Quantum simulation studies have been performed on metal-ammonia solutions for a wide range of concentrations using a model consisting of excess electrons in a molecular solvent. At low electron concentrations, the electron density is localized, and the electrons pair to form peanut-shaped bipolarons. At higher electron concentrations, the bipolarons exhibit a tendency to cluster. Eventually, at yet higher concentrations, the electron density becomes delocalized and spans the system indicating that the system has become metallic. PACS numbers: 71.20.Cf, 71.25.Lf, 71.30.+h The general behavior of metal-ammonia solutions has been deduced from decades of experimental study [1][2][3]. At very low metal density, the solutions are characterized by isolated excess electrons [p e <0.01 mole percent electron (MPE)]. At higher concentrations (p e < 2 MPE), the solutions are dominated by localized spin paired species (bipolarons). The metal-insulator transition occurs at about 4 MPE, and, for concentrations greater than 9 MPE, the solution behaves like a good liquid metal. Although the available experimental information is extensive, the microscopic understanding of the electronic states of the system is mostly qualitative, especially at concentrations in the metallic regime [4,5].Previous simulation studies employing path integral Monte Carlo (PIMC) and Car-Parrinello local spin density functional (CP-LSDA) methods have confirmed experimental inferences about the electronic states at low metal concentration [6][7][8][9][10][11]. At infinite dilution, the excess electrons exist in the separate cavities about 3-4 A in radius. The surrounding ammonia molecules are ordered with, on average, one N-H bond pointing towards the center of the cavity occupied by the electron [6-9]. At around 1 MPE, the electron density is still localized. However, the electrons spin pair and form peanut-shaped cavities with peaks in the electron density about 7 A apart [10,11]. These spin paired species are the so-called "bipolarons." This weakly paired state is consistent with many experimental observations [4,10].In order to obtain a more complete understanding of the metal-ammonia phase diagram at higher metal density and to observe the onset of metallic behavior, CP-LSDA calculations [12][13][14] have been performed for concentrations that range from the insulating to the metallic regime (1-10 MPE). In particular, three electron densities, 1, 2, and 10 MPE, have been investigated. At 1 MPE, our new calculations confirm that the electron density is a localized bipolaronic structure [10,11]. At 2 MPE, bipolarons are still observed, but have a tendency to cluster. At 10 MPE, the electron density has become extended and spans the entire simulation cell in accord with the experimental data.In the present calculations, the solvent ammonia molecules are described by a rigid point-charge model [15]. The pseudopotential used to describe electron-ammonia interactions has been discussed in detail elsewhere [16]. It contains the appropriate electrostatic ...

Single-stage anterior debridement, strut autografting, posterior instrumentation, and fusion proved safe and effective for MTSUTR, which can achieve goals of complete spinal cord decompression and good deformity correction.

The limited therapeutic effect on hypoxic and refractory solid tumors has hindered the practical application of photodynamic therapy. Herein, we report our investigation of an osmium-peroxo complex (Os2), which is inactive in the dark, but can release a peroxo ligand O2•− upon light irradiation even in the absence of oxygen, and is transformed into a cytotoxic osmium complex (Os1). Os1 is cytotoxic in the presence or absence of irradiation in hypoxic tumors, behaving as a chemotherapeutic drug. At the same time, the light-activated Os2 induces photocatalytic oxidation of endogenous 1,4-dihydronicotinamide adenine dinucleotide in living cancer cells, leading to ferroptosis, which is mediated by glutathione degradation, lipid peroxide accumulation and down-regulation of glutathione peroxidase 4. In vivo studies have confirmed that the Os2 can effectively inhibit the growth of solid hypoxic tumors in mice. A promising strategy is proposed for the treatment of hypoxic tumors with metal-based drugs.

BackgroundIrritable bowel syndrome (IBS) is a common functional bowel disorder. The post-infectious IBS (PI-IBS) occurs in IBS patients with a history of intestinal infection preceding the onset of symptoms. However, the underlying cause of PI-IBS is not fully understood, and the purpose of this study was to investigate the immune regulatory mechanism of PI-IBS.MethodsParticipants enrolled in this study were divided into three groups including PI-IBS patients (n = 20), IBS patients without a history of infection (non-PI-IBS, n = 18), and healthy controls (n = 20). The expression levels of the Th1-derived cytokines IFN-γ and IL-12, and the Th2-derived cytokines IL-4 and IL-10 in the mucosal specimens, and in the ascending colon, the descending colon, and the rectal segments were measured by RT-PCR and western blot.ResultsThe IFN-γ mRNA levels in the intestinal mucosa were significantly higher in the PI-IBS group than in the non-PI-IBS or control group (both P < 0.05), but there was no difference between the non-PI-IBS and control groups. A trend toward IFN-γ protein upregulation was found in the PI-IBS group, while the IL-12 and IL-4 mRNA and protein levels were not different between any groups. The IL-10 mRNA and protein levels in the PI-IBS group were both significantly lower than in the non-PI-IBS or control groups (P < 0.05, respectively), but there was no difference between the non-PI-IBS and control groups. There were no differences in the cytokine mRNA and protein levels among the ascending colon, the descending colon, and the rectum of all groups.ConclusionsAn increase in IFN-γ levels and a decrease in IL-10 levels were found in the intestinal mucosa of PI-IBS patients, suggesting that the infection may affect the Th1/Th2 balance. Thus, the dysregulation of the immune response is likely an important cause of IBS.