20,628 research outputs found
Estrogenic activity of phenolic additives determined by an in vitro yeast bioassay
Copyright @ 2001 Environmental Health PerspectivesWe used a recombinant yeast estrogen assay to assess the activity of 73 phenolic additives that are used as sunscreens, preservatives, disinfectants, antioxidants, flavorings, or for perfumery. Thirty-two of these compounds displayed activity: 22 with potencies relative to 17 beta -estradiol, ranging from 1/3,000 to -estradiol. Forty-one compounds were inactive. The major criteria for activity appear to be the presence of an unhindered phenolic OH group in a para position and a molecular weight of 140-250 Da.This work was supported in part under contract with the U.K. Department of Trade and Industry as part of the Government Chemist Programme
Prediction Possibility in the Fractal Overlap Model of Earthquakes
The two-fractal overlap model of earthquake shows that the contact area
distribution of two fractal surfaces follows power law decay in many cases and
this agrees with the Guttenberg-Richter power law. Here, we attempt to predict
the large events (earthquakes) in this model through the overlap time-series
analysis. Taking only the Cantor sets, the overlap sizes (contact areas) are
noted when one Cantor set moves over the other with uniform velocity. This
gives a time series containing different overlap sizes. Our numerical study
here shows that the cumulative overlap size grows almost linearly with time and
when the overlapsizes are added up to a pre-assigned large event (earthquake)
and then reset to `zero' level, the corresponding cumulative overlap sizes
grows upto some discrete (quantised) levels. This observation should help to
predict the possibility of `large events' in this (overlap) time series.Comment: 6 pages, 6 figures. To be published as proc. NATO conf. CMDS-10,
Soresh, Israel, July 2003. Eds. D. J. Bergman & E. Inan, KLUWER PUB
Sanitation and hygiene status of butcheries in Kampala district, Uganda
There is a growing trend in the consumption of animal products such as meat in the developing world especially due to a growing population, urbanization and rising incomes. This poses a risk of food borne illnesses from meat consumption due to poor sanitation and hygiene. The purpose of this study was to assess the sanitation and hygiene status of butcheries in Kampala district, Uganda. The study was cross-sectional in design and involved quantitative data collection methods. The study units were butcheries from which one respondent was randomly selected to answer the questionnaire. An observational checklist was used to assess the status of sanitation and hygiene of the butcheries. Data were entered and analysed in Epi Info 3.5.1 statistical software. A total of 73 butcheries were visited, 51 (69.9%) of which were permanent structures, 7 (9.6%) semi-permanent and 15 (20.5%) temporary. Observations revealed that 24 (32.9%) butcheries had cracked walls and 66 (90.4%) had damaged floors. The main water source used by the butcheries was tap 67 (91.8%) with the rest collecting water from nearby protected springs. Hand washing facilities were present in 56 (76.7%) of the butcheries of which only 5 (6.8%) had soap for hand washing. Only 19 (26.0%) of the butcheries had receptacles for waste storage. Cleaning practices varied among butchers with 55 (75.3%) cleaning their butcheries daily. Most of the equipment (pangas and knives) found in the butcheries 66 (90.4%) were clean. Regarding personal hygiene, 57 (78.1%) of the respondents wore clean clothes, 65 (89.0%) had short finger nails and only 23 (31.5%) had personal protective wear. From the study, it was observed that the sanitation and hygiene status of butcheries in Kampala district was poor. There is, thus, need for the local authority to put in place stringent measures to ensure proper hygiene and sanitation which will reduce on the risks of meat contamination.Key words: butcheries, hygiene, knowledge, sanitation, Ugand
Lymphotoxin is an autocrine growth factor for Epstein-Barr virus-infected B cell lines.
Because human lymphotoxin (LT) was originally isolated from a lymphoblastoid cell line, we investigated the role of this molecule in three newly established Epstein-Barr virus (EBV)-infected human B cell lines. These lines were derived from acute lymphoblastic leukemia (Z-6), myelodysplastic syndrome (Z-43), and acute myelogenous leukemia (Z-55) patients who had a prior EBV infection. Each lymphoblastoid cell line had a karyotype that was different from that of the original parent leukemic cells, and all expressed B cell, but not T cell or myeloid surface markers. In all three lines, rearranged immunoglobulin heavy chain joining region (JH) bands were found, and the presence of EBV DNA was confirmed by Southern blotting. Z-6, Z-43, and Z-55 cell lines constitutively produced 192, 48, and 78 U/ml LT, respectively, as assessed by a cytotoxicity assay and antibody neutralization. Levels of tumor necrosis factor (TNF) were undetectable. Scatchard analysis revealed that all the cell lines expressed high-affinity TNF/LT receptors with receptor densities of 4197, 1258, and 1209 sites/cell on Z-6, Z-43, and Z-55, respectively. Furthermore, labeled TNF binding could be reversed by both unlabeled TNF, as well as by LT. Studies with p60 and p80 receptor-specific antibodies revealed that the three lines expressed primarily the p80 form of the TNF receptor. When studied in a clonogenic assay, exogenous LT stimulated proliferation of all three cell lines in a dose-dependent fashion at concentrations ranging from 25 to 500 U/ml. Similar results were obtained with [3H]TdR incorporation. Monoclonal anti-LT neutralizing antibodies at concentrations of 25-500 U/ml inhibited cellular multiplication in a dose-dependent manner. It is interesting that in spite of a common receptor, TNF (1,000 U/ml) had no direct effect on Z-55 cell growth, whereas it partially reversed the stimulatory effect of exogenous LT. In addition, TNF inhibited Z-6 and Z-43 cell proliferation, and its suppressive effect was reversed by exogenous LT. Both p80 and p60 forms of soluble TNF receptors suppressed the lymphoblastoid cell line proliferation and their inhibitory effect was partially reversed by LT. Our data suggest that (a) LT is an autocrine growth factor for EBV-transformed lymphoblastoid B cell lines; and (b) anti-LT antibodies, soluble TNF/LT receptors, and TNF itself can suppress the growth of lymphoblastoid cells, probably by modulating or competing with LT.(ABSTRACT TRUNCATED AT 400 WORDS
HardIDX: Practical and Secure Index with SGX
Software-based approaches for search over encrypted data are still either
challenged by lack of proper, low-leakage encryption or slow performance.
Existing hardware-based approaches do not scale well due to hardware
limitations and software designs that are not specifically tailored to the
hardware architecture, and are rarely well analyzed for their security (e.g.,
the impact of side channels). Additionally, existing hardware-based solutions
often have a large code footprint in the trusted environment susceptible to
software compromises. In this paper we present HardIDX: a hardware-based
approach, leveraging Intel's SGX, for search over encrypted data. It implements
only the security critical core, i.e., the search functionality, in the trusted
environment and resorts to untrusted software for the remainder. HardIDX is
deployable as a highly performant encrypted database index: it is logarithmic
in the size of the index and searches are performed within a few milliseconds
rather than seconds. We formally model and prove the security of our scheme
showing that its leakage is equivalent to the best known searchable encryption
schemes. Our implementation has a very small code and memory footprint yet
still scales to virtually unlimited search index sizes, i.e., size is limited
only by the general - non-secure - hardware resources
Anatomically Constrained Video-CT Registration via the V-IMLOP Algorithm
Functional endoscopic sinus surgery (FESS) is a surgical procedure used to
treat acute cases of sinusitis and other sinus diseases. FESS is fast becoming
the preferred choice of treatment due to its minimally invasive nature.
However, due to the limited field of view of the endoscope, surgeons rely on
navigation systems to guide them within the nasal cavity. State of the art
navigation systems report registration accuracy of over 1mm, which is large
compared to the size of the nasal airways. We present an anatomically
constrained video-CT registration algorithm that incorporates multiple video
features. Our algorithm is robust in the presence of outliers. We also test our
algorithm on simulated and in-vivo data, and test its accuracy against
degrading initializations.Comment: 8 pages, 4 figures, MICCA
Emergent quantum Euler equation and Bose-Einstein condensates
In this paper, proceeding from the recently developed way of deriving the
quantum-mechanical equations from the classical ones, the complete system of
hydrodynamical equations, including the quantum Euler equation, is derived for
a perfect fluid and an imperfect fluid with pairwise interaction between the
particles. For the Bose-Einstein condensate of the latter one the Bogolyubov
spectrum of elementary excitations is easily reproduced in the acoustic
approximation.Comment: 10 page
Patterns in high-frequency FX data: Discovery of 12 empirical scaling laws
We have discovered 12 independent new empirical scaling laws in foreign
exchange data-series that hold for close to three orders of magnitude and
across 13 currency exchange rates. Our statistical analysis crucially depends
on an event-based approach that measures the relationship between different
types of events. The scaling laws give an accurate estimation of the length of
the price-curve coastline, which turns out to be surprisingly long. The new
laws substantially extend the catalogue of stylised facts and sharply constrain
the space of possible theoretical explanations of the market mechanisms.Comment: 26 pages, 3 figures, 23 tables,2nd version (text made more concise
and readable, algorithm pseudocode, results unchanged), 5-year datasets
(USD-JPY, EUR-USD) provided at http://www.olsen.ch/more/datasets
Bounded Verification with On-the-Fly Discrepancy Computation
Simulation-based verification algorithms can provide formal safety guarantees
for nonlinear and hybrid systems. The previous algorithms rely on user provided
model annotations called discrepancy function, which are crucial for computing
reachtubes from simulations. In this paper, we eliminate this requirement by
presenting an algorithm for computing piece-wise exponential discrepancy
functions. The algorithm relies on computing local convergence or divergence
rates of trajectories along a simulation using a coarse over-approximation of
the reach set and bounding the maximal eigenvalue of the Jacobian over this
over-approximation. The resulting discrepancy function preserves the soundness
and the relative completeness of the verification algorithm. We also provide a
coordinate transformation method to improve the local estimates for the
convergence or divergence rates in practical examples. We extend the method to
get the input-to-state discrepancy of nonlinear dynamical systems which can be
used for compositional analysis. Our experiments show that the approach is
effective in terms of running time for several benchmark problems, scales
reasonably to larger dimensional systems, and compares favorably with respect
to available tools for nonlinear models.Comment: 24 page
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