Eggplant (aubergine; Solanum melongena L.), a member of the nightshade family, is widely consumed... more Eggplant (aubergine; Solanum melongena L.), a member of the nightshade family, is widely consumed as a vegetable. A high incidence of allergic reactions to eggplant appears to be commonly experienced among Indians, presumably due to its high histamine content. Therefore, it appeared interesting to investigate the histamine content of different varieties of eggplant (green and purple round; green and purple slender long) using raw, cooked, and dialyzed extracts. A significant varietal difference in the histamine content of eggplant varieties was observed. Highest amount was present in the green round variety (2.41 mg/100 g fresh weight in raw and 2.07 mg/100 g in cooked extracts). The histamine content of other varieties (in mg/100 g raw) is: green slender long (1.80), purple slender long (1.35), and purple round (0.89). Histamine is stable to heat-processing, since only 11-14% loss was observed upon cooking. Skin prick test (SPT) on non-atopic subjects (without any history of eggplant allergy) using four varieties of raw and cooked eggplant extracts revealed that only subjects with a lower threshold for histamine produce positive results equivalent to that seen between 10-100 microg/mL histamine dihydrochloride. It can be concluded that the amount of histamine present in eggplant does not produce a positive SPT response in a majority of non-atopic subjects, and that a positive response in a few subjects are likely to be misdiagnosed as eggplant allergy.
The present study is aimed to determine the biochemical, mostly protein concentrations, antioxida... more The present study is aimed to determine the biochemical, mostly protein concentrations, antioxidant activities and phytochemical constituents in eight mangrove plant leaves existing in Bhavanapadu creek area, specifically Acanthus ilicifolis L. , Aleropus littoralis L., Avicennia marina L., Ceriops tagal L., Rhizophora mucornata L., Sesuvium portulacastrum L., Suaeda maritima L., Zizania aquatica L. Mangrove plants are more susceptible for oxidative stress and damage due to high contents of salt and minerals inside these plants. Therefore, this study was carried out to explore eight mangrove leaf extracts chiefly for antioxidant and 11977 phytochemicals by well known methods. Results showed that the tested leaf extracts possess significant antioxidant and phytochemical activities along with fine protein content. The conclusion of this study is that the tested leaf extracts can serve as natural antioxidant agents, setting ahead the possibility of employing them for therapeutic purposes.
Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis... more Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis of many respiratory disorders. Cytokines and granulocyte macrophage colony-stimulating factors (GM-CSF) play an important role in chronic inflammation. Activator protein-1 (AP-1) the superfamily of transcription factors is involved in proliferation, differentiation, apoptosis, and transformation including inflammation. Understanding the function and regulation of proinflammatory factors involved in inflammation may provide the novel therapeutic strategies in the treatment of inflammatory diseases. Our aim of the present study is to investigate the pro-inflammatory cytokines and pattern of AP-1 factors expressed during activation of lung adenocarcinoma A549 cells by Phorbol-12-myristate-13-acetate (PMA) and to understand the anti-inflammatory effect of apigenin. A549 cells were treated with and without PMA or apigenin, and the cell viability was assessed by MTT assay. Expressions of infl...
Adherence of target materials or those present on the trajectory of the fired projectile is most ... more Adherence of target materials or those present on the trajectory of the fired projectile is most common in the offences involving the use of firearms. The recovery and identification of such adhering materials from a projectile may identify the origin or intermediary objects while fixing the trajectory. In numerous cytological preparations, black deposits, contaminated debris from the barrel, perforated materials
Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis... more Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis of many respiratory disorders. Cytokines and granulocyte macrophage colony-stimulating factors (GM-CSF) play an important role in chronic inflammation. Activator protein-1 (AP-1) the superfamily of transcription factors is involved in proliferation, differentiation, apoptosis, and transformation including inflammation. Understanding the function and regulation of proinflammatory factors involved in inflammation may provide the novel therapeutic strategies in the treatment of inflammatory diseases. Our aim of the present study is to investigate the pro-inflammatory cytokines and pattern of AP-1 factors expressed during activation of lung adenocarcinoma A549 cells by Phorbol-12-myristate-13-acetate (PMA) and to understand the anti-inflammatory effect of apigenin. A549 cells were treated with and without PMA or apigenin, and the cell viability was assessed by MTT assay. Expressions of inflammatory mediators and different AP-1 factors were analyzed by semi-quantitative RT-PCR. IL-6 protein secreted was analyzed by ELISA, and expressions of IL-1β, c-Jun, and c-Fos proteins were analyzed by Western blotting. Activation of A549 cells by PMA, induced the expression of pro-inflammatory cytokine (IL-1β, IL-2, IL-6, IL-8, and TNF-α) mRNAs and secretion of IL-6 and the expression of specific AP-1 factors (c-Jun, c-Fos, and Fra-1). Treatment of cells with apigenin, significantly inhibited PMA-stimulated mRNA expression of above pro-inflammatory cytokines, AP-1 factors, cyclooxygenase-2, and secretion of IL-6 protein. Results suggested that the AP-1 factors may be involved in inflammation and apigenin has anti-inflammatory effect, which may be useful for therapeutic management of lung inflammatory diseases.
The gas-phase coordination behavior of the [Cr(III)(Salen)]PF(6) complex at the free axial positi... more The gas-phase coordination behavior of the [Cr(III)(Salen)]PF(6) complex at the free axial positions has been studied in the presence of amines as ligands (propylamine and a series of diamines) under electrospray ionization conditions. The [Cr(III)(Salen)](+) complex formed stable five- and six-coordinated complex ions, [Cr(III)(Salen)(L)](+) and [Cr(III)(Salen)(L)(2)](+), respectively, where L = solvent molecule or amine. When diamines were used as ligands, abundant [Cr(III)(Salen)(L)](+) ions were observed in which two axial positions of the [Cr(III)(Salen)](+) species are occupied by the two amino groups of the diamine ligand. The relative abundances of ligated complex ions, fragment ions, and solvent adducts of fragment ions in the ESI mass spectra, were found to depend on the cone voltage used to record the spectrum. The ESI mass spectra of [Cr(III)(Salen)](+) in the presence of diamines as ligands, and experiments on ligand-pickup in the collision cell, clearly demonstrated that the [Cr(III)(Salen)(L)](+) complex ion is stable for 1,2-diaminoethane and 1,3-diaminopropane. The stability of [Cr(III)(Salen)(L)](+) ions gradually decreased from 1,4-diaminobutane to 1,6-diaminohexane, and then showed a slight increase for 1,7-diaminoheptane and 1,8-diaminooctane. The collision-induced dissociation spectra of [Cr(III)(Salen)(L)](+) ions support the above observations.
Dimeric complex ions of the type [M(A-H)A]+, where M=metal ion (Co, Ni, Cu, and Zn) and A=ligand ... more Dimeric complex ions of the type [M(A-H)A]+, where M=metal ion (Co, Ni, Cu, and Zn) and A=ligand (lactic acid, methyl lactate or ethyl lactate), were generated in the gas phase under electrospray ionization conditions. The collision-induced dissociation spectra of [M(A-H)A]+ ions were recorded to study the behaviour of ligand and metal ions in decomposition of these dimeric complex ions. Based on the fragmentation pathways observed for complex ions of lactic acid, it is found that both the carboxylic and hydroxyl groups of lactic acid are involved in the complex formation following displacement of a proton by the metal ion. The dimeric complex ions of Co, Ni, and Zn dissociated to yield similar types of ions, whereas that of Cu behaved differently. The dissociations of Co-, Ni-, and Zn-bound dimeric complexes involved losses of neutral molecules while keeping the oxidation state of the metal ion unchanged. However, elimination of radicals is found in the dissociation of dimeric complex ions of Cu, and the oxidation state of copper is reduced from Cu(II) to Cu(I) in the resulting fragment ions. The deprotonated ligand is involved in the fragmentation pathway of Cu complexes, whereas it is intact in other complexes. The oxidation state of the metal ion, nature of the ligand, and site of attachment to the metal ion are found to control the dissociation of these dimeric complex ions.
Fifteen analogues of benzenepropanamine were synthesized and evaluated for their spermicidal as w... more Fifteen analogues of benzenepropanamine were synthesized and evaluated for their spermicidal as well as microbicidal activities against Trichomonas vaginalis and Candida spp. Several compounds showed appreciable dual activities. Compound 12 exhibited good spermicidal (MEC = 0.1%) along with substantial anticandidal (MIC = 0.05%) activities, while compounds 3 and 6 showed significant microbicidal activities with moderate spermicidal effect. The SAR of these structures is being discussed here in this communication. It is concluded that suitable structural modifications in this class of compounds at 3-amino position may lead to a potent spermicide with associated microbicidal activity.
The complexes of transition-metal ions (M2+, where M = Fe, Co, Ni, Cu, Zn, Cd, and Hg) with 2-ace... more The complexes of transition-metal ions (M2+, where M = Fe, Co, Ni, Cu, Zn, Cd, and Hg) with 2-acetylbenzimidazolethiosemicarbazone (L) are studied under electrospray ionization (ESI) conditions. The ESI mass spectra of Fe and Co complexes showed the complex ions corresponding to [M+2L-2H]+, and those of Ni and Zn complexes showed [M+2L-H]+ ions, wherein the metal/ligand ratio is 1:2 and the oxidation state of the central metal ion is +3 in the case of Fe and Co and +2 in the case of Ni and Zn. The Cd and Cu complexes showed preferentially 1:1 complex ions, i.e., [M+L-H]+ or [M+L+Cl]+, whereas Hg formed both 1:1 and 1:2 complex ions. During formation of the above complex ions one or two ligands are deprotonated after keto-enol tautomerism, depending on the nature and oxidation state of central metal ion. The structures and coordination numbers of the metal ions in the complex ions were studied by their collision-induced dissociation spectra and ion-molecule reactions with acetonitrile or propylamine in the collision cell. Based on these results it is concluded that Fe, Co, Ni and Zn form stable octahedral complexes, whereas tetrahedral or square planar complexes are formed preferentially for other metals. In addition, the Cu complex showed a [2L+2Cu-3H]+ ion with a Cu-Cu bond.
Regiospecific formation of carbanions from a set of geometrical (cis and trans isomers) and five ... more Regiospecific formation of carbanions from a set of geometrical (cis and trans isomers) and five different sets of positional isomers (ortho, meta and para isomers) of aromatic carboxylic acids is reported under negative electrospray ionisation conditions by decarboxylation of the carboxylate anions. The structures of decarboxylated anions, [(M-H)-CO 2 ] S , are studied by ion-molecule reactions with carbon dioxide in the collision cell of a triple quadrupole mass spectrometer. The [(M-H)-CO 2 ] S ions generated from the trans and meta/para isomers react with CO 2 to produce product ions corresponding to the addition of one CO 2 , which confirms the survival of the [(M-H)-CO 2 ] S ions as carbanions. On the other hand, the [(M-H)-CO 2 ] S ions generated from cis and ortho isomers failed to react with CO 2 due to rapid isomerisation of the initially generated carbanion to a aromatic carboxylate/oxide anion, which is unreactive with CO 2 , through a facile intramolecular proton transfer from the proton-containing substituent to the carbanion site. When the experiments were performed at high desolvation temperatures (3008C), instead of 1008C, the relative abundance of [(M-H)-CO 2 ] S ions and the corresponding CO 2 adduct in ion-molecule reaction experiments increased significantly due to minimisation of proton exchange. Quantum chemical calculations on some of the generated isomeric carbanions and their isomerised products due to proton transfer support the selective stability of carbanions.
Twenty-two substituted 7-hydroxycoumarins were studied by negative ion electrospray ionization co... more Twenty-two substituted 7-hydroxycoumarins were studied by negative ion electrospray ionization collision- induced dissociation (CID) mass spectrometry. Fragmentation pathways were also investigated by computation method using the B3LYP density functional theory. In general, the most important fragmentations of the 7- hydroxycoumarin [M - H](-) ions were the elimination of CO(2) and CO which agreed with the calculated energies of the proposed fragmentation reactions. In most cases, methyl group elimination was also favorable. Methyl group elimination occurred in three different ways, the most interesting being hydrogen rearrangement from a neighboring alkyl group to a ring carbon, which led to a benzyl radical formation. In some cases, CH(2)CO elimination was observed as well. Isomeric compounds gave rise to different CID spectra.
Electrospray ionisation mass spectrometry studies and quantum chemical calculations indicate that... more Electrospray ionisation mass spectrometry studies and quantum chemical calculations indicate that bidentate ligation of Li + ion to the diamines leads to symmetric bridging and exhibits contrasting relative affinity orderings compared to that of proton for a,v-diamines.
Common grade high purity alumina (99.99%) powder doped with lanthanum oxide was slip cast, dried ... more Common grade high purity alumina (99.99%) powder doped with lanthanum oxide was slip cast, dried and pressureless sintered to submicrometre grain sized alumina at 1380-1410 1C. Samples that attained 4 96% theoretical density (TD) were subsequently hot isostatically pressed to fully dense alumina having Z99.95% TD. Sintered sub-micrometre alumina samples, ground to 2 mm thickness and polished to 0.5 μm surface finish, displayed 4 82% transmission in the 3-5 μm wavelength range. Samples of 0.5 mm thickness also exhibited 40-60% transmission in the visible wavelength region of 400-900 nm. Lanthanum oxide addition within 0.10 wt% was shown to be favourable for improved transparency in the visible region. The alumina samples also exhibited high Vickers hardness values of 2144+45 kg/mm 2 at 5 kg indentation load.
In order to utilize the psyllium husk a natural polysaccharide for developing new green polymeric... more In order to utilize the psyllium husk a natural polysaccharide for developing new green polymeric materials for specialty applications, we have prepared psyllium and acrylic acid based polymeric networks by using N,N′-methylenebisacrylamide (N,N-MBAAm) as crosslinker. The ...
This paper reports "first cut" of the design of... more This paper reports "first cut" of the design of a distributed and object oriented geographic information system, DO-GIS, under development at I.I.T. Delhi. The paper deals with data model, architecture, query processing and data management in a GIS. Considering that geographical data includes information about spatial reference frame, topological connections and requires maintenance of physically distributed spatial data, we argue
Abstract Incremental lines in tooth cementum can be used as a reliable age marker as compared to ... more Abstract Incremental lines in tooth cementum can be used as a reliable age marker as compared to other morphological or histological traits in the human skeleton. The purpose of this study was to examine the correlation between age and the number of incremental ...
Electron Devices Meeting, 1988. IEDM '88. Technical Digest., International
Plasma-induced damage study has been performed on ultrathin oxides and oxynitrides. Effects of ox... more Plasma-induced damage study has been performed on ultrathin oxides and oxynitrides. Effects of oxide exposure, photoresist and gate dopant activation on the electrical and reliability characteristics were investigated. It was found that the sidewall exposed structures show less degradation in Qbd and trapping compared with fully covered MOSCAP structures after O2 plasma exposure. A model for the damage mechanism was proposed which considers the radiation effect and photo-annealing effect, in addition to the well-known charging effect. Note that the damage induced might be very different in other plasma conditions because the photo-anneal effect is strongly dependent on the plasma condition. These results indicate that plasma damage evaluation using fully-covered capacitors alone cannot be used to predict the actual damages in CMOS integrated circuits. It was also found that photoresist overlayer protects the gate from charging and the induced damages will be reduced by activating th...
Eggplant (aubergine; Solanum melongena L.), a member of the nightshade family, is widely consumed... more Eggplant (aubergine; Solanum melongena L.), a member of the nightshade family, is widely consumed as a vegetable. A high incidence of allergic reactions to eggplant appears to be commonly experienced among Indians, presumably due to its high histamine content. Therefore, it appeared interesting to investigate the histamine content of different varieties of eggplant (green and purple round; green and purple slender long) using raw, cooked, and dialyzed extracts. A significant varietal difference in the histamine content of eggplant varieties was observed. Highest amount was present in the green round variety (2.41 mg/100 g fresh weight in raw and 2.07 mg/100 g in cooked extracts). The histamine content of other varieties (in mg/100 g raw) is: green slender long (1.80), purple slender long (1.35), and purple round (0.89). Histamine is stable to heat-processing, since only 11-14% loss was observed upon cooking. Skin prick test (SPT) on non-atopic subjects (without any history of eggplant allergy) using four varieties of raw and cooked eggplant extracts revealed that only subjects with a lower threshold for histamine produce positive results equivalent to that seen between 10-100 microg/mL histamine dihydrochloride. It can be concluded that the amount of histamine present in eggplant does not produce a positive SPT response in a majority of non-atopic subjects, and that a positive response in a few subjects are likely to be misdiagnosed as eggplant allergy.
The present study is aimed to determine the biochemical, mostly protein concentrations, antioxida... more The present study is aimed to determine the biochemical, mostly protein concentrations, antioxidant activities and phytochemical constituents in eight mangrove plant leaves existing in Bhavanapadu creek area, specifically Acanthus ilicifolis L. , Aleropus littoralis L., Avicennia marina L., Ceriops tagal L., Rhizophora mucornata L., Sesuvium portulacastrum L., Suaeda maritima L., Zizania aquatica L. Mangrove plants are more susceptible for oxidative stress and damage due to high contents of salt and minerals inside these plants. Therefore, this study was carried out to explore eight mangrove leaf extracts chiefly for antioxidant and 11977 phytochemicals by well known methods. Results showed that the tested leaf extracts possess significant antioxidant and phytochemical activities along with fine protein content. The conclusion of this study is that the tested leaf extracts can serve as natural antioxidant agents, setting ahead the possibility of employing them for therapeutic purposes.
Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis... more Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis of many respiratory disorders. Cytokines and granulocyte macrophage colony-stimulating factors (GM-CSF) play an important role in chronic inflammation. Activator protein-1 (AP-1) the superfamily of transcription factors is involved in proliferation, differentiation, apoptosis, and transformation including inflammation. Understanding the function and regulation of proinflammatory factors involved in inflammation may provide the novel therapeutic strategies in the treatment of inflammatory diseases. Our aim of the present study is to investigate the pro-inflammatory cytokines and pattern of AP-1 factors expressed during activation of lung adenocarcinoma A549 cells by Phorbol-12-myristate-13-acetate (PMA) and to understand the anti-inflammatory effect of apigenin. A549 cells were treated with and without PMA or apigenin, and the cell viability was assessed by MTT assay. Expressions of infl...
Adherence of target materials or those present on the trajectory of the fired projectile is most ... more Adherence of target materials or those present on the trajectory of the fired projectile is most common in the offences involving the use of firearms. The recovery and identification of such adhering materials from a projectile may identify the origin or intermediary objects while fixing the trajectory. In numerous cytological preparations, black deposits, contaminated debris from the barrel, perforated materials
Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis... more Acute and chronic alveolar or bronchial inflammation is thought to be central to the pathogenesis of many respiratory disorders. Cytokines and granulocyte macrophage colony-stimulating factors (GM-CSF) play an important role in chronic inflammation. Activator protein-1 (AP-1) the superfamily of transcription factors is involved in proliferation, differentiation, apoptosis, and transformation including inflammation. Understanding the function and regulation of proinflammatory factors involved in inflammation may provide the novel therapeutic strategies in the treatment of inflammatory diseases. Our aim of the present study is to investigate the pro-inflammatory cytokines and pattern of AP-1 factors expressed during activation of lung adenocarcinoma A549 cells by Phorbol-12-myristate-13-acetate (PMA) and to understand the anti-inflammatory effect of apigenin. A549 cells were treated with and without PMA or apigenin, and the cell viability was assessed by MTT assay. Expressions of inflammatory mediators and different AP-1 factors were analyzed by semi-quantitative RT-PCR. IL-6 protein secreted was analyzed by ELISA, and expressions of IL-1β, c-Jun, and c-Fos proteins were analyzed by Western blotting. Activation of A549 cells by PMA, induced the expression of pro-inflammatory cytokine (IL-1β, IL-2, IL-6, IL-8, and TNF-α) mRNAs and secretion of IL-6 and the expression of specific AP-1 factors (c-Jun, c-Fos, and Fra-1). Treatment of cells with apigenin, significantly inhibited PMA-stimulated mRNA expression of above pro-inflammatory cytokines, AP-1 factors, cyclooxygenase-2, and secretion of IL-6 protein. Results suggested that the AP-1 factors may be involved in inflammation and apigenin has anti-inflammatory effect, which may be useful for therapeutic management of lung inflammatory diseases.
The gas-phase coordination behavior of the [Cr(III)(Salen)]PF(6) complex at the free axial positi... more The gas-phase coordination behavior of the [Cr(III)(Salen)]PF(6) complex at the free axial positions has been studied in the presence of amines as ligands (propylamine and a series of diamines) under electrospray ionization conditions. The [Cr(III)(Salen)](+) complex formed stable five- and six-coordinated complex ions, [Cr(III)(Salen)(L)](+) and [Cr(III)(Salen)(L)(2)](+), respectively, where L = solvent molecule or amine. When diamines were used as ligands, abundant [Cr(III)(Salen)(L)](+) ions were observed in which two axial positions of the [Cr(III)(Salen)](+) species are occupied by the two amino groups of the diamine ligand. The relative abundances of ligated complex ions, fragment ions, and solvent adducts of fragment ions in the ESI mass spectra, were found to depend on the cone voltage used to record the spectrum. The ESI mass spectra of [Cr(III)(Salen)](+) in the presence of diamines as ligands, and experiments on ligand-pickup in the collision cell, clearly demonstrated that the [Cr(III)(Salen)(L)](+) complex ion is stable for 1,2-diaminoethane and 1,3-diaminopropane. The stability of [Cr(III)(Salen)(L)](+) ions gradually decreased from 1,4-diaminobutane to 1,6-diaminohexane, and then showed a slight increase for 1,7-diaminoheptane and 1,8-diaminooctane. The collision-induced dissociation spectra of [Cr(III)(Salen)(L)](+) ions support the above observations.
Dimeric complex ions of the type [M(A-H)A]+, where M=metal ion (Co, Ni, Cu, and Zn) and A=ligand ... more Dimeric complex ions of the type [M(A-H)A]+, where M=metal ion (Co, Ni, Cu, and Zn) and A=ligand (lactic acid, methyl lactate or ethyl lactate), were generated in the gas phase under electrospray ionization conditions. The collision-induced dissociation spectra of [M(A-H)A]+ ions were recorded to study the behaviour of ligand and metal ions in decomposition of these dimeric complex ions. Based on the fragmentation pathways observed for complex ions of lactic acid, it is found that both the carboxylic and hydroxyl groups of lactic acid are involved in the complex formation following displacement of a proton by the metal ion. The dimeric complex ions of Co, Ni, and Zn dissociated to yield similar types of ions, whereas that of Cu behaved differently. The dissociations of Co-, Ni-, and Zn-bound dimeric complexes involved losses of neutral molecules while keeping the oxidation state of the metal ion unchanged. However, elimination of radicals is found in the dissociation of dimeric complex ions of Cu, and the oxidation state of copper is reduced from Cu(II) to Cu(I) in the resulting fragment ions. The deprotonated ligand is involved in the fragmentation pathway of Cu complexes, whereas it is intact in other complexes. The oxidation state of the metal ion, nature of the ligand, and site of attachment to the metal ion are found to control the dissociation of these dimeric complex ions.
Fifteen analogues of benzenepropanamine were synthesized and evaluated for their spermicidal as w... more Fifteen analogues of benzenepropanamine were synthesized and evaluated for their spermicidal as well as microbicidal activities against Trichomonas vaginalis and Candida spp. Several compounds showed appreciable dual activities. Compound 12 exhibited good spermicidal (MEC = 0.1%) along with substantial anticandidal (MIC = 0.05%) activities, while compounds 3 and 6 showed significant microbicidal activities with moderate spermicidal effect. The SAR of these structures is being discussed here in this communication. It is concluded that suitable structural modifications in this class of compounds at 3-amino position may lead to a potent spermicide with associated microbicidal activity.
The complexes of transition-metal ions (M2+, where M = Fe, Co, Ni, Cu, Zn, Cd, and Hg) with 2-ace... more The complexes of transition-metal ions (M2+, where M = Fe, Co, Ni, Cu, Zn, Cd, and Hg) with 2-acetylbenzimidazolethiosemicarbazone (L) are studied under electrospray ionization (ESI) conditions. The ESI mass spectra of Fe and Co complexes showed the complex ions corresponding to [M+2L-2H]+, and those of Ni and Zn complexes showed [M+2L-H]+ ions, wherein the metal/ligand ratio is 1:2 and the oxidation state of the central metal ion is +3 in the case of Fe and Co and +2 in the case of Ni and Zn. The Cd and Cu complexes showed preferentially 1:1 complex ions, i.e., [M+L-H]+ or [M+L+Cl]+, whereas Hg formed both 1:1 and 1:2 complex ions. During formation of the above complex ions one or two ligands are deprotonated after keto-enol tautomerism, depending on the nature and oxidation state of central metal ion. The structures and coordination numbers of the metal ions in the complex ions were studied by their collision-induced dissociation spectra and ion-molecule reactions with acetonitrile or propylamine in the collision cell. Based on these results it is concluded that Fe, Co, Ni and Zn form stable octahedral complexes, whereas tetrahedral or square planar complexes are formed preferentially for other metals. In addition, the Cu complex showed a [2L+2Cu-3H]+ ion with a Cu-Cu bond.
Regiospecific formation of carbanions from a set of geometrical (cis and trans isomers) and five ... more Regiospecific formation of carbanions from a set of geometrical (cis and trans isomers) and five different sets of positional isomers (ortho, meta and para isomers) of aromatic carboxylic acids is reported under negative electrospray ionisation conditions by decarboxylation of the carboxylate anions. The structures of decarboxylated anions, [(M-H)-CO 2 ] S , are studied by ion-molecule reactions with carbon dioxide in the collision cell of a triple quadrupole mass spectrometer. The [(M-H)-CO 2 ] S ions generated from the trans and meta/para isomers react with CO 2 to produce product ions corresponding to the addition of one CO 2 , which confirms the survival of the [(M-H)-CO 2 ] S ions as carbanions. On the other hand, the [(M-H)-CO 2 ] S ions generated from cis and ortho isomers failed to react with CO 2 due to rapid isomerisation of the initially generated carbanion to a aromatic carboxylate/oxide anion, which is unreactive with CO 2 , through a facile intramolecular proton transfer from the proton-containing substituent to the carbanion site. When the experiments were performed at high desolvation temperatures (3008C), instead of 1008C, the relative abundance of [(M-H)-CO 2 ] S ions and the corresponding CO 2 adduct in ion-molecule reaction experiments increased significantly due to minimisation of proton exchange. Quantum chemical calculations on some of the generated isomeric carbanions and their isomerised products due to proton transfer support the selective stability of carbanions.
Twenty-two substituted 7-hydroxycoumarins were studied by negative ion electrospray ionization co... more Twenty-two substituted 7-hydroxycoumarins were studied by negative ion electrospray ionization collision- induced dissociation (CID) mass spectrometry. Fragmentation pathways were also investigated by computation method using the B3LYP density functional theory. In general, the most important fragmentations of the 7- hydroxycoumarin [M - H](-) ions were the elimination of CO(2) and CO which agreed with the calculated energies of the proposed fragmentation reactions. In most cases, methyl group elimination was also favorable. Methyl group elimination occurred in three different ways, the most interesting being hydrogen rearrangement from a neighboring alkyl group to a ring carbon, which led to a benzyl radical formation. In some cases, CH(2)CO elimination was observed as well. Isomeric compounds gave rise to different CID spectra.
Electrospray ionisation mass spectrometry studies and quantum chemical calculations indicate that... more Electrospray ionisation mass spectrometry studies and quantum chemical calculations indicate that bidentate ligation of Li + ion to the diamines leads to symmetric bridging and exhibits contrasting relative affinity orderings compared to that of proton for a,v-diamines.
Common grade high purity alumina (99.99%) powder doped with lanthanum oxide was slip cast, dried ... more Common grade high purity alumina (99.99%) powder doped with lanthanum oxide was slip cast, dried and pressureless sintered to submicrometre grain sized alumina at 1380-1410 1C. Samples that attained 4 96% theoretical density (TD) were subsequently hot isostatically pressed to fully dense alumina having Z99.95% TD. Sintered sub-micrometre alumina samples, ground to 2 mm thickness and polished to 0.5 μm surface finish, displayed 4 82% transmission in the 3-5 μm wavelength range. Samples of 0.5 mm thickness also exhibited 40-60% transmission in the visible wavelength region of 400-900 nm. Lanthanum oxide addition within 0.10 wt% was shown to be favourable for improved transparency in the visible region. The alumina samples also exhibited high Vickers hardness values of 2144+45 kg/mm 2 at 5 kg indentation load.
In order to utilize the psyllium husk a natural polysaccharide for developing new green polymeric... more In order to utilize the psyllium husk a natural polysaccharide for developing new green polymeric materials for specialty applications, we have prepared psyllium and acrylic acid based polymeric networks by using N,N′-methylenebisacrylamide (N,N-MBAAm) as crosslinker. The ...
This paper reports "first cut" of the design of... more This paper reports "first cut" of the design of a distributed and object oriented geographic information system, DO-GIS, under development at I.I.T. Delhi. The paper deals with data model, architecture, query processing and data management in a GIS. Considering that geographical data includes information about spatial reference frame, topological connections and requires maintenance of physically distributed spatial data, we argue
Abstract Incremental lines in tooth cementum can be used as a reliable age marker as compared to ... more Abstract Incremental lines in tooth cementum can be used as a reliable age marker as compared to other morphological or histological traits in the human skeleton. The purpose of this study was to examine the correlation between age and the number of incremental ...
Electron Devices Meeting, 1988. IEDM '88. Technical Digest., International
Plasma-induced damage study has been performed on ultrathin oxides and oxynitrides. Effects of ox... more Plasma-induced damage study has been performed on ultrathin oxides and oxynitrides. Effects of oxide exposure, photoresist and gate dopant activation on the electrical and reliability characteristics were investigated. It was found that the sidewall exposed structures show less degradation in Qbd and trapping compared with fully covered MOSCAP structures after O2 plasma exposure. A model for the damage mechanism was proposed which considers the radiation effect and photo-annealing effect, in addition to the well-known charging effect. Note that the damage induced might be very different in other plasma conditions because the photo-anneal effect is strongly dependent on the plasma condition. These results indicate that plasma damage evaluation using fully-covered capacitors alone cannot be used to predict the actual damages in CMOS integrated circuits. It was also found that photoresist overlayer protects the gate from charging and the induced damages will be reduced by activating th...
Uploads
Papers by M.Kiran kumar