Vasorelaxing Activity of Ulmus davidiana Ethanol Extracts in Rats: Activation of Endothelial Nitric Oxide Synthase

Ulmus davidiana var. japonica Rehder (Urticales: Ulmaceae) (UD) is a tree widespread in northeast Asia. It is traditionally used for anticancer and anti-inflammatory therapy. The present study investigated the effect of an ethanol extract of UD on vascular tension and its underlying mechanism in rats. The dried root bark of UD was ground and extracted with 80% ethanol. The prepared UD extract was used in further analysis. The effect of UD on the cell viability, vasoreactivity and hemodynamics were investigated using propidium iodide staining in cultured cells, isometric tension recording and blood pressure analysis, respectively. Low dose of UD (10~100µg/ml) did not affect endothelial cell viability, but high dose of UD reduced cell viability. UD induced vasorelaxation in the range of 0.1~10µg/ml with an ED50 value of 2µg/ml. UD-induced vasorelaxation was completely abolished by removal of the endothelium or by pre-treatment with L-NAME, an inhibitor of nitric oxide synthase. UD inhibited calcium influx induced by phenylephrine and high K+ and also completely abolished the effect of L-NAME. Intravenous injection of UD extracts (10~100 mg/kg) decreased arterial and ventricular pressure in a dose-dependent manner. Moreover, UD extracts reduced the ventricular contractility (+dP/dt) in anesthetized rats. However, UD-induced hypotensive actions were minimized in L-NAME-treated rats. Taken together, out results showed that UD induced vasorelaxation and has antihypertensive properties, which may be due the activation of nitric oxide synthase in endothelium

A Case of Campomelic Dysplasia without Sex Reversal

Campomelic dysplasia (CD; OMIM #114290), a rare form of congenital short-limbed dwarfism, is due to mutations in SOX9, a member of the SOX (SRY-related HMG box) gene family. Multiparous mother at 38 weeks' gestation delivered a 3,272 g baby boy with characteristic phenotypes including bowing of the lower limbs, a narrow thoracic cage, 11 pairs of ribs, hypoplastic scapulae, macrocephaly, flattened supraorbital ridges and nasal bridge, cleft palate, and micrognathia. He underwent a tracheostomy at the age of three months for severe laryngomalacia after a number of repeated hospitalizations due to respiratory problems and died at the age of four months from progressive respiratory failure. He was diagnosed as having CD based on a novel frameshift mutation (p.Gln458ArgfsX12) in the SOX9 gene, the mutation which has not yet been reported in Korea

Facile Fabrication and Characterization of Improved Proton Conducting Sulfonated Poly(Arylene Biphenylether Sulfone) Blocks Containing Fluorinated Hydrophobic Units for Proton Exchange Membrane Fuel Cell Applications

Sulfonated poly(arylene biphenylether sulfone)-poly(arylene ether) (SPABES-PAE) block copolymers by controlling the molar ratio of SPABES and PAE oligomers were successfully synthesized, and the performances of SPABES-PAE (1:2, 1:1, and 2:1) membranes were compared with Nafion 212. The prepared membranes including fluorinated hydrophobic units were stable against heat, nucleophile attack, and physio-chemical durability during the tests. Moreover, the polymers exhibited better solubility in a variety of solvents. The chemical structure of SPABES-PAEs was investigated by 1H nuclear magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FT-IR), and gel permeation chromatography (GPC). The membrane of SPABES-PAEs was fabricated by the solution casting method, and the membranes were very flexible and transparent with a thickness of 70⁻90 μm. The morphology of the membranes was observed using atomic force microscope and the ionic domain size was proved by small angle X-ray scattering (SAXS) measurement. The incorporation of polymers including fluorinated units allowed the membranes to provide unprecedented oxidative and dimensional stabilities, as verified from the results of ex situ durability tests and water uptake capacity, respectively. By the collective efforts, we observed an enhanced water retention capacity, reasonable dimensional stability and high proton conductivity, and the peak power density of the SPABES-PAE (2:1) was 333.29 mW·cm−2 at 60 °C under 100% relative humidity (RH)

Improved Physicochemical Stability and High Ion Transportation of Poly(Arylene Ether Sulfone) Blocks Containing a Fluorinated Hydrophobic Part for Anion Exchange Membrane Applications

A series of anion exchange membranes composed of partially fluorinated poly(arylene ether sulfone)s (PAESs) multiblock copolymers bearing quaternary ammonium groups were synthesized with controlled lengths of the hydrophilic precursor and hydrophobic oligomer via direct polycondensation. The chloromethylation and quaternization proceeded well by optimizing the reaction conditions to improve hydroxide conductivity and physical stability, and the fabricated membranes were very flexible and transparent. Atomic force microscope images of quaternized PAES (QN-PAES) membranes showed excellent hydrophilic/hydrophobic phase separation and distinct ion transition channels. An extended architecture of phase separation was observed by increasing the hydrophilic oligomer length, which resulted in significant improvements in the water uptake, ion exchange capacity, and hydroxide conductivity. Furthermore, the open circuit voltage (OCV) of QN-PAES X10Y23 and X10Y13 was found to be above 0.9 V, and the maximum power density of QN-PAES X10Y13 was 131.7 mW cm−2 at 60 °C under 100% RH

Photodecarboxylative cyclizations of ω-phthalimido-ortho-phenoxy carboxylates

ω-Phthalimido-ortho-phenoxy carboxylates efficiently undergo photodecarboxylative cyclizations in reasonable to good yields of 12–75%. Although the photocyclization efficiency decreases with increasing carbon chain lengths, target ring sizes up to 15 are successfully realized. Likewise, intermolecular photodecarboxylative additions of ω-phenoxy carboxylates to N-methyl phthalimide give hydroxyphthalimidines in yields of 45–73%

Photoinduced electron transfer cyclizations of aryl-linked phthalimides

The photochemistry of arene-linked phthalimides incorporating the carboxylate or thioether donor group was investigated. Simple N-phthalimidophenyl alkanoates exclusively gave photoreduction (CO2H/H-exchange) products. In contrast, ω-phthalimido-meta-phenoxy carboxylates underwent photodecarboxylative cyclizations in yields of 6–48%. Likewise, catechol-linked derivatives furnished analogue cyclization products in 18–38% yield. Using the photodecarboxylation protocol, macrocyclic target compounds with ring sizes up to 17 could thus be realized. Two model phthalimides containing a thioether branch at the ortho-position of the arene-linker gave the analogue seven-membered cyclization products in yields of 28% and 35%, respectively

Enhanced Performance of a Sulfonated Poly(arylene ether ketone) Block Copolymer Bearing Pendant Sulfonic Acid Groups for Polymer Electrolyte Membrane Fuel Cells Operating at 80% Relative Humidity

The series of sulfonated poly­(arylene ether ketone) (SPAEK) block copolymers with controlled F-oligomer length bearing pendant diphenyl unit were synthesized via a polycondensation reaction. Sulfonation was verified by ¹H NMR analysis to introduce sulfonic acid group selectively and intensively on the pendant diphenyl unit of polymer backbones. The SPAEK membranes fabricated by the solution casting approach were very transparent and flexible with the thickness of ∼50 μm. These membranes with different F-oligomer lengths were investigated to the physiochemical properties such as water absorption, dimensional stability, ion exchange capacity, and proton conductivity. As a result, the SPAEK membranes (X4.8Y8.8, X7.5Y8.8, and X9.1Y8.8) in accordance to increasing the length of hydrophilic oligomer showed excellent proton conductivity in range of 131–154 mS cm^–1 compared to Nafion-115 (131 mS cm^–1) at 90 °C under 100% relative humidity (RH). Among the SPAEK membranes, proton conductivity of SPAEK X9.1Y8.8 (140.7 mS cm^–1) is higher than that of Nafion-115 (102 mS cm^–1) at 90 °C under 80% RH. The atomic force microscopy image demonstrated that number of ion transport channels is increased with increase in the length of hydrophilic oligomer in the main chains, and the morphology is proved to be related to the proton conductivity. The synthesized SPAEK membrane exhibited a maximum power density of 324 mW cm^–2, which is higher than that of Nafion-115 (291 mW cm^–2) at 60 °C under 100% RH

Enhanced performance and durability of composite membranes containing anatase titanium oxide for fuel cells operating under low relative humidity

In this work, sulfonated diblock copolymers (SDBCs) were prepared by polycondensation of sulfonated poly(ether-ether-ketone) (SPEEK) and hydrophobic oligomer, which were combined with sintered anatase titanium oxide (S-An-TiO2) to create a hybrid membrane for apply in proton exchange membrane fuel cells (PEMFCs) operating with low relative humidity (RH). Then, a series of composite membranes (SDBC/S-An-TiO2) were prepared by varying the wt% of S-An-TiO2 blended with SDBC. The results showed that appropriate quantity (ie, 15 wt%) of S-An-TiO2 can significantly improve the proton conductivity and physiochemical properties of prepared composite membrane, as well as the PEMFC performance and durability under 20% RH. The 1.5 wt% of SDBC/S-An-TiO2 offers high current output, power output, and durability values at 60 degrees C under 20% RH, which are 0.207 A cm(-2), 0.074 W cm(-2) and over 90 hours, respectively. These results can be attributed to the good interfacial compatibility between S-An-TiO2 and SDBC. © 2021 John Wiley & Sons Ltd.1