Characterization of colmated wine cork stoppers

Mestrado Vinifera EuroMaster - Instituto Superior de AgronomiaThe objective of this work is to describe and compare colmated and non-colmated stoppers cork stoppers, regarding their differences in appearance (image analysis), structure (analysis with scanning electron microscopy- SEM), and mechanical behavior (compression test). For this study 75 natural cork stoppers were used and divided equally in 3 groups: (i) stoppers of superior class; (ii) stoppers of inferior class to be colmated; (iii) colmated stoppers. Image analysis techniques were applied on the surfaces of superior and inferior (pre-colmated) class of stoppers, to analyze their porosity. Porosity features showed differences between two classes: higher values of all features in the inferior class and lower in the superior quality class. Water absorption test performed on colmated and pre-colmated group of stoppers showed small differences between them: colmated stoppers absorbed less water (92.1%) than pre-colmated class (98.8%) and the same trend was found with dimensional variations (swelling) (lower swelling of colmated stoppers was reported). The behavior of the colmated and pre-colmated stoppers under compression performed in axial and radial direction was studied. Young’s modulus for compression in axial direction were 21.2 MPa and 18.4 MPa for colmated and pre-colmated group respectively, while the compression in radial direction was characterized with the range of force for the given deformation, with mean values of 147 kN and 135 kN for 1 mm deformation. Colmated stoppers were additionally analyzed by SEM, where the observations emphasis was given to the colmation material impregnation in the interior of the stoppers. Colmation material presence was mainly reported on the stoppers surface. It can be concluded that colmation process primarily improves the appearance of the stopper, covering successfully the undesirable surface pores, which is the main objective of the colmation

Diet And Dental Health In Predynastic Egypt: A Comparison Of Hierakonpolis And Naqada

Thesis (Ph.D.) University of Alaska Fairbanks, 2006Seven dietary indicators on 364 dentitions of working class Predynastic Egyptians from Hierakonpolis and Naqada are examined in this dissertation. The majority of the samples from both sites date to the Naqada 11 period (3500-3200 BC), during which these were the two main urban centers for Upper Egypt. Both sites are located on the west bank of the Nile approximately 130 km from one-another. The samples consist of adults and juveniles ranging from 6 years to over 50 years of age. The dietary indicators, which include caries, calculus, abscess, periodontal disease, macrowear, microwear, and hypoplastic enamel defects are used to look for statistically significant differences between working class inhabitants of the two sites as well as between the sex and age groups within each site. The analysis is used to address four main research questions. (1) What combination of the above indicators is the best for establishing an overall picture of diet and dental health? Results illustrate the importance of using a wide array of indictors. (2) Which of the available flora and fauna were being eaten? While each specific food could no be identified individually, cultivated items, such as wheat, barley or millet were being eaten in the form of bread, that raw vegetables were consumed by all individuals at Hierakonpolis but mostly women and children at Naqada, and that at least some meat and/or fish was consumed at both sites. (3) Were food types found as burial offerings were being eaten? Consumption of at least two burial offerings, bread and yellow nutsedge (Hierakonpolis only), are supported by the data. (4) Were the working class inhabitants of Hierakonpolis and Naqada consuming the same diet? Differences and similarities in the diet and dental health between inhabitants of the two sites are examined. While the major portions of the diet appear to be similar, this study found both dietary and behavioral differences between the working class members of these sites

The antimicrobial effect of red wine on Bacillus cereus in simulated gastrointestinal conditions

Diversos estudos têm vindo a descrever uma panóplia de efeitos benéficos na saúde humana, potencialmente atribuíveis ao consumo de vinho, incluindo efeito anti-oxidante, anti-carcinogénico, anti-inflamatório, anti-cardiovascular, assim como propriedades antimicrobianas. Este estudo foi conduzido com o objectivo de avaliar a actividade antimicrobiana do vinho sobre Bacillus cereus, células vegetativas e esporos. Os resultados apresentados neste trabalho indicam claramente, via testes in vitro, que o vinho inactiva com eficácia as células vegetativas das duas estirpes de B. cereus utilizadas. O vinho tinto inactivou as células vegetativas em fase estacionária, atingindo-se números de colónias não detectáveis (< 500 CFU mL-1), em menos de 10 s de exposição. Como tal, os ensaios de inactivação subsequentes foram efectuados com vinho diluído com água (diluição de 1:4 e 1:8). O vinho diluído 1:4 causou uma redução de 4.5 ciclos logarítmicos nas contagens de células viáveis, em 20 s de ensaio. No entanto, os esporos de B. cereus apresentaram uma elevada resistência à exposição directa ao vinho, com reduções nas contagens inferiores a 1.0 ciclo logarítmico, em 3 h. A influência de componentes do vinho (etanol, ácidos orgânicos, baixo pH e compostos fenólicos) também foi contemplada neste estudo, em células vegetativas. A combinação de ácidos orgânicos e etanol resultou numa actuação sinergética, que provocou padrões de inibição de viabilidade celular similares aos do vinho. Os compostos fenólicos testados não causaram inactivação das células (nas concentrações utilizadas). Relativamente aos resultados obtidos em condições gástricas simuladas, em contexto de refeição simulada, podemos concluir que o consumo de vinho ao longo de uma refeição pode diminuir consideravelmente o número de células de B. cereus que poderá persistir no tracto gastrointestinal. O queijo fresco pasteurizado conferiu maior protecção às células do B. cereus, quando comparado com a matriz arroz com frango. Nesta investigação também foi avaliado o comportamento de esporos de B. cereus quando submetidos a condições gastrointestinais na presença e na ausência de vinho. A presença de vinho inibe a multiplicação das células resultantes da germinação de esporos no fluido intestinal sintético, dando origem a contagens totais (células vegetativas e esporos) de B. cereus mais baixas do que na ausência de vinho. Esta tese gerou resultados que indicam que o consumo de vinho durante uma refeição conduz à redução do número de células viáveis de B. cereus no tracto gastrointestinal, assim como à diminuição do impacto da eventual germinação de esporos que pode ocorrer no intestino, reduzindo, consequentemente, o risco de infecção que o referido patogénico pode causar.Several studies describe the burgeoning health benefits of red wine consumption, including antioxidative, anti-carcinogenic, anti-inflammatory, anti-cardiovascular and antimicrobial properties. This study aimed to evaluate the antimicrobial activity of wine against Bacillus cereus vegetative cells and spores. The results of this work clearly show, via in vitro tests, that wine exerts a strong inactivation effect against vegetative cells of two B. cereus strains. The red wine tested inactivated B. cereus stationary phase vegetative cells to undetectable numbers (< 500 CFU mL-1) in less than 10 s. Thus, further inactivation assays were carried out with wine diluted with water (1:4 and 1:8). Wine diluted 1:4 caused a reduction of 4.5 log cycles on viable cell counts, in 20 s. Nevertheless, B. cereus spores were found to be highly resistant to the wine exposure, with decreases in the counts lower than 1.0 log cycles, after 3 h. The influence of wine components (ethanol, organic acids, low pH and phenolic compounds) was investigated on vegetative cells. Organic acids, when combined with ethanol, acted synergistically and conduced to a similar inhibition pattern as that of wine. The wine phenolic compounds assayed displayed no activity against the vegetative cells at the concentrations studied. Regarding data obtained in simulated gastric conditions, in a simulated meal context, we can conclude that the ingestion of wine during a meal diminishes considerably the number of B. cereus cells persisting in the alimentary tract. Pasteurized fresh cheese was found to be more protective to the cells than the chicken-rice matrix. We also evaluated the behavior of B. cereus spores under gastrointestinal conditions. In a consumption-like scenario, the treatment SGF (synthetic gastric fluid)- SIF (synthetic intestinal fluid) +Food+Wine, when compared to the system SGF-SIF+Food+Water, led to lower total counts of B. cereus in the intestine, showing that wine inhibits the multiplication of the cells obtained from the germination of spores. This work provides evidence that drinking wine with meals leads to a reduction of the number of viable cells of B. cereus and reduces the impact of the germination of spores that may occur in the small intestine, thus lowering the risk of infection the aforementioned pathogen may cause

Evaluation of the therapeutic potential of red clover extract and red grape seed extract on human adult malignant brain tumours in vitro

Gliomas are rare intrinsic brain tumours which account for 2% of all cancers. Glioblastoma multiforme is the most malignant malignant glioma form and remains incurable. The biological features which preclude successful therapy include heterogeneity, diffuse invasive patterns and angiogenesis. Despite, advances in current conventional treatments the median survival time is only 14 months. Hence there is a need to investigate novel therapeutic approaches which can be included alongside conventional treatment. One such approach is the use of micronutrients in the management of glioblastoma multiforme. This study evaluated the affects of two micronutrient extracts, red clover extract (RCE) and red grape seed extract (RGSE), on human adult malignant brain tumours in vitro. Four primary (or short-term) cell cultures derived from human brain tumour biopsies, an established cell line and normal human brain cells from an epileptic pateint were used to measure the cell viability, anti-invasive, anti-angiogenic and pro-apoptotic potentials, following 48-hour treatment with the IC50s of either micronutrient extract. Both RCE and RGSE exhibited similar affects on the glioma cell cultures. They both appeared to reduce cell viability, invasive potential and angiogenesis potential though did not appear to have any significant affect on the apoptotic portential of the glioma cultures. For example, incubation with 0.007-1ug/ml RCE caused a significant (p<0.05) reduction of in viability of glioma cells but did not affect viability of normal astrocytes. Similar results were obtained for RGSE. These doses also resulted in a significant decrease in invasion and angiogenesis (p<0.05). Effects varied between cell lines but in general decreased by 50-60%. This suggests that both RCE and RGSE do affect the development of glioma cell cultures in vitro and warrant further study into the pathways in which this may occur

Investigation of UV and IR Laser Processing of Single- Crystalline 4H:SiC and Characterisation of Laser Grown Graphene Derivatives

The formation of graphene (G) on the surface of silicon carbide (SiC) has gathered interest over recent years as a potential component in high power nano and microdevices. However, it is still in the early stages of research, therefore there are many challenges to overcome. Among the existing problems, the formation of good quality graphene/SiC is one of the most critical factors that determine the behaviour of this heterostructure. Here we report a full study of the formation of graphene and its derivative structures on SiC using different laser systems with different controlled irradiation conditions.Laser ablation experiments on polished 4H-SiC wafers using a 193 nm ArF laser over a fluence range of 0.3Jcm−2–5Jcm−2 are reported. An onset of material modification was measured at a laser fluence of 925 ± 80 mJcm−2, and a concomitant etch rate of ∼200 pm per pulse. Laser ablation sites have been analysed using optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman microscopy and white light interferometry (WLI). Different surface modifications were observed. The influences of the laser fluence, number of pulses, and scanning velocity on the position of the microchannel are discussed. At a laser fluence in the region of 1.0 Jcm−2, the irradiated site removed material forming a uniform crater. At a higher laser fluence, in the region of 2.7 Jcm−2, nodule-like structures form on the base of the ablation crater. An increased fluence led to a smoother surface with higher etched depth and ripple formation. The dissociation of laser irradiated 4H-SiC was discussed. Graphene oxide (GO) and reduced graphene oxide (rGO) formed on the SiC surface by 193 nm laser- induced high-temperature thermal decomposition of the SiC substrate. The decomposition resulted in the presence of silicon (Si), especially on the edge of the irradiated site.Graphene formation on the 4H:SiC surface by high power CO2 laser. Two distinct ablation threshold energies of 4.3 mJ and 73 mJ were found. The etch rate was dependent on the applied pulse duration, laser power, the scanning velocity and the number of pulses. High temperature thermal decomposition of the SiC substrate was achieved with a CO2 laser over a power range of 1-30 W. The structure was different from the structure obtained from the UV laser irradiated samples. More rough surfaces were prepared with small islands of graphene, GO and rGO on SiC in addition to the ripples. Monolayer and Multilayer graphene was also achieved. The laser-induced surface decomposition of the SiC was controlled spatially. The processing was held at room temperature, and the operation carried out in either a vacuum chamber or at atmospheric pressure. A fast graphene growth rate was achieved. This method is achievable, scalable and compatible with semiconductors technology due to the onsite direct writing of graphitic structure formed by the laser. This method is cost-effective as it does not necessitate SiC pre- treatment, there is no need for a processing vacuum chamber, and it can be achieved on the nano/microsecond time scale.Analytical and Finite element simulations using COMSOLTM MetaphySiCs, 5.3 have been used to calculate laser-induced temperature rise of 4H-SiC as a function of laser fluence. The simulated temperature was always less the temperature anticipated analytically. The 193 nm laser fluence required to reach the melting points of silicon, silicon carbide, and carbon, have been calculated and correspond to ∼0.97, 1.95 and 2.6 Jcm−2, respectively. Extreme heating and cooling rates controlled the growing process of graphene and its derivatives. The CO2 laser-induced temperature rise was also estimated. The CO2 laser acted as a heat source for the SiC. High power was used to reach the high temperature needed to decompose the SiC. Pulse duration also played a significant role in controlling the temperature and the depth distribution inside the SiC.This work reports the graphene formation on the surface of SiC by laser-induced thermal decomposition for electrical characterisation. Current-voltage (I-V) measurements show a decrease of the electrical resistance per unit length by nine orders of magnitude. The lowest resistance per unit length was obtained using a laser fluence of ~1.5 Jcm-2, a pulse repetition frequency of 10 Hz and using a sample translation speed of 0.01 mms-1. Temperature simulations have been performed using the finite element method (FEM) to assist in understanding the dissociation mechanisms of SiC and hence optimise the experimental variables. 2D axis-symmetric FEM calculations predict a surface temperature of ~2500K at a laser fluence of 1.5 Jcm-2. Laser-irradiated 4H:SiC is an efficient and controllable method of producing highly reproducible electrically conducting tracks. An increase in the conductivity was observed when the graphitic structure was produced with the CO2 laser. However, the conductivity was less than the graphitic structure produced by the 193 nm laser. It is expected that the different graphene interfaces, including Ohmic contact and Schottky contact, was created

Microbiology for Allied Health Students

This open textbook is a remix of Openstax Microbiology, CC-BY 4.0, and created through an Affordable Learning Georgia Round Six Textbook Transformation Grant. The textbook has the following supplemental materials within this repository: This is a collection of instructional materials for the following open textbook and lab manual: Microbiology for Allied Health Students Lab Manual Microbiology for Allied Health Students Instructional Materials Authors\u27 Description: Microbiology for Allied Health Students is designed to cover the scope and sequence requirements for the single semester Microbiology course for non-majors and allied health students. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of Microbiology for Allied Health Students make the material interesting and accessible to students while maintaining the career-application focus and scientific rigor inherent in the subject matter. The scope and sequence of Microbiology for Allied Health Students has been developed and vetted with input from numerous instructors at institutions across the U.S. It is designed to meet the needs of most microbiology courses allied health students. With these objectives in mind, the content of this textbook has been arranged in a logical progression from fundamental to more advanced concepts. The opening chapters present an overview of the discipline, with individual chapters focusing on cellular biology as well as each of the different types of microorganisms and the various means by which we can control and combat microbial growth. The focus turns to microbial pathogenicity, emphasizing how interactions between microbes and the human immune system contribute to human health and disease. The last several chapters of the text provide a survey of medical microbiology, presenting the characteristics of microbial diseases organized by body system. Accessible files with optical character recognition (OCR) and auto-tagging provided by the Center for Inclusive Design and Innovation.https://oer.galileo.usg.edu/biology-textbooks/1015/thumbnail.jp

Novel nanomaterials for lab on chip devices development: application to food system and their effect on the oxidative stress in cell cultures

This Doctoral Thesis has been formed in two well-defined areas within the field of design and development of electrochemical sensors, using nanomaterials with high analytical performance in terms of sensitivity, selectivity and reproducibility. On the one hand, the properties of transition metal chalcogenides as new nanomaterials were explored with the aim of developing new high-performance electrochemical sensors. The transition metal chalcogenides are formed by triatomic sheets with the general formula MX2, where M is a transition metal and X is a chalcogenide (S, Se or Te) and where, in turn, M is arranged in a plane surrounded by two others of X linked by covalent bonds. Each of these sheets is held by Van der Waarls forces, facilitating their exfoliation in individual layers by simple methods. First, the ultrasound-assisted exfoliation of transition metals of group VI (MoS2, WS2, MoSe2 and WSe2) was carried out. Subsequently, they were characterized by scanning electron microscopy, Raman spectroscopy, and electrochemical techniques. Next, the electrocatalytic properties of these nanomaterials in the oxidation of polyphenolic compounds, chosen for this purpose for their high antioxidant capacity, were studied. These nanomaterials demonstrated excellent resistance to sensor passivation, one of the limiting factors in the application of electrochemical techniques in the analysis of complex samples. Ultimately, its analytical application to the determination of endogenous polyphenolic compounds in complex food matrices was demonstrated. On the other hand, electrochemical sensors were developed for the in-situ detection of hydrogen peroxide in cell cultures as a marker of oxidative stress. To this end, electrodes based on high-performance nanomaterials were designed and developed aimed at electrochemical sensitivity and selectivity (Carbon Black and Prussian Blue) for the selective detection and quantification of hydrogen peroxide in a cellular model of Parkison's disease. Likewise, an on-chip platform with similar analytical performance was developed to develop cell cultures, detect hydrogen peroxide under conditions of oxidative stress, as well as evaluate the antioxidant effect of exogenous polyphenolic compounds on oxidative stress levels

Novel nanomaterials for lab on chip devices development: application to food system and their effect on the oxidative stress in cell cultures

Esta Tesis Doctoral se ha configurado en dos áreas bien definidas dentro del ámbito del diseño y desarrollo de sensores electroquímicos, empleando nanomateriales con altas prestaciones analíticas en términos de sensibilidad, selectividad y reproducibilidad. Por una parte, se exploraron las propiedades de los calcogenuros de metales de transición como nuevos nanomateriales con el objetivo de desarrollar nuevos sensores electroquímicos de altas prestaciones. Los calcogenuros de metales de transición están formados por láminas triatómicas con fórmula general MX2, donde M es un metal de transición y X un calcogenuro (S, Se o Te) y donde a su vez M se dispone en un plano rodeado por otros dos de X unidos mediante enlaces covalentes. Cada una de estas láminas se encuentran unidas mediante fuerzas de Van der Waarls, facilitando su exfoliación en capas individuales mediante métodos sencillos. En primer lugar, se llevó a cabo la exfoliación asistida por ultrasonidos de metales de transición del grupo VI (MoS2, WS2, MoSe2 y WSe2). Posteriormente, se caracterizaron mediante microscopía electrónica de barrido, espectroscopía Raman y técnicas electroquímicas. Seguidamente, se estudiaron las capacidades electrocatalíticas de estos nanomateriales en la oxidación de compuestos polifenólicos, elegidos para tal fin por su elevada capacidad antioxidante. Estos nanomateriales, demostraron una excelente resistencia a la pasivación del sensor, uno de los factores limitantes de la aplicación de las técnicas electroquímicas en el análisis de muestras complejas, constituyendo este hallazgo uno de los resultados más relevantes obtenidos. En último término, se demostró su aplicación analítica a la determinación de compuestos polifenólicos endógenos en matrices complejas de alimentos. Por otra parte, se desarrollaron sensores electroquímicos para la detección in-situ de peróxido de hidrógeno en cultivos celulares como marcador de estrés oxidativo. Para ello, se diseñaron y desarrollaron electrodos basados en nanomateriales de altas prestaciones dirigidos a la sensibilidad y selectividad electroquímicas (Carbon Black y Prussian Blue) para la detección y cuantificación selectiva de peróxido de hidrógeno en un modelo celular de enfermedad de Parkison. Asimismo, se desarrolló una plataforma on-chip con prestaciones analíticas similares para desarrollar cultivos celulares, detectar peróxido de hidrógeno en condiciones de estrés oxidativo, así como evaluar el efecto antioxidante de compuestos polifenólicos exógenos en los niveles de estrés oxidativo

The Manufacture of Official Roman Silver Coinage and Blanks Between AD193 and AD270

This thesis addresses the lack of microstructural data for Roman silver coins which has impeded our understanding of the methods used in their manufacture. In particular, many questions remain about the silvering technologies used to conceal the debased nature of Roman silver minted in the third century AD. Previous investigations into Roman silver coinage have focused on determining episodes of debasement by identifying the fineness and weights of different issues and precise elemental profiles can now be achieved using minimally destructive techniques. Comparatively, few studies have looked at the methods used to manufacture the coins. Destructive microstructural analysis is often necessary to establish the minting technologies employed by ancient moneyers. Since ancient coins are precious objects with both intrinsic and cultural value, they are often subject to strict sampling regulations. The limited access to coins for destructive analysis is the main reason for the shortage of microstructural data for Roman silver coins. For this investigation, a group of 36 Roman silver coins, minted between AD193 and AD270, were investigated using optical microscopy (OM) and scanning electron microscopy (SEM). Complementary elemental data were acquired using energy dispersive spectroscopy (EDS) and mass plasma atomic emission spectroscopy (MP-AES). Experiments were carried out to explore specific aspects of the minting process related to the different potential silvering technologies. The blanks created in the experimental castings provided microstructural data, acquired under controlled conditions, which were then compared to the ancient examples. The study revealed that silver-copper alloy blanks were artificially enriched using repetitive cycles of oxidation and blanching. Inverse segregation of the silver-rich eutectic phase was found to play no role in artificially enriching the surfaces of silver-copper alloy blanks. The investigation found that the surfaces of later quaternary alloy blanks introduced sometime between Valerian and Gallienus joint reign (AD253-260) and Gallienus sole reign (AD260-268), were artificially enhanced by a direct form of enrichment. The exudation of these white-metals creates a white-metal coating. A comparison of the ancient quaternary alloy coins and the experimental blanks revealed many shared microstructural features characteristic of direct enrichment. The evidence put forward in this thesis delivers an answer to this long-standing question. The application of heat to a cast quaternary alloy blank promotes segregation of the silver, tin and lead to the surface

Cellulose Nanocrystal Aqueous Inks Evaluated for Printed Electronics and Application to Thin-film Transistors

With increasing demand for smart features on consumer items, it is imperative that a new class of environmentally sustainable processing methods and materials are developed in order to enable smart functionality on mass produced goods. The challenge faced is to find a suitable material system and process that is bio-sourced, degradable, and compatible with novel substrates for electronics, such as flexible paper and plastic, which are often sensitive to processing conditions. We have demonstrated significant first steps towards this goal through development of conductive, aqueous-based inks of cellulose nanocrystal (CNC) for low-waste additive deposition via inkjet printing. Aqueous CNC dispersions were tuned for printability through addition of ethanol and ethylene glycol before successful patterning unto amorphous silicon (a-Si:H) thin-film transistors (TFTs) as proof-of-concept source and drain contacts. Bio-mass-sourced CNC nanoparticles functionalized with conductive polypyrrole polymer (CNC-PVP-PPY) through oxidative polymerization in water were found to withstand temperatures of 150°C and displayed conductivity as high as 77.8 S/m, making this ink a viable candidate to replace conventional polymeric conductors such as PEDOT, which are expensive to produce and require organic solvents and strict processing conditions. Two key observations were made: TFTs fabricated with CNC-PVP-PPY successfully showed switching behaviour with typical mobilities on the order of 0.2 cm^2/Vs, on-off ratio of 10^6, threshold voltage of 7.6V, and subthreshold swing of 264 mV/dec, however, the larger contact resistance for CNC-PVP-PPY had an impact on the extracted parameters when compared to sputtered metal and printed annealed-silver nanoparticle contact devices. In this work we report the first instance of conductive CNC nanoparticles successfully print-processed from aqueous inks and integrated into a-Si:H TFTs as proof of concept for the use of CNC inks in electronic devices