The physical implementation of quantum information processing relies on individual modules-qubits-and operations that modify such modules either individually or in groups-quantum gates. Two examples ...of gates that entangle pairs of qubits are the controlled NOT-gate (CNOT) gate, which flips the state of one qubit depending on the state of another, and the gate that brings a two-qubit product state into a superposition involving partially swapping the qubit states. Here we show that through supramolecular chemistry a single simple module, molecular {Cr7Ni} rings, which act as the qubits, can be assembled into structures suitable for either the CNOT or gate by choice of linker, and we characterize these structures by electron spin resonance spectroscopy. We introduce two schemes for implementing such gates with these supramolecular assemblies and perform detailed simulations, based on the measured parameters including decoherence, to demonstrate how the gates would operate.
Fetal and adult hematopoietic stem cells (HSCs) have distinct proliferation rates, lineage biases, gene expression profiles, and gene dependencies. Although these differences are widely recognized, ...it is not clear how the transition from fetal to adult identity is coordinated. Here we show that murine HSCs and committed hematopoietic progenitor cells (HPCs) undergo a gradual, rather than precipitous, transition from fetal to adult transcriptional states. The transition begins prior to birth and is punctuated by a late prenatal spike in type I interferon signaling that promotes perinatal HPC expansion and sensitizes progenitors to the leukemogenic FLT3ITD mutation. Most other changes in gene expression and enhancer activation are imprecisely timed and poorly coordinated. Thus, heterochronic enhancer elements, and their associated transcripts, are activated independently of one another rather than as part of a robust network. This simplifies the regulatory programs that guide neonatal HSC/HPC ontogeny, but it creates heterogeneity within these populations.
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•Murine HSCs and HPCs transition gradually from fetal to adult transcriptional states•Regulatory networks are uncoordinated, causing extensive neonatal HSC heterogeneity•Fetal-to-neonatal transitions coincide with a late gestational type I interferon pulse•The pulse promotes HPC expansion and sensitivity to leukemogenic FLT3-ITD signaling
Li et al. have used single-cell RNA-seq to understand how hematopoietic stem cells transition from fetal to adult states. They show that the shift is gradual and uncoordinated, but it begins with a precisely timed interferon pulse during late fetal development. Neonatal interferon modulates normal hematopoiesis and leukemia initiation.
Quantum information processing (QIP) could revolutionize how we simulate and understand quantum systems. Any QIP scheme requires both individual units (qubits) that have long phase memories and ...switchable units that can be placed between the qubits. Here, we describe supramolecular systems where {Cr7Ni} rings are used as qubits, linked by redox-switchable {Ru2M} oxo-centered triangles (M = Zn, Ni, or Co). The supramolecular assemblies have been structurally characterized and involve two {Cr7Ni} rings bound to {Ru2M} triangles through iso-nicotinate ligands. Detailed physical studies, including electrochemistry and electron paramagnetic resonance spectroscopy, show that when M = Co, the supramolecular assembly has the physical characteristics needed to implement the √iSWAP gate, which is an important entangling two-qubit gate. Detailed simulations show that the fidelity of this gate is potentially very high and depends on the phase memory time of the {Cr7Ni} qubits but not the {Ru2Co} switch.
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One of the greatest potential advantages of quantum information processing (QIP) over classic computing is the efficient simulation of the behavior of quantum systems. Many physical systems have been studied for QIP, and each has advantages and disadvantages. The use of supramolecular chemistry for QIP allows us to design architectures and interactions that are entirely controllable through chemistry. If such schemes could be made to work, the implications are a far better understanding of quantum systems. In addition, certain computational tasks such as searching unsorted directories or factoring large numbers into primes could be performed much more quickly.
•A family of switchable-exchange molecular double qubits has been obtained•Detailed simulations show that qubit-qubit interaction can be effectively switched•Many quantum gates can be concatenated for implementing quantum simulation algorithms
Winpenny and colleagues describe supramolecular systems where {Cr7Ni} rings are used as qubits, linked by redox-switchable {Ru2M} oxo-centered triangles (M = Zn, Ni, or Co). When M = Co, the molecular-based double-qubit assembly has the physical characteristics needed to implement the √iSWAP gate. The authors propose a local control of the qubit-qubit interaction on an individual supramolecular dimer, achieved by an STM tip. Detailed simulations show that many quantum gates can be concatenated for implementation of quantum simulation algorithms.
Ru2Mn(O)(O2CtBu)6(py)3 has an S=5/2 ground state with a very large zero‐field splitting (ZFS) of D=2.9 cm−1, as characterized by EPR spectroscopy at 4–330 GHz. This is far too large to be due to the ...MnII ion (D <0.2 cm−1), as shown from the {Fe2Mn} analogue, but can be modeled by antisymmetric exchange effects.
Zeroing in: By using RuIII2MnII(O)(tBuCO2)6(py)3 as an example, antisymmetric exchange effects have been shown to lead to very large spin ground‐state zero‐field splittings in polymetallic complexes. The zero‐field splitting of the S=5/2 ground state of the heterometallic oxo‐centered triangle has been measured as D=3 cm−1, an order of magnitude larger than found for the {Fe2Mn} analogue.
Ru2Mn(O)(O2CtBu)6(py)3 has an S=5/2 ground state with a very large zero-field splitting (ZFS) of D=2.9cm(-1), as characterized by EPR spectroscopy at 4-330GHz. This is far too large to be due to ...the Mn(II) ion (D <0.2cm(-1)), as shown from the {Fe2Mn} analogue, but can be modeled by antisymmetric exchange effects.
Ru2Mn(O)(O2CtBu)6(py)3 has an S=5/2 ground state with a very large zero‐field splitting (ZFS) of D=2.9 cm−1, as characterized by EPR spectroscopy at 4–330 GHz. This is far too large to be due to the ...MnII ion (D <0.2 cm−1), as shown from the {Fe2Mn} analogue, but can be modeled by antisymmetric exchange effects.
Null‐Problem: Am Beispiel von RuIII2MnII(O)(tBuCO2)6(py)3 wurde gezeigt, dass antisymmetrische Austauscheffekte zu sehr großen Nullfeldaufspaltungen des Spin‐Grundzustands von Mehrkernkomplexen führen. Die Nullfeldaufspaltung des S=5/2‐Grundzustands dieses Heterometalldreiecks mit zentralem Oxoligand liegt mit D=3 cm−1 um eine Größenordnung über derjenigen des {Fe2Mn}‐Analogons.
Objective Placental growth factor and soluble Fms-like tyrosine kinase-1 may be potential diagnostic markers of preeclampsia. We compared performances of 2 immunoassays, the Triage placental growth ...factor assay and the Elecsys soluble Fms-like tyrosine kinase-1/placental growth factor ratio in diagnosing preeclampsia. Study Design A single site, case-control study of 44 patients with preeclampsia and 84 matched normal pregnant controls. Samples were collected at the time of diagnosis. Assays were performed according to product inserts. Results Both assays had optimal performance in diagnosing early-onset preeclampsia with area under the receiver operating characteristic curves of 0.99 (Triage: 100% sensitivity, 96% specificity; Elecsys: 64% sensitivity, 100% specificity for early-onset preeclampsia). Reassignment of the Elecsys cutoff for a positive test based on receiver operating characteristic curves increased sensitivity to 92%. Conclusion Using product insert cutoffs, Triage appears to have greater sensitivity at only a small reduction in specificity compared with Elecsys in the diagnosis of early-onset preeclampsia. A different cutoff may improve Elecsys sensitivity.
Objective We investigated whether decreased concentrations of placental growth factor (PlGF) in maternal circulation differentiated placental intrauterine growth restriction (IUGR) from ...constitutionally small fetuses. Excluding congenital syndromes, infection, and aneuploidy, we assumed IUGR with an abnormal placental pathology to be of placental origin. Study Design The study design included a single site, case-control study of 16 cases (9 placental IUGR, 7 constitutionally small) and 79 normal controls with singleton pregnancies. Plasma PlGF was measured by Triage PlGF immunoassay according to the product insert. A positive PlGF test was defined as a concentration less than the fifth percentile for gestational age for normal pregnancy. Results A positive PlGF test was found in 9 of 9 placental IUGR cases, 1 of 7 constitutionally small fetuses, and 4 of 79 controls ( P < .0001). PlGF identified placental IUGR from constitutionally small fetuses with 100% sensitivity and 86% specificity ( P = .0009). Conclusion These preliminary data suggest PlGF may identify placental IUGR antenatally.
The current study used a mixed-methods approach to investigate the positive and negative aspects of Internet use for sexual health information among lesbian, gay, bisexual, and transgender (LGBT) ...young people. A diverse community sample of 32 LGBT young people (aged 16-24 years) completed qualitative interviews focusing on how, where, and when LGBT young people use the Internet for sexual health information. Results indicate that although many participants seek facts and statistics about sexually transmitted infections (STIs) and HIV online, few conduct searches about broader aspects of sexual health. Participants reported that fear about becoming infected with STIs/HIV is a common motivator of searches and noted a number of reasons for not using online sexual health information, including stigma associated with being observed accessing LGBT or HIV information. Together, the results revealed not only significant interest in online sexual health information but also concerns about the perceived limitations of this promising method of sexual health promotion.
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