952 research outputs found
Lipid content and biomass analysis in autotrophic and heterotrophic algal species
Biofuels are a form of renewable energy derived from living matter, typically plants. The push for biofuels began in order to decrease the amount of carbon dioxide (CO2) released into the atmosphere, as biofuels are essentially carbon neutral. The idea is the same amount of CO2 the plants took in to perform photosynthesis will then be released in the burning of the biofuels. Algae is an excellent source of biofuels because it grows quickly and is versatile in terms of the type of fuel it can produce. The two most common mechanisms for algae growth are heterotrophic or photoautotrophic. Heterotrophically grown algae uses an exogenous energy source, such as glucose, and uses the energy stored in it to perform cellular functions. Glucose also serves as a source of carbon and hydrogen, which are the primary elements found in lipids. In addition heterotrophic algae requires other nutrients for survival, such as water, vitamins, and inorganic ions. Algae grown photoautotrophically uses pigments in cellular photoreceptors to convert energy from light into adenosine triphosphate (ATP), an energy source, and to produce glucose. It also requires water, vitamins, and inorganic ions like the heterotrophic algae does. Some algal species, such as Chlorella zofingiensis, can be grown both photoautotrophically and heterotrophically. This algae species will be the subject of our experiment.
Our experiment seeks to discover the most efficient way of growing algae to produce the highest amount of lipids. In addition to serving as a key component of cell and organelle membranes, lipids are a common form of high efficiency, long-term energy storage for living organisms, which is why lipids are extracted and processed to form biofuels. We propose growing one species of algae photoautotrophically by providing it with proper amounts of light but eliminating any glucose available. We will also grow the same species heterotrophically, with exogenous access to glucose, but eliminating all exposure to light sources. Finally, we will grow the same species mixotrophically with access to both glucose and light. Once the algae is grown, it will be harvested and analyzed for its lipid profile to determine which algae sample has the highest percent lipid content. We will also measure the percent biomass of each sample to determine which primary energy source leads to the greatest amount of total algal growth, percent organic material, and percent lipid content.
We predict the algae grown with access to both sunlight and exogenous glucose will produce both the highest lipid content and the highest percent of biomass
Requirements and test results for the qualification of thermal control coatings
Paint type coatings are often used as engineering materials in critical satellite temperature control applications. The functional features of coatings used for temperature control purposes must remain stable throughout the satellite manufacturing process and the satellite mission. The selection of a particular coating depends on matching coating characteristics to mission requirements. The use of paint coatings on satellites, although having an extensive history, requires that the paint be qualified to each application on an individual basis. Thus, the qualification process through testing serves to ensure that paint coatings as engineering materials will fulfill design requirements
Control surfaces of aquatic vertebrates: active and passive design and function
Aquatic vertebrates display a variety of control surfaces that are used for propulsion, stabilization, trim and maneuvering. Control surfaces include paired and median fins in fishes, and flippers and flukes in secondarily aquatic tetrapods. These structures initially evolved from embryonic fin folds in fishes and have been modified into complex control surfaces in derived aquatic tetrapods. Control surfaces function both actively and passively to produce torque about the center of mass by the generation of either lift or drag, or both, and thus produce vector forces to effect rectilinear locomotion, trim control and maneuvers. In addition to fins and flippers, there are other structures that act as control surfaces and enhance functionality. The entire body can act as a control surface and generate lift for stability in destabilizing flow regimes. Furthermore, control surfaces can undergo active shape change to enhance their performance, and a number of features act as secondary control structures: leading edge tubercles, wing-like canards, multiple fins in series, finlets, keels and trailing edge structures. These modifications to control surface design can alter flow to increase lift, reduce drag and enhance thrust in the case of propulsive fin-based systems in fishes and marine mammals, and are particularly interesting subjects for future research and application to engineered systems. Here, we review how modifications to control surfaces can alter flow and increase hydrodynamic performance
The potential for circular dichroism as an additional facile and sensitive method of monitoring low-molecular-weight heparins and heparinoids
The ultraviolet circular dichroism (CD) spectra of commercial low-molecular-weight heparins, heparinoids and other anticoagulant preparations have been recorded between 180 and 260 nm. Principal component analysis of the spectra allowed their differentiation into a number of groups related to the means of their production reflecting the structural changes introduced by each process. The findings suggest that CD provides a complementary technique for the rapid analysis of heparin preparations
What is the mechanism effect that links social support to coping and psychological outcome within individuals affected by prostate cancer? Real time data collection using mobile technology
Abstract Unmet support needs are prevalent in men affected by prostate cancer. Moreover, little is known about the optimal type of social support, or its mechanism effect between coping and emotional outcome in men affected by this disease to identify areas for clinical intervention. This study aimed to empirically test the propositions of social support theory in âreal timeâ within individual men living with and beyond prostate cancer. Purposeful sub-sample from a larger prospective longitudinal study of prostate cancer survivors, took part in real time data collection using mobile technology. Self-reports were collected for 31 days prompted by an audio alarm 3 times per day (a total of 93 data entries) for each of the 12 case studies. Electronic data were analysed using time series analysis. Majority of response rates were >90%. Men reported a lack of satisfaction with their support over time. Testing the propositions of social support theory âwithin individualsâ over time demonstrated different results for main effect, moderation and mediation pathways that linked coping and social support to emotional outcome. For two men, negative effects of social support were identified. For six men the propositions of social support theory did not hold considering their within-person data. This innovative study is one of the first, to demonstrate the acceptability of e-health technology in an ageing population of men affected by prostate cancer. Collectively, the case series provided mixed support for the propositions of social support theory, and demonstrates that âone size does not fit allâ
The role of synovial macrophages and macrophage-produced cytokines in driving aggrecanases, matrix metalloproteinases, and other destructive and inflammatory responses in osteoarthritis
There is an increasing body of evidence that synovitis plays a role in the progression of osteoarthritis and that overproduction of cytokines and growth factors from the inflamed synovium can influence the production of degradative enzymes and the destruction of cartilage. In this study, we investigate the role of synovial macrophages and their main proinflammatory cytokines, interleukin (IL)-1 and tumour necrosis factor-alpha (TNF-α), in driving osteoarthritis synovitis and influencing the production of other pro- and anti-inflammatory cytokines, production of matrix metalloproteinases, and expression of aggrecanases in the osteoarthritis synovium. We established a model of cultures of synovial cells from digested osteoarthritis synovium derived from patients undergoing knee or hip arthroplasties. By means of anti-CD14-conjugated magnetic beads, specific depletion of osteoarthritis synovial macrophages from these cultures could be achieved. The CD14(+)-depleted cultures no longer produced significant amounts of macrophage-derived cytokines like IL-1 and TNF-α. Interestingly, there was also significant downregulation of several cytokines, such as IL-6 and IL-8 (p < 0.001) and matrix metalloproteinases 1 and 3 (p < 0.01), produced chiefly by synovial fibroblasts. To investigate the mechanisms involved, we went on to use specific downregulation of IL-1 and/or TNF-α in these osteoarthritis cultures of synovial cells. The results indicated that neutralisation of both IL-1 and TNF-α was needed to achieve a degree of cytokine (IL-6, IL-8, and monocyte chemoattractant protein-1) and matrix metalloproteinase (1, 3, 9, and 13) inhibition, as assessed by enzyme-linked immunosorbent assay and by reverse transcription-polymerase chain reaction (RT-PCR), similar to that observed in CD14(+)-depleted cultures. Another interesting observation was that in these osteoarthritis cultures of synovial cells, IL-1ÎČ production was independent of TNF-α, in contrast to the situation in rheumatoid arthritis. Using RT-PCR, we also demonstrated that whereas the ADAMTS4 (a disintegrin and metalloprotease with thrombospondin motifs 4) aggrecanase was driven mainly by TNF-α, ADAMTS5 was not affected by neutralisation of IL-1 and/or TNF-α. These results suggest that, in the osteoarthritis synovium, both inflammatory and destructive responses are dependent largely on macrophages and that these effects are cytokine-driven through a combination of IL-1 and TNF-α
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Rajiform locomotion: three-dimensional kinematics of the pectoral fin surface during swimming in the freshwater stingray Potamotrygon orbignyi
Rajiform locomotion in fishes is dominated by distinctive undulations of expanded pectoral fins. Unlike other fishes, which typically interact with the fluid environment via multiple fins, undulating rays modulate a single control surface, the pectoral disc, to perform pelagic locomotion, maneuvering and other behaviors. Complex deformations of the broad, flexible pectoral fins occur as the undulating wave varies in three dimensions; pectoral fin kinematics and changes in waveform with swimming speed cannot be fully quantified by two-dimensional analyses of the fin margin. We present the first three-dimensional analysis of undulatory rajiform locomotion in a batoid, the freshwater stingray Potamotrygon orbignyi. Using three cameras (250framessâ1), we gathered three-dimensional excursion data from 31 points on the pectoral fin during swimming at 1.5 and 2.5disclengthssâ1, describing the propulsive wave and contrasting waveforms between swimming speeds. Only a relatively small region of the pectoral fin (~25%) undulates with significant amplitude (>0.5cm). Stingrays can maintain extreme lateral curvature of the distal fin margin in opposition to induced hydrodynamic loads, Ê»cuppingÊŒ the edge of the pectoral fin into the flow, with potential implications for drag reduction. Wave amplitude increases across both anteroposterior and mediolateral fin axes. Along the anteroposterior axis, amplitude increases until the wave reaches mid-disc and then remains constant, in contrast to angulliform patterns of continuous amplitude increase. Increases in swimming speed are driven by both wave frequency and wavespeed, though multivariate analyses reveal a secondary role for amplitude.Organismic and Evolutionary Biolog
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Hydrodynamic function of dorsal and anal fins in brook trout (Salvelinus fontinalis)
Recent kinematic and hydrodynamic studies on fish median fins have shown that dorsal fins actively produce jets with large lateral forces. Because of the location of dorsal fins above the fishâs rolling axis, these lateral forces, if unchecked, would cause fish to roll. In this paper we examine the hydrodynamics of trout anal fin function and hypothesize that anal fins, located below the fishâs rolling axis, produce similar jets to the dorsal fin and help balance rolling torques during swimming. We simultaneously quantify the wake generated by dorsal and anal fins in brook trout by swimming fish in two horizontal light sheets filmed by two synchronized high speed cameras during steady swimming and manoeuvring. Six major conclusions emerge from these experiments. First, anal fins produce lateral jets to the same side as dorsal fins, confirming the hypothesis that anal fins produce fluid jets that balance those produced by dorsal fins. Second, in contrast to previous work on sunfish, neither dorsal nor anal fins produce significant thrust during steady swimming; flow leaves the dorsal and anal fins in the form of a shear layer that rolls up into vortices similar to those seen in steady swimming of eels. Third, dorsal and anal fin lateral jets are more coincident in time than would be predicted from simple kinematic expectations; shape, heave and pitch differences between fins, and incident flow conditions may account for the differences in timing of jet shedding. Fourth, relative force and torque magnitudes of the anal fin are larger than those of the dorsal fin; force differences may be due primarily to a larger span and a more squarely shaped trailing edge of the anal fin compared to the dorsal fin; torque differences are also strongly influenced by the location of each fin relative to the fishâs centre of mass. Fifth, flow is actively modified by dorsal and anal fins resulting in complex flow patterns surrounding the caudal fin. The caudal fin does not encounter free-stream flow, but rather moves through incident flow greatly altered by the action of dorsal and anal fins. Sixth, trout anal fin function differs from dorsal fin function; although dorsal and anal fins appear to cooperate functionally, there are complex interactions between other fins and free stream perturbations that require independent dorsal and anal fin motion and torque production to maintain control of body position.Organismic and Evolutionary Biolog
On the rules for aquatic locomotion
We present unifying rules governing the efficient locomotion of swimming fish and marine mammals. Using scaling and dimensional analysis, supported by new experimental data, we show that efficient locomotion occurs when the values of the Strouhal (St) number St(=f A/U) and Aâ(=A/L), two nondimensional numbers that relate forward speed U, tail-beat amplitude A, tail-beat frequency f , and the length of the swimmer L are bound to the tight ranges of 0.2â0.4 and 0.1â0.3, respectively. The tight range of 0.2â0.4 for the St number has previously been associated with optimal thrust generation. We show that the St number alone is insufficient to achieve optimal aquatic locomotion, and an additional condition on Aâ is needed. More importantly, we show that when swimming at minimal power consumption, the Strouhal number of a cruising swimmer is predetermined solely by the shape and drag characteristics of the swimmer. We show that diverse species of fish and cetaceans cruise indeed with the St number and Aâ predicted by our theory. Our findings provide a physical explanation as to why fast aquatic swimmers cruise with a relatively constant tail-beat amplitude of approximately 20% of the body length, and their swimming speed is nearly proportional to their tail-beat frequenc
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