The anatomy of the tympanic sinus

The tympanic sinus is one of the most important structures of the human temporal bone. Located in its vicinity are the round window, posterior semicircular canal and facial nerve. The study was performed on 30 temporal bones taken from adult cadavers of both sexes. After the tympanic sinus had been identified, its morphological features were evaluated. The sinus was then measured using a graticule with an accuracy of 0.05 mm. Also measured were the shortest distances from the tympanic sinus to the neighbouring structures (the lateral and posterior semicircular canal, the facial nerve canal and the jugular fossa). The measurements were performed under a surgical microscope with eye-piece graduation of 0.05 mm accuracy. Four main morphological types of fossa of the tympanic sinus and two main developmental forms, a deep sinus and a shallow sinus, were distinguished. The existence of a deep sinus was associated with absence of the bridge and the sinus was shallower when the bridge was prominent. The very deep sinuses were located close to the facial canal, in some cases penetrating deep in its vicinity (in some cases even going beyond two thirds of the canal’s circumference), which poses a real risk of facial nerve damage during surgical removal of a lesion located in close proximity to the nerve. In most cases the tympanic sinus is elliptical in shape and its long diameter lies in the vertical plane (mean value: 2.73 × 2.23 mm). The mean distances from the tympanic sinus to the facial nerve canal, lateral semicircular canal, posterior semicircular canal and jugular fossa were 1.5 mm, 2.1 mm, 1.59 mm and 5.5 mm respectively. No correlation was observed between the measurement results and either sex or side

Modelling of endoprostheses – applications of 3D and 5D printers in medicine

Praca przedstawia autorskie podejścia do modelowania powłok oraz obiektów wolumetrycznych o porowatej strukturze, wytwarzanych za pomocą drukarek 3D i 5D, które mogą być wykorzystane jako endoprotezy w zastosowaniach medycznych. W pierwszej kolejności zaproponowano generowanie otwartych oraz częściowo zamkniętych powłok opartych na trzech rodzajach siatek: trójkątnej, czworokątnej i heksagonalnej. Dla tej ostatniej, korzystając z notacji Bravisa, podano trzy równania generujące struktury Armchair, Chiral, Zig-zag. Dla wolumetrycznych obiektów porowatych rozważano metody wytwarzania bazujące na strukturach krystalograficznych oraz parametrycznych funkcjach generacyjnych. Zaproponowano optymalizację kształtu przestrzennych łączników, które opisano analitycznymi powierzchniami czwartego rzędu, poprawiających własności mechaniczne struktury. Dla powłok przeprowadzono szacowanie kosztów wykonania przedmiotu biorąc pod uwagę ilość zużytego materiału. Opisano również etapy procesu przetwarzania danych od momentu wczytania pliku STL (niezwiązana lista trójkątów) do wytworzenia zapisu poleceń (w standardzie G-code) dla drukarki 3D. Zasygnalizowano również tematykę technologii druku 5D przewidzianą do realizacji na nowatorskiej drukarce 5D.The paper presents original modelling approaches to the shells and volumetric porous structures produced by the application of 3D and 5D printers. These devices can be used to create endoprosthesis for medical applications. Based on the three types of meshes: triangular, rectangular, and hexagonal, the problem of generating open and partially closed shells has been considered. For porous volumetric structures the parametric generative function uses BRAVIS notation and crystallographic structures has been formed. To improve the mechanical properties of the structure, the shape of the all nodes has been replaced by local fourth order analytical surfaces. Proposed modeling method takes into account the cost of manufacturing and amount of used material. The paper also describes the stages of the STL data processing starting from the file loading (unbound list of triangles) to generating control commands (standard G-code) for a 3D printer. Some problems referring to the innovative printing technology 5D has been also described

Synthesis and crystal structure of new compounds from the Y–Mg–Ni system

International audienceThe synthesis, structural characterization, and chemical bonding peculiarities of new intermetallic compounds from Y–Mg–Ni ternary system are reported herein. The crystal structures of these compounds were determined by single-crystal and X-ray powder diffraction analysis. Three ternary compounds were studied: Y2Mg11Ni2 [own structure type, monoclinic, Pearson Symbol mS30, Space Group C2/m, a = 18.969(4), b = 3.6582(7), c = 11.845(2) Å, β = 125.07(3)°], Y4Mg3Ni2 [Ru4Al3B2 structure type, tetragonal, P4/mmm, tP18, a = 10.8668(2), c = 3.59781(12) Å] and YMgNi [MoAlB structure type, orthorhombic, Cmcm, a = 3.6713(4), b = 17.708(3), c = 3.9583(5) Å]. New compositions of Y1−xMgxNi4 and Y5−xMg24+x solid solutions were detected: YMg0.86(1)Ni4.14(1) [SnMgCu4 structure type, cubic, F4̅3m, cF24, a = 7.0747(6) Å] and Y4.28(1)Mg24.72(1) [Ti5Re24 structure type, cubic, I4̅3m, cI58, a = 11.2655(11) Å]. The crystal structure peculiarities of these compounds are discussed. A particular attention has been given to Y2Mg11Ni2 and its relations with other Mg-containing compounds. Crystallographic analysis together with linear muffin-tin orbital band structure calculations reveals the presence of [Y2Ni4@Mg20] and [Y4Ni2@Mg18] clusters in Y2Mg11Ni2phase. For Y4Mg3Ni2 the formation of the Ni–Mg nets was observed, while the Y atoms form a monolayer