Epidemiology of cataract in India: combating plans and strategies

Blindness due to cataract presents an enormous problem in India not only in terms of human morbidity but also in terms of economic loss and social burden. The WHO/NPCB (National Programme for Control of Blindness) survey has shown that there is a backlog of over 22 million blind eyes (12 million blind people) in India, and 80.1% of these are blind due to cataract. The annual incidence of cataract blindness is about 3.8 million. The present annual level of performance is in the order of about 1.6-1.9 million cataract operations. To clear the backlog of cataract cases by the year 2000 and to tackle the rising incidence, 5-6 million cataract operations annually will have to be performed as against the present rate of 1. 7 million per year. India is undertaking a new long-term initiative to expand the capability of cataract surgery and service levels with financial assistance from the World Bank. An important feature of this initiative is the attention given to spread the cataract blindness programme in rural and tribal areas. The second feature is the emphasis placed on modern extracapsular cataract extraction with intra-ocular lens implantation as the preferred surgical technique. Another noteworthy feature is developing institutional capacity and appropriate co-ordination mechanisms for collaboration between the non-government organization and the public sector to expand coverage to the most disadvantaged populations. The fourth and the most important strategy is to carry out intensive campaigns at the state and national levels against cataract blindness in order to substantially increase the demand for cataract services. A country like India has more significance for such a plan in view of the fact that various social, economic and environmental factors contribute to cataract blindness in populations at a much younger age.     

A melanin pigment purified from an epidemic strain of Burkholderia cepacia attenuates monocyte respiratory burst activity by scavenging superoxide anion

The acquisition of Burkholderia cepacia in some cystic fibrosis patients is associated with symptoms of acute pulmonary inflammation that may be life threatening. The ability of lipopolysaccharide (LPS) from B. cepacia to prime a monocyte cell line for enhanced superoxide anion generation was investigated and compared with the priming activities of LPSs from Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Escherichia coli. The human monocyte cell line MonoMac-6 (MM6) was primed overnight with different LPSs (100 ng/ml), and the respiratory burst was triggered by exposure to opsonized zymosan (125 micrograms/ml). Superoxide generation was detected by enhanced chemiluminescence with Lucigenin. B. cepacia LPS was found to prime MM6 cells to produce more superoxide anion than P. aeruginosa or S. maltophilia LPS, and this priming response was CD14 dependent. In addition, the inhibition of respiratory burst responses in monocytes by a bacterial melanin-like pigment purified from an epidemic B. cepacia strain was investigated. The melanin-like pigment was isolated from tyrosine-enriched media on which B. cepacia had been grown and was purified by gel filtration, anion ion-exchange chromatography, and ethanol precipitation. The scavenging potential of the melanin-like pigment for superoxide anion radical (*O2-) generated during the respiratory burst was confirmed with superoxide produced from a cell-free system with xanthine-xanthine oxidase and detected by electron paramagnetic resonance spectroscopy with the spin trap 5-diethoxyphosphoryl-5-methyl-1-pyrroline-n-oxide. The addition of melanin during the LPS priming stage had no effect on the subsequent triggering of the respiratory burst, but melanin inhibited *O2- detection when added at the triggering stage of the respiratory burst. We conclude that melanin-producing B. cepacia may derive protection from the free-radical-scavenging properties of this pigment.     

Nonlinear Eulerian Analysis of Harmonic Generation in Traveling-Wave Tubes

A third-order nonlinear Eulerian hydrodynamic formulation was developed for the analysis of harmonic generation in helix traveling-wave tubes. The analysis was simple and computationally fast compared to Lagrangian analysis, and contrary to the existing belief, the theory could as well demonstrate the saturation behavior of the device. The performance of the theory was also found to be in close agreement with that of the Lagrangian analysis. The theory is expected to be useful as a first-hand design and simulation tool for microwave and millimetric wave traveling-wave tubes.     

1‐Butyl‐3‐methylimidazolium Tetrafluoroborate ([Bmim]BF4) Ionic Liquid: A Novel and Recyclable Reaction Medium for the Synthesis of vic‐Diamines

Aziridines undergo ring opening smoothly with various arylamines in 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([bmim]BF₄) or 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim]PF₆) ionic liquids under mild and neutral conditions to afford the corresponding vicinal‐diamines in excellent yields with high regioselectivity. The recovered activated ionic liquids are recycled for four to five runs with no loss of activity.     

N‐Methylprolinol Catalysed Asymmetric Baylis−Hillman Reaction

N‐methylprolinol is used as a chiral base catalyst for the Baylis–Hillman reaction to obtain the adducts in good yields with moderate to good enantioselectivities in 1,4‐dioxane:water (1 : 1, v/v) under ambient conditions.     

Rhodium Acetate Dimer Immobilized in 1‐Butyl‐3‐methylimidazolium Hexafluorophosphate Ionic Liquid: a Novel and Recyclable Catalytic System for the Cyclopropanation of Alkenes

Alkenes undergo smooth cyclopropanation with ethyl diazoacetate using a catalytic amount of rhodium acetate dimer, Rh₂(OAc)₄, immobilized in the air‐ and moisture‐stable 1‐butyl‐3‐methylimidazolium hexafluorophosphate ionic liquid, [bmim]PF₆, to afford cyclopropanecarboxylates in excellent yields with high trans‐selectivity. The recovery of the catalyst is facilitated by the hydrophobic nature of [bmim]PF₆. The recovered ionic liquid containing Rh₂(OAc)₄ can be reused for three to five subsequent runs with only a gradual decrease in activity.     

Transesterification of β ‐keto esters catalysed by transition metal complexes in a novel heterogeneous way

β‐keto esters have been successfully transesterified with primary, secondary, tertiary, allyl and alkynic alcohols by recyclable Mn(III) salen or vanadyl(IV) acetate catalysts realised while conducting the reaction deliberately for the first time in a novel heterogeneous media to afford good to excellent yields. This revised version was published online in July 2006 with corrections to the Cover Date.     

Steady MHD Casson Ohmic heating and viscous dissipative fluid flow past an infinite vertical porous plate in the presence of Soret,Hall, and ion‐slip current

In the present study, the influence of Hall and ion‐slip current on steady magnetohydrodynamics mixed convective, Ohmic heating, and viscous dissipative Casson fluid flow over an infinite vertical porous plate in the presence of Soret effect and chemical reaction are investigated. The modeling equations are transformed into dimensionless equations and then solved analytically through the multiple regular perturbation law. Computations are performed graphically to analyze the behavior of fluid velocity, temperature, concentration, skin friction, Nusselt number, and Sherwood number on the vertical plate with the difference of emerging physical parameters. This study reflects that the incremental values of Casson fluid parameter and Schmidt number lead to reduction in velocity. However, fluid velocity rises due to enhancement of ion‐slip parameter but an opposite effect is observed in case of Hall parameter. In addition, the Sherwood number declines with enhancing dissimilar estimators of the chemical reaction, Schmidt number, as well as Soret number.