654 research outputs found
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MOF–Bacteriophage Biosensor for Highly Sensitive and Specific Detection of Staphylococcus aureus
No full textTo produce a sensitive and specific biosensor for Staphylococcus aureus, bacteriophages have been interfaced with a water-dispersible and environmentally stable metal-organic framework (MOF), NH2-MIL-53(Fe). The conjugation of the MOF with bacteriophages has been achieved through the use of glutaraldehyde as cross-linker. Highly sensitive detection of S. aureus in both synthetic and real samples was realized by the proposed MOF-bacteriophage biosensor based on the photoluminescence quenching phenomena: limit of detection (31 CFU/mL) and range of detection (40 to 4 × 108 CFU/mL). This is the first report exploiting the use of an MOF-bacteriophage complex for the biosensing of S. aureus. The results of our study highlight that the proposed biosensor is more sensitive than most of the previous methods while exhibiting some advanced features like specificity, regenerability, extended range of linear detection, and stability for long-term storage (even at room temperature)
Fluorescent nanobiosensors for the targeted detection of foodborne bacteria
No full textFoodborne diseases caused by bacterial pathogens are severe threats to human health. Conventional culture based microbiologic methods for the analysis of bacterial contamination in food products are laborious, time consuming and require specific skills. Immunologic and polymerase chain reaction (PCR)-based molecular methods are also costly, lack specificity, and may yield false results. As outlined in this review, fluorescent nanobiosensors have now become effective alternative tools for rapid and routine detection of foodborne bacteria. We provide an overview of the use of different fluorescent nanomaterials in the development of nanobiosensors with special emphasis on underlying detection principles, sensitivity, specificity, and their capability of multiplexed analysis. In summary, the diverse nanomaterials used for bacterial detection are critically analyzed with respect to their advantages and limitations for future applications in the diagnosis of foodborne bacteri
Efficient photocatalytic and photovoltaic applications with nanocomposites between CdTe QDs and an NTU-9 MOF
No full textA new photoactive hybrid nanostructure formed through an integration of quantum dots (QDs) and metal organic frameworks (MOFs) has been explored and assessed for its photocatalytic and photovoltaic performance. To this end, the QD–MOF nanocomposite was synthesized by mixing CdTe QDs during the formation of a titanium-based MOF ‘NTU-9,’ with titanium isopropoxide as a metal source and 2,5-dihydroxyterephthalic acid (H4DOBDC) as an organic ligand. The successful formation of this nanocomposite is verified using various microscopic and spectroscopic techniques. Because the CdTe/NTU-9 composite exhibited a considerably broadened light absorption profile, it has achieved a rapid (30 min) and visible light-driven photocatalytic degradation (>95%) of rhodamine 6G. Further, when this composite is tested as a photoanode material in a QD-sensitized solar cell (QD-DSSC), its power conversion efficiency improved by approximately 1.5% relative to the raw QD form. Accordingly, CdTe/NTU-9 is demonstrated as a potential candidate for future applications in photocatalysis and DSSCs. The key features of the proposed nanocomposite include improved light absorption, sub-micron scale processing, chemical and thermal stability, easier regeneration, and better photocatalytic/photovoltaic characteristics
A novel CdTe/Eu-MOF photoanode for application in quantum dot-sensitized solar cell to improve power conversion efficiency
No full textThe quantum dots (QDs) and metal-organic frameworks (MOFs) have emerged as the efficient nanomaterials for light harvesting, photocatalysis, and photovoltaic applications. Here, the application of a composite of CdTe QDs with a europium-MOF was demonstrated as a novel photoanode to achieve the improvement in the short circuit current density from 19.8 (CdTe QD) to 28.45 mA/cm2 (CdTe QD/Eu-MOF). So does power conversion efficiency (PCE) between the former (1.67%) and the latter (3.02%). This 1.35% of difference (or absolute enhancement) in the PCE can be attributed to an enhanced surface area and increased photon absorption capacity
Molybdenum disulfide quantum dot based highly sensitive impedimetric immunoassay for prostate specific antigen
No full textThis work reports on the synthesis of molybdenum disulfide quantum dots (MoS2-QDs) from pre-exfoliated MoS2 nanosheets. After a thorough characterization, the MoS2-QDs were assembled onto screen-printed carbon electrodes, followed by the physical adsorption of antibodies against the prostate-specific antigen (PSA) to form a bioelectrode. Because of the hydrophobic nature of the QDs, they are favorable for the hydrophobic interaction with the antibodies. Based on cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques, the bioelectrode was employed for the detection of PSA using hexacyanoferrate as the redox probe. The electrode yielded an optimum CV response of PSA in the range of 0.1 pg·mL−1 to 10 ng·mL−1 (scan rate: 0.05 mVs−1). The performance improved significantly when EIS was applied (response range: 0.01 pg·mL−1 to 200 ng·mL−1; limit of detection: 0.01 pg·mL−1). The feasibility of the immunoassay was demonstrated by successfully analyzing PSA in serum samples based on the standard addition method. A near 100% recovery of PSA from the serum samples supports the possible practical viability of the procedure. The immunoassay highlights a number of advantageous features such as convenient attachment of antibodies over the electrode surface and broad range of PSA detection with the successful demonstration with real serum samples
A systematic review and meta-analysis of voltammetric and optical techniques for inorganic selenium determination in water
No full textSelenium, a metalloid, commonly known for its essentiality has emerged out as a water pollutant of concern for environmentalist due to its presence in natural water resources above the permissible limit. The high level of selenium in the environment poses severe health and ecosystem threats, therefore, its monitoring in water is of paramount concern. The present contribution summarizes and critically analyzes the field promising techniques, in particular, voltammetry and optical approach, for selenium quantification in water. The role of sensor material (organic fluorophores, colorimetric dyes and quantum dots), electrode surface modifiers (Hg, Bi, polymers, nanomaterials, etc.), chelators, etc., to overcome various challenges and achieve better sensor performance in terms of detection limit, range, reproducibility, stability, selectivity, sensitivity, and so forth are critically discussed. To end with, the possible future developments are discussed towards the realization of a cost-effective & field deployable monitoring device for on-site selenium analysis
Optical Fiber Sensor With ZnO Hierarchical Nano-Structures Grown on Electrospun ZnO Mat Base on the Sensor for Trace Level Detection of Volatile Amines
No full textThis article demonstrates an optical fiber sensor probe coated with hierarchical nanostructures of zinc oxide (ZnO) for trace level detection of volatile amines. The nanostructure is grown by hydrothermal process on a multimode optical fiber probe coated with ZnO nanofibrous mat prepared by electrospinning technique. The high surface area of the hierarchical structures facilitated diffusion of amines, which, on interaction with ZnO surface, changes the effective refractive index of the optical fiber probe. The modulation of the transmitted intensity through the optical sensor probe in presence of the target analyte is monitored for sensing the amine. An increase in absorbance is observed in proportion to amine concentrations with the emergence of a broad peak at around 500 nm. The sensor is able to detect as low as 25 ppb of different volatile amines such as ammonia, triethylamine, aniline, and ethylenediamine with responses of 1%, 0.65%, 0.75%, and 0.5%, respectively. The sensor is further demonstrated for detection of volatile amines released during protein degradation in salmon fish to show its usability for real time applications
Computer assisted classification framework for prediction of acute lymphoblastic and acute myeloblastic leukemia
No full textHematological malignancies i.e. acute lymphoid leukemia and acute myeloid leukemia are the types of blood cancer that can affect blood, bone marrow, lymphatic system and are the major contributors to cancer deaths. In present work, an attempt has been made to design a CAC (computer aided classification system) for diagnosis of myeloid and lymphoid cells and their FAB (French, American, and British) characterization. The proposed technique improves the AML and ALL diagnostic accuracy by analyzing color, morphological and textural features from the blood image using image processing and to assist in the development of a computer-aided screening of AML and ALL. This paper endeavors at proposing a quantitative microscopic approach toward the discrimination of malignant from normal in stained blood smear. The proposed technique firstly segments the nucleus from the leukocyte cell background and then computes features for each segmented nucleus. A total of 331 geometrical, chromatic and texture features are computed. A genetic algorithm using support vector machine (SVM) classifier is used to optimize the feature space. Based on optimized feature space, an SVM classifier with various kernel functions is used to eradicate noisy objects like overlapped cells, stain fragments, and other kinds of background noises. The significance of the proposed method is tested using 331 features on 420 microscopic blood images acquired from the online repository provided by the American society of hematology. The results confirmed the viability or potential of using a computer aided classification method to reinstate the monotonous and the reader-dependent diagnostic methods
Multiple Model Adaptive Complementary Filter for Attitude Estimation
No full textAttitude estimation plays a major role in the autonomy of unmanned aerial vehicles and requires fusion of different sensor measurements. This paper describes an adaptive estimation scheme in which the weight parameter for the complementary filter (CF) is varied over time. The adaptive mechanism proposed here is inspired from the multiple model adaptive estimation (MMAE) scheme used for varying noise parameters in the Kalman filter structure. In this paper, the linear complementary filters are used as elementary blocks in the MMAE structure and their weights are modified probabilistically to obtain an accurate orientation estimate. It avoids the problem of manual selection of weight factor for complementary filter and provides a robust orientation estimate against varying system dynamics. The proposed MMAE based adaptive CF scheme is modular in nature and is dependent on the residual error between estimated and the measured orientation angle. It is applied on the real world datasets logged from inertial sensors and the performance of MMAE based CF structure is found to work promisingly as compared to the non-linear complementary filter versions and the extended Kalman filter framework
Effectiveness of virtual reality rehabilitation for children and adolescents with cerebral palsy: an updated evidence-based systematic review
No full textBackground
The use of virtual reality systems in the motor rehabilitation of children with cerebral palsy is new, and thus the scientific evidence for its effectiveness needs to be evaluated through a systematic review.
Objective
To provide updated evidence-based guidance for virtual reality rehabilitation in sensory and functional motor skills of children and adolescents with cerebral palsy.
Data sources
PubMed, PEDro, Web of Science, OTseeker, PsycINFO and Cochrane Library were searched from their earliest records up to 1 June, 2016.
Study selection
Two reviewers applied the population intervention comparison outcome (PICO) question to screen the studies for this review.
Data extraction
Information on study design, subjects, intervention, outcome measures and efficacy results were extracted into a pilot-tested form. Method quality was assessed independently by two reviewers using the Downs and Black checklist.
Data synthesis
Thirty-one studies included 369 participants in total. Best evidence synthesis was applied to summarize the outcomes, which were grouped according to International Classification of Functioning, Disability and Health. Moderate evidence was found for balance and overall motor development. The evidence is still limited for other motor skills.
Conclusions
This review uncovered additional literature showing moderate evidence that virtual reality rehabilitation is a promising intervention to improve balance and motor skills in children and adolescents with cerebral palsy. The technique is growing, so long-term follow-up and further research are required to determine its exact place in the management of cerebral palsy