69,707 research outputs found
Synthesis of Neocaesalpin A, AA, and Nominal Neocaesalpin K
No full textThe first total synthesis of heavily oxidized cassane-type diterpenoid neocaesalpin A (1) is dis-closed. At the heart of the synthesis lies an intermolecular Diels–Alder reaction that rapidly assem-bles the target framework from commercial materials. A carefully orchestrated sequence of oxida-tions secured the desired oxygenation pattern. Late-stage release of the characteristic butenolide occurred through a novel mercury(II)-mediated furan oxidation. Successful extension of the route allowed preparation of neocaesalpin AA (2) as well as nominal neocaesalpin K (3) and suggested structural revision of neocaesalpin K, leading to the hypothesis that the two are likely the same natural product with correct assignment as 2
Natural history and outcome in systemic AA amyloidosis
No full textBACKGROUND:Deposition of amyloid fibrils derived from circulating acute-phase reactant serum amyloid A protein (SAA) causes systemic AA amyloidosis, a serious complication of many chronic inflammatory disorders. Little is known about the natural history of AA amyloidosis or its response to treatment.METHODS:We evaluated clinical features, organ function, and survival among 374 patients with AA amyloidosis who were followed for a median of 86 months. The SAA concentration was measured serially, and the amyloid burden was estimated with the use of whole-body serum amyloid P component scintigraphy. Therapy for inflammatory diseases was administered to suppress the production of SAA.RESULTS:Median survival after diagnosis was 133 months; renal dysfunction was the predominant disease manifestation. Mortality, amyloid burden, and renal prognosis all significantly correlated with the SAA concentration during follow-up. The risk of death was 17.7 times as high among patients with SAA concentrations in the highest eighth, or octile, (greater/equal 155 mg per liter) as among those with concentrations in the lowest octile (< 4 mg per liter); and the risk of death was four times as high in the next-to-lowest octile (4 to 9 mg per liter). The median SAA concentration during follow-up was 6 mg per liter in patients in whom renal function improved and 28 mg per liter in those in whom it deteriorated (P < 0.001). Amyloid deposits regressed in 60% of patients who had a median SAA concentration of less than 10 mg per liter, and survival among these patients was superior to survival among those in whom amyloid deposits did not regress (P=0.04).CONCLUSIONS:The effects of renal dysfunction dominate the course of AA amyloidosis, which is associated with a relatively favorable outcome in patients with SAA concentrations that remain in the low-normal range (< 4 mg per liter)
Renal AA-amyloidosis in intravenous drug users - a role for HIV-infection?
No full textBackground: Chronic renal disease is a serious complication of long-term intravenous drug use (IVDU). Recent reports have postulated a changing pattern of underlying nephropathy over the last decades.
Methods: Retrospective investigation including all patients with prior or present IVDU that underwent renal biopsy because of chronic kidney disease between 01.04.2002 and 31.03.2012 in the city of Frankfurt/Main, Germany.
Results: Twenty four patients with IVDU underwent renal biopsy because of progressive chronic kidney disease or proteinuria. Renal AA-amyloidosis was the predominant cause of renal failure in 50% of patients. Membranoproliferative glomerulonephritis (GN) was the second most common cause found in 21%. Patients with AA-amyloidosis were more likely to be HIV infected (67 vs.17%; p=0.036) and tended to have a higher rate of repeated systemic infections (92 vs. 50%; p=0.069). Patients with AA-amyloidosis presented with progressive renal disease and nephrotic-range proteinuria but most patients had no peripheral edema or systemic hypertension. Development of proteinuria preceded the decline of GFR for approximately 1--2 years.
Conclusions: AA-amyloidosis was the predominant cause of progressive renal disease in the last 10 years in patients with IVDU. The highest rate of AA-amyloidosis observed was seen in HIV infected patients with IVDU. We speculate that chronic HIV-infection as well as the associated immunosuppression might promote development of AA-amyloidosis by increasing frequency and duration of infections acquired by IVDU
THE 4550 {\AA} BAND SYSTEM OF GLYOXAL
No full textAuthor Institution: Division of Pure Physics, National Research Council“Approximately 45 bands of glyoxal in the region 4000-4660 {\AA} have been photographed in absorption using a 30 ft. Ebert spectrograph with a resolving power of and a dispersion of 1.3 {\AA}/cm. The (0-0) baud near 4550 {\AA}, which WAS studied at a temperature of C, shows fairly well-resolved J- and K- structure characteristic of a perpendicular hand of a near symmetric top molecule. The rotational and vibrational analysis of the speetrum will be discussed.
THE ANALYSIS OF FIVE ELECTRONIC EMISSION SYSTEMS OF NIOBIUM NITRIDE (NbN) IN THE REGION 5000{\AA} – 6200{\AA}
No full textK. H. Rao and T. M. Dunn, Nature 222, 266 (1969). J. L. Femenias, C. Athenour, and T. M. Dunn, J. Chem. Phys. 63, 2861 (1975).Author Institution:Niobium nitride emission systems have been found at 5l37{\AA}, 5582{\AA}, 5740{\AA}, 5840{\AA}, 5860{\AA}, in addition to the already systems with subbands at 5930{\AA}, 6043{\AA}, and 6192{\AA}. Most of These systems show marked nuclear hyperfine structure of the rotational lines add this has been of assistance in the analysis of all of the systems. Systems of triplet-triplet, singlet-singlet and singlet-triplet are all present and the hyperfine structure also allows assignment of the ground and excited state electron configuration to be made with some confidence
Long-term biases in geomagnetic <i>K</i> and <i>aa</i> indices
No full textAnalysis is made of the geomagnetic-activity aa index and its source
K-index data from groups of ground-based observatories in Britain, and
Australia, 1868.0–2009.0, solar cycles 11–23. The K data show persistent
biases, especially for high (low) K-activity levels at British (Australian)
observatories. From examination of multiple subsets of the K data we infer
that the biases are not predominantly the result of changes in observatory
location, localized induced magnetotelluric currents, changes in magnetometer
technology, or the modernization of K-value estimation methods. Instead,
the biases appear to be artifacts of the latitude-dependent scaling used to
assign K values to particular local levels of geomagnetic activity. The
biases are not effectively removed by weighting factors used to estimate
aa. We show that long-term averages of the aa index, such
as annual averages, are dominated by medium-level geomagnetic activity levels
having K values of 3 and 4
Sigurd Aa. Aarnes in memoriam
No full textSigurd Aa. Aarnes in memoriamBy K. E. BuggeK. E. Bugge’s obituary for Sigurd Aa. Aarnes, professor of history and literary scholar, University of Bergen, lays weight upon his contributions in three areas: historiography in his doctoral thesis Grundtvig’s view of history and his view of life from 1961 with its structural analysis of the two-worlds motif, literary history with a special interest in shared Danish-Norwegian literature, and identityhistory with researches into Norwegian nation-building especially after 1814. Aarnes also collaborated in planning of the historical section of the forthcoming German translation of Grundtvig, and left among his papers a completed manuscript of a textual-critical edition of Bjørnson’s story Synnøve Solbakken
Structure of a rare non-standard sequence k-turn bound by L7Ae protein
No full textKt-23 from Thelohania solenopsae is a rare RNA kink turn (k-turn) where an adenine replaces the normal guanine at the 2n position. L7Ae is a member of a strongly conserved family of proteins that bind a range of k-turn structures in the ribosome, box C/D and H/ACA small nucleolar RNAs and U4 small nuclear RNA. We have solved the crystal structure of T. solenopsae Kt-23 RNA bound to Archeoglobus fulgidus L7Ae protein at a resolution of 2.95 Å. The protein binds in the major groove displayed on the outer face of the k-turn, in a manner similar to complexes with standard k-turn structures. The k-turn adopts a standard N3 class conformation, with a single hydrogen bond from A2b N6 to A2n N3. This contrasts with the structure of the same sequence located in the SAM-I riboswitch, where it adopts an N1 structure, showing the inherent plasticity of k-turn structure. This potentially can affect any tertiary interactions in which the RNA participates. © The Author(s) 2014. Published by Oxford University Press</p
The relation of the ratios of the specific growth rates (µ′/µ′′) to the ratios of the peptide chain elongation rates (<i>ε</i>′<sub>aa(k)</sub>/<i>ε</i>′′<sub>aa(k)</sub>) of ribosomal proteins.
No full text<p>Values of (<i>ε</i>′<sub>aa(k)</sub>/<i>ε</i>′′<sub>aa(k)</sub>) were evaluated using equation (9), <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059883#pone-0059883-t002" target="_blank">Table 2</a>. The plot is linear when µ′>µ′′ (see equation (11b), <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059883#pone-0059883-t002" target="_blank">Table 2</a>). The reference point (µ′/µ′′) = (<i>ε</i>′<sub>aa(k)</sub>/<i>ε</i> ′′<sub>aa(k)</sub>) = 1.0 is shown as a square; the open circles refer to BCG-Pasteur and Msmeg; the filled circle refers to <i>E. coli</i> B/r (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059883#pone-0059883-t003" target="_blank">Table 3</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0059883#pone.0059883-Bremer1" target="_blank">[19]</a>). The broken line applies when µ′< µ′′.</p
COLLISIONAL DEACTIVATION OF THE 3427 {\AA} VIBRATIOWAL BAND OF THE 3460 - 3015 {\AA} BAND SYSTEM OF BY VARIOUS INERT GASES
No full text J. B. Tellinghuisen, Ph.D. thesis, p. 152. University of California, Berkeley, California, 1969. ""Author Institution: Sandia LaboratoriesThe 3460 - 3015 {\AA} band system of has been tentatively to the transition of . In the course of investigating this system as a candidate for an e-beam initiated laser the collision deactivation rates of the 3427 {\AA} vibrational band by argon and krypton were measured. In addition, the collisional deactivation rate of the 3427 {\AA} vibrational band by ground state was measured and an estimate of the Lifetime of the upper state of the 3427 {\AA} transition was obtained
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