Timber structures are susceptible to moisture, contamination, and pest infestation, which can compromise their integrity and pose a significant fire hazard. Despite these drawbacks, timber's lightweight properties, eco-friendliness, and alignment with current architectural trends emphasizing sustainability make it an attractive option for construction. Moreover, timber structures offer economic benefits and provide a natural aesthetic that regulates building temperature and humidity. In recent years, timber domes have gained popularity due to their high recyclability, lightness, and improved fire resistance. Researchers are exploring hybrid timber and steel domes to enhance stability and rigidity. However, shallow dome structures still face challenges related to structural instability. This study investigates stability problems associated with timber domes, the behavior of timber and steel hybrid domes, and the impact of timber member positioning on dome stability and critical load levels. The paper analyzes unstable buckling in single-layer lattice domes using an incremental analysis method. The critical buckling load of the domes is examined based on the arrangement of timber members in the inclined and horizontal directions. The analysis shows that nodal snapping is observed in the case of a concentrated load, whereas snap-back is also observed in the case of a uniform load. Furthermore, the use of inclined timber and horizontal steel members in the lattice dome design provides adequate stability.

Recent genomic evidences from unfractionated embryonic stem cell (ESC) cultures have demonstrated high levels of concomitant activating (H3K4me3) and repressive (H3K27me3) histone methylations, termed “bivalent marks”, at lineage specific gene loci, demonstrating that all cells residing within the cultures are developmentally equipotent. However, this dogma has been challenged, indicating that ESC cultures are heterogeneous, with individual cells displaying dynamic metastability and failed to make a connection with the variations between cell lines, a broad spectrum of differentiation, continuous phenotypic oscillation, and the expression of lineage specific genes in undifferentiated state. Recently, functional in vitro assays via fractionation of ESC cultures based on comparable expression of some phenotypes (c‐KIT, A2B5, SSEA3, Nanog, Rex‐1, IGFR1, and Stella) revealed a plastic gradient of clonogenicity and lineage specification within ESC cultures reflected by the presence of bivalent marks, which are resolved down to activating “monovalent marks”. More interestingly, dynamic heterogeneity represents a conserved feature on both mouse ESCs and human ESCs as being essentially required for self‐renewal and, more importantly, differentiation. However, it is the most substantive obstacle to control and specify ESCs into desirable cell types. Mostly, differentiation from ESCs has been evaluated by measuring the responses of whole EB populations under the specific inducible conditions, making it difficult to identify, which cell populations are dominantly contributing to differentiated progeny from ESCs. Therefore, further identification of novel transcriptional and phenotypic markers may allow for the isolation and enrichment of more promising target cells for stem cell‐based clinical therapy.

To identify genes implicated in the control of pluripotency as well as characteristics of stem cells, we analyzed expression profiles of genes derived from mouse morulas, blastocysts, embryonic stem cells, mesenchymal stem cells, and uterus tissue cDNA microarray. Comparative analyses of their expression profiles identified putative clones that expressed specifically in specific samples or not in a specific sample. The expression pattern of these candidate clones was analyzed using RT-PCR and non-radioactive in situ hybridization. Functional annotation of these clones on pluripotency and stem cells and molecular mechanisms underlying many facets of mammalian development and differentiation.