The Fifteenth Annual Conference YUCOMAT 2013: Programme and the Book of Abstracts

The First Conference on materials science and engineering, including physics, physical chemistry, condensed matter chemistry, and technology in general, was held in September 1995, in Herceg Novi. An initiative to establish Yugoslav Materials Research Society was born at the conference and, similar to other MR societies in the world, the programme was made and objectives determined. The Yugoslav Materials Research Society (Yu-MRS), a nongovernment and non-profit scientific association, was founded in 1997 to promote multidisciplinary goal-oriented research in materials science and engineering. The main task and objective of the Society has been to encourage creativity in materials research and engineering to reach a harmonic coordination between achievements in this field in our country and analogous activities in the world with an aim to include our country into global international projects. Until 2003, Conferences were held every second year and then they grew into Annual Conferences that were traditionally held in Herceg Novi in September of every year. In 2007 Yu-MRS formed two new MRS: MRS-Serbia (official successor of Yu-MRS) and MRS-Montenegro (in founding). In 2008, MRS – Serbia became a member of FEMS (Federation of European Materials Societies)

The Fifteenth Annual Conference YUCOMAT 2013: Programme and the Book of Abstracts

The First Conference on materials science and engineering, including physics, physical chemistry, condensed matter chemistry, and technology in general, was held in September 1995, in Herceg Novi. An initiative to establish Yugoslav Materials Research Society was born at the conference and, similar to other MR societies in the world, the programme was made and objectives determined. The Yugoslav Materials Research Society (Yu-MRS), a nongovernment and non-profit scientific association, was founded in 1997 to promote multidisciplinary goal-oriented research in materials science and engineering. The main task and objective of the Society has been to encourage creativity in materials research and engineering to reach a harmonic coordination between achievements in this field in our country and analogous activities in the world with an aim to include our country into global international projects.\ud \ud \ud \ud Until 2003, Conferences were held every second year and then they grew into Annual Conferences that were traditionally held in Herceg Novi in September of every year. In 2007 Yu-MRS formed two new MRS: MRS-Serbia (official successor of Yu-MRS) and MRS-Montenegro (in founding). In 2008, MRS – Serbia became a member of FEMS (Federation of European Materials Societies)

Scientific Advances in STEM: From Professor to Students

This book collects the publications of the special Topic Scientific advances in STEM: from Professor to students. The aim is to contribute to the advancement of the Science and Engineering fields and their impact on the industrial sector, which requires a multidisciplinary approach. University generates and transmits knowledge to serve society. Social demands continuously evolve, mainly because of cultural, scientific, and technological development. Researchers must contextualize the subjects they investigate to their application to the local industry and community organizations, frequently using a multidisciplinary point of view, to enhance the progress in a wide variety of fields (aeronautics, automotive, biomedical, electrical and renewable energy, communications, environmental, electronic components, etc.). Most investigations in the fields of science and engineering require the work of multidisciplinary teams, representing a stockpile of research projects in different stages (final year projects, master’s or doctoral studies). In this context, this Topic offers a framework for integrating interdisciplinary research, drawing together experimental and theoretical contributions in a wide variety of fields

Biologically Inspired Engineering for Protein Stabilisation

Every year millions of lives are saved by vaccination and millions more could be saved with more efficient vaccination coverage. Thermostability of vaccines is one of the major reasons why many children who need vaccines most do not get all the shots they need. Vaccines need to be kept below 8°C throughout manufacturing, delivering and shipping which requires a cold-chain. This involves carrying vaccines in a cool box for days even weeks to small villages or islands with no electricity or any other infrastructure. One of the grand challenges in global health is to produce vaccines that do not require refrigeration. Here, a biologically inspired vaccine stabilisation method is proposed. The method is based on the fact that proteins entrapped in the fossil avian eggshell crystals are well preserved up to thousands of years in Africa where high-temperature vaccine stability is needed. The persistence of the ancient intra-crystalline proteins suggests that protein incorporation into the inorganic host could retard protein degradation for long periods of time without refrigeration. In the present work, biomimetic protein incorporation in calcium carbonate was investigated to produce intra-crystalline heat-stable vaccines. Intra-crystalline protein persistence in the fossil record has been shown for ostrich eggshell proteins and the most durable proteins are known to belong to the C-type lectin-like protein family. It is thought that at least one C-type lectin-like protein is found in the eggshells of every species. The most well known C-type lectin-like protein is the OC-17 from chicken eggshell. OC-17 and other C-type lectins have the highest concentration in eggshells compared to other eggshell proteins which suggests that they could lead understanding of efficient protein incorporation in calcium carbonate crystals. Apart from ostrich and chicken, C-type lectins from other species have not been studied in detail. For this reason, eggshells from 14 species were studied in the present work. The aim of the investigation is to quantify the effect of the organic matter on the eggshells which could allow inferring protein incorporation efficiency of different species. The mechanical properties of the eggshells were studied with nanoindentation. This allows probing the differences in the elastic modulus and hardness of eggshells which are affected by the intra-crystalline protein content. It was found that the elastic modulus differs among species, which is lowest at around 10 GPa for Bali myna and highest at around 60 GPa for ostrich. Similarly, the hardness changes from around 1 GPa for Bali myna to around 3 GPa for rhea. The chemical analysis was conducted with IR spectroscopy. The deviations in the absorption peaks of eggshells compared to pure calcium carbonate allows probing the extent of the amorphous structure of the eggshells. In addition, the comparison of the full-width at half maximum values of vibration modes in each spectrum provides information of the crystal order of the eggshells. Comparison of mechanical and chemical analyses of different species offers insights on the protein content of different eggshells which could lead identification of the most efficient C-type lectins in terms of protein incorporation ability. Because of the importance of eggshell C-type lectins for the vaccine preservation method proposed in the present work, the OC-17 was studied here in detail. First, a purification method was developed to extract OC-17 from chicken eggshell. Liquid chromatography was used to extract OC-17, OC-23 and lysozyme. Then, lysozyme was removed from solution using a lysozyme binding protein. In addition, OC-17 was cloned to synthesize a recombinant C-type lectin-like eggshell protein in bacteria for the first time. Growth conditions were optimized and OC-17 expression was verified with anti-Histag antibody. Lastly, the model protein incorporation into synthetic calcium carbonate was studied. Because the incorporated and reconstituted protein structure is of utmost importance, the secondary and tertiary protein structures of incorporated proteins were analyzed with circular dichroism and intrinsic tryptophan fluorescence spectroscopy. The effect of both the reconstitution and incorporation were studied independently as intra-crystalline proteins could denature during the interaction with the reconstitution buffer or during the incorporation process. It was shown that the model proteins BSA, lysozyme and diphtheria anti-toxin could be reconstituted using EDTA without structural change. The incorporation was found efficient for BSA only with an efficiency of %84 in terms of total amount of protein incorporated into the crystals. The secondary structure of BSA was shown to be stable during reconstitution and incorporation. A structural change in the tertiary structure was observed in BSA. Possible improvements to incorporate a target protein as a fusion construct using the OC-17 or using the ostrich intra-crystalline peptides as ’incorporation tags’ were discussed in order to move towards a real-world application of biomimetic vaccine stabilisation

Next generation of growth-sparing techniques: preliminary clinical results of a magnetically controlled growing rod in 14 patients

Session 3A - Early Onset Scoliosis: Paper no. 33SUMMARY: Growth-sparing techniques are commonly used for the treatment of progressive EOS. The standard growing rod (GR) technique requires multiple surgeries for lengthening. The preliminary results of MCGR has shown the comparable outcomes to standard GR without the need for repeated surgery which can be expected to reduce the overall complication rate in GR surgery. INTRODUCTION: The growing rod (GR) technique for management of progressive Early-Onset Scoliosis (EOS) is a viable alternative but with a high complication rate attributed to frequent surgical lengthenings. The safety and efficacy of a non-invasive Magnetically Controlled Growing Rod (MCGR) has been previously reported in a porcine model. We are reporting the preliminary results of this technique in EOS. METHODS: Retrospective review of prospectively collected multi-center data. Only patients who underwent MCGR surgery and at least 3 subsequent spinal distractions were included in this preliminary review. Distractions were performed in clinic without anesthesia or analgesics. T1-T12 and T1-S1 height and the distraction distance inside the actuator were analyzed in addition to conventional clinical and radiographic data. RESULTS: Patients (N=14; 7 F and 7 M) had a mean age of 8y+10m (3y+6m to 12y+7m) and underwent a total of 14 index surgeries (SR: index single rod in 5 and DR: dual rod in 9) and 91 distractions. There were 5 idiopathic, 4 neuromuscular, 2 congenital, 2 syndromic and one NF. Mean follow-up (FU) was 10 months (5.8-18.2). Mean Cobb changed from 57° pre-op to 35° post-op and correction was maintained (35°) at latest FU. T1-T12 increased by 4 mm for SR and 10 mm for DR with mean monthly gain of 0.5 and 1.39, respectively. T1-S1 gain was 4 mm for SR and 17 mm for DR with mean monthly gain of 0.5 mm for SR and 2.35 mm for DR. The mean interval between index surgery and the first distraction was 66 days and thereafter was 43 days. Complications included one superficial infection in (SR), one prominent implant (DR) and minimal loss of initial distraction in three after index MCGR (all SR). Overall, partial loss of distraction was observed following 14 of the 91 distractions (one DR and 13 SR). This loss was regained in subsequent distractions. There was no neurologic deficit or implant failure. CONCLUSION: MCGR appears to be safe and provided adequate distraction similar to the standard GR technique without the need for repeated surgeries. DR patients had better initial curve correction and greater spinal height. No major complications were observed during the short follow-up period. The FDA has not cleared the drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an ‘off label’ use).postprin

Inflammation- and Cancer-Associated Neurolymphatic Remodeling and Cachexia in Pancreatic Ductal Adenocarcinoma

This work addresses two understudied elements of inflammation and malignancy—namely, (1) neurolymphatic remodeling during transitions in microenvironmental inflammatory status and (2) the systemic paraneoplastic inflammatory syndrome cancer-associated cachexia in the context of pancreatic adenocarcinoma (PDAC). Lymphatic vessels undergo dramatic phenotypic changes in initial inflammation, wound recovery, and recurrent inflammation. We identified complementary novel neuroremodeling behaviors under these conditions and hypothesized that both nerve and lymphatic remodeling were directed by a tissue remodeling factor with overlapping functions. We found that nerve growth factor (NGF) influenced not only nerves but also lymphatics. NGF stimulated lymphangiogenesis, inhibited lymphatic vessel regression during wound recovery, and increased nociception. NGF induced VEGF-C protein expression, and ablation of VEGFR-2/3 signaling abrogated NGF-mediated lymphangiogenesis, supporting a hierarchical model of NGF-VEGF signaling with NGF functioning upstream of the VEGF family. We next studied neurolymphatic remodeling in the context of malignancy using a novel murine live imaging platform. Lyve1CreERT2tdT mice inducibly express tdTomato fluorescent protein in Lyve-1+ cells. We implanted fluorescently-labeled tumor cells into cornea and pinna and identified tumor-specific neurolymphatic architecture signatures that are distinct from those associated with nonmalignant inflammation, including disorganized hypersprouting nascent lymphatic vessels and a shift in nerve morphology to a phenotype previously associated only with wound recovery. We also found that manipulating the timing of establishment of inflammation affected tumor cell persistence in tissue. In the final portion of this work, we studied cancer-associated inflammation in a broader context—i.e. the paraneoplastic syndrome cancer-associated cachexia. We sought to address discrepancies in the literature regarding cachexia gene expression with a unique set of PDAC skeletal muscle samples harvested at rapid autopsy and stratified based on severity of cachexia. We found differential expression of a number of candidate targets in PDAC samples compared to cancer-free controls including FAP-α, CAMKIIβ, FBXO32, TIE-1, and TRIM63 and challenged some previous findings. In summary, we defined a novel role for NGF signaling in lymphatics, identified microenvironment-specific neurolymphatic architecture signatures, and highlighted the complexity of cancer-associated cachexia while providing new data about this syndrome in the context of PDAC

Role of 11β-hydroxysteroid dehydrogenase type 2 in protection against inflammation during atherogenesis: studies in the Apoe-/- /11β-HSD2-/- double knockout mouse.

It is well established that atherosclerosis, an inflammatory response to chronic injury in the blood vessel wall, plays a leading role in the development and progression of cardiovascular disease. Mineralocorticoid receptor (MR) over-activation has been implicated in atherosclerosis. In mineralocorticoid-target tissues, 11β- Hydroxysteroid dehydrogenase type 2 (11β-HSD2) inactivates glucocorticoids, conferring aldosterone specificity upon the normally unselective MR. Recent evidence suggests that 11β-HSD2 may also afford protection of MR in the cells of the vasculature, providing possible mechanisms by which MR activation may directly promote atherosclerosis. Consistent with this, Apoe-/-/11β-HSD2-/- double knockout (DKO) mice show accelerated atheroma development. The present thesis tested the hypothesis that inactivation of 11β-HSD2, allowing inappropriate activation of MR in cells of the vasculature, accelerates atherogenesis through promotion of a pro-inflammatory environment with increased endothelial cell expression of adhesion molecules and subsequent macrophage infiltration into plaques. DKO mice received either the MR antagonist eplerenone (200mg/kg/day) or vehicle in normal chow diet from 2 months of age for 12 weeks. Eplerenone significantly decreased atherosclerotic burden in brachiocephalic arteries of DKO mice, an effect that was accompanied by alterations in the cellular composition of plaques such that a more stable collagen- and smooth muscle cell- rich plaque was formed. Eplerenone treatment was also associated with a reduction in vascular inflammation as demonstrated by a significant reduction in macrophage infiltration into DKO plaques. The accelerated atherogenesis in DKO mice was clearly evident by 3 months of age, a time point at which Apoe-/- mice were completely lesion free. By 6 months, some Apoe-/- mice had developed lesions whilst all DKO mice at this age showed much larger plaques. Compared to Apoe-/- mice, the cellular composition of DKO plaques was altered favouring vulnerability and inflammation, with increased macrophage and lipid content and decreased collagen content. To investigate the possible underlying mechanisms responsible for increased inflammatory cell content, the expression of vascular cell adhesion molecule 1 (VCAM-1) was compared in DKO and Apoe-/- brachiocephalic arteries. VCAM-1 immunostaining was significantly greater on the endothelial cells of DKO arteries at 3 months compared to age-matched Apoe-/- mice. At 6 months, DKO and Apoe-/- mice had similar expression of VCAM-1. Finally, mouse aortic endothelial cells (MAECs) were used to investigate the mechanism of adhesion molecule up-regulation in the absence of 11β-HSD2. Both aldosterone and TNF-α, included as a positive control, dramatically increased VCAM-1 expression in MAECs. Spironolactone pre-treatment blocked the effect of aldosterone, suggesting an MR-mediated mechanism. Corticosterone alone had no effect on VCAM-1 expression. However, inhibition of 11β-HSD2 by pre-treatment with glycyrrhetinic acid allowed corticosterone to induce a significant increase in the number of VCAM-1-stained MAECs, demonstrating functional expression of 11β- HSD2 in MAECs. Consistent with 11β-HSD2 involvement, VCAM-1 up-regulation by corticosterone in the presence of glycyrrhetinic acid was reversed by blockade of MR with spironolactone. In conclusion, loss of 11β-HSD2 activity leading to inappropriate activation of MR in atherosclerotic mice promotes plaque vulnerability and increases vascular infiltration of macrophages which accelerates plaque growth, possibly through enhanced MR- mediated endothelial cell expression of VCAM-1

Estudo sobre a produção de pasta kraft de eucalipto para novas aplicações

Most of the fluff pulp produced worldwide is used in the manufacture of absorbents, disposable diaper, intimate and non-woven products. Pre-requisites for fluff pulp are quite different from pulps produced for papermaking. Absorption capacity, absorbency rate, high specific volume (bulk), fibre length, curl and network strength are the most important properties of fluff pulp. Generally, fluff pulp is made from Bleached Softwood Kraft Pulp (BSKP) and Chemi-Thermo Mechanical Pulp (CTMP). However, the potential of Eucalyptus globulus bleached kraft pulp for such kind of applications is still uncertain. In this study, Bleached Eucalypt Kraft Pulp (BEKP) from E. globulus wood was evaluated for the fluff pulp applications and compared with properties of commercial fluff BSKP. A series of six industrial BEKPs produced from predominantly Eucalyptus globulus under variable process conditions were dry-defibrated on a pilot scale hammermill at 3500 rpm and the nonwoven air-laid fabrics evaluated for their specific volume, absorption capacity/absorption rate and the fibre network strength. The effect of non-defibrated fibre agglomerates (knots) on the former properties was evaluated. Processual variations in pulping and bleaching conditions revealed variability within 15% in the absorption capacity of fluff pulps and within 25% in the network strength of the air-laid formulations. These variations were attributed to changes in the chemical composition of BEKPs and fibre morphology. The importance of pulp bleaching sequence on the quality of BEKPs for fluff applications was highlighted. BEKPs having a high residual xylan content with a greater amount of uronic/hexenuronic moieties and coarser/deformed fibres revealed the best performance in fluff applications. The coarseness was considered a critical morphological parameter of the fibres, strongly affecting the porosity of air-laid formulations, which determined the absorption capacity and the network strength. The absorption capacity of fluffed BEKP was comparable to that of commercial softwood bleached softwood kraft pulp (BSKP), although the latter showed almost triple the network strength of air-laid formulations produced with BEKP. BSKP proved to be much more vulnerable to dry-defibration conditions than BEKP and suffered a pronounced cut of fibres, producing larger amounts of fines (dust) and stronger undesirable peeling and straightening of fibres. The same industrial Eucalyptus bleached kraft pulps (fluff pulps) were studied for the absorption properties employing dynamic water vapour sorption and contact angles measurements. The results showed that the accessibility of the fibre surface is related to the reduction of the contact angles, but, simultaneously, to the longer absorption time and less absorption capacity of the fibre network. Therefore, the absorption properties of the pulps are not necessarily directly related to their surface properties. Indeed, absorptivity is related to the surface chemical composition, fibre morphology, and fibre network structure. Thus, surface carboxylic groups promote total water uptake, resulting in better absorption capacity. Greater fibre coarseness and deformations (curl and kink) provide a less wettable surface, but a more porous network with higher specific volume, resulting in more absorbent air-laid formulations. Since multiple variables of the industrial process did not allow to unequivocally trace the relationships between the procedural conditions and the properties of the fluff cellulose, laboratory tests under controlled conditions were carried out to be better understand such relationships. Accordingly, a series of Eucalyptus globulus wood chips were cooked under the same conditions (160°C, 2h) using different active alkali charges (AA) of 13%, 15%, 17% and 18%. All pulps were further oxygen delignified (100°C, 1h) and bleached using the elemental chlorine free (ECF) and the totally chlorine free (TCF) sequences. Lab handsheets (approx. 600 g/m2) were prepared from the never dried bleached pulp and dry-defibrated in a pilot scale hammermill at different intensities (rpm) and analysed for the knots content, absorption capacity and the air-laid fibre network strength. Being dry-defibrated, pulps cooked at an increased AA revealed the reduction in knots and ECF pulps showed better defibration ability than TCF pulps. The fibre network strength was sensible to the conditions of pulping and bleaching and always increased with the increase in cooking AA. The network strength of TCF fluff pulps was from 20 to 70% greater than ECF fluff pulps. Regarding the absorption properties, BEKP fluff pulps showed good absorption capacity improved by the presence of carboxylic acid groups and the hemicelluloses removal. To enhance the absorption properties, network strength and defibration energy in fluff pulps, several chemical and physical modification were performed. For pulp modification, two commercial surfactant debonders and an antimicrobial agent (PHMB) were applied. The use of chemical additives slightly improved the water absorption capacity of pulps, being more pronounced with the application of PHMB, which increased the absorption capacity. Commercial surfactants did not promote much absorption capacity, but significantly reduced the knots contents in fluff pulps, acting essentially as debonders. These additives promoted an increase in the resistance of the fibre network and didn’t affect the morphology of cellulosic fibres. The physical modifications to promote the absorption properties were hyperbaric pressure and accelerated hornification process. Hyperbaric pressure improved not only the rate and absorption capacity of pulps, but also its specific volume and the fibre network strength. The laboratory hornified pulp showed a higher degree of hornification and a reduction in the absorption capacity than the industrially dried pulp, but the industrial hornified pulp (paper-grade) showed improvements in the absorption capacity when compared to the control pulp. The physical modifications to which the cellulose pulp was subjected improved dry defibrillation, decreasing its knot content. This reduction is more accentuated in hornified pulps than in pulps modified by hyperbaric pressure, since the removal of tightly bound water causes the fibres collapse and have less bonding capacity between the fibres. BEKPs can be considered a promising raw material for fluff applications, whose basic properties can be adjusted according to the needs by varying conditions in the pulping, bleaching and posterior treatments employing physical treatments and auxiliary chemical additives. This brings the BEKPs closer to the main properties of BSKPs..A maior parte de pasta fluff produzida mundialmente é utilizada na produção de absorventes, fraldas descartáveis, produtos íntimos e não-tecidos. Os pré requisitos para pasta fluff são bem diferentes das pastas para produção de pasta de papel. As propriedades mais importantes da pasta fluff são a capacidade e velocidade de absorção, elevado volume específico, comprimento de fibra, índice de encaracolamento e resistência de rede. Geralmente, a pasta fluff é produzida com pasta branqueada de madeira resinosa (BSKP) e pasta quimiotermomecânica (CTMP). No entanto, o potencial da madeira de Eucalyptus globulus para a produção deste tipo de pasta é incerto. Neste estudo, a pasta kraft branqueada de madeira de E. globulus (BEKP) foi avaliada para produção de pasta fluff e a pasta obtida foi comparada com as propriedades da pasta fluff (BSKP) comercial. Uma série de seis pastas industriais branqueadas predominantemente de eucalipto (BEKPs), produzidas sob condições extremas foram desfibradas, a seco, num moinho de martelos, em escala piloto, avaliadas as suas características básicas de pasta fluff, nomeadamente o seu volume específico, capacidade de absorção e velocidade de absorção e a estabilidade de rede. Foi avaliado o efeito de aglomerados de fibras não desfibrados (knots) presentes nas pastas. As variações processuais do cozimento e branqueamento revelaram uma variabilidade de 15% na capacidade de absorção das pastas fluff e cerca de 25% na estabilidade de rede. Estas variações são atribuídas às alterações na composição química e morfologia de fibras de BEKPs. Foi evidenciada a importância da sequência de branqueamento das pastas BEKPs para aplicações fluff. As BEKPs com elevado teor de xilana residual, maior quantidade de frações urónicas/hexenurónicas e fibras encaracoladas/deformadas revelaram uma melhor performance para aplicações fluff. O parâmetro coarseness foi considerado um parâmetro morfológico crítico das fibras, afetando fortemente a porosidade das formulações fluff, determinante para a capacidade de absorção e estabilidade de rede. A capacidade de absorção da pasta fluff BEKP, em comparação com a pasta comercial branqueada de fibra longa (BSKP), foi quase o dobro, embora a pasta comercial tenha apresentado cerca do triplo do resultado de estabilidade de rede determinado na formulação ao ar de pasta fluff. As pastas BSKP são mais vulneráveis às condições de desfibramento a seco em comparação com as pastas BEKP e as suas fibras sofreram um pronunciado corte, produzindo uma elevada quantidade de finos (dust) e um indesejável peeling e endireitamento de fibras. As mesmas pastas industriais kraft branqueadas de eucalipto (pastas fluff) foram estudadas para as propriedades de absorção aplicando a sorção dinâmica de vapor e medição de ângulos de contacto. Os resultados mostraram que a acessibilidade da superfície da fibra está relacionada com a redução de ângulos de contacto, mas simultaneamente ao maior tempo de absorção e menor capacidade de absorção da rede de fibra. Portanto, as propriedades de absorção das pastas não estão necessariamente relacionadas com as propriedades da superfície. De facto, a absortividade está relacionada com a composição química da superfície, morfologia da fibra e estrutura da rede de fibra. Deste modo, os grupos carboxílicos de superfície promovem a absorção total de água, resultando numa melhor capacidade de absorção. O maior coarseness e deformações da fibra (curl e kink) promovem uma superfície menos molhável, mas uma rede mais porosa, com maior volume específico, resultando em formulações mais absorventes. Tendo em consideração que as múltiplas variáveis do processo industrial não permitiram traçar de modo inequívoco as relações entre as condições processuais e as propriedades da pasta fluff, foram realizados diversos ensaios laboratoriais, em condições controladas, de forma a compreender estas relações. Deste modo, uma série de aparas de madeira ibérica E. globulus foram digeridas sob as mesmas condições (160°C, 2h), mas com diferentes cargas álcali ativo (AA) de 13%, 15%, 17% e 18%. As pastas cruas foram, posteriormente, deslenhificadas com oxigénio (100°C, 1h) e branqueadas com uma sequência de elemental chlorine free (ECF) e totally chlorine free (TCF). As folhas laboratoriais (com uma gramagem aprox. 600 g/m2) foram preparadas a partir da pasta branqueada, desfibradas a seco num moinho de martelos, a diferentes velocidades de rotação (rpm) e analisadas no teor em knots, capacidade de absorção e estabilidade de rede. Após desfibração a seco, as pastas digeridas com maior carga AA evidenciaram a redução de knots e as pastas ECF demonstraram melhor performance de desfibração em comparação com as pastas TCF. A estabilidade de rede de fibra é sensível às condições de cozimento e branqueamento e aumentam sempre com o aumento de AA. A estabilidade de rede das pastas TCF é superior em cerca de 20 a 70% em comparação com as pastas fluff ECF. As propriedades de absorção das pastas foram significativamente melhoradas pela presença dos ácidos carboxílicos e remoção de hemiceluloses. Com o objetivo de promover as propriedades de absorção, estabilidade de rede e energia de desfibração das pastas fluff foram estudadas modificações químicas e físicas. Para a modificação química foram aplicados dois surfactantes desligantes comerciais e um agente antimicrobiano (PHMB). O uso de aditivos químicos melhorou, ligeiramente, a capacidade de absorção de água das pastas,sendo mais acentuada com a aplicação do PHMB. Os surfactantes comerciais não influenciaram significativamente a capacidade de absorção, mas reduziram significativamente o teor de knots nas pastas fluff, atuando, essencialmente, como agentes desligantes no processo de desfibração a seco. Estes aditivos promoveram a estabilidade de rede e não afetaram a morfologia das fibras celulósicas. As modificações físicas avaliadas para a promoção das propriedades de absorção consistiram na pressão hiperbárica e o processo de hornificação acelerada. A pressão hiperbárica melhorou não apenas a velocidade e a capacidade de absorção das pastas, mas também o volume específico e a estabilidade de rede da fibra. A pasta hornificada laboratorialmente apresentou um maior grau de hornificação em comparação com a pasta acabada industrial, e uma redução na capacidade de absorção, contudo a pasta hornificada industrialmente (pasta acabada) apresentou melhor capacidade de absorção em comparação com a pasta de controlo (ensaio em branco). As modificações físicas a que as pastas foram submetidas facilitaram a desfibração a seco, diminuindo o teor em feixes de fibras (knots). Esta redução é mais acentuada nas pastas hornificadas do que nas pastas modificadas por pressão hiperbárica, uma vez que a remoção de água fortemente ligada provoca o colapso das fibras e tenham menor capacidade de ligação entre elas. As pastas de eucalipto BEKPs podem ser consideradas uma promissora matéria-prima para aplicações fluff, cujas propriedades básicas podem ser ajustadas de acordo com as necessidades, variando as condições dos estágios de cozimento, branqueamento e tratamentos posteriores através de modificações físicas e com aditivos químicos. Estas modificações aproximam as pastas BEKP das propriedades principais das pastas BSKP.Programa Doutoral em Engenharia Químic

A Dental Revolution? The intriguing effects of the profound social and dietary changes of the 18/19th centuries on the masticatory system

Developments in milling technology and an influx of new commodities from the 18th-19th centuries AD transformed the composition of the British diet, foreshadowing the soft hyper-nutritive diets of many 21st century populations. Jaw development is highly plastic and depends on the functional demands placed on the masticatory system, particularly during chewing. A reduction in jaw dimensions and an increase in poor occlusion among modern groups has, therefore, been attributed to the softer diet that emerged during the Industrial Revolution. Consequently, it has been hypothesised that underlying these changes are differences in masticatory behaviour when compared to pre-industrial groups. This thesis aims to test this hypothesis in order to assess whether a dental revolution, a radical transformation in masticatory behaviours, occurred in the Industrial Period. A method of 3D dental wear pattern analysis called Occlusal Fingerprint Analysis (OFA) was utilized to reconstruct masticatory behaviours from the wear facets of the molar teeth. Dental wear facets reflect the pathways of mandibular movement that occur during the chewing cycle. The facet patterns of the lower second molars of individuals from the Industrial period (n=104; 1700-1900AD) were compared to a pre-industrial sample dating to the Mediaeval and Early Post-Mediaeval periods (n=130; 1100-1700AD). Dynamic virtual simulations of the chewing stroke were also undertaken for a subset of individuals from each period (n=32). Significant differences in dental wear facet patterns between the two groups indicated that masticatory behaviours were altered in response to changing dietary composition; there was a shift to a more vertically directed chewing action as foods became softer and more heavily processed during the Industrial era. The research confirms the fundamental role food properties play in shaping mastication and, consequently, addresses the underlying mechanism responsible for the changes in occlusion and jaw morphology that have occurred over the past three centuries