654 research outputs found
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Impact on optical, electrical and antibacterial response of microwave irradiated silver nanoparticles
No full textSilve spectroscopy, Fourier transform infrared spectroscopy (FTIR), photoluminescence, Raman spectroscopy, X-ray powder diffraction (XRD), scanning and transmission electron microscopy (SEM–TEM), zeta potential and dynamic light scattering (DLS). The presence of surface plasmon resonance (SPR) band (416 nm) confirmed fabrication of AgNPs. The effect of microwave irradiation time showed that the size, shape and stability of AgNPs depend on increasing of peak intensity with increasing reaction time. FTIR spectrum confirmed the possible functional group in the product indicating presence of PVP. The enlargement in the size and agglomeration of nanoparticles were prevented by r nanoparticles (AgNPs) have been formulated using microwave irradiation from non-aqueous solution of silver nitrate (AgNO3) and poly (N-vinyl-2-pyrrolidone) (PVP) as a stabilizer. Ethanol has also been reacted like a reducer for microwave irradiation process which is quite rapid, homogeneous and efficient. The as synthesized AgNPs was further characterized by ultraviolet–Visible (UV–Vis)encapsulation of PVP during the reaction. XRD spectra illustrated that AgNPs are higher crystalline having face-centered cubic surface. The morphological analysis found that the AgNPs are homogeneous and spherical with the size of 18 ± 5 nm. The zeta potential measurement affirms the higher stability of AgNPs due to its negatively charged surface. The prepared AgNPs also exhibited electrical properties obeying the ohm’s law and significantly antimicrobial activities against Escherichia coli due to the small size
Glycoconjugates coated gold nanorods based novel biosensor for optical detection and photothermal ablation of food borne bacteria
No full textFoodborne bacterial species have been identified as the major cause in most of the severe pathogen related diseases. Conventional methods like plating and enzyme-linked immunosorbent assay (ELISA) are time overriding and laborious. Fast detection of bacterial species in food is a proximate obligation to guarantee food safety. Nanotechnology has emerged as a great field in case of rapid detection of pathogens in recent years. In the present work, gold nanorods, (AuNRs) based sensor was developed for swift and sensitive detection of foodborne bacteria. AuNRs has good electro-optical properties due to its Near-Infrared (NIR) absorption and scattering in surface plasmon resonance (SPR) wavelength regions. By exploiting the sugar based adhesion properties of bacteria, the sugar capped AuNRs can be used as potential nanobiosensor to detect the food borne bacteria. Polyethylene glycol (PEG) coated AuNRs were covalently functionalized with different types of amine terminated sugar using EDC coupling reaction. The sensitivity of synthesized nanobiosensor was probed by lectin binding assay and also with food borne bacteria (Escherichia coli) by using spectrophotometric and microscopic techniques. Pseudomonas aeruginosa was also used to probe the specificity of our synthesized biosensor through lectin-sugar interaction. Due to the specific interaction of sugar coated probe with foodborne bacteria, our nanoprobe has shown significant and selective photoablation of targeted bacteria. This nanorod based nanobiosensor can be an ideal candidate for optical detection and ablation of foodborne bacteria
Climate change drives glacier retreat in Bhaga basin located in Himachal Pradesh, India
No full textThis paper reports changes in different glaciers of Bhaga basin located in western Himalaya, from 1979 to 2017. Glacier boundaries were delineated through semi-automated approach using Landsat satellite imagery. The variation of glacier extent in different elevation zones, snout retreat and decadal changes are observed. Results show that the total area of glaciers was 238 km2 in 1979, which reduced to 230.8 km2 by 2017 (retreat rate 12 m yr−1). Glaciers at low elevation and smaller in size are retreating faster. Analysis of Asian Precipitation-Highly Resolved Observational Data Integration Towards Evaluation data shows decreasing trend of annual precipitation (–2.724 mm yr−1, 1951–2015 and increasing trend of mean annual temperature (0.021° C yr−1). The statistical analysis using Mann-Kendall and Sen’s slope tests, applied at different confidence interval demonstrates that climate change corresponds to deglaciation, and topography controls glacier recession in the basin
Label-free detection of Escherichia coli bacteria by cascaded chirped long period gratings immunosensor
No full textAn optical fiber based immunosensing platform formed by two identical chirped long period gratings (CLPGs) for sensitive and label-free detection of Escherichia coli (E. coli) is presented. The proposed immunosensor having two CLPGs with an inter-grating space (IGS) works like a Mach-Zehnder interferometer. The important feature of this sensor is that by changing the refractive index (RI) induced phase at the IGS region, a corresponding shift in resonance wavelength can be realized without affecting the actual grating region. Additionally, the confining bandwidth of the interference fringes promotes greater resolution in the resonance wavelength analysis of the transmission spectrum. The main aim of this study was the specific and rapid detection of the E. coli bacteria in phosphate buffer saline (detection range: 10 cfu/ml to 60 cfu/ml) by using the bio-functionalized IGS region as a sensing probe of the dual CLPG structure. The observed detection limit was 7 cfu/ml. For specificity analysis, Salmonella typhimurium and Staphylococcus aureus were tested and no significant shift in resonance wavelength was observed. In addition, the proposed immunosensor has the ability to selectively detect E. coli in real samples including lake water. The high specificity, good sensitivity to ambient RI, and robustness of the developed sensing platform will open a new avenue in optical immunosensing technology, and cascaded long CLPG sensors can contribute significantly to the detection of pathogenic bacteria in water and food samples
Development of biosurfactant-based graphene quantum dot conjugate as a novel and fluorescent theranostic tool for cancer
No full textBiosurfactants are amphipathic molecules of microbial origin that reduce surface and interfacial tension at gas–liquid–solid interfaces. Earlier, the biosurfactant was isolated and characterized in our laboratory from Candida parapsilosis. The property of the biosurfactant is further explored in this study by using quantum dots (QDs) as nanocarrier
RADAR absorption study of BaFe12O19/ZnFe2O4/CNTs nanocomposite
No full textMagnetic composite comprising barium hexaferrite and zinc spinel ferrite nanoparticles, BaFe12O19/ZnFe2O4 has been synthesized by auto-combustion method including citrate precursor using the sol-to-gel (S–G) followed by gel-to-nanocrystalline (G–N) conversion. The resulting ‘as synthesized’ powder is heat treated (HT) at 700 °C for 2 h in air atmosphere. The hysteresis loops show an increase in saturation magnetization from 24.10 to 53.49 emu/g with increasing HT temperatures. The multiwalled carbon nano tubes (CNTs) were synthesized by thermal decomposition of acetylene gas over iron-catalyst coated silicon substrate in the temperature range of 750–800 °C. A RADAR absorbing medium is developed by dispersing CNTs in the magnetic composite of barium and zinc ferrite nanoparticles. Reinforcement of certain mass of CNTs improves the RADAR absorption properties and wave band of BaFe12O19/ZnFe2O4 absorbent. When 20 wt% CNTs is mixed with BaFe12O19/ZnFe2O4 nanoparticles to fabricate a composite with 2 mm thickness, the maximum reflection loss reaches to −43.22 dB at 10.30 GHz and −10 dB bandwidth reaches 2.95 GHz
Synthesis and characterization of RADAR absorbing BaFe12O19/NiFe2O4 magnetic nanocomposite
No full textMagnetic composite comprising nickel ferrite and barium hexaferrite; BaFe12O19/NiFe2O4 nanoparticles having super paramagnetic nature were synthesized by co-precipitation method. The resulting precursors were heat treated (HT) at 800, 1000 and 1200°C for 4 h in nitrogen atmosphere. The ‘as synthesized’ particles have size in the range of 20–22 nm with spherical shape. Further, this spherical shaped nanoparticle changes their morphology to hexagonal plate shape with increase in HT temperatures. The effect of such a systematic morphological transformation of nanoparticles on magnetic and microwave absorption properties were estimated in X band
Leukocyte Classification using Adaptive Neuro-Fuzzy Inference System in Microscopic Blood Images
No full textMicroscopic pathology is still a meticulous and biased task for hematologist, which leads to the misclassification of cells and vagueness prediction of abnormal cells due to variability in the morphological structure of leukocytes. Therefore, to enhance the detection precision and diminishing the time factor, an automatic classification system for leukocytes has been proposed. In routine clinical practice, expert hematologists observed that the nucleus plays a crucial role in the identification of the blood disorders. Accordingly, in this work, the localization of leukocyte nucleus is performed by using Chan–Vase level-set method for the design of a classification framework that differentiates between four classes of the leukocytes, i.e., eosinophils, polymorphs, monocytes and lymphocytes based on the nucleus. A dataset consisting of 162 leukocyte microscopic images is used. The images in the dataset are classified on the basis of texture, shape and color features. The feature selection method based on the linguistic hedge is applied on evaluated feature space of 92. The selected features are fed to an adaptive neuro-fuzzy classifier for the classification. The proposed framework obtained an accuracy of 98.7% after applying the adaptive neuro-fuzzy classification on selected 46 informative features. The correlation of best features and data extorted from the different microscopic images may yield a dramatic increase in diagnostic consistency in clinical pathology. The results obtained by utilization of selected optimal features and adaptive neuro-fuzzy classification system indicate that it can be routinely used in clinical environment for differential diagnosis between different classes of leukocytes
Synthesis and Characterization of Carbon Nanotubes Doped Hydroxyapatite Nanoceramic for Orthopedic Applications
No full textNano-sized bioceramic hydroxyapatite (HAp) reinforced with carbon nanotubes (CNT) is synthesized using the sol–gel technique with phosphoric acid and calcium nitrate tetrahydrate as a phosphorous and calcium precursor, respectively. The ‘as synthesized’ nanocomposite powder is characterized for phase and structural analysis using X-ray diffractometry, FTIR and Raman spectroscopy. The morphological analysis of HAp/CNT nanocomposite is done using field emission scanning electron microscopy. The tribological properties including wear rate and coefficient of friction are done by coating HAp and HAp/CNT nanocomposite on implant material (SS 316L) using spin coating technique. The wear is reduced by 24.57% for HAp-coated SS316L and 29.6% for HAp-5% CNT-coated SS316 substrate. The addition of CNT in HAp matrix leads to lowering of the coefficient of friction
Kinematic modeling of a 7-degree of freedom spatial hybrid manipulator for medical surgery
No full textThe prime objective of this work is to deal with the kinematics of spatial hybrid manipulators. In this direction, in 1955, Denavit and Hartenberg proposed a consistent and concise method, known as D-H parameters method, to deal with kinematics of open serial chains. From literature review, it is found that D-H parameter method is widely used to model manipulators consisting of lower pairs. However, the method leads to ambiguities when applied to closed-loop, tree-like and hybrid manipulators. Furthermore, in the dearth of any direct method to model closed-loop, tree-like and hybrid manipulators, revisions of this method have been proposed from time-to-time by different researchers. One such kind of revision using the concept of dummy frames has successfully been proposed and implemented by the authors on spatial hybrid manipulators. In that work, authors have addressed the orientational inconsistency of the D-H parameter method, restricted to body-attached frames only. In the current work, the condition of body-attached frames is relaxed and spatial frame attachment is considered to derive the kinematic model of a 7-degree of freedom spatial hybrid robotic arm, along with the development of closed-loop constraints. The validation of the new kinematic model has been performed with the help of a prototype of this 7-degree of freedom arm, which is being developed at Council of Scientific & Industrial Research-Central Scientific Instruments Organisation Chandigarh to aid the surgeon during a medical surgical task. Furthermore, the developed kinematic model is used to develop the first column of the Jacobian matrix, which helps in providing the estimate of the tip velocity of the 7-degree of freedom manipulator when the first joint velocity is known