Synthesis of new sugar derivatives containing an α, β-unsaturated carbonyl system in their structure and biological evaluation

Tese de doutoramento, Química (Química Orgânica), Universidade de Lisboa, Faculdade de Ciências, 2011This PhD research work was focused on the synthesis and uses of bicyclic carbohydrate lactones, in the context of the access to new sugar derivatives containing an α,β- unsaturated carbonyl function. These molecular targets, chosen for the intrinsic bioactivity associated to the conjugated carbonyl system, were synthesized and submitted to biological evaluation, particularly their effect towards fungi and bacteria. Moreover, the inclusion of conjugated carbonyl systems in carbohydrates provides suitable templates for further derivatization, to which a variety of reactions may be applied. Three types of bicyclic sugar lactones were investigated: furanose C-C-linked butenolides (compounds type I), pyranose-fused butenolides, including S- or NHanalogues (compounds type II-IV), and carboxymethyl glycoside-derived lactones (CMGLs, compounds type V). The access to butenolide containing-sugars was explored. The synthetic methodology was based on the Wittig olefination of easily prepared 3- or 5-keto sugars and spontaneous intramolecular lactonization of the intermediate g-hydroxy α,β-unsaturated esters. In the case of the bicyclic fused derivatives, furanos-3-uloses containing acid labile 5-O or 5,6-di-O-protecting groups were used as precursors and converted into the corresponding (Z)- or (E)-3-C-(ethoxycarbonyl)methylene furanoses. Further acidmediated hydrolysis made possible their isomerization to the pyranose ring and concomitant intramolecular transesterification leading directly to the target compounds in good overall yields. Such bicyclic systems featured the butenolide moiety annelated at C-2-C-3 (compounds type II) or at C-3-C-4 of the sugar backbone, depending on the stereochemistry of the C3-C3’double bond. The introduction of a sulfur function at C-5 of the furanoid 3-C-α,β-unsaturated esters, widened the scope of this methodology to thiosugar analogues of type III. When this approach was applied to related 5-azido furanoid esters aiming at imino sugar-based molecules of type IV, different carbohydrate derivatives comprising both an amide functionality and an α,b-unsaturated carbonyl system were obtained. The (E)- and (Z)-3-C-(ethoxycarbonyl)methylene 5- amino furanoses were converted to a furanose-fused α,β-unsaturated δ-lactam and to a butenolide-containing N-ethylformamide, respectively. Moreover, the hydrolysis of the 1,2-O-isopropylidene group of the (Z)-5-azido furanose precursor, followed by azide reduction, provided a 2-keto iminopyranose, which led to the 1,2-dihydropyridin-3-one system upon acetylation. CMGLs (compounds type V) were used as precursors for 3-enopyranosid-2-uloses (compounds type VI). The opening of the lactone moiety by amines provided tri-Oacylated 2-hydroxy pyranosides which by oxidation/elimination generated the enone system. Further Wittig olefination afforded 2-C-branched-chain conjugated dienepyranosides (compounds type VII). Glycosides bearing a propargyl moiety were engaged in “click” chemistry reactions leading to the corresponding 1,2,3-triazoles (compounds type VIII-IX). Among the molecular targets obtained, the furanose-linked butenolides, the pyranosefused butenolides, the conjugated carbonyl sugar derivatives synthesized from CMGLs and the triazole-containing glycosides were submitted to antimicrobial activity assays. The butenolide-containing sugars did not show satisfactory antibacterial or antifungal activities. Such weak effect is probably due to the presence of a quaternary β-carbon in the conjugated system of these molecules, which is specially hindered in the fused systems, reducing their Michael acceptor ability. In contrast, significant efficacy was observed for 3-enopyranosid-2-uloses and conjugated diene pyranosides. In particular, (N-dodecylcarbamoyl)methyl enulosides displayed strong and very strong activities against some of the pathogen microbes tested, being in some cases similar to those of the standard antibiotics. The α-enuloside exhibited very strong effect towards Bacillus cereus and Bacillus subtillis and strong activity against Enterococcus faecalis and the fungal pathogen Penicillium aurantiogriseum. The β-anomer presented a very strong inhibitory effect against the fungi Aspergillus niger and Penicillium aurantiogriseum. Dienepyranosides exhibited a strong activity selectively towards Enterococcus faecalis. Triazole derivatives were virtually ineffective. Three of the bioactive compounds, including the most active one, i.e. the α-(N-dodecylcarbamoyl)methyl enuloside, showed low acute toxicity in eukaryotic hepatoma cells.O trabalho desenvolvido no âmbito deste Doutoramento centrou-se na síntese e no uso de biciclolactonas glicídicas com o objectivo de se obterem novos derivados de açúcares contendo um sistema carbonílico α,β-insaturado na sua estrutura. Estes alvos moleculares foram sintetizados no sentido de se avaliarem posteriormente as suas propriedades biológicas, nomeadamente a nível de actividade antifúngica e antibacteriana. O sistema carbonílico α,β-insaturado é frequentemente encontrado em produtos naturais e de síntese que possuem uma variedade de actividades biológicas. A bioactividade exibida por estes compostos está geralmente associada à capacidade da função conjugada para reagir segundo adição de Michael com nucleófilos existentes em proteínas. Em particular, derivados de açúcares contendo lactonas α,β-insaturadas foram descritos como fungicidas ou como insecticidas potentes. Por outro lado, a inclusão destas unidades em carbo-hidratos conduz a moléculas funcionalizadas que poderão ser úteis para posterior derivatização, devido à reactividade do sistema conjugado. As moléculas-alvo tiveram como base três tipos de lactonas bicíclicas (Fig. 1): butenolidas ligadas a anéis de furanose (compostos tipo I), butenolidas fundidas a anéis de pyranose, incluindo tio- e iminoaçúcares análogos (compostos tipo II-IV), e lactonas derivadas de glicósidos de carboximetilo (compostos tipo V). A síntese de açúcares contendo butenolidas foi desenvolvida e implementada uma metodologia que envolveu a olefinação de Wittig de 3- ou 5-cetoaçúcares e a lactonização intramolecular expontânea de intermediários γ-hidroxiésters α,β- insaturados formados. Os 5-cetoaçúcares precursores de butenolidas ligadas a furanoses foram obtidos por meio de oxidação selectiva do grupo hidroxilo secundário de 5,6- dióis derivados de 1,2-O-isopropilideno-α-D-glucofuranose e/ou -alofuranose (1-4, Esquema 1). O oxidante utilizado foi o sistema Bu2OSn/NBS (N-bromosuccinimida), dando origem às α-hidroxicetonas desejadas 5-8 com bons rendimentos. A estereoselectividade da reacção de Wittig subsequente com [(etoxicarbonil)metileno]trifenilfosforano foi influenciada pela configuração do substituinte em C-3. Os derivados com configuração xilo 5 e 6 originaram apenas γ- hidroxiésteres insaturados (9, 10) com estereoquímica (Z). Contudo, utilizando as α- hidroxicetonas com configuração ribo 7 e 8, a reacção de Wittig foi estereosseletiva para a formação dos (E)-isómeros, cuja transesterificação intramolecular espontânea deu origem às correspondentes lactonas α,β-insaturadas 13 e 14. Os (Z)-isómeros (11 e 12) foram neste caso produtos minoritários da reacção. A estratégia implementada para a síntese de butenolidas fundidas a piranoses (compostos tipo II, Fig. 1) baseou-se na olefinação de Wittig de derivados 1,2-Oisopropilideno- α-D-pento- ou-hexofuranos-3-ulose, 5-O- ou 5,6-di-O-protegidos com grupos lábeis em meio ácido, seguida de hidrólise ácida. Nestas condições, com a remoção dos grupos protectores, além da reacção de transesterificação intramolecular que leva à formação da lactona, também ocorre isomerização furanose → piranose, conduzindo à síntese das moléculas alvo num só passo. A olefinação de Wittig dos 3-cetoaçúcares 15 e 16 foi estereosselectiva para a formação dos respectivos ésteres (Z)-α,β-insaturados 17a e 18a (Esquema 2). O tratamento de 17a e 18a com a resina ácida Amberlite em refluxo de metanol durante 16 h levou à formação dos compostos-alvo 19 e 21. As condições experimentais de hidrólise de 17a foram optimizadas de modo a reduzir o tempo de reacção para a obtenção do composto bicíclico 19 e também para permitir a formação do correspondente glicósido de metilo 20. A hidrólise de 17a com uma solução aquosa de ácido trifluoroacético (TFA) a 60%, à temperatura ambiente, conduziu ao composto bicíclico desejado 19 em apenas 5 min, com um rendimento de 90%. Utilizando a resina Dowex 50-W, a conversão de 17a em 19 foi completa ao fim de 2 h e, após 16 h de reacção, obteve-se o glicósido de metilo 20. A síntese de um derivado bicíclico regiosselectivamente protegido no grupo hidroxilo primário (composto 25, Esquema 3) foi realizada a partir da monoprotecção selectiva do diol 22 com cloreto de pivaloílo seguida da hidrólise em meio ácido. Analogamente e seguindo a mesma estratégia de síntese, a partir dos ésteres (E)- insaturados 17b e 18b, foram obtidos, com sucesso, os compostos 26-28, nos quais a unidade butenolida está fundida ao anel de piranose nas posições 3 e 4 (Fig. 2). No entanto não se verificou lactonização após remoção do grupo 1,2-isopropilideno do derivado 5,6-di-O-pivaloílado 24, e dos derivados pentofuranóides com configuração erythro, possuindo um grupo pivaloilo em C-5 (29) ou desoxigenado em C-5 (30), nas condições hidrolíticas descritas e obtiveram-se os respectivos dióis 31-33 (Esquema 4). Estes resultados indicam que a fusão de lactonas insaturadas de cinco membros a anéis de furanose é desfavorável, ocorrendo preferencialmente em sistemas de piranose. A eficácia e a conveniência desta metodologia para a obtenção de análogos tioaçúcares e iminoaçúcares (compostos tipo III e IV, Fig. 1), a partir de furanos-3-uloses, foram também investigadas. A estas duas classes de miméticos de carbo-hidratos está frequentemente associada uma variedade de propriedades biológicas, nomeadamente a capacidade de inibição de glicosidases. O interesse neste tipo de estruturas reside também no seu potencial sintético como precursores para novos derivados de tio- e iminoaçúcares. A síntese de butenolidas fundidas a tioaçúcares involveu a introdução de uma função sulfidrílica em C-5 nos derivados (Z)-3-C-(etoxicarbonil)metileno pento- ou hexofuranóides 34 e 35 por meio de substituição nucleófila de um grupo tosilato ou de um triflato, respectivamente, por um grupo tioacetilo (Esquema 5). A remoção dos grupos éster de 36, 37 seguida de hidrólise ácida deu origem aos compostos bicíclicos desejados 38 e 39. A posterior acetilação de 38 e 39 conduziu aos derivados acetilados 40 e 41 e aos tioglicais correspondentes 42 e 43, por eliminação de ácido acético. A acetilação de 39 conduziu maioritariamente ao tioglical 43, o que pode ser explicado pela baixa estabilidade conformacional de 41, devido à presença de um grupo acetoximetilo pseudoaxial. A eliminação em C-1,C-2 não só resulta num sistema conjugado altamente estável, mas no caso de 41 permite a adopção de uma conformação sofá relativamente estável. Para a investigação da síntese de iminoaçúcares do tipo IV foram sintetizados os precursores 5-azido-3-C-(etoxicarbonil)metileno furanoses (44, Esquema 6). A redução do grupo azida do éster (Z)-α,β-insaturado 44a pelo método de Staudinger resultou na respectiva amina 45. A hidrólise de 45 em meio ácido seguida de adição de base para neutralizar o ácido em excesso, resultou no derivado da etilformamida contendo uma butenolida 47. A formação do composto 47 involve o intermediário bicíclico 46, o qual em meio básico é desprotonado no grupo hidroxilo anomérico. O ião resultante rearranja para um ião enolato estabilizado por ressonância, que é protonado em C-2. A hidrólise ácida do grupo 1,2-O-isopropilideno de 44a e posterior redução da função azida do diol 48, de modo a permitir a isomerização 5-aminofuranose/iminopiranose em meio neutro, resultou num 2-cetoiminoaçúcar que por acetilação originou a 1,2-dihidropiridin- 3-ona 49. A redução do grupo azida do (E)-isómero (44b) deu origem à δ- lactama bicíclica 51 por ciclização intramolecular expontânea do δ-aminoéster α,β- insaturado 50. Os derivados 5-aminofuranóides revelaram portanto uma reactividade distinta relativamente aos análogos 5-O e 5-S, que em condições reaccionais semelhantes originaram as butenolidas bicíclicas alvo. As biciclolactonas derivadas de glicósidos de carboximetilo (CMGLs, compostos tipo V, Fig. 1), cuja preparação envolve 2-3 etapas a partir de açúcares livres, foram utilizadas como precursores de cetonas piranóides α,β-insaturadas do tipo hex-3- enopiranosid-2-ulose e de dienopiranósidos conjugados (compostos tipo VI-VII, Fig. 3). A inclusão de uma unidade 1,2,3-triazole, um heterociclo com potencial para conferir bioactividade, para a obtenção de derivados do tipo VIII-IX, foi também investigada. A preparação de cetonas α,β-insaturadas do tipo VI consistiu na abertura nucleófila de CMGLs 52-54 com aminas primárias, seguida de oxidação dos aductos resultantes e eliminação concomitante de ácido acético nas posições 3,4 (Esquema 7). O método de oxidação utilizando o sistema dimetilsulfóxido (DMSO)/anidrido acético (Ac2O) revelou ser o mais eficaz em experiências preliminares e permitiu a obtenção do sistema enona com melhores rendimentos, em relação a outros métodos de oxidação mais suaves. Os 2-hidroxipyranósidos tri-O-acetilados 55-57, 61 com configuração α, conduziram às respectivas enonas 62-64 com bons rendimentos. No entanto, os rendimentos para a oxidação/eliminação dos aductos β (58-60) foram baixos e as respectivas enonas 65-67 demonstraram a sua tendência para a decomposição. Estes resultados devem-se à conformação adoptada por estes compostos, tal como verificado por 1H RMN. Enquanto as enonas 62-64 adoptam uma conformação do tipo envelope OE (sofá), os respectivos anómeros β adoptam uma conformação EO, que é menos estável devido às interacções 1,3-diaxiais. As cetonas α,β-insaturadas foram posteriormente convertidas nos correspondentes dienopiranósidos de cadeia ramificada em C-2 (68-70) por olefinação de Wittig com [(etoxicarbonil)metileno]trifenilfosforano. A configuração (E) da ligação dupla exocíclica foi demonstrada através de NOESY. As reacções de cicloadição dos glicósidos de (N-propargilcarbamoil)metilo 55, 58 e 61 com azoteto de benzilo por meio de um protocolo alternativo de ‘click’ chemistry, tendo como base um catalisador heterogéneo de CuI suportado em Amberlist A-21, deu origem aos triazoles correspondentes 71-73. Os derivados desprotegidos 74-76 foram seguidamente obtidos por desacetilação com NEt3 em metanol e água. A síntese dos compostos do tipo VIII e IX, os quais associam numa molécula um sistema carbonílico conjugado a uma unidade triazole, foi realizada posteriormente (Esquema 8). A oxidação/eliminação de 71 conduziu à 3-enopiranosid-2-ulose 77. O acoplamento do dieno piranósido conjugado 68 com azoteto de benzilo originou o triazole correspondente 78. Entre os alvos moleculares obtidos, os derivados bicíclicos nos quais uma butenolida se encontra ligada a um anel de furanose (compostos tipo I), as butenolidas fundidas a anéis de piranose (compostos tipo II), os derivados piranóides contendo um sistema carbonílico conjugado sintetizados a partir dos precursores CMGLs (compostos tipo VI-VII) e os glicósidos contendo uma unidade triazole (compostos tipo VIII-IX), foram submetidos a testes de actividade antimicrobiana. Foi investigada a inibição de fungos fitopatogénicos e de fungos patogénicos para seres humanos e animais. Foi também feito um estudo sobre a actividade inibidora dos compostos relativamente a bactérias Gram-negativas e Gram-positivas. Os derivados de açúcares contendo butenolidas apresentaram fraca actividade antimicrobiana ou não a exibiram de modo significativo. Estes resultados sugerem uma reduzida aptidão destas moléculas para reagir segundo a adição de Michael, o que se explica pela presença de um C-β quaternário no sistema conjugado, que é estereoquimicamente impedido nas estruturas fundidas. No entanto, os resultados da avaliação biológica das 3-enopiranosid-2-uloses e dos dienopiranósidos de cadeia ramificada revelaram actividades antimicrobianas significativas. Os enulósidos de (N-dodecilcarbamoil)metilo 64 e 67 exibiram actividades fortes ou muito fortes contra alguns dos micróbios testados, demonstrando nalguns casos efeitos inibitórios comparáveis aos dos antibióticos de referência. O enulósido-α (64) revelou actividade muito forte relativamente às bactérias Bacillus cereus e Bacillus subtillis e actividade forte contra Enterococcus faecalis e o fungo Penicillium aurantiogriseum. O anómero-β (67) exibiu um efeito inibitório muito forte contra os fungos Aspergillus niger e Penicillium aurantiogriseum. Os dienopiranósidos conjugados 68-70 revelaram actividade selectiva e forte relativamente a Enterococcus faecalis. Os derivados contendo triazole não demonstraram actividade antimicrobiana significativa. Três dos compostos considerados bioactivos, o α-enulósido de (Ndodecilcarbamoil) metilo 64, e os dienopiranósidos 68 e 69, mostraram ser pouco tóxicos quando submetidos a testes de toxicidade em células eucarióticas hepáticas.FCT (for the support of the project POCI-PPCDT/QUI/59672/2004 and for the PhD grant SFRH/BD/39251/2007), CPU/CRUP (for a joint Portuguese-French research program), MESER and CNR

Linking cardiorespiratory fitness classification criteria to early subclinical atherosclerosis in children

It is unclear if cardiorespiratory fitness (CRF) can be used as a screening tool for premature changes in carotid intima-media thickness (cIMT) in paediatric populations. The purpose of this cross-sectional study was 3-fold: (i) to determine if CRF can be used to screen increased cIMT; (ii) to determine an optimal CRF cut-off to predict increased cIMT; and (iii) to evaluate its ability to predict increased cIMT among children in comparison with existent CRF cut-offs. cIMT was assessed with high-resolution ultrasonography and CRF was determined using a maximal cycle test. Receiver operating characteristic analyses were conducted in boys (n = 211) and girls (n = 202) aged 11-12 years to define the optimal sex-specific CRF cut-off to classify increased cIMT (≥75th percentile). Logistic regression was used to examine the association between the CRF cut-offs with the risk of having an increased cIMT. The optimal CRF cut-offs to predict increased cIMT were 45.81 and 34.46 mL·kg(-1)·min(-1) for boys and girls, respectively. The odds-ratios for having increased cIMT among children who were unfit was up to 2.8 times the odds among those who were fit (95% confidence interval: 1.40-5.53). Considering current CRF cut-offs, only those suggested by Adegboye et al. 2011. (Br. J. Sports Med. 45(9): 722-728) and Boddy et al. 2012 (PLoS One, 7(9): e45755) were significant in predicting increased cIMT. In conclusion, CRF cut-offs (boys: ≤ 45.8; girls: ≤ 34.5 mL·kg(-1)·min(-1)) are associated with thickening of the arterial wall in 11- to 12-year-old children. Low CRF is an important cardiovascular risk factor in children and our data highlight the importance of obtaining an adequate CRF.info:eu-repo/semantics/publishedVersio

Numerical and experimental characterization of Steel - Wood doweled joints under Quasi-Static loading

The objective of this work is to investigate the quasi-static mechanical behaviour of doweltypetimber joints. Therefore, four dowel arrangements were experimentally tested to assurethe stability of a steel-wood joint. The results revealed different behaviour regarding thedistance between dowels and distance to the free edge of the wood member. An approachbased on cohesive zone modelling was adopted to replicate both the ductile and brittle failureobserved in the experiments

Synthesis of sugars embodying conjugated carbonyl systems and related triazole derivatives from carboxymethyl glycoside lactones. Evaluation of their antimicrobial activity and toxicity.

International audienceThe synthesis of a series of pyranoid derivatives comprising a conjugated carbonyl function and related triazole derivatives, structurally suitable for bioactivity evaluation, was achieved in few steps starting from readily available carboxymethyl glycoside lactones (CMGL). 3-Enopyranosid-2-uloses were generated by oxidation/elimination of tri-O-acylated 2-hydroxy pyranosides. Subsequent Wittig olefination provided stereoselectively 2-C-branched-chain conjugated dienepyranosides with (E)-configuration around the exocyclic double bond. A heterogeneous CuI/Amberlyst-catalyzed 'click' chemistry protocol was used to convert glycosides bearing a propargyl moiety into the corresponding 1,2,3-triazoles. These new molecules were screened for their in vitro antibacterial and antifungal activities and those containing conjugated carbonyl systems demonstrated the best efficacy. (N-Dodecylcarbamoyl)methyl enone glycerosides were the most active ones among the enones tested. The α-anomer displayed very strong activities against Bacillus cereus and Bacillus subtilis and strong activity toward Enterococcus faecalis and the fungal pathogen Penicillium aurantiogriseum. The corresponding β-anomer presented a very strong inhibitory effect against two fungal species (Aspergillus niger and P. aurantiogriseum). (N-Dodecyl-/N-propargyl/or N-benzylcarbamoyl)methyl dienepyranosides exhibited selectively a strong activity toward E. faecalis. Further acute toxicity evaluation indicated low toxic effect of the (N-dodecylcarbamoyl)methyl enone glyceroside α-anomer and of the carbamoylmethyl dienepyranosides N-protected with propargyl or benzyl groups

A novel molecular link between HOXA9 and WNT6 in glioblastoma identifies a subgroup of patients with particular poor prognosis

Despite much effort to improve treatments, patients with malignant glioma still present a very poor prognosis that has not changed significantly in the last decades. In this context, it is crucial to better understand glioma pathogenesis to identify new molecular prognostic subgroups and therapeutic targets. WNT6 was recently identified as a new oncogenic molecule in glioblastoma (GBM), with prognostic value in patients, but the mechanisms underlying WNT6 aberrant expression in glioma are still unknown. WNT6 was overexpressed in a subset of gliomas independently of IDH mutations, 1p/19q codeletion status, and WNT6 gene copy number. Interestingly, WNT6 expression is associated with the DNA methylation levels of particular CpG regions at both the WNT6 promoter and the gene body in glioma patient samples. HOXA9, a transcription factor previously associated with poorer clinical outcome in GBM, was identified as a novel transcriptional regulator of WNT6, activating the WNT/β-catenin pathway in vitro and in vivo. In various cohorts of glioma patients, mRNA levels of WNT6 and HOXA9 were significantly correlated, extending our in vitro and in vivo findings into the clinical setting. Interestingly, this novel molecular link between WNT6 and HOXA9 was not limited to glioma, as they were co-expressed also in patients with other tumor types. Clinically, WNT6 was a prognostic biomarker of shorter survival in GBM, independently of HOXA9 expression. Concomitant high expression of both WNT6 and HOXA9 identified a subgroup of patients with particularly dismal survival. These findings describe novel WNT6 regulatory mechanisms in GBM, establishing particular DNA methylation patterns and HOXA9 as critical regulators of WNT6 expression in glioma. This HOXA9-WNT6 molecular link supports WNT signaling in GBM cells and is a powerful prognostic biomarker, highlighting the clinical relevance of this axis in patients. Novel therapies targeting WNT6-HOXA9 signaling may thus be useful for this deadly disease.info:eu-repo/semantics/publishedVersio

An insight into the synthesis of cationic porphyrin-imidazole derivatives and their photodynamic inactivation efficiency against Escherichia coli

New porphyrin-imidazole derivatives were synthesised by Radziszewski reaction between 2-formyl-5,10,15,20-tetraphenylporphyrin 1 and several (hetem)aromatic 1,2-diones, which after cationization afforded promising monocationic photosensitizers 3a-d. Singlet oxygen studies have demonstrated that all the cationic porphyrin-imidazole conjugates 3a-d were capable to produce cytotoxic species. These photosensitizers were able to photoinactivate Eschericha coli and their inactivation profile was improved in the presence of KI.The authors are grateful to University of Aveiro and FCT/MCT for the financial support for QOPNA research Unit (FCT UID/QUI/00062/2019), the LAQV-REQUIMTE (UIDB/50006/2020), CESAM (UID/AMB/50017/2019) and CQUM (QUI/UI0686/2018) through national founds and, where applicable, co-financed by the FEDER, within the PT2020 Partnership Agreement, and to the Portuguese NMR Network. The research contract of N.M.M. Moura (REF.-048-88-ARH/2018) is funded by national funds (OE), through FCT - Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19

The European Seismic Risk Model 2020 (ESRM20)

This study describes the development of the various components of the European Seismic Risk Model 2020 (ESRM2020) which will be able to generate, using open-source software developed by the GEM Foundation (the Open Quake-engine), a number of Europe-wide risk metrics including average annualised human and economic losses (AAL), probable maximum losses (PML), and risk maps showing the losses for specific return periods or scenario events. The latest developments towards pan-European exposure models for residential and non-residential buildings and fragility/vulnerability models for damage, economic loss and casualty assessment will be presented. For engineered buildings within the exposure model (reinforced concrete, steel), a simulated design is undertaken using the key aspects of seismic design codes in force across Europe over the past 100 years. The designed MDOF building is then transformed to a SDOF model and nonlinear dynamic analyses are run using a large number of ground motion records, after which cloud analysis is used to develop the fragility functions. For non-engineered buildings (unreinforced masonry, confined masonry, adobe), the SDOF models have been directly developed from simplified formulae, experimental tests and previous studies. Collaboration from local experts at various stages of the model development, initiated through workshops, is an important component of the model, as well as the extensive calibration and validation

A rocky planet transiting a nearby low-mass star

M-dwarf stars -- hydrogen-burning stars that are smaller than 60 per cent of the size of the Sun -- are the most common class of star in our Galaxy and outnumber Sun-like stars by a ratio of 12:1. Recent results have shown that M dwarfs host Earth-sized planets in great numbers: the average number of M-dwarf planets that are between 0.5 to 1.5 times the size of Earth is at least 1.4 per star. The nearest such planets known to transit their star are 39 parsecs away, too distant for detailed follow-up observations to measure the planetary masses or to study their atmospheres. Here we report observations of GJ 1132b, a planet with a size of 1.2 Earth radii that is transiting a small star 12 parsecs away. Our Doppler mass measurement of GJ 1132b yields a density consistent with an Earth-like bulk composition, similar to the compositions of the six known exoplanets with masses less than six times that of the Earth and precisely measured densities. Receiving 19 times more stellar radiation than the Earth, the planet is too hot to be habitable but is cool enough to support a substantial atmosphere, one that has probably been considerably depleted of hydrogen. Because the host star is nearby and only 21 per cent the radius of the Sun, existing and upcoming telescopes will be able to observe the composition and dynamics of the planetary atmosphere.Comment: Published in Nature on 12 November 2015, available at http://dx.doi.org/10.1038/nature15762. This is the authors' version of the manuscrip

HOXA9 promotes glioblastoma initiation, aggressiveness and resistance to therapy

Glioblastoma is the most common and malignant subtype of glioma, exhibiting remarkable resistance to treatment. Here we investigated the oncogenic potential of HOXA9 in gliomagenesis, the molecular and cellular mechanisms by which HOXA9 may render glioblastoma more aggressive, and how HOXA9 affects response to chemotherapy and prognosis. Expression microarrays were used to identify HOXA9 target genes. Stable glioblastoma cell lines with ectopic HOXA9 overexpression or shRNA-­mediated knockdown of HOXA9 were established to evaluate the roles of HOXA9 in cell viability, death, invasion, and response to temozolomide. Subcutaneous and orthotopic intracranial xenograft models of glioblastoma were established to evaluate the oncogenic potential of HOXA9 in vivo, and its role in response to temozolomide and overall survival. Transcriptomic analyses identified novel HOXA9-­target genes that have key roles in critical cancer processes, including cell proliferation, adhesion, DNA metabolism and repair, and stem cell maintenance. Functional assays with a variety of glioblastoma cells revealed that HOXA9 promotes cell viability, stemness, and invasion; conversely, HOXA9 displayed anti-­apoptotic functions. Additionally, ectopic expression of HOXA9 promoted the malignant transformation of human immortalized astrocytes in an intracranial orthotopic mouse model of glioblastoma, and caused tumor-­associated death. HOXA9 also mediated resistance to temozolomide treatment both in vitro and in vivo. Mechanistically, BCL2 was identified as a novel HOXA9 target that may be therapeutically targeted. Indeed, the pharmacological inhibition of BCL2 with ABT-­737 specifically reverted temozolomide resistance in HOXA9-­positive cells. These data establish HOXA9 as a critical driver of glioma initiation, aggressiveness and resistance to therapy