History of the Electrical Insulation Conference

This Electrical Insulation Conference (EIC) history gives a wide-ranging documentation of the EIC, from its inception in 1958 to the present. The EIC's inception was driven by advances in polymer technology. The EIC awards are outlined as is co-sponsorship of the conference.     

Vinorelbine as neoadjuvant chemotherapy in advanced cervical carcinoma

PURPOSE: To evaluate the efficacy and toxicity of vinorelbine (VNB) as single-agent neoadjuvant chemotherapy in advanced cervical carcinoma (ACC). PATIENTS AND METHODS: Between December 1993 and October 1995, 43 untreated patients with stages IIB to IVA squamous cell cervical cancer were entered onto this study. Forty-two patients are assessable for response and 43 for toxicity. The median age was 46 years (range, 28 to 65). Distribution by stages (International Federation of Gynecology and Obstetrics [FIGO]) was as follows: IIB, 18 patients; IIIA, one; IIIB, 19; and IVA, five. Therapy consisted of VNB 30 mg/m2 by 20-minute intravenous (IV) infusion repeated weekly for 12 injections and followed by radical surgery if feasible or definitive radiotherapy. Both staging and response assessment were performed by a multidisciplinary team. RESULTS: One patient was considered not assessable for response. A total of 493 cycles of therapy were administered and objective remissions were observed in 19 of 42 patients (45%; 95% confidence interval, 30% to 60%). Two patients (5%) had a complete response (CR) and 17 (40%) a partial response (PR); no change (NC) was observed in 16 (38%) and progressive disease (PD) in seven (17%). Six of 19 patients (32%) who achieved objective responses (ORs) underwent surgery. The median time to failure and median survival time have not been reached yet. There were no therapy-related deaths. The dose-limiting toxicity was myelosuppression. Leukopenia occurred in 35 patients (81%) and was grade 3 or 4 in seven (17%). Twelve patients (28%) developed peripheral neuropathy, while myalgias occurred in 10 (23%). Constipation was observed in nine patients (21%), one with a prolonged ileum. Phlebitis was recorded in 18 patients (41%). In contrast, emesis and mucositis were rarely observed. No patient developed alopecia grade 3. By the end of the twelfth course of treatment, the average received dose-intensity was 85.4% of that projected. CONCLUSION: VNB is an active drug against ACC with moderate toxicity. Its activity is among the highest reported for single agents. Further evaluation in association with other agents is clearly justified.     

Atlantic Salmon Mucins Inhibit LuxS-Dependent A. Salmonicida AI-2 Quorum Sensing in an N-Acetylneuraminic Acid-Dependent Manner

One of the most important bacterial diseases in salmonid aquaculture is furunculosis, caused by Aeromonas salmonicida. Bacterial communication through secreted autoinducer signals, quorum sensing, takes part in the regulation of gene expression in bacteria, influencing growth and virulence. The skin and mucosal surfaces, covered by a mucus layer, are the first point of contact between fish and bacteria. Mucins are highly glycosylated and are the main components of mucus. Here, we validate the Vibrio harveyi BB170 bioreporter assay for quantifying A. salmonicida quorum sensing and study the effects of Atlantic salmon mucins as well as mono- and disaccharides on the AI-2 levels of A. salmonicida. Atlantic salmon mucins from skin, pyloric ceca, proximal and distal intestine reduced A. salmonicida AI-2 levels. Among the saccharides abundant on mucins, fucose, N-acetylneuraminic acid and GlcNAcβ1-3Gal inhibited AI-2 A. salmonicida secretion. Removal of N-acetylneuraminic acid, which is the most abundant terminal residue on mucin glycans on Atlantic salmon mucins, attenuated the inhibitory effects on AI-2 levels of A. salmonicida. Deletion of A. salmonicida luxS abolished AI-2 production. In conclusion, Atlantic salmon mucins regulate A. salmonicida quorum sensing in a luxS and N-acetylneuraminic acid-dependent manner.     

Joint Multi-Frequency Beam Shaping and Steering via Space–Time-Coding Digital Metasurfaces

Digital programmable metasurfaces provide a very powerful and versatile platform for implementing spatio-temporal modulation schemes that are of great interest within the emerging framework of space–time metastructures. In particular, space–time-coding digital metasurfaces have been successfully applied to advanced wavefront-manipulations in both the spatial and spectral domains. However, conventional space–time-coding schemes do not allow the joint syntheses of the transmission/scattering angular responses at multiple frequencies, which are potentially useful in a variety of applications of practical interest. Here, a strategy is put forward to lift this limitation, thereby enabling joint multi-frequency beam shaping and steering, that is, the independent and simultaneous syntheses of prescribed scattering patterns at given harmonic frequencies. The proposed approach relies on a more sophisticated space–time coding, with suitably designed, and temporally intertwined coding sub-sequences, which effectively disentangles the joint multi-frequency syntheses. The power and versatility of the approach are illustrated via a series of representative application examples, including multi-beam, diffuse-scattering, and orbital-angular-momentum patterns. Theoretical predictions are experimentally validated by means of microwave measurements. The outcomes of this study hold promising potentials for applications to future imaging, information, and mobile-communication systems.     

Radiation properties of one-dimensional random-like antenna arrays based on Rudin-Shapiro sequences

The development of exotic new materials, such as metamaterials, has created strong interest within the electromagnetics (EM) community for possible new phenomenologies and device applications, with particular attention to periodicity-induced phenomena, such as photonic bandgaps. Within this context, motivated by the fairly recent discovery in X-ray crystallography of "quasi-crystals", whose diffraction patterns display unusual characteristics that are associated with "aperiodic order", we have undertaken a systematic study of how these exotic effects manifest themselves in the radiation properties of aperiodically configured antenna arrays. The background for these studies, with promising example configurations, has been reported in a previous publication [V. Pierro et al., IEEE Trans. Antennas Propag., vol. 53, pp. 635-644, Feb. 2005]. In this paper, we pay attention to various configurations generated by Rudin-Shapiro (RS) sequences, which constitute one of the simplest conceivable examples of deterministic aperiodic geometries featuring random-like (dis)order. After presentation and review of relevant background material, the radiation properties of one-dimensional RS-based antenna arrays are analyzed, followed by illustrative numerical parametric studies to validate the theoretical models. Design parameters and potential practical applications are also given attention.     

Radiation properties of planar antenna arrays based on certain categories of aperiodic tilings

Two-dimensional aperiodic tilings are collections of polygons, devoid of any translational symmetries, capable of covering a plane without gaps and overlaps. Although aperiodic, these structures can exhibit order and symmetry in an extended sense. In this paper, we study the radiation properties of planar antenna arrays based on certain categories of two-dimensional aperiodic tilings that illustrate diverse aspects of aperiodic order. Background material on aperiodic tilings and their known electromagnetic properties is reviewed. Results are illustrated to highlight the effects of aperiodic order in the antenna array radiation properties. Potential applications are also envisaged     

Strategies for the Diffusion of Innovations on Social Networks

We investigate the spread of innovations on a social network. The network consists of agents that are exposed to the introduction of a new product. Consumers decide whether or not to buy the product based on their own preferences and the decisions of their neighbors in the social network. We use and extend concepts from the literature on epidemics and herd behavior to study this problem. The central question of this paper is whether firms can learn about the network structure and consumer characteristics when only limited information is available, and use this information to evolve a successful directed-advertising strategy. In order to do so, we extend existing models to allow for heterogeneous agents and both positive and negative externalities. The firm can learn a directed-advertising strategy that takes into account both the topology of the social consumer network and the characteristics of the consumer. Such directed-advertising strategies outperform random advertising.     

Deactivation, Regeneration, and Stable Performance of a PtMoRe Water Gas Shift Catalyst for On-Site Hydrogen Generation: Part 2

This paper analyzes the mechanism of deactivation and methods of regeneration of a PtMoRe water gas shift catalyst supported on a stabilized zirconia. Although this catalyst initially possesses high activity below 250 °C, a decrease in CO conversion ranging from 10 to 50% was observed over a period of 60 h. To determine the mechanism responsible for the decay, a series of activity tests and high resolution transmission electron microscopy analyses were done. Experimental results revealed the existence of stable and unstable operating regimes that depend on the reaction temperature, CO concentration, and H₂O/H₂. The high initial activity of this catalyst relies upon a synergetic relationship between the platinum, molybdenum, and rhenium which form an alloy generating the catalytically active phase. Based on our experimental results, we have concluded water contained in the feed gas oxidizes the Mo/Re metals, disrupts this synergy (de-alloys), and deactivates the catalyst. While not completely understood, CO is required for this oxidation mechanism to occur and possible explanations are discussed. Heating the catalyst in a hydrogen or reformate gas reduces the oxides back to metals, reforms the PtMoRe alloy, and restores the activity of the catalyst. Conditions for stable performance are consistent with use as a mid-temperature range water gas shift catalyst for on-site hydrogen generation.