Charge-induced conformational changes of dendrimers

We study the effect of chargeable monomers on the conformation of dendrimers of low generation by computer simulations, employing bare Coulomb interactions. The presence of the latter leads to an increase in size of the dendrimer due to a combined effect of electrostatic repulsion and the presence of counterions within the dendrimer, and also enhances a shell-like structure for the monomers of different generations. In the resulting structures the bond-length between monomers, especially near the center, will increase to facilitate a more effective usage of space in the outer-regions of the dendrimer.Comment: 7 pages, 12 figure

Indigenous knowledges and development: a postcolonial caution

As a result of the failure of formal top-down development, there has recently been increased interest in the possibilities of drawing upon the indigenous knowledges of those in the communities involved, in an attempt to produce more effective development strategies. The concept of indigenous knowledge calls for the inclusion of local voices and priorities, and promises empowerment through ownership of the process. However, there has been little critical examination of the ways in which indigenous knowledges have been included in the development process. Drawing upon postcolonial theory, this article suggests that indigenous knowledges are often drawn into development by both theorists and development institutions in a very limited way, failing to engage with other ways of perceiving development, and thus missing the possibility of devising more challenging alternatives

Interaction of cylindrical polymer brushes in dilute and semi-dilute solution

We present a systematic study of flexible cylindrical brush-shaped macromolecules in a good solvent by small-angle neutron scattering (SANS), static light scattering (SLS), and by dynamic light scattering (DLS) in dilute and semi-dilute solution. The SLS and SANS data extrapolated to infinite dilution lead to the shape of the polymer that can be modeled in terms of a worm-like chain with a contour length of 380 nm and a persistence length of 17.5 nm. SANS data taken at higher polymer concentration were evaluated by using the polymer reference interaction site model (PRISM). We find that the persistence length reduce from 17.5 nm at infinite dilution to 5.3 nm at the highest concentration (volume fraction 0.038). This is comparable with the decrease of the persistence length in semi-dilute concentration predicted theoretically for polyelectrolytes. This finding reveals a softening of stiffness of the polymer brushes caused by their mutual interaction

From Mexico to Beijing: "Women in Development" Twenty Five Years On

During the past twenty five years the Women in Development (WID)approach has become an increasingly important issue in the literature on Third World development. WID issues and related activities have now been incorporated into the aid practice of most development agencies. This paper critically analyses the diverse and conflicting ideologies that have emerged in the WID literature since the early seventies

Heat and moisture exchangers (HMEs) and heated humidifiers (HHs) in adult critically ill patients: a systematic review, meta-analysis and meta-regression of randomized controlled trials

The aims of this systematic review and meta-analysis of randomized controlled trials are to evaluate the effects of active heated humidifiers (HHs) and moisture exchangers (HMEs) in preventing artificial airway occlusion and pneumonia, and on mortality in adult critically ill patients. In addition, we planned to perform a meta-regression analysis to evaluate the relationship between the incidence of artificial airway occlusion, pneumonia and mortality and clinical features of adult critically ill patients

The Photosynthetic Apparatus and Its Regulation in the Aerobic Gammaproteobacterium Congregibacter litoralis gen. nov., sp. nov

BACKGROUND: There is accumulating evidence that in some marine environments aerobic bacteriochlorophyll a-producing bacteria represent a significant part of the microbial population. The interaction of photosynthesis and carbon metabolism in these interesting bacteria is still largely unknown and requires further investigation in order to estimate their contribution to the marine carbon cycle. METHODOLOGY/PRINCIPAL FINDINGS: Here, we analyzed the structure, composition and regulation of the photosynthetic apparatus in the obligately aerobic marine gammaproteobacterium KT71(T). Photoheterotrophically grown cells were characterized by a poorly developed lamellar intracytoplasmic membrane system, a type 1 light-harvesting antenna complex and a photosynthetic reaction center associated with a tetraheme cytochrome c. The only photosynthetic pigments produced were bacteriochlorophyll a and spirilloxanthin. Under semiaerobic conditions KT71(T) cells expressing a photosynthetic apparatus showed a light-dependent increase of growth yield in the range of 1.3-2.5 fold. The expression level of the photosynthetic apparatus depended largely on the utilized substrate, the intermediary carbon metabolism and oxygen tension. In addition, pigment synthesis was strongly influenced by light, with blue light exerting the most significant effect, implicating that proteins containing a BLUF domain may be involved in regulation of the photosynthetic apparatus. Several phenotypic traits in KT71(T) could be identified that correlated with the assumed redox state of growing cells and thus could be used to monitor the cellular redox state under various incubation conditions. CONCLUSIONS/SIGNIFICANCE: In a hypothetical model that explains the regulation of the photosynthetic apparatus in strain KT71(T) we propose that the expression of photosynthesis genes depends on the cellular redox state and is maximal under conditions that allow a balanced membrane redox state. So far, bacteria capable of an obligately aerobic, photosynthetic metabolism constitute a unique phenotype within the class Gammaproteobacteria, so that it is justified to propose a new genus and species, Congregibacter litoralis gen. nov, sp. nov., represented by the type strain KT71(T) ( = DSM 17192(T) = NBRC 104960(T))