Clinical applications of perfusion computed tomography, diffusion-weighted magnetic resonance and perfusion-weighted magnetic resonance imaging in detection of early lesions in ischemic stroke

Metody obrazowania ośrodkowego układu nerwowego (OUN), a w szczególności tomografia komputerowa (CT, computed tomography) i rezonans magnetyczny (MR, magnetic resonace) ostatnio bardzo intensywnie się rozwinęły. Takie techniki, jak badanie perfuzyjne CT, MR oraz obrazowanie dyfuzyjne MR, dają zupełnie nowe możliwości w diagnostyce zmian niedokrwiennych mózgu. Te sposoby badania pozwalają uwidocznić ogniska udarów niedokrwiennych w ich najwcześniejszej fazie oraz określić stosunek wielkości strefy zawału i penumbry, co jest cenną informacją w kwalifikacji pacjentów do ewentualnego leczenia trombolitycznego. Celem niniejszej pracy jest przybliżenie możliwości zastosowania nowoczesnych technik diagnostyki we wczesnym okresie udaru niedokrwiennego mózgu.In recent years there has been a rapid development of new imaging methods of central nervous system, based on computed tomography (CT) and magnetic resonance (MR) imaging. Such techniques as CT and MR perfusion as well as diffusion MR create new possibilities in diagnostics of cerebral ischemia. These methods enable to visualize ichemic foci in the very early stage of stroke. Moreover they allow to define the extent of infarction and penumbra areas, which is very important in selecting the candidates for thrombolytic treatment. The aim of this paper is to discuss application of new imaging methods in early stage of ischemic stroke

Mӧssbauer spectroscopy as a useful method for distinguishing between real and false meteorites

In our paper fourMӧssbauer spectra of ordinary chondrites (previously classified by a classical method based on determining the ratio of ferrosilite (Fs) to fayalite (Fa) with an electron microprobe) are presented and discussed. These are the Mӧssbauer spectra of two ordinary chondrites type H (Pultusk and Grzempach), one ordinary chondrite type L (Hyattville) and one type LL (NWA 6287). These meteorites were compared, using their Mӧssbauer spectra with the following four other samples: a fragment of a rock that fell near Leoncin in Poland (sample No. 1), a fragment of a rock found in the vicinity of Pultusk in Poland (sample No. 2), a meteorite specimen bought on the meteorite exchange (sample No. 3) and a stone object whose decline was observed in Europe (sample No. 4). The spectrum of sample No. 1 is very similar to the spectrum of ordinary chondrite of type LL. This observation was confirmed using 4M method (previously created by us). The spectrum of sample No. 2 differs significantly from the spectrum of sample of the Pultusk meteorite. In the spectrum of sample No. 3, a clear signal from iron-nickel alloy and troilite can be observed. This fact allows us to state that sample No. 3 is a fragment of rock that was created in cosmic conditions. Sample No. 4 has a Mӧssbauer spectrum similar to the spectrum of terrestrial magmatic rocks. This observation does not clearly determine where the examined object comes from. This work demonstrates the usefulness of Mӧssbauer spectroscopy in recognizing samples that are fragments of meteorites

4M method-new application of Mössbauer spectroscopy to classification of meteorites. How it works?

4M method is a new application of Mössbauer spectroscopy to quantitative classification of ordinary chondrites. 4M derives from four words: meteorites, Mössbauer spectroscopy, multidimensional discriminant analysis, Mahalanobis distance. This method was published by us in 2019. In this paper we present application of 4M method to classification of four meteorites. Link to script with calculation needed for classification of ordinary chondrites was given

Can Mӧssbauer methods of classifying ordinary chondrites help to identify non-representative samples of these meteorites?

Mössbauer spectra of nonweathered ordinary chondrites consist of four main mineral phases: olivines, pyroxenes, metallic phase and troilite. These minerals represent more than 95% of the whole mass of an ordinary chondrite. Distribution of these mineral phases in micro-scale is not homogeneous. Nevertheless, preparation of representative sample of ordinary chondrite for Mössbauer measurements is possible. To do that a part of 1 g nonweathered material, selected from inside of meteorite without any specific intention is needed. The Warsaw group has been working on investigation of meteorites for 25 years and has analysed about 150 Mössbauer spectra of various meteorites. Among them we found 15 spectra, which could be suspected of being non-representative. These spectra were obtained from Baszkówka, Amber, Bjurböle, Krasnoi-Ugol and Chelyabinsk meteorites. The analysis of how the samples of meteorites were selected for investigation, has shown that the non-representativeness of samples may be due to: intentional choice of sample, preparation of sample from a too small part of material or the use of non-credible source of meteoritic samples. For confirmation of these assumptions, we used a new method of classification of ordinary chondrites – the 4M method. It turned out that this method is a very useful tool for investigation of non-representative samples of equilibrated ordinary chondrites

Crystallographic orientation inhomogeneity and crystal splitting in biogenic calcite

The calcitic prismatic units forming the outer shell of the bivalve Pinctada margaritifera have been analysed using scanning electron microscopy–electron back-scatter diffraction, transmission electron microscopy and atomic force microscopy. In the initial stages of growth, the individual prismatic unit sare single crystals. Their crystalline orientation is not consistent but rather changes gradually during growth. The gradients in crystallographic orientation occurmainly in a direction parallel to the long axis of the prism, i.e. perpendicular to the shell surface anddo not showpreferential tilting along anyof the calcite lattice axes. At a certain growth stage, gradients begin to spread and diverge, implying that the prismatic units split into several crystalline domains. In this way, a branched crystal, inwhich the ends of the branches are independent crystalline domains, is formed. At the nanometre scale, the material is composed of slightly misoriented domains, which are separated by planes approximately perpendicular to the c-axis. Orientational gradients and splitting processes are described in biocrystals for the first time and are undoubtedly related to the high content of intracrystalline organic molecules, although the way in which these act to induce the observed crystalline patterns is amatter of future research

Use of diatoms in forensics

Okrzemki ze względu na powszechność występowania w środowiskach wodnych mogą być wykorzystywane w kryminalistyce w wielu aspektach. Te jednokomórkowe organizmy są przydatne nie tylko do wsparcia diagnozy, że przyczyną śmierci było utonięcie, lecz także do potwierdzenia, czy zbiornik wodny, w którym ujawniono zwłoki, jest tym samym, w którym doszło do utonięcia. Analiza składu ilościowego i jakościowego okrzemek na odzieży oraz na obuwiu może posłużyć do potwierdzenia lub obalenia wersji kryminalistycznych oraz ustalenia, czy konkretna osoba mogła mieć kontakt z określonym środowiskiem wodnym. Cechą predysponującą okrzemki do wykorzystania w kryminalistyce jest trwała i odporna na większość związków chemicznych oraz na wysoką temperaturę ściana komórkowa nazywana pancerzykiem. Pancerzyk ten można izolować z wielu podłoży, poddając je ekstrakcji różnymi metodami, a ze względu na jego specyficzne cechy morfologiczne – wielkość, kształt, ornamentację – ustalić, z jakimi gatunkami okrzemek mamy do czynieniaDue to the common occurrence in aquatic environments, diatoms may be used in forensics in many aspects. These single-celled organisms are useful not only to support the diagnosis that the cause of death was drowning, but also to confirm whether the reservoir in which the corpse was found is the same as the one in which drowning has occurred. Quantitative and qualitative analysis of diatoms present on clothing and footwear can be used to confirm or refute forensic hypotheses and to determine whether a particular person has had contact with a particular water environment. The characteristics that predisposes diatoms to be used in forensics is a cell wall called a frustules – durable and resistant to most chemical compounds and to high temperature. The frustules can be recovered from many types of surfaces by different extraction methods, and based on its specific morphological characteristics, such as size, shape, ornamentation, the particular species of diatom can be identified

Does occurrence of diatoms in internal organs always prove a case of drowning

Okrzemki (Bacillariophyta) to jednokomórkowe organizmy zasiedlające ekosystemy wodne i siedliska wilgotne na całej Ziemi. Wśród tej zróżnicowanej gatunkowo grupy glonów są takie, które występują kosmopolitycznie, lecz są również gatunki, których występowanie jest ograniczone do specyficznych warunków środowiska – gatunki stenotopowe. Okrzemki wyróżniają się unikatową ścianą komórkową, tworzącą tzw. skorupkę, której struktura stanowi podstawę do ich rozróżnienia gatunkowego i jest odporna na działanie większości czynników środowiskowych niszczących inne glony. Ze względu na powyższe cechy okrzemki zostały włączone do postępowań kryminalistycznych i mogą być rozstrzygającą składową postępowania, wskazującą utonięcie jako przyczynę śmierci. W tych przypadkach istotne staje się udzielenie odpowiedzi na pytanie, czy występowanie okrzemek w narządach wewnętrznych zwłok osób znalezionych w wodzie zawsze świadczy o utonięciu. W niniejszej publikacji wykorzystano protokoły sądowo-lekarskich oględzin zwłok oraz protokoły badania na obecność okrzemek w organach wewnętrznych, sporządzone w latach 2013–2017 w Zakładzie Medycyny Sądowej Warszawskiego Uniwersytetu Medycznego, który jest obecnie jedynym ośrodkiem w Polsce przeprowadzającym rutynowo test okrzemkowy. Wykazano, że pozytywny wynik testu okrzemkowego pokrywa się ze wskazaniami przyczyny śmierci z sądowo-lekarskich protokołów oględzin zwłok. Jedynie w pojedynczych, dających się wytłumaczyć przypadkach wyniki testu okrzemkowego nie potwierdzają opinii z sekcji sądowo-lekarskiej, wykluczającej utonięcie jako przyczynę zgonu.Diatoms (Bacillariophyta) are unicellular algae inhabiting in aquatic ecosystems and marsh habitats on the entire Earth. This group of algae, variable in terms of species, comprises both cosmopolitan ones but also those whose occurrence is limited to specific environmental conditions, i.e. stenotopic species. Diatoms are distinguished by unique cell walls making so-called, frustules, whose structures constitute the bases for differentiation between species. Frustules are resistant to the majority of environmental conditions that destroy other algae. Due to the above characteristics diatoms have been incorporated in forensic investigations and they can be the conclusive component of the proceedings by indicating drowning as the cause of death. In those cases, it is important to answer the question whether finding diatoms in internal organs of corpses found in water always proves drowning. The publication uses reports from forensic medical examinations of corpses and reports from detecting presence of diatoms in internal organs performed in years 2013-2017 in the Institute of Forensic Medicine of Warsaw Medical University, which is presently the only centre in Poland that routinely performs the diatom test. It has been demonstrated that a positive result of the diatom test generally coincides with the conclusive indications of the cause of death in the forensic medical autopsy reports. Only in few individual well-explainable cases the results of the diatom tests did not confirm conclusions from the forensic autopsies, which excluded drowning as the cause of death

With Mössbauer effect on Mars

People have been trying to send space vehicles to Mars since the early 1960s to explore the surface of this planet. One of the most important missions in discovering Mars was the Viking mission of 1975, which provided a lot of information shaping knowledge about the red planet at the turn of the century. The idea of sending Mössbauer spectrometer to Mars appeared due to the prevalence of iron in the planet's surfce and due to the specific properties of Mössbauer spectroscopy. Our paper describes the Warsaw project to send a Mössbauer spectrometer (MARMOS) to Mars and the project suggested by scientists from Mainz University (MIMOS II). A special Mössbauer spectrometer was constructed for the MER mission by West European Team. The paper presents the possibilities of using a miniaturized Mössbauer spectrometer for the investigation of archeological artefacts. The Mössbauer spectra obtained on the surface of Mars were discussed. The Mössbauer spectra obtained on the surface of Mars were discussed. The Mössbauer spectra measured on Mars are characterized by three doublets and one or two magnetic sextets. The spectra consist of a Fe3+ doublet (assigned to nanophase ferric oxide), two Fe2+ doublets (assigned to olivine and pyroxen) and two sextets (assigned to nonstoichiometric magnetite) or one sextet (assigned to a hematite-like phase)