Hydrogen Generation Catalyzed by Fluorinated Diglyoxime−Iron Complexes at Low Overpotentials

Fe^(II) complexes containing the fluorinated ligand 1,2-bis(perfluorophenyl)ethane-1,2-dionedioxime (dAr^FgH_2; H = dissociable proton) exhibit relatively positive Fe^(II/I) reduction potentials. The air-stable difluoroborated species [(dAr^FgBF_2)_2Fe(py)_2] (2) electrocatalyzes H_2 generation at −0.9 V vs SCE with i_(cat)/i_p ≈ 4, corresponding to a turnover frequency (TOF) of ~ 20 s^(–1) [Faradaic yield (FY) = 82 ± 13%]. The corresponding monofluoroborated, proton-bridged complex [(dArFg2H-BF2)Fe(py)2] (3) exhibits an improved TOF of ~ 200 s^(–1) (i_(cat)/i_p ≈ 8; FY = 68 ± 14%) at −0.8 V with an overpotential of 300 mV. Simulations of the electrocatalytic cyclic voltammograms of 2 suggest rate-limiting protonation of an Fe“0” intermediate (k_(RLS) ≈ 200 M^(–1) s^(–1)) that undergoes hydride protonation to form H_2. Complex 3 likely reacts via protonation of an Fe^I intermediate that subsequently forms H_2 via a bimetallic mechanism (k_(RLS) ≈ 2000 M^(–1) s^(–1)). 3 catalyzes production at relatively positive potentials compared with other iron complexes

Fe_4 Cluster and a Buckled Macrocycle Complex from the Reduction of [(dmgBF_2)_(2)Fe(L)_2] (L = MeCN, ^(t)Bu^(i)NC)

We report the syntheses, X-ray structures, and reductive electrochemistry of the Fe^(II) complexes [(dmgBF_2)_(2)Fe(MeCN)_2] (1; dmg = dimethylglyoxime, MeCN = acetonitrile) and [(dmgBF_2)Fe(^(t)Bu^(i)NC)_2] (2; ^(t)Bu^(i)NC = tert-butylisocyanide). The reaction of 1 with Na/Hg amalgam led to isolation and the X-ray structure of [(dmgBF_2)_(2)Fe(glyIm)] (3; glyIm = glyimine), wherein the (dmgBF_2)_2 macrocyclic frame is bent to accommodate the binding of a bidentate apical ligand. We also report the X-ray structure of a rare mixed-valence Fe4 cluster with supporting dmg-type ligands. In the structure of [(dmg_(2)BF_2)_(3)Fe_3(1/2dmg)_(3)Fe(O)_6] (4), the (dmgBF_(2))_2 macrocycle has been cleaved, eliminating BF_2 groups. Density functional theory calculations and electron paramagnetic resonance data are in accordance with a central FeIII ion surrounded by three formally Fe^(II)dmg_(2)BF_2 units

Integrating multi-level values and pro-environmental behavior in a U.S. protected area

Human behavior is influenced by an array of psychological processes such as environmental values. Despite the importance of understanding the reasons why people engage in activities that minimize environmental degradation, empirical research rarely integrates different types of values simultaneously to provide more complete and multi-faceted insights on how values contribute to environmental sustainability. Drawing from on-site survey data collected in Denali National Park and Preserve, Alaska (n = 641), we used two-step structural equation modeling to test how variation in behavioral patterns was explained by the cultural, individual, and social values of visitors to a national park. We fused various disciplinary perspectives on the value concept to demonstrate how individual- and group-level dynamics were integral for predicting behavior and better understanding aggregated preferences for environmental conditions in the context of a U.S. protected area.Peer reviewe

YY1 coopère avec AP-2 pour stimuler l'expression du gène ERBB2 dans les cellules de cancer du sein

peer reviewedOverexpression of the ERBB2 oncogene is observed in about 30% of breast cancers and is generally correlated with a poor prognosis. Previous results from our and other laboratories indicated that elevated transcriptional activity contributes significantly to the overexpression of ERBB2 mRNA in mammary adenocarcinoma cell lines. Activator protein 2 (AP-2) transcription factors account for this overexpression through two recognition sequences located 215 and 500 bp upstream from the transcription start site. Furthermore, AP-2 transcription factors are highly expressed in cancer cell lines overexpressing ERBB2. In this report, we examined the cooperative effect of Yin Yang 1 (YY1) on AP-2-induced activation of ERBB2 promoter activity. We detected high levels of YY1 transcription factor in mammary cancer cell lines. Notably, we showed that YY1 enhances AP-2alpha transcriptional activation of the ERBB2 promoter through an AP-2 site both in HepG2 and in HCT116 cells, whereas a carboxyl-terminal-truncated form of YY1 cannot. Moreover, we demonstrated the interaction between endogenous AP-2 and YY1 factors in the BT-474 mammary adenocarcinoma cell line. In addition, inhibition of endogenous YY1 protein by an antisense decreased the transcription of an AP-2-responsive ERBB2 reporter plasmid in BT-474 breast cancer cells. Finally, we detected in vivo AP-2 and YY1 occupancy of the ERBB2 proximal promoter in chromatin immunoprecipitation assays. Our data thus provide evidence that YY1 cooperates with AP-2 to stimulate ERBB2 promoter activity through the AP-2 binding sites

Over-Expression of LEDGF/p75 in HEp-2 Cells Enhances Autoimmune IgG Response in Patients with Benign Prostatic Hyperplasia : A Novel Diagnostic Approach with Therapeutic Consequence?

Lens epithelium-derived growth factor splice variant of 75 kDa (LEDGF/p75) is an autoantigen over-expressed in solid tumors and acts as a stress-related transcriptional co-activator. Participation of autoimmune responses in the pathophysiology of benign prostatic hyperplasia (PBH) and a corresponding immunosuppressive therapy by TNFalpha antagonists has been recently suggested. Thus, autoAb testing could aid in the diagnosis of BPH patients profiting from such therapy. We generated CRISPR/Cas9 modified HEp-2 LEDGF knock-out (KO) and HEp-2 LEDGF/p75 over-expressing (OE) cells and examined IgG autoantibody reactivity to LEDGF/p75 in patients with prostate cancer (PCa, n = 89), bladder cancer (BCa, n = 116), benign prostatic hyperplasia (BPH, n = 103), and blood donors (BD, n = 60) by indirect immunofluorescence assay (IFA). Surprisingly, we could not detect elevated binding of autoAbs against LEDGF/p75 in cancer patients, but autoAb reactivity to LEDGF/p75 OE cells in about 50% of patients with BPH was unexpectedly significantly increased. Furthermore, a line immunoassay enabling the detection of 18 different autoAbs revealed a significantly increased occurrence of anti-dsDNA autoAbs in 34% of BPH patients in contrast to tumor patients and BD. This finding was confirmed by anti-mitochondrial (mDNA) autoAb detection with the Crithidia luciliae immunofluorescence test, which also showed a significantly higher prevalence (34%) of anti-mDNA autoAbs in BPH. In summary, our study provided further evidence for the occurrence of autoimmune responses in BPH. Furthermore, LEDGF/p75 over-expression renders HEp-2 cells more autoantigenic and an ideal target for autoAb analysis in BPH with a potential therapy consequence

The diencephalon of the mink. I. The nuclear pattern of the dorsal thalamus

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49950/1/900950305_ftp.pd