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Left atrial appendage occlusion (LAAO) is a structural interventional cardiology procedure that offers several possibilities for the application of additive manufacturing technologies. The literature shows a growing interest in the use of 3D-printed models for LAAO procedure planning and occlusion device choice. This study aims to describe a full workflow to create a 3D-printed LAA model for LAAO procedure planning.

The workflow starts with the patient’s computed tomography diagnostic image selection. Segmentation in a commercial software provides initial geometrical models in standard tessellation language (STL) format that are then preprocessed for print in dedicated software. Models are printed using a commercial stereolithography machine and postprocessing is performed.

Models produced with the described workflow have been used at the Careggi Hospital of Florence as LAAO auxiliary planning tool in 10 cases of interest, demonstrating a good correlation with state-of-the-art software for device selection and improving the surgeon’s understanding of patient anatomy and device positioning.

3D-printed models for the LAAO planning are already described in the literature. The novelty of the article lies in the detailed description of a robust workflow for the creation of these models. The robustness of the method is demonstrated by the coherent results obtained for the 10 different cases studied.

After the collapse of the Bretton Woods fixed exchange rate system in 1971, countries moved towards floating exchange rates, and the expectation was that the requirement for foreign reserves would decrease. However, central banks currently hold more foreign exchange reserves to enhance the credibility of exchange rate policies. The demand for gold, which was the main reserve asset prior the collapse of the Bretton Woods system, has increased as a reserve asset once again following the global financial crisis (GFC) of 2008, given gold’s characteristics as a safe haven asset and a store of value. This study aims to analyse official reserves of four countries, namely, Malaysia, Turkey, KSA and Pakistan. The Black–Litterman model was used to build a new strategic portfolio with optimal allocation to gold. This study shows that all countries under the analyses should increase their gold holdings to preserve the value of the portfolio during times of financial turmoil.

The Black–Litterman model has been used to build a new strategic portfolio with optimal allocation to gold. The study shows that all countries in our analyses suggested increasing their gold holdings to preserve the value of the portfolio during times of financial turmoil.

The study found that countries under the analyses, namely, Turkey, Malaysia, KSA and Pakistan, suggested increasing their official gold holding given the outstanding performance of gold during the GFC.

Research can be further extended by including few more countries from Organisation of Islamic Cooperation such as Qatar and Indonesia.

Emerging economies such as China, India and Russia started to sharply increase their official gold holdings in the aftermath of the GFC. According to recent statistics, central banks of China and Russia have been adding to their gold reserves. Of note, only in few European countries and in the USA, is the share of gold in foreign reserves more than 50%. In the rest of the world, this figure is about 3-5%. The paper elaborates the aforementioned subject and suggests the strategic weight of gold reserve for each country under analysis.