Relación entre la entalpía de inmersión de monolitos de carbon activado y parametros texturales

In this study, Disc and honeycomb-shaped activated carbon monoliths were obtained using as a precursor coconut shell, without the use of any binder. Textural characterization was performed by adsorption of N2 at 77 K and immersion calorimetry into benzene. The experimental results showed that the activation with zinc chloride produces a wide development of micropores, yielding micropore volumes between 0,38 and 0,79 cm³ g-1, apparent BET surface area between 725 and 1523 m² g-1 and immersion enthalpy between 73,5 and 164,2 J g-1.Were made comparisons between textural parameters and energy characteristics.

Klarer Himmel

Soitinnus: piano.

Early Detection of Alzheimer's Disease Beta-amyloid Pathology -Applicability of Positron Emission Tomography with the Amyloid Radioligand 11C-PIB

Early Detection of Alzheimer's Disease Beta-amyloid Pathology -Applicability of Positron Emission Tomography with the Amyloid Radioligand ¹¹C-PIB Accumulation of beta amyloid (Abeta) in the brain is characteristic for Alzheimer’s disease (AD). Carbon-11 labeled 2-(4’-methylaminophenyl)-6-hydroxybenzothiazole (¹¹C-PIB) is a novel positron emission tomography (PET) amyloid imaging agent that appears to be applicable for in vivo Abeta plaque detection and quantitation. The biodistribution and radiation dosimetry of ¹¹C-PIB were investigated in 16 healthy subjects. The reproducibility of a simplified ¹¹C-PIB quantitation method was evaluated with a test-retest study on 6 AD patients and 4 healthy control subjects. Brain ¹¹C-PIB uptake and its possible association with brain atrophy rates were studied over a two-year follow-up in 14 AD patients and 13 healthy controls. Nine monozygotic and 8 dizygotic twin pairs discordant for cognitive impairment and 9 unrelated controls were examined to determine whether brain Abeta accumulation could be detected with ¹¹C-PIB PET in cognitively intact persons who are at increased genetic risk for AD. The highest absorbed radiation dose was received by the gallbladder wall (41.5 mjuGy/MBq). About 20 % of the injected radioactivity was excreted into urine, and the effective whole-body radiation dose was 4.7 mjuSv/MBq. Such a dose allows repeated scans of individual subjects. The reproducibility of the simplified ¹¹C-PIB quantitation was good or excellent both at the regional level (VAR 0.9-5.5 %) and at the voxel level (VAR 4.2-6.4 %). ¹¹C-PIB uptake did not increase during 24 months’ follow-up of subjects with mild or moderate AD, even though brain atrophy and cognitive decline progressed. Baseline neocortical ¹¹C-PIB uptake predicted subsequent volumetric brain changes in healthy control subjects (r = 0.725, p = 0.005). Cognitively intact monozygotic co-twins – but not dizygotic co-twins – of memory-impaired subjects exhibited increased ¹¹C-PIB uptake (117-121 % of control mean) in their temporal and parietal cortices and the posterior cingulate (p<0.05), when compared with unrelated controls. This increased uptake may be representative of an early AD process, and genetic factors seem to play an important role in the development of AD-like Abeta plaque pathology. ¹¹C-PIB PET may be a useful method for patient selection and follow-up for early-phase intervention trials of novel therapeutic agents. AD might be detectable in high-risk individuals in its presymptomatic stage with ¹¹C-PIB PET, which would have important consequences both for future diagnostics and for research on disease-modifying treatments.

L'Univers

1887/10/30 (Numéro 725).

Método rápido de extração de DNA de bactérias

Desenvolveu-se um método rápido para extração de DNA de bactérias, que ao contrário de outros métodos, não requer o uso de enzimas, como lisozima e proteinase K, previamente, utilizado-se o carbonato de silício (carborundum) como agente físico para efetuar a quebrar da parede celular da bactéria. Com este método conseguiu-se extrair DNA bacteriano num menor tempo, além de mais rápido, ele mostrou-se mais simples e econômico, quando comparado aos métodos convencionais. O DNA obtido pode ser utilizado para diversas finalidades relacionadas ao DNA de bactérias, obtendo-se uma quantidade razoável de DNA, que varia de 725 µg/mL a 1170 µg/mL por cada 0,1 g de célula bacteriana, com ótima qualidade.

Imagon merkitys paikan markkinoinnissa: Kaupunki-imagon nykytila kohderyhmittäin

Tämän tutkimuksen tarkoituksena oli selvittää imagon merkitystä kohde-ryhmälähtöisessä paikan markkinoinnissa. Tavoitteena oli mitata kaupun-gin ulkoisen imagon nykytilaa ja tunnistaa paikan markkinoinnin keskeisiä kohderyhmiä. Tutkimuksessa arvioitiin miten kaupunki-imagot vaihtelivat kohderyhmittäin ja mitä viestintäkanavia kohderyhmät käyttivät tiedon-hakuun. Tutkimuksen kohteena oli vuoden 2009 alussa monikuntaliitoksen myötä syntynyt uusi Kouvola, Suomen 10. suurin kaupunki. Empiirinen osa toteutettiin kvantitatiivisena, kuvailevana ja kartoittavana, kyselytutkimuk-sena Helsingissä Oma Koti -09 messutapahtumassa. Pääkohderyhmänä olivat pääkaupunkiseudun asukkaat. Pääosalla kyselyyn vastanneista (n=725) oli omakohtainen kokemus Kouvolasta ja tietoa vastaajat hakivat eniten internetistä. Johtopäätöksenä voidaan todeta että kokonaismielikuva Kouvolan imagosta oli yli 80 %:sesti positiivinen. Kaupunki-imago ei vaihdellut suuresti tunnis-tettujen kohderyhmien välillä. Imagoattribuuttien perusteella imago perustui kodikkuuteen ja hyvään arkeen. Kaupunkia pidetään asumisen ja vapaa-ajanvieton kannalta vetovoimaisena. Muuttohalukkuuteen vaikuttivat eniten elämäntilanne, kesämökin tai työpaikan löytyminen.

Semeadura direta de canafístula (Peltophorum dubium (Spreng.)taub. No enriquecimento de capoeiras

O presente trabalho teve por objetivo avaliar o comportamento da canafistula (Peltophorumdubium), em semeadura direta a campo, em área de capoeira originada após o abandono do local utilizado com cultivos agrícolas sucessivos. No local foram roçadas faixas de 1,5 m, a cada 3 m. A semeadura foi realizada em setembro de 1997. Visando proteger os pontos semeados, foram utilizados diferentes tipos de protetores (copos de plástico e copos de papel, sem fundo e laminado de madeira), fixados sobre os pontos semeados com três sementes cada. As sementes foram escarificadas mecanicamente a 1.725 rpm, durante 60 segundos, com lixa Norton 60. O delineamento foi em blocos casualizados, com seis repetições. As variáveis avaliadas foram emergência, sobrevivência, número de pontos com plantas, densidade a 1 ano e altura das plantas aos 18 meses. Os resultados obtidos aos nove meses demonstraram que a utilização de qualquer um dos protetores físicos contribuiu para o estabelecimento de plantas em mais de 80% dos pontos semeados, e em mais de 75%, um ano após a semeadura, quando utilizado o laminado, o que indica que a semeadura direta é uma alternativa de implantação para a espécie, possibilitando transformar as áreas de capoeiras em um sistema agroflorestal ou mesmo silvipastoril, no futuro.

Application of response surface methodology to study the biological removal of nitrogen from effluent of cattle slaughterhouse in a sequencing batch reactor

The aim of this study was to evaluate the efficiency of a sequencing batch reactor (SBR) on biological removal of nitrogen from cattle slaughterhouse wastewater by nitrification/denitrification processes. The effects of initial concentration of ammoniacal nitrogen were investigated at 100; 150 and 200 mg L-1 and air flow rate at 0.125; 0.375 and 0.625 L min¹ Lreactor-1 on the nitrogen compounds removal, by a Central Composite Rotational Design (CCRD) configuration. There were variations from 9.2 to 94.9%, 4.0 to 19.6% and 20.8 to 92.0% in the conversion of ammoniacal nitrogen to nitrate and nitrite concentration and removal of total nitrogen, respectively. The increase of air flow rate and decrease of the initial concentration of ammoniacal nitrogen resulted in higher efficiencies of total nitrogen removal, as well as the conversion of ammoniacal nitrogen to nitrate. During the pre-established intervals of this study, the removal and conversion efficiencies of nitrogen compounds above 85% were achieved in air flow rate variations from 0.375 to 0.725 L min-1 Lreactor-1 and initial concentration of ammoniacal nitrogen from 80 to 200 mg L-1. On denitrification process, we obtained efficiencies from 91.5 to 96.9% on the removal of nitrite/nitrate and from 78.3 to 87.9% on the removal of organic matter.

L'Univers

1869/04/23 (Numéro 725).

Comparison of two commercial kits and two extraction methods for fecal glucocorticoid analysis in ocelots (Leopardus pardalis) submitted to ACTH challenge

The ocelot (Leopardus pardalis) is included in list of wild felid species protected by CITES and is part of conservation strategies that necessarily involve the use of assisted reproduction techniques, which requires practical and minimally invasive techniques of high reproducibility that permit the study of animal reproductive physiology. The objective of this study was to compare and validate two commercial assays: ImmuChem Double Antibody Corticosterone 125I RIA from ICN Biomedicals, Costa Mesa, CA, USA; and Coat-a-Count Cortisol 125I RIA from DPC, Los Angeles, CA, USA, for assessment of fecal glucocorticoid metabolites in ocelots submitted to ACTH (adrenocorticotropic hormone) challenge. Fecal samples were collected from five ocelots kept at the Brazilian Center of Neotropical Felines, Associação Mata Ciliar, São Paulo, Brazil, and one of the animals was chosen as a negative control. The experiment was conducted over a period of 9 days. On day 0, a total dose of 100 IU ACTH was administered intramuscularly. Immediately after collection the samples were stored at 20C in labeled plastic bags. The hormone metabolites were subsequently extracted and assayed using the two commercial kits. Previously it was performed a trial with the DPC kit to check the best extraction method for hormones metabolites. Data were analyzed with the SAS program for Windows V8 and reported as means ± SEM. The Schwarzenberger extraction method was slightly better when compared with the Wasser extraction method (103,334.56 ± 19,010.37ng/g of wet feces and 59,223.61 ± 12,725.36ng/g of wet feces respectively; P=0,0657). The ICN kit detected an increase in glucocorticoid metabolite concentrations in a more reliable manner. Metabolite concentrations (ng/g wet feces) on day 0 and day 1 were 66,956.28 ± 36,786.93 and 92,991.19 ± 28,555.63 for the DPC kit, and 205,483.32 ± 83,811.32 and 814,578.75 ± 292,150.47 for the ICN kit, respectively. The limit of detection for the ICN kit was 7.7 ng/mL for 100% B/Bo (25ng/mL for 88%B/Bo) and for the DPC kit it was 0.2ug/dL for 90.95% B/Bo (1ug/dL for 81.27% B/Bo). In conclusion it was confirmed that the Schwarzenberger extraction method and the ICN kit are superior for extracting and measuring fecal glucocorticoid metabolites in ocelot fecal samples.

Röster från kriget : en etnologisk studie av brevdialoger mellan frontsoldater och deras familjer 1941–1944

Avhandlingen handlar om förbindelsen mellan svenskspråkiga soldater och deras familjer under fortsättningskriget. Utgående från ett omfattande brevmaterial analyseras brevkontaktens betydelser för dem som länge tvingades leva åtskilda under en livshotande tid. I arbetet studeras de personliga erfarenheterna av kriget och krigsvardagen så som de framställdes i brevsamtalen mellan avhandlingens fem soldater och deras närmaste. Mellan fronten och hemmafronten uppstod förutom det rumsliga avståndet också ett erfarenhetsmässigt avstånd till följd av att livet vid fronten skiljde sig markant från det civila och fredstida. För att undvika främlingskap var det viktigt att hålla en tät kontakt per brev och att regelbundet hålla mottagaren underrättad om det egna livet. I studien behandlas olika handlingsstrategier som skribenterna tillgrep i sin vardag och inom ramen för brevsamtalet för att upprätthålla den nära relationen och det gemensamma livet avståndet och separationen till trots. Krigsfronten och hemmafronten bör därför inte betraktas som fullständigt separata sfärer. Det förekom överskridanden på många plan och dessutom medvetna försök att väva samman livet vid de båda fronterna. Brevskrivandet hade också en terapeutisk funktion och betydande roll i soldaternas försök att klara av krigets påfrestningar. Av denna orsak fick även svåra erfarenheter utrymme i bre¬ven. Soldaterna behövde stödet från sina närmaste, men för att inte belasta och oroa familjen orimligt måste de i varierande grad förtiga eller nedtona krigets destruktiva verklighet. Materialet visar att ämnen med kopplingar till det civila övervägde i breven från fronten. Mest skrev man om sådant parterna delade och kunde förstå. Under krigets ovissa tid blev det nödvändigt att försöka hålla fast vid någon form av normalitet. Brevet blev därför framför allt ett rum för det trygga, civila och normala – ett rum där det tidigare levde kvar och där samhörigheten och familjelivet aktivt upprätthölls. -------------------------------------------------------------------------------------------------------------- Sotavuosina, jolloin suuri osa Suomen perheistä joutui pitkäksi aikaa erilleen, kirje jäi käytännössä ainoaksi mahdolliseksi viestintäkeinoksi. Väitöskirjassani tutkin viiden sotilaan ja heidän perheidensä välistä yhteydenpitoa jatkosodan aikana. Laajan kirjeaineiston avulla tarkastelen kirjeenvaihdon merkityksiä ja tehtäviä erossaolon aikana ja omaa elämää uhkaavassa sodan poikkeustilassa. Rintaman ja kotirintaman vastavuoroisen kirjeenvaihdon tarkan lähiluennan avulla analysoin sota-aikaa ja sen kokemista kokonaisvaltaisesta näkökulmasta. Tutkimus osoittaa kuinka jatkuva yhteys perheisiin oli rintamamiehille tärkeätä mm. henkisen selviytymisen kannalta sekä läheisten suhteiden ylläpitämiseksi. Koska kirjeenvaihto oli tärkeä henkireikä, kirjeet sisältävät raskaita kokemuksia sekä kertomuksia taisteluista, partiotehtävistä, kuolemasta, pelosta. Jotta läheiset eivät huolestuisi kohtuuttomasti, kirjeissä kuitenkin yleensä vältettiin kertomasta vaikeista kokemuksista kovin avoimesti. Sotilaiden kirjeet sisältävät pääasiassa kokemuksia ja aiheita, joilla oli monia yhtymäkohtia rauhanaikaiseen ja normaaliin elämään. Kirjeissä kerrottiin arkisista asioista, jotka olivat kirjoittaville osapuolille tuttuja, mikä vahvisti yhteydentunnetta ja vähensi kokemuksellista etäisyyttä. Nykypäivän lukija saattaakin ihmetellä kirjeiden arkipäiväisyyttä, mutta kirje oli sotilaille väylä normaaliin, turvalliseen siviilielämään – tila, jonka kautta he hetkeksi siirtyivät kotiin. Kirjeitse kirjoittajat tukivat toisiaan, loivat tunteen turvallisuudesta, jatkuvuudesta ja normaaliudesta, sekä sisällyttivät toisensa omaan elämäänsä toisaalla. Tutkimus osoittaa kuinka jatkuva ja tiivis yhteydenpito sodan raskaissa olosuhteissa liitti rintaman ja kotirintaman yhteen näiden välissä olevasta kuilusta huolimatta.

Analysis and modelling of chemical looping combustion process with and without oxygen uncoupling

Effective control and limiting of carbon dioxide (CO₂) emissions in energy production are major challenges of science today. Current research activities include the development of new low-cost carbon capture technologies, and among the proposed concepts, chemical combustion (CLC) and chemical looping with oxygen uncoupling (CLOU) have attracted significant attention allowing intrinsic separation of pure CO₂ from a hydrocarbon fuel combustion process with a comparatively small energy penalty. Both CLC and CLOU utilize the well-established fluidized bed technology, but several technical challenges need to be overcome in order to commercialize the processes. Therefore, development of proper modelling and simulation tools is essential for the design, optimization, and scale-up of chemical looping-based combustion systems. The main objective of this work was to analyze the technological feasibility of CLC and CLOU processes at different scales using a computational modelling approach. A onedimensional fluidized bed model frame was constructed and applied for simulations of CLC and CLOU systems consisting of interconnected fluidized bed reactors. The model is based on the conservation of mass and energy, and semi-empirical correlations are used to describe the hydrodynamics, chemical reactions, and transfer of heat in the reactors. Another objective was to evaluate the viability of chemical looping-based energy production, and a flow sheet model representing a CLC-integrated steam power plant was developed. The 1D model frame was succesfully validated based on the operation of a 150 kWth laboratory-sized CLC unit fed by methane. By following certain scale-up criteria, a conceptual design for a CLC reactor system at a pre-commercial scale of 100 MWth was created, after which the validated model was used to predict the performance of the system. As a result, further understanding of the parameters affecting the operation of a large-scale CLC process was acquired, which will be useful for the practical design work in the future. The integration of the reactor system and steam turbine cycle for power production was studied resulting in a suggested plant layout including a CLC boiler system, a simple heat recovery setup, and an integrated steam cycle with a three pressure level steam turbine. Possible operational regions of a CLOU reactor system fed by bituminous coal were determined via mass, energy, and exergy balance analysis. Finally, the 1D fluidized bed model was modified suitable for CLOU, and the performance of a hypothetical 500 MWth CLOU fuel reactor was evaluated by extensive case simulations.

The Brazilian investment in science and technology

An analysis of Brazilian federal expenditures in science and technology is presented is this study. The 1990-1999 data were compiled from records provided by two federal agencies (MCT and CNPq) responsible for managing most of the national budget related to these activities. The results indicate that the federal investments in Brazilian science and technology stagnated during the last decade (US$ 2.32 billion in 1990, US$ 2.39 billion in 1996, and US$ 2.36 billion in 1999). In contrast, a great increase in private investments in research was acknowledged both by industry and by the government during the same period, from US$ 2.12 to US$ 4.64 billion. However, this investment did not result in an increase in invention patents granted to residents (492 in 1990 and only 232 in 1997) or in a reduction of patent costs. Despite this unfavorable scenario, the number of graduate programs in the country has increased two-fold in the last decade and the contribution of Brazilians to the database of the Institute for Scientific Information has increased 4.7-fold from 1990 (2,725 scientific publications) to 2000 (12,686 scientific publications). Unstable federal resources for science, together with the poor returns of private resources in terms of developing new technologies, may jeopardize the future of Brazilian technological development.

A randomized, double-blind, and placebo-controlled study with tranexamic acid of bleeding and fibrinolytic activity after primary coronary artery bypass grafting

Cardiopulmonary bypass is frequently associated with excessive blood loss. Platelet dysfunction is the main cause of non-surgical bleeding after open-heart surgery. We randomized 65 patients in a double-blind fashion to receive tranexamic acid or placebo in order to determine whether antifibrinolytic therapy reduces chest tube drainage. The tranexamic acid group received an intravenous loading dose of 10 mg/kg, before the skin incision, followed by a continuous infusion of 1 mg kg-1 h-1 for 5 h. The placebo group received a bolus of normal saline solution and continuous infusion of normal saline for 5 h. Postoperative bleeding and fibrinolytic activity were assessed. Hematologic data, convulsive seizures, allogeneic transfusion, occurrence of myocardial infarction, mortality, allergic reactions, postoperative renal insufficiency, and reopening rate were also evaluated. The placebo group had a greater postoperative blood loss (median (25th to 75th percentile) 12 h after surgery (540 (350-750) vs 300 (250-455) mL, P = 0.001). The placebo group also had greater blood loss 24 h after surgery (800 (520-1050) vs 500 (415-725) mL, P = 0.008). There was a significant increase in plasma D-dimer levels after coronary artery bypass grafting only in patients of the placebo group, whereas no significant changes were observed in the group treated with tranexamic acid. The D-dimer levels were 1057 (1025-1100) µg/L in the placebo group and 520 (435-837) µg/L in the tranexamic acid group (P = 0.01). We conclude that tranexamic acid effectively reduces postoperative bleeding and fibrinolysis in patients undergoing first-time coronary artery bypass grafting compared to placebo.