Dry fractionation efficiency of milk fats from different sources and the characteristics of their fractions in chemical composition, thermal property, and crystal morphology.

The physicochemical properties of anhydrous milk fats (AMF) often change according to different regions and seasons, inevitably affecting dry fractionation. This study analyzed the differences in the fraction yields and physicochemical characteristics of four AMFs from different sources. The results showed that single-stage dry fractionation conducted at 25 °C easily separated AMFs into liquid fractions (L25) and solid fractions (S25) via pressure filtration, both producing satisfactory yields. Moreover, all L25s exhibited few crystals with good fluidity at 25 °C, while S25s presented as semi-solids supported by ß crystal networks with a certain hardness and plasticity. However, four AMFs displayed fractionation efficiency variation, while the thermal differences among them showed no obvious correlation with those among their fractions. Generally, more trisaturated triglycerides with 48 to 54 carbon atoms in the AMF increased the S25 yield and decreased the slip melting points (SMP) of both fractions.

Effects of pH and Ionic Strength in Calcium on the Stability and Aeration Characteristics of Dairy Emulsion.

The effects of different pH levels and ionic strength in calcium on the stability and aeration characteristics of dairy emulsions were investigated in this study. The results revealed that the stability and aeration characteristics of the emulsion were enhanced as the pH value increased from 6.5 to 7.0 and were optimal within the pH of 6.8~7.0, while the concentration of free calcium ions (Ca2+) was 2.94~3.22 mM. With the pH subsequently fixed at 6.8 and 7.0, when the addition of CaCl2 was increased to 2.00 mM (free Ca2+ strength > 4.11 mM), stability and aeration characteristics reduced significantly, including the flocculation of fat globules, an increase in particle size, and a decrease in the zeta potential and viscosity of the O/W emulsion, all leading to an increase in interfacial protein mass and decreased overrun and foam firmness. Overall, the results indicated that pH changes and CaCl2 addition significantly influenced the stability and aeration characteristics of dairy emulsions, by influencing free Ca2+ strength, which is an important factor in determining the quality of dairy emulsions.

Thickening mechanism of recombined dairy cream stored at 4 °C: Changes in the composition and structure of milk protein under different sterilization intensities.

This work elucidates the mechanism involved in the effect of varying sterilization intensities on RDC thickening via comparative analysis of the changes in the composition and structure of RDC interfacial protein after storage at 4 °C and at 25 °C. The results showed that pasteurized RDCs (75 °C for 16 s, 90 °C for 5 min) and high-temperature sterilized RDCs (105 °C for 3 min, 115 °C for 7 min and 121 °C for 7 min) did not thicken during storage at 25 °C, and had lower viscosities and higher Ca2+ concentrations than those stored at 4 °C. Whey protein (WP) aggregates were found to have been adsorbed at the interface of high-temperature treated RDCs stored at 4 °C, leading to the aggregation of fat globules and, consequently, reversible thickening. However, high-temperature sterilized RDCs underwent into irreversible thickening at 10 d, 7 d and 3 d. This phenomenon was attributed to the large amount of heat-induced whey protein and κ-casein complex that was absorbed on the oil-water interface, with Ca2+ bonded to form bridging flocculation, which altered the secondary structure of the interfacial protein to one with increased ß-sheet content and decreased random coil content.

Erratum: "Baicalin prevents pulmonary arterial remodeling in vivo via the AKT/ERK/NF-κB signaling pathways".

[This corrects the article DOI: 10.1177/2045894019878599.].

Effect of Different Polymerization Degrees and Fatty Acids of Polyglycerol Esters on the Physical Properties and Whippability of Recombined Dairy Cream.

Polyglycerol esters (PGEs) are used as emulsifiers in recombined dairy cream (RDC) to improve product quality. In this study, the effects of four PGEs with different polymerization degrees and esterification on the particle size, viscosity, zeta potential, and microrheology of RDC emulsions were investigated, and the whipping time, overrun, serum loss, and firmness of the RDC emulsions were recorded. The results show that the addition of the PGEs reduced the particle size (from 2.75 µm to 1.48-1.73 µm) and increased the viscosity (from 41.92 cP to 73.50-100 cP) and stability (from 0.354 to 0.105-0.128), which were related to the change in interfacial properties and the weakening of Brownian motion, but there were differences in the effect on the whipping behavior of the RDCs. Although the addition of 0.9% triglyceride monolaurate gave the emulsion the best stability, the RDC had a longer whipping time (318 s) and a lower overrun (116.6%). Comparatively, the 0.7-0.9% concentrations of PGE55 and tripolycerol monostearate (TMS) provided RDC with good stability and aeration characteristics, allowing inflation within 100 s and expansion rates of up to 218.24% and 186.88%, respectively. In addition, the higher degree of polymerization of polyglyceryl-10 monstearate (PMS) did not work well at any concentration. These results contribute to understanding the mechanism of action of PGEs and improving the quality of RDC.

Baicalin prevents pulmonary arterial remodeling in vivo via the AKT/ERK/NF-κB signaling pathways.

Pulmonary arterial hypertension is a rapidly progressive and often fatal disease. As the pathogenesis of pulmonary arterial hypertension remains unclear, there is currently no good drug for pulmonary arterial hypertension and new therapy is desperately needed. This study investigated the effects and mechanism of baicalin on vascular remodeling in rats with pulmonary arterial hypertension. A rat pulmonary arterial hypertension model was constructed using intraperitoneal injection of monocrotaline, and different doses of baicalin were used to treat these rats. The mean pulmonary arterial pressure (mPAP) and right ventricular systolic pressure (RVSP) were measured with a right heart catheter. Moreover, the hearts were dissected to determine the right ventricular hypertrophy index (RVHI). The lung tissues were stained with H&E and Masson's staining to estimate the pulmonary vascular remodeling and collagen fibrosis, and the expression of proteins in the AKT, ERK, and NF-κB p65 phosphorylation (p-AKT, p-ERK, p-p65) was examined by Western blot analysis. We found that compared with untreated pulmonary arterial hypertension rats, baicalin ameliorated pulmonary vascular remodeling and cardiorespiratory injury, inhibited p-p65 and p-ERK expression, and promoted p-AKT and p-eNOS expression. In conclusion, baicalin interfered with pulmonary vascular remodeling and pulmonary arterial hypertension development in rats through the AKT/eNOS, ERK and NF-κB signaling pathways.

ITE promotes hypoxia-induced transdifferentiation of human pulmonary arterial endothelial cells possibly by activating transforming growth factor-ß/Smads and MAPK/ERK pathways.

This study aimed to investigate the transdifferentiation of human pulmonary arterial endothelial cells (HPAECs) into smooth muscle like (SM-like) cells under hypoxic conditions and reveal the role of endogenous small molecular compound 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylicacid methyl ester (ITE) in this process. HPAECs were treated by hypoxia and hypoxia + ITE with different durations. The endothelial markers (CD31 and VE-cad) and smooth muscle markers (α-SMA, SM22α, and OPN) were investigated by immunofluorescence double staining, and their expressions, along with the differentiation regulators transforming growth factor-ß (TGF-ß) ligands and downstream signals including TGF-ß1, bone morphogenetic protein (BMP2), BMP9, Samd2/3, ERK, and p38 MAPK, were determined by Western blot analysis. The viability and proliferation of HPAECs were detected by Cell Counting Kit-8 (CCK-8) method and bromodeoxyuridine (BrdU) assays. As a result, hypoxia induced HPAECs transdifferentiation from paving-stone-like into polygonal or spindle cells, whose number increased greatly after additional ITE stimulation for 7 days. Compared with the normoxic HPAECs, the expression of endothelial markers reduced and smooth muscle markers were enhanced with the extension of hypoxia + ITE treatment, and meanwhile the cell viability increased significantly. Hypoxia could promote expression of TGF-ß1 protein rather than BMP2 and BMP9, and regulate phosphorylation levels of Samd2/3, ERK and p38 MAPK in different manners. In conclusion, ITE can promote the hypoxia-induced transdifferentiation of HPAECs into SM-like cells via TGF-ß/Smads and MAPK/ERK pathways.

Expression and analyses of the HIF-1 pathway in the lungs of humans with pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is characterized by endothelial dysfunction and structural remodeling of the pulmonary vasculature, mediated initially by reduced oxygen availability in the lungs. Hypoxia inducible factor (HIF), consisting of the functional subunit, HIF­1α, and the constitutively expressed HIF­1ß, is involved in the pathological processes associated with hypoxia. In the current study, the sequences of cDNAs and amino acids of HIF were characterized and analyzed using online bioinformatics tools. To further evaluate whether HIF accounts for the occurrence of PAH, the present study determine the expression and phosphorylation levels of HIF and its associated pathways, including extracellular signal­regulated kinase (Erk)1/2 and phosphoinositide 3­kinase (PI3K)/Akt, in the lungs of patients with PAH by reverse transcription­quantitative polymerase chain reaction and western blotting. The mRNA expression levels of PI3K, Erk2, and HIF­1α in the patients with PAH were significantly higher, compared with those in the control group, by 3.6­fold (P<0.01), 4.06­fold and 2.64­fold (P<0.05), respectively. No significant differences were found in the mRNA and protein levels of Akt between the two groups (P>0.05). The protein levels of phosphorylated (p­)Akt, Erk1/2, p­Erk1/2, HIF­1α and HIF­1ß were significantly increased by 5.89­, 0.5­, 0.59­, 1.46­ and 0.92­fold, respectively, in the patients with PAH, compared with those in the controls group (P<0.01 for p­Akt, Erk1/2; P<0.05 for p­Erk1/2, HIF­1α and HIF­1ß). These findings suggested that the mitogen­activated protein kinase and PI3K/Akt signaling pathways, and HIF­1 may perform a specific function in the pathogenesis of PAH.

Baicalin inhibits inflammation and attenuates myocardial ischaemic injury by aryl hydrocarbon receptor.

OBJECTIVES: Recent evidence indicates that suppressing inflammation by specific drug target and treatment measures contributes to attenuate ischaemic injury and the related heart diseases. This study aimed to investigate the potential effect of baicalin on myocardial ischaemic injury through inhibition of inflammation by inactivating the aryl hydrocarbon receptor (AhR). METHODS: The mouse model with myocardial ischaemic injury was prepared by the left anterior descending coronary artery-amputation and then treated using baicalin. After observing the expression of AhR by immunohistochemical staining, the AhR and inflammatory mediators in circulation and myocardial tissues, including high-sensitive C-reactive protein (hsCRP), interleukin (IL)-1ß and IL-6, were detected based on enzyme-linked immunosorbent assay, real-time polymerase chain reaction and Western blot methods. KEY FINDINGS: The results showed that (1) substantial expression of AhR was observed in myocardial tissues; (2) ischaemic injury caused myocardial necrosis and remodelling, and stimulated hsCRP, IL-1ß and IL-6 by activation of AhR; and (3) baicalin alleviated the myocardial injury and inflammatory response by inhibiting the expression of AhR. CONCLUSION: Our findings extend the list of AhR ligands beyond exogenous toxins and endogenous molecules to cardiac immunological factors, and moreover it could be considered potential drug targets due to its pathological modulatory properties, while baicalin demonstrated promise as a novel vehicle for ischaemic heart disease.

Substituent effect on the acid-promoted hydrolysis of 2-aryloxazolin-5-one: normal vs reverse.

Computational investigations on the acid-promoted hydrolysis of 2-aryl-4,4-dimethyloxazolin-5-one (AMO) and its seven para- and meta-substituted derivatives (with electron-donating groups R = OH, OCH(3), CH(3) and electron-withdrawing groups R = Cl, m-Cl, CF(3), NO(2)) were presented by the density functional theory (B3LYP) method. Two types of reaction mechanism, N-path and O-path, are taken into account, in which the attacks by water molecules at the C2 and C5 are accelerated after the protonation on N3 and carbonyl oxygen atoms, respectively. Our computational results clearly manifest that the hydrolysis of AMOs has an obvious substituent effect at the para and meta positions of the benzene ring by correlating the barrier heights with the Hammett constants of substituents. Furthermore, the N-path shows a normal substituent effect, while the favorable O-path shows a reverse substituent effect. The observed reverse substituent effect in experiment actually springs from the reverse substituent effect of the O-path, not the N-path. The substituent effect of the N-path and O-path can be explained by the electrostatic potential at nuclei (EPN) values and Fukui function, respectively. Our theoretical data provided will allow for a better understanding of the acid-promoted hydrolysis mechanism and the observed reverse substituent effect of the AMOs, in nice agreement with the available experimental conclusion.

Theoretical study of the acid-promoted hydrolysis of oxazolin-5-one: a microhydration model.

The acid-promoted hydrolysis of 2,4,4-trimethyloxazolin-5-one (TMO) is studied employing the density functional theory (B3LYP) method in conjunction with the 6-31++G(d,p) basis set. Two types of reaction mechanism, N-protonated and O-protonated, are considered, involving protonation at the nitrogen and carbonyl oxygen of TMO to activate the C2 and C5 atoms, respectively, in favor of attack by water molecules. In the N-protonated pathway, the nucleophilic water molecule attacks the activated C2 atom, with a proton transfer from the water molecule to the oxygen atom attached to C2 and the fission of the C2-O bond, leading to a cis ring-opening product (N-acyl-alpha-amino isobutyric acid). While, in the O-protonated pathway, the nucleophilic water molecule attacks the activated carbonyl C5 atom, accompanied by a proton transfer from the water molecule toward the nitrogen atom of oxazole ring and the cleavage of C5-O bond; as a result, a corresponding trans product is generated. The water-assisted hydrolysis reactions are also examined together. A local microhydration model, in which an extra water molecule was added to obtain a continuous H-bond network around the reaction centers, was adopted to mimic the system for the two types of reaction processes. In addition, bulk solvent effect is introduced by use of the conductor-like polarizable continuum model (CPCM). Our computational results in kinetics and thermodynamics clearly manifest that the O-protonated pathway with the nucleophilic attack at the carbonyl C5 atom is more favorable than the N-protonated one, in nice agreement with the available experimental conclusion.

DFT Study and Monte Carlo Simulation on the Aminolysis of XC(O)OCH3 (X = NH2, H, and CF3) with Monomeric and Dimeric Ammonias.

The aminolysis of substituted methylformates (XC(O)OCH3, X = NH2, H, and CF3) in the gas phase and acetonitrile are investigated by the density functional theory B3LYP/6-311+G(d,p) method and Monte Carlo (MC) simulation with free energy perturbation (FEP) techniques. The direct and the ammonia-assisted aminolysis processes are considered, involving the monomeric and dimeric ammonia molecules, respectively. In each case, two different pathways, the concerted and stepwise, are explored. The calculated results show that, for the direct aminolysis, the activation barrier of the concerted path is lower than that of the rate-controlling step of the stepwise process for all three reaction systems. In contrast, for the ammonia-assisted mechanism, the stepwise process is more favorable than the concerted pathway. The substituent effects at the carboxyl C atom of methylformate are discussed. This aminolysis of substituted methylformates is more favored for X = CF3 than for X = H and NH2 in the gas phase for both the direct and the ammonia-assisted processes. Solvent effects of CH3CN on the reaction of HC(O)OCH3 + nNH3 (n = 1, 2) are determined by Monte Carlo simulation. The potential energy profiles along the minimum energy paths in the gas phase and in acetonitrile are obtained. It is shown that CH3CN lowers the energy barriers of all reactions.

A computational study on the mechanism for the chemical fixation of nitric oxide leading to 1,2,3-oxadiazole 3-oxide.

The chemical fixation of nitric oxide (NO) reacting with alkynyllithium to produce 5-methyl-3-oxide-1,2,3-oxadiazole has been investigated by using ab initio (U)MP2 and DFT/(U)B3LYP methods. The solvent effect was assessed using the combination of microsolvation model with explicit THF ligands on lithium and continuum solvent model based on the SCRF/CPCM method at the (U)B3LYP/6-31G* level. Our results reveal that the overall reaction is stepwise and considered to include two processes. In process 1, the nitrogen atom in nitric oxide at first attacks the C(1) atom in alkynyllithium to afford the intermediate 5. In process 2, after another nitric oxide reacted with the intermediate 5 to produce 8a, we found that two pathways are involved. For path 1, the O(2) atom at first attacks the C(2) atom to form a five-membered ring geometry, and then lithium can rotate around the N(1)-O(1) bond, leading to the product 5-methyl-3-oxide-1,2,3-oxadiazole followed addition of water. However, for path 2, lithium atom rotates first around the N(1)-O(1) bond, and then the product 5-methyl-3-oxide-1,2,3-oxadiazole is also generated by addition of water. Our calculations indicate that path 1 is more favorable than path 2 in the gas phase, while both of them exist possibly in THF solvent. The overall reaction is exothermic.

Theoretical studies for structures and energetics of Rgn-N2O (Rg=He, Ne, Ar) clusters.

Minimum-energy structures of the Rg(2)-N(2)O (Rg=He, Ne, Ar) clusters have been determined with ab initio MP2 optimization, whereas the minimum-energy structures of the Rg(n)-N(2)O clusters with n = 3-7 have been obtained with the pairwise additive potentials. Interaction energies and nonadditive three-body effects of the Rg(2)-N(2)O ternary complex have been calculated using supermolecule method at MP4 and CCSD(T) levels. It was found from the calculations that there are two minima corresponding to one distorted tetrahedral structure and one planar structure for the ternary complex. The nonadditive three-body effects were found to be small for Rg(2)-N(2)O complexes. Our calculations also indicated that, for He(n)-N(2)O and Ne(n)-N(2)O clusters, the first six He and Ne atoms form the first solvation ring around the middle nitrogen of the N(2)O monomer, while for Ar(n)-N(2)O, the first five Ar atoms form the first solvation ring.

Quantum calculation of highly excited vibrational energy levels of CS2(X) on a new empirical potential energy surface and semiclassical analysis of 1:2 Fermi resonance.

We report a refined potential energy function for the ground electronic state of CS2 based on a least-squares fitting to several low-lying experimental vibrational frequencies. Energy levels up to 20,000 cm(-1) have been obtained on this empirical potential using the Lanczos algorithm and potential optimized discrete variable representation. Among them, 329 levels below 10,000 cm(-1) are assigned with approximate normal mode quantum numbers (n1, n(0)2, n3), based on expectation values of one-dimensional (1D) reference Hamiltonians. An effective Hamiltonian is extracted from these assigned levels. The agreement with experimental data, including those of several isotopically substituted species, is excellent. In addition, some Fermi and anharmonic resonances are analyzed. The nearest neighbor level spacing and delta3 distributions indicated that the vibrational spectrum of CS2 is largely regular in the energy range up to 20,000 cm(-1). Semiclassical phase space analysis, including bifurcation analysis of the spectroscopic Hamiltonian, is used to interpret subtle anomalies signaled by expectation values used in normal mode assignments. The meaning of Fermi resonance is clarified by contrasting the semiclassical analysis of CS2 and CO2.