The Experts below are selected from a list of 138291 Experts worldwide ranked by ideXlab platform
J E Butler - One of the best experts on this subject based on the ideXlab platform.
-
solid supports in enzyme linked immunosorbent assay and other solid phase immunoassays
Methods in molecular medicine, 2004Co-Authors: J E ButlerAbstract:Most modern immunoassays involve the use of synthetic solid phases to immobilize one of the reactants, often by simple adsorption. These solid-phase immunoassays (SPIs) involve ligand-receptor interactions that occur within a reaction volume close to the solution/solid-phase interface. As a consequence, the immunochemistry/biochemistry of these ligand-receptor interactions differ from their counterparts in solution. Nevertheless, Mass Law equations can be derived for measuring the antigen capture of solid-phase antibodies, for determining the affinity of solid phases for protein adsorption, and for estimating antibody affinity. Many proteins adsorbed on polystyrene or silicone suffer adsorption-induced conformational changes (ACC) and are partially or largely denatured. Alternative methods for immobilizing proteins and virus, while preserving antigenicity, may yield only a modest increase in functional reactant concentration. Peptides and small recombinant proteins appear to benefit especially from nonadsorptive immobilization. Not all solid phases commonly used in SPIs have the same properties, the same capacity for reactant immobilization, cause the same level of denaturation, or experience the same level of nonspecific binding. Empiricism, adherence to a few practical rules of thumb, and avoidance of certain "old wives tales" can be valuable in the successful development of SPIs.
-
solid supports in enzyme linked immunosorbent assay and other solid phase immunoassays
Methods, 2000Co-Authors: J E ButlerAbstract:A very large proportion of modern immunoassays involve the use of synthetic solid phases to immobilize one of the reactants. These solid-phase immunoassays (SPIs) therefore involve ligand-receptor interactions that occur within a reaction volume close to the solution/solid phase interface. As a consequence, the immunochemistry/biochemistry of these ligand-receptor interactions differs from that of their counterparts in solution. Furthermore, the immobilization process can significantly alter the biological activity of the reactant; most adsorbed proteins on polystyrene or silicone are partially or largely denatured. Therefore the use of alternative methods of immobilization is attractive but may result in little increase in the amount of total functional reactant. However, all commonly used solid phases do not have the same properties or the same capacity for reactant immobilization or experience the same level of nonspecific binding. Empiricism plays a major role in SPIs. Derivations of Mass Law equations for measuring the antigen capture of solid-phase antibodies, for determining the affinity of solid phase for protein adsorption, and for estimating antibody affinity are reviewed.
Xisen Wen - One of the best experts on this subject based on the ideXlab platform.
-
ultra thin smart acoustic metasurface for low frequency sound insulation
Applied Physics Letters, 2016Co-Authors: Hao Zhang, Yong Xiao, Jihong Wen, Xisen WenAbstract:Insulating low-frequency sound is a conventional challenge due to the high areal Mass required by Mass Law. In this letter, we propose a smart acoustic metasurface consisting of an ultra-thin aluminum foil bonded with piezoelectric resonators. Numerical and experimental results show that the metasurface can break the conventional Mass Law of sound insulation by 30 dB in the low frequency regime (<1000 Hz), with an ultra-light areal Mass density (<1.6 kg/m2) and an ultra-thin thickness (1000 times smaller than the operating wavelength). The underlying physical mechanism of such extraordinary sound insulation performance is attributed to the infinite effective dynamic Mass density produced by the smart resonators. It is also demonstrated that the excellent sound insulation property can be conveniently tuned by simply adjusting the external circuits instead of modifying the structure of the metasurface.
-
sound transmission loss of metamaterial thin plates with periodic subwavelength arrays of shunted piezoelectric patches
Journal of Sound and Vibration, 2015Co-Authors: Hao Zhang, Yong Xiao, Jihong Wen, Gang Wang, Xisen WenAbstract:Abstract This paper studies sound transmission loss (STL) of a metamaterial thin plate consisting of periodic subwavelength arrays of shunted piezoelectric patches bonded to the two surfaces of an unbounded homogeneous thin plate. An effective medium method is developed to calculate STL of such metamaterial thin plates. The effective medium method is validated by comparing with the results calculated from the finite element method. Numerical results show that the metamaterial plate with shunted piezoelectric patches (all of the shunting circuits are closed) can achieve much higher STL than the unshunted case (all of the shunting circuits are opened) within the Mass-Law region and coincidence region of sound transmission. The unique STL of the metamaterial plate can be well understood by explicit formulations derived based on the effective medium method. It is also shown that the bandwidth of increased STL of the metamaterial plate can be significantly broadened by utilizing negative capacitance shunting circuits.
-
Sound transmission loss of metamaterial-based thin plates with multiple subwavelength arrays of attached resonators
Journal of Sound and Vibration, 2012Co-Authors: Yong Xiao, Jihong Wen, Xisen WenAbstract:Abstract This paper is concerned with sound transmission loss of metamaterial-based thin plates consisting of multiple subwavelength arrays of spring–Mass resonators attached to an unbounded homogenous thin plate. Two analytical wave approaches are developed for the calculation of diffuse field sound transmission loss of such metamaterial-based thin plates. Numerical results show that a metamaterial-based plate can result in much higher sound transmission loss than a bare plate (with the same surface Mass density) at frequencies within the Mass-Law region and the coincidence region. It is also demonstrated that by using an extremely thin plate to form a metanaterial-based plate, the construction can be implemented as a potential sound insulation material with good performance at low frequencies.
Steven Nutt - One of the best experts on this subject based on the ideXlab platform.
-
membrane type metamaterials transmission loss of multi celled arrays
Journal of Applied Physics, 2011Co-Authors: Christina J Naify, Chiaming Chang, Geoffrey P Mcknight, Florian Scheulen, Steven NuttAbstract:Acoustic metamaterials with negative dynamic Mass density have been shown to demonstrate a five-fold increase in transmission loss (TL) over Mass Law predictions for a narrowband (100 Hz) at low frequencies (100–1000 Hz). The present work focuses on the scale-up of this effect by examining the behavior of multiple elements arranged in arrays. Single membranes were stretched over rigid frame supports and Masses were attached to the center of each divided cell. The TL behavior was measured for multiple configurations with different magnitudes of Mass distributed across each of the cell membranes in the array resulting in a multipeak TL profile. To better understand scale-up issues, the effect of the frame structure compliance was evaluated, and more compliant frames resulted in a reduction in the TL peak frequency bandwidth. In addition, displacement measurements of frames and membranes were performed using a laser vibrometer. Finally, the measured TL of the multi-celled structure was compared with the TL behavior predicted by finite element analysis to understand the role of nonuniform Mass distribution and frame compliance.
-
transmission loss and dynamic response of membrane type locally resonant acoustic metamaterials
Journal of Applied Physics, 2010Co-Authors: Christina J Naify, Chiaming Chang, Geoffrey P Mcknight, Steven NuttAbstract:Membrane-type acoustic metamaterials were fabricated, characterized, and analyzed to understand their acoustic response. Thin plates which obey the acoustic Mass Law have low transmission loss (TL) at low frequencies. Acoustic metamaterials with negative dynamic Mass density have been shown to demonstrate a significant (5×) increase in TL over Mass Law predictions for a narrow band (100 Hz) at low frequencies (100–1000 Hz). The peak TL frequency can be tuned to specific values by varying the membrane and Mass properties. In this work, TL magnitude as a function of frequency was measured for variations in the Mass magnitude and membrane tension using an impedance tube setup. The dynamic properties of membranes constructed from different materials were measured and compared to the results of coupled field acoustic-structural finite element analysis modeling to understand the role of tension and element quality factor. To better comprehend the mechanism(s) responsible for the TL peak, a laser vibrometer was used to map the out-of-plane dynamic response of the structure under acoustic loading at discrete frequencies. Negative dynamic Mass was experimentally demonstrated at the peak TL frequency.
-
sound transmission loss of honeycomb sandwich panels
Noise Control Engineering Journal, 2006Co-Authors: Shankar Rajaram, Tongan Wang, Steven NuttAbstract:Honeycomb sandwich panels used for commercial applications are typically stiff and lightweight. They are optimized for mechanical performance, but have poor acoustical performance. Transmission loss (TL) is one of the metrics used to assess the acoustical performance of honeycomb sandwich panels. Transmission loss for these panels shows inferior Mass Law performance above coincidence frequency for commercially available panels. For superior transmission loss performance, it is critical to delay (maximize) the coincidence frequency, which is determined by the dispersive panel bending waves. Panel bending waves are characterized by three frequency regimes - total panel bending, core shear, and individual skin bending. These regimes are controlled by panel geometry, panel Mass and elastic properties of the core and the skins. The coincidence frequency can be increased by designing panels with core shear wave speeds that are subsonic. In the present study, the influence of different panel design parameters, such as core density, core material, cell size, and cell structure, on the transmission loss of honeycomb sandwich panels is analyzed. Moreover, TL results of panels in three classes of core shear wave speeds - subsonic, transonic, and supersonic - are presented. For panels with supersonic shear wave speed, core density influences TL above the coincidence frequency, but other parameters like cell size and skin type show negligible effects. Panels with subsonic and transonic core shear wave speeds show improved acoustic performance compared to their supersonic counterparts. The mechanical performance of subsonic and transonic panel designs is generally inferior but can be improved when accompanied by weight increase.
Yoon Tae Hwang - One of the best experts on this subject based on the ideXlab platform.
-
development of a practical two microphone impedance tube method for sound transmission loss measurement of sound isolation materials
International Journal of Air-conditioning and Refrigeration, 2003Co-Authors: Singnam Ro, Yoon Tae HwangAbstract:This study developed a practical two-microphone impedance tube method to measure the sound transmission loss of sound isolation materials without the use of an expensive reverberation room or an acoustic intensity probe. In order to evaluate the validation and applicability of the two-microphone impedance tube method, sound transmission losses for several sound isolation materials with different surface density and bending stiffness were measured, and the measured values were compared with the results from the reverberation room method and the theory. From the experimental results, it was found that the accuracy of sound transmission loss obtained by the impedance tube method depends upon the diameter size of the impedance tube (i.e., tested sample size). For sound isolation materials having relatively large bending stiffness such as acryl, wood, and aluminum plates, it was found that the impedance tube method proposed by this study was not valid to measure the sound trans loss. On the other hand, for sound isolation materials having relatively small bending stiffness such as rubber, polyvinyl, and asphalt sheets, the comparisons of transmission loss between the results from the impedance tube method and the theory showed a good agreement within the range of the frequencies satisfying the normal incidence Mass Law. Therefore, the two-microphone impedance tube method proposed by this study can be an effective measurement method to evaluate the sound transmission loss for soft sound isolation sheets having relatively small bending stiffness.
Yong Xiao - One of the best experts on this subject based on the ideXlab platform.
-
ultra thin smart acoustic metasurface for low frequency sound insulation
Applied Physics Letters, 2016Co-Authors: Hao Zhang, Yong Xiao, Jihong Wen, Xisen WenAbstract:Insulating low-frequency sound is a conventional challenge due to the high areal Mass required by Mass Law. In this letter, we propose a smart acoustic metasurface consisting of an ultra-thin aluminum foil bonded with piezoelectric resonators. Numerical and experimental results show that the metasurface can break the conventional Mass Law of sound insulation by 30 dB in the low frequency regime (<1000 Hz), with an ultra-light areal Mass density (<1.6 kg/m2) and an ultra-thin thickness (1000 times smaller than the operating wavelength). The underlying physical mechanism of such extraordinary sound insulation performance is attributed to the infinite effective dynamic Mass density produced by the smart resonators. It is also demonstrated that the excellent sound insulation property can be conveniently tuned by simply adjusting the external circuits instead of modifying the structure of the metasurface.
-
sound transmission loss of metamaterial thin plates with periodic subwavelength arrays of shunted piezoelectric patches
Journal of Sound and Vibration, 2015Co-Authors: Hao Zhang, Yong Xiao, Jihong Wen, Gang Wang, Xisen WenAbstract:Abstract This paper studies sound transmission loss (STL) of a metamaterial thin plate consisting of periodic subwavelength arrays of shunted piezoelectric patches bonded to the two surfaces of an unbounded homogeneous thin plate. An effective medium method is developed to calculate STL of such metamaterial thin plates. The effective medium method is validated by comparing with the results calculated from the finite element method. Numerical results show that the metamaterial plate with shunted piezoelectric patches (all of the shunting circuits are closed) can achieve much higher STL than the unshunted case (all of the shunting circuits are opened) within the Mass-Law region and coincidence region of sound transmission. The unique STL of the metamaterial plate can be well understood by explicit formulations derived based on the effective medium method. It is also shown that the bandwidth of increased STL of the metamaterial plate can be significantly broadened by utilizing negative capacitance shunting circuits.
-
Sound transmission loss of metamaterial-based thin plates with multiple subwavelength arrays of attached resonators
Journal of Sound and Vibration, 2012Co-Authors: Yong Xiao, Jihong Wen, Xisen WenAbstract:Abstract This paper is concerned with sound transmission loss of metamaterial-based thin plates consisting of multiple subwavelength arrays of spring–Mass resonators attached to an unbounded homogenous thin plate. Two analytical wave approaches are developed for the calculation of diffuse field sound transmission loss of such metamaterial-based thin plates. Numerical results show that a metamaterial-based plate can result in much higher sound transmission loss than a bare plate (with the same surface Mass density) at frequencies within the Mass-Law region and the coincidence region. It is also demonstrated that by using an extremely thin plate to form a metanaterial-based plate, the construction can be implemented as a potential sound insulation material with good performance at low frequencies.