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Abstract: As-quenched and nanocrystalline HITPERM-type (Fe1−x Co x )86Hf7B6Cu1 alloys were investigated by conventional Mössbauer spectroscopy. The spectrum of as-quenched alloy presents a typical broadened and overlapped sextet, which confirms that the as-quenched alloy in fully amorphous state. After nanocrystallization, each spectrum of the alloys studied consists of three components: crystalline phase, interface and residual amorphous matrix except x =0.8 alloy. Co addition increases the hyperfine field and the maximum value exhibits in the x =0.2 alloy. The Fe concentration in bcc-FeCo crystals and the fraction of crystalline phase influenced by Co addition are opposite. The forming of boride phases after prolonged annealing decline the soft magnetic properties of the alloy studied. [Copyright &y& Elsevier]

Abstract: The relationship between coercivity and structure in nanocrystalline (Fe1− x Co x )86Hf7B6Cu1 () alloys was surveyed. It was found that the increase of Co content in the alloys studied was accompanied by the increase of coercivity. However, we suggest that the factors influencing the coercivity change with the concentration of cobalt in these nanocrystalline alloys. In the iron-rich alloys, the average grain size and magnetostriction play predominant roles in the coercivity. On the other hand, in the case of cobalt-rich alloys, the coercivity mostly originates from the FCC-Co phase with large magnetocrystalline anisotropy and the weak exchange coupling between BCC-Fe(Co) and FCC-Co(Fe). [Copyright &y& Elsevier]

Abstract: Temperature evolution of the coercivity of nanocrystalline samples of Fe60Co18Nb6B15Cu1 alloy with different crystalline fractions was measured from room temperature up to 690K. Although room temperature coercivity increases as the nanocrystallization progresses, the thermal stability of the magnetic properties of the system is clearly enhanced as the crystalline volume fraction increases. Microstructure was characterized using room temperature Mössbauer spectra which can be interpreted on the basis of the presence of three different regions: amorphous, crystalline and interface. [Copyright &y& Elsevier]

A new family of Fe–Co based high temperature nanocrystalline alloy was developed using Fe85-xCoxNb5B8P2 as a precursor amorphous material, which can be cast in air. The nanocrystalline sample presented a flat hysteresis loop with excellent high frequency and high temperature behaviour. The material crystallizes at relative low temperature (400°C), with a relatively low activation energy (2.7 eV) for x=20. The sample annealed at 500°C shows temperature independent soft magnetic properties (Hc around 40 A/m, relative permeability 450 up to 1 MHz) up to the applied annealing temperature. [Copyright &y& Elsevier]

Fe81P1Si23Nb3Cu1 metallic glass is used as the parent alloy for a new soft magnetic nanocrystalline material. Two structural transformations of the as-cast alloy are identified during the annealing process. The microstructures created are related to magnetic properties of the nanocrystalline samples. [Copyright &y& Elsevier]

Nutritional and metabolic cues are integral to animal development. Organisms use them both as sustenance and environmental indicators, fueling, informing and influencing developmental decisions. Classical examples, such as the Warburg effect, clearly illustrate how genetic programs control metabolic changes. However, the way that nutrition and metabolism can also modulate or drive genetic programs to instruct developmental trajectories is much more elusive, owing to several difficulties including uncoupling permissive and instructive functions. Here, we discuss recent advancements in the field that highlight the developmental role of nutritional and metabolic cues across multiple levels of organismal complexity., (© 2023. Published by The Company of Biologists Ltd.)

The molecular mechanisms that maintain cellular identities and prevent dedifferentiation or transdifferentiation remain mysterious. However, both processes are transiently used during animal regeneration. Therefore, organisms that regenerate their organs, appendages, or even their whole body offer a fruitful paradigm to investigate the regulation of cell fate stability. Here, we used Hydra as a model system and show that Zic4, whose expression is controlled by Wnt3/β-catenin signaling and the Sp5 transcription factor, plays a key role in tentacle formation and tentacle maintenance. Reducing Zic4 expression suffices to induce transdifferentiation of tentacle epithelial cells into foot epithelial cells. This switch requires the reentry of tentacle battery cells into the cell cycle without cell division and is accompanied by degeneration of nematocytes embedded in these cells. These results indicate that maintenance of cell fate by a Wnt-controlled mechanism is a key process both during homeostasis and during regeneration.

Cells of the freshwater cnidarian Hydra possess an exceptional regeneration ability. In small groups of these cells, organizer centers emerge spontaneously and instruct the patterning of the surrounding population into a new animal. This property makes them an excellent model system to study the general rules of self-organization. A small tissue fragment or a clump of randomly aggregated cells can form a hollow spheroid that is able to establish a body axis de novo. Interestingly, mechanical oscillations (inflation/deflation cycles of the spheroid) driven by osmosis accompany the successful establishment of axial polarity. Here we describe different approaches for generating Hydra tissue spheroids, along with imaging and image analysis techniques to investigate their mechanical behavior., (© 2022. The Author(s).)

Mechanical input shapes cell fate decisions during development and regeneration in many systems, yet the mechanisms of this cross-talk are often unclear. In regenerating Hydra tissue spheroids, periodic osmotically driven inflation and deflation cycles generate mechanical stimuli in the form of tissue stretching. Here, we demonstrate that tissue stretching during inflation is important for the appearance of the head organizer—a group of cells that secrete the Wnt3 ligand. Exploiting time series RNA expression profiles, we identify the up-regulation of Wnt signaling as a key readout of the mechanical input. In this system, the levels of Wnt3 expression correspond to the levels of stretching, and Wnt3 overexpression alone enables successful regeneration in the absence of mechanical stimulation. Our findings enable the incorporation of mechanical signals in the framework of Hydra patterning and highlight the broad significance of mechanochemical feedback loops for patterning epithelial lumens.

The aim of the present work was to investigate an influence of W addition on the phase constitution, microstructure and magnetic properties of the Pr 9 Fe 65 W x B 26-x (where: x = 2, 4, 6, 8) alloy ribbons. Ribbons were obtained using the melt-spinning technique under low pressure of Ar. The as-cast samples were fully amorphous and revealed soft magnetic properties. These facts were confirmed by X-ray diffractometry, Mössbauer spectroscopy and magnetic measurements. Differential scanning calorimetry and differential thermal analysis allowed us to determine the thermal stability parameters of the amorphous phase. The Kissinger plots were constructed in order to calculate the activation energies for crystallization. Heat treatment carried out at various temperatures caused changes in the phase constitution and magnetic properties of the alloys. The phase analysis has shown the presence of the hard magnetic Pr 2 Fe 14 B and paramagnetic Pr 1+x Fe 4 B 4 phases. Additionally, for the x = 2 and x = 6 alloys, a crystallization of soft magnetic Fe 2 B and α-Fe phases was observed. The Mössbauer spectroscopy allowed us to determine the volume fractions of constituent phases formed during annealing. The microstructure of annealed ribbons was observed using transmission electron microscopy.

As future scientists, university students need to learn how to avoid making errors in their own manuscripts, as well as how to identify flaws in papers published by their peers. Here we describe a novel approach on how to promote students' ability to critically evaluate scientific articles. The exercise is based on instructing teams of students to write intentionally flawed manuscripts describing the results of simple experiments. The teams are supervised by instructors advising the students during manuscript writing, choosing the 'appropriate' errors, monitoring the identification of errors made by the other team and evaluating the strength of their arguments in support of the identified errors. We have compared the effectiveness of the method with a journal club-type seminar. Based on the results of our assessment we propose that the described seminar may effectively complement the existing approaches to teach critical scientific thinking. © 2017 by The International Union of Biochemistry and Molecular Biology, 46(1):22-30, 2018., (© 2017 The International Union of Biochemistry and Molecular Biology.)