Effects of Salt Concentration on Formation and Dissociation of β-Lactoglobulin/Pectin Complexes

The formation and dissociation of β-lactoglobulin/pectin complexes at various sodium chloride concentrations (CNaCl) have been studied by turbidimetric titration. An increase of CNaCl up to 0.1 M shifts the critical pHφ1, which designates the formation of β-lactoglobulin/pectin coacervates, to higher pH values, whereas further increase of CNaCl from 0.1 to 0.8 M decreases pHφ1 values. These salt effects can be explained in terms of a salt-enhanced effect at lower salt concentrations or a salt-reduced effect at higher salt concentrations, respectively. On the other hand, the value of pHφ2, which corresponds to the dissociation of β-lactoglobulin/pectin coacervates, tends to have smaller pH values when CNaCl increases from 0.1 to 0.3 M. No observable pHφ2 values are found at CNaCl higher than 0.3 M. The disappearance of pHφ2 is mainly attributed to the strong self-aggregation capability of β-lactoglobulin at higher CNaCl. The aggregation of β-lactoglobulin at high CNaCl is reversible, as suggested by the atomic force microscopy results

Baseline characteristics of cases and controls.

<p>TNM: Tumor, Lymph Node, Metastasis.</p><p>Among 314 patients, 53 have missing TNM stage data.</p

Synthesis, Electrochemistry, Photophysics, and Solvatochromism in New Cyclometalated 6-Phenyl-4-(<i>p</i>-R-phenyl)-2,2′-bipyridyl (R = Me, COOMe, P(O)(OEt)₂) (C^∧N^∧N) Platinum(II) Thiophenolate Chromophores

Three new cyclometalated 6-phenyl-4-(p-R-phenyl)-2,2′-bipyridyl (C∧N∧N) Pt(II) thiophenolate complexes (R = Me (2a), COOMe (2b), and P(O)(OEt)2 (2c)) have been synthesized and studied. The new C∧N∧N ligands L2 (R = COOMe) and L3 (R = P(O)(OEt)2) undergo cyclometalation with a Pt(II) source to give the Pt(II) chloro complexes 1b and 1c, respectively, which are luminescent in fluid solution with λmax ∼ 575 nm, assigned to a metal-to-ligand charge-transfer (3MLCT) emissive state. Reaction of the chloro complexes 1a (R = Me), 1b, and 1c with sodium thiophenolate gives 2a−2c, respectively, in good yields. The novel thiophenolate complexes have two interesting absorption bands in their electronic spectra tentatively assigned to a charge-transfer to C∧N∧N (1CT) (λabs ∼415 nm) transition and a mixed metal/ligand-to-ligand′ charge-transfer (MMLL′CT, λabs ∼ 555 nm) transition, respectively. The MMLL′CT band is solvatochromic with absorption maxima in the range of 496 nm in MeOH to 590 nm in toluene (ε ∼ 4000 dm3 mol−1 cm−1), which correlate well with an empirical charge-transfer-based solvent scale. Excitation of 2a−2c into the MMLL′CT band gives emission maxima around 680 nm in frozen CH2Cl2 solution, and no emission in fluid solution. Ligand L2 and complexes 1a·MeCN, 1b, and 2b·CH2Cl2 have been characterized by single crystal X-ray crystallography. The electrochemical properties of ligands L1 (R = Me) and L2 and complexes 1a−1c and 2a−2c have been examined by cyclic voltammetry and are shown to exhibit reversible and quasi-reversible reductions and irreversible oxidations

Additional file 1 of Association of gallbladder diseases with risk of gastrointestinal polyps

Additional file 1

Energy Transfer of Biexcitons in a Single Semiconductor Nanocrystal

Photoluminescence (PL) decay dynamics of multiexcitons in semiconductor nanocrystals (NCs) are dominated by the nonradiative Auger effect, making it difficult to explore their basic optical processes such as radiative recombination and energy transfer (ET). Here we constructed a single-particle ET system by attaching several acceptor dyes to the surface of a donor NC to study the ET of biexcitons at a single-NC level. By comparing the single-exciton and biexciton PL lifetimes of the same donor NC before and after the acceptor dyes were bleached, their respective ET lifetimes could be reliably extracted without the Auger influence. From statistical measurements on a large number of single ET particles, the average ET rate ratio between biexcitons and single excitons was estimated to be larger than four, and the same scaling rule could be naturally extended to their radiative rates

The genotype distributions of TLR9-1486 T/C in cases and controls.

a<p>Adjusted for age, sex, and <i>H. pylori</i> infection.</p><p>OR, odds ratio; CI, confidence interval.</p

Synthesis, Electrochemistry, Photophysics, and Solvatochromism in New Cyclometalated 6-Phenyl-4-(<i>p</i>-R-phenyl)-2,2′-bipyridyl (R = Me, COOMe, P(O)(OEt)₂) (C^∧N^∧N) Platinum(II) Thiophenolate Chromophores

Three new cyclometalated 6-phenyl-4-(p-R-phenyl)-2,2′-bipyridyl (C∧N∧N) Pt(II) thiophenolate complexes (R = Me (2a), COOMe (2b), and P(O)(OEt)2 (2c)) have been synthesized and studied. The new C∧N∧N ligands L2 (R = COOMe) and L3 (R = P(O)(OEt)2) undergo cyclometalation with a Pt(II) source to give the Pt(II) chloro complexes 1b and 1c, respectively, which are luminescent in fluid solution with λmax ∼ 575 nm, assigned to a metal-to-ligand charge-transfer (3MLCT) emissive state. Reaction of the chloro complexes 1a (R = Me), 1b, and 1c with sodium thiophenolate gives 2a−2c, respectively, in good yields. The novel thiophenolate complexes have two interesting absorption bands in their electronic spectra tentatively assigned to a charge-transfer to C∧N∧N (1CT) (λabs ∼415 nm) transition and a mixed metal/ligand-to-ligand′ charge-transfer (MMLL′CT, λabs ∼ 555 nm) transition, respectively. The MMLL′CT band is solvatochromic with absorption maxima in the range of 496 nm in MeOH to 590 nm in toluene (ε ∼ 4000 dm3 mol−1 cm−1), which correlate well with an empirical charge-transfer-based solvent scale. Excitation of 2a−2c into the MMLL′CT band gives emission maxima around 680 nm in frozen CH2Cl2 solution, and no emission in fluid solution. Ligand L2 and complexes 1a·MeCN, 1b, and 2b·CH2Cl2 have been characterized by single crystal X-ray crystallography. The electrochemical properties of ligands L1 (R = Me) and L2 and complexes 1a−1c and 2a−2c have been examined by cyclic voltammetry and are shown to exhibit reversible and quasi-reversible reductions and irreversible oxidations

Electrical Switching of Optical Gain in Perovskite Semiconductor Nanocrystals

Perovskite semiconductor nanocrystals are promising for optical amplification and laser applications benefiting from efficient optical gain generation. Nevertheless, the pump threshold is limited by more than one exciton per nanocrystal required to generate population inversion in neutral nanocrystals due to the level degeneracy. Here, we show that by charging nanocrystals with current injection, the level degeneracy can be lifted to generate charged exciton gain with markedly low excitation density. On the basis of the scenario, we have demonstrated electrical switching of amplified spontaneous emission in films of CsPbBr3 nanocrystals sandwiched by two electrodes with over 50% threshold reduction owing to charged excitons. Our work provides an effective approach to electrically modulated optical gain in colloidal perovskite nanocrystals for potential applications in advanced laser and information technology

Promotive Effect of the Platinum Moiety on the DNA Cleavage Activity of Copper-Based Artificial Nucleases

Copper-based artificial metallonucleases are likely to satisfy more biomedical requirements if their DNA cleavage efficiency and selectivity could be further improved. In this study, two copper(II) complexes, [CuL1Cl2] (1) and [CuL2Cl2] (2), and two copper(II)−platinum(II) heteronuclear complexes, [CuPtL1(DMSO)Cl4] (3) and [CuPtL2(DMSO)Cl4] (4), were synthesized using two bifunctional ligands, N-[4-(2-pyridylmethoxy)benzyl]-N,N-bis(2-pyridylmethyl)amine (L1) and N-[3-(2-pyridylmethoxy)benzyl]-N,N-bis(2-pyridylmethyl)amine (L2). These complexes have been characterized by elemental analysis, electrospray ionization mass spectrometry, IR spectroscopy, and UV−vis spectroscopy. The DNA binding ability of these complexes follows an order of 1 2 3 4, as revealed by the results of spectroscopy and agarose gel electrophoresis studies. Their cleavage activity toward supercoiled pUC19 plasmid DNA is prominent at micromolar concentration levels in the presence of ascorbic acid. The introduction of a platinum(II) center to the copper(II) complexes induces a significant enhancement in cleavage activity as compared with copper(II) complexes alone. These results show that the presence of a platinum(II) center in copper(II) complexes strengthens both their DNA binding ability and DNA cleavage efficiency

Effects of Polar Group Saturation on Physical Gelation of Amphiphilic Polymer Solutions

Monte Carlo simulation on the basis of the comblike coarse grained nonpolar/polar (NP) model has been carried out to study the polar group saturation effect on physical gelation of amphiphilic polymer solutions. The effects of polar group saturation due to hydrogen bonding or ion bridging on the sol−gel phase diagram, microstructure of aggregates, and chain conformation of amphiphilic polymer solutions under four different solvent conditions to either the nonpolar backbone or the polar side chain in amphiphilic polymer chains have been investigated. It is found that an increase of polar group saturation results in a monotonically decreased critical concentration of gelation point, which can be qualitatively supported by the dynamic rheological measurements on pectin aqueous solutions. Furthermore, various solvent conditions to either the backbone or the side chain have significant impact on both chain conformation and microstructure of aggregates. When the solvent is repulsive to the nonpolar backbone but attractive to the polar side chain, the polymer chains are collapsed, and the gelation follows the mechanism of colloidal packing; at the other solvent conditions, the gelation follows the mechanism of random aggregation