A Nanotubular Metal–Organic Framework with a Narrow Bandgap from Extended Conjugation**

A one-dimensional nanotubular metal–organic framework (MOF) [Ni(Cu-H₄TPPA)]⋅2 (CH₃)₂NH₂⁺ (H₈TPPA=5,10,15,20-tetrakis[p-phenylphosphonic acid] porphyrin) constructed by using the arylphosphonic acid H₈TPPA is reported. The structure of this MOF, known as GTUB-4 , was solved by using single-crystal X-ray diffraction and its geometric accessible surface area was calculated to be 1102 m² g⁻¹, making it the phosphonate MOF with the highest reported surface area. Due to the extended conjugation of its porphyrin core, GTUB-4 possesses narrow indirect and direct bandgaps (1.9 eV and 2.16 eV, respectively) in the semiconductor regime. Thermogravimetric analysis suggests that GTUB-4 is thermally stable up to 400 °C. Owing to its high surface area, low bandgap, and high thermal stability, GTUB-4 could find applications as electrodes in supercapacitors.     

The biological effects of 632.8-nm low energy He-Ne laser on peripheral blood mononuclear cells in vitro

The aim of this study was to examine the proliferation of peripheral blood mononuclear cells due to the low energy 632.8-nm He-Ne laser application. The results of previous studies supported the hypothesis that low level laser therapy (LLLT) might have an increasing effect on the proliferation of lymphocytes and production of cytokines. The effect of laser irradiation was investigated by comparing the proliferation of peripheral blood mononuclear cells (PBMC) with a mitogenic stimulator, PHA (phytohemaglutinin) and laser irradiation. PBMCs of control samples, only laser irradiated samples, PHA included samples and both PHA included and laser irradiated samples were quantified and compared. Results of [3H] Thymidine test, 20 s laser irradiated and 40 s laser irradiated samples' proliferation were found statistically higher than control samples. There was no significant difference between control and 60 s laser irradiated samples. PHA also showed its ability to proliferate cells. PHA included samples and both PHA included and laser irradiated samples' proliferation was higher than both control and only laser irradiated samples. Our results showed that He-Ne laser application enhanced the proliferation significantly. Moreover, laser dose was noted as a significant parameter. On the other hand, LLLT by itself was found less effective than PHA.     

An Exponential Growth Learning Trajectory: Students’ Emerging Understanding of Exponential Growth Through Covariation

This article presents an Exponential Growth Learning Trajectory (EGLT), a trajectory identifying and characterizing middle grade students’ initial and developing understanding of exponential growth as a result of an instructional emphasis on covariation. The EGLT explicates students’ thinking and learning over time in relation to a set of tasks and activities developed to engender a view of exponential growth as a relation between two continuously covarying quantities. Developed out of two teaching experiments with early adolescents, the EGLT identifies three major stages of students’ conceptual development: prefunctional reasoning, the covariation view, and the correspondence view. The learning trajectory is presented along with three individual students’ progressions through the trajectory as a way to illustrate the variation present in how the participants made sense of ideas about exponential growth.     

Fully Developed Forced Convection in a Parallel Plate Channel with a Centered Porous Layer

In this study, fully developed heat and fluid flow in a parallel plate channel partially filled with porous layer is analyzed both analytically and numerically. The porous layer is located at the center of the channel and uniform heat flux is applied at the walls. The heat and fluid flow equations for clear fluid and porous regions are separately solved. Continues shear stress and heat flux conditions at the interface are used to determine the interface velocity and temperature. The velocity and temperature profiles in the channel for different values of Darcy number, thermal conductivity ratio, and porous layer thickness are plotted and discussed. The values of Nusselt number and friction factor of a fully clear fluid channel (Nu _cl = 4.12 and fRe _cl = 24) are used to define heat transfer increment ratio (e_th = Nu_p/Nu_cl)({\varepsilon _{\rm th} =Nu_{\rm p}/Nu_{\rm cl})} and pressure drop increment ratio (e_p = fRe_p/fRe_cl )({\varepsilon_{\rm p} =fRe_{\rm p}/fRe_{\rm cl} )} and observe the effects of an inserted porous layer on the increase of heat transfer and pressure drop. The heat transfer and pressure drop increment ratios are used to define an overall performance (e = e_th/e_p)({\varepsilon = \varepsilon_{\rm th}/\varepsilon_{\rm p})} to evaluate overall benefits of an inserted porous layer in a parallel plate channel. The obtained results showed that for a partially porous filled channel, the value of e{\varepsilon} is highly influenced from Darcy number, but it is not affected from thermal conductivity ratio (k _r) when k _r > 2. For a fully porous material filled channel, the value of e{\varepsilon} is considerably affected from thermal conductivity ratio as the porous medium is in contact with the channel walls.     

Novel hexacentered phosphazene compound as selective Fe3+ ions sensor with high quantum yield: Synthesis and application

A novel compound hexa-rhodamine substituted phosphazene (HRP) with six active centers on a cyclotriphosphazene ring was synthesized using the alkyne-azide “click” reaction. The structure of HRP was characterized using spectroscopic techniques. The optical sensor properties of HRP for metal ions were investigated using UV-Vis and Fluorescence spectroscopy. It was determined that HRP is a selective sensor with colorimetric and fluorescent properties for Fe³⁺ ions. Limit of detection (LOD) of HRP was determined as 6.94?×?10^?9 M using fluorescence intensities in the presence of different concentrations of Fe³⁺ ions. It was determined that HRP-Fe³⁺ complex has high quantum yield and excellent photostability.     

Evaluation of Computational Modifications in HPTLC with Gel Analysis Software and Flatbed Scanner for Lipid Separation

JPC – Journal of Planar Chromatography – Modern TLC - High-performance thin-layer chromatography plays an important role in the determination of lipid fractions. However, it requires...