602 research outputs found
Label-Free, Highly Sensitive Electrochemical Aptasensors Using Polymer-Modified Reduced Graphene Oxide for Cardiac Biomarker Detection
Acute myocardial infarction (AMI), also recognized as a ???heart attack,??? is one leading cause of death globally, and cardiac myoglobin (cMb), an important cardiac biomarker, is used for the early assessment of AMI. This paper presents an ultrasensitive, label-free electrochemical aptamer-based sensor (aptasensor) for cMb detection using polyethylenimine (PEI)-functionalized reduced graphene oxide (PEI???rGO) thin films. PEI, a cationic polymer, was used as a reducing agent for graphene oxide (GO), providing highly positive charges on the rGO surface and allowing direct immobilization of negatively charged single-strand DNA aptamers against cMb via electrostatic interaction without any linker or coupling chemistry. The presence of cMb was detected on Mb aptamer-modified electrodes using differential pulse voltammetry via measuring the current change due to the direct electron transfer between the electrodes and cMb proteins (Fe3+/Fe2+). The limits of detection were 0.97 pg mL???1 (phosphate-buffered saline) and 2.1 pg mL???1 (10-fold-diluted human serum), with a linear behavior with logarithmic cMb concentration. The specificity and reproducibility of the aptasensors were also examined. This electrochemical aptasensor using polymer-modified rGO shows potential for the early assessment of cMb in point-of-care testing applications
In search of self-efficacy: development of a new instrument for first year Computer Science students
This study explores the changes in Computer Science (CS) studentsā self-efficacy between entering study and the end of first year of university. It aims to give course leaders insights into the everyday challenges that affect studentsā academic achievement and persistence into second year. The paper begins by proposing that the way CS is taught, the gender imbalance on CS courses, and the experience of the key transitional year into university might influence CS studentsā non-continuation. It adopts an academic buoyancy conceptualisation of resilience. Acknowledging the scarcity of instruments covering CS studentsā transition to university, the development of a new 20-item questionnaire is described, based on CS studentsā own contributions of the challenges they faced during first year. The instrument is administered twice in one session to the same cohort. Analysis of paired responses indicates a loss of confidence to overcome challenges in most aspects, particularly staying motivated to study
ANTIBACTERIAL ACTIVITY IN DIFFERENT EXTRACTS OF LANTANA CAMARA AGAINST ENTEROPATHOGENS
Medicinal use of plants is the oldest form of healthcare known to mankind. India has a rich profusion of medicinal plants and 75% of its folk population is still using herbal preparations. Present study reports about antimicrobial potentiality of Lantana camara as its leaf extracts exhibit good antimicrobial, fungicidal, insecticidal and nematicidal properties and the plant might be a novel source of antimicrobial drug. Two enteropathogens as (A) - B. subtilis (positive, obligate aerobic) and (B) - E. coli (Gram-negative, facultative anaerobic) were used for the present study. Four solvent phases viz, methanol, ethanol, acetone and aqueous were used for extraction of antimicrobial agent. The screening of antimicrobial property was done by well diffusion method. Leaves of Lantana camara showed excellent antibacterial activity in all the solvent phases used against both E. coli as well as B. subtilis. Lantana is effective against both the bacteria.The aqueous extract showed minimum ineffective antimicrobial activity against E. coli and B. subtilis, where as acetone phase showed maximum activity against B. subtilis and ethanol against E. coli as shown in the terms of maximum zone of inhibition
Common Fixed Point Theorems of Integral Type in Menger Pm Spaces
In this paper, we propose integral type common fixed point theorems in Menger spaces satisfying common property (E.A). Our results generalize several previously known results in Menger as well as metric spaces. Keywords: Menger space; Common property (E.A); weakly compatible pair of mappings and t-norm
Common fixed theorems for weakly compatible mappings via an implicit relation using the common (E.A) property in intuitionistic fuzzy metric spaces
In this chapter, we prove two common fixed theorems for weakly compatible mappings via an implicit relation using the common (E.A) property in intuitionistic fuzzy metric space
A Common Fixed Point Theorems in Menger Space using Occationally Weakly Compatible Mappings
In this paper we have improved the result of Saurabh Manro [7] by using the concept of occasionally weakly compatible Maps and proved some results on fixed points in menger space. Key words: Menger space, Common fixed point, occasionally weakly compatible mappings
A Design of Crown Square Fractal Antenna Using Transmission Line Feed
The paper presents the designs of a crown square fractal antenna. The propounded antenna is designed on 1.6mm thick FR4 glass proxy substrate with dielectric constant Er of 4.4 and is fed by transmission line. The proposed antenna design helps in reducing the metal USAge, save cost and provides good reflection coefficient and good VSWR. Performance of proposed antenna has been analyzed in terms of return loss, VSWR, input impedance, gain, and bandwidth in the 1 GHz to 7GHz frequency range. The proposed antenna provides an impedance bandwidth of 45 % around the resonant frequency of 0.5575 GHz and good return lossof -36.44
Cost-Effective and Handmade Paper-Based Immunosensing Device for Electrochemical Detection of Influenza Virus
Although many studies concerning the detection of influenza virus have been published, a paper-based, label-free electrochemical immunosensor has never been reported. Here, we present a cost-effective, handmade paper-based immunosensor for label-free electrochemical detection of influenza virus H1N1. This immunosensor was prepared by modifying paper with a spray of hydrophobic silica nanoparticles, and using stencil-printed electrodes. We used a glass vaporizer to spray the hydrophobic silica nanoparticles onto the paper, rendering it super-hydrophobic. The super-hydrophobicity, which is essential for this paper-based biosensor, was achieved via 30-40 spray coatings, corresponding to a 0.39-0.41 mg cm(-2) coating of nanoparticles on the paper and yielding a water contact angle of 150 degrees +/- 1 degrees. Stencil-printed carbon electrodes modified with single-walled carbon nanotubes and chitosan were employed to increase the sensitivity of the sensor, and the antibodies were immobilized via glutaraldehyde cross-linking. Differential pulse voltammetry was used to assess the sensitivity of the sensors at various virus concentrations, ranging from 10 to 10(4) PFU mL(-1), and the selectivity was assessed against MS2 bacteriophages and the influenza B viruses. These immunosensors showed good linear behaviors, improved detection times (30 min), and selectivity for the H1N1 virus with a limit of detection of 113 PFU mL(-1), which is sufficiently sensitive for rapid on-site diagnosis. The simple and inexpensive methodologies developed in this study have great potential to be used for the development of a low-cost and disposable immunosensor for detection of pathogenic microorganisms, especially in developing countries
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