Influence of the crosstalk on the intensity of HAADF-STEM images of quaternary semiconductor materials.

The influence of the neighbouring atomic-columns in determining the composition at atomic column scale of quaternary semiconductor compounds, using simulated HAADF-STEM images is evaluated. The InAlAsSb alloy, a promising material in the photovoltaic field, is considered. We find that the so called 'crosstalk' effect plays an important role for the aimed compositional determination. The intensity transfer is larger from neighbouring atomic columns with higher average Z, and towards atomic columns with smaller Z. Our results show that in order to obtain precise information on the column composition, the HAADF-STEM intensities of both columns need to be taken into account simultaneously.

Bacterial community structure and response to nitrogen amendments in Lake Shenandoah (VA, USA).

Microbial processes are critical to the function of freshwater ecosystems, yet we still do not fully understand the factors that shape freshwater microbial communities. Furthermore, freshwater ecosystems are particularly susceptible to effects of environmental change, including influx of exogenous nutrients such as nitrogen and phosphorus. To evaluate the impact of nitrogen loading on the microbial community structure of shallow freshwater lakes, water samples collected from Lake Shenandoah (Virginia, USA) were incubated with two concentrations of either ammonium, nitrate, or urea as a nitrogen source. The potential impact of these nitrogen compounds on the bacterial community structure was assessed via 16S rRNA amplicon sequencing. At the phylum level, the dominant taxa in Lake Shenandoah were comprised of Actinobacteria and Proteobacteria, which were not affected by exposure to the various nitrogen treatments. Overall, there was not a significant shift in the diversity of the bacterial community of Lake Shenandoah with the addition of nitrogen sources, indicating this shallow system may be constrained by other environmental factors.

Relationship between mozzarella yield and milk composition, processing factors, and recovery of whey constituents.

Our aim was to identify the relationship between mozzarella cheese yield and buffalo milk composition, processing factors, and recovery of whey constituents. A production of 30 batches of mozzarella cheese at a dairy industry in northeast Brazil (Rio Grande do Norte) was monitored between March and November 2015. Mozzarella yield and 32 other variables were observed for each batch, and divided into 3 groups: milk composition variables (12); variables involved in the cheesemaking process (14); and variables for recovery of whey constituents (6). Data were analyzed using descriptive statistics, Pearson correlation, and principal component analysis. Most of the correlations between milk composition variables and between the variables of the manufacturing processes were not significant. Significant correlations were mostly observed between variables for recovery of whey constituents. Yield only showed significant correlation with time elapsed between curd cuttings and age of the starter culture, and it showed greater association with age of the starter culture, time elapsed between curd cuttings, and during stretching, as well as with milk pH and density. Thus, processing factors and milk characteristics are closely related to dairy efficiency in mozzarella manufacturing.

Antimicrobial activity and chemical composition of fixed oil extracted from the body fat of the snake Spilotes pullatus.

CONTEXT: Ethnozoological studies have shown that Spilotes pullatus Linn. (Colubridae: Ophidia), is associated with medicinal and magic-religious uses in Brazil. OBJECTIVES: This study was designed to determine the chemical composition of the oil extracted from the body fat of S. pullatus and to test its antimicrobial properties, alone and in association with aminoglycosides, against fungi and bacterial strains in concentrations ranging between 1024 and 0.5 µg/mL. MATERIAL AND METHODS: The snakes were collected in the Chapada do Araripe, county of Crato, Ceará State, Brazil. The oil was extracted in a Soxhlet apparatus using hexane. The methyl esters of the fatty acids present in the samples were identified using GC-MS. The antimicrobial and drug modulatory activities of oil were tested by microdilution against fungal and bacterial strains. RESULTS: The chemical composition of the fixed oils of S. pullatus identified 10 constituents representing 94.97% of the total sample. The percentages of saturated and unsaturated fatty acids were 33.59 and 61.38%, respectively, with the most abundant components being elaidic (37.26%). The oil did not demonstrate any antimicrobial or antifungal activity when tested alone, presenting MIC values ≥ 1024 µg/mL. However, when associated with antibiotics, it demonstrated synergistic effects with gentamicin against all the bacterial lineages assayed, and antagonistic effects with amikacin and neomycin against strains of Escherichia coli. CONCLUSIONS: Oil extracted from the body fat of S. pullatus did not demonstrate any inhibitory effects on bacterial or fungal activities, but was effective in modulating the effects of certain antibiotics.

Investigation of the cytocidal potential of Rhinella jimi skin methanol extracts.

CONTEXT: Amphibian skins have wide variety of biologically active compounds associated with the natural defenses of these animals. OBJECTIVES: To study the in vitro anticancer activity of methanol extracts of the skin of Rhinella jimi Stevaux (Anura: Bufonidae). MATERIAL AND METHODS: The extract was obtained by cold methanol extraction for 96 h using dried skins (295 mg). The methanol skin extract was dried under reduced pressure, giving a 5.5% yield. In order to test for growth-inhibitory activity, in vitro tests were performed with the following cancer cell lines using concentrations ranging between 0.25-250 µg/mL of the extract by 48 h: K562 (leukemia), MCF-7 (breast), NCI-ADR (breast with MDR phenotype), UACC-62 (melanoma), NCI460 (lung), PCO3 (prostate), HT-29 (colon), OVCAR (ovary), and 786-0 (kidney). RESULTS: The methanol extract of R. jimi produced a growth inhibition in a dose-dependent manner against the most of the assayed cell lines. In addition to the growth inhibition, the extract induced the cell death in the ovary and colon lines (EC50 0.125 and 0.2 µg/mL, respectively), demonstrating 100% of inhibition with 2.5 µg/mL. However, prostate and leukemia cell lines demonstrated less sensitivity, with EC50 of 24 and 235 µg/mL, respectively. This is the first report about the anticancer activity by natural products from the skin of R. jimi. CONCLUSIONS: The methanol extracts of R. jimi significantly affected the growth of several cell lines, demonstrating that these compounds are a potential source of substances that could be utilized in cancer treatments.

Morphological evolution of InAs/InP quantum wires through aberration-corrected scanning transmission electron microscopy.

Evolution of the size, shape and composition of self-assembled InAs/InP quantum wires through the Stranski-Krastanov transition has been determined by aberration-corrected Z-contrast imaging. High resolution compositional maps of the wires in the initial, intermediate and final formation stages are presented. (001) is the main facet at their very initial stage of formation, which is gradually reduced in favour of [114] or [118], ending with the formation of mature quantum wires with {114} facets. Significant changes in wire dimensions are measured when varying slightly the amount of InAs deposited. These results are used as input parameters to build three-dimensional models that allow calculation of the strain energy during the quantum wire formation process. The observed morphological evolution is explained in terms of the calculated elastic energy changes at the growth front. Regions of the wetting layer close to the nanostructure perimeters have higher strain energy, causing migration of As atoms towards the quantum wire terraces, where the structure is partially relaxed; the thickness of the wetting layer is reduced in these zones and the island height increases until the (001) facet is removed.

Column-by-column compositional mapping by Z-contrast imaging.

A phenomenological method is developed to determine the composition of materials, with atomic column resolution, by analysis of integrated intensities of aberration-corrected Z-contrast scanning transmission electron microscopy images. The method is exemplified for InAs(x)P(1-x) alloys using epitaxial thin films with calibrated compositions as standards. Using this approach we have determined the composition of the two-dimensional wetting layer formed between self-assembled InAs quantum wires on InP(001) substrates.

Analysis of methanogenic activity in a thermophilic-dry anaerobic reactor: use of fluorescent in situ hybridization.

Methanogenic activity in a thermophilic-dry anaerobic reactor was determined by comparing the amount of methane generated for each of the organic loading rates with the size of the total and specific methanogenic population, as determined by fluorescent in situ hybridization. A high correlation was evident between the total methanogenic activity and retention time [-0.6988Ln(x)+2.667] (R(2) 0.8866). The total methanogenic activity increased from 0.04x10(-8) mLCH(4) cell(-1)day(-1) to 0.38x10(-8) mLCH(4) cell(-1)day(-1) while the retention time decreased, augmenting the organic loading rates. The specific methanogenic activities of H(2)-utilizing methanogens and acetate-utilizing methanogens increased until they stabilised at 0.64x10(-8) mLCH(4) cell(-1)day(-1) and 0.33x10(-8) mLCH(4) cell(-1)day(-1), respectively. The methanogenic activity of H(2)-utilizing methanogens was higher than acetate-utilizing methanogens, indicating that maintaining a low partial pressure of hydrogen does not inhibit the acetoclastic methanogenesis or the anaerobic process.

Evolution of microorganisms in thermophilic-dry anaerobic digestion.

Microbial population dynamics were studied during the start-up and stabilization periods in thermophilic-dry anaerobic digestion at lab-scale. The experimental protocol was defined to quantify Eubacteria and Archaea using Fluorescent in situ hybridization (FISH) in a continuously stirred tank reactor (CSTR), without recycling solids. The reactor was subjected to a programme of steady-state operation over a range of the retention times from 40 to 25 days, with an organic loading rate between 4.42 and 7.50 kg volatile solid/m3/day. Changes in microbial concentrations were linked to traditional performance parameters such as biogas production and VS removal. The relations of Eubacteria:Archaea and H2-utilising methanogens:acetate-utilising methanogens were 88:12 and 11:1, respectively, during start-up stage. Hydrogenotrophic methanogens, although important in the initial phase of the reactor start-up, were displaced by acetoclastic methanogens at steady-state, thus their relation were 7:32, respectively. The methane yield coefficient, the methane content in the biogas and VS removal were stabilized around 0.30 LCH4/gCOD, 50% and 80%, respectively. Methanogenic population correlated well with performance measurements.

Field validation of a battery of biomarkers to assess sediment quality in Spanish ports.

Two marine invertebrates, the crab Carcinus maenas and the clam Ruditapes philippinarum, were used as bioindicator species to assess contamination when exposed in situ to sediment from different sites from four Spanish ports Cadiz (SW Spain), Huelva (SW Spain), Bilbao (NE Spain) and Pasajes (NE Spain). In an attempt to determine sediments toxicity, a combination of exposure biomarkers was analyzed in both species: metallothionein-like-proteins (MTLPs), ethoxyresorufin O-deethylase (EROD), glutathione S-transferase activity (GST), glutathione peroxidase (GPX) and glutathione reductase (GR). In parallel, physical and chemical characterization of the different sediments was performed and biological responses related to the contaminants. Significant induction of MTLPs was observed when organisms were exposed to metal contaminated sediments (port of Huelva), and EROD and GPX activities after exposure to sediments containing organic compounds (port of Bilbao and Pasajes). No significant interspecies differences were observed in biomarker responses except for the GST and GR.

Accumulation and histopathological damage in the clam Ruditapes philippinarum and the crab Carcinus maenas to assess sediment toxicity in Spanish ports.

The degree of contamination and toxicity in sediment from four Spanish ports (Cádiz, Huelva, Pasajes and Bilbao) was assessed in the present study. Two marine invertebrate species, the shore crab Carcinus maenas and the clam Ruditapes philippinarum, were exposed to the different sediments under laboratory conditions for 28 days. Relationships were developed among metal contamination (As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn) in sediments, metal accumulation in gill tissues and histopathological lesions in different biological tissues to assess sediment toxicity. A multivariate analysis approach was used to calculate sediment quality guidelines (SQGs) by linking metal concentration in sediments with histopathological lesions measured in the exposed organisms. The results showed significant contaminant accumulation and histopathological lesions due to As, Pb and Zn in sediments at the port of Huelva; As, Cr, Cu, Hg and Ni at the ports of Pasajes and Cádiz; and Cr and Hg at the port of Bilbao. The link between chemical concentration in sediments and histopathological lesions allowed the determination of SQGs for the chemicals As, Cd, Cu, Cr, Hg, Ni and Zn.

Analysis of Bi Distribution in Epitaxial GaAsBi by Aberration-Corrected HAADF-STEM.

The Bi content in GaAs/GaAs1 - xBi x /GaAs heterostructures grown by molecular beam epitaxy at a substrate temperature close to 340 °C is investigated by aberration-corrected high-angle annular dark-field techniques. The analysis at low magnification of high-angle annular dark-field scanning transmission electron microscopy images, corroborated by EDX analysis, revealed planar defect-free layers and a non-homogeneous Bi distribution at the interfaces and within the GaAsBi layer. At high magnification, the qHAADF analysis confirmed the inhomogeneous distribution and Bi segregation at the GaAsBi/GaAs interface at low Bi flux and distorted dumbbell shape in areas with higher Bi content. At higher Bi flux, the size of the Bi gathering increases leading to roughly equiaxial Bi-rich particles faceted along zinc blende {111} and uniformly dispersed around the matrix and interfaces. FFT analysis checks the coexistence of two phases in some clusters: a rhombohedral pure Bi (rh-Bi) one surrounded by a zinc blende GaAs1 - xBi x matrix. Clusters may be affecting to the local lattice relaxation and leading to a partially relaxed GaAsBi/GaAs system, in good agreement with XRD analysis.

Dry-thermophilic anaerobic digestion of organic fraction of the municipal solid waste: focusing on the inoculum sources.

The effect of inoculum source on anaerobic thermophilic digestion of separately collected organic fraction of municipal solid wastes (SC_OFMSW) has been studied. Performance of laboratory scale reactors (V: 1.1 L) were evaluated using six different inoculums sources: (1) corn silage (CS); (2) restaurant waste digested mixed with rice hulls (RH_OFMSW); (3) cattle excrement (CATTLE); (4) swine excrement (SWINE); (5) digested sludge (SLUDGE); and (6) SWINE mixed with SLUDGE (1:1) (SWINE/SLUDGE). The SC_OFMSW was separately and collected from university restaurant. The selected conditions were: 25% of inoculum, 30% of total solid and 55 degrees C of temperature, optimum in the thermophilic range. The six inoculum sources showed an initial start-up phase in the range between 2 and 4 days and the initial methane generation began over 10 days operational process. Results indicated that SLUDGE is the best inoculum source for anaerobic thermophilic digestion of the treatment of organic fraction of municipal solid waste at dry conditions (30%TS). Over 60 days operating period, it was confirmed that SLUDGE reactor can achieve 44.0%COD removal efficiency and 43.0%VS removal. In stabilization phase, SLUDGE reactor showed higher volumetric biogas generated of 78.9 mL/day (or 35.6 mLCH(4)/day) reaching a methane yield of 0.53 LCH(4)/gVS. Also, SWINE/SLUDGE and SWINE were good inoculums at these experimental conditions.

Performance of anaerobic thermophilic fluidized bed in the treatment of cutting-oil wastewater.

This paper examines the effect of organic loading rate on the removal efficiency of COD and TOC anaerobic thermophilic fluidized bed reactor (AFBR) in the treatment of cutting-oil wastewater at different hydraulic retention time (HRT) conditions. The essays are development at laboratory scale using a porous support medium. The AFBR reactor was subjected to a programme of steady-state operation over a range of hydraulic retention times, HRTs, in the range 12-2h and organic loading rates, OLRs, between 11.9 and 51.3kgCOD/m(3)d. The highest efficiency was 95.9% for an OLR of 13kgCOD/m(3)d and HRT of 11h. Over an operating period of 92 days, an OLR of 51.3kgCOD/m(3)d was achieved with 67.1% COD removal efficiency (71.3% TOC) in the experimental AFBR reactor. Although the level of biogas generation was not high, the anaerobic fluidized bed technology provided significant advantages over the conventional physico-chemical treatment applied in the factory. The effluent had a better quality (lower organic loading) and it was possible to reuse it in different applications in the factory (e.g., irrigation of gardens). The biological treatment did not lead to the generation of oily sludge, which is considered as hazardous waste by legislation. Furthermore, a continuous stream is produced and this reduced the impact of large flows discharged 4-5 times per week to the urban collector and MWWTP (municipal wastewater treatment plant).

Bacterial killing in gastric juice--effect of pH and pepsin on Escherichia coli and Helicobacter pylori.

The susceptibility of Escherichia coli and Helicobacter pylori to pH and the effect of pepsin-mediated proteolysis were investigated. This was to establish the relative importance of their bacterial killing properties in gastric juice. Solutions in the pH range 1.5-7.4 with or without pig pepsin A were used, together with seven gastric juice samples obtained from patients undergoing routine gastric collection. Escherichia coli C690 (a capsulate strain), E. coli K-12 (a rough mutant) and Helicobacter pylori E5 were selected as the test organisms. Suspensions of bacteria (1x10(6) E. coli ml-1 and 1x10(8) H. pylori ml-1) were pre-incubated with test solutions at 37 degrees C for up to 2 h, and then cultured to establish the effect on subsequent growth. Survival of bacteria was diminished at pHs of less than 3.5, whereas killing required a pH of less than 2.5. Pre-incubation with pig pepsin at 0.5, 1.0 and 2.0 mg ml-1 at pH 3.5 reduced viable counts by 100% for E. coli 690 and E. coli K-12 after 100 min incubation. With H. pylori, the viable counts decreased to 50% of the control after 20 min incubation in 1 mg pepsin ml-1 at pH 2.5, 3.0 and 3.5. The gastric juices showed bactericidal activity at pH 3.5, and the rate of killing was juice dependent, with complete death of E. coli 690 occurring between 5 and 40 min post-incubation. Thus, killing of E. coli and H. pylori occurs optimally at pHs of less than 2.5. At pH 3.5, little effect is observed, whereas addition of pepsin alone or in gastric juice causes a marked increase in bacterial susceptibility, suggesting an important role for proteolysis in the killing of bacteria.

The prognosis of inflammatory bowel disease.

The complications of ulcerative colitis generally develop during the first two years of disease. The mortality is higher than expected and the highest likelihood of colectomy also occurs early in the disease. Mortality in Crohn's disease is greater than expected, especially in males. For both conditions, the overall mortality has decreased steadily, and currently is less than 5%. Ulcerative colitis is curable with proctocolectomy and ileostomy. In Crohn's disease, intestinal resection and reanastomosis is followed by recurrence in the majority of patients. The recurrence rate after proctocolectomy and ileostomy for Crohn's disease of the colon also is considerable, ranging from 20% to 35%. In ulcerative colitis, the more colon involved, the more frequent and more serious are the complications. In Crohn's disease, the anatomic pattern of disease tends to predict the type and extent of complications. Both ulcerative colitis and Crohn's disease appear to follow a more severe course in children and adolescents with "inflammatory bowel disease." Patients with either ulcerative colitis or Crohn's disease are at increased risk for the later development of cancer. In ulcerative colitis, the excess risk is limited to colorectal cancer. Patients with Crohn's disease have increased cancer rates for both the small and large bowel. Finally, most patients with these diseases are able to maintain normal occupations and enjoy reasonably stable social and economic situations. The successful adaptation of patients with inflammatory bowel disease is influenced by a hopeful, optimistic personality and by an encouraging, supportive physician.

Thermophilic anaerobic degradation of distillery wastewater in continuous-flow fluidized bed bioreactors.

This paper reports and discusses a laboratory experiment that tested the anaerobic fluidized bed (AFB) technology as a means for the treatment of concentrated industrial wastewater (wine distillery, vinasses) at thermophilic conditions. The purposes were to operate and characterize AFB under high organic loading conditions and to report on their steady-state performance. Experimentally, it was confirmed that AFB systems can achieve > 82.5% chemical oxygen demand (COD) reduction at a COD loading of 32.3 kg of COD m-3 day-1 for treating vinasses of wine. At hydraulic retention time (HRT) of 0.46 day, the volumetric rate of methane generation was 5.8 m3 of CH4 m-3 day-1 with a methane yield of 0.33 m3 of CH4/kg of COD removal. The greatest efficiency of substrate removal was 97% for an organic loading rate of 5.9 kg of COD m-3 day-1 and HRT of 2.5 days. The food-to-microorganism (F:M) ratio can be used as a parameter for treatment performance evaluation of AFB. For vinasses, excellent COD reduction and methane production were achievable at the F:M ratio of 0.55 kg of COD kg-1 VSatt day-1 (more than 80% of feed COD was removed, and 9 m3 m-3 day-1 of methane was produced).

Environmental impact of unleaded gasolines in the bay of Cádiz (Spain).

Given the strategic situation of the José León de Carranza bridge, which spans the Bay of Cádiz (in the SW of Spain) and carries very heavy motor traffic, together with knowledge of the currents and tidal flows in the zone, we have used a technique of radioactive dating of sediments to study the temporal evolution presented by contamination from lead in the sediment column. This has allowed us to observe the environmental impact, in terms of the concentration of Pb in the sea bed sediments, that has been produced in the zone by the introduction of unleaded gasolines as substitutes for traditional automobile fuels that employ organic forms of tetra methyl lead as an antidetonant agent in the fuel.

Pre-treatment optimisation studies for secondary effluent reclamation with reverse osmosis.

Physical-chemical pre-treatment was used for the reverse osmosis unit for reclamation of secondary effluents. The pilot plant was equipped with a variety of tertiary treatment units to prevent fouling and biofouling of the cellulose-acetate reverse osmosis membranes used. The optimisation of pre-treatment involved application of various concentrations of lime to raise the pH to 10.3-12.1, and to stabilise the sludge generated, as well as different dosages of ferric chloride (15, 20, and 25 mg/L) for the coagulation and solid-liquid separation. Sodium hypochlorite (8 mg/L) and UV disinfection are used for microbiological control. The water quality obtained, under the optimum conditions (pH=10.5; FeCl(3): 25 mg/L; anionic flocculant: 0.5 mg/L; sodium hypochlorite: 8 mg/L) was high, showing an average conductivity of 66 microS/cm and low COD values 4 mg O(2)/L. The product water is suitable for injection into a groundwater aquifer to counteract seawater intrusion.

Dating of marine sediments and time evolution of heavy metal concentrations in the Bay of Cádiz, Spain.

In this paper the time evolution of heavy metal concentration of Pb, Zn, Cd and Hg, in the sediments of the Bay of Cádiz (southwest of Spain) is studied during the past century, as a result of the industrial influence in the zone. The study has been performed using sedimentary profiles that have been extracted from the seabed. The measurement of 210Pb and 137Cs radionuclides has provided the dating of the sediment layers, up to a depth corresponding to the age of 115 years. The relative sedimentation rates obtained are around 0.2 cm/year. The 137Cs activity profile reflects the concentration of this radionuclide in the atmosphere and into aquatic systems during the second half of the twentieth century. This profile has been used to ratify the results provided by the 210Pb dating method.