Synthesis and characterization of novel cardo-containing copolyimide membranes for gas separation and effect of bulky site in the polymer backbone

A significant issue in environmental science is the climate change caused by global warming. The increase in the global temperature could lead to a range of negative effects that include rising sea levels, changes in ecosystems, loss of biodiversity, and reduction in crop yields. Currently, it is generally accepted that greenhouse gases such as carbon dioxide, methane, nitrous oxide, and fluorinated gases from fossil fuels and industrial wastes are primarily responsible for global warming. One method of slowing the rate of global warming is to reduce carbon dioxide emission into the air and to substitute fossil fuel for alternative energy sources. There are many methods of reducing greenhouse gas emissions, including improvements of energy efficiency, use of non-fossil fuel power sources, improved soil management, and the geological sequestration of carbon dioxide from significant greenhouse gas producing point sources. However, the most feasible and practical method at this moment is to capture the greenhouse gases from the fossil fuel combustion using amine absorption, physical adsorption, and membranes, etc. Membrane technology has been used for more than 50 years, and gas separation using membranes is used in several industrial processes such as the production of nitrogen from air, the separation of CO2 and H2O from natural gas, the purification of H2, and the recovery of vapors from vent gases, because it has various advantages such as low capital investment, ease of operation, and low energy consumption. To overcome the disadvantage of polyimide based materials in manufacturing and processing, researchers have developed various methods such as the introduction of flexible monomers, or chemical and thermal post-modification. One method to improve the properties of the membrane is the post-fabrication and thermal process, i.e. the thermally rearranged (TR) PBO membranes that exhibit excellent separation properties and superior thermal and chemical properties compared with commercialized engineering plastics. TR polymer membranes can be obtained from soluble polyimide containing functional groups such as –OH and –SH. The microcavity structure and distribution of soluble polyimide membranes are evolved during thermal treatment. In this study, we focus on the polyimide syntheses using both strategies of the introduction of bulky monomers and post-thermal treatments, yielding . synthesized 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA)-based copolyimide and hydroxyl monomer via polycondensation. In order to improve the gas separation properties and processability, we used highly CO2 permeable and selective monomers in the synthesis, and then evaluated the effect of the mole ratio monomers of the polymer on the gas separation performance. Finally, the copolyimide membrane was converted to a PBO structure via a thermal treatment in order to increase the rigidity and free volume of the polymer backbone. The degree of thermal conversion was controlled through varying the composition of the copolyimide. Then, the performances of the TR membranes were evaluated regarding their change in chemical structure, mechanical and thermal stability, and gas separation properties

Editorial introduction: Green Planning

This special issue deals with research presented at the biannual SPSD conference held in Seoul, South Korea in 2017. Specifically, about half of the presentations (total 68) were submitted in full length, aiming for official publication in IRSPSD and from these, this issue was initially based on nine papers. Five papers were finally accepted and comprise this special issue

EFFECTS OF LIQUID SWIRLING ON GAS-TO-LIQUID MASS TRANSFER IN THREE-PHASE FLUIDIZED BEDS

The swirling flow mode of liquid phase was adopted to promote the gas-to-liquid mass transfer in three-phase(gas-liquid-solid) fluidized beds. Effects of gas(0.01-0.09m/s) and liquid(0.035-0.172m/s) velocities, particle size(1.7-6.0mm) and swirling ratio of liquid phase(0-0.5) on the volumetric gas-to-liquid mass transfer coefficient in the bed were examined. The mass transfer coefficient increased up to 70% by adjusting the swirling flow of liquid phase, especially when the gas velocity is relatively low range. The value of gas-to-liquid mass transfer coefficient was well correlated in terms of dimensionless groups which were derived from the dimensional analysis on the mass transfer system

Okanin, a chalcone found in the genus Bidens, and 3-penten-2-one inhibit inducible nitric oxide synthase expression via heme oxygenase-1 induction in RAW264.7 macrophages activated with lipopolysaccharide

Excess production of nitric oxide by activated macrophages via inducible nitric oxide synthase leads to the development of various inflammatory diseases. Heme oxygenase-1 expression via activation of nuclear factor-erythroid 2-related factor 2 inhibits nitric oxide production and inducible nitric oxide synthase expression in activated macrophages. Okanin is one of the most abundant chalcones found in the genus Bidens (Asteraceae) that is used as various folk medications in Korea and China for treating inflammation. Here, we found that okanin (possessing the α-β unsaturated carbonyl group) induced heme oxygenase-1 expression via nuclear factor-erythroid 2-related factor 2 activation in RAW264.7 macrophages. 3-Penten-2-one, of which structure, as in okanin, possesses the α-β unsaturated carbonyl group, also induced nuclear factor-erythroid 2-related factor 2-dependent heme oxygenase-1 expression, while both 2-pentanone (lacking a double bond) and 2-pentene (lacking a carbonyl group) were virtually inactive. In lipopolysaccharide-activated RAW264.7 macrophages, both okanin and 3-penten-2-one inhibited nitric oxide production and inducible nitric oxide synthase expression via heme oxygenase-1 expression. Collectively, our findings suggest that by virtue of its α-β unsaturated carbonyl functional group, okanin can inhibit nitric oxide production and inducible nitric oxide synthase expression via nuclear factor-erythroid 2-related factor 2-dependent heme oxygenase-1 expression in lipopolysaccharide-activated macrophages

Inflammatory Polyarthritis in a Patient with Psoriasis: Is It Psoriatic Arthritis or Rheumatoid Arthrirtis?

Psoriatic arthritis (PsA) is an inflammatory arthritis associated with psoriasis. There are no generally accepted diagnostic criteria for PsA. Indeed, the diagnosis of this inflammatory arthritis is made by exclusion of other possible diseases and based upon immunologic, radiologic, and clinical features which are consistent with the diagnosis. Inflammatory arthritis in a patient with psoriasis can be an important clue for the diagnosis of PsA, but the possibility for diagnosis of other inflammatory arthritides ever remains. Herein we report a case of a female patient who was not diagnosed with PsA, but with rheumatoid arthritis, even though she had psoriasis

Long-term survival benefits of intrathecal autologous bone marrow-derived mesenchymal stem cells (Neuronata-R®: lenzumestrocel) treatment in ALS: Propensity-score-matched control, surveillance study

ObjectiveNeuronata-R® (lenzumestrocel) is an autologous bone marrow-derived mesenchymal stem cell (BM-MSC) product, which was conditionally approved by the Korean Ministry of Food and Drug Safety (KMFDS, Republic of Korea) in 2013 for the treatment of amyotrophic lateral sclerosis (ALS). In the present study, we aimed to investigate the long-term survival benefits of treatment with intrathecal lenzumestrocel.MethodsA total of 157 participants who received lenzumestrocel and whose symptom duration was less than 2 years were included in the analysis (BM-MSC group). The survival data of placebo participants from the Pooled-Resource Open-Access ALS Clinical Trials (PROACT) database were used as the external control, and propensity score matching (PSM) was used to reduce confounding biases in baseline characteristics. Adverse events were recorded during the entire follow-up period after the first treatment.ResultsSurvival probability was significantly higher in the BM-MSC group compared to the external control group from the PROACT database (log-rank, p < 0.001). Multivariate Cox proportional hazard analysis showed a significantly lower hazard ratio for death in the BM-MSC group and indicated that multiple injections were more effective. Additionally, there were no serious adverse drug reactions found during the safety assessment, lasting a year after the first administration.ConclusionThe results of the present study showed that lenzumestrocel treatment had a long-term survival benefit in real-world ALS patients

Definitive Radiation Therapy for Early Glottic Cancer: Experience of Two Fractionation Schedules

ObjectivesThe authors would report the results of definitive radiation therapy (RT) for early glottic cancer by two different radiation dose schedules.MethodsFrom February of 1995 till June of 2008, 157 patients with T1-2N0 glottic cancer were treated with curative RT at Samsung Medical Center. All patients had squamous cell carcinoma, and there were 89 patients (56.7%) with T1a, 36 (22.9%) with T1b, and 32 (20.4%) with T2. Two different radiation dose schedules were used: 70 Gy in 35 fractions to 64 patients (40.8%, group A); and 67.5 Gy in 30 fractions to 93 patients (59.2%, group B). The median treatment durations were 50 days (range, 44 to 59 days) and 44 days (range, 40 to 67 days) in the groups A and B, respectively.ResultsThe median follow-up durations were 85 and 45 months for the groups A and B. No severe late complication of RTOG grade 3 or higher was observed, and there was no difference in acute or chronic complication between the groups. Twenty-four patients experienced treatment failure: local recurrence only in 19 patients; regional recurrence only in one; combined local and regional recurrence in four; and systemic metastasis in none. The overall 5-year disease-free survival and disease-specific survival rates were 84.7% and 94.8%. The disease-free survival rate in the group B was better (78.3% vs. 90.8%, P=0.031). This difference was significant only in T1 stage (83.4% vs. 94.6%, P=0.025), but not in T2 (62.7% vs. 60.6%, P=0.965). Univariate analysis showed that the tumor extent, cord mobility, T-stage, and the dose schedule had significant influence on the disease-free survival, and multivariate analysis showed that only the tumor extent and the dose schedule were associated with the disease-free survival.ConclusionSuperior disease-free survival could be achieved by 2.25 Gy per fraction without increased toxicity over shorter RT duration, when compared with 2.0 Gy per fraction

The Impact of Fasciation on Maize Inflorescence Architecture

How functional genetics research can be applied to improving crop yields is a timely challenge. One of the most direct methods is to produce larger inflorescences with higher productivity, which should be accompanied by a balance between stem cell proliferation and lateral organ initiation in meristems. Unbalanced proliferation of stem cells causes the fasciated inflorescences, which reflect the abnormal proliferation of meristems, derived from the Latin word ‘fascis’, meaning ‘bundle’. Maize, a model system for grain crops, has shown tremendous yield improvements through the mysterious transformation of the female inflorescence during domestication. In this review, we focus on maize inflorescence architecture and highlight the patterns of fasciation, including recent progress