Broadening Our View About Technology Integration: Three Literacy Educators\u27 Perspectives

What can we realistically expect teacher educators to do with technology, given the contexts in which they find themselves, the skills that they bring to their contexts, and the changes that they would need to make? We attempt to answer this question through three self-studies as we integrated technology into methods courses and student teaching supervision. Data sources included reflective journals, lesson plans, observations, and interviews. Pre-established categories and constant comparative method were used to analyze the data. Three common themes emerged (the issue of technology integration; the interdependence of skills, responsibilities, and context; and the mediation of context) that lead us to conclude that the notion of technology integration varies in different contexts

Development of the WRF-CO2 4D-Var assimilation system v1.0

Regional atmospheric CO2 inversions commonly use Lagrangian particle trajectory model simulations to calculate the required influence function, which quantifies the sensitivity of a receptor to flux sources. In this paper, an adjoint-based four-dimensional variational (4D-Var) assimilation system, WRF-CO2 4D-Var, is developed to provide an alternative approach. This system is developed based on the Weather Research and Forecasting (WRF) modeling system, including the system coupled to chemistry (WRF-Chem), with tangent linear and adjoint codes (WRFPLUS), and with data assimilation (WRFDA), all in version 3.6. In WRF-CO2 4D-Var, CO2 is modeled as a tracer and its feedback to meteorology is ignored. This configuration allows most WRF physical parameterizations to be used in the assimilation system without incurring a large amount of code development. WRF-CO2 4D-Var solves for the optimized CO2 flux scaling factors in a Bayesian framework. Two variational optimization schemes are implemented for the system: the first uses the limited memory Broyden-Fletcher-Goldfarb-Shanno (BFGS) minimization algorithm (L-BFGS-B) and the second uses the Lanczos conjugate gradient (CG) in an incremental approach. WRFPLUS forward, tangent linear, and adjoint models are modified to include the physical and dynamical processes involved in the atmospheric transport of CO2. The system is tested by simulations over a domain covering the continental United States at 48 km × 48 km grid spacing. The accuracy of the tangent linear and adjoint models is assessed by comparing against finite difference sensitivity. The system\u27s effectiveness for CO2 inverse modeling is tested using pseudo-observation data. The results of the sensitivity and inverse modeling tests demonstrate the potential usefulness of WRF-CO2 4D-Var for regional CO2 inversions

Electric Pulses to Prepare Feeder Cells for Sustaining and Culturing of Undifferentiated Embryonic Stem Cells

Current challenges in embryonic-stem-cell (ESC) research include inability of sustaining and culturing of undifferentiated ESCs over time. Growth-arrested feeder cells are essential to the culture and sustaining of undifferentiated ESCs, and they are currently prepared using gammaradiation and chemical inactivation. Both techniques have severe limitations. In this study, we developed a new, simple and effective technique (pulsed-electric-fields, PEFs) to produce viable growth-arrested cells (RTS34st) and used them as high-quality feeder cells to culture and sustain undifferentiated zebrafish ESCs over time. The cells were exposed to 25 sequential 10- nanosecond-electric-pulses (10nsEPs) of 25, 40 and 150 kV/cm with 1s pulse interval, or 2 sequential 50-microsecond-electric-pulses (50μsEPs) of 2.83, 1.78 and 0.7 kV/cm with 5s pulse interval, respectively. We found that cellular effects of PEFs depended directly upon the duration, number and electric-field-strength (E) of the pulses, showing the feasibility of tuning them to produce various types of growth-arrested cells for culturing undifferentiated ESCs. Either 10nsEPs of 40 kV/cm or 50μsEPs of 1.78 kV/cm provided by inexpensive and widely available conventional electroporators, generated high-quality growth-arrested feeder cells for proliferation of undifferentiated ESCs over time. One can now use PEFs to replace radiation methods for preparation of growth-arrested feeder cells for advancing ESC research

Real-Time in vivo Imaging of Size-Dependent Transport and Toxicity of Gold Nanoparticles in Zebrafish Embryos Using Single Nanoparticle Plasmonic Spectroscopy

Noble metal nanoparticles (NPs) show distinctive plasmonic optical properties and superior photostability, enabling them to serve as photostable multicoloured optical molecular probes and sensors for real-time in vivo imaging. To effectively study biological functions in vivo, it is essential that the NP probes are biocompatible and can be delivered into living organisms non-invasively. In this study, we have synthesized, purified and characterized stable (non-aggregated) gold (Au) NPs (86.2 +/- 10.8 nm). We have developed dark-field single NP plasmonic microscopy and spectroscopy to study their transport into early developing zebrafish embryos (cleavage stage) and their effects on embryonic development in real-time at single NP resolution. We found that single Au NPs (75-97 nm) passively diffused into the embryos via their chorionic pore canals, and stayed inside the embryos throughout their entire development (120 h). The majority of embryos (96 +/- 3%) that were chronically incubated with the Au NPs (0-20 pM) for 120 h developed to normal zebrafish, while an insignificant percentage of embryos developed to deformed zebrafish (1 +/- 1)% or dead (3 +/- 3)%. Interestingly, we did not observe dose-dependent effects of the Au NPs (0-20 pM) on embryonic development. By comparing with our previous studies of smaller Au NPs (11.6 +/- 0.9 nm) and similar-sized Ag NPs (95.4 +/- 16.0 nm), we found that the larger Au NPs are more biocompatible than the smaller Au NPs, while the similar-sized Ag NPs are much more toxic than Au NPs. This study offers in vivo assays and single NP microscopy and spectroscopy to characterize the biocompatibility and toxicity of single NPs, and new insights into the rational design of more biocompatible plasmonic NP imaging probes

Measuring and modeling the perception of natural and unconstrained gaze in humans and machines

Humans are remarkably adept at interpreting the gaze direction of other individuals in their surroundings. This skill is at the core of the ability to engage in joint visual attention, which is essential for establishing social interactions. How accurate are humans in determining the gaze direction of others in lifelike scenes, when they can move their heads and eyes freely, and what are the sources of information for the underlying perceptual processes? These questions pose a challenge from both empirical and computational perspectives, due to the complexity of the visual input in real-life situations. Here we measure empirically human accuracy in perceiving the gaze direction of others in lifelike scenes, and study computationally the sources of information and representations underlying this cognitive capacity. We show that humans perform better in face-to-face conditions compared with recorded conditions, and that this advantage is not due to the availability of input dynamics. We further show that humans are still performing well when only the eyes-region is visible, rather than the whole face. We develop a computational model, which replicates the pattern of human performance, including the finding that the eyes-region contains on its own, the required information for estimating both head orientation and direction of gaze. Consistent with neurophysiological findings on task-specific face regions in the brain, the learned computational representations reproduce perceptual effects such as the Wollaston illusion, when trained to estimate direction of gaze, but not when trained to recognize objects or faces.This work was supported by the Center for Brains, Minds and Machines (CBMM), funded by NSF STC award CCF – 1231216

Size-Dependent Inhibitory Effects of Antibiotic Drug Nanocarriers Against Pseudomonas Aeruginosa

Multidrug membrane transporters (efflux pumps) are responsible for multidrug resistance (MDR) and the low efficacy of therapeutic drugs. Noble metal nanoparticles (NPs) possess a high surface-area-to-volume ratio and size-dependent plasmonic optical properties, enabling them to serve both as imaging probes to study sized-dependent MDR and as potential drug carriers to circumvent MDR and enhance therapeutic efficacy. To this end, in this study, we synthesized three different sizes of silver nanoparticles (Ag NPs), 2.4 ± 0.7, 13.0 ± 3.1, and 92.6 ± 4.4 nm, functionalized their surface with a monolayer of 11-amino-1-undecanethiol (AUT), and covalently conjugated them with antibiotics (ofloxacin, Oflx) to prepare antibiotic drug nanocarriers with conjugation ratios of 8.6 × 102, 9.4 × 103, and 6.5 × 105 Oflx molecules per NP, respectively. We purified and characterized the nanocarriers and developed cell culture medium in which the cells grew normally and the nanocarriers were stable (non-aggregated), to quantitatively study the size, dose, and efflux pump (MexAB-OprM) dependent inhibitory effect of the nanocarriers against two strains of Pseudomonas aeruginosa, WT (normal expression of MexAB-OprM) and ΔABM (deletion of MexAB-OprM). We found that the inhibitory effect of these nanocarriers highly depended on the sizes of NPs, the doses of antibiotic, and the expression of MexAB-OprM. The same amount of Oflx on the largest nanocarriers (92.6 ± 4.4 nm) showed the highest inhibitory effect (the lowest minimal inhibitory concentration) against P. aeruginosa. Surprisingly, the smallest nanocarriers (2.4 ± 0.7 nm) exhibited a lower inhibitory effect than free Oflx. The results suggest that size-dependent multivalent effects, the distribution and localization of Oflx (pharmacodynamics), and the efflux of Oflx all play a role in the inhibitory effects. Control experiments using three sizes of AgMUNH2 NPs (absence of Oflx) showed that these NPs do not exhibit any significant inhibitory activity toward both strains. These new findings demonstrate the need for and possibility of designing optimal sized antibiotic nanocarriers to achieve the highest efficacy against P. aeruginosa

A Quantitative Assay for Insulin-expressing Colony-forming Progenitors

The field of pancreatic stem and progenitor cell biology has been hampered by a lack of in vitro functional and quantitative assays that allow for the analysis of the single cell. Analyses of single progenitors are of critical importance because they provide definitive ways to unequivocally demonstrate the lineage potential of individual progenitors. Although methods have been devised to generate "pancreatospheres" in suspension culture from single cells, several limitations exist. First, it is time-consuming to perform single cell deposition for a large number of cells, which in turn commands large volumes of culture media and space. Second, numeration of the resulting pancreatospheres is labor-intensive, especially when the frequency of the pancreatosphere-initiating progenitors is low. Third, the pancreatosphere assay is not an efficient method to allow both the proliferation and differentiation of pancreatic progenitors in the same culture well, restricting the usefulness of the assay

Using mixture models to characterize disease-related traits

We consider 12 event-related potentials and one electroencephalogram measure as disease-related traits to compare alcohol-dependent individuals (cases) to unaffected individuals (controls). We use two approaches: 1) two-way analysis of variance (with sex and alcohol dependency as the factors), and 2) likelihood ratio tests comparing sex adjusted values of cases to controls assuming that within each group the trait has a 2 (or 3) component normal mixture distribution. In the second approach, we test the null hypothesis that the parameters of the mixtures are equal for the cases and controls. Based on the two-way analysis of variance, we find 1) males have significantly (p < 0.05) lower mean response values than females for 7 of these traits. 2) Alcohol-dependent cases have significantly lower mean response than controls for 3 traits. The mixture analysis of sex-adjusted values of 1 of these traits, the event-related potential obtained at the parietal midline channel (ttth4), found the appearance of a 3-component normal mixture in cases and controls. The mixtures differed in that the cases had significantly lower mean values than controls and significantly different mixing proportions in 2 of the 3 components. Implications of this study are: 1) Sex needs to be taken into account when studying risk factors for alcohol dependency to prevent finding a spurious association between alcohol dependency and the risk factor. 2) Mixture analysis indicates that for the event-related potential "ttth4", the difference observed reflects strong evidence of heterogeneity of response in both the cases and controls

Predictors of biologic treatment of psoriasis : a non-interventional study

Biologic therapies represent a significant advance in the treatment of psoriasis. However, no studies have examined the patient characteristics predictive of biologic treatment of psoriasis. The purpose of this study was to ascertain the frequency and predictors of treatment of psoriasis with biologics in three European countries, ie, France, Spain, and the UK. This was a cross-sectional analysis of physician-recorded demographic and clinical data on patients receiving either conventional or biologic treatments for psoriasis. Data were drawn from the Adelphi 2007 Psoriasis Disease Specific Program (DSP®), a multinational, real-world survey of patients with psoriasis consulting practicing dermatologists. The numbers of patients treated with biologic and nonbiologic agents were recorded. Data were subjected to bivariate analysis according to treatment regimen (biologic versus nonbiologic). Predictors of treatment with biologics were identified by logistic regression analysis. A total of 2,509 psoriasis patients were included in this study (1,374 from France, 561 from Spain, and 574 from the UK). Biologic use was most prevalent in Spain (19.4% of patients), followed by the UK (9.1%), and France (8.4%). In the logistic regression analysis, psoriatic arthritis was a statistically significant predictor of increased biologic use in France (odds ratio [OR] 5.38, 95% confidence interval [CI] 3.32-8.77), Spain (OR 2.71, 95% CI 1.16-6.33), and the UK (OR 8.70, 95% CI 3.65-20.83). Physician-assessed moderate-to-severe disease was also a statistically significant predictor of increased biologic use in France (OR 5.08, 95% CI 2.01-12.82), Spain (OR 11.11, 95% CI 4.33-28.57), and the UK (OR 8.55, 95% CI 1.11-66.67). In this study, an average of about one tenth of psoriasis patients enrolled in Spain, France, and the UK were treated with biologics in 2007. Physician-assessed moderate-to-severe disease and presence of psoriatic arthritis were significantly associated with biologic use in all three countries