Sampling and analyzing metals in soils for archaeological prospection: a critique

This paper presents a critique of current methods of sampling and analyzing soils for metals in archaeological prospection. Commonly used methodologies in soil science are shown to be suitable for archaeological investigations, with a concomitant improvement in their resolution. Understanding the soil-fraction location, concentration range, and spatial distribution of autochthonous (native) soil metals is shown to be a vital precursor to archaeological-site investigations, as this is the background upon which anthropogenic deposition takes place. Nested sampling is suggested as the most cost-effective method of investigating the spatial variability in the autochthonous metal concentrations. The use of the appropriate soil horizon (or sampling depth) and point sampling are critical in the preparation of a sampling regime. Simultaneous extraction is proposed as the most efficient method of identifying the location and eventual fate of autochthonous and anthropogenic metals, respectively.

Observations of supercooling and frazil ice formation in the Laptev Sea coastal polynya

This paper examines a hydrographic response to the wind‐driven coastal polynya activity over the southeastern Laptev Sea shelf for April–May 2008, using a combination of Environmental Satellite (Envisat) advanced synthetic aperture radar (ASAR) and TerraSAR‐X satellite imagery, aerial photography, meteorological data, and SBE‐37 salinity‐temperature‐depth and acoustic Doppler current profiler land‐fast ice edgemoored instruments. When ASAR observed the strongest end‐of‐April polynya event with frazil ice formation, the moored instruments showed maximal acoustical scattering within the surface mixed layer, and the seawater temperatures were either at or 0.02°C below freezing. We also find evidence of the persistent horizontal temperature and salinity gradients across the fast ice edge to have the signature of geostrophic flow adjustment as predicted by polynya models.

Effect of asparaginase on flavour formation in roasted coffee

The use of asparaginase, an enzyme that hydrolyses the acrylamide precursor asparagine into aspartic acid and ammonia, is seen as a promising procedure to mitigate the formation of the potential human carcinogen acrylamide in food products, without compromising desirable sensory qualities. This study examines the effect of asparaginase treatment on the asparagine and aspartic acid content of green coffee beans prior to roasting as well as the impact on the formation of acrylamide and thermally generated aroma compounds in roasted coffee

Arrest of root formation in a permanent maxillary central incisor subsequent to trauma and pulp necrosis to the primary predecessor

This paper reports a case in which a previous traumatic injury at the age of 2 and pulp necrosis to a primary incisor resulted in a rare injury to the permanent successor tooth. The radiographic examination at the age of 9 showed the arrest of root formation of the permanent maxillary right central incisor, which did not erupt. Tooth 11 was extracted and a functional removable space maintainer was prepared. At the age of 17, the patient received an anterior fixed prosthesis for re-establishment of the esthetics, phonetics and deglutition.

Potential sites of triple-helical nucleic acid formation in chromosomes of Rhynchosciara (Diptera: Sciaridae) and Drosophila melanogaster

Antibodies to specific nucleic acid conformations are amongst the methods that have allowed the study of non-canonical (Watson-Crick) DNA structures in higher organisms. In this work, the structural limitations for the immunological detection of DNA.RNA hybrid duplexes were examined using specific RNA homopolymers as probes for homopolymer polydeoxyadenylic acid (poly(dA)).polydeoxythymidylic acid (poly(dT))-rich regions of Rhynchosciara americana (Diptera: Sciaridae) chromosomes. Anti-DNA.RNA duplexes did not react with the complex formed between chromosomal poly(dA) and exogenous polyuridylic acid (poly(rU)). Additionally, poly(rU) prevented the detection of polyadenylic acid.poly(dT) hybrid duplexes preformed in situ. These results raised the possibility that three-stranded structures rather than duplexes were formed in chromosomal sites. To test this hypothesis, the specificity of antibodies to triple-helical nucleic acids was reassessed employing distinct nucleic acid configurations. These antibodies were raised to the poly(dA).poly(rU).poly(rU) complex and have been used here for the first time in immunocytochemistry. Anti-triplex antibodies recognised the complex poly(dA).poly(rU).poly(rU) assembled with poly(rU) in poly(dA).poly(dT)-rich homopolymer regions of R. americana chromosomes. The antibodies could not detect short triplex stretches, suggesting the existence of constraints for triple-helix detection, probably related to triplex tract length. In addition, anti-poly(dA).poly(rU).poly(rU) antibodies reacted with the pericentric heterochromatin of RNase-treated polytene chromosomes of R. americana and Drosophila melanogaster. In apparent agreement with data obtained in cell types from other organisms, the results of this work suggest that significant triple-helix DNA extensions can be formed in pericentric regions of these species.

Cell death and lumen formation in spheroids of MCF-7 cells

3D (three-dimensional) cell culture permits a more integrated analysis of the relationship between cells, inserting them into a structure more closely resembling the cellular microenvironment in vivo. The development of in vitro parameters to approximate in vivo 3D cellular environments makes a less reductionist interpretation of cell biology possible. For breast cells, in vitro 3D culture has proven to be an important tool for the analysis of luminal morphogenesis. A greater understanding of this process is necessary because alterations in the lumen arrangement are associated with carcinogenesis. Following lumen formation in 3D cell culture using laser scanning confocal microscopy, we observed alterations in the arrangement of cytoskeletal components (F-actin and microtubules) and increasing levels of cell death associated with lumen formation. The formation of a polarized monolayer facing the lumen was characterized through 3D reconstructions and the use of TEM (transmission electron microscopy), and this process was found to occur through the gradual clearing of cells from the medullary region of the spheroids. This process was associated with different types of cell death, such as apoptosis, autophagy and entosis. The present study showed that changes in the extracellular matrix associated with long periods of time in 3D cell culture lead to the formation of a lumen in MCF-7 cell spheroids and that features of differentiation such as lumen and budding formation occur after long periods in 3D culture, even in the absence of exogenous extracellular compounds.

Role of MMP9 on Invadopodia Formation in Cells From Adenoid Cystic Carcinoma. Study by Laser Scanning Confocal Microscopy

Migration, invasion and protease activity are essential for tumor progression and metastasis. Metastatic cells rely on invadopodia to degrade and invade extracellular matrix (ECM). Invadopodia are membrane protrusions with enzymes required for ECM degradation. These protrusions contain cortactin and membrane type I matrix metalloproteinase (MT1-MMP) superimposed to areas of digested matrix. Here we characterized invadopodia in a cell line (CAC2) derived from human adenoid cystic carcinoma. We carried out fluorescent-substrate degradation assay to assess in situ protease activity of CAC2 cells. Digestion spots in fluorescent substrate appear as black areas in green background. Cells were cultured on Matrigel-gelatin-FITC and fixed after 1 h and 3 h. CAC2 cells were double labeled to actin and cortactin. Cells were also double stained to actin and MT1-MMR Samples were studied by laser scanning confocal microscopy. In all time points CAC2 cells showed actin, cortactin, and MT1-MMP colocalized with digestion spots in fluorescent substrate. We searched for other proteases involved in invadopodia activity. We have previously demonstrated that MMP9 influences adenoid cystic carcinoma behavior. This prompted us to investigate role played by MMP9 on invadopodia formation. CAC2 cells had MMP9 silenced by siRNA. After I h in fluorescent substrate, cells with silenced MMP9 showed clear decrease in matrix digestion compared with controls. No differences were found in cells with silenced MMP9 grown for 3 h on fluorescent substrate. Our results showed that CAC2 cells exhibit functional invadopodia containing cortactin and MT1-MMR Furthermore, MMP9 would be required in the initial steps of invadopodia formation. Microsc. Res. Tech. 73:99-108, 2010. (C) 2009 Wiley-Liss, Inc.

Gamma-linolenic Acid Alters Ku80, E2F1, and Bax Expression and Induces Micronucleus Formation in C6 Glioma Cells In Vitro

Gamma-linolenic acid (GLA) is an inhibitor of tumor cell proliferation in both in vitro and in vivo conditions. The aim of this study was to investigate the effects of 150 mu M GLA on the expression of E2F1, cyclin D1, bax, bcl2, Ku70, and Ku80 in C6 rat glioma cells. The Ku proteins were chosen as previous studies have shown that loss or reduction in their expression causes increased DNA damage and micronucleus formation in the presence of radiation. The fact that GLA exposure is known to enhance the efficacy of radiation treatment raised the question whether the Ku proteins could be involved in this effect as seen for other molecules such as roscovitine and flavopiridol. GLA altered the mRNA expression of E2F1, cyclin D1, and bax, but no changes were found for bcl2, Ku70, and Ku80. Alterations in protein expression were observed for bax, Ku80, and E2F1. The 45% decrease in E2F1 expression was proportional to decreased cell proliferation (44%). Morphological analysis found a 25% decrease in mitotic activity in the GLA-treated cells, which was accompanied by a 49% decrease in S-phase by FACS analysis. A 39% increase in the number of micronuclei detected by Hoechst fluorescence points to GLA`s effects on cell division even at concentrations that do not produce significant increases in apoptosis. Most important was the finding that Ku80 expression, a critical protein involved in DNA repair as a heterodimer with Ku70, was decreased by 71%. It is probable that reduced Ku80 is responsible for the increase in micronucleus formation in GLA-treated cells in a similar manner to that found in Ku80 null cells exposed to radiation. The decreased expression of Ku80 and E2F1 could make cells more susceptible to radiotherapy and chemotherapy. (C) 2009 IUBMB

Conformational behavior of different possible ways of oligoglycine formation in a solvent-free environment

The possible ways for glycine oligopeptide formation in gas phase, both in the extended P-strand like conformation and folded 2(7)-ribbon like conformations are analyzed using quantum chemical calculations. We focus on the sequential formation of peptide bond through upgradation of the immediate lower order molecule and observe the consequences in other related processes like oligoglycine formation through simultaneous peptide linkage of n glycine monomers and interchange of molecular conformation through peptide linkage. A comparison is made between the structures and binding energies obtained for both conformers. All binding energies are increased by the zero-point energy contribution. The role of electron correlation effects is briefly analyzed. The folded 2(7)-ribbon-like conformations in vacuo are found to be more stable in comparison to the extended structure. (c) 2007 Elsevier B.V. All rights reserved.

Shock wave formation in hot nuclear matter

Assuming that nuclear matter can be treated as a perfect fluid, we study the propagation of perturbations in the baryon density at high temperature. The equation of state is derived from the non-linear Walecka model. The expansion of the Euler and continuity equations of relativistic hydrodynamics around equilibrium configurations lead to the breaking wave equation for the density perturbation. We solve it numerically for this perturbation and follow the propagation of the initial pulses.

Rock magnetism in soils of the Pampean plain. Buenos Aires province, Argentina. Linking climate and magnetic behaviour

Results of the study of Argiudolls in two localities (Zarate and Veronica) of the Pampean plain, Argentina, are presented in this contribution. This is a typical area covered by loess. The magnetic studies carried out allowed to determine the presence of detrital magnetite and titanomagnetite, as well as maghemite, pedogenic goethite and superparamagnetic particles (SP). In Veronica soils, a depletion of ferromagnetic minerals is recorded The dominant process in these soils has been the reductive loss of detrital magnetite and titanomagnetite. This is associated with a greater degree of evolution of the soil, which is determined by the concentration and type of detected clays. The higher clay concentration in these soils facilitated reducing conditions and a greater loss of detrital magnetic particles. The loss is reinforced under poor drainage conditions. In the poorly drained soil of Zarate, a concentration of magnetic particles is observed in the Bt horizon, which is associated with an illuviation process. The well drained soil of the same locality shows neoformation of SP particles. These particles would have an ephemeral life until a new wet period in the annual cycle occurs. Although some characteristics of the magnetic signal appear reinforced by the conditions of drainage, this aspect does not seem to be too significant, at least in the Pampean region with low topographic gradients.

Lycopodiopsis derbyi Renault from the Corumbatai Formation in the state of Sao Paulo (Guadalupian of Parana Basin, Southern Brazil): New data from compressed silicified stems

Lycopodiopsis derbyi Renault was analyzed on the basis of compressed silicified stems from four Guadalupian outcrops of the Parana Basin (Corumbatai Formation) in the State of Sao Paulo, Southern Brazil. Dichotomous stems have been recorded, and three different branch regions related to apoxogenesis are described. The most proximal region has larger, clearly rhomboidal leaf cushions, with protruding upper edges; the intermediate transitional region also has rhombic leaf cushions, but they are smaller and less elongated than the lower in the same axis; finally, the most distal region reveals only incipient cushions, with inconspicuous infrafoliar bladders; interspersed microphylls were still attached. A well preserved branch representative of this most distal region was sectioned; it has a siphonostelic cylinder similar to that previously described for L derbyi. The cortex, however, shows new traits, such as a short portion of elongated cells between the periderm and the external cortex (or leaf cushion tissue). The stems were apparently silicified prior to their final burial but were probably not transported for long distances. Their final burial may have taken place during storm events, which were common during the deposition of the Corumbatai Formation. These stems are commonly deformed due to compression, mainly because the internal cortical portions rapidly decayed prior to silicification due to their thin-walled tissue, and are therefore not preserved. The common alkalinity of a shallow marine environment such as that in which the Corumbatai Formation was deposited, should mobilize the silica and favors petrifaction. Based on the new data, an emended diagnosis is proposed and a modification of the identification key published by Thomas and Meyen in 1984 for Upper Paleozoic Lycopsida is suggested. (C) 2009 Elsevier B.V. All rights reserved.

Petrology and geochemistry of the banded iron formation in the Eastern Sierras Pampeanas of San Luis (Argentina): Implications for the evolution of the Nogoli Metamorphic Complex

The metamorphosed banded iron formation from the Nogoli Metamorphic Complex of western Sierra de San Luis, Eastern Sierras Pampeanas of Argentina (Nogoli area, 32 degrees 55`S-66 degrees 15`W) is classified as an oxide facies iron formation of Algoma Type, with a tectonic setting possibly associated with an island arc or back arc, on the basis of field mapping, mineral and textural arrangements and whole rock geochemical features. The origin of banded iron formation is mainly related to chemical precipitation of hydrogenous sediments from seawater in oceanic environments. The primary chemical precipitate is a result of solutions that represent mixtures of seawater and hydrothermal fluids, with significant dilution by maficultramafic volcanic and siliciclastic materials. Multi-stage T(DM) model ages of 1670, 1854 and 1939 Ma and positive, mantle-like xi Nd((1502)) values of +3.8, +1.5 and +0.5 from the banded iron formation are around the range of those mafic to ultramafic meta-volcanic rocks of Nogoli Metamorphic Complex, which are between 1679 and 1765 Ma and +2.64 and +3.68, respectively. This Sm and Nd isotopic connection suggests a close genetic relationship between ferruginous and mafic-ultramafic meta-volcanic rocks, as part of the same island arc or back arc setting. A previous Sm-Nd whole rock isochron of similar to 1.5 Ga performed on mafic-ultramafic meta-volcanic rocks led to the interpretation that chemical sedimentation as old as Mesoproterozoic is possible for the banded iron formation. A clockwise P-T path can be inferred for the regional metamorphic evolution of the banded iron formation, with three distinctive trajectories: (1) Relict prograde M(1)-M(3) segment with gradual P and T increase from greenschist facies at M(1) to amphibolite facies at M(3). (2) Peak P-T conditions at high amphibolite-low granulite facies during M(4). (3) Retrograde counterpart of M(4), that returns from amphibolite facies and stabilizes at greenschist facies during M(5). Each trajectory may be regarded as produced by different tectonic events related to the Pampean? (1) and the Famatinian (2 and 3) orogenies, during the Early to Middle Paleozoic. The Nogoli Metamorphic Complex is interpreted as part of a greenstone belt within the large Meso- to Neoproterozoic Pampean Terrane of the Eastern Sierras Pampeanas of Argentina. (C) 2009 Elsevier Ltd. All rights reserved.