10 research outputs found
Comparative study of surgically induced astigmatism in superior versus temporal incision in small incision cataract surgery cases
Background: Location of incision has a significant impact on surgical outcome. It has been reported that temporal incisions induce less astigmatism than superior incisions indicating the importance of incision location. The objective of the present study was to study the effect of surgical induced astigmatism in superior versus temporal incision in small incision cataract surgery cases.Methods: 100 patients of cataract attending to Sarojini Devi eye hospital with the rule and against the rule astigmatism were included in the study. The astigmatic profile and the effect of surgical incision on astigmatism were studied. A prospective study was done in which patients were divided into two groups. MSICS was performed with superiorly located incision in group I and temporally located incision in group II.Results: Out of the total 100 patients undergoing MSICS, 59 patients had ATR, 36 patients had WTR and 5 patients had no astigmatism. Thus the pre-operative astigmatic profile shows that ATR is more common type of astigmatism in this group. Among 50 patients in superior incision group, 18 had pre-operative WTR, 29 had ATR and 3 did not have astigmatism. Postoperatively the no. of patients with WTR decreased to 10, the no. of patients with ATR increased to 35 showing that superior incision flattens vertical meridian and steepens the horizontal meridian causing ATR shift. Among 50 patients in temporal incision group, 18 had pre-operative WTR, 30 had ATR and 2 did not have astigmatism. Post operatively the no of patients with WTR increased to 25, the no of patients with ATR decreased to 20.Conclusions: Placement of incision on steep axis reduces pre-existing astigmatism. Thus in ATR astigmatism it is placed temporally and in WTR astigmatism it is placed superiorly. Thus a simple modification in incision placement can minimize surgically induced astigmatism and reduce pre-existing astigmatism
Photoinduced host-to-guest electron transfer in a self-assembled coordination cage
A [Pd2L4] coordination cage, assembled from electron-rich phenothiazine-based ligands and encapsulating an electron-deficient anthraquinone-based disulfonate guest, is reported. Upon excitation at 400 nm, transient absorption spectroscopy unveils photoinduced electron transfer from the host's chromophores to the guest, as indicated by characteristic spectral features assigned to the oxidized donor and reduced acceptor. The structure of the hostâguest complex was characterized by NMR spectroscopy, mass spectrometry and single-crystal X-ray analysis. Spectroelectrochemical experiments and DFT calculations both agree with the proposed light-induced charge separation. A kinetic analysis of the involved charge transfer channels reveals, besides a guest-independent LMCT path, 44% efficiency for the hostâguest charge transfer (HGCT)
Coordination cage-based emulsifiers: templated formation of metal oxide microcapsules monitored by in situ LC-TEM
Metallo-supramolecular self-assembly has yielded a plethora of discrete nanosystems, many of which show competence in capturing guests and catalyzing chemical reactions. However, the potential of low-molecular bottom-up self-assemblies in the development of structured inorganic materials has rarely been methodically explored so far. Herein, we present a new type of metallo-supramolecular surfactant with the ability to stabilize non-aqueous emulsions for a significant period. The molecular design of the surfactant is based on a heteroleptic coordination cage (CGA-3; CGA=Cage-based Gemini Amphiphile), assembled from two pairs of organic building blocks, grouped around two Pd(II) cations. Shape-complementarity between the differently functionalized components generates discrete amphiphiles with a tailor-made polarity profile, able to stabilize non-aqueous emulsions, such as hexadecane-in-DMSO. These emulsions were used as a medium for the synthesis of spherical metal oxide microcapsules (titanium oxide, zirconium oxide, and niobium oxide) from soluble, water-sensitive alkoxide precursors by allowing a controlled dosage of water to the liquid-liquid phase boundary. Synthesized materials were analyzed by a combination of electron microscopic techniques. In situ liquid cell transmission electron microscopy (LC-TEM) was utilized for the first time to visualize the dynamics of the emulsion-templated formation of hollow inorganic titanium oxide and zirconium oxide microspheres
Multi-Stimuli-Responsive Metallogel Molded from a Pd<sub>2</sub><b>L</b><sub>4</sub>âType Coordination Cage: Selective Removal of Anionic Dyes
A self-assembled binuclear coordination
cage of the Pd<sub>2</sub><b>L</b><sub>4</sub> formulation has
been constructed by complexation of PdÂ(NO<sub>3</sub>)<sub>2</sub> with <i>N</i>,<i>N</i>âČ-bisÂ(3-pyridylmethyl)Ânaphthalenediimide
(<b>L</b>). The cage, i.e., [Pd<sub>2</sub>(<b>L</b>)<sub>4</sub>]Â(NO<sub>3</sub>)<sub>4</sub> (<b>1</b>), displayed
a further self-assembly phenomenon to afford a gel phase, upon dissolution
in either dimethyl sulfoxide or acetonitrileâwater (1:1) followed
by standing at room temperature. It was observed that a synergy among
the metal ion, ligand, counteranion, solvent, and concentration played
a vital role for metallogel formation. The morphology of the metallogel
as observed from microscopy studies revealed the formation of a rare
variety of nanoscale metalâorganic particles. Salient features
of the gel include the thixotropic (mechanoresponsive) nature, in
addition to the reversible chemical-stimuli-responsive behavior. The
presence of naphthalenediimide moieties at the backbone of the cage
and the cationic nature of the cavity of the cage could be exploited
to study the functional aspects of the gel. The porous gel exhibited
the abilities to uptake pyrene as a guest and to selectively remove
anionic dyes from aqueous solutions. The gel could bind representative
anionic dyes like âacid blue 93â and âmethyl
orangeâ in the absence or presence of certain cationic dyes,
making the material suitable for selective dye removal applications
Nonaqueous emulsion polycondensation enabled by a selfÂ-assembled cage-like surfactant
Abstract: Nonaqueous emulsions are crucial for a range of applications based on water-sensitive systems such as controlled polymerizations requiring anhydrous reaction conÂditions and the stabilization of readily hydrolyzable reagents or pharmacologically active components. However, defined molecular surfactants to stabilize such nonaqueous emulsions are scarce. We introduce a self-assembled coordination cage, decorated with cholesterol functionalities, to serve as a molecular surfactant for various oil-in-oil emulsions of immisÂcible organic solvents. While the positively charged cage forms the amphiphile's polar moiety, the non-polar cholesterÂol appendices can bend in a common direction to stabilize the emulsion. Templated by the droplets, polycondensation reactions were carried out to produce microstructured polyurÂethane and polyurea materials of different particle sizes and morphologies. Further, the amphiphilic cage can encapsulate a guest molecule and the resulting host-guest assembly was also examined as a surfactant. In addition, the aggregation behavior of the amphiphilic cage in an aqueous medium was examined
Photoinduced host-to-guest electron transfer in a self-assembled coordination cage
A [PdL] coordination cage, assembled from electron-rich phenothiazine-based ligands and encapsulating an electron-deficient anthraquinone-based disulfonate guest, is reported. Upon excitation at 400 nm, transient absorption spectroscopy unveils photoinduced electron transfer from the host's chromophores to the guest, as indicated by characteristic spectral features assigned to the oxidized donor and reduced acceptor. The structure of the hostâguest complex was characterized by NMR spectroscopy, mass spectrometry and single-crystal X-ray analysis. Spectroelectrochemical experiments and DFT calculations both agree with the proposed light-induced charge separation. A kinetic analysis of the involved charge transfer channels reveals, besides a guest-independent LMCT path, 44% efficiency for the hostâguest charge transfer (HGCT)
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Not AvailableInherently low genetic yield potential and susceptibility to biotic and abiotic stresses contribute to low productivity in sesame. Development of stress resistant varieties coupled with high yield is the viable option to raise the genetic yield ceiling. 35 sesame germplasm accessions obtained from diverse agro-climatic regions of India were screened both under natural field and greenhouse conditions to identify disease reaction to the pathogen Fusarium oxysporum spp. sesami. Pathogen was isolated from infected plants and identified fungus inoculum was used to confirm disease reaction. All the accessions displayed some percent infection rate and none could be described as immune. Accessions NSKMS 260, NSKMS-267, NSKMS-261 and TMV-3 were found to be resistant with infection rates of 13.1, 14.6, 15.1 and 15.7% respectively. Accessions RT-54, TMV-4, and NSKMS-115 were found to be moderately resistant. Rest others were found to be moderately susceptible or susceptible or highly susceptible with infection percent ranging from 44.7% to 94.11%. Of all the susceptible ones, TKG-22 and VRISV-1 showed severe infection percent of about 94.1 and 92.3 respectively. Though all the accessions studied were categorized into various classes based on percent disease infection, statistically there is no significant difference in majority of the accessions except NSKMS accessions 260, 261 and 267 and TMV-3. The accessions identified in the present study may be considered in crop improvement programmes involved in developing wilt resistant varieties, however further efforts need to be concentrated on identifying highly resistant genotypes with the inclusion of vast germplasm in screening procedures.Not Availabl