Microdeformation in Vredefort rocks; evidence for shock metamorphism

Planar microdeformations in quartz from basement or collar rocks of the Vredefort Dome have been cited for years as the main microtextural evidence for shock metamorphism in this structure. In addition, Schreyer describes feldspar recrystallization in rocks from the center of the Dome as the result of transformation of diaplectic glass, and Lilly reported the sighting of mosaicism in quartz. These textural observations are widely believed to indicate either an impact or an internally produced shock origin for the Vredefort Dome. Two types of (mostly sub) planar microdeformations are displayed in quartz grains from Vredefort rocks: (1) fluid inclusion trails, and (2) straight optical discontinuities that sometimes resemble lamellae. Both types occur as single features or as single or multiple sets in quartz grains. Besides qualitative descriptions of cleavage and recrystallization in feldspar and kinkbands in mica, no further microtextural evidence for shock metamorphism at Vredefort has been reported to date. Some 150 thin sections of Vredefort basement rocks were re-examined for potential shock and other deformation effects in all rock-forming minerals. This included petrographic study of two drill cores from the immediate vicinity of the center of the Dome. Observations recorded throughout the granitic core are given along with conclusions

Clinical presentation and outcome of pediatric ANCA-associated glomerulonephritis

Background Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a small- and medium-sized vasculitis classically seen in adult patients, with peak onset near the fifth to seventh decade of life. There is little data on ANCA-associated vasculitis in pediatric patients, and most studies have limited follow-up. Methods This is a retrospective chart review of 22 patients with ANCA-positive glomerulonephritis in a single institution from 1991 to 2013. Results Of the 22 patients, eight (36 %) required renal replacement therapy (RRT) at diagnosis; four of these patients recovered sufficient renal function to initially discontinue dialysis. Five patients (23 %) were treated with plasmapheresis at presentation. The median time from presentation until first clinical or serologic relapse was 1.7 ± 1.2 years. After a median follow-up of 5.8 years, just over half of our patients had chronic kidney disease (CKD) stages 1–3 (55 %). Seven (32 %) patients progressed to end-stage renal disease (ESRD) and eventually required kidney transplant. Conclusion ANCA-associated glomerulonephritis is a rare disorder in children. Presentation and outcomes vary significantly among patients. More research is required to follow these patients who are diagnosed in childhood to further characterize the long-term outcome of the disease

Genetic control of seed dormancy and pre-harvest sprouting in wheat.

Pre-harvest sprouting (PHS) damage leads to occasional massive losses in all wheat producing areas, causing downgrading of grain quality, that severely limits' end-use applications and results in ;substantial financial losses to farmers and food processors. Red grain color is a traditional marker for,:resistance to sprouting in wheat breeding programs, however red-grained genotype alone does not always guarantee effective resistance. The objective of this work was to find genes for resistance to PHS and investigate its inheritance in Brazilian wheat cultivars. Genetic variation for dormancy was investigated in :the parents, F 1 and 300 F 2 lines derived from the cross Frontana x OR1 and its reciprocal. The germination/ dormancy sprouted grains was evaluated ,on fifty seeds per replication, germinated in paper towel rolls at woC for 5 days. A bimodal distribution for dormancy occurred in the Frontana/OR1 and OR1/Frontana ierived F 2 populations. The mean ratio of dormant and non-dormant seeds of the cross and its reciprocal was 85: 1115, fitting a digeAi~ model of 1: 15 (P < 0.05). In fact, all non after-ripened F 1 seeds germinated. The F2 distribution indicates that two major genes, here calledA,a andB,b, control seed dormancy, which ,It appears to be recessive to dormancy. Only the homozygous aabb is dormant. As expected, there was no . 'effect of maternal tIssues

Oligodendroglioma cells lack glutamine synthetase and are auxotrophic for glutamine, but do not depend on glutamine anaplerosis for growth

In cells derived from several types of cancer, a transcriptional program drives high consumption of glutamine (Gln), which is used for anaplerosis, leading to a metabolic addiction for the amino acid. Low or absent expression of Glutamine Synthetase (GS), the only enzyme that catalyzes de novo Gln synthesis, has been considered a marker of Gln-addicted cancers. In this study, two human cell lines derived from brain tumors with oligodendroglioma features, HOG and Hs683, have been shown to be GS-negative. Viability of both lines depends from extracellular Gln with EC of 0.175 ± 0.056 mM (Hs683) and 0.086 ± 0.043 mM (HOG), thus suggesting that small amounts of extracellular Gln are sufficient for OD cell growth. Gln starvation does not significantly affect the cell content of anaplerotic substrates, which, consistently, are not able to rescue cell growth, but causes hindrance of the Wnt/β-catenin pathway and protein synthesis attenuation, which is mitigated by transient GS expression. Gln transport inhibitors cause partial depletion of intracellular Gln and cell growth inhibition, but do not lower cell viability. Therefore, GS-negative human oligodendroglioma cells are Gln-auxotrophic but do not use the amino acid for anaplerosis and, hence, are not Gln addicted, exhibiting only limited Gln requirements for survival and growth

A comprehensive study of noble gases and nitrogen in Hypatia, a diamond-rich pebble from SW Egypt

This is a follow-up study of a work by Kramers et al. (2013) on an unusual diamond-rich rock found in the SW side of the Libyan Desert Glass strewn field. This pebble, called Hypatia, is composed of almost pure carbon. Transmission Electron Microscopy and X-ray diffraction results reveal that Hypatia is made of defect-rich diamond containing lonsdaleite and deformation bands. These characteristics are compatible with an impact origin on Earth and/or in space. We analyzed concentrations and isotopic compositions of all five noble gases and nitrogen in several mg sized Hypatia samples. These data confirm that Hypatia is extra-terrestrial. The sample is rich in trapped noble gases with an isotopic composition close to the meteoritic Q component. 40Ar/36Ar ratios in individual steps are as low as 0.4. Concentrations of cosmic-ray produced 21Ne correspond to a nominal cosmic-ray exposure age of ca. 0.1 Myr if produced in a typical m-sized meteoroid. Such an atypically low nominal exposure age suggests high shielding in a considerably larger body. In addition to the Xe-Q composition, an excess of radiogenic 129Xe (from the decay of extinct 129I) is observed (129Xe/132Xe = 1.18 +/- 0.03). Two N components are present, an isotopically heavy component ({\delta}15N = +20 permil) released at low temp. and a major light component ({\delta}15N = -110 permil) at higher temp. This disequilibrium in N suggests that the diamonds in Hypatia were formed in space. Our data are broadly consistent with concentrations and isotopic compositions of noble gases in at least three different types of carbon-rich meteoritic materials. However, Hypatia does not seem to be related to any of these materials, but may have sampled a similar cosmochemical reservoir. Our study does not confirm the presence of exotic noble gases that led Kramers et al. to propose that Hypatia is a remnant of a comet that impacted the Earth

Porphyria cutanea tarda in an HCV-positive liver transplant patient: a case report

Introduction. Porphyria cutanea tarda (PCT) is the most common type of porphyria. The strong association between PCT and hepatitis C virus (HCV) infection is well established. Although antiviral treatment of chronic hepatitis C may improve PCT in some cases, de novo onset of PCT has been observed in patients undergoing peginterferon/ribavirin treatment. We present a rare case of a genotype 3 HCV-positive liver transplant recipient who developed PCT during antiviral treatment and discuss its probable etiopathogenesis. Case presentation. A genotype 3 HCV-positive liver transplant recipient, a 42-year-old man, was treated with peginterferon alfa-2a (180 µg/week) combined with ribavirin (1,200 mg/day) for recurrence of HCV infection after liver transplantation. He presented with hyperferritinemia but tested negative for genetic hemochromatosis (C282Y and H63D mutations). During antiviral therapy, he developed skin lesions on his hands characterized by vesicles and erosions consistent with PCT. PCT was confirmed by skin biopsy and elevated urinary uroporphyrin levels (1,469 mg/24 h). He was treated with chloroquine (200 mg) twice weekly, resulting in gradual regression of the skin lesions. Antiviral treatment was stopped after 48 weeks, and the patient achieved a sustained virological response. In conclusion, we report an extremely rare case of PCT in a genotype 3 HCV-positive liver transplant patient treated with antiviral therapy. We believe that the combination of HCV genotype 3 infection; hemolysis due to ribavirin treatment; and increased plasma levels of cytokines, such as IL-6 and TNFα, could have altered the patient's iron metabolism and thus caused PCT

Qualidade da semente e densidade de semeadura no estabelecimento e na produtividade do milho.

Uma das principais causas da baixa produtividade de milho é a qualidade da semente, que afeta o estande inicial, o vigor das plantas, e conseqüentemente, a produtividade. O objetivo deste trabalho foi determinar o efeito da qualidade da semente e a densidade de semeadura no estabelecimento e na produtividade de milho. Quatro lotes de sementes de milho BRS 201, com germinação de 95%, 90%, 85% e 75%, foram semeados em três densidades de semeadura: 50, 60 e 70 mil sementes/ha, nos anos de 1996/97 e 1997/98. A baixa qualidade da semente provocou reduções acentuadas na emergência de campo, no número de plantas e, conseqüentemente, na produtividade do milho BRS 201.O aumento da densidade de 50 para 70 mil sementes/ha, na semeadura, não compensou a redução da qualidade da semente. Para o acréscimo de 15% na germinação, foi observado, em média, um ganho de produtividade de 30%. Com base nos resultados destes trabalho, recomenda-se aos produtores de milho a utilização de lotes de sementes com germinação superior a 90% e densidade de semeadura entre 50 e 60 mil sementes/ha.bitstream/CNPMS/15812/1/Bol_01.pd