Somatic cell nuclear transfer and transcription-factor-based reprogramming revert adult cells to an embryonic state, and yield pluripotent stem cells that can generate all tissues. Through different ...mechanisms and kinetics, these two reprogramming methods reset genomic methylation, an epigenetic modification of DNA that influences gene expression, leading us to hypothesize that the resulting pluripotent stem cells might have different properties. Here we observe that low-passage induced pluripotent stem cells (iPSCs) derived by factor-based reprogramming of adult murine tissues harbour residual DNA methylation signatures characteristic of their somatic tissue of origin, which favours their differentiation along lineages related to the donor cell, while restricting alternative cell fates. Such an 'epigenetic memory' of the donor tissue could be reset by differentiation and serial reprogramming, or by treatment of iPSCs with chromatin-modifying drugs. In contrast, the differentiation and methylation of nuclear-transfer-derived pluripotent stem cells were more similar to classical embryonic stem cells than were iPSCs. Our data indicate that nuclear transfer is more effective at establishing the ground state of pluripotency than factor-based reprogramming, which can leave an epigenetic memory of the tissue of origin that may influence efforts at directed differentiation for applications in disease modelling or treatment.
Ischemic Stroke (IS) is a major disease which greatly threatens human health. Recent studies showed sex-specific outcomes and mechanisms of cerebral ischemic stroke. This study aimed to identify the ...key changes of gene expression between male and female IS in humans.
Gene expression dataset GSE22255, including peripheral blood samples, was downloaded from the Gene Expression Omnibus (GEO) dataset. Differentially Expressed Genes (DEGs) with a LogFC>1, and a P-value <0.05 were screened by BioConductor R package and grouped in female, male and overlap DEGs for further bioinformatic analysis. Gene Ontology (GO) functional annotation, Protein-Protein Interaction (PPI) network, "Molecular Complex Detection" (MCODE) modules, CytoNCA (cytoscape network centrality analysis) essential genes and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway interrelation analysis were performed.
In a total of 54,665 genes, 185 (73 ups and 112 downs) DEGs in the female dataset, 461 DEGs (297 ups and 164 downs) in the male dataset, within which 118 DEGs overlapped (7 similar changes in female and male, 111 opposite changes in female and male) were obtained from the GSE22255 dataset. Female, male and overlapping DEGs enriched for similar cellular components and molecular function. Male DEGs enriched for divergent biological processes from female and overlapping DEGs. Sex-specific and overlapping DEGs were put into the PPI network. Overlapping genes such as IL6, presented opposite changes and were mainly involved in cytokine-cytokine receptor interactions, the TNF-signalling pathway, etc.
The analysis of sex-specific DEGs from GEO human blood samples showed that not only specific but also opposite DEG alterations in the female and male stroke genome wide dataset. The results provided an overview of sex-specific mechanisms, which might provide insight into stroke and its biomarkers and lead to sex-specific prognosis and treatment strategies in future clinical practice.
In this paper, we propose a Fourier-Laguerre spectral method for exterior problems of two-dimensional complex obstacles based on the mapping method. We first use a polar coordinate transformation to ...convert the exterior domains of complex obstacles into the exterior domain of the unit disk. Then we apply the polar coordinate transformation to the exterior problem of an elliptic equation, derive its weak formulation and prove the existence and uniqueness of the weak solution. On this basis, we construct the Fourier-Laguerre spectral Galerkin scheme, describe its numerical implementation and analyze the convergence of the numerical solution under the H1-norm. Numerical results indicate that our spectral Galerkin method is easy to implement and possesses high-order accuracy.
Abstract
In order to study the formation and penetration performance of reactive liner, in this paper, a Ta-Zr alloy is used as the liner material, and large cone angle liner, spherical liner and ...arc-cone liner are simulated and analyzed by using AUTODYN software. The following conclusions are obtained: (1) The EFP formed by large cone angle liner has good flight stability, followed by arc cone liner; (2) The length diameter ratio of spherical shaped charge liner is larger than that of arc cone shaped charge liner; (3) The EFP penetration depth of the arc cone shaped liner is larger, and the EFP incident aperture of the large cone angle shaped liner is larger.
In order to improve the microstructural stability of high Cr/Ni austenitic stainless steels (ASSs) at high temperatures, the present work investigated the effects of minor-alloying elements (Mo, Nb, ...Ti, Ta, and W) on the microstructural evolution and mechanical properties of Fe-25Cr-22Ni (wt%) ASS systematically. The designed alloy ingots were hot-rolled, solid-solutioned at 1423 K for 0.5 h, stabilized at 1173 K for 0.5 h, and then aged at 973 K for different hours. It was found that these minor-alloying elements make different contributions to the microstructural stabilities of alloys. Only a small amount of harmful σ particles exists after 408 h-aging in W/Ta-modified alloys, which indicates W and Ta can improve the microstructural stability effectively. Whereas Ti should be forbidden since it accelerates the phase precipitation of Cr23C6 and σ remarkably. Excessive Mo can also promote the formation of σ phase and the transformation of Cr23C6 to σ during aging. The influences of the precipitated phases on mechanical properties of alloys were then studied. Thermal calculations were also performed to analyze the phase precipitation caused by minor-alloying. The Fe-25Cr-22Ni-0.046C-0.73Mo-0.18Nb-0.34Ta (wt%) exhibits excellent mechanical property due to its higher microstructural stability at 973 K, which has great potential for fuel cladding application.
Glitches correspond to sudden jumps of rotation frequency ( ) and its derivative ( ) of pulsars, the origin of which remains not well understood yet, partly because the jump processes of most ...glitches are not well time-resolved. There are three large glitches of the Crab pulsar, detected in 1989, 1996, and 2017, which were found to have delayed spin-up processes before the normal recovery processes. Here we report two additional glitches of this pulsar that occurred in 2004 and 2011 for which we discovered delayed spin-up processes, and present refined parameters of the largest glitch, which occurred in 2017. The initial rising time of the glitch is determined as <0.48 hr. The two glitches that occurred in 2004 and 2011 had delayed spin-up time scales (τ1) of 1.7 0.8 days and 1.6 0.4 days, respectively. We also carried out a statistical study of these five glitches with observed spin-up processes. We find that the Δ versus relation of these five glitches is similar to those with no detected delayed spin-up process, indicating that they are similar to the others in nature except that they have larger amplitudes. For these five glitches, the amplitudes of the delayed spin-up process ( ) and recovery process (Δ d2), their time scales (τ1, τ2), and permanent changes in spin frequency (Δ p) and total frequency step (Δ g) have positive correlations. From these correlations, we suggest that the delayed spin-up processes are common for all glitches, but are too short and thus difficult to be detected for most glitches.
The sit-to-stand test (STST) has been used to evaluate the exercise tolerance of patients with COPD. However, mutual comparisons to predict poor exercise tolerance have been hindered by the variety ...of STST modes used in previous studies, which also did not consider patients' subjective perceptions of different STST modes. Our aim was to compare the five-repetition sit-to-stand test (5STS) with the 30-second sit-to-stand test (30STS) for predicting poor performance in the six-minute walking test and to evaluate patients' subjective perceptions to determine the optimal mode for clinical practice.
Patients with stable COPD performed 5STS, 30STS and the 6MWT and then evaluated their feelings about the two STST modes by Borg dyspnea score and a questionnaire. Moreover, we collected data through the pulmonary function test, mMRC dyspnea score, COPD assessment test and quadriceps muscle strength (QMS). A receiver operating characteristic curve analysis of the 5STS and 30STS results was used to predict 6-minute walk distance (6MWD) <350 m.
The final analysis included 128 patients. Similar moderate correlations were observed between 6MWT and 5STS (
=-0.508,
<0.001) and between 6MWT and 30STS (
=0.528,
<0.001), and there were similar correlations between QMS and 5STS (
=-0.401,
<0.001) and between QMS and 30STS (
=0.398,
<0.001). The 5STS and 30STS score cutoffs produced sensitivity, specificity and positive and negative predictive values of 76.0%, 62.8%, 56.7% and 80.3% (5STS) and 62.0%, 75.0%, 62.0% and 75.0% (30STS), respectively, for predicting poor 6MWT performance. The 5STS exhibited obvious superiority in terms of the completion rate and the subjective feelings of the participants.
As a primary screening test for predicting poor 6MWD, the 5STS is similar to the 30STS in terms of sensitivity and specificity, but the 5STS has a better patient experience.
Our recent study observed that the expression of ubiquitin D (UBD), a member of ubiquitin-like modifier family, was upregulated in colon cancer parenchymal cells. The present study further ...investigated the clinical signicance of UBD in colon cancer.
Using quantitative PCR, tissue microarray (TMA), western blot analysis and immunohistochemical stain, we evaluated UBD mRNA and protein levels in tumour tissues from patients with colon cancer at different stages and in paired adjacent normal epithelium.
Immunohistochemical detection of UBD on a TMA containing 203 paired specimens showed that increased cytoplasmic UBD was signicantly associated with depth of cancer invasion, lymph node metastasis, distant metastasis, tumour histologic grade, advanced clinical stage and Ki-67 proliferative index. Patients with UBD-positive tumours had a significantly higher disease recurrence rate and poorer survival than patients with UBD-negative tumours after the radical surgery. Stratification analysis according to tumour stage revealed UBD as an independent predictor for tumour recurrence in patients with stage II and III tumours.
UBD may contribute to the progression of colon carcinogenesis and function as a novel prognostic indicator of forecasting recurrence of stage II and III patients after curative operations.
Extraventricular neurocytoma is a rare entity, most frequently occurring in brain parenchyma outside the ventricular system. The purpose of this study was to characterize the MR imaging findings in a ...series of 9 patients with EVN verified by results of pathologic examination. All 9 EVNs were solitary and intracranially located. Eight lesions were well demarcated, and 3 showed intratumoral hemorrhage. The solid parts of 7 tumors were primarily isointense on T1-weighted images and heterogeneously enhanced on T1WI with contrast. Although cerebral EVNs can present a wide spectrum of appearances on MR, the imaging patterns appear to vary according to anatomic location and cellularity. Lesions in frontal or parietal lobes often present as well-demarcated large masses with cystic degeneration, hemorrhage, mild-to-moderate edema, and inhomogeneous enhancement. Moreover, the general isointensity of the solid parts of EVN on T1WI may be of some specificity.
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