Density Functional Theory Studies on the Relative Reactivity of Chloroethenes on Zerovalent Iron.

This study investigated the adsorption and dissociation of perchloroethene (PCE), trichloroethene (TCE), and cis-dichloroethene (cis-DCE) on zerovalent iron. The mechanisms by which iron decomposes chlorinated solvents by catalytic cleavage of the carbon-chlorine bond, are as not yet well understood. To develop process models for the optimal design of in situ and ex situ zerovalent iron treatment systems for the removal of chlorinated solvents from drinking water supplies, it is important to understand these mechanisms, and in particular how the degree of chlorination of the contaminant affects its reactivity on the iron surface. Periodic density functional theory (DFT) and the generalized gradient approximation (GGA) were used to determine the most thermodynamically favorable site on Fe(110) for the adsorption of all three chloroethenes. Climbing image nudged elastic band (CI-NEB) method with the periodic DFT and the GGA was employed to calculate activation energies of the chloroethene compounds according to the principal dechlorination mechanism of reductive β-elimination. The dechlorination rate constants of the chloroethenes were estimated using an Arrhenius equation with theoretically calculated vibrational frequencies of the compounds. Of the adsorption sites examined, an atop site, where the chloroethene C=C bond straddles a surface iron atom, was the most energetically favorable site for the adsorption of all three chloroethenes. Electronic structure and property analyses demonstrate the strong hybridization of the π-bonding orbital between the chloroethene C=C bond and the iron surface suggesting that adsorbed chloroethenes are strongly activated on Fe(110) and are likely precursors for subsequent chloroethene dissociation on the Fe surface. Taking into account the effect of solvation indirectly, the ordering of the adsorption energies of chloroethenes from the aqueous phase onto Fe(110) is in agreement with experimental observation (PCE > TCE > cis-DCE). Chloroethenes with a higher number of chlorine atoms have lower activation energies than those with fewer number of chlorine atoms. The activation energies of PCE, TCE, and cis-DCE at their rate-limiting steps are 9.9, 16.6, and 23.8 kJ/mol, respectively. At room temperature (300 K), for example, the dechlorination rate of PCE is 14 times and 338 times faster than those of TCE and cis-DCE, respectively.Ph.D.Environmental EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/61730/1/limkr_1.pd

Elastography Can Effectively Decrease the Number of Fine-Needle Aspiration Biopsies in Patients with Calcified Thyroid Nodules

AbstractWhen calcification, frequently found in both benign and malignant nodules, is present in thyroid nodules, non-invasive differentiation with ultrasound becomes challenging. The goal of this study was to evaluate the utility of elastography in differentiating calcified thyroid nodules. Consecutive patients (165 patients with 196 nodules) referred for fine-needle aspiration who had undergone both ultrasound elastography and B-mode examinations were analyzed retrospectively. Calcification was present in 45 benign and 20 malignant nodules. On 65 calcified nodules, elastography had 95% sensitivity, 51.1% specificity, 46.3% positive predictive value and 95.8% negative predictive value in detecting malignancy. Twenty-three of 45 benign calcified nodules were correctly diagnosed with elastography compared with 4 of 45 by B-mode ultrasound. Although it is difficult to differentiate benign and malignant calcified thyroid nodules solely with B-mode ultrasound, elastography has the potential to reduce the number of fine-needle aspiration biopsies performed on calcified nodules

Method and an apparatus for processing a signal

A method of processing a signal is disclosed. The present invention includes receiving a maximum number of band and a code value of at least one section length, calculating a bit number corresponding to the code value of the at least one section length using the maximum number of the band, and obtaining the section length information by decoding the code value of the section length based on the bit number. A method of processing a signal is disclosed. The present invention includes receiving factor information of a current frame, receiving flag information indicating whether a coding mode of the factor information is an absolute value mode or a relative value mode, and obtaining factor data of the current frame using factor data of a previous frame and the received factor information based on the flag information

Methods and apparatuses for encoding and decoding object-based audio signals

Provided are an audio encoding method and apparatus and an audio decoding method and apparatus in which audio signals can be encoded or decoded so that sound images can be localized at any desired position for each object audio signal. The audio decoding method generating a third downmix signal by combining a first downmix signal extracted from a first audio signal and a second downmix signal extracted from a second audio signal; generating third object-based side information by combining first object-based side information extracted from the first audio signal and second object-based side information extracted from the second audio signal; converting the third object-based side information into channel-based side information; and generating a multi-channel audio signal using the third downmix signal and the channel-based side information

Fabrication of core/shell ZnWO4/carbon nanorods and their Li electroactivity

Carbon-coated ZnWO4 [C-ZW] nanorods with a one-dimensional core/shell structure were synthesised using hydrothermally prepared ZnWO4 and malic acid as precursors. The effects of the carbon coating on the ZnWO4 nanorods are investigated by thermogravimetry, high-resolution transmission electron microscopy, and Raman spectroscopy. The coating layer was found to be in uniform thickness of approximately 3 nm. Moreover, the D and G bands of carbon were clearly observed at around 1,350 and 1,600 cm-1, respectively, in the Raman spectra of the C-ZW nanorods. Furthermore, lithium electroactivities of the C-ZW nanorods were evaluated using cyclic voltammetry and galvanostatic cycling. In particular, the formed C-ZW nanorods exhibited excellent electrochemical performances, with rate capabilities better than those of bare ZnWO4 nanorods at different current rates, as well as a coulombic efficiency exceeding 98%. The specific capacity of the C-ZW nanorods maintained itself at approximately 170 mAh g-1, even at a high current rate of 3 C, which is much higher than pure ZnWO4 nanorods

Nb-doped TiO2 air-electrode for advanced Li-air batteries

As new substrate materials to replace a conventional carbon substrate, TiO2 and Nb-doped TiO2 air-electrodes for Li-air batteries were investigated. Through a simple two-step process, we successfully synthesized anatase Nb-doped TiO2 nanoparticles and demonstrated the potential applicability of TiO2-based materials for use in Li-air battery electrode. An air-electrode with Nb-doped TiO2 nanoparticles could deliver a higher discharge capacity than a bare TiO2 electrode due to the enhanced conductivity, which implies the importance of facile electron transport during the discharge process. © 2014 The Ceramic Society of Japan and the Korean Ceramic Society.

Effects of physical activity participation on cognitive impairment in older adults population with disabilities

BackgroundExisting research on the association between cognitive function and physical activity in the older adults population with disabilities is limited. Additionally, there is a need to explore avenues for enhancing the longevity and quality of life among these individuals.ObjectiveThis study aimed to investigate the independent and joint associations between cognitive function and levels of physical activity in the older adults population with disabilities.MethodsA total of 315 older adults adults (men = 182, women = 133), identified with disabilities based on medical evaluation, were recruited from the first survey of the Korean Longitudinal Study of Aging (KLoSA). Participants underwent assessments for cognitive function, physical activity (PA), activities of daily living (ADLs), instrumental activities of daily living (IADLs), and grip strength.ResultsADLs (p < 0.001) and IADLs (p < 0.001) scores were significantly higher in the male normal cognitive group compared to both the male and female cognitive impairment groups. In an unadjusted model, disabled older adults individuals who did not meet the recommended PA guidelines showed an increased odds ratio for cognitive dysfunction (OR = 2.29, 95% CI = 1.32–3.97). Those participating in PA at least 1 day per week also demonstrated an elevated odds ratio (OR = 1.22, 95% CI = 1.08–1.38) for cognitive dysfunction compared to those who engaged in regular PA. A negative correlation was observed between K-MMSE scores and grip strength (r = 0.448, p < 0.001).ConclusionThis study provides robust evidence that disabled older adults individuals who do not meet the recommended guidelines for PA or who do not participate in PA at least once a week have an increased likelihood of cognitive impairment compared to those who are regularly active