Sagar Maji

Microfluidic-integrated biosensors: Prospects for point-of-care diagnostics

There is a growing demand to integrate biosensors with microfluidics to provide miniaturized platforms with many favorable properties, such as reduced sample volume, decreased processing time, low cost analysis and low reagent consumption. These microfluidics‐integrated biosensors would also have numerous advantages such as laminar flow, minimal handling of hazardous materials, multiple sample detection in parallel, portability and versatility in design. Microfluidics involves the science and technology of manipulation of fluids at the micro‐ to nano‐liter level. It is predicted that combining biosensors with microfluidic chips will yield enhanced analytical capability, and widen the possibilities for applications in clinical diagnostics. The recent developments in microfluidics have helped researchers working in industries and educational institutes to adopt some of these platforms for point‐of‐care (POC) diagnostics. This review focuses on the latest advancements in the fields of microfluidic biosensing technologies, and on the challenges and possible solutions for translation of this technology for POC diagnostic applications. We also discuss the fabrication techniques required for developing microfluidic‐integrated biosensors, recently reported biomarkers, and the prospects of POC diagnostics in the medical industry.

Nanostructured zirconia decorated reduced graphene oxide based efficient biosensing platform for non-invasive oral cancer detection

We report results of the studies relating to fabrication of a non-invasive, label-free and an efficient biosensing platform for detection of the oral cancer biomarker (CYFRA-21-1). One step hydrothermal process was used for uniform decoration of nanostructured zirconia (average particle size 13 nm) on reduced graphene oxide (ZrO2-RGO) to avoid coagulation of the zirconia nanoparticles and to obtain enhanced electrochemical performance of ZrO2-RGO nanocomposite based biosensor. Further, ZrO2-RGO has been functionalized using 3-aminopropyl triethoxy saline (APTES) and electrophoretically deposited on the indium tin oxide coated glass substrate at a low DC potential.The APTES/ZrO2-RGO/ITO electrode exhibits improved heterogeneous electron transfer (more than two times) with respect to that of the APTES/ZrO2/ITO electrode indicating faster electron transfer kinetics. The -NH2 containing APTES/ZrO2-RGO/ITO platform is further biofunctionalized with anti-CYFRA-21-1. The structural and morphological investigations of the ZrO2-RGO based biosensing platform have been accomplished using X-ray diffraction (XRD), electrochemical, transmission electron microscopy (TEM), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FT-IR) studies. This immunosensor exhibits a wider linear detection range (2-22 ng mL(-1)), excellent sensitivity (0.756 µA mL ng(-1)) and a remarkable lower detection limit of 0.122 ng mL(-1). The observed results have been validated via enzyme linked immunosorbent assay (ELISA).

A biocompatible serine functionalized nanostructured zirconia based biosensing platform for non-invasive oral cancer detection

We report results of studies relating to the fabrication of nontoxic, biocompatible serine functionalized nanostructured zirconia (serine/nZrO2) for oral cancer detection. The hydrothermally synthesized ZrO2 nanoparticles (∼4.5 nm) have been characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The cytotoxicity studies of serine/nZrO2 carried out using MTT assay on the HEK 293 human cell line reveal biocompatibility of the serine/nZrO2. The serine functionalized nZrO2 are electrophoretically deposited onto a hydrolysed indium tin oxide (ITO) coated glass electrode (serine/nZrO2/ITO). Furthermore, monoclonal antibodies (anti-CYFRA-21-1) were covalently immobilized onto the serine/nZrO2/ITO electrode and BSA was been used for blocking of the non-specific binding sites. The fabricated BSA/anti-CYFRA-21-1/serine/nZrO2/ITO immunoelectrode was used for label free, non-invasive and efficient detection of an oral cancer biomarker (CYFRA-21-1). The electrochemical response studies of this immunoelectrode exihibited a wider linear detection range (0.01–29 ng mL−1) with a remarkable detection limit (0.01 ng mL−1) and a quick response time (6 min) for detection of the CYFRA-21-1 antigen. The results of validation studies conducted on the fabricated immunoelectrode (BSA/anti-CYFRA-21-1/serine/nZrO2/ITO) using saliva samples of oral cancer patients indicate a good agreement with the results obtained via enzyme linked immunosorbent assay (ELISA).

Long-term versus short-term noise monitoring: Strategies and implications in India

The paper investigates the accuracy of short-term noise monitoring strategies w.r.t. the long-term noise monitoring. The difference in short-term strategies from the annual average representative values obtained from yearly noise monitoring data is quantified as error. Long-term continuous noise monitoring data in terms of monthly averages for 35 locations spread over 7 major cities of India is analyzed. The analysis shows that the error of _3 dBA from annual equivalent level is calculated with 95% probability for LDay (06-22 h) and LNight (22-06 h) value by adopting 1 month noise monitoring strategy. For higher accuracy, the random 2 months strategy is recommended, whereby an error of _2 dBA is achieved with a probability higher than 90%. The study reveals that short-term noise monitoring strategy followed gives a reliable accuracy levels w.r.t. continuous long-term monitoring and thus offers a best practicable and economical option (BPEO) for noise mapping of larger parts of the country.

On Analyzing the Correlations and Implications of Single-Number Quantities for Rating Airborne Sound Insulation in the Frequency Range 50 Hz to 5 kHz

The paper presents the implications and correlations of single-number quantities (SNQ) proposed by Scholl et al., 2011 calculated from the sound transmission loss measurements conducted in the extended frequency range of 50 Hz to 5 kHz. Although the new SNQ proposed in ISO 16717 have been withdrawn, yet these SNQ may appear in future which has prompted the present analysis and discussion. The present study contributes to the ongoing debate on newly proposed SNQ by establishing their implications and correlations and the shift in numerical values in transition from old to proposed SNQ.

Design Considerations for Enhancing Sound Insulation Characteristics of Window Glazing for Traffic Noise Abatement

The work reviews the design aspects related to window glazing constructions for combating the low frequency noise radiated by vehicular traffic and assimilates them in a cause and effect diagram. An experimental investigation is conducted in Reverberation chambers on various window glazing configurations to ascertain the performance of various parameters viz., depth of air space and effect of lamination on sound insulation characteristics. A pronounced dip attributed to mass-air-mass resonance consistent with theoretical formulation is observed when air gap is less that 30 mm in double glazings. Significant increase in (Rw+Ctr) value is observed in a sandwich constructions with 85 mm air gap or in sandwich constructions with either one double glazing or both are double.

Biodiesel production from microalgae oil through conventional and ultrasonic methods

ABSTRACT In the present study, the oil extracted from the microalga Neochloris oleoabundans was used for producing biodiesel. The viscosity of microalgal oil was very high so transesterification was done by an ultrasonic method and a simple basic method. Free fatty acid content in oil was found high so a two-step transesterification reaction was used. Maximum yield of algal oil methyl ester was acquired by the ultrasonic method (98%) with improved physicochemical characteristics, whereas the biodiesel yield obtained by simple transesterification process was low (91%). The maximum oil content in N. oleoabundans was found to be 42% and major fatty acids include palmitic acid, oleic acid, and linoleic acid. Finally, it was conferred that the ultrasonic-assisted transesterification method is the best technique for biodiesel production from microalgal oil.

Comparison of ARIMA and ANN approaches in time-series predictions of traffic noise

The paper analyzes the long-term noise monitoring data using autoregressive integrated moving averages (ARIMA) modeling technique and artificial neural networks (ANNs) methodology. Box-Jenkins ARIMA and ANN approach have been utilized to simulate daily equivalent LDay (06-22h) and LNight (22-06h) in A and C weightings for a period of 1 year. The forecasting performance is ascertained using the statistical tests. The work draws a comparison of time-series ARIMA and ANN approach for ascertaining their suitability for traffic noise modeling and forecasting. It is observed that the artificial neural network (ANN) models outperform the ARIMA models so developed. The pattern of ARIMAf orecasting models is directional and as such the time-series predictive model utilizing ANN approach has demonstrated superior performance over the ARIMA model.

Applications of AutoRegressive Integrated Moving Average (ARIMA) approach in time-series prediction of traffic noise pollution

The paper analyzes the long-term noise monitoring data using the AutoRegressive Integrated Moving Average (ARIMA) modeling technique. Box-Jenkins ARIMA approach has been adapted to simulate the daily mean LDay (06-22 h) and LNight (22-06 h) in A- and C-weightings in conjunction with single-noise metrics, day-night average sound level (DNL) for a period of 6 months. The autocorrelation function (ACF) and partial autocorrelation function (PACF) have been obtained to find suitable orders of autoregressive (p) and moving average (q) parameters for ARIMA (p, d, q) models so developed for all the single-noise metrics. The ARIMA models, namely, ARIMA(0,0,14), ARIMA(0,1,1), ARIMA(7,0,0), ARIMA(1,0,0) and ARIMA(0,1,14), have been developed as the most suitable for simulating and forecasting the daily mean LDay dBA, LNight dBA, LDay dBC, LNight dBC, and day-night average sound level (DNL) respectively. The performance of the model so developed is ascertained using the statistical tests. The work reveals that the ARIMA approach is reliable for time-series modeling of traffic noise levels.

Suppression of pool fire in a large enclosure with water mist

This paper reports the results of an experimental study of suppression of pool fires in enclosed spaces using water mist. The main objective of the present study is to understand the mechanisms responsible for the suppression of pool fires using water mists. Experiments were conducted in a large compartment with n-heptane pool fires of different heat release rates. The temperature variations in the compartment were measured using K-type thermocouples fixed at two locations. A multi gas analyzer was used to measure gas concentrations. The test results indicate that the water mist suppresses the diffusion flame in an enclosed space mainly through evaporating cooling and oxygen displacement by water vapors, resulting in inefficient combustion. The fire suppression time decreases with a decrease in droplet diameter. It is much easier to suppress a larger fire due to faster rates of evaporation of water droplets and therefore, the total mist requirement decreases with an increase in the fire size. The results of this study can find application in the design of water mist based fire fighting systems for indoor fires.