Efficient Bimolecular Mechanism of Photochemical Hydrogen Production Using Halogenated Boron-Dipyrromethene (Bodipy) Dyes and a Bis(dimethylglyoxime) Cobalt(III) Complex

A series of Boron-­dipyrromethene (Bodipy) dyes were used as photosensitizers for photochemical hydrogen production in conjunction with [CoIII(dmgH)2pyCl] (where dmgH = dimethylglyoximate, py = pyridine) as the catalyst and triethanolamine (TEOA) as the sacrificial electron donor. The Bodipy dyes are fully characterized by electrochemistry, x-­‐ray crystallography, quantum chemistry calculations, femtosecond transient absorption and time-­‐resolved fluorescence, as well as in long-­‐term hydrogen production assays. Consistent with other recent reports, only systems containing halogenated chromophores were active for hydrogen production, as the long-­‐lived triplet state is necessary for efficient bimolecular electron transfer. Here, it is shown that the photostability of the system improves with Bodipy dyes containing a mesityl group versus a phenyl group, which is attributed to increased electron donating character of the mesityl substituent. Unlike previous reports, the optimal ratio of chromophore to catalyst is established and shown to be 20:1, at which point this bimolecular dye/catalyst system performs 3-­‐4 times better than similar chemically linked systems. We also show that the hydrogen production drops dramatically with excess catalyst concentration. The maximum turnover number of ~700 (with respect to chromophore) is obtained under the following conditions: 1.0 × 10­‐4 M [Co(dmgH)2pyCl], 5.0 × 10-6 M Bodipy dye with iodine and mesityl substituents, 1:1 v:v (10% aqueous TEOA):MeCN (adjusted to pH 7), and irradiation by light with λ \u3e 410 nm for 30 h. This system, containing discrete chromophore and catalyst, is more active than similar linked Bodipy – Co(dmg)2 dyads recently published, which, in conjunction with our other measurements, suggests that the nominal dyads actually function bimolecularly

Pre-Treatment With Glucagon-Like Peptide-1 Protects Against Ischemic Left Ventricular Dysfunction and Stunning Without a Detected Difference in Myocardial Substrate Utilization

AbstractObjectivesThis study sought to determine whether pre-treatment with intravenous glucagon-like peptide-1 (GLP-1)(7-36) amide could alter myocardial glucose use and protect the heart against ischemic left ventricular (LV) dysfunction during percutaneous coronary intervention.BackgroundGLP-1 has been shown to have favorable cardioprotective effects, but its mechanisms of action remain unclear.MethodsTwenty patients with preserved LV function and single-vessel left anterior descending coronary artery disease undergoing elective percutaneous coronary intervention were studied. A conductance catheter was placed into the LV, and pressure-volume loops were recorded at baseline, during 1-min low-pressure balloon occlusion (BO), and at 30-min recovery. Patients were randomized to receive an infusion of either GLP-1(7-36) amide at 1.2 pmol/kg/min or saline immediately after baseline measurements. Simultaneous coronary artery and coronary sinus blood sampling was performed at baseline and after BO to assess transmyocardial glucose concentration gradients.ResultsBO caused both ischemic LV dysfunction and stunning in the control group but not in the GLP-1 group. Compared with control subjects, the GLP-1 group had a smaller reduction in LV performance during BO (delta dP/dTmax, –4.3 vs. –19.0%, p = 0.02; delta stroke volume, –7.8 vs. –26.4%, p = 0.05), and improved LV performance at 30-min recovery. There was no difference in transmyocardial glucose concentration gradients between the 2 groups.ConclusionsPre-treatment with GLP-1(7-36) amide protects the heart against ischemic LV dysfunction and improves the recovery of function during reperfusion. This occurs without a detected change in myocardial glucose extraction and may indicate a mechanism of action independent of an effect on cardiac substrate use. (Effect of Glucgon-Like-Peptide-1 [GLP-1] on Left Ventricular Function During Percutaneous Coronary Intervention [PCI]; ISRCTN77442023

Research on atmospheric volcanic emissions: An overview

The project Research on Atmospheric Volcanic Emissions is a unique effort by NASA and university scientists to investigate the detailed chemical nature of plumes from volcanic eruptions. The major goals of the project are to: 1) understand the impact major eruptions will have on atmospheric chemistry processes, 2) understand the importance of volcanic emissions in the atmospheric geochemical cycles of selected species, 3) use knowledge of the plume chemical composition to diagnose and predict magmatic processes. Project RAVE\u27S first mission used the NASA Lockheed Orion P-3 outfitted with equipment to measure concentrations of the gases SO2, OCS, H2S, CS2, NO, O3and trace elements in particles in Mt. St. Helens\u27 plume on September 22, 1980. Measurements of SO2 column densities in the plume permitted calculations of SO2 fluxes. This article is an overview of the first experimental design factors and performance of the initial RAVE experiment

Common cancer-associated imbalances in the DNA damage response confer sensitivity to single agent ATR inhibition

ATR is an attractive target in cancer therapy because it signals replication stress and DNA lesions for repair and to S/G2 checkpoints. Cancer-specific defects in the DNA damage response (DDR) may render cancer cells vulnerable to ATR inhibition alone. We determined the cytotoxicity of the ATR inhibitor VE-821 in isogenically matched cells with DDR imbalance. Cell cycle arrest, DNA damage accumulation and repair were determined following VE-821 exposure. Defects in homologous recombination repair (HRR: ATM, BRCA2 and XRCC3) and base excision repair (BER: XRCC1) conferred sensitivity to VE-821. Surprisingly, the loss of different components of the trimeric non-homologous end-joining (NHEJ) protein DNA-PK had opposing effects. Loss of the DNA-binding component, Ku80, caused hypersensitivity to VE-821, but loss of its partner catalytic subunit, DNA-PKcs, did not. Unexpectedly, VE-821 was particularly cytotoxic to human and hamster cells expressing high levels of DNA-PKcs. High DNA-PKcs was associated with replicative stress and activation of the DDR. VE-821 suppressed HRR, determined by RAD51 focus formation, to a greater extent in cells with high DNA-PKcs. Defects in HRR and BER and high DNA-PKcs expression, that are common in cancer, confer sensitivity to ATR inhibitor monotherapy and may be developed as predictive biomarkers for personalised medicine

Full breastfeeding protection against common enteric bacteria and viruses: Results from the MAL-ED cohort study

Background: Breastfeeding is known to reduce risk of enteropathogen infections, but protection from specific enteropathogens is not well characterized.Objective: To estimate the association between full breastfeeding (days fed breast milk exclusively or with non-nutritive liquids) and enteropathogen detection.Design: 2,145 newborns were enrolled in eight sites, of whom 1,712 had breastfeeding and key enteropathogen data through 6 months. We focused on eleven enteropathogens: adenovirus 40/41, norovirus, sapovirus, astrovirus, and rotavirus, enterotoxigenic Escherichia coli (ETEC), Campylobacter spp, and typical enteropathogenic E. coli as well as entero-aggregative E. coli, Shigella and Cryptosporidium. Logistic regression was used to estimate the risk of enteropathogen detection in stools and survival analysis to estimate the timing of first detection of an enteropathogen.Results: Infants with 10% more days of full breastfeeding within the preceding 30 days of a stool sample were less likely to have the three E. Coli and Campylobacter spp detected in their stool (mean odds 0.92-0.99) but equally likely (0.99-1.02) to have the viral pathogens detected in their stool. A 10% longer period of full breastfeeding from birth was associated with later first detection of the three E. Coli, Campylobacter, adenovirus, astrovirus, and rotavirus (mean hazard ratios of 0.52-0.75). The hazards declined and point estimates were not statistically significant at 3 months.Conclusions: In this large multi-center cohort study, full breastfeeding was associated with lower likelihood of detecting four important enteric pathogens in the first six months of life. These results also show that full breastfeeding is related to delays in the first detection of some bacterial and viral pathogens in the stool. As several of these pathogens are risk factors for poor growth during childhood, this work underscores the importance of exclusive or full breastfeeding during the first six months of life to optimize early health

Democracy in trade unions, democracy through trade unions?

Since the Webbs published Industrial Democracy at the end of the nineteenth century, the principle that workers have a legitimate voice in decision-making in the world of work – in some versions through trade unions, in others at least formally through separate representative structures – has become widely accepted in most west European countries. There is now a vast literature on the strengths and weaknesses of such mechanisms, and we review briefly some of the key interpretations of the rise (and fall) of policies and structures for workplace and board-level representation. We also discuss the mainly failed attempts to establish broader processes of economic democracy, which the eclipse of nationally specific mechanisms of class compromise makes again a salient demand. Economic globalization also highlights the need for transnational mechanisms to achieve worker voice (or more radically, control) in the dynamics of capital-labour relations. We therefore examine the role of trade unions in coordinating pressure for a countervailing force at European and global levels, and in the construction of (emergent?) supranational industrial relations. However, many would argue that unions cannot win legitimacy as democratizing force unless manifestly democratic internally. We therefore revisit debates on and dilemmas of democracy within trade unions, and examine recent initiatives to enhance democratization

Erythromycin-nonsusceptible Streptococcus pneumoniae in Children, 1999–2001

After increasing from 1995 to 1999, invasive erythromycin-nonsusceptible Streptococcus pneumoniae rates per 100,000 decreased 53.6% in children from Baltimore, Maryland (US), from 1999 to 2001, which was partially attributed to strains related to the mefE-carrying England14-9 clone. The decline in infection rates was likely due to the pneumococcal 7-valent conjugate vaccine

Full breastfeeding protection against common enteric bacteria and viruses : results from the MAL-ED cohort study

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