Deterministic preparation of superpositions of vacuum plus one photon by adaptive homodyne detection: experimental considerations

The preparation stage of optical qubits is an essential task in all the experimental setups employed for the test and demonstration of Quantum Optics principles. We consider a deterministic protocol for the preparation of qubits as a superposition of vacuum and one photon number states, which has the advantage to reduce the amount of resources required via phase-sensitive measurements using a local oscillator ('dyne detection'). We investigate the performances of the protocol using different phase measurement schemes: homodyne, heterodyne, and adaptive dyne detection (involving a feedback loop). First, we define a suitable figure of merit for the prepared state and we obtain an analytical expression for that in terms of the phase measurement considered. Further, we study limitations that the phase measurement can exhibit, such as delay or limited resources in the feedback strategy. Finally, we evaluate the figure of merit of the protocol for different mode-shapes handily available in an experimental setup. We show that even in the presence of such limitations simple feedback algorithms can perform surprisingly well, outperforming the protocols when simple homodyne or heterodyne schemes are employed.Comment: revised versio

Real-time three-dimensional ultrasound : a valuable new tool in preoperative assessment of complex congenital cardiac disease

Evaluating complex cardiac defects in small children preoperatively requires multiple diagnostic procedures including echocardiography, and also invasive methods such as cardiac catheterisation, computer-tomography and magnetic resonance imaging. This article assesses the complex anatomy of the atrioventricular valves in atrioventricular septal defect using bedside real-time three-dimensional echocardiography and comparing these results to the anatomic findings at the time of operative intervention.peer-reviewe

Solid-pseudopapillary tumor of the pancreas: A single center experience

open6noAim of this study was to review the institutional experience of solid-pseudopapillary tumors of the pancreas with particular attention to the problems of preoperative diagnosis and treatment. From 1997 to 2013, SPT was diagnosed in 18 patients among 451 pancreatic cystic neoplasms (3.7%). All patients underwent preoperative abdominal ultrasound, computed assisted tomography, and tumor markers (CEA and CA 19-9) determinations. In some instances, magnetic resonance, positron emission tomography, and endoscopic ultrasound with aspiration cytology were performed. There were two males and 16 females. Serum CA 19-9 was slightly elevated in one case. Preoperative diagnosis was neuroendocrine tumor (n = 2), mucinous tumor (n = 2), and SPT (n = 14). Two patients underwent previous operation before referral to our department: one explorative laparotomy and one enucleation of SPT resulting in surgical margins involvement. All patients underwent pancreatic resection associated with portal vein resection (n = 1) or liver metastases (n = 1). One patient died of metastatic disease, 77 months after operation, and 17 are alive and free with a median survival time of 81.5 months (range 36-228 months). Most of SPT can be diagnosed by CT or MRI, and the role of other diagnostic tools is very limited. We lack sufficient information regarding clinicopathologic features predicting prognosis. Caution is needed when performing limited resection, and long and careful follow-up is required for all patients after surgery.openBeltrame, Valentina; Pozza, Gioia; Dalla Bona, Enrico; Fantin, Alberto; Valmasoni, Michele; Sperti, CosimoBeltrame, Valentina; Pozza, Gioia; DALLA BONA, Enrico; Fantin, Alberto; Valmasoni, Michele; Sperti, Cosim

Characterization of entangling properties of quantum measurement via two-mode quantum detector tomography using coherent state probes

Entangled measurement is a crucial tool in quantum technology. We propose a new entanglement measure of multi-mode detection, which estimates the amount of entanglement that can be created in a measurement. To illustrate the proposed measure, we perform quantum tomography of a two-mode detector that is comprised of two superconducting nanowire single photon detectors. Our method utilizes coherent states as probe states, which can be easily prepared with accuracy. Our work shows that a separable state such as a coherent state is enough to characterize a potentially entangled detector. We investigate the entangling capability of the detector in various settings. Our proposed measure verifies that the detector makes an entangled measurement under certain conditions, and reveals the nature of the entangling properties of the detector. Since the precise characterization of a detector is essential for applications in quantum information technology, the experimental reconstruction of detector properties along with the proposed measure will be key features in future quantum information processing.Comment: 18 pages, 6 figure

Clinical course and outcomes of diagnosing Inflammatory Bowel Disease in children 10 years and under: retrospective cohort study from two tertiary centres in the United Kingdom and in Italy.

BACKGROUND: Most children with Inflammatory Bowel Disease (IBD) are diagnosed between 11 and 16 years of age, commonly presenting with features of typical IBD. Children with onset of gut inflammation under 5 years of age often have a different underlying pathophysiology, one that is genetically and phenotypically distinct from other children with IBD. We therefore set out to assess whether children diagnosed after the age of 5 years, but before the age of 11, have a different clinical presentation and outcome when compared to those presenting later. METHODS: Retrospective cohort study conducted at two European Paediatric Gastroenterology Units. Two cohorts of children with IBD (total number = 160) were compared: 80 children diagnosed between 5 and 10 years (Group A), versus 80 children diagnosed between 11 and 16 (Group B). Statistical analysis included multiple logistic regression. RESULTS: Group A presented with a greater disease activity (p = 0.05 for Crohn's disease (CD), p = 0.03 for Ulcerative Colitis (UC); Odds Ratio 1.09, 95 % Confidence Interval: 1.02-1.1), and disease extent (L2 location more frequent amongst Group A children with CD (p = 0.05)). No significant differences were observed between age groups in terms of gastro-intestinal and extra-intestinal signs and symptoms at disease presentation, nor was there a difference in the number of hospitalisations due to relapsing IBD during follow-up. However, children in Group A were treated earlier with immunosuppressants and had more frequent endoscopic assessments. CONCLUSION: While clinicians feel children between 5 and 10 years of age have a more severe disease course than adolescents, our analysis also suggests a greater disease burden in this age group. Nevertheless, randomized trials to document longer-term clinical outcomes are urgently needed, in order to address the question whether a younger age at disease onset should prompt per se a more "aggressive" treatment. We speculate that non-clinical factors (e.g. genetics, epigenetics) may have more potential to predict longer term outcome than simple clinical measures such as age at diagnosis

Pregnane X receptor and constitutive androstane receptor modulate differently CYP3A-mediated metabolism in earlyand late-stage cholestasis

AIM: To ascertain whether cholestasis affects the expression of two CYP3A isoforms (CYP3A1 and CYP3A2) and of pregnane X receptor (PXR) and constitutive androstane receptor (CAR). METHODS: Cholestasis was induced by bile duct ligation in 16 male Wistar rats; whereas 8 sham-operated rats were used as controls. Severity of cholestasis was assessed on histological examination of liver sections, and serum concentrations of albumin, AST, ALT, GGT, ALPK and bilirubin. Gene and protein expressions of PXR, CAR, CYP3A1 and CYP3A2 were assessed by means of qRT-PCR and Western blot, respectively. Alterations in CYP3A activity were measured by calculating the kinetic parameters of 4-OH and 1'-OH-midazolam hydroxylation, marker reactions for CYP3A enzymes. RESULTS: The mRNA and protein expression of CYP3A1 increased significantly in mild cholestasis (P < 0.01). At variance, mRNA and protein expression of CYP3A2 didn't change in mild cholestasis, whereas the expression and activity of both CYP3A1 and CYP3A2 decreased dramatically when cholestasis became severe. Consistently with these observations, the nuclear expression of both PXR and CAR, which was measured because they both translocate into the cell nucleus after their activation, virtually disappeared in the late stage of cholestatic injury, after an initial increase. These results indicate that early- and late-stage cholestasis affects CYP3A-mediated drug metabolism differently, probably as consequence of the different activation of PXR and CAR. CONCLUSION: Early- and late-stage cholestasis affects CYP3A-mediated drug metabolism differently. PXR and CAR might be targeted therapeutically to promote CYP3A-mediated liver detoxification