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- 검색키워드
- 저자 : R. P. George (검색결과 19 건)
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George, S.K.,Dipu, M.T.,Mehra, U.R.,Verma, A.K.,Singh, P. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.9
The potential of the spot urine sampling technique as an alternative to performing a total urine collection to predict the microbial nitrogen supply was evaluated in crossbred bulls. In a completely randomized design, 20 growing crossbred bulls were assigned four levels of feed intake (120, 100, 80 and 60% of voluntary dry matter intake) on diets comprised of wheat straw and concentrate mixture (50:50). After three months of experimental feeding, a metabolism trial was conducted for ten days, during which spot urine collections were performed every 6 h post feeding on days 9 and 10. The daily urinary excretion of allantoin (A) and purine derivatives (PD) decreased with the reduction in feed intake while creatinine (C) excretion remained similar in animals fed at different levels. The microbial nitrogen (MN) supply calculated from the PD excreted in total urine (35.08 to 72.08 g/d) was higher at increased levels of feed intake. PD concentration in spot urine samples had poor correlation with feed intake except at 12 h post feeding. A/C ratio and PD/C ratio in spot urine samples remained similar irrespective of sampling time and significantly (p<0.01) correlated with daily urinary PD excretion, digestible organic matter intake and dry matter (DM) intake. However, no significant differences were evident in these ratios among animals fed at levels 120, 100 and 80% of voluntary dry matter intake (VDMI) at different times post feeding. These results suggests that the spot urine sampling technique to predict the microbial protein supply is not suitable for detecting small differences in MN supply and hence, estimation of PD excreted in total urine (mmol/d) is necessary to assess precisely the MN supply in crossbred bulls.
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George, V. Cijo,Kumar, D.R. Naveen,Rajkumar, V.,Suresh, P.K.,Kumar, R. Ashok Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.2
Natural products have been the target for cancer therapy for several years but there is still a dearth of information on potent compounds that may protect normal cells and selectively destroy cancerous cells. The present study was aimed to evaluate the cytotoxic potential of n-butanolic leaf extract of $Annona$ $muricata$ L. on WRL-68 (normal human hepatic cells), MDA-MB-435S (human breast carcinoma cells) and HaCaT (human immortalized keratinocyte cells) lines by XTT assay. Prior to cytotoxicity testing, the extract was subjected to phytochemical screening for detecting the presence of compounds with therapeutic potential. Their relative antioxidant properties were evaluated using the reducing power and $DPPH^*$radical scavenging assay. Since most of the observed chemo-preventive potential invariably correlated with the amount of total phenolics present in the extract, their levels were quantified and identified by HPLC analysis. Correlation studies indicated a strong and significant (P<0.05) positive correlation of phenolic compounds with free radical scavenging potential. The results revealed that the extract was moderately cytotoxic to normal cells with a mean IC50 value of 52.4 ${\mu}g$ when compared with those obtained for cancerous cells (IC50 values of 29.2 ${\mu}g$ for MDA-MB-435S and 30.1 ${\mu}g$ for HaCaT respectively). The study confirms the presence of therapeutically active antineoplastic compounds in the n-butanolic leaf extract of $Annona$ $muricata$. Isolation of the active metabolites from the extract is in prospect.
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Kumar, D.R. Naveen,George, V. Cijo,Suresh, P.K.,Kumar, R. Ashok Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.6
Despite clinical advances in anticancer therapy, there is still a need for novel anticancer metabolites, with higher efficacy and lesser side effects. Oroxylum indicum (L.) Vent. is a small tree of the Bignoniaceae family which is well known for its food and medicinal properties. In present study, the chemopreventive properties of O. indicum hot and cold non-polar extracts (petroleum ether and chloroform) were investigated with MDA-MB-231 (cancer cells) and WRL-68 (non-tumor cells) by XTT assay. All the extracts, and particularly the petroleum ether hot extract (PHO), exhibited significantly (P<0.05) higher cytotoxicity in MDA-MB-231 when compared to WRL-68 cells. PHO was then tested for apoptosis induction in estrogen receptor (ER)-negative (MDA-MB-231) and ER-positive (MCF-7) breast cancer cells by cellular DNA fragmentation ELISA, where it proved more efficient in the MDA-MB-231 cells. Further, when PHO was tested for anti-metastatic potential in a cell migration inhibition assay, it exhibited beneficial effects. Thus non-polar extracts of O. indicum (especially PHO) can effectively target ER-negative breast cancer cells to induce apoptosis, without harming normal cells by cancer-specific cytotoxicity. Hence, it could be considered as an extract with candidate precursors to possibly harness or alleviate ER-negative breast cancer progression even in advanced stages of malignancy.
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Dipu, M.T.,George, S.K.,Singh, P.,Verma, A.K.,Mehra, U.R. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.3
A study was conducted to predict the rumen microbial protein production based on urinary excretion of purine derivatives in buffaloes fed a diet of wheat straw and concentrate (40:60) at four fixed levels of feed intake. (95, 80, 60 and 40% of preliminary voluntary feed intake) following experimental protocol of IAEA (Phase I). The buffaloes were allocated according to a $4{\times}4$ latin square design. The urinary allantoin, uric acid, total PD excretion (mmol/d) in treatments L-95, L-80, L-60 and L-40 was 20.13, 16.00, 12.96 and 9.17; 1.88, 2.12, 2.11 and 2.15; 22.01, 18.12, 15.07 and 11.32, respectively and were significantly (p<0.05) different among treatments except for uric acid. The rate of PD excretion (mmol/d) was positively correlated with the digestible organic matter intake. Variations were observed in PD and creatinine concentration in spot samples collected at 6-hour interval. However, daily PD:Creatinine ratio (PDC index) appears to be a reasonably good predictor of microbial-N supply. The contribution of basal purine excretion to total excretion of purine derivatives (PD) was determined in pre-fasting period followed by a fasting period of 6 d (Phase II). Daily PD and creatinine excretion (mmol/kg $W^{0.75}$) during fasting averaged 0.117 and 0.456 respectively for buffaloes. The excretion rates of PD decreased significantly (p<0.01) during fasting compare to pre-fasting period, the urinary creatinine excretion remained almost similar. Except for creatinine, plasma concentration of target parameters significantly (p<0.01) declined during fasting. Likewise, glomerular filtration rate (GFR) and renal clearance of allantoin and uric acid also decreased. Based on the PD excretion rates during fasting and at different levels of feed intake obtained in this study, a relationship between daily urinary PD excretion (Y-mmol) and microbial purine absorption (X-mmol) was developed for buffaloes as Y = 0.74X+0.117 kg $W^{0.75}$. The microbial N supply (g/kg DOMI) remained statistically similar irrespective of dietary treatment. The results showed that excretion of urinary purine derivatives is positively correlated with the levels of feed intake in Murrah buffaloes and thus, estimation of urinary purine derivatives and PDC index could be used to determine microbial nitrogen supply when there is large variation in level of feed intake.
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Evaluation and Redesign of the Inverted Decoupler: Open and Closedloop Approaches
Anna Paula V. de A. Aguiar,George Acioli Júnior,Péricles R. Barros 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.6
The inverted decoupler is usually designed from estimated process models. These models are usually of reduced order, so that effective decoupling is not always achieved. The redesign of decouplers is a subject that received little attention in literature. In this paper, the methodology for decoupler evaluation and redesign in openloop is reviewed. In addition, a new closed-loop evaluation and redesign methodology is presented. This is the main contribution of this paper. The initial decoupler is evaluated by applying a relay-based excitation signal to the decoupled process. If necessary, the decoupler is redesigned to obtain an effective decoupling at some frequencies of interest. Simulation results is used to illustrate the methodology.
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A Semiconducting Organic Radical Cationic Host–Guest Complex
Fahrenbach, Albert C.,Sampath, Srinivasan,Late, Dattatray J.,Barnes, Jonathan C.,Kleinman, Samuel L.,Valley, Nicholas,Hartlieb, Karel J.,Liu, Zhichang,Dravid, Vinayak P.,Schatz, George C.,Van Duyne, R American Chemical Society 2012 ACS NANO Vol.6 No.11
<P>The self-assembly and solid-state semiconducting properties of single crystals of a trisradical tricationic complex composed of the diradical dicationic cyclobis(paraquat-<I>p</I>-phenylene) (CBPQT<SUP>2(•+)</SUP>) ring and methyl viologen radical cation (MV<SUP>•+</SUP>) are reported. An organic field effect transistor incorporating single crystals of the CBPQT<SUP>2(•+)</SUP>⊂MV<SUP>•+</SUP> complex was constructed using lithographic techniques on a silicon substrate and shown to exhibit <I>p</I>-type semiconductivity with a mobility of 0.05 cm<SUP>2</SUP> V<SUP>–1</SUP> s<SUP>–1</SUP>. The morphology of the crystals on the silicon substrate was characterized using scanning electron microscopy which revealed that the complexes self-assemble into “molecular wires” observable by the naked-eye as millimeter long crystalline needles. The nature of the recognition processes driving this self-assembly, radical–radical interactions between bipyridinium radical cations (BIPY<SUP>•+</SUP>), was further investigated by resonance Raman spectroscopy in conjunction with theoretical investigations of the vibrational modes, and was supported by X-ray structural analyses of the complex and its free components in both their radical cationic and dicationic redox states. These spectroscopic investigations demonstrate that the bond order of the BIPY<SUP>•+</SUP> radical cationic units of host and guest components is not changed upon complexation, an observation which relates to its conductivity in the solid-state. We envision the modularity inherent in this kind of host–guest complexation could be harnessed to construct a library of custom-made electronic organic materials tailored to fit the specific needs of a given electronic application.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2012/ancac3.2012.6.issue-11/nn303553z/production/images/medium/nn-2012-03553z_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn303553z'>ACS Electronic Supporting Info</A></P>
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George, V. Cijo,Kumar, D.R. Naveen,Suresh, P.K.,Kumar, R. Ashok Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5
Oleanolic acid (OA) is a naturally occurring triterpenoid in food materials and is a component of the leaves and roots of Olea europaea, Viscum album L., Aralia chinensis L. and more than 120 other plant species. There are several reports validating its antitumor activity against different cancer cells apart from its hepatoprotective activity. However, antitumor activity against skin cancer has not beed studied well thus far. Hence the present study of effects of OA against HaCaT (immortalized keratinocyte) cells - a cell-based epithelial model system for toxicity/ethnopharmacology-based studies - was conducted. Radical scavenging activity ($DPPH{\cdot}$) and FRAP were determined spectrophotometrically. Proliferation was assessed by XTT assay at 24, 48 and 72 hrs with exposure to various concentrations (12.5-200 ${\mu}M$) of OA. Apoptotic induction potential of OA was demonstrated using a cellular DNA fragmentation ELISA method. Morphological studies were also carried out to elucidate its antitumor potential. The results revealed that OA induces apoptosis by altering cellular morphology as well as DNA integrity in HaCaT cells in a dose-dependent manner, with comparatively low cytotoxicity. The moderate toxicity observed in HaCaT cells, with induction of apoptosis, possibly suggests greater involvement of programmed-cell death-mediated mechanisms. We conclude that OA has relatively low toxicity and has the potential to induce apoptosis in HaCaT cells and hence provides a substantial and sound scientific basis for further validation studies.
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George Anns,Mohan P Remya,Aiswarya P.A.,Rajalakshmi C.,Ipe Thomas Vibin,Joseph Cyriac,Biju P.R. 한국물리학회 2022 Current Applied Physics Vol.39 No.-
Over the past few years, extensive research has been focused on the development of rare-earth-free phosphors to achieve energy-efficient and cost-effective WLEDs with high luminous efficiencies for solid-state lighting applications. Herein, we report a novel rare-earth-free self-activated blue phosphor Ca2Sb2O7, synthesized by solidstate reaction method. The electronic structure and bandgap of the material were determined by the density functional theory (DFT + U) method using Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional. The prepared phosphor could be effectively excited in the range 280–370 nm resulting in a broad blue emission band, owing to the Sb5+ → O2- transition in the (SbO6)7- group. The CIE chromaticity coordinates were found to be (0.144, 0.097) indicating intense blue emission with high color purity of 89%. Also, the prepared phosphor has good thermal stability and an internal quantum efficiency of 24%. All these results indicate that self-activated Ca2Sb2O7 could be a potential blue phosphor for lighting and display devices.
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