Reverse charge transfer and decomposition in Ca-Te compounds under high pressure.

Pressure alters the nature of chemical bonds and triggers novel reactions. Here, we employed first-principles calculations combined with the CALYPSO structural search technique to reveal the charge transfer reversal between Ca and Te under high pressure in the calcium-tellurium compound (CaxTe1-x, x = 1/4, 1/3, 1/2, 2/3). We predict several new phases with conventional and unconventional compounds and found an unfamiliar phenomenon: the Ca-Te compounds will reverse charge transfer between Ca and Te atoms and decompose into elemental solids under pressure. The Bader charge analyses indicate that the Ca2+ ion gains electrons and becomes an anion under high pressure. This leads to a weakened electrostatic interaction between Ca and Te and ultimately results in decomposition. The calculated band occupation number suggests that the occupation of Ca 3d orbitals under high pressure corresponds to this atypical phenomenon. Our results demonstrated the reverse charge transfer between Ca and Te and, in addition, clarified the mechanism of CaxTe1-x decomposition into solid Ca and Te elements under high pressure, providing important insights into the evolution of the properties of alkaline-earth chalcogenide compounds under high pressure.

Ubiquitous occurrence of chlorinated byproducts of bisphenol A and nonylphenol in bleached food contacting papers and their implications for human exposure.

The occurrence of bisphenol A (BPA), nonylphenol (NP), and their six chlorinated byproducts were investigated in 74 food contacting papers (FCPs) from China, the U.S.A., Japan, and Europe using a sensitive dansylation LC-MS/MS method. BPA (

Early prediction of response to Vorinostat in an orthotopic rat glioma model.

Glioblastoma is the most common primary brain tumor and is uniformly fatal despite aggressive surgical and adjuvant therapy. As survival is short, it is critical to determine the value of therapy early on in treatment. Improved early predictive assessment would allow neuro-oncologists to personalize and adjust or change treatment sooner to maximize the use of efficacious therapy. During carcinogenesis, tumor suppressor genes can be silenced by aberrant histone deacetylation. This epigenetic modification has become an important target for tumor therapy. Suberoylanilide hydroxamic acid (SAHA, Vorinostat, Zolinza) is an orally active, potent inhibitor of histone deacetylase (HDAC) activity. A major shortcoming of the use of HDAC inhibitors in the treatment of patients with brain tumors is the lack of reliable biomarkers to predict and determine response. Histological evaluation may reflect tumor viability following treatment, but is an invasive procedure and impractical for glioblastoma. Another problem is that response to SAHA therapy is associated with tumor redifferentiation and cytostasis rather than tumor size reduction, thus limiting the use of traditional imaging methods. A noninvasive method to assess drug delivery and efficacy is needed. Here, we investigated whether changes in (1)H MRS metabolites could render reliable biomarkers for an early response to SAHA treatment in an orthotopic animal model for glioma. Untreated tumors exhibited significantly elevated alanine and lactate levels and reduced inositol, N-acetylaspartate and creatine levels, typical changes reported in glioblastoma relative to normal brain tissues. The (1)H MRS-detectable metabolites of SAHA-treated tumors were restored to those of normal-like brain tissues. In addition, reduced inositol and N-acetylaspartate were found to be potential biomarkers for mood alteration and depression, which may also be alleviated with SAHA treatment. Our study suggests that (1)H MRS can provide reliable metabolic biomarkers at the earliest stage of SAHA treatment to predict the therapeutic response.