Competitive Impedance Spectroscopy in a Schottky-Contacted ZnO Nanorod Structure for Ultrasensitive and Specific Biosensing in a Physiological Analyte.

To enable detection and discovery of biomarkers, development of label-free, ultrasensitive, and specific sensors is the need of the hour. For addressing this requirement, here, a Schottky-contacted ZnO nanorod biosensor has been demonstrated, which explores the interplay between Schottky junction capacitance and solution resistance, resulting in an interesting sensing principle of competitive impedance spectroscopy. When the transition of dominating impedance occurs from solution resistance to junction capacitance, a notch or a peak appears in the impedance response at a particular frequency (referred to as the corner frequency) depending on the charge of the target molecule. The appearance of the peak or notch acts like an electronic label for selectivity since it is visible only for target molecules even at ultralow concentrations in the physiological analyte, where the magnitude of impedance change overlaps with that for nonspecific molecules. This phenomenon has been successfully applied for the positively charged vascular endothelial growth factor (VEGF) and the negatively charged hepatitis B surface antigen (HBsAg), where the shifts in the higher corner frequencies for 1 aM concentration of the target molecules have been observed to be more than 3 times the changes in the impedance magnitude. Further, the area of the ZnO nanorods was segmented into two zones corresponding to the lower and higher concentration regimes, thereby expanding the dynamic range. To summarize, an ultralow detection limit of 1 aM with a dynamic range up to 1 pM was achieved for VEGF and HBsAg, which is 4 orders of magnitude and 20 times lower than their most sensitive label-free reports, respectively.

A review on nanopores based protein sensing in complex analyte.

Solid-state nanopore has the ability to detect proteins at a single-molecule level with its high sensitivity, high-throughput, and low cost. Improvements in fabrication, functionalization, and characterization of solid-state nanopores keep evolving. Various analytical methods targeted towards diagnostic applications using nanopore-based devices are appearing. This review article provides an overview of recent progress in the field of solid-state and biological nanopores for protein detection in a complex analyte. The advantages and challenges involved in nanopore sensing have been discussed. Further, the review surpasses the steady-state resistive pulse techniques of sensing and incorporate transient variations in the nanopore conductance. Application of the power spectral density of these fluctuations toward sensing has been highlighted with importance on reducing the detection limit in a complex environment. Lastly, the current problems and future perspectives have been discussed with a perspective to increase nanopores performance towards diagnostic applications in complex medium.

Stress-mediated quality of life outcomes in parents of disabled children: A case-control study.

BACKGROUND: The purpose of the present study was to resolve whether caregiving for a child with disability influences the physical and mental health of the caregivers and whether stress is related to the quality of life of the caregivers. METHODS: The Parental Stress Scale questionnaire for the assessment of parental stress and the Short Form-12 version 2 questionnaire for the assessment of physical and mental health quality of life were distributed among 69 parents of developmentally disabled children and 137 parents of healthy children (control group). Various sociodemographic factors were also included. RESULTS: A significant difference was seen between the two groups in terms of employment, presence of disabled sibling, smoking, and physical activity. Parents of developmentally disabled children had significantly higher stress levels and worse mental health-related quality of life. Overall physical health quality of life was similar between cases and controls. Stress had a negative correlation with both mental and physical health quality of life of the parents. CONCLUSION: Stress related to raising a child with disability negatively influences the parental quality of life. Stress management aiming at its prevention and reduction might be significant aspects of intervention for the improvement of the quality of life of the caregivers.

Efficacy of Lesion Sterilization and Tissue Repair in Primary Tooth with Internal Resorption: A Case Series.

Lesion sterilization and tissue repair (LSTR) treatment involves the use of a triple antibiotic mixture in a suitable vehicle, which is used to disinfect root canal systems. This report highlights three cases where LSTR therapy using triple antibiotic paste was attempted in primary molars exhibiting gross periradicular pathosis and internal resorption. Follow-up examinations revealed reduction of periradicular pathosis and reversal of internal resorption in all the three cases. This case series opens a perspective on the use of LSTR therapy as an alternative option to extraction in treating primary teeth with gross periradicular pathosis and internal resorption.

Performance study of chromium (VI) removal in presence of phenol in a continuous packed bed reactor by Escherichia coli isolated from East Calcutta Wetlands.

Organic pollutants, like phenol, along with heavy metals, like chromium, are present in various industrial effluents that pose serious health hazard to humans. The present study looked at removal of chromium (VI) in presence of phenol in a counter-current continuous packed bed reactor packed with E. coli cells immobilized on clay chips. The cells removed 85% of 500 mg/L of chromium (VI) from MS media containing glucose. Glucose was then replaced by 500 mg/L phenol. Temperature and pH of the MS media prior to addition of phenol were 30°C and 7, respectively. Hydraulic retention times of phenol- and chromium (VI)-containing synthetic media and air flow rates were varied to study the removal efficiency of the reactor system. Then temperature conditions of the reactor system were varied from 10°C to 50°C, the optimum being 30°C. The pH of the media was varied from pH 1 to pH 12, and the optimum pH was found to be 7. The maximum removal efficiency of 77.7% was achieved for synthetic media containing phenol and chromium (VI) in the continuous reactor system at optimized conditions, namely, hydraulic retention time at 4.44 hr, air flow rate at 2.5 lpm, temperature at 30°C, and pH at 7.