Synthesis and self-assembly of lipid (DMPC)-conjugated gold nanoparticles

Bio-conjugated nanomaterials play a promising role in the development of novel supramolecular structures, molecular machines, and biosensing devices. In this study, lipid-conjugated gold nanoparticles were synthesized and allowed to form a self-assembled monolayer structure. The nanoparticles were prepared by a phase transfer method, which involved the reduction of potassium tetrachloroaurate (III) by sodium citrate in an aqueous solution and the simultaneous transfer of the reduced species to an organic medium containing DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine). The gold nanoparticles were characterized using UV-Vis spectroscopy and dynamic light scattering (DLS) particle-size analysis. In addition, the resulting nanoparticles were examined using transmission electron microscopy (TEM). The Langmuir-Blodgett (LB) technique was used to assemble the DMPC-capped nanoparticles onto a water subphase at room temperature. The measurement of the compression isotherm confirmed the assemblage of lipid capped gold nanoparticles. This method of synthesis of ordered structures utilizing molecular interactions of lipids will be useful in developing novel metamaterials and nanocircuits.Comment: 7 pages, 5 Figure

Gravity, chromosomes, and organized development in aseptically cultured plant cells

The objectives of the PCR experiment are: to test the hypothesis that microgravity will in fact affect the pattern and developmental progression of embryogenically competent plant cells from one well-defined, critical stage to another; to determine the effects of microgravity in growth and differentiation of embryogenic carrot cells grown in cell culture; to determine whether microgravity or the space environment fosters an instability of the differentiated state; and to determine whether mitosis and chromosome behavior are adversely affected by microgravity. The methods employed will consist of the following: special embryogenically competent carrot cell cultures will be grown in cell culture chambers provided by NASDA; four cell culture chambers will be used to grow cells in liquid medium; two dishes (plant cell culture dishes) will be used to grow cells on a semi-solid agar support; progression to later embryonic stages will be induced in space via crew intervention and by media manipulation in the case of liquid grown cell cultures; progression to later stages in case of semi-solid cultures will not need crew intervention; embryo stages will be fixed at a specific interval (day 6) in flight only in the case of liquid-grown cultures; and some living cells and somatic embryos will be returned for continued post-flight development and 'grown-out.' These will derive from the semi-solid grown cultures

Rendimiento y características de las frutas del 'Superplátano' francés-enano evaluado en tres localidades

The French-type 'Dwarf Superplátano' (Musa AAB), a reverted clone selected from the local false horn-type 'Common Dwarf' plantain, was subjected to various bunch management treatments at three locations. The immature bunches were pruned to either three, four or five uppermost hands. Those pruned to four and five hands were either sprayed with a gibberelllc acid solution or not sprayed. Both sprayed and unsprayed bunches were immediately bagged or left unbagged. Spraying with gibberellic acid and bagging, alone or combined, had no significant effect on bunch yield components nor on fruit traits. Regardless of location, pruning significantly reduced bunch size and the time needed for fruit filling. Bunches pruned to five, four and three hands averaged 79, 66 and 50 fruits, respectively. Pruning from five to three hands significantly reduced fruit filling to 112 days. Pruning also affected bunch yield and bunch mean fruit weight, but the effect varied with location. A reduction in bunch size from five to four hands at Corozal and from four to three hands at Salinas and Yauco substantially reduced bunch yield by 12 and 23%, respectively. Bunch mean fruit weight significantly increased at the expense of reducing bunch size to three hands at Corozal and to four hands at Salinas and Yauco. Bunch mean fruit weight at Corozal was always superior to that at Yauco. Regardless of location, pruning significantly brought about an increase in fruit size in the distal hand. The thickest and largest fruits were produced in bunches pruned to three hands. Likewise, pruning significantly increased mean fruit weight in the distal hand, but the effect varied with location. At Corozal, fruits in the distal hand of bunches pruned to three hands attained the heaviest mean weight, 355 g. Regardless of location, a reduction in hands from five to four upgraded fruits in the distal hand from non-marketable to marketable by increasing their weight to over 270 g. We inferred that under intensive management the French-type 'Dwarf Superplátano' clone with the bunch pruned to four uppermost hands has the potential to yield 173,000 fruits per hectare, equivalent to 57.6 t of fruits per hectare. These fruits conform to the local marketing standards established for the 'Maricongo' plantain.El 'Superplátano' tipo francés-enano (Musa AAB), una selección clonal del plátano local 'Enano-Común' tipo cuerno, se sometió a varios tratamientos de manejo del racimo en tres localidades. Dos semanas después de emerger los racimos tiernos, estos se podaron hasta dejar las tres, cuatro o cinco manos superiores del racimo. Algunos de los racimos podados a cuatro y cinco manos se asperjaron con una solución de ácido giberélico mientras que otros se dejaron sin asperjar. Algunos de los racimos asperjados y sin asperjar se enfundaron con bolsas de polietileno y otros se dejaron sin enfundar. Los tratamientos con el regulador de crecimiento y el enfundado, solos o combinados, no tuvieron efectos significativos sobre los componentes de rendimiento y las características de las frutas. Irrespectivo de la localidad, la poda redujo significativamente el tamaño del racimo y los días necesarios para el engorde de las frutas. Los racimos podados a cinco, cuatro y tres manos promediaron 79, 66 y 50 frutas, respectivamente. La poda a tres manos redujo el tiempo de engorde de las frutas a 112 días. La poda también afectó el peso del racimo y el peso medio de las frutas en el racimo pero el efecto varió por localidad. La reducción en el tamaño del racimo de cinco a cuatro manos en Corozal y de cuatro a tres manos en Salinas y Yauco redujo sustancialmente el rendimiento en 12 y 23%, respectivamente. El peso medio de todas las frutas en el racimo aumentó significativamente a expensas de la reducción en el tamaño del racimo a tres manos en Corozal y a cuatro manos en Salinas y Yauco. El peso medio de las frutas en Corozal fue siempre superior al obtenido en Yauco.  Irrespectivo de la localidad, la poda incrementó significativamente el tamaño de las frutas en la última mano del racimo. Las frutas de mayor grosor y largo se produjeron en los racimos podados a tres manos, igualmente, la poda aumentó sustancialmente el peso medio de las frutas en la última mano pero el efecto dependió de la localidad. En Corozal las frutas en la última mano de los racimos podados a tres manos alcanzaron el mayor peso promediando 355 g. Irrespectivo de la localidad, la reducción en el tamaño del racimo de cinco a cuatro manos promovió la clasificación de las frutas en la última mano de no mercadeables a mercadeables al adquirir un peso mayor a los 270 g. inferimos que bajo manejo intensivo el clon Superplátano francés-enano con el racimo podado a cuatro manos superiores tiene el potencial de producir 173,000 frutas mercadeables por hectárea, equivalente a 57.6 t de frutas por hectárea. Estas frutas cumplen con los requisitos locales de mercadeo establecidos para el plátano 'Maricongo'

Life: Origin and evolution on Earth--How can we escape?

Exploitation of gene regulation rather than the creation of new genes has been predominantly responsible for the evolutionary advances in animals and plants that are widely recognized today. Until very recently it was not possible to examine life in the absence of gravity. We can now imagine forms of life in the universe adapting to circumstances different from those found on Earth. Our own life forms would surely become different in time if they were transferred to other planets with different conditions, including much lower or higher gravity

Nutrient Considerations for Plants Grown Under Space Flight Conditions

We present here results on the analysis of 100 mL medium samples extracted from sterilized foam (Smithers-Oasis, Kent OH) used to support the growth of both dicotyledonous (Haplopappus gracilis, n=75) and monocotyledonous (Hemerocallis cv Autumn Blaze, n=25) aseptic plants in NASA's Plant Growth Unit (PGU) during the 5-day CHROMEX-01 Space Shuttle flight (March 1989, STS-29). At recovery, the medium remaining within each of the five floral foam blocks (for both the space flight and ground control experiments) was extracted under vacuum, filtered and subjected to elemental analyses. Concentration levels of some elements remained the same, while some decreased and others increased. A unique aspect of this experiment was that all plants were either aseptic tissue culture generated plantlets or sterile seedling clones, and the design of the PGU facilitated the maintenance of asepsis throughout the mission (confirmed by postflight microbial sampling). This permitted the elimination of microbial considerations in the interpretation of the data. The significance of these findings for growing plants in altered gravity environments are discussed

Flavonoid-rich orange juice is associated with acute improvements in cognitive function in healthy middle-aged males

Purpose: Epidemiological evidence suggests that chronic consumption of fruit-based flavonoids is associated with cognitive benefits; however, the acute effects of flavonoid-rich (FR) drinks on cognitive function in the immediate postprandial period require examination. The objective was to investigate whether consumption of FR orange juice is associated with acute cognitive benefits over 6 h in healthy middle-aged adults. Methods: Males aged 30–65 consumed a 240-ml FR orange juice (272 mg) and a calorie-matched placebo in a randomized, double-blind, counterbalanced order on 2 days separated by a 2-week washout. Cognitive function and subjective mood were assessed at baseline (prior to drink consumption) and 2 and 6 h post consumption. The cognitive battery included eight individual cognitive tests. A standardized breakfast was consumed prior to the baseline measures, and a standardized lunch was consumed 3 h post-drink consumption. Results: Change from baseline analysis revealed that performance on tests of executive function and psychomotor speed was significantly better following the FR drink compared to the placebo. The effects of objective cognitive function were supported by significant benefits for subjective alertness following the FR drink relative to the placebo. Conclusions: These data demonstrate that consumption of FR orange juice can acutely enhance objective and subjective cognition over the course of 6 h in healthy middle-aged adults

Concord grape Juice, cognitive function and driving performance: a 12 week, placebo controlled, randomised, crossover trial in mothers of pre-teen children

Background: Daily consumption of Concord grape juice (CGJ) over three to four months has been shown to improve memory function in adults with mild cognitive impairment, and reduce blood pressure in hypertensive adults. These benefits are likely due to the high concentration of polyphenols in CGJ. Increased stress can impair cognitive function and elevate blood pressure. Thus we examined the potential beneficial effect of CGJ in individuals experiencing somewhat stressful demanding lifestyles. Objective: To examine the effects of twelve weeks’ daily consumption of CGJ on cognitive function, driving performance, and blood pressure in healthy, middle-aged working mothers. Design: Twenty five healthy mothers of pre-teen children, aged 40-50 years, who were employed for > 30 hours/week consumed 12oz (355ml) CGJ (containing 777mg total polyphenols) or an energy, taste and appearance matched placebo daily for twelve weeks according to a randomised, crossover design with a four week washout. Verbal and spatial memory, executive function, attention, blood pressure and mood were assessed at baseline, six weeks and twelve weeks. Immediately following the cognitive battery, a subsample of seventeen females completed a driving performance assessment in the University of Leeds Driving Simulator. The twenty five minute driving task required participants to match the speed and direction of a lead vehicle. Results: Significant improvements in immediate spatial memory and driving performance were observed following CGJ relative to placebo. There was evidence of an enduring effect of CGJ such that participants who received CGJ in arm 1 maintained better performance in the placebo arm. Conclusions: Cognitive benefits associated with chronic consumption of flavonoid-rich grape juice are not exclusive to adults with mild cognitive impairment. Moreover, these cognitive benefits are apparent in complex everyday tasks such as driving. Effects may persist beyond cessation of flavonoid consumption and future studies should carefully consider the length of washout within crossover designs

Global dynamics of three species omnivory models with Lotka-Volterra interaction

[[abstract]]In this work, we consider the community of three species food web model with Lotka-Volterra type predator-prey interaction. In the absence of other species, each species follows the traditional logistical growth model and the top predator is an omnivore which is defined as feeding on the other two species. It can be seen as a model with one basal resource and two generalist predators, and pairwise interactions of all species are predator-prey type. It is well known that the omnivory module blends the attributes of several well-studied community modules, such as food chains (food chain models), exploitative competition (two predators-one prey models), and apparent competition (one predator-two preys models). With a mild biological restriction, we completely classify all parameters. All local dynamics and most parts of global dynamics are established corresponding to the classification. Moreover, the whole system is uniformly persistent when the unique coexistence appears. Finally, we conclude by discussing the strategy of inferior species to survive and the mechanism of uniform persistence for the three species ecosystem.[[notice]]補正完

Chronic Effects of a Wild Green Oat Extract Supplementation on Cognitive Performance in Older Adults: A Randomised, Double-Blind, Placebo-Controlled, Crossover Trial

Background and aim: Preliminary evaluation of a wild green oat extract (WGOE) (Neuravena® ELFA®955, Frutarom, Switzerland) revealed an acute cognitive benefit of supplementation. This study investigated whether regular daily WGOE supplementation would result in sustained cognitive improvements. Method: A 12-week randomised, double-blind, placebo-controlled cross-over trial of WGOE supplementation (1500 mg/day) versus placebo was undertaken in 37 healthy adults aged 67 ± 0.8 years (mean ± SEM). Cognitive assessments included the Stroop colour-word test, letter cancellation, the rule-shift task, a computerised multi-tasking test battery and the trail-making task. All assessments were conducted in Week 12 and repeated in Week 24 whilst subjects were fasted and at least 18 h after taking the last dose of supplement. Result: Chronic WGOE supplementation did not affect any measures of cognition. Conclusion: It appears that the cognitive benefit of acute WGOE supplementation does not persist with chronic treatment in older adults with normal cognition. It remains to be seen whether sustained effects of WGOE supplementation may be more evident in those with mild cognitive impairment