Study of Forward and Backward Modes in Double-Sided Dielectric-Filled Corrugated Waveguides

This work studies the propagation characteristics of a rectangular waveguide with aligned/ misaligned double-sided dielectric-filled metallic corrugations. Two modes are found to propagate in the proposed double-sided configuration below the hollow-waveguide cutoff frequency: a quasi-resonant mode and a backward mode. This is in contrast to the single-sided configuration, which only allows for backward propagation. Moreover, the double-sided configuration can be of interest for waveguide miniaturization on account of the broader band of its backward mode. The width of the stopband between the quasi-resonant and backward modes can be controlled by the misalignment of the top and bottom corrugations, being null for the glide-symmetric case. The previous study is complemented with numerical results showing the impact of the height of the corrugations, as well as the filling dielectric permittivity, on the bandwidth and location of the appearing negative-effective-permeability band. The multi-modal transmission-matrix method has also been employed to estimate the rejection level and material losses in the structure and to determine which port modes are associated with the quasi-resonant and backward modes. Finally, it is shown that glide symmetry can advantageously be used to reduce the dispersion and broadens the operating band of the modes.

Multiplex immunofluorescence of spatial distribution of infiltrating T cells in different regions of hepatic lobules during liver transplantation rejection

It is still unclear whether there are differences in the types and functional status of immune cells in different areas of the liver lobules after liver transplantation rejection. The composition of infiltrating T cells in liver allografts during liver transplantation rejection is unclear and difficult to visualize on the same biopsy slide. We used multiplex immunofluorescence assays to study the spatial distribution of various types of infiltrating T cells in different areas of the liver lobules after liver transplantation. In the same area of the hepatic lobules, the percentage of CD4 + T cells, CD8 + T cells and regulatory T cells (Tregs) in the acute rejection group was higher than that in the nonacute rejection and normal groups. Within all three groups, the percentage of CD4 + T cells, CD8 + T cells and Tregs from the periportal to perivenous zones was increased first and then decreased. The percentage of CD8 + T cells increased gradually from the periportal to perivenous zones, the percentage of CD8 + T cells in perivenous zone was higher than in the transitional and periportal zones in the rejection group. In conclusion, the percentage of CD8 + T cells in different regions of liver lobules is closely related to rejection level after liver transplantation. Acute liver transplantation rejection may occur when the percentage of CD8 + T cells in the perivenous zone increases. Although the percentage of regional CD4 + T could not reflect the rejection level, but the number of CD4 + and CD8 + T cells in different regions was closely related to the rejection level.

Band-Pass Filtering Cross-Polarization Converter Using Transmitarrays

Microwave devices with polarization conversion and band-pass filtering response have great application prospects on radomes. Here, the concepts of band-pass filters and cross-polarization converters are combined to realize a band-pass filtering cross-polarization converter with an extremely high polarization-conversion ratio. Most importantly, the device has an excellent out-of-band rejection level, above 30 and 40 dB for the lower and upper edges, respectively. In addition, the transmission zeros of the passband can be flexibly tuned independently. The band-pass filtering polarization converter was simulated, fabricated, and measured, and the measured results were found to be in good agreement with the simulation results.

Cornering (quasi) degenerate neutrinos with cosmology

In light of the improved sensitivities of cosmological observations, we examine the status of quasi-degenerate neutrino mass scenarios. Within the simplest extension of the standard cosmological model with massive neutrinos, we find that quasi-degenerate neutrinos are severely constrained by present cosmological data and neutrino oscillation experiments. We find that Planck 2018 observations of cosmic microwave background (CMB) anisotropies disfavour quasi-degenerate neutrino masses at 2.4 Gaussian σ’s, while adding baryon acoustic oscillations (BAO) data brings the rejection to 5.9σ’s. The highest statistical significance with which one would be able to rule out quasi-degeneracy would arise if the sum of neutrino masses is ∑mv = 60 meV (the minimum allowed by neutrino oscillation experiments); indeed a sensitivity of 15 meV, as expected from a combination of future cosmological probes, would further improve the rejection level up to 17σ. We discuss the robustness of these projections with respect to assumptions on the underlying cosmological model, and also compare them with bounds from β decay endpoint and neutrinoless double beta decay studies.

Exploring New and Modified Rejection-Type Thresholds Using Cricket Snack Crackers

Recently, sensory threshold concepts have been expanded to include affective perceptions of foods and beverages, especially measures of product rejection; however, each threshold interpretation depends largely on the methodology employed. By substituting cricket powder for whole-wheat flour in snack crackers (0%, 5%, 10%, 15%, and 20%), we proposed modifications to two existing threshold methodologies: a modified consumer rejection threshold (M-CRT) using a 2-alternative choice (2-AC) preference test with “no preference” option; and a modified hedonic rejection threshold (M-HRT) based on less-than-neutral hedonic scores according to a one-sample t-test. We also proposed two new concepts: a rejection tolerance threshold (RTT) and an associated rejection range (RR), based on a binomial acceptability question and a probit regression model. These new methods provide more realistic interpretations of rejection-type thresholds based on user-defined allowable rejection levels, or “rejection tolerance” (for RTT), and a model-derived stimulus range (RR) to capture the rejection level of interest while providing flexibility for product formulation. All thresholds were investigated separately for color, flavor, texture and overall perception, elucidating differential sensorial effects of our novel ingredient on the food matrix. We suggest that conducting all demonstrated techniques in a single testing session gives a more expansive view of rejection thresholds while requiring minimal additional resources.

Quality Circle: A Methodology to Enhance the Plant Capacity through Why-Why Analysis

In the manufacturing firms, hospitals, banks, schools and research institutes etc., total customer satisfaction with products and services have very much importance and also necessary for their survival. Quality services and reducing wastages of all types are the primary need of every organisation. Quality Circle is (QC) is one of the techniques that can be utilised to solve industrial problems and can reduce the rejection level. In present paper, QC concept is implemented to solve wastage problem by taking a real case study of an automobile industry. The observed data was analysed through various problem solving techniques such as 80/20 rule and fishbone diagram etc. Finally, Why-Why analysis was carried out to identify the root cause of the problem and suggested actions to solve the problem. The following results were obtained: Gradually reduction in materials wastage minimises the rejection and hence reduces the overhead expenses of the firm. Further, QC helps in motivating employees to do their best for the organisation, which not only improves the productivity of the organisation, but also helps in discovering hidden talent and creative skill of the workforce. Finally, QC helps in developing the sense of belongingness towards organisations.

Compact wide stopband microstrip lowpass filter using polygon patches and meandered lines

In this paper, a low pass filter based on T-Shaped resonator is presented. The T-Shaped resonator consists of meandered lines and rectangular patches. Also, the LC model and transfer function of the proposed resonator is presented. For suppression of spurious harmonics, a bandstop structure consists of hexangular patches and open stubs has been utilized. Finally, the wide stopband microstrip lowpass filter with cutoff frequency 2.72 GHz has been simulated, fabricated and measured. The LPF has good characteristics such as wide stopband and insertion loss lower than 0.18 dB in the passband region. The rejection level is less than -20 dB from 2.98 up to 21.3 GHz. The filter size is 10.5 mm×12.7 mm, or 0.131 λ_g× 0.158 λ_g, where λ_g is the guided wavelength. The measured and simulated results of the filter is in good agreement with each other, which show the merits of low insertion loss and wide stopband.

Realization of transmission zeros for bandpass filter using inductive-coupled stub-loaded resonators

This article proposes a bandpass filter with three controllable transmission zeros (TZs) using three inductive-coupled stub-loaded resonators (SLRs). Different from other works, the proposed SLR can create one transmission pole and one TZ. With the TZs above the passband, high stopband rejection level is achieved. Moreover, the K-inverters are realized by short-circuit stubs between two adjacent SLRs. A general synthesis method for this kind of filter is described. For verification, a filter centered at 2.44 GHz with 0.18 GHz bandwidth is designed. The measured results show that the filter has three TZs at 3.1, 3.9, and 5 GHz. With those TZs, the filter's stopband rejection level is greatly improved.

Reactively-loaded non-periodic slow-wave artificial transmission lines for stop band bandwidth enhancement: application to power splitters

This paper presents slow-wave transmission lines based on non-periodic reactive loading. Specifically, the loading elements are stepped impedance shunt stubs (SISS). By sacrificing periodicity using SISS tuned to different frequencies, multiple transmission zeros above the pass band arise, and the rejection level and bandwidth of the stop band is improved as compared with those of periodic structures. Through a proper design, it is possible to achieve compact lines, simultaneously providing the required electrical length and characteristic impedance at the design frequency (dictated by specifications), and efficiently filtering the response at higher frequencies. These lines are applied to the design of a compact power splitter with filtering capability in this work. The length of the splitter, based on a 35.35 Ω impedance inverter, is reduced by a factor of roughly two. Moreover, harmonic suppression better than 20 dB up to the fourth harmonic is achieved.