Electromagnetic Waves in Variable Media

Two methods are explained to exactly solve Maxwell's equations where permittivity, permeability and conductivity may vary in space. In the constitutive relations, retardation is regarded. If the material properties depend but on one coordinate, general solutions are derived. If the properties depend on two coordinates, geometrically restricted solutions are obtained. Applications to graded reflectors, especially to dielectric mirrors, to filters, polarizers and to waveguides, plain and cylindrical, are indicated. New foundations for the design of optical instruments, which are centered around an axis, and for the design of invisibility cloaks, plain and spherical, are proposed. The variability of material properties makes possible effects which cannot happen in constant media, e.g. stopping the flux of electromagnetic energy without loss. As a consequence, spherical devices can be constructed which bind electromagnetic waves

Quality of provided care in vascular surgery : outcome assessment & improvement strategies

The aim of this thesis was to evaluate the quality of care in vascular surgery in end-stage renal disease (ESRD) and peripheral arterial occlusive disease (PAOD): intermittent claudication (IC) and critical lower limb ischaemia (CLI) patients. Therefore firstly it focused on the improvement of the quality of perioperative patient management concerning: (1) a systematic review concerning all quality initiatives in vascular surgery was conducted, (2) an assessed of the implementation of established recommended SP measures in patients with PAOD was established and (3) an evaluation of the implementation of a new optimised care protocol (OCP) outlined in a multidisciplinary meeting was done. Then, it further focused mainly on AEs (registration, occurrence, consequences) of PAOD patients. A (1) determination of risk factors for adverse events (AE) occurrence by assessing three different health care facilities was assessed, (2) an evaluation of the occurrence of cardiac AE after primary lower extremity arterial revascularization (LEAR) for CLI in order to evaluate the impact of cardiac AEs on the clinical outcome was done and (3) a calculation of the average estimated total costs of AEs after treatment for PAOD was performed. Furthermore, the thesis focussed on the quality of life (QOL) of PAOD patients after primary LEAR, concerning (1) the role of social support on the outcome and (2) the improvement of functional status after primary LEAR.Astra Zeneca BV Bard Benelux BV B. Braun Medical BV ChipSoft BV Cordis (Johnson & Johnson) Olympus Nederland BV Terumo BeNelux BVUBL - phd migration 201

Estimated impact of maternal vaccination on global paediatric influenza-related in-hospital mortality: A retrospective case series

Background: Influenza virus infection is an important cause of under-five mortality. Maternal vaccination protects children younger than 3 months of age from influenza infection. However, it is unknown to what extent paediatric influenza-related mortality may be prevented by a maternal vaccine since global age-stratified mortality data are lacking. Methods: We invited clinicians and researchers to share clinical and demographic characteristics from children younger than 5 years who died with laboratory-confirmed influenza infection between January 1, 1995 and March 31, 2020. We evaluated the potential impact of maternal vaccination by estimating the number of children younger than 3 months with in-hospital influenza-related death using published global mortality estimates. Findings: We included 314 children from 31 countries. Comorbidities were present in 166 (53%) children and 41 (13%) children were born prematurely. Median age at death was 8·6 (IQR 4·5-16·6), 11·5 (IQR 4·3-24·0), and 15·5 (IQR 7·4-27·0) months for children from low- and lower-middle-income countries (LMICs), upper-middle-income countries (UMICs), and high-income countries (HICs), respectively. The proportion of children younger than 3 months at time of death was 17% in LMICs, 12% in UMICs, and 7% in HICs. We estimated that 3339 annual influenza-related in-hospital deaths occur in the first 3 months of life globally. Interpretation: In our study, less than 20% of children is younger than 3 months at time of influenza-related death. Although maternal influenza vaccination may impact maternal and infant influenza disease burden, additional immunisation strategies are needed to prevent global influenza-related childhood mortality. The missing data, global coverage, and data quality in this study should be taken into consideration for further interpretation of the results. Funding: Bill & Melinda Gates Foundation

Het paracervicale block tijdens de baring

De baring is het enige fysiologische gebeuren dat met pijn gepaard gaat. Dit wordt reeds aangeduid door het Nederlandse woord 11wee" en equivalente woorden in vele andere talen (dolor, douleur, pains, Wehe e.a.). De pijn is aanvankelijk vooral gelocaliseerd in de onderbuik en onder in de rug. In het laatste deel van de ontsluitingsperiade en tijdens de uitdrijving wordt de pijn daarbij ook in de bekkenbodem, de genitalia externa en het rectum aangegeven. De pijn wordt door de barende zichtbaar en hoorbaar tot uitdrukking gebracht door middel van motorische onrust, woorden waarin wanhoop wordt uitgedrukt en vraag naar verlossing (Buytendijk, 1943; van Eps, 1954). Volgens van Eps (1954) en anderen moet de fysiologische pijn tijdens de baring als ''wordingspijn'' worden onderscheiden van de pathologische "verstoringspijn". Er is slechts weinig onderzoek verricht naar factoren, die het optreden en de ernst van baringspijn bepalen. Zeker is wel, dat de pijnbeleving en de uitdrukking ervan samenhangt met de psychische gesteldheid van de barende. Deze psychische gesteldheid wordt in belangrijke mate gevormd door opvoeding en culturele achtergrond (Crawford, 1972; Phillips, 1975; van Eps, 1954). De houding van de zwangere ten opzichte van het toekomstige kind en de opvang door de echtgenoot en de verloskundige ten tijde van de baring zijn eveneens van belang. Behalve psychische factoren zijn ook somatische invloeden van betekenis voor de wijze waarop de baringspijn wordt beleefd en uitgedrukt

Symptomatic Atherosclerosis: the tip of the iceberg

Vascular surgery patients are at increased risk for developing adverse cardiac events, such as myocardial ischemia or infarction, associated with postoperative morbidity and mortality. Perioperative cardiac complications, therefore, remain an area of clinical interest and concern in patients undergoing vascular surgery. Importantly, it has been demonstrated that the great majority of cardiac events in vascular surgery patients are asymptomatic. The high frequency of perioperative cardiac complications reflects the high prevalence of underlying coronary artery disease. Surgical procedures can be classified to be associated with low-risk (<1%), intermediate-risk (1-5%), or high-risk (>5%) for the development of perioperative cardiac complications. Open lower extremity revascularization and open aortic procedures are considered high-risk surgery. Carotid surgery and endovascular aortic aneurysm repair are considered to have intermediate cardiac risk. Over the years, perioperative risk assessment has evolved significantly in order to detect surgical patients with myocardium at risk due to coronary artery disease. Several risk indices have been developed to identify patients at risk, of which the Revised Cardiac Risk index is currently widely used. Cardiac risk factors imbedded in the Revised Cardiac Risk index are (i) ischemic heart disease, (ii) symptomatic heart failure, (iii) cerebrovascular disease, (iv) insulin dependent diabetes mellitus, (v) renal dysfunction, and (vi) high-risk surgery. However, preoperative risk stratification for adverse cardiac outcome using traditional cardiac risk indices is considered suboptimal, indicating the necessity to improve cardiac evaluation before surgery. These days, the physician needs to inform the patient about his or her perioperative risk. When preoperative risk stratification with, for instance, the use of the Revised Cardiac Risk index identifies the patient to have an increased cardiac risk, additional cardiac testing to diagnose or exclude coronary artery disease is warranted