Panel Discussion: Creating A Spirit Of Inquiry In The Classroom

A paucity of published literature exists related to the use of panel discussion as a teaching strategy.  This article describes the panel discussion, the underpinnings of constructivism and the use of panel discussion to create a constructivist classroom environment.  Details of planning, evaluating, and challenges of a panel discussion are also provided

The Connectivity of the Human Pulvinar: A Diffusion Tensor Imaging Tractography Study

Previous studies in nonhuman primates and cats have shown that the pulvinar receives input from various cortical and subcortical areas involved in vision. Although the contribution of the pulvinar to human vision remains to be established, anatomical tracer and electrophysiological animal studies on cortico-pulvinar circuits suggest an important role of this structure in visual spatial attention, visual integration, and higher-order visual processing. Because methodological constraints limit investigations of the human pulvinar's function, its role could, up to now, only be inferred from animal studies. In the present study, we used an innovative imaging technique, Diffusion Tensor Imaging (DTI) tractography, to determine cortical and subcortical connections of the human pulvinar. We were able to reconstruct pulvinar fiber tracts and compare variability across subjects in vivo. Here we demonstrate that the human pulvinar is interconnected with subcortical structures (superior colliculus, thalamus, and caudate nucleus) as well as with cortical regions (primary visual areas (area 17), secondary visual areas (area 18, 19), visual inferotemporal areas (area 20), posterior parietal association areas (area 7), frontal eye fields and prefrontal areas). These results are consistent with the connectivity reported in animal anatomical studies

The Effect of Sn(IV) Chlorin e6 on HepG2 Cancer Cell Lines

This research investigated the effect of Sn(IV) chlorin e6 dichloride trisodium salt photosensitizer on the viability of HepG2 cancer cell lines in vitro. The effect of light on the viability of cells without the photosensitiser and the toxicity of the photosensitiser in the absence of light were examined in this research. No toxic effects with the absence of light were found and no photodamge effect on the cells without the presence of photosensitiser. The effect of different concentrations of the photosensitiser with fixed light dose of 70 J/cm2 on the viability of HepG2 cancer cells were performed. Then, two concentrations 25 and 30 μg/ml were investigated at different light doses 60-100 J/cm2. The effect of the photosensitiser on the viability of HepG2 at different light doses and different concentrations was found to have low viability over concentrations of 25 μg/ml. This could be due to that the photosensitiser reached a saturated status after this concentration. Key words: PDT; Sn(IV) chlorin e6; liver cancer; phototoxicity; viability assa

Long-lived optical phonons in ZnO studied with impulsive stimulated Raman scattering

The anharmonic properties of the low-frequency E2 phonon in ZnO were measured using impulsive stimulated Raman scattering. At 5 K, the frequency and lifetime are (2.9787 +/- 0.0002) THz and (211 +/- 7) ps. The unusually long lifetime and the high accuracy in the determination of the frequency hold promise for applications in metrology, quantum computation and materials characterization. The temperature dependence of the lifetime is determined by two-phonon up-conversion decay contributions, which vanish at zero temperature. Results suggest that the lifetime is limited by isotopic disorder and that values in the nanosecond range may be achievable in isotopically-pure samples

Spontaneous formation of liquid crystalline phases and phase transitions in highly concentrated plasmid DNA

The liquid crystalline (LC) properties of two supercoiled plasmid DNA samples, pBSK (2958 bp) and pGEM (3000 bp), have been studied using polarised light microscopy (PLM), circular dichroism (CD) and UV-Vis spectroscopy. The influence of methods of isolation on plasmid LC behaviour is described, and using PLM we have demonstrated the spontaneous formation of cholesteric fingerprint-like textures. Preliminary studies of LC phase transitions in pGEM show the irreversibility of LC phase formation, as a consequence of changes in the tertiary structure of supercoiled plasmids. Using UV-Vis spectroscopy a hyperchromic effect was observed with increasing temperature. The CD spectra clearly showed structural changes, and probably mismatching of DNA bases, during cooling. Finally, we have observed an irreversible phase transition in plasmid DNA which is very different from that previously reported in linear DNA

Spin chirality induced by the Dzyaloshinskii-Moriya interaction and the polarized neutron scattering

We discuss the influence of the Dzyaloshinskii-Moriya (DM) interaction in the Heizenberg spin chain model for the observables in the polarized neutron scattering experiments. We show that different choices of the parameters of DM interaction may leave the spectrum of the problem unchanged, while the observable spin-spin correlation functions may differ qualitatively. Particularly, for the uniform DM interaction one has the incommensurate fluctuations and polarization-dependent neutron scattering in the paramagnetic phase. We sketch the possible generalization of our treatment to higher dimensions.Comment: 4 pages, REVTEX, no figures, references added, to appear in PR

Optical Phonon Lasing in Semiconductor Double Quantum Dots

We propose optical phonon lasing for a double quantum dot (DQD) fabricated in a semiconductor substrate. We show that the DQD is weakly coupled to only two LO phonon modes that act as a natural cavity. The lasing occurs for pumping the DQD via electronic tunneling at rates much higher than the phonon decay rate, whereas an antibunching of phonon emission is observed in the opposite regime of slow tunneling. Both effects disappear with an effective thermalization induced by the Franck-Condon effect in a DQD fabricated in a carbon nanotube with a strong electron-phonon coupling.Comment: 8 pages, 4 figure

Improving Seventh Grade Students' Learning of Ratio and Proportion: The Role of Schema-Based Instruction

The present study evaluated the effectiveness of an instructional intervention (schema-based instruction, SBI) that was designed to meet the diverse needs of middle school students by addressing the research literatures from both special education and mathematics education. Specifically, SBI emphasizes the role of the mathematical structure of problems and also provides students with a heuristic to aid and self-monitor problem solving. Further, SBI addresses well-articulated problem solving strategies and supports flexible use of the strategies based on the problem situation. One hundred forty eight seventh-grade students and their teachers participated in a 10-day intervention on learning to solve ratio and proportion word problems, with classrooms randomly assigned to SBI or a control condition. Results suggested that students in SBI treatment classes outperformed students in control classes on a problem solving measure, both at posttest and on a delayed posttest administered 4 months later. However, the two groups' performance was comparable on a state standardized mathematics achievement test

High-pressure enzymatic hydrolysis to reveal physicochemical and thermal properties of bamboo fiber using a supercritical water fermenter

Bamboo fiber was treated using a high-pressure enzyme hydrolysis process. The process performance was compared with the pulping and bleaching process for bamboo fiber.Several analytical methods, including field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, and differential scanning calorimetry, were employed to determine the physicochemical and thermal properties of the treated cellulosic bamboo fiber. It was found that the pressurized enzyme hydrolysis treated bamboo fiber had the most uniform morphological structure, along with lowest crystallinity and highest thermal stability. Thus, utilizing high-pressure enzyme hydrolysis is the most effective process for treating fiber to remove non-cellulosic components from the raw material, including lignin, hemicelluloses, and waxy materials

Reading aloud boosts connectivity through the putamen

Functional neuroimaging and lesion studies have frequently reported thalamic and putamen activation during reading and speech production. However, it is currently unknown how activity in these structures interacts with that in other reading and speech production areas. This study investigates how reading aloud modulates the neuronal interactions between visual recognition and articulatory areas, when both the putamen and thalamus are explicitly included. Using dynamic causal modeling in skilled readers who were reading regularly spelled English words, we compared 27 possible pathways that might connect the ventral anterior occipito-temporal sulcus (aOT) to articulatory areas in the precentral cortex (PrC). We focused on whether the neuronal interactions within these pathways were increased by reading relative to picture naming and other visual and articulatory control conditions. The results provide strong evidence that reading boosts the aOT–PrC pathway via the putamen but not the thalamus. However, the putamen pathway was not exclusive because there was also evidence for another reading pathway that did not involve either the putamen or the thalamus. We conclude that the putamen plays a special role in reading but this is likely to vary with individual reading preferences and strategies