Browsing by Author "Vijay Kumar Mishra"

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Comparative efficacy of newer molecules against leafhopper and mites on okra Abelmoschus esculentus
(Malhotra Publishing House, 2017) Ramesh Kumar Rawat; M. Raghuraman; Vijay Kumar Mishra
Results revealed that maximum jassid mortility was observed in propargite 50% + bifenthrin 5% SE @ 621 + 62.1 g a.i/ha (1.10/leaf), while minimum was observed in lambda cyhalothrin 4.9 CS 15 g ai/ha (3.52/ leaf) up to seven days of application. Which also suppressed the mite population. Application of Propargite 50% + Bifenthrin 5% SE @ 621 + 62.1 g a.i/ha (14.97 ton/ha) also gave maximum green fruit yield. © MPH.
Effect of a chelating agent at different pH on the spectroscopic and structural properties of microwave derived hydroxyapatite nanoparticles: A bone mimetic material
(Royal Society of Chemistry, 2016) Vijay Kumar Mishra; Birendra Nath Bhattacharjee; Devendra Kumar; Shyam Bahadur Rai; Om Parkash
In the present investigation, the effect of a capping agent (EDTA) and pH on the optical and structural characteristics of HAp nanoparticles (NPs) has been studied. Six samples of HAp were synthesized under six different chemical conditions. The HAp specimens were prepared via a microwave irradiation technique (MWIT) in the presence and absence of EDTA at three different pH values 9, 11 and 13. All the samples were calcined at 900 °C. HAp NPs with different sizes and shapes were found to be developed. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques were employed to determine the crystal structure, crystallite size and bonding parameters of the resulting HAp. The SEM measurements revealed the formation of the different morphologies of the HAp NPs under different physico-chemical conditions. Electron microscopies revealed that the particle size of the samples was in the range of ∼10-200 nm. The TEM results were in good agreement with the SEM results. The study revealed the vital role of the chelating agent (EDTA) in the formation of the pure phase HAp nanostructures. EDTA assisted the formation of needle-like nanorods of HAP and prevented agglomeration. EDTA also prevented carbonate impurities. Carbonate impurities, probably from the atmosphere, were observed in the HAp samples formed without EDTA. Despite the effect of EDTA, the pH of the solution also played a key role in deciding the final morphology of the HAp nanostructures. The samples were also characterized spectroscopically using Fourier transform infrared (FT-IR) spectroscopy and Raman techniques to understand the molecular interactions. The application of laser induced breakdown spectroscopy (LIBS) detected the presence of N and further confirmed the formation of the HAp powders. © 2016 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Enhanced mechanical properties of hBN-ZrO2 composites and their biological activities on: Drosophila melanogaster: Synthesis and characterization
(Royal Society of Chemistry, 2019) Amarendra Gautam; Chandkiram Gautam; Monalisa Mishra; Vijay Kumar Mishra; Ajaz Hussain; Swetapadma Sahu; Reetuparna Nanda; Bikash Kisan; Santoshkumar Biradar; Rakesh Kumar Gautam
In this study, six compositions in the system [x(h-BN)-(100 - x)ZrO2] (10 ≤ x ≤ 90) were synthesized by a bottom up approach, i.e., the solid-state reaction technique. XRD results showed the formation of a novel and main phase of zirconium oxynitrate ZrO(NO3)2 and SEM exhibited mixed morphology of layered and stacked h-BN nanosheets with ZrO2 grains. The composite sample 10 wt% h-BN + 90 wt% ZrO2 (10B90Z) showed outstanding mechanical properties for different parameters, i.e., density (3.12 g cm-3), Young's modulus (10.10 GPa), toughness (2.56 MJ m-3), and maximum mechanical strength (227.33 MPa). The current study further checked the in vivo toxicity of composite 10B90Z and composite 90B10Z using Drosophila melanogaster. The composite 10B90Z showed less cytotoxicity in this model, while the composite 90B10Z showed higher toxicity in terms of organ development as well as internal damage of the gut mostly at the lower concentrations of 1, 10, and 25 μg mL-1. Altogether, the current study proposes the composite 10B90Z as an ideal compound for applications in biomedical research. This composite 10B90Z displays remarkable mechanical and biological performances, due to which we recommend this composition for various biomedical applications. © ??? The Royal Society of Chemistry.
Erratum: Effect of a chelating agent at different pH on the spectroscopic and structural properties of microwave derived hydroxyapatite nanoparticles: a bone mimetic material (New J. Chem. (2016) 40 (5432–5441) DOI: 10.1039/C5NJ03322E)
(Royal Society of Chemistry, 2022) Vijay Kumar Mishra; Birendra Nath Bhattacharjee; Devendra Kumar; Shyam Bahadur Rai; Om Parkash
The authors regret their oversight in omitting to attribute Fig. 6 in this paper to its original source, a previous publication by the authors in Ceramics International, cited as ref. 30 in the original article. Prior to publication, the authors had sought permission to reproduce the images in Fig. 6. They regret not including an appropriate attribution statement in the figure caption. There is also an error in the reported pH values in the original article. Any values stated at pH 13 in the paper should be changed to pH 14. The corrected caption for Fig. 6 is shown below: Fig. 6 SEM images of the HAp precursor powder at pH 9 (a), HAp powder at pH 14 and using EDTA (b), and the HAp powders obtained upon calcination at (c) 600 1C and (d) 900 1C using precursor powder (a). Reproduced from Vijay K. Mishra et al., Ceramics International, 2014, 40, 11319–11328, with permission from Elsevier. The sentence in Section 3.2.2 ‘‘Sample (a) and (b) were...’’ on page 5437 should be changed to ‘‘Sample (a) was the HAp precursor powder prepared using EDTA at pH 9. Sample (b) was the HAp powder at pH 14 and using EDTA.’’ In addition, the authors regret unattributed text overlap with ref. 30 in Section 3.2.3. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers. © 2022 The Royal Society of Chemistry.
Evaluate the bio-efficacy of Imidacloprid 17.8 SL against aphid Aphis gossypii glover on Okra Abelmoschus esculentus (L.) Moench
(EM International, 2016) Raj Veer; Vijay Kumar Mishra; Gopi Ram Yadav; Deepika Chuahan; R.S. Bisht
During kharif cropping season, During kharif cropping season, the treatment of Imidacloprid 17.8% SL @ 40 g a.i./ha has been found most effective insecticide against the population of Aphis gossypii on okra followed by Imidacloprid 17.8% SL @ 30 g a.i./ha. Maximum fruit yield (14.97 T/ha) was also recorded with Imidacloprid 17.8% SL @ 40 g a.i./ha treated plots. However, Imidacloprid 17.8% SL @ 10 and 20 g a.i./ha and Quinalphos 25% EC (FLASH) @ 250 g a.i./ha, where the aphid population was significantly less than untreated control appeared to be the safest treatment to non target organism. Copyright@ EM International.
Fabrication of Graphene Nanoplatelet-Incorporated Porous Hydroxyapatite Composites: Improved Mechanical and in Vivo Imaging Performances for Emerging Biomedical Applications
(American Chemical Society, 2019) Sunil Kumar; Chandkiram Gautam; Vijay Kumar Mishra; Brijesh Singh Chauhan; Saripella Srikrishna; Ram Sagar Yadav; Ritu Trivedi; Shyam Bahadur Rai
Three-dimensional nanocomposites exhibit unexpected mechanical and biological properties that are produced from two-dimensional graphene nanoplatelets and oxide materials. In the present study, various composites of microwave-synthesized nanohydroxyapatite (nHAp) and graphene nanoparticles (GNPs), (100 - x)HAp-xGNPs (x = 0, 0.1, 0.2, 0.3, and 0.5 wt %), were successfully synthesized using a scalable bottom-up approach, that is, a solid-state reaction method. The structural, morphological and mechanical properties were studied using various characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and universal testing machine (UTM). XRD studies revealed that the prepared composites have high-order crystallinity. Addition of GNPs into nHAp significantly improved the mechanical properties. Three-dimensional nanocomposite 99.5HAp-0.5GNPs exhibited exceptionally high mechanical properties, for example, a fracture toughness of ∼116 MJ/m3, Young's modulus of ∼98 GPa, and compressive strength of 96.04 MPa, which were noticed to be much greater than in the pure nHAp. The MTT assay and cell imaging behaviors were carried out on the gut tissues of Drosophila third instars larvae and on primary rat osteoblast cells for the sample 99.5HAp-0.5GNPs that have achieved the highest mechanical properties. The treatment with lower concentrations of 10 μg/mL on the gut tissues of Drosophila and 1 and 5 μg/mL of this composite sample showed favorable cell viability. Therefore, owing to the excellent porous nature, interconnected surface morphology, and mechanical and biological properties, the prepared composite sample 99.5HAp-0.5GNPs stood as a promising biomaterial for bone implant applications. © 2019 American Chemical Society.
Formation of multifunctional ZrO2–MgO-hBN nanocomposite for enhanced bone regeneration and E coli bacteria filtration applications
(Elsevier Ltd, 2020) Ajaz Hussain; Chandkiram Gautam; Asif Jafri; Vijay Kumar Mishra; Abhishek Madheshiya; Amarendra Gautam; Manvandra Kumar Singh; Rakesh Kumar Gautam; Manisha Gupta; Md Arshad; Robert Vajtai; Pulickel M. Ajayan
Due to adequate properties, bone implant materials have attracted much attention to repair the large-sized bone fractures which cannot be auto-healed. Recently, three-dimensional (3-D) nanocomposites were synthesized using two-dimensional (2-D) materials which reveals unexpected performances. In the present study, 3-D mesoporous biocomposites were developed for bone/dental implant applications. A ternary novel biocomposite system ZrO2–MgO-hBN was fabricated with low density, high strength, and mesoporous interconnected architecture using conventional bottom-up synthesis method. Due to remarkable stability in different fluids such as water, minimum essential medium eagle-alpha modification (α-MEM), acids and oils, the fabricated biocomposites displayed multifunctional activities along with suitable proliferation of osteoblast like MG63 cell and filtration of Escherichia coli (E-coli) bacteria from the water. Moreover, the biocomposite exhibited protective nature from harmful ultraviolet (UV) radiation. A new phase of hexagonal boron nitride (h-BN) in the form of highly porous nanotubes was observed that opens the new possibility to optimize the synthesis of porous h-BN nanotubes to explore their further applications. Therefore, based on mechanical, tribological and biological performances, the nanocomposite is a biomimetic material having potential as bone/dental implant and can be used for multifunctional applications. © 2020 Elsevier Ltd and Techna Group S.r.l.
Impact of various insecticides on natural enemies in cowpea ecosystem
(Malhotra Publishing House, 2017) Gopi Ram Yadav; Poonam Srivastava; Vijay Kumar Mishra; Deepika Chauhan; Rajveer
Studies on the impact of various insecticides on natural enemies in cowpea crop revealed that all the insecticides caused harmful effect on the population of coccinellid beetles and spiders. Bio-rationals, Bacillus thuringiensis var. Kurstaki and azadirachtin were found comparatively safe. The population of coccinellid beetles gradually decreased in all treatments whereas untreated check recorded significantly more number of beetles/plant/plot while the population of spiders gradually increased in all treatments.
Mg-doped hydroxyapatite nanoplates for biomedical applications: A surfactant assisted microwave synthesis and spectroscopic investigations
(Elsevier Ltd, 2014) Vijay Kumar Mishra; Birendra Nath Bhattacharjee; Om Parkash; Devendra Kumar; Shyam Bahadur Rai
Nanoplates of Mg doped hydroxyapatite (Mg-HAp) were derived successfully and rapidly via microwave irradiation technique. Hydroxyapatite (HAp) is the hard tissues and main inorganic component in mammals. Different nanostructures of HAp exist in different parts of human bone but nanorods are very common due to its intrinsic nature to grow in rode-like structure under physiological as well as under applied ambient conditions in laboratory. On the addition of Mg at very low level (0.06 mol%) in pure HAp results the formation of 2-D plate-like nanostructures rather than rod-like which is the matter of interest. In this attempt our efforts have been focused on the study of effect of Mg incorporation on structural and spectroscopic properties of HAp prepared via microwave irradiation technique. This technique is preferred due to several advantages viz. very fast as well as homogeneous heating, time/energy saving and eco-friendliness. The calcium nitrate tetrahydrate (Ca(NO3) 2̇4H2O)) as a source of calcium, magnesium nitrate hexahydrate (Mg(NO3)2̇6H2O) as a source of magnesium, disodium hydrogen phosphate dihydrate (NaH2PO 4̇2H2O) as a source of phosphorous and sodium ethylene diamine tetra acetate (NaEDTA) as a surfactant were used as starting reagents. Sodium hydroxide (NaOH) pellets were employed to adjust the pH value of final solution. The solution of fixed pH value was kept into the microwave oven generating waves of frequency 2.45 GHz (water absorption frequency) and power 750 W for 8 min. The precipitate thus obtained was washed, centrifuged and then dried at 100 °C for 2 h. Dried powder was then calcined at 700°C for 2 h. The bright white powder thus obtained was characterized structurally using X-ray diffraction and SEM techniques and spectroscopically by FT-IR and Raman techniques. Structural and spectroscopic analysis revealed the formation of Mg doped HAp [Mg-HAp: (Ca4.94Mg0.06) (PO4) 3OH], nanoplates having average crystallite size of 26 nm as estimated by Scherrer's formula. © 2014 Elsevier B.V. All rights reserved.
Position Statement of ISCCM on Intrahospital Transport of Critically Ill Patients
(Jaypee Brothers Medical Publishers (P) Ltd, 2025) Kapil Gangadhar Zirpe; Anand Mohanlal Tiwari; Atul Prabhakar Kulkarni; Deepak Govil; Srinivas Samavedam; Jeetendra Sharma; Subhal Bhalchandra Dixit; Manish Munjal; Sharmili Sinha; Yogendra Pal Singh; Sumalatha Arunachala; Swarna D. Kaurgayala; Shweta Ram Chandankhede; Syed Moied Ahmed; Susruta Bandyopadhyay; Sunil Karanth; Vijay Kumar Mishra; Anand Paikuji Dongre; Bikram Kumar Gupta; Pragyan Kumar Routray; Rajesh Singh Nongthombam; Bharat G. Jagiasi; Pradip Kumar Bhattacharya; Subhash Kumar Todi
Background and purpose: Intrahospital transport (IHT) of critically ill patients is essential for diagnostic and therapeutic indications, requiring thorough assessment and careful preparation of patients, staff, and equipment throughout the process. Variability in practices among hospitals can affect patient safety and may result in adverse events (AEs). This position statement is designed to provide guidance to multidisciplinary critical care teams in the adoption of evidence-based recommendations aimed at mitigating risks and improving safety during patient transport. Method: This position statement has been drafted by an expert committee on IHT constituted by the Indian Society of Critical Care Medicine. The process involved thorough review of literature from electronic database using PubMed services. Recommendations made are tailored with considerations for Indian setting; the units may further modify these as per local needs and equipment and staffing available. The final manuscript was written after achieving consensus among members, and final draft was accepted by all the committee members. Results: This position statement offers a compilation of 38 strategic recommendations, which are comprehensive and deal with all aspects of IHT of the critically ill. Recommendations provided in this document are, therefore, applicable for routine use during the IHT. They cover all phases of transport and answer questions pertaining to pre-, intra-, and post-transport considerations. It will help to achieve uniformity, minimize AEs, and enhance safety. Conclusions: This is a standard set of 38 evidence-based recommendations to ensure safety for IHT, tailored for implementation in various criticalcare settings across India. Science is ever-changing, and periodic review will be needed to keep it up to date with emerging evidence and standards. © The Author(s). 2025.
Relationship between incidence of Leucinodes orbonalis Guenee and sugar content present in the shoots and fruits of different brinjal varieties
(Malhotra Publishing House, 2017) Kantipudi Rajesh Kumar; D. Rakshith Roshan; Sudhir Kumar; Vijay Kumar Mishra
In a two year study, amongst the varieties tested results revealed that maximum sugar content was recorded in the shoots of susceptible variety CO-2, while, minimum sugar content was in the resistant variety Arka Keshav. In fruits also highest sugar content was recorded in CO-2 while Arka Keshav recorded lowest sugar content in fruits 2nd year. The shoots and fruits infestation with sugar content present showed significantly positive correlation indicating that increase in sugar content in shoots and fruits will increase shoot and fruit infestation of L. orbonalis. © MPH.
Reliable screening technique for resistance/susceptible traits against mustard aphid, Lipaphis erysimi (Kalt.) under field conditions
(Malhotra Publishing House, 2019) Vijay Kumar Mishra; N.N. Singh; Sambhrant Kumar
Twenty two varieties/lines of Indian mustard (Brassica juncea L.) were evaluated against mustard aphid, Lipaphis erysimi (Kalt.) NDR08-14-1 and NDR08-1 showed least aphid infestation index (0.7) and came under resistant category. NDYR-8, MCN14-33, MCN14-31, MCN14-24 and NDR1-11 with aphid infestation index (1.4) proved moderately resistant while, MCN14-23, MCN14-27, and NDR07-2 with aphid infestation index (1.75) were moderately susceptible. Six lines NDR8501, MCN14-32, NDR-7, MCN14-25, MCN14-29 and VARUNA were found susceptible (2.8 index). NDRS 2010, DIVYA-33, MCN 14-30,NDRS 9-2 and NDRS 2001-1 were found highly susceptible (4.26 index). The maximum yield was obtained from NDR08-14-1 (13.14 q/ha) and minimum yield from NDRS2001-1 (6.71 q/ha). © 2019 Malhotra Publishing House.
Seasonal incidence of rice yellow stem borer, Scirpophaga incertulas (Walker) on different accessions in rice agro-ecosystem
(Malhotra Publishing House, 2017) Ashutosh Kumar Arya; Vijay Kumar Mishra; Sunil Verma; C.P. Singh
Studies on population dynamics of yellow stem borer on different rice varieties revealed that the dead heart formation was observed from the 2nd week of August and peak deadheart formation was observed during 4th week of September in PS-15 (30.3%) followed by PR-113 (26.7%) and was minimum in HKR-4 (14.6%). The white ear head formation started from the 1st week of September and attained its peak during 2nd week of November with maximum white ears in NDR-359 (44.9%) followed by PR-113 (44.3%) and minimum in variety PS-5 (27%). White earhead symptom and weather parameters, showed that varieties, PR-113, HKR-47 and PS-15 exhibited significant negative correlation with maximum temperature. Significant negative correlation values -0.962, -0.927, -0.903, -0.931, -0.940 and -0.931 were recorded in varieties, PR-113, HKR-47, PS-4, NDR- 359, Sarju-52 and PS-21, respectively with minimum temperature. Varieties PR-113, NDR-359, and Sarju-52 showed significant negative correlation with minimum relative humidity.
Structural and crystallization behavior of (Ba,Sr)TiO3 borosilicate glasses
(2013) Avadhesh Kumar Yadav; C.R. Gautam; Arvind Gautam; Vijay Kumar Mishra
Various glass samples were prepared by melt quench technique in the glass system [(Ba1-x Srx) TiO3]-[2SiO 2-B2O3]-[K2O] doped with 1 mole% of La2O3. Infrared spectra show the number of absorption peaks with different spliting in the wave number range from 450 to 4000 cm -1. Absorption peaks occurs due to asymetric vibrational streching of borate by relaxation of the bond B-O of trigonal BO3. Raman spectra show the Raman bands due to ring-type metaborate anions, symmetric breathing vibrations BO3 triangles replaced by BO4 tetrahedra, and symmetric breathing vibrations of six-member rings. The differential thermal analysis of a glass sample corresponding to composition x = 0.0 shows crystallization temperature at 847°C and glass transition temperature at 688°C. X-ray diffraction (XRD) pattern of glass ceramic samples shows the major crystalline phase of BaTiO3 whereas pyrochlore phases of barium titanium silicate. Scanning electron micrographs confirm the results of XRD as barium titanate is major crystalline phase along with pyrochlore phase of barium titanium silicate. © 2013 Copyright Taylor and Francis Group, LLC.
Structural investigations on nickel substituted zinc magnesium ferrites nanoparticles formed via co-precipitation method
(Elsevier B.V., 2024) Farhana Naaz; Preeti Lahiri; Vijay Kumar Mishra; Hemant Kumar Dubey; Pankaj Kumar Tripathi; Ehsan Shakerzadeh
The present study provides a comprehensive structural investigation on Mg0.5Zn0.5−xNixFe2O4 nano-ferrites. Nano-crystalline Mg0.5Zn0.5−xNixFe2O4 (x = 0.0,0.1,0.2,0.3,0.4) powder samples were synthesized using co-precipitation process followed by calcinations at 600 °C for 6 h. The purity and phase of thus prepared samples were confirmed using X-ray Diffraction, Atomic Force Microscopy and X-ray Photoelectron Spectroscopy techniques. The average crystallite size, determined using the Debye-Scherrer method, was estimated to be between 17 and 26 nm. The average particle size ranged from 26.9 nm to 13.1 nm. It was evident that as the nickel concentration increases in Mg-Zn-Ni ferrite, the average grain size decreases from 26.1 nm to 10.9 nm, indicating denser samples with higher nickel concentrations. The ferrites were found to be porous and at the nanoscale, with sizes less than 30 nm. Raman studies supported the presence of iron-oxide phases, confirming the spinel structure with tetrahedrally and octahedrally occupied iron sites. The low coercivity (Hc) values observed in the hysteresis loops indicate soft magnetic characteristics for all samples. This is advantageous for applications in recording heads, inductor and transformer cores, magnetic shielding, the high-frequency range, particularly in deflection yoke rings, microwave devices, and drug delivery. © 2024 Elsevier B.V.
Structure of Apatite Nanoparticles Derived from Marine Animal (Crab) Shells: An Environment-Friendly and Cost-Effective Novel Approach to Recycle Seafood Waste
(American Chemical Society, 2019) Birendra Nath Bhattacharjee; Vijay Kumar Mishra; Shyam Bahadur Rai; Om Parkash; Devendra Kumar
In the present investigation, crab shells as seafood wastes were successfully recycled into an extremely useful biomaterial by the thermal treatment method. Thermogravimetric-differential thermal analysis studies concluded that the calcination temperature must be beyond 570 °C to get a fine and crystalline apatite powder from the crab shells. Thus, the calcination temperature is taken to be 700 °C. Powder X-ray diffraction analysis of the calcined crab shells revealed hydroxyapatite (HAp)/carbonated HAp (CHAp) with an average crystallite size of 24.4 nm. Scanning electron microscopy revealed the surface morphology of the crab shells-derived apatite powder as needle-like nanorods of HAp of diameter ≈ 100-300 nm and nanospheres of CHAp of diameter ≈ 100-500. Energy-dispersive X-ray spectroscopy showed the presence of calcium, phosphorous, magnesium, and oxygen as major elements in the apatite constituents. Fourier transform infrared as well as Raman spectroscopies confirmed the formation of apatite powder. X-ray photoelectron spectroscopy results indicated the electronic environment and oxidation states of the constituent elements, Ca, C, and P. On the basis of the results obtained from various characterization techniques, the overall study emphasized an environment-friendly and cost-effective approach for recycling of the bio-pollutant and synthesis of ultra-fine, ultra-crystalline apatite-based excellent biomaterial derived from crab shells as seafood wastes with its application as a futuristic biomaterial in bone/teeth implants. © 2019 American Chemical Society.
Studies on the influence of biotic and abiotic factors on aphid, Lipaphis erysimi Kalt. Population under mustard ecosystem
(Malhotra Publishing House, 2017) Sambhrant Kumar; N.N. Singh; Vijay Kumar Mishra
Attempts were made to study the influence of biotic and abiotic factors on aphid, L. Erysimi Kalt. Population under mustard crop ecosystem during rabi season of 2015-2016. The correlation studies of aphid population with bioagent population showed negative impact with 'r' value of -0.5446 with a regression coefficient 0.1550 and is observed to be statistically non-significant even at p ≤ 0.05. The regression equation fitted with the bioagent revealed that for every increase of one unit of bioagent there would be a decrease of 0.1550 number of test insect. The occurrence of bioagent population was observed during third week of January when the mean aphid population was varying between 10.07 to 21.67 aphid/ 10 cm terminal shoot. During 3rd week of January the mean of bioagent population was observed to be 0.04 per plant on 20.01.2016. However the effect of abiotic factors (temperature, humidity, rainfall) with aphid population revealed that maximum and minimum temperature were found to be statistically non-significant with a regression coefficient of -0.1807 and 0.3191, maximum and minimum relative humidity were also statistically non-significant with a regression coefficient of 0.0521 and -0.0761 and rainfall have negative correlation with aphid population r = -0.7650 with a regression coefficient of -0.0098. The maximum and minimum temperatures on day of observation were 19°C and 11°C and the maximum and minimum relative humidity were 94 per cent and 69 per cent, respectively. On successive days of observation at an interval of 7 days the bioagent population gradually increased till 24.02.2016 reaching to a peak of mean population of 1.52 per plant.
Study of morphological behavior of hydroxyapatite, EDTA hydroxyapatite and metal doped EDTA hydroxyapatite synthesized by chemical co-precipitation method via hydrothermal route
(Trans Tech Publications Ltd, 2017) Birendra Nath Bhattacharjee; Vijay Kumar Mishra; Shyam Bahadur Rai; Om Parkash; Devendra Kumar
Hydroxyapatite Ca10(PO4)6(OH)2: (HAp) with stoichiometric composition and Ca/P (ratio) = 1.67 has attracted much attention in the context of bone transplant due to its similarity with the mineral constituent of mammals bone and teeth. It is frequently used as a filler to replace amputated bone or as a coating to promote bone in growth into prosthetic implants. Biomimetics or biomimicry is the imitation of the models, systems, and elements of nature for the purpose of solving complex human problems. Living organisms have evolved well-adapted structures and materials over geological time through natural selection. Biomimetics has given rise to new technologies inspired by biological solutions at macro and nanoscales. Nanostructure modification of dental implants has long been sought as a means to improve osseointegration through enhanced biomimicry of host structures. Several methods have been proposed and demonstrated for creating nanotopographic features. In the present investigation hydroxyapatite and metals (scandium, magnesium and neodymium) doped hydroxyapatite were successfully synthesized in laboratory by chemical precipitation using hydrothermal route and also by taking ethylene diamine tetra-acetic acid as a complexing reagent. The crystal, grain, and bonding structures of resulting HAp were characterized structurally using X-ray diffraction(XRD) and scanning electron microscopy (SEM) techniques and spectroscopically using Fourier transform infrared (FT-IR) techniques. From SEM analysis it was found that the irregular structure of HAp changes to nano rods with EDTA HAp which further gets converted to dandelium structure with scandium doping, plate structure with magnesium doping and whiskers structure on doping with neodymium. © 2017 Trans Tech Publications.
Synthesis and catalytic activity of Cu-Cr-O-TiO2 composites for the thermal decomposition of ammonium per-chlorate: enhanced decomposition rate of fuel for solid rocket motors
(Royal Society of Chemistry, 2017) Harish Kumar; Prahalad N. Tengli; Vijay Kumar Mishra; Pankaj Tripathi; Dan Bahadur Pal; Pradeep Kumar Mishra
This study presents the sol-gel synthesis of Cu-Cr-O·nTiO2 particles calcined at different temperatures and their catalytic effects on thermal decompostion of AP. The study focuses on the impact of crystallite size, shape and concentration of TiO2 in the catalyst composition on the thermal decomposition behaviour of ammonium per-chlorate (AP). During synthesis, the molar ratio of Cu/Cr was kept to 0.7 and TiO2 nanoparticles were added into Cu-Cr-O-citric acid solution at different molar ratios to form three different compositions of the catalyst Cu-Cr-O·nTiO2 (n = 0.5, 0.7 and 0.9 mol%). The effect of temperature on the thermal, structural and spectroscopic properties of the different Cu-Cr-O compositions was also studied by calcining them at two different temperatures, 300 and 1050 °C. Post synthesis characterizations of the prepared catalysts were carried out by using XRD, FT-IR, SEM, EDAX and TEM (with SAED pattern) techniques. The desired qualification of Cu-Cr-O-citric acid (the precursor of the catalyst) and the final compositions of the catalysts were carried out by using thermogravimetric and differential thermal analysis (TG-DTA) techniques. The efficiency of the synthesized catalysts was evaluated on thermal decomposition behaviour of AP using TG-DTA techniques. The Cu-Cr-O·nTiO2 composition with the molar ratio of n = 0.7 was found to be the most efficient catalyst for decomposition of AP; it was much better than other laboratory prepared samples (n = 0.5 and 0.9) as well as the industrial catalyst (i.e. activated copper chromite (ACR); Cu-Cr-O). Further experimental work showed that addition of 10 wt% Cu-Cr-O·0.7TiO2 into AP significantly lowered the AP decomposition temperature to 306 °C from 385 °C and was accompanied by a very sharp exothermic peak indicating a single stage decomposition. The excellent finding of the study was also verified by heat of reaction (i.e. calibrated delta H) values. This study finds potential application due to the remarkable enhancement in the thermal decomposition rate of the AP used as oxidizer in propellant of solid rocket motors (SRMs) and space vehicles (SVs) at lower decomposition temperature. The fast decomposition rate of oxidizer at lower decomposition temperature enhances the efficiency of fuel which ultimately will enhance the efficiency of SRMs and SVs. © The Royal Society of Chemistry.
Synthesis and enhanced mechanical properties of MgO substituted hydroxyapatite: A bone substitute material
(Royal Society of Chemistry, 2016) C.R. Gautam; Sunil Kumar; Santoshkumar Biradar; Sujin Jose; Vijay Kumar Mishra
Hydroxyapatite (HAp) nano-ceramic powder was synthesized successfully via microwave irradiation technique. To study the effect of MgO inclusion on the mechanical properties of pure HAp, its composites with different (0.1, 0.2, 0.3 and 0.5) wt% of MgO were prepared. The influence of sintering temperature on the mechanical properties of pure HAp and its composites with MgO was also observed at 1000, 1100, 1200 and 1300 °C respectively. Samples were characterized by using X-ray diffraction (XRD) to determine the phase stability. The mechanical properties of pure HAp and its composites with MgO were measured using several parameters such as density, Young's modulus, fracture toughness, load bearing capability and porosity. It was revealed that MgO addition significantly enhanced the grain growth as well as the mechanical properties of HAp. The HAp composite modified with 0.5 wt% of MgO sintered at 1200 °C exhibited the best mechanical characteristics. This composite exhibits density of 3.04 g cm-3, Young's modulus of 126.31 GPa, fracture toughness of 178.58 MJ cm-3 and a maximum load bearing capability of 11.61 kN. To authenticate the biocompatibility of prepared biomaterials, the cell viability (MTT assay) was carried out and the mechanically best composite was found to be compatible for biomedical applications. © The Royal Society of Chemistry 2016.