4,423 research outputs found
Aortic clamping during elective operations for infrarenal disease: The influence of clamping time on renal function
AbstractObjective: Aortic clamping proximal to the renal arteries is sometimes necessitated during infrarenal and juxtarenal aortic surgery and may be associated with an increased risk of renal ischemia and its consequences. The aim of the study was to estimate this risk and possibly identify a āsafeā duration of renal ischemia. Methods: Medical records were retrospectively reviewed for 60 consecutive patients (from 1987 to 1994) with abdominal aortic aneurysm (n = 43) and occlusive disease (n = 17) confined to the infrarenal or juxtarenal aorta who underwent infrarenal aortic reconstruction with temporary suprarenal clamping. The data obtained included risk factors, preoperative and postoperative serum creatinine level, blood urea nitrogen (BUN) value, proteinuria before surgery, and suprarenal clamping times. Results: The mean age of the patients was 64.4 years (Ā± 11.4 years), and 74% were men. Concomitant cardiac disease was present in 41% of the patients, and 9% had diabetes. The preoperative creatinine level was 1.21 mg/dL (Ā± 0.54 mg/dL), and the BUN value was 16.6 mg/dL (Ā± 7.8 mg/dL). During surgery, blood flow to the renal arteries was interrupted for 32.0 minutes (Ā± 17 minutes). None of the surviving patients needed dialysis or had signs of acute renal failure after the operations, but transient azotemia (rise in creatinine level) occurred in 23% of the patients. Risk factors for this condition were high preoperative creatinine values and hypotension during surgery, but the main determinant was total renal ischemia time. Odds ratios for such transient renal dysfunction showed as much as a 10-fold risk when suprarenal aortic clamping was greater than 50 minutes as compared with 30 minutes or less. Conclusion: Postoperative renal function impairment is rare in this group of patients. If suprarenal clamp duration (renal ischemia time) is brief, patients with normal preoperative creatinine levels exhibit no increase or a marginal increase in BUN or creatinine levels after surgery. Accordingly, suprarenal aortic clamping less than 50 minutes in this patient group appears safe and well tolerated. (J Vasc Surg 2002;36:13-8.
Butterfly genomics : insights from the genome of Melitaea cinxia
The first lepidopteran genome (Bombyx mori) was published in 2004. Ten years later the genome of Melitaea cinxia came out as the third butterfly genome published, and the first eukaryotic genome sequenced in Finland. Owing to Ilkka Hanski, the M. cinxia system in the angstrom land Islands has become a famous model for metapopulation biology. More than 20 years of research on this system provides a strong ecological basis upon which a genetic framework could be built. Genetic knowledge is an essential addition for understanding eco-evolutionary dynamics and the genetic basis of variability in life history traits. Here we review the process of the M. cinxia genome project, its implications for lepidopteran genome evolution, and describe how the genome has been used for gene expression studies to identify genetic consequences of habitat fragmentation. Finally, we introduce some future possibilities and challenges for genomic research in M. cinxia and other Lepidoptera.Peer reviewe
The 8q24 Gene Desert: An Oasis of Non-Coding Transcriptional Activity
Understanding the functional effects of the wide-range of aberrant genetic characteristics associated with the human chromosome 8q24 region in cancer remains daunting due to the complexity of the locus. The most logical target for study remains the MYC proto-oncogene, a prominent resident of 8q24 that was first identified more than a quarter of a century ago. However, many of the amplifications, translocation breakpoints, and viral integration sites associated with 8q24 are often found throughout regions surrounding large expanses of the MYC locus that include other transcripts. In addition, chr.8q24 is host to a number of single nucleotide polymorphisms associated with cancer risk. Yet, the lack of a direct correlation between cancer risk alleles and MYC expression has also raised the possibility that MYC is not always the target of these genetic associations. The 8q24 region has been described as a āgene desertā because of the paucity of functionally annotated genes located within this region. Here we review the evidence for the role of other loci within the 8q24 region, most of which are non-coding transcripts, either in concert with MYC or independent of MYC, as possible candidate gene targets in malignancy
Conormal distributions in the Shubin calculus of pseudodifferential operators
We characterize the Schwartz kernels of pseudodifferential operators of
Shubin type by means of an FBI transform. Based on this we introduce as a
generalization a new class of tempered distributions called Shubin conormal
distributions. We study their transformation behavior, normal forms and
microlocal properties.Comment: 23 page
The Qualified Legal Compliance Committee: Using the Attorney Conduct Rules to Restructure the Board of Directors
The Securities and Exchange Commission introduced a new corporate governance structure, the qualified legal compliance committee, as part of the professional standards of conduct for attorneys mandated by the Sarbanes-Oxley Act of 2002. QLCCs are consistent with the Commission\u27s general approach to improving corporate governance through specialized committees of independent directors. This Article suggests, however, that assessing the benefits and costs of creating QLCCs may be more complex than is initially apparent. Importantly, QLCCs are unlikely to be effective in the absence of incentives for active director monitoring. This Article concludes by considering three ways of increasing these incentives
The Gabor wave front set of compactly supported distributions
We show that the Gabor wave front set of a compactly supported distribution
equals zero times the projection on the second variable of the classical wave
front set
Centaurus A at Ultra-High Energies
We review the importance of Centaurus A in high energy astrophysics as a
nearby object with many of the properties expected of a major source of very
high energy cosmic rays and gamma-rays. We examine observational techniques and
the results so far obtained in the energy range from 200 GeV to above 100 EeV
and attempt to fit those data with expectations of Centaurus A as an
astrophysical source from VHE to UHE energies.Comment: 11 pages, 4 figures, accepted for publication in PAS
Studying the nuclear mass composition of Ultra-High Energy Cosmic Rays with the Pierre Auger Observatory
The Fluorescence Detector of the Pierre Auger Observatory measures the
atmospheric depth, , where the longitudinal profile of the high energy
air showers reaches its maximum. This is sensitive to the nuclear mass
composition of the cosmic rays. Due to its hybrid design, the Pierre Auger
Observatory also provides independent experimental observables obtained from
the Surface Detector for the study of the nuclear mass composition. We present
-distributions and an update of the average and RMS values in
different energy bins and compare them to the predictions for different nuclear
masses of the primary particles and hadronic interaction models. We also
present the results of the composition-sensitive parameters derived from the
ground level component.Comment: Proceedings of the 12th International Conference on Topics in
Astroparticle and Underground Physics, TAUP 2011, Munich, German
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