Magnetic properties of GdT2T_2Zn20_{20} (T = Fe, Co) investigated by X-ray diffraction and spectroscopy

We investigate the magnetic and electronic properties of the Gd$T_2$Zn$_{20}$ ($T$ = Fe and Co) compounds using X-ray resonant magnetic scattering (XRMS), X-ray absorption near-edge structure (XANES) and X-ray magnetic circular dichroism (XMCD) techniques. The XRMS measurements reveal that the GdCo$_2$Zn$_{20}$ compound has a commensurate antiferromagnetic spin structure with a magnetic propagation vector $\vec{\tau}$ = $(\frac{1}{2},\frac{1}{2},\frac{1}{2})$ below the N\'eel temperature ($T_N \sim$ 5.7 K). Only the Gd ions carry a magnetic moment forming an antiferromagnetic structure with magnetic representation $\Gamma_6$. For the ferromagnetic GdFe$_2$Zn$_{20}$ compound, an extensive investigation was performed at low temperature and under magnetic field using XANES and XMCD techniques. A strong XMCD signal of about 12.5 $\%$ and 9.7 $\%$ is observed below the Curie temperature ($T_C \sim$ 85 K) at the Gd-$L_2$ and $L_3$ edges, respectively. In addition, a small magnetic signal of about 0.06 $\%$ of the jump is recorded at the Zn $K$-edge suggesting that the Zn 4$p$ states are spin polarized by the Gd 5$d$ extended orbitals

The indefinite-interrogative affinity in sign languages: the case of Catalan Sign Language

Prior studies on spoken languages have shown that indefinite and interrogative pronouns may be formally very similar. Our research aims to understand if sign languages exhibit this type of affinity. This paper presents an overview of the phenomenon and reports on the results of two studies: a cross-linguistic survey based on a sample of 30 sign languages and an empirical investigation conducted with three deaf consultants of Catalan Sign Language (LSC). Our research shows that, in sign languages, certain signs have both existential and interrogative readings and it identifies the environments that make existential interpretations available in LSC

From antimicrobial to anticancer peptides : a review

Antimicrobial peptides (AMPs) are part of the innate immune defense mechanism of many organisms. Although AMPs have been essentially studied and developed as potential alternatives for fighting infectious diseases, their use as anticancer peptides (ACPs) in cancer therapy either alone or in combination with other conventional drugs has been regarded as a therapeutic strategy to explore. As human cancer remains a cause of high morbidity and mortality worldwide, an urgent need of new, selective, and more efficient drugs is evident. Even though ACPs are expected to be selective toward tumor cells without impairing the normal body physiological functions, the development of a selective ACP has been a challenge. It is not yet possible to predict antitumor activity based on ACPs structures. ACPs are unique molecules when compared to the actual chemotherapeutic arsenal available for cancer treatment and display a variety of modes of action which in some types of cancer seem to co-exist. Regardless the debate surrounding the definition of structure-activity relationships for ACPs, great effort has been invested in ACP design and the challenge of improving effective killing of tumor cells remains. As detailed studies on ACPs mechanisms of action are crucial for optimizing drug development, in this review we provide an overview of the literature concerning peptides' structure, modes of action, selectivity, and efficacy and also summarize some of the many ACPs studied and/or developed for targeting different solid and hematologic malignancies with special emphasis on the first group. Strategies described for drug development and for increasing peptide selectivity toward specific cells while reducing toxicity are also discussed.The authors thank Fundação para a Ciência e a Tecnologia (FCT- MEC, Portugal) for funding—PTDC/QUI-BIO/112929/2009. Diana Gaspar also acknowledges FCT for fellowship SFRH/BPD/ 73500/2010 and A. Salome Veiga for funding within the FCT Investigator Programme (IF/00803/2012

Lime-metakaolin mortars for historical buildings repair: study of the hardening reaction

International Conference Durable Structures: from construction to rehabilitation. Lisbon, LNEC, 31 May-1 June 2012Formulation of mortars with adequate durability and strength is nowadays one of the major challenges in historical buildings repair. Pozzolanic materials have been used during centuries in air lime mortars to improve their mechanic and durability characteristics. This paper is part of an extensive work being developed in Portugal, aiming to characterize lime-metakaolin mortars to be employed for historical buildings conservation and repair. This paper presents the results of hardening reaction study until 90 days of curing in humid conditions. The results show that in the adopted curing conditions, the hydration reaction occurs mostly for early ages of curing (28 days) while the carbonation reaction is mostly dominant for longer ages (90 days)

Nanoconsolidants for lime mortars of wall paintings as a good alternative of traditional consolidants

Carbonate stones and wall paintings, as an irremovable part of the architectural heritage, are subject to constant attack by soluble salts and pollutants. They can undergo different kinds of degradation, including corrosion by acid rain, physical erosion, cycles of salts crystallization/solubilization and biodegradation due to bacteria, fungi or lichens. Often, past treatments tend to cause additional substrate damages. For instances, synthetic polymeric materials applied for work of art restoration as consolidants, protectives, adhesives or cleaning agents, initially were seen as a good treatment alternative. However, upon ageing they are subject to degradation which results in cross-linking or chain scission which consequently alter their own initial properties and accelerate the decay of the artwork by changing its physicochemical properties. Nanoconsolidants exhibit distinct properties when compared to their bulk analogues, and for the last decade have been seen as a good alternative of compatible materials for long term preservation of Cultural Heritage.[1,2] A highly efficient consolidant for stone or mortar must meet a large list of requisites: must be effective for long-term, be compatible with the damaged substrate, to induce mechanical improvement and protection from weathering to the material, among others. The application of micro- and nanoparticles (NPs) based on alkali-earth metal hydroxides for cultural heritage conservation has become more relevant, mainly for consolidation of historic lime mortars, biocalcarenite stone and for cellulose materials deacidification purposes. Our research intends to propose successful preparative strategies of sub-micro and nanolimes, and to study their efficiency in the inhibition of the degradation process and in the consolidation of wall renders. In this communication an overview of the main synthesis strategies to prepare nanoconsolidants for restoration of Cultural Heritage is carried out. We also report our attempts to develop nanoconsolidants based on alkali-earth metal hydroxides for lime mortars of wall paintings. Furthermore, we discuss their effectiveness for the improvement of the mechanical properties of lime mortars. [1] Baglioni, P.; Carretti, E.; Chelazzi, D., Nature Nanotechnology 2015, 10, 287. [2] Girginova, P. I.; Galacho, C.; Veiga, R.; Santos Silva, A.; Candeias, A., ChemSusChem 2018, 11, 4168.Post-doctoral grant (P.G.) SFRH/BPD/97692/201

Severe intracranial haemorrhage in neonatal alloimmune thrombocytopenia

Neonatal alloimmune thrombocytopenia is a rare (1/1000-5000 births) life-threatening disorder, caused by fetomaternal incompatibility for a fetal human platelet alloantigen inherited from the father, with production of maternal alloantibodies against fetal platelets, leading to severe thrombocytopenia and potential bleeding. Intracranial haemorrhage is the most feared complication. This report presents the case of a term newborn infant, born from caesarean section after a normal pregnancy, presenting signs of skin bleeding with different ages. Obstetric history included a previous spontaneous abortion after amniocentesis. Severe thrombocytopenia (4×10(9)/l platelets) was found and brain ultrasound showed multiple intracranial haemorrhages. Human platelet antigen (HPA) phenotyping showed maternal negative HPA-1a and paternal positive HPA-1a platelets. Strongly positive anti-HPA-1a and weakly positive anti-human leukocyte antigen class I alloantibodies were found in the mother. Multiple platelet transfusions, intravenous immunoglobulin and corticosteroid were given but favourable response was accomplished only after a compatible platelet transfusion. Brain MRI showed multiple subacute and chronic haemorrhages

Pontine and Extrapontine Myelinolysis

Introdução: A mielinólise define-se como uma doença desmielinizante aguda, associada a um quadro clínico de tetraplegia flácida e a incapacidade na fala e na deglutição. A patogenia em geral está associada a perturbações electrolíticas, particularmente hiponatrémia profunda e sua rápida correcção. A confirmação imagiológica do diagnóstico pode ser feita recorrendo à Ressonância Magnética Nuclear. Objectivo: Os autores fazem a descrição do caso clínico, evidenciando a sua evolução e programa de reabilitação instituído, realçando os ganhos da funcionalidade. São descritas também as intercorrências clínicas relevantes no atraso do diagnóstico. Caso clínico: Apresenta-se uma doente com antecedentes psiquiátricos e polidipsia, internada na sequência de um quadro convulsivo resistente à medicação, tendo sido identificada hiponatrémia e feita a sua correcção. Após a correcção a doente desenvolveu um quadro de tetraplegia e hipotonia generalizada, tendo realizado uma Ressonância Magnética compatível com o diagnóstico de mielinólise centropôntica e extrapôntica