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Ultra-Sensitive Detection of Proteins Using Chemically Modified Nanoporous PVDF Membrane with Attenuated Near IR Autofluorescence
No full textWe report the lowest autofluorescent nanoporous polyvinylidene fluoride (PVDF) membranes exhibit near infra-red (NIR) emission properties for western blot detection of high and low molecular weight proteins. The design involves post modification of PVDF membranes by an alkali treatment that reduces the native of PVDF at 450-520nm. The background fluorescence of these modified membranes is eight times lower than the commercial available PVDF membranes and displayed NIR emission at 750nm. Imparted alkene conjugated double bonds in the polymeric backbone by alkali treatment causes the NIR emission in the modified PVDF membranes and this translates improvement in detection of, in particular, high molecular weight proteins (130 kDa) compared to traditional western blot. To validate the pore size effect, two different pores sized (similar to 100nm and similar to 0.8m) PVDF membranes were prepared, surface modified and subjected for protein profiling. High linearity was achieved in detection of high molecular weight proteins and significant protein binding was noticed for the alkali treated membranes of similar to similar to 100nm size. The methodology permits the design of modified PVDF membranes with lesser pore size could be an alternative for existing membranes with minimal autofluorescence for efficient and quick detection of high molecular weight proteins
A Game Theoretic Distributed Algorithm for FeICIC Optimization in LTE-A HetNets (vol 25, pg 3500, 2017)
No full textLow-voltage high-reliability MEMS switch for millimeter wave 5G applications
No full textLack of reliability of radio-frequency microelectromechanical systems (RF MEMS) switches has inhibited their commercial success. Dielectric stiction/breakdown and mechanical shock due to high actuation voltage are common impediments in capacitive MEMS switches. In this work, we report low-actuation voltage RF MEMS switch and its reliability test. Experimental characterization of fabricated devices demonstrate that proposed MEMS switch topology needs very low voltage (4.8 V) for actuation. The mechanical resonant frequency, f(0), quality factor, Q, and switching time are measured to be 8.35 kHz, 1.2, and 33 microsecond, respectively. These MEMS switches have high reliability in terms of switching cycles. Measurements are performed using pulse waveform of magnitude of 6 V under hot-switching condition. Temperature measurement results confirm that the reported switch topology has good thermal stability. The robustness in terms of the measured pull-in voltage shows a variation of 0.08 V degrees C-1. Lifetime measurement results after 10 million switching cycles demonstrate insignificant change in the RF performance without any failure. Experimental results show that low voltage improves the lifetime. Low insertion loss (less than 0.6 dB) and improved isolation (above 40 dB) in the frequency range up to 60 GHz have been reported. Measured RF characteristics in the frequency range from 10 MHz to 60 GHz support that these MEMS switches are favorable choice for mm-wave 5G applications
Chiro-plasmonic refractory metamaterial with titanium nitride (TiN) core-shell nanohelices
No full textChiral metamaterials are obtained by assembling plasmonic elements in geometries with broken mirror symmetry, which can have promising applications pertaining to generation, manipulation and detection of optical polarisation. The materials used to fabricate this promising nanosystem, especially in the visible-NIR regime, are limited to noble metals such as Au and Ag. However, they are not stable at elevated temperatures and in addition, incompatible with CMOS technologies. We demonstrate that it is possible to develop a chiro-plasmonic system based on a refractory material such as titanium nitride (TiN) which does not have these disadvantages. The building block of our metamaterial is a novel core-shell helix, obtained by coating TiN over silica nanohelices. These were arranged in a regular two-dimensional array over cm-scale areas, made possible by the use of scalable fabrication techniques such as laser interference lithography, glancing angle deposition and DC magnetron sputtering. The measured chiro-optical response was extremely broadband (<500 nm to >1400 nm), and had contributions from individual, as well as collective plasmon modes of the interacting nanohelices, whose spectral characteristics could be easily controlled by varying the direction of the incident radiation
Demonstration of high-responsivity epitaxial beta-Ga2O3/GaN metal-heterojunction-metal broadband UV-A/UV-C detector
No full textWe demonstrate epitaxial beta-Ga2O3/GaN-based vertical metal-heterojunction-metal (MHM) broadband UV-A/UV-C photodetectors with high responsivity (3.7A/W) at 256 and 365 nm, UV-to-visible rejection > 10(3), and a photo-to-dark current ratio of similar to 100. A small (large) conduction (valence) band offset at the heterojunction of pulsed laser deposition (PLD)-grown beta-Ga2O3 on metal organic chemical vapor deposition (MOCVD)-grown GaN-on-silicon with epitaxial registry, as confirmed by X-ray diffraction (XRD) azimuthal scanning, is exploited to realize detectors with an asymmetric photoresponse and is explained with one-dimensional (1D) band diagram simulations. The demonstrated novel vertical MHM detectors on silicon are fully scalable and promising for enabling focal plane arrays for broadband ultraviolet sensing. (C) 2018 The Japan Society of Applied Physic
Study on the Conformation of Entrapped Protein inside the Reverse Micellar Confinement Based on the Amino Acid Derived Ionic Liquid
No full textOwing to superior surface-activity and versatility in functionalization compared to conventional surfactants, surface-active ionic liquids (SAILs) gained immense interest in recent years. Toxicity and biodegradation remain central issues while dealing with the SAILs and thus, the quest for synthesis of greener SAILs is increasing day by day. Keeping in view of the importance of SAIL's performance, we undertook the present study for the formulation of reverse micelles (RMs) using biodegradable L-proline propyl ester lauryl sulfate (ProC(3)]LS]) in cyclohexane (Cy). The formation of RMs was confirmed from the phase behavior and dynamic light scattering (DLS) studies. Fourier-transform infrared spectroscopy (FTIR) study revealed the solvation of anionic head group through H-bonding by added water. An increased micropolarity and reduced microviscosity were evidenced inside the RM droplets as a function of hydration level. Finally, the encapsulation of BSA protein in RMs was investigated through the fluorescence, circular dichroism and DLS studies, which showed conformation with higher degree of secondary structural content than the native state inside the droplet core at higher hydration. Our results signify the importance of the role of hydration in the function of enzyme or protein molecules in molecular crowding environments. These facts certainly prove the versatility of this kind of organized assemblies to alter their inherent properties simply by changing water content
A strong and deformable in-situ magnesium nanocomposite igniting above 1000 degrees C
No full textMagnesium has been trending of late in automobile, aerospace, defense, sports, electronic and biomedical sectors as it offers an advantage in light-weighting. In aluminum, titanium, and steel dominated aerospace and defense sectors, applications of Mg were banned/restricted until recently due to perceived easy ignition and inability to self-extinguish immediately. Strength is generally inversely related to ductility, weak texture and unrelated to ignition resistance, making it challenging to optimize all four concurrently in a material. We address this challenge by designing a low density (similar to 1.76 g.cm(-3)) in-situ Mg nanocomposite. It is a resultant of a sequence of in-situ reactions during melt processing and extrusion. The in-situ formed Y2O3 nanoparticles exhibit coherency with matrix and lead to development of large amount of elastic and plastic strain fields around them. These nanoparticles and secondary phases (Mg2Ca and Mg2Y) are responsible for the nanocomposite's high tensile strength (similar to 343 MPa). A weak texture mediated tensile ductility of 30% and compressive failure strain of 44% is observed. Further, the ignition temperature increased to 1045 degrees C (near the boiling point of Mg) due to the formation of protective surficial oxide layers aided by the presence of insulating Y2O3 nanoparticles, rendering the nanocomposite outperform other traditional commercial Mg-based materials
Metallic conductivity beyond the Mott minimum in PEDOT: Sulphate at low temperatures
No full textElastic scattering mechanisms dominate the charge transport in crystalline metals, resulting in a characteristic increase in conductivity at low temperatures. However, disorder - arising, for example, from alloying - can hamper transport and lead to decreased coherence among scattered electrons (ie. inelastic scattering). This is typically the situation in non-crystalline metals. Likewise, conductive polymers are particularly prone to defect states with decreased carrier mobility (i.e. electrical conductivity). We present the first report of conduction in the elastic scattering regime in conductive polymers without the detrimental effect on conductivity. As in a crystalline metal, conductivity increases upon cooling. More specifically, we observed a minimum conductivity in free-standing metallic PEDOT:sulphate at around 4 K. The polymer chains, which form crystallites of around 800 angstrom in size, exhibit an extraordinary degree of spatial and energetic order. We show that increasing pressure enabled us to shift the minimum upwards, thus achieving metallic conductivity at up to 10 K with a calculated mean-free path of around 250 angstrom. These results underline the existence of true metallic states in conductive polymers at low temperatures
Blue- and Red-Shifting Hydrogen Bonding: A Gas Phase FTIR and Ab Initio Study of RR ` CO center dot center dot center dot DCCI3 and RR ` S center dot center dot center dot DCCI3 Complexes
No full textBlue-shifting H-bonded (C-D...O) complexes between CDCI3 and CH3HCO, (CH3)(2)CO3 and C2H5(CH3)CO, and red-shifting H-bonded (C-D...S) complexes between CDCI3 with (CH3)(2)S and (C2H5)(2)S have been identified by Fourier transform infrared spectroscopy in the gas phase at room temperature. With increasing partial pressure of the components, a new band appears in the C-D stretching region of the vibrational spectra. The intensity of this band decreases with an increase in temperature at constant pressure, which provides the basis for identification of the H-bonded bands in the spectrum. The C-D stretching frequency of CDCI3 is blue-shifted by +7.1, +4, and +3.2 cm(-1) upon complexation with CH3HCO, (CH3)(2)CO3 and C2H5(CH3)CO, respectively, and red-shifted by -14 and -19.2 cm(-1) upon complexation with (CH3)(2)S and (C2H5)(2)S, respectively. By using quantum chemical calculations at the MP2/6-311++G** level, we predict the geometry, electronic structural parameters, binding energy, and spectral shift of H bonded complexes between CDCI3 and two series of compounds named RCOR' (H2CO, CH3HCO, (CH3)(2)CO3 and C2H5(CH3)CO) and RSR' (H2S, CH3HS, (CH3)(2)S, and (C2H5)(2)S) series. The calculated and observed spectral shifts follow the same trends. With an increase in basicity of the H-bond acceptor, the C-D bond length increases, force constant decreases, and the frequency shifts to the red from the blue. The potential energy scans of the above complexes are done, which show that electrostatic attraction between electropositive D and electron-rich O/S causes bond elongation and red shift, and the electronic and nuclear repulsions lead to bond contraction and blue shifts. The dominance of the two opposing forces at the equilibrium geometry of the complex determines the nature of the shift, which changes both in magnitude and in direction with the basicity of the hydrogen-bond acceptor
Raman based power combining and wavelength conversion of high power ytterbium fiber lasers
No full textIn this work, we demonstrate an architecture to perform Raman-based power combining and simultaneous wavelength conversion of two independently controlled high-power Ytterbium doped fiber lasers operating at different wavelengths into a single laser line at the 1.5-micron band. Specifically, we have been able to achieve an in-band output power of similar to 99W with a conversion of similar to 64% of the quantum limited efficiency. This power combining is illustrated for different cases of the input wavelengths of the Ytterbium fiber laser. In each case, we have been able to demonstrate a power combining of >87 W in the final 1.5-micron band, with more than 85% of the fraction of the power residing in the final desired band