523 research outputs found
The effect of transgene T-cell receptors on endogenous delta gene transcripts
Thesis (B.S.) in Biochemistry -- University of Illinois at Urbana-Champaign, 1988.Includes bibliographical references (leaves 16-17)Microfiche of typescript. [Urbana, Ill.]: Photographic Services, University of Illinois, U of I Library, [1988]. 1 microfiche (32 frames): negative.s 1988 ilu n
The epidemiology of chronic kidney disease in sub-Saharan Africa: a systematic review and meta-analysis
Background Amid rapid urbanisation, the HIV epidemic, and increasing rates of non-communicable diseases, people
in sub-Saharan Africa are especially vulnerable to kidney disease. Little is known about the epidemiology of chronic
kidney disease (CKD) in sub-Saharan Africa, so we did a systematic review and meta-analysis examining the
epidemiology of the disease.
Methods We searched Medline, Embase, and WHO Global Health Library databases for all articles published through
March 29, 2012, and searched the reference lists of retrieved articles. We independently reviewed each study for
quality. We used the inverse-variance random-eff ects method for meta-analyses of the medium-quality and highquality
data and explored heterogeneity by comparing CKD burdens across countries, settings (urban or rural),
comorbid disorders (hypertension, diabetes, HIV), CKD defi nitions, and time.
Findings Overall, we included 90 studies from 96 sites in the review. Study quality was low, with only 18 (20%)
medium-quality studies and three (3%) high-quality studies. We noted moderate heterogeneity between the mediumquality
and high-quality studies (n=21; I²=47·11%, p<0·0009). Measurement of urine protein was the most common
method of determining the presence of kidney disease (62 [69%] studies), but the Cockcroft-Gault formula (22 [24%]
studies) and Modifi cation of Diet in Renal Disease formula (17 [19%] studies) were also used. Most of the studies
were done in urban settings (83 [93%] studies) and after the year 2000 (57 [63%] studies), and we detected no
signifi cant diff erence in the prevalence of CKD between urban (12·4%, 95% CI 11–14) and rural (16·5%, 13·8–19·6)
settings (p=0·474). The overall prevalence of CKD from the 21 medium-quality and high-quality studies was 13·9%
(95% CI 12·2–15·7).
Interpretation In sub-Saharan Africa, CKD is a substantial health burden with risk factors that include communicable
and non-communicable diseases. However, poor data quality limits inferences and draws attention to the need for
more information and validated measures of kidney function especially in the context of the growing burden of noncommunicable diseases
Anomalous layering at the liquid Sn surface
X-ray reflectivity measurements on the free surface of liquid Sn are
presented. They exhibit the high-angle peak, indicative of surface-induced
layering, also found for other pure liquid metals (Hg, Ga and In). However, a
low-angle peak, not hitherto observed for any pure liquid metal, is also found,
indicating the presence of a high-density surface layer. Fluorescence and
resonant reflectivity measurements rule out the assignment of this layer to
surface-segregation of impurities. The reflectivity is modelled well by a 10%
contraction of the spacing between the first and second atomic surface layers,
relative to that of subsequent layers. Possible reasons for this are discussed.Comment: 8 pages, 9 figures; to be submitted to Phys. Rev. B; updated
references, expanded discussio
BICEP2 II: Experiment and Three-Year Data Set
We report on the design and performance of the BICEP2 instrument and on its
three-year data set. BICEP2 was designed to measure the polarization of the
cosmic microwave background (CMB) on angular scales of 1 to 5 degrees
(=40-200), near the expected peak of the B-mode polarization signature of
primordial gravitational waves from cosmic inflation. Measuring B-modes
requires dramatic improvements in sensitivity combined with exquisite control
of systematics. The BICEP2 telescope observed from the South Pole with a 26~cm
aperture and cold, on-axis, refractive optics. BICEP2 also adopted a new
detector design in which beam-defining slot antenna arrays couple to
transition-edge sensor (TES) bolometers, all fabricated on a common substrate.
The antenna-coupled TES detectors supported scalable fabrication and
multiplexed readout that allowed BICEP2 to achieve a high detector count of 500
bolometers at 150 GHz, giving unprecedented sensitivity to B-modes at degree
angular scales. After optimization of detector and readout parameters, BICEP2
achieved an instrument noise-equivalent temperature of 15.8 K sqrt(s). The
full data set reached Stokes Q and U map depths of 87.2 nK in square-degree
pixels (5.2 K arcmin) over an effective area of 384 square degrees within
a 1000 square degree field. These are the deepest CMB polarization maps at
degree angular scales to date. The power spectrum analysis presented in a
companion paper has resulted in a significant detection of B-mode polarization
at degree scales.Comment: 30 pages, 24 figure
BICEP2 / Keck Array VIII: Measurement of gravitational lensing from large-scale B-mode polarization
We present measurements of polarization lensing using the 150 GHz maps which
include all data taken by the BICEP2 & Keck Array CMB polarization experiments
up to and including the 2014 observing season (BK14). Despite their modest
angular resolution (), the excellent sensitivity (K-arcmin) of these maps makes it possible to directly reconstruct the
lensing potential using only information at larger angular scales (). From the auto-spectrum of the reconstructed potential we measure an
amplitude of the spectrum to be (Planck
CDM prediction corresponds to ), and reject
the no-lensing hypothesis at 5.8, which is the highest significance
achieved to date using an EB lensing estimator. Taking the cross-spectrum of
the reconstructed potential with the Planck 2015 lensing map yields
. These direct measurements of
are consistent with the CDM cosmology, and with
that derived from the previously reported BK14 B-mode auto-spectrum (). We perform a series of null tests and consistency
checks to show that these results are robust against systematics and are
insensitive to analysis choices. These results unambiguously demonstrate that
the B-modes previously reported by BICEP / Keck at intermediate angular scales
() are dominated by gravitational lensing. The
good agreement between the lensing amplitudes obtained from the lensing
reconstruction and B-mode spectrum starts to place constraints on any
alternative cosmological sources of B-modes at these angular scales.Comment: 12 pages, 8 figure
X-ray study of the electric double layer at the n-hexane/nanocolloidal silica interface
The spatial structure of the transition region between an insulator and an
electrolyte solution was studied with x-ray scattering.The electron density
profile across the n-hexane/silica sol interface (solutions with 5-nm, 7-nm,
and 12-nm colloidal particles) agrees with the theory of the electrical double
layer and shows separation of positive and negative charges. The interface
consists of three layers, i.e., a compact layer of Na+, a loose monolayer of
nanocolloidal particles as part of a thick diffuse layer, and a low-density
layer sandwiched between them. Its structure is described by a model in which
the potential gradient at the interface reflects the difference in the
potentials of "image forces" between the cationic Na+ and anionic nanoparticles
and the specific adsorption of surface charge. The density of water in the
large electric field (1-10 GV/m) of the transition region and the layering of
silica in the diffuse layer is discussed.Comment: 9 pages, 9 figure
- …