Binding of cell-penetrating penetratin peptides to plasma membrane vesicles correlates directly with cellular uptake

AbstractCell-penetrating peptides (CPPs) gain access to intracellular compartments mainly via endocytosis and have capacity to deliver macromolecular cargo into cells. Although the involvement of various endocytic routes has been described it is still unclear which interactions are involved in eliciting an uptake response and to what extent affinity for particular cell surface components may determine the efficiency of a particular CPP. Previous biophysical studies of the interaction between CPPs and either lipid vesicles or soluble sugar-mimics of cell surface proteoglycans, the two most commonly suggested CPP binding targets, have not allowed quantitative correlations to be established. We here explore the use of plasma membrane vesicles (PMVs) derived from cultured mammalian cells as cell surface models in biophysical experiments. Further, we examine the relationship between affinity for PMVs and uptake into live cells using the CPP penetratin and two analogs enriched in arginines and lysines respectively. We show, using centrifugation to sediment PMVs, that the amount of peptide in the pellet fraction correlates linearly with the degree of cell internalization and that the relative efficiency of all-arginine and all-lysine variants of penetratin can be ascribed to their respective cell surface affinities. Our data show differences between arginine- and lysine-rich variants of penetratin that has not been previously accounted for in studies using lipid vesicles. Our data also indicate greater differences in binding affinity to PMVs than to heparin, a commonly used cell surface proteoglycan mimic. Taken together, this suggests that the cell surface interactions of CPPs are dependent on several cell surface moieties and their molecular organization on the plasma membrane

Co-firing of biomass and other wastes in fluidised bed systems

A project on co-firing in large-scale power plants burning coal is currently funded by the European Commission. It is called COPOWER. The project involves 10 organisations from 6 countries. The project involves combustion studies over the full spectrum of equipment size, ranging from small laboratory-scale reactors and pilot plants, to investigate fundamentals and operating parameters, to proving trials on a commercial power plant in Duisburg. The power plant uses a circulating fluidized bed boiler. The results to be obtained are to be compared as function of scale-up. There are two different coals, 3 types of biomass and 2 kinds of waste materials are to be used for blending with coal for co-firing tests. The baseline values are obtained during a campaign of one month at the power station and the results are used for comparison with those to be obtained in other units of various sizes. Future tests will be implemented with the objective to achieve improvement on baseline values. The fuels to be used are already characterized. There are ongoing studies to determine reactivities of fuels and chars produced from the fuels. Reactivities are determined not only for individual fuels but also for blends to be used. Presently pilot-scale combustion tests are also undertaken to study the effect of blending coal with different types of biomass and waste materials. The potential for synergy to improve combustion is investigated. Early results will be reported in the Conference. Simultaneously, studies to verify the availability of biomass and waste materials in Portugal, Turkey and Italy have been undertaken. Techno-economic barriers for the future use of biomass and other waste materials are identified. The potential of using these materials in coal fired power stations has been assessed. The conclusions will also be reported

Effects of chirality on the intracellular localization of binuclear ruthenium(II) polypyridyl complexes

Interest in binuclear ruthenium(II) polypyridyl complexes as luminescent cellular imaging agents and for biomedical applications is increasing rapidly. We have investigated the cellular localization, uptake, and biomolecular interactions of the pure enantiomers of two structural isomers of [μ-bipb(phen)4Ru2]4+ (bipb is bis(imidazo[4,5-f]-1,10-phenanthrolin-2-yl)benzene and phen is 1,10-phenanthroline) using confocal laser scanning microscopy, emission spectroscopy, and linear dichroism. Both complexes display distinct enantiomeric differences in the staining pattern of fixed cells, which are concluded to arise from chiral discrimination in the binding to intracellular components. Uptake of complexes in live cells is efficient and nontoxic at 5 μM, and occurs through an energy-dependent mechanism. No differences in uptake are observed between the structural isomers or the enantiomers, suggesting that the interactions triggering uptake are rather insensitive to structural variations. Altogether, these findings show that the complexes investigated are promising for future applications as cellular imaging probes. In addition, linear dichroism shows that the complexes exhibit DNA-condensing properties, making them interesting as potential gene delivery vectors

3 rd i-CIPEC

Abstract: Co-combustion of sewage sludge with coal or wood as base fuels may cause high emissions of sulphur dioxide and hydrogen chlorine to the atmosphere. The conventional technique for sulphur capture in fluidised bed combustion using coal, lime addition, works well under co-combustion conditions with coal as base fuel but not with wood. The concentration of SO2 certainly plays a role, but phosphorous, originating from the sewage sludge, forms calcium phosphate that may interfere with the sulphur capture reactions normally taking place when lime is added to the bed. Lime addition to the fluidized bed during combustion of pulp&paper sludge, not containing phosphorous and with similar sulphur levels as for the sewage sludge, gives a normal sulphur capture. Adding hydrated lime to a bag filter is an alternative to lime addition to the bed that can be used when fuels with high content of phosphorous are co-combusted with wood. Hydrated lime also captures chlorine in the bag filte

The importance of SO2 and SO3 for sulphation of gaseous KCl - An experimental investigation in a biomass fired CFB boiler

This paper is based on results obtained during co-combustion of wood pellets and straw in a 12 MW circulating fluidised bed (CFB) boiler. Elemental sulphur (S) and ammonium sulphate ((NH4)(2)SO4) were used as additives to convert the alkali chlorides (mainly KCl) to less corrosive alkali sulphates. Their performance was then evaluated using several measurement tools including, IACM (on-line measurements of gaseous alkali chlorides), a low-pressure impactor (particle size distribution and chemical composition of extracted fly ash particles), and deposit probes (chemical composition in deposits collected). The importance of the presence of either SO2 or SO3 for gas phase sulphation of KCl is also discussed. Ammonium sulphate performed significantly better than elemental sulphur. A more efficient sulphation of gaseous KCl was achieved with (NH4)(2)SO4 even when the S/Cl molar ratio was less than half compared to sulphur. Thus the presence of gaseous SO3 is of greater importance than that of SO2 for the sulphation of gaseous KCl. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved

Fallstudie — Avgiftssystem fosfor och kväve för kommunala avloppsreningsverk

I denna studie undersöks effekter av ett avgiftssystem för utsläpp av kväve och fosfor från avloppsreningsverk som bygger på samma principer som det svenska NOx-systemet för förbränningsanläggningar, vilket innebär att en avgift tas ut per kg utsläppt fosfor och kväve. Pengar betalas sedan tillbaka till avloppsreningsverken utifrån en återföringsnyckel.Avgiftssystemet utvärderades i Mälarens och Mörrumsåns avrinningsområden, samt vid utvalda avloppsreningsverk. Studien baseras till största delen på kontakter med ett 20-tal kommunala avloppsreningsverk där frågor om verkens teknik och aktuella data diskuterades. Ett syfte har varit att teoretiskt jämföra effekten av avgiftssystemet vid olika avgiftsnivåer med Baltic Sea Action Plan-betinget för Sveriges havsbassänger genom att skala upp resultaten inom Norra Östersjöns vattendistrikt. Resultaten i studien talar för att en avgift på 200 kr/kg kväve med bred marginal skulle uppfylla BSAP-målet att minska belastningen på havet med 3 000 ton årligen. Kostnaden för detta skulle emellertid bli likartad ett system med generella reningskrav och denna avgiftsnivå skulle innebära stora investeringar för många reningsverk. Vid en avgift på 75 kr/kg N skulle en kvävereduktion på ca 2 100 ton kväve/år kunna nås — dvs. ca 70 % av målet. I kombination med omprövningar av tillstånd som ändå kommer att ske för vissa reningsverk, för att klara vattenförvaltningens krav på god ekologisk status i recipienterna, är sannolikt  ett system med en avgift på 75 kg/kg N  ett  kostnadseffektivt sätt att uppnå såväl BSAP som övriga miljömål. För fosfor är det troligt att man redan idag utan ytterligare åtgärder kommer att klara det uppsatta målet att minska utsläppen med minst 15 ton/år.The objective of this study was to investigate effects of a refunded emission payment system for nitrogen and phosphorus applied in municipal wastewater treatment plants. The system has been suggested by The Swedish Water & Wastewater Association and is inspired by the Swedish NOx abatement system for combustion plants where taxes are fully refunded to the polluting firms in proportion to market shares. In the investigated system for nutrients, the refunding is based on the number of persons connected to each plant. The exact refunding scheme was one of the key challenges in the project with new insights provided by discussions with potential participants. The emission payment system was evaluated in two catchments with different characteristics; the relatively dense populated catchment of Lake Mälaren and the more sparsely populated catchment area of River Mörrumsån, plus a small number of selected water treatment plants. One intention was also to theoretically compare the effect of the emission payment system with the Swedish commitment according to the Baltic Sea Action Plan (BSAP), by scaling up the results within the administrative region of Northern Baltic Proper including plants > 2 000 pe. The project also investigated how retention, i.e. reduction of the amount of nitrogen and phosphorus between the source and the sea, may affect the design of the system.  The study was largely based on contacts with around 20 municipal wastewater treatment plants, where issues about treatment technology and monitoring data were discussed. Questions regarding possible new technologies and costs of construction and operation were superficially investigated for some plants and more in depth for other plants. In this way cost-effective measures at the plants at certain payment levels were identified. The estimated reduction of nitrogen and phosphorus in an applied emission payment system were further used to scale up the results to national estimates for the Kattegat and the Baltic Proper for comparison with environmental goals and specifically with the Swedish commitment within the BSAP. An emission payment system is more likely to come into existence for nitrogen, and it was found that payment level of 200 SEK/kg N would obtain the target to reduce the annual nitrogen load to the sea by 3 000 tonnes per year (compared with 2006) with a broad margin. This reduction corresponds to the requirements on the Swedish wastewater treatment plants before 2021 related to the BSAP signed by the Swedish government. The cost for this reduction would however be similar to a system with general requirements (for all plants), and it would involve large investments for many plants. With a payment level of 75 SEK/kg N, a nitrogen reduction by 2 100 tonnes could be obtained — i.e. 70% of the target. Combining a 75 SEK/kg N payment level with renegotiations of existing regulations for selected wastewater treatment plants necessary to achieve good ecological status according to the Water Framework Directive (WFD) may be a more cost-efficient way to achieve BSAP as well as other environmental goals. For phosphorus it is likely that the established goal to reduce annual emissions by at least 15 tonnes (compared with 2006) will be achieved without further measures. For this reason, further reductions will likely be motivated by local requirements according to the WFD. With a general emission payment system a cost of around 3 000 SEK/kg P would be required to achieve significant emission reductions according to this study. There are probably advantages with an emission payment system compared with permit regulations, both regarding costs and performance. Importantly, administrative costs seem to be lower on a societal level. At the below mentioned workshop several participants question if it would even be possible to renegotiate all relevant existing permit regulations within the time frame of BSAP. In contrast, an emission payment system could be applied shortly and rapidly deliver process optimization and better use of the existing capacity in treatment plants. In addition, it is likely that the acceptance for such a system would be greater among participants than for general regulation of emissions by new requirements or renegotiations of existing permits, which is a non-trivial factor for reaching the goal. In a workshop concerning economic policy instruments arranged by IVL together with the Swedish Environmental Protection Agency and The Swedish Water & Wastewater Association in connection with this project, a principle was discussed in which an emission payment system could be designed so that the participating treatment plants may claim quantifiable measures in the recipients such as nitrogen and phosphorus uptake by cultivating mussels or tunicates

Chalmers Publication Library Gas Phase Alkali Chlorides and Deposits during Co-Combustion of Coal and Biomass Gas Phase Alkali Chlorides and Deposits during Co- Combustion of Coal and Biomass

Abstract Straw pellets have been co-fired with a bituminous coal with a high chlorine content. The tests were carried out in a 12 MW circulating fluidized bed (CFB) boiler located at Chalmers University of Technology in Sweden. The tests focused on variation of the ratio of straw to coal in combination with different feeding rates of limestone to the bed. Three test series were carried out: Lime -the fuel was a constant mixture of coal and straw pellets, with an increasing lime supply; Coal -the fuel was coal only, with an increasing lime supply. Alkalithe fuel was coal and straw pellets and constant lime supply. The fraction of straw pellets (alkali) was increased. An In-situ Alkali Chloride Monitor (IACM) was used during the tests to measure the on-line concentration of alkali chlorides and SO 2 before the convection section of the boiler. Deposit measurements were also carried out and the deposits were analysed by means of SEM-EDX. It was found that an increased fraction of straw pellets in the fuel mix results in increased level of alkali chlorides in the gas phase as well as in collected deposits. Introduction Co-combustion of biomass with coal or other primary fuels has many potential advantages: the effective emission of CO 2 is reduced by replacing a certain amount of coal with biomass, and efficient utilisation of the energy in biomass by converting it to electricity in a coal power station. There are also potential risks: some biofuels may lead to deposit formation on heat exchanger surfaces in the combustor or to bed agglomeration in a fluidised bed. Fluidised bed combustion is probably the most advantageous method available for co-combustion due to its fuel flexibility and the possibility to influence the processes of formation and destruction of emissions. There are several important factors to investigate when co-firing coal and biomass. This project focuses on the possibility of co-firing a troublesome fuel (with respect to alkali related problems) such as straw with coal. Gas phase alkali chlorides was measured by means of an In-situ Alkali Chloride Monitor (IACM) and SEM-EDX was used for analysis of collected deposit. IACM was also used as a tool for on-line judgements of the limits of co-firing in order to avoid deposit problems. The results from SEM-EDX analysis were used to support the results from IACM. The results were also discussed with respect to mechanisms that could explain the positiv

Effect of pH on Kraft Lignin Depolymerisation in Subcritical Water

Softwood kraft lignin was depolymerized using subcritical water (623 K and 25 MPa) in a continuous small pilot unit. ZrO2 and K2CO3 were used as catalysts, and phenol was used as capping agent to suppress repolymerization. The effect of pH was investigated by adding KOH in five steps to the feed. The yield of water-soluble organics increased with pH. The yield of bio-oil was also influenced by the pH and varied between 28 and 32 wt %. The char yield on the zirconia catalyst showed a minimum at pH 8.1. The yield of suspended solids was low at pH below 8.1 but increased at higher pH values. The oxygen content in the bio-oil was only 15 wt %, compared to about 26 wt % in the kraft lignin