Diverse structures, magnetism and photoluminescence of four transition metal coordination compounds based on the semirigid 4-(pyridin-3-yloxy)-phthalic acid

<div><p>Four transition metal coordination compounds, {[Co(PPDA)(H₂O)₂]}_n (<b>1</b>), {[Ni(HPPDA)₂]}_n (<b>2</b>), {[Cd(PPDA)(H₂O)]∙H₂O}_n (<b>3</b>) and {Zn(HPPDA)₂(H₂O)₄}_n (<b>4</b>), were synthesized by assembling transition metal salts with a semirigid ligand 4-(pyridin-3-yloxy)-phthalic acid (H₂PPDA) under hydrothermal conditions. The compounds have been characterized by elemental analyses, IR spectra, TGA, powder X-ray diffraction (PXRD) and single crystal X-ray crystallography. Compound <b>1</b> exhibits a 3-connected 2-D layered structure, <b>2</b> shows a (3,6)-connected 2-D layered structure, <b>3</b> displays a (3,6)-connected 2-D layered framework based on binuclear units, and <b>4</b> is a mononuclear structure, connected to generate a 3-D supramolecular architecture by hydrogen bonds. Compound <b>2</b> is thermally stable up to 300 °C. The magnetic properties of <b>1</b> and photoluminescent properties of <b>3</b> and <b>4</b> have been explored.</p></div

Visible-Light Mediated Oxidative C–H/N–H Cross-Coupling between Tetrahydrofuran and Azoles Using Air

Tetrahydrofuran is a privileged structural moiety in many important organic compounds. In this work, we have developed a simple and mild catalytic oxidative amination of tetrahydrofuran mediated by visible-light catalysis. The C­(sp3)-H bond of tetrahydrofuran was activated using molecular oxygen as a benign oxidant. Besides, a variety of azoles could be tolerated, providing a green route for N-substituted azoles

Theoretical Studies on the Mechanisms and Dynamics of OH Radical with (CH₃)₃COOH and (CH₃)₂CHOOH

A dual-level direct dynamic method is employed to study the reaction mechanism of hydroxyl radical with (CH₃)₃COOH and (CH₃)₂CHOOH. Eight hydrogen abstraction channels are found for title reactions. The energy paths are optimized at the BH&H-HLYP/6-311G­(d,p) level, and the energy profiles are further refined by interpolated single-point energies method at the CCSD­(T) and QCISD­(T) theories. Rate coefficients for the reactions of the OH with (CH₃)₃COOH/(CH₃)₂CHOOH are computed by the canonical variational transition-state theory with the small-curvature tunneling correction between 200 and 2000 K. The Arrhenius expressions <i>k</i>₁ (T) = 1.49 × 10^–26 T^4.71 exp­(1981.92/T) and <i>k</i>₂ (T) = 1.58 × 10^–20 T^3.32 exp­(210.59/T) over 200–2000 K are obtained

Simple and Sensitive Fluorescent and Electrochemical Trinitrotoluene Sensors Based on Aqueous Carbon Dots

Aqueous N-rich carbon dots (CDs), prepared by the microwave-assisted pyrolysis method, are applied as a dual sensing platform for both the fluorescent and electrochemical detection of 2,4,6-trinitrotoluene (TNT). The fluorescent sensing platform is established on the strong TNT–amino interaction which can quench the photoluminescence of amino functionalized CDs through charge transfer. The resultant linear detection ranges from 10 nM to 1.5 μM with a fast response time of 30 s. Glassy carbon electrode modified with CDs exhibits a fine capability for TNT reduction with the linear range from 5 nM to 30 μM, better than that obtained by the fluorescent method. Moreover, the minimum distinguishable response concentration with respect to these two methods is down to the nanomolar level with a high specificity and sensitivity

Self-Powered Bipolar Electrochromic Electrode Arrays for Direct Displaying Applications

Here we report a self-powered-bipolar-electrochromic-electrode (termed SP-BP-EC-E) array for the displaying applications including catalyst screening, catalytic activity measurement, and enzyme substrate quantification. By replacing the directional (or active) power source with the isotropic chemical energy to drive the bipolar electrochemical reaction, the driving background signal, bipolar electrode (BPE) background signal, uneven reporting signal and the influence of electrolysis which commonly appear in traditional bipolar systems are effectively eliminated from origin. Thus, the reporting signals from the SP-BP-EC-E arrays can be more direct and reliable to reflect the target nature. Such a SP-BP-EC-E platform exhibits a sensitive response toward the fast analysis of commercial Pt black catalyst, NiPdAu hollow nanospheres, glucose dehydrogenase, and glucose. To our knowledge, this test paper-like SP-BP-EC-E is the simplest platform for high-throughput screening to date, which offers a very convenient approach for nonprofessional people to access the complicated screening and fast analysis of the electrocatalysts and biocatalyst activity and quantification of enzymatic substrates

SILAC results showing that eight CCTs members were closely related to the cell’s rigidity response to 10-kPa (Protein Label Light media) and 100-kPa (Protein Label Heavy media) substrates.

<p>TCP1:T-complex protein 1.</p

Chaperonin CCT-Mediated AIB1 Folding Promotes the Growth of ERα-Positive Breast Cancer Cells on Hard Substrates

<div><p>Clinical observations have revealed a strong association between estrogen receptor alpha (ERα)-positive tumors and the development of bone metastases, however, the mechanism underlying this association remains unknown. We cultured MCF-7 (ERα-positive) on different rigidity substrates. Compared with cells grown on more rigid substrates (100 kPa), cells grown on soft substrates (10 kPa) exhibited reduced spreading ability, a lower ratio of cells in the S and G2/M cell cycle phases, and a decreased proliferation rate. Using stable isotope labeling by amino acids (SILAC), we further compared the whole proteome of MCF-7 cells grown on substrates of different rigidity (10 and 100 kPa), and found that the expression of eight members of chaperonin CCT increased by at least 2-fold in the harder substrate. CCT folding activity was increased in the hard substrate compared with the soft substrates. Amplified in breast cancer 1 (AIB1), was identified in CCT immunoprecipitates. CCT folding ability of AIB1 increased on 100-kPa substrate compared with 10- and 30-kPa substrates. Moreover, using mammalian two-hybrid protein-protein interaction assays, we found that the polyglutamine repeat sequence of the AIB1 protein was essential for interaction between CCTζ and AIB1. CCTζ-mediated AIB1 folding affects the cell area spreading, growth rate, and cell cycle. The expressions of the c-myc, cyclin D1, and PgR genes were higher on hard substrates than on soft substrate in both MCF-7 and T47D cells. ERα and AIB1 could up-regulate the mRNA and protein expression levels of the c-myc, cyclin D1, and PgR genes, and that 17 β-estradiol could enhance this effects. Conversely, 4-hydroxytamoxifen, could inhibit these effects. Taken together, our studies demonstrate that some ERα-positive breast cancer cells preferentially grow on more rigid substrates. CCT-mediated AIB1 folding appears to be involved in the rigidity response of breast cancer cells, which provides novel insight into the mechanisms of bone metastasis.</p></div

Effects of the overexpression and/or knock-down of AIB1 and/or CCTζ on the cell proliferation, spreading area, and cell cycle of breast cancer MCF-7 cells grown on silicone substrates with E_Y = 100 kPa (**<i>P</i><0.01).

<p>(<b>A</b>) The mRNA expression levels of AIB1 and CCTζ in control, siAIB1, ovAIB1, siCCTζ, ovCCTζ, siAIB1+ovCCTζ, and siCCTζ+ovAIB1 MCF-7 cell groups were validated by real-time RT-PCR, **<i>P</i><0.01, compared with control cells. (<b>B</b>) The expression of AIB1 in the siAIB1 and ovAIB1 MCF-7 cell was validated by Western Blot. (<b>C</b>) The expression of CCTζ in the siCCTζ and ovCCTζ MCF-7 cells was validated by Western Blot. (<b>D</b>) The expression of AIB1 and CCTζ in the siAIB1+ovCCTζ and siCCTζ+ovAIB1 MCF-7 cells was validated by Western Blot. (<b>E</b>) The spreading area of all Cell types (control, si-AIB1, si-CCTζ, ovAIB1, ovCCTζ, si-AIB1+ovCCTζ, and siCCTζ+ovAIB1) grown on silicone substrates with E_Y = 100 kPa. **<i>P</i><0.01. (<b>F</b>) Growth curves of all cells (control, siAIB1, siCCTζ, ovAIB1, ovCCTζ, siAIB1+ovCCTζ, and siCCTζ+ovAIB1) grown on silicone substrates with E_Y = 100 kPa. **P<0.01. G2/M phase (<b>G</b>), G0/G1 phase (<b>H</b>), and S phase (<b>I</b>) of the cell cycle was assessed in cells (control, si-AIB1, siCCTζ, ovAIB1, ovCCTζ, siAIB1+ovCCTζ, and siCCTζ+ovAIB1) grown on silicone substrates with E_Y = 100 kPa. **P<0.01 compared with si-AIB1.</p

CCT6 (ζ) interacts with AIB1, and stimulates AIB1 refolding via a PFD-independent pathway.

<p>(<b>A</b>) MCF-7 cells were cultured on 100-kPa substrates, and then analyzed by co-immunoprecipitation (co-IP) assay followed by immunoblotting (IB) analysis after 72 h. (<b>B</b>) The expression of AIB1 was then assessed in two breast cancer cell lines (MCF-7 and T47D) grown on different rigidity substrates using Western Blotting. GAPDH was used as a control to confirm equal protein loading. Each lane was loaded with up to 30 µg of protein. (<b>C</b>) The mRNA expression of <i>AIB1</i> in MCF-7 and T47D breast cancer cells grown on different rigidity substrates was assessed using real-time RT-PCR. **P<0.01 compared with 10 and 30 kPa substrates. (<b>D</b>) Altered CCTs folding activity on AIB1 changes in the MCF-7 cells grown on different rigidity substrates (10 kPa, 30 kPa, 100 kPa). (<b>E</b>) MCF-7 cell extracts were assayed before and after CCTζ, ERα, and PFD immunodepletion assayed using [³⁵S]-labeled, and denatured AIB1 (500 ng per lane). The protein concentration of MCF-7 cells was 2.5 mg/mL. PFD immunodepletion did not affect AIB1 refolding. therefore, CCTs folded AIB1 in a PFD-independent pathway. (<b>F</b>) The levels of CCTζ, ERα, and PFD were measured in MCF-7 cell extracts after immunodepletion. (<b>G</b>) Ubiquitinated forms of AIB1 in cells grown on different rigidity substrates with ERα or CCTζ overexpression or knockdown were detected using co-immunoprecipitation (co-IP) with anti-AIB1 antibodies and Western blotting with anti-ubiquitin antibodies.</p

Growth characteristics and morphology of cells grown on different rigidity silicone substrates, E_Y = 10, 30 and 100 kPa (×400). E_Y: the Young’s modulus.

<p>Growth characteristics and morphology of cells grown on different rigidity silicone substrates, E_Y = 10, 30 and 100 kPa (×400). E_Y: the Young’s modulus.</p