5-Chloro-1-phenyl-1H-tetra­zole

The tetra­zole and phenyl rings of the title compound, C7H5ClN4, form a dihedral angle 64.5°

Effects of benthic algae on release of soluble reactive phosphorus from sediments: a radioisotope tracing study

AbstractTo evaluate the effect of benthic algae on soluble reactive phosphorus (SRP) release from sediments in shallow lakes, experiments on SRP release with and without benthic algae in sediment cores and an experiment on SRP uptake by benthic algae were conducted using the radioisotope (32P) tracing method. The dissolved oxygen (DO) concentration in sediment cores was also investigated. The results show that benthic algae effectively reduce the release of SRP from sediments to overlying water. The uptake of SRP by benthic algae, which is the direct way in which benthic algae affect the SRP release from sediments, is low in filtered water and increases with the SRP concentration. However, in the experiment, the increased uptake rate lasted for a short time (in one hour), and after that it returned to a low rate. Benthic algae make the DO concentration and the oxic layer thickness increased, which can indirectly reduce the SRP release from sediments. These findings indicate that benthic algae can reduce the SRP release from sediments in both direct and indirect ways. It seems that the indirect way also plays an important role in reducing the SRP release from sediments

Students' Motivation, Perspectives, and Learning in Flipped University Classrooms

The flipped classroom, introduced by Jonathan Bergmann and Aaron Sams in 2008, has been a popular instructional strategy that promotes active learning. In a flipped classroom, the learning content is provided to students before class, and class time is dedicated to engaging students in student-centered activities that reinforce and integrate the knowledge. This dissertation aims to explore the relationship between motivation and students' perspectives, learning performance, and use of online course materials in flipped classrooms. Fifty-nine undergraduate students enrolled in flipped classes completed a survey soliciting their motivation, as defined by the Expectancy-Value theory, and their perceptions of the flipped course. Students' expectancy beliefs (control beliefs about learning, self-efficacy) and value beliefs (task value, intrinsic motivation, extrinsic motivation) were measured by subscales adopted from Motivated Strategies for Learning Questionnaire (MSLQ). Students' final grade percentage represented their learning performance. Brightspace log data were obtained to evaluate students' use of online materials. Results indicated that motivation had an effect on students learning in flipped classroom environments. Students have similar motivation patterns regarding their learning performance in flipped classrooms as in traditional or online classrooms. Regression analyses indicated self-efficacy is a significant predictor of both students' academic achievement and perceptions of the flipped classroom. Overall, students had positive attitudes towards the flipped model but indicated neutral attitudes when asked if they wished more instructors used the flipped classroom model. This study adds to the literature for understanding students' motivation in flipped educational settings and suggests implications foreffective teaching in a flipped classroom. Although the flipped classroom may change the teacher's role from "sage on the stage" to a "guide on the side," (King, 1993) the teacher's role in the learning environment remains vitally important.Educational Technolog

Dichlorido[(1R,2R)-N-(pyridin-2-yl­methyl)cyclo­hexane-1,2-diamine-κ3 N,N′,N′′]mercury(II)

In the title compound, [HgCl2(C12H19N3)], the HgII ion is coordinated by three N atoms of the (1R,2R)-N-(pyridin-2-ylmeth­yl)cyclo­hexane-1,2-diamine ligand and by a Cl atom in the basal plane, and by a second Cl atom in the apical position, within a distorted square-pyramidal geometry. The coordination of the enanti­opure ligand to the metal atom renders the central N atom chiral with an S configuration, so the complex is enanti­omerically pure and corresponds to the S,R,R diastereoisomer. Mol­ecules are linked via weak N—H⋯Cl hydrogen bonds into a one-dimensional hydrogen-bonding supramolecular chain along the crystallographic b axis

Distribution of ocular parameters measured by optical coherence tomography in a childhood population.

Purpose: To document the distribution of macular, retinal nerve fibre layer (RNFL) thickness and optic disc parameters, as measured using optical coherence tomography (OCT) in a population-based sample of young persons and to examine the relationship of these measurements to ocular variables (spherical equivalent refraction [SER] and axial length) and systemic variables (age, gender, anthropometry, ethnicity and birth parameters). Methods: A stratified random cluster sample of 6- and 12-year-old school students from across the Sydney metropolitan region were surveyed and examined using non-contact methods (including biometric measurements with the IOL Master and Canon RK-F1) to determine axial length and SER. The 3rd generation Optical Coherence Tomography instrument (Zeiss Stratus OCT, Dublin, CA, USA) was used to measure macular and RNFL thickness and major optic disc parameters in this sample. Ethnicity and birth parameters were derived using questionnaires. Anthropometric parameters, such as height and weight, were measured using standard methods. Results: The thickness of the foveal, central, inner macular, outer macular and macular volume parameters was normally distributed in both age cohorts. The temporal quadrant was thinner than all other quadrants at both the inner and outer macular regions. The central and inner macula was significantly thicker in boys than in girls, and in Caucasian than in East Asian children. The inner and outer macular regions were slightly, but significantly, thinner with increasing axial length, or myopic refraction. On the other hand, these corresponding regions were significantly thicker with more hyperopic SER. RNFL thickness and RNFLestimated integral were normally distributed in both age groups. RNFL thickness was thinnest for the temporal quadrant, followed by the nasal, inferior, and superior quadrants. RNFL average thickness was marginally greater in boys than in girls and in East Asian than in Caucasian children. The RNFL was thinner with both greater axial length and less hyperopic refractions. Optic disc, optic cup and neural rim parameters were also normally distributed in this young population. In analyses that adjusted for potential confounders, optic disc area increased significantly with axial length and refraction. Neural rim area increased with axial length. There were minimal gender differences in the two age groups. Most optic disc and optic cup dimensions were significantly larger in East Asian than in Caucasian and Middle Eastern children. The foveal minimum and overall RNFL thickness were similar in both age cohorts, while other retinal regions and optic disc size were slightly larger in the 12- than the 6-year-old children. Amblyopic eyes had greater foveal minimum thickness than the normal fellow eye of individual children and the right eyes of non-amblyopic children. Birth weight and head circumference were positively correlated with both RNFL and macular thickness. Conclusions: Macular thickness, RNFL thickness and optic disc parameters were normally distributed in these two age groups of children. Axial length and refraction were important ocular biometric determinants of macular thickness and RNFL thickness. Significant ethnic differences were also demonstrated. RNFL average thickness was also positively associated with optic disc area. Central macular thickness increased in amblyopia. These findings have implications for the interpretation of OCT measurements in research and clinical practice in both children and adult

Synthesis of NaYF4:Yb3+, Er3+ upconversion nanoparticles in normal microemulsions

An interface-controlled reaction in normal microemulsions (water/ethanol/sodium oleate/oleic acid/n-hexane) was designed to prepare NaYF4:Yb3+, Er3+ upconversion nanoparticles. The phase diagram of the system was first studied to obtain the appropriate oil-in-water microemulsions. Transmission electron microscopy and X-ray powder diffractometer measurements revealed that the as-prepared nanoparticles were spherical, monodisperse with a uniform size of 20 nm, and of cubic phase with good crystallinity. Furthermore, these nanoparticles have good dispersibility in nonpolar organic solvents and exhibit visible upconversion luminescence of orange color under continuous excitation at 980 nm. Then, a thermal treatment for the products was found to enhance the luminescence intensity. In addition, because of its inherent merit in high yielding and being economical, this synthetic method could be utilized for preparation of the UCNPs on a large scale

Inhibitory Effect of Phthalic Acid on Tyrosinase: The Mixed-Type Inhibition and Docking Simulations

Tyrosinase inhibition studies are needed due to the medicinal applications such as hyperpigmentation. For probing effective inhibitors of tyrosinase, a combination of computational prediction and enzymatic assay via kinetics was important. We predicted the 3D structure of tyrosinase, used a docking algorithm to simulate binding between tyrosinase and phthalic acid (PA), and studied the reversible inhibition of tyrosinase by PA. PA inhibited tyrosinase in a mixed-type manner with a Ki = 65.84 ± 1.10 mM. Measurements of intrinsic and ANS-binding fluorescences showed that PA induced changes in the active site structure via indirect binding. Simulation was successful (binding energies for Dock6.3 = −27.22 and AutoDock4.2 = −0.97 kcal/mol), suggesting that PA interacts with LEU73 residue that is predicted commonly by both programs. The present study suggested that the strategy of predicting tyrosinase inhibition based on hydroxyl groups and orientation may prove useful for screening of potential tyrosinase inhibitors

Design of Virtual Objects Using Transformation Optics

Two structures of virtual targets filled with metamaterials are investigated through transformation optics to tailor the specific electromagnetic fields into desired spatial patterns. One virtual structure is a square column object transformed from a dielectric cylinder and the other virtual structure is a cylinder object transformed from a dielectric square column. Because the electromagnetic parameters in the virtual objects are obtained from real objects by the method of transformation optics, the scattering fields of virtual structures are the same as those of the real objects. The numerical simulations further prove the correction of theoretical results