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Spermatogonial stem cells (SSCs) are the most primitive cells in spermatogenesis and are the only adult stem cells capable of passing on the genome of a given species to the next generation. SSCs are the only adult stem cells known to exhibit high Oct4 expression and can be induced to self-reprogram into luripotent cells depending on culture conditions. Epigenetic modulation is well known to be involved in the induction of pluripotency of somatic cells. However, epigenetic modulation in selfreprogramming of SSCs into pluripotent cells has not been studied.In this study, we examined the involvement of epigenetic modulation by assessing whether selfreprogramming of SSCs is enhanced by treatment with epigenetic modulators. We found that secondgeneration selective class I HDAC inhibitors increased SSC reprogramming efficiency, whereas nonselective HDAC inhibitors had no effect.We showed that pluripotent stem cells derived from adult SSCs by treatment with small molecules with epigenetic modulator functions exhibit pluripotency

Process optimization of additively manufactured Ti–6Al–4V alloy is an important aspect of the production of engineered, high-performance parts for the aerospace and medical industries. In this study, the microstructural evolution and mechanical properties of direct energy deposition processed Ti–6Al–4V alloy were investigated using different processing parameters. Experimental analyses revealed that the line energy density corresponding to the processing parameters of the direct energy deposition process influences the properties of additively manufactured Ti–6Al–4V alloy. First, an optimal line energy density limits the incidence and size of voids resulting from a lack of fusion to enhance both alloy strength and ductility. Second, an excessively high energy density induces the coarsening of prior-β grains to impair both alloy strength with the Hall–Petch relationship and alloy ductility due to the plastic deformation instability caused by the limited number of grains. These results indicate that both the extent of fusion and prior-β grain size affect the mechanical properties of additively manufactured Ti–6Al–4V alloy. Moreover, the results demonstrate the utility of the line energy density-based approach in determining the optimal processing parameters for realizing high-performance materials.

Umbilical cord blood (UCB) is an alternative source of allogeneic hematopoietic stem cells (HSCs) for transplantation to treat various hematological disorders. The major limitation to the use of UCB-derived HSCs (UCB-HSCs) in transplantation, however, is the low numbers of HSCs in a unit of cord blood. To overcome this limitation, various cytokines or small molecules have been used to expand UCB-HSCs ex vivo. In this study, we investigated a synergistic effect of the combination of HIL-6, SR1, and UM171 on UCB-HSC culture and found that this combination resulted in the highest number of CD34

Background and Objectives Genomic imprinting modulates growth and development in mammals and is associated with genetic disorders. Although uniparental embryonic stem cells have been used to study genomic imprinting, there is an ethical issue associated with the destruction of human embryos. In this study, to investigate the genomic imprinting status in human neurodevelopment, we used human uniparental induced pluripotent stem cells (iPSCs) that possessed only maternal alleles and differentiated into neural cell lineages. Methods Human somatic iPSCs (hSiPSCs) and human parthenogenetic iPSCs (hPgiPSCs) were differentiated into neural stem cells (NSCs) and named hSi-NSCs and hPgi-NSCs respectively. DNA methylation and gene expression of imprinted genes related neurodevelopment was analyzed during reprogramming and neural lineage differentiation. Results The DNA methylation and expression of imprinted genes were altered or maintained after differentiation into NSCs. The imprinting status in NSCs were maintained after terminal differentiation into neurons and astrocytes. In contrast, gene expression was differentially presented in a cell type-specific manner. Conclusions This study suggests that genomic imprinting should be determined in each neural cell type because the genomic imprinting status can differ in a cell type-specific manner. In addition, the in vitro model established in this study would be useful for verifying the epigenetic alteration of imprinted genes which can be differentially changed during neurodevelopment in human and for screening novel imprinted genes related to neurodevelopment. Moreover, the confirmed genomic imprinting status could be used to find out an abnormal genomic imprinting status of imprinted genes related with neurogenetic disorders according to uniparental genotypes.

OCT4 and NANOG are core transcription factor genes in self-renewal, differentiation, and reprogramming. Here, we generated an OCT4-EGFP, NANOG-tdTomato dual reporter hiPSC line, KKUi001-A, on the basis of human induced pluripotent stem cells using CRISPR/Cas9 technology. EGFP and tdTomato reporter were inserted into before the stop codon of OCT4 and NANOG, respectively. Simultaneous expression of EGFP and tdTomato was observed when expression of OCT4 and NANOG was changed during differentiation and reprogramming. KKUi001-A hiPSC line will be a useful tool to find initial time point of OCT4 and NANOG expression during reprogramming process and to screen small molecules that promote reprogramming.

Animal models and human studies showed that in utero cigarette smoke exposure decreases sperm counts of offspring. This study used a mouse model to investigate the effects of maternal exposure to cigarette smoke on reproductive systems in F1 and F2 male offspring. Female ICR mice were exposed either to clean air or to cigarette smoke during pregnancy at the post-implantation stage. Epididymal sperm counts were decreased in a cigarette smoke dose-dependent manner in F1 (by 40-60%) and F2 males (by 23-40%) at postnatal day 56. In F1, the seminiferous epithelium heights were lower in the cigarette smoke-exposed groups than in the control group, and these effects were sustained in F2 males. Results suggest that maternal cigarette smoke exposure during pregnancy can have a multigenerational adverse effect on sperm counts in male offspring, which is mediated through in utero exposure of fetal germ cells to cigarette smoke.

Rapid melting and solidification cycles during laser-based additive manufacturing create non-equilibrium microstructures in stainless steels (SSs) including atomic segregation-mediated ultrafine δ-ferrite, in contrast to coarse δ-ferrite in typical casting-produced SSs. The formation of metastable ultrafine δ-ferrite in additively manufactured SSs generates a new coherent interface in austenitic matrix. However, currently a consensus on how ultrafine δ-ferrite interacts with dislocations is lacking, particularly in directed energy deposition-processed 304L SS. Herein, the role of ultrafine δ-ferrite on the mechanical properties of directed energy deposition-processed 304L SS was investigated by modifying the laser scan speeds of 850 and 1150 mm/min and by performing electron microscopy-based characterization. We find that the ultrafine δ-ferrite maintains coherency with a γ-austenite matrix in the undeformed state and interacts with dislocations during plastic deformation. Additionally, the twin volume fraction depends on the initial grain size of 304L SSs, which results in a 23 MPa (for strength) and 5% (for ductility) mechanical property difference between the 850 (SLOW) and 1150 (FAST) mm/min scan speed conditions. Through the synergetic effects of ultrafine δ-ferrite, deformation-induced twins and twin intersections, the present additively manufactured 304L SS achieves an outstanding ductility that is larger than that of the previous directed energy deposition-processed SSs. This result proves that the ultrafine metastable phase contributes to the prolonged plasticity of the additively manufactured metallic alloys if the metastable phase maintains coherency with the matrix during plastic deformation.

Spermatogonial stem cells (SSCs) are unipotent adult stem cells, capable of differentiating into sperm cells. SSCs can be cultured in vitro for a long time. SSCs expressing Oct4, a pluripotency marker, and are the only adult cells which pluripotency can be induced under defined culture conditions. However, because 2D culture imposes limitations in cell junction formation, cell shape, metabolism, response to stimuli, and cell interface with medium, mechanistic studies on reprogramming of SSCs using feeder cells still have many challenges. Recent studies have shown that a culture system using a bio-matrix can be used in long-term feeder-free SSCs culture and for induction of pluripotency in SSCs. However, the bio-matrix cannot be the optimal micro-environment in mechanistic studies because it creates a physical barrier to growth factors and other signaling molecules. To overcome this effect of the matrix, we reprogrammed SSCs into pluripotent ESC-like cells, so-called germline-derived pluripotent stem cells (gPSCs) by using a 3D scaffold, in which cells are less responsive to external stimuli than in 2D cultures. Thus, we confirm the possibility of SSC reprogramming in the spheroidal state and suggest the utility of 3D scaffolds as a tool for studying the mechanism of SSC reprogramming into gPSCs without a bio-matrix.

Recently, efforts have been made to enhance educational competency based on Computational Thinking (CT) in relation to informatics education at home and abroad. Although many informatics teachers training programs are steadily operated in order to cultivate the education capacity in response to the changing demands of the times, this is done without acceptance of an opinion process of informatics teachers’ educational needs. Therefore, this study analyzed recognition and educational needs based on the competency model developed for the informatics teachers in secondary school. Educational needs were analyzed using Borich’s needs formula. The results of the study are as follows: First, the average of Required Competency Level (RCL) of each competency-unit was higher than average of Present Competency Level (PCL) and there were statistically significant differences between RCL and PCL. Secondly, the educational need of each competency-unit was highest in ‘Informatics Teaching and Learning Strategy Establishment and Operation’. Thirdly, the educational needs of Knowledge domain showed the highest educational needs in the competencies of the ‘Informatics Teaching and Learning Strategy Establishment and Operation’ obtaining more than 7 points. Finally, the educational needs of Skill domain took the 1st to 3rd priorities and indicated higher in the competencies of the same competency-unit as Knowledge domain.