1,979 research outputs found
On the feasibility of attribute-based encryption on Internet of Things devices
Attribute-based encryption (ABE) could be an effective cryptographic tool for the secure management of Internet of Things (IoT) devices, but its feasibility in the IoT has been under-investigated thus far. This article explores such feasibility for well-known IoT platforms, namely, Intel Galileo Gen 2, Intel Edison, Raspberry pi 1 model B, and Raspberry pi zero, and concludes that adopting ABE in the IoT is indeed feasible
Optical parametric oscillation with distributed feedback in cold atoms
There is currently a strong interest in mirrorless lasing systems, in which
the electromagnetic feedback is provided either by disorder (multiple
scattering in the gain medium) or by order (multiple Bragg reflection). These
mechanisms correspond, respectively, to random lasers and photonic crystal
lasers. The crossover regime between order and disorder, or correlated
disorder, has also been investigated with some success. Here, we report
one-dimensional photonic-crystal lasing (that is, distributed feedback lasing)
with a cold atom cloud that simultaneously provides both gain and feedback. The
atoms are trapped in a one-dimensional lattice, producing a density modulation
that creates a strong Bragg reflection with a small angle of incidence. Pumping
the atoms with auxiliary beams induces four-wave mixing, which provides
parametric gain. The combination of both ingredients generates a mirrorless
parametric oscillation with a conical output emission, the apex angle of which
is tunable with the lattice periodicity
Using honey to heal diabetic foot ulcers
Diabetic ulcers seem to be arrested in the inflammatory/proliferative stage of the healing process, allowing infection and inflammation to preclude healing. Antibiotic-resistant bacteria have become a major cause of infections, including diabetic foot infections. It is proposed here that the modern developments of an ancient and traditional treatment for wounds, dressing them with honey, provide the solution to the problem of getting diabetic ulcers to move on from the arrested state of healing. Honeys selected to have a high level of antibacterial activity have been shown to be very effective against antibiotic-resistant strains of bacteria in laboratory and clinical studies. The potent anti-inflammatory action of honey is also likely to play an important part in overcoming the impediment to healing that inflammation causes in diabetic ulcers, as is the antioxidant activity of honey. The action of honey in promotion of tissue regeneration through stimulation of angiogenesis and the growth of fibroblasts and epithelial cells, and its insulin-mimetic effect, would also be of benefit in stimulating the healing of diabetic ulcers. The availability of honey-impregnated dressings which conveniently hold honey in place on ulcers has provided a means of rapidly debriding ulcers and removing the bacterial burden so that good healing rates can be achieved with neuropathic ulcers. With ischemic ulcers, where healing cannot occur because of lack of tissue viability, these honey dressings keep the ulcers clean and prevent infection occurring
Designed Azolopyridinium Salts Block Protective Antigen Pores In Vitro and Protect Cells from Anthrax Toxin
Background:Several intracellular acting bacterial protein toxins of the AB-type, which are known to enter cells by endocytosis, are shown to produce channels. This holds true for protective antigen (PA), the binding component of the tripartite anthrax-toxin of Bacillus anthracis. Evidence has been presented that translocation of the enzymatic components of anthrax-toxin across the endosomal membrane of target cells and channel formation by the heptameric/octameric PA63 binding/translocation component are related phenomena. Chloroquine and some 4-aminoquinolones, known as potent drugs against Plasmodium falciparium infection of humans, block efficiently the PA63-channel in a dose dependent way.Methodology/Principal Findings:Here we demonstrate that related positively charged heterocyclic azolopyridinium salts block the PA63-channel in the μM range, when both, inhibitor and PA63 are added to the same side of the membrane, the cis-side, which corresponds to the lumen of acidified endosomal vesicles of target cells. Noise-analysis allowed the study of the kinetics of the plug formation by the heterocycles. In vivo experiments using J774A.1 macrophages demonstrated that the inhibitors of PA63-channel function also efficiently block intoxication of the cells by the combination lethal factor and PA63 in the same concentration range as they block the channels in vitro.Conclusions/Significance:These results strongly argue in favor of a transport of lethal factor through the PA63-channel and suggest that the heterocycles used in this study could represent attractive candidates for development of novel therapeutic strategies against anthrax. © 2013 Beitzinger et al
The developmental effects of media-ideal internalization and self-objectification processes on adolescents’ negative body-feelings, dietary restraint, and binge eating
Despite accumulated experimental evidence of the negative effects of exposure to media-idealized images, the degree to which body image, and eating related disturbances are caused by media portrayals of gendered beauty ideals remains controversial. On the basis of the most up-to-date meta-analysis of experimental studies indicating that media-idealized images have the most harmful and substantial impact on vulnerable individuals regardless of gender (i.e., “internalizers” and “self-objectifiers”), the current longitudinal study examined the direct and mediated links posited in objectification theory among media-ideal internalization, self-objectification, shame and anxiety surrounding the body and appearance, dietary restraint, and binge eating. Data collected from 685 adolescents aged between 14 and 15 at baseline (47 % males), who were interviewed and completed standardized measures annually over a 3-year period, were analyzed using a structural equation modeling approach. Results indicated that media-ideal internalization predicted later thinking and scrutinizing of one’s body from an external observer’s standpoint (or self-objectification), which then predicted later negative emotional experiences related to one’s body and appearance. In turn, these negative emotional experiences predicted subsequent dietary restraint and binge eating, and each of these core features of eating disorders influenced each other. Differences in the strength of these associations across gender were not observed, and all indirect effects were significant. The study provides valuable information about how the cultural values embodied by gendered beauty ideals negatively influence adolescents’ feelings, thoughts and behaviors regarding their own body, and on the complex processes involved in disordered eating. Practical implications are discussed
Non-Equilibrium Edge Channel Spectroscopy in the Integer Quantum Hall Regime
Heat transport has large potentialities to unveil new physics in mesoscopic
systems. A striking illustration is the integer quantum Hall regime, where the
robustness of Hall currents limits information accessible from charge
transport. Consequently, the gapless edge excitations are incompletely
understood. The effective edge states theory describes them as prototypal
one-dimensional chiral fermions - a simple picture that explains a large body
of observations and calls for quantum information experiments with quantum
point contacts in the role of beam splitters. However, it is in ostensible
disagreement with the prevailing theoretical framework that predicts, in most
situations, additional gapless edge modes. Here, we present a setup which gives
access to the energy distribution, and consequently to the energy current, in
an edge channel brought out-of-equilibrium. This provides a stringent test of
whether the additional states capture part of the injected energy. Our results
show it is not the case and thereby demonstrate regarding energy transport, the
quantum optics analogy of quantum point contacts and beam splitters. Beyond the
quantum Hall regime, this novel spectroscopy technique opens a new window for
heat transport and out-of-equilibrium experiments.Comment: 13 pages including supplementary information, Nature Physics in prin
The role of input noise in transcriptional regulation
Even under constant external conditions, the expression levels of genes
fluctuate. Much emphasis has been placed on the components of this noise that
are due to randomness in transcription and translation; here we analyze the
role of noise associated with the inputs to transcriptional regulation, the
random arrival and binding of transcription factors to their target sites along
the genome. This noise sets a fundamental physical limit to the reliability of
genetic control, and has clear signatures, but we show that these are easily
obscured by experimental limitations and even by conventional methods for
plotting the variance vs. mean expression level. We argue that simple, global
models of noise dominated by transcription and translation are inconsistent
with the embedding of gene expression in a network of regulatory interactions.
Analysis of recent experiments on transcriptional control in the early
Drosophila embryo shows that these results are quantitatively consistent with
the predicted signatures of input noise, and we discuss the experiments needed
to test the importance of input noise more generally.Comment: 11 pages, 5 figures minor correction
Determining the neurotransmitter concentration profile at active synapses
Establishing the temporal and concentration profiles of neurotransmitters during synaptic release is an essential step towards understanding the basic properties of inter-neuronal communication in the central nervous system. A variety of ingenious attempts has been made to gain insights into this process, but the general inaccessibility of central synapses, intrinsic limitations of the techniques used, and natural variety of different synaptic environments have hindered a comprehensive description of this fundamental phenomenon. Here, we describe a number of experimental and theoretical findings that has been instrumental for advancing our knowledge of various features of neurotransmitter release, as well as newly developed tools that could overcome some limits of traditional pharmacological approaches and bring new impetus to the description of the complex mechanisms of synaptic transmission
Estimation of HIV burden through Bayesian evidence synthesis
Planning, implementation and evaluation of public health policies to control
the human immunodeficiency virus (HIV) epidemic require regular monitoring of
disease burden. This includes the proportion living with HIV, whether diagnosed
or not, and the rate of new infections in the general population and in
specific risk groups and regions. Estimation of these quantities is not
straightforward: data informing them directly are not typically available, but
a wealth of indirect information from surveillance systems and ad hoc studies
can inform functions of these quantities. In this paper we show how the
estimation problem can be successfully solved through a Bayesian evidence
synthesis approach, relaxing the focus on "best available" data to which
classical methods are typically restricted. This more comprehensive and
flexible use of evidence has led to the adoption of our proposed approach as
the official method to estimate HIV prevalence in the United Kingdom since
2005
TRY plant trait database - enhanced coverage and open access
Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
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