期刊文献+
共找到113篇文章
< 1 2 6 >
每页显示 20 50 100
Spatial distribution of landslides in response to the geomorphometric constraints in Darma Valley,Kumaun Himalaya
1
作者 Mohd SHAWEZ Vikram GUPTA +1 位作者 Anand Kumar GUPTA Gautam RAWAT 《Journal of Mountain Science》 2025年第1期48-70,共23页
The Kumaun Himalaya is well-known as a geologically and tectonically complex region that amplifies mass wasting processes,particularly landslides.This study attempts to investigate the interplay between landslide dist... The Kumaun Himalaya is well-known as a geologically and tectonically complex region that amplifies mass wasting processes,particularly landslides.This study attempts to investigate the interplay between landslide distribution and the lithotectonic regime of Darma Valley,Kumaun Himalaya.A landslide inventory comprising 295 landslides in the area has been prepared and several morphotectonic proxies such as valley floor width to height ratio(Vf),stream length gradient index(SL),and hypsometric integral(HI)have been used to infer tectonic regime.Morphometric analysis,including basic,linear,aerial,and relief aspects,of 59 fourth-order sub-basins,has been carried out to estimate erosion potential in the study area.The result demonstrates that 46.77%of the landslides lie in very high,20.32%in high,21.29%in medium,and 11.61%in low erosion potential zones respectively.In order to determine the key parameters controlling erosion potential,two multivariate statistical methods namely Principal Component Analysis(PCA)and Agglomerative Hierarchical Clustering(AHC)were utilized.PCA reveals that the Higher Himalayan Zone(HHZ)has the highest erosion potential due to the presence of elongated sub-basins characterized by steep slopes and high relief.The clusters created through AHC exhibit positive PCA values,indicating a robust correlation between PCA and AHC.Furthermore,the landslide density map shows two major landslide hotspots.One of these hotspots lies in the vicinity of highly active Munsiyari Thrust(MT),while the other is in the Pandukeshwar formation within the MT's hanging wall,characterized by a high exhumation rate.High SL and low Vf values along these hotspots further corroborate that the occurrence of landslides in the study area is influenced by tectonic activity.This study,by identifying erosionprone areas and elucidating the implications of tectonic activity on landslide distribution,empowers policymakers and government agencies to develop strategies for hazard assessment and effective landslide risk mitigation,consequently safeguarding lives and communities. 展开更多
关键词 LANDSLIDES Geomorphometric analysis Multivariate statistical analysis Darma valley Kumaun Himalaya
在线阅读 下载PDF
Decoding Subsurface Secondary Mineralisation and its Impact on Cohesive Strength:An Outcome of the Deep Scientific Drilling Program in the Koyna-Warna Seismogenic Region,Western India
2
作者 Halder PIYAL Sharma ANUPAM +1 位作者 Kumar Shukla MATSYENDRA Kumar KAMLESH 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第S01期44-50,共7页
The Koyna-Warna seismogenic region overlying the Deccan volcanic province of Western India has been experiencing the recurrence of earthquakes since 1967 soon after the impoundment of the Koyna Dam.A large number of s... The Koyna-Warna seismogenic region overlying the Deccan volcanic province of Western India has been experiencing the recurrence of earthquakes since 1967 soon after the impoundment of the Koyna Dam.A large number of small to medium-magnitude shallow focus earthquakes(>100,000)have been detected in this intraplate region during the last six decades.In the present study,the core samples recovered from the borehole‘KBH3’drilled upto 1134 m depth in the pre-Deccan granitoids basement rocks of this region have been subjected to mineralogical and geochemical studies. 展开更多
关键词 fluid-rock interaction FAULTS CHLORITE hydrothermal alteration recurring seismicity
在线阅读 下载PDF
Evolution of tectonic landscapes and deformation in the southeast Kumaun and western Nepal Himalaya 被引量:1
3
作者 Khayingshing LUIREI Girish Ch.KOTHYARI +5 位作者 Param K GAUTAM Ambar SOLANKI Atul Kumar PATIDAR Sentisenla JAMIR Anirudh DATTA Tanupriya CHOUDHURY 《Journal of Mountain Science》 SCIE CSCD 2024年第8期2592-2617,共26页
The area of the present investigation’s expanse constitutes the southernmost extent of the southeast Kumaun Himalaya and western Nepal Himalaya.Multidisciplinary approaches have been employed to understand the landfo... The area of the present investigation’s expanse constitutes the southernmost extent of the southeast Kumaun Himalaya and western Nepal Himalaya.Multidisciplinary approaches have been employed to understand the landforms associated with tectonic deformation,through detailed field investigation supplemented by the geodetic,chronological,and morphometric database.The morphogenic expressions of the Main Boundary Thrust(MBT)are reflected in the form of~25 km long E-W trending north dipping fault scarp.The deformation along the strike length of the Himalayan Frontal Thrust(HFT)is noticed in the form of uplifted and incised fill terraces,and strath terraces.The deformation within the fluvial sequences in the study area can be visualized in the form of sheared boulders and pebbles,tilted and faulted terrace deposits.Furthermore,the chronological data of fluvial landforms in the study area suggests two major phases of tectonic deformations that have occurred around 58.7±10.8 ka and 3.88±0.4 ka.The chronology of late-Quaternary landforms advocates that the initial stage of aggradations in the Himalayan foothills commenced around 75.1±0.58 ka.The aggradational landforms resulted from the diverse depositional regime as evident from the nature of the sediment sequences from clasts dominated to thick mud sequences.The rate of deformation in the southeastern Kumaun and western Nepal Himalaya is±7 mm/yr,as per the data obtained from the Persistent Scatterer Interferometric Synthetic Aperture Radar(PSInSAR).The landform deformation pattern,phase of incision and aggradation,frequent occurrence of landslides,and recent past earthquake activity within the wide zone of the HFT,the MBT,and Ramgarh Thrust suggests that the southernmost front of the Kumaun Himalaya is active and has potential for future geohazard.The foothill zone of Himalayan towns are actively growing in terms of population and infrastructural development.Therefore,such intradisciplinary studies for tectonically active regions are needed for future infrastructural development. 展开更多
关键词 MBT HFT Fault trace Quaternary deposits sheared boulders
在线阅读 下载PDF
Therapeutic potential of kakkatin derivatives against hepatocellular carcinoma
4
作者 Sahiba Chahal Vikram Patial 《World Journal of Clinical Oncology》 2025年第3期13-19,共7页
In this article,we commented on the work done by Jiang et al,where they syn-thesized a kakkatin derivative,6-(hept-6-yn-1-yloxy)-3-(4-hydroxyphenyl)-7-me-thoxy-4H-chromen-4-one(HK),and investigated its antitumor activ... In this article,we commented on the work done by Jiang et al,where they syn-thesized a kakkatin derivative,6-(hept-6-yn-1-yloxy)-3-(4-hydroxyphenyl)-7-me-thoxy-4H-chromen-4-one(HK),and investigated its antitumor activities and me-chanism in gastric cancer MGC803 and hepatocellular carcinoma(HCC)SMMC-7721 cells.HK was evaluated for its antitumor activity as compared to kakkatin and cisplatin.This article focused on various risk factors of HCC,the mechanism of HCC progression and molecular targets of the kakkatin derivative,and limi-tations of available treatment options.HCC is a predominant form of primary liver cancer characterized by the accumulation of multiple gene modifications,overexpression of protooncogenes,altered immune microenvironment,and infilt-ration by immune cells.Puerariae flos(PF)has been used in traditional medicine in China,Korea,and Japan for lung clearing,spleen awakening,and relieving alcohol hangovers.PF exerts antitumor activity by inhibiting cancer cell prolif-eration,invasion,and migration.PF induces apoptosis in alcoholic HCC via the estrogen-receptor 1-extracellular signal-regulated kinases 1/2 signaling pathway.Kakkatin isolated from PF is known as a hepatoprotective bioflavonoid.The ka-kkatin derivative,HK,exhibited anticancer activity against HCC cell lines by in-hibiting cell proliferation and upregulating nuclear factor kappa B subunit 1 and phosphodiesterase 3B.However,further preclinical and clinical studies are required to establish its therapeutic potential against HCC. 展开更多
关键词 Hepatocellular carcinoma ANTITUMOR Kakkatin PROTOONCOGENES CISPLATIN
在线阅读 下载PDF
QM/MM Based Study of Electronic Structure of Platinum Dihalides
5
作者 Anil Kumar Soni Swati   Vishnu Kumar Sahu 《Open Journal of Applied Sciences》 2025年第1期305-328,共24页
In this research work, atomic and molecular orbitals based analysis has been made to see electronic structure of platinum halides (platinum dichloride, platinum dibromide, platinum diiodide and platinum difluride). Th... In this research work, atomic and molecular orbitals based analysis has been made to see electronic structure of platinum halides (platinum dichloride, platinum dibromide, platinum diiodide and platinum difluride). The geometry optimization and three dimensional (3D) modeling of the above mentioned species have been made on CAChe pro software. The results show: (i) The involvement of three p atomic orbitals is negligible as their summation values are very low in comparison to d orbital and considerably low with respect to s orbital. (ii) The study well support the Landis concepts of sdn-hybridation (here n = 1) as bond angle and contributions of s-orbital and d-orbital of Pt(II) are maximum with negligible contribution of p-orbitals. (iii) These halides also support the cloud-expanding effect with experimental data and also follow the nephelauxetic effect. The result is in good agreement with experiment results that covalent character increases in the order: PtI2 > PtBr2 > PtCl2 > PtF2. (iv) And thus the study will help to fine tune the existing complexes of these halides. 展开更多
关键词 Platinum Dhalides Mulliken Population Analysis sd-Hybridization Molecular Orbital Diagram
在线阅读 下载PDF
Identification of EST–SSRs and molecular diversity analysis in Mentha piperita 被引量:16
6
作者 Birendra Kumar Umesh Kumar Hemant Kumar Yadav 《The Crop Journal》 SCIE CAS CSCD 2015年第4期335-342,共8页
EST sequences of Mentha piperita available in the public domain(NCBI) were exploited to develop SSR markers. A total of 1316 ESTs were assembled into 155 contigs and 653 singletons and of these, 110 sequences were fou... EST sequences of Mentha piperita available in the public domain(NCBI) were exploited to develop SSR markers. A total of 1316 ESTs were assembled into 155 contigs and 653 singletons and of these, 110 sequences were found to contain 130 SSRs, with a frequency of1 SSR/3.4 kb. Dinucleotide repeat SSRs were most frequent(72.3%) with the AG/CT(43.8%)repeat motif followed by AT/AT(16.2%). Primers were successfully designed for 68SSR-containing sequences(62.0%). The 68 primers amplified 13 accessions of M. piperita and 54 produced clear amplicons of the expected size. Of these 54, 33(61%) were found to be polymorphic among M. piperita accessions, showing from 2 to 4 alleles with an average of2.33 alleles/SSR, and the polymorphic information content(PIC) value varied between 0.13 and 0.51(average 0.25). All the amplified SSRs showed transferability among four different species of Mentha, with a highest in Mentha arvensis(87.0%) and minimum in Mentha citrata(37.0%). The newly developed SSRs markers were found to be useful for diversity analysis, as they successfully differentiated among species and accessions of Mentha. 展开更多
关键词 EST–SSRs GENETIC DIVERSITY MENTHA piperita POLYMORPHIC information content Transferability
在线阅读 下载PDF
Identification and characterization of phenolics and terpenoids from ethanolic extracts of Phyllanthus species by HPLC-ESI-QTOF-MS/MS 被引量:11
7
作者 Sunil Kumar Awantika Singh Brijesh Kumar 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2017年第4期214-222,共9页
Phyllanthus species plants are a rich source of phenolics and widely used due to their medicinal properties. A liquid chromatography–tandem mass spectrometry(LC–MS/MS) method was developed using high-pressure liquid... Phyllanthus species plants are a rich source of phenolics and widely used due to their medicinal properties. A liquid chromatography–tandem mass spectrometry(LC–MS/MS) method was developed using high-pressure liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry(HPLC-ESI-QTOFMS/MS) for the identification and characterization of quercetin, kaempferol, ellagic acid and their derivatives in ethanolic extracts of Phyllanthus species. The chromatographic separation was carried out on Thermo Betasil C_8 column(250 mm×4.5 mm, 5 μm) using 0.1% formic acid in water and 0.1% formic acid in methanol as the mobile phase. The identification of diagnostic fragment ions and optimization of collision energies were carried out using 21 reference standards. Totally 51 compounds were identified which include 21 compounds identified and characterized unambiguously by comparison with their authentic standards and the remaining 30 were tentatively identified and characterized in ethanolic extracts of P. emblica, P. fraternus, P. amarus and P.niruri. 展开更多
关键词 PHYLLANTHUS SPECIES HPLC-ESI-QTOF-MS/MS Phenolics
在线阅读 下载PDF
Review of preventive and constructive measures for coal mine explosions:An Indian perspective 被引量:5
8
作者 Santosh Kumar Ray Asfar Mobin Khan +3 位作者 Niroj Kumar Mohalik Debashish Mishra Somu Mandal Jai Krishna Pandey 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2022年第3期471-485,共15页
Firedamp and coal dust explosion constitute a lion’s share in mine accidents in a global mining scenario.This paper reports a list of mine explosion disasters since last two decades,a critical review of the different... Firedamp and coal dust explosion constitute a lion’s share in mine accidents in a global mining scenario.This paper reports a list of mine explosion disasters since last two decades,a critical review of the different prevention and constructive measures,and its recent development to avoid firedamp and coal dust explosion.Preventive legislation in core coal-producing countries,viz.China,USA,Australia,South Africa,and India related to firedamp and coal dust explosion are critically analysed.Accidents occurred due to explosion after Nationalisation of Coal Mines(1973)in India are listed.Prevention and constructive measures adopted in India are critically analysed with respect to the global mining scenario.Measures like methane credit concept,classification of mines/seams with respect to explosion risk zone,deflagration index;installation of automatic fire warning devices,canopy air curtain technology,explosion-prevention measures,such as fire-retardant materials,inhibitors,extinguishing agent,dust suppressor,and active explosion barrier are discussed in detail to avoid explosion and thereby adhering to zero accident policy due to coal mine explosion. 展开更多
关键词 Firedamp explosion Coal dust explosion Preventive measures Constructive measures LEGISLATION
在线阅读 下载PDF
Functional properties, phenolic constituents and antioxidant potential of industrial apple pomace for utilization as active food ingredient 被引量:8
9
作者 Shalika Ranaa Sakshi Gupta +1 位作者 Ajay Rana Shashi Bhushan 《Food Science and Human Wellness》 SCIE 2015年第4期180-187,共8页
Apple pomace is a waste biomass generated after apple fruit processing.In present investigation,efforts were made to comprehend influence of differently dried pomace on cell wall properties and phenolic profile.Differ... Apple pomace is a waste biomass generated after apple fruit processing.In present investigation,efforts were made to comprehend influence of differently dried pomace on cell wall properties and phenolic profile.Different drying techniques were employed to remove moisture content from fresh apple pomace.Total dietary fiber yield(74%)and array of functional properties such as density,water and oil holding capacity,swelling capacity and glucose dialysis retardation index(36.91%)was found better in freeze dried fraction.The higher total phenolics(5.78±0.08 mg GAE/g dry weight)content was also recorded in freeze dried fraction followed by oven and sun drying.The 50%aqueous acetone was found as more efficient solvent for extraction of phenolic constituents.RP-HPLC analysis has revealed presence of quercetin,phloridzin and phloretin as major phenolics.Thus,it is evident from the results that pomace generated at industrial scale can be utilized as a source of dietary food ingredient. 展开更多
关键词 Dietary fiber DRYING Apple pomace POLYPHENOLS ANTIOXIDANT
在线阅读 下载PDF
Solvent extraction of zinc,manganese,cobalt and nickel from nickel laterite bacterial leach liquor using sodium salts of TOPS-99 and Cyanex 272 被引量:3
10
作者 R.K.MISHRA P.C.ROUT +1 位作者 K.SARANGI K.C.NATHSARMA 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第1期301-309,共9页
The extraction and separation of zinc, manganese, cobalt and nickel from nickel laterite bacteria leach liquor were carried out using sodium salts of TOPS-99 and Cyanex 272 in kerosene. The unwanted metal ions were re... The extraction and separation of zinc, manganese, cobalt and nickel from nickel laterite bacteria leach liquor were carried out using sodium salts of TOPS-99 and Cyanex 272 in kerosene. The unwanted metal ions were removed by precipitation method and solvent extraction was used to extract/separate Zn, Mn, Co and Ni. The nickel laterite leach liquor which was obtained from bioleaching of chromite overburden samples contained 3.72 g/L Fe, 2.08 g/L Al, 0.44 g/L Ni, 0.02 g/L Co, 0.13 g/L Mn, 0.14 g/L Zn and 0.22 g/L Cr. From this leach liquor, 100% Fe, 96.98% Al and 70.42% Cr were removed by precipitation with Ca CO_3 at pH 4.4 followed by precipitation of remaining Al and Cr with 50% ammonia at p H 5.4. After precipitation, the extraction of Zn from the Fe, Al and Cr free leach liquor was carried out with 0.1 mol/L TOPS-99 followed by Mn extraction with 0.04 mol/L Na TOPS-99. The yields of Zn and Mn were 97.77% and 95.63%, respectively. After Mn extraction, cobalt was removed from the leach liquor using 0.0125 mol/L Na Cyanex 272 and finally nickel extraction was carried out using 0.12 mol/L Na TOPS-99 with 99.84% yield. The stripping of loaded organic(LO) phases were achieved with dilute H_2SO_4. 展开更多
关键词 nickel laterite MANGANESE NICKEL TOPS-99 Cyanex 272
在线阅读 下载PDF
Role of hydrazine and hydrogen peroxide in aluminium hydroxide precipitation from sodium aluminate solution 被引量:3
11
作者 N.K.SAHU C.K.SARANGI +4 位作者 B.DASH B.C.TRIPATHY B.K.SATPATHY D.MEYRICK I.N.BHATTACHARYA 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第2期615-621,共7页
Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while ... Aluminium hydroxide precipitation from synthetic sodium aluminate solution was studied in the presence of hydrazine or hydrogen peroxide. The addition of low concentration of hydrazine is found to be effective, while higher amount of hydrogen peroxide is required to generate similar effect. XRD data confirm the product phase to be gibbsitic by nature. The scanning electron micrographs (SEM) show that agglomerated products form in the presence of hydrazine while fine discrete particles are produced with hydrogen peroxide. The probable mechanism of precipitation in the presence of hydrazine and hydrogen peroxide is also discussed. 展开更多
关键词 aluminium hydroxide HYDRAZINE hydrogen peroxide sodium aluminate PRECIPITATION
在线阅读 下载PDF
Determination of blast-induced ground vibration equations for rocks using mechanical and geological properties 被引量:17
12
作者 Ranjan Kumar Deepankar Choudhury Kapilesh Bhargava 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2016年第3期341-349,共9页
In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for... In the recent decades, effects of blast loads on natural and man-made structures have gained considerable attention due to increase in threat from various man-made activities. Site-specific empirical relationships for calculation of blast-induced vibration parameters like peak particle velocity (PPV) and peak particle displacement (PPD) are commonly used for estimation of blast loads in design. However, these relation- ships are not able to consider the variation in rock parameters and uncertainty of in situ conditions. In this paper, a total of 1089 published blast data of various researchers in different rock sites have been collected and used to propose generalized empirical model for PPV by considering the effects of rock parameters like unit weight, rock quality designation (ROD), geological strength index (GSI), and uniaxial compressive strength (UCS). The proposed PPV model has a good correlation coefficient and hence it can be directly used in prediction of blast-induced vibrations in rocks. Standard errors and coefficient of correlations of the predicted blast-induced vibration parameters are obtained with respect to the observed field data. The proposed empirical model for PPV has also been compared with the empirical models available for blast vibrations predictions given by other researchers and found to be in good agreement with specific cases. 展开更多
关键词 Blast loadsEmpirical equationsRock quality designation (RQD)Unit weightPeak particle velocity (PPV)Uniaxial compressive strength (UCS)Geological strength index (GSI)
在线阅读 下载PDF
Detrital zircon U-Pb geochronology of stromatolitic carbonates from the greenstone belts of Dharwar Craton and Cuddapah basin of Peninsular India 被引量:2
13
作者 Arubam C.Khelen C.Manikyamba +3 位作者 Li Tang M.Santosh K.S.V.Subramanyam Th Dhanakumar Singh 《Geoscience Frontiers》 SCIE CAS CSCD 2020年第1期229-242,共14页
Oldest rocks are sparsely distributed within the Dharwar Craton and little is known about their involvement in the sedimentary sequences which are present in the Archean greenstone successions and the Proterozoic Cudd... Oldest rocks are sparsely distributed within the Dharwar Craton and little is known about their involvement in the sedimentary sequences which are present in the Archean greenstone successions and the Proterozoic Cuddapah basin.Stromatolitic carbonates are well preserved in the Neoarchean greenstone belts of Dharwar Craton and Cuddapah Basin of Peninsular India displaying varied morphological and geochemical characteristics.In this study,we report results from U-Pb geochronology and trace element composition of the detrital zircons from stromatolitic carbonates present within the Dharwar Craton and Cuddapah basin to understand the provenance and time of accretion and deposition.The UPb ages of the detrital zircons from the Bhimasamudra and Marikanve stromatolites of the Chitradurga greenstone belt of Dharwar Craton display ages of 3426±26 Ma to 2650±38 Ma whereas the Sandur stromatolites gave an age of 3508±29 Ma to 2926±36 Ma suggesting Paleo-to Neoarchean provenance.The U-Pb detrital zircons of the Tadpatri stromatolites gave an age of 2761±31 Ma to1672±38 Ma suggesting Neoarchean to Mesoproterozoic provenance.The Rare Earth Element(REE)patterns of the studied detrital zircons from Archean Dharwar Craton and Proterozoic Cuddapah basin display depletion in light rare earth elements(LREE)and enrichment in heavy rare earth elements(HREE)with pronounced positive Ce and negative Eu anomalies,typical of magmatic zircons.The trace element composition and their relationship collectively indicate a mixed granitoid and mafic source for both the Dharwar and Cuddapah stromatolites.The 3508±29 Ma age of the detrital zircons support the existence of 3.5 Ga crust in the Western Dharwar Craton.The overall detrital zircon ages(3.5-2.7 Ga)obtained from the stromatolitic carbonates of Archean greenstone belts and Proterozoic Cuddapah basin(2.7-1.6 Ga)collectively reflect on^800-900 Ma duration for the Precambrian stromatolite deposition in the Dharwar Craton. 展开更多
关键词 STROMATOLITES ARCHEAN PROTEROZOIC Dharwar Craton Cuddapah basin Detrital zircons
在线阅读 下载PDF
Analysis of isoquinoline alkaloids from Mahonia leschenaultia and Mahonia napaulensis roots using UHPLC-Orbitrap-MSn and UHPLC-QqQ LIT-MS/MS 被引量:10
14
作者 Awantika Singh Vikas Bajpai +2 位作者 Sunil Kumar Ajay Kumar Singh Rawat Brijesh Kumar 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2017年第2期77-86,共10页
Mahonia leschenaultia(ML) and Mahonia napaulensis(MN) are less known and unexplored medicinal plants of the family Berberidaceae. They are used by the Todas of Nilgiris in their religious and medical practices but... Mahonia leschenaultia(ML) and Mahonia napaulensis(MN) are less known and unexplored medicinal plants of the family Berberidaceae. They are used by the Todas of Nilgiris in their religious and medical practices but chemically less identified. Hence, we decided to do extensive phytochemical analysis to explore the potential of these plant extracts. An ultrahigh performance electrospray tandem mass spectrometry(UHPLC-ESI-MS/MS)method was successfully developed for qualitative analysis of the bioactive components in Mahonia species using Orbitrap Velos Pro mass spectrometer. Sixteen compounds were identified by comparison of their retention times and mass spectra(MS) with authentic standards and reported literature. Multi-stage mass spectra(MS(2-8)) for the identification of protoberberine and aporphine alkaloids showed the sequential expulsion of all the substituents attached with their basic skeleton followed by CO loss. Eight of the identified compounds(berberine, jatrorrhizine, palmatine, magnoflorine, isocorydine, glaucine, tetrahydropalmatine and tetrahydroberberine) were simultaneously determined by another UHPLC-ESI-MS/MS method under the multiple reactions monitoring(MRM) mode quantitatively using triple quadrupole linear ion trap mass spectrometer. The analytical method was validated for 8 bioactive compounds with overall recovery in the range98.5%-103.6%(RSD≤2.2%), precise(RSD≤2.07%) and linear(r≥0.9995) over the concentration range of 0.5-1000 ng/mL and successfully applied in ML and MN roots, which suggests the suitability of the proposed approach for the routine analysis of Mahonia species and their quality control. 展开更多
关键词 Orbitrap-MS QqQLIT-MS Mahonia leschenaultia Mahonia napaulensis Isoquinoline alkaloids
在线阅读 下载PDF
Taste masking of ciprofloxacin by ion-exchange resin and sustain release at gastric-intestinal through interpenetrating polymer network 被引量:2
15
作者 A.Michael Rajesh Shreya A.Bhatt +2 位作者 Harshad Brahmbhatt Pritpal Singh Anand Kiritkumar Mangaldas Popat 《Asian Journal of Pharmaceutical Sciences》 SCIE CAS 2015年第4期331-340,共10页
The aim of the study was to taste mask ciprofloxacin(CP)by using ion-exchange resins(IERs)followed by sustain release of CP by forming interpenetrating polymer network(IPN).IERs based on the copolymerization of acryli... The aim of the study was to taste mask ciprofloxacin(CP)by using ion-exchange resins(IERs)followed by sustain release of CP by forming interpenetrating polymer network(IPN).IERs based on the copolymerization of acrylic acid with different cross linking agents were synthesised.Drug-resin complexes(DRCs)with three different ratios of drug to IERs(1:1,1:2,1:4)were prepared&evaluated for taste masking by following in vivo and in vitro methods.Human volunteers graded ADC 1:4,acrylic acid-divinyl benzene(ADC-3)resin as tasteless.Characterization studies such as FTIR,SEM,DSC,P-XRD differentiated ADC 1:4,from physical mixture(PM 1:4)and confirmed the formation of complex.In vitro drug release of ADC 1:4 showed complete release of CP within 60 min at simulated gastric fluid(SGF)i.e.pH 1.2.IPN beads were prepared with ADC 1:4 by using sodium alginate(AL)and sodium alginate-chitosan(AL-CS)for sustain release of CP at SGF pH and followed by simulated intestinal fluid(SIF i.e.pH 7.4).FTIR spectra confirmed the formation of IPN beads.The release of CP was sustain at SGF pH(<20%)whereas in SIF media it was more(>75%).The kinetic model of IPN beads showed the release of CP was non-Fickian diffusion type. 展开更多
关键词 Ion exchange resins Biopolymers In vitro&in vivo taste masking CIPROFLOXACIN Sustain release Release mechanism and kinetics
在线阅读 下载PDF
Thermo-mechanical properties of mullite–zirconia composites derived from reaction sintering of zircon and sillimanite beach sand: Effect of CaO 被引量:1
16
作者 P.KUMAR M.NATH +1 位作者 A.GHOSH H.S.TRIPATHI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第9期2397-2403,共7页
Mullite–zirconia composites containing 20% zirconia(mass fraction) were prepared by reaction sintering route utilizing Indian coastal zircon flour and sillimanite beach sand. 4%-12% of CaO(mole fraction) with res... Mullite–zirconia composites containing 20% zirconia(mass fraction) were prepared by reaction sintering route utilizing Indian coastal zircon flour and sillimanite beach sand. 4%-12% of CaO(mole fraction) with respect to zirconia was used as additive. The effect of additive on densification, microstructure as well as various mechanical and thermo-mechanical properties was studied. Incorporation of CaO reduced the densification temperature of the composites to 1550 ℃ compared to 1600 ℃(for CaO free samples). CaO formed small amount of liquid phase(calcium aluminosilicate), which facilitated sintering. Average grain size of the composites decreased up to 4% CaO addition, afterwards grain size increased with further addition of CaO. Samples with 4% CaO exhibited ~225 MPa of flexural strength, ~6 MPa·m^1/2 of fracture toughness and significant improvement in thermal shock resistance. CaO stabilized the tetragonal zirconia phase and thus improved the mechanical properties. 展开更多
关键词 reaction sintering mullite-zirconia composites flexural strength refractory
在线阅读 下载PDF
Synthesis and characterization of fibrous nickel hydroxide obtained from spent nickel catalyst 被引量:1
17
作者 Pinak PATNAIK Avijit BISWAL +4 位作者 Bankim Chandra TRIPATHY Sangitarani PRADHAN Barsha DASH Ramasamy SAKTHIVEL T.SUBBAIAH 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第10期2977-2983,共7页
The recovery of nickel from spent nickel catalyst for the preparation of nickel hydroxide was studied. Nickel was extracted from the spent catalyst by acid leaching with 1 mol/L sulfuric acid at 90 ℃. Purified nickel... The recovery of nickel from spent nickel catalyst for the preparation of nickel hydroxide was studied. Nickel was extracted from the spent catalyst by acid leaching with 1 mol/L sulfuric acid at 90 ℃. Purified nickel solution was used in the preparation of nickel hydroxide. Three different methods, namely urea hydrolysis, conventional, and hydrothermal methods, of precipitation using NaOH were employed to get various nickel hydroxides samples named as Ni(OH)E-U, Ni(OH)2-C, and Ni(OH)E-H, respectively. Hydrothermal treatment induced better crystallinity in the Ni(OH)2 compared with conventional method. Both Ni(OH)2-C and Ni(OH)E-H samples have mixed phases of fl-Ni(OH)2 and a*-Ni(OH)E.0.75H20 phases, whereas Ni(OH)2-U has only a*-Ni(OH)2.0.75H20. TEM image of Ni(OH)E-U sample shows rod-like Ni(OH)2 structures. Among all, Ni(OH)2-U shows the best electrochemical activity. 展开更多
关键词 spent nickel catalyst fibrous nickel hydroxide RECOVERY
在线阅读 下载PDF
Rapid screening and distribution of bioactive compounds in different parts of Berberis petiolaris using direct analysis in real time mass spectrometry 被引量:2
18
作者 Awantika Singh Vikas Bajpai +2 位作者 Mukesh Srivastava Kamal Ram Arya Brijesh Kumar 《Journal of Pharmaceutical Analysis》 SCIE CAS 2015年第5期332-335,共4页
Berberis petiolaris Wall. ex G. Don, an unexplored medicinal plant belonging to the family Berberidaceae, is a large deciduous shrub found in Western Himalaya between 1800-3000 m. Chemical profiling of fruit, leaf, ro... Berberis petiolaris Wall. ex G. Don, an unexplored medicinal plant belonging to the family Berberidaceae, is a large deciduous shrub found in Western Himalaya between 1800-3000 m. Chemical profiling of fruit, leaf, root and stem was done by direct analysis in real time mass spectrometry followed by multivariate analysis for discrimination among the plant parts. The bioactive compounds, including magnofiorine, berberine, jatrorrhizine, thalifendine/berberrubine, demethyleneberberine, reticuline, 8-oxoberberine, N-methyltetrahydroberberine, tetrahydropalmatine, tetrahydroberberine and palmatine, were identified by their exact mass measurement and the corresponding molecular formula of each compound. A comparative study of distribution pattern for all these bioactive alkaloids showed qualitative and quantitative variations in different parts of B. petiolaris. Principal component analysis clearly dis- criminated each part of B. petiolaris plant. 展开更多
关键词 Berberis petiolarisAlkaloidsProfilingDART-TOF-MSStatistical analysis
在线阅读 下载PDF
Comparative Study on Conventional Sintering with Microwave Sintering and Vacuum Sintering of Y2O3-Al2O3-ZrO2 Ceramics 被引量:1
19
作者 Mayur Shukla Sumana Ghosh +2 位作者 Nandadulal Dandapat Ashis K. Mandal Vamsi K. Balla 《Journal of Materials Science and Chemical Engineering》 2016年第2期71-78,共8页
The present investigation demonstrated the comparative studies carried out on conventional, microwave and vacuum sintering of alumina added yttria stabilized zirconia (YSZ). The conventional, microwave and vacuum sint... The present investigation demonstrated the comparative studies carried out on conventional, microwave and vacuum sintering of alumina added yttria stabilized zirconia (YSZ). The conventional, microwave and vacuum sintered specimens were characterized by density measurement, XRD, SEM with EDX analysis and hardness evaluation. Microwave sintering was proved to be the best efficient sintering technique with respect to energy and time savings. Enhanced densification was observed for the microwave and vacuum sintered specimens at lower temperatures compared to the conventionally sintered ones. Further, it was observed that the particle size had significant influence on the enhancement of densification. The microwave sintered specimen showed the highest hardness compared to conventional and vacuum sintered specimens. 展开更多
关键词 CERAMICS ZIRCONIA SINTERING Density Microstructure HARDNESS
在线阅读 下载PDF
Effect of contrasting climates on antioxidant and bioactive constituents in five medicinal herbs in Western Himalayas 被引量:1
20
作者 Tarandeep KAUR Rohini BHAT Dhiraj VYAS 《Journal of Mountain Science》 SCIE CSCD 2016年第3期484-492,共9页
To understand the effect of climate change on constitutive antioxidant and biochemical metabolites in Western Himalayas, five medicinal herbs were selected and grown at two altitudes in Jammu(305 m) and Srinagar(1730 ... To understand the effect of climate change on constitutive antioxidant and biochemical metabolites in Western Himalayas, five medicinal herbs were selected and grown at two altitudes in Jammu(305 m) and Srinagar(1730 m) with subtropical and temperate climates, respectively.Significant variations were observed in phenols and flavonoids in Hypericum perforatum L., Matricaria chamomilla L., Thymus vulgaris L., Cynara cardunculus L. and Echinacea purpurea L. growing at two locations. High altitude temperate site show variable(up to 13 fold) increase in their content.Proteins(1.3- 1.8 times), sugars(2.8- 4.1 times) and free amino acid(1.04- 1.22 times) were also higher at Srinagar(1730 m). Within these plants, H.perforatum and M. chamomilla have shown higher accumulation of phenols, xanthophylls and proline even at subtropical environment in Jammu(305 m)suggesting potential for increasing their geographical area. The results demonstrate that changing environmental conditions significantly affect the bioactive constituents, which accumulate as a defence strategy by these temperate plants. Their medicinal significance during climate change scenario has also been discussed. 展开更多
关键词 Medicinal herbs Flavonoids Phenols Glutathione Western Himalayas Climate change
在线阅读 下载PDF
上一页 1 2 6 下一页 到第
使用帮助 返回顶部