Chromene Carbohydrazide- Schiff Base as a Highly Selective Turn-Off Fluorescence Chemosensor for In3+ Ion and its Application.

A new 7-(diethylamino)-2-oxo-2 H-chromene-3-carbohydrazide design to synthesize a simple Schiff-base condition. The synthesized molecules' (probe L) photophysical properties were investigated in various solvent systems and solvent-poor-solvent assays. Probe L exhibits the absorbance band at 440 nm and the emission band at 488 nm in DMSO: H2O (7:3, v/v). Further, probe L shows selective turn-off emission recognition of In3+ ions in DMSO: H2O (7:3, pH = 7.4). By Job's plot and ESI mass analysis, probe L forms a 1:2 stoichiometry complex with an estimated association constant of 4.04 × 104 M- 2 with In3+ ions. Metal induces CHEQ (chelation-caused fluorescence quenching) to reduce the intensity of probe L's emission, and the estimated quenching constant was 4.52 × 104 M- 1. The limit of detection was found to be 5.93 nM; the time response of the sensor is instantaneous, and its reversible nature was confirmed using EDTA additions. Solid substrates (test strips) were designed and tested for fast, reliable, user-friendly, and real-time sensing of In3+ ions for on-site applications. The binding mechanism of probe L with In3+ ions was investigated using 1H NMR titration and DFT/TD-DFT studies.

N'-[(E)-3-Bromo-5-chloro-2-hy-droxy-benzyl-idene]furan-2-carbohydrazide.

In the title compound, C12H8BrClN2O3, the furan ring makes a dihedral angle of 17.2 (2)° with the six-membered ring. An intra-molecular O-H⋯N hydrogen bond stabilizes the mol-ecular conformation. In the crystal, N-H⋯O hydrogen bonds connect the mol-ecules into chains running along the c-axis direction. The crystal packing is additionally stabilized by C-H⋯O inter-actions into a three-dimensional supramolecular architecture.

Bone disease in thyrotoxicosis.

Thyrotoxicosis, a clinical syndrome characterized by manifestations of excess thyroid hormone, is one of the commonly-recognised conditions of the thyroid gland. Thyrotoxicosis causes acceleration of bone remodelling and though it is one of the known risk factors for osteoporosis, the metabolic effects of thyroxine on bone are not well discussed. Studies show that thyroid hormones have effects on bone, both in vitro and in vivo. Treatment of thyrotoxicosis leads to reversal of bone loss and metabolic alterations, and decreases the fracture risk. There are limited studies in India as to whether these changes are fully reversible. In this review we discuss about the effects of thyrotoxicosis (endogenous and exogenous) on bone and mineral metabolism, effects of subclinical thyrotoxicosis on bone and mineral metabolism and effects of various forms of treatment in improving the bone mineral density in thyrotoxicosis.

4-Chloro-2-[(2,6-diisopropyl-phen-yl)imino-meth-yl]phenol.

The asymmetric unit of the title compound, C(19)H(22)ClNO, contains two independent mol-ecules in which the dihedral angles between the aromatic rings are 76.45 (9) and 74.69 (9)°. An intra-molecular O-H⋯N hydrogen bond occurs in each mol-ecule. The crystal structure features weak C-H⋯π inter-actions.

(E)-4-Bromo-2-[(2,6-diisopropyl-phen-yl)imino-meth-yl]phenol.

In the title compound, C(19)H(22)BrNO, the dihedral angle between the benzene rings is 76.17 (14)° and an intra-molecular O-H⋯N hydrogen bond with an S(6) graph-set motif is present. One methyl group is disordered over two sets of sites with site occupancies of 0.66 (3) and 0.34 (3). A weak inter-molecular C-H⋯π inter-action is observed in the crystal structure.

2-[(2,6-Diisopropyl-phen-yl)imino-meth-yl]-4-iodo-phenol.

The asymmetric unit of title compound, C(19)H(22)INO, contains two independent mol-ecules. Classical intra-molecular O-H⋯N hydrogen bonds stabilize the mol-ecular structures. The crystal structure is stabilized by weak inter-molecular C-H⋯π and π-π [centroid-centroid = 3.8622 (18) Å] inter-actions. In both mol-ecules, the aromatic rings are nearly perpendicular to each other [dihedral angles = 84.26 (17) and 86.69 (15)°].

The influence of sunlight on the localized corrosion of UNS S31600 in natural seawater.

Tests were conducted on the performance of UNS S31600 stainless steel (SS) in a natural day/night cycle vs full darkness under conditions of natural marine biofilm accumulation. In quiescent flowing seawater tests in the laboratory as well as under natural immersion in the sea, diffuse sunlight (∼10% of natural) counteracted the influence of marine biofilms and produced substantial inhibition of the corrosion of SS. Thus, the probabilities (percentage attack) and propagation rates (depths of attack) in multiple crevice tests were substantially lower in the day/night cycle than in the dark. A benefit was also observed for welded SS in terms of the time to corrosion initiation and the mass loss. SS in the passive state showed broader passive regions, well-defined breakdown potentials and markedly smaller anodic and cathodic current densities under the diurnal cycle. The overall reduction in corrosion is attributed to a combination of electrochemical photoinhibition and simultaneous photoinactivation of microbially mediated metal redox reactions linked to cathodic kinetics. These data offer fresh insights into the behaviour of SS under practical seawater situations and the proposed potential use of illumination in the mitigation of biologically influenced consequences.

N'-[(E)-2-Hy-droxy-3,5-diiodo-benzyl-idene]pyridine-3-carbohydrazide.

In the title compound, C(13)H(9)I(2)N(3)O(2), the dihedral angle between the two aromatic rings is 10.5 (2)°. The mol-ecule displays a trans configuration with respect to the C=N bond. An intra-molecular O-H⋯N hydrogen bond occurs. The crystal packing is stabilized by N-H⋯O and C-H⋯O hydrogen bonds.

N'-[(1E)-4-Diethyl-amino-2-hy-droxy-benz-idene]benzohydrazide.

In the title compound, C(18)H(21)N(3)O(2), the dihedral angle between the phenyl and benzene rings is 36.85 (10)°. The methyl C atom of one of the ethyl groups is disordered over two positions with site occupancies of 0.810 (8) and 0.190 (8). The mol-ecular structure is stabilized by a classical intra-molecular O-H⋯N hydrogen bond. The crystal structure exhibits weak inter-molecular N-H⋯O, C-H⋯O and C-H⋯π inter-actions.

4-[(E)-(4-Diethyl-amino-2-hy-droxy-benzyl-idene)amino]-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one.

In the title compound, C(22)H(26)N(4)O(2), the phenyl ring and hy-droxy-benzene group are twisted with respect to the central pyrazolone ring, making dihedral angles of 54.05 (5) and 21.80 (6)°, respectively. One of the ethyl groups is disordered over two positions with site occupancies of 0.872 (6) and 0.128 (6). The mol-ecular structure features short intra-molecular O-H⋯N and C-H⋯O contacts. The crystal packing exhibits weak inter-molecular C-H⋯O and C-H⋯π inter-actions.

2,4-Diiodo-6-{[4-(morpholin-4-yl)phenyl]iminomethyl}phenol.

In the title compound, C(17)H(16)I(2)N(2)O(2), the two aromatic rings are almost coplanar [dihedral angle 2.57 (15)°]. The morpholine ring adopts a chair conformation. The mol-ecular structure is stabilized by an O-H⋯N hydrogen bond and the crystal packing exhibits weak inter-molecular C-H⋯O and π-π [centroid-to-centroid distances 3.663 (3)-4.073 (3) Å] inter-actions.

N'-[(E)-2-Hy-droxy-3,5-diiodo-benzyl-idene]cyclo-hexa-ne-1-carbohydrazide.

In the title compound, C(14)H(10)I(2)N(2)O(2), the two aromatic rings are inclined at a dihedral angle of 16.72 (33)°. The mol-ecular structure is stabilized by an intra-molecular O-H⋯N hydrogen bond. In the crystal, inter-molecular N-H⋯O inter-actions link the mol-ecules into chains running along the c axis. C-H⋯O inter-actions also occur. The crystal used for the structure determination was a non-merohedral twin with a domain ratio of 0.972 (2):0.028 (2).

5-Meth-oxy-2-{[4-(morpholin-4-yl)phen-yl]imino-meth-yl}phenol.

In the title compound, C(18)H(20)N(2)O(3), the dihedral angle between the two aromatic rings is 33.66 (6)°. The morpholine ring adopts a chair conformation. The mol-ecular structure is stabilized by an intra-molecular O-H⋯N hydrogen bond. In the crystal, mol-ecules are linked via weak inter-molecular C-H⋯O and C-H⋯π inter-actions.

(E)-N'-(3-Bromo-5-chloro-2-hy-droxy-benzyl-idene)nicotinohydrazide.

There are two independent mol-ecules in the asymmetric unit of the title compound, C(13)H(9)BrClN(3)O(2), in which the dihedral angles between the benzene and pyridine rings are 8.23 (9)° and 52.84 (12)°. Both the mol-ecules exist in an E configuration with respect to the C=N double bond. The two mol-ecules in the asymmetric unit are linked via weak C-H⋯O hydrogen bonds. In both the mol-ecules, an intra-molecular O-H⋯N hydrogen bond generate an S(6) graph-set motif. In the crystal, inter-molecular N-H⋯O and C-H⋯O hydrogen bonds generate bifurcated R(1) (2)(7) ring motifs. The crystal packing is further stabilized by weak inter-molecular N-H⋯O, N-H⋯N, C-H⋯O and π-π [centroid-centroid distance 3.615 (2) Å] inter-actions.

N'-[(1E)-3-Bromo-5-chloro-2-hy-droxy-benzyl-idene]-4-tert-butyl-benzo-hydrazide ethanol monosolvate.

In the title compound, C(18)H(18)BrClN(2)O(2)·C(2)H(6)O, the hy-droxy group forms an intra-molecular O-H⋯N hydrogen bond, which influences the conformation of the Shiff base mol-ecule, where the two aromatic rings form a dihedral angle of 21.67 (8)°. Inter-molecular N-H⋯O and O-H⋯O hydrogen bonds link two Shiff base mol-ecules and two solvent mol-ecules into a centrosymmetric heterotetra-mer. Weak inter-molecular C-H⋯O inter-actions link further tetra-mers related by translation along the a axis into chains.

2-Bromo-4-chloro-6-{(E)-[4-(diethyl-amino)-phen-yl]imino-meth-yl}phenol.

In the title compound, C(17)H(18)BrClN(2)O, the dihedral angle between the aromatic rings is 3.0 (1)°. The methyl-ethanamine group assumes an extended conformation. An intra-molecular O-H⋯N hydrogen bond generates an S(6) ring motif. The crystal packing is stabilized by C-H⋯π and π-π [centroid-centroid distances = 3.691 (1) and 3.632 (1) Å] inter-actions.

2-{[4-(Diethyl-amino)-phen-yl]imino-methyl}-4,6-diiodo-phenol.

In the title compound, C(17)H(18)I(2)N(2)O, the dihedral angle between the aromatic rings is 5.4 (1)°. An intra-molecular O-H⋯N hydrogen bond generates an S(6) ring motif. The crystal packing is stabilized by C-H⋯π and π-π inter-actions [centroid-centroid distance = 3.697 (1) Å].

Cathodic behaviour of stainless steel in coastal Indian seawater: calcareous deposits overwhelm biofilms.

Type-316 stainless steel (SS) was investigated as the cathode in galvanic couples in full-strength seawater from the Gulf of Mannar on the southeast coast of India. Tests were devised to examine the impact of SS cathodes on anode materials with or without the accrual of marine biofilms. Biofilmed SS cathodes significantly enhanced the rate of corrosion of nickel, causing noble shifts in the couple potentials. With mild steel and zinc as the anodes, calcareous deposits developed quite rapidly on the SS cathodes and led to a significant reduction of bacterial numbers. The calcareous deposits also caused substantial reduction of galvanic corrosion rates for mild steel, whereas there was no difference for zinc. The deposits were identified by XRD as essentially carbonates, oxides and hydroxides of calcium and magnesium. Potentiodynamic polarization performed on the actual couples after disconnection and equilibration provided reasonable interpretations of the galvanic corrosion trends. Data from this work suggest that a potential of about -0.70 V vs. saturated calomel electrode (SCE) should provide optimum protection of SS in warmer, full-strength seawater that supports the precipitation of calcareous deposits. The criterion commonly recommended for temperate conditions of lower water temperature and estuarine waters of lower alkalinity is -1.0 V (SCE).

Synthesis, spectroscopic characterization, electrochemical behaviour and antibacterial activity of Ru(III) complexes of 2-[(4-N,N'-dimethylaminophenylimino)-methyl]-4-halophenol.

The reaction of the chelating Schiff base ligands 2-[(4-N,N'-dimethylaminophenylimino)-methyl]-4-X-phenol with [Ru(Cl)(3)(EPh(3))(3)]; (E=P or As); (X=Cl, Br or I) in the benzene afforded new stable ruthenium complexes of the general formula [Ru(Cl)(2)(EPh(3))(2)(L)] (L=anion of bidentate Schiff bases). The newly synthesized complexes were characterized using molar conductivity, spectral (UV-vis, FT-IR and EPR) and electrochemical studies. The molar conductance measurements proved that all these complexes are non-electrolytes. All complexes show strong d-d transition in the visible region. The coordination of imine nitrogen and phenolic oxygen of ligands to ruthenium metal was confirmed with the change in the IR stretching frequency values. The EPR spectral data showed that the complexes are paramagnetic with one unpaired electrons. The redox behaviour of the complexes have been investigated by the cyclic voltammetric technique. All the complexes display an irreversible reduction (Ru(III)/Ru(II)) in the range of -0.826 to -0.971V. In view of the biological activity, the ligands and the complexes were observed that all the complexes showed moderate activity. Also the antibacterial activity of the ligand increased on chelation with metal ion.

The p53 knowledgebase: an integrated information resource for p53 research.

The p53 tumor suppressor protein plays a central role in maintaining genomic integrity by occupying a nodal point in the DNA damage control pathway. Here it integrates a wide variety of signals, responding in one of several ways, that is, cell cycle arrest, senescence or programmed cell death (apoptosis). Mutations in the tumor suppressor gene tp53, which affects the key transcriptional regulatory processes in cell growth and death, occur frequently in cancer and helps explain why p53 has been called the guardian of the genome. There is a vast body of published knowledge on all aspects of p53's role in cancer. To facilitate research, it would be helpful if this information could be collected, curated and updated in a format that is easily accessible to the user community. To this end, we initiated the p53 knowledgebase project (http://p53.bii.a-star.edu.sg). The p53 knowledgebase is a user-friendly web portal incorporating visualization and analysis tools that integrates information from the published literature with other manually curated information to facilitate knowledge discovery. This includes curated information on sequence, structural, mutation, polymorphisms, protein-protein interactions, transcription factors, transcriptional targets, antibodies and post-translational modifications that involve p53. The goal is to collect and maintain all relevant data on p53 and present it in an easily accessible format that will be useful to researchers in the field.