120 research outputs found
FLOATING ELBOW IN CHILDREN: A DESCRIPTIVE STUDY OF 31 CASES ATTENDED IN A REFERENCE CENTER FOR PEDIATRIC TRAUMA
ABSTRACTObjective: To conduct a descriptive analysis on 31 cases of children with floating elbow who were attended at our clinic between 1994 and 2009, and to review the literature relating to this topic. Methods: Data were obtained through examining the medical records. The following variables were used: age, gender, side, mechanism, type of fracture, classification, treatment and complications. Results: Twenty-four patients (77.4%) were male and seven (22.6%) were female. The mean age was 8.5 (± 3.2) years, ranging from one to 14 years. The left side was predominantly affected (67.7%). The commonest injury mechanism was a fall from a height (74.2%). All the supracondylar fractures were Gartland type III. Distal radius fractures alone, of Salter-Harris type II, were diagnosed in 22 patients (71%). Open fractures occurred in 22 cases (71%). Closed reduction and application of a plaster cast for a closed fracture of the distal radius was performed in two patients (6.45%). Simultaneous conservative treatment for two fractures was not used. Sixteen supracondylar fractures (54.8%) were fixed using crossed wires, at 90° to each other, and in 14 cases (45.16%), an intramedullary wire was used together with another wire introduced through the lateral epicondyle at 45°. The following complications were observed: deformed consolidation (10%), nerve injuries (6%), compartment syndrome (3%) and pin path infection (16%). Conclusions: This is an uncommon injury that in most cases results from high-energy trauma. Surgical treatment for both fractures is recommended by most authors. Ulnar nerve injuries were correlated with the fixation method, but no neurological injuries were triggered by the initial trauma
Effects of conductive and non-conductive materials on the activity of a hydrogenotrophic methanogen
Several conductive materials (CM), such as carbon nanotubes (CNT), activated carbon (AC), and magnetite, have been reported to mediate interspecies electron transfer in methanogenic environments. However, CNT also accelerated methane production (MP) of pure cultures of methanogens. We hypothesize that other CM and also non-CM may affect the methanogenic activity of pure cultures. For that purpose, we incubated the hydrogenotrophic methanogen, Methanobacteriun formicicum strain DSM 1535T, with AC, zeolite (Zeo), sand and glass beads (at 0.5 g/L), and followed MP. All materials reduced lag phases preceding the MP, and the time for complete conversion of H2/CO2 to methane. The best results were obtained with Zeo, since total hydrogen conversion occurred in less than 5 days (instead of 8 days as in the control incubated without materials). Approximately 5 days with sand, and 6 days with glass beads and AC, were necessary to achieve the complete conversion. The lag phases with AC were quite short (1 day) when compared with the control assay without materials (5 days). The initial MP (determined during the first 3 days of incubation) was improved 16 times with Zeo and 11 times with AC, when compared with the cultures incubated without materials. The results show that there is not a direct relationship between conductivity and the improvement of methanogenic activity. Other physicochemical properties of the materials might be related with the beneficial effects towards methanogens.info:eu-repo/semantics/publishedVersio
Zeolite stimulates the activity of microbial enrichments converting butyrate to methane
Conductive materials have been tested as a strategy to improve methane production (MP) in anaerobic digestion (AD) processes1,2. The effect of zeolite (0.5 g/L) towards microbial enrichments converting butyrate (10 mmol/L) to methane was investigated and compared with a microbial enrichment in the absence of the material. The enrichments were initiated with granular anaerobic sludge from a brewery WWTP as inoculum. Incubations were carried out under strict anaerobic conditions (at 37 °C) and periodically transferred to fresh medium.
The results showed that, after an initial adaptation period (3 transfers), the presence of zeolite significantly accelerated the total conversion of butyrate to methane, since it took approximately 30d with zeolite and around 45d without zeolite. However, both enrichment cultures after extended adaptation (more than 8 transfers) behaved similarly, degrading butyrate in approximately 15d. Nevertheless, zeolite addition to active butyrate enrichment cultures without previous contact with zeolite, slightly accelerated MP, while the highly adapted zeolite-enrichment decreased activity when incubated without zeolite.
Thus, the presence of zeolite showed to stimulate the microbial activity enhancing MP from butyrate degradation. This material possess natural ion-exchange properties, absorptive capacity and could function as a support for biomass which makes its application very attractive to AD processes.info:eu-repo/semantics/publishedVersio
Pure cultures of hydrogenotrophic methanogens are affected by modified activated carbons, zeolite, sand and glass beads
The metabolism of hydrogenotrophs has been showed to be improved in the presence of carbon nanotubes, which is relevant since they are crucial microorganisms in the conversion of waste to methane1. In this study, we investigated if other materials, with different physicochemical properties, also affect the hydrogenotrophic activity of Methanobacterium formicicum.
M. formicicum was incubated separately with 0.5 g/L of sand, and commercial zeolite, glass beads and activated carbon (AC0) with and without modifications on the AC0 surface. Modifications were obtained by chemical oxidation with HNO3 (AC_HNO3), H2SO4 (AC_ H2SO4) or both (AC_HNO3_ H2SO4) and thermal treatments.
All materials, with exception of AC_HNO3_ H2SO4, improved the methanogenic activity. Carbon-based materials significantly reduced the lag phases preceding methane production (MP) (from approximately 5 days in the control to circa 1 day). Zeolite, sand and glass beads also reduced the lag phases but less than carbon materials (i.e., from 5 days to 1.5, 2.7 and 3.5 days, respectively). Additionally, exponential MP rates were up to 1.5 times higher in the assays with non-carbon materials.
All materials tested have different physical/chemical properties including conductivities, but all stimulated the methanogenic activity. Thus, further studies are necessary to identify the mechanisms behind the underlying observations.info:eu-repo/semantics/publishedVersio
TEOR DE MACRO E MICRONUTRIENTES E POTENCIAL FISIOLÓGICO DE SEMENTES EM GENÓTIPOS CRIOULO E MELHORADO DE FEIJÃO
O feijão é cultivado principalmente por agricultores familiares, que geralmente utilizam sementes de anos anteriores, selecionadas pelos próprios agricultores, caracterizando-as como sementes crioulas, apresentando alto potencial para o uso direto pelos agricultores e utilização em programas de melhoramento. O trabalho teve o objetivo de avaliar a qualidade fisiológica e o teor de nutrientes em sementes de cultivares crioulas e melhoradas por seleção participativa, e a influência do teor desses nutrientes no potencial fisiológico das sementes. Foram utilizadas sementes provenientes dos ensaios de avaliação de cultivares conduzidos em São Luiz Gonzaga e Sobradinho, RS, da safra 2012. Foram avaliadas nas sementes os teores de: fósforo, cálcio, potássio, ferro, magnésio, zinco e manganês nas sementes. Também foram avaliados a qualidade fisiológica por meio de: germinação, envelhecimento acelerado, teste de frio, condutividade elétrica e comprimento de raiz e parte aérea nas plântulas. Concluiu-se que as sementes das cultivares crioulas e melhoradas por seleção participativa apresentam elevado potencial fisiológico. Os genótipos AM-10, AS-7, Preto Ibérico TB 02-21 e ZL-1 destacaram-se pelo maior potencial fisiológico das sementes. Existe interação entre genótipo e ambiente para teor de nutrientes nas sementes. O teor de nutrientes exerce influência na qualidade das sementes, principalmente fósforo, cálcio, ferro e manganês
Modulation of butyrate-degrading methanogenic communities by conductive materials
Butyrate is a volatile fatty acid commonly present in anaerobic bioreactors. Previous research showed that methane production (MP) rates from butyrate, by lake sediment microbiomes, doubled by addition of carbon nanotubes, which was accompanied by changes in the microbial community composition, with enrichment of typical fatty-acid degrading bacteria (Syntrophomonas spp.), well known to exchange electrons with methanogens via hydrogen or formate formation1. But the authors suggested that electrons exchange via conductive materials (CM) may take place instead.
In our study, anaerobic butyrate-degrading enrichment cultures were developed with other CM, namely activated carbon (AC) and magnetite (Mag) at 0.5 g/L. MP started earlier in AC enrichment and complete degradation was achieved faster in Mag enrichment. Syntrophomonas spp. were enriched in all cultures (representing 60 to 80 % of the total bacterial community), but hydrogenotrophic methanogens were highly stimulated by AC (78 % of Methanomicrobiales), while the methanogenic community of Mag culture was more diverse in acetoclastic methanogens (43% of Methanosarcina and Methanosaeta). It is still unclear if the improvement on butyrate degradation is associated to the role of CM in interspecies electron transfer, but it is undoubtful that they differentially modulate the methanogenic communities towards faster MP.info:eu-repo/semantics/publishedVersio
Differential effects of carbon-based and iron-based conductive materials in anaerobic butyrate-degrading enrichments
Introduction
Conductive materials (CM) accelerate methane production (MP), probably by promoting more efficient interactions between bacteria and methanogens.
This work investigates the effects of activated carbon (AC) and magnetite (Mag) in microbial enrichments degrading butyrate. Three different butyrate-degrading enrichments were developed: 1) without CM, 2) with AC, or 3) with Mag. It was also investigated if the effect of CM persisted when CM-adapted enrichments were transferred to new medium without CM, and if CM affected the activity of stable enrichments without previous contact with CM.
Methodology
Enrichment series were initiated with granular anaerobic sludge as inoculum, butyrate (10 mmol/L) as substrate, and CM (0.5 g/L AC or 0.5 g/L Mag), or without CM, and incubated at 37 °C, under strict anaerobic conditions.
The following parameters were monitored: methane by gas chromatography; butyrate and acetate by high performance liquid chromatography; oxidation-reduction potential; pH and conductivity. RNA was extracted and taxonomic composition of the microbial communities was obtained by 16S rRNA gene sequencing.
Results
During the first incubations, AC-enrichment consumed hydrogen derived from butyrate degradation within 4 days, which was much faster than the enrichments with Mag and without CM, which presented lag phases (LP), preceding MP, longer than 11 and 7 days, respectively. Thus, Mag probably inhibited butyrate-degrading bacteria and/or hydrogenotrophic methanogens. Conversely, after the lag phase, Mag-enrichment was the fastest converting acetate to methane (3 times faster than in AC-enrichment), suggesting a stimulatory effect of Mag towards acetoclastic methanogens.
Nevertheless, once the enrichments were adapted to the growth conditions, more efficient butyrate conversion was observed by all enrichments, with lag phases lower than 4 days, even in the control-enrichment.
No significant changes on butyrate degradation were observed when highly adapted CM-enrichments were transferred to fresh medium without CM. On the other hand, when active enrichments (without previous contact with CM), were incubated with AC, it became slightly faster (0.7 times shorter LP), and with Mag were greatly inhibited (12 times longer LP).
Syntrophomonas spp. represented 60 to 80 % of the total bacterial communities in all enrichments. Hydrogenotrophs were more abundant in AC-enrichment (78 % of Methanomicrobiales) and Mag-enrichment was highly enriched in acetoclastic methanogens (43 % of microorganisms assigned to Methanosaeta and Methanosarcina).
Conclusions
The presence of CM affects the performance of butyrate-degrading communities, with AC accelerating particularly butyrate conversion to methane (via H2/CO2) and acetate, and Mag inhibiting that first step but stimulating acetate conversion to methane.info:eu-repo/semantics/publishedVersio
Conductive materials affect methanogenic activity of pure cultures of methanogens and syntrophic cocultures
info:eu-repo/semantics/publishedVersio
Formar bem as mães para criar e educar boas crianças: as revistas portuguesas de educação familiar e a difusão da maternidade científica (1945-1958)
Este artigo tem como principal objetivo contribuir para a compreensão do processo de construção da maternidade científica em Portugal. Neste sentido, foi analisado um conjunto de artigos (n=628), publicados em revistas de educação familiar, entre 1945 e 1958. A análise realizada permitiu compreender que as revistas analisadas contribuem para a difusão da maternidade científica, ou seja, da ideia de que a aquisição de conhecimento científico sobre a criação e educação das crianças é elemento indispensável ao adequado exercício da função maternal. Observou-se, ainda, a existência de diferentes estratégias de educação para a maternidade, às quais está subjacente um elemento de classe, assim como diferentes níveis de adesão, por parte das mulheres, à concepção de maternidade científica
Evaluation of cysteamine associated with different energy patterns in diets for broiler chickens
- …