Probing the energy transfer dynamics of photosynthetic reaction center complexes through hole-burning and single-complex spectroscopy

Photosynthesis is the process by which light energy is used to drive reactions that generate sugars to supply energy for cellular processes. It is one of the most important fundamental biological reactions and occurs in both prokaryotic (e.g. bacteria) and eukaryotic (e.g. plants and algae) organisms. Photosynthesis is also remarkably intricate, requiring the coordination of many different steps and reactions in order to successfully transform absorbed solar energy into a biochemical usable form of energy. However, the net reaction for all photosynthetic organisms can be reduced to the following, deceptively general, equation developed by Van Niel[1] H{sub 2} - D + A {sub {implies}}{sup hv} A - H{sub 2} + D where H{sub 2}-D is the electron donor, e.g. H{sub 2}O, H{sub 2}S. A is the electron acceptor, e.g. CO{sub 2}, and A-H{sub 2} is the synthesized sugar. Amazingly, this simple net equation is responsible for creating the oxidizing atmosphere of Earth and the recycling of CO{sub 2}, both of which are necessary for the sustainment of the global ecosystem

Let\u27s All Go Up To Mauds

https://digitalcommons.library.umaine.edu/mmb-vp/1973/thumbnail.jp

Enhancement of pigmeat quality by altering pre-slaughter management

End of project reportThe studies presented in this report were conducted to investigate the effect of breed, slaughter weight, castration of male pigs and strategic feeding strategies on the performance of pigs to slaughter and on their carcass quality. The effect of breed, gender and feeding regimen on the performance of pigs and their carcass quality was examined in the first study (Section 3). From weaning to slaughter Landrace-sired pigs grew at a similar rate but had a better feed conversion efficiency compared with Duroc-sired pigs. Landrace-sired pigs also had a higher carcass lean and greater muscle depth than Duroc-sired pigs. Entire male pigs grew more efficiently, had lower lean content in their carcasses and had a reduced kill out yield when compared with gilts. The eye muscle depth was greater for gilts than entire males. Diluting the diet with grass-meal (GM) reduced growth rate, caused a deterioration in feed conversion efficiency, reduced back fat thickness, reduced eye muscle thickness and reduced kill out yield compared to the control feeding regimen of a cereal based diet. Compensatory growth was observed during a re-alimentation period following a period of diet dilution with grass-meal. However, where it did occur, in most cases it was only partial. Adding 5% rapeseed oil instead of lard to the finisher diet increased nitrogen utilization efficiency and phosphorous utilization efficiency. The effect of gender (boar, castrate, gilt) and slaughter weight (80 to 120kg) on pig performance, carcass quality, meat quality, and nitrogen excretion was investigated in the second study (Section 4). Boars grew faster than gilts and more efficiently than castrates or gilts. Castrates had a higher kill out yield than boars. Nitrogen excretion from castrates was similar to gilts which were both higher than that from boars. The processing value of carcasses from castrates may be higher than that of boars and gilts. In particular castrates had heavier loins and bellies than either boars or gilts. Carcasses from castrates and gilts had a higher temperature (recorded 24 hours post slaughter) than boars. However, pH24 was not affected by gender. The intramuscular fat content of the l. dorsi in castrates was higher than that of boars or gilts, however at 1.65% this was well below the level (2.0%) above which any noticeable sensory attributes might be detected. Feed intake increased with increasing slaughter weight and feed conversion efficiency deteriorated. N excretion also increased with each increment in weight. Carcass lean content increased up to 90kg live EOP 4939.doc 4 25/10/2005 weight then reached a plateau and declined after 110kg live weight. Heavier carcasses yielded more product for approximately the same slaughtering cost and the associated larger muscles could make it easier to use seam butchery techniques that result in lean, well-trimmed, attractive cuts and joints. The pH45 and pH24 were reduced with increasing slaughter weight and drip loss increased. Heavier pigs may be more prone to the development of PSE than lighter pigs as their carcass temperature remains higher for longer than that of lighter pigs

Consumer attitudes on salt and fat reduced foods in the Republic of Ireland

Public health campaigns are continually promoting healthier foods and in parallel many food manufacturers are working on recipes low in fat and salt. The following survey investigates how well consumers (n = 1045) in Ireland have assimilated the message of consuming healthier foods, including salt and fat reduced foods, into their diet. It seems that campaigns regarding the importance of a balanced diet have generally been adopted by respondents, as only a minority of the participants did not take care of their diet, independent of age, gender and level of education. More than half of the participants carefully maintained a balanced diet. Furthermore, an increase in purchasing salt reduced food was observed, though fat reduced food products were already better accepted. In general, men, young adults (<30 years) and lower educated people purchased less salt and fat reduced foods and took less care in maintaining a balanced diet. No conflict was observed for traditional foods reduced in salt and fat content when their intrinsic sensory character is maintained. The majority of the participants were aware of the health risks of a diet rich in salt and fat, though less participants transferred this knowledge into their diet. A very high demand for more salt and fat reduced foods on the market was observed although the smaller range of salt and fat reduced products and their higher prices might diminish the level of consumer acceptance. Launching taxation and subsidies in tandem might counteract this and furthermore, user-friendly product labelling schemes are required

Small Amounts of α-Myosin Heavy Chain Isoform Expression Significantly Increase Power Output of Rat Cardiac Myocyte Fragments

The publisher's version of this article may be found at http://circres.ahajournals.org/cgi/content/abstract/90/11/1150?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&searchid=1049671889562_931&stored_search=&FIRSTINDEX=0&volume=90&firstpage=1150&search_url=http%3A%2F%2Fcircres.ahajournals.org%2Fcgi%2Fsearch&journalMyocardial performance is likely affected by the relative expression of the two myosin heavy chain (MyHC) isoforms, namely {alpha}-MyHC and ß-MyHC. The relative expression of each isoform is regulated developmentally and in pathophysiological states. Many pathophysiological states are associated with small shifts in the relative expression of each MyHC isoform, yet the functional consequence of these shifts remains unclear. The purpose of this study was to determine the functional effect of a small shift in the relative expression of {alpha}-MyHC. To this end, power output was measured in rat cardiac myocyte fragments that expressed {approx}12% {alpha}-MyHC and in myocyte fragments that expressed {approx}0% {alpha}-MyHC, as determined in the same cells by SDS-PAGE analysis after mechanical experiments. Myocyte fragments expressing {approx}12% {alpha}-MyHC developed {approx}52% greater peak normalized power output than myocyte fragments expressing {approx}0% {alpha}-MyHC. These results indicate that small amounts of {alpha}-MyHC expression significantly augment myocyte power output.This work was supported by National Heart, Lung, and Blood Institute Grant HL-57852 (K.S.M.) and a predoctoral fellowship granted by the Heartland Affiliate of the American Heart Association (T.J.H.)

Rapid descriptive consumer analysis using simultaneous and monadic sample presentation for coffee

The objective of this study was to investigate how rapid descriptive consumer analysis using simultaneous presentation of samples compared with monadic presentation of samples, using both affective and descriptive sensory evaluation methods. Simultaneous presentation of coffee samples for sensory acceptance testing, using ranking analysis, was conducted using naïve assessors. In a separate session, assessors evaluated the same coffee samples, using monadic presentation and employing the same scales. Similarly, descriptive consumer analysis, using simultaneous and monadic sample presentation, was conducted using descriptive attributes chosen by the panel. For RDA (Ranking descriptive analysis), coffee samples were presented simultaneously (randomised) to assessors and subsequently ranked. The process was then repeated using the same assessors; however, samples were presented in monadic and randomised presentation order. Data accumulated from the study were analysed by Analysis of Variance (APLSR-ANOVA Partial Least Squares Regression). Results obtained indicate that simultaneous presentation of samples was more effective than monadic presentation, as a larger amount of attributes with significant (P < 0.05) intensity differences were observed using RDA. Thus, simultaneous presentation of samples also allows ranking in SAT evaluation and proved a useful tool in establishing the hedonic attributes of products. We propose to call this method Ranking Acceptance Analysis (RAA)

Investigating the influence of ultrasound pre-treatment on drying kinetics and moisture migration measurement in Lactobacillus sakei cultured and uncultured beef jerky

Low Frequency-Nuclear Magnetic Resonance (LF-NMR) was employed to elucidate changes in water distribution in cultured (Lactobacillus sakei) and uncultured beef jerky samples subjected to ultrasound pre-treatment. Ultrasound pre-treatment at frequencies of 25, 33 and 45 kHz for 30 min, followed by marination (18 h) was carried out for both cultured and uncultured jerky samples. Among the various kinetic models assessed, the Wang and Singh model provided the closest fit to the drying experimental data, with high R2 (≥0.994), low RMSE (≤0.023) and low AICc (100 ms (T22), respectively. Results presented in this study demonstrates that the ultrasound effect on drying behaviour was frequency dependent and that LF-NMR can be employed to evaluate moisture mobility and drying degree of beef jerky

Sensory optimisation of salt-reduced corned beef for different consumer segments

peer-reviewedThe study objectives were to determine assessors' (n = 256) preference for corned beef, produced with sequential reductions in NaCl concentrations and to determine if preference was affected by assessor age. The use of a salt replacer such as potassium lactate was also assessed. The youngest age cohort disliked samples containing the highest level of NaCl, whereas the oldest age cohort did not detect differences between samples. The most negatively perceived sample was the control, suggesting that NaCl levels added to commercial corned beef are currently too high for consumer acceptance. All age cohorts, with the exception of the 65–74 age cohort, accepted corned beef samples possessing NaCl levels closest to the FSAI target (1.63 g/100 g). No major sensory differences were noted between samples with and without potassium lactate by the ≥65 age cohort. Potassium lactate may be added to corned beef without affecting sensory attributes, whilst enhancing nutritional content. Assessors of varying age groups have differing preferences for certain NaCl levels and salt replacers