Super-resolution properties of the Spherical Geodesic Waveguides using the perfect drain

Perfect drain for the Maxwell Fish Eye (MFE) is a nonmagnetic dissipative region placed in the focal point to absorb all the incident radiation without reflection or scattering. The perfect drain was recently designed as a material with complex permittivity ? that depends on frequency. However, this material is only a theoretical material, so it can not be used in practical devices. Recently, the perfect drain has been claimed as necessary to achieve super-resolution [Leonhard 2009, New J. Phys. 11 093040], which has increased the interest for practical perfect drains suitable for manufacturing. Here, we analyze the superresolution properties of a device equivalent to the MFE, known as Spherical Geodesic Waveguide (SGW), loaded with the perfect drain. In the SGW the source and drain are implemented with coaxial probes. The perfect drain is realized using a circuit (made of a resistance and a capacitor) connected to the drain coaxial probes. Superresolution analysis for this device is done in Comsol Multiphysics. The results of simulations predict the superresolution up to ? /3000 and optimum power transmission from the source to the drain.

Design of spherical symmetric gradient index lenses

Spherical symmetric refractive index distributions also known as Gradient Index lenses such as the Maxwell-Fish-Eye (MFE), the Luneburg or the Eaton lenses have always played an important role in Optics. The recent development of the technique called Transformation Optics has renewed the interest in these gradient index lenses. For instance, Perfect Imaging within the Wave Optics framework has recently been proved using the MFE distribution. We review here the design problem of these lenses, classify them in two groups (Luneburg moveable-limits and fixed-limits type), and establish a new design techniques for each type of problem.

Perfect imaging of point sources with positive refraction

The capability of a device called the Spherical Geodesic Waveguide (SGW) to produce images with details below the classic Abbe diffraction limit (super-resolution) is analyzed here. The SGW is an optical system equivalent (by means of Transformation Optics) to the Maxwell Fish Eye (MFE) refractive index distribution. Recently, it has been claimed that the necessary condition to get super-resolution in the MFE and the SGW is the use of a Perfect Point Drain (PPD). The PPD is a punctual receptor placed in the focal point that absorbs the incident wave, without reflection or scattering. A microwave circuit comprising three elements, the SGW, the source and the drain (two coaxial lines loaded with specific impedances) is designed and simulated in COMSOL. The super-resolution properties have been analyzed for different position of the source and drain and for two different load impedances: the PPD and the characteristic line impedance. The results show that in both cases super-resolution occurs only for discrete number of frequencies. Out of these frequencies, the SGW does not show SR in the analysis carried out.

Extreme super-resolution using the spherical geodesic waveguide

Leonhardt demonstrated (2009) that the 2D Maxwell Fish Eye lens (MFE) can focus perfectly 2D Helmholtz waves of arbitrary frequency, i.e., it can transport perfectly an outward (monopole) 2D Helmholtz wave field, generated by a point source, towards a "perfect point drain" located at the corresponding image point. Moreover, a prototype with λ/5 superresolution (SR) property for one microwave frequency has been manufactured and tested (Ma et al, 2010). Although this prototype has been loaded with an impedance different from the "perfect point drain", it has shown super-resolution property. However, neither software simulations nor experimental measurements for a broad band of frequencies have yet been reported. Here we present steady state simulations for two cases, using perfect drain as suggested by Leonhardt and without perfect drain as in the prototype. All the simulations have been done using a device equivalent to the MFE, called the Spherical Geodesic Waveguide (SGW). The results show the super-resolution up to λ/3000, for the system loaded with the perfect drain, and up to λ/500 for a not perfect load. In both cases super-resolution only happens for discrete number of frequencies. Out of these frequencies, the SGW does not show super-resolution in the analysis carried out.

On the design of spherical gradient index lenses

Classical spherical gradient index (GRIN) lenses (such as Maxwell Fish Eye lens, Eaton lens, Luneburg lens, etc.) design procedure using the Abel integral equation is reviewed and reorganized. Each lens is fully defined by a function called the angle of flight which describes the ray deflection through the lens. The radial refractive index distribution is obtained by applying a linear integral transformation to the angle of flight. The interest of this formulation is in the linearity of the integral transformation which allows us to derive new solutions from linear combinations of known lenses. Beside the review of the classical GRIN designs, we present a numerical method for GRIN lenses defined by the Abel integral equation with fixed limits, which is an ill-posed problem.

Experimental evidence for super-resolution in the spherical geodesic waveguide

The previous publications (Miñano et al, 2011 and Gonzalez et al, 2012) have shown that using a Spherical Geodesic Waveguide (SGW) it can be achieved the super-resolution up to λ/3000, which is far below the classic Abbe diffraction limit, close to a set of discrete microwave frequencies. The SGW was designed and simulated in COMSOL as a thin geodesic waveguide bounded by an ideal and lossless metal. Herein we present the experimental results for a manufactured SGW, slightly modified due to fabrication requirements, showing the super-resolution up to λ/105.

Experimental evidence of super-resolution better than lambda/105 with positive refraction

Super-resolution (SR) systems surpassing the Abbe diffraction limit have been theoretically and experimentally demonstrated using a number of different approaches and technologies: using materials with a negative refractive index, utilizing optical super-oscillation, using a resonant metalens, etc. However, recently it has been proved theoretically that in the Maxwell fish-eye lens (MFE), a device made of positive refractive index materials, the same phenomenon takes place. Moreover, using a simpler device equivalent to the MFE called the spherical geodesic waveguide (SGW), an SR of up to λ/3000 was simulated in COMSOL. Until now, only one piece of experimental evidence of SR with positive refraction has been reported (up to λ/5) for an MFE prototype working at microwave frequencies. Here, experimental results are presented for an SGW prototype showing an SR of up to λ/105. The SGW prototype consists of two concentric metallic spheres with an air space in between and two coaxial ports acting as an emitter and a receiver. The prototype has been analyzed in the range 1 GHz to 1.3 GHz.

Estratégias de enfrentamento utilizadas por praticantes de Artes Marciais

O presente estudo teve por objetivos, descrever as estratégias de enfrentamento utilizadas por praticantes de artes marciais; relacionar as estratégias de enfrentamento utilizadas por praticantes iniciantes em artes marciais com aquelas utilizadas por praticantes formados; e relacionar as estratégias de enfrentamento ao tempo de pratica das artes marciais. Participaram 94 sujeitos do sexo masculino, numa faixa etária de 15 até 56 anos, com nível de instrução médio, praticantes de: Kung Fu Chinês, Kung Fu Vietnamita (Qwan Ki Do), Taekwondo e Karatê, artes marciais de contato semelhantes tecnicamente. Foram distribuídos em dois grupos: Grupo 1 67 praticantes com tempo de pratica superior a 12 meses podendo ser ou não formados faixa-preta, ou seja, aqueles que tiveram experiência, treino e estudo necessários exigidos dentro de sua modalidade marcial e entre esses estão incluídos também os que se formaram e lecionam e o Grupo 2 - 27 praticantes chamados iniciantes, com tempo de prática compreendido até 12 meses. Utilizou-se a Escala de Modos de Enfrentamento de Problemas: EMEP e um Questionário. Os dados foram submetidos ao Statistical Package for Social Science (SPSS), versão 15.0 para Windows, para analise estatística descritiva e r-Person. Os resultados indicaram que quanto ao uso de estratégias de enfrentamento utilizadas por estes praticantes de artes marciais não foram encontradas diferenças significativas entre os dois diferentes grupos. Numa compreensão conforme o ponto médio da escala pôde-se observar que as estratégias de enfrentamento focado no problema e busca de suporte social, apresentaram uma média de utilização (estável); isso significa que os sujeitos utilizam-nas dentro de um padrão adequado em ambos os grupos. É interessante também observar que com relação à estratégias focadas na emoção, estas estão entre as menores médias observadas. Isto significa que os sujeitos praticantes de artes marciais utilizam menos estas estratégias, denotando pouco mais de controle emocional em relação às outras estratégias. Outros aspectos interessantes, dizem respeito a um índice significativo, ou uma relação entre os anos de ensino e busca de suporte social entre os sujeitos do Grupo 1 (formados que lecionam). Pode-se entender que quanto mais tempo essas pessoas se dedicam ao ensino, mais estratégias de suporte social eles desenvolvem. De um ponto de vista lógico, pode-se dizer que essa convivência com alunos durante os anos que o sujeito leciona, também favorece um melhor contato social.

Estratégias de enfrentamento utilizadas por praticantes de Artes Marciais

O presente estudo teve por objetivos, descrever as estratégias de enfrentamento utilizadas por praticantes de artes marciais; relacionar as estratégias de enfrentamento utilizadas por praticantes iniciantes em artes marciais com aquelas utilizadas por praticantes formados; e relacionar as estratégias de enfrentamento ao tempo de pratica das artes marciais. Participaram 94 sujeitos do sexo masculino, numa faixa etária de 15 até 56 anos, com nível de instrução médio, praticantes de: Kung Fu Chinês, Kung Fu Vietnamita (Qwan Ki Do), Taekwondo e Karatê, artes marciais de contato semelhantes tecnicamente. Foram distribuídos em dois grupos: Grupo 1 67 praticantes com tempo de pratica superior a 12 meses podendo ser ou não formados faixa-preta, ou seja, aqueles que tiveram experiência, treino e estudo necessários exigidos dentro de sua modalidade marcial e entre esses estão incluídos também os que se formaram e lecionam e o Grupo 2 - 27 praticantes chamados iniciantes, com tempo de prática compreendido até 12 meses. Utilizou-se a Escala de Modos de Enfrentamento de Problemas: EMEP e um Questionário. Os dados foram submetidos ao Statistical Package for Social Science (SPSS), versão 15.0 para Windows, para analise estatística descritiva e r-Person. Os resultados indicaram que quanto ao uso de estratégias de enfrentamento utilizadas por estes praticantes de artes marciais não foram encontradas diferenças significativas entre os dois diferentes grupos. Numa compreensão conforme o ponto médio da escala pôde-se observar que as estratégias de enfrentamento focado no problema e busca de suporte social, apresentaram uma média de utilização (estável); isso significa que os sujeitos utilizam-nas dentro de um padrão adequado em ambos os grupos. É interessante também observar que com relação à estratégias focadas na emoção, estas estão entre as menores médias observadas. Isto significa que os sujeitos praticantes de artes marciais utilizam menos estas estratégias, denotando pouco mais de controle emocional em relação às outras estratégias. Outros aspectos interessantes, dizem respeito a um índice significativo, ou uma relação entre os anos de ensino e busca de suporte social entre os sujeitos do Grupo 1 (formados que lecionam). Pode-se entender que quanto mais tempo essas pessoas se dedicam ao ensino, mais estratégias de suporte social eles desenvolvem. De um ponto de vista lógico, pode-se dizer que essa convivência com alunos durante os anos que o sujeito leciona, também favorece um melhor contato social.

Induction of solid tumor differentiation by the peroxisome proliferator-activated receptor-γ ligand troglitazone in patients with liposarcoma

Agonist ligands for the nuclear receptor peroxisome proliferator-activated receptor-γ have been shown to induce terminal differentiation of normal preadipocytes and human liposarcoma cells in vitro. Because the differentiation status of liposarcoma is predictive of clinical outcomes, modulation of the differentiation status of a tumor may favorably impact clinical behavior. We have conducted a clinical trial for treatment of patients with advanced liposarcoma by using the peroxisome proliferator-activated receptor-γ ligand troglitazone, in which extensive correlative laboratory studies of tumor differentiation were performed. We report here the results of three patients with intermediate to high-grade liposarcomas in whom troglitazone administration induced histologic and biochemical differentiation in vivo. Biopsies of tumors from each of these patients while on troglitazone demonstrated histologic evidence of extensive lipid accumulation by tumor cells and substantial increases in NMR-detectable tumor triglycerides compared with pretreatment biopsies. In addition, expression of several mRNA transcripts characteristic of differentiation in the adipocyte lineage was induced. There was also a marked reduction in immunohistochemical expression of Ki-67, a marker of cell proliferation. Together, these data indicate that terminal adipocytic differentiation was induced in these malignant tumors by troglitazone. These results indicate that lineage-appropriate differentiation can be induced pharmacologically in a human solid tumor.

The design, computer modeling, solution structure, and biological evaluation of synthetic analogs of bryostatin 1

The bryostatins are a unique family of emerging cancer chemotherapeutic candidates isolated from marine bryozoa. Although the biochemical basis for their therapeutic activity is not known, these macrolactones exhibit high affinities for protein kinase C (PKC) isozymes, compete for the phorbol ester binding site on PKC, and stimulate kinase activity in vitro and in vivo. Unlike the phorbol esters, they are not first-stage tumor promoters. The design, computer modeling, NMR solution structure, PKC binding, and functional assays of a unique class of synthetic bryostatin analogs are described. These analogs (7b, 7c, and 8) retain the putative recognition domain of the bryostatins but are simplified through deletions and modifications in the C4-C14 spacer domain. Computer modeling of an analog prototype (7a) indicates that it exists preferentially in two distinct conformational classes, one in close agreement with the crystal structure of bryostatin 1. The solution structure of synthetic analog 7c was determined by NMR spectroscopy and found to be very similar to the previously reported structures of bryostatins 1 and 10. Analogs 7b, 7c, and 8 bound strongly to PKC isozymes with Ki = 297, 3.4, and 8.3 nM, respectively. Control 7d, like the corresponding bryostatin derivative, exhibited weak PKC affinity, as did the derivative, 9, lacking the spacer domain. Like bryostatin, acetal 7c exhibited significant levels of in vitro growth inhibitory activity (1.8–170 ng/ml) against several human cancer cell lines, providing an important step toward the development of simplified, synthetically accessible analogs of the bryostatins.

Antibody catalysis of peptidyl-prolyl cis-trans isomerization in the folding of RNase T1

An antibody generated to an α-keto amide containing hapten 1 catalyzes the cis-trans isomerization of peptidyl-prolyl amide bonds in peptides and in the protein RNase T1. The antibody-catalyzed peptide isomerization reaction showed saturation kinetics for the cis-substrate, Suc-Ala-Ala-Pro-Phe-pNA, with a kcat/Km value of 883 s−1⋅M−1; the reaction was inhibited by the hapten analog 13 (Ki = 3.0 ± 0.4 μM). Refolding of denatured RNase T1 to its native conformation also was catalyzed by the antibody, with the antibody-catalyzed folding reaction inhibitable both by the hapten 1 and hapten analog 13. These results demonstrate that antibodies can catalyze conformational changes in protein structure, a transformation involved in many cellular processes.

α1-Antitrypsin Portland, a bioengineered serpin highly selective for furin: Application as an antipathogenic agent

The important role of furin in the proteolytic activation of many pathogenic molecules has made this endoprotease a target for the development of potent and selective antiproteolytic agents. Here, we demonstrate the utility of the protein-based inhibitor α1-antitrypsin Portland (α1-PDX) as an antipathogenic agent that can be used prophylactically to block furin-dependent cell killing by Pseudomonas exotoxin A. Biochemical analysis of the specificity of a bacterially expressed His- and FLAG-tagged α1-PDX (α1-PDX/hf) revealed the selectivity of the α1-PDX/hf reactive site loop for furin (Ki, 600 pM) but not for other proprotein convertase family members or other unrelated endoproteases. Kinetic studies show that α1-PDX/hf inhibits furin by a slow tight-binding mechanism characteristic of serpin molecules and functions as a suicide substrate inhibitor. Once bound to furin’s active site, α1-PDX/hf partitions with equal probability to undergo proteolysis by furin at the C-terminal side of the reactive center -Arg355-Ile-Pro-Arg358-↓ or to form a kinetically trapped SDS-stable complex with the enzyme. This partitioning between the complex-forming and proteolytic pathways contributes to the ability of α1-PDX/hf to differentially inhibit members of the proprotein convertase family. Finally, we propose a structural model of the α1-PDX-reactive site loop that explains the high degree of enzyme selectivity of this serpin and which can be used to generate small molecule furin inhibitors.

Impacts of coexisting bronchial asthma on severe exacerbations in mild-to-moderate COPD : results from a national database

Acknowledgments The authors would like to thank Kyungjoo Kim for the confident statistical analyses in this work. This study was supported by a grant (2014P3300300) from the Korea Centers for Disease Control and Prevention. The abstract of this paper was presented at the Asian Pacific Society of Respirology 20th Congress as an oral presentation with interim findings. The poster’s abstract was published in “Poster Abstracts” in Respirology