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An automated approximate model generation platform integrating the vehicle type generation, grid division and CFD resistance calculation is established, and the approximate model is obtained based on underwater vehicle resistance. Three approximate models of RSM model, RBF model and Kriging model were compared, and the error results were analyzed. The four-order RSM model with different speed is established, and the different speed model is weighted fitting and the approximate model of multi-speed fitting is obtained, which can be applied to the resistance optimization of multi-speed interval. Based on the intelligent optimization platform of fitting approximation model, MIGA algorithm is adopted to optimize the displacement volume, the longitudinal position of the floating center and the resistance, and get the optimal underwater vehicle type.

The experiment aimed to investigate the effects of microbial preparations on the growth and intestinal microbiota of crucian carp. Three hundred evenly sized crucian carp were randomly divided into five groups, with three replicates in each group, and 20 fish in each replicate. The group A was fed a feed containing mixed lactic acid bacteria preparations, the group B was fed a feed containing mixed Clostridium butyricum preparations, the group C was fed a feed containing a mixture of lactic acid bacteria and Clostridium butyricum preparations, the group D was fed a feed containing a mixture of lactic acid bacteria, Clostridium butyricum preparations, and 3 mg/g nano-selenium. The control group (CK group) was fed a basic feed. The experimental period lasted for 28 days. The results showed that the weight gain rate of crucian carp in the group A, group B, and group D was higher than that in the CK group ( P<0.05). The condition factor and feed coefficient of crucian carp in the group A were higher than those in the CK group ( P<0.05). The hepatopancreas SOD activity of crucian carp in the group D was higher than that in the CK group ( P<0.05), and the hepatopancreas LZM activity in the group B was higher than that in the CK group ( P<0.05). The abundance of Fusobacteria in the intestines of crucian carp in the group A significantly increased, while the abundance of Bacteroidetes in the intestines of crucian carp in the group B significantly increased. The study indicates that adding lactic acid bacteria, Clostridium butyricum, and nano-selenium to the feed can promote the growth of crucian carp, alter the community structure of the intestinal microbiota, and inhibit harmful bacteria in the intestines. [ABSTRACT FROM AUTHOR]

Cabotegravir is an integrase strand transfer inhibitor (INSTI) for HIV treatment and prevention. Cabotegravir-based long-acting pre-exposure prophylaxis (PrEP) presents an emerging paradigm for infectious disease control. In this scheme, a combination of a high efficacy and low solubility of anti-infection drugs permits the establishment of a pharmaceutical firewall in HIV-vulnerable groups over a long period. Although the structure-activity-relationship (SAR) of cabotegravir as an INSTI is known, the structural determinants of its low solubility have not been identified. In this work, we have integrated multiple experimental and computational methods, namely X-ray diffraction, solid-state NMR (SSNMR) spectroscopy, solution NMR spectroscopy, automated fragmentation (AF)-QM/MM and density functional theory (DFT) calculations, to address this question. The molecular organization of cabotegravir in crystal lattice has been determined. The combination of very-fast magic-angle-sample-spinning (VF MAS) SSNMR and solution NMR, as supported by AF-QM/MM and DFT calculations, permits the identification of structural factors that contribute to the low aqueous solubility of cabotegravir. Our study reveals the multitasking nature of pharmacophores in cabotegravir, which controls the drug solubility and, meanwhile, the biological activity. By unraveling these function-defining molecular features, our work could inspire further development of long-acting HIV PrEP drugs. [ABSTRACT FROM AUTHOR]

Background: The role of carbohydrate antigen 19‐9 (CA 19‐9) in response assessment among patients with intrahepatic cholangiocarcinoma (iCCA) remains unknown. The authors studied the association of the CA 19‐9 response (defined as a reduction >50% from baseline) with the radiologic response and the outcome in patients with unresectable iCCA. Methods: A prospective cohort of 422 patients who were initially diagnosed with unresectable iCCA, had baseline CA 19‐9 levels ≥100 U/mL, and received treatment with systemic therapies at the authors' institution between January 2017 and December 2021 were enrolled in this study. The radiologic response was assessed using the Response Evaluation Criteria in Solid Tumors version 1.1. A landmark assessment of the CA 19‐9 response and the radiologic response was performed. The associations between CA 19‐9 response and imaging response, progression‐free survival (PFS), and overall survival (OS) were analyzed. Results: Two hundred sixty‐seven patients (63.3%) had a CA 19‐9 response. A CA 19‐9 response was observed in 123 of 132 (93.2%) radiologic responders and in 144 of 290 (49.7%) radiologic nonresponders (p <.001). CA 19‐9 responders outperformed nonresponders in median PFS (10.6 vs. 3.6 months; hazard ratio [HR], 4.8 months; 95% confidence interval [CI], 3.8–6.0 months; p <.001) and OS (21.4 vs. 6.3 months; HR, 5.3 months; 95% CI, 4.2–6.7 months; p <.001). The common independent predictors of both OS and PFS included metastasis, CA 19‐9 nonresponder status, and radiologic nonresponder status in multivariable analysis. Conclusions: CA 19‐9 response is a valuable addition to assess tumor response and is associated with improved outcomes in patients with iCCA. Achieving a CA 19‐9 response should be one of the therapeutic objectives of patients with iCCA after systemic therapies. Plain language summary: A decline in carbohydrate antigen 19‐9 levels from elevated baseline levels should be one of the therapeutic aims of patients with intrahepatic cholangiocarcinoma who are managed with systemic therapies. [ABSTRACT FROM AUTHOR]

Aero-optical reduction in flat-plate turbulent boundary layer has been widely concerned due to critical application for high-speed target-seeking vehicles. From the perspective of disciplinary intersection between aerodynamic and optical engineering, the turbulence-aberrated optical behaviour, in high-Reynolds-number supersonic freestream, is numerically investigated using the in-house code High-Order SimulaTor for Aerodynamics (HOSTA) and ray-tracing scheme. To evaluate the efficiency of wall cooling strategy to reduce the detrimental aero-optical distortions, the authors leverage the theoretical equation deduced from Sutton statistic model for mutual verification with the simulative results. Additionally, based on the beneficial wall cooling effects on turbulent aero-optical reduction, comparison suggests that refrigeration directly towards the turbulence section is the most effective rather than cooling the laminar or transitional region. In further discussion, wall blowing, suction and combinational blowing and suction schemes are issued. Results reveal the rationality of employing proper suction amplitude to modify the flow into laminar state, and sufficiently high suction intensity is also promising in turbulent aero-optical reduction despite the fact of low efficiency currently. The current study puts an eye on the simulation concerning three-dimensional supersonic turbulent flow in high-Reynolds-number freestream and the application of statistic model, and future investigation is suggested for higher effectiveness of aero-optical suppression. [ABSTRACT FROM AUTHOR]

Tungsten is one of the most promising plasma-facing materials (PFMs) to be used in the nuclear fusion reactor as divertor material in the future. In this work, W2+-ions bombardment is used to simulate the neutron irradiation damage to commercial pure tungsten (W) and rolled tungsten–potassium (W–K). The 7 MeV of 3 × 1015 W2+-ions/cm2, 3 MeV of 4.5 × 1014 W2+, and 2 MeV of 3 × 1014 W2+-ions/cm2 are applied at 923 K in sequence to produce a uniform region of 100 nm–400 nm beneath the sample surface with the maximum damage value of 11.5 dpa. Nanoindentation is used to inspect the changes in hardness and elastic modulus after self-ion irradiation. Irradiation hardening occurred in both materials. The irradiation hardening of rolled W–K is affected by two factors: one is the absorption of vacancies and interstitial atoms by potassium bubbles, and the other is the interaction between potassium bubbles and dislocations. Under the condition of 11.5 dpa, the capability of defect absorption can reach a threshold. As a result, dislocations finally dominate the hardening of rolled W–K. Specific features of dislocation loops in W–K are further observed by transmission electron microscopy (TEM) to explain the hardening effect. This work might provide valuable enlightenment for W–K alloy as a promising plasma facing material candidate. [ABSTRACT FROM AUTHOR]

In the traditional sliding mode observer based sensorless field oriented control scheme for permanent magnet synchronous motor ( PMSM), the observed back-electromotive force ( EMF) exists chattering problem, and the observed rotor position is impressionable to rotational speed. Focused on these problems, a sensorless control scheme based on extended sliding mode observer is proposed in this paper. Through feeding back the estimated back-EMF to the stator current observer, and replacing the traditional switching function by saturation function, the chattering problem was improved effectively. Furthermore, the observation accuracy and anti-jamming ability was further improved by introducing the rotated influence immune phase-locked loop. Finally, compared with the traditional sliding mode observer, the experimental results based on a 2.9 kW PMSM show that the proposed scheme is immune to the back-EMF chattering, and has better dynamic performance and observation accuracy. [ABSTRACT FROM AUTHOR]

Tungsten–potassium (WK) alloy with ultrafine/fine grains and nano-K bubbles is fabricated through spark plasma sintering (SPS) and rolling process. In this study, 3-MeV W2+ ion irradiation with a tandem accelerator is adopted to simulate the displacement damage caused by neutrons. As the depth of irradiation damage layer is limited to only 500 nm, the hardening behaviors of WK alloy and ITER (International Thermonuclear Experimental Reactor)-W under several damage levels are investigated through Bercovich tip nanoindentation test and other morphological characterizations. The indenter size effect (ISE), soft substrate effect (SSE), and damage gradient effect (DGE) are found to influence the measurement of nano-hardness. Few or no pop-ins in irradiated samples are observed while visible pop-in events take place in unirradiated metals. Extensive pile-up with different morphology features around the indentation exists in both WK and ITER-W. The WK shows a smaller hardness increment than ITER-W under the same condition of displacement damage. This study provides beneficial information for WK alloy serving as a promising plasma facing materials (PFMs) candidate. [ABSTRACT FROM AUTHOR]

The corrosion behavior of nickel-based 718 alloy at seven partial pressures of H2S P H 2 S was investigated using electrochemical impedance spectroscopy (EIS) and polarization methods in 25 wt% NaCl solution at 150 °C for 168 h. The tested results show that anodic reactions are controlled alternately by the diffusion mostly, then both charge transfer and diffusion and finally charge transfer mainly with the increment of P H 2 S . The corrosive products are composed of sulfides and oxides of Ni, Cr and Fe with double layers for P H 2 S of 5.1 and 13.0 MPa and three layers for P H 2 S of 10.4 MPa according to microstructures and compositions of corrosion products characterized by the scanning electron microscope (SEM) and electron probe microanalysis (EPMA) methods. The inner oxides layer plays a critical role in anti-corrosion in a wet H2S environment at high temperature and pressure. [ABSTRACT FROM AUTHOR]