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Spin qubits defined by valence band hole states are attractive for quantum information processing due to their inherent coupling to electric fields, enabling fast and scalable qubit control. Heavy holes in germanium are particularly promising, with recent demonstrations of fast and high-fidelity qubit operations. However, the mechanisms and anisotropies that underlie qubit driving and decoherence remain mostly unclear. Here we report the highly anisotropic heavy-hole g-tensor and its dependence on electric fields, revealing how qubit driving and decoherence originate from electric modulations of the g-tensor. Furthermore, we confirm the predicted Ising-type hyperfine interaction and show that qubit coherence is ultimately limited by 1/f charge noise, where f is the frequency. Finally, operating the qubit at low magnetic field, we measure a dephasing time of T 2 * = 17.6 µs, maintaining single-qubit gate fidelities well above 99% even at elevated temperatures of T > 1 K. This understanding of qubit driving and decoherence mechanisms is key towards realizing scalable and highly coherent hole qubit arrays.
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AIM OF THE STUDY: Notch signaling plays important roles in maintaining intestinal epithelial homeostasis. When Notch signaling is blocked, proliferation ceases and epithelial cells become secretory. The purpose of the present study was to evaluate the role of Notch signaling pathway following intestinal ischemia-reperfusion (IR) injury in a rat model. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomly divided into four experimental groups: Sham-24 and Sham-48 rats underwent laparotomy and were killed 24 or 48 h later, respectively; IR-24 and IR-48 rats underwent occlusion of SMA and portal vein for 30 min followed by 24 or 48 h of reperfusion, respectively. Enterocyte proliferation and enterocyte apoptosis were determined at killing. Notch-related gene and protein expression were determined using Real Time PCR, Western blotting and immunohistochemistry 48 h followed IR. MAIN RESULTS: IR-48 rats demonstrated significantly increased rates of cell proliferation and increased cell apoptosis in both jejunum and ileum compared to Sham rats. IR-48 rats exhibited a significant decrease in Notch-1 protein expression (Western blot) that was coincided with a significant decrease in the number of Notch-1 positive cells (immunohistochemistry) in jejunum (35% decrease, p < 0.05) and ileum (twofold decrease, p < 0.05) as well as Hes-1 positive cells in jejunum (28% decrease, p < 0.05) and ileum (31% decrease, p < 0.05) compared to Sham-48 rats. CONCLUSIONS: Forty-eight hours following intestinal IR in rats, accelerated cell turnover was associated by inhibited Notch signaling pathway. Intestinal stem cells differentiation toward secretory progenitors rather than differentiation toward absorptive cells is important at this phase of intestinal recovery.
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Apoptose/fisiologia , Proliferação de Células/fisiologia , Enteropatias/fisiopatologia , Mucosa Intestinal/fisiopatologia , Traumatismo por Reperfusão/fisiopatologia , Transdução de Sinais/fisiologia , Animais , Western Blotting , Modelos Animais de Doenças , Enterócitos/metabolismo , Imuno-Histoquímica , Mucosa Intestinal/metabolismo , Masculino , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/metabolismo , TempoRESUMO
At submonolayer coverage, Mn forms atomic wires on the Si(001) surface oriented perpendicular to the underlying Si dimer rows. While many other elements form symmetric dimer wires at room temperature, we show that Mn wires have an asymmetric appearance and pin the Si dimers nearby. We find that an atomic configuration with a Mn trimer unit cell can explain these observations as due to the interplay between the Si dimer buckling phase near the wire and the orientation of the Mn trimer. We study the resulting four wire configurations in detail using high-resolution scanning tunneling microscopy (STM) imaging and compare our findings with the STM images simulated by density functional theory.
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Recent experiments have suggested that superconductivity in metallic nanowires can be suppressed by the application of modest gate voltages. The source of this gate action has been debated and either attributed to an electric-field effect or to small leakage currents. Here we show that the suppression of superconductivity in titanium nitride nanowires on silicon substrates does not depend on the presence or absence of an electric field at the nanowire, but requires a current of high-energy electrons. The suppression is most efficient when electrons are injected into the nanowire, but similar results are obtained when electrons are passed between two remote electrodes. This is explained by the decay of high-energy electrons into phonons, which propagate through the substrate and affect superconductivity in the nanowire by generating quasiparticles. By studying the switching probability distribution of the nanowire, we also show that high-energy electron emission leads to a much broader phonon energy distribution compared with the case where superconductivity is suppressed by Joule heating near the nanowire.
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Recent experiments with metallic nanowires devices seem to indicate that superconductivity can be controlled by the application of electric fields. In such experiments, critical currents are tuned and eventually suppressed by relatively small voltages applied to nearby gate electrodes, at odds with current understanding of electrostatic screening in metals. We investigate the impact of gate voltages on superconductivity in similar metal nanowires. Varying materials and device geometries, we study the physical mechanism behind the quench of superconductivity. We demonstrate that the transition from superconducting to resistive state can be understood in detail by tunneling of high-energy electrons from the gate contact to the nanowire, resulting in quasiparticle generation and, at sufficiently large currents, heating. Onset of critical current suppression occurs below gate currents of 100fA, which are challenging to detect in typical experiments.
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We describe design, implementation, and performance of an ultra-high vacuum (UHV) package for superconducting qubit chips or other surface sensitive quantum devices. The UHV loading procedure allows for annealing, ultra-violet light irradiation, ion milling, and surface passivation of quantum devices before sealing them into a measurement package. The package retains vacuum during the transfer to cryogenic temperatures by active pumping with a titanium getter layer. We characterize the treatment capabilities of the system and present measurements of flux tunable qubits with an average T1 = 84 µs and T2 echo=134µs after vacuum-loading these samples into a bottom loading dilution refrigerator in the UHV-package.
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Strong radial confinement in semiconductor nanowires leads to modified electronic and phononic energy spectra. We analyze the current response to the interplay between quantum confinement effects of the electron and phonon systems in a gate-defined double quantum dot in a semiconductor nanowire. We show that current spectroscopy of inelastic transitions between the two quantum dots can be used as an experimental probe of the confined phonon environment. The resulting discrete peak structure in the measurements is explained by theoretical modeling of the confined phonon mode spectrum, where the piezoelectric coupling is of crucial importance.
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A hemodialysis patient suffered from circulation failure due to a low output syndrome caused by a hyperkalemia (9.9 micromol/l) with typical ecg signs. An emergency hemodialysis was started. After 2 h ecg signs of hypokalemia (2.1 micromol/l) were detectable. Hemodialysis was stopped. 2 h later, serum potassium rose to 6.2 micromol/l. An obturation of the aorta and the inferior caval vein with perfusion through collateral vessels of the lower body side was obvious, resulting into a faster electrolyte correction in the upper and a delayed correction in the lower body side with a rebound in the upper compartment. Dialysis time and dialysate potassium (4.0 micromol/l) were increased. Furthermore no potassium problems occurred.
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Hiperpotassemia/etiologia , Síndrome de Leriche/complicações , Potássio/sangue , Diálise Renal/efeitos adversos , Aortografia/métodos , Eletrocardiografia , Tratamento de Emergência , Humanos , Hiperpotassemia/sangue , Hipopotassemia/sangue , Hipopotassemia/etiologia , Cinética , Síndrome de Leriche/sangue , Síndrome de Leriche/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Tomografia Computadorizada por Raios X , Resultado do TratamentoRESUMO
Microarray-based gene expression profiling (GEP) was used to study how stroma modulates the survival of CLL cells in an in vitro coculture model employing the murine fibroblast cell line M2-10B4. CLL cells cultured in direct contact with the stromal layer (STR) showed a significantly better survival than cells cultured in transwell (TW) inserts above the M2-10B4 cells. STR as compared to TW conditions induced a significant up-regulation of PI3K/NF-kappaB pro-survival pathway genes and mediated a pro-angiogenetic switch in the CLL cells by up-regulation of vascular endothelial growth factor (VEGF) and osteopontin (OPN) and down-regulation of the anti-angiogenetic molecule thrombospondin-1 (TSP-1).
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Proteínas Angiogênicas/metabolismo , Fibroblastos/fisiologia , Leucemia Linfocítica Crônica de Células B/metabolismo , NF-kappa B/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Animais , Apoptose , Células da Medula Óssea/citologia , Comunicação Celular , Ciclo Celular/genética , Linhagem Celular , Técnicas de Cocultura , Reparo do DNA/genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Leucemia Linfocítica Crônica de Células B/enzimologia , Leucemia Linfocítica Crônica de Células B/genética , Camundongos , Fenótipo , Transdução de Sinais/genética , Células Estromais/fisiologia , Células Tumorais CultivadasRESUMO
B-cell chronic lymphocytic leukaemia (B-CLL) is a heterogenous disease with a highly variable clinical course and analysis of zeta-associated protein 70 (ZAP-70) and CD38 expression on B-CLL cells allowed for identification of patients with good (ZAP-70-CD38-) and poor (ZAP-70+CD38+) prognosis. DNA microarray technology was employed to compare eight ZAP-70+CD38+ with eight ZAP-70-CD38- B-CLL cases. The expression of 358 genes differed significantly between the two subgroups, including genes involved in B-cell receptor signaling, angiogenesis and lymphomagenesis. Three of these genes, that is, immune receptor translocation-associated protein 4 (IRTA4)/Fc receptor homologue 2 (FcRH2), angiopoietin 2 (ANGPT2) and Pim2 were selected for further validating studies in a cohort of 94 B-CLL patients. IRTA4/FcRH2 expression as detected by flow cytometry was significantly lower in the poor prognosis subgroup as compared to ZAP-70-CD38- B-CLL cells. In healthy individuals, IRTA4/FcRH2 protein expression was associated with a CD19+CD27+ memory cell phenotype. ANGPT2 plasma concentrations were twofold higher in the poor prognosis subgroup (P<0.05). Pim2 was significantly overexpressed in poor prognosis cases and Binet stage C. Disease progression may be related to proangiogenic processes and strong Pim2 expression.
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ADP-Ribosil Ciclase 1/genética , Regulação Leucêmica da Expressão Gênica , Leucemia Linfocítica Crônica de Células B/genética , Glicoproteínas de Membrana/genética , Proteína-Tirosina Quinase ZAP-70/genética , ADP-Ribosil Ciclase 1/metabolismo , Idoso , Idoso de 80 Anos ou mais , Angiopoietina-2/genética , Angiopoietina-2/metabolismo , Linfócitos B/patologia , Linfócitos B/fisiologia , Diferenciação Celular , Estudos de Coortes , Feminino , Citometria de Fluxo , Humanos , Leucemia Linfocítica Crônica de Células B/classificação , Leucemia Linfocítica Crônica de Células B/epidemiologia , Masculino , Glicoproteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Neovascularização Patológica/genética , Análise de Sequência com Séries de Oligonucleotídeos , Prognóstico , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcr/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Fatores de Risco , Transdução de Sinais/genética , Proteína-Tirosina Quinase ZAP-70/metabolismoRESUMO
B-cell chronic lymphocytic leukemia (B-CLL) is a heterogenous disease with a highly variable clinical course. Recent studies have shown that expression of the protein tyrosine kinase ZAP-70 may serve as a prognostic marker in B-CLL. Employing a semiquantitative RT-PCR assay, we examined purified leukemia B cells of 39 CLL patients for the expression of ZAP-70 mRNA transcripts. Significant ZAP-70 mRNA levels exceeding those found in control samples with 5% T cells were detected in 36% of the CLL cases. Patients in the ZAP-70 positive cohort were characterized by an unfavorable clinical course with a significantly shorter progression-free survival as compared to the ZAP-70-negative patients (64%). These results were confirmed by flow-cytometric analysis of the ZAP-70 protein, and expanded to a larger patient cohort (n=67). A combined statistical analysis of 79 patients showed that the two patient subgroups also differed with regard to overall survival and a panel of known clinical prognostic factors including LDH, thymidine kinase serum levels and expression of the CD38 surface antigen by the leukemic cell clone. The level of ZAP-70 expression did not change over time in the majority of patients where sequential samples were available for analysis.
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Biomarcadores Tumorais/genética , Leucemia Linfocítica Crônica de Células B/diagnóstico , Leucemia Linfocítica Crônica de Células B/genética , Proteínas Tirosina Quinases/genética , ADP-Ribosil Ciclase/metabolismo , ADP-Ribosil Ciclase 1 , Antígenos CD/metabolismo , Antineoplásicos/uso terapêutico , Células Clonais , Citometria de Fluxo , Regulação Enzimológica da Expressão Gênica , Regulação Leucêmica da Expressão Gênica , Humanos , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Leucemia Linfocítica Crônica de Células B/mortalidade , Glicoproteínas de Membrana , Prognóstico , Estudos Retrospectivos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Risco , Timidina Quinase/sangue , Resultado do Tratamento , Proteína-Tirosina Quinase ZAP-70 , Microglobulina beta-2/sangueRESUMO
BACKGROUND: Terminal renal insufficiency is characterized by the need for renal replacement therapy for survival of the patient. In addition to several types of dialysis treatment, successful renal transplantation offers the best form of renal replacement therapy in terms of long-term patient survival and quality of life. METHOD: Living donor renal transplantation offers the best conditions concerning quality of organ transplanted and graft survival. CONCLUSION: The risk of complications associated with renal transplantation are manageable; however, these must be weighed against the potential benefits of successful transplantation.
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Rejeição de Enxerto/etiologia , Falência Renal Crônica/diagnóstico , Falência Renal Crônica/terapia , Transplante de Rim/efeitos adversos , Transplante de Rim/métodos , Doadores Vivos , Alemanha , Rejeição de Enxerto/prevenção & controle , Humanos , Seleção de Pacientes , Qualidade de Vida , Fatores de Risco , Resultado do TratamentoRESUMO
HepatoConsult is a publicly available knowledge-based second opinion and documentation system aiding in the diagnosis of liver diseases. The positive results of a prospective diagnostic evaluation study encouraged its use in clinical routine, although the available hardware infrastructure was not optimal. The comments of the physicians who used the system confirmed the results of the study and showed that the time for data entering is acceptable and the implicit standardization of terminology and documentation is welcome. Suggestions for improvement included the interface to enter data more easily, the scope to be usable for more patients and the additional capability to generate medical reports from the data.
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Inteligência Artificial , Hepatopatias/diagnóstico , Sistemas Computadorizados de Registros Médicos , Encaminhamento e Consulta , Computadores , Documentação , Humanos , SoftwareRESUMO
Members of the Dobrava-Belgrade virus (DOBV) species are hantaviruses carried by different Apodemus mice as reservoir hosts and causing haemorrhagic fever with renal syndrome (HFRS) in humans. In Central Europe, the Kurkino genotype of DOBV, associated with the striped field mouse, Apodemus agrarius, is prevalent. This paper presents the first extensive study of the serological and molecular diagnostics, epidemiology and clinics of DOBV-Kurkino infections in Central Europe. Serum samples from 570 German patients living in the habitat of A. agrarius (north and northeast Germany) and exhibiting febrile disease, were analysed. All samples were tested by ELISA, subsets of samples were also analysed by immunoblot, neutralization assay, and RT-PCR. A group of 86 individuals was confirmed as DOBV-infected. The virus neutralization assay allowed a reliable identification of DOBV antibodies during both acute and convalescent phases of infection. However, differentiation of relevant DOBV genotypes was not possible by neutralization test but required molecular analysis. Whereas DOBV IgM antibodies tend to persist in the infected organism, RNAaemia seems to be short. Nucleotide sequences were amplified from four patients, and their analysis demonstrated infection by DOBV-Kurkino. With respect to the initial results, the high degree of identity of local patient-derived and A. agrarius-derived virus sequences may allow a closer allocation of the geographical place where the human infection occurred. In contrast to moderate/severe HFRS caused by the DOBV genotypes Dobrava or Sochi, all available data showed a mild clinical course of HFRS caused by DOBV-Kurkino infection without lethal outcomes.
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Febre Hemorrágica com Síndrome Renal/imunologia , Febre Hemorrágica com Síndrome Renal/virologia , Orthohantavírus/classificação , Orthohantavírus/genética , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Anticorpos Antivirais/sangue , Criança , Feminino , Genótipo , Alemanha , Orthohantavírus/imunologia , Febre Hemorrágica com Síndrome Renal/epidemiologia , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Filogenia , Adulto JovemRESUMO
Patients with immunodeficiency and patients under immunosuppressive therapy have an increased risk of infectious diseases. Vaccination strategies are needed to protect them from preventable diseases. The underlying disease and severity of the immune impairment may have influence on indications and contra-indications of vaccines. Inactivated vaccines can be administered safely according to the current recommendations of the Permanent Commission on Vaccinations of the Robert-Koch-Institut in Berlin, Germany (STIKO). Depending on the severity of the immune dysfunction, antibody response to vaccinations varies. Where possible, the antibody response following vaccinations should be tested. Previously, attenuated live vaccines were considered to be strictly contra-indicated in immunocompromised patients. Today, the administration of attenuated live vaccines is thought to be possible, depending on the degree and type of immunodeficiency or immunosuppression of the individual.
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Síndromes de Imunodeficiência/complicações , Síndromes de Imunodeficiência/tratamento farmacológico , Imunossupressores/efeitos adversos , Infecções/etiologia , Vacinação , Contraindicações , HumanosRESUMO
HISTORY AND ADMISSION FINDINGS: A 20-year-old woman was admitted to our hospital because of acute renal failure. She was pregnant in the third trimester. She reported on nausea, feeling of sickness, vomiting, abdominal pain and consecutively gross hematuria and sinustachycardia. Under suspicion of premature labour the patient was admitted to an external hospital. An antibiotic therapy with intravenous ampicillin/sulbactam was initiated. Because of acute kidney injury the patient was transferred firstly to the university women's hospital and finally to the department of nephrology. Obesity, the clinical signs of pregnancy, dehydration and small edema of the lower legs were the main medical findings on examination. INVESTIGATIONS: Laboratory tests revealed hyperuricemia, virological tests detected an acute infection with Dobrava-Belgrade virus. The ultrasonography demonstrated a pregnancy in good condition and a dilated (physiological) renal pelvis but otherwise normal renal morphology. DIAGNOSIS, TREATMENT AND COURSE: A Hantavirus associated acute kidney failure due to infection with the Dobrava-Belgrade virus was diagnosed. The course of the acute renal failure was characterised by remission of all symptoms. Intermittent evaluation by an obstetrician and a nephrologist were done to diagnose maternal and/or fetal complications. A renal replacement therapy was not necessary. At the 41st week of gestation a healthy male infant was born. The development of the newborn was age-appropriate. CONCLUSION: Hantavirus infections should be considered in cases of pregnancy-associated acute kidney injury.
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Injúria Renal Aguda/prevenção & controle , Antivirais/uso terapêutico , Infecções por Hantavirus/diagnóstico , Infecções por Hantavirus/tratamento farmacológico , Hiperuricemia/prevenção & controle , Complicações Infecciosas na Gravidez/diagnóstico , Complicações Infecciosas na Gravidez/tratamento farmacológico , Injúria Renal Aguda/diagnóstico , Injúria Renal Aguda/etiologia , Feminino , Infecções por Hantavirus/complicações , Humanos , Hiperuricemia/diagnóstico , Hiperuricemia/etiologia , Gravidez , Terceiro Trimestre da Gravidez , Resultado do Tratamento , Adulto JovemRESUMO
As silicon electronics approaches the atomic scale, interconnects and circuitry become comparable in size to the active device components. Maintaining low electrical resistivity at this scale is challenging because of the presence of conï¬ning surfaces and interfaces. We report on the fabrication of wires in silicon--only one atom tall and four atoms wide--with exceptionally low resistivity (~0.3 milliohm-centimeters) and the current-carrying capabilities of copper. By embedding phosphorus atoms within a silicon crystal with an average spacing of less than 1 nanometer, we achieved a diameter-independent resistivity, which demonstrates ohmic scaling to the atomic limit. Atomistic tight-binding calculations conï¬rm the metallicity of these atomic-scale wires, which pave the way for single-atom device architectures for both classical and quantum information processing.
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Infecções por HIV/prevenção & controle , Prisioneiros , Seringas/provisão & distribuição , Política de Saúde , Humanos , Uso Comum de Agulhas e Seringas/estatística & dados numéricos , Projetos Piloto , Avaliação de Programas e Projetos de Saúde , Abuso de Substâncias por Via Intravenosa/epidemiologia , Suíça/epidemiologiaRESUMO
Nanoscale control of doping profiles in semiconductor devices is becoming of critical importance as channel length and pitch in metal oxide semiconductor field effect transistors (MOSFETs) continue to shrink toward a few nanometers. Scanning tunneling microscope (STM) directed self-assembly of dopants is currently the only proven method for fabricating atomically precise electronic devices in silicon. To date this technology has realized individual components of a complete device with a major obstacle being the ability to electrically gate devices. Here we demonstrate a fully functional multiterminal quantum dot device with integrated donor based in-plane gates epitaxially assembled on a single atomic plane of a silicon (001) surface. We show that such in-plane regions of highly doped silicon can be used to gate nanostructures resulting in highly stable Coulomb blockade (CB) oscillations in a donor-based quantum dot. In particular, we compare the use of these all epitaxial in-plane gates with conventional surface gates and find superior stability of the former. These results show that in the absence of the randomizing influences of interface and surface defects the electronic stability of dots in silicon can be comparable or better than that of quantum dots defined in other material systems. We anticipate our experiments will open the door for controlled scaling of silicon devices toward the single donor limit.
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We investigate tunable hole quantum dots defined by surface gating Ge/Si core-shell nanowire heterostructures. In single level Coulomb-blockade transport measurements at low temperatures spin doublets are found, which become sequentially filled by holes. Magnetotransport measurements allow us to extract a g factor g approximately 2 close to the value of a free spin-1/2 particle in the case of the smallest dot. In less confined quantum dots smaller g factor values are observed. This indicates a lifting of the expected strong spin-orbit interaction effects in the valence band for holes confined in small enough quantum dots. By comparing the excitation spectrum with the addition spectrum we tentatively identify a hole exchange interaction strength chi approximately 130 microeV.