241 |
Quantitative Measurement of Cerebral Hemodynamics During Activation of Auditory Cortex With Single- and Multi-Distance Near Infrared SpectroscopyMohammad, Penaz Parveen Sultana 29 June 2018 (has links)
Functional Near Infrared Spectroscopy (fNIRS) is a safe, low-cost, non-invasive opti-cal technique to monitor focal changes in brain activity using neurovascular coupling and measurements of local tissue oxygenation, i.e., changes in concentrations of oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (HbR)[42]. This thesis utilizes two fNIRS approaches to measure hemodynamic changes associated with functional stimulation of the human auditory cortex. The first approach, single-distance continuous wave NIRS (CW-NIRS) utilizes relatively simple instrumentation and the Modified-Beer Lambert (MBL) law to estimate activation induced changes in tissue oxygenation (∆CHbO and ∆CHbR)[17]. The second more complex approach, frequency domain NIRS (FD-NIRS), employs a photon diffusion model of light propagation through tissue to measure both baseline (CHbO and CHbR), and stimulus induced changes in oxygenated and deoxygenated hemoglobin[10]. FD-NIRS is more quantitative, but requires measurements at multiple light source-detector separations and thus its use in measuring focal changes in cerebral hemodynamics have been limited.
A commercial FD-NIRS instrument was used to measure the cerebral hemodynamics from the right auditory cortex of 9 adults (21 ± 35 years) with normal hearing, while presented with two types of auditory stimuli: a 1000 Hz Pure tone, and Broad band noise. Measured optical intensities were analyzed using both MBL and photon diffusion approaches. Oxygenated hemoglobin was found to increase by 0.351 ± 0.116 µM and 0.060 ± 0.084 µM for Pure tone and Broad band noise stimuli, when analyzed by the MBL method at the ‘best’ source-detector separation. On average (across all sources), MBL analysis estimated an increase in CHbO of 0.100±0.075 µM and 0.099±0.084 µM respectively for Pure tone and Broad band noise stimulation. In contrast, the frequency domain analysis method estimated CHbO to increase by −0.401 ± 0.384 µM and −0.031 ± 0.358 µM for Pure tone and Broad band noise stimulation respectively. These results suggest that although more quantitative, multi-distance FD-NIRS may underestimate focal changes in cerebral hemodynamics that occur due to functional activation. Potential reasons for this discrepancy, including the partial volume effect, are discussed.
|
242 |
Caracterização de leveduras não convencionais para produção de cervejas / Characterization of non-conventional yeasts for beer craftingBasso, Rafael Felipe 28 June 2019 (has links)
O crescimento do mercado de cervejas artesanais tem demandado inovações. Uma abordagem que se destaca neste contexto é o uso de leveduras não convencionais em processos controlados de fermentação. Para ter melhores resultados neste cenário é fundamental que o produtor conheça as capacidades e limitações das leveduras que serão utilizadas na produção de cervejas. Assim, este estudo teve como objetivo avaliar características fisiológicas, essenciais e complementares, de uma cepa de Brettanomyces anomalus e uma Torulaspora delbrueckii para a produção de cervejas, comparando-as com duas cepas de Saccharomyces cerevisiae já utilizadas na indústria cervejeira. Avaliou-se o perfil cromossômico das leveduras (cariotipagem), a capacidade de crescimento em diferentes substratos e fontes de carbono, bem como em diferentes concentrações de etanol e compostos de lúpulo, a capacidade de esporulação, floculação, produção de sulfeto de hidrogênio (H2S), formação de espuma e a evolução da fermentação em função do tempo. Foram observadas diferenças entre os padrões cromossômicos das quatro leveduras. A intensidade de produção de H2S foi maior para a B. anomalus (WLP640) quando comparada com T. delbrueckii (WLP603), que foi classificada com a mesma intensidade de produção da S-33 (S. cerevisiae). As duas leveduras não convencionais atenderam às características fisiológicas essenciais para fermentação de cervejas. A B. anomalus foi capaz de metabolizar diversas fontes de carbono, como glicose, frutose, sacarose, maltose, matotriose e celobiose, ao passo que a T. delbrueckii cresceu apenas em glicose, frutose e sacarose, apontando sua potencial aplicação para produção de cervejas com teor alcoólico reduzido ou seu uso em inoculações sequenciais ou co-inoculações com outras leveduras. Ambas apresentaram crescimento em teores alcoólicos de 4% e 8%, ao passo que T. delbrueckii tolerou maior concentração de compostos do lúpulo em relação à B. anomalus, que não foi capaz de crescer em meio com as maiores concentrações combinadas de álcool (8% v/v) e α-ácidos (80 mg/L). Os resultados permitem concluir que as leveduras B. anomalus e T. delbrueckii possuem potencial para a produção de cervejas, desde que seja observada a compatibilidade de suas características fisiológicas com a expectativa acerca das características da cerveja. / The booming in the craft beer market worldwide has demanded innovations to bring up distinctive products. An approach that stands out in this context is the use of non-conventional yeasts in controlled beer fermentation processes. To have better outcomes in this scenario, it is essential that the producer knows the capabilities and limitations of those yeasts. Thus, this study aimed to assess essential and complementary physiological traits of one strain of Brettanomyces anomalus and one of Torulaspora delbrueckii for beer brewing, comparing them with two Saccharomyces cerevisiae strains already used in commercial breweries. The characteristics assessed were chromosome profile (karyotyping technique), growth capacity in different substrates and carbon sources, as well as under different concentrations of ethanol and hop compounds, the capability of sporulation, flocculation, hydrogen sulfide (H2S) production and foam formation and, finally, the fermentation evolution pattern. Differences in the chromosomal profile were observed among the four strains. The potential for H2S production was higher for B. anomalus (WLP640) when compared to T. delbrueckii (WLP603), which had the same potential than S-33 (S. cerevisiae). Both non-conventional yeasts have met the essential physiological traits demanded to carry beer wort fermentation. B. anomalus was able to metabolize many of the assessed carbon sources, as glucose, fructose, sucrose, maltose, maltotriose and cellobiose, while the T. delbrueckii strain was able to grow only in glucose, fructose and sucrose, pointing its potential application for low alcohol beer production, as well as its use in sequential inoculations or co-inoculations with other yeasts. Both showed satisfying growth under alcohol contents of 4% and 8%. T. delbrueckii tolerated higher hop compounds concentration when compared to B. anomalus, that was unable to grow at the highest combined concentrations of ethanol (8% v/v) and α-acids (80 mg/L). The results lead to the conclusion that the yeasts B. anomalus and T. delbrueckii can be explored in beer brewing, provided that an alignment between their physiological traits and the expectations around the beer characteristics are observed.
|
243 |
Determination of character-impact odorants in hop essential oils using hyphenated techniques in gas chromatographyEyres, Graham Terence, n/a January 2007 (has links)
Hops (Humulus lupulus L.) are an indispensable component of beer, with the essential oil responsible for imparting distinctive odour and aroma characteristics to beer. However, not all character-impact odorants in hop essential oil have been identified and hop aroma in beer is still not completely understood. The composition of hop essential oil is very complex with 485 compounds currently identified in the literature, and recent research suggests that up to 1000 compounds may actually be present. Only a certain number will be present at concentrations above threshold and make a direct contribution to the odour of the oil. In addition, many important odorants are only present at trace concentrations. Gas chromatography-olfactometry (GC-O) using human assessors is the best way to locate potent odorants and facilitate their identification.
A novel methodology was developed to identify the character-impact odorants in hop essential oil samples using hyphenated techniques in gas chromatography. GC-O was used to locate odour active compounds and determine relative importance using CharmAnalysis[TM] according to the odour potency principle. Due to the chemical complexity of the samples, considerable co-elution of peaks occurs during single column gas chromatography (1DGC), making the detection and identification of character-impact odorants challenging. Therefore, comprehensive two-dimensional gas chromatography (GCxGC) combined with time-of-flight mass spectrometry (TOFMS) was used to resolve and identify compounds eluting in the odour active regions.
The methodology was developed in a case study on coriander (Coriandrum sativum) and wild coriander (Eryngium foetidum) leaf essential oils. During GC-O analysis of these samples it was recognised that odour active regions frequently coincide with several co-eluting compounds. To address this, a heart-cut multidimensional gas chromatography-olfactometry (MDGC-O) instrument was developed to resolve these 'co-eluting odour clusters' and determine the compound(s) responsible for the odour perception.
The 'spicy' character of hops is considered to be a desirable attribute in beer associated with 'noble hop aroma'. However, the compounds responsible have yet to be adequately elucidated. This character was investigated using a commercial 'Spicy' fraction of hop essential oil, selectively enriched for monoterpene and sesquiterpene alcohols. The odour active compounds in (i) the spicy fractions and (ii) the whole essential oils of four different hop varieties were compared using the presented methodology.
A compound with an intense 'woody, cedarwood' odour was determined to be a potent, character-impact odorant in all samples. This odour coincided with a complex region of the chromatogram where up to thirteen compounds were co-eluting. The peak responsible for this odour was determined by (i) correlation of peak areas with odour potency (Charm) values and (ii) MDGC-O. The compound was tentatively identified by GCxGC-TOFMS as 14-hydroxy-β-caryophyllene, which has not previously been reported as an odorant in hop essential oil. It was concluded that this compound and other 'woody, cedarwood' odorants contributed to the 'spicy' character of the investigated hop samples. Compounds previously associated with noble hop aroma, notably caryophyllene oxide, humulene epoxides I and II, and humulenol II, did not contribute to the odour character of the hop samples.
Other potent odorants that were identified in the whole essential oil and spicy fractions of hops were: geraniol, linalool, β-ionone, eugenol, isovaleric acid, and β-damascenone. While myrcene was a moderately potent odorant in the whole hop essential oil samples, the abundant sesquiterpene hydrocarbons α-humulene, β-caryophyllene and β-farnesene did not significantly contribute to the odour character.
|
244 |
The Influence of Red Blood Cell Scattering in Optical Pathways of Retinal Vessel OximetryLeBlanc, Serge E. 18 February 2011 (has links)
The ability to measure the oxygen saturation, oximetry, of retinal blood both non-invasively and in-vivo has been a goal of eye research for years. Retinal oximetry can in principle be achieved from the measurement of the reflectance spectrum of the ocular fundus. Oximetry calculations are however complicated by the scattering of red blood cells, the different pathways of light through blood and the ocular tissues that light interacts with before exiting the eye. The goal of this thesis was to investigate the influence of red blood cell scattering for different light paths relevant to retinal oximetry. Results of in-vitro whole blood experiments found calculated oxygen saturation differences between blood samples measured under different retinal light paths, and these differences did not depend on the absorbance path length. We also showed that the calculated oxygen saturation value determined by a multiple linear regression Beer-Lambert absorbance model depended on the wavelength range chosen for analysis. The wavelength dependency on the calculated oxygen saturation value is due in part to the correlation that exists between the oxyhaemoglobin and deoxyhaemoglobin extinction coefficient spectra and to errors in the assumptions built into the Beer-Lambert absorbance model. A wavelength region with low correlation between the oxyhaemoglobin and deoxyhaemoglobin extinction coefficients was found that is hypothesized to be a good range to calculate oxygen saturation using a multiple linear regression approach.
|
245 |
Den övertygande reklamen? : En analys av Pripps Blå och Norrlands Gulds reklambilderEdstam, Karin, Rogemyr, Maria January 2013 (has links)
Modern societies are generally becoming increasingly capitalist in nature and economies of these societies are thus likely to become more focused on consumer consumption. Advertising plays a vital role in contemporary society where we, as consumers and citizens, are surrounded by it everywhere we look and everywhere we go. This puts pressure on advertisers to become more creative and to explore new ways of marketing their products and services in an already saturated environment. We believe that the added pressure and the already established role of marketing in society make advertisements an interesting and telling object for analysis. This is particularly the case with regards to the concept of selling and marketing products that have qualities that are known to be less than beneficial for our health. This paper analyzes four commercial advertisements marketing beer; a product that we argue has qualities that can be seen as potentially bad for the health of individuals and for societies. The brands advertising the products, which are subject to our analysis, are Pripps Blå and Norrlands Guld. The aim was to use rhetorical and semiotic analyses to find which strategies had been employed in the advertisements to sell the above-mentioned brands, thus allowing us to study rhetorical techniques drawing on cultural conventions. Our analysis showed that each of the four advertisements in our study contained rhetorical arguments; of which a recurring argument in all of the advertisements was pathos. This was strengthened by the semiotic analysis which showed that the majority of connotations found were of an emotional character. Our conclusion is therefore that Pripps Blå and Norrlands Gulds strategy for selling their beer is to appeal to our senses and emotions rather than our logic and rationality. This strategy we believe to be founded in the cultural conventions and ideological beliefs currently existing in Swedish society.
|
246 |
The Influence of Red Blood Cell Scattering in Optical Pathways of Retinal Vessel OximetryLeBlanc, Serge E. 18 February 2011 (has links)
The ability to measure the oxygen saturation, oximetry, of retinal blood both non-invasively and in-vivo has been a goal of eye research for years. Retinal oximetry can in principle be achieved from the measurement of the reflectance spectrum of the ocular fundus. Oximetry calculations are however complicated by the scattering of red blood cells, the different pathways of light through blood and the ocular tissues that light interacts with before exiting the eye. The goal of this thesis was to investigate the influence of red blood cell scattering for different light paths relevant to retinal oximetry. Results of in-vitro whole blood experiments found calculated oxygen saturation differences between blood samples measured under different retinal light paths, and these differences did not depend on the absorbance path length. We also showed that the calculated oxygen saturation value determined by a multiple linear regression Beer-Lambert absorbance model depended on the wavelength range chosen for analysis. The wavelength dependency on the calculated oxygen saturation value is due in part to the correlation that exists between the oxyhaemoglobin and deoxyhaemoglobin extinction coefficient spectra and to errors in the assumptions built into the Beer-Lambert absorbance model. A wavelength region with low correlation between the oxyhaemoglobin and deoxyhaemoglobin extinction coefficients was found that is hypothesized to be a good range to calculate oxygen saturation using a multiple linear regression approach.
|
247 |
The analysis of competitive strategies of beer market in Taiwan -Take TTL as an exampleHuang, Kuan-Jung 28 April 2010 (has links)
Because the beer market in Taiwan had been opened up, the monopoly, Taiwan Beer, has been facing intense competition. However, state-owned Taiwan Beer uses flexible strategies to respond to these challenges and always is the leading company in the industry.
This study tried to use Game Theory to analyze the competitive strategy of Taiwan Beer in different period of time and find out the relationships between Taiwan Beer and competitor. At the beginning, this research used Game theory to describe the competition in the beer industry. Then, it used Prisoner's Dilemma, the Beach Ice Cream Selling Model, entry-deny strategies, multi-brand strategy and Co-opetition to explain Taiwan Beer¡¦s interaction with others.
Finally, this study did not see the competition as the only way that can help companies survive. When the company is thinking about how to defeat others, it also has to be thinking about how to cooperate with others to derive more advantages.
|
248 |
The feasibility study on outdoor large scale microalgae cultureCheng, Jen-hsuan 13 July 2011 (has links)
Nannochloropsis oculata is one of promising oleaginous microalga, containing a plenty of fat which can be extracted and transformed into biodiesel. The purpose of this study is to develop a closed system, Outdoor Temperature Controllable Photobioreactor System (OTCPS), to cultivate the algae in pure and massive quantity. In this research, the seawater from Sizihwan is used as the cultivation liquid. Lambert-Beer¡¦s Law is adopted to calculate the attenuation coefficient of light intensity in a water column. By adjusting the water depth, not only the light intensity but also the water temperature could be controlled at the optimal situation and thus avoids unfavorable temperature changing in harsh weather. Therefore to establish the relationship of light intensity and water temperature is critical for the success of growing microalgae in outdoor conditions.
The temperature variation of culture medium can be explained by the heat transfer theorem. In this study, the heat radiation mechanism and the first order of Fourier heat conductivity were adopted to simulate the liquid temperature change. The simulation results have shown good agreement with the filed data especially during daytime.
The experimental results reveal that the winter grow rate of Nannochloroposis oculata is 0.33 d-1 , while the summer growth rate is only 0.20 d-1 . This may imply that the high temperature is an inhibition to the growth of Nannochloroposis oculata. Besides when the cell density of microalgae is getting higher, each individual alga may create mutual shading effect and thus reduce the photosynthetic efficiency. In conclusion, the proposed photobioreactor has been successfully tested in summer, autumn, and winter at Kaohsiung, in the south of Taiwan. This indicates that this device can be broadly used in the subtropic zone
|
249 |
Growth Of Agriculturally Important Pseudomonas Spp. And Azotobacter Chroococcum On Beer Waste And Observation Of Their Survival In PeatAbat, Benek 01 September 2006 (has links) (PDF)
In this study agriculturally important Pseudomonas spp. which may solubilize phosphate and Azotobacter chroococcum which can fix atmospheric nitrogen were grown on waste beer with 4 different concentrations and conditions for best growth were determined. Having potential of use as biofertilizers, they were put in the carrier material peat and survivals of them were observed for 3 months at three different temperatures.
Biofertilizer can be defined as a substance which contains living microorganisms which, when applied to seed, plant surface, or soil, colonizes the rhizosphere or the interior of the plant and promotes growth by replacing soil nutrients or making nutrients more available or increasing plant access to nutrients.
In order to benefit from the biofertilizers, viable and active microorganisms in high numbers must be present which requires high quality inoculants. The carrier substrate is a critical part of the product formulation and must be capable of supporting high numbers of the intended microbe(s).
It was found that Pseudomonas spp. can solubilize phosphate. Furthermore, conditions for best growth for both bacteria were determined as 30 % of waste beer. Peat was found as an appropriate carrier due to preservation of viable cells for 3 months at 0 º / C, 20 º / C and 30 º / C. However, peat couldn&rsquo / t support high numbers of Pseudomonas spp. at 30 º / C.
|
250 |
Adaptation of lactic acid bacteria for growth in beer2012 August 1900 (has links)
Growth of bacteria in beer leads to turbidity and off-flavors, resulting in a spoiled and unpalatable product and thus economic loss. The most common beer-spoilage organisms (BSOs) are lactic acid bacteria (LAB), with Lactobacillus and Pediococcus species being the most problematic. Because of the harsh environment (low nutrients, antimicrobial compounds ethanol and hops, anaerobic), only select isolates are able to sustain growth in and spoil beer. To begin understanding the phenomenon of LAB adapting to overcome stresses in beer, ethanol tolerance, hop resistance, and nutrient acquisition mechanisms were investigated. First, ethanol tolerance was analyzed in the context of beer-spoilage ability, and it was found that it is intrinsically high in LAB, thus leading to the conclusion that LAB ability to spoil beer is not dependent on ethanol resistance levels. This was then followed by genome sequencing of the BSO Pediococcus claussenii ATCC BAA-344T (Pc344) to elucidate mechanisms being used to resist hops and acquire low abundance or alternative nutrients. Subsequent analysis of Pc344 and Lactobacillus brevis BSO 464 via reverse transcription quantitative PCR demonstrated the variability found among BSOs in the presence of beer-spoilage-related genes and their use during growth in beer. Further analysis of Pc344 was performed via RNA-sequencing to get a global view of gene expression during mid-logarithmic growth in beer. It was found that several alternative nutrients were being used by Pc344 to sustain growth, and that hop resistance was enabled by a variety of mechanisms including oxidative stress response and pH control. Finally, genomic comparison of BSOs determined that conservation is only present for closely related organisms and that no specific genes/proteins are indicative of an isolate’s beer-spoilage potential. It is more likely that horizontal gene transfer plays a major role in LAB adaption for growth in beer, and that plasmids are very important for this evolution, as was demonstrated by plasmid-variants of Pc344. The main conclusions of this thesis are therefore that hop resistance is the main factor determining ability to grow in beer, and that transfer of genetic elements is the driving force behind LAB evolving into BSOs.
|
Page generated in 0.1002 seconds