NON-INVASIVE ANALYSIS AND VISUALIZATION OF OBJECTS FROM FSW AlSi9Mg/2017A ALUMINUM ALLOY JOINTS

Friction stir welding (FSW) technology allows for the welding of materials that differ in their chemical compositions, microstructures, and properties. When selecting the parameters, it is necessary to analyze the structure of a weld and eliminate the defects. The use of X-ray microtomography creates the possibility of precise imaging of a joint structure – especially when it contains defects (voids). The tests were carried out on an FSW joint made with both 2017A and AlSi9Mg aluminum alloys. The macrostructure was cross-sectional, and a defect was found in the middle part of the joint and on the advancing side. We used a conventional method of observation light microscopy. Then, an analysis was performed using X-ray microtomography, which revealed the shape of the defect in 3D. Individual cross-sections were extracted, which enabled us to measure the geometric quantities. A dependence was found for the shape of the defect on the welding parameters and the variability of its construction. The usefulness of this advanced material imaging technology for the analysis of FSW welds has been confirmed

Improved Methods for Preserving Macromolecular Structures and Visualizing Them by Fluorescence and Scanning Electron Microscopy

To determine the optimal procedures to preserve cytoskeletal and other macromolecular structures for microscopic studies we have evaluated the effects of various methods to extract cultured cells. In this report, we compare results using different fixatives, crosslinking reagents, and permeabilization methods on (1) the labeling of cells for fluorescence microscopy with phalloidin or antibody against tubulin; and (2) the morphological preservation of macromolecular structures for scanning electron microscopy. Maximal labeling of F-actin with phalloidin was obtained by fixing cells in 4% para formaldehyde (PFA) and labeling the unextracted cells with methanolic phalloidin, whereas maximal labeling of tubulin required prefixation with either PFA or the bi functional protein crosslinking reagent, dithiobis (succinimidylpropionate) (DSP) and extraction with ethanol or Triton in a high salt buffer. However, for both qualitative and quantitative light and electron microscopic studies of intracellular macromolecular structures, prefixation with DSP and extracting with Triton X-100 in a stabilizing buffer is the overall method of choice for both labeling and morphological studies. Although other methods provide maximal labeling or preservation of specific structures, this method provides excellent preservation of morphological structure while allowing proteins to be preserved and labeled by specific probes

Wyzwania modernizacyjne służby cywilnej w Polsce

Modernisation Challenges of the Polish Civil ServiceThe main objective of this article is to identify and characterise the main – according to the author – modernisation challenges that the civil service in Poland is facing. Considerations and proposals arise from the analysis of the existing legal standards and operational practices of the Polish civil service, including as well conclusions derived from personal experience of the author who has held managerial positions in governmental administration units. For that reason, the proposed solutions, based on the systemic and legal analysis but also the practice of one of the key internal stakeholders of the civil service system. Certainly, the highlighted challenges do not exhaust the entire catalogue of possible modernisation solutions, yet the author’s main goal was to present abroad view of the subject matter in order to discuss the key challenges for the civil service in Poland

Neurofibromatosis type 1 in an adult diagnosed by a pulmonologist

Nerwiakowłókniakowatość typu 1 jest częstą chorobą genetyczną wynikającą z braku białka neurofibrominy i w konsekwencji prowadzącą do różnych nieprawidłowości w obrębie obwodowego i ośrodkowego układu nerwowego, a także w innych narządach. Najczęściej rozpoznawana jest przez pediatrów w wieku dziecięcym. Zdarza się, że pozostaje nierozpoznana lub rozpoznana dopiero w wieku dorosłym. W niniejszej pracy przedstawiamy 32-letnią chorą, u której nerwiakowłókniakowatość typu 1 rozpoznano po skierowaniu jej do pulmonologa z podejrzeniem guza płuca lewego. Chorą przyjęto do Kliniki Pulmonologii do diagnostyki zacienienia w lewym płucu, stwierdzonego w badaniu rentgenowskim klatki piersiowej. W badaniu przedmiotowym stwierdzono na skórze ciała kilka plamistych przebarwień oraz guzków, które histologicznie okazały się nerwiakowłókniakami. Dalsza diagnostyka, obejmująca TK i PET klatki piersiowej oraz badanie okulistyczne, pozwoliła na rozpoznanie nerwiakowłókniakowatości typu 1.Neurofibromatosis type 1 (NF1), referred to as von Recklinghausen’s disease, is a genetic disorder triggered by mutation of the NF1 gene, resulting in a lack of neurofibromin, which leads to abnormalities found in the peripheral nervous system and central nervous system, as well as in other organs. The disease is diagnosed early, usually in childhood by pediatricians. However, in some cases, the disease is clinically silent and remains undiagnosed or is recognized in the late adulthood. We report a case study of a 32-year-old female, who was referred to the pulmunologist with a suspicion of a lung tumor. The patient was admitted to the Pulmonology Department to investigate further the subpleural mass localized in the left lung found by chance in a chest X-ray. Physical examination revealed café-au-lait spots on her skin, several subcutaneous nodules which were confirmed by a histopathology to be consistent with neurofibroma. Further diagnostic testing, such as chest CT, PET and ophthalmological examination, led to diagnosis of neurofibromatosis type 1 with pulmonary involvement

X-ray microtomography analysis of the aluminum alloy composite reinforced by SiC after Friction Stir Processing

Despite many years of using friction stir processing (FSP), there are many unexplained aspects concerning the processes which appear during FSP: determining the direction of flow and mixing of the materials and the degree of mixing and microstructure fragmentation in specific areas. This paper presents the impact of FSP on the micro- and macrostructure of the composite with hypo-eutectic Si matrix reinforced by SiC particles. The analysis of the structure of the processed area in FSP in the relation to the microstructure of the base material has been made using x-ray microtomography. The results of these studies have been juxtaposed with studies using microscopic methods (light microscopy and SEM). The microtomography images revealed an additional separation on the advancing side and the weld nugget, where on the basis of a 3D reconstruction a layer microstructure on the direction of linear movement of the tool has been demonstrated. The analyses have revealed a limited flow of the material above the weld nugget. The main advantages of the research method applied were the possibility to show the invisible or barely visible elements of the microstructure using standard test methods and the ability to analyze the microstructure changes uninterruptedly in different directions in the volume of the material