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1.
PLoS One ; 16(10): e0258449, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34705858

RESUMO

The paper examines the interest of the commercial banks' stakeholders in Pillar 3 disclosures and their behaviour during the timing of serious market turbulence. The aim is to discover to which extent current banking regulation supports stakeholders' interest in the information required by regulators to be disclosed. The examined data consists of log files that were pre-processed using web mining techniques and from which were extracted frequent item sets by quarters and evaluated in terms of quantity. The authors have proposed a methodology to evaluate frequent item sets of web parts over a dedicated time. Based on the verification of applied methodology on two commercial banks, the results show that stakeholders' interest in disclosures is highest in the first quarter at each year and after turbulent times in 2009 their interests decreased. Moreover, the results suggest that stakeholders expressed higher interest than in regulatory required Pillar 3 information in the following group of information: Pillar3 related information, Annual reports, Information on Group. Following our results, the paper contributes to cover the gap in the research by analysing Pillar 3 disclosures and their compliance with regulatory requirements, which also increase the interest of the relevant stakeholders to conduce them as an effective market discipline tool.


Assuntos
Revelação
2.
PLoS One ; 16(9): e0256940, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34520453

RESUMO

Fake news is a complex problem that leads to different approaches used to identify them. In our paper, we focus on identifying fake news using its content. The used dataset containing fake and real news was pre-processed using syntactic analysis. Dependency grammar methods were used for the sentences of the dataset and based on them the importance of each word within the sentence was determined. This information about the importance of words in sentences was utilized to create the input vectors for classifications. The paper aims to find out whether it is possible to use the dependency grammar to improve the classification of fake news. We compared these methods with the TfIdf method. The results show that it is possible to use the dependency grammar information with acceptable accuracy for the classification of fake news. An important finding is that the dependency grammar can improve existing techniques. We have improved the traditional TfIdf technique in our experiment.


Assuntos
Mineração de Dados/estatística & dados numéricos , Enganação , Linguística/estatística & dados numéricos , Mídias Sociais/ética , Conjuntos de Dados como Assunto , Humanos
3.
PeerJ Comput Sci ; 7: e624, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34395862

RESUMO

Research of the techniques for effective fake news detection has become very needed and attractive. These techniques have a background in many research disciplines, including morphological analysis. Several researchers stated that simple content-related n-grams and POS tagging had been proven insufficient for fake news classification. However, they did not realise any empirical research results, which could confirm these statements experimentally in the last decade. Considering this contradiction, the main aim of the paper is to experimentally evaluate the potential of the common use of n-grams and POS tags for the correct classification of fake and true news. The dataset of published fake or real news about the current Covid-19 pandemic was pre-processed using morphological analysis. As a result, n-grams of POS tags were prepared and further analysed. Three techniques based on POS tags were proposed and applied to different groups of n-grams in the pre-processing phase of fake news detection. The n-gram size was examined as the first. Subsequently, the most suitable depth of the decision trees for sufficient generalization was scoped. Finally, the performance measures of models based on the proposed techniques were compared with the standardised reference TF-IDF technique. The performance measures of the model like accuracy, precision, recall and f1-score are considered, together with the 10-fold cross-validation technique. Simultaneously, the question, whether the TF-IDF technique can be improved using POS tags was researched in detail. The results showed that the newly proposed techniques are comparable with the traditional TF-IDF technique. At the same time, it can be stated that the morphological analysis can improve the baseline TF-IDF technique. As a result, the performance measures of the model, precision for fake news and recall for real news, were statistically significantly improved.

4.
Plant Cell Rep ; 36(1): 49-60, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27655251

RESUMO

KEY MESSAGE: Micropropagation protocol of transgenic lettuce bearing S-, M- and L-HBsAg was developed for increased production of uniformised material for oral vaccine preparation. Effective manufacturing of plant-based biopharmaceuticals, including oral vaccines, depends on sufficient content of a protein of interest in the initial material and its efficient conversion into an administrable formulation. However, stable production of plants with a uniformised antigen content is equally important for reproducible processing. This can be provided by micropropagation techniques. Here, we present a protocol for micropropagation of transgenic lettuce lines bearing HBV surface antigens: S-, M- and L-HBsAg. These were multiplied through axillary buds to avoid the risk of somaclonal variation. Micropropagation effectiveness reached 3.5-5.7 per passage, which implies potential production of up to 6600 plant clones within a maximum 5 months. Multiplication and rooting rates were statistically homogenous for most transgenic and control plants. For most lines, more than 90 % of clones obtained via in vitro micropropagation had HBsAg content as high as reference plants directly developed from seeds. Clones were also several times more uniform in HBsAg expression. Variation coefficients of HBsAg content did not exceed 10 % for approximately 40-85 % of clones, or reached a maximum 20 % for 90 % of all clones. Tissue culture did not affect total and leaf biomass yields. Seed production for clones was decreased insignificantly and did not impact progeny condition. Micropropagation facilitates a substantial increase in the production of lettuce plants with high and considerably equalised HBsAg contents. This, together with the previously reported optimisation of plant tissue processing and its long-term stability, constitutes a successive step in manufacturing of a standardised anti-HBV oral vaccine of reliable efficacy.


Assuntos
Antígenos de Superfície da Hepatite B/metabolismo , Lactuca/crescimento & desenvolvimento , Lactuca/genética , Agricultura Molecular/métodos , Técnicas de Cultura de Tecidos/métodos , Plantas Geneticamente Modificadas
5.
Plant Cell Rep ; 35(5): 1209-12, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26905723

RESUMO

KEY MESSAGE: Intramuscularly delivered plant-derived M-HBsAg was compared to S-HBsAg, and as a result elicited specific anti-preS2 antibodies and significantly higher titre of anti-HBs antibodies, together with IgG isotype profile indicating some Th1 polarisation, apart from the main Th2 response. HBV prevalence is still threatening, regardless of prevention programmes using vaccines containing S-HBsAg, supplemented by third-generation vaccines, comprising also M- and L-HBsAg. Plant expression systems offer a cost-effective production option of the antigens. Plant-derived S- and M-HBsAg, intramuscularly delivered to mice, elicited anti-HBs antibodies several times higher than high responsiveness threshold titre. M-HBsAg induced stronger response of anti-HBs and also specific anti-preS2 antibodies. IgG isotype profiles indicated mainly Th2 response, yet Th1 polarisation was also pointed out, in some larger extent for M-HBsAg. These results correspond to research on CHO-derived M-HBsAg vs. commercial vaccines based on S-HBsAg and support potency of plant-derived antigens as alternative injection vaccines.


Assuntos
Anticorpos Anti-Hepatite B/sangue , Antígenos de Superfície da Hepatite B/imunologia , Vacinas contra Hepatite B/administração & dosagem , Vírus da Hepatite B/imunologia , Hepatite B/prevenção & controle , Animais , Injeções Intramusculares , Camundongos
6.
Plant Cell Rep ; 31(3): 585-95, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22246107

RESUMO

Current immunisation programmes against hepatitis B virus (HBV) increasingly often involve novel tri-component vaccines containing-together with the small (S-HBsAg)-also medium and large surface antigens of HBV (M- and L-HBsAg). Plants producing all HBsAg proteins can be a source of components for a potential oral 'triple' anti-HBV vaccine. The objective of the presented research was to study the potential of M/L-HBsAg expression in leaf tissue and conditions of its processing for a prototype oral vaccine. Tobacco and lettuce carrying M- or L-HBsAg genes and resistant to the herbicide glufosinate were engineered and integration of the transgenes was verified by PCR and Southern hybridizations. M- and L-HBsAg expression was confirmed by Western blot and assayed by ELISA at the level of micrograms per g of fresh weight. The antigens displayed a common S domain and characteristic domains preS2 and preS1 and were assembled into virus-like particles (VLPs). Leaf tissues containing M- and L-HBsAg were lyophilised to produce a starting material of an orally administered vaccine formula. The antigens were distinctly sensitive to freeze-drying conditions and storage temperature, in the aspect of stability of S and preS domains and formation of multimeric particles. Efficiency of lyophilisation and storage depended also on the initial antigen content in plant tissue, yet M-HBsAg appeared to be approximately 1.5-2 times more stable than L-HBsAg. The results of the study provide indications concerning the preparation of two other constituents, next to S-HBsAg, for a plant-derived prototype oral tri-component vaccine against hepatitis B.


Assuntos
Antígenos de Superfície da Hepatite B/metabolismo , Vacinas contra Hepatite B/administração & dosagem , Vírus da Hepatite B/imunologia , Hepatite B/prevenção & controle , Lactuca/metabolismo , Nicotiana/metabolismo , Liofilização , Antígenos de Superfície da Hepatite B/análise , Antígenos de Superfície da Hepatite B/genética , Lactuca/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Preparações de Plantas , Plantas Geneticamente Modificadas , Estabilidade Proteica , Temperatura , Nicotiana/genética
7.
J Appl Genet ; 52(2): 125-36, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21107787

RESUMO

Efficient immunization against hepatitis B virus (HBV) and other pathogens with plant-based oral vaccines requires appropriate plant expressors and the optimization of vaccine compositions and administration protocols. Previous immunization studies were mainly based on a combination of the injection of a small surface antigen of HBV (S-HBsAg) and the feeding with raw tissue containing the antigen, supplemented with an adjuvant, and coming from plants conferring resistance to kanamycin. The objective of this study was to develop a prototype oral vaccine formula suitable for human immunization. Herbicide-resistant lettuce was engineered, stably expressing through progeny generation micrograms of S-HBsAg per g of fresh weight and formed into virus-like particles (VLPs). Lyophilized tissue containing a relatively low, 100-ng VLP-assembled antigen dose, administered only orally to mice with a long, 60-day interval between prime and boost immunizations and without exogenous adjuvant, elicited mucosal and systemic humoral anti-HBs responses at the nominally protective level. Lyophilized tissue was converted into tablets, which preserved S-HBsAg content for at least one year of room temperature storage. The results of the study provide indications on immunization methodology using a durable, efficacious, and convenient plant-derived prototype oral vaccine against hepatitis B.


Assuntos
Antígenos de Superfície da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Hepatite B/prevenção & controle , Lactuca/genética , Proteínas Recombinantes/imunologia , Vacinação , Administração Oral , Aminobutiratos/farmacologia , Animais , Relação Dose-Resposta Imunológica , Retículo Endoplasmático/ultraestrutura , Retículo Endoplasmático/virologia , Fezes/química , Liofilização , Antígenos de Superfície da Hepatite B/biossíntese , Vacinas contra Hepatite B/administração & dosagem , Vírus da Hepatite B/ultraestrutura , Resistência a Herbicidas , Herbicidas/farmacologia , Humanos , Imunidade Humoral , Imunoglobulina A Secretora/sangue , Lactuca/imunologia , Lactuca/metabolismo , Lactuca/virologia , Camundongos , Camundongos Endogâmicos BALB C , Folhas de Planta/imunologia , Folhas de Planta/ultraestrutura , Folhas de Planta/virologia , Plantas Geneticamente Modificadas/imunologia , Proteínas Recombinantes/biossíntese , Vacinas de Plantas Comestíveis/administração & dosagem
8.
Arch Immunol Ther Exp (Warsz) ; 58(2): 143-51, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20165988

RESUMO

Mucosal immunity elicited by plant-based and other orally administered vaccines can serve as the first line of defense against most pathogens infecting through mucosal surfaces, but it is also considered for systemic immunity against blood-borne diseases such as hepatitis B (HB). Previous oral immunization trials based on multiple administration of high doses of HBs antigen elicited an immune response; however, a reproducible and long-lasting immunization protocol was difficult to design. The objective of this study was to evaluate the effect of dose and timing of orally delivered alum-adsorbed antigen on the magnitude of the anti-HBs humoral response. Mice were immunized orally by gavage intubation or parenterally by intramuscular injection three times, once every 2 weeks, with doses of 5, 50, or 500 ng alum-adjuvanted HBsAg. A low dose (10 ng) of HBsAg was orally administered three times in different time intervals: 2, 4, 6, and 8 weeks. The three consecutive 5-ng oral doses of the antigen induced immune response at the protective level (>or=10 mIU/ml), significantly higher than the reaction elicited by three 50 or 500 ng doses. In contrast, intramuscular delivery of these doses did not differ significantly; however, they induced a five to six times higher immune response than oral immunization. The 8-week period between each of the three oral immunizations appeared to be favorable to the anti-HBs humoral responses compared with the shorter schedules. The results presented here clearly identify the importance of low doses of antigen administered orally in extended intervals for a significantly higher anti-HBs response. This finding provides some indications concerning the strategy of orally administered vaccines, including plant-based ones.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Compostos de Alúmen/administração & dosagem , Antígenos de Superfície da Hepatite B/administração & dosagem , Vacinas contra Hepatite B/administração & dosagem , Imunidade Humoral/efeitos dos fármacos , Administração Oral , Animais , Relação Dose-Resposta a Droga , Feminino , Anticorpos Anti-Hepatite B/sangue , Esquemas de Imunização , Injeções Intramusculares , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes/administração & dosagem , Fatores de Tempo , Vacinas Sintéticas/administração & dosagem
9.
J Appl Genet ; 47(4): 309-18, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17132895

RESUMO

The idea of an oral vaccine administered as a portion of plant tissue requires a high level of antigen production. An improved protocol for the induction of transgenic yellow lupin calli or tumours, reaching 44% of transformation rate, is presented here. It has been developed by using the nptII marker gene and the uidA reporter gene as well as various Agrobacterium strains and plant explants. This method of seedling and hypocotyl transformation was applied to raise calli or tumours producing a small surface antigen of Hepatitis B Virus (S-HBsAg). Lupin tissue lines were long-term cultured on selection media maintaining the growth rate and high expression level of the native form of S-HBs, up to 6 microg per g of fresh tissue.


Assuntos
Antígenos de Superfície da Hepatite B/biossíntese , Lupinus/genética , Plantas Geneticamente Modificadas , Rhizobium/genética , Técnicas de Cultura de Tecidos , Transformação Genética , Proliferação de Células , Antígenos de Superfície da Hepatite B/genética , Lupinus/crescimento & desenvolvimento , Lupinus/metabolismo , Rhizobium/metabolismo
10.
J Appl Genet ; 46(2): 139-47, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15876681

RESUMO

An Agrobacterium-mediated transformation method of pea has been developed for several edible and fodder cultivars of pea (Pisum sativum L.), characterized previously in their potential for regeneration via organogenesis. The most appropriate explant, which was susceptible to Agrobacterium infection and capable of regenerating transgenic plants, turned out to be a slice of an immature embryo, including the embryo axis and the basal part of a cotyledon. Three hypervirulent strains of A. tumefaciens were tested: AgL0, AgL1 and EHA105. Each carried the binary vector pP35SGIB containing the uid gene, with an intron under control of the 35S promoter, and the bar gene conferring resistance to phosphinotricin. Strain AgL0 was found to be efficient for the majority of cultivars, followed by AgL1 and EHA105. Transformation efficiency varied from 0.7 to 4.1%, depending on cultivar and Agrobacterium strain. The transformation efficiency of particular pea cultivars did not clearly correspond to their regeneration capacity, which--although indispensable--was not a critical parameter of successful transformation. The presence of integrated genes in pea genomic DNA was detected by the PCR. T-DNA was stably transmitted to the progeny, as it was confirmed by Southern hybridization. The activity of introduced genes was analysed by the histochemical GUS assay and by painting leaves or by spraying transgenic plants with the herbicide Basta.


Assuntos
Pisum sativum/crescimento & desenvolvimento , Pisum sativum/genética , Plantas Geneticamente Modificadas , Rhizobium/fisiologia , Transformação Genética , Aminobutiratos/farmacologia , Biotecnologia/métodos , Cruzamento , DNA Bacteriano/análise , Resistência a Medicamentos , Herbicidas/farmacologia , Pisum sativum/microbiologia , Raízes de Plantas/microbiologia , Plantas Comestíveis , Transgenes
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