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Although different chemistries for the spatio‐temporal localization of molecules and gradients of chemical signals within soft materials are now available, the achievement of spatio‐temporal patterns of mechanical properties in such materials and their characterization remain considerable challenges. This study presents the syntheses of two novel photo‐sensitive and thermoresponsive hydrogel systems, a photo‐stiffening and a photo‐softening hydrogel. Their potential for fabricating soft materials with patterned mechanical properties is then demonstrated by fabricating an actuator whose higher‐order bending properties can be switched on with light, and by encoding mechanical properties for digital information encryption and storage. Microindentation and a custom‐made data analysis software are essential for the characterization of all the materials. From a general perspective, this work opens a route to the fabrication of soft materials with patterned mechanical properties, addressing an important emerging challenge in soft materials science with applications in soft robotics and information encryption and storage. [ABSTRACT FROM AUTHOR]

Intrauterine growth retardation (IUGR) has been linked to the onset of diseases in adulthood, including type 2 diabetes, and has been proposed to result from altered gene regulation patterns due to epigenetic modifications of developmental genes. To determine whether epigenetic modifications may play a role in the development of adult diabetes following IUGR, we used a rodent model of IUGR that expresses lower levels of Pdx1, a pancreatic and duodenal homeobox 1 transcription factor critical for [beta] cell function and development, which develops diabetes in adulthood. We found that expression of Pdx1 was permanently reduced in IUGR [beta] cells and underwent epigenetic modifications throughout development. The fetal IUGR state was characterized by loss of USF-1 binding at the proximal promoter of Pdx1, recruitment of the histone deacetylase 1 (HDAC1) and the corepressor Sin3A, and deacetylation of histones H3 and H4. Following birth, histone 3 lysine 4 (H3K4) was demethylated and histone 3 lysine 9 (H3K9) was methylated. During the neonatal period, these epigenetic changes and the reduction in Pdx1 expression could be reversed by HDAC inhibition. After the onset of diabetes in adulthood, the CpG island in the proximal promoter was methylated, resulting in permanent silencing of the Pdx1 locus. These results provide insight into the development of type 2 diabetes following IUGR and we believe they are the first to describe the ontogeny of chromatin remodeling in vivo from the fetus to the onset of disease in adulthood., Introduction Intrauterine growth retardation (IUGR), a common complication of pregnancy, has been linked to the later development of diseases in adulthood such as type 2 diabetes (1). It has been [...]

This work is concerned with the similarity between the two important reduction schemes: optimal prediction and stochastic averaging. To this end, we consider a randomly perturbed Hamiltonian system and derive a generalized Langevin equation from a Kolmogorov backward equation. We then show the similarity by adopting conditional expectation as our projection operator in the generalized Langevin equation. The characteristics of the conditional expectation play a central role in our study. [DOI: 10.1115/1.2748777]

The purpose of this work is to develop an averaging approach to study the dynamics of a vibro-impact system excited by random perturbations. As a prototype, we consider a noisy single-degree-of-freedom equation with both positive and negative stiffness and achieve a model reduction, i.e., the development of rigorous methods to replace, in some asymptotic regime, a complicated system by a simpler one. To this end, we study the equations as a random perturbation of a two-dimensional weakly dissipative Hamiltonian system with either center type or saddle type fixed points. We achieve the model-reduction through stochastic averaging. Examination of the reduced Markov process on a graph yields mean exit times, probability density functions, and stochastic bifurcations. [DOI: 10.1115/1.2041660]

Femtosecond laser-interference induced amorphization (FLIA) is used for forming a spatially periodic magnetic structure by selectively amorphizing the surface of bulk [Co.sub.2]MnSi. The periodicity of the modulated structure is decreased or the process can be modified to write two-dimensional pattern so that the resulting magnetic structure can be used for a permanent magnetic identification.

Femtosecond laser-interference induced amorphization (FLIA) was used to form a spatially periodic magnetic structure by selectively amorphizing the surface of bulk Co2MnSi. Regularly spaced alternating lines with a periodicity of 2 μm were produced by FLIA. Magnetic force microscopy of the samples clearly revealed one-dimensional periodic magnetic domains resulting from the modulated surface structure which was confirmed by transmission electron microscopy. The periodicity of the modulated structure can be further decreased or the process can be modified to write two-dimensional pattern so that the resulting magnetic structure can be potentially utilized for a permanent magnetic identification. [ABSTRACT FROM AUTHOR]

Abstract: Electrochemical lithiation of Co2MnSi with a Heusler structure is investigated as a candidate negative electrode (anode) material for secondary lithium batteries. The electrode maintains a reversible discharge capacity of 112mAhg−1 for 50 cycles when cycled between 0.01 and 3V. It is proposed that the lithiation mechanism consists of two steps. Co2MnSi transforms to Heusler-type Li2MnSi during the first charge cycle and subsequent charge–discharge cycles involve the formation of a solid solution in Li x MnSi. The latter compound maintains its structural integrity throughout cycling to provide steady cycling behaviour. Magnetic measurements are also employed to substantiate further the structural changes during electrochemical cycling. [Copyright &y& Elsevier]

We propose the regularized recurrent inference machine (rRIM), a novel machine-learning approach to solve the challenging problem of deriving the pairing glue function from measured optical spectra. The rRIM incorporates physical principles into both training and inference and affords noise robustness, flexibility with out-of-distribution data, and reduced data requirements. It effectively obtains reliable pairing glue functions from experimental optical spectra and yields promising solutions for similar inverse problems of the Fredholm integral equation of the first kind., (© 2024. The Author(s).)