Kraft lignin solubility and its chemical modification in deep eutectic solvents

Lignin stands as a promising raw material to produce commodities and specialty chemicals, yet its poor solubility remains a big challenge. Recently, deep eutectic solvents (DES) have been proposed as sustainable solvents with high potential to dissolve and valorize lignin. In the present study, the ability of DES based on cholinium chloride ([Ch]Cl) combined with alcohols and carboxylic acids as hydrogen bond donors (HBDs) to dissolve kraft lignin and to change its chemical structure was examined. The influence of the chemical nature of HBDs, water content, and HBD:hydrogen bond acceptor (HBA) molar ratio on the solubility of kraft lignin in DES was studied (313.15 K). The kraft lignin solubility was enhanced by increasing both the HBD’s carbon chain length and the molar ratio, with [Ch]Cl:HEXA (1,6-hexanediol) and [Ch]Cl:MaleA (maleic acid) being the best studied solvents for kraft lignin dissolution, while the addition of water was a negative factor. The thermal treatments (393.15 K) of kraft lignin show that carboxylic acid-based DES promote chemical modifications to kraft lignin, including the disruption of several C–O covalent type bonds (e.g., β-O-4, α-O-4 and α-O-α), while alcohol-based DES were found to be nonderivatizing solvents maintaining the lignin chemical structure. These results show the versatility of DES, which, depending on their chemical nature, may offer distinct strategies for lignin valorization.publishe

A canine leishmaniasis pilot survey in an emerging focus of visceral leishmaniasis: Posadas (Misiones, Argentina)

<p>Abstract</p> <p>Background</p> <p>An increasing number of reports are calling our attention to the worldwide spread of leishmaniasis. The urbanization of zoonotic visceral leishmaniasis (VL) has been observed in different South American countries, due to changes in demographic and ecological factors. In May 2006, VL was detected for the first time in the city of Posadas (Misiones, Argentina). This event encouraged us to conduct a clinical and parasitological pilot survey on domestic dogs from Posadas to identify their potential role as reservoirs for the disease.</p> <p>Methods</p> <p>One hundred and ten dogs from the city of Posadas were included in the study. They were selected based on convenience and availability. All dogs underwent clinical examination. Symptomatology related to canine leishmaniasis was recorded, and peripheral blood and lymph node aspirates were collected. Anti-<it>Leishmania </it>antibodies were detected using rK39-immunocromatographic tests and IFAT. Parasite detection was based on peripheral blood and lymph node aspirate PCR targeting the <it>SSUrRNA </it>gene. Molecular typing was addressed by DNA sequence analysis of the PCR products obtained by <it>SSUrRNA </it>and ITS-1 PCR.</p> <p>Results</p> <p>According to clinical examination, 69.1% (76/110) of the dogs presented symptoms compatible with canine leishmaniasis. Serological analyses were positive for 43.6% (48/110) of the dogs and parasite DNA was detected in 47.3% (52/110). A total of 63 dogs (57.3%) were positive by serology and/or PCR. Molecular typing identified <it>Leishmania infantum </it>(syn. <it>Leishmania chagasi</it>) as the causative agent.</p> <p>Conclusions</p> <p>This work confirms recent findings which revealed the presence of <it>Lutzomyia longipalpis</it>, the vector of <it>L. infantum </it>in this area of South America. This new VL focus could be well established, and further work is needed to ascertain its magnitude and to prevent further human VL cases.</p

Lugar Comum: habitar (n)a cidade do Porto. Princípios de intervenção para uma área de habitação municipal

'Lugar Comum: habitar (n)a cidade do Porto' consiste num exercício de observação, interpretação pelo desenho e reflexão crítica sobre o potencial de uma intervenção de densificação habitacional numa área de habitação municipal em contexto portuense. A propósito do 'Concurso para criação de habitação destinada ao mercado de arrendamento a custo acessível e reabilitação de áreas habitacionais municipais em Lordelo do Ouro' desenvolve- se a hipótese de tirar proveito das intervenções enquanto estratégia articuladora de continuidades e complementaridades urbanas e sociais. Neste sentido, pretende-se criar um entendimento sobre a possibilidade de intervir de forma efectivamente integrada e integradora, sem potenciar discrepâncias urbanas, reequilibrando-as a partir das qualidades intrínsecas ao lugar que integra os Bairros Dr. Nuno Pinheiro Torres e de Lordelo. A estratégia que se propõe experimenta o princípio da densificação minuciosa de um conjunto de lugares que integram o grande conjunto habitacional, procurando clarificar e complementar as funções (para além) de habitar. Este é o território Lugar Comum em que se pretende intervir: um lugar estabelecido entre o ambiente construído e não-construído e o millieu que aqui se encerra.'Lugar Comum: habitar (n)a cidade do Porto' is an exercise of observation and interpretation through mapping and critical analysis, focusing on the qualities of densification as a modus operandi in an area which is already inhabited and part of a major public housing settlement. The design competition for affordable housing and urban regeneration of a designated public area in Lordelo do Ouro creates the opportunity to further develop the strategy for intervention as one which articulates social and urban continuity and co-existence. The aim is to develop an understanding of the possibilities to intervene in order to integrate and become integrated without enhancing urban discrepancies. The idea is to work towards the re-balancing of urban functions by taking advantage of the inextricable qualities of the place. The proposed strategy follows a careful densification of a selection of places within the wider housing settlement, aiming at clarifying and completing the functions associated with dwelling. This is the new territory, the Common Place in which we are to intervene: one that is established in the articulation between public space, built environment and social milieu

Assessing the Influence of Dyes Physico-Chemical Properties on Incorporation and Release Kinetics in Silk Fibroin Matrices

Silk fibroin (SF) is a promising and versatile biodegradable protein for biomedical applications. This study aimed to develop a prolonged release device by incorporating SF microparticles containing dyes into SF hydrogels. The influence of dyes on incorporation and release kinetics in SF based devices were evaluated regarding their hydrophilicity, molar mass, and cationic/anionic character. Hydrophobic and cationic dyes presented high encapsulation efficiency, probably related to electrostatic and hydrophobic interactions with SF. The addition of SF microparticles in SF hydrogels was an effective method to prolong the release, increasing the release time by 10-fold