Poly[trans-diaquabis­[μ2-2-(pyridin-3-yl)acetato-κ2 N:O]­zinc]

In the title coordination polymer, [Zn(C7H6NO2)2(H2O)2]n, the ZnII cation is located on an inversion center and is coordinated by four pyridyl­acetate anions and two water mol­ecules in a distorted ZnN2O4 octa­hedral geometry. The pyridine-N and carboxyl­ate-O atoms of the pyridyl­acetate anion connect to two ZnII cations, forming a two-dimensional polymeric complex extending parallel to (212). Inter­molecular O—H⋯O and weak C—H⋯O hydrogen bonding is present in the crystal structure

Carbohydrate metabolism in tomato (Lycopersicon esculentum Mill.) seedlings and yield and fruit quality as affected by low night temperature and subsequent recovery

In order to clarify carbohydrate content and enzymes activities involved in sugar metabolism in tomato seedling leaves and yield and fruit quality under low night temperature and subsequent recovery, tomatoes (Lycopersicon esculentum Mill. cv. Liaoyuanduoli) were grown in different climatic controlledenvironment chambers with day/night temperature regimes of 25/15, 25/9 and 25/6°C for 9 days and then were transferred to 25/15°C chamber for 9 days recovery. The results showed that fructose, glucose and sucrose content under low night temperature and starch content at 9°C were higher than that of the control level; only starch content at 6°C decreased and there was no significantly difference in fructose content between 6 and 9°C. Under low night temperature, sucrose phosphate synthase (SPS) activity in tomato leaves significantly increased. NI activity and SS activity decreased after 3 days treatment and soluble acid invertase (SAI) activity increased after 5 days treated. After 9 days recovery, starch content and SAI activity were difficult to return to the level of the control. After fruits were harvested, the marketable yield and single plant yield decreased in the first cluster fruit of the 6°C treated plants. Enhanced SPS activity and sugar accumulation play important roles in tomato leaves under low night temperature stress.Key words: Low night temperature, Lycopersicon esculentum, sucrose metabolism, enzymes related sugar metabolism, yield and quality

catena-Poly[[silver(I)-μ-N-(3-pyridyl­meth­yl)pyridine-4-carboxamide] nitrate monohydrate]

In the title compound, {[Ag(C12H11N3O)]NO3·H2O}n, the Ag atom is coordinated by two N atoms from the heterocyclic ligand, giving a linear polycationic chain. Two long Ag⋯Onitrate inter­actions [2.667 (3) and 2.840 (3) Å] result in a three-dimensional network. The water mol­ecule consolidates the network structure by forming hydrogen bonds, one to the polycationic chain and one to the nitrate anion

Significance of the lipid profile and endothelium-dependent vasodilatation in the pathogenesis of microvascular angina

Background: To investigate the significance of lipid disorders and endothelial dysfunction in the pathogenesis of microvascular angina. Methods: Levels of plasma lipids, lipoproteins and apolipoproteins were assessed in 21 patients with microvascular angina and 24 healthy subjects as controls. Also, the endothelium-dependent vasodilatation function was determined with high-resolution ultrasound in both groups. Results: Levels of serum total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), apolipoprotein B100 (ApoB100) and lipoprotein(a) [Lp(a)] in microvascular angina group were significantly higher than those in healthy subjects (each p < 0.05). The flow-mediated dilatation (FMD) in brachial arteries in patients with microvascular angina declined significantly as compared with that in control subjects (4.7 &#177; 1.9% vs. 12.8 &#177; 3.7%, p < 0.001). However, no significant difference was observed in response to nitroglycerin between groups (19.7 &#177; 8.1% vs. 21.2 &#177; 6.6%; p > 0.05). Linear correlation analysis revealed a significant negative correlation between the FMD of brachial arteries and the serum levels of LDL-C and Lp(a) in the microvascular angina group (r = -0.5125 and -0.4271, respectively, both p < 0.001). Subsequently, all subjects were pooled and divided into two groups (groups A and B) according to the degree of FMD in brachial arteries (A &#163; 4% and B > 4%). The serum LDL-C level was found to be significantly higher in group A than in group B (4.09 &#177; 0.65 mmol/L vs. 2.59 &#177; 0.49 mmol/L; p < 0.05). Conclusions: Plasma lipid disorders and vascular endothelial dysfunction may play important roles in the development of microvascular angina. The dysfunction of endothelium-dependent vasodilation was mainly associated with anomalies in LDL-C and Lp(a), and myocardial endothelial dysfunction was aggravated by lipid abnormalities in patients with microvascular angina

Vapor-liquid equilibrium properties of binary mixture refrigerants (R1234ZE+R290, R290+R227ea)

The vapor-liquid equilibrium data is an important part of thermophysical properties of a new refrigerant. Theoretical predictions and experimental measurements of vapor-liquid equilibrium data of a new mixed working fluid become to be an urgent need for the researches on alternative refrigerants. The vapor-liquid equilibrium curves of binary mixtures (R1234ze(E)+R290, R290+R227ea) were simulated by COSMO-RS model which are based on quantum chemistry. The simulation results could accord with the experimental data well. It was concluded that COSMO-RS simulation method is feasible to predict the vapor-liquid equilibrium properties of mixed refrigerants