CD28 and T cell antigen receptor signal transduction coordinately regulate interleukin 2 gene expression in response to superantigen stimulation.

Activation of an immune response requires intercellular contact between T lymphocytes and antigen-presenting cells (APC). Interaction of the T cell antigen receptor (TCR) with antigen in the context of major histocompatibility molecules mediates signal transduction, but T cell activation appears to require the induction of a second costimulatory signal transduction pathway. Recent studies suggest that interaction of CD28 with B7 on APC might deliver such a costimulatory signal. To investigate the role of CD28 signal transduction during APC-dependent T cell activation, we have used Staphylococcal enterotoxins (SEs) presented by a B7-positive APC. We used anti-B7 monoclonal antibodies and a mutant interleukin 2 (IL-2) promoter construct, unresponsive to CD28-generated signals, in transient transfection assays to examine the contribution of the CD28-B7 interaction to IL-2 gene activation. These studies indicate that the CD28-regulated signal transduction pathway is activated during SE stimulation of T cells and plays an important role in SE induction of IL-2 gene expression through its influence upon the CD28-responsive element contained within the IL-2 gene promoter. This effect is particularly profound in the activation of the IL-2 gene in peripheral blood T cells

Intermittent euxinia in the high-latitude James Ross Basin during the latest Cretaceous and earliest Paleocene

Seymour Island, in the James Ross Basin, Antarctica, contains a continuous succession of latest Cretaceous sediments deposited in a shallow marine environment at high latitude, making it an ideal place to study environmental changes prior to the K–Pg mass extinction. We measured major and trace elements and conducted petrographic analysis of two sections from the Maastrichtian–Danian López de Bertodano Formation of Seymour Island. Several lines of evidence point to intermittently anoxic to euxinic conditions during deposition, including the presence of pyrite framboids with a size distribution suggesting syngenetic formation in the water column, and enrichments in several trace elements, including molybdenum, arsenic, copper, zinc, and chromium. Molybdenum enrichments are clearly associated with enrichments in manganese and authigenic iron, suggesting “shuttling” of redox sensitive trace elements across a chemocline that fluctuated across the sediment-water interface. Comparisons with modern systems suggest relatively high frequency redox variability, possibly over approximately annual timescales, which may be related to the annual cycle of polar sunlight and associated seasonal changes in primary productivity. Glauconitic horizons are associated with more reducing conditions, including at the K–Pg boundary, though this does not appear to be a uniquely euxinic interval; similar degrees of trace element enrichment are seen in other highly glauconitic intervals. While euxinia may have contributed to low diversity in the lowermost ‘Rotularia Units’, redox conditions do not seem to have been the primary control on the transition to a mollusc dominated fauna in the latest Maastrichtian. Redox conditions show little to no response to the eruption of the Deccan Traps or Maastrichtian climatic changes. Instead, intermittent euxinia appears to have been a characteristic feature of this high-latitude environment during the Cretaceous–Paleogene transition

Guillain-Barré syndrome after tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine: a case report

<p>Abstract</p> <p>Introduction</p> <p>The association of Guillain-Barré syndrome with vaccination has been described in the literature; it is infrequent and controversial. An association with swine influenza, influenza, hepatitis and tetanus vaccination has been documented in few case reports.</p> <p>Case presentation</p> <p>A 40-year-old Caucasian man sustained a small right temporal epidural hematoma and nondisplaced right skull fractures after a fall from a roof. He was managed conservatively; a tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine was administered and a week later he was discharged home. A few days after his discharge, he experienced weakness and numbness in his legs, which progressed to involve his arms. Three weeks after his initial fall, he was readmitted with quadriparesis. A lumbar puncture revealed a cerebrospinal fluid protein of 790 mg/dL and one white blood cell. We diagnosed Guillain-Barré syndrome. Our patient was treated with intravenous immunoglobulin. Three months later his muscle strength had improved, but he continued to have tingling in his hands and feet and used a walker intermittently.</p> <p>Conclusion</p> <p>To the best of our knowledge, this is the first case of Guillain-Barré syndrome to be reported in the English literature after administration of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine.</p

The Off-Shell Electromagnetic T-matrix: momentum-dependent scattering from spherical inclusions with both dielectric and magnetic contrast

The momentum- and frequency-dependent T-matrix operator for the scattering of electromagnetic waves by a dielectric/conducting and para- or diamagnetic sphere is derived as a Mie-type series, and presented in a compact form emphasizing various symmetry properties, notably the unitarity identity. This result extends to magnetic properties one previously obtained for purely dielectric contrasts by other authors. Several situations useful to spatially-dispersive effective-medium approximations to one-body order are examined. Partial summation of the Mie series is achieved in the case of elastic scattering.Comment: 22 pages. Preprint of a paper to appear in `Waves in Complex And Random Media' ((c) Taylor and Francis, 2011

A need for the standardization of the pharmaceutical sector in Libya

Medicines are health technologies that can translate into tangible benefits for numerous acute as well as chronic health conditions. A nation's pharmaceutical sector needs to be appropriately structured and managed in order to ensure a safe, effective and quality supply of medicines to society. The process of medicines management involves the sequential management of five critical activity areas; namely; registration, selection, procurement, distribution and use. Formalized and standardized management of all five critical activity areas positively influences the availability, quality and affordability of medicines and ultimately increases the reliability and quality of the national healthcare system

Nonlinear damping in mechanical resonators based on graphene and carbon nanotubes

Carbon nanotubes and graphene allow fabricating outstanding nanomechanical resonators. They hold promise for various scientific and technological applications, including sensing of mass, force, and charge, as well as the study of quantum phenomena at the mesoscopic scale. Here, we have discovered that the dynamics of nanotube and graphene resonators is in fact highly exotic. We propose an unprecedented scenario where mechanical dissipation is entirely determined by nonlinear damping. As a striking consequence, the quality factor Q strongly depends on the amplitude of the motion. This scenario is radically different from that of other resonators, whose dissipation is dominated by a linear damping term. We believe that the difference stems from the reduced dimensionality of carbon nanotubes and graphene. Besides, we exploit the nonlinear nature of the damping to improve the figure of merit of nanotube/graphene resonators.Comment: main text with 4 figures, supplementary informatio

Anthropogenic-scale CO2 degassing from the Central Atlantic Magmatic Province as a driver of the end-Triassic mass extinction

The climatic and environmental impact of exclusively volcanic CO2 emissions is assessed during the main effusive phase of the Central Atlantic Magmatic Province (CAMP), which is synchronous with the end-Triassic mass extinction. CAMP volcanism occurred in brief and intense eruptive pulses each producing extensive basaltic lava flows. Here, CAMP volcanic CO2 injections into the surface system are modelled using a biogeochemical box model for the carbon cycle. Our modelling shows that, even if positive feedback phenomena may be invoked to explain the carbon isotope excursions preserved in end-Triassic sedimentary records, intense and pulsed volcanic activity alone may have caused repeated temperature increases and pH drops, up to 5 °C and about 0.2 log units respectively. Hence, rapid and massive volcanic CO2 emissions from CAMP, on a similar scale to current anthropogenic emissions, severely impacted on climate and environment at a global scale, leading to catastrophic biotic consequences

A close examination of double filtering with fold change and t test in microarray analysis

<p>Abstract</p> <p>Background</p> <p>Many researchers use the double filtering procedure with fold change and <it>t </it>test to identify differentially expressed genes, in the hope that the double filtering will provide extra confidence in the results. Due to its simplicity, the double filtering procedure has been popular with applied researchers despite the development of more sophisticated methods.</p> <p>Results</p> <p>This paper, for the first time to our knowledge, provides theoretical insight on the drawback of the double filtering procedure. We show that fold change assumes all genes to have a common variance while <it>t </it>statistic assumes gene-specific variances. The two statistics are based on contradicting assumptions. Under the assumption that gene variances arise from a mixture of a common variance and gene-specific variances, we develop the theoretically most powerful likelihood ratio test statistic. We further demonstrate that the posterior inference based on a Bayesian mixture model and the widely used significance analysis of microarrays (SAM) statistic are better approximations to the likelihood ratio test than the double filtering procedure.</p> <p>Conclusion</p> <p>We demonstrate through hypothesis testing theory, simulation studies and real data examples, that well constructed shrinkage testing methods, which can be united under the mixture gene variance assumption, can considerably outperform the double filtering procedure.</p

Honeybee Colony Vibrational Measurements to Highlight the Brood Cycle

Insect pollination is of great importance to crop production worldwide and honey bees are amongst its chief facilitators. Because of the decline of managed colonies, the use of sensor technology is growing in popularity and it is of interest to develop new methods which can more accurately and less invasively assess honey bee colony status. Our approach is to use accelerometers to measure vibrations in order to provide information on colony activity and development. The accelerometers provide amplitude and frequency information which is recorded every three minutes and analysed for night time only. Vibrational data were validated by comparison to visual inspection data, particularly the brood development. We show a strong correlation between vibrational amplitude data and the brood cycle in the vicinity of the sensor. We have further explored the minimum data that is required, when frequency information is also included, to accurately predict the current point in the brood cycle. Such a technique should enable beekeepers to reduce the frequency with which visual inspections are required, reducing the stress this places on the colony and saving the beekeeper time

A rocky planet transiting a nearby low-mass star

M-dwarf stars -- hydrogen-burning stars that are smaller than 60 per cent of the size of the Sun -- are the most common class of star in our Galaxy and outnumber Sun-like stars by a ratio of 12:1. Recent results have shown that M dwarfs host Earth-sized planets in great numbers: the average number of M-dwarf planets that are between 0.5 to 1.5 times the size of Earth is at least 1.4 per star. The nearest such planets known to transit their star are 39 parsecs away, too distant for detailed follow-up observations to measure the planetary masses or to study their atmospheres. Here we report observations of GJ 1132b, a planet with a size of 1.2 Earth radii that is transiting a small star 12 parsecs away. Our Doppler mass measurement of GJ 1132b yields a density consistent with an Earth-like bulk composition, similar to the compositions of the six known exoplanets with masses less than six times that of the Earth and precisely measured densities. Receiving 19 times more stellar radiation than the Earth, the planet is too hot to be habitable but is cool enough to support a substantial atmosphere, one that has probably been considerably depleted of hydrogen. Because the host star is nearby and only 21 per cent the radius of the Sun, existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere.Comment: Published in Nature on 12 November 2015, available at http://dx.doi.org/10.1038/nature15762. This is the authors' version of the manuscrip