Fast two-qubit logic with holes in germanium.

Universal quantum information processing requires the execution of single-qubit and two-qubit logic. Across all qubit realizations1, spin qubits in quantum dots have great promise to become the central building block for quantum computation2. Excellent quantum dot control can be achieved in gallium arsenide3-5, and high-fidelity qubit rotations and two-qubit logic have been demonstrated in silicon6-9, but universal quantum logic implemented with local control has yet to be demonstrated. Here we make this step by combining all of these desirable aspects using hole quantum dots in germanium. Good control over tunnel coupling and detuning is obtained by exploiting quantum wells with very low disorder, enabling operation at the charge symmetry point for increased qubit performance. Spin-orbit coupling obviates the need for microscopic elements close to each qubit and enables rapid qubit control with driving frequencies exceeding 100 MHz. We demonstrate a fast universal quantum gate set composed of single-qubit gates with a fidelity of 99.3 per cent and a gate time of 20 nanoseconds, and two-qubit logic operations executed within 75 nanoseconds. Planar germanium has thus matured within a year from a material that can host quantum dots to a platform enabling two-qubit logic, positioning itself as an excellent material for use in quantum information applications.

Spin Lifetime and Charge Noise in Hot Silicon Quantum Dot Qubits.

We investigate the magnetic field and temperature dependence of the single-electron spin lifetime in silicon quantum dots and find a lifetime of 2.8 ms at a temperature of 1.1 K. We develop a model based on spin-valley mixing and find that Johnson noise and two-phonon processes limit relaxation at low and high temperature, respectively. We also investigate the effect of temperature on charge noise and find a linear dependence up to 4 K. These results contribute to the understanding of relaxation in silicon quantum dots and are promising for qubit operation at elevated temperatures.

Blood group O: A novel risk factor for increased postpartum blood loss?

INTRODUCTION: Blood group O is known to be associated with lower levels of von Willebrand factor (VWF) and with increased bleeding complications. The influence of blood group O on postpartum blood loss was assessed by a few studies, however, without adjustment for important obstetric risk factors for postpartum blood loss. AIM: Aim of this study was to investigate whether women with blood group O exhibit increased blood loss after delivery in consideration of established risk factors for postpartum bleeding. METHODS: A total of 1487 patients were prospectively included into this cohort study. Blood loss was assessed by estimated blood loss (in mL), and drop of haemoglobin (Δ haemoglobin) was calculated. Association of blood loss with risk factors (such as blood group O, cervical tears, morbidly adherent placenta, placenta praevia and uterine atony amongst others) was assessed with appropriate tests. Significant variables were entered into a stepwise multivariate regression analysis. RESULTS: Women with blood group O showed a significantly higher blood loss when compared to women with blood group non-O (529.2 mL ± 380.4 mL and 490.5 mL ± 276.4 mL, respectively, P = .024)). The increased blood loss in women with blood group O remained significant after multivariate regression analysis (difference 47 mL, P = .019). CONCLUSION: This is the first study reporting significantly increased blood loss following delivery in women with blood group O after adjustment for major risk factors for postpartum blood loss. Albeit having a statistically significant, but clinically minor effect on absolute blood loss, blood group O carriers may suffer from aggravated bleeding in the presence of additional obstetric bleeding pathologies.

Quadrupole shift of nuclear magnetic resonance of donors in silicon at low magnetic field.

Shifts from the expected nuclear magnetic resonance frequencies of antimony and bismuth donors in silicon of greater than a megahertz are observed in electrically detected magnetic resonance spectra. Defects created by ion implantation of the donors are discussed as the source of effective electric field gradients generating these shifts via quadrupole interaction with the nuclear spins. The experimental results are modeled quantitatively by molecular orbital theory for a coupled pair consisting of a donor and a spin-dependent recombination readout center.

[Primary liver tumours in childhood]. / Primäre Lebertumoren im Kindesalter.

The reported prevalence of focal liver lesions in adult patients and children is different. The article discusses pediatric liver tumors under the criteria of histopathology and contrast enhanced ultrasound (CEUS) features. Aim of this article is also to support the already established Pediatric Registry of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) to collect data on safety and applications of ultrasound contrast agents in children (www.efsumb.org).

von Willebrand factor, clotting factors, and clotting inhibitors in apheresis platelet concentrates.

BACKGROUND: Apheresis platelet concentrates (APCs) are usually stored in citrated plasma at 22°C. The stability of coagulation proteins-von Willebrand factor (vWF), clotting factors (CFs), and their inhibitors-has often been described in association with the storage of thawed plasma. However, fewer data are available regarding changes in APCs. STUDY DESIGN AND METHODS: We measured CF activities and inhibitors in APCs on the day of manufacture (Day 0) and on Days 4, 5, and 7. vWF was determined by measuring vWF antigen (vWF:Ag) and vWF ristocetin cofactor (vWF:RCo) and by multimer analysis. RESULTS: Twenty-one PCs obtained by plateletpheresis were studied. Major changes were observed for Factor (F)VIII (37% loss of activity within 4 days), FV (20% within 4 days), and protein S (76% within 4 days). All other CF activities remained higher than 80% over the 7 days. Fibrinogen and the inhibitors antithrombin and protein C remained quite stable. FXI, FXII, and FXIII actually increased during storage (8, 11, and 12% within 4 days). vWF:Ag increased during storage of APCs by 2% per day, with a relative loss of vWF:RCo and high-molecular-weight multimers. CONCLUSION: Even after 7 days of storage at 22°C, the hemostatic potential of the plasma content in APCs was roughly preserved. The increase in FXII antigen indicates that this CF may also be stored in platelets; however, this has not yet been described.

Nonlinear pulse propagation in a quantum dot laser.

We investigate the nonlinear propagation of an ultra-short, 150 fs, optical pulse along the waveguide of a quantum dot (QD) laser operating above threshold. We demonstrate that among the various nonlinear processes experienced by the propagating pulse, four-wave mixing (FWM) between the pulse and the two oscillating counter-propagating cw fields of the laser is the dominant one. FWM has two important consequences. One is the creation of a spectral hole located in the vicinity of the cw oscillating frequency. The width of the spectral hole is determined by an effective carrier and gain relaxation time. The second is a modification of the shape of the trailing edge of the pulse. The wave mixing involves first and second order processes which result in a complicated interaction among several fields inside the cavity, some of which are cw while the others are time varying, all propagating in both directions. The nonlinear pulse propagation is analyzed using two complementary theoretical approaches. One is a semi-analytical model which considers only the wave mixing interaction between six field components, three of which propagate in each direction (two cw fields and four time-varying signals). This model predicts the deformation of the tail of the output signal by a secondary idler wave, produced in a cascaded FWM process, which co-propagates with the original injected pulse. The second approach is a finite-difference time-domain simulation, which considers also additional nonlinear effects, such as gain saturation and self-phase modulation. The theoretical results are confirmed by a series of experiments in which the time dependent amplitude and phase of the pulse after propagation are measured using the cross-frequency-resolved optical gating technique.

Development of an AI based automated analysis of pediatric Apple Watch iECGs.

Introduction: The Apple Watch valuably records event-based electrocardiograms (iECG) in children, as shown in recent studies by Paech et al. In contrast to adults, though, the automatic heart rhythm classification of the Apple Watch did not provide satisfactory results in children. Therefore, ECG analysis is limited to interpretation by a pediatric cardiologist. To surmount this difficulty, an artificial intelligence (AI) based algorithm for the automatic interpretation of pediatric Apple Watch iECGs was developed in this study. Methods: A first AI-based algorithm was designed and trained based on prerecorded and manually classified i.e., labeled iECGs. Afterward the algorithm was evaluated in a prospectively recruited cohort of children at the Leipzig Heart Center. iECG evaluation by the algorithm was compared to the 12-lead-ECG evaluation by a pediatric cardiologist (gold standard). The outcomes were then used to calculate the sensitivity and specificity of the Apple Software and the self-developed AI. Results: The main features of the newly developed AI algorithm and the rapid development cycle are presented. Forty-eight pediatric patients were enrolled in this study. The AI reached a specificity of 96.7% and a sensitivity of 66.7% for classifying a normal sinus rhythm. Conclusion: The current study presents a first AI-based algorithm for the automatic heart rhythm classification of pediatric iECGs, and therefore provides the basis for further development of the AI-based iECG analysis in children as soon as more training data are available. More training in the AI algorithm is inevitable to enable the AI-based iECG analysis to work as a medical tool in complex patients.

An extensive comparison of quantitative trait Loci mapping methods.

BACKGROUND: The choices of study design and statistical approach for mapping a quantitative trait (QT) are of great importance. Larger sibships and a study design based upon phenotypically extreme siblings can be expected to have a greater statistical power. On the other hand, selected samples and/or deviation from normality can influence the robustness and power. Unfortunately, the effects of violation of multivariate normality assumptions and/or selected samples are only known for a limited number of methods. Some recommendations are available in the literature, but an extensive comparison of robustness and power under several different conditions is lacking. METHODS: We compared eight freely available and commonly applied QT mapping methods in a Monte-Carlo simulation study under 36 different models and study designs (three genetic models, three selection schemes, two family structures and the possible effect of deviation from normality). RESULTS: Empirical type I error fractions and empirical power are presented and explained as a whole and for each method separately, followed by a thorough discussion. CONCLUSIONS: The results from this extensive comparison could serve as a valuable source for the choice of the study design and the statistical approach for mapping a QT.

Single nucleotide polymorphisms in Brahman steers and their association with carcass and tenderness traits.

Data from purebred Brahman steers (N = 467) were used to study the association of single nucleotide polymorphisms (SNP) with carcass traits and measures of tenderness. Fall weaned calves were grazed and fed in a subtropical environment and then harvested for processing in a commercial facility. Carcass data were recorded 24 h postmortem. Muscle samples and primal ribs were obtained to measure calpastatin activity and shear force. DNA was used to determine genotypes of thyroglobulin (TG5), calpastatin (CAST) and mu-calpain (CAPN 316 and CAPN 4751) SNP. Minor allele frequencies for CAST, CAPN 316 and CAPN 4751 were 0.342, 0.031, and 0.051, respectively. CAST genotypes were associated with calpastatin enzyme activity (P < 0.01) and shear force of steaks aged for 14-day postmortem (P < 0.05). CAPN 316 genotypes were also associated with variation in shear force of steaks aged for 14 days (P < 0.05). CAPN 4751 genotypes approached significance for association with shear force of steaks after 7 and 14 days (P < 0.08). Genotypes for TG5 were non-polymorphic (i.e., minor allele frequency = 0.004) and omitted from further analyses. Neither CAST nor CAPN SNP was associated with variation in other carcass traits.

[Desmopressin testing in children with von Willebrand syndrome in haemostaseologic centers of Saxonia, Saxonia-Anhalt and Thuringia]. / Desmopressin-Tests bei Kindern mit von-Willebrand-Syndrom in den Gerinnungszentren Sachsens, Sachsen-Anhalts und Thüringens.

The influence of desmopressin on hemostasis is mediated by the release of von Willebrand factor and of coagulation factor VIII from vascular endothelium. The necessity of testing desmopressin effectiveness on hemostasis is a matter of controversy and the performance of the test is not yet standardized. For this reason the desmopressin tests in 114 children with von Willebrand syndrome (type 1, n=98; type 2A, n=12; type 2M, n=2; type 2N, n=2) carried out in 7 paediatric haemostaseologic centers were retrospectively analyzed. The effectiveness of desmopressin was assessed using defined response criteria. As expected, the test performance showed a wide variation among the centers. In 99 children desmopressin was given intravenously as a short infusion at a dosage ranging from 0.25 to 0.41 microg/kg and in 15 intranasally at an absolute dose of 40 to 300 microg. The points of time for blood taking after desmopressin application ranged from 0.5 to 12 h. The absent desmopressin response in 7 patients (6%) and the partial response in 15 indicate the necessity of testing desmopressin effectiveness before the first therapeutic use. The application of desmopressin was well tolerated by the patients.

Gate-controlled quantum dots and superconductivity in planar germanium.

Superconductors and semiconductors are crucial platforms in the field of quantum computing. They can be combined to hybrids, bringing together physical properties that enable the discovery of new emergent phenomena and provide novel strategies for quantum control. The involved semiconductor materials, however, suffer from disorder, hyperfine interactions or lack of planar technology. Here we realise an approach that overcomes these issues altogether and integrate gate-defined quantum dots and superconductivity into germanium heterostructures. In our system, heavy holes with mobilities exceeding 500,000 cm2 (Vs)-1 are confined in shallow quantum wells that are directly contacted by annealed aluminium leads. We observe proximity-induced superconductivity in the quantum well and demonstrate electric gate-control of the supercurrent. Germanium therefore has great promise for fast and coherent quantum hardware and, being compatible with standard manufacturing, could become a leading material for quantum information processing.

ATSAS 2.8: a comprehensive data analysis suite for small-angle scattering from macromolecular solutions.

ATSAS is a comprehensive software suite for the analysis of small-angle scattering data from dilute solutions of biological macromolecules or nanoparticles. It contains applications for primary data processing and assessment, ab initio bead modelling, and model validation, as well as methods for the analysis of flexibility and mixtures. In addition, approaches are supported that utilize information from X-ray crystallography, nuclear magnetic resonance spectroscopy or atomistic homology modelling to construct hybrid models based on the scattering data. This article summarizes the progress made during the 2.5-2.8 ATSAS release series and highlights the latest developments. These include AMBIMETER, an assessment of the reconstruction ambiguity of experimental data; DATCLASS, a multiclass shape classification based on experimental data; SASRES, for estimating the resolution of ab initio model reconstructions; CHROMIXS, a convenient interface to analyse in-line size exclusion chromatography data; SHANUM, to evaluate the useful angular range in measured data; SREFLEX, to refine available high-resolution models using normal mode analysis; SUPALM for a rapid superposition of low- and high-resolution models; and SASPy, the ATSAS plugin for interactive modelling in PyMOL. All these features and other improvements are included in the ATSAS release 2.8, freely available for academic users from https://www.embl-hamburg.de/biosaxs/software.html.

Evaluation of DNA polymorphisms involving growth hormone relative to growth and carcass characteristics in Brahman steers.

Associations of DNA polymorphisms in growth hormone (GH) relative to growth and carcass characteristics in growing Brahman steers (N = 324 from 68 sires) were evaluated. Polymorphisms were an Msp-I RFLP and a leucine/valine SNP in the GH gene as well as a Hinf-I RFLP and a histidine/arginine SNP in transcriptional regulators of the GH gene, Pit-1 and Prop-1. Genotypic frequencies of the GH SNP, Pit-1 RFLP, and Prop-1 SNP were greater than 88% for one of the bi-allelic homozygous genotypes. Genotypic frequencies for the GH Msp-I RFLP genotypes were more evenly distributed with frequencies of 0.43, 0.42, and 0.15 for the genotypes of +/+, +/-, and -/-, respectively. Mixed model analyses of growth and carcass traits with genotype and contemporary group serving as fixed effects and sire fitted as a random effect suggested that sire was a significant source of variation (P < 0.05) in average daily gain, carcass yield, and marbling score. However, measures of growth and carcass traits were similar across GH Msp-I genotypes as steers were slaughtered when fat thickness was estimated to be approximately 1.0 cm. These polymorphisms within the GH gene and/or its transcriptional regulators do not appear to be informative predictors of growth and carcass characteristics in Brahman steers. This is partly due to the high level of homozygosity of genotypes. These findings do not eliminate the potential importance of these polymorphisms as predictors of growth and carcass traits in Bos taurus or Bos taurus x Bos indicus composite cattle.

Prognostic relevance of p53 alterations and Mib-1 proliferation index in subgroups of primary liposarcomas.

For prognostic analyses of p53 alterations (p53 gene mutations + p53 immunopositivity) and Mib-1 proliferation index, we investigated 42 primary malignant lipomatous tumors for which complete clinical data and a long follow-up were available. p53 gene mutations were investigated by PCR-single strand conformation polymorphism-sequencing analysis, and immunohistochemistry was used to determine p53 protein expression and Mib-1 proliferation index. We found a mutation frequency of 14.3%. Nine liposarcomas (21%) were p53 immunopositive, and 11 (26.2%) had at least one p53 alteration. In myxoid liposarcomas, p53 alterations are not relevant to the presence or absence of round cell components. Pleomorphic liposarcomas showed a significantly higher proliferation index and more p53 alterations than myxoid or well-differentiated variants (P<0.001). When the Cox's regression analysis tumors of grade III histology (P = 0.005) was performed, the pleomorphic subtype (P = 0.016) and liposarcomas of retroperitoneal localization (P = 0.015) showed a significantly poorer prognosis. Moreover, we found that p53 alterations and high proliferation index correlated significantly with reduced overall survival. Their prognostic value seemed to be higher in myxoid than in pleomorphic liposarcomas. The metastasis-free survival was reduced in patients who had liposarcomas with p53 alterations (P = 0.171) or elevated proliferation index (P<0.016), reflecting a more aggressive behavior. In conclusion, the determination of p53 alterations and/or Mib-1 proliferation index is useful for assessing the prognosis of patients with liposarcomas and may especially be helpful in dividing different prognostic groups for patients with myxoid variants.

Prognostic significance of p53 gene mutations and p53 protein expression in synovial sarcomas.

Alterations to p53 seem to be of prognostic significance in soft tissue sarcomas, but their significance for synovial sarcomas has not been studied. We analysed 34 synovial sarcomas in 19 patients for p53 alterations (p53 gene mutations + p53 immunopositivity) and examined this factor for its prognostic value in a group of 15 primary tumours. DNA was prepared from paraffin-embedded tumour material by a modified proteinase K/phenol/chloroform extraction. p53 gene mutations of exons 5-8 were analysed by the PCR-SSCP-sequencing method. p53 protein expression was evaluated by immunohistochemistry using the murine monoclonal antibody DO1. We found two missense mutations (5.9%) and ten p53 immunopositive cases (29.4%). Both tumours with p53 mutations showed p53 protein expression. There was no significant correlation between p53 alteration and histological subtype, age, sex, or tumour size. The 5-year survival rate was 24.1%. Overall survival was significantly reduced in patients having synovial sarcomas with p53 alterations (P<0.001). In the multivariate Cox's analysis, only p53 alterations (P=0.032) and tumour size (P=0.023) emerged as independent prognostic factors. We suggest that p53 alterations may be a useful prognostic indicator in synovial sarcomas, allowing rational clinical treatment and follow-up.

Ultrasonographic assessment of Schistosoma mansoni and S haematobium morbidity in Zimbabwean schoolchildren.

Ultrasound examinations for Schistosoma haematobium - and S. mansoni-related morbidity were done in 174 schoolchildren from a subsistence farming community in southern Zimbabwe. The examinations were done according to the standardized protocol elaborated by the Cairo Working Group (the Cairo classification) and the Managil classification. Forty-six percent of the children had grade I periportal thickening (PPT) on ultrasound according to the Cairo classification, but none had grade II or higher. The significance of grade I PPT in the Cairo classification is questionable, since there were no differences between those without and those with grade I PPT with respect to intensity of S. mansoni infection or liver size. The prevalence of grade I PPT according to the Managil classification was 10%, and no association between the two classifications was seen. In multiple regression analysis, S. mansoni egg output was found to be a significant predictor of liver size, when controlling for height and sex. An interaction between S. haematobium and S. mansoni infection is suggested because the positive relationship between S. mansoni and liver size was seen in the presence but not in the absence of S. haematobium infection.

Lack of ultrasonographic evidence for severe hepatosplenic morbidity in schistosomiasis mansoni in Mali.

The inhabitants of four villages endemic for Schistosoma mansoni in central Mali (n = 1,106 of both sexes, age range 2-80 years) and of two nonendemic villages in another part of the country were examined parasitologically and ultrasonographically to establish the prevalence of periportal liver fibrosis (PF) and other features of hepatosplenic schistosomiasis. The prevalence of S. mansoni infection ranged from 36% to 93% in the endemic villages. A severe infection (> 400 eggs/g of stool) was found in 16% of the infected individuals. No case of grade III PF (echogenic bands usually > 10 mm in diameter around the central part and major branches of the portal vein and streak-like fibrous bands that extended into the periphery of the liver) and only eight cases of grade II PF (echogenic bands usually > 10 mm in diameter around the central part and major branches of the portal vein) were found; no other signs of severe hepatosplenic disease were encountered. However, grade I PF (echogenic bands usually > 4 mm in diameter that were best visible in the area of the portal vein bifurcation and gall bladder neck) was detected in 21% of all individuals, mainly in adults. In the nonendemic villages, the prevalence of grade I PF in adults was 9%. Generally, there was no significant correlation between the grade of PF and S. mansoni egg output. In one village with a high endemicity level, however, the prevalence of grade PF I increased with the intensity of infection. Morphometric data revealed no significant influence of S. mansoni infection on portal vein stem diameter and spleen size.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonographical investigation of periportal fibrosis in children with Schistosoma mansoni infection: reversibility of morbidity seven months after treatment with praziquantel.

Five hundred thirty six Sudanese schoolchildren with Schistosoma mansoni infection were treated at random with either 20 mg or 40 mg/kg praziquantel. Seven months later 420 children could be reinvestigated by ultrasonography. Reduction of egg excretion and reversibility of sonographically-proven periportal fibrosis (PF) was not significantly different in the two groups. Schistosoma mansoni-induced PF grade II decreased from 22.9% to 6.7% and grade III from 5.2% to 1.6%. An increased prevalence of PF grade I, from 10% to 29.8% of the investigated patients, was observed. This increase was caused partly by a downshifting of patients who had PF II (n = 45) and PF III (n = 8) before therapy, but also by patients who developed PF I in the seven months after therapy (n = 56). The overall percentage of patients with PF before and after treatment was 38.1%. Of 420 children, 17.4% increased in their PF grade, 55% remained at the same level and 27.6% improved. Children younger than 11 years of age had a higher rate of complete reversibility than older ones. The percentage of patients with hepatomegaly decreased significantly (11.6% to 6.9%; p = 0.001). The rate of splenomegaly remained unchanged. It was concluded that within seven months therapy with praziquantel resulted in a considerable qualitative improvement of PF in Sudanese schoolchildren with S. mansoni infection.

Sonomorphological abnormalities in Sudanese children with Schistosoma mansoni infection: a proposed staging-system for field diagnosis of periportal fibrosis.

For the purpose of staging sonographical abnormalities induced by Schistosoma mansoni infection in childhood, 536 patients aged 6-15 years underwent extensive sonographical examination. Specific findings of periportal fibrosis were classified in 3 grades and occurred in study patients but not in controls (n = 60). Grade I consisted of echogenic bands usually with a diameter greater than 4 mm that were best visible in the area of the portal vein bifurcation and gallbladder neck. Frequently a continuous U-shaped echogenic structure extended from the left portal branch to the gallbladder bed. Grade II was characterized by echogenic bands usually greater than 10 mm in diameter around the central part and major branches of the portal vein. In addition to features common to grade II, grade III included streak-like fibrous bands that were not confined to portal vein lumina but extended into the periphery of the liver. Sonographical abnormalities encountered in children with S. mansoni infection differed significantly from those in adults.