Line-Shaped Illumination: A Promising Configuration for a Flexible Two-Photon Microscopy Setup

An innovative two-photon microscope exploiting a line-shaped illumination has been recently devised and then implemented. Such configuration allows to carry out a real-time detection by means of standard CCD cameras and is able to maintain the same resolution as commonly used point-scanning devices, thus overcoming what is usually regarded as the main limitation of linescanning microscopes. Here, we provide an overview of the applications in which this device has been tested and has proved to be a flexible and efficient tool, namely imaging of biological samples, in-depth sample reconstruction, two-photon spectra detection, and dye cross-section measurements. These results demonstrate that the considered setup is promising for future developments in many areas of research and applications

Experimental evidence of delocalized states in random dimer superlattices

We study the electronic properties of GaAs-AlGaAs superlattices with intentional correlated disorder by means of photoluminescence and vertical dc resistance. The results are compared to those obtained in ordered and uncorrelated disordered superlattices. We report the first experimental evidence that spatial correlations inhibit localization of states in disordered low-dimensional systems, as our previous theoretical calculations suggested, in contrast to the earlier belief that all eigenstates are localized.Comment: 4 pages, 5 figures. Physical Review Letters (in press

Observation of electro-activated localized structures in broad area VCSELs

We demonstrate experimentally the electro-activation of a localized optical structure in a coherently driven broad-area vertical-cavity surface-emitting laser (VCSEL) operated below threshold. Control is achieved by electro-optically steering a writing beam through a pre-programmable switch based on a photorefractive funnel waveguide.Comment: 5 Figure

Novel insights into the transport mechanism of the human amino acid transporter LAT1 (SLC7A5) : probing critical residues for substrate translocation

BACKGROUND: LAT1 (SLC7A5) is the transport competent unit of the heterodimer formed with the glycoprotein CD98 (SLC3A2). It catalyzes antiport of His and some neutral amino acids such as Ile, Leu, Val, Cys, Met, Gln and Phe thus being involved in amino acid metabolism. Interestingly, LAT1 is over-expressed in many human cancers that are characterized by increased demand of amino acids. Therefore LAT1 was recently acknowledged as a novel target for cancer therapy. However, knowledge on molecular mechanism of LAT1 transport is still scarce. METHODS: Combined approaches of bioinformatics, site-directed mutagenesis, chemical modification, and transport assay in proteoliposomes, have been adopted to unravel dark sides of human LAT1 structure/function relationships. RESULTS: It has been demonstrated that residues F252, S342, C335 are crucial for substrate recognition and C407 plays a minor role. C335 and C407 cannot be targeted by SH reagents. The transporter has a preferential dimeric structure and catalyzes an antiport reaction which follows a simultaneous random mechanism. CONCLUSIONS: Critical residues of the substrate binding site of LAT1 have been probed. This site is not freely accessible by molecules other than substrate. Similarly to LeuT, K+ has some regulatory properties on LAT1. GENERAL SIGNIFICANCE: The collected data represent a solid basis for deciphering molecular mechanism underlying LAT1 function

What if? Mouse proteomics after gene inactivation

The complex interactions among proteins and of proteins with small molecular weight protein ligands are overturned every time one of the components of the network is missing. For study purposes, animal models lacking one protein are obtained by experimental manipulation of the genome: in the knocking out approach, a gene is altered through the insertion of an artificial DNA sequence, which halts the transcription-translation sequence of events. In this review we have compiled the research papers that analyze the effects of knocking out individual genes on the proteomes of various tissues/organs throughout the body. We have gathered and organized all the available evidence and then compared the proteomic data in order to stress the context-specificity of the outcome every time two or more organs were investigated in the same KO mice. Finally, in a symmetrical approach to the above, we surveyed whether there is any obvious overlap among the effects of different KO on the same organ, marking affection of general pathways or lacking specificity of the gene targeting. Specific attention was put on the possible involvement of cellular stress markers

Electronic structure and vertical transport in random dimer GaAs-Al_xGa_(1-x)As superlattices

We report a systematic study of several GaAs-AlxGa1-xAs semiconductor superlattices grown by molecular-beam epitaxy specifically designed to explore the existence of extended states in random dimer superlattices. We have confirmed our previous results [V. Bellani et al., Phys. Rev. Lett. 82, 2159 (1999)] with much additional evidence that allows us to lay claim to a clear-cut experimental verification of the presence of extended states in random dimer superlattices due to the short-range correlations (dimers) that inhibit the localization effects of the disorder

Lax-Phillips Scattering Theory of a Relativistic Quantum Field Theoretical Lee-Friedrichs Model and Lee-Oehme-Yang-Wu Phenomenology

The one-channel Wigner-Weisskopf survival amplitude may be dominated by exponential type decay in pole approximation at times not too short or too long, but, in the two channel case, for example, the pole residues are not orthogonal, and the pole approximation evolution does not correspond to a semigroup (experiments on the decay of the neutral K-meson system support the semigroup evolution postulated by Lee, Oehme and Yang, and Yang and Wu, to very high accuracy). The scattering theory of Lax and Phillips, originally developed for classical wave equations, has been recently extended to the description of the evolution of resonant states in the framework of quantum theory. The resulting evolution law of the unstable system is that of a semigroup, and the resonant state is a well-defined funtion in the Lax-Phillips Hilbert space. In this paper we apply this theory to relativistically covarant quantum field theoretical form of the (soluble) Lee model. We show that this theory provides a rigorous underlying basis for the Lee-Oehme-Yang-Wu construction.Comment: Plain TeX, 34 page

Report of 4 Cases and Review of the Literature

We reviewed the clinical, microbiologic, and outcome characteristics of 72 patients with human immunodeficiency virus (HIV)-associated histoplasmosis (4 newly described) reported in Europe over 20 years (1984-2004). Seven cases (9.7%) were acquired in Europe (autochthonous), whereas the majority involved a history of travel or arrival from endemic areas. The diagnosis of progressive disseminated histoplasmosis (PDH) was made during life in 63 patients (87.5%) and was the acquired immunodeficiency syndrome (AIDS)-presenting illness in 44 (61.1%). Disease was widespread in 66 patients (91.7%) and localized in 6 (8.3%), with the skin being the most frequent site of localized infection. Overall skin involvement was reported in 47.2% of the patients regardless of whether histoplasmosis was acquired in Africa or South America. Reticulonodular or diffuse interstial infiltrates occurred in 52.8%. The diagnosis was made during life by histopathology plus culture in 44 patients (69.8%), histopathology alone in 18 (28.5%), and culture alone in 1 (1.5%). During the induction phase amphotericin B and itraconazole (74.6%) were the single most frequently used drugs. Both drugs were also used either in combination (10.2%) or in sequential therapy (11.8%). Cumulative mortality rate during the induction phase of treatment was 15.2%. Overall, 37 patients died (57.8%); death occurred early in the course in 18 (28.1%). Seven of 40 patients (17.5%) who responded to therapy subsequently relapsed. Autopsy data in 13 patients confirmed the widespread disseminated nature of histoplasmosis (85%) among AIDS patients with a median of 4.5 organs involved. The results of the present report highlight the need to consider the diagnosis of PDH among patients with AIDS in Europe presenting with a febrile illness who have traveled to or who originated from an endemic area

With or without you - Proteomics with or without major plasma/serum proteins

The first sections of this review compile and discuss strategies and protocols for managing plasma/serum as a source of biomarkers relevant to human disease. In many such cases, depletion of abundant protein(s) is a crucial preliminary step to the procedure; specific conceptual and technical approaches, however, make it possible to effectively use to this purpose whole plasma/serum. The final sections focus instead on the complexity associated with each of the major serum/plasma proteins in terms of both, multiple molecular structures (existence of a number of protein species) and of multiple molecular functions (behavior as multifunctional/multitasking/moonlighting proteins). Reviewing evidence in these and some related fields (regulation of the synthetic pattern by proteins and non-protein compounds and its connection with health and disease) prompts the suggestion/recommendation that information on the abundant components of plasma/serum proteome is routinely obtained and processed/mined as a valuable contribution to the characterization of any non-physiological condition and to the understanding of its mechanisms and of its implications/sequels