Electrochemical Hydrogen Compressor

The Electrochemical Hydrogen Compressor EHC was evaluated against DOE applications for compressing hydrogen at automobile filling stations, in future hydrogen pipelines and as a commercial replacement for conventional diaphragm hydrogen compressors. It was also evaluated as a modular replacement for the compressors used in petrochemical refineries. If the EHC can be made inexpensive, reliable and long lived then it can satisfy all these applications save pipelines where the requirements for platinum catalyst exceeds the annual world production. The research performed did not completely investigate Molybdenum as a hydrogen anode or cathode, it did show that photoetched 316 stainless steel is inadequate for an EHC. It also showed that: molybdenum bipolar plates, photochemical etching processes, and Gortex Teflon seals are too costly for a commercial EHC. The use of carbon paper in combination with a perforated thin metal electrode demonstrated adequate anode support strength, but is suspect in promoting galvanic corrosion. The nature of the corrosion mechanisms are not well understood, but locally high potentials within the unit cell package are probably involved. The program produced a design with an extraordinary high cell pitch, and a very low part count. This is one of the promising aspects of the redesigned EHC. The development and successful demonstration of the hydraulic cathode is also important. The problem of corrosion resistant metal bipolar plates is vital to the development of an inexpensive, commercial PEM fuel cell. Our research suggests that there is more to the corrosion process in fuel cells and electrochemical compressors than simple, steady state, galvanic stability. It is an important area for scientific investigation. The experiments and analysis conducted lead to several recommended future research directions. First, we need a better understanding of the corrosion mechanisms involved. The diagnosis of experimental cells with titration to determine the loss of membrane active sites is recommended. We suspect that the corrosion includes more than simple galvanic mechanisms. The mechanisms involved in this phenomenon are poorly understood. Shunt currents at hydraulic cathode ports were problematic, but are not difficult to cure. In addition to corrosion there is evidence of high component resistivity. This may be due to the deposition of organic compounds, which may be produced electrochemically on the surface of the metal support screens that contact carbon gas diffusion layers (GDLs) or catalyst supports. An investigation of possible electro-organic sythesis mechanisms with emphasis on oxalates formation is warranted. The contaminated cell parts can be placed in an oxidizing atmosphere at high temperature and the weight loss can be observed. This would reveal the existence of organic compounds. Investigation into the effects of conductivity enhancers such as carbon microlayers on supporting carbon paper is also needed. Corrosion solutions should be investigated such as surface passivation of 316 SS parts using nitric acid. Ultra thin silane/siloxane polymer coatings should be tried. These may be especially useful in conjunction with metal felt replacement of carbon paper. A simple cure for the very high, localized corrosion of the anode might be to diffusion bond the metal electrode support screen to bipolar plate. This will insure uniform resistance perpendicular to the plane of the cell and eliminate some of the dependence of the resistance on high stack compression. Alternative materials should be explored. Alternatives to carbon in the cell may be helpful in any context. In particular, alternatives to carbon paper GDLs such as metal felts and alternatives to carbon supports for Pt such as TiC and TiB2 might also be worthwhile and would be helpful to fuel cells as well. Some alternative to the metals we used in the cell, Mo and 316 SS, are potentially useful. These include Al/Mg/Si alloys. Corrosion resistant materials such as Nb and Mo might prove useful as cladding materials that can be hot stamped. Several cost reduction areas should be explored. Such as the water pumps used in pressure washers. The power consumption of these pumps is a concern, but their cost is surprisingly low. Two components of unit cell construction proved to be extremely costly. The first of these is photoetching, where selective etching of alloys present a corrodible composition in the cell. An alternative to photoetching may be hot stamping. An investigation of materials for hot stamping and the dimension tolerance attainable with this process should be first on the agenda. Hot stamping of clad materials should also be studied. Photoetched electrode supports can be replaced with expanded metal screens (Dexmet). The other high cost area is the use of Gortex TFE seals. Analytic’s prior experience with Acrylic seals shows they can probably replace TFE

Monitoring the introduction of pneumococcal conjugate vaccines into West Africa: design and implementation of a population-based surveillance system.

Routine use of pneumococcal conjugate vaccines (PCVs) in developing countries is expected to lead to a significant reduction in childhood deaths. However, PCVs have been associated with replacement disease with non-vaccine serotypes. We established a population-based surveillance system to document the direct and indirect impact of PCVs on the incidence of invasive pneumococcal disease (IPD) and radiological pneumonia in those aged 2 months and older in The Gambia, and to monitor changes in serotype-specific IPD. Here we describe how this surveillance system was set up and is being operated as a partnership between the Medical Research Council Unit and the Gambian Government. This surveillance system is expected to provide crucial information for immunisation policy and serves as a potential model for those introducing routine PCV vaccination in diverse settings

Growing impact of restenosis on the surgical treatment of peripheral arterial disease

BACKGROUND: Patients with peripheral arterial disease often experience treatment failure from restenosis at the site of a prior peripheral endovascular intervention (PVI) or lower extremity bypass (LEB). The impact of these treatment failures on the utilization and outcomes of secondary interventions is poorly understood. METHODS AND RESULTS: In our regional vascular quality improvement collaborative, we compared 2350 patients undergoing primary infrainguinal LEB with 1154 patients undergoing secondary infrainguinal LEB (LEB performed after previous revascularization in the index limb) between 2003 and 2011. The proportion of patients undergoing secondary LEB increased by 72% during the study period (22% of all LEBs in 2003 to 38% in 2011, P\u3c0.001). In-hospital outcomes, such as myocardial infarction, death, and amputation, were similar between primary and secondary LEB groups. However, in both crude and propensity-weighted analyses, secondary LEB was associated with significantly inferior 1-year outcomes, including major adverse limb event-free survival (composite of death, new bypass graft, surgical bypass graft revision, thrombectomy/thrombolysis, or above-ankle amputation; Secondary LEB MALE-free survival = 61.6% vs primary LEB MALE-free survival = 67.5%, P=0.002) and reintervention or amputation-free survival (composite of death, reintervention, or above-ankle amputation; Secondary LEB RAO-free survival = 58.9% vs Primary LEB RAO-free survival 64.1%, P=0.003). Inferior outcomes for secondary LEB were observed regardless of the prior failed treatment type (PVI or LEB). CONCLUSIONS: In an era of increasing utilization of PVI, a growing proportion of patients undergo LEB in the setting of a prior failed PVI or surgical bypass. When caring for patients with peripheral arterial disease, physicians should recognize that first treatment failure (PVI or LEB) affects the success of subsequent revascularizations

Receptor selectivity between the G proteins Gα12 and Gα13 is defined by a single leucine-to-isoleucine variation

Despite recent advances in structural definition of GPCR–G protein complexes, the basis of receptor selectivity between G proteins remains unclear. The Gα12 and Gα13 subtypes together form the least studied group of heterotrimeric G proteins. G protein–coupled receptor 35 (GPR35) has been suggested to couple efficiently to Gα13 but weakly to Gα12. Using combinations of cells genome-edited to not express G proteins and bioluminescence resonance energy transfer–based sensors, we confirmed marked selectivity of GPR35 for Gα13. Incorporating Gα12/Gα13 chimeras and individual residue swap mutations into these sensors defined that selectivity between Gα13 and Gα12 was imbued largely by a single leucine-to-isoleucine variation at position G.H5.23. Indeed, leucine could not be substituted by other amino acids in Gα13 without almost complete loss of GPR35 coupling. The critical importance of leucine at G.H5.23 for GPR35–G protein interaction was further demonstrated by introduction of this leucine into Gαq, resulting in the gain of coupling to GPR35. These studies demonstrate that Gα13 is markedly the most effective G protein for interaction with GPR35 and that selection between Gα13 and Gα12 is dictated largely by a single conservative amino acid variation.—Mackenzie, A. E., Quon, T., Lin, L.-C., Hauser, A. S., Jenkins, L., Inoue, A., Tobin, A. B., Gloriam, D. E., Hudson, B. D., Milligan, G. Receptor selectivity between the G proteins Gα12 and Gα13 is defined by a single leucine-to-isoleucine variation

Functional Modeling Identifies Paralogous Solanesyl-diphosphate Synthases That Assemble the Side Chain of Plastoquinone-9 in Plastids

Background: Plastid isoforms of solanesyl-diphosphate synthase catalyze the elongation of the prenyl side chain of plastoquinone-9. Results: Corresponding mutants display lower levels of plastoquinone-9 and plastochromanol-8 and display intact levels of vitamin E. Conclusion: Plastochromanol-8 originates from a subfraction of non-photoactive plastoquinol-9 and is not essential for seed longevity. Significance: Viable plastoquinone-9 mutants are invaluable tools for understanding plastid metabolism

47.4: Blue Phosphorescent Organic Light Emitting Device Stability Analysis

A model based on defect generation by exciton‐polaron annihilation interactions between the emitter and host molecules, in a blue phosphorescent OLED, is shown to fit well with experimental data. A blue PHOLED with (0.15, 0.25) chromaticity is shown to have a half‐life, from 1,000 nits, of 690 hrs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92134/1/1.3069766.pd

Could Seals Prevent Cod Recovery in the Baltic Sea?

Fish populations are increasingly affected by multiple human and natural impacts including exploitation, eutrophication, habitat alteration and climate change. As a result many collapsed populations may have to recover in ecosystems whose structure and functioning differ from those in which they were formerly productive and supported sustainable fisheries. Here we investigate how a cod (Gadus morhua) population in the Baltic Sea whose biomass was reduced due to a combination of high exploitation and deteriorating environmental conditions might recover and develop in the 21st century in an ecosystem that likely will change due to both the already started recovery of a cod predator, the grey seal Halichoerus grypus, and projected climate impacts. Simulation modelling, assuming increased seal predation, fishing levels consistent with management plan targets and stable salinity, shows that the cod population could reach high levels well above the long-term average. Scenarios with similar seal and fishing levels but with 15% lower salinity suggest that the Baltic will still be able to support a cod population which can sustain a fishery, but biomass and yields will be lower. At present knowledge of cod and seal interactions, seal predation was found to have much lower impact on cod recovery, compared to the effects of exploitation and salinity. These results suggest that dual management objectives (recovery of both seal and cod populations) are realistic but success in achieving these goals will also depend on how climate change affects cod recruitment

Chemical informatics uncovers a new role for moexipril as a novel inhibitor of cAMP phosphodiesterase-4 (PDE4)

PDE4 is one of eleven known cyclic nucleotide phosphodiesterase families and plays a pivotal role in mediating hydrolytic degradation of the important cyclic nucleotide second messenger, cyclic 3′5′ adenosine monophosphate (cAMP). PDE4 inhibitors are known to have anti-inflammatory properties, but their use in the clinic has been hampered by mechanism-associated side effects that limit maximally tolerated doses. In an attempt to initiate the development of better-tolerated PDE4 inhibitors we have surveyed existing approved drugs for PDE4-inhibitory activity. With this objective, we utilised a high-throughput computational approach that identified moexipril, a well tolerated and safe angiotensin-converting enzyme (ACE) inhibitor, as a PDE4 inhibitor. Experimentally we showed that moexipril and two structurally related analogues acted in the micro molar range to inhibit PDE4 activity. Employing a FRET-based biosensor constructed from the nucleotide binding domain of the type 1 exchange protein activated by cAMP, EPAC1, we demonstrated that moexipril markedly potentiated the ability of forskolin to increase intracellular cAMP levels. Finally, we demonstrated that the PDE4 inhibitory effect of moexipril is functionally able to induce phosphorylation of the Hsp20 by cAMP dependent protein kinase A. Our data suggest that moexipril is a bona fide PDE4 inhibitor that may provide the starting point for development of novel PDE4 inhibitors with an improved therapeutic window