Quantum transducers can transfer quantum information between different systems. Microwave–optical photon conversion is important for future quantum networks to interconnect remote superconducting ...quantum computers with optical fibers. Here, a high‐speed quantum transducer based on a single‐photon emitter in an atomically thin membrane resonator, that can couple single microwave photons to single optical photons, is proposed. The 2D resonator is a freestanding van der Waals heterostructure (which may consist of hexagonal boron nitride, graphene, or other 2D materials) that hosts a quantum emitter. The mechanical vibration (phonon) of the 2D resonator interacts with optical photons by shifting the optical transition frequency of the single‐photon emitter with strain or the Stark effect. The mechanical vibration couples to microwave photons by shifting the resonant frequency of an LC circuit that includes the membrane. Thanks to the small mass of the 2D resonator, both the single‐photon optomechanical coupling strength and the electromechanical coupling strength can reach the strong coupling regime. This provides a way for high‐speed quantum state transfer between a microwave photon, a phonon, and an optical photon.
A high‐speed quantum transducer based on a single‐photon emitter in an atomically thin membrane resonator, which can couple single microwave photons to single optical photons for quantum information applications, is proposed. Thanks to the small mass of the 2D resonator, both the single‐photon optomechanical coupling strength and the electromechanical coupling strength can reach strong coupling regime.
Mineralogical observations, chemical and oxygen–isotope compositions, absolute
207Pb–
206Pb ages and short-lived isotope systematics (
7Be–
7Li,
10Be–
10B,
26Al–
26Mg,
36Cl–
36S,
41Ca–
41K,
53Mn–
...53Cr,
60Fe–
60Ni,
182Hf–
182W) of refractory inclusions Ca,Al-rich inclusions (CAIs) and amoeboid olivine aggregates (AOAs), chondrules and matrices from primitive (unmetamorphosed) chondrites are reviewed in an attempt to test (i) the
x-wind model
vs. the shock-wave model of the origin of chondritic components and (ii) irradiation
vs. stellar origin of short-lived radionuclides. The data reviewed are consistent with an external, stellar origin for most short-lived radionuclides (
7Be,
10Be, and
36Cl are important exceptions) and a shock-wave model for chondrule formation, and provide a sound basis for early Solar System chronology. They are inconsistent with the
x-wind model for the origin of chondritic components and a local, irradiation origin of
26Al,
41Ca, and
53Mn.
10Be is heterogeneously distributed among CAIs, indicating its formation by local irradiation and precluding its use for the early solar system chronology.
41Ca–
41K, and
60Fe–
60Ni systematics are important for understanding the astrophysical setting of Solar System formation and origin of short-lived radionuclides, but so far have limited implications for the chronology of chondritic components. The chronological significance of oxygen–isotope compositions of chondritic components is limited. The following general picture of formation of chondritic components is inferred. CAIs and AOAs were the first solids formed in the solar nebula ∼4567–4568
Myr ago, possibly within a period of <0.1
Myr, when the Sun was an infalling (class 0) and evolved (class I) protostar. They formed during multiple transient heating events in nebular region(s) with high ambient temperature (at or above condensation temperature of forsterite), either throughout the inner protoplanetary disk (1–4
AU) or in a localized region near the proto-Sun (<0.1
AU), and were subsequently dispersed throughout the disk. Most CAIs and AOAs formed in the presence of an
16O-rich (Δ
17O
∼
−24
±
2‰) nebular gas. The
26Al-poor (
26Al/
27Al)
0
<
1
×
10
−5,
16O-rich (Δ
17O
∼
−24
±
2‰) CAIs – FUN (fractionation and unidentified nuclear effects) CAIs in CV chondrites, platy hibonite crystals (PLACs) in CM chondrites, pyroxene–hibonite spherules in CM and CO chondrites, and the majority of grossite- and hibonite-rich CAIs in CH chondrites—may have formed prior to injection and/or homogenization of
26Al in the early Solar System. A small number of igneous CAIs in ordinary, enstatite and carbonaceous chondrites, and virtually all CAIs in CB chondrites are
16O-depleted (Δ
17O
>
−10‰) and have (
26Al/
27Al)
0 similar to those in chondrules (<1
×
10
−5). These CAIs probably experienced melting during chondrule formation. Chondrules and most of the fine-grained matrix materials in primitive chondrites formed 1–4
Myr after CAIs, when the Sun was a classical (class II) and weak-lined T Tauri star (class III). These chondritic components formed during multiple transient heating events in regions with low ambient temperature (<1000
K) throughout the inner protoplanetary disk in the presence of
16O-poor (Δ
17O
>
−5‰) nebular gas. The majority of chondrules within a chondrite group may have formed over a much shorter period of time (<0.5–1
Myr). Mineralogical and isotopic observations indicate that CAIs were present in the regions where chondrules formed and accreted (1–4
AU), indicating that CAIs were present in the disk as free-floating objects for at least 4
Myr. Many CAIs, however, were largely unaffected by chondrule melting, suggesting that chondrule-forming events experienced by a nebular region could have been small in scale and limited in number. Chondrules and metal grains in CB chondrites formed during a single-stage, highly-energetic event ∼4563
Myr ago, possibly from a gas-melt plume produced by collision between planetary embryos.
We investigate the enrichment of the pre-solar cloud core with short-lived radionuclides, especially sup 26Al. The homogeneity and the surprisingly small spread in the ratio sup 26Al/sup 27Al ...observed in the overwhelming majority of calcium-aluminium-rich inclusions in a vast variety of primitive chondritic meteorites places strong constraints on the formation of the solar system. After discussing various scenarios including X-winds, asymptotic giant branch stars, and Wolf-Rayet stars, we come to the conclusion that triggering the collapse of a cold cloud core by a nearby supernova (SN) is the most promising scenario. In summary, we envision an environment for the birthplace of the solar system 4.567 Gyr ago similar to the situation of the pillars in M16 nowadays, where molecular cloud cores adjacent to an Hii region will be hit by an SN explosion in the future. We show that the triggered collapse and formation of the solar system as well as the required enrichment with radioactive sup 26Al are possible in this scenario.
The accumulation and spatial distribution of economically important petroleum in sedimentary basins are primarily controlled by its migration from source rocks through permeable carrier beds to ...reservoirs. Tracing petroleum migration entails the use of molecular indices established according to sorption capacities of polar molecules in migrating petroleum. However, little is known about molecular sorption capacities in natural migration systems, rendering these indices unreliable. Here, we present a new approach based on a novel concept of relative sorption coefficient for quantitatively assessing sorption capacities of polar molecules during natural petroleum migration. Using this approach, we discovered previously unrecognized "stripping" and "impeding" effects that significantly reduce the sorption capacities of polar compounds. These discoveries provide new insights into the behaviors of polar compounds and can easily explain why traditional molecular indices yield incorrect information about petroleum migration. In light of these new findings, we established new molecular indices for tracing petroleum migration. We demonstrate via case studies that the newly established indices, unlike traditional molecular indices, are reliable and effective in tracing petroleum migration. Our approach can be applied to diverse basins around the world to reveal distribution patterns of petroleum, which would decrease environmental risks of exploration by reducing unsuccessful wells.
The flatness of the lead cathode plate affects the electrolytic efficiency of lead and the production efficiency of the whole lead electrolytic industry. However, the dynamic response of the force ...control system of the leveler is slow, and the anti-interference and robustness are poor. By comparing proportion integration differentiation (PID) control and feedback linearized synovial control two control strategies, MATLAB software was used for modeling and simulation analysis. The results show that the system with feedback linearized sliding mode control has faster response, higher precision and better robustness.
Methionine aminopeptidases (MetAPs), which remove methionine residue from newly synthesized polypeptide chains, are a class of metalloproteases ubiquitously distributed in both eukaryotes and ...prokaryotes. MetAP-2 inhibition can induce G1 cell cycle arrest, cytostasis in tumor cells in vitro and inhibition of tumor growth in vivo. The discovery of fumagillin with potent antiangiogenic and antiproliferative activities promoted the development of fumagillin analogues as a novel class of anticancer agents. Early drug discovery efforts have focused on analogs of fumagillin, which irreversibly inhibit MetAP-2 through covalent modification of an epoxide. Several fumagillin analogs, like CKD-732, TNP-470 and PPI-2458, were found to be potent selective inhibitors of MetAP-2 (proteolytic activity) and endothelial cell proliferation. Further, they have entered in clinical trials for the treatment of different types of tumors. Recently, attention has been paid to reversible human MetAP-2 inhibitors, such as bengamides, 2-hydroxy-3-aminoamides, anthranilic acid sulfonamides and triazole analogs, which have demonstrated their potential to inhibit angiogenesis and tumor growth in vivo as well. This review article mainly discussed the development of MetAP-2 inhibitors in cancer therapy and also summarized their structure-activity relationships.
Purpose
We investigated the population pharmacokinetics and exposure-response relationship of nilotinib in patients with newly diagnosed chronic myeloid leukemia (CML) in chronic phase.
Methods
...Nilotinib was given at 300 mg or 400 mg twice daily. Serum concentration data (sparse and full pharmacokinetic profiles) were obtained from 542 patients over 12 months. A population pharmacokinetic analysis was performed using nonlinear mixed-effect modeling. Exposure-response relationships were explored graphically or using logistic regression models.
Results
Nilotinib concentrations were stable over 12 months. Patients in the 400 mg twice-daily arm had an 11.5% higher exposure than did those in the 300 mg twice-daily arm, and the relative bioavailability of nilotinib 400 mg twice daily was 0.84 times that of 300 mg twice daily. Patient demographics did not significantly affect nilotinib pharmacokinetics. The occurrence of all-grade total bilirubin elevation was significantly higher in patients with higher nilotinib exposure, and a positive correlation was also observed between nilotinib exposure and QTcF change on electrocardiograms from baseline. There was no significant relationship between nilotinib exposure and major molecular response at 12 months.
Conclusions
There is a less than proportional dose-exposure relationship between nilotinib 300 mg and 400 mg twice-daily doses. Blood level testing is unlikely to play an important role in the general management of patients with newly diagnosed CML treated with nilotinib.
This study was aimed to identify the residence of human fibrocartilage stem cells (hFCSCs), characterize their stem cell properties and investigate the functional mechanisms which regulate ...fibrocartilage stem cells (FCSCs) toward chondrogenic differentiation during cartilage homeostasis and repairing.
Cytological characteristics of hFCSCs and human orofacial mesenchymal stem cells (hOFMSCs) were analyzed. Chondrogenic potential of hFCSCs was compared with hOFMSCs both in vitro and in vivo. Regulatory role of SOX9 during FCSCs chondrogenesis was studied by shRNA interference in vitro, and by GFP+ FCSCs treatment in rat condylar cartilage defect model. SOX9 expression was also examined in temporomandibular joint osteoarthritis (TMJOA) patients’ cartilage surface.
hFCSCs exhibited typical mesenchymal stem cell characteristics, with significantly stronger chondrogenic capability compared to hOFMSCs. Moreover, hFCSCs showed remarkably increased expression of SOX9. During cartilage pellet culture, there was stronger SOX9 expression in hFCSCs than hOFMSCs. SOX9 shRNA interference downregulated chondrogenic capability of hFCSCs in vitro, as well as disrupting migration and chondrogenic differentiation of GFP+ FCSCs toward mature chondrocytes in rat condylar cartilage defect. Of note, SOX9 expression was also found suppressed in the condylar superficial zone of TMJOA patients.
We found the existence of FCSCs in human TMJ cartilage, and characterized their distinct stem cell features. SOX9 is essential for hFCSCs chondrogenic differentiation, and a comprehensive understanding of the regulatory role of SOX9 in hFCSCs would be important for exploring potential intervention strategy of condylar cartilage degradation during TMJ disorders.
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