Phase formation of polycrystalline MgB2 at low temperature using nanometer Mg powder

The MgB2 superconductor synthesized in a flowing argon atmosphere using nanometer magnesium powder as the raw materials, denoted as Nano-MgB2, has been studied by the technique of in-situ high temperature resistance measurement (HT-RT measurement). The MgB2 phase is identified to form within the temperature range of 430 to 490 C, which is much lower than that with the MgB2 sample fabricated in the same gas environment using the micron-sized magnesium powder, denoted as Micro-MgB2, reported previously. The sample density of the Nano-MgB2 reaches 1.7 g/cm3 with a crystal porosity structure less than a micrometer, as determined by the scanning electron microscope (SEM) images, while the Micro-MgB2 has a much more porous structure with corresponding density of 1.0 g/cm3. This indicates that the Mg raw particle size, besides the sintering temperature, is a crucial factor for the formation of high density MgB2 sample, even at the temperature much lower than that of the Mg melting, 650 C. The X-ray diffraction (XRD) pattern shows a good MgB2 phase with small amount of MgO and Mg and the transition temperature, TC, of the Nano-MgB2 was determined as 39 K by the temperature dependent magnetization measurement (M-T), indicating the existence of a good superconducting property.Comment: 10 pages, 4 figure, Solid State Communicatio

2-Iodo-5-nitro­thio­phene

The title compound, C4H2INO2S, was synthesized by nitration of iodo­thio­phene with acetyl nitrate. The molecule is essentially planar, withthe nitro group tilted by 1.78 (19)° and the iodine atom displaced by 0.0233 (2) Å with respect to the thiophene ring. In the crystal structure, adjacent mol­ecules are linked through weak I⋯O inter­actions [3.039 (2)Å], forming chains extending along the b axis

1H-Pyrrole-2-carboxylic acid

In the title compound, C5H5NO2, the pyrrole ring and its carboxyl substituent are close to coplanar, with a dihedral angle of 11.7 (3)° between the planes. In the crystal structure, adjacent mol­ecules are linked by pairs of O—H⋯O hydrogen bonds to form inversion dimers. Additional N—H⋯O hydrogen bonds link these dimers into chains extending along the a axis

Methyl 3-[(1-butyl-1H-indol-3-yl)carbonyl­amino]propionate

In the title mol­ecule, C17H22N2O3, the mean plane of the terminal (C=O)OMe fragment and the indole plane form a dihedral angle of 78.94 (3)°. Inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains extended along the c axis. The crystal packing exhibits π–π inter­actions, indicated by the short distance of 3.472 (2) Å between the centroids of the five-membered heterocycles of neighbouring mol­ecules

1-Ethyl-1H,6H-pyrrolo[2,3-c]azepine-4,8(5H,7H)-dione

The title compound, C10H12N2O2, was synthesized by cyclization of 3-(1-ethyl­pyrrole-2-carboxamido)propanoic acid in the presence of polyphospho­ric acid and diphospho­rus pentoxide. In the crystal structure, adjacent mol­ecules are linked by N—H⋯O hydrogen bonds, forming chains extending along the b axis

The role of IMP dehydrogenase 2 in Inauhzin-induced ribosomal stress

The ‘ribosomal stress (RS)-p53 pathway’ is triggered by any stressor or genetic alteration that disrupts ribosomal biogenesis, and mediated by several ribosomal proteins (RPs), such as RPL11 and RPL5, which inhibit MDM2 and activate p53. Inosine monophosphate (IMP) dehydrogenase 2 (IMPDH2) is a rate-limiting enzyme in de novo guanine nucleotide biosynthesis and crucial for maintaining cellular guanine deoxy- and ribonucleotide pools needed for DNA and RNA synthesis. It is highly expressed in many malignancies. We previously showed that inhibition of IMPDH2 leads to p53 activation by causing RS. Surprisingly, our current study reveals that Inauzhin (INZ), a novel non-genotoxic p53 activator by inhibiting SIRT1, can also inhibit cellular IMPDH2 activity, and reduce the levels of cellular GTP and GTP-binding nucleostemin that is essential for rRNA processing. Consequently, INZ induces RS and the RPL11/RPL5-MDM2 interaction, activating p53. These results support the new notion that INZ suppresses cancer cell growth by dually targeting SIRT1 and IMPDH2

Assessing the Impact of Nuclear Mass Models on the Prediction of Synthesis Cross Sections for Superheavy Elements

Within the framework of the dinuclear system model, this study delves into the impact of various nuclear mass models on evaluating the fusion probability of superheavy nuclei. Nuclear mass models, as crucial inputs to the DNS model, exhibit slight variations in binding energy, quadrupole deformation, and extrapolation ability; these subtle differences can significantly influence the model's outcomes. Specifically, the study finds that nuclear mass plays a pivotal role in determining fusion probability, and Q-value. By numerically solving a set of master equations, the study examines how binding energies from different mass models affect the fusion probability of colliding nuclei, taking the example of $^{48}$Ca + $^{243}$Am $\rightarrow$ $^{291}$Mc. A careful analysis of the potential energy surface (PES) reveals that the inner fusion barriers lead to variations in fusion probabilities. Importantly, the study demonstrates that the synthesis cross sections of superheavy nuclei calculated using different nuclear mass models align well with experimental data, falling within an error range of one order of magnitude. This finding underscores the reliability of our model predictions. Looking ahead, the study utilizes five distinct nuclear mass models to predict the synthesis cross sections of superheavy elements 119 and 120, along with their associated uncertainties. These predictions offer valuable insights into the feasibility of synthesizing these elusive elements and pave the way for future experimental explorations

Heterologous SH3-p85β inhibits influenza A virus replication

Phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathway can support the replication of influenza A virus through binding of viral NS1 protein to the Src homology 3 (SH3) domain of p85β regulatory subunit of PI3K. Here we investigated the effect of heterologously overexpressed SH3 on the replication of different influenza A virus subtypes/strains, and on the phosphorylation of Akt in the virus-infected cells. We found that heterologous SH3 reduced replication of influenza A viruses at varying degrees in a subtype/strain-dependent manner and SH3 overexpression reduced the induction of the phosphorylation of Akt in the cells infected with PR8(H1N1) and ST364(H3N2), but not with ST1233(H1N1), Ph2246(H9N2), and Qa199(H9N2). Our results suggest that interference with the NS1-p85β interaction by heterologous SH3 can be served as a useful antiviral strategy against influenza A virus infection

A data analysis method for isochronous mass spectrometry using two time-of-flight detectors at CSRe

The concept of isochronous mass spectrometry (IMS) applying two time-of-flight (TOF) detectors originated many years ago at GSI. However, the corresponding method for data analysis has never been discussed in detail. Recently, two TOF detectors have been installed at CSRe and the new working mode of the ring is under test. In this paper, a data analysis method for this mode is introduced and tested with a series of simulations. The results show that the new IMS method can significantly improve mass resolving power via the additional velocity information of stored ions. This improvement is especially important for nuclides with Lorentz factor $\gamma$-value far away from the transition point $\gamma _t$ of the storage ring CSRe.Comment: published in Chinese Physics C Vol. 39, No. 10 (2015) 10620