Microfluidic platform for liquid chromatography-tandem mass spectrometry analyses of complex peptide mixtures

A microfluidic chip that integrates all the fluidic components of a gradient liquid chromatography (LC) system is described. These chips were batch-fabricated on a silicon wafer using photolithographic processes and with Parylene as the main structural material. The fabricated chip includes three electrolysis-based electrochemical pumps, one for loading the sample and the other two for delivering the solvent gradient; platinum electrodes for delivering current to the pumps and establishing the electrospray potential; a low-volume static mixer; a column packed with silica-based reversed-phase support; integrated frits for bead capture; and an electrospray nozzle. The fabricated structures were able to withstand pressures in excess of 250 psi. The device was used to perform a liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of a mixture of peptides from the trypsin digestion of bovine serum albumen (BSA). Gradient elution through the 1.2-cm column was performed at a flow rate of 80 nL/min. Compared to the analysis of the same sample using a commercial nanoflow LC system, the chromatographic resolution was nearly as good, and the total cycle time was significantly reduced because of the minimal volume between the pumps and the column. Results demonstrate the potential of mass-produced, low-cost microfluidic systems capable of performing LC separations for proteomics applications.     

Field trial of transgenic Indian mustard plants shows enhanced phytoremediation of selenium-contaminated sediment

Three transgenic Indian mustard [Brassica juncea (L.) Czern.] lines were tested under field conditions for their ability to remove selenium (Se) from Se- and boron-contaminated saline sediment. The transgenic lines overexpressed genes encoding the enzymes adenosine triphosphate sulfurylase (APS), gamma-glutamyl-cysteine synthetase (ECS), and glutathione synthetase (GS), respectively. The APS, ECS, and GS transgenic plants accumulated 4.3, 2.8, and 2.3-fold more Se in their leaves than wild type, respectively (P < 0.05). GS plants significantly tolerated the contaminated soil better than wild type, attaining an aboveground biomass/area almost 80% of that of GS plants grown on clean soil, compared to 50% for wild type plants. This is the first report showing that plants genetically engineered for phytoremediation can perform successfully under field conditions.     

Enantiomer fractions of organic chlorinated pesticides in arctic marine ice fauna, zooplankton, and benthos

Stereoisomers of chiral chlorinated pesticides (alpha-HCH (HCH = hexachlorocyclohexane), trans- and cis-chlordane, MC5, o,p'-DDT) were quantified in arctic marine invertebrates (ice-associated amphipods Gammarus wilkitzkii, pelagic copepods Calanus hyperboreus, krill Thysanoessa inermis, and amphipods Themisto libellula, and benthic amphipods Paramphithoe hystrix). Enantiomer fractions (EFs) were calculated to investigate the influence of habitat, geographic area, and diet on selective bioaccumulation of the (-)- or (+)-enantiomer. Depletion of the (+)-alpha-HCH enantionmer increased from ice fauna to zooplankton to benthos, corresponding to previous reports of EF variations with depth. Chlordanes and o,p'-DDT also showed the strongest enantioselective bioaccumulation in benthic amphipods and less so in zooplankton and ice fauna, which had closer to racemic EFs. Neither diet nor geographic area explained EF differences among samples. Nonracemic EFs in benthos may be related to stereoselective biotransformation, but is most likely reflecting vertical distribution of EFs in the water column and sediments, as demonstrated earlier for alpha-HCH in the Canadian and European Arctic.     

Impact of nonadditive genetic effects in the estimation of breeding values for fertility and correlated traits

The effects of inbreeding, heterosis, recombination loss, and percentage Holstein on the estimation of predicted transmitting abilities for fertility traits (calving interval, number of days from calving to first insemination, nonreturn rate, number of inseminations) and correlated traits (milk yield at test nearest d 110 and body condition score) were examined in a mixed population of Holstein and Friesian cattle. An unfavorable effect of percentage Holstein on calving interval was observed, resulting in a 12-d increase for pure Holsteins compared with pure Friesians. Insemination traits were less affected by percentage Holstein, with 3% more animals returning to first service within 56 d and 0.1 more inseminations required for Holstein animals. Heterosis and recombination loss affected some of the traits. Heterosis had a favorable effect on yield, with a 0.35-kg difference between a pure and cross-bred animal for test milk. There was a reduction of 1 d to first insemination between a pure and first-crossbred animal. Inbreeding had a significant and unfavorable effect on all traits. The difference between a noninbred animal and an animal with an inbreeding coefficient of 10% was a 2.8-d increase in calving interval, a 1.7-d increase in days to first insemination, a 1% increased probability to return to estrus at first service, 0.03 more inseminations, a 0.27-unit decrease in body condition, and a 0.54-kg decrease in milk on test nearest d 110. The effect of inbreeding depression was more pronounced at higher levels of inbreeding. The rank correlations between the predicted transmitting abilities for fertility and correlated traits, with and without the additional nonadditive effects in the model, were over 0.99. Steps should be taken to control the rise in inbreeding, or the effects on fertility and correlated traits such as milk production will begin to manifest themselves.     

Blind and sighted pedestrians' judgments of gaps in traffic at roundabouts

This paper reports two experiments about street crossing under conditions of free flowing traffic, with a focus on modem roundabout intersections. Experiment 1 was conducted at three roundabouts varying in size and traffic volume. Six totally blind and six sighted adults judged whether gaps in traffic were long enough to permit crossing to the median (splitter) island before the next vehicle arrived. Gap distributions and measures of judgment quality are reported. Overall, blind participants were about 2.5 times less likely to make correct judgments than sighted participants, took longer to detect crossable gaps, and were more likely to miss crossable gaps altogether. However, the differences were significant only at the two higher volume roundabouts. In Experiment 2, we evaluated the response of drivers to pedestrians with and without mobility devices (i.e., long canes, dog guides). The experiment was conducted at a single-lane roundabout, a midblock crossing, and a two-way-stop-controlled intersection. Site-specific characteristics appeared to have a greater impact on drivers' yielding than did a mobility device. Actual or potential applications of this research include the development of methods for assessing pedestrian safety and driver behavior as well as identifying intersections that may require modification in order to be accessible to blind pedestrians.     

Inversion of Transient Electromagnetic Data from a Spherical Conductor

This paper considers the problem of inverting single loop transient electromagnetic data from a spherical conductor. First, analytical expressions are presented for the transient voltage, and then the various partial derivatives of this voltage with respect to the parameters of the ground are found. Secondly, it is shown how all these expressions can be used with existing inversion schemes, such as the Marquardt or ridge regression scheme for the inversion of data. Finally, results are presented to show that, even when the transient data is contaminated by 20-percent random noise, good estimates for the earth parameters can be found. In this case, however, only 4 parameter combinations are well resolved. Further, when there is only 5-percent noise present in the data, it is still not possible to resolve more than 5 sets of parameters.     

Further considerations for behavior-genetic analysis of humans.

Replies to R. Plomin and T. Foch's (see record 1986-00486-001) disagreement with the present authors and P. A. Rothbaum's (see record 1984-11539-001) presentation of 5 specific points in a critique of Plomin and Foch's (see record 1981-25190-001) earlier behavior-genetic analysis of personality. Rather than replying point–counterpoint to Plomin and Foch, the present authors discuss basic issues that put both critiques into a perspective useful to the application and interpretation of genetic analysis. Three relevant issues in experimental behavior-genetic studies as they apply to correlational behavior-genetic studies of human personality are described. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positive socialization via cooperative games.

Assessed the effects of a cooperatively structured games program on sharing and on happiness when playing games among 71 5-yr-olds. Ss consisted of 4 intact, half-day kindergarten classes from 2 schools. Each school had 1 experimental group and 1 control group, both of which were taught by the same classroom teacher. Experimental groups were exposed to an 18-wk cooperative games program, and control groups were exposed to a traditional games program of equal duration. Pre- and postmeasures on a candy-sharing task revealed that Ss in the cooperative games program increased their sharing significantly more than did those in the traditional games program. Overall happiness when playing games outside of school increased for all groups. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)