708 research outputs found

    UTJECAJ UVJETA POSTUPKA DOBIVANJA MLJEVENE TROSKE TALJENJEM UGLJENA U VISOKOJ PEĆI UZ UPORABU GEOPOLIMERA

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    In this study, the material characterization of Vietnamese ground coal slag and ground granulated blast furnace slag (GGBFS), such as particle size distribution, chemical composition, bulk density and particle density are shown. The geopolymer specimens were prepared by mixing an 80 m/m% mass of solid materials (ground coal slag and GGBFS in a different ratio) with 20 m/m % of a 10M NaOH alkaline activator. A systematic experimental series was carried out in order to optimize the preparation process. In that series, the heat curing temperature was 60°C for 6 hours, and then selected specimens were heat treated at a high temperature (1000 °C) for 1 hour. After 7 days of ageing, the physical properties of the geopolymer (compressive strength, specimen density) were measured. Also, after 180 days of ageing, the pH values of water in the geopolymer leaching preparation were determined. The results show that the geopolymer can be used for refractory applications due to its good heat resistance properties. However, geopolymers that were heated at 1000 °C had lower compressive strength, specimen density and pH values of water containing the geopolymer than those that were cured at 60 °C.U ovome istraživanju donose se obilježja vijetnamskih granulata ugljene troske i troske željezne rude na osnovi njihove veličine, kemijskoga sastava i gustoće. Uzorci geopolimera pripremljeni su miješanjem 80 % m/m (mase otopljenoga / masa otopine) ugljene i željezne troske (u različitim omjerima) s 20 % m/m 10M NaOH kao alkalnoga aktivatora. Sustavnim serijama eksperimenata optimiziran je postupak pripreme, pri čemu je temperatura iznosila 60 °C tijekom 6 sati, nakon čega su odabrani uzorci zagrijavani 1 sat na 1000 °C. Nakon sljedećih 7 dana izmjerena su fizička svojstva geopolimera (tlačna čvrstoća, gustoća). Zatim je poslije 180 dana određena pH-vrijednost vode korištene u postupku ispiranja geopolimera. Rezultati su pokazali kako geopolimeri mogu biti korišteni za namjene u vatrostalnim uvjetima zahvaljujući toplinskim svojstvima. Također, geopolimeri koji su zagrijavani na 1000 °C imaju niže vrijednosti tlačne čvrstoće, gustoće i pH-vrijednosti vode u njima od onih koji su grijani na 60 °C

    Analysis of the Expression of Repetitive DNA Elements in Osteosarcoma

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    Osteosarcoma (OS) is a rare malignant bone tumor. It affects mostly young persons and has poor outcome with the present treatment. No improvement was observed since the introduction of chemotherapy. The better understanding of osteosarcoma development could indicate better management strategy. Repetitive DNA elements were found to play a role in cancer mechanism especially in epithelial tumors but not yet analyzed in osteosarcoma. We conducted the study to analyse the expression profile of repetitive elements (RE) in osteosarcoma. Methods: Fresh bone paired (tumor and normal bone) samples were obtained from excised parts of tumors of 18 patients with osteosarcoma. We performed sequencing of RNA extracted from 36 samples (18 tumor tissues and 18 normal bone for controls), mapped raw reads to the human genome and identified the REs. EdgeR package was used to analyse the difference in expression of REs between osteosarcoma and normal bone. Results: 82 REs were found differentially expressed (FDR < 0.05) between osteosarcoma and normal bone. Out of all significantly changed REs, 35 were upregulated and 47 were downregulated. HERVs (THE1C-int, LTR5, MER57F and MER87B) and satellite elements (HSATII, ALR-alpha) were the most significantly differential expressed elements between osteosarcoma and normal tissues. These results suggest significant impact of REs in the osteosarcoma. The role of REs should be further studied to understand the mechanism they have in the genesis of osteosarcoma

    Environmental allergen reduction in asthma management: an overview

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    Asthma is a prevalent non-communicable disease that affects both children and adults. Many patients with severe, uncontrolled asthma could not achieve total control despite using anti-asthmatic drugs. There is increasing evidence that allergy to environmental allergens, including both indoor and outdoor allergens, is associated with asthma symptoms and severe asthma. Frequently reported sensitized allergens were dust mites, cockroaches, grass pollens, molds, pets, and rodents in allergic asthma patients, although the patterns of widespread allergens differed from each country. Allergen avoidance is the cornerstone of asthma management, especially in sensitized subjects. This review summarizes environmental allergen avoidance and clarifies their effects on asthma control. Despite contrasting results about the impact of allergen exposure reduction on asthma control, several studies supported the beneficial effects of reducing asthma-related symptoms or risk of exacerbations as a nondrug therapy. Identifying environmental allergens is helpful for asthma patients, and further studies on clinically effective avoidance methods are required

    Detection of co-infection and recombination cases with Omicron and local Delta variants of SARS-CoV-2 in Vietnam

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    The first nationwide outbreak of COVID-19 in Vietnam started in late April 2021 and was caused almost exclusively by a single Delta lineage, AY.57. In early 2022, multiple Omicron variants co-circulated with Delta variants and quickly became dominant. The co-circulation of Delta and Omicron happened leading to possibility of co-infection and recombination events which can be revealed by viral genomic data. From January to October 2022, a total of 1028 viral RNA samples out of 4852 positive samples (Ct < 30) were sequenced by the long pooled amplicons method on Illumina platforms. All sequencing data was analysed by the workflow for SARS-CoV-2 on CLC genomics workbench and Illumina Dragen Covid application. Among those sequenced samples, we detected a case of Delta AY.57/Omicron BA.1 co-infection and two cases of infection with Delta AY.57/Omicron BA.2 recombinants which were nearly identical and had different epidemiological characteristics. Since the AY.57 lineage circulated almost exclusively in Vietnam, these results strongly suggest domestic events of co-infection and recombination. These findings highlight the strengths of genomic surveillance in monitoring the circulating variants in the community enabling rapid identification of viral changes that may affect viral properties and evolutionary events

    Leukotriene A4 Hydrolase Genotype and HIV Infection Influence Intracerebral Inflammation and Survival From Tuberculous Meningitis.

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    BACKGROUND: Tuberculous meningitis (TBM) is the most devastating form of tuberculosis, yet very little is known about the pathophysiology. We hypothesized that the genotype of leukotriene A4 hydrolase (encoded by LTA4H), which determines inflammatory eicosanoid expression, influences intracerebral inflammation, and predicts survival from TBM. METHODS: We characterized the pretreatment clinical and intracerebral inflammatory phenotype and 9-month survival of 764 adults with TBM. All were genotyped for single-nucleotide polymorphism rs17525495, and inflammatory phenotype was defined by cerebrospinal fluid (CSF) leukocyte and cytokine concentrations. RESULTS: LTA4H genotype predicted survival of human immunodeficiency virus (HIV)-uninfected patients, with TT-genotype patients significantly more likely to survive TBM than CC-genotype patients, according to Cox regression analysis (univariate P = .040 and multivariable P = .037). HIV-uninfected, TT-genotype patients had high CSF proinflammatory cytokine concentrations, with intermediate and lower concentrations in those with CT and CC genotypes. Increased CSF cytokine concentrations correlated with more-severe disease, but patients with low CSF leukocytes and cytokine concentrations were more likely to die from TBM. HIV infection independently predicted death due to TBM (hazard ratio, 3.94; 95% confidence interval, 2.79-5.56) and was associated with globally increased CSF cytokine concentrations, independent of LTA4H genotype. CONCLUSIONS: LTA4H genotype and HIV infection influence pretreatment inflammatory phenotype and survival from TBM. LTA4H genotype may predict adjunctive corticosteroid responsiveness in HIV-uninfected individuals

    Quel rôle peut-on imputer aux banques à charte canadiennes dans la transmission des chocs monétaires des années quatre-vingt?

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    Cette recherche s’inscrit dans la foulée de nombreux travaux entrepris suite aux publications de Bernanke et Blinder (1988, 1992) ayant remis à l’avant-plan le rôle joué par le système bancaire dans la transmission de la politique monétaire. Nous proposons d’examiner la dynamique inhérente à certains postes du bilan des banques à charte canadiennes suite aux mouvement des principaux taux d’intérêt, habituellement jugés révélateurs des conditions monétaires du moment. Pour ce faire, nous avons recours à un modèle VAR hebdomadaire comportant à la fois, des éléments de l’actif et du passif des banques ainsi que les taux de rendement associés à divers instruments financiers. Cependant, dans le but de bien encadrer cette analyse, nous développons un modèle formel du comportement d’une banque où les seuls changements aux postes de son bilan suite aux mouvements de taux d’intérêt sont dictés par des ajustements de portefeuille visant à tirer avantage des écarts se creusant entre ceux-ci. Ce modèle théorique est soumis aux variations de taux d’intérêt issues du modèle empirique VAR. Les mouvements observés aux postes du bilan de cette banque « témoin » fournissent un guide utile permettant d’interpréter de façon éclairée les résultats empiriques obtenus. À cet égard, l’exercice proposé montre qu’il est possible d’établir un parallèle assez étroit entre l’évolution des postes du bilan de la banque hypothétique et celle captée par le modèle VAR et ainsi apporte un certain support à l’approche traditionnelle sur le rôle joué par les banques dans la transmission des chocs monétaires.This paper can be seen as a contribution to a growing literature initiated by Bernanke and Blinder (1988, 1992) which have examined the role played by the banking system in the transmission of monetary policy. We propose to study the dynamic behaviour of the balance sheet of Canadian chartered banks following a shock to some key interest rates which are good indicators of the prevailing monetary conditions. More specifically, we estimate a weekly VAR model which comprises key asset and liabilities elements as well as rates of return on major financial instruments. However, to guide this empirical inquiry, we set up a model of a representative bank which adjusts its balance sheet elements according to the interest rate spreads arising in the financial markets. This theoretical model is then subjected to the same interest rate shocks than those imposed on the VAR model: the adjustments observed in this laboratory will prove quite useful to assess the significance of the empirical results uncovered by the VAR model. Overall, we find that both approaches give rise to quite similar dynamic responses which tends to support the traditional role of the banking sector in the transmission of monetary policy
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