Effects of mineral sorting on concentrator design and economics

Ore sorting after crushing is an effective way to enhance the feed quality of a concentrator. Sorting by hand is the oldest way of concentrating minerals but it has become outdated because of low capacities. Older methods of sorting have also been difficult to use in large scale productions due to low capacities of sorters. Data transfer and processing and the speed of rejection mechanisms have been the bottlenecks for effective use of sorters. A fictive chalcopyrite ore body was created for this thesis. The properties of the ore were typical of chalcopyrite ores and economical limit was set for design. Concentrator capacity was determined by the size of ore body and the planned mine life. Two concentrator scenarios were compared, one with the sorting facility and the other without sorting. Comparison was made for quality and amount of feed, size of equipment and economics. Concentrator with sorting had lower investment and operational cost but also lower incomes due to the ore loss in sorting. Net cash flow, net present value and internal rate of interest were calculated for comparison of the two scenarios.

Increased expression and purification of soluble iron-regulatory protein 1 from Escherichia coli co-expressing chaperonins GroES and GroEL

Iron is an essential metal for all living organisms. However, iron homeostasis needs to be tightly controlled since iron can mediate the production of reactive oxygen species, which can damage cell components and compromise the integrity and/or cause DNA mutations, ultimately leading to cancer. In eukaryotes, iron-regulatory protein 1 (IRP1) plays a central role in the control of intracellular iron homeostasis. This occurs by interaction of IRP1 with iron-responsive element regions at 5' of ferritin mRNA and 3' of transferrin mRNA which, respectively, represses translation and increases mRNA stability. We have expressed IRP1 using the plasmid pT7-His-hIRP1, which codifies for human IRP1 attached to an NH2-terminal 6-His tag. IRP1 was expressed in Escherichia coli using the strategy of co-expressing chaperonins GroES and GroEL, in order to circumvent inclusion body formation and increase the yield of soluble protein. The protein co-expressed with these chaperonins was obtained mostly in the soluble form, which greatly increased the efficiency of protein purification. Metal affinity and FPLC ion exchange chromatography were used in order to obtain highly purified IRP1. Purified protein was biologically active, as assessed by electrophoretic mobility shift assay, and could be converted to the cytoplasmic aconitase form. These results corroborate previous studies, which suggest the use of folding catalysts as a powerful strategy to increase protein solubility when expressing heterologous proteins in E. coli.

Expression of alpha-synuclein is increased in the hippocampus of rats with high levels of innate anxiety

A genomic region neighboring the alpha-synuclein gene, on rat chromosome 4, has been associated with anxiety- and alcohol-related behaviors in different rat strains. In this study, we have investigated potential molecular and physiological links between alpha-synuclein and the behavioral differences observed between Lewis (LEW) and Spontaneously Hypertensive (SHR) inbred rats, a genetic model of anxiety. As expected, LEW rats appeared more fearful than SHR rats in three anxiety models: open field, elevated plus maze and light/dark box. Moreover, LEW rats displayed a higher preference for alcohol and consumed higher quantities of alcohol than SHR rats. alpha-Synuclein mRNA and protein concentrations were higher in the hippocampus, but not the hypothalamus of LEW rats. This result inversely correlated with differences in dopamine turnover in the hippocampus of LEW and SHR rats, supporting the hypothesis that alpha-synuclein is important in the downregulation of dopamine neurotransmission. A novel single nucleotide polymorphism was identified in the 30-untranslated region (3`-UTR) of the alpha-synuclein cDNA between these two rat strains. Plasmid constructs based on the LEW 3`-UTR sequence displayed increased expression of a reporter gene in transiently transfected PC12 cells, in accordance with in-vivo findings, suggesting that this nucleotide exchange might participate in the differential expression of alpha-synuclein between LEW and SHR rats. These results are consistent with a novel role for alpha-synuclein in modulating rat anxiety- like behaviors, possibly through dopaminergic mechanisms. Since the behavioral and genetic differences between these two strains are the product of independent evolutionary histories, the possibility that polymorphisms in the alpha-synuclein gene may be associated with vulnerability to anxiety- related disorders in humans requires further investigation. Molecular Psychiatry (2009) 14, 894-905; doi: 10.1038/mp.2008.43; published online 22 April 2008

Allium species poisoning in dogs and cats

Dogs and cats are the animals that owners most frequently seek assistance for potential poisonings, and these species are frequently involved with toxicoses due to ingestion of poisonous food. Feeding human foodstuff to pets may prove itself dangerous for their health, similarly to what is observed in Allium species toxicosis. Allium species toxicosis is reported worldwide in several animal species, and the toxic principles present in them causes the transformation of hemoglobin into methemoglobin, consequently resulting in hemolytic anemia with Heinz body formation. The aim of this review is to analyze the clinicopathologic aspects and therapeutic approach of this serious toxicosis of dogs and cats in order to give knowledge to veterinarians about Allium species toxicosis, and subsequently allow them to correctly diagnose this disease when facing it; and to educate pet owners to not feed their animals with Alliumcontaing food in order to better control this particular life-threatening toxicosis.

Implications of groundwater weathered profile interactions to the mobilization of radionuclides

This study reports the nature and extent of open-system interaction between groundwater and a weathered profile developed in the high grade thorium and REE ore body in Morro do Ferro, Pocos de Caldas plateau. The radioelement mobility in the shallow oxidizing environment was considered by using chemical data in conjunction with U-234/U-238, Ra-226/Th-230, Th-230/U-234, Th-228/Th-232, Ra-228/Th-232 and Th-230/Ra-228 activity ratios (AR's) for borehole spoil and groundwater samples.Recharging groundwater from the studied borehole has low salinity values, with total dissolved solids content of 14.7 mg/l and total ionic strength of 0.00018. The ratio of the weight of dissolved radioelement per unit volume of solution to the weight of radioelement in solid phase per unit weight of solid phase showed that the radioelement solubility in the studied waters varied according to the following order: radium> uranium >thorium.U-234/U-238 AR's less than 1 were measured in solid phase and can justify the enhancement of U-234 in solution. Ra-226/Th-230 AR's greater than 1 and Th-230/U-234 AR'S less than 1 were evaluated between 20 and 27 m in depth, where a 2.1-m thick magnetite dike was intersected. These ratios could be justified by deposition of U and Ra associated with Fe-Mn oxides and kaolinite, where mineral saturation indices evaluated from the available data confirm this possibility. Covariations among disequilibria involving Th-228/(228) Ra and Ra-228/Th-232 AR's showed the preferential removal of Ra-228 relative to Tn isotopes, Th-228 and Th-232. The recent deposition of radium within the timescale of at least the last 35 years also is suggested. (C) 1998 Elsevier B.V. Ltd. All rights reserved.

The behavior of dissolved uranium in groundwaters of the Morro do Ferro thorium deposit, Brazil

Groundwater samples were collected for several months in boreholes drilled at Morro do Ferro, a thorium and rare earth deposit located on the Poços de Caldas Plateau, Minas Gerais State, Brazil. An aquifer system has developed in the weathered mantle due to in situ intense alteration. The weathered zone includes a thick argillaceous laterite greater than 100 m thick. The U content and 324U/238U activity ratio were measured in the groundwater samples and in spoil samples of a borehole drilled in the ore body. Some possible mechanisms related to the mobilization of uranium are considered such as complexation with humic substances and adsorption by clays. © 1989.

Sintering of porous alumina obtained by biotemplate fibers for low thermal conductivity applications

In this research report, a sintering process of porous ceramic materials based on Al2O3 was employed using a method where a cation precursor solution is embedded in an organic fibrous cotton matrix. For porous green bodies, the precursor solution and cotton were annealed at temperatures in the range of 100-1600°C using scanning electron microscopy (SEM) and thermogravimetric (TG) analysis to obtain a porous body formation and disposal process containing organic fibers and precursor solution. In a structure consisting of open pores and interconnected nanometric grains, despite the low porosity of around 40% (calculated geometrically), nitrogen physisorption determined a specific surface area of 14m2/g, which shows much sintering of porous bodies. Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analytical methods revealed a predominant amount of α-Al2O3 in the sintered samples. Thermal properties of the sintered Al2O3 fibers were obtained by using the Laser Flash which resulted in the lower thermal conductivity obtained by α-Al2O3 and therefore improved its potential use as an insulating material. © 2012 Elsevier Ltd.

Anomalias eletromagnéticas de corpos tubulares inclinados em contato com o manto de intemperismo usando diferentes arranjos de bobinas-modelamento analógico

A principal aplicação dos métodos eletromagnéticos é a prospecção de sulfetos maciços que pela própria natureza geológica são corpos longos e delgados, encrustados em rocha encaixante resistiva, permitindo a interpretação através de curvas de modelos reduzidos usando semi-planos em meio resistivo (ar-livre). No entanto, com a extensão do uso dos métodos eletromagnéticos em regiões que tem um manto de intemperismo de parcialmente condutivo a condutivo, como na região Amazônica e nas regiões semi-áridas ou de climas tropicais , esta técnica de interpretação tem levado a resultados bem diferentes da situação real. O objetivo deste trabalho é estudar a influência do manto de intemperismo em contato ôhmico com o corpo-alvo, utilizando os arranjos de bobinas horizontal coplanar (HCP), vertical coplanar (VCP), vertical coaxial (VCA) e mínimo (PERP), através do modelagem analógico. Para simular o corpo foram utilizadas placas de grafite, cujas dimensões satisfazem a condição de semi-plano. Para simular o manto foi usada uma solução de cloreto de amônia. De forma geral, os resultados obtidos com os diversos arranjos apresentaram as mesmas características, ressalvada as diferenças peculiares de cada arranjo. De forma resumida tem-se as seguintes alterações na anomalia atribuídas à um manto condutivo em contato ôhmico com o corpo-alvo: i) Há rotação de fase, que inicialmente é em sentido anti-horário, mas mais adiante, com o aumento do número de indução do manto , torna-se horária; ii) Alteração na forma padrão do perfil de quadratura devido ao surgimento do pico extra no lado a favor do mergulho; iii) Só há uniformidade de comportamento para o pico-a-pico contra da quadratura, que cresce com o aumento número de indução do manto. Maiores anomalias são obtidas com o sistema horizontal coplanar e as menores com o vertical coplanar. Neste estudo não foi observado formação de pico extra nas anomalias do arranjo vertical coplanar. Ainda, os efeitos de cobertura são mais acentuados no sistema horizontal coplanar comparados aos sistemas de bobina vertical e em anomalias de semi-planos menos inclinados e em menor profundidade.

Efeitos do manto de intemperismo sobre anomalias eletromagnéticas provocadas por corpos tabulares inclinados: um estudo através de modelamento reduzido

Electromagnetic methods have been extensively applied in the prospecting of sulphide bodies and other conducting materials. The interpretation of e. m. data is based on the results obtained either with reduced scale or analytical modelling. In most models, the host rocks, the overburden as well as the halo of disseminated sulphides are considered highly resistive although in nature they are often weakly conductive. Presence of a well-developed conducting overburden in tropical and sub-tropical regions and a saline rich crustal layer in semi-arid regions have been found to modify significantly the e. m. anomalies in practice. Therefore, the parameters of the target, determined on the basis of simple models where the presence of the conducting environment is neglected, are found to be in considerable error. The effects of the overburden on the e. m. anomalies of a dipping tabular ore body were studied with reduced scale models for varying response parameters of both the overburden and the orebody, and also for different depths and dips of the target. The overburden and the orebody were represented by metallic sheets of varying thickness in the scale model developed in accordance with the law of electromagnetic similitude. The results of these investigations show that the overburden affects the anomaly by causing: a) phase rotation; b) amplitude reduction; c) base level displacement; d) reversion of the quadrature; and e) appearance of an extra peak in the quadrature in the case of low dipping models. The last two effects complicate the quantification of the anomalies but, on the other hand, provide a qualitative indication of the response parameters of both the ore body and the overburden. The results were assembled in the form of Argand diagrams and, finally, an interpretation scheme is suggested for the e. m. field data on the basis of these diagrams.

Efeitos do manto de intemperismo sobre anomalias “VLF” dos corpos tabulares inclinados

A utilização dos métodos indutivos de propagação E.M. na exploração mineral em regiões tropicais, apresenta grandes dificuldades devido a presença de uma camada superficial condutiva (manto de intemperismo) comumente encontrada nestas regiões. Na região Amazônica, o manto apresenta-se bastante desenvolvido e condutivo, e em regiões semi-áridas, pode-se formar uma fina crosta superficial de sal. Em conseqüência disto, a interpretação dos dados E.M. obtidos para modelos que não consideram uma cobertura condutiva levam a erros consideráveis. Objetivando-se estudar os efeitos do manto sobre anomalias VLF devidas a corpos tabulares inclinados em contato com o manto (manto ohmico), foi realizada uma série de experimentos através do modelamento analógico, considerando-se diferentes parâmetros de resposta para o manto e o corpo. O manto de intemperismo foi simulado por soluções de cloreto de amônia (NH₄Cl) dispostas horizontalmente e o corpo condutor por chapas de grafite colocadas em posições inclinadas verticalmente. Utilizou-se quatro corpos condutores e três mantos com diferentes espessuras e condutividades, simulando, desta forma, diversas situações geológicas. Os resultados são dados por simples situações dos corpos localizados em um meio não condutor (ar), onde os parâmetros variados são: profundidade do topo, condutividade e mergulho do corpo. Os efeitos da condutividade da cobertura são amplamente ilustrados e avaliados. Para a análise dos resultados, foi plotado um conjunto de curvas considerando-se os valores pico-a-pico das anomalias de "tilt angle" e de elipsidade. Os resultados foram sintetizados em um outro conjunto de curvas reunidas em diagramas de Argand. Estando ou não o manto presente, observou-se, tanto para o tilt angle quanto para a elipsidade, o efeito do aumento da profundidade é o de reduzir a magnitude pico-a-pico e a forma do pico da anomalia, fazendo com que este afaste-se do ponto de "cross-over". Para um condutor de mesma espessura, o aumento da condutividade causa um ligeiro aumento nas anomalias de tilt angle, e uma atenuação nas anomalias de elipsidade. O efeito geral na variação do mergulho do condutor é o de causar uma assimetria nos perfis de tilt angle e de elipsidade. O aumento da condutância do manto de intemperismo causa um acréscimo nas anomalias de elipsidade e uma ligeira diminuição nas anomalias de tilt angle; porém, a partir de um certo valor de condutância do manto (mantos mais condutivos) tanto as anomalias de tilt angle quanto as anomalias de elipsidade começam a atenuar. Há rotação de fase no sentido anti-horário, sendo mais intensa para grandes valores de número de indução do corpo. Na presença do manto, o corpo parece estar a uma profundidade inferior à verdadeira e a ser menos condutivo.

Estudo de anomalias eletromagnéticas de um condutor tabular vertical sob camadas parcialmente condutiva em multifrequência e multiseparação através de modelamento analógico

A resposta eletromagnética (EM) de um corpo condutivo envolvido por uma zona parcialmente condutiva, torna-se bastante diferente daquela de um corpo condutivo em um meio altamente resistivo. As zonas parcialmente condutivas, como por exemplo, rocha encaixante, halo de sulfetos disseminados ou manto de intemperismo, que envolvem o corpo condutivo, afetam a resposta EM de diferentes maneiras, dependendo de suas características físicas e geométricas e, em particular, do sistema de prospecção EM utilizado. Neste trabalho em modelamento analógico, foi feita uma análise de anomalias EM provocadas por corpos condutivos tabulares verticais sob manto de intemperismo, em levantamentos terrestres para diferentes sistemas de bobinas - horizontal coplanar, vertical coplanar e vertical coaxial - em oito frequências na faixa de 250 Hz a 35 kHz e separações entre as bobinas de 0,15; 0,20 e 0,25m. O manto de intemperismo foi simulado por folhas de aço finas dispostas horizontalmente e o corpo condutor principal por folhas de alumínio finas colocadas verticalmente. As dimensões das folhas foram determinadas de acordo com as condições de modelamento para o plano e o semi-plano. Foram utilizados três corpos e três mantos com diferentes espessuras e condutividades, simulando, deste modo, diversas situações geológicas. Os resultados mostraram que cada sistema de bobinas é afetado diferentemente pela presença do manto de intemperismo. Para a análise dos resultados foi plotado um conjunto de diagramas considerando os valores pico-a-pico das anomalias em fase e em quadratura. Um outro conjunto de diagramas mostra as amplitudes máximas em fase, que ocorrem quando a componente em quadratura se anula em uma frequência relativamente baixa para um conjunto de corpo-manto, e as amplitudes máximas em quadratura, que ocorrem quando a resposta em fase atinge um mínimo próximo de zero, em frequências relativamente altas. Com isto foi possível conhecer a faixa de frequências para cada sistema de bobinas, onde a resposta EM se encontra o mínimo afetada pela presença do manto de intemperismo. A maior amplitude na resposta é obtida no sistema horizontal coplanar e a menor no sistema vertical coplanar. Um aumento na separação entre as bobinas é acompanhado por um deslocamento da anomalia para baixas frequências. A faixa de frequências, onde a presença do manto tem pouca influência na resposta do corpo condutivo, e maior para o sistema vertical coaxial e menor para o sistema horizontal coplanar. Esses resultados dão uma luz para o conhecimento da posição e da largura da banda de frequências utilizável, assim como as melhores separações entre transmissor-receptor, para auxiliar no planejamento de sistemas de prospecção EM, de modo que a resposta fique o mais livre possível de sinais indesejáveis, tais como os causados pela presença do manto de intemperismo.

The COP9 signalosome counteracts the accumulation of cullin SCF ubiquitin E3 RING ligases during fungal development

Defects in the COP9 signalosome (CSN) impair multicellular development, including embryonic plant or animal death or a block in sexual development of the fungus Aspergillus nidulans. CSN deneddylates cullin-RING ligases (CRLs), which are activated by covalent linkage to ubiquitin-like NEDD8. Deneddylation allows CRL disassembly for subsequent reassembly. An attractive hypothesis is a consecutive order of CRLs for development, which demands repeated cycles of neddylation and deneddylation for reassembling CRLs. Interruption of these cycles could explain developmental blocks caused by csn mutations. This predicts an accumulation of neddylated CRLs exhibiting developmental functions when CSN is dysfunctional. We tested this hypothesis in A. nidulans, which tolerates reduced levels of neddylation for growth. We show that only genes for CRL subunits or neddylation are essential, whereas CSN is primarily required for development. We used functional tagged NEDD8, recruiting all three fungal cullins. Cullins are associated with the CSN1/CsnA subunit when deneddylation is defective. Two CRLs were identified which are specifically involved in differentiation and accumulate during the developmental block. This suggests that an active CSN complex is required to counteract the accumulation of specific CRLs during development.

A pure population of lung alveolar epithelial type II cells derived from human embryonic stem cells.

Alveolar epithelial type II (ATII) cells are small, cuboidal cells that constitute approximately 60% of the pulmonary alveolar epithelium. These cells are crucial for repair of the injured alveolus by differentiating into alveolar epithelial type I cells. ATII cells derived from human ES (hES) cells are a promising source of cells that could be used therapeutically to treat distal lung diseases. We have developed a reliable transfection and culture procedure, which facilitates, via genetic selection, the differentiation of hES cells into an essentially pure (>99%) population of ATII cells (hES-ATII). Purity, as well as biological features and morphological characteristics of normal ATII cells, was demonstrated for the hES-ATII cells, including lamellar body formation, expression of surfactant proteins A, B, and C, alpha-1-antitrypsin, and the cystic fibrosis transmembrane conductance receptor, as well as the synthesis and secretion of complement proteins C3 and C5. Collectively, these data document the successful generation of a pure population of ATII cells derived from hES cells, providing a practical source of ATII cells to explore in disease models their potential in the regeneration and repair of the injured alveolus and in the therapeutic treatment of genetic diseases affecting the lung.

Unraveling environmental drivers of a recent increase in Swiss fungi fruiting

Disentangling biotic and abiotic drivers of wild mushroom fruiting is fraught with difficulties because mycelial growth is hidden belowground, symbiotic and saprotrophic supply strategies may interact, and myco-ecological observations are often either discontinuous or too short. Here, we compiled and analyzed 115 417 weekly fungal fruit body counts from permanent Swiss inventories between 1975 and 2006. Mushroom fruiting exhibited an average autumnal delay of 12 days after 1991 compared with before, the annual number of fruit bodies increased from 1801 to 5414 and the mean species richness doubled from 10 to 20. Intra- and interannual coherency of symbiotic and saprotrophic mushroom fruiting, together with little agreement between mycorrhizal yield and tree growth suggests direct climate controls on fruit body formation of both nutritional modes. Our results contradict a previously reported declining of mushroom harvests and propose rethinking the conceptual role of symbiotic pathways in fungi-host interaction. Moreover, this conceptual advancement may foster new cross-disciplinary research avenues, and stimulate questions about possible amplifications of the global carbon cycle, as enhanced fungal production in moist mid-latitude forests rises carbon cycling and thus increases greenhouse gas exchanges between terrestrial ecosystems and the atmosphere.

The ATHENA experiment for the study of antihydrogen

In 2002, the ATHENA experiment was the first to produce large amounts of antihydrogen atoms at the CERN Antiproton Decelerator (AD). In this review article, we collect and discuss all the relevant results of the experiment: antiproton and positron cooling and their recombination dynamics in the nested Penning trap, the methods used to unambiguously identify the antiatoms as well as the protonium background, the dependence of the antihydrogen formation on mixing time and temperature. An attempt to interpret the results in terms of the two-body and three-body formation reactions, taking into account the complicated nested-trap dynamics, is also made. The relevance of the ATHENA results on future experiments is discussed, together with a short overview of the current antimatter physics at the AD.