Structural, optical, magnetic and photocatalytic properties of Co doped CuS diluted magnetic semiconductor nanoparticles

International Nuclear Information System (INIS)

Sreelekha, N.; Subramanyam, K.; Amaranatha Reddy, D.; Murali, G.; Ramu, S.; Rahul Varma, K.; Vijayalakshmi, R.P.

2016-01-01

Highlights: • Cu_1_−_xCo_xS nanoparticles were synthesized via chemical co-precipitation method. • Structural, band gap, magnetization and photocatalysis studies were carried out. • All the doped samples exhibited intrinsic room temperature ferromagnetism. • Effect of magnetic properties on photocatalytic activity was analyzed. • CuS:Co nanoparticles may find applications in photocatalytic and spintronic devices. - Abstract: Pristine and Co doped covellite CuS nanoparticles were synthesized in aqueous solution by facile chemical co-precipitation method with Ethylene Diamine Tetra Acetic Acid (EDTA) as a stabilizing agent. EDAX measurements confirmed the presence of Co in the CuS host lattice. Hexagonal crystal structure of pure and Co doped CuS nanoparticles were authenticated by XRD patterns. TEM images indicated that sphere-shape of nanoparticles through a size ranging from 5 to 8 nm. The optical absorption edge moved to higher energies with increase in Co concentration as indicated by UV–vis spectroscopy. Magnetic measurements revealed that bare CuS sample show sign of diamagnetic character where as in Co doped nanoparticles augmentation of room temperature ferromagnetism was observed with increasing doping precursor concentrations. Photocatalytic performance of the pure and Co doped CuS nanoparticles were assessed by evaluating the degradation rate of rhodamine B solution under sun light irradiation. The 5% Co doped CuS nanoparticles provide evidence for high-quality photocatalytic activity.

Structural, optical, magnetic and photocatalytic properties of Co doped CuS diluted magnetic semiconductor nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Sreelekha, N.; Subramanyam, K. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Department of Physics, Raghu Engineering College, Visakhapatnam, Andrapradesh 531162 (India); Amaranatha Reddy, D. [Department of Chemistry and Chemical Institute for Functional Materials, Pusan National University, Busan 609735 (Korea, Republic of); Murali, G. [Department of BIN Fusion Technology & Department of Polymer-Nano Science and Technology, Chonbuk National University, Jeonju, Jeonbuk (Korea, Republic of); Ramu, S. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Rahul Varma, K. [Department of Mechanical Engineering, University of California, Berkeley (United States); Vijayalakshmi, R.P., E-mail: vijayaraguru@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India)

2016-08-15

Highlights: • Cu{sub 1−x}Co{sub x}S nanoparticles were synthesized via chemical co-precipitation method. • Structural, band gap, magnetization and photocatalysis studies were carried out. • All the doped samples exhibited intrinsic room temperature ferromagnetism. • Effect of magnetic properties on photocatalytic activity was analyzed. • CuS:Co nanoparticles may find applications in photocatalytic and spintronic devices. - Abstract: Pristine and Co doped covellite CuS nanoparticles were synthesized in aqueous solution by facile chemical co-precipitation method with Ethylene Diamine Tetra Acetic Acid (EDTA) as a stabilizing agent. EDAX measurements confirmed the presence of Co in the CuS host lattice. Hexagonal crystal structure of pure and Co doped CuS nanoparticles were authenticated by XRD patterns. TEM images indicated that sphere-shape of nanoparticles through a size ranging from 5 to 8 nm. The optical absorption edge moved to higher energies with increase in Co concentration as indicated by UV–vis spectroscopy. Magnetic measurements revealed that bare CuS sample show sign of diamagnetic character where as in Co doped nanoparticles augmentation of room temperature ferromagnetism was observed with increasing doping precursor concentrations. Photocatalytic performance of the pure and Co doped CuS nanoparticles were assessed by evaluating the degradation rate of rhodamine B solution under sun light irradiation. The 5% Co doped CuS nanoparticles provide evidence for high-quality photocatalytic activity.

Isolation of a strain of Acidithiobacillus caldus and its role in bioleaching of chalcopyrite

Energy Technology Data Exchange (ETDEWEB)

Zhou, Q.G.; Bo, F.; Bo, Z.H.; Xi, L.; Jian, G.; Fei, L.F.; Hua, C.X. [Central South University of Technology, Changsha (China)

2007-09-15

A moderately thermophilic and acidophilic sulfur-oxidizing bacterium named S-2, was isolated from coal heap drainage. The bacterium was motile, Gramnegative, rod-shaped, measured 0.4 to 0.6 by 1 to 2 gm, and grew optimally at 42-45{sup o}C and an initial pH of 2.5. The strain S-2 grew autotrophically by using elemental sulfur, sodium thiosulfate and potassium tetrathionate as energy sources. The strain did not use organic matter and inorganic minerals including ferrous sulfate, pyrite and chalcopyrite as energy sources. The morphological, biochemical, physiological characterization and analysis based on 16S rRNA gene sequence indicated that the strain S2 is most closely related to Acidithiobacillus caldus (> 99% similarity in gene sequence). The combination of the strain S-2 with Leptospirillum ferriphilum or Acidithiobacillus ferrooxidans in chalcopyrite bioleaching improved the copper-leaching efficiency. Scanning electron microscope (SEM) analysis revealed that the chalcopyrite surface in a mixed culture of Leptospirillum ferriphilum and Acidithiobacillus caldus was heavily etched. The energy dispersive X-ray (EDX) analysis indicated that Acidithiobacillus caldus has the potential role to enhance the recovery of copper from chalcopyrite by oxidizing the sulfur formed during the bioleaching progress.

Production of recombinant proteins in Escherichia coli tagged with the fusion protein CusF3H.

Science.gov (United States)

Vargas-Cortez, Teresa; Morones-Ramirez, Jose Ruben; Balderas-Renteria, Isaias; Zarate, Xristo

2017-04-01

Recombinant protein expression in the bacterium Escherichia coli still is the number one choice for large-scale protein production. Nevertheless, many complications can arise using this microorganism, such as low yields, the formation of inclusion bodies, and the requirement for difficult purification steps. Most of these problems can be solved with the use of fusion proteins. Here, the use of the metal-binding protein CusF3H+ is described as a new fusion protein for recombinant protein expression and purification in E. coli. We have previously shown that CusF produces large amounts of soluble protein, with low levels of formation of inclusion bodies, and that proteins can be purified using IMAC resins charged with Cu(II) ions. CusF3H+ is an enhanced variant of CusF, formed by the addition of three histidine residues at the N-terminus. These residues then can bind Ni(II) ions allowing improved purity after affinity chromatography. Expression and purification of Green Fluorescent Protein tagged with CusF3H+ showed that the mutation did not alter the capacity of the fusion protein to increase protein expression, and purity improved considerably after affinity chromatography with immobilized nickel ions; high yields are obtained after tag-removal since CusF3H+ is a small protein of just 10 kDa. Furthermore, the results of experiments involving expression of tagged proteins having medium to large molecular weights indicate that the presence of the CusF3H+ tag improves protein solubility, as compared to a His-tag. We therefore endorse CusF3H+ as a useful alternative fusion protein/affinity tag for production of recombinant proteins in E. coli. Copyright © 2017 Elsevier Inc. All rights reserved.

Near-infrared radiation absorption properties of covellite (CuS using first-principles calculations

Directory of Open Access Journals (Sweden)

Lihua Xiao

2016-08-01

Full Text Available First-principles density functional theory was used to investigate the electronic structure, optical properties and the origin of the near-infrared (NIR absorption of covellite (CuS. The calculated lattice constant and optical properties are found to be in reasonable agreement with experimental and theoretical findings. The electronic structure reveals that the valence and conduction bands of covellite are determined by the Cu 3d and S 3p states. By analyzing its optical properties, we can fully understand the potential of covellite (CuS as a NIR absorbing material. Our results show that covellite (CuS exhibits NIR absorption due to its metal-like plasma oscillation in the NIR range.

Synthesis and optical properties of CuS nanoplate-based architectures by a solvothermal method

International Nuclear Information System (INIS)

Li Fei; Kong Tao; Bi Wentuan; Li Dachang; Li Zhen; Huang Xintang

2009-01-01

The controlled synthesis of copper sulfide (CuS) nanoplate-based architectures in different solvents has been realized at low cost by simply reaction of Cu(NO 3 ) 2 .3H 2 O and S under solvothermal conditions without the use of any template. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis spectrometer and fluorescence measurement were used to characterize the products. The products were all in hexagonal phase with high crystallinity and the morphology was significantly influenced by the solvents. The CuS products synthesized in dimethylformamide (DMF) were nanoplates and the samples prepared in ethanol were flower-like morphology composed of large numbers of nanoplates, but those synthesized in ethylene glycol (EG) were CuS architectures with high symmetry made up of several nanoplates arranged in a certain mode. The optical properties were investigated and the growth mechanisms of these CuS crystals were also proposed.

In situ preparation of CuS cathode with unique stability and high rate performance for lithium ion batteries

International Nuclear Information System (INIS)

Wang Yourong; Zhang Xianwang; Chen Peng; Liao Hantao; Cheng Siqing

2012-01-01

A simple approach, for the first time, was presented for in situ preparation of the CuS cathode. The obtained CuS cathodes were investigated by the measurements of X-ray diffraction pattern, scanning electronic microscopy, and electrochemical performance. The results indicate the CuS cathodes are composed of plenty of nano flakes, which construct a large 3-D net structure. Moreover, the CuS cathodes exhibit reversible capacity of 447.4, 414.1, 389.9 and 376.0 mAh g −1 at 0.2 C, 0.5 C, 1 C and 2 C respectively and excellent cycle stability for more than 100 cycles. The possible mechanism of the unique stability of the CuS cathode was discussed.

Gene Identification and Substrate Regulation Provide Insights into Sulfur Accumulation during Bioleaching with the Psychrotolerant Acidophile Acidithiobacillus ferrivorans

Science.gov (United States)

Liljeqvist, Maria; Rzhepishevska, Olena I.

2013-01-01

The psychrotolerant acidophile Acidithiobacillus ferrivorans has been identified from cold environments and has been shown to use ferrous iron and inorganic sulfur compounds as its energy sources. A bioinformatic evaluation presented in this study suggested that Acidithiobacillus ferrivorans utilized a ferrous iron oxidation pathway similar to that of the related species Acidithiobacillus ferrooxidans. However, the inorganic sulfur oxidation pathway was less clear, since the Acidithiobacillus ferrivorans genome contained genes from both Acidithiobacillus ferrooxidans and Acidithiobacillus caldus encoding enzymes whose assigned functions are redundant. Transcriptional analysis revealed that the petA1 and petB1 genes (implicated in ferrous iron oxidation) were downregulated upon growth on the inorganic sulfur compound tetrathionate but were on average 10.5-fold upregulated in the presence of ferrous iron. In contrast, expression of cyoB1 (involved in inorganic sulfur compound oxidation) was decreased 6.6-fold upon growth on ferrous iron alone. Competition assays between ferrous iron and tetrathionate with Acidithiobacillus ferrivorans SS3 precultured on chalcopyrite mineral showed a preference for ferrous iron oxidation over tetrathionate oxidation. Also, pure and mixed cultures of psychrotolerant acidophiles were utilized for the bioleaching of metal sulfide minerals in stirred tank reactors at 5 and 25°C in order to investigate the fate of ferrous iron and inorganic sulfur compounds. Solid sulfur accumulated in bioleaching cultures growing on a chalcopyrite concentrate. Sulfur accumulation halted mineral solubilization, but sulfur was oxidized after metal release had ceased. The data indicated that ferrous iron was preferentially oxidized during growth on chalcopyrite, a finding with important implications for biomining in cold environments. PMID:23183980

Lócus de controle em saúde e autoestima em portadores de diabetes mellitus tipo 2

Directory of Open Access Journals (Sweden)

Fernanda Silva Fuscaldi

2011-08-01

Full Text Available O presente estudo teve como objetivo relacionar os escores obtidos pela aplicação das escalas de lócus de controle da saúde e autoestima com variáveis sócio-demográficas, clínicas, fatores de risco e complicações crônicas em 65 portadores de diabetes mellitus do tipo 2. Trata-se de um estudo descritivo transversal onde foram utilizados, para a análise estatística, os testes de Qui-quadrado de Pearson, Mann-Whitney, Kruskal-Wallis e de Correlação de Spearman. Em relação ao lócus de controle, os pacientes apresentaram, em média, maiores escores na dimensão interna, sendo que as mulheres demonstraram maior externalidade-ao acaso para a saúde. Relações estatisticamente significativas foram encontradas entre internalidade com tempo de diagnóstico e atividade física; entre externalidade-outros poderosos com hemoglobina glicada e atividade física e entre externalidade-ao acaso com a prática de atividade física. A autoestima foi alta na maioria dos indivíduos, porém não se relacionou estatisticamente a nenhuma variável.

A genomic island provides Acidithiobacillus ferrooxidans ATCC 53993 additional copper resistance: a possible competitive advantage.

Science.gov (United States)

Orellana, Luis H; Jerez, Carlos A

2011-11-01

There is great interest in understanding how extremophilic biomining bacteria adapt to exceptionally high copper concentrations in their environment. Acidithiobacillus ferrooxidans ATCC 53993 genome possesses the same copper resistance determinants as strain ATCC 23270. However, the former strain contains in its genome a 160-kb genomic island (GI), which is absent in ATCC 23270. This GI contains, amongst other genes, several genes coding for an additional putative copper ATPase and a Cus system. A. ferrooxidans ATCC 53993 showed a much higher resistance to CuSO(4) (>100 mM) than that of strain ATCC 23270 (<25 mM). When a similar number of bacteria from each strain were mixed and allowed to grow in the absence of copper, their respective final numbers remained approximately equal. However, in the presence of copper, there was a clear overgrowth of strain ATCC 53993 compared to ATCC 23270. This behavior is most likely explained by the presence of the additional copper-resistance genes in the GI of strain ATCC 53993. As determined by qRT-PCR, it was demonstrated that these genes are upregulated when A. ferrooxidans ATCC 53993 is grown in the presence of copper and were shown to be functional when expressed in copper-sensitive Escherichia coli mutants. Thus, the reason for resistance to copper of two strains of the same acidophilic microorganism could be determined by slight differences in their genomes, which may not only lead to changes in their capacities to adapt to their environment, but may also help to select the more fit microorganisms for industrial biomining operations. © Springer-Verlag 2011

Mechanochemically synthesized sub-5 nm sized CuS quantum dots with high visible-light-driven photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Li, Shun; Ge, Zhen-Hua [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Bo-Ping, E-mail: bpzhang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Yao, Yao [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Huan-Chun [School of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Yang, Jing; Li, Yan; Gao, Chao [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Lin, Yuan-Hua [School of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China)

2016-10-30

Highlights: • CuS quantum dots (<5 nm) were synthesized by mechanochemical ball milling. • Defects was observed in the CuS quantum dots. • They show good visible light photocatalytic activity as Fenton-like reagents. - Abstract: We report a simple mechanochemical ball milling method for synthesizing monodisperse CuS quantum dots (QDs) with sizes as small as sub-5 nm. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis spectroscopy. The CuS QDs exhibited excellent visible-light-driven photocatalytic activity and stability for degradation of Rodanmine B aqueous solution as Fenton-like reagents. Our study opens the opportunity to low-cost and facile synthesis of QDs in large scale for future industrial applications.

Hierarchical, porous CuS microspheres integrated with carbon nanotubes for high-performance supercapacitors

Science.gov (United States)

Lu, Yang; Liu, Xianming; Wang, Weixiao; Cheng, Jinbing; Yan, Hailong; Tang, Chengchun; Kim, Jang-Kyo; Luo, Yongsong

2015-11-01

Carbon nanotubes (CNTs) incorporated porous 3-dimensional (3D) CuS microspheres have been successfully synthesized via a simple refluxing method assisted by PVP. The composites are composed of flower-shaped CuS secondary microspheres, which in turn are assembled with primary nanosheets of 15-30 nm in thickness and fully integrated with CNT. The composites possess a large specific surface area of 189.6 m2 g-1 and a high conductivity of 0.471 S cm-1. As electrode materials for supercapacitors, the nanocomposites show excellent cyclability and rate capability and deliver an average reversible capacitance as high as 1960 F g-1 at a current density of 10 mA cm-2 over 10000 cycles. The high electrochemical performance can be attributed to the synergistic effect of CNTs and the unique microstructure of CuS. The CNTs serve as not only a conductive agent to accelerate the transfer of electrons in the composites, but also as a buffer matrix to restrain the volume change and stabilize the electrode structure during the charge/discharge process. The porous structure of CuS also helps to stabilize the electrode structure and facilitates the transport for electrons.

Efficient photocatalytic performance enhancement in Co-doped ZnO nanowires coupled with CuS nanoparticles

Science.gov (United States)

Li, Wei; Wang, Guojing; Feng, Yimeng; Li, Zhengcao

2018-01-01

In this research, a kind of highly efficient semiconductor photocatalyst was fabricated by depositing CuS nanoparticles uniformly on the surface of Co-doped ZnO nanowires. ZnO nanowires were synthesized by hydrothermal method and CuS nanoparticles were modified by successive ionic layer adsorption and reaction (SILAR). By conducting methyl orange (MO) degradation experiments under the illumination of visible light, the photocatalytic activity of Co-doped ZnO nanowires modified with CuS nanoparticles was found to be nearly three times active when compared to bare ZnO nanowires. Its superior photocatalytic performance has two main reasons. The doped Co2+ ions can inhibit the recombination of photo-generated electron-hole pairs and decrease the optical bandgap, while the p-n heterostructure can enhance the visible light absorption ability and promote the separation of photo-excited charge carriers. Furthermore, the effect of the amount of deposited CuS nanoparticles on the photocatalysis was also investigated. The photocatalytic efficiency firstly raised along with the increment of SILAR cycle times and reached a maximum at 10 cycles but then decreased as the cycle times continue to increase. This originates from that an excessive amount of CuS would not only cover the active reacting sites, but also serve as recombination centers. Overall, this new nanostructure is expected to work as an efficient photocatalyst.

Bioleaching in batch tests for improving sludge dewaterability and metal removal using Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans after cold acclimation.

Science.gov (United States)

Zhou, Qingyang; Gao, Jingqing; Li, Yonghong; Zhu, Songfeng; He, Lulu; Nie, Wei; Zhang, Ruiqin

2017-09-01

Bioleaching is a promising technology for removal of metals from sludge and improvement of its dewaterability. Most of the previous studies of bioleaching were focused on removal of metals; bioleaching in cold environments has not been studied extensively. In this study, Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were acclimated at 15 °C and co-inoculated to explore the optimal conditions for improvement of sludge dewaterability and removal of metals by the sequencing batch reactors. The data show after 6 days of bioleaching at 15 °C, 89.6% of Zn, 72.8% of Cu and 39.4% of Pb were removed and the specific resistance to filtration (SRF) was reduced to ∼12%. In addition, the best conditions for bioleaching are an initial pH of 6, a 15% (v/v) inoculum concentration, and A. thiooxidans and A. ferrooxidans mixed in a ratio of 4:1. We found that bioleaching of heavy metals is closely related to final pH, while the sludge SRF is dominated by other factors. Bioleaching can be completed in 6 days, and the sludge dewaterability and removal of metals at 15 °C meet the requirements of most sewage treatment plants.

Effect of metal sulfide pulp density on gene expression of electron transporters in Acidithiobacillus sp. FJ2.

Science.gov (United States)

Fatemi, Faezeh; Miri, Saba; Jahani, Samaneh

2017-05-01

In Acidithiobacillus ferrooxidans, one of the most important bioleaching bacterial species, the proteins encoded by the rus operon are involved in the electron transfer from Fe 2+ to O 2 . To obtain further knowledge about the mechanism(s) involved in the adaptive responses of the bacteria to growth on the different uranium ore pulp densities, we analyzed the expression of the four genes from the rus operon by real-time PCR, when Acidithiobacillus sp. FJ2 was grown in the presence of different uranium concentrations. The uranium bioleaching results showed the inhibitory effects of the metal pulp densities on the oxidation activity of the bacteria which can affect Eh, pH, Fe oxidation and uranium extractions. Gene expression analysis indicated that Acidithiobacillus sp. FJ2 tries to survive in the stress with increasing in the expression levels of cyc2, cyc1, rus and coxB, but the metal toxicity has a negative effect on the gene expression in different pulp densities. These results indicated that Acidithiobacillus sp. FJ2 could leach the uranium even in high pulp density (50%) by modulation in rus operon gene responses.

Tailored synthesis of CuS nanodisks from a new macrocyclic precursor and their efficient catalytic properties on methylene blue dye degradation

International Nuclear Information System (INIS)

Islam, D. A.; Chakraborty, A.; Bhattacharya, B.; Sarkar, U.; Acharya, H.

2016-01-01

In this study, CuS nanodisks have been synthesized from a tetraaza (N_4) macrocyclic complex precursor by a facile wet chemical method. The crystallinity and morphology of the as-synthesized products were characterized by X-ray diffraction and transmission electron microscopy, which confirm a phase pure crystalline CuS nanostructures with ~15 to 20 nm in dimension with ~5 nm thickness. A possible formation mechanism and growth process of the CuS nanodisks are discussed using thiourea and tetraaza ligand as the sulfur donor and stabilizing agent, respectively. Cyclic N_4 ligand also acts as a binding agent to template-guide the oriented growth of CuS nanodisks. The optimized geometry of ligands and complexes was calculated using B3YLP functional, which indicates that the HOMO in the complex located on metal center and N atoms are weakly bonded to the metal center. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than under dark in the presence of H_2O_2. The C_t/C_0 plot as a function of time displays the higher MB degradation activity of CuS nanoparticles with H_2O_2. The recycle stability of CuS nanoparticles was even found to be >80 % after five cycles studied by repeating the MB degradation with same CuS nanoparticles sample.Graphical AbstractCuS nanostructures synthesized from a tetraaza macrocyclic complex precursor show the disk-like registry with average lateral dimension between 15 and 20 nm and thickness of 5 nm. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than in dark in the presence of H_2O_2.

Tailored synthesis of CuS nanodisks from a new macrocyclic precursor and their efficient catalytic properties on methylene blue dye degradation

Energy Technology Data Exchange (ETDEWEB)

Islam, D. A.; Chakraborty, A. [Assam University, Department of Chemistry, Centre for Soft Matters (India); Bhattacharya, B.; Sarkar, U. [Assam University, Department of Physics (India); Acharya, H., E-mail: himadriau@yahoo.co.in [Assam University, Department of Chemistry, Centre for Soft Matters (India)

2016-05-15

In this study, CuS nanodisks have been synthesized from a tetraaza (N{sub 4}) macrocyclic complex precursor by a facile wet chemical method. The crystallinity and morphology of the as-synthesized products were characterized by X-ray diffraction and transmission electron microscopy, which confirm a phase pure crystalline CuS nanostructures with ~15 to 20 nm in dimension with ~5 nm thickness. A possible formation mechanism and growth process of the CuS nanodisks are discussed using thiourea and tetraaza ligand as the sulfur donor and stabilizing agent, respectively. Cyclic N{sub 4} ligand also acts as a binding agent to template-guide the oriented growth of CuS nanodisks. The optimized geometry of ligands and complexes was calculated using B3YLP functional, which indicates that the HOMO in the complex located on metal center and N atoms are weakly bonded to the metal center. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than under dark in the presence of H{sub 2}O{sub 2}. The C{sub t}/C{sub 0} plot as a function of time displays the higher MB degradation activity of CuS nanoparticles with H{sub 2}O{sub 2}. The recycle stability of CuS nanoparticles was even found to be >80 % after five cycles studied by repeating the MB degradation with same CuS nanoparticles sample.Graphical AbstractCuS nanostructures synthesized from a tetraaza macrocyclic complex precursor show the disk-like registry with average lateral dimension between 15 and 20 nm and thickness of 5 nm. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than in dark in the presence of H{sub 2}O{sub 2}.

Atuação de Acidithiobacillus na solubilização de fosfato natural em solo de tabuleiro cultivado com jacatupé (Pachyrhizus erosus Effect of Acidithiobacillus on solubilization of natural phosphate in a coastal tableland soil under yam bean (Pachyrhizus erosus crop

Directory of Open Access Journals (Sweden)

N. P. Stamford

2004-02-01

Full Text Available Realizou-se um experimento em casa de vegetação para avaliar a atuação do enxofre (S inoculado com Acidithiobacillus na disponibilidade de fósforo (P de fosfato natural (FN, em diferentes modos de aplicação do fertilizante, em um Espodossolo Ferrocárbico Órtico, do tabuleiro costeiro da Zona da Mata de Pernambuco, cultivado com jacatupé (Pachyrhizus erosus. As plantas foram inoculadas com rizóbio (NFB 747 e NFB 748 e adicionado tratamento-controle sem inoculação com rizóbio. Os tratamentos com P foram: (1 FN revestindo o enxofre inoculado com Acidithiobacillus (FN S*, (2 FN revestido com S e com Acidithiobacillus (S* FN, (3 mistura FN com S e com Acidithiobacillus (FN + S*, (4 mistura FN com S e sem Acidithiobacillus (FN + S, (5 superfosfato triplo (ST e (6 sem aplicação de fósforo (P0. Os tratamentos foram aplicados: (a na superfície, (b em sulco 10 cm abaixo da semente, e (c em sulco 10 cm abaixo e ao lado da semente. A biomassa nodular foi maior no tratamento (FN + S* com melhor efeito quando aplicado ao lado e abaixo das sementes. O (FN + S* também aumentou a altura das plantas, a biomassa da parte aérea e das túberas e o N total da parte aérea, especialmente quando aplicado 10 cm abaixo das sementes. O P total da parte aérea foi mais elevado com (S* FN aplicado 10 cm abaixo das sementes. Os melhores teores de P no solo foram obtidos com (FN + S* e (S* FN, com efeito mais evidente quando aplicados 10 cm abaixo das sementes.A greenhouse experiment was carried out to evaluate the effect of sulphur (S inoculated with Acidithiobacillus on phosphorus (P availability from natural phosphate (NP using different fertilizer application methods on yam bean (Pachyrhizus erosus grown in a "Tableland Forest" soil (Podzol Hydromorphic dystrophic of the "Zona da Mata" in the State of Pernambuco, Brazil. Plants were inoculated with rhizobia strains (NFN 747 and NFB 748 and control treatments added without rhizobia inoculation. The P

Controllable architecture of CdS and CuS by single-source precursor-mediated approach and their photocatalytic activity

International Nuclear Information System (INIS)

Sahoo, Ashish K.; Srivastava, Suneel K.

2013-01-01

The present work deals with the preparation of hexagonal CdS and CuS by solvothermal decomposition of the morpholine-4-carbdithioate (MCDT) complexes of Cd and Cu in a water/THF mixture at 140–180 °C for 24 h and characterization. Scanning electron microscopy, field emission scanning electron microscopy and high resolution transmission electron microscopy show that CdS exhibits a hierarchical star- and lotus flower-like morphology in the presence of disodium salt of ethylenediamine tetraaceticacid and sodium dodecyl benzene sulphonate as soft templates at 140 and 160 °C, respectively. However, Cu complex of MCDT forms CuS nanoparticles in the temperature range of 140–180 °C. On the contrary, CdS nanoparticles and CuS microparticles are formed in the absence of any template under the identical experimental conditions. Raman studies show the characteristic peak of CdS and CuS, irrespective of their size and morphology. Finally, CdS and CuS of varying morphology have successfully been used as catalysts in UV photocatalytic decomposition of methylene blue dye. These findings show that CdS lotus-like microflowers are more effective catalysts than hierarchical stars, though the latter is found to have better reusability.Graphical AbstractA simple soft template-assisted and single complex source precursor-mediated solvothermal synthesis of CdS and CuS with a diverse set of morphology has been reported. In addition, the morphology and application in photocatalysis are also discussed.

Controllable architecture of CdS and CuS by single-source precursor-mediated approach and their photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Sahoo, Ashish K.; Srivastava, Suneel K., E-mail: sunil111954@yahoo.co.uk [Indian Institute of Technology Kharagpur, Department of Chemistry (India)

2013-04-15

The present work deals with the preparation of hexagonal CdS and CuS by solvothermal decomposition of the morpholine-4-carbdithioate (MCDT) complexes of Cd and Cu in a water/THF mixture at 140-180 Degree-Sign C for 24 h and characterization. Scanning electron microscopy, field emission scanning electron microscopy and high resolution transmission electron microscopy show that CdS exhibits a hierarchical star- and lotus flower-like morphology in the presence of disodium salt of ethylenediamine tetraaceticacid and sodium dodecyl benzene sulphonate as soft templates at 140 and 160 Degree-Sign C, respectively. However, Cu complex of MCDT forms CuS nanoparticles in the temperature range of 140-180 Degree-Sign C. On the contrary, CdS nanoparticles and CuS microparticles are formed in the absence of any template under the identical experimental conditions. Raman studies show the characteristic peak of CdS and CuS, irrespective of their size and morphology. Finally, CdS and CuS of varying morphology have successfully been used as catalysts in UV photocatalytic decomposition of methylene blue dye. These findings show that CdS lotus-like microflowers are more effective catalysts than hierarchical stars, though the latter is found to have better reusability.Graphical AbstractA simple soft template-assisted and single complex source precursor-mediated solvothermal synthesis of CdS and CuS with a diverse set of morphology has been reported. In addition, the morphology and application in photocatalysis are also discussed.

Solvothermal Synthesis of Three-Dimensional Hierarchical CuS Microspheres from a Cu-Based Ionic Liquid Precursor for High-Performance Asymmetric Supercapacitors.

Science.gov (United States)

Zhang, Jing; Feng, Huijie; Yang, Jiaqin; Qin, Qing; Fan, Hongmin; Wei, Caiying; Zheng, Wenjun

2015-10-07

It is meaningful to exploit copper sulfide materials with desired structure as well as potential application due to their cheapness and low toxicity. A low-temperature and facile solvothermal method for preparing three-dimensional (3D) hierarchical covellite (CuS) microspheres from an ionic liquid precursor [Bmim]2Cu2Cl6 (Bmim = 1-butyl-3-methylimidazolium) is reported. The formation of CuS nanostructures was achieved by decomposition of intermediate complex Cu(Tu)3Cl (thiourea = Tu), which produced CuS microspheres with diameters of 2.5-4 μm assembled by nanosheets with thicknesses of 10-15 nm. The ionic liquid, as an "all-in-one" medium, played a key role for the fabrication and self-assembly of CuS nanosheets. The alkylimidazolium rings ([Bmim](+)) were found to adsorb onto the (001) facets of CuS crystals, which inhibited the crystal growth along the [001] direction, while the alkyl chain had influence on the assembly of CuS nanosheets. The CuS microspheres showed enhanced electrochemical performance and high stability for the application in supercapacitors due to intriguing structural design and large specific surface area. When this well-defined CuS electrode was assembled into an asymmetric supercapacitor (ASC) with an activated carbon (AC) electrode, the CuS//AC-ASC demonstrated good cycle performance (∼88% capacitance after 4000 cycles) and high energy density (15.06 W h kg(-1) at a power density of 392.9 W kg(-1)). This work provides new insights into the use of copper sulfide electrode materials for asymmetric supercapacitors and other electrochemical devices.

A simple synthesis and characterization of CuS nanocrystals

Indian Academy of Sciences (India)

Unknown

Water-soluble CuS nanocrystals and nanorods were prepared by reacting copper acetate with thioacetamide in ... potential applications in solar cells, IR detectors and lubri- cation (Mane ... ted a solventless synthesis of Cu2S nanorods, by heating copper thiolate .... 2004 Nanoparticles: Building blocks for nano- technology ...

Expression and purification of recombinant proteins in Escherichia coli tagged with the metal-binding protein CusF.

Science.gov (United States)

Cantu-Bustos, J Enrique; Vargas-Cortez, Teresa; Morones-Ramirez, Jose Ruben; Balderas-Renteria, Isaias; Galbraith, David W; McEvoy, Megan M; Zarate, Xristo

2016-05-01

Production of recombinant proteins in Escherichia coli has been improved considerably through the use of fusion proteins, because they increase protein solubility and facilitate purification via affinity chromatography. In this article, we propose the use of CusF as a new fusion partner for expression and purification of recombinant proteins in E. coli. Using a cell-free protein expression system, based on the E. coli S30 extract, Green Fluorescent Protein (GFP) was expressed with a series of different N-terminal tags, immobilized on self-assembled protein microarrays, and its fluorescence quantified. GFP tagged with CusF showed the highest fluorescence intensity, and this was greater than the intensities from corresponding GFP constructs that contained MBP or GST tags. Analysis of protein production in vivo showed that CusF produces large amounts of soluble protein with low levels of inclusion bodies. Furthermore, fusion proteins can be exported to the cellular periplasm, if CusF contains the signal sequence. Taking advantage of its ability to bind copper ions, recombinant proteins can be purified with readily available IMAC resins charged with this metal ion, producing pure proteins after purification and tag removal. We therefore recommend the use of CusF as a viable alternative to MBP or GST as a fusion protein/affinity tag for the production of soluble recombinant proteins in E. coli. Copyright © 2016 Elsevier Inc. All rights reserved.

Electrocatalysis of hemoglobin in ionic liquid BMIMPF6 and CuS nanosphere composite films

Directory of Open Access Journals (Sweden)

Wei Sun

2011-12-01

Full Text Available Ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6 was mixed homogeneously with nanometer-sized semiconductor CuS sphere to form a new nanocomposite material, which was further used for the immobilization of hemoglobin (Hb on the surface of carbon paste electrode (CPE. Direct electrochemistry of Hb in BMIMPF6-CuS composite film was carefully investigated with a pair of quasi-reversible redox peaks appeared and the formal potential (E0' was got as -135 mV (vs. SCE in pH 7.0 phosphate buffer solution, which was due to the enhanced direct electron transfer rate of Hb in the biocompatible matrix. The BMIMPF6-CuS-Hb/CPE showed excellent electrocatalytic activity to the reduction of hydrogen peroxide with the kinetic parameters for the electrocatalytic reaction evaluated. The results indicated that the BMIMPF6-CuS nanocomposite could be used for the preparation of electrochemical biosensor.

Three-dimensional reconstructions of the bacteriophage CUS-3 virion reveal a conserved coat protein I-domain but a distinct tailspike receptor-binding domain

International Nuclear Information System (INIS)

Parent, Kristin N.; Tang, Jinghua; Cardone, Giovanni; Gilcrease, Eddie B.; Janssen, Mandy E.; Olson, Norman H.; Casjens, Sherwood R.; Baker, Timothy S.

2014-01-01

CUS-3 is a short-tailed, dsDNA bacteriophage that infects serotype K1 Escherichia coli. We report icosahedrally averaged and asymmetric, three-dimensional, cryo-electron microscopic reconstructions of the CUS-3 virion. Its coat protein structure adopts the “HK97-fold” shared by other tailed phages and is quite similar to that in phages P22 and Sf6 despite only weak amino acid sequence similarity. In addition, these coat proteins share a unique extra external domain (“I-domain”), suggesting that the group of P22-like phages has evolved over a very long time period without acquiring a new coat protein gene from another phage group. On the other hand, the morphology of the CUS-3 tailspike differs significantly from that of P22 or Sf6, but is similar to the tailspike of phage K1F, a member of the extremely distantly related T7 group of phages. We conclude that CUS-3 obtained its tailspike gene from a distantly related phage quite recently. - Highlights: • Asymmetric and symmetric three-dimensional reconstructions of phage CUS-3 are presented. • CUS-3 major capsid protein has a conserved I-domain, which is found in all three categories of “P22-like phage”. • CUS-3 has very different tailspike receptor binding domain from those of P22 and Sf6. • The CUS-3 tailspike likely was acquired by horizontal gene transfer

Three-dimensional reconstructions of the bacteriophage CUS-3 virion reveal a conserved coat protein I-domain but a distinct tailspike receptor-binding domain

Energy Technology Data Exchange (ETDEWEB)

Parent, Kristin N., E-mail: kparent@msu.edu [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); Tang, Jinghua; Cardone, Giovanni [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); Gilcrease, Eddie B. [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Janssen, Mandy E.; Olson, Norman H. [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); Casjens, Sherwood R., E-mail: sherwood.casjens@path.utah.edu [University of Utah School of Medicine, Division of Microbiology and Immunology, Department of Pathology, Salt Lake City, UT 84112 (United States); Baker, Timothy S., E-mail: tsb@ucsd.edu [Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093-0378 (United States); University of California, San Diego, Division of Biological Sciences, La Jolla, CA, 92093 (United States)

2014-09-15

CUS-3 is a short-tailed, dsDNA bacteriophage that infects serotype K1 Escherichia coli. We report icosahedrally averaged and asymmetric, three-dimensional, cryo-electron microscopic reconstructions of the CUS-3 virion. Its coat protein structure adopts the “HK97-fold” shared by other tailed phages and is quite similar to that in phages P22 and Sf6 despite only weak amino acid sequence similarity. In addition, these coat proteins share a unique extra external domain (“I-domain”), suggesting that the group of P22-like phages has evolved over a very long time period without acquiring a new coat protein gene from another phage group. On the other hand, the morphology of the CUS-3 tailspike differs significantly from that of P22 or Sf6, but is similar to the tailspike of phage K1F, a member of the extremely distantly related T7 group of phages. We conclude that CUS-3 obtained its tailspike gene from a distantly related phage quite recently. - Highlights: • Asymmetric and symmetric three-dimensional reconstructions of phage CUS-3 are presented. • CUS-3 major capsid protein has a conserved I-domain, which is found in all three categories of “P22-like phage”. • CUS-3 has very different tailspike receptor binding domain from those of P22 and Sf6. • The CUS-3 tailspike likely was acquired by horizontal gene transfer.

A high-response transparent heater based on a CuS nanosheet film with superior mechanical flexibility and chemical stability.

Science.gov (United States)

Xie, Shuyao; Li, Teng; Xu, Zijie; Wang, Yanan; Liu, Xiangyang; Guo, Wenxi

2018-04-05

Transparent heaters are widely used in technologies such as window defrosting/defogging, displays, gas sensing, and medical equipment. Apart from mechanical robustness and electrical and optical reliabilities, outstanding chemical stability is also critical to the application of transparent heaters. In this regard, we first present a highly flexible and large-area CuS transparent heater fabricated by a colloidal crackle pattern method with an optimized sheet resistance (Rs) as low as 21.5 Ω sq-1 at a ∼80% transmittance. The CuS transparent heater exhibits remarkable mechanical robustness during bending tests as well as high chemical stability against acid and alkali environments. In the application as a transparent heater, the CuS heater demonstrates a high thermal resistance of 197 °C W-1 cm2 with a fast switching time (solar panels. These CuS network TCEs with high flexibility, transparency, conductivity, and chemical stability could be widely used in wearable electronic products.

Electrocatalysis of hemoglobin in ionic liquid BMIMPF 6 and CuS ...

African Journals Online (AJOL)

The results indicated that the BMIMPF6-CuS nanocomposite could be used for the preparation of electrochemical biosensor. KEY WORDS: Hemoglobin, Direct electrochemistry, Copper sulfide nanosphere, 1-Butyl-3-methylimidazolium hexafluorophosphate, Hydrogen peroxide. Bull. Chem. Soc. Ethiop. 2011, 25(3) ...

Laser-induced construction of multi-branched CuS nanodendrites with excellent surface-enhanced Raman scattering spectroscopy in repeated applications.

Science.gov (United States)

Li, Shuang; Zhang, Hua; Xu, Linlin; Chen, Ming

2017-07-10

We report on the successful fabrication of multi-branched CuS nanodendrites with average branch length of about 20 nm by laser ablation of bulk Cu target in thioacetamide (TAA) solution. During the nucleation of Cu and S species, the accurate anisotropic growth should be attributed to an ultra-rapid acid etching process by laser-induced TAA hydrolyzing reaction. Interestingly, the semiconductor CuS nanodendrites provide pronounced surface enhanced Raman scattering (SERS) properties with noble-metal comparable activity and a detection limit as low as ~10 -10 M, approaching the requirement (~nM) for single molecule detection. More importantly, after SERS analysis, the crystal violet (CV) probe molecules can be effectively removed from the substrate by 1064nm laser irradiation-induced moderate thermal treatment. Therefore, the unique and distinctive advantage is that the as-prepared CuS nanodendrites exhibit excellent reusability for 60 cycles of repeated SERS analyses. The low-cost CuS semiconductor nanodendrites with enhanced SERS properties should be established as a prominent SERS-based ultrasensitive probe in the repeated applications.

Draft genome sequence of Acidithiobacillus ferrooxidans YQH-1

Directory of Open Access Journals (Sweden)

Lei Yan

2015-12-01

Full Text Available Acidithiobacillus ferrooxidans YQH-1 is a moderate acidophilic bacterium isolated from a river in a volcano of Northeast China. Here, we describe the draft genome of strain YQH-1, which was assembled into 123 contigs containing 3,111,222 bp with a G + C content of 58.63%. A large number of genes related to carbon dioxide fixation, dinitrogen fixation, pH tolerance, heavy metal detoxification, and oxidative stress defense were detected. The genome sequence can be accessed at DDBJ/EMBL/GenBank under the accession no. LJBT00000000.

Adaptación de una cepa compatible con Acidithiobacillus ferrooxidans sobre concentrados de calcopirita (CuFeS2, esfalerita (ZnS y galena (PbS

Directory of Open Access Journals (Sweden)

E Mejía

2011-01-01

In this study the adaptation of Acidithiobacillus ferrooxidans-like to high concentrations of chalcopyrite, sphalerite and galena were evaluated with two mineral-particle sizes: 200 and 325 Tyler mesh. The strain was adapted using two simultaneous processes. The first one consisted in a gradual decreasing of the main energy source, ferrous sulphate. The second one consisted in a gradual increasing of the mineral content. Finally, a test was made without ferrous sulphate. The serial subculturing was found to be an efficient strategy to adapt Acidithiobacillus ferrooxidans-like to higher concentrations of chalcopyrite, sphalerite and galena. This indicates that a suitable protocol was employed. The results showed that Acidithiobacillus ferrooxidans-like is more resistant to high concentration of sphalerite, chalcopyrite and galena in descendant order. The particle size played an important role in the adaption of microorganism to the mineral. Key words: Sphalerite, chalcopyrite, galena, adapting, Acidithiobacillus ferrooxidans, bioleaching.

Community dynamics of attached and free cells and the effects of attached cells on chalcopyrite bioleaching by Acidithiobacillus sp.

Science.gov (United States)

Yang, Hailin; Feng, Shoushuai; Xin, Yu; Wang, Wu

2014-02-01

The community dynamics of attached and free cells of Acidithiobacillus sp. were investigated and compared during chalcopyrite bioleaching process. In the mixed strains system, Acidithiobacillus ferrooxidans was the dominant species at the early stage while Acidithiobacillus thiooxidans owned competitive advantage from the middle stage to the end of bioprocess. Meanwhile, compared to A. ferrooxidans, more significant effects of attached cells on free biomass with A. thiooxidans were shown in either the pure or mixed strains systems. Moreover, the effects of attached cells on key chemical parameters were also studied in different adsorption-deficient systems. Consistently, the greatest reduction of key chemical ion was shown with A. thiooxidans and the loss of bioleaching efficiency was high to 50.5%. These results all demonstrated the bioleaching function of attached cells was more efficient than the free cells, especially with A. thiooxidans. These notable results would help us to further understand the chalcopyrite bioleaching. Copyright © 2013 Elsevier Ltd. All rights reserved.

Depositing of CuS nanocrystals upon the graphene scaffold and their photocatalytic activities

Science.gov (United States)

Wang, Yongbin; Zhang, Lixin; Jiu, Hongfang; Li, Na; Sun, Yixin

2014-06-01

A series of copper sulfide nanocrystals/graphene nanocomposites (CuS/GR) with different weight ratios of GR were fabricated via a one-step hydrothermal approach by using dimethylsulfoxide (DMSO) as the source of sulfur and solvent. The as-prepared samples were studied by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (DRS), transmission scanning electron microscopy (TEM) and photoluminescence spectra (PL) are employed to determine the properties of the samples. The results show that the CuS nanocrystals with an average size of 16 nm almost overspread on the GR graphene scaffold. The samples exhibit excellent photocatalytic activities in degrading the methylene blue (MB) compared with pure CuS. This work shows that CuS/GR nanocomposites would be promising in dye wastewater treatment as Fenton-like reagents.

Depositing of CuS nanocrystals upon the graphene scaffold and their photocatalytic activities

International Nuclear Information System (INIS)

Wang, Yongbin; Zhang, Lixin; Jiu, Hongfang; Li, Na; Sun, Yixin

2014-01-01

A series of copper sulfide nanocrystals/graphene nanocomposites (CuS/GR) with different weight ratios of GR were fabricated via a one-step hydrothermal approach by using dimethylsulfoxide (DMSO) as the source of sulfur and solvent. The as-prepared samples were studied by X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (DRS), transmission scanning electron microscopy (TEM) and photoluminescence spectra (PL) are employed to determine the properties of the samples. The results show that the CuS nanocrystals with an average size of 16 nm almost overspread on the GR graphene scaffold. The samples exhibit excellent photocatalytic activities in degrading the methylene blue (MB) compared with pure CuS. This work shows that CuS/GR nanocomposites would be promising in dye wastewater treatment as Fenton-like reagents.

Depositing of CuS nanocrystals upon the graphene scaffold and their photocatalytic activities

Energy Technology Data Exchange (ETDEWEB)

Wang, Yongbin [Chemical Engineering and Environment Institute, North University of China, Taiyuan 030051 (China); Zhang, Lixin, E-mail: edwardzlx@163.com [Chemical Engineering and Environment Institute, North University of China, Taiyuan 030051 (China); Jiu, Hongfang [College of Science, North University of China, Taiyuan 030051 (China); Li, Na; Sun, Yixin [Chemical Engineering and Environment Institute, North University of China, Taiyuan 030051 (China)

2014-06-01

A series of copper sulfide nanocrystals/graphene nanocomposites (CuS/GR) with different weight ratios of GR were fabricated via a one-step hydrothermal approach by using dimethylsulfoxide (DMSO) as the source of sulfur and solvent. The as-prepared samples were studied by X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (DRS), transmission scanning electron microscopy (TEM) and photoluminescence spectra (PL) are employed to determine the properties of the samples. The results show that the CuS nanocrystals with an average size of 16 nm almost overspread on the GR graphene scaffold. The samples exhibit excellent photocatalytic activities in degrading the methylene blue (MB) compared with pure CuS. This work shows that CuS/GR nanocomposites would be promising in dye wastewater treatment as Fenton-like reagents.

Sulfur Oxygenase Reductase (Sor) in the Moderately Thermoacidophilic Leaching Bacteria: Studies in Sulfobacillus thermosulfidooxidans and Acidithiobacillus caldus

Science.gov (United States)

Janosch, Claudia; Remonsellez, Francisco; Sand, Wolfgang; Vera, Mario

2015-01-01

The sulfur oxygenase reductase (Sor) catalyzes the oxygen dependent disproportionation of elemental sulfur, producing sulfite, thiosulfate and sulfide. Being considered an “archaeal like” enzyme, it is also encoded in the genomes of some acidophilic leaching bacteria such as Acidithiobacillus caldus, Acidithiobacillus thiooxidans, Acidithiobacillus ferrivorans and Sulfobacillus thermosulfidooxidans, among others. We measured Sor activity in crude extracts from Sb. thermosulfidooxidans DSM 9293T. The optimum temperature for its oxygenase activity was achieved at 75 °C, confirming the “thermophilic” nature of this enzyme. Additionally, a search for genes probably involved in sulfur metabolism in the genome sequence of Sb. thermosulfidooxidans DSM 9293T was done. Interestingly, no sox genes were found. Two sor genes, a complete heterodisulfidereductase (hdr) gene cluster, three tetrathionate hydrolase (tth) genes, three sulfide quinonereductase (sqr), as well as the doxD component of a thiosulfate quinonereductase (tqo) were found. Seven At. caldus strains were tested for Sor activity, which was not detected in any of them. We provide evidence that an earlier reported Sor activity from At. caldus S1 and S2 strains most likely was due to the presence of a Sulfobacillus contaminant. PMID:27682113

Expression, purification and molecular structure modeling of thioredoxin (Trx) and thioredoxin reductase (TrxR) from Acidithiobacillus ferrooxidans.

Science.gov (United States)

Wang, Yiping; Zhang, Xiaojian; Liu, Qing; Ai, Chenbing; Mo, Hongyu; Zeng, Jia

2009-07-01

The thioredoxin system consists of thioredoxin (Trx), thioredoxin reductase (TrxR) and NADPH, which plays several key roles in maintaining the redox environment of the cell. In Acidithiobacillus ferrooxidans, thioredoxin system may play important functions in the activity regulation of periplasmic proteins and energy metabolism. Here, we cloned thioredoxin (trx) and thioredoxin reductase (trxR) genes from Acidithiobacillus ferrooxidans, and expressed the genes in Escherichia coli. His-Trx and His-TrxR were purified to homogeneity with one-step Ni-NTA affinity column chromatography. Site-directed mutagenesis results confirmed that Cys33, Cys36 of thioredoxin, and Cys142, Cys145 of thioredoxin reductase were active-site residues.

Optical and Electrical Properties of Thin Films of CuS Nanodisks Ensembles Annealed in a Vacuum and Their Photocatalytic Activity

Directory of Open Access Journals (Sweden)

J. Santos Cruz

2013-01-01

Full Text Available Effects on the optical, electrical, and photocatalytic properties of undoped CuS thin films nanodisks vacuum annealed at different temperatures were investigated. The chemical bath prepared CuS thin films were obtained at 40°C on glass substrates. The grain size of 13.5±3.5 nm was computed directly from high-resolution transmission electron microscopy (HRTEM images. The electrical properties were measured by means of both Hall effect at room temperature and dark resistivity as a function of the absolute temperature 100–330 K. The activation energy values were calculated as 0.007, 0.013, and 0.013 eV for 100, 150, and 200°C, respectively. The energy band gap of the films varied in the range of 1.98 up to 2.34 eV. The photocatalytic activity of the CuS thin film was evaluated by employing the degradation of aqueous methylene blue solution in the presence of hydrogen peroxide. The CuS sample thin film annealed in vacuum at 150°C exhibited the highest photocatalytic activity in presence of hydrogen peroxide.

Enhanced electrochemical capacitance of polyimidazole coated covellite CuS dispersed CNT composite materials for application in supercapacitors.

Science.gov (United States)

Ravi, Seenu; Gopi, Chandu V V M; Kim, Hee Je

2016-08-02

Great attention has been paid to the design and synthesis of distinct core/shell heterostructures for high-performance supercapacitors. We have prepared unique heterostructures consisting of polyimidazole-coated copper sulphide over a carbon nanotube network (CuS@CNT) on nickel foam, which was accomplished through a facile and cost-effective solvothermal method combined with a dip coating process. Hexagonal covellite CuS nanoparticles were dispersed on CNTs using a solvothermal method where dimethylformamide and distilled water were used as solvents. The synthesized CuS and CuS@CNT supercapacitor electrode materials were thoroughly characterized. The polymer supported electrode (PIM/CuS@CNT) shows a high areal capacitance of 1.51 F cm(-2) at a current density of 1.2 A g(-1), which is higher than the CuS@CNT electrode and many other previously reported CuS electrode materials. After 1000 cycles at a high current density of 1.2 A g(-1), the retention rate is 92%, indicating good long-term cycling stability. These results indicate that the PIM/CuS@CNT electrode is promising for high-performance supercapacitor applications.

[Effect of simulated heavy metal leaching solution of electroplating sludge on the bioactivity of Acidithiobacillus ferrooxidans].

Science.gov (United States)

Xie, Xin-Yuan; Sun, Pei-De; Lou, Ju-Qing; Guo, Mao-Xin; Ma, Wang-Gang

2013-01-01

An Acidithiobacillus ferrooxidans strain WZ-1 was isolated from the tannery sludge in Wenzhou, Zhejiang Province in China. The cell of WZ-1 strain is Gram negative and rod-shaped, its 16S rDNA sequence is closely related to that of Acidithiobacillus ferrooxidans ATCC23270 with 99% similarity. These results reveal that WZ-1 is a strain of Acidithiobacillus ferrooxidans. The effects of Ni2+, Cr3+, Cu2+, Zn2+ and 5 kinds of simulated leaching solutions of electroplating sludge on the bioactivity of Fe2+ oxidation and apparent respiratory rate of WZ-1 were investigated. The results showed that Ni2+ and Cr3+ did not have any influence on the bioactivity of WZ-1 at concentrations of 5.0 g x L(-1) and 0.1 g x L(-1), respectively. WZ-1 showed tolerance to high levels of Ni2+, Zn2+ (about 30.0 g x L(-1)), but it had lower tolerance to Cr3+ and Cu2+ (0.1 g x L(-1) Cr3+ and 2.5 g x L(-1) Cu2+). Different kinds of simulated leaching solution of electroplating sludge had significant differences in terms of their effects on the bioactivity of WZ-1 with a sequence of Cu/Ni/Cr/Zn > Cu/Ni/Zn > Cu/Cr/Zn > Cu/Ni/Cr > Ni/Cr/Zn.

Nanoporous CuS nano-hollow spheres as advanced material for high-performance supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Heydari, Hamid [Faculty of Sciences, Razi University, Kermanshah (Iran, Islamic Republic of); Moosavifard, Seyyed Ebrahim, E-mail: info_seyyed@yahoo.com [Young Researchers and Elite Club, Central Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Elyasi, Saeed [Department of Chemical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Shahraki, Mohammad [Department of Chemistry, University of Sistan and Baluchestan, Zahedan (Iran, Islamic Republic of)

2017-02-01

Highlights: • Nanoporous CuS nano-hollow spheres were synthesized by a facile method. • Nano-hollow spheres have a large specific surface area (97 m{sup 2} g{sup −1}) and nanoscale shell thickness (<20 nm). • Such unique structures exhibit excellent electrochemical properties for high-performance SCs. - Abstract: Due to unique advantages, the development of high-performance supercapacitors has stimulated a great deal of scientific research over the past decade. The electrochemical performance of a supercapacitor is strongly affected by the surface and structural properties of its electrode materials. Herein, we report a facile synthesis of high-performance supercapacitor electrode material based on CuS nano-hollow spheres with nanoporous structures, large specific surface area (97 m{sup 2} g{sup −1}) and nanoscale shell thickness (<20 nm). This interesting electrode structure plays a key role in providing more active sites for electrochemical reactions, short ion and electron diffusion pathways and facilitated ion transport. The CuS nano-hollow spheres electrode exhibits excellent electrochemical performance including a maximum specific capacitance of 948 F g{sup −1} at 1 A g{sup −1}, significant rate capability of 46% capacitance retention at a high current density of 50 A g{sup −1}, and outstanding long-term cycling stability at various current densities. This work not only demonstrates the promising potential of the CuS-NHS electrodes for application in high-performance supercapacitors, but also sheds a new light on the metal sulfides design philosophy.

Peningkatan Nilai-Nilai Karakter Dengan Metode Mendongeng CAS CIS CUS Di BA Aisyiyah Kaponan 2 Ponorogo

Directory of Open Access Journals (Sweden)

Sidik Nuryanto

2017-03-01

Full Text Available Tujuan penelitian ini adalah melihat pelaksanaan mendongeng CAS CIS CUS dan peningkatan nilai karakter di BA ‘Aisyiyah Kaponan 2 Ponorogo. Penelitian ini dilaksanakan dengan subjek sejumlah 18 peserta didik. Metode penelitian menggunakan penelitian tindakan kelas. Prosedurnya meliputi perencanaan, pelaksanaan, pengamatan dan refleksi. Sumber data berupa informan, tempat dan peristiwa, dokumen dan arsip. Metode pengumpulan data dengan teknik wawancara, observasi, dan dokumentasi. Uji validitas data yang digunakan dengan teknik triangulasi. Data dianalisis dengan menggunakan model deskriptif komparatif.       Hasilnya pada kegiatan mendongeng dibagi menjadi 3 tahapan yaitu CAS CIS CUS. CAS (Cipta Aksi Super sebagai sarana untuk membuka dongeng, CIS (Cipta Inspirasi Super sebagai inti dari pelaksanaan dongeng, dan CUS (Cipta Usulan Super sebagai penutup dongeng. Pada pra siklus nilai karakter kecintaan terhadap Tuhan yang mulanya 68,8% pada siklus I menjadi 75%, dan pada siklus II 87,5%. Nilai disiplin anak pada kondisi awal 62,5% meningkat menjadi 68,8% dan akhir siklus II mencapai 93,8%. Nilai kemandirian terus meningkat dari 68,8% lalu 81,3% dan menjadi 93,8%. Nilai kerjasama bermula dari 56,3% pada siklus I menjadi 75% dan siklus II menjadi 81,3%. Tanggungjawab pada keadaan awal 56,3% berubah menjadi 68,8% serta siklus II menjadi 87,5%.The purpose of this study is to see the implementation of the CIS CAS CUS storytelling and character value increase in BA 'Aisyiyah Kaponan 2 Ponorogo. This study was conducted with 18 subjects number of learners. The research method uses classroom action research. The procedure includes the planning, implementation, observation and reflection. Sources of data in the form of informants, places and events, documents and archives. Data were collected by interview, observation and documentation. Test the validity of the data used by triangulation techniques. Data were analyzed using descriptive comparative

Fabrication of mesoporous iron (Fe) doped copper sulfide (CuS) nanocomposite in the presence of a cationic surfactant via mild hydrothermal method for supercapacitors

Science.gov (United States)

Brown, J. William; Ramesh, P. S.; Geetha, D.

2018-02-01

We report fabrication of mesoporous Fe doped CuS nanocomposites with uniform mesoporous spherical structures via a mild hydrothermal method employing copper nitrate trihydrate (Cu (NO3).3H2O), Thiourea (Tu,Sc(NH2)2 and Iron tri nitrate (Fe(No3)3) as initial materials with cationic surfactant cetyltrimethylamoniame bromide (CTAB) as stabilizer/size controller and Ethylene glycol as solvent at 130 °C temperature. The products were characterized by XRD, SEM/EDX, TEM, FTIR and UV analysis. X-ray diffraction (XRD) spectra confirmed the Fe doped CuS nanocomposites which are crystalline in nature. EDX and XRD pattern confirmed that the product is hexagonal CuS phase. Fe doped spherical structure of CuS with grain size of 21 nm was confirmed by XRD pattern. Fe doping was identified by energy dispersive spectrometry (EDS). The Fourier-transform infrared (FTIR) spectroscopy results revealed the occurrence of active functional groups required for the reduction of copper ions. Studies showed that after a definite time relining on the chosen copper source, the obtained Fe-CuS nanocomposite shows a tendency towards self-assembly and creating mesoporous like nano and submicro structures by TEM/SAED. The achievable mechanism of producing this nanocomposite was primarily discussed. The electrochemical study confirms the pseudocapacitive nature of the CuS and Fe-CuS electrodes. The CuS and Fe-CuS electrode shows a specific capacitance of about 328.26 and 516.39 Fg-1 at a scan rate of 5 mVs-1. As the electrode in a supercapacitor, the mesoporous nanostructured Fe-CuS shows excellent capacitance characteristics.

CuInS2 thin films obtained through the annealing of chemically deposited In2S3-CuS thin films

International Nuclear Information System (INIS)

Pena, Y.; Lugo, S.; Calixto-Rodriguez, M.; Vazquez, A.; Gomez, I.; Elizondo, P.

2011-01-01

In this work, we report the formation of CuInS 2 thin films on glass substrates by heating chemically deposited multilayers of copper sulfide (CuS) and indium sulfide (In 2 S 3 ) at 300 and 350 deg. C in nitrogen atmosphere at 10 Torr. CIS thin films were prepared by varying the CuS layer thickness in the multilayers with indium sulfide. The XRD analysis showed that the crystallographic structure of the CuInS 2 (JCPDS 27-0159) is present on the deposited films. From the optical analysis it was estimated the band gap value for the CIS film (1.49 eV). The electrical conductivity varies from 3 x 10 -8 to 3 Ω -1 cm -1 depending on the thickness of the CuS film. CIS films showed p-type conductivity.

Impact of solvent extraction organics on bioleaching by Acidithiobacillus ferrooxidans

Science.gov (United States)

Yu, Hualong; Liu, Xiaorong; Shen, Junhui; Chi, Daojie

2017-03-01

Solvent extraction organics (SX organics) entrained and dissoluted in the raffinate during copper SX operation, can impact bioleaching in case of raffinate recycling. The influence of SX organics on bioleaching process by Acidithiobacillus ferrooxidans (At. ferrooxidans) has been investigated. The results showed that, cells of At. ferrooxidans grew slower with contaminated low-grade chalcopyrite ores in shaken flasks bioleaching, the copper bioleaching efficiency reached 15%, lower than that of 24% for uncontaminated minerals. Obviously, the SX organics could adsorb on mineral surface and hinder its contact with bacterials, finanlly lead to the low bioleaching efficiency.

Bioflotation of sulfide minerals with Acidithiobacillus ferrooxidans in relation to copper activation and surface oxidation.

Science.gov (United States)

Pecina-Treviño, E T; Ramos-Escobedo, G T; Gallegos-Acevedo, P M; López-Saucedo, F J; Orrantia-Borunda, E

2012-09-01

Surface oxidation of sulfides and copper (Cu) activation are 2 of the main processes that determine the efficiency of flotation. The present study was developed with the intention to ascertain the role of the phenomena in the biomodification of sulfides by Acidithiobacillus ferrooxidans culture (cells and growth media) and their impact in bioflotation. Surface characteristics of chalcopyrite, sphalerite, and pyrrhotite, alone and in mixtures, after interaction with A. ferrooxidans were evaluated. Chalcopyrite floatability was increased substantially by biomodification, while bacteria depressed pyrrhotite floatability, favoring separation. The results showed that elemental sulfur concentration increased because of the oxidation generated by bacterial cells, the effect is intensified by the Fe(III) left in the culture and by galvanic contact. Acidithiobacillus ferrooxidans culture affects the Cu activation of sphalerite. The implications of elemental sulfur concentration and Cu activation of sphalerite are key factors that must be considered for the future development of sulfide bioflotation processes, since the depressive effect of cells could be counteracted by elemental sulfur generation.

O lócus enunciativo do sujeito subalterno: fala e emudecimento

Directory of Open Access Journals (Sweden)

Tayane Rogeria Lino

2015-05-01

Full Text Available O artigo busca investigar a fala/silêncio dos sujeitos, tendo como objetivo estabelecer uma discussão em torno do complexo debate acerca do lócus enunciativo do sujeito subalterno na vida social contemporânea, principalmente, no campo científico. Foram tomadas como foco deste trabalho as contribuições da teórica Gayatri Chakravorty Spivak (2010 no texto “Pode o subalterno falar?”, onde a autora afirma que os subalternos são aqueles que não participam, ou participam de modo muito limitado, sendo sujeitos mudos pelo imperialismo cultural e pela violência epistemológica. Não há um consenso sobre o cunho propositivo ou sobre a resignação nas teorizações de Spivak (2010. Inúmeras críticas são feitas ao pensamento da intelectual. Se por um lado alguns vão nomear as proposições de Gayatri como uma teórica que não propõe nenhuma saída da condição de inferiorização dos subalternos. Outros vão pontuar que ela assume uma postura firme e corajosa ao afirmar que a responsabilidade pelo combate à subalternidade é papel dos intelectuais. O ponto central deste ensaio é a busca por estruturas teóricas, textuais, sociais e políticas que possam propiciar a emergência de vozes que foram silenciadas por forças políticas imperialistas. Para tanto contou-se como aporte teórico os Estudos Subalternos sul-asiáticos e Pós-coloniais questionou-se sobre estes novos sujeitos da produção científica e sua enunciação. Esse campo teórico apresentou-se como uma importante contribuição para o campo científico, pois, traz o “outro” para a cena, o não falante, o silenciado, o que sempre ocupou o lugar de sujeito na ciência e, poucas vezes, o de sujeito da ciência.

Insights into the relation between adhesion force and chalcopyrite-bioleaching by Acidithiobacillus ferrooxidans.

Science.gov (United States)

Zhu, Jianyu; Wang, Qianfen; Zhou, Shuang; Li, Qian; Gan, Min; Jiang, Hao; Qin, Wenqing; Liu, Xueduan; Hu, Yuehua; Qiu, Guanzhou

2015-02-01

This paper presents a study on the relation between bacterial adhesion force and bioleaching rate of chalcopyrite, which sheds light on the influence of interfacial interaction on bioleaching behavior. In our research, Acidithiobacillus ferrooxidans (A. ferrooxidans) were adapted to grow with FeSO4 · 7H2O, element sulfur or chalcopyrite. Then, surface properties of Acidithiobacillus ferrooxidans and chalcopyrite were analyzed by contact angle, zeta potential and Fourier transform infrared spectroscopy (FTIR). Adhesion force between bacteria and chalcopyrite was measured by atomic force microscopy (AFM). Attachment and bioleaching behaviors were also monitored. The results showed that A. ferrooxidans adapted with chalcopyrite exhibited the strongest adhesion force to chalcopyrite and the highest bioleaching rate. Culture adapted with sulfur bacteria took second place and FeSO4 · 7H2O-adapted bacteria were the lowest. Bioleaching rate and bacterial attachment capacity were positively related to bacterial adhesion force, which is affected by the nature of energy source. According to this work, the attachment of bacteria to chalcopyrite surface is one of the most important aspects that influence the bioleaching process of chalcopyrite. Copyright © 2014 Elsevier B.V. All rights reserved.

Anisotropic localized surface plasmon resonances in CuS nanoplates prepared by size-selective precipitation

Science.gov (United States)

Hamanaka, Yasushi; Yamada, Kaoru; Hirose, Tatsunori; Kuzuya, Toshihiro

2018-05-01

CuS nanoplates were synthesized by a colloidal method and separated into four fractions of nanoplates with different aspect ratios by a size-selective precipitation. In addition to a strong near infrared absorption band ascribed to the in-plane mode of the localized surface plasmon resonance (LSPR), we found a weak absorption band on the high frequency tail of the in-plane LSPR band. The frequency of the weak absorption band was almost constant and independent of the aspect ratio, while the in-plane LSPR band exhibited a strong aspect ratio dependence. These characteristics suggested that the weak absorption band is ascribed to the out-of-plane LSPR. Although the out-of-plane LSPR was expected to be difficult to observe for CuS nanoplates due to its low intensity and overlap with the strong in-plane resonance, we could successfully identify the out-of-plane mode by reducing the width of the size distribution and spectral broadening caused thereby.

Chemical bath deposited and dip coating deposited CuS thin films - Structure, Raman spectroscopy and surface study

Science.gov (United States)

Tailor, Jiten P.; Khimani, Ankurkumar J.; Chaki, Sunil H.

2018-05-01

The crystal structure, Raman spectroscopy and surface microtopography study on as-deposited CuS thin films were carried out. Thin films deposited by two techniques of solution growth were studied. The thin films used in the present study were deposited by chemical bath deposition (CBD) and dip coating deposition techniques. The X-ray diffraction (XRD) analysis of both the as-deposited thin films showed that both the films possess covellite phase of CuS and hexagonal unit cell structure. The determined lattice parameters of both the films are in agreement with the standard JCPDS as well as reported data. The crystallite size determined by Scherrer's equation and Hall-Williamsons relation using XRD data for both the as-deposited thin films showed that the respective values were in agreement with each other. The ambient Raman spectroscopy of both the as-deposited thin films showed major emission peaks at 474 cm-1 and a minor emmision peaks at 265 cm-1. The observed Raman peaks matched with the covellite phase of CuS. The atomic force microscopy of both the as-deposited thin films surfaces showed dip coating thin film to be less rough compared to CBD deposited thin film. All the obtained results are presented and deliberated in details.

Effects of chronic stress on the brain – the evidence from morphological examinations of hippocampus in a chronic unpredictable stress (CUS model in rats

Directory of Open Access Journals (Sweden)

Joanna Sekita-Krzak

2016-12-01

    Abstract Background. Chronic stress exposure deteriorates memory and increases the risk of psychiatric disorders, including depression. Objectives. The objective of this study was to perform morphological studies in experimental model of neuropsychiatric disorder and to assess histologically the effect of chronic unpredictable stress procedure (CUS influence on hippocampus. Material and methods. Chronic unpredictable stress procedure (CUS was applied for 8 weeks in rats by the modified method described by Katz et al. Experimental model of neuropsychiatric disorder was used based on morphological studies of hippocampal formation. Results. Stress-induced alterations were observed in the hippocampus. Nerve cell changes included  neuron shrinkage and dendritic remodeling. The most vulnerable hippocampal cells to chronic stress were CA3 and CA4 pyramidal neurons. In dentate gyrus chronic stress led to granule neuron shrinkage and slight exacerbation of apoptosis in the polygonal cell layer. CUS led to statistically significant changes in quantitative characteristics of the CA3 and CA4 neuron size and nuclei diameter. Conclusions. Chronic stress induces degeneration of hippocampal neurons. The observed neuronal changes indicate the damage of the neurons did not involve neither apoptosis nor necrosis Similarity between histological changes obtained in 8-week long CUS procedure applied in our research and morphological changes described in depressed patients confirms the usefulness of the applied stress procedure as the experimental model of depression.   Key words: stress, depression, hippocampus, chronic unpredictable stress procedure (CUS, animal model, morphology.

A 4Σ1/2-X2Π1/2 transition in the electronic spectrum of the CuS molecule

International Nuclear Information System (INIS)

Lefebvre, Y.; Delaval, J.M.; Schamps, J.

1991-01-01

The (0-0) band of a new 4 Σ 1/2 -X 2 Π 1/2 transition has been observed in the hollow cathode emission spectra of the CuS molecule. Rotational analysis provides the following molecular constants (in cm -1 ) for the D 4 Σ 1/2 state: T 0 = 23112.88; B 0 = 0.17453; p 0 = 0.858; p 0j = 3.3x10 -6 ; D 0 = 0.11x10 -6 . Pulsed dye laser fluorescence experiments confirm the general diagram of the observed CuS electronic states. (orig.)

Electrochemical synthesis of nanoplatelets-like CuS0.2Se0.8 thin film for photoluminescence applications

Directory of Open Access Journals (Sweden)

Sharma A. K.

2015-06-01

Full Text Available Copper sulfide-selenide (CuS0.2Se0.8 thin films were deposited on FTO coated glass substrate (fluorine doped tin oxide and stainless steel substrates using electrodeposition technique. Deposited thin films were characterized using different characterization techniques viz. X-ray diffraction (XRD, scanning electron microscopy (SEM, UV-Vis spectroscopy, photoluminescence spectroscopy and surface wettability. XRD study showed polycrystalline nature with cubic phase of the films. Scanning electron microscopy showed that the surface area of the substrate was covered by the nanoplatelets structure of a thickness of 140 to 150 nm and optical study showed that the direct band gap was ~1.90 eV. Surface wettability showed hydrophobic nature of the CuS0.2Se0.8 thin films.

Controlled synthesis and characterization of covellite (CuS) nanoflakes

Energy Technology Data Exchange (ETDEWEB)

Zhang, H.T. [Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wu, G. [Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Chen, X.H. [Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)]. E-mail: chenxh@ustc.edu.cn

2006-08-01

Trigonal and hexagonal CuS (covellite) nanoflakes with controlled size (10-200 nm, and thickness of 3.6-5 nm) were synthesized through the reaction between copper acetylacetonate and sulfur in oleylamine. Size and shape of the products could be tuned by reaction parameters and reactant concentration. The as-prepared flakes have smooth surfaces and self-assemble face-to-face each other. High-resolution transmission electron microscopy and electron diffraction show that the nanoscale flakes were single-crystal hexagonal covellite. Formation mechanism of the nanoflakes is discussed. UV-vis spectra reveal that the samples have blue-shift absorbance onsets owning to the quantum size effects.

Controlled synthesis and characterization of covellite (CuS) nanoflakes

International Nuclear Information System (INIS)

Zhang, H.T.; Wu, G.; Chen, X.H.

2006-01-01

Trigonal and hexagonal CuS (covellite) nanoflakes with controlled size (10-200 nm, and thickness of 3.6-5 nm) were synthesized through the reaction between copper acetylacetonate and sulfur in oleylamine. Size and shape of the products could be tuned by reaction parameters and reactant concentration. The as-prepared flakes have smooth surfaces and self-assemble face-to-face each other. High-resolution transmission electron microscopy and electron diffraction show that the nanoscale flakes were single-crystal hexagonal covellite. Formation mechanism of the nanoflakes is discussed. UV-vis spectra reveal that the samples have blue-shift absorbance onsets owning to the quantum size effects

CuS p-type thin film characterization deposited on Ti, ITO and glass substrates using spray pyrolysis deposition (SPD) for light emitting diode (LED) application

Energy Technology Data Exchange (ETDEWEB)

Sabah, Fayroz A., E-mail: fayroz-arif@yahoo.com [Institue of Nano-Optoelectronics Research and Technology (INOR), School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Department of Electrical Engineering, College of Engineering, Al-Mustansiriya University, Baghdad (Iraq); Ahmed, Naser M., E-mail: naser@usm.my; Hassan, Z., E-mail: zai@usm.my; Azzez, Shrook A. [Institue of Nano-Optoelectronics Research and Technology (INOR), School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Rasheed, Hiba S., E-mail: hibasaad1980@yahoo.com [Institue of Nano-Optoelectronics Research and Technology (INOR), School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Department of Physics, College of Education, Al-Mustansiriya University, Baghdad (Iraq); Al-Hazim, Nabeel Z., E-mail: nabeelnano333@gmail.com [Institue of Nano-Optoelectronics Research and Technology (INOR), School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Ministry of Education, the General Directorate for Educational Anbar (Iraq)

2016-07-06

The copper sulphide (CuS) thin films were grown with good adhesion by spray pyrolysis deposition (SPD) on Ti, ITO and glass substrates at 200 °C. The distance between nozzle and substrate is 30 cm. The composition was prepared by mixing copper chloride CuCl{sub 2}.2H{sub 2}O as a source of Cu{sup 2+} and sodium thiosulfate Na{sub 2}S{sub 2}O{sub 3}.5H{sub 2}O as a source of and S{sup 2−}. Two concentrations (0.2 and 0.4 M) were used for each CuCl{sub 2} and Na{sub 2}S{sub 2}O{sub 3} to be prepared and then sprayed (20 ml). The process was started by spraying the solution for 3 seconds and after 10 seconds the cycle was repeated until the solution was sprayed completely on the hot substrates. The structural characteristics were studied using X-ray diffraction; they showed covellite CuS hexagonal crystal structure for 0.2 M concentration, and covellite CuS hexagonal crystal structure with two small peaks of chalcocite Cu{sub 2}S hexagonal crystal structure for 0.4 M concentration. Also the surface and electrical characteristics were investigated using Field Emission Scanning Electron Microscopy (FESEM) and current source device, respectively. The surface study for the CuS thin films showed nanorods to be established for 0.2 M concentration and mix of nanorods and nanoplates for 0.4 M concentration. The electrical study showed ohmic behavior and low resistivity for these films. Hall Effect was measured for these thin films, it showed that all samples of CuS are p- type thin films and ensured that the resistivity for thin films of 0.2 M concentration was lower than that of 0.4 M concentration; and for the two concentrations CuS thin film deposited on ITO had the lowest resistivity. This leads to the result that the conductivity was high for CuS thin film deposited on ITO substrate, and the conductivity of the three thin films of 0.2 M concentration was higher than that of 0.4 M concentration.

[Inhibition of Low Molecular Organic Acids on the Activity of Acidithiobacillus Species and Its Effect on the Removal of Heavy Metals from Contaminated Soil].

Science.gov (United States)

Song, Yong-wei; Wang, He-rul; Cao, Yan-xiao; Li, Fei; Cui, Chun-hong; Zhou, Li

2016-05-15

Application of organic fertilizer can reduce the solubility and bioavailability of heavy metals in contaminated soil, but in the flooded anaerobic environment, organic fertilizer will be decomposed to produce a large number of low molecular organic acids, which can inhibit the biological activity of Acidithiobacillus species. Batch cultures studies showed that the monocarboxylic organic acids including formic acid, acetic acid, propionic acid, and butyric acid exhibited a marked toxicity to Acidithiobacillus species, as indicated by that 90% of inhibitory rate for Fe2 and So oxidation in 72 h were achieved at extremely low concentrations of 41.2 mg · L⁻¹, 78.3 mg · L⁻¹, 43.2 mg · L⁻¹, 123.4 mg · L⁻¹ and 81.9 mg 230. 4 mg · L⁻¹, 170.1 mg · L⁻¹, 123.4 mg · L⁻¹ respectively. Of these organic acids, formic acid was the most toxic one as indicated by that Fe2 and So oxidation was almost entirely inhibited at a low concentration. In addition, it was found that Acidithiobacillus ferrooxidans was more sensitive to low molecular organic acids than Acidithiobacillus thiooxidans. What's more, there was little effect on biological acidification process of heavy metal contaminated soil when organic acids were added at initial stage (Oh), but it was completely inhibited when these acids were added after 12 h of conventional biological acidification, thus decreasing the efficiency of heavy metals dissolution from soil.

Low-temperature solid-state preparation of ternary CdS/g-C_3N_4/CuS nanocomposites for enhanced visible-light photocatalytic H_2-production activity

International Nuclear Information System (INIS)

Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

2017-01-01

Highlights: • CdS/g-C_3N_4/CuS composite were synthesized by low-temperature solid-state method. • CdS/g-C_3N_4/CuS show enhanced visible-light photocatalytic H_2 evolution activity. • The enhanced photocatalytic H_2 production activity is due to the heterojunction. • Heterojunction between the components promote charge separation/transfer property. - Abstract: Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C_3N_4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C_3N_4/CuS composite exhibits a high visible-light photocatalytic H_2-production rate of 57.56 μmol h"−"1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na_2S/Na_2SO_3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C_3N_4/CuS composites show the enhanced visible-light photocatalytic H_2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C_3N_4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H_2-production activity.

H3PO4 treated surface modified CuS counter electrodes with high electrocatalytic activity for enhancing photovoltaic performance of quantum dot-sensitized solar cells

Science.gov (United States)

Panthakkal Abdul Muthalif, Mohammed; Sunesh, Chozhidakath Damodharan; Choe, Youngson

2018-05-01

Herein we report a simple synthetic strategy to prepare highly efficient and surface modified CuS counter electrodes (CEs) for quantum dot-sensitized solar cells (QDSSCs) in the presence of phosphoric acid (H3PO4) using the chemical bath deposition method. This is the first report of successful treatment of H3PO4 on the surface of CuS CEs for designing a high-performance QDSSCs with improved photovoltaic properties. After optimization, the 4 ml H3PO4 treated CuS CE-based QDSSC exhibits excellent photovoltaic performance with a conversion efficiency (η) of 4.20% (Voc = 0.592 V, Jsc = 13.35 mA cm-2, FF = 0.532) under one full-sun illumination (100 mW cm-2, AM 1.5 G).

Bioleaching of heavy metals from sewage sludge using Acidithiobacillus thiooxidans

Science.gov (United States)

Wen, Ye-Ming; Lin, Hong-Yan; Wang, Qing-Ping; Chen, Zu-Liang

2010-11-01

Acidithiobacillus thiooxidans was isolated from sewage sludge using the incubation in the Waksman liquor medium and the inoculation in Waksman solid plate. It was found that the optimum conditions of the bioleaching included solid concentration 2%, sulfur concentration 5 gṡL-1 and cell concentration 10%. The removal efficiency of Cr, Cu, Pb and Zh in sewage sludge, which was obtained from waste treatment plant, Jinshan, Fuzhou, was 43.65%, 96.24%, 41.61% and 96.50% in the period of 4˜10 days under the optimum conditions, respectively. After processing using the proposed techniques, the heavy metals in sewage sludge did meet the requirement the standards of nation.

Potentiality of Acidithiobacillus thiooxidans in Microbial Solubilization of Phosphate Mine Tailings

Directory of Open Access Journals (Sweden)

S Dhakar

2015-04-01

Full Text Available This paper deals with the solubilization behavior of the tailings produced by the floatation of a complex low grade phosphate ore. The composition of the tailings was essentially dolomite (52.04% with minor amounts of phosphate, iron and aluminium oxides (10.4 and 0.5% respectively. The presence of these products created uncontrolled land pollution and severely affected groundwater. An initiative has been taken up for utilization of this waste to generate an eco-friendly product. First step towards this panorama is incorporation of suitable microorganisms for the biodegradation of this effluent. Sulphur oxidizing bacteria Acidithiobacillus thiooxidans produces sulphuric acid which neutralizes the dolomitic tailings and convert it into plant available forms. The solubilization activity was tested in sulphur medium with 5, 10, 15 and 20% concentration of tailings. The solubilization is graded on the basis of pH, Electrical conductivity (EC, soluble calcium and magnesium and soluble phosphate. The results from ex-situ experiments showed that the treatment with 15% tailings ended with highest solubilization. The values of pH, EC, soluble calcium and magnesium and soluble phosphate for this treatment were 4.92, 31.6 dS/m, 10.8 mL EDTA and 17.24 µg/mL respectively. Also, the results proved that sulphur oxidizing bacteria Acidithiobacillus thiooxidans is capable of solubilizing dolomitic tailings from the Jhamarkotra mines. Finally, an important factor taken into account was solubilization of residual phosphate along with dolomite in the tailings. This combined action affects the solubilization behaviour of the residue, which was also showed successfully with the assayed laboratory studies.

CuInS{sub 2} thin films obtained through the annealing of chemically deposited In{sub 2}S{sub 3}-CuS thin films

Energy Technology Data Exchange (ETDEWEB)

Pena, Y., E-mail: yolapm@gmail.com [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Pedro de Alba S/N, Ciudad Universitaria, 66451, San Nicolas de los Garza, Nuevo Leon (Mexico); Lugo, S. [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Pedro de Alba S/N, Ciudad Universitaria, 66451, San Nicolas de los Garza, Nuevo Leon (Mexico); Calixto-Rodriguez, M. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Privada Xochicalco S/N, Col Centro, 62580, Temixco, Morelos (Mexico); Vazquez, A.; Gomez, I.; Elizondo, P. [Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Pedro de Alba S/N, Ciudad Universitaria, 66451, San Nicolas de los Garza, Nuevo Leon (Mexico)

2011-01-01

In this work, we report the formation of CuInS{sub 2} thin films on glass substrates by heating chemically deposited multilayers of copper sulfide (CuS) and indium sulfide (In{sub 2}S{sub 3}) at 300 and 350 deg. C in nitrogen atmosphere at 10 Torr. CIS thin films were prepared by varying the CuS layer thickness in the multilayers with indium sulfide. The XRD analysis showed that the crystallographic structure of the CuInS{sub 2} (JCPDS 27-0159) is present on the deposited films. From the optical analysis it was estimated the band gap value for the CIS film (1.49 eV). The electrical conductivity varies from 3 x 10{sup -8} to 3 {Omega}{sup -1} cm{sup -1} depending on the thickness of the CuS film. CIS films showed p-type conductivity.

Bacterial CS2 Hydrolases from Acidithiobacillus thiooxidans Strains Are Homologous to the Archaeal Catenane CS2 Hydrolase

NARCIS (Netherlands)

Smeulders, M.J.; Pol, A. van der; Venselaar, H.; Barends, T.R.; Hermans, J.; Jetten, M.S.M.; Camp, H.J.M. op den

2013-01-01

Carbon disulfide (CS2) and carbonyl sulfide (COS) are important in the global sulfur cycle, and CS2 is used as a solvent in the viscose industry. These compounds can be converted by sulfur-oxidizing bacteria, such as Acidithiobacillus thiooxidans species, to carbon dioxide (CO2) and hydrogen sulfide

Acidithiobacillus thiooxidans secretome containing a newly described lipoprotein Licanantase enhances chalcopyrite bioleaching rate

Science.gov (United States)

Bobadilla Fazzini, Roberto A.; Levican, Gloria

2010-01-01

The nature of the mineral–bacteria interphase where electron and mass transfer processes occur is a key element of the bioleaching processes of sulfide minerals. This interphase is composed of proteins, metabolites, and other compounds embedded in extracellular polymeric substances mainly consisting of sugars and lipids (Gehrke et al., Appl Environ Microbiol 64(7):2743–2747, 1998). On this respect, despite Acidithiobacilli—a ubiquitous bacterial genera in bioleaching processes (Rawlings, Microb Cell Fact 4(1):13, 2005)—has long been recognized as secreting bacteria (Jones and Starkey, J Bacteriol 82:788–789, 1961; Schaeffer and Umbreit, J Bacteriol 85:492–493, 1963), few studies have been carried out in order to clarify the nature and the role of the secreted protein component: the secretome. This work characterizes for the first time the sulfur (meta)secretome of Acidithiobacillus thiooxidans strain DSM 17318 in pure and mixed cultures with Acidithiobacillus ferrooxidans DSM 16786, identifying the major component of these secreted fractions as a single lipoprotein named here as Licanantase. Bioleaching assays with the addition of Licanantase-enriched concentrated secretome fractions show that this newly found lipoprotein as an active protein additive exerts an increasing effect on chalcopyrite bioleaching rate. Electronic supplementary material The online version of this article (doi:10.1007/s00253-010-3063-8) contains supplementary material, which is available to authorized users. PMID:21191788

CuS nanoplates from ionic liquid precursors—Application in organic photovoltaic cells

Science.gov (United States)

Kim, Yohan; Heyne, Benjamin; Abouserie, Ahed; Pries, Christopher; Ippen, Christian; Günter, Christina; Taubert, Andreas; Wedel, Armin

2018-05-01

Hexagonal p-type semiconductor CuS nanoplates were synthesized via a hot injection method from bis(trimethylsilyl)sulfide and the ionic liquid precursor bis(N-dodecylpyridinium) tetrachloridocuprate(ii). The particles have a broad size distribution with diameters between 30 and 680 nm and well-developed crystal habits. The nanoplates were successfully incorporated into organic photovoltaic (OPV) cells as hole conduction materials. The power conversion efficiency of OPV cells fabricated with the nanoplates is 16% higher than that of a control device fabricated without the nanoplates.

Low-temperature solid-state preparation of ternary CdS/g-C3N4/CuS nanocomposites for enhanced visible-light photocatalytic H2-production activity

Science.gov (United States)

Cheng, Feiyue; Yin, Hui; Xiang, Quanjun

2017-01-01

Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C3N4/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C3N4/CuS composite exhibits a high visible-light photocatalytic H2-production rate of 57.56 μmol h-1 with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na2S/Na2SO3 mixed aqueous solution as sacrificial agent. The ternary CdS/g-C3N4/CuS composites show the enhanced visible-light photocatalytic H2-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C3N4 in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H2-production activity.

EXAFS investigation of uranium(6) complexes formed at Acidithiobacillus ferro oxidans types

International Nuclear Information System (INIS)

Merroun, M.; Reich, T.; Hennig, Ch.; Selenska-Pobell, S.

2002-01-01

Mining activities have brought excessive amounts of uranium into the environment. In uranium deposits a number of acidophilic chemo-litho-autotrophic bacteria have been identified which are able to oxidize sulphide minerals, elemental sulphur, ferrous iron and also (in the presence of uranium mineral) U(IV). In particular, the interaction of one representative of the group Acidithiobacillus ferro oxidans (new designation of Thiobacillus ferro oxidans) with uranium has been investigated. Uranium(VI) complex formations at the surfaces of Acidithiobacillus ferro oxidans were studied using uranium L III -edge extended X-ray absorption fine structure (EXAFS) spectroscopy. In all samples uranium is co-ordinated by two axial oxygen atoms (O ax ) at a distance of 1.77-1.78 angstrom. The average distance between uranium and the equatorial oxygen atoms (O eq ) is 2.35 angstrom. The co-ordination number for O eq is 5-6. In comparison to the uranium crystal structure data, the U-O eq distance indicates a co-ordination number of the equatorial oxygen of 5. Within the experimental error, there are no differences in the U-O bond distances between samples from the three types of A. ferro oxidans investigated. The fit to the EXAFS data of samples measured as wet pastes gave the same results as for dried samples. No significant structural differences were observed for the uranium complexes formed by the eco-types of A. ferro oxidans. However, the EXAFS spectra do indicate a formation of uranium complexes which are different from those formed by Bacilli where the bond length of 2.28 angstrom indicates a co-ordination number of 4 for the equatorial oxygen atoms. (authors)

Low-temperature solid-state preparation of ternary CdS/g-C{sub 3}N{sub 4}/CuS nanocomposites for enhanced visible-light photocatalytic H{sub 2}-production activity

Energy Technology Data Exchange (ETDEWEB)

Cheng, Feiyue; Yin, Hui; Xiang, Quanjun, E-mail: xiangqj@mail.hzau.edu.cn

2017-01-01

Highlights: • CdS/g-C{sub 3}N{sub 4}/CuS composite were synthesized by low-temperature solid-state method. • CdS/g-C{sub 3}N{sub 4}/CuS show enhanced visible-light photocatalytic H{sub 2} evolution activity. • The enhanced photocatalytic H{sub 2} production activity is due to the heterojunction. • Heterojunction between the components promote charge separation/transfer property. - Abstract: Low-temperature solid-state method were gradually demonstrated as a high efficiency, energy saving and environmental protection strategy to fabricate composite semiconductor materials. CdS-based multiple composite photocatalytic materials have attracted increasing concern owning to the heterostructure constituents with tunable band gaps. In this study, the ternary CdS/g-C{sub 3}N{sub 4}/CuS composite photocatalysts were prepared by a facile and novel low-temperature solid-state strategy. The optimal ternary CdS/g-C{sub 3}N{sub 4}/CuS composite exhibits a high visible-light photocatalytic H{sub 2}-production rate of 57.56 μmol h{sup −1} with the corresponding apparent quantum efficiency reaches 16.5% at 420 nm with Na{sub 2}S/Na{sub 2}SO{sub 3} mixed aqueous solution as sacrificial agent. The ternary CdS/g-C{sub 3}N{sub 4}/CuS composites show the enhanced visible-light photocatalytic H{sub 2}-evolution activity comparing with the binary CdS-based composites or simplex CdS. The enhanced photocatalytic activity is ascribed to the heterojunctions and the synergistic effect of CuS and g-C{sub 3}N{sub 4} in promotion of the charge separation and charge mobility. This work shows that the low-temperature solid-state method is efficient and environmentally benign for the preparation of CdS-based multiple composite photocatalytic materials with enhanced visible-light photocatalytic H{sub 2}-production activity.

Formation of jarosite during Fe{sup 2+} oxidation by Acidithiobacillus ferrooxidans

Energy Technology Data Exchange (ETDEWEB)

Daoud, J.; Karamanev, D. [University of Western Ontario, London, ON (Canada). Dept. of Chemical & Biochemical Engineering

2006-07-15

Jarosite precipitation is a very important phenomenon that is observed in many bacterial cultures. In many applications involving Acidithiobacillus ferrooxidans, like coal desulphurization and bioleaching, it is crucial to minimize jarosite formation in order to increase efficiency. The formation of jarosite during the oxidation of ferrous iron by free suspended cells of A. ferrooxidans was studied. The process was studied as a function of time, pH and temperature. The main parameter affecting the jarosite formation was pH. Several experiments yielded results showing oxidation rates as high as 0.181-0.194 g/L h, with low jarosite precipitation of 0.0125-0.0209 g at conditions of pH 1.6-1.7 with an operating temperature of 35{sup o} C.

Characterization of CuS nanocrystalline thin films synthesized by chemical bath deposition and dip coating techniques

International Nuclear Information System (INIS)

Chaki, Sunil H.; Deshpande, M.P.; Tailor, Jiten P.

2014-01-01

CuS thin films were synthesized by chemical bath deposition and dip coating techniques at ambient temperature. The energy dispersive analysis of X-rays of the thin films confirmed that both the as synthesized thin films are stoichiometric. The X-ray diffraction of the chemical bath deposited and dip coating deposited thin films showed that the films possess hexagonal structure having lattice parameters, a = b = 3.79 A and c = 16.34 A. The crystallite sizes determined from the X-ray diffraction data using Scherrer's formula for the chemical bath deposition and dip coating deposition thin films came out to be nearly 11 nm and 13 nm, respectively. The optical microscopy of the as deposited thin films surfaces showed that the substrates are well covered in both the deposited films. The scanning electron microscopy of the thin films clearly showed that in chemical bath deposited thin films the grain size varies from few μm to nm, while in dip coating deposited films the grain size ranges in nm. The optical bandgap determined from the optical absorbance spectrum analysis showed, chemical bath deposited thin films possess direct bandgap of 2.2 eV and indirect bandgap of 1.8 eV. In the case of dip coating deposited thin films, the direct bandgap is 2.5 eV and indirect bandgap is 1.9 eV. The d.c. electrical resistivity variation with temperature for both the deposited films showed that the resistivity decreases with temperature thus confirming the semiconducting nature. The thermoelectric power variations with temperature and the room temperature Hall Effect study of both the synthesized CuS thin films showed them to be of p-type conductivity. The obtained results are discussed in details. - Highlights: • CuS thin films were synthesized by chemical bath deposition and dip coating techniques. • The films possessed hexagonal structure. • The optical absorption showed that the films had direct and indirect bandgap. • Study of electrical transport properties

Hydrogen sulfide removal from air by Acidithiobacillus thiooxidans in a trickle bed reactor.

Science.gov (United States)

Ramirez, M; Gómez, J M; Cantero, D; Páca, J; Halecký, M; Kozliak, E I; Sobotka, M

2009-09-01

A strain of Acidithiobacillus thiooxidans immobilized in polyurethane foam was utilized for H(2)S removal in a bench-scale trickle-bed reactor, testing the limits of acidity and SO(4) (2-) accumulation. The use of this acidophilic strain resulted in remarkable stability in the performance of the system. The reactor maintained a >98-99 % H(2)S removal efficiency for c of up to 66 ppmv and empty bed residence time 98 % H(2)S was achieved under steady-state conditions, over the pH range of 0.44-7.30. Despite the accumulation of acidity and SO(4) (2-) (up to 97 g/L), the system operated without inhibition.

Evaluation the effect of uranium ore concentrations on the cyc2 gene expression in the mutated Acidithiobacillus sp. FJ2

Directory of Open Access Journals (Sweden)

Faezeh Fatemi

2018-06-01

Full Text Available Introduction: The uranium bioleaching process is performed using Acidithiobacillus ferrooxidans. This bacterium is capable of iron oxidation by an electron transport chain. One of the most important components of this chain is the cyc2 gene product that involved in the oxidation process of iron. Materials and methods: Evaluation of UV mutated (60, 120 and 180s Acidithiobacillus sp. FJ2 cyc2gene in the presence of uranium ore concentrations, has been implemented in this project. For this purpose, the original and mutated bacteria were cultivated in the presence of uranium ore concentrations (5, 10, 15, 25 and 50%. Uranium extraction, variation of pH and Eh values were measured at 24 h intervals. Then, when the uranium extraction yield reached to 100%, gene expressions of cyc2 original and mutatedAcidithiobacillus sp. FJ2 were analyzed using Real-time PCR method. Results: The results of the experiments showed that, with increasing pulp density, the uranium extraction rate and oxidation activity of bacteria were reduced. In addition, the result of cyc2 gene expression showed that the target gene expression increases in the presence of uranium ore compared to sample with absence of uranium ore, andwith further increase of pulp density, due to the toxicity of uranium, shows a decreasing trend. Discussion and conclusion: The results of this study indicated that the mutation in the bacterium has a positive effect on the uranium bioleaching process, which can play an important role in the process of uranium bioleaching at high concentrations. In addition, with increasing pulp density due to uranium toxicity, there is a decreasing trend in the process of uranium extraction, which indicates the important role of this factor in the uranium bioleaching process.

Evaluating Acidithiobacillus ferrooxidans bacterial oxidation of sulphur compounds using FTIR and X-ray diffraction assays

Directory of Open Access Journals (Sweden)

Alexandra Muñoz

2003-01-01

Full Text Available A native bacterial strain capable of oxidising ferrous iron and sulphur compounds was isolated from effluent and material from the La Maruja gold mine in the municipality of Marmato (Caldas; this was biochemically identified as being Acidithiobacillus ferrooxidans. This strain's ability to oxidise metallic sulphide concentrates having two differ-ent pulp proportions and two particle sizes was evaluated. Sulphide bio-oxidation was observed after 15 days showing this strain's catalytic action on the mineral break-down process. Key words: bio-oxidation; bio-leaching; A. ferrooxidans; sulphides

Amenability of low-grade uranium towards column bioleaching by acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Abhilash; Mehta, K.D.; Kumar, V.; Pandey, B.D.; Tamrakar, P.K.

2007-01-01

R and D studies were carried out at NML using Acidithiobacillus ferrooxidans (Ac.Tf) in column for the bio-recovery of uranium from the low-grade uranium ore containing 0.024% U 3 O 8 of Turamdih mines, Singhbhum. A recovery of 55.48% uranium was obtained in bio-leaching as against ∼ 44.9% in sterile control in 30 days at 1.7 pH in a column containing 2.5kg ore of particle size mainly in the range 5-1mm. In the large scale column, leaching with 80kg ore of particle size ∼ 0.5cm, uranium bio-recovery was found to be 69.8% in comparison to a recovery of 55% in control set at 1.7 pH in 50 days. The uranium recoveries followed indirect leaching mechanism. (author)

Properties of CuS thin films treated in air plasma

International Nuclear Information System (INIS)

Rodriguez-Lazcano, Y.; Martinez, H.; Calixto-Rodriguez, M.; Nunez Rodriguez, A.

2009-01-01

Copper sulfide thin films were grown by chemical deposition and post treated in air plasma during 20 min. Air plasma was generated by alternating current discharge at a pressure of 4 x 10 2 Pa. The power discharge was maintained at an output of 220 V and a current of 0.2 A. Thermal annealing at 300 o C was performed for comparison. X-ray diffraction shows that plasma treatment results in phase transformation of Cu 39 S 28 (as grown) to CuS (treated by plasma). The copper lost is confirmed by X-ray fluorescence. No significant change in the optical band gap was observed due to plasma action. In addition, the electrical conductivity increases in one order of magnitude. On the other hand, the samples under plasma condition show a parallel growth to the substrate and an increase in the surface uniformity. The plasma etching removes copper due to its affinity with oxygen to form CuO, as is corroborated by optical emission spectroscopy.

Aplicação de técnicas eletroquímicas no estudo da dissolução oxidativa da covelita (CuS por Thiobacillus ferrooxidans Electrochemical techniques applied to study the oxidative dissolution of the covellite: CuS by Thiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

Christiane Medina Teixeira

2002-02-01

Full Text Available Among the copper sulphides, chalcopyrite (CuFeS2, covellite (CuS and chalcocite (Cu2S are the most important source of minerals for copper mining industry. The acknowledge of behaviour of these sulphides related with bacterial leaching process are essential for optimization procedures. Despite of its importance, covellite has not deserved much interest of researchers regarding this matter. In this work it was studied the oxidation of covellite by the chemolithotrophic bacterium Thiobacillus ferrooxidans by using electrochemical techniques, such as open circuit potentials with the time and cyclic voltammetry. The experiments were carried out in acid medium (pH 1.8, containing or not Fe2+ as additional energy source, and in different periods of incubation; chemical controls were run in parallel. The results showed that a sulphur layer is formed spontaneously due the acid attack, covering the sulphide in the initial phase of incubation, blocking the sulphide oxidation. However, the bacterium was capable to oxidize this sulphur layer. In the presence of Fe2+ as supplemental energy source, the corrosion process was facilitated, because ocurred an indirect oxidation of covellite by Fe3+, which was produced by T. ferrooxidans oxidation of the Fe2+ added in the medium.

Visualization of Protease Activity In Vivo Using an Activatable Photo-Acoustic Imaging Probe Based on CuS Nanoparticles

Science.gov (United States)

Yang, Kai; Zhu, Lei; Nie, Liming; Sun, Xiaolian; Cheng, Liang; Wu, Chenxi; Niu, Gang; Chen, Xiaoyuan; Liu, Zhuang

2014-01-01

Herein, we for the first time report a novel activatable photoacoustic (PA) imaging nano-probe for in vivo detection of cancer-related matrix metalloproteinases (MMPs). A black hole quencher 3 (BHQ3) which absorbs red light is conjugated to near-infrared (NIR)-absorbing copper sulfide (CuS) nanoparticles via a MMP-cleavable peptide linker. The obtained CuS-peptide-BHQ3 (CPQ) nano-probe exhibits two distinctive absorption peaks at 630 nm and 930 nm. Inside the tumor microenviorment where MMPs present, the MMP-sensitive peptide would be cleaved, releasing BHQ3 from the CuS nanoparticles, the former of which as a small molecule is then rapidly cleared out from the tumor, whereas the latter of which as large nanoparticles would retain inside the tumor for a much longer period of time. As the result, the PA signal at 680 nm which is contributed by BHQ3 would be quickly diminished while that at 930 nm would be largely retained. The PA signal ratio of 680 nm / 930 nm could thus serve as an in vivo indicator of MMPs activity inside the tumor. Our work presents a novel strategy of in vivo sensing of MMPs based on PA imaging, which should offer remarkably improved detection depth compared with traditional optical imaging techniques. PMID:24465271

Global transcriptional responses of Acidithiobacillus ferrooxidans Wenelen under different sulfide minerals.

Science.gov (United States)

Latorre, Mauricio; Ehrenfeld, Nicole; Cortés, María Paz; Travisany, Dante; Budinich, Marko; Aravena, Andrés; González, Mauricio; Bobadilla-Fazzini, Roberto A; Parada, Pilar; Maass, Alejandro

2016-01-01

In order to provide new information about the adaptation of Acidithiobacillus ferrooxidans during the bioleaching process, the current analysis presents the first report of the global transcriptional response of the native copper mine strain Wenelen (DSM 16786) oxidized under different sulfide minerals. Microarrays were used to measure the response of At. ferrooxidans Wenelen to shifts from iron supplemented liquid cultures (reference state) to the addition of solid substrates enriched in pyrite or chalcopyrite. Genes encoding for energy metabolism showed a similar transcriptional profile for the two sulfide minerals. Interestingly, four operons related to sulfur metabolism were over-expressed during growth on a reduced sulfur source. Genes associated with metal tolerance (RND and ATPases type P) were up-regulated in the presence of pyrite or chalcopyrite. These results suggest that At. ferrooxidans Wenelen presents an efficient transcriptional system developed to respond to environmental conditions, namely the ability to withstand high copper concentrations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bioleaching of two different types of chalcopyrite by Acidithiobacillus ferrooxidans

Science.gov (United States)

Dong, Ying-bo; Lin, Hai; Fu, Kai-bin; Xu, Xiao-fang; Zhou, Shan-shan

2013-02-01

Two different types of chalcopyrite (pyritic chalcopyrite and porphyry chalcopyrite) were bioleached with Acidithiobacillus ferrooxidans ATF6. The bioleaching of the pyritic chalcopyrite and porphyry chalcopyrite is quite different. The copper extraction reaches 46.96% for the pyritic chalcopyrite after 48-d leaching, but it is only 14.50% for the porphyry chalcopyrite. Proper amounts of initial ferrous ions can improve the efficiency of copper extraction for the two different types of chalcopyrite. The optimum dosage of ferrous ions for the pyritic chalcopyrite and porphyry chalcopyrite is different. The adsorption of ATF6 on the pyritic chalcopyrite and porphyry chalcopyrite was also studied in this paper. It is found that ATF6 is selectively adsorbed by the two different types of chalcopyrite; the higher adsorption onto the pyritic chalcopyrite than the porphyry chalcopyrite leads to the higher copper dissolution rate of the pyritic chalcopyrite. In addition, the zeta-potential of chalcopyrite before and after bioleaching further confirms that ATF6 is more easily adsorbed onto the pyritic chalcopyrite.

Synergy between Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the Bioleaching Process of Copper

Directory of Open Access Journals (Sweden)

Xuecheng Zheng

2016-01-01

Full Text Available This study investigates the synergy of Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the bioleaching process of copper. The results showed that additional R. phaseoli could increase leaching rate and cell number of A. ferrooxidans. When the initial cell number ratio between A. ferrooxidans and R. phaseoli was 2 : 1, A. ferrooxidans attained the highest final cell number of approximately 2 × 108 cells/mL and the highest copper leaching rate of 29%, which is 7% higher than that in the group with A. ferrooxidans only. R. phaseoli may use metabolized polysaccharides from A. ferrooxidans, and organic acids could chelate or precipitate harmful heavy metals to reduce their damage on A. ferrooxidans and promote its growth. Organic acids could also damage the mineral lattice to increase the leaching effect.

Synergy between Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the Bioleaching Process of Copper

Science.gov (United States)

Zheng, Xuecheng; Li, Dongwei

2016-01-01

This study investigates the synergy of Rhizobium phaseoli and Acidithiobacillus ferrooxidans in the bioleaching process of copper. The results showed that additional R. phaseoli could increase leaching rate and cell number of A. ferrooxidans. When the initial cell number ratio between A. ferrooxidans and R. phaseoli was 2 : 1, A. ferrooxidans attained the highest final cell number of approximately 2 × 108 cells/mL and the highest copper leaching rate of 29%, which is 7% higher than that in the group with A. ferrooxidans only. R. phaseoli may use metabolized polysaccharides from A. ferrooxidans, and organic acids could chelate or precipitate harmful heavy metals to reduce their damage on A. ferrooxidans and promote its growth. Organic acids could also damage the mineral lattice to increase the leaching effect. PMID:26942203

Selective separation of arsenopyrite from pyrite by biomodulation in the presence of Acidithiobacillus ferrooxidans.

Science.gov (United States)

Chandraprabha, M N; Natarajan, K A; Somasundaran, P

2004-08-15

Effective methods for selective separation using flotation or flocculation of arsenopyrite from pyrite by biomodulation using Acidithiobacillus ferrooxidans are presented here. Adhesion of the bacterium to the surface of arsenopyrite was very slow compared to that to pyrite, resulting in a difference in surface modification of the minerals subsequent to interaction with cells. The cells were able to effectively depress pyrite flotation in presence of collectors like potassium isopropyl xanthate and potassium amyl xanthate. On the other hand the flotability of arsenopyrite after conditioning with the cells was not significantly affected. The activation of pyrite by copper sulfate was reduced when the minerals were conditioned together, resulting in better selectivity. Selective separation could also be achieved by flocculation of biomodulated samples.

The CdS/CdSe/ZnS Photoanode Cosensitized Solar Cells Basedon Pt, CuS, Cu2S, and PbS Counter Electrodes

Directory of Open Access Journals (Sweden)

Tung Ha Thanh

2014-01-01

Full Text Available Highly ordered mesoporous TiO2 modified by CdS, CdSe, and ZnS quantum dots (QDs was fabricated by successive ionic layer adsorption and reaction (SILAR method. The quantity of material deposition seems to be affected not only by the employed deposition method but also and mainly by the nature of the underlying layer. The CdS, CdSe, and ZnS QDs modification expands the photoresponse range of mesoporous TiO2 from ultraviolet region to visible range, as confirmed by UV-Vis spectrum. Optimized anode electrodes led to solar cells producing high current densities. Pt, CuS, PbS, and Cu2S have been used as electrocatalysts on counter electrodes. The maximum solar conversion efficiency reached in this work was 1.52% and was obtained by using Pt electrocatalyst. CuS, PbS, and Cu2S gave high currents and this was in line with the low charge transfer resistances recorded in their case.

Preliminary X-ray crystallographic analysis of sulfide:quinone oxidoreductase from Acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Zhang, Yanfei; Cherney, Maia M.; Solomonson, Matthew; Liu, Jianshe; James, Michael N. G.; Weiner, Joel H.

2009-01-01

The sulfide:quinone oxidoreductase from A. ferrooxidans ATCC 23270 was overexpressed in E. coli and purified. Crystallization and preliminarily X-ray crystallographic analysis were performed for the recombinant enzyme. The gene product of open reading frame AFE-1293 from Acidithiobacillus ferrooxidans ATCC 23270 is annotated as encoding a sulfide:quinone oxidoreductase, an enzyme that catalyses electron transfer from sulfide to quinone. Following overexpression in Escherichia coli, the enzyme was purified and crystallized using the hanging-drop vapour-diffusion method. The native crystals belonged to the tetragonal space group P4 2 2 1 2, with unit-cell parameters a = b = 131.7, c = 208.8 Å, and diffracted to 2.3 Å resolution. Preliminary crystallographic analysis indicated the presence of a dimer in the asymmetric unit, with an extreme value of the Matthews coefficient (V M ) of 4.53 Å 3 Da −1 and a solvent content of 72.9%

Biocompatibility evaluation of magnetosomes formed by Acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Yan Lei; Yue Xiaoxuan; Zhang Shuang; Chen Peng; Xu Zhiliang; Li Yang; Li Hongyu

2012-01-01

Magnetite nanocrystal has been extensively used in biomedical field. Currently, an interesting alternative to synthetic magnetic Fe 3 O 4 nanoparticles, called magnetosome, has been found in magnetotactic bacteria. It has been reported that Acidithiobacillus ferrooxidans (At. ferrooxidans) has a potential to synthesize magnetosome. In this study, transmission electron microscope (TEM) was used to analyze the magnetite particles in At. ferrooxidans BY-3. The magnetosomes formed by this bacterium were isolated by a method combining ultracentrifugation and magnetic separation. Crystalline phase and surface functional group of the magnetosomes were investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), respectively. Biocompatibility of the magnetosomes was systematically evaluated at various concentrations (0.5, 1.0, 2.0 and 4.0 mg/ml). MTT test, hemolysis assay and Micronucleus Test were carried out to evaluate in vitro cytotoxicity, blood toxicity and genotoxicity of magnetosomes, respectively. Under these conditions, magnetosomes showed no cytotoxic, genotoxic and hemolytic effects up to 4.0 mg/ml indicating good biocompatibility of these biological nanoparticles. These revealed that the magnetosomes might have a potential for biotechnological and biomedical applications in the future. - Highlights: ► The production of magnetosomes from At. ferrooxidans has been easily available. ► Several techniques are used to characterize properties of the magnetosomes. ► The magnetosomes have no cytotoxicity, no hemolysis activity and no genotoxicity.

A catharsis in the mirror: Lobo Antunes’s Os cus de Judas

Directory of Open Access Journals (Sweden)

Neiva Kampff Garcia

2014-08-01

Full Text Available The 1979 novel Os cus de Judas by António Lobo Antunes, is part of a trilogy with Memória de elefante ([1979] 2009 and Conhecimento do inferno ([1980] 2006, which he calls ‘the learning cycle’. It demystifies, in fiction, the official reports on the colonial war in an autobiographical elaboration. Dealing with the African colonial war, contemporary Portuguese society, alienation about the African events and the omissive silence among the upper classes, the narrative of a comeback is revealed by auto-reflexive reminiscence. The process, conducted by the Antonian narrator, constitutes a catharsis in front of the mirror, whose protagonist is a psychiatrist who speaks about, in and for himself from his childhood to the present. An overwhelming and vigorous writing introduces a new perspective into Portuguese literature in the historical period of post-25th April, dealt with in current article.

Synergistic bioleaching of chalcopyrite and bornite in the presence of Acidithiobacillus ferrooxidans.

Science.gov (United States)

Zhao, Hongbo; Wang, Jun; Hu, Minghao; Qin, Wenqing; Zhang, Yansheng; Qiu, Guanzhou

2013-12-01

Bioleaching of chalcopyrite and bornite in the presence of Acidithiobacillus ferrooxidans was carried out to investigate the influences between each other during bioleaching. Bioleaching results indicated that bornite accelerated the dissolution of chalcopyrite, and chalcopyrite also accelerated the dissolution of bornite, it could be described as a synergistic effect during bioleaching, this synergistic effect might be attributed to the galvanic effect between chalcopyrite and bornite, and to the relatively low solution potential as the addition of bornite. Significantly amount of elemental sulfur and jarosite formed on the minerals surface might be the main passivation film inhibiting the further dissolution, and the amount of elemental sulfur significantly increased with the addition of bornite. Results of electrochemical measurements indicated that the oxidation and reduction mechanisms of chalcopyrite and bornite were similar, the addition of bornite or chalcopyrite did not change the oxidative and reductive mechanisms, but increased the oxidation rate. Copyright © 2013 Elsevier Ltd. All rights reserved.

Vanadium Bioleaching Behavior by Acidithiobacillus ferrooxidans from a Vanadium-Bearing Shale

Directory of Open Access Journals (Sweden)

Dunpei Wei

2018-01-01

Full Text Available This study investigated bioleaching behavior of vanadium from a vanadium-bearing shale using Acidithiobacillus ferrooxidans (A. ferrooxidans. Results showed a maximum recovery of 62% vanadium in 1.2-day bioleaching, which was 22.45% higher than the controls. Then, the vanadium leaching efficiency decreased significantly, only 24% of that was obtained on the tenth day. The vanadium extraction in 1.2 days was mainly attributed to the dissolution of vanadium in free oxides of shale. Fe3+ produced by A. ferrooxidans promoted the dissolution process. X-ray diffraction (XRD patterns of the leached residues confirmed the generation of jarosite. SEM-EDS analysis of the residues indicated that jarosite adsorbed on the shale and inhibited the further dissolution of vanadium. The relevance of V, Fe, S, O was quite good in the energy disperse X-ray spectrometry (EDS element mapping of jarosite, and acid-washing of the jarosite resulted in 31.6% of the vanadium in the precipitates desorption, indicating that the decrease of vanadium leaching efficiency in bioleaching process was caused by both adsorption and co-precipitation with jarosite.

Effect of pH values on the extracellular polysaccharide secreted by Acidithiobacillus ferrooxidans during chalcopyrite bioleaching

Science.gov (United States)

Yu, Run-lan; Liu, Jing; Tan, Jian-xi; Zeng, Wei-min; Shi, Li-juan; Gu, Guo-hua; Qin, Wen-qing; Qiu, Guan-zhou

2014-04-01

The pH value plays an important role in the bioleaching of sulphide minerals. The effect of pH values on the extracellular polysaccharide secreted by Acidithiobacillus ferrooxidans was investigated in different phases of bacterial growth during chalcopyrite bioleaching. It is found that extracellular polysaccharide secretion from the cells attached to chalcopyrite is more efficiently than that of the free cells in the bioleaching solution. Three factors, pH values, the concentration of soluble metal ions, and the bacterial growth and metabolism, affect extracellular polysaccharide secretion in the free cells, and are related to the bacterial growth phase. Extracellular polysaccharide secretion from the attached cells is mainly dependent on the pH value of the bacterial culture.

Facile and low temperature route to synthesis of CuS nanostructure in mesoporous material by solvothermal method.

Science.gov (United States)

Sohrabnezhad, Sh; Zanjanchi, M A; Hosseingholizadeh, S; Rahnama, R

2014-04-05

The synthesis of CuS nanomaterial in MCM-41 matrix has been realized by chemical synthesis between MCM-41, copper sulfate pentahydrate and thiourea via a solvothermal method in ethylene glycol and water, separately. X-ray diffraction analysis (XRD), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fourier transform infrared (FT-IR) were used to characterize the products. At synthesized CuS/MCM-41 sample in ethylene glycol, X-ray diffraction and diffuse reflectance spectroscopy showed pure covellite phase of copper sulfide with high crystality. But prepared CuS/MCM-41 sample in water shows the covellite, chalcocite and the djurleite phase of copper sulfide nanostructures. The formation of CuS nanostructures was confirmed by FT-IR. Photocatalytic activity of CuS/MCM-41 nanocomposites was studied for degradation of Methylene Blue (MB) under visible light. The CuS/MCM-41 nanocomposite is more effective nanocatalyst than synthesized CuS/MCM-41 sample in water for degradation of methylene blue. Several parameters were examined, catalyst amount (0.1-1gL(-1)), pH (1-13) and initial concentration of MB (0.96-10ppm). The extent of degradation was estimated from the residual concentration by spectrophotometrically. The support size was obtained in the range 60-145nm by TEM. In the same way, the average size of copper sulfide in CuSMCM-41E and CuS/MCM-41W nanostructures were obtained about 10nm and 16nm, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

Bioleaching of Primary Nickel Ore Using Acidithiobacillus ferrooxidans LR Cells Immobilized in Glass Beads

Directory of Open Access Journals (Sweden)

Ellen Cristine Giese

2015-06-01

Full Text Available Sulphide minerals are one of the most important sources of value metals. For several years, a large number of hydrometallurgical and biotechnological processes have been developed to leach low-grade sulphide ores and the conditions are well established. However, the management of microorganisms in the bioleaching process is not easy to handle. In this paper, the use of immobilized cells of Acidithiobacillus ferrooxidans LR in glass beads in bioleaching of primary nickel ore was evaluated. The column experiments inoculated with immobilized cells of A. ferrooxidans LR showed the same efficiency than the conventional method using free cells and is promising for application on a larger scale as it ensuring integrity and activity of biomining microorganisms and reduce process costs. DOI: http://dx.doi.org/10.17807/orbital.v7i2.698 

Phosphate Favors the Biosynthesis of CdS Quantum Dots in Acidithiobacillus thiooxidans ATCC 19703 by Improving Metal Uptake and Tolerance

Directory of Open Access Journals (Sweden)

Giovanni Ulloa

2018-02-01

Full Text Available Recently, we reported the production of Cadmium sulfide (CdS fluorescent semiconductor nanoparticles (quantum dots, QDs by acidophilic bacteria of the Acidithiobacillus genus. Here, we report that the addition of inorganic phosphate to Acidithiobacillus thiooxidans ATCC 19703 cultures favors the biosynthesis of CdS QDs at acidic conditions (pH 3.5. The effect of pH, phosphate and cadmium concentrations on QDs biosynthesis was studied by using Response Surface Methodology (RSM, a multivariate technique for analytical optimization scarcely used in microbiological studies to date. To address how phosphate affects intracellular biosynthesis of CdS QDs, the effect of inorganic phosphate on bacterial cadmium-uptake was evaluated. By measuring intracellular levels of cadmium we determined that phosphate influences the capacity of cells to incorporate this metal. A relation between cadmium tolerance and phosphate concentrations was also determined, suggesting that phosphate participates in the adaptation of bacteria to toxic levels of this metal. In addition, QDs-biosynthesis was also favored by the degradation of intracellular polyphosphates. Altogether, our results indicate that phosphate contributes to A. thiooxidans CdS QDs biosynthesis by influencing cadmium uptake and cadmium tolerance. These QDs may also be acting as a nucleation point for QDs formation at acidic pH. This is the first study reporting the effect of phosphates on QDs biosynthesis and describes a new cadmium-response pathway present in A. thiooxidans and most probably in other bacterial species.

Phosphate Favors the Biosynthesis of CdS Quantum Dots in Acidithiobacillus thiooxidans ATCC 19703 by Improving Metal Uptake and Tolerance

Science.gov (United States)

Ulloa, Giovanni; Quezada, Carolina P.; Araneda, Mabel; Escobar, Blanca; Fuentes, Edwar; Álvarez, Sergio A.; Castro, Matías; Bruna, Nicolás; Espinoza-González, Rodrigo; Bravo, Denisse; Pérez-Donoso, José M.

2018-01-01

Recently, we reported the production of Cadmium sulfide (CdS) fluorescent semiconductor nanoparticles (quantum dots, QDs) by acidophilic bacteria of the Acidithiobacillus genus. Here, we report that the addition of inorganic phosphate to Acidithiobacillus thiooxidans ATCC 19703 cultures favors the biosynthesis of CdS QDs at acidic conditions (pH 3.5). The effect of pH, phosphate and cadmium concentrations on QDs biosynthesis was studied by using Response Surface Methodology (RSM), a multivariate technique for analytical optimization scarcely used in microbiological studies to date. To address how phosphate affects intracellular biosynthesis of CdS QDs, the effect of inorganic phosphate on bacterial cadmium-uptake was evaluated. By measuring intracellular levels of cadmium we determined that phosphate influences the capacity of cells to incorporate this metal. A relation between cadmium tolerance and phosphate concentrations was also determined, suggesting that phosphate participates in the adaptation of bacteria to toxic levels of this metal. In addition, QDs-biosynthesis was also favored by the degradation of intracellular polyphosphates. Altogether, our results indicate that phosphate contributes to A. thiooxidans CdS QDs biosynthesis by influencing cadmium uptake and cadmium tolerance. These QDs may also be acting as a nucleation point for QDs formation at acidic pH. This is the first study reporting the effect of phosphates on QDs biosynthesis and describes a new cadmium-response pathway present in A. thiooxidans and most probably in other bacterial species. PMID:29515535

Sulfur metabolism in the extreme acidophile Acidithiobacillus caldus

Directory of Open Access Journals (Sweden)

Stefanie eMangold

2011-02-01

Full Text Available Given the challenges to life at low pH, an analysis of inorganic sulfur compound oxidation was initiated in the chemolithoautotrophic extremophile Acidithiobacillus caldus. A. caldus is able to metabolize elemental sulfur and a broad range of inorganic sulfur compounds. It has been implicated in the production of environmentally damaging acidic solutions as well as participating in industrial bioleaching operations where it forms part of microbial consortia used for the recovery of metal ions. Based upon the recently published A. caldus type strain genome sequence, a bioinformatic reconstruction of elemental sulfur and inorganic sulfur compound metabolism predicted genes included: sulfide quinone reductase (sqr, tetrathionate hydrolase (tth, two sox gene clusters potentially involved in thiosulfate oxidation (soxABXYZ, sulfur oxygenase reductase (sor, and various electron transport components. RNA transcript profiles by semi-quantitative reverse transcription PCR suggested up-regulation of sox genes in the presence of tetrathionate. Extensive gel based proteomic comparisons of total soluble and membrane enriched protein fractions during growth on elemental sulfur and tetrathionate identified differential protein levels from the two Sox clusters as well as several chaperone and stress proteins up-regulated in the presence of elemental sulfur. Proteomics results also suggested the involvement of heterodisulfide reductase (HdrABC in A. caldus inorganic sulfur compound metabolism. A putative new function of Hdr in acidophiles is discussed. Additional proteomic analysis evaluated protein expression differences between cells grown attached to solid, elemental sulfur versus planktonic cells. This study has provided insights into sulfur metabolism of this acidophilic chemolithotroph and gene expression during attachment to solid elemental sulfur.

Changes in nutrient profile of soil subjected to bioleaching for removal of heavy metals using Acidithiobacillus thiooxidans

International Nuclear Information System (INIS)

NareshKumar, R.; Nagendran, R.

2008-01-01

Studies were carried out to assess changes in nitrogen, phosphorus and potassium contents in soil during bioleaching of heavy metals from soil contaminated by tannery effluents. Indigenous sulfur oxidizing bacteria Acidithiobacillus thiooxidans isolated from the contaminated soil were used for bioremediation. Solubilization efficiency of chromium, cadmium, copper and zinc from soil was 88, 93, 92 and 97%, respectively. However, loss of nitrogen, phosphorus and potassium from the soil was 30, 70 and 68%, respectively. These findings indicate that despite its high potential for removal of heavy metals from contaminated soils, bioleaching results in undesirable dissolution/loss of essential plant nutrients. This aspect warrants urgent attention and detailed studies to evaluate the appropriateness of the technique for field application

Changes in nutrient profile of soil subjected to bioleaching for removal of heavy metals using Acidithiobacillus thiooxidans

Energy Technology Data Exchange (ETDEWEB)

NareshKumar, R. [Centre for Environmental Studies, Anna University, Chennai 600025 (India)], E-mail: nareshkrish@hotmail.com; Nagendran, R. [Centre for Environmental Studies, Anna University, Chennai 600025 (India)

2008-08-15

Studies were carried out to assess changes in nitrogen, phosphorus and potassium contents in soil during bioleaching of heavy metals from soil contaminated by tannery effluents. Indigenous sulfur oxidizing bacteria Acidithiobacillus thiooxidans isolated from the contaminated soil were used for bioremediation. Solubilization efficiency of chromium, cadmium, copper and zinc from soil was 88, 93, 92 and 97%, respectively. However, loss of nitrogen, phosphorus and potassium from the soil was 30, 70 and 68%, respectively. These findings indicate that despite its high potential for removal of heavy metals from contaminated soils, bioleaching results in undesirable dissolution/loss of essential plant nutrients. This aspect warrants urgent attention and detailed studies to evaluate the appropriateness of the technique for field application.

Comparison Analysis of Coal Biodesulfurization and Coal's Pyrite Bioleaching with Acidithiobacillus ferrooxidans

Science.gov (United States)

Hong, Fen-Fen; He, Huan; Liu, Jin-Yan; Tao, Xiu-Xiang; Zheng, Lei; Zhao, Yi-Dong

2013-01-01

Acidithiobacillus ferrooxidans (A. ferrooxidans) was applied in coal biodesulfurization and coal's pyrite bioleaching. The result showed that A. ferrooxidans had significantly promoted the biodesulfurization of coal and bioleaching of coal's pyrite. After 16 days of processing, the total sulfur removal rate of coal was 50.6%, and among them the removal of pyritic sulfur was up to 69.9%. On the contrary, after 12 days of processing, the coal's pyrite bioleaching rate was 72.0%. SEM micrographs showed that the major pyrite forms in coal were massive and veinlets. It seems that the bacteria took priority to remove the massive pyrite. The sulfur relative contents analysis from XANES showed that the elemental sulfur (28.32%) and jarosite (18.99%) were accumulated in the biotreated residual coal. However, XRD and XANES spectra of residual pyrite indicated that the sulfur components were mainly composed of pyrite (49.34%) and elemental sulfur (50.72%) but no other sulfur contents were detected. Based on the present results, we speculated that the pyrite forms in coal might affect sulfur biooxidation process. PMID:24288464

Effect of Extracellular Polymeric Substances on Surface Properties and Attachment Behavior of Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

Qian Li

2016-09-01

Full Text Available Bacterial contact leaching of ores is more effective than non-contact leaching. Adhesion is the first step for leaching bacteria to form a biofilm on a mineral surface. Extracellular polymeric substances (EPS are pivotal for mediating bacterial adhesion to a substratum. In order to clarify the role of EPS, we measured the adhesion forces between chalcopyrite-, sulfur- or FeSO4·7H2O-grown cells of Acidithiobacillus ferrooxidans and chalcopyrite by an atomic force microscope (AFM before and after EPS removal. Surface properties of these cells were assessed by measurements of the contact angle, zeta potential, Fourier transform infrared spectroscopy (FTIR and acid-base titration. Bacterial attachment to chalcopyrite was monitored for 140 min. The results indicate that the EPS control the surface properties of the cells. In addition, the surface properties are decisive for adhesion. The adhesion forces and the amounts of attached cells decreased dramatically after removing EPS, which was not dependent on the preculture.

Type IV pili of Acidithiobacillus ferrooxidans can transfer electrons from extracellular electron donors.

Science.gov (United States)

Li, Yongquan; Li, Hongyu

2014-03-01

Studies on Acidithiobacillus ferrooxidans accepting electrons from Fe(II) have previously focused on cytochrome c. However, we have discovered that, besides cytochrome c, type IV pili (Tfp) can transfer electrons. Here, we report conduction by Tfp of A. ferrooxidans analyzed with a conducting-probe atomic force microscope (AFM). The results indicate that the Tfp of A. ferrooxidans are highly conductive. The genome sequence of A. ferrooxidans ATCC 23270 contains two genes, pilV and pilW, which code for pilin domain proteins with the conserved amino acids characteristic of Tfp. Multiple alignment analysis of the PilV and PilW (pilin) proteins indicated that pilV is the adhesin gene while pilW codes for the major protein element of Tfp. The likely function of Tfp is to complete the circuit between the cell surface and Fe(II) oxides. These results indicate that Tfp of A. ferrooxidans might serve as biological nanowires transferring electrons from the surface of Fe(II) oxides to the cell surface. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison Analysis of Coal Biodesulfurization and Coal’s Pyrite Bioleaching with Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

Fen-Fen Hong

2013-01-01

Full Text Available Acidithiobacillus ferrooxidans (A. ferrooxidans was applied in coal biodesulfurization and coal’s pyrite bioleaching. The result showed that A. ferrooxidans had significantly promoted the biodesulfurization of coal and bioleaching of coal’s pyrite. After 16 days of processing, the total sulfur removal rate of coal was 50.6%, and among them the removal of pyritic sulfur was up to 69.9%. On the contrary, after 12 days of processing, the coal’s pyrite bioleaching rate was 72.0%. SEM micrographs showed that the major pyrite forms in coal were massive and veinlets. It seems that the bacteria took priority to remove the massive pyrite. The sulfur relative contents analysis from XANES showed that the elemental sulfur (28.32% and jarosite (18.99% were accumulated in the biotreated residual coal. However, XRD and XANES spectra of residual pyrite indicated that the sulfur components were mainly composed of pyrite (49.34% and elemental sulfur (50.72% but no other sulfur contents were detected. Based on the present results, we speculated that the pyrite forms in coal might affect sulfur biooxidation process.

Bioleaching of nickel from spent petroleum catalyst using Acidithiobacillus thiooxidans DSM- 11478.

Science.gov (United States)

Sharma, Mohita; Bisht, Varsha; Singh, Bina; Jain, Pratiksha; Mandal, Ajoy K; Lal, Banwari; Sarma, Priyangshu M

2015-06-01

The present work deals with optimization of culture conditions and process parameters for bioleaching of spent petroleum catalyst collected from a petroleum refinery. The efficacy of Ni bioleaching from spent petroleum catalyst was determined using pure culture of Acidithiobacillus thiooxidans DSM- 11478. The culture conditions of pH, temperature and headspace volume to media volume ratio were optimized. EDX analysis was done to confirm the presence of Ni in the spent catalyst after roasting it to decoke its surface. The optimum temperature for A. thiooxidans DSM-11478 growth was found to be 32 degrees C. The enhanced recovery of nickel at very low pH was attributed to the higher acidic strength of sulfuric acid produced in the culture medium by the bacterium. During the bioleaching process, 89% of the Ni present in the catalyst waste could be successfully recovered in optimized conditions. This environment friendly bioleaching process proved efficient than the chemical method. Taking leads from the lab scale results, bioleaching in larger volumes (1, 5 and 10 L) was also performed to provide guidelines for taking up this technology for in situ industrial waste management.

A Tyrosine-Dependent Riboswitch Controls the Expression of a Tyrosyl-tRNA Synthetase from Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

Paula Bustamante

2016-06-01

Full Text Available Expression of aminoacyl-tRNA synthetases is regulated by a variety of mechanisms at the level of transcription or translation. A T-box dependent transcription termination / antitermination riboswitch system that responds to charged / uncharged tRNA regulates expression of aminoacyl tRNA synthetase genes in Gram-positive bacteria. TyrZ, the gene encoding tyrosyl-tRNA synthetase from Acidithiobacillus ferrooxidans, a Gram-negative acidophilic bacterium that participates in bioleaching of minerals, resembles the gene from Bacillus subtilis including the 5´-untranslated region encoding the riboswitch. Transcription of A. ferrooxidans tyrZ is induced by the presence of tyrosine by a mechanism involving antitermination of transcription. This mechanism is probably adapted to the low supply of amino acids of acidic environments of autotrophic bioleaching microorganisms. This work is licensed under a Creative Commons Attribution 4.0 International License.

Acidithiobacillus ferrooxidans metabolism: from genome sequence to industrial applications

Directory of Open Access Journals (Sweden)

Blake Robert

2008-12-01

Full Text Available Abstract Background Acidithiobacillus ferrooxidans is a major participant in consortia of microorganisms used for the industrial recovery of copper (bioleaching or biomining. It is a chemolithoautrophic, γ-proteobacterium using energy from the oxidation of iron- and sulfur-containing minerals for growth. It thrives at extremely low pH (pH 1–2 and fixes both carbon and nitrogen from the atmosphere. It solubilizes copper and other metals from rocks and plays an important role in nutrient and metal biogeochemical cycling in acid environments. The lack of a well-developed system for genetic manipulation has prevented thorough exploration of its physiology. Also, confusion has been caused by prior metabolic models constructed based upon the examination of multiple, and sometimes distantly related, strains of the microorganism. Results The genome of the type strain A. ferrooxidans ATCC 23270 was sequenced and annotated to identify general features and provide a framework for in silico metabolic reconstruction. Earlier models of iron and sulfur oxidation, biofilm formation, quorum sensing, inorganic ion uptake, and amino acid metabolism are confirmed and extended. Initial models are presented for central carbon metabolism, anaerobic metabolism (including sulfur reduction, hydrogen metabolism and nitrogen fixation, stress responses, DNA repair, and metal and toxic compound fluxes. Conclusion Bioinformatics analysis provides a valuable platform for gene discovery and functional prediction that helps explain the activity of A. ferrooxidans in industrial bioleaching and its role as a primary producer in acidic environments. An analysis of the genome of the type strain provides a coherent view of its gene content and metabolic potential.

Diguanylate cyclase null mutant reveals that C-Di-GMP pathway regulates the motility and adherence of the extremophile bacterium Acidithiobacillus caldus.

Directory of Open Access Journals (Sweden)

Matías Castro

Full Text Available An understanding of biofilm formation is relevant to the design of biological strategies to improve the efficiency of the bioleaching process and to prevent environmental damages caused by acid mine/rock drainage. For this reason, our laboratory is focused on the characterization of the molecular mechanisms involved in biofilm formation in different biomining bacteria. In many bacteria, the intracellular levels of c-di-GMP molecules regulate the transition from the motile planktonic state to sessile community-based behaviors, such as biofilm development, through different kinds of effectors. Thus, we recently started a study of the c-di-GMP pathway in several biomining bacteria including Acidithiobacillus caldus. C-di-GMP molecules are synthesized by diguanylate cyclases (DGCs and degraded by phosphodiesterases (PDEs. We previously reported the existence of intermediates involved in c-di-GMP pathway from different Acidithiobacillus species. Here, we report our work related to At. caldus ATCC 51756. We identified several putative-ORFs encoding DGC and PDE and effector proteins. By using total RNA extracted from At. caldus cells and RT-PCR, we demonstrated that these genes are expressed. We also demonstrated the presence of c-di-GMP by mass spectrometry and showed that genes for several of the DGC enzymes were functional by heterologous genetic complementation in Salmonella enterica serovar Typhimurium mutants. Moreover, we developed a DGC defective mutant strain (Δc1319 that strongly indicated that the c-di-GMP pathway regulates the swarming motility and adherence to sulfur surfaces by At. caldus. Together, our results revealed that At. caldus possesses a functional c-di-GMP pathway which could be significant for ores colonization during the bioleaching process.

A Lux-like Quorum Sensing System in the Extreme Acidophile Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

MARIELLA RIVAS

2005-01-01

Full Text Available The genome of the acidophilic, proteobacterium Acidithiobacillus ferrooxidans, contains linked but divergently oriented genes, termed afeI and afeR, whose predicted protein products are significantly similar to the LuxI and LuxR families of proteins. A possible promoter and Lux box are predicted upstream of afeI. A cloned copy of afeI, expressed in E. coli, encodes an enzyme that catalyzes the production of a diffusible compound identified by gas chromatography and mass spectrometry as an unsubstituted N-acyl homoserine lactone (AHL of chain length C14. This AHL can be detected by a reporter strain of Sinorhizobium meliloti Rm41 suggesting that it is biologically active. The reporter strain also responds to extracts of the supernatant of A. ferrooxidans grown to early stationary phase in sulfur medium indicating that a diffusible AHL is produced by this microorganism. Semi-quantitative RT-PCR experiments indicate that afeI and afeR are expressed maximally in early stationary phase and are more expressed when A. ferrooxidans is grown in sulfur- rather than iron-containing medium. Given the predicted amino acid sequence and functional properties of AfeI and AfeR it is proposed that A. ferrooxidans has a quorum sensing system similar to the LuxI-LuxR paradigm.

Caracterización mineralógica de los productosde oxidación del sistema pirita-esfalerita por bacterias nativas oxidantes de Fe

Directory of Open Access Journals (Sweden)

DIONI MABEL ZAPATA AGUIRRE

2008-01-01

Full Text Available La biooxidación de esfalerita y pirita fue evaluada a nivel de shaker utilizando microorganismos acidófilos compatibles con Acidithiobacillus ferrooxidans, a diferentes porcentajes de pulpa y temperatura de 35ºC. Análisis por SEM evidenciaron morfologías y mecanismos de oxidación diferentes para los dos sulfuros. La esfalerita presenta una capa de azufre elemental que bordea núcleos remanentes, los cuales a su vez muestran golfos de corrosión, evidenciando la actividad oxidante del medio. Las capas de azufre muestran morfologías típicas de precipitación a partir de soluciones generadas por la lixiviación de los sulfuros presentes. De otro lado, en la pirita la oxidación se ve reflejada en los golfos y pits de corrosión, sin que se observen películas de azufre. Además del azufre elemental, el principal producto generado durante el proceso fue jarosita. La secuencia de formación de estas fases, así como la oxidación preferencial de la esfalerita sobre la pirita fueron evidenciadas.

Inhibition of microbial concrete corrosion by Acidithiobacillus thiooxidans with functionalised zeolite-A coating.

Science.gov (United States)

Haile, Tesfaalem; Nakhla, George

2009-01-01

The inhibition of the corrosive action of Acidithiobacillus thiooxidans on concrete specimens coated by functionalised zeolite-A containing 14% zinc and 5% silver by weight was studied. Uncoated concrete specimens, epoxy-coated concrete specimens (EP), and functionalised zeolite-A coated concrete specimens with epoxy to zeolite weight ratios of 3:1 (Z1), 2:2 (Z2) and 1:3 (Z3) were studied. Specimens were characterised by x-ray powder diffraction and field emission scanning electron microscopy for the identification of corrosion products and morphological changes. Biomass growth at the conclusion of the 32-day experiments was 4, 179 and 193 mg volatile suspended solids g(-1) sulphur for the uncoated, EP and Z1 specimens, whereas that of Z2 and Z3 were negligible. In the uncoated, EP and Z1 specimens, sulphate production rates were 0.83, 9.1 and 8.8 mM SO(4)(2-) day(-1) and the specific growth rates, mu, were 0.14, 0.57 and 0.47 day(-1), respectively. The corresponding values for Z2 and Z3 were negligible due to their bacterial inhibition characteristics.

InPhoCUS (Inflated Photovoltaic Ultra-light Mirror Concentrators): First Results Of The Project And Future Perspectives

Science.gov (United States)

Pravettoni, Mauro; Barbato, Maurizio; Cooper, Thomas; Pedretti, Andrea; Ambrosetti, Gianluca; Steinfeld, Aldo

2011-12-01

InPhoCUS (Inflated PhotovoltaiC Ultra-light mirror concentratorS) is a concentrating photovoltaic (CPV) project funded by the Swiss Confederation's Innovation Promotion Agency (CTI) and developed by Airlight Energy Holding SA, the University of Applied Sciences and Arts of Southern Switzerland and the Swiss Federal Institute of Technology. The proposed novel concentrating system has already been patented for concentrated solar power applications: it is made by unconventional pneumatic multilayer polymeric mirrors, has an innovative fibre-reinforced concrete structure and an original tilting mechanism to track the sun. The innovative CPV solar collector is profitable for electric power plants both for the sun-belt region and in the Mediterranean. In this paper the authors present the novel CPV system and preliminary results on cost analysis, optical design and thermal modelling.

Figurar la guerra. Sujeto y estilo en Os cus de Judas de António Lobo Antunes

Directory of Open Access Journals (Sweden)

Víctor Escudero

2014-06-01

António Lobo Antunes’ second novel, Os cus de Judas, is a pioneer novel of the Portuguese colonial war literary tradition. Published in 1979, the book becomes part of the author’s first narrative project of finding a self-expression through a narration which goes beyond every single novel. The article explores how that esthetical project faces the linguistic and literary problematics of presenting the testimonial point of view that deals with a traumatic experience such as war, by means of a literary style that always underlines its own rhetoric nature. The language, as a communicative tool and as an autarchic exercise as well, will facilitate and limit the possibility of giving sense to a subjective experience that is trying to be told as a collective intimacy, shared by a silenced generation.

Particle Size Effects in Bio leaching of Uranium From Saghand Ore by Acidithiobacillus Ferroxidans (A.f.)

International Nuclear Information System (INIS)

Rashidi, A.; Roosta Azad, R.; Safdari, S. J.

2012-01-01

The effect of mineral particle size on the bio leaching of uranium from Saghand mine (anomaly 1 and 2) by acidophilic mesophile Acidithiobacillus ferroxidans was investigated in a shake flask. The findings are indicating that this strain is suitable for the uranium recovery from the mentioned ore. In the range of our studies the uranium recovery is faster in the case of d 80 =108 micron from anomaly 1, while, a comminution level of d 80 =160 micron was obtained as an appropriate size for the anomaly 2. The results showed that the particle size distribution of the mineral in this range did not considerably influence the microbial activity. Also, based on the results of bacterial oxidation, the negative effects and toxicity due to the presence of solid and solute components do not put a limit on the microbial activity, and at the tested parameters range, the grown microbial population is performing the desired process excellently.

Zinc bioleaching from an iron concentrate using Acidithiobacillus ferrooxidans strain from Hercules Mine of Coahuila, Mexico

Science.gov (United States)

Núñez-Ramírez, Diola Marina; Solís-Soto, Aquiles; López-Miranda, Javier; Pereyra-Alférez, Benito; Rutiaga-Quiñónes, Miriam; Medina-Torres, Luis; Medrano-Roldán, Hiram

2011-10-01

The iron concentrate from Hercules Mine of Coahuila, Mexico, which mainly contained pyrite and pyrrhotite, was treated by the bioleaching process using native strain Acidithiobacillus ferrooxidans ( A. ferrooxidans) to determine the ability of these bacteria on the leaching of zinc. The native bacteria were isolated from the iron concentrate of the mine. The bioleaching experiments were carried out in shake flasks to analyze the effects of pH values, pulp density, and the ferrous sulfate concentration on the bioleaching process. The results obtained by microbial kinetic analyses for the evaluation of some aspects of zinc leaching show that the native bacteria A. ferrooxidans, which is enriched with a 9K Silverman medium under the optimum conditions of pH 2.0, 20 g/L pulp density, and 40 g/L FeSO4, increases the zinc extraction considerably observed by monitoring during15 d, i.e., the zinc concentration has a decrease of about 95% in the iron concentrate.

[Effect of simulated inorganic anion leaching solution of electroplating sludge on the bioactivity of Acidithiobacillus ferrooxidans].

Science.gov (United States)

Chen, Yan; Huang, Fang; Xie, Xin-Yuan

2014-04-01

An Acidithiobacillus ferrooxidans strain WZ-1 (GenBank sequence number: JQ968461) was used as the research object. The effects of Cl-, NO3-, F- and 4 kinds of simulated inorganic anions leaching solutions of electroplating sludge on the bioactivity of Fe2+ oxidation and apparent respiratory rate of WZ-1 were investigated. The results showed that Cl-, NO3(-)- didn't have any influence on the bioactivity of WZ-1 at concentrations of 5.0 g x L(-1), 1.0 g x L(-1), respectively. WZ-1 showed tolerance to high levels of Cl- and NO3- (about 10.0 g x L(-1), 5.0 g x L(-1), respectively), but it had lower tolerance to F- (25 mg x L(-1)). Different kinds of simulated inorganic anions leaching solutions of electroplating sludge had significant differences in terms of their effects on bioactivity of WZ-1 with a sequence of Cl-/NO3(-)/F(-) > or = NO3(-)/F(-) > Cl-/F(-) > Cl(-)/NO3(-).

Preferência por tipos de liderança: um estudo em empresa sergipana do setor hoteleiro

Directory of Open Access Journals (Sweden)

Marley Rosana Melo de Araújo

2013-06-01

Full Text Available Segundo a Teoria Caminho-Meta de liderança, testada empiricamente nesta pesquisa em setor hoteleiro de Aracaju-SE, há quatro tipos de comportamento do líder (diretivo, de apoio, orientado para realizações e participativo e dois tipos de variáveis situacionais (atributos dos subordinados e do ambiente de trabalho. Nossos objetivos foram identificar o tipo de liderança preferido entre os funcionários; descrever como características dos subordinados (variáveis lócus de controle, percepção de autoeficácia, autoritarismo, necessidade de estruturação comparecem; e associar estes atributos ao estilo de liderança selecionado preponderantemente. Todo o quadro de pessoal (30 pessoas participou do levantamento. Os resultados demonstraram que houve preferência significativa pela liderança de apoio. Os participantes demonstraram relativo grau de autoritarismo e um alto escore em percepção de autoeficácia. Por fim, também foi encontrada uma provável associação entre maiores escores na variável percepção de autoeficácia e a preferência por tipos de liderança mais participativos e de apoio.

Characterization of bornite (Cu5FeS4 electrodes in the presence of the bacterium Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

Bevilaqua Denise

2003-01-01

Full Text Available Bornite electrodes were characterized in the absence or in the presence of Acidithiobacillus ferrooxidans, which is an important microorganism involved in metal bioleaching processes. The presence of the bacterium modified the mineral/electrolyte interface, increasing the corrosion rate, as revealed by interferometric, AEM, ICP and EIS analyses. As a consequence of bacterial activity the electrode became porous, increasing its surface heterogeneity. This behavior was correlated with the evolution of impedance diagrams obtained during the time course of experiments. The main difference in these diagrams was the presence of an inductive feature (up to 44 h, which was related to bacterial action on the mineral dissolution, better than to its adhesion on the bornite. The total real impedance measured in presence of the bacterium was about 10 times lower than in its absence, due to the acceleration of the mineral dissolution, because an oxidant environment was maintained.

Novel integration strategy for enhancing chalcopyrite bioleaching by Acidithiobacillus sp. in a 7-L fermenter.

Science.gov (United States)

Feng, Shoushuai; Yang, Hailin; Zhan, Xiao; Wang, Wu

2014-06-01

An integrated strategy (additional energy substrate-three stage pH control-fed batch) was firstly proposed for efficiently improving chalcopyrite bioleaching by Acidithiobacillus sp. in a 7-L fermenter. The strain adaptive-growing phase was greatly shortened from 8days into 4days with the supplement of additional 2g/L Fe(2+)+2g/L S(0). Jarosite passivation was effectively weakened basing on higher biomass via the three-stage pH-stat control (pH 1.3-1.0-0.7). The mineral substrate inhibition was attenuated by fed-batch fermentation. With the integrated strategy, the biochemical reaction was promoted and achieved a better balance. Meanwhile, the domination course of A. thiooxidans in the microbial community was shortened from 14days to 8days. As the results of integrated strategy, the final copper ion and productivity reached 89.1mg/L and 2.23mg/(Ld), respectively, which was improved by 52.8% compared to the uncontrolled batch bioleaching. The integrated strategy could be further exploited for industrial chalcopyrite bioleaching. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microarray and bioinformatic analyses suggest models for carbon metabolism in the autotroph Acidithiobacillus ferrooxidans

Energy Technology Data Exchange (ETDEWEB)

C. Appia-ayme; R. Quatrini; Y. Denis; F. Denizot; S. Silver; F. Roberto; F. Veloso; J. Valdes; J. P. Cardenas; M. Esparza; O. Orellana; E. Jedlicki; V. Bonnefoy; D. Holmes

2006-09-01

Acidithiobacillus ferrooxidans is a chemolithoautotrophic bacterium that uses iron or sulfur as an energy and electron source. Bioinformatic analysis was used to identify putative genes and potential metabolic pathways involved in CO2 fixation, 2P-glycolate detoxification, carboxysome formation and glycogen utilization in At. ferrooxidans. Microarray transcript profiling was carried out to compare the relative expression of the predicted genes of these pathways when the microorganism was grown in the presence of iron versus sulfur. Several gene expression patterns were confirmed by real-time PCR. Genes for each of the above predicted pathways were found to be organized into discrete clusters. Clusters exhibited differential gene expression depending on the presence of iron or sulfur in the medium. Concordance of gene expression within each cluster, suggested that they are operons Most notably, clusters of genes predicted to be involved in CO2 fixation, carboxysome formation, 2P-glycolate detoxification and glycogen biosynthesis were up-regulated in sulfur medium, whereas genes involved in glycogen utilization were preferentially expressed in iron medium. These results can be explained in terms of models of gene regulation that suggest how A. ferrooxidans can adjust its central carbon management to respond to changing environmental conditions.

Effect of calcium oxide on the efficiency of ferrous ion oxidation and total iron precipitation during ferrous ion oxidation in simulated acid mine drainage treatment with inoculation of Acidithiobacillus ferrooxidans.

Science.gov (United States)

Liu, Fenwu; Zhou, Jun; Jin, Tongjun; Zhang, Shasha; Liu, Lanlan

2016-01-01

Calcium oxide was added into ferrous ion oxidation system in the presence of Acidithiobacillus ferrooxidans at concentrations of 0-4.00 g/L. The pH, ferrous ion oxidation efficiency, total iron precipitation efficiency, and phase of the solid minerals harvested from different treatments were investigated during the ferrous ion oxidation process. In control check (CK) system, pH of the solution decreased from 2.81 to 2.25 when ferrous ions achieved complete oxidation after 72 h of Acidithiobacillus ferrooxidans incubation without the addition of calcium oxide, and total iron precipitation efficiency reached 20.2%. Efficiency of ferrous ion oxidation and total iron precipitation was significantly improved when the amount of calcium oxide added was ≤1.33 g/L, and the minerals harvested from systems were mainly a mixture of jarosite and schwertmannite. For example, the ferrous ion oxidation efficiency reached 100% at 60 h and total iron precipitation efficiency was increased to 32.1% at 72 h when 1.33 g/L of calcium oxide was added. However, ferrous ion oxidation and total iron precipitation for jarosite and schwertmannite formation were inhibited if the amount of calcium oxide added was above 2.67 g/L, and large amounts of calcium sulfate dihydrate were generated in systems.

Optimization of magnetosome production by Acidithiobacillus ferrooxidans using desirability function approach

International Nuclear Information System (INIS)

Yan, Lei; Zhang, Shuang; Liu, Hetao; Wang, Weidong; Chen, Peng; Li, Hongyu

2016-01-01

Present study aimed to resolve the conflict between cell growth and magnetosome formation of Acidithiobacillus ferrooxidans (A. ferrooxidans) in batch experiments by applying response surface methodology (RSM) integrated a desirability function approach. The effects of several operating parameters on cell growth (OD_6_0_0) and magnetosome production (C_m_a_g) were evaluated. The maximum overall desirability (D) of 0.923 was achieved at iron concentration of 125.07 mM, shake speed of 122.37 rpm and nitrogen concentration of 2.40 g/L. Correspondingly, the OD_6_0_0 and C_m_a_g were 0.522 and 1.196, respectively. The confirmation experiment confirmed that the optimum OD_6_0_0 and C_m_a_g obtained were in good agreement with the predicted values. The inductively coupled plasma atomic emission spectrometer (ICP-AES) and transmission electron microscopy (TEM) analyses revealed that the production of magnetosomes could be improved via optimization. X-ray diffraction (XRD) showed the magnetosomes are magnetite. Results indicated that RSM with a desirability function was a useful technique to get the maximum OD_6_0_0 and C_m_a_g simultaneously. - Highlights: • Optimization of magnetosome production by A. ferrooxidans using BBD of RSM. • Desirability function was used for concurrent maximization of cell and magnetosome yield. • ICP-AES results showed an increase in intracellular iron content through optimizing. • TEM showed a 2.5 fold increase in magnetosome number after optimization. • The methodology demonstrated a useful tool with an overall desirability of 0.923.

Occurrence and fluctuations of Acidithiobacillus ssp. in uranium mine effluents, Caldas, MG

International Nuclear Information System (INIS)

Campos, Michelle Burato de; Roque, Claudio Vitor; Gomes, Heliana de Azevedo

2007-01-01

Sulphide ores that are present in mining areas can cause serious environmental problems because of the action of chemolithotrophic bacteria of the Acidithiobacillus genera, mainly A. ferroxidans and A. thiooxidans. These microorganisms are capable of oxidizing sulphide minerals, elemental sulphur and ferrous ion, possibly mobilizing radionuclides such as uranium into the environment. In this context, the present study was undertaken in order to determine the occurrence and fluctuations of populations of A. ferroxidans and A. thiooxidans in effluents from an uranium mine, part of the Ore Treatment Unit (UTM) in Caldas, MG - Brazil, analyzing samples from 9 sampling points (CM, BS, D3, 25, 27, 32, 41, 75, and 76). The results showed that the population of A. thiooxidans occurs more often (44.4%) than the population of A. ferroxidans (31.5%). In the sample points within the UTM-environment interface, points 25 and 76 were considered the most susceptible to acid mine drainage and activity of bacteria involved in metal bioleaching. The seasonal behavior of some of the variables observed at points CM, D3, and BS, when evaluated simultaneously, such as high Eh values, low pH values, the detection of greater percentages of incidence and higher counts of A. ferroxidans and A. thiooxidans, showed that these points are the main locations for the occurrence of acid mine drainage and bacterial bioleaching in the UTM and should be considered as critical points for a possible decommissioning action. (author)

Occurrence and fluctuations of Acidithiobacillus ssp. in uranium mine effluents, Caldas, MG

Energy Technology Data Exchange (ETDEWEB)

Campos, Michelle Burato de; Roque, Claudio Vitor; Gomes, Heliana de Azevedo [Brazilian Nuclear Energy Commission (CNEN-MG), Pocos de Caldas, MG (Brazil)]. E-mail: michelle_borato@hotmail.com; cvroque@cnen.gov.br; hgomes@cnen.gov.br

2007-07-01

Sulphide ores that are present in mining areas can cause serious environmental problems because of the action of chemolithotrophic bacteria of the Acidithiobacillus genera, mainly A. ferroxidans and A. thiooxidans. These microorganisms are capable of oxidizing sulphide minerals, elemental sulphur and ferrous ion, possibly mobilizing radionuclides such as uranium into the environment. In this context, the present study was undertaken in order to determine the occurrence and fluctuations of populations of A. ferroxidans and A. thiooxidans in effluents from an uranium mine, part of the Ore Treatment Unit (UTM) in Caldas, MG - Brazil, analyzing samples from 9 sampling points (CM, BS, D3, 25, 27, 32, 41, 75, and 76). The results showed that the population of A. thiooxidans occurs more often (44.4%) than the population of A. ferroxidans (31.5%). In the sample points within the UTM-environment interface, points 25 and 76 were considered the most susceptible to acid mine drainage and activity of bacteria involved in metal bioleaching. The seasonal behavior of some of the variables observed at points CM, D3, and BS, when evaluated simultaneously, such as high Eh values, low pH values, the detection of greater percentages of incidence and higher counts of A. ferroxidans and A. thiooxidans, showed that these points are the main locations for the occurrence of acid mine drainage and bacterial bioleaching in the UTM and should be considered as critical points for a possible decommissioning action. (author)

Oxidation of dibenzothiophene as a model substrate for the removal of organic sulphur from fossil fuels by iron(III ions generated from pyrite by Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

VLADIMIR P. BESKOSKI

2007-06-01

Full Text Available Within this paper a new idea for the removal of organically bonded sulphur from fossil fuels is discussed. Dibenzothiophene (DBT was used as a model compound of organicmolecules containing sulphur. This form of (biodesulphurization was performed by an indirect mechanism in which iron(III ions generated from pyrite by Acidithiobacillus ferrooxidans performed the abiotic oxidation. The obtained reaction products, dibenzothiopene sulfoxide and dibenzothiophene sulfone, are more soluble in water than the basic substrate and the obtained results confirmed the basic hypothesis and give the posibility of continuing the experiments related to application of this (biodesulphurization process.

Bioleaching of arsenic from highly contaminated mine tailings using Acidithiobacillus thiooxidans.

Science.gov (United States)

Lee, Eunseong; Han, Yosep; Park, Jeonghyun; Hong, Jeongsik; Silva, Rene A; Kim, Seungkon; Kim, Hyunjung

2015-01-01

The behavior of arsenic (As) bioleaching from mine tailings containing high amount of As (ca. 34,000 mg/kg) was investigated using Acidithiobacillus thiooxidans to get an insight on the optimal conditions that would be applied to practical heap and/or tank bioleaching tests. Initial pH (1.8-2.2), temperature (25-40 °C), and solid concentration (0.5-4.0%) were employed as experimental parameters. Complementary characterization experiments (e.g., XRD, SEM-EDS, electrophoretic mobility, cell density, and sulfate production) were also carried out to better understand the mechanism of As bioleaching. The results showed that final As leaching efficiency was similar regardless of initial pH. However, greater initial As leaching rate was observed at initial pH 1.8 than other conditions, which could be attributed to greater initial cell attachment to mine tailings. Unlike the trend observed when varying the initial pH, the final As leaching efficiency varied with the changes in temperature and solid concentration. Specifically, As leaching efficiency tended to decrease with increasing temperature due to the decrease in the bacterial growth rate at higher temperature. Meanwhile, As leaching efficiency tended to increase with decreasing solid concentration. The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during the bioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailings by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fe extraction from çayeli copper ores by bioleaching with eco freiendly acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

Kocadagistan, M.E.; Bayhan, Y.K.

2017-01-01

Recently, biological treatment; an important recovery process, has became important from the environmental and economical respects in recovery of metallic values from low-grade sulfur-bearing ores or concentrates. Bacterial ore leaching can be applied to extract heavy metals from low grade ores, industrial wastes and other materials on an industrial scale by different procedures. The main objective of this work was to investigate the dissolution of Fe from Çayeli copper ores, via a bioleaching process using Acidithiobacillus ferrooxidans. Experiments performed with batch operation in jar test equipment were conducted at different pH values, pulp densities, inoculum volumes, particle sizes, stirring conditions and operation times. The optimal parameters were found as follows; at pH 2, the pulp density; 4% (w/v), inoculum volume; 4% (v/v), stirring rate; 120 rpm and particle size; -0.053 mm for 192nd and 288th hours, at pH 2, the pulp density; 4% (w/v), inoculum volume; 5% (v/v), stirring speed; 200 rpm and particle size; -0.053 mm for 384th and 480th hours. By performing the bioleaching process under these conditions, almost 99% of the iron extent in the ore was transfer from ore into solution, however the experiments in which distilled water was used instead of modified 9K*, only 18.5% Fe efficiency was obtained. (author)

Genomic insights into the iron uptake mechanisms of the biomining microorganism Acidithiobacillus ferrooxidans.

Science.gov (United States)

Quatrini, Raquel; Jedlicki, Eugenia; Holmes, David S

2005-12-01

Commercial bioleaching of copper and the biooxidation of gold is a cost-effective and environmentally friendly process for metal recovery. A partial genome sequence of the acidophilic, bioleaching bacterium Acidithiobacillus ferrooxidans is available from two public sources. This information has been used to build preliminary models that describe how this microorganism confronts unusually high iron loads in the extremely acidic conditions (pH 2) found in natural environments and in bioleaching operations. A. ferrooxidans contains candidate genes for iron uptake, sensing, storage, and regulation of iron homeostasis. Predicted proteins exhibit significant amino acid similarity with known proteins from neutrophilic organisms, including conservation of functional motifs, permitting their identification by bioinformatics tools and allowing the recognition of common themes in iron transport across distantly related species. However, significant differences in amino acid sequence were detected in pertinent domains that suggest ways in which the periplasmic and outer membrane proteins of A. ferrooxidans maintain structural integrity and relevant protein-protein contacts at low pH. Unexpectedly, the microorganism also contains candidate genes, organized in operon-like structures that potentially encode at least 11 siderophore systems for the uptake of Fe(III), although it does not exhibit genes that could encode the biosynthesis of the siderophores themselves. The presence of multiple Fe(III) uptake systems suggests that A. ferrooxidans can inhabit aerobic environments where iron is scarce and where siderophore producers are present. It may also help to explain why it cannot tolerate high Fe(III) concentrations in bioleaching operations where it is out-competed by Leptospirillum species.

Bioleaching of heavy metals from sewage sludge by Acidithiobacillus thiooxidans. A comparative study

Energy Technology Data Exchange (ETDEWEB)

Wen, Ye-Ming; Wang, Qing-Ping; Chen, Zu-Liang [Fujian Normal Univ., Fuzhou (China). School of Environmental Science and Engineering; Tang, Caixian [La Trobe Univ., Melbourne, VIC (Australia). Dept. of Agricultural Sciences

2012-06-15

To understand the bioleaching of metals from sludge by Acidithiobacillus thiooxidans, the aims of this study were to evaluate the experimental conditions affecting the efficiency of removal of the metals, including solids concentration, initial pH, sulfur concentration and inoculum level were examined, and following the bioleaching mechanism was proposed. Materials and methods: A. thiooxidans were isolated from collected sludge samples containing bacteria from Fuzhou Jingshan sewage treatment plant, and identification of bacteria by sequencing the 16 s rDNA gene sequences. Conditions affecting the bioleaching and application were conducted by batch experiments. The analysis of Cr, Cu, Pb, and Zn was carried out using an atomic absorption spectrophotometer, and the pH and oxidation-reduction potential (ORP) were measured using a pH meter and an ORP meter. The results show that a high metal leaching efficiency was achieved at low solid concentrations due to decreases in buffering capacity. In addition, the best conditions of the bioleaching included 2 % (w/{nu}) solid concentration, 5.0 gL{sup -1} sulfur concentration, and 10 % ({nu}/{nu}) inoculum concentration, where the removal efficiencies of Cr, Cu, Pb, and Zn in sewage sludge was 43.6 %, 96.2 %, 41.6 %, and 96.5 %, respectively. We found that the bioleaching of Zn was governed by direct and indirect mechanisms, while the bioleaching of Cu, Pb, and Cr was mainly dominated by the bioleaching indirect mechanism. After processing with the proposed techniques, the heavy metals in the sewage sludge did meet the requirement of the national standards. (orig.)

Ex-situ bioremediation of U(VI from contaminated mine water using Acidithiobacillus ferrooxidans strains

Directory of Open Access Journals (Sweden)

Maria eRomero-Gonzalez

2016-05-01

Full Text Available The ex-situ bioremoval of U(VI from contaminated water using Acidithiobacillus ferrooxidans strain 8455 and 13538 was studied under a range of pH and uranium concentrations. The effect of pH on the growth of bacteria was evaluated across the range 1.5 – 4.5 pH units. The respiration rate of At. ferrooxidans at different U(VI concentrations was quantified as a measure of the rate of metabolic activity over time using an oxygen electrode. The biosorption process was quantified using a uranyl nitrate solution, U-spiked growth media and U-contaminated mine water. The results showed that both strains of At. ferrooxidans are able to remove U(VI from solution at pH 2.5 – 4.5, exhibiting a buffering capacity at pH 3.5. The respiration rate of the micro-organism was affected at U(VI concentration of 30 mg L-1. The kinetics of the sorption fitted a pseudo-first order equation, and depended on the concentration of U(VI. The KD obtained from the biosorption experiments indicated that strain 8455 is more efficient for the removal of U(VI. A bioreactor designed to treat a solution of 100 mg U(VI L-1 removed at least 50% of the U(VI in water. The study demonstrated that At. ferrooxidans can be used for the ex-situ bioremediation of U(VI contaminated mine water.

Biosorption and biodegradation of a sulfur dye in high-strength dyeing wastewater by Acidithiobacillus thiooxidans.

Science.gov (United States)

Nguyen, Thai Anh; Fu, Chun-Chieh; Juang, Ruey-Shin

2016-11-01

The ability of the bacterial strain Acidithiobacillus thiooxidans to remove sulfur blue 15 (SB15) dye from water samples was examined. This bacterium could not only oxidize sulfur compounds to sulfuric acid but also promote the attachment of the cells to the surface of sulfidic particles, therefore serving as an efficient biosorbent. The biosorption isotherms were better described by the Langmuir equation than by the Freundlich or Dubinin-Radushkevich equation. Also, the biosorption process followed the pseudo-second-order kinetics. At pH 8.3 and SB15 concentrations up to 2000 mg L(-1) in the biomass/mineral salt solution, the dye removal and decolorization were 87.5% and 91.4%, respectively, following the biosorption process. Biodegradation was proposed as a subsequent process for the remaining dye (250-350 mg L(-1)). A central composite design was used to analyze independent variables in the response surface methodology study. Under the optimal conditions (i.e., initial dye concentration of 300 mg L(-1), initial biomass concentration of 1.0 g L(-1), initial pH of 11.7, and yeast extract dose of 60 mg L(-1)), up to 50% of SB15 was removed after 4 days of biodegradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Locus of control and contraceptive knowledge, attitude and practice among university students Locus de control y conocimiento, actitud y práctica contraceptivas entre adolescentes universitarios Lócus de controle e conhecimento, atitude e prática contraceptivas entre adolescentes universitários

Directory of Open Access Journals (Sweden)

Aline Salheb Alves

2010-02-01

sociodemográficas y variables relacionadas a la vida sexual fueron usadas las pruebas de Kruskal-Wallis y Mann-Whitney. RESULTADOS: Los adolescentes del sexo masculino presentaron mayor externalidad- otros poderosos cuando se compararon con las del sexo femenino (p=0,001. Estudiantes que vivían solos tenían una internalidad más baja (p=0,001. Cuando el locus de control fue comparado con el uso de preservativo en la primera relación sexual, considerándose apenas los 102 estudiantes que informaron la edad de inicio de la actividad sexual, fue encontrada mayor internalidad entre los adolescentes del sexo masculino que no usaron preservativo (p?0,05. Al correlacionar los escores del locus de control con el conocimiento contraceptivo y práctica, se observó que cuanto más elevado el escore del locus de control externalidad otros-poderosos, menor el uso adecuado de métodos contraceptivos (r=-0,22, p=0,03. CONCLUSIONES: El locus externalidad otros-poderosos influencia la práctica de uso de método contraceptivo en ese grupo de adolescentes.OBJETIVO: Avaliar a relação do lócus de controle com conhecimento, atitude e prática relacionados à pílula e ao preservativo entre adolescentes estudantes universitários. MÉTODOS: Estudo tipo inquérito desenvolvido em Campinas, SP, em 2006. O total de 295 adolescentes ingressantes de uma universidade pública respondeu a um questionário estruturado e à escala multidimensional de lócus de controle de Levenson. Foram calculados os escores das dimensões do lócus de controle e o coeficiente de correlação de Spearman para avaliar a correlação com o conhecimento e a prática do uso de pílula e preservativo. Para avaliar a relação entre as dimensões do lócus de controle e as variáveis sociodemográficas e variáveis relacionadas à vida sexual foram usados os testes de Kruskal-Wallis e Mann-Whitney. RESULTADOS: Os adolescentes do sexo masculino apresentaram maior externalidade-outros poderosos quando comparados com as do

Patients in treatment for chronic low back pain have higher externalised beliefs: a cross-sectional study Pacientes em tratamento da dor lombar crônica têm crenças mais externalizadas: um estudo transversal

Directory of Open Access Journals (Sweden)

Thiago H. Oliveira

2012-02-01

: Investigar se existem diferenças no lócus de controle entre os indivíduos com dor lombar crônica em tratamento (grupo tratamento e aqueles que esperam tratamento (grupo controle. MÉTODOS: Cem participantes (50 por grupo com sintomas lombares por pelo menos três meses, com um episódio atual de dor lombar e com idades entre 18 e 60 anos foram recrutados. O Questionário Multidimensional de Lócus de Controle da Saúde (MHLC foi usado para coleta das crenças dos participantes. Realizou-se uma regressão linear múltipla ajustada para incapacidade e para comparação do lócus de controle entre os grupos. As diferenças foram descritas com médias e intervalos de confiança de 95%. RESULTADOS: O grupo tratamento teve escore mais alto para o lócus de controle externo e mais baixo para o lócus de controle interno quando comparado com o grupo controle. As diferenças médias (intervalo de confiança de 95% foram 2,7 pontos em possível diferença de até 30 pontos (0,5 a 4,8 para lócus de controle externo e -2,8 pontos (-5,4 a -0,1 para lócus de controle interno. CONCLUSÃO: O lócus de controle da saúde encontrado para o grupo tratamento e o controle foi diferente. Os participantes em tratamento tinham um alto lócus de controle externo e um baixo lócus de controle interno quando comparados com os do grupo controle.

TECNOLOGIA ASSISTIVA NA PERSPECTIVA DE EDUCAÇÃO INCLUSIVA: O CIBERESPAÇO COMO LÓCUS DE AUTONOMIA E AUTORIA

Directory of Open Access Journals (Sweden)

Maria Dolores Fortes Alves

2017-06-01

Full Text Available Este artigo pretende investigar a contribuição da Tecnologia Assistiva (TA na perspectiva da educação inclusiva e o ciberespaço como lócus ímpar do processo de mediação e construção da autonomia autoria de pensamento dos sujeitos implicados no processo de ensino aprendizagem. A percepção do professor em permitir que a pessoa com deficiência se sinta parte do contexto de ensino aprendizagem e construção da autoria de pensamento, supostamente a inclusão acontecerá de forma efetiva facilitando o aprendizado dos alunos em sua diversidade. A metodologia adotada fundamenta-se na pesquisa qualitativa com abordagem participativa e descritiva. Contudo, entende-se que é um processo complexo, mas que tanto o professor quanto o aluno constituirão uma relação pedagógica que cumpra com a função social da escola na vida dos indivíduos singulares. Diante dos aspectos destacados, as tecnologias e as tecnologias assistivas e inclusão escolar.

Characterization of arsenic resistant and arsenopyrite oxidizing Acidithiobacillus ferrooxidans from Hutti gold leachate and effluents.

Science.gov (United States)

Dave, Shailesh R; Gupta, Kajal H; Tipre, Devayani R

2008-11-01

Four arsenic resistant ferrous oxidizers were isolated from Hutti Gold Mine Ltd. (HGML) samples. Characterization of these isolates was done using conventional microbiological, biochemical and molecular methods. The ferrous oxidation rates with these isolates were 16, 48, 34 and 34 mg L(-1)h(-1) and 15, 47, 34 and 32 mg L(-1)h(-1) in absence and presence of 20 mM of arsenite (As3+) respectively. Except isolate HGM 8, other three isolates showed 2.9-6.3% inhibition due to the presence of 20 mM arsenite. Isolate HGM 8 was able to grow in presence of 14.7 g L(-1) of arsenite, with 25.77 mg L(-1)h(-1) ferrous oxidation rate. All the four isolates were able to oxidize iron and arsenopyrite from 20 g L(-1) and 40 g L(-1) refractory gold ore and 20 g L(-1) refractory gold concentrate. Once the growth was established pH adjustment was not needed inspite of ferrous oxidation, which could be due to concurrent oxidation of pyrite. Isolate HGM 8 showed the final cell count of as high as 1.12 x 10(8) cells mL(-1) in 40 g L(-1) refractory gold ore. The isolates were grouped into one haplotypes by amplified ribosomal DNA restriction analysis (ARDRA). The phylogenetic position of HGM 8 was determined by 16S rDNA sequencing. It was identified as Acidithiobacillus ferrooxidans and strain name was given as SRHGM 1.

Bioinformatic Prediction of Gene Functions Regulated by Quorum Sensing in the Bioleaching Bacterium Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

Alvaro Banderas

2013-08-01

Full Text Available The biomining bacterium Acidithiobacillus ferrooxidans oxidizes sulfide ores and promotes metal solubilization. The efficiency of this process depends on the attachment of cells to surfaces, a process regulated by quorum sensing (QS cell-to-cell signalling in many Gram-negative bacteria. At. ferrooxidans has a functional QS system and the presence of AHLs enhances its attachment to pyrite. However, direct targets of the QS transcription factor AfeR remain unknown. In this study, a bioinformatic approach was used to infer possible AfeR direct targets based on the particular palindromic features of the AfeR binding site. A set of Hidden Markov Models designed to maintain palindromic regions and vary non-palindromic regions was used to screen for putative binding sites. By annotating the context of each predicted binding site (PBS, we classified them according to their positional coherence relative to other putative genomic structures such as start codons, RNA polymerase promoter elements and intergenic regions. We further used the Multiple EM for Motif Elicitation algorithm (MEME to further filter out low homology PBSs. In summary, 75 target-genes were identified, 34 of which have a higher confidence level. Among the identified genes, we found afeR itself, zwf, genes encoding glycosyltransferase activities, metallo-beta lactamases, and active transport-related proteins. Glycosyltransferases and Zwf (Glucose 6-phosphate-1-dehydrogenase might be directly involved in polysaccharide biosynthesis and attachment to minerals by At. ferrooxidans cells during the bioleaching process.

Bioinformatic Prediction of Gene Functions Regulated by Quorum Sensing in the Bioleaching Bacterium Acidithiobacillus ferrooxidans

Science.gov (United States)

Banderas, Alvaro; Guiliani, Nicolas

2013-01-01

The biomining bacterium Acidithiobacillus ferrooxidans oxidizes sulfide ores and promotes metal solubilization. The efficiency of this process depends on the attachment of cells to surfaces, a process regulated by quorum sensing (QS) cell-to-cell signalling in many Gram-negative bacteria. At. ferrooxidans has a functional QS system and the presence of AHLs enhances its attachment to pyrite. However, direct targets of the QS transcription factor AfeR remain unknown. In this study, a bioinformatic approach was used to infer possible AfeR direct targets based on the particular palindromic features of the AfeR binding site. A set of Hidden Markov Models designed to maintain palindromic regions and vary non-palindromic regions was used to screen for putative binding sites. By annotating the context of each predicted binding site (PBS), we classified them according to their positional coherence relative to other putative genomic structures such as start codons, RNA polymerase promoter elements and intergenic regions. We further used the Multiple EM for Motif Elicitation algorithm (MEME) to further filter out low homology PBSs. In summary, 75 target-genes were identified, 34 of which have a higher confidence level. Among the identified genes, we found afeR itself, zwf, genes encoding glycosyltransferase activities, metallo-beta lactamases, and active transport-related proteins. Glycosyltransferases and Zwf (Glucose 6-phosphate-1-dehydrogenase) might be directly involved in polysaccharide biosynthesis and attachment to minerals by At. ferrooxidans cells during the bioleaching process. PMID:23959118

Covellite CuS as a matrix for "invisible" gold: X-ray spectroscopic study of the chemical state of Cu and Au in synthetic minerals

Science.gov (United States)

Tagirov, Boris R.; Trigub, Alexander L.; Kvashnina, Kristina O.; Shiryaev, Andrey A.; Chareev, Dmitriy A.; Nickolsky, Maximilian S.; Abramova, Vera D.; Kovalchuk, Elena V.

2016-10-01

Geological processes leading to formation of sulfide ores often result in precipitation of gold-bearing sulfides which can contain high concentrations of this metal in ;invisible; (or ;refractory;) state. Covellite (CuS) is ubiquitous mineral in many types of the ore deposits, and numerous studies of the natural ores show that covellite can contain high concentrations of Au. At the same time, Au-bearing covellite withstands cooling in contrast to other minerals of the Cu-Fe-S system (chalcocite, bornite, chalcopyrite), where Au exsolves at low temperatures. This makes covellite a convenient model system for investigation of the chemical state (local environment and valence) of the ;invisible; Au in copper-sulfide ores (copper-porphyry, epithermal, volcanogenic massive sulfide, SEDEX deposits). Therefore, it is necessary to determine the location of Au in the covellite matrix as it will have important implications for the methods employed by mineral processing industry to extract Au from sulfide ores. Here we investigate the chemical state of Cu and Au in synthetic covellite containing up to 0.3 wt.% of Au in the ;invisible; state. The covellite crystals were synthesized by hydrothermal and salt flux methods. Formation of the chemically bound Au is indicated by strong dependence of the concentration of Au in covellite on the sulfur fugacity in the experimental system (d(log C(Au))/d(log f(S2)) ∼ 0.65). The Au concentration of covellite grows with increasing temperature from 400 to 450 °C, whereas further temperature increase to 500 °C has only minor effect. The synthesized minerals were studied using X-ray absorption fine structure spectroscopy (XAFS) in high energy resolution fluorescence detection (HERFD) mode. Ab initio simulations of Cu K edge XANES spectra show that the Cu oxidation state in two structural positions in covellite (tetrahedral and triangular coordination with S atoms) is identical: the total loss of electronic charge for the 3d shell is ∼0

Efecto de la cisteína en un proceso de biodepiritización de carbones en lecho empacado

Directory of Open Access Journals (Sweden)

Gerardo Andrés Caicedo Pineda

2016-01-01

Full Text Available Se llevaron a cabo procesos de biodesulfurización de dos carbones colombianos ricos en azufre (“Mina Vieja” y “Vampiro”, en reactores de lecho empacado a nivel de erlenmeyer, utilizando un consorcio de Acidithiobacillus ferrooxidans (ATCC 23270 y Acidithiobacillus thiooxidans (ATCC 15494, evaluando la adición de cisteína a la solución lixiviante. Los ensayos fueron monitoreados por medidas de hierro en solución, pH y potencial redox. Adicionalmente, se hicieron análisis mineralógicos por difracción de rayos X (DRX antes y después de los experimentos. Los ensayos sin adición de cisteína alcanzaron una oxidación de pirita de 45.3% y 57.9% para “Mina Vieja” y “Vampiro” respectivamente. Cuando se adicionó cisteína, la oxidación aumentó en 14.9% para “Mina Vieja” y 6.4% para “Vampiro”. Por otra parte, todos los ensayos evidenciaron remoción de caolinita, debido a su interacción con el ácido sulfúrico del medio. Con base en los resultados obtenidos, los componentes del carbón influenciaron tanto crecimiento bacteriano como la eficiencia de la cisteína sobre el grado de pirita oxidada.

Biosynthesis of schwertmannite by Acidithiobacillus ferrooxidans cell suspensions under different pH condition

Energy Technology Data Exchange (ETDEWEB)

Liao Yuehua [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China); Zhou Lixiang [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)], E-mail: lxzhou@njau.edu.cn; Liang Jianru; Xiong Huixin [Department of Environmental Engineering, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China)

2009-01-01

Oxidation of FeSO{sub 4} solution with initial pH in the range of 1.40-3.51 by Acidithiobacillus ferrooxidans LX5 cell at 26 deg. C and subsequent precipitation of resulting Fe(III) were investigated in the present study. Results showed that the oxidation rate of Fe(II) was around 1.2-3.9 mmol l{sup -1} h{sup -1}. X-ray diffraction (XRD) indicated that the formed precipitates were composed of natrojarosite with schwertmannite when the initial pH was 3.51, while only schwertmannite was produced when initial pH was in the range of 1.60-3.44 and no precipitate occurred when initial pH {<=} 1.40. Scanning electron microscope (SEM) analyses showed that precipitates formed in solution with initial pH 3.51 were spherical particles of about 0.4 {mu}m in diameter and had a smooth surface, whereas precipitates in solution with initial pH {<=} 3.44 were spherical particles of approximately 1.0 {mu}m in diameter, having specific sea-urchin morphology. Specific surface area of the precipitates varied from 3.42 to 23.45 m{sup 2} g{sup -1}. X-ray fluorescence analyses revealed that schwertmannite formed in solution with initial pH in the range of 2.00-3.44 had similar elemental composition and could be expressed as Fe{sub 8}O{sub 8}(OH){sub 4.42}(SO{sub 4}){sub 1.79,} whereas Fe{sub 8}O{sub 8}(OH){sub 4.36}(SO{sub 4}){sub 1.82} and Fe{sub 8}O{sub 8}(OH){sub 4.29}(SO{sub 4}){sub 1.86} as its chemical formula when the initial pH was 1.80 and 1.60, respectively.

Influence of process variables on biooxidation of ferrous sulfate by an indigenous Acidithiobacillus ferrooxidans. Part I: Flask experiments

Energy Technology Data Exchange (ETDEWEB)

S.M. Mousavi; S. Yaghmaei; F. Salimi; A. Jafari [Sharif University of Technology, Tehran (Iran). Department of Chemical and Petroleum Engineering

2006-12-15

Biological oxidation of ferrous sulfate by Acidithiobacillus ferrooxidans has proved to be a significant step in the bioleaching of sulfide minerals and the treatment of acid mine drainage. The same bioreaction also has beneficial applications in the desulphurization of coal and removal of hydrogen sulfide from gaseous effluents. In this research, the effects of some process variables such as pH, temperature, elemental sulfur, amount of initial ferrous and magnesium ions on oxidation of ferrous sulfate by a native A. ferrooxidans, which was isolated from a chalcopyrite concentrate, were investigated. All experiments carried out in shake flasks at 33{sup o}C that was obtained as optimum temperature for the specific bacterial growth rate. The optimum range of pH for the maximum growth of the cells and effective biooxidation of ferrous sulfate varied from 2 to 2.3. The maximum biooxidation rate was achieved 1.2 g/L h in a culture initially containing 20.2 g/L Fe{sup 2+}. Mg{sup 2+} from 20 mg/L to 120 mg/L did not have any effect on the efficiency of the process, while the presence of elemental sulfur had negative effect on the biooxidation. 16 refs., 8 figs.

The small heat shock proteins from Acidithiobacillus ferrooxidans: gene expression, phylogenetic analysis, and structural modeling

Directory of Open Access Journals (Sweden)

Ribeiro Daniela A

2011-12-01

Full Text Available Abstract Background Acidithiobacillus ferrooxidans is an acidophilic, chemolithoautotrophic bacterium that has been successfully used in metal bioleaching. In this study, an analysis of the A. ferrooxidans ATCC 23270 genome revealed the presence of three sHSP genes, Afe_1009, Afe_1437 and Afe_2172, that encode proteins from the HSP20 family, a class of intracellular multimers that is especially important in extremophile microorganisms. Results The expression of the sHSP genes was investigated in A. ferrooxidans cells submitted to a heat shock at 40°C for 15, 30 and 60 minutes. After 60 minutes, the gene on locus Afe_1437 was about 20-fold more highly expressed than the gene on locus Afe_2172. Bioinformatic and phylogenetic analyses showed that the sHSPs from A. ferrooxidans are possible non-paralogous proteins, and are regulated by the σ32 factor, a common transcription factor of heat shock proteins. Structural studies using homology molecular modeling indicated that the proteins encoded by Afe_1009 and Afe_1437 have a conserved α-crystallin domain and share similar structural features with the sHSP from Methanococcus jannaschii, suggesting that their biological assembly involves 24 molecules and resembles a hollow spherical shell. Conclusion We conclude that the sHSPs encoded by the Afe_1437 and Afe_1009 genes are more likely to act as molecular chaperones in the A. ferrooxidans heat shock response. In addition, the three sHSPs from A. ferrooxidans are not recent paralogs, and the Afe_1437 and Afe_1009 genes could be inherited horizontally by A. ferrooxidans.

Insights into the iron and sulfur energetic metabolism of Acidithiobacillus ferrooxidans by microarray transcriptome profiling

Energy Technology Data Exchange (ETDEWEB)

R. Quatrini; C. Appia-Ayme; Y. Denis; J. Ratouchniak; F. Veloso; J. Valdes; C. Lefimil; S. Silver; F. Roberto; O. Orellana; F. Denizot; E. Jedlicki; D. Holmes; V. Bonnefoy

2006-09-01

Acidithiobacillus ferrooxidans is a well known acidophilic, chemolithoautotrophic, Gram negative, bacterium involved in bioleaching and acid mine drainage. In aerobic conditions, it gains energy mainly from the oxidation of ferrous iron and/or reduced sulfur compounds present in ores. After initial oxidation of the substrate, electrons from ferrous iron or sulfur enter respiratory chains and are transported through several redox proteins to oxygen. However, the oxidation of ferrous iron and reduced sulfur compounds has also to provide electrons for the reduction of NAD(P) that is subsequently required for many metabolic processes including CO2 fixation. To help to unravel the enzymatic pathways and the electron transfer chains involved in these processes, a genome-wide microarray transcript profiling analysis was carried out. Oligonucleotides corresponding to approximately 3000 genes of the A. ferrooxidans type strain ATCC23270 were spotted onto glass-slides and hybridized with cDNA retrotranscribed from RNA extracted from ferrous iron and sulfur grown cells. The genes which are preferentially transcribed in ferrous iron conditions and those preferentially transcribed in sulfur conditions were analyzed. The expression of a substantial number of these genes has been validated by real-time PCR, Northern blot hybridization and/or immunodetection analysis. Our results support and extend certain models of iron and sulfur oxidation and highlight previous observations regarding the possible presence of alternate electron pathways. Our findings also suggest ways in which iron and sulfur oxidation may be co-ordinately regulated. An accompanying paper (Appia-Ayme et al.) describes results pertaining to other metabolic functions.

Tomato Cutin Deficient 1 (CD1) and putative orthologs comprise an ancient family of cutin synthase‐like (CUS) proteins that are conserved among land plants

DEFF Research Database (Denmark)

Yeats, Trevor H.; Huang, Wenlin; Chatterjee, Subhasish

2014-01-01

synthases within the large GDSL superfamily. We demonstrate that members of this ancient and conserved family of cutin synthase‐like (CUS) proteins act as polyester synthases with negligible hydrolytic activity. Moreover, solution‐state NMR analysis indicates that CD1 catalyzes the formation of primarily...... of hydroxyacylglycerol precursors, catalyzed by the GDSL‐motif lipase/hydrolase family protein (GDSL) Cutin Deficient 1 (CD1). Here, we present additional biochemical characterization of CD1 and putative orthologs from Arabidopsis thaliana and the moss Physcomitrella patens, which represent a distinct clade of cutin...... linear cutin oligomeric products in vitro. These results reveal a conserved mechanism of cutin polyester synthesis in land plants, and suggest that elaborations of the linear polymer, such as branching or cross‐linking, may require additional, as yet unknown, factors....

Retención y Penetración en Estacones de Eucalyptus Saligna. Sometidos a Tratamiento con CuSO4 y Sal CCC, en Baño Caliente y frio y Vacio-Presión

Directory of Open Access Journals (Sweden)

Escobar C. Oscar

1987-09-01

Full Text Available Este trabajo describe y da los resultados obtenidos con el pretratamiento de estacones de Eucalyptus saligna a tres soluciones de CUS04 y su posterior tratamiento con sales CCA (OSMOSE K-33. El sulfato de cobre se aplicó por el método de baño caliente y frío, seguido por el proceso de difusión durante una semana; para los anteriores tratamientos se usó madera verde o parcialmente seca al aire; las sales CCA se aplicaron a madera seca por el método de vacío-presión. Una de las razones para llevar a cabo este refuerzo de las sales CCA, es haber encontrado postes de eucalipto severamente atacados por hongos, en especial con pudrición blanda. Los estacones fueron tratados inicialmente con soluciones de sulfato de cobre a 1 %, 2% y 3% de concentración; luego los estacones fueron tratados con una solución de sal CCA al 2.5% de concentración por vacío-presión. Se usaron 40 estacones distribuídos en 4 grupos de 10: tres (3 grupos fueron usados para el tratamiento con las soluciones de CUS04 y solución de CCA; el grupo restante fue tratado con la sal CCA únicamente, el cual fue usado como grupo testigo para fines de comparación en los ensayos de campo (cementerios.

AHL signaling molecules with a large acyl chain enhance biofilm formation on sulfur and metal sulfides by the bioleaching bacterium Acidithiobacillus ferrooxidans.

Science.gov (United States)

González, Alex; Bellenberg, Sören; Mamani, Sigde; Ruiz, Lina; Echeverría, Alex; Soulère, Laurent; Doutheau, Alain; Demergasso, Cecilia; Sand, Wolfgang; Queneau, Yves; Vera, Mario; Guiliani, Nicolas

2013-04-01

Biofilm formation plays a pivotal role in bioleaching activities of bacteria in both industrial and natural environments. Here, by visualizing attached bacterial cells on energetic substrates with different microscopy techniques, we obtained the first direct evidence that it is possible to positively modulate biofilm formation of the extremophilic bacterium Acidithiobacillus ferrooxidans on sulfur and pyrite surfaces by using Quorum Sensing molecules of the N-acylhomoserine lactone type (AHLs). Our results revealed that AHL-signaling molecules with a long acyl chain (12 or 14 carbons) increased the adhesion of A. ferrooxidans cells to these substrates. In addition, Card-Fish experiments demonstrated that C14-AHL improved the adhesion of indigenous A. ferrooxidans cells from a mixed bioleaching community to pyrite. Finally, we demonstrated that this improvement of cell adhesion is correlated with an increased production of extracellular polymeric substances. Our results open up a promising means to develop new strategies for the improvement of bioleaching efficiency and metal recovery, which could also be used to control environmental damage caused by acid mine/rock drainage.

Hydrogen sulfide oxidation in novel Horizontal-Flow Biofilm Reactors dominated by an Acidithiobacillus and a Thiobacillus species.

Science.gov (United States)

Gerrity, S; Kennelly, C; Clifford, E; Collins, G

2016-09-01

Hydrogen Sulfide (H2S) is an odourous, highly toxic gas commonly encountered in various commercial and municipal sectors. Three novel, laboratory-scale, Horizontal-Flow Biofilm Reactors (HFBRs) were tested for the removal of H2S gas from air streams over a 178-day trial at 10°C. Removal rates of up to 15.1 g [H2S] m(-3) h(-1) were achieved, demonstrating the HFBRs as a feasible technology for the treatment of H2S-contaminated airstreams at low temperatures. Bio-oxidation of H2S in the reactors led to the production of H(+) and sulfate (SO(2-)4) ions, resulting in the acidification of the liquid phase. Reduced removal efficiency was observed at loading rates of 15.1 g [H2S] m(-3) h(-1). NaHCO3 addition to the liquid nutrient feed (synthetic wastewater (SWW)) resulted in improved H2S removal. Bacterial diversity, which was investigated by sequencing and fingerprinting 16S rRNA genes, was low, likely due to the harsh conditions prevailing in the systems. The HFBRs were dominated by two species from the genus Acidithiobacillus and Thiobacillus. Nonetheless, there were significant differences in microbial community structure between distinct HFBR zones due to the influence of alkalinity, pH and SO4 concentrations. Despite the low temperature, this study indicates HFBRs have an excellent potential to biologically treat H2S-contaminated airstreams.

A Comparative Study on the Effect of Flotation Reagents on Growth and Iron Oxidation Activities of Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

Mohammad Jafari

2016-12-01

Full Text Available Recently, extraction of metals from different resources using a simple, efficient, and low-cost technique-known as bioleaching-has been widely considered, and has turned out to be an important global technology. Leptospirillum ferrooxidans and Acidithiobacillus (Thiobacillus ferrooxidans are ubiquitous bacteria in the biomining industry. To date, the effects of commercial flotation reagents on the biooxidation activities of these bacteria have not been thoroughly studied. This investigation, by using various systematic measurement methods, studied the effects of various collectors and frothers (collectors: potassium amylxanthate, potassium isobutyl-xanthate, sodium ethylxanthate, potassium isopropylxanthate, and dithiophosphate; and frothers: pine oil and methyl isobutyl carbinol on L. ferrooxidans and A. ferrooxidans activities. In general, results indicate that in the presence of these collectors and frothers, L. ferrooxidans is less sensitive than T. ferrooxidans. In addition, the inhibition effect of collectors on both bacteria is recommended in the following order: for the collectors, potassium isobutyl-xanthate > dithiophosphate > sodium ethylxanthate > potassium isobutyl-xanthate > potassium amylxanthate; and for the frothers, methyl isobutyl carbinol > pine oil. These results can be used for the optimization of biometallurgical processes or in the early stage of a process design for selection of flotation reagents.

Synthesis of argentojarosite with simulated bioleaching solutions produced by Acidithiobacillus ferrooxidans

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, Chiranjit [Department of Microbiology, Ohio State University, 484 West 12" t" h Avenue, Columbus, OH 43210 (United States); Jones, F. Sandy; Bigham, Jerry M. [School of Environment and Natural Resources, Ohio State University, 2021 Coffey Road, Columbus, OH 43210 (United States); Tuovinen, Olli H., E-mail: tuovinen.1@osu.edu [Department of Microbiology, Ohio State University, 484 West 12" t" h Avenue, Columbus, OH 43210 (United States)

2016-09-01

Argentojarosite (AgFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}) is formed as a secondary phase in Ag-catalyzed bioleaching of chalcopyrite (CuFeS{sub 2}), but to date very little is known about the paragenesis or characteristics of this silver-containing compound. The purpose of this study was to synthesize argentojarosite via biological oxidation of 120 mM ferrous sulfate by Acidithiobacillus ferrooxidans. Because of its toxicity to A. ferrooxidans, Ag{sup +} (as AgNO{sub 3}) was added to spent culture media (pH 2) after complete oxidation of ferrous sulfate. Schwertmannite (ideally Fe{sub 8}O{sub 8}(OH){sub 6}(SO{sub 4})) was precipitated during the iron oxidation phase, and subsequent Ag{sup +} addition resulted in the formation of argentojarosite. Contact time (8 h, 5 d, and 14 d) and Ag{sup +} concentration (0, 5, 20, and 40 mM) were used as variables in these experiments. Synthesis of argentojarosite, schwertmannite and other mineral phases was confirmed through X-ray diffraction analysis. Additional analyses of solid-phase oxidation products included elemental composition, color and specific surface area. The sample synthesized in the presence of 40 mM Ag{sup +} and with 14 d contact time yielded an X-ray diffraction pattern of well crystallized argentojarosite, and its elemental composition closely matched the calculated Ag, Fe, and S contents of ideal argentojarosite. The color and surface area of the remaining samples were influenced by the presence of residual schwertmannite. This phase remained stable over the time course of 14 d when no Ag{sup +} was present in the system. When equilibrations were extended to 42 d, partial conversion of reference schwertmannite to goethite was noted in the absence of Ag. In the presence of 20 mM or 40 mM Ag over the same time course, some formation of argentojarosite was also noted. In this case, schwertmannite was the only source of Fe and SO{sub 4} for argentojarosite formation. - Highlights: • Iron-oxidizing bacteria

Synthesis of argentojarosite with simulated bioleaching solutions produced by Acidithiobacillus ferrooxidans

International Nuclear Information System (INIS)

th Avenue, Columbus, OH 43210 (United States))" data-affiliation=" (Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210 (United States))" >Mukherjee, Chiranjit; Jones, F. Sandy; Bigham, Jerry M.; th Avenue, Columbus, OH 43210 (United States))" data-affiliation=" (Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210 (United States))" >Tuovinen, Olli H.

2016-01-01

Argentojarosite (AgFe 3 (SO 4 ) 2 (OH) 6 ) is formed as a secondary phase in Ag-catalyzed bioleaching of chalcopyrite (CuFeS 2 ), but to date very little is known about the paragenesis or characteristics of this silver-containing compound. The purpose of this study was to synthesize argentojarosite via biological oxidation of 120 mM ferrous sulfate by Acidithiobacillus ferrooxidans. Because of its toxicity to A. ferrooxidans, Ag + (as AgNO 3 ) was added to spent culture media (pH 2) after complete oxidation of ferrous sulfate. Schwertmannite (ideally Fe 8 O 8 (OH) 6 (SO 4 )) was precipitated during the iron oxidation phase, and subsequent Ag + addition resulted in the formation of argentojarosite. Contact time (8 h, 5 d, and 14 d) and Ag + concentration (0, 5, 20, and 40 mM) were used as variables in these experiments. Synthesis of argentojarosite, schwertmannite and other mineral phases was confirmed through X-ray diffraction analysis. Additional analyses of solid-phase oxidation products included elemental composition, color and specific surface area. The sample synthesized in the presence of 40 mM Ag + and with 14 d contact time yielded an X-ray diffraction pattern of well crystallized argentojarosite, and its elemental composition closely matched the calculated Ag, Fe, and S contents of ideal argentojarosite. The color and surface area of the remaining samples were influenced by the presence of residual schwertmannite. This phase remained stable over the time course of 14 d when no Ag + was present in the system. When equilibrations were extended to 42 d, partial conversion of reference schwertmannite to goethite was noted in the absence of Ag. In the presence of 20 mM or 40 mM Ag over the same time course, some formation of argentojarosite was also noted. In this case, schwertmannite was the only source of Fe and SO 4 for argentojarosite formation. - Highlights: • Iron-oxidizing bacteria were used to oxidize Fe 2+ in the absence of K + and NH 4 + . �

Immobilization of Acidithiobacillus ferrooxidans on sulfonated microporous poly(styrene-divinylbenzene) copolymer with granulated activated carbon and its use in bio-oxidation of ferrous iron.

Science.gov (United States)

Koseoglu-Imer, Derya Yuksel; Keskinler, Bulent

2013-01-01

The immobilization efficiencies of Acidithiobacillus ferrooxidans cells on different immobilization matrices were investigated for biooxidation of ferrous iron (Fe(2+)) to ferric iron (Fe(3+)). Six different matrices were used such as the polyurethane foam (PUF), granular activated carbon (GAC), raw poly(styrene-divinylbenzene) copolymer (rawSDVB), raw poly(styrene-divinylbenzene) copolymer with granular activated carbon (rawSDVB-GAC), sulfonated poly(styrene-divinylbenzene) copolymer (sulfSDVB) and sulfonated poly(styrene-divinylbenzene) copolymer with granular activated carbon (sulfSDVB-GAC). The sulfSDVB-GAC polymer showed the best performance for Fe(2+) biooxidation. It was used at packed-bed bioreactor and the kinetic parameters were obtained. The highest Fe(2+) biooxidation rate (R) was found to be 4.02 g/L h at the true dilution rate (Dt) of 2.47 1/h and hydraulic retention time (τ) of 0.4 h. The sulfSDVB-GAC polymer was used for the first time as immobilization material for A. ferrooxidans for Fe(2+) biooxidation. Copyright © 2012 Elsevier B.V. All rights reserved.

The environmental context of Acidithiobacillus ferrooxidans and its potential role as an ecosystem engineer in sulphidic mine waste

Energy Technology Data Exchange (ETDEWEB)

Ebenaa, Gustav

2001-06-01

Microorganisms are the causative agent of the environmental problems since they catalyse the weathering of the (sulphidic) waste. The chemical oxidation alone is not fast enough to create any severe environmental problems. Acidithiobacillus ferrooxidans is thought to be a key organism in weathering of sulphide minerals. A. ferrooxidans is affected by several more or less abiotic factors. The influence of temperature, pH and nutrient deficiency as potentially limiting factors for the activity of A. ferrooxidans has been investigated. It seems that temperature has less influence on its activity, but rather reflects the origin of the bacterial isolate. An alkaline pH seems enough to hinder growth and activity. The nutrients do not seem to be a limiting factor in the studied environment. The possible regulation of the activity of A. ferrooxidans is therefore a way to, at least partly, mitigate the environmental impact from mine waste. Waste from the mining industry is the largest waste problem in Sweden. With amounts over 600 million tonnes one could easily imagine the tremendous cost involved in the abatement. The MiMi-programme, with researchers from several relevant fields, has as its aim to evaluate present and to find alternative techniques to mitigate the environmental impact from mine waste. The understanding of A. ferrooxidans and its role as an ecosystem engineer is essential both in evaluating present techniques and even more so in finding alternative abatement techniques for sulphidic mine waste.

ribB and ribBA genes from Acidithiobacillus ferrooxidans: expression levels under different growth conditions and phylogenetic analysis.

Science.gov (United States)

Knegt, Fábio H P; Mello, Luciane V; Reis, Fernanda C; Santos, Marcos T; Vicentini, Renato; Ferraz, Lúcio F C; Ottoboni, Laura M M

2008-01-01

Acidithiobacillus ferrooxidans is a Gram-negative, chemolithoautotrophic bacterium involved in metal bioleaching. Using the RNA arbitrarily primed polymerase chain reaction (RAP-PCR), we have identified several cDNAs that were differentially expressed when A. ferrooxidans LR was submitted to potassium- and phosphate-limiting conditions. One of these cDNAs showed similarity with ribB. An analysis of the A. ferrooxidans ATCC 23270 genome, made available by The Institute for Genomic Research, showed that the ribB gene was not located in the rib operon, but a ribBA gene was present in this operon instead. The ribBA gene was isolated from A. ferrooxidans LR and expression of both ribB and ribBA was investigated. Transcript levels of both genes were enhanced in cells grown in the absence of K2HPO4, in the presence of zinc and copper sulfate and in different pHs. Transcript levels decreased upon exposure to a temperature higher than the ideal 30 degrees C and at pH 1.2. A comparative genomic analysis using the A. ferrooxidans ATCC 23270 genome revealed similar putative regulatory elements for both genes. Moreover, an RFN element was identified upstream from the ribB gene. Phylogenetic analysis of the distribution of RibB and RibBA in bacteria showed six different combinations. We suggest that the presence of duplicated riboflavin synthesis genes in bacteria must provide their host with some benefit in certain stressful situations.

Aspectos moleculares das ataxias espinocerebelares autossomicas recessivas

OpenAIRE

Flavia Chagas Costa

2000-01-01

Resumo: As ataxias espinocerebelares (ABC) formam um grupo heterogêneo de doenças degenerativas que envolvem o sistema nervoso central. Esse grupo se caracteriza clinicamente por apresentar disfunção cerebelar manifestada por ataxia de marcha, incoordenação e disartria. Nos casos familiares, o padrão de herança é variável, podendo ser compatível com herança autossômica dominante (HAD) ou herança autossômica recessiva (HAR). Para as ataxias espinocerebelares com HAR existem três lócus identifi...

Investigation of Acidithiobacillus ferrooxidans in pure and mixed-species culture for bioleaching of Theisen sludge from former copper smelting.

Science.gov (United States)

Klink, C; Eisen, S; Daus, B; Heim, J; Schlömann, M; Schopf, S

2016-06-01

The aim of this study was to investigate the potential of bioleaching for the treatment of an environmentally hazardous waste, a blast-furnace flue dust designated Theisen sludge. Bioleaching of Theisen sludge was investigated at acidic conditions with Acidithiobacillus ferrooxidans in pure and mixed-species culture with Acidiphilium. In shaking-flask experiments, bioleaching parameters (pH, redox potential, zinc extraction from ZnS, ferrous- and ferric-iron concentration) were controlled regularly. The analysis of the dissolved metals showed that 70% zinc and 45% copper were extracted. Investigations regarding the arsenic and antimony species were performed. When iron ions were lacking, animonate (Sb(V)) and total arsenic concentration were highest in solution. The bioleaching approach was scaled up in stirred-tank bioreactors resulting in higher leaching efficiency of valuable trace elements. Concentrations of dissolved antimony were approx. 23 times, and of cobalt, germanium, and rhenium three times higher in comparison to shaking-flask experiments, when considering the difference in solid load of Theisen sludge. The extraction of base and trace metals from Theisen sludge, despite of its high content of heavy metals and organic compounds, was feasible with iron-oxidizing acidophilic bacteria. In stirred-tank bioreactors, the mixed-species culture performed better. To the best of our knowledge, this study is the first providing an appropriate biological technology for the treatment of Theisen sludge to win valuable elements. © 2016 The Society for Applied Microbiology.

Transformações espaciais na zona costeira : um estudo das relações entre economia, turismo e urbanização no Brasil, Espanha e Marrocos

OpenAIRE

Andréa Máximo Espínola

2013-01-01

Esta tese investiga a correlação entre os ciclos econômicos, os ciclos urbanos e os ciclos turísticos. O litoral foi escolhido como lócus de investigação por apresentar especificidades em sua trajetória econômica e urbana e três estudos de caso foram analisados: Brasil, Espanha e Marrocos. Para abordar o tema proposto optou-se por uma análise baseada em teorias que tratam o ambiente construído como elemento central da dinâmica do capitalismo associados a constante criação de novas localidades...

Preparation and characterization of nanocomposite between poly(aniline-co-m-chloroaniline)–copper sulfide nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Abbas, Saeed J.; Rani, Mamta; Tripathi, S.K., E-mail: surya@pu.ac.in

2014-06-15

One dimensional nanostructures of poly(aniline-co-m-chloroaniline) nanocomposite (NC) with CuS nanoparticles (NPs) are prepared by template free method. CuS NPs are prepared by chemical method by using trisodium nitilotriacetate acid as a complexing agent. The materials are characterized by X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Ultraviolet spectroscopy (UV-Vis), photoluminescence (PL) spectroscopy and thermogravimetric analysis (TGA). The hexagonal structure of CuS NPs is confirmed from XRD results with lattice parameters, a=3.78 Å and c=16.288 Å. The diameter of CuS NPs is found to be 16 nm from TEM measurements. Different shapes such as NPs, nanorods and nanotubes structures are observed for poly(aniline-co-m-chloroaniline) whereas its NC with CuS NPs have nanorod and nanotube shapes. Significant shift in the absorption edge of CuS NC is observed in comparison with copolymer and CuS NPs. Also the thermal stability of CuS NC is improved as compared with a copolymer and CuS NPs.

Improved performance of CdSe/CdS co-sensitized solar cells adopting efficient CuS counter electrode modified by PbS film using SILAR method

Science.gov (United States)

Zhang, Xiaolong; Lin, Yu; Wu, Jihuai; Fang, Biaopeng; Zeng, Jiali

2018-04-01

In this paper, CuS film was deposited onto fluorine-doped tin oxide (FTO) substrate using a facile chemical bath deposition method, and then modified by PbS using simple successive ionic layer absorption and reaction (SILAR) method with different cycles. These CuS/PbS films were utilized as counter electrodes (CEs) for CdSe/CdS co-sensitized solar cells. Field-emission scanning electron microscopy equipped with an energy-dispersive X-ray spectrometer was used to characterize the CuS/PbS films. The results show that CuS/PbS (10 cycles) CE exhibits an improved power conversion efficiency of 5.54% under the illumination of one sun (100 mW cm-2), which is higher than the CuS/PbS (0 cycles), CuS/PbS (5 cycles), and CuS/PbS (15 cycles) CEs. This enhancement is mainly attributed to good catalytic activity and lower charge-transfer and series resistances, which have been proved by electrochemical impedance spectroscopy, and Tafel polarization measurements.

Insights on the structure and stability of Licanantase: a trimeric acid-stable coiled-coil lipoprotein from Acidithiobacillus thiooxidans

Directory of Open Access Journals (Sweden)

Fernando Abarca

2014-08-01

Full Text Available Licanantase (Lic is the major component of the secretome of Acidithiobacillus thiooxidans when grown in elemental sulphur. When used as an additive, Lic improves copper recovery from bioleaching processes. However, this recovery enhancement is not fully understood. In this context, our aim is to predict the 3D structure of Lic, to shed light on its structure-function relationships. Bioinformatics analyses on the amino acid sequence of Lic showed a great similarity with Lpp, an Escherichia coli Lipoprotein that can form stable trimers in solution. Lic and Lpp share the secretion motif, intracellular processing and alpha helix structure, as well as the distribution of hydrophobic residues in heptads forming a hydrophobic core, typical of coiled-coil structures. Cross-linking experiments showed the presence of Lic trimers, supporting our predictions. Taking the in vitro and in silico evidence as a whole, we propose that the most probable structure for Lic is a trimeric coiled-coil. According to this prediction, a suitable model for Lic was produced using the de novo algorithm “Rosetta Fold-and-Dock”. To assess the structural stability of our model, Molecular Dynamics (MD and Replica Exchange MD simulations were performed using the structure of Lpp and a 14-alanine Lpp mutant as controls, at both acidic and neutral pH. Our results suggest that Lic was the most stable structure among the studied proteins in both pH conditions. This increased stability can be explained by a higher number of both intermonomer hydrophobic contacts and hydrogen bonds, key elements for the stability of Lic’s secondary and tertiary structure.

Emergency medicine point-of-care ultrasonography: a national needs assessment of competencies for general and expert practice.

Science.gov (United States)

Fischer, Lisa M; Woo, Michael Y; Lee, A Curtis; Wiss, Ray; Socransky, Steve; Frank, Jason R

2015-01-01

Emergency medicine point-of-care ultrasonography (EM-PoCUS) is a core competency for residents in the Royal College of Physicians and Surgeons of Canada and College of Family Physicians of Canada emergency medicine (EM) training programs. Although EM-PoCUS fellowships are currently offered in Canada, there is little consensus regarding what training should be included in a Canadian EM-PoCUS fellowship curriculum or how this contrasts with the training received in an EM residency.Objectives To conduct a systematic needs assessment of major stakeholders to define the essential elements necessary for a Canadian EM-PoCUS fellowship training curriculum. We carried out a national survey of experts in EM-PoCUS, EM residency program directors, and EM residents. Respondents were asked to identify competencies deemed either nonessential to EM practice, essential for general EM practice, essential for advanced EM practice, or essential for EM-PoCUS fellowship trained (‘‘expert’’) practice. The response rate was 81% (351 of 435). PoCUS was deemed essential to general EM practice for basic cardiac, aortic, trauma, and procedural imaging. PoCUS was deemed essential to advanced EM practice in undifferentiated symptomatology, advanced chest pathologies, and advanced procedural applications. Expert-level PoCUS competencies were identified for administrative, pediatric, and advanced gynecologic applications. Eighty-seven percent of respondents indicated that there was a need for EM-PoCUS fellowships, with an ideal length of 6 months. This is the first needs assessment of major stakeholders in Canada to identify competencies for expert training in EM-PoCUS. The competencies should form the basis for EM-PoCUS fellowship programs in Canada.

Synthesis and Biomedical Applications of Copper Sulfide Nanoparticles: From Sensors to Theranostics

Science.gov (United States)

Goel, Shreya; Chen, Feng; Cai, Weibo

2013-01-01

Copper sulfide (CuS) nanoparticles have attracted increasing attention from biomedical researchers across the globe, because of their intriguing properties which have been mainly explored for energy- and catalysis-related applications to date. This focused review article aims to summarize the recent progress made in the synthesis and biomedical applications of various CuS nanoparticles. After a brief introduction to CuS nanoparticles in the first section, we will provide a concise outline of the various synthetic routes to obtain different morphologies of CuS nanoparticles, which can influence their properties and potential applications. CuS nanoparticles have found broad applications in vitro, especially in the detection of biomolecules, chemicals, and pathogens which will be illustrated in detail. The in vivo uses of CuS nanoparticles have also been investigated in preclinical studies, including molecular imaging with various techniques, cancer therapy based on the photothermal properties of CuS, as well as drug delivery and theranostic applications. Research on CuS nanoparticles will continue to thrive over the next decade, and tremendous opportunities lie ahead for potential biomedical/clinical applications of CuS nanoparticles. PMID:24106015

Portable exhausters POR-004 SKID B, POR-005 SKID C, POR-006 SKID D storage plan

International Nuclear Information System (INIS)

Nelson, O.D.; Keller, G.M.

1997-01-01

This document provides a storage plan for portable exhausters POR-004 SKID B, POR-005 SKID C, AND POR-006 SKID D. The exhausters will be stored until they are needed by the TWRS (Tank Waste Remediation Systems) Saltwell Pumping Program. The storage plan provides criteria for portable exhauster storage, periodic inspections during storage, and retrieval from storage

Effects of Arsenite Resistance on the Growth and Functional Gene Expression of Leptospirillum ferriphilum and Acidithiobacillus thiooxidans in Pure Culture and Coculture

Directory of Open Access Journals (Sweden)

Huidan Jiang

2015-01-01

Full Text Available The response of iron-oxidizing Leptospirillum ferriphilum YSK and sulfur-oxidizing Acidithiobacillus thiooxidans A01 to arsenite under pure culture and coculture was investigated based on biochemical characterization (concentration of iron ion and pH value and related gene expression. L. ferriphilum YSK and At. thiooxidans A01 in pure culture could adapt up to 400 mM and 800 mM As(III after domestication, respectively, although arsenite showed a negative effect on both strains. The coculture showed a stronger sulfur and ferrous ion oxidation activity when exposed to arsenite. In coculture, the pH value showed no significant difference when under 500 mM arsenite stress, and the cell number of At. thiooxidans was higher than that in pure culture benefiting from the interaction with L. ferriphilum. The expression profile showed that the arsenic efflux system in the coculture was more active than that in pure culture, indicating that there is a synergetic interaction between At. thiooxidans A01 and L. ferriphilum YSK. In addition, a model was proposed to illustrate the interaction between arsenite and the ars operon in L. ferriphilum YSK and At. thiooxidans A01. This study will facilitate the effective application of coculture in the bioleaching process by taking advantage of strain-strain communication and coordination.

Comparing brain white matter on sequential cranial ultrasound and MRI in very preterm infants

Energy Technology Data Exchange (ETDEWEB)

Leijser, Lara M.; Veen, Sylvia; Boer, Inge P. de; Walther, Frans J.; Wezel-Meijler, Gerda van [Leiden University Medical Center, Department of Pediatrics, Division of Neonatology, Albinusdreef 2, P.O. Box 9600, Leiden (Netherlands); Liauw, Lishya [Leiden University Medical Center, Department of Radiology, Division of Neuroradiology, Albinusdreef 2, P.O. Box 9600, Leiden (Netherlands)

2008-09-15

Periventricular white matter (WM) echodensities, frequently seen in preterm infants, can be associated with suboptimal neurodevelopment. Major WM injury is well detected on cranial ultrasound (cUS). cUS seems less sensitive for diffuse or more subtle WM injury. Our aim was to assess the value of cUS and magnetic resonance imaging (MRI) for evaluating WM changes and the predictive value of cUS and/or MRI findings for neurodevelopmental outcome in very preterm infants with normal to severely abnormal WM on sequential high-quality cUS. Very preterm infants (<32 weeks) who had sequential cUS and one MRI within the first three postnatal months were included. Periventricular WM on cUS and MRI was compared and correlated with neurodevelopmental outcome at 2 years corrected age. Forty preterm infants were studied; outcome data were available in 32. WM changes on sequential cUS were predictive of WM changes on MRI. Severely abnormal WM on cUS/MRI was predictive of adverse outcome, and normal-mildly abnormal WM of favorable outcome. Moderately abnormal WM on cUS/MRI was associated with variable outcome. Additional MRI slightly increased the predictive value of cUS in severe WM changes. Sequential cUS in preterm infants is reliable for detecting WM changes and predicting favorable and severely abnormal outcome. Conventional and diffusion-weighted MRI sequences before term equivalent age in very preterm infants, suggested on cUS to have mild to moderately abnormal WM, do not seem to be warranted. (orig.)

Comparing brain white matter on sequential cranial ultrasound and MRI in very preterm infants

International Nuclear Information System (INIS)

Leijser, Lara M.; Veen, Sylvia; Boer, Inge P. de; Walther, Frans J.; Wezel-Meijler, Gerda van; Liauw, Lishya

2008-01-01

Periventricular white matter (WM) echodensities, frequently seen in preterm infants, can be associated with suboptimal neurodevelopment. Major WM injury is well detected on cranial ultrasound (cUS). cUS seems less sensitive for diffuse or more subtle WM injury. Our aim was to assess the value of cUS and magnetic resonance imaging (MRI) for evaluating WM changes and the predictive value of cUS and/or MRI findings for neurodevelopmental outcome in very preterm infants with normal to severely abnormal WM on sequential high-quality cUS. Very preterm infants (<32 weeks) who had sequential cUS and one MRI within the first three postnatal months were included. Periventricular WM on cUS and MRI was compared and correlated with neurodevelopmental outcome at 2 years corrected age. Forty preterm infants were studied; outcome data were available in 32. WM changes on sequential cUS were predictive of WM changes on MRI. Severely abnormal WM on cUS/MRI was predictive of adverse outcome, and normal-mildly abnormal WM of favorable outcome. Moderately abnormal WM on cUS/MRI was associated with variable outcome. Additional MRI slightly increased the predictive value of cUS in severe WM changes. Sequential cUS in preterm infants is reliable for detecting WM changes and predicting favorable and severely abnormal outcome. Conventional and diffusion-weighted MRI sequences before term equivalent age in very preterm infants, suggested on cUS to have mild to moderately abnormal WM, do not seem to be warranted. (orig.)

Feasibility of emergency department point-of-care ultrasound for rib fracture diagnosis in minor thoracic injury.

Science.gov (United States)

Lalande, Élizabeth; Guimont, Chantal; Émond, Marcel; Parent, Marc Charles; Topping, Claude; Kuimi, Brice Lionel Batomen; Boucher, Valérie; Le Sage, Natalie

2017-05-01

The main objective of this study was to evaluate the feasibility of emergency department (ED) point-of-care ultrasound (PoCUS) for rib fracture diagnosis in patients with minor thoracic injury (mTI). Secondary objectives were to 1) evaluate patients' pain during the PoCUS procedure, 2) identify the limitations of the use of PoCUS technique, and 3) compare the diagnosis obtained with PoCUS to radiography results. Adult patients who presented with clinical suspicion of rib fractures after mTI were included. All patients underwent PoCUS performed by emergency physicians (EPs) prior to a rib view X-ray. A visual analogue scale (VAS) ranging from 0 to 100 was used to ascertain feasibility, patients' pain and clinicians' degree of certitude. Feasibility was defined as a score of more than 50 on the VAS. We documented the radiologists' interpretation of rib view X-ray. Radiologists were blinded to the PoCUS results. Ninety-six patients were included. A majority (65%) of EPs concluded that the PoCUS technique to diagnose rib fracture was feasible (VAS score > 50). Median score for feasibility was 63. Median score was 31 (Interquartile range [IQR] 5-57) for patients' pain related to the PoCUS. The main limiting factor of the PoCUS technique was pain during patient examination (15%). PoCUS examination appears to be a feasible technique for a rib fracture diagnosis in the ED.

[Effects of cucurmosin on the cell proliferation and apoptosis in human pancreatic PANC-1 cells].

Science.gov (United States)

Xu, Chun-Sen; Huang, He-Guang; Chen, Ming-Huang

2012-02-01

To observe the effects of cucurmosin (CUS) on the cell proliferation and apoptosis in pancreatic PANC-1 cells. The inhibition of CUS on the PANC-1 cell growth was observed using MTT assay. The inhibition ratio of CUS on the pancreatic orthotopic transplantation was in vivo observed in the NOD/SCID mouse model. The changes of microstructure of the apoptosis-inducing effect of CUS on PANC-1 was observed under electron microscope. The cell cycle and apoptosis after CUS intervention was detected using flow cytometry. The Caspase-3 activity after CUS treatment was detected using enzyme linked immunospecific assay (ELISA). Treatment with CUS at the dose of 0.125, 0.25, and 0.5 mg/kg inhibited the growth of pancreatic carcinoma PANC-1 xenografs with the ratio of 45.2%, 50.0%, and 59.7%, respectively (P PANC-1 cells in a dose-dependent maner. Being exposed to 40.0 microg/mL of the CUS for 24, 48, and 72 h, the percentage of G0/ G1 phase cells was 56.60% +/- 6.65%, 67.83% +/- 6.76%, and 77.00% +/- 6.73%, respectively (P PANC-1 cells in the G0/G1 phase of the cell cycle in a time-dependent maner. CUS significantly inhibited the growth of PANC-1 cells possibly through the G0/G1 cell cycle arrest and apoptosis.

Is sequential cranial ultrasound reliable for detection of white matter injury in very preterm infants?

International Nuclear Information System (INIS)

Leijser, Lara M.; Steggerda, Sylke J.; Walther, Frans J.; Wezel-Meijler, Gerda van; Bruine, Francisca T. de; Grond, Jeroen van der

2010-01-01

Cranial ultrasound (cUS) may not be reliable for detection of diffuse white matter (WM) injury. Our aim was to assess in very preterm infants the reliability of a classification system for WM injury on sequential cUS throughout the neonatal period, using magnetic resonance imaging (MRI) as reference standard. In 110 very preterm infants (gestational age <32 weeks), serial cUS during admission (median 8, range 4-22) and again around term equivalent age (TEA) and a single MRI around TEA were performed. cUS during admission were assessed for presence of WM changes, and contemporaneous cUS and MRI around TEA additionally for abnormality of lateral ventricles. Sequential cUS (from birth up to TEA) and MRI were classified as normal/mildly abnormal, moderately abnormal, or severely abnormal, based on a combination of findings of the WM and lateral ventricles. Predictive values of the cUS classification were calculated. Sequential cUS were classified as normal/mildly abnormal, moderately abnormal, and severely abnormal in, respectively, 22%, 65%, and 13% of infants and MRI in, respectively, 30%, 52%, and 18%. The positive predictive value of the cUS classification for the MRI classification was high for severely abnormal WM (0.79) but lower for normal/mildly abnormal (0.67) and moderately abnormal (0.64) WM. Sequential cUS during the neonatal period detects severely abnormal WM in very preterm infants but is less reliable for mildly and moderately abnormal WM. MRI around TEA seems needed to reliably detect WM injury in very preterm infants. (orig.)

Sequential cranial ultrasound and cerebellar diffusion weighted imaging contribute to the early prognosis of neurodevelopmental outcome in preterm infants.

Directory of Open Access Journals (Sweden)

Margaretha J Brouwer

Full Text Available OBJECTIVE: To evaluate the contribution of sequential cranial ultrasound (cUS and term-equivalent age magnetic resonance imaging (TEA-MRI including diffusion weighted imaging (DWI to the early prognosis of neurodevelopmental outcome in a cohort of very preterm infants (gestational age [GA] <31 weeks. STUDY DESIGN: In total, 93 preterm infants (median [range] GA in weeks: 28.3 [25.0-30.9] were enrolled in this prospective cohort study and underwent early and term cUS as well as TEA-MRI including DWI. Early cUS abnormalities were classified as normal, mild, moderate or severe. Term cUS was evaluated for ex-vacuo ventriculomegaly (VM and enlargement of the extracerebral cerebrospinal fluid (eCSF space. Abnormalities on T1- and T2-weighted TEA-MRI were scored according to Kidokoro et al. Using DWI at TEA, apparent diffusion coefficients (ADCs were measured in four white matter regions bilaterally and both cerebellar hemispheres. Neurodevelopmental outcome was assessed at two years' corrected age (CA using the Bayley Scales of Infant and Toddler Development, third edition. Linear regression analysis was conducted to explore the correlation between the different neuroimaging modalities and outcome. RESULTS: Moderate/severe abnormalities on early cUS, ex-vacuo VM and enlargement of the eCSF space on term cUS and increased cerebellar ADC values on term DWI were independently associated with worse motor outcome (p<.05. Ex-vacuo VM on term cUS was also related to worse cognitive performance at two years' CA (p<.01. CONCLUSION: These data support the clinical value of sequential cUS and recommend repeating cUS at TEA. In particular, assessment of moderate/severe early cUS abnormalities and ex-vacuo VM on term cUS provides important prognostic information. Cerebellar ADC values may further aid in the prognostication of gross motor function.

Celulitis por citomegalovirus

Directory of Open Access Journals (Sweden)

A. Ruiz Lascano

2002-12-01

Full Text Available Las lesiones cutáneas por citomegalovirus (CMV son infrecuentes y a menudo una manifestación tardía de una enfermedad sistémica, que generalmente anuncia un curso fatal. Comunicamos un caso de celulitis por CMV: una mujer de 70 años con trasplante renal efectuado 1 mes antes de la consulta, terapia inmunosupresora con ciclosporina A y metilprednisona. La paciente ingresó por fiebre, dolor e impotencia funcional en pierna derecha. Comprobamos la existencia de una placa de 8 por 4 cm eritematoedematosa. La tratamos con antibióticos sin mejoría, por lo que realizamos un estudio histopatológico de piel que mostró cambios citopáticos compatibles con infección por CMV. Los cultivos bacteriológicos y micológicos fueron negativos. La inmunohistoquímica específica para CMV y el estudio de reacción en cadena de la polimerasa (PCR de la biopsia de piel fueron positivas, al igual que la antigenemia. El tratamiento con ganciclovir produjo la mejoría del cuadro clínico. En la literatura revisada no hemos encontrado la celulitis como manifestación de enfermedad cutánea por CMV.

Posterior fossa abnormalities in high-risk term infants: comparison of ultrasound and MRI

Energy Technology Data Exchange (ETDEWEB)

Steggerda, S.J.; Smits-Wintjens, V.E.H.J.; Verbon, P.; Walther, F.J. [Leiden University Medical Centre, Department of Neonatology, Leiden (Netherlands); Bruine, F.T. de [Leiden University Medical Centre, Department of Radiology, Leiden (Netherlands); Wezel-Meijler, G. van [Leiden University Medical Centre, Department of Radiology, Leiden (Netherlands); Isala Hospital, Department of Neonatology, Zwolle (Netherlands)

2015-09-15

We aimed to assess the characteristics of posterior fossa (PF) abnormalities in a cohort of high-risk term neonates, as well as the diagnostic performance of cranial ultrasound (CUS) with additional mastoid fontanelle (MF) views for the detection of these abnormalities, with magnetic resonance imaging (MRI) being the reference standard. In this retrospective study, 113 term neonates with CUS and subsequent MRI were included. Sensitivity, specificity, and predictive values of routine CUS and CUS with MF views were calculated. Posterior fossa abnormalities were diagnosed on CUS in 46 of 113 infants. MRI confirmed these findings in 43 and showed additional abnormalities in 32 infants. The sensitivity and specificity of anterior fontanelle views for major PF abnormalities as seen on MRI were 16 % and 99 %. Adding MF views increased the sensitivity of US to 82 %. The sensitivity and specificity of MF views for the detection of any (major or minor) PF abnormality were 57 % and 95 %. Especially acute hypoxic-ischemic injury and small subdural and punctate cerebellar haemorrhage remained undetected by CUS. PF abnormalities are frequent in high-risk term infants. MF-CUS enables early diagnosis of major PF abnormalities. We therefore advocate to perform MF-CUS in high-risk term neonates. (orig.)

Posterior fossa abnormalities in high-risk term infants: comparison of ultrasound and MRI

International Nuclear Information System (INIS)

Steggerda, S.J.; Smits-Wintjens, V.E.H.J.; Verbon, P.; Walther, F.J.; Bruine, F.T. de; Wezel-Meijler, G. van

2015-01-01

We aimed to assess the characteristics of posterior fossa (PF) abnormalities in a cohort of high-risk term neonates, as well as the diagnostic performance of cranial ultrasound (CUS) with additional mastoid fontanelle (MF) views for the detection of these abnormalities, with magnetic resonance imaging (MRI) being the reference standard. In this retrospective study, 113 term neonates with CUS and subsequent MRI were included. Sensitivity, specificity, and predictive values of routine CUS and CUS with MF views were calculated. Posterior fossa abnormalities were diagnosed on CUS in 46 of 113 infants. MRI confirmed these findings in 43 and showed additional abnormalities in 32 infants. The sensitivity and specificity of anterior fontanelle views for major PF abnormalities as seen on MRI were 16 % and 99 %. Adding MF views increased the sensitivity of US to 82 %. The sensitivity and specificity of MF views for the detection of any (major or minor) PF abnormality were 57 % and 95 %. Especially acute hypoxic-ischemic injury and small subdural and punctate cerebellar haemorrhage remained undetected by CUS. PF abnormalities are frequent in high-risk term infants. MF-CUS enables early diagnosis of major PF abnormalities. We therefore advocate to perform MF-CUS in high-risk term neonates. (orig.)

Novel recombinant immunotoxin of EGFR specific nanobody fused with cucurmosin, construction and antitumor efficiency in vitro.

Science.gov (United States)

Deng, Cuimin; Xiong, Jiani; Gu, Xiaofan; Chen, Xiaoying; Wu, Shuifa; Wang, Zhe; Wang, Duanduan; Tu, Jinjin; Xie, Jieming

2017-06-13

Epidermal growth factor receptor (EGFR) overexpression is related to the increased aggressiveness, metastases, and poor prognosis in various cancers. In this study, we successfully constructed a new EGFR nanobody-based immunotoxin rE/CUS containing cucurmosin (CUS), The immunotoxin was expressed by prokaryotic system and we obtained a yield of 5 mg protein per liter expression medium. The percentage of it's binding ability totumor cell lines A549, HepG2, SW116, which highly expressed EGFR was 55.6%, 79.6% and 97.1%, respectively, but SW620 was only 4.45%. rE/CUS has the ability to bind A549, HepG2, SW116 cells specifically, and the antigen binding capability was not affected because of extra part of CUS component. The rE/CUS significantly inhibited the cell viability against EGFR over expression tumor cell lines in a dose-and time-dependent manner. Moreover, rE/CUS also induced apoptosis of HepG2 and A549 mightily. Our results demonstrate that rE/CUS is a potential therapeutic strategy for treating EGFR-positive solid tumors.

Acidithiobacillus caldus sulfur oxidation model based on transcriptome analysis between the wild type and sulfur oxygenase reductase defective mutant.

Directory of Open Access Journals (Sweden)

Linxu Chen

Full Text Available Acidithiobacillus caldus (A. caldus is widely used in bio-leaching. It gains energy and electrons from oxidation of elemental sulfur and reduced inorganic sulfur compounds (RISCs for carbon dioxide fixation and growth. Genomic analyses suggest that its sulfur oxidation system involves a truncated sulfur oxidation (Sox system (omitting SoxCD, non-Sox sulfur oxidation system similar to the sulfur oxidation in A. ferrooxidans, and sulfur oxygenase reductase (SOR. The complexity of the sulfur oxidation system of A. caldus generates a big obstacle on the research of its sulfur oxidation mechanism. However, the development of genetic manipulation method for A. caldus in recent years provides powerful tools for constructing genetic mutants to study the sulfur oxidation system.An A. caldus mutant lacking the sulfur oxygenase reductase gene (sor was created and its growth abilities were measured in media using elemental sulfur (S(0 and tetrathionate (K(2S(4O(6 as the substrates, respectively. Then, comparative transcriptome analysis (microarrays and real-time quantitative PCR of the wild type and the Δsor mutant in S(0 and K(2S(4O(6 media were employed to detect the differentially expressed genes involved in sulfur oxidation. SOR was concluded to oxidize the cytoplasmic elemental sulfur, but could not couple the sulfur oxidation with the electron transfer chain or substrate-level phosphorylation. Other elemental sulfur oxidation pathways including sulfur diooxygenase (SDO and heterodisulfide reductase (HDR, the truncated Sox pathway, and the S(4I pathway for hydrolysis of tetrathionate and oxidation of thiosulfate in A. caldus are proposed according to expression patterns of sulfur oxidation genes and growth abilities of the wild type and the mutant in different substrates media.An integrated sulfur oxidation model with various sulfur oxidation pathways of A. caldus is proposed and the features of this model are summarized.

Generation of acid mine drainage around the Karaerik copper mine (Espiye, Giresun, NE Turkey): implications from the bacterial population in the Acısu effluent.

Science.gov (United States)

Sağlam, Emine Selva; Akçay, Miğraç; Çolak, Dilşat Nigar; İnan Bektaş, Kadriye; Beldüz, Ali Osman

2016-09-01

The Karaerik Cu mine is a worked-out deposit with large volumes of tailings and slags which were left around the mine site without any protection. Natural feeding of these material and run-off water from the mineralised zones into the Acısu effluent causes a serious environmental degradation and creation of acid mine drainage (AMD) along its entire length. This research aims at modelling the formation of AMD with a specific attempt on the characterisation of the bacterial population in association with AMD and their role on its occurrence. Based on 16SrRNA analyses of the clones obtained from a composite water sample, the bacterial community was determined to consist of Acidithiobacillus ferrivorans, Ferrovum myxofaciens, Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans as iron-oxidising bacteria, Acidocella facilis, Acidocella aluminiidurans, Acidiphilium cryptum and Acidiphilium multivorum as iron-reducing bacteria, and Acidithiobacillus ferrivorans, Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans and Acidiphilium cryptum as sulphur-oxidising bacteria. This association of bacteria with varying roles was interpreted as evidence of a concomitant occurrence of sulphur and iron cycles during the generation of AMD along the Acısu effluent draining the Karaerik mine.

Reduction of arsenic content in a complex galena concentrate by Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

López Alejandro

2004-10-01

Full Text Available Abstract Background Bioleaching is a process that has been used in the past in mineral pretreatment of refractory sulfides, mainly in the gold, copper and uranium benefit. This technology has been proved to be cheaper, more efficient and environmentally friendly than roasting and high pressure moisture heating processes. So far the most studied microorganism in bioleaching is Acidithiobacillus ferrooxidans. There are a few studies about the benefit of metals of low value through bioleaching. From all of these, there are almost no studies dealing with complex minerals containing arsenopyrite (FeAsS. Reduction and/or elimination of arsenic in these ores increase their value and allows the exploitation of a vast variety of minerals that today are being underexploited. Results Arsenopyrite was totally oxidized. The sum of arsenic remaining in solution and removed by sampling represents from 22 to 33% in weight (yield of the original content in the mineral. The rest of the biooxidized arsenic form amorphous compounds that precipitate. Galena (PbS was totally oxidized too, anglesite (PbSO4 formed is virtually insoluble and remains in the solids. The influence of seven factors in a batch process was studied. The maximum rate of arsenic dissolution in the concentrate was found using the following levels of factors: small surface area of particle exposure, low pulp density, injecting air and adding 9 K medium to the system. It was also found that ferric chloride and carbon dioxide decreased the arsenic dissolution rate. Bioleaching kinetic data of arsenic solubilization were used to estimate the dilution rate for a continuous culture. Calculated dilution rates were relatively small (0.088–0.103 day-1. Conclusion Proper conditions of solubilization of arsenic during bioleaching are key features to improve the percentage (22 to 33% in weight of arsenic removal. Further studies are needed to determine other factors that influence specifically the

Portable exhauster POR-007/Skid E and POR-008/Skid F storage plan

International Nuclear Information System (INIS)

Nelson, O.D.

1998-01-01

This document provides storage requirements for 1,000 CFM portable exhausters POR-O07/Skid E and POR-008/Skid F. These requirements are presented in three parts: preparation for storage, storage maintenance and testing, and retrieval from storage. The exhauster component identification numbers listed in this document contain the prefix POR-007 or POR-008 depending on which exhauster is being used

Impact of point-of-care ultrasound on clinical decision-making at an urban emergency department in Tanzania.

Science.gov (United States)

Reynolds, Teri Ann; Amato, Stas; Kulola, Irene; Chen, Chuan-Jay Jeffrey; Mfinanga, Juma; Sawe, Hendry Robert

2018-01-01

Point of care ultrasound (PoCUS) is an efficient, inexpensive, safe, and portable imaging modality that can be particularly useful in resource-limited settings. However, its impact on clinical decision making in such settings has not been well studied. The objective of this study is to describe the utilization and impact of PoCUS on clinical decision making at an urban emergency department in Dar es Salaam, Tanzania. This was a prospective descriptive cross-sectional study of patients receiving PoCUS at Muhimbili National Hospital's Emergency Medical Department (MNH EMD). Data on PoCUS studies during a period of 10 months at MNH EMD was collected on consecutive patients during periods when research assistants were available. Data collected included patient age and sex, indications for ultrasound, findings, interpretations, and provider-reported diagnostic impression and disposition plan before and after PoCUS. Descriptive statistics, including medians and interquartile ranges, and counts and percentages, are reported. Pearson chi squared tests and p-values were used to evaluate categorical data for significant differences. PoCUS data was collected for 986 studies performed on 784 patients. Median patient age was 32 years; 56% of patients were male. Top indications for PoCUS included trauma, respiratory presentations, and abdomino-pelvic pain. The most frequent study types performed were eFAST, cardiac, and obstetric or gynaecologic studies. Overall, clinicians reported that the use of PoCUS changed either diagnostic impression or disposition plan in 29% of all cases. Rates of change in diagnostic impression or disposition plan increased to 45% in patients for whom more than one PoCUS study type was performed. In resource-limited emergency care settings, PoCUS can be utilized for a wide range of indications and has substantial impact on clinical decision making, especially when more than one study type is performed.

“SANTAS CRUZES” LOCUS DE NUCLEAÇÃO DE RESTAURAÇÃO AMBIENTAL. METODOLOGIA POR ABANDONO E REGENERAÇÃO ESPONTÂNEA, UM RISCO PARA O BIOMA MATA ATLÂNTICA

Directory of Open Access Journals (Sweden)

Cristiane da Silva Jacob

2017-04-01

Full Text Available Uma expressão cultural-religiosa “Santa Cruz” (altar com descarte de imagens de valor sacro para a Igreja Católica tem possível valor deletério sobre o Hotspot ambiental Mata Atlântica, na região Metropolitana do Vale do Paraíba e Litoral Norte Paulista. Material e Métodos: foi construído um modelo de Santa Cruz similar às encontradas na Mata Atlântica e, durante seis meses (outono/inverno foram medidas as alterações de pH do solo e a retenção de água, pós chuva e em período de seca, pelas imagens de gesso. Os resultados mostraram que nesses lócus o pH do solo oscilou entre 6,3 e 7,0; a umidade retida nas peças de gesso aumentou a massa das imagens em ambos os períodos.Concluiu-se que estas Santas Cruzes podem se transformar em ambientes semelhantes ao modelo de nucleação por abandono usado para a recomposição florestal de áreas degradados, mas também permite o desenvolvimento de Espécies Invasoras ao Bioma, oferecendo riscos antrópicos ao Hotspot.

Optimized animal model to mimic the reality of stress-induced depression in the clinic.

Science.gov (United States)

Zhang, Yi; Wang, Yuting; Lei, Hui; Wang, Lei; Xue, Liang; Wang, Xin; Zhu, Xiongzhao

2017-05-06

Animal models are useful tools for verifying the relationship between stress and depression; however, an operational criterion for excluding the resilient animals from the analysis has not been established yet, which hinders the model's ability to more accurately mimic the scenario in humans. To induce depression-like symptoms, rats received maternal deprivation (MD) during PND1-14, and/or chronic unpredictable stress (CUS) exposure. The latent profile analysis (LPA) was used to determine latent subgroups in treatment naive adult rats. The percentile method was used to distinguish sensitive and non-sensitive behaviors in rats. The sucrose preference rate of treatment naive adult rats was fit using a Beta distribution, while immobility time was fit using a Gamma distribution. Indexes of behavioral tests revealed the 4-class model as the best fit for treatment naive adult rats. The incidence of stress-resilience in MD rats was significantly higher than that in CUS rats and MD + CUS rats. There was a significantly higher incidence of stress-resilience in CUS rats compared with MD + CUS rats. Recovery rate of anhedonia-like and sub anhedonia-like behaviors in CUS rats was significantly higher than that in MD and MD + CUS rats. There was a significantly higher recovery rate of anhedonia-like behaviors in MD rats compared to MD + CUS rats. The percentile method is suitable for setting up an operational cutoff to classify depression-like, sub depression-like, and resilient behaviors in rats exposed to MD and CUS.

EPIDEMIOLOGY OF INJURIES AND DISEASES DUE TO OVERUSE IN RUGBY: OBSERVATIONAL STUDY OF THE PLAYERS OF “CUS PERUGIA RUGBY”

Directory of Open Access Journals (Sweden)

Michele Bisaccia

2016-08-01

Full Text Available Background: Rugby is a contact sport and for this reason is very demanding from a physical point of view. Up to now few studies describe the incidence and types of the most frequent traumas. The present study aims to evaluate the epidemiology of the major accidents related to the practice of this sport. Materials and methods: We collected data on a total of 321 players belonging to the Sports Club "CUS Rugby Perugia" for a total of three years taking into consideration the type of injury, the part of the body concerned, if the injury occurred during official competitions or in training, and also the lapse of time necessary for recovery. Results: We had a total of 240 accidents (45.8% of minor gravity, 36.6% of average gravity and 17.6% serious. In relation to the type of trauma, we noticed that minor injuries consisted in most cases and above all in facial injuries, while the average and the serious severity accidents affected in most cases the knees: (sprains, meniscal and ligamentous tears. Discussion: By analyzing the collected data we have noticedthat the highest number of accidents occurred during official competitions, and especially during the last minutes of the game, probably due to a greater muscle fatigue. The role of the players is also important because it correlates to a different type of risk. Conclusions: This study confirms that rugby has a higher accident rate than other contact sports. Therefore specific training strategies and techniques should be implemented, in order to reduce the incidence of injuries, especially at the level of the lower limbs.

Genomic organization of the canine herpesvirus US region.

Science.gov (United States)

Haanes, E J; Tomlinson, C C

1998-02-01

Canine herpesvirus (CHV) is an alpha-herpesvirus of limited pathogenicity in healthy adult dogs and infectivity of the virus appears to be largely limited to cells of canine origin. CHV's low virulence and species specificity make it an attractive candidate for a recombinant vaccine vector to protect dogs against a variety of pathogens. As part of the analysis of the CHV genome, the authors determined the complete nucleotide sequence of the CHV US region as well as portions of the flanking inverted repeats. Seven full open reading frames (ORFs) encoding proteins larger than 100 amino acids were identified within, or partially within the CHV US: cUS2, cUS3, cUS4, cUS6, cUS7, cUS8 and cUS9; which are homologs of the herpes simplex virus type-1 US2; protein kinase; gG, gD, gI, gE; and US9 genes, respectively. An eighth ORF was identified in the inverted repeat region, cIR6, a homolog of the equine herpesvirus type-1 IR6 gene. The authors identified and mapped most of the major transcripts for the predicted CHV US ORFs by Northern analysis.

DESAJUSTE EDUCATIVO POR REGIONES EN COLOMBIA: ¿COMPETENCIA POR SALARIOS O POR PUESTOS DE TRABAJO?

Directory of Open Access Journals (Sweden)

Maribel Castillo Caicedo

2007-06-01

Full Text Available Este trabajo aporta una perspectiva del fenómeno de la sobreeducación, entendida como un desajuste por exceso, entre el nivel educativo alcanzado por el individuo y el exigido por el puesto de trabajo en el cual se desempeña; esto se debe a que existe una demanda laboral estrecha de puestos de trabajo para personas calificadas en Colombia. Se analizan las contribuciones empíricas existentes y el debate sobre las mismas; se examinan las teorías que permiten explicar la existencia de un desajuste educativo y se realiza una revisión de la literatura internacional y nacional sobre el tema. Adicionalmente, se plantean una serie de hipótesis para desarrollar un esquema que permita determinar el comportamiento del individuo en el fenómeno de la sobreeducación.

Effects of cell condition, pH, and temperature on lead, zinc, and copper sorption to Acidithiobacillus caldus strain BC13

International Nuclear Information System (INIS)

Aston, John E.; Apel, William A.; Lee, Brady D.; Peyton, Brent M.

2010-01-01

Research highlights: →At. caldus sorbs lead, zinc, and copper across a range of pH and temperature. →At. caldus shows a relatively high sorption capacity for zinc and copper at low pH. → Lead, zinc, and copper sorption decreases in tertiary mixtures. → Copper appears to sorb via a different mechanism(s) than lead or zinc. - Abstract: This study describes the effects of cell condition, pH, and temperature on lead, zinc, and copper sorption to Acidithiobacillus caldus strain BC13 with a Langmuir model. Copper exhibited the highest loading capacity, 4.76 ± 0.28 mmol g -1 , to viable cells at pH 5.5. The highest k L (binding-site affinity) observed was 61.2 ± 3.0 L mmol -1 to dehydrated cells at pH 4.0. The pHs that maximized loading capacities and binding-site affinities were generally between 4.0 and 5.5, where the sum of free-proton and complexed-metal concentrations was near a minimum. Of additional importance, lead, zinc, and copper sorbed to viable cells at pH values as low as 1.5. Previous studies with other acidithiobacilli did not measure viable-cell sorption below pH 4.0. In separate experiments, desorption studies showed that far less copper was recovered from viable cells than any other metal or cell condition, suggesting that uptake may play an important role in copper sorption by At. caldus strain BC13. To reflect an applied system, the sorption of metal mixtures was also studied. In these experiments, lead, zinc, and copper sorption from a tertiary mixture were 40.2 ± 4.3%, 28.7 ± 3.8%, and 91.3 ± 3.0%, respectively, of that sorbed in single-metal systems.

Too much of a good thing: blocking noradrenergic facilitation in medial prefrontal cortex prevents the detrimental effects of chronic stress on cognition.

Science.gov (United States)

Jett, Julianne D; Morilak, David A

2013-03-01

Cognitive impairments associated with dysfunction of the medial prefrontal cortex (mPFC) are prominent in stress-related psychiatric disorders. We have shown that enhancing noradrenergic tone acutely in the rat mPFC facilitated extra-dimensional (ED) set-shifting on the attentional set-shifting test (AST), whereas chronic unpredictable stress (CUS) impaired ED. In this study, we tested the hypothesis that the acute facilitatory effect of norepinephrine (NE) in mPFC becomes detrimental when activated repeatedly during CUS. Using microdialysis, we showed that the release of NE evoked in mPFC by acute stress was unchanged at the end of CUS treatment. Thus, to then determine if repeated elicitation of this NE activity in mPFC during CUS may have contributed to the ED deficit, we infused a cocktail of α(1)-, β(1)-, and β(2)-adrenergic receptor antagonists into the mPFC prior to each CUS session, then tested animals drug free on the AST. Antagonist treatment prevented the CUS-induced ED deficit, suggesting that NE signaling during CUS compromised mPFC function. We confirmed that this was not attributable to sensitization of adrenergic receptor function following chronic antagonist treatment, by administering an additional microinjection into the mPFC immediately prior to ED testing. Acute antagonist treatment did not reverse the beneficial effects of chronic drug treatment during CUS, nor have any effect on baseline ED performance in chronic vehicle controls. Thus, we conclude that blockade of noradrenergic receptors in mPFC protected against the detrimental cognitive effects of CUS, and that repeated elicitation of noradrenergic facilitatory activity is one mechanism by which chronic stress may promote mPFC cognitive dysfunction.

Desajuste educativo por regiones en Colombia: ¿competencia por salarios o por puestos de trabajo?

Directory of Open Access Journals (Sweden)

Castillo Caicedo Maribel

2007-08-01

Full Text Available Este trabajo aporta una perspectiva del fenómeno de la sobreeducación,
entendida como un desajuste por exceso, entre el nivel educativo alcanzado
por el individuo y el exigido por el puesto de trabajo en el cual se
desempeña; esto se debe a que existe una demanda laboral estrecha de
puestos de trabajo para personas calificadas en Colombia. Se analizan las
contribuciones empíricas existentes y el debate sobre las mismas; se
examinan las teorías que permiten explicar la existencia de un desajuste
educativo y se realiza una revisión de la literatura internacional y
nacional sobre el tema. Adicionalmente, se plantean una serie de hipótesis
para desarrollar un esquema que permita determinar el comportamiento
del individuo en el fenómeno de la sobreeducación.

Structural Insights into the PorK and PorN Components of the Porphyromonas gingivalis Type IX Secretion System.

Directory of Open Access Journals (Sweden)

Dhana G Gorasia

2016-08-01

Full Text Available The type IX secretion system (T9SS has been recently discovered and is specific to Bacteroidetes species. Porphyromonas gingivalis, a keystone pathogen for periodontitis, utilizes the T9SS to transport many proteins including the gingipain virulence factors across the outer membrane and attach them to the cell surface via a sortase-like mechanism. At least 11 proteins have been identified as components of the T9SS including PorK, PorL, PorM, PorN and PorP, however the precise roles of most of these proteins have not been elucidated and the structural organization of these components is unknown. In this study, we purified PorK and PorN complexes from P. gingivalis and using electron microscopy we have shown that PorN and the PorK lipoprotein interact to form a 50 nm diameter ring-shaped structure containing approximately 32-36 subunits of each protein. The formation of these rings was dependent on both PorK and PorN, but was independent of PorL, PorM and PorP. PorL and PorM were found to form a separate stable complex. PorK and PorN were protected from proteinase K cleavage when present in undisrupted cells, but were rapidly degraded when the cells were lysed, which together with bioinformatic analyses suggests that these proteins are exposed in the periplasm and anchored to the outer membrane via the PorK lipid. Chemical cross-linking and mass spectrometry analyses confirmed the interaction between PorK and PorN and further revealed that they interact with the PG0189 outer membrane protein. Furthermore, we established that PorN was required for the stable expression of PorK, PorL and PorM. Collectively, these results suggest that the ring-shaped PorK/N complex may form part of the secretion channel of the T9SS. This is the first report showing the structural organization of any T9SS component.

Structural Insights into the PorK and PorN Components of the Porphyromonas gingivalis Type IX Secretion System.

Science.gov (United States)

Gorasia, Dhana G; Veith, Paul D; Hanssen, Eric G; Glew, Michelle D; Sato, Keiko; Yukitake, Hideharu; Nakayama, Koji; Reynolds, Eric C

2016-08-01

The type IX secretion system (T9SS) has been recently discovered and is specific to Bacteroidetes species. Porphyromonas gingivalis, a keystone pathogen for periodontitis, utilizes the T9SS to transport many proteins including the gingipain virulence factors across the outer membrane and attach them to the cell surface via a sortase-like mechanism. At least 11 proteins have been identified as components of the T9SS including PorK, PorL, PorM, PorN and PorP, however the precise roles of most of these proteins have not been elucidated and the structural organization of these components is unknown. In this study, we purified PorK and PorN complexes from P. gingivalis and using electron microscopy we have shown that PorN and the PorK lipoprotein interact to form a 50 nm diameter ring-shaped structure containing approximately 32-36 subunits of each protein. The formation of these rings was dependent on both PorK and PorN, but was independent of PorL, PorM and PorP. PorL and PorM were found to form a separate stable complex. PorK and PorN were protected from proteinase K cleavage when present in undisrupted cells, but were rapidly degraded when the cells were lysed, which together with bioinformatic analyses suggests that these proteins are exposed in the periplasm and anchored to the outer membrane via the PorK lipid. Chemical cross-linking and mass spectrometry analyses confirmed the interaction between PorK and PorN and further revealed that they interact with the PG0189 outer membrane protein. Furthermore, we established that PorN was required for the stable expression of PorK, PorL and PorM. Collectively, these results suggest that the ring-shaped PorK/N complex may form part of the secretion channel of the T9SS. This is the first report showing the structural organization of any T9SS component.

The PorX response regulator of the Porphyromonas gingivalis PorXY two-component system does not directly regulate the Type IX secretion genes but binds the PorL subunit.

Directory of Open Access Journals (Sweden)

Maxence S Vincent

2016-08-01

Full Text Available The Type IX secretion system (T9SS is a versatile multi-protein complex restricted to bacteria of the Bacteriodetes phylum and responsible for the secretion of surface attachment of diverse proteins that participate to S-layer formation, gliding motility or pathogenesis. The T9SS is poorly characterized but a number of proteins involved in the assembly of the secretion apparatus in the oral pathogen Porphyromonas gingivalis have been identified based on genome substractive analyses. Among these proteins, PorY and PorX encode typical two-component system (TCS sensor and CheY-like response regulator respectively. Although the porX and porY genes do not localize at the same genetic locus, it has been proposed that PorXY form a bona fide TCS. Deletion of the porX in P. gingivalis causes a slight decrease of the expression of a number of other T9SS genes, including sov, porT, porP, porK, porL, porM, porN and porY. Here, we show that PorX and the soluble cytoplasmic domain of PorY interact. Using electrophoretic mobility shift, DNA-protein co-purification and heterologous host expression assays, we showed that PorX does not bind and does not directly regulate expression of the T9SS genes. Finally, we show that PorX interacts with the cytoplasmic domain of PorL, a component of the T9SS membrane core complex and propose that the CheY-like PorX protein might be involved in the dynamics of the T9SS.

The PorX Response Regulator of the Porphyromonas gingivalis PorXY Two-Component System Does Not Directly Regulate the Type IX Secretion Genes but Binds the PorL Subunit

Science.gov (United States)

Vincent, Maxence S.; Durand, Eric; Cascales, Eric

2016-01-01

The Type IX secretion system (T9SS) is a versatile multi-protein complex restricted to bacteria of the Bacteriodetes phylum and responsible for the secretion or cell surface exposition of diverse proteins that participate to S-layer formation, gliding motility or pathogenesis. The T9SS is poorly characterized but a number of proteins involved in the assembly of the secretion apparatus in the oral pathogen Porphyromonas gingivalis have been identified based on genome substractive analyses. Among these proteins, PorY, and PorX encode typical two-component system (TCS) sensor and CheY-like response regulator respectively. Although the porX and porY genes do not localize at the same genetic locus, it has been proposed that PorXY form a bona fide TCS. Deletion of porX in P. gingivalis causes a slight decrease of the expression of a number of other T9SS genes, including sov, porT, porP, porK, porL, porM, porN, and porY. Here, we show that PorX and the soluble cytoplasmic domain of PorY interact. Using electrophoretic mobility shift, DNA-protein co-purification and heterologous host expression assays, we demonstrate that PorX does not bind T9SS gene promoters and does not directly regulate expression of the T9SS genes. Finally, we show that PorX interacts with the cytoplasmic domain of PorL, a component of the T9SS membrane core complex and propose that the CheY-like PorX protein might be involved in the dynamics of the T9SS. PMID:27630829

Identification and Analysis of a Novel Gene Cluster Involves in Fe2+ Oxidation in Acidithiobacillus ferrooxidans ATCC 23270, a Typical Biomining Acidophile.

Science.gov (United States)

Ai, Chenbing; Liang, Yuting; Miao, Bo; Chen, Miao; Zeng, Weimin; Qiu, Guanzhou

2018-07-01

Iron-oxidizing Acidithiobacillus spp. are applied worldwide in biomining industry to extract metals from sulfide minerals. They derive energy for survival through Fe 2+ oxidation and generate Fe 3+ for the dissolution of sulfide minerals. However, molecular mechanisms of their iron oxidation still remain elusive. A novel two-cytochrome-encoding gene cluster (named tce gene cluster) encoding a high-molecular-weight cytochrome c (AFE_1428) and a c 4 -type cytochrome c 552 (AFE_1429) in A. ferrooxidans ATCC 23270 was first identified in this study. Bioinformatic analysis together with transcriptional study showed that AFE_1428 and AFE_1429 were the corresponding paralog of Cyc2 (AFE_3153) and Cyc1 (AFE_3152) which were encoded by the extensively studied rus operon and had been proven involving in ferrous iron oxidation. Both AFE_1428 and AFE_1429 contained signal peptide and the classic heme-binding motif(s) as their corresponding paralog. The modeled structure of AFE_1429 showed high resemblance to Cyc1. AFE_1428 and AFE_1429 were preferentially transcribed as their corresponding paralogs in the presence of ferrous iron as sole energy source as compared with sulfur. The tce gene cluster is highly conserved in the genomes of four phylogenetic-related A. ferrooxidans strains that were originally isolated from different sites separated with huge geographical distance, which further implies the importance of this gene cluster. Collectively, AFE_1428 and AFE_1429 involve in Fe 2+ oxidation like their corresponding paralog by integrating with the metalloproteins encoded by rus operon. This study provides novel insights into the Fe 2+ oxidation mechanism in Fe 2+ -oxidizing A. ferrooxidans ssp.

Prior exposure to repeated immobilization or chronic unpredictable stress protects from some negative sequels of an acute immobilization.

Science.gov (United States)

Pastor-Ciurana, Jordi; Rabasa, Cristina; Ortega-Sánchez, Juan A; Sanchís-Ollè, Maria; Gabriel-Salazar, Marina; Ginesta, Marta; Belda, Xavier; Daviu, Núria; Nadal, Roser; Armario, Antonio

2014-05-15

Exposure to chronic unpredictable stress (CUS) is gaining acceptance as a putative animal model of depression. However, there is evidence that chronic exposure to stress can offer non-specific stress protection from some effects of acute superimposed stressors. We then compared in adult male rats the protection afforded by prior exposure to CUS with the one offered by repeated immobilization on boards (IMO) regarding some of the negative consequences of an acute exposure to IMO. Repeated exposure to IMO protected from the negative consequences of an acute IMO on activity in an open-field, saccharin intake and body weight gain. Active coping during IMO (struggling) was markedly reduced by repeated exposure to the same stressor, but it was not affected by a prior history of CUS, suggesting that our CUS protocol does not appear to impair active coping responses. CUS exposure itself caused a strong reduction of activity in the open-field but appeared to protect from the hypo-activity induced by acute IMO. Moreover, prior CUS offered partial protection from acute IMO-induced reduction of saccharin intake and body weight gain. It can be concluded that a prior history of CUS protects from some of the negative consequences of exposure to a novel severe stressor, suggesting the development of partial cross-adaptation whose precise mechanisms remain to be studied. Copyright © 2014 Elsevier B.V. All rights reserved.

Urtica dioica leaves modulates hippocampal smoothened-glioma associated oncogene-1 pathway and cognitive dysfunction in chronically stressed mice.

Science.gov (United States)

Patel, Sita Sharan; Mahindroo, Neeraj; Udayabanu, Malairaman

2016-10-01

The present study was aimed to evaluate the effect of Urtica dioica (UD) extract against chronic unpredictable stress (CUS)-induced associative memory dysfunction and attempted to explore the possible mechanism. Male Swiss albino mice (25-30g) were divided into six groups, viz. group-I received 0.3% carboxymethyl cellulose and served as control (CTRL), group II was exposed to CUS (21days) and received vehicle (CUS), group III was subjected to CUS and received Hypericum perforatum extract (350mg/kg, p.o.) (CUS+HYP), group IV received Hypericum perforatum extract (350mg/kg, p.o.) (CTRL+HYP); group V was subjected to CUS and received UD extract (50mg/kg, p.o.) (CUS+UD), group VI received UD extract (50mg/kg, p.o.) (CTRL+UD). CUS significantly induced body weight loss (p<0.05) and associative memory impairment in step down task (p<0.05) as compared to control mice. CUS significantly downregulated Smo (p<0.05), Gli1 (p<0.01), cyclin D1 (p<0.05), BDNF (p<0.01), TrKB (p<0.01) and MAPK1 (p<0.01) mRNA expression in hippocampus as compared to control mice. CUS significantly increased the levels of TBARS (p<0.01) and nitric oxide (p<0.001), and decreased catalase (p<0.001) and total thiol (p<0.01) in plasma resulting in oxidative stress and inflammation. Chronic UD administration significantly reverted CUS mediated body weight loss (p<0.05) and cognitive impairment (p<0.05). UD administration significantly decreased the levels of TBARS (p<0.01) and nitric oxide (p<0.05), and increased the levels of catalase (p<0.01) and total thiol (p<0.05) in plasma. Chronic UD administration significantly upregulated hippocampal Smo (p<0.05), Gli1 (p<0.001), cyclin D1 (p<0.05), BDNF (p<0.05), TrKB (p<0.05) and MAPK1 (p<0.05) in stressed mice. Further, UD extract did not reverse cyclopamine induced downregulation of Gli1 and Ptch1 mRNA in hippocampal slices. UD modulated Smo-Gli1 pathway in the hippocampus as well as exerted anti-inflammatory and antioxidant effects. UD extract might prove

Electrochemiluminescence quenching of luminol by CuS in situ grown on reduced graphene oxide for detection of N-terminal pro-brain natriuretic peptide.

Science.gov (United States)

Li, Xiaojian; Lu, Peng; Wu, Bin; Wang, Yaoguang; Wang, Huan; Du, Bin; Pang, Xuehui; Wei, Qin

2018-07-30

A novel electrochemiluminescence (ECL) signal-off strategy based on CuS in situ grown on reduced graphene oxide (CuS-rGO) quenching luminol/H 2 O 2 system was firstly proposed. Luminol was grafted on the surface of Au@Fe 3 O 4 -Cu 3 (PO 4 ) 2 nanoflowers (Luminol-Au@Fe 3 O 4 -Cu 3 (PO 4 ) 2 ) which exhibited excellent catalytic effect towards the reduction of H 2 O 2 to enhance the ECL intensity of luminol. Cu 3 (PO 4 ) 2 nanoflowers showed large surface area which can immobilize more Fe 3 O 4 and Au nanoparticles. The quenching mechanism of CuS-rGO was due to ECL resonance energy transfer (RET). The spectral overlap between fluorescence spectrum of Luminol-Au@Fe 3 O 4 -Cu 3 (PO 4 ) 2 and UV-vis absorption spectrum of CuS-rGO revealed that resonance energy transfer was possible. Au nanoparticles were immobilized on the surface of CuS-rGO to capture secondary antibodies. After a sandwich-type immunoreaction, a remarkable decrease of ECL signal was observed. Under the optimal conditions, the immunosensor showed excellent performance for N-terminal pro-brain natriuretic peptide (NT-proBNP) detection with a wide detection range from 0.5 pg mL -1 to 20 ng mL -1 and a low detection limit of 0.12 pg mL -1 (S/N = 3). The prepared NT-proBNP immunosensor displayed high sensitivity, excellent stability and good specificity. Copyright © 2018 Elsevier B.V. All rights reserved.

Encefalopatía por priones

Directory of Open Access Journals (Sweden)

Carlos Colegial

1999-01-01

Full Text Available Las encefalopatías espongiformes por priones son enfermedades neurodegenerativas que pueden ser esporádicas o transmisibles, ya sea por mecanismos infecciosos o hereditarios. Su investigación ha planteado enormes retos y en el recorrido histórico en busca de su causa dos médicos han recibido el premio Nobel de Medicina: Carleton Gajdusek, por sus trabajos en Nueva Guinea donde describió la transmisión infecciosa por ritos canibalísticos, que llevó a estudios de transmisión experimental en chimpancés y a su teoría de los "virus lentos" (por el largo período de incubación de la enfermedad.

Protracted effects of chronic stress on serotonin dependent thermoregulation

Science.gov (United States)

Natarajan, Reka; Northrop, Nicole A.; Yamamoto, Bryan K.

2016-01-01

Chronic stress is known to affect serotonin (5HT) neurotransmission in the brain and to alter body temperature. Body temperature is controlled in part, by the medial preoptic area of the hypothalamus (mPOA). To investigate the effect of chronic stress on 5HT and how it affects body temperature regulation, we examined whether exposure to a chronic unpredictable stress paradigm (CUS) produces long-term alterations in thermoregulatory function of the mPOA through decreased 5HT neurotransmission. Adult male Sprague-Dawley rats underwent 21 days of CUS. Four days after last stress exposure, basal body temperature in the home cage and body temperature in a cold room maintained at 10°C were recorded. CUS rats had significantly higher subcutaneous basal body temperature at 13:00 h compared to unstressed (NoStress) rats. Whereas the NoStress rats were able to significantly elevate body temperature from basal levels at 30 and 60 min of exposure to the cold room, the CUS rats showed a hypothermic response to the cold. Treatment during CUS with metyrapone, a corticosterone synthesis inhibitor, blocked stress-induced decrease in body temperature in response to the cold challenge. CUS also decreased 5HT transporter protein immunoreactivity in the mPOA and 5HT2A/C agonist injection into the mPOA after CUS exposure caused stressed rats to exhibit a sensitized hyperthermic response to cold. These results indicate that CUS induced changes to the 5HTergic system alters mPOA function in thermoregulation. These findings help explain mechanisms underlying chronic stress induced disorders such as chronic fatigue syndrome wherein long lasting thermoregulatory deficits are observed. PMID:26414686

Pyrosequencing reveals correlations between extremely acidophilic bacterial communities with hydrogen sulphide concentrations, pH and inert polymer coatings at concrete sewer crown surfaces.

Science.gov (United States)

Pagaling, E; Yang, K; Yan, T

2014-07-01

To investigate the acidophilic bacterial communities involved in microbially induced concrete corrosion (MICC). Our study sites located downstream from a forced main provided a unique opportunity to study the microbial communities involved in MICC under different environmental conditions (gradients of atmospheric H(2)S, sulphate concentration and pH) and under pipe modifications (coated vs uncoated). Bacterial cell density estimated by both cultivation- and DNA-based methods was low in the corroded sewer samples. Pyrosequencing and cloning showed that Mycobacterium and Acidithiobacillus dominated the acidophilic microbial communities. Methylacidiphilum was also dominant in samples where methane was detected. Correlation analysis indicated that Mycobacterium and Acidithiobacillus were significantly affected by pH and that Mycobacterium could better withstand highly acidic conditions compared to Acidithiobacillus. Communities dominated by Mycobacterium favoured conditions in the lined sewer pipes, while communities with a higher relative abundance of Acidithiobacillus favoured the unlined sewer pipes. Identifying the key micro-organisms involved in MICC and knowing how they interact with their environment are essential aspects for identifying steps towards concrete corrosion management. © 2014 The Society for Applied Microbiology.

Sonochemical synthesis of cooper II sulfide nanoparticles and their use as radiolytic stabilizer in polyvinyl chloride matrix

International Nuclear Information System (INIS)

Freitas, Danubia Maria da Silva; Lima, Thaysa Araujo de; Aquino, Katia Aparecida da Silva; Araujo, Elmo S.

2013-01-01

Cooper (II) sulfide (CuS) was synthesized by sonochemical method. CuS crystals with hexagonal structure exhibit irregular aggregates of particles with an average size in the range of 250-900 nm. Commercial Polyvinyl chloride (PVC) containing CuS nanoparticles (PVC/CuS) at concentrations of 0.10; 0.30; 0.50 and 0.70 wt% were investigated. The samples were irradiated with gamma radiation ( 60 Co) at room temperature and air atmosphere. The viscosity-average molar mass (M v ) was measured for PVC systems without nanoparticles and with nanoparticles. Decrease in viscosity molar mass was observed when the systems were gamma irradiated reflect the random scission effects that take place in the main chain. Degradation index (DI) value was also obtained by viscosity analysis. DI results showed that the addition of CuS nanoparticles at 0.5 wt% into PVC matrix decreased the number of main chain scissions at dose of 25 kGy and was calculated a protection of 84% in PVC matrix. CuS nanoparticles act as free radical scavenger into gamma-irradiated PVC systems. The interactions between CuS and PVC favor action of nanoparticles as a good plasticizer in the PVC molecule. (author)

CIDADES CONTEMPORÂNEAS: "LÓCUS" DO CAPITALISMO PÓS-MODERNO

Directory of Open Access Journals (Sweden)

Ubiratan Francisco de Oliveira

2011-08-01

Full Text Available As cidades da/na sociedade contemporânea expressam, das mais variadas formas e dimensões, a organização social de seus sujeitos. Mais que isso, elas expressam a estrutura do sistema produtivo ao qual elas estão inseridas como sedes burocráticas desse sistema, o lugar do comando e da organização da produção capitalista. Se há uma rede mundial que organiza o sistema capitalista, essa rede só é possível por conta das cidades. Elas são os nós da rede produtiva contemporânea, donas de uma estrutura de transmissão de informações e produção de conhecimentos jamais tidos na história da humanidade. Contudo, a velocidade com a qual evolui esse sistema, as cidades proporcionam uma imensidão de problemas relacionados com espaço, tempo e sujeitos. Contraditórios e multifacetados, eles proporcionam várias formas de territorialização nas cidades dos guetos, dos recantos, do trabalho, da arte, da cultura e, sobretudo, da hegemônica força da economia sobre essas dimensões sociais.

Casipoemas por Navidad : (1969-2010)

OpenAIRE

Sena Medina, Guillermo

2011-01-01

PRESENTACIÓN AL AIRE DE LA POESÍA RELIGIOSA Y NAVIDEÑA DE GUILLERMO SENA MEDINA Constituye un gran honor hacer la presentación de Guillermo Sena Medina por un doble motivo; por la larga y sincera amistad que nos une desde hace muchos años al socaire de nuestra común afición por la Historia, como cronistas oficiales de nuestros municipios; y, sobre todo y particularmente, por su rica y profunda personalidad como hombre de letras, nacida de su aún más rica y profunda personalidad humana. A...

Chemical and surface analysis during evolution of arsenopyrite oxidation by Acidithiobacillus thiooxidans in the presence and absence of supplementary arsenic

Energy Technology Data Exchange (ETDEWEB)

Ramírez-Aldaba, Hugo [Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo (Mexico); Valles, O. Paola [Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo (Mexico); Instituto Tecnológico de Durando, UPIDET, Av. Felipe Pescador 1830 Ote. Col. Nueva Vizcaya, 34080 Durango, Dgo (Mexico); Vazquez-Arenas, Jorge [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Iztapalapa, México DF 09340 (Mexico); Rojas-Contreras, J. Antonio [Instituto Tecnológico de Durando, UPIDET, Av. Felipe Pescador 1830 Ote. Col. Nueva Vizcaya, 34080 Durango, Dgo (Mexico); Valdez-Pérez, Donato [Instituto Politécnico Nacional, UPALM, Edif. Z-4 3er Piso, CP 07738 México D.F (Mexico); Ruiz-Baca, Estela [Facultad de Ciencias Químicas, Departamento de Ciencia de Materiales, Universidad Juárez del Estado de Durango (UJED), Av. Veterinaria S/N, Circuito Universitario, Col. Valle del Sur, 34120 Durango, Dgo (Mexico); and others

2016-10-01

Bioleaching of arsenopyrite presents a great interest due to recovery of valuable metals and environmental issues. The current study aims to evaluate the arsenopyrite oxidation by Acidithiobacillus thiooxidans during 240 h at different time intervals, in the presence and absence of supplementary arsenic. Chemical and electrochemical characterizations are carried out using Raman, AFM, SEM-EDS, Cyclic Voltammetry, EIS, electrophoretic and adhesion forces to comprehensively assess the surface behavior and biooxidation mechanism of this mineral. These analyses evidence the formation of pyrite-like secondary phase on abiotic control surfaces, which contrast with the formation of pyrite (FeS{sub 2})-like, orpiment (As{sub 2}S{sub 3})-like and elementary sulfur and polysulfide (S{sub n}{sup 2−}/S{sup 0}) phases found on biooxidized surfaces. Voltammetric results indicate a significant alteration of arsenopyrite due to (bio)oxidation. Resistive processes determined with EIS are associated with chemical and electrochemical reactions mediated by (bio)oxidation, resulting in the transformation of arsenopyrite surface and biofilm direct attachment. Charge transfer resistance is increased when (bio)oxidation is performed in the presence of supplementary arsenic, in comparison with lowered abiotic control resistances obtained in its absence; reinforcing the idea that more stable surface products are generated when As(V) is in the system. Biofilm structure is mainly comprised of micro-colonies, progressively enclosed in secondary compounds. A more compact biofilm structure with enhanced formation of secondary compounds is identified in the presence of supplementary arsenic, whereby variable arsenopyrite reactivity is linked and attributed to these secondary compounds, including S{sub n}{sup 2−}/S{sup 0}, pyrite-like and orpiment-like phases. - Highlights: • Biofilm structures occur as compact micro-colonies. • Surface transformation reactions control arsenopyrite and cell

Chemical and surface analysis during evolution of arsenopyrite oxidation by Acidithiobacillus thiooxidans in the presence and absence of supplementary arsenic

International Nuclear Information System (INIS)

Ramírez-Aldaba, Hugo; Valles, O. Paola; Vazquez-Arenas, Jorge; Rojas-Contreras, J. Antonio; Valdez-Pérez, Donato; Ruiz-Baca, Estela

2016-01-01

Bioleaching of arsenopyrite presents a great interest due to recovery of valuable metals and environmental issues. The current study aims to evaluate the arsenopyrite oxidation by Acidithiobacillus thiooxidans during 240 h at different time intervals, in the presence and absence of supplementary arsenic. Chemical and electrochemical characterizations are carried out using Raman, AFM, SEM-EDS, Cyclic Voltammetry, EIS, electrophoretic and adhesion forces to comprehensively assess the surface behavior and biooxidation mechanism of this mineral. These analyses evidence the formation of pyrite-like secondary phase on abiotic control surfaces, which contrast with the formation of pyrite (FeS_2)-like, orpiment (As_2S_3)-like and elementary sulfur and polysulfide (S_n"2"−/S"0) phases found on biooxidized surfaces. Voltammetric results indicate a significant alteration of arsenopyrite due to (bio)oxidation. Resistive processes determined with EIS are associated with chemical and electrochemical reactions mediated by (bio)oxidation, resulting in the transformation of arsenopyrite surface and biofilm direct attachment. Charge transfer resistance is increased when (bio)oxidation is performed in the presence of supplementary arsenic, in comparison with lowered abiotic control resistances obtained in its absence; reinforcing the idea that more stable surface products are generated when As(V) is in the system. Biofilm structure is mainly comprised of micro-colonies, progressively enclosed in secondary compounds. A more compact biofilm structure with enhanced formation of secondary compounds is identified in the presence of supplementary arsenic, whereby variable arsenopyrite reactivity is linked and attributed to these secondary compounds, including S_n"2"−/S"0, pyrite-like and orpiment-like phases. - Highlights: • Biofilm structures occur as compact micro-colonies. • Surface transformation reactions control arsenopyrite and cell interactions. • Toxic arsenic does not

Protracted effects of chronic stress on serotonin-dependent thermoregulation.

Science.gov (United States)

Natarajan, Reka; Northrop, Nicole A; Yamamoto, Bryan K

2015-01-01

Chronic stress is known to affect serotonin (5HT) neurotransmission in the brain and to alter body temperature. The body temperature is controlled in part, by the medial preoptic area (mPOA) of the hypothalamus. To investigate the effect of chronic stress on 5HT and how it affects body temperature regulation, we examined whether exposure to a chronic unpredictable stress (CUS) paradigm produces long-term alterations in thermoregulatory function of the mPOA through decreased 5HT neurotransmission. Adult male Sprague-Dawley rats underwent 21 d of CUS. Four days after the last stress exposure, basal body temperature in the home cage and body temperature in a cold room maintained at 10 °C were recorded. The CUS rats had significantly higher subcutaneous basal body temperature at 13:00 h compared to unstressed (NoStress) rats. Whereas the NoStress rats were able to significantly elevate body temperature from basal levels at 30 and 60 min of exposure to the cold room, the CUS rats showed a hypothermic response to the cold. Treatment during CUS with metyrapone, a corticosterone synthesis inhibitor, blocked stress-induced decrease in body temperature in response to the cold challenge. CUS also decreased 5HT transporter protein immunoreactivity in the mPOA and 5HT2A/C agonist injection into the mPOA after CUS exposure caused stressed rats to exhibit a sensitized hyperthermic response to cold. These results indicate that the CUS induced changes to the 5HTergic system alter mPOA function in thermoregulation. These findings help us to explain the mechanisms underlying chronic stress-induced disorders such as chronic fatigue syndrome wherein long lasting thermoregulatory deficits are observed.

Evolution of NADPH-cytochrome P450 oxidoreductases (POR) in Apiales - POR 1 is missing

DEFF Research Database (Denmark)

Andersen, Trine Bundgaard; Hansen, Niels Bjørn; Laursen, Tomas

2016-01-01

The NADPH-dependent cytochrome P450 oxidoreductase (POR) is the obligate electron donor to eukaryotic microsomal cytochromes P450 enzymes. The number of PORs within plant species is limited to one to four isoforms, with the most common being two PORs per plant. These enzymes provide electrons to ...... (available from the SRA at NCBI). All three genes were shown to be functional upon reconstitution into nanodiscs, confirming that none of the isoforms are pseudogenes....

Pre-gestational stress reduces the ratio of 5-HIAA to 5-HT and the expression of 5-HT1A receptor and serotonin transporter in the brain of foetal rat

Directory of Open Access Journals (Sweden)

Huang Yuejun

2012-02-01

Full Text Available Abstract Background Many studies have found that stress before or during pregnancy is linked to an increased incidence of behavioural disorders in offspring. However, few studies have investigated hypothalamic-pituitary-adrenal (HPA axis activity and the serotonergic system as a consequence of pregestational stress. In the present study, we investigated the effect of pre-gestational stress on HPA axis activity in maternal rats and their foetuses and examined whether changes in HPA axis activity of maternal rats produced functional changes in the serotonergic system in the brain of foetuses. Results We used the behavioural tests to assess the model of chronic unpredictable stress (CUS in maternal rats. We found the activity in the open field and sucrose consumption was lower for rats with CUS than for the controls. Body weight but not brain weight was higher for control foetuses than those from the CUS group. Serum corticosterone and corticotrophin-releasing hormone levels were significantly higher for mothers with CUS before pregnancy and their foetuses than for the controls. Levels of 5-hydroxytryptamine (5-HT were higher in the hippocampus and hypothalamus of foetuses in the CUS group than in the controls, and 5-hydroxyindoleacetic acid (5-HIAA levels were lower in the hippocampus in foetuses in the CUS group than in the control group. Levels of 5-HIAA in the hypothalamus did not differ between foetuses in the CUS group and in the control group. The ratio of 5-HIAA to 5-HT was significantly lower for foetuses in the CUS group than in the control group. Levels of 5-HT1A receptor were significantly lower in the foetal hippocampus in the CUS group than in the control group, with no significant difference in the hypothalamus. The levels of serotonin transporter (SERT were lower in both the foetal hippocampus and foetal hypothalamus in the CUS group than in the control group. Conclusions Our data demonstrate that pre-gestational stress alters HPA

Insights into the Quorum Sensing Regulon of the Acidophilic Acidithiobacillus ferrooxidans Revealed by Transcriptomic in the Presence of an Acyl Homoserine Lactone Superagonist Analogue

Directory of Open Access Journals (Sweden)

Sigde Mamani

2016-09-01

Full Text Available While a functional quorum sensing system has been identified in the acidophilic chemolithoautotroph Acidithiobacillus ferrooxidans ATCC 23270T and shown to modulate cell adhesion to solid substrates, nothing is known about the genes it regulates. To address the question of how quorum sensing controls biofilm formation in At. ferrooxidansT, the transcriptome of this organism in conditions in which quorum sensing response is stimulated by a synthetic superagonist AHL analogue has been studied. First, the effect on biofilm formation of a synthetic AHL tetrazolic analogue, tetrazole 9c, known for its agonistic QS activity, was assessed by fluorescence and electron microscopy experiments. A faster adherence of At. ferrooxidansT cells on sulfur coupons was observed. Then, tetrazole 9c was used in DNA microarray experiments that allowed the identification of genes regulated by quorum sensing signalling, and more particularly, those involved in early biofilm formation. Interestingly, afeI gene, encoding the AHL synthase, but not the At. ferrooxidans quorum sensing transcriptional regulator AfeR encoding gene, was shown to be regulated by quorum sensing. Data indicated that QS network represents at least 4.5 % (141 genes of the ATCC 23270T genome of which 42.5 % (60 genes are related to biofilm formation. Finally, AfeR was shown to bind specifically to the regulatory region of the afeI gene at the level of the palindromic sequence predicted to be the AfeR binding site. Our results give new insights on the response of At. ferrooxidans to quorum sensing and on biofilm biogenesis, opening new biological/chemical alternatives for bioleaching development and managing acid Mine/Rock drainage environmental damages.

Osteomalacia inducida por tumor: hemangiopericitoma rinosinusal

Directory of Open Access Journals (Sweden)

Enriqueta M. Serafini

2013-02-01

Full Text Available La osteomalacia inducida por tumor es una rara enfermedad del metabolismo óseo caracterizada por el aumento en la excreción de fosfato a nivel renal seguido de hipofosfatemia. Es causada por agentes fosfatúricos producidos por determinados tumores. La resección total del tumor resulta en la completa reversión de las anormalidades bioquímicas, la desaparición de las manifestaciones clínicas y los hallazgos en los estudios por imágenes. Presentamos el caso de un varón de 61 años con cuadro clínico y laboratorio compatibles con osteomalacia oncogénica inducida por tumor mesenquimático de localización rinosinusal. En nuestro caso el diagnóstico histológico correspondió a una neoplasia de tipo vascular: hemangiopericitoma.

MARKETING PROMOCIONAL COMO FERRAMENTA GERENCIAL PARA AUMENTAR A PRODUTIVIDADE E A QUALIDADE EM SERVIÇOS EDUCACIONAIS

OpenAIRE

Silva, Fabiana Ferreira; Silva, Aline Kelly Moura

2010-01-01

Este ensaio teórico-empírico apresenta como o conhecimento e a utilização das ferramentas do composto de marketing podem auxiliar no alcance dos objetivos organizacionais através do gerenciamento adequado do fluxo de informações na empresa. O lócus de investigação foi constituído por uma instituição de educação profissional reconhecida nacionalmente, que apesar de ter todos os seus processos padronizados e orientações específicas para cada ação, as unidades localizadas nas cidades do interior...

[Biomineralization of copper in Candida fukuyamaensis RCL-3].

Science.gov (United States)

Irazusta, Verónica; Michel, Lucas; de Figueroa, Lucía I C

2016-01-01

Candida fukuyamaensis RCL-3 yeast has the ability to decrease copper concentration in a culture medium. High copper concentrations change the cell color from white/cream to brown. The effect of color change ceases with the addition of KCN or when cells are grown in a culture medium without sulfate ions. These results could be associated with CuS bioaccumulation in the cell surface. This report revealed that mineralization would be a mechanism used by this yeast for copper bioremediation. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

Solvothermal synthesis of copper sulfide semiconductor micro/nanostructures

International Nuclear Information System (INIS)

Liu, Jun; Xue, Dongfeng

2010-01-01

Covellite copper sulfide (CuS) micro/nanometer crystals in the shape of hierarchical doughnut-shaped, superstructured spheric-shaped and flowerlike architectures congregated from those nanoplates with the thickness of 20-100 nm have been prepared by a solvothermal method. The as-obtained CuS products were characterized by means of scanning electron microscopy (SEM), X-ray diffractometry (XRD) and energy-dispersive X-ray spectroscopy (EDS). A systematic investigation has been carried out to understand the factors influencing the evolution of CuS particle morphology which found to be predominant by solvent, surfactant, sulfur resource and copper salt. The possible formation mechanism for the nanostructure formation was also discussed. These CuS products show potential applications in solar cell, photothermal conversion and chemical sensor.

Internal medicine point-of-care ultrasound assessment of left ventricular function correlates with formal echocardiography.

Science.gov (United States)

Johnson, Benjamin K; Tierney, David M; Rosborough, Terry K; Harris, Kevin M; Newell, Marc C

2016-02-01

Although focused cardiac ultrasonographic (FoCUS) examination has been evaluated in emergency departments and intensive care units with good correlation to formal echocardiography, accuracy for the assessment of left ventricular systolic function (LVSF) when performed by internal medicine physicians still needs independent evaluation. This prospective observational study in a 640-bed, academic, quaternary care center, included 178 inpatients examined by 10 internal medicine physicians who had completed our internal medicine bedside ultrasound training program. The ability to estimate LVSF with FoCUS as "normal," "mild to moderately decreased," or "severely decreased" was compared with left ventricular ejection fraction (>50%, 31-49%, and internal medicine physician-performed FoCUS and formal echocardiography for any LVSF impairment was "good/substantial" with κ = 0.77 (p Internal medicine physicians using FoCUS identify normal versus decreased LVSF with high sensitivity, specificity, and "good/substantial" interrater agreement when compared with formal echocardiography. These results support the role of cardiac FoCUS by properly trained internal medicine physicians for discriminating normal from reduced LVSF. © 2015 Wiley Periodicals, Inc.

A Pilot Comparative Study of Quantitative Ultrasound, Conventional Ultrasound, and MRI for Predicting Histology-Determined Steatosis Grade in Adult Nonalcoholic Fatty Liver Disease.

Science.gov (United States)

Paige, Jeremy S; Bernstein, Gregory S; Heba, Elhamy; Costa, Eduardo A C; Fereirra, Marilia; Wolfson, Tanya; Gamst, Anthony C; Valasek, Mark A; Lin, Grace Y; Han, Aiguo; Erdman, John W; O'Brien, William D; Andre, Michael P; Loomba, Rohit; Sirlin, Claude B

2017-05-01

The purpose of this study is to explore the diagnostic performance of two investigational quantitative ultrasound (QUS) parameters, attenuation coefficient and backscatter coefficient, in comparison with conventional ultrasound (CUS) and MRI-estimated proton density fat fraction (PDFF) for predicting histology-confirmed steatosis grade in adults with nonalcoholic fatty liver disease (NAFLD). In this prospectively designed pilot study, 61 adults with histology-confirmed NAFLD were enrolled from September 2012 to February 2014. Subjects underwent QUS, CUS, and MRI examinations within 100 days of clinical-care liver biopsy. QUS parameters (attenuation coefficient and backscatter coefficient) were estimated using a reference phantom technique by two analysts independently. Three-point ordinal CUS scores intended to predict steatosis grade (1, 2, or 3) were generated independently by two radiologists on the basis of QUS features. PDFF was estimated using an advanced chemical shift-based MRI technique. Using histologic examination as the reference standard, ROC analysis was performed. Optimal attenuation coefficient, backscatter coefficient, and PDFF cutoff thresholds were identified, and the accuracy of attenuation coefficient, backscatter coefficient, PDFF, and CUS to predict steatosis grade was determined. Interobserver agreement for attenuation coefficient, backscatter coefficient, and CUS was analyzed. CUS had 51.7% grading accuracy. The raw and cross-validated steatosis grading accuracies were 61.7% and 55.0%, respectively, for attenuation coefficient, 68.3% and 68.3% for backscatter coefficient, and 76.7% and 71.3% for MRI-estimated PDFF. Interobserver agreements were 53.3% for CUS (κ = 0.61), 90.0% for attenuation coefficient (κ = 0.87), and 71.7% for backscatter coefficient (κ = 0.82) (p hepatic steatosis grade in patients with NAFLD.

An efficient chronic unpredictable stress protocol to induce stress-related responses in C57BL/6 mice.

Science.gov (United States)

Monteiro, Susana; Roque, Susana; de Sá-Calçada, Daniela; Sousa, Nuno; Correia-Neves, Margarida; Cerqueira, João José

2015-01-01

Exposure to chronic stress can have broad effects on health ranging from increased predisposition for neuropsychiatric disorders to deregulation of immune responses. The chronic unpredictable stress (CUS) protocol has been widely used to study the impact of stress exposure in several animal models and consists in the random, intermittent, and unpredictable exposure to a variety of stressors during several weeks. CUS has consistently been shown to induce behavioral and immunological alterations typical of the chronic stress-response. Unfortunately C57BL/6 mice, one of the most widely used mouse strains, due to the great variety of genetically modified lines, seem to be resistant to the commonly used 4-week-long CUS protocol. The definition of an alternative CUS protocol allowing the use of C57BL/6 mice in chronic stress experiments is a need. Here, we show that by extending the CUS protocol to 8 weeks is possible to induce a chronic stress-response in C57BL/6 mice, as revealed by abrogated body weight gain, increased adrenals weight, and an overactive hypothalamic-pituitary-adrenal axis with increased levels of serum corticosterone. Moreover, we also observed stress-associated behavioral alterations, including the potentiation of anxious-like and depressive-like behaviors and a reduction of exploratory behavior, as well as subtle stress-related changes in the cell population of the thymus and of the spleen. The present protocol for C57BL/6 mice consistently triggers the spectrum of CUS-induced changes observed in rats and, thus, will be highly useful to researchers that need to use this particular mouse strain as an animal model of neuropsychiatric disorders and/or immune deregulation related to CUS.

Porøse materialer

DEFF Research Database (Denmark)

Hansen, Ernst Jan de Place

2000-01-01

Dette undervisningsnotat er en samling af noter, der refererer til den indledende del af kurset Materialmekanik og Porøse materailer på Insitut for Bærende Konstruktiner og Materialer (BKM).......Dette undervisningsnotat er en samling af noter, der refererer til den indledende del af kurset Materialmekanik og Porøse materailer på Insitut for Bærende Konstruktiner og Materialer (BKM)....

Association Between Weekend Catch-up Sleep and Lower Body Mass: Population-Based Study.

Science.gov (United States)

Im, Hee-Jin; Baek, Shin-Hye; Chu, Min Kyung; Yang, Kwang Ik; Kim, Won-Joo; Park, Seong-Ho; Thomas, Robert J; Yun, Chang-Ho

2017-07-01

To determine if weekend catch-up sleep (CUS) impacts body mass index (BMI) in the general population. A stratified random sample (2156 subjects; age 19-82 years old, 43.0 ± 14.5; 1183 male) from the general population was evaluated, in 2010, using face-to-face interviews about sociodemographic characteristics, height, weight, habitual sleep duration, and time-in-bed at night on weekdays and weekend, sleep-related profiles, mood and anxiety scales, and comorbid-medical conditions. Weekend CUS was identified when nocturnal sleep extension occurred over the weekend, and this was quantified. Average sleep duration, BMI, and chronotype were determined. The association of BMI with the presence and the amount of weekend CUS was analyzed, independent of average sleep duration, chronotype, and sociodemographic factors. BMI and average sleep duration was 23.0 ± 3.0 kg/m2 and 7.3 ± 1.2 hours, respectively. The weekend CUS group consisted of 932 subjects (43.1%) who slept longer on weekend than weekdays by 1.8 ± 1.1 hours. Weekend CUS subjects had a significantly lower BMI (22.8 ± 0.19 kg/m2) than the non-CUS (23.1 ± 0.19 kg/m2) group, after adjustment for age, sex, average sleep duration, chronotype, other sociodemographic factors, and anxiety/mood status (p = .01) The relationship between weekend CUS and BMI was dose-dependent (p = 0.02): Every additional hour of weekend CUS was associated with a decrease of 0.12 kg/m2 in BMI (95% confidence interval, -0.23 to -0.02). Weekend sleep extension may have biological protective effects in preventing sleep-restriction induced or related obesity. The results suggest a simple population-level strategy to minimize effects of sleep loss. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Effect of high dietary zinc on plasma ceruloplasmin and erythrocyte superoxide dismutase activities in copper-depleted and repleted rats.

Science.gov (United States)

Panemangalore, M; Bebe, F N

1996-01-01

The effect of moderately high dietary zinc (Zn) on the activities of plasma (PL) ceruloplasmin (CP), and PL and erythrocyte (RBC) copper (Cu), Zn superoxide dismutase (SOD) was determined in weanling rats fed Cu-deficient (DEF; CON; 5 mg Cu/kg) copper diets containing normal or high Zn (HZn; 60 mg/kg) for 4 wk and supplemented with oral Cu (CuS; 5 mg/L) in drinking water for 0, 1, 3, or 7 d. PL Cu decreased (67% compared to CON; p DEF and increased to control level after 3 d of CuS; increased in the MAR group after 1 d of CuS. HZn reduced overall PL Cu by 27% in all groups, but did not alter the linear increase in PL Cu between 0 and 3 d of Cu S. PL CP activity altered concomitantly with PL Cu levels: The time course of increase in CP activity after 0-3 d of CuS was not influenced by HZn in the diet and CP declined in the DEF group by 92%. There was no correlation between dietary Cu level and PL CP. PL SOD activity decreased by 46% (p DEF group, increased to control activity after 1 d of CuS and declined slightly after 7 d; MAR diet did not alter PL SOD. HZn diet increased PL SOD activity in all groups by 150%, reduced activity in the DEF and MAR groups by 65 and 37% and delayed the recovery of PL SOD after CuS. RBC SOD declined in the DEF and MAR groups by 56 and 33% (p < or = 0.05) and did not respond to CuS; HZn diet did not influence RBC SOD activity. These data indicate that moderately high Zn in the diet reduces PL Cu, but not PL CP activity or the recovery of PL Cu or CP activity after oral CuS of Cu-deficient rats, modifies the response of PL SOD to dietary Cu, but does not influence RBC SOD activity.

Hydrothermal synthesis of copper sulfide with novel hierarchical structures and its application in lithium-ion batteries

International Nuclear Information System (INIS)

Chen, Guang-Yi; Wei, Zhi-Yong; Jin, Bo; Zhong, Xiao-Bin; Wang, Heng; Zhang, Wan-Xi; Liang, Ji-Cai; Jiang, Qing

2013-01-01

Novel stick-like CuS hierarchical structures have been fabricated by a hydrothermal approach use β-cyclodextrin as ligand and structure-directing agent. SEM and TEM characterizations show that the CuS stick-like structures are composed of tens to hundreds of well-arranged and self-assembled nanoplates with a thickness of about 25 nm. The mechanism for the formation of the final stick-like hierarchical structures is proposed and discussed. β-cyclodextrin is found to be the key factor in controlling the morphologies. Meanwhile, the possibility of using CuS as the electrode material for lithium ion batteries (LIBs) is studied. Electrochemical measurements reveal that the as-prepared CuS exhibits outstanding cycle stability, indicating that it might find possible application as a cathode material for LIBs in the long term.

Cross-Comparison of Leaching Strains Isolated from Two Different Regions: Chambishi and Dexing Copper Mines

OpenAIRE

Ngom, Baba; Liang, Yili; Liu, Xueduan

2014-01-01

A cross-comparison of six strains isolated from two different regions, Chambishi copper mine (Zambia, Africa) and Dexing copper mine (China, Asia), was conducted to study the leaching efficiency of low grade copper ores. The strains belong to the three major species often encountered in bioleaching of copper sulfide ores under mesophilic conditions: Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferriphilum. Prior to their study in bioleaching, the different...

Influencia de la concentración de hierro y pH iniciales en un proceso de biodesulfurización de carbón – ensayos a nivel de laboratorio

Directory of Open Access Journals (Sweden)

Gerardo Andrés Caicedo Pineda

2011-07-01

Full Text Available Título en ingles: Particle size, iron concentration and pH influence in biodesulfurization process of coal – laboratory tests   Resumen   A un carbón proveniente del municipio de Puerto Libertador, Córdoba-Colombia (2.34% de azufre total, con 1.34% pirítico, 0.90% orgánico y 0.10% de sulfatos, se le aplicó un cultivo mixto de Acidithiobacillus ferrooxidans y Acidithiobacillus thiooxidans, con el fin de evaluar procesos de biodesulfurización en suspensión, a partir de variables que influyen en el proceso: concentración inicial de hierro y pH de la solución lixiviante, bajo dos configuraciones de tamaño de partícula: pasante malla 8 (-malla 8 y pasante malla 60 (-malla 60, acorde con la serie Tyler de tamices. Los procesos de biodesulfurización se evaluaron cada dos días, mediante mediciones de la concentración de hierro, pH, potencial de óxido-reducción y crecimiento celular, en la solución. A partir de los ensayos realizados, se alcanzaron oxidaciones de azufre pirítico por encima del 50%, después de 12 días de proceso. Se pudo constatar que tanto el tipo de carbón tratado, como de las condiciones evaluadas, inciden en el grado de lixiviación alcanzado. La mejor eficiencia del proceso se observó al utilizar concentraciones de hierro iniciales menores a 1200 ppm y un pH inicial entre 1.5 y 1.3.   Palabras clave: Acidithiobacillus, biodesulfurización, carbón, hierro removido, pirita.   Abstract   Biodesulfurization process for Colombian coal (2.34% total sulfur: 1.34% as pyritic, 0.90% as organic and 0.10% from sulfates from municipality of Puerto Libertador (Córdoba, Colombia was carried out. A mixed culture of A. ferrooxidans and A. thiooxidans was used. The study was mainly focused on the influence of pH, and iron concentration in coal leaching process. Two mineral particle sizes were evaluated: less 8 mesh (-malla 8 and less 60 mesh (-malla 60, Tyler series. Biodesulfurization processes were determined by

Verdad por definición

OpenAIRE

Garrido Garrido, Julián

1997-01-01

Not available.La verdad por definición es un tipo peculiar de verdad científica, distinguible de las verdades lógicas, matemáticas y empíricas. La definición, por su parte, designa diversos procedimientos de asignación de significado, cuyas diferencias exigen una adjetivación cuidadosa: definiciones ostensivas y operacionales, definiciones de diccionario y definiciones teóricas. Pero sólo las del último tipo son verdaderas por definición. En el presente artículo se precisa el concepto formal ...

Electrocardiografo por computadora

OpenAIRE

Tinoco Hernandez, Rosanna; Paredes Bejarano, Margarita; Romero Chaglia, Norman; Yapur Auad, Miguel Eduardo

2009-01-01

El presente trabajo trata sobrees el diseño y la implementación de un graficador de señales cardiacas por computadora, para lo cual diseñamos un circuito electrónico capaz de recibir la senal analógica proveniente de la actividad electrica del corazón , amplificarla, y luego convertirla en una señal digital para ser procesada por software y finalmente ser graficada, siendo posible así observar la señal cardiaca en el monitor de un computador como un tren de pulsos. Cabe destacar que par...

Point-of-care ultrasonography adoption in Canada: using diffusion theory and the Evaluation Tool for Ultrasound skills Development and Education (ETUDE).

Science.gov (United States)

Woo, Michael Y; Frank, Jason R; Lee, A Curtis

2014-09-01

Point-of-care ultrasonography (PoCUS) first appeared in the 1980s in North America, but the extent of the diffusion of its adoption is unknown. We characterized early PoCUS adoption by emergency physicians in Canada and its barriers to use using Rogers' diffusion of innovations theory. We developed a questionnaire based on a pilot study and literature review to assess past, current, and potential use of PoCUS and potential barriers to adoption. A Dillman technique for electronic surveys was used for dissemination. Using Rogers' diffusion of innovations theory, we developed and validated the Evaluation Tool for Ultrasound skills Development and Education (ETUDE). ETUDE scores allowed categorization of respondents into innovators, early adopters, majority, and nonadopters. Descriptive statistics, correlations, and χ² statistics were used to analyze the data. The 296 respondents (36.4% of 814 surveyed) had a median age of 40 and were 72.5% male. Adoption scores using ETUDE revealed nonadopters (18.8%), majority (28.7%), early adopters (34.5%), and innovators (18.0%). Respondents endorsed "always" using PoCUS currently and in the future for focused assessment with sonography in trauma (FAST) (current 41.8%/future 88.4%), first trimester pregnancy (current 23.3%/future 73.7%), suspected abdominal aortic aneurysm (current 32.7%/future 92.6%), basic cardiac indications (current 30.7%/future 87.5%), and central venous catheterization (current 17.0%/future 80.3%). Several barriers to PoCUS were identified for part-time emergency physicians and those working in inner-city/urban/suburban settings. This is the first study to determine the state of adoption and barriers to the introduction of PoCUS in Canadian emergency medicine practice. The novel validated ETUDE instrument should be used to evaluate the uptake of PoCUS over time.

Acute agmatine administration, similar to ketamine, reverses depressive-like behavior induced by chronic unpredictable stress in mice.

Science.gov (United States)

Neis, Vivian B; Bettio, Luis E B; Moretti, Morgana; Rosa, Priscila B; Ribeiro, Camille M; Freitas, Andiara E; Gonçalves, Filipe M; Leal, Rodrigo B; Rodrigues, Ana Lúcia S

Agmatine is an endogenous neuromodulator that has been shown to have antidepressant-like properties. We have previously demonstrated that it can induce a rapid increase in BDNF levels after acute administration, suggesting that agmatine may be a fast-acting antidepressant. To investigate this hypothesis, the present study evaluated the effects of a single administration of agmatine in mice subjected to chronic unpredictable stress (CUS), a model of depression responsive only to chronic treatment with conventional antidepressants. The ability of agmatine to reverse CUS-induced behavioral and biochemical alterations was evaluated and compared with those elicited by the fast-acting antidepressant (ketamine) and the conventional antidepressant (fluoxetine). After exposed to CUS for 14days, mice received a single oral dose of agmatine (0.1mg/kg), ketamine (1mg/kg) or fluoxetine (10mg/kg), and were submitted to behavioral evaluation after 24h. The exposure to CUS caused an increased immobility time in the tail suspension test (TST) but did not change anhedonic-related parameters in the splash test. Our findings provided evidence that, similarly to ketamine, agmatine is able to reverse CUS-induced depressive-like behavior in the TST. Western blot analyses of prefrontal cortex (PFC) demonstrated that mice exposed to CUS and/or treated with agmatine, fluoxetine or ketamine did not present alterations in the immunocontent of synaptic proteins [i.e. GluA1, postsynaptic density protein 95 (PSD-95) and synapsin]. Altogether, our findings indicate that a single administration of agmatine is able to reverse behavioral alterations induced by CUS in the TST, suggesting that this compound may have fast-acting antidepressant-like properties. However, there was no alteration in the levels of synaptic proteins in the PFC, a result that need to be further investigated in other time points. Copyright © 2016 Elsevier Inc. All rights reserved.

Structural linear measurements in the newborn brain: accuracy of cranial ultrasound compared to MRI

International Nuclear Information System (INIS)

Leijser, Lara M.; Srinivasan, Latha; Cowan, Frances M.; Rutherford, Mary A.; Counsell, Serena J.; Allsop, Joanna M.

2007-01-01

Structural size in the neonatal brain is of clinical importance. Cranial ultrasonography (cUS) is the primary method used for evaluating the neonatal brain and it is important to know whether linear measurements made using this technique are accurate. To compare linear measurements of different cerebral structures made from neonatal cUS and contemporaneous MRI. Preterm and term infants studies with cUS and MRI on the same day were studied. Linear measurements made using both techniques from many cerebral structures were compared using a paired t-test. A total of 44 sets of scans from 26 preterm and 8 term infants were assessed. Small but significant differences between the cUS and MRI measurements (P<0.05) were found for the ventricular index, the posterior horn depth of the lateral ventricle, the extracerebral space and interhemispheric fissure, and the cortex of the cingulate gyrus. No significant differences were found for any other measurements. Linear measurements from cUS are accurate for most neonatal cerebral structures. Significant differences compared to MRI were found for a few structures, but only for the cortex were the absolute differences marked and possibly of clinical importance. (orig.)

Synthesis of one-dimensional copper sulfide nanorods as high-performance anode in lithium ion batteries.

Science.gov (United States)

Li, Xue; He, Xinyi; Shi, Chunmei; Liu, Bo; Zhang, Yiyong; Wu, Shunqing; Zhu, Zizong; Zhao, Jinbao

2014-12-01

Nanorod-like CuS and Cu2 S have been fabricated by a hydrothermal approach without using any surfactant and template. The electrochemical behavior of CuS and Cu2 S nanorod anodes for lithium-ion batteries reveal that they exhibit stable lithium-ion insertion/extraction reversibility and outstanding rate capability. Both of the electrodes exhibit excellent capacity retentions irrespective of the rate used, even at a high current density of 3200 mA g(-1) . More than 370 mAh g(-1) can be retained for the CuS electrode and 260 mAh g(-1) for the Cu2 S electrode at the high current rate. After 100 cycles at 100 mA g(-1) , the obtained CuS and Cu2 S electrodes show discharge capacities of 472 and 313 mAh g(-1) with retentions of 92% and 96%, respectively. Together with the simplicity of fabrication and good electrochemical properties, CuS and Cu2 S nanorods are promising anode materials for practical use the next-generation lithium-ion batteries. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Celulitis por citomegalovirus Cytomegalovirus cellulitis

Directory of Open Access Journals (Sweden)

A. Ruiz Lascano

2002-12-01

Full Text Available Las lesiones cutáneas por citomegalovirus (CMV son infrecuentes y a menudo una manifestación tardía de una enfermedad sistémica, que generalmente anuncia un curso fatal. Comunicamos un caso de celulitis por CMV: una mujer de 70 años con trasplante renal efectuado 1 mes antes de la consulta, terapia inmunosupresora con ciclosporina A y metilprednisona. La paciente ingresó por fiebre, dolor e impotencia funcional en pierna derecha. Comprobamos la existencia de una placa de 8 por 4 cm eritematoedematosa. La tratamos con antibióticos sin mejoría, por lo que realizamos un estudio histopatológico de piel que mostró cambios citopáticos compatibles con infección por CMV. Los cultivos bacteriológicos y micológicos fueron negativos. La inmunohistoquímica específica para CMV y el estudio de reacción en cadena de la polimerasa (PCR de la biopsia de piel fueron positivas, al igual que la antigenemia. El tratamiento con ganciclovir produjo la mejoría del cuadro clínico. En la literatura revisada no hemos encontrado la celulitis como manifestación de enfermedad cutánea por CMV.Cutaneous lesions in CMV infection are rare, often a late manifestation of systemic infection, and usually herald a fatal course. A 70 year-old woman received a kidney transplantation one month before consulting and immunosuppressive therapy that included cyclosporine A and methylprednisone. She complained of fever, local pain in her right leg, and an erythematous and swelling plaque. She was treated with intravenous antibiotics without improvement. A skin biopsy was performed and the tissue obtained was sent for bacterial and fungal cultures as well as for histological examination. Cultures were negative. The biopsy showed CMV cytopathic changes. Immunoperoxidase staining was positive for CMV and polymerase chain reaction (PCR testing revealed CMV DNA. She was treated with ganciclovir with resolution of the lesion. CMV cellulitis is a rare cutaneous manifestation

Tendencia de la mortalidad por cáncer en Chile según diferencias por nivel educacional, 2000-2010

Directory of Open Access Journals (Sweden)

Cristian A. Herrera Riquelme

2015-01-01

Full Text Available Objetivo. Caracterizar la tendencia de la mortalidad por cáncer en Chile según diferencias por nivel educacional en el período 2000-2010 en la población mayor de 20 años. Métodos. Cálculo de las tasas de mortalidad específica por cáncer ajustadas por edad para diferentes niveles educacionales (NE, para el período 2000-2010. Las tasas obtenidas se analizaron con un modelo de regresión de Poisson, calculando el índice de desigualdad relativa (IDR y el índice de desigualdad de la pendiente (IDP para cada año. Resultados. Se registraron 232 541 muertes por cáncer en el período 2000-2010. Los tipos de cáncer más frecuentes fueron de mama, estómago y vesícula biliar en mujeres; y estómago, próstata y pulmón en hombres. Las tasas de mortalidad por cáncer estandarizadas por edad fueron mayores en los NE más bajos, excepto para el de mama en mujer y el de pulmón en hombres. Las mayores diferencias se encontraron en el de vesícula biliar en mujeres y el de estómago en hombres, con mayores tasas de mortalidad específica de hasta 49 y 63 veces respectivamente, para NE bajo respecto al NE alto. Entre 2000 y 2010, las diferencias en mortalidad por NE se redujeron para todos los cánceres combinados en ambos géneros, mama en mujeres, y pulmón y estómago en hombres. Conclusiones. Durante el período estudiado, la mortalidad por cáncer en Chile estuvo fuertemente asociada al NE de la población. Esta información debe ser considerada al definir estrategias nacionales para reducir la mortalidad específica por cáncer en los grupos más desprotegidos.

Multilinguismo em Bonfim/RR : o ensino de língua portuguesa no contexto da diversidade linguística

OpenAIRE

Santos, Alessandra de Souza

2013-01-01

Esta tese tem por objetivo analisar o ensino da Língua Portuguesa no contexto de multilinguismo. O lócus da pesquisa são as escolas urbanas da rede pública de ensino do município de Bonfim, situado na região leste do estado de Roraima, a 125 km da capital Boa Vista. A diversidade linguística e cultural são marcas facilmente perceptíveis a todos que chegam em Bonfim, lá encontram-se diferentes grupos indígenas (Macuxi, Ingarikó e Wai-wai línguas Karib e Wapichana língua Aruak), guianenses, ...

Processos de transferência de N em curto e longo prazo em plantios mistos de Eucalyptus grandis e Acacia mangium

OpenAIRE

Ranieri Ribeiro Paula

2015-01-01

A intensificação ecológica das plantações florestais tropicais (PFT) pela introdução de árvores fixadoras de nitrogênio (AFN) pode levar a maior produção de biomassa e ao aumento dos serviços ecossistêmicos (e.g. manutenção dos recursos hídricos e da biodiversidade, recuperação de áreas degradas e sequestro de carbono). Essa intensificação é particularmente importante nos trópicos, por causa da escassez de solos ricos em nutrientes destinados ao estabelecimento das PFT, e devido aos altos cus...

Muerte materna por malaria grave por Plasmodium vivax

Directory of Open Access Journals (Sweden)

Nancy Arróspide

Full Text Available Se presenta el caso de una mujer de 19 años con 29 semanas de gestación, procedente de Llumpe (Ancash con antecedentes de viajes a las localidades de Chanchamayo (Junín y Rinconada (Ancash. Ingresó al Hospital de Chacas (Ancash por presentar mal estado general, deshidratación, dificultad respiratoria, ictericia, sensación de alza térmica y dolor abdominal, tuvo reporte de: hemoparásitos 60% en frotis sanguíneo. Fue transferida al Hospital Ramos Guardia (Huaraz donde presentó mayor dificultad respiratoria, coluria, hematuria, disminución del débito urinario y reporte de Plasmodium (+, luego fue transferida al Hospital Cayetano Heredia (Lima donde ingresó a la Unidad de Cuidados Intensivos (UCI, con evolución a falla multiorgánica, óbito fetal y muerte materna. Se confirmó infección por Plasmodium vivax. Destacamos la importancia de mejorar nuestras capacidades de diagnóstico y manejo para brindar un tratamiento adecuado y oportuno.

Desenvolvimento de um kit de irrigação por microtubos com moto-bomba propulsionada por energia solar

OpenAIRE

Luiz Ricardo Sobenko

2016-01-01

O bombeamento de água por meio da energia solar vem se mostrando uma alternativa para localidades onde outras fontes de energia não estão disponíveis ou são limitadas. Torna-se interessante aliar essa alternativa a um sistema de irrigação que opera com vazão e pressão relativamente baixas, como a irrigação localizada por microtubos, possibilitando assim a obtenção de alta eficiência. No presente trabalho teve-se por objetivo dimensionar e avaliar um kit de irrigação por microtubos, alimentado...

Tendencia de la mortalidad por cáncer en Chile según diferencias por nivel educacional, 2000-2010

OpenAIRE

Cristian A. Herrera Riquelme; Lucy Kuhn-Barrientos; Roberto Rosso Astorga; Jorge Jiménez de la Jara

2015-01-01

Objetivo. Caracterizar la tendencia de la mortalidad por cáncer en Chile según diferencias por nivel educacional en el período 2000-2010 en la población mayor de 20 años. Métodos. Cálculo de las tasas de mortalidad específica por cáncer ajustadas por edad para diferentes niveles educacionales (NE), para el período 2000-2010. Las tasas obtenidas se analizaron con un modelo de regresión de Poisson, calculando el índice de desigualdad relativa (IDR) y el índice de desigualdad de la pendiente (ID...

Polución por material particulado fino (PM 2,5) incrementa las hospitalizaciones por insuficiencia cardiaca

OpenAIRE

Castro, Pablo; Vera, Jeanette; Cifuentes, Luis; Wellenius, Gregory; Verdejo, Hugo; Sepúlveda, Luis; Vukasovic, José Luis; Llevaneras, Silvana

2010-01-01

Antecedentes: Estudios recientes han reportado una asociación entre la contaminación ambiental por material particulado (PM) y el riesgo de hospitalizaciones de pacientes con insuficiencia cardiaca (IC). La región metropolitana de nuestro país constituye un área geográfica en la cual la contaminación es especialmente relevante, asociándose a incrementos periódicos en la morbimortalidad por causa respiratoria. Sin embargo el efecto de la polución por PM en la morbilidad de pacientes con IC no ...

Regulation of brain-derived neurotrophic factor (BDNF) in the chronic unpredictable stress rat model and the effects of chronic antidepressant treatment

DEFF Research Database (Denmark)

Larsen, Marianne H; Mikkelsen, Jens D; Hay-Schmidt, Anders

2010-01-01

Chronic unpredictable stress (CUS) is a widely used animal model of depression. The present study was undertaken to investigate behavioral, physiological and molecular effects of CUS and/or chronic antidepressant treatment (venlafaxine or imipramine) in the same set of animals. Anhedonia, a core ...

Serial cranial ultrasonography or early MRI for detecting preterm brain injury?

NARCIS (Netherlands)

Plaisier, Annemarie; Raets, Marlou M A; Ecury-Goossen, Ginette M; Govaert, Paul; Feijen-Roon, Monique; Reiss, Irwin K M; Smit, Liesbeth S; Lequin, Maarten H; Dudink, Jeroen

OBJECTIVE: To investigate detection ability and feasibility of serial cranial ultrasonography (CUS) and early MRI in preterm brain injury. DESIGN: Prospective cohort study. SETTING: Level III neonatal intensive care unit. PATIENTS: 307 infants, born below 29 weeks of gestation. METHODS: Serial CUS

Síndrome de Munchausen por mandato

OpenAIRE

Esteban, Miguel A.; Pérez, Miriam R.; Bracco, Anahí

2006-01-01

El Síndrome de Munchausen por mandato, "un trastorno ficticio, por el cual la enfermedad del niño es inducida, promovida o provocada por la persona más próxima a él, generalmente su madre", es todavía mal conocido y su génesis imperfectamente comprendida. Esta comunicación está destinada a esclarecer al pediatra esta patología, con elevada morbilidad y secuelas, como así también de altísima mo...

Magnetic resonance and cranial ultrasound characteristics of periventricular white matter abnormalities in newborn infants

International Nuclear Information System (INIS)

Childs, Anne-Marie; Cornette, Luc; Ramenghi, Luca A.; Tanner, Steven F.; Arthur, Rosemary J.; Martinez, Delia; Levene, Malcolm I.

2001-01-01

OBJECTIVE: To characterize the range of abnormalities within the periventricular white matter (PVWM) in a cohort of newborns using magnetic resonance (MR) brain imaging and to compare the focal MR abnormalities with the cranial ultrasound (CUS) findings. METHODS: Retrospective study of MR brain and CUS findings of infants born in the 18-month period 1998-1999. PVWM abnormalities were identified by MR and focal lesions were characterized by size, number and distribution using a grading scale. Correspondence with CUS findings was assessed. RESULTS: 175 MR examinations corresponding to n = 105 preterm infants, (median GA 28, range 23-36 weeks) and n = 25 term infants (median GA 39, range 37-42 weeks) were analysed for PVWM abnormalities. In the preterm group, MR demonstrated a normal PVWM in n = 76, focal areas of altered signal intensity (SI) in PVWM in n = 26 and venous infarction inn 3. In the term group, MR demonstrated a normal PVWM in n = 15, focal areas of altered SI in PVWM in n = 4, oedematous PVWM in n = 2 and a middle cerebral artery infarction in n = 4. All infants with normal MR had normal CUS findings. A focal PVWM SI abnormality detectable on MR corresponded with an abnormality on CUS in only n = 10/30. CONCLUSIONS: MR appears considerably more sensitive than CUS in demonstrating the existence and extent of focal PVWM lesions in newborn infants. Satisfactory correspondence between the two imaging investigations is obtained only for cystic PVWM lesions. Childs, A.-M. et al. (2001)

Persistent Increase in Microglial RAGE Contributes to Chronic Stress-Induced Priming of Depressive-like Behavior.

Science.gov (United States)

Franklin, Tina C; Wohleb, Eric S; Zhang, Yi; Fogaça, Manoela; Hare, Brendan; Duman, Ronald S

2018-01-01

Chronic stress-induced inflammatory responses occur in part via danger-associated molecular pattern (DAMP) molecules, such as high mobility group box 1 protein (HMGB1), but the receptor(s) underlying DAMP signaling have not been identified. Microglia morphology and DAMP signaling in enriched rat hippocampal microglia were examined during the development and expression of chronic unpredictable stress (CUS)-induced behavioral deficits, including long-term, persistent changes after CUS. The results show that CUS promotes significant morphological changes and causes robust upregulation of HMGB1 messenger RNA in enriched hippocampal microglia, an effect that persists for up to 6 weeks after CUS exposure. This coincides with robust and persistent upregulation of receptor for advanced glycation end products (RAGE) messenger RNA, but not toll-like receptor 4 in hippocampal microglia. CUS also increased surface expression of RAGE protein on hippocampal microglia as determined by flow cytometry and returned to basal levels 5 weeks after CUS. Importantly, exposure to short-term stress was sufficient to increase RAGE surface expression as well as anhedonic behavior, reflecting a primed state that results from a persistent increase in RAGE messenger RNA expression. Further evidence for DAMP signaling in behavioral responses is provided by evidence that HMGB1 infusion into the hippocampus was sufficient to cause anhedonic behavior and by evidence that RAGE knockout mice were resilient to stress-induced anhedonia. Together, the results provide evidence of persistent microglial HMGB1-RAGE expression that increases vulnerability to depressive-like behaviors long after chronic stress exposure. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

DESGASTE POR ABRASIÓN DEL ACERO API 5L X65 REVESTIDO CON NIOBIO POR ASPERSIÓN TÉRMICA A PLASMA Y CON INCONEL 625 POR SOLDADURA

Directory of Open Access Journals (Sweden)

JOSE MATOS

2012-01-01

Full Text Available El objetivo de este trabajo fue evaluar y caracterizar el comportamiento mecánico en desgaste del acero API 5L X65, revestido con niobio en comparación al desempeño del revestimiento de la aleación de inconel 625 empleados en la industria de petróleo y gas. El revestimiento de niobio fue obtenido por el proceso de aspersión térmica a plasma de arco no transferido y el revestimiento inconel 625 por soldadura con electrodo revestido. La resistencia al desgaste por abrasión fue evaluada según la norma Petrobras N-2568, en un tribómetro CTER, la rugosidad y el volumen de material desgastado se determinó a través de perfilometría y la dureza de los revestimientos por microscopia Vickers. Los revestimientos obtenidos fueron caracterizados respecto a su morfología por microscopia electrónica de barrido (MEB y microscopía óptica (MO. La mayor dureza del revestimiento con niobio obtenido puede haber contribuido a reducir la tasa de desgaste en comparación con el revestimiento de inconel 625.

CARACTERÍSTICAS DA VIOLÊNCIA SEXUAL SOFRIDA POR CRIANÇAS ASSISTIDAS POR UM PROGRAMA DE APOIO

OpenAIRE

KELLY LINHARES VASCONCELOS; ADRIANA GOMES NOGUEIRA FERREIRA; ELIANY NAZARÉ OLIVEIRA; DANIELLE D\\u2019ÁVILA SIQUEIRA; PATRÍCIA NEYVA DA COSTA PINHEIRO

2010-01-01

En Brasil, las estadísticas de la violencia sexual contra niños están lejos de reflejar la verdadera realidad actual debido a la baja notificación de los casos. La finalidad de este estudio fue caracterizar el abuso sexual sufrido por niños asistidos por el Programa Sentinela y el perfil del agresor, en Sobral-Ceará, en el periodo que va del 2002 al 2006. La muestra no probabilística intencional fue compuesta por 50 víctimas de abuso sexual y de las mismas, el 66% es del sexo femenino, con pr...

Abdome agudo por obstrução por ileobiliar

Directory of Open Access Journals (Sweden)

Márcia Cristina de Alencastro

Full Text Available OBJETIVO: descrever a experiência na abordagem dos doentes com abdome agudo por obstrução por IB, desde o diagnóstico até o tratamento definitivo. MÉTODOS: estudo retrospectivo incluindo todos os casos de IB tratados em um período de 23 anos. De acordo com a abordagem cirúrgica realizada, os pacientes foram divididos em dois grupos (1 enterolitotomia com colecistectomia no segundo momento; e (2 enterolitotomia, colecistectomia e abordagem da fístula. RESULTADOS: Doze pacientes foram incluídos, sendo 11 mulheres (91,6%, com média de idade de 72,2 anos. Todos os pacientes apresentavam doenças associadas, principalmente hipertensão arterial sistêmica (75%. Dois pacientes não apresentavam sintomas significativos de obstrução intestinal. O diagnóstico de IB foi realizado em seis pacientes (50% antes da laparotomia. O grupo 1 foi constituído de oito pacientes e o grupo 2 de quatro, e a morbidade foi, respectivamente, 33,3% e 8,3%. A mortalidade foi 16,6% (um paciente de cada grupo. CONCLUSÃO: O manejo do IB deve ser individualizado. O tratamento da obstrução mediante remoção do cálculo biliar por enterotomia proximal é a escolha inicial para o tratamento do IB. A colecistectomia e a correção da fístula bilioentérica podem ser realizadas juntamente com a remoção do cálculo, no entanto, em pacientes com comorbidades significativas, esses procedimentos devem ser realizados posteriormente.

Brazilian Credit Union Member Groups: Borrower-dominated, Saver-dominated or Neutral Behavior?

Directory of Open Access Journals (Sweden)

Valéria Gama Fully Bressan

2013-01-01

Full Text Available Theoretical models concerning Credit Unions (CUs suggest that the type of CU domination determines the way it allocates the monetary value it generates. A borrower- (saver- dominated CU benefits borrower (saver members at the expenses of saver (borrower members, and a neutral CU equally benefits its member groups.This paper applies direct measure of monetary benefits to each member group (Patin & McNiel, 1991a to testfor the existence of dominated behavior in Brazilian CUs, and is the first to apply panel data regressions to identify the determinants of CUs behavior. We use a unique panel data with 40,664 observations taken from 533 CUs affiliated with the largest Brazilian cooperative network. Results indicate Brazilian CUs are dominated by borrowers, but behave close to neutrality. Panel regression estimates show that common or multiple bond type,size and overdue loans of a CU have no effect on its behavior, the greater the total amount of loans over social capital and adjusted equity over total assets are the more likely a CU is borrower dominated, and the greater the age and current operational expenses over total asset of a CU are the more likely a CU is saver dominated.

Bioleaching of low grade uranium ore containing pyrite using A. ferrooxidans and A. thiooxidans

International Nuclear Information System (INIS)

Alexey Borisovich Umanskii; Anton Mihaylovich Klyushnikov

2013-01-01

A process of uranium extraction from ore containing 3.1 % pyrite by bacterial leaching was investigated in shaken flasks during 90 days. The highest uranium recovery amounting to 85.1 % was obtained using binary mixture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans that was exceeding results obtained by traditional acid leaching technique up to 27 %. High uranium recovery was founded to be due to the high degree of pyrite dissolution that can be readily achieved by bacterial leaching (up to 98.0 %). (author)

Uso das diretrizes para tratamento da úlcera por pressão por enfermeiros de um hospital geral

Directory of Open Access Journals (Sweden)

Elaine Maria Leite Rangel

2009-03-01

Full Text Available Este estudo objetivou identificar a freqüência do uso das diretrizes para o tratamento da úlcera por pressão(UP por enfermeiros de um hospital geral no interior do estado de São Paulo. É transversal de caráterdescritivo com análise quantitativa de dados. Amostra de 25 enfermeiros. Para a coleta de dados utilizou-se uminstrumento, construído a partir das diretrizes para o tratamento da UP. As questões foram relacionadas aostipos de intervenções usadas pelos enfermeiros para o tratamento da UP em estágio I, II, com necrose e comtecido de granulação. Para UP em estágio I, 24 (96% enfermeiros sempre realizavam a mudança de decúbito.Nas úlceras em estágio II a utilização de óleos vegetais na ferida era realizada sempre por 10 (40%enfermeiros e o curativo de hidrocolóide nunca era utilizado por 12 (57,1% enfermeiros. Em UP com necrose alimpeza com povidine era realizada por 4 (17,4% enfermeiros às vezes. Para o desbridamento, 16 (64% àsvezes utilizavam papaína e 15 (71,4% às vezes utilizavam colagenase. Em úlceras com tecido de granulaçãosempre era utilizado o soro fisiológico por 25 (100% enfermeiros. Houve variação nas práticas para otratamento da UP e falta de adesão às diretrizes.

Mortalidad por causas externas en Medellín, 1999-2006

Directory of Open Access Journals (Sweden)

Doris Cardona Arango

2008-01-01

Full Text Available Caracterizar el comportamiento de la mortalidad por causas externas en la ciudad de Medellín, Colombia, entre 1999-2006, según sexo, edad y causa básica de muerte fue el objetivo de este estudio descriptivo longitudinal, con fuente de información secundaria de 22 128 registros de defunción por causas externas. El análisis realizado es univariado y bivariado por sexo, grupos de edad y causa de muerte. Las causas externas registradas en el periodo fueron: 72.9 por ciento por homicidio; 15.3 por ciento, accidente de transporte; 7.3 por ciento, traumatismos; 4.2 por ciento, por suicidio, y por otras causas, 0.4 por ciento. La mayor tasa de mortalidad se presentó en el grupo de edad de 20 a 24 años (27.6 por cien mil habitantes, hecho que merece especial consideración por las implicaciones sociales, familiares y laborales que representa el fallecimiento de una persona en su etapa productiva.

Ultrasound evaluation of normal and abnormal fetuses: comparison of conventional, tissue harmonic, and pulse- inversion harmonic imaging techniques

International Nuclear Information System (INIS)

Ryu, Jeong Ah; Kim, Bohyun; Kim, Sooah; Yang, Soon Ha; Choi, Moon Hae; Ahn, Hyeong Sik

2003-01-01

To determine the usefulness of tissue harmonic imaging (THI) and pulse-inversion harmonic imaging (PIHI) in the evaluation of normal and abnormal fetuses. Forty-one pregnant women who bore a total of 31 normal and ten abnormal fetuses underwent conventional ultrasonography (CUS), and then THI and PIHI. US images of six organ systems, namely the brain, spine, heart, abdomen, extremities and face were compared between the three techniques in terms of overall conspicuity and the definition of borders and internal structures. For the brain, heart, abdomen and face, overall conspicuity at THI and PIHI was significantly better than at CUS (p < 0.05). There was, though, no significant difference between THI and PIHI. Affected organs in abnormal fetuses were more clearly depicted at THI and PIHI than at CUS. Both THI and PIHI appear to be superior to CUS for the evaluation of normal or abnormal structures, particularly the brain, heart, abdomen and face

A cross-sectional evaluation of computer literacy among medical students at a tertiary care teaching hospital in Mumbai (Bombay

Directory of Open Access Journals (Sweden)

T S Panchabhai

2011-01-01

Full Text Available Background: Computer usage capabilities of medical students for introduction of computer-aided learning have not been adequately assessed. Aim: Cross-sectional study to evaluate computer literacy among medical students. Settings and Design: Tertiary care teaching hospital in Mumbai, India. Materials and Methods: Participants were administered a 52-question questionnaire, designed to study their background, computer resources, computer usage, activities enhancing computer skills, and attitudes toward computer-aided learning (CAL. The data was classified on the basis of sex, native place, and year of medical school, and the computer resources were compared. The computer usage and attitudes toward computer-based learning were assessed on a five-point Likert scale, to calculate Computer usage score (CUS - maximum 55, minimum 11 and Attitude score (AS - maximum 60, minimum 12. The quartile distribution among the groups with respect to the CUS and AS was compared by chi-squared tests. The correlation between CUS and AS was then tested. Results: Eight hundred and seventy-five students agreed to participate in the study and 832 completed the questionnaire. One hundred and twenty eight questionnaires were excluded and 704 were analyzed. Outstation students had significantly lesser computer resources as compared to local students (P<0.0001. The mean CUS for local students (27.0±9.2, Mean±SD was significantly higher than outstation students (23.2±9.05. No such difference was observed for the AS. The means of CUS and AS did not differ between males and females. The CUS and AS had positive, but weak correlations for all subgroups. Conclusion: The weak correlation between AS and CUS for all students could be explained by the lack of computer resources or inadequate training to use computers for learning. Providing additional resources would benefit the subset of outstation students with lesser computer resources. This weak correlation between the attitudes

Insights to the effects of free cells on community structure of attached cells and chalcopyrite bioleaching during different stages.

Science.gov (United States)

Feng, Shoushuai; Yang, Hailin; Wang, Wu

2016-01-01

The effects of free cells on community structure of attached cells and chalcopyrite bioleaching by Acidithiobacillus sp. during different stages were investigated. The attached cells of Acidithiobacillus thiooxidans owned the community advantage from 14thd to the end of bioprocess in the normal system. The community structure of attached cells was greatly influenced in the free cells-deficient systems. Compared to A. thiooxidans, the attached cells community of Acidithiobacillus ferrooxidans had a higher dependence on its free cells. Meanwhile, the analysis of key biochemical parameters revealed that the effects of free cells on chalcopyrite bioleaching in different stages were diverse, ranging from 32.8% to 64.3%. The bioleaching contribution of free cells of A. ferrooxidans in the stationary stage (8-14thd) was higher than those of A. thiooxidans, while the situation was gradually reversed in the jarosite passivation inhibited stage (26-40thd). These results may be useful in guiding chalcopyrite bioleaching. Copyright © 2015 Elsevier Ltd. All rights reserved.

Apendicitis por Paracoccidioides brasiliensis

Directory of Open Access Journals (Sweden)

Ana Beatriz MUÑOZ URRIBARRI

2006-01-01

Full Text Available La paracoccidioidomicosis es la micosis más prevalente en Sudamérica. La forma aguda afecta el sistema fagocítico mononuclear de niños y personas inmunocomprometidas. El compromiso gastrointestinal es frecuente y su patogenia implica diseminación hematógena y linfática. La linfadenomegalia abdominal causa obstrucción intestinal y abdomen agudo. En este artículo damos a conocer el caso de un niño con compromiso gastrointestinal por apendicitis. Este es el primer caso reportado de apendicitis por esta patología. (Rev Med Hered 2006;17:58-60.

Diagnostic utility of carotid artery duplex ultrasonography in the evaluation of syncope: a good test ordered for the wrong reason.

Science.gov (United States)

Kadian-Dodov, Daniella; Papolos, Alexander; Olin, Jeffrey W

2015-06-01

Syncope refers to a transient loss of consciousness and postural tone secondary to cerebral hypoperfusion. Guidelines recommend against neurovascular testing in cases of syncope without neurologic symptoms; however, many pursue carotid artery duplex ultrasonography (CUS) due to the prognostic implications of identified cerebrovascular disease. Our objective was to determine the diagnostic utility of CUS in the evaluation of syncope and the identification of new or severe atherosclerosis with the potential to change patient management. We reviewed records of 569 patients with CUS ordered for the primary indication of syncope through an accredited vascular laboratory at an academic, urban medical centre. Findings on CUS, patient demographic, clinical and laboratory information, and medications within 6 months of the CUS exam were reviewed. Bivariate relationships between key medical history characteristics and atherosclerosis status (known vs. new disease) were examined. Among 495 patients with complete information, cerebrovascular findings could potentially explain syncope in 2% (10 patients). Optimization of cardiovascular risk factors would benefit patients with known (56.6%) and new atherosclerosis (33.5%) with suboptimal lipid control, (LDL > 70 in 42.2 and 34.9% respectively; LDL > 100 in 15.7 and 20.4%), and those not on high-intensity statin therapy (80 and 87.5%) or antiplatelet medications (13.2 and 50.6%). CUS is a low-yield diagnostic test in the evaluation of syncope, but it is useful in the diagnosis of atherosclerosis and identification of subjects who would benefit from optimal medical therapy. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

Tatuaje por amalgama. Reporte de un caso

Directory of Open Access Journals (Sweden)

Luis Fang Mercado

2012-01-01

Full Text Available El tatuaje por amalgama se origina por el depósito en el tejido conectivo subepitelial de fragmentos de amalgama resultado de procedimientos iatrogénicos por parte del operador. La profundidad a la que se encuentren albergados los residuos de este material influye en la presentación clínica de las lesiones. Radiográficamente se pueden identificar los fragmentos mientras tengan diámetros razonables; histológicamente se pueden observar las partículas de amalgama como gránulos oscuros, sólidos e irregulares dispuesto entre los haces de colágeno y vasos sanguíneos. Este artículo refiere el caso clínico de un paciente que presentó pigmentación por amalgama en mucosa vestibular, originada por una porción de amalgama usada como material obturador en una apicectomía del 11 realizada con anterioridad. Teniendo en cuenta las consideraciones clínicas y radiográficas se optó por realizar una segunda apicectomía con obturación retrógrada con MTA del 11. Durante el procedimiento quirúrgico se cureteó y adelgazó la cara interna del colgajo mucoperióstico para tratar de disminuir el grado de pigmentación.

Piratarias de gênero: experimentos estéticos queer-copyleft

Directory of Open Access Journals (Sweden)

Galindo, Dolores

2010-01-01

Full Text Available Neste ensaio exploramos a noção de piratarias de gênero, tendo como lócus de nossas reflexões experimentos estéticos que aliam os ativismos queer e copyleft. Na medida em que, nas sociedades ocidentais deste início de século, as dinâmicas de gênero encontram-se fortemente marcadas por códigos tecnobionormativos (conhecimentos, artefatos e tecnologias regulados por leis de propriedade intelectual e tecnológica torna-se possível o encontro entre ativismos que, em princípio, não possuíam uma plataforma comum de ação. Algumas piratarias que discutimos estão próximas da expertise dos hackers, outras simplesmente navegam à deriva. Mas, em ambos os casos, as piratarias questionam princípios de propriedade intelectual e tecnológica que se encontram presentes nas dinâmicas de gênero contemporâneas

Genes and pathways for CO2 fixation in the obligate, chemolithoautotrophic acidophile, Acidithiobacillus ferrooxidans, Carbon fixation in A. ferrooxidans

Directory of Open Access Journals (Sweden)

Esparza Mario

2010-08-01

Full Text Available Abstract Background Acidithiobacillus ferrooxidans is chemolithoautotrophic γ-proteobacterium that thrives at extremely low pH (pH 1-2. Although a substantial amount of information is available regarding CO2 uptake and fixation in a variety of facultative autotrophs, less is known about the processes in obligate autotrophs, especially those living in extremely acidic conditions, prompting the present study. Results Four gene clusters (termed cbb1-4 in the A. ferrooxidans genome are predicted to encode enzymes and structural proteins involved in carbon assimilation via the Calvin-Benson-Bassham (CBB cycle including form I of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO, EC 4.1.1.39 and the CO2-concentrating carboxysomes. RT-PCR experiments demonstrated that each gene cluster is a single transcriptional unit and thus is an operon. Operon cbb1 is divergently transcribed from a gene, cbbR, encoding the LysR-type transcriptional regulator CbbR that has been shown in many organisms to regulate the expression of RubisCO genes. Sigma70-like -10 and -35 promoter boxes and potential CbbR-binding sites (T-N11-A/TNA-N7TNA were predicted in the upstream regions of the four operons. Electrophoretic mobility shift assays (EMSAs confirmed that purified CbbR is able to bind to the upstream regions of the cbb1, cbb2 and cbb3 operons, demonstrating that the predicted CbbR-binding sites are functional in vitro. However, CbbR failed to bind the upstream region of the cbb4 operon that contains cbbP, encoding phosphoribulokinase (EC 2.7.1.19. Thus, other factors not present in the assay may be required for binding or the region lacks a functional CbbR-binding site. The cbb3 operon contains genes predicted to encode anthranilate synthase components I and II, catalyzing the formation of anthranilate and pyruvate from chorismate. This suggests a novel regulatory connection between CO2 fixation and tryptophan biosynthesis. The presence of a form II Rubis

Fast synthesis, formation mechanism, and control of shell thickness of CuS–polystyrene core–shell microspheres

International Nuclear Information System (INIS)

Zhao, Li-min; Shao, Xin; Yin, Yi-bin; Li, Wen-zhi

2012-01-01

Graphical abstract: Core–shell structure PSt/CuS were prepared using polystyrene which were modified by 3-methacryloxypropyltrimethoxysilane as template. The coating thickness of CuS can be controlled by the amount of 3-methacryloxypropyltrimethoxysilane and the UV–vis absorption intensity of PSt/CuS composite also changed with the coating thickness of CuS. Highlights: ► Core–shell structure PSt/CuS were prepared using silanol-modified polystyrene microspheres as template. ► The coating thickness of core–shell structure PSt/CuS can be controlled by a simple method. ► The UV–vis absorption intensity of PSt/CuS composite also changed with the coating thickness of CuS. -- Abstract: The silanol-modified polystyrene microspheres were prepared through dispersion polymerization. Then copper sulfide particles were grown on silanol-modified polystyrene through sonochemical deposition in an aqueous bath containing copper acetate and sulfide, released through the hydrolysis of thioacetamide. The resulting particles were continuous and uniform as characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fourier transform infrared, thermogravimetric analysis and UV–vis absorption spectroscopy were used to characterize the structure and properties of core–shell particles. The results showed the coating thickness of CuS shell can be controlled by the amount of silanol and the UV–vis absorption intensity of PSt/CuS composite also changed with the coating thickness of CuS.

Stereological Study on the Positive Effect of Running Exercise on the Capillaries in the Hippocampus in a Depression Model

Directory of Open Access Journals (Sweden)

Linmu Chen

2017-11-01

Full Text Available Running exercise is an effective method to improve depressive symptoms when combined with drugs. However, the underlying mechanisms are not fully clear. Cerebral blood flow perfusion in depressed patients is significantly lower in the hippocampus. Physical activity can achieve cerebrovascular benefits. The purpose of this study was to evaluate the impacts of running exercise on capillaries in the hippocampal CA1 and dentate gyrus (DG regions. The chronic unpredictable stress (CUS depression model was used in this study. CUS rats were given 4 weeks of running exercise from the fifth week to the eighth week (20 min every day from Monday to Friday each week. The sucrose consumption test was used to measure anhedonia. Furthermore, stereological methods were used to investigate the capillary changes among the control group, CUS/Standard group and CUS/Running group. Sucrose consumption significantly increased in the CUS/Running group. Running exercise has positive effects on the capillaries parameters in the hippocampal CA1 and DG regions, such as the total volume, total length and total surface area. These results demonstrated that capillaries are protected by running exercise in the hippocampal CA1 and DG might be one of the structural bases for the exercise-induced treatment of depression-like behavior. These results suggest that drugs and behavior influence capillaries and may be considered as a new means for depression treatment in the future.

One-pot, self-assembled hydrothermal synthesis of 3D flower-like CuS/g-C3N4 composite with enhanced photocatalytic activity under visible-light irradiation

Science.gov (United States)

Khan, Azam; Alam, Umair; Raza, Waseem; Bahnemann, D.; Muneer, M.

2018-04-01

Novel visible-light-driven 3D flower-like CuS/g-C3N4 composites have been synthesized by different wt% of CuS using hydrothermal method and characterized by standard analytical techniques such as XRD, FTIR, XPS, BET, UV-Vis DRS spectroscopy, SEM-EDS, and TEM. SEM and TEM analyses showed an intimate interfacial contact between flower-like CuS and g-C3N4 sheet. The synthesized composite materials (CuS/g-C3N4) showed excellent photocatalytic activity for the decolorization of methylene blue (MB) in aqueous suspension under visible-light irradiation, compared with pure CuS and g-C3N4. Among various composites of CuS/g-C3N4, 10 wt% of CuS showed highest photocatalytic activity for the decolorization of dye (MB). This remarkably improved photocatalytic performance of the synthesized materials could be attributed to the synergistic interaction between CuS and g-C3N4, leading to prolonged lifetime of photo-generated e- and h+ pair through the Z-scheme system. A probable Z-scheme mechanism explaining the origin of enhanced performance of the composite material has been proposed. This work not only provides a facile way to synthesize 3D flower-like heterostructure, but also renders rational design for the development of highly efficient Z-scheme photocatalytic systems.

Sonochemical synthesis of copper II sulfide nanoparticles and their use as radiolytic stabilizer in poly(methyl methacrylate) matrix

International Nuclear Information System (INIS)

Albuquerque, Marilia Cordeiro C. de; Aquino, Katia Aparecida da Silva; Araujo, Elmo S.

2011-01-01

Copper (II) sulfide (CuS) was synthesized by sonochemical method. Cu S crystals with hexagonal structure exhibit irregular particles with an average size in the range of 250-900 nm. Commercial Poly(methyl methacrylate) (PMMA) containing CuS nanoparticles (PMMA/Cu) at concentrations of 0.15; 0.30; 0.45 and 0.60 wt% were investigated. The samples were irradiated with gamma radiation ( 60 Co) at room temperature and air atmosphere. The viscosity-average molar mass (Mv) was measured for PMMA systems without nanoparticles and with nanoparticles. Decrease in molar mass observed when the systems were gamma irradiated reflect the random scission effects that take place in the main chain. Degradation index (DI) value was also obtained by viscosity analysis. DI results showed that the addition of CuS nanoparticles at 0.3 wt% into PMMA matrix decreased the number of main chain scissions at dose of 25 kGy and was calculated a protection of 50% in PMMA matrix. CuS nanoparticles act as free radical scavenger into gamma-irradiated PMMA systems. Changes in the infrared spectra of PMMA systems indicate that polymer molecules interact with CuS nanoparticles. Improvement of mechanical properties was found for PMMA/Cu films. An increase of 38% of Young's modulus value and a decrease of 22% on the elongation at break value were recorded for PMMA/Cu films exposed to gamma irradiation. (author)

An Exploratory Study of Cost Engineering in Axiomatic Design: Creation of the Cost Model Based on an FR-DP Map

Science.gov (United States)

Lee, Taesik; Jeziorek, Peter

2004-01-01

Large complex projects cost large sums of money throughout their life cycle for a variety of reasons and causes. For such large programs, the credible estimation of the project cost, a quick assessment of the cost of making changes, and the management of the project budget with effective cost reduction determine the viability of the project. Cost engineering that deals with these issues requires a rigorous method and systematic processes. This paper introduces a logical framework to a&e effective cost engineering. The framework is built upon Axiomatic Design process. The structure in the Axiomatic Design process provides a good foundation to closely tie engineering design and cost information together. The cost framework presented in this paper is a systematic link between the functional domain (FRs), physical domain (DPs), cost domain (CUs), and a task/process-based model. The FR-DP map relates a system s functional requirements to design solutions across all levels and branches of the decomposition hierarchy. DPs are mapped into CUs, which provides a means to estimate the cost of design solutions - DPs - from the cost of the physical entities in the system - CUs. The task/process model describes the iterative process ot-developing each of the CUs, and is used to estimate the cost of CUs. By linking the four domains, this framework provides a superior traceability from requirements to cost information.

La pintura vista por un pintor joven

Directory of Open Access Journals (Sweden)

Fuentes Pozo, Pedro

2000-01-01

Full Text Available Not available

El pintor se define a lo largo del tiempo como un artista en mutación influenciado por la sociedad de su momento y por su propio mundo interior Esto ha contribuido a la creación de distintos estilos pictóricos y a una evolución que conlleva la despreocupación por el aspecto formal en aras de una introspección al mundo interior En el cambio constante se refleja la búsqueda del artista que valida la intemporalidad del arte. Así, el verdadero artista sobrevive al aplauso o rechazo de la crítica, convirtiéndose en un verdadero hombre renancentista preocupado por el hallazgo del conocimiento universal.

Experiência inicial com terapia por pressão negativa por instilação em feridas complexas

Directory of Open Access Journals (Sweden)

Dimas André Milcheski

Full Text Available RESUMO Objetivo: relatar a experiência inicial com a terapia por pressão negativa por instilação em feridas complexas infectadas ou contaminadas. Métodos: a terapia por pressão negativa por instilação utilizada foi o V.A.C. Ulta com instilação Veraflo (Kinetic Concepts, Inc. O modo de operação foi contínuo com pressão sub-atmosférica ajustada em 125 mmHg por duas horas e instilação entre as pausas. O tempo de instilação foi de 20 minutos (tempo de contato do agente tópico com a ferida e a substância instilada foi solução salina padrão a 0,9%. Após obtenção de preparo adequado da ferida, ela foi coberta com enxerto ou retalho. Resultados: foram operados dez pacientes com feridas complexas contaminadas ou infectadas. O número médio de trocas da TPNi foi 1,4, o número médio total de cirurgias foi de 2,4, o intervalo até a cobertura da ferida foi de 6,3 dias e o intervalo até a alta foi de 11,4 dias. Conclusão: a comparação da terapia por pressão negativa por instilação com dois estudos prévios (controle histórico evidenciou um tempo de internação menor, favorecendo a TPNi. Este estudo teve um caráter inicial, fazendo-se necessário conduzir um trabalho randomizado e controlado para confirmar a eficácia desta terapia e verificar a sua custo-efetividade.

Neuropatia experimental por DDT: análise de nervo por microdissecção de fibras

Directory of Open Access Journals (Sweden)

Edison Matos Nóvak

1984-09-01

Full Text Available Estudou-se o nervo gênito-femural do rato albino submetido a intoxicação crônica por DDT, administrado por 180 dias na dose de 5 mg/kg de peso via oral. Os resultados mostraram proporção anormal de fibras tipo C, sendo sugerido ocorrer degeneração tipo axonal determinada pelo DDT.

Ptose palpebral causada por Paquidermoperiostose

Directory of Open Access Journals (Sweden)

Patricia Regina de Pinho Tavares

2014-08-01

Full Text Available A paquidermoperiostose é uma síndrome caracterizada por acometimento cutâneo e ósseo, e em alguns casos ocorre comprometimento palpebral leve. É uma síndrome rara, idiopática ou hereditária, com provável herança autossômica dominante de penetrância variável. Descreve-se o caso de um paciente com ptose grave por paquidermoperiostose elucidando sua fisiopatologia e conduta cirúrgica aplicada.

A expansão da pós-graduação em cenários de globalização: recortes da situação brasileira

OpenAIRE

Cabral Neto, Antonio; Castro, Alda Maria Duarte Araújo

2013-01-01

O artigo analisa o processo de globalização no contexto das inovações tecnológicas e suas repercussões no campo da educação. Discute a centralidade da produção do conhecimento para a competitividade das nações e o papel que a pós-graduação exerce enquanto lócus privilegiado de sua produção. Analisa a expansão desse nível educacional, no Brasil, nas últimas décadas, tomando por base os dados do GeoCapes. Conclui-se que a pós-graduação, nesse contexto de globalização, assume importância fulcral...

Shifts in microbial community composition and function in the acidification of a lead/zinc mine tailings.

Science.gov (United States)

Chen, Lin-Xing; Li, Jin-Tian; Chen, Ya-Ting; Huang, Li-Nan; Hua, Zheng-Shuang; Hu, Min; Shu, Wen-Sheng

2013-09-01

In an attempt to link the microbial community composition and function in mine tailings to the generation of acid mine drainage, we simultaneously explored the geochemistry and microbiology of six tailings collected from a lead/zinc mine, i.e. primary tailings (T1), slightly acidic tailings (T2), extremely acidic tailings (T3, T4 and T5) and orange-coloured oxidized tailings (T6). Geochemical results showed that the six tailings (from T1 to T6) likely represented sequential stages of the acidification process of the mine tailings. 16S rRNA pyrosequencing revealed a contrasting microbial composition between the six tailings: Proteobacteria-related sequences dominated T1-T3 with relative abundance ranging from 56 to 93%, whereas Ferroplasma-related sequences dominated T4-T6 with relative abundance ranging from 28 to 58%. Furthermore, metagenomic analysis of the microbial communities of T2 and T6 indicated that the genes encoding key enzymes for microbial carbon fixation, nitrogen fixation and sulfur oxidation in T2 were largely from Thiobacillus and Acidithiobacillus, Methylococcus capsulatus, and Thiobacillus denitrificans respectively; while those in T6 were mostly identified in Acidithiobacillus and Leptospirillum, Acidithiobacillus and Leptospirillum, and Acidithiobacillus respectively. The microbial communities in T2 and T6 harboured more genes suggesting diverse metabolic capacities for sulfur oxidation/heavy metal detoxification and tolerating low pH respectively. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations

Science.gov (United States)

Levicán, Gloria; Ugalde, Juan A; Ehrenfeld, Nicole; Maass, Alejandro; Parada, Pilar

2008-01-01

Background Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine sites in Chile was performed. This study demonstrated that there are important differences in the carbon dioxide and nitrogen fixation mechanisms among bioleaching bacteria that coexist in mining environments. Results In this study, we probed that both Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans incorporate CO2 via the Calvin-Benson-Bassham cycle; however, the former bacterium has two copies of the Rubisco type I gene whereas the latter has only one copy. In contrast, we demonstrated that Leptospirillum ferriphilum utilizes the reductive tricarboxylic acid cycle for carbon fixation. Although all the species analyzed in our study can incorporate ammonia by an ammonia transporter, we demonstrated that Acidithiobacillus thiooxidans could also assimilate nitrate and nitrite but only Acidithiobacillus ferrooxidans could fix nitrogen directly from the air. Conclusion The current study utilized genomic and molecular evidence to verify carbon and nitrogen fixation mechanisms for three bioleaching bacteria and provided an analysis of the potential regulatory pathways and functional networks that control carbon and nitrogen fixation in these microorganisms. PMID:19055775

Evaluation of uterine ultrasound imaging in cervical radiotherapy; a comparison of autoscan and conventional probe

DEFF Research Database (Denmark)

Baker, Mariwan; Cooper, David T.; Behrens, Claus F.

2016-01-01

.001). The median of the interobserver COM distance (Euclidean distance for 36 scans) was reduced from 8.5 (C-US) to 6.0mm (A-US). An F-test on the 36 scans showed strong significant differences (p Euclidean interobserver distance when comparing the C-US with the A-US scans. The average...

Suppression of cytochrome P450 reductase (POR) expression in hepatoma cells replicates the hepatic lipidosis observed in hepatic POR-null mice.

Science.gov (United States)

Porter, Todd D; Banerjee, Subhashis; Stolarczyk, Elzbieta I; Zou, Ling

2011-06-01

Cytochrome P450 reductase (POR) is a microsomal electron transport protein essential to cytochrome P450-mediated drug metabolism and sterol and bile acid synthesis. The conditional deletion of hepatic POR gene expression in mice results in a marked decrease in plasma cholesterol levels counterbalanced by the accumulation of triglycerides in lipid droplets in hepatocytes. To evaluate the role of cholesterol and bile acid synthesis in this hepatic lipidosis, as well as the possible role of lipid transport from peripheral tissues, we developed a stable, small interfering RNA (siRNA)-mediated cell culture model for the suppression of POR. POR mRNA and protein expression were decreased by greater than 50% in McArdle-RH7777 rat hepatoma cells 10 days after transfection with a POR-siRNA expression plasmid, and POR expression was nearly completely extinguished by day 20. Immunofluorescent analysis revealed a marked accumulation of lipid droplets in cells by day 15, accompanied by a nearly 2-fold increase in cellular triglyceride content, replicating the lipidosis seen in hepatic POR-null mouse liver. In contrast, suppression of CYP51A1 (lanosterol demethylase) did not result in lipid accumulation, indicating that loss of cholesterol synthesis is not the basis for this lipidosis. Indeed, addition of cholesterol to the medium appeared to augment the lipidosis in POR-suppressed cells, whereas removal of lipids from the medium reversed the lipidosis. Oxysterols did not accumulate in POR-suppressed cells, discounting a role for liver X receptor in stimulating triglyceride synthesis, but addition of chenodeoxycholate significantly repressed lipid accumulation, suggesting that the absence of bile acids and loss of farnesoid X receptor stimulation lead to excessive triglyceride synthesis.

Consanguinidad por isonimia en Salta

Directory of Open Access Journals (Sweden)

Albeza, María V.

2007-01-01

Full Text Available Se estimó el coeficiente de parentesco por isonimia para localidades de la Puna, Valle Calchaquí y Valle de Lerma, a fin de evaluar diferentes factores evolutivos que podrían estar afectando la composición genética de la población. A partir de los apellidos de las parejas consignadas en fuentes primarias de información, se estimó la isonimia conyugal o marital, el coeficiente total Ft y sus componentes Fr (inbreeding azaroso y Fn (inbreeding no azaroso. De las localidades estudiadas, en la Puna se ha detectado sólo una pareja isónima en una de ellas, en el Valle Calchaquí, tres y ninguna en el Valle de Lerma. Tanto en el Valle Calchaquí como en el de Lerma, se han estimado valores negativos de Ft, y en la Puna se registran los valores más elevados. En las localidades estudiadas no se cumple el supuesto de transmisión patrilineal de apellidos por lo que los valores de Fr y por ende de Ft podrían estar subestimados. Es por ello que sería necesario contar con información desde otras vertientes metodológicas para corroborar, complementar y manejar cuidadosamente el análisis de los datos y las conclusiones que se obtienen.

Nefrectomía simple por puerto único (LESS) asistida por robot (da Vinci)

OpenAIRE

CASTILLO C,OCTAVIO A; VIDAL M,IVAR; SEPÚLVEDA T,FRANCISCO

2011-01-01

Introducción: La cirugía mínimamente invasiva en urología avanza rápidamente y la cirugía laparo-endoscópica a través de puerto único (LESS) no es la excepción. Esta técnica por vía laparoscópica presenta mucha dificultad y requiere de un cirujano laparoscópico experimentado debido a la falta de triangulación y el cruce de los instrumentos. Los beneficios del sistema quirúrgico da Vinci® han sido introducidos recientemente en LESS. Presentamos dos casos de nefrectomía LESS asistida por robot....

Análisis de costos por ausentismo laboral atribuibles a licencias médicas por enfermedad. Hospital Nacional Arzobispo Loayza 2015

OpenAIRE

Jave Escalante, Gladys Lizeth

2015-01-01

Determina el costo generado por el ausentismo laboral atribuible a licencias médicas por enfermedad en el Hospital Nacional Arzobispo Loayza 2015. METODOLOGÍA: Estudio no experimental. La muestra estuvo conformada por 118 médicos asistenciales y personal de enfermería. Para el análisis de los costos se utilizó el costo de tiempo perdido del paciente, ingresos dejados de percibir por el hospital y descuento económico al trabajador. Además se realizó un análisis económico y de sensibilidad. ...

Indice por Materias

Directory of Open Access Journals (Sweden)

Montoya H Luz Marina

1982-09-01

Full Text Available Un índice es una lista de palabras o frases indicadores asociados que permite la ubicación de material al interior de un libro o una publicación, en este caso será por el nombre de la materia.

Exclusion and diagnosis of pulmonary embolism by a rapid ELISA D-dimer test and noninvasive imaging techniques within the context of a clinical model.

Science.gov (United States)

Michiels, J J; Pattynama, P M

2000-01-01

A negative rapid ELISA D-dimer test alone in out-patients with a low to moderate clinical probability (CP) on pulmonary embolism (PE) is predicted to safely exclude pulmonary embolism. The combination of a negative rapid ELISA D-dimer test and a low to moderate CP on PE followed by compression ultrasonography (CUS) for the detection of deep vein thrombosis (DVT) is safe and cost-effective as it reduces the need for noninvasive imaging techniques to about 50% to 60% of outpatients with suspected PE. A high probability ventilation-perfusion (VP) scan or a positive spiral CT consistent with PE and the detection of DVT by CUS are currently considered to be clear indications for anticoagulant treatment. Subsequent pulmonary angiography (PA) is the gold standard diagnostic strategy to exclude or diagnose PE in suspected outpatients with a negative CUS, a positive rapid ELISA D-dimer test, and a nondiagnostic VP scan or negative spiral CT to prevent overtreatment with anticoagulants. However, the willingness of clinicians and the availability of resources to perform PA is restricted, a fact that has provided an impetus for clinical investigators to search for alternative noninvasive strategies to exclude or detect venous thromboembolism (VTE). Serial CUS testing for the detection of DVT in patients with a low to moderate CP on PE and a nondiagnostic VP scan or negative spiral CT is predicted to be safe and will reduce the need for PA to less than 10% or even less than 5%. This noninvasive serial CUS strategy restricts the need for invasive PA to a minor group of patients (spiral CT and a high CP on PE. Prospective evaluations are warranted to implement and to validate the advantages and the disadvantages of the various combinations of noninvasive strategies and to compare serial CUS testing versus PA in randomized clinical management studies of outpatients with suspected pulmonary embolism.

Differential response of hippocampal subregions to stress and learning.

Directory of Open Access Journals (Sweden)

Darby F Hawley

Full Text Available The hippocampus has two functionally distinct subregions-the dorsal portion, primarily associated with spatial navigation, and the ventral portion, primarily associated with anxiety. In a prior study of chronic unpredictable stress (CUS in rodents, we found that it selectively enhanced cellular plasticity in the dorsal hippocampal subregion while negatively impacting it in the ventral. In the present study, we determined whether this adaptive plasticity in the dorsal subregion would confer CUS rats an advantage in a spatial task-the radial arm water maze (RAWM. RAWM exposure is both stressful and requires spatial navigation, and therefore places demands simultaneously upon both hippocampal subregions. Therefore, we used Western blotting to investigate differential expression of plasticity-associated proteins (brain derived neurotrophic factor [BDNF], proBDNF and postsynaptic density-95 [PSD-95] in the dorsal and ventral subregions following RAWM exposure. Lastly, we used unbiased stereology to compare the effects of CUS on proliferation, survival and neuronal differentiation of cells in the dorsal and ventral hippocampal subregions. We found that CUS and exposure to the RAWM both increased corticosterone, indicating that both are stressful; nevertheless, CUS animals had significantly better long-term spatial memory. We also observed a subregion-specific pattern of protein expression following RAWM, with proBDNF increased in the dorsal and decreased in the ventral subregion, while PSD-95 was selectively upregulated in the ventral. Finally, consistent with our previous study, we found that CUS most negatively affected neurogenesis in the ventral (compared to the dorsal subregion. Taken together, our data support a dual role for the hippocampus in stressful experiences, with the more resilient dorsal portion undergoing adaptive plasticity (perhaps to facilitate escape from or neutralization of the stressor, and the ventral portion involved in

An efficient chronic unpredictable stress protocol to induce stress-related responses in C57BL/6 mice

Directory of Open Access Journals (Sweden)

Susana eMonteiro

2015-02-01

Full Text Available Exposure to chronic stress can have broad effects on health ranging from increased predisposition for neuropsychiatric disorders to deregulation of immune responses. The chronic unpredictable stress (CUS protocol has been widely used to study the impact of stress exposure in several animal models and consists in the random, intermittent and unpredictable exposure to a variety of stressors during several weeks. CUS has consistently been shown to induce behavioral and immunological alterations typical of the chronic stress response. Unfortunately C57BL/6 mice, one of the most widely used mouse strains, due to the great variety of genetically modified lines, seem to be resistant to the commonly used 4-week-long CUS protocol. The definition of an alternative CUS protocol allowing the use of C57BL/6 mice in chronic stress experiments is a need. Here we show that by extending the CUS protocol to 8 weeks is possible to induce a chronic stress response in C57BL/6 mice, as revealed by abrogated body weight gain, increased adrenals weight and an overactive hypothalamic-pituitary-adrenal (HPA axis with increased levels of serum corticosterone. Moreover, we also observed stress-associated behavioral alterations, including the potentiation of anxious-like and depressive-like behaviors and a reduction of exploratory behavior, as well as subtle stress-related changes in the cell population of the thymus and of the spleen.The present protocol for C57BL/6 mice consistently triggers the spectrum of CUS-induced changes observed in rats and, thus, will be highly useful to researchers that need to use this particular mouse strain as an animal model of neuropsychiatric disorders and/or immune deregulation related to chronic unpredictable stress.

Mortalidad intrahospitalaria por accidente cerebrovascular

OpenAIRE

Federico Rodríguez Lucci; Virginia Pujol Lereis; Sebastián Ameriso; Guillermo Povedano; María F. Díaz; Alejandro Hlavnicka; Néstor A. Wainsztein; Sebastián F. Ameriso

2013-01-01

La mortalidad global por accidente cerebrovascular (ACV) ha disminuido en las últimas tres décadas, probablemente debido a un mejor control de los factores de riesgo vascular. La mortalidad hospitalaria por ACV ha sido tradicionalmente estimada entre 6 y 14% en la mayoría de las series comunicadas. Sin embargo, los datos de ensayos clínicos recientes sugieren que esta cifra sería sustancialmente menor. Se revisaron datos de pacientes internados con diagnóstico de ACV del Banco de Datos de Str...

Synthesis and properties of ternary (K, NH4, H3O)-jarosites precipitated from Acidithiobacillus ferrooxidans cultures in simulated bioleaching solutions

International Nuclear Information System (INIS)

Sandy Jones, F.; Bigham, Jerry M.; Gramp, Jonathan P.; Tuovinen, Olli H.

2014-01-01

The purpose of this study was to synthesize a series of solid solution jarosites by biological oxidation of ferrous iron at pH 2.2–4.4 and ambient temperature in media containing mixtures of K + (0, 1, 4, 6, 12, 31 mM) and NH 4 + (6.1, 80, 160, 320 mM). The starting material was a liquid medium for Acidithiobacillus ferrooxidans comprised of 120 mM FeSO 4 solution and mineral salts at pH 2.2. Following inoculation with A. ferrooxidans, the cultures were incubated in shake flasks at 22 °C. As bacteria oxidized ferrous iron, ferric iron hydrolyzed and precipitated as jarosite-group minerals (AFe 3 (SO 4 ) 2 (OH) 6 ) and/or schwertmannite (idealized formula Fe 8 O 8 (OH) 6 (SO 4 )·nH 2 O). The precipitates were characterized by X-ray diffraction (XRD), elemental analysis, and Munsell color. Schwertmannite was the dominant mineral product at low combinations of K + (≤ 4 mM) and NH 4 + (≤ 80 mM) in the media. At higher single or combined concentrations, yellowish jarosite phases were produced, and Munsell hue provided a sensitive means of detecting minor schwertmannite in the oxidation products. Although the hydrated ionic radii of K + and NH 4 + are similar, K + greatly facilitated the formation of a jarosite phase compared to NH 4 + . Unit cell and cell volume calculations from refinements of the powder XRD patterns indicated that the jarosite phases produced were mostly ternary (K, NH 4 , H 3 O)-solid solutions that were also deficient in structural Fe, especially at low NH 4 contents. Thus, ferric iron precipitation from the simulated bioleaching systems yielded solid solutions of jarosite with chemical compositions that were dependent on the relative concentrations of K + and NH 4 + in the synthesis media. No phase separations involving discrete, end-member K-jarosite or NH 4 -jarosite were detected in the un-aged precipitates. - Highlights: • Fe(III) precipitates formed in A. ferrooxidans culture solutions were characterized. • The monovalent cation

CARACTERÍSTICAS DA VIOLÊNCIA SEXUAL SOFRIDA POR CRIANÇAS ASSISTIDAS POR UM PROGRAMA DE APOIO

Directory of Open Access Journals (Sweden)

KELLY LINHARES VASCONCELOS

2010-01-01

Full Text Available En Brasil, las estadísticas de la violencia sexual contra niños están lejos de reflejar la verdadera realidad actual debido a la baja notificación de los casos. La finalidad de este estudio fue caracterizar el abuso sexual sufrido por niños asistidos por el Programa Sentinela y el perfil del agresor, en Sobral-Ceará, en el periodo que va del 2002 al 2006. La muestra no probabilística intencional fue compuesta por 50 víctimas de abuso sexual y de las mismas, el 66% es del sexo femenino, con predominio de rango de edad entre 8-12 años incompletos, (58%; en el 36% de los casos los padres están separados, siendo la madre la principal responsable por la familia (62%. La mayoría de los agresores es del sexo masculino (78%. En el ambiente fuera de la familia los agresores son conocidos o amigos de la familia (14%; dentro del seno familiar el padrastro es identificado como siendo el agresor más frecuente (18%. Los datos destacan características similares a las de otros estudios, definiendo una cierta igualdad en este tipo de violencia.

Sonochemical synthesis of copper II sulfide nanoparticles and their use as radiolytic stabilizer in poly(methyl methacrylate) matrix

Energy Technology Data Exchange (ETDEWEB)

Albuquerque, Marilia Cordeiro C. de; Aquino, Katia Aparecida da Silva; Araujo, Elmo S., E-mail: aquino@ufpe.b [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

2011-07-01

Copper (II) sulfide (CuS) was synthesized by sonochemical method. Cu S crystals with hexagonal structure exhibit irregular particles with an average size in the range of 250-900 nm. Commercial Poly(methyl methacrylate) (PMMA) containing CuS nanoparticles (PMMA/Cu) at concentrations of 0.15; 0.30; 0.45 and 0.60 wt% were investigated. The samples were irradiated with gamma radiation ({sup 60}Co) at room temperature and air atmosphere. The viscosity-average molar mass (Mv) was measured for PMMA systems without nanoparticles and with nanoparticles. Decrease in molar mass observed when the systems were gamma irradiated reflect the random scission effects that take place in the main chain. Degradation index (DI) value was also obtained by viscosity analysis. DI results showed that the addition of CuS nanoparticles at 0.3 wt% into PMMA matrix decreased the number of main chain scissions at dose of 25 kGy and was calculated a protection of 50% in PMMA matrix. CuS nanoparticles act as free radical scavenger into gamma-irradiated PMMA systems. Changes in the infrared spectra of PMMA systems indicate that polymer molecules interact with CuS nanoparticles. Improvement of mechanical properties was found for PMMA/Cu films. An increase of 38% of Young's modulus value and a decrease of 22% on the elongation at break value were recorded for PMMA/Cu films exposed to gamma irradiation. (author)

Vivencias psicosociales reveladas por niños que reciben tratamiento con quimioterapia por cáncer

Directory of Open Access Journals (Sweden)

BLANCA CECILIA VANEGAS DE AHOGADO

2009-12-01

Full Text Available Se realizó un estudio cualitativo con el propósito de descubrir las vivencias psicosociales de niños y niñas de 9 a 12 años que recibían tratamiento con quimioterapia por cáncer. La recolección de la información se hizo mediante encuentros lúdicos con el apoyo de algunas preguntas básicas que facilitaron las revelaciones narrativas. Tres aspectos se destacan en los hallazgos del estudio: vivencias desfavorables, vivencias relacionadas con la autoestima y vivencias favorables; las dos primeras, de diversa manera, afectan en estos niños su vida personal, familiar, escolar y, en general, todo su entorno. Es de resaltar que, como consecuencia de la caída del cabello, con frecuencia han sido objeto de burla y de rechazo por sus compañeros de estudio, lo que produce el más notorio efecto sobre su autoimagen; por otra parte, el ausentismo escolar conlleva dificultades académicas y sentimientos de tristeza en estos niños, situación que empeora cuando, por motivos de tratamiento, su lugar de residencia está alejado de la ciudad, viéndose sometidos a largos periodos de separación, no solo de su familia sino de sus pares. Se concluye que la mayor parte de las revelaciones son impactantes por su gran contenido de sufrimiento y dolor para estos niños, lo que demuestra la urgencia de retomar los hallazgos del estudio para orientar el cuidado de enfermería de manera más integral y apoyar para que se haga lo propio en el hogar y en las instituciones educativas.

Pedro Teixeira y su viaje por Mesopotamia

Directory of Open Access Journals (Sweden)

Fuente del Pilar, José Javier

2005-04-01

Full Text Available Pedro Teixeira es un integrante notable de la ilustre nómina de los viajeros portugueses que, a finales del s, XVI y principios del XVII, ensancharon para Occidente las fronteras del mundo. Su conocimiento en España se debe a la publicación en 1994 de su obra «Relaciones del Origen, Descendencia y Sucesión de los Reyes de Persia, y de Harmuz, y de un viaje hecho por el autor dende la India hasta Italia por tierra», en edición realizada por el profesor Eduardo Barajas Sala, lamentablemente fallecido en 1997. En este artículo se ofrece una reseña biográfica de Pedro Teixeira, y un análisis del viaje narrado por el autor en la última parte de sus «Relaciones »: el que desde Ormuz le conducirá, a través de Mesopotamia, hasta la costa del Mediterráneo.…

Violência e mortes por causas externas

Directory of Open Access Journals (Sweden)

Graciete Oliveira Vieira

2003-02-01

Full Text Available Através de um estudo ecológico caracterizou-se a violência e as mortes por causas externas em Salvador e Bahia utilizando-se dados da Fundação Nacional de Saúde-Ministério da Saúde, dos registros de mortalidade e das estimativas populacionais do IBGE. O risco de morrer por homicídio no Brasil é 3 vezes o do Estados Unidos, chegando a ser 40 vezes superior ao do Japão. Homicídio foi a primeira causa de anos potenciais de vidas perdidos (13,4% no Brasil (1997, seguido por acidentes de trânsito (10,6%. Causas externas foi a segunda causa de morte em Salvador e Bahia (1996. A violência tem raízes sócio-culturais e político-ideológicas e pode ser prevenida por ações intersetoriais e multidisciplinares.

Associação entre violência por parceiro íntimo contra a mulher e infecção por HIV

Directory of Open Access Journals (Sweden)

Claudia Barros

2011-04-01

Full Text Available OBJETIVO: Analisar a associação entre a violência por parceiro íntimo contra mulheres e a infecção ou suspeita de infecção pelo vírus da imunodeficiência humana (HIV. MÉTODOS: Estudo transversal com base em dados de questionários aplicados face-a-face e de prontuários médicos de 2.780 mulheres de 15 a 49 anos, atendidas em unidades do sistema único de saúde da Grande São Paulo, SP, em 2001-2002. As mulheres foram categorizadas em: usuárias em tratamento por serem "soropositivas para o HIV", com "suspeita de HIV" e aquelas que procuraram os serviços por outros motivos. A violência por parceiro íntimo contra mulheres na vida foi categorizada por gravidade e recorrência dos episódios de violência. A associação com o desfecho foi testada pelo modelo de Poisson com variância robusta e ajustada por variáveis sociodemográficas, sexuais e reprodutivas. RESULTADOS: A prevalência de violência foi de 59,8%. Sofrer violência reiterada e grave apresentou maior associação de infecção confirmada pelo HIV (RP = 1,91. A violência independente da gravidade e da recorrência dos episódios apresentou maior associação para a suspeita de infecção por HIV (RP = 1,29. CONCLUSÕES: A violência por parceiro íntimo contra mulheres tem papel relevante nas situações de suspeita e confirmação da infecção pelo HIV, sendo essencial incluir sua detecção, controle e prevenção como parte da atenção integral à saúde das mulheres.

Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations

Directory of Open Access Journals (Sweden)

Ehrenfeld Nicole

2008-12-01

Full Text Available Abstract Background Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine sites in Chile was performed. This study demonstrated that there are important differences in the carbon dioxide and nitrogen fixation mechanisms among bioleaching bacteria that coexist in mining environments. Results In this study, we probed that both Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans incorporate CO2 via the Calvin-Benson-Bassham cycle; however, the former bacterium has two copies of the Rubisco type I gene whereas the latter has only one copy. In contrast, we demonstrated that Leptospirillum ferriphilum utilizes the reductive tricarboxylic acid cycle for carbon fixation. Although all the species analyzed in our study can incorporate ammonia by an ammonia transporter, we demonstrated that Acidithiobacillus thiooxidans could also assimilate nitrate and nitrite but only Acidithiobacillus ferrooxidans could fix nitrogen directly from the air. Conclusion The current study utilized genomic and molecular evidence to verify carbon and nitrogen fixation mechanisms for three bioleaching bacteria and provided an analysis of the potential regulatory pathways and functional networks that control carbon and nitrogen fixation in these microorganisms.

Predominant porB1A and porB1B genotypes and correlation of gene mutations with drug resistance in Neisseria gonorrhoeae isolates in Eastern China

Directory of Open Access Journals (Sweden)

Tang Renxian

2010-11-01

Full Text Available Abstract Background Variations of porB1A and porB1B genes and their serotypes exist in Neisseria gonorrhoeae isolates from different geographical areas, and some site mutations in the porB1B gene correlate with drug resistance. Methods The β-lactamase production of N. gonorrhoeae isolates was determined by paper acidometric test and nitrocefin discs. The porB1A and porB1B genes of 315 non-penicillinase-producting N. gonorrhoeae (non-PPNG strains were amplified by PCR for sequencing to determine serotypes and site mutations. A duplex PCR was designed to simultaneously detect both porB1A and porB1B genes. Penicillin and tetracycline resistance was assessed by an in vitro drug sensitivity test. Results Of the N. gonorrhoeae isolates, 31.1% tested positive for porB1A and 68.9% for porB1B genes. All the 98 porB1A+ isolates belonging to IA6 serotype with either no mutation at the 120 and 121 sites (88.8% or a D120G (11.2% mutation and were no resistance to both penicillin and tetracycline. Among the 217 porB1B+ isolates, 26.7%, 22.6% and 11.5% belonged to IB3, IB3/6 and IB4 serotypes, respectively. Particularly, two novel chimeric serotypes, IB3/6-IB2 and IB2-IB4-IB2, were found in 77 and 8 porB1B+ isolates. Two hundred and twelve (97.7% of the porB1B+ isolates were presented G120 and/or A121 mutations with 163 (76.9% at both sites. Interestingly, within the 77 porB1B+ isolates belonging to IB3/6-IB2 serotype, 15 were discovered to possess novel deletions at both A121 and N122 sites. All the replacement mutations at these sites in PorB1B were correlated with resistance and the deletion mutation showed the highest resistance. Conclusion N. gonorrhoeae isolates circulating in Eastern China include a sole PorB1A serotype (IA6 and five PorB1B serotypes. Multiple mutations in porB1B genes, including novel A121 and N122 deletions, are correlated with high levels of penicillin and tetracycline resistance.

Conservación por calor

OpenAIRE

Cobos García, Angel; Díaz Rubio, Olga

2011-01-01

Esta unidade didáctica denominada Conservación por calor forma parte da materia «Tecnoloxía do procesado de alimentos» que se impartirá no primeiro semestre do 2º curso do Grao en Nutrición Humana e Dietética. A materia estrutúrase en diferentes unidades didácticas, tratando cada unha delas as diferentes tecnoloxías de procesado dos alimentos, tanto de conservación coma de transformación. A presente unidade didáctica aborda a conservación dos alimentos por calor. Este método permite destruír ...

Las cosas por su nombre

OpenAIRE

Storani, Emilia

2017-01-01

El artículo propone indagar sobre los modos y diferentes formatos que se utilizan tanto en la escritura como en la lectura, para articular con las luchas por la identidad de género. La Ley de Identidad de Género ha sido un puntapié clave para pensarnos a nosotros mismos culturalmente y para pensar a los demás. Pero, ¿cómo mencionamos, escribimos y leemos las diferentes identidades? La escritura, también es un mundo transformador para quienes bregan por una sociedad más libre y sin prejuicios....

Diverticulitis yeyunal perforada por enterolito.

OpenAIRE

Marenco De la Cuadra, Beatriz; Gomez-Rosado, Juan-Carlos; Capitan-Morales, Luis-Cristobal; Valdés Hernández, Javier; Reyes-lopera, N.J. De los

2012-01-01

La diverticulosis yeyunal es una enfermedad adquirida rara. Casi el 60-70% keeps asymptomátic or Con síntomas crónicos inespecíficos, aunque puede presentarse como un abdomen agudo. La perforación debida a enterolitos es una causa extremadamente rara do complicación, y puede producirse por la impactación de ésta contra la pared intestinal. Presentamos caso de un varón de 82 años que acude a urgencias por un dolor súbito abdominal, difuso, con irritación peritoneal, leucocitosis con neutro...

Por y para en los manuales de ELE

Directory of Open Access Journals (Sweden)

Sidoti, Rossana

2008-12-01

Full Text Available La oposición por / para es una de las cuestiones gramaticales que comportan mayor dificultad a la hora de acercarse al estudio del español como L2 sobre todo cuando remiten a conceptos lingüísticos difíciles de entender por no tener ésta referente alguno en el mundo extralingüístico. Si, por un lado, nos resulta fácil entender lo que tiene un referente en el mundo concreto; por otro, no podemos advertir el referente extralingüístico de preposiciones como por / para, si este no existe. Si las preposiciones son elementos abstractos, difíciles de aferrar de por sí, podemos sólo examinar los elementos que éstas ponen en relación y en qué contextos esta relación se determina. Para poder utilizar con precisión las dos preposiciones, es importante no reducirlas a una sola preposición como ocurre en otros idiomas, y sobre todo no relacionarlas sólo a los conceptos de causa y finalidad. Este trabajo se propone individualizar los manuales de español como lengua extranjera más utilizados en las universidades italianas para luego comparar las distintas fuentes de información sobre por / para y exponer comentarios, reflexiones y sugerencias sobre el tema con el fin de precisar en qué medida se puede mejorar lo que los manuales reducen o generalizan, puesto que para los estudiantes de ELE estos representan una herramienta valiosa a la que acudir.

Thermal Injury in Human Subjects Due to 94-GHz Radio Frequency Radiation Exposures

Science.gov (United States)

2016-02-24

1161902612 Digitally signed by JOHNSON.LELAND.R.1161902612 DN: c=US, o=U.S. Government, ou=DoD, ou= PKI , ou=USAF, cn=JOHNSON.LELAND.R.1161902612 Date...2016.03.07 15:07:11 -06󈧄’ POLHAMUS.GARR ETT.D.1175839484 Digitally signed by POLHAMUS.GARRETT.D.1175839484 DN: c=US, o=U.S. Government, ou=DoD, ou= PKI

Value of cystourethroscopy in the assessment of children with recurrent urinary tract infections and/or enuresis

DEFF Research Database (Denmark)

Nielsen, K K; Qvist, N; Kristensen, E S

1985-01-01

Forty-one children ages 6-14 years consecutively referred for recurrent urinary tract infections (RUTI) and/or enuresis constituted the study group. Cystourethroscopy (CUS) was carried out in 40 children and pathologic findings were revealed in 70% of children with RUTI in the absence of vesico...... patients with macroscopic haematuria during urinary tract infection were not managed differently following CUS....

Recombinant protein production data after expression in the bacterium Escherichia coli

Directory of Open Access Journals (Sweden)

J. Enrique Cantu-Bustos

2016-06-01

Full Text Available Fusion proteins have become essential for the expression and purification of recombinant proteins in Escherichia coli. The metal-binding protein CusF has shown several features that make it an attractive fusion protein and affinity tag: "Expression and purification of recombinant proteins in Escherichia coli tagged with the metal-binding protein CusF" (Cantu-Bustos et al., 2016 [1]. Here we present accompanying data from protein expression experiments; we tested different protein tags, temperatures, expression times, cellular compartments, and concentrations of inducer in order to obtain soluble protein and low formation of inclusion bodies. Additionally, we present data from the purification of the green fluorescent protein (GFP tagged with CusF, using Ag(I metal affinity chromatography.

Severity Stratification by Compression Ultrasound Examination in Lipodermatosclerosis and Diabetic Dermopathy Patients: a Report of Three Cases

Directory of Open Access Journals (Sweden)

Podoleanu Cristian

2017-06-01

Full Text Available Lipodermatosclerosis and diabetic dermopathy are low-risk skin lesions with many similar clinical features, except for venous abnormalities such as chronic venous insufficiency, but are rarely a reason for referring the patient to vascular ultrasound examination. We present 3 serial cases in which the compression ultrasound examination (CUS of the venous circulation of the affected limbs was of utmost importance in the severity stratification. Asymptomatic deep venous thrombosis (DVT was found in the first two cases, while in the third case the CUS excluded any type of vascular involvement, leading to a definite diagnosis of diabetic dermopathy. Lipodermatosclerosis may be associated with asymptomatic DVT due to chronic venous insufficiency, and early referral to CUS positively impacts further patient management.

Genetic diversity in soybean germplasm identified by SSR and EST-SSR markers Diversidade genética em germoplasma de soja identificada por marcadores SSR e EST-SSR

Directory of Open Access Journals (Sweden)

Bruno Mello Mulato

2010-03-01

órficos, e 259 alelos foram encontrados. O número de alelos por lócus variou entre 2-21, com média de 8,63. Os acessos possuem uma quantidade significativa de alelos raros, sendo os acessos 19, 35, 63 e 65 os que apresentaram maior número de alelos exclusivos. Os acessos 75 e 79 são os mais similares e os acessos 31 e 35, e 40 e 78 são os mais divergentes. Foi observada baixa correlação entre resultados de SSR e EST-SSR. Portanto, uma análise adequada de diversidade em soja deve ser feita utilizando-se tanto marcadores microssatélites genômicos como funcionais. A diversidade genética dos acessos selecionados é alta, tendo sido encontrados cinco grupos e vários subgrupos. Observou-se moderada relação entre divergência genética e origem geográfica dos acessos.

Pronóstico de la diarrea por rotavirus

Directory of Open Access Journals (Sweden)

Mota-Hernández Felipe

2001-01-01

Full Text Available Objetivo. Comparar la gravedad de la diarrea por rotavirus (RV y por no rotavirus. Material y métodos. Estudio transversal en 520 lactantes con diarrea aguda, efectuado entre octubre de 1994 y marzo de 1995 en siete centros del primer nivel de atención en cinco estados de México. El diagnóstico de RV se realizó con ensayo inmunoenzimático o por electroforesis. El análisis se hizo a través de medidas de tendencia central. Los resultados se presentan como promedio y desviación estándar o mediana o variación. Resultados. Se aisló RV en 264 lactantes (50.7% con predominio en varones de 6 meses a un año. Las manifestaciones clínicas fueron significativamente diferentes entre el grupo rotavirus positivo y el grupo rotavirus negativo en mediana de evacuaciones por 24 horas, frecuencia de vómitos, temperatura > 38° C, deshidratación y calificación de gravedad, respectivamente. Conclusiones. Estos resultados mostraron peor pronóstico por mayor gravedad de la diarrea por RV en lactantes, con relación a otra etiología. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.html

Miasis cutanea por cordylobia anthropophaga

Directory of Open Access Journals (Sweden)

Alkorta Gurrutxaga Miriam

2001-01-01

Full Text Available El incremento progresivo en el número de personas que viajan a países tropicales ha hecho que las enfermedades importadas adquieran una relevancia cada vez mayor. Las miasis (o infestaciones por larvas de moscas cutáneas se encuentran entre este tipo de enfermedades siendo especialmente frecuentes en países tropicales. A propósito de la observación de un caso de miasis cutánea masiva por Cordylobia antropophaga, que ocurrió en una mujer de 34 años de edad al volver de un viaje a Senegal, se ha efectuado una revisión de los casos de miasis cutáneas forunculoides importadas publicados en España, así como de la biología, patología, tratamiento y prevención de la miasis humana por Cordylobia anthropophaga. El caso referido, se caracterizó por la infestación con un número inusualmente elevado de larvas, no sospechándose su etiología hasta la fase final de la enfermedad. La emergencia continuada de larvas (se recogieron 91 generó en la paciente un estado de ansiedad importante. Finalmente, la eliminación de las larvas provocó una rápida mejoría de la paciente. Aunque los casos de miasis cutánea no tienen la gravedad de otras enfermedades importadas, su conocimiento es necesario desde el punto de vista preventivo, diagnóstico y terapeútico. Es importante proceder a la identificación morfológica de las larvas diferenciándolas de otro tipo de miasis con implicaciones terapéuticas diferentes.

Associação entre violência por parceiro íntimo contra a mulher e infecção por HIV Asociación entre violencia contra la mujer por pareja íntima e infección por VIH Association between intimate partner violence against women and HIV infection

Directory of Open Access Journals (Sweden)

Claudia Barros

2011-04-01

Full Text Available OBJETIVO: Analisar a associação entre a violência por parceiro íntimo contra mulheres e a infecção ou suspeita de infecção pelo vírus da imunodeficiência humana (HIV. MÉTODOS: Estudo transversal com base em dados de questionários aplicados face-a-face e de prontuários médicos de 2.780 mulheres de 15 a 49 anos, atendidas em unidades do sistema único de saúde da Grande São Paulo, SP, em 2001-2002. As mulheres foram categorizadas em: usuárias em tratamento por serem "soropositivas para o HIV", com "suspeita de HIV" e aquelas que procuraram os serviços por outros motivos. A violência por parceiro íntimo contra mulheres na vida foi categorizada por gravidade e recorrência dos episódios de violência. A associação com o desfecho foi testada pelo modelo de Poisson com variância robusta e ajustada por variáveis sociodemográficas, sexuais e reprodutivas. RESULTADOS: A prevalência de violência foi de 59,8%. Sofrer violência reiterada e grave apresentou maior associação de infecção confirmada pelo HIV (RP = 1,91. A violência independente da gravidade e da recorrência dos episódios apresentou maior associação para a suspeita de infecção por HIV (RP = 1,29. CONCLUSÕES: A violência por parceiro íntimo contra mulheres tem papel relevante nas situações de suspeita e confirmação da infecção pelo HIV, sendo essencial incluir sua detecção, controle e prevenção como parte da atenção integral à saúde das mulheres.OBJETIVO: Analizar la asociación entre la violencia contra mujeres por pareja íntima y la infección o sospecha de infección por el virus de inmunodeficiencia humana (VIH. MÉTODOS: Estudio transversal con base en datos de cuestionarios aplicados cara-a cara y de prontuarios médicos de 2.780 mujeres de 15 a 49 años, atendidas en unidades del sistema único de salud de la Gran Sao Paulo, Sureste de Brasil, en 2001-2002. Las mujeres fueron categorizadas en: usuarias en tratamiento por ser

Joint Bandwidth and Power Allocation for MIMO Two-Way Relays-Assisted Overlay Cognitive Radio Systems

KAUST Repository

Alsharoa, Ahmad; Ghazzai, Hakim; Yaacoub, Elias; Alouini, Mohamed-Slim; Kamal, Ahmed

2015-01-01

This paper studies the achievable cognitive sum rate of an overlay cognitive radio (CR) system assisted with multiple antennas two-way relays in which primary users (PUs) cooperate with cognitive users (CUs) for mutual benefits. In this context, the problem of both bandwidth and power allocation is investigated. We propose that the CUs are allowed to allocate a part of the PUs spectrum to perform their cognitive transmission. In return, acting as amplify-and-forward two-way relays, they are exploited to support PUs to reach their target data rates over the remaining bandwidth. Power expressions for optimal transmit power allocated per PU and CU antenna are derived under primary quality-of-service constraint in addition to bandwidth and power budget constraints. More specifically, CUs act as relays for the PUs transmission and gain some spectrum as long as they respect these constraints. After deriving the optimal transmit powers, we employ a strong optimization tool based on swarm intelligence to optimize the full and complex relay amplification gain matrices in addition to the bandwidths released to primary and cognitive transmission. Furthermore, three different utility functions are considered in our optimization problems depending on the level of fairness among CUs.

Bandwidth and power allocation for two-way relaying in overlay cognitive radio systems

KAUST Repository

Alsharoa, Ahmad M.

2014-12-01

In this paper, the problem of both bandwidth and power allocation for two-way multiple relay systems in overlay cognitive radio (CR) setup is investigated. In the CR overlay mode, primary users (PUs) cooperate with cognitive users (CUs) for mutual benefits. In our framework, we propose that the CUs are allowed to allocate a part of the PUs spectrum to perform their cognitive transmission. In return, acting as an amplify-and-forward two-way relays, they are used to support PUs to achieve their target data rates over the remaining bandwidth. More specifically, CUs acts as relays for the PUs and gain some spectrum as long as they respect a specific power budget and primary quality-of-service constraints. In this context, we first derive closed-form expressions for optimal transmit power allocated to PUs and CUs in order to maximize the cognitive objective. Then, we employ a strong optimization tool based on particle swarm optimization algorithm to find the optimal relay amplification gains and optimal cognitive released bandwidths as well. Our numerical results illustrate the performance of our proposed algorithm for different utility metrics and analyze the impact of some system parameters on the achieved performance.

Joint Bandwidth and Power Allocation for MIMO Two-Way Relays-Assisted Overlay Cognitive Radio Systems

KAUST Repository

Alsharoa, Ahmad

2015-10-08

This paper studies the achievable cognitive sum rate of an overlay cognitive radio (CR) system assisted with multiple antennas two-way relays in which primary users (PUs) cooperate with cognitive users (CUs) for mutual benefits. In this context, the problem of both bandwidth and power allocation is investigated. We propose that the CUs are allowed to allocate a part of the PUs spectrum to perform their cognitive transmission. In return, acting as amplify-and-forward two-way relays, they are exploited to support PUs to reach their target data rates over the remaining bandwidth. Power expressions for optimal transmit power allocated per PU and CU antenna are derived under primary quality-of-service constraint in addition to bandwidth and power budget constraints. More specifically, CUs act as relays for the PUs transmission and gain some spectrum as long as they respect these constraints. After deriving the optimal transmit powers, we employ a strong optimization tool based on swarm intelligence to optimize the full and complex relay amplification gain matrices in addition to the bandwidths released to primary and cognitive transmission. Furthermore, three different utility functions are considered in our optimization problems depending on the level of fairness among CUs.

Itinerarios Didácticos por la isla de Lanzarote

OpenAIRE

Becerra-Ramírez, Rafael; González Cárdenas, Elena; Gosálvez, Rafael U.; Escobar Lahoz, Estela; Dóniz-Páez, Javier

2013-01-01

Con la confección de esta guía de itinerarios didácticos por la isla de Lanzarote pretendemos contribuir a un mayor conocimiento de las características geográficas de este espacio dominado por las formas volcánicas que caracterizan un paisaje modificado por la mano del hombre que convive con los volcanes y los usa, tradicionalmente como soporte de sus cultivos, y modernamente como base de la industria turística. Los itinerarios didácticos por la isla de Lanzarote son la adaptación de los t...

Signos Vitales de los CDC-Muertes por intoxicación por alcohol (Alcohol Poisoning Deaths)

Centers for Disease Control (CDC) Podcasts

2015-01-06

Este podcast se basa en la edición de enero del 2015 del informe Signos Vitales de los CDC. En los Estados Unidos, mueren en promedio seis personas cada día debido a la intoxicación por alcohol. Infórmese sobre lo que puede hacer para prevenir los atracones de alcohol y las intoxicaciones por alcohol.  Created: 1/6/2015 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 1/6/2015.

Topoplastia de Cvintal assistida por laser de femtossegundo

Directory of Open Access Journals (Sweden)

Alexandre Takayoshi Ishizaki

2013-06-01

Full Text Available Apresentamos um relato de astigmatismo tardio progressivo pós-transplante de córnea para ceratocone, associado à afinamento periférico na junção doador-receptor, o que presumidamente pode ser considerado como recorrência da ectasia. O caso foi tratado por meio de Topoplastia de Cvintal assistida por laser de femtossegundo para a confecção da incisão com geometria "top hat", seguido de sutura com ajuste per-operatório guiado por ceratoscopia.

Micetoma por Nocardia brasiliensis: reporte de caso

Directory of Open Access Journals (Sweden)

Miriam Guevara R

2003-07-01

Full Text Available Se presenta el caso de un paciente peruano, agricultor, con una infección cutánea de origen traumático causada por Nocardia brasiliensis, que evolucionó hacia la amputación del miembro inferior afectado. El diagnóstico se realizó por examen directo y cultivo del espécimen.

Mortalidad por envenenamiento en niños

Directory of Open Access Journals (Sweden)

Híjar Martha

1998-01-01

Full Text Available Objetivo. Conocer el panorama de las muertes por envenenamiento en niños de 0-14 años ocurridas en la República mexicana, entre 1979 y 1994. Material y métodos. Se utilizaron fuentes secundarias. Las variables analizadas fueron: edad, sexo, año, causa externa de traumatismos y envenenamientos, de la IX Clasificación Internacional de Enfermedades: E850-E858, E860-E869 y E905. Mediante un modelo de regresión Poisson se analizaron tendencias por causa específica y se obtuvieron riesgos relativos según edad, sexo y entidad federativa. Resultados. Hubo un total de 11 272 defunciones en menores de 15 años; las principales causas fueron el envenenamiento y las reacciones tóxicas causadas por plantas y animales venenosos (E905, el envenenamiento accidental por gas de uso doméstico y por monóxido de carbono (E868 y el envenenamiento accidental por otras drogas (E858. El grupo de edad que presentó los mayores riesgos, para las causas mencionadas, fue el de menores de un año con un riesgo relativo (RR de 29.6, IC95% 29.2-33.4; RR 3.47, IC95% 2.86-4.22, y RR 31.86, IC95% 24.8-40.9. El riesgo fue similar en ambos sexos, salvo para la causa E905. El estado de Aguascalientes se situó sistemáticamente entre los de mayor riesgo para todas las causas analizadas, mientras que Nuevo León siempre se ubicó entre los de riesgo más bajo. Conclusiones. El envenenamiento constituye una importante causa de muerte en los niños; el riesgo se incrementa al disminuir la edad. Considerando que esas muertes son potencialmente evitables y que la mayor parte de los envenenamientos ocurren en el hogar, para prevenirlos, se recomienda a los familiares vigilar y mantener fuera de peligro al niño. Por otra parte, la multicausalidad del fenómeno requiere que su prevención se realice desde una perspectiva multidisciplinaria que genere una cultura y un ambiente de seguridad en la sociedad.

Enhanced performance of direct Z-scheme CuS-WO 3 system towards photocatalytic decomposition of organic pollutants under visible light

Energy Technology Data Exchange (ETDEWEB)

Song, Chundong; Wang, Xiang; Zhang, Jing; Chen, Xuebing; Li, Can

2017-12-01

CuS-WO₃ composites were synthesized by an in situ solution method at low temperature. The crystalline phase, morphology, particle size, and the optical properties of CuS-WO₃ samples were characterized by XRD, SEM, XPS, and UV–vis diffuse reflectance spectra. CuS-WO₃ composites showed much higher activity for photocatalytic degradation of RhB as compared with WO₃ and CuS. The degradation rate constant over 1 wt% CuS-WO₃ catalyst was 4.4 times and 9.2 times higher than that of WO₃ and CuS, respectively. It is found that holes (h+) and superoxide radical anions (O2-) are the dominant reactive species by using methanol, disodium ethylenediaminetetraacetate (EDTA) and ascorbic acid as scavengers. Band structure analysis shows that bottom of CB of WO₃ is very similar with and higher (ca. 0.01 eV) than the top of VB of CuS. The results of PL showed that the similarity renders the recombination between photogenerated holes on the VB of CuS and photogenerated electrons on the CB of WO₃ possible and easy, forming a direct Z-scheme in CuS-WO₃. This result in that more electrons in the CB of CuS and holes in the VB of WO₃ survived, and then participated in the photocatalytic degradation of RhB, showing an increased activity.

Community unit performance: factors associated with childhood diarrhea and appropriate treatment in Nyanza Province, Kenya

Directory of Open Access Journals (Sweden)

Yoshito Kawakatsu

2017-02-01

Full Text Available Abstract Background The government of Kenya launched its community health strategy in 2006 to improve certain aspects of its community health program. Under the strategy, community units (CUs were established as level one of the Kenyan health system. A core member at this level is the community health worker (CHW. The objective of this study was to assess the relationship among the performance of the CUs, the prevalence of childhood diarrhea and appropriate treatment for it by controlling individual and community-level factors. Methods The main dataset used in this study was the 2011 Nyanza Province county-based Multiple Indicator Cluster Survey (MICS. In addition, based on the list of community units in Nyanza Province, Kenya, we identified the area’s CUs and their performance. MICS data and data on CUs were merged using sub-location names. There were 17 individual and two community-level independent variables in this study. Bivariate analysis and a multilevel logistic regression were performed. Results Factors significantly associated with a lower prevalence of diarrhea among children under five were the child’s increasing age, middle-aged household heads, children who received more attention, water treatment and rural versus urban area residence, while male children and highly performing CUs were significantly associated with a higher prevalence of diarrhea. In addition, middle wealth index, severity of diarrhea and middle- and high-CU performance were significantly associated with appropriate treatment for childhood diarrhea. Conclusions Although this study found that children living in areas of high CU performance were more likely to have diarrhea, these areas would have been identified as being more at risk for diarrhea prevalence and other health concerns, prioritized for the establishment of a CU and allocated more resources to improve the performance of CUs. A higher CU performance was significantly associated with the appropriate

Community unit performance: factors associated with childhood diarrhea and appropriate treatment in Nyanza Province, Kenya.

Science.gov (United States)

Kawakatsu, Yoshito; Tanaka, Junichi; Ogawa, Kazuya; Ogendo, Kenneth; Honda, Sumihisa

2017-02-16

The government of Kenya launched its community health strategy in 2006 to improve certain aspects of its community health program. Under the strategy, community units (CUs) were established as level one of the Kenyan health system. A core member at this level is the community health worker (CHW). The objective of this study was to assess the relationship among the performance of the CUs, the prevalence of childhood diarrhea and appropriate treatment for it by controlling individual and community-level factors. The main dataset used in this study was the 2011 Nyanza Province county-based Multiple Indicator Cluster Survey (MICS). In addition, based on the list of community units in Nyanza Province, Kenya, we identified the area's CUs and their performance. MICS data and data on CUs were merged using sub-location names. There were 17 individual and two community-level independent variables in this study. Bivariate analysis and a multilevel logistic regression were performed. Factors significantly associated with a lower prevalence of diarrhea among children under five were the child's increasing age, middle-aged household heads, children who received more attention, water treatment and rural versus urban area residence, while male children and highly performing CUs were significantly associated with a higher prevalence of diarrhea. In addition, middle wealth index, severity of diarrhea and middle- and high-CU performance were significantly associated with appropriate treatment for childhood diarrhea. Although this study found that children living in areas of high CU performance were more likely to have diarrhea, these areas would have been identified as being more at risk for diarrhea prevalence and other health concerns, prioritized for the establishment of a CU and allocated more resources to improve the performance of CUs. A higher CU performance was significantly associated with the appropriate treatment. It was suggested that CHWs could have a positive effect on

Selección de Recursos Humanos por Competencias

OpenAIRE

Sánchez Domingo, Cristina

2013-01-01

Los objetivos de este trabajo son, por un lado conocer en qué consisten los procesos de valoración y selección de personas desde el enfoque de las competencias laborales. Para ello, ha sido preciso profundizar en el estudio del concepto de “competencia laboral”, y comprender qué es la Gestión de Recursos Humanos por Competencias, en cuyo seno se encuentra la propia Selección de Recursos Humanos. Por otra parte, un segundo objetivo del trabajo es conocer el grado de implantación de la Selecció...

Tallado de hélices por el método de copiado por proyección

Directory of Open Access Journals (Sweden)

José Vicente Fierro Vasco

1983-01-01

Full Text Available Este dispositivo fue diseñado como parte de la investigación sobre Aerogeneradores que se está llevando a cabo en el Departamento de Ingeniería Mecánica, cuyo investigador principal es el Ing. Julio Mario Rodríguez Devis. Como parte inicial de la investigación se adecuó un túnel situado en el Laboratorio de Hidráulica para hacer las pruebas de modelos. En la construcción de dichos modelos se requiere una buena precisión en la hechura de las aspas del molino, en especial por el tamaño reducido de liste. Se debe garantizar que el perfil aerodinámico se conserve a lo largo del aspa, por lo que se requiere de un dispositivo capaz de tallar los álabes con la precisión y rapidez necesarias. Los resultados del trabajo fueron presentados al concurso del premio Worthington de la Ingeniería Colombiana 1982 (Categoría estudiantes, por los estudiantes que trabajaron en el proyecto, siendo acreedores al primer puesto.

CARACTERIZAÇÃO ESPECTRAL DA CANA-DE-AÇÚCAR INFECTADA POR NEMATOIDES E MIGDOLUS FRYANUS POR ESPECTRORRADIOMETRIA DE CAMPO

Directory of Open Access Journals (Sweden)

George Deroco Martins

Full Text Available O cultivo da cana-de-açúcar no Brasil, embora assistido por técnicas modernas de plantio, é alvo constante de parasitas do sistema radicular. Por registrar seletivamente o fluxo espectral da radiação eletromagnética refletida pela vegetação, o sensoriamento remoto tornou-se uma poderosa ferramenta na detecção das plantas infectadas por patógenos do solo. Com o objetivo de caracterizar espectralmente a cana-de-açúcar sadia e infectada por nematoides e pela larva do besouro Migdolus fryanus, foram tomadas medidas radiométricas in situ e geradas curvas hiperespectrais de plantas sadias e infectadas. Técnicas específicas de análise espectral, como a determinação da posição da borda do vermelho limítrofe (Red Edge Position Determination - REPD e diferentes índices espectrais foram avaliados para discriminar as três ocorrências. As curvas de reflectância mostraram diferenças em magnitude principalmente nos comprimentos de onda do vermelho e infravermelho próximo e, assim como a determinação do REP e os índices de clorofila b, NDVI, MCARI e TCARI, permitiram distinguir apenas entre plantas sadias e infectadas. As razões espectrais sensíveis aos pigmentos clorofila a e carotenoides, porém, discriminaram as três ocorrências, inclusive plantas infectadas por nematoides e Migdolus fryanus. A melhor discriminação foi obtida com o índice de carotenoides, um pigmento fortemente relacionado com estresse da planta

Osteoporosis secundaria y Osteoporosis inducida por glucocorticoides (OIG

Directory of Open Access Journals (Sweden)

Elías Forero Illera

2006-01-01

Full Text Available La osteoporosis es un problema de salud pública importante a nivel mundial, y su prevalencia está aumentando. La osteoporosis secundaria se puede producir por varias patologías y el uso de ciertos medicamentos. Los glucocorticoides son un grupo de fármacos usados extensamente en la práctica médica debido a su indiscutible utilidad. La osteoporosis inducida por glucocorticoides es un problema de salud pública. Aunque la patogénesis de la pérdida producida por los glucocorticoides en el hueso no se conoce totalmente, investigaciones recientes han proporcionado nuevas conocimientos en los mecanismos de estos fármacos a nivel celular y molecular. Diversas guías han sido propuestas por diversos grupos para el tratamiento de la OIG; desafortunadamente, las guías del tratamiento no se utilizan adecuadamente en los pacientes.

Principais gestos esportivos executados por jogadores de handebol

Directory of Open Access Journals (Sweden)

Luiz Carlos Hespanhol Junior

2012-09-01

Full Text Available Este estudo teve como objetivo quantificar os principais gestos esportivos executados por jogadores profissionais de handebol. Para a mensuração quantitativa dos principais movimentos executados por cada jogador de handebol avaliado foram realizadas gravações de vídeo em todos os jogos. Foram realizados em média 1288,0 (DP = 190,7 gestos esportivos por jogo. Os armadores centrais realizaram em média 375,0 (DP = 83,7 gestos esportivos, e a posição de pivô 63,3 (DP = 21,2 gestos por jogo. As recepções e os passes foram os gestos mais executados, e a posição que mais realizou gestos esportivos na equipe de handebol avaliada foi o armador central, seguido do armador esquerdo e direito. O pivô foi a posição que menos realizou gestos esportivos.

Higiene mental: conferencia dictada por la Radiodifusora Nacional

Directory of Open Access Journals (Sweden)

Francisco Gómez Pinzón

1941-01-01

tiene extraordinaria trascendencia para el país por sus vastas repercusiones sobre el futuro de nuestro pueblo, y que, sin embargo ha sido negligentemente olvidado por las autoridades y deliberadamente ignorado por los sectores cultos e ilustrados de nuestra sociedad. Me refería entonces a la curva ascendente que, no sólo entre nosotros sino en todos los países civilizados, han seguido en su propagación las enfermedades nerviosas y mentales, y que hace contraste con la disminución progresiva de las demás afecciones y en especial de las infecto-contagiosas, que están a punto de ser dominadas por la técnica cada día más perfecta de la medicina preventiva. Hoy quiero ocuparme de algunos aspectos de este mismo tema que apenas alcanzaron a ser esbozados en mi conferencia anterior.

La mortalidad por enfermedades del corazón y por reumatismo en la ciudad de bogotá

OpenAIRE

Bejarano, Jorge

2012-01-01

La alta cifra de mortalidad por enfermedades cardio-vasculares está indicando la urgencia de una campana para contener sus avances. De todas las adquisiciones sanitarias, ninguna ha tenido el alcance y los resultados admirables de los centros o dispensarios destinados al tratamiento de una enfermedad y a la educación del enfermo. Nadie podrá pues, dudar que los dispensarios o consultorios de enfermedades cardio-vasculares, sea una de las armas más eficaces en la lucha contra la mortalidad por...

Levantamiento del proceso de registros contables por causación de las cuentas por cobrar a clientes

OpenAIRE

Mayele-Rodríguez, Luz

2013-01-01

De igual forma el Proyecto de Mejora de Procesos a elaborar, desarrollar e implementar en el Área Administrativa y Financiera del Centro de Pinturas Automotriz “LMS”, es realizar el levantamiento del Proceso de Registros Contables por Causación de las cuentas por cobrar a clientes. Lo anterior se puede desarrollar a partir de un poder de negociación con proveedores que incluye entre otros los siguientes factores : El plazo alcanzado en la negociación de compras de insumos, materias primas, co...

Alarma activada por control remoto selectivo.

OpenAIRE

Eguíluz Morán, Luis Ignacio; Lara Santillán, Pedro María; Mañana Canteli, Mario

1995-01-01

La finalidad de esta invención consiste en disponer de una alarma que bien evite el robo de objetos ligeros y portátiles por el procedimiento que se conoce como "del tirón" --es decir, arrebatar algo y salir corriendo--, bien permita identificar un equipaje entre otros. La originalidad del dispositivo reside en la activación/desactivación del dispositivo de sonido por control remoto, así como la posibilidad de seleccionar el sonido de salida dependiendo de su finalidad. Se reivindica como de ...

San Sebastian, vista por Paret y Alcázar

Directory of Open Access Journals (Sweden)

María Castilla Albisu

2013-07-01

Full Text Available Luis Paret y Alcázar pintó una serie de vistas panorámicas de puertos del litoral Cantábrico, por encargo del rey Carlos III. El objetivo de este trabajo es ahondar en la vida de este pintor para así comprender mejor su obra. A pesar de los estudios realizados por algunos historiadores quedan todavía incógnitas por descubrir relativas a la vida y al trabajo de este artista. Al acercarse a la figura de Paret y Alcázar hay que preguntarse por qué habiendo sido uno de los pintores más prometedores de su tiempo, su figura ha caído en un triste olvido.

Trisegmentectomia hepática direita por videolaparoscopia

Directory of Open Access Journals (Sweden)

Marcel Autran C. Machado

Full Text Available INTRODUÇÃO: Em 2007 os autores descreveram a primeira hepatectomia direita por videolaparoscopia realizada no Brasil. Hepatectomia direita ampliada, também conhecida como trisegmentectomia direita, é procedimento altamente complexo e implica em grande retirada do volume hepático. Os autores descrevem a primeira trisegmentectomia direita por videolaparoscopia realizada no Brasil. TÉCNICA: O paciente é colocado em posição supina em decúbito lateral esquerdo. O cirurgião se coloca entre as pernas da paciente. Utilizamos cinco trocartes, três de 12 mm e dois de 5 mm. Devido à embolização prévia da veia porta direita, o hilo hepático não é dissecado. O pedículo portal direito é seccionado com grampeador laparoscópico de carga vascular por meio de acesso intra-hepático, segundo técnica previamente descrita pelos autores. A seguir procede-se a mobilização do fígado direito seguido de dissecção da veia cava retro-hepática e secção da veia hepática direita. Estes passos são realizados sem manobra de Pringle. O fígado é seccionado com combinação de bisturi harmônico e grampeador endoscópico. O pedículo do segmento 4 é seccionado dentro do fígado. O espécime é retirado por meio de incisão supra-púbica e a área cruenta é revista para verificar hemostasia. O procedimento é encerrado e dreno de sistema fechado é posicionado junto à área cruenta. CONCLUSÃO: Trisegmentectomia hepática direita por videolaparoscopia é procedimento factível e seguro e deve ser considerado para pacientes selecionados. Este procedimento deve ser realizado em centros especializados e por cirurgiões com experiência tanto em cirurgia hepática como cirurgia laparoscópica avançada.

Análisis Competitivo por parte de los talleres de servicio automotriz, mediante el uso del valor percibido por el cliente

Directory of Open Access Journals (Sweden)

Jaime Baby Moreno

2015-06-01

Full Text Available Este artículo trata del uso del Valor Percibido por el Cliente (VPC como herramienta para el análisis competitivo por parte de talleres de reparación y mantenimiento automotriz. Se muestra cómo se determinan tanto la importancia relativa de los atributos que los compradores tienen en cuenta para evaluar el desempeño de un taller automotriz, como la evaluación de desempeño, realizada por los compradores de los "Talleres de los concesionarios" y de aquellos que son propiedad de individuos. Posteriormente, se ilustra la manera como unos y otros visualizan su posición competitiva. También muestra la brecha entre los valores ideales esperados y los percibidos por el mercado, la cual se constituye en una especie de "mapa" de oportunidades para las firmas actualmente presentes en el mercado y para nuevos participantes.

Malnutrición por defecto de un recién nacido por psicosis puerperal materna: presentación de un caso

OpenAIRE

Gavilla González, Bárbara; Díaz Cabrera, Leticia

2011-01-01

En el siguiente trabajo se realizó el seguimiento de un niño desde la etapa de recién nacido hasta el año de edad por malnutrición por defecto, de causa materna por psicosis puerperal. En este caso, la madre rechazaba a su hijo, negándose a alimentarlo, privando al bebé de algo tan importante en esta etapa de la vida como la lactancia materna exclusiva, requiriendo de alimentación complementaria en edad temprana para lograr un aumento de peso adecuado y un desarrollo psicomotor que se igualar...

Malnutrición por defecto de un recién nacido por psicosis puerperal materna: presentación de un caso

OpenAIRE

Gavilla González, Bárbara; Díaz Cabrera, Leticia

2012-01-01

En el siguiente trabajo se realizó el seguimiento de un niño desde la etapa de recién nacido hasta el año de edad, por malnutrición por defecto, de causa materna por psicosis puerperal. En este caso, la madre rechazaba a su hijo, negándose a alimentarlo, privando al bebé de algo tan importante en esta etapa de la vida como la lactancia materna exclusiva, requiriendo de alimentación complementaria en edad temprana para lograr un aumento de peso adecuado y un desarrollo psicomotor que se iguala...

Transmisión de Anaplasma marginale por garrapatas

Directory of Open Access Journals (Sweden)

Kelly A. Brayton

2012-01-01

Full Text Available Anaplasma marginale, patógeno de distribución mundial, es transmitido por garrapatas Ixódidas. Comprender su complejo desarrollo dentro de la garrapata vector, permitirá la predicción de brotes y ofrecerá oportunidades para controlar su transmisión. En este trabajo se revisa su ciclo básico de desarrollo junto con los estudios recientes acerca de las diferencias de transmisión entre cepas, que delinean aspectos de la interacción patógeno - vector. Bacterias, virus o protozoarios transmitidos por artrópodos causan enfermedades severas, tanto en humanos como en animales. Las enfermedades infecciosas transmitidas por garrapatas, entre las que incluimos a la Anaplasmosis (A. marginale, babesiosis (Babesia bigemina, B. bovis, B. divergens y Theileriosis (Theileria annulata, T. parva, se encuentran entre las más importantes en el ámbito mundial, con pérdidas cercanas a los siete mil millones de dólares anualmente; y, a pesar de su impacto, permanecen escasamente bajo control, basado primordialmente en la aplicación de acaricidas, para interrumpir su transmisión. La aparición de garrapatas resistentes a múltiples sustancias acaricidas, representa una amenaza en este tipo de control y, como resultado, hay un resurgimiento de la investigación para el desarrollo de nuevas estrategias para su control. Nuevas opciones para prevenir la transmisión de patógenos de animales por garrapatas, será el resultado de entender las interacciones garrapata patógeno; proceso que culmina con el desarrollo de la infección y transmisión exitosa. En todos los casos de patógenos transmitidos por garrapatas, el desarrollo de la infección se realiza coordinamente a los momentos de adhesión y alimentación del vector sobre el animal. Esto sucede por la interdependencia en la señalización entre el patógeno y el vector al alimentarse y, por ello, será susceptible de intervención.

Del significado responsabilidad de los socios en las compañías mercantiles por acciones y por cuotas.

Directory of Open Access Journals (Sweden)

Jorge Payome Suárez

2003-01-01

Full Text Available El comentario presentado, además de constituir una guía útil para los socios de compañías mercantiles por acciones y por cuotas, en un aspecto de indudable importancia para ellos, cual es el de su eventual responsabilidad, se erige como una herramienta provechosa para estudiantes y profesionales interesados en el tema. La experiencia académica y docente del autor del ensayo aseguran un análisis autorizado de la materia.

Consumo Voluntario de Forraje por Rumiantes en Pastoreo Consumo Voluntario de Forraje por Rumiantes en Pastoreo

Directory of Open Access Journals (Sweden)

José Mejía Haro

2012-02-01

Full Text Available The variation in voluntary forage intake is undoubtedly the major dietary factor determining level and efficiency of ruminant production. This variation is bigger and least predictable for grazing ruminants. Range ruminant productivity and efficiency is relatively low due, partly, to intake limitations; productivity could probably be increased most by increasing intake. Distension of the reticulo-rumen wall is the primary intake regulation mechanism of low-quality roughages in range ruminants, digestibility and rate of ingest passage also affect voluntary intake. Body size and metabolic bodysize as well affect intake of grazing animals. Kind and amount of supplementation, forage availability, and grazing intensity have been related to voluntary forage intake. La variación en el consumo voluntario de forraje es indudablemente el principal factor dietario que determina el nivel y eficiencia de producción en un rumiante. Esta variación es mayor y muy difícil de predecir bajo condiciones de pastoreo. La productividad y eficiencia de rumiantes en pastoreo es relativamente baja debido, en parte, a las limitaciones en el consumo; la productividad probablemente se podrá incrementar si se incrementa el consumo. La distensión de la pared del rumenretículo es el principal mecanismo de regulación del consumo de forrajes de baja calidad en rumiantes en pastoreo, aunque la digestibilidad y la tasa de pasaje también afectan el consumo voluntario. Igualmente, el consumo se ve afectado por el tamaño corporal y peso metabólico del animal, por la cantidad y tipo de suplemento ofrecido, por la disponibilidad de forraje y por la intensidad del pastoreo.

Evaluación del riesgo ambiental por metales pesados, generados por la actividad minera artesanal en los ríos Quiroz y Chira – Piura por el método de especiación secuencial

OpenAIRE

Loaiza Choque, Leonardo Edwin

2016-01-01

Determina el riesgo ambiental que representan los metales pesados dispuestos en los sedimentos de los ríos Quiroz y Chira ubicados en el departamento de Piura generados por la minería artesanal. Determina las formas químicas en las que se dispersan los metales pesados ambos ríos. Demuestra que el estudio por extracción secuencial puede ser usado como componente de herramienta de gestión ambiental. Realiza el análisis de extracción secuencial por el método BCR el mismo que permite determinar l...

Retinitis por citomegalovirus en un paciente con VIH

Directory of Open Access Journals (Sweden)

Alena de los Ángeles Vejerano Duany

Full Text Available La retinitis por citomegalovirus es la infección ocular más frecuente en pacientes con un recuento de linfocitos CD4 inferior a 200 por µL. El aspecto oftalmoscópico de las lesiones se caracteriza, en la mayoría de los casos, por infiltrados retinianos resultados de la necrosis retiniana producida por citomegalovirus y el edema en asociación con hemorragias. Estas lesiones se disponen, por lo general, siguiendo las arcadas vasculares temporales con invasión hacia la mácula. Se presentó una paciente de 24 años de edad, femenina, blanca, ama de casa, con antecedentes patológicos personales oculares sin datos de interés, y antecedentes patológicos personales generales de ser diagnosticadas con VIH. Hace cuatro años que comenzó con tratamiento antirretroviral, y tuvo cambios de tratamiento en dos ocasiones. El último fue impuesto en mayo del año 2011, con el cual presentó mala adherencia terapéutica, y comenzó desde entonces a presentar disminución de su peso corporal de forma marcada en breve período de tiempo. Refiere que desde hace unos meses comenzó a presentar una disminución progresiva de la agudeza visual en el ojo derecho, acompañado de visión borrosa. Adquiere gran importancia este caso, ya que ante la supervivencia de los pacientes con sida, va a ser cada vez más frecuente la aparición de las afecciones oculares relacionadas con esta enfermedad. Dentro de ellas se encuentran las infecciones oportunistas mayores como la retinitis por citomegalovirus.

Diferenciales salariales por género y región en Colombia: Una aproximación con regresión por cuantiles

Directory of Open Access Journals (Sweden)

Luis Armando Galvis

2010-12-01

Full Text Available La existencia de brechas salariales por género es un fenómeno que, al igual que en muchos otros países, está presente en el mercado laboral colombiano.Esas brechas no son homogéneas en todo el territorio, lo que justifica un análisis detallado de lo que ocurre en cada una de las regiones del país. Los resultados muestran diferenciales de salarios positivos en favor de los hombres en la mayoría de las ciudades principales. Sin embargo, no todo este fenómeno puede ser atribuido a la existencia de discriminación, por cuanto existen variados factores que explican parte de la brecha salarial. Para identificarlos se emplea la descomposición de Blinder-Oaxaca (BO en el contexto de regresión por cuantiles. Los resultadosde la aplicación de esta metodología sugieren que las brechas salariales no están explicadas por los atributos observables de los individuos. Dichas disparidades son en su mayoría explicadas por el efecto de las diferencias en la remuneración de atributos tales como la educación, además de elementos no observados. Por ciudades,el estudio muestra patrones que revelan una mayor brecha salarial en las regiones periféricas en comparación con Bogotá, Cali, Medellín, Manizales y Pereira.Dado que el efecto remuneración comprende, entre otros, la posible existencia de discriminación por género, es importante que se le otorgue la debida atención a este resultado para efectos de formular políticas en este sentido.

Mortalidad por meningitis por Pasteurella canis. Oportunidades de aprendizaje

Directory of Open Access Journals (Sweden)

Ana Rosa Ropero Vera

2016-01-01

Full Text Available La meningitis bacteriana es una enfermedad importante de distribución mundial, causa mayor y sustancial de mortalidad y morbilidad en países en desarrollo. La Organización Mundial de la Salud (OMS sostiene que la meningitis es una de las diez afecciones principales del ser humano y debe ser considerada como una emergencia infectológica; por eso es fundamental reconocer que esta enfermedad es causa de muerte en niños de todo el mundo, sin distinción de raza, nivel económico o sociocultural. Se realizó una investigación de caso en menor de 53 días de nacido, que cumplía con los criterios clínicos y de laboratorio compatible con meningitis bacteriana, con el propósito de analizar y fortalecer la toma de decisiones en salud pública por parte de la secretaría local de salud del municipio de Valledupar (Colombia. Entre los hallazgos se encontró antecedentes infecciosos en el menor, coloración de Gram y cultivo de LCR, en el que se identificó cocobacilos Gram negativos, que fueron aislados como agente causal Pasteurella canis. Este estudio pretende sensibilizar a los prestadores de salud para que cuenten con personal altamente capacitado para brindar tratamientos adecuados y prevenir complicaciones en la meningitis bacteriana en niños, y así disminuir la posibilidad de secuelas o muerte, tanto en pacientes con compromiso inmunológico o sin este.

Por un humor ético

Directory of Open Access Journals (Sweden)

Victor Paramo Valero

2016-04-01

Full Text Available Ética del humor es una obra original, abundantemente documentada, de contenido científico y filosófico, que aborda un problema de gran importancia en los actuales estudios de éticas aplicadas. La ética del humor es una nueva ética aplicada que pretende comprender el fenómeno del humor a la luz de sus implicaciones éticas. Como señala el autor, Juan Carlos Siurana, reputado experto en el ámbito de la filosofía práctica, el interés por el humor es un interés por la ética. En la obra no presenta una nueva teoría filosófica del humor –las cuales se han venido sucediendo, al menos, desde los Diálogos de Platón–, sino una nueva teoría ética, que toma al humor como objeto principal de análisis. Por tanto, la finalidad es realizar una aportación dentro del ámbito de la ética. Para ello se nutre de distintos estudios psicológicos, biológicos, fisiológicos y neurológicos sobre el humor, así como de clásicas obras de filosofía que han abordado esta cuestión.

Getting It Right the First Time: Defining Regionally Relevant Training Curricula and Provider Core Competencies for Point-of-Care Ultrasound Education on the African Continent.

Science.gov (United States)

Salmon, Margaret; Landes, Megan; Hunchak, Cheryl; Paluku, Justin; Malemo Kalisya, Luc; Salmon, Christian; Muller, Mundenga Mutendi; Wachira, Benjamin; Mangan, James; Chhaganlal, Kajal; Kalanzi, Joseph; Azazh, Aklilu; Berman, Sara; Zied, El-Sayed; Lamprecht, Hein

2017-02-01

Significant evidence identifies point-of-care ultrasound (PoCUS) as an important diagnostic and therapeutic tool in resource-limited settings. Despite this evidence, local health care providers on the African continent continue to have limited access to and use of ultrasound, even in potentially high-impact fields such as obstetrics and trauma. Dedicated postgraduate emergency medicine residency training programs now exist in 8 countries, yet no current consensus exists in regard to core PoCUS competencies. The current practice of transferring resource-rich PoCUS curricula and delivery methods to resource-limited health systems fails to acknowledge the unique challenges, needs, and disease burdens of recipient systems. As emergency medicine leaders from 8 African countries, we introduce a practical algorithmic approach, based on the local epidemiology and resource constraints, to curriculum development and implementation. We describe an organizational structure composed of nexus learning centers for PoCUS learners and champions on the continent to keep credentialing rigorous and standardized. Finally, we put forth 5 key strategic considerations: to link training programs to hospital systems, to prioritize longitudinal learning models, to share resources to promote health equity, to maximize access, and to develop a regional consensus on training standards and credentialing. Copyright © 2016 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

The Role of Hippocampal Estradiol Receptor-α in a Perimenopausal Affective Disorders-Like Rat Model and Attenuating of Anxiety by Electroacupuncture

Directory of Open Access Journals (Sweden)

Xun Wang

2016-01-01

Full Text Available Hormone replacement therapy is the principal treatment for perimenopausal affective disorders which can cause severe side effects. The present study compared the effects of electroacupuncture (EA and estradiol treatment on perimenopausal affective disorders at the behavioral and cellular levels. In this randomized experimental in vivo study, adult female rats were divided into intact, ovariectomy, chronic unpredictable stress (CUS, and ovariectomy and CUS combination groups. After week 6, all groups were subdivided to three subgroups of control, EA, and estradiol treatment. The behavioral parameters in the open field and the elevated plus maze tests were assessed before and after treatments. Alterations of serum steroid hormones and changes of estradiol receptor-α (ER-α immunofluorescence neurons in the hippocampus sections were evaluated. EA treatment caused more antianxiety effects than estradiol treatment in CUS group (P<0.05. Notably, estradiol and EA treatments had better significant behavioral effects when the models were not estrogen-deficient. Importantly, within each group, compared to the control group, the numbers of ER-α-positive neurons were significantly larger in EA subgroups. Therefore, EA had antianxiety effects on perimenopausal affective disorders caused by CUS but not by estrogen deficiency and upregulation of hippocampus ER-α neurons may contribute to its mechanism of action.

Escolhas Associadas ao Automóvel por Homens e por Mulheres: confluência ou divergência? Choices associated with automobiles for Men and Women: convergence or divergence? Opciones relacionadas con el Automóvil por Hombres y por Mujeres: ¿convergencia o divergencia?

Directory of Open Access Journals (Sweden)

LICHT, René Henrique Götz

2009-03-01

Full Text Available RESUMOO aumento do poder de compra das mulheres tem levado empresas a adotarem estratégias de diferenciação de produtos e a produzirem produtos específicos para o público feminino. A indústria automobilística não está imune a este fenômeno, uma vez que as mulheres representam aproximadamente metade das vendas de automóvel no país. Considerando as diferenças de consumo e de comportamento entre mulheres e homens é colocada a seguinte questão: há diferenças entre escolhas associadas ao automóvel por homens e mulheres? Foram apresentados aos participantes itens presentes no dia-a-dia das pessoas, e que são por elas valorizados; e foi solicitado aos participantes que escolhessem e associassem estes itens ao automóvel. A análise dos resultados revelou haver mais semelhanças do que diferenças entre escolhas associadas ao automóvel por homens e escolhas associadas ao automóvel por mulheres. A semelhança entre as escolhas sugere que as representações, os significados e valores atribuídos ao automóvel por homens e por mulheres são similares e, desta forma, a estratégia de diferenciação de produtos não se aplica à indústria automobilística.ABSTRACTThe increase of the women purchase power has led some companies to adopt strategies of products differentiation as well as to produce specific products to the female public. The auto industry is not immune to this phenomenon, once the women represent, approximately, half of the automobile sales in the country. Considering the consumption and the behavior differences between women and men, it has set the following question: are there differences between the choices associated to the automobile by men and the choices associated to the automobile by women? It has been presented to the participants items found in the people’s day-by-day, which are valorized by them, and the participants have been asked to choose and associate these items to the automobile. The results analysis

Acuerdo por la discreción

Directory of Open Access Journals (Sweden)

Yeny Serrano

2006-01-01

Full Text Available En este artículo se propone un análisis del texto del Acuerdo por la discreción firmado en 1999 por 32 directores de medios de comunicación para “elevar el nivel de calidad y responsabilidad en el cubrimiento y difusión de hechos violentos”. Se analizan los factores que impiden que este Acuerdo produzca cambios efectivos en la práctica profesional informativa y se presenta un modelo (Lemieux, 2000 que tiene en cuenta las variables que influyen en la producción del discurso informativo mediático.

Analysis of compliance and irregularity between Management Conservation and Director Plans: a case study of Birds Natural Park in the city of Rio das Ostras

Directory of Open Access Journals (Sweden)

Adiane Conceição de Oliveira

2010-05-01

Full Text Available In the presente work, the Director Plan of Rio das Ostras, Rio de Janeiro, Brazil, and the Management Plan of a municipal Conservation Unit (CU named Birds Natural Park were investigated aiming at detecting possible territorial management conflicts, as well as pointing out potential of using these two regulations as tools for improving life quality and for developing sustainable local strategies. The study allowed for the inference of the need to review not only the Director Plans of mediumsized cities, but also the Managements Plans of the Conservation Units (CUs. Furthermore, Director Plans must be consistent in terms of articles and objectives, detailing sustainable projects for CUs by means of action plans, chronograms for the implementation of ecological corridors, and use and occupation of CUs buffer zone criteria.

Enhanced reactive oxygen species through direct copper sulfide nanoparticle-doxorubicin complexation

Science.gov (United States)

Li, Yajuan; Cupo, Michela; Guo, Liangran; Scott, Julie; Chen, Yi-Tzai; Yan, Bingfang; Lu, Wei

2017-12-01

CuS-based nanostructures loading the chemotherapeutic agent doxorubicin (DOX) exerted excellent cancer photothermal chemotherapy under multi-external stimuli. The DOX loading was generally designed through electrostatic interaction or chemical linkers. However, the interaction between DOX molecules and CuS nanoparticles has not been investigated. In this work, we use PEGylated hollow copper sulfide nanoparticles (HCuSNPs) to directly load DOX through the DOX/Cu2+ chelation process. Distinctively, the synthesized PEG-HCuSNPs-DOX release the DOX/Cu2+ complexes into surrounding environment, which generate significant reactive oxygen species (ROS) in a controlled manner by near-infrared laser. The CuS nanoparticle-mediated photothermal ablation facilitates the ROS-induced cancer cell killing effect. Our current work reveals a DOX/Cu2+-mediated ROS-enhanced cell-killing effect in addition to conventional photothermal chemotherapy through the direct CuS nanoparticle-DOX complexation.

Clonación humana: las preguntas «por qué no» y «por qué sí»

Directory of Open Access Journals (Sweden)

Velayos Castelo, Carmen

2002-12-01

Full Text Available Why not cloning us is a relevant question for contemporary ethics. The question why not, when it refers to a technology (or to some of its applications, is the question for its moral limits. In other words, it is the question for the universal dangers that a technology entails or could entail in some of its applications. The sphere of the moral evaluation of a technology has to do with the public elimination of the possible harms that are inherent or supervenient to its utilisation. If we focus on the relevant normative questions of the justice sphere, it couldn´t be relevant to answer the question why, that is, why a person or a group of them would wish the technology was applied The question why is related to vital options and ways of create ourselves that needn´t be binding on someone nor are characteristic of the moral point of view. However, the suspicion of this article is the following: the specific character of contemporary technological innovation (of which cloning is a paradigmatic case stimulates and makes relevant the debate about the good (given the collective or global implications of the answers.

Por qué no clonarnos es una pregunta relevante para la ética actual. El por qué no de una técnica -o de determinadas aplicaciones de la misma- es la pregunta por los límites morales. O, de otro modo, es la pregunta por los daños objetivos que ésta supone, o supondría en una determinada aplicación. El marco de evaluación moral de una técnica tiene que ver, pues, con la desestimación pública y universal de posibles daños inherentes o sobrevenibles a su uso. Circunscritas las cuestiones normativas relevantes al ámbito de la justicia, no parecería relevante clarificar cuál sea el por qué -o el por qué sí- un individuo o un conjunto de ellos buscarían la aplicación o puesta en marcha de una técnica. Ésta es la pregunta por opciones vitales y

Orlando Castellanos. La pasión por la radio

OpenAIRE

Castellanos Molina, Orlando, 1930-1998

2004-01-01

Documento sonoro en el que se recogen entrevistas realizadas a Orlando Castellanos por Miguel Ángel de la Guardia, Miladys Ochoa, Fernando Rodríguez Sánchez (Ciego de Ávila), Ángel Ferrera, Boshmonar, Jaime Almiral, Radio Umbral de Santiago de Chile, Franco Carbón, Luis Toledo Sande y Estrella Díaz. Esta grabación pertenece a la colección Palabra Viva, desarrollada por el Centro Cultural Pablo de la Torriente Brau, a partir de las entrevistas realizadas por el periodista Orlando Castellanos. ...

The Global Redox Responding RegB/RegA Signal Transduction System Regulates the Genes Involved in Ferrous Iron and Inorganic Sulfur Compound Oxidation of the Acidophilic Acidithiobacillus ferrooxidans

Directory of Open Access Journals (Sweden)

Danielle Moinier

2017-07-01

Full Text Available The chemical attack of ore by ferric iron and/or sulfuric acid releases valuable metals. The products of these reactions are recycled by iron and sulfur oxidizing microorganisms. These acidophilic chemolithotrophic prokaryotes, among which Acidithiobacillus ferrooxidans, grow at the expense of the energy released from the oxidation of ferrous iron and/or inorganic sulfur compounds (ISCs. In At. ferrooxidans, it has been shown that the expression of the genes encoding the proteins involved in these respiratory pathways is dependent on the electron donor and that the genes involved in iron oxidation are expressed before those responsible for ISCs oxidation when both iron and sulfur are present. Since the redox potential increases during iron oxidation but remains stable during sulfur oxidation, we have put forward the hypothesis that the global redox responding two components system RegB/RegA is involved in this regulation. To understand the mechanism of this system and its role in the regulation of the aerobic respiratory pathways in At. ferrooxidans, the binding of different forms of RegA (DNA binding domain, wild-type, unphosphorylated and phosphorylated-like forms of RegA on the regulatory region of different genes/operons involved in ferrous iron and ISC oxidation has been analyzed. We have shown that the four RegA forms are able to bind specifically the upstream region of these genes. Interestingly, the phosphorylation of RegA did not change its affinity for its cognate DNA. The transcriptional start site of these genes/operons has been determined. In most cases, the RegA binding site(s was (were located upstream from the −35 (or −24 box suggesting that RegA does not interfere with the RNA polymerase binding. Based on the results presented in this report, the role of the RegB/RegA system in the regulation of the ferrous iron and ISC oxidation pathways in At. ferrooxidans is discussed.

The Global Redox Responding RegB/RegA Signal Transduction System Regulates the Genes Involved in Ferrous Iron and Inorganic Sulfur Compound Oxidation of the Acidophilic Acidithiobacillus ferrooxidans

Science.gov (United States)

Moinier, Danielle; Byrne, Deborah; Amouric, Agnès; Bonnefoy, Violaine

2017-01-01

The chemical attack of ore by ferric iron and/or sulfuric acid releases valuable metals. The products of these reactions are recycled by iron and sulfur oxidizing microorganisms. These acidophilic chemolithotrophic prokaryotes, among which Acidithiobacillus ferrooxidans, grow at the expense of the energy released from the oxidation of ferrous iron and/or inorganic sulfur compounds (ISCs). In At. ferrooxidans, it has been shown that the expression of the genes encoding the proteins involved in these respiratory pathways is dependent on the electron donor and that the genes involved in iron oxidation are expressed before those responsible for ISCs oxidation when both iron and sulfur are present. Since the redox potential increases during iron oxidation but remains stable during sulfur oxidation, we have put forward the hypothesis that the global redox responding two components system RegB/RegA is involved in this regulation. To understand the mechanism of this system and its role in the regulation of the aerobic respiratory pathways in At. ferrooxidans, the binding of different forms of RegA (DNA binding domain, wild-type, unphosphorylated and phosphorylated-like forms of RegA) on the regulatory region of different genes/operons involved in ferrous iron and ISC oxidation has been analyzed. We have shown that the four RegA forms are able to bind specifically the upstream region of these genes. Interestingly, the phosphorylation of RegA did not change its affinity for its cognate DNA. The transcriptional start site of these genes/operons has been determined. In most cases, the RegA binding site(s) was (were) located upstream from the −35 (or −24) box suggesting that RegA does not interfere with the RNA polymerase binding. Based on the results presented in this report, the role of the RegB/RegA system in the regulation of the ferrous iron and ISC oxidation pathways in At. ferrooxidans is discussed. PMID:28747899

Afetividade entre professor e aluno no processo ensino-aprendizagem

Directory of Open Access Journals (Sweden)

Jéssica Simone Galdino Schaefer

2015-06-01

Full Text Available Este artigo tem como objetivo analisar as relações de afetividade entre professor e aluno no processo ensino-aprendizagem. Utiliza de metodologia com abordagem qualitativa, observação participante, e entrevistas semi-estruturadas. O lócus da pesquisa foi a Escola Municipal de Educação Básica Lizamara Aparecida Oliva de Almeida em Sinop, entre Fevereiro e Maio de 2014. Enquanto sujeitos, contou-se com professores e alunos do 3º ano do Ensino Fundamental. Dos resultados parciais, verificou-se que mesmo que a afetividade e a aprendizagem sejam reconhecidas teoricamente por Henri Wallon como elos fundamentais para o processo ensino-aprendizagem, ainda não é bem compreendido pelos sujeitos professores. Palavras-chave: psicologia educacional; afetividade; professores e alunos. 

MIASIS CUTÁNEA POR CORDYLOBIA ANTHROPOPHAGA

Directory of Open Access Journals (Sweden)

Miriam Alkorta Gurrutxaga

2001-01-01

Full Text Available El incremento progresivo en el número de personas que viajan a países tropicales ha hecho que las enfermedades importadas adquieran una relevancia cada vez mayor. Las miasis (o infestaciones por larvas de moscas cutáneas se encuentran entre este tipo de enfermedades siendo especialmente frecuentes en países tropicales. A propósito de la observación de un caso de miasis cutánea masiva por Cordylobia antropophaga, que ocurrió en una mujer de 34 años de edad al volver de un viaje a Senegal, se ha efectuado una revisión de los casos de miasis cutáneas forunculoides importadas publicados en España, así como de la biología, patología, tratamiento y prevención de la miasis humana por Cordylobia anthropophaga. El caso referido, se caracterizó por la infestación con un número inusualmente elevado de larvas, no sospechándose su etiología hasta la fase final de la enfermedad. La emergencia continuada de larvas (se recogieron 91 generó en la paciente un estado de ansiedad importante. Finalmente, la eliminación de las larvas provocó una rápida mejoría de la paciente. Aunque los casos de miasis cutánea no tienen la gravedad de otras enfermedades importadas, su conocimiento es necesario desde el punto de vista preventivo, diagnóstico y terapeútico. Es importante proceder a la identificación morfológica de las larvas diferenciándolas de otro tipo de miasis con implicaciones terapéuticas diferentes.

Mortalidade por leucemias relacionada à industrialização

Directory of Open Access Journals (Sweden)

Leal Carmen Helena Seoane

2002-01-01

Full Text Available OBJETIVO: Analisar a distribuição espacial da mortalidade por leucemia na população, buscando identificar agregados e estabelecer sua relação com os níveis de industrialização. MÉTODOS: O estudo foi realizado nas 43 regiões de governo do Estado de São Paulo, no qüinqüênio 1991-1995. Foi construído um "índice de industrialização relativo à leucemia" (IIRL baseado no número de indústrias e empregos industriais por 100.000 habitantes, valor adicionado fiscal, variedade de ramos industriais e indústrias com potenciais exposições de risco para a leucemia. O IIRL foi distribuído em cinco categorias. Verificaram-se os coeficientes padronizados de mortalidade por leucemia em cada uma das regiões, também distribuídos em cinco categorias e comparados ao mapa IIRL. RESULTADOS: As regiões mais industrializadas em ordem decrescente foram Campinas, Piracicaba, Jundiaí, Sorocaba e São Paulo. Não foi encontrada associação entre mortalidade, por nenhum tipo de leucemia, e industrialização. A região de Jales foi a que apresentou o mais alto coeficiente padronizado de mortalidade por leucemia. CONCLUSÕES: A distribuição da mortalidade por leucemia ocorreu de forma homogênea no Estado de São Paulo, não apresentando correlação com o nível de industrialização. Entretanto, aspectos relacionados ao método epidemiológico adotado -- estudo ecológico -- e ao uso do parâmetro "mortalidade por leucemia", doença cujo prognóstico tem mudado muito nas últimas décadas, limitaram a interpretação dos resultados.

Perspectivas mecanisticas de reações organicas catalisadas por paladio : Heck, oxa-Heck e acoplamento de Buchwald-Hartwig por ESI-MS/MS

OpenAIRE

Boniek Gontijo Vaz

2009-01-01

Resumo: A espectrometria de Massas por eletronspray (ESI-MS) tornou-se um método prático para o estudo de mecanismos reacionais em solução. Neste trabalho importantes reações catalisadas por paládio: reação de Heck-Mizoroki, oxa-Heck e o acoplamento de Buchwald-Hartwig foram monitoradas por ESI-MS visando interceptar espécies que comprovam as atuais propostas mecanísticas ou que abram caminho para novas propostas para estas reações. O monitoramento das reações foi realizado no modo off-line, ...

DE ACUMULACIÓN POR DESPOSESIÓN

Directory of Open Access Journals (Sweden)

Sebastián Gómez Lende

2015-01-01

Full Text Available Omnipresente, la acumulación por desposesión es uno de los elementos centrales del orden global contemporáneo. Observados desde una perspectiva crítica, los usos extractivos del territorio constituyen una de las principales expresiones de ese proceso. A la luz de ese sistema de ideas, este artículo procura demostrar que el modelo sojero actualmente vigente en la Argentina es una de las formas más completas, exhaustivas, actuales y sofisticadas, de acumulación por desposesión en el país. En ese sentido, el artículo analiza el boom de la soja transgénica y sus vínculos con las formas tanto seculares (endeudamiento financiero, concentración de la propiedad rural, usurpación de la tierra y actuales de desposesión (degradación de la naturaleza, despojo del derecho a la salud, pillaje de recursos genéticos efectuadas por los grandes agricultores, el capital financiero, las agroindustrias y las corporaciones biotecnológicas, en detrimento de los pequeños productores, los campesinos, los pueblos aborígenes y la población en general.

La compra por impulso de productos de alimentación

DEFF Research Database (Denmark)

Luna-Arocas, Roberto; Bech-Larsen, Tino

2004-01-01

El consumo de productos de alimentación muestra una serie de matices diferenciales en su análisis si lo comparamos con otros productos de compra por impulso. En este sentido, se relaciona la compra por impulso de productos de alimentación con una baja importancia de la imagen fisica, y con las de...... descrepancias personales entre lo que un individuo es y quiere ser. Como resultado en una mestra de estudisantes, la compra por impulso de productes de alimentación se relaciona con imagen fisica pero no con las discrepanacias personales.......El consumo de productos de alimentación muestra una serie de matices diferenciales en su análisis si lo comparamos con otros productos de compra por impulso. En este sentido, se relaciona la compra por impulso de productos de alimentación con una baja importancia de la imagen fisica, y con las...

Itinerarios didácticos por la isla de Tenerife

OpenAIRE

Becerra Ramírez, María Carmen; Javier Dóniz-Páez; González Cárdenas, Elena; Gosálvez, Rafael U.; Becerra-Ramírez, Rafael; Escobar Lahoz, Estela

2013-01-01

Con la elaboración de esta guía de Itinerarios Didácticos por la isla de Tenerife pretendemos contribuir a un mayor conocimiento de las características geográficas de un espacio dominado por las formas y formaciones volcánicas que caracterizan un paisaje fuertemente modificado por la actividad humana. El hombre convive y usa lo que los volcanes le ofrecen, tradicionalmente como soporte de sus cultivos o de su actividad ganadera,y modernamente como base de la industria turística. Los itiner...

¿Por qué estudiar en la Universidad EAN?

OpenAIRE

2013-01-01

Razones para estudiar en la Universidad EAN: 1. Por ser la Universidad No.1 en Latinoamérica y No. 28 en el mundo, según el ranking mundial de Escuelas de Negocios que lidera el Consejo Superior de Investigaciones Científicas – Laboratorio de Cibermetría de España. 2. Por la flexibilidad en los planes de estudio que permite adelantar unidades y cursar la carrera en un tiempo menor. 3. Por la formación académica en dos ciclos semestrales, favoreciendo el aprendizaje y la concentrac...

"Efecto del ingreso obtenido por el socio industrial por concepto de alimentos en la sociedad en nombre colectivo"

OpenAIRE

Adame Alba, Nayzeth

2011-01-01

Hoy en día la excesiva carga tributaria en nuestro país, nos obliga a buscar alternativas factibles y seguras, en el cumplimiento de las obligaciones fiscales, por ello, debemos aprovechar la existencia de figuras jurídicas útiles para la optimización de recursos financieros dentro del marco de ley, es el caso de la sociedad en nombre colectivo, que nos permite la existencia de socios industriales que a su vez, el ingreso que perciben por concepto de alimentos se encuentra exento de impuestos...

ANTIOXIDANTES: MICRONUTRIENTES EN LUCHA POR LA SALUD

OpenAIRE

Zamora S, Juan Diego

2007-01-01

Los antioxidantes son sustancias químicas que se caracterizan por impedir o retrasar la oxidación de diversas sustancias principalmente de los ácidos grasos cuyas reacciones se producen tanto en los alimentos como en el organismo humano, en el cual puede provocar alteraciones fisiológicas importantes desencadenantes de diversas enfermedades. Otra de las funciones de los antioxidantes es facilitar el uso fisiológico del oxígeno por parte de las mitocondrias celulares, ayudando a reducir los ef...

Esporotricosis diagnosticada por el laboratorio

Directory of Open Access Journals (Sweden)

Nelly Ordóñez

1989-06-01

Full Text Available De 1976 a 1989 se han diagnosticado 40 casos de esporotricosis en el laboratorio de Micología del Instituto Nacional de Salud. La enfermedad se presentó en pacientes entre 4 y 52 años y tuvo predilección por el sexo masculino: 35 de 40 (87,5%; las formas clínicas más frecuentes fueron la cutánea fija, 18 de 40 (45%, y la linfocutánea, 17 de 40 (42,5%, con localización mayor en miembros superiores, 18 de 40 (45%. El diagnóstico se estableció por el aislamiento del Sporothrix schenckii en 35 de 38 pacientes (92%; los otros dos pacientes se diagnosticaron empleando otras técnicas: inmunofluorescencia directa, intradermorreacción y aglutinación en tubo.

Análise Sazonal das Regiões do Rio Grande do Sul Atingidas por Eventos Severos Gerados por SCM no Período de 2004 a 2008

Directory of Open Access Journals (Sweden)

Gustavo Rasera

2012-07-01

Full Text Available ntos Severos (ES, como por exemplo, vendaval, granizo e enchente, têm sido estudados com frequência devido à gravidade dos danos que estes causam à sociedade. Um dos sistemas meteorológicos que é bastante comum no Rio Grande do Sul (RS, e que frequentemente está associado aos ES são os Sistemas Convectivos de Mesoescala (SCM. Como a economia do RS é voltada majoritariamente para a agricultura, que é bastante suscetível às mudanças do tempo, é frequente no Estado a ocorrência de prejuízos econômicos causados por ES. Diante disso, o objetivo deste trabalho foi analisar a distribuição sazonal das regiões atingidas por ES gerados por SCM que afetaram o RS (ESSCMRS no período de 2004 a 2008. Foram utilizados, para o período de estudo, dados de ocorrências de ES e municípios atingidos por ES (MAES obtidos no banco de dados da Coordenadoria Estadual de Defesa Civil do RS; trajetórias dos SCM que afetaram o RS (SCMRS geradas a partir de informações fornecidas pela ferramenta ForTrACC (Forecasting and Tracking of Active Cloud Clusters e imagens brutas do satélite GOES 10 e 12 do canal 4. Os resultados obtidos mostraram que: i ~45% dos ES observados foram gerados por SCMRS; ii ~58% dos MAES foram atingidos por SCMRS; iii a porção norte do RS foi a mais atingida por ESSCMRS; iv vendaval e granizo foram os tipos de ESSCMRS que atingiram o maior número de municípios e v JAS (jul-ago-set foi o trimestre que apresentou o maior número de municípios atingidos por ESSCMRS (MAES-SCMRS.

El aprendizaje visto por los estudiantes venezolanos

Directory of Open Access Journals (Sweden)

Berta Elena Barrios

2015-01-01

Full Text Available En el siguiente trabajo se presentan los resultados de un estudio sobre las con-cepciones del aprendizaje de un grupo de estudiantes venezolanos de educa-ción primaria y media. Se trató de replicar el instrumento y procedimiento deanálisis utilizado por los investigadores Berry y Sahlberg (1996, con el objetivode caracterizar cómo conciben el aprendizaje estudiantes venezolanos entre 11y 15 años de edad y compararlo con sus pares ingleses y finlandeses. El análi-sis de resultados se basó en los criterios propuestos por dichos autores, deno-minados Pasos para un Buen Aprendizaje. Los hallazgos indican que los estu-diantes venezolanos conciben el aprendizaje como memorizar conocimientos,básicamente escolares, enseñados por los docentes. Las concepciones deambas poblaciones se ubican en una visión pasiva del aprendizaje. Se discutela vinculación de las concepciones del aprendizaje con las prácticas de la escuela.

Epidemiologia das infecções hematogênicas por Candida spp

Directory of Open Access Journals (Sweden)

Colombo Arnaldo Lopes

2003-01-01

Full Text Available O gênero Candida spp é responsável por cerca de 80% das infecções fúngicas no ambiente hospitalar e constitui causa relevante de infecções de corrente sanguínea. Nos Estados Unidos da América, Candida spp é a quarta causa mais comum de infecções de corrente sanguínea, respondendo por cerca de 8% dos casos das infecções documentadas neste sítio. Espécies não-albicans respondem hoje por ao menos 50% das infecções invasivas por Candida spp, apresentando peculiaridades de história natural e sensibilidade a antifúngicos. A mortalidade geral de fungemias por Candida spp é da ordem de 40 a 60%, tornado esta complicação infecciosa um grande desafio para os clínicos que trabalham em hospitais terciários em diferentes países.

Neumonitis por hipersensibilidad en la ciudad de México

Directory of Open Access Journals (Sweden)

Carrillo-Rodríguez José G.

2000-01-01

Full Text Available OBJETIVO: Determinar la asociación entre la zona urbana de origen del paciente en la ciudad de México y la prevalencia de neumonitis por hipersensibilidad inducida por antígeno aviario. MATERIAL Y MÉTODOS: Se trata de un estudio de casos y controles realizado en el Instituto Nacional de Enfermedades Respiratorias, en la ciudad de México, en el año de 1999. Se estudiaron 109 casos con neumonitis por hipersensibilidad y 184 controles: de éstos, 39, con fibrosis pulmonar idiopática; 63, con tuberculosis pulmonar, y 82, con asma. La ciudad de México y las zonas conurbadas se dividieron en cinco zonas geográficas: centro, noreste, sureste, noroeste y el suroeste. Se calcularon las prevalencias de las diferentes enfermedades por zona urbana de los pacientes que participaron en el estudio; como medida de asociación, se estimó la razón de momios, con un intervalo de confianza al 95%. Asimismo, se realizó regresión logística múltiple ajustando por edad, sexo y estrato socioeconómico. RESULTADOS: Ochenta casos de neumonitis por hipersensibilidad se concentraron en el sur del noreste de las zonas conurbadas y la parte norte del sureste de la ciudad de México, 48 y 32, respectivamente (RM= 3.86, IC 95% 2.17-6.96. Treinta y seis controles de asma se localizaron en el suroeste de la ciudad de México, zona donde se ubica el Intituto Nacional de Enfermedades Respiratorias (p<0.05 y cuatro en la zona conurbada. Los controles de tuberculosis pulmonar y fibrosis pulmonar idiopática estuvieron dispersos en la ciudad de México y en las zonas conurbadas. CONCLUSIONES: La zona sur del noreste y el norte de la sureste están asociadas a la neumonitis por hipersensibilidad. Las causas de esta asociación no parece ser geográfica, pero existe el antecedente de que esa zona fue basurero de la ciudad, por lo que partículas orgánicas en el ambiente pudieran coadyuvar a la aparición de esta enfermedad.

The Effect of Specific Conditions on Cu, Ni, Zn and Al Recovery from PCBS Waste Using Acidophilic Bacterial Strains

Directory of Open Access Journals (Sweden)

Mrážiková A.

2016-03-01

Full Text Available The objective of this work was to evaluate the influence of static, stirring and shaking conditions on copper, zinc, nickel and aluminium dissolution from printed circuit boards (PCBs using the mixed acidophilic bacterial culture of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans. The results revealed that static conditions were the most effective in zinc and aluminium dissolution. Zinc was removed almost completely under static conditions, whereas maximum of nickel dissolution was reached under the stirring conditions. The highest copper recovery (36% was reached under stirring conditions. The shaking conditions appeared to be the least suitable. The relative importance of these systems for the bioleaching of copper and nickel decreased in the order: stirring, static conditions, shaking.

PANORAMA LATINOAMERICANO DEL PAGO POR SERVICIOS AMBIENTALES

Directory of Open Access Journals (Sweden)

González T. Ángela

2008-07-01

Full Text Available Este documento busca proveer al lector de algunos elementos para el análisis y reflexión en torno al pago por servicios ambientales. Para ello, en primera instancia, aborda algunos conceptos básicos relacionados con economía ambiental, seguido de temas como la valoración económica de servicios ambientales y la implementación de mecanismos de pago por algunos de ellos. Lo anterior esta enriquecido con experiencias o estudios de caso a nivel latinoamericano y colombiano.

Efeito protetor da melatonina sobre intoxicações por herbicidas

Directory of Open Access Journals (Sweden)

Lécio L. de Almeida

2016-03-01

Full Text Available Resumo: O uso inadequado de herbicidas pode resultar em intoxicações agudas e, às vezes, crônicas por exposição em longo prazo a baixos níveis desses agentes tóxicos, podendo o herbicida atuar também como agentes teratogênicos, mutagênicos, cancerígenos e desreguladores endócrinos, com o aparecimento de doenças neurodegenerativas e distúrbios reprodutivos. Estudos têm revelado que a melatonina tem propriedades antioxidantes, anti-inflamatórias e imunomoduladoras e atua na reprodução. Essa indolamina está entre os agentes que têm se mostrado benéfico em intoxicações por herbicidas, porém não há relatos do uso de melatonina contra intoxicações por Glifosato-Roundup®, muito menos em associação com o Paraquat. Dessa forma, o maior interesse no tratamento das intoxicações por herbicidas, tem-se concentrado em medidas que impeçam ou minimizem as lesões celulares provocadas nos diversos sistemas biológicos. Assim, a melatonina, como antioxidante conhecido, pode ser mais uma alternativa contra as intoxicações por herbicidas associados e/ou individuais.

Eficacia del Albendazol en dosis única sobre las infecciones por helmintos transmitidos por el suelo en escolares de una comunidad de Iquitos, Perú

Directory of Open Access Journals (Sweden)

Theresa W Gyorkos

Full Text Available Objetivos. Determinar la eficacia en dosis única del albendazol sobre las infecciones por helmintos transmitidos por el suelo (HTS en escolares de una comunidad de la ciudad de Iquitos en Perú. Materiales y métodos. Dentro del contexto de un ensayo controlado aleatorizado realizado en una comunidad periurbana de escasos recursos, situada en Iquitos, en la Amazonía de Perú, se obtuvieron muestras de heces de escolares del quinto grado de primaria en 18 escuelas y se analizó la prevalencia y la intensidad de HTS. Un total de 1193 escolares fueron desparasitados con albendazol en dosis única (400 mg. De los 909 escolares que fueron encontrados positivos con al menos una infección por HTS, una muestra aleatoria de 385 fue seguida dos semanas más tarde, cuando se recolectó y analizó una segunda muestra de heces. Resultados. La eficacia del albendazol fue satisfactoria para las infecciones por Ascaris lumbricoides con una tasa de reducción de huevos (TRH de 99,8%; IC 95: 99,3-100 y por anquilostomideos con una TRH de 93,6%, IC 95%: 88,2-96,6 y por Trichuris trichiura con una TRH de 72,7%, IC 95: 58,5-79,1. Conclusiones. Estos resultados son indicativos de niveles satisfactorios de eficacia y son congruentes con datos publicados sobre la eficacia del albendazol y directivas de la Organización Mundial de la Salud. Futuras investigaciones deben centrarse en mejorar la eficacia de las estrategias de tratamiento para la infección por Trichuris trichiura.

Caffeine acts through neuronal adenosine A2A receptors to prevent mood and memory dysfunction triggered by chronic stress.

Science.gov (United States)

Kaster, Manuella P; Machado, Nuno J; Silva, Henrique B; Nunes, Ana; Ardais, Ana Paula; Santana, Magda; Baqi, Younis; Müller, Christa E; Rodrigues, Ana Lúcia S; Porciúncula, Lisiane O; Chen, Jiang Fan; Tomé, Ângelo R; Agostinho, Paula; Canas, Paula M; Cunha, Rodrigo A

2015-06-23

The consumption of caffeine (an adenosine receptor antagonist) correlates inversely with depression and memory deterioration, and adenosine A2A receptor (A2AR) antagonists emerge as candidate therapeutic targets because they control aberrant synaptic plasticity and afford neuroprotection. Therefore we tested the ability of A2AR to control the behavioral, electrophysiological, and neurochemical modifications caused by chronic unpredictable stress (CUS), which alters hippocampal circuits, dampens mood and memory performance, and enhances susceptibility to depression. CUS for 3 wk in adult mice induced anxiogenic and helpless-like behavior and decreased memory performance. These behavioral changes were accompanied by synaptic alterations, typified by a decrease in synaptic plasticity and a reduced density of synaptic proteins (synaptosomal-associated protein 25, syntaxin, and vesicular glutamate transporter type 1), together with an increased density of A2AR in glutamatergic terminals in the hippocampus. Except for anxiety, for which results were mixed, CUS-induced behavioral and synaptic alterations were prevented by (i) caffeine (1 g/L in the drinking water, starting 3 wk before and continued throughout CUS); (ii) the selective A2AR antagonist KW6002 (3 mg/kg, p.o.); (iii) global A2AR deletion; and (iv) selective A2AR deletion in forebrain neurons. Notably, A2AR blockade was not only prophylactic but also therapeutically efficacious, because a 3-wk treatment with the A2AR antagonist SCH58261 (0.1 mg/kg, i.p.) reversed the mood and synaptic dysfunction caused by CUS. These results herald a key role for synaptic A2AR in the control of chronic stress-induced modifications and suggest A2AR as candidate targets to alleviate the consequences of chronic stress on brain function.

ENSAYOS DE CREEP POR TORSIÓN Y TRACCIÓN

OpenAIRE

Daniela Alessio; Sandra Robles; Lilian Moro; René Molina

2017-01-01

En este estudio se efectúa el análisis de dos metodologías de ensayo para evaluar el comportamiento de un material al creep o fluencia por activación térmica o termofluencia. Se realizaron en laboratorio dos tipos de ensayos, por torsión y por tracción, bajo combinaciones de temperatura y tensión comparables, de un acero austenítico, de uso habitual en los equipos de la industria petroquímica de la región. Con los registros adquiridos, se graficaron las diferentes curvas deformación-tiempo de...

Premian record transmision de datos a 5,44 gigabits por segundo

CERN Multimedia

2003-01-01

"El Laboratorio Europeo para la Fisica de Particulas (CERN) y el Instituto de Tecnologia de California (EEUU) seran galardonados con un premio por haber conseguido batir el record de velocidad de transmision por Internet a 5,44 gigabits por segundo, informaron hoy, miercoles, fuentes de ambos organismos" (1/2 page).

Multiple mechanisms of phase variation of PorA in Neisseria meningitidis

NARCIS (Netherlands)

van der Ende, A.; Hopman, C. T.; Dankert, J.

2000-01-01

Previously, we reported that PorA expression in Neisseria meningitidis is modulated by variation in the length of the homopolymeric tract of guanidine residues between the -35 and -10 regions of the promoter or by deletion of porA. To reveal additional mechanisms of variation in PorA expression, the

Celulitis por Microascus trigonosporus(anamorfo Scopulariopsis trigonospora

Directory of Open Access Journals (Sweden)

DELIA CANLE CORTIÑAS

2013-06-01

Full Text Available Resumen: Microascus trigonosporus ( anamorfo Scopulariopsis trigonospora es un hongo filamentoso ubicuo que se encuentra en el suelo , plumas de aves, material vegetal e insectos. Aunque Scopulariopsis spp se consideran comúnmente hongos contaminantes , pueden causar ocasionalmente infecciones en humanos, en especial onicomicosis . Excepcionalmente se han descrito infecciones de piel, abscesos cerebrales, endocarditis ,sinusitis e infecciones diseminadas por Scopulariopsis spp , casi siempre en pacientes inmunodeprimidos . En los últimos años se han publicado un mayor número de casos de infecciones oportunistas por Scopulariopsis spp y otros hialohifomicetos multiresistentes. Todavía no está establecido cuál es el mejor régimen de tratamiento para las infecciones por Scopulariopsis spp. Presentamos un caso excepcional de celulitis por Microascus trigonosporus en un paciente con tratamiento prolongado con corticoides. Abstract: Microascus trigonosporus ( Anamorph Scopulariopsis trigonospora is a cosmopolitan filamentous fungus that inhabits soil, feathers ,plant material and insects. While Scopulariopsis is commonly considered as a contaminat fungus it may cause occasionally infections in humans ,especially onychomycosis .Skin lesions, brain abscess , endocarditis, sinusitis and disseminated infections due to Scopulariopsis species have been rarely reported , usually in immunocompromised patients . Over the last few years opportunistic infections by Scopulariopsis species and others multi-resistant hyalohyphomycetes have been increasingly reported . No clear treatment regimen for Scopulariopsis species infections has been established yet. We present a exceptional case of cellulitis due to Microascus trigonosporus in a patient with prolonged steroid therapy.

System design description for portable 1,000 CFM exhauster Skids POR-007/Skid E and POR-008/Skid F

International Nuclear Information System (INIS)

Nelson, O.D.

1998-01-01

The primary purpose of the two 1,000 CFM Exhauster Skids, POR-007-SKID E and POR-008-SKID F, is to provide backup to the waste tank primary ventilation systems for tanks 241-C-106 and 241-AY-102, and the AY-102 annulus in the event of a failure during the sluicing of tank 241-C-106 and subsequent transfer of sluiced waste to 241-AY-102. This redundancy is required since both of the tank ventilation systems have been declared as Safety Class systems

Variabilidad estacional de hospitalizaciones por varicela en el INSN, Lima-Perú

Directory of Open Access Journals (Sweden)

Edwin Miranda-Choque

2013-04-01

Full Text Available Objetivo: Determinar las variabilidad estacional de hospitalizaciones por varicela. Diseño: Serie de casos. Institución: Instituto Nacional de Salud del Niño (INSN del Perú. Participantes: Niños hospitalizados por varicela. Intervenciones: Se estudió las hospitalizaciones por varicela de niños atendidos en el INSN del Perú desde el año 2001 hasta el 2011, país sin implementación de la vacunación contra la varicela; se identificó a los pacientes de la oficina de estadística. Principales medidas de resultados: Variabilidad estacional de hospitalizaciones de los niños atendidos por varicela. Resultados: Se estudió a 1 566 niños hospitalizados por varicela, siendo la mediana de edad de 2 años 6 meses, 46,4% (727/1 466 de sexo femenino, mediana de estancia hospitalaria seis días (RIQ:9,4. El grupo etario más afectado fue de 0 a 2 años, correspondiendo al 55% (864/1 566. En la curva de frecuencias de hospitalizaciones por varicela por meses evidenciamos la distribución estacional, con una tendencia al incremento cada vez mayor por año. Las hospitalizaciones por varicelas con al menos alguna complicación correspondieron a 68,5%(1 073/1 566. El porcentaje de fallecidos fue 0,83% (13/1 493. Conclusiones: Las hospitalizaciones por varicela en el INSN es una causa importante de morbilidad, con una tendencia estacional, siendo más frecuente en los meses de noviembre a febrero, con el incremento cada vez mayor por año y supone una importante carga económica.

Mortalidad por paludismo en Colombia, 1979-2008

OpenAIRE

Pablo Chaparro; Julio Padilla

2012-01-01

Introducción. En Colombia, el paludismo representa un grave problema de salud pública. Se estima que, aproximadamente, 60 % de la población se encuentra en riesgo de enfermar o de morir por esta causa. Objetivo. Describir la tendencia de la mortalidad por paludismo en Colombia desde 1979 hasta 2008. Materiales y métodos. Se llevó a cabo un estudio descriptivo para determinar la tendencia de las tasas de mortalidad. Las fuentes de información fueron las bases de datos de las defunciones...

Running exercise protects the capillaries in white matter in a rat model of depression.

Science.gov (United States)

Chen, Lin-Mu; Zhang, Ai-Pin; Wang, Fei-Fei; Tan, Chuan-Xue; Gao, Yuan; Huang, Chun-Xia; Zhang, Yi; Jiang, Lin; Zhou, Chun-Ni; Chao, Feng-Lei; Zhang, Lei; Tang, Yong

2016-12-01

Running has been shown to improve depressive symptoms when used as an adjunct to medication. However, the mechanisms underlying the antidepressant effects of running are not fully understood. Changes of capillaries in white matter have been discovered in clinical patients and depression model rats. Considering the important part of white matter in depression, running may cause capillary structural changes in white matter. Chronic unpredictable stress (CUS) rats were provided with a 4-week running exercise (from the fifth week to the eighth week) for 20 minutes each day for 5 consecutive days each week. Anhedonia was measured by a behavior test. Furthermore, capillary changes were investigated in the control group, the CUS/Standard group, and the CUS/Running group using stereological methods. The 4-week running increased sucrose consumption significantly in the CUS/Running group and had significant effects on the total volume, total length, and total surface area of the capillaries in the white matter of depression rats. These results demonstrated that exercise-induced protection of the capillaries in white matter might be one of the structural bases for the exercise-induced treatment of depression. It might provide important parameters for further study of the vascular mechanisms of depression and a new research direction for the development of clinical antidepressant means. J. Comp. Neurol. 524:3577-3586, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

El estrés por temperatura provoca necrosis en tabaco negro; cuantificación por análisis de imágenes

Directory of Open Access Journals (Sweden)

Eduardo Ortega

2008-07-01

de imágenes ImageJ. Este programa es capaz de adquirir, mostrar, editar, resaltar y analizar imágenes. Se demostró que las hojas sometidas a 4 ºC, independientemente del tiempo de exposición, presentaron una mayor área necrosada (35% en comparación con el resto de los tratamientos. Las áreas con acumulación de H2O2 in situ fueron mayores en los tratamientos de estrés por temperaturas altas (45 y 60 oC. La detección y cuantificación de la necrosis producida por temperaturas extremas, combinando el método del azul de tripano con el análisis de imágenes, es una herramienta útil para valorar los daños producidos por estrés de temperaturas y pudiera ser utilizado para valorar los daños celulares provocados por otros tipos de estrés.Palabras clave: variedad-Habana-2000; especies reactivas de oxígeno; H2O2;; Habana-2000-variety; reactive oxygen species.

ESTUDIO DEL IMPACTO TÉCNICO DE MEZCLAS DE CONCRETO HIDRÁULICO POR LA SUSTITUCIÓN PARCIAL DE CEMENTO POR ZEOLITA

Directory of Open Access Journals (Sweden)

I. Miranda Pasos

2014-06-01

Full Text Available La industria de la construcción cada vez más consciente de la necesidad de ejecutar obras con materiales que se obtengan y/o utilicen procesos industriales que minimicen la contaminación y, que contribuyan en el comportamiento de un producto como lo es el concreto hidráulico en la construcción, ha estado buscando alternativas de materiales que sustituyan total o parcialmente al cemento por otro cementante que contamine menos en su procesos de obtención y que conserve las propiedades o las mejore. Una alternativa para sustitución parcial del cemento es la zeolita, es un mineral que se obtiene por proceso de excavación y molienda de puzolana. La norma ASTM-618, define a las puzolanas como materiales silíceo o aluminio-silíceo que por sí solo poseen poco a ningún valor cementante, pero cuando se han dividido finamente y en presencia de agua e hidróxido de calcio (Cal reaccionan químicamente a temperatura ambiente para formar cementantes (Miranda, 2008. Recientemente se ha estudiado el efecto de adicionar mineral Cal-Zeolita para la elaboración del concreto, cuyos resultados son favorables al comportamiento mecánico y su durabilidad (Dopico J.J., et al. 2009. Para la elaboración de morteros para recubrimientos al incorporar arenas zeolíticas como sustituto de la arena tradicional (Tiburcio et al. 2008. El presente proyecto evaluó el comportamiento del concreto hidráulico en estado fresco y endurecido al sustituir de manera parcial cemento por zeolita. Se enfocó a la evaluación del comportamiento mecánico como al diseño de la mezcla de concreto hidráulico fabricado con cemento normal y con cemento-zeolita. Tomando en cuenta los resultados obtenidos, la zeolita incorporada en porcentajes entre el 5% y 10 % tiende a valores de resistencias muy cercanos al concreto normal, los modelos obtenidos así lo corroboran, por lo que se puede concluir la factibilidad de sustitución parcial de cemento por zeolita tomando en cuenta el

PERFIL DOS ATENDIMENTOS POR CAUSAS EXTERNAS EM HOSPITAL PÚBLICO

Directory of Open Access Journals (Sweden)

Marlos Victor Fonsêca de Lima

2012-01-01

Full Text Available El objetivo fue identificar el perfil de los atendimientos por causas externas en la urgencia de un hospital público de referencia del Estado. Investigación descriptiva documental, con enfoque cuantitativo. En el análisis de datos, el período de enero a diciembre de 2009 se realizó 4.464 atendimientos por causas externas. La mayor frecuencia de las lesiones ocurrió en personas entre 21 y 40 años (37,70% y hombres (68,6%. Cuanto a las causas, las caídas (29% fue la mayor variable, seguido por accidente de motocicleta (17,98%, accidentes domiciliario (16,53%, agresión física (10,43% y accidente de motocicleta (8,84%. Se observó que 23,3% de los atendimientos realizados en la urgencia fueron de la población procedente de municipios aledaños. Hay, por lo tanto, la necesidad de mejorar la calidad de las informaciones acerca de las quejas motivadas por causas externas, principales causas de hospitalización y gastos en salud.

Justicia social y ambiental: mujeres por la soberanía alimentaria

Directory of Open Access Journals (Sweden)

Angelica Velasco Sesma

2010-05-01

Full Text Available Dada la situación de crisis alimentaria, climática, energética y financiera a nivel internacional y el aumento del hambre en el mundo, numerosos movimientos sociales se han unido para luchar por la soberanía alimentaria y por la agricultura campesina. Las mujeres, como sujetos que desempeñan un rol fundamental en la actividad agraria, han manifestado, en la Declaración de las mujeres por la Soberanía Alimentaria, Nyéléni, Mali, 2007, que pretenden unir su lucha por la sostenibilidad con la reivindicación de sus derechos.

Synthesis and properties of ternary (K, NH{sub 4}, H{sub 3}O)-jarosites precipitated from Acidithiobacillus ferrooxidans cultures in simulated bioleaching solutions

Energy Technology Data Exchange (ETDEWEB)

Sandy Jones, F.; Bigham, Jerry M. [School of Environment and Natural Resources, Ohio State University, 2021 Coffey Road, Columbus, OH 43210 (United States); Gramp, Jonathan P. [Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210 (United States); Tuovinen, Olli H., E-mail: tuovinen.1@osu.edu [Department of Microbiology, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210 (United States)

2014-11-01

The purpose of this study was to synthesize a series of solid solution jarosites by biological oxidation of ferrous iron at pH 2.2–4.4 and ambient temperature in media containing mixtures of K{sup +} (0, 1, 4, 6, 12, 31 mM) and NH{sub 4}{sup +} (6.1, 80, 160, 320 mM). The starting material was a liquid medium for Acidithiobacillus ferrooxidans comprised of 120 mM FeSO{sub 4} solution and mineral salts at pH 2.2. Following inoculation with A. ferrooxidans, the cultures were incubated in shake flasks at 22 °C. As bacteria oxidized ferrous iron, ferric iron hydrolyzed and precipitated as jarosite-group minerals (AFe{sub 3}(SO{sub 4}){sub 2}(OH){sub 6}) and/or schwertmannite (idealized formula Fe{sub 8}O{sub 8}(OH){sub 6}(SO{sub 4})·nH{sub 2}O). The precipitates were characterized by X-ray diffraction (XRD), elemental analysis, and Munsell color. Schwertmannite was the dominant mineral product at low combinations of K{sup +} (≤ 4 mM) and NH{sub 4}{sup +} (≤ 80 mM) in the media. At higher single or combined concentrations, yellowish jarosite phases were produced, and Munsell hue provided a sensitive means of detecting minor schwertmannite in the oxidation products. Although the hydrated ionic radii of K{sup +} and NH{sub 4}{sup +} are similar, K{sup +} greatly facilitated the formation of a jarosite phase compared to NH{sub 4}{sup +}. Unit cell and cell volume calculations from refinements of the powder XRD patterns indicated that the jarosite phases produced were mostly ternary (K, NH{sub 4}, H{sub 3}O)-solid solutions that were also deficient in structural Fe, especially at low NH{sub 4} contents. Thus, ferric iron precipitation from the simulated bioleaching systems yielded solid solutions of jarosite with chemical compositions that were dependent on the relative concentrations of K{sup +} and NH{sub 4}{sup +} in the synthesis media. No phase separations involving discrete, end-member K-jarosite or NH{sub 4}-jarosite were detected in the un-aged precipitates

Escenarios de costos generados por el uso del costeo variable

OpenAIRE

Zea Lourido, Felipe

2013-01-01

Este trabajo demuestra cómo el costeo absorbente, considerado por expertos en la materia, uno de los métodos de costeo usado frecuentemente por las organizaciones, con el propósito de determinar el valor de los inventarios y del costo de productos vendidos que intervienen en el estado de resultados para usuarios externos (stakeholders), al compararlo con el costeo variable, preferido por algunos administradores para toma de decisiones internas y usado en la preparación del estado de resultado...

Drug - KEGG MEDICUS | LSDB Archive [Life Science Database Archive metadata

Lifescience Database Archive (English)

Full Text Available [ Credits ] English ]; } else if ( url.search(//en//) != -1 ) { url = url.replace(/...switchLanguage; BLAST Search Image Search Home About Archive Update History Data List Contact us KEGG MEDI...metabolizing enzyme, and other molecular interaction network information. Data file File name: kegg_medi...cus_drug_en.zip File URL: ftp://ftp.biosciencedbc.jp/archive/kegg-medicus/LATEST/kegg_medi...cus_drug_en.zip File size: 5.2 MB Simple search URL http://togodb.biosciencedbc.jp/togodb/view/kegg_medi

Synthesis of copper sulfide nanotube in the hydrogel system

International Nuclear Information System (INIS)

Tan Changhui; Zhu Yulan; Lu Ran; Xue Pengchong; Bao Chunyan; Liu Xinli; Fei Zhuping; Zhao Yingying

2005-01-01

This paper presents a novel method for the preparation of copper sulfide (CuS) nanotubes using hydrogel based on N-lauroylalanine as template under mild condition. The resulting samples are examined by transmission electron microscopy (TEM) FT-IR spectroscopy, X-ray powder diffraction (XRD), UV-vis absorption spectroscopy. It is found that the intermolecular hydrogen bonds play an important role on the formation of the hydrogel and the Cu 2+ coordination gel. The formation process of CuS nanotube is also discussed

Elasticidad precio de la demanda por autopistas interurbanas en Chile

Directory of Open Access Journals (Sweden)

Rodrigo Sanes

2013-01-01

transporte depende de la información que se disponga respecto a la elasticidad precio de la demanda por el uso de puentes, túneles y carreteras. El objetivo de este trabajo es estimar la elasticidad precio de la demanda por el uso de autopistas interurbanas en Chile utilizando el método de regresiones aparentemente no relacionadas (SUR y un panel de 48 datos mensuales obtenidos a partir de 21 plazas de peajes (48 x 21. Nuestros resultados muestran que, aún controlando por el precio de la gasolina y el nivel de actividad económica, la demanda por el uso de carreteras resulta ser muy inelástica al precio del peaje, con valores que oscilan entre -0,17 para automóviles y -0,05 para camiones.

Mortalidad por defectos del tubo neural en México, 1980-1997

Directory of Open Access Journals (Sweden)

Ramírez-Espitia José A

2003-01-01

Full Text Available OBJETIVO: Describir la mortalidad en México por defectos del tubo neural, durante el periodo 1980-1997. MATERIAL Y MÉTODOS: Las tasas anuales de mortalidad estatales y nacionales, por defectos del tubo neural, se calcularon por 10 000 nacidos vivos. La tendencia temporal fue evaluada por el porcentaje de cambio anual obtenido mediante un modelo de regresión de Poisson. Se calculó la razón de mortalidad, tomando la media nacional como referencia. Las tasas y las razones se representaron gráficamente en mapas. RESULTADOS: Durante el periodo la tasa bruta de mortalidad por defectos del tubo neural fue de 5.8 por 10 000 nacidos vivos. La anencefalia fue el tipo de defecto más frecuente (37.7%, seguida de la espina bífida sin hidrocefalia (31.6%. La tendencia nacional de la mortalidad por defectos del tubo neural fue ascendente entre 1980 y 1990 (porcentaje de cambio anual 7.5 IC 95% 6.5, 8.6 y descendente entre 1990-1997 (porcentaje de cambio anual -2.3 IC 95% -3.6, -0.9. CONCLUSIONES: Las altas tasas de mortalidad por defectos del tubo neural fueron debidas principalmente a la elevada frecuencia de las anencefalias. El incremento observado parece no ser sólo atribuible a cuestiones puramente diagnósticas o de mejora en los registros. La influencia de factores asociados a estos defectos, como determinados polimorfismos genéticos, la deficiencia de ácido fólico, la obesidad materna, la exposición laboral a plaguicidas y la pobreza deberán evaluarse mediante estudios específicos.

Stethoscope versus point-of-care ultrasound in the differential diagnosis of dyspnea: a randomized trial.

Science.gov (United States)

Özkan, Behzat; Ünlüer, Erden E; Akyol, Pinar Y; Karagöz, Arif; Bayata, Mehmet S; Akoğlu, Haldun; Oyar, Orhan; Dalli, Ayşe; Topal, Fatih E

2015-12-01

We aimed to determine the accuracies of point-of-care ultrasound (PoCUS) and stethoscopes as part of the physical examinations of patients with dyspnea. Three emergency medicine specialists in each of two groups of ultrasound and stethoscope performers underwent didactic and hands-on training on PoCUS and stethoscope usage. All the patients enrolled were randomized to one of two predetermined PoCUS or stethoscope groups. The diagnostic performance of ultrasonography was higher than that of the stethoscope in the diagnoses of heart failure (90 vs. 86%, 1.00 vs. 0.89, and 5.00 vs. 4.92, respectively) and pneumonia (90 vs. 86.7%, 0.75 vs. 0.73, and 16.50 vs. 13.82, respectively). No significant differences were observed in the utility parameters of these modalities in these diagnoses. Although some authors argue that it is time to abandon the 'archaic tools' of past centuries, we believe that it is too early to discontinue the use of the stethoscope.

Towards identifying the active sites on RuO2(110) in catalyzing oxygen evolution  

DEFF Research Database (Denmark)

Rao, Reshma R.; Kolb, Manuel J.; Halck, Niels Bendtsen

2017-01-01

While the surface atomic structure of RuO2 has been well studied in ultra high vacuum, much less is known about the interaction between water and RuO2 in aqueous solution. In this work, in situ surface X-ray scattering measurements combined with density functional theory (DFT) were used to determ......While the surface atomic structure of RuO2 has been well studied in ultra high vacuum, much less is known about the interaction between water and RuO2 in aqueous solution. In this work, in situ surface X-ray scattering measurements combined with density functional theory (DFT) were used...... on the coordinatively unsaturated Ru sites (CUS) and hydrogen adsorbed to the bridging oxygen sites. At potentials relevant to the oxygen evolution reaction (OER), an –OO species on the Ru CUS sites was detected, which was stabilized by a neighboring –OH group on the Ru CUS or bridge site. Combining potential...

Super-hydrophilic copper sulfide films as light absorbers for efficient solar steam generation under one sun illumination

Science.gov (United States)

Guo, Zhenzhen; Ming, Xin; Wang, Gang; Hou, Baofei; Liu, Xinghang; Mei, Tao; Li, Jinhua; Wang, Jianying; Wang, Xianbao

2018-02-01

Solar steam technology is one of the simplest, most direct and effective ways to harness solar energy through water evaporation. Here, we report the development using super-hydrophilic copper sulfide (CuS) films with double-layer structures as light absorbers for solar steam generation. In the double-layer structure system, a porous mixed cellulose ester (MCE) membrane is used as a supporting layer, which enables water to get into the CuS light absorbers through a capillary action to provide continuous water during solar steam generation. The super-hydrophilic property of the double-layer system (CuS/MCE) leads to a thinner water film close to the air-water interface where the surface temperature is sufficiently high, leading to more efficient evaporation (˜80 ± 2.5%) under one sun illumination. Furthermore, the evaporation efficiencies still keep a steady value after 15 cycles of testing. The super-hydrophilic CuS film is promising for practical application in water purification and evaporation as a light absorption material.

Ependimoma celular parcialmente resecado complicado con meningoependimocoroiditis bacteriana por Pseudomonas aeruginosa e infección sistémica por citomegalovirus

Directory of Open Access Journals (Sweden)

Francisco Javier Otero-Mendoza

2017-06-01

Full Text Available Niño de 1 año 10 meses de edad, originario de Irapuato, Guanajuato, sin antecedentes de importancia para el padecimiento actual. Inició dos meses previos a su ingreso con crisis convulsivas tónico-clónicas generalizadas de 15 segundos de duración durante el sueño. Se realizó electroencefalograma que reportó actividad epileptiforme, por lo que se dio tratamiento con ácido valproico. Una semana previa al ingreso se agregó ataxia troncal impidiendo la marcha, por lo que se realizó una tomografía axial computarizada de cráneo en la que se observó un tumor en fosa posterior con densidad heterogénea y áreas de necrosis central que obliteraba el cuarto ventrículo, ocasionando efecto de masa y desplazamiento ventral del tallo cerebral. Por tal motivo, fue referido a nuestra institución.

Higiene alimentaria para la prevención de trastornos digestivos infecciosos y por toxinas

Directory of Open Access Journals (Sweden)

G. Manuel Moreno, Dr.

2010-09-01

Full Text Available El principal factor que interviene en el origen y prevención de las enfermedades trasmitidas por los alimentos es la higiene alimentaria. Dichas enfermedades son causadas por la ingestión de alimentos o agua contaminados con microorganismos patógenos ocasionando una infección o por la ingestión de alimentos contaminados con toxinas. Los principales agentes involucrados son Escherichia Coli, Campylobacter, Salmonella, Shigella, Listeria Monocytogenes, Norovirus, virus Hepatitis A, Astrovirus, Rotavirus, y Virus Coxsackie. Toxinas producidas por hongos o por microflora marina y los contaminantes orgánicos persistentes pueden también causar serios problemas de salud. La inocuidad alimentaría ha tomado relevancia debido a una mayor exigencia por consumidores cada día más informados y por las demandas del comercio exterior. Medidas que aseguren una adecuada higiene alimentaría nos permitirá prevenir enfermedades, principalmente digestivas, causadas por variados agentes en los alimentos. Esto se logra por la implementación de las medidas propuestas por la Comisión Internacional conocida como Codex Alimentarius.

Endoftalmitis poscirugía de catarata por Sphingomonas paucimobilis

Directory of Open Access Journals (Sweden)

Omar Mauri Garrido

Full Text Available Se presenta la caracterización y manejo terapéutico de un caso de endoftalmitis bacteriana posoperatoria causada por el germen Sphingomonas paucimobilis. La endoftalmitis es la inflamación de los tejidos intraoculares, considerada como la más devastadora de las complicaciones posoperatorias; posee pronóstico visual muy reservado y un elevado riesgo de secuela. Las Sphingomonas paucimobilis son bacterias gramnegativas con forma de bacilo, quimioheterótrofa y estrictamente aerobias que causan enfermedades en los seres humanos, principalmente infecciones hospitalarias que típicamente son tratadas fácilmente con antibióticos. Por sus capacidades biodegradantes y biosintéticas, son pocos los reportes hallados de infección intraocular por este germen. El pronóstico visual es favorable con un diagnóstico precoz y la aplicación del tratamiento adecuado. En este artículo se presentan un caso de endoftalmitis poscirugía de catarata por Sphingomonas paucimobilis reportado en Cuba en el mes de septiembre de 2009.

Eritema multiforme mayor desencadenado por antimicrobianos

Directory of Open Access Journals (Sweden)

Ronaldo de Carvalho Raimundo

2010-03-01

Full Text Available El eritema multiforme, aparece como una enfermedad sistémica con la participación de la piel y las membranas mucosas en relación con varios factores como las infecciones bacterianas o virales, y en particular la administración de drogas, analgésicos y antibióticos en general. Se presenta un paciente masculino de 29 años de edad con eritema multiforme mayor desencadenado por antimicrobianos con la aparición de lesiones vesiculares-bulloso-ulcerosas en las regiones de los labios, encías, la lengua y la mucosa genital en tratamiento de una infección del tracto urinario con norfloxacino 400 mg por una semana. Fue realizado un tratamiento de soporte con el uso de colutorios para la higienización bucal y pomada a base de corticoide para protección de las úlceras, antihistamínicos y orientación nutricional de dieta líquida hipercalórica e hiperproteica. Este síndrome está caracterizado como un proceso eruptivo buloso agudo que compromete la calidad de vida del paciente y no hay pruebas de laboratorio específicas por lo que su diagnóstico debe estar basado en la revisión minuciosa de la anamnesis y en los hallazgos clínicos.

Tendencias de la mortalidad por fiebre amarilla, Colombia, 1998-2009

Directory of Open Access Journals (Sweden)

Ángela María Segura

2013-08-01

Full Text Available Introducción. La fiebre amarilla es una enfermedad tropical desatendida, razón por la cual el conocer las tendencias de mortalidad por fiebre amarilla en Colombia, constituye una importante fuente de información para la toma de decisiones y las intervenciones en salud pública. Objetivo. Analizar las tendencias de mortalidad fiebre amarilla en Colombia (1998-2009 y las diferencias que presentan las fuentes de información de morbilidad y mortalidad en el país, que afectan indicadores como el de letalidad. Materiales y métodos. Es un estudio descriptivo de las muertes por fiebre amarilla, según el Departamento Administrativo Nacional de Estadística, y de la incidencia de la enfermedad, según el Instituto Nacional de Salud. Se usaron fuentes secundarias de información en el cálculo de proporciones de las características sociodemográficas de los fallecidos y las medidas epidemiológicas de letalidad, incidencia y mortalidad por fiebre amarilla, por departamento de residencia de los fallecidos. Resultados. Las muertes por fiebre amarilla se presentan principalmente en hombres, en edad de trabajar, residentes en zonas rurales dispersas, afiliados al régimen vinculado, residentes en las zonas oriental, suroriental, norte y central del país. Se observaron inconsistencias en los informes reportados que afectan el análisis comparativo. Conclusión. Los habitantes de los departamentos ubicados en los territorios nacionales y en Norte de Santander presentan mayor riesgo de enfermar y de morir por fiebre amarilla, pero esta información pudiera estar subestimada, según la fuente de información utilizada en su cálculo.   doi: http://dx.doi.org/10.7705/biomedica.v33i0.698

Industrial refrigeration by absorption/compression; Refrigeracion industrial por absorcion/compresion

Energy Technology Data Exchange (ETDEWEB)

Ayala Delgado, Ramon; Heard, Christopher Lionel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1996-12-31

The use of the absorption/compression refrigeration in the industrial area is analyzed. It is estimated than in Mexico 50% of the food is wasted for lack of refrigeration in the producing centers and by the inefficient distribution system, as well as for the hot climate. The functioning of the absorption refrigeration and the hybrid system absorption/compression which can operate with the two thermodynamic cycles in variable proportions, depending on the specific application, looking for operational advantages and energy efficiency is described. This type of technology could be applied in Mexico due to the lack of industrial refrigeration and to the need of substituting compressors in some companies which have up to 20 years of use [Espanol] Se analiza el uso de la refrigeracion por absorcion/compresion en el area industrial. En Mexico se estima que se desperdicia el 50% de los alimentos por falta de refrigeracion en los centros productores y por el deficiente sistema de distribucion, asi como por el clima calido. Se describe el funcionamiento de la refrigeracion por absorcion y la refrigeracion por absorcion/compresion o sistema hibrido, el cual puede funcionar con los dos tipos de ciclos termodinamicos, en proporciones variables, dependiendo de la aplicacion especifica, buscando ventajas de operacion y eficiencia energetica. Este tipo de tecnologia podria aplicarse en Mexico debido a la falta de refrigeracion industrial y a la necesidad de sustituir compresores en algunas empresas los cuales tienen hasta 20 anos de uso

Industrial refrigeration by absorption/compression; Refrigeracion industrial por absorcion/compresion

Energy Technology Data Exchange (ETDEWEB)

Ayala Delgado, Ramon; Heard, Christopher Lionel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1997-12-31

The use of the absorption/compression refrigeration in the industrial area is analyzed. It is estimated than in Mexico 50% of the food is wasted for lack of refrigeration in the producing centers and by the inefficient distribution system, as well as for the hot climate. The functioning of the absorption refrigeration and the hybrid system absorption/compression which can operate with the two thermodynamic cycles in variable proportions, depending on the specific application, looking for operational advantages and energy efficiency is described. This type of technology could be applied in Mexico due to the lack of industrial refrigeration and to the need of substituting compressors in some companies which have up to 20 years of use [Espanol] Se analiza el uso de la refrigeracion por absorcion/compresion en el area industrial. En Mexico se estima que se desperdicia el 50% de los alimentos por falta de refrigeracion en los centros productores y por el deficiente sistema de distribucion, asi como por el clima calido. Se describe el funcionamiento de la refrigeracion por absorcion y la refrigeracion por absorcion/compresion o sistema hibrido, el cual puede funcionar con los dos tipos de ciclos termodinamicos, en proporciones variables, dependiendo de la aplicacion especifica, buscando ventajas de operacion y eficiencia energetica. Este tipo de tecnologia podria aplicarse en Mexico debido a la falta de refrigeracion industrial y a la necesidad de sustituir compresores en algunas empresas los cuales tienen hasta 20 anos de uso

¿Por qué hay canciones que perduran?

Directory of Open Access Journals (Sweden)

Josune Albisu Barandiaran

2015-11-01

Full Text Available El principal objetivo de este artículo es analizar una canción, Txoria txori, para deducir cuales han sido las principales características que la han convertido en “Himno popular”, permitiéndola perdurar en el tiempo. Dentro de las principales características, dos han sido verdaderamente reseñables: por una parte, la plasticidad, y por otra, la sencillez y estructura clara de la canción.

Manifestaciones oftalmológicas por virus de Epstein-Barr

Directory of Open Access Journals (Sweden)

Adrianne MayulySuñetÁlvarez

Full Text Available Se trata de un paciente masculino de 26 años que acude por disminución brusca de la visión del ojo derecho. Seingresó como una uveítis posterior dada por exudación extensa en área macular del ojo derecho, acompañada de edema del disco óptico, vasculitis aledaña a la lesión y hemorragias dispersas en llama en el polo posterior. La etiología era controversial y, el tratamiento más apropiado era debatible, por lo que se le realizaron estudios como retinografías seriadas, angiografías fluoresceínicas y reacción en cadena de polimerasa a una muestra del humor acuoso, que confirmó la etiología viral; lo que resultó en una agudeza visual final de 0,1. Posterior a 6 meses del cuadro inicial, el paciente presentó queratitis intraestromal en forma numular -que recurre ante episodios de stress-, para desaparecer luego de terapia tópica con antiinflamatorios no esteroideos y esteroideos.La baja incidencia de casos reportados con uveítis posterior por virus de Epstein Barr resulta de un pobre conocimiento de la presentación de la enfermedad, por tanto un retraso en la instauración del tratamiento. En estos casos la prueba de oro es la reacción de cadena de polimerasa.

LUCHA POR LA TIERRA EN EL NORTE DE URUGUAY

Directory of Open Access Journals (Sweden)

Gabriel Oyhantçabal Benelli

2011-12-01

Full Text Available Este artículo analiza la trayectoria de la lucha por la tierra en Bella Unión, una región característica en Uruguay por la producción de caña de azúcar, a través de los movimientos de clase de sus principales protagonistas: los cortadores de caña sindicalizados en la Unión de Trabajadores Azucareros de Artigas (UTAA. El recorrido histórico hace énfasis en dos períodos históricos diferentes: 1961-1973 y 2005-presente. El primero va desde la fundación del sindicato hasta el golpe militar. Se da en un contexto de auge de la lucha de masas en Uruguay en el cual los trabajadores rurales se organizan en la UTAA levantando, entre otras, la bandera de la Reforma Agraria. El segundo período está marcado por la llegada al gobierno nacional del Frente Amplio, una coalición social-demócrata que reactiva la producción de caña de azúcar en Bella Unión. Este cambio supone una oportunidad para las luchas sociales que la UTAA aprovecha con ocupaciones de tierra favoreciendo un proceso de colonización para los trabajadores rurales. Sin embargo el acceso a la tierra genera nuevas contradicciones, y por tanto nuevos desafíos, por los cambios en la forma de subsunción del trabajo al capital.

Riesgos antrópicos generados por la actividad minera

Directory of Open Access Journals (Sweden)

Ana Violeta Argüello Mejía

2013-10-01

Full Text Available Las actividades productivas generan riesgos antrópicos [1] a mediano y largo plazo. La zona de estudio se ubica en las Parroquias de Pomasqui, San Antonio y Calacalí, donde se han producido riesgos debido a las actividades humanas, en este caso, por la explotación de las canteras para abastecer el mercado de la construcción del Distrito Metropolitano de Quito. La investigación propone determinar los riesgos antrópicos generados por la actividad minera. Los pobladores de la zona identifican que la minería artesanal en sus inicios constituyó una fuente de trabajo, donde sus familias también se involucraban. Actualmente, se observa que en la mayoría de las canteras se utiliza maquinaria especializada y no participan los trabajadores de la zona. Los taludes de las canteras son de 80o y 90o grados, generando amenazas para los trabajadores y moradores de las viviendas aledañas. Uno de los mayores impactos es la contaminación del aire, sin embargo, el suelo y los cursos de agua están siendo afectados por los desperdicios que produce la actividad minera. La población, que está expuesta permanentemente al polvo ocasionado por las canteras y al transporte de material, acusa enfermedades de tipo respiratorio. Así mismo, el ruido ocasionado por el transporte constituye una molestia constante para los pobladores.

Celulitis por cuerpo extraño

Directory of Open Access Journals (Sweden)

Miguel B. Carrasco Guzmán

2016-01-01

Full Text Available Las infecciones de la piel y el tejido celular subcutáneo surgen como un grupo importante de afecciones con una alta morbilidad en edades pediátricas, generalmente relacionada con traumatismo y cuerpos extraños. Se presenta el caso de una escolar femenina de 6 años de edad, con síntomas y signos clínicos que sugieren celulitis en el muslo derecho,  por su evolución tórpida se le realizó el estudio ultrasonográfico que confirmó el diagnóstico etiológico de una celulitis secundaria a un traumatismo, provocada por la introducción de un gran cuerpo extraño, que pasó inadvertido para a familia de la menor.

Oral administration of recombinant Neisseria meningitidis PorA genetically fused to H. pylori HpaA antigen increases antibody levels in mouse serum, suggesting that PorA behaves as a putative adjuvant.

Science.gov (United States)

Vasquez, Abel E; Manzo, Ricardo A; Soto, Daniel A; Barrientos, Magaly J; Maldonado, Aurora E; Mosqueira, Macarena; Avila, Anastasia; Touma, Jorge; Bruce, Elsa; Harris, Paul R; Venegas, Alejandro

2015-01-01

The Neisseria meningitidis outer membrane protein PorA from a Chilean strain was purified as a recombinant protein. PorA mixed with AbISCO induced bactericidal antibodies against N. meningitidis in mice. When PorA was fused to the Helicobacter pylori HpaA antigen gene, the specific response against H. pylori protein increased. Splenocytes from PorA-immunized mice were stimulated with PorA, and an increase in the secretion of IL-4 was observed compared with that of IFN-γ. Moreover, in an immunoglobulin sub-typing analysis, a substantially higher IgG1 level was found compared with IgG2a levels, suggesting a Th2-type immune response. This study revealed a peculiar behavior of the purified recombinant PorA protein per se in the absence of AbISCO as an adjuvant. Therefore, the resistance of PorA to proteolytic enzymes, such as those in the gastrointestinal tract, was analyzed, because this is an important feature for an oral protein adjuvant. Finally, we found that PorA fused to the H. pylori HpaA antigen, when expressed in Lactococcus lactis and administered orally, could enhance the antibody response against the HpaA antigen approximately 3 fold. These observations strongly suggest that PorA behaves as an effective oral adjuvant.

Choque cardiogênico por dissulfiram Shockcardiogénico por disulfiram Cardiogenic shock caused by disulfiram

Directory of Open Access Journals (Sweden)

Ana Jerónimo

2009-03-01

Full Text Available A intoxicação medicamentosa por dissulfiram é uma situação rara, mas, que pode se apresentar com manifestações cardiovasculares graves e potencialmente fatais, como choque cardiogênico. É apresentado o caso de uma paciente com choque refratário, após intoxicação voluntária por dissulfiram. A avaliação clínica e bioquímica, junto à avaliação ecocardiográfica e à monitorização invasiva, confirmaram tratar-se de um choque cardiogênico associado a esse fármaco. São discutidos os mecanismos de ação conhecidos do dissulfiram e descritos os principais efeitos colaterais, especialmente os cardiovasculares, alertando para a importância da suspeição diagnóstica e da abordagem terapêutica imediata mais adequada nesse contexto.La intoxicación medicamentosa por disulfiram es una situación rara, aunque puede presentarse con manifestaciones cardiovasculares graves y potencialmente fatales, como el shock cardiogénico. Este relato presenta el caso de una paciente con shock refractario, tras intoxicación voluntaria por disulfiram. La evaluación clínica y bioquímica, junto a la evaluación ecocardiográfica y el monitoreo invasivo, confirmaron tratarse de un shock cardiogénico asociado a ese fármaco. A lo largo del presente relato se discuten los mecanismos de acción del disulfiram conocidos, así como se describen los principales efectos colaterales, específicamente los cardiovasculares. En este sentido, también se alerta para la importancia de la sospecha diagnóstica y del abordaje terapéutico inmediato más adecuado a este contexto.Drug intoxication with disulfiram is a rare condition that may lead to severe and potentially fatal cardiovascular manifestations such as cardiogenic shock. We report the case of a female patient with refractory shock after deliberate self-poisoning with disulfiram. Clinical, biochemical and echocardiographic assessment, as well as invasive monitoring confirmed cardiogenic shock

Elasticidad precio de la demanda por autopistas interurbanas en Chile

Directory of Open Access Journals (Sweden)

Rodrigo Saens

2013-07-01

Full Text Available La efectividad de un esquema de tarificación vial para optimizar el uso de infraestructura de transporte depende de la información que se disponga respecto a la elasticidad precio de la demanda por el uso de puentes, túneles y carreteras. El objetivo de este trabajo es estimar la elasticidad precio de la demanda por el uso de autopistas interurbanas en Chile utilizando el método de regresiones aparentemente no relacionadas (SUR y un panel de 48 datos mensuales obtenidos a partir de 21 plazas de peajes (48 x 21. Nuestros resultados muestran que, aún controlando por el precio de la gasolina y el nivel de actividad económica, la demanda por el uso de carreteras resulta ser muy inelástica al precio del peaje, con valores que oscilan entre -0,17 para automóviles y -0,05 para camiones.

Fiebres hemorrágicas por Arenavirus en Latinoamérica

Directory of Open Access Journals (Sweden)

Ella Soto

2010-01-01

Full Text Available Las fiebres hemorrágicas virales producidas por Arenavirus incluyen a los virus endémicos en África (Lassa y el virus de la coriomeningitis linfocítica (LCMV, de distribución mundial, y los Arenavirus del Nuevo Mundo o Complejo Tacaribe, que incluye a los virus endémicos en las Américas (Junín, Machupo, Guanarito, Sabiá, Pichinde, entre otros. Los huéspedes naturales son los roedores y la infección en humanos se produce por el contacto con la orina y excretas. Las manifestaciones clínicas inicialmente son indistinguibles de otras fiebres hemorrágicas producidas por bacterias, parásitos y otros virus, constituyéndose esto en un problema de salud pública, por lo que se requiere realizar el diagnóstico diferencial utilizando técnicas serológicas y moleculares.

Itinerario de la Patria: por tierras del golfo lejano

Directory of Open Access Journals (Sweden)

Adel López Gómez

1965-06-01

Full Text Available Veinticinco años atrás solo primaba en estas infinitudes el imperio de la selva. Desde Dabeiba tórrido hasta Turbo sudoroso y lacustre se empleaba casi una semana a lomo de mula o a quimba de peatón, por una sombría trocha de miasmas y de lodo, abierta a machete por entre la áspera e interminable manigua. Por allí pasaron una y otra vez los pálidos hombres de nuestros enganches, cuando en 1939 iniciamos, a la orilla del Golfo de Urabá, la ingente tarea de construír una carretera hacia el interior para poner al alcance de las llantas antioqueñas la orilla salvaje del Atlántico maicero.

2015. 2. Por qué celebrar primarias

OpenAIRE

Sanz Díaz, Benito

2015-01-01

¿Por qué celebrar primarias? ¿Beneficia o perjudica a las organizaciones y partidos que las promueven?, ¿Mejora la participación?, ¿La elección de los dirigentes evita la oligarquización y la Ley de Hierro de los partidos políticos que enunció Robert Michels? Un sistema de selección de candidatos con origen en la política norteamericana, fue adaptado por el PSOE, y a continuación iría extendiéndose su práctica a los todos los partidos políticos. Ignacio Urquizu señalaba sobre l...

Cidades sutis: dispersão urbana e da rede de saúde mental

Directory of Open Access Journals (Sweden)

Luis Artur Costa

2013-01-01

Full Text Available Este artigo pretende problematizar o percurso genealógico que possibilita o atual arranjo entre a cidade de Porto Alegre e sua assistência em saúde mental. Inicia com a cidade e seu Hospital Psiquiátrico São Pedro, constituídos a partir de uma lógica disciplinar que buscava subjetivar corpos e gestos adequados para o trabalho industrial e aos padrões de convivência da civilidade urbana moderna. Vemos então o surgimento de movimentos anômalos a esta geometria, espasmos descentralizantes que vão esboroando as antigas centralidades e seus lócus antes fechados. Através da breve genealogia dos movimentos que tomaram tais espaços, operamos a problematização das transformações nesta cidade e nas atuais práticas de assistência à saúde mental: por um lado, as novas microssegmentações privadas no espaço urbano contemporâneo minando a centralidade urbana da cidade com a dispersão da convivência e, por outro, a atual reforma psiquiátrica, com a descentralização da assistência.

14 Nobel, preocupados por el CERN

CERN Multimedia

Rivera, A

2003-01-01

"E l presidente del Consejo del CERN (Laboratorio Europeo de Fisica de Particulas, junto a Ginebra), Maurice Bourquin, ha recibido una carta firmada por un grupo de cientificos muy especiales: 14 premios Nobel de Fisica" (1 page).

Mortalidad intrahospitalaria por accidente cerebrovascular

Directory of Open Access Journals (Sweden)

Federico Rodríguez Lucci

2013-08-01

Full Text Available La mortalidad global por accidente cerebrovascular (ACV ha disminuido en las últimas tres décadas, probablemente debido a un mejor control de los factores de riesgo vascular. La mortalidad hospitalaria por ACV ha sido tradicionalmente estimada entre 6 y 14% en la mayoría de las series comunicadas. Sin embargo, los datos de ensayos clínicos recientes sugieren que esta cifra sería sustancialmente menor. Se revisaron datos de pacientes internados con diagnóstico de ACV del Banco de Datos de Stroke de FLENI y los registros institucionales de mortalidad entre los años 2000 y 2010. Los subtipos de ACV isquémicos se clasificaron según criterios TOAST y los ACV hemorrágicos en hematomas intrapanquimatosos, hemorragias subaracnoideas aneurismáticas, malformaciones arteriovenosas y otros hematomas intraparenquimatosos. Se analizaron 1514 pacientes, 1079 (71% con ACV isquémico (grandes vasos 39%, cardioembólicos 27%, lacunares 9%, etiología indeterminada 14%, otras etiologías 11% y 435 (29% con ACV hemorrágico (intraparenquimatosos 27%, hemorragia subaracnoidea 30%, malformaciones arteriovenosas 25% y otros hematomas espontáneos 18%. Se registraron 38 muertes intrahospitalarias (17 ACV isquémicos y 21 ACV hemorrágicos, representando una mortalidad global del 2.5% (1.7% en ACV isquémicos y 4.8% en ACV hemorrágicos. No se registraron muertes asociadas al uso de fibrinolíticos endovenosos. La mortalidad intrahospitalaria en pacientes con ACV isquémico y hemorrágico en nuestro centro fue baja. El manejo en un centro dedicado a las enfermedades neurológicas y el enfoque multidisciplinario por personal médico y no médico entrenado en el cuidado de la enfermedad cerebrovascular podrían explicar, al menos en parte, estos resultados.

¿Por qué el satélite Cóndor?

Directory of Open Access Journals (Sweden)

Leonardo Ferrerira

2015-01-01

Full Text Available Estados Unidos y Rusia representan el 15 por ciento de la población mundial sin embargo utilizan el 50 por ciento de la órbita geoestacionaria, mientras todo el Tercer Mundo emplea menos del 10 por ciento. Los países del Pacto Andino se encuentran trabajando conjuntamente en el uso compartido de un solo sistemas satelital CONDOR. Pero los críticos norteamericanos consideran que es una manera ineficiente e irracional congestionar el espectro orbital. El artículo se centra en describir este proyecto y la lógica Andina, la soberanía

Hipoglucemia inducida por carcinoma adrenal

Directory of Open Access Journals (Sweden)

Jimena Soutelo

2013-08-01

Full Text Available El carcinoma suprarrenal es una neoplasia maligna infrecuente y de mal pronóstico. La presentación clínica más común es originada por la producción hormonal excesiva, mientras que el desarrollo de hipoglucemia sintomática es excepcional. Presentamos el caso de una mujer de 37 años que ingresó al hospital por síntomas de hipoglucemias graves, hipertensión arterial, hipopotasemia y amenorrea secundaria. En el laboratorio se halló hipoglucemia con insulina inhibida y niveles de andrógenos en rango tumoral. La tomografía computarizada (TC de abdomen y pelvis mostró voluminosa formación heterogénea de aspecto sólido sin plano de clivaje con respecto al parénquima hepático e intenso realce con contraste. Luego de la extirpación de la masa retroperitoneal, evolucionó con valores de glucemia y potasemia normales, estabilizó la presión arterial y recuperó los ciclos menstruales.

Cefaleia por uso excessivo de medicamentos

Directory of Open Access Journals (Sweden)

Ariane Maria Fonseca MIRANDA

2015-01-01

Full Text Available Uma variante da cefaleia crônica diária, a cefaleia por uso excessivo de medicamentos é uma manifestação clínica de frequência ≥ 15 dias por mês, durante 3 meses. Possui um diagnóstico deficiente e um tratamento dividido em etapas, sendo a desintoxicação, a etapa de fundamental importância. Este artigo apresenta uma revisão sobre o tema, contribuindo para o esclarecimento das principais manifestações clínicas, principais teorias envolvendo sua fisiopatologia e a terapêutica farmacológica empregada. A metodologia utilizada foi uma revisão de publicações europeias e americanas, no período de 2001 a 2013, nos idiomas português, inglês e espanhol. Todos os medicamentos utilizados no tratamento sintomático das cefaleias são capazes de cronificar uma cefaleia preexistente, desde que sejam utilizados excessivamente, de forma regular e continuada. A suspensão de tais agentes terapêuticos resultará em melhoria na maioria dos pacientes, porém pode ser necessária a introdução de uma terapia de suporte de transição e/ou terapia profilática. Os tratamentos nao farmacológicos, quando associados ao farmacológico, ampliam a possibilidade de resultados satisfatórios, evitando recaídas.

Experimental studies on possible regulatory role of nitric oxide on the differential effects of chronic predictable and unpredictable stress on adaptive immune responses.

Science.gov (United States)

Thakur, Tarun; Gulati, Kavita; Rai, Nishant; Ray, Arunabha

2017-09-01

The present study was designed to investigate the effects of chronic predictable stress (CPS) and chronic unpredictable stress (CUS) on immunological responses in KLH-sensitized rats and involvement of NOergic signaling pathways mediating such responses. Male Wistar rats (200-250g) were exposed to either CPS or CUS for 14days and IgG antibody levels and delayed type hypersensitivity (DTH) response was determined to assess changes in adaptive immunity. To evaluate the role of nitric oxide during such immunomodulation, biochemical estimation of stable metabolite of nitric oxide (NOx) and 3-nitrotyrosine (3-NT, a marker of peroxynitrite formation) were done in both blood and brain. Chronic stress exposure resulted in suppression of IgG and DTH response and elevated NOx and 3-NT levels, with a difference in magnitude of response in CPS vs CUS. Pretreatment with aminoguanidine (iNOS inhibitor) caused further reduction of adaptive immune responses and attenuated the increased NOx and 3-NT levels in CPS or CUS exposed rats. On the other hand 7-NI (nNOS inhibitor) did not significantly affect these estimated parameters. The results suggest involvement of iNOS and lesser/no role of nNOS during modulation of adaptive immunity to stress. Thus, the result showed that predictability of stressors results in differential degree of modulation of immune responses and complex NO-mediated signaling mechanisms may be involved during responses. Copyright © 2017. Published by Elsevier B.V.

Dynamic Hydrogen Production from Methanol/Water Photo-Splitting Using Core@Shell-Structured CuS@TiO2 Catalyst Wrapped by High Concentrated TiO2 Particles

Directory of Open Access Journals (Sweden)

Younghwan Im

2013-01-01

Full Text Available This study focused on the dynamic hydrogen production ability of a core@shell-structured CuS@TiO2 photocatalyst coated with a high concentration of TiO2 particles. The rectangular-shaped CuS particles, 100 nm in length and 60 nm in width, were surrounded by a high concentration of anatase TiO2 particles (>4~5 mol. The synthesized core@shell-structured CuS@TiO2 particles absorbed a long wavelength (a short band gap above 700 nm compared to that pure TiO2, which at approximately 300 nm, leading to easier electronic transitions, even at low energy. Hydrogen evolution from methanol/water photo-splitting over the core@shell-structured CuS@TiO2 photocatalyst increased approximately 10-fold compared to that over pure CuS. In particular, 1.9 mmol of hydrogen gas was produced after 10 hours when 0.5 g of 1CuS@4TiO2 was used at pH = 7. This level of production was increased to more than 4-fold at higher pH. Cyclic voltammetry and UV-visible absorption spectroscopy confirmed that the CuS in CuS@TiO2 strongly withdraws the excited electrons from the valence band in TiO2 because of the higher reduction potential than TiO2, resulting in a slower recombination rate between the electrons and holes and higher photoactivity.

Primer reporte de un caso importado de Malaria por Plasmodium ovale curtisi en Paraguay, confirmado por diagnóstico molecular

Directory of Open Access Journals (Sweden)

Florencia del Puerto

2015-04-01

Full Text Available En países donde el Plasmodium ovale no es común, los microscopistas tienden a identificarlo de manera errónea como Plasmodium vivax. En este trabajo reportamos la identificación de la especie P. ovale curtisi por el método de PCR múltiple semianidada (SnM-PCR y la secuenciación de la subunidad pequeña del gen del ARN 18S, en un paciente paraguayo de 44 años de edad que vino en el 2.013 de Guinea Ecuatorial, África Occidental, a quien se le diagnosticó una infección por P. vivax por microscopía convencional. El empleo de métodos moleculares para la identificación de casos importados de infección con especies del género Plasmodium es uno de los objetivos principales en el control y la prevención de la malaria en Paraguay, teniendo en cuenta que el país se encuentra en fase de pre-eliminación de la enfermedad.

Contractura axilar por quemadura tratada con Integra®

OpenAIRE

Roa G,Ricardo; Las Heras F,Rocío; Piñeros B,José L; Correa S,Gerardo; Norambuena B,Hernán; Marré N,Diego

2011-01-01

Las quemaduras axilares severas son un accidente infrecuente que evolucionan a la retracción generando deficiencias cosméticas y funcionales. Estas cicatrices son difíciles de tratar por las características anatómicas del área, donde la corrección de un vector de movimiento puede alterar otro. Objetivo: Mostrar nuestros resultados utilizando el sustituto cutáneo Integra® en el tratamiento de cicatrices retráctiles axilares por quemadura. Pacientes y Métodos: Se recolectaron antecedentes médic...

Analysis of early bacterial communities on volcanic deposits on the island of Miyake (Miyake-jima), Japan: a 6-year study at a fixed site.

Science.gov (United States)

Fujimura, Reiko; Sato, Yoshinori; Nishizawa, Tomoyasu; Nanba, Kenji; Oshima, Kenshiro; Hattori, Masahira; Kamijo, Takashi; Ohta, Hiroyuki

2012-01-01

Microbial colonization on new terrestrial substrates represents the initiation of new soil ecosystem formation. In this study, we analyzed early bacterial communities growing on volcanic ash deposits derived from the 2000 Mount Oyama eruption on the island of Miyake (Miyake-jima), Japan. A site was established in an unvegetated area near the summit and investigated over a 6-year period from 2003 to 2009. Collected samples were acidic (pH 3.0-3.6), did not utilize any organic substrates in ECO microplate assays (Biolog), and harbored around 106 cells (g dry weight)(-1) of autotrophic Fe(II) oxidizers by most-probable-number (MPN) counts. Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, and the Leptospirillum groups I, II and III were found to be abundant in the deposits by clone library analysis of bacterial 16S rRNA genes. The numerical dominance of Acidithiobacillus ferrooxidans was also supported by analysis of the gene coding for the large subunit of the form I ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Comparing the 16S rRNA gene clone libraries from samples differing in age, shifts in Fe(II)-oxidizing populations seemed to occur with deposit aging. The detection of known 16S rRNA gene sequences from Fe(III)-reducing acidophiles promoted us to propose the acidity-driven iron cycle for the early microbial ecosystem on the deposit.

¿Por qué fracasan las campañas?

Directory of Open Access Journals (Sweden)

Andrea Castelnuovo

2015-01-01

Full Text Available Analiza tres experiencias en las que puede evidenciarse por qué fracasan las campañas sociales: por la misma razón, fueron concebidas con mensajes destinados a una población que vive y percibe el mundo desde el nivel económico y socio-cultural distinto, el emisor no empata con los perfiles del receptor. Es fundamental empezar por definir qué se debe decir, a quién, y cómo, para luego encontrar los medios más adecuados para su difusión. La espectacularidad y etnocentrismo, las campañas sociales seguirán sirviendo exclusivamente para mejorar las finanzas de los medios de comunicación masivos y secundariamente, para brindar materia prima a humoristas y contestarios.

Estudo dos linfócitos circulantes por anticorpos monoclonais na miastenia grave

Directory of Open Access Journals (Sweden)

Paulo E. Marchiori

1988-09-01

Full Text Available Os autores avaliam os linfócitos T (CD3, CD4, CD8, CD4/8 por anticorpos monoclonais e rosácea em 20 pacientes e linfócitos B por Fab' por imunofluorescência em 9 pacientes com miastenia grave. Observam elevação significante na população de linfócito B e redução nos linfócitos T totais CD3+ por rosáceas. Não foram observadas modificações nas subpopulações celulares com timectomia e corticosteróides.

México en la segunda Guerra Mundial visto por la Diplomacia venezolana

OpenAIRE

Silva L, Dómel

2013-01-01

Partiendo del análisis de una serie de documentos concernientes a las comunicaciones entre la llamada “Legación de Venezuela” en México y la Cancillería de Venezuela durante los años de la Segunda Guerra Mundial (1939-1945), se esbozará las estrategias en común para ambas naciones; como fue la política de seguridad de cada Estado, enmarcada dentro de la política de seguridad continental. México por su importancia geoestratégica; por el petróleo, por su cercanía con los Estados Unidos y por la...

Osteomalacia inducida por tumor: hemangiopericitoma rinosinusal Tumor-induced osteomalacia: rhinosinusal hemangiopericytoma

Directory of Open Access Journals (Sweden)

Enriqueta M. Serafini

2013-02-01

Full Text Available La osteomalacia inducida por tumor es una rara enfermedad del metabolismo óseo caracterizada por el aumento en la excreción de fosfato a nivel renal seguido de hipofosfatemia. Es causada por agentes fosfatúricos producidos por determinados tumores. La resección total del tumor resulta en la completa reversión de las anormalidades bioquímicas, la desaparición de las manifestaciones clínicas y los hallazgos en los estudios por imágenes. Presentamos el caso de un varón de 61 años con cuadro clínico y laboratorio compatibles con osteomalacia oncogénica inducida por tumor mesenquimático de localización rinosinusal. En nuestro caso el diagnóstico histológico correspondió a una neoplasia de tipo vascular: hemangiopericitoma.Tumor-induced osteomalacia is a rare disease of bone metabolism. The characteristic of this disease is an increase in phosphate excretion followed by hypophosphatemia, due to phosphaturic agents produced by different types of tumors. Tumor resection results in complete resolution of clinical, biochemical and radiological abnormalities. We present the case of a 61 year old man with signs, symptoms and laboratory findings consistent with oncogenic osteomalacia due to a rhino-sinusal mesenchymal tumor. The histological diagnosis showed a vascular neoplasm: hemangiopericytoma.

Disfunção ventricular esquerda transitória por cardiomiopatia induzida por estresse Transient left ventricular dysfunction due to stress-induced cardiomyopathy

Directory of Open Access Journals (Sweden)

Marcus Vinicius Simões

2007-10-01

Full Text Available Apresenta-se o caso de uma paciente de 71 anos que preencheu os critérios diagnósticos para cardiomiopatia induzida por estresse que foi desencadeada por intenso estresse emocional após atropelamento por bicicleta. O quadro clínico mimetizou o infarto agudo do miocárdio, manifestando-se com dor precordial, supradesnivelamento do segmento ST, seguido por ondas T profundas e prolongamento do intervalo QT, elevação discreta de enzimas cardíacas e cursando com disfunção sistólica apical do ventrículo esquerdo e hipercinesia das porções basais (conferindo o aspecto de "abaloamento apical", mas na ausência de obstrução coronariana subepicárdica. A função ventricular normalizou-se após a segunda semana de evolução.The case presented here is of a 71-yr-old female patient who met the diagnostic criteria for stress-induced cardiomyopathy, which was triggered by intense emotional stress after being hit by a bicycle. The clinical picture mimicked that of an acute myocardial infarction, manifesting as precordial pain, ST-segment depression followed by deep negative T waves and prolonging of the QT interval, slight increase in cardiac enzymes and coursing with transient apical ballooning of the left ventricle and hyperkinesis of the basal walls (conferring the aspect of "apical ballooning", although in the absence of subepicardial coronary obstruction. Ventricular function normalized after the second week of clinical evolution.

Evaluation of Various Organic Fertilizer Substrates and Hydraulic Retention Times for Enhancing Anaerobic Degradation of Explosives-Contaminated Groundwater While Using Constructed Wetlands at the Milan Army Ammunition Plant, Milan, Tennessee.

Science.gov (United States)

1998-05-01

Sulfate Solution By Volume: In a 1 L volumetric flask, dissolve 20 g copper sulfate pentahydrate (CuS04 • 5H20) in about 800 mL water. Dilute to mark with...water. Invert to mix thoroughly. By Weight: To a 1 L container, add 20 g copper sulfate pentahydrate (CuS04 • 5H20) to 991 g water. Stir or shake...100 mL portion of 2% copper sulfate solution (reagent 5) to the cadmium prepared above. Swirl for about 5 minutes, then decant the liquid and

Mortalidad por suicidio en la provincia de Pinar del Río

Directory of Open Access Journals (Sweden)

Ana Carmen Valdés Vento

2003-02-01

Full Text Available Se trata de una investigación descriptiva y retrospectiva sobre el comportamiento de la mortalidad por suicidio en la provincia Pinar del Río durante el año 2001, de acuerdo con una serie de variables seleccionadas. Se estudiaron todos los fallecidos por esa causa en el período señalado, que fueron un total de 110 para una tasa de 14,9 por 100 000 habitantes, por lo que es la séptima causa de muerte en la provincia. Llama la atención el amplio predominio del sexo masculino, de la incidencia en la tercera edad, y el hecho de no haber tenido este año el municipio Sandino fallecido alguno por esta causa, así como que el municipio de mayor número de fallecidos por este motivo fue Viñales con una tasa de 26,0 por 100 000 habitantes.A retrospective descriptive research work on the situation of mortality from suicide in Pinar del Río province during 2001 was carried out based on a group of selected variables. All the deaths form this cause, which amounted to 110 persons for a rate of 14.9 per 100 000 pop, were studied. Suicide was the seventh cause of death in the province. It should be underlined that males prevailed, the incidence of the elderly was high and that Sandino municipality had no death from suicide in this year whereas Viñales municipality showed the highest number of deceased, with a mortality rate of 26 per 100 000 pop.

Lucro por ação

Directory of Open Access Journals (Sweden)

Gabriel Moreira Campos

2001-08-01

Full Text Available Este trabalho tem por objetivo demonstrar os principais conceitos acerca do Lucro por Ação (Earnings per Share, o qual se apresenta como um quociente de grande utilidade nas entidades. Serão demonstrados aspectos sobre o assunto presentes no Brasil, bem como as normas aplicáveis nos Estados Unidos, emanadas do Financial Accounting Standards Board (FASB, e as normas internacionais, emanadas do International Accounting Standards Committee (IASC. De forma a possibilitar uma visualização mais completa dos conceitos envolvidos, serão desenvolvidos exemplos de sua aplicação. O Lucro (Resultado por Ação pode ser calculado em sua forma básica e em sua forma diluída. Na forma básica, não são considerados os efeitos dos instrumentos potencialmente dilutivos, ao passo que, no cálculo do Lucro (Resultado por Ação Diluído, são. Como instrumentos financeiros potencialmente dilutivos temos as ações preferenciais conversíveis, as debêntures conversíveis e os bônus de subscrição, que podem ser convertidos em ações ordinárias, caracterizando, assim, o próprio potencial dilutivo desses instrumentos. Dessa forma, o trabalho em questão foi dividido em três partes principais, sendo que nas duas últimas constam os referidos exemplos de cálculo do Lucro por Ação em sua forma básica e em sua forma diluída: • aspectos observados no Brasil; • normas emanadas do FASB; • normas emanadas do IASC.The objective of this paper is to demonstrate the principal concepts about Earnings per Share, which is presented as a quotient of great usefulness for the companies. The subject is presented in three parts: in the first part, we will demonstrate relevant aspects that are present in Brazil. In the second part, the applicable standards in the United States will be discussed, which are issued by the Financial Accounting Standards Board (FASB. In the third part, the international standards are dealt with, which are issued by the

Síndrome oculoglandular de Parinaud causada por esporotricose

OpenAIRE

Ribeiro,Alexandre Sampaio de Abreu; Bisol,Tiago; Menezes,Marcela Sant'Ana

2010-01-01

A síndrome oculoglandular de Parinaud é uma doença ocular rara causada por diferentes agentes etiológicos, entre eles bactérias, vírus e fungos. É caracterizada por uma conjuntivite granulomatosa, acompanhada de linfadenopatia pré-auricular adjacente e pode trazer sequelas caso não seja prontamente tratada. Neste artigo é relatado o caso de uma jovem técnica de enfermagem e estudante de medicina veterinária apresentando a síndrome oculoglandular de Parinaud causada pelo fungo Sporothrix schen...

Por qué todas las cuentas son falsas

OpenAIRE

Aerde, Michel van

1994-01-01

Los principales criterios para evaluación y decisión, en la sociedad actual, son inspirados por cálculos económicos. Mucho nos preocupamos de cuentas pero muy poco nos preguntamos de lo que es el dinero. Muy poco reflexionamos filosóficamente, ontológicamente, sobre la naturaleza misma del dinero. ¿Qué es esto que pretende ser la base de nuestra sociedad? El dinero es mentiroso por naturaleza. Es una representación de mucha vida, que no puede ser representada. El dinero es peligroso, se convi...

Alteraciones hepáticas inducidas por la nutrición parenteral

OpenAIRE

J Salas Salvado; A Recaséns Garica

1993-01-01

Liver disorders induced by parenteral nutrition Alteraciones hepáticas inducidas por la nutrición parenteral Liver disorders induced by parenteral nutrition Alteraciones hepáticas inducidas por la nutrición parenteral

Úlceras por presión causadas por dispositivos clínicos

OpenAIRE

Iglesias Ruisánchez, Sandra

2017-01-01

Las úlceras por presión (UPP) son lesiones comunes en los pacientes hospitalizados, especialmente en las unidades de cuidados intensivos (UCI). Los enfermos críticos tienen un riesgo elevado de desarrollar UPP, debido principalmente a la limitación de la movilidad, disminuyendo su capacidad para cambiar activamente su posición en la cama o asiento. Además, el efecto de fármacos anestésicos y sedantes, puede causar una pérdida de la percepción sensorial cutánea. Los diferentes dispositivos clí...

Análise da prevenção e tratamento das úlceras por pressão propostos por enfermeiros Análisis de la prevención y del tratamiento de las úlceras por presión propuesto por enfermeros Analysis of prevention and treatment of the pressure ulcers proposed by nurses

Directory of Open Access Journals (Sweden)

Adriana Bessa Fernandes Medeiros

2009-03-01

Full Text Available A úlcera por pressão ainda é considerada um problema grave, especialmente em pessoas idosas e nas situações de adoecimento crônico-degenerativo. O objetivo do estudo consistiu em identificar as produções bibliográficas sobre ações de prevenção e tratamento realizadas por enfermeiros publicadas no período de 1999 a 2004, descrevendo o conhecimento produzido na temática. Trata-se de levantamento bibliográfico descritivo de periódicos de enfermagem indexados na LILACS e MEDLINE, acerca da temática no período de 1999 a 2004. A coleta de dados ocorreu entre os meses de maio a junho de 2005. Procedeu-se o exame do material que compreendeu leitura exaustiva, o que proporcionou a identificação de três aspectos estudados: prevenção das úlceras por pressão, tratamento das úlceras por pressão e cuidados de enfermagem às úlceras por pressão. Concluiu-se ainda a necessidade de pesquisas envolvendo a atuação do enfermeiro na avaliação clínica do cliente e no desenvolvimento de programas de prevenção sistematizados.La úlcera por presión, es todavía considerado un problema grave, especialmente en personas ancianas y en las situaciones de enfermedades crónicas degenerativas. El objetivo del estudio consistió en identificar las producciones bibliográficas sobre las acciones de prevención y tratamiento realizadas por enfermeros y publicadas en el período de 1999 a 2004, describiendo el conocimiento producido sobre el tema. Se trata de levantamiento bibliográfico descriptivo de periódicos de enfermería indexados en el LILACS y MEDLINE, acerca de la temática, en el período de 1999 a 2004. La recolección de datos se realizó entre los meses de mayo a junio de 2005. Se procedió a examinar el material con una lectura exhaustiva, lo que proporcionó la identificación de tres aspectos estudiados: prevención de las úlceras por presión, tratamiento de las úlceras por presión y cuidados de enfermería de las

Intoxicação por monofluoroacetato em animais

Directory of Open Access Journals (Sweden)

Vivian Assunção Nogueira

2011-10-01

Full Text Available O monofluoroacetato (MF ou ácido monofluoroacético é utilizado na Austrália e Nova Zelândia no controle populacional de mamíferos nativos ou exóticos. O uso desse composto é proibido no Brasil, devido ao risco de intoxicação de seres humanos e de animais, uma vez que a substância permanece estável por décadas. No Brasil casos recentes de intoxicação criminosa ou acidental têm sido registrados. MF foi identificado em diversas plantas tóxicas, cuja ingestão determina "morte súbita"; de bovinos na África do Sul, Austrália e no Brasil. O modo de ação dessa substância baseia-se na formação do fluorocitrato, seu metabólito ativo, que bloqueia competitivamente a aconitase e o ciclo de Krebs, o que reduz produção de ATP. As espécies animais têm sido classificadas nas quatro Categorias em função do efeito provocado por MF: (I no coração, (II no sistema nervoso central (III sobre o coração e sistema nervoso central ou (IV com sintomatologia atípica. Neste trabalho, apresenta-se uma revisão crítica atualizada sobre essa substância. O diagnóstico da intoxicação por MF é realizado pelo histórico de ingestão do tóxico, pelos achados clínicos e confirmado por exame toxicológico. Uma forma peculiar de degeneração hidrópico-vacuolar das células epiteliais dos túbulos uriníferos contorcidos distais tem sido considerada como característica dessa intoxicação em algumas espécies. O tratamento da intoxicação por MF é um desafio, pois ainda não se conhece um agente capaz de reverte-la de maneira eficaz; o desfecho geralmente é fatal

positivismo por su reduccionismo epistemológico

Directory of Open Access Journals (Sweden)

Ignacio M. Ibarzábal

2007-01-01

Full Text Available A lo largo de la historia humana puede observarse la constante oscilación entre diversas teorías científicas. Esto puede demostrarse, por ejemplo, a partir de una reflexión sobre la evolución de las ideas filosóficas desde fines de la edad Media hasta la actualidad. este fenómeno no hace más que poner de relieve cierta inseguridad connatural al hombre, que genera la opción por soluciones simplistas, y “puras”, lo que culmina en muchos casos en una aproximación reduccionista a la realidad. El problema científico que plantea el reduccionismo epistemológico es que éste, al desentenderse de la realidad existencial del hombre, es incapaz de darle respuestas satisfactorias para resolver conflictos. Este inconveniente lo sufre el positivismo jurídico –así como también lo ha padecido el iusnaturalismo ingenuo–, por su imposibilidad de resolver conflictos jurídicos reales; y esto, a causa de su pretendida aproximación avalorativa que da lugar a dos especies de reduccionismos: el que desconoce tajantemente las valoraciones, y aquél que, reconociéndolas, escoge de manera arbitraria los valores objeto de su conocimiento.

5-HT2A receptor deficiency alters the metabolic and transcriptional, but not the behavioral, consequences of chronic unpredictable stress

Directory of Open Access Journals (Sweden)

Minal Jaggar

2017-12-01

Full Text Available Chronic stress enhances risk for psychiatric disorders, and in animal models is known to evoke depression-like behavior accompanied by perturbed neurohormonal, metabolic, neuroarchitectural and transcriptional changes. Serotonergic neurotransmission, including serotonin2A (5-HT2A receptors, have been implicated in mediating specific aspects of stress-induced responses. Here we investigated the influence of chronic unpredictable stress (CUS on depression-like behavior, serum metabolic measures, and gene expression in stress-associated neurocircuitry of the prefrontal cortex (PFC and hippocampus in 5-HT2A receptor knockout (5-HT2A−/− and wild-type mice of both sexes. While 5-HT2A−/− male and female mice exhibited a baseline reduced anxiety-like state, this did not alter the onset or severity of behavioral despair during and at the cessation of CUS, indicating that these mice can develop stress-evoked depressive behavior. Analysis of metabolic parameters in serum revealed a CUS-evoked dyslipidemia, which was abrogated in 5-HT2A−/− female mice with a hyperlipidemic baseline phenotype. 5-HT2A−/− male mice in contrast did not exhibit such a baseline shift in their serum lipid profile. Specific stress-responsive genes (Crh, Crhr1, Nr3c1, and Nr3c2, trophic factors (Bdnf, Igf1 and immediate early genes (IEGs (Arc, Fos, Fosb, Egr1-4 in the PFC and hippocampus were altered in 5-HT2A−/− mice both under baseline and CUS conditions. Our results support a role for the 5-HT2A receptor in specific metabolic and transcriptional, but not behavioral, consequences of CUS, and highlight that the contribution of the 5-HT2A receptor to stress-evoked changes is sexually dimorphic. Keywords: 5-HT2A−/− mice, Prefrontal cortex, Hippocampus, Gene expression, Sexual dimorphism, Despair

Sea urchin granuloma Granulomas por ouriços-do-mar

Directory of Open Access Journals (Sweden)

André Luiz Rossetto

2006-10-01

Full Text Available Injuries caused by venomous and poisonous aquatic animals may provoke important morbidity in humans. The phylum Echinoderma include more than 6000 species of starfish, sea urchins, sand dollars, and sea cucumbers some of which have been found responsible for injuries to humans. Initial injuries by sea urchins are associated with trauma and envenomation, but later effects can be observed. Sea urchin granuloma is a chronic granulomatous skin disease caused by frequent and successive penetration of sea urchin spines which have not been removed from wounds. The authors report a typical case of sea urchin granuloma in a fisherman and its therapeutic implications.Os acidentes por animais aquáticos traumatizantes e venenosos podem provocar morbidez importante em humanos. Equinodermos marinhos incluem mais de 6000 espécies de estrelas-do-mar, ouriços-do-mar, "bolachas-de-praia" e pepinos-do-mar. Vários equinodermos têm sido responsabilizados por acidentes em humanos. Granulomas por ouriço-do-mar são lesões de caráter granulomatoso, crônicas, causada por acidentes com espículas de ouriço-do-mar. Os autores relatam um caso típico de granulomas por ouriço-do-mar ocorrido em um pescador e enfatizam as implicações terapêuticas aplicadas.

Indultos concedidos por la Cámara de Castilla en tiempos de los Austrias

Directory of Open Access Journals (Sweden)

José Luis de las HERAS SANTOS

2009-12-01

Full Text Available Maquiavelo aconsejaba a los príncipes que se reservaran para sí la disposición de las materias de gracia. Este principio nunca fue olvidado por los reyes castellanos que consideraron el derecho de perdonar como una regalía. A lo largo del Antiguo Régimen se concedieron perdones reales por motivos diversos: políticos, religiosos, acontecimientos cortesanos, triunfos militares de la monarquía, o merced especial que el soberano deseó hacer a algún subdito. Por el número de afectados pueden clasificarse en generales, si absuelven a un colectivo de reos, o particulares, cuando el agraciado es uno solo. Los generales se regulaban por cédula específica que el rey despachaba al efecto. Su cumplimiento era vigilado por comisiones formadas por miembros de la Cámara, y los aspirantes a sus beneficios no necesitaban presentar solicitud personal ante ningún consejo regio, sino que siendo el caso de los incluidos en la cédula, las justicias de la causa se encargaban de su ejecución. Por está razón este tipo de indultos no han dejado huella en los archivos centrales, salvo las cédulas de concesión. Por el contrario, los individuales eran despachados por la Cámara en nombre del rey después de estudiar los autos procesales y han dejado en los archivos de la corona miles de testimonios. Estos van a ser el objeto de nuestro estudio.

Aumento de consultas en atención primaria por infección respiratoria de vías altas y por fiebre coincidiendo con la gripe (H1N1 2009

Directory of Open Access Journals (Sweden)

Pablo Aldaz

2011-01-01

Full Text Available Fundamento: En verano de 2009 se registró en Navarra una onda de gripe A (H1N1 2009. Evaluar su repercusión en consultas de atención primaria con diagnóstico diferente al de gripe. Métodos: Estudiamos las consultas en atención primaria del Servicio Navarro de Salud desde el 21 de junio y al 21 de septiembre de 2009 con diagnósticos de gripe (Clasificación Internacional de Atención Primaria, código R80, síndrome febril (código A03, infección respiratoria aguda de vías altas (código R74 y bronquitis aguda (código R78, y las comparamos con las registradas en el mismo periodo en los tres años previos. Resultados: En verano de 2009 se notificaron 3417 casos de síndrome gripal (5,5 por 1.000 habitantes. Entre las semanas 27 y 31 se produjo un brote de gripe, con más de la mitad (87/160 de los frotis de pacientes con síndrome gripal positivos para el virus (H1N1 2009 sin detectarse otros tipos de virus gripal. Coincidiendo con la onda de síndromes gripales observamos aumentos de consultas por síndrome febril e infección respiratoria de vías altas. En comparación con la media de los tres años anteriores, en el verano del 2009 se produjo un incremento del 44! en consultas por síndrome febril (de 3,6 a 5,3 por 1000: p<0,001, del 6! en consultas por infección de vías altas (de 13,2 a 14,1 por 1000; p<0,001 y del 8! en consultas por bronquitis aguda (de 6,3 a 6,9 por 1000; p=0,003. Estos diagnósticos supusieron 3,2 consultas adicionales por 1.000 habitantes atribuibles a la gripe, es decir, un 58! de consultas adicionales. Conclusiones: La gripe se acompaña de aumento en el número de consultas por síndrome febril y por infección respiratoria de vías altas.

Examenes pulmonares por el método de Abreu: sus resultados

Directory of Open Access Journals (Sweden)

Alfonso Reyes

1950-02-01

definitiva en 1936. Posteriormente el doctor Hanker aplica la Abrengrafía al examen en serio de colectividades. Entre nosotros, fue el doctor Omar Benavides en 1940 quien presentó su trabajo de tesis sobre las primeras abreugrafías tomadas en un aparato ideado por él. En Bogotá, se inició la campaña por este sistema en enero de 1947 con la fundación del Centro Epidemiológico No 1, dirigido por el doctor Antonio Acosta Pinzón.

Micetoma pulmonar por Scedosporium sp, reporte de dos casos

Directory of Open Access Journals (Sweden)

José G. Somocurcio

2009-07-01

Full Text Available Se reporta los dos primeros casos de micetoma pulmonar por Scedosporium sp, en el Perú, tratados quirúrgicamente en el Hospital Nacional Hipólito Unanue. Se practicó resección pulmonar debido a micetoma pulmonar de donde se tomó muestras que fueron enviadas a microbiología y anatomía patológica para cultivo y estudio histopatológico. Se identificó el moho Scedosporium sp en dos pacientes con secuelas cavitarias por tuberculosis, quienes presentaron tos y hemoptisis de dos meses y tres años de evolución, respectivamente. Radiológicamente las cavidades estaban ocupadas por una "bola fúngica". La histopatología indicó presencia de abundantes hifas, indistinguibles de las de Aspergillus sp, mientras que la inmunodifusión para Aspergillus fue negativa.

GRAVIDADE DE INTOXICAÇÕES POR SANEANTES CLANDESTINOS

Directory of Open Access Journals (Sweden)

Jessica Adrielle Teixeira Santos

2011-01-01

Full Text Available El presente estudio tuvo como objetivo analizar las intoxicaciones por saneantes comercializados clandestinamente, reportadas en el Centro de Control de Intoxicaciones del Hospital Universitario Regional de Maringá. Es un estudio cuantitativo, con análisis retrospectivo de registros epidemiológicos de personas intoxicadas por estos agentes, en el período de enero de 2005 a diciembre de 2009. De los 118 casos reportados, la mayoría (74-62,7% se produjeron en varones, 105 (88,9% necesitaron de asistencia en unidades de atención de emergencia y hospitalización de alta complejidad, en 14 casos (11,8% requirieron de Cuidados Intensivos, y se reportaron cinco óbitos, todos por intoxicación intencional. Los resultados demuestran la gravedad y la letalidad de este tipo de intoxicación, sugieren la necesidad de medidas urgentes de fiscalización y control de la Vigilancia Sanitaria, así como de medidas para la educación de los consumidores, haciendo hincapié en el papel educativo de la Enfermería

BACTERIAL LEACHING OF ELECTRONIC SCRAP: INFLUENCE OF PROCESS PARAMETERS

Directory of Open Access Journals (Sweden)

Luciana Harue Yamane

2013-03-01

Full Text Available The application of bacterial leaching in the ore treatment is already known and also can be applied such as treatment of electronic waste to copper recovery. This paper investigates the influence of process parameters (pulp density, inoculums volume, rotation speed and initial concentration of ferrous iron on bacterial leaching of copper from printed circuit board of computers using the bacterium Acidithiobacillus ferrooxidans–LR. Printed circuit boards from computers were comminuted using a hammer mill. The powder obtained was magnetically separated and the non-magnetic material used in this study. A shake flask study was carried out on the non-magnetic material using a shaker. The results show that Acidithiobacillus ferrooxidans–LR can leach 99% of copper from printed circuit boards (non–magnetic material under the determined conditions through of the studies.

Por uma estrada do M' Boi Mirim sustentável

Directory of Open Access Journals (Sweden)

Carlos Henrique Santos de Oliveira

2015-10-01

Full Text Available Este artigo trata de avaliar importante via de transporte situada na zona sul da cidade de São Paulo, analisando quais fatores dificultam a circulação de bens e pessoas no espaço urbano, bem como a dificuldade de promover a mobilidade urbana de acordo com os princípios de sustentabilidade, por meio de uma pesquisa qualitativa, exploratória e bibliográfica, com base em um estudo de caso realizado na Estrada do M’ Boi Mirim. Os instrumentos de coleta de dados utilizados foram a observação pessoal, bem como pesquisas em artigos científicos, dissertações e teses relacionadas ao tema. Apesar de essa questão estar sendo amplamente discutida por diversos setores da sociedade, notam-se poucas soluções práticas, haja vista, o crescente uso de transportes individuais motorizados, muitos acidentes nas vias e por muitas vezes, pouca infraestrutura, bem como a falta integração das regiões por meio das vias existentes, principalmente em áreas distantes do centro das cidades.

Algunos aspectos relacionados con las enfermedades tropicales transmitidas por moluscos

Directory of Open Access Journals (Sweden)

A. Mijail Pérez

1999-12-01

Full Text Available Muchas especies de moluscos son hospedantes de diversos parásitos que provocan infecciones muy serias e incluso mortales en seres humanos y ganado. La esquistosomiasis extendida por 74 países, infecta a unos 200 millones de personas y está en segundo lugar, después de la malaria, como causa de la mortalidad humana originada por parásitos. La infección es causada por un platelminto que se desarrolla en caracoles de agua dulce y que desde el agua puede penetrar en la piel de un ser humano y desarrollarse dentro de sus órganos, produciendo distintos grados de infección, hasta provocar la muerte. Distintas especies de esos caracoles están extendidas por Centro América. El cólera, otra enfermedad que también es mortal, se ha encontrado en moluscos bivalvos comestibles colectados en el Golfo de Nicoya, que bordea Nicaragua y Costa Rica Estas epidemias se pueden combatir con diversos métodos de control de los caracoles hospedantes de parásitos.

Fístula vesicovaginal por litíase: relato de caso

Directory of Open Access Journals (Sweden)

Chambô Filho Antônio

2003-01-01

Full Text Available As fístulas de etiologia traumática são raras, sobretudo as intrínsecas por litíase vesical. O manejo dessas fístulas tem controvérsias no que diz respeito à técnica cirúrgica ideal. Uma variedade de tratamentos tem sido descrita, incluindo reparação cirúrgica por vias transvaginal e transabdominal. Os autores relatam o caso de uma paciente com queixa de perda urinária contínua com evolução de seis meses, sendo identificado ao exame especular orifício fistuloso no terço médio da parede anterior da vagina, por onde se exteriorizava urina. Nesta topografia, identificava-se, durante o toque bimanual, estrutura de consistência pétrea. A suspeita de litíase vesical foi confirmada pela radiografia de pelve. O tratamento cirúrgico se deu em dois tempos, com exérese do cálculo vesical e posterior correção da fístula por via vaginal.

Agente topológico de aprendizado por reforço

OpenAIRE

Arthur Plínio de Souza Braga

2004-01-01

Os métodos de Aprendizagem por Reforço (AR) se mostram adequados para problemas de tomadas de decisões em diversos domínios por sua estrutura flexível e adaptável. Apesar de promissores, os métodos AR frequentemente tem seu campo de atuação prático restrito a problemas com espaço de estados de pequeno ou médio porte devido em muito à forma com que realizam a estimativa da função de avaliação. Nesta tese, uma nova abordagem de AR, denominada de Agente Topológico de Aprendizagem por Reforço (AT...

Detección de anticuerpos antiplasmodium por ELISA en donantes de sangre

Directory of Open Access Journals (Sweden)

Patricia Olaya de Morales

1982-06-01

Full Text Available La malaria, una enfermedad transmitida por mosquitos del genero anopheles, puede ser inducida a través de transfusiones de sangre infectada con alguna de las especies de Plasmodium que afectan al hombre. Con el objeto de determinar el riesgo potencial de infección inducida por transfusiones, se analizaron durante 9 meses y mediante la técnica de E.L.I.S.A., las muestras de suero tomadas a los donantes de sangre del Hospital Militar Central de Bogotá. El 8.6 por mil de las 3114 muestras analizadas, resultaron positivas para anticuerpos antimaláricos y durante el tiempo del estudio fueron detectados 3 casos de malaria inducida por transfusiones.

Dano cavitacional em revestimentos depositados por aspersão termica a chama

OpenAIRE

Paulo Villani Marques

1996-01-01

Resumo: Quantias elevadas são gastas anualmente na manutenção de turbinas hidráulicas usadas na geração de energia elétrica por causa do ataque cavitacional. Avaliou-se a aplicabilidade de revestimentos metálicos e cerâmicos depositados sobre aço carbono por aspersão térmica a chama na manutenção destes equipamentos em função de sua resistência à erosão por cavitação. Foram realizados ensaios de dureza, rugosidade, ensaio acelerado de cavitação induzida por vibração ultra-sônica, adesão (traç...

Nodulose por Metotrexato Methotrexate Induced Nodulosis

Directory of Open Access Journals (Sweden)

Fernanda Guidolin

2005-08-01

Full Text Available A nodulose por metotrexato (MTX é um dos efeitos colaterais pouco conhecidos do uso desse medicamento em doses baixas. Embora classicamente descrita em casos de artrite reumatóide, tem aparecido, também, em outras doenças reumáticas. Descreve-se aqui um caso de nodulose por MTX em uma paciente com artrite reumatóide soropositiva, que utilizava esse medicamento há um ano, com bom controle do processo articular. Segue-se uma breve revisão sobre o assunto.Methotrexate-induced nodulosis is a rare side effect of this drug when it is used in low doses. Although classically described in rheumatoid arthritis patients, it may also appear in other rheumatic disorders. We describe a seropositive rheumatoid arthritis patient who developed methotrexate-induced nodulosis after using this drug for a year, with good control of articular symptoms. This case presentation is followed by a brief revision on the subject.

Reacciones adversas por antiinflamatorios no esteroideos

Directory of Open Access Journals (Sweden)

Luisa Ivet Sánchez Ricardo

2011-03-01

Full Text Available Se realizó un estudio descriptivo y transversal en el Consultorio Médico de la Familia No. 28 perteneciente al Policlínico Universitario y Docente "Dr. Mario Muñoz Monroy" desde el 1ro. de junio al 31 de diciembre de 2008, con el objetivo de detectar las reacciones adversas más frecuentes provocadas por el consumo de antiinflamatorios no esteroideos. El universo estuvo constituido por 105 pacientes que asistieron a consulta en el tiempo de estudio y de estos se seleccionó una muestra de 60 pacientes, a quienes se les aplicó un cuestionario de preguntas donde se recogieron las variables de análisis. .Las mujeres resultaron las que más antiinflamatorios consumieron y en el rango de edades de 31-59 años. Las reacciones adversas que más se reportaron fueron la epigastralgia y la hipertensión arterial, así mismo se comprobó la automedicación en algunos pacientes.

Engorde de bagres (Rhamdia quelen) en sistema de cultivo intensivo por sexos separados

OpenAIRE

Comolli, J; Roux, J.P; Sánchez, S; Hernández, D

2013-01-01

El bagre sudamericano (ramdiá o jundiá) se caracteriza por rápido crecimiento en los primeros meses de vida e importante diferencia de desarrollo entre ambos sexos. La madurez sexual del macho es precoz, por lo cual la hembra alcanza un peso vivo 30% mayor que el del macho. El presente trabajo tuvo por objetivo analizar el engorde de especimenes de Rhamdia quelen separados por sexos en un sistema intensivo. Se llevaron a cabo tres tratamientos: TA- hembra, TB- mixto y TC- macho. El engorde se...

Coeficiente de fricción por curvatura no intencional en concreto postensado

Directory of Open Access Journals (Sweden)

Diego Ernesto Dueñas Puentes

2007-09-01

Full Text Available En el presente artículo se establece un coeficiente de fricción por curvatura no intencional (K para puentes de placa y vigas y puentes por voladizos sucesivos a partir de los registros de tensionamiento de algunos puentes postensados construidos en Colombia, el cual es inferior al empleado habitualmente en el diseño de puentes pos-tensados en el país y establecido por el Código Colombiano de Diseño Sísmico de Puentes (CCDSP publicado por el Instituto Nacional de Vías en 1995. Este estudio parte del hecho de que en algunas importantes obras se obtienen alargamientos de torones mayores a los estimados teóricamente, puentes de los cuales se dispone de registros de tensionamiento y de los que se deducen valores de coeficientes más cercanos a los indicados por las últimas ediciones de la Standard Specifications for Highway Bridges, publicada por American Association of State Highway and Transportation Officials “AASHTO”. En Colombia, el CCDSP, considera un coeficiente de fricción por curvatura no intencional (K para cables, con valores entre 0.0050 y 0.00066 m-1, dependiendo del material del que esté fabricado el ducto (acero galvanizado, sin galvanizar, metal brillante, valor superior al encontrado en este trabajo. En este artículo, en primer lugar, se realiza una breve descripción del efecto de fricción a lo largo de los cables, presentando los diferentes valores de coeficientes de fricción indicados en el CCDSP y en “AASHTO.”, en el diseño de puentes preesforzados. Se hace una corta descripción de cada uno de los puentes de los cuales se tienen registros de tensionamiento con el fin de identificar otras variables que intervienen en el proceso de ten-sionamiento como materiales, equipos y mano de obra, y posteriormente, a partir de la validación y tabulación de datos registrados en obra (registros en los cuales se controla la fuerza aplicada y el alargamiento de los torones, se efectuó la evaluación del coeficiente

Bloqueios nervosos guiados por ultra-som Bloqueos nerviosos guiados por ultrasonido Ultrasound-guided nerve blocks

Directory of Open Access Journals (Sweden)

Pablo Escovedo Helayel

2007-02-01

Full Text Available JUSTIFICATIVA E OBJETIVOS: As técnicas de bloqueios nervosos guiados por ultra-som são baseadas na visualização direta das estruturas nervosas, da agulha de bloqueio e das estruturas anatômicas adjacentes. Desta maneira, é possível depositar a solução de anestésico local precisamente em torno dos nervos e acompanhar a sua dispersão em tempo real, obtendo-se, assim, um bloqueio mais eficaz, de menor latência, menor dependência de referências anatômicas, menor volume de solução anestésica e maior segurança. CONTEÚDO: O artigo revisa os aspectos relativos aos mecanismos físicos para formação de imagens, a anatomia ultra-sonográfica do neuroeixo e dos plexos braquial e lombossacral, os equipamentos e materiais empregados nos bloqueios, os ajustes do aparelho de ultra-som para melhorar as imagens, os planos de visualização das agulhas de bloqueio e as técnicas e o treinamento em bloqueios guiados por ultra-som. CONCLUSÕES: Os passos para se obter sucesso em anestesia regional incluem a identificação exata da posição dos nervos, a localização precisa da agulha, sem lesões nas estruturas adjacentes e, finalmente, a injeção cuidadosa de anestésico local junto aos nervos. Embora a neuroestimulação forneça grande auxílio na identificação dos nervos, esta não consegue, isoladamente, preencher todas essas exigências. Por isso, acredita-se que os bloqueios guiados por ultra-som serão a técnica de eleição para anestesia regional num futuro não muito distante.JUSTIFICATIVA Y OBJETIVOS: Las técnicas de bloqueos nerviosos guiados por ultrasonido se basan en la visualización directa de las estructuras nerviosas, de la aguja de bloqueo y de las estructuras anatómicas adyacentes. De esa manera, se puede depositar la solución de anestésico local precisamente en torno de los nervios y acompañar su dispersión en tiempo real, obteniéndose así, un bloqueo más eficaz, de menor latencia, menor dependencia de

Sinterização ultrarrápida por micro-ondas de compósitos particulados PZT/FCO preparados por mistura em ultrassom

Directory of Open Access Journals (Sweden)

C. P. Fernandez

Full Text Available Resumo Pós de Pb(Zr0,53Ti0,47O3 (PZT e Fe2CoO4 (FCO, foram sintetizados separadamente pelo método Pechini e misturados em ultrassom, nas proporções molares 80/20 e 50/50 (PZT/FCO. Os compósitos preparados foram prensados e submetidos à sinterização em forno convencional e sinterização ultrarrápida assistida por micro-ondas. A caracterização estrutural e microestrutural das amostras foram realizadas por difração de raios X e microscopia eletrônica de varredura, respectivamente. Medidas de constante dielétrica em função da temperatura, resistividade elétrica e coeficiente de acoplamento magnetoelétrico foram também realizadas. Os resultados evidenciaram que o método de mistura do PZT com a FCO por ultrassom foi rápido e eficiente, gerando, após sinterização, compósitos particulados com conectividade global (0-3 e distribuição uniforme de grãos da fase ferromagnética (FCO na matriz ferroelétrica (PZT. Da análise estrutural, verificou-se que a sinterização por micro-ondas propiciou um arranjo diferenciado no esquema de conectividade local na amostra (1-3 e (2-3, relacionada com a intensificação dos processos de difusão que ocorrem nesse tipo de sinterização principalmente em sistemas nanométricos. Pelos altos valores de resistividade obtidos, comprovou-se que a integridade das fases foi conservada nos dois métodos de sinterização, sendo mais eficiente na sinterização por micro-ondas, característica que garantiu o comportamento magnetoelétrico em todos os compósitos estudados neste trabalho. Os valores do campo Hmax foram dependentes da concentração da fase ferrita e da sinterização; para a composição 80/20 de 1,4 e 1,9 kOe, e para 50/50 de 3,5 e 3,0 kOe nas amostras sinterizadas por micro-ondas e convencionalmente, compatíveis com a literatura e que confirmaram a integridade das fases constituintes PZT e FCO.

Variaciones regionales de la mortalidad por homicidios en Jalisco, México

Directory of Open Access Journals (Sweden)

Vega-López María Guadalupe

2003-01-01

Full Text Available El presente estudio busca describir las variaciones regionales de la mortalidad por homicidios en el estado de Jalisco, México, en 1989-1991, 1994-1996 y 1999-2000, analizando a su vez el comportamiento de la tasa de homicidios según género y estratos de bienestar socioeconómico. A partir de la información sobre mortalidad generada por el Instituto Nacional de Estadística, Geografía y Informática, se calcularon tasas ajustadas por edad y género e índices de sobremortalidad masculina. Además, se calcularon razones de tasa y su intervalo de confianza (95%. Los resultados reflejan que la tasa de homicidios presenta una tendencia decreciente en los años 90; que existe un patrón regional de la mortalidad por homicidios, observándose las tasas más altas en regiones periféricas del estado consideradas entre las más pobres; que los municipios ubicados en el estrato de bienestar más bajo presentan un exceso de mortalidad por homicidios estadísticamente significativo, y que hay una evidente sobremortalidad masculina por esta causa. Aspectos como los antes descritos implican tareas y desafíos para la salud pública y para los organismos encargados de preservar la ley y el orden, entre ellos la necesidad de implementar políticas intersectoriales diferenciadas, que tomen en consideración las particularidades que rodean al homicidio y al crimen violento en Jalisco.

Analisis cualitativo asistido por computadora Computer-assisted qualitative analysis

Directory of Open Access Journals (Sweden)

César A. Cisneros Puebla

2003-01-01

Full Text Available Los objetivos de este ensayo son: por un lado, presentar una aproximación a la experiencia hispanoamericana en el Análisis Cualitativo Asistido por Computadora (ACAC al agrupar mediante un ejercicio de sistematización los trabajos realizados por diversos colegas provenientes de disciplinas afines. Aunque hubiese querido ser exhaustivo y minucioso, como cualquier intento de sistematización de experiencias, en este ejercicio son notables las ausencias y las omisiones. Introducir algunas reflexiones teóricas en torno al papel del ACAC en el desarrollo de la investigación cualitativa a partir de esa sistematización y con particular énfasis en la producción del dato es, por otro lado, objetivo central de esta primera aproximación.The aims of this article are: on the one hand, to present an approximation to the Hispano-American experience on Computer-Assisted Qualitative Data Analysis (CAQDAS, grouping as a systematization exercise the works carried out by several colleagues from related disciplines. Although attempting to be exhaustive and thorough - as in any attempt at systematizing experiences - this exercise presents clear lacks and omissions. On the other hand, to introduce some theoretical reflections about the role played by CAQDAS in the development of qualitative investigation after that systematization, with a specific focus on data generation.

Meningitis por Streptococcus suis

OpenAIRE

Geffner Sclarsky, D. E.; Moreno Muñoz, R.; Campillo Alpera, Mª.S.; Pardo Serrano, F.J.; Gómez Gómez, A.; Martínez-Lozano, Mª.D.

2001-01-01

La infección humana por Streptococcus suis (S. suis) es una zoonosis, con un riesgo ocupacional conocido y que suele presentarse como meningitis purulenta, que tiene baja mortalidad y frecuentes secuelas de hipoacusia y ataxia. Se han publicado menos de 150 casos humanos desde el informe original de hace 30 años. Hay una reconocida distribución geográfica viviendo la mayoría de los afectados en el norte de Europa y el sudeste Asiático. En España se han comunicado dos pacientes con enfermedad ...

Apendicitis por Paracoccidioides brasiliensis.

OpenAIRE

MUÑOZ URRIBARRI, Ana Beatriz; CHAPARRO DAMMERT, Eduardo; FERRUFINO LLACH, Juan Carlos; VASQUEZ FLORES, Luciola

2012-01-01

La paracoccidioidomicosis es la micosis más prevalente en Sudamérica. La forma aguda afecta el sistema fagocítico mononuclear de niños y personas inmunocomprometidas. El compromiso gastrointestinal es frecuente y su patogenia implica diseminación hematógena y linfática. La linfadenomegalia abdominal causa obstrucción intestinal y abdomen agudo. En este artículo damos a conocer el caso de un niño con compromiso gastrointestinal por apendicitis. Este es el primer caso reportado de apendicitis p...

Modality differences between written and spoken story retelling in healthy older adults

Directory of Open Access Journals (Sweden)

Jessica Ann Obermeyer

2015-04-01

Methods: Ten native English speaking healthy elderly participants between the ages of 50 and 80 were recruited. Exclusionary criteria included neurological disease/injury, history of learning disability, uncorrected hearing or vision impairment, history of drug/alcohol abuse and presence of cognitive decline (based on Cognitive Linguistic Quick Test. Spoken and written discourse was analyzed for micro linguistic measures including total words, percent correct information units (CIUs; Nicholas & Brookshire, 1993 and percent complete utterances (CUs; Edmonds, et al. 2009. CIUs measure relevant and informative words while CUs focus at the sentence level and measure whether a relevant subject and verb and object (if appropriate are present. Results: Analysis was completed using Wilcoxon Rank Sum Test due to small sample size. Preliminary results revealed that healthy elderly people produced significantly more words in spoken retellings than written retellings (p=.000; however, this measure contrasted with %CIUs and %CUs with participants producing significantly higher %CIUs (p=.000 and %CUs (p=.000 in written story retellings than in spoken story retellings. Conclusion: These findings indicate that written retellings, while shorter, contained higher accuracy at both a word (CIU and sentence (CU level. This observation could be related to the ability to revise written text and therefore make it more concise, whereas the nature of speech results in more embellishment and “thinking out loud,” such as comments about the task, associated observations about the story, etc. We plan to run more participants and conduct a main concepts analysis (before conference time to gain more insight into modality differences and implications.

Developmental venous anomaly in the newborn brain

International Nuclear Information System (INIS)

Horsch, S.; Govaert, P.; Cowan, F.M.; Benders, M.J.N.L.; Groenendaal, F.; Vries, L.S. de; Lequin, M.H.; Saliou, G.

2014-01-01

Cerebral developmental venous anomaly (DVA) is considered a benign anatomical variant of parenchymal venous drainage; it is the most common vascular malformation seen in the adult brain. Despite its assumed congenital origin, little is known about DVA in the neonatal brain. We report here the first cohort study of 14 neonates with DVA. Fourteen infants (seven preterm) with DVA diagnosed neonatally using cranial ultrasound (cUS) and magnetic resonance imaging (MRI) from three tertiary neonatal units over 14 years are reviewed. DVA was first detected on cUS in 6 and on MRI in 8 of the 14 infants. The cUS appearances of DVA showed a focal fairly uniform area of increased echogenicity, often (86 %) adjacent to the lateral ventricle and located in the frontal lobe (58 %). Blood flow in the dilated collector vein detected by Doppler ultrasound (US) varied between cases (venous flow pattern in ten and arterialized in four). The appearance on conventional MRI was similar to findings in adults. Serial imaging showed a fairly constant appearance to the DVAs in some cases while others varied considerably regarding anatomical extent and flow velocity. This case series underlines that a neonatal diagnosis of DVA is possible with carefully performed cUS and MRI and that DVA tends to be an incidental finding with a diverse spectrum of imaging appearances. Serial imaging suggests that some DVAs undergo dynamic changes during the neonatal period and early infancy; this may contribute to why diagnosis is rare at this age. (orig.)

Developmental venous anomaly in the newborn brain

Energy Technology Data Exchange (ETDEWEB)

Horsch, S. [Erasmus MC-Sophia Children' s Hospital, Department of Neonatology, Rotterdam (Netherlands); Helios Klinikum Berlin-Buch, Department of Neonatology, Berlin (Germany); Govaert, P. [Erasmus MC-Sophia Children' s Hospital, Department of Neonatology, Rotterdam (Netherlands); Cowan, F.M. [Hammersmith Hospital, Department of Paediatrics, Imperial College Healthcare NHS Trust, London (United Kingdom); Benders, M.J.N.L.; Groenendaal, F.; Vries, L.S. de [University Medical Centre Utrecht, Wilhelmina Children' s Hospital, Department of Neonatology, Utrecht (Netherlands); Lequin, M.H. [Erasmus MC/Sophia Children' s Hospital, Department of Paediatric Radiology, Rotterdam (Netherlands); Saliou, G. [University Hospital, Department of Neuroradiology, Le Kremlin-Bicetre (France)

2014-07-15

Cerebral developmental venous anomaly (DVA) is considered a benign anatomical variant of parenchymal venous drainage; it is the most common vascular malformation seen in the adult brain. Despite its assumed congenital origin, little is known about DVA in the neonatal brain. We report here the first cohort study of 14 neonates with DVA. Fourteen infants (seven preterm) with DVA diagnosed neonatally using cranial ultrasound (cUS) and magnetic resonance imaging (MRI) from three tertiary neonatal units over 14 years are reviewed. DVA was first detected on cUS in 6 and on MRI in 8 of the 14 infants. The cUS appearances of DVA showed a focal fairly uniform area of increased echogenicity, often (86 %) adjacent to the lateral ventricle and located in the frontal lobe (58 %). Blood flow in the dilated collector vein detected by Doppler ultrasound (US) varied between cases (venous flow pattern in ten and arterialized in four). The appearance on conventional MRI was similar to findings in adults. Serial imaging showed a fairly constant appearance to the DVAs in some cases while others varied considerably regarding anatomical extent and flow velocity. This case series underlines that a neonatal diagnosis of DVA is possible with carefully performed cUS and MRI and that DVA tends to be an incidental finding with a diverse spectrum of imaging appearances. Serial imaging suggests that some DVAs undergo dynamic changes during the neonatal period and early infancy; this may contribute to why diagnosis is rare at this age. (orig.)

Chronic unpredictable stress deteriorates the chemopreventive efficacy of pomegranate through oxidative stress pathway.

Science.gov (United States)

Hasan, Shirin; Suhail, Nida; Bilal, Nayeem; Ashraf, Ghulam Md; Zaidi, Syed Kashif; AlNohair, Sultan; Banu, Naheed

2016-05-01

Chronic unpredictable stress (CUS) can influence the risk and progression of cancer through increased oxidative stress. Pomegranate is known to protect carcinogenesis through its anti-oxidative properties. This study is carried out to examine whether CUS affects the chemopreventive potential of pomegranate through oxidative stress pathway. Role of CUS on early stages of 7, 12 dimethyl benz(a) anthracene (DMBA) induced carcinogenesis, and its pre-exposure effect on chemopreventive efficacy of pomegranate juice (PJ) was examined in terms of in vivo antioxidant and biochemical parameters in Swiss albino rats. Rats were divided in various groups and were subjected to CUS paradigm, DMBA administration (65 mg/kg body weight, single dose), and PJ treatment. Exposure to stress (alone) and DMBA (alone) led to increased oxidative stress by significantly decreasing the antioxidant enzymes activities and altering the glutathione (GSH), malondialdehyde (MDA), glutamate oxaloacetate transaminase (GOT), and glutamate pyruvate transaminase (GPT) levels. A significant increase in DNA damage demonstrated by comet assay was seen in the liver cells. Stress exposure to DMBA-treated rats further increased the oxidative stress and disturbed the biochemical parameters as compared to DMBA (alone)-treated rats. Chemoprevention with PJ in DMBA (alone)-treated rats restored the altered parameters. However, in the pre-stress DMBA-treated rats, the overall antioxidant potential of PJ was significantly diminished. Our results indicate that chronic stress not only increases the severity of carcinogenesis but also diminishes the anti-oxidative efficacy of PJ. In a broader perspective, special emphasis should be given to stress management and healthy diet during cancer chemoprevention.

Evaluación docente y aprendizaje por competencia de los estudiantes

OpenAIRE

Segovia Suller, Cirilo

2016-01-01

Métodos Estadísticos para la Investigación es una asignatura que genera un grado de dificultad en la enseñanza del docente y el aprendizaje del alumno. En el aula se investigó si existe una relación entre la evaluación docente y el aprendizaje por competencias de los estudiantes. El objetivo era determinar la relación entre la evaluación docente y el aprendizaje por competencias de los estudiantes, para luego formular la hipótesis: la evaluación docente se relaciona con el aprendizaje por com...

Fiebre Tifoidea Diagnóstico por pruebas inmunoenzimáticas: Elisa

Directory of Open Access Journals (Sweden)

Miguel Guzmán

1981-06-01

Full Text Available Este trabajo describe el desarrollo y normalización de una técnica inmunoenzimática para el diagnóstico indirecto de la Fiebre Tifoidea. El método permite un análisis simple y objetivo de los resultados. La reacción enzimática es proporcional a la concentración de anticuerpos en el suero contra el antígeno somático-0, por tanto, el método es cuantitativo. Por lo demás, la técnica tiene un alto grado de especificidad para Salmonella typhi, ya que los sueros de pacientes con Salmonelosis causada por Salmonella enteritidis serotipos paratyphi A, B y typhimurium dieron resultados negativos, en forma similar a los presentados por el grupo control antes de la vacunación específica. Los resultados obtenidos con esta técnica permitieron definir el nivel de anticuerpos que puede presentar una población control supuestamente sana frente a los niveles inducidos por la enfermedad. Los resultados postvacunales en el grupo control mostraron títulos sorprendentemente bajos; un análisis de este fenómeno se presentó en forma amplia. Igualmente se proponen futuras investigaciones sobre este campo.

HOSPITALIZACIONES EVITABLES POR INSUFICIENCIA CARDÍACA. VARIABLES RELACIONADAS

Directory of Open Access Journals (Sweden)

Victoria Ruiz-Romero

2016-01-01

Full Text Available Los ingresos hospitalarios evitables por insuficiencia cardiaca (IC son un problema para los sistemas de salud, consumen recursos, generan morbilidades adicionales y alta mortalidad. El objetivo del estudio fue conocer los factores de riesgo de las personas hospitalizadas por insuficiencia cardiaca. Métodos: Se constituyó un grupo con médicos de atención primaria y hospitalaria. Se realizaron auditorías de las historias clínicas de 110 pacien - tes de la poblacion de la comarca del Aljarafe con mayores tasas de ingreso por insuficiencia cardiaca y estudio descriptivo y comparativo con T-Student y U-Mann Whitney para cuantitativas y λ 2 y Fisher para cualitativas. Resultados: Los pacientes que ingresaron por IC tenían 78,1 años (SD: 9,56 de media; 73 (66,4% fueron mujeres; un Índice Barthel de 45,0 de media; un 53,5% con grado III de la NYHA y 17 (15,5% institucionaliza - dos. El 70% presentaban 3-5 comorbilidades, hipertensión (87,3%, dislipe - mia (60,0% diabetes (57,3%, enfermedad renal crónica (56,4%, anemia (53,2% o fibrilación auricular (52,7%. Fallecieron al ingreso 23 (20,9% pacientes. Conclusiones: Los ingresos se dieron en personas mayores con múl - tiples enfermedades (hipertensión, diabetes, EPOC, enfermedad renal y escasa capacidad para actividades básicas de la vida diaria. El fallecimiento hospitalario se asoció a edad avanzada, ser mujer, menor uso de betabloqueantes y la no inclusión del paciente en el proceso asistencial.

161. Necrosis por presión del septo de salida ventricular causado por dos implantes adyacentes

Directory of Open Access Journals (Sweden)

A. González Calle

2012-04-01

Conclusiones: Esta complicación ilustra que los tejidos entre dos dispositivos duros y con movimiento uno conrespecto al otro pueden desarrollar necrosis por presión y fricción y, consecuentemente, perforación. Probablemente, hubiera sido preferible sustituir el homoinjerto pulmonar con stent en el momento de la sustitución valvular aórtica.

Uso de contraceptivos por puérperas adolescentes

Directory of Open Access Journals (Sweden)

Fernanda Schulz da Rosa

2014-07-01

Full Text Available Objetivo: Indagar el uso de métodos contraceptivos por las puérperas adolescentes a fin de relacionar su (desuso con el embarazo en la adolescencia. Método: Estudio transversal, descriptivo, realizado por medio de un instrumento estructurado con 181 puérperas adolescentes que tuvieron sus partos en el hospital participante de la investigación. Los datos fueron recolectados en el período de diciembre de 2008 a diciembre de 2009. Resultados: El 64,1% de las puérperas usaba algún método contraceptivo antes del embarazo; los métodos más utilizados fueron el anticoncepcional oral (51% y el preservativo masculino (29%. Para el 75% de las adolescentes el embarazo fue planeado y justificado por el deseo y la voluntad propia de experimentar la maternidad. Conclusión: Considerando que casi la mitad de las adolescentes entrevistadas deseaba el embarazo, se deduce que investigar y discutir apenas el uso o no de los métodos contraceptivos no es adecuado. Es necesario profundizar las investigaciones acerca de los significados de ser madre en la adolescencia.

Extracción de sustancias asistida por ultrasonido (EUA

Directory of Open Access Journals (Sweden)

Rocío Azuola

2007-11-01

Full Text Available Compuestos presentes en los vegetales con propiedades funcionales o tecnológicas, han cobrado gran importancia en los mercados de alimentos, farmacéuticos y cosméticos. Se buscan métodos eficientes, económicos y favorables al ambiente para la extracción de estas sustancias. Se ha realizado un estudio bibliográfico de las publicaciones recientes sobre diferentes métodos de extracción y su comparación a las extracciones asistidas por ultrasonido (EAU con el fin de evaluar su eficacia y viabilidad industrial. Se ha encontrado que la EAU es más eficiente que los métodos de extracción tradicionales, y más económica y sencilla que los métodos de extracción no tradicionales como la extracción asistida por microondas, por lo cual se comprueba su viabilidad industrial.

Mortalidad por accidentes de tránsito en Bayamo, Cuba 2011

Directory of Open Access Journals (Sweden)

Arlines Piña-Tornés

Full Text Available Con el objetivo de describir la mortalidad por accidentes de tránsito en Bayamo, Cuba, en el año 2011 se realizó una revisión de los pacientes lesionados y fallecidos a causa de accidentes de tránsito, registrados en Hospital Carlos M. de Céspedes. Se atendieron en emergencias 1365 lesionados, predominando el grupo etario de 25 a 44 años con 372 pacientes (27,3%, y el sexo masculino con 1071 (78,5%. Fallecieron 46 personas, en su mayoría del mismo grupo de edad y de sexo masculino. Los traumatismos múltiples (52,6% y cráneofaciales (34,2% fueron las localizaciones predominantes. Se destacaron los atropellos por vehículo de motor con mortalidad del 26,3%. En conclusión, la mortalidad por accidentes de tránsito predomina en adultos jóvenes masculinos; cuyas consecuencias fatales son debido a traumatismos múltiples por atropellos.

Redes neuronales artificiales para la predicción de la calidad en soldadura por resistencia por puntos

Directory of Open Access Journals (Sweden)

Martín, O.

2006-10-01

Full Text Available An artificial neural network is proposed as a tool for predicting from three parameters (weld time, current intensity and electrode sort if the quality of a resistance spot weld reaches a certain level or not. The quality is determined by cross tension testing. The fact of reaching this quality level or not is the desired output that goes with each input of the artificial neural network during its supervised learning. The available data set is made up of input/desired output pairs and is split randomly into a training subset (to update synaptic weight values and a validation subset (to avoid overfitting phenomenon by means of cross validation.

Se propone una red neuronal artificial como herramienta para predecir, a partir de tres parámetros operativos (tiempo de soldadura, intensidad de corriente y tipo de electrodo, si la calidad de una unión soldada por resistencia por puntos alcanza o no un cierto nivel. El entrenamiento de la red neuronal conlleva que la calidad se determine previamente mediante ensayos de tracción en probetas en cruz. El hecho de alcanzar o no el citado nivel de calidad constituye la respuesta objetivo que acompaña a cada entrada de la red neuronal artificial durante su aprendizaje supervisado. El conjunto de datos disponible está formado por pares entrada/salida objetivo y se divide de forma aleatoria en un subconjunto de entrenamiento (para actualizar los valores de los pesos sinápticos y en un subconjunto de validación (para combatir el fenómeno de overfitting mediante validación cruzada.

Valor educativo y generalización del grupo "Alas por la vida" Educational value and generalization of "Alas por la Vida"

Directory of Open Access Journals (Sweden)

Alexis Hugo Cantero Ronquillo

2012-03-01

Full Text Available En el tratamiento del cáncer de mama, además de la agresión quirúrgica, en ocasiones mutilante, seguida o precedida por las molestias inherentes a los tratamientos oncoespecíficos, a veces persisten "heridas", que aunque invisibles, no siempre cierran totalmente, y afectan durante mucho tiempo, o toda la vida, a un grupo importante de pacientes y familiares cercanos. El proyecto "Alas por la vida" propone nuevas alternativas en el tratamiento de la mujer con cáncer de mama, que puedan prepararla para una nueva etapa, y vivir con el estatus de enferma crónica, que no refleje invalidez en el desempeño de sus funciones, que alcance la recuperación de su equilibrio biopsicosocial, y, consecuentemente, el disfrute de una adecuada calidad de vida. Mediante intercambios entre sobrevivientes de la enfermedad, familiares y profesionales, charlas científicas, sesiones de preguntas y respuestas, reflexiones de operadas en su lucha contra el cáncer de mama y también de sus esposos, así como con actividades socioculturales, etc., se han logrado resultados muy positivos por este grupo, lo que se refleja en encuestas realizadas a tal efecto. El Grupo de Apoyo a Pacientes Mastectomizadas "Alas por la vida", ha resultado ser un instrumento muy útil para elevar la autoestima y mejorar la calidad de vida de las sobrevivientes, que a la vez ha fortalecido y humanizado nuestra lucha contra el cáncer de mama, y se han aglutinando crecientemente más seguidores en esta noble causa, por lo que recomendamos se organicen proyectos similares en todas las provincias del país.In the treatment of beast cancer besides the surgical aggression occasionally mutilating followed or precedes by the molecules inherent to specific oncologic treatments, sometimes the "wounds" persist that although invisibles, not always are totally closed involving for much time or for life to a significant group of patients and close relatives.The project "Alas por la Vida" proposes

Distribuição espacial da violência: mortalidade por causas externas em Salvador (Bahia, Brasil

Directory of Open Access Journals (Sweden)

Paim Jairnilson Silva

1999-01-01

Full Text Available O presente estudo teve como objetivo descrever a distribuição da mortalidade por causas externas no espaço urbano de Salvador, Estado da Bahia, Brasil, em 1991. Foram calculados indicadores de mortalidade por causas externas e por tipos específicos de violência. A mortalidade proporcional por causas externas foi de 15% e a taxa de mortalidade correspondeu a 78,0 óbitos por 100 000 habitantes. As taxas de mortalidade por homicídios e por acidentes de transporte foram de 32,2 e 21,8 por 100 000 habitantes, respectivamente. Os idosos apresentaram um maior risco de morte por causas externas, seguidos dos adultos jovens e adolescentes. No caso dos idosos, 38% das mortes foram por acidentes de transporte e 28%, por quedas. Em relação aos jovens, predominam os homicídios, especialmente no sexo masculino e na faixa etária de 15 a 29 anos. Constatou-se uma distribuição desigual da mortalidade por causas externas no espaço urbano, penalizando, especialmente no caso dos homicídios, as populações residentes em bairros pobres, com taxas superiores ao coeficiente médio de Salvador. É necessário desenvolver medidas de prevenção e controle, incluindo políticas públicas e ações programáticas de saúde, orientadas para o espaço social sujeito a maior risco de morte por causas externas.

Mastitis bovina causada por Staphylococcus coagulasa negativos

OpenAIRE

Bonetto, César C.

2014-01-01

El presente Trabajo de Tesis se desprende como una línea de investigación del grupo de la UNRC dedicado al estudio de la problemática de la mastitis bovina tanto en aspectos básicos como aplicados con estudios genéticos, epidemiológicos y de virulencia de los principales microorganismos involucrados en la mastitis bovina. Staphylococccus coagulasa negativo (SCN) es un grupo bacteriano formado por varias especies que por lo general eran considerados flora oportunista de la piel y age...

La curiosidad por la naturaleza

Directory of Open Access Journals (Sweden)

José Vicente Rodríguez

2016-07-01

Full Text Available Esta actitud es un instrumento estratégico para estimular procesos de desarrollo realmente sostenibles, donde se aproveche la admiración que nos embarga al conocer y apreciar lo que nos rodea para responsablemente utilizar y conservar nuestros recursos naturales. Con esta reflexión deseo resaltar esa motivación de escudriñar lo desconocido, que fue también la virtud que propició el desarrollo de la personalidad de Francisco José de Caldas y Tenorio, uno de nuestros primeros y connotados sabios colombianos, y en cuyo honor se constituyó la revista de divulgación científica más importante del país, que en estos momentos cumple 76 años de existencia. Caldas tuvo curiosidad por todo lo que existía en su entorno; inicialmente en su natal Popayán, donde se maravilló por lo natural, lo que lo motivó y llevó más allá de su tierra a formar parte de la mayor empresa de exploración científica adelantada en ese entonces en territorio americano: la primera Expedición Botánica al nuevo Reino de Granada, de José Celestino Mutis.

Determinação do volume mínimo efetivo de bupivacaína 0,5% para bloqueio do plexo braquial por via axilar guiado por ultrassom

Directory of Open Access Journals (Sweden)

Leonardo Henrique Cunha Ferraro

2014-01-01

Full Text Available Justificativa e objetivo: o uso do ultrassom para acompanhar o correto posicionamento da agulha e a dispersão do anestésico local permitiu a redução do volume de anestésico local necessário para o bloqueio de nervos periféricos. Existem poucos trabalhos sobre o volume mínimo efetivo de anestésico local para o bloqueio do plexo braquial via axilar (BPVA. Este estudo foi conduzido com o objetivo de determinar o volume mínimo efetivo (VE90 de bupivacaína 0,5% comadrenalina (1:200.000 para o BPVA guiado por ultrassom. Método: o método up-and-down proposto por Massey e Dixon foi usado para o cálculo do volume mínimo efetivo. A dose inicial foi de 5 ml por nervo (radial, mediano, ulnar e musculocutâneo. No caso de falha do bloqueio, o volume era aumentado em 0,5 mL por nervo. O sucesso do bloqueio resultava na diminuição do volume em 0,5 mL por nervo para o paciente subsequente. O sucesso do bloqueio foi definido como bloqueio da função motora ≤ 2 segundo a escala de Bromage modificada, ausência de sensibilidade térmica e de resposta ao pinprick. Foi definido como critério para término do estudo a obtenção de cinco casos de falha seguidos de casos de sucesso. Resultados: foram incluídos 19 pacientes no estudo. O volume mínimo efetivo (VE90 de bupi-vacaína 0,5% com 1:200.000 de adrenalina foi de 1,56 ml (IC 95% 0,99-3,5 por nervo. Conclusão: este trabalho corrobora alguns estudos que mostram que é possível obter anestesia cirúrgica com baixos volumes de anestésico local para bloqueios de nervo periférico guiados por ultrassom.

Supplementation of inorganic phosphate enhancing the removal efficiency of tannery sludge-borne Cr through bioleaching.

Science.gov (United States)

Zheng, Guanyu; Zhou, Lixiang

2011-10-15

Four inorganic mineral nutrients including NH4+, K+, Mg2+ and soluble inorganic phosphate (Pi) were investigated to reveal the potential limiting nutrients for tannery sludge bioleaching process driven by Acidithiobacillus species, and the feasibility of supplementing the limiting nutrients to accelerate tannery sludge bioleaching was studied in the present study. It was found that the concentration of Pi was lower than 3.5 mg/L throughout the whole bioleaching process, which is the most probable restricting nutrient for tannery sludge bioleaching. Further experiments revealed that the deficiency of Pi could seriously influence the growth of Acidithiobacillus thiooxidans and lower its oxidization capacity for S0, and the limiting concentration of Pi for the growth of A. thiooxidans was 6 mg/L. The low concentration of soluble Pi in sludge matrix was resulted from the extremely strong sorbing/binding capacity of tannery sludge for phosphate. The supplementation of more than 1.6 g/L KH2PO4 into tannery sludge bioleaching system could effectively stimulate the growth of Acidithiobacillus species, enhance Cr removal rate and further shorten tannery sludge bioleaching period from 10 days to 7 days. Therefore, inorganic phosphate supplementation is an effective and feasible method to accelerate tannery sludge bioleaching process, and the optimum dosage of KH2PO4 was 1.6 g/L for tannery sludge with 5.1% of total solids. Copyright © 2011 Elsevier Ltd. All rights reserved.

Influences of extracellular polymeric substances on the dewaterability of sewage sludge during bioleaching.

Science.gov (United States)

Zhou, Jun; Zheng, Guanyu; Zhang, Xueying; Zhou, Lixiang

2014-01-01

Extracellular polymeric substances (EPS) play important roles in regulating the dewaterability of sludge. This study sought to elucidate the influence of EPS on the dewaterability of sludge during bioleaching process. Results showed that, in bioleaching system with the co-inoculation of Acidithiobacillus thiooxidans TS6 and Acidithiobacillus ferrooxidans LX5 (A. t+A. f system), the capillary suction time (CST) of sludge reduced from 255.9 s to 25.45 s within 48 h, which was obviously better than the controls. The correlation analysis between sludge CST and sludge EPS revealed that the sludge EPS significantly impacted the dewaterability of sludge. Sludge CST had correlation with protein content in slime and both protein and polysaccharide contents in TB-EPS and Slime+LB+TB layers, and the decrease of protein content in slime and decreases of both protein and polysaccharide contents in TB-EPS and Slime+LB+TB layers improved sludge dewaterability during sludge bioleaching process. Moreover, the low sludge pH (2.92) and the increasing distribution of Fe in the solid phase were another two factors responsible for the improvement of sludge dewaterability during bioleaching. This study suggested that during sludge bioleaching the growth of Acidithiobacillus species resulted in the decrease of sludge pH, the increasing distribution of Fe in the solid phase, and the decrease of EPS content (mainly including protein and/or polysaccharide) in the slime, TB-EPS, and Slime+LB+TB layers, all of which are helpful for sludge dewaterability enhancement.

Producción de energía por combustión de basuras en bogotá

OpenAIRE

Morales Gilede, Abel

2010-01-01

Este estudio tiene por objeto hacer un avalúo de la posibilidad de producir energía por medio de la incineración de las basuras provenientes de la ciudad de Bogotá. El estudio se desarrolló con base en la información existente. Elaborada especialmente por EDIS. Por contratos realizados por esta entidad con diferentes compañías y con la colaboración del Instituto de Investigaciones Tecnológicas y complementada por los Laboratorios de la Universidad Nacional. Con base en estos estudios se obtuv...

A INFLUÊNCIA DO AMBIENTE DE VAREJO NAS COMPRAS POR IMPULSO EM AEROPORTOS

Directory of Open Access Journals (Sweden)

Jorge Brantes Ferreira

2015-10-01

Full Text Available O fluxo de passageiros em aeroportos comerciais internacionais cresce a cada ano. Mais passageiros representam mais consumidores em fluxo e mais negócios. As condições particulares dos aeroportos criam experiências de varejo únicas, com evidências de comportamento de compra por impulso. Este estudo avalia a importância do ambiente de varejo e das emoções no comportamento de compra por impulso de consumidores em aeroportos aplicando uma versão do modelo de Mohan et al. (2013. Os dados foram coletados por meio de uma survey envolvendo 218 clientes do duty free shop de um grande aeroporto brasileiro e analisados por equações estruturais. Os resultados indicam que o ambiente de compras exerce grande influência sobre as emoções do consumidor e que estas têm forte influência sobre sua vontade de comprar por impulso.

EL MODELO LIBERAL COMO UN MODELO DEPREDADOR POR NATURALEZA

Directory of Open Access Journals (Sweden)

Julián Sabogal Tamayo

2003-07-01

Full Text Available Tuve la oportunidad de participar, por gentil invitación de la profesora Gertrudis Quijano, en el Diplomado de Geografía, lo cual me permitió acercarme un poco a quines estudian esta disciplina y me animó luego a participar en este Congreso, sobre una temática aparentemente lejana de mi formación de Economista. Mi contribución en esta conferencia se encamina al área del Medio Ambiente, que es uno de los componentes del Congreso que nos convoca. Espero hacerme entender y que mis reflexiones sean de alguna utilidad para ustedes, no necesariamente que estén de acuerdo conmigo, sino que mis planteamientos merezcan su atención y se puedan convertir para ustedes en objeto de discusión y ser involucrados en sus actividades académicas particulares. Creo que es necesario que los profesionales de las ciencias sociales, incluida la Geografía, vuelvan a pensar en los temas trascendentes y reversar la tendencia de los últimos lustros que invita solamente a preocuparse por temas llamados prácticos, por el día a día. Yo suelo preguntarles a mis estudiantes, cuando me expresan sus deseos de adquirir saberes prácticos, que les permitan ganarse la vida, y..., ¿quién pensará por ustedes? Recordemos al gran Oscar Wilde quien afirmaba que el medio seguro de no saber nada de la vida es intentar hacerse útil.

Fatal pneumonia by Legionella in a farmer with hypersensitivity pneumonitis Neumonía por Legionella con desenlace fatal en un granjero con neumonitis por hipersensibilidad

Directory of Open Access Journals (Sweden)

Vega García López

2009-12-01

Full Text Available Background: The retrospective investigation of a fatal sporadic Legionnaires' disease identified an unknown case of occupational hypersensitivity pneumonitis in a swine breeder. Methods: Chest high-resolution computed tomography, bronchoalveolar lavage, lung biopsy, arterial gasometry, pulmonary function tests and autopsy were performed. It was studied the presence of Legionella by serology and risk water samples were analyzed to identify the Legionella's source. Results: HP and Legionella pneumophila pneumonia diagnostics were confirmed. Lung fibrosis, a restrictive functional pattern, decreased diffusion, hypoxemia and bronchoalveolar lavage lymphocytosis were evidenced. Legionella´s source was detected in a shower and a positive serology in the patient. Autopsy verified pulmonary fibrosis and the septic shock leaded to Legionella causing the death. Conclusions: Chronic cough and pulmonary infiltrates in a farmer should suspect the presence of hypersensitivity pneumonitis. Later diagnosis carries a worse prognosis, the offending antigens exposure can't be avoided and fibrotic stage enhanced opportunity infection disease.Introducción: La investigación retrospectiva sobre un fallecimiento aislado por Legionelosis, hizo aflorar un caso de neumonitis por hipersensibilidad en un granjero cuidador de cerdos. Métodos: Se realizaron las siguientes pruebas: tomografía axial computerizada de alta resolución, lavado broncoalveolar, biopsia pulmonar, gasometría arterial, pruebas de función respiratoria y autopsia. Se estudió la presencia de Legionella por serología y se analizaron las muestras de fuentes de riesgo para identificar el foco de Legionella. Resultados: El estudio confirmó los diagnósticos de neumonitis por hipersensibilidad y neumonía por Legionella pneumophila. Las pruebas realizadas objetivaron la fibrosis pulmonar, un patrón respiratorio funcional restrictivo, un descenso de la difusión pulmonar, hipoxemia y la presencia de

Influence Of Used Bacterial Culture On Zinc And Aluminium Bioleaching From Printed Circuit Boards

Directory of Open Access Journals (Sweden)

Mrazikova Anna

2015-06-01

Full Text Available Bioleaching processes were used to solubilize metals (Cu, Ni, Zn and Al from printed circuit boards (PCBs. In this study, a PCBs-adapted pure culture of Acidithiobacillus ferrooxidans, pure culture of Acidithiobacillus thiooxidans and PCBs-adapted mixed culture of A. ferrooxidans and A. thiooxidans were used for recovery of the metals. The study showed that the mixed bacterial culture has the greatest potential to dissolve metals. The maximum metal bioleaching efficiencies were found to be 100, 92, 89 and 20% of Cu, Ni, Zn and Al, respectively. The mixed culture revealed higher bacterial stability. The main factor responsible for high metal recovery was the ability of the mixed culture to maintain the low pH during the whole process. The pure culture of A. thiooxidans had no significant effect on metal bioleaching from PCBs.

[Evaluation of leptin levels in plasma and their reliance on other hormonal factors affecting tissue fat levels in people with various levels of endogenous cotisol].

Science.gov (United States)

Robaczyk, Maciej G

2002-01-01

The discovery of leptin (LEP) shed new light on mechanisms regulating body fat mass (BFM). In this aspect, interactions between LEP and glucocorticoids at hypothalamic level may be of great importance. Factors that influence plasma LEP levels have not been fully recognized and available data on LEP levels are often inconsistent. The aim of this study was to evaluate absolute and BFM-corrected plasma LEP levels and their diurnal variation, as well as to assess the relationship between LEP levels, body fat distribution, and hormones influencing body fat in subjects with various levels of endogenous cortisol and different nutritional status. Group I was composed of 14 women aged 14-58 yrs, BMI of 23.9-37.1 kg/m2, with hypercortisolism due to ACTH-dependent and ACTH-independent Cushing's syndrome (CUS). 17 women with visceral obesity (OTY) and normal or disturbed carbohydrate metabolism, i.e. impaired glucose tolerance (IGT) and diabetes mellitus (DM), aged 24 do 50 yrs, BMI 30.0-46.1 kg/m2, were included in group II. Group III consisted of 14 women with Addison's disease (AD), aged 18 do 63 yrs, BMI 15.4-31.6 kg/m2. The control group IV (KON) included 17 healthy women with normal BMI. BMI, WHR, body composition, and body fat distribution (DEXA method) were assessed in all subjects. Basal plasma levels of LEP, beta-endorphin (B-EP), cortisol (F), insulin-like growth factor-1 (IGF-1) were measured with RIA test kits. Plasma adrenocorticotrophin (ACTH) levels, serum levels of insulin (IRI) and growth hormone (GH) were measured with IRMA test kits. Blood glucose (G) concentration was determined with an enzymatic method. Adiposity-corrected LEP levels were expressed as LEP/BFM and LEP/%BF indices. Fasting insulin resistance index (FIRI) was also calculated. Higher BFM and %BF values were found in the OTY group as compared with CUS KON and AD groups. BFM distribution did not differ in KON and AD groups whereas CUS subjects exhibited a higher accumulation of fat in the trunk

Riesgos antrópicos generados por la actividad minera

OpenAIRE

Ana Violeta Argüello Mejía; Enriqueta Cantos Aguirre; Jorge Vitery Moya

2013-01-01

Las actividades productivas generan riesgos antrópicos [1] a mediano y largo plazo. La zona de estudio se ubica en las Parroquias de Pomasqui, San Antonio y Calacalí, donde se han producido riesgos debido a las actividades humanas, en este caso, por la explotación de las canteras para abastecer el mercado de la construcción del Distrito Metropolitano de Quito. La investigación propone determinar los riesgos antrópicos generados por la actividad minera. Los pobladores de la zona identifican qu...

Responsabilidad civil por accidentes en espectáculos taurinos

OpenAIRE

Caballero Moreno, María Araceli

2016-01-01

El trabajo versa sobre la responsabilidad civil aplicada al campo de los espectáculos taurinos, explicando el régimen de responsabilidad aplicable, regulado en el art. 1.902 de nuestro Código Civil, centrándose especialmente en quién debe asumir la responsabilidad en caso de producirse daños a los espectadores del festejo por los propios animales, si la propia víctima por haber llevado a cabo una conducta imprudente aplicando la teoría de la asunción del riesgo o los organizadores del festejo...

Invalidez por dor nas costas entre segurados da Previdência Social do Brasil

Directory of Open Access Journals (Sweden)

Ney Meziat Filho

2011-06-01

Full Text Available OBJETIVO: Descrever as aposentadorias por invalidez decorrente de dor nas costas. MÉTODOS: Estudo descritivo com dados do Sistema Único de Informações de Benefícios e dos Anuários Estatísticos da Previdência Social em 2007. A taxa de incidência de dor nas costas como causa das aposentadorias por invalidez foi calculada segundo as variáveis idade e sexo, nos estados. Os dias de trabalho perdidos por invalidez decorrente de dor nas costas foram calculados segundo atividade profissional. RESULTADOS: A dor nas costas idiopática foi a primeira causa de invalidez entre as aposentadorias previdenciárias e acidentárias. A maioria dos beneficiários residia em área urbana e era comerciário. A taxa de incidência de dor nas costas como causa das aposentadorias por invalidez no Brasil foi de 29,96 por 100.000 contribuintes. Esse valor foi mais elevado entre os homens e entre as pessoas mais velhas. Rondônia exibiu taxa quatro vezes superior ao esperado (RT = 4,05 e a segunda maior taxa, referente à Bahia, foi de aproximadamente duas vezes o esperado (RT = 2,07. Os comerciários foram responsáveis por 96,9% dos dias perdidos por invalidez. CONCLUSÕES: A dor nas costas foi uma importante causa de invalidez em 2007, sobretudo entre comerciários, com grandes diferenças entre os estados.

Fisiopatología molecular en la infección por Helicobacter pylori

Directory of Open Access Journals (Sweden)

Franklin Torres Jiménez

2016-01-01

Full Text Available La infección por Helicobacter pylori es el proceso de colonización bacteriana más común a nivel mundial. En 1994 la Agencia Internacional para la Investigación en Cáncer ( IARC catalogó al Helicobacter Pylori como un carcinógeno tipo I. La infección por esta bacteria incrementa el riesgo de padecer cáncer gástrico hasta 6 veces más que los individuos que no presentan la infección. Colombia tiene una prevalencia de infección por Helicobacter pylori del 86 % en adultos mayores de 20 años y del 80% en niños mayores de 8 años. La infección persistente y recidivante de la mucosa gástrica puede generar una respuesta inflamatoria, o procesos silentes, que en el peor de los casos puede progresar a un adenocarcinoma gástrico tipo difuso o intestinal. Existen múltiples factores que influyen en las consecuencias clínicas de la infección por Helicobacter pylori: en mención: predisposición genética del huésped, inmunorregulación genética del paciente infectado, factores ambientales y heterogeneidad de los factores de virulencia de las diversas cepas. Por lo anterior se infiere que las patolo - gías gástricas, en especial la gastritis y el adenocarcinoma, son padecimientos de etiología multifactorial que pueden originarse por diversas causas o condiciones. En esta revisión se analizarán los principales aspectos relacionados con la fisiopatología molecular en la infección por Helicobacter pylori , en particular tópicos correspondientes a los factores de virulencia.

Ansiedad percibida por los pacientes hospitalizados por quemaduras, en una Unidad de Quemados

Directory of Open Access Journals (Sweden)

M. Alcázar-Gabás

2014-06-01

Full Text Available El presente trabajo, pretende describir el estado de ansiedad que experimentan los pacientes ingresados en una Unidad de Quemados. Uno de los factores clave en los cuidados del paciente quemado es una buena atención psicológica. La realidad demuestra que es el profesional de enfermería quien observa los síntomas emocionales durante los primeros días de ingreso y trata de responder a esa demanda de cuidado. Pretendemos, a través de la medición del nivel de ansiedad que perciben los pacientes ingresados en la Unidad de Quemados elegida para nuestro estudio durante el primer semestre del año 2009, identificar a aquellos que estén en riesgo de padecer mayores niveles de ansiedad durante su hospitalización, para así poder establecer un plan de cuidados adaptado a las necesidades emocionales de cada uno. Los resultados obtenidos nos permiten concluir que los pacientes quemados ingresados en la Unidad de Quemados presentaron niveles elevados de ansiedad que son superiores entre la población femenina, así como en aquellos pacientes con lesiones de mayor extensión. Determinamos también que los pacientes ingresados por quemaduras en la Unidad de Quemados a estudio fueron mayoritariamente varones, de nacionalidad española, residentes en medio urbano con una media de edad de 50 años, siendo las quemaduras producidas por llama en accidentes domésticos la causa más frecuente.

Diferencias salariales por género en el departamento de Santander, Colombia

Directory of Open Access Journals (Sweden)

Alexandra Cortés Aguilar

2016-01-01

Full Text Available Este trabajo analiza los factores que influyen en el salario por hora y sus diferencias por género para el departamento de Santander durante los años 2012 a 2014. Específicamente, se explora si dicho diferencial obedece o no a un factor discriminatorio en el mercado de trabajo santandereano, utilizando los datos proporcionados por la Gran Encuesta Integrada de Hogares GEIH. Luego de presentar un análisis descriptivo del mercado laboral santandereano, se realizan estimaciones econométricas aplicando la metodología Blinder-Oaxaca para evidenciar la existencia de un componente discriminatorio. Los resultados indican que, para el total de la muestra en la región santandereana, entre un 25 % y 30 % de las diferencias salariales por género se asocian al componente discriminatorio no explicado.

VENTAJAS ARANCELARIAS OTORGADAS POR ESTADOS UNIDOS POR MEDIO DEL ATPDEA, APROVECHABLES PARA LAS PyMES DE BOGOTA Y CUNDINAMARCA

Directory of Open Access Journals (Sweden)

Mario Ernesto

2003-07-01

Full Text Available En medio de la crisis de desempleo, pobreza y desigualdad que afronta Colombia, las pequeñas y medianas empresas se han convertido en una alternativa importante de generación de trabajo y valor agregado. Sin embargo, éstas deben aprovechar las ventajas que se otorgaron al país en el marco del ATPDEA, por medio del cual los Estados Unidos concedió preferencias arancelarias a más de cinco mil seiscientos productos que estuvieron vigentes durante más de diez años, y que luego, a partir de septiembre del 2002, se ampliaron en más de seiscientos productos. En este trabajo se presentan los rubros de la lista adicional, que presentan posibilidades de exportación a los Estados Unidos por parte de las PyMES de Bogotá y Cundinamarca.

Parâmetros de modelagem por injeção de termoplásticos em moldes fabricados por estereolitografia com resina SOMOS 7110

OpenAIRE

Busato, Fábio André

2004-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Mecânica Este trabalho consistiu em avaliar comparativamente os principais parâmetros envolvidos no processo de moldagem por injeção, utilizando os termoplásticos PP, ABS e PA 6,6, em insertos fabricados pelo processo convencional em aço ABNT 1045 e pelo processo de ferramental rápido por estereolitografia. As cavidades selecionadas tiveram todas a mesma forma geomét...

Consecuencias del estrés oxidativo de la piel por radiaciones ultravioleta

OpenAIRE

Alvarez Fontanet, Ernesto

1995-01-01

Se ha avanzado en el conocimiento de la participación de las especies reactivas del oxígeno en la fisiopatología de muchas entidades y fenómenos patológicos. La piel es probablemente uno de los órganos que con mayor frecuencia sufre estrés oxidativo. Las radiaciones ultravioleta constituyen el principal factor generador de estrés oxidativo a este nivel. El fotoestrés oxidativo de la piel por radiaciones ultravioleta está mediado por diferentes mecanismos y favorecido por diversas circunstanci...

Diferencia salarial por género en ejecutivos peruanos en Lima Metropolitana

OpenAIRE

Gómez Flores, Robert Efrain; Huapaya Ames, Milagros del Carmen; Rojas Zegarra, Jhon Alexander; Salinas Valencia, Eder Velver

2017-01-01

vii, 106 h. : il. ; 30 cm En la presente investigación se describen cuáles son los factores que determinan la diferencia salarial por género en ejecutivos peruanos en Lima Metropolitana y su impacto en cada factor. Dicho estudio se realizó considerando los siguientes factores: (a) estereotipos por género, (b) prejuicios por género, (c) cultura organizacional y (d) educación. Asimismo, esta investigación se basó en un estudio cualitativo, con propósito descriptivo y explicativo,...

Percepções e sentimentos de adolescentes criados por avós

OpenAIRE

Paixão, Flávia Juliana Dourado

2013-01-01

Este estudo tem como objetivo conhecer as percepções e os sentimentos de adolescentes criados por avós. Busca-se, especificamente: 1) descrever a percepção dos adolescentes sobre seus avós, seus sentimentos por eles e as relações estabelecidas com os mesmos; 2) descrever como percebem as figuras parentais biológicas, seus sentimentos por eles e suas relações com os mesmos; 3) compreender a experiência dos adolescentes acerca do fato de serem criados pelos avós; e 4) descrever a...