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Modeling the electromagnetic response of carbon nanotube (CNT) reinforced composites is inherently a 3-D multiscale problem that is challenging to solve in real time for nondestructive evaluation (NDE) applications. This article presents a fast and accurate full-wave electromagnetic solver based on a multilayer dyadic Green’s function approach. In this approach, we account for the effects of the dielectric slab, where the CNTs are embedded, without explicitly discretizing its interfaces. Due to their large aspect ratios, the CNTs are modeled as arbitrary thin wires (ATWs), and the method-of-moment (MoM) formulation with distributed line impedance is used to solve for their coupled currents. The accuracy of the in-house solver is validated against the commercial MoM and the finite element method (FEM) solvers over a broad range of frequencies (from 1 GHz to 10 THz) and for a wide range of dielectric slab properties. Examples of 100 nm-long vertical and horizontal CNTs embedded in a 1 $\mu \text{m}$ -thick lossy dielectric substrate are presented. The in-house solver provides more than $50\times $ speed up while solving the vertical CNT and more than $570\times $ speed up while solving the horizontal CNT than a commercial MoM solver over the GHz-to-THz frequency range. [ABSTRACT FROM AUTHOR]

A recombinant human wild-type p53-induced phosphatase (rWip1) was prepared to identify the substrate specificity of Wip1. rWip1 showed properties that were comparable to those of protein phosphatase 2Calpha in terms of affinity for Mg(super 2+), insensitivity to okadaic acid, and threonine dephosphorylation.

In this paper, we present a hybrid representation for the attachment-mode current existing on the surface of a coaxially fed rectangular microstrip patch antenna. The hybrid representation consists of a one- or two-term residue and an eigenfunction series which gives the attachment-mode current at all points on the patch surface, including the probe-to-patch junction. It is numerically demonstrated that the residue and eigenfunction series blend smoothly in the close vicinity of the Stokes region which includes the probe-to-patch junction. The Stokes region is a very narrow region over which the attachment-mode current changes rapidly. The residue and eigenfunction series are used outside and within this Stokes region, respectively. This hybrid representation can be used in either spectral- or space-domain techniques for a full-wave solution to the microstrip antenna problem. The residue series is obtained by using an equivalent contour integral representation of the infinite eigenfunction series, which subsequently reduces to the Watson transform under the assumption of a slightly lossy substrate. At or near the Stokes regions the residue series is inadequate, as it cannot model the rapidly varying junction currents there. Examination of the residue series shows that the attachment mode is a superposition of exponentially attenuated, leaky, surface-traveling modes. This hybrid representation is expected to provide the optimum trade-off between speed and accuracy for computations involving electrically large finite arrays.

On December 19, 2018, the U.S. Food and Drug Administration (FDA) granted approval to olaparib monotherapy for first‐line maintenance treatment of BRCA‐mutated (BRCAm) advanced ovarian cancer and, on May 8, 2020, expanded the indication of olaparib to include its use in combination with bevacizumab for first‐line maintenance treatment of homologous recombination deficient (HRD)–positive advanced ovarian cancer. Both these approvals were based on randomized, double‐blind, placebo‐controlled trials. Approval for olaparib monotherapy was based on the SOLO‐1 trial, comparing the efficacy of olaparib versus placebo in patients with BRCAm advanced ovarian, fallopian tube, or primary peritoneal cancer after surgical cytoreduction and first‐line platinum‐based chemotherapy. Two companion diagnostic (CDx) tests were approved with this indication: BRACAnalysis CDx, for germline BRCA1/2 alterations, and FoundationOne CDx, for BRCA1/2 alterations in tissue specimens. Approval for olaparib in combination with bevacizumab was based on the results of the PAOLA‐1 trial that compared olaparib with bevacizumab versus placebo plus bevacizumab in patients with advanced high‐grade epithelial ovarian cancer, fallopian tube, or primary peritoneal cancer after first‐line platinum‐based chemotherapy and bevacizumab. Myriad myChoice CDx was designated as a companion diagnostic device for use of olaparib plus bevacizumab combination for ovarian cancer associated with HRD‐positive status. Both trials demonstrated clinically meaningful improvements in progression‐free survival and favorable benefit‐risk profiles for the indicated populations. This article summarizes the FDA thought process and data supporting the approval of olaparib as monotherapy and in combination with bevacizumab for maintenance therapy in this setting. Implications for Practice: These approvals represent the first poly (ADP‐ribose) polymerase inhibitor, alone or in combination with bevacizumab, approved in first‐line maintenance treatment of women with advanced ovarian cancer after cytoreductive surgery and chemotherapy. In patients with BRCA‐mutated tumors, olaparib monotherapy demonstrated a 70% reduction in the risk of disease progression or death compared with placebo, and olaparib in combination with bevacizumab demonstrated a 67% reduction in the risk of disease progression or death compared with bevacizumab alone in homologous recombination deficient–positive tumors. These approvals represent a major advance for the treatment of women with advanced ovarian cancer who are in complete or partial response after their initial platinum‐based chemotherapy. Despite the best standard of care for newly diagnosed advanced ovarian cancer, approximately 70% of women relapse within the first 3 years. This article presents the FDA's rationale for approval of olaparib for the maintenance therapy of patients with deleterious or suspected deleterious germline or somatic BRCA‐mutated advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in complete or partial response to first‐line platinum‐based chemotherapy. [ABSTRACT FROM AUTHOR]

Plasmonic nanoantennas are typically designed with RF-inspired rigorous parametric optimization processes that lack proper physical insights. In this article, we demonstrate a systematic optimization approach for nanoantennas based on characteristic mode analysis (CMA). A complex geometry, designated as split-ring two-wire antenna (SRA), is selected and optimized using the CMA technique. CMA identifies the dominant modes of the structure at the frequency of interest as well as explains the dependence of the modes on the structure’s shape, size and material properties. These insights from CMA have been used in this study to efficiently optimize SRA shape, size, and material which yield more than 700% near-field intensity enhancement (NFIE) at the desired operating frequency. This proposed CMA-based optimization method can be adapted easily for many other nanoantenna applications, facilitating the development of improved nanostructures. [ABSTRACT FROM AUTHOR]

In this paper we examine the effect of truncating an infinite asymptotic series for the Hankel function used in microstrip antenna calculations. In particular, the accuracy of this truncated asymptotic expansion of the Hankel function is examined from a numerical viewpoint. This expansion has been used in the literature to obtain closed-form expressions for the microstrip Green's function for subsequent use in calculating mutual coupling between elements in a microstrip array. In this paper, we show that truncating the asymptotic series for the Hankel function could lead to severe unexpected errors for those values of the argument where the asymptotic expansion is normally expected to be valid. This is known as the Stokes phenomenon and has generally remained obscure in the literature. Since the large argument of the Hankel function is shown to be related to the lateral separation between two antennas, the results presented here have a particular bearing in calculating mutual coupling between widely separated elements in electrically large microstrip arrays.

Studies of a recombinant human Wip1 catalytic domain (rWip1) conducted by measuring the kinetic parameters for variants of the ATM(1981pS) phosphopeptide, AFEEGpSQSTTI is discussed. The findings from the studies could be useful to regulate physiological substrates by Wip1 and to develop selective anticancer drugs.

Five HIV-1 reverse transcriptase variants containing tyrosine analogues at position 115 of their p66 subunit are evaluated. The findings are discussed within the context of detailed structural models of HIV-1 reverse transcriptase ternary complexes containing this amino acid substitution that reveal probable mechanisms of the observed catalytic rate changes.

In this article, the effect of reactive loading on a probe-fed, single-layer, U-slot loaded microstrip antenna is investigated using the theory of characteristic modes (TCM). A detailed analysis of reactive loading due to feed location and arm-angle variation is presented. The eigenvalue behavior of the characteristic modes can be modified by varying reactive loading on the U-slot antenna. Thus, it is possible to control certain modes such that they resonate in the desired frequency band. These modes can then be effectively excited to achieve the desired antenna performance. In addition, reactive loading helps to move the impedance loop to the center of the Smith chart. Optimized reactive loading has been shown to produce a modified U-slot structure without any increased cost or complexity. The optimized loaded antenna is wide-band, with a relatively stable radiation pattern. [ABSTRACT FROM AUTHOR]

The method of moments (MOM) analysis of probe-fed rectangular microstrip patches requires the inclusion of a probe-to-patch attachment mode-expansion function when the substrate thickness d [is greater than or equal to] O.02??, where ?? is the free-space wavelength. The results for the input impedance showed increased divergence with measurements when the attachment mode was omitted from the full-wave analysis. The attachment mode can be expressed as an infinite eigenfunction series that increases the fill time of the impedance matrix in an MoM analysis. In an earlier investigation, the infinite eigenfunction series was reduced to a residue series that required one or two terms compared to about 55 terms for the eigenfunction series. In this paper, the convergence properties of the eigenfunction and residue series are investigated in view of rigorous MoM analysis. The relative errors resulting from replacing the eigenfunction by the residue series for the attachment mode, are compared by numerically evaluating a class of two-dimensional (2-D) spatial integrals shown to be closely related to the elements of an MoM impedance matrix. Additionally, the computation times for the evaluation of these integrals for the two forms of the attachment mode-expansion function are also included. Based on the superior convergence properties of the residue series for the attachment mode-expansion function, it is mathematically justified that this form can readily be used for analytic reduction of the spatial, reaction integrals from four to 2-D forms. This feature allows further reduction of the fill time of the MoM impedance matrix, suggesting the possibility of developing an efficient space-domain MoM technique for modeling of wide-band microstrip antennas. Index Terms--Method of moments, microstrip antennas.

The Theory of Characteristic Modes (TCM) is proposed as a systematic approach to antenna design to achieve the goal of finding the antenna structure with optimum broadband behavior. This theory provides a physical insight to the radiating nature of microstrip patch antennas and reduces the design optimization time. In this work, the resonant behavior of the highly radiating structure of the single U-slot rectangular patch on a single-layer εr = 4.4 substrate is analyzed using TCM. Modal analysis of this single-layer structure with different single feed excitations concludes that VSWR ≤ 2 impedance bandwidth in the order of 96% can be achieved with a single T-probe feed. Experimental results, included here, show VSWR ≤ 2 impedance bandwidth in the order of 71%. [ABSTRACT FROM AUTHOR]

Ultra-wideband (UWB) phased arrays are increasingly used in radar and medical applications. Mutual coupling reduction between the phased array elements is critical in achieving good scan bandwidth. This study investigates the mutual coupling of a UWB U-slot microstrip patch 2-element array to find the patch orientation and U-slot topology with the least mutual coupling. Electromagnetic (EM) simulation results indicate that, for εr = 2.2 substrate, diamond patch orientation with opposite U-slot topology has the least coupling between the array elements. Results also indicate that the current density distribution on the microstrip patch has an effect on mutual coupling between the array elements. Results show good agreement between MoM and FEM EM solvers. [ABSTRACT FROM AUTHOR]

Graphene flakes (GFs) in real composites are rarely perfectly flat, and often exhibit complicated crumpled shapes. Therefore, the goal of this paper was to quantify the electromagnetic scattering characteristics of individual crumpled GFs with shapes resembling those found in real composites. The extinction cross sections of tens of GFs, with different sizes and various levels of crumpleness, were calculated using multiple independent solvers. The results show that resonances in the extinction cross section spectrum decrease in amplitude as the GFs become more crumpled. Moreover, some crumpled GFs exhibited a broader resonance than that of perfectly flat GFs. To explain these results, we used a characteristic mode analysis to decompose the graphene surface currents into a set of fundamental currents or modes. For perfectly flat square GFs, the vertical and horizontal modes were found to overlap and resonate at the same frequencies. However, as the GFs became more crumpled, the horizontal/vertical symmetry broke down causing the corresponding modes to separate and resonate at different frequencies leading to an overall broader bandwidth. These results attest to the importance of modeling the exact shape of GFs to accurately characterize their electromagnetic response. [ABSTRACT FROM AUTHOR]

The need for low-profile and ultra-wideband (UWB) antennas is rising in wireless communication and medical applications. The method of dimensional invariance, which is a class of U-slot patch design methods, is utilized to realize an initial, low-profile, wideband design. Building on this initial wideband design, this study establishes ideal L-probe feed dimensions through extensive parametric study on εr = 2.2 and 4.5 substrates to propose empirical guidelines for the design of L-probe feeds which yield first-pass optimum impedance bandwidth. The established ideal L-probe dimensions, after further extrapolation, are used successfully on other substrates, εr = 3.27, 6.0 and 9.2, for the design of first-pass L-probe feeds which yield impedance bandwidth over 55%, 60%, and 53%, respectively. The results of three commercially available EM simulation solvers show good agreement [ABSTRACT FROM AUTHOR]

In this paper, characteristic mode analysis (CMA) of three empirical design techniques for the probe-fed, symmetrically located, U-slot microstrip patch antenna, on a single-layer grounded substrate, is presented with supporting experimental data. The first method, resonant frequency (ResF), utilizes the existence of the four distinct ResFs, while the second one, dimensional invariance (DI), relies on the property of DI, for the design of the U-slot microstrip patch. In both these methods, the optimization of the probe location is necessary for further enhancement of the 10-dB return loss bandwidth. The third method, dimensionally invariant ResF, that optimally combines the features of the previous two is developed here and shown to yield better bandwidth performance with minimal or no probe location optimization, and hence is superior to the other two for rapid prototyping. CMA is carried out for critical parameters, such as substrate electrical thickness, slot width, probe radius, and feed location variations, to assess their dominant influence on the characteristics of the U-slot microstrip patch antenna. [ABSTRACT FROM AUTHOR]

Shuttling of proteins between nucleus and cytoplasm in mammalian cells is facilitated by the presence of nuclear localization signals (NLS) and nuclear export signals (NES), respectively. However, we have found that Tus, an E. coli replication fork arresting protein, contains separate sequences that function efficiently as NLS and NES in mammalian cell lines, as judged by cellular location of GFP-fusion proteins. The NLS was localized to a short stretch of 9 amino acids in the carboxy-terminus of Tus protein. Alterations of any of these basic amino acids almost completely abolished the nuclear targeting. The NES comprises a cluster of leucine/hydrophobic residues located within 21 amino acids at the amino terminus of Tus. Finally, we have shown that purified GFP-Tus fusion protein or GFP-Tus NLS fusion protein, when added to the culture media, was internalized very efficiently into mammalian cells. Thus, Tus is perhaps the first reported bacterial protein to possess both NLS and NES, and has the capability to transduce protein into mammalian cells. [ABSTRACT FROM AUTHOR]

We describe a novel, simple and low-cost protein microarray strategy wherein the microarrays are generated by printing expression ready plasmid DNAs onto slides that can be converted into protein arrays on-demand. The printed expression plasmids serve dual purposes as they not only direct the synthesis of the protein of interest; they also serve to capture the newly synthesized proteins through a high affinity DNA-protein interaction. To accomplish this we have exploited the high-affinity binding (∼3-7x10-13 M) of E. coli Tus protein to Ter, a 20 bp DNA sequence involved in the regulation of E. coli DNA replication. In our system, each protein of interest is synthesized as a Tus fusion protein and each expression construct directing the protein synthesis contains embedded Ter DNA sequence. The embedded Ter sequence functions as a capture reagent for the newly synthesized Tus fusion protein. This ''all DNA'' microarray can be converted to a protein microarray on-demand without need for any additional capture reagent.. [ABSTRACT FROM AUTHOR]

The soluble expression of heterologous proteins in Escherichia coli remains a serious bottleneck in protein production. Although alteration of expression conditions can sometimes solve the problem, the best available tools to date have been fusion tags that enhance the solubility of expressed proteins. However, a systematic analysis of the utility of these solubility fusions has been difficult, and it appears that many proteins react differently to the presence of different solubility tags. The advent of high-throughput structural genomics programs and advances in cloning and expression technology afford us a new way to compare the effectiveness of solubility tags. This data should allow us to better predict the effectiveness of tags currently in use, and might also provide the information needed to identify new fusion tags. [Copyright &y& Elsevier]

Abstract: Production of soluble recombinant proteins is vital for structure–function analysis and therapeutic applications. Unfortunately, when expressed in a heterologous host, such as Escherichia coli, most proteins are expressed as insoluble aggregates. Two new fusion partners have been identified to address these solubility problems. One of the tags was derived from a bacteriophage T7 protein kinase and the other one from a small E. coli chaperone, Skp. We have expressed a panel of insoluble human proteins including Hif1α, IL13, and folliculin as fusion proteins using these tags. Most of these fusion proteins were able to be expressed in a soluble form and could be purified by virtue of a Strep-tag II installed at the amino-terminal end of the fusion partners. In addition, we show that some of these proteins remained soluble after removal of the fusion tags by a site-specific protease. The results with these tags compare favorably to results with the most commonly used solubility tags described in the literature. Therefore, these two new fusion tags have the potential to express soluble proteins when fused with many recalcitrant proteins. [Copyright &y& Elsevier]