In Google We Trust: Users' Decisions on Rank, Position, and Relevance

An eye tracking experiment revealed that college student users have substantial trust in Google's ability to rank results by their true relevance to the query. When the participants selected a link to follow from Google's result pages, their decisions were strongly biased towards links higher in position even if the abstracts themselves were less relevant. While the participants reacted to artificially reduced retrieval quality by greater scrutiny, they failed to achieve the same success rate. This demonstrated trust in Google has implications for the search engine's tremendous potential influence on culture, society, and user traffic on the Web.     

Biochemical properties and cellular localization of the Drosophila DG1 cGMP-dependent protein kinase

The protein encoded by the Drosophila cGMP-dependent protein kinase gene, DG1, was expressed in Sf9 cells. cGMP (10 microM) stimulated histone H2B phosphorylation by the DG1 protein kinase 20-fold. Maximal activity was observed at 40-50 mM Mg2+. The concentrations of cGMP, cAMP, cIMP, 8-bromo-cGMP, and 8-bromo-cAMP that gave 50% activation were 0.19 +/- 0.06, 11.7 +/- 2.8, 5.3 +/- 1.5, 0.04 +/- 0. 01, and 0.62 +/- 0.06 microM, respectively. cGMP activation was cooperative with a Hill coefficient (nH) of 1.28 +/- 0.10, whereas activation by cAMP was not cooperative. DG1 kinase expressed in Sf9 cells was found to be a dimer with an amino-terminal dimerization domain. It also autophosphorylated in a reaction stimulated by cGMP and cAMP. Immunoadsorbed DG1 protein from fly extracts was also capable of autophosphorylation, and this assay was used to quantitate the DG1 kinase in extracts from heads and bodies of adults and whole embryos. Activity was highest in heads of either sex and male bodies, intermediate in female bodies, and lowest in embryos. These results were in accord with DG1 mRNA abundance. Tissue distribution of the DG1 kinase was investigated by immunohistochemistry. In embryos, specific immunoreactivity was observed in large cells scattered along the anterior-posterior axis at stage 13. Prominent staining of adult heads was restricted to the proximal level of the lamina cortex.     

Neutron and X-ray reflectivity studies of human serum albumin adsorption onto functionalized surfaces of self-assembled monolayers

Endurance exercise training increases fat oxidation during large muscle mass exercise. Although the source of this fat has been thought to be plasma free fatty acids (FFA) released from adipose tissue, the training-induced decrease in lipolytic hormonal responses to exercise is not consistent with this concept. The purpose of this communication is to review findings, from our laboratory indicating that, in young healthy subjects, endurance exercise training reduces plasma FFA turnover and oxidation during moderate intensity prolonged 2-leg cycling while simultaneously enhancing depletion of triglycerides from the active musculature. Evidence is presented that metabolism of intramuscular triglycerides can explain the increase in total fat oxidation observed in the trained state during large muscle mass exercise. However, these results may not be applicable to exercise involving small muscle groups, a distinction that is likely to be important in explaining the apparent conflict between our findings and those from other laboratories where experimental conditions were different. In summary, for large muscle mass exercise up to 2 h in duration, plasma FFA are a less important fuel source in the trained state, and intramuscular triglycerides supply the major portion of the increase in oxidized fatty acids.     

Collection of peripheral blood progenitor cells after the administration of cyclophosphamide, etoposide, and granulocyte-colony-stimulating factor: an analysis of 497 patients

BACKGROUND: There is great interpatient variability in the number of peripheral blood stem cells collected, as measured by CD34+ cell content, after the administration of chemotherapy and a growth factor. The ability to predict patients who fail to yield adequate quantities of CD34+ cells would be of value. However, very few reports include large numbers of patients treated in an identical fashion. STUDY DESIGN AND METHODS: Between 1991 and 1995, 497 consecutive patients with a variety of malignant diseases received cyclophosphamide (4 g/m2), etoposide (600 mg/m2), and granulocyte-colony-stimulating factor (6 micrograms/kg/day) for mobilization and collection of a target dose > or = 2.5 x 10(8) CD34+ cells per kg. Multivariate analyses were performed to determine the factors associated with failure to achieve this target harvest. RESULTS: A median of 14.71 x 10(6) CD34+ cells per kg (range, 0.08-137.55) was harvested with a median of 2 (range, 1-11) apheresis procedures. Ninety-one percent of patients yielded > or = 2.5 x 10(5) CD34+ cells per kg. Patients with Stage II-III breast cancer, who had pretreatment platelet counts > or = 150 x 10(9) per L and patients who underwent < or = 1 prior chemotherapy regimen had improved CD34+ cell yields. However, most patients with adverse risk factors yielded > or = 2.5 x 10(6) CD34+ cells per kg. CONCLUSION: A regimen of cyclophosphamide, etoposide, and granulocyte-colony-stimulating factor led to the successful collection of adequate numbers of CD34+ cells in most patients without excessive toxicity. These observations confirm previous reports that intense prior therapy adversely affects the quantity of CD34+ cells harvested. Pretreatment and posttreatment variables did not predict with any certainty the small fraction of patients who fail to yield > or = 2.5 x 10(6) CD34+ cells per kg via multiple apheresis procedures.     

The soluble alpha-mannosidases of Drosophila melanogaster

The alpha-mannosidases are implicated in both the catabolism of carbohydrates and the N-linked glycosylation pathway in insects, but little is known of the biochemistry of these glycosidases. In order to study the soluble alpha-mannosidases of Drosophila melanogaster we have used artificial fluorogenic substrates for detection of activity in situ following non-denaturing gel electrophoresis. This approach also permitted examination of the mannosidases present in different tissues and the sensitivity of the enzymes to known mannosidase inhibitors. Fluorogenic substrates were also used to determine the pH optima of partly purified mannosidases. We report that D. melanogaster contains several soluble alpha-mannosidase activities. Acidic mannosidases were detected in the gut, fat body and haemolymph of third-instar larvae. The major activity detected in larval guts was a neutral mannosidase presumed to be involved in digestion.     

Visual gap and offset discrimination and its relation to categorical identification in brief line-element displays.

Visual processing was investigated in judgments of relative line position. Stimulus continua were generated by bisecting a straight line and displacing the segments. Experiment 1 measured discrimination of pairs of longitudinally displaced segments at equal steps along the continuum. At long (2 s) durations discrimination fell smoothly, but at short (100 ms) durations it was sharp-peaked. In Experiment 2 the short-duration stimuli were labeled with subsets of the labels no gap, just a gap, and more than just a gap. Theoretical discrimination performances were computed and the one based on no gap and just a gap closely fitted observed performance. Experiments 3 and 4 were similar to 1 and 2, with lateral replacing longitudinal displacement. Similar "categorical" performance was obtained. It was concluded that there are discrete mechanisms for early detection of relative line position and that 2 labels can be used to characterize performance in each direction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A model agreement for genetic research in socially identifiable populations

Genetic research increasingly focuses on population-specific human genetic diversity. However, the naming of a human population in public databases and scientific publications entails collective risks for its members. Those collective risks can be evaluated and protections can be put in place by the establishment of a dialogue with the subject population, before a research study is initiated. Here we describe an agreement to undertake genetic research with a Native American tribe. We identified the culturally appropriate public and private social units within which community members are accustomed to make decisions about health. We then engaged those units in a process of communal discourse. In their discourses about our proposed study, community members expressed most concern about culturally specific implications. We also found that, in this population, private social units were more influential in communal decision making than were public authorities. An agreement was reached that defined the scope of research, provided options for naming the population in publications (including anonymity), and addressed the distribution of royalties from intellectual property, the future use of archival samples, and specific cultural concerns. We found that informed consent by individuals could not fully address these collective issues. This approach may serve as a general model for the undertaking of population-specific genetic studies.     

Isolation of translactone-containing triterpenes with thrombin inhibitory activities from the leaves of Lantana camara

Methanolic extracts prepared from the leaves of Lantana camara have been found to inhibit human thrombin. An assay, in which thrombin activity is measured as a function of clot formation from fibrinogen, was used to guide the fractionation and purification of five principal active constituents (1-5), which were all characterized as 5,5-trans-fused cyclic lactone-containing euphane triterpenes.     

Fabrication and characterization of transducer elements in two-dimensional arrays for medical ultrasound imaging

Some of the problems of developing a two-dimensional (2-D) transducer array for medical imaging are examined. The fabrication of a 2-D array material consisting of lead zirconate titanate (PZT) elements separated by epoxy is discussed. Ultrasound pulses and transmitted radiation patterns from individual elements in the arrays are measured. A diffraction theory for the continuous wave pressure field of a 2-D array element is generalized to include both electrical and acoustical cross-coupling between elements. This theory can be fit to model the measured radiation patterns of 2-D array elements, giving an indication of the level of cross-coupling in the array, and the velocity of the acoustic cross-coupling wave. Improvements in bandwidth and cross-coupling resulting from the inclusion of a front acoustic matching layer are demonstrated, and the effects of including a lossy backing material on the array are discussed. A broadband electrical matching network is described, and pulse-echo waveforms and insertion loss from a 2-D array element are measured.