Computing on Anonymous Quantum Network

This paper considers distributed computing on an anonymous quantum network, a network in which no party has a unique identifier and quantum communication and computation are available. It is proved that the leader election problem can exactly (i.e., without error in bounded time) be solved with at most the same complexity up to a constant factor as that of exactly computing symmetric functions (without intermediate measurements for a distributed and superposed input), if the number of parties is given to every party. A corollary of this result is a more efficient quantum leader election algorithm than existing ones: the new quantum algorithm runs in O(n) rounds with bit complexity O(mn^2), on an anonymous quantum network with n parties and m communication links. Another corollary is the first quantum algorithm that exactly computes any computable Boolean function with round complexity O(n) and with smaller bit complexity than that of existing classical algorithms in the worst case over all (computable) Boolean functions and network topologies. More generally, any n-qubit state can be shared with that complexity on an anonymous quantum network with n parties.Comment: 25 page

Power of Quantum Computation with Few Clean Qubits

This paper investigates the power of polynomial-time quantum computation in which only a very limited number of qubits are initially clean in the |0> state, and all the remaining qubits are initially in the totally mixed state. No initializations of qubits are allowed during the computation, nor intermediate measurements. The main results of this paper are unexpectedly strong error-reducible properties of such quantum computations. It is proved that any problem solvable by a polynomial-time quantum computation with one-sided bounded error that uses logarithmically many clean qubits can also be solvable with exponentially small one-sided error using just two clean qubits, and with polynomially small one-sided error using just one clean qubit. It is further proved in the case of two-sided bounded error that any problem solvable by such a computation with a constant gap between completeness and soundness using logarithmically many clean qubits can also be solvable with exponentially small two-sided error using just two clean qubits. If only one clean qubit is available, the problem is again still solvable with exponentially small error in one of the completeness and soundness and polynomially small error in the other. As an immediate consequence of the above result for the two-sided-error case, it follows that the TRACE ESTIMATION problem defined with fixed constant threshold parameters is complete for the classes of problems solvable by polynomial-time quantum computations with completeness 2/3 and soundness 1/3 using logarithmically many clean qubits and just one clean qubit. The techniques used for proving the error-reduction results may be of independent interest in themselves, and one of the technical tools can also be used to show the hardness of weak classical simulations of one-clean-qubit computations (i.e., DQC1 computations).Comment: 44 pages + cover page; the results in Section 8 are overlapping with the main results in arXiv:1409.677

How should we treat acute kidney injury caused by renal congestion?

Decreased kidney function is associated with increased risk of cardiovascular events and mortality, and heart failure (HF) is a well-known risk factor for renal dysfunction. Acute kidney injury (AKI) in patients with HF often is attributed to prerenal factors, such as renal hypoperfusion and ischemia as a result of decreased cardiac output. Another such factor is reduction of absolute or relative circulating blood volume, with the decrease in renal blood flow leading to renal hypoxia followed by a decrease in the glomerular filtration rate. However, renal congestion is increasingly being recognized as a potential cause of AKI in patients with HF. Increased central venous pressure and renal venous pressure lead to increased renal interstitial hydrostatic pressure and a reduction of the glomerular filtration rate. Both decreased kidney function and renal congestion have been shown to be important prognostic factors of HF, and adequate control of congestion is important for improving kidney function. Loop and thiazide diuretics are recommended as standard therapies to reduce volume overload. However, these agents are associated with worsening renal function even though they are effective for improving congestive symptoms. There is growing interest in tolvaptan, which can improve renal congestion by increasing excretion of free water and decreasing the required dose of loop diuretic, thereby improving kidney function. This review summarizes renal hemodynamics, the pathogenesis of AKI due to renal ischemia and renal congestion, and diagnosis and treatment options for renal congestion

Feasibility of lung transplantation from donors mechanically ventilated for prolonged periods

PURPOSE: When patients are mechanically ventilated for more than 5 days, they are usually declined as donors for lung transplantation (LTx); thus, the long-term outcomes of LTx from such donors remain unclear. We investigated the feasibility of LTx from donors that had been mechanically ventilated for prolonged periods. METHODS: The subjects of this retrospective comparative investigation were 31 recipients of LTx from donors who had been mechanically ventilated for RESULTS: The median duration of donor mechanical ventilation was 3 days in the short-term group and 8.5 days in the long-term group. However, other than the difference in the duration of donor ventilation, there were no significant differences in the clinical characteristics of the donors or recipients between the groups. The overall survival rate after LTx was comparable between the long-term group and short-term group (5-year survival rate, 66.6% vs. 75.2%). CONCLUSION: The potential inclusion of donors who have been on mechanical ventilation for more than 5 days could be a feasible strategy to alleviate donor organ shortage

Right single lung transplantation using an inverted left donor lung: interposition of pericardial conduit for pulmonary venous anastomosis-a case report

BACKGROUND: Lung transplantation (LTx) is still limited by the shortage of suitable donor lungs. Developing flexible surgical procedures can help to increase the chances of LTx by unfolding recipient-to-donor matching options based on the pre-existing organ allocation concept. We report a case in which a successful left-to-right inverted LTx was completed using the interposition of a pericardial conduit for pulmonary venous anastomosis. CASE PRESENTATION: A left lung graft was offered to a 59-year-old male who had idiopathic pulmonary fibrosis with predominant damage in the right lung. He had been prescribed bed rest with constant oxygen inhalation through an oxymizer pendant and had been on the waiting list for 20 months. Considering the condition of the patient (LAS 34.3) and the scarcity of domestic organ offers, the patient was highly likely to be incapable of tolerating any additional waiting time for another donor organ if he was unable to accept the presently reported offer of a left lung. Eventually, we decided to transplant the left donor lung into the right thorax of the recipient. Because of the anterior-posterior position gap of the hilar structures, the cuff lengths of the pulmonary veins had to be adjusted. The patient did not develop any anastomotic complications after the transplantation. CONCLUSIONS: A left-to-right inverted LTx is technically feasible using an autologous pericardial conduit for pulmonary venous anastomosis in selected cases. This technique provides the potential benefit of resolving challenging situations in which surgeons must deal with a patient's urgency and the logistical limitations of organ allocation

Reduction of T-Box 15 gene expression in tumor tissue is a prognostic biomarker for patients with hepatocellular carcinoma

Genome-wide analysis is widely applied to detect molecular alterations during oncogenesis and tumor progression. We analyzed DNA methylation profiles of hepatocellular carcinoma (HCC), and investigated the clinical role of most heypermethylated of tumor, encodes T-box 15 (TBX15), which was originally involved in mesodermal differentiation. We conducted a genome-wide analysis of DNA methylation of tumor and non-tumor tissue of 15 patients with HCC, and revealed TBX15 was the most hypermethylated gene of tumor (Beta-value in tumor tissue = 0.52 compared with non-tumor tissue). Another validation set, which comprised 58 HCC with radical resection, was analyzed to investigate the relationships between tumor phenotype and TBX15 mRNA expression. TBX15 mRNA levels in tumor tissues were significantly lower compared with those of nontumor tissues (p < 0.0001). When we assigned a cutoff value = 0.5-fold, the overall survival 5-year survival rates of the low-expression group (n = 17) were significantly shorter compared with those of the high-expression group (n = 41) (43.3% vs. 86.2%, p = 0.001). Multivariate analysis identified low TBX15 expression as an independent prognostic factor for overall and disease-free survival. Therefore, genome-wide DNA methylation profiling indicates that hypermethylation and reduced expression of TBX15 in tumor tissue represents a potential biomarker for predicting poor survival of patients with HCC