Xiaohai Zhou

Levels of selenium, zinc, copper, and antioxidant enzyme activity in patients with leukemia.

Essential elements, mainly selenium and zinc, were involved in protection against oxidative stress in cells. Oxidation could lead to the formation of free radicals that have been implicated in the pathogenesis of many diseases, including leukemia. Leukemia is a neoplastic disease that is susceptible to antioxidant enzyme and essential elements alterations. This study was undertaken to examine the levels of essential elements, antioxidant enzymes activities, and their relationships with different types of leukemia. Serum selenium, zinc, and copper concentrations, red blood cell glutathione peroxidase (GPx) activities, plasma Cu−Zn superoxide dismutase (Cu−Zn SOD) activities and lipid peroxidation (LPO) levels were determined in 49 patients with different types of leukemia before initial treatment. Serum selenium and zinc concentrations were lower in leukemia patients than those of controls (p<0.01). Serum copper concentration was higher in leukemia patients than that of controls (p<0.01). The activities GPx and Cu−Zn SOD were significantly increased in leukemia patients, especially with acute leukemia (AL), acute lymphoid leukemia (ALL), and acute nonlymphoid leukemia (ANLL) (p<0.05), whereas no difference was found between those of chronic myelogeneous leukemia and the controls. The levels of LPO were normal as controls. Serum selenium concentration was not correlated with GPx, and serum levels of zinc and copper were not related to Cu−Zn SOD. Serum zinc levels had a negative correlation with the absolute peripheral blast cells, whereas serum copper had a positive correlation with the absolute peripheral blast cells. Increased GPx and Cu−Zn SOD activities and normal levels of LPO, which were a protective responses, were an indicator of mild oxidative stress; it mights indicate that the essentials elements alterations in leukemia patients were mostly dependent on tumor activity. Changes of their levels demonstrated that there are low selenium, zinc, and high copper status in leukemia patients. The decrease of plasma zinc and increase of the Cu/Zn ratio could be the index that showed an unfavorable prognosis of acute leukemia.

Electrocatalytic reduction of dioxygen on the surface of glassy carbon electrodes modified with dicobalt diporphyrin complexes

Abstract The electrocatalytic reduction of dioxygen has been studied by cyclic voltammetry at glassy carbon electrodes (GCEs) modified with four different dicobalt diporphyrin complexes in dioxygen-saturated aqueous solutions. The electroreduction of O 2 on modified GCEs is irreversible and diffusion-controlled. Under the catalysis of these metallodiporphyrins, dioxygen reduces to hydrogen peroxide via a two-electron process. The results reveal that the geometric conformation of diporphyrins determines whether dioxygen is reduced by a four-electron process to water or via a two-electron change to hydrogen peroxide.

Synthesis of Cyclic Carbonate From Carbon Dioxide and Epoxide Using Amino Acid Ionic Liquid Under 1 atm Pressure

Herein, we report an effective synthesis of cyclic carbonates by cycloaddition of carbon dioxide to epoxide using a modified amino acid ionic liquid as catalyst under 1 atm pressure. With triethylamine as co-catalyst, the catalytic activity of the l-proline based ionic liquid was greatly enhanced, and up to 97 % isolated yield of cyclic carbonate was achieved at 90°C under atmospheric pressure without organic solvent and metal component.

Synthesis of pillar[n]arenes (n = 5 and 6) with deep eutectic solvent choline chloride 2FeCl3

A novel and distinct method of preparing pillar[5]arene and pillar[6]arene with high selectivity and efficiency has been achieved by condensation of 1,4-dialkoxybenzene and paraformaldehyde with the choline chloride (ChCl)/ferric chloride (FeCl3) deep eutectic solvent in CH2Cl2 at room temperature. Under the optimal conditions, the yield of pillar[5]arene and pillar[6]arene is 35% and 53%, respectively. The reaction mechanism is investigated by room-temperature X-band Electron Spin Resonance (ESR), indicating that a free radical takes part in this cyclization reaction and acts as an intermediate. Our research is the first report about the application of DESs in supramolecular macrocyclic host synthesis.

Synthesis of novel amino-functionalized ionic liquids and their application in carbon dioxide capture

In this study, four novel amino-functionalized ionic liquids, 1-(2-aminoethyl)-1-methylpiperazin-1-ium amino acid salts ([AEMP][A], wherein [A]− = [Gly]−, [Ala]−, [Pro]−, [Leu]−), have been synthesized and characterized, and their physicochemical properties, such as glass transition and thermal decomposition temperatures, were determined. These amino-functionalized ionic liquids, dissolved in solution or supported on SiO2, were applied for carbon dioxide absorption. The results showed that the absorption rate is faster when ionic liquid is supported on silica gel than dissolved in the solution. The absorption capacity reached about 1.5 mol carbon dioxide per mol ionic liquid at ambient pressure, as verified by nuclear magnetic resonance and Fourier transform infrared spectroscopy. Moreover, the amino-functionalized ionic liquid can be recycled under vacuum.

Deep eutectic solvent choline chloride·2CrCl3·6H2O: an efficient catalyst for esterification of formic and acetic acid at room temperature

A highly efficient and selective method for esterification of formic and acetic acid with alcohols has been achieved at room temperature, with the choline chloride (ChCl)/chromium(III) chloride hexahydrate (CrCl3·6H2O) deep eutectic solvent as a catalyst. High yields and good selectivities of organic esters are obtained using DES [ChCl][CrCl3·6H2O]2 with the molar ratio 5 : 1 (carboxylic acids : alcohols) at room temperature in 24 h. The ease of recovery and reusability of DES with high catalytic activity makes this method efficient and practical.

“Liquid-like” type (COO−)2(H2O)10 anion water clusters in three-dimensional supramolecular structure of cucurbit[6]uril

The three-dimensional (3D) supramolecular network structure of the guest 1,1′-(hexane-1,6-diyl)dipyridinium-4-carboxylate inner salt (HBPC) and the host cucurbit[6]uril (CB[6]) is self-assembled through an intricate array of hydrogen-bonding interactions involving the contributions of two-dimensional (2D) infinite network (COO−)2(H2O)10 anion water clusters and (H2O)2 water clusters. These water clusters are notably have the liquid-like water characteristics in the solid and are reversibly dehydrated and rehydrated, while the pseudorotaxane retains its integrity in the process, and is stable up to 390 °C.

Penicillium expansum lipase-coated magnetic Fe3O4–polymer hybrid hollow nanoparticles: a highly recoverable and magnetically separable catalyst for the synthesis of 1,3-dibutylurea

Herein, amino-epoxy supports were innovatively imported onto magnetic nanoparticles (Fe3O4–polymer hybrid nanospheres) for immobilizing enzymes. This new support has a coating layer with dual functional groups (epoxy and amino-epoxy). Consequently, this support has great anionic exchange power and a high number of epoxy groups. The acquired immobilized Penicillium expansum lipase in combination with this heterofunctional support represents a novel class of heterogeneous catalyst towards the synthesis of 1,3-dibutylurea from ethylene carbonate and butylamine, which has not been very commonly catalyzed by enzymes. After optimization of the reaction conditions, the yield of 1,3-dibutylurea was 77% under solvent free conditions at 60 °C. Moreover, after completion of reaction, the catalyst was simply recovered by an external conventional magnet and recycled without significant loss in the catalytic activity (up to ten cycles).

Synthesis and crystal structure of a copper(II) complex of the tripodal tetradentate ligand tris(2-benzimidazolylmethyl)amine

A mononuclear copper complex [Cu(NTB)Cl]Cl·3CH3CH2OH (1) (NTB = tris(2-benzimidazolylmethyl)amine) was synthesized and its structure was determined by single crystal X-ray diffraction. In this complex, copper(II) is five-coordinate with NTB serving as a neutral tetradentate ligand. Three tertiary nitrogen atoms of benzimidazole groups of NTB formed the base of the trigonal bipyramidal geometry. One axial position was occupied by the apical nitrogen atom of NTB and the other was occupied by chloride. The ESR spectrum of complex 1 in ethanol at 101 K was recorded and the well-defined ESR parameters (g ∥ = 2.02, g ⊥  = 2.16 and A ∥  = 109 G) indicated that the Cu(II) has a distorted trigonal-bipyramidal environment, in good agreement with crystal structure determination for complex 1.

Novel chiral ionic liquid (CIL) assisted selectivity enhancement to (L)-proline catalyzed asymmetric aldol reactions

A significant improvement of the chemical yields (up to 88%), stereoselectivity (> 99:1) and enantiomeric excesses (up to 98%) of (L)-proline catalyzed direct asymmetric aldol reaction was found when proline based chiral ionic liquids (CILs) were added as additives. Different ratios of DMSO/H2O as solvent and chiral ionic liquids (CILs) with chiral cations of different chain length were investigated