310 research outputs found
Inhibition of Bacterial Growth and Biofilm Production by Metabolites from Hypericum spp
Biofilm embedded bacterial pathogens such as Staphylococcus spp., Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii are difficult to eradicate and are major sources of bacterial infections. New drugs are needed to combat these pathogens. Hypericum is a plant genus that contains species known to have antimicrobial properties. However, the specific metabolites responsible for the antimicrobial properties are not entirely known, nor have most compounds been tested as inhibitors of biofilm development. The investigation presented here tested seven secondary metabolites isolated from the species Hypericum densiflorum, Hypericum ellipticum, Hypericum prolificum and Hypericum punctatum as inhibitors of bacterial growth and biofilm production. Assays were conducted against Staphylococcus epidermidis, Staphylococcus aureus, clinical methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii. Five of the seven metabolites demonstrated growth inhibition against the Gram-positive bacteria with minimum inhibitory concentrations (MIC) ranging from 1.95 ”g/mL to 7.81 ”g/mL. Four of the metabolites inhibited biofilm production by certain Gram-positive strains at sub-MIC concentrations
Electromagnetic field correlations near a surface with a nonlocal optical response
The coherence length of the thermal electromagnetic field near a planar
surface has a minimum value related to the nonlocal dielectric response of the
material. We perform two model calculations of the electric energy density and
the field's degree of spatial coherence. Above a polar crystal, the lattice
constant gives the minimum coherence length. It also gives the upper limit to
the near field energy density, cutting off its divergence. Near an
electron plasma described by the semiclassical Lindhard dielectric function,
the corresponding length scale is fixed by plasma screening to the Thomas-Fermi
length. The electron mean free path, however, sets a larger scale where
significant deviations from the local description are visible.Comment: 15 pages, 7 figure files (.eps), \documentclass[global]{svjour},
accepted in special issue "Optics on the Nanoscale" (Applied Physics B, eds.
V. Shalaev and F. Tr\"ager
Development of Finger Clubbing Meter
Finger clubbing, also known as drumstick finger, is the medical symptom that is indicated
by the development of the sponginess or swelling in the nail beds of nails and toes. The higher grade
of clubbing on the patients can be easily identified with the presence of drumstick finger. The
existing available measurement device to identify the early stage of clubbing required much time
which is impractical for a busy clinic practice. This paper explains the determination of the finger
clubbing by using the Digital Index (DI) measurement, which was deployed by implementing and
developing the Portable Finger Clubbing Meter hardware and the Microsoft Visual Basic (VB)
Graphical User Interface (GUI). Finger circumference values of nail-fold (NF) and distal
interphalangeal joint (DIP) of twenty participants were measured using the developed hardware.
Data analysis was then performed using the GUI for DI computation, and the presence of finger
clubbing could be determined
Towards ecologically sustainable crop production : a South African perspective
Food production comes at an ecological cost, and the lack of sustainability of South Africaâs crop
production systems is becoming increasingly worrisome. While small scale emerging and homestead
subsistence farming are significant in the agricultural sector, food production is dominated by large scale
commercial agriculture. In this paper we analyse the ecological impact of South African commercial crop
production and what can be done about it. Impact categories considered are divided into what we
consider âbetter-researchedâ problems: fresh water depletion, salinisation, soil degradation, eutrophication
and land use change; and into what we consider âemergingâ problems for agriculture: greenhouse gas
emissions, soil profile acidification, ecotoxicity and non-renewable resource consumption. While there is
a paucity of quantitative information, it is clear that after decades of cultivation many of our
agroecosystems are degraded or degrading. Sustainable crop production and food security are âwickedâ
problems â containing dynamic social, economic and biophysical complexities. Increased stakeholder
engagement to better understand these problems, the tradeoffs linked to finding solutions and to involve
those with the resources to turn knowledge into action is required. Collecting key data, turning it into
information within local contexts (involving the ecology, agronomy, sociology, psychology, economics
and other disciplines simultaneously) and communicating it effectively to allow learning and adaptive
management at various spatial and temporal scales is essential. An example is the display of river flows
on a website in real-time to help farmers manage and adapt irrigation practices better, and to connect
them with other stakeholders to improve understanding of the responsibilities of managing water at
local and catchment scales.The Water Research
Commissionhttp://www.elsevier.com/locate/agee2018-01-31hb2017Plant Production and Soil Scienc
PD1-based DNA vaccine amplifies HIV-1 GAG-specific CD8+ T cells in mice
Viral vector-based vaccines that induce protective CD8+ T cell immunity can prevent or control pathogenic SIV infections, but issues of preexisting immunity and safety have impeded their implementation in HIV-1. Here, we report the development of what we believe to be a novel antigen-targeting DNA vaccine strategy that exploits the binding of programmed death-1 (PD1) to its ligands expressed on dendritic cells (DCs) by fusing soluble PD1 with HIV-1 GAG p24 antigen. As compared with non-DC-targeting vaccines, intramuscular immunization via electroporation (EP) of the fusion DNA in mice elicited consistently high frequencies of GAG-specific, broadly reactive, polyfunctional, long-lived, and cytotoxic CD8+ T cells and robust anti-GAG antibody titers. Vaccination conferred remarkable protection against mucosal challenge with vaccinia GAG viruses. Soluble PD1-based vaccination potentiated CD8+ T cell responses by enhancing antigen binding and uptake in DCs and activation in the draining lymph node. It also increased IL-12-producing DCs and engaged antigen cross-presentation when compared with anti-DEC205 antibody-mediated DC targeting. The high frequency of durable and protective GAG-specific CD8+ T cell immunity induced by soluble PD1-based vaccination suggests that PD1-based DNA vaccines could potentially be used against HIV-1 and other pathogens.published_or_final_versio
SHR overexpression induces the formation of supernumerary cell layers with cortex cell identity in rice
The number of root cortex cell layers varies among plants, and many species have several cortical cell layers. We recently demonstrated that the two rice orthologs of the Arabidopsis SHR gene, OsSHR1 and OsSHR2, could complement the A. thaliana shr mutant. Moreover, OsSHR1 and OsSHR2 expression in A. thaliana roots induced the formation of extra root cortical cell layers. In this article, we demonstrate that the overexpression of AtSHR and OsSHR2 in rice roots leads to plants with wide and short roots that contain a high number of extra cortical cell layers. We hypothesize that SHR genes share a conserved function in the control of cortical cell layer division and the number of ground tissue cell layers in land plants
Hypothalamic loss of Snord116 recapitulates the hyperphagia of Prader-Willi syndrome.
Profound hyperphagia is a major disabling feature of Prader-Willi syndrome (PWS). Characterization of the mechanisms that underlie PWS-associated hyperphagia has been slowed by the paucity of animal models with increased food intake or obesity. Mice with a microdeletion encompassing the Snord116 cluster of noncoding RNAs encoded within the Prader-Willi minimal deletion critical region have previously been reported to show growth retardation and hyperphagia. Here, consistent with previous reports, we observed growth retardation in Snord116+/-P mice with a congenital paternal Snord116 deletion. However, these mice neither displayed increased food intake nor had reduced hypothalamic expression of the proprotein convertase 1 gene PCSK1 or its upstream regulator NHLH2, which have recently been suggested to be key mediators of PWS pathogenesis. Specifically, we disrupted Snord116 expression in the mediobasal hypothalamus in Snord116fl mice via bilateral stereotaxic injections of a Cre-expressing adeno-associated virus (AAV). While the Cre-injected mice had no change in measured energy expenditure, they became hyperphagic between 9 and 10 weeks after injection, with a subset of animals developing marked obesity. In conclusion, we show that selective disruption of Snord116 expression in the mediobasal hypothalamus models the hyperphagia of PWS
DT/T beyond linear theory
The major contribution to the anisotropy of the temperature of the Cosmic
Microwave Background (CMB) radiation is believed to come from the interaction
of linear density perturbations with the radiation previous to the decoupling
time. Assuming a standard thermal history for the gas after recombination, only
the gravitational field produced by the linear density perturbations present on
a universe can generate anisotropies at low z (these
anisotropies would manifest on large angular scales). However, secondary
anisotropies are inevitably produced during the nonlinear evolution of matter
at late times even in a universe with a standard thermal history. Two effects
associated to this nonlinear phase can give rise to new anisotropies: the
time-varying gravitational potential of nonlinear structures (Rees-Sciama RS
effect) and the inverse Compton scattering of the microwave photons with hot
electrons in clusters of galaxies (Sunyaev-Zeldovich SZ effect). These two
effects can produce distinct imprints on the CMB temperature anisotropy. We
discuss the amplitude of the anisotropies expected and the relevant angular
scales in different cosmological scenarios. Future sensitive experiments will
be able to probe the CMB anisotropies beyong the first order primary
contribution.Comment: plain tex, 16 pages, 3 figures. Proceedings of the Laredo Advance
School on Astrophysics "The universe at high-z, large-scale structure and the
cosmic microwave background". To be publised by Springer-Verla
Partonic flow and -meson production in Au+Au collisions at = 200 GeV
We present first measurements of the -meson elliptic flow
() and high statistics distributions for different
centralities from = 200 GeV Au+Au collisions at RHIC. In
minimum bias collisions the of the meson is consistent with the
trend observed for mesons. The ratio of the yields of the to those of
the as a function of transverse momentum is consistent with a model
based on the recombination of thermal quarks up to GeV/,
but disagrees at higher momenta. The nuclear modification factor () of
follows the trend observed in the mesons rather than in
baryons, supporting baryon-meson scaling. Since -mesons are
made via coalescence of seemingly thermalized quarks in central Au+Au
collisions, the observations imply hot and dense matter with partonic
collectivity has been formed at RHIC.Comment: 6 pages, 4 figures, submit to PR
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