DNA alters the bilayer structure of cationic lipid diC14-amidine: A spin label study

Cationic lipids-DNA complexes (lipoplexes) have been used for delivery of nucleic acids into cells in vitro and in vivo. Despite the fact that, over the last decade, significant progress in the understanding of the cellular pathways and mechanisms involved in lipoplexes-mediated gene transfection have been achieved, a convincing relationship between the structure of lipoplexes and their in vivo and in vitro transfection activity is still missing. How does DNA affect the lipid packing and what are the consequences for transfection efficiency is the point we want to address here. We investigated the bilayer organization in cationic liposomes by electron spin resonance (ESR). Phospholipids spin labeled at the 5th and 16th carbon atoms were incorporated into the DNA/diC14-amidine complex. Our data demonstrate that electrostatic interactions involved in the formation of DNA-cationic lipid complex modify the packing of the cationic lipid membrane. DNA rigidifies the amidine fluid bilayer and fluidizes the amidine rigid bilayer just below the gel-fluid transition temperature. These effects were not observed with single nucleotides and are clearly related to the repetitive charged motif present in the DNA chain and not to a charge-charge interaction. These modifications of the initial lipid packing of the cationic lipid may reorient its cellular pathway towards different routes. A better knowledge of the cationic lipid packing before and after interaction with DNA may therefore contribute to the design of lipoplexes capable to reach specific cellular targets. (c) 2009 Elsevier B.V. All rights reserved.

Multiple stages of detergent-erythrocyte membrane interaction-A spin label study

The various stages of the interaction between the detergent Triton X-100 (TTX-100) and membranes of whole red blood cells (RBC) were investigated in a broad range of detergent concentrations. The interaction was monitored by RBC hemolysis-assessed by release of intracellular hemoglobin (Hb) and inorganic phosphate- and by analysis of EPR spectra of a fatty acid spin probe intercalated in whole RBC suspensions, as well as pellets and supernatants obtained upon centrifugation of detergent-treated cells. Hemolysis finished at ca. 0.9 mM TTX-100. Spectral analysis and calculation of order parameters (S) indicated that a complex sequence of events takes place, and allowed the characterization of various structures formed in the different stages of detergent-membrane interaction. Upon reaching the end of cell lysis, essentially no pellet was detected, the remaining EPR signal being found almost entirely in the supernatants. Calculated order parameters revealed that whole RBC suspensions, pellets, and supernatants possessed a similar degree of molecular packing, which decreased to a small extent up to 2.5 mM detergent. Between 3.2 and 10 mM TTX-100, a steep decrease in S was observed for both whole RBC suspensions and supernatants. Above 10 mM detergent, S decreased in a less pronounced manner and the EPR spectra approached that of pure TTX-100 micelles. The data were interpreted in terms of the following events: at the lower detergent concentrations, an increase in membrane permeability occurs: the end of hemolysis coincides with the lack of pellet upon centrifugation. Up to 2.5 mM TTX-100 the supernatants consist of a (very likely) heterogeneous population of membrane fragments with molecular packing similar to that of whole cells. As the detergent concentration increases, mixed micelles are formed containing lipid and/or protein, approaching the packing found in pure TTX-100 micelles. This analysis is in agreement with the models proposed by Lasch (Biochim. Biophys Acta 1241 (1995) 269-292) and by Le Maire and coworkers (Biochim. Biophys. Acta 1508 (2000) 86-111). (C) 2010 Elsevier B.V. All rights reserved.

Under flow impedimetric measurements using magnetic particles for label-free detection affinity target

The necessity to adapt sensors based on electrochemical techniques for high throughput analysis control increases the interest to develop new analytical systems able to perform measurements under buffer now. In this report we explored the possibility of employing a new system to make impedimetric measurements to detect the interaction between proteins and small molecules. The well-known biotin-streptavidin interaction was adopted to evaluate the proposed assembly. This system allows us to perform experiments under flow. Magnetic beads functionalized with streptavidin were used and first characterized using AFM and FTIR. Non-faradic impedance spectroscopy allowed the detection of the biotin-streptavidin interaction. Using our new system and under a flow of PBS buffer, 5 10-5 M of biotin was detected with a stable signal. (c) 2007 Elsevier B.V. All rights reserved.

Filmljudets funktioner i krigsfilm : En audio-visuell analys av Apocalypse Now och Saving Private Ryan

I denna uppsats har filmljudet i krigsfilmerna Apocalypse Now och Saving Private Ryan undersökts. Detta har gjorts för att försöka bidra med ökad förståelse för filmljudets användningsområde och funktioner, främst för filmerna i fråga, men även för krigsfilm rent generellt. Filmljud i denna kontext omfattar allt det ljud som finns i film, men utesluter dock all ickediegetisk musik. Båda filmerna har undersökts genom en audio-visuell analys. En sådan analys görs genom att detaljgranska båda filmernas ljud- och bildinnehåll var för sig, för att slutligen undersöka samma filmsekvens som helhet då ljudet och bilden satts ihop igen. Den audio-visuella analysmetod som nyttjats i uppsatsen är Michel Chions metod, Masking. De 30 minuter film som analyserades placerades sedan i olika filmljudzoner, där respektive filmljudzons ljudinnehåll bland annat visade vilka främsta huvudfunktioner somfilmljudet hade i dessa filmer. Dessa funktioner är till för att bibehålla åskådarens fokus och intresse, att skapa närhet till rollkaraktärerna, samt att tillföra en hög känsla av realism och närvaro. Intentionerna med filmljudet verkade vara att flytta åskådaren in i filmens verklighet, att låta åskådaren bli ett med filmen. Att återspegla denna känsla av realism, närvaro, fokus samt intresse, visade sig också vara de intentioner som funnits redan i de båda filmernas förproduktionsstadier. Detta bevisar att de lyckats åstadkomma det de eftersträvat. Men om filmljudet använts på samma sätt eller innehar samma funktioner i krigsfilm rent genrellt går inte att säga.I have for this bachelor’s thesis examined the movie sound of the classic warfare movies Apocalypse Now and Saving Private Ryan. This is an attempt to contribute to a more profound comprehension of the appliance and importance of movie sound. In this context movie sound implies all kinds of sounds within the movies, accept from non-diegetic music. These two movies have been examined by an audio-visual analysis. It's done by auditing the sound and picture content separately, and then combined to audit the same sequence as a whole. Michel Chion, which is the founder of this analysis, calls this method Masking. The sound in this 30 minute sequence was then divided into different zones, where every zone represented a certain main function. These functions are provided to create a stronger connection to the characters, sustain the viewers interest and bring a sense of realism and presence. It seems though the intention with the movies sound is to bring the viewers to the scene in hand, and let it become their reality. To mirror this sense of realism, presence, focus and interest, proves to be the intention from an early stage of the production. This bachelor’s thesis demonstrates a success in their endeavours. Although it can’t confirm whether the movie sound have been utilized in the same manner or if they posess the same functions to warefare movies in general.

Effectiveness of artemether-lumefantrine provided by community health workers in under-five children with uncomplicated malaria in rural Tanzania : an open label prospective study

Background: Home-management of malaria (HMM) strategy improves early access of anti-malarial medicines to high-risk groups in remote areas of sub-Saharan Africa. However, limited data are available on the effectiveness of using artemisinin-based combination therapy (ACT) within the HMM strategy. The aim of this study was to assess the effectiveness of artemether-lumefantrine (AL), presently the most favoured ACT in Africa, in under-five children with uncomplicated Plasmodium falciparum malaria in Tanzania, when provided by community health workers (CHWs) and administered unsupervised by parents or guardians at home. Methods: An open label, single arm prospective study was conducted in two rural villages with high malaria transmission in Kibaha District, Tanzania. Children presenting to CHWs with uncomplicated fever and a positive rapid malaria diagnostic test (RDT) were provisionally enrolled and provided AL for unsupervised treatment at home. Patients with microscopy confirmed P. falciparum parasitaemia were definitely enrolled and reviewed weekly by the CHWs during 42 days. Primary outcome measure was PCR corrected parasitological cure rate by day 42, as estimated by Kaplan-Meier survival analysis. This trial is registered with ClinicalTrials.gov, number NCT00454961. Results: A total of 244 febrile children were enrolled between March-August 2007. Two patients were lost to follow up on day 14, and one patient withdrew consent on day 21. Some 141/241 (58.5%) patients had recurrent infection during follow-up, of whom 14 had recrudescence. The PCR corrected cure rate by day 42 was 93.0% (95% CI 88.3%-95.9%). The median lumefantrine concentration was statistically significantly lower in patients with recrudescence (97 ng/mL [IQR 0-234]; n = 10) compared with reinfections (205 ng/mL [114-390]; n = 92), or no parasite reappearance (217 [121-374] ng/mL; n = 70; p <= 0.046). Conclusions: Provision of AL by CHWs for unsupervised malaria treatment at home was highly effective, which provides evidence base for scaling-up implementation of HMM with AL in Tanzania.

Globalization, Agency, and Institutional Innovation: The Rise of Public-Private Partnerships in Global Governance

Public and private actors increasingly cooperate in global governance, a realm previously reserved for states and intergovernmental organizations (IOs). This trend raises fascinating theoretical questions. What explains the rise in public-private institutions and their role in international politics? Who leads such institutional innovation and why? To address the questions, this paper develops a theory of the political demand and supply of public-private institutions and specifies the conditions under which IOs and non-state actors would cooperate, and states would support this public-private cooperation. The observable implications of the theoretical argument are evaluated against the broad trends in public-private cooperation and in a statistical analysis of the significance of demand and supply-side incentives in public-private cooperation for sustainable development. The study shows that public-private institutions do not simply fill governance gaps opened by globalization, but cluster in narrower areas of cooperation, where the strategic interests of IOs, states, and transnational actors intersect.

Soft money : private foundations of party politics

In the area of campaign financing in federal elections, one of the most controversial issues is that of soft money. Soft money refers to those funds raised by the national party organizations for use on various grassroots and party-building activities. but which are not subject to the restraints of federal campaign finance law. Critics contend that these party-building activitie, such as generic television advertising, voter registration and get-out-the vote drives, provide ancillary benefits to federal candidates and should, therefore, be subject to federal contribution and expenditure limits. Critics further argue that because these funds are not subject to federal law and do benefit federal candidates, the national parties raise monies in amounts and from sources, such as corporations and unions, that are prohibited under federal law. Efforts to gain a better understanding of soft money have been hampered by a lack of data, as the national parties were not required to disclose their soft money receipts and transactions until 1991. The purpose of this study is to analyze data recently made available in an attempt to add the import of empirical evidence to the debate over soft money. The nature, size and timing of soft money contributions are investigated and national party soft money disbursements are examined. The findings suggest that any attempts to reform the soft money system must first consider its compensatory benefits. Most prominently, this includes the extent to which soft money has promoted the resurgence of the national party organizations in the context of election politics.

Assessing Merit Aid and Need-Based Aid At Private Institutions

Institutions provide students with full tuition merit awards through formal scholarship programs for outstanding performance in academics, leadership, community service, and athletics. This brief outlines how institutions fund and utilize merit to increase retention rates, particularly for minority and first generation students.

Abstract types and distributions in independent private value auctions

In this note, in an independent private values auction framework, I discuss the relationship between the set of types and the distribution of types. I show that any set of types, finite dimensional or not, can be extended to a larger set of types preserving incentive compatibility constraints, expected revenue and bidder’s expected utilities. Thus for example we may convexify a set of types making our model amenable to the large body of theory in economics and mathematics that relies on convexity assumptions. An interesting application of this extension procedure is to show that although revenue equivalence is not valid in general if the set of types is not convex these mechanism have underlying distinct allocation mechanism in the extension. Thus we recover in these situations the revenue equivalence.

The private memory of aggregate shocks

Em economias caracterizadas por choques agregados e privados, mostramos que a alocação ótima restrita pode depender de forma não-trivial dos choques agregados. Usando versões dos modelos de Atkeson e Lucas (1992) e Mirrlees (1971) de dois períodos, é mostrado que a alocação ótima apresenta memória com relação aos choques agregados mesmo eles sendo i.i.d. e independentes dos choques individuais, quando esses últimos choques não são totalmente persistentes. O fato de os choques terem efeitos persistentes na alocação mesmo sendo informação pública, foi primeiramente apresentado em Phelan (1994). Nossas simulações numéricas indicam que esse não é um resultado pontual: existe uma relação contínua entre persistência de tipos privados e memória do choque agregado.