Modification of porous poly(ether sulfone) membranes by low‐temperature CO2‐plasma treatment

A general method of modifying the entire cross section of porous poly(ether sulfone) membranes with a low‐temperature CO₂‐plasma treatment is reported. Both surfaces of the membranes are highly hydrophilic, with a water drop on the surface disappearing in less than 1 s, even 6 months after plasma treatment. This high hydrophilicity of both membrane surfaces results from the incorporation of hydrophilic functionalities, as evidenced by Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy. The incorporation of these hydrophilic functionalities takes place primarily during plasma treatment, with some incorporation of atmospheric oxygen and nitrogen immediately upon exposure to air. Scanning electron microscopy shows that the membrane surface is covered by a thin, white layer that is likely the result of etching and redeposition of sputtered surface fragments. An increase in the water bubble point and glass‐transition temperature is also observed for CO₂‐plasma‐treated membranes. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2473–2488, 2002     

Inclusive Science Education: Classroom Teacher and Science Educator Experiences in CLASS Workshops

Inclusion is the meaningful participation of students with disabilities in general education classrooms. The CLASS project (Creating Laboratory Access for Science Students) is a unique initiative offering training and resources to help educators provide students with a variety of physical, sensory and learning disabilities equal access in the science laboratory or field. To determine whether participants believed a 2‐week residential workshop sponsored by CLASS raised disability awareness and provided teacher training in inclusive science teaching practice, a multipoint Likert scale survey and questionnaire was completed by all participants (N= 20) in four workshops. Participants reported large gains in their preparedness to teach science to students with disabilities. Participants also reported gains in their familiarity with instructional strategies, curricula, and resources and their ability to design, select, and modify activities for students with disabilities. Finally, shifts in attitudes about teaching science to students with disabilities were noted.     

Assessment of dual plane PIV measurements in wall turbulence using DNS data

Experimental dual plane particle image velocimetry (PIV) data are assessed using direct numerical simulation (DNS) data of a similar flow with the aim of studying the effect of averaging within the interrogation window. The primary reason for the use of dual plane PIV is that the entire velocity gradient tensor and hence the full vorticity vector can be obtained. One limitation of PIV is the limit on dynamic range, while DNS is typically limited by the Reynolds number of the flow. In this study, the DNS data are resolved more finely than the PIV data, and an averaging scheme is implemented on the DNS data of similar Reynolds number to compare the effects of averaging inherent to the present PIV technique. The effects of averaging on the RMS values of the velocity and vorticity are analyzed in order to estimate the percentage of turbulence intensity and enstrophy captured for a given PIV resolution in turbulent boundary layers. The focus is also to identify vortex core angle distributions, for which the two-dimensional and three-dimensional swirl strengths are used. The studies are performed in the logarithmic region of a turbulent boundary layer at z ⁺ = 110 from the wall. The dual plane PIV data are measured in a zero pressure gradient flow over a flat plate at Re _τ = 1,160, while the DNS data are extracted from a channel flow at Re _τ = 934. Representative plots at various wall-normal locations for the RMS values of velocity and vorticity indicate the attenuation of the variance with increasing filter size. Further, the effect of averaging on the vortex core angle statistics is negligible when compared with the raw DNS data. These results indicate that the present PIV technique is an accurate and reliable method for the purposes of statistical analysis and identification of vortex structures.     

Evaluation of direct analysis in real time mass spectrometry for onsite monitoring of batch slurry reactions

Batch slurry reactions are widely used in the industrial manufacturing of chemicals, pharmaceuticals, petrochemicals and polymers. However, onsite monitoring of batch slurry reactions is still not feasible in production plants due to the challenge in analyzing heterogeneous samples without complicated sample preparation procedures. In this study, direct analysis in real time mass spectrometry (DART-MS) has been evaluated for the onsite monitoring of a model batch slurry reaction. The results suggested that automation of the sampling process of DART-MS is important to achieve quantitative results. With a sampling technique of manual sample deposition on melting point capillaries followed by automatic sample introduction across the helium beam, relative standard deviation (RSD) of the protonated molecule signals from the reaction product of the model batch slurry reaction ranged from 6 to 30%. This RSD range is improved greatly over a sampling technique of manual sample deposition followed by manual sample introduction where the RSDs are up to 110%. Furthermore, with the semi-automated sampling approach, semi-quantitative analysis of slurry samples has been achieved. Better quantification is expected with a fully automated sampling approach.     

A Comparison of Concrete and Virtual Manipulative Use in Third‐ and Fourth‐Grade Mathematics

The primary purpose of this classroom experiment was to examine the effectiveness of concrete (hands‐on) manipulatives as compared with virtual (computer‐based) manipulatives on student review of fraction concepts in third grade and introduction of symmetry concepts in fourth grade. A pretest–posttest design was employed with a sample of 91 third‐grade students and 54 fourth‐grade students who were randomly assigned to complete a lesson using either concrete or virtual manipulatives. Students used a variety of manipulative materials during the lessons. Results of the posttest suggest that student learning was unchanged by lesson condition.     

Design, synthesis, and biological evaluation of diminutive forms of (+)-spongistatin 1: lessons learned

The design, synthesis, and biological evaluation of two diminutive forms of (+)-spongistatin 1, in conjunction with the development of a potentially general design strategy to simplify highly flexible macrocyclic molecules while maintaining biological activity, have been achieved. Examination of the solution conformations of (+)-spongistatin 1 revealed a common conformational preference along the western perimeter comprising the ABEF rings. Exploiting the hypothesis that the small-molecule recognition/binding domains are likely to comprise the conformationally less mobile portions of a ligand led to the design of analogues, incorporating tethers (blue) in place of the CD and the ABCD components of the (+)-spongistatin 1 macrolide, such that the conformation of the retained (+)-spongistatin 1 skeleton would mimic the assigned solution conformations of the natural product. The observed nanomolar cytotoxicity and microtubule destabilizing activity of the ABEF analogue provide support for both the assigned solution conformation of (+)-spongistatin 1 and the validity of the design strategy.