Eye shape and retinal shape, and their relation to peripheral refraction

Purpose: We provide an account of the relationships between eye shape, retinal shape and peripheral refraction. Recent findings: We discuss how eye and retinal shapes may be described as conicoids, and we describe an axis and section reference system for determining shapes. Explanations are given of how patterns of retinal expansion during the development of myopia may contribute to changing patterns of peripheral refraction, and how pre-existing retinal shape might contribute to the development of myopia. Direct and indirect techniques for determining eye and retinal shape are described, and results are discussed. There is reasonable consistency in the literature of eye length increasing at a greater rate than height and width as the degree of myopia increases, so that eyes may be described as changing from oblate/spherical shapes to prolate shapes. However, one study indicates that the retina itself, while showing the same trend, remains oblate in shape for most eyes (discounting high myopia). Eye shape and retinal shape are not the same and merely describing an eye shape as being prolate or oblate is insufficient without some understanding of the parameters contributing to this; in myopia a prolate eye shape is likely to involve both a steepening retina near the posterior pole combined with a flattening (or a reduction in steepening compared with an emmetrope) away from the pole

Nickel(II) complex based on bis-(1-(pyridin-2-yl-methyl)-benzimidazol-2-yl-methyl) ether and its utilization in the oxidation of 2-amino-4-tert-butylphenol

A mononuclear nickel(II) complex [Ni(L)2].(NO3)2.H2O is synthesized utilizing a bis-benzimidazolyl ligand (L = bis-(1-(pyridin-2-yl-methyl)-benzimidazol-2-yl-methyl)ether) and characterized by single-crystal X-ray diffraction, elemental analysis, UV-vis and IR spectroscopy. Ni(II) complex crystallizes in the tetragonal system with space group I41/a and appears to be propeller-shaped when viewed along the c-axis. The [Ni(L)2].(NO3)2 complex has been utilized for the oxidation for 2-amino-4-tert-butylphenol to 4-tert-butyl-o-benzoquinone in the presence of hydrogen peroxide and the average rate of reaction is calculated to be 63×10–7 M min–1. The presence of externally added acetate ion tends to inhibit the rate of reaction

The nucleon form-factors of the energy momentum tensor in the Skyrme model

The nucleon form factors of the energy-momentum tensor are studied in the large-Nc limit in the framework of the Skyrme model.Comment: 19 pages, 11 Figures, 2 Tables; correction in footnote 2, extension in App.D, some reformulations, references added, results and conclusions unchange

NADPH oxidase mediates microtubule alterations and diaphragm dysfunction in dystrophic mice

Skeletal muscle from mdx mice is characterized by increased Nox2 ROS, altered microtubule network, increased muscle stiffness, and decreased muscle/respiratory function. While microtubule de-tyrosination has been suggested to increase stiffness and Nox2 ROS production in isolated single myofibers, its role in altering tissue stiffness and muscle function has not been established. Because Nox2 ROS production is upregulated prior to microtubule network alterations and ROS affect microtubule formation, we investigated the role of Nox2 ROS in diaphragm tissue microtubule organization, stiffness and muscle/respiratory function. Eliminating Nox2 ROS prevents microtubule disorganization and reduces fibrosis and muscle stiffness in mdx diaphragm. Fibrosis accounts for the majority of variance in diaphragm stiffness and decreased function, implicating altered extracellular matrix and not microtubule de-tyrosination as a modulator of diaphragm tissue function. Ultimately, inhibiting Nox2 ROS production increased force and respiratory function in dystrophic diaphragm, establishing Nox2 as a potential therapeutic target in Duchenne muscular dystrophy

Interaction of catechin with an iron(III) bis-benzimidazole diamide complex

1703-1708Bis-benzimidazole diamide ligand, 3,3'-thiobis-(N-((1H-benzo[d]imidazol-2-yl)methyl) propanamide [GBTPA = L] has been synthesized and utilized to prepare new Fe(III) complexes with exogenous anionic ligands, Cl¯and NO3­¯. The complexes have been characterized by IR, UV-visible, cyclic voltammetry, EPR and mass spectrometry. Low temperature EPR spectra are characteristic of a rhombic complex undergoing an axial distortion. Redox chemistry of catechin and iron(III) chloride complex in dimethyl sulfoxide, shows that catechin binds with Fe(III) complex leading to a considerable loss of antioxidant activity

Synthesis, spectral and electrochemical studies on Fe (III) and Mn (II) complexes with a tridentate ligand carrying pendant benzimidazolyl groups

548-550Mononuclear iron (III) and manganese (II) complexes with stoichiometry [Fe(BBES)X3].nH2O and [Mn(BBES)X2].nH2O have been synthesized and characterized utilizing a tridentate ligand, 1,5-bis (benzimidazol-2-yl)-3-thiapentane (BBES) with anionic ligands like Clˉ, NO3ˉ, HCOOˉ and NCSˉ. Mossbauer data for Fe(III) complexes indicate that the isomer shift values lie in the range typically observed for high spin Fe(III) complexes while slightly large quadrupole splitting parameter indicate a rhombically distorted Fe(III) centre. Cyclic voltammetric studies for Fe(III) complexes indicate that binding of HCOOˉ anion stabilizes the Fe(III) centre whereas NO3ˉ destabilizes it. A strong EPR signal centered at g≈ 2 for Mn (II) complexes prove that non-cubic crystalline electric fields are weak. Zero field splitting parameter D has also been calculated

Synthesis and characterization of iron(III) complexes with N, N' -bis- (2-phenylbenzimidazolyl)methane

55-56The potentially bidentate ligand, N, N'-bis(2-phenylbenzimidazolyl)methane(BPBM) has been used to synthesize iron(III) complexes. 1H NMR spectra showed both upfield and downfield shifted peaks for ligand protons. The Mossbauer spectral data reveal the presence of high spin ferric ion and lower value of isomer shift indicates substantial covalency in Fe(III) ligand bond. The present Fe(lll) complexes appear to activate the oxidation of tetramethylphenylenediamine by molecular oxygen

Copper(II) complexes with bis thiazole based ligands: Spectral, cyclic voltammetric and EPR studies

1277-1282A series of complexes with stoichiometry corresponding to [CuLX<span style="font-size:12.5pt; mso-bidi-font-size:5.5pt;font-family:Arial">2] has been synthesised, where L is a potentially tridentate ligand carrying pendant benzothiozolyl groups and X = CIO4- ,Cl-, NO3-, CH3COO- and HCOO-. EPR spectra of the complexes examined as a frozen DMF solution reveal a distorted tetragonal geometry. The visible band energy for these copper(II) complexes is found to fall in the range observed for N2O2 type donor environment, while the plot of the reduction potential versus <span style="font-size: 15.5pt;mso-bidi-font-size:8.5pt">d-d <span style="font-size:15.0pt; mso-bidi-font-size:8.0pt">band energy indicates that increasing covalency leads to a decrease in <span style="font-size: 20.0pt;mso-bidi-font-size:13.0pt;font-family:Arial;mso-fareast-font-family: " times="" new="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="">d<span style="font-size:20.0pt; mso-bidi-font-size:13.0pt;font-family:Arial;mso-fareast-font-family:" times="" new="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa;="" mso-bidi-font-style:italic"="">x<span style="font-size:20.0pt; mso-bidi-font-size:13.0pt;font-family:Arial;mso-fareast-font-family:" times="" new="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa;="" mso-bidi-font-style:italic"="">2<span style="font-size:20.0pt; mso-bidi-font-size:13.0pt;font-family:Arial;mso-fareast-font-family:" times="" new="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa;="" mso-bidi-font-style:italic"="">-y<span style="font-size:20.0pt; mso-bidi-font-size:13.0pt;font-family:Arial;mso-fareast-font-family:" times="" new="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa;="" mso-bidi-font-style:italic"="">2<span style="font-size:15.0pt; mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="">orbital energy and a concomitant anodic shift.</span

Synthesis and characterization of copper (I) and copper (II) complexes with 1,5-bis (benzimidazol-2-yl)-3-thiapentane

256-261Complexes with formula <span style="font-size: 14.0pt;font-family:HiddenHorzOCR;mso-bidi-font-family:HiddenHorzOCR">[Cu(BBES)X2].nH2O have been synthesized where BBES is a tridentate ligand containing bis-benzimidazolyl as pendant coordinating group and X is an exogenous anionic ligand (X = HCOO- , CH3COO- ,Cl-, Br-, NO-3). Solution EPR spectroscopy on these complexes reveals that the ground state in these copper (II) complexes comprises d x2-y2 orbital. Cyclic voltammetric studies reveal that E1/2for Cu(II)/Cu(I) couple shifts cathodically with HCOO- as the anionic ligand, implying that binding of this anion stabilizes the Cu (II) state whereas E<span style="font-size:14.0pt; font-family:Arial;mso-bidi-font-style:italic">1/2 , data for NCS-indicates that this anion destabilizes Cu(II) state. Copper (I) complex has also been synthesised in the presence of hydroquinone which shows a well-resolved NMR spectrum in the range 0-10 ppm.</span

Synthesis, characterization and electrochemical studies of mixed ligand copper (II) complexes with tridentate bis(2-ethylbenzimidazolyl)disulphide

768-771A series of complexes with stoichiometry corresponding to [Cu(L)X2]nH2O and mixed ligand complexes [Cu(L)(B)(ClO4 )] ClO4.nH2O have been synthesised, where L is potentially tridentate ligand, bis(2-ethylbenzimidazolyl) disulphide (DTDPB,(C7H5N2(CH2)2S)2} and X=ClO4- , Cl-, NO3-, HCOO-, benzoate while B = pyridine, bipyridine, phenanthroline, morpholine and triazole. X-band EPR spectra of the above complexes examined as a frozen DMSO solution indicate a distorted tetragonal geometry in solution state. The covalency parameter, α2 has also been evaluated