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A systematic synthesis and design procedure for coupled-resonators cavity group-delay equalizers is presented. The procedure consists of solving the approximation problem by optimization and performing cascade synthesis. The error function for the optimization is computed from the given filter's group delay and the zeros and poles of the input impedance of the equalizer. Convergence of the optimization is fast and insensitive to the initial guess even when the number of resonators is large. Two examples, together with experimental results, are presented; comparisons between the externally equalized and self-equalized filters are made. The effect of the isolation of the cascading devices (circulator or 3-dB hybrid) on the ripple of the final group-delay response is also extensively investigated. The good agreement between the theoretical simulation and the experimental results demonstrates the powerful nature and effectiveness of the proposed design procedure. Index Terms--Delay equalizer, optimization, resonators.

A model for the determination of the individual resonant frequencies and inter-resonator couplings of a system consisting of cascaded coupled resonators is presented. Measuring or computing the phase of the reflection coefficient of short-circuit terminated networks synthesizes all the inter-resonator couplings and resonant frequencies. The loading effect on the last resonator due to the unknown position of the short-circuit reference plane is accurately accounted for by a systematic method. A deterministic finite steps tuning method based on the model is developed. The method is proven successful experimentally and the noniterative nature of the method makes fully automatic tuning of filters possible. Index Terms--Computer-aided, filters, tuning.

Resonant frequencies and coupling coefficient between two combline cavities, in the presence of other cavities, are obtained accurately using the mode-matching technique. The effect of iris dimensions and position on the electric and magnetic coupling is rigorously investigated. The corresponding data for two isolated cavities are included for comparison. The adjacent and nonadjacent couplings are rigorously investigated for different configurations of three coupled cavities. A four-pole slot-coupled elliptic combline filter is designed. Index Terms--Combline filters, electromagnetic coupling.

Full-wave modelling of conductor-loaded resonators in rectangular enclosures and the associated coupling structure is presented. The modeling yields generalized scattering matrices of the cylindrical conductor-loaded resonators in rectangular waveguides. By applying short and open conditions and cascading procedure, resonant frequencies, field distributions of the resonator, and coupling coefficients between two cavities through an iris are obtained. The computed results are compared with the measured data and both are in good agreement. A four- and an eight-pole dual-mode elliptic-function filter were designed, constructed, and tested. Measured frequency responses of the filters verify the theory.

Traditional combline-filter theory based on TEM-mode coupling results in bandwidths which are too large - the increase being a function of the ground-plane spacing to wavelength ratio b/[Lambda]. As the b/[Lambda] ratio increases from 0.05 to 0.35, the bandwidth ratio (BWR), defined as actual bandwidth/TEM bandwidth, increases from unity to over 2:1. This bandwidth increase has now been confirmed by calculation of the coupling coefficient between combline resonators using mode matching. Accompanying the increased bandwidth is a considerable increase in the unloaded Q in accordance with the higher Q of the evanescent waveguide modes. A similar study carried out in the case of interdigital filters shows that these effects are much less significant. Index Terms - Bandpass filters, coaxial filters, combline filters, microwave filters, mode matching.

A rigorous method for analysis of coupled dielectric quarter wavelength combline resonators is presented. The resonant frequencies and coupling coefficients of the resonators coupled by different coupling structures are investigated. A filter design technique based on the results of numerical analysis is described. A slot coupled filter and a monoblock elliptic function filter are designed. Excellent experimental results verify the theory.

Analytic full-wave analysis and design of direct-coupled dielectric loaded bandpass filters in rectangular waveguide configuration using the T[E.sub.10] mode with a spurious-free response up to twice the operating frequency is described. The filter has no tuning screws and is small in size. Theoretical design of the filter is supported by the experimental results. Superiority of the filter over the inductive window-coupled filter is presented. Practical issues faced while building the filter are discussed. An alternative folded configuration of the filter that allows the implementation of both the canonical elliptic function as well as the Chebychev response is also presented.

A wide band, low insertion loss transition from shielded microstrip line to rectangular waveguide is analyzed by the mode matching method and the cascading procedure using generalized scattering matrices. The transition consists of a discontinuity between a ridge waveguide and the microstrip line and a ridge waveguide impedance transformer. The microstrip eigenmodes, including complex modes, are obtained by mode matching method with LSE and LSM mode expansion. The element values of the equivalent circuit for a ridge waveguide step junction is determined from its S-parameters. Computed results of a 17-22 GHz transition agree well with available experimental results. This rigorous approach provides a useful tool for the optimum design of microstrip to air filled waveguide or dielectric filled waveguide transitions.

A new simple mode matching method, called single port mode matching technique (SPMMT) for modeling rectangular waveguide T-junctions is presented. The reflection coefficient at port 2 (side arm of the T-junction) is computed with both ports 1 and 3 shorted. The three-port scattering matrix of the T-junction is obtained from nine reflection coefficient computations using different short circuit lengths in ports 1 and 3. This method is rigorous, simple, reduces the computational effort significantly and can be applied to other structures. Comparison of S-parameters with classical equivalent circuit in Marcuvitz and new equivalent circuit given by Lampariello and Lampariello is presented. Dependence of S-parameters on the slit thickness is also given. Open T-junctions are analyzed as a special case of the slit T-junction, and the results are in good agreement with experimental measurements.

In this paper, the real axis integration technique is developed to compute the oscillatory infinite spectral integrals occurring in transient scattering by a perfect electrically conducting cylinder excited by a magnetic line source. Davidenko's method is used to evaluate efficiently the complex azimuthal wavenumbers, namely, the complex zeros of the Hankel function in the order plane. The computed results of the transient Green's function compare very well with those obtained by the wavefront approximation at early time, and by the singularity expansion method at late time. The real axis integration method can be used to compute the transient response for all time.

Asymmetrical discontinuities in printed circuit traces may increase radiated power significantly over the levels resulting from symmetrical traces such as parallel lines. In this paper, an efficient full-wave space domain Galerkin moment method is developed to compute the current distribution and the radiation associated with arbitrarily shaped microstrip (or printed transmission-line) discontinuities. Several techniques are used to increase the efficiency of the method of moments (MoM) algorithm so that a circuit of moderate electrical size can be analyzed in reasonable time. These include the utilization of 1) quasi-dynamic and far-field approximations of the microstrip Green's functions where applicable, and 2) the various symmetries in the problem formulation that facilitate an efficient fill-in of the moment matrix by avoiding redundant calculations. The influence of asymmetrical currents on the radiation from some representative microstrip discontinuities is examined by appealing to the ideal structure extraction method (ISEM). Sample computed results are presented to show that the current distribution and the radiation associated with resonant size structures can be significantly higher than the regulatory limits. The MoM algorithm is validated by comparison of the computed current distribution and resonant frequencies of a microstrip transmission line with analytical results derived from quasi-TEM transmission-line theory.

Bortezomib suppressing NF‐κB activity is an effective therapy for patients with myeloma or lymphoma. However, this drug can cause adverse effects, neutropenia, and recurrent infections of herpes viruses. Among herpes viruses, HSV‐1 can reactivate to induce mortality. The important issues regarding how bortezomib diminishes neutrophils, whether bortezomib can induce HSV‐1 reactivation, and how bortezomib exacerbates HSV‐1 infection, need investigation. Using the murine model, we found that bortezomib induced HSV‐1 reactivation. Bortezomib diminished neutrophil numbers in organs of uninfected and HSV‐1‐infected mice and turned a nonlethal infection to lethal with elevated tissue viral loads. In vitro results showed that bortezomib and HSV‐1 collaborated to enhance the death and apoptosis of mouse neutrophils. The leukocyte deficiency induced by chemotherapies is generally believed to be the cause for aggravating virus infections. Here we show the potential of pathogen to exacerbate chemotherapy‐induced leukocyte deficiency. [ABSTRACT FROM AUTHOR]

Millimeter-wave H-plane diplexers/multiplexers are designed using modified H-plane waveguide T-junctions and modified inductive window bandpass filters. Modeling of the diplexers/multiplexers are performed using the full-wave mode-matching method to obtain the generalized scattering matrices of the building blocks and by the cascading procedure to provide the overall frequency response. A complete systematic optimization procedure leads to the desired diplexer/multiplexer design. The validity of employing the modified H-plane T-junctions in the diplexer/multiplexer configurations are demonstrated by the design examples. A millimeter-wave Ka upper band diplexer based on the simulated results was built and tested. Without any tuning, excellent experimental results are obtained, which verified the full-wave mode-matching-based precise design.

Herpes simplex virus type 1 (HSV-1) infection is the most common cause of sporadic, fatal encephalitis, but current understanding of how the virus interacts with cellular factors to regulate disease progression is limited. Here, we show that HSV-1 infection induced the expression of the cellular transcription factor early growth response 1 (Egr-1) in a human neuronal cell line. Egr-1 increased viral replication by activating promoters of viral productive cycle genes through binding to its corresponding sequences in the viral promoters. Mouse studies confirmed that Egr-1 expression was enhanced in HSV-1-infected brains and that Egr-1 functions to promote viral replication in embryonic fibroblasts. Furthermore, Egr-1 deficiency or knockdown of Egr-1 by a DNA-based enzyme greatly reduced the mortality of HSV-1-infected mice by decreasing viral loads in tissues. This study provides what we believe is the first evidence that Egr-1 increases the mortality of HSV-1 encephalitis by enhancing viral replication. Moreover, blocking this cellular machinery exploited by the virus could prevent host mortality. [ABSTRACT FROM AUTHOR]

Acyclovir (ACV)-resistant herpes simplex virus type 1 (HSV-1) causes severe diseases in immunocompromised patients, so identification of new therapies is needed. Interferons (IFNs) are used to treat several other viral infections in the clinic, and IFN-beta and IFN-gamma are known to cooperatively reduce wild-type HSV-1 replication in the corneas of immunocompetent mice. Because IFN-gamma has been shown to exert an antiviral effect mostly through T cells, whether combined IFN treatment can still inhibit ACV-resistant HSV-1 replication, especially in immunocompromised hosts, is unknown. The present study evaluated the efficacy of combined IFN treatment on ACV-resistant HSV-1 mutants. In vitro results showed that IFN-beta acted synergistically with IFN-gamma to inhibit HSV-1 replication in both human and mouse cell lines. Some ACV-resistant mutants were actually hypersensitive to combined IFN treatment. In vivo results showed that topical treatment with a low dose of IFN-beta plus IFN-gamma (200 U each) on mouse corneas efficiently reduced the viral loads by up to 4, 4 and 3 logs, respectively, in the eyes, trigeminal ganglia and brainstems of wild-type and also immunocompromised nude mice infected or co-infected with ACV-resistant HSV-1 in a manner independent of T cells. A highly efficient reduction in HSV acute replication by combined IFN treatment led to a dramatic decrease in subsequent virus reactivation from neural tissues, trigeminal ganglia, brainstems and spinal cords of latently infected mice. Thus, a combination of IFN-beta and IFN-gamma could be a potential treatment for ACV-resistant HSV-1 in immunocompromised patients.