Molecular catalysis of carbon dioxide reduction using earth-abundant metal complexes as catalysts is a key challenge related to the production of useful products--the "solar fuels"--in which solar energy would be stored. A direct approach using sunlight energy as well as an indirect approach where sunlight is first converted into electricity could be used. A Co(II) complex and a Fe(III) complex, both bearing the same pentadentate N5 ligand (2,13-dimethyl-3,6,9,12,18-pentaazabicyclo[12.3.1]octadeca-1(18),2,12,14,16-pentaene), were synthesized, and their catalytic activity toward CO2 reduction was investigated. Carbon monoxide was formed with the cobalt complex, while formic acid was obtained with the iron-based catalyst, thus showing that the catalysis product can be switched by changing the metal center. Selective CO2 reduction occurs under electrochemical conditions as well as photochemical conditions when using a photosensitizer under visible light excitation (λ > 460 nm, solvent acetonitrile) with the Co catalyst. In the case of the Fe catalyst, selective HCOOH production occurs at low overpotential. Sustained catalytic activity over long periods of time and high turnover numbers were observed in both cases. A catalytic mechanism is suggested on the basis of experimental results and preliminary quantum chemistry calculations.

The design of highly efficient and selective photocatalytic systems for CO2 reduction that are based on nonexpensive materials is a great challenge for chemists. The photocatalytic reduction of CO2 by [Co(qpy)(OH2)2](2+) (1) (qpy = 2,2':6',2″:6″,2‴-quaterpyridine) and [Fe(qpy)(OH2)2](2+) (2) have been investigated. With Ru(bpy)3(2+) as the photosensitizer and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole as the sacrificial reductant in CH3CN/triethanolamine solution under visible-light excitation (blue light-emitting diode), a turnover number (TON) for CO as high as 2660 with 98% selectivity can be achieved for the cobalt catalyst. In the case of the iron catalyst, the TON was >3000 with up to 95% selectivity. More significantly, when Ru(bpy)3(2+) was replaced by the organic dye sensitizer purpurin, TONs of 790 and 1365 were achieved in N,N-dimethylformamide for the cobalt and iron catalysts, respectively.

M II (qpy)(H 2 O) 2 ] 2+ (M = Fe, Co; qpy: 2,2′:6′,2″:6″,2‴-quaterpyridine) complexes efficiently catalyze the electrochemical CO 2 -to-CO conversion in acetonitrile solution in the presence of weak Bronsted acids. Upon performing cyclic voltammetry studies, controlled-potential electrolysis, and spectroelectrochemistry (UV−visible and infrared) experiments together with DFT calculations, catalytic mechanisms were deciphered. Catalysis is characterized by high selectivity for CO production (selectivity >95%) in the presence of phenol as proton source. Overpotentials as low as 240 and 140 mV for the Fe and Co complexes, respectively, led to large CO production for several hours. In the former case, the one-electron-reduced species binds to CO 2 , and CO evolution is observed after further reduction of the intermediate adduct. A deactivation pathway has been identified, which is due to the formation of a Fe 0 qpyCO species. With the Co catalyst, no such deactivation occurs, and the doubly reduced complex activates CO 2 . High scan rate cyclic voltammetry allows reaching kinetic conditions, leading to scan-rate-independent plateau-shaped voltammograms from which catalytic rate constant was obtained. The molecular catalyst is very active for CO production (turnover a frequency of 3.3 × 10 4 s −1 at 0.3 V overpotential), as confirmed by catalytic a Tafel plot showing a comparison with previous catalysts.

Polycomb group (PcG)-mediated gene silencing is a common developmental strategy used to maintain stably inherited repression of target genes and involves different protein complexes known as Polycomb-repressive complexes (PRCs). In animals, the two best-characterized PcG complexes are PRC1 and PRC2. In this report, we demonstrate that the plantspecific protein EMBRYONIC FLOWER1 (EMF1) functions in maintaining the repression of the flower homeotic gene AGAMOUS (AG) during vegetative development in Arabidopsis thaliana by acting in concert with the EMF2 complex, a putative equivalent of Drosophila melanogaster PRC2. We show that AG regulatory sequences are required for its ectopic expression in both emf1 and emf2 mutants and that EMF2 is required for trimethylation of histone 3 lysine 27 on the AG chromatin. We found that EMF1 interacts directly with AG and that this interaction depends on the presence of EMF2. Together with the finding of EMF1 interference with transcription in vitro, these results suggest that EMF1 enables transcriptional repression of AG after the action of the putative EMF2 complex. Our data indicate that EMF1 plays a PRC1-like role in the PcG-mediated floral repression mechanism.

Key Points• CXCL13 and CXCL12 mediate chemotaxis of CNS lymphoma cells, and CXCL13 concentration in CSF is prognostic.• CXCL13 plus IL-10 is highly specific for the diagnosis of CNS lymphoma.Establishing the diagnosis of focal brain lesions in patients with unexplained neurologic symptoms represents a challenge. The goal of this study is to provide evidence supporting functional roles for CXC chemokine ligand (CXCL)13 and interleukin (IL)-10 in central nervous system (CNS) lymphomas and to evaluate the utility of each as prognostic and diagnostic biomarkers. We demonstrate for the first time that elevated CXCL13 concentration in cerebrospinal fluid (CSF) is prognostic and that CXCL13 and CXCL12 mediate chemotaxis of lymphoma cells isolated from CNS lymphoma lesions. Expression of the activated form of Janus kinase 1 supported a role for IL-10 in prosurvival signaling. We determined the concentration of CXCL13 and IL-10 in CSF of CNS lymphoma patients and control cohorts including inflammatory and degenerative neurologic disease in a multicenter study involving 220 patients. Bivariate elevated CXCL13 plus IL-10 was 99.3% specific for primary and secondary CNS lymphoma, with sensitivity significantly greater than reference standard CSF tests. These results identify CXCL13 and IL-10 as potentially important biomarkers of CNS lymphoma that merit further evaluation and support incorporation of CXCL13 and IL-10 into diagnostic algorithms for the workup of focal brain lesions in which lymphoma is a consideration. (Blood. 2013;121(23):4740-4748) IntroductionDetermination of the pathological basis of focal brain lesions in patients with unexplained neurologic symptoms is a major clinical challenge. Persistent symptoms or rapid neurologic decline often mandates stereotactic brain biopsy, a highly invasive procedure with a 10% to 35% rate of diagnostic failure.1-3 Moreover, many lesions are not amenable to biopsy because of small size, location in deep brain structures, risk of hemorrhage, and other comorbidities.The diagnosis of central nervous system (CNS) involvement of non-Hodgkin lymphoma is a particular challenge because of lesional response to glucocorticoids and features on magnetic resonance imaging (MRI) that are shared with other pathologies including astrocytic neoplasms, demyelination, neurosarcoid, vasculitis, infections, and leptomeningeal dissemination of systemic cancer. Although flowcytometric and cytological analysis of cerebrospinal fluid (CSF) is useful in the evaluation of leptomeningeal disease, these tests are usually insensitive to pathological processes based in deep brain structures and rarely provide information that eliminates the need for brain biopsy; the sensitivity of CSF cytological analysis in the evaluation of primary CNS lymphoma (PCNSL) is ;15%. 4Advances that facilitate diagnosis and early treatment of CNS lymphoma would likely be cost-effective, minimize repeat diagnostic CSF and MRI evaluations and brain biopsies, and also lead to improved outcomes. [5][6][7] The molecular const...

Objectives Precarious employment (PE) is a term used to describe non-standard employment forms characterized by low security that may have negative effects on mental health. The objective of this review was to systematically review the evidence for effects of PE on mental health and identify important areas for further research. Methods A protocol was developed following PRISMA-P guidelines. Web of Science, PubMed and PsycINFO were searched up to 4 September 2017. All unique records were assessed for eligibility and quality by at least two reviewers. Data from included studies were summarized in forest plots and meta-analyses using a randomeffects model. Evidence quality was rated using the GRADE method. Results We obtained 3328 unique records, of which 16 studies of sufficient quality met the inclusion criteria. Moderate quality evidence (GRADE score 3 of 4) was found for an adverse effect of job insecurity on mental health; summary odds ratio (OR) 1.52 [95% confidence interval (CI) 1.35-1.70]. There was very low quality (GRADE 1 of 4) evidence for effects of temporary employment or unpredictable work hours on mental health. Five studies on multidimensional exposures all showed adverse effects, weighted average OR 2.01 (95% CI 1.60-2.53). Conclusions Research on PE and mental health is growing, but high-quality prospective studies are still scarce. Job insecurity likely has an adverse effect on mental health. A clear multi-dimensional definition of PE is lacking, and harmonization efforts are needed. Further single-variable observational studies on job insecurity or temporary employment should not be prioritized.

Achieving visible-light-driven carbon dioxide reduction with high selectivity control and durability while using only earth abundant elements requires new strategies. Hybrid catalytic material was prepared upon covalent grafting a Co−quaterpyridine molecular complex to semiconductive mesoporous graphitic carbon nitride (mpg-C 3 N 4) through an amide linkage. The molecular material was characterized by various spectroscopic techniques, including XPS, IR, and impedance spectroscopy. It proved to be a selective catalyst for CO production in acetonitrile using a solar simulator with a high 98% selectivity, while being remarkably robust since no degradation was observed after 4 days of irradiation (ca. 500 catalytic cycles). This unique combination of a selective molecular catalyst with a simple and robust semiconductive material opens new pathways for CO 2 catalytic light-driven reduction.

No abstract