Browsing by Author "A.C. Pandey"

Now showing 1 - 12 of 12

Efficient water soluble nanostructured ZnO grafted O-carboxymethyl chitosan/curcumin-nanocomposite for cancer therapy
(Elsevier Ltd, 2015) Laxmi Upadhyaya; Jay Singh; Vishnu Agarwal; A.C. Pandey; Shiv P. Verma; Parimal Das; R.P. Tewari
The present work deals with the synthesis of efficient water soluble O-carboxymethyl chitosan (O-CMCS) based nanocomposites (NCs) with nanostructured zinc oxide (n-ZnO) by ex-situ grafting method for the delivery of anticancer drug curcumin (Cr). The phase identification, morphology and thermal stability of prepared Cr/O-CMCS/n-ZnO NCs have been investigated by FT-IR, XRD, SEM, TEM and TGA/DTA techniques. The drug entrapment efficiency have found to be 74% and in vitro drug release study performed at 37 °C at pH 4.5 and 7.4 indicated slow and controlled release in the initial phase and sustained in later phase. The MTT assay showed higher and preferential toxicity of the Cr/O-CMCS/n-ZnO NCs against cancer cells (MA104). The cellular uptake study by FACS revealed concentration dependent uptake of the NCs. The utilization of this Cr/O-CMCS/n-ZnO nanoformulation offers an efficient strategy and a novel promising soluble nanomatrix for anticancer therapy and other biomedical applications. © 2015 Elsevier Ltd. All rights reserved.
Evaluating the 2018 extreme flood hazard events in Kerala, India
(Taylor and Francis Ltd., 2020) Preet Lal; Aniket Prakash; Amit Kumar; Prashant K. Srivastava; Purabi Saikia; A.C. Pandey; Parul Srivastava; M.L. Khan
The very high anomalous precipitation (more than 500 mm) and release of water from reservoirs located in an upper catchment resulted in severe flood inundation situation in downslope regions of Kerala State in August 2018. In the present study, the satellite-based precipitation was analyzed on a daily to weekly basis during the flood duration in Kerala. The Tropical Rainfall Measuring Mission (TRMM) based precipitation pattern indicated very high rainfall (more than 60 mm day–1) in the central parts of Kerala on 14 and 15August 2018. The climate research unit (CRU) based long-term mean cumulative precipitation (1901-2017) indicated high (300-400 mm) to very high (more than 500 mm) anomalous precipitation in parts of Kerala during August 2018 leading to severe flood inundation in major parts of the state. The Sentinel-1A Synthetic Aperture Radar (SAR) based inundation mapping exhibited flooding of 1100.4 km2 area (5.80% of total area) during August 2018, which severely affected Alappuzha, Thrissur, and Kottayam districts. Cropland (218.69 km2), settlement (115.23 km2) and shrubland (79.46 km2) were the most affected land-use/land-cover in the region. The study warrants the restoration of ecological stability and augmentation of resilience to flooding hazard primarily in the upper catchments (the Western Ghats). © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.
Guest-host interaction in ferroelectric liquid crystal-nanoparticle composite system
(Indian Academy of Sciences, 2014) Pratap Dharmendra Singh; Swadesh Kumar Gupta; Satya Prakash Yadav; P.K. Sharma; A.C. Pandey; Rajiv Manohar
The present paper deals with the characterization of a ferroelectric liquid crystal-nanoparticle (FLC-NP) composite system. The dielectric, electrical and polarization property of the FLC-NP composite system have been studied as a function of temperature and frequency. Ferroelectric Cu-doped ZnO (Cu-ZnO) nanoparticles have been added to the pure ferroelectric liquid crystal (FLC) Felix 17/100. The nanoparticles are bigger in size as compared to FLC molecules; therefore, they distort the existing geometry of FLC matrix and set up an antiparallel correlation with the dipole moments of the host FLC molecules. This antiparallel correlation of guest-host geometry reduces the net ferroelectricity of the composite system and modifies all the physical properties of the pure FLC. The change in properties has been analysed and explained in the light of guest-host interaction. © Indian Academy of Sciences.
Histochemical and experimental study on the adrenal of the freshwater catfish, Ompok bimaculatus (Bloch)
(1982) A.C. Pandey; S. Haider
The adrenal tissue is situated around the cardinal vein and its branches in the pronephric head kidney. The medullary cells are largely confined to the wall of these blood vessels, whereas the cortical cells are arranged in several layers around the medullary cells. The cortical cells are eosinophilic and give positive reaction to Sudan black-B, Baker's acid haematein and Schultz's tests. In response to ACTH and thiourea treatments, the cortical cells exhibited hypertrophy, degranulation and depletion of lipid content. Pronounced cortical atrophy was evident in the hypophysectomised specimens. Marked involution was noticed in the cortical cells in response to hydrocortisone treatment. The medullary cells are larger than the cortical cells and are eosinophobic. Thgey give positive reaction to ferric-ferricyanide, PAS and ascorbic acid tests. Two types of medullary cells could be differentiated with the help of dichromate, iodate and glutaraldehyde-silver techniques. These cells did not exhibit any visible change after ACTH, hydrocortisone and thiourea treatments. However, reduction in the cellular size is obvious in the hypophysectomised fish.
Histological and histochemical study of the caudal neurosecretory system of the freshwater teleost Ompok bimaculatus (Bloch) with a note on its response to hypophysectomy and osmotic stress
(1981) S. Haider; A.C. Pandey
[No abstract available]
In situ grafted nanostructured ZnO/carboxymethyl cellulose nanocomposites for efficient delivery of curcumin to cancer
(Kluwer Academic Publishers, 2014) Laxmi Upadhyaya; Jay Singh; Vishnu Agarwal; A.C. Pandey; Shiv P. Verma; Parimal Das; R.P. Tewari
In this present manuscript, zinc oxide (ZnO) nanoparticles embedded carboxymethyl cellulose (CMC) bionanocomposite were prepared by in situ grafting and the hydrophobic anticancer drug curcumin (Cur) was loaded into it. Structural, morphological, and physiochemical behavior of prepared curcumin-loaded CMC/ZnO nanocomposites (NCs) were characterized by FTIR, XRD, SEM, TEM, TGA, and DTA. The drug entrapment efficiency was evaluated and the in vitro efficacy as anticancer drug delivery vehicle was analyzed. The potential toxicity of curcumin-loaded ZnO/CMC NCs (Cur/ZnO/CMC NCs) was studied by using L929 and MA104 cell lines via MTT assay. The cellular uptake study of Cur/ZnO/CMC NCs by normal (L929) and cancer (MA104) cells carried out by using ethanol extraction and by FACS analysis has been reported. The results of this investigation demonstrate that the nanomatrix synthesized can effectively deliver the anticancer drug curcumin, and hence appears to be a promising nanoformulation for anticancer therapy and other biomedical applications. © 2014, Springer Science+Business Media Dordrecht.
Integrating TRMM and MODIS satellite with socio-economic vulnerability for monitoring drought risk over a tropical region of India
(Elsevier Ltd, 2015) Aradhana Yaduvanshi; Prashant K. Srivastava; A.C. Pandey
Drought is a recurring feature of the climate, responsible for social and economic losses in India. In the present work, attempts were made to estimate the drought hazard and risk using spatial and temporal datasets of Tropical Rainfall Measuring Mission (TRMM) and Moderate Resolution Imaging Spectroradiometer (MODIS) in integration with socio-economic vulnerability. The TRMM rainfall was taken into account for trend analysis and Standardized Precipitation Index (SPI) estimation, with aim to investigate the changes in rainfall and deducing its pattern over the area. The SPI and average rainfall data derived from TRMM were interpolated to obtain the spatial and temporal pattern over the entire South Bihar of India, while the MODIS datasets were used to derive the Normalized Difference Vegetation Index (NDVI) deviation in the area. The Geographical Information System (GIS) is taken into account to integrate the drought vulnerability and hazard, in order to estimate the drought risk over entire South Bihar. The results indicated that approximately 36.90% area is facing high to very high drought risk over north-eastern and western part of South Bihar and need conservation measurements to combat this disaster. © 2015 Published by Elsevier Ltd.
Morphometric characteristics of glaciers in Doda Valley, Zanskar basin, J and K
(2009) Praveen Kumar Rai; K. N. Prudhvi Raju; M.S. Nathawat; A.C. Pandey
Inventory of the glaciers is of prime interest to evaluate the nature of changes in glacier dimensions and also to establish relationship between climatic change and dynamics of glaciers. As glaciological studies in high altitude terrains are very difficult by conventional methods remote sensing data is used to map and monitor of permanent snowfields and glaciers. The study area covers Doda sub-basin, with about 13 individual glaciers with one of them ranked as the second largest glacier in India, of larger Zanskar basin in Ladakh of Jammu and Kashmir. It is about 2088.46 sq km in area. Its elevation ranges from 3071-6401 m above msl. An attempt is made here to study morphometric parameters like, length, width, area, perimeter, orientation, thickness, area accumulation ratio (AAR) and specific mass balance, of the glaciers using multi-temporal satellite data (FCCs as well as digital data of bands 234 of IRS LISS III) of July to September period (when snow cover is at its minimum and permanent snow cover and glaciers are fully exposed) of 1975,1992, and 2001 in conjunction with topographical map of 1962. Altitude information is generated from Digital Elevation Model (DEM) generated with Shuttle Range Topographic Mission (SRTM) data and some inputs from SOI toposheets. The analysis reveals a decreasing trend of AAR indicating possibility of faster retreat of glaciers. The study also reveals negative mass balance compared to the recorded positive mass balance in 1975 and 1992.
Multi-phonon assisted upconversion emission and power dependence studies in LaF3:Er3+ phosphor
(2013) A.K. Singh; K. Kumar; A.C. Pandey; S.B. Rai; D. Kumar
LaF3:Er3+ phosphor is synthesized through chemical precipitation method and its upconversion (UC) emission studies have carried out using 532-nm excitation. Phosphor has shown two-photon absorption UV bands at the 325 nm, 342 nm, 383 nm, 403 nm and 411 nm wavelengths. At relatively higher excitation powers multi-phonon assisted energy migration from 2H 11/2 (4S3/2) level to the upper 4F3/2, 4F5/2 and 4F 7/2 levels has observed and this energy migration opened new channel of emission at 440 nm, 453 nm and 488 nm due to the 4F3/2 → 4I15/2, 4F5/2 → 4I15/2 and 4F7/2 → 4I15/2 transitions, respectively. Temperature dependent UC measurement is also done and observed emission pattern is correlated with the power dependence studies. Upconversion bands at 411 and 488 nm wavelengths have shown reversal in intensity as either excitation power or sample temperature is increased and hence these two bands are found to act as optical switch. Planck blackbody like continuum emission has also observed at higher excitation powers. © 2013 Elsevier B.V. All rights reserved.
Occurrence of oocytes in the liver of the percoid fish, Trichogaster fasciatus (Bloch and Schneider) and its probable significance
(1979) A.C. Pandey; S. Haider
[No abstract available]
Photon avalanche upconversion and pump power studies in LaF 3:Er3+/Yb3+ phosphor
(2011) A.K. Singh; K. Kumar; A.C. Pandey; O. Parkash; S.B. Rai; D. Kumar
Hexagonal LaF3:Er3+/Yb3+ phosphor material has been synthesized by chemical precipitation method to obtain high near-infrared to green upconversion (UC) efficiency. Its thermal, structural and fluorescence properties have been studied. UC emission bands have been observed up to 315 nm in UV region. The effect of input pump power on the intensities of various emission bands has been studied in detail and photon avalanche UC mechanism has been identified. On increasing the excitation power, some bands have shown saturation in intensity. Also, at higher pump intensities two new UC bands were observed and their origin has been discussed. The phosphor has also been tested for possible UC-based fingerprint detection. © 2011 Springer-Verlag.
Some histochemical and experimental studies on the adrenal gland of a percoid fish, Trichogaster fasciatus (Bloch & Schneider)
(1980) S. Haider; A.C. Pandey
[No abstract available]