Superconductivity in the High-Entropy Ceramics Ti0.2 Zr0.2 Nb0.2 Mo0.2 Ta0.2 Cx with Possible Nontrivial Band Topology

Topological superconductors have drawn significant interest from the scientific community due to the accompanying Majorana fermions. Here, the discovery of electronic structure and superconductivity (SC) in high-entropy ceramics Ti0.2 Zr0.2 Nb0.2 Mo0.2 Ta0.2 Cx (x = 1 and 0.8) combined with experiments and first-principles calculations is reported. The Ti0.2 Zr0.2 Nb0.2 Mo0.2 Ta0.2 Cx high-entropy ceramics show bulk type-II SC with Tc ≈ 4.00 K (x = 1) and 2.65 K (x = 0.8), respectively. The specific heat jump (∆C/γTc ) is equal to 1.45 (x = 1) and 1.52 (x = 0.8), close to the expected value of 1.43 for the BCS superconductor in the weak coupling limit. The high-pressure resistance measurements show a robust SC against high physical pressure in Ti0.2 Zr0.2 Nb0.2 Mo0.2 Ta0.2 C, with a slight Tc variation of 0.3 K within 82.5 GPa. Furthermore, the first-principles calculations indicate that the Dirac-like point exists in the electronic band structures of Ti0.2 Zr0.2 Nb0.2 Mo0.2 Ta0.2 C, which is potentially a topological superconductor. The Dirac-like point is mainly contributed by the d orbitals of transition metals M and the p orbitals of C. The high-entropy ceramics provide an excellent platform for the fabrication of novel quantum devices, and the study may spark significant future physics investigations in this intriguing material.

[Study on promoting bone formation in osteoporotic zebrafish by lithium-doped hydroxyapatite nanowires]

PURPOSE

To observe the regulatory effect of lithium-doped hydroxyapatite nanowires on bone metabolism in osteoporotic zebrafish induced by dexamethasone.

METHODS

Pure hydroxyapatite nanowires(nHA) and hydroxyapatite nanowires doped with 10% lithium ions (Li-nHA) were prepared by using hydrothermal method, and then material characterization was performed. The juvenile zebrafish cultured for 3 days(3dpf) were selected and co-cultured with nHA and Li-nHA extracts up to 7dpf. A negative(0.1% DMSO) control group was set up and transgenic zebrafish Tg(ola.sp7:nlsGFP) was used to select the best concentration for promoting bone formation. The osteoporotic zebrafish were induced by dexamethasone and incubated with nHA and Li-nHA extracts. The wild-type zebrafish was stained with alizarin red and the osteogenic differentiation was observed in transgenic zebrafish. Real-time quantitative PCR was adopted to detect osteogenic maker genes, such as zinc finger transcription factor (SP7), alkaline phosphatase (ALP), osteoprotegerin (OPG), Runt related transcription factor 2(Runx2) and osteocalcin (OCN). Statistical analysis was performed with GraphPad Prism 9.3 software.

RESULTS

nHA and Li-nHA promoted bone formation and up-regulated expression levels of ALP, OCN, Runx2, SP7 and OPG of osteoporotic zebrafish. Compared with nHA, Li-nHA significantly increased the mineralization specific staining area and cumulative optical density of zebrafish bone, and the expression of osteogenic maker genes was also significantly increased.

CONCLUSIONS

Doping lithium ions in nano hydroxyapatite can enhance its osteoinductive properties, and Li-nHA can effectively improve bone formation of osteoporotic zebrafish.

Senolytic Treatment Improve Small Intestine Regeneration in Aging

Aging induces a series of alterations, specifically a decline in the stature and number of villi and crypts in the small intestine, thus compromising the absorbent capability of the villi. This investigation employed a senolytic combination of dasatinib and quercetin (D+Q) to examine its impact on the intestinal tract of elderly mice. Our findings demonstrate that D+Q treatment leads to a decrease in the expression of p21, p16, and Ki67, while concurrently triggering removal of apoptotic cells within the villi. Additionally, D+Q treatment exhibits the ability to promote growth in both the height and quantity of villi and crypts, along with stimulating nitric oxide (NO) production in aged mice. The study presented a model to assess strategies to alleviate age-related senescence in the intestinal tract of elderly mice. Importantly, D+Q showcases promising potential in enhancing intestinal functionality within the aging.

Low-intensity pulsed ultrasound promotes angiogenesis via the AKT pathway and DNA methylation in human umbilical vein endothelial cells

Angiogenesis involves the activation of endothelial cells (ECs). Low-intensity pulsed ultrasound (LIPUS), which delivers ultrasound waves at a low intensity, can induce the angiogenic potential of ECs. However, the underlying cellular mechanisms remain to be elucidated. In this study, the LIPUS parameters were 1.5 MHz pulsed frequency, 200 us pulse duration, 1.0 kHz repetition rate, and 30 mW/cm² energy intensity. First, we evaluated the effects of LIPUS on the proliferation and angiogenic differentiation of the EC line EA.hy926. The results showed that LIPUS could induce cell proliferation, promote migration, and increase mRNA level inKDR and CD144.Also, the mRNA level and secretion of VEGF were enhanced. We then investigated the role of the AKT signaling pathway in this process. We observed that the expression of p-AKT was upregulated which means that the AKT signaling pathway could be activated by LIPUS, while inhibitor LY294002 of the AKT signaling pathway effectively blocked LIPUS-induced angiogenesis. Finally,we applied confocal Raman microscopy to track biomolecular changes in cells after LIPUS treatment. Spectral analysis showed DNA methylation changes. An Infinium Methylation assay suggested that399 sites were significantly different. After KEGG enrichment analysis, we found seven genes (IRS1, GNG7, COL4A1, FOXO3, COL4A2, CDK4 and EGF) which were closely related to AKT signaling pathway. We verified that AKT signaling pathway inhibition partially blocked LIPUS-induced DNA methylation changes. Ourstudy demonstrated that LIPUS couldpromote the proliferation and angiogenic differentiation of ECs via the AKT signaling pathway. LIPUS could also alter DNA methylation of ECs via the activation of AKT signal.

Synthesis of new plant growth regulator: N-(fatty acid) O-aryloxyacetyl ethanolamine

N-(fatty acyl) O-aryloxyacetyl ethanolamines, prepared from N-acylethanolamine (NAE) and aryloxyacetic acid, were tested for plant growth regulating activity. Compared with N-stearoylethanolamine, most compounds exhibit improved plant growth stimulating activity. In particular, those with chlorine on aryl ring show better activity than 2,4-dichlorophenyloxyacetic acid in stimulating hypocotyls elongation of rape which indicates that chlorine on aryl ring appears significant. Moreover, these derivatives display improved solubility.

Tissue factors on acute promyelocytic leukemia and endothelial cells are differently regulated by retinoic acid, arsenic trioxide and chemotherapeutic agents

The aberrant expression of tissue factor (TF) in acute promyelocytic leukemia (APL) cells has been implicated in the pathogenesis of the APL coagulopathy. In this study, we found that in APL patients receiving ATRA or As2O3 treatment, the improvement in hypercoagulobility and hyperfibrinolysis paralleled the correction of plasma fibrinogen level and amelioration of bleeding symptoms. Notably, clinical improvement was also correlated to ATRA/As2O3-induced rapid decrease of membrane procoagulant activity (PCA) and TF contents of APL blasts. Consistent with the in vivo findings, the membrane PCA, TF antigen and its mRNA level within NB4 cells were rapidly down-regulated by 1 microM ATRA or As2O3, while 0.2 microg/ml DNR increased these TF parameters prior to its effect upon apoptosis induction. The down-regulation of TF mRNA by ATRA was partially de novo protein synthesis-dependent and at least partially attributed to a mechanism of destabilizing TF mRNA. On the other hand, in addition to its modulation on mRNA, As2O3 could also induce an accelerated TF protein turnover. These distinct effects were corroborated with the properties of these agents in causing the degradation of PML-RARalpha protein. All three therapeutic agents, however, enhanced the potential of NB4 cells to stimulate the expression of TF and PCA in endothelium. Taken together, our data suggest that the rapid and distinct regulation of TF on APL cells by these therapeutic agents might at least partially contribute to their effects on APL coagulopathy.

Distinct leukemia phenotypes in transgenic mice and different corepressor interactions generated by promyelocytic leukemia variant fusion genes PLZF-RARalpha and NPM-RARalpha

Acute promyelocytic leukemia (APL) is characterized by a specific chromosome translocation involving RARalpha and one of four fusion partners: PML, PLZF, NPM, and NuMA genes. To study the leukemogenic potential of the fusion genes in vivo, we generated transgenic mice with PLZF-RARalpha and NPM-RARalpha. PLZF-RARalpha transgenic animals developed chronic myeloid leukemia-like phenotypes at an early stage of life (within 3 months in five of six mice), whereas three NPM-RARalpha transgenic mice showed a spectrum of phenotypes from typical APL to chronic myeloid leukemia relatively late in life (from 12 to 15 months). In contrast to bone marrow cells from PLZF-RARalpha transgenic mice, those from NPM-RARalpha transgenic mice could be induced to differentiate by all-trans-retinoic acid (ATRA). We also studied RARE binding properties and interactions between nuclear corepressor SMRT and various fusion proteins in response to ATRA. Dissociation of SMRT from different receptors was observed at ATRA concentrations of 0.01 microM, 0.1 microM, and 1.0 microM for RARalpha-RXRalpha, NPM-RARalpha, and PML-RARalpha, respectively, but not observed for PLZF-RARalpha even in the presence of 10 microM ATRA. We also determined the expression of the tissue factor gene in transgenic mice, which was detected only in bone marrow cells of mice expressing the fusion genes. These data clearly establish the leukemogenic role of PLZF-RARalpha and NPM-RARalpha and the importance of fusion receptor/corepressor interactions in the pathogenesis as well as in determining different clinical phenotypes of APL.