4,320 research outputs found
Genetic and serological heterogeneity of the supertypic HLA-B locus specificities Bw4 and Bw6
Gene cloning and sequencing of the HLA-B
locus split antigens B38 (B16.1) and B39 (B16.2) allowed
localization of their subtypic as well as their public
specificities HLA-Bw4 or -Bw6 to the c~-helical region of
the c~ 1 domain flanked by the amino acid positions 74-83.
Comparison of their amino acid sequences with those of
other HLA-B-locus alleles established HLA-Bw6 to be
distinguished by Ser at residue 77 and Asn at residue 80.
In contrast, HLA-Bw4 is characterized by at least seven
different patterns of amino acid exchanges at positions 77
and 80-83. Reactivity patterns of Bw4- or Bw6-specific
monoclonal antibodies reveal two alloantigenic epitopes
contributing to the HLA-Bw4 or -Bw6 specificity residing
next to the region of highest diversity of the cr domain
PLENARY PANEL: A 360-DEGREE VIEW OF SCIENCE AND AGRICULTURAL POLICY; EDITED TRANSCRIPT
Agricultural and Food Policy,
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Analysis of exceedances in the daily PM10 mass concentration (50 μg m−3) at a roadside station in Leipzig, Germany
Five years of PM10 and PM2.5 ambient air measurements at a roadside, an urban, and a regional background site in Leipzig (Germany) were analyzed for violations of the legal PM10 limit value (EC, 1999). The annual mean PM10 concentrations at the three sites were well below the legal threshold of 40 μg m−3 (32.6, 22.0 and 21.7 μg m−3, respectively). At roadside, the daily maximum value of 50 μg m−3 was exceeded on 232 days (13% of all days) in 2005–2009, which led to a violation of the EC directive in three out of five years. We analysed the meteorological factors and local source contributions that eventually led to the exceedances of the daily limit value. As noted in other urban environments before, most exceedance days were observed in the cold season. Exceedance days were most probable under synoptic situations characterised by stagnant winds, low temperatures and strong temperature inversions in winter time. However, these extreme situations accounted for only less than half of the exeedance days. We also noticed a significant number of exceedance days that occurred in the cold season under south-westerly winds, and in the warm season in the presence of easterly winds. Our analysis suggests that local as well as regional sources of PM are equally responsible for exceedances days at the roadside site. The conclusion is that a combined effort of local, national and international reduction measures appears most likely to avoid systematic exceedances of the daily limit value in the future
Functional Implications in Apoptosis by Interferon Inducible Gene Product 1-8D, the Binding Protein to Adenovirus Preterminal Protein
Adenovirus (Ad) precursor to the terminal protein (pTP) plays an essential roles in the viral DNA
replication. Ad pTP serves as a primer for the synthesis of a new DNA strand during the initiation
step of replication. In addition, Ad pTP forms organized spherical replication foci on the nuclear
matrix (NM) and anchors the viral genome to the NM. Here we identified the interferon inducible
gene product 1-8D (Inid) as a pTP binding protein by using a two-hybrid screen of a HeLa cDNA
library. Of the clones obtained in this assay, nine were identical to the Inid, a 13-kDa polypeptide
that shares homology with genes 1-8U and Leu-13/9-27, most of which have little known functions.
The entire open reading frame (ORF) of Inid was cloned into the tetracycline inducible expression
vector in order to determine the biological functions related with adenoviral infection. When Inid
was introduced to the cells along with adenoviruses, fifty to sixty percent of Ad-infected cells
expressing Inid had rounded morphology, which was suggestive of apoptosis. Results from the
terminal deoxynucleotidyl transferase (TdT) and DNA fragmentation assays confirmed that Inid
induces apoptosis in Ad-infected or in uninfected cells. The Inid binding to pTP may target the cell
for apoptotic destruction as a host defense mechanism against the viral infection
Diffractive triangulation of radiative point sources
We describe a general method to determine the location of a point source of waves relative to a twodimensional
single-crystalline active pixel detector. Based on the inherent structural sensitivity of
crystalline sensor materials, characteristic detector diffraction patterns can be used to triangulate the
location of a wave emitter. The principle described here can be applied to various types of waves,
provided that the detector elements are suitably structured. As a prototypical practical application of
the general detection principle, a digital hybrid pixel detector is used to localize a source of electrons
for Kikuchi diffraction pattern measurements in the scanning electron microscope. This approach
provides a promising alternative method to calibrate Kikuchi patterns for accurate measurements of
microstructural crystal orientations, strains, and phase distributions
Terrestrial Effects Of Nearby Supernovae In The Early Pleistocene
Recent results have strongly confirmed that multiple supernovae happened at
distances ~100 pc consisting of two main events: one at 1.7 to 3.2 million
years ago, and the other at 6.5 to 8.7 million years ago. These events are said
to be responsible for excavating the Local Bubble in the interstellar medium
and depositing 60Fe on Earth and the Moon. Other events are indicated by
effects in the local cosmic ray (CR) spectrum. Given this updated and refined
picture, we ask whether such supernovae are expected to have had substantial
effects on the terrestrial atmosphere and biota. In a first cut at the most
probable cases, combining photon and cosmic ray effects, we find that a
supernova at 100 pc can have only a small effect on terrestrial organisms from
visible light and that chemical changes such as ozone depletion are weak.
However, tropospheric ionization right down to the ground due to the
penetration of TeV cosmic rays will increase by nearly an order of
magnitude for thousands of years, and irradiation by muons on the ground and in
the upper ocean will increase 20-fold, which will approximately triple the
overall radiation load on terrestrial organisms. Such irradiation has been
linked to possible changes in climate and increased cancer and mutation rates.
This may be related to a minor mass extinction around the Pliocene-Pleistocene
boundary, and further research on the effects is needed.Comment: Revised version accepted at ApJ
A Difference Version of Nori's Theorem
We consider (Frobenius) difference equations over (F_q(s,t), phi) where phi
fixes t and acts on F_q(s) as the Frobenius endomorphism. We prove that every
semisimple, simply-connected linear algebraic group G defined over F_q can be
realized as a difference Galois group over F_{q^i}(s,t) for some i in N. The
proof uses upper and lower bounds on the Galois group scheme of a Frobenius
difference equation that are developed in this paper. The result can be seen as
a difference analogue of Nori's Theorem which states that G(F_q) occurs as
(finite) Galois group over F_q(s).Comment: 29 page
Atmospheric number size distributions of soot particles and estimation of emission factors
International audienceNumber fractions of externally mixed particles of four different sizes (30, 50, 80, and 150 nm in diameter) were measured using a Volatility Tandem DMA. The system was operated in a street canyon (Eisenbahnstrasse, EI) and at an urban background site (Institute for Tropospheric Research, IfT), both in the city of Leipzig, Germany as well as at a rural site (Melpitz (ME), a village near Leipzig). Intensive campaigns of 3?5 weeks each took place in summer 2003 as well as in winter 2003/2004. The data set thus obtained provides mean number fractions of externally mixed soot particles of atmospheric aerosols in differently polluted areas and different seasons (e.g. at 80 nm on working days, 60% (EI), 22% (IfT), and 6% (ME) in summer and 26% (IfT), and 13% (ME) in winter). Furthermore, a new method is used to calculate the size distribution of these externally mixed soot particles from parallel number size distribution measurements. A decrease of the externally mixed soot fraction with decreasing urbanity and a diurnal variation linked to the daily traffic changes demonstrate, that the traffic emissions have a significant impact on the soot fraction in urban areas. This influence becomes less in rural areas, due to atmospheric mixing and transformation processes. For estimating the source strength of soot particles emitted by vehicles (veh), soot particle emission factors were calculated using the Operational Street Pollution Model (OSPM). The emission factor for an average vehicle was found to be (1.5±0.4)·1014 #/(km·veh). The separation of the emission factor into passenger cars ((5.8±2)·1013 #/(km·veh)) and trucks ((2.5±0.9)·1015 #/(km·veh)) yielded in a 40-times higher emission factor for trucks compared to passenger cars
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