Poly[diaqua­(μ2-oxalato-κ4 O 1,O 2:O 1′,O 2′)(μ2-pyrazine-2-carboxyl­ato-κ4 N 1,O:O,O′)neodymium(III)]

In the title complex, [Nd(C5H3N2O2)(C2O4)(H2O)2]n, the NdIII atom is ten-coordinated by one N atom and three O atoms from two pyrazine-2-carboxyl­ate ligands, four O atoms from two oxalate ligands and two water mol­ecules in a distorted bicapped square-anti­prismatic geometry. The two crystallographically independent oxalate ligands, each lying on an inversion center, act as bridging ligands, linking Nd atoms into an extended zigzag chain. Neighboring chains are linked by the pyrazine-2-carboxyl­ate ligands into a two-dimensional layerlike network in the (10) plane. The layers are further connected by O—H⋯O and O—H⋯N hydrogen bonds, forming a three-dimensional supra­molecular network

Stationary Response of a Class of Nonlinear Stochastic Systems Undergoing Markovian Jumps

Systems whose specifications change abruptly and statistically, referred to as Markovianjump systems, are considered in this paper. An approximate method is presented to assess the stationary response of multidegree, nonlinear, Markovian-jump, quasi-nonintegrable Hamiltonian systems subjected to stochastic excitation. Using stochastic averaging, the quasi-nonintegrable Hamiltonian equations are first reduced to a one-dimensional Itô equation governing the energy envelope. The associated Fokker-Planck-Kolmogorov equation is then set up, from which approximate stationary probabilities of the original system are obtained for different jump rules. The validity of this technique is demonstrated by using a nonlinear two-degree oscillator that is stochastically driven and capable of Markovian jumps

4-(4-Pyrid­yl)pyridinium 3′,4,4′-tricarboxy­biphenyl-3-carboxyl­ate dihydrate

In the title compound, C10H9N2 +·C16H9O8 −·2H2O, both the cation and anion possess crystallographically imposed centres of symmetry, causing the nitro­gen-bound H atom in the 4-(4-pyrid­yl)pyridinium cation and the acidic H atom of the carboxyl­ate groups at the 3 and 3′ positions in the anion to be disordered over two positions with equal occupancies. In the crystal packing, the cations, anions and water mol­ecules are connected by O—H⋯O, C—H⋯O and N—H⋯N hydrogen bonds, forming layers parallel to (20). These layer are further connected into a three-dimensional supra­molecular network by O—H⋯O hydrogen bonds involving the water mol­ecules as H-atom donors and by weak π–π stacking inter­actions between neighbouring benzene and pyridine rings, with centroid–centroid distances of 3.756 (5) Å

Research on the X-Ray Polarization Deconstruction Method Based on Hexagonal Convolutional Neural Network

Track reconstruction algorithms are critical for polarization measurements. In addition to traditional moment-based track reconstruction approaches, convolutional neural networks (CNN) are a promising alternative. However, hexagonal grid track images in gas pixel detectors (GPD) for better anisotropy do not match the classical rectangle-based CNN, and converting the track images from hexagonal to square results in loss of information. We developed a new hexagonal CNN algorithm for track reconstruction and polarization estimation in X-ray polarimeters, which was used to extract emission angles and absorption points from photoelectron track images and predict the uncertainty of the predicted emission angles. The simulated data of PolarLight test were used to train and test the hexagonal CNN models. For individual energies, the hexagonal CNN algorithm produced 15-30% improvements in modulation factor compared to moment analysis method for 100% polarized data, and its performance was comparable to rectangle-based CNN algorithm newly developed by IXPE team, but at a much less computational cost.Comment: 21 pages, 12 figures, submitted to NS

Archaeal Surface Layer Proteins Contain β Propeller, PKD, and β Helix Domains and Are Related to Metazoan Cell Surface Proteins

AbstractThe surface layer of archaeobacteria protects cells from extreme environments and, in Methanosarcina, may regulate cell adhesion. We identify three domain types that account for the complete architecture of numerous Methanosarcina surface layer proteins (SLPs). We solve the crystal structure for two of these domains, which correspond to the two N-terminal domains of an M. mazei SLP. One domain displays a unique, highly symmetrical, seven-bladed β propeller fold, and the other belongs to the polycystic kidney disease (PKD) superfamily fold. The third domain is predicted to adopt a β helix fold. These domains have homologs in metazoan cell surface proteins, suggesting remarkable relationships between domains in archaeal SLPs and metazoan cell surface proteins

Synthesis and Evaluation of Novel Organogermanium Sesquioxides As Antitumor Agents

Five new organogermanium sesquioxides have been synthesized and characterized by elemental analysis and IR spectra. All the compounds were tested for antitumor activities against KB, HCT, and Bel cells in vitro. Compound 5 (γ-thiocarbamido propyl germanium sesquioxide) showed excellent antitumor activity, and its inhibition yield to KB, HCT, and Bel cells was 92.9%, 84.9%, and 70.9%, respectively. A rapid method was described for the labeling compound 5 with 99mTc, and the optimum labeling conditions were investigated. The labeling yield is above 90% in pH 7.0, 20°C, reaction time greater than 10 minutes, 1 mg of compound 5, and 0.075∼0.1 mg of SnCl2. The biodistribution of 99mTc labeled compound 5 in nude mice bearing human colonic xenografts was studied. The result showed that the tumor uptakes were 0.73, 0.97, 0.87, and 0.62 ID%/g at 1-hour, 3-hour, 6-hour, and 20-hour postinjection, respectively. T/NT (the uptake ratio for per gram of tumor over normal tissues) was 18.3 for tumor versus brain and 5.81 for tumor versus muscle at 20-hour postinjection. The tumor clearance was slow. The results showed that compound 5 may be developed to be a suitable cancer therapeutic agent

Effects of Herb-Partitioned Moxibustion on the miRNA Expression Profiles in Colon from Rats with DSS-Induced Ulcerative Colitis

Objective. This study explored the mechanism of herb-partitioned moxibustion (HM) on dextran sulfate sodium- (DSS-) induced ulcerative colitis (UC) from the miRNA perspective. Methods. Rats were randomly divided into 3 groups [normal control (NC) group, UC model (UC) group, and herb-partitioned moxibustion (UCHM) group]. The UC and UCHM groups were administered 4% DSS for 7 days. The UCHM group received HM at the Tianshu (bilateral, ST25). The effect of HM on UC was observed and the miRNA expression profile in the colon tissues was analyzed. Results. Compared with the UC group, the body weights were significantly higher in the UCHM group on day 14 (P<0.001); the macroscopic colon injury scores and microscopic histopathology scores in the UCHM group decreased (P<0.05); and there were 15 differentially expressed miRNAs in the UCHM group. The changes in miR-184 and miR-490-5p expression levels on the UC were reversed by HM intervention. Validation using qRT-PCR showed that two miRNAs expression trend was consistent with the sequencing results. Conclusion. HM at ST25 might regulate miR-184 and miR-490-5p expression, act on the transcription of their target genes to regulate inflammatory signaling pathways, and attenuate inflammation and tissue injury in the colons of rats with DSS-induced UC

Model of a multiverse providing the dark energy of our universe

It is shown that the dark energy presently observed in our universe can be regarded as the energy of a scalar field driving an inflation-like expansion of a multiverse with ours being a subuniverse among other parallel universes. A simple model of this multiverse is elaborated: Assuming closed space geometry, the origin of the multiverse can be explained by quantum tunneling from nothing; subuniverses are supposed to emerge from local fluctuations of separate inflation fields. The standard concept of tunneling from nothing is extended to the effect that in addition to an inflationary scalar field, matter is also generated, and that the tunneling leads to an (unstable) equilibrium state. The cosmological principle is assumed to pertain from the origin of the multiverse until the first subuniverses emerge. With increasing age of the multiverse, its spatial curvature decays exponentially so fast that, due to sharing the same space, the flatness problem of our universe resolves by itself. The dark energy density imprinted by the multiverse on our universe is time-dependent, but such that the ratio $w{=}\varrho/(c^2p)$ of its mass density and pressure (times $c^2$) is time-independent and assumes a value $-1{+}\epsilon$ with arbitrary $\epsilon{>}0$. $\epsilon$ can be chosen so small, that the dark energy model of this paper can be fitted to the current observational data as well as the cosmological constant model.Comment: 32 pages, 4 figure