8 research outputs found
Rendering polyurethane hydrophilic for efficient cellulose reinforcement in melt-spun nanocomposite fibers
Many commodity plastics, such as thermoplastic polyurethanes (PUs), require reinforcement for use as commercial products. Cellulose nanocrystals (CNCs) offer a âgreenâ and scalable approach to polymer reinforcement as they are exceptionally stiff, recyclable, and abundant. Unfortunately, achieving efficient CNC reinforcement of PUs with industrial melt processing techniques is difficult, mostly due to the incompatibility of the hydrophobic PU with hydrophilic CNCs, limiting their dispersion. Here, a hydrophilic PU is synthesized to achieve strong reinforcement in meltâprocessed nanocomposite fibers using filter paperâsourced CNCs. The meltâspun fibers, exhibiting smooth surfaces even at high CNC loading (up to 25 wt%) indicating good CNC dispersion, are benchâmarked against solventâcast filmsâsolvent processing is not scalable but disperses CNCs well and produces strong CNC reinforcement. Mechanical analysis shows the CNC addition stiffens both nanocomposite films and fibers. The stress and strain at break, however, are not significantly affected in films, whereas adding CNCs to fibers increases the stressâatâbreak while reducing the strainâatâbreak. Compared to earlier studies employing a hydrophobic (and stiffer) PU, CNC addition to a hydrophilic PU substantially increases the fiber stiffness and strength. This work therefore suggests that rendering thermoplastics more hydrophilic might pave the way for âgreenerâ polymer composite products using CNCs
Electrospinning of Cellulose Nanocrystal-Reinforced Polyurethane Fibrous Mats
We report the electrospinning of mechanically-tunable, cellulose nanocrystal (CNC)-reinforced polyurethanes (PUs). Using high-aspect ratio CNCs from tunicates, the stiffness and strength of electrospun PU/CNC mats are shown to generally increase. Furthermore, by tuning the electrospinning conditions, fibrous PU/CNC mats were created with either aligned or non-aligned fibers, as confirmed by scanning electron microscopy. PU/CNC mats having fibers aligned in the strain direction were stiffer and stronger compared to mats containing non-aligned fibers. Interestingly, fiber alignment was accompanied by an anisotropic orientation of the CNCs, as confirmed by wide-angle X-ray scattering, implying their alignment additionally benefits both stiffness and strength of fibrous PU/CNC nanocomposite mats. These findings suggest that CNC alignment could serve as an additional reinforcement mechanism in the design of stronger fibrous nanocomposite mats
Discovery of 3-alkyl-5-aryl-1-pyrimidyl-1H-pyrazole derivatives as a novel selective inhibitor scaffold of JNK3
3-alkyl-5-aryl-1-pyrimidyl-1H-pyrazole derivatives were designed and synthesised as selective inhibitors of JNK3, a target for the treatment of neurodegenerative diseases. Following previous studies, we have designed JNK3 inhibitors to reduce the molecular weight and successfully identified a lead compound that exhibits equipotent activity towards JNK3. Kinase profiling results also showed high selectivity for JNK3 among 38 kinases. Among the derivatives, the IC50 value of 8a, (R)-2-(1-(2-((1-(cyclopropanecarbonyl)pyrrolidin-3-yl)amino)pyrimidin-4-yl)-5-(3,4-dichlorophenyl)-1H-pyrazol-3-yl)acetonitrile exhibited 227ânM, showing the highest inhibitory activity against JNK3
Peptide-reinforced amphiphilic polymer conetworks
Amphiphilic polymer conetworks (APCN) are polymer networks composed of hydrophilic and hydrophobic chain segments. Their applications range from soft contact lenses to membranes and biomaterials. APCNs based on polydimethylsiloxane (PDMS) and poly(2-hydroxyethyl acrylate) (PHEA) are flexible and elastic in the dry and the swollen state. However, they are not good at resisting deformation under load, i.e. their toughness is low. A bio-inspired approach to reinforce APCNs is presented based on the incorporation of poly(ÎČ-benzyl-aspartate) (PBLA) blocks between crosslinking points and PDMS chain segments. The mechanical properties of the resulting peptide-reinforced APCNs can be tailored by the secondary structure of the peptide chains (ÎČ-sheets or a mixture of α-helices and ÎČ-sheets). Compared to non-reinforced APCNs, the peptide-reinforced networks have higher extensibility (53 vs. up to 341%), strength (0.71 ± 0.16 vs. 22.28 ± 2.81 MPa) and toughness (0.10 ± 0.04 vs. up to 4.85 ± 1.32 MJ m-3), as measured in their dry state. The PBLA peptides reversibly toughen and reinforce the APCNs, while other key material properties of APCNs are retained, such as optical transparency and swellability in water and organic solvents. This paves the way for applications of APCNs that benefit from significantly increased mechanical properties
Peptideâreinforced amphiphilic polymer conetworks
Amphiphilic polymer conetworks (APCNs) are polymer networks composed of hydrophilic and hydrophobic chain segments. Their applications range from soft contact lenses to membranes and biomaterials. APCNs based on polydimethylsiloxane (PDMS) and poly(2âhydroxyethyl acrylate) are flexible and elastic in the dry and swollen state. However, they are not good at resisting deformation under load, i.e., their toughness is low. A bioâinspired approach to reinforce APCNs is presented based on the incorporation of poly(ÎČâbenzylâLâaspartate) (PBLA) blocks between crossâlinking points and PDMS chain segments. The mechanical properties of the resulting peptideâreinforced APCNs can be tailored by the secondary structure of the peptide chains (ÎČâsheets or a mixture of αâhelices and ÎČâsheets). Compared to nonâreinforced APCNs, the peptideâreinforced networks have higher extensibility (53 vs. up to 341%), strength (0.71 ± 0.16 vs. 22.28 ± 2.81 MPa), and toughness (0.10 ± 0.04 vs. up to 4.85 ± 1.32 MJ mâ»Âł), as measured in their dry state. The PBLA peptides reversibly toughen and reinforce the APCNs, while other key material properties of APCNs are retained, such as optical transparency and swellability in water and organic solvents. This paves the way for applications of APCNs that benefit from significantly increased mechanical properties
Anti-Inflammatory Activity of Cajanin, an Isoflavonoid Derivative Isolated from <i>Canavalia lineata</i> Pods
The bioactive components of Canavalia lineata (Thunb.) DC pods were investigated using bioactivity-guided isolation, and the chemical structures of flavonoids 1â3, isoflavonoid derivatives 4â11, and phenolic compounds 12 and 13 were identified by comparing NMR, MS, and CD spectral data with previously reported spectroscopic data. Compounds 1â13 were evaluated for their anti-inflammatory effects on LPS-stimulated RAW264.7 macrophages. Among these compounds, the isoflavonoid derivative cajanin (7) exhibited the most potent anti-inflammatory activity (IC50 of NO = 19.38 ± 0.05 ”M; IC50 of IL-6 = 7.78 ± 0.04 ”M; IC50 of TNF-α = 26.82 ± 0.11 ”M), exerting its anti-inflammatory effects by suppressing the activation and nuclear translocation of the transcription factor NF-ÎșB by phosphorylating IÎșB and p65. These results suggested that cajanin (7) may be a potential candidate for improving the treatment of inflammatory diseases
Korean Validation of the Short Version of the TEMPS-A (Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Autoquestionnaire) in Patients with Mood Disorders
Background and Objectives: The Temperament Evaluation of Memphis, Pisa, Paris and San Diego Autoquestionnaire (TEMPS-A) is designed to assess affective temperaments. The short version of the TEMPS-A (TEMPS-A-SV) has been translated into various languages for use in research and clinical settings. However, no research has been conducted to validate the Korean version of the TEMPS-A-SV in patients with mood disorders. The goal of this study is to evaluate the reliability and validity of the TEMPS-A-SV in Korean mood disorder patients. Materials and Methods: In this cross-sectional retrospective study, a total of 715 patients (267 patients with major depressive disorder, 94 patients with bipolar disorder I, and 354 patients with bipolar disorder II) completed the Korean TEMPS-A-SV. Cronbachâs alpha and McDonaldâs omega were used to assess the reliability. Exploratory factor analysis (EFA) was also performed. Spearmanâs correlation coefficient was used to examine associations between the five temperaments. The difference in five temperament scores between the gender or diagnosis groups was analyzed, and the correlation between five temperament scores and age was tested. Results: The Korean TEMPS-A-SV displayed good internal consistency (α = 0.65â0.88, Ï = 0.66â0.9) and significant correlations between the subscales except one (the correlation between hyperthymic and anxious). Using EFA, a two-factor structure was produced: Factor I (cyclothymic, depressive, irritable, and anxious) and Factor II (hyperthymic). The cyclothymic temperament score differed by gender and the anxious temperament score was significantly correlated with age. All the temperaments, except for irritable temperament, showed significant differences between diagnosis groups. Conclusions: Overall, the results show that the TEMPS-A-SV is a reliable and valid measurement that can be used for estimating Koreansâ affective temperaments. However, more research is required on affective temperaments and associated characteristics in people with mood disorders