Cooperative wrapping of nanoparticles by membrane tubes

The bioactivity of nanoparticles crucially depends on their ability to cross biomembranes. Recent simulations indicate the cooperative wrapping and internalization of spherical nanoparticles in tubular membrane structures. In this article, we systematically investigate the energy gain of this cooperative wrapping by minimizing the energies of the rotationally symmetric shapes of the membrane tubes and of membrane segments wrapping single particles. We find that the energy gain for the cooperative wrapping of nanoparticles in membrane tubes relative to their individual wrapping as single particles strongly depends on the ratio of the particle radius and the range of the particle-membrane adhesion potential. For a potential range of the order of one nanometer, the cooperative wrapping in tubes is highly favorable for particles with a radius of tens of nanometers and intermediate adhesion energies, but not for particles that are significantly larger.Comment: 9 pages, 7 figures; to appear in Soft Matte

Characterization of the LATERAL SUPPRESSOR Promoter and the New Regulator of Axillary Meristem Formation ENHANCER OF LATERAL SUPPRESSOR 5

Aerial architecture of flowering plants is largely based on the activities of the shoot apical meristem and axillary meristems (AM), which are initiated in the axils of leaves. The LATERAL SUPPRESSOR (LAS) loss-of-function mutant is characterized by a lack AM development during the vegetative growth phase, identifying LAS as a key regulator of this process. LAS is expressed in a very specific band-shaped domain at the adaxial side of leaf primordia, the site of later formation of AMs. In order to understand how this specific expression pattern is established, and to be able to subsequently address the question which factors control LAS, the LAS promoter was analyzed in detail in this work. Complementation of the las-4 phenotype with various promoter deletion constructs revealed that less than 117 bp 5' of the transcription start are necessary for gene function. However, the ability to complement is lost when constructs harbor less than 3547 bp of 3' sequences. The importance of the 3' region is emphasized by results showing that complementation is still achieved if the 5' promoter is replaced by a minimal 35S promoter or a PISTILLATA (PI) promoter fragment, which does not confer expression in the apex. In both cases visualization of expression profiles using promoter GUS constructs showed specific expression in axils of leaves and flowers, alike the endogenous LAS promoter activity. In summary an LAS 3' promoter element, extending from bp 3239 to 3547 behind the ORF, was found to be necessary for complementation. We speculate that it is this element, which causes the highly specific LAS expression pattern. A previous las-4 second site modifier screen led to the identification of the new regulator of AM development ENHANCER OF LATERAL SUPPRESSOR 5 (EOL5). The eol5 las-4 double mutant was identified owing to the lack of AM formation in cauline leaf axils. Additionally, eol5 las-4 plants could be shown to exhibit leaf fusions and defects in meristem maintenance and floral primordia development. The gene underlying the eol5 mutation could be identified by map based cloning as CZS, a putative histone methyl transferase, previously shown to be involved in the epigenetic regulation of FLOWERING LOCUS C (FLC) and displays a mild delay of flowering. Complementation with an endogenous pCZS::CZS construct led to a recovery of the ability to form axillary shoots in cauline leaf axils, likewise an allelism test showed that the T-DNA insertion alleles czs-1 and czs-2 are allelic to eol5. However, the single mutant phenotype of eol5 is more pronounced, leading to a lack of AM formation in most rosette leaf axils, whereas czs-1 and czs-2 plants only exhibited few barren axils in the lower rosette. Accordingly, the delay of flowering observed in long day conditions was most distinct in eol5 plants. To address the question which genes are regulated by CZS, the expression of various candidates was compared between mutants and wild-type by real-time PCR. FLC could be shown to be upregulated in czs mutants. Analysis of FRI FLC plants, which strongly express FLC, revealed side shoot development defects, suggesting that FLC is involved in the process of AM formation. This indicates that similar mechanisms regulate lateral meristem development and flowering, thus the AM initiation defects observed in czs mutants are likely to be caused by the upregulation of FLC

Corruption\u27s Hold on the Economy: An Examination of the Causes of Economic Development

This study focuses on the relationship between political corruption and economic development through a cross-national survey of twenty-three of the twenty-five European Union Member States. This study was conducted in order to expand on the research conducted by Margaret Goodman and Nathaniel Leff. The survey examined the effect of political corruption on six dependent variables that represent economic development: gross domestic product per capita, unemployment rate, education, fertility rate, infant mortality rate, and government debt. Of the six, GDP, unemployment and fertility were shown to be significant. The findings suggest that corruption index increase coupled with a job creation program caused decreases in unemployment and increases in GDP

Growing A Business: An Examination of Issues Involved with Business Expansion

ABC inc is a North Dakota company with an eighteen-year history of success in the engineering consulting and technology products and services. ABCinc faces an opportunity to expand its reach into a new geographical area in the southeast United States. A marketing and business plan have been created for this expansion oppotiunity, which is a necessary step to ensure that there is a roadmap to follow, that goals and objectives are defined, and that managers and employees are focuses on a common plan The opportunity offers ABCinc the potential for financial growth, diversification into new customers and industries, and the opportunity of increased revenues and profits. The recommendation based on the issues examined in this report is to proceed with the opportunity to expand, with continuous monitoring and comparison of actual results with projection

Master of Science

thesisThe purpose of this study is to examine how representation format and task instructions impact student learning in a science domain. Learning outcomes were assessed via measures of mental model, declarative knowledge, and knowledge inference. Students were asked to use one of two forms of representation, either drawing or writing, during study of a science text. Further, instructions (summarize vs. explain) were varied to determine if students' intended use of the presentation influenced learning. Thus, this study used a 2 (drawing vs. writing) X 2 (summarize vs. explain) between-subjects design. Drawing was hypothesized to require integration across learning materials regardless of task instructions, because drawings (by definition) require learners to integrate new information into a visual representation. Learning outcomes associated with writing were hypothesized to depend upon task instructions: when asked to summarize, writing should result in reproduction of text; when asked t