Degradability of Bosonic Gaussian channels

The notion of weak-degradability of quantum channels is introduced by generalizing the degradability definition given by Devetak and Shor. Exploiting the unitary equivalence with beam-splitter/amplifier channels we then prove that a large class of one-mode Bosonic Gaussian channels are either weakly degradable or anti-degradable. In the latter case this implies that their quantum capacity Q is null. In the former case instead, this allows us to establish the additivity of the coherent information for those maps which admit unitary representation with single-mode pure environment.Comment: 7 pages, 1 figure, 1 table (minor editing

Lactate dehydrogenase A inhibition by small molecular entities: steps in the right direction

Direct targeting of energy metabolism to defeat cancer is not a recent strategy. Although quite a few drugs use cellular metabolism for their antitumor effect, no direct inhibitors of energy metabolism have been approved by the FDA. Currently, several inhibitors of lactate dehydrogenase A (LDH-A), a key player in glycolysis, are in development. Earlier, we demonstrated the efficacy of N-hydroxyindole-based LDH-A inhibitors in different cancer types. In this study we describe the efficacy of NHI-Glc-2, which is designed to dual target cancer cells, by exploiting a simultaneous enhanced glucose uptake by overexpressed glucose transporter 1 (GLUT1) and by inhibition of LDH-A. NHI-Glc-2 inhibits LDH-A enzyme activity, PANC-1 cell growth and disrupts spheroid integrity, with an overall effect that is more pronounced when combined with gemcitabine

Teleportation-Induced Correlated Quantum Channels

Quantum teleportation of a n-qubit state performed using as entangled resource a general bipartite state of 2n qubits instead of n Bell states is equivalent to a correlated Pauli channel. This provides a new characterization of such channels in terms of many-body correlation functions of the teleporting media. Our model is then generalized to the Continuous Variable case. We show that this new representation provides a relatively simple method for determining whether a correlated quantum channel is able to reliably convey quantum messages by studying the entanglement properties of the teleportation mediating system.Comment: 4 pages, 2 figure

Lung ultrasound in systemic sclerosis: correlation with high-resolution computed tomography, pulmonary function tests and clinical variables of disease

Interstitial lung disease (ILD) is a hallmark of systemic sclerosis (SSc). Although high-resolution computed tomography (HRCT) is the gold standard to diagnose ILD, recently lung ultrasound (LUS) has emerged in SSc patients as a new promising technique for the ILD evaluation, noninvasive and radiation-free. The aim of this study was to evaluate if there is a correlation between LUS, chest HRCT, pulmonary function tests findings and clinical variables of the disease. Thirty-nine patients (33 women and 6 men; mean age 51 ± 15.2 years) underwent clinical examination, HRCT, pulmonary function tests and LUS for detection of B-lines. A positive correlation exists between the number of B-lines and the HRCT score (r = 0.81, p < 0.0001), conversely a negative correlation exists between the number of B-lines and diffusing capacity of the lung for carbon monoxide (DLCO) (r = −0.63, p < 0.0001). The number of B-lines increases along with the progression of the capillaroscopic damage. A statistically significant difference in the number of B-lines was found between patients with and without digital ulcers [42 (3–84) vs 16 (4–55)]. We found that the number of B-lines increased with the progression of both HRCT score and digital vascular damage. LUS may therefore, be a useful tool to determine the best timing for HRCT execution, thus, preventing for many patients a continuous and useless exposure to ionizing radiatio

Qubit channels with small correlations

We introduce a class of quantum channels with correlations acting on pairs of qubits, where the correlation takes the form of a shift operator onto a maximally entangled state. We optimise the output purity and show that below a certain threshold the optimum is achieved by partially entangled states whose degree of entanglement increases monotonically with the correlation parameter. Above this threshold, the optimum is achieved by the maximally entangled state characterizing the shift. Although, a full analysis can only be done for the 2-norm, both numerical and heuristic arguments indicate that this behavior and the optimal inputs are independent of p>1 when the optimal output purity is measured using the p-norm.Comment: 11 pages, 4 figures, 2 table

The optimal unitary dilation for bosonic Gaussian channels

A generic quantum channel can be represented in terms of a unitary interaction between the information-carrying system and a noisy environment. Here, the minimal number of quantum Gaussian environmental modes required to provide a unitary dilation of a multi-mode bosonic Gaussian channel is analyzed both for mixed and pure environment corresponding to the Stinespring representation. In particular, for the case of pure environment we compute this quantity and present an explicit unitary dilation for arbitrary bosonic Gaussian channel. These results considerably simplify the characterization of these continuous-variable maps and can be applied to address some open issues concerning the transmission of information encoded in bosonic systems.Comment: 9 page

Qubit quantum channels: A characteristic function approach

A characterization of qubit quantum channels is introduced. In analogy to what happens in the context of Bosonic channels we exploit the possibility of representing the states of the system in terms of characteristic function. The latter are functions of non-commuting variables (Grassmann variables) and are defined in terms of generalized displacement operators. In this context we introduce the set of Gaussian channels and show that they share similar properties with the corresponding Bosonic counterpart.Comment: 10 pages (minor editing

A new approach to characterize qubit channels

We analyze qubit channels by exploiting the possibility of representing two-level quantum systems in terms of characteristic functions. To do so, we use functions of non-commuting variables (Grassmann variables), defined in terms of generalized displacement operators, following an approach which resemble the one adopted for continuous-variable (Bosonic) systems. It allows us to introduce the notion of qubit Gaussian channels and to show that they share similar properties with the corresponding continuous-variable counterpart. Some examples of qubit channels are investigated using this approach.Comment: 6 pages, accepted for publication in the special issue of IJQI "Noise, Information and Complexity at Quantum Scale", eds. S. Mancini and F. Marchesoni (2008

Dopaminergic system is differently altered in hippocampus and facial nucleus of trimethyltin rat model

Trimethyltin (TMT) is an organotin compound which is considered a useful tool to obtain an animal model of neurodegeneration associated with cognitive impairment (Pompili et al., 2011; Geloso et al., 2011). In the present work, this model was used in order to investigate the animal behaviour in association with the immunohistochemical expression of dopaminergic system (D1- and D2-like receptors and dopamine transporters DAT, VMAT-1 and -2) and cells viability (NEU-N) in the rat hippocampus and facial nucleus regions. TMT-treated group showed impaired spatial reference memory in a Morris water maze task compared to control group whereas the memory consolidation tested 24h after was preserved. In the open field, TMT-treated rats showed a decreased in time spent in rearing episodes reflecting a lower interest to explore a novel environment. In the hippocampal area of TMT-treated group, cell viability was significantly reduced by 45.9% whereas the D1, D2, DAT and VMAT- 2 receptor proteins immunoreactivity was significantly decreased by 57.5, 72.8, 64.1, 72.1%. In the facial nucleus, immunoreactivity reduction was observed only for dopamine transporters (average: 60% about) while the NEU-N reduction was 40%. These data were confirmed by real time RT-PCR analysis. These results suggest a differential involvement of the D1-type and D2-type receptors in the regulation of learning and memory. Besides, alterations on the functional ratio of DAT to VMAT-2 could predispose the cells to injury even at very low doses of TMT. The data obtained in facial nucleus demonstrate a different sensibility to xenobiotic of dopamine receptors and transporters. The TMT model could contribute to elucidate the role of dopaminergic system on two different CNS regions. Supported by PRIN 2008 - prot. 20089MANHH_002 and prot. 20089MANHH_003