Effect of Compression Wood on Leaching and Fixation of CCA-C Treated Red Pine

In this study, we investigated the effect of compression wood on the release rate of chromium, copper, and arsenic elements from red pine (Pinus resinosa Ait.) and the rate of fixation of hexavalent chromium in the wood. Wood blocks from red pine, some containing compression wood and some with normal wood, were treated with a 1.0% CCA-C solution and then allowed to fix at 23°C ± 2 (74°F ± 4) for 0, 6, 24, 48, 96, 192, and 336 h. After each fixation period, sets of blocks removed from the conditioning room were subjected to 336 h of leaching. The percentage of hexavalent chromium reduced to the trivalent state was determined for solution pressed from matched sets of blocks. The blocks containing compression wood released significantly less chromium and copper elements. For chromium, the biggest effect was seen after the 192- and 336-h fixation periods. In the normal wood blocks fixed for 336 h, the average chromium release rate after 6 h of leaching was almost five times greater than that of the compression wood blocks. Copper and arsenic release was also affected by compression wood, but for these two elements, the effect diminished during the later stages of fixation. A higher percentage of hexavalent chromium was reduced to trivalent chromium in compression wood compared with that in normal wood after most fixation periods, and this difference was significant after 0, 48, 96, and 192 h

Characterization of ageing resistant transparent nanocrystalline yttria-stabilized zirconia implants.

The "Window to the Brain" is a transparent cranial implant under development, based on nanocrystalline yttria-stabilized zirconia (nc-YSZ) transparent ceramic material. Previous work has demonstrated the feasibility of this material to facilitate brain imaging over time, but the long-term stability of the material over decades in the body is unknown. In this study, the low-temperature degradation (LTD) of nc-YSZ of 3, 6, and 8 mol % yttria is compared before and after accelerated ageing treatments following ISO standards for assessing the ageing resistance of zirconia ceramics. After 100 hr of accelerated ageing (equivalent to many decades of ageing in the body), the samples do not show any signs of phase transformation to monoclinic by X-ray diffraction and micro-Raman spectroscopy. Moreover, the mechanical hardness of the samples did not decrease, and changes in optical transmittance from 500 to 1000 nm due to ageing treatments was minimal (below 3% for all samples), and unlikely to be due to phase transformation of surface crystals to monoclinic. These results indicate the nc-YSZ has excellent ageing resistance and can withstand long-term implantation conditions without exhibiting LTD

Enhanced near infrared optical access to the brain with a transparent cranial implant and scalp optical clearing.

We report on the enhanced optical transmittance in the NIR wavelength range (900 to 2400 nm) offered by a transparent Yttria-stabilized zirconia (YSZ) implant coupled with optical clearing agents (OCAs). The enhancement in optical access to the brain is evaluated upon comparing ex-vivo transmittance measurements of mice native skull and the YSZ cranial implant with scalp and OCAs. An increase in transmittance of up to 50% and attenuation lengths of up to 2.4 mm (i.e., a five-fold increase in light penetration) are obtained with the YSZ implant and the OCAs. The use of this ceramic implant and the biocompatible optical clearing agents offer attractive features for NIR optical techniques for brain theranostics

A computer-based selective visual attention test for first-grade school children: Design, development and psychometric properties

Background: Visual attention is known as a critical base for learning. The purpose of the present study was to design, develop and evaluate the test-retest and internal consistency reliability as well as face, content and convergent validity of the computer- based selective visual attention test (SeVAT) for healthy first-grade school children. Methods: In the first phase of this study, the computer-based SeVAT was developed in two versions of original and parallel. Ten experts in occupational therapy helped to measure the content validity using the CVR and CVI methods. Face validity was measured through opinions collected from 10 first-grade children. The convergent validity of the test was examined using the Spearman correlation between the SeVAT and Stroop test. In addition, test-retest reliability was determined by measuring the intra-class correlation (ICC) between the original and parallel versions of the SeVAT in a single session. The internal consistency was calculated by Cronbach's alpha coefficients. Sixty first grade children (30 girls/30boys) participated in this study. Results: The developed test was found to have good content and face validity. The SeVAT showed an excellent test-retest reliability (ICC= 0.778, p<0.001) and internal consistency (Cronbach's Alpha of original and parallel tests were 0.857 and 0.831, respectively). SeVAT and Stroop test demonstrated a positive correlation upon the convergent validity testing. Conclusion: Our results suggested an acceptable reliability and validity for the computer-based SeVAT in the assessment of selective attention in children. Further research may warrant the differential validity of such a test in other age groups and neuro-cognitively disordered populations

A Molecular Line Observation toward Massive Clumps Associated with Infrared Dark Clouds

We have surveyed the N2H+ J=1-0, HC3N J=5-4, CCS J_N=4_3-3_2, NH3 (J, K) = (1, 1), (2, 2), (3, 3), and CH3OH J=7-6 lines toward the 55 massive clumps associated with infrared dark clouds by using the Nobeyama Radio Observatory 45 m telescope and the Atacama Submillimeter Telescope Experiment 10 m telescope. The N2H+, HC3N, and NH3 lines are detected toward most of the objects. On the other hand, the CCS emission is detected toward none of the objects. The [CCS]/[N2H+] ratios are found to be mostly lower than unity even in the Spitzer 24 micron dark objects. This suggests that most of the massive clumps are chemically more evolved than the low-mass starless cores. The CH3OH emission is detected toward 18 out of 55 objects. All the CH3OH-detected objects are associated with the Spitzer 24 micron sources, suggesting that star formation has already started in all the CH3OH-detected objects. The velocity widths of the CH3OH J_K=7_0-6_0 A+ and 7_{-1}-6_{-1} E lines are broader than those of N2H+ J=1-0. The CH3OH J_K=7_0-6_0 A+ and 7_{-1}-6_{-1} E lines tend to have broader linewidth in the MSX dark objects than in the others, the former being younger or less luminous than the latter. The origin of the broad emission is discussed in terms of the interaction between an outflow and an ambient cloud.Comment: Accepted to Ap