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Advent of Proteomic Tools for Diagnostic Biomarker Analysis in Alzheimer's Disease
No full textLocating remedies for Alzheimer's disease (AD) has been majorly restricted by the inefficiency to establish a definitive detection model for early-stage diagnosis of pathological events. This current lapse in AD diagnosis also limits the therapeutic efficiency of the drugs, which might have been effective if given at the earlier stages of the disease. The indicated situation directs towards the burgeoned need for an effective biomarker technique that will help in early detection of AD and would be imminently useful to facilitate improved diagnosis and stimulate therapeutic trials. Till date, the major biomarkers, specifically associated with AD detection, may help in determining the early-stage AD diagnosis and identifying alterations in the cellular proteome, offering deeper insight into disease etiology. Currently existing multidisciplinary clinical diagnosis of AD is a very tedious, expensive procedure and requires highly trained and skilled professionals who are rarely available outside the specialty clinics. Mutations in amyloid precursor protein (APP) or Presenilin 1 and 2 (PSEN1 and PSEN2) are some biomarkers acting as critical checkpoints for AD diagnosis. However, the presence of some associated biomarkers in cerebrospinal fluid (CSF) such as total-Tau (tTau), phosphorylated-Tau (pTau) 181 and Amyloid-beta (A beta) 1-42 using structural or functional imaging techniques is considered for confirmatory diagnosis of AD. Furthermore, the molecular diagnosis of AD incorporates various sophisticated techniques including immuno-sensing, machine learning, nano conjugation-based detections, etc. In the current review description, we have summarized the various diagnostic approaches and their relevance in mitigating the long-standing urgency of targeted diagnostic tools for detection of AD
Ag ion implanted TiO2 photoanodes for fabrication of highly efficient and economical plasmonic dye sensitized solar cells
No full textMaterials with tunable optical and photoelectric properties are prerequisite for the development of highly stable, economical and efficient dye sensitized solar cells (DSSCs). In this direction, improved plasmonic DSSCs with comparatively higher light harvesting ability and reduced recombination of photo-generated charge carriers have been fabricated using low energy (120 KeV) Ag ion implanted TiO2 photoanodes at variable fluence. Herein, the origin of improved photovoltaic performance of Ag implanted DSSCs against conventional DSSC has been explained using UV-visible, photoluminescence and kelvin probe measurements. Further, the efficient interfacial charge transportation within Ag implanted DSSCs has been demonstrated through EIS measurements
Giant pressure sensitivity in piezo/ferro-electric ceramics
Get PDFWe report the fabrication of single-phase polycrystalline Pb0.85Bi0.10(Zr0.52Ti0.48)O-3 (PBiZT) ceramic which shows large polarization, i.e., similar to 40 mu C cm(-2) and piezoelectric coefficients similar to 130 pC N-1 and giant linear change in capacitive reactance and dielectric properties with increasing and decreasing pressure in the range of 1 kHz to 5 MHz. Nearly 70% change in dielectric constant and 56% change in capacitive reactance were obtained in the pressure range of 20-200 MPa, which makes it suitable for applications as a capacitive pressure sensor/gauge. The sensitivity of the device is calculated as 0.66 MPa-1 and 18.2 MPa-1 at 1 MHz and 5 MHz, respectively, which is the highest ever reported value so far for any bulk polycrystalline ceramic. The compressive stress of the device was tested according to the standard test method as a function of linear and volumetric strain, which yields the Young's modulus, Bulk modulus, and Poisson's ratio of the device. These values were further utilized to calculate actual stress in the sample and energy density using ANSYS software, which indicates at least four orders smaller pressure in the sample compared to the applied pressure
Graphene Quantum Dot-Sensitized ZnO-Nanorod/GaN-Nanotower Heterostructure-Based High-Performance UV Photodetectors
No full textThe fabrication of a superior-performance ultraviolet (UV) photodetector utilizing graphene quantum dots (GQDs) as a sensitization agent on a ZnO-nanorod/GaN-nanotower heterostructure has been (;QDs realized. GQD sensitization displays substantial impact on the electrical as well as the optical performance of a heterojunction UV photodetector. The GQD sensitization stimulates charge carriers in both ZnO and GaN and allows energy band alignment, which is realized by a spontaneous time-correlated transient response. The fabricated device demonstrates an excellent responsivity of 3.2 x 10(3) A/W at -6 V and displays an enhancement of similar to 265% compared to its bare counterpart. In addition, the fabricated heterostructure UV photodetector exhibits a very high external quantum efficiency of 1.2 X 10(6)%, better switching speed, and signal detection capability as low as similar to 50 fW
Highly responsive, low -bias operated SnSe 2 nanostructured thin film for trap -assisted NIR photodetector
No full textPhoto detectors are very important for operation of various opto-electronic devices, like night vision
camera, thermal imaging, remote sensing and so on. As the sizes of devices are shrinking day by day, it is
important to make photo detectors which are small, robust, stable and have good responsitivity. Also the
materials should be made from earth abundant elements and can be deposited using simple deposition
techniques. Recently, good photo-detection capabilities in the infrared as well as visible range have been
reported in metal dichalcogenides (WSe2; MoSe2; SnSe2; SnS2;WS2; MoS2; PtSe2; PdSe2 etc). SnSe2 is made
of earth abundant elements. In this study, we report IR photo response in SnSe2 nanostructured thin films
grown on soda lime glass (SLG) by thermal evaporation technique. IR (1064 nm) photo response behavior
of the film is measured at different bias voltages in 100e400 mV range in steps of 100 mV and laser
power density of 30e79 mW=cm2. The responsitivity of the device shows non-saturation of the traps
states in the device. The value of responsitivity was 0.796± 0.003 mA/W (standard deviation) at 79 mW=
cm2 laser power density and 400 mV bias voltage and the rise/decay times were 276 ms/332 ms,
respectively. It is to be noted that the photo response behavior of film was stable and reproducible even
after keeping them in atmospheric conditions for many months. This shows the potential of SnSe2 as a
suitable material for various opto-electronic applications. To the best of our knowledge, the present study
shows superior values of responstivity and response/recovery time of SnSe2 thin film on SLG substrate
Improvement in short-circuited coaxial flange for evaluating microwave superconducting properties at low temperature
Get PDFIn the present study, we have proposed an improvement in terms of the determination of S-parameters of an open flange from its characteristic impedance and propagation constant. With the help of these S-parameters, the actual reflection coefficient of YBCO films deposited on LAO substrate is obtained from the measured reflection coefficient. The surface impedance of three YBCO films is obtained in the range of few ohms in the frequency range from 1 GHz to 40 GHz. The surface resistance of the films reduces at liquid nitrogen temperature, i.e., 77 K, whereas, the surface reactance slightly increases due to kinetic inductance. The conductivity and skin depth are also determined to validate the improvement in the method
Influence of defect pairs in Ga-based ordered defect compounds: a hybrid density functional study
Get PDFIn the present paper, density functional theory (DFT) based calculations have been performed to predict the stability, electronic, and optical properties of Ga-rich ordered defect compounds (ODCs). The calculated lattice constants, bulk modulus, their pressure derivatives, and optical constants show good agreement with available experimental data. The hybrid exchange correlations functional have been considered to calculate ground state total energy and energy band gap of the material. The calculated formation energy of ODCs comes smaller than pure CuGaSe2 (CGS). Our calculated optical absorption coefficients indicate that the energy band gap of ODCs can be tuned by changing the number of donor-acceptor defect pairs (2V(cu)(-), + Ga-cu(2+)). The band offset has been calculated to understand the reason of band gap alteration while the number of defect pair changes. Our results may be helpful for other experiments to further improve the performance of ODCs
Influence of substrate nitridation on properties of GaN nanorods grown on molybdenum foil by laser molecular beam epitaxy
No full textWe studied the effect of nitridation condition of Mo foil on the properties of GaN nanorods grown by laser
molecular beam epitaxy. It is found that randomly size-distributed three-dimensional GaN islands were grown on
bare Mo foil at growth temperature of 700. Upon nitridation of Mo foil with low nitrogen plasma flux,
hexagonally-faceted inverse-tapered GaN nanorods were grown whereas tapered GaN nanorods were obtained
for Mo foil nitridated under high nitrogen plasma flux. Using wet-chemical etching process, it is deduced that the
inverse-tapered GaN nanorods have N-polarity while the tapered GaN nanorods have Ga-polarity. Optical
analysis revealed that the inverse-tapered GaN nanorods have prominent near band edge (NBE) emission peak
with negligible defect-related peaks whereas tapered GaN nanorods possess yellow luminescence peak along with
NBE emission. The control of polarity of GaN nanords on flexible metal foils by tuning pre-nitridation condition is
beneficial for futuristic nitride-based flexible opto-electronics devices
Liquid-Metal Synthesized Ultrathin SnS Layers for High-Performance Broadband Photodetectors
Get PDFAtomically thin materials face an ongoing challenge of scalability, hampering practical deployment despite their fascinating properties. Tin monosulfide (SnS), a low-cost, naturally abundant layered material with a tunable bandgap, displays properties of superior carrier mobility and large absorption coefficient at atomic thicknesses, making it attractive for electronics and optoelectronics. However, the lack of successful synthesis techniques to prepare large-area and stoichiometric atomically thin SnS layers (mainly due to the strong interlayer interactions) has prevented exploration of these properties for versatile applications. Here, SnS layers are printed with thicknesses varying from a single unit cell (0.8 nm) to multiple stacked unit cells (approximate to 1.8 nm) synthesized from metallic liquid tin, with lateral dimensions on the millimeter scale. It is reveal that these large-area SnS layers exhibit a broadband spectral response ranging from deep-ultraviolet (UV) to near-infrared (NIR) wavelengths (i.e., 280-850 nm) with fast photodetection capabilities. For single-unit-cell-thick layered SnS, the photodetectors show upto three orders of magnitude higher responsivity (927 A W-1) than commercial photodetectors at a room-temperature operating wavelength of 660 nm. This study opens a new pathway to synthesize reproduceable nanosheets of large lateral sizes for broadband, high-performance photodetectors. It also provides important technological implications for scalable applications in integrated optoelectronic circuits, sensing, and biomedical imaging
Mechanism of visible-light-driven photocatalytic degradation of endosulfan pesticide by gold nanoparticles
Get PDFSpherical shaped gold nanoparticles (GNPs) of size around similar to 9 nm were successfully used for photocatalytic degradation of hazardous endosulfan (ES) pesticide. GNPs absorb sunlight at ambient condition in aqueous medium to enhance localized surface plasmon resonance (LSPR) which initiate hydrolysis, oxidation and reduction chemical reactions for the mineralization of ES molecules. Infrared transmittance spectra of GNPs treated ES solutions revealed formation of amorphous carbon and hydrocarbon as final reaction products indicating the nearly complete mineralization of ES as evidenced from their TEM images also. The disappearance of chloro carbon and sulphite functional groups peaks of ES in IR transmittance spectra confirmed their degradation. TEM images also support the optical absorption spectra consisting of inter-band and LSPR bands pertaining to individual and clustered GNPs ensembles. The redshift in LSPR absorption peak positions along minor and major axis of clustered GNPs ensembles is attributed to the change in GNPs polarizability on interaction with the electric component of visible light. The chemical reaction pathway for ES molecule degradation by the photocatalytic GNPs has been proposed in the light of inferences drawn from TEM images, IR transmittance and optical absorption spectra