospitalized in 87 neurology units spread over 30 health regions were evaluated retrospectively and prospectively. Results: Intravenous tPA was administered to 12% of 859 cases of acute ischemic stroke in 45 units participating in the study. In the same period, 8.3% of the cases received neurointerventional treatment. The rate of good prognosis [modified Rankin score (mRS) 0–2] at discharge was 46% in 83 patients who received only IV tPA [age: 67 ± 12 years; National Institutes of Health Stroke Scale (NIHSS): 12 ± 6; hospital stay, 24 ± 29 days]; 35% in 51 patients who underwent thrombectomy (MT) alone (age: 64 ± 13 years; NIHSS: 14.1 ± 6.5; length of hospital stay, 33 ± 31 days), 19% in those who received combined treatment (age: 66 ± 14 years; NIHSS: 15.6 ± 5.4; length of hospital stay, 26 ± 35 days), and 56% of 695 patients who did not receive treatment for revascularization (age: 70 ± 13 years; NIHSS: 7.6 ± 7.2; length of hospital stay, 21 ± 28 days). The symptom-to-door time was 87 ± 53 minutes in the IV treatment group and 200 ± 26 minutes in the neurointerventional group. The average door-to-needle time was 66 ± 49 minutes in the IV tPA group. In the neurothrombectomy group, the door-to-groin time was 103 ± 90 minutes, and the TICI 2b-3 rate was 70.3%. In 103 patients who received IV tPA, the discharge mRS 0–2 was 41%, while the rate of mRS 0–1 was 28%. In 71 patients who underwent neurothrombectomy, the mRS 0–2 was 31% and mRS 0–1 was 18%. The door-to-groin time was approximately 30 minutes longer if IV tPA was received (125 ± 107 and 95 ± 83 minutes, respectively). Symptomatic bleeding rates were 4.8% in IV recipients, 17.6% among those who received only MT, and 15% in combined therapy. Globally, the hemorrhage rate was 6.8% in patients receiving IV tPA and 16.9% in MT. Conclusion: IV thrombolytic and neurointerventional treatment applications in acute ischemic stroke in Türkiye can provide the anticipated results. Heterogeneity has begun to be reduced in our country with the dissemination of the system indicated by the “Directive on Health Services to be Provided to Patients with Acute Stroke.”. © Copyright 2023 by the Turkish Neurological Society / Turkish Journal of Neurology published by Galenos Publishing House

Pediatric kidney care experience after the 2023 Turkey/Syria earthquake.

Background. Two earthquakes on 6 February 2023 destroyed 10 cities in Türkiye. We report our experience with pediatric victims during these catastrophes, with a focus on crush syndrome related-acute kidney injury (Crush-AKI) and death. Method. Web-based software was prepared. Patient demographics, time under rubble (TUR), admission laboratory data, dialysis, and kidney and overall outcomes were recorded. Results. A total of 903 injured children (median age 11.62 years) were evaluated. Mean TUR was 13 h (interquartile range 32.5, max 240 h). Thirty-one of 32 patients with a TUR of > 120 h survived. The patient who was rescued after 10 days survived. Two-thirds of the patients were given 50 mEq/L sodium bicarbonate in 0.45% sodium chloride solution on admission day. Fifty-eight percent of patients were given intravenous fluid (IVF) at a volume of 2000-3000 mL/m2 body surface area (BSA), 40% at 3000-4000 mL/m2 BSA and only 2% at > 4000 mL/m2 BSA. A total of 425 patients had surgeries, and 48 suffered from major bleeding. Amputations were recorded in 96 patients. Eighty-two and 66 patients required ventilator and inotropic support, respectively. Crush-AKI developed in 314 patients (36% of all patients). In all, 189 patients were dialyzed. Age > 15 years, creatine phosphokinase (CK) =20 950 U/L, TUR =10 h and the first-day IVF volume 20 950 U/L, but not with death. Adolescent age and initial IVF of less than 3000-4000 mL/m2 BSA were also associated with Crush-AKI. Given that mildly injured victims can survive longer periods in the disaster field, we suggest uninterrupted rescue activity for at least 10 days