Instantons in supersymmetric theories

Instanton effects are considered for a sample of supersymmetric theories, namely, quantum mechanics, gluodynamics, Higgs model. The problem is how to reconcile the apparent lack of the boson-fermion symmetry in the effective instanton induced interactions with supersymmetry of the corresponding lagrangians. It is shown that in the case of quantum mechanics and the Higgs model there is actually no conflict between supersymmetry and the instanton calculus since the Ward identities, associated with the supersymmetry transformations, are satisfied. In quantum mechanics this is due to spontaneous symmetry breaking, or pole terms in matrix elements of supercharge, while in the case of the supersymmetric Higgs model the effective fermion interaction just reduces to a total derivative. In the case of supersymmetric gluodynamics, however, the standard instanton calculus explicitly violates naive Ward identities.     

Processed Tissue–Derived Extracellular Matrices: Tailored Platforms Empowering Diverse Therapeutic Applications

Tissue‐derived decellularized extracellular matrices (dECM) have gradually become the gold standard of scaffolds for tissue engineering, owing to their close mirroring of the intricate composition, architecture, and topology of the native extracellular matrix (ECM). Intriguingly, further manipulation of these acellular tissues through various processing techniques has been demonstrated to be an effective strategy to control their characteristics and impart them with ample valuable new traits, thereby expanding their applicability to a significantly wider spectrum of research and translational applications. Herein, state‐of‐the‐art processed dECM platforms and their potential applications are focused on. The ECM characteristics that make it so appealing for tissue engineering are presented, followed by a concise discussion on the main considerations for choosing a dECM source for such applications. The key methodologies for dECM processing, including hydrogel production, bioprinting, electrospinning, and production of porous scaffolds, microcarriers, and microcapsules, as well as their inherent advantages and challenges, are introduced. To demonstrate the use of processed dECM platforms for tissue engineering, selected in vivo and in vitro applications recently developed utilizing these platforms are highlighted. Finally, concluding remarks and a prospective outlook for future developments and improvements in the field of processed dECM‐based devices are given.     

Mn2+ alters peroxidase profiles and lignin degradation by the white-rot fungus Pleurotus ostreatus under different nutritional and growth conditions

The white-rot fungus Pleurotus ostreatus produces two types of extracellular peroxidases: manganese-dependent peroxidase (MnP) and versatile peroxidase (VP). The effect of Mn²⁺ on fungal growth, peroxidase activity profiles, and lignin degradation by P. ostreatus was studied in liquid culture and under solid-state fermentation conditions on perlite, the latter resembling the natural growth conditions of this fungus. The fungus was grown in either a defined asparagine-containing basidiomycete selective medium (BSM) or in a rich peptone medium (PM). Biomass production, as determined by respiration experiments in solid-state fermentation and liquid cultures and fungal growth on Petri dishes, was higher in the PM than in the BSM. Mn²⁺ affected biomass production only in the PM on Petri dishes. In the nonamended PM, high levels of MnP and VP activity were detected relative to the nonamended BSM. Nevertheless, a higher rate of ¹⁴C-lignin mineralization was measured in the Mn²⁺-amended BSM, as determined during the course of 47 d of fermentation. Mn²⁺ amendment of the PM increased mineralization rate to that obtained in the Mn²⁺-amended BSM. The enzyme activity profiles of MnP and VP were studied in the BSM using anion-exchange chromatography. In the nonamended BSM, only minute levels of MnP and VP were detected. On Mn²⁺ amendment, two MnP isoenzymes (B1 and B2) appeared. Isoenzyme B2 was purified and showed 100% identity with the MnP isoenzyme purified in our previous study from PM-solid-state fermentation (P6). P6 was found to be the dominant isoenzyme in terms of activity level and gene expression compared with the VP isoenzymes. Based on these results, we concluded that Mn²⁺ plays a key role in lignin degradation under different nutritional and growth conditions, since it is required for the production of MnP in P. ostreatus.     

From eilatin to isoeilatin: a skeletal rearrangement strongly influences pi-stacking of Ru(II) complex

The C(1)-symmetrical complex [Ru(bpy)(2)(ieil)][PF(6)](2) exhibits unique electrochemical and photophysical properties, and forms discrete dimers in solution and in the solid state held by weak pi-pi stacking interactions via its isoeilatin ligand, preferentially from one of its faces and in a specific orientation.