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One of the challenges for the realization of molecular electronics is the design of nanoscale molecular wires displaying long-range charge transport. Graphene nanoribbons are an attractive platform for the development of molecular wires with long-range conductance owing to their unique electrical properties. Despite their potential, the charge transport properties of single nanoribbons remain underexplored. Herein, we report a synthetic approach to prepare N-doped pyrene-pyrazinoquinoxaline molecular graphene nanoribbons terminated with diamino anchoring groups at each end. These terminal groups allow for the formation of stable molecular graphene nanoribbon junctions between two metal electrodes that were investigated by scanning tunneling microscope-based break-junction measurements. The experimental and computational results provide evidence of long-range tunneling charge transport in these systems characterized by a shallow conductance length dependence and electron tunneling through >6 nm molecular backbone.

There is increasing interest in the study of chiral degrees of freedom occurring in matter and in electromagnetic fields. Opportunities in quantum sciences will likely exploit two main areas that are the focus of this Review: (1) recent observations of the chiral-induced spin selectivity (CISS) effect in chiral molecules and engineered nanomaterials and (2) rapidly evolving nanophotonic strategies designed to amplify chiral light–matter interactions. On the one hand, the CISS effect underpins the observation that charge transport through nanoscopic chiral structures favors a particular electronic spin orientation, resulting in large room-temperature spin polarizations. Observations of the CISS effect suggest opportunities for spin control and for the design and fabrication of room-temperature quantum devices from the bottom up, with atomic-scale precision and molecular modularity. On the other hand, chiral–optical effects that depend on both spin- and orbital-angular momentum of photons could offer key advantages in all-optical and quantum information technologies. In particular, amplification of these chiral light–matter interactions using rationally designed plasmonic and dielectric nanomaterials provide approaches to manipulate light intensity, polarization, and phase in confined nanoscale geometries. Any technology that relies on optimal charge transport, or optical control and readout, including quantum devices for logic, sensing, and storage, may benefit from chiral quantum properties. These properties can be theoretically and experimentally investigated from a quantum information perspective, which has not yet been fully developed. There are uncharted implications for the quantum sciences once chiral couplings can be engineered to control the storage, transduction, and manipulation of quantum information. This forward-looking Review provides a survey of the experimental and theoretical fundamentals of chiral-influenced quantum effects and presents a vision for their possible future roles in enabling room-temperature quantum technologies.

In Spain, PCR is the tool of choice for the diagnosis of congenital Chagas disease (CD) and serology for diagnosing chronic CD. A loop-mediated isothermal amplification test for Trypanosoma cruziDNA detection showed good analytical performance and ease of use.

An enantiopure, conductive, and paramagnetic crystalline 3-D metal–organic framework (MOF), based on Dy(III) and the l-tartrate chiral ligand, is proved to behave as an almost ideal electron spin filtering material at room temperature, transmitting one spin component only, leading to a spin polarization (SP) power close to 100% in the ±2 V range, which is conserved over a long spatial range, larger than 1 μm in some cases. This impressive spin polarization capacity of this class of nanostructured materials is measured by means of magnetically polarized conductive atomic force microscopy and is attributed to the Chirality-Induced Spin Selectivity (CISS) effect of the material arising from a multidimensional helicity pattern, the inherited chirality of the organic motive, and the enhancing influence of Dy(III) ions on the CISS effect, with large spin–orbit coupling values. Our results represent the first example of a MOF-based and CISS-effect-mediated spin filtering material that shows a nearly perfect SP. These striking results obtained with our robust and easy-to-synthesize chiral MOFs constitute an important step forward in to improve the performance of spin filtering materials for spintronic device fabrication.

Theory suggests that many chemical reactions (not simply, as is often thought, redox reactions) might be catalysed by an applied electric field; experimental evidence for this is now provided from single-molecule studies of the formation of carbon–carbon bonds in a Diels–Alder reaction.

Amyloids are a family of self-aggregating proteins implicated in various central nervous system disorders, including Alzheimer’s disease (AD). It is thought that prefibrillar soluble forms of amyloid peptides, including oligomers, may be the main pathogenic factor in AD. Herein we describe the fabrication of well-defined, functionalized, monomeric β-amyloid peptide surfaces for studying protein−protein interactions. We first prepared a nonaggregating analogue of the β-amyloid peptide and then attached it to a gold surface covered with a self-assembled monolayer (SAM) of alkanethiols. After attachment, the native form of the β-amyloid peptide (Aβ40) was obtained by surface-level intramolecular O−N migration. The surface was characterized by atomic force microscopy (AFM) and self-assembled monolayer for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (SAMDI-TOF MS). The interaction between the surface-bound Aβ40 and monoclonal anti-Aβ40 antibody was tracked by AFM and chemiluminescence, which revealed that the Aβ40 was attached mainly in its monomeric form and that the protein−protein complex was assembled on the surface. Last, we used a proteomics approach to demonstrate the specificity of the Aβ40-functionalized surface in surface-binding experiments employing serum amyloid P (SAP) and bovine serum albumin (BSA).

We report on-off pointed MAMBO observations at 1.2 mm of 61 Spitzer-selected star-forming galaxies from the Spitzer Wide Area Infrared Extragalactic Legacy survey (SWIRE). The sources are selected on the basis of bright 24 mm fluxes (f 24 mm > 0.4 mJy) and of stellar dominated near-infrared spectral energy distributions in order to favor z [?] 2 starburst galaxies. The average 1.2 mm flux for the whole sample is 1.5 +- 0.2 mJy. Our analysis focuses on 29 sources in the Lockman Hole field where the average 1.2 mm flux (1.9 +- 0.3 mJy) is higher than in other fields (1.1 +- 0.2 mJy). The analysis of the multiwavelength spectral energy distributions indicates that these sources are starburst galaxies with far-infrared luminosities from 1012 to 1013.3 L , and stellar masses of [?]0.2-6 x 1011 M . Compared to submillimeter selected galaxies (SMGs), the SWIRE-MAMBO sources are among those with the largest 24 mm/1.2 mm flux ratios. The origin of such large ratios is investigated by comparing the average mid-infrared spectra and the stacked far-infrared spectral energy distributions of the SWIRE-MAMBO sources and of SMGs. The mid-infrared spectra, available for a handful of sources, exhibit strong polycyclic aromatic hydrocarbon (PAH) features, and a warm dust continuum. The warm dust continuum contributes [?]34% of the mid-infrared emission, and is likely associated with an AGN component. This contribution is consistent with what is found in SMGs. The large 24 mm/1.2 mm flux ratios are thus not due to AGN emission, but rather to enhanced PAH emission compared to SMGs. The analysis of the stacked far-infrared fluxes yields warmer dust temperatures than typically observed in SMGs. Our selection favors warm ultraluminous infrared sources at high-z, a class of objects that is rarely found in SMG samples. Indeed SMGs are not common among bright 24 mm sources (e.g., only about 20% of SMGs have f 24 mm > 0.4 mJy). Our sample is the largest Spitzer-selected sample detected at millimeter wavelengths currently available.

Hard X-ray surveys have uncovered a large population of heavily obscured AGNs. They also reveal a population of quasars with moderate obscuration at both visible and X-ray wavelengths. We use Chandra-selected samples of quasars from the ELAIS Deep X-ray Survey (EDXS) and the Chandra Deep Field-North to investigate the obscuration toward the nuclei of moderately obscured AGNs. We find an inverse correlation between the optical-to-X-ray flux ratio and the X-ray hardness ratio that can be interpreted as being due to obscuration at visible and X-ray wavelengths. We present detailed optical and near-infrared data for a sample of optically faint (R > 23) quasars from the EDXS. These are used to constrain the amount of rest-frame UV/optical reddening toward these quasars. It is found that optically faint quasars are mostly faint because of obscuration, not because they are intrinsically weak. After correcting for reddening, the optical magnitudes of most of these quasars are similar to the brighter quasars at these X-ray fluxes. Combining with gas column densities inferred from the X-ray observations, we consider the gas-to-dust ratios of the obscuring matter. We find that the quasars generally have higher gas-to-dust absorption than that seen in the Milky Way, similar to what has been found for nearby Seyfert galaxies. We consider the possible existence of a large population of X-ray sources that have optical properties of type 1 (unobscured) quasars but X-ray properties of type 2 (obscured) quasars. However, we find that such sources only contribute about 6% of the 0.5-8 keV X-ray background. Finally, we show that the observed distribution of optical-to-X-ray flux ratios of quasars at z > 1 is skewed to low values compared to the intrinsic distribution as a result of the fact that the observed-frame R-band light is emitted in the UV and is more easily obscured than hard X-rays.

The SIRTF Wide-Area Infrared Extragalactic Survey (SWIRE), the largest SIRTF Legacy program, is a wide-area imaging survey to trace the evolution of dusty, star-forming galaxies, evolved stellar populations, and active galactic nuclei (AGNs) as a function of environment, from redshifts z [?] 3 to the current epoch. SWIRE will survey seven high-latitude fields, totaling 60-65 deg2 in all seven SIRTF bands: Infrared Array Camera (IRAC) 3.6, 4.5, 5.6, and 8 um and Multiband Imaging Photometer for SIRTF (MIPS) 24, 70, and 160 um. Extensive modeling suggests that the Legacy Extragalactic Catalog may contain in excess of 2 million IR-selected galaxies, dominated by (1) [?]150,000 luminous infrared galaxies (LIRGs; LFIR > 1011 L[?]) detected by MIPS (and significantly more detected by IRAC), [?]7000 of these with z > 2; (2) 1 million IRAC-detected early-type galaxies ([?]2 x 105 with z > 1 and [?]10,000 with z > 2); and (3) [?]20,000 classical AGNs detected with MIPS, plus significantly more dust-obscured quasi-stellar objects/AGNs among the LIRGs. SWIRE will provide an unprecedented view of the evolution of galaxies, structure, and AGNs.The key scientific goals of SWIRE are (1) to determine the evolution of actively star forming and passively evolving galaxies in order to understand the history of galaxy formation in the context of cosmic structure formation; (2) to determine the evolution of the spatial distribution and clustering of evolved galaxies, starbursts, and AGNs in the key redshift range 0.5 < z < 3 over which much of cosmic evolution has occurred; and (3) to determine the evolutionary relationship between "normal galaxies" and AGNs and the contribution of AGN accretion energy versus stellar nucleosynthesis to the cosmic backgrounds. The large area of SWIRE is important to establish statistically significant population samples over enough volume cells that we can resolve the star formation history as a function of epoch and environment, i.e., in the context of structure formation. The large volume is also optimized for finding rare objects.The SWIRE fields are likely to become the next generation of large "cosmic windows" into the extragalactic sky. They have been uniquely selected to minimize Galactic cirrus emission over large scales. The Galaxy Evolution Explorer will observe them as part of its deep 100 deg2 survey, as will Herschel. SWIRE includes [?]9 deg2 of the unique large-area XMM Large Scale Structure hard X-ray imaging survey and is partly covered by the UKIDSS deep J and K survey. An extensive optical/near-IR imaging program is underway from the ground.The SWIRE data are nonproprietary; catalogs and images will be released twice yearly, beginning about 11 months after SIRTF launch. Details of the data products and release schedule are presented.