162 research outputs found
Observation of zero resistance above 100 K in PbCu(PO)O
Room-temperature superconductivity has always been regarded as the ultimate
goal in the fields of solid-state physics and materials science, with its
realization holding revolutionary significance, capable of triggering
significant changes in energy transmission and storage. However, achieving it
poses various challenges. Recent research revealed that material
PbCu(PO)O displays room-temperature superconductivity
under atmospheric pressure, sparking global interest in further exploration.
Here, we utilized solid-phase synthesis to obtain a polycrystalline sample of
PbCu(PO)O. X-ray diffraction confirmed its structural
consistency with referenced literature. Zero resistance, which is important
evidence for superconductivity, was observed above 100 K under ambient
pressure in our experiment. Our finding indicates that
PbCu(PO)O is a possible candidate for searching
high-temperature superconductors.Comment: 7 pages, 3 figure
Screening and identification of Bifidobacterium longum from maternal milk and its domestication of oxygen-domestication
Objective: To screen Bifidobacterium from breast milk and improve its oxygen tolerance under aerobic conditions. Methods: Dilution and spread plate methods were performed to separate and screen Bifidobacterium from breast milk. Their Bifidobacterium identifications were characterized by 16S rDNA sequencing. The oxygen tolerant domestications were conducted through gradual increase of oxygen pressure and alternation of aerobic and anaerobic cultivations. Results: A novel Bifidobacterium strain was isolated from human milk and was identified as Bifidobacterium longum by 16S rDNA sequencing, which was named as MEFZ-2201. The homology between MEFZ-2201 and model strain (accession number in NCBI: ON631733.1) reached 100%. After oxygen tolerant domestication, the highest viable bacteria number of Bifidobacterium longum MEFZ-2201d in aerobic cultivation reached 8.9×109 CFU/mL, which was ten times higher than that of its wild-type strain MEFZ-2201. Whereas, the morphological property and physio-biochemical characteristics of Bifidobacterium longum MEFZ-2201d did not change after oxygen tolerant domestication. The short-chain fatty acid production of domesticated strain Bifidobacterium longum MEFZ-2201d was also significantly higher than that of its wild-type strain even under anaerobic conditions. Conclusion: A novel Bifidobacterium longum strain MEFZ-2201 was isolated from breast milk. The viable bacterium number of its domesticated strain MEFZ-2201d was significantly increased under aerobic conditions, indicating that it would be a potential probiotic strain for further development and utilization
Synthesis and biological evaluation of novel 1,2,3-triazole hybrids of cabotegravir: identification of potent antitumor activity against lung cancer
In pursuit of discovering novel anticancer agents, we designed and synthesized a series of novel 1,2,3-triazole hybrids based on cabotegravir analogues. These compounds were subjected to initial biological evaluations to assess their anticancer activities against non-small-cell lung cancer (NSCLC). Our findings indicated that some of these compounds exhibited promising antitumor abilities against H460 cells, while demonstrated less efficacy against H1299 cells. Notably, compound 5i emerged as the most potent, displaying an IC50 value of 6.06 μM. Furthermore, our investigations into cell apoptosis and reactive oxygen species (ROS) production revealed that compound 5i significantly induced apoptosis and triggered ROS generation. Additionally, Western blot analysis revealed the pronounced elevation of LC3 expression in H460 cells and γ-H2AX expression in H1299 cells subsequent to treatment with compound 5i. These molecular responses potentially contribute to the observed cell death phenomenon. These findings highlight the potential of compound 5i as a promising candidate for further development as an anticancer agent especially lung cancer
Genome-wide characterization of SOS1 gene family in potato (Solanum tuberosum) and expression analyses under salt and hormone stress
Salt Overly Sensitive 1 (SOS1) is one of the members of the Salt Overly Sensitive (SOS) signaling pathway and plays critical salt tolerance determinant in plants, while the characterization of the SOS1 family in potato (Solanum tuberosum) is lacking. In this study, 37 StSOS1s were identified and found to be unevenly distributed across 10 chromosomes, with most of them located on the plasma membrane. Promoter analysis revealed that the majority of these StSOS1 genes contain abundant cis-elements involved in various abiotic stress responses. Tissue specific expression showed that 21 of the 37 StSOS1s were widely expressed in various tissues or organs of the potato. Molecular interaction network analysis suggests that 25 StSOS1s may interact with other proteins involved in potassium ion transmembrane transport, response to salt stress, and cellular processes. In addition, collinearity analysis showed that 17, 8, 1 and 5 of orthologous StSOS1 genes were paired with those in tomato, pepper, tobacco, and Arabidopsis, respectively. Furthermore, RT-qPCR results revealed that the expression of StSOS1s were significant modulated by various abiotic stresses, in particular salt and abscisic acid stress. Furthermore, subcellular localization in Nicotiana benthamiana suggested that StSOS1-13 was located on the plasma membrane. These results extend the comprehensive overview of the StSOS1 gene family and set the stage for further analysis of the function of genes in SOS and hormone signaling pathways
Substrate interaction inhibits γ-secretase production of amyloid-β peptides
Combining NMR, mass spectrometry, AlphaLISA and cell assays, we discovered a compound C1 that binds C-terminal juxtamembrane lysines at the transmembrane domain of the amyloid precursor protein (APPTM) and inhibits γ-secretase production of amyloid-β with μM IC50. Our work suggests that targeting APPTM is a novel and viable strategy in AD drug discovery.This work was supported by a grant from the Warren Alpert Foundation (to C. W.), the NIH grant R21-NS109926 (to C. W.), NIH grants R01-AG008200 and RF1-NS047229 (to N. K. R.), and the NIH grant R35-GM127040 (to Y. Z.)Peer reviewe
In-situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory
The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole using 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. A unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. Birefringent light propagation has been examined as a possible explanation for this effect. The predictions of a first-principles birefringence model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties do not only include the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube LED calibration data, the theory and parametrization of the birefringence effect, the fitting procedures of these parameterizations to experimental data as well as the inferred crystal properties.</p
In situ estimation of ice crystal properties at the South Pole using LED calibration data from the IceCube Neutrino Observatory
The IceCube Neutrino Observatory instruments about 1 km3 of deep, glacial ice at the geographic South Pole. It uses 5160 photomultipliers to detect Cherenkov light emitted by charged relativistic particles. An unexpected light propagation effect observed by the experiment is an anisotropic attenuation, which is aligned with the local flow direction of the ice. We examine birefringent light propagation through the polycrystalline ice microstructure as a possible explanation for this effect. The predictions of a first-principles model developed for this purpose, in particular curved light trajectories resulting from asymmetric diffusion, provide a qualitatively good match to the main features of the data. This in turn allows us to deduce ice crystal properties. Since the wavelength of the detected light is short compared to the crystal size, these crystal properties include not only the crystal orientation fabric, but also the average crystal size and shape, as a function of depth. By adding small empirical corrections to this first-principles model, a quantitatively accurate description of the optical properties of the IceCube glacial ice is obtained. In this paper, we present the experimental signature of ice optical anisotropy observed in IceCube light-emitting diode (LED) calibration data, the theory and parameterization of the birefringence effect, the fitting procedures of these parameterizations to experimental data, and the inferred crystal properties.Peer Reviewe
TXS 0506+056 with Updated IceCube Data
Past results from the IceCube Collaboration have suggested that the blazar TXS 0506+056 is a potential source of astrophysical neutrinos. However, in the years since there have been numerous updates to event processing and reconstruction, as well as improvements to the statistical methods used to search for astrophysical neutrino sources. These improvements in combination with additional years of data have resulted in the identification of NGC 1068 as a second neutrino source candidate. This talk will re-examine time-dependent neutrino emission from TXS 0506+056 using the most recent northern-sky data sample that was used in the analysis of NGC 1068. The results of using this updated data sample to obtain a significance and flux fit for the 2014 TXS 0506+056 "untriggered" neutrino flare are reported
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