Encoding a magic state with beyond break-even fidelity

To run large-scale algorithms on a quantum computer, error-correcting codes must be able to perform a fundamental set of operations, called logic gates, while isolating the encoded information from noise1-8. We can complete a universal set of logic gates by producing special resources called magic states9-11. It is therefore important to produce high-fidelity magic states to conduct algorithms while introducing a minimal amount of noise to the computation. Here we propose and implement a scheme to prepare a magic state on a superconducting qubit array using error correction. We find that our scheme produces better magic states than those that can be prepared using the individual qubits of the device. This demonstrates a fundamental principle of fault-tolerant quantum computing12, namely, that we can use error correction to improve the quality of logic gates with noisy qubits. Moreover, we show that the yield of magic states can be increased using adaptive circuits, in which the circuit elements are changed depending on the outcome of mid-circuit measurements. This demonstrates an essential capability needed for many error-correction subroutines. We believe that our prototype will be invaluable in the future as it can reduce the number of physical qubits needed to produce high-fidelity magic states in large-scale quantum-computing architectures.

Serum-to-urinary prostate-specific antigen ratio in patients with benign prostatic hyperplasia and prostate cancer

BACKGROUND

Prostate-specific antigen (PSA) is the single most important tumor marker in early detection and monitoring of prostate cancer (CaP). However, routine analysis of serum PSA concentrations does not allow differentiation between CaP and prostatic diseases. The aim of the present study was to evaluate the usefulness of the serum-to-urinary PSA ratio in a clinical setting.

MATERIALS AND METHODS

In a retrospective clinical study, we determined serum and urine PSA concentrations in 48 patients with benign prostatic hyperplasia (BPH) and 57 patients with histologically confirmed CaP.

RESULTS

The serum-to-urinary PSA ratio is able to discriminate BPH from CaP.

CONCLUSIONS

Determination of the serum-to-urinary PSA ratio enhances the specificity of PSA in screening for CaP and monitoring of patients with CaP under androgen deprivation therapy.

609 C --> T polymorphism in NAD(P)H:quinone oxidoreductase gene in patients with prostatic adenocarcinoma or benign prostatic hyperplasia

Allelic variations at the NQO1 locus encoding for NAD(P)H:quinone oxidoreductase have recently been implicated in carcinogenesis, cancer chemoprevention and chemotherapy. Two naturally occurring alleles differ at nucleotide position 609 with the variant allele leading to diminished or absent enzyme activity. Using polymerase chain reaction-restriction fragment length polymorphic analysis, NQO1 genotyping was performed in DNA from blood cells from 54 patients with prostatic adenocarcinoma, 49 patients with benign prostatic hyperplasia and 100 healthy control subjects. Prostatic adenocarcinoma patients and healthy controls demonstrated almost identical genotype distribution and frequencies of the variant allele (17.6 versus 17.5%). The variant allele was slightly more frequent in benign prostatic hyperplasia patients (23.5%). Established prostate cancer-derived cell lines LnCAP, DU-145, and PC-3 demonstrated NQO1 wild-type genotype. Our study does not support the hypothesis that the variant NQO1 allele is a risk modifier for prostatic adenocarcinoma and/or benign prostatic hyperplasia in the Caucasian population.

High-performance liquid chromatographic method for the determination of 3-methylindole (skatole) and indole in adipose tissue of pigs

A rapid method for the determination of skatole (3-methylindole) and indole in adipose tissue of pigs by reversed-phase high-performance liquid chromatography has been developed. Tissue samples were melted in a microwave oven, and 100 microliters of the liquid fat were dissolved in 1 ml of n-hexane and extracted with acetonitrile-water (75:25, v/v). Portions of 100 microliters of the solution were used for chromatographic analysis. Elution was performed on a reversed-phase column with a mobile phase composed of acetic acid and isopropanol (70:30, v/v). A fluorescence detector was used for quantification. The detection limit was 4 ng/g fat. The mean recoveries of added amounts of skatole and indole were 98.9 and 93.8%, respectively. The mean coefficients of variation were: inter-assay, 6.6% (skatole) and 8.8% (indole); intra-assay, 4.2% (skatole) and 2.9% (indole). Mean skatole concentrations in fat samples from boars (40 ng/g; n = 349) were not significantly higher than those from barrows (24 ng/g; n = 98).