Analysis of Liquid-Phase Chemical Detection Using Guided Shear Horizontal-Surface Acoustic Wave Sensors

Direct chemical sensing in liquid environments using polymer-guided shear horizontal surface acoustic wave sensor platforms on 36° rotated Y-cut LiTaO3 is investigated. Design considerations for optimizing these devices for liquid-phase detection are systematically explored. Two different sensor geometries are experimentally and theoretically analyzed. Dual delay line devices are used with a reference line coated with poly (methyl methacrylate) (PMMA) and a sensing line coated with a chemically sensitive polymer, which acts as both a guiding layer and a sensing layer or with a PMMA waveguide and a chemically sensitive polymer. Results show the three-layer model provides higher sensitivity than the four-layer model. Contributions from mass loading and coating viscoelasticity changes to the sensor response are evaluated, taking into account the added mass, swelling, and plasticization. Chemically sensitive polymers are investigated in the detection of low concentrations (1-60 ppm) of toluene, ethylbenzene, and xylenes in water. A low-ppb level detection limit is estimated from the present experimental measurements. Sensor properties are investigated by varying the sensor geometries, coating thickness combinations, coating properties, and curing temperature for operation in liquid environments. Partition coefficients for polymer-aqueous analyte pairs are used to explain the observed trend in sensitivity for the polymers PMMA, poly(isobutylene), poly(epichlorohydrin), and poly(ethyl acrylate) used in this work

ATR-FTIR Spectroscopic Analysis of Sorption of Aqueous Analytes into Polymer Coatings Used with Guided SH-SAW Sensors

Attenuated total internal reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used for the investigation of sorption of aqueous solutions of analytes into polymer coatings. A series of simple model polymers, such as poly(dimethylsiloxane), poly(epichlorhydrin), and poly(isobutylene), and films and analytes, such as aqueous solutions of ethylbenzene, xylenes, toluene, and nitrobenzene, were used to evaluate the use of ATR-FTIR spectroscopy as a screening tool for sensor development. The ratios of integrated infrared absorption bands provided a simple and efficient method for predicting trends in partition coefficients. Responses of polymer-coated guided shear horizontal surface acoustic wave (SH-SAW) sensor platforms to the series of analytes, using polymer coatings with similar viscoelastic properties, were consistent with ATR-FTIR predictions. Guided SH-SAW sensor responses were linear in all cases with respect to analyte concentration in the tested range. Comparison of ATR-FTIR data with guided SH-SAW sensor data identifies cases where mass loading is not the dominant contribution to the response of the acoustic wave sensor. ATR-FTIR spectra of nitrobenzene, coupled with computational chemistry, provided additional insight into analyte/polymer interactions

Assessment of Leading Health Educators in Select General Readership Magazines, 2005-2008

Mass media can play an important role in setting public agenda and stimulating public attention to issues. Purpose: To assess health-related articles in select mass-circulating general readership magazines, and identify which of the Leading Health Indicators (LHI) each of them addresses. Methods: Four of the top 35 general readership magazines listed in the 2007 Magazine Publishers of America were considered, and included Reader’s Digest, Time, Newsweek, and U.S. News and World Report. ProQuest was searched to obtain all health-related articles (n=55) available in these magazines between July 2005 and August 2008. Articles were assessed in regards to LHIs, sources of information, presentation of statistics and risk factors, and citation of prevention measures. Results: The most frequent LHIs addressed were overweight and obesity (21.4%) and mental health (19%). The most frequent source of information was experts such as MDs and PhDs (92.9%). Incidence and prevalence of LHIs were frequently presented, while risk factors were presented in less than 25% of the articles. Conclusion: Mass media can be a valuable tool for dissemination and stimulation of public attention to high priority public health issues. Enhanced coordination is needed between health educators and members of the press to ensure accurate and universally relevant health information in general readership magazines

RNA interference gene therapy in dominant retinitis pigmentosa and cone-rod dystrophy mouse models caused by GCAP1 mutations

pre-printRNA interference (RNAi) knockdown is an efficacious therapeutic strategy for silencing genes causative for dominant retinal dystrophies. To test this, we used self-complementry (sc) AAV2/8 vector to develop an RNAi-based therapy in two dominant retinal degeneration mouse models. The allele-specific model expresses transgenic bovine GCAP1(Y99C) establishing a rapid RP-like phenotype, whereas the nonallele-specific model expressed mouse GCAP1(L151F) producing a slowly progressing cone-rod dystrophy (CORD). The late onset GCAP1(151F)-CORD mimics the dystrophy observed in human GCAP1-CORD patients. Subretinal injection of scAAV2/8 carrying shRNA expression cassettes specific for bovine or mouse guanylate cyclase-activating protein 1 (GCAP1) showed strong expression at 1 week post-injection. In both allele-specific [GCAP1(Y99C)-RP] and nonallele-specific [GCAP1(L151F)-CORD] models of dominant retinal dystrophy, RNAi-mediated gene silencing enhanced photoreceptor survival, delayed onset of degeneration and improved visual function. Such results provide a "proof of concept" toward effective RNAi-based gene therapy mediated by scAAV2/8 for dominant retinal disease based on GCAPi mutation. Further, nonallele-specific RNAi knockdown of GCApi may prove generally applicable toward the rescue of any human GCApi-based dominant cone-rod dystrophy

Separation Of Soil Evaporation And Vegetation Transpiration By MODIS Data For Central And Northern China

Evapotranspiration(ET) plays a crucial role in the hydrologic system. To estimate evapotranspiration quantitatively in a large scale, remote sensing data has been used in a number of models and shows its applicability in the estimation of evapotranspiration. In this paper, evapotranspiration for central and northern China was derived from MODIS data. In arid and semi-arid regions, soil evaporation can be considered as the minimum water requirement for bare area, while evapotranspiration can be considered as the minimum water demand for the area covered by vegetation. Hence the separation of soil evaporation and vegetation transpiration is valuable for efficient water resources management. In this study, the land surface temperature-fractional vegetation coverage(Ts-f) trapezoid method was applied in conjunction with an operational two-layer model. A modified algorithm for the determination of actual dry/wet edges(MADE) of the Ts-f trapezoid was proposed, which is an improvement of the original method based on Ts-VI(vegetation index) triangle developed by Ronglin Tang(2010). The MADE algorithm was then integrated with the two-layer model to estimate the latent heat flux (evaporation and transpiration). It’s showed that the retrieved latent heat flux is in good agreement with FLUXNET data obtained from Department of Biogeochemical Integration. The root mean square error of monthly ET is below 25 W/m2. The result demonstrated that the accuracy of the modified algorithm to determine dry/wet edges in the Ts-f trapezoid was satisfactory. Finally, the spatial and temporal distribution of soil evaporation and vegetation transpiration of central and northern China was further investigated in this study

Inactivity of human β,β-carotene-9′, 10-′dioxygenase (BCO2) underlies retinal accumulation of the human macular carotenoid pigment

pre-printThe macula of the primate retina uniquely concentrates high amounts of the xanthophyll carotenoids lutein, zeaxanthin, and meso-zeaxanthin, but the underlying biochemical mechanisms for this spatial- and species-specific localization have not been fully elucidated. For example, despite abundant retinal levels in mice and primates of a binding protein for zeaxanthin and mesozeaxanthin, the pi-isoform of glutathione S-transferase (GSTP1), only human and monkey retinas naturally contain detectable levels of these carotenoids. We therefore investigated whether or not differences in expression, localization, and activity between mouse and primate carotenoid metabolic enzymes could account for this species-specific difference in retinal accumulation. We focused on β,β-carotene-9',10'-dioxygenase (BCO2; also known as BCDO2), the only known mammalian xanthophyll cleavage enzyme. RT-PCR, western blot analysis, and immunohistochemistry confirmed that BCO2 is expressed in both mouse and primate retinas. Cotransfection of expression plasmids of human or mouse BCO2 into E. coli strains engineered to produce zeaxanthin demonstrated that only mouse BCO2 is an active zeaxanthin cleavage enzyme. Surface plasmon resonance (SPR) binding studies showed that the binding affinities between human BCO2 and lutein, zeaxanthin, and meso-zeaxanthin are 10- to 40-fold weaker than those for mouse BCO2, implying that ineffective capture of carotenoids by human BCO2 prevents cleavage of xanthophyll carotenoids. Moreover, BCO2 knockout mice, unlike wild-type mice, accumulate zeaxanthin in their retinas. Our results provide a novel explanation for how primates uniquely concentrate xanthophyll carotenoids at high levels in retinal tissue

Recording brain activity can function as an implied social presence and alter neural connectivity.

People often behave differently when they know they are being watched. Here, we report the first investigation of whether such social presence effects also include brain monitoring technology, and also their impacts on the measured neural activity. We demonstrate that merely informing participants that fMRI has the potential to observe (thought-related) brain activity is sufficient to trigger changes in functional connectivity within and between relevant brain networks that have been previously associated selectively with executive and attentional control as well as self-relevant processing, social cognition, and theory of mind. These results demonstrate that an implied social presence, mediated here by recording brain activity with fMRI, can alter brain functional connectivity. These data provide a new manipulation of social attention, as well as shining light on a methodological hazard for researchers using equipment to monitor brain activity

Part-time Employment in the United States

[Excerpt] To say that part-time workers are less costly than full-time workers, however, is not an explanation for the trend in the use of part-time employees that has occurred. Rather, one must show that the relative cost advantage of part-time workers has increased over time and that variations in the relative cost advantage are associated with variations in the usage of part-time employment. Somewhat surprisingly, few researchers have tried to do this, and even these only indirectly. This paper addresses this issue, albeit in a slightly different way, focusing on data from the United States. We begin in the next section by analyzing data on part-time employment in the United States. After controlling for cyclical factors, an increasing trend in the usage of part-time employment is observed. Moreover, it is clear from the component of part-time employment that is increasing that this is a demand-side, not a supply-side phenomenon

Getting E-Books into Courses: How Libraries Can Partner with Faculty to Ease the Textbook Affordability Crisis

Academic libraries have implemented various initiatives to help reduce the cost students pay for learning materials. Popular initiatives including promoting open educational resources (OER), inclusive access programs, and curriculum-based collection development. A recent survey conducted by Library Journal/EBSCO identified several barriers to faculty engagement with e-books in courses. This paper will discuss those barriers, as well as the efforts at two Louisiana universities, under the leadership of the statewide academic library consortium (LOUIS), to promote both OER and library-purchased e-books, and address challenges to faculty and student engagement with these materials. In addition to these, some libraries have implemented programs to purchase books assigned to courses as e-books and made them available to students free of charge. One such program has been in place at Louisiana State University (LSU) since 2014. This paper will describe that program, including its efforts to engage faculty members, as well as similar efforts at the University of New Orleans (UNO). Among the efforts to engage faculty is LSU’s “e-Textbooks for Faculty” portal; a website that enables faculty members to search for relevant e-books. A similar tool, created by EBSCO to serve a state consortium, will also be discussed. Finally, user testing was conducted to understand whether an existing library e-textbook product (EBSCO) sufficiently supported the course-reading workflow; this paper will discuss that testing as well as recommendations for platforms seeking to support this use case

A model for transport of membrane-associated phototransduction polypeptides in rod and cone photoreceptor inner segments

AbstractWe discuss putative mechanisms of membrane protein transport in photoreceptors based on Pde6d and Gucy2e/Gucy2f knockout mice. Knockout of the Pde6d gene encoding PrBP/δ, a prenyl binding protein present in the retina at relatively high levels, was shown to impair transport of G-protein coupled receptor kinase 1 (GRK1) and cone phosphodiesterase α′ subunit (PDE6α′) to the rod and cone outer segments. Other prenylated proteins are minimally affected, suggesting some specificity of interaction. Knockout of the Gucy2e gene encoding guanylate cyclase 1 (GC1) disrupted transport of G-protein coupled receptor kinase 1 (GRK1), cone PDE6α′, cone transducin α and γ subunits (cTα and cTγ) to the cone outer segments, while a GC1/GC2 double knockout prevented transport of rod PDE6, but not transducin, GRK1, or rhodopsin, to the rod outer segments. These knockout phenotypes suggest that PrBP/δ functions in extracting prenylated proteins from the endoplasmic reticulum (ER) where they dock after prenylation, and that GC-bearing membranes may co-transport peripheral membrane proteins in vesicles. We conclude that distinct pathways have evolved in rods and cones for transport of integral and peripherally membrane-associated proteins