Yes / Thermal degradation of polyamide 6 (PA6)/organoclay nanocomposites is a serious impediment to wider applications of these nanocomposites. In this study, a solution is proposed based on the well‐established use of chain extenders. As in PA6, thermal degradation, in the absence of moisture, produces broken polymer chains with amide end groups, a chain extender with anhydride functionalities, known to be strongly reactive with amide groups, was used to reconnect the chains. Experiments conducted using a laboratory twin‐screw extruder were first checked, through transmission electron microscopy observations, to have produced good organoclay intercalation and exfoliation into PA6. Following from this, samples with the chain extender added were produced and characterized. The data obtained were conclusive in the effectiveness of the chain extender: for the chain extended nanocomposites, there is an enhancement in the value of the complex viscosity by 7 times and in the storage modulus by 88 times, while the tensile modulus increased by 57% compared with the neat PA6. The nonchain extended nanocomposite achieved in comparison an enhancement of 2 times the value of the complex viscosity and 19 times the storage modulus while the tensile modulus increased by 53% compared to the neat PA6. These data provide conclusive proof on the rationale that anhydride functionalities should be sought when developing chain extenders for PA6 nanocomposites. / Government of Turkey

Yes / The realisation that unregulated activation of the Janus kinase–signal transducer and activator of transcription (JAK–STAT) pathway is a key driver of a wide range of diseases has identified its components as targets for therapeutic intervention by small molecule inhibitors and biologicals. In this review, we discuss JAK-STAT signalling pathway inhibition by the inducible inhibitor “suppressor of cytokine signaling 3 (SOCS3), its role in diseases such as myeloproliferative disorders, and its function as part of a multi-subunit E3 ubiquitin ligase complex. In addition, we highlight potential applications of these insights into SOCS3-based therapeutic strategies for management of conditions such as vascular re-stenosis associated with acute vascular injury, where there is strong evidence that multiple processes involved in disease progression could be attenuated by localized potentiation of SOCS3 expression levels. / British Heart Foundation; Chief Scientist's Office; NHS Greater Glasgow and Clyde Research Endowment Fund; BBSRC

Yes / The level of glutamine (Gln) deamidation in bone collagen provides information on the diagenetic history of bone but, in order to accurately assess the extent of Gln deamidation, it is important to minimise the conditions that may induce deamidation during the sample preparation. Here we report the results of a preliminary investigation of the variability in glutamine deamidation levels in an archaeological bone due to: a) sampling location within a bone; b) localised diagenesis; and c) sample preparation methods. We then investigate the effects of pre-treatment on three bone samples: one modern, one Medieval and one Pleistocene. The treatment of bone with acidic solutions was found to both induce deamidation and break down the collagen fibril structure. This is particularly evident in the Pleistocene material (~80,000 years BP) considered in this study. We show that ethylenediaminetetraacetic acid (EDTA), when used as an alternative to hydrochloric acid (HCl) demineralisation, induces minimal levels of deamidation and maintains the collagen fibril structure. Areas of bone exhibiting localised degradation are shown to be correlated with an increase in the levels of Gln deamidation. This indicates that the extent of Gln deamidation could provide a marker for diagenesis but that sampling is important, and that, whenever possible, subsamples should be taken from areas of the bone that are visually representative of the bone as a whole. Although validation of our observations will require analysis of a larger sample set, deamidation measurements could be a valuable screening tool to evaluate the suitability of bone for further destructive collagen analyses such as isotopic or DNA analysis, as well as assessing the overall preservation of bone material at a site. The measure of bone preservation may be useful to help conservators identify bones that may require special long-term storage conditions. / NERC (NE/J500197/1), Yorkshire Forward - Northern Way Initiative, Science City York, Gordon and Betty Moore Foundation, Leverhulme Trust

No / We have investigated the susceptibility of degraded human hair shaft samples to contamination by exogenous sources of DNA, including blood, saliva, skin cells, and purified DNA. The results indicate that on the whole hair shafts are either largely resistant to penetration by contaminant DNA, or extremely easy to successfully decontaminate. This pertains to samples that are both morphologically and biochemically degraded. We suggest that this resistance to the incorporation of contaminant DNA relates to the hydrophobic and impermeable nature of the keratin structures forming the hair shaft. Therefore, hair samples represent an important and underestimated source of DNA in both forensic and ancient DNA studies.

No / Hydrolytic degradation studies have been undertaken on Maxon B, a bioresorbable block copolymer of polyglycolic acid (PGA) and polytrimethylene carbonate (TMC). Isotropic and oriented samples were studied by dynamic mechanical measurements over a wide range of temperatures. In addition to mechanical tests, water content and mass loss were also determined on the degraded samples. At early stages of degradation water content was the dominant factor and plasticisation lead to reductions in the glass transition temperatures of the PGA and TMC components. Orientation was shown to give significant improvements in the mechanical properties, including overall increases in modulus and an increase in the glass transition temperature of the PGA component, which is important for the behaviour at body temperature (37 °C). Oriented samples also showed significantly less reduction in mechanical properties on degradation. Simple one-dimensional Takayanagi models were used to provide useful insight into the understanding of the mechanical behaviour.

La protéine PCNA est un facteur d'échafaudage polyvalent pour plus de cinquante protéines impliquées dans le métabolisme d'ADN, notamment dans la réplication et la réparation. Comment les échanges entre les partenaires de PCNA sont régulés est actuellement mal compris. Parmi ses partenaires, CDT1, p21 et PR-Set7/Set8 possèdent un motif d'interaction avec PCNA particulier, nommé « PIP degron », qui favorise leur protéolyse d'une manière dépendante de l'E3 ubiquitine ligase CRL4Cdt2. Après irradiation aux UV-C, le facteur d'initiation de la réplication CDT1 est rapidement détruit d'une manière dépendante de son PIP degron, mais le rôle de cette dégradation est inconnu. Dans cette étude, j'ai analysé la fonction du PIP degron de CDT1 et fourni des évidences expérimentales qui montrent que l'inhibition de la dégradation de Cdt1 par CRL4Cdt2 dans les cellules de mammifères compromet la relocalisation de l'ADN polymérase translesionnelle eta en foyers nucléaires induits par les irradiations UV-C. En élargissant cette étude à d'autres partenaires de PCNA, nous avons constaté que seuls les protéines qui contiennent un PIP degron, et pas un PIP box canonique comme celui de FEN1 et p15 (PAF), interfèrent avec la formation de foyers de pol eta. La mutagenèse du PIP degron de CDT1 a révélé qu'un résidu de thréonine conservé parmi les PIP degrons est essentiel pour l'inhibition de la formation des foyers de pol eta. Les résultats obtenus suggèrent que l'élimination de protéines contenant des PIP degrons par la voie CRL4Cdt2 régule le recrutement de pol eta au niveau des sites de dommages induits par les UV-C. / The sliding clamp PCNA is a versatile scaffold for more than fifty proteins involved in DNA metabolism such as replication and repair. How the switch between PCNA partners is regulated is currently not fully understood. Among its partners, Cdt1, p21 and PR-Set7/Set8 contain a specialized PCNA-binding motif named « PIP degron » that promotes their proteolysis in a fashion dependent on the E3 ubiquitin ligase CRL4Cdt2. Upon UV-irradiation, the replication initiation factor Cdt1 is rapidly destroyed in a PIP degron-dependent manner but the role of this degradation is unknown. Here we have analyzed the function of Cdt1 PIP degron and we provide evidence that interference with CRL4Cdt2-mediated destruction of Cdt1 in mammalian cells compromises PCNA-dependent relocalisation of the DNA translesion polymerase eta into UV-induced nuclear foci. By extending this analysis to other PCNA partners, we found that only PIP degrons, as compared to canonical PCNA-binding motifs of Fen1 and p15(PAF), interfere with pol eta focus formation. Mutagenesis of Cdt1 PIP degron revealed that a threonine residue conserved in PIP degrons is critical for inhibition of pol eta focus formation. Our results suggest that removal of high-affinity PIP degron-containing proteins from PCNA by CRL4Cdt2 pathway regulates pol eta recruitment to sites of UV-damage.

Os poliésteres alifáticos, como poli(caprolactona) (PCL) e poli(ácido lático) (PLA), são comumente usados em produtos biodegradáveis. Esses materiais são ecológicos e o uso de fibras vegetais com estes polímeros corrobora em uma alternativa de lidar com os resíduos da agroindústria e da indústria madeireira. O objetivo deste estudo foi de investigar as propriedades resultantes da degradação abiótica e biótica das bioblendas de PCL/PLA e seus biocompósitos com fibras vegetais. As fibras vegetais avaliadas foram a de babassu (Orbignya phalerata), de cana-de-açúcar (Saccharum spp) e farinha de madeira (Pinus Ellioti). A bioblenda de PCL/PLA foi utilizada como referência na proporção de 70/30, 50/50 e 30/70 (m/m) e para cada biocompósito foi utilizado 20% de fibra vegetal com duas granulometrias, de 35 e 45 mesh. As misturas foram processadas via extrusão e moldados por compressão térmica em formato de fitas. As amostras foram expostas a intemperismo natural por um período total de 120 dias e avaliadas as mudanças de suas propriedades mecânicas, físicas, químicas, morfológicas e térmicas a cada 30 dias. Evoluções das superfícies deterioradas das amostras foram observadas por MEV e demonstraram que foram ocasionadas pelas condições climáticas severas e confirmadas por FTIR através de uma diminuição considerável dos grupos ésteres. A incorporação de maior quantidade PLA ao PCL nas bioblendas aumentou o módulo de elasticidade e resistência à tração. Os biocompósitos reforçados com fibras vegetais com granulometria de 45 mesh destacaram-se em maior resistência à tração, e, após envelhecimento natural de 30 dias apresentaram menor decaimento assim como o módulo elástico. A estabilidade térmica dos biocompósitos com farinha de madeira de Pinus e fibras de cana-de-açúcar foi maior do que as de babaçu. O biocompósito reforçado com fibras de cana-de-açúcar destacou-se com maior desempenho mecânico indicando que houve uma melhor interação entre fibra e matriz polimérica. Resultados do monitoramento da degradação biótica avaliados em câmara respirométrica indicaram que o PCL apresentou menor velocidade de biodegradação em relação ao PLA. As bioblendas e biocompósitos com maior teor de PCL mostraram menor produção de CO2 ao longo do período avaliado. O biocompósito com menor teor de PCL e reforçado com fibra de cana-de-açúcar destacou-se com uma maior velocidade de biodegradação e pela maior produção de CO2. As propriedades resultantes da degradação abiótica e biótica destes materiais auxiliam no desenvolvimento de produtos de vida útil curta, bem como, na preservação do meio ambiente. / Aliphatic polyesters, such as poly(caprolactone) (PCL) and poly(lactic acid) (PLA) have been commonly used in biodegradable products. These materials are ecological and use of vegetal fibers in these composites also provides an alternative way to deal with agricultural residues. This study aims to evaluate the properties resulting from the abiotic and biotic degradation of PCL/PLA bioblends and their biocomposites. The vegetal fibers evaluated were babassu (Orbignya phalerata), sugarcane (Saccharum spp) and wood flour (Pinus Ellioti). PCL/PLA bioblends were used as reference with 70/30, 50/50 and 30/70 (w/w) ratio and each biocomposite had 20% of vegetal fiber content with 35 and 45 mesh granulometry was used. The bioblends were processed by extrusion and molded in tape format. The samples were exposed to natural weathering for 120 days and the changes in their mechanical, physical, chemical, morphological and thermal properties were evaluated every 30 days. Damaged surface evolution was performed by SEM and showed that they were caused by the severe climatic conditions and confirmed by FTIR through a considerable decrease of the ester groups. Addition of PLA to the PCL in the bioblends increased the modulus of elasticity and tensile strength. Reinforcements with vegetable fibers with 45 mesh granulometry increased tensile strength, and, after natural aging of 30 days, showed lower decrease as well as the modulus. Thermal stability of the biocomposites with wood flour and sugarcane fibers was higher than babassu. Biocomposites reinforced with sugarcane fibers highlighted in the higher mechanical performance indicating that there was a better interaction between fiber and polymer matrix. Results of the monitoring of biotic degradation indicated that PCL presented a lower rate of biodegradation in relation to PLA. Bioblends and biocomposites with higher PCL content showed lower CO2 generation over the period evaluated. Biocomposites with lower content of PCL and reinforced with sugarcane fiber stood out in the greater speed of biodegradation and the greater production of CO2. Properties resulting from the abiotic and biotic degradation prompted changes in its structures and to facilitate its degradation in times lower than conventional and aid in the development of short-lived products as well as in the preservation of the environment.

The replacement of artificial with natural dyes is one of the most challenging research fields in the food production area. Recent studies have shown that some frequently used synthetic colours, called the “Southampton 6 Colours” may be linked with hyperactivity in children. The purpose of this work is to analyse the degradation behaviour of black carrot, a natural, red dye commonly used for colouring food products, and subsequently improve its stability during heat and storage conditions. The stability of the black carrot mixture to heat exposure was investigated at a range of pH values by heat-treating aqueous solutions in a domestic oven at around 180oC to maintain the temperature at 100oC and the powdered material in a furnace at 180oC (typical baking conditions). 1H NMR (800 MHz) spectroscopy was used for the assignment of the aromatic chemical shifts of the black carrot mixture by overlaying them with the characterised 1H NMR chemical shifts of the individual components separated by RP-HPLC. Integration of high-resolution 1H NMR (800 MHz) spectra was used to follow the relative degradation of each of the components. Different procedures for the complexation of black carrot with metal oxides were developed, for which colourants of different colour shades were prepared. Spectroscopic techniques were used to follow the degradation of the complexes which were heat-treated at 180oC. Nano-scale investigation of the metal oxide powders was also carried out. The optimised colourants were tested on a bench scale and subsequently on an industrial scale in food pilot procedures. The successful complexes produced were found to be more heat stable compared to the commercial black carrot dye. The developed technologies are cheap and easy-to-produce methods to create intense heat and storage stable coloured pigments which can be used for the replacement of existing artificial dyes during food processing.

Many studies measuring the occurrence of pharmaceuticals, understanding their environmental fate and the risk they pose to surface water resources have been published. However, very little is known about the relevant transformation products which result from the wide range of biotic and abiotic degradation processes that these compounds undergo in sewers, storage tanks, during engineered treatment and in the environment. Thus, the present study primarily investigated the degradation of the steroid progesterone (P4) in natural systems (rivers), with a focus on the identification and characterisation of transformation products. Initial work focussed on assessing the removal of selected compounds (Diclofenac, Fluoxetine, Propranolol and P4) from reed beds, with identification of transformation products in a field site being attempted. However, it was determined that concentrations of parent compounds and products would be too low to work with in the field, and a laboratory study was designed which focussed on P4. Focus on P4 was based on literature evidence of its rapid biodegradability relative to the other model compounds and its usage patterns globally. River water sampling for the laboratory-based degradation study was carried out at 1 km downstream of four south east England sewage works (Blackbirds, Chesham, High Wycombe and Maple Lodge) effluent discharge points. Suspected P4 transformation products were initially identified from predictions by the EAWAG Biocatalysis Biodegradation Database (EAWAG BBD) and from a literature review. At a later stage of the present work, a replacement model for EAWAG BBD (enviPath) which became available, was used to predict P4 degradation and results were compared. Samples were analysed using low resolution and accurate-mass time-of-flight mass spectrometers. Three degradation studies were conducted. Sampling for all studies was carried out at the same time in the year to minimize temporal variability in conditions and allow for effective comparison of results. Androgenic and progesterone yeast screens were carried out to assess the biological activity of transformation products.

Submitted by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-09-21T18:28:49Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) FABIO DE SOUZA BARBOSA.pdf: 1689958 bytes, checksum: 1fe429224460761440aa3dfeb3cbe066 (MD5) / Approved for entry into archive by Marcos Anselmo (marcos.anselmo@unipampa.edu.br) on 2016-09-21T18:29:20Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) FABIO DE SOUZA BARBOSA.pdf: 1689958 bytes, checksum: 1fe429224460761440aa3dfeb3cbe066 (MD5) / Made available in DSpace on 2016-09-21T18:29:20Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) FABIO DE SOUZA BARBOSA.pdf: 1689958 bytes, checksum: 1fe429224460761440aa3dfeb3cbe066 (MD5) Previous issue date: 2015-07-17 / O doripenem é um antibiótico β-lactâmico de amplo espectro de ação. Pertencente ao grupo das carbapenemas, caracteriza-se por apresentar elevada potência e atividade frente à cepas Gram-negativas, produtoras de β-lactamases de espectro estendido (ESBL) e β-lactamases ampC. Apesar de sua grande importância clínica, os antibióticos carbapenêmicos não apresentam boa estabilidade quando em solução, o que é demonstrado em diversos trabalhos descritos na literatura científica. Para o doripenem, há vários trabalhos descritos na literatura que ressaltam sua importância clínica e sua atividade antibiótica. Porém, nota-se a escassez de trabalhos que enfoquem sua estabilidade físico-química, seus produtos e suas rotas de decomposição. O presente trabalho tem como objetivo a validação de um método analítico indicativo de estabilidade por ultra fast liquid chromatography (UFLC), e a avaliação da estabilidade do doripenem em solução, quando submetido a estresse térmico, oxidativo, fotólise e hidrólise em meio ácido e meio alcalino, e determinação da cinética química de decompsição. Para proposição da estrutura química dos produtos de degradação, foram realizadas análises por cromatografia líquida com detecção por espectrometria de massas (LC-MS). O método cromatográfico descrito neste trabalho demonstrou-se adequado para determinação do doripenem na forma de pó para solução injetável, possuindo performance indicativa de estabilidade. A faixa linear do método foi de 5,0 a 40,0 μg/mL, sem desvios de linearidade, sendo estatisticamente comprovada por meio de ANOVA. Com o auxilio do desenho experimental de Plackett–Burman, o método demonstrou-se robusto frente a uma série de fatores. O estudo de degradação forçada demostrou a susceptibilidade do doripenem a diversos fatores de degradação, com acentuada instabilidade frente à hidrólise ácida e alcalina, observando-se degradação aproximada de 60% do seu teor em apenas 2 minutos sob condições alcalinas. A decomposição oxidativa do fármaco seguiu uma cinética de segunda ordem, com constante de velocidade de reação de 0,000086 e 0,00010%-1.min-1, quando submetido à degradação em H2O2 a 3 e 10%, respectivamente. A decomposição térmica apresentou uma energia de ativação de aproximadamente 15 Kcal/mol, valor característico de reações de hidrólise. E na análise cromatográfica com detecção por espectrometria de massas, observou-se que os principais produtos de degradação formados sob condições de termólise e oxidação, apresentam massas moleculares semelhantes, sendo possível a proposição da estrutura química dos mesmos. / Doripenem is a β-lactam antibiotic with a broad spectrum of antimicrobial activity, including gram-negative strains, and producers of extended spectrum β-lactamases (ESBL) and ampC β-lactamases ampC. Despite its great clinical importance, carbapenems do not show good stability when incorporated as solution, as reported in several studies. In reference to doripenem, several works have describing its clinical use, efficacy data and cases of resistance. However, few works mention the drug stability, in terms of degradation products and routes of decomposition. The present work aimed to develop and validate a stability-indicating method by ultra-fast liquid chomatograph (UFLC) for doripenem in powder for injection, purposing an evaluation of stability of reconstituted solution using stress conditions of heat, oxidation, acid hydrolysis, alkaline hydrolysis and photolysis. The chemical kinetic of decomposition was also assayed for thermal and oxidative degradation. For identification of degradation products, the degraded samples where submitted to analysis by LC-MS. The chromatographic method described here proved to be stability-indicating and suitable for the determination of doripenem in drug formulation. The method linearity was performed in the range of 5 to 40 g mL-1, whose correlation coefficient (r) was 0.9999. The robustness testing, assayed against a variety of factors, allowed verifying that the method accept small variations in routine analysis. The forced degradation demonstrated the susceptibility of doripenem to several decomposition factors, being intense the instability to acidic and alkaline hydrolysis. In basic media, the drug residual content was approximately 40% in 2 minutes. At oxidative decomposition, the drug follows second-order kinetics, with a rate reaction of 0.000086 and 0.00010 %-1 min-1, respectively for H2O2 at 3.0 and 10.0 %. The thermal decomposition showed an activation energy of 15 kcal mol-1, a characteristic value for hydrolysis reactions. The analysis by LC-MS revealed that the major degradation products formed under oxidizing conditions and thermolysis present molecular weight (411, 427, 437, 634, 650 and 664). The stability of doripenem must be carefully observed, mainly after reconstitution and storage in adverse conditions of temperature.