Determination of IgG1 and IgG3 SARS-CoV-2 Spike Protein and Nucleocapsid Binding—Who Is Binding Who and Why?

The involvement of immunoglobulin (Ig) G3 in the humoral immune response to SARS-CoV-2 infection has been implicated in the pathogenesis of acute respiratory distress syndrome (ARDS) in COVID-19. The exact molecular mechanism is unknown, but it is thought to involve this IgG subtype’s differential ability to fix, complement and stimulate cytokine release. We examined the binding of convalescent patient antibodies to immobilized nucleocapsids and spike proteins by matrix-assisted laser desorption/ionization–time of flight (MALDI-ToF) mass spectrometry. IgG3 was a major immunoglobulin found in all samples. Differential analysis of the spectral signatures found for the nucleocapsid versus the spike protein demonstrated that the predominant humoral immune response to the nucleocapsid was IgG3, whilst for the spike protein it was IgG1. However, the spike protein displayed a strong affinity for IgG3 itself, as it would bind from control plasma samples, as well as from those previously infected with SARS-CoV-2, similar to the way protein G binds IgG1. Furthermore, detailed spectral analysis indicated that a mass shift consistent with hyper-glycosylation or glycation was a characteristic of the IgG3 captured by the spike protein.     

The interplay of conscious and automatic mechanisms in the context of routine use: An integrative and comparative study of contrasting mechanisms

Researchers have been closely studying how information technology services became a routine part of our lives. Studies have found that users who routinely use online services either consciously develop loyalty or automatically develop a habit. But many studies now mix the elements of conscious and automatic use despite the great differences in these phenomena. This study proposes a new theoretical framework of how the conscious and automatic mechanisms simultaneously, but differentially, regulate postadoption phenomena in the context of online information services. An empirical test confirms that these two mechanisms have highly discernible patterns that researchers and managers alike must heed.     

A Critical Grain Size Concept to Predict the Impact Transition Temperature of Ti-Microalloyed Steels

Based on the assumption that local principal stress remains the same everywhere within a ferrite grain, a critical value of grain size can be determined for a fixed TiN particle size. When the grain size is smaller than the critical size, grain boundary is expected to resist the propagation of a micro-crack that is initiated from a TiN particle. Using this concept, an attempt has been made to predict the local cleavage fracture stress and 27J impact transition temperature (ITT) of different Ti-microalloyed steels, which were subjected to (instrumented) Charpy impact testing.     

A novel DSP‐based PFC‐DPLL with fuzzy controlled acquisition aid to improve acquisition performance and noise immunity

This paper proposes a new digital signal processing (DSP)‐based phase frequency controlled digital phase locked loop. Here, a very simplistic form of fuzzy logic controller with the help of carrier phase and frequency error as input data is used to provide an acquisition aid. A frequency discriminator is employed to generate frequency error, and phase detector output is taken for phase error. This addition of an acquisition aid helps the loop to achieve the minimum acquisition time and maximum noise rejection simultaneously. An additional phase control in the digitally controlled oscillator makes the loop perform even better towards this goal. The implementation of the proposed loop is carried out on a reconfigurable logic platform using System Generator^®;, a tool from Xilinx^®; used to design real‐time DSP application. A significant improvement of time domain characteristics are observed as well as the performance in presence of additive white Gaussian noise is demonstrated in terms of the reduction in steady‐state phase jitter and enhancement in output signal to noise ratio in the proposed loop. Copyright © 2014 John Wiley & Sons, Ltd.     

Self‐Healing Reduced Graphene Oxide Films by Supersonic Kinetic Spraying

The industrial scale application of graphene and other functional materials in the field of electronics has been limited by inherent defects, and the lack of simple deposition methods. A simple spray deposition method is developed that uses a supersonic air jet for a commercially available reduced graphene oxide (r‐GO) suspension. The r‐GO flakes are used as received, which are pre‐annealed and pre‐hydrazine‐treated, and do not undergo any post‐treatment. A part of the considerable kinetic energy of the r‐GO flakes entrained by the supersonic jet is used in stretching the flakes upon impact with the substrate. The resulting “frozen elastic strains” heal the defects (topological defects, namely Stone‐Wales defect and C₂ vacancies) in the r‐GO flakes, which is reflected in the reduced ratio of the intensities of the D and G bands in the deposited film. The defects can also be regenerated by annealing.     

High Performance CMOS Analog Arithmetic Circuits

Unique designs for CMOS analog arithmetic circuits are presented which perform addition (V₁ + V₂), subtraction (V₂ – V₁), add/invert –(V₁ + V₂), and multiply (V₁ × V₂). The circuit operation is based on the inherent square law of MOS transistor drain current when operating in the saturation region. Key features include: good linearity and accuracy, single ended voltage inputs and output, wide input and output range and no input bias voltages. The circuits can be directly coupled (no buffer) and serve as basic building blocks for analog signal processing implementations such as analog filters and adaptive equalizers. All circuits were implemented in 1.2 m CMOS technology.     

Compact Harmonic Filter Design and Fabrication Using IPD Technology

An integrated passive device (IPD) technology has been developed to meet the ever increasing needs of size and cost reduction in radio front-end transceiver module applications. Electromagnetic (EM) simulation was used extensively in the design of the process technology and the optimization of inductor and harmonic filter designs and layouts. Parameters such as inductor shape, inner diameter, metal thickness, metal width, and substrate thickness have been optimized to provide inductors with high quality factors. The technology includes 1) a thick plated gold metal process to reduce resistive loss; 2) MIM capacitors using PECVD SiN dielectric layer; 3) airbridges for inductor underpass and capacitor pick-up; and 4) a 10 mil finished GaAs substrate to improve inductor quality factor. Both lumped element circuit simulations and electromagnetic (EM) simulations have been used in the harmonic filter circuit designs for high accuracy and fast design cycle time. This paper will present the EM simulation calibration and demonstrate the importance of using EM simulation in the filter design in order to achieve first-time success in wafer fabrication. The fabricated IPD devices have insertion loss of 0.5 dB and harmonic rejections of 30dB with die size of 1.42 mm for high band (1710 MHz-1910 MHz) and 1.89 mm for low band (824-915 MHz) harmonic filters.     

Mechanical Properties of Robust Ultrathin Silk Fibroin Films

Robust ultrathin multilayer films of silk fibroin were fabricated by spin coating and spin‐assisted layer‐by‐layer assembly and their mechanical properties were studied both in tensile and compression modes for the first time. The ultrathin films were characterized by a high elastic modulus of 6–8 GPa (after treatment with methanol) with the ultimate tensile strength reaching 100 MPa. The superior toughness is also many times higher than that usually observed for conventional polymer composites (328 kJ m^–3 for the silk material studied here versus typical values of < 100 kJ m^–3). These outstanding properties are suggested to be caused by the gradual development of the self‐reinforcing microstructure of highly crystalline β‐sheets, serving as reinforcing fillers and physical crosslinks, a process that is well known for bulk silk materials but it is demonstrated here to occur in ultrathin films as well, despite their limited dimensions. However, the confined state within films thinner than the lengths of the extended domains causes a significantly reduced elasticity which should be considered in the design of nanosized films from silk materials. Such regenerated silk fibroin films with outstanding mechanical strength have potential applications in microscale biodevices, biocompatible implants, and synthetic coatings for artificial skin.     

遥控器漫谈

现今遥控器以各种形式或载体走进了千家万户,每个家庭都拥有若干类型的家电,相应遥控器就有一大堆,经常在使用中便会出现遥控故障。本刊2007年第一