2,069 research outputs found
Representational affordances in design, with examples from analogy making and optimization
An international comparative study of blood pressure in populations of European vs. African descent
Background: The consistent finding of higher prevalence of hypertension in US blacks compared
to whites has led to speculation that African-origin populations are particularly susceptible to this
condition. Large surveys now provide new information on this issue.
Methods: Using a standardized analysis strategy we examined prevalence estimates for 8 white
and 3 black populations (N = 85,000 participants).
Results: The range in hypertension prevalence was from 27 to 55% for whites and 14 to 44% for
blacks.
Conclusions: These data demonstrate that not only is there a wide variation in hypertension
prevalence among both racial groups, the rates among blacks are not unusually high when viewed
internationally. These data suggest that the impact of environmental factors among both
populations may have been under-appreciated
Effect of osteoprotegerin and pamidronate treatment in transgenic mice overexpressing human TNF
Upregulation of the cell-cycle regulator RGC-32 in Epstein-Barr virus-immortalized cells
Epstein-Barr virus (EBV) is implicated in the pathogenesis of multiple human tumours of lymphoid and epithelial origin. The virus infects and immortalizes B cells establishing a persistent latent infection characterized by varying patterns of EBV latent gene expression (latency 0, I, II and III). The CDK1 activator, Response Gene to Complement-32 (RGC-32, C13ORF15), is overexpressed in colon, breast and ovarian cancer tissues and we have detected selective high-level RGC-32 protein expression in EBV-immortalized latency III cells. Significantly, we show that overexpression of RGC-32 in B cells is sufficient to disrupt G2 cell-cycle arrest consistent with activation of CDK1, implicating RGC-32 in the EBV transformation process. Surprisingly, RGC-32 mRNA is expressed at high levels in latency I Burkitt's lymphoma (BL) cells and in some EBV-negative BL cell-lines, although RGC-32 protein expression is not detectable. We show that RGC-32 mRNA expression is elevated in latency I cells due to transcriptional activation by high levels of the differentially expressed RUNX1c transcription factor. We found that proteosomal degradation or blocked cytoplasmic export of the RGC-32 message were not responsible for the lack of RGC-32 protein expression in latency I cells. Significantly, analysis of the ribosomal association of the RGC-32 mRNA in latency I and latency III cells revealed that RGC-32 transcripts were associated with multiple ribosomes in both cell-types implicating post-initiation translational repression mechanisms in the block to RGC-32 protein production in latency I cells. In summary, our results are the first to demonstrate RGC-32 protein upregulation in cells transformed by a human tumour virus and to identify post-initiation translational mechanisms as an expression control point for this key cell-cycle regulator
Chronic nonpuerperal uterine inversion and necrosis: a case report
<p>Abstract</p> <p><b>Introduction</b></p> <p>Inversion of the non-pregnant uterus is rare.</p> <p><b>Case presentation</b></p> <p>A 56-year-old African American woman presented to our emergency center with complaints of a mass protruding from her vagina. She subsequently underwent vaginal myomectomy, abdominal hysterectomy and bilateral salpingo-oophorectomy. Pathologic examination revealed a necrotic fibroid and endometrium. At the time of laparotomy an inverted uterus was diagnosed when a 3 cm dimple containing bilateral round ligaments, infundibulopelvic ligaments and bladder was observed.</p> <p>Conclusion</p> <p>Chronic nonpuerperal inversion of the uterus is rare. Infection should be suspected and appropriate broad spectrum antibiotics begun while planning surgery. An attempt at vaginal restoration and removal is difficult. Abdominal hysterectomy may be necessary taking care to locate the distal urinary collecting system.</p
Electronic Origin of High Temperature Superconductivity in Single-Layer FeSe Superconductor
The latest discovery of high temperature superconductivity signature in
single-layer FeSe is significant because it is possible to break the
superconducting critical temperature ceiling (maximum Tc~55 K) that has been
stagnant since the discovery of Fe-based superconductivity in 2008. It also
blows the superconductivity community by surprise because such a high Tc is
unexpected in FeSe system with the bulk FeSe exhibiting a Tc at only 8 K at
ambient pressure which can be enhanced to 38 K under high pressure. The Tc is
still unusually high even considering the newly-discovered intercalated FeSe
system A_xFe_{2-y}Se_2 (A=K, Cs, Rb and Tl) with a Tc at 32 K at ambient
pressure and possible Tc near 48 K under high pressure. Particularly
interesting is that such a high temperature superconductivity occurs in a
single-layer FeSe system that is considered as a key building block of the
Fe-based superconductors. Understanding the origin of high temperature
superconductivity in such a strictly two-dimensional FeSe system is crucial to
understanding the superconductivity mechanism in Fe-based superconductors in
particular, and providing key insights on how to achieve high temperature
superconductivity in general. Here we report distinct electronic structure
associated with the single-layer FeSe superconductor. Its Fermi surface
topology is different from other Fe-based superconductors; it consists only of
electron pockets near the zone corner without indication of any Fermi surface
around the zone center. Our observation of large and nearly isotropic
superconducting gap in this strictly two-dimensional system rules out existence
of node in the superconducting gap. These results have provided an unambiguous
case that such a unique electronic structure is favorable for realizing high
temperature superconductivity
Structural and magnetic phase diagram of CeFeAsO1-xFx and its relationship to high-temperature superconductivity
We use neutron scattering to study the structural and magnetic phase
transitions in the iron pnictides CeFeAsO1-xFx as the system is tuned from a
semimetal to a high-transition-temperature (high-Tc) superconductor through
Fluorine (F) doping x. In the undoped state, CeFeAsO develops a structural
lattice distortion followed by a stripe like commensurate antiferromagnetic
order with decreasing temperature. With increasing Fluorine doping, the
structural phase transition decreases gradually while the antiferromagnetic
order is suppressed before the appearance of superconductivity, resulting an
electronic phase diagram remarkably similar to that of the high-Tc copper
oxides. Comparison of the structural evolution of CeFeAsO1-xFx with other
Fe-based superconductors reveals that the effective electronic band width
decreases systematically for materials with higher Tc. The results suggest that
electron correlation effects are important for the mechanism of high-Tc
superconductivity in these Fe pnictides.Comment: 19 pages, 5 figure
Towards Quantum Repeaters with Solid-State Qubits: Spin-Photon Entanglement Generation using Self-Assembled Quantum Dots
In this chapter we review the use of spins in optically-active InAs quantum
dots as the key physical building block for constructing a quantum repeater,
with a particular focus on recent results demonstrating entanglement between a
quantum memory (electron spin qubit) and a flying qubit (polarization- or
frequency-encoded photonic qubit). This is a first step towards demonstrating
entanglement between distant quantum memories (realized with quantum dots),
which in turn is a milestone in the roadmap for building a functional quantum
repeater. We also place this experimental work in context by providing an
overview of quantum repeaters, their potential uses, and the challenges in
implementing them.Comment: 51 pages. Expanded version of a chapter to appear in "Engineering the
Atom-Photon Interaction" (Springer-Verlag, 2015; eds. A. Predojevic and M. W.
Mitchell
Ventricular beat detection in single channel electrocardiograms
BACKGROUND: Detection of QRS complexes and other types of ventricular beats is a basic component of ECG analysis. Many algorithms have been proposed and used because of the waves' shape diversity. Detection in a single channel ECG is important for several applications, such as in defibrillators and specialized monitors. METHODS: The developed heuristic algorithm for ventricular beat detection includes two main criteria. The first of them is based on steep edges and sharp peaks evaluation and classifies normal QRS complexes in real time. The second criterion identifies ectopic beats by occurrence of biphasic wave. It is modified to work with a delay of one RR interval in case of long RR intervals. Other algorithm branches classify already detected QRS complexes as ectopic beats if a set of wave parameters is encountered or the ratio of latest two RR intervals RR(i-1)/RR(i )is less than 1:2.5. RESULTS: The algorithm was tested with the AHA and MIT-BIH databases. A sensitivity of 99.04% and a specificity of 99.62% were obtained in detection of 542014 beats. CONCLUSION: The algorithm copes successfully with different complicated cases of single channel ventricular beat detection. It is aimed to simulate to some extent the experience of the cardiologist, rather than to rely on mathematical approaches adopted from the theory of signal analysis. The algorithm is open to improvement, especially in the part concerning the discrimination between normal QRS complexes and ectopic beats
Refinement of the GINGF3 locus for hereditary gingival fibromatosis
Hereditary gingival fibromatosis (HGF) is a rare, clinically variable disorder characterized by slowly progressive fibrous overgrowth of the gingiva. Four gene loci have been mapped for autosomal dominant non-syndromic HGF (adHGF). The molecular basis of adHGF remains largely unknown, with only a single SOS1 gene mutation identified so far at the gingival fibromatosis 1 (GINGF1) locus in one family. We identified an adHGF family with ten affected individuals in whom onset of gingival fibromatosis concurred with the eruption of the primary teeth. In order to identify the molecular basis in this family, we tested for linkage of the disease to known adHGF loci. A maximal multipoint logarithm of the odds score of 3.91 was obtained with marker D2S390 (θ = 0) at the GINGF3 locus on chromosome 2p23.3–p22.3, and linkage to other known loci was excluded. Sequencing two candidate genes, ALK and C2orf18, and a single nucleotide polymorphisms array analysis did not reveal a mutation or copy number variation in a patient from the family. We refined the GINGF3 locus to a 6.56-cM, 8.27-Mb region containing 112 known and hypothetical genes, and our data and a search of the literature suggest that GINGF3 is a major adHGF locus
- …