Experimental Verification of Entanglement Generated in a Plasmonic System.

A core process in many quantum tasks is the generation of entanglement. It is being actively studied in a variety of physical settings-from simple bipartite systems to complex multipartite systems. In this work we experimentally study the generation of bipartite entanglement in a nanophotonic system. Entanglement is generated via the quantum interference of two surface plasmon polaritons in a beamsplitter structure, i.e., utilizing the Hong-Ou-Mandel (HOM) effect, and its presence is verified using quantum state tomography. The amount of entanglement is quantified by the concurrence and we find values of up to 0.77 ± 0.04. Verifying entanglement in the output state from HOM interference is a nontrivial task and cannot be inferred from the visibility alone. The techniques we use to verify entanglement could be applied to other types of photonic system and therefore may be useful for the characterization of a range of different nanophotonic quantum devices.

Long-term outcomes of direct acting antivirals in post-transplant advanced hepatitis C virus recurrence and fibrosing cholestatic hepatitis.

Long-term functional outcomes of sofosbuvir-based antiviral treatment were evaluated in a cohort study involving 16 Italian centres within the international compassionate use programme for post-transplant hepatitis C virus (HCV) recurrence. Seventy-three patients with cirrhosis (n=52) or fibrosing cholestatic hepatitis (FCH, n=21) received 24-week sofosbuvir with ribavirin±pegylated interferon or interferon-free sofosbuvir-based regimen with daclatasvir/simeprevir+ribavirin. The patients were observed for a median time of 103 (82-112) weeks. Twelve of 73 (16.4%) died (10 non-FCH, 2 FCH) and two underwent re-LT. Sustained virological response was achieved in 46 of 66 (69.7%): 31 of 47 (66%) non-FCH and 15 of 19 (79%) FCH patients. All relapsers were successfully retreated. Comparing the data of baseline with last follow-up, MELD and Child-Turcotte-Pugh scores improved both in non-FCH (15.3±6.5 vs 10.5±3.8, P<.0001 and 8.4±2.1 vs 5.7±1.3, P<.0001, respectively) and FCH (17.3±5.9 vs 10.1±2.8, P=.001 and 8.2±1.6 vs 5.5±1, P=.001, respectively). Short-treatment mortality was higher in patients with baseline MELD≥25 than in those with MELD<25 (42.9% vs 4.8%, P=.011). Long-term mortality was 53.3% among patients with baseline MELD≥20 and 7.5% among those with MELD<20 (P<.0001). Among deceased patients 75% were Child-Turcotte-Pugh class C at baseline, while among survivors 83.9% were class A or B (P<.0001). Direct acting antivirals-based treatments for severe post-transplant hepatitis C recurrence, comprising fibrosing cholestatic hepatitis, significantly improve liver function, even without viral clearance and permit an excellent long-term survival. The setting of severe HCV recurrence may require the identification of "too-sick-to-treat patients" to avoid futile treatments.

Experimental verification of multipartite entanglement in quantum networks.

Multipartite entangled states are a fundamental resource for a wide range of quantum information processing tasks. In particular, in quantum networks, it is essential for the parties involved to be able to verify if entanglement is present before they carry out a given distributed task. Here we design and experimentally demonstrate a protocol that allows any party in a network to check if a source is distributing a genuinely multipartite entangled state, even in the presence of untrusted parties. The protocol remains secure against dishonest behaviour of the source and other parties, including the use of system imperfections to their advantage. We demonstrate the verification protocol in a three- and four-party setting using polarization-entangled photons, highlighting its potential for realistic photonic quantum communication and networking applications.

Experimental demonstration of graph-state quantum secret sharing.

Quantum communication and computing offer many new opportunities for information processing in a connected world. Networks using quantum resources with tailor-made entanglement structures have been proposed for a variety of tasks, including distributing, sharing and processing information. Recently, a class of states known as graph states has emerged, providing versatile quantum resources for such networking tasks. Here we report an experimental demonstration of graph state-based quantum secret sharing--an important primitive for a quantum network with applications ranging from secure money transfer to multiparty quantum computation. We use an all-optical setup, encoding quantum information into photons representing a five-qubit graph state. We find that one can reliably encode, distribute and share quantum information amongst four parties, with various access structures based on the complex connectivity of the graph. Our results show that graph states are a promising approach for realising sophisticated multi-layered communication protocols in quantum networks.

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.

Physical activity in solid organ transplant recipients: organizational aspects and preliminary results of the Italian project.

Most of the difficulties when trying to realize the proposal to prescribe physical activity for transplantation patients come from patient attitudes and cultural beliefs that ignore the benefits of exercise, but there also are organizational aspects arising from the difficulties that these patients face in accessing supervised exercise facilities. To address these difficulties, the Italian study project "Transplant … and Now Sport" was developed based on a model of cooperation among transplantation specialists, sports physicians, and exercise specialists organized as a team combining their specific skills to effectively actuate the physical exercise programs. This preliminary report is based on 26 patients (16 male, 10 female; 47.8±10.0 years old; 21 kidney and 5 liver transplantations; time from transplantation 2.3±1.4 years) who performed prescribed and supervised exercises consisting of 3 sessions per week of aerobic and strengthening exercises for 1 year. Preliminary results show a significant decrease in body mass index (t=1.966; P<.05) and a significant increase in peak aerobic power (t=4.535; P<.01) and maximum workload (t=4.665; P<.01) on the incremental cycling test. Also maximum strength of knee extensors (t=2.933; P<.05) and elbow flexors (t=2.450; P<.05) and countermovement jump performance (t=2.303; P<.05) significantly increased. Creatinine and proteinuria tended to decrease, but the differences were not significant. In health-related quality of life assessed by the SF-36 questionnaire, the Bodily Pain, General Health, Vitality, Social Functioning, and Role Emotional scale scores showed a significant improvement (P<.05). Preliminary results of the study protocol "Transplant…and Now Sport" show the positive effects of the model based on cooperation among transplantation centers, sports medicine centers, and gyms in the administration of a supervised exercise prescription. These data should be considered a contribution to developing and promoting further detailed exercise protocols and to fostering improved posttransplantation health and survival, helping to ensure that physical activity becomes a safe routine medical treatment plan of patient management.

Experimental demonstration of a graph state quantum error-correction code.

Scalable quantum computing and communication requires the protection of quantum information from the detrimental effects of decoherence and noise. Previous work tackling this problem has relied on the original circuit model for quantum computing. However, recently a family of entangled resources known as graph states has emerged as a versatile alternative for protecting quantum information. Depending on the graph's structure, errors can be detected and corrected in an efficient way using measurement-based techniques. Here we report an experimental demonstration of error correction using a graph state code. We use an all-optical setup to encode quantum information into photons representing a four-qubit graph state. We are able to reliably detect errors and correct against qubit loss. The graph we realize is setup independent, thus it could be employed in other physical settings. Our results show that graph state codes are a promising approach for achieving scalable quantum information processing.

Sirolimus in liver transplant recipients: a large single-center experience.

Sirolimus (SRL) is a newer immunosuppressant whose possible benefits and side effects in comparison to calcineurin inhibitors (CNIs) still have to be addressed in the liver transplantation setting. We report the results of the use of SRL in 86 liver transplant recipients, 38 of whom received SRL as the main immunosuppressant in a CNI-sparing regimen. Indications for the use of SRL were: impaired renal function (n = 32), CNI neurotoxicity (n = 16), hepatocellular carcinoma (HCC) at high risk of recurrence (n = 21), recurrence of HCC (n = 6), de novo malignancies (n = 4), cholangiocarcinoma (n = 1), and the need to reinforce immunosuppression (n = 6). Among patients on SRL-based treatment, four episodes of acute rejection were observed, three of which occurred during the first postoperative month. Renal function significantly improved when sirolimus was introduced within the third postoperative month, while no change was observed when it was introduced later. Neurological symptoms resolved completely in 14/16 patients. The 3-year recurrence-free survival of patients with HCC on SRL was 84%. Sixty-two patients developed side effects that required drug withdrawal in seven cases. There was a reduced prevalence of hypertension and new-onset diabetes among patients under SRL. In conclusion, SRL was an effective immunosuppressant even when used in a CNI-sparing regimen. It was beneficial for patients with recently developed renal dysfunction or neurological disorders.

Experimental realization of Dicke states of up to six qubits for multiparty quantum networking.

We report the first experimental generation and characterization of a six-photon Dicke state. The produced state shows a fidelity of F=0.56+/-0.02 with respect to an ideal Dicke state and violates a witness detecting genuine six-qubit entanglement by 4 standard deviations. We confirm characteristic Dicke properties of our resource and demonstrate its versatility by projecting out four- and five-photon Dicke states, as well as four-photon Greenberger-Horne-Zeilinger and W states. We also show that Dicke states have interesting applications in multiparty quantum networking protocols such as open-destination teleportation, telecloning, and quantum secret sharing.

Assessment of liver fibrosis in transplant recipients with recurrent HCV infection: usefulness of transient elastography.

BACKGROUND: Progression of recurrent hepatitis C is accelerated in liver transplant recipients, leading to special need of non-invasive validated methods to estimate liver fibrosis. AIM: To assess the efficacy of liver stiffness measurement by transient elastography (Fibroscan) and serum parameters in predicting fibrosis stage in HCV-infected transplant recipients. METHODS: The correlation between liver fibrosis, assessed at liver histology on bioptic specimens obtained for clinical indications, and stiffness or clinico-serological indexes (Benlloch, APRI, Forns, Fibrotest and Doppler resistance index), was investigated in transplant recipients with recurrence of HCV chronic hepatitis. A total of 56 patients (of which 36 with all clinico-serological indexes), presenting with the following METAVIR fibrosis stage F1=38, F2=9, F3=8, F4=1, were enrolled in the study population. Differences between fibrosis stages were calculated by non-parametric analysis. The best cut-off for identifying significant fibrosis (F2-F4) was assessed by ROC curve analysis. RESULTS: Stiffness (median and range) was 7.7 KPa (range 4.2-13.9) in F1 and 17.0KPa (range 6.8-36.3) in >or=F2 (p<0.001). A stiffness cut-off of 10.1 KPa revealed 94% Sensitivity, 89% Specificity, 81% PPV and 94% NPV in differentiating F1 from F2-F4. The area under the receiver operator curve in the assessment of fibrosis was significantly higher for Liver stiffness (AUROC 0.943) than for any of the other non-invasive indexes (AUROCs ranging 0.591-0.815). CONCLUSIONS: Transient elastography of the liver provides good accuracy in identifying patients with significant fibrosis and performs better than non-invasive indexes based on clinico-serological parameters in transplant recipients.

Single-photon excitation of surface plasmon polaritons.

We provide the quantum-mechanical description of the excitation of surface plasmon polaritons on metal surfaces by single photons. An attenuated-reflection setup is described for the quantum excitation process in which we find remarkably efficient photon-to-surface plasmon wave-packet transfer. Using a fully quantized treatment of the fields, we introduce the Hamiltonian for their interaction and study the quantum statistics during transfer with and without losses in the metal.

Clinical trial: peg-interferon alfa-2b and ribavirin for the treatment of genotype-1 hepatitis C recurrence after liver transplantation.

BACKGROUND: Treatment of hepatitis C virus (HCV) recurrence after liver transplantation (LT) is difficult with low response rates. AIM: To assess the safety and efficacy of pegylated-interferon (PEG-IFN) alfa-2b + ribavirin (RBV) in patients with post-LT recurrent genotype-1 HCV and to establish stopping rules according to response. METHODS: Fifty-three patients with post-LT HCV recurrence were enrolled. Patients received PEG-IFN alfa-2b 1.0 micro/kg/week plus RBV 8-10 mg/kg/day for 24 weeks. Those with 'early virological response at week 24' (EVR24) continued treatment for 24 weeks (group A). Patients without EVR24 were randomized to continue (group B) or to discontinue (group C). RESULTS: Overall sustained virological response (SVR) was 26% (14/53). Alanine aminotransferase, rapid virological response, EVR12, EVR24, undetectable serum HCV-RNA at weeks 12 (cEVR12) and 24 (cEVR24) were related to SVR. cEVR12 and cEVR24 (OR: 14.7; 95% CI: 2.02-106.4) were independent predictors of SVR. All patients with SVR, had cEVR12. No patient in groups B and C achieved end-of-treatment response. One patient in group B had SVR. CONCLUSIONS: Pegylated-interferon alfa-2b was effective in one of four of patients with HCV genotype 1 after LT. Treatment should be discontinued in patients with no virological response at week 12. Further studies are needed to evaluate whether a longer treatment period may be beneficial in patients with > or =2 log10 drop in HCV-RNA at week 24.

Experimental realization of Deutsch's algorithm in a one-way quantum computer.

We report the first experimental demonstration of an all-optical one-way implementation of Deutsch's quantum algorithm on a four-qubit cluster state. All the possible configurations of a balanced or constant function acting on a two-qubit register are realized within the measurement-based model for quantum computation. The experimental results are in excellent agreement with the theoretical model, therefore demonstrating the successful performance of the algorithm.

High incidence of allograft dysfunction in liver transplanted patients treated with pegylated-interferon alpha-2b and ribavirin for hepatitis C recurrence: possible de novo autoimmune hepatitis?

BACKGROUND: Interferon may trigger autoimmune disorders, including autoimmune hepatitis, in immunocompetent patients. To date, no such disorders have been described in liver transplanted patients. METHODS: 9 of 44 liver transplanted patients who had been receiving pegylated-interferon alpha-2b and ribavirin for at least 6 months for hepatitis C virus (HCV) recurrence, developed graft dysfunction despite on-treatment HCV-RNA clearance in all but one case. Laboratory, microbiological, imaging and histological evaluations were performed to identify the origin of graft dysfunction. The International Autoimmune Hepatitis scoring system was also applied. RESULTS: In all cases infections, anastomoses complications and rejection were excluded, whereas the autoimmune hepatitis score suggested a "probable autoimmune hepatitis" (score from 10 to 14). Three patients developed other definite autoimmune disorders (overlap anti-mitochondrial antibodies (AMA)-positive cholangitis, autoimmune thyroiditis and systemic lupus erythematosus, respectively). In all cases, pre-existing autoimmune hepatitis was excluded. Anti-lymphocyte antibodies in immunosuppressive induction treatment correlated with the development of the disorder, whereas the use of granulocyte colony-stimulating factor to treat interferon-induced neutropenia showed a protective role. Withdrawal of antiviral treatment and treatment with prednisone resulted in different outcomes (five remissions and four graft failures with two deaths). CONCLUSIONS: De novo autoimmune hepatitis should be considered in differential diagnosis along with rejection in liver transplanted patients developing graft dysfunction while on treatment with interferon.

Experimental demonstration of decoherence-free one-way information transfer.

We report the experimental demonstration of a one-way quantum protocol reliably operating in the presence of decoherence. Information is protected by designing an appropriate decoherence-free sub-space for a cluster state resource. We demonstrate our scheme in an all-optical setup, encoding the information into the polarization states of four photons. A measurement-based one-way information-transfer protocol is performed with the photons exposed to severe symmetric phase-damping noise. Remarkable protection of information is accomplished, delivering nearly ideal outcomes.

Higher doses of peginterferon alpha-2b administered twice weekly improve sustained virological response in difficult-to-treat patients with chronic hepatitis C: results of a pilot randomized study.

SUMMARY: Beside substantial progress in treatment of chronic hepatitis C (CHC) particular patients (genotype 1/4, high viral load, previous nonresponse, cirrhosis) remain difficult to treat. The aim of our pilot randomized study was to compare efficacy and tolerability of standard doses of Peginterferon alpha-2b + ribavirin with higher doses of Peginterferon alpha-2b administered twice weekly + ribavirin. Sixty-five outpatients with CHC were subsequently enrolled. Group A (n = 22) received recommended doses of Peginterferon alpha-2b and group B (n = 43), received high doses twice weekly. Groups were comparable for baseline characteristics. All genotype 1/4 patients had high baseline viraemia. Sustained virological response (SVR) was significantly higher in group B among naïve patients (72%vs 25%, P = 0.024). A significantly higher rate of SVR was observed in group B both considering only genotype 1/4 patients, (46%vs 13%, P = 0.03) and grouping together genotype 1/4 naive and relapsers (57%vs 11%, P = 0.039). Discontinuation rate was 32% (7 of 22) in group A and 21% (9 [corrected] of 43) in group B. Our response rates are the highest reported for genotype 1/4 with high viraemia. Our pilot study supports the need of randomized studies to evaluate both viral kinetics and efficacy of high dose and twice weekly administration of Peginterferon alpha-2b in genotype 1/4 patients with high viraemia who may need personalized treatment schedules.

Renal sodium retention during upright posture in preascitic cirrhosis.

BACKGROUND: Renal sodium handling in preascitic cirrhosis is not clearly defined. This issue was addressed by evaluating renal sodium metabolism with different postures. METHODS: Renal function and plasma atrial natriuretic factor (ANF), aldosterone, and norepinephrine levels were determined after 2 hours of standing and 30, 60, and 120 minutes after taking up the supine position in 10 patients and 10 healthy subjects. RESULTS: When upright, patients' glomerular filtration rate and plasma ANF and norepinephrine levels did not differ from those of controls. Conversely, renal sodium excretion was reduced. Plasma aldosterone levels, which were slightly elevated, inversely correlated with renal sodium excretion. In the supine position, natriuresis increased by 308% +/- 99% in patients and 113% +/- 29% in controls (P = 0.016), so that it no longer differed between the two groups. Plasma norepinephrine and aldosterone levels decreased to a similar extent in controls and cirrhotics, whereas the increase in plasma ANF level was greater in patients. The changes in natriuresis correlated with those in plasma ANF levels and plasma aldosterone-ANF ratios in both controls and patients. CONCLUSIONS: Aldosterone-dependent sodium retention develops in preascitic cirrhosis during standing. The supine position is the means whereby standing-induced sodium retention can be balanced.

Severe hepatic failure occurring with T61 ingestion in an attempted suicide. Early recovery with the use of intravenous infusion of reduced glutathione.

A case of acute hepatic failure following ingestion of the veterinary euthanasia drug T61 is described. Presenting symptoms were drowsiness, disorientation, muscle hypertonia, and upper limb myoclonus, which faded within a few hours. Two days later, acute liver failure occurred, manifested as encephalopathy, jaundice, and a severe coagulopathy. The hepatic damage was thought to be due to the solvent dimethylformamide, which is the only known hepatotoxin included in the preparation utilized in the suicide attempt. High-dose (1.2 g/day) intravenous reduced glutathione was administered, with a rapid improvement of liver function. The patient was discharged after 17 days. Normalization of all liver function tests was achieved within two months. The favorable outcome in this case stands in contrast to the report of a previous case of lethal T61-induced hepatic failure. Although a different amount of dimethylformamide was ingested in each case (0.45 vs 0.60 ml/kg body wt) and individual differences in susceptibility to the effects of the hepatotoxic agent may have played a major role in these two cases, it is not unlikely that the infusion of high doses of glutathione to our patient contributed to her survival and hepatic recovery.

Bed-rest-induced hypernatriuresis in cirrhotic patients without ascites: does it contribute to maintain 'compensation'?

Renal function, plasma renin activity, plasma aldosterone concentration and urine excretion of free norepinephrine were evaluated in 13 cirrhotics without previous or ongoing ascites and in 13 healthy subjects, after 6 days of controlled electrolyte intake (40 mmol of Na and 70 mmol of K per day) and during 24 h of recumbency. Plasma concentrations of the atrial natriuretic peptide (ANP) were also measured in 8 patients and 8 controls. Despite a low-normal filtered load of sodium (14.6 +/- 1.2 vs. 17.1 +/- 1.2 mmol/min), cirrhotic patients showed supernormal natriuresis (141.5 +/- 14.1 vs. 78.8 +/- 8.6 mmol/day; p < 0.001). Whereas the fractional excretion of sodium in these patients was twice that of controls (0.70 +/- 0.05 vs. 0.36 +/- 0.04%; p < 0.001), potassium excretion (42.5 +/- 2.7 vs. 43.1 +/- 2.7 mmol/day) and urine volume (1270 +/- 98 vs. 1452 +/- 148 ml/day) did not differ. In cirrhotics, plasma renin activity was reduced (0.50 +/- 0.12 vs. 1.39 +/- 0.33 ng/ml/h; p < 0.02), and plasma aldosterone concentration tended to be lower (66 +/- 10 vs. 86 +/- 9 pg/ml; p = 0.09), while urine norepinephrine excretion did not significantly differ from controls (961 +/- 120 vs. 782 +/- 43 ng/h). ANP was higher in patients than in controls (92 +/- 17 vs. 48 +/- 9 pg/ml; p < 0.05). Natriuresis was directly correlated with ANP (r = 0.69, p < 0.005) and ANP/plasma aldosterone ratio (r = 0.63; p < 0.01) in patients and healthy subjects taken together.(ABSTRACT TRUNCATED AT 250 WORDS)