Enriched Areas Research Articles

Factors affecting retention of nutrients and organic matter in stormwater ponds

AbstractStormwater ponds are a common way to handle urban runoff. Different pond designs have been tested for decades to retain as much water as possible. Lately also, retention of nutrients and organic matter has become increasingly important, to reduce the eutrophication of downstream aquatic systems and thereby, e.g. fulfil the European Water Framework Directive. We have examined the load of particulate and dissolved fractions of organic matter, phosphorus, nitrogen and iron in 66 Danish ponds to determine the importance of catchment type (66 ponds) and the retention efficiency of the ponds (39 ponds) dependent on their type, age, size and design. The results showed that discharge from nutrient enriched and industrial areas is the most polluted while urban and developing areas are the least polluted. Wet ponds combined with vegetated sand filters have higher retentions of the particulate fractions (40–80%) compared with traditional wet ponds (10–20%). Generally, optimized retention requires a ratio between pond volume and impermeable catchment area of >250 m3 red.ha (reduced or impermeable hectare). Young ponds have higher retention than older ones, especially regarding the particulate fractions of organic matter, phosphorus and nitrogen. Here, 40–50% is retained in ponds <5 years, 0–30% in 5–10‐year‐old ponds and almost nothing in ponds >10 years. For the dissolved fractions, the trend is the same, but with lower retentions. Therefore, management and maintenance should be considered for all ponds, to avoid problems of internal loading, filling and resuspension. Copyright © 2015 John Wiley & Sons, Ltd.

Controlling conditions for synthesis of iron-titanium carbide using two different titanium precursors

Preparation of Fe–TiC composite from mixtures of carbon black and two different titanium bearing minerals (black sand ilmenite and natural rutile) was studied. Milled (mechanically activated) and unmilled carbon containing mixtures were prepared and then heated at temperatures 1200°C and 1300°C for 3h under an inert atmosphere. The reaction progress, as well as reaction products, was evaluated using thermogravimetric analysis (TGA-DTA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX). The feasibility of producing Fe–TiC composites from titanium bearing materials mixed with carbon black was proved. Fe–TiC could be produced by carbothermic reduction of mechanically activated black sand ilmenite containing mixtures milled for 50h and heated up to 1200°C. On the other hand, 60h milling followed by heating up to 1300°C was needed in case of natural rutile containing mixture. The morphology of the Fe–TiC produced from black sand ilmenite showed a homogeneous distribution of Fe and TiC enriched areas, while the Fe–TiC produced from natural rutile showed intense distribution of TiC phase with traces of iron and lower titanium oxide.

Application of Short-Offset TEM (SOTEM) Technique in Mapping Water-Enriched Zones of Coal Stratum, an Example from East China

Water inrush from limestone coal beds is disastrous for coal mining. In general, it is very difficult to detect such water-enriched zones because of their relatively large burial depth. In this paper, we propose a novel transient electromagnetic method (TEM) configuration, short-offset transient electromagnetic method (SOTEM). Consistency of the results obtained from SOTEM measurements in the Shandong province, East China and drilling information indicate that the proposed TEM configuration not only improves the accuracy, but also enlarges the exploration depth for detecting water-enriched areas in coal mines ranging from 1,000 to 1,200 m depth. In this region, a majority of the deep coal beds are filled with water. The SOTEM technique was successfully employed in detecting the floor of a coal seam at a depth of about 1,500 m, as well as in identifying the location of the water-saturated area. These findings were later confirmed by subsequent drillings. Thus, our study indicates that SOTEM represents a convenient and effective technique for deep mineral and hydrogeological investigations due to its high sensitivity to conductive zones (water enriched areas) and vertical resolution.

Chromium enrichment on the habit plane of dislocation loops in ion-irradiated high-purity Fe–Cr alloys

Reduced activation high-chromium ferritic/martensitic steels are candidate materials for Generation IV fission and fusion reactors. To gain knowledge about the radiation resistance of these steels in such environments, the first step is to study the Fe–Cr matrix of this material. For that purpose and to understand ballistic damage by neutrons, self-ion irradiations, with and without simultaneous He injection, were performed on a series of high-purity Fe–Cr binary alloys at 773K. Transmission electron microscopy (TEM) analysis revealed “displacement fringe contrast” inside the dislocation loops. This was attributed to the presence of Cr-enriched zones on their habit plane, which is a defect-free region for body-centered cubic Fe-based alloys. A plausible mechanism is discussed to explain the phenomenon, the first step of which would be the radiation-induced segregation of Cr atoms on the dislocation loop core. Energy-dispersive X-ray spectroscopy in scanning TEM mode and atom probe tomography (APT) gave a coherent quantitative estimate of the Cr concentration in these enriched areas. APT study showed that the enrichment was heterogeneous on the loop plane. Upon in situ annealing up to 900K, the loops and the fringes disappeared completely, without leaving a secondary-phase particle, such as carbide, at their position. Fringes were present until the loop disappeared.

Physiological and biochemical responses of the Polychaete Diopatra neapolitana to organic matter enrichment

Several studies have demonstrated that organic matter enrichment may be associated to aquaculture, leading to impoverished benthic communities and species succession with loss of biodiversity, but very few studies have investigated biochemical and physiological alterations that species affected by aquaculture activities undergo. Thus, in the present study, the effects of the organic enrichment originating from an oyster culture were studied in the Polychaete Diopatra neapolitana, a species already shown to be sensitive to inorganic contamination. For this, physiological responses and biochemical alterations were evaluated. The results obtained revealed that individuals from highly organically enriched areas presented lower capacity to regenerate their body but higher glycogen and protein levels. Furthermore, with increasing organic matter D. neapolitana increased the lipid peroxidation (LPO), the oxidized glutathione content (GSSG) and Glutathione S-transferase activity (GSTs) content, and the activity of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD). This study evidenced that organic matter enrichment induced biochemical and physiological alterations in D. neapolitana. Thus, this species was shown to be a good sentinel species to monitor organic contamination.

Estuarine macrofauna responses to continuous in situ nutrient addition on a tropical mudflat

A field experiment to assess the effects of continuous nutrient addition on the macrobenthic community was carried out on an estuarine mudflat on the northeast coast of Brazil. The experiment began on 5 October 2005 and ended on 8 February 2006. Macrofauna was compared at approximately four-week intervals in triplicate plots with three levels (Control – C, Low Dose – LD and High Dose – HD) of weekly fertilizer additions for 17weeks. Inorganic fertilizer (N–P–K) was applied on nine randomly defined quadrangular plots (4m2 each). All measurements were calculated from species abundances. Multivariate analyses as well as the univariate indices (richness, abundance and Shannon–Wiener index) showed statistically significant differences between the enriched and control areas during the period of the experiment. The expected gradual response based on the succession model of Pearson and Rosenberg was not observed. The nutrient doses used were high enough to cause severe decreases in abundance, richness and evenness, and an increase in dominance.

Tuning the ferromagnetic-antiferromagnetic interfaces of granular Co-CoO exchange bias systems by annealing

The low-temperature magnetic behavior of granular Co-CoO exchange bias systems, prepared by oxygen ion implantation in Co thin films and subsequent annealing, is addressed. The thermal activation effects lead to an O migration which results in virtually pure Co areas embedded in a structurally relaxed and nearly stoichiometric CoO phase. This yields decreased training and exchange bias shifts, while the blocking temperature significantly increases, coming close to the Néel temperature of bulk CoO for samples implanted to a fluence above 1 × 1017 ions/cm2 (15% O). The dependence of the exchange bias shift on the pristine O-implanted content is analogous to that of the antiferromagnetic thickness in most ferromagnetic/antiferromagnetic systems (i.e., an increase in the exchange bias shift up to a maximum followed by a decrease until a steady state is reached), suggesting that, after annealing, the enriched Co areas might be rather similar in size for samples implanted above 1 × 1017 ions/cm2, whereas the corresponding CoO counterparts become enlarged with pristine O content (i.e., effect of the antiferromagnet size). This study demonstrates that the magnetic properties of granular Co-CoO systems can be tailored by controllably modifying the local microstructure through annealing treatments.

Principle of Well-Net Design for Coalbed Methane Exploitation in Coal Mine Area

There are abundant CBM (Coalbed Methane) in China. These CBM has caused a remarkable problem to the coal-mining in China. In order to improve the structure of Chinese energy and eliminate the risk of coal mine gas, the relevant industries and sections have implemented many explorations in CBM enriched areas. With great achievements, there are many important problems in the actions of CBM exploitation. The disadvantageous interaction of the surface CBM well and the later coal mining has been ignored at all. There are many disadvantages and defects. To solve these problems and eliminate or weaken the disadvantageous, the scientific and reasonable design of surface CBM well location is an important step. With the thinking of surface condition, coal mining plan, the arrangement of coal mine laneway, the direction and scale of the in-situ stress, and thinking more about the negative influence to and of surface CBM well, according to the theories of mining dynamics, mining engineering, mining geomechanics, and the CBM engineering, the design theory of the surface CBM well net can be studied. Finally, the arrangement principle of CBM product well in coal field is presented. The existing or future coal pillar will be a critical location for the surface CBM well location.

Impact-induced compositional variations on Mercury

Remote sensing data suggest Mercury's surface has compositional variations spatially associated with crater and basin ejecta, the so-called “Low-Reflectance Material” (LRM), which has been suggested to be enriched in a subsurface native darkening agent that is excavated and redeposited onto the surface. This unit may record the evidence of impact-induced mixing of Mercury's outer layers during its early history. Here, we develop a fully three-dimensional Monte Carlo model of impact cratering, excavation, and ejecta blanket deposition on a global scale for Mercury.New dynamical simulations of the early evolution of the asteroid belt hint at the presence of additional asteroids in a region interior to the present-day belt, known as the “E-belt”. We use Monte Carlo methods to show that the predicted bombardment from this population matches the observed spatial crater densities on Mercury. Impacts large enough to pierce through the crust create surface ejecta deposits rich in mantle material. Later impacts onto enriched ejecta deposits redistribute mantle material away from the basins. For the suggested average mercurian crustal thickness of 50 km, the surface has, on average, ∼0.4% mantle material by volume; the most enriched areas have ∼30% mantle by volume.The regional coverage of impact-induced compositional changes is strongly dependent on the thickness to the subsurface source. Because observations indicate LRM covers ∼15% of Mercury's surface, our model suggests the darkening agent is ∼30 km deep. Considering the current estimated average mercurian crustal thickness of 50 km, this implies the darkening agent is likely located within a chemically distinct lower crust.

Clinical Utility of SNP Microarrays in Adult Brain Tumors: Molecular Insight into Tumor Heterogeneity and Progression

s 215 cases. In at least two cases, array testing provided information that would have been of major prognostic importance if available at the time of diagnosis. This data illustrates that whole genome arrays represent a suitable tool for the detection of prognostic genomic aberrations from FFPE material in MS, in a clinical diagnostic setting. High Resolution SNP Microarray Analysis is Useful for Diagnosis and Prognosis of Renal Epithelial Neoplasms Daynna J. Wolff , James S. Rosoff , Heidi H. Hamilton , M. Timothy Smith a Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA; Department of Urology, Medical University of South Carolina, Charleston, SC, USA Renal epithelial neoplasms (REN) are common in adults with approximately 54,000 newly diagnosed cases each year and over 13,000 deaths. Diagnosis and classification of REN can be difficult based uponhistologic and clinical information, however, the prediction of which patients will have recurrent disease and/or disease progression is even more challenging. Single nucleotide polymorphism (SNP) microarray analysis has been shown to be useful in stratifying the four major classes of REN for diagnosis into clear cell renal cell carcinoma (RCC), papillary RCC, chromophobe RCC and oncocytoma. The aim of this study was to determine if microarray analysis could also be useful for identifying markers associated with RCC cases with a high risk for recurrence and/or metastasis. High resolution SNP microarray (Illumina Omni-1) analysis was performed on 41 fresh renal tumors. An overall concordance rate of 83%was observed between the histologic and genetic classification confirming the utility of SNP analysis in the subclassification of REN. In addition, several genetic markers, including loss of 4q, 9/9p, 14 and 18, were associatedwith high-risk histologic features and with clinical data showing evidence of disease following nephrectomy and/or progression/metastasis. Amplificationsandchromothripsiswereonlyseen inRCCwith highrisk features. These studies show that SNP microarray genomic analysis can provide important prognostic information and could be useful to guide treatment for patients with RCC. Clinical Utility of SNP Microarrays in Adult Brain Tumors: Molecular Insight into Tumor Heterogeneity and Progression Iya Znoyko, Cynthia Welsh, Daynna Wolff Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, USA Each year in the US, there are approximately 23,000 newly diagnosed brain tumors and 14,000 related deaths. Somatic genetic abnormalities have been associated with histological subtype and grade of common adult brain tumors, gliomas and meningiomas. High resolution SNP microarray analysis could provide valuable information on genetic aberrations associated with brain tumors, assisting in stratification for prognosis and treatment. DNA from fresh brain tissue of 2 patients with high grade glioblastoma (WHO IV), 2 patients with low grade astrocytoma (WHO II and I), and a patient with meningioma (WHO I) was analyzed by Illumina SNP microarray; for two of above patients, FFPE samples were analyzed in parallel. Results were compared to histopathological studies. In all cases SNP microarray revealed results that correlated with histopathological diagnosis and for 4/5 cases, additional clinically relevant information was provided. Microarray results from two glioblastoma cases and one case of astrocytoma allowed for subtyping of the disease. The genetic aberrations observed in two cases with low grade tumors [meningioma (WHO I), astrocytoma (WHO II)] suggested potential progression to higher grade. Comparative analysis of both cases with fresh and fixed tissue samples from tumor enriched areas (one astrocytoma and one high grade glioma) revealed genetic heterogeneity. Our data demonstrate the feasibility of using high resolution SNP analysis for studies of adult brain tumors both on fresh and fixed tissue. Genetic profiling facilitates detailed stratification of tumors into subtypes and allows for the identification of genetic markers that may be associated with tumor progression. The observed tumor heterogeneity in the astrocytoma and glioma cases corroborates previous FISH studies and suggests a multiclonal mechanism of tumor progression in low and high grade gliomas rather than gradual clonal evolution. This, together with chromothripsis, could reflect an aggressive character of astrocytomas and gliomas.

Abstract 3: Molecular markers of prostate cancer: Investigation of microRNA profiles as a marker in patients with high-risk prostate cancer.

Abstract Purpose: The aim of this study was to investigate the microRNA (miRNA) profile in prostate carcinoma as biomarkers to identify high-risk prostate cancer patients who may benefit from post-prostatectomy radiation therapy using global miRNA profiling. Method: Tumor from Formalin-Fixed Paraffin-Embedded (FFPE) tissues were obtained from 9 radical prostatectomy specimens resected for high-risk prostate cancer, to perform a pilot study using the Nanostring miRNA platform from isolated RNA. An optimized protocol utilizing the Ambion RecoverAll digestion buffer and the Qiagen miRNeasy FFPE kit was used to isolate total RNA. Each prostatectomy specimen was marked by a genitourinary pathologist and 1 mm cores of enriched areas of tumor or normal epithelial or stromal tissue were obtained. To analyze global miRNA expression, the Nanostring nCounter human miRNA Expression Assay Kit was used. The data was further analyzed in collaboration with The Ohio State University Center for Biostatistics. Results: The expression of miRNA in prostate tumor samples was compared to normal epithelium. It showed that seven miRNAs (miR-375, miR-18a, miR-25, miR-183, miR-641, miR-15b, miR-548a-3p) that were >1.5-fold upregulated and 4 miRNAs (miR-660, miR-1915, miR-200b, miR-205) <1.5-fold downregulated. Three (miR-375, miR-183, miR-205) were in accordance with previous studies published on prostate cancer. Expression of six up-regulated miRNAs (miR-205, miR-877, miR-K12-4-5p, miR-548b-3p, miR-34c-5p, ebv-miR-BART10) correlated with high risk (T>3 and/or Gleason score ≥ 8) and five miRNAs (up-regulated: miR-10b, miR-205; down-regulated: miR-574-5p, miR-30c, miR-499-5p) with pathological tumor stage 2 and 3. Conclusion: Our results suggest great potential for the use of miRNA profiling as a novel diagnostic and prognostic biomarker in defining the signatures of prostate cancer at different stages. We are currently completing the RNA isolation and downstream analyses in correlation with clinical data for 80 additional high-risk prostate cancer cases from the University hospital of Freiburg, Germany. Citation Format: Petra Stegmaier, Simon Kirste, Xiaokui M. Mo, Debra L. Zynger, Arnab Chakravarti, Erica Hlavin Bell. Molecular markers of prostate cancer: Investigation of microRNA profiles as a marker in patients with high-risk prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3. doi:10.1158/1538-7445.AM2013-3

Multivariate methods and artificial neural networks in the assessment of the response of infaunal assemblages to sediment metal contamination and organic enrichment

A 4-year annual sediment survey was conducted in an organically enriched tidal channel to compare the performance of univariate community descriptors, traditional multivariate techniques (TM) and artificial neural networks (AANs), in the assessment of infaunal responses to moderate levels of sediment metal contamination. Both TM approaches and the SOM ANN revealed spatiotemporal patterns of environmental and biological variables, suggesting a causal relationship between them and further highlighting subsets of taxa and sediment variables as potential main drivers of those patterns. Namely, high values of non-natural metals and organic content prompted high abundances of opportunists, while high values of natural metals yielded typical tolerant assemblages of organically enriched areas. The two approaches yielded identical final results but ANNs showed the following advantages over TM: ability to generalise results, powerful visualization tools and the ability to account simultaneously for sediment and faunal variables in the same analysis. Therefore, the SOM ANN, combined with the K-means clustering algorithm, is suggested as a promising tool for the assessment of the ecological quality of estuarine infaunal communities, although further work is needed to ensure the accuracy of the method.

Basic parameters and properties of the rapidly rotating magnetic helium-strong B star HR 7355*

The spectral and magnetic properties and variability of the B2Vnp emission-line magnetosphere star HR7355 were analyzed. The object rotates at almost 90% of the critical value, meaning it is a magnetic star for which oblateness and gravity darkening effects cannot be ignored any longer. A detailed modeling of the photospheric parameters indicate that the star is significantly cooler than suggested by the B2 spectral type, with T_eff=17500K atypically cool for a star with a helium enriched surface. The spectroscopic variability of helium and metal lines due to the photospheric abundance pattern is far more complex than a largely dipolar, oblique magnetic field of about 11 to 12kG may suggest. Doppler imaging shows that globally the most He enriched areas coincide with the magnetic poles and metal enriched areas with the magnetic equator. While most of the stellar surface is helium enriched with respect to the solar value, some isolated patches are depleted. The stellar wind in the circumstellar environment is governed by the magnetic field, i.e. the stellar magnetosphere is rigidly corotating with the star. The magnetosphere of HR7355 is similar to the well known \sigma Ori E: the gas trapped in the magnetospheric clouds is fairly dense, and at the limit to being optically thick in the hydrogen emission. Apart from a different magnetic obliquity, HR7355 and the more recently identified HR5907 have virtually identical stellar and magnetic parameters.

Microstructure and mechanical properties of directionally solidified and heat treated Nb–14Si–24Ti–2Cr alloy

In this work, the directional solidification of an Nb–14Si–24Ti–2Cr alloy (at-%) was performed at 1900°C with withdrawal rates of 1·2, 6 and 18 mm min−1, and the alloy was then heat treated (HT) at 1450°C for 100 h. The microstructures and mechanical properties of the directionally solidified and HT alloy were investigated. The phases present in the sample were confirmed to be NbSS dendrites, lath-like Nb3Si, eutectic NbSS+Nb3Si and Ti enriched areas. As the withdrawal rate increased, the effects of directional solidification became more evident, and the microstructure became more refined. After the heat treatment, the microstructure was characterised by NbSS dendrites, residual Nb3Si and lamellar eutectic NbSS+Nb3Si, which was decomposed from the lath-like Nb3Si. An increase in the withdrawal rate resulted in a decrease in the room temperature fracture toughness of the HT alloy. However, the room temperature compressive strength of the HT alloy increased to 1593·9 MPa with increasing withdrawal rate, which was twice the value of the compressive strength before heat treatment.

Experimental incorporation of Th into xenotime at middle to lower crustal P-T utilizing alkali-bearing fluids

In this study, a natural Th-absent xenotime [(Y+HREE)PO 4 ], is enriched in specific areas with respect to Th + Si utilizing a series of alkali-bearing fluids that included 2 N NaOH, 2 N KOH, Na 2 Si 2 O 5 + H 2 O, and NaF + H 2 O, in addition to ThO 2 and SiO 2 . Charge and fluid were sealed in Au capsules and placed in the piston-cylinder apparatus (CaF 2 assemblies) at 1000 MPa and 900 °C (8 to 25 days) or in cold-seal autoclaves on a hydrothermal line at 500 MPa and 600 °C (23 days). BSE imaging, EMP analysis, and TEM indicate that a fraction of the xenotime grains in the 2 N KOH, Na 2 Si 2 O 5 + H 2 O, and NaF + H 2 O experiments have altered areas enriched in Th + Si. No reaction was observed in the 2 N NaOH experiments. The altered areas occur as a series of curvilinear intergrowths with sharp compositional boundaries that extend from the edge of the xenotime grain into the interior. Formation of these Th + Si enriched areas is interpreted as a consequence of fluid-mediated coupled dissolution-reprecipitation.

Resolving brain regions using nanostructure initiator mass spectrometry imaging of phospholipids

In a variety of neurological diseases, pathological progression is cell type and region specific. Previous reports suggest that mass spectrometry imaging has the potential to differentiate between brain regions enriched in specific cell types. Here, we utilized a matrix-free surface mass spectrometry approach, nanostructure initiator mass spectrometry (NIMS), to show that spatial distributions of multiple lipids can be used as a 'fingerprint' to discriminate between neuronal- and glial- enriched brain regions. In addition, glial cells from different brain regions can be distinguished based on unique lipid profiles. NIMS images were generated from sagittal brain sections and were matched with immunostained serial sections to define glial cell enriched areas. Tandem mass spectrometry (LC-MS/MS QTOF) on whole brain extracts was used to identify 18 phospholipids. Multivariate statistical analysis (Nonnegative Matrix Factorization) enhanced differentiation of brain regions and cell populations compared to single ion imaging methods. This analysis resolved brain regions that are difficult to distinguish using conventional stains but are known to have distinct physiological functions. This method accurately distinguished the frontal (or somatomotor) and dorsal (or retrosplenial) regions of the cortex from each other and from the pons region.

Deep sounding TEM investigation method based on a modified fixed central-loop system

Abstract The central-loop TEM technology has been widely used in mineral exploration, engineering and environmental investigations and assorted geologic studies. For easy and efficient working conditions, a square (or rectangular) loop is generally employed instead of a circular one. Any position within the inner one ninth of the central part of the loop is often designated as the central survey location (within which the field is assumed to be uniform), and referred to as a modified central-loop configuration. However, the deduced field parameters at such non-central positions when calculated by a central-loop formula result in decreased accuracy and possibly erroneous interpretation. A large-fixed loop offers the advantage of being able to determine the induced potential at any point inside or outside the loop. In this study we provide the formula for the large-fixed loop and receiver positions within the modified central-loop system and solve the problem. Specifically, we compute the electromagnetic response of any field point by using an electric dipole integration method. The full time-domain apparent resistivity values are then extracted by using an iterative method. Both theoretical modeling and real data examples indicate that such a configuration not only improves the accuracy for the TEM survey, but also enlarges the exploration depth, due to a large loop used in the deployment. The method is used for locating the water enriched areas in coal mines in Yangquan region of Shanxi province and in Bin County of Shaanxi province, China. The interpreted results are tested by later drilling, which confirmed our combined method to be a reliable and efficient method for deep sounding.

Cortactin deficiency is associated with reduced neutrophil recruitment but increased vascular permeability in vivo

Neutrophil extravasation and the regulation of vascular permeability require dynamic actin rearrangements in the endothelium. In this study, we analyzed in vivo whether these processes require the function of the actin nucleation-promoting factor cortactin. Basal vascular permeability for high molecular weight substances was enhanced in cortactin-deficient mice. Despite this leakiness, neutrophil extravasation in the tumor necrosis factor-stimulated cremaster was inhibited by the loss of cortactin. The permeability defect was caused by reduced levels of activated Rap1 (Ras-related protein 1) in endothelial cells and could be rescued by activating Rap1 via the guanosine triphosphatase (GTPase) exchange factor EPAC (exchange protein directly activated by cAMP). The defect in neutrophil extravasation was caused by enhanced rolling velocity and reduced adhesion in postcapillary venules. Impaired rolling interactions were linked to contributions of β(2)-integrin ligands, and firm adhesion was compromised by reduced ICAM-1 (intercellular adhesion molecule 1) clustering around neutrophils. A signaling process known to be critical for the formation of ICAM-1-enriched contact areas and for transendothelial migration, the ICAM-1-mediated activation of the GTPase RhoG was blocked in cortactin-deficient endothelial cells. Our results represent the first physiological evidence that cortactin is crucial for orchestrating the molecular events leading to proper endothelial barrier function and leukocyte recruitment in vivo.

Biosorption Capacity for Cadmium of Brown Seaweed Sargassum sinicola and Sargassum lapazeanum in the Gulf of California

Brown algae Sargassum sinicola and Sargassum lapazeanum were tested as cadmium biosorbents in coastal environments close to natural and enriched areas of phosphorite ore. Differences in the concentration of cadmium in these brown algae were found, reflecting the bioavailability of the metal ion in seawater at several sites. In the laboratory, maximum biosorption capacity (q max) of cadmium by these nonliving algae was determined according to the Langmuir adsorption isotherm as 62.42 ± 0.44 mg g−1 with the affinity constant (b) of 0.09 and 71.20 ± 0.80 with b of 0.03 for S. sinicola and S. lapazeanum, respectively. Alginate yield was 19.16 ± 1.52% and 12.7 ± 1.31%, respectively. Although S. sinicola had far lower biosorption capacity than S. lapazeanum, the affinity for cadmium for S. sinicola makes this alga more suitable as a biosorbent because of its high q max and large biomass on the eastern coast of the Baja California Peninsula. Sargassum biomass was estimated at 180,000 t, with S. sinicola contributing to over 70%.

TEM study of Mg distribution in micrite crystals from the Mishrif reservoir Formation (Middle East, Cenomanian to Early Turonian)

Microporous limestones composed of micrite crystals constitute sizeable hydrocarbon reservoirs throughout the world and especially in the Middle East. However, the crystallization history of micrites is poorly understood. Scanning electronic microscopy (SEM) with X-ray energy dispersive spectroscopy (EDS) studies give morphological and bulk composition information about micrites, but no information exists on the distribution of minor elements inside micrite grains. This study proposes Mg maps obtained with X-ray EDS combined with scanning transmission electron microscopy (STEM) of micrite crystals from the Mishrif reservoir Formation (Middle East, Cenomanian to Early Turonian). Three types of Mg distribution were observed through micrite crystals from five different samples: (1) homogenous Mg concentration, (2) small Mg-enriched areas close to the center of the crystal, and (3) geometric Mg impoverishments near crystal edges and parallel to present crystallographic faces. The homogenous Mg distribution is the most frequent and is found both in microporous and in tight micrites. The second type of distribution showing small Mg-enriched areas inside micrite crystals relatively close to their center comes from a microporous sample located below an emersive surface. These enriched areas may correspond to crystal seeds. The third type of distribution was observed in micrite crystals from another microporous sample situated just below an emersive surface. The Mg-poor zones probably represent overgrowths that precipitated in contact with less Mg-rich meteoric fluids.