Thermoelectric cross-plane properties on p- and n-Ge/SixGe1-x superlattices

Silicon and germanium materials have demonstrated an increasing attraction for energy harvesting, due to their sustainability and integrability with complementary metal oxide semiconductor and micro-electro-mechanical-system technology. The thermoelectric efficiencies for these materials, however, are very poor at room temperature and so it is necessary to engineer them in order to compete with telluride based materials, which have demonstrated at room temperature the highest performances in literature [1]. Micro-fabricated devices consisting of mesa structures with integrated heaters, thermometers and Ohmic contacts were used to extract the cross-plane values of the Seebeck coefficient and the thermal conductivity from p- and n-Ge/SixGe1-x superlattices. A second device consisting in a modified circular transfer line method structure was used to extract the electrical conductivity of the materials. A range of p-Ge/Si0.5Ge0.5 superlattices with different doping levels was investigated in detail to determine the role of the doping density in dictating the thermoelectric properties. A second set of n-Ge/Si0.3Ge0.7 superlattices was fabricated to study the impact that quantum well thickness might have on the two thermoelectric figures of merit, and also to demonstrate a further reduction of the thermal conductivity by scattering phonons at different wavelengths. This technique has demonstrated to lower the thermal conductivity by a 25% by adding different barrier thicknesses per period

Electronic Event–based Surveillance for Monitoring Dengue, Latin America

Dengue, a potentially fatal disease, is spreading around the world. An estimated 2.5 billion people in tropical and subtropical regions are at risk. Early detection of outbreaks is crucial to prevention and control of dengue virus and other viruses. Case reporting may often take weeks or months. Therefore, researchers explored whether electronic sources of real-time information (such as Internet news outlets, health expert mailing lists, social media sites, and queries to online search engines) might be faster, and they were. Although information from unofficial sources should be interpreted with caution, when used in conjunction with traditional case reporting, real-time electronic surveillance can help public health authorities allocate resources in time to avert full-blown epidemics

Domain swapping between FEN-1 and XPG defines regions in XPG that mediate nucleotide excision repair activity and substrate specificity

FEN-1 and XPG are members of the FEN-1 family of structure-specific nucleases, which share a conserved active site. FEN-1 plays a central role in DNA replication, whereas XPG is involved in nucleotide excision repair (NER). Both FEN-1 and XPG are active on flap structures, but only XPG cleaves bubble substrates. The spacer region of XPG is dispensable for nuclease activity on flap substrates but is required for NER activity and for efficient processing of bubble substrates. Here, we inserted the spacer region of XPG between the nuclease domains of FEN-1 to test whether this domain would be sufficient to confer XPG-like substrate specificity and NER activity on a related nuclease. The resulting FEN-1-XPG hybrid protein is active on flap and, albeit at low levels, on bubble substrates. Like FEN-1, the activity of FEN-1-XPG was stimulated by a double-flap substrate containing a 1-nt 3′ flap, whereas XPG does not show this substrate preference. Although no NER activity was detected in vitro, the FEN-1-XPG hybrid displays substantial NER activity in vivo. Hence, insertion of the XPG spacer region into FEN-1 results in a hybrid protein with biochemical properties reminiscent of both nucleases, including partial NER activity

Geographical limits of the Southeastern distribution of Aedes aegypti (Diptera, Culicidae) in Argentina

The current geographical distribution of Aedes aegypti in South America is dramatically expanding inside Argentina, reaching a wider distribution than during its early eradication in 1967. Simultaneously, cases of dengue have increased during the last few years, and the situation has been recently worsened by the confirmation of the presence of the different dengue serotypes simultaneously circulating in new regions. Here we report on the passive south-eastern dispersion of A. aegypti in Argentina.Fil: Díaz Nieto, Leonardo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biociencias Agrícolas y Ambientales. Grupo Vinculado al Centro de Estudios de la Biodiversidad y Biotecnología de Mar del Plata- INBA. Fundación para Investigaciones Biológicas Aplicadas; ArgentinaFil: Maciá, Arnaldo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; ArgentinaFil: Perotti, M. Alejandra. University of Reading. School of Biological Sciences; Reino UnidoFil: Berón, Corina Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biociencias Agrícolas y Ambientales. Grupo Vinculado al Centro de Estudios de la Biodiversidad y Biotecnología de Mar del Plata- INBA. Fundación para Investigaciones Biológicas Aplicadas; Argentin

Characterization of a dengue type-specific epitope on dengue 3 virus envelope protein domain III

Dengue virus (DENV) is a mosquito-borne disease caused by four genetically and serologically related viruses termed DENV-1, -2, -3 and -4. The DENV envelope (E) protein ectodomain can be divided into three structural domains designated ED1, ED2 and ED3. The ED3 domain contains DENV type-specific and DENV complex-reactive antigenic sites. To date, nearly all antigenic studies on the E protein have focused on DENV-2. In this study, the epitope recognized by a DENV-3 type-specific monoclonal antibody (mAb 14A4-8) was mapped to the DENV-3 ED3 domain using a combination of physical and biological techniques. Epitope mapping revealed that amino acid residues V305, L306, K308, E309, V310, K325, A329, G381 and I387 were critical for the binding of mAb 14A4-8 and amino acid residues T303, K307, K386, W389 and R391 were peripheral residues for this epitope. The location of the mAb 14A4-8 epitope overlaps with the DENV complex-reactive antigenic site in the DENV-3 ED3 domain

The role of pathology in an investigation of an outbreak of West Nile encephalitis in New York, 1999.

An outbreak of encephalitis occurred in New York City in late August 1999, the first caused by West Nile virus in North America. Histopathologic and immunopathologic examinations performed on human autopsy materials helped guide subsequent laboratory and epidemiologic investigations that led to identification of the etiologic agent

Dengue reemergence in Argentina.

Aedes aegypti, eradicated from Argentina in 1963, has now reinfested the country as far south as Buenos Aires. In 1997, four persons with travel histories to Brazil, Ecuador, or Venezuela had confirmed dengue, and surveillance for indigenous transmission allowed the detection of 19 dengue cases in Salta Province. These cases of dengue are the first in Argentina since 1916 and represent a new southern extension of dengue virus

Analytic curves in algebraic varieties over number fields

We establish algebraicity criteria for formal germs of curves in algebraic varieties over number fields and apply them to derive a rationality criterion for formal germs of functions, which extends the classical rationality theorems of Borel-Dwork and P\'olya-Bertrandias valid over the projective line to arbitrary algebraic curves over a number field. The formulation and the proof of these criteria involve some basic notions in Arakelov geometry, combined with complex and rigid analytic geometry (notably, potential theory over complex and $p$-adic curves). We also discuss geometric analogues, pertaining to the algebraic geometry of projective surfaces, of these arithmetic criteria.Comment: 55 pages. To appear in "Algebra, Arithmetic, and Geometry: In Honor of Y.i. Manin", Y. Tschinkel & Yu. Manin editors, Birkh\"auser, 200