Nonclassicality Criteria in Multiport Interferometry.

Interference lies at the heart of the behavior of classical and quantum light. It is thus crucial to understand the boundaries between which interference patterns can be explained by a classical electromagnetic description of light and which, on the other hand, can only be understood with a proper quantum mechanical approach. While the case of two-mode interference has received a lot of attention, the multimode case has not yet been fully explored. Here we study a general scenario of intensity interferometry: we derive a bound on the average correlations between pairs of output intensities for the classical wavelike model of light, and we show how it can be violated in a quantum framework. As a consequence, this violation acts as a nonclassicality witness, able to detect the presence of sources with sub-Poissonian photon-number statistics. We also develop a criterion that can certify the impossibility of dividing a given interferometer into two independent subblocks.

Experimental realization of a one-way quantum computer algorithm solving Simon's problem.

We report an experimental demonstration of a one-way implementation of a quantum algorithm solving Simon's problem-a black-box period-finding problem that has an exponential gap between the classical and quantum runtime. Using an all-optical setup and modifying the bases of single-qubit measurements on a five-qubit cluster state, key representative functions of the logical two-qubit version's black box can be queried and solved. To the best of our knowledge, this work represents the first experimental realization of the quantum algorithm solving Simon's problem. The experimental results are in excellent agreement with the theoretical model, demonstrating the successful performance of the algorithm. With a view to scaling up to larger numbers of qubits, we analyze the resource requirements for an n-qubit version. This work helps highlight how one-way quantum computing provides a practical route to experimentally investigating the quantum-classical gap in the query complexity model.

Mimicking the probability distribution of a two-dimensional Grover walk with a single-qubit coin.

The nonlocalized case of the spatial density probability of the two-dimensional Grover walk can be obtained using only a two-dimensional coin space and a quantum walk in alternate directions. This significantly reduces the resources necessary for its feasible experimental realization. We present a formal proof of this correspondence and analyze the behavior of the coin-position entanglement as well as the x-y spatial entanglement in our scheme with respect to the Grover one. Our scheme allows us to entangle the two orthogonal directions of the walk more efficiently.

Penile cancer: prognostic and predictive factors in clinical decision-making.

Penile cancer (PC) is a typical tumor of non-industrialized countries. The incidence is 20-30 times higher in Africa and South America, considering the elevated prevalence of sexually transmitted diseases. Histologically, PC includes squamous cell carcinoma (SCPC), the most frequent, and nonsquamous carcinoma (NSCPC). Early diagnosis is the goal, whereas later diagnosis relates to poor functional outcomes and worse prognosis. The 5-year survival rate is 85% for patients with histologically regional negative lymph nodes, compared to 29%-40% for those with histologically regional positive lymph nodes. To date no new drugs are approved, and there are few new data about molecular mechanisms underlying tumorigenesis. The SCPC remains a rare tumor and the current therapeutic algorithm is based principally on retrospective analysis and less on prospective trials. In this review article, biomarkers of prognosis and efficacy of current treatments are summarized with a focus on those that have the potential to affect treatment decision-making in SCPC.

Hydrogels for biomedical applications from glycol chitosan and PEG diglycidyl ether exhibit pro-angiogenic and antibacterial activity.

We aimed at producing a hydrogel from a chitosan (CS) derivative soluble in physiological conditions to avoid any purification step thus allowing to use the materials also as an in-situ forming material. So, we crosslinked glycol chitosan (GCS) with poly(ethylene glycol) diglycidyl ether (PEGDE) in water at 37 °C. The scaffolds, referred as GCS-PEG, were specifically designed to be used as wound dressing materials as such (after crosslinking) or as in-situ forming materials. Different amounts of PEGDE were tested. The obtained scaffolds showed macroscopic pores and a tailorable swelling in water by controlling the crosslinking degree. Moreover, GCS-PEG scaffolds displayed a significant antimicrobial activity against Staphylococcus aureus. In-vivo study using the chick embryo choriallantoic membrane resulted in a highly pronounced pro-angiogenic activity suggesting important tissue regeneration properties. Moreover, the employed materials are commercially available, no organic solvents are required and the scaling up is quite predictable.

Quantum cascade laser-based photoacoustic spectroscopy of volatile chemicals: application to hexamethyldisilazane.

The use of photoacoustic spectroscopy and mid-infrared quantum-cascade lasers (QCLs) for the detection of hexamethyldisilazane (HMDS) is reported. A detection limit of 200 parts in 10(9) is found using a Fabry-Perot QCL operated at 8.4 microm in pulsed mode and a photoacoustic cell equipped with four electret microphones. The laser multimode spectrum matches the range of the N-H bending absorption band of HMDS. Further improvements to reach lower detection limits are discussed.

Two-walker discrete-time quantum walks on the line with percolation.

One goal in the quantum-walk research is the exploitation of the intrinsic quantum nature of multiple walkers, in order to achieve the full computational power of the model. Here we study the behaviour of two non-interacting particles performing a quantum walk on the line when the possibility of lattice imperfections, in the form of missing links, is considered. We investigate two regimes, statical and dynamical percolation, that correspond to different time scales for the imperfections evolution with respect to the quantum-walk one. By studying the qualitative behaviour of three two-particle quantities for different probabilities of having missing bonds, we argue that the chosen symmetry under particle-exchange of the input state strongly affects the output of the walk, even in noisy and highly non-ideal regimes. We provide evidence against the possibility of gathering information about the walkers indistinguishability from the observation of bunching phenomena in the output distribution, in all those situations that require a comparison between averaged quantities. Although the spread of the walk is not substantially changed by the addition of a second particle, we show that the presence of multiple walkers can be beneficial for a procedure to estimate the probability of having a broken link.

UV crosslinked poly(acrylic acid): a simple method to bio-functionalize electrolyte-gated OFET biosensors.

A simple and time-saving wet method to endow the surface of organic semiconductor films with carboxyl functional groups is presented. A thin layer of poly(acrylic acid) (pAA) is spin-coated directly on the electronic channel of an electrolyte-gated organic FET (EGOFET) device and cross-linked by UV exposure without the need for any photo-initiator. The carboxyl functionalities are used to anchor phospholipid bilayers through the reaction with the amino-groups of phosphatidyl-ethanolamine (PE). By loading the membranes with phospholipids carrying specific functionalities, such a platform can be easily implemented with recognition elements. Here the case of biotinylated phospholipids that allow selective streptavidin electronic detection is described. The surface morphology and chemical composition are monitored using SEM and XPS, respectively, during the whole process of bio-functionalization. The electronic and sensing performance level of the EGOFET biosensing platform is also evaluated. Selective analyte (streptavidin) detection in the low pM range is achieved, this being orders of magnitude lower than the performance level obtained by the well assessed surface plasmon resonance assay reaching the nM level, at most.

Hamiltonian tomography in an access-limited setting without state initialization.

We propose a scheme for the determination of the coupling parameters in a chain of interacting spins. This requires only time-resolved measurements over a single particle, simple data postprocessing and no state initialization or prior knowledge of the state of the chain. The protocol fits well into the context of quantum-dynamics characterization and is efficient even when the spin chain is affected by general dissipative and dephasing channels. We illustrate the performance of the scheme by analyzing explicit examples and discuss possible extensions.

Perfect state transfer on a spin chain without state initialization.

We demonstrate that perfect state transfer can be achieved using an engineered spin chain and clean local end-chain operations, without requiring the initialization of the state of the medium nor fine-tuning of control pulses. This considerably relaxes the prerequisites for obtaining reliable transfer of quantum information across interacting-spin systems. Moreover, it allows us to shed light on the interplay among purity, entanglement, and operations on a class of many-body systems potentially useful for quantum information processing tasks.

Genetics of aneuoploidy in man reconsidered by banding studies.

The effects of aneuploidy are only partially known in man, but the information available suggests that they are remarkably similar to those in Drosophila melanogaster. The fractions of the haploid genome that can be tolerated in three doses and in one dose approach 7 and 3%, respectively. Hypoploidy is more deleterious than hyperploidy. The phenotypic effects of aneuploidy result in an 'aneuploid syndrome' of developmental, mental and growth retardation and multiple malformations. Even if upon closer scrutiny a recognizable collection of dysmorphisms can be detected in some chromosomal imbalances, specific phenotypes result only as the consequence of changes in dosage-sensitive loci. The aneuploidy of man was approached by chromosomal band studies. Available data suggest that R bands may be rich in functional DNA. The proportion of R bands involved in viable imbalances was calculated, and it is concluded that nearly all chromosomal arms tolerate trisomies or monosomies of a proportion of their R band content. This evidence and the demonstration of the involvement of proportionally similar quantities of band type in viable aneuploidies contrast with the idea that imbalances with a higher R band proportion have less chances of survival. Thus band patterns seem to be adequate to provide empirical clinical phenotypes but inadequate to reflect the genetic make-up of a given chromosome.

Genomic distribution of transposable elements among individuals of an inbred Drosophila line.

The stability of the elements of eleven transposon families (412, B 104, blood, 297, 1731, G, copia, mdg 4, hobo, jockey and I) has been compared by the Southern technique among individuals of a Drosophila line that has been subjected to 30 generations of sister sib matings. The 412, B104, blood, 297, 1731 and G elements appear stable. Heterochromatic copia and hobo elements and euchromatic I elements appear highly polymorphic. In addition, copia, mdg 4, jockey and I elements undergo an instability resulting in significant variations in relative intensity among autoradiographic bands. The extent of the polymorphisms detected strongly suggests de novo rearrangements of transposable elements.

Evidence for a host role in regulating the activity of transposable elements in Drosophila melanogaster: the case of the persistent instability of Bari 1 elements in Charolles stock.

In most reports in which the activity of numerous Drosophila transposon families has been studied, only a subset of the families tested appears mobile. A comparison of these data shows that there are no transposons inherently more unstable than others and suggests that host factors regulate the activity of transposable elements. Consistent with this conclusion are the properties of Bari 1 elements, which are the only ones of the 14 families tested to be unstable in Charolles stock. Instability is persistent over 53 generations and appears to affect recurrent insertion sites.

Intragenomic distribution and stability of transposable elements in euchromatin and heterochromatin of Drosophila melanogaster: elements with inverted repeats Bari 1, hobo, and pogo.

The elements of the Bari 1, hobo, and pogo transposon families that are located in euchromatin, heterochromatin, and on the Y chromosome have been identified, and their stability has been assessed by Southern blot analysis. The fraction of heterochromatic elements appears to be distinctive of all transposon families tested, except for Bari 1. Evidence for instability of heterochromatic elements is described. The analysis of unstable elements in different Drosophila stocks suggests that the host genome contributes to the stability/instability of transposon families.

Molecular analysis of two rolling-circle replicating cryptic plasmids, pBMYdx and pBMY1, from the soil gram-positive Bacillus mycoides.

Two cryptic plasmids of two environmental strains of the soil Bacillus mycoides were cloned and sequenced. They are of a small size (3377 and 3476 bp) and carry regions homologous to double- and single-strand origins of replication of rolling-circle replication modules. In addition, both plasmids have ORFs with homologies with Mob and Rep proteins, in the same relative position and orientation. While dso- and sso-like sequences are similar in pBMY1 and pBMYdx, the putative Mob and Rep proteins are not homologous between the two but show similarity with Mob and Rep proteins of different bacterial plasmids.

Evidence for de novo rearrangements of Drosophila transposable elements induced by the passage to the cell culture.

The genomic distribution and the number of elements of eleven transposon families have been compared by the Southern technique between permanent cultured cells, larval salivary glands and the brains and whole flies of an inbred Drosophila line (inb-c) from which the cells were established. In cultured cells, changes in restriction patterns consistent with various types of rearrangements such as amplification, transposition and excision of the elements of copia, 1731, 412, 297 and mdg-4 transposon families are detected whereas B 104, G and blood elements appear stable. In previous reports these rearrangements were not detected among individuals of the inb-c line or among samples of somatic tissues, or in samples spanning years of maintenance of cultured cells. Hence, we believe that they have been induced de novo during the passage to the cell culture.

Potentially active copies of the gypsy retroelement are confined to the Y chromosome of some strains of Drosophila melanogaster possibly as the result of the female-specific effect of the flamenco gene.

Gypsy is an endogenous retrovirus present in the genome of Drosophila melanogaster. This element is mobilized only in the progeny of females which contain active gypsy elements and which are homozygous for permissive alleles of a host gene called flamenco (flam). Some data strongly suggest that gypsy elements bearing a diagnostic HindIII site in the central region of the retrovirus body represent a subfamily that appears to be much more active than elements devoid of this site. We have taken advantage of this structural difference to assess by the Southern blotting technique the genomic distribution of active gypsy elements. In some of the laboratory Drosophila stocks tested, active gypsy elements were found to be restricted to the Y chromosome. Further analyses of 14 strains tested for the permissive vs. restrictive status of their flamenco alleles suggest that the presence of permissive alleles of flam in a stock tends to be associated with the confinement of active gypsy elements to the Y chromosome. This might be the result of the female-specific effect of flamenco on gypsy activity.

Accumulation of transposable elements in the heterochromatin and on the Y chromosome of Drosophila simulans and Drosophila melanogaster.

The elements of the transposon families G, copia, mdg 1, 412, and gypsy that are located in the heterochromatin and on the Y chromosome have been identified by the Southern blotting technique in Drosophila simulans and D. melanogaster populations. Within species, the abundance of such elements differs between transposon families. Between species, the abundance in the heterochromatin and on the Y chromosome of the elements of the same family can differ greatly suggesting that differences within a species are unrelated to structural features of elements. By shedding some new light on the mechanism of accumulation of transposable elements in the heterochromatin, these data appear relevant to the understanding of the long-term interaction between transposable elements and the host genome.

On the transposition of copia-like nomadic elements in cultured Drosophila cells.

We studied the stability of the genomic distribution of six retrotransposon families in long-term and short-term cultures of Drosophila cells. In a subclone derived from Kc cells, no significant rearrangements were detected over an 8 year period. On the contrary, extensive reshuffling and amplification of transposon families were observed in recently established cell lines. These results show that in cultured Drosophila cells transposition appears to be restricted to the transition from the embryo to continuous cell lines.

Genomic distribution of copia-like transposable elements in somatic tissues and during development of Drosophila melanogaster.

The genomic distribution of elements of the copia, 412, B 104, mdg 1, mdg 4 and 1731 transposon families was compared by the Southern technique in DNA preparations extracted from brains, salivary glands and adult flies of two related Drosophila lines. The copia, 412 and mdg 1 sequences were also probed in DNA from sperm, embryos, and 1st and 2nd instar larvae. The homogeneity of the patterns observed shows that somatic transposition is unlikely to occur frequently. A correlation between mobility and the euchromatic or heterochromatic location of transposable elements is discussed. In addition, an explanation of the variable band intensities of transposable elements in Southern autoradiographs is proposed.