[Permeation mechanism of phenolic acid components from traditional Chinese medicine on PES membrane separation process].

To explore the permeation mechanism of micro-molecule medicinal ingredients of water extract of tradition Chinese medicine(TCM) in membrane separation process. With phenolic acid components as the model solute, five phenolic acids with similar molecular weight and structure, namely gallic acid, protocatechuate acid, 4-hydroxybenzoic acid, 3-hydroxybenzoic acid and salicylic acid, were selected in the PES membrane separation experiments. With the relative flux and the transmission rate as indexes, the scanning electron microscopy(SEM) and the electrochemical impedance spectroscopy(EIS) were used to analyze the permeation mechanism of different phenolic acid components. The results showed phenolic acids with similar molecular weight had different permeation behaviors, with decreased relative flux and increased solute permeation with the increase of solute concentration. According to the permeation behavior analyzed by the molecular structure of solute, the transmission rate of phenolic acids increased with the increase of the number of hydroxyl, and the order of substituent positions of phenolic acids based on the permeation rate as follows: para-substituted > meta-substitution > ortho-substitution. Electrochemical impedance spectroscopy reflected the role of charge repulsion in the membrane process; that is to say, the greater the resistance is, the less the solute permeation is. Therefore, the permeation phenomenon of the phenolic acid components in the PES membrane is not only the result of simple sieving mechanisms, but also has the effects of steric hindrance and charge repulsion during the membrane process.

[Study on essential oil separation from Forsythia suspensa oil-bearing water body based on vapor permeation membrane separation technology].

To investigate the feasibility of vapor permeation membrane technology in separating essential oil from oil-water extract by taking the Forsythia suspensa as an example. The polydimethylsiloxane/polyvinylidene fluoride (PDMS/PVDF) composite flat membrane and a polyvinylidene fluoride (PVDF) flat membrane was collected as the membrane material respectively. Two kinds of membrane osmotic liquids were collected by self-made vapor permeation device. The yield of essential oil separated and enriched from two kinds of membrane materials was calculated, and the microscopic changes of membrane materials were analyzed and compared. Meanwhile, gas chromatography-mass spectrometry (GC-MS) was used to compare and analyze the differences in chemical compositions of essential oil between traditional steam distillation, PVDF membrane enriched method and PDMS/PVDF membrane enriched method. The results showed that the yield of essential oil enriched by PVDF membrane was significantly higher than that of PDMS/PVDF membrane, and the GC-MS spectrum showed that the content of main compositions was higher than that of PDMS/PVDF membrane; The GC-MS spectra showed that the components of essential oil enriched by PVDF membrane were basically the same as those obtained by traditional steam distillation. The above results showed that vapor permeation membrane separation technology shall be feasible for the separation of Forsythia essential oil-bearing water body, and PVDF membrane was more suitable for separation and enrichment of Forsythia essential oil than PDMS/PVDF membrane.

[Preliminary study on RC membrane permeability and mechanism of seven traditional Chinese medicine alkaloids such as berberine].

In order to analyze the law of membrane permeation of different alkaloids, seven traditional Chinese medicine alkaloids with different parent nucleus and substituent structures, including berberine, palmatine, sinomenine, matrine, oxymatrine, sophoridine, and tetrandrine, were prepared into the simulated solution with same molar concentration, and the membrane penetrating experiments with membrane RC1K and membrane RC5K were carried out. The dynamic transmittance, the total transmittance and the total adsorption rate of each substance were measured, and the scanning electron microscopy (SEM) images of the membrane surface before and after the membrane experiment were considered to predict and analyze the reason of differences in dynamic transmittance of different alkaloids. The results showed that there were significant differences in the dynamic transmittance of the chemical constituents of different alkaloids during penetrating the two membranes. The contamination degree on the surface of the membrane material was also different. The transmittance of the same compound through the RC5K membrane was larger than that through RC1K membrane. Within a certain range, the smaller the pore size of the membrane, the better the selective screening effect on the chemical constituents of traditional Chinese medicine. All the membrane surfaces were less polluted. The difference in transmittance between different substances on the same membrane showed a positive correlation with the difference in structural complexity, providing an experimental basis for the surface modification design in contamination control of membrane materials. In the design of membrane modified material, the surface properties of the membrane can be improved by grafting different polar groups, thereby changing the adsorption characteristics of the membrane surface. The pore size was designed accordingly to achieve the high transmittance and low pollution of the corresponding compounds.

Brønsted Acid Enabled Nickel-Catalyzed Hydroalkenylation of Aldehydes with Styrene and its Derivatives.

A Brønsted acid enabled nickel-catalyzed hydroalkenylation of aldehydes and styrene derivatives has been developed. The Brønsted acid acts as a proton shuttle to transfer a proton from the alkene to the aldehyde, thereby leading to an economical and byproduct-free coupling. A series of synthetically useful allylic alcohols were obtained through one-step reactions from readily available styrene derivatives and aliphatic aldehydes in up to 88 % yield and with high linear selectivity.

Amide-Ligand-Controlled Highly para-Selective Arylation of Monosubstituted Simple Arenes with Arylboronic Acids.

Pd-catalyzed highly para-selective arylations of monosubstituted simple arenes with arylboronic acids to widely existed biaryls have been developed. Inspired by requisite amide-directing groups in reported selective oxidative couplings, amide ligands, especially DMF, are designed and found to be critical for the selectivity control in current arylations.

[Adsorption characteristics of proteins on membrane surface and effect of protein solution environment on permeation behavior of berberine].

In order to explore the adsorption characteristics of proteins on the membrane surface and the effect of protein solution environment on the permeation behavior of berberine, berberine and proteins were used as the research object to prepare simulated solution. Low field NMR, static adsorption experiment and membrane separation experiment were used to study the interaction between the proteins and ceramic membrane or between the proteins and berberine. The static adsorption capacity of proteins, membrane relative flux, rejection rate of proteins, transmittance rate of berberine and the adsorption rate of proteins and berberine were used as the evaluation index. Meanwhile, the membrane resistance distribution, the particle size distribution and the scanning electron microscope (SEM) were determined to investigate the adsorption characteristics of proteins on ceramic membrane and the effect on membrane separation process of berberine. The results showed that the ceramic membrane could adsorb the proteins and the adsorption model was consistent with Langmuir adsorption model. In simulating the membrane separation process, proteins were the main factor to cause membrane fouling. However, when the concentration of proteins was 1 g•L⁻¹, the proteins had no significant effect on membrane separation process of berberine.

Ligand-Accelerated Direct C-H Arylation of BINOL: A Rapid One-Step Synthesis of Racemic 3,3'-Diaryl BINOLs.

An ortho-selective rhodium-catalyzed direct C-H arylation of 1,1'-bi-2-naphthol (BINOL), to deliver the widely used but not easily available 3,3'-diaryl BINOL, has been developed. This highly efficient one-step synthetic approach is the shortest route to date and is greatly facilitated by the newly developed ligand system comprising tBu2 PCl, Ph2 -cod, and Cy3 P⋅HBF4 . In addition, the same procedure can facilitate the challenging syntheses of 3-bulkyaryl BINOLs in good to excellent yields.

Substrate-controlled [4+1] and [3+2] annulations of ninhydrin-derived Morita-Baylis-Hillman carbonates to access polysubstituted furans and cyclopentenes.

The effective and mild [4+1] annulation of ninhydrin-derived MBH carbonates with α,ß-unsaturated ketones has been developed, providing a wide range of multisubstituted furans in high yields (up to 90%) with excellent ß-regioselectivities. In contrast, the polysubstituted cyclopentenes bearing dispiro-bisindanedione motifs were obtained via classical [3+2] annulations by employing ninhydrin-derived MBH carbonates with 2-arylidene-1,3-indandiones under the same catalytic conditions. Furthermore, the structures of two kinds of cycloadducts were straightforwardly confirmed through X-ray diffraction analysis.

Comparative analysis of the performance of hepatobiliary agents in depicting MRI features of microvascular infiltration in hepatocellular carcinoma.

OBJECTIVE: To compare the ability to depict MRI features of hepatobiliary agents in microvascular infiltration (MVI) of hepatocellular carcinoma (HCC) during different stages of dynamic enhancement MRI. MATERIALS AND METHODS: A retrospective study included 111 HCC lesions scanned with either Gd-EOB-DTPA or Gd-BOPTA. All cases underwent multiphase dynamic contrast-enhanced scanning before surgery, including arterial phase (AP), portal venous phase (PVP), transitional phase (TP), delayed phase (DP), and hepatobiliary phase (HBP). Two abdominal radiologists independently evaluated MRI features of MVI in HCC, such as peritumoral hyperenhancement, incomplete capsule, non-smooth tumor margins, and peritumoral hypointensity. Finally, the results were reviewed by the third senior abdominal radiologist. Chi-square (χ2) Inspection for comparison between groups. P < 0.05 is considered statistically significant. Receiver operating characteristic (ROC) curve was used to evaluate correlation with pathology, and the area under the curve (AUC) and 95% confidence interval (95% CI) were calculated. RESULTS: Among the four MVI evaluation signs, Gd-BOPTA showed significant differences in displaying two signs in the HBP (P < 0.05:0.000, 0.000), while Gd-EOB-DTPA exhibited significant differences in displaying all four signs (P < 0.05:0.005, 0.006, 0.000, 0.002). The results of the evaluations of the two contrast agents in the DP phase with incomplete capsulation showed the highest correlation with pathology (AUC: 0.843, 0.761). By combining the four MRI features, Gd-BOPTA and Gd-EOB-DTPA have correlated significantly with pathology, and Gd-BOPTA is better (AUC: 0.9312vs0.8712). CONCLUSION: The four features of hepatobiliary agent dynamic enhancement MRI demonstrate a good correlation with histopathological findings in the evaluation of MVI in HCC, and have certain clinical significance.

Comparison of the Ability of Gadobenate Dimeglumine and Gadolinium Ethoxybenzyl Dimeglumine to Display the major Features for Noninvasively Diagnosing Hepatocellular Carcinoma According to the LI-RADS 2018v.

OBJECTIVE: To compare the ability of gadolinium ethoxybenzyl dimeglumine (Gd-EOB-DTPA) and gadobenate dimeglumine (Gd-BOPTA) to display the 3 major features recommended by the Liver Imaging Reporting and Data System (LI-RADS 2018v) for diagnosing hepatocellular carcinoma (HCC). MATERIALS AND METHODS: In this retrospective study, we included 98 HCC lesions that were scanned with either Gd-EOB-DTPA-MR or Gd-BOPTA-M.For each lesion, we collected multiple variables, including size and enhancement pattern in the arterial phase (AP), portal venous phase (PVP), transitional phase (TP), delayed phase (DP), and hepatobiliary phase (HBP). The lesion-to-liver contrast (LLC) was measured and calculated for each phase and then compared between the 2 contrast agents. A P value < .05 was considered statistically significant. The display efficiency of the LLC between Gd-BOPTA and Gd-EOB-DTPA for HCC features was evaluated by receiver operating characteristic (ROC) curve analysis. RESULTS: Between Gd-BOPTA and Gd-EOB-DTPA, significant differences were observed regarding the display efficiency for capsule enhancement and the LLC in the AP/PVP/DP (P < .05), but there was no significant difference regarding the LLC in the TP/HBP. Both Gd-BOPTA and Gd-EOB-DTPA had good display efficiency in each phase (AUCmin > 0.750). When conducting a total evaluation of the combined data across the 5 phases, the display efficiency was excellent (AUC > 0.950). CONCLUSION: Gd-BOPTA and Gd-EOB-DTPA are liver-specific contrast agents widely used in clinical practice. They have their own characteristics in displaying the 3 main signs of HCC. For accurate noninvasive diagnosis, the choice of agent should be made according to the specific situation.

Ni-catalyzed hydroaminoalkylation of alkynes with amines.

Allylic amines are versatile building blocks in organic synthesis and exist in bioactive compounds, but their synthesis via hydroaminoalkylation of alkynes with amines has been a formidable challenge. Here, we report a late transition metal Ni-catalyzed hydroaminoalkylation of alkynes with N-sulfonyl amines, providing a series of allylic amines in up to 94% yield. Double ligands of N-heterocyclic carbene (IPr) and tricyclohexylphosphine (PCy3) effectively promote the reaction.

Variable scan rate cyclic voltammetry and theoretical studies on tocopherol (vitamin E) model compounds.

Variable scan rate (0.1-500 V s(-1)) cyclic voltammetry experiments were performed on a series of model tocopherol (vitamin E) compounds with differing degrees of methyl substitution around the aromatic (phenolic) ring. alpha-Tocopherol, with a fully methylated aromatic ring, produced stable phenoxonium cations upon oxidation in CH3CN, and was modeled via an ECE mechanism (where "E" represents an electron transfer and "C" a chemical step). Compounds with less methyl substitution around the aromatic ring were more reactive following oxidation, and formed additional oxidation products (hemiketals and p-quinones), and were modeled according to a more complicated ECECC mechanism. The equilibrium and rate constants associated with the chemical steps were estimated by digital simulations of the variable scan rate data over a range of temperatures ( T = 253-313 K) in acetonitrile containing 0.5 M Bu4NPF6 as the supporting electrolyte. The relative lifetimes of the phenoxonium cations of tocol and the tocopherols were compared with theoretical results obtained from molecular orbital calculations.

Long-lived radical cations as model compounds for the reactive one-electron oxidation product of vitamin E.

Heterocyclic compounds with structures similar to vitamin E, but without the hydroxyl hydrogen atom, were synthesized and their electrochemical behavior examined in acetonitrile solutions and as solids in aqueous solutions of varying pH by attaching the compounds to the surface of a glassy carbon electrode. Compound 1, containing a fully methylated aromatic ring was found to be the most long-lived following one-electron oxidation, with its radical cation (1+*) surviving in acidic aqueous solutions and able to be isolated as a salt, 1+*(SbF6-), when reacted with NOSbF6 in CH3CN. Electrochemical, UV-vis and FTIR experiments on 1+*, in addition to the results from theoretical calculations, indicated that the electrochemical, electronic and structural properties of 1+* are very similar to those of the radical cation of vitamin E.

Voltammetrically controlled electron transfer reactions from alkanethiol modified gold electrode surfaces to low molecular weight molecules deposited within lipid (lecithin) bilayers.

A procedure was developed for initiating electron transfer from a gold electrode to a low molecular weight electron acceptor present inside supported lipid (lecithin) bilayers, followed by further electron transfer to an electron acceptor present in an aqueous solution. The electron acceptors present in the lecithin bilayers and aqueous phase were 7,7,8,8-tetracyanoquinodimethane (TCNQ) and [Fe(III)(CN)(6)](3-), respectively. A polished planar gold disk electrode was first coated via self-assembly procedures with an alkanethiol monolayer. A phospholipid layer consisting of multiple bilayers of lecithin containing TCNQ was subsequently deposited onto the alkanethiol monolayer. The Au/alkanethiol/lecithin-TCNQ electrode was placed in an aqueous solution containing various amounts of [Fe(III)(CN)(6)](3-) and [Fe(II)(CN)(6)](4-), with 0.5 M KCl as the supporting electrolyte. In the absence of TCNQ inside the alkanethiol/lecithin layers, only a small background current was observed. When TCNQ was included in the alkanethiol/lecithin layers, the voltammetry showed features typical of a catalytic process, due to the TCNQ being reduced to TCNQ(-*) within the lecithin bilayers and then undergoing oxidation back to TCNQ via interaction with [Fe(III)(CN)(6)](3-) at the lecithin-aqueous solution interface. The procedures for preparing the alkanethiol/lecithin-TCNQ coatings were optimized in order to obtain the most reproducible voltammetric response. Experiments were also performed using tetrathiafulvalene (TTF) as an electron donor in the lipid bilayer phase.