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A quantum thermal machine is an open quantum system coupled to hot and cold thermal baths. Thus, its dynamics can be well understood using the concepts and tools from non-Hermitian quantum systems. A hallmark of non-Hermiticity is the existence of exceptional points where the eigenvalues of a non-Hermitian Hamiltonian or a Liouvillian superoperator and their associated eigenvectors coalesce. Here, we report the experimental realization of a single-ion heat engine and demonstrate the effect of Liouvillian exceptional points on the dynamics and the performance of a quantum heat engine. Our experiments have revealed that operating the engine in the exact- and broken-phases, separated by a Liouvillian exceptional point, respectively during the isochoric heating and cooling strokes of an Otto cycle produces more work and output power and achieves higher efficiency than executing the Otto cycle completely in the exact phase where the system has an oscillatory dynamics and higher coherence. This result opens interesting possibilities for the control of quantum heat engines and will be of interest to other research areas that are concerned with the role of coherence and exceptional points in quantum processes and in work extraction by thermal machines. Investigations of quantum thermal machines and Liouvillian exceptional points have rarely crossed each other. Here, the authors realize experimentally a quantum Otto engine using a single trapped ion, and show that crossing a Liouvillian exceptional point during the cycle increases the engine performance.

MicroRNAs have been shown to play an important role in normal hematopoisis and leukemogenesis. Here, we report function and mechanisms of miR-181 family in myeloid differentiation and acute myeloid leukemia (AML). The aberrant overexpression of all the miR-181 family members (miR-181a/b/c/d) was detected in French–American–British M1, M2 and M3 subtypes of adult AML patients. By conducting gain- and loss-of-function experiments, we demonstrated that miR-181a inhibits granulocytic and macrophage-like differentiation of HL-60 cells and CD34+ hematopoietic stem/progenitor cells (HSPCs) by directly targeting and downregulating the expression of PRKCD (which then affected the PRKCD-P38-C/EBPα pathway), CTDSPL (which then affected the phosphorylation of retinoblastoma protein) and CAMKK1 . The three genes were also demonstrated to be the targets of miR-181b, miR-181c and miR-181d, respectively. Significantly decreases in the expression levels of the target proteins were detected in AML patients. Inhibition of the expression of miR-181 family members owing to Lenti-miRZip-181a infection in bone marrow blasts of AML patients increased target protein expression levels and partially reversed myeloid differentiation blockage. In the mice implanted with AML CD34+ HSPCs, expression inhibition of the miR-181 family by Lenti-miRZip-181a injection improved myeloid differentiation, inhibited engraftment and infiltration of the leukemic CD34+ cells into the bone marrow and spleen, and released leukemic symptoms. In conclusion, our findings revealed new mechanism of miR-181 family in normal hematopoiesis and AML development, and suggested that expression inhibition of the miR-181 family could provide a new strategy for AML therapy.

Quantum lock-in detection (QLID) is a powerful technique for extracting weak oscillating signals within noise. While entanglement may enhance measurement precision beyond the standard quantum limit (SQL), its integration with QLID is still an experimental challenge. Here we report the first experimental realization of entanglement-enhanced QLID using two trapped 40 Ca + ions. We prepare a Greenberger-Horne-Zeilinger (GHZ) state using a M ϕ lmer-S ϕ rensen gate and then apply periodic multipulse sequences to execute QLID. Using the GHZ state, the measurement precision approaches the Heisenberg limit ( Δ ω  ∝  N −1 ), surpassing the SQL ( Δ ω  ∝  N −1/2 ) achievable with non-entangled states. Notably, QLID achieves a superior inverse-quadratic temporal scaling ( Δ ω  ∝  T −2 ), exceeding the conventional inverse-linear scaling ( Δ ω  ∝  T −1 ), regardless of entanglement. We further optimize pulse sequences for enhanced robustness against experimental errors. This work establishes a powerful pathway to Heisenberg-limited quantum sensing of weak oscillating signals within noise. Quantum lock-in detection (QLID) is crucial for extracting oscillating signals from noise, while quantum entanglement is vital to surpass the standard of quantum limit in precision measurement. Here, the authors experimentally realise entanglement-enhanced QLID using two trapped ions, achieving frequency measurement precision at the Heisenberg limit and demonstrating an improved inverse-quadratic temporal scaling.

A novel arc-cylinder type dielectric elastomer generator (AVI-DEG) is proposed in this paper to scavenge energy from rotational environment. The proposed AVI-DEG consists of a hollow arc cylinder, an inner rigid ball, two pairs of identical cylindrical frames and two pre-stretched dielectric elastomer membranes (DEMs). When the system is subjected to rotations, the rotational energy can be harvested through the impacts between the ball and the membranes. To simplify the complex rotations resulting from torsional vibrations and pendulum, etc., a harmonic rotational excitation is considered to act on the proposed AVI DEG. The dynamical behaviors of the proposed AVI-DEG are first analyzed theoretically, based on which the system’s energy harvesting (EH) process is further derived. The experiments measuring the output voltages of a DEM under the impacts of a ball using a single-sided impact (SSI) model, which has been conducted previously, are introduced to verify the EH process of the AVI-DEG at each impact. Furthermore, the numerical simulations are conducted to present the dynamical and electrical responses of the system under different rotational excitations, and the parametric influences of the rotational excitation (frequency and amplitude) and system’s dimensions on the system’s EH performance are discussed in detail. Research results show that appropriately setting these parameters can significantly improve the system’s EH performance. This work is also beneficial to investigating the EH performance of the system with given dimensions, or optimizing the system’s dimensions under a given rotational excitation.

In this work, 18Ni300 maraging steel was successfully fabricated, for the first time, by a laser cladding technique under atmospheric condition. The effects of different aging times (1, 3, 6, and 9 h) at 500 °C on the microstructure and mechanical properties of the as-cladded 18Ni300 maraging steel were carefully characterized and analyzed. The microhardness and tensile strength increase with increasing aging time up to 6 h, and subsequently, decrease with the time extending to 9 h. On the contrary, the elongation is shown a reverse trend. The original 18Ni300 maraging steel exhibits cellular microstructure with an average grain size of 2 µm, composed of martensite and nano-Ti 2 N particles. After aging treatment, Ni-rich nano-precipitates (Ni 3 (Mo,Ti) and Ni(Mo,Ti)) together with reverted austenite were formed and promoted with the extension of aging time. The optimal comprehensive performance of the 18Ni300 maraging steel can be obtained by aging 3 h at 500°C, with microhardness of 509 HV 0.2 , ultimate tensile strength of 1686 MPa, and elongation of 11.5%, respectively. The microstructural mechanisms accounting for the property changes are discussed in detail.

Resistance to cytotoxic chemotherapy drugs remains as the major cause of treatment failure in acute myeloid leukemia. Histone deacetylases (HDAC) are important regulators to maintain chromatin structure and control DNA damage; nevertheless, how each HDAC regulates genome stability remains unclear, especially under genome stress conditions. Here, we identified a mechanism by which HDAC3 regulates DNA damage repair and mediates resistance to chemotherapy drugs. In addition to inducing DNA damage, chemotherapy drugs trigger upregulation of HDAC3 expression in leukemia cells. Using genetic and pharmacological approaches, we show that HDAC3 contributes to chemotherapy resistance by regulating the activation of AKT, a well-documented factor in drug resistance development. HDAC3 binds to AKT and deacetylates it at the site Lys20, thereby promoting the phosphorylation of AKT. Chemotherapy drug exposure enhances the interaction between HDAC3 and AKT, resulting in decrease in AKT acetylation and increase in AKT phosphorylation. Whereas HDAC3 depletion or inhibition abrogates these responses and meanwhile sensitizes leukemia cells to chemotoxicity-induced apoptosis. Importantly, in vivo HDAC3 suppression reduces leukemia progression and sensitizes MLL-AF9 + leukemia to chemotherapy. Our findings suggest that combination therapy with HDAC3 inhibitor and genotoxic agents may constitute a successful strategy for overcoming chemotherapy resistance.

This paper provides a comprehensive review of the literature regarding actuator systems which are based on the principle that combines the friction and inertia effect, named friction–inertia principle in this paper; such actuators is called friction–inertial actuator (FIA). The contribution of this paper lies in the generalization of various published (including patented) FIAs into a general principle with three specific principles. They are further taken as a framework upon which various published FIAs are classified and compared in terms of their principle, structure, and performance. In addition, this paper shows how this framework would allow for further innovation on FIAs. In the process of this generalization and classification, some confusion presented in the literature is also clarified. This paper also discusses further effort that may be taken to advance the friction–inertia actuation technology.

The micro stick-slip motion systems, such as piezoelectric stick-slip actuators (PE-SSAs), can provide high resolution motions yet with a long motion range. In these systems, friction force plays an active role. Although numerous friction models have been developed for the control of micro motion systems, behaviors of these models in micro stick-slip motion systems are not well understood. This study (1) gives a survey of the basic friction models and (2) tests and compares 5 friction models in the literature, including Coulomb friction model, Stribeck friction model, Dahl model, LuGre model, and the elastoplastic friction model on the same test-bed (i.e. the PE-SSA system). The experiments and simulations were done and the reasons for the difference in the performance of these models were investigated. The study concluded that for the micro stick-slip motion system, (1) Stribeck model, Dahl model and LuGre model all work, but LuGre model has the best accuracy and (2) Coulomb friction model and the elastoplastic model does not work. The study provides contributions to motion control systems with friction, especially for micro stick-slip or step motion systems as well as general micro-motion systems.

AIMS: Soil inorganic carbon (SIC), primarily calcium carbonate, is a major reservoir of carbon in arid lands. This study was designed to test the hypothesis that carbonate might be enhanced in arid cropland, in association with soil fertility improvement via organic amendments. METHODS: We obtained two sets (65 each) of archived soil samples collected in the early and late 2000’s from three long-term experiment sites under wheat-corn cropping with various fertilization treatments in northern China. Soil organic (SOC), SIC and their Stable ¹³C compositions were determined over the range 0–100 cm. RESULTS: All sites showed an overall increase of SIC content in soil profiles over time. Particularly, fertilizations led to large SIC accumulation with a range of 101–202 g C m⁻² y⁻¹ in the 0–100 cm. Accumulation of pedogenic carbonate under fertilization varied from 60 to 179 g C m⁻² y⁻¹ in the 0–100 cm. Organic amendments significantly enhanced carbonate accumulation, in particular in the subsoil. CONCLUSIONS: More carbon was sequestrated in the form of carbonate than as SOC in the arid cropland in northern China. Increasing SOC stock through long-term straw incorporation and manure application in the arid and semi-arid regions also enhanced carbonate accumulation in soil profiles.

This paper proposes a nautilus-inspired bionic volute for a multiblade centrifugal fan. Analysis of the noises generated by the fan is presented. This is made possible by a model that integrates a steady-state equation using the Reynolds-averaged Navier-Stokes (RANS) model and an unsteady-state estimation using the large-eddy simulation (LES) model and the Ffowcs Williams-Hawkings aerodynamic noise model, and by numerical solution to the model. Our computational model is validated on the sound pressure level with the help of the measurements on a physical system. The validation suggests that the proposed bionic volute significantly increases the aerodynamic performance particularly in terms of transformation between the pressure and flow rate under the rated power. The noise associated to the bionic volute is found to be predominantly tonal noise, and this is the primary source of the noise of the fan. Another finding is that the large expansion profile of the proposed volute contributes to the attenuation of the tonal noise associated to the periodic jet impingement at the impeller outlet.