North Eastern Hill University

About: North Eastern Hill University is a education organization based out in Shillong, Meghalaya, India. It is known for research contribution in the topics: Population & Catalysis. The organization has 2318 authors who have published 4476 publications receiving 48894 citations.

Comparison of effectiveness in antitumor activity between flavonoids and polyphenols of the methanolic extract of roots of Potentilla fulgens in breast cancer cells

Abstract: Potentilla fulgens has been used for a long time as folk remedy for a variety of ailments without having information on its pharmacological action. The study was intended to determine the effectiveness in antitumor activity among kaempferol (KMP) as flavonoids, ellagic acid (ELA) as polyphenols and methanolic extract of the root of P. fulgens (PRE) in Ehrlich ascites tumour (EA) and MCF-7 cancer cells. The total phenolic and flavonoid content were found to be 138.8 ± 1.6 mg gallic acid and 401.6 ± 4.6 mg quercetin per 1 gm of the extract, respectively. The extract resulted in increasing in vivo survivality of mice bearing EA cells and loss of cell viability in a dose-dependent manner in MCF-7 cells. This effect may be attributed to apoptotic cell death as confirmed by flow cytometric analysis and PARP1 proteolysis. Such induction of apoptosis was achieved by suppression of inhibitor of the apoptosis protein survivin. It was observed that endogenous level of glutathione was depleted significantly in MCF-7 cells after the treatment with PRE only but not with KMP or ELA. This induction of apoptotic cell death and lowering the level of glutathione are highly desirable mode for an anticancer agent.

Catalytic fixation of atmospheric carbon dioxide by copper(II) complexes of bidentate ligands

Abstract: New copper(II) complexes, [Cu(L1)2(H2O)](ClO4)2, 1 [L1 = 2-pyridin-2-yl-quinoline], [Cu(L2)2(H2O)](ClO4)2, 2 [L2 = 2-pyridin-2-yl-quinoxaline], [Cu(L3)2(H2O)](ClO4)2, 3 [L3 = 6,7-dimethyl-2-pyridin-2-yl-quinoxaline], [Cu(L4)2(H2O)](ClO4)2, 4 [L4 = 4-phenyl-2-pyridin-2-yl-quinoline] and [Cu(L5)2(H2O)](ClO4)2, 5 [L5 = 4-phenyl-2-pyridin-2-yl-quinazoline], were synthesized and characterized as catalysts for selective fixation of atmospheric CO2. The molecular structure of 2 was determined by single-crystal X-ray studies and shown to have an unusual trigonal bipyramid geometry (τ, 0.936) around the copper(II) center, with the coordination of two ligand units and a water molecule. The Cu–Nquin (2.040, 2.048 A) bonds are slightly longer than the Cu–Npyr (1.987 A) bonds but shorter than the Cu–Owater bond (2.117 A). Well-defined Cu(II)/Cu(I) redox potentials of around 0.352 to 0.401 V were observed for 1–5 in acetonitrile. The electronic absorption spectra of 1–5 showed ligand-based transitions at around 208–286 nm with a visible shoulder at around 342–370 nm. The d–d transitions appeared at around 750–800 and 930–955 nm in acetonitrile. The rhombic EPR spectra of 1–5 exhibited three different g values gx, 2.27–2.34; gy, 2.06–2.09; and gz, 1.95–1.98 at 70 K. Atmospheric CO2 was successfully fixed by 1–5 using Et3N as a sacrificial reducing agent, resulting in CO32−-bound complexes of type [Cu(L)CO3(H2O)] that display an absorption band at around 614–673 nm and a νst at 1647 cm−1. This CO32−-bound complex of 1 was crystallized from the reaction mixture and it displayed a distorted square pyramidal geometry (τ, 0.369) around the copper(II) center via the coordination of only one ligand unit, a carbonate group, and water molecules. Furthermore, treatment of the carbonate-bound Cu(II) complexes with one equivalent of H+ under N2 atmosphere resulted in the liberation of bicarbonate (HCO3−) and regenerated the parent complexes. These regenerated catalysts were active enough to fix CO2 in eight repeating cycles without any change in efficiency. The fixation of CO2 possibly occurs via the formation of Cu(I)-species, which is accompanied by the formation of an MLCT band at around 450–500 nm. The rates of Cu(I)-species formation, kobs, were determined and found to be 5.41–10.31 × 10−3 s−1 in the presence of Et3N in acetonitrile at 25 °C. Interestingly, the copper(I)-species of 3 has been successfully crystallized and displayed a distorted tetrahedral geometry through the coordination of two units of ligand L3.

Biofunctional Attributes and Storage Study of Soy Milk Fermented by Lactobacillus rhamnosus and Lactobacillus helveticus.

Abstract: Different soybean products are considered as traditional functional food among the Mongolian population in Northeast India. In the present study, the effect of different flavours (mango, orange, vanilla and white rose), inoculation rates of Lactobacillus rhamnosus K4E (KX950834) and Lactobacillus helveticus K14 (KU644578), and mass fractions of skimmed milk and sugar on the acceptability of soy yoghurts was studied. Physicochemical (pH, titratable acidity) and microbial analyses (total bacterial, total coliform, yeast and mould count) were conducted, and organoleptic (aroma, taste, colour, mouthfeel, texture and overall acceptability) and biofunctional properties (angiotensin-converting enzyme (ACE) inhibitory activity, antioxidant and antimicrobial activities and biotransformation of isoflavones) were evaluated during storage up to 10 days under refrigeration conditions (6-8 °C). Panellists preferred white rose soy yoghurt more than other flavours. The pH was from 5.65 to 4.20, the titratable acidity (expressed as mass fraction of lactic acid) was from 0.33 to 0.51% and total Lactobacillus count ranged from 6.81 to 8.69 log CFU/mL during storage. The ACE inhibitory activity increased from 21.17% on day 0 to 81.03% on day 5, followed by a decrease of the activity after 10 days (38.85%). The antioxidant activity was the highest on day 5 (87%). White rose soy yoghurt had the highest antimicrobial activity against Listeria monocytogenes, followed by Bacillus subtilis, Staphylococcus aureus, Salmonella typhi and Escherichia coli. RP-HPLC analysis showed that after 18 h, the production of soy isoflavone aglycones genistein and daidzein in yoghurt was 87.3 and 58.4%, respectively.

Structural and optical properties of glancing angle deposited In 2 O 3 columnar arrays and Si/In 2 O 3 photodetector

Abstract: Ordered and perpendicular columnar arrays of In2O3 were synthesized on conducting ITO electrode by a simple glancing angle deposition (GLAD) technique. The as-deposited In2O3 columns were investigated by field emission gun-scanning electron microscope (FEG-SEM). The average length and diameter of the columns were estimated ∼400 nm and ∼100 nm, respectively. The morphology of the structure was examined by transmission electron microscopy (TEM). X-ray diffraction (XRD) analysis shows the polycrystalline nature of the sample which was verified by selective area electron diffraction (SAED) analysis. The growth mechanism and optical properties of the columns were also discussed. Optical absorption shows that In2O3 columns have a high band to band transition at ∼3.75 eV. The ultraviolet and green emissions were obtained from the In2O3 columnar arrays. The P-N junction was formed between In2O3 and P-type Si substrate. The GLAD synthesized In2O3 film exhibits low current conduction compared to In2O3 TF. However, the Si/GLAD-In2O3 detector shows ∼1.5 times enhanced photoresponsivity than that of Si/In2O3 TF.

Effect of fire on population dynamics of Mikania micrantha H.B.K. during early succession after slash-and-burn agriculture (jhum) in northeastern India

Abstract: Summary: Resume: Zusammenfassung The population size of Mikania micrantha H.B.K. is considerably enhanced by fire in 2-, 4- and 8-year-old fallows developing after slash-and-burn agriculture (jhum) in northeastern India. The recruitment pattern in burnt and unburnt sites in each fallow differed. Seedling recruitment was restricted only to burnt sites in 2- and 4-year-old fallows, whereas it occurred in both burnt and unburnt sites in an 8-year-old fallow. Sexual reproductive potential of the species was affected by the age of the fallow and by fire in each fallow plot. These results are related to micro-environmental changes in the habitat as a consequence of fire in different fallow plots. Effet du feu sur la dynamique des populations de Mikania micrantha H.B.K. dans un mode de conduite alternatif coupe-brulage dans le nord-est de l'Inde L'importance des populations de Mikania micrantha a ete considerablement augmentee par le feu dans des vieilles jacheres de 2, 4 et 8 ans conduites selon la technique coupe-brulage dans le Nord-Est de l'Inde. Le processus de reprise dans les zones brulees et non brulees a ete different pour chacune des jacheres. La reprise de plantules n'a eu lieu que dans les zones brulees pour les jacheres vieilles de 2 et 4 ans. mais elle est survenue en tout lieu dans la jachere de 8 ans. Le potentiel de reproduction sexuee a ete affectea la fois par l'âge de la jachere et par le feu dans chaque parcelle. Ces resultats sont lies a des changements microenvironnementaux dans l'habitat, consequence du feu dans les differentes parcelles en jachere. Der Einfluss von Feuer auf die Populationsdynamik von Mikania micrantha H.B.K. wahrend der Fruhentwicklung einer Folgevegetation nach Brandhackbau in NO-Indien Die Populationsdichte von Mikania micrantha H.B.K. wird nach Rodung und Abbrennen auf 2, 4 und 8 Jahre altem Brachland durch Feuer betrachtlich erhoht. Auf den einzelnen Brachflachen war die Wiederbesiedelung von abgebrannten und nicht abgebrannten Parzellen verschieden. Die Entwicklung einer Samlingspopulation war auf 2 resp. 4 Jahre altem Brachland auf abgebrannte Flachen beschrankt, wahrend auf 8 Jahre alter Brache sowohl auf abgebrannten als auch nicht abgebrannten Flachen die Entwicklung einer Samlingspopulation stattfand. Die sexuelle Reproduktionskraft der Species wird durch die Dauer der Brache und die Wirkung des Feuers beeinflusst. Diese Ergebnisse stehen in Beziehungzu kleinflachigen Umweltveranderungen im Biotop, als Folge des Feuers und des Alters der Brache.