One effective way to improve the state of the art is through competitions. Following the success of the Critical Assessment of protein Structure Prediction (CASP) in bioinformatics research, a number of challenge evaluations have been organized by the text-mining research community to assess and advance natural language processing (NLP) research for biomedicine. In this article, we review the different community challenge evaluations held from 2002 to 2014 and their respective tasks. Furthermore, we examine these challenge tasks through their targeted problems in NLP research and biomedical applications, respectively. Next, we describe the general workflow of organizing a Biomedical NLP (BioNLP) challenge and involved stakeholders (task organizers, task data producers, task participants and end users). Finally, we summarize the impact and contributions by taking into account different BioNLP challenges as a whole, followed by a discussion of their limitations and difficulties. We conclude with future trends in BioNLP challenge evaluations.

The full‐wave solution of multiple scattering among cylindrical vias in planar waveguides is modeled by using Foldy–Lax equations. By using the equivalence principle, the coupling among traces with many vias is decomposed into interior and exterior problems. For the interior problem, the dyadic Green's function is expressed in terms of vector cylindrical waves and waveguide modes. The Foldy–Lax equations of multiple scattering among the cylindrical vias are calculated. The waveguide modes are decoupled in the Foldy–Lax equations. The scattering matrix of coupling among vias is calculated. Numerical simulations of the scattering matrix are illustrated for several hundred vias. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 31: 201–208, 2001.

The photoaddition of naphthalene and acrylonitrile at 313 nm and in hydroxy lie solvents to afford e«ífo-7-cyano-2,3-benzobicyclo[4.2.0]octa-2,4-diene (1), the mfo-8-isomer, and 1-and 2-naphthylpropionitrile (3 and 4) is investigated. The reactive state is naphthalene Si which is determined by kinetically relating quantum yields and fluorescence quenching dependences on acrylonitrile concentration. The fluorescence quenching is proposed to occur by charge-transfer exciplex formation. Good Stern-Volmer plots are obtained for quenching in acetonitrile and rert-butyl alcohol, and the rate constant for the latter is 14 X 107 M~1 sec-1. Fluorescence of indene and anthracene is also quenched, the rate for indene being diffusion controlled. The dilution plot of reciprocal quantum yield against reciprocal acrylonitrile concentration is linear if 2,3-dimethylbuta-l,3-diene is added to prevent triplet-sensitized decomposition of 1. It is proposed that the exciplex responsible for fluorescence quenching has a polar structure, and the substituted products 3 and 4 arise from protonation of the exciplex. The evidence is that (i) the fraction of substitution increases with medium polarity and (ii) reaction in deuteroxylated solvents gives 3 and 4 labeled in the methyl groups. It is believed that indene reacts similarly and some results for the latter are presented. The exciplex structure is discussed. A correlation exists between the energetics of electron transfer and exciplex behavior for some reactions of naphthalene and benzene derivatives and acrylonitrile. This correlation may be of useful predictive value. have been published.3•5-8(1) For preliminary reports of this work see (a) R. M. Bowman and

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pulses radiated per antenna, and the number of antennas in an array. For example, if each pulse carries 1 mJ of energy, it would be permissible to couple up to 28,000 pulses into the breast over a 6 min period. In a practical UWB microwave radar imaging scenario, an array of antennas surrounds the breast volume and each element sequentially illuminates the breast. A typical array may contain on the order of 50 antennas, suggesting that up to 560 pulses could be transmitted by each antenna without exceeding the peak 1-g SA limit suggested in the IEEE exposure guideline. Note that the level of exposure of 560 pulses per antenna is much higher than we anticipate needing for this application. CONCLUSIONSWe have investigated the absorption of short (120 ps, 6-GHzcarrier) microwave pulses in anatomically realistic numerical breast phantoms in an effort to formally evaluate the safety of UWB microwave breast cancer detection technology operating in the 1-11 GHz range. We have found that the SA does not vary greatly with patient-to-patient variations in breast shape, tissue composition, or fibroglandular dielectric properties. While the specific characteristics (antenna radiation patterns, coupling media properties, etc.) of future clinical systems may differ from those assumed for this computational study, the SA values are not expected to vary significantly as a function of those characteristics. The normalized SA values reported in this paper can be scaled to account for the total number of pulses radiated and different pulse energies, providing valuable guidance in the design of future clinical systems that are in compliance with safety standards. For anticipated embodiments of such a system, we conclude that UWB microwave breast cancer detection modalities pose no health risk to the patient.

The Friedel-Crafts acetylation of methyl 2-pyrrolecarboxylate, 2-pyrrolecarboxaldehyde, and 2-pyrrolecarbonitrile was investigated and found t o give 4-substitution mainly or exclusively. The 4-acetyl-2-substituted products were converted into the 4-acetyl-2-acid, and then into 3-acetylpyrrole (methyl 3-pyrryl ketone). The Friedel-Crafts isopropylation and the bromination of both methyl 3-pyrrolecarboxylate and 3-acetylpyrrole were found to produce almost exclusively 5-substituted products.Canadian Journal of Chemistry. Volume 45, 897 (1967) IWTRODUCTIOS Some preparations and electrophilic substitution reactions of pyrroles with electronwithdrawing groups in the 3-position were undertaken as a continuation of studies on simple pyrrole derivatives. The starting materials used were 3-acetylpyrrole (methyl 3-pyrryl ketone) and methyl 3-pyrrolecarbox>-late.A good method for the preparation of the 3-ester by ring closure is kno~vn (1). Homever, the preparation (by the reaction of pyrrylmagnesium bromide with inethyl chloroformate) of large amounts of the 2-ester for Friedel-Crafts studies led to the availability of a quantity of methyl 1,3-pyrroledicarboxylate (2) as a by-product, together with the 1,2-diester (3), traces of the 1-ester, and small amounts of both 2-pyrryl 2'-pyrryl ketone and 2-pyrryl 1'-pyrryl ketone. This last compound has so far been identified only by its elemental analysis and nuclear magnetic resonance (n.m.r.) spectrum. Alethy1 1,3-pyrroledicarbox) late was easily decarboinethoxylated to the 3-ester.The reaction of pyrrylmagnesium bromide and acetic anhydride produced both 2-acetylpyrrole and the desired 3-acetylpyrrole (4), b u t the yield of the 3-ketone was low and the separation tedious. Experience with the Friedel-Crafts alkvlation reaction (5) and other electrophilic substitutions (6) suggested that Lewis acid catalyzed acetylation of pyrroles with an electron-withdrawing group in the 2-position should give mostly 4-substitution. Subsequent elimination of the group in the 2-position by conversion into an acid and decarboxylation would then give 3-acetylpyrrole (see Reaction Scheine 1).Loader (7) found that the perchloric acid catalyzed acetylation of the 2-ester gave an excellent yield of almost equal amounts of the 4-and 5-acetyl-2-esters, and Tirouflet and Fournari (8) observed similar results for the nitration of the 2-acid and 2-ketone. Both are very unselective reactions. and we felt that the FriedelCrafts acetylation should give predominantly the 4-isomer in a much more selective attack. Pre9aration of 3-Acety1;byrroleThere seem to have been few recent attempts to carry out Friedel-Crafts acylations of pyrroles which possess an electronwithdrawing group only a t the 2-position, other than the BF3-catalyzed acetylation of 1-methyl-2-nitropyrrole (9), which gave &JAG + cyt= + clfA + c y -J

maintain a front-to-end ratio of more than 10 dB in both the E-plane and H-plane. Meanwhile, the antenna gain versus frequency is also simulated and measured with two resonance bands, and the results are presented in Figure 6. As can be seen, compared with the simulations and measurements, the variations of antenna gain within the two bands are less than 0.9 dBi (band I) and 1.8 dBi (band II). In the measurements, gains of 3.6 -5.0 dBi in band I and 2.4 -5.3 dBi in band II are obtained, and a lower cross-polarization level of about Ϫ20 dB is achieved. In addition, the peak gain is 4.98 dBi at 3.1 GHz in band I and 5.3 dBi at 5.2 GHz in band II. CONCLUSIONA novel dual-band antenna with modified quasi-Yagi planar structure has been presented in this paper. In practice, three shuntconnected dipoles of various lengths, which represent the reflector, resonator, and director, respectively, were etched in the ground plane. Meanwhile, a hook-shaped balun was proposed for the feed-line design. This antenna is characterized by unidirectional end-fire radiation patterns and dual-band impedance bandwidth. With the return loss is smaller than 10 dB, the dual bands cover the ranges 2.13-3.1 GHz and 5.15-5.9 GHz. Furthermore, gain variations of 3.6 -5.0 dBi in band I and 2.4 -5.3 dBi in band II are obtained. Both the measurement and simulation results of the return-loss responses and radiation patterns agree well.The performance of the dual-band antenna includes wide bandwidth in each band, good radiation patterns in both principal planes, and a higher front-to-back pattern ratio. The differential signaling of common and differential modes of coupled interconnects are illustrated.

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