Browsing by Author "Kumar, N"
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- ItemEvaluation of the antidepressant therapeutic potential of isocyanine and pseudoisocyanine analogues of the organic cation decynium-22(Elsevier B. V., 2017-09-08) Krause-Heuer, AM; Fraser-Spears, R; Dobrowolski, JC; Ashford, ME; Wyatt, NA; Roberts, MP; Gould, GG; Cheah, WC; Ng, CKL; Bhadbhade, MM; Zhang, B; Greguric, I; Wheate, NJ; Kumar, N; Koek, W; Callaghan, PD; Daws, LC; Fraser, BHAntidepressant-like activity Herein we describe the synthesis and evaluation of antidepressant properties of seven analogues (1–7) of the low affinity/high capacity transporter blocker decynium-22 (D-22). All analogues (1–7) were synthesized via base promoted coupling reactions between N-alkylated-2-methylquinolinium iodides or N-alkylated-4-methylquinolinium iodides and electrophilic N-alkylated-2-iodoquinolinium iodides. All final compounds were purified by re-crystallization or preparative HPLC and initial evaluation studies included; 1) screening for in vitro α1-adrenoceptor activity (a property that can lead to unwanted side-effects), 2) measuring antidepressant-like activity in a mouse tail suspension test (TST), and 3) measuring effects upon mouse locomotion. The results showed some analogues have lower affinities at α1-adrenoceptors compared to D-22 and showed antidepressant-like activity without the need for co-administration of SSRIs. Additionally, many analogues did not affect mouse locomotion to the same extent as D-22. Plans for additional evaluations of these promising analogues, including measurement of antidepressant-like activity with co-administration of selective serotonin re-uptake inhibitors (SSRIs), are outlined. © 2017 Elsevier B.V.
- ItemA general synthesis of 7-Phenyl-7,13-dihydro-8H-benzo[6,7]azepino[3,2-c]quinolin-8-ones(Thieme, 2019-02-13) Dobrowolski, JC; Nguyen, DHT; Fraser, BH; Bhadbhade, MM; Black, DS; Kumar, NComplex benzazepinoquinolone scaffolds can be accessed from the reaction of 2-aminoacetophenones and oxindole derivatives and feature the seven-membered azepine ring moiety commonly found in a range of drug molecules. The described reaction is generally applicable and allows for rapid access to a diverse range of new structures with further potential to build more elaborate molecules. © 2021 Georg Thieme Verlag KG
- ItemA general synthesis of benzoazepinoindoles – a new class of heterocycles(Thieme, 2019-10-09) Dobrowolski, JC; Nguyen, DHT; Fraser, BH; Bhadbhade, MM; Black, DS; Kumar, NA new class of heterocyclic compounds, namely the benzoazepinoindolones, has been synthesised through a base-catalysed cyclisation reaction of 1,4-bis(2-aminophenyl)-2-phenylbutane-1,4-dione derivatives and features the prominent seven-membered azepine ring moiety. This synthesis has considerable scope for the rapid generation of more complex structures and is inexpensive and generally applicable. © 2019 Georg Thieme Verlag
- ItemHierarchical assembly of tryptophan zipper peptides into stress-relaxing bioactive hydrogels(Springer Nature, 2023-10-23) Nguyen, AK; Molley, TG; Kardia, E; Ganda, S; Chakraborty, S; Wong, SL; Ruan, JF; Yee, BE; Mata, JP; Vijayan, A; Kumar, N; Tilley, RD; Waters, SA; Kilian, KASoft materials in nature are formed through reversible supramolecular assembly of biological polymers into dynamic hierarchical networks. Rational design has led to self-assembling peptides with structural similarities to natural materials. However, recreating the dynamic functional properties inherent to natural systems remains challenging. Here we report the discovery of a short peptide based on the tryptophan zipper (trpzip) motif, that shows multiscale hierarchical ordering that leads to emergent dynamic properties. Trpzip hydrogels are antimicrobial and self-healing, with tunable viscoelasticity and unique yield-stress properties that allow immediate harvest of embedded cells through a flick of the wrist. This characteristic makes Trpzip hydrogels amenable to syringe extrusion, which we demonstrate with examples of cell delivery and bioprinting. Trpzip hydrogels display innate bioactivity, allowing propagation of human intestinal organoids with apical-basal polarization. Considering these extensive attributes, we anticipate the Trpzip motif will prove a versatile building block for supramolecular assembly of soft materials for biotechnology and medicine. © 2023 Springer Nature Limited. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License.
- ItemProbing the structure of nanochannal arrays by electrostatic force microscopy(World Scientific Publishing Co., 2011-04-01) Murugaraj, P; Kumar, N; Jakubov, T; Mainwaring, DE; Siegele, RElectrostatic force microscopy (EFM) represents a versitile tool for the characterisation of electric and dielectric structures at nanoscale which can be employed to provide charge distributions associated with such nanotopologies. EFM-phase profiles show only the variation of electrostatic force which is strongly influenced by the surface conductivity of nanostructured arrays providing improved definition compared to conventional AFM. Here we apply it to carbon nanochannel arrays embedded within polyimide dielectric matrices. © 2012 World Scientific Publishing Co.