Subhyaloid Hemorrhage in a Case of Devic’s Disease

A 14‑year‑old boy was admitted for paraplegia, acute urinary retention, and a sudden reduction in the visual acuity of both eyes. Fundus examination revealed bilateral optic neuritis with large subhyaloid hemorrhage in left eye. Cerebrospinal fluid examination showed mild pleocytosis and absence of oligoclonal band. Magnetic resonance imaging (MRI) revealed hyper intensity in T2‑weighted images along the spinal cord. No abnormality was detected in brain MRI. Visual evoked potentials were suggestive of bilateral optic neuropathy. He received intravenous pulse corticosteroids (methyl prednisolone) for 3 days followed by oral prednisolone. There was improvement in both the visual acuity and the systemic manifestations. We diagnosed the case as neuromyelitis optica (NMO) based on the examination and investigation findings. NMO or Devic’s syndrome is an uncommon clinical syndrome associating unilateral or bilateral optic neuritis and transverse myelitis. Subhyaloid hemorrhage, as an ophthalmic feature of NMO, has not been reported till date. We report this case so as to alert the clinician about this unusual presentation of NMO.Keywords: Neuromyelitis optica, optic neuritis, subhyaloid hemorrhage, transverse myeliti

Modeling Barkhausen Noise in Magnetic Glasses with Dipole-Dipole Interactions

Long-ranged dipole-dipole interactions in magnetic glasses give rise to magnetic domains having labyrinthine patterns. Barkhausen Noise is then expected to result from the movement of domain boundaries which is supposed to be modeled by the motion of elastic membranes with random pinning. We propose an atomistic model of such magnetic glasses in which we measure the Barkhausen Noise which indeed results from the movement of domain boundaries. Nevertheless the statistics of the Barkhausen Noise is found in striking disagreement with the expectations in the literature. In fact we find exponential statistics without any power law, stressing the fact that Barkhausen Noise can belong to very different universality classes. In this glassy system the essence of the phenomenon is the ability of spin-carrying particles to move and minimize the energy without any spin flip. A theory is offered in excellent agreement with the measured data without any free parameter.Comment: 5 Pages, 5 Figures, Submitted to EP

Surface embedded enhancement of fluorescence of coumarinyl-azo-imidazolium stabilized gold nanoparticles

316-323<span style="letter-spacing:-.1pt;mso-bidi-font-weight: bold" lang="EN-GB">Coumarinyl-azo-imidazole (CAI-H) undergoes double alkylation to yield 1, 3-dialkyl-2-(coumarinyl-6-azo)imidazolium bromide<span style="mso-bidi-font-weight: bold"> (CAI-(CnH2n+1)2+Br-) of long chain alkyl groups –CnH2n+1 (n = 6, 9, 12, 15, 18) attached to imidazolyl motif. These compounds are characterized by spectroscopic data (FT-IR, UV-vis and 1H NMR). The size of the gold nanoparticles stabilized with tetraoctylammonium bromide (avg size 20.5 nm) is reduced to 2–10 nm upon surface implantation of CAI-(CnH2n+1)2+; these have been characterized by FESEM/TEM. The spectroscopic investigation has established the stability of gold nanoparticles. The fluorescence emissivity of these nanoparticles is enhanced 10–25 folds as compared to free CAI-(CnH2n+1)2+Br–, which may be due to coupling of plasmonic band with emission of fluorescent dye molecules and the reduction of PET (Coumarin*→ Imidazolium) and vibrational relaxation of imidazolium coating on the gold nanoparticles surface. <span style="letter-spacing: -.1pt;mso-bidi-font-weight:bold" lang="EN-GB"> </span

Arylazoimidazole complexes of lead(II)-halide and their photochromism

418-426Lead(II) complexes of 1-alkyl-2-(arylazo)imidazole (Raai-CnH2n+1), [Pb(Raai-CnH2n+1)X2] (X = Cl, Br, I; and Raai-CnH2n+1, R = H, Me and n = 4, 6, 8) have been characterized by UV-vis, IR and 1H-NMR spectroscopy. The coordinated Raai-CnH2n+1 in the complexes undergoes E-to-Z (trans-to-cis) isomerisation about the –N=N– group upon being irradiated with UV light in DMF solution. The rate and quantum yields of E-to-Z photoisomerisation (φE→Z) of the complexes are poorer than the respective free ligand response and are also affected by the nature of halide present (Cl-, Br- and I-). Variation in physicochemical parameters may be correlated with the effective mass of the photochrome. The rate of isomerisation follows the sequence: [Pb(Raai-CnH2n+1)Cl2] nH2n+1)Br2] nH2n+1)I2]. The Z-to-E isomerisation has been carried out at varying temperatures (298–308 K) to determine the activation energy of Z-to-E (cis-to-trans) isomerisation (Ea: 47.09–63.42 kJ mol-1) and the entropy of activation (S : 166.52 to –109.0 J mol-1 K-1) which is a large negative in the complexes. Theoretical calculation supports cleavage of Pb(II)-N(azo) bond followed by the –N=N– rotation in a three-coordinated symmetry rather than the four-coordinated symmetry

Refined Crystal Structure (2.3A° ) of a Double-Headed Winged Bean a-Chymotrypsin Inhibitor and Location of Its Second Reactive Site

The crystal structure of a doubleheaded a-chymotrypsin inhibitor, WCI, from winged bean seeds has now been refined at 2.3A° resolution to an R-factor of 18.7% for 9,897 reflections. The crystals belong to the hexagonal space group P6122 with cell parameters a 5 b 5 61.8A° and c 5 212.8A° . The final model has a good stereochemistry and a root mean square deviation of 0.011A° and 1.14° from ideality for bond length and bond angles, respectively. A total of 109 ordered solvent molecules were localized in the structure. This improved structure at 2.3A° led to an understanding of themechanism of inhibition of the protein against a-chymotrypsin.An analysis of this higher resolution structure also helped us to predict the location of the second reactive site of the protein, about which no previous biochemical information was available. The inhibitor structure is spherical and has twelve antiparallel b-strands with connecting loops arranged in a characteristic b-trefoil fold common to other homologous serine protease inhibitors in the Kunitz (STI) family as well as to some non homologous functionally unrelated proteins. Awide variation in the surface loop regions is seen in the latter ones. Proteins 1999;35:321–331. r 1999Wiley-Liss, Inc

Doubly end-on azido bridged mixed-valence cobalt trinuclear complex: spectral study, VTM, inhibitory effect and antimycobacterial activity on human carcinoma and tuberculosis cells

Doubly end-on azido-bridged mixed-valence trinuclear cobalt complex, [Co3(L)2(N3)6(CH3OH)2] (1) is afforded by employing a potential monoanionic tetradentate-N2O2 Schiff base precursor (2-[{[2-(dimethylamino)ethyl]imino}methyl]-6-methoxyphenol; HL). Single crystal X-ray structure reveals that in 1, the adjacent CoII and CoIII ions are linked by double end-on azido bridges and thus the full molecule is generated by the site symmetry of a crystallographic twofold rotation axis. Complex 1 is subjected on different spectral analysis such as IR, UV&#8212;vis, emission and EPR spectroscopy. On variable temperature magnetic study, we observe that during cooling, the χMT values decrease smoothly until 15 K and then reaches to the value 1.56 cm3 K mol−1 at 2 K. Complex 1 inhibits the cell growth on human lung carcinoma (A549 cells), human colorectal (COLO 205 and HT-29 cells), and human heptacellular (PLC5 cells) carcinoma cells. Complex 1 exhibits anti-mycobacterial activity and considerable efficacy on Mycobacterium tuberculosis H37Rv ATCC 27294 and H37Ra ATCC 25177 strains

Intercatenated Coordination Polymers (ICPs) of Carboxylato Bridged Zn(II)-Isoniazid and Their Electrical Conductivity

Three new coordination polymers (CPs) of coordinated isoniazid (INH) to Zn­(II) with succinic acid (H₂succ), fumaric acid (H₂fum), and terephthalic acid (H₂bdc) as organic linker, [Zn­(INH)­(succ)]_<i>n</i> (<b>1</b>), [Zn­(INH)­(fum)]_<i>n</i> (<b>2</b>), and [Zn­(INH)­(bdc)]_<i>n</i> (<b>3</b>), respectively, have been characterized. The structure determination by the single crystal X-ray diffraction technique shows a ZnN₂O₄ distorted octahedral geometry, and the 1D chain is constituted via the INH and carboxylate coordination along with the hydrogen bonding (N–H···O) which comprises a 2D structure. The CPs, <b>1</b> and <b>2</b>, are isostructural and fabricate supramolecular networks by inclined intercatenation of two 2D layers, while <b>3</b> shows parallel intercatenation. The electrical conductivity and Schottky barrier diode behavior have been established by the charge transport mechanism of the compounds at the quasi-Fermi level state. The analysis indicates that the compound <b>1</b> has the highest mobility (2.53 × 10 ^–10 m² V^–1 s^–1) than <b>2</b> (1.86 × 10^–10 m² V^–1 s^–1) and <b>3</b> (1.89 × 10^–10 m² V^–1 s^–1) and the highest electrical conductivity (2.26 × 10^–4 S m^–1) than the others (1.12 × 10^–4 S m^–1 (<b>2</b>) and 1.25 × 10^–4 S m^–1 (<b>3</b>)). DFT computation of the structural motif of CPs has calculated the band gap (Δ<i>E</i>: 3.93 eV (<b>1</b>), 4.45 eV (<b>2</b>), 4.26 eV (<b>3</b>)), which supports the progression of conductivity

EPR interpretation, magnetism and biological study of a Cu(II) dinuclear complex assisted by a schiff base precursor

A new Cu(II) dinuclear complex, Cu2L2 (1) was afforded employing the potentially pentatentate Schiff base precursor H2L, a refluxed product of o-vanillin and diethylenetriamine in methanol. Complex 1 was systematically characterized by FTIR, UV-Vis, emission and EPR spectrometry. The single crystal X-ray diffraction analysis of 1 reveals that the copper atom exhibits a distorted square planar geometry, comprising two pairs of phenolato-O and imine-N donors from two different H2L ligands. The temperature dependent magnetic interpretation agrees with the existence of weak antiferromagnetic interactions between the bridging dinuclear Cu(II) ions. A considerable body of experimental evidence has been accumulated to elucidate the magneto-structural relationship in this dinuclear Cu(II) complex by DFT computation. Both the ligand and complex 1 exhibit anti-mycobacterial activity and considerable efficacy on M. tuberculosis H37Ra (ATCC 25177) and M. tuberculosis H(37)Rv (ATCC 25618) strains. The practical applicability of the ligand and complex 1 has been examined in living cells (African Monkey Vero Cells). The MTT assay proves the non-toxicity of the probe up to 100 mg mL(-1). A new homometallic dinuclear Cu(II) complex is afforded with a tetradentate Schiff base precursor. EPR interpretation and temperature dependent magnetic studies show that complex 1 has weak antiferromagnetic coupling and DFT computation is governed to explain the magneto-structural correlation