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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.

In this study, the design and asymmetric synthesis of a series of chiral targets of orientational chirality were conducted by taking advantage of N-sulfinylimine-assisted nucleophilic addition and modified Sonogashira catalytic coupling systems. Orientational isomers were controlled completely using alkynyl/alkynyl levers [C(sp)-C(sp) axis] with absolute configuration assignment determined by X-ray structural analysis. The key structural element of the resulting orientational chirality is uniquely characterized by remote through-space blocking. Forty examples of multi-step synthesis were performed, with modest to good yields and excellent orientational selectivity. Several chiral orientational amino targets are attached with scaffolds of natural and medicinal products, showing potential pharmaceutical and medical applications in the future. [ABSTRACT FROM AUTHOR]

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]

The objectives of this study were (1) to investigate the effect of extracts from some plants in the families Nelumbonaceae and Nymphaeaceae on phosphodiesterase 5 (PDE5) and arginase, which have been used in erectile dysfunction treatment, and (2) to isolate and identify the compounds responsible for such activities. The characterization and quantitative analysis of flavonoid constituents in the active extracts were performed by HPLC. Thirty-seven ethanolic extracts from different parts of plants in the genus Nymphaea and Victoria of Nymphaeaceae and genus Nelumbo of Nelumbonaceae were screened for PDE5 and arginase inhibitory activities. The ethanolic extracts of the receptacles and pollens of Nelumbo nucifera Gaertn., petals of Nymphaea cyanea Roxb. ex G.Don, Nymphaea stellata Willd., and Victoria amazonica (Poepp.) Sowerby and the petals and receptacles of Nymphaea pubescens Willd. showed IC50 values on PDE5 of less than 25 μg/mL while none of the extracts showed effects on arginase. The most active extract, N. pubescens petal extract, was fractionated to isolate and identify the PDE5 inhibitors. The results showed that six flavonoid constituents including quercetin 3'-O-β-xylopyranoside (1), quercetin 3-methyl ether 3'-O-β-xylopyranoside (2), quercetin (3), 3-O-methylquercetin (4), kaempferol (5) and 3-O-methylkaempferol (6) inhibited PDE5 with IC50 values at the micromolar level. [ABSTRACT FROM AUTHOR]

In this paper, an explosive cyclone (EC) that occurred over Northeast China in the spring of 2016 is studied by using 6.7 μm FY satellite water vapor (WV) imagery and NCEP (1°×1°) reanalysis data. Moreover, the evolutions of the upper-level jet stream (ULJ), the vertical motions, and the potential vorticity (PV) are analyzed in detail. Results show that different shapes of the WV image dark zones could reflect different stages of the EC. At the pre-explosion stage, a small dark zone and an S-shaped baroclinic leaf cloud can be found on the WV imagery. Then the dark zone expands and the leaf cloud grows into a comma-shaped cloud at the explosively developing stage. At the post-explosion stage, the dark zone brightens, and the spiral cloud forms. The whole process can be well described by the WV imagery. The dynamic dry band associated with the sinking motion and the ULJ can develop into the dry intrusion later, which is an important signal in forecasting the EC and should be paid attention to when analyzing the WV imagery. Furthermore, the mechanism is also analyzed in detail in this article. EC usually occurs in the left-exit region of the 200-hPa jet and the region ahead of the 500-hPa trough where there is significant positive vorticity advection (PVA). When the EC moves onto the sea surface, the decreased friction would favour the development of the EC. The upper-level PVA, the strong convergence at low level, and the divergence at high levels can maintain the strong updraft. Meanwhile, the high PV zone from the upper levels extends downward, approaching the cyclone. Together, they keep the cyclone deepening continuously. [ABSTRACT FROM AUTHOR]

Film cooling via tangential wall injection is universally employed to alleviate serious aerodynamic heating of the optical window in high-speed target-seeking vehicles; nevertheless the imaging quality should be concomitantly concerned due to the turbulence-aberrated aero-optical phenomenon. This flow phenomenon can be essentially abstracted into the combinational mixing layer and turbulent boundary flow configuration, enabling numerical investigation using an explicit fifth-order weighted compact nonlinear scheme (WCNS-E-5) and a ray-tracing method. The current study considers both the aero-optical effect in a prescribed light pupil and the wall temperature under adiabatic conditions, with snapshots of vorticity contours in the symmetric plane and the wall normal density fluctuation introduced as auxiliary variables for analyzing the flowfield behavior. A parametric investigation on tangential wall injection is conducted by altering the Mach number, total temperature, and total pressure consequently via a variable-controlling procedure. The results reveal that the mutual realization of aero-optical and aero-heating reduction presents considerable difficulty, so that the future optimization of the operating conditions is suggested for engineering applications. [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]

Abstract: The first and enantioselective total synthesis of (+)‐plumisclerin A, a novel unique complex cytotoxic marine diterpenoid, has been accomplished. Around the central cyclopentane anchorage, a sequential ring‐formation protocol was adopted to generate the characteristic tricycle[4.3.1.01,5]decane and trans‐fused dihyrdopyran moiety. Scalable enantioselective LaIII‐catalyzed Michael reaction, palladium(0)‐catalyzed carbonylation and SmI2‐mediated radical conjugate addition were successfully applied in the synthesis, affording multiple grams of the complex and rigid B/C/D‐ring system having six continuous stereogenic centers and two all‐carbon quaternary centers. The trans‐fused dihyrdopyran moiety with an exo side‐chain was furnished in final stage through sequential redox transformations from a lactone precursor, which overcome the largish steric strain of the dense multiring system. The reported total synthesis also confirms the absolute chemistries of natural (+)‐plumisclerin A. [ABSTRACT FROM AUTHOR]

Enantioselective total syntheses of lycopodium alkaloids lycoposerramine-V and 5- epi-lycoposerramine-V have been accomplished. Features of the newly established total synthesis include: 1) introduction of the first chiral center with a scalable desymmetrization reaction of an meso-anhydride; 2) chemoselective functionalization of a bis-Weinreb-amide with Grignard addition; and 3) construction of the multifunctionalized cyclohexanone with a stereoselective intramolecular Michael addition. [ABSTRACT FROM AUTHOR]

Abstract: Unlike other members of HSP70 family, GRP78 manifests multifaceted subcellular distribution and forms complex with different signals, resulting in its close correlation with various tumors. However, its expression profile and function in glioma remain less well defined. In this study, normal brain tissue and astrocytic tumor specimens were evaluated for GRP78 expression, which was shown to be up-regulated in astrocytoma compared with normal tissue, increased markedly as astrocytoma pathologic grade escalates, and can still be enhanced for disease recurrence. By employing Cox regression analyses, high GRP78 expression was correlated with a poorer outcome for recurrent glioblastoma patients. In addition, immunofluorescence microscopy detected cell surface positioning of GRP78 on human glioma cells. After transfection with siRNA or antibody ligation of surface GRP78, phosphorylation of Akt and ERK was attenuated. These findings indicate that GRP78 plays an important role in astrocytoma malignancy, whereas its cell surface localization may be attractive for clinical utilization. [ABSTRACT FROM AUTHOR]

The flow past a cylinder is a classical problem in flow physics. In a certain range of Reynolds number, there will be Karman vortex street phenomenon in the wake of a cylinder, which will greatly increase the pressure drag of the cylinder. By controlling the vortex shedding phenomenon, drag reduction of the cylinder could be effectively realized. In this paper, a NACA0012 airfoil with pitching oscillation is placed downstream of the cylinder. Based on the tight coupling method, kinematics equations and Navier–Stokes equations in the arbitrary Lagrangian–Eulerian form are solved. Firstly, the effect of airfoil oscillation period and the distance between airfoil leading edge and cylinder center (x/D) are studied respectively, especially considering the aspects of vortex shedding and drag reduction effect. Besides, the vortex interaction in the flow field around the airfoil and cylinder is analyzed in detail. It is found that the NACA0012 airfoil with pitching oscillation can change the period of vortex shedding. Moreover, it can also increase the drag reduction rate to as high as 50.5%, which presents a certain application prospect in the engineering drag reduction field, e.g., for launch vehicles, ship masts, submarine pipelines, etc. [ABSTRACT FROM AUTHOR]

Esters can be successfully reduced to the corresponding alcohols with potassium borohydride/lithium chloride under microwave irradiation without solvent. The reactions are generally completed in 2–8 minutes, with the yields varying from 55% to 95%. [ABSTRACT FROM AUTHOR]

Abstract: 14-3-3 proteins comprise a large family of highly conserved, acidic polypeptides, expressed in all eukaryotic organisms, with highest concentration found in the brain. Multiple isoforms of 14-3-3 proteins have been shown to play an essential role in regulating differentiation, proliferation and transformation. In the previous study, the expression levels of all seven 14-3-3 isoforms were examined in astrocytoma. However, the expression of seven 14-3-3 isoforms in meningioma still remains unknown. This study is the first examination of 14-3-3 isoforms in three grades of meningioma by immunohistochemistry. 14-3-3ε, ζ and θ were specifically expressed in meningioma, and their expression levels increased with the increase of pathological grade of meningioma. The 14-3-3 η, β, γ and σ isoforms were negatively expressed in meningioma. In conclusion, The 14-3-3 ε, ζ and θ may be involved in tumorigenesis of meningioma and be efficient markers for predicting the degree of malignancy in meningioma. [Copyright &y& Elsevier]

The banana (Musa acuminata L. AAA group), a typical climacteric fruit, undergoes a postharvest ripening process that plays a crucial role in commercial banana fruit quality and shelf-life. To gain a better understanding of the postharvest ripening of the banana at the molecular level, we conducted a cDNA microarray analysis on banana fruit 10d after harvest, which was the time of ripening initiation by ethylene biosynthesis. A total of 16 cDNAs were found to be up-regulated and six down-regulated. These results were confirmed by using reverse transcriptase-polymerase chain reaction (RT-PCR). The cDNAs identified are involved in signal transduction, amino acid metabolism, lipid metabolism, proteolysis, citrate biosynthesis and metabolism, and the uptake and transport of potassium. The information generated in this study provides new clues to aid in understanding the regulation of ethylene biosynthesis initiation in postharvest banana ripening. [Copyright &y& Elsevier]