Preparation And Evaluation Of Mangrove Tannins-Based Adsorbent For The Removal Of Heavy Metal Ions From Aqueous Solution [QD327. C559 2008 f rb].

Struktur oligomer poliflavonoid tanin bakau yang diekstrak daripada kulit bakau Rhizophora apiculata dan prestasi penjerap berasaskan tanin (TBA) terhadap penjerapan ion logam berat daripada larutan akueus telah dikaji. The polyflavonoid oligomeric structures of mangrove tannins extracted from the barks of Rhizophora apiculata and performance of tannins-based adsorbent (TBA) on the adsorption of heavy metal ions from the aqueous solutions were explored

A Simple Approach to Distinguish Classic and Formaldehyde-Free Tannin Based Rigid Foams by ATR FT-IR

Tannin based rigid foams (TBRFs) have been produced with formaldehyde since 1994. Only recently several methods have been developed in order to produce these foams without using formaldehyde. TBRFs with and without formaldehyde are visually indistinguishable; therefore a method for determining the differences between these foams had to be found. The attenuated total reflectance infrared spectroscopy (ATR FT-IR) investigation of the TBRFs presented in this paper allowed discrimination between the formaldehyde-containing (classic) and formaldehyde-free TBRFs.Thespectra of the formaldehyde-free TBRFs, indeed, present decreased band intensity related to the C–O stretching vibration of (i) the methylol groups and (ii) the furanic rings. This evidence served to prove the chemical difference between the two TBRFs and explained the slightly higher mechanical properties measured for the classic TBRFs

4-Hy­droxy-3-[(4-hy­droxy-6-methyl-2-oxo-3,6-dihydro-2H-pyran-3-yl)(3-thien­yl)meth­yl]-6-methyl-3,6-dihydro-2H-pyran-2-one

The asymmetric unit of the title compound, C17H14O6S, contains four crystallographically independent mol­ecules in which the pyran­one units are essentially planar, with maximum deviations of 0.016 (2), 0.019 (2), 0.025 (2), 0.014 (2), 0.020 (2), 0.010 (2), 0.003 (2) and 0.012 (2) Å. One of the thio­phene rings is disordered over two positions, with an occupancy ratio of 0.739 (4):0.261 (4). The dihedral angles between the two pyran­one rings in the independent mol­ecules are 59.42 (8), 48.67 (8), 60.62 (9) and 51.60 (8)°. In the crystal, mol­ecules are linked through inter­molecular O—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network

3-[(E)-3-(2,4-Dichloro­phen­yl)prop-2-en­oyl]-4-hy­droxy-2H-chromen-2-one

In the title compound, C18H10Cl2O4, the chromen-2-one ring system is almost planar [maximum deviation = 0.028 (1) Å] and is inclined at an angle of 16.35 (4)° with respect to the benzene ring. The C=C bond has an E configuration. The mol­ecular conformation is stabilized by an almost symmetric intra­molecular O⋯H⋯O hydrogen bond and a C—H⋯O inter­action, both of which form S(6) ring motifs. In the crystal structure, mol­ecules are linked into sheets lying parallel to (100) via inter­molecular C—H⋯O hydrogen bonds. The crystal packing is further consolidated by π–π stacking inter­actions [centroid-to-centroid separation = 3.6615 (6) Å]

3-[5-(2,4-Dichloro­phen­yl)-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl]-4-hy­droxy-2H-chromen-2-one

In the title compound, C24H16Cl2N2O3, the chromene ring system is almost planar, with a maximum deviation of 0.042 (1) Å. It makes dihedral angles of 3.72 (6), 73.37 (5) and 12.00 (5)° with the dihydro­pyrazole, benzene and phenyl rings, respectively. An intra­molecular O—H⋯N hydrogen bond forms an S(6) ring motif. In the crystal, mol­ecules are linked via C—H⋯O inter­actions, forming an infinite chain along the a axis. The crystal packing is further stabilized by a π–π stacking inter­action [centroid–centroid distance = 3.5471 (7) Å] and a Cl⋯Cl short contact [Cl⋯Cl = 3.214 (1) Å]

3-Methyl-4-[(E)-3-thien­ylmethyl­idene­amino]-1H-1,2,4-triazole-5(4H)-thione

The asymmetric unit of the title compound, C8H8N4S2, contains two crystallographically independent mol­ecules. The thio­phene ring of one mol­ecule is disordered over two positions with refined site occupancies of 0.6375 (19) and 0.3625 (19). One mol­ecule is almost planar and the other one is twisted, the dihedral angles between the thio­phene and triazole rings being 7.28 (7) and 48.9 (2)° [48.5 (4)° for the minor component], respectively. An intra­molecular C—H⋯S hydrogen bond stabilizes the mol­ecular conformation of the planar molecule. In the crystal, the two mol­ecules are inter­connected by N—H⋯S hydrogen bonds into dimers, which are further consolidated into chains along the b axis by C—H⋯N hydrogen bonds. Weak C–H⋯π and π–π inter­actions [centroid–centroid distance = 3.5149 (7) Å] are also observed

4-Hy­droxy-3-[(4-hy­droxy-6,7-dimethyl-2-oxo-2H-chromen-3-yl)(4-oxo-4H-chromen-3-yl)meth­yl]-6,7-dimethyl-2H-chromen-2-one

In the title compound, C32H24O8, the mol­ecular structure is disordered over two positions with refined site occupancies of 0.8746 (10) and 0.1254 (10). The mean plane of the three chromeno rings make dihedral angles with each other of 65.12 (4), 62.91 (4) and 59.70 (4)° in the major occupancy component and 59.1 (3), 66.1 (3) and 58.8 (3)° in the minor component. Intra­molecular O—H⋯O hydrogen bonds stabil­ize the mol­ecular structure and the crystal structure is stabilized by weak C–H⋯π and π–π inter­actions [centroid–centroid distances 3.496 (6)–3.672 (7) Å]

9-(7-Fluoro-4-oxo-4H-chromen-3-yl)-3,3,6,6-tetra­methyl-2,3,4,5,6,7,8,9-octa­hydro-1H-xanthene-1,8-dione

In the title compound, C26H25FO5, the terminal cyclo­hexane rings of the xanthene ring system adopt half-boat conformations. The 4H-chromene ring make a dihedral angle of 87.94 (5)° with the xanthene ring system and its carbonyl O atom lies above the xanthene O atom. In the crystal, mol­ecules are linked into ribbons propagating along the a-axis direction by C—H⋯O hydrogen bonds. Aromatic π–π stacking inter­actions [centroid–centroid distance = 3.7367 (12) Å] also occur

Overview of neurological mechanism of pain profile used for animal “pain-like” behavioral study with proposed analgesic pathways

Pain is the most common sensation installed in us naturally which plays a vital role in defending us against severe harm. This neurological mechanism pathway has been one of the most complex and comprehensive topics but there has never been an elaborate justification of the types of analgesics that used to reduce the pain sensation through which specific pathways. Of course, there have been some answers to curbing of pain which is a lifesaver in numerous situations—chronic and acute pain conditions alike. This has been explored by scientists using pain-like behavioral study methodologies in non-anesthetized animals since decades ago to characterize the analgesic profile such as centrally or peripherally acting drugs and allowing for the development of analgesics. However, widely the methodology is being practiced such as the tail flick/Hargreaves test and Von Frey/Randall–Selitto tests which are stimulus-evoked nociception studies, and there has rarely been a complete review of all these methodologies, their benefits and its downside coupled with the mechanism of the action that is involved. Thus, this review solely focused on the complete protocol that is being adapted in each behavioral study methods induced by different phlogogenic agents, the different assessment methods used for phasic, tonic and inflammatory pain studies and the proposed mechanism of action underlying each behavioral study methodology for analgesic drug profiling. It is our belief that this review could significantly provide a concise idea and improve our scientists’ understanding towards pain management in future research