Cationic liposome-DNA complexes: from liquid crystal science to gene delivery applications

At present, there is an unprecedented level of interest in the properties and structures of complexes consisting of DNA mixed with oppositely charged cationic liposomes (CLs). The interest arises because the complexes mimic natural viruses as chemical carriers of DNA into cells in worldwide human gene therapy clinical trials. However, since our understanding of the mechanisms of action of CL-DNA complexes interacting with cells remains poor, significant additional insights and discoveries will be required before the development of efficient chemical carriers suitable for long-term therapeutic applications. Recent studies describe synchrotron X-ray diffraction, which has revealed the liquid crystalline nature of CL-DNA complexes, and three-dimensional laser-scanning confocal microscopy, which reveals CL-DNA pathways and interactions with cells. The importance of the liquid crystalline structures in biological function is revealed in the application of these modern techniques in combination with functional transfection efficiency measurements, which shows that the mechanism of gene release from complexes in the cell cytoplasm is dependent on their precise liquid crystalline nature and the physical and chemical parameters (for example, the membrane charge density) of the complexes. In [section sign] 5, we describe some recent new results aimed at developing bionanotube vectors for gene delivery.     

Experiential learning of clinical skills by beginning nursing students: "coaching" project by fourth-year student interns

Cutaneous larva migrans is the result of infestation of human skin by helminth larvae, which burrow through the epidermis. This route of infestation makes the foot a typical site for origination of this infection. Children, who frequently play barefoot in locations where the most common of the helminth larvae, the dog and cat hookworms, are endemic, are at particular risk for this disorder. This article reviews the differential diagnosis of cutaneous larva migrans and current concepts in management. Two cases of related children who presented to their pediatricians with this condition are reported.     

The Visual Looming Navigation Cue: A Unified Approach

Visual looming is related to an increasing projected size of an object on a viewer's retina as the relative distance between the viewer and the object decreases. It is an indication for threat that may be used along with visual fixation to accomplish navigation tasks. This paper defines visual looming as the time derivative of the relative distance (range) between the observer and the object divided by the relative distance itself. It introduces a unified approach to visual looming by showing how visual looming can be calculated from the relative temporal change in the following attributes of a 2D image sequence: (i) image area, (ii) image brightness, (iii) texture density in the image, and (iv) image blur. It is shown that a closed-form unified expression can be adopted in all these methods. Experimental results illustrate how the measured values of looming are related to the actual values. Finally, looming is used in the sense of a threat of collision, along with visual fixation, to navigate in an unknown environment.     

MRZ code extraction from visa and passport documents using convolutional neural networks

International Journal on Document Analysis and Recognition (IJDAR) - Detecting and extracting information from the machine-readable zone (MRZ) on passports and visas is becoming increasingly...     

The need and ability to achieve cognitive structuring: Individual differences that moderate the effect of stress on information processing.

The authors examined the hypothesis that the interaction between the need for cognitive structure (NCS) and the ability to achieve cognitive structure (AACS) moderates the effect of stress on information processing. NCS is the preference for using cognitive structuring, as opposed to piecemeal processes, as a means to achieve certainty. AACS is the extent to which individuals are able to apply information processes that are consistent with their levels of NCS. The hypothesis was validated in 4 studies, which showed that stress increased high-AACS participants' use of cognitive structuring if they had high NCS and reduced it if they had low NCS. An opposite effect was found for low-AACS participants. The implications of these results for the understanding of the mechanisms responsible for the effect of stress on information processing are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motives for helping behavior: Kibbutz and city children in kindergarten and school.

Studied the motives for helping expressed by 80 children 4–5? and 7–8? yrs of age. Half of each age group were from a kibbutz and half from a city. Half of each group were boys, half girls. Ss were presented with 3 pictures depicting 3 situations in which one child had an opportunity to help. They were asked whether the child in the picture would help and if so, what the child's motive would be for such an action. They were also asked questions regarding motives for helping behavior in general. Three hypotheses were stated: (1) Older Ss would express higher-level motives for helping than younger Ss. (2) Kibbutz Ss would express higher-level motives than city Ss. (3) Girls would express higher-level motives than boys. Only the 1st hypothesis was confirmed. No differences were found between kibbutz and city Ss or between boys and girls. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tilted cellulose arrangement as a novel mechanism for hygroscopic coiling in the stork's bill awn

The sessile nature of plants demands the development of seed-dispersal mechanisms to establish new growing loci. Dispersal strategies of many species involve drying of the dispersal unit, which induces directed contraction and movement based on changing environmental humidity. The majority of researched hygroscopic dispersal mechanisms are based on a bilayered structure. Here, we investigate the motility of the stork''s bill (Erodium) seeds that relies on the tightening and loosening of a helical awn to propel itself across the surface into a safe germination place. We show that this movement is based on a specialized single layer consisting of a mechanically uniform tissue. A cell wall structure with cellulose microfibrils arranged in an unusually tilted helix causes each cell to spiral. These cells generate a macroscopic coil by spiralling collectively. A simple model made from a thread embedded in an isotropic foam matrix shows that this cellulose arrangement is indeed sufficient to induce the spiralling of the cells.     

Linear programming-based algorithms for the minimum makespan high multiplicity jobshop problem

We study a generalized version of the minimum makespan jobshop problem in which multiple instances of each job are to be processed. The system starts with specified inventory levels in all buffers and finishes with some desired inventory levels of the buffers at the end of the planning horizon. A schedule that minimizes the completion time of all the operations is sought. We develop a polynomial time asymptotic approximation procedure for the problem. That is, the ratio between the value of the delivered solution and the optimal one converge into one, as the multiplicity of the problem increases. Our algorithm uses the solution of the linear relaxation of a time-indexed Mixed-Integer formulation of the problem. In addition, a heuristic method inspired by this approximation algorithm is presented and is numerically shown to out-perform known methods for a large set of standard test problems of moderate job multiplicity.