Quantum control of a cat qubit with bit-flip times exceeding ten seconds.

Quantum bits (qubits) are prone to several types of error as the result of uncontrolled interactions with their environment. Common strategies to correct these errors are based on architectures of qubits involving daunting hardware overheads1. One possible solution is to build qubits that are inherently protected against certain types of error, so the overhead required to correct the remaining errors is greatly reduced2-7. However, this strategy relies on one condition: any quantum manipulations of the qubit must not break the protection that has been so carefully engineered5,8. A type of qubit known as a cat qubit is encoded in the manifold of metastable states of a quantum dynamical system, and thereby acquires continuous and autonomous protection against bit-flips. Here, in a superconducting-circuit experiment, we implemented a cat qubit with bit-flip times exceeding 10 s. This is an improvement of four orders of magnitude over previously published cat-qubit implementations. We prepared and imaged quantum superposition states, and measured phase-flip times greater than 490 ns. Most importantly, we controlled the phase of these quantum superpositions without breaking the bit-flip protection. This experiment demonstrates the compatibility of quantum control and inherent bit-flip protection at an unprecedented level, showing the viability of these dynamical qubits for future quantum technologies.

Risk factors for reoperation due to chronic groin postherniorrhaphy pain.

BACKGROUND: Chronic groin postherniorrhaphy pain (CGPP) is common and sometimes so severe that surgical treatment is necessary. The aim of this study was to identify risk factors for being reoperated due to CGPP. METHODS: All 195,707 repairs registered in the Swedish Hernia Register between 1999 and 2011 were included in the study. Out of these, 28,947 repairs were excluded since they were registered as procedures on the same patient after a previous repair. Age, gender, hernia anatomy (indirect reference), method of repair (anterior sutured repair reference) and postoperative complications were included in a multivariate Cox analysis with reoperation due to CGPP as endpoint. RESULTS: Of the patients included in the study cohort, 218 (0.13%) later underwent reoperation due to CGPP, including 31 (14%) women. Median age at the primary repair was 61.5 years. Risk factors for being reoperated were age < median [hazard ratio (HR) 3.03, 95% confidence interval (CI) 2.22-4.12], female gender (HR 2.13, CI 1.41-3.21), direct hernia (HR 1.35, CI 1.003-1.81), other hernia (HR 6.03, CI 3.08-11.79), Lichtenstein repair (HR 2.22, CI 1.16-4.25), plug repair (HR 3.93, CI 1.96-7.89), other repair (HR 2.58, CI 1.08-6.19), bilateral repair (HR 2.58, CI 1.43-4.66) and postoperative complication (HR 4.40, CI 3.25-5.96). CONCLUSIONS: Risk factors for being reoperated due to CGPP in this cohort included low age, female gender, a direct hernia, a previous Lichtenstein or plug repair, bilateral repair and postoperative complications. Further research on how to avoid CGPP and explore the effectiveness of surgery for CGPP is necessary.

Elective splenectomy in the elderly--perioperative and long-term course.

BACKGROUND: The hazards of elective splenectomy in the elderly have not been thoroughly investigated. The aim was to assess such a well-defined cohort with respect to perioperative and long-term outcome. METHODS: Fifty-two consecutively splenectomised patients during the period 1971-1995, aged 65 years or older, were followed until death (44 cases) or the end of 1999 (8 cases). RESULTS: No intraoperative deaths occurred, while three patients (5.8%) died postoperatively in the 1970s. Twenty-four patients suffered from thirty-four postoperative complications, dominated by infections and haematomas. No differences were seen comparing patients with and without complications related to the American Society of Anesthesiologists' classes, total transfusion rate, steroid medication, preoperative risk diseases, "giant spleens" or the time period during which the operations were performed. In 69% of the patients, the splenectomy was beneficial. During the long-term follow-up, 25 patients suffered from 59 infectious and thromboembolic episodes and 1 surgical complication. The dominating causes of death were the primary disease (29%), myocardial infarction (20%), sepsis (12%) and cerebrovascular lesions (12%), i.e. not directly related to late effects of the operation. CONCLUSION: High-risk patients older than 65 years with haematological disorders can safely undergo splenectomy with a low mortality rate and a reasonable rate of morbidity. The long-term course demonstrates a fair response rate, minimal surgically related complications, but thromboembolic and infectious events, and the majority of deaths unrelated to late effects of the splenectomy.

Selected contribution: role of spleen emptying in prolonging apneas in humans.

This study addressed the interaction between short-term adaptation to apneas with face immersion and erythrocyte release from the spleen. Twenty healthy volunteers, including ten splenectomized subjects, participated. After prone rest, they performed five maximal-duration apneas with face immersion in 10 degrees C water, with 2-min intervals. Cardiorespiratory parameters and venous blood samples were collected. In subjects with spleens, hematocrit and hemoglobin concentration increased by 6.4% and 3.3%, respectively, over the serial apneas and returned to baseline 10 min after the series. A delay of the physiological breaking point of apnea, by 30.5% (17 s), was seen only in this group. These parameters did not change in the splenectomized group. Plasma protein concentration, preapneic alveolar PCO2, inspired lung volume, and diving bradycardia remained unchanged throughout the series in both groups. Serial apneas thus triggered the hematological changes that have been previously observed after long apneic diving shifts; they were rapidly reversed and did not occur in splenectomized subjects. This suggests that splenic contraction occurs in humans as a part of the diving response and may prolong repeated apneas.

Nonrandom chromosomal aberrations and cytogenetic heterogeneity in gallbladder carcinomas.

Chromosome banding analysis of 11 short-term cultured gallbladder carcinomas revealed acquired clonal aberrations in seven tumors (five primary and two metastases). Three of these had one clone, whereas the remaining four were cytogenetically heterogeneous, displaying two to seven aberrant clones. Of a total of 21 abnormal clones, 18 had highly complex karyotypes and three exhibited simple numerical deviations. Double minutes and homogeneously staining regions were observed in one and two carcinomas, respectively. To characterize the karyotypic profile of gallbladder cancer more precisely, we have combined the present findings with our three previously reported cases, thereby providing the largest cytogenetic database on this tumor type to date. A total of 287 chromosomal breakpoints were identified, 251 of which were found in the present study. Chromosome 7 was rearranged most frequently, followed by chromosomes 1, 3, 11, 6, 5, and 8. The bands preferentially involved were 1p32, 1p36, 1q32, 3p21, 6p21, 7p13, 7q11, 7q32, 19p13, 19q13, and 22q13. Nine recurrent abnormalities could, for the first time, be identified in gallbladder carcinoma: del(3)(p13), i(5)(p10), del(6)(q13), del(9)(p13), del(16)(q22), del(17)(p11), i(17)(q10), del(19)(p13), and i(21)(q10). The most common partial or whole-arm gains involved 3q, 5p, 7p, 7q, 8q, 11q, 13q, and 17q, and the most frequent partial or whole-arm losses affected 3p, 4q, 5q, 9p, 10p, 10q, 11p, 14p, 14q, 15p, 17p, 19p, 21p, 21q, and Xp. These chromosomal aberrations and imbalances provide some starting points for molecular analyses of genomic regions that may harbor genes of pathogenetic importance in gallbladder carcinogenesis. Genes Chromosomes Cancer 26:312-321, 1999.

Clonal chromosomal abnormalities in congenital bile duct dilatation (Caroli's disease).

BACKGROUND: Caroli's disease is a rare congenital disorder characterised by cystic dilatation of the intrahepatic bile ducts and an increased risk of cholangiocellular carcinoma. The cause is unknown, but occasional familial clustering suggests that some cases are inherited, in particular when occurring in association with polycystic kidney disease and germline PKD1 gene mutations. To date, no gene responsible for familial isolated Caroli's disease has been identified, and no genetic investigations of liver tissue from patients with Caroli's disease have been reported. PATIENT/METHOD: A liver biopsy specimen from a patient with isolated Caroli's disease, without any signs of cholangiocellular carcinoma, was short term cultured and cytogenetically investigated after G banding with Wright's stain. RESULT: Cytogenetic analysis disclosed the karyotype 45-47,XX,der(3)t(3;8)(p23;q13), +2mar[cp6]/46,XX[18]. CONCLUSIONS: The finding of an unbalanced translocation between chromosomes 3 and 8 suggests that loss of distal 3p and/or gain of 8q is of pathogenetic importance in Caroli's disease. Alternatively, structural rearrangements of genes located in 3p23 and 8q13 may be of the essence. These chromosomal breakpoints may also pinpoint the location of genes involved in inherited forms of Caroli's disease not associated with polycystic kidney disease.

Cytogenetic analyses of secondary liver tumors reveal significant differences in genomic imbalances between primary and metastatic colon carcinomas.

To investigate if karyotypic features of secondary liver tumors may provide diagnostic information and if the cytogenetic patterns of primary and metastatic colorectal carcinomas (CRC) are different, 33 liver metastases were analyzed: 25 CRC, 4 small intestine carcinoids, 1 ovarian carcinoid, 1 lobular breast cancer, 1 head-and-neck squamous cell carcinoma, and 1 uveal malignant melanoma. Chromosomal aberrations were detected in 24 cases, whereas 5 had normal karyotypes and 4 were uninformative due to lack of mitoses. Trisomy 12 was detected in 2 small intestine carcinoids, suggesting that +12 may be of pathogenetic importance in this tumor type. The breast and head-and-neck carcinomas and the uveal melanoma displayed aberrations previously reported as characteristic in primary tumors, e.g., der(1;16) and deletion of 3p in the breast cancer, losses of 3p and 8p and partial gain of 8q in the head-and-neck carcinoma, and monosomy 3 and i(8)(q10) in the uveal melanoma, indicating that cytogenetic investigations provide important diagnostic information in secondary liver tumors. In the 18 CRC metastases with chromosomal abnormalities, the cytogenetic findings agreed well with previously reported primary CRC. Common numerical abnormalities included gains of chromosomes 7, 11, 13, and 20, and losses of Y, 4, 18, 21, and 22. Structural rearrangements most often affected chromosome bands 1p13, 1q10, 3p21, 5q10, 5q11, 7q10, 8q10, 8q11, 12q13, 16p13, 17p11, 20p13, 20p11, and 20q10, and frequently resulted in losses of 1p, 8p, and 17p, and gains of 5p, 6p, 7p, 8q, and 20q. Comparing the present cases with primary CRC previously analyzed in our department revealed that additional gains of 6p, 6q, 7p, and 20q, and losses of 1p, 4p, 4q, 8p, 18p, 18q, and 22 were more common (P < 0.05) in the metastases, suggesting that these genomic sites harbor genes of importance in the metastatic process of CRC.

Frequent rearrangements of chromosomes 1, 7, and 8 in primary liver cancer.

Fifteen primary liver carcinomas (PLCs), including 12 hepatocellular carcinomas and three cholangiocellular carcinomas, were investigated cytogenetically after short-term culture. Ten tumors displayed clonal chromosomal abnormalities, whereas only normal karyotypes were detected in four cases, and one sample failed to grow in vitro. Structural rearrangements most often involved chromosomes 1, 7, and 8 and chromosome bands 1p36, 1q25, 3q10, 5q13, 6p10, 7p15, 7q22, 7q32, 8q10, 8q13, 14q10, and 17p11. Frequent genomic imbalances included gains of 1q, 3q, 6p, 7p, and 8q and losses of 1p, 8p, 10q, 14p, 17p, and 19p. A compilation of findings for all 19 cytogenetically abnormal PLCs reported to date, including the present cases, reveals that structural aberrations particularly affect 1p11, 1p22, 1p32, 1p34, 1p36, 1q25, 7p15, 7q22, 8q10, 8q13, 14q10, 16q24, and 17p11, and that the abnormalities frequently result in overrepresentation of 1q, 3q, 6p, 7p10-14, 8q, and 17q and underrepresentation of 1p34-36, 6q27, 7q32-qter, 8p, 13p, 14p, 16q24, and 17p. These genomic regions are likely to harbor genes of importance in hepatocarcinogenesis, and the present cytogenetic mapping may hence be of value for further molecular genetic investigations of PLC.

Cytogenetic abnormalities and clonal evolution in an adult hepatoblastoma.

Hepatoblastomas usually occur in children < 3 years of age, and only occasional adult cases have been described. To date, 20 cytogenetically abnormal childhood hepatoblastomas have been reported. Karyotypic investigations have shown that most hepatoblastomas are diploid or hyperdiploid, often displaying trisomies for chromosomes 2 and 20. We have cytogenetically investigated an adult hepatoblastoma for which no previous karyotypic data exist. A hypertriploid stemline with multiple numerical and structural chromosomal aberrations, including +2 and +20, was found. In addition, the tumor displayed extensive clonal evolution with 11 subclones. Although the tumor thus displayed some chromosomal abnormalities commonly observed in childhood tumors, providing further support for the importance of these abnormalities in the development of hepatoblastoma, the level of genomic complexity seen in the present case has never been described in childhood hepatoblastomas and may suggest a different etiology or pathogenesis.

EURAMIC Study: antioxidants, myocardial infarction and breast cancer. Design and main hypotheses.

Epidemiological studies have not given sufficient evidence yet for the role of antioxidant nutrients in the prevention of cardiovascular disease. As regards cancer, an inverse association between beta-carotene intake and specific types of cancer, especially lung cancer, has been shown. For other cancer sites and other antioxidants, the association is less clear. The EURAMIC Study, an EC Concerted Action, is a case-control study conducted in 11 countries, in which the combined effect of vitamin E, beta-carotene and selenium, in relation to fatty acid intake, will be examined. The disease endpoints are acute myocardial infarction and early-stage breast cancer. The broad range of antioxidant intake, the use of biomarkers of exposure, and the analysis of pooled data will allow an estimate of the strength of the putative beneficial effect. In this paper the background and design of the study will be introduced.

Negative Haemoccult test in malignant and premalignant lesions of the colon. Validation of the Haemoccult test with total colonoscopy.

To date, no published report on a trial has provided sufficiently strong evidence of the accuracy of the Haemoccult Test assessed by false-negative error, and validated on the basis of a complete colonoscopy of all patients. Total colonoscopy (up to the cecum) was performed on 534 patients whose stools had been tested for occult blood. The results of the colonoscopy were classified as follows: --expected continual bleeding (target lesions: carcinoma, polyps greater than or equal to 10 mm) --intermittant bleeding (polyps less than 10 mm, colitis, etc.), and --no source of bleeding. Results were regarded as false-negative in patients who were found to have a target lesion (carcinoma, polyp greater than or equal to 10 mm) following a negative Haemoccult test. Apart from positive and negative prognostic values, sensitivity and specificity were taken into account as characteristics for the quality of the test. Following a positive Haemoccult test result 46 of the 534 patients were found to have polyps greater than or equal to 10 mm and 22 carcinomas; following negative Haemoccult test results 31 patients were found to have polyps measuring greater than or equal to 10 mm in diameter and 2 carcinomas. On the basis of the chosen classification a false-negative Haemoccult result was established in 8.6% and a false-positive result in 4.3%. The Haemoccult test showed a sensitivity of 67% and a specificity of 93% in patients with target lesions or patients without a source of bleeding.