Plasmonic light trapping leads to responsivity increase in colloidal quantum dot photodetectors

We report broadband responsivity enhancement in PbS colloidal quantum dot (CQDs) photoconductive photodetectors due to absorption increase offered by a plasmonic scattering layer of Ag metal nanoparticles. Responsivity enhancements are observed in the near infrared with a maximum 2.4-fold increase near the absorption band edge of 1 lm for 400 nm thick devices. Additionally, we study the effect of the mode structure on the efficiency of light trapping provided by random nanoparticle scattering in CQD films and provide insights for plasmonic scattering enhancement in CQD thin films.This research has been partially supported by Fundacio´ Privada Cellex Barcelona. We also acknowledge support from European Commission’s Seventh Framework Programme for Research under contract PIRG06-GA-2009-256355

Differential elastic electron scattering cross sections for CCl₄ by 1.5–100 eV energy electron impact

We report absolute elastic differential, integral and momentum transfer cross sections for electron interactions with CCl₄. The incident electron energy range is 1.5-100 eV, and the scattered electron angular range for the differential measurements varies from 15°-130°. The absolute scale of the differential cross section was set using the relative flow technique with helium as the reference species. Comparison with previous total cross sections shows good agreement. Atomic-like behaviour in this scattering system is shown here for the first time, and is further investigated by comparing the CCl₄ elastic cross sections to recent results on the halomethanes and atomic chlorine at higher impact energies [H. Kato, T. Asahina, H. Masui, M. Hoshino, H. Tanaka, H. Cho, O. Ingólfsson, F. Blanco, G. Garcia, S. J. Buckman, and M. J. Brunger, J. Chem. Phys. 132, 074309 (2010)].This work was conducted under the support of the Japanese Ministry of Education, Sport, Culture and Technology. H.K. acknowledges the Japan Society for the Promotion of Science (JSPS) for his fellowships as grants-in-aid for scientific research. S.J.B also acknowledges the JSPS Invitation Fellowship for Research in Japan

Actividad molusquicida de extractos acuosos vegetales sobre el caracol manzana pomacea canaliculata

En el Ecuador, entre el 40 y 48% de la producción de arroz se pierde a causa del ataque de Pomacea canaliculata, una de las cien especies invasivas más dañinas del mundo que actualmente ha infestado alrededor de 170.000 hectáreas del cultivo en todo el territorio nacional

Ferromagnetism in bulk Co-Zn-O

The origin of ferromagnetism in diluted magnetic semiconductors is still an open question, yielding a great deal of research across the world. This work focuses on the Co-Zn-O system. Room-temperature ferromagnetism is observed after a partial reaction of Co_3O_4 and ZnO, which can be ascribed neither to carrier mediation nor segregated cobalt metallic clusters. Another mechanism is yielding room-temperature ferromagnetism. This mechanism is associated with a partial reaction of ZnO and Co_3O_4 grains, and always appears when the starting phases (Co_3O_4 and ZnO) are present in the sample, suggesting that interfaces are involved in the origin of the observed ferromagnetism

Topoisomerase II inhibitors induce DNA damage-dependent interferon responses circumventing Ebola virus immune evasion

Ebola virus (EBOV) protein VP35 inhibits production of interferon alpha/beta (IFN) by blocking RIG-I-like receptor signaling pathways, thereby promoting virus replication and pathogenesis. A high-throughput screening assay, developed to identify compounds that either inhibit or bypass VP35 IFN-antagonist function, identified five DNA intercalators as reproducible hits from a library of bioactive compounds. Four, including doxorubicin and daunorubicin, are anthracycline antibiotics that inhibit topoisomerase II and are used clinically as chemotherapeutic drugs. These compounds were demonstrated to induce IFN responses in an ATM kinase-dependent manner and to also trigger the DNA-sensing cGAS-STING pathway of IFN induction. These compounds also suppress EBOV replication in vitro and induce IFN in the presence of IFN-antagonist proteins from multiple negative-sense RNA viruses. These findings provide new insights into signaling pathways activated by important chemotherapy drugs and identify a novel therapeutic approach for IFN induction that may be exploited to inhibit RNA virus replication

A comprehensive and comparative study of elastic electron scattering from OCS and CS2 in the energy region from 1.2 to 200 eV

We report absolute differential cross sections (DCSs) for elastic electron scattering from OCS (carbonyl sulphide) and CS₂ (carbon disulphide) in the impact energy range of 1.2-200 eV and for scattering angles from 10° to 150°. Above 10 eV, the angular distributions are found to agree quite well with our present calculations using two semi-phenomenological theoretical approaches. One employs the independent-atom model with the screening-corrected additivity rule (IAM-SCAR), while the other uses the continuum-multiple-scattering method in conjunction with a parameter-free exchange-polarization approximation. Since OCS is a polar molecule, further dipole-induced rotational excitation cross sections have been calculated in the framework of the first Born approximation and incoherently added to the IAM-SCAR results. In comparison with the calculated DCS for the S atom, atomic-like behavior for the angular distributions in both the OCS and CS₂ scattering systems is observed. Integrated elastic cross sections are obtained by extrapolating the experimental measurements, with the aid of the theoretical calculations, for those scattering angles below 10° and above 150°. These values are then compared with the available total cross sections.The present work has been supported by the Japanese Ministry of Education, Sport, Culture and Technology and the Australian Research Council through its Centers of Excellence program. PL-V acknowledges his Visiting Professor position at Sophia University, Tokyo, Japan and also the Portuguese PEst-OE/FIS/UI0068/2011 grant. This work forms part of the EU/ESF COST Action CM0805 programme “The Chemical Cosmos.” M.J.B. and S.J.B. acknowledge the JSPS for provision of a Senior Fellowship, and the University of Malaya for their hospitality as Visiting Professor F. Blanco and Professor G. García acknowledge partial financial support of the Spanish Ministerio de Economia y Competitividad through Project No. FIS2009-10245 as well as the EU/ESF COST Action MP1002

A Primer on Resonances in Quantum Mechanics

After a pedagogical introduction to the concept of resonance in classical and quantum mechanics, some interesting applications are discussed. The subject includes resonances occurring as one of the effects of radiative reaction, the resonances involved in the refraction of electromagnetic waves by a medium with a complex refractive index, and quantum decaying systems described in terms of resonant states of the energy. Some useful mathematical approaches like the Fourier transform, the complex scaling method and the Darboux transformation are also reviewed.Comment: 28 pages, 9 figures, lectures presented at the Advanced Summer School in Physics 2008, Cinvestav, Mexic