Magnetic properties and structure of the Ni-Co-Mn-In alloys with the boron addition

Series of Ni_{45.5-x}Co_{4.5}Mn_{36.6}In_{13.4}B_{x} (at.%, x=0, 0.05, 0.1, 0.5, 1.0) polycrystalline magnetic shape memory alloys were examined in terms of the magnetic properties, structure and transition temperatures. Depending on the boron concentration single or two phase alloys microstructures were observed. Additionally, the martensitic transformation temperatures decreases with the boron addition. Magnetic-field induced transformation occurs for the alloys with the boron addition up to 0.1 at.%. For alloys with 0.5 and 1.0 at.% of B transformation is hindered

Stability of External α-Al2O3 Scales on Alloy 602 CA at 1100–1200 °C

An external ultrathin α-Al2O3 scale grown on the Ni-base alloy 602 CA during air oxidation at 800 °C was characterized by means of high-resolution TEM/EDX and electron diffraction. Alloy samples pre-oxidized at 800 °C were subsequently exposed at 1100, 1150 and 1200 °C for up to 100 h. Whereas the external alumina remained stable at 1100 °C, with the increasing exposure temperature, the pre-grown alumina scale tended to break down resulting in an external chromia scale accompanied by internal alumina precipitation. The transition from external to internal Al oxidation was investigated using SEM/EDX/EBSD. The critical Al depletion at the scale-alloy interface during the post-exposure at 1100–1200 °C was modeled using the CALPHAD-based thermodynamic-kinetic approach

Ultrastructural analysis of apoptosis and autophagy in the midgut epithelium of Piscicola geometra

Cell death in the endodermal region of the digestive tract of the blood-feeding leech Piscicola geometra was analyzed using light and transmission electron microscopes and the fluorescence method. Sexually mature specimens of P. geometra were bred under laboratory conditions and fed on Danio rerio. After copulation, the specimens laid cocoons. The material for our studies were non-feeding juveniles collected just after hatching, non-feeding adult specimens, and leeches that had been fed with fish blood (D. rerio) only once ad libitum. The fed leeches were prepared for our studies during feeding and after 1, 3, 7, and 14 days (not sexually mature specimens) and some weeks after feeding (the sexually mature). Autophagy in all regions of the endodermal part of the digestive system, including the esophagus, the crop, the posterior crop caecum (PCC), and the intestine was observed in the adult non-feeding and feeding specimens. In fed specimens, autophagy occurred at very high levels—in 80 to 90 % of epithelial cells in all four regions. In contrast, in adult specimens that did not feed, this process occurred at much lower levels—about 10 % (esophagus and intestine) and about 30 % (crop and PCC) of the midgut epithelial cells. Apoptosis occurred in the feeding adult specimens but only in the crop and PCC. However, it was absent in the non-feeding adult specimens and the specimens that were collected during feeding. Moreover, neither autophagy nor apoptosis were observed in the juvenile, non-feeding specimens. The appearance of autophagy and apoptosis was connected with feeding on toxic blood. We concluded that autophagy played the role of a survival factor and was involved in the protection of the epithelium against the products of blood digestion. Quantitative analysis was prepared to determine the number of autophagic and apoptotic cells

The synthesis of deuteriated tri-tert-butyl phosphine

The synthesis of deuteriated tri‐tert‐butyl phosphine is reported. This synthesis is an adaptation of the known procedure for tri‐tert‐butyl phosphine via a Grignard intermediate

Unique features of myogenesis in Egyptian cobra (Naja haje) (Squamata: Serpentes: Elapidae)

During early stages of myotomal myogenesis, the myotome of Egyptian cobra (Naja haje) is composed of homogenous populations of mononucleated primary myotubes. At later developmental phase, primary myotubes are accompanied by closely adhering mononucleated cells. Based on localization and morphology, we assume that mononucleated cells share features with satellite cells involved in muscle growth. An indirect morphological evidence of the fusion of mononucleated cells with myotubes is the presence of numerous vesicles in the subsarcolemmal region of myotubes adjacent to mononucleated cell. As differentiation proceeded, secondary muscle fibres appeared with considerably smaller diameter as compared to primary muscle fibre. Studies on N. haje myotomal myogenesis revealed some unique features of muscle differentiation. TEM analysis showed in the N. haje myotomes two classes of muscle fibres. The first class was characterized by typical for fast muscle fibres regular distribution of myofibrils which fill the whole volume of muscle fibre sarcoplasm. White muscle fibres in studied species were a prominent group of muscles in the myotome. The second class showed tightly paced myofibrils surrounding the centrally located nucleus accompanied by numerous vesicles of different diameter. The sarcoplasm of these cells was characterized by numerous lipid droplets. Based on morphological features, we believe that muscle capable of lipid storage belong to slow muscle fibres and the presence of lipid droplets in the sarcoplasm of these muscles during myogenesis might be a crucial adaptive mechanisms for subsequent hibernation in adults. This phenomenon was, for the first time, described in studies on N. haje myogenesis