Photostructuring of naturally derived resins employing dynamic projection lythography

Photostructuring of Naturally Derived Resins Employing Dynamic Projection Lithograph

Multiscale structuring: investigation of localization and nonlinearity of photopolymerization by varying radiation exposure parameters.

Optical three-dimensional printing (O3DP) is an additive manufacturing technology when a material exposed to light solidifies. Using various light sources – continuous and pulsed – we can achieve different types of light absorption in the material: linear and non-linear absorption. This allows the production of 3D objects with dimensions ranging within 8 orders of magnitude: from hundreds of nanometers to centimeters. Therefore, O3DP has a wide field of applications: from prototyping and small-scale production to the production of micro-optics components, photonics, formation of structures with metamaterial properties, medicine, and tissue engineering. In the dissertation, research was focused on the size of the area of the material exposed to light and manufacturing characteristics. A study of the lateral and longitudinal dimensions of the produced spatial pixels – voxels – was performed depending on the wavelength and pulse duration. The effective degree of absorption was estimated from these data. It was also determined how the polymerization and optical breakdown thresholds change and how this affects the choice of fabrication parameters. Fabrication conditions were investigated in material without photoinitiator using a non-amplified pulse laser system (high repetition rate). A lot of attention has also been paid to the application of plant-derived materials, using linear and nonlinear absorption, and thus demonstrating multiscale O3DP. The results of this thesis showed that to achieve the desired production performance and the size of the manufactured items, it is important not only to modify the properties of the material, but also to be able to widely adjust the parameters of the equipment

Linking employee-organization value fit with job satisfaction and performance assessment

Sėkmingas darbuotojo darbas bei efektyvi organizacijos veikla priklauso nuo darbuotojo ir organizacijos atitikimo. Darbuotojo ir organizacijos atitikimas pasireiškia per vertybių suderinamumą, kuris siejamas su darbu susijusiomis pasekmėmis: pasitenkinimu darbu bei darbo atlikimo vertinimu. Darbuotojai, kuriems būdingas asmens ir organizacijos vertybių suderinamumas, yra labiau patenkinti darbu bei geriau vertinamas jų darbas. Tyrimo tikslas - nustatyti darbuotojų bei organizacijos vertybių suderinamumo ryšį su pasitenkinimu darbu bei darbuotojų darbo atlikimo vertinimu. Tyrime naudotas autoriaus modifikuotas Rokeach (1973) vertybių klausimynas, Spector pasitenkinimo darbu klausimynas ir „DnbNord“ banko darbo atlikimo vertinimo metodika. Tyrime dalyvavo 144 Vilniaus mieste įsikūrusio „DnbNord“ banko skirtingas pareigas užimantys darbuotojai (vyrai N = 34 ir moterys N = 110). Rezultatai parodė, kad darbuotojai subjektyviai vertindami vertybes skirtingose sociodemografinėse grupėse išskiria nevienodas svarbiausias ir mažiau svarbias darbuotojų ir organizacijos vertybės. Bendras visų 20 vertybių suderinamumas tarp darbuotojų ir organizacijos nėra statistiškai reikšmingas. Atskirai kiekvienos vertybės suderinamumas tarp darbuotojų ir organizacijos būdingas 8 vertybėms iš 20. Darbo stažas organizacijoje neturi ryšio su vertybių suderinamumu. Darbuotojams, kurių pasitenkinimas darbu yra aukštas, būdingas vertybių suderinamumas. Taip pat darbuotojo ir organizacijos vertybių suderinamumas būdingas darbuotojams, kurių darbo atlikimo vertinimas yra puikus.Both employee success and efficient organizational performance depend on the employee-organization fit. This fit is manifested through value compatibility, which is related to job-related outcomes: job satisfaction and performance assessment. Employees whose values are compatible with those of the organization they are a part of, display higher job satisfaction and higher performance assessment results. The research goal is determining a link between employee-organization value fit and job satisfaction as well as employee performance assessment. The research employed the value questionnaire by Rokeach (1973) modified by the author, the Spector job satisfaction questionnaire, and performance assessment methods used by DnbNord bank. The research involved 144 DnbNord bank employees of various positions based in Vilnius (male N = 34 and female N = 110). The results show that while subjectively assessing the values, employees of different socio-demographic groups focus on different key and minor values of employees and an organization. Universal employee-organization fit of all 20 values is not statistically significant. Regarding each value separately, the employee-organization fit is characteristic of 8 values out of 20. Length of service in the organization shows no correlation with the value fit. Employees with high job satisfaction also display the value fit. In addition, the employee-organization value fit is characteristic of employees who have excellent performance assessment results.Vytauto Didžiojo universiteta

Estudo do desenvolvimento de barra dietetica de cereais e goiaba desidratada pelo processo de osmose a vacuo com utilização de frutooligossacarideo

Orientador: Nelson Horacio Pezoa GarciaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: o objetivo deste trabalho foi desenvolver uma barra de fruta e cereais dietética, sem adição de açúcares calóricos convencionais nem de gordura, utilizando frutooligossacarídeo como fonte de fibra solúvel em substituição à parte dos açúcares e da gordura. A fim de determinar a melhor opção para a desidratação da goiaba utilizada na barra, foram estudados os métodos combinados de desidratação osmótica a pressão ambiente e sob vácuo, seguidos de secagem em estufa com circulação ar quente, ou em liofilizador. De acordo ao planejamento experimental utilizado, as melhores condições obtidas de tratamento osmótico para a goiaba, utilizando solução de sorbitol 65%, foram temperatura na faixa de 27,4 a 32°C e tempo de processamento de 90 a 110min. Nestas condições pode ser obtida uma incorporação de sólidos (15) de 7,9% e perda de umidade (PU) de 33%. As condições efetivas de processamento para obtenção da fruta desidratada para formular a barra, considerando que a incorporação de sólidos (15) na goiaba (sorbitol) não seria um grande obstáculo para a formulação do produto final, foram temperatura de 30°C e tempo de 120min. A incorporação de sólidos (15) nestas condições foi de 16,4% e a perda de umidade (PU) de 39,8%. A tecnologia de desidratação osmótica a vácuo possibilitou boa eficiência em baixas temperaturas, obtendo boa qualidade das frutas desidratadas, tornando-se assim uma alternativa promissora como forma de conservação de alimentos e na produção de desidratados nutricionais de boa qualidade sensorial. O melhor processo de secagem da goiaba a ser utilizada como ingrediente da barra de fruta e cereais, determinada através de análise sensorial, foi a combinação da desidratação osmótica à vácuo com a secagem em estufa por ar quente. Após testar três produtos formulados com 20, 30 e 40% de goiaba desidratada, a análise sensorial mostrou preferência pela barra que continha 30%de fruta. As barras de fruta e cereais processadas foram avaliadas periodicamente, a fim de se estudar a estabilidade microbiológica, teor de umidade, teor de ácido ascórbico (vitamina C), as características sensoriais da amostra e a intenção de compra dos consumidores no decorrer do estudo da vida de prateleira. O produto desenvolvido neste trabalho, mostrou-se estável nas avaliações microbiológicas realizadas e também com relação ao teor de umidade e ácido ascórbico, após 60 dias, que foi o tempo estudado. Os resultados obtidos na análise sensorial durante o estudo da vida de prateleira, nos mostraram que não houve diferença significativa entre as amostras no decorrer dos tempos O,30 e 60 dias, a um intervalo de segurança de 95%. Com relação a intenção de compra após os 60 dias, 90% dos provadores mostraram interesse de compra pela amostra.Abstract: This work aims at developing a Diet Cereal Bar without the additional of conventional caloric sugars, or fat by using fructoligosacharide as a soluble fiber source, replacing part of the sugar and fat. Combine processing methods were studied to determine the best way to dehydrate Guava for the diet fruit and cereal bar being: osmotic dehydration under atmosphere pressure and vacuum, followed by a drying process in an stove with air circulation or freeze dryer. According to the experimental plan, the best obtained condition for the osmotic treatment for the Guava was to use 65% sorbitol solution, with a range temperature from 27.4 to 32°C, and processing time from 90 to 110min. Under such conditions, a solid incorporation of 7.9% occurred with a moisture loss by 33%. Considering this solids incorporation (sorbitol) it would not be a significant barrier to the formulation of the final product, the effective processing conditions to obtain the dehydrated fruit were fixed at 30°C temperature and 120min time. Under these conditions, the solids incorporation was 16.4% and moisture loss 39.8%. The vacuum osmotic dehydration technology made possible to use low temperatures, assuring good quality of the dehydrated fruit, being a promising alternative to preserve food and produce dehydrated food with good sensory and nutritional quality. The sensory analysis of the diet fruit and cereal bar obtained showed that the best Guava drying process was the combination of vacuum osmotic dehydration without air stove drying. After trying 3 different formulated products with 20, 30 and 40% of dehydrated Guava, the sensory analysis indicated 30% of dehydrated Guava diet bar as the best. The final products were periodically evaluated in order to define the microbiological stability, moisture content, ascorbic acid content (Vitamin C), the sensorial characteristics and customer's buying intention during the shelf-life study. The product developed in this assignment showed microbiological stability for 60 days, as well the moisture and ascorbic acid contents. The results of the sensory analyses during the shelf-life showed no significant difference among the samples at O, 30 and 60 days, with an 95%-safety. 90% of the customers showed interest in buying the productMestradoMestre em Tecnologia de Alimento

Photoinitiator Free Resins Composed of Plant-Derived Monomers for the Optical µ-3D Printing of Thermosets

In this study, acrylated epoxidized soybean oil (AESO) and mixtures of AESO and vanillin dimethacrylate (VDM) or vanillin diacrylate (VDA) were investigated as photosensitive resins for optical 3D printing without any photoinitiator and solvent. The study of photocross-linking kinetics by real-time photorheometry revealed the higher rate of photocross-linking of pure AESO than that of AESO with VDM or VDA. Through the higher yield of the insoluble fraction, better thermal and mechanical properties were obtained for the pure AESO polymer. Here, for the first time, we validate that pure AESO and mixtures of AESO and VDM can be used for 3D microstructuring by employing direct laser writing lithography technique. The smallest achieved spatial features are 1 µm with a throughput in 6900 voxels per second is obtained. The plant-derived resins were laser polymerized using ultrashort pulses by multiphoton absorption and avalanche induced cross-linking without the usage of any photoinitiator. This advances the light-based additive manufacturing towards the 3D processing of pure cross-linkable renewable materials

Vanillin derivatives as resins for optical 3D printing

3D printing, also known as additive manufacturing has drawn increasing attention globally and has made a revolutionary impact on product fabrication in such areas like food industry, textiles, architecture, medicine, and construction [1]. Polymers are widely used in our everyday life due to their diverse properties and relatively low cost; however, it is difficult to form intricate geometries from them. Additive manufacturing is a solution to create complex geometries from plastics [2]. In this study, the cross-linked polymers were obtained by free-radical photocross-linking of vanillin diacrylate and vanillin dimethacrylate using ethyl(2,4,6-trimethylbenzoyl) phenylphosphinate as photoinitiator. The chemical structure of obtained polymers was confirmed by FT-IR spectroscopy. The yield of insoluble fraction obtained after Soxhlet extraction with acetone after 24 hours was in the range of (77-96) %. The cross-linking density calculated from the real-time photorheometry storage modulus curve at the steady state was in the range of (49-7928) mol/m3. Thermal and mechanical properties of vanillin diacrylate-based and vanillin dimethacrylate-based polymer films were investigated. Real-time photorheometry was used to monitore the evolution of free-radical photocross-linking process. The tests were performed on a MCR302 rheometer from Anton Paar equipped with the plate/plate measuring system. The samples were irradiated by UV/Vis light in a wavelength range of 250-450 nm through the glass plate using UV/Vis spot curing system OmniCure S2000, Lumen Dynamics Group Inc. The sufficient amount of photoinitiator was determined by comparing compositions containing 1-5 mol.% of photoinitiator. In most cases photopolymerization was faster and more rigid polymers were obtained when 3 mol.% of ethyl(2,4,6-trimethylbenzoyl) phenylphosphinate were used. The most rigid polymers were obtained by free-radical photocross-linking of vanillin dimethacrylate, however its films were fragile. Optical printing techniques, direct laser writing and microtransfer molding, were used to produce 3D objects out of vanillin diacrylate-based photocross-linkable resin. A test to assess the optimal fabrication parameters was performed and the capability to produce 3D microporous 75 × 75 μm2 woodpile structures out of the resin via direct laser writing was demonstrated. 3D printed objects of vanillin diacrylate-based resin with 3 mol.% of ethyl(2,4,6-trimethylbenzoyl) phenylphosphinate corresponded to the used 3D model

Molecular changes in endometrium origin stromal cells during initiation of cardiomyogenic differentiation induced with Decitabine, Angiotensin II and TGF- β1

Abstract Stem cells’ differentiation toward cardiac lineage is a complex process dependent on various alterations in molecular basis and regulation pathways. The aim of the study is to show that endometrium-derived stromal cells – menstrual, endometrial and endometriotic, could be an attractive source for examination of the mechanisms underlying cardiomyogenesis. After treatment with Decitabine, Angiotensin II and TGF-β1, cells demonstrated morphological dedifferentiation into early cardiomyocyte-like cells and expressed CD36, CD106, CD172a typically used to sort for human pluripotent stem cell-derived cardiomyocytes. RT-qPCR revealed changed cells’ genetic profiles, as majority of cardiac lineage differentiation related genes and cardiac ion channels (calcium, sodium, potassium) coding genes were upregulated after 6 and 13 days of exposure. Additionally, analysis of expression of various signaling proteins (FOXO1, PDGFB, TGFBR1, mTOR, VEGFA, WNT4, Notch1) coding genes showed differences between cell cultures as they seem to employ distinct signaling pathways through differentiation initiation. Early stages of differentiation had biggest impact on cardiomyogenesis related proteins (Nkx-2.5, EZH2, FOXO3a, H3K9Ac) levels, as we noticed after conducting Western blot and as expected, early cardiac transcription factor Nkx-2.5 was highly expressed and localized in nucleus of differentiating cells. These findings led us to assess endometrium origin stromal cells’ potential to differentiate towards cardiomyogenic lineage and better understand the regulation of complex differentiation processes in ex vivo model systems

Thermo-responsive shape memory vanillin-based photopolymers for microtransfer molding

Novel thermo-responsive shape-memory vanillin-based photopolymers have been developed for microtransfer molding. Different mixtures of vanillin dimethacrylate with tridecyl methacrylate and 1,3-benzenedithiol have been tested as photocurable resins. The combination of the different reaction mechanisms, thiol-acrylate photopolymerization, and acrylate homopolymerization, that were tuned by changing the ratio of monomers, resulted in a wide range of the thermal and mechanical properties of the photopolymers obtained. All polymers demonstrated great shape-memory properties and were able to return to their primary shape after the temperature programming and maintain their temporary shape. The selected compositions weretested by the microtransfer molding technique and showed promising results. The developed thermo-responsive shape-memory bio-based photopolymers have great potential for forming microtransfered structures and devices applicable on non-flat surfaces

Three-dimensional non-destructive visualization of teeth enamel microcracks using X-ray micro-computed tomography

Although the topic of tooth fractures has been extensively analyzed in the dental literature, there is still insufficient information about the potential effect of enamel microcracks (EMCs) on the underlying tooth structures. For a precise examination of the extent of the damage to the tooth structure in the area of EMCs, it is necessary to carry out their volumetric [(three-dimensional (3D)] evaluation. The aim of this study was to validate an X-ray micro-computed tomography (μCT) as a technique suitable for 3D non-destructive visualization and qualitative analysis of teeth EMCs of different severity. Extracted human maxillary premolars were examined using a μCT instrument ZEISS Xradia 520 Versa. In order to separate crack, dentin, and enamel volumes a Deep Learning (DL) algorithm, part of the Dragonfly’s segmentation toolkit, was utilized. For segmentation needs we implemented Dragonfly’s pre-built UNet neural network. The scanning technique which was used made it possible to recognize and detect not only EMCs that are visible on the outer surface but also those that are buried deep inside the tooth. The 3D visualization, combined with DL assisted segmentation, enabled the evaluation of the dynamics of an EMC and precise examination of its position with respect to the dentin-enamel junction