Strengths and Weaknesses of Recently Engineered Red Fluorescent Proteins Evaluated in Live Cells Using Fluorescence Correlation Spectroscopy

The scientific community is still looking for a bright, stable red fluorescent protein (FP) as functional as the current best derivatives of green fluorescent protein (GFP). The red FPs exploit the reduced background of cells imaged in the red region of the visible spectrum, but photophysical short comings have limited their use for some spectroscopic approaches. Introduced nearly a decade ago, mCherry remains the most often used red FP for fluorescence correlation spectroscopy (FCS) and other single molecule techniques, despite the advent of many newer red FPs. All red FPs suffer from complex photophysics involving reversible conversions to a dark state (flickering), a property that results in fairly low red FP quantum yields and potential interference with spectroscopic analyses including FCS. The current report describes assays developed to determine the best working conditions for, and to uncover the shortcoming of, four recently engineered red FPs for use in FCS and other diffusion and spectroscopic studies. All five red FPs assayed had potential shortcomings leading to the conclusion that the current best red FP for FCS is still mCherry. The assays developed here aim to enable the rapid evaluation of new red FPs and their smooth adaptation to live cell spectroscopic microscopy and nanoscopy.     

Motivational counseling reduces future police charges in court referred youth

By the age of 18, between 16 and 27% of adolescents in the U.S. have been arrested for an offense and by the age of 23 this increases to a staggering 25–41%. Most youth that get into legal trouble have a substance abuse problem and many youth report high risk driving behaviors. Adjudication of adolescents for an offense may provide an opportunity to provide a secondary prevention program for such high risk behaviors. In this regard the primary aim of the present study was to test two hypotheses: (1) that interventions involving group motivational interviewing would decrease future legal charges beyond those achieved by the combination of sanctions and remedial actions otherwise mandated by the court; and (2) that the addition of a trauma room exposure to the group MI intervention would increase the effectiveness of MI in decreasing these future legal charges.     

Effects of block length and solution-casting conditions on the final morphology and properties of disulfonated poly(arylene ether sulfone) multiblock copolymer films for proton exchange membranes

The effects of block length and solution-casting conditions on the final microstructures and properties of disulfonated poly(arylene ether sulfone) multiblock copolymer (BPSH100-BPS0) films for proton exchange membranes were investigated based on the basic principles of microstructure formation of block copolymers. Morphological studies using transmission electron microscopy and small angle X-ray scattering demonstrated that as the block length increased, the inter-ionic-domain distance increased, with a subsequent increase in lamellar ordering and long-range continuity. Further enhancement in morphological order was achieved by simply utilizing a selective solvent, dimethylacetamide, which is good and marginal for the sulfonated and unsulfonated blocks, respectively, rather than a neutral solvent, N-metyl-2-pyrrolidone. These morphological enhancements led to higher proton conductivity and water uptake. Drying temperature and/or solvent removal rate were observed to have considerable effects on water uptake and swelling behavior, being coupled with solvent selectivity. Also, the multiblock copolymer consisting of longer blocks was found to be more sensitive to the variation of the processing conditions such as solvent type and film drying temperature.     

Elytra boost lift,but reduce aerodynamic efficiency in flying beetles

Flying insects typically possess two pairs of wings. In beetles, the front pair has evolved into short, hardened structures, the elytra, which protect the second pair of wings and the abdomen. This allows beetles to exploit habitats that would otherwise cause damage to the wings and body. Many beetles fly with the elytra extended, suggesting that they influence aerodynamic performance, but little is known about their role in flight. Using quantitative measurements of the beetle''s wake, we show that the presence of the elytra increases vertical force production by approximately 40 per cent, indicating that they contribute to weight support. The wing-elytra combination creates a complex wake compared with previously studied animal wakes. At mid-downstroke, multiple vortices are visible behind each wing. These include a wingtip and an elytron vortex with the same sense of rotation, a body vortex and an additional vortex of the opposite sense of rotation. This latter vortex reflects a negative interaction between the wing and the elytron, resulting in a single wing span efficiency of approximately 0.77 at mid downstroke. This is lower than that found in birds and bats, suggesting that the extra weight support of the elytra comes at the price of reduced efficiency.     

Retail cutting characteristics for US Choice and US Select beef subprimals

US Choice (Ch) and US Select (Se) beef subprimals from the rib, chuck, plate, loin, and round were obtained to conduct retail cutting tests. Subprimals were merchandised into bone-in or boneless retail cuts and associated components by experienced retail meat merchandisers. These Se subprimals had less (P<0.05) trimmable fat than their Ch counterparts: ball tip, top sirloin, outside round, inside round, and ribeye. Se inside rounds, outside rounds, eye of rounds, boneless striploins, and ball tips had greater (P<0.05) purge losses than the same cuts from Ch. The only subprimals where grade impacted total saleable yield were the top (inside) rounds (Ch=80.13%, Se=87.34%; P=0.004) and outside rounds cut into roasts, steaks, and cubed steaks (Ch=87.61%, Se=90.28%; P=0.05). Methods to increase retail yields from beef subprimals should consider minimizing purge and increasing cutting efficiencies in addition to reducing fat trim.     

Factors influencing the variation in tenderness of seven major beef muscles from three Angus and Brahman breed crosses

Beef carcasses (n=30) from 3/4 Angus (A)×1/4 Brahman (B), 1/4A×3/4B, and 1/2A×1/2B F(1) crosses were used to evaluate breed type, electrical stimulation, and postmortem aging on the M. semimembranosus (SM), M. semitendinosus (ST), M. biceps femoris (BF), M. vastus lateralis (VL), M. gluteus medius (GM), M. longissimus dorsi lumborum (LD), and M. triceps brachii (TB). Shear force values decreased with increased postmortem aging to a greater extent in steaks from 3/4A×1/4B than steaks from the other breed types. Shear force values for steaks from the round (SM, ST, BF, VL) were higher than steaks from the loin (LD, GM) and chuck (TB) for both electrically stimulated and non-electrically stimulated muscles. In the LD muscle, calpastatin activities were similar among breed types. Muscle type played the greatest role in determining tenderness.     

In-home consumer evaluations of individual muscles from beef rounds subjected to tenderization treatments

In-home evaluations of the M. vastus lateralis, M. rectus femoris, M. semimembranosus, and M. adductor (n=266) muscles that were either blade tenderized, enhanced with a salt and phosphate solution, or served as a control (no tenderization or enhancement treatment) were conducted. Consumers (n=261) cooked these steaks and were asked to document cooking method and degree of doneness, and provide palatability ratings for each steak. Enhancing round muscles with a salt and phosphate solution improved most palatability traits compared to blade tenderized or control steaks. For M. semimembranosus and M. vastus lateralis, the enhanced steaks received higher (P<0.05) ratings for all palatability traits. Cooking method and degree of doneness had little influence on consumer palatability ratings, and where differences occurred, they were muscle specific. This may allow limited recommendations for the most appropriate cooking method and degree of doneness for specific beef round muscles.     

Case Study: Modeling the Lateral Mobility of the Rio Grande below Cochiti Dam, New Mexico

The Cochiti reach of the Rio Grande served as a case study to test the hypothesis that the lateral mobility of an alluvial river decreases as the river approaches equilibrium. The lateral mobility of the river was measured using a geographic information system from digitized aerial photographs of the nonvegetated active channel between 1918 and 2001. Reach-averaged lateral mobility was quantified in terms of width change, lateral migration, and total lateral movement. By 2001, the width of the Cochiti Reach was close to the expected equilibrium width indicating that the river had adjusted to the incoming water and sediment load. An exponential equation based on deviation from equilibrium width described 95–96% of the variance in channel width, 78–90% of variance in migration rates, and 92% of the variance in total lateral movement between 1918 and 1992. For validation of the model, the 2001 width and migration rates were predicted with errors as low as 19 and 8%, respectively. The exponential width model was also applied to four other rivers that exhibited narrowing trends following dam construction and explained 82–89% of the variance in width change on those rivers.     

Droplet charge-to-mass ratio measurement in an EHD liquid-liquidextraction system

The application of a high voltage electric field to enhance the rate of mass transfer in liquid-liquid extraction has been an active subject of investigation in recent years. The electrohydrodynamic (EHD) forces generated by electric fields at a liquid-liquid interface have a potential application in chemical processing industry solvent extraction processes. In this work, the charge-to-mass ratio of droplets formed in an EHD liquid-liquid extraction system has been investigated experimentally and theoretically. The results reported from the present investigation, extending from the single discrete droplet regime (at low applied voltages) to the dispersed multi-droplet regime (at high applied voltages), indicate that the modified Rayleigh instability model and Vonnegut and Neubauer model can explain maximum droplet charge acquired in liquid-liquid systems, especially the modified Vonnegut and Neubauer model which can predict most of the experimental results when the applied electric field is high enough and EHD forces become dominant     

Determining genetic variability in the distribution of sensitivities to toxic stress among and within field populations of Daphnia magna

To extrapolate credibly from individuals in the laboratory to field populations, it is essential to account for genetic differences in susceptibility to toxic stress and thus incorporate genetic variability into ecological risk estimates. In this study, the distribution of sensitivities across two toxic chemicals among and within field populations of Daphnia magna were used to quantify genetic variability. The study employed 30 D. magna clones from three geographically separate European populations. The sensitivity of each population studied and its constituent clones was estimated in terms of the concentrations of lambda-cyhalothrin and cadmium impairing individual fitness by 10 and 50% (EC10-50). Results revealed that differences in tolerance among clones within populations were large when compared with differences between populations and that the genetic range of sensitivities to toxic stress within populations was log-normally distributed. Furthermore, reported variation in sensitivity values to toxic stress among different laboratory species, populations, and clones was similar to that observed among and within field populations of Daphnia. These results suggest that it is possible to estimate genetic variability by estimating the tolerance distribution of laboratory populations and clones and that extrapolation approaches currently used in ecological risk assessment should explicitly incorporate genetic variability in tolerance into risk estimates.