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Synthesis and Characterization of Silica-Coated Silver Nanoprobe for Paraoxon pesticide Detection
No full textMetal enhanced fluorescence assay-based sensitive detection of a neurotoxic organophosphates pesticide, Paraoxon, is reported. The experimental approach involves the bio-interfacing of organophosphorus hydrolase with a high quantum yield fluorophore, pyranine (8-hydroxyl pyrene-1,3,6-trisulfonic acid trisodium salt), followed by the conjugation of the OPH-pyranine derivative with silica-coated silver nanoparticles (Ag NPs). The above bio-nanoprobe was used for the analysis of the organophosphate pesticide, wherein the induced hydrolysis of the pesticide cause the decrease in pH in the vicinity. An excitation light of 460 nm wavelength was used to monitor the changes in the resulting emission (at 510 nm) with respect to the changing pesticide concentrations (1–100 ppb). The introduction of the silica-coated AgNPs into the nanoprobe system was observed to deliver metal enhanced effect, leading to almost10-fold intensification of the fluorescence signal. The enhanced fluorescence assay format offers linear detection of Paraoxon in the concentration range of 1–100 ng mL−1 with the limit of detection 1 ng mL−1 (1 ppb)
Correlation between Effects of Cushion Density and Principle Components of Ground Reaction Forces for Variable Gait
No full textEffects of variable cushion densities on human gait are estimated by analyzing principle components of Ground Reaction Force (GRF) which includes Vertical Ground Reaction Forces (VGRF), Moments (M) and Center of Pressure (COP). This biomechanics study aims to identify design and parameters for quantification of a prosthetic foot. VGRF is important to analyze dynamics of human gait and predict the quality of prosthetic foot, and more accurate estimation is possible by inclusion of lower limb moments and COP. Experimental GRF data of human gait with cushion pads of different densities under heal area is acquired through force platform. Recorded gait data is correlated for variation in VGRF, moments and COP with respect to variation in Cushion Densities (CD). It is observed that VGRF (FZ1, FZ3) and Moment (M1) decrease significantly with the increase in cushion densities. Similarly, VGRF (Fz2), Moment (M2, M3) and COP increase with the increase in cushion densities and that VGRF reduces for walking at normal speed with added cushion heel as compared to bare foot (without cushion pads) walking
RFID-based navigation of autonomous patient vehicle for hospital management
No full textIn recent years, there has been great interest in the emerging field of human assistive devices. Changing lifestyle and demography are two major factors demanding quality healthcare for the Indian population, and technological intervention is the need of the hour. Precise localisation techniques have been the interest of study for decades. Various navigation techniques like global positioning system (GPS), infra red techniques (IR), etc., have been developed. Radio frequency-based localisation technology, RFID, is being used for the precise location inside buildings and operates without line of sight. It uses contactless RFID tags and readers for data transfer. ARDUINO-UNO open system hardware is used to support microcontroller. Using RFID, patient vehicle can be guided remotely and programmed to reach its destination by viewing the stored map. Also, RFID can be used to tag hospital assets and equipment to increase their visibility. Hospital administration will be immensely benefited with such assistive device, as they will not have to depend on extra caretakers
Optical fiber antenna generating spiral beam shapes
No full textA simple method is proposed here to generate vortex beam and spiral intensity patterns from a Gaussian source. It uses a special type of optical fiber antenna of aperture ∼80 nm having naturally grown surface curvature along its length. The antenna converts linearly polarized Gaussian beam into a beam with spiral intensity patterns. The experimentally obtained spiral patterns with single and double spiral arms manifest the orbital angular momentum, l = ±1, 2, carried by the output beam. Such beam can be very useful for optical tweezer, metal machining, and similar applications
Fabrication of λ/2 phase step mirror for CO2 laser resonator using diamond turning
No full textA stable optical resonator comprising a spherical rear mirror with a phase step of λ/2 at its center and a flat output coupler promises to produce a beam with very low diffraction. Based on this premise, a phase step mirror is fabricated on oxygen-free high-conductivity copper substrate using single-point diamond turning method for use in kilowatt-class CO2 laser. The fabrication technique and subsequent metrology measurements of the optical component, e.g., surface profile error and surface finish, are discussed
Luminescent nanocrystal metal organic framework based biosensor for molecular recognition
No full textA nanocrystal metal organic framework (NMOF1) has been investigated for molecular recognition. NMOF1 {[Cd(atc)(H2O)2]n} has been synthesized by the reaction of Cd(II) ions with the sodium salt of ‘atc’ (‘atc’ = 2-aminoterephthalic acid) in aqueous medium at room temperature. Pendent single bondCOOH group of the organic linker was activated using EDC [(1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide] intermediated organic reaction, followed by the bioconjugation of NMOF1 with anti-BSA (anti-bovine serum albumin). NMOF1/anti-BSA complex has been used for the sensing of BSA (bovine serum albumin) based on the fluorescence quenching phenomena. Estimated limit of detection of the proposed molecular probe is 7 mg/mL
Translocation and Toxicity of Docetaxel Multi-Walled Carbon Nanotube Conjugates in Mammalian Breast Cancer Cells
No full textMulti-walled-carbon nanotubes (MWNTs) are widely explored as carriers for drug delivery due to their facile transport through cellular membranes and are reportedly found to be effective against cancer. In the present study, we have evaluated cellular uptake of Docetaxel (DTX) conjugated MWNTs from human breast cancer cells (MCF-7 and MDA-mb-231) and have provided primary results on cytotoxicity of the same. Efficient internalization of the drug conjugate (DTX-MWNTs) inside the cell was corroborated with the help of confocal microscopy, transmission electron microscopy and flow cytometry. The comparison of cytotoxicity of the conjugate and DTX was done by MTT assay. Results of the study indicated increased efficacy of the conjugates over the drug in terms of their cytotoxicity. It was observed that such conjugation of drug to MWNTs can be explored as a strategy to improve therapeutic index of cytotoxic drugs such as DTX and thereby enriching cancer therapies of coming time
Phosphinic acid functionalized carbon nanotubes for sensitive and selective sensing of chromium(VI)
No full textSingle-walled carbon nanotubes (SWCNTs) have been functionalized with a phosphinic acid derivative 'bis(2,4,4-trimethylpentyl) phosphinic acid' (PA/d). It has been achieved by treating the chlorinated SWCNTs with PA/d at 80°C. Successful functionalization and different nanomaterial properties have been investigated by UV-vis-NIR, FTIR, Raman spectroscopy, AFM and FE-SEM. PA/d conjugated SWCNTs (CNT-PA) are dispersible in some common organic solvents, e.g. CH2Cl2, DMF, CHCl3, and THF. The 'CNT-PA' complex was spin-casted on boron doped silicon wafer. Thus fabricated sensing electrode is demonstrated for sensitive and selective electrochemical sensing of chromium(VI) ions. A linear response is obtained over a wide range of Cr(VI) concentration (0.01-10 ppb). The sensor's sensitivity and the limit of detection are observed to be 35 ± 4 nA/ppb and 0.01 ppb, respectively. The practical utility of the proposed sensor is demonstrated by determining the Cr(VI) concentration in an industrial effluent sample and an underground water sample
Optimization and characterization of pulsed electric field parameters for extraction of quercetin and ellagic acid in emblica officinalis juice
No full textA novel study has been optimized for the application of pulsed electric field (PEF) treatment (varying from 18 to 24 kV cm−1 for the duration 300–1,000 µs) on fresh emblica juice for extracting quercetin & ellagic acid which are considered as the major secondary metabolites in plant based foods. HPLC–PDA studies showed substantial increase (p < 0.05) in the PEF extracted levels of above metabolites in herb juice. It can be attributed to PEF induced vibrational disruption which increases the metabolic stress leading to emergence of these compounds. Both Raman and FTIR characterization, confirmed the presence of these in emblica juice. Electric field strength of 22 kV cm−1 was found to be optimum, where maximum cell disintegration index (0.79) was achieved during treatment time of 500 µs, which enhanced the amount of quercetin to about ninefolds and ellagic acid to about twofolds respectively, in comparison to untreated and thermally treated juice sample. However, a reverse trend was observed in thermally treated juice where degradation of the compounds (p < 0.05) was detected. Thus, PEF can be considered as a viable medium for extracting intracellular metabolites, thereby incrementing the functional potential of emblica juice
Pyrolysis coupled pulse oxygen incineration for disposal of hazardous chromium impregnated fine particulate solid waste generated from leather industry
No full textThis paper focuses on characterization and pyrolysis coupled pulse oxygen incineration (PyPOI) of hazardous chromium (Cr3+) impregnated microfined solid particulate matter (MSPM) generated from leather industry. The PyPOI process yielded gaseous products, 47.46%; condensate oil, 34.20%; and remnant ash 18.34%. The energy profile of MSPM under PyPOI process was studied and compared with pyrolysis process. The energy released under varied mass loading of MSPM through PyPOI process was 4140 kJ, 9468 kJ, 12,816 kJ and 13,968 kJ for 0.5 kg, 1.0 kg, 1.5 kg and 2.0 kg respectively. The constituents of pyrolytic gases were CO, CO2, CxHy, O2, SO2, NOx and H2. The MSPM, remnant ash and distillate were characterized using TGA, FT-IR and SEM/EDX. The TGA of remnant ash of MSPM confirmed that about 80% of the material was thermally stable up to 800 °C. Maximum weight loss of MSPM was achieved under PyPOI process using pulse oxygen supplied at the rate of 1.75 g/min inside the reactor vessel in the temperature range from 600 °C to 800 °C. The SEM images proved that unburnt carbon slabs were obtained under pyrolysis while crumbled carbon flakes were obtained under PyPOI process. FT-IR of condensate oil confirmed the presence of aromatic nitrogen compounds. The hexavalent chromium (Cr6+) content of remnant ash under PyPOI process was 0.028 ± 0.006 mg/kg which was well within the limit of disposal (4 mg/kg)