69 research outputs found
IN VITRO ANTIOXIDANT CAPACITY AND FREE RADICAL SCAVENGING ACTIVITIES OF CARDIOSPERMUM HALICACABUM LINN.
Get PDFObjective: Free radicals and oxidants are produced in the body during normal cellular metabolism and exposure to pollutions and ionizing radiations. They exert beneficial and harmful effects to the human body. Harmful effects of these radicals are destroyed by either antioxidants of our body in situ or antioxidants which are supplied through foods. Hence, the aim of this present study is to assess the antioxidant and free radical scavenging capacity of the easily available edible plant Cardiospermum halicacabum Linn. (Mudakathan keerai).Methods: Antioxidant and free radical scavenging activities of the aerial parts extract of C. halicacabum was determined by 2,2-diphenyl-1- picrylhydrazyl (DPPH) radical scavenging assay, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay, ferrous ion chelating assay, nitric oxide (NO) radical scavenging assay, superoxide radical scavenging assay, hydroxyl radical scavenging assay, and lipid peroxidation assay.Results: Remarkable free radical scavenging potential was observed in the ethanolic extract of C. halicacabum with IC50 values on all tested radicals, namely DPPH (IC50=34.06 μg/ml), ABTS (IC50=21.45 μg/ml), ferrous ion chelating (IC50=19.56 μg/ml), NO (IC50=25.16 μg/ml), superoxide (IC50=35.16 μg/ml), hydroxyl (IC50=28.56 μg/ml), and lipid peroxidation (IC50=33.12 μg/ml). The results revealed that ethanolic extract of C. halicacabum Linn. has significant antioxidant activity.Conclusion: The present study suggested that the aerial part extract of C. halicacabum serves as a good source of natural antioxidants
Synthesis and structural characterization of cyclic aryl ethers.
No full textThe facile preparation of macrocyclic ethers is achieved using S NAr reactions of (dichlorobenzene)CpFe + complexes with various dinucleophiles, followed by photolytic demetallation; X-ray crystallography gives unequivocal structural proof for one of these macrocycles
Status of lipid peroxidation, glutathione, ascorbic acid, vitamin E and antioxidant enzymes in patients with osteoarthritis
No full textCarcinogenicity of monomethylarsonous acid (MMAIII) and sodium arsenate (AsV) and identification of early warning biomarkers.
No full textAlthough inorganic arsenic is classified as a human carcinogen, lack of an appropriate animal model till recently made it difficult to understand the mechanism of its carcinogenicity. The first inorganic arsenic-induced tumour study was reported by Ng et al. (1998) in C57Bl/6J mice exposed to 500 μg/L sodium arsenate in drinking water. Subsequently, Waalkes et al. (2003) demonstrated arsenite as a transplacental carcinogen in C3H mice exposed to 42.5 or 85 mg/L sodium arsenite between the 8th to 18th days of gestation. Recently monomethylarsonous acid (MMAIII), an intermediate metabolite of the arsenic methylation pathway was shown to be more acutely toxic and genotoxic in both in vitro and in vivo studies. However, its carcinogenic effect was unknown. The first aim of the present study is to investigate whether MMAIII was carcinogenic in a mouse model. The second aim was to investigate whether there was a difference between the spontaneous tumour seen in the controls and arsenic induced tumour which occurred in the test. The third aim was to confirm the carcinogenic effects reported by Ng et al. (1998) by exposing mice to three different concentrations of sodium arsenate (AsV) or Monomethylarsonous acid (MMAIII) in drinking water and to establish a dose response relationship for both arsenate and MMAIII in this mouse strain; and finally to investigate if porphyrin profile can be used as an early warning biomarker for chronic arsenic exposure prior to the onset of carcinogenesis. Female C57Bl/6J mice were exposed to drinking water containing AsV (sodium arsenate) or MMAIII (monomethylarsonous acid) at 0,100, 250 and 500 μg/L ad libitum respectively for two years. 24 hrs pooled urine samples were collected every 2 months for urinary arsenic and porphyrin analyses. Dimethylarsinic acid (DMAV) was found to be a major urinary metabolite in both AsV and MMAIII-treated mice. The study confirmed the carcinogenic effects of AsV in this mouse strain and for the first time, demonstrated MMAIII to be similarly carcinogenic. Significant increases in the level of urinary prophyrins were observed in both AsV and MMAIII-treated mice compared to the control group. Histological examination of tumour masses and tumour bearing organs showed lymphoma was the major type of tumour observed in both control and treated groups. Tumours generally occurred 18 months post treatment. Tumour-bearing animals appeared to remain healthy until the terminal stages of the experiment. The increased incidences of lymphomas were dose dependent for both AsV and MMAIII -treated groups. Other types of tumours and multiplicity of tumours also showed a significant dose response relationship in the AsVtreated groups. Mesenteric lymph node lymphoma and metastatic lymphoma in the liver showed significant dose response relationship in MMAIII-treated mice. The incidence of other types of tumours histiocytic sarcoma was higher in both AsV and MMAIII-treated mice compared to the controls. Plasmacytoid lymphomas were observed only in treated mice. Chronic dermatitis and other degenerative skin lesions were seen only in the AsV and MMAIII-treated mice and not in the control. Keratoacanthoma of the skin, epidermoid carcinoma and rhabdomyosarcoma were only seen in the MMAIII treated mice and not in the AsV-treated mice. Immunohistological examination showed the lymphomas to be of B cell origin. Microarray was performed in selected tumour and non-tumour liver tissues from control, 100 and 500 μg/L groups from both AsV and MMAIII-treated animals. Oncogenes, genes involved in cell division and cell proliferation, chemokines, cyclin dependent kinases, tumour necrosis factor genes (TNF), Mitogen activated protein kinase (MAPK) family genes, Signal transducer and activator of transcription (STAT) family genes and DNA damage genes were highly expressed in the MMAIII-treated groups compared to the control group. Genes involved in the Nuclear factor of kappa light chain gene enhancer in B-cells (NFκB) signaling pathway like TNF receptorassociated factor (TRAF), IκBKβ, TRAF family member-associated NF-kappa B activator (TANK) and B-cell leukemia/lymphoma 2 (BCL2) showed more than 32 fold increases in the MMAIII-treated tumours compared to the control tumours. Also inflammatory and B-cell leukaemia and lymphoma genes were expressed in MMAIIItreated tumours only. Genes expressed in the MMAIII-treated tumours showed interesting pathways, the antiapoptotic signaling mediated by the TNF-α induced AKT pathway and prosurvival pathway by TNF-α induced TRAF1 and TRAF2 mediated NFκB activation. The present study is the first low dose chronic study of MMAIII, and both AsV and MMAIII demonstrated to be carcinogenic in C57Bl/6J female mice. Higher incidences of all types of tumours in MMAIII-treated mice and incidences of various types of tumours only in MMAIII-treated groups suggested that MMAIII could be more carcinogenic in vivo than AsV. MMAIII also appeared to have induced a greater variety of genes involved in tumorigenesis compared to AsV. In conclusion, this study supports the contention that the arsenic methylation pathway is not necessarily a detoxification pathway but may in fact in some circumstances enhance the toxicity of the element, and that MMAIII might play a significant role in mammalian arsenic carcinogenicity
Automatic Brain Tumor Tissue Detection based on marker controlled watershed segmentation in MRI images
No full textGaSb Inversion-Mode PMOSFETs With Atomic-Layer-Deposited Al2O3 as Gate Dielectric
Get PDFGaSb inversion-mode PMOSFETs with atomic-layer-deposited (ALD) Al2O3 as gate dielectric are demonstrated. A 0.75-mu m-gate-length device has a maximum drain current of 70 mA/mm, a transconductance of 26 mS/mm, and a hole inversion mobility of 200 cm(2)/V . s. The OFF-state performance is improved by reducing the ALD growth temperature from 300 degrees C to 200 degrees C. The measured interface trap distribution shows a low interface trap density of 2 x 10(12) /cm(2) . eV near the valence band edge. However, it increases to 1 - 4 x 10(13) /cm(2) . eV near the conduction band edge, leading to a drain current on-off ratio of 265 and a subthreshold swing of similar to 600 mV/decade. GaSb, similar to Ge, is a promising channel material for PMOSFETs due to its high bulk hole mobility, high density of states at the valence band edge, and, most importantly, its unique interface trap distribution and trap neutral level alignment
Single Crystalline GeSn On Silicon By Solid Phase Crystallization
No full textSingle crystalline GexSn1-x (GeSn) alloys are promising for electronic and optical applications [1]. GeSn has been predicted to exhibit carrier mobilities exceeding that of Ge [2], which makes this material suitable as channel material for high-speed complementary metal-oxide semiconductor (CMOS) technology [3]. In addition to increased carrier mobility, the GeSn material system is interesting for its optical properties. GeSn exhibits a direct band gap between 0.61 and 0.35 eV for Sn concentrations between 6 and 15 % [4]. This makes it much better suited for optoelectronic applications than Si and Ge, especially at long wavelengths.
Alloying Ge with Sn has several challenges, which hamper the formation of high quality layers. First the limited solubility of Sn in Ge of 0.5 % prohibits the formation of alloys with high Sn content [5,6,7]. Another problem with GeSn epitaxy is the large lattice mismatch of tin with germanium and silicon of 18 % and 23 %, respectively. The mismatch between layer and substrate complicates the formation of high quality layers by introducing lattice defects, stress, roughness, compositional fluctuations etc. Suppressing these effects is critical to obtain high quality layers and high performance devices.
Several growth methods have been used to obtain GeSn layers [8]. Chemical vapor deposition [9,10], molecular beam epitaxy [6], sputtering [7] and pulsed laser deposition [11] have been demonstrated. Solid phase epitaxy of GeSn on Si(001) with a Ge buffer has been tried, however with limited structural quality [12].
We demonstrate single crystalline GeSn layers on Si(111) substrates by solid phase epitaxy (SPE) of amorphous GeSn layers with excellent structural quality. We do not use surfactants, capping layer nor buffer layer. Amorphous GeSn layers are obtained by evaporation of Ge and Sn atoms while exposing the substrate to a N2 gas beam of 1.2 standard cubic centimeters per minute (SCCM) and using a deposition temperature around room temperature. Previously we have demonstrated the influence of an inert gas beam during deposition of amorphous Ge on subsequent solid phase epitaxy [13]. The surface adatom mobility is reduced by the presence of inert molecules, which consequently help to decrease the order of the deposited layer. In-situ reflection high electron diffraction (RHEED) shows a diffuse image without the presence of diffraction spots, indicating that the GeSn layer is amorphous and not poly or single crystalline. XRD ω/2θ scan of the as-deposited layer does not show diffraction of GeSn, confirming that the GeSn does not grow epitaxially with the growth conditions that were applied, see Figure 1 (black, solid line with squares).
Subsequent annealing transforms the amorphous GeSn into a single crystalline layer by solid phase epitaxy. An intense and narrow GeSn(111) diffraction peak is observed, indicating high crystal quality, as observed from ω/2θ XRD scan, see Figure 1 (red, solid line). The (111) crystal planes of the GeSn layer are parallel to the (111) Si surface. The presence of Pendellösung fringes indicates a smooth GeSn surface and interface between GeSn and Si. The crystalline quality has been investigated by XRD, Rutherford backscattering and channeling spectrometry (RBS/C) and transmission electron microscopy (TEM). The Sn content and strain has been determined by XRD reciprocal space mapping (RSM). RBS has been used to confirm the Sn content obtained by XRD RSM analysis. Excellent structural quality is demonstrated for layers with 3.8 % of Sn. The XRD rocking curve FWHM of the (111) GeSn reflection shows a value of 162 arc sec. Strain relaxation of 106.7 % has been measured for 38 nm layers, which makes this method promising for strain engineering. Furthermore the surface and interface are smooth, especially when considering the relaxation of the layers. The surface RMS roughness is smaller than 1 nm as measured by atomic force microscopy (AFM) and X-ray reflectivity (XRR). XRR shows a sharp interface between the silicon substrate and GeSn with a RMS roughness smaller than 1 nm. Finally, we show an increased optical absorption for the GeSn layers in respect with Ge, which is promising for integration of optical devices on silicon substrates.
Fig. 1: Comparison of XRD ω/2θ scans of as-deposited (black, solid line with squares) and crystallized (red, solid line) GeSn on Si(111). An intense and narrow GeSn(111) diffraction peak is observed after annealing, indicating high crystal quality. The presence of fringes indicates a smooth GeSn surface and interface between GeSn and Si.
Acknowledgements
R.R.L acknowledges support as Research Fellow of the Research Foundation – Flanders (FWO).
References
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[13] R. R. Lieten et al., Appl. Phys. Lett. 96, 052109 (2010).sponsorship: R. R. L and S. D. acknowledge support as Research Fellow of the Research Foundation - Flanders ( FWO). The authors acknowledge support from the European Union FP7 Integrated Infrastructure Initiative SPIRIT ( contract N. 227012). (Research Fellow of the Research Foundation - Flanders ( FWO), European Union FP7 Integrated Infrastructure Initiative SPIRIT|227012)status: Publishe
CARDIOSPERMUM HALICACABUM LINN. - A REVIEW
Get PDFÂ Â Before the modern day, medicine and its pharmacopeia of synthetic drugs, there were plants and ancient civilizations knew how to use the plants strategically to treat common ailments and even life-threatening diseases. Natural plant-based remedies are used for the both acute and chronic health problems from treating common colds to control blood pressure and cholesterol. Plant medicines were the most widely used medicines in the world because of their safety and very less or no side effects. In this way, the aim of this review article was to summarize the phytochemical and medicinal information of the readily reachable plant Cardiospermum halicacabum Linn. This is commonly known as Balloon vine extensively dispersed in tropical and subtropical areas of world. The roots, leaves, stem, and seeds of this plant are employed as herbal medication. The phytochemical analysis confirmed that this herb contains flavonoids, terpenoids, tannins, saponin, protein, carbohydrates, glycosides, variety of fatty acids, and volatile esters. Due to the presence of various compounds, this plant has antibacterial, antifungal, antiparasitic, antidiarrheal, anxiolytic, antioxidant, antipyretic, antirheumatic, anticonvulsant, anti-inflammatory, and anticancinogenic activities
Analysis of skewness and kurtosis for ambient air quality monitoring data - Neyveli thermal plants
No full text769-775Air pollution adversely affect biological, physical, and human respiratory systems. Monitoring variations of ambient air quality is therefore essential. Like application of probability analysis in the design of mechanical dust collectors this type of analysis can be applied in other ways in air pollution work. Positively skewed distributions are characteristics of naturally occurring phenomena such as, rain fall intensity, wind force, and stream flow. In air pollution phenomena, a good many data are of this type. Dust fall and atmospheric particulate and gaseous concentrations are typical examples. Knowledge of pollution distribution and direction is important when choosing air sampling station. Keeping this in view the air quality study made in September 1988 is analyzed in respect of sulphur dioxide and suspended particulate matter in the ambient air in the neighbourhood of Neyveli Thermal Power Corporation for finding ideal location of sampling stations
Pesticides in sediments from Queensland irrigation channels and drains
No full textPesticide concentration in sediment from irrigation areas can provide information required to assess exposure and fate of these chemicals in freshwater ecosystems and their Likely impacts to the marine environment. In this study, 103 sediment samples collected from irrigation channels and drains in 11 agricultural areas of Queensland were analysed for a series of past and presently used pesticides including various organochlorines, synthetic pyrethroids, benzoyl ureas, triazines and organophosphates. The most often detected compounds were endosulphans (alpha, beta and/or endosulphan sulphate) which were detectable in 78 of the 103 samples and levels ranged from below the limit of quantification (0.1 ng g(-1) dw) up to 840 ng g(-1) dw. DDT and its metabolites were the second most often detected pesticide investigated (74 of the 103 samples) with concentrations up to 240 ng g(-1) dw of Sigma DDTs. Mean Sigma endosulphan and Sigma DDT concentrations mere 1-2 orders of magnitude higher in sediments from the irrigation areas which are dominated by cotton cultivation compared to those which are dominated by sugarcane cultivation. In contrast to these insecticides, the herbicides diuron, atrazine and ametryn were the compounds which were most often detected in sediments from irrigation drains in sugarcane areas with maximum concentrations in areas of 120, 70 and 130 ng g(-1) dw, respectively. In particular during flood events, when light is limiting, transport of these photosynthesis inhibiting herbicides from the sugarcane cultivation areas to the marine environment may result in additional stress of marine plants. (C) 2000 Elsevier Science Ltd, All rights reserved
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