105 research outputs found
Copper-based water repellent and antibacterial coatings by aerosol assisted chemical vapour deposition
The adhesion and proliferation of bacteria on solid surfaces presents a major challenge in both healthcare and industrial applications. In response to this problem, an effective and simple method is reported to fabricate superhydrophobic antibacterial copper coated polymer films via aerosol assisted chemical vapor deposition (AACVD). The material is characterized using a range of techniques including electron microscopy, water contact angle measurement and elemental mapping. The antibacterial activity of the modified film is tested against the Gram-negative bacterium, Escherichia coli, and the Gram-positive bacterium, Staphylococcus aureus and the film shows highly significant antibacterial activity against both bacteria (>4 log reduction in bacterial numbers) in 15 min and 60 min, respectively. In addition, all the CVD modified samples results in a significant reduction in bacterial cell adhesion compared to the control materials. Thus, we report a new film type that has dual mode of action-the superhydrophobicity helps limit cell adhesion combined with a cytotoxic copper induced bacteria kill
Qualia: The Geometry of Integrated Information
According to the integrated information theory, the quantity of consciousness is
the amount of integrated information generated by a complex of elements, and the
quality of experience is specified by the informational relationships it
generates. This paper outlines a framework for characterizing the informational
relationships generated by such systems. Qualia space (Q) is a space having an
axis for each possible state (activity pattern) of a complex. Within Q, each
submechanism specifies a point corresponding to a repertoire of system states.
Arrows between repertoires in Q define informational relationships. Together,
these arrows specify a quale—a shape that completely and univocally
characterizes the quality of a conscious experience. Φ— the
height of this shape—is the quantity of consciousness associated with
the experience. Entanglement measures how irreducible informational
relationships are to their component relationships, specifying concepts and
modes. Several corollaries follow from these premises. The quale is determined
by both the mechanism and state of the system. Thus, two different systems
having identical activity patterns may generate different qualia. Conversely,
the same quale may be generated by two systems that differ in both activity and
connectivity. Both active and inactive elements specify a quale, but elements
that are inactivated do not. Also, the activation of an element affects
experience by changing the shape of the quale. The subdivision of experience
into modalities and submodalities corresponds to subshapes in Q. In principle,
different aspects of experience may be classified as different shapes in Q, and
the similarity between experiences reduces to similarities between shapes.
Finally, specific qualities, such as the “redness” of red,
while generated by a local mechanism, cannot be reduced to it, but require
considering the entire quale. Ultimately, the present framework may offer a
principled way for translating qualitative properties of experience into
mathematics
Manipulation of Pre-Target Activity on the Right Frontal Eye Field Enhances Conscious Visual Perception in Humans
The right Frontal Eye Field (FEF) is a region of the human brain, which has been consistently involved in visuo-spatial attention and access to consciousness. Nonetheless, the extent of this cortical site’s ability to influence specific aspects of visual performance remains debated. We hereby manipulated pre-target activity on the right FEF and explored its influence on the detection and categorization of low-contrast near-threshold visual stimuli. Our data show that pre-target frontal neurostimulation has the potential when used alone to induce enhancements of conscious visual detection. More interestingly, when FEF stimulation was combined with visuo-spatial cues, improvements remained present only for trials in which the cue correctly predicted the location of the subsequent target. Our data provide evidence for the causal role of the right FEF pre-target activity in the modulation of human conscious vision and reveal the dependence of such neurostimulatory effects on the state of activity set up by cue validity in the dorsal attentional orienting network
Mapping Human Whole-Brain Structural Networks with Diffusion MRI
Understanding the large-scale structural network formed by neurons is a major challenge in system neuroscience. A detailed connectivity map covering the entire brain would therefore be of great value. Based on diffusion MRI, we propose an efficient methodology to generate large, comprehensive and individual white matter connectional datasets of the living or dead, human or animal brain. This non-invasive tool enables us to study the basic and potentially complex network properties of the entire brain. For two human subjects we find that their individual brain networks have an exponential node degree distribution and that their global organization is in the form of a small world
Stable, Precise, and Reproducible Patterning of Bicoid and Hunchback Molecules in the Early Drosophila Embryo
Precise patterning of morphogen molecules and their accurate reading out are of key importance in embryonic development. Recent experiments have visualized distributions of proteins in developing embryos and shown that the gradient of concentration of Bicoid morphogen in Drosophila embryos is established rapidly after fertilization and remains stable through syncytial mitoses. This stable Bicoid gradient is read out in a precise way to distribute Hunchback with small fluctuations in each embryo and in a reproducible way, with small embryo-to-embryo fluctuation. The mechanisms of such stable, precise, and reproducible patterning through noisy cellular processes, however, still remain mysterious. To address these issues, here we develop the one- and three-dimensional stochastic models of the early Drosophila embryo. The simulated results show that the fluctuation in expression of the hunchback gene is dominated by the random arrival of Bicoid at the hunchback enhancer. Slow diffusion of Hunchback protein, however, averages out this intense fluctuation, leading to the precise patterning of distribution of Hunchback without loss of sharpness of the boundary of its distribution. The coordinated rates of diffusion and transport of input Bicoid and output Hunchback play decisive roles in suppressing fluctuations arising from the dynamical structure change in embryos and those arising from the random diffusion of molecules, and give rise to the stable, precise, and reproducible patterning of Bicoid and Hunchback distributions
The importance of thermodynamics for molecular systems, and the importance of molecular systems for thermodynamics
The human keratins: biology and pathology
The keratins are the typical intermediate filament proteins of epithelia, showing an outstanding degree of molecular diversity. Heteropolymeric filaments are formed by pairing of type I and type II molecules. In humans 54 functional keratin genes exist. They are expressed in highly specific patterns related to the epithelial type and stage of cellular differentiation. About half of all keratins—including numerous keratins characterized only recently—are restricted to the various compartments of hair follicles. As part of the epithelial cytoskeleton, keratins are important for the mechanical stability and integrity of epithelial cells and tissues. Moreover, some keratins also have regulatory functions and are involved in intracellular signaling pathways, e.g. protection from stress, wound healing, and apoptosis. Applying the new consensus nomenclature, this article summarizes, for all human keratins, their cell type and tissue distribution and their functional significance in relation to transgenic mouse models and human hereditary keratin diseases. Furthermore, since keratins also exhibit characteristic expression patterns in human tumors, several of them (notably K5, K7, K8/K18, K19, and K20) have great importance in immunohistochemical tumor diagnosis of carcinomas, in particular of unclear metastases and in precise classification and subtyping. Future research might open further fields of clinical application for this remarkable protein family
Variation in egg and clutch size of the Black Redstart (Phoenicurus ochruros) at the northeastern edge of the Qinghai-Tibetan Plateau
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